US3172777A

US3172777A - Process for depositing a water insoluble bactericide on a fabric

Info

Publication number: US3172777A
Authority: US
Publication date: 1965-03-09
Anticipated expiration: 1982-03-09

Description

March 9, 1965 P. v. PANO ETAL 3,172,777 PROCESS FOR DEPOSI'TING A WATER msowsw BACTERIOCIDE ON A FABRIC Filed April 10, 1963 Inventors PcTer If. Pawo I ld'duum R. Fiucefie M 9. 9M 12m jfuzzb Prlio melts United States Patent 3,172,777 PROCESS FOR DEPOSITING A WATER INSOLUBLE BACTERIOCIDE ON A FABRIC Peter V. Pane, Miami Shores, Fla, and William A. Faucette, Wheaten, 11L, assignors to Linen Supply Association of America, Miami, Fla, a corporation not for profit of Illinois Filed Apr. 10, 1963, Ser. No. 271,995 4 Claims. (Cl. 117-1385) The present invention relates to means for preventing growth on a fabric.

In the normal use of fabrics, such as toweling, in industrial or commercial service, or the like, one of the more important considerations is the prevention of growth upon the fabric. Prevention of such growth will prolong the effective useful life of the fabric. In the use of towels in commercial service, for example, it is customary for the users thereof to place the towel in a receptacle after use and to permit the towel to remain in the container for extended periods until the need for subsequent use arises. In view of the fact that the fabric normally is stored in a moist condition in warm areas, the conditions are especially conducive to growth on the surface of the fabric.

When the towel or fabric becomes soiled it will normally be discarded into a suitable receptacle and will remain in such receptacle until sent to a laundering service for cleansing. There usually will be an accumulation of towels within the receptacle and conditions therein are such that the growth of fungi, bacteria, etc. is considerably enhanced if the fabric has not been treated to retard or prevent such growth.

When the fabric is laundered subsequently, it often is difiicult to remove all traces of the growth from the fabric, and as a result, rather large laundering expenses may be encountered in attempting to satisfactorily cleanse soiled fabric. Further, uncontrolled growth upon the fabric will lead to premature deterioration of the fabric rendering it unsuitable for continued use and thus making it necessary to replace the fabric.

In view of this characteristic, it is necessary to treat the surface of the fabric in a manner adapted to retard or wholly prevent growth thereon at least for the period from one laundering to the next. The means employed to treat the fabric must not be water soluble due to the fact that from time to time, in use, the fabric, will be rinsed in a Water solution or may be employed to wipe up water solutions. If the growth preventing means were soluble in such solutions it would be eliminated from the fabric at an early stage and thus be ineffective in preventing growth. The means must be fairly stable in order to be retained on the fabric for the normal periods and conditions of use.

The process employed heretofore for depositing a growth preventing means, such as a mildicide, upon the fabric, involved placing the growth preventative into the last rinse of the laundering cycle and then depending upon deposit of the material upon the fabric during this rinse cycle. It can readily be seen that, for several reasons, this process is not totally satisfactory. The amount of mildicide required, for example, in the large volume rinse bath must be relatively large in order to build up the concentration therein to a level suitable to give reasonable assurance of deposition of the requisite amount of the effective ingredient of the growth preventing solution upon the surface of the fabric. Such process, further, is very inefficient in that it is difiicult to control the character of the solution and a large amount of the material in solution is lost at the end of each cycle when the rinse water is disposed preparatory to subsequent laundering cycles. It has been estimated that approximately to of the effective growth preventing means within the rinse bath is lost (depending upon the character of the solution) when the bath is drained from the laundering apparatus at the end of each cycle. In an industry where economy of operation is a very iI'IlPOl? tant factor, such wastefulness is of a character that identifies the specific area of the process as unsatisfactory and dictates that improvement be made.

In accordance with the present invention an improved means for prevention of growth upon a fabric is employed that is highly eflicient in operation. The process is effected by spraying a growth preventing means upon the surface of a fabric and then permitting the means to precipitate upon the surface after solution deposition thereon.

It is, therefore, a general object of the present invention to provide an improved process for the treatment of fabrics for the prevention of growth thereon.

It is an additional object of the present invention to provide an improved process for the treatment of fabrics for the prevention of growth thereon which process in volves the spraying of a growth preventing compound thereon during one stage of said processing cycle.

A further object of the present invention resides in the provision of an improved process for the treatment of fabrics which process involves the spraying of a mildicide upon the surface of a fabric after the laundering of saidfabric and prior to the ironing thereof.

Still a further object of the present invention resides in the provision of a method for the treatment of fabrics which process includes the spraying of a mildicide upon the fabric in the form of a solution and precipitating the effective portion of the solution upon the fabric during the ironing cycle of the process.

An additional object of the present invention resides in the provision of an improved method for the treatment of fabrics which process includes the spraying of'phenylmercuric acetate upon the fabric in the form of a solution and precipitating the effective mildicide from the solution upon the fabric during the ironing cycle of the process.

Another object of the present invention is to provide a process for the treatment of 'fabric wherein a growth preventing solution having an effectivegrowth' preventing means therein in solution at alkaline pH values is sprayed upon said fabricand is precipitated upon said fabric upon the subsequent application of heat thereto.

A further object of 'the present invention is to provide an alkaline solution of sodium pentachlorophenate income bination with a latent acid in which the acid becomes elfec tive upon the application of heat thereto to release free pentachlorophenol from solution.-

Still another object of the present invention resides in the provision of an improved process for the treatment of fabrics employing an alkaline solution of sodium pentachlorophenate in combination with a latent acid in which the acid is released in solution upon application of heat to said solution and wherein the acid is effective to precipitate free pentachlorophenol from solution and to deposit it upon the surface of the fabric to be treated.

An additional object of the present invention resides in the provision of a process for the treatment of fabrics which includes spraying said fabric with a solution containing a mildicide adapted to be precipitated upon the fabric upon application of heat to said solution treated fabric.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the-appended claims. Our invention itself, however, together with further objects and advantages thereof, will best be understood by reference to the following descriptions taken in connection with the accompanying drawings, in which:'

FIGURE 1 is a schematic representation of the process of the present invention illustrating the spraying and heating cycles of said process;

FIGURE 2 is a fragmentary view of the spray cabinet illustrating the spraying cycle in greater detail; and

FIGURE 3 is a fragmentary view of the conveyor belt utilized in the spraying cycle.

Referring more particularly now to FIGURES 1, 2 and 3 of the drawings, there is shown a laundering apparatus, indicated at 10. The laundering apparatus would be included in the industrial towel service specifically to cleanse the soiled fabric prior to spraying of the growth preventative thereon. It should be observed, however, that in the application of the process of the present invention to any other field it would be desirable to cleanse the material prior to application of the growth preventative for most effective results.

The cleansed, but still wet, fabric is transported from the laundering apparatus to the conveyor, indicated generally at 12 to be transported therealong through the subsequent operations. The conveyor 12 includes a conveyor belt 14 which is of woven net-like construction to permit passage of liquids therethrough and to provide an adequate support for the materials to be transported thereon. A fragmentary section of the conveyor belt 14 is illustrated in FIGURE 3. The belt 14 is drivingly engaged by conveyor rolls 16 and 18. The roll 16 is rotatably supported by the support member 20. The roll 18 is rotatably supported by the support member 22, said roll 18 being drivingly engaged through means 24 to a suitable driving means 26.

A spray chamber 28 is defined by walls 30 adapted to provide a suitable area within which spray equipment may be operatively mounted and within which the fabric may be sprayed. A supply pipe 32 leads to a header 34 adapted to feed a plurality of spray nozzles 36, which nozzles 36 are disposed above the fabric as it passes through the spray chamber 28. A second supply line 38 leads to a header 40 which header 40 is adapted to supply a plurality of nozzles 42 disposed below the fabric as it passes through the spray chamber 28. It should be observed that if a relatively narrow piece of material is being processed through the apparatus, it may only be necessary to have a single nozzle disposed above and below the upper and lower surfaces of the fabric, respectively, in order to assure full spray coverage of said fabric. This is, of course, also dependent upon the characteristics of the spray nozzle, pressure and other physical characteristics.

Each of the supply lines 32 and 38 is interconnected to a reservoir 44. The reservoir 44 is adapted to store the growth inhibitor solution 46 therein for use in the spray chamber, said inhibitor solution being fed to the

nozzles

36 and 42 through the supply lines 32 and 38 which define a continuous fluid connection therebetween. A valve 48 may be inserted in the common line leading to the supply lines to. control the flow of fluid from the reservoir.

The bottom of the chamber 28 is defined by converging walls terminating in an outlet 50, which outlet in turn is interconnected to the pump means 52. The pump 52 returns the growth inhibitor solution that falls to the bottom of the chamber as a result of being sprayed beyond the edges of the cloth, passing therethrough, etc. In this manner optimum utilization of the growth preventative or inhibitor solution is realized by recirculation to the reservoir 44 through the pump 52 and line 54.

The reservoir 44 may be a pressure container interconnected to a source of pressure indicated at 56. The pressure imposed upon the fluid 46 within the reservoir 44 propels the fluid to the

nozzles

36 and 42. It should be observed that pumps may be employed to bring the fluid 46. from the container to the

nozzles

36 and 42 in by conventional flatwork ironing process well known in the art. It should be observed that the ironer S8 is heated to an elevated temperature suflicient to assure towel flattening. This heat is employed in the present process not only to effect the flattening or ironing of the material as it passes therethrough, but also to precipitate the effective growth preventative agent out of solution.

After the fabric passes through the ironer 58, it is removed from the conveyor 12 and deposited in suitable packaging or storing apparatus for subsequent processing.

A spray chamber illustrative of the type employed herein is shown in cross section in FIGURE 2 wherein a plurality of

nozzles

36 and 42 are shown emanating from supply headers said nozzles being effective to pass a growth preventative solution therefrom onto the surface of the fabric passing through the spray chamber 28. The spray from the nozzles should be adjusted to effect complete coverage of the fabric passing through the chamber in order to assure the optimum deposition of growth preventative thereon and optimum protection.

For the purposes of the present invention the spraying chamber 28 and the ironer 58, in their simplest form need only be a means for application (by spraying) of the growth preventative solution to the surfaces of the fabric so that the solution will effectively permeate the same and a means for then heating the fabric to precipitate the growth preventative thereon and to remove the excess fluid from the fabric. As such, the ironer 58 need only be a heating chamber and would be such if there were no requirement that the fabric being treated be smoothed in the process. It is shown as an ironer in the present illustration only as it applies to towel laundering service applications, and is not to be construed as limited thereto.

The conventional manner of application of a growth inhibitor to a fabric involves the application thereof in the last rinse of the laundering cycle. The effective agent or growth preventative is placed into solution, in this method, and the solution is then added to the last rinse of the cycle. The effective agents commonly employed in such solutions are phenylmercuric acetate and pentachlorophenol.

The active ingredient, phenylmercuric acetate, for example, is added directly to the last rinse cycle in amounts sufficient to develop the proper solution concentration in combination with the volume of water employed in said rinse cycle. The deposition of the effective growth preventing ingredient upon the surface of the fabric is dependent upon contact of the fabric with said ingredient during the rinse cycle. It can readily be seen that non-uniform deposition of said ingredient upon the fabric may be achieved during such process due to the characteristics of a large quantity of fabric within the rinse bath. Further, the concentration of the ingredient within the solution may not be uniform and variations in deposition upon the cloth could result in this manner. In any event, predicability and reproducibility of a controlled level of deposition of phenylmercuric actate upon the surface of the fabric is not to be expected. In View of this fact, the tendency of the industry is to prepare the solution level of the rinse bath and the length of the cycle such that a substantially greater level than the optimum required will be achieved to assure at least minimum deposition upon all of the fabric within the bath. Such a process leads to inherent waste of materials and is of major concern, especially with the relatively expensive material such as phenylmercuric acetate.

As noted above, when phenylmercuric acetate is employed in the rinse bath of the laundering cycle, the amount thereof that must be added to the bath to leave an effective concentration on the fabric will depend upon (1) the total volume of water within the rinse bath and (2) the efiiciency of extraction of the effective growth preventative from the solution. It should be observed that phenylmercuric acetate is not preferentially absorbed upon the fabric, and thus the deposition of the phenylmercuric acetate upon the fabric after it has been fully processed is a function of the amount of water and solution that is present upon the fabric and is retained thereon after removal from the rinse cycle and passage through the water extraction cycle. The remainder of the solution, of course, is disposed of and is washed down the drain. It is to be noted that, under normal conditions, approximately 70% to 90% of the phenylmercuric acetate is lost hrough disposal along with the expended rinse water.

The pentachlorophenol, for example, which is the effective mildicide ingredient of sodium pentachlorophenate, is added to the rinse bath in the present process of treating fabrics in much the same manner as with the phenylmercuric acetate. The pentachlorophenol (PCP) is added to the rinse bath in the form of sodium pentachlorophenate. The PCP is released from the sodium form in acid solutions. The rinse bath, therefore, must be acidified to exhibit a hydrogen ion concentration of approxi mately pH or less. It can readily be seen that the operator of such equipment must observe the solution concentration of the rinse bath in order to be certain that the proper pH level is realized and that the level does not vary considerably during the cycle. The PCP will precipitate out only when the solution condition is on the indicated acid side, otherwise it will remain in solution in the rinse bath and will subsequently be washed down the drain with the disposal of the rinse water. In actual laundry operation the preparation of the rinse bath solution to achieve the proper pH concentration is frequently impossible or may not be achieved when desired with the subsequent result that the fabric in process is not treated and thus is not rendered resistant to the growth of mold, etc. thereon. It should also be observed that there frequently will be large variations in the PCP content on the fabric of discrete items within the same load being processed. This non-uniform deposition of PCP upon the fabric gives rise to problems. In view of this, it again is necessary to provide a stronger concentration of PCP in the solution than would be necessary if the deposition thereof upon the surface of material were realized in a more efficient manner. The concentration of the rinse bath could be realized through the use of sophisticated control systems adapted for such operation. The addition of such control systems to the laundering equipment, however, would render the operation uneconomical. It can readily be seen that if such controls were added to the processing equipment, not only would the initial investment be relatively high, but additional expenditures would be incurred in that it would then be necessary to employ an operator capable of understanding and operating equipment supplied with such controls. Such personnel ordinarily are highly skilled people that can command relatively high wages for their services. There is, of course, the additional problem of maintenance of such equipment, which of itself, may give rise to considerable expenditures. In view of the above it seems clear that such equipment is not in accord with that desired for optimum operation in conjunction with the process herein noted. It thus remains for the development of a simple, inexpensive method applicable to the present process, which method is adapted to apply the growth preventing means to the fabric in a fashion suitable to protect the material.

In one application of the method set forth herein toweling was sprayed to assess the effectiveness of the method and solutions employed therein.

The toweling was passed through the spray chamber of the apparatus at a rate of 60 feet per minute and sprayed with solution under a pressure of 40 p.s.i. The fabric or toweiing as fed to the spray chamber was at ironing moisture level and was passed directly from the spray chamber through a belt ironer. The belt and rollers of the apparatus were sprayed with a silicone solution to avoid water spotting of the toweling.

After ironing the treated towels were tested for growth resistance by inoculating with various mildew spores and placing them in conditions suitable for growth for a period of seven days. At the end of that period the towels were examined for growth. It was noted that those towels which had been treated with approximately 10 to 20 parts per million phenylmercuric-acetate exhibited satisfactory resistance to growth at the end of this period in that very little, if any, towel area was covered with spores.

Of those towels that had been rinsed in water in a manner that might be expected to occur in use of the towels, slightly more towel area was covered with spores.

In accord with the present invention an improved process for applying the effective growth preventing agent to the fabric was conceived, which process included spraying of the agent upon the surface of the fabric.

The process of the present invention, generally, involves the application of the effective growth preventative to the fabric by a spraying of mildicide solution thereon and then ironing or otherwise heating the fabric to deposit the efiective preventative ingredient on the fabric, all of which occurs, of course, after laundering, rinsing and extraction of excess fluid from the fabric.

In the most economical form of application the eifective agent employed in the process is pentachlorophenol (PCP). The active form of the commonly used growth preventative sodium pentachlorophenate is pentachlorophenol (POP). It is highly desirable that this agent be present on the fabric as PCP rather than as its sodium salt for two reasons. Initially, PCP appears to be a more effective growth preventative agent than its sodium salt, and second, PCP is water insoluble and it will not be removed from the fabric when it is rinsed in water during use.

In view of the fact that the PCP is insoluble in Water it was impractical to attempt to obtain a suitable solution there-of for effective application by spraying on the fabric. Emulsions of PCP are generally unsatisfactory as such emulsions generally are diflicult to handle in spraying.

Due to the fact that PCP is insoluble in water it is put into solution as its water soluble salt. The sodium salt is converted to PCP under acidic conditions. When the sodium salt is put into solution the resultant product is basic at least to the extent that the pH level is above 7. In this form the PCP will not precipitate out of the solution and further solution modification is required to put it in form such that subsequent precipitation of the PCP can be realized to make it available for deposition upon the fabric. It was necessary, in order to adapt this compound to a spraying application, to develop a compound that could be applied in a one-step procedure so that it may exhibit its mildicide action. The method generally in use heretofore involved a two step procedure of applying the sodium salt and then changing it to the free phenol form by application of acid. This procedure is generally unsatisfactory for application to the treatment of fabric in that careful control of the two step process is required, the disadvantage of treating materials with free acid and the necessity of handling free acid.

In order to achieve this, the solution of the present invention includes a chemical that is inert at ambient temperatures but becomes an acid when heated thereby to provide the conditions requisite for release of free PCP. One such chemical is gluconolactone, but it should be observed that others may be employed for this purpose. One such other material is sodium dihydrogen pyrophosphate which may be substituted for glucono-delta-lactone as the delayed action acidulating agent in the solution to be sprayed upon the surface of the fabric. It should also be observed that different levels of acidulating agent may be employed in the solution the minimum requirement for any given solution concentration being set at the amount necessary to give complete precipitation of the pentachlorophenol from solution upon application of heat to the solution treated fabric. Such latent acids are 7 effective in the process of laundering toweling, as presently practiced, in that the solution is sprayed upon the fabric after extraction of water succeeding the last rinse of the laundering cycle and then the fabric is processed through a fiat work ironer during which portion of the cycle the solution is heated to a level sufficient to activate the latent acid, to render the solution acidic, and to precipitate the PCP upon the fabric.

With the spraying process it can readily be seen that significant variations in deposition or concentration of the effective growth preventative upon the fabric may be avoided. Effective and uniform amounts of the growth preventative are applied to the surface in an inexpensive and economical fashion. There is no requirement for delicate control of the process in order to achieve optimum results and to that extent the inadequacies of the prior process for the application of growth preventatives have been obviated. The solutions employed in the practice of the process are very stable, can be compounded prior to use in the process and will remain in the effective form for indefinite periods of time. The concentration of the effective growth preventative within the solution is predetermined and controlled during compounding of the solution and thus the operator need not be concerned with such concentration, as heretofore practiced, during processing of every bath. Additional economies of operation are effected in that complete use of the solution is realized. Whatever material is not sprayed upon the fabric by, for example, going beyond the edges thereof, or simply being expelled therefrom in the spray chamber, is collected at the bottom of the spray chamber and recirculated to the storage reservoir for subsequent use. Thus, the solution is not lost down the drain as was characteristic of the prior practice.

Use of a mildicide such as phenylmercuric acetate in the process of the present invention generally is slightly less economical than when employing PCP as the mildicide. Phenylmercuric acetate is more expensive than PCP.

In one test of the process disclosed herein, the fabric was passed through the spray chamber and solution was sprayed thereon, the amount of solution comprising approximately 1l%, by weight, of the dry weight of the cloth. It was discovered that effective control of growth upon the fabric could be utilized by using a solution containing about 35 ppm. (parts per million) of phenylmercuric acetate. It was further noted that effective results were achieved with the use of spray tips (in the spray chamber) wherein the nozzle disposed above the fabric as it progressed through the spray chamber delivered 0.030 gallon of solution per minute and the nozzle disposed below the fabric as it progressed through the chamber delivered 0.077 gallon per minute, both at a pressure of 40 p.s.i. with a belt speed for the above given values at about 60 feet per minute. It should be observed that each of the above noted conditions are interrelated and are given as representative of only one effective combination suitable for the present process. ther variations may be realized, many of which may be equally effective in achieving the desired result.

The use of pentachlorophenol as the growth preventative in the present process dictated that the solution be prepared such that the PCP be in solution when sprayed upon the fabric. The insolubility of PCP in water solutions, of course, makes direct solution of PCP impossible. In view of this fact the solution of the present invention was developed wherein PCP as its sodium salt (which is readily soluble in water solutions) is dissolved in water and a chemical added to the solution, which chemical is inert in cold solutions but becomes an acid at elevated temperatures, such chemicals being commonly referred to as latent acids. To this extent the one such chemical involved is an acid salt of lactone which does not make its acid available in solution until heated to a temperature slightly in excess of 200 F. Two such specific chemical E5 agents that may be employed are glucono-delta-lactone and sodium dihydrogen pyrophosphate as delay action acidulating agents.

Glucono-delta-lactone, for example, hydrolyzes as the temperature is raised to release gluconic acid which in turn reacts with the sodium pentachlorophenol of the solution to give sodium gluconate and free pentachlorophenol, the latter being the effective growth preventative.

In the process disclosed herein, the solution hereinabove identified is sprayed upon the surface of the fabric as it passes through the spray chamber, sufficient amounts being sprayed thereon to saturate the fabric. The fabric is then conveyed to the ironer, which is adapted, con ventionally, to smooth the fabric as it passes therethrough. The level of heat within the ironing operation is sufficient to raise the temperature of the solution deposited on the cloth to a level in excess of that required to release the acidulating agent within the solution and to thereby effectuate precipitation of free PCP from the solution upon the fabric. It should be observed that the process disclosed herein is readily adapted to many other uses wherein a growth preventative must be added to a material. It is not essential that it be laundered material since the laundering thereof, while characteristic of the example noted herein, is not essential to performance of the novel process disclosed. The steps of spraying of the solution containing the effective growth preventative therein upon the surface of the fabric and then heating the fabric to precipitate the ECP therefrom may be adapted for many applications. For example, it may be desirable to treat fabric in bolts in a textile plant where the bolts are to be stored under conditions conducive to the promotion of growth. In such case the material might be sprayed with the solutions noted herein during processing and passed through a suitable heating chamber to heat the solution on the cloth thereby releasing the acidulating agent and permitting precipitation of the PCP. It should be noted that the process and product noted herein may also be employed in the treatment of paper and paper products to prevent growth thereon during periods of storage, for example. Paper for newsprint, or the like, usually is stored after processing and before use and must be treated with a suitable growth preventative in order to protect the product from deterioration prior to use. Paper may be processed in the manner set forth herein to assure prolonged protection of the fiber for periods of storage under conditions conducive to growth of mildicides or the like.

The solution disclosed herein is useful in applying a growth preventative to fabric and includes sodium pentachlorophenate which is stable at ambient temperatures but which precipitates pentachlorophenol, an effective bacteriocide or mildicide, at elevated temperatures.

Pentachlorophenol is insoluble in water, although the sodium salt, sodium pentachlorophenate is readily soluble in water solutions. The sodium salt, however, exhibits much poorer bacteriocidal and mildicidal activity than does pentachlorophenol and in such form is generally undesirable. The most desirable solution, for spraying purposes, is one where the PCP is in solute form at ambient temperatures for spraying upon the fabric and may be precipitated out of solution at a later point in processing so as to deposit the effective growth inhibitor, PCP, upon the fabric. Such compositions are not available in the form that would not deleteriously effect the material to which the solution will be applied.

The present disclosure provides for an alkaline solution of sodium pent-achlorophenate in combination with an acid salt which salt does not make its acid available in solution until heated. In such form the effective growth preventative may be precipitated from solution by raising the temperature of the solution thereby releasing the aeidulating agent and creating an acidic solution condition suitable for precipitation of the effective growth preventative therefrom.

The pH level of the solution preferably is controlled within the range of pH 10 to pH 11 with suitable alkaline compounds. However, the pH is not critical and can be varied without impairing the useful form of the solution. The pH preferably is kept on the basic side to assure that premature precipitation of the PCP will not occur.

Several solution concentrations were employed in the process set forth herein during tests of the solutions and process. For the conditions indicated hereinabove, that is, for a belt speed of about 60 feet per minute with a spray pressure of 40 p.s.i. it was found that solution concentrations of about 0.05% to about 0.07% pentachlorophenol were sufficient to assure satisfactory growth preventative deposits of active PCP upon the surface area of the toweling being treated. The solution concentrations would, of course, be varied in accord with spray and transport rates each of the various elements being interrelated for optimum treatment of the toweling.

One solution that was prepared for use in spraying fabric and that was found to be effective in use employed 1.45 grams of sodium pentachlorophenate which was dissolved in 1000 milliliters of water, then 1.50 grams of glucono-delta-lactone were added and the mixture was stirred until a clear solution resulted. The solution was then brought to a pH level of 10.3 with a 0.5 N sodium hydroxide solution.

Upon heating this solution to approximately the boiling point of water, pentachlorophenol precipitates therefrom and may be used to coat a fabric.

Varying solution concentrations may be achieved, for example, by dilution of the above noted solution to the desired concentration.

While the invention has been set forth specifically herein it will, of course, be understood that other modifications may be used without departing from the true spirit and scope of the invention. It is intended by the appended claims to cover all such modifications as fall within their true spirit and scope.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A process for depositing pentachlorophenol uniformly on fabric in precipitate form which comprises the sequential steps of spraying said fabric with an aqueous, alkaline solution containing sodium pentachlorophenate and glucono-delta-lactone and then ironing said fabric to concomitantly smooth the fabric and deposit pentachlorophenol thereon in precipitate form throughout the fabric.

2. A process for depositing pentachlorophenol on a fabric in precipitate form including the steps of spraying said fabric with an alkaline solution containing sodium pentachlorophenate and glucono-delta-lactone and then heating said fabric and the soution thereon to hydrolize said glucono-delta-lactone to release gluconic acid, said gluconic acid reacting with the sodium pentachlorophenate of said solution to provide free pentachlorophenol on said fabric.

3. A process for depositing pentachlorophenol on a fabric in precipitate form which includes the steps of spraying said fabric with an alkaline solution containing sodium pentachlorophenate and glucono-delta-lactone and then heating said fabric to deposit pentachlorophenol in precipitate form throughout the fabric.

4. A process for depositing water insoluble bacteriocide on a fabric to prevent growth of bacteria thereon comprising applying to said fabric an aqueous solution containing sodium pentachlorophenate as a soluble bacteriocide and glucono-delta-lactone as a latent acid adapted to release an acid compound upon application of heat thereto and at temperatures above a select level and heating said fabric and solution to a temperature above said level to cause the released acid to react with the soluble bacteriocida and precipitate the water insoluble bacteriocide pentachlorophenol on said fabric.

References Cited by the Examiner UNITED STATES PATENTS 2,483,008 9/49 Higgins 1l7-l38.5 XR 2,548,646 4/51 Bicknell et al. 117l38.5 XR

WILLIAM D. MARTIN, Primary Examiner.

Claims

1. A PROCESS FOR DEPOSITING PENTACHLOROPHENOL UNIFORMLY ON FABRIC IN PRECIPITATE FORM WHICH COMPRISES THE SEQUENTIAL STEPS OF SPRAYING SAID FABRIC WITH AN AQUEOUS, ALKALINE SOLUTION CONTAINING SODIUM PENTACHLOROPHENATE AND GLUCONO-DELTA-LACTONE AND THEN IRONING SAID FABRIC TO CONCOMITANTLY SMOOTH THE FABRIC AND DEPOSITE PENTACHLOROPHENOL THEREON IN PRECIPITATE FORM THROUGHOUT THE FABRIC.