JP3141961B2 - Primer for easily peelable paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer for easily peelable paint containing a fluorine-containing copolymer resin and a method for producing a fluorine-containing copolymer resin contained in the primer.

[0002]

2. Description of the Related Art Generally, metal objects such as automobiles, other vehicles and aircraft, and components constituting them, painted or polished metal plates, and molded products such as metal, glass, and various plastics are handled and transported. During storage, storage, etc., the surfaces of the objects are scratched due to contact with each other or other objects, and contamination or discoloration due to dust, soot, metal powder, oil droplets, sea breeze, light, etc. in the air , Deterioration and the like may occur. For example, when the surface of the object is metal (especially iron-based), rust and the like are easily generated by the action of rainwater, moisture in the air, oxygen, sulfur compounds, etc. A great deal of labor and cost are required to remove the generated rust and the like. Therefore, in order to avoid the above problem by protecting and shielding the surface of the object in advance,
For the purpose of temporary protection and shielding of the surface of the object, and in some cases also for the purpose of coloring, organic solvent type,
Many easily peelable paints such as an aqueous resin emulsion type have been used.

[0003] However, a coating film provided on the surface of an object using an easily peelable paint may be easily removed if the object is left without being removed from the object for a long period of time or if the object having the coating film is left outdoors. Property, peel resistance increases,
There is a problem in that the coating film breaks when the coating film is peeled off, or a part of the coating film is broken and remains on the surface of the object without being peeled, resulting in a large decrease in peeling workability.

[0004] The above problem is that the surface of an object (hereinafter referred to as a base) to be protected, shielded, colored, or the like is rough, or the whole or part of the surface is a corner, a corner, or an uneven portion. ,
This is a particularly serious problem when it has a curved surface portion or when the surface material has an affinity for the coating film. In order to solve such a problem, it is conceivable to provide a coating of a primer in advance on the surface of the substrate to give easy peelability, and to form a coating of an easily peelable paint thereon.

On the other hand, as a primer, for example,
Japanese Patent Application Laid-Open No. 2-149784 discloses a method for preventing adhesion of a liquid epoxy resin in which a copolymer containing less than 90 to 80% by weight of a compound having a perfluoroalkyl group having 4 to 21 carbon atoms is dispersed in water or dissolved in an organic solvent. An agent composition is disclosed.

[0006] However, even if this liquid composition is used as a primer to form a coating film of the primer on the surface of the substrate, for example, the coating is applied to a rough surface such as a woven fabric made of spun yarn. The liquid composition becomes droplets of various sizes, and the liquid composition repels and adheres to large or inclined surfaces such as those of vehicles and aircraft. In any case, it is not possible to form a substantially uniform primer coating film having no defect on the entire desired surface of the substrate, for example, in some cases.

The copolymer contained in the composition is
It has the disadvantage that it dissolves in fluorinated solvents but is difficult to dissolve in common organic solvents.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a substrate coated with an easily peelable paint under severe conditions. For example, even after being left outdoors for a long period of time, the coating film does not cause spontaneous peeling, and the coating film has low peeling resistance, and can be easily peeled as a continuous film without breakage or tearing of the coating film. An object of the present invention is to provide a primer for forming an undercoat layer by applying the primer in advance to a surface of a substrate to be coated with an easily peelable paint, and a method for producing a copolymer resin to be contained in the primer. .

[0009]

As a result of various studies, the present inventors have found that a primer containing a copolymer resin of a specific composition obtained by a method of copolymerizing a specific monomer achieves the above object. The inventor has found that the present invention is to be carried out and completed the present invention.

That is, the first invention of the present invention relates to (a) 10 to 65% by weight of an acrylate or methacrylate unit having a fluoroalkyl group, and (b) a polyalkylene glycol acrylate or methacrylate unit. Is 5 to 40% by weight,
(C) a vinyl chloride and / or vinylidene chloride unit comprising 30 to 85% by weight, having a number average molecular weight of 10,000 to 10;
It is a primer for an easily peelable paint, which comprises 10,000 fluorocopolymer resins.

The second invention of the present invention relates to (a) an acrylic acid ester or methacrylic acid ester having a fluoroalkyl group, and (b) a polyalkylene glycol acrylate or a polyalkylene glycol methacrylate. The polymerization is started in a system containing 50% by weight and the total amount of (c) vinyl chloride and / or vinylidene chloride to be used, and the remaining amount of each of the components (a) and (b) is measured after the polymerization is started. A method for producing a fluorine-containing copolymer resin to be contained in the above-mentioned primer for easily peelable paint, characterized in that it is added to the above and polymerized.

Hereinafter, the present invention will be described in detail. A primer for easily peelable paint (hereinafter, referred to as a primer) according to the first invention of the present invention is to apply a primer to a surface of a substrate to be coated with the easily peelable paint in advance to form a primer coating film. Then, an easy-peelable paint is applied to the surface of the primer coating film to form an easy-peelable paint film, which is used for improving the releasability of the easy-peelable paint film.

The primer of the present invention contains a fluorinated copolymer resin (hereinafter referred to as a fluorinated resin), and usually further contains an organic solvent, water and the like as a medium at an arbitrary ratio.
The fluorine-containing resin contained in the primer is (a) an acrylic acid ester or a methacrylic acid ester having a fluoroalkyl group [hereinafter, both those with meta and those without meta are indicated with (meth)] Unit is 10 to 65
% By weight, preferably 20 to 55% by weight. When the content of the unit (a) is less than 10% by weight, the effect of lowering the peeling resistance of the easily peelable paint film cannot be sufficiently imparted to the primer coating film. No primer layer is obtained, and the solubility of the resin in common organic solvents is reduced.

The fluorine-containing resin contains (b) a polyalkylene glycol (meth) acrylate unit in an amount of 5 to 40% by weight, preferably 10 to 30% by weight. This (b)
If the unit content is less than 5% by weight, the flexibility of the primer coating film is low, it is difficult to dissolve in an organic solvent, and the peel resistance may be high. If it exceeds 40% by weight, drying of the primer is slow, and The film may be sticky, and when an easily peelable coating containing an organic solvent is applied on the coating, the primer coating is dissolved by the organic solvent, and the effect of lowering the peeling resistance is hindered. .

Further, the fluororesin contains (c) 30 to 85% by weight, preferably 40 to 60% by weight of vinyl chloride and / or vinylidene chloride units. When the unit (c) is less than 30% by weight, when an easily releasable paint containing an organic solvent is applied on the primer coating, the organic solvent dissolves the primer coating and reduces the peel resistance. Is inhibited. On the other hand, if this unit exceeds 85% by weight, the solubility of the fluorine-containing resin in an organic solvent is reduced, or the coating film becomes hard.

The number average molecular weight of the fluorine-containing resin contained in the primer of the present invention (by a method of converting the value measured by GPC into polystyrene) is 10,000 to 100,000, preferably 30,000 to 80,000. When the number average molecular weight is less than 10,000, the strength of the primer coating film is reduced, and sufficient peeling performance cannot be obtained when the coating film of the easily peelable paint formed thereon is peeled off. On the other hand, if it exceeds 100,000, the viscosity of the primer increases, and the workability of applying the primer decreases.

If desired, the fluorine-containing resin contained in the primer of the present invention may contain, in addition to the units (a), (b) and (c), 10% by weight or less based on the total amount of these units. A monomer unit may be contained as a constituent unit. Examples of the monomer used to introduce the above other monomer units include vinyl fluoride, vinylidene fluoride, alkyl (meth) acrylates, fatty acid vinyl esters, alkyl vinyl ethers, and monobasic monomers. Or polybasic polymerizable unsaturated carboxylic acids, polymerizable unsaturated dicarboxylic anhydrides and the like.

The primer of the present invention usually contains one or more organic solvents, water or both as a medium. Common organic solvents include ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone), esters (eg, methyl acetate, ethyl acetate, butyl acetate), and aromatics (eg, toluene, xylene). A system solvent (meta-xylene hexafluoride, trichlorotrifluoroethane, tetrachlorodifluoroethane, etc.) can be used alone or in combination with another organic solvent. Among the organic solvents, acetone, methyl ethyl ketone, toluene and ethyl acetate are preferred.

The proportion of the medium containing the primer depends on the desired properties of the primer, such as paintability, coatability,
It is arbitrarily selected depending on the drying property and the like.
It is about 00 parts by weight.

In the primer of the present invention, additives such as dyes, pigments, fillers, anti-sagging agents, flow improvers, and stabilizers (antioxidants, ultraviolet absorbers) are added as long as the effects are not impaired. Etc.), antifoaming agents, dispersing agents, rust inhibitors, surfactants, antistatic agents, insect repellents, fungicides, fungicides, plasticizers, and other various substances, and the amount of fluorine-containing It is about 10 parts by weight or less based on 100 parts by weight of the resin.

The primer of the present invention can be used, for example, in a dispersion such as a solution or emulsion containing a fluorine-containing resin,
It can be obtained by adding various substances as desired.

In order to form a primer coating by applying a primer to a substrate, any method can be used depending on the shape, size, material, desired thickness of the coating, properties of the primer to be used, etc. It is carried out by immersion, brushing, spraying, roller coating, or the like, by applying once or more than once to the partial or entire surface of the substrate on which the coating film of the easily peelable paint is to be formed. be able to. The applied primer may be dried by any method,
Heat drying may also be performed as heat treatment.

The amount of the primer applied to the surface of the substrate varies depending on the properties, shape and material of the surface of the substrate, but is usually about 3 to 150 g / m ^{2 on} a dry weight basis.

As the easily peelable paint applied on the coating film formed on the surface of the substrate using the primer of the present invention, any paint can be used, and typical examples thereof include polyvinyl acetal resin and vinyl chloride. -Vinyl acetate resin,
A solution type containing a main film-forming component comprising a vinyl acetate resin, a vinyl acetate-ethylene resin, an alkyl (meth) acrylate resin, a polyvinyl alcohol resin, a styrene-butadiene copolymer resin or an elastomer,
There are easily peelable paints such as a dispersion type. Among them, alcohol-containing solution type, water-dispersion type or aqueous solution type has a great effect on improving the releasability of the coating film obtained by using the easily releasable coating material, and particularly uses a polyvinyl acetal resin as a main film forming component. It is suitable when using an alcohol-containing solution type easily peelable paint.

By applying the primer of the present invention to the surface of an object to form a coating film, the surface of the object is imparted with properties such as antifouling property, water repellency and lubricity as well as easy peelability. Can be.

Next, a method for producing a fluororesin to be contained in the primer of the first invention, which is the second invention, will be described. The method for producing a fluororesin of the present invention is the above method of polymerizing a monomer in a system containing the above monomers (a), (b) and (c) and a polymerization initiator. Can be carried out by any method such as solution polymerization, emulsion polymerization, suspension polymerization and bulk polymerization, but solution polymerization or emulsion polymerization is preferred.

In the production method of the present invention, (a)
10 to 65 parts by weight of a (meth) acrylic acid ester monomer having a fluoroalkyl group, (b) 5 to 40 parts by weight of a polyalkylene glycol (meth) acrylate monomer, (c)
Vinyl chloride and / or vinylidene chloride monomer 30 to
Using 90 parts by weight, polymerization is started in a system containing the total amount of the component (c) to be used and 3 to 50% by weight of the amount of each of the components (a) and (b). b) A method in which the remaining amount of each component is added to the polymerization system after the initiation of the polymerization, and the remaining amounts of the components (a) and (b) are continuously added to the polymerization system after the initiation of the polymerization. Alternatively, it is preferable to add in a plurality of times.

In the present specification, the amount of each of the monomers (a) and (b) is 3 to
The polymerization is started when the addition of 50% by weight and the total amount of the monomer (c) to be used is completed and the temperature of the internal solution of the polymerization system reaches a desired temperature.

The monomer (a) used in the present invention is a (meth) acrylic ester having a fluoroalkyl group, and includes a monomer represented by the following general formula (I).

[0030]

## STR1 ## Formula (I) In the formula, R represents a hydrogen atom or a methyl group, and X represents the following groups (m and n each represent an integer of 1 to 11).

[0031]

## STR2 ## _{- (CH 2) m -C n} F 2n + 1 - (CH 2) m -O- (CF 2) 2 -O-C n F
_{2n + 1 - (CH 2)} m - (CF 2) 2n -H - (CH 2) m -O-CF (CF 3) 2 -CH (CF 3) 2 -CF (CF 3) 2 - (CH 2 ) _m -CFH-CF ₃

Preferred examples of the monomer (a) include:
2,2,2-trifluoroethyl (meth) acrylate,
Examples thereof include 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,3,4,4,4-hexafluorobutyl (meth) acrylate, and perfluorooctyl (meth) acrylate. The monomer (a) can be used alone or in combination of two or more.

The monomer (b) used in the present invention is a polyalkylene glycol (meth) acrylate, and the polyalkylene glycol portion of the monomer (b) contains oxyethylene units, oxypropylene units, oxybutylene units. What has two or more oxyalkylene units, such as a unit and an oxytetramethylene unit, two or more types is used. Examples of the monomer (b) include polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol / propylene glycol (meth) acrylate, polyethylene glycol / tetramethylene glycol (meth) acrylate, and the like. Among them, polypropylene glycol (meth) acrylate and polyethylene glycol / propylene glycol (meth) acrylate are preferred.

As the monomer (b), those having 2 to 6 carbon atoms in the oxyalkylene unit and an average number of repeating oxyalkylene units in the polyalkylene glycol part of 3 to 20 are usually used. Further, the monomer (b) can be used alone or in combination of two or more.

As the monomer (c), vinyl chloride and vinylidene chloride may be used alone or in combination.

In the production method of the present invention, in addition to the monomers (a), (b) and (c), if desired, one or more other monomers copolymerizable with these monomers can be used. Polymerization can be carried out by coexisting in two or more polymerization systems.

In order for the above-mentioned other copolymerizable monomer to coexist in the polymerization system, a method of adding the whole amount to be used before or after the initiation of polymerization to the polymerization system, and a part of the used amount Can be added to the polymerization system before the start of the polymerization, and then the remaining amount is added to the polymerization system after the start of the polymerization. The amount of the other radical copolymerizable monomer used may be any amount, but is usually 10% by weight of the total amount of the monomers (a), (b) and (c) used.
Below.

The polymerization initiator used in the polymerization reaction can be used singly or in combination of two or more. Examples thereof include organic peroxides such as peroxyesters and diacyl peroxides, and 2,2 'azobisisopropane. Butyronitrile, 2,2
'-Azobis- (2,4-dimethylvaleronitrile),
Examples include azo compounds such as 2,2'-azobis- (4-methoxy-2,4-dimethylvaleronitrile), and inorganic peroxides such as potassium persulfate, sodium persulfate, ammonium persulfate, and hydrogen peroxide.

In the polymerization reaction, if necessary, one or more media are selected from an organic solvent, water and the like based on the polymerization system. As the organic solvent,
Examples include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl acetate, ethyl acetate and butyl acetate, aromatics such as toluene and xylene, and alcohols such as methanol, ethanol and isopropanol. , Methyl ethyl ketone, toluene, ethyl acetate and the like.

In emulsion polymerization and suspension polymerization, known substances such as various surfactants and high molecular substances (partially saponified polyvinyl acetate, polyvinyl alcohol, alkyl celluloses, etc.) are used as emulsion dispersion stabilizers. Usually, it is used after being appropriately selected. The polymerization conditions are not particularly limited, but the polymerization temperature is preferably in the range of 30 to 80C.

The average molecular weight of the obtained copolymer resin may be determined, if desired, by a chain transfer agent (compounds containing sulfur atoms such as mercaptans and mercapto alcohols, halogens such as carbon tetrachloride, trichloroethylene and carbon tetrabromide). Compound, aldehyde compound, etc.), the solvent used in the polymerization system, the content of the polymerization system solvent, the polymerization temperature and the selection of the polymerization system.

As the polymerization apparatus, for example, a polymerization apparatus used for producing a vinyl chloride resin can be used. When a monomer, a polymerization initiator, a medium and the like are added to the polymerization system under pressure, a high-pressure pump or the like is used. Can be added.

The fluorine-containing resin obtained by the polymerization is optionally subjected to removal of unreacted monomers, precipitation, liquoring, washing, filtration,
It can be obtained as a resin separated through drying or the like. In addition, the solution or emulsion resin obtained by solution polymerization or emulsion polymerization is, if desired, to remove unpolymerized monomers, particularly vinyl chloride, and to add and blend the above-mentioned various additives thereto, to form a solution. A primer in the form of an emulsion or an emulsion can be obtained.

[0044]

The present invention will be described below with reference to examples and comparative examples. Hereinafter, both “%” and “parts” are based on weight.

Example 1 A 5-liter stainless steel autoclave equipped with a stirrer in which oxygen inside was removed by replacing with nitrogen was charged with 7 parts of perfluorooctyl methacrylate, 2 parts of polypropylene glycol monomethacrylate (repeating number of oxypropylene units: 12), 32 parts of ethyl acetate, 32 parts of toluene, 0.5 part of benzoyl peroxide and 60 parts of vinyl chloride were charged, and polymerization was started at a temperature of 65 ° C. with stirring.

Over a period of 17 hours after the start of the polymerization, 28 parts of perfluorooctyl methacrylate, 8 parts of polypropylene glycol monomethacrylate, 18 parts of ethyl acetate and 18 parts of toluene were continuously added to the polymerization system at 25 ° C. for 25 hours. Polymerization was performed. The nonvolatile content of the obtained reaction solution was about 50%. The viscosity of a fluorine-containing resin solution having a nonvolatile content of 20% obtained by adding an equal weight mixture of ethyl acetate and toluene to this reaction solution (using a B-type viscometer, 25
° C) was 150 cps.

The composition (measured by NMR) of the obtained copolymer resin was 35 perfluorooctyl methacrylate units.
%, Polypropylene glycol monomethacrylate unit 10%, and vinyl chloride unit 55%. The number average molecular weight (by GPC method) of the fluororesin is 45.
000. Next, the fluororesin obtained above was added to 2
An evaluation test was performed using a liquid containing 0% as a primer for easily peelable paint. Table 3 shows the results.

Examples 2 to 16 In the same manner as in Example 1 except that the polymerization conditions were changed as shown in Tables 1 and 2, 2 of the fluorine-containing resin having the properties shown in Tables 1 and 2 were used.
A 0% solution was obtained. Next, an evaluation test was performed using the 20% liquid obtained above as a primer. The results are shown in Tables 3 and 4.
Shown in

Example 17 Example 1 was repeated except that 2 parts of t-dodecyl mercaptan as a chain transfer agent was added to the polymerization reaction system to initiate polymerization.
In the same manner as described above, a polymerization reaction solution containing a fluorine-containing resin having the properties described in Table 2 was obtained. An equal weight mixture of ethyl acetate and toluene was added to the reaction solution to give a nonvolatile content of 20%.
% Liquid was obtained. Next, the nonvolatile content concentration of 20% obtained above
An evaluation test was carried out using this liquid as a primer for easily peelable paint. Table 4 shows the results.

Example 18 The procedure of Example 1 was repeated except that the polymerization temperature was 40 ° C. and 0.5 parts of diisopropyl peroxydicarbonate was used instead of 0.5 parts of benzoyl peroxide. A reaction solution containing a fluorine-containing resin having the properties described below was obtained. An equal weight mixture of ethyl acetate and toluene was added to this reaction solution to obtain a solution having a nonvolatile content of 20%.
Next, an evaluation test was performed using the liquid having a nonvolatile content of 20% obtained above as a primer for easily peelable paint. Table 4 shows the results.

Example 19 Deionized water (64.8) containing 0.6 parts of methylcellulose and 0.2 parts of sodium lauryl sulfate dissolved in a 5-liter stainless steel autoclave equipped with a stirrer in which oxygen inside was removed by purging with nitrogen. Parts, 7 parts of perfluorooctyl methacrylate, 2 parts of polypropylene glycol monomethacrylate (repeating number of oxypropylene unit: 12),
Charge 0.5 part of sodium persulfate and 60 parts of vinyl chloride,
Under stirring, polymerization was started at a temperature of 60 ° C.

Over 17 hours after the start of the polymerization, 28 parts of perfluorooctyl methacrylate, 8 parts of polypropylene glycol monomethacrylate and 36 parts of deionized water were added.
Polymerization was carried out at 65 ° C. for 25 hours while continuously adding to the polymerization system. The resulting emulsion had a nonvolatile content of about 50%. The emulsion was diluted with deionized water to a non-volatile content of 20%. The viscosity at 25 ° C. of this fluorine-containing resin emulsion is 20
cps.

Table 2 shows the composition and number average molecular weight of the copolymer resin contained in the obtained emulsion. Then
An evaluation test was performed using the emulsion containing 20% of the fluororesin obtained above as a primer. Table 4 shows the results.

Examples 20 to 22 and Comparative Examples 1 to 7 A reaction solution containing a fluorine-containing resin having the properties listed in Table 2 in the same manner as in Example 1 except that the polymerization conditions were as shown in Table 2. I got An equal weight mixture of ethyl acetate and toluene was added to this reaction solution to obtain a solution having a nonvolatile content of 20%. Next, an evaluation test was performed using the liquid having a nonvolatile content of 20% obtained above as a primer for easily peelable paint. Table 4 shows the results.

Comparative Example 8 Measurement was carried out without using a primer in accordance with the items iii) and iv) of the evaluation test method of the primer. Table 4 shows the results.

Evaluation Test Method of Primer i) Viscosity (unit: cps / 25 ° C.) The viscosity of the primer at 25 ° C. was measured with a B-type rotational viscometer.

Ii) Solution appearance Primer (25 ° C.) was placed in a transparent glass container of about 300 ml, and the entire gelling, insoluble matter, aggregates, etc. were visually observed. The solution appearance was normal. When the primer was in the form of an emulsion, in addition to the observation in the above-described container, the observation in a state of being applied to a transparent glass plate was also performed. In addition, the evaluation test of the other physical properties of the primer was not performed for the primer whose solution appearance was not normal.

Iii) Peeling resistance (unit: g / cm) iii) -1 Thick cotton fabric (70 × 150 mm, warp 16 / cm, weft 13 / cm, woven fabric density, weight per unit area) Is about 0.04 g / cm ² and has a rough surface, and is fixed on a steel plate having a thickness of 1 mm so as not to be wrinkled. Next, the entire surface of the fixed thick cloth is brushed with a primer so that the dry coating amount is about 30 to 40 g / m ^2, and then is applied in an atmosphere at 23 ° C. for 3 hours (when the primer is an emulsion). Is 6 at 23 ° C
Time) air dried. Next, on the coating surface of this primer, a polyvinyl butyral resin (PVB) -based easy-peeling paint having the following composition is applied by brush so that the coating thickness when dried is about 150 μm, and the coating is applied in an atmosphere at 23 ° C. for 48 hours. Let dry for hours. As described above, a sample for peeling resistance measurement was obtained in which a primer coating was formed on the surface of the thick cloth fixed to the steel plate and a PVB-based easily peelable coating was formed thereon.

Composition of PVB-based easily peelable paint PVB resin 100 parts (average degree of polymerization: 830, vinyl butyral part: 77.7%) Ethanol 330 parts Tricresyl phosphate 50 parts Lecithin 2.2 parts Antioxidant 1 part ( Ciba-Geigy, product name Irganox 1010)

Iii) -2 Peeling resistance 48 hours after application of paint (unit: g / cm) The drag at 180 ° peeling of the easily peelable paint film from the sample obtained in iii) -1 was 23. JI under an atmosphere of ℃
It was measured according to SK 1708.

Iii) -3 Peeling resistance after treatment with a weather meter for 400 hours (unit: g / cm) A sunshine super long life weather meter (Suga) was applied to the coated surface of the sample obtained in iii) -1. Using a test machine, model number WEL-SUN-HCH), a sample that was subjected to a repetitive treatment (surface temperature of the surface to be treated of 63 ° C.) for 400 hours after irradiation with carbon arc light for 120 minutes and water spraying for 18 minutes. .

The resistance at 180 ° peeling of the easily peelable paint film formed on one side of the sample subjected to the above treatment was measured in an atmosphere of 23 ° C. in accordance with JIS K 1708, and obtained. The value obtained was defined as the coating film peeling resistance (g / cm) after treatment with a weather meter for 400 hours.

Iv) Peeling workability (a) When the substrate is a steel plate A primer is applied to one entire surface of a surface degreased SPCC steel plate (30 × 30 cm), and a dry coating amount is about 30 to 40 g / m ^2.
After brush-coating, the film is left to dry in an atmosphere at 23 ° C. for 3 hours (6 hours when the primer is an emulsion). Next, the PVB-based easy-peeling paint or the solution-type easy-peelable paint of vinyl chloride-vinyl acetate-based copolymer resin (VC-VAC) [Kansai Paint Co., Ltd.] Product name: Strip Paint Green, resin content 21%, ketone-based solvent
7%, others (plasticizers, additives, coloring agents) 7.3%],
Or vinyl acetate-ethylene copolymer resin (EV
The aqueous emulsion of (A) (vinyl acetate 82%, ethylene 18%, nonvolatile content: about 55%) was brush-coated to form a coating film (dry thickness: about 150 μm). This steel plate
It was air-dried in an atmosphere of 3 ° C. for 48 hours.

After standing and drying, 0.5 cm from each outer edge of the steel plate
A linear cut is made on the inner coating film to reach the steel plate surface with a sharp blade in parallel with each outer edge. Next, the inner coating film (approximately 29.
(5 × 29.5 cm) is peeled away from the steel sheet at once by hand, and the peeling workability is evaluated according to the criteria described later.

(B) When the substrate is a thick cloth: 50 × 50 cm thick cotton cloth (having a woven fabric density of 16 warps / cm and 13 wefts / cm, and weighing about 0.04 g / unit area) cm ^2, a cotton canvas) having a rough surface, on the thickness of 12mm of a flat plate, fixed stretched to prevent wrinkles. Next, the entire surface of the fixed thick cloth is brush-coated with a primer so that the dry coating amount is about 30 to 40 g / m ^2, and then, for 3 hours in an atmosphere at 23 ° C. (when the primer is an emulsion, , 2
Air dried at 3 ° C for 6 hours).

On the surface of the thick cloth coated with the primer,
Four thin copper wires of about 60 cm in length are stretched in close contact with each other so as to form approximately 30 cm × 30 cm squares. The surface of the entire thick cloth having four copper wires adhered to the surface is coated with the same PVB paint or VC-
A VAC paint or an EVA emulsion was applied twice by a spray method to form a coating film. 23 ℃
Was air-dried for 48 hours in the atmosphere.

After leaving to dry, one end of each of the four copper wires is slowly pulled up one by one toward the coating surface of the paint while holding both sides of the coating surface along the copper wire with a straight ruler. In this way, the coating film on the part where the copper wire was located is cut off,
A coating film cut into an approximately square of 0 × 30 cm was obtained. Next, the inner coating film (about 30 cm × 30 c
m) was peeled off from the thick cloth at once by hand, and the peeling workability was evaluated according to the following criteria.

Evaluation criteria for peeling workability (common to the above (a) and (b)) A: The film was not spontaneously peeled during standing, and could be peeled without a large resistance as a continuous film as a whole. …: Although there is a slight resistance to peeling or spontaneous peeling is partially observed, the whole film can be peeled as a continuous film. ×: The film cannot be peeled off, the film is broken and the whole film cannot be peeled off as a continuous film, a part of the film is broken and remains without being peeled off, or more than half of the coating film area is naturally peeled off during standing. I have.

V) Stickiness of Primer Coating Surface The primer was applied in the same manner as in iii) -1 above,
The feel when touching the coated surface of the dried primer with a finger is shown by the following criteria.

Evaluation criteria for stickiness of primer coating surface A: Smooth feeling without stickiness. ○: Slightly sticky, but felt slippery. ×: There is stickiness.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

Description of abbreviations in Tables 1 and 2 Monomer PFOMA: Perfluorooctyl methacrylate PFOA: Perfluorooctyl acrylate TFEMA: 2,2,2-Trifluoroethyl methacrylate PPGMA-1: Polypropylene glycol methacrylate, n = 12 PPGMA-2: Polypropylene glycol methacrylate, n = 6 PPGA : Polypropylene glycol acrylate, n
= 12 PEGPPGMA: polyethylene glycol / polypropylene glycol methacrylate, n = 10 oxyethylene units / oxypropylene units = 7/3
(Molar ratio) PGMA: propylene glycol methacrylate, n =
1

2. Addition method of monomer to be added after initiation of polymerization: Continuous addition over 17 hours after initiation of polymerization. : The first addition was carried out 4 hours after the initiation of the polymerization, and thereafter, every 4 hours, and added in four equal portions by weight in total.

[0077]

The primer of the present invention greatly improves the ease of peeling of the easily peelable paint film formed on the paint film. Even if the surface of the substrate provided with the primer coating film and the easily peelable paint film has a low releasability such as a rough surface, the substrate further provided with the coating film is exposed to severe conditions for a long period of time. Even after this, the excellent effect of exhibiting high peeling workability of the easily peelable paint film is exhibited. Further, by the production method of the present invention, it is possible to easily obtain a fluorine-containing copolymer resin which exhibits excellent effects when used as the primer.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akio Nishijima 1135 Nakamura, Shibukawa-shi, Gunma Denki Kagaku Kogyo Co., Ltd. Inside Shibukawa Plant (56) References JP-A-51-2738 (JP, A) 432 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 5/20

Claims (3)

(57) [Claims] (1) When the (a) acrylate or methacrylate unit having a fluoroalkyl group has 10 units
(B) 5 to 40% by weight of a polyalkylene glycol acrylate or polyalkylene glycol methacrylate unit, and (c) 30 to 85% by weight of a vinyl chloride and / or vinylidene chloride unit. A primer for easily peelable paint, comprising 10,000 to 100,000 fluorine-containing copolymer resins. 2. An amount of (a) an acrylate or methacrylate having a fluoroalkyl group, and (b) a polyalkylene glycol acrylate or a polyalkylene glycol methacrylate.
The polymerization is started in a system containing 50% by weight and the total amount of (c) vinyl chloride and / or vinylidene chloride to be used, and the remaining amount of each of the components (a) and (b) is measured after the polymerization is started. The method for producing a fluorine-containing copolymer resin according to claim 1, wherein the polymerization is carried out by adding the compound to a polymer. 3. The fluorinated copolymer according to claim 2, wherein the remaining amount of each of the components (a) and (b) is added to the polymerization system continuously or divided into a plurality of times after the initiation of the polymerization and the polymerization is carried out. Method of manufacturing resin.