JPH0482022B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a solvent-free aqueous binder. In general, coating films formed from water-soluble paints containing a water-soluble alkyd resin as a vehicle component generally have excellent density, but have poor drying properties; Coating films formed from emulsion paints containing as a vehicle component have excellent drying properties, contrary to the properties of coating films formed from water-soluble paints, but have the disadvantage of poor density. As a representative example of improving the shortcomings of both of them, JP-A-53-
A mixture of a water-soluble resin and a polymerized emulsion using a maleated alkyd resin as a dispersion stabilizer, as disclosed in Japanese Patent No. 7734, has been proposed. However, this method requires a large amount of organic solvent to help dissolve or disperse the water-soluble resin and maleated alkyd resin in water, and the solvent deteriorates the storage stability of the paint and also causes pollution and fire. It has the disadvantage of being dangerous and having a negative effect on the drying properties of the coating film. The present invention aims to provide the production of a solvent-free water-based binder that is non-polluting, poses no risk of fire, has excellent storage stability and drying properties, and is particularly suitable for forming protective coatings on metal surfaces. be. As a result of intensive research to develop a method for producing a solvent-free aqueous binder that does not have these conventional drawbacks, the present inventors have discovered a polymeric type using a maleated alkyd resin and a maleated alkyd resin as a dispersion stabilizer. Using a binder component mixed with an emulsion in a specific ratio, and adding a specific alcohol dispersion aid to the component, the binder component is dispersed in water.
This is a method for obtaining a solvent-free aqueous binder by further removing the dispersion aid. That is, in the present invention, a neutralized product of a maleated alkyd resin () having an acid value of 10 to 60 and an oil length of 30 to 70 has a carbon number of 2.
Or an emulsion (A) obtained by dispersing in water using three alcohol dispersion aids (hereinafter referred to as "dispersion aids") and maleation with an acid value of 30 to 100 and an oil length of 30 to 70. An emulsion (B) obtained by dispersing the neutralized product of the alkyd resin () in water using the above-mentioned dispersion aid and emulsion polymerization of a radically polymerizable monomer in the presence of the neutralized product, and then (A) component is prepared. and (B) component in terms of solid content weight ratio of 5 to 90% of the former.
A method for producing a solvent-free aqueous binder, characterized in that the dispersion aid is removed before or after the mixing at a ratio of 95 to 10% of the latter. The emulsion (A) used in the present invention is prepared by dissolving the maleated alkyd resin () in a dispersion aid before or after neutralization with a neutralizing agent. This is carried out by adding water to the product after neutralization, or by dispersing the product in water. More preferably, this is carried out by adding water to a solution of the neutralized product of the maleated alkyd resin () to cause phase inversion. The maleated alkyd resin () mainly contains (semi-)drying oil and/or its fatty acids, polybasic acids,
It is obtained by reacting a monobasic acid and a polyhydric alcohol, and further by reacting maleic anhydride. The (semi-)drying oils and/or their fatty acids used include, for example, linseed oil, safflower oil,
Soybean oil, sesame oil, poppy seed oil, eno oil, hempseed oil, grape kernel oil, corn oil, sunflower oil, cottonseed oil,
Examples include walnut oil, rubber seed oil, tung oil, ostica oil, dehydrated castor oil, and fatty acids thereof, tall oil fatty acids, high diene fatty acids, and the like. Among them, it is preferable to use linseed oil, which is easily maleated and has good water dispersibility. The blending amount of the (semi-)drying oil and/or its fatty acid is about 30 to about 70% by weight based on the solid content of the maleated alkyd resin ().
It is. When the blending amount is less than 30% by weight, the maleation reaction becomes difficult, the storage stability of the emulsion is poor, and the drying properties of the coating film formed thereby are poor. On the other hand, if it is more than 70% by weight, there is a drawback that the coating film performance is poor. The polybasic acid is a compound having 2 to 4 carboxyl groups in one molecule. in particular,
For example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrophthalic acid, succinic acid, maleic acid, adipic acid, sebacic acid,
azelaic acid, hymic acid, itaconic acid, methylcyclohexentricarboxylic acid, crotonic acid,
Pyromellitic acid and anhydrides thereof, etc. can be used. Among these, phthalic acid, isophthalic acid, and terephthalic acid are preferred. Examples of the monobasic acid include benzoic acid, paratertiary butylbenzoic acid, methylbenzoic acid, non-drying oil fatty acid, rosin, etc., which do not contain the above-mentioned fatty acids and are generally used in the production of alkyd resins. Among these, benzoic acid is preferred because it is low cost and has high coating film hardness. The polyhydric alcohol is an alcohol having 2 to 6 hydroxyl groups in one molecule, and specifically includes, for example, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butanediol, decanediol, diethylene glycol, and pentanediol. ,
Neopentyl glycol, glycerin, diglycerin, triglycerin, trimethylolethane,
trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol,
Examples include 1.4 cyclohexanedimethanol, tricyclodecane dimethanol, trisisocyanurate, and the like. Further, as alcohols other than those mentioned above, dimethylolpropionic acid, lactone, epoxy resin, styrene-allyl alcohol copolymer, etc. can also be used. The maleated alkyd resin () is produced by subjecting the above-mentioned components to a dehydration condensation reaction at about 150 to 250°C for about 5 to 15 hours in an inert gas atmosphere according to a known synthesis method. A mixture of resin and maleic anhydride is heated at about 150 to 220℃ for about 1 to 6 hours.
This is done by a time reaction. The acid value of the maleated alkyd resin thus obtained is 10.
~60, preferably 15-45. If the acid value is less than 10, water dispersion becomes difficult, whereas if it is greater than 60, it becomes water-soluble and the storage stability, water resistance of the coating film, etc. are impaired. Further, the oil length of the maleated alkyd resin () is in the range of 30 to 70, preferably in the range of 20 to 60, more preferably in the range of 30 to 55. When the oil length is less than 30, the amount of maleic anhydride added becomes small and a stable maleated alkyd resin emulsion cannot be obtained. On the other hand, if it is more than 70, the water resistance of the coating film will be impaired. The viscosity of the maleated alkyd resin () used in the present invention is, but is not limited to, a Gardner foam viscometer value in the range of K to _Z5 in a 60% by weight diluted butyl cellosolve solution. When the Gardner foam viscometer value is smaller than K, water dispersion becomes easy, but the stability of the emulsion deteriorates and it is difficult to maintain a balance between the two. Moreover, the water resistance of the coating film is also poor. On the other hand, if the value is larger than _Z5 , water dispersion becomes difficult and the amount of organic solvent required for water dispersion increases, which is not preferable. The dispersion aid is an alcohol having 2 or 3 carbon atoms, specifically ethyl alcohol, n-propyl alcohol, and isopropyl alcohol. Two or more kinds of the dispersion aids can be used in combination. If the number of carbon atoms in the alcohol component is less than 2, the effect of dispersing the maleated alkyd resin in water is small, and if the number of carbon atoms is more than 3, it is difficult to remove, and the storage stability of the emulsion is lowered, which is not preferable. . The blending amount of the dispersion aid is in the range of about 5 to 100% by weight, preferably in the range of about 10 to 60% by weight, based on the solid content of the maleated alkyd resin (). If the amount of the solvent is less than about 5% by weight, it will have little effect on water dispersion, and if it is more than about 100% by weight, the solubility in water will improve, making water dispersion worse. Manufacturing costs also increase. The neutralizing agent is ammonia and organic amine for water dispersing the maleated alkyd resin (2), for example, a primary, secondary or tertiary neutralizing agent.
Typical examples include methylamine, ethylamine, propylamine, butylamine, amylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, trimethylamine, triethylamine, tripropylamine, morpholine; primary, Secondary or tertiary alkanolamines, typical examples include monoethanolamine, diethanolamine, dimethylethanolamine, diethylethanolamine, and the like. Among these neutralizing agents, diethylamine, triethylamine, and dimethylethanolamine are preferred because they have good dispersibility and are highly volatile and do not easily remain in the coating film. Further, the above neutralizing agents can be used alone or in combination of two or more. The amount of neutralizing agent used is generally 0.1 to 2.0 equivalents, preferably 0.3 to 1.0 equivalents, based on the carboxyl groups in the resin. Next, the preparation of emulsion (B) used in the present invention is as follows:
Before or after neutralizing the maleated alkyd resin () with the neutralizing agent, the same amount of the dispersing aid as above is used to dissolve it. If neutralization has not been carried out, after neutralization, the radically polymerizable monomer is heated to about 40 to about 100°C using the neutralized product of the maleated alkyd resin () as a dispersion stabilizer.
This can be carried out by emulsion polymerization at a reaction temperature of about 5 minutes to about 10 hours. The maleated alkyd resin (2) can be obtained using the same raw materials as those used for the maleated alkyd resin (2). The acid value of the maleated alkyd resin () needs to be in the range of 30 to 100, preferably in the range of 40 to 80. If the acid value is less than 30, lumps of vinyl polymer will occur during emulsion polymerization, and conversely, if the acid value is more than 100, storage stability and water resistance of the coating film will be poor. Further, the oil length of the maleated alkyd resin () is in the range of 30 to 70, preferably 20 to 70.
It is in the range of 60. If the oil length is less than 30, the amount of maleic anhydride added will be small and a stable emulsion will not be obtained, while if it is greater than 70, the water resistance of the coating film will be impaired. The radically polymerizable monomer can be used without particular limitation as long as it is used in general emulsion polymerization. Such radically polymerizable monomers include, for example, the general formula CH ₂ =C(R ₁ )COOR ₂
(However, in the formula, R ₁ represents hydrogen or a methyl group, and R ₂ represents an alkyl group having 1 to 12 carbon atoms.) (Meth)acrylic acid esters; (poly)ethylene glycol diacrylate, (poly)propylene Polyfunctional acrylic monomers such as glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate;
Vinyl aromatic monomers such as styrene, α-methylstyrene, vinyltoluene, and P-chlorostyrene; polyolefin monomers such as butadiene, isoprene, and chloroprene; vinylpyridine, vinylpyrrolidone, (meth)acrylamide,
Examples include nitrogen-containing acrylic monomers such as N-butoxymethylacrylamide, (meth)acrylonitrile, vinyl acetate, Beoba monomer (Siel Chemicals), vinyl propionate, vinyl bivalate, and the like. These monomers may be used alone or in combination of two or more. Further, hydrophilic monomers such as α,β-ethylenically unsaturated carboxylic acid and hydroxyalkyl acrylate can also be used in combination with the above monomers. The blending amount of the monomer is generally in the range of 5 to 80% by weight, preferably 10 to 75% by weight of the maleated alkyd resin () relative to 95 to 20% by weight, preferably 90 to 25% by weight of the monomer. The solvent-free aqueous binder used in the present invention is prepared by distilling the emulsion (A) and emulsion (B) under reduced pressure at a temperature of about 100°C or lower, preferably about 70°C or lower, to remove the dispersion aid. Emulsion (A) and emulsion obtained by removing the resin solid content to about 5% by weight or less, preferably about 3% by weight or less, more preferably about 1% by weight or less
It can be carried out by mixing emulsion (B) or by pre-mixing emulsion (A) and emulsion (B) and then removing the dispersion aid to the same content as above under the above conditions. The blending ratio of the emulsion (A) and emulsion (B) is 5 to 90% by weight (solid content) of the emulsion (A).
The emulsion (B) is in the range of 95 to 10% by weight, preferably the emulsion (B) is in the range of 90 to 20% by weight relative to the emulsion (A) in the range of 10 to 80% by weight (solid content).
If the amount of emulsion (A) is less than 5% by weight, it will affect the density of the coating film that is formed, resulting in poor water resistance and other properties.
If the amount is more than 90% by weight, the drying properties of the coating film will be poor. The solid content concentration of the solvent-free aqueous binder thus obtained is not particularly limited, but is generally about 15 to about 65% by weight. In addition, it is also possible to add conventionally known coloring pigments, extender pigments, pigment dispersants, antifoaming agents, plasticizers, dryers, antifreeze agents, etc. to the solvent-free aqueous binder, if necessary. . Next, the present invention will be further explained by manufacturing examples and examples. In the examples, parts and % indicate parts by weight and % by weight. Production Example of Maleated Alkyd Resin A mixture of 516 parts of isophthalic acid, 588 parts of pentaerythritol, 1647 parts of linseed oil fatty acid, and 548 parts of benzoic acid was placed in the reaction vessel of Example 5, and 0.5 part of monobutyltin oxide was esterified with respect to 100 parts of the mixture. A catalyst was added and a dehydration condensation reaction was carried out at 240° C. for 6 hours with stirring under a nitrogen atmosphere to obtain an alkyd resin with an acid value of 4.8. Next, 133 parts of maleic anhydride was added to the alkyd resin and a maleation reaction was carried out at 200°C for 3 hours to obtain an acid value of 45 and a Gardner foam viscosity (60% butyl cellosolve solution, hereinafter the same meaning).
A maleated alkyd resin (1) with X ⁺ and an oil length of about 55 was obtained. Similarly, maleated resins were produced using the formulations shown in Table 1 below to obtain maleated alkyd resins (2), (3) and (4). Production Example of Emulsion (A) 420 parts of the maleated alkyd resin (1) obtained above, 126 parts of isopropyl alcohol, and 34 parts of triethylamine were added to the container of 2, and stirred at a liquid temperature of 40°C. I got Japanese food. The neutralized product was then treated with deionized water at the same temperature as above.
After dispersion in water was carried out by dropping a portion over a period of about 1 hour, isopropyl alcohol was removed from the water dispersion under reduced pressure to obtain an emulsion (A). Production example of emulsion (B) (B-1) 140 parts of the maleated alkyd resin (2) obtained above, 35 parts of isopropyl alcohol, and 17 parts of triethylamine were added to the container of 2 while stirring at a liquid temperature of 40°C. 752 parts of deionized water was added to obtain a water dispersion. Then add 4.8 to the water dispersion.
After adding 23 parts of % ammonium persulfate aqueous solution, a mixture of 132 parts of styrene, 245 parts of N-butyl methacrylate and 42 parts of 1,6-hexanediol diacrylate was added to the reaction vessel and stirred for 30 minutes to mix uniformly. Ta. The reaction was carried out at 80° C. for about 2 hours with stirring. After the reaction was completed, the isopropyl alcohol was removed by distillation under reduced pressure at a liquid temperature of 40°C to obtain an emulsion (B-1). (B-2) Emulsion (B-1) except that 377 parts of N-butyl methacrylate was used instead of 132 parts of styrene and 245 parts of N-butyl methacrylate in the production example of emulsion (B-1).
Emulsion (B-2) was prepared in the same manner as in 1).
I got it. (B-3) Emulsion (B-1) except that 101 parts of styrene, 101 parts of methyl methacrylate, and 175 parts of 2-ethylhexyl acrylate were used instead of 132 parts of styrene and 245 parts of N-butyl methacrylate in the production example of emulsion (B-1). Emulsion (B-1) was produced in the same manner as in the production of emulsion (B-1).
-3) was obtained. Example 1 The emulsion of Example 1 was obtained by mixing 50 parts (solid content) of the emulsion (A) described above and 50 parts (solid content) of the emulsion (B-1) described above. Example 2 The emulsion of Example 2 was obtained by mixing 50 parts (solid content) of the emulsion (A) described above and 50 parts (solid content) of the emulsion (B-2) described above. Example 3 The emulsion of Example 3 was obtained by mixing 50 parts (solid content) of the emulsion (A) described above and 50 parts (solid content) of the emulsion (B-3) described above. Example 4 After mixing 50 parts (solid content) of the emulsion from which isopropyl alcohol has not been removed in the emulsion (A) and 50 parts (solid content) from which the isopropyl alcohol has not been removed from the emulsion (B), The emulsion of Example 4 was obtained by distilling under reduced pressure at a liquid temperature of 40°C to 50°C to remove isopropyl alcohol. Comparative Example 1 After adding 420 parts of the above maleated alkyd resin (3), 126 parts of butyl cellosolve and 34 parts of triethylamine, about 1 part of 684 parts of deionized water was added to the neutralized product.
Emulsion (a) was obtained by performing the dropwise addition over a period of time. Next, the maleated alkyd resin (4) 140 mentioned above
part, butyl cellosolve 49 parts and triethylamine
After adding 752 parts of deionized water while stirring at a liquid temperature of 40°C, emulsion polymerization was carried out in the same manner as in the production example of emulsion (B) to obtain emulsion (b) containing butyl cellosolve. Ta. An emulsion of Comparative Example 1 was obtained by mixing 50 parts (solid content) of the emulsion (a) and 50 parts (solid content) of the emulsion. Comparative Example 2 50 parts (solid content) of the emulsion (A) described above and 50 parts (solid content) of the emulsion (b) used in Comparative Example 1 were mixed to obtain an emulsion of Comparative Example 2. The properties and storage stability test results of the emulsion are shown in Tables 2 and 3. Comparative Example 3 After neutralizing by adding 420 parts of the maleated alkyd resin (1), 126 parts of methyl alcohol, and 34 parts of triethylamine, deionized water was added, but water dispersion was not possible.

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Claims (1)

[Claims] 1. A neutralized product of a maleated alkyd resin () having an acid value of 10 to 60 and an oil length of 30 to 70 is dispersed in water using an alcohol dispersion aid having 2 or 3 carbon atoms. Emulsion (A) with acid value 30~100 and oil length 30~
An emulsion (B) obtained by dispersing the neutralized maleated alkyd resin () of No. 70 in water using the dispersion aid and emulsion polymerizing a radically polymerizable monomer in the presence of the neutralized product, and then When mixing components (A) and (B) at a solid content weight ratio of 5 to 90% for the former and 95 to 10% for the latter, the dispersion aid is removed before or after the mixing. A method for producing a solvent-free aqueous binder, characterized in that: 2. The method for producing a solvent-free aqueous binder according to claim 1, wherein the alcohol dispersion aid having 2 or 3 carbon atoms is at least one selected from ethyl alcohol, n-propyl alcohol, and isopropyl alcohol. .