JPH07278468A - Water-based peelable coating composition - Google Patents

Abstract

PURPOSE:To obtain a water-based peelable coating compsn. useful for temporary protection of the surface of a coated article and stable against heat and light. CONSTITUTION:This water-based peelable coating compsn. comprises, as the main components (A), an acrylic resin having a carboxylated monomer unit content of at most 5wt.%, a glass transition temp. of 5 to 30 'C and a wt.- average mol.wt. of at least 20,000, and prepd. from a (meth)acrylic ester as the indispensable component either alone or in combination with other polymerizable monomer [except for (meth)acrylonitrile] if necessary, (B) a water repellent, and (C) an ultraviolet absorber.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a releasable aqueous coating composition useful for temporarily protecting the surface of a coated article, especially the composition containing no or little organic solvent. .

[0002]

2. Description of the Related Art: The surface to be coated of metal products such as automobiles, vehicles, machine parts and household products, woodworking products, glass products, plastic products and rubber products, etc., is temporarily protected. Things are commonplace.

[0003] For example, from the completion of these coated products to reaching the customers, during storage in outdoor stockyards, during transportation by self-transportation, railroads, trailers, ships, etc.
Scratches on the coating film due to contact with other objects, dust in the air, iron powder, salts, soot, bird droppings, body fluids and carcasses of insects, sun rays, scratches due to wind and rain (particularly acid rain), stains,
Discoloration, pollution, etc. will occur and its commercial value will decrease, so
To prevent this, temporary protection is provided from the time the finished product is completed to the time it reaches the customers. Conventionally, various methods as described below have been carried out to temporarily protect such a coated product, but none of them are sufficient.

An aliphatic hydrocarbon solvent dispersion of waxes is applied. To remove (peel) the applied temporary coating, an emulsion in which a cleaning agent is dispersed in a hydrocarbon solvent or water is used. For example, when this is applied to automobiles, it is applied to the inside of doors and hinges. The rust preventive agent and rust preventive wax that are present are also removed at the same time, and the coating film swells with these solvents, and there are environmental problems such as fire hazard and wastewater treatment.

A wax-solid powder organic solvent type dispersion in which solid powder is mixed with wax to lower the strength of the wax coating and the protective coating can be easily removed by hand-wiping. this is,
Temporary protection is inferior, it easily falls off when touched by hands, and it is easily contaminated by acid rain.

Emulsions containing an acrylic resin as a main component are known as water-based temporary protectors. However, all of them contain a large amount of a carboxyl group-containing monomer such as acrylic acid or methacrylic acid, and therefore, peeling is caused. It is difficult to remove with an alkaline aqueous solution, requires a large number of steps, and has a problem in wastewater treatment.

Further, as a temporary water-based protective agent (meth)
Acrylic resin emulsions containing acrylonitrile are known, and these have excellent coating strength and releasability, but since they contain (meth) acrylonitrile, it is difficult to dispose of the release coating. For example, if the coating film is buried in the ground, there is a possibility of water pollution, and if incinerated, hydrogen cyanide gas may be generated to pollute the atmosphere.

Aqueous vinyl acetate resins are also known, but their acid resistance and water resistance are not sufficient.

Further, it is important that the composition for temporary protection has the following characteristics.

A) It has a proper adhesion to the coating film to be protected, and when peeling, it can be peeled as one continuous sheet manually or by high-pressure water flow without damaging the coating film. B) Spray painting, roller painting, or brush painting is possible. C) It has excellent protection functions such as acid rain, stains caused by iron powder, etc., prevention of contamination, contact with objects, and scratches due to chipping. D) The film has appropriate elasticity, strength, elongation and durability, and has little tackiness. E) It has the water resistance, weather resistance, and thermal stability required for outdoor storage. F) A solvent that swells the coating film to be protected or causes abnormalities in the coating surface such as deformation, discoloration, stains, and blurring,
It does not contain additives such as plasticizers and dispersants. G) Since the peeled coating is discarded,
Since it is landfilled or incinerated, it contains no components that are harmful to the human body or the environment.

[0011]

Means for Solving the Problems The present inventors have
In order to solve the above problems and to develop a strippable aqueous temporary protective coating composition having the above-mentioned properties a) to g), as a result of intensive research, a specific acrylic emulsion resin containing no acrylonitrile was obtained. When an aqueous coating composition containing a water repellent and an ultraviolet absorber is used, even if it is exposed to sunlight for a long time, it can be easily peeled off without lowering the film strength and elongation, and has a protective function against acid rain etc. It was found that a coating film which is excellent and has no environmental problem even in landfilling or incineration after peeling is obtained, and the present invention has been completed.

That is, the present invention comprises (A) a (meth) acrylic acid ester as an essential component and, if necessary, other polymerizable monomers (however, excluding (meth) acrylonitrile) in combination, and contains a carboxyl group. Monomer content is 5
An acrylic resin having a weight% or less, a glass transition temperature of 5 to 30 ° C. and a weight average molecular weight of 20,000 or more,
It relates to a releasable aqueous coating composition containing (B) a water repellent and (C) an ultraviolet absorber as main components.

Component (A): A (meth) acrylic acid ester as an essential component, and optionally other polymerizable monomers (however, excluding (meth) acrylonitrile) are used in combination, containing a carboxyl group-containing monomer. Acrylic resin having a ratio of 5% by weight or less, a glass transition temperature of 5 to 30 ° C. and a weight average molecular weight of 20,000 or more.

Examples of the (meth) acrylic acid ester include esterified products of acrylic acid or methacrylic acid and a monohydric alcohol having 1 to 28 carbon atoms, such as methyl acrylate, methyl methacrylate, ethyl acrylate and methacrylic acid. Ethyl, n-butyl acrylate, n methacrylate
-Butyl, acrylic acid iso-Butyl, methacrylic acid iso
-Butyl, tert-butyl acrylate, tert-methacrylic acid
-Butyl, propyl acrylate, propyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate , Cyclohexyl methacrylate, stearyl acrylate, stearyl methacrylate and the like.

Further, hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate are also included in the (meth) acrylic acid ester.

Other polymerizable monomers are other than the above-mentioned (meth) acrylic acid ester and (meth) acrylonitrile, and include, for example, styrene, vinyltoluene, methylstyrene, chlorostyrene, divinylbenzene, vinyl acetate, vinyl chloride, vinyl. Examples thereof include sulfonic acid group-containing monomers such as isobutyl ether, methyl vinyl ether, 2-ethylhexyl vinyl ether, and sulfoethyl methacrylate salts, and amide group-containing monomers such as acrylamide and methacrylamide.

In the component (A), the mixing ratio of the (meth) acrylic acid ester and the other polymerizable monomer is not particularly limited, but based on the total amount of both components, the (meth)
Acrylic ester is 1 to 100% by weight, preferably 5
0 to 99.8% by weight, more preferably 80 to 99.8% by weight, other polymerizable monomer is 99 to 0% by weight, preferably 50 to 0.02% by weight, more preferably 20 to 0.0%.
It is 2% by weight.

Further, the component (A) may contain (copolymerization) a carboxyl group-containing monomer in an amount of 5% by weight or less, preferably 0.1 to 3% by weight. 5% by weight
When the amount is larger, the adhesion to the coating film to be protected is high and the peeling property of the coating becomes difficult, which is not preferable. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid.

The component (A) is a nonionic surfactant, an anionic surfactant, a reactive surfactant having a copolymerizable unsaturated group, etc. according to a conventionally known method using a predetermined amount of the above-mentioned monomer. It can be obtained by emulsion polymerization using a polymerization initiator in the presence of one kind or two or more kinds of the emulsifier. It can also be obtained by known suspension polymerization other than emulsion polymerization.

The acrylic copolymer (A
Component), regarding the glass transition temperature (Tg),
The temperature is 5 to 30 ° C, preferably 6 to 20 ° C. 5 ° C
If it is less than the above range, the adhesiveness of the obtained coating film increases and the coating film strength also decreases, so that the peelability over time decreases. If the temperature is higher than 30 ° C, the film-forming property will be impaired, and
When applied at an ambient temperature of 0 ° C., the resulting coating becomes cracked and a continuous coating cannot be obtained. Also,
The weight average molecular weight of the component (A) is preferably 20,000 or more, particularly preferably 30,000 to 100,000.
When it is less than 00, the film strength is lowered, and the releasability is extremely lowered.

Component (B): Water repellent The coating film of the composition of the present invention has appropriate adhesion to the surface of the coating film to be protected and can be completely peeled off without damaging the coating film. With the use of the water repellent, it becomes possible to maintain the above function remarkably for a long time (3 to 5 times).

As the water repellent, at least one compound selected from wax, silicon, fluorine and the like can be preferably used. These may be used either in the form of being dissolved or dispersed in water or in the form of powder.

Specific examples of the waxes include plant-based; candeli wax, carnauba wax, rice wax, wood wax, jojoba oil, and the like; animal-based; beeswax, lanolin, whale wax, and other minerals; montan wax, ozokerite, Petroleum-based such as ceresin; synthetic hydrocarbon-based such as paraffin wax, microcrystalline wax, petrolatum; modified wax-based such as Fischer-Tropsch wax, oxidized polyethylene wax, polyethylene wax, acryl-ethylene copolymer wax;
Montan wax derivative, paraffin wax derivative,
Hydrogenated wax such as microcrystalline wax derivative; hardened castor oil, hardened castor oil derivative, etc .; 12-hydroxystearic acid, stearic acid amide, phthalic anhydride imide, bisamide, amide, glycerin ester, sorbitan ester, higher alcohol (C ₁₂ Or higher, preferably C ₁₈ or higher), higher fatty acid (C
₁₂ or more, preferably C ₁₈ or more).

These wax systems have a melting point of about 15-25.
Those having a range of 0 ° C, preferably about 20-180 ° C are desirable. If the melting point deviates from the above range, the water resistance and acid resistance of the coating may decrease.

As the silicon-based compound, silicon oil having a siloxane bond as a main skeleton, silicon powder, emulsion, water-soluble resin and the like can be used. Specifically, dimethylpolysiloxane type, methylphenylpolysiloxane type, cyclic dimethylpolysiloxane type, fluoropolysiloxane type, modified (amino, epoxy, polyether, alcohol, fluorine, mercapto, carboxyl, alkyl higher fatty acid, for example, trade name (Torre Silicone Co., Ltd.
SH203, BY16-828, SF841
1, SF8418, BY16-838, SF8422,
BY16-848, SH3771, SH3746, SF
Silicon oil such as 8419, FS1265; R90
0, R901, R902, F100, F101, F20
0, F201, F202, F203, F400, F30
0, F301, F250, E500, E501, E60
Silicon powders such as 0, E601, E602, E603, E850; SH204, SH490, SH7024,
Emulsions such as SH7028, SH7036, SH7060; SH3746, SH3749, SH3771
Examples of such aqueous resins include: The above silicon powder is usually about 0.1 to 100 μm, preferably about 5 to 5
It can have an average particle size of 0 μm.

Among them, it is sparingly soluble in water and can be easily formed into an aqueous dispersion with a small amount of a surfactant, and is sufficiently oriented in the lower layer of the film to form an interface with the film to be protected. The polyether-modified silicone oil represented by the following general formula is most suitable because it has an excellent function of alleviating the increase in the adhesion force with time.

[0027]

[Chemical 1]

(In the formula, POA represents a polyether moiety by modification with ethylene oxide or propylene oxide.)

The fluorine-based compound has a molecular weight of about 1,000 to 2 containing a fluoroalkyl group in the molecule.
Those of 10,000 are preferable. Specific examples thereof include perfluoroalkylcarboxylic acid salt, perfluoroalkylphosphoric acid ester, perfluoroalkylcarboxylic acid salt, perfluoroalkyltrimethylammonium salt, perfluoroalkylpentanone and perfluoroalkylEO adduct.

Further, as the trade name (product of Asahi Glass Co., Ltd.), Surflon S-111, Same as left S-112, Same as left S-1
13, Same as left S-121, Same as left S-131, Same as left S-13
2, same left S-142, same left S-145, same left 131S,
Same as the left 145S and the like.

Among these water repellents, the use of a wax type and a silicon compound has an advantage that a film excellent in water resistance and acid resistance can be easily obtained.

The proportion of the water repellent used is usually about 0.5 to 30 parts by weight, preferably about 1 to 20 parts by weight, in the case of wax, relative to 100 parts by weight (solid content) of the acrylic resin (A). Part, in the case of a silicon compound, about 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and in the case of a fluorine-based compound, about 0.01 to 5 parts by weight, preferably about 0.01 to
3 parts by weight is desirable.

Component (C): Ultraviolet Absorber The purpose of using the ultraviolet absorber is to prevent light from being left outdoors for several months or more if only the acrylic resin (A) or the mixture with the water repellent (B) is used. Due to deterioration, the elongation of the coating is extremely reduced. Therefore, when peeling, it is easily scratched and a large number of peeling steps are required. The main purpose of using the component (C) is to prevent photodegradation of such a coating and obtain a good peelability after protection for a long period of time.

Therefore, the above-mentioned (A) acrylic copolymer,
By using the three components of (B) water repellent and (C) ultraviolet absorber together, it becomes possible to prolong the protection period, and it becomes possible to perform the peeling work in an extremely short time.

As the UV absorber (C) used in the present invention, any known one can be used. Specific examples thereof include salicylic acid derivatives such as phenyl salicylate, p-octylphenyl salicylate and 4-tert-butylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy- 4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5
-Sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone,
2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, sodium 2,2'-dihydroxy-4,4 '
-Dimethoxy-5-sulfobenzophenone, 2,2 ',
4,4′-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 5-chloro-2-hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoylresorcinol,
4,6-dibenzoylresorcinol, hydroxydodecylbenzophenone, 2,2'-dihydroxy-4 (3
-Benzophenone-based compounds such as methacryloxy-2-hydroxypropoxy) benzophenone; benzotriazole-based compounds such as 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and other compounds such as oxalic acid anilide and cyanoacrylate Is mentioned.

The ultraviolet absorber (C) can be used in combination with a light stabilizer. As the light stabilizer, a conventionally known one can be used. Specifically, bis- (2,2 ', 6,6
'-Tetramethyl-4-piperidinyl) sebatate, 4
-Benzoyloxy-2,2 ', 6,6'-tetramethylpiperidine and the like are preferable.

The blending amount of the component (C) can be arbitrarily selected according to the purpose, but per 100 parts by weight of the component (A),
0.1 to 10 parts by weight, especially 0.3 to 5 parts by weight are suitable.

The composition of the present invention comprises, for example, an aqueous emulsion of the (A) acrylic copolymer in water, (B) a water repellent and (C) an ultraviolet absorber, which is used as an aqueous resin. It can be obtained by mixing with or by dispersing in powder form. The water repellent and the ultraviolet absorber can be emulsified by a method such as mechanical dispersion or dispersion with an emulsifier.

If necessary, the composition of the present invention may be dispersed in water by using a surface active agent or a water-soluble resin with a known coating surface adjusting agent, defoaming agent, thickening agent, coloring agent, filler or the like. It can be mixed with the body. In particular, by adding titanium white as an aqueous dispersion and then blending it, a whitened film can be obtained, and by whitening, it is possible to enhance the barrier effect against ultraviolet rays, heat and the like.

The composition of the present invention can be applied by brush coating, roller coating, spray coating, or any other conventional coating method. The coated film is applied at room temperature for 1 hour or 2 hours. By heating for 20 minutes at 50 ° C. or 10 minutes at 70 ° C. for heating for a time, a dry state that does not melt down even if exposed to rain immediately after drying can be obtained. Furthermore, after irradiating with mid-infrared rays or far-infrared rays for 30 seconds or 1 minute, the temperature is increased from 50 ° C to
By heating at an ambient temperature of 0 ° C. for 2 to 3 minutes, the drying time can be shortened.

As the article to be coated, it is particularly effective when applied to moldings, laminates, coatings, casts, decorative sheets mainly composed of thermosetting resin, but iron, It can be applied to various products mainly made of wood products, glass, and synthetic resins other than thermosetting resins.

[0042]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. In addition, "part" and "%" in an Example and a comparative example are a basis of weight.

(I) (A) Production Example of Acrylic Resin Emulsion [A-1] Deionized water 31 was added to a 2-liter four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a dropping funnel.
2 parts, Newcol 707SF (manufactured by Nippon Emulsifier, solid content 30)
(Wt%) 2.3 parts was added, and after the atmosphere was replaced with nitrogen, the temperature was maintained at 80 ° C.
Immediately before dropping the pre-emulsion having the following composition, 0.7 part of ammonium persulfate was added, and the pre-emulsion was dropped over 3 hours.

<Composition of pre-emulsion> Deionized water 350 parts Methyl methacrylate 440 parts n-Butyl acrylate 352 parts Acrylic acid 8 parts Newcol 707SF 53.3 parts Ammonium persulfate 1.5 parts

After 30 minutes from the completion of the reaction, a solution prepared by dissolving 0.7 parts of ammonium persulfate in 7 parts of deionized water was added dropwise over 30 minutes, and the temperature was kept at 80 ° C. for 2 hours.
Then, the temperature was lowered to 40 to 60 ° C. and the pH was adjusted to 7 to 8 with aqueous ammonia to obtain an acrylic emulsion A-1.
The resulting acrylic emulsion has a resin Tg of 13.5.
° C, weight average molecular weight of about 30,000, nonvolatile content of 51.7
%, The viscosity was 680 cps, and the average particle size was 0.2 μm.

Acrylic emulsions [A-2] to [A-6] were obtained in the same manner as in [A-1] except that the type of vinyl-based monomer was changed and the formulations shown in Table 1 were used.

[0047]

[Table 1]

* 1 The particle size is Coulter No. The average particle diameter measured in 4 is shown. * 2 Nonvolatile matter was calculated by heating the sample at 150 ° C for 30 minutes and measuring the remaining amount. * 3 Viscosity is the value measured with a B-type viscometer at a rotation speed of 60 rpm.

(II) Next, the wax emulsion (B-
1) to (B-3) will be described. Paraffin wax (MP46 ° C), Montan wax, Hi-Mic-1
20 parts of 080 (manufactured by Nippon Seiro Co., Ltd., Microstarin wax) are placed in separate glass containers, and then sorbitan monostearate 1 is placed in each of these containers.
Parts, polyoxyethylene stearyl ether 3 parts, water 7
6 parts were mixed and heated and stirred at 80 to 90 ° C. to obtain a wax emulsion having a solid content of 20%. Paraffin wax corresponds to wax (B-1), montan wax corresponds to wax (B-2), and Hi-Mic-1080 corresponds to wax (B-3).

(III) Production Example of Silicone Oil Emulsion To 30 parts of modified silicone oil TSF4452 (Toshiba Silicone, polyether modified silicone oil), 2 parts of polyoxyethylene sorbitan monooleate and 68 parts of water were added and well stirred, A silicone oil emulsion (B-4) having a solid content of 30% was obtained. Of the (B) water repellents, those which cannot be blended into the (A) acrylic emulsion as they are, can be blended by forming an aqueous dispersion using a surfactant as described above. Is.

(IV) Examples and Comparative Examples The water repellents (B-1) to (B-4) were added to 100 parts of the resin solid content of the acrylic emulsions [A-1] to [A-6]. The water repellents (B-1) to (B-4) and the ultraviolet absorber were mixed and mixed in the types and the blending amounts (solid content) shown in Tables 2 and 3 by stirring. Regarding the composition of the ultraviolet absorber, a liquid material at room temperature or a material having a melting point not higher than the reaction temperature during resin production was selected.

Amino alkyd resin paint (manufactured by Kansai Paint Co., Ltd., trade name Amilak) is applied to mild steel plates (thickness 0.7 mm) surface-treated with Palbond 3050 from these compositions.
Is spray-coated on a coated plate baked at 140 ° C for 30 minutes and dried at 70 ° C for 10 minutes to give a film thickness of 5
A peelable coating having a thickness of 0 to 70 μm was formed. The performance test results of the coating compositions of Examples and Comparative Examples are summarized in Tables 2 and 3.

[0053]

[Table 2]

[0054]

[Table 3]

(* 1) Water repellent SH204: Toray Silicone Co., Ltd., trade name, emulsion, solid content 35% Surflon S-112: Asahi Glass Co., Ltd., trade name, perfluoroalkyl phosphate ester, water / Isopropanol liquid, solid content 15% Surflon S-141: Asahi Glass Co., Ltd., trade name, perfluoroalkylamine oxide, water / isopropanol liquid, solid content 30%

(* 2) UV absorber and light stabilizer UV absorber TINUVIN 1130: Ciba Geigy Co., Ltd., trade name, liquid, benzotriazole derivative

[0057]

[Chemical 2]

Sandbore 3206: trade name, liquid, ethanediamide N- (2-ethoxyphenyl) -N '-(4-isododecylphenyl), manufactured by Sand Corp.

[0059]

[Chemical 3]

Light Stabilizer Sanol LS-744: manufactured by Sankyo Co., Ltd., trade name, powder,
4-benzoyloxy-2,2 ', 6,6'-tetramethylpiperidine

Test method (* 3) Immediately after spray coating so that the dry film thickness is 60 to 70 μm, the ambient temperature is 20 ° C. and the wind speed is 0.5 to
After standing for 1 hour under the condition of 0.7 m / s, the state of the coated surface was observed. ○: No abnormality. A continuous film is formed. Δ: Crack-like abnormality is recognized in 30% or less of the coated surface. X: Crack-like abnormality is recognized on 30% or more of the coated surface.

(* 4) Ease of peeling when the peelable coating composition coating applied to the test plate was peeled off from the edge at a speed of 1 m / 30 seconds after standing for 1 day at 20 ° C. after formation of the coating Was tested. ⊚: Can be peeled off very easily. ◯: Can be easily peeled off. □: Slightly heavy. Δ: Heavy but peelable. Δ ^* : The coating is brittle and does not easily peel off into a sheet. X: Not peelable.

(* 5) After leaving the test plate at 80 ° C. for 300 hours, the peeling test was conducted in the same manner as in (* 4). (* 6) QUV using an accelerated weather resistance tester manufactured by Q Panel
According to accelerated baculo test. Test conditions: UV irradiation 16 H / 70 ° C. Water condensation 8 H / 50 ° C. was set as one cycle and tested for 480 hours (20 cycles), and then the ease of peeling was tested by the same method as (* 4).

After the film was peeled off in the tests of (* 7) and (* 4), the presence or absence of swelling or other coating surface abnormality of the coating material, aminoalkyd coating, was observed. ○: No abnormality. Δ: Light swelling is recognized. X: Remarkable swelling is recognized.

(* 8) 0.4 ml of 40% sulfuric acid was spotted on the coating film, heated at 60 ° C. for 15 minutes, washed with water, and then the coating film was peeled off to swell, gloss, and etch the lower aminoalkyd coating film. The presence or absence of traces was observed. ○: No abnormality. Δ: Swelling is recognized. X: Luster and etching are recognized.

(* 9) Iron powder is sprinkled on the entire surface through a 200-mesh screen, heated at 80 ° C. for 1 hour, and then subjected to a salt spray test at 35 ° C. for 48 hours. The coating was peeled off on the test stand, and the presence or absence of spread of iron powder in the lower aminoalkyd coating was examined. ○: No abnormality. Δ: Iron powder spread is recognized on 30% or less of the coated surface. X: Iron powder spread is recognized on 30% or more of the coated surface.

(* 10) According to JIS K7217. Gas generation method: tubular electric furnace quartz tube method. Sample amount 0.1g Temperature 650 ± 10 ° C Air flow rate 0.5l / min Gas collection method: HCN ... Solution absorption gas Quantitative method: Pyridine pyrazolone absorptiometry Detection limit 0.005mg / g

[0068]

EFFECTS OF THE INVENTION The peelable coating film obtained by using the composition of the present invention is chemically stable against light and heat.
It has excellent releasability from articles over time, and has an excellent function to protect from contamination by suspended solids and fallout in the atmosphere. The coating can be easily peeled off before handing over. Further, when the peeled film is incinerated, there is no possibility of generating harmful gas such as hydrogen cyanide gas, and there is no environmental problem.

Front page continued (72) Inventor Kenya Suzuki 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Naoki Miyata 4-1-1, East Hachiman, Hiratsuka, Kanagawa Within the corporation

Claims (1)

[Claims] 1. A carboxyl group-containing monomer containing (A) a (meth) acrylic acid ester as an essential component, and optionally other polymerizable monomers (excluding (meth) acrylonitrile) in combination. Of 5% by weight or less, glass transition temperature of 5 to 30 ° C., and weight average molecular weight of 20,000 or more, acrylic resin, (B) water repellent and (C) UV absorber Aqueous coating composition.