JPH09176252A - Water-dispersible resin composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-dispersible resin compsn. which can give a water- base coating material having good applicability and dispersion stability and capable of forming a coating film excellent in clarity, smoothness, resistances to chemicals and water, and water-repellent properties and to provide a process for producing the same. SOLUTION: A mixture comprising 10-95wt.% polysiloxane having a polysiloxy moiety in the main chain and 5-90wt.% monomer mixture comprising 2-75wt.% ethylenically unsatd. monomer having an acid group and 25-98wt.% other ethylenically unsatd. monomer is subjected to free-radical polymn. in the presence of a polymn. initiator. Then the resultant acidic resin compsn. is neutralized with a neutralizing agent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water-dispersible resin composition, and more particularly to a water-dispersible resin composition which can be preferably used as a coating composition and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Paints generally include colorants such as dyes and pigments, a binder that secures them to the coated surface, and a liquid medium for uniformly coating them. Since the binder is a high molecular weight polymer or resin, it is often water-insoluble in nature, but organic solvents such as thinners have been mainly used as liquid media in paints containing such water-insoluble binders. .

However, in recent years, there is an increasing demand for water-based paints that do not adversely affect the environment and are harmless to workers.
Many water-soluble or water-dispersible paints have been reported so far, but water-soluble paints have the drawback of being essentially inferior in water resistance. It has bad drawbacks.

The cause of poor stability of the water-dispersible paint is that the dispersion stability of the water-dispersible resin composition mainly used for the water-dispersible paint is poor.

For example, JP-A-52-47029 discloses a mixture of an alkoxymethyl acrylamide, an α, β-ethylenically unsaturated carboxylic acid and another copolymerizable ethylenically unsaturated monomer in the presence of a water-soluble resin. A water-dispersible resin composition in which a copolymer obtained by underpolymerization is neutralized is disclosed. However, since the compatibility between the water-soluble resin and the copolymer is insufficient in this system, the obtained resin composition is inferior in water dispersion stability. Therefore, the paint using this is inferior in coating workability and is apt to sag. Further, the obtained coating film is inferior in transparency, smoothness, chemical resistance, water resistance and water repellency.

Further, in JP-A-3-504138, (a) a monomer mixture containing an acrylic monomer having a carboxyl group and (b) a monomer mixture containing an acrylic monomer having a hydroxyl group are polymerized alternately. Although a water-dispersible resin composition obtained by the addition is disclosed,
Since the compatibility between the polymer having an acid value and the polymer having no acid value is insufficient, this resin composition is inferior in water dispersion stability. Therefore, the paint using this does not sufficiently develop the structural viscosity. Moreover, it has poor chemical resistance.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object thereof is to provide a coating excellent in transparency, smoothness, chemical resistance and water resistance, particularly water repellency. It is an object of the present invention to provide a water-dispersible resin composition capable of forming a film and realizing an aqueous paint having good coating workability and dispersion stability, and a method for producing the same.

[0008]

The present invention is directed to (a) 10 to 95% by weight of a polymer or copolymer having a polysiloxy moiety; and (b) (2) 2 to 75% by weight of an ethylenically unsaturated monomer having an acid group. And (2) Other ethylenically unsaturated monomers 2
5 to 90% by weight of a monomer mixture consisting of 5 to 98% by weight;
A starting mixture containing a step of radical polymerization in the presence of a polymerization initiator, and the resulting acid group-containing resin composition,
The present invention provides a method for producing a water-dispersible resin composition including a step of neutralizing by adding a neutralizing agent, whereby the above object is achieved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, first, a polymer or copolymer having a polysiloxy moiety, or a solution obtained by dissolving the polymer or copolymer in an organic solvent is heated to about 80 to 140 ° C., preferably 9 to 90 ° C.
Heat to 0-120 ° C.

The term "polymer or copolymer having a polysiloxy moiety" includes polysiloxanes and polysiloxane-modified resins.

As used herein, the term "polysiloxane" means
Formula in the main chain

Embedded image [In the formula, each R is independently [ meaning that it may be different.
It's a taste. ] It is a residue of an organic group such as an alkyl group and a phenyl group, and n is an integer of 3 or more. ] The polymer and copolymer which have the polysiloxy part shown with these.

In the copolymer having a polysiloxy moiety in the main chain, the structure of the polymer main chain other than the polysiloxy moiety is not particularly limited, but it is preferably polyether, polyester or polycarbonate. This is because the presence of a functional portion having a strong cohesive force such as an ether portion, an ester portion and a carbonate portion in the copolymer enhances the strength of the obtained coating film.

The number average molecular weight of the polysiloxane is preferably 500 to 20000, more preferably 1000 to 10000. When the number average molecular weight is less than 500, the resulting coating film may have poor water repellency. If it is less than 1000, the curability may be poor. If it exceeds 20000, the reaction may not occur uniformly during polymerization.

The polysiloxane preferably has 5 or more, preferably 10 or more siloxy moieties continuously in the main chain. If the number of siloxy moieties is less than 5, the resulting coating film may have poor water resistance. If the number is less than 10, sufficient water repellency may not be obtained when a cured film is formed.

Generally, the content of the polysiloxy moiety in the polysiloxane is preferably 20% by weight or more, more preferably 30% by weight or more. The content of polysiloxy part is 20% by weight
If it is below the range, the water repellency of the resulting coating film will be poor.

Examples of polysiloxy moieties include dimethylpolysiloxy moieties, diphenylpolysiloxy moieties and methylphenylpolysiloxy moieties.

Specific examples of the polysiloxane preferably usable in the present invention include "SH200" manufactured by Toray Dow Corning,
Examples include “SH510”, “BY16-817” and “BY16-876”, and “TSF456”, “TSF400” and “TSF433” manufactured by Toshiba Silicone Co., Ltd.

Silicone oils having various functional groups, for example, alkyl-modified silicone oil "BY16-846" (manufactured by Toray Dow Corning), amino-modified silicone oil "TSF4700" (manufactured by Toshiba Silicone), carboxyl-modified silicone oil " TSF4770 "(manufactured by Toshiba Silicone), epoxy modified silicone oil" TSF4730 "(manufactured by Toshiba Silicone)," SF8421 "(manufactured by Dow Corning Toray), carbinol modified silicone oil" SF8427 "and" SF8428 "(manufactured by Toray) And a polysiloxane resin having a polyether moiety, such as polyether-modified silicone oils "TSF4440", "TSF4460" (manufactured by Toshiba Silicone Co., Ltd.) and "KF945" (manufactured by Shin-Etsu Chemical Co., Ltd.). Can be used as the polysiloxane.

As used herein, the term "polysiloxane-modified resin" means a water-insoluble resin containing polyester, polyether, polycarbonate, polyurethane, epoxy resin, acrylic resin and a mixture thereof, and a polysiloxane having a high polysiloxy moiety content. The resin obtained by modification with (2) is also called a modified silicone vehicle.

In the present specification, the "water-insoluble resin" means water.
A resin having a solubility of 1 g or less per 100 g. The use of such a resin makes it possible to provide a coating film having excellent water resistance as compared with the case of using a water-soluble resin.

The water-insoluble resin is not particularly limited as long as it is a non-volatile liquid at the polymerization temperature and is used as a binder for paints by those skilled in the art, but preferably has a molecular weight of 300 to 100,000, more preferably 1000 to 50000. , And preferably a hydroxyl value of 10 to 400, more preferably 20 to 200.
Having. If the molecular weight is less than 300, the resin may become volatile and may be lost by heating. If it exceeds 100,000, the resin may not be liquefied even at the polymerization temperature. When the hydroxyl value is less than 10, the resulting coating film may have poor curability, and when it is 400 or more, it may be water-soluble.

The term "polysiloxane having a high polysiloxy moiety content" means 40% by weight or more, preferably 6% by weight in the resin.
It refers to a polysiloxane having 0% by weight or more of a polysiloxy moiety. For example, the commercially available products already exemplified as the polysiloxane and silicone oil which can be preferably used in the present invention are included therein.

The term "modified" means that a functional group contained in the water-insoluble resin is reacted with a functional group contained in the polysiloxane to form a chemical bond therebetween. For example, in a polyester modified with an epoxy-modified silicone oil (for example, "TSF4730" manufactured by Toshiba Silicone Co., Ltd.), an epoxy group in the epoxy-modified silicone oil reacts with a carboxyl group in the polyester,
A chemical bond is formed between the epoxy-modified silicone oil and the polyester.

The polysiloxane-modified resin preferably has a polysiloxy moiety content of 20% by weight or more, particularly 30% by weight or more. When the content of the polysiloxy portion is less than 20% by weight, the water repellency of the obtained coating film is poor.

Polyesters are synthesized by polyesterification of polyols with polycarboxylic acids or acid anhydrides. Preferably, it is further synthesized from an acid component containing a long chain fatty acid. Examples of polyols include trimethylolpropane, triols such as hexanetriol, propylene glycol, hexylene glycol, hydrogenated bisphenol A, caprolactone diol and diols such as bishydroxyethyl taurine.

Examples of polycarboxylic acids include phthalic acid,
Tetrahydrophthalic acid, adipic acid, trimellitic acid and the like can be mentioned. Corresponding acid anhydrides are also preferably used. Examples of long chain fatty acids used include saturated fatty acids such as stearic acid and lauric acid, unsaturated fatty acids such as oleic acid and myristic acid, and natural fats and oils such as castor oil, palm oil and soybean oil and their Examples include modified products.

Polyethers include alkylene oxide polymers such as ethylene oxide and propylene oxide, and their adducts with polyols. Examples of polyols include triols such as trimethylolpropane and hexanetriol, hydrogenated bisphenol A, caprolactone diol and diols such as bishydroxyethyl taurine.

The polycarbonate is preferably a resin obtained by the reaction of a carbonate selected from dialkyl carbonates and ethylene carbonate with an alcohol selected from linear dihydric alcohols, branched dihydric alcohols and polyhydric alcohols having 3 or more valences.

Specific examples of the branched chain dihydric alcohol include:
2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2,2-diethyl-
1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,2,4-
Trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, 1,4-dihydroxyethylbenzene, 1,4-dihydroxyethyloxybenzene, Screw
Aliphatic diols such as (4-hydroxyethyloxyphenyl) propane and bis (4- (2-hydroxypropyl) oxyphenyl) propane, and bisphenol A, bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) ) Undecane and di (3-hydroxyphenyl)
A typical example is bisphenol such as ether.

Typical examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, a trimethylolpropane dimer, and pentaerythritol.

Specific examples of the straight chain dihydric alcohol include 1,
Typical examples are 3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol. As.

Polyurethane is obtained by the reaction of a diol and a diisocyanate compound. A polyether diol or a polyester diol is generally used as the diol. Examples of such compounds include those obtained by polymerizing or copolymerizing alkylene oxide, (ethylene oxide, propylene oxide, methylene oxide, etc.) and / or heterocyclic ether (tetrahydrofuran, etc.), for example, polyethylene glycol, polypropylene glycol, polyethylene. -Propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol; polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, poly-3-methylpentyl adipate, polyethylene / butylene Adipate, polyneopentyl / hexyl adipate; polylactone diol, eg polycaprolactone diol, poly-3 -Methylvalerolactone diols; polycarbonate diols; or mixtures thereof, as well as diols containing acid groups such as dimethylolpropionic acid.

Diisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate; alicyclic diisocyanates having 4 to 18 carbon atoms, such as 1,4-cyclohexane diisocyanate and 1-isocyanato-. 3-Isocyanatomethyl-3,5-trimethylcyclohexane (isophorone diisocyanate), 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexylene diisocyanate, isopropylidene dicyclohexyl
-4,4'-diisocyanate; modified products of these diisocyanates; and mixtures thereof. Preferred examples of these include hexamethylene diisocyanate, isophorone diisocyanate, aromatic diisocyanate, and the like.

Examples of epoxy resins are ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, preferably trimethylolpropane triglycidyl ether, bisphenol A-diglycidyl ether and hydrogenated. Glycidyl ethers such as bisphenol A-diglycidyl ether, adipic acid, diglycidyl ester, hydrogenated phthalic acid diglycidyl ester, phthalic acid diglycidyl ester and preferably trimellitic acid triglycidyl ester, and 3, Such as 4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate and vinylcyclohexene dioxide Cyclic epoxy, and the like. ERL-4221 (UCC), 4299 (UCC), Epolite 1600 (Kyoeisha Yushi) and 4000 (Kyoeisha Yushi), Denacol EX-301, 622, 512 and 421 (Nagase Kasei) Commercially available products such as manufactured products can also be used. The epoxy resin may be a polymer.

Acrylic resins include various (meth) acrylic acid esters, (meth) acrylic acid, ethylenically unsaturated monomers such as maleic acid and maleic acid esters, and aromatic vinyl such as styrene and α-methylstyrene. Homopolymers and copolymers of compounds.

Examples of ethylenically unsaturated monomers are acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, maleic acid monoethyl ester, fumaric acid monoethyl ester, itaconic acid monoethyl ester. Carboxyl group-containing monomers such as esters, succinic acid mono (meth) acryloyloxyethyl ester and phthalic acid mono (meth) acryloyloxyethyl ester; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, 4 -Hydroxyl group-containing monomers such as hydroxybutyl methacrylate and their reaction products with lactones;
And non-functional monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate.

The number average molecular weight of the acrylic resin is 1,000 to 1,000.
00, preferably 2000 to 50000, more preferably 5000 to 1
Set to 0000. If the number average molecular weight is less than 1000, the resulting coating film may have insufficient curability. If it exceeds 100000, the polymerization may not proceed uniformly.

The acid value of the acrylic resin is 50 or less, preferably
20 or less. If the acid value exceeds 50, the water repellency of the resulting coating film may decrease.

The hydroxyl value of the acrylic resin is 10 to 10
It is set to 0, preferably 20 to 80. If the hydroxyl value is less than 10, the curability of the resulting resin composition may be reduced, and if it exceeds 100, the water resistance of the resulting coating film may be poor.

Specific examples of the acrylic resin include, for example, butyl acrylate (60 parts by weight), methacrylic acid (2 parts by weight), 2-hydroxyethyl methacrylate (10 parts by weight) and styrene (28 parts by weight) mixed with xylene (100 parts by weight). Examples include those obtained by adding 5 parts by weight of Kayaester 0, a peroxide polymerization initiator manufactured by Yakuzo Co., Ltd., and polymerizing.

Specific examples of the polysiloxane-modified resin that can be preferably used in the present invention include, for example, "YR3300" and "TSR18" manufactured by Toshiba Silicone Co., which are called silicone alkyd.
4 "," TSR187 "made by Toshiba Silicone called Silicone Polyester and" SR2 made by Toray Dow Corning "
Polysiloxane-modified polyesters such as 108 ";and" TSR170 "from Toshiba Silicone Co. and" K "from Shin-Etsu Chemical Co., Ltd.
Examples include polysiloxane-modified acrylic resin such as "R9706".

The polysiloxane or polysiloxane modified resin is used in an amount of 10 to 95% by weight, preferably 25 to 95% by weight, more preferably 55 to 95% by weight, based on the total amount of the starting mixture. If the amount of polysiloxane or the like is less than 10% by weight, the smoothness, chemical resistance and water repellency are not improved. If it exceeds 95% by weight, the dispersion stability of the coating composition and the curability of the coating film deteriorate.

In the method of the present invention, a heated
The monomer mixture is added to a polymer or copolymer having a polysiloxy moiety, or a solution obtained by dissolving this in an organic solvent, and the resulting starting mixture is polymerized in the presence of a polymerization initiator. The polymerization is preferably carried out for 1 to 8 hours, especially 2 to 6 hours. In a preferred embodiment, the monomer mixture and the polymerization initiator are simultaneously added to a solution such as polysiloxane for 1 to 5 hours,
It is preferably added dropwise over 2 to 3 hours, and then the polymerization temperature is maintained for 0 to 4 hours, preferably 1 to 2 hours.

The monomer mixture used in the present invention comprises an ethylenically unsaturated monomer having an acid group and other ethylenically unsaturated monomers. The ethylenically unsaturated monomer having an acid group is not particularly limited as long as it can provide water dispersibility to the polysiloxane or the polysiloxane-modified resin in neutralization, but one having up to 6 carbon atoms in the molecule is used. preferable. This is because if the number of carbon atoms in the molecule exceeds 6, hydrophilicity will not be favorably provided.

The ethylenically unsaturated monomer having an acid group used in the present invention is an ethylenically unsaturated monomer having a carboxyl group, a sulfonic acid group or a phosphoric acid group. This is because the polysiloxane has an acid strength necessary for imparting water dispersibility.

Specific examples of the ethylenically unsaturated monomer having a carboxyl group include acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid and their half-esterified products, maleic acid ethyl ester, Examples include fumaric acid ethyl ester, itaconic acid ethyl ester, succinic acid mono (meth) acryloyloxyethyl ester and phthalic acid mono (meth) acryloyloxyethyl ester, and mixtures thereof.

Specific examples of the ethylenically unsaturated monomer having a sulfonic acid group include acrylamido t-butyl sulfonic acid, acrylic acid 3-sulfonylpropyl ester, methacrylic acid 3-sulfonylpropyl ester and itaconic acid bis (3-sulfonylpropyl). ) Ester etc. are mentioned.

Specific examples of the ethylenically unsaturated monomer having a phosphoric acid group include acid phosphoxyethyl methacrylate, acid phosphoxypropyl methacrylate and acid phosphoxy 3-chloropropyl methacrylate.

The ethylenically unsaturated monomer containing acid groups is used in an amount of 2 to 75% by weight, preferably 4 to 75% by weight, more preferably 15 to 50% by weight, based on the total amount of the monomer mixture. If the amount of the ethylenically unsaturated monomer having an acid group is less than 2% by weight, the dispersibility becomes poor, and if it exceeds 75% by weight, the polymerization may not proceed uniformly.

The other ethylenically unsaturated monomer is not particularly limited as long as it does not impair the water dispersibility imparted to the polysiloxane or the like by the acid group-containing monomer and can coexist with the acid group. The ethylenically unsaturated monomers having are preferred. The ethylenically unsaturated monomer having an amide group preferably has up to 12 carbon atoms in the molecule. If the number of carbon atoms in the molecule exceeds 12, the resulting resin will not be provided with good hydrophilicity.

Specifically, (meth) acrylamides such as acrylamide, methacrylamide, N-isopropylacrylamide, N-butylacrylamide, N, N-dibutylacrylamide or hydroxymethylacrylamide, methoxymethylacrylamide and butoxymethylacrylamide.
Acrylamide is used. Preferred (meth) acrylamides are acrylamide, methacrylamide and mixtures thereof.

The ethylenically unsaturated monomer having an amide group is 2 to 50% by weight based on the total amount of the monomer mixture,
It is preferably used in an amount of 10 to 30% by weight. If the amount of the ethylenically unsaturated monomer having an amide group is less than 1% by weight, the dispersibility becomes poor, and if it exceeds 50% by weight, the polymerization may not proceed uniformly.

Other ethylenically unsaturated monomers are not particularly limited as long as they do not impair the water dispersibility of the acid group-containing resin composition obtained after polymerization, and include, for example, an ethylenically unsaturated monomer having a hydroxyl group. Be done. By using these, a hydroxyl group is introduced into the water-dispersible resin composition of the present invention, and better curability of the coating film can be obtained.

Specific examples thereof include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, and reaction products thereof with lactone.

The ethylenically unsaturated monomer having hydroxyl groups is used in an amount of 5 to 60% by weight, preferably 10 to 40% by weight, based on the total amount of the monomer mixture. If the amount of the ethylenically unsaturated monomer having a hydroxyl group is less than 5% by weight, curability will be poor, and if it exceeds 60% by weight, uniform polymerization may not be possible.

In addition, styrene, α-methylstyrene,
Acrylic acid esters (for example, methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate) and methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-methacrylate) -Butyl,
Non-functional monomers such as 2-ethylhexyl methacrylate and lauryl methacrylate) can be used as other ethylenically unsaturated monomers.

The non-functional monomer is used in an amount of 10 to 93% by weight, preferably 30 to 90% by weight, based on the total weight of the monomer mixture. If the amount of the non-functional monomer is less than 10% by weight, the polymerization will not proceed uniformly, and if it exceeds 90% by weight, the dispersibility will be poor.

The monomer mixture comprising the above-mentioned ethylenically unsaturated monomer having an acid group and other ethylenically unsaturated monomers is 5 to 90 based on the total amount of the starting mixture.
% By weight, preferably 5-75% by weight, more preferably 5-
Used in an amount of 45% by weight.

The polymerization initiator used in the present invention is not particularly limited as long as it is generally used as a radical polymerization initiator. For example, organic peroxides such as benzoyl peroxide, t-butyl peroxide and cumene hydroperoxide. And azobiscyanovaleric acid and organic azo compounds such as azobisisobutyronitrile.

The acid group-containing resin composition obtained after the completion of the polymerization has an acid value of 5 to 200, especially 20 to 100, and a hydroxyl value of 10 to 300, especially 2
It is preferable to have 0 to 200. If the acid value is less than 5, it becomes water-insoluble, and if it exceeds 200, the progress of polymerization becomes uneven. Further, if the hydroxyl value is less than 10, the curability becomes poor,
If it exceeds 300, dispersibility will be poor. The acid value is adjusted by increasing or decreasing the amount of the monomer having an acid group, and the hydroxyl value is adjusted by increasing or decreasing the amount of the monomer having a hydroxyl group.

Polymerization is carried out at 80 to 140 ° C., preferably 90 to 120 ° C.
At a temperature of 1 to 8 hours, preferably 2 to 4 hours, by operations well known to those skilled in the art. For example, a monomer mixture and a polymerization initiator are added dropwise to the above-mentioned polysiloxane or polysiloxane-modified resin in which an appropriate amount of an organic solvent is contained to adjust the viscosity and then heated.

The organic solvent is generally used in an amount of 100 parts by weight or less, preferably 10 to 50 parts by weight, based on 100 parts by weight of the polysiloxane or the polysiloxane-modified resin. If the amount of the organic solvent exceeds 100 parts by weight, the molecular weight of the acrylic polymer obtained will decrease, and as a result, the curability of the water-dispersible resin composition will decrease.

The organic solvent dissolves polysiloxane and the like.
It is preferably about 60 to 250 ° C. Suitable organic solvents include butyl acetate, xylene, toluene and water-insoluble organic solvents such as methyl isobutyl ketone; and tetrahydrofuran, ethanol, methanol, n-butanol, propanol, isopropanol, 2-butanol,
t-Butyl alcohol, dioxane, methyl ethyl ketone, ethylene glycol, ethylene glycol monobutyl ether, 2-methoxypropanol, 2-ethoxypropanol, 2-butoxypropanol, diethylene glycol monobutyl ether, butyldiglycol, N-methylpyrrolidone, ethylene carbonate and propylene carbonate. Water-miscible organic solvents such as Water-miscible organic solvents are particularly preferred.

Then, a neutralizing agent is added to neutralize at least a part of the acid groups contained in the resin composition. This imparts water dispersibility to the acid group-containing resin composition to obtain the water dispersible resin composition of the present invention.

The neutralizing agent used in the present invention is not particularly limited as long as it is generally used for neutralizing the acidic groups contained in the aqueous or water-dispersible resin composition when it is prepared. , Specifically, organic amines such as monomethylamine, dimethylamine, trimethylamine, triethylamine, diisopropylamine, monoethanolamine, diethanolamine and dimethylethanolamine, and inorganics such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Examples thereof include bases.

The neutralizing agent may be used in the amounts normally used for preparing acid-functional water-dispersible resins, but is preferably 2 to 30% by weight, preferably 5% by weight, based on the resin solids content before neutralization. ~ 20% by weight.

The resulting water-dispersible resin composition of the present invention is well dispersed in an aqueous medium to form a stable dispersion. The aqueous medium refers to water or a mixed solution of water and a water-miscible organic solvent. When using a mixed solution of water and a water-miscible organic solvent, water and a water-miscible organic solvent is 100/0 to 60/4 from the viewpoint of reducing the amount of the volatile organic solvent contained in the composition.
It is preferable to blend in a weight ratio of 0, particularly 100/0 to 80/20. Preferred water-miscible organic solvents include those mentioned above as the organic solvent during the polymerization step.

By adding a curing agent, a pigment and other known additives to the resulting aqueous resin dispersion, an aqueous coating composition exhibiting good dispersion stability can be obtained.

The curing agent is not particularly limited as long as it is a crosslinking agent generally known to crosslink hydroxyl groups or acid groups present in the dispersed resin. It is preferable to use at least one of an amino compound, an isocyanate compound and an epoxy compound.

Specifically, it is a blocked polyisocyanate, an alkoxylated melamine formaldehyde condensate (an alkoxide of a condensate of melamine formaldehyde or paraformaldehyde, such as methoxymethylol melamine, isobutoxylated methylol melamine and n-butoxylated). Methylol melamine), and an epoxy compound containing two or more epoxy groups (for example, "Epicoat 828", "1001" and "100" manufactured by Shell Chemical Co., Ltd.
4 ", Kyoei Yushi Co., Ltd.'s" Epolite 40E "," 400E ","# 1 "
"600", "Same # 721", "Denacol EX-30" manufactured by Nagase Kasei Co., Ltd.
1 "," D. 622 "," D. 512 ", and" D. 421 ", etc.), and these may be used as a mixture.

As the pigment, usual inorganic pigments, organic pigments and metal pigments (for example, aluminum pigments) can be used in appropriate amounts. Examples of additives include an anti-UV agent, an antifoaming agent,
Surface preparation agents and the like can be mentioned. Known polymer emulsion resins, water-soluble acrylic resins, polyesters, alkyd resins and epoxy resins can also be added to the aqueous coating composition of the present invention.

By using the aqueous coating composition of the present invention, a multilayer coating film having a good appearance can be formed. An example of a preferred multilayer coating is shown in FIG. In FIG. 1, a multilayer coating film 1 is provided on an object to be coated 2 such as the body of an automobile. A base layer such as an electrodeposition layer and an intermediate coating layer may be provided on the surface of the article 2 to be coated.

The multilayer coating film 1 is mainly composed of a base coating film 3 provided on the article to be coated 2 and a clear coating film 4 provided on the base coating film 3. It is preferable that the multilayer coating film is formed by a so-called 2 coat / 1 bake coating method in which after applying the base paint, the clear paint is repeatedly applied without being cured, and the base paint and the clear paint are combined and cured. .

The base coating film 3 is formed by brush coating, spray coating, electrostatic coating, flow coating, dip coating or roller coating using the aqueous coating composition of the present invention containing a pigment and the above-mentioned usual additives. Generally 10 to
The thickness is 30 μm, preferably 10 to 20 μm. If desired, the base coating 3 may be treated before forming the clear coating 4 thereon in order to obtain a multilayer coating 1 of good appearance. For example, the appearance of the multilayer coating film 1 obtained by performing a so-called preheat treatment in which the provided base coating film 3 is heated at 50 to 100 ° C. for 2 to 3 minutes is further improved.

The clear coating film 4 is generally from 20 to 80 μm, preferably from 20 to 60 μm, using a conventional solvent-based or water-based so-called clear coating material in the same manner as the base coating film 3.
Formed to a thickness of Preferably, the clear coating film 4 is formed by using the clear coating material prepared by the aqueous coating composition of the present invention.

When the clear coating film 4 is formed by using the water-based clear coating material, it is not necessary to use a solvent for forming the multilayer coating film 1, so that the problem of environmental pollution hardly occurs. When a clear coating containing the water-dispersible resin composition of the present invention is used as the clear coating, workability, appearance and adhesion of the coating are further improved.

After forming the clear coating film 4, the base coating film 3 and the clear coating film 4 are cured to obtain the multilayer coating film 1. Curing is generally carried out by heating at a temperature of 100 to 200 ° C for 15 to 60 minutes.

[0078]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Unless otherwise specified, “parts” are based on weight.

Example 1 A polyether polysiloxane "SF8428" (manufactured by Dow Corning Toray, hydroxyl equivalent: 1600) was added to a 5 liter Kolben equipped with a stirrer, a nitrogen inlet tube, a temperature controller, a condenser and a dropping funnel. Parts and butyl diglycol 10
0 part was charged and the temperature was raised to 120 ° C.

In a dropping funnel, 300 parts of styrene, 250 parts of ethyl acrylate, 150 parts of 2-hydroxyethyl methacrylate,
A monomer mixture consisting of 223 parts of 2-ethylhexyl acrylate and 77 parts of methacrylic acid and 30 parts of Kayaester 0 (a peroxide polymerization initiator manufactured by Kayaku Akzo Co., Ltd.) were charged. The monomer mixture and the initiator were added dropwise over 3 hours while maintaining the temperature at 120 ° C. After the dropping, the temperature was further maintained at 120 ° C. for 2 hours. Dimethylethanolamine 80 parts and deionized water 17
An opaque and viscous resin solution was obtained by adding 40 parts and dissolving.

The resin solution thus obtained had a solid content of 40%, a solid content acid value of 43, and a hydroxyl value of 60. Dilute this with deionized water in a No. 4 Ford cup for 30 seconds and then at 40 ° C.
The state after standing for 10 days was visually evaluated. Uniform dispersion was confirmed immediately after dilution and after the storage stability test.

Example 2 A polyester polysiloxane "TSR180" (manufactured by Toshiba Silicone Co., acid number 9.) in a 5-liter Kolben equipped with a stirrer, a nitrogen inlet tube, a temperature controller, a condenser, and a dropping funnel.
(8, non-volatile content 50%) 600 parts was charged, and the temperature was raised to 120 ° C. and melted.

In a dropping funnel, a monomer mixture consisting of 250 parts of ethyl acrylate, 120 parts of 2-hydroxyethyl methacrylate, 300 parts of methyl acrylate, 253 parts of lauryl acrylate and 77 parts of methacrylic acid and Kayaester 0 (Kayaku Akzo Co., Ltd.) 20 parts (made by peroxide polymerization initiator). The monomer mixture and the initiator were added dropwise over 3 hours while maintaining the temperature at 120 ° C. After the dropping, the temperature was further maintained at 120 ° C. for 2 hours. Dimethylethanolamine 80 parts and deionized water 15
By adding 50 parts and dissolving, an opaque and viscous resin dispersion was obtained.

The obtained dispersion had a solid content of 40%, a solid content acid value of 41 and a hydroxyl value of 57. Dilute this with deionized water in a No. 4 Ford cup for 30 seconds, then at 40 ° C for 10 seconds.
The state after standing for a day was visually determined. Uniform dispersion was confirmed immediately after dilution and after the storage stability test.

Production Example 1 Production of Polycarbonate In a glass reaction vessel equipped with a stirrer, a thermometer and a rectification column, 1000 parts (11.1 mol) of dimethyl carbonate and 3-methyl were added.
-1,5-Pentanediol (650 parts) (5.5 mol) and tetraisopropyl titanate (1 part) as a catalyst were added and mixed, and the mixture was heated under normal pressure at 100 ° C for 5 hours and then heated to 200 ° C for 5 hours. The produced methanol was distilled off.

After the distillation of methanol was completed, the reaction was further continued under reduced pressure of 10 mmHg or less for 2 hours. To 500 parts of this reaction product, 99 parts (0.40 mol) of a trimethylolpropane dimer was added and further reacted at 200 ° C. for 4 hours to obtain a polycarbonate having a number average molecular weight of 350 and a hydroxyl value of 154.

Production Example 2 Production of Polysiloxane-Modified Polycarbonate In a glass reaction vessel equipped with a stirrer, thermometer and condenser, 100 parts of the polycarbonate obtained in Production Example 1 and silicone oil "SH3771" (manufactured by Toray Dow Corning Incorporated) , Hydroxyl equivalent 800), and tetraisopropyl titanate 1 part as a catalyst were added and mixed, and the mixture was heated to 200 ° C. and stirred for 3 hours at this temperature to obtain a polysiloxane-modified polycarbonate. The number average molecular weight of the obtained resin is 35.
The hydroxyl value was 00 and the value was 98.

Example 3 A 5-liter Kolben equipped with a stirrer, a nitrogen inlet tube, a temperature control device, a condenser, and a dropping funnel was charged with 300 parts of the polysiloxane-modified polycarbonate obtained in Production Example 2 and 100 parts of xylene. The temperature was raised to ° C.

A dropping funnel was charged with 250 parts of styrene, 150 parts of butyl methacrylate, 250 parts of lauryl methacrylate, 304 parts of 2-ethylhexyl acrylate and 46 parts of methacrylic acid and 30 parts of azobisisobutyronitrile. . The monomer mixture and the initiator were added dropwise over 3 hours while maintaining the temperature at 90 ° C. 2 more at 90 ℃ after dropping
Hold for hours.

48 parts of dimethylethanolamine and 1740 parts of deionized water were added and dissolved to obtain an opaque and viscous resin solution.

The resin solution thus obtained had a solid content of 40% and a solid content acid value of 31.

This product was diluted with deionized water in a No. 4 Ford cup for 30 seconds, and then left standing at 40 ° C. for 10 days, and then visually inspected. Uniform dispersion was confirmed immediately after dilution and after the storage stability test.

Production Example 3 Production of Acrylic Resin A 5-liter Kolben equipped with a stirrer, a nitrogen introducing tube, a temperature control device, a condenser, and a dropping funnel was charged with 400 parts of 2-methoxypropanol and heated to 120 ° C.

In a dropping funnel, 300 parts of styrene, 250 parts of ethyl acrylate, 150 parts of 2-hydroxyethyl methacrylate,
A monomer mixture consisting of 223 parts of 2-ethylhexyl acrylate and 77 parts of methacrylic acid and 30 parts of Kayaester 0 (a peroxide polymerization initiator manufactured by Kayaku Akzo Co., Ltd.) were charged. The monomer mixture and the initiator were added dropwise over 3 hours while maintaining the temperature at 120 ° C. After the dropping, it was further held at 120 ° C. for 2 hours to obtain an acrylic resin. The resulting acrylic resin had a solid content of 71.4, a solid content acid value of 50, and a hydroxyl value of 65.

Comparative Example 1 From 1400 parts of the acrylic resin obtained in Production Example 3, 300 parts of the solvent was distilled off under reduced pressure, 80 parts of dimethylethanolamine and 1740 parts of deionized water were added, and dissolved to give a transparent and viscous product. A resin solution was obtained. When 300 parts of the polysiloxane used in Example 1 was added to this with stirring at a liquid temperature of 80 ° C.,
The polysiloxane formed oily droplets and could not be dispersed.

Example 4 The resin dispersion obtained in Example 1 was diluted with a No. 4 Ford cup for 30 seconds and then coated on an iron plate with a doctor blade to a dry film thickness of 40 microns. , At 110 ℃ 1
Dried for hours. The obtained coating film was evaluated by the following operations.

The good gloss of the coating film means that the transparency and smoothness thereof are good. A large water contact angle of the coating indicates that the coating has excellent water repellency. Further, the NaOH spot test is a simple test of the resistance of the coating film to alkaline water, and the fact that no change in the coating film is observed as a result of this test indicates that the coating film has good chemical resistance and water resistance. Indicates that.

The iron plate coated with the gloss resin was measured at a reflection angle of 20 ° using a digital goniophotometer "UGV-5K" manufactured by Suga Test Instruments Co., Ltd.

Water Contact Angle 0.03 g of pure water was dropped on a resin-coated iron plate to form droplets. The droplet was observed from the horizontal direction of the iron plate, and the angle formed by the droplet cross section with the coated surface was measured.

NaOH Spot Test Five drops of 0.1N NaOH were dropped on a resin-coated iron plate from a dropper, and changes in the coating film after 1 hour were visually observed.

The coating film had a gloss (20 ° gloss) of 153 and a water contact angle of 111 °.

Examples 5 and 6 A coating film was obtained and evaluated in the same manner as in Example 4 except that the resin dispersions obtained in Examples 2 and 3 were used. Table 1 shows the obtained results.

Comparative Example 2 The polysiloxane used in Example 1 was coated on an iron plate with a doctor blade and dried at 110 ° C. for 1 hour to obtain a liquid film having a thickness of 40 μm.

The water contact angle of the obtained liquid film was 122 degrees. The gloss was immeasurable.

Comparative Example 3 The acrylic resin obtained in Production Example 3 was diluted with butyl cellosolve for 30 seconds using a No. 4 Ford cup, and then coated on an iron plate using a bar coater to give a dry film thickness of 40 μm. Then, it was dried at 110 ° C. for 1 hour.

The obtained film has a gloss of 140 and a water contact angle of 80.
Degree.

[0107]

Table 4 Example 4 Example 5 Example 6 Comparative Example 2 Comparative Example 3 Resin Dispersion Example 1 Example 2 Example 3 Polysiloxane Acrylic Resin Gloss 153 151 143-140 Water Contact Angle 111 107 107 122 80 NaOH Spot No change No change No change Melt Melt

[0108]

EFFECTS OF THE INVENTION A water-dispersible resin capable of forming a coating film having excellent transparency, smoothness, chemical resistance, water resistance and water repellency and realizing an aqueous coating material having good coating workability and dispersion stability. Compositions and methods of making the same are provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a multilayer coating film formed using the coating composition of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer coating film, 2 ... Object to be coated, 3 ... Base coating film, 4 ... Clear coating film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 83/10 LRM C08L 83/10 LRM C09D 151/08 PGX C09D 151/08 PGX

Claims (14)

[Claims] 1. (a) 10 to 95% by weight of a polymer or copolymer having a polysiloxy moiety; and (b) (1) 2 to 75% by weight of an ethylenically unsaturated monomer having an acid group and (2) another ethylenic group. A step of radically polymerizing a starting mixture containing 5 to 90% by weight of a monomer mixture containing 25 to 98% by weight of an unsaturated monomer in the presence of a polymerization initiator, and an acid group-containing resin composition obtained by the step Neutralizing the above by adding a neutralizing agent to the water-dispersible resin composition. 2. The method according to claim 1, wherein the polymer or copolymer having a polysiloxy moiety is a polysiloxane having a polysiloxy moiety in the main chain. 3. The method according to claim 1, wherein the polymer or copolymer having a polysiloxy moiety is a polysiloxane-modified resin. 4. The method of claim 3, wherein the polysiloxane modified resin is selected from the group consisting of polysiloxane modified polyester resins, polyether resins, polycarbonate resins, polyurethane resins, epoxy resins and acrylic resins. 5. The method according to claim 1, wherein the radical polymerization is carried out in the presence of an organic solvent. 6. The process according to claim 1, wherein the monomer mixture contains 2 to 50% by weight, based on the monomer mixture, of ethylenically unsaturated monomers having amide groups as other ethylenically unsaturated monomers. 7. The monomer mixture comprises (1) 4-75% by weight of an ethylenically unsaturated monomer having a carboxyl group.
And (2) 25 to 96% by weight of another ethylenically unsaturated monomer. 8. The method according to claim 1, wherein the polymer or copolymer having a polysiloxy moiety has a number average molecular weight of 500 to 20000. 9. The method of claim 2 wherein the polysiloxane has 5 or more consecutive siloxy moieties in the backbone. 10. A water-dispersible resin composition obtained by the method according to claim 1. 11. An aqueous resin dispersion containing the water-dispersible resin composition according to claim 10 and an aqueous medium. 12. An aqueous coating composition containing the aqueous resin dispersion according to claim 11 and a curing agent. 13. The aqueous coating composition according to claim 12, further comprising a pigment. 14. A two-coat / one-bake coating method in which a base paint is applied, and then a clear paint is repeatedly applied without being cured, and the base paint and the clear paint are combined and cured. Item 14. A method which is the aqueous coating composition according to Item 13.