JPS62949B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved composition of a vinyl polymer emulsion obtained by radical polymerization of an unsaturated vinyl monomer using a polymeric oxidation-curable water-soluble resin as an emulsion stabilizer. More specifically, the present invention relates to an improved aqueous coating composition capable of producing a hard and tough coating film by impregnating the emulsion with an allyl group-containing compound. The present inventors have conducted various studies on emulsions using a polymeric oxidation-curable water-soluble resin as an emulsion stabilizer. These emulsions have characteristics not found in ordinary emulsions due to oxidative curing, but when actually used as resins for low-pollution coatings, the minimum film forming temperature is sufficiently low. However, there was a drawback that it was not possible to achieve both sufficient hardness and coating film hardness. The present invention was completed as a result of intensive research to eliminate the above-mentioned drawbacks. That is, the present invention provides a maleated polydiene,
An emulsion obtained by radical polymerizing unsaturated vinyl monomers using at least one polymeric oxidation-curable water-soluble resin selected from maleated alkyds and maleated fatty acid-modified styrene-allyl alcohol copolymer resins as an emulsion stabilizer. , a reaction product of polyhydric alcohol and diallyl ether or a reaction product of aromatic dibasic acid and allyl alcohol, which has a relatively low molecular weight and excellent curability, with a molecular weight of 140 ~
After solubilizing 1500 allyl group-containing compounds with a fatty acid-modified water-soluble acrylic resin, by mixing 0.1 to 150 PHR with respect to the solid content of the emulsion, the minimum film formation temperature can be lowered and sufficient hardness can be achieved. It concerns the aqueous coating compositions that can be obtained. The vinyl polymer emulsion used in the present invention must be an emulsion containing a high molecular weight oxidation-curable water-soluble resin as an emulsifier. Emulsions that use such emulsifiers as dispersion stabilizers are produced because the emulsifier is a polymer, and a graft reaction occurs during emulsion polymerization, which further polymerizes and binds strongly to the emulsion surface.
It can withstand shock when impregnated with allyl group-containing compounds. Furthermore, during curing, since there is already a high-molecular oxidation-curable resin, the gel effect accelerates the curing of the allyl group-containing compound, and the gel network easily spreads throughout, creating a strong structure. A coating film is obtained. Examples of the polymeric oxidation-curable water-soluble resins that can be used in the present invention include maleated polydienes, maleated alkyds, maleated fatty acid-modified styrene-allylic alcohol copolymer resins, maleated fatty acid-modified water-soluble epoxy resins, maleated oils, The emulsion itself is easier to form when the structure of the part in contact with water is oily, such as maleated stand oil, maleated boiled oil, maleated fatty acid-modified acrylic resin, fatty acid-modified acrylic resin, etc.
It is also preferred because it is suitable for impregnating oil-based resins. Other usable water-soluble resins include water-soluble alkyd resins and oil-modified water-soluble epoxy resins. The number average molecular weight of these water-soluble resins is approximately 500
-50000, preferably about 800-15000, and the acid number is 20-350, preferably 50-200. The maleated polydiene has 4 to 8 carbon atoms.
Polymers of diene compounds and copolymers thereof are maleated by conventional methods. Maleated polybutadiene and copolymers thereof are preferred, and those containing 20% or more of 1,2-vinyl structure are particularly preferred because they are easy to graft during polymerization, stable, and have good weather resistance. In resins such as maleated alkyd resins, maleated fatty acid-modified epoxy resins, and maleated fatty acid-modified acrylic resins, the fatty acid groups are drying oil fatty acids or semi-drying oil fatty acids due to the necessity of maleation and oxidative curing. Therefore, the oil length must be 20 or more, preferably 40 or more. Among maleated oils, maleated stand oils, and maleated boiled oils, stand oils and boiled oils with high molecular weights are preferred. Fatty acid-modified water-soluble acrylic resin is made by copolymerizing acid monomers such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, hydrous acid group-containing monomers, or epoxy group-containing monomers, and other general monomers.
It is a resin that is finally in the form of a drying oil or a semi-drying fatty acid. In this case, in order to produce oxidative hardening and good emulsion, the oil length should be 5 or more, preferably
Must be 20 or higher. The above resins may be modified by epoxidation, esterification, amidation, grafting, etc. if necessary.
It may be modified with isocyanate, melamine, urea, etc. These resins are preferably neutralized with volatile amines, ammonia, etc. and, if necessary, made water-soluble with the aid of water-soluble organic solvents. An emulsion of a vinyl polymer can be obtained by radically polymerizing an unsaturated vinyl monomer in the above aqueous solution. The preferred unsaturated vinyl monomer used is one that is not strongly hydrophilic and generates a relatively inactive radical with a Q value of 0.1 or more in the Qe theory. If the hydrophilicity is too strong, emulsion synthesis becomes difficult and at the same time impregnation of allyl group-containing compounds is hindered. Furthermore, if the radical activity is too strong, it will react with the oxidative reactive groups of the water-soluble resin for dispersion stabilizer, causing the oxidative curing surface activity to be lost, and at the same time, polymerization will be inhibited. Examples of preferred monomers include styrene, α-methylstyrene, vinyltoluene, esters of alcohols having 1 to 26 carbon atoms with acrylic acid and methacrylic acid, and condensation of glycidyl acrylate and glycidyl methacrylate with carboxylic acids having 1 to 26 carbon atoms. methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, allyl acrylate, allyl methacrylate, butadiene, isoprene, chloroprene, etc.
These unsaturated vinyl monomers may be used alone or in combination of two or more. It can also be used in combination with the following monomers, but they must be contained in a total amount of 50% or more, preferably 70% or more. Monomers that can be used in combination with the above unsaturated vinyl monomers include 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate,
-Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid,
Glycidyl acrylate, glycidyl methacrylate, vinyl acetate, Beoba monomer (manufactured by Schiel Chemical Co., Ltd., trade name), Nn-butoxymethylacrylamide, acrylamide, vinylpyridine, and other general monomers capable of radical polymerization. Of course, it is also possible to use a mixture of two or more of these monomers. It is preferable that the Tg point of the entire monomer used is 60° C. or lower because this facilitates the penetration of the allyl group-containing compound. The amount of water-soluble resin used as a dispersion stabilizer is such that the acid value in the total solid content, including unsaturated vinyl monomers, is 3 to 3.
150, preferably 10 to 50. The allyl group-containing compound used for mixing with the vinyl polymer emulsion is preferably one that has a low molecular weight, is easily impregnated, and hardens quickly. For example, the following compounds can be used: That is, _CH2 =CH- _CH2 -O-,

【formula】

【formula】

【formula】

【formula】

Molecular weight 140-5000, in which one group, preferably two or more groups such as [Formula] are bonded,
Preferably it is a compound containing 200 to 3000 allyl groups. These compounds can be prepared by reacting polyhydric alcohols (e.g., trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, etc.) with diallyl ether or by reacting aromatic dibasic acids (e.g., phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, etc.) with diallyl ether. acid, etc.) and allyl alcohol. Since the allyl group-containing compound used in the present invention has an air-drying group that is smaller than a drying oil fatty acid group, it has the advantage of having a small overall molecular weight and the ability to synthesize a compound with a high activity concentration. This is advantageous for impregnating emulsions. The mixing ratio of the above low molecular weight oxidation-curable allyl group-containing compound is 0.1 to the solid content of the emulsion.
~150PHR. Preferably it is 3-50 PHR. The impregnation method can be carried out by stirring and mixing as is, but it is preferable to add after emulsifying or solubilizing with a water-soluble resin or a common emulsifier to avoid troubles such as the formation of lumps.
As the water-soluble resin, it is desirable to use an oxidation-curable water-soluble resin that is used as an emulsion stabilizer for the emulsion of the present invention. The emulsion according to the present invention has high quality as a resin for room-temperature curable coatings, but
Of course, heating and curing is also possible, and in that case,
You can also add melamine, etc. In addition, it can be widely used in resin processing agents, adhesives, etc. Next, the present invention will be explained in detail with reference to Examples, but the Examples are not intended to limit the present invention. Parts and percentages refer to parts and percentages by weight. Reference Example 1 Method for Producing Emulsion A 1,2-vinyl polybutadiene with a number average molecular weight of 3000 was maleated to obtain maleated polybutadiene with an acid value of 100. Neutralize this with 0.95 equivalents of ammonia, add 35 PHR of butyl cellosolve,
Dissolve in water, add 129 PHR of n-butyl methacrylate and 129 PHR of styrene and stir well to form an emulsion. In addition, for monomer
Add 0.25PHR ammonium peroxide,
Heat to 80℃ and keep for 2 hours. In this way, the solid content
A 40% fine emulsion A was obtained. Reference Example 2 Manufacturing method of emulsion B All hydroxyl groups of RJ-101 (styrene-allyl alcohol copolymer manufactured by Monsanto, number average molecular weight 1150) are added to linseed oil fatty acid (RJ-101/linseed oil fatty acid = approx. 16/20) was esterified and then maleated to obtain a resin with an oxidation rate of 100. Reference example 1
A product neutralized in the same manner as above was used in place of the maleated polybutadiene of Reference Example 1, and the monomers were i-butyl methacrylate of 259PHR and 1,6-hexanediol diacrylate corresponding to 2.4% of this. The mixture was used to obtain a fine emulsion B with a solids content of 40%. Reference Example 3 Production method of auxiliary water-soluble resin C that helps incorporation of oily compounds Safflower oil fatty acid-glycidyl methacrylate adduct 60 parts Styrene 27 parts Acrylic acid 13 parts The above monomers were polymerized dropwise into a butyl cellosolve solution, with a peak molecular weight of approximately 7000, A polymer with an acid value of 80 was obtained. As a dryer, 0.16 parts of Co (cobalt naphthenate), 0.16 parts of Mn (manganese naphthenate), and 0.45 parts of Pb (namali naphthenate) were added, and the auxiliary water-soluble resin C containing 25PHR butyl cellosolve was neutralized with ammonia. Obtained. Reference example 4 Manufacturing method of emulsion D 470 parts of isophthalic acid, 583 parts of pentaerythritol
A mixture of 599 parts of benzoic acid and 1644 parts of linseed oil fatty acid was heated to 240° C. in the presence of a dibutyltin oxide esterification catalyst, and the reaction was carried out for 6 hours until the resin acid value reached 1.3. Continue to adjust the temperature
The temperature was lowered to 200°C, 237 parts of maleic anhydride was added, and the maleation reaction was carried out at 200°C for 3 hours.
A resin with a resin acid Y of 62.6 Gardner viscosity (solid content 60% butyl cellosolve solution) was obtained. Next, 42 parts of isopropyl alcohol and 16 parts of triethylamine were added to 140 parts of the resin, dissolved in water, and 132 parts of styrene and 16 parts of triethylamine were added.
Add a mixture of 42 parts of 1.6-hexanediol diacrylate and stir well to form an emulsion. Add 23.2 parts of 4.7% ammonium persulfate aqueous solution to this and keep at 80°C for 2 hours. In this way, a fine emulsion D having a solid content of 40% was obtained. Example 1 Part of auxiliary water-soluble resin C (solid content, same below)
and 0.9 parts of trimethylolpropane diallyl ether are thoroughly mixed and then mixed into 9 parts of emulsion A. The performance test results of the obtained emulsion are shown in Table 1. Example 2 Instead of the allyl group-containing compound of Example 1, the same amount of diallyl phthalate was added. The performance test results of the obtained emulsion are shown in Table 1. Example 3 The same procedure as in Example 1 was carried out except that Emulsion B was used instead of Emulsion A in Example 1. Table 1 shows the performance test results of the emulsion. Example 4 The same procedure as in Example 2 was carried out except that Emulsion B was used instead of Emulsion A in Example 2. The performance test results of the emulsion are shown in Table 1. Example 5 Emulsion D was used in place of Emulsion A in Example 1. The performance test results are shown in Table-1. Comparative Example 1 In Example 1, no allyl group-containing compound was added. Comparative Example 2 In Example 3, no allyl group-containing compound was added. Comparative Example 3 In Example 5, no allyl group-containing compound was added. The minimum film formation temperature was 30°C or higher, which resulted in poor results with cracking and peeling of the dried paint film.

【table】

〔Test items〕

For the pencil hardness, use a Mitsubishi Uni Pencil with a hardness code of 6B to 9H.
The hardness symbols for the lower grades are shown in the table. The gel fraction was calculated from the weight before and after extraction with tetrahydrofuran. For adhesion, use a knife to cut out 1 x 1 mm squares.
When 100 pieces are cut and cellophane adhesive tape is applied to these parts and quickly peeled off, the adhesiveness is expressed as n/100, where n is the number of remaining goblets. Impact resistance was measured using a DuPont impact tester using a 500 g weight with a diameter of 0.5 inches (20°C). Erichsen values were measured using an Erichsen tester (20°C). Water resistance was determined by immersing the film in water at 20°C for one day and observing whether or not there were any abnormalities in the paint film. Corrosion resistance is based on JIS Z2371, and indicates the width of rust generated from the cut part after a one-day test. Storage stability was determined by examining changes in viscosity and pH after 14 days at 50°C. As for the viscosity change, a positive value indicates that the viscosity has increased, and a negative value indicates that the viscosity has decreased. Further, a negative PH value indicates a change to an acidic region.

Claims (1)

[Claims] 1 At least one polymeric oxidation-curable water-soluble resin selected from maleated polydienes, maleated alkyds, and maleated fatty acid-modified styrene-allyl alcohol copolymers as an emulsion stabilizer,
The emulsion obtained by radical polymerization of unsaturated vinyl monomers is modified with fatty acids with diallyl ether of polyhydric alcohol (molecular weight 140-1500) and/or diester of aromatic dibasic acid and allyl alcohol (molecular weight 140-1500). An aqueous coating composition that is solubilized with a water-soluble acrylic resin and then mixed with 0.1 to 150 PHR based on the solid content of the emulsion.