CA1252241A - Heat/light stable interpenetrating polymer network latexes - Google Patents
Heat/light stable interpenetrating polymer network latexesInfo
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- CA1252241A CA1252241A CA000492145A CA492145A CA1252241A CA 1252241 A CA1252241 A CA 1252241A CA 000492145 A CA000492145 A CA 000492145A CA 492145 A CA492145 A CA 492145A CA 1252241 A CA1252241 A CA 1252241A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
- C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F291/00—Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to more than one of the groups C08F251/00 - C08F289/00
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- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polymerisation Methods In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Graft Or Block Polymers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Paper (AREA)
Abstract
ABSTRACT
An interpenetrating polymer network latex exhibiting heat and light stability and good mechanical properties comprising, a cross-linked hydrophilic polymer newtork having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and a hydrophobic polymer domain having at least one open chain conjugated diene monomer and/or at least one other hydrophobic monovinyl monomer, wherein the hydro-phobic polymer domain is emulsion polymerized in the cross-linked hydrophilic polymer network such that the hydrophilic polymer network forms a continuous phase;
and the hydrophobic polymer domain forms a discontinuous but mutually exclusive microdomain with each latex particle.
An interpenetrating polymer network latex exhibiting heat and light stability and good mechanical properties comprising, a cross-linked hydrophilic polymer newtork having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and a hydrophobic polymer domain having at least one open chain conjugated diene monomer and/or at least one other hydrophobic monovinyl monomer, wherein the hydro-phobic polymer domain is emulsion polymerized in the cross-linked hydrophilic polymer network such that the hydrophilic polymer network forms a continuous phase;
and the hydrophobic polymer domain forms a discontinuous but mutually exclusive microdomain with each latex particle.
Description
~s~
HEAT/LIG~T STABLE
INTERPENETRATING POLYMER NETWORK LATEXES
This invention relates to stable aqueous latex~s which exhibit improved heat and light stabil-it~, and good mechanical properties.
Aqueous dispersions of polymers, which are referred to in the art as latexes, are generally known to be useful, both alone and in various formulations, as coatings and impregnants. A wide variety of latexes of differing homopolymeric and copolymeric composition (such as styrene-butadiene copolymers, acrylic homo-polymers and copolymers, vinylidene chloride homopoly~mers and copolymers, e-tc.) have been developed having specific chemical and/or mechanical properties for particular end use applica-tions. For example, aqueous interpolymer latexes resulting from the emulsion polym erization of monovinylidene aroma-tic monomers, such as styrene; diolefins, such as bu-tadiene; and monoethyl-enically unsatura-ted carboxylic acids, such as acrylic acid; are known to be particularly useful as film-forming binders for pigments in paper coating applications, for example, U.S. Patent Nos. 3,399,080 and 3,404,116.
30,679-F -1-, ~
, . . .
,2i;~
Unfortunately, however, in the custom d~sign-ing of latexes having such specialized combina-tions of properties, the full range of flexibility which might be thought possible in theory (e.g., on the basis of the wide variety of known, desirable characteristics individually possessed by the nur.Lerous known classes - and-species of addition polymerizable monomeric ingre-.
dients~ have proven not to be entirely attainable in practice by virtue of complicating factors. Such factors include the incompat_bility as between -the individual c}asses and/or species of the known mono-meric materials; wide divergency of reactivity as between monomeric materials, and the like.
It is desirable that a latex exhibits sub-stantial stability towards decomposition or discolora-tion upon exposure to heat and light. For example, s-tyrene/butadiene type latexes do not exhibit good heat and light stability. However, it is desirable to incorporate styrene and butadiene into latexes as such latexes exhibit good elastomeric properties as well as other desirable physical properties such as elongation, tensil and modulus. In addition, it is often desirable to prepare ignition resistant latexes for some applica-tions. Unfortunately, common latexes do not often exhibit substan-tial heat and light stability toward decomposition and especially toward discoloration.
In recognition of the foregoing difficulties, attempts have been made in the prior art to overcome, or to at least minimize such difficulties. For example, in U.S. Patent No. 4,002,801, it is taught that certain reactive monomers which are not readily copolymerizable with other monomers can nevertheless be satisfactorily introduced to a latex particle by encapsulatlng or 30,679-F -2-
HEAT/LIG~T STABLE
INTERPENETRATING POLYMER NETWORK LATEXES
This invention relates to stable aqueous latex~s which exhibit improved heat and light stabil-it~, and good mechanical properties.
Aqueous dispersions of polymers, which are referred to in the art as latexes, are generally known to be useful, both alone and in various formulations, as coatings and impregnants. A wide variety of latexes of differing homopolymeric and copolymeric composition (such as styrene-butadiene copolymers, acrylic homo-polymers and copolymers, vinylidene chloride homopoly~mers and copolymers, e-tc.) have been developed having specific chemical and/or mechanical properties for particular end use applica-tions. For example, aqueous interpolymer latexes resulting from the emulsion polym erization of monovinylidene aroma-tic monomers, such as styrene; diolefins, such as bu-tadiene; and monoethyl-enically unsatura-ted carboxylic acids, such as acrylic acid; are known to be particularly useful as film-forming binders for pigments in paper coating applications, for example, U.S. Patent Nos. 3,399,080 and 3,404,116.
30,679-F -1-, ~
, . . .
,2i;~
Unfortunately, however, in the custom d~sign-ing of latexes having such specialized combina-tions of properties, the full range of flexibility which might be thought possible in theory (e.g., on the basis of the wide variety of known, desirable characteristics individually possessed by the nur.Lerous known classes - and-species of addition polymerizable monomeric ingre-.
dients~ have proven not to be entirely attainable in practice by virtue of complicating factors. Such factors include the incompat_bility as between -the individual c}asses and/or species of the known mono-meric materials; wide divergency of reactivity as between monomeric materials, and the like.
It is desirable that a latex exhibits sub-stantial stability towards decomposition or discolora-tion upon exposure to heat and light. For example, s-tyrene/butadiene type latexes do not exhibit good heat and light stability. However, it is desirable to incorporate styrene and butadiene into latexes as such latexes exhibit good elastomeric properties as well as other desirable physical properties such as elongation, tensil and modulus. In addition, it is often desirable to prepare ignition resistant latexes for some applica-tions. Unfortunately, common latexes do not often exhibit substan-tial heat and light stability toward decomposition and especially toward discoloration.
In recognition of the foregoing difficulties, attempts have been made in the prior art to overcome, or to at least minimize such difficulties. For example, in U.S. Patent No. 4,002,801, it is taught that certain reactive monomers which are not readily copolymerizable with other monomers can nevertheless be satisfactorily introduced to a latex particle by encapsulatlng or 30,679-F -2-
2~1 "overpolymerizing" the desired homopolymer or copolymer with a copolymer with which the desired reactive mono-mers are possible. Unfortunately, evlen such an improve-ment is not without disadvantages or limitations. For example, only certain types of encapsulating polymers are prac-ticable, and there exists an upper limit upon the amount of polymer solids that can be thereby pre-pared without latex flocculation or coagulation.
As taught in U.S. Patent No. 4,325,~56, aqueous copolymer lat~xes are prepared comprising colloidally dispersed, substantially spheroidal copolymer particles having a predominantly hydrophobic core portion and a relat.ively hydrophilic polymeric portion which is preferentially oriented toward the outer surface thereo~. Although such latexes provide desirable physical properties of various copolymeriz-able species, such latexes do not exhibit highly bal-anced physical properties.
Accordingly, it would be highly desirable to provide improved latexes and a process for making the same, by which polymers introduciny desirable combina-tions of properties to said latexes can be dispersed within one another to yield a desirable balance of mechanical properties.
The present invention is a structured latex particle having an interpenetrating polymer network.
The interpenetrating polymer network latex exhibiting heat and light stability and good physical properties comprises a cross-li.nked hydrophilic polymer network having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and a hydrophobic 30,679-F -3-~25,'~2~
polymer do~lain having at least one open chain con-jugated diene monomer and/or at least one other hydrophobic monovinyl monomer wherein the hydrophobic polymer domain is emulsion polymerized in the cross--linked hydrophilic polymer network such that said hydrophilic polymer network forms a continuous phase;
and said hydrophobic polymer domain forms a discon-tinuous but mutally exclusive.microdomain within each latex partlcle. By the term, "good physical proper-ties" is meant that physical proper-ties such as ten-sile, elongatio.. and modulus approach those provided by a latex composed essentially of a hydrophobic polymer domain. That is, the unique properties of an IPN is a result of the combination o uni~ue properties oE the lndividual component polymers. The physical properties exhibited by an IPN are superior to -those properties exhibited by blends o latexes, each of which introduce stability and good physical properties to the blend.
The structured latexes of this invention are broadly described as being interpenetrating polymer networks (IPNs) based on the two types of polymers, each in network form. For purposes of this invention, the morphology of each IPN latex particle is composed of microdomains of essentially hydrophobic polymer in an essentially continuous hydrophilic polymer phase.
The IPN latexes of this invention are useful where mechanically stable latexes have been previously used and where heat stability and ignition resistance are desirable. Uses include paper coatinys, carpet backsizing, composite papers, fabric coatings, nonwoven ma-terials, foil scrim kraft laminates, cement applica-tions, and other known applications.
30,679-F -4-~2~
An interpenetrating polymer network (IPN) is a uni~ue type of polymer blend which c:an be defined as a combination of two polymers in essentially a network form. The compositions of this invent:ion are prepared by incorporating monovinyl monomer~s) and optionally, though preferably,. a conjugated diene crosslinking agent (Stage .I mix) into an already existing, or at -least partially exisiting, crosslinked polymer network ..
~Polymer I), preferably by swelling, and then polymer-izing the Stage II mix in situ (along with the furtherpolymerization of the Polymer I network if necessary) to form a second polymer network (Polymer II). One polymer network is continuous throughout the composi-tion and both networks are essentially chemically independent. T.he unique featur~ of th~ IPNs o this invention is that khe networks ~re caused to inter-penetrate each other within the latex (i.e., both networks extend through large regions of space forming microdomains).
Polymer I networks or hydrophilic polymer networks employed in the practice of this invention generally are those which exhibit excellent heat and li~ht stability. Such heat and light stability is provided to the latex by the polymerization of monomers such as those which will, when polymerized, yield an essentially hydrophilic polymer ne-twork.
Suitable monomers which can polymerize to yield such hydrophilic polymers include the acrylate and methacrylate monomers and, for example, hydroxy-alkyl acrylates wherein the alkyl group contains from 2to about 4 carbon atoms such as 2-hydroxyethyl acrylate or 3-hydroxypropyl acrylate; alkyl acrylates wherein 30,679-F -5-~52;~ ~
the alkyl group contains from 1 to about 18 carbon atoms, such as methyl acrylate, ethyl acrylate, propyl acrylate, n--butyl acrylate, 2-ethylhexyl acrylate, etc., alkyl methacrylates, such as methyl methacrylate, ethyl methacryla-te, propyl methacryal-te, n-butyl meth-acryla-~e, and similar alkyl methacrylates.
Other monomers which are advantageously copolymerized in the preparation of the Polymer I
include amides derived from ~ olefinically unsat--ur~ted carboxylic acids and include, for example,acrylamide, methacrylamide, N-methyl acrylamide, n-ethyl acrylamide, N-propyl acrylamide, N-(t-buty:L)-~acrylamide, N (2-eth~lhexyl) acrylamide, N-methyl methacrylamide, N-(t~butyl) methacrylamide, N-octy:l methacrylamide, N,N-diethyl acrylamide, N,N-diethyl methacrylamide, and diace-tone acrylamide.
Other monomers can include the N-alkylol and N-alkoxyalkyl derivatives of the aforementioned olefin-ically unsaturated amides and include, for example, N-methylol acrylamide, N-ethanol methacrylamide, N-propanol acrylamide, N-methoxymethyl acrylamide, N-methoxyethyl acrylamide, N-butoxyekhyl acrylamide, N-butoxymethyl methacrylamide, and the like. While the above-mentioned monomers are preferred because of their ready availability and low cos-t, other structurally related polymerizable amides, such as N-methylol male-amide, N-methylol maleimide, N-methylol-p-vinyl benz-imide, and the hydroxyalkyl derivatives of diacetone acrylamide can also be employed.
. Other monomers can include acrylonitrile, methacrylonitrile, vinyl acetate, vinyl formate, vinyl propionate, propylene, butylene, pentene, methylvinyl 30,679-F -6-~5~,~
ether, ethyl vinyl ether, vinyl 2-methoxyl ethyl ether, and vinyl 2-chloroethylether.
Especially preferred other monomers include the ~ olefinically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, vinyl benzoic acid, isopropenyl benzoic acid, ~-diloroacrylic acid, cro-tonic acid, sorbic acid, ~-st-yryl ac-rylic acid, glu-tonic acid, and aconitic acid.
Other especially preferred monomers include the monovinylidene aromatic monomers which include, for example, styrene, a-methylstyrene, ortho-, meta~and para-methylstyrene, ortho-, meta- and paraAethylstyrene, o,p-dimethylstyrene, o,p-diethylstyrene, o-methyl-p-isopropyls-tyrene, p-chlorostyrene, p-bromostyrene, o,p-dichlorostyrene, and o,p-dibromostyrene.
The polyvinyl crosslinking monomer for the purposes of this invention is a di- or polyfunctional ethylenically unsaturated monomer having at least one a,~-ethylenically unsaturated vinyl group. The vinyl groups on the crosslinking monomer are the same such as, for example, in divinyl benzene, and trimethyol propane triacrylate; or different such as, for example, in allyl methacrylate, diallyl fumarate, and diallyl malea-te, Fxamples of o-ther suitable crosslinking monomers include 1,3-butylene dimethacryla-te, diethylene glycol dimethacryla-te, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, methylene bisacryl-amide, diethylene glycol diacrylate, ethylene glycol diacrylate, divinyl ether, diallyl phthalate, tri-ethylene glycol dimethacrylate, trimethylene glycoldiacrylate, butylene glycol diacrylate, pen-tamethylene glycol diacrylate, glyceryl triacrylate, octylene ylycol 30,679-F -7-, diacrylate, trime-thylolpropane triacrylate, and the tetraacrylate ester of pentaerythritol.
Polymer II domains or hydrophobic polymer domains employed in the practice of this invention .exhibit excellent elastomeric proper.ties, ignition resistance, or other desirable mechanical properties to the latex. In particular, such properties are provided by selecting the proper monomers which can be polymer-ized with suitable crosslinking monomers such as the aliphatic conjugated diene monomers.
The open chain conjugated diene monomers t~oically contain from 4 to about 9 carbon atoms and such monomers :include 1,3-butadiene, 2-methyl-1,3-buta~
diene, 2,3-dimethyl-1,3-butadiene, pentadiene 2-neopentyl--1,3-butadiene and other hydrocarbon analogs of 1,3-buta-diene, and in addition, the substituted 1,3-butadienes such as l-chloro-1,3-butadiene; 2-cyano 1,3-butadiene;
the substituted straight chain conjugated pentadienesi the straight and branched chain conjuga-ted hexadienes;
other straight chain and branched chains conjugated dienes preferably having from 4 to about 9 carbon atoms and comonomeric mixtures thereof. The 1,3-butadiene hydrocarbon monomers such as those mentioned herein-before provide polymers having particularly desirable properties and are therefore preferred with 1,3-buta-diene the most preferred.
Suitable monomers employed in the Polymer II
mix include the aforementioned monovinylidene aromatic monomers, and vinyl halide or vinylidene halide monomers (hereinafter simply referred to as vinyl halide monomers).
Suitable halogens are selected from the group consisting 30,679-F -8-~2S;2;~
g of chloro, bromo and fluoro. Especially useful vinyl halide monomers include vinyl chloride and vinylidene chloride, and may be employed individually or in com-bination.
When the Polymer II exhibits "soft" charac~
teristics (i.e., a Tg of about 25C ox less), the physical properties such as moduli of elasticity and tensile strength which are exhibited by the I~N are essentially those exhibited by the Polymer I network.
However, if Polymer II exhibits very "hard" character (i.e., Tg of 80C or more), the corresponding physical properties are dominated by the Polymer II character, and are essentially independent of Polymer I. Further, khe IPN latexes show better heat stability in terms of color and flexibility. Such a behavior is expected in view of the fact that the Polymer I constituents are heat stable and maintain good flexibility. In practice, as the Polymer II constituents degrade, less discolora-tion is shown because it is believed that degradation within the small microdomains is less pronounced than that exhibited in a large homogeneous domain.
Polymer I networks generally comprise (1) from 50 to 100, preferably 60 to 80, weight percent acrylate or methacrylate monomers, (2) up to 50, preferably 20 to 40, weight percent monovinyl aroma-tic monomer, (3) up-to 10, preferably 2 to 8, weight percent other vinyl monomer, preferably an unsaturated carboxylic acid, and (4) up to 2, preferably 0.2 to 1, weight percent polyvinyl crosslinking monomer.
30,679-F -9-Polymer II networks generally comprise (1~
up to 100, preferably 50 to 80, weight percent mcno-vinylidene aromatic monomers, and (2) up to 100, pre-ferably 20 to 50, weight percent open chain conjugated diene monomer; or (1) up to 100, preferably 5~ to 80, weight percent ~inylidene chloride, and (2) up to 100, preferably 20 to 50 weight percent conjugated diene - monomer. - . -In the modes of preparing the latexes of the invention, the individual polymerization stages are most preferably conducted pursuant to conventional emulsion polymerization techniques. Thus, for example, the monomers to be employed in the particular stage involved are typically dispersed, with agitation suf-Eicient to emulsiEy the mixture, in an aqueous mediumwhich may contain known emulsifying agents (i.e., surfactants) as well as other ingredients convention-ally employed in the art as polymerization aids (e.g., conventional chain transfer agents, etc.). Such mono-mers are then subjected to polymerization with the aidof a conventional source or generating free radicals (i.e., conventional free radical polymerization cata-lysts, activating radiation, etc.~.
Free radical polymerization catalysts suitable for use in the foregoing polymerization stages lnclude those already known to promote emulsion polymerization.
Among such catalysts are oxidizing agents such as organic peroxides (e.g., t-butyl hydroperoxide, cumene hydroperoxide, etc.), inorganic oxidizing agents (e.g., hydrogen peroxide, potassium persulfate, sodium persul-fate, ammonium persulfate, etc.) and catalysts which, 30,679-F -10-like redox catalysts, are activated in the water phase, for example, by a water-soluble reducing agent.
Such catalysts are employed in an amount sufficient to cause polymerization (i.e., in a cat-alytic amount). As a general rule, an amount rangingfrom 0.01 to 5 weight percent based upon the total - monomer to be polymer-ized is sufficient. Al~erna~ -tively, other free radical producing means, such as exposure to activating radiations, can be employed rather than heat and/or catalytic compounds to activate the polymerization.
Suitable emulsifying agents which can be employed :include the anionic, cationic, and nonionic emulsifiers customarily used in emulsion polymerization.
Usually at least one anionic emulsifier is included and one or more nonionic emulsifiers can also be present.
Representative types of anionic emulsifiers are the alkyl aryl sulfonates, alkali metal alkyl sulfates, the sulfonates alkyl esters, and the fatty acid soaps.
Specific examples of these well known emulsifiers include dodecylbenzene sodium sulfonate, sodium butyl-naphthalene sulfonate, sodium lauryl sulfate, disodium dodecyl diphenyl ether disul~onate, N-octadecyl disodium sulfosuccina-te and dioctyl sodium sulfosuccinate. Such emulsifying agents can be employed in varying amounts so long as adequate emulsification is achieved to provide dispersed polymer particles having the desired particle size and particle size distribution. However, as a general rule, an amount ranging from 0.01 to 5 weight percent, based upon the total monomer to be polymerized, is advantageously employed. It should be noted, however, that it is preferable that no (or 30,679-F
~2~
only small amounts of) emulsifying agents are added in the aforementioned second stage polymerization. This feature is desirable in order that the majority of the second sta~e polymer is formed on or around existing first stage polymer particles rather than initiating substantial amounts of homogeneous second stage polymer particles.
Optionally, conventional seeding procedures can be employed in the first stage polymerization to aid in control of such polymerization and in achieving the desired average particle size and particle size distribution for the dispersed second stage copolymer particles. When used, the seed particles are typically employed in amounts corresponding to from 0.1 to 1 wei~ht percent oE the core comonomers. Generally such seed particles range in size from 10 to 20 percent of the diameter of the IPN latex particles to be formed.
The monomeric composition of the seed latex can vary so long as it does not coagulate during formation of the Stage I polymer particles.
As has been noted, conventional chain transfer agents can be employed in the practice of the present invention and, indeed, in polymerization stages employ-ing an aliphatic conjugated diene, it is preferable to do so. Examples of such conventional chain transfer agents include bromoform, carbon tetrachloride, long chain mercaptans (e.g., lauryl mercaptan, dodecyl mercaptan, etc.), or other ~nown chain transfer agents.
Conventional amounts (e.g., from 0.1 to 30 weight percent based on the total monomer charge) of such chain transfer agents are typically employed in such preferred embodiments.
30,679-F ~12-~s~
Other ingredients known in the art to be useful for various specific purposes in emulsion polym-erization can also be employed in the aforementioned polymerization stages. For example, when the polymeri-zable constituents for a given polymerization stageinclude a monoethylenically unsaturated carboxylic acid monomer, polymerization under acidic conditions (e.g., the aqueous media having a pH value of from 2 to 7, especially from 2 to 5) is preferred. In such instances, the aqueous medium can include acids and/or salts to provide the desired pH value and possible a buffe ed system. On the other hand, when a monoethylenically unsaturated carboxylic acid monomer is IlOt employed, the pH o~ the aqueous medium can conveniently range lS from 2 to 10.
The following general procedure is preferably employed in making the IPN latexes of the present invention. A reactor is used which is equipped with an appropriate agitator or stirrer. The reactor is also equipped with an injection device for adding initiators at the heginning and during the reaction. Premix tanks are employed in conjunction with the reactor and are connected thereto. For example, one tank is employed for premixing the monomers, and the other for premixing the initiators, and emulsifiers.
The reactor is charged with water (most preferably distilled and treated with a chelating agent to remove metal ions) and purged with nitrogen or other inert gas to remove the oxygen therefrom. Preferably, a polymer seed is added to the aqueous phase.
30,679-F -13-In the first premix tank, the monomer mix is prepared. In the second premix tank, water, emulsi-fiers, initiators, and optional chelating agents are added. The reactor temperature during polymerization is in the range of 30C to 100C, most preferably from 60C to 90C. Each of the premixtures is simultane-, ously or continuously added and the monomers is allowed ~ to react for a period from less than one hour to 6 hours.
After the initial monomer charge i'as been allowed to react, preferably with agitation, the Polymer I can be subjected to urther polymerization conditions. rn a manner similar to tha-t employed in preparing the Polymer I, to each of the premix tanks are added the Stage II monomer mix and the agueous mixture. The contents of each of the tanks are simul-taneously or continuously added, and allowed to react.
Reaction will be completed in 3 to 10 hours. The reactor is then cooled and the latex is filtered in order to remove any coagulum formed during the initial polymerization and during the second polymeri!zation.
Suitable particle sizes for the latex result-ing from such a process are generally obtained directly from such a polymerization process. Latexes generally 25 range in size from 0.05 to 0.4, preferably 0.08 to 0.3, most preferably about 0.1 to 0.25, micrometer in diameter.
Following polymerization, the solids content of the resulting agueous polymer latex can be adjusted to the level desired by adding water thereto or by distilling water therefrom. Generally, such desired 30,679-F -14-5;~
level of polymeric solids content is from 30 to 65 weight percent on a total weight basis.
The preferred IPN la-texes comprise from 20 to 90, most preferably 25 to 75, weight percent Polymer I, and from 10 to 80, most preferably 25 to 75, weight percent Polymer II. It is necessary that Polymer I be a-pxedominantly hydrophilic polymer in order for IPN
latexes to form. A predominantly hydrophobic Polymer I
will tend to act as a seed which will be encapsulated by hydrophilic polymers leading to an undesirable core-shell structure. It is also desirable that the Polymer I form the more continuous phase of the IPN.
This ensures good heat and light stability o~ the resulting IPN latex. Even through the Polymer II
lS network is preferably a less continuous phase (i.e., a smaller microdomain), it does form a network which provides a desirable balance of mechanical properties.
IPN latexes exhibit tensile strengths which are essentially independent of the amount of Polymer I
and Polymer II. However, an IPN having a Polymer I
composition of less than 30 weight percent, and a Polymer II composition of greater than 70 weight percent exhibits varying tensile strength as the amount of Polymer II increases. This suggests a more con-tinuous Polymer II phase beyond such a point.
.
The IPN latexes, because of the two indepen-dently continuous microdomains, exhibit a unique polymer compatibility. The microdomains do not undergo gross phase separation upon the introduction of heat to the latex. However, depending upon the amount of each 30,679-F -lS-polymer stage, the latex can exhibit two distinct but intermediate Tgs.
In addition, it is sometimes desirable to have small amounts of certain known additives incor-porated in the latex. Typical exampl~es of such additivesare surfactants, bacteriocides (e.g., formaldehyde), neutralizers, antifoamers, etc. Such additivRs can be incorporated into the latexes of the invention in a conventional manner and at any convenient point in the preparation of such latexes.
The aqueous IPN latexes of the present inven-tion are suitable for use in ~ variety of applications such as, ~or ~xample, in carpet backsizing, as b.inders in paper coating formulations, as binders for asbestos, as adhesives for binding together various types of substrates as free films and nonwoven fibers, as film--forming components for protective and/or decorative coatings (e.g., paints, etc.), and the like. The use of such latexes in the foregoing applications is pursuant to the techniques conventional in the respective arts.
Latexes employed in preparing films can be cured at fairly high temperatures. The products or articles resulting from the foregoing uses of the IPN latexes of this invention possess notably improved stability towards decompositon and/or discolora-tion (e.g., upon exposure to heat and light) relative to similar products employed conventional latexes of similar monomers.
The following example is intended to illustrate the invention and is not intended to limit the scope thereof. In the example, all parts and percentages are by weight unless otherwise specified.
.
30,679-F -16-- Example 1 Into a stainless steel jacketed reactor was charged 944.76 g of deionized water, 36 g of a 1 per-cent solution of a chelating agent, and 38.8 g of a 30.8 percent polystyrene polymer seed having an average - diameter of 280 A. The reactor was purged with nitrogen and heated under agitation to 90C.
A monomer mix comprised 780 g of butyl acrylate (65 parts), 372 g of styrene ~31 parts), 48 g of acrylic 10 acid (4 parts) and 2.4 g of allyl methacrylate (0.2 part).
This monomer mix was continuously added to the reactor at a rate of 400.8 g per hour for 3 hours.
~ n aqueous mix comprised 480 g o~ deioniz~d water, 26.6 g of a 45 percent surfactant, 18 g of a 10 percent sodium hydroxide solution and 8.4 g sodium persulfate. This aqueous mix was continuously added to the reactor as the monomer mix was added, but at a rate of 133.25 g per hour for 4 hours.
The mix-ture was allowed to cool down for an additional hour after all of the ingredients had been added -to the reactor. The resulting product was 44.9 percent solids, at a pH of 3.6, having very low residual monomer, 0.05 g of residue and an average particle diameter of 1310 A.
Into a reactor as previously described was charged 681 96 g of deionized water and 846 g of the polymer mixture described previously. The mixture was purged with nitrogen and heated under agitation at 90C.
30,679-F -17-A monomer mix comprises 420 g of styrene and 420 g of butadiene. This mix was continuously added to the reactor at a rate of 300 g pe~ hour for 2.8 hours.
An aqueous mix comprised 345.6 g of deionized water, 19.2 g of a 45 percent surfactant, 12.96 g of a .
lO percent sodium hydLoxide solution and 6 g of sodium persulfate. This aqueous mix was continuously added, but at a rate of 106.6 g per hour for 3.6 hours.
- The mi~sure was allowed to cool down for an additional 1.2 hours after all of the ingredients had been added to the reactor. The resulting product was 44.65 percent solids, at a pH of 3.4, having a very low residual monomer, 0.33 residue and an average particle size o~ 189S A.
30,679-F -18-
As taught in U.S. Patent No. 4,325,~56, aqueous copolymer lat~xes are prepared comprising colloidally dispersed, substantially spheroidal copolymer particles having a predominantly hydrophobic core portion and a relat.ively hydrophilic polymeric portion which is preferentially oriented toward the outer surface thereo~. Although such latexes provide desirable physical properties of various copolymeriz-able species, such latexes do not exhibit highly bal-anced physical properties.
Accordingly, it would be highly desirable to provide improved latexes and a process for making the same, by which polymers introduciny desirable combina-tions of properties to said latexes can be dispersed within one another to yield a desirable balance of mechanical properties.
The present invention is a structured latex particle having an interpenetrating polymer network.
The interpenetrating polymer network latex exhibiting heat and light stability and good physical properties comprises a cross-li.nked hydrophilic polymer network having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and a hydrophobic 30,679-F -3-~25,'~2~
polymer do~lain having at least one open chain con-jugated diene monomer and/or at least one other hydrophobic monovinyl monomer wherein the hydrophobic polymer domain is emulsion polymerized in the cross--linked hydrophilic polymer network such that said hydrophilic polymer network forms a continuous phase;
and said hydrophobic polymer domain forms a discon-tinuous but mutally exclusive.microdomain within each latex partlcle. By the term, "good physical proper-ties" is meant that physical proper-ties such as ten-sile, elongatio.. and modulus approach those provided by a latex composed essentially of a hydrophobic polymer domain. That is, the unique properties of an IPN is a result of the combination o uni~ue properties oE the lndividual component polymers. The physical properties exhibited by an IPN are superior to -those properties exhibited by blends o latexes, each of which introduce stability and good physical properties to the blend.
The structured latexes of this invention are broadly described as being interpenetrating polymer networks (IPNs) based on the two types of polymers, each in network form. For purposes of this invention, the morphology of each IPN latex particle is composed of microdomains of essentially hydrophobic polymer in an essentially continuous hydrophilic polymer phase.
The IPN latexes of this invention are useful where mechanically stable latexes have been previously used and where heat stability and ignition resistance are desirable. Uses include paper coatinys, carpet backsizing, composite papers, fabric coatings, nonwoven ma-terials, foil scrim kraft laminates, cement applica-tions, and other known applications.
30,679-F -4-~2~
An interpenetrating polymer network (IPN) is a uni~ue type of polymer blend which c:an be defined as a combination of two polymers in essentially a network form. The compositions of this invent:ion are prepared by incorporating monovinyl monomer~s) and optionally, though preferably,. a conjugated diene crosslinking agent (Stage .I mix) into an already existing, or at -least partially exisiting, crosslinked polymer network ..
~Polymer I), preferably by swelling, and then polymer-izing the Stage II mix in situ (along with the furtherpolymerization of the Polymer I network if necessary) to form a second polymer network (Polymer II). One polymer network is continuous throughout the composi-tion and both networks are essentially chemically independent. T.he unique featur~ of th~ IPNs o this invention is that khe networks ~re caused to inter-penetrate each other within the latex (i.e., both networks extend through large regions of space forming microdomains).
Polymer I networks or hydrophilic polymer networks employed in the practice of this invention generally are those which exhibit excellent heat and li~ht stability. Such heat and light stability is provided to the latex by the polymerization of monomers such as those which will, when polymerized, yield an essentially hydrophilic polymer ne-twork.
Suitable monomers which can polymerize to yield such hydrophilic polymers include the acrylate and methacrylate monomers and, for example, hydroxy-alkyl acrylates wherein the alkyl group contains from 2to about 4 carbon atoms such as 2-hydroxyethyl acrylate or 3-hydroxypropyl acrylate; alkyl acrylates wherein 30,679-F -5-~52;~ ~
the alkyl group contains from 1 to about 18 carbon atoms, such as methyl acrylate, ethyl acrylate, propyl acrylate, n--butyl acrylate, 2-ethylhexyl acrylate, etc., alkyl methacrylates, such as methyl methacrylate, ethyl methacryla-te, propyl methacryal-te, n-butyl meth-acryla-~e, and similar alkyl methacrylates.
Other monomers which are advantageously copolymerized in the preparation of the Polymer I
include amides derived from ~ olefinically unsat--ur~ted carboxylic acids and include, for example,acrylamide, methacrylamide, N-methyl acrylamide, n-ethyl acrylamide, N-propyl acrylamide, N-(t-buty:L)-~acrylamide, N (2-eth~lhexyl) acrylamide, N-methyl methacrylamide, N-(t~butyl) methacrylamide, N-octy:l methacrylamide, N,N-diethyl acrylamide, N,N-diethyl methacrylamide, and diace-tone acrylamide.
Other monomers can include the N-alkylol and N-alkoxyalkyl derivatives of the aforementioned olefin-ically unsaturated amides and include, for example, N-methylol acrylamide, N-ethanol methacrylamide, N-propanol acrylamide, N-methoxymethyl acrylamide, N-methoxyethyl acrylamide, N-butoxyekhyl acrylamide, N-butoxymethyl methacrylamide, and the like. While the above-mentioned monomers are preferred because of their ready availability and low cos-t, other structurally related polymerizable amides, such as N-methylol male-amide, N-methylol maleimide, N-methylol-p-vinyl benz-imide, and the hydroxyalkyl derivatives of diacetone acrylamide can also be employed.
. Other monomers can include acrylonitrile, methacrylonitrile, vinyl acetate, vinyl formate, vinyl propionate, propylene, butylene, pentene, methylvinyl 30,679-F -6-~5~,~
ether, ethyl vinyl ether, vinyl 2-methoxyl ethyl ether, and vinyl 2-chloroethylether.
Especially preferred other monomers include the ~ olefinically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, vinyl benzoic acid, isopropenyl benzoic acid, ~-diloroacrylic acid, cro-tonic acid, sorbic acid, ~-st-yryl ac-rylic acid, glu-tonic acid, and aconitic acid.
Other especially preferred monomers include the monovinylidene aromatic monomers which include, for example, styrene, a-methylstyrene, ortho-, meta~and para-methylstyrene, ortho-, meta- and paraAethylstyrene, o,p-dimethylstyrene, o,p-diethylstyrene, o-methyl-p-isopropyls-tyrene, p-chlorostyrene, p-bromostyrene, o,p-dichlorostyrene, and o,p-dibromostyrene.
The polyvinyl crosslinking monomer for the purposes of this invention is a di- or polyfunctional ethylenically unsaturated monomer having at least one a,~-ethylenically unsaturated vinyl group. The vinyl groups on the crosslinking monomer are the same such as, for example, in divinyl benzene, and trimethyol propane triacrylate; or different such as, for example, in allyl methacrylate, diallyl fumarate, and diallyl malea-te, Fxamples of o-ther suitable crosslinking monomers include 1,3-butylene dimethacryla-te, diethylene glycol dimethacryla-te, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, methylene bisacryl-amide, diethylene glycol diacrylate, ethylene glycol diacrylate, divinyl ether, diallyl phthalate, tri-ethylene glycol dimethacrylate, trimethylene glycoldiacrylate, butylene glycol diacrylate, pen-tamethylene glycol diacrylate, glyceryl triacrylate, octylene ylycol 30,679-F -7-, diacrylate, trime-thylolpropane triacrylate, and the tetraacrylate ester of pentaerythritol.
Polymer II domains or hydrophobic polymer domains employed in the practice of this invention .exhibit excellent elastomeric proper.ties, ignition resistance, or other desirable mechanical properties to the latex. In particular, such properties are provided by selecting the proper monomers which can be polymer-ized with suitable crosslinking monomers such as the aliphatic conjugated diene monomers.
The open chain conjugated diene monomers t~oically contain from 4 to about 9 carbon atoms and such monomers :include 1,3-butadiene, 2-methyl-1,3-buta~
diene, 2,3-dimethyl-1,3-butadiene, pentadiene 2-neopentyl--1,3-butadiene and other hydrocarbon analogs of 1,3-buta-diene, and in addition, the substituted 1,3-butadienes such as l-chloro-1,3-butadiene; 2-cyano 1,3-butadiene;
the substituted straight chain conjugated pentadienesi the straight and branched chain conjuga-ted hexadienes;
other straight chain and branched chains conjugated dienes preferably having from 4 to about 9 carbon atoms and comonomeric mixtures thereof. The 1,3-butadiene hydrocarbon monomers such as those mentioned herein-before provide polymers having particularly desirable properties and are therefore preferred with 1,3-buta-diene the most preferred.
Suitable monomers employed in the Polymer II
mix include the aforementioned monovinylidene aromatic monomers, and vinyl halide or vinylidene halide monomers (hereinafter simply referred to as vinyl halide monomers).
Suitable halogens are selected from the group consisting 30,679-F -8-~2S;2;~
g of chloro, bromo and fluoro. Especially useful vinyl halide monomers include vinyl chloride and vinylidene chloride, and may be employed individually or in com-bination.
When the Polymer II exhibits "soft" charac~
teristics (i.e., a Tg of about 25C ox less), the physical properties such as moduli of elasticity and tensile strength which are exhibited by the I~N are essentially those exhibited by the Polymer I network.
However, if Polymer II exhibits very "hard" character (i.e., Tg of 80C or more), the corresponding physical properties are dominated by the Polymer II character, and are essentially independent of Polymer I. Further, khe IPN latexes show better heat stability in terms of color and flexibility. Such a behavior is expected in view of the fact that the Polymer I constituents are heat stable and maintain good flexibility. In practice, as the Polymer II constituents degrade, less discolora-tion is shown because it is believed that degradation within the small microdomains is less pronounced than that exhibited in a large homogeneous domain.
Polymer I networks generally comprise (1) from 50 to 100, preferably 60 to 80, weight percent acrylate or methacrylate monomers, (2) up to 50, preferably 20 to 40, weight percent monovinyl aroma-tic monomer, (3) up-to 10, preferably 2 to 8, weight percent other vinyl monomer, preferably an unsaturated carboxylic acid, and (4) up to 2, preferably 0.2 to 1, weight percent polyvinyl crosslinking monomer.
30,679-F -9-Polymer II networks generally comprise (1~
up to 100, preferably 50 to 80, weight percent mcno-vinylidene aromatic monomers, and (2) up to 100, pre-ferably 20 to 50, weight percent open chain conjugated diene monomer; or (1) up to 100, preferably 5~ to 80, weight percent ~inylidene chloride, and (2) up to 100, preferably 20 to 50 weight percent conjugated diene - monomer. - . -In the modes of preparing the latexes of the invention, the individual polymerization stages are most preferably conducted pursuant to conventional emulsion polymerization techniques. Thus, for example, the monomers to be employed in the particular stage involved are typically dispersed, with agitation suf-Eicient to emulsiEy the mixture, in an aqueous mediumwhich may contain known emulsifying agents (i.e., surfactants) as well as other ingredients convention-ally employed in the art as polymerization aids (e.g., conventional chain transfer agents, etc.). Such mono-mers are then subjected to polymerization with the aidof a conventional source or generating free radicals (i.e., conventional free radical polymerization cata-lysts, activating radiation, etc.~.
Free radical polymerization catalysts suitable for use in the foregoing polymerization stages lnclude those already known to promote emulsion polymerization.
Among such catalysts are oxidizing agents such as organic peroxides (e.g., t-butyl hydroperoxide, cumene hydroperoxide, etc.), inorganic oxidizing agents (e.g., hydrogen peroxide, potassium persulfate, sodium persul-fate, ammonium persulfate, etc.) and catalysts which, 30,679-F -10-like redox catalysts, are activated in the water phase, for example, by a water-soluble reducing agent.
Such catalysts are employed in an amount sufficient to cause polymerization (i.e., in a cat-alytic amount). As a general rule, an amount rangingfrom 0.01 to 5 weight percent based upon the total - monomer to be polymer-ized is sufficient. Al~erna~ -tively, other free radical producing means, such as exposure to activating radiations, can be employed rather than heat and/or catalytic compounds to activate the polymerization.
Suitable emulsifying agents which can be employed :include the anionic, cationic, and nonionic emulsifiers customarily used in emulsion polymerization.
Usually at least one anionic emulsifier is included and one or more nonionic emulsifiers can also be present.
Representative types of anionic emulsifiers are the alkyl aryl sulfonates, alkali metal alkyl sulfates, the sulfonates alkyl esters, and the fatty acid soaps.
Specific examples of these well known emulsifiers include dodecylbenzene sodium sulfonate, sodium butyl-naphthalene sulfonate, sodium lauryl sulfate, disodium dodecyl diphenyl ether disul~onate, N-octadecyl disodium sulfosuccina-te and dioctyl sodium sulfosuccinate. Such emulsifying agents can be employed in varying amounts so long as adequate emulsification is achieved to provide dispersed polymer particles having the desired particle size and particle size distribution. However, as a general rule, an amount ranging from 0.01 to 5 weight percent, based upon the total monomer to be polymerized, is advantageously employed. It should be noted, however, that it is preferable that no (or 30,679-F
~2~
only small amounts of) emulsifying agents are added in the aforementioned second stage polymerization. This feature is desirable in order that the majority of the second sta~e polymer is formed on or around existing first stage polymer particles rather than initiating substantial amounts of homogeneous second stage polymer particles.
Optionally, conventional seeding procedures can be employed in the first stage polymerization to aid in control of such polymerization and in achieving the desired average particle size and particle size distribution for the dispersed second stage copolymer particles. When used, the seed particles are typically employed in amounts corresponding to from 0.1 to 1 wei~ht percent oE the core comonomers. Generally such seed particles range in size from 10 to 20 percent of the diameter of the IPN latex particles to be formed.
The monomeric composition of the seed latex can vary so long as it does not coagulate during formation of the Stage I polymer particles.
As has been noted, conventional chain transfer agents can be employed in the practice of the present invention and, indeed, in polymerization stages employ-ing an aliphatic conjugated diene, it is preferable to do so. Examples of such conventional chain transfer agents include bromoform, carbon tetrachloride, long chain mercaptans (e.g., lauryl mercaptan, dodecyl mercaptan, etc.), or other ~nown chain transfer agents.
Conventional amounts (e.g., from 0.1 to 30 weight percent based on the total monomer charge) of such chain transfer agents are typically employed in such preferred embodiments.
30,679-F ~12-~s~
Other ingredients known in the art to be useful for various specific purposes in emulsion polym-erization can also be employed in the aforementioned polymerization stages. For example, when the polymeri-zable constituents for a given polymerization stageinclude a monoethylenically unsaturated carboxylic acid monomer, polymerization under acidic conditions (e.g., the aqueous media having a pH value of from 2 to 7, especially from 2 to 5) is preferred. In such instances, the aqueous medium can include acids and/or salts to provide the desired pH value and possible a buffe ed system. On the other hand, when a monoethylenically unsaturated carboxylic acid monomer is IlOt employed, the pH o~ the aqueous medium can conveniently range lS from 2 to 10.
The following general procedure is preferably employed in making the IPN latexes of the present invention. A reactor is used which is equipped with an appropriate agitator or stirrer. The reactor is also equipped with an injection device for adding initiators at the heginning and during the reaction. Premix tanks are employed in conjunction with the reactor and are connected thereto. For example, one tank is employed for premixing the monomers, and the other for premixing the initiators, and emulsifiers.
The reactor is charged with water (most preferably distilled and treated with a chelating agent to remove metal ions) and purged with nitrogen or other inert gas to remove the oxygen therefrom. Preferably, a polymer seed is added to the aqueous phase.
30,679-F -13-In the first premix tank, the monomer mix is prepared. In the second premix tank, water, emulsi-fiers, initiators, and optional chelating agents are added. The reactor temperature during polymerization is in the range of 30C to 100C, most preferably from 60C to 90C. Each of the premixtures is simultane-, ously or continuously added and the monomers is allowed ~ to react for a period from less than one hour to 6 hours.
After the initial monomer charge i'as been allowed to react, preferably with agitation, the Polymer I can be subjected to urther polymerization conditions. rn a manner similar to tha-t employed in preparing the Polymer I, to each of the premix tanks are added the Stage II monomer mix and the agueous mixture. The contents of each of the tanks are simul-taneously or continuously added, and allowed to react.
Reaction will be completed in 3 to 10 hours. The reactor is then cooled and the latex is filtered in order to remove any coagulum formed during the initial polymerization and during the second polymeri!zation.
Suitable particle sizes for the latex result-ing from such a process are generally obtained directly from such a polymerization process. Latexes generally 25 range in size from 0.05 to 0.4, preferably 0.08 to 0.3, most preferably about 0.1 to 0.25, micrometer in diameter.
Following polymerization, the solids content of the resulting agueous polymer latex can be adjusted to the level desired by adding water thereto or by distilling water therefrom. Generally, such desired 30,679-F -14-5;~
level of polymeric solids content is from 30 to 65 weight percent on a total weight basis.
The preferred IPN la-texes comprise from 20 to 90, most preferably 25 to 75, weight percent Polymer I, and from 10 to 80, most preferably 25 to 75, weight percent Polymer II. It is necessary that Polymer I be a-pxedominantly hydrophilic polymer in order for IPN
latexes to form. A predominantly hydrophobic Polymer I
will tend to act as a seed which will be encapsulated by hydrophilic polymers leading to an undesirable core-shell structure. It is also desirable that the Polymer I form the more continuous phase of the IPN.
This ensures good heat and light stability o~ the resulting IPN latex. Even through the Polymer II
lS network is preferably a less continuous phase (i.e., a smaller microdomain), it does form a network which provides a desirable balance of mechanical properties.
IPN latexes exhibit tensile strengths which are essentially independent of the amount of Polymer I
and Polymer II. However, an IPN having a Polymer I
composition of less than 30 weight percent, and a Polymer II composition of greater than 70 weight percent exhibits varying tensile strength as the amount of Polymer II increases. This suggests a more con-tinuous Polymer II phase beyond such a point.
.
The IPN latexes, because of the two indepen-dently continuous microdomains, exhibit a unique polymer compatibility. The microdomains do not undergo gross phase separation upon the introduction of heat to the latex. However, depending upon the amount of each 30,679-F -lS-polymer stage, the latex can exhibit two distinct but intermediate Tgs.
In addition, it is sometimes desirable to have small amounts of certain known additives incor-porated in the latex. Typical exampl~es of such additivesare surfactants, bacteriocides (e.g., formaldehyde), neutralizers, antifoamers, etc. Such additivRs can be incorporated into the latexes of the invention in a conventional manner and at any convenient point in the preparation of such latexes.
The aqueous IPN latexes of the present inven-tion are suitable for use in ~ variety of applications such as, ~or ~xample, in carpet backsizing, as b.inders in paper coating formulations, as binders for asbestos, as adhesives for binding together various types of substrates as free films and nonwoven fibers, as film--forming components for protective and/or decorative coatings (e.g., paints, etc.), and the like. The use of such latexes in the foregoing applications is pursuant to the techniques conventional in the respective arts.
Latexes employed in preparing films can be cured at fairly high temperatures. The products or articles resulting from the foregoing uses of the IPN latexes of this invention possess notably improved stability towards decompositon and/or discolora-tion (e.g., upon exposure to heat and light) relative to similar products employed conventional latexes of similar monomers.
The following example is intended to illustrate the invention and is not intended to limit the scope thereof. In the example, all parts and percentages are by weight unless otherwise specified.
.
30,679-F -16-- Example 1 Into a stainless steel jacketed reactor was charged 944.76 g of deionized water, 36 g of a 1 per-cent solution of a chelating agent, and 38.8 g of a 30.8 percent polystyrene polymer seed having an average - diameter of 280 A. The reactor was purged with nitrogen and heated under agitation to 90C.
A monomer mix comprised 780 g of butyl acrylate (65 parts), 372 g of styrene ~31 parts), 48 g of acrylic 10 acid (4 parts) and 2.4 g of allyl methacrylate (0.2 part).
This monomer mix was continuously added to the reactor at a rate of 400.8 g per hour for 3 hours.
~ n aqueous mix comprised 480 g o~ deioniz~d water, 26.6 g of a 45 percent surfactant, 18 g of a 10 percent sodium hydroxide solution and 8.4 g sodium persulfate. This aqueous mix was continuously added to the reactor as the monomer mix was added, but at a rate of 133.25 g per hour for 4 hours.
The mix-ture was allowed to cool down for an additional hour after all of the ingredients had been added -to the reactor. The resulting product was 44.9 percent solids, at a pH of 3.6, having very low residual monomer, 0.05 g of residue and an average particle diameter of 1310 A.
Into a reactor as previously described was charged 681 96 g of deionized water and 846 g of the polymer mixture described previously. The mixture was purged with nitrogen and heated under agitation at 90C.
30,679-F -17-A monomer mix comprises 420 g of styrene and 420 g of butadiene. This mix was continuously added to the reactor at a rate of 300 g pe~ hour for 2.8 hours.
An aqueous mix comprised 345.6 g of deionized water, 19.2 g of a 45 percent surfactant, 12.96 g of a .
lO percent sodium hydLoxide solution and 6 g of sodium persulfate. This aqueous mix was continuously added, but at a rate of 106.6 g per hour for 3.6 hours.
- The mi~sure was allowed to cool down for an additional 1.2 hours after all of the ingredients had been added to the reactor. The resulting product was 44.65 percent solids, at a pH of 3.4, having a very low residual monomer, 0.33 residue and an average particle size o~ 189S A.
30,679-F -18-
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. An interpenetrating polymer network latex exhibiting heat and light stability and good mechanical properties comprising:
a) a cross-linked hydrophilic polymer newtork having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and b) a hydrophobic polymer domain having at least one open chain conjugated diene monomer and/or at least one other hydrophobic monovinyl monomer, wherein said hydrophobic polymer domain is emulsion polymerized in said cross-linked hydrophilic polymer network such that said hydrophilic polymer network forms a continuous phase; and said hydrophobic polymer domain forms a discontinuous but mutually exclusive microdomain within each latex particle.
a) a cross-linked hydrophilic polymer newtork having at least one monovinyl monomer and at least one polyvinyl cross-linking monomer, and b) a hydrophobic polymer domain having at least one open chain conjugated diene monomer and/or at least one other hydrophobic monovinyl monomer, wherein said hydrophobic polymer domain is emulsion polymerized in said cross-linked hydrophilic polymer network such that said hydrophilic polymer network forms a continuous phase; and said hydrophobic polymer domain forms a discontinuous but mutually exclusive microdomain within each latex particle.
2. The latex of Claim 1 wherein said hydro-philic polymer network comprises (1) from 50 to 100 weight percent acrylate or methacrylate monomers, (2) up to 50 weight percent monovinyl aromatic monomer, (3) up to 10 weight percent other vinyl monomer, and (4) up to 2 weight percent polyvinyl crosslinking monomer. .
3. The latex of Claim 2 wherein said other vinyl monomer is an unsaturated carboxylic acid.
4. The latex of Claim 1 wherein said hydro-philic polymer network comprises (1) from 50 to 80 weight percent acrylate or methacrylate monomers, (2) from 20 to 40 weight percent monovinyl aromatic monomer, (3) from 2 to 8 weight percent other vinyl monomer, and (4) 0.2 to 1 weight percent polyvinyl crosslinking monomer.
5. The latex of Claim 4 wherein said other vinyl monomer is an unsaturated carboxylic acid.
6. The latex of Claim 1 wherein said hydro-phobic polymer domain comprises (1) up to 100 weight percent monovinyl aromatic monomer and (2) up to 100 weight percent open chain conjugated diene.
7. The latex of Claim 1 wherein said hydro-phobic polymer domain comprises (1) from 50 to 80 weight percent monovinyl aromatic monomer and (2) from 20 to 50 weight percent open chain conjugated diene.
8. The latex of Claim 1 wherein said hydro-phobic polymer domain comprises (1) up to 100 weight percent vinyl halide monomer and (2) up to 100 weight percent open chain conjugated diene.
9. The latex of Claim 1 wherein said hydro-phobic polymer domain comprises (1) from 25 to 75 weight percent vinyl halide monomer and (2) from 25 to 75 weight percent open chain conjugated diene.
10. The latex of Claim 1 comprising from 20 to 90 weight percent of said hydrophilic polymer network and from 10 to 80 weight percent of said hydrophobic polymer domain.
11. The latex of Claim 1 comprising from 25 to 75 weight percent of said hydrophilic polymer network and from 25 to 75 weight percent of said hydrophobic polymer domain.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/546,025 US4569964A (en) | 1983-10-27 | 1983-10-27 | Heat/light stable interpenetrating polymer network latexes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1252241A true CA1252241A (en) | 1989-04-04 |
Family
ID=24178548
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000492145A Expired CA1252241A (en) | 1983-10-27 | 1985-10-03 | Heat/light stable interpenetrating polymer network latexes |
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| US (1) | US4569964A (en) |
| EP (1) | EP0219562B1 (en) |
| JP (1) | JPS62101639A (en) |
| AU (1) | AU590219B2 (en) |
| CA (1) | CA1252241A (en) |
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|---|---|---|---|---|
| CN1995245B (en) * | 2006-12-15 | 2010-09-15 | 湖南工业大学 | Method for preparing thermosetting acrylic ester emulsion coating under room temperature |
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| US5190997A (en) * | 1985-07-10 | 1993-03-02 | Sequa Chemicals, Inc. | Adhesive composition |
| US4686260A (en) * | 1985-07-10 | 1987-08-11 | Sun Chemical Corporation | Printing ink composition |
| US5066708A (en) * | 1989-04-11 | 1991-11-19 | Rohm And Haas Company | Novel damping compositions |
| US5063091A (en) * | 1989-10-06 | 1991-11-05 | Rohm And Haas Company | Method for use of aqueous elastomeric coatings |
| DE69112453T2 (en) * | 1990-02-23 | 1996-02-29 | Nat Starch Chem Invest | Emulsion polymerization. |
| US5171768A (en) * | 1991-10-21 | 1992-12-15 | The Goodyear Tire & Rubber Company | Process for the production of carboxylated latexes by the selective monomer addition and polymerization |
| DE4315881A1 (en) * | 1993-05-12 | 1994-11-17 | Basf Ag | Two-stage copolymer |
| US5344867A (en) * | 1993-06-14 | 1994-09-06 | The Bfgoodrich Company | Vinylidene chloride emulsion interpolymer composition |
| US5770303A (en) * | 1994-07-06 | 1998-06-23 | Gencorp Inc. | Occluded composite-particle latex |
| CZ70097A3 (en) * | 1997-03-07 | 1998-09-16 | Jiří Ing. Šulc | Composite water-swelling elastomers and process for preparing thereof |
| JP2001316589A (en) * | 2000-05-02 | 2001-11-16 | Dow Corning Corp | Interpenetrating polymer network-including composition |
| US7429220B2 (en) * | 2001-04-13 | 2008-09-30 | Acushnet Company | Golf balls containing interpenetrating polymer networks |
| US7589158B2 (en) * | 2005-11-30 | 2009-09-15 | Columbia Insurance Company | Polymers with improved shelf stability |
| CN102161726B (en) * | 2010-12-23 | 2012-11-07 | 中国地质大学（北京） | Styrene-acrylate IPN/MMT nanocomposite damping material and preparation method thereof |
| CN104968628A (en) * | 2013-02-06 | 2015-10-07 | 巴斯夫欧洲公司 | Hybrid latex comprising polymeric particles having core-shell structure and its preparation method |
| WO2014122031A1 (en) * | 2013-02-06 | 2014-08-14 | Basf Se | Hybrid latex comprising polymeric particles having core-shell structure and its preparation method |
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| US4302553A (en) * | 1970-10-30 | 1981-11-24 | Harry L. Frisch | Interpenetrating polymeric networks |
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| FR2523985A1 (en) * | 1982-03-24 | 1983-09-30 | Rhone Poulenc Spec Chim | INTERPOLYMER LATEX, PROCESS FOR PREPARING THE SAME, AND APPLICATIONS IN PARTICULAR FOR SOLDING PAPER |
| US4569964A (en) * | 1983-10-27 | 1986-02-11 | The Dow Chemical Company | Heat/light stable interpenetrating polymer network latexes |
| JPH0676467B2 (en) * | 1984-12-18 | 1994-09-28 | 日本ペイント株式会社 | Composite resin particles and resin composition for paint |
| US4616057A (en) * | 1985-07-10 | 1986-10-07 | Sun Chemical Corporation | Polymer emulsion containing an interpenetrating polymer network |
-
1983
- 1983-10-27 US US06/546,025 patent/US4569964A/en not_active Expired - Fee Related
-
1985
- 1985-10-03 CA CA000492145A patent/CA1252241A/en not_active Expired
- 1985-10-07 AU AU48346/85A patent/AU590219B2/en not_active Ceased
- 1985-10-21 EP EP85113307A patent/EP0219562B1/en not_active Expired - Lifetime
- 1985-10-24 JP JP60236507A patent/JPS62101639A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1995245B (en) * | 2006-12-15 | 2010-09-15 | 湖南工业大学 | Method for preparing thermosetting acrylic ester emulsion coating under room temperature |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62101639A (en) | 1987-05-12 |
| EP0219562B1 (en) | 1991-09-04 |
| AU590219B2 (en) | 1989-11-02 |
| EP0219562A1 (en) | 1987-04-29 |
| US4569964A (en) | 1986-02-11 |
| AU4834685A (en) | 1987-04-09 |
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| MKEX | Expiry |