CA2148554A1 - Reversible chemical thermometer - Google Patents

Abstract

A composition of matter suitable for use in a reversible thermometer is disclosed which comprises a thermally responsible material capable of being supercooled at least for several minutes, and subject to a change in state from a solid to a liquid substantially at a predetermined temperature; means for visually observing the change in state; and a matrix forming material comprising an amorphous organic compound, the matrix forming material being insoluble in the thermally responsive material; whereby the thermally responsive material is dispersed within the matrix forming material, the composition of matter being reversibly responsive to changes in temperature, and remaining in the liquid state for a time sufficient to permit a user of the composition to observe the change in state. The preferred matrix forming material is polyisobutylene, and the preferred thermally responsive material is a solid solution of ortho-chloronitrobenzene and ortho-bromonitrobenzene. A process is disclosed for preparing the composition of matter.

Description

~ 21 48554 FIELD OF THE INVENTION
This invention relates to a chemical thermometer. In particular it relates to a chemical type clinical thermometer which holds its signal for a time sufficient to be read, but reverses to its original condition thereafter.

U.S. Patent No. 3,946,612,incorporated herein by reference, discloses a clinical thermometer comprising a plurality of cavities filled with solid solutions of two thermally responsive materials in each pocket. The melting point of the contents of each pocket varies as a result of the ratio of the two compounds in 10 each pocket. The compositions are compounded to cover the clinical temperature range in 0.2 F. increments. The prerelled thermally responsive material comprises a solid solution of ortho-chloronitrobenzene and ortho-bromonitrobenzene (OCNB and OBNB respectively).
The composition of U.S. Patent No.3,946,612,is subject to a supercooling phenomenon. Upon melting the composition remains in the liquid state long after the composition has been brought to a temperature below its melting point. For the thermometers of the type contemplated by the prior art this presented problems, and means were devised to cause the compositions to solidify rapidly upon being cooled below their melting point.
U.S.Patent No.3,980,581discloses compositions useful as nucleating agents in the OCNB/OBNB solid solutions of the prior art. These nucleating agents are `` - 21 4~554 salts of metals and include sodium borate, cryolite, sodium acetate and cobalt chloride.
The nucleating agents of the '581 patent though effective were subject to a "poisoning" effect. As the thermally responsive materials were subjected to 5 melting and resolidification cycles the nucleating agent pores eventual became filled with the thermally responsive material. As a result, the nucleating agent became ineffective. This "poisoning" problem was solved by the invention disclosed in U.S. Patent No.3,956,153,incorporated herein by lcrelellce.
The '153 patent discloses a lcgenelative nucleating agent comprising a 10 compound which is sparingly soluble in the thermally responsive material.
Although a minor amount of material dissolves into the thermally responsive material when it melts, sufficient undissolved material remains to act as a nucleating agent. Because the nucleating agent is sparingly soluble, its surface is contin-l~lly regenel~tcd, and no poisoning effect is observed.
U.S. Patent No. 4,397,570discloses a disposable thermometer similar to that of Hof et al. 4,232,552,incorporated herein by lefelcnce, which utilizes a pres~ulc sensitive adhesive cont~ining a nucleating agent to make a thermometer which is reversible and m~int~in.~ its signal for about 3-5 minutes. The adhesive utilized is the polyisobutylene adhesives of U.S.4,189,942,incorporated herein by 20 leÇelcnce. The nucleating agents are generally mineral type compositions such as talc, gibbsite, calcium alllmin~te, etc.

U.S. Patent No. 4,248,089discloses a reversible thermometer wherein the telllpel~lule sensitive material comprises a combination of high molecular weight fatty acids. A nucleating agent which both allows the thermometer to be reversible and at the same time hold its signal for a reasonable period of time to 5 be read is included. Suitable nucleating agents include dyes such as Auramine, Acridine Yellow, Red, and Orange; Rhodamine and Sudan Black.
U.S. Patent No. 4,299,727 to Hof discloses a reversible thermometer lltili7.illg a heat sensi~ive composition, preferably that of Hof et al. U.S. Patent No.
4,232,552;a matrix forming amorphous material and a film forming material which 10 is more crystalline than the matrix forming compound. The heat sensitive composition can be a ortho-chloronitrobenzene (OCNB), ortho-bromonitro-benzene (OBNB), l-thymol, 2-naphthol and naphth~linP. The matrix forming amorphous material can comprise microcrystalline waxes and polyisobutylene.
Suitable film forming materials include high melting aliphatic alcohols. Optionally, 15 a solublizing material such as docosanol can be included. The preferred heat sensitive composition is a combination of OCNB and OBNB.
U.S. Patent No. 4,150,572discloses a reversible thermometer wherein the signal is m~int~inPd for a reasonable period by the addition of a polymer to a thermally sensitive material. The preferred thermally sensitive material is a 20 combination of OCNB and OBNB. The polymer must be soluble in the thermally sensitive material at a level of about 10 to 75 wt. % based on the thermally sensitive material at the melting point of the thermally sensitive material. Suitable polymers include the thermoplastic polymers such as polystyrene, polyacrylates and polyvinyl butyral.
Preselllly, the only commercially available chemical type thermometer 5 utili7.ing the solid solutions of the '612 patent is a device disclosed and claimed in U.S. Patent No. 4,232,552,incorporated herein by reference. While the patent discloses compositions utili7.ing the prior art nucleating agents the device being marketed contains no nucleating agent. That thermometer relies on the supercooling effect to give a signal which is retained for a time sufficient to be 10 read. Since the thermometer is sold as a single use devise, reversal of the signal is not required. Use of the prior art nucleating agents, however, results in a reversal which is too rapid for use where the device is to be read after it is removed from the heat source, the mouth for example. In order for the device of the '552 patent to be reusable it must revert to its original solid state in a 15 reasonable amount of time while at the same time hold a signal to be read for a time sufficient to permit the user to read the temperature shown.
SUMMARY OF THE INVENTION
It has surprisingly been found that a reversible thermometer can be prepared by forming a matrix of an amorphous organic compound in which a 20 thermally sensilive material is insoluble at the lellll?eldl~lle to be indicated by the thermally sensitive material. The preferred thermally sensitive material is a solid 2 ! ~L8554 solutionofo-chloroniLlobenzene (OCNB) and o-bromonitrobenzene (OBNB). The matrix forming amorphous material is preferably a polymer, e.g. ,polyisobutylene.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial elevation view of a flat or gradll~tec1 curved prior art S heat-con-lllcting carrier having a cavity defined therein, which cavity forms an enclosure for a tellll)eldture sensiLive "classical" composition of matter therein when such cavity is covered by a transparent cover sheet means in sealing engagement with carrier means overlaying the heat conducting carrier means and above the cavity;
FIG. 2 is a partial plan view of a device over a part of the clinical range of temperatures embodying the principles of the prior art U.S. Patent No.
4,232,552in degrees Celsius;
FIG. 3A and 3B are, respectively, a plan view of a prior art flat temperature in~lic~ting device comprising a heat confll~cting carrier means with a 15 grid of cavities thereon; and an elevation view taken along line 13 13in FIG. 3A
revealing the heat conducting carrier means within Ll~n~alellL cover sheet means and a bottom plate means;
FIG. 4 is a cross-sectional view of a flat or gradually curved heat conducting carrier having a cavity defined therein, where a cover layer is bonded 20 to a carrier layer by a ples~uLe sensilive adhesive layer comprising polyisobutylene (PIB) DETAILED DESCRIPTION OF THE INVENTION
This invention relates to chemical type thermometers. In particular it relates to reversible clinical thermometers of the chemical type. Chemical thermometers are those thermometers which use a normally solid chemical (organic) compound as the temperature sensitive material instead of mercury or other liquid materials.
Specifically this invention relates to method and composition for preparing a reversible thermometer of the chemical type. Generally, clinical chemical thermometers require that the thermally sensitive materials be subject to some degree of supercooling so that the user will have sufficient time to read the thermometer after it is removed from the patient. Super cooling refers to the phenomenon which m~int~in~ a normally solid material in the liquid state after it has been melted and its l~lllpela~ure is reduced below its melting point. While any chemical thermometer may be used in the practice of this invention so long as the criteria described herein are met, the preferred chemical type thermometer is that described by Hof et al. in their U.S. Patent No. 4,232,552. In order that the advantages of the instant invention can be more readily appreciated by those skilled in the art having access to this disclosure, the disclosure of U.S. Patent No.
4,232,552 will be repeated herein in detail.
Throughout the Detailed Description below, the terms "novel thermally-responsive substance", "novel thermally-responsive material", "novel `- 2 1 48554 temperature-indicting compositions of matter", "noveltemperature-sensitive solid solutions", "novel temperature-indicating solid solutions", and "novel solid solutions", or variations thereof, are used interchangeably to denote the same novel materials of the Hof '552invention. Otherwise, the term "compositions of 5 matter" or "classical compositions of matter" are used interchangeably to denote compounds which change only from being opaque to transparent with a corresponding change from the solid to liquid state, or vice versa.
1. Compositions of Matter The discovery disclosed in the Hof et al. '552patent is that certain organic 10 compounds (to be described hereinafter) form solid solutions which undergo a change in state from solid to liquid at precise and predetermined temperatures with a corresponding change in color visible to the naked eye, and likewise, form liquid solutions which undergo a change in state from liquid to solid at a predetermined telllpel~tures with a corresponding change in color visible to the 15 naked eye. The term "solid solution" is well known and usually refers to a homogeneous solution of one solid in another. The solid solutions contemplated in the present invention are composed of two or more, preferably three or four, different organic compounds with varying proportions of at least two compounds which form a solvent for the solution. Each solid solution undergoes a rapid 20 change of state at a pred~lmil~ed temperature or substantially thereabouts. By a "change in color visible to the naked eye" of a source we mean a change in the - `- 21 48554 wavelength of luminous flux of light (from the source distributing or reflecting such energy in the region of the Electromagnetic Spectrum from about 3900 Angstrom units to about 7600 Ang~llolll units before or after the change, or preferably both) visible to a person of normal vision and eyesight wherein the 5 hltellsily of the luminous flux surrounding the source is more than or about 5 lumens per square food (ft-c). in most instances, this change in the wavelength of luminous flux to the eye will be at least about 175 Angstroms, and preferably at least about 500 Angstroms.
Preferably, when a small but effective amount (generally a weight fraction 10 from about 0.005 to 0.2 weight percent, and generally about 0.05 weight percent of the entire composition, but the Oplilllulll may be more or less upon experimentation, depending on the below described Group I-III compounds, selected and the solvent selected, up until both phases appear dark, appear the same color, or the melting point becomes too broad for the use desired--some 15 latitude for ~ .elilllentation is present here) of one or more of Group III
compounds comprising: pinacyanol iodide, 1,1'-diethyl-2,2'-cyanine iodide, quinaldine red, pinacyanol chloride, thionin, methylene blue, cresol red, chloro-phenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, Orasol Orange RLNTM, Orasol Navy BlueTM, Irgalith Red PRTM, Fat Red BSTM, 20 Xylene Cyanol FFTM, Rho.l~minr. B, Rhodamine 6GTM, Irgalith Magenta TCBTM, Irgalith Pink TYNCTM, Toluidin Blue OTM, Savinyl Green B, Savinyl Blue RSTM, 21 4~554 ~ul~ulhl, 3.3"-diethyl-thiadicarbocyanine iodide, cryptocyanine, Dicyanine ATM, Merocyanine 540TM, 4-(p-ethoxy-phenylazo)-m-phenylene cli~mine mono-hydrochloride, Yellow Orange STM, Chrysoidin GTM, fuchsin, aurintricarboxylic acid (ammonium salt), Victoria Blue RTM, Pyronin GTM, gallein, Erythrosin Yellowish 5 BlendTM, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphospine OTM, acriflavin, acridine orange, rhoduline violet, Alizarin cyanin 2 RTM, Alizarin Red STM, alcannin, AurantiaTM, Direct Green GTM, Fast Red Salt 3GLTM, Fast Blue Salt BBTM, Fast Garnet Salt GBCTM, Carta Yellow G 180 o/o Murexide, Savinly Blue GLSTM, Irgalith Blue GLSMTM, phthalo-cyanine, Di Amingreen BTM, 10 Alizarin Blue S, Celiton Blue ExtraTM, neocyanine, Janus GreenTM, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow RTM, Eriochrome black TTM, Chromotrope 2RTM, Ponceau 6RTM, Brilliant Ponceau G/R/2RTM, chromolan yellow, Sudan red BTM, Bismarck brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast pink 2 BLTM, Oil Red EGNTM, Euro-glaucine, Fuchsin NBTM, 15 parafuchsin, Patent BlueTM, Irgalith Blue TNCTM, Phloxin BTM, fluorescein sodium salt, Rhodamine B baseTM, Eosinscarlet, Eosin YellowishTM, Erythrosin extrabluish, 4,5-dibromofluorescein, ethyleosin, PhloxineTM, Cyanosin BTM, chlorocresol green, pinacyanol bromide, 2-(p-dimethylamino-styryl)-1-ethyl pyridinium iodide, ethyl pyridinium iodide, ethyl red, nigrosine, savinyl blue BTM, Orasol Blue BLNTM, 20 Safranin OTM, Solophenyl Brilliant Blue FsLTM, Nile Blue ATM, gallocyanine, gall~mine blue celestine blue, methylene green, Azure A/B/CTM, Blue VIFTM, 21 48~54 OrganolTM, Alizarin, Nitrofast Green GSBTM, qllin~li7.~rine, Oil Blue NTM, Solvay purple, Ciba BlueTM, Indigo syntheticTM, Chromophtal Bordeaux RSTM, Acid Alizarin Red BTM, 5-Aminofluorescein, Rose BengalTM, Martius YellowTM, Chicago Blue 6BTM, Alcian blue 8GXTM, cresyl violet, 4,4'-Bis(dimethyl-amino)benzylhdrol, 5 Zinc Pthalocyanine, Sudan IIITM, Pyronin yTM, Toluylene BlueTM, Cresyl Violet perchlorate, Mendola's BlueTM, 3,3'-diethylthiadicarbocyanine iodide, Phosphine DyeTM, NitronTM, cresyl violet acetate, Ceres Orange RTM, 4-phenylazo-1-naphtyl-amine, 4-(4-Dimethylamino-1 naphtylazo-3-methoxybenzene sulfonic acid, Bindschedler's GreenTM, and p-(p-dimethylaminophenylazo)benzoic acid, or 10 one of the other organic moieties to be described (one or more Group I
compounds with one or more Group II compounds) is combined with a suitable solvent, for example, a pure mixture of ortho-chloLonill~-benzene (OCNB) and ortho-bromonitrobenzene (OBNB) for use in clinical applications. The lelllpel~ture of the change of state of a number of solid solutions with a 15 corresponding change incolor may be accomplished at approximately 1/10C.or 2/10 F. intervals, i.e.,a change of state of one temperature-sensitive composition of matter at a telllpelalul~ 1/10 C. or 1/5 F. different from the temperature of chance in state of another novel composition of matter in an adjacent region cont~ining another proportion of the same organic moieties in 20 ortho-chloronitrobenzene and ortho-bromonitrobenzene. Thus, for example, in human clinical applications where temperature measurements in the range of 96 F. to 105 F. (or from 35.5 C. to 40.5 C.) are usually desired, 45 to 50 different ` 2148554 solid solutions differing in their percentage compositions but otherwise made from the same two components) will provide all of the n~cec.c~ry temperature gradations atincrements of 2/10F.,i.e.,96.0,96.2,96.4,etc.,upandincluding 104.8 F., or in the alternative 35.5,35.6,35.7, up and including 40.4 C. The 5 solution of ortho-chlolol~iLlobenzene and ortho-bromonitrobenzene, when the ortho-bromonitrobenzene varies from 56.2weight percent to 96.0weight percent, provides an excellent starting mixture for determination of te~l~peldlul~s in the human clinical le~pe~ature range. Usually the addition of the Group I-III organic moieties (hereinafter sometimes "organic moieties") consisting of a small but 10 effective percentage of one or more of the aforesaid Group III compounds, or a combination of one or more Group I compounds with one or more Group II
compounds affects the temperature curve of the solid solution by only a small increment which is substantially constant along the entire curve. Regardless of the solvent system selected for a given predetermined le...peldlulc range, it is 15 n~cess~ry that the organic moieties selected for the color change constitute a small but effective amount of moieties, e.g.,at least that amount sufficient to provoke a color change visible to the naked eye, and preferably up to a saturated solution of Group I-III organic moieties, and most preferably about 0.005 to about 0.2 weight percent of an inert, preferably aromatic solvent constituents, co~ uLil1g 20 the rem~ining balance of the mixture. The Group I-Group III moieties may in some instance exceed 0.2 weight percent as long as the melting point remains .

sharp and both phases are not so dark as to elimin~t~ a color change visible to the naked eye. If too small an amount of organic moieties is employed, the colors and the color change are too faint under weak light; if too large an amount is employed, the colors are too dark and the color change is harder to visualize and 5 there is a possibility that the sharpness of the melting point will be affected. It is also noted that the organic moieties and suitable solvent to be described should be substantially free of inl~ulilies, generally, such hll~ulilies should be kept less than three tenths of one percent of the entire composition. Supersaturated solutions are not pl~felled for reasons to be enumerated below.
The dye systems (organic moieties) of the '552 patent are useful in the practice of this invention, and are incorporated into the solid solutions at a preferred conce~ tion about 0.03 wt. % to about 0.15wt. % based on the weight of solid solution plus organic moiety; more preferably at about 0.035 to about 0.1 wt. %.
It must be emphasized from the outset that once a proposed solvent system has been selected (consisting of one or more compounds) for the temperature(s) to be determin~l, the compound(s) of the system must be tested for the Group I-III moieties for stability (i.e. ,inertness) and solubility of the Group I-III moieties in the compound(s) of the solvent. This must be done by routine testing, within 20 the skill of those in the art. Only after the solvent system compound(s) are shown to dissolve the Group I-III moieties and be inert towards them, can such a solvent system be suitable for our invention.

Those skilled in the art will appreciate that organic compounds, unlike crystalline materials, exhibit a melting point range rather than a sharp melting point. For example the OCNB and OBNB exhibit a melting point range of about 2.0 F. Telllpe,dlllre readings of within about 0.2 F. or 0.1 C. are achieved by 5 selecting completion of melt temperature dir~lenliated from one another by the incremental reading desired.
While sometimes under fortuitous circumstances the solvent system may consist of only one compound, in most instances (as those skilled in the art will appreciate) the lelllpe,Ature to be dete"l,illed will not be readily obtainable 10 without mixing two or more organic compounds for the solvent system. Hence, for a temperature-indicating device, two or more related organic compound constituents in the solvent are especially helpful for measuring forty or more tempe,dlu,es located at regular increments.
It is appa~llt from the foregoing description that the selection of one or 15 more inert solvents towards the organic moieties for use in the composition of matter requires judicious and careful scl,lli"y, since not all organic compounds are useful for this purpose and many may fall outside a desired te"lpe,Alul~ range.
A suitable solvent may be any solvent which is inert towards the organic moieties and in which the organic moieties are soluble while the solvent is in the liquid 20 phase. In some instances, simple alcohols and other organic substances may be suitable rather than aromatic compounds. The organic compounds which are 21 4~554 particularly adapted for the formations of solid solutions which can serve a ten~el~ture-indicating composition in accordance with the present invention are generally those which are weakly polar (e.g. compounds which are immiscible in water and have a dielectric constant less than about 35) or moderately polar 5 aromatic organic compounds, as well as the requirements of organic moiety solubility and il~llness towards the organic moieties. Thus, it has been discovered that weakly polar or moderately polar aromatic organic compounds, which have analogous chemical structures (e.g.,analogs, homologs and optical isomers), have substantially the same molecular volume or have similar crystalline structures (e.g., 10 isomorphous) and which form the solid solutions useful for solvent system constituents in plepalillg a grid of composition of matter to be used in predetermined temperature range for the delellllillation of a temperature falling within said range. In addition, it is preferable that the solvent solutions have a linear or a substantially linear temperature composition liquidous curve, 15 particularly over the desired tellll)eldlule range such as, for example, over the human clinical Lelllpel~ture range. Exemplary weakly polar or nonpolar aromatic solvents are ortho-chloloniLlobenzene, ortho-bromonitrobenzene, naphthalene, 2-ethoxybellzanlide, l-thymol, 2-naphthol, ortho-iodonitrobenzene, meta-iodo-nitrobenzene, para-iodonitrobenzene, para-dibro-monitrobenzene and para-toluic 20 acid. It must be emphasized, of course, that a suitable solvent useful for one selection of organic moieties may not be useful for another, and that an operable ~ 2 1 48554 solvent at one temperature range may not work at a different range. It is recommended that for a given tempelaLule to be measured, one may start his investigation for the applopliate temperature(s) to be determined a suitable solvent system selected from compounds from the following:
(1) moderately polar or weakly polar aromatic compounds, i.e.,compounds having a dielectric constant of less than about 35;
(2) water; or (3) aromatic and aliphatic compounds other than (1)-(2) which are germane to the ~lnpelatures to be determined, and which are "inert" to the Group I-III
dyes.
The constituents of the compositions of matter comprise:
(1) a solvent (I) consisting of a single substance or a mixture of substances and adapted to change from a solid state at substantially a predetermined temperature to a liquid state and (2) an indicator system (II) consisting of one or more substances different from (I), characterized in that (a) (II) is soluble in (I) when the latter is in the liquid phase, and (b) (II) changes color visible to the naked eye when (I) passes from the solid to the liquid phase or from the liquid to the solid phase.
It is well within the range of knowledge of those skilled in the art to find for a given telll~eldture range to be measured, and for color change desired 21 ~8~5$

(choosing from the various Group I-III compounds) a suitable solvent, i.e.,one which is inert toward the Group I-III compounds and for which the latter a soluble in the liquid phase to said solvent.
The solid solutions made from ortho-chlolonillobenzene and ortho-bromonitrobenzene have been found to be most preferable for use in temperature measurements in the clinical range within the aforesaid accuracy. Of course, as it will be readily understood by those skilled in the art, any two or more aromaticsolvents as defined above in which the organic moieties to be described below are soluble, stable and inert, may be employed for thermometers if adaptable to the teml)el~lur~ range to be tested, and if capable together of forming a homo-geneous solid solution.
Preferably the composition of matter consists essentially of:
(A) a suitable solvent adapted to change from a solid state at a pre-determined temperature to a liquid state, and (B) an effective amount of one or more suitable organic moieties soluble in said solvent in the liquid state and adapted to change the color of the composition visible to the naked eye upon the change of state of the solvent at substantially the predetermined telllpel~lure and selected from one or more of the group consisting of (1) a group III body of single compounds consisting of the cyanine class of dyes, suitable dyes from the following classes: monoazo, diazo, triarylmPth~ne, xanthene, sulphonephthalein, acridul, quinoline, azine, oxazine, thi~7in~, anthraqui none, indigold, and the following individual compounds: AurantiaTM, Orasol orange RLNTM, Diamin green BTM, Direct green GTM, Fast red salt 3 GLTM, Fast blue salt BBTM, Fast Garnet salt GBCTM, Carta Yellow G 180 o/oTM, Murexide, Savinyl blue GLS, Irgalith blue GLSMv, Phthalocyanine and Alcannin, (2) mixtures of:
(a) one or more organic acids compounds, having a pK of less than about four, and (3) mixtures of (a) one or more organic acids having a pK of less than about 2 and (b) one or more acid dyes or acid in~ic~tors (4) mixtures of (a) one or more organic acid compounds having a pK of less than about 4 and (b) one or more members of the group I body of compounds, (5) mixtures of (a) one or more basic dyes or basic indicators and (b) one or more members of the group I body of compounds, (6) mixtures of (a) one or more dyes having a molecular structure cont~ining a lactone group, and (b) one or more acids having a pK of about 8 to about 12.
The compounds mentioned in group III are classified according to the Colour Index, 3rd Edition (1971), published by the Society of Dyers and Colourists, Great Britain and Conn's Biological Stains (9th Ed 1977).
Suitable monoazo dyes are: 4-(p-Ethoxyphenylazo)-m-phe-nylene-di~minf.
monohydrochloride, Orasol NavyBlueTM, Organol Orange, Janus GreenTM, Irgalith red P4R, Dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin Yellow R-, Eriochrome Black T, Chromotrope 2R, Ponceau 6R, yellow Orange STM, Brilliant Ponceau 5RTM, Chrysolidin GTM, Eriochrome black A, Benzyl orange, 10 Brilliant ponceau G/R/2RTM and chromolan yellow.
Suitable disazo dyes are: Fat red BSTM, Sudan Red BTM, Bismarck Brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast Pink 2 BLTM and Oil Red EGNTM.
Suitable triarylmethane dyes are: Methyl violet, Xylene cyanol FFTM, 15 ErioglaucineTM, Fuchsin NBTM, Fuchsin, Parafuchsin, Aurintri-carboxylic acid Ammonium salt, Patent Blue, Victoria blue RTM, Crystal violet and Irgalith Blue TNCTM .
Suitable xanthene dyes are: Phloxin B, Fluorescein sodium salt, Rhodamine B, Rhodamine B BaseTM, Rho~l~min~ 6GTM, Pyronin G, Irgalith Magenta TCBTM, 20 Irgalith Pink TYNCTM, Eosin ScarletTM, Eosin Yellowish, Erythrosin extra bluishTM, 4'5' Dibromofluorescein, Ethyl eosin, Gallein, PhloxineTM, Erythrosin yellowish BlendTM and Cyanosin BTM

The suitable sulphonephthaleins are cresol red, chorophenol red, chlorophenol blue, bromophenol blue, bromocresol purple and chlorocresol green.
The suitable acridine dyes are: Corisphosphine OTM, Acriflavine and acridine orange.
The most suitable quinoline dyes are: pinacyanol chloride, pinacyanol bromide, pinacyanol iodide, quinaldine red, cryptocyanine, 1, l '-Diethyl-2,2 -cyanine iodide, 2-(p-Dimethylamino-styryl)-l-ethyl-pyridinium iodide, 3,3 -Diethylthiadicarbocyanine iodide, ethyl red, Dicyanine A, Merocyanine 540 TM
and NeocyanineTM.
The suitable azine dyes are: Neutral red chloride, Neutral red iodide, NigrosineTM, Savinyl blue BTM, Orasol blue BLNTM, Safranin o TM, Azocarmin GTM, PhenosafranineTM, Azoc~rmin~ BXTM and Rhoduline violet.
The suitable oxazine dyes are: Solophenyl Brilliant Blue BLTM, Nile blue ATM, GallocyanineTM, G~ min~- BlueTM and Celestine blue.
The suitable dyes are: Methylene blue, Thinonin Toluidine Blue O, Methylene Green and Azure A/B/CTM.
The suitable anthraquinone dyes are: Savinyl Green BTM, Savinyl Blue RS, D+C Green 6TM, Blue VIF OrganolTM, Alizarin, Alizarin Cyanine 2RTM, Celliton Blue ExtraTM, Alizarin Blue STM, Nitro Fast Green GSB, Alizarin red S, Chin~1i7~rin, Oil Blue N, Solvay PurpleTM and Pu~ulinTM.
The suitable indigold dyes are: Ciba BlueTM, Indigo SyntheticTM, Chromophtal Bordeaux RSTM and Thioindigo red.

2 ~ 48554 Instead of one or more group I compounds, to be used in the composition of matter, mixtures can be employed.
The group of organic acidic compounds with a pK less than about four generally consists of organic acids and/or the halogenated sulfonphthaleins, which 5 are soluble in the selected solvent, when the latter is in the liquid state. Examples of these acids include oxalic acid, maleic acid, dichloroacetic acid, trichloroacetic acid, 2-naphthalene-sulphonic acid, chloroanilic acid, bromophenol blue, bromothymol blue, chlorophenol red, bromochlorophenol blue, bromocresol green, 3,4,5,6-tetrabromophenol-sulfonphthalein, bromophenol red, chlorocresol 10 green, chlorophenol blue, bromocresol purple and 2,4-dinitro-benzenesulphonic acld.
The group of basic dyes or basic indicators are generally the amino-triphenyl methanes, also known as the triaryl methanes, or their soluble salts, 8-hydroxyquinoline and the quinoline dyes, preferably the cyanines. Examples are:
15 basic fuchsin, pinacyanol iodide, pinacyanol chloride, pinacyanol bromide, 2-p-(dimethylaminostyryl)-1-ethyl-pyridinium iodide, crystal violet, cryptocyanine, dicyanine A, 3,3'-diethylthiacarbocyanine iodide, 1,1'-diethyl-2,2'-cyanineiodide, ethyl red, qllin~l(linP red, ethyl violet, brilliant green, pararos~nilinP, pararosaniline acetate, 8-hydroxy-quinoline, l-ethylpyridinium iodide and 5-(p-dimethylamino-20 benzilidine) rhodanine. Preferably the weight of the acid compounds is aboutthree or more times the weight of the basic compounds.

The above-mentioned pK values refer to the pK values as measured in water. Generally it is pler~ d that the pK of the acidic compound is lower than the corresponding pK value of the basic compound. Preferably the acid compounds have a pK value less than about four and the basic compounds have 5 a pK value less than about 5.
It should be noted that when the basic compound consists solely of one or more aminotriphenylmethanes or their soluble salts, the acid compound must be selected from the group con~i~ting of tetrahalogenated sulphonphthaleins and the other organic acids having a pK of less than about 2.
Preferred combinations of acidic compounds having a pK less than about 4 and basic dyes or basic indicators are bromophenol blue/basic fuchsin, chlorophenol blue/ethyl red and trichloracetic acid/3,3'-diethylthiadicarbocyanine iodide.
Mixtures of one or more organic acids having a pK less than about 2 and 15 one or more acid dyes or acid indicators, used in the composition of matter, changes color when the solvent passes from the solid into the liquid phase or reversed. In this combination the acid dyes used are preferably halogenated sulfonphthaleins .
Mixtures of one or more organic dyes, having a molecular structure 20 cont~inin~ a lactone group and one or more acids having a pK of about 8 to about 12, used in a solvent also change color when the solvent passes from the solid phase onto the liquid phase or reversed. In that combination the preferred compounds are crystal violet lactone and one or more of acids such as phenol, bisphenol A, pyrocathechol or 3 nitrophenol.
The compositions of matter most preferably comprise (a) a suitable inert 5 solvent as described above adapted to change from a solid state to a liquid state at substantially the predetermined temperature and (b) one or more organic moieties soluble in said solvent and adapted to change color upon the change in state of the solvent at substantially the pred~tellllhled temperature when so dissolved, and selected from:
10(1) one or more Group III compounds consisting of pinacyanol iodide, quinalidine red, l,l'-diethyl-2,2'cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, toluidin blue O, Orasol Orange RLNTM, Orasol Navy BlueTM, Irgalith Red PRTM, Fat Red BSTM, methyl violet, Xylene 15 Cyanol FFTM, Rhodamine BTM, Rhodamine 6GTM, Irgalith Magenta TCBTM, Irgalith Pink TYNCTM, Toluidin Blue OTM, Savinyl Green BTM, Savinyl Blue RSTM, yullJulill, 3,3'-diethylthia-dicarbocyanine iodide, cryptocyanine, Dicyanine A, merocyanine 540, 4-(p-ethoxyphenylazo)-m-phenylene ~ mine monohydro-' chloride, Yellow Orange STM, Chrysidan GTM, fuchsin, Aurintricarboxylic acid 20 (ammonium salt), Victoria Blue RTM, Pyronin GTM, gallein phloxine, Erythrosin Yellow BlendTM, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphospine OTM, acriflavine, acridine orange, rhoduline violet, Alizarin cyanin2RTM, Alizarin Red STM, alcannin, Aurantia, Direct Green GTM, Fast Red Salt 3GLTM, Fast Blue Salt BBTM, Fast Garnet Salt GBCTM, Carta Yellow G 180 o/oTM, murexide, Savinyl Blue GLSTM, Irgalith Blue GLSMTM, phthalocyanine, Di 5 Amingreen BTM, Alizarian Blue STM, Celliton Blue Extra, neocyanine, Janus GreenTM, dimethyl yellow, Fast YellowTM, methyl red sodium salt, Alizarin yellow RTM, Eriochrome black TTM, Chromotrope 2RTM, Ponceau 6RTM, Brilliant Ponceau G/R/2RTM, Chromolan yellow, Sudan Red BTM, Bismarck Brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast pink 2BLTM, Oil Red EGNTM, Euroglaucine, Fuchsin 10 NBTM, parafuchsin, Patent BlueTM, Irgalith Blue TNCTM, Phloxin BTM, fluorescein sodium salt, Rhodamine B baseTM, Eosinscarlet, Eosin YellowishTM, Eryth-rosin extra bluish, 4'5-dibromo fluorescein, ethyleosin, PhloxineTM, Cyanovin BTM, chlorocresol green, pinacyanol bromide, 2-p-dimethylamino-styryl)-1-1-ethyl pyridinium iodide, ethyl red, neutral red, iodide, nigrosine, Savinyl Blue BTM, 15 Orasol Blue BLNTM, Safranin OTM, Azocarnum GTM, Phenosafranine, Azoc~rmin~
BXTM, Solophenyl Brilliant Blue BLTM, Nile Blue ATM, gallocyanine, Gallamin~
blue, celestine blue, methylene green, Azure A/B/CTM, Blue VIF OrganolTM, Alizarin, Nitrofast Green GSBTM, qllin~li7arine, Oil Blue NTM, Solvay PurpleTM, Ciba BlueTM, Indigo SyntheticTM, Chromophtal Bordeaux RSTM, ThiorifolexTM, 20 Acid Alizarin Red BTM, 5-aminoflourescein, Rose BengalTM, Martius YellowTM, Chicago Blue 6BTM, Alcian Blue 8GXTM, cresyl violet, 4,4'Bis(dimethylamino) benzylhydrol, Zinc Pthalocyanine, Sudan IIITM, Pyronin yTM, Toluylene BlueTM, cresyl violet perchlorate, Mendola's BlueTM, Phosphine DyeTM, NitronTM, cresyl violet acetate, ceres orange RTM, 4-phenylazo-1-naphtyl-amine, 4-(4-Dimethylamino-l-naptylazo)-3-methoxybenzene sulfonic acid, Bindschedler's 5 GreenTM, and p-(p-dimethylamino-phenylazo)benzoic acid (herein-afterwards referred to as the Group III compounds or Group III organic moieties), or (2) a binary mixture of:
(A) one or more of a Group I body of compounds (hereinaflelwards referred to as the Group I compounds) consisting of (a) the organic acids, which 10 when inserted in the solvent system at conditions other than ~upelsa~ul~tion will yield a color change visible to the naked eye, and also have a pK of less than about four and (b) the halogenated sulfonphthaleins; and (B) one or more of a Group II body of compounds (hereinafterwards referred to as the Group II compounds) consisting of the aminotriphenylmethanes 15 and their soluble salts, 8-hydroxyquinoline, and the ~;yanilles, with the proviso that if no Group III compound is present and if the Group II compounds must be selected from one or more of the group consisting of consist solely of one or more aminotriphenylmethanes or their soluble salts, then the Group I compound must - be selected from one or more of the group consisting of oxalic acid, suitable 20 sulfonic acids and the tetrahalogenated sulfonphthaleins, and other organic acids having a pKl of about or less than 2.

2 1 4~554 Of course, the primary application of the instant invention is where the change in state of the composition of matter is induced by lenlpel~lure forces for use in a t~ll,pelature indicating device. By "suitable sulfonic acids" we mean sulfonic acids soluble in the selected solvent; these may be, for example, benzene 5 sulfonic acid, naphthalene sulfonic acid, toluene sulfonic acid, anthracene sulfonic acid, etc., depending on the solvent.
An inlele~Ling phenomena exhibited by the compositions is illustrated by the e~cample of a composition essentially consisting of pinacyanol iodide (at 0.035 weight percent) in ortho-bromonitrobenzene:ortho-chloronitrobenzene (75:25) 10 solvent. In the liquid phase this composition is blue, and in the solid phase appears rose/tan. However, if the composition is chilled to a very low temperature at a very high rate of cooling initially, the color of the solid appears purple. As the composition is allowed to warm to room temperature, the color changes from purple to rose/tan, requiring about 3-5 minutes for the color to become rose/tan.
15 (Similar phenomena have been observed with other compositions cont~ining other Group III moieties or other Group I plus Group III combinations~
Another example of an especially pl~felled Group I compound is chlorophenol red at a cunce~ tion of about 0.05 percent by mass. When dissolved in a solvent such as OCNB/OBNB, dibenzofurane, para-toluic acid and 20 other halogen nitrobenzenes, the liquid composition has a yellow color.
As enumerated above, in the absence of one or more Group III

compounds to be used for the organic moieties in the solvent system, one or more of a Group I body of compounds must be employed together with one or more of a Group II body of compounds. The Group I body of compounds generally consist of (a) the organic acids, which when inserted in the solvent system (at S conditions other than supe~salul~lion) will yield a color change visible to the naked eye, and have a pK of less than about four, and (b) the halogenated sulfonphthaleins which are soluble in the selected weakly polar or nonpolar aromatic solvent described below. Preferably, the Group I compound has a pK of between zero and three, and most preferably between about zero and about two.
10 Example of this Group I body of compounds include oxalic acid, naphtha-lenesulfonic acid, trichloroacetic acid, bromophenol blue, bromothymol blue, chlorophenol red, bromochlorophenol blue, bromocresol green, 3,4,5,6-tetra-bromophenol sulfonphthalein, bromophenol red, and chlorocresol green. Some compounds, such as maleic acid, will work if soluble in the predetermined solvent 15 system employed if the correct Group II compound is chosen.
These first groups of compounds, which are generally the halogenated sulfonphthaleins, are derivatives ofthe sulfonphthaleins inthe followingways:first the unsubstituted compounds are diprotic acid/base indicators, each having pK
values of (1) a pKl of about 2 and (2) a pK2 of about 7 to about 9. The 20 halogenated derivatives show only one pK which is much lower than the pK2 of the unsubstituted sulfonphthalein. Because there are halogen substituents on the sulfonphthalein molecule, it is our belief (while we do not limit the invention to the validity of our theory) that the pK value is reduced and the acid strength of the Group I is increased. As a consequence of this, the halogenated derivatives will respond in combination with one or more of the Group II compounds 5 enumerated below to produce the color reaction. For example, in a OCNB OBNB
solvent system and in combination with basic fuchsin (a Group II material), bromochlorophenol blue (a Group I material) gives a green color in the solid phase and a strikingly red color in the liquid phase. This is very similar to the color found when the bromophenol blue (a Group I compound) is combined with 10 basic fuchsin in the same ortho-chlolo~ obenzene: ortho-bromonitrobenzene solvent system.
The Group II compounds, which are generally the aminotriphenylmethanes, their soluble salts, 8-hydroxyquionline, and the ~;ya~ es, act in our opinion as constituents which perform a "dye" function. Of course, as indicated by the 15 dlsclosure above, a Group I compound may also act as a "dye"function. Examples of Group II compounds include ethyl red, crystal violet, pararos~niline (or "para Ros~nilinP Base"), pararosaniline acetate (or "para Ros~nilinP acetate"), basic fuchsin, 8-hydroxyquinoline, ethyl violet, brilliant green, pinacyanol chloride, and 3,3-diethylthiodicarbocyanine iodide. The Group I compounds are preferably 20 selected from the group consisting of bromophenol blue, bromochlorophenol blue, and bromothymol blue. One will notice that the second group of compounds generally consist of dyes which have basic nitrogen groups either as substituent amines or in heterocyclic rings. In general, the addition of one or more of the first group of compounds along with the second group of compounds to a solution of the previously described nonpolar or weakly polar aromatic solvent(s) such as 5 ortho-chloronitrobenzene and ortho-bromonitrobenzene solutions willprovide a color dirre~ ce between the solid and liquid phases of the aromatic solvent. It is preferred that the total weight of the Group I and Group II compounds be about 0.025 to about O.OS total weight percent of the entire weight of the composition of matter. It is advised that the melting point of the Group III or Group I and 10 Group II moieties be more than the melting point of the solvent system. It is preferred that the melting point of each of the Group I and Group II constituents be substantially more than the melting point of the solvent system selected, and it is much preferred that these Group I and Group II compounds melt at more than sixty degrees above the melting point of the solvent system. A basic 15 requirement is that at least one of the Group I and Group II compounds reflects or absorbs light in the visible area of the spectTum at or below the melting point of the solvent system or, in the alternative, at or above the melting point of the solvent system, or both, in different colors so that a change in color is visible to the naked eye. It is also prerelled that the Group I compounds weigh three or 20 more times the weight of the Group II compounds. While 0.05 weight percent of the total of the Group I and Group II compounds or Group III compound(s) is most preferred, any erÇecliv~ amount from the smallest for which the change in color is visible to the naked eye upon change in phases is satisfactory, and certainly no more than the solubility limits of the Group I and Group II
compounds (or Group III compound(s)) in the solvent system at the melting point 5 might also be affected. A supersaturated solution of Group I and Group II
compounds (or Group III compound(s)) in the solvent system, is not prerell~d, since Group I-III compounds are substantially more expensive than the solvent system constituents and an excess of them will be extravagant. Any pressure may be employed in making or in using the composition(s) of matter in a 10 temperature-indicating device so long as the solvent does not generate a substantial vapor in the application for the composition. If a Group III compound is not employed, it is p~erelled that the Group I compound have a lesser pKl and pK2 value than the corresponding pK values of the Group II compound.
Preferably, the Group II compound should have a pK1 value of less than about 15 5, and the Group I compound should have a pK1 of less than about 4.
As it will be appreciated by those skilled in the art having access to this disclosure, it is possible with the disclosure given above to combine almost any Group I compound indicated pK, which is soluble in the solvent system selected, (a solvent system of ortho-bromonitrobenzene: ortho-chloronillubenzene, for 20 example) and a complementary acid base material from Group II and generate practically any desired change in color. The considerations for those skilled in the art will be (1) the selection of Group III and/or Group I and Group II
compound(s) which yield a satisfactory change in predetermined colors; (2) that these compounds are soluble in the solvent system in the liquid state; (3) that the solvent system be properly dete~ led for the lempel~tule range desired; (4) that 5 the Group I and/or Group II compounds (or Group III compounds) be soluble in the desired system, and (5) if pertinent, that one compound of the Group I
compounds react as a strong acid against one or more of the Group II compounds in the solvent system.
As it will be recognized by those skilled in the art having access to this 10 disclosure, one may employ combinations of more than one Group III moiety, or a combinations of more than one Group III moiety, or a combination of a Group III moiety and a Group I moiety, or a combination of a Group II moiety and Group III moiety, or more than one Group I moiety with more than one Group II moiety to obtain color shifts generally not found in a single system, e.g., a mixture of pinacyanol iodide and qllin~l(linP red (two Group III compounds) yields a tan solid and deep dark purple liquid. There are some instances where two Group I compounds may be operable where one acts as an acid relative to the other e.g., (1) naphthalene sulfonic acid and one or more of (2) bromo-chlorophenol blue, chlorophenol blue, or bromocresol purple.
As an alternative to using one or more of the Group II compounds with one or more of the Group I compounds, one may select one of the aforesaid Group III compounds with (or preferably) in place of a combination of one or more Group I compounds and one or more Group II compounds. A caveat and proviso must be stated: in absence of a Group III compound one must employ one or more Group I compounds with one or more Group II compounds; if the 5 Group II compounds consist solely of one or more aminotriphenylmethanes or their soluble salts, then the Group I compound must be from one or more of the group consisting of oxalic acid, suitable sulfonic acids, tetrahalogenated sulfonphthaleins, and other soluble strong organic acids having a pKl of about or less than 2.
Another example of a Group I compound and a Group II compound is bromophenol blue and basic fuchsin. In the solid form, the basic fuchsin behaved as if it were at a very low pH and was in a form which has a green color between its pKl and pK2. This green color of basic fuchsin at very low pH is a little known fact, but can easily be demonstrated in any laboratory with common reagents. In 15 the liquid form, however, the bromophenol blue is yellow. The basic fuchsin was not in its first acid form and became red. Thus, the color of the liquid was red.
As will be appreciated by those in the art, generally the color of the liquid is the same or similar to the color of the Group II compound or Group III
compound when dissolved in the liquid phase of most of the suitable solvents 20 employed.
Similarly, crystal violet, which is a pH indicator having a pKl of ` ~ 21 48554 approximately 1, forms, in combination with oxalic acid and dissolved in the OCNB/OBNB solution, a blue liquid and a yellow solid.
It has also been found as well that (1) quinaldine red (a Group III
compound) which has a pK1 of approximately 1.6; (2) ethyl violet, which has a 5 pK1 of about 1.2; and (3) brilliant green, which has a pK1 of about 1.4, all react in solutions with naphthalenesulfonic acid to form different colored solid then liquid-phases.
As alternative to the above for Group I-Group II combinations, when the Group I material is other than a simple acid, and is a "dye" compound (such as 10 bromophenol blue), in addition to the Group I's behavior as an acid, there may be formed in the composition aggregates, mixed polymers, and the like, which cause what is referred to in the literature as "metachromism" or "metachromacy".
"Metachromacy" is that property of a substance which is expressed as a change in color (according to the wavelength of the light in which it is viewed) due to an 15 outside force. "Metachromacy" is mainly attributed to that color change phenomena when a dye is brought together with certain "tissue" molecules (macromolecules, e.g.,solid materials such as heparin, polysaccharides). Certain organic dyestuffs, however, are characterized by different colors when dissolved in inert solvents, which is described as "solvatochromism". See HACKH'S
20 CHEMICAL DICTIONARY 421 (4th Ed. 1969).
Once the organic moieties Group III compounds and/or Group I and `- 2 ~ 48554 Group II compounds are determined for the desired color change, they are added to a liquid mixture of the solvent constituents for the predetermined temperature and mixed, preferably by any suitable industrial mechanical mixing means known to those in the art, until a substantially complete dissolution has been obtained.
S After the solvent weight fractions have been determined and the composition of matter formed for each of the increment tempeldlules to be tested, a suitable ten~eldture-indicating device is constructed such as the device described below having a plurality of ~mpeld~ul~-sensitive regions, preferably having cavities in a heat-conductive carrier such as all-minllm wherein each composition of matter corresponding to one of the preselected points along the temperature curve fills one of the regions, preferably a cavity, in the heat conductive carrier device. A method and apparatus for depositing precisely metered quantities of a telllpeldture-sensitive composition of matter on a surface is taught by Pickett, et al, U.S. Pat. No. 3,810,779(1974), incorporated herein by reference, and the techniques of that patent are incorporated herein as much as copied verbatim. A preferable device for sealing a heat-sensitiv~ transparent cover sheet means in vacuum-sealing engagement with an allllllilllllll heat-conductivecarrier over cavities in the carrier is the Webb Model No. 2 machine m~mlf~stured by Bio-Medical Sciences, Inc., in Fairfield, New Jersey. The web machine embosses the heat con~lllcting carrier means, fillsthe embossed cavities with thermally responsive material utili7.ing the fill system disclosed in Picket et al. U.S. Patent No 3,810,779,and lays down a llansl)al~lll cover sheet in sealing engagement with the carrier means.
(2) Temperature-Indicating Device In FIG. 1, a temperature-indicator device is disclosed comprising a flat, gradually curved, or substantially curvilinear heat-conducting carrier means having one or more spaced cavities defined herein to determine a like number of predetermined lempeldlul~s in a temperature range by means of a like number of different thermally-responsive composition of matter. Each of the predetermined le~ el~tures is associated with a composition of matter that is substantially without illlpulilies, and may or may not be the compositions of matter stated above, but a composition of matter which does change from an opaqueform when solid to a transparent liquid upon melting. The telllpeldlule-indicating device comprises (1) a flat, gradually curved, or substantially curvilinear heat-conducting carrier with one or more cavities indented therein; (2) (in the absence of employing the compositions of matter of this invention) an indicator means located at the bottom of each of said cavities; (3) a lldn~l,alclll cover sheet means in sealing engagement with the carrier means above and overlying each of said cavities to form an enclosure between the wallsof the cavity and the transparent cover sheet means; and (4) a composition of matter which substantially fills the cavity and is adapted to change from a solid to a liquid at substantially the predetermined temperature associated with said cavity.
Referring to FIG. 1, one will notice that colorant 1 fills the bottom of a cavity "A" in a flat heat-con-lucting carrier means 2 of thickness 6, which means is substantially filled with a "classical" solid solution 5. The cavity "A" is covered 5 by a lla~ alelll cover sheet means 4 which fits in sealing engagement with heat-con~ cting carrier means 2 immediately surrounding cavity "A"and covering the solid solution 5 filling cavity "A".Within solid solution 5 is a substantially spherical cavity 3 which has a diameter 10 only slightly smaller than the width 12 of the cavity minus the small width 11 of the colorant 1. In the preferred 10 embodiment shown in FIG. 1, the carrier means cavity is in the shape of a trapezoid rotated around its axis, having a large diameter 8 at the top of the cavity and a smaller diameter 9 at the bottom of the cavity. The width 7 of the transpal~lll film 4 is preferably substantially equal to the width 6 of the heat-con~ cting carrier means 2. While the exact dimensions (6,7,8,9,11,12)of a 15 cavity in items such as those in FIG. 1 vary with the solvent system employed, the materials selected, and the composition of matter which is predetermined (whether or not one of the compositions of matter described above or a classical composition of matter which changes from opaque to transpalellt with change in phases from solid to liquid), it is well to describe a device employing ortho-20 chlorol~ilrobenzene and ortho-bromonitrobenzene recently constructed.
Referring again to FIG. 1, the heat con~ cting carrier means 2 is an alllmin-lm foil of thickness 6 of approximately 0.003 inches. The heat-con~ ctin~
carrier means 2 is preferably a material which as a high thermal conductivity and relatively large surface area of contact with the test subject and be of minilllulll thickness, while preserving its structural integrity, in order to permit rapid 5 conduction of heat into the cavity such as shown in FIG. 1. Where alllmin--m is used, its thickness may vary from about 0.001 inches to about 0.004 inches. In any event, the selection of such heat-conductive carrier means is well within the knowledge of those skilled in the art and needs no further elaboration. In a particularly effective embodiment, the heat-conducting carrier means may be 10 made of plastic. The carrier is provided with the n~cess~ry strength to serve as the main structural support, while at the same time providing rapid and uniform el~ture distribution throughout the thermometer device. As a consequence, the time required for taking ~elllpeldlure is substantially climini.~hed. The depth 12 of cavity "A" in FIG. 1 is selected to be preferably 0.004 inches, with the upper 15 horizontal width 9 being approximately 0.035 inches. The thickness 7 of the LldnspalellL film is approximately 0.001 inches, the letter being a painted letter on the bottom of the cavity "A". As implied in FIG. 1, a layer 1 of colorant material, e.g.,paint, is stamped onto the bottom of each cavity "A"of a visible material that may be sonlewllat absorbed into the composition of matter or solid solution 5 20 upon melting of the "classical" solid solution 5 to make the colorant material more visible. The transparent film cover means 4 may be poly~rol,ylene, Mylar (polyethylellel~lephth~l~te), nitrocellulose, polyvinyl chloride, etc. In FIG. 1, the transparent film cover means 4 is preferably a thermoplastic material and can be a coextruded film of Nylon 6{ (m~mlfa~tllred by the Allied Chemical Company) and Surlyn 1652{ (manufactured by E. I. duPont deNemours & Colnpally) which 5 film is produced by Pierson Industries Incorporated that is subsequently l~min~te~l to polypropylene by the Millprint Company of Milwaukee, Wisconsin.
In each cavity "A",such as that shown in FIG. 1, one of the predetermined compositions of matter that is associated with a predetermined melting point is poured into the cavity, filling approximately 60% of said cavity. After partial filling 10 of each cavity "A"with a particular composition of matter (here OCNB:OBNB) associated with a telllper~Lure to be measured (here between 96.0F. and 104.8 F.), transparent film 4 is put in sealing engagement with al~lminllm foil 2 through the use of machine such as the Webb Model No. 2 manufactured by BioMedical Sciences Inc. of Fairfield, New Jersey. As willbe recognized by those skilled in the 15 an, small deviations could be made in ratios of the dimensions 6 through 12, or alL~Illa~ ely, the ratios could be m~int~inPcl for dirreLelll sized systems (e.g.,by multiplying distances 6 through 12 by a uniform but different constant) without subst~nti~lly affecting the results of the invention.
FIG. 2 presents a partial plan view from above and the side of one 20 embodiment of the prior art thermometer of the '552 patent showing a heat con(l-lcting carrier means, "C", of a thermometer in a Celsius scale. In a particularly effective embodiment of this clinical thermometer, a rectangular grid is formed wherein each cavity 13 employs a construction as in FIG. 1 and is clearly associated with a temperature to be determined within the range to be tested through m~rking~ located on the side of the grid.
In FIGS. 3A and 3B, another embodiment of the prior art thermometer is 5 disclosed for measuring telllpela~ules at 0.2 F. incl~lllellls from 96.0 F. to 104.8 F., combining the compositions of matter of the '552 patent (preferably OCNB:OBNB/pinacyanol iodide) with the cavities of FIG. 1.
FIG. 3A displays a plan view of the substantially flat oral tenlpelaLule indicting device as seen from above. Again, the thermometer has an alllmimlm 10 heat conducting carrier means 44 (of thickness 47 in FIG. 3B) which acts not only as a main structural body of support, but at the same time provides rapid and ullirollll temperature distribution throughout the spatula portion "F"(having width 54 cont~ining grid "G" of a plurality of cavities (each of diameter 57 and spaced center-to center with each neighbor along a horizontal "x"axis or vertical "y"axis in FIG. 3A at a distance 52 apart) of FIG. 1, each cavity with the composition of matter and each associated with a pred~le.lllilled l~lllpel~lule to be measured at 0.2 F. increments from 96.0 F. to 104.8 F. "Spatula" portion "F" of the device of FIG. 3A is rounded for safety so that some distance, 56,is m~int~in~l between the most forward row of cavities and the edge of the device. It may be observed 20 by those skilled in the art that if "classical"compositions of matter are employed in lieu of our compositions of matter, that each cavity will n~.cess~ry employ an indicator layer such as layer 1 of FIG. 1. It will be evident to those skilled in the art having access to this disclosure that an indicator layer is not required when the thermally responsive material is a solvent in combination with the organic moieties of Hof et al. '552.
Again in FIG. 3A, one willnote that the alllmimlm heat conducting carrier means is covered above for the entire handle E" portion of the thermometer device by a top plastic layer 42 of width 54, preferable made out of a plastic such as poly~lyl~;ne, polypropylene, or polyethylene.
Also in FIG. 3A, it will be recognized that the handle "E" has been stamped from below so as to make the device realize two ridges, ribs, or abutments 41a that protrude from above the carrier means 44 by some nominal tli~t~nre which is approximately the same as width 47 of carrier means 44;
likewise, the device realizes two cavities 41b in carrier means 44 that parallel the ridges 41a. As will be appreciated by those skilled in the art, although the distances shown in FIGS. 3A and 3B can be readily adjusted with respect to one another or in proportion (widths 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, and 58 can be multiplied by different cons~lll~) it is well to describe a device for measuring human temperatures in the range of 96.0 F. to 104.8 F. that we recently constructed, employing ortho-chloronitro-benzene and ortho-bromonitrobenzene in a solvent system with pinacyanol iodide in the amount of 0.035% by weight to form a thermometer with the compositions of matter of this invention, which is the best mode of our invention and which is marketed by PyMaH Corporation (Somerville, New Jersey) under the trademark TEMPA DOT READY STRIP(~3). Refer ring again to LFIG. 3A, the thermometer has a width 54 of about 0.345 inches at the widest portion of handle "E" and has 5 the same width 54 of about 0.345 inches at the widest portion of handle "E" and has the same width 54 of about 0.345 inches in the spatula portion "F" of the thermometer. The cavities each have a diameter 57 of about 0.039 inches and each cavity has a depth of about 0.005 inches, and is spaced from each neighbor on a horizontal "x"axis or vertical "y"axis by a ~ t~nre 52 of 0.015 inches. The 10 top and bottom rows of cavities are of a distance 55 of about 0.039 inches from the leading edges, respectively, of the thermometer, and have a center line on the right-hand column which is a distance 56 of a~out 0.193 inches from the tip of the rounded edge of the spatula "G" portion of the thermometer. In FIG. 3B, taken along line 13--13 of FIG. 3A, it will be appreciated that the oral thermometer 15 device has an overall length of 4.250 inches, and consists of an all~,,,i,,,l,,, heat conducting carrier means 44 having an overall length of 4.250 inches and a depth 47 of about 0.003 inches. The alllmimlm head con(l~lcting carrier means 44 is covered on the handle portion "E" of the thermometer by a poly~ropylene or poly~lylelle layer of thickness 48 of about 0.003 inches; the carrier means also is 20 in engagement with a poly~lupylene or poly~lylel1e bottom plate mean 46 of width 49 of about 0.003 inches that traverses the entire length of the thermometer. Two bands of thermoplastic material (coextruded film of Nylon 6TM and Surlyn 652TM
subsequently l~min~t~1 to polypropylene) cover the two sub-grids (100 F. to 104.8F.and 96.0F. to 99.8F.) and are each of width 51 of approximately 0.300 inches along the "x"axis and of depth 50 of from about 0.003 to about 0.005 5 inches.
FIG. 4 depicts a cross-sectional view of the disposable thermometer of the prior art showing cavities in which are held the lelllpelaluie indicating system, 69.
The heat conducting material, 67, is covered by a transparent layer, 66, by a polyisobutylene adhesive layer, 68.
The indicating system of the instant invention comprises a thermally sensitive material dispersed in a matrix forming material. The matrix forming material is an amorphous organic natural or synthetic polymeric material in which the thermally sensitive material is insoluble at the predetermined l~mpel~ture at which it forms a liquid phase, and with respect to which it is inert. Any thermally sensitive material of the prior art may be utilized provided that it meets the above criteria with respect to the matrix forming material. The prefelled thermally sensitive materials are the OCNB and OBNB of Hof et al '552 patent. More preferably the organic moiety of Hof et al '552 is utilized in conjunction with the OCNB and OBNB.
Illustrative non-limhing examples of matrix forming materials useful in the practice of this invention are polyisobutylene, low density polyethylene, amorphous poly~ro~ylene and microcrystalline waxes. The plefellcd matrix forming material is polyisobutylene. In its plerell~d form the matrix forming material has a number average molecular weight of about 2,500 to about 400,000; e.g.,about 2,500 to about 75,000. The ParapolTM polyisobutylene typically has a viscosity of 5 about 3,000 cs. to about 4400 cs. at 100 C, e.g. ,3,500 to 4400 cs. Parapol 2500 has a typical number average molecular weight of about 2500 which corresponds to a viscosity of 4400 cs. at 100 C. The temperature sensing composition of this invention comprises about 50 to about 75 weight percent of matrix forming material and about 25 to about 50 weight percent of a thermally responsive 10 material. Where the thermally responsive material contains other compounds such as dyes, organic moieties of Hof '552, nucleating agents etc., the weight percent of thermally responsive material includes such other compounds.
Preferably the matrix forming material comprises about 60 to about 70 weight percent of the lellll?el~Lul~ sensing composition.
In a plerelled embodiment the OCNB and OBNB of Hof et al, in combination with the organic moieties disclosed therein are utilized as the thermally responsive material. As is described by Hof et al a different composition of the solid solution is utilized for each temperature to be monitored.
For a clinical thermometer this will generally cover the range of 96.0 F. to about 20 104.8 F. The thermally responsive material of Hof et al. '552 (OCNB/OBNB) together with any other compounds is referred to as "TRM."

2 1 4~554 While a nucleating agent is not required in the practice of this invention its incorporation into the le~Ilpeldture sensing composition is pIerell~d since it reduces the time for reversal of the thermometer to ItS unfired state to about 3-4 minl-t~s. Where the TRM comprises the thermally responsive materials of Hof 5 et al., the preferred nucleating agent is anthraquinone. Preferable the anthraquinone is dispersed into a quantity of matrix forming material.
Components utilized in an illustrative example and the procedure for preparation are described in the example below.
EXAMPLE
A thermometer was prepared utiIi7.ing the thermally responsive solid solution of Hof, et al. together with pinacyanol iodide as the organic material.
The following formulation was utilized.
Component % by weight Polyisobutylene (Exxon Parapol 2500) 60.0 TRM 33.3 9,10- Anthraquinone in Parapol 2500 6.7 Premix (2.5 wt. %) The following method of pr~paIdlion was utilized:
1. The polyisobutylene and TRM are heated to about 120 F.
20 2. The TRM is dispersed in the polyisobutylene using mechanical mixing.
3. Continue mixing while the composition is cooled to room temperature and all of the TRM has solidified and been dispersed into the polyisobutylene.

4. Add the 9,10-anthraquinone premix to the cooled blend and disperse by mechanical mixing.
The above described lelllpelalule sensitive composition is utilized in preparing a clinical thermometer. The thermometers are held in a water bath 5 m~int~ined at the temperature to be tested for a time sufficient to completely melt the temperature sensing composition. Reading stability of about 30 minutes is achieved at room temperature. The reading stability time and reversal time can be controlled by altering the quantity of nucleating agent utilized. Instead of using a premix, by dispersing about 1% by weight anthraquinone into the PIB/TRM
10 dispersion, the retention time of the stable reading is reduced to 30 seconds and the time for complete reversal of the thermometer is about 10 minutes at room l~lllpelal~llt; .
In another embodiment, the TRM is ground to reduce its particle size to about 80 to about 100 mesh (U.S. Sieve Series). The TRM is the uniformly 15 dispersed into the matrix material by mechanical mixing at a temperature below the melting pint of the TRM. The nucleating agent, or preferably the nucleating agent premix, is then added to the TRM in matrix material dispersion and mixed at a tenlpelalure below the melting point of the TRM until the nucleating agent is uniformly dispersed. The matrix forming material, e.g. ,polyisobutylene, cannot 20 be a solvent for the TRM, the dye dispersed in the TRM, or for the nucleating agent. Furthermore, it must be nonvolatile and not be soluble in the TRM.

`- 21 48554 It will be appreciated by those skilled in the art having access to this disclosure that any combination of TRM and matrix forming material which meet the required criteria can be used to prepared the thermometers of this invention.
For taking the temperature of children, the thermometer can be used either as an 5 axillary or rectal thermometer with ap~rop.iate adjustment of calibration to compensate for the difference in temperature indicated at such location other than the mouth as compared to body core lelllpelaLule.
The term "temperature sensitive composition" as used in the specification and claims means the combination of the matrix forming material and the 10 thermally responsive material, and optionally, an indicator such as a dye or the organic moieties of Hof et al. '552. The term "temperature responsive material"
(TRM) as used in the specification and claims means a normally solid compound or mixtures of compounds which is subject to a change of state from a solid to a liquid at a predetermined l~lllpeldture within the temperature range to be 15 monitored. The TRM must be susceptible to supercooling after it has changed from the solid to liquid state for at least a few minutes, generally several hours and as much as 24 hours.
In another embodiment of the invention the TRM is emulsified into the polyisobutylene utilizing a dispersing or emulsifying agent to assist in reducing the 20 particle size of the TRM.
Not wishing to be bound by theory, it is believed that the small particle size -- 21 4~554 results in greater stability of the composition from the standpoint of settling out or coalescence of the TRM.
The prerelled emulsifying agent is a C14 to C24 saturated alcohol; more preferably C16 to C22. Since the thermometers of this invention are to be used 5 orally the dispel~ g or emulsifying agent of choice is cetyl alcohol because it is readily available as USP/NF grade. Other grades do not present a toxicity problem. However, utili7ing a USP/NF grade avoids any question as to the compounds safety.
In this embodiment of the invention the polyisobutylene (PIB) to TRM
10 ratio,byweight,isabout 90/lOtoabout 66/34;e.g.about 80/20toabout 75/25.
The nucleating agent used in this composition is 9,10 Anthraqinone utilized at about 0.01to about 0.10weightpercent. The salul~d alcohol isutilized at about 7 ppm to about 60 ppm; e.g.,about 8 ppm to about 50 ppm.
A typical formulation for preparing the improved composition of this invention is shown below.
Component Quantity Parapol 2500 (PIB) 75.15%
TRM 24.75%
9,10 Anthraquinone 0.099 %
Cetyl Alcohol 8 ppm The cetyl alcohol is dissolved into the TR~ prior to the emulsification step.

A premix of the anthraquinone is prepared by mixing it with a minor amount of the Parapol 2500.
The premix can comprise about 75 parts PIB to about 25 parts of anthraquinone to about 95 parts PIB to about 5 Parts anthraquinone. Typically, 5 the premix composition willcomprise about 80/20to about 90/lOparts of PIB to anthraquinone; preferably about 90/10 parts of PIB to anthraquinone by weight.
The emulsification step is carried out utili7.ing a high shear mixer.
The TRM is liquefied by heating and added to the Parapol 2500 and mixed in the high shear mixer for a time sufficient to fully emulsify the two components.
10 The blend is subsequently cooled while mixing continuously. It has been found that generally, a mixing time of about 5 to about 10 minutes is sufficient to fully emulsify the compositions. After the emulsification step is completed the anthraquinone premix is added to the blend and mixing is contimle~l for about S
to about 10 minutes.
It will be appreciated by those skilled in the art having access to this disclosure that mixing times will be a function of the high shear mixer selected as well as the batch size.
Mixing times are readily determined without undue experimentation. In carrying out the emulsification step a ROSS planetary mixer (a one quart model 20 LDM) was utilized. Initially, hot water at 140 F was run through the jacket of themixer. Asmixingcontinued watertemperature wasdecreased tom~int~in the 2 i 48554 batch temperature at about 140F. Subsequently, after mixing was completed, cold water was run through the jacket to cool the mixture to about 40 F to solidify the TRM. After warming the mixture to room temperature the anthraquinone premix comprising 90 parts PIB to 10 parts of anthraquinone was 5 added in an amount suf~lcient to bring the anthraquinone concentration in the TRM/PIB blend to about 0.099% by weight, and mixing continued for about 10 mim-tes. The batch size utilized in the Model LDM blender was about 300 grams.
After preparation of the emulsified TRM/Parapol mixture the composition is passed through a 100 mesh screen to elimin~te any particles of TRM which are 10 greater than 0.004 inches.
Surprisingly, the compositions of the reversible thermometer of this invention respond to more tel,lpel~L~lre rapidly to reach an equilibrium tenlpel~lule reading as compared to the prior art thermometers of Hof '552 described above.
While the process is described as an emulsification process, it will be appreciated by those skilled in the art that the resulting product has a TRM
dispersed into a matrix forming material which is insoluble in the TRM. Hence the composition of matter is substantially the same as that described above except that the particle size of the TRM has been reduced by lltili7.ing the emulsification 20 process.

Claims (43)

1. A composition of matter suitable for use in a reversible thermometer comprising:
(a) a thermally responsive material capable of being supercooled at least for several minutes, and subject to a change in state from a solid to a liquid substantially at a predetermined temperature;
(b) means for visually observing the change in state; and (c) a matrix forming material comprising an amorphous organic compound, the matrix forming material being insoluble in the thermally responsive material; whereby the thermally responsive material is dispersed within the matrix forming material, the composition of matter being reversibly responsive to changes in temperature, and remaining in the liquid state for a time sufficient to permit a user of the composition to observe the change in state.

2. The composition of matter according to claim 1 wherein the matrix forming material is a polyisobutylene, low density polyethylene, amorphous polypropylene or mixtures thereof.

3. The composition of matter according to claim 1 wherein the matrix forming material is polyisobutylene.

4. The composition of matter according to claim 1 wherein the thermally responsive material together with the means for visually observing the change in state thereof exhibits a sharp color change upon transition from a liquid state to a solid state or from a solid state to a liquid state, the thermally responsive material together with the means for visually observing the change in state comprising:
(a) a solvent, said solvent being a temperature responsive composition forming a solid solution in the solid state and adapted to change from a solid to a liquid state substantially at a predetermined temperature; and (b) an effective amount of at least one organic moiety dissolved in and inert towards said solvent being adapted to change the color of the composition visible to the naked eye upon the change in state at substantially the predetermined temperature when so dissolved, said organic moiety being selected from one of the groups consisting essentially of:
(1) at least one of a Group III body of compounds consisting of pinacyanol iodide, quinaldine red, 1,1'-diethyl-2,2'-cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, Toluidin Blue OTM, Orasol Orange RLNTM, Orasol Navy BlueTM, Irgalith Red PRTM, Fat Red BSTM, methyl violet, Xylene Cyanol FFTM, Rhodamine 6GTM, Rhodanine BTM, Irgalith Magenta TCBTM, irgalite pink TYNCTM, Toluidine Blue O, Savinyl Green BTM, Savinyl Blue RSTM, purpurin 3,3'-diethylthiadicarbocyanine iodide, cryptocyanine, Dicyanine ATM, Merocyanine 540TM, 4-(p-ethoxypheny-lazo)-m-phenylene diamine monohydrochloride, Yellow Orange STM, Chrysoidin GTM, fuchsin, aurintricarboxylic acid (ammonium salt), Victoria Blue RTM, Pyronin GTM, gallein, phloxine, Erythrosin Yellow BlendTM, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphosphine OTM, acriflavine, acridine orange, rhoduline violet, Alizarin Cyanin 2RTM, Alizarin Red STM, alcannin, Aurantia, Direct Green GTM, Fast Red Salt 3GLTM, Fast Blue Salt BBTM, Fast Garnet Salt GBCTM, Carta Yellow G 180 o/oTM, murexide, Savinyl Blue GLSTM, Irgalith Blue GLSMTM, phthalo-cyanine, Di Amingreen BTM, Alizarin Blue S, Celliton Blue ExtraTM, neocyanine, Janus Green, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow RTM, Eriochrome Black TTM, Chromotrope 2RTM, Ponceau 6RTM, Brilliant Ponceau G/R/2RTM, chromolan yellow, Sudan Red BTM, Bismarck brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast pink 2BLTM, Oil Red EGNTM, Euroglaucine, Fuchsin NBTM, parafuchsin, Patent BlueTM, Irgalith Blue TNCTM, Phioxin BTM, fluorescein sodium salt, Rhodamine B baseTM, Eosin Scarlet, Esoin YellowishTM, Ery throsin extra bluish, 4,5-dibromo-flucorescein, ethyleosin, PhloxineTM, Cyanovin BTM, chlorocresol green, pinacyanol bromide, 2-(p-dime-thylaminostyryl)-1-ethylpryidinium iodide ethyl red, neutral red iodide, nigrosine, savinyl blue BTM, Orasol Blue BLNTM, Safranin OTM, Azocarnun GTM, Pheno-safranine, Azocarmine BXTM, Solophenyl Brilliant Blue BLTM, Nile Blue ATM, gallocyanine, gallamine blue, celestine blue, methylene green, Azure A/B/CTM, Blue VIF OrganolTM, Alizarin, Nitrofast Green GSBTM, quinalizarine, Oil Blue NTM, Solvay purple, Ciba BlueTM, Indigo syntheticTM, Chromophtal Bordeaux RSTM, ThiorifolexTM, Acid Alizarin Red BTM, 5-Amino flourescein, Rose BengalTM, Martius YellowTM, Chicago Blue 6BTM, Alcian Blue 8GXTM, Cresyl violet, 4,4' Bis(dimethylamino)-benzylhdrol, Zinc Pthalocyanine, Sudan IIITM, Pyronin YTM, Toluylene BlueTM, cresyl violet perchlorate, Mendola's BlueTM, Phosphine Dye, NitronTM, cresyl violet acetate, Ceres Orange RTM, 4-phenylazo- 1-naphtylamine, 4-(4-Dimethylamino- 1 -napthylazo) -3-methoxybenzene sulfonic acid, Bind-schedler's GreenTM, and p-(p-dimethylaminophenylazo) benzoic acid;
(2) a binary mixture of:
(A) at least one of a Group I body of compounds soluble in said solvent consisting of the halogenated sulfonphthaleins and the organic acids having a pK1 of less than or about four; and (B) at least one of a Group II body of compounds consisting of the aminotriphenylmethane and their soluble salts, 8-hydroxyquinoline, and the cyanines; with the proviso that if the Group II compounds consist solely of at least one aminotriphenylmethanes or their soluble salts, then the Group I compound must be selected from at least one of the group consisting of oxalic acid, suitable soluble sulfonic acids and the tetrahalogenated sulfonphthaleins, and the other soluble organic acids having a pK1 of less than or about 2, and wherein the weight ratio of the Group I body of compounds to the Group II body of compounds is more than or about 3 to 1; and (3) at least one of the aforesaid Group III body of compounds with at least one of the Group I or Group II bodies of compounds.

5. The composition according to claim 4 wherein the solvent is a weakly polar or non-polar aromatic compound comprising one or more of o-chloronitrobenzene, o-bromonitrobenzene, meta-iodonitrobenzene, para-iodonitrobenzene and paratoluic acid.

6. The composition according to claim 4 wherein the solvent is a solid solution of o-chloronitrobenzene and o-bromonitrobenzene.

7. The composition according to claim 4 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol red dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

8. The composition according to claim 4 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromocresolpurple dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

9. The composition according to claim 4 wherein the organic moiety is an effective amount of pinacyanol iodide dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

10. The composition according to claim 4 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol blue dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

11. A temperature indicating device comprising a heat conducting carrier having a multiplicity of spaced region defined therein to determine a like number of predetermined temperature in a predetermined temperature range, said spaced regions containing a like number of different compositions of matter therein, said carrier having a transparent cover sheet means in sealing engagement therewith, said compositions of matter comprising:
(a) a thermally responsive material capable of being supercooled at least for several minutes, and subject to a change in state from a solid to a liquid substantially at a predetermined temperature;
(b) means for visually observing the change in state; and (c) a matrix forming material comprising an amorphous organic compound, the matrix forming material being insoluble in the thermally responsive material; wherein the thermally responsive material is dispersed within the matrix forming material, the composition of matter being reversibly responsive to changes in temperature, and remaining in the liquid state for a time sufficient to permit a user of the composition to observe the change in state.

12. The temperature indicating device according to claim 11 wherein the matrix forming material is a polyisobutylene, low density polyethylene, amorphous polyplopylene or mixtures thereof.

13. The temperature indicating device according to claim 11 wherein the matrix forming material is polyisobutylene.

14. The temperature indicating device according to claim 11 wherein the thermally responsive material together with the means for visually observing the change in state thereof exhibits a sharp color change upon transition from a liquid state to a solid state or from a solid state to a liquid state, the thermally responsive material together with the means for visually observing the change in state comprising:
(a) a solvent, said solvent being a temperature responsive composition forming a solid solution in the solid state and adapted to change from a solid to a liquid state substantially at a predetermined temperature; and (b) an effective amount of at least one organic moiety dissolved in and inert towards said solvent being adapted to change the color of the composition visible to the naked eye upon the change in state at substantially the predetermined temperature when so dissolved, said organic moiety being selected from one of the groups consisting essentially of:
(1) at least one of a Group III body of compounds consisting of pinacyanol iodide, quinaldine red, 1,1'-diethyl-2,2'-cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, Toluidin Blue OTM, Orasol Orange RLNTM, Orasol Navy BlueTM, Irgalith Red PRTM, Fat Red BSTM, methyl violet, Xylene Cyanol FFTM, Rhodamine 6GTM, Rhodanine BTM, Irgalith Magenta TCBTM, irgalite pink TYNCTM, Toluidine Blue O, Savinyl Green BTM, Savinyl Blue RSTM, purpurin 3,3'-diethylthiadicarbocya nine iodide, cryptocyanine, Dicyanine ATM, Merocyanine 540TM, 4-(p-ethoxyphenylazo)-m-phenylene diamine monohydrochlo ride, Yellow Orange STM, Chrysoidin GTM, fuchsin, aurintri carboxylic acid (ammonium salt), Victoria Blue RTM, Pyronin GTM, gallein, phloxine, Erythrosin Yellow BlendTM, chlorophe-nol blue, bromophenol blue, bromocresol purple, Coriphos- phine OTM, acriflavine, acridine orange, rhoduline violet, Alizarin Cyanin 2RTM, Alizarin Red STM, alcannin, Aurantia, Direct Green GTM, Fast Red Salt 3GLTM, Fast Blue Salt BBTM, Fast Garnet Salt GBCTM, Carta Yellow G 180 o/oTM, murexide, Savinyl Blue GLSTM, Irgalith Blue GLSMTM, phthalocyanine, Di Amingreen BTM, Alizarin Blue S, Celliton Blue ExtraTM, neo- cyanine, Janus Green, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow RTM, Eriochrome Black TTM, Chromotrope 2RTM, Ponceau 6RTM, Brilliant Ponceau G/R/2RTM, chromolan yellow, Sudan Red BTM, Bismarck brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast pink 2BLTM, Oil Red EGNTM, Euroglaucine, Fuchsin NBTM, parafuchsin, Patent BlueTM, Irgalith Blue TNCTM, Phloxin BTM, fluorescein sodium salt, Rhodamine B baseTM, Eosin Scarlet, Esoin YellowishTM, Ery- throsin extra bluish, 4,5-dibromoflucorescein, ethyleosin, PhloxineTM, Cyanovin BTM, chlorocresol green, pinacyanol bromide, 2-(p-dimethylaminostyryl)-1-ethyl pryidinium iodide ethyl red, neutral red iodide, nigrosine, savinyl blue BTM, Orasol Blue BLNTM, Safranin OTM, Azocarnun GTM, Phenosafranine, Azocarmine BXTM, Solophenyl Brilliant Blue BLTM, Nile Blue ATM, gallocyanine, gallamine blue, celestine blue, methylene green, Azure A/B/CTM, Blue VIF
OrganolTM, Alizarin, Nitrofast Green GSBTM, quinalizarine, Oil Blue NTM, olvay purple, Ciba BlueTM, Indigo syntheticTM, Chromophtal Bordeaux RSTM, ThiorifolexTM, Acid Alizarin Red BTM, 5-Amino flourescein, Rose BengalTM, Martius YellowTM, Chicago Blue 6BTM, Alcian Blue 8GXTM, Cresyl violet, 4,4'Bis(dimethylami- no)-benzylhdrol, Zinc Pthalocyanine, Sudan IIITM, Pyronin YTM, Toluylene BlueTM, cresyl violet perchlorate, Mendola's BlueTM, Phosphine Dye, NitronTM, cresyl violet acetate, Ceres Orange RTM, 4-phenylazo-1-naphtylamine, 4-(4-Dimethylamino-1-napthylazo)-3-methoxybenzene sulfonic acid, Bind-schedler's GreenTM, and p-(p-dimethylaminophenylazo) benzoic acid;
(2) a binary mixture of:
(A) at least one of a Group I body of compounds soluble in said solvent consisting of the halogenated sulfonphthaleins and the organic acids having a pK1 of less than or about four; and (B) at least one of a Group II body of compounds consisting of the aminotriphenylmethane and their soluble salts, 8-hydroxyquinoline, and the cyanines; with the proviso that if the Group II compounds consist solely of at least one aminotriphenyl-methanes or their soluble salts, then the Group I compound must be selected from at least one of the group consisting of oxalic acid, suitable soluble sulfonic acids and the tetrahalogenated sulfon-phthaleins, and the other soluble organic acids having a pK1 of less than or about 2, and wherein the weight ratio of the Group I body of compounds to the Group II body of compounds is more than or about 3 to 1; and (3) at least one of the aforesaid Group III body of compounds with at least one of the Group I or Group II bodies of compounds.

15. The temperature indicating device according to claim 14 wherein the solvent is a weakly polar or non-polar aromatic compound comprising one or more of o-chloronitrobenzene, o-bromonitrobenzene, meta-iodonitrobenzene, para-iodoni-trobenzene and para-toluic acid.

16. The temperature indicating device according to claim 14 wherein the solvent is a solid solution of o-chloronitrobenzene and o-bromonitrobenzene.

17. The temperature indicating device according to claim 14 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol red dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

18. The temperature indicating device according to claim 14 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromocresolpurple dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

19. The temperature indicating device according to claim 14 wherein the organic moiety is an effective amount of pinacyanol iodide dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

20. The temperature indicating device according to claim 14 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol blue dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

21. The composition of matter according to claim 1 wherein a minor amount of a nucleating agent is included, thereby reducing the time required for the composition to revert to the solid state after being removed from a heat source which caused the thermally responsive material to undergo a change in state.

22. The composition of matter according to claim 4 wherein a minor amount of a nucleating agent is included, thereby reducing the time required for the composition to revert to the solid state after being removed from a heat source which caused the thermally responsive material to undergo a change in state.

23. The composition of matter according to claim 22 wherein the solvent is a solid solution of o-chloronitrobenzene and o-bromo-nitrobenzene and the nucleating agent is anthraquinone.

24. The temperature indicating device according to claim 11 wherein a minor amount of nucleating agent is included, thereby reducing the time required for the composition to revert to the solid state after being removed from a heat source which caused the thermally responsive material to undergo a change in state.

25. The temperature indicating device according to claim 14 wherein a minor amount of nucleating agent is included, thereby reducing the time required for the composition to revert to the solid state after being removed from a heat source which caused the thermally responsive material to undergo a change in state.

26. The temperature indicating device according to claim 25 wherein the solvent is a solid solution of o-chloronitrobenzene and o-bromonitrobenzene and the nucleating agent is anthraquinone.

27. A process for preparing a composition of matter suitable for use in a reversible thermometer, the composition of matter comprising:
(a) a thermally responsive material capable of being supercooled at least for several minutes, and subject to a change in state from a solid to a liquid substantially at a predetermined temperature;
(b) means for visually observing the change in state; and (c) a matrix forming material comprising an amorphous organic compound, the matrix forming material being insoluble in the thermally responsive material; whereby the thermally responsive material isdispersed within the matrix forming material, the composition of matter being reversibly responsive to changes in temperature, and remaining in the liquid state for a time sufficient to permit a user of the composition to observe the change in state; the thermally responsive material being dispersed into the matrix forming material by the process steps comprising:
(d) converting the thermally responsive material to a liquid by heating it above the predetermined temperature;
(e) emulsifying the thermally responsive material into the matrix forming material by mechanical shearing, thereby forming an emulsion of thermally responsive material in the matrix forming material; and (f) cooling the the mixture of thermally responsive material and matrix forming material sufficiently to solidify the thermally responsive material;

28. The process according to claim 27 wherein an emulsifier is included in the thermally responsive material.

29. The process according to claim 28 wherein the emulsifier is a C14 to C24 saturated alcohol.

30. The process according to claim 28 wherein the emulsifier is a C16 to C22 saturated alcohol.

31. The process according to claim 28 wherein the emulsifier is cetyl alcohol.

32. The process according to claim 27 wherein a nucleating agent is added to the mixture of matrix forming material and thermally responsive material.

33. The process according to claim 27 wherein the matrix forming material is a polyisobutylene, low density polyethylene, amorphous polypropylene or mixtures thereof.

34. The process according to claim 27 wherein the matrix forming material is polyisobutylene .

35. The process according to claim 27 wherein the thermally responsive material together with the means for visually observing the change in state thereof exhibits a sharp color change upon transition from a liquid state to a solid state or from a solid state to a liquid state, the thermally responsive material together with the means for visually observing the change in state comprising:
(a) a solvent, said solvent being a temperature responsive composition forming a solid solution in the solid state and adapted to change from a solid to a liquid state substantially at a predetermined temperature; and (b) an effective amount of at least one organic moiety dissolved in and inert towards said solvent being adapted to change the color of the composition visible to the naked eye upon the change in state at substantially the predetermined temperature when so dissolved, said organic moiety being selected from one of the groups consisting essentially of:

(1) at least one of a Group III body of compounds consisting of pinacyanol iodide, quinaldine red, 1,1'-diethyl-2,2'-cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red odide, neutral red chloride, crystal violet, acridin orange, Toluidin Blue OTM, Orasol Orange RLNTM, Orasol Navy BlueTM, Irgalith Red PRTM, Fat Red BSTM, methyl violet, Xylene Cyanol FFTM, Rhodamine 6GTM, Rhodanine BTM, Irgalith Magenta TCBTM, irgalite pink TYNCTM, Toluidine Blue O, Savinyl Green BTM, Savinyl Blue RSTM, purpurin 3,3'-diethylthiadicarbo-cyanine iodide, cryptocyanine, Dicyanine ATM, Merocyanine 540TM, 4-(p-ethoxy-phenylazo)-m-phenylene diamine mono-hydrochloride, Yellow Orange STM, Chrysoidin GTM, fuchsin, aurintricarboxylic acid (ammonium salt), Victoria Blue RTM, Pyronin GTM, gallein, phloxine, Erythrosin Yellow BlendTM, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphosphine OTM, acriflavine, acridine orange, rhoduline violet, Alizarin Cyanin 2RTM, Alizarin Red STM, alcannin, Aurantia, Direct Green GTM, Fast Red Salt 3GLTM, Fast Blue Salt BBTM, Fast Garnet Salt GBCTM, Carta Yellow G 180 o/oTM, murexide, Savinyl Blue GLSTM, Irgalith Blue GLSMTM, phthalocyanine, Di Amingreen BTM, Alizarin Blue S, Celliton Blue ExtraTM, neocyanine, Janus Green, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow RTM, Eriochrome Black TTM, Chromotrope 2RTM, Ponceau 6RTM, Brilliant Ponceau G/R/2RTM, chromolan yellow, Sudan Red BTM, Bismarck brown GTM, Fat BlackTM, Resorcin BrownTM, Benzofast pink 2BLTM, Oil Red EGNTM, Euroglaucine, Fuchsin NBTM, parafuchsin, Patent BlueTM, Irgalith Blue TNCTM, Phloxin BTM, fluorescein sodium salt, Rhodamine B baseTM, Eosin Scarlet, Esoin YellowishTM, Erythrosin extra bluish, 4,5-dibromo-flucorescein, ethyleosin, PhloxineTM, Cyanovin BTM, chloro-cresol green, pinacyanol bromide, 2-(p-dime-thylamino-styryl)-1-ethyl pryidinium iodide ethyl red, neutral red iodide, nigrosine, savinyl blue BTM, Orasol Blue BLNTM, Safranin OTM, Azocarnun GTM, Phenosafranine, Azocarmine BXTM, Solophenyl Brilliant Blue BLTM, Nile Blue ATM, gallocyanine, gallamine blue, celestine blue, methylene green, Azure A/B/CTM, Blue VIF
OrganolTM, Alizarin, Nitrofast Green GSBTM, quinalizarine, Oil Blue NTM, Solvay purple, Ciba BlueTM, Indigo syntheticTM, Chromophtal Bordeaux RSTM, ThiorifolexTM, Acid Alizarin Red BTM, 5-Amino flourescein, Rose BengalTM, Martius YellowTM, Chicago Blue 6BTM, Alcian Blue 8GXTM, Cresyl violet, 4,4' Bis(dimethy-lamino)-benzylhdrol, Zinc Pthalocyanine, Sudan IIITM, Pyronin yTM, Toluylene BlueTM, cresyl violet perchlorate, Mendola's BlueTM, Phosphine Dye, NitronTM, cresyl violet acetate, Ceres Orange RTM, 4-phenylazo-1-naphtylamine, 4-(4-Dimethylamino-1-napthylazo)-3-methoxybenzene sulfonic acid, Bindschedler's GreenTM, and (p-dimethylamino-phenylazo) benzoic acid;

(2) a binary mixture of:
(A) at least one of a Group I body of compounds soluble in said solvent consisting of the halogenated sulfonphthaleins and the organic acids having a pK1 of less than or about four; and (B) at least one of a Group II body of compounds consisting of the aminotriphenylmethane and their soluble salts, 8-hydroxyquinoline, and the cyanines;
with the proviso that if the Group II compounds consist solely of at least one aminotriphenylmethanes or their soluble salts, then the Group I compound must be selected from at least one of the group consisting of oxalic acid, suitable soluble sulfonic acids and the tetrahalo-genated sulfonphthaleins, and the other soluble organic acids having a pK1 of less than or about 2, and wherein the weight ratio of the Group I body of compounds to the Group II body of compounds is more than or about 3 to 1;
and (3) at least one of the aforesaid Group III body of compounds with at least one of the Group I or Group II bodies of compounds.

36. The process to claim 35 wherein the solvent is a weakly polar or non-polar aromatic compound comprising one or more of o-chloroni-trobenzene, o-bromonitrobenzene, meta-iodonitrobenzene, para-iodonitrobenzene and para-toluic acid.

37. The process according to claim 35 wherein the solvent is a solid solution of o-chloronitrobenzene and o-bromonitrobenzene.

38. The process according to claim 35 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol red dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

39. The process according to claim 35 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromocresolpurple dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

40. The process according to claim 35 wherein the organic moiety is an effective amount of pinacyanol iodide dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

41. The process according to claim 35 wherein the organic moiety is an effective amount of a mixture of ethyl red and bromophenol blue dissolved in the solvent and subject to a color change upon a change in state of the solvent at a predetermined temperature.

42. The process according to claim 32 wherein hte nucleating agent is 9,10 anthraquinone.

43. The process according to claim 32 wherein the tem-perature of the mixture of thermally responsive material and matrix forming material is adjusted to room temperature before adding the nucleating agent.

43. The product prepared according to the process of claim 27.