JPH02124986A - Acid-setting coating composition for polyolefin resin - Google Patents

Abstract

PURPOSE:To obtain the title composition which provides a polyolefin resin with a coating film excellent in adhesiveness, weatherability, moisture resistance, appearance, etc., and has no pot life by mixing a hydroxylated chlorinated polyolefin, an alkyl-etherified amino resin, and an acid catalyst. CONSTITUTION:The title composition is prepared by mixing 95-10wt.% hydroxylated chlorinated polyolefin (A) (e.g., a polyolefin having a chlorine content of 5-50wt.%), 5-90wt.% alkyl-etherified amino resin (B) (e.g., an alkyl- etherified urea resin), and an acid catalyst (C) (e.g., p-toluenesulfonic acid). This composition is used for protection or decoration of polyolefin resin. It can be used for top coating or undercoating of the sheet, film, and molding of said resin to provide a coating film excellent in adhesiveness, weatherability, moisture resistance, solvent resistance, appearance, etc. It has no pot life and can be handled as a one-pack type.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to polyolefin resins, such as polypropylene homopolymers, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, etc., used for protection or cosmetic purposes. More specifically, the coating composition can be applied as a top coat or undercoat to polyolefin resin sheets, films, and molded articles to provide a coating film with excellent adhesion, weather resistance, moisture resistance, solvent resistance, appearance, etc. The present invention relates to an acid-curable coating composition for polyolefin resins.

[Conventional technology]

Polyolefin resins have excellent properties such as chemical resistance, ozone resistance, heat resistance, and good electrical properties, and because they are lightweight and inexpensive, they are used in a wide range of industrial materials, including home appliances and automobile parts. It is one of the materials whose demand is most expected to grow in the future.

However, despite having these characteristics, when it comes to automobile parts, for example, various plastics are being used to reduce weight from the perspective of energy conservation, and the use of polyolefin resins is increasing year by year. remains in some parts. One of the reasons preventing its widespread use is that polyolefin resins are nonpolar and crystalline, making them difficult to paint or adhere to. Printing or adhesion to polyolefin resin is
Conventionally, adhesion has been improved by treatments such as corona discharge, but these methods have the drawback of not being able to uniformly treat molded articles with complex surfaces.

Therefore, various brimer compositions that have good adhesion to polyolefin resins have been proposed as methods for coating without these pretreatments.

For example, Special Publication No. 49-18089, Special Publication No. 49-52
Examples include the primer composition shown in No. 14, which comprises a cyclized rubber, an aromatic petroleum resin, an oil-soluble phenol resin, a coumaron indene resin, and a chlorinated polyolefin. However, even if these adhesives have good adhesion to polyolefin resins, they may have insufficient adhesion to top coats, or even if they show good adhesion to both polyolefin resins and top coats, they are solvent resistant. It has the disadvantage of poor performance. Particularly in recent years, coating compositions that have stronger adhesion and weather resistance as well as gasoline resistance have been required for painted objects used outdoors such as on automobiles and motorcycles. Regarding these, please refer to JP-A-56-50
No. 971, a copolymer of a chlorinated polyolefin, a basic nitrogen-containing acrylic monomer, and other acrylic monomers is blended with an epoxy resin as a curing agent, and JP-A-59 No.-75958, JP-A-60
-223831, in which tertiary amines are added to carboxylated chlorinated polyolefin as an accelerator, and epoxy resin is used as a curing agent, and JP-A-62-18434, , a copolymerization of a chlorinated polydiene, a chlorinated polyolefin, and a hydroxyl group-containing acrylic monomer and a polyisocyanate as a curing agent have been proposed. These are certainly excellent in adhesion to polyolefin resins, solvent resistance, and other physical properties, but since they are two-component curing compositions in which the main ingredient and curing agent are mixed immediately before use, the curing agent It has a so-called pot life, which is the period of time from when it is added until the curing reaction progresses to a certain extent and coating becomes difficult, and it has the disadvantage that it is subject to significant restrictions on working time.

[Problem to be solved by the invention]

The drawback of a composition having a pot life is that it not only imposes a major restriction on working time, but also, for example, when painting or printing is completed, the remaining composition must be discarded before it hardens, and the remaining composition must be disposed of before it hardens. Printing equipment and lights
It becomes necessary to thoroughly clean the container.

The present invention provides excellent adhesion to polyolefin resins.
In addition to weather resistance, moisture resistance, appearance, etc., it has excellent solvent resistance, and is a new product that can be handled as a one-component composition and has no pot life, improving the drawbacks of two-component curing compositions. A useful acid-curable coating composition is provided.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present inventors developed a method in which a resin containing a hydroxyl group and an alkyl etherified amino resin do not react at room temperature in the presence of an acidic catalyst, but are heated to about 60°C or higher. Focusing on the fact that the reaction proceeds and forms a cured resin, we use 5 to 90% by weight of alkyl etherified amino resin to 95 to 10% by weight of hydroxyl group-containing chlorinated polyolefin that has good adhesion to polyolefin resin. The acid-curing coating composition, which consists of an acid catalyst and an acidic catalyst, not only exhibits excellent physical properties such as adhesion, weather resistance, moisture resistance, appearance, and solvent resistance to polyolefin resins, but also exhibits excellent physical properties such as adhesion, weather resistance, moisture resistance, appearance, and solvent resistance. It was discovered that the curing reaction does not proceed as long as the material is handled, and there is no pot life, leading to the present invention.

The hydroxyl group-containing chlorinated polyolefin used in the present invention is a polyolefin resin, such as crystalline polypropylene, amorphous polypropylene, polybutene-1, polybentene-1,4-methylpentene-1, low density or high density polyethylene, ethylene- It is obtained by dispersing or dissolving propylene copolymers alone or in combination of two or more in a chlorinated solvent, and then blowing chlorine gas at a temperature of 50 to 120°C in the presence of a radical generator or under irradiation with ultraviolet rays. The resulting chlorinated polyolefin is further reacted with an acrylic monomer containing a hydroxyl group, in whole or in part, in the presence of a radical generator. In addition, in order to smoothly carry out the graft reaction between the chlorinated polyolefin and the acrylic monomer, at least one selected from air, oxygen, and boson is simultaneously blown into the polyolefin to oxidize and modify the chlorinated polyolefin. Such a formulation is desirable for synthesizing the product of the present invention.

A method for producing such a chlorinated polyolefin containing a hydroxyl group is disclosed in Japanese Patent Application Laid-Open No. 1028-1987, which was already proposed by the applicant.
92 and Japanese Patent Publication No. 51-24318.

In addition, the hydroxyl group-containing chlorinated polyolefin modified with an unsaturated polycarboxylic acid or its acid anhydride used as the hydroxyl group-containing chlorinated polyolefin in the present invention can be produced by hot-melting the raw material polyolefin resin described above, and then producing it in a batch process. Alternatively, in a continuous method, after modifying with an unsaturated polycarboxylic acid or its acid anhydride in the presence of a radical generator, chlorination is performed in a chlorinated solvent in the same manner as above, and further in the presence of a radical generator, all or One part is obtained by reacting with an acrylic monomer containing a hydroxyl group.

Examples of the unsaturated polycarboxylic acid or its acid anhydride used in the modification reaction include maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, fumaric acid, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid,
Examples include aconitic anhydride. In addition, examples of radical generators used in the modification reaction include di-1e+1-butyl peroxide, terl-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide,
These include peroxides such as tell-butyl peroxide benzoate, methyl ethyl ketone peroxide, and di-ter+-butyl ciber phthalate, and azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

Examples of the acrylic monomer containing a hydroxyl group used in the present invention include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxylpropyl acrylate, and 2-hydroxylpropyl methacrylate. Other acrylic monomers include, for example, acrylic acid, methyl acrylate,
Ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, glycidyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 1-butyl methacrylate , 2-ethylhexyl methacrylate, lauryl methacrylate, grecidyl methacrylate, and the like.

The alkyl etherified amino resin used in the present invention is obtained by reacting an amino compound such as urea, melamine, or benzoguanamine with formaldehyde to form methylol, and then etherifying it with a lower alcohol such as methanol or butanol.

For example, n-butyl etherified urea resin, isobutyl etherified urea resin, methyl etherified melamine resin, n-butyl etherified urea resin,
-butyl etherified melamine resin, n-butyl etherified benzoguanamine resin, etc.

The oxygen catalyst used in the present invention is one that promotes the reaction between the hydroxyl group-containing chlorinated polyolefin and the alkyl etherified amino resin, and any catalyst that exhibits acidity such as hydrochloric acid, nitric acid, phosphoric acid, and organic acids can be used.

For example, alcoholic solutions of hydrochloric acid, salts of strong acids such as ammonium chloride, phosphoric acid esters such as monobutyl phosphate, organic sulfonic acids such as p-toluenesulfonic acid, etc. may be used alone or in combination of two or more. Can be used.

The resin component of the composition of the present invention is the aforementioned hydroxyl group-containing chlorinated polyolefin and alkyl etherified amino resin, and if the proportion of the alkyl etherified amino resin is less than 5% by weight, the crosslinking density will be low, so that sufficient performance cannot be achieved. A coating film cannot be obtained.

Moreover, if it exceeds 90% by weight, the drying properties of the coating film and the adhesion to the polyolefin resin will deteriorate. Therefore, the proportion of the alkyl etherified amino resin in the resin content is usually 5 to 90% by weight, preferably 10 to 80% by weight.

The chlorine content of the hydroxyl group-containing chlorinated polyolefin used in the present invention can range from 5 to 50% by weight, preferably from 10 to 45% by weight. If the chlorine content is too low, the solution condition will be poor, and if the chlorine content is too high, the adhesion to the polyolefin resin will be poor.

The advantage of modifying the hydroxyl group-containing chlorinated polyolefin used in the present invention with an unsaturated polycarboxylic acid or its acid anhydride is that when the composition is used as an undercoat, the adhesion with the topcoat is improved. be done.

Further, the amount of acid catalyst used to promote the reaction between the hydroxyl group-containing chlorinated polyolefin and the alkyl etherified amino resin can be reduced. In this case, the saponification value of the polyolefin modified with unsaturated polycarboxylic acid or its acid anhydride is at least 6, preferably 1.
1) to 60. If the saponification value is too low, the adhesion to the top coat will not be improved much, and the acid catalyst will have little effect. Furthermore, if the saponification value is too high, the adhesion to the polyolefin resin will be poor, and the moisture resistance and water resistance of the coating film will be reduced.

The solvent used in the composition of the present invention is most preferably a mixed solvent mainly consisting of alcohols and aromatic hydrocarbon solvents.

Alcohols include methanol, ethanol, isopropanol, and butanol, and aromatic hydrocarbon solvents include toluene and xylene. In addition, saturated cyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane are also good solvents.

It is also possible to use a mixture of ester solvents, ketone solvents, etc.

[For production]

The present invention is characterized in that an acid-curing coating composition comprising a hydroxyl group-containing chlorinated polyolefin, an alkyl etherified amino resin, and an acidic catalyst can be applied to polyolefin resins that are inherently difficult to adhere to;
Disadvantages of two-component curing compositions, which can be handled as a liquid, include: (1) Significant restrictions are placed on working time due to the fact that the reaction proceeds from the time the main ingredient and curing agent are mixed; (2
) At the end of painting or printing, the remaining composition must be disposed of. (3) It is necessary to thoroughly clean the equipment and lines used. It is possible to solve problems related to work, resource saving, and energy saving.

The composition according to the present invention may be used as a coating as it is, but it can also be used as a paint or ink by adding pigments and other additives.

Although the composition alone exhibits well-balanced physical properties of the coating film, it is possible to further add cyclized rubber, petroleum resin, acrylic resin, alkyd resin, etc., if necessary.

The composition according to the present invention is applied to a polyolefin resin sheet, film, or molded article, air-dried at room temperature, and then baked at a temperature of 60°C or higher, preferably 80°C or higher, to give a one-coat finish. A coating film is obtained. The resulting coating film has excellent physical properties such as adhesion, weather resistance, water resistance, moisture resistance, and solvent resistance, and is suitable for use not only on polyolefin resins but also on other plastics, wood, steel, concrete, and other base materials. It can also be applied to

Furthermore, the composition according to the present invention can also be used as an undercoat paint for polyolefin resin. Existing paints such as melamine resin paints, epoxy resin paints, acrylic resin paints, urethane resin paints, alkyd resin paints, etc. are suitable as the top coat used for this removal. Compared to paint films, it has superior gasoline resistance, water resistance, moisture resistance, chemical resistance, bending resistance, impact resistance, etc., and exhibits strong adhesion to both base materials and top coats.

[Examples and effects of the invention]

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Production Example-1 3 kg of isotactic polypropylene with a melt flow index of 1.5 measured according to JIS-675 g was uniformly dissolved in carbon tetrachloride 701 under pressure.
Chlorination is performed while irradiating ultraviolet rays at a temperature of 00 to 110°C, and when the degree of chlorination reaches approximately 10%, a mixed gas with a chlorine/oxygen volume ratio of 4515.5 is blown in to oxidize the chlorine while performing oxidation treatment. Chlorination was carried out until the content was 27% by weight.

After the reaction was completed, carbon tetrachloride as a solvent was distilled off using an evaporator and replaced with toluene to obtain a toluene solution with a non-volatile content of 20% by weight. Next, 1000 g of the toluene solution was placed in a Mitsuro flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the solvent and monomer, and the mixture was heated to 70 to 80°C.
It was kept warm. Add 2g of benzoyl peroxide,
After purging with nitrogen gas while stirring for about 30 minutes, 30 g of 2-hydroxylethyl methacrylate was added sequentially from the dropping funnel over about 2 hours, and graft polymerization was carried out for about 3 hours.
Hydroxyl group-containing chlorinated polypropylene was obtained.

Production Example-2 500 g of isotactic polypropylene with a melt viscosity of approximately 26QOCPS at 180°C was placed in a Mitsuro flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, and the mixture was kept at a constant temperature of 180°C. Completely melted in a dripping oil bath. Replace nitrogen in the flask by approximately 1
After 0 minutes, add 20 g of anhydrous malein while stirring.
was added over a period of about 5 minutes, and then 2 g of di-1e+l-butyl peroxide was dissolved in 10 ml of hebutane, and the solution was added through a dropping funnel over a period of about 30 minutes. At this time, the system has 1
The temperature was maintained at 80° C., and the reaction was continued for about 1 hour, after which unreacted maleic anhydride was removed over about 30 minutes while reducing the pressure inside the flask with an aspirator. The saponification number of this product was 26. Next, 500 g of this product was put into a glass-lined reaction vessel, 101 carbon tetroxide was added, and after fully melting at 110°C under a pressure of 2 kg/al, chlorine-containing Chlorine gas was blown in until the amount was 25% by weight. After the reaction was completed, the solvent carbon tetrachloride was distilled off using an evaporator and replaced with toluene to obtain a 20% by weight toluene solution of chlorinated polypropylene modified with maleic anhydride.

Production Example-3 1,000 g of the maleic anhydride-modified chlorinated polypropylene (20% by weight toluene solution) obtained in Production Example-2 was placed in a Mitsuro flask equipped with the same equipment as Production Example-1, and 2 g of benzoyl peroxide 1 2-hydroxyl methacrylate was added. Graft polymerization was performed using 40 g of ethyl in the same manner as in Production Example 1 to obtain a hydroxyl group-containing chlorinated polypropylene modified with maleic anhydride.

Production Example-4 1,000 g of the maleic anhydride-modified chlorinated polypropylene (20% by weight toluene solution) obtained in Production Example-2 was placed in a Mitsuro flask equipped with the same equipment as Production Example-1, and 2 g of benzoyl peroxide 1 2-hydroxyl methacrylate was added. Graft polymerization was carried out in the same manner as in Production Example 1 using 20 g of ethyl and 20 g of methyl methacrylate to obtain a hydroxyl group-containing chlorinated polypropylene modified with maleic anhydride.

Example-1 100 parts by weight of the hydroxyl group-containing chlorinated polyolefin obtained in Production Example-1 and Super Beckamine L-127-6
0 (manufactured by Dainippon Ink Chemical Co., Ltd., n-butyl etherified melamine resin, nonvolatile content 60%) 16 parts by weight and P- as an acid catalyst) Luenesulfonic acid/36% hydrochloric acid/isopropanol = IO/Ill/80 Mix 20 parts by weight of the solution (weight ratio), put it in a completely sealed container, and add 40 parts by weight.
It was stored in an atmosphere at ℃ and the viscosity change over time was observed. The results are shown in Table-1.

Example-2 Hydroxyl group-containing chlorinated polypropylene 1 modified with maleic anhydride obtained in Production Example-3 [10 parts by weight] and Melan 220 (manufactured by Hitachi Chemical Co., Ltd., n-butyl etherified melamine resin, non-volatile content 70%) ) and 10 parts by weight of the acid catalyst of Example-1 were mixed and stored in the same manner as in Example-1, and changes in viscosity over time were observed. Display the results -
Shown in 1.

Example-3 100 parts by weight of the hydroxyl group-containing chlorinated polypropylene modified with maleic anhydride obtained in Production Example-4 and Melan 1
1 (manufactured by Hitachi Chemical Co., Ltd., butyl etherified urea resin, non-volatile content 60%) and 10 parts by weight of the acid catalyst of Example-1 were mixed, stored in the same manner as in Example-1, and aged. The viscosity change was observed. The results are shown in Table-1.

Comparative Example-1 100 parts by weight of maleic anhydride-modified chlorinated polypropylene obtained in Production Example-2 and Epo)-Y)l-3 as a curing agent
(10 (manufactured by Tobu Kasei Co., Ltd., trifunctional epoxy resin)
2 parts by weight and DBU as a tertiary amine catalyst [manufactured by Sanapuchi Co., Ltd., 1,8-diaza-bicyclo(5,4
, Q) Undecene-7] was mixed and stored in the same manner as in Example-1, and the change in viscosity over time was observed.

The results are shown in Table-1.

Comparative Example-2 100 parts by weight of the carboxyl group-containing chlorinated polypropylene modified with maleic anhydride obtained in Production Example-2 was mixed with 6 parts by weight of Sumidur N-3200 (manufactured by Sumitomo Bayer Urethane Co., Ltd., polyisocyanate) as a curing agent. The sample was stored in the same manner as in Example 1, and changes in viscosity over time were observed. The results are shown in Table-1.

Table - Viscosity measurement over time of festivals stored at 140℃ is B
A type viscometer was used. The measurement temperature is 25°C. The units in the table are centiboise (C, P). As seen from Table 1, the acid-curing coating compositions of Examples 1, 2, and 3 can be stored at 40°C for one month. Hardly any thickening of the fest was observed, but the two-component curing compositions using the curing agents of Comparative Examples 1 and 2 thickened over time and reached gelation within a few days, making work difficult. Become. This shows that the product of the present invention is very advantageous in terms of work.

Example-4 100 parts by weight of hydroxyl group-containing chlorinated polypropylene obtained in Production Example-1 and Super Beckamine L-127-6
0 and 20 parts by weight of titanium dioxide,
After dispersing the pigment in a sand mill for 1 hour, 20 parts by weight of the acid catalyst of Example-1 was added, and toluene/isopropanol=
Dilute with a mixed solvent of 9515 (weight ratio) to an appropriate viscosity and prepare a polypropylene plate (2X
Spray painted on 5X80ffII11). After drying at room temperature for about 20 minutes, forced drying at 110°C for 30 minutes,
After leaving it standing indoors for 24 hours, the coating film was tested. The results are shown in Table-2.

Example-5 10 parts by weight of the hydroxyl group-containing chlorinated polypropylene 1 modified with maleic anhydride obtained in Production Example-3, 22 parts by weight of Melan 220, and 25 parts by weight of titanium dioxide were mixed to produce Example-4 and 25 parts by weight of titanium dioxide. Pigment dispersion was carried out in the same manner, 10 parts by weight of the acid catalyst of Example-1 was added, a coated plate was prepared in the same manner as in Example-4, and the coating film was tested. The results are shown in Table-2.

Example-6 100 parts by weight of the hydroxyl group-containing chlorinated polypropylene modified with maleic anhydride obtained in Production Example-4 and Melan 1
1 and 25 parts by weight of titanium dioxide,
Pigment dispersion was carried out in the same manner as in Example-4, 10 parts by weight of the acid catalyst of Example-1 was added, a coated plate was prepared in the same manner as in Example-4, and the coating film was tested. The results are shown in Table-2.

Comparative Example-3 100 parts by weight of maleic anhydride chlorinated polypropylene obtained in Production Example-2 and 12 parts by weight of titanium dioxide were mixed, a pigment dispersion and a painted plate were prepared in the same manner as in Example-4, and the coating film was tested. I did it.

Display results Shown in 2.

Table-2 coating film trial experience Conclusion Fruit Test method With arrival Characteristic: Reaches the substrate at 1-intervals on the painted surface Make 100 goban stitches and Put cellophane adhesive tape on top of Place them in close contact and pull in a 180° direction. However, the number of remaining Goban eyes Examined.

Gasoline resistance: A scratch (x) reaching the substrate was made on the coated surface, and the condition of the coated film was examined by immersing it in regular gasoline at 25° C. for 2 hours.

Gender: 1/2φ inch mandrel Bend 1800 and check the condition of the coating film. Examined.

Characteristics: Tested with a DuPont impact tester. Use 1/2φ inch and 500g load. For surface hitting, it is lower than 50an. Lower, if lined, fall from 250 I let it happen.

Soaked in warm water at 50°C for 240 hours, Attack water Tired opposition The condition of the paint film was examined.

Moisture resistance: The coating was left in an atmosphere of 98 parts or more at 50° C. for 240 hours, and the condition of the coating film was examined.

From the coating film test results in Table 2, the acid-curing coating compositions of Examples 4, 5 and 6 show improvements in coating film properties due to crosslinking, such as gasoline resistance, water resistance, moisture resistance, etc. In the case of Example 3, since it is not a curable coating composition, these physical properties are inferior, and a very significant difference appears.

Example 7 100 parts by weight of the hydroxyl group-containing chlorinated polypropylene modified with maleic anhydride obtained in Production Example 4 and Super Beckamine L-105-60 (manufactured by Dainippon Ink & Chemicals Co., Ltd., methyl etherified melamine resin) , non-volatile content 6
0%) and 10 parts by weight of the acid catalyst of Example-1, diluted with the mixed solvent of Example-4 to an appropriate viscosity, and sprayed on a polypropylene plate to a film thickness of 5 to 10μ. Painted. After drying at room temperature for about 20 minutes, apply a low-temperature baking melamine paint (manufactured by Kansai Paint Co., Ltd.) to a film thickness of 30~
The coating was spray coated to a thickness of 40 μm, dried at room temperature for about 20 minutes, forcedly dried at 100° C. for 30 minutes, and allowed to stand indoors for 24 hours before testing the coating film. The resulting coating film has excellent gasoline resistance, bending resistance, impact resistance, moisture resistance, water resistance, etc., and also has extremely good adhesion, making it suitable as a primer for coating polyolefin resins. It can be seen that it can be used as

Procedural amendment (voluntary) February 14, 1989 1゜ Indication of case 1988 Patent application No. 277344 2゜ Title of invention Acid-curable coating composition for polyolefin resin 3゜ Person making amendment Related Patent applicant address: 4-5 Marunouchi-chome, Chiyoda-ku, Tokyo
Name (234) Sanyo Kokusaku Pulp Co., Ltd. 4゜

Claims (8)

[Claims] (1) Hydroxyl group-containing chlorinated polyolefin 95~
An acid-curable coating composition for polyolefin resins comprising 10% by weight of an alkyl etherified amino resin, 5 to 90% by weight of an alkyl etherified amino resin, and an acidic catalyst. (2) The acid-curable coating composition according to claim 1, wherein the hydroxyl group-containing chlorinated polyolefin is modified with an unsaturated polycarboxylic acid or an acid anhydride thereof. (3) A hydroxyl group-containing chlorinated polyolefin is a reaction product obtained by chlorinating a polyolefin and then reacting it with an acrylic monomer, in whole or in part, containing a hydroxyl group in the presence of a radical generator. Claim 1
Acid-curable coating compositions as described. (4) Hydroxyl group-containing chlorinated polyolefin is a polyolefin made of one or more compounds selected from the group consisting of unsaturated polycarboxylic acids or their acid anhydrides, so that the saponification value is 6 to 60. The acid-curing type coating according to claim 1, which is a reaction product obtained by modifying and further chlorinating, and then reacting with an acrylic monomer having a hydroxyl group in whole or in part in the presence of a radical generator. Composition. (5) The acid-curable coating composition according to claim 1, wherein the hydroxyl group-containing chlorinated polyolefin is a combination of the reactant according to claim 3 and the reactant according to claim 4. (6) The acid-curable coating composition according to claim 1, wherein the chlorine content of the hydroxyl group-containing chlorinated polyolefin is 5 to 50% by weight. (7) The acid-curable coating composition according to claim 1, wherein the alkyl etherified amino resin is an alkyl etherified urea resin and/or an alkyl etherified melamine resin or an alkyl etherified benzoguanamine resin. (8) A method for producing an acid-curable coating composition for a polyolefin resin in which the curing reaction does not proceed at temperatures below about 60° C., which comprises mixing a hydroxyl group-containing chlorinated polyolefin, an alkyl etherified amino resin, and an acidic catalyst.