JPS648671B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coating composition, specifically a coating composition used for the protection of polypropylene resins, such as polypropylene, ethylene propylene copolymers, ethylene propylene diene copolymers, etc., or for cosmetic purposes. When applied to polypropylene resin sheets and molded products, the adhesion with polypropylene resin, appearance,
The present invention relates to a coating composition that satisfies gasoline resistance, bending resistance, impact resistance, moisture resistance, water resistance, etc. Polypropylene resin has excellent properties such as chemical resistance, ozone resistance, heat resistance, water resistance, and good electrical properties, and because it is lightweight and inexpensive, it is used in home appliances, automobile parts, and other industrial materials. It is one of the materials whose demand is most expected to grow in the future. However, despite these characteristics, when it comes to automobile parts, for example, various types of plastics are being used to reduce weight from the perspective of energy conservation, and the amount of plastic used is increasing year by year. Its use remains limited. One of the reasons preventing its widespread use is that polypropylene resin is nonpolar and crystalline, making it extremely difficult to paint or adhere. For these reasons, there is a strong desire to develop a coating composition that has good adhesion to polypropylene resins. It has been known that chlorinated polypropylene having a degree of chlorination of 10 wt% to 50 wt% has good adhesion to polypropylene resins or polypropylene films. On the other hand, poly(meth)acrylic acid polymers or copolymers have good weather resistance, good color tone and gloss retention, and have distinctive performance as paints. Many attempts have been made to develop coatings for polypropylene resin sheets and molded products by using both of these together. However, conventional chlorination degree 10wt%~50wt
% chlorinated polypropylene is poly(meth)
The compatibility with acrylic acid polymers or copolymers is insufficient, and when used as a paint, the gloss is reduced. For this reason, attempts have been made to lower the molecular weight of chlorinated polypropylene or poly(meth)acrylic acid polymers or copolymers as a method of improving the compatibility between the two, but this method does not improve the compatibility with other properties, such as resistance. The gasoline properties, moisture resistance, water resistance, etc. deteriorated, and there were problems in practical use. For this purpose, the present inventors have found that the poly(meth)acrylic acid polymer or copolymer has good compatibility with the poly(meth)acrylic acid polymer or copolymer, and even when it is made into a paint, it has good adhesion with the polypropylene resin, appearance, gasoline resistance, The present invention was achieved through intensive efforts to develop a chlorinated polypropylene that satisfies bending resistance, impact resistance, moisture resistance, water resistance, etc. The chlorinated polyolefin used in the present invention, which is obtained by chlorinating a polyolefin modified with one or more compounds selected from the group consisting of unsaturated polycarboxylic acids or their acid anhydrides, is produced by a known method. be able to. Its manufacturing method 1
Examples include polyolefin resins such as crystalline polypropylene, amorphous polypropylene, polybutene-1, polypentene-1, 4-methylpentene-1, low density or high density polyethylene, ethylene-propylene copolymer, etc. alone or in combination. The molten polyolefin resin, which is mixed and thermally melted and, if necessary, reduced in viscosity by thermal decomposition, is modified with an unsaturated polycarboxylic acid or its acid anhydride in the presence of a radical generator in a batch or continuous manner. It can be obtained by dispersing or dissolving in a chlorinated solvent and reacting it by blowing chlorine gas at a temperature of 50 to 120°C under pressure or normal pressure in the presence of a catalyst or under irradiation with ultraviolet rays. Examples of radical generators used in the modification reaction include di-tert-butyl peroxide,
Peroxides such as tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxide benzoate, methyl ethyl ketone peroxide, di-tert-butyl diperphthalate, azobisisobutyronitrile, azobis There are azonitriles such as isopropionitrile. Examples of unsaturated polycarboxylic acids and acid anhydrides used in the modification reaction include maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, fumaric acid, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid anhydride, Examples include aconitic acid. The saponification value of the polyolefin modified with the unsaturated polycarboxylic acid and its acid anhydride used in the present invention is at least 6, preferably 10-60. If the saponification value is too low, good compatibility with other resins and sufficient pigment dispersibility may not be obtained, resulting in separation during paint storage, uneven coloring during painting, etc.
This results in a decrease in gloss. On the other hand, if the saponification value is too high,
Adhesion with polypropylene resin decreases, and when certain organic pigments are dispersed, they tend to gel. The chlorinated polyolefin obtained by chlorinating a polyolefin modified with an unsaturated polycarboxylic acid and its acid anhydride can have a chlorination degree of 10 wt% to 50 wt%, preferably 15 wt% to 50 wt%.
It is 35wt%. If the degree of chlorination is low, the solution condition will be poor, and if the degree of chlorination is high, the adhesion to the polypropylene resin will be poor. The poly(meth)acrylic acid polymers used in the present invention include commonly used polyacrylic acid, polymethyl acrylate, polybutyl acrylate, poly 2-ethylhexyl acrylate, polymethacrylic acid, polymethyl methacrylate. , polyethyl methacrylate, polybutyl methacrylate, poly 2-ethylhexyl methacrylate, acrylic acid-methacrylic acid copolymer, ethyl acrylate butyl methacrylate copolymer, acrylic acid-methacrylic acid 2-ethylhexyl copolymer Polymers or copolymers produced from acrylic acid (methacrylic acid) monomers such as methyl methacrylate glycidyl acrylate copolymers, such as Paraloid (manufactured by Rohm & Haas), Elvacite (manufactured by Dupont), and Thermolac (manufactured by Soken Kagaku). There are commercially available products such as The reason why the above mixing weight ratio of the chlorinated polyolefin and the poly(meth)acrylic acid polymer or copolymer was set to 5/95 to 75/25 is because if it is less than 5/95, the adhesion with the polypropylene resin will decrease. becomes insufficient,
This is because if the ratio is 75/25 or more, the weather resistance of the dried film is insufficient. Next, the present invention will be specifically explained using Examples, but the present invention is not limited thereto. Example 1 500 g of isotactic polypropylene with a melt viscosity of about 2600 cps at 180°C was placed in a three-necked flask equipped with a stirrer, a dropping funnel, and a condenser tube for refluxing the monomer, and the temperature was kept constant at 180°C. Completely melted in the oil bath. After replacing the inside of the flask with nitrogen for about 10 minutes, 20 g of maleic anhydride was added over about 5 minutes while stirring, and then 2 g of di-tert-butyl peroxide was added for 10 minutes.
ml of heptane and poured into the dropping funnel over a period of about 30 minutes. At this time, the temperature inside the system was maintained at 180℃,
After continuing the reaction for about 1 hour, unreacted maleic anhydride was removed over about 30 minutes while reducing the pressure inside the flask using an aspirator. The saponification value of this product was 26. Next, 300 g of this product was put into a glass-lined reaction vessel, 5 carbon tetrachloride was added, and 2
After sufficiently melting at 110° C. under a pressure of Kg/cm ² , gaseous chlorine was blown into the bottom of the reaction vessel while irradiating it with ultraviolet rays until the degree of chlorination reached 24 wt%. After the reaction, the solvent carbon tetrachloride was distilled off using an evaporator and replaced with toluene to obtain a 20 wt % toluene solution of chlorinated polypropylene modified with maleic anhydride. Example 2 500g of isotactic polypropylene used in Example-1, 30g of maleic anhydride and di-
Example using 2 g of tert-butyl peroxide
A maleic anhydride-modified polypropylene having a saponification value of 37 was obtained in the same manner as in Example 1. Next, a chlorination reaction was carried out according to Example-1, and 20 wt% of maleic anhydride-modified chlorinated polypropylene with a degree of chlorination of 24 wt% was
A toluene solution was obtained. Example 3 500 g of isotactic polypropylene used in Example 1, 40 g of maleic anhydride and di-
Using 3 g of tert-butyl peroxide, maleic anhydride and di-tert-butyl peroxide were simultaneously added sequentially over about 30 minutes. Other than that, Example-1
I did it in a similar way. The saponification value of the maleic anhydride-modified polypropylene at this time was 49. Next, a 20 wt% toluene solution of maleic anhydride-modified chlorinated polypropylene with a degree of chlorination of 26 wt% was obtained according to Example-1. Example 4 Using 500 g of an ethylene-propylene copolymer having a melt viscosity of about 5000 cps at 180°C and an ethylene content of 4.2 wt%, 30 g of maleic anhydride, and 3 g of di-tert-butyl peroxide, the reaction temperature was 200 °C. Maleic anhydride and di-tert-butyl peroxide were simultaneously added at a temperature of about 30 minutes. Other than that, the same method as in Example-1 was carried out. The saponification value of the maleic anhydride-modified ethylene-propylene copolymer at this time was 32. Next, a chlorination reaction was carried out according to Example-1, and the degree of chlorination was
24wt% maleic anhydride modified chlorinated ethylene
A 20wt% toluene solution of propylene copolymer was obtained. Example 5 30 parts by weight of the chlorinated polyolefins produced in Examples 1 to 4 were thoroughly mixed with 100 parts by weight of acrylic resin (concentration adjusted to 20 wt% toluene solution), and the mixed solution was poured onto a glass plate. After drying, the condition of the film was observed. The results are shown in Table 1. As a comparative example, the results for commercially available chlorinated polypropylene Super Chron 803MW (manufactured by Sanyo Kokusaku Pulp Co., Ltd.) are also listed.

[Table] Example 6 60 g each of the chlorinated polyolefins (20 wt% toluene solution) produced in Examples 1 to 4, 120 g of acrylic resin Thermolac SA-2 (manufactured by Soken Kagaku Co., Ltd.) and 30 g of titanium oxide were mixed, and the mixture was milled in a sand mill. After kneading the pigment for 1 hour using toluene, the viscosity was adjusted to 16 seconds using a No. 4 food cup, and the resulting paint was spray-painted on a polypropylene plate whose surface had been washed with toluene. Air dry at room temperature for about 30 minutes and then at 60℃
After being force-dried for 30 minutes and left standing at room temperature for one day, the coating film was tested. The results are shown in Table 2. Commercially available chlorinated polypropylene Superchron 803MW as a comparative example
(manufactured by Sanyo Kokusaku Pulp Co., Ltd.) The results of the paint using the same are also described.

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Claims (1)

[Claims] 1 The heat-melting polyolefin is 1 selected from the group consisting of unsaturated polycarboxylic acids or their acid anhydrides.
Chlorinated polyolefin and polyester are modified to have a saponification value of 6 to 60 with a species or two or more compounds, dispersed or dissolved in a chlorinated solvent, and chlorinated to a concentration of 10 wt% to 50 wt% by blowing chlorine gas into the solvent. For paints characterized by having as a main component a resin mixed with an acrylic acid-based and/or polymethacrylic acid-based polymer or a copolymer thereof at a weight ratio in the range of 5/95 to 75/25. Composition.