JPS6011757B2 - Aqueous coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous coating composition, and more particularly to an aqueous coating composition useful as a room-temperature curing overcoat composition and a rust-inhibiting composition.

Recently, water-based paints have been attracting attention as non-polluting paints, and there are two main types of water-based paints: those using water-soluble resins and those using emulsion-type resins. However, in paints using emulsion-type resins, the emulsion resin has a large molecular weight, and the particles do not "wet" the metal surface.
It cannot be said that its durability and corrosion resistance are sufficient due to its inferior properties and its characteristic of forming a porous coating film, which is unique to emulsions.

On the other hand, in conventional paints using water-soluble resins, many hydrophilic groups such as carboxyl groups are introduced into the resin in order to make it water-lacquer-like. However, due to its low molecular weight, it could not escape the drawbacks of poor water resistance and durability even when it became a dry coating film.

As a result of the present inventors' efforts to develop an aqueous coating composition that does not have these conventional defects, we have found that muscular oil fatty acid residues and/or semi-drying oil fatty acids connected to the main chain by ester bonds. Neutralized water-solubilized product (1) of a maleated or partially maleated product of an addition polymer having a residue as a side chain;
And an aqueous coating composition having as a vehicle main component an emulsion (b) obtained by emulsifying and bonding a radically polymerizable unsaturated single star with this neutralized aqueous solution (1) as a dispersion stabilizer. The present invention was completed by discovering that it has no defects and has excellent performance.

Conventionally, various attempts have been made to obtain oxidatively polymerizable emulsions using high molecular weight resins that have oxidatively polymerizable properties as dispersion stabilizers. It is used as a dispersion stabilizer. However, each of these has the following drawbacks. That is, maleated polybutadiene has too many double bonds, so it easily deteriorates when used in a place exposed to a large amount of external radiation, and maleated oil and maleated alkyd resin emulsify and bond. It has poor compatibility with unsaturated monomers, and furthermore, the carboxyl groups of maleated polybutadiene are not coordinated in the structure used to make emulsions, and during emulsion polymerization, polymerization chains with radically polymerizable unsaturated monomers occur. Because the drying oil fatty acids and semi-solid oil fatty acids, which have mobile unsaturated bonds, are mixed together, the formation of an emulsion does not proceed smoothly, and it is difficult to form an emulsion with a suitable particle size and sufficient oxidative polymerizability. Furthermore, attempts have been made to use neutralized products of fatty acid-modified acrylic resins copolymerized with acrylic acid or methacrylic acid with improved compatibility as dispersion stabilizers. However, the latter drawback has not been improved and a good emulsion has not been obtained.However,
The neutralized water residue (1) in the present invention has a high molecular weight and a structure suitable for use as a dispersion stabilizer for emulsion polymerization of radically polymerizable unsaturated monomers as shown below.

That is, the neutralized water-solubilized product (1) of the present invention is an addition polymerized polymer in the main chain, the side chain is a (partially) maleated drying oil or semi-drying oil fatty acid residue, and the main chain and the side chain are , are connected by an ester bond between a hydroxyl group or an epoxy group (glycidyl group) from the main chain and a carboxyl group from the side. The primary mirror is lipophilic and the side chains are hydrophilic. When a radically polymerizable unsaturated monomer is added to this neutralized water-solubilized product (1), this unsaturated monomer becomes a polymer ( It is well compatible with the part A), is not compatible with the water-soluble carboxylic acid part, and is relatively far away from the chain transfer unsaturated bond in the fatty acid part and the polymer (A). During emulsion polymerization, the unsaturated bonds of the radically polymerizable unsaturated monomer and the chain transfer type unsaturated bonds (unsaturated bonds in drying oil fatty acids and semi-drying oil fatty acids) are successfully separated, resulting in a good emulsion.

In other words, the radically polymerizable unsaturated monomer is located inside the emulsion particles, and the drying fat or semi-drying fat or fat part is located in the outer shell of the emulsion particle. The lotus chain transfer type double bonds contained in fatty acids or semi-hostile oil fatty acids rarely inhibit emulsion polymerization, and on the other hand, the active sites for oxidative hardening in the outer shell are less likely to be destroyed by radical polymerization. .
Furthermore, unlike when using maleated polybutadiene, the absolute number of double bonds is small (however, the activity is strong).
Weather resistance is good. Another feature is that the inside of the emulsion has a moderately low molecular weight, so it is easy to work with, and crosslinking after film formation is quick, so the physical properties and durability of the paint film are good. There are, for example, the following two methods for synthesizing the neutralized aqueous solution (1) used in the present invention.

One is allyl alcohol, 2-hydroxymethyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, glycidyl methacrylate containing hydroxyl or glycidyl groups such as glycidyl acrylate, Metallic-P [manufactured by NOF Chemical Co., Ltd.] An unsaturated monomer is copolymerized with a copolymerizable unsaturated monomer (A) to obtain a polymer (A), and a drying oil fatty acid or a semi-drying oil fatty acid is added thereto by esterification, followed by maleation and neutralization to make it water-solubilized. This is a method of doing this.

In particular, the polymer (A) obtained by using furyl alcohol as an unsaturated monomer containing a hydroxyl group or a glycidyl group is OH
It is suitable for producing a polymer having a high oil content and a long oil length, and also proceeds smoothly in emulsion polymerization, making it most suitable for obtaining the composition of the present invention. Another method is to produce a copolymer of an unsaturated monomer obtained by linking the epoxy ring of a glycidyl group-containing unsaturated monomer with a drying oil fatty acid and semi-drying oil fatty acid and a polymerizable unsaturated monomer (A). This is a method of maleating and neutralizing to make it water-soluble.
As the glycidyl group-containing unsaturated monomer, glycidyl acrylate, glycidyl methacrylate, etc. can be used. As the copolymerizable unsaturated monomer (A), styrene,
Vinyl toluene, Q-methylstyrene, acrylonitrile, methacrylonitrile, esterified products of monoalcohols having 1 to 26 carbon atoms and acrylic acid or methacrylic acid, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, etc. and monoalcohols having 1 to 8 carbon atoms, etc. Esterification of acrylic acid or methacrylic acid to monoetherified products with monoalcohols, adducts of glycidyl acrylate or glycidyl methacrylate and monocarboxylic acids other than drying oil fatty acids and semi-drying oil fatty acids having 4 to 26 carbon atoms, etc. One type or a mixture of two or more types can be used. In addition, monomers commonly used in radical polymerization such as butadiene, isoprene, chloroprene, bentadiene, vinyl acetate, vinyl chloride, and beoba monomer can also be used as the copolymerizable unsaturated monomer A.

The dry fatty acid and semi-dry fatty acid used in the present invention include, for example, safflower oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, hempseed oil fatty acid, poppy oil fatty acid, sunflower oil fatty acid, walnut oil fatty acid, etc. It contains many non-conjugated double bonds and can perform maleation and polymerization reactions without gelation.

Particularly preferred are those with good hardening properties, such as corn oil fatty acids, cottonseed oil fatty acids, mustard oil fatty acids, oticica oil fatty acids, fall seed oil fatty acids, enoic oil fatty acids, poppy seed oil fatty acids, rubber seed oil fatty acids, sesame oil fatty acids, and tolls. Oil fatty acids, tung oil fatty acids, dehydrated castor oil fatty acids, /. The amount of the drying oil fatty acid and/or semi-drying oil fatty acid may be 10 to 90 in terms of fatty acid oil length, and 35 to 85 is particularly preferable. Maleation of the drying oil fatty acid and semi-drying oil fatty acid residue part The reaction is 120
It is carried out by a conventional method at q○ to 250 qo. If there are many hydroxyl groups remaining in the addition-polymerized polymer containing fatty acid residues to be maleated, remove a large amount of hydroxyl groups by esterifying with a low-molecular or high-molecular acid, such as acetic acid, propionic acid, or stearic acid. After that, marinization is performed. After maleation, acid anhydride stems are treated with water, alcohol, ammonia, amine, etc. to give a final acid value of 20 to 35 (or 50 to 150). When the acid value is less than 20, the water solubility is insufficient and the dispersibility is poor, and when the acid value exceeds 350, the water resistance of the formed coating film becomes poor. Neutralization and water solubilization include ammonia,
This is carried out using amines, alkali hydroxides, alkali metal salts, etc. The emulsion (b) in the present invention is obtained by emulsifying and bonding radically polymerizable unsaturated monomers in a conventional manner using the neutralized water-solubilized product (1) as a dispersion stabilizer.

Polymerization is usually carried out in a suspended solid state, but it is also possible in a static bed state after emulsification. The temperature only needs to be above the freezing point, and a polymerization initiator is not necessarily required, but in order to speed up the polymerization, a conventional initiator may be added in a conventional manner. The initiator may be any initiator as long as it generates radicals, and peroxide-based and azo-based initiators are generally used.

Examples of radically polymerizable unsaturated monomers to be emulsion-bonded in the present invention include styrene, vinyltoluene, Q-methylstyrene, butadiene, bentadiene, isoprene, chloroprene, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, and those having 1 to 26 carbon atoms. Esterified product of alcohol and methacrylic acid, esterified product of alcohol having 2 to 26 carbon atoms and acrylic acid, acrylic acid or methacrylic acid and Cardura 8
(Product name of Shell Chemical Company), glycidyl methacrylate or glycidyl acrylate and carbon number 1
Adducts of ~26 baggage oils or semi-drying oils with monocarboxylic acids other than fatty acids, esterification products of monoalkyl (1 to 5 carbon atoms) ether of ethylene glycol or diethylene glycol and acrylic acid or methacrylic acid N-butoxymethyl Acrylamide, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc. are suitable. Others include beoba monomer, vinyl acetate, vinyl chloride, vinylidene chloride, propylene, ethylene, Z-methylol acrylamide, hydroxyethyl acrylate, acrylamide tomethacrylamide, acrylic acid, methacrylic acid, acrylonitrile, methyl acrylate, vinyl pyrrolidone,
Vinylpyridine, vinylcarbazole, etc. can also be used. In emulsion polymerization, the ratio of the dispersion stabilizer and these radically polymerizable unsaturated monomers may be such that the acid value based on the total solid content is 5 to 150.

However, when acrylic acid and/or methacrylic acid is added as the radically polymerizable unsaturated monomer, the acid value thereof is not included in the calculation. The aqueous coating composition containing the neutralized water-solubilized product (1) and emulsion (0) obtained by the present invention as main components of the vehicle has room temperature curability and is suitable for obtaining a delicate coating film. .

The emulsion according to the present invention is suitable for obtaining a room-temperature curing type coating film, but it can also be heat-cured. The coating composition of the present invention is particularly characterized by excellent corrosion resistance, such as salt water resistance and salt water mist resistance, and furthermore, although it is an emulsion paint, it has brush application workability comparable to oil-based paints. It has high quality. The mixing ratio of the vehicle composition of the present invention is determined by considering the drying properties, corrosion resistance, durability, coating surface condition, etc. of the resulting coating film, and is usually determined by the weight ratio of the neutralized aqueous solubilate (1 )/Emulsion (0) White 95/5 to 5/9, preferably 90/10
It is desirable that the range is from 10/90 to 10/90.

The aqueous coating composition of the present invention has as other vehicle components:
For example, drying or semi-solid oils such as linseed oil, soybean oil, coconut oil, tung oil, safflower oil, cottonseed oil, castor oil, dehydrated castor oil, boil oil, stand oil, maleated oil, esterified oil, styrene oil, etc. Approximately 100 parts by weight of synthetic or processed oils such as synthetic oils, urethanized oils, cyclobentagenated oils, etc., based on the total solid content of the neutralized water-solubilized product (1) and the emulsion (b), which are 10 parts by weight. Preferably, it may contain 5 parts by weight or less.To prepare the coating composition of the present invention, it is sufficient to mix each component, and furthermore, a conventional pigment, aluminum powder, micaceous iron oxide, There is absolutely no problem in adding additives such as glass flakes, zinc dust, anti-rust pigments and dryers.The present invention will be explained below with reference to Examples and Production Examples.

Parts and percentages are by weight unless otherwise specified.
point to Production example 1 RJ-101 (number average molecular weight 11500 days content 7.7
% of styrene-allylic alcohol copolymer (manufactured by Monsanto Chemical) 1641%, soybean oil fatty acid 2080%, xylene 200% and dibutyltin oxide 3.
Put 3 pieces of water into a 51 4 tube flask and add 23 pieces of water while dehydrating.
The reaction was carried out at 0° C. for 10 hours to obtain a resin with an acid value of 5.47.

Then add 454 grams of maleic anhydride to 190-200
The maleation reaction was carried out at 00 for 7 hours. After removing xylene and unreacted maleic anhydride by distillation under reduced pressure, a mizuzaki ring was performed and butyl cellosolve was added to form a butyl cellosolve solution.
) was obtained. Production example 2 ASO-81 (number average molecular weight 114 or more, OH content 7.
44% styrene-allylic alcohol copolymer (manufactured by Daicel ■) 1641, 1905 of linseed oil, 183 of xylene and 3.3 of dibutyltin oxide were placed in a 51-liter flask and heated to 230 while dehydrating.
The reaction was carried out at midnight for 6 hours to obtain a resin with an acid value of 4 Li0.

Add 433 grams of maleic anhydride to this and heat to 190-200℃.
After heating for 4 hours to perform a maleation reaction and removing xylene and unreacted anhydrous maleic by distillation under reduced pressure, this was ring-opened with water and 3-methyl-3-methoxybutanol was added to obtain a resin (with a total acid value of 90 and solid content of 79%). b) was obtained. Manufacturing example
3 Pour 1,760 g of xylene into a No.51 4 flask and add 1
While worshiping the light at 30qo, n-butyl methacrylate 9
A mixture of 909 and 45M of 2-hydroxyethyl methacrylate and a mixture of 40M of xylene and 100M of azobisdimethylvaleronitrile are added dropwise from separate dropping funnels over a period of 2 hours.

One hour after the completion of the dropping, 20 hours of azobisisobutyronitrile was added, and the temperature was maintained at 130°C for an additional 3 hours. After adding 960 g of linseed oil fatty acid and 4 g of dibutyltin oxide, an esterification reaction was carried out at 230 p.m. for 6 hours while dehydrating to obtain a resin with an acid value of 1.6.

To 600 parts of this resin, 250 parts of maleic anhydride is added and reacted for 7 hours from 170 to 180 parts in a mixed solvent of 300 parts of an ester solvent and 200 parts of xylene. After the reaction, remove the solvent and unreacted maleic anhydride under reduced pressure, open the ring with water, add butyl cellosolve, and reduce the total acid value to 1.
29 Resin (c) having a solid content of 80% was obtained. Production Example 4 200 g of the resin (a) obtained in Production Example 1 was added to 0.95 g of ammonia.
An equivalent amount of neutralized and dissolved in 769 liters of water was added, and 16 liters of butyl cellosolve was added and thoroughly dissolved. Next, 414 liters of n-butyl methacrylate was added and thoroughly stirred.

After thorough emulsification, 20 days of water in which ammonium persulfate was dissolved was added. Next, heating was started while shaking the mixture, and the reaction was carried out for 2 hours while maintaining the temperature at 80 CO to obtain an emulsion (A) with a solid content of 39.8%. Production Example 5 0.95 equivalents of the resin (b) obtained in Production Example 2 was neutralized with ammonia in an amount of 0.95 equivalents, and dissolved in 769 grams of water.
Furthermore, after adding and dissolving 14 minutes of butyl cellosol, n-
Add 414 ml of butyl methacrylate and mix well to make an emulsion, then add 1 ml of ammonium persulfate to 2 ml of water.
Add the melted ingredients in the evening and heat while stirring carefully.8
The emulsion with a solid content of 39.9% was kept at 8℃ for 2 hours (
b) was obtained.

Production Example 6 200ml of the solution of resin (c) obtained in Production Example 3 was neutralized with 0.95 equivalents of ammonia, and dissolved in 769ml of water.

Furthermore, add 16 minutes of butyl cellosolve, and after lighting the lamp well,
Add 207 grams of styrene and 207 grams of 2-ethylhexyl methacrylate, stir well and make an emulsion, then add 1 ounce of ammonium persulfate dissolved in 20 ounces of clean water, heat while keeping the lamp lit, and heat until 80 pm. The mixture was kept for 2 hours to obtain an emulsion (c) with a solid content of 39.8%. Reference example number: Maleinated 1 with an average molecular weight of about 3000 and an acid value of 100,
A 74% solid content butyl cellosolve solution of 2-vinyl type polybutadiene was neutralized by 0.95% with ammonia to 78%
0 Dissolve in evening water.

Add 414 grams of n-butyl methacrylate to this, mix well to form an emulsion, then add 12 grams of ammonium persulfate dissolved in 20 grams of water and heat.
Emulsion with solids content of 39.7% kept at ℃ for 2 hours (d)
I got it. Example 1 The resin (a) obtained in Production Example 1 was neutralized by adding 17 hours of 28% ammonia water to 92 hours, and then decomposed with water for 184 hours to make an aqueous solution of resin (a) with a solid content of 25%. .

To this resin (a) aqueous solution, titanium oxide 1942, sodium tripolyphosphate 0.5 hours, and antifoaming agent Antiform B (trade name, manufactured by Toray Silicon ■, the following items are omitted) 2 hours are uniformly mixed using a sushi machine. and pass it through a sand mill to a particle size of 10r.
A pigment paste was obtained. Next, production example 4
Emulsion (A) 4239 obtained in 4239, 10% polyvinylpyrrolidone aqueous solution 3 times, and tap water 8 times were mixed, and while stirring, pigment paste 488 times, cobalt naphthenate, and lead naphthenate were mixed in metal amounts of 0.3 and 0.3, respectively. The mixture was added for 0.7 minutes and mixed until uniform to obtain a paint. Example 2 Solution of resin (a) obtained in Production Example 1 137 Turquoise 28
After neutralizing by adding 25% of ammonia water, 52% of water was added to make an aqueous solution of resin (a) with a solid content of 65%.

This resin (a) aqueous solution 167 times, iron oxide 70 times, talc 33 times, tankar 91 times, calcium molybdate 10 times
The metal content of cobalt naphthenate, lead naphthenate, and manganese naphthenate is 0.95 and 0.93, respectively.
0.95 mm, antifoam B2 antifoam, 20 mm of stand oil (linseed oil) maleide, and 20 mm of lupitor acetate were placed in a ball mill and dispersed until the particle size was 30 mm to make a pigment paste. I got it.

Next, this pigment paste was added to the emulsion 547 obtained in Production Example 5 while mixing uniformly to obtain a paint.

Examples 3-6 Paints were prepared in the same manner as in Examples 1 and 2.

The formulation is as shown in Table 1. Comparative Example 1 Malenization 1 with a number average molecular weight of about 3000 and an acid value of 100,
99 grams of a 74% butyl cellosolve solution of 2-vinyl polybutadiene was neutralized by adding 22 grams of 28% ammonia water, and then 172 grams of water was dissolved to obtain a 25% aqueous solution.

To this aqueous resin solution, 194 mm of titanium oxide, 0.5 mm of sodium tripolyphosphate, and 0.5 mm of antifoaming agent were uniformly mixed in a simulator, and the mixture was dispersed through a sand mill until the particle size reached 10 mm to obtain a pigment paste. Ta. Next, 424 parts of the emulsion (d) obtained in the reference example, 30 parts of a 10% polyvinylpyrrolidone aqueous solution, and 8 parts of clean water were mixed, and while stirring, 488 parts of the pigment paste, cobalt naphthenate, and lead naphthenate were mixed. were added in metallic amounts of 0.3 and 0.7 days, respectively, and stirred until uniform to obtain a paint.
Comparative Example 2 A 74% butyl cellosolve solution of maleated 1,2-vinyl polybutadiene with a number average molecular weight of about 3000 and an acid value of 100 was added with 146 g of triethylamine and 19 g of triethylamine for neutralization, and then dissolved in water with a solid content of 25%. An aqueous resin solution was prepared.

This resin aqueous solution contains 200 parts of iron oxide and 1 part of calcium phosphate.
00 evening, L-2 stand oil (manufactured by Nisshin Oil) 20 evening, antifoaming agent antiform B2 evening, 10% polyvinylpyrrolidone 2
0 parts, butyl cellosolve 20 parts, 15% lead naphthenate 5.0 parts, 5% cobalt naphthenate 5.0 parts are uniformly mixed in a sand mill, passed through a sand mill, and dispersed until the particle size becomes 30 parts to make a pigment paste. I got it.

Next, the emulsion (d) 547 obtained in the reference example was weighed out, and the pigment paste 804 was added while stirring, and the mixture was mixed until homogeneous to obtain a paint.

The aqueous coating compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were applied to a mild steel plate of size 150 x 70 x 0.8 to a dry thickness of 45 to 50 degrees. 20 0
The samples were dried for 7 days at a relative humidity of 75% and subjected to a coating acid performance test.

Coating film performance test method Water resistance: The coating film was immersed in 20 qo of clean water and the presence or absence of any abnormality occurring on the coating film was observed.

Salt water resistance: The coating film was immersed in 3% saline solution at 20° C. and the presence or absence of abnormalities occurring on the coating film was observed.

Salt water mist resistance: A test plate with a cross cut cut down to the substrate was placed in a salt water mist device spraying 5% salt water at 35°C, and the presence or absence of abnormalities on the coating film was observed. .

Outdoor peelability: A test plate with a cross cut that reached the substrate was peeled outdoors, and the presence or absence of abnormalities on the coating film was observed.

The workability test was conducted as follows.

A horsehair flat brush was used on a 900 x 600 x 6 slate board having a coating film of vinyl acetate homopolymer emulsion paint, and the degree of brush removal was observed. The test results are shown in Table 2, and the water of the present invention. It can be seen that the coating composition has excellent performance.

Table 2

Claims (1)

[Scope of Claims] 1. Neutralized water-solubilized product of a maleated or partially maleated addition polymer having a drying oil fatty acid residue and/or a semi-drying oil fatty acid residue connected to the main chain by an ester bond as a side chain. (I) and an emulsion (II) obtained by emulsion polymerization of a radically polymerizable unsaturated monomer using the neutralized water-solubilized product (I) as a dispersion stabilizer. 2. In the aqueous coating composition according to claim 1, the drying property of the addition polymer having as a side chain a drying oil fatty acid residue and/or a semi-drying oil fatty acid residue connected to the main chain by an ester bond. oil fatty acids and/or
Or the amount of semi-drying oil fatty acid is 10 to 9 in terms of fatty acid oil length.
Something that is 0.