JP2001181558A - Aqueous temporary protective coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous temporary protective coating composition which forms a protective coated film which has an adhesivity at low temperatures, may be released at a wide range of temperature and has a coated film strength allowing no break when released. SOLUTION: The aqueous temporary protective coating composition comprises a copolymer emulsion obtained by reacting a monomer mixture comprising, against 100 pts.wt. total monomer mixture, from 1 to 60 pts.wt. conjugate diene monomer (1) and from 40 to 99 pts.wt. polymerizable monomer (2) which is copolymerizable with monomer (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for the purpose of temporarily protecting an external coating film of an automobile or the like. More specifically, if the adhesiveness to the protected surface is high even at a low temperature such as 0 ° C.
The present invention relates to a water-based temporary protective coating composition which forms a temporary protective coating having a wide usable temperature range and an excellent balance of contradictory performances in that it can be easily peeled even at a high temperature such as at least ℃.

[0002]

2. Description of the Related Art From metal products such as automobiles, railcars, aircraft, ships and various mechanical parts, to woodwork products such as furniture, plastic products, glass products, and the like, from products to the hands of consumers from factories. For the temporary protection of the transportation and storage period, such as sand, dust, iron powder, acid rain, bird droppings, salt, sunlight, etc. Various methods have been proposed for the purpose of preventing contamination. First of all, a method of applying an aliphatic hydrocarbon-based organic solvent dispersion of a wax to the surface of the material to be protected is mentioned. Waste liquid treatment is a problem from the standpoint of environmental protection. Therefore, there is a strong demand for a protective film that does not require the use of a release agent or the like and that can be peeled off as a continuous film. The peelable protective film is roughly classified into a water-based temporary protective paint that forms a coating film by spraying, roll coating, etc., a so-called strippable paint, and a film obtained by applying an adhesive to a film such as an olefin-based film. No. The latter can cope with a simple shape to some extent, but it is difficult to cope with a complicated shape or a size outside the fixed form. Under such circumstances, attention has been focused on the former, that is, an aqueous temporary protective coating that does not contain an organic solvent or the like and can also respond to a complex shape or a size other than a fixed size, and various methods have been proposed. , All have some challenges.

[0003] Japanese Patent Publication No. 44-29593 proposes an aqueous temporary protective coating having excellent coating film strength and comprising an emulsion of a copolymer obtained by copolymerizing an acrylic monomer containing acrylonitrile as an essential monomer. However, this has a problem that harmful cyan gas is generated when incinerating and disposing of a coating film that becomes unnecessary after peeling. Japanese Patent Application Laid-Open No. 9-192593 discloses a glass transition temperature (hereinafter referred to as Tg).
There is that. ) At 5 to 30 ° C. are proposed. This water-based temporary protective coating does not contain acrylonitrile and does not cause the above-described problems, but at temperatures higher than Tg, the coating strength is weak, so that the peelability is poor. Has a disadvantage that the adhesion of the film deteriorates and the coating film is easily peeled off when the product is left at a low temperature. To solve such a problem, Japanese Patent Application Laid-Open No. 9-28693 has been proposed.
In No. 4, acrylic emulsion with Tg of 40 ° C. or more and Tg
It has been proposed to balance adhesion, particularly low-temperature adhesion, and releasability, especially high-temperature releasability, by using an acrylic emulsion at 5 to -20C. Although the adhesiveness and the releasability have reached a practical level for the time being compared with those before that, further improvement in performance is required. That is, -20 to 7
In applications that are used in a wide temperature range such as 0 ° C., a property of stably adhering in that temperature range and being easily peelable is required, but has not yet reached a satisfactory level. . There is also room for improvement in that a complicated process of mixing two types of emulsions is required. In JP-A-9-241541, the elongation is 100% or more and the tensile strength is 100 kg /
Although a peelable aqueous coating composition comprising an emulsion containing a rubber or a derivative thereof having a cm ² is proposed,
There is room for improvement in that a complicated process of dispersing a rubber or a derivative thereof once in a powder form in water and then mixing the resultant with an acrylic emulsion is required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to form a protective coating film which maintains adhesion at a low temperature, can be easily peeled over a wide temperature range, and has a film strength which does not break at the time of peeling. To provide a water-based temporary protective coating composition.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, the total monomer mixture 1
A monomer comprising a polymerizable monomer (2) copolymerizable with 1 to 60 parts by weight of the conjugated diene monomer (1) and 40 to 99 parts by weight of (1) in 00 parts by weight. The present inventors have found that an aqueous temporary protective coating composition comprising an emulsion of a copolymer obtained by reacting a mixture solves all of the above problems, and have completed the present invention. That is, the present invention relates to (1) a polymerizable monomer copolymerizable with 1 to 60 parts by weight of the conjugated diene monomer (1) and 40 to 99 parts by weight of (1) in 100 parts by weight of the total monomer mixture. Aqueous temporary protective coating composition comprising a copolymer emulsion obtained by reacting a monomer mixture comprising the monomer (2), (2) and 0.1% by weight per 100 parts by weight of the total monomer mixture. The aqueous temporary protective coating composition according to the above (1), comprising from 1 to 5 parts by weight of a weathering stabilizer, wherein the polymerizable monomer (2) copolymerizable with (3) (1) has 1 to 1 carbon atoms. The water-based temporary protective coating composition according to the above (1), which comprises 20 alkyl (meth) acrylates or an aromatic vinyl compound;
To 20 to 9 parts by weight of alkyl (meth) acrylate or aromatic vinyl compound in 100 parts by weight of the total monomer mixture.
The aqueous temporary protective coating composition according to the above (3), which comprises 8.9 parts by weight, (5) a polymerizable monomer (2) copolymerizable with (1), wherein at least one carboxyl group per molecule; A monomer having a hydroxyl group or a sulfonic acid (salt) group is added in an amount of 0.1 to 10 parts by weight in 100 parts by weight of the total monomer mixture.
The aqueous temporary protective coating composition according to the above (1), which contains parts by weight.
(6) The above (2), wherein the weathering stabilizer is a phenolic antioxidant, a phosphite antioxidant, a thioether antioxidant, a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber or a hindered amine light stabilizer. (7) The aqueous temporary protective coating composition according to (1), wherein the conjugated diene-based monomer (1) is 1,3-butadiene, (8) a carbon number of 1
-20 alkyl (meth) acrylates are methyl methacrylate, ethyl acrylate, butyl acrylate,
The aqueous temporary protective coating composition according to the above (3), which is 2-ethylhexyl acrylate or isononyl acrylate, and the aromatic vinyl compound is styrene; (9) The aqueous temporary protective coating composition for temporary protection of a painted outer plate or an exterior part of an automobile. (1) The aqueous temporary protective coating composition according to any one of (1) to (8), and (10) the aqueous temporary protective coating composition according to any of (1) to (8) above on the surface of the material to be protected. Coating,
A temporary protective film obtained by drying.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer emulsion used in the present invention is a conventionally known emulsion polymerization method, that is,
For example, a monomer mixture comprising a conjugated diene monomer (1), a polymerizable monomer (2) copolymerizable with (1) in an aqueous medium such as water, a polymerization initiator, an interface It can be obtained by appropriately adding an activator, a polymerization chain transfer agent and the like and conducting emulsion polymerization. The method of adding the monomer component is not particularly limited, and an arbitrary method such as a batch addition method, a continuous addition method, or a multi-stage addition method is employed. The structure of the particles obtained by the emulsion polymerization method is not particularly limited, a single-phase structure, the structure of the present invention can be solved by any structure such as a multi-phase structure, but when a multi-phase structure is taken A core / shell structure is preferred. The conjugated diene monomer (1) used in the present invention includes, for example, 1,3-butadiene, isoprene, 2-chloro-1,3
-Butadiene, 2-methyl-1,3-butadiene and the like. These conjugated diene monomers (1)
Are used alone or in combination of two or more.
In the present invention, 1,3-butadiene is particularly preferably used.

The amount of the conjugated diene monomer (1) used is 1 to 60 parts by weight, preferably 5 to 50 parts by weight, more preferably 15 parts by weight, based on 100 parts by weight of the total monomer mixture.
４５45 parts by weight. If the amount used is less than 1 part by weight, the adhesion at low temperatures is insufficient, and the coating film is easily peeled off by wind or the like, or even if the adhesion is sufficiently obtained, the film is peeled at a temperature lower than Tg. In some cases, the coating film is broken in the middle of the peeling. On the other hand, when the coating film is peeled at a high temperature, the coating film may be broken. When the use amount of (1) exceeds 60 parts by weight, the adhesion to the material to be protected becomes too high compared to the increase in the strength of the coating film, so that the film cannot be peeled off. The polymerizable monomer (2) copolymerizable with (1) used in the present invention may be any monomer having radical polymerizability, and examples thereof include the following. Can be. (A) Alkyl (meth) acrylate monomers As members of this group, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-
Ethylhexyl (meth) acrylate, isononyl (meth) acrylate, stearyl (meth) acrylate,
Alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group, such as lauroyl (meth) acrylate, can be mentioned. Preferred are alkyl (meth) acrylates having 1 to 9 carbon atoms, and more preferred. Is methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, and most preferred are methyl methacrylate, ethyl acrylate, and butyl acrylate. (B) Aromatic vinyl compound, aromatic vinylidene compound As a member belonging to this group, for example, styrene, vinyltoluene, α-methylstyrene and the like can be mentioned, and styrene is preferable. (C) Monomers having a carboxyl group As compounds belonging to this group, for example, compounds having a double bond and a carboxyl group in one molecule such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and fumaric acid Among them, preferred are mono- or dicarboxylic acids having 3 to 6 carbon atoms, and most preferred are acrylic acid and methacrylic acid.

(D) Monomers Having a Hydroxyl Group This group includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Compounds having a double bond and a hydroxyl group in one molecule, such as pentaerythritol tri (meth) acrylate and lactone-modified hydroxyl (meth) acrylate, are preferred. An alkyl group having 1 to 6 carbon atoms having a hydroxyl group is preferred. The most preferred is 2-hydroxyethyl (meth) acrylate. (E) Monomer having sulfonic acid (salt) group As a member belonging to this group, for example, sulfonic acid (salt) in one molecule such as styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt or ammonium salt Examples thereof include compounds having a group and a double bond, and preferred are sodium styrenesulfonate and sodium 2-sulfoethyl methacrylate.

(F) Monomers Having a Glycidyl Group Examples of the monomers belonging to this group include glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate. (G) Other (meth) acrylate monomers As those belonging to this group, for example, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, (meth) acrylamide, diacetone (meth) ) Acrylamide and the like. (H) Vinyl ester monomer As a member belonging to this group, for example, vinyl acetate ester, vinyl propionate ester, vinyl myristate ester, vinyl oleate ester, vinyl benzoate ester and the like can be mentioned.

(I) Crosslinkable Monomer The crosslinkable monomer used in the present invention has at least two polymerizable groups in one molecule. As members of this group, for example, aromatic divinyl compounds such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, oligo Ethylene glycol diacrylate, oligoethylene dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate,
Alkane polyol polyacrylates such as trimethylolpropane trimethacrylate or alkane polyol polymethacrylates can be mentioned. (J) Grafting monomer The grafting monomer used in the present invention has at least two polymerizable groups having different reactivity in one molecule. As members of this group, there can be mentioned, for example, unsaturated carboxylic acid allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate and diallyl itaconate.

A polymerizable monomer copolymerizable with (1) (2)
Is used in an amount of 40 to 9 per 100 parts by weight of the total monomer mixture.
9 parts by weight, preferably 50 to 95 parts by weight, more preferably 55 to 85 parts by weight. Among these (2), the above (a) or (b) is 20 to 9 in the total monomer mixture.
8.9 parts by weight, preferably 30 to 94.9 parts by weight are used. The above (c), (d) or (e) is desirably contained in 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the total monomer mixture. When the amount of these monomers is less than 0.1 part by weight, the stability of the emulsion of the copolymer may be reduced, and the emulsion may be aggregated when additives and the like are blended. In addition, agglomerates may be generated during spray coating, causing problems such as clogging of nozzles. On the other hand, if the amount is more than 10 parts by weight, the adhesion to the substrate may be too high to be able to be peeled off. The above (f) to (j) are the same for the total monomer mixture 1 respectively.
It can be used in an amount of 0 to 5 parts by weight, preferably 0 to 3 parts by weight in 00 parts by weight.

As the polymerization initiator used in the emulsion polymerization, persulfate polymerization initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate, azobisisobutyronitrile, 2,2'-azobis (2- Azo initiators such as amidinopropane) dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], dimethyl methylpropaneisobutyrate, cumene hydroperoxide, diisopropylbenzene hydroperoxide And organic peroxide initiators such as hydrogen peroxide, redox initiators consisting of peroxides such as tert-butyl hydroperoxide and reducing agents such as ascorbic acid, sodium formaldehyde sulfoxylate. It is possible, but not limited to these. The amount of the polymerization initiator used is 0.05 to 3 parts by weight per 100 parts by weight of all the monomer components. Examples of the surfactant include anionic surfactants such as sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, and sodium dialkyl sulfosuccinate; and (di) stearylbenzyldimethylammonium. Reactivity of cationic surfactants such as chloride, nonionic surfactants such as polyoxyethylene nonyl phenyl ether, polyoxyethylene monostearate, sodium alkyl allyl sulfosuccinate, sodium (meth) acryloyl polyoxyalkylene sulfate, etc. Examples of the surfactant include, but are not particularly limited to, surfactants. The amount of the surfactant used is 0.05 to 3 parts by weight per 100 parts by weight of all the monomer components.

Examples of the polymerization chain transfer agent include alkyl mercaptans such as hexyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan and n-tetradecyl mercaptan, for example, carbon tetrachloride , Carbon tetrabromide, halogenated hydrocarbons such as ethylene bromide, for example, mercaptocarboxylic acid alkyl esters such as 2-ethylhexyl thioglycolate and tridecyl mercaptopropionate, for example, methoxybutyl mercaptoacetate, mercaptopropion Alkoxyalkyl esters of mercaptocarboxylic acids such as methoxybutyl carboxylic acid, for example, mercaptoalkyl esters of carboxylic acids such as octanoic acid 2-mercaptoethyl ester; Le dimer, terpinolene, alpha-terpinene, .gamma.-terpinene, dipentene,
Examples thereof include anisole and allyl alcohol, but are not particularly limited thereto. The amount of the polymerization chain transfer agent is 0 to 100 parts by weight of all the monomer components.
5 parts by weight. In the method of the present invention, if necessary, the emulsion polymerization may be carried out in the presence of a chelating agent such as sodium ethylenediaminetetraacetate, a dispersant such as sodium polyacrylate or an inorganic salt such as sodium bicarbonate. good.

The particle size of the copolymer obtained from these raw materials by a conventionally known emulsion polymerization method is 50 to 700 n.
m, preferably 50 to 200 nm. When the particle size is smaller than this, the efficiency in actual production is reduced. On the other hand, when the particle size is larger than this, the workability at the time of coating may be reduced, and the efficiency in actual production is still poor. The particle size in the present invention indicates a weight average particle size, and is, for example, a dynamic light scattering measurement device (LPA-3000 / LPA-3100,
(Manufactured by Otsuka Electronics Co., Ltd.) using a dynamic light scattering method. Further, the gel fraction of the copolymer in the present invention is 30 to 99%, preferably 40 to 95%. If the gel fraction is smaller than this, sufficient strength cannot be obtained in the coating film upon peeling. In addition, the gel fraction here means
It means the toluene-insoluble matter determined by the measurement method described below. This gel fraction can be adjusted by selecting the type and amount of the chain transfer agent, the type and amount of the polymerization initiator at the time of polymerization, the polymerization temperature, and the like. In the present invention, by using the conjugated diene-based monomer (1), a flexible coating film can be obtained even when the gel fraction is high, so that it does not crack even at a temperature lower than the Tg of the coating film. A peelable coating is obtained. In contrast, in conventional acrylic emulsions that do not use a conjugated diene-based compound, in order to obtain sufficient coating strength at the time of peeling, if the gel fraction is to be increased, the crosslinkable monomer or the graftable monomer cannot be used. When these monomers are used in a large amount, the film formability deteriorates and the flexibility of the coating film becomes insufficient, so that the coating film may be broken when peeled off. . It is also possible to introduce ionic cross-links by metal oxides or hydroxides, but in this case, although film formability is obtained, flexibility of the coating film may not be obtained.

The Tg of the copolymer in the present invention is -30 to
50 ° C, preferably -20 to 40 ° C, most preferably-
15-30 ° C. If the Tg is lower than -30 ° C, the coating film becomes sticky, which is not preferable. On the other hand, when Tg exceeds 50 ° C., the film-forming properties deteriorate, and cracks occur in the coating film. Here, Tg is obtained from the following equation. _{1 / Tg = Σ (W n} / Tg n) (Tg: Tg viewed in absolute temperature of the copolymer, _Tg n:
Tg value expressed in absolute temperature of homopolymer of each component,
W _n : weight fraction of each component) Tg _{n of} homopolymer of each component
Is unique, for example, butyl acrylate is 233
K and methyl methacrylate are 403K. Using this formula, it is possible to prepare a copolymer having an arbitrary Tg, in which case there is no particular limitation on the type and composition of the monomer.

The copolymer emulsion thus obtained has a conjugated diene monomer (1) as a part of the monomer.
Is different from the conventional water-based temporary protective coating composition using only an acrylic monomer.
A coating film having a sufficient adhesion that does not easily peel off even at lower temperatures is obtained. Further, since the crosslinked structure is formed by copolymerizing the conjugated diene monomer (1), a protective coating film having excellent coating film strength can be obtained. The coating film can be easily peeled over a wide temperature range without breaking. Also,
By copolymerizing the conjugated diene monomer (1),
Since the water resistance of the coating film is improved, the coating film does not peel off due to rain or dew. When using only conventional acrylic monomers, the amount of surfactant and the amount of water-soluble monomer used must be strictly controlled in order to obtain sufficient water resistance of the coating film. As a result, the stability of the emulsion may be reduced. In addition, a protective coating using only an acrylic monomer can be left outdoors in summer, that is, exposed to sunlight and a high temperature for a long time, so that the adhesion of the coating to the material to be protected can be improved. And the coating film was torn off during peeling due to insufficient coating film strength. However, since the conjugated diene-based monomer (1) is copolymerized to form a crosslinked structure and improve the strength of the coating film, the coating film is torn when peeled even if the adhesive force is slightly increased. Nothing.

Further, the conventional aqueous temporary protective coating containing an acrylic emulsion has the drawback that the coating strength is weak at a temperature higher than Tg, so that the releasability is poor and that the coating is cracked at a temperature lower than Tg. Since the temporary protective coating has excellent coating strength, sufficient peelability can be obtained even at a temperature higher than Tg, and has sufficient coating strength even when peeled at a temperature lower than Tg, and is flexible without breaking during the peeling. A coating film having a characteristic is obtained. Examples of the weather stabilizer used in the present invention include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,1,3-tris (2-
Methyl-4-hydroxy-5-t-butylphenyl) butane, triethylene glycol-bis [3- (3-t-
Butyl-5-methyl-4-hydroxyphenyl) propionate], 3,9-bis [1,1-dimethyl-2-
{Β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4
A phenolic antioxidant such as 8,10-tetraoxaspiro [5.5] undecane, tris (2,4-di-t-
A phosphite-based antioxidant such as butylphenyl) phosphite, dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate;
Thioether antioxidants such as ditridecyl-3,3'-thiodipropionate, pentaerythritol-tetrakis (3-laurylthiopropionate), tetrakis [methylene-3- (dodecylthio) propionate] methane; 2- (5 -Methyl-2-hydroxyphenyl)
Benzotriazole, 2- (3,5-di-t-butyl-
Benzotriazole-based UV absorbers such as 2-hydroxyphenyl) -5-chlorobenzotriazole, benzophenone-based UV absorbers such as 2-hydroxy-4-octoxybenzophenone, tetrakis (1,2,2,6,6)
-Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate and other hindered amine-based light stabilizers, but are not particularly limited thereto. These weathering stabilizers can be used alone or in combination of two or more. In the aqueous temporary protective coating of the present invention, suppressing the oxidative deterioration of the conjugated diene compound is effective for the weather stability of the coating film, and a combination of a phenolic antioxidant and a thioether-based antioxidant is preferably used. .

In the present invention, the amount of these weathering stabilizers used is 0.01 to 5 per 100 parts by weight of the total monomer mixture.
Parts by weight, preferably 0.1 to 3 parts by weight.
If the amount is less than 0.01 part by weight, the weather resistance, which is a disadvantage of the conjugated diene copolymer, cannot be compensated. For example, when the film is left outdoors, such as in an automobile, the surface of the coating film may have cracks or cracks. May occur, and there may be a problem such as breakage in the middle of peeling. On the other hand, if it is more than 5 parts by weight, the raw material cost increases, which is not preferable for practical use.
The aqueous temporary protective coating of the present invention may further contain pigments such as titanium oxide, fillers such as calcium carbonate, inorganics,
Organic-based thickeners, paraffin wax, montan wax, carnauba wax, polyethylene wax, release aids such as silicone-based compounds and fluorine-based compounds, ethylene glycol alkyl ether, diethylene glycol alkyl ether, propylene glycol alkyl ether, dipropylene glycol Film forming aids such as alkyl ethers, drying aids such as lower alcohols, methylcellulose, ethylcellulose, carboxycellulose, hydroxylethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, water-soluble polymers such as polyvinylpyrrolidone, leveling agents, defoamers, Preservatives, pH adjusters and the like can be added. In the present invention, as a method of applying the composition to a substrate, for example, brush coating,
Examples include, but are not limited to, roller coating and spray coating.

[0019]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the Examples and Comparative Examples, “parts” means “parts by weight” unless otherwise specified. Abbreviations used in Examples and Comparative Examples are as follows. <Monomer> 1,3-butadiene Bdn-butyl acrylate BA methyl methacrylate MMA ethyl acrylate EA styrene St acrylic acid AA methacrylic acid MAA sodium styrene sulfonate NaSS 2-hydroxylethyl methacrylate HEMA 1,4-butylene glycol diacrylate BGA

<Surfactant> A 25% aqueous solution of sodium dodecylbenzenesulfonate (Neoperex F-25, manufactured by Kao Corporation) F-25 Sodium alkyldiphenyl ether sulfonate (Perex SSL, manufactured by Kao Corporation) SSL <Others> > Deionized water DIW Potassium persulfate (polymerization initiator) KPS ammonia (pH adjuster) AM sodium hydrogen carbonate SBC t-dodecylmercaptan (chain transfer agent) t-DMP 2-ethylhexyl thioglycolate (chain transfer agent) 2EH- TG

In calculating the Tg of the copolymer by the above formula, the following values are used as the Tg of the homopolymer of each component. Bd-80 ° C BA-40 ° C MMA 130 ° C EA-24 ° C St 105 ° C HEMA 55 ° C AA 87 ° C MAA 228 ° C BGA 100 ° C Method for measuring gel fraction: Flow the obtained copolymer emulsion into a glass mold, A film having a thickness of 0.3 mm is prepared. Cut this film into 2-3mm square, 0.4g
Weigh precisely. Put the sample in a sample bottle and add toluene 1
After being immersed in 00 ml and sealed, it is shaken in a shaking thermostat at 30 ° C. for 6 hours. Thereafter, the mixture is filtered through a 100-mesh wire net to determine the solid content of the filtrate, and the gel fraction is calculated from the sol solid content. Particle size measurement method: Measured by a dynamic light scattering method using a dynamic light scattering measurement device (LPA-3000 / LPA-3100, manufactured by Otsuka Electronics Co., Ltd.).

Example 1 (Production of Copolymer Emulsion A) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 630 g of Bd,
MMA 720g, St 396g, AA 18g, t-
1.8 g of DMP were added and stirred at 60 ° C. for 1 hour.
The reaction was performed for 5 hours. The obtained reaction mixture was cooled to 30 ° C., and adjusted to pH 8.5 using a 20% AM aqueous solution. Then, steam is blown into the reaction mixture to remove unreacted monomers, and the solid content of the emulsion is reduced to 5%.
After concentrating to 0%, copolymer emulsion A was obtained.

Example 2 (Preparation of Copolymer Emulsion B) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 450 g of Bd,
MMA 918 g, EA 360 g, MAA 36 g, t
-1.8 g of DMP was added and reacted at 60 ° C for 15 hours while stirring. The obtained reaction mixture was cooled to 30 ° C., and adjusted to pH 8.5 using a 20% AM aqueous solution. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid content concentration of 50% to obtain a copolymer emulsion B.

Example 3 (Production of Copolymer Emulsion C) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 576 g of Bd,
MMA 846 g, St 180 g, EA 144 g, N
18 g of aSS and 9 g of 2EH-TG were added, and the mixture was reacted at 60 ° C. for 15 hours with stirring. The resulting reaction mixture was cooled to 30 ° C., and using a 20% AM aqueous solution,
The pH was adjusted to 8.5. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid content concentration of 50% to obtain a copolymer emulsion C.

Example 4 (Production of Copolymer Emulsion D) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 504 g of Bd,
MMA 396 g, St 396 g, EA 450 g, M
18 g of AA and 1.8 g of 2EH-TG were added, and the mixture was reacted at 60 ° C. for 15 hours with stirring. The resulting reaction mixture was cooled to 30 ° C., and using a 20% AM aqueous solution,
The pH was adjusted to 8.5. Subsequently, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid content concentration of 50% to obtain a copolymer emulsion D.

Example 5 (Production of Copolymer Emulsion E) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 774 g of Bd,
MMA 990 g, MAA 18 g, AA 18 g, t-
5.4 g of DMP was added, and stirred at 60 ° C. for 1 hour.
The reaction was performed for 5 hours. The obtained reaction mixture was cooled to 30 ° C., and adjusted to pH 8.5 using a 20% AM aqueous solution. Then, steam is blown into the reaction mixture to remove unreacted monomers, and the solid content of the emulsion is reduced to 5%.
After concentration to 0%, a copolymer emulsion E was obtained.

Example 6 (Production of Copolymer Emulsion F) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of a 10% SSL aqueous solution, 450 g of Bd,
MMA 810 g, BA 360 g, HEMA 144
g and 1.8 g of t-DMP, and add 60 g with stirring.
The reaction was performed at 150C for 15 hours. The resulting reaction mixture is
Cool to 0 ° C. and use a 20% AM aqueous solution, pH 8.5
Was prepared. Then, steam is blown into the reaction mixture,
Unreacted monomers were removed, and the emulsion was further concentrated to a solid content concentration of 50% to obtain a copolymer emulsion F.

Example 7 (Production of Copolymer Emulsion G) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 183.6 g of a 10% SSL aqueous solution, and Bd 450
g, 495 g of MMA, 90 g of EA, 9 g of AA, t
1.08 g of -DMP was added, and the mixture was reacted at 60 ° C for 10 hours while stirring. The first stage polymerization addition rate is 95%
After confirming the above, as a second stage preparation, 122.4 g of a 10% SSL aqueous solution, 180 g of Bd,
378 g of MMA, 144 g of EA, 18 g of AA, t
0.72 g of -DMP was added, and after 5 minutes, 72 g of a 2% aqueous KPS solution was added, and the mixture was reacted at 60 ° C for 10 hours with stirring. The obtained reaction mixture was cooled to 30 ° C., and adjusted to pH 8.5 using a 20% AM aqueous solution.
Then, steam is blown into the reaction mixture to remove unreacted monomers, and the solid content of the emulsion is reduced to 50%.
Then, a copolymer emulsion G was obtained.

Comparative Example 1 (Production of Copolymer Emulsion H) DIW 152 was placed in a polymerization vessel equipped with a 5-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. Continue at 70 ° C
936 g of MMA, 810 g of BA, AA 1
A monomer emulsion composed of 8 g, 612 g of a 5% aqueous SSL solution, and 306 g of a 1% aqueous SBC solution was dropped over 300 minutes. After the dropwise addition, the temperature was raised to 80 ° C., and the mixture was further stirred for 60 minutes to perform an aging reaction. The obtained reaction mixture is kept at 30 ° C.
The mixture was cooled to pH 8.5 using a 20% AM aqueous solution. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid concentration of 50% to obtain a copolymer emulsion H.

Comparative Example 2 (Production of Copolymer Emulsion I) DIW 152 was placed in a 5-liter polymerization vessel equipped with a reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. Continue at 70 ° C
567 g of MMA, 1152 g of EA,
36 g, BGA 9 g, 5% SSL aqueous solution 612 g,
A monomer emulsion consisting of 306 g of a 1% SBC aqueous solution was added to 3
It was added dropwise over 00 minutes. After the dropwise addition, the temperature was raised to 80 ° C., and the mixture was further stirred for 60 minutes to perform an aging reaction. The obtained reaction mixture was cooled to 30 ° C., and adjusted to pH 8.5 using a 20% AM aqueous solution. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid content of 50% to obtain a copolymer emulsion I.

Comparative Example 3 (Production of Copolymer Emulsion J) DIW 152 was placed in a 5-liter polymerization vessel equipped with a reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. Continue at 70 ° C
162 g MMA, 1566 g EA, MAA
A monomer emulsion composed of 36 g, 612 g of a 5% SSL aqueous solution, and 306 g of a 1% SBC aqueous solution was dropped over 300 minutes. After the dropwise addition, the temperature was raised to 80 ° C., and the mixture was further stirred for 60 minutes to perform an aging reaction. The resulting reaction mixture is
It cooled to ° C and adjusted to pH 8.5 using 20% AM aqueous solution. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid concentration of 50% to obtain a copolymer emulsion J.

Comparative Example 4 (Production of Copolymer Emulsion K) DIW 152 was placed in a polymerization vessel equipped with a 2-liter reflux condenser.
8.2 g and 7.2 g of F-25 were charged and heated to 60 ° C. while stirring under a nitrogen stream. After heating, MMA 36g
And stirred for 10 minutes, and then a 2% KPS aqueous solution 180
g was added to obtain a seed latex. This seed latex was charged into a 5-liter autoclave purged with nitrogen, 306 g of 10% SSL aqueous solution, Bd 1170
g, MMA 576 g, MAA 18 g, t-DMP
1.8 g was added, and the reaction was carried out at 60 ° C. for 15 hours with stirring. The resulting reaction mixture was cooled to 30 ° C.
The pH was adjusted to 8.5 using a 20% AM aqueous solution. Then, steam was blown into the reaction mixture to remove unreacted monomers, and the emulsion was further concentrated to a solid concentration of 50% to obtain a copolymer emulsion K.

Using the copolymer emulsions A to K obtained in Examples 1 to 7 and Comparative Examples 1 to 4, tests for mechanical stability, peelability, breaking strength and breaking elongation described below were performed. The results were summarized in [Table 1]. [Mechanical stability]
The measurement was performed according to the mechanical stability measurement method described in K6387. That is, 50 g of each of the copolymer emulsions A to K was used as a sample, and after rotating for 10 minutes under a load of 10 kg, the mixture was filtered through an 80-mesh wire gauze, and the ratio of aggregates remaining on the wire gauze was examined to evaluate the mechanical stability. went. ◎: Nothing remains on the wire mesh (0.01% or less) 極: A very small amount of aggregate remains on the wire mesh (1.0% or less) ×: A large amount of aggregate remains on the wire mesh (1.0%) %that's all)

[Peelability] An acrylic melamine-based clear paint was applied to the electrodeposited steel plate and baked at 150 ° C. for 30 minutes to obtain a coated test plate. Example using a doctor blade on this coating test plate, so that the dry coating film is 50 μm,
And the emulsion of the comparative example was apply | coated, and it dried for 10 minutes by the 50 degreeC ventilation dryer. Thereafter, the coating film left for 3 days in a thermo-hygrostat at 25 ° C. and a relative humidity of 50% was used for tests of peelability, breaking strength and breaking elongation. Cut the above coating film with a cutter to a width of 25 mm.
The coating film was peeled at a temperature of 5 ° C. and 70 ° C. at a speed of 200 mm / min. The evaluation was performed based on the following criteria. ：: Easy peeling ：: Peeling is possible with a little resistance but no problem. が あ る: Peeling is possible with some resistance. X ( ^* 1): The coating film is broken and cannot be peeled into a sheet. X ( ^* 2): The coating film stretches and tears and cannot be peeled off × ( ^* 3): The adhesive force is too strong to peel off A 25 mm wide test piece is cut out from the above-mentioned coating film with a cutter and Autograph (manufactured by Shimadzu Corporation) is used. And a tensile test was performed. At each temperature of −20 ° C., 25 ° C., and 70 ° C., the tensile strength was 200 mm / min, and the breaking strength and elongation were measured.

[0035]

[Table 1]

Examples 8 to 12 and Comparative Examples 5 and 6 The copolymer emulsions A and D obtained in Examples 1 and 4 were combined with the following water dispersions of pigments, thickeners, defoamers, In addition, the weather-resistant stabilizers shown in Table 2 were mixed with stirring and blended to prepare aqueous temporary protective coating compositions. Of the weathering stabilizers shown in Table 2, those which cannot be directly blended are added to 100 parts of the weathering stabilizer.
Part of sodium dioctylsulfosuccinate (Neocol P, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and DIW to add 20%
Was used as an aqueous dispersion.

Preparation of aqueous dispersion of pigment: 180 parts of titanium oxide white (Type R-930, manufactured by Ishihara Sangyo Co., Ltd.) and 0.9 parts of Orotan 731DP as a dispersant (manufactured by Rohm and Haas Co., Ltd.) , DIW 72 parts, glass beads were added, and the mixture was dispersed with a sand mill disperser for 60 minutes to obtain an aqueous pigment dispersion. Paint formulation: Copolymer emulsion 100 parts Pigment aqueous dispersion 10 parts Defoamer BYK-022 (manufactured by Big Chemie) 1 part Thickener ASE-60 (manufactured by Nippon Acryl Chemical Co., Ltd.) 0.05 part

[Weather resistance] The obtained water-based paint was applied to the coating test plate used for the above-mentioned peeling test so that the dry coating film became 50 μm with a doctor blade, and was blown at 50 ° C. for 10 minutes. After drying, 25 ° C, 50% relative humidity
Was left for 3 days in a thermo-hygrostat. Thereafter, a weather resistance acceleration test was performed with a sunshine weatherometer, and the appearance of the coating film after irradiation for 400 hours was visually evaluated. The criteria are as follows. : No change ×: Cracks are observed on the coating film surface [Releasability] In addition, the above coating film was cut in a width of 25 mm with a cutter, and 200 mm at -20 ° C, 25 ° C, and 70 ° C, respectively. The coating was peeled off at a rate of / min.
The evaluation was performed according to the following criteria. ：: easily peelable ○: slightly resistable but can be peeled off without any problem △: there is resistance but somehow peelable ×: not peelable

[0039]

[Table 2]

[0040]

The water-based temporary protective coating composition of the present invention can be used to protect automobile exterior coatings from scratches, dirt, and deterioration, to protect glass and woodwork products from scratches and dirt, or to protect dirt from ventilation fans and the like. The film can be easily peeled in a wide range of temperature environments compared to conventional ones, maintains adhesion at low temperatures and maintains film strength that does not break when peeled. It has features such as doing.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 133/10 C09D 133/10 201/02 201/02 (72) Inventor Ichiro Sasaki Yodogawa-ku, Osaka-shi, Osaka 2-17-17, 13-Honcho Takeda Pharmaceutical Co., Ltd.F-term in Chemicals Company (reference) KA12 MA08 MA10 MA13 NA10 NA12 PA18 PB02 PB07 PC03 PC06 PC07 PC08

Claims (10)

[Claims] 1 to 60 parts by weight of 100 parts by weight of the total monomer mixture
Of a conjugated diene-based monomer (1) and 40 to 99 parts by weight of (1) and a monomer mixture comprising a polymerizable monomer (2) copolymerizable with (1). An aqueous temporary protective coating composition comprising a polymer emulsion. 2. The aqueous temporary protective coating composition according to claim 1, further comprising 0.01 to 5 parts by weight of a weathering stabilizer per 100 parts by weight of the total monomer mixture. 3. A polymerizable monomer (2) copolymerizable with (1).
The aqueous temporary protective coating composition according to claim 1, wherein the composition contains an alkyl (meth) acrylate having 1 to 20 carbon atoms or an aromatic vinyl compound. 4. An alkyl (meth) acrylate having 1 to 20 carbon atoms or an aromatic vinyl compound, which is a total monomer mixture 10
The aqueous temporary protective coating composition according to claim 3, wherein the composition contains 20 to 98.9 parts by weight based on 0 part by weight. 5. A polymerizable monomer (2) copolymerizable with (1).
2. The composition according to claim 1, wherein the compound contains 0.1 to 10 parts by weight of a monomer having at least one carboxyl group, hydroxyl group or sulfonic acid (salt) group per molecule in 100 parts by weight of the total monomer mixture. Aqueous temporary protective coating composition. 6. A weathering stabilizer comprising a phenolic antioxidant, a phosphite antioxidant, a thioether antioxidant,
The aqueous temporary protective coating composition according to claim 2, which is a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber or a hindered amine-based light stabilizer. 7. The aqueous temporary protective coating composition according to claim 1, wherein the conjugated diene monomer (1) is 1,3-butadiene. 8. An alkyl (meth) acrylate having 1 to 20 carbon atoms is methyl methacrylate, ethyl acrylate,
The aqueous temporary protective coating composition according to claim 3, wherein the composition is butyl acrylate, 2-ethylhexyl acrylate or isononyl acrylate, and the aromatic vinyl compound is styrene. 9. The water-based temporary protective coating composition according to claim 1, which is used for temporarily protecting a painted outer plate or an exterior part of an automobile. 10. A temporary protective coating obtained by applying the aqueous temporary protective coating composition according to any one of claims 1 to 8 to the surface of a material to be protected and drying.