JP3242505B2 - Peelable water-based coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peelable water-based coating composition, and more particularly, to a coating film having excellent water resistance, strength, acid rain resistance, weather resistance and peelability. The present invention also relates to a peelable water-based coating composition having excellent stability during storage and the like.

[0002]

2. Description of the Related Art Conventionally, vehicles such as automobiles, aircraft, machine parts, metal household goods, other ferrous and non-ferrous metal products, wood products, glass products,
Painted plastics products, rubber products, etc.
Or articles such as those that do not require painting,
Frequently, they are transported or temporarily stored indoors or outdoors before they reach the customers. In the period until the article reaches the consumer (usually generally 2 to 12 months or more), dust, iron powder, salts, acids, smoke, insect body fluids and dead bodies, There has been a problem of so-called surface deterioration in which flaws such as birds, sun rays, wind and rain, and other effects cause scratches, stains, discoloration, contamination, and the like on the surface of the article.

[0003] In the case where the above-mentioned surface deterioration occurs, removing the surface deterioration requires labor and expense, and may also reduce the commercial value. In addition, in the industrial zone and its surroundings, soot emitted from factories adheres to articles stored outdoors, and thus the problem of the surface deterioration has been remarkable.

Further, in recent years, when the above-mentioned articles are stored outdoors or the like, acid rain containing contaminants such as sulfur oxides, nitrogen oxides, and hydrochloric acid artificially released due to industrialization may cause the surface of the article to be coated to become acidic. , The acid rain is concentrated and the acidity is further increased, which causes a new problem that the surface deterioration is further promoted. In addition, it is expected that an adverse effect on articles will be more seriously affected by an increase in the amount of ultraviolet rays due to the depletion of the ozone layer, which is advancing recently.

[0005] Therefore, a peelable film is formed on the painted surface or the like with a peelable coating agent made of a resin emulsion or the like which can be peeled after forming the film. Various techniques for protecting the like have been proposed.

However, there has been a problem that the heat resistance, acid rain resistance and weather resistance of the film when stored outdoors are not sufficient with only the resin emulsion and the like that have been conventionally proposed.

In view of the above, a peelable coating agent in which a pigment is added to a resin emulsion to improve the weather resistance of the film has been proposed (Japanese Patent Application Laid-Open No. 56-3255). There is a problem that the stability at the time of storage of the peelable coating agent is deteriorated, and in the above-mentioned peelable coating agent, there is also a case where the stability is improved by adding an acid monomer as a copolymerization component of the resin. Proposals have been made (JP-A-3-275775, JP-A-3-1403).
However, in this case, there is a problem that the releasability of the formed film is reduced.

On the other hand, in recent years, the beautification of the working environment has been progressing, but at present, it is difficult to improve the industrial machine, the painting booth and its surroundings due to severe contamination. In view of the above, there has been proposed a technique for solving the above-mentioned problem by forming a film that can be peeled off by the peelable coating agent on the above-mentioned machinery and its periphery.

[0009] However, with only the resin emulsions and the like that have been conventionally proposed, the peelable film is damaged by the machine oil or the solvent in the paint, and in many cases, peeling is impossible. Further, since a machine or the like dissipates heat during operation, it often deteriorates due to the heat and cannot be peeled off.

[0010] Recently, a filter type filter has been established to prevent contamination of a kitchen ventilation fan or the like, but the filter type is becoming a problem since it becomes large waste after use.

In view of the above, there has been proposed a technique for solving the above-mentioned problem by forming a peelable film with the peelable coating agent on and around the ventilation fan. In the case of a material composed of only a resin emulsion or the like, such as a peelable coating agent, the peelable film is often attacked by heat generated from oil in the smoke, a stove, or the like, and the peelable film cannot be peeled off in many cases.

That is, the conventionally proposed peelable coating material cannot form a coating film excellent in heat resistance, acid rain resistance, solvent resistance, weather resistance and peeling property, and is not sufficiently coated. The protective effect of the surface was not obtained, and the storage stability was not satisfactory.

Accordingly, an object of the present invention is to form a coating film having excellent heat resistance, acid rain resistance, weather resistance, solvent resistance and peelability, and to provide a peelable film having excellent stability during storage and the like. An object of the present invention is to provide a water-based coating composition.

[0014]

As a result of various studies, the present inventors have found that a water-dispersed resin-containing composition capable of forming a cross-linked form during and after film formation can achieve the above object. .

The present invention has been made based on the above findings, and provides a peelable aqueous coating composition comprising the following components (a) and (b) as essential components. (A) a monomer having a reactive functional group selected from a monomer having an acetoacetyl group, a monomer having at least one ald group or keto group and one polymerizable double bond in a molecule; A monomer mixture containing 30% by weight and 90 to 50% by weight of an acrylic acid ester and / or a methacrylic acid ester as essential monomer components, polyvinyl alcohol as a dispersant,
A water-dispersible resin obtained by polymerization using 0.5 to 20 parts by weight of a water-soluble polymer selected from constitutive polysaccharides per 100 parts by weight of the monomer mixture. (B) Monomer 1 having a reactive functional group Crosslinking agent selected from hydrazine derivatives or amines in an amount of 0.1 to 5 mol per mol

Hereinafter, the peelable aqueous coating composition of the present invention will be described in more detail. The peelable aqueous coating composition of the present invention is characterized by containing a specific water-dispersed resin and a specific compounding amount of a crosslinking agent.

The specific water-dispersible resin used as an essential component in the present invention comprises a specific amount of a monomer having a reactive functional group and a specific amount of an acrylic acid ester and / or a methacrylic acid ester. A water-dispersed resin obtained by polymerizing a monomer mixture contained as a monomer component and using a water-soluble polymer as a dispersant in a specific amount.

The viscosity, solid content, p
H and the average particle size are not particularly limited, but the solid content (JIS-K6823) concentration is preferably 1%.
0 to 70% by weight, more preferably 20 to 70% by weight, particularly preferably 30 to 65% by weight, and the viscosity (BH type rotational viscometer 20 rpm, 25 ° C) is preferably 10 to 10000
cps, more preferably 500 to 8000 cps, particularly preferably 500 to 5000 cps, and the pH is preferably 2 to 10, more preferably 3 to 9, and particularly preferably 4 to 9.
9, the average particle diameter is preferably 0.01 to 0.6μ, more preferably 0.02 to 0.5μ, particularly preferably 0.0
A composition having a solid content concentration and a viscosity within the above-mentioned preferred ranges can be used to obtain a high-quality peelable aqueous coating composition of the present invention.

The resin (hereinafter simply referred to as "resin") obtained from the monomer mixture, which forms the water-dispersed resin, has a glass transition temperature (hereinafter abbreviated as Tg) of generally 229 to 303K, more preferably 229 to 303K. 233-283K
By using a water-dispersed resin formed of a resin having a Tg in the above range, it is possible to obtain a peelable aqueous coating composition of the present invention exhibiting excellent peelability and tack throughout winter and summer. Can be. The Tg is:
Based on the calculation formula shown in the following [1]. During _{1 / Tg = W 1 / Tg} 1 + W 2 / Tg 2 + ··· + W n / Tg n ··· [1] equation, Tg, Tgn is displayed in absolute temperature, Wn are each single in the resin It shows the weight fraction of the monomer component. The concentration of the resin component in the solid content of the water-dispersed resin is usually 99 to 90%, preferably 97 to 92%.

[0020]

Examples of the monomer having an acetoacetyl group include alkenyl acetoacetates such as vinyl acetoacetate and allyl acetoacetate: 2-acetoacetoxyethyl acrylate, 2-acetoacetoxyethyl methacrylate, and 2-acetoacetoxypropyl acrylate. (Meth) acrylic acetoacetic acid diesters of alkylene glycols such as, 2-acetoacetoxypropyl methacrylate and 2-cyanoacetoacetoxyethyl methacrylate: crotons of alkylene glycols such as 2-acetoacetoxyethyl crotonate and 2-acetoacetoxypropyl crotonate Acid acetoacetic acid diester; N- (acetoacetoxymethyl) acrylamide;
N- (acetoacetoxymethyl) methacrylamide, N
-(Acetoacetoxyethyl) acrylamide, N-
N- such as (acetoacetoxyethyl) methacrylamide
An acetoacetic ester of alkylol (meth) acrylamide can be mentioned.

Examples of the monomer having at least one ald group or keto group and one polymerizable double bond in the molecule include acrolein, diacetone acrylamide, formylstyrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl Isobutyl ketone, (meth) acryloxyalkylpropanal, diacetone acrylate, acetonyl acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetyl acetate, butanediol-1,4-acrylate-acetyl acetate, etc. Can be mentioned.

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] In the present invention, among the monomers having an upper Symbol least one aldo group or keto group and one polymerizable double bond in the monomer and in the molecule having an acetoacetyl group, especially allyl acetoacetate , 2-acetoacetoxyethyl acrylate, 2-acetoacetoxyethyl methacrylate, 2-acetoacetoxypropyl acrylate, 2-acetoacetoxypropyl methacrylate, diacetone acrylamide, acrolein and vinyl methyl ketone are preferably used.

When using the monomer having a reactive functional group, the above-mentioned compounds can be used alone or in an appropriate mixture.

The above-mentioned specific compounding amount of the monomer having the reactive functional group is set to 0.1% based on the whole monomer mixture.
It is 0.5 to 30% by weight, preferably 1 to 10% by weight.
The amount of the monomer having the reactive functional group is 0.05
If the amount is less than 30% by weight, a sufficient crosslinked structure cannot be obtained, resulting in insufficient heat resistance and acid rain resistance. If the amount exceeds 30% by weight, the coating becomes brittle because the crosslinking density becomes too high. Workability at the time of peeling is deteriorated.

The acrylate used as an essential monomer component in the monomer mixture in the present invention includes cyclohexyl acrylate,
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, i-butyl acrylate, tert-acrylate
Butyl, 2-ethylhexyl acrylate, lauryl acrylate, and the like. Examples of the methacrylate include methyl methacrylate, ethyl methacrylate,
Examples thereof include n-butyl methacrylate, i-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate.

The above-mentioned specific amount of the acrylate and / or methacrylate is 90 to 50% by weight, preferably 80 to 6% by weight, based on the whole monomer mixture.
0% by weight. If the amount is less than 50% by weight, the coating film is too hard and easily broken, resulting in poor workability and poor coating film forming property. When the content exceeds 90% by weight, the adhesion is too strong, the releasability is deteriorated, and the coating film strength becomes insufficient.

In the monomer mixture, acrylonitrile can be preferably used as a monomer component in addition to the essential monomer component. At this time, the amount of the acrylonitrile is preferably 10 to 50% by weight, more preferably 2 to 50% by weight, based on the whole monomer mixture.
0 to 40% by weight. Further, other monomers such as styrene and divinylbenzene may be blended into the monomer mixture, if desired. At this time, the amount of the other monomer is preferably less than 10% by weight.

Examples of the water-soluble polymer used as a dispersant in the water-dispersible resin include polyvinyl alcohol and polysaccharides. Examples of the high molecular polysaccharide include hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose and the like. The molecular weight of the high molecular polysaccharide is preferably 10,000 or more. The polyvinyl alcohol is preferably partially saponified, more preferably a saponification degree of 85 to 99%, and a polymerization degree of 300 to 3000. The polyvinyl alcohol was manufactured by Kuraray Co., Ltd., "PVA-
205 "," PVA-217 "and the like can also be used as commercial products.

The water-soluble polymer is an anionized polyvinyl alcohol, particularly a saponification degree of 80 to 99%.
Anionic polyvinyl alcohol is preferred. Specifically, for example, an alkali olefin sulfonate and vinyl acetate are copolymerized in the presence of an alcohol solvent so that the content of the alkali olefin sulfonate is 0.5 to 7 mol%. Modified polyvinyl alcohol obtained by saponifying a polymerized copolymer is exemplified. As a commercially available product, "Gohselan L-3266" [86 to 89% of saponification degree, polymerization degree of 25
0 to 300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.].

The specific amount of the water-soluble polymer is 0.5 to 0.5 parts by weight of the monomer mixture.
To 20 parts by weight, preferably 0.5 to 5 parts by weight. When the amount of the water-soluble polymer used is 0.5 to 20 parts by weight, the resulting water-dispersed resin has excellent stability, and the formed film has excellent film strength and water resistance. When the amount is less than 10 parts by weight, the stability of the resulting water-dispersed resin is poor, gelation occurs during the reaction, or undesired phase separation easily occurs during storage of the release coating composition of the present invention. If it exceeds, the water resistance of the formed film decreases.

The above water-dispersible resin is preferably prepared by an emulsion polymerization method. In the emulsion polymerization method, a surfactant and the above-mentioned water-soluble resin are prepared in an aqueous medium in the presence of a catalyst according to a known method. It is performed under the coexistence condition of the molecule.

Examples of the surfactant used in the emulsion polymerization method include anionic surfactants such as sodium olefinate, semi-hardened tallow soda, and fatty acid salts such as potassium oleate, lauryl sulfate soda, and higher alcohols. Higher alcohol sulfates such as sodium sulfate sulfate, lauryl alcohol sulfate triethanolamine salt, ammonium lauryl alcohol sulfate ester, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, and alkyl naphthalene sulfonates such as sodium alkyl naphthalene sulfonate salt,
Dialkyl sulfo amber salts such as naphthalene sulfonate formalin condensate, dioctyl sulfo sodium succinate,
Examples thereof include alkyl phosphates and those obtained by adding ethylene oxide to the above anionic surfactants. These may be used alone or in combination of two or more.

The anionic surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether, polyoxyethylene nonyl phenyl ether, and polyoxyethylene nonyl phenyl ether. Polyoxyethylene alkyl phenyl ether such as ethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene alkyl ester such as polyoxyethylene monostearate, sorbitan monolaurate, sorbitan ester such as sorbitan monostearate, polyoxy Polyoxyethylene sorbitan alkyl ester such as ethylene sorbitan monolaurate, polyoxyethylene polypropylene block polymer, polyethylene glycol It can also be used in combination and the like. Furthermore,
Amphoteric surfactants, such as dimethylalkyl betaine,
Betaine-type amphoteric surfactants such as lauryl betaine and stearyl betaine, and a small amount of a cationic surfactant can also be used in combination.

Examples of the catalyst used in the emulsion polymerization method include persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, hydrogen peroxide, tertiary butyl hydroperoxide, cumene hydroperoxide and the like. And the like, preferably persulfate and hydrogen peroxide.

In the emulsion polymerization method, a reducing agent can be used in combination, if desired. Examples thereof include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, and glucose, sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite.

The reaction temperature in the above emulsion polymerization method can be appropriately selected, and for example, a temperature of about 40 to about 90 ° C. can be exemplified. At the time of the reaction, the entire amount of the predetermined surfactant can be added to the reaction system, but a part of the surfactant is added to the reaction system in advance to start the reaction, and the remainder is added continuously or at intervals during the reaction. It can be added in portions, the latter being preferred. Also, for each monomer, it can be added as it is, batch addition, split addition, or continuous addition,
It is preferable to add continuously from the viewpoint of reaction control.

In the emulsion polymerization, a pH regulator, a polymerization degree regulator, an antifoaming agent and the like can be appropriately added during the emulsion polymerization, in addition to the above-mentioned surfactant and catalyst.

[0045] In the present invention, as the crosslinking agent used as an essential component, hydrazine derivatives, amines and the like.

The hydrazine derivative has 2 carbon atoms.
10 to 10 water-soluble dicarboxylic acid dihydrazides, for example,
Isohydric acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, etc .; Hydrazine, for example, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine and the like can be mentioned.

Examples of the amines include amines having two or more amino groups, such as aliphatic polyamines having 2 to 10 carbon atoms and aromatic polyamines having 6 to 16 carbon atoms. As the aliphatic polyamines, for example, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethinediamine,
Hexamethylenediamine, 1,7-diaminoheptane,
1,8-diaminooctane, 1,9-diaminononane,
Examples thereof include 1,10-diaminodecane and triaminopropane, and the aromatic polyamines include, for example, o
-Phenylenediamine, m-phenylenediamine, p-
Examples include phenylenediamine, triaminobenzene, triaminophenol and the like.

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] In the present invention, especially, Jihidorashido adipic acid, Jihidorashido isophthalic acid, Jihidorashido succinic acid, ethylenediamine, can be preferably used trimethylene diamine.

When using the above-mentioned cross-linking agent, the above-mentioned compounds can be used alone or in an appropriate mixture.

The specific compounding amount of the crosslinking agent is 0.1 to 5 mol, preferably 0.2 to 5 mol, per 1 mol of the monomer having a reactive functional group in the aqueous dispersion resin.
3 moles. When the amount of the crosslinking agent is less than 0.1 mol, a sufficient crosslinked structure cannot be obtained, heat resistance and acid rain resistance become insufficient, and when the amount exceeds 5 mol, the crosslink density becomes insufficient. Since the film is too high, the film becomes brittle and the workability at the time of peeling is deteriorated.

In the peelable water-based coating composition of the present invention, it is preferable to appropriately mix a pigment, an ultraviolet absorber and a water repellent in addition to the water-dispersible resin and the crosslinking agent.

Examples of the pigment include titanium oxide,
Organic or inorganic coloring pigments such as carbon black, red iron oxide, high the yellow, benzidine yellow, phthalocyanine blue, and quinacridone red; calcium carbonate, silica, alumina, kaolin, clay, talc, diatomaceous earth,
Preferred are extenders such as mica, aluminum hydroxide, glass powder, barium sulfate, and magnesium carbonate. When used, they can be used alone or as a mixture.

The amount of the pigment is preferably 25 to 400 parts by weight, more preferably 40 to 150 parts by weight, based on 100 parts by weight of the monomer mixture. By using the above-mentioned pigment in the above-mentioned compounding amount, it is possible to increase the shielding property against ultraviolet rays, to improve the peelability after being stored outdoors, and to increase the strength of the coating film and to improve the water resistance of the coating film. .

Examples of the ultraviolet absorber include phenyl salicylate, p-octylphenyl salicylate, 4-t-butylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2,2'- Dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-
4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, sodium 2 , 2'-dihydroxy-4,
4'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4-oxybenzylbenzophenone, 2,
2'-4,4'-tetrahydroxybenzophenone, 2
-Hydroxy-4-dodecyloxybenzophenone, 5-
Chloro-2-hydroxybenzophenone, 2-hydroxy-4-methoxy-4′-chlorobenzophenone, 2,
2'-dihydroxy-4-octoxybenzophenone,
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-3'5'-di- t-butylphenyl) -5-
Chlorobenzotriazole, 2- (2'-hydroxy-
3'5'-di-t-amylphenyl) -2-hydroxybenzotriazole, nickel-bis-octylphenyl sulfide, [2,2'-thio-bis- (4-t-
Octylphenolate)]-n-butylamine nickel, nickel dibutyldithiocarbamate and the like, and when used, they can be used alone or as a mixture.

The amount of the ultraviolet absorber is preferably 0.01 to 100 parts by weight of the monomer mixture.
It is 10 parts by weight, more preferably 0.1 to 5 parts by weight.
By using the above-mentioned ultraviolet absorber in the above-mentioned compounding amount,
The ultraviolet ray shielding effect can be enhanced, and the peeling property after being stored outdoors can be improved.

The water repellent is preferably a wax, a silicon compound, a fluorine compound, or the like.

Examples of the wax include vegetable waxes such as candelilla wax, carnauba wax, rice wax, wood wax and jojoba oil; animal waxes such as beeswax, lanolin and whale wax; minerals such as montan wax, ozokerite and ceresin Petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam; synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene oxide wax, polyethylene wax, acryl-ethylene copolymer wax; montan wax derivatives, paraffin Modified waxes such as wax derivatives and microcrystalline wax derivatives; hydrogenated waxes such as hardened castor oil and hardened castor oil derivatives; 12-hydroxystearic acid;
Stearic acid amide; phthalic anhydride; bisamide, amide; glycerin ester; sorbitan ester; higher alcohol; The wax preferably has a melting point of about 15 to 250 ° C, more preferably about 20 to 180 ° C.

Examples of the silicon-based compound include a dimethylpolysiloxane-based compound, a methylphenylpolysiloxane-based compound,
Preferred are cyclic dimethylpolysiloxane-based, chloropolysiloxane-based, modified (amino, epoxy, polyether, alcohol, fluorine, mercapto, carboxy, alkyl) higher fatty acids and the like, and specifically, commercially available products as described below. And the like.

"SH203", "BY16-828",
“SF8411”, “SF8418”, “BY16-8”
38 "," SF8422 "," BY16-848 ",
“SH3771”, “SH3746”, “SF841”
9 ", silicone oil such as" FS1265 ";" R90
0 "," R901 "," R902 "," F100 ",
“F101”, “F200”, “F201”, “F20”
2 "," F203 "," F400 "," F300 ",
“F301”, “F250”, “E500”, “E50”
1 "," E600 "," E601 "," E602 ",
Silicon powders such as "E603" and "E850";"SH
Aqueous resins such as "3746", "SH3749", "SH3771";"SH204","SH490","SH7"
024 "," SH7028 "," SH7036 "," S
Silicon emulsions such as "H7060";
Trade name, manufactured by Toray Silicone Co., Ltd.] Silicon beads such as "Tospearl 105", "Tospearl 108", and "Tospearl 120"; [all of the above are trade names, manufactured by Toshiba Silicon Corporation]

The fluorine-based compound includes a fluoroalkyl group-containing molecule having a molecular weight of about 1,000 to 200.
00 are preferred, and specifically, perfluoroalkyl carboxylate, perfluoroalkyl phosphate,
Perfluoroalkyltrimethylammonium salts, perfluoroalkylbetatanone, perfluoroalkylEO adducts and the like can be mentioned. Further, as the fluorine compound,
"Surflon S-111", "Surflon S-11"
2, Surflon S-113, Surflon S-1
21, "Surflon S-131", "Surflon S-131"
132 "," Surflon S-142 "," Surflon S
-145 "," Surflon 131S "," Surflon 1
45S "(all of which are trade names, manufactured by Asahi Glass Co., Ltd.), etc.
"Polyfluor 400", "Polyblend 100XF"
Commercial products such as [all of the above are trade names, manufactured by MPI Corporation] can also be used.

As the water repellent, any of the waxes, silicon compounds and fluorine compounds specifically exemplified above may be used alone or as a mixture.

The compounding amount of the water repellent is preferably 0.01 to 30 parts by weight based on 100 parts by weight of the monomer mixture. In particular, when the wax is used as the water repellent, it is preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight, and when the silicon compound is used as the water repellent, When the above-mentioned fluorine compound is used, it is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 20 parts by weight. By using the above water-repellent in the above-mentioned amount, the water-repellent effect can be enhanced, and the water resistance and acid rain resistance can be improved.

In the peelable water-based coating composition of the present invention, if necessary, a film-forming auxiliary, a plasticizer, a defoaming agent, a pH adjuster, and the like, as long as the desired effects of the present invention are not impaired.
Other additives such as a preservative, a fungicide, a thickener, and an antifreezing agent can be appropriately added.

Examples of the film-forming auxiliary include methyl cellosolve, ethyl cellosolve, butyl cellosolve,
Methyl carbitol, ethyl carbitol, butyl carbitol, dibutyl carbitol, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, benzyl alcohol, benzyl acetate, toluene, Xylene, petroleum hydrocarbons, texanol and the like. Among them, butyl carbitol, butyl cellosolve acetate, butyl carbitol acetate,
Texanol or the like is preferable, and when the peelable aqueous coating composition of the present invention forms a film, it has an effect of lowering the film formation temperature, and its use amount is generally about 0.5 to 100 parts by weight of the water-dispersed resin. 15 parts by weight, preferably about 1 to 8 parts by weight.

Examples of the antifoaming agent include silica silicone, silicone, metal soap, fatty acid amide, fatty acid ester, polyether, polyglycol, organic phosphoric acid, higher alcohol, sulfonated Fatty acids, oil-soluble polymers and the like can be mentioned. Among them, especially silicone type, silica silicone type, metal soap type,
Fatty acid amides, or composites thereof are preferred,
When the peelable water-based coating composition of the present invention is transported, subdivided, and exerts an antifoaming effect at the time of application, the amount of use is generally 0.000 parts by weight per 100 parts by weight of the water-dispersed resin.
1 to 1 part by weight.

The form of the peelable aqueous coating composition of the present invention is not particularly limited as long as the water-dispersible resin and the cross-linking agent are essential components. Composition consisting of a mixture of
A "one-pack type") or a composition comprising at least the above-mentioned agent I containing the water-dispersible resin and the above-mentioned agent II containing at least the crosslinking agent (hereinafter referred to as "two-pack type"). preferable.

To prepare the one-pack type, the water-dispersed resin and the crosslinking agent are mixed, and if necessary, the pigment, the ultraviolet absorber, the water repellent and the other additives are added. It can be easily obtained by adding and mixing. At this time, when the cross-linking agent is a solid, it may be added to the water-dispersed resin and mixed as it is, but it is preferable that the cross-linking agent is preliminarily dispersed in water and then mixed. In the case of (1), it may be added as it is to the water-dispersed resin and mixed, but it is preferable to add and mix after dilution with water in advance.

To prepare the two-liquid type, the water-dispersible resin and the crosslinking agent, one or both of them, preferably the water-dispersible resin, and if necessary, the pigment and the ultraviolet light It can be easily obtained by adding and mixing the absorbent, the water repellent, and the other additives to prepare the agent I containing the water-dispersed resin and the agent II containing the crosslinking agent. At this time, the crosslinking agent may be used as it is, but in the case of a solid, an aqueous dispersion dispersed in water,
In the case of a liquid, it is preferable to use it as an aqueous solution diluted with water.

Further, the peelable water-based coating composition of the present invention can be used for vehicles such as automobiles, aircraft, machine parts, metal household products, other ferrous and non-ferrous metal products, wood products, glass products,
Painted plastics products, rubber products, etc.
Alternatively, it can be preferably used as it is, which does not require painting.

[0076]

EXAMPLES Hereinafter, the strippable water-based coating composition of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Production Example 1] In a 2 liter glass flask equipped with a stirrer, 413 g of water and 18 g of polyvinyl alcohol [“PVA-205” manufactured by Kuraray Co., Ltd.] were added and dissolved to obtain an aqueous solution of polyvinyl alcohol. . On the other hand, polyoxyethylene noniphenyl ether (approximately 30 moles of ethylene oxide added) was added to 130 g of water.
g and 3 g of sodium dodecylbenzenesulfonate were added to an aqueous surfactant solution obtained by dissolving 3 g of sodium dodecylbenzenesulfonate.
g, 204 g of acrylonitrile and 36 g of acetoacetoxyethyl methacrylate were added and mixed by stirring to obtain a monomer composition. Next, after the inside of the flask was replaced with nitrogen, the monomer composition 7 was added to the aqueous solution in the flask while maintaining the reaction temperature at 70 ° C.
53 g, 50 g of 4% ammonium persulfate aqueous solution and 4%
Emulsion polymerization was carried out by adding 50 g of sodium metabisulfite over 5 hours. Thereafter, a small amount of ammonia was added, and the pH was 7.4, the solid content was about 50%, and the viscosity was about 1500 c.
A ps water-dispersed resin was obtained.

Production Example 2 400 g of water and 5 g of polyvinyl alcohol ["PVA-217" manufactured by Kuraray Co., Ltd.] were added to a 2 liter glass flask equipped with a stirrer and dissolved to obtain an aqueous solution of polyvinyl alcohol. . On the other hand, polyoxyethylene noniphenyl ether (approximately 30 moles of ethylene oxide added) was added to 130 g of water.
g, 3 g of sodium dodecylbenzenesulfonate and 24 g of diacetone acrylamide as a monomer component, and 372 g of butyl acrylate and acrylonitrile 204 as a monomer component.
g was added and stirred and mixed to obtain a monomer composition containing the monomer mixture. Then, after the inside of the flask was replaced with nitrogen, while maintaining the reaction temperature at 70 ° C., 753 g of the monomer composition, 50 g of a 4% ammonium persulfate aqueous solution, and 50 g of a 4% sodium metabisulfite solution were added to the aqueous solution in the flask. Was added over 5 hours to carry out emulsion polymerization.
Thereafter, a small amount of ammonia was added to obtain an aqueous dispersion resin having a pH of 7.3, a solid content of about 50%, and a viscosity of about 1000 cps.

[Examples 1 to 5] The water-dispersed resin, crosslinking agent, pigment, ultraviolet absorber and water repellent shown in [Table 1] were used as shown in [Table 1].
The peelable aqueous coating composition was obtained by blending in the amounts shown in Table 1. The resulting peelable aqueous coating composition was tested for heat resistance, hot water resistance, weather resistance, and acid rain resistance.
The results are shown in [Table 1].

[Production Example 3] 413 g of water and 18 g of Poval (“PVA-205” manufactured by Kuraray Co., Ltd.) were added and dissolved in a 2 liter glass flask equipped with a stirrer.
An aqueous solution of polyvinyl alcohol was obtained. On the other hand, water 130
To a surfactant solution obtained by dissolving 20 g of polyoxyethylene noniphenyl ether (approximately 30 moles of ethylene oxide added) and 3 g of sodium dodecylbenzenesulfonate, 420 g of butyl acrylate and 180 g of acrylonitrile were added, followed by stirring and mixing. Thus, a monomer composition was obtained. Next, after the inside of the flask was replaced with nitrogen, while maintaining the reaction temperature at 70 ° C, the aqueous solution in the flask was
753 g of the above monomer composition, 50 g of a 4% ammonium persulfate aqueous solution and 50 g of 4% sodium metabisulfite
The emulsion polymerization was carried out by adding over time. Thereafter, a small amount of ammonia was added, and the pH was 7.2 and the solid content was about 50.
%, A water-dispersed resin having a viscosity of about 1400 cps was obtained.

Production Example 4 400 g of water and 5 g of polyvinyl alcohol ["PVA-217" manufactured by Kuraray Co., Ltd.] were added and dissolved in a 2 liter glass flask equipped with a stirrer to obtain an aqueous solution of polyvinyl alcohol. . On the other hand, polyoxyethylene nonyl phenyl ether (approximately 30 moles of ethylene oxide added) was added to 130 g of water.
0 g and 3 g of sodium dodecylbenzenesulfonate were added to an aqueous solution of a surfactant obtained by dissolving 3 g of sodium dodecylbenzenesulfonate.
A monomer mixture consisting of 0 g, 180 g of acrylonitrile and 30 g of divinylbenzene was added, and mixed by stirring to obtain a monomer composition. Then, after the inside of the flask was replaced with nitrogen, while maintaining the reaction temperature at 70 ° C., 753 g of the monomer composition, 50 g of a 4% ammonium persulfate aqueous solution, and 50 g of a 4% sodium metabisulfite solution were added to the aqueous solution in the flask. Was added over 5 hours to carry out emulsion polymerization. Thereafter, a small amount of ammonia was added, and the pH was adjusted to 7.0.
5. A water-dispersed resin having a solid content of about 50% and a viscosity of about 1100 cps was obtained.

[Comparative Examples 1 to 4 ] A water-dispersible resin, a pigment, an ultraviolet absorber and a water repellent shown in [Table 1] were blended in the amounts shown in [Table 1], and a peelable aqueous coating composition was prepared. Obtained. The obtained peelable aqueous coating composition was tested for heat resistance, water resistance, weather resistance, and acid rain resistance. The results are shown in [Table 1].

[0083]

[Table 1]

* In the table is as follows. * 1 Amount: solids by weight. * 2 Biosorb 130: trade name, manufactured by Kyodo Yakuhin Co., Ltd. Powder, 2-hydroxy-4-octoxybenzophenone. * 3 Biosorb 520: manufactured by Kyodo Yakuhin Co., Ltd., trade name. Powder, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole. * 4 Biosorb 582: manufactured by Kyodo Yakuhin Co., Ltd., trade name. Powder, 2- (2'-hydroxy-3 ', 5'-di-t-
(Butylphenyl) benzotriazole. * 5 Chemipearl W-300: Mitsui Petrochemical Industry Co., Ltd.
Made, trade name. Aqueous dispersion low molecular weight polyolefin particle size 3
μ, melting point 115 ° C. * 6 Tospearl 120: manufactured by Toshiba Silicone Co., Ltd., trade name, powder, silicone resin, particle diameter 2 μm. * 7 Polyfluor 400: manufactured by MPI Corporation, trade name, powder, fluororesin, particle diameter 3μ. * 8 Acid rain resistance

Each of the above tests was carried out as follows using a test plate prepared as follows. [Production of test plate] First, an aminoalkyd resin yarn paint (manufactured by Kansai Paint Co., Ltd., trade name: “Amirac”) was applied to a mild steel plate (0.8 mm thick) surface-treated with “Valbond 3060” at 140 ° C. for 20 minutes. The coated composition obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was applied using an applicator so as to have a dry film thickness of 100 μm, and dried at 20 ° C. for 24 hours. By doing this, a test plate having a coating formed on the coated surface was obtained.

Heat resistance: The test plate was allowed to stand at 120 ° C. for 5 hours, then at 20 ° C. for 1 hour,
At 1 ° C, the film on the test plate was 1 inch wide and 20
Peel at a speed of mm / min and peel strength (kg / inc
h) was measured. In addition, the occurrence of stains, a change in color, and a change in gloss (appearance of the coated surface) on the coated surface of the coated object after peeling the coating were evaluated according to the following evaluation criteria. [Evaluation criteria] ・ ・ ・: good as before Δ: slight change is observed. X: A remarkable change is observed.

Warm water resistance: After immersing the test plate in water at a temperature of 60 ° C. for 240 hours, the test plate was taken out, and it was evaluated whether or not the film was spontaneously peeled or partially peeled according to the following evaluation criteria. (Peelability). Thereafter, the film was peeled off, and the occurrence of spots, a change in color, and a change in gloss (appearance of the coated surface) on the coated surface of the coated object were evaluated according to the following evaluation criteria. [Evaluation criteria for peelability] 性 の: good as before Δ: Partial peeling is observed. ×: spontaneous peeling has occurred. [Evaluation Criteria for Appearance of Coated Surface] ・ ・ ・: Good as before. Δ: slight change is observed. X: A remarkable change is observed.

Weathering resistance: An accelerated weathering test was performed using “Sunshine Weather Meter” manufactured by Suga Test Instruments Co., Ltd. Test conditions: Black panel temperature: 63 ° C. Rainfall time: 18 minutes during 2 hours Ultraviolet irradiation: 400 hours Peelability [peel strength (kg / inch)] to evaluate the appearance of the coated surface.

Acid Rain Resistance The test plate is placed horizontally, and the test solution prepared by the following <Composition> and <Adjustment method> is spotted (the spot amount of the test solution is 0.5 ml). Thereafter, the composition was dried in an oven set at 85 ° C. for 30 minutes, the peelable composition was peeled off, and the occurrence of spots, a change in color, and a change in gloss on the coated surface of the object were observed according to the following evaluation criteria.

<Composition> (Anion liquid) The following 1) to 3) were mixed, and ion-exchanged water was further added thereto to make the whole 1000 g to obtain an anion liquid. 1) sulfate _{(JISK8951) H 2 SO 4 (} 98%) 102.0g 2) hydrochloric acid (JISK8180) HCl (35%) 200.0g 3) nitrate _{(JISK8541) HNO 3 (70%} ) 42.9g ( cationic liquid) below 4) To 7) were mixed, and ion-exchanged water was further added thereto to make the whole 1000 g to obtain an anion liquid. 4) Ammonia water (JISK8085) NH ₃ (28%) 35.7g 5) Calcium hydroxide (JISK8575) Ca (OH) (95%) 10.5g 6) Sodium hydroxide (JISK8576) NaOH (95%) 12.6g 7) Potassium hydroxide (JISK8574) KOH (85%) 1.2g The percentages in parentheses indicate the purity (content) of each reagent.
The JIS numbers are for reference only. <Adjustment method> The anion solution was added to the cation solution until pH = 1, and stirring was continued for 24 hours. After 24 hours,
= 1 and this is used as the test solution.

[Evaluation Criteria] Good: The appearance of the painted surface is good as before. ×: The coating surface was damaged by the test liquid, and blistering, whitening, gloss, etc. occurred.

[0092]

The strippable water-based coating composition of the present invention can form a coating film having excellent water resistance, strength, acid rain resistance, weather resistance and peelability, and has good stability during storage and the like. It is excellent.

Continuation of the front page (56) References JP-A-60-96671 (JP, A) JP-A-61-78883 (JP, A) JP-A-5-179102 (JP, A) JP-A-62-25367 (JP) , A) JP-B-63-55548 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 5/20

Claims (6)

(57) [Claims] 1. A strippable water-based coating composition comprising the following components (a) and (b) as essential components. (A) a monomer having a reactive functional group selected from a monomer having an acetoacetyl group, a monomer having at least one ald group or keto group and one polymerizable double bond in a molecule; A monomer mixture containing 30% by weight and 90 to 50% by weight of an acrylic acid ester and / or a methacrylic acid ester as essential monomer components, polyvinyl alcohol as a dispersant,
A water-dispersible resin obtained by polymerization using 0.5 to 20 parts by weight of a water-soluble polymer selected from constitutive polysaccharides per 100 parts by weight of the monomer mixture. (B) Monomer 1 having a reactive functional group Crosslinking agent selected from hydrazine derivatives or amines in an amount of 0.1 to 5 mol per mol 2. The peelable aqueous coating composition according to claim 1, comprising a mixture of the above (a) and (b). 3. The peelable aqueous coating composition according to claim 1, comprising an agent I containing at least the above (a) and an agent II containing at least the above (b). 4. The peelable aqueous coating composition according to claim 1, wherein the water-soluble polymer is an anionic polyvinyl alcohol. 5. The strippable aqueous coating composition according to claim 1, wherein the monomer mixture (a) further contains acrylonitrile as a monomer component. 6. The peelable water-based coating composition according to claim 1, further comprising a pigment, an ultraviolet absorber, and a water repellent.