JP3624251B2 - Heat resistant water film forming resin composition - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition for forming a hot water-resistant film, and more specifically, uses such as paints, printing inks, paper and plastic coating agents, binders for fibers, and polymer cross-linking agents having reactive groups that require hot water resistance. It is related with the aqueous resin composition useful for.
[0002]
[Prior art]
Conventionally, water-based resin compositions such as water-based paints and water-based printing inks have been studied as an alternative to solvent systems from the viewpoint of ease of handling and safety. However, in the case of an aqueous system, the resin itself is water-soluble or is used as an aqueous dispersion using an emulsifier or the like, so that it has a drawback of poor water resistance.
[0003]
Originally, it is a contradictory requirement to form a water-resistant film with a water-soluble or water-dispersible resin, and it is extremely difficult to produce a water-resistant resin film that satisfies these conflicting requirements.
[0004]
For this reason, for the purpose of improving water resistance, there are self-crosslinking resins in which reactive groups that react with each other are introduced into the polymer chain, and crosslinkers that crosslink the reactive groups introduced in the side chains with a crosslinking agent. Many have been proposed. For example, a method in which hexamethoxymethylol melamine is blended in a water-soluble polyester resin and baked for 20 to 30 minutes is mentioned. In this case, a long baking time is required, and other methods are also immersed in hot water for a long time. In some cases, there is a drawback that whitening, dissolution, peeling from the substrate, and the like occur.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to solve the problem of poor water resistance, which is a drawback of aqueous resins, and to form a composition that forms a resin film that does not change in whitening, dissolution, etc. even when immersed in hot water for a long time. There is to get.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is, the composition of the present invention has a molecular weight of 2,000 to 30,000 and a glycidyl group-containing radical polymerizable vinyl monomer in an aqueous solution or dispersion of a polyester resin containing a carboxylate salt in an amount of 20 to 100% by weight. And a modified polyester resin (A) obtained by polymerizing 80 to 0% by weight of another radical polymerizable vinyl monomer, and an epoxy group-containing crosslinking agent (B) having two or more epoxy groups in one molecule (hereinafter referred to as epoxy) The compounding ratio is a ratio Y / X of the equivalent (X) of the carboxyl group of the modified polyester resin (A) and the equivalent (Y) of the epoxy group of the epoxy crosslinking agent (B). Is a resin composition of 0.2-5.
[0007]
The polyester resin used for the production of the modified polyester resin (A) must have a molecular weight of 2,000 to 30,000 and contain a carboxylate. When the molecular weight is 2,000 or less, the resin physical properties such as water resistance, blocking resistance and adhesion are deteriorated. When the molecular weight is 30,000 or more, the resin is difficult to disperse in water or stable even if it can be dispersed. Only bad ones can be obtained.
The preferred molecular weight is 2,500 to 25,000.
[0008]
The carboxylate is a free carboxylate separated from the polyester main chain, and is a salt with a substance that forms a water-soluble salt with a compound such as an alkali metal, various amines, and an ammonium compound.
[0009]
The best results are obtained when the amount of carboxylate in the polyester resin is such that the acid value of the produced polyester resin is between 15 and 250 KOHmg / g. If the acid value is 15 or less, it is difficult to disperse the polyester resin in water and the water resistance of the resin is poor. If the acid value is 250 or more, the water resistance is poor.
[0010]
The carboxylate-containing polyester resin used as the raw material of the modified polyester resin (A) is, for example, a trifunctional or higher polyvalent carboxylic acid as a condensed acid component at the time of production of the polyester resin, or polymerizable unsaturated in the polyester resin. A method of graft polymerization of a carboxylic acid, or a method of extending a chain by a selective monoesterification reaction of a glycol or a polyester glycol having a hydroxyl group at a terminal and a tetracarboxylic dianhydride as disclosed in JP-A-62-240318 There is.
[0011]
Examples of the dicarboxylic acid used in the production of the carboxylate-containing polyester resin include terephthalic acid, isophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2 -Dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarponic acid, 1,4-cyclohexanedicarboxylic acid, 2,5 -Norbornane dicarboxylic acid, 1,4-naphthalic acid, diphenic acid, 4,4'-oxybenzoic acid, diglycolic acid, thiodipropionic acid, and 2,5-naphthalenedicarboxylic acid. In addition, as sulfonic acid group-containing dicarboxylic acids, metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5 [4-sulfophenoxy] isophthalic acid are used. Can be mentioned.
[0012]
Further, when a trivalent or higher polyvalent carboxylic acid is used in combination, examples of the polyvalent carboxylic acid include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3. A tricarboxylic acid anhydride, trimesic acid, etc. can be mentioned.
[0013]
Examples of the dihydric alcohol used in the carboxylate-containing polyester resin include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2, 2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3- Butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclo Cyclohexanedicarboxylic methanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and the like.
[0014]
Further, not only dihydric alcohols but also diphenols can be used. Examples thereof include 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4 '-(2-norbornylidene) diphenol, 4,4'-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4'-isopropylidenephenol, 4,4'-isopropylidenebis (2,6-dichlorophenol) 2,5-naphthalene Diol and p-xylene diol are mentioned.
[0015]
In addition to the above, a trihydric or higher polyhydric alcohol such as pentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol and the like can be used if the amount is small.
[0016]
In order to produce the carboxylate-containing polyester resin, a polyvalent carboxylic acid or a salt thereof, an ester and a polyhydric alcohol or a polyphenol are esterified or transesterified according to a conventional method, and the product is compressed under vacuum as necessary. Polymerize.
[0017]
The carboxylate-containing polyester resin is made into an aqueous dispersion, and the means is to dissolve or disperse the resin in an aqueous solution of an alkaline compound such as aqueous ammonia, sodium hydroxide, potassium hydroxide, and various amines with stirring. . In this case, a water-soluble organic solvent such as methanol, ethanol, isopropanol, butyl cellosolve, or ethyl cellosolve may be used in combination in order to facilitate dissolution or dispersion of the resin.
[0018]
Next, examples of the glycidyl group-containing radical polymerizable vinyl monomer used in the present invention include glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether.
[0019]
The above glycidyl group-containing radical polymerizable vinyl monomer may be used in combination with another vinyl monomer for copolymerization. Other vinyl monomers used in combination include vinyl ester, unsaturated carboxylic acid ester, unsaturated carboxylic acid amide, unsaturated nitrile, unsaturated carboxylic acid, allyl compound, nitrogen-containing vinyl monomer, hydrocarbon vinyl monomer or vinyl silane compound. Can be mentioned.
[0020]
Examples of vinyl esters include vinyl propionate, vinyl stearate, higher tertiary vinyl esters, vinyl chloride, and vinyl bromide.
Examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, butyl maleate, octyl maleate, butyl fumarate, Octyl fumarate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, Examples thereof include polyethylene glycol dimethacrylate and polyethylene glycol diacrylate.
[0021]
Examples of unsaturated carboxylic acid amides include acrylamide, methacrylamide, methylol acrylamide, and butoxymethylol acrylamide.
An example of the unsaturated nitrile is acrylonitrile.
Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic acid acidic ester, fumaric acid acidic ester, and itaconic acid acidic ester.
[0022]
Examples of the allyl compound include allyl acetate, allyl methacrylate, allyl acrylate, and diallyl itaconate.
Examples of the nitrogen-containing vinyl monomer include vinyl pyridine and vinyl imidazole, and examples of the hydrocarbon vinyl monomer include ethylene, propylene, hexene, octene, styrene, vinyl toluene, and butadiene.
Examples of the vinylsilane compound include dimethylvinylmethoxysilane, dimethylvinylethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyldimethoxysilane.
[0023]
When water-soluble monomers such as hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, polyethylene glycol dimethacrylate, acrylamide, methacrylamide, acrylic acid, methacrylic acid are used as radical polymerizable monomers A composition capable of forming a hydrophilic and hot water-resistant film is obtained, and the features of the present invention are further exhibited.
[0024]
The glycidyl group-containing vinyl monomer needs to be 20% by weight or more in the radical polymerizable vinyl monomer. If it is less than 20% by weight, the hot water resistance tends to be inferior.
The ratio of the carboxylic acid-containing polyester resin and the radical polymerizable vinyl monomer used is 95: 5 to 20:80, preferably 90:10 to 40:60, in terms of resin solids weight ratio. When the weight ratio is 95: 5 or less, sufficient hot water resistance cannot be obtained, and when it exceeds 20:80, the adhesion to the substrate is remarkably lowered.
[0025]
The modified polyester resin can be produced, for example, by adding a polymerization initiator and, if necessary, a small amount of an emulsifying dispersant in a 5 to 30% by weight aqueous dispersion of the carboxylate-containing polyester resin, and maintaining the temperature at 70 to 80 ° C. The radical polymerizable vinyl monomer is gradually added while stirring, and then aged for 2 to 5 hours to complete the polymerization to obtain an aqueous dispersion of the modified polyester resin. The resulting aqueous dispersion is a mixture of radical polymer grafted polyester resin, polyester and radical polymer. It was found that a modified polyester resin aqueous dispersion having a very high graft ratio can be obtained by the method of the present invention. The reason for this seems to be largely due to the reaction between the carboxyl group of the polyester resin and the glycidyl group of the glycidyl group-containing vinyl monomer.
[0026]
As a polymerization initiator, a general radical polymerization initiator, for example, a water-soluble peroxide such as potassium persulfate, ammonium persulfate or hydrogen peroxide, or an oil-soluble peroxide such as benzoyl peroxide or t-butyl hydroperoxide Alternatively, azo compounds such as azodiisobutyronitrile can be used.
[0027]
The resin composition of the present invention is obtained by further blending an epoxy crosslinking agent with the modified polyester resin.
It is considered that the epoxy group of the epoxy crosslinking agent reacts with the carboxyl group in the modified polyester resin molecule by heat treatment to form a crosslinked structure. Therefore, the epoxy crosslinking agent used in the present invention has two or more epoxy groups in one molecule. It is essential.
[0028]
Examples of the epoxy crosslinking agent having two or more epoxy groups in one molecule include glycerol diglycidyl ether, glycerol triglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and ethylene propylene glycol diglycidyl ether. Sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, diglycerol polyglycidyl ether, adipic acid diglycidyl ester, and the like, but are not limited thereto.
[0029]
The blending ratio of the modified polyester resin and the epoxy crosslinking agent is best when the equivalent of the epoxy group of the epoxy crosslinking agent is between 0.2 and 5 and preferably between 0.5 and 2 with respect to the carboxyl group of the polyester resin. Results are obtained. When it is 0.2 or less, sufficient hot water resistance is not obtained, and when it is 5 or more, adhesion to a plastic such as a polyester film is lowered.
[0030]
The resin composition obtained in this manner is heated and dried, and more preferably, for example, by performing a heat treatment at 150 to 180 ° C. for several minutes, crosslinking inside the resin further proceeds and heat resistant water performance is obtained. For printing ink, polyester, polypropylene, ABS, polystyrene, polyvinyl chloride and other plastics, metals, paper coatings, light scattering and light transmissive coatings, rust prevention coatings, fiber binders, reactions It is useful for applications such as a polymer crosslinking agent having a group.
[0031]
Hereinafter, the present invention will be described in more detail with reference to examples and production examples. In addition, the part in a manufacture example and an Example shows a weight part.
[Production Example 1] Production of carboxylic acid-containing polyester resin 1163 parts of isophthalic acid, 217 parts of ethylene glycol, 365 parts of neopentyl glycol, 94 parts of trimethylolpropane, together with 0.78 parts of dibutyltin oxide as a catalyst, a nitrogen introduction tube and a thermometer Then, the mixture was charged into a reactor equipped with a stirrer and a rectifying column, and an esterification reaction was performed at 190 to 230 ° C. under normal pressure for 3 hours. Subsequently, 362 parts of trimellitic acid was added at 170 to 190 ° C., and an addition reaction was carried out for 2 hours to obtain a polyester resin (A-1) having a molecular weight of 2780 and an acid value of 108 KOHmg / g.
[0032]
Production Example 2 Production of Carboxylic Acid-Containing Polyester Resin 115 parts of dimethyl terephthalate, 75 parts of dimethyl isophthalate, 71 parts of ethylene glycol, 110 parts of neopentyl glycol, 0.1 parts of zinc acetate and 0.1 part of antimony trioxide At the same time, the same reactor as in Production Example 1 was charged and a transesterification reaction was carried out at 140 to 220 ° C. over 3 hours. Subsequently, a polycondensation reaction was performed at 240 to 270 ° C. under reduced pressure (10 to 0.2 mmHg) over 30 minutes. Next, 15 parts of trimellitic anhydride was added at 170 to 190 ° C. under normal pressure, and an addition reaction was performed for 30 minutes to obtain a polyester resin (A-2) having a molecular weight of 5700 and an acid value of 42 KOHmg / g.
[0033]
[Production Example 3] Production of carboxylic acid-containing polyester resin 83 parts of terephthalic acid, 83 parts of isophthalic acid, 62 parts of ethylene glycol and 21 parts of diethylene glycol were charged into the same reactor as in Production Example 1 together with 0.1 part of zinc acetate as a catalyst. The temperature was raised to 190 to 220 ° C., and the reaction was carried out for 13 hours while removing water to obtain a polyester glycol having a molecular weight of 800 and a hydroxyl value of 140 KOHmg / g.
100 parts of the obtained polyester glycol, 100 parts of xylene and 28 parts of pyromellitic anhydride were charged into a reactor similar to the above and reacted at 140 ° C. for 1 hour, and then xylene was distilled off to 180 ° C. over 2 hours. The mixture was further kept at the same temperature for 1 hour. As a result, a carboxyl group-containing polyester resin (A-3) having a molecular weight of 18,000 and an acid value of 110 KOHmg / g was obtained.
[0034]
[Example 1] Example of binder for nonwoven fabric Polyester resin (A-1) was dissolved in water containing ammonia water equivalent to its acid value to prepare a 15% aqueous solution.
To 80 parts of this polyester resin aqueous solution, 0.2 parts of azobisisobutyronitrile, 5 parts of styrene and 3 parts of glycidyl methacrylate were added as a polymerization initiator and purged with nitrogen, followed by polymerization at 70 to 80 ° C. for 3 hours to form a solid. A modified polyester resin aqueous solution having a partial concentration of 23 wt% was obtained.
[0035]
Next, 3 parts of Denacol EX-313 (epoxy compound manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent 141) is mixed with 100 parts of this modified polyester resin aqueous solution. Was subjected to heat treatment for 10 minutes to produce a nonwoven fabric for ceramic polishing.
Using this polishing cloth, a ceramic polishing test was carried out in water at 50 ° C. for 100 hours. Even after 100 hours had elapsed, the nonwoven fabric was not deformed and the resin was not dropped, and good performance was exhibited.
[0036]
[Example 2] Example of heat-resistant water-clear paint A polyester resin (A-2) was dissolved in water containing 5% of ammonia water and butyl cellosolve equivalent to its acid value to prepare a 10% aqueous solution.
In 90 parts of this polyester resin aqueous solution, 0.1 part of ammonium persulfate was dissolved as a polymerization initiator, 8 parts of methyl methacrylate and 2 parts of glycidyl methacrylate were added and purged with nitrogen, followed by polymerization at 70 to 80 ° C. for 3 hours. Then, a modified polyester resin aqueous solution having a solid content concentration of 20 wt% was obtained.
[0037]
Next, 1 part of Denacol EX-313 was mixed with 100 parts of this modified polyester resin aqueous solution, then applied to a stainless steel plate so that the resin thickness was 20 μm, dried at 100 ° C. for 5 minutes, and then heat treated at 180 ° C. for 2 minutes. It was. The adhesion of the coating film by the cross-cut tape method (JISK5400 8.5.2) is good. Furthermore, when this processed plate is immersed in boiling water, no abnormalities such as whitening are observed after 10 hours, and good hot water resistance showed that.
[0038]
[Example 3] Example of antifogging agent for polyester film A polyester resin (A-2) was dissolved in water containing 5% of ammonia water and butyl cellosolve equivalent to the acid value to prepare a 10% aqueous solution.
In 90 parts of this polyester resin aqueous solution, 0.1 part of 2,2'-azobis- (amidinopropane) dihydrochloride as a polymerization initiator is dissolved, and further 8 parts of 2-hydroxyethyl methacrylate and 2 parts of glycidyl methacrylate are added. After purging with nitrogen, a polymerization reaction was performed at 70 to 80 ° C. for 3 hours to obtain a modified polyester resin aqueous solution having a solid content concentration of 20 wt%.
[0039]
Next, 5 parts of Denacol EX-1101 (Negase Kasei Kogyo Epoxy Emulsion, Epoxy Equivalent 520) was mixed with 100 parts of this polyester resin aqueous solution, and then applied to a 100 .mu. Polyester film so that the resin thickness was 3 .mu.m. After drying at 1 ° C. for 1 minute, heat treatment was performed at 180 ° C. for 1 minute. Adhesion test and antifogging property of the coated surface of the obtained film by the cross-cut tape method are good, and this processed film was immersed in hot water at 80 ° C. for 3 hours, but no abnormality such as whitening was observed. It was.
[0040]
[Example 4] Example of heat-resistant water clear paint Polyester resin (A-3) was dissolved in water containing N, N-dimethylethanolamine equivalent to its acid value to prepare a 15% aqueous solution.
In 80 parts of this polyester resin aqueous solution, 0.1 part of ammonium persulfate as a polymerization initiator was dissolved, and further 5 parts of butyl methacrylate and 3 parts of glycidyl methacrylate were added and purged with nitrogen, and then at 70 to 80 ° C. for 3.5 hours. A polymerization reaction was performed to obtain a modified polyester resin aqueous solution having a solid content concentration of 23 wt%.
[0041]
Next, 3 parts of Denacol EX-313 was mixed with 100 parts of this modified polyester resin aqueous solution, and then processed into a stainless steel plate in the same manner as in Example 2. The adhesion of the obtained processed plate by the cross-cut tape method was good, and when the processed plate was immersed in boiling water for 10 hours, good hot water resistance was shown.
[0042]
[Comparative Example 1] Example of using unmodified polyester resin aqueous solution After preparing a 10% aqueous solution of polyester resin (A-2) in the same manner as in Example 2, Denacol EX-313 was added to 100 parts of this aqueous solution. 0.9 parts were mixed to prepare a 20 μm coating film on the stainless steel plate in the same manner as in Example 1. The adhesion of the coating film by the cross-cut tape method was good, but when immersed in boiling water for 1 hour, the coating film was whitened.
[0043]
[Comparative Example 2] When no epoxy crosslinking agent was used A stainless steel plate was processed in the same manner as in Example 2 except that only the modified polyester resin was used without mixing the epoxy crosslinking agent in Example 2. Although the adhesion of the coating film by the cross-cut tape method was good, when immersed in boiling water, no abnormality was observed after 1 hour, but whitening of the coating film was observed after 3 hours.
[0044]
[Comparative Example 3] When Y / X is 5 or more In Example 3, 100 μm of polyester film was exactly the same as Example 3 except that 25 parts of Denacol EX-1101 was mixed with 100 parts of the modified polyester resin aqueous solution. It was processed into. When the adhesiveness of the coated surface was tested by a cross-cut tape method, peeling of the processing agent was observed.
[0045]
When the glycidyl group-containing vinyl monomer is 10% by weight or less Stainless steel is the same as in Example 2 except that 10 parts of methyl methacrylate is used as a radical polymerizable vinyl monomer in the polymerization reaction of the modified polyester resin aqueous solution in Example 2. Processed into a plate. The adhesion of the coating film by the cross-cut tape method was good, but when immersed in boiling water, no abnormality was observed after 1 hour, but whitening of the coating film was observed after 4 hours.
[0046]
【effect】
As described in the detailed description, the resin composition of the present invention is hydrophilic, water-soluble or water-dispersible and easy to handle, and the film obtained by drying or heat treatment is tough and has hot water resistance. It has an excellent property that it does not cause softening, embrittlement, peeling or whitening even when placed in hot water for a long time.
[0047]
Therefore, it is useful for applications such as paints and printing inks, plastics such as polyester and polypropylene, coating agents such as metal and paper, and binders for fibers.
Further, when a hydrophilic radically polymerizable monomer is used in combination, it is also effective for applications such as an antifogging agent and a hydrophilic processing agent.
[0048]
It can also be used in combination with UV curable resins, electron beam curable resins, and other aqueous resins. If necessary, pigments, film-forming aids, thickeners, leveling agents, anti-blocking agents, UV absorbers, antioxidants Such additives may be blended.

Claims (4)

In an aqueous solution or aqueous dispersion of a polyester resin having a molecular weight of 2,000 to 30,000 and containing a carboxylate, 20 to 100% by weight of a radically polymerizable vinyl monomer containing glycidyl group and another radically polymerizable vinyl monomer 80 The modified polyester resin (A) obtained by polymerizing ˜0% by weight and the epoxy group-containing cross-linking agent (B) having two or more epoxy groups in one molecule have a compounding ratio of Y / X = 0. A heat resistant water film forming resin composition formulated so as to have 2 to 5.
However, X: the equivalent of the carboxyl group of the modified polyester resin (A) Y: the equivalent of the epoxy group of the epoxy group-containing crosslinking agent (B) 2. The heat resistant water film forming resin composition according to claim 1, wherein the carboxylate is a carboxylate-containing polyester resin of an alkali metal salt, an ammonium salt or an amine salt. The heat resistant water film forming resin composition according to claim 1 or 2, wherein a carboxylate-containing polyester resin having an acid value of 15 to 250 KOHmg / g is used. The heat-resistant water-soluble film-forming resin composition according to any one of claims 1 to 3, wherein a ratio of the carboxylate-containing polyester resin and the radical polymerizable vinyl monomer is 95: 5 to 20:80 in terms of solid content weight ratio.