CA1218783A - Process for preparing aqueous coatings comprising dispersible epoxy resin-acid polymer ester - Google Patents
Process for preparing aqueous coatings comprising dispersible epoxy resin-acid polymer esterInfo
- Publication number
- CA1218783A CA1218783A CA000443447A CA443447A CA1218783A CA 1218783 A CA1218783 A CA 1218783A CA 000443447 A CA000443447 A CA 000443447A CA 443447 A CA443447 A CA 443447A CA 1218783 A CA1218783 A CA 1218783A
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- Prior art keywords
- epoxy resin
- groups
- polymer
- epoxy
- carboxyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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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
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/10—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polymers containing more than one epoxy radical per molecule
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
Abstract
PROCESS FOR PREPARING AQUEOUS COATINGS COMPRISING
DISPERSIBLE EPOXY RESIN-ACID POLYMER ESTER
ABSTRACT
In a method for preparing a coating composition, an ionic polymer component containing sufficient carboxyl groups to render itself dispersible in water in neutralized form is prepared by reacting an epoxy resin containing 1,2-epoxy groups and an addition polymer containing carboxyl groups such that the resultant ionic polymer contains hydroxy ester groups from the reaction of 1,2-epoxy groups on said epoxy resin with carboxyl groups on the preformed addition polymer, and is substantially free of unreacted 1,2-epoxy groups. The ionic polymer component is then dispersed in water with the addition of ammonia or an organic amine neutralizing agent in an amount sufficient to render the composition stably dispersible in water; and an addition polymer different from the addition polymer containing carboxyl groups is incorporated into the aqueous dispersion of said ionic polymer component.
DISPERSIBLE EPOXY RESIN-ACID POLYMER ESTER
ABSTRACT
In a method for preparing a coating composition, an ionic polymer component containing sufficient carboxyl groups to render itself dispersible in water in neutralized form is prepared by reacting an epoxy resin containing 1,2-epoxy groups and an addition polymer containing carboxyl groups such that the resultant ionic polymer contains hydroxy ester groups from the reaction of 1,2-epoxy groups on said epoxy resin with carboxyl groups on the preformed addition polymer, and is substantially free of unreacted 1,2-epoxy groups. The ionic polymer component is then dispersed in water with the addition of ammonia or an organic amine neutralizing agent in an amount sufficient to render the composition stably dispersible in water; and an addition polymer different from the addition polymer containing carboxyl groups is incorporated into the aqueous dispersion of said ionic polymer component.
Description
~Z~L~7~33 PROCESS FOR PREPARING AQUEOUS COATINGS COMPRISING
DISPERSIBLE EPOXY RESIN-ACID POLYMER ESTER
This invention relates to a method for preparing an aqueous coating composition.
A variety of methods for preparing aqueous coating compositions comprising epoxy resins and acrylic polymers are known in the art and several are commercially available. In order to obtain desirable characteristics for many critical end use applications, such as coatings for sanitary cans, it is considered necessary to include a high proportion of epoxy resin in the composition. Epoxy contents of 60 to 80 percent are commonly used.
Typical epoxy acrylate compositions are disclosed in U.S. Patent Nos. 4,247,439, 4,212,781, 4,308,185 and 4,302,373.
U.S. Patent No. 4,285,847 discloses epoxy acrylic compositions in which the epoxy acrylic is made by free-radical grafting of ionizable side chains onto an epoxy backbone; dispersing this product in water and thereafter polymerizing, in situ, addition polymerizable monomers which may or may not also contain ionizable groups. By this means the solids content of the composition is increased and the proportion of total epoxy resin in the composition is reduced by replacement with the cheaper addition polymer thereby reducing the cost of the composition.
The present invention relates to an improved method for preparing an aqueous coating composition which can be conducted in "one pot" or reactor.
Accordingly, the invention resides in a process for preparing an aqueous dispersion composition comprising:
. ~
F-2081 - ~ -A. copolymerizing a monomer mixture which includes at least 30 percent by weight of carboxyl-containing monomer to form a carboxyl containing copolymer in the presence of an epoxy resin con-taining aliphatic carbon atoms and 1,2-epoxy groups in which said epoxy resin constitutes at least 40 weight percent of the solids in the resulting composition;
B. reacting the composition obtained in A
under esterification conditions in the presence of a tertiary amine esterification catalyst wherein the equivalents of 1,2-epoxy groups in said epoxy resin are in excess of the equivalents of tertiary amine, to obtain a product substantially free of epoxy groups and containing hydroxy ester groups from the reaction between said carboxyl group and at least 5 percent of said 1,2-epoxy groups; and C. dispersing said composition in water with the addition of ammonia or amine neutralizing agent;
in which a polymer different from said carboxyl con-taining copolymer of step A is prepared in situ prior to dispersing the mixture in water in step C.
The first step in the process of the invention is the polymerization of a carboxyl containing monomer in the presence of an epoxy resin containing 1,2 epoxy groups to give a mixture of the epoxy resin and a carboxyl containing copolymer. This reaction is a conventional addition polymerization reaction utilizing catalysts and procedures which are well known. For example, the methods disclosed in U.S. Patent 4,212,781 are suitable in which case the resulting mixture presumaoly also contains carboxyl polymer grafted to aliphatic carbon atoms on the epoxy backbone. However, grafting while acceptable herein is not necessary. Accordingly, polymerization conditions less stringent than desired in said patent can be used to obtain a copolymer without any epoxy graft product.
Once the carboxyl containing copolymer is formed the methods disclosed in U.S. Patent 4,247,439 or U.S. Patent 4,302,373 can be used to conduct the reaction between the epoxy resin and the carboxyl containing copolymer. It may, however, be necessary to modify conditions to promote esterification instead of quaternization, for example by using tertiary amine in an amount which is less than sufficient to react with all of the epoxy groups on the epoxy resin.
Briefly, the reaction between the epoxy resin and the preformed addition polymer containing carboxyl groups is conducted in the presence of a tertiary amine, with the conditions being chosen so that an esterification reaction occurs between the epoxy groups of the epoxy resin and the carboxyl groups of the addition polymer. By way of contrast, the reaction conditions in the aforementioned patents are selected in order to promote a reaction between the tertiary amine and epoxy groups giving quaternary ammonium groups in accordance with a well known reaction. It is believed that the reaction which is intended to promote esterification also results in the formation of significant amounts of quaternary ammonium groups by reaction between the epoxy groups and the tertiary amine. Indeed, more of the epoxy groups may be converted to quaternary ammonium groups than are converted to hydroxy ester linkages. Also, the reaction described in said patents intended to produce quaternary ammonium groups can, under appropriate conditions, result in significant ester formation. The products prepared in accordance with the present process therefore can contain significant, even predominant amounts of quaternary groups, providing that hydroxy ester groups obtained by the reaction of epoxy groups ~ith carboxyl groups are also present. At a minimum at least 5 percent of the epoxy groups on the epoxy resin should be converted to hydroxy ester groups. Whatever the relative proportions of quaternary and hydroxy ester groups, the polymer component A is ionic in character and is substantially free of unreacted 1,2-epoxy groups.
1;2~8783 In general, the epoxy resin constitutes at least about 40 percent of the ionic polymer and the carboxyl containing polymer comprises the balance. Preferably the epoxy content is at least 60 percent and most preferably about i5 percent.
A wide variety of epoxy resins may be used herein but the preferred epoxy resins are aromatic polyethers, particularly those derived from the condensation of a bisphenol such as Bisphenol A, and epichlorohydrin. These epoxy resins possess hydroxy groups in addition to epoxy groups. The higher the molecular weight of the epoxy resin the more hydroxy groups are present. These hydroxy groups can participate in the final curiny reaction. The preferred epoxy resins are aromatic polyethers having a number average molecular weight (Mn) of at least 1,500. However, the number average molecular weight of these resins can vary from 350 to 6000.
As recognized in the art, epoxy resins prepared by the condensation of bisphenolsand epichlorohydrin contain a mixture of diepoxides, monoepoxides and aromatic polyethers which are free of epoxy groups. The average functionality of such mixtures may range widely from 0.2 epoxy groups per molecule to nearly 2 epoxy groups per molecule. Suitable mixtures of epoxy resins can be obtained by reacting a lower molecular weight epoxy resin having a functionality of between 1 and 2, for example, with a defunctionalizing agent which is capable of reacting with the epoxy groups. The defunctionalizing agent can contain carboxyl groups, hydroxy groups or amide groups. Speci~ic suitable materials include acids such as benzoic acid and fatty acids such as octanoic acid; hydroxy compounds such as phenols, in particular bisphenols and lo~er alkanols; and amides such as acrylamide. Defunctionalization with bisphenols is of particular interest since the epoxy resin is thereby upgraded to higher molecular weight at the same time as some of the epoxy groups are defunctionalized.
~;~18~83 me OE boxyl-oontaining polymer is prepared by the addition polymerization of ethylenically unsaturated monomers comprlslng a least about 20 percent of an ethylenically unsaturated carboxylic acid based on the total weight of the monomers. Polymers and copolymers of this type are well known although the copolymers with particularly high proportions of carboxylic acid as preferred herein are somewhat unusual. Preferably the carboxyl containing polymer is a copolymer with ethylenically unsaturated monomers which are non-reactive under the contemplated conditions o~ polymerization and reaction with epoxy resin. However, small amounts of reactive monomers, e.g., hydroxy monomers such as 2-hydroxy ethylmethacrylate, amide monomers such as acrylamide, and N-methylol monomers such as N-methylol acrylamide, can be used. Suitable non-reactive monomers are, for example, acrylate and methacrylate esters such as ethyl acrylate, methyl acrylate, butyl acrylate, styrene or vinyl toluene, vinyl acetate, vinyl chloride, vinylidene chloride, and acrylonitrile. The function of these monomers is to enhance solvent solubility and to provide good film formation.
Otherwise the nature and proportions are not critical.
The presence of a large proportion o~ carboxyl functional monomer is important. The preferred minimum proportion of carboxyl monomer is 30 percent of the weight of the monomers used to prepare the carboxyl containing polymer. Methacrylic acid provides the best hydrolytic stability and is very much preferred, but other acids such as fumaric acid, acrylic acid, crotonic acid and itaconic acid are useful. Up to about 80 percent of the monomers can be carboxyl functional, the maximum being determined by retention of solvent solubility of the copolymer.
The preferred polymers containing carboxyl groups generally having a number average molecular weight (Mn) in the range of 3000 to 20,000, preferably 3,0nO to 6,000. Molecular weight can be ~ Z~L8783 controlled by monomer content during polymerization, catalystconcentration and polymerization temperature in known manner.
Mercaptan chain termination is preferably avoided especially where the product is intended for use in coating of sanitary cans because of the offensive odor of mercaptans.
Generally, the addition polymer containing carboxyl groups is reacted with the epoxy resin as a solvent solution in the presence of sufficient amine, preferably tertiary amine to promote the reaction. The preferred esterification catalysts are tertiary amines,particularly dimethylaminoethanol,but other esterification catalysts,particularly tertiary amines such as dimethylbenzylamine, trimethylamine, and tributylamineJcan be used. The amount of catalyst used can vary widely. For example, where a tertiary amine is used as little as 0.1-0.3 percent by weight of the catalyst based on the total amount of epoxy resin and carboxyl containing polymer can be used or the amount can be much larger up to about 10 percent and more of the reactants.
Another way of defining the amount of amine used is the relation to the total carboxyl content of the acid polymer. The amount of amine present during the reaction of the epoxy resin and carboxyl polymer should be sufficient to neutralize from about 5 to about 50 percent of the carboxyl groups in the acid polymer.
Preferably, the amine is sufficient to neutralize between 10 and 35 percent of the carboxyl groups. Still another way of defining the amount of tertiary amine present during reaction of the epoxy resin and carboxyl polymer is by the equivalent ratio of amine to 1,2-epoxy groups. Preferably, this ratio is less than one thereby ensuring that some of the epoxy groups will be consumed in hydroxy ester formation by eaction with carboxyl groups.
The amount of amine has a significant effect on the nature of the product of the reaction. In general, the smaller the amount ~LZ ~L8~33 F-2081 _7_ of amlne present during reaction -the higher the viscoslty of the product. This difference in viscosity is apparent in both the solvent solution and when the product is emulsified in water. The effect of the amount of amine used is observed even where ~he total amount of amine present in the dispersed product is identical.
Thus, for example, the same product is not obtained when amine is present at the 40 percent neutralization level during reaction as when amine su~ficient to neutralize S percent of the carboxyl groups is present during reaction and supplemented with 35 percent of the neutralization amount prior to dispersion in water.
The amount of amine present during reaction also has a pronounced effect on the particle size of the final dispersion.
The second polymer different from the addition polymer used to prepare the ionic epoxy resin-acid polymer product can be prepared from a wide variety of unsaturated monomers. Particularly preferred are monomers which are ~ree of functional groups reactive with epoxy resin or which would render the polymer self-dispersible in water. For example there may be mentioned the esters of acrylic and methacrylic acid such as methyl acrylate, butyl acrylate, methyl methacrylate and butyl methacrylate; aromatic monomers such as styrene and methylstyrene; vinyl and vinylidene halides such as vinyl chloride and vinylidene chloride; isoprene; butadiene; and acrylonitrile. In certain applications it may be advantageous to include in the copolymer self-crosslinking monomers such as N-methylol acrylamide or N-isobutoxy acrylamide. Presently preferred monomers include styrene, methylstyrene and butyl acrylatè.
The second polymer can be introduced at any convenient stage of the reaction. Preferably, the second polymer is prepared, in situ, in the presence of an aqueous dispersion oF the ionic epoxy-acidic polymer reaction product. The reaction is conducted in .
~q~ 3 known manner and advantageously is initiated by a redox system.
Inorganic or organic peroxides such as hydrogen peroxide or t~butyl hydroperoxide; or persulfates such as ammonium persulfate and alkali metal persul~ates can be coupled with a suitable reducing agent such as hydrazine, ammonium or alkali metal sulfites, bisulfites, metabisulfites or hydrosulfites. The procedures disclosed in U.S.
Patent 4,285,847 are suitable for conducting the polymerization.
The second polymer can also be introduced as a preformed polymer into either the aqueous dispersion of the ionic epoxy-acid polymer product or can be mixed with the ionic epoxy resin-acid polymer product before it is dispersed in water. Similarly, the second polymer can be mixed with a solvent solution of the acidic polymer prior to its reaction with the epoxy resin either by making the addition polymers separately or by preparing one in the presence of the other. The second polymer can also be prepared, in situ, in the presence of the epoxy resin either before or after the polymerization of the carboxyl containing polymer has been conducted and either before or after reaction of the carboxyl containing polymer and epoxy resin has taken place. The proportion of the second polymer in the composition can vary widely. The maximum is limited by the amount which can be stably dispersed in water by the ionic polymer component and the retention of desired film properties. Usually the weight ratio of the second addition polymer (B) to the ionic polymer (A) is from 0.05:1 to 10:1 but more preferably is 0.2:1 to 5:1.
The resins used in preparing the compositions of this invention are used by dissolution in a volatile organic solvent. A
wide variety of solvents are suitable. Organic solvents of limited water miscibility, such as xylene, toluene, butanol and
DISPERSIBLE EPOXY RESIN-ACID POLYMER ESTER
This invention relates to a method for preparing an aqueous coating composition.
A variety of methods for preparing aqueous coating compositions comprising epoxy resins and acrylic polymers are known in the art and several are commercially available. In order to obtain desirable characteristics for many critical end use applications, such as coatings for sanitary cans, it is considered necessary to include a high proportion of epoxy resin in the composition. Epoxy contents of 60 to 80 percent are commonly used.
Typical epoxy acrylate compositions are disclosed in U.S. Patent Nos. 4,247,439, 4,212,781, 4,308,185 and 4,302,373.
U.S. Patent No. 4,285,847 discloses epoxy acrylic compositions in which the epoxy acrylic is made by free-radical grafting of ionizable side chains onto an epoxy backbone; dispersing this product in water and thereafter polymerizing, in situ, addition polymerizable monomers which may or may not also contain ionizable groups. By this means the solids content of the composition is increased and the proportion of total epoxy resin in the composition is reduced by replacement with the cheaper addition polymer thereby reducing the cost of the composition.
The present invention relates to an improved method for preparing an aqueous coating composition which can be conducted in "one pot" or reactor.
Accordingly, the invention resides in a process for preparing an aqueous dispersion composition comprising:
. ~
F-2081 - ~ -A. copolymerizing a monomer mixture which includes at least 30 percent by weight of carboxyl-containing monomer to form a carboxyl containing copolymer in the presence of an epoxy resin con-taining aliphatic carbon atoms and 1,2-epoxy groups in which said epoxy resin constitutes at least 40 weight percent of the solids in the resulting composition;
B. reacting the composition obtained in A
under esterification conditions in the presence of a tertiary amine esterification catalyst wherein the equivalents of 1,2-epoxy groups in said epoxy resin are in excess of the equivalents of tertiary amine, to obtain a product substantially free of epoxy groups and containing hydroxy ester groups from the reaction between said carboxyl group and at least 5 percent of said 1,2-epoxy groups; and C. dispersing said composition in water with the addition of ammonia or amine neutralizing agent;
in which a polymer different from said carboxyl con-taining copolymer of step A is prepared in situ prior to dispersing the mixture in water in step C.
The first step in the process of the invention is the polymerization of a carboxyl containing monomer in the presence of an epoxy resin containing 1,2 epoxy groups to give a mixture of the epoxy resin and a carboxyl containing copolymer. This reaction is a conventional addition polymerization reaction utilizing catalysts and procedures which are well known. For example, the methods disclosed in U.S. Patent 4,212,781 are suitable in which case the resulting mixture presumaoly also contains carboxyl polymer grafted to aliphatic carbon atoms on the epoxy backbone. However, grafting while acceptable herein is not necessary. Accordingly, polymerization conditions less stringent than desired in said patent can be used to obtain a copolymer without any epoxy graft product.
Once the carboxyl containing copolymer is formed the methods disclosed in U.S. Patent 4,247,439 or U.S. Patent 4,302,373 can be used to conduct the reaction between the epoxy resin and the carboxyl containing copolymer. It may, however, be necessary to modify conditions to promote esterification instead of quaternization, for example by using tertiary amine in an amount which is less than sufficient to react with all of the epoxy groups on the epoxy resin.
Briefly, the reaction between the epoxy resin and the preformed addition polymer containing carboxyl groups is conducted in the presence of a tertiary amine, with the conditions being chosen so that an esterification reaction occurs between the epoxy groups of the epoxy resin and the carboxyl groups of the addition polymer. By way of contrast, the reaction conditions in the aforementioned patents are selected in order to promote a reaction between the tertiary amine and epoxy groups giving quaternary ammonium groups in accordance with a well known reaction. It is believed that the reaction which is intended to promote esterification also results in the formation of significant amounts of quaternary ammonium groups by reaction between the epoxy groups and the tertiary amine. Indeed, more of the epoxy groups may be converted to quaternary ammonium groups than are converted to hydroxy ester linkages. Also, the reaction described in said patents intended to produce quaternary ammonium groups can, under appropriate conditions, result in significant ester formation. The products prepared in accordance with the present process therefore can contain significant, even predominant amounts of quaternary groups, providing that hydroxy ester groups obtained by the reaction of epoxy groups ~ith carboxyl groups are also present. At a minimum at least 5 percent of the epoxy groups on the epoxy resin should be converted to hydroxy ester groups. Whatever the relative proportions of quaternary and hydroxy ester groups, the polymer component A is ionic in character and is substantially free of unreacted 1,2-epoxy groups.
1;2~8783 In general, the epoxy resin constitutes at least about 40 percent of the ionic polymer and the carboxyl containing polymer comprises the balance. Preferably the epoxy content is at least 60 percent and most preferably about i5 percent.
A wide variety of epoxy resins may be used herein but the preferred epoxy resins are aromatic polyethers, particularly those derived from the condensation of a bisphenol such as Bisphenol A, and epichlorohydrin. These epoxy resins possess hydroxy groups in addition to epoxy groups. The higher the molecular weight of the epoxy resin the more hydroxy groups are present. These hydroxy groups can participate in the final curiny reaction. The preferred epoxy resins are aromatic polyethers having a number average molecular weight (Mn) of at least 1,500. However, the number average molecular weight of these resins can vary from 350 to 6000.
As recognized in the art, epoxy resins prepared by the condensation of bisphenolsand epichlorohydrin contain a mixture of diepoxides, monoepoxides and aromatic polyethers which are free of epoxy groups. The average functionality of such mixtures may range widely from 0.2 epoxy groups per molecule to nearly 2 epoxy groups per molecule. Suitable mixtures of epoxy resins can be obtained by reacting a lower molecular weight epoxy resin having a functionality of between 1 and 2, for example, with a defunctionalizing agent which is capable of reacting with the epoxy groups. The defunctionalizing agent can contain carboxyl groups, hydroxy groups or amide groups. Speci~ic suitable materials include acids such as benzoic acid and fatty acids such as octanoic acid; hydroxy compounds such as phenols, in particular bisphenols and lo~er alkanols; and amides such as acrylamide. Defunctionalization with bisphenols is of particular interest since the epoxy resin is thereby upgraded to higher molecular weight at the same time as some of the epoxy groups are defunctionalized.
~;~18~83 me OE boxyl-oontaining polymer is prepared by the addition polymerization of ethylenically unsaturated monomers comprlslng a least about 20 percent of an ethylenically unsaturated carboxylic acid based on the total weight of the monomers. Polymers and copolymers of this type are well known although the copolymers with particularly high proportions of carboxylic acid as preferred herein are somewhat unusual. Preferably the carboxyl containing polymer is a copolymer with ethylenically unsaturated monomers which are non-reactive under the contemplated conditions o~ polymerization and reaction with epoxy resin. However, small amounts of reactive monomers, e.g., hydroxy monomers such as 2-hydroxy ethylmethacrylate, amide monomers such as acrylamide, and N-methylol monomers such as N-methylol acrylamide, can be used. Suitable non-reactive monomers are, for example, acrylate and methacrylate esters such as ethyl acrylate, methyl acrylate, butyl acrylate, styrene or vinyl toluene, vinyl acetate, vinyl chloride, vinylidene chloride, and acrylonitrile. The function of these monomers is to enhance solvent solubility and to provide good film formation.
Otherwise the nature and proportions are not critical.
The presence of a large proportion o~ carboxyl functional monomer is important. The preferred minimum proportion of carboxyl monomer is 30 percent of the weight of the monomers used to prepare the carboxyl containing polymer. Methacrylic acid provides the best hydrolytic stability and is very much preferred, but other acids such as fumaric acid, acrylic acid, crotonic acid and itaconic acid are useful. Up to about 80 percent of the monomers can be carboxyl functional, the maximum being determined by retention of solvent solubility of the copolymer.
The preferred polymers containing carboxyl groups generally having a number average molecular weight (Mn) in the range of 3000 to 20,000, preferably 3,0nO to 6,000. Molecular weight can be ~ Z~L8783 controlled by monomer content during polymerization, catalystconcentration and polymerization temperature in known manner.
Mercaptan chain termination is preferably avoided especially where the product is intended for use in coating of sanitary cans because of the offensive odor of mercaptans.
Generally, the addition polymer containing carboxyl groups is reacted with the epoxy resin as a solvent solution in the presence of sufficient amine, preferably tertiary amine to promote the reaction. The preferred esterification catalysts are tertiary amines,particularly dimethylaminoethanol,but other esterification catalysts,particularly tertiary amines such as dimethylbenzylamine, trimethylamine, and tributylamineJcan be used. The amount of catalyst used can vary widely. For example, where a tertiary amine is used as little as 0.1-0.3 percent by weight of the catalyst based on the total amount of epoxy resin and carboxyl containing polymer can be used or the amount can be much larger up to about 10 percent and more of the reactants.
Another way of defining the amount of amine used is the relation to the total carboxyl content of the acid polymer. The amount of amine present during the reaction of the epoxy resin and carboxyl polymer should be sufficient to neutralize from about 5 to about 50 percent of the carboxyl groups in the acid polymer.
Preferably, the amine is sufficient to neutralize between 10 and 35 percent of the carboxyl groups. Still another way of defining the amount of tertiary amine present during reaction of the epoxy resin and carboxyl polymer is by the equivalent ratio of amine to 1,2-epoxy groups. Preferably, this ratio is less than one thereby ensuring that some of the epoxy groups will be consumed in hydroxy ester formation by eaction with carboxyl groups.
The amount of amine has a significant effect on the nature of the product of the reaction. In general, the smaller the amount ~LZ ~L8~33 F-2081 _7_ of amlne present during reaction -the higher the viscoslty of the product. This difference in viscosity is apparent in both the solvent solution and when the product is emulsified in water. The effect of the amount of amine used is observed even where ~he total amount of amine present in the dispersed product is identical.
Thus, for example, the same product is not obtained when amine is present at the 40 percent neutralization level during reaction as when amine su~ficient to neutralize S percent of the carboxyl groups is present during reaction and supplemented with 35 percent of the neutralization amount prior to dispersion in water.
The amount of amine present during reaction also has a pronounced effect on the particle size of the final dispersion.
The second polymer different from the addition polymer used to prepare the ionic epoxy resin-acid polymer product can be prepared from a wide variety of unsaturated monomers. Particularly preferred are monomers which are ~ree of functional groups reactive with epoxy resin or which would render the polymer self-dispersible in water. For example there may be mentioned the esters of acrylic and methacrylic acid such as methyl acrylate, butyl acrylate, methyl methacrylate and butyl methacrylate; aromatic monomers such as styrene and methylstyrene; vinyl and vinylidene halides such as vinyl chloride and vinylidene chloride; isoprene; butadiene; and acrylonitrile. In certain applications it may be advantageous to include in the copolymer self-crosslinking monomers such as N-methylol acrylamide or N-isobutoxy acrylamide. Presently preferred monomers include styrene, methylstyrene and butyl acrylatè.
The second polymer can be introduced at any convenient stage of the reaction. Preferably, the second polymer is prepared, in situ, in the presence of an aqueous dispersion oF the ionic epoxy-acidic polymer reaction product. The reaction is conducted in .
~q~ 3 known manner and advantageously is initiated by a redox system.
Inorganic or organic peroxides such as hydrogen peroxide or t~butyl hydroperoxide; or persulfates such as ammonium persulfate and alkali metal persul~ates can be coupled with a suitable reducing agent such as hydrazine, ammonium or alkali metal sulfites, bisulfites, metabisulfites or hydrosulfites. The procedures disclosed in U.S.
Patent 4,285,847 are suitable for conducting the polymerization.
The second polymer can also be introduced as a preformed polymer into either the aqueous dispersion of the ionic epoxy-acid polymer product or can be mixed with the ionic epoxy resin-acid polymer product before it is dispersed in water. Similarly, the second polymer can be mixed with a solvent solution of the acidic polymer prior to its reaction with the epoxy resin either by making the addition polymers separately or by preparing one in the presence of the other. The second polymer can also be prepared, in situ, in the presence of the epoxy resin either before or after the polymerization of the carboxyl containing polymer has been conducted and either before or after reaction of the carboxyl containing polymer and epoxy resin has taken place. The proportion of the second polymer in the composition can vary widely. The maximum is limited by the amount which can be stably dispersed in water by the ionic polymer component and the retention of desired film properties. Usually the weight ratio of the second addition polymer (B) to the ionic polymer (A) is from 0.05:1 to 10:1 but more preferably is 0.2:1 to 5:1.
The resins used in preparing the compositions of this invention are used by dissolution in a volatile organic solvent. A
wide variety of solvents are suitable. Organic solvents of limited water miscibility, such as xylene, toluene, butanol and
2-butoxyethanol are useful, and they may be used alone or together with water miscible solvents, such as 2-ethoxyethanol or methyl ethyl ketone.
~z~a~3 The final composition includes suf~icient ammonia or amine to render the mixture sel~-dispersible in water. Preferably, a tertiary amine such as dimethylethanolamine is used. In general, the total amount of an amine or an ammonia present in the final product will be sufficient to neutralize at least 25 to 90 percent of the carboxyl groups present in the polymers used to prepare their composition. Finally, compositions, as used, preferably include a curing agent such as an aminoplast or a phenoplast resin in an amount o~ 1 to 25 percent, preferably from 3 to 10 percent, based on the solids o~ the composition.
~z~a~3 The final composition includes suf~icient ammonia or amine to render the mixture sel~-dispersible in water. Preferably, a tertiary amine such as dimethylethanolamine is used. In general, the total amount of an amine or an ammonia present in the final product will be sufficient to neutralize at least 25 to 90 percent of the carboxyl groups present in the polymers used to prepare their composition. Finally, compositions, as used, preferably include a curing agent such as an aminoplast or a phenoplast resin in an amount o~ 1 to 25 percent, preferably from 3 to 10 percent, based on the solids o~ the composition.
Claims (15)
1. A process for preparing an aqueous dispersion composition comprising:
A. copolymerizing a monomer mixture which includes at least 30 percent by weight of carboxyl-containing monomer to form a carboxyl containing copolymer in the presence of an epoxy resin con-taining aliphatic carbon atoms and 1,2-epoxy groups in which said epoxy resin constitutes at least 40 weight percent of the solids in the resulting composition;
B. reacting the composition obtained in A
under esterification conditions in the presence of a tertiary amine esterification catalyst wherein the equivalents of 1,2-epoxy groups in said epoxy resin are in excess of the equivalents of tertiary amine, to obtain a product substantially free of epoxy groups and containing hydroxy ester groups from the reaction between said carboxyl group and at least 5 percent of said 1,2-epoxy groups; and C. dispersing said composition in water with the addition of ammonia or amine neutralizing agent; in which a polymer different from said carboxyl containing copolymer of step A is prepared in situ prior to dispersing the mixture in water in step C.
A. copolymerizing a monomer mixture which includes at least 30 percent by weight of carboxyl-containing monomer to form a carboxyl containing copolymer in the presence of an epoxy resin con-taining aliphatic carbon atoms and 1,2-epoxy groups in which said epoxy resin constitutes at least 40 weight percent of the solids in the resulting composition;
B. reacting the composition obtained in A
under esterification conditions in the presence of a tertiary amine esterification catalyst wherein the equivalents of 1,2-epoxy groups in said epoxy resin are in excess of the equivalents of tertiary amine, to obtain a product substantially free of epoxy groups and containing hydroxy ester groups from the reaction between said carboxyl group and at least 5 percent of said 1,2-epoxy groups; and C. dispersing said composition in water with the addition of ammonia or amine neutralizing agent; in which a polymer different from said carboxyl containing copolymer of step A is prepared in situ prior to dispersing the mixture in water in step C.
2. The process of claim 1 in which said different polymer is substantially free of carboxylic acid groups.
3. The process of claim 1 in which said different polymer is a copolymer of styrene and butyl acrylate.
4. The process of claim 1 in which said carboxyl containing monomer is methacrylic acid.
5. The process of claim 1 in which said carboxyl containing copolymer is a copolymer of ethyl acrylate, styrene and methacrylic acid.
6. The process of claim 1 in which said epoxy resin is an epichlorohydrin-bisphenol A epoxy resin.
7. The process of claim 1 in which said tertiary amine and said neutralizing agent are dimethylaminoethanol.
8. The process of claim 1 in which said copolymerization in step A is conducted under conditions which result in grafting of said carboxyl containing copolymer to aliphatic carbon atoms on said epoxy resin.
9. The process of claim 1 in which copolymerization in step A is conducted under conditions which result in substantially no grafting of said carboxyl containing polymer to aliphatic carbon atoms on said epoxy resin.
10. The process of claim 1 in which said epoxy resin is an epichlorohydrin-bisphenol A epoxy resin; said carboxyl containing copolymer is a copolymer of ethyl acrylate, styrene and methacrylic acid; and said tertiary amine and said neutralizing agent are dimethylaminoethanol.
11. The process of claim 10 in which the weight ratio of said epoxy resin to said carboxyl containing polymer is at least 1:1.
12. The process of claim 10 in which the weight ratio of said epoxy resin to said carboxyl containing polymer is at least 2:1.
13. The process of claim 10 in which the weight ratio of said epoxy resin to said carboxyl containing polymer is at least 3:1.
14. The process of claim 10 in which said copolymerization in step A is conducted under conditions which result in grafting of said carboxyl containing copolymer to aliphatic carbon atoms on said epoxy resin.
15. The process of claim 10 in which copolymerization in step A is conducted under conditions which result in substantially no grafting of said carboxyl containing polymer to aliphatic carbon atoms on said epoxy resin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US454,817 | 1982-12-30 | ||
| US06/454,817 US4444923A (en) | 1982-12-30 | 1982-12-30 | Process for preparing aqueous coatings comprising dispersible epoxy resin-acid polymer ester |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1218783A true CA1218783A (en) | 1987-03-03 |
Family
ID=23806239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000443447A Expired CA1218783A (en) | 1982-12-30 | 1983-12-15 | Process for preparing aqueous coatings comprising dispersible epoxy resin-acid polymer ester |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4444923A (en) |
| CA (1) | CA1218783A (en) |
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| JPS60501363A (en) * | 1983-07-25 | 1985-08-22 | ザ・ダウ・ケミカル・カンパニ− | Stable organic polymer dispersions in polyepoxides and methods of making such dispersions |
| US4789712A (en) * | 1983-07-25 | 1988-12-06 | The Dow Chemical Company | Stable dispersions of polymers in polyepoxides |
| US4708996A (en) * | 1983-07-25 | 1987-11-24 | The Dow Chemical Company | Stable dispersions of polymers in polyepoxides |
| US4600737A (en) * | 1983-12-21 | 1986-07-15 | Inmont Corporation | Water dilutable acrylated epoxy-phenolic coating compositions |
| US4579888A (en) * | 1984-04-10 | 1986-04-01 | Toyo Ink Manufacturing Co., Ltd. | Aqueous resin dispersion |
| JPS60239566A (en) * | 1984-05-14 | 1985-11-28 | 花王株式会社 | Fiber treating agent and fiber treatment using the same |
| ZA854883B (en) * | 1984-08-27 | 1986-04-30 | Dulux Australia Ltd | Coating compositions |
| US4564648A (en) * | 1984-09-21 | 1986-01-14 | E. I. Du Pont De Nemours And Company | Epoxy graft acrylic water-based primer surfaces |
| US4690988A (en) * | 1985-01-22 | 1987-09-01 | The Dow Chemical Company | Polymer-modified vinylized epoxy resins |
| US4588757A (en) * | 1985-02-11 | 1986-05-13 | Desoto, Inc. | Aqueous emulsion laminating adhesive |
| US4579887A (en) * | 1985-02-26 | 1986-04-01 | The Dow Chemical Company | Non-aqueous dispersions of relatively high molecular weight epoxy resins |
| DE3544337A1 (en) * | 1985-12-14 | 1987-06-19 | Hoechst Ag | POLYMERISAT DISPERSIONS, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE AS BINDERS |
| DE3627860A1 (en) * | 1986-08-16 | 1988-02-18 | Basf Lacke & Farben | AQUEOUS COATING AGENT, METHOD FOR THE PRODUCTION THEREOF AND ITS USE FOR COATING CAN |
| MX169357B (en) * | 1987-08-13 | 1993-09-30 | Valspar Corp | COATING COMPOSITION IN AQUEOUS COMPOSITION |
| US4889890A (en) * | 1987-12-30 | 1989-12-26 | Ppg Industries, Inc. | Powder coating curing system containing a beta-hydroxyalkylamide |
| US5013791A (en) * | 1987-12-30 | 1991-05-07 | Ppg Industries, Inc. | Beta-hydroxyalkylamide cured acid polymer/polyepoxide powder coating |
| US5043366A (en) * | 1989-02-20 | 1991-08-27 | Kansai Paint Co., Ltd. | Self-curing aqueous resin dispersion based on alicyclic epoxies |
| US5204386A (en) * | 1990-11-13 | 1993-04-20 | The Dow Chemical Company | Acrylic-modified epoxy resin adhesive compositions with improved rheological control |
| US5290828A (en) * | 1993-06-11 | 1994-03-01 | The Glidden Company | Aqueous dispersed acrylic grafted epoxy polyester protective coatings |
| US5527840B1 (en) * | 1994-10-04 | 1999-08-10 | Valspar Corp | Aqueous coating composition |
| US5830952A (en) * | 1996-02-22 | 1998-11-03 | The Dexter Corporation | Water-dispersible polymer and coating composition containing the same |
| US5686511A (en) * | 1996-06-28 | 1997-11-11 | The Valspar Corporation | Esterifying epoxy resin with carboxyl polymer and quenching |
| US6008273A (en) * | 1997-05-09 | 1999-12-28 | The Dexter Corporation | Waterborne coating compositions for metal containers |
| EP0919595B1 (en) * | 1997-06-19 | 2006-04-26 | Mitsui Chemicals, Inc. | Molding resin composition |
| US6194510B1 (en) * | 1997-11-12 | 2001-02-27 | S. C. Johnson Commercial Markets, Inc. | Aqueous dispersions of non-gelled polymeric compositions having designated amounts of reactive groups |
| US6087417A (en) * | 1998-01-16 | 2000-07-11 | The Valspar Corporation | Epoxy resin/acid/tertiary amine reaction product with reactive diluent |
| US6379813B1 (en) | 1999-09-17 | 2002-04-30 | S. C. Johnson Commercial Markets, Inc. | Pigmented compositions and articles of manufacture containing same |
| AU2000275966A1 (en) * | 2000-09-20 | 2002-04-02 | Johnson Polymer, Inc. | Pigmented compositions and articles of manufacture containing same |
| BRPI0408909B1 (en) | 2003-04-02 | 2016-08-02 | Valspar Sourcing Inc | method for forming a dispersion, composition, method for coating an article, and, article |
| CA2507779C (en) * | 2004-05-21 | 2012-01-31 | National Research Council Of Canada | Primer composition and uses thereof |
| EP1819789B1 (en) | 2004-10-20 | 2011-06-15 | Valspar Sourcing, Inc. | Coating compositions for cans and methods of coating |
| EP2416962B1 (en) | 2009-04-09 | 2016-08-10 | Valspar Sourcing, Inc. | Polymer having unsaturated cycloaliphatic functionality and coating compositions formed therefrom |
| US8486574B2 (en) * | 2009-07-14 | 2013-07-16 | Ford Global Technologies, Llc | Method and system for power control in an automotive vehicle |
| EP3208289A1 (en) | 2009-07-17 | 2017-08-23 | Valspar Sourcing, Inc. | Coating composition and articles coated therewith |
| US8754614B2 (en) * | 2009-07-17 | 2014-06-17 | Tesla Motors, Inc. | Fast charging of battery using adjustable voltage control |
| BR112012006030A2 (en) | 2009-09-18 | 2016-03-22 | Valspar Sourcing Inc | method coated article and composition |
| EP2476673A1 (en) | 2010-12-27 | 2012-07-18 | Cytec Surface Specialties, S.A. | Radiation curable compositions and compounds |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2954358A (en) * | 1957-10-01 | 1960-09-27 | Rohm & Haas | Aqueous dispersion containing acrylic acid copolymer and aliphatic polyepoxide |
| US4247439A (en) * | 1973-11-06 | 1981-01-27 | E. I. Du Pont De Nemours And Company | Water-borne coating composition made from epoxy resin, polymeric acid and tertiary amine |
| US4029620A (en) * | 1975-08-13 | 1977-06-14 | Mobil Oil Corporation | Blends of partially neutralized carboxyl functional copolymers and epoxy resins in aqueous emulsion |
| US4308185A (en) * | 1976-05-11 | 1981-12-29 | Scm Corporation | Graft polymer compositions of terminated epoxy resin, processes for making and using same, and substrates coated therewith |
| US4212781A (en) * | 1977-04-18 | 1980-07-15 | Scm Corporation | Modified epoxy resins, processes for making and using same and substrates coated therewith |
| CA1186846A (en) * | 1978-06-12 | 1985-05-07 | George L. Brown | Aqueous emulsion coatings composition comprising self-emulsifiable epoxy ester copolymer mixture |
| CA1183641A (en) * | 1978-06-12 | 1985-03-05 | George L. Brown | Production of self-emulsifiable epoxy ester copolymer mixtures |
| US4285847A (en) * | 1979-04-11 | 1981-08-25 | Scm Corporation | Polymerization process and product |
| US4399241A (en) * | 1980-03-21 | 1983-08-16 | Scm Corporation | Base for a graft polymer, novel graft polymer compositions, solvents and water-reducible coatings incorporating the novel graft polymers, and processes for making them |
| US4302373A (en) * | 1980-08-05 | 1981-11-24 | E. I. Du Pont De Nemours And Company | Water-borne coating composition made from modified epoxy resin, polymeric acid and tertiary amine |
| US4383059A (en) * | 1980-10-06 | 1983-05-10 | The International Paint Company Limited | Water dilutable epoxy coating compositions |
| US4374875A (en) * | 1980-12-15 | 1983-02-22 | Union Carbide Corporation | Water-borne thermoplastic polyhydroxyether compositions |
| US4341682A (en) * | 1980-12-23 | 1982-07-27 | Mobil Oil Corporation | Composition comprising ester of epoxy, carbonyl containing polybutadiene polymer and acid containing addition polymer, and aqueous coating compositions prepared therefrom |
-
1982
- 1982-12-30 US US06/454,817 patent/US4444923A/en not_active Expired - Lifetime
-
1983
- 1983-12-15 CA CA000443447A patent/CA1218783A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4444923A (en) | 1984-04-24 |
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