JPS6223002B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water-dispersible resin that can be easily dispersed in water. Water-dispersible resins are preferable compared to solvent-based resins due to disadvantages such as environmental protection, work environment, and resource saving.
In recent years, they have come to be widely used in paints, coatings, etc., but it is currently difficult to say that they are comparable to solvent-based resins in various aspects of performance. In particular, in water-dispersible resins obtained by polymerizing monomers in the presence of emulsifiers, the molecular weight of the polymer is generally extremely large, resulting in poor wetting of the coated surface and coating defects such as pinholes. Therefore, in addition to insufficient corrosion resistance, when a low molecular weight emulsifier is used, the emulsifier remains in the film formed by the water-dispersible resin, resulting in poor water resistance and There are problems with weather resistance, etc. The present invention has been made in view of the above, and includes:
The purpose of the present invention is to provide a water-dispersible resin that has excellent storage stability, pigment miscibility, and painting workability, has a high drying rate, and has a dried film that has excellent water resistance, corrosion resistance, weather resistance, etc. That is, the gist of the present invention is that the general formula

[Formula] (In the formula, R ₁ is H or CH ₃ , R ₂ is

【formula】 【formula】

[Formula] There is Yeah

[Formula] and R ₃ is H or CH ₃ . ) 0.5 to 50% by weight of an ester of acrylic acid or methacrylic acid having a cyclic unsaturated compound and 5 to 50% by weight of an α,β-unsaturated carboxylic acid
A water-dispersible resin characterized in that a radically polymerizable monomer is polymerized in an organic solvent in the presence of a vinyl copolymer having as a constituent unit, and the resulting polymer is neutralized with a base. It depends on the manufacturing method. Specific examples of esters of acrylic acid or methacrylic acid having a cyclic unsaturated compound used in the present invention include 3(4)-acryloxy-1-cyclopentene (which includes 3-acryloxy-1-cyclopentene and 4-acryloxy-1 3(4)-methacryloxy-1-cyclopentene, 3(4)-acryloxy-2-methyl-1-cyclopentene, 4-acryloxy-3-methyl-1-cyclopentene,
3(4)-methacryloxy-2-methyl-1-cyclopentene, 4-methacryloxy-3-methyl-1
-Cyclopentene, 4(5)-acryloxy-1-cyclohexene, 4(5)-methacryloxy-1-cyclohexene, 4(5)-acryloxy-2-methyl-
1-cyclohexene, 4(5)-acryloxy-3-
Methyl-1-cyclohexene, 4(5)-methacryloxy-2-methyl-1-cyclohexene, 4(5)-
Methacryloxy-3-methyl-1-cyclohexene, 5(6)-acryloxybicyclo[2.2.1]-2
-Heptene, 5(6)-methacryloxybicyclo[2.2.1]-2-heptene, 5(6)acryloxybicyclo[2.2.1]-3-methyl-2-heptene, 5
(6) acryloxybicyclo[2.2.1]-4-methyl-2-heptene, 5(6) methacryloxybicyclo[2.2.1]-3-methyl-2-heptene, 5(6) methacryloxybicyclo[2.2] .1〕-4-methyl-2
-Heptene, 8(9) acryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene, 8(9)-methacryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene, 8(9)
―Acryloxytricyclo[5.2.1.0 ² , ⁶ ]―2―
Methyl-4-decene, 8(9)-acryloxytricyclo[5.2.1.0 ² , ⁶ ]-3-methyl-4-decene,
8(9)-methacryloxytricyclo [5.2.1.0 ² , ⁶ ]
-2-methyl-4-decene, 8(9)-methacryloquitricyclo[5.2.1.0 ² , ⁶ ]-3-methyl-4-decene, etc. In particular, air based on the double bond of the ester 8(9)-acryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene, 8(9)- in that it has excellent curability and can form a film with excellent water resistance.
Methacryloxytricyclo [5.2.1.0 ² , ⁶ ]-4-
Decene is preferred. The vinyl copolymer used in the present invention contains the above-mentioned ester in an amount of 0.5 to 50% by weight (hereinafter, % refers to % by weight). If it is less than 0.5%, the resulting water-dispersible resin will have poor air curability and will therefore only form a film with poor water resistance.On the other hand, if it is more than 50%, the film formed by the water-dispersible resin will be It is easily colored and has poor weather resistance. Further, the vinyl copolymer contains α,β-unsaturated carboxylic acid as a structural unit in the range of 5 to 50% so as to have hydrophilicity, and has an acid value of 30 to 350. When it is less than 5%, the stability of the water-dispersible resin obtained after polymerizing the radically polymerizable monomer in the presence of such a vinyl copolymer becomes poor, and when it is more than 50%, the stability of the water-dispersible resin becomes poor. The film formed by the plastic resin will have poor water resistance. As such α,β-unsaturated carboxylic acids, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, cinnamic acid, maleic acid, fumaric acid, etc. are preferably used. Vinyl copolymers have a weight average molecular weight of 500~
150,000, preferably in the range of 1,000 to 100,000. If the weight average molecular weight is less than 500, the water resistance of the film formed by the water-dispersible resin will not be sufficient, and if it is greater than 150,000, the viscosity will decrease when the radically polymerizable monomer is polymerized in the presence of this copolymer. This is because the amount is too high and the amount used is limited, resulting in the resulting water-dispersible resin not only lacking in stability but also poor in air curability. Furthermore, in the present invention, the vinyl copolymer contains, in addition to the above ester and α,β-unsaturated carboxylic acid,
0 other appropriate vinyl monomers as structural units
It may be contained in a range of 94.5%. A specific example of such a vinyl monomer is butyl (meth)
acrylate, (this means both butyl acrylate and butyl methacrylate, the same applies hereinafter), (meth)acrylic acid alkyl esters such as 2-ethylhexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, etc. ) acrylate etc. (meta)
Examples include hydroxyalkyl acrylate, styrene, α-methylstyrene, alkenylbenzenes such as vinyltoluene, and furthermore vinyl acetate and acrylonitrile. As mentioned above, a vinyl copolymer consisting of an ester of acrylic acid or methacrylic acid having a cyclic unsaturated compound, an α,β-unsaturated carboxylic acid, and other structural units as necessary has been generally known. It can be obtained by copolymerizing each monomer according to a method described in the following. In the present invention, a radically polymerizable monomer is polymerized in an organic solvent in the presence of such a vinyl copolymer by a conventional method (that is, the radically polymerizable monomer is polymerized by a solution polymerization method). This polymer consisting of the above-mentioned vinyl copolymer is neutralized with a base. The above-mentioned radically polymerizable monomers are not particularly limited, but specific examples include (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. In addition to acrylic acid alkyl esters and glycidyl (meth)acrylate, examples include alkenylbenzenes such as styrene, α-methylstyrene, and vinyltoluene, as well as vinyl acetate, vinylpyridine, butadiene, isoprene, chloroprene, acrylonitrile, and methacrylonitrile. . These may be used alone or as a mixture of two or more. If necessary, small amounts of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylamide, methacrylamide, dimethylaminoethyl methacrylate, N-methylol-acrylamide, N-butoxymethylacrylamide, Hydrophilic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and styrenesulfonic acid may also be used together. Polyfunctional polyacrylates such as ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpumpane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and diallyl phthalate. A crosslinking agent may also be used in combination. Furthermore, any solvent may be used for polymerizing the above-mentioned radically polymerizable monomer in the presence of the vinyl copolymer, as long as the polymerization reaction proceeds smoothly. and a solvent that dissolves these polymers is desirable. Specific examples of solvents include propanol,
One or a mixture of two or more water-soluble organic solvents such as methyl cellosolve, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, acetone, methyl ethyl ketone, and ethyl acetate are used, and may contain a small amount of water. In addition, radical polymerization initiators include benzoyl peroxide, t-butyl perbenzoate, di-
Any conventionally known materials can be used without particular limitation, such as t-butyl peroxide, cumene hydroperoxide, and azobisisobutyronitrile. The amount of the vinyl copolymer used is about 5 to 95% by weight, preferably about 5 to 80% by weight, based on the total amount of the copolymer and the radically polymerizable monomer. If the amount of vinyl copolymer used is too small, the water-dispersible resin obtained by neutralizing the polymer will lack stability, and
If it does not have sufficient air curing property or if it is too large,
This is because the film formed by the water-dispersible resin will lack water resistance. It is thought that the thus obtained polymer consisting of the vinyl copolymer is composed of most of the radically polymerizable monomer grafted onto the vinyl copolymer. The weight average molecular weight is preferably in the range of 2,000 to 150,000. If the weight average molecular weight is less than 2,000, the curing speed of the resulting water-dispersible resin will be slow and the resulting film will not have sufficient water resistance.On the other hand, if it is greater than 150,000, the viscosity will be too high and painting workability will be impaired. This is because there are disadvantages such as the need to reduce the resin concentration unnecessarily. The water-dispersible resin of the present invention can be obtained by neutralizing and diluting such a polymer comprising a vinyl copolymer with a base such as ammonia or amine and water. As the amine, triethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, morpholine, etc. can be used, but the present invention is not limited to these. Furthermore, the solvent may be removed if necessary. The method of the present invention is configured as described above, and the water-dispersible resin obtained by the present invention has excellent storage stability and mechanical stability due to the dispersion stability ability of the vinyl copolymer having the above-mentioned structural units. It not only has pigment miscibility, but also has high air curability due to the air curability of the vinyl copolymer, and the resulting coating has excellent water resistance. On the other hand, since the vinyl copolymer itself is water-soluble, the water-dispersible resin according to the present invention can be uniformly applied to the object to be coated, and the dried film has excellent water resistance as described above. At the same time, it has no coating defects such as pinholes and exhibits excellent corrosion resistance and weather resistance. In addition, when the water-dispersible resin obtained by the method of the present invention is used as a paint for room temperature or forced drying, a metal drying agent such as cobalt naphthenate or lead naphthenate may be used, and an amino resin,
Of course, it may be modified by mixing an epoxy resin or the like. The present invention will be explained below with reference to Examples. In the Examples below, the acid value and molecular weight of the polymer, the storage stability of the water-dispersible resin, and the various physical properties of the coating film obtained therefrom were evaluated as follows. (1) Acid value: The sample was diluted with toluene/ethanol (9/
1) Determined by dissolving in a mixture and performing neutralization titration with a 0.1N potassium hydroxide ethanol solution using phenolphthalein as an indicator. (2) Weight average molecular weight: Regarding the 5% tetrahydrofuran solution of the sample, GPC manufactured by Waters Co.
It was determined by gel vermi- ation chromatography using a Model 200 machine. (3) Storage stability of water-dispersible resin: After putting a water-dispersible resin with a solid content of 40% in a 100ml sample bottle and sealing it, it was left at a temperature of 50℃ for 7 days, and the viscosity change, phase separation, etc. We observed changes in (4) Physical properties of coating film: 100g of water-dispersible resin with a solid content of 40%
40g of titanium oxide and 0.1g of cobalt naphthenate.
was added and stirred at high speed to adjust the paint. This coating film was applied to a zinc-treated steel plate using air spray to a film thickness of 40μ, and after being left at room temperature for 20 minutes,
It was dried at ℃ for 20 minutes and then at room temperature for 5 days. 60% by specular gloss measuring device for this coating film.
The degree of specular gloss at 60°/60° was measured and used as a measure of pigment compatibility. In addition, the coating film was immersed in pure water at room temperature for 10 days, and abnormalities such as rust and blistering were observed. If no abnormalities were observed, the water resistance was determined to be good. In addition, the cut surface of the coating film was observed with a magnifying glass to check for the presence or absence of coating film defects, and a coating film condition with no coating film defects was considered to be good. Reference Example 1 100g of butyl cellosolve was charged into a separable flask equipped with a stirrer, a thermometer, a dropping funnel, a cooling tube, and a nitrogen introduction tube, the inside of the flask was replaced with nitrogen, the temperature was raised to 100℃, and azobisisomer was added. 8 or (9)-acryloxy-tricyclo[5.2.1.0 ² , ⁶ ]-4-decene in which 4 g of butyronitrile was dissolved.
72g, acrylic acid 31g, butyl methacrylate
97 g of dodecyl mercaptan and 2 g of dodecyl mercaptan were added dropwise over 2 hours, and the mixture was further stirred for 3 hours to carry out a copolymerization reaction to obtain a colorless and transparent butyl cellosolve solution of a vinyl copolymer with an acid value of 105 and a weight average molecular weight of 18,000. Reference Example 2 In the same manner as Reference Example 1, 8 or (9)-methacryloxy-tricyclo[5.2.1.0 ² , ⁶ ]-4-decene30
g, 30 g of methacrylic acid, 110 g of 2-ethylhexyl acrylate, 30 g of styrene, and 2 g of dodecyl mercaptan were added dropwise and stirred to perform a copolymerization reaction, resulting in a colorless and transparent butyl cellosolve solution of a copolymer with an acid value of 90 and a weight average molecular weight of 20,200. I got it. Example 1 80 g of butyl cellosolve was added to 61.2 g of the copolymer solution obtained in Reference Example 1 in a single-separable flask similar to that of Reference Example 1, and after purging with nitrogen and raising the temperature to 100°C, t-butyl per- 0.8 g of octoate was added and dissolved. Furthermore, butyl methacrylate
2 mixed solutions of 140g and 20g of butyl acrylate
The mixture was added dropwise into the flask over a period of time, and then stirred for 3 hours to carry out homogeneous polymerization to obtain a polymer solution.
Next, 60 g of this polymer solution was added to triethylamine.
By adding 0.5 g and 40 g of pure water and stirring at high speed, the mixture was neutralized and diluted to obtain a milky white water-dispersible resin. This water-dispersible resin has good storage stability,
The water resistance of the coating film was good, and the gloss was 81, indicating that the pigment miscibility was also good. Moreover, the condition of the coating film was good. Example 2 In the same manner as in Example 1, 80 g of butyl cellosolve was added to 61.2 g of the copolymer solution obtained in Reference Example 2, and 140 g of butyl methacrylate was added in the presence of the copolymer.
20 g of butyl acrylate were homogeneously polymerized to obtain a polymer solution. Furthermore, in the same manner as in Example 1, diethylaminoethanol was added to 60 g of the polymer solution.
A milky white water-dispersible resin was obtained by adding 0.5 g and 40 g of pure water and stirring at high speed. This water-dispersible resin has good storage stability,
The water resistance of the coating film was good, and the gloss was 88, indicating that the pigment compatibility was also good. Moreover, the condition of the coating film was good.

Claims (1)

[Claims] 1 General formula [Formula] (wherein R ₁ is H or CH ₃ , R ₂ is [Formula] [Formula] [Formula] or [Formula], and R ₃ is H or CH ₃ ) of a vinyl copolymer having as constituent units 0.5 to 50% by weight of ester of acrylic acid or methacrylic acid having a cyclic unsaturated compound and 5 to 50% by weight of α,β-unsaturated carboxylic acid. 1. A method for producing a water-dispersible resin, which comprises polymerizing a radically polymerizable monomer in an organic solvent in the presence of a base, and neutralizing the resulting polymer with a base. 2. Claim No. 2 in which the ester of acrylic acid is 8-acryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene or 9-acryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene The manufacturing method according to item 1. 3 The ester of methacrylic acid is 8-methacryloxytricyclo[5.2.1.0 ² , ⁶ ]-4-decene or 9
-Methacryloxytricyclo[5.2.1.0 ² , ⁶ ]-4
- The manufacturing method according to claim 1, wherein decene is used. 4. The production method according to any one of claims 1 to 3, wherein the vinyl copolymer further contains an α,β-unsaturated carboxylic acid alkyl ester or alkenylbenzene as a constituent unit. 5. The production method according to any one of claims 1 to 4, wherein the radically polymerizable monomer is an α,β-unsaturated carboxylic acid alkyl ester or alkenylbenzene.