JPH1036456A - Modified rubber composition, production thereof, and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified ethylene/propylene copolymer rubber composition which has excellent paintability and to which a coating paint firmly adheres, a process for producing the same, and a molding of the same. SOLUTION: The composition is obtained by a process comprising impregnating an ethylene/propylene copolymer rubber with an aromatic unsaturated monomer and an unsaturated monomer having a polar functional group and then polymerizing the monomers under, melt kneading. The molding is obtained form the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified rubber composition having excellent paintability (adhesion) to paints and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, ethylene-propylene- (diene) copolymer rubber as a molding material has been widely used in automobiles, building materials, electric wires, cable insulating parts, household goods, and the like. These ethylene / propylene / (diene) copolymer rubbers are sometimes used without being painted, but the molded articles are often painted for the purpose of cosmetics, protection against scratches, and improvement in weather resistance.

However, ethylene, propylene,
Since the (diene) copolymer rubber is non-polar, there is a problem in that when the coating is performed, the adhesion to the coating film is poor and peeling occurs. Therefore, non-polar ethylene propylene
A method has been proposed in which a polymer such as a functional hydrocarbon polymer is blended with a (diene) copolymer rubber to improve the adhesion to a coating material (Japanese Patent Application Laid-Open No. 60-1192).
However, since the amount of the functional group in the polymer to be blended is small, the adhesion to the coating film is insufficient, so that peeling occurs and the appearance is adversely affected.

Further, a method of improving the adhesion to paint by performing a surface treatment by a primer treatment or a corona treatment has been proposed. For example, a mixture of a halogenated propylene and an amine is mixed with an ethylene / propylene vulcanized rubber. A method has been proposed in which a protective film is formed by applying an undercoat to improve the adhesion to the paint (Japanese Patent Publication No. 51-24369). However, in the primer treatment, the primer is expensive and contains a large amount of an organic solvent, so that a step of collection and removal is required, and the number of steps is increased and it takes time. Further, in the corona treatment, there are problems such as a limitation on the shape of the surface to be treated and an expensive capital investment.

Another method is to improve the adhesion to paint by grafting a polar vinyl monomer to an ethylene / propylene / (diene) copolymer rubber by aqueous suspension polymerization (Japanese Patent Publication No. 58-53643). Gazette). However, the composition is styrene (aromatic vinyl monomer)
And a polar unsaturated monomer such as acrylonitrile are grafted onto an ethylene / propylene / diene copolymer rubber by aqueous suspension polymerization. However, with a functional group such as acrylonitrile, the coatability is insufficient and the reaction time becomes longer due to the fact that it takes time to impregnate styrene, a polar unsaturated monomer, into ethylene-propylene copolymer rubber because of water. Economically disadvantaged. Furthermore, a drying step of the obtained modified rubber composition is necessary and has a drawback that the step becomes complicated, and the method does not sufficiently improve the adhesion of the ethylene / propylene / (diene) copolymer rubber to the paint. Did not.

On the other hand, the applicant has proposed a method of improving the impact resistance of a propylene polymer by using a propylene polymer, an olefin rubber, an aromatic vinyl monomer, and a polar functional group-containing vinyl monomer. Thermoplastic resin composition obtained by a melt-kneading reaction in the presence of a radical initiator
No. 313077). However, this method improves the impact resistance by adding an olefin-based rubber to a propylene-based polymer and performing a melt-kneading graft reaction of an aromatic unsaturated monomer such as styrene and a vinyl monomer having a polar functional group. However, the problem was not that the paintability of the added olefin rubber (particularly, ethylene / propylene / copolymer rubber) was a problem.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a modified ethylene / propylene copolymer rubber composition which is sufficiently adherent to a paint and has excellent coatability and a method for producing the same.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned conventional disadvantages, and as a result, have found that an aromatic unsaturated monomer and an aromatic unsaturated monomer can be added to a melt-kneaded ethylene / propylene copolymer rubber. The amount of graft functional groups is increased by using a polar functional group-containing unsaturated monomer in combination and performing melt-kneading polymerization in a short period of time, compared to a system using a polar functional group-containing unsaturated monomer alone. The inventors have found that the paintability (adhesion) of the molded article with respect to the paint is significantly improved, and have completed the present invention.

That is, according to the present invention, an aromatic unsaturated monomer (B) and a polar functional group-containing unsaturated monomer (C) are added to a molten ethylene / propylene copolymer rubber (A) and melt-kneaded. It consists of a modified rubber composition characterized by being obtained by a polymerization reaction, preferably (A) is JIS
A having a hardness of 35 to 80 and a propylene content of 20 to 60% by weight, preferably a functional group in which the polar functional group-containing unsaturated monomer (C) is selected from a hydroxyl group, a carboxyl group, and an epoxy group Containing unsaturated monomer, preferably 0.5 to 20% by weight based on ethylene-propylene copolymer rubber (A), and preferably aromatic unsaturated monomer (B) A modified rubber composition obtained by adding at least the same amount of the group-containing unsaturated monomer (C) and performing a melt-kneading polymerization reaction, preferably the modified rubber obtained is
The grafting amount of the functional group is 0.5 to 20% by weight, the grafting amount of the aromatic unsaturated monomer is 0.5 to 20% by weight, and the amounts of both are substantially the same. The ethylene-propylene copolymer rubber (A) is preliminarily impregnated with an aromatic unsaturated monomer (B) and a polar functional group-containing unsaturated monomer (C), followed by a melt-kneading polymerization reaction. The present invention provides a method for producing a modified rubber composition, and a molded article using the same.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The ethylene / propylene copolymer rubber (A) used in producing the modified rubber composition of the present invention is a rubbery copolymer containing ethylene and propylene as essential components, and the weight ratio of ethylene: propylene is: Preferably 80:20
~ 40: 60. Mooney viscosity of ethylene propylene copolymer rubber used ML1 + 4 (100
C) is preferably from 10 to 100, more preferably from 20 to 70. A small amount of other monomers other than ethylene and propylene may be copolymerized, for example, butene, pentene, heptene, octene, etc., and diene components such as dicyclopentadiene, ethylidene norbornene, 1,4-pentadiene, 1,4 -Hexadiene,
1,5-cyclooctadiene and the like can be used.

Ethylene / propylene copolymer rubber (A)
Is preferably a copolymer with the above-mentioned monomer having a JIS A hardness of 35 to 80 and a propylene content of preferably 20 to 60% by weight, and specifically, an ethylene / propylene copolymer Rubber, ethylene-propylene-diene (ethylidene norbornene, 1,6-hexadiene, cyclopentadiene) copolymer and the like. In addition, other polymers such as ethylene / butene copolymer, ethylene / acrylic acid copolymer, ethylene / vinyl acetate copolymer, and the like, as long as the properties of the ethylene / propylene / (diene) copolymer rubber are not impaired. Butyl rubber, butadiene rubber and the like can be used in combination. The rubber (A) is usually supplied in the form of pellets, but is more preferably in the form of a powder having a large specific surface area.

The aromatic unsaturated monomer (B) of the present invention includes, for example, styrene, methylstyrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene, dichlorostyrene, bromostyrene and the like. And used alone or as a mixture. Styrene is particularly preferred.

The polar functional group-containing unsaturated monomer (C) of the present invention is preferably a copolymerizable hydroxyl group-containing unsaturated monomer, epoxy group-containing unsaturated monomer, or carboxyl group-containing unsaturated monomer. And the like. For paints (especially urethane paints), by introducing hydroxyl groups into the ethylene / propylene / (diene) copolymer, the reaction at the interface with the paint, adhesiveness, and adhesion are improved. Is preferred because it is possible.

Examples of the hydroxyl group-containing unsaturated monomer include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
Ε-caprolactone is preferably added to monomers such as -hydroxybutyl acrylate and the like and to these monomers.
A lactone-modified hydroxyl (meth) acrylate monomer or the like subjected to an addition reaction of up to 6 mol may be used, and may be used alone or as a mixture. Among them, 2-hydroxyethyl methacrylate is particularly preferred.

Examples of the epoxy group-containing unsaturated monomer include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, methacryl glycidyl ether and the like, and they are used alone or in combination. Among them, glycidyl methacrylate is preferred.

Examples of the carboxyl group-containing unsaturated monomer include maleic anhydride, maleic acid, acrylic acid, methacrylic acid and alkyl esters thereof, and these may be used alone or in combination. Among them, maleic anhydride is preferred.

The amount of the polar functional group-containing unsaturated monomer (C) added during the melt polymerization reaction is preferably 0.5 to 0.5 parts by weight based on 100 parts by weight of the ethylene / propylene copolymer rubber (A).
20 parts by weight, more preferably 1 to 10 parts by weight.
When used at less than 0.5 part by weight, the adhesion to the paint is poor, and film peeling occurs. If the amount exceeds 20 parts by weight, pellets of the ethylene / propylene copolymer rubber cannot be uniformly supplied to the sticky extruder, so that the production of the modified ethylene / propylene copolymer rubber cannot be carried out smoothly.

The amount of the aromatic unsaturated monomer (B) is at least the same as that of the polar functional group-containing unsaturated monomer (C).
Preferably, the amount is required to be 1 to 5 times. In addition, when this melt-kneading polymerization reaction is carried out in less than the same amount or without using the aromatic unsaturated monomer (B) in combination with the polar functional group-containing unsaturated monomer (C), the rubber (A) Since the graft amount of the polar functional group is reduced, adverse effects such as poor adhesion of the modified ethylene / propylene copolymer rubber to the coating material occur, which is not preferable.

The modified rubber thus obtained has a grafting amount of the functional group of 0.5 to 20% by weight and a grafting amount of the aromatic unsaturated monomer of 0.5 to 20% by weight. It is preferred that The term “substantially the same amount” means that the two values are close to each other. %. If the grafting amount of both the functional group and the aromatic unsaturated monomer is less than 0.5% by weight, it is not preferable because the adhesion to the coating material is remarkably reduced.

In the present invention, when the melt-kneading reaction is performed,
It is preferable to use a radical initiator for causing a graft reaction of each unsaturated monomer to the ethylene / propylene copolymer rubber. As a radical initiator, it is easy to dissolve in the unsaturated monomer described above due to the characteristics of the present invention, and a half-life of 1 minute is obtained because the reaction is carried out at the melt-kneading temperature of ethylene-propylene copolymer rubber. Decomposition temperature for 130
It is preferable to use an organic peroxide at 〜250 ° C.

If these specific examples are given, bis- (t-
Butylperoxy-m-isopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,
Dialkyl peroxides such as 5-dimethyl-2,5-di (t-butylperoxy) hexine and 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1- Bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane,
Peroxy ketals such as 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, n-butyl-4,4-bis (t-butylperoxy) valerate And peroxyesters such as 2,5-dimethyl-2,5-di (benzoylperoxy) hexane. The amount of the organic peroxide to be used is preferably 0.1 to 10 parts by weight, more preferably 1 to 100 parts by weight based on 100 parts by weight of the unsaturated monomer.
-5 parts by weight.

As another additive, it is preferable to add a stabilizer to the ethylene / propylene copolymer rubber. However, it is necessary to consider the type and the amount of addition so as not to hinder the polymerization of the aromatic unsaturated monomer (B). For example,
Pentaerythrityl-tetrakis (di-t-butyl-hydroxyphenyl) propionate, octdecyl (di-
hindered phenol-based stabilizers such as t-butyl-hydroxyphenyl) propionate, thiobis (methyl-t-butylphenol), and trimethyl-tris (di-t-butylhydroxybenzyl) benzene; tetrakis (di-t-butylphenyl) biphenylene Phosphite,
There are phosphorus-based stabilizers such as tris (di-t-butylphenyl) phosphite, metal soaps such as zinc stearate and calcium stearate, and antacid adsorbents such as magnesium oxide and hydrotalcite. The amount of the stabilizer used is preferably 0.01 to 1 part by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the ethylene / propylene copolymer rubber.
0.5 parts by weight. Further, additional components can be added within a range that does not impair the effects of the invention.

Additional components include, for example, inorganic fillers,
Pigments, flame retardants, reinforcing materials and the like. Specifically, calcium carbonate, calcium silicate, clay, talc, silica sand, glass powder, silica, carbon black, aluminum hydroxide, alumina and the like are used as the inorganic filler, and glass fiber, carbon fiber, and metal fiber are used as the reinforcing material. And the like.

The melt-kneading polymerization reaction of the ethylene / propylene copolymer rubber (A) with the aromatic unsaturated monomer (B) and the polar functional group-containing unsaturated monomer (C) is carried out by a dense line such as a Banbury mixer. It is possible by using a continuous kneader such as a closed container or an extruder. An extruder is preferable when industrial production such as granulation is considered. Further, the twin-screw extruder is easier to control the supply, kneading, and polymerization time of the reactants.

In the method for producing the modified ethylene / propylene copolymer rubber, the ethylene / propylene copolymer rubber in the form of crumb or pellets is supplied to an extruder,
Melt kneading polymerization of aromatic unsaturated monomer (B) and polar functional group-containing unsaturated monomer (C) while heating ethylene-propylene copolymer rubber (A) at 250 ° C in a cylinder to melt it After the reaction, cool the strand discharged from the die,
Pelletize using a pelletizer.

The aromatic unsaturated monomer (B) and the polar functional group-containing unsaturated monomer (C) may be mixed with an ethylene / propylene copolymer rubber in advance and then supplied to an extruder, The ethylene-propylene copolymer rubber (A) in a molten state may be supplied using a liquid feeder, but it is preferable that the ethylene-propylene copolymer rubber is previously mixed and impregnated with the ethylene-propylene copolymer rubber.

The radical initiator may be added by dissolving it in the unsaturated monomers (B) and (C) in advance, or the ethylene-propylene copolymer rubber and the unsaturated monomer may be added using a liquid feeder. It may be added to a mixture with the body. It is preferable that the stabilizer is previously mixed with the ethylene / propylene copolymer rubber using a Henschel mixer or the like.

The modified rubber composition thus obtained is used as a molding material, and a molded article having excellent coatability (adhesion) to paint can be obtained by injection molding, extrusion molding, and press molding. The molded article is a mold, a film, a sheet, a tube, or the like obtained by injection molding or extrusion molding, and can be laminated on metal or another resin, and can also be used as a laminate.

Thus, the present invention can provide a modified rubber composition having excellent paintability (adhesion) to paint.

[0030]

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and percentages are by weight unless otherwise specified. The molding and physical property evaluation of the modified rubber composition are as follows.

"Hardness" According to JIS K7311, J
The hardness of the dumbbell-shaped specimen was measured using an IS hardness tester.

"MFR" The measurement was carried out using a melt indexer manufactured by Toyo Seiki under the conditions of 230 ° C and a load of 2.16 kg.

"Tensile properties" For each sample, a dumbbell-shaped specimen was obtained from a plate having a thickness of 2 mm formed by press molding, and the tensile strength and elongation were measured according to JIS K73111.

"Paintability" Acrylic-urethane two-liquid paint (Rethane PG60 / Hardner, manufactured by Kansai Paint Co., Ltd.) was applied to a press-formed plate having a thickness of 2 mm to a thickness of about 40 μm using an applicator. The composition was cured and dried at 30 ° C. for 30 minutes. Next, a 1 mm square grid (10 × 10 pieces) was formed on the coating film, a cellophane tape peeling test was performed, and the coating property was evaluated based on the number of remaining coating films.

The remaining number of coating films was evaluated as <○> when 95 or more, <以上> when less than 80, and <X> when less than 80.

"Functional Graft Amount"
Infrared spectroscopy (IR) of a resin obtained by blending a homopolymer of each monomer with propylene / (diene) copolymer rubber
According to the analysis, the absorbance ratio (carbonyl group · 1720 cm ⁻¹ /
Methyl · 1380 cm ^-1 and C = C · 700cm ^-1
/ Methyl group · 1380 cm ⁻¹ ) and the homopolymer content were plotted to prepare a calibration curve in advance, and I
R was measured, and the functional group graft amount was calculated from the absorbance ratio.

(Example 1) A 30 mmφ twin screw extruder manufactured by Brabender Co. (Germany) was set to a barrel temperature of 200 ° C (however, a feeder section of 160 ° C) and a die of 210 ° C. Pellets of ethylene-propylene copolymer rubber (EP0
2P, propylene content 26 wt%, MFR 3.2 g / 1
0 min, hardness JIS 55A, manufactured by Japan Synthetic Rubber) 90
In 0 parts, 0.5 parts of Irganox 1010 (stabilizer manufactured by Ciba-Geigy), 0.5 parts of phosphite 168 (stabilizer manufactured by Ciba-Geigy), and calcium stearate (stabilizer)
1.0 part was mixed with a Henschel mixer. A mixture of 50 parts of styrene and 50 parts of 2-hydroxyethyl methacrylate and 1.0 part of Perhexin 25B (manufactured by NOF CORPORATION) was mixed and stirred with the above-mentioned pelletized ethylene / propylene copolymer rubber. Fine seal X-37 (fine powdered silica manufactured by Tokuyama Corporation) 30 is added to the obtained mixed and stirred mixture.
Additional parts were added and mixed. The obtained mixture was supplied to an extruder, melt-kneaded in the extruder at 20 rpm to perform a graft reaction, and a modified ethylene-propylene copolymer rubber (hereinafter abbreviated as modified EPM-1) was obtained through a pelletizer.

The graft contents of 2-hydroxymethacrylate and styrene in the extruded product were 4.5% by weight and 4.8% by weight, respectively, from the calibration curve. Moreover, the peeling state of the coating film in the coating property evaluation was good.

(Example 2) In the production of the modified ethylene / propylene-based polymer rubber of Example 1, 900 parts of pelletized ethylene / propylene-based copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), 50 parts of styrene, In the same manner as in Example 1, a modified ethylene-propylene system was added in the same manner as in Example 1 except that 50 parts of glycidyl methacrylate was used instead of 2-hydroxymethacrylate as the functional group-containing unsaturated monomer, and 1.0 part of perhexin 25B (manufactured by NOF CORPORATION) was added. A copolymer rubber (hereinafter, abbreviated as modified EPM-2) was produced.

The graft content of the functional group and styrene in the obtained product was 4.4% by weight and 4.2% by weight, respectively. In addition, the peeling state of the coating film in the evaluation of the coating property was as good as in Example 1.

Example 3 In the production of the modified ethylene / propylene polymer rubber of Example 1, 980 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), styrene 10 parts, polarity As a functional group-containing unsaturated monomer, 2-hydroxyethyl methacrylate was replaced with 10 parts of maleic anhydride, and perhexin 25 was used.
B (manufactured by NOF CORPORATION), and modified ethylene / propylene-based copolymer rubber (hereinafter referred to as “Example 1”) in the same manner as in Example 1.
Modified EPM-3) was produced.

The graft content of the functional group and styrene in the obtained product was 0.8% by weight and 0.7% by weight, respectively. In addition, the peeling state of the coating film in the evaluation of the coating property was as good as in Example 1.

Example 4 In the production of the modified ethylene / propylene polymer rubber of Example 1, 984 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), 10 parts of styrene, Modified ethylene / propylene copolymer rubber (hereinafter abbreviated as modified EPM-4) in the same manner as in Example 1 except that 0.16 parts of perhexin 25B (manufactured by NOF Corporation) was added instead of 6 parts of hydroxymethacrylate. Was manufactured.

The functional group and styrene graft content of the obtained product were 0.9% by weight and 0.55% by weight, respectively. In addition, the peeling state of the coating film in the evaluation of the coating property was as good as in Example 1.

Example 5 In the production of the modified ethylene / propylene polymer rubber of Example 1, 984 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), 10 parts of styrene, polarity As a functional group-containing unsaturated monomer, 6 parts of glycidyl methacrylate was used instead of 2-hydroxymethacrylate, and 0.16 part of perhexin 25B (manufactured by NOF Corporation) was added. Propylene-based copolymer rubber (hereinafter abbreviated as modified EPM-5) was produced.

The graft content of the functional group and styrene of the obtained product was 0.9% by weight and 0.55% by weight, respectively. In addition, the peeling state of the coating film in the evaluation of the coating property was as good as in Example 1.

Example 6 In the production of the modified ethylene / propylene polymer rubber of Example 1, 984 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), 10 parts of styrene, polarity As the functional group-containing unsaturated monomer, 6 parts of maleic anhydride was used in place of 2-hydroxymethacrylate, and perhexin 25B was used.
0.16 parts (manufactured by NOF CORPORATION) were added, and modified ethylene / propylene copolymer rubber (hereinafter, referred to as “Example 1”)
Modified EPM-6).

The graft content of the functional group and styrene in the obtained product was 0.9% by weight and 0.52% by weight, respectively. In addition, the peeling state of the coating film in the evaluation of the coating property was as good as in Example 1.

(Comparative Example 1) In the production of the modified ethylene / propylene polymer rubber of Example 1, 950 parts of an ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber Co., Ltd.) in the form of pellets, and no polar functional group-containing rubber Using 50 parts of 2-hydroxyethyl methacrylate alone as a saturated monomer, perhexin 25B (manufactured by NOF CORPORATION).
Modified ethylene / propylene copolymer rubber (hereinafter abbreviated as modified EPM-7) in the same manner as in Example 1 with the addition of 5 parts.
Was manufactured.

The resulting product had a functional group graft content of 1.0% by weight. In the coating property evaluation, the peeling state of the coating film was extremely poor, and the adhesion was reduced. It is considered that the reason for this is that, unless an aromatic unsaturated monomer such as styrene is used in combination, the grafting amount of the functional group is reduced as compared with Example 1 and the adhesion to the coating material is reduced. Also,
Compared with Example 4, although the amount of the functional group graft was large, it was considered that the paintability was poor because it was not a styrene combination system.

Comparative Example 2 In the production of the modified ethylene / propylene copolymer rubber of Example 1, 950 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber Co., Ltd.), polar functional group-containing unsaturated Using 50 parts of glycidyl methacrylate alone as a monomer, adding 0.5 parts of perhexin 25B (manufactured by NOF CORPORATION), and modifying the modified ethylene / propylene copolymer rubber (hereinafter, modified) in the same manner as in Example 1. EPM-8).

The obtained product had a functional group graft content of 1.5% by weight. In the coating property evaluation, the peeling state of the coating film was extremely poor, and the adhesion was reduced. The same reason as in Comparative Example 1 can be considered for this result.

Comparative Example 3 In the production of the modified ethylene / propylene copolymer rubber of Example 1, 990 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber Co., Ltd.), polar functional group-containing unsaturated Using 10 parts of maleic anhydride alone as a monomer, perhexin 2
5B (manufactured by NOF CORPORATION) was added, and a modified ethylene / propylene copolymer rubber (hereinafter abbreviated as modified EPM-9) was produced in the same manner as in Example 1.

The obtained product had a functional group graft content of 0.1% by weight. The paintability evaluation is also bad,
The cause is considered to be the same as in Comparative Examples 1 and 2.

Comparative Example 4 In the production of the modified ethylene / propylene copolymer rubber of Example 1, 950 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber), 50 parts of styrene alone as a monomer, 0.5 part of perhexin 25B (manufactured by NOF CORPORATION) was added, and a modified ethylene / propylene copolymer rubber (hereinafter referred to as modified EP) was prepared in the same manner as in Example 1.
M-10).

The styrene graft content of the obtained product was 3.0% by weight. The paintability was not good in the evaluation, and it was found that the paintability was not effective unless a functional group was introduced by the grafting reaction.

(Comparative Example 5) In the production of the modified ethylene / propylene copolymer rubber of Example 1, 950 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber) were used instead of the unsaturated monomer. Then, 50 parts of polystyrene (CR-4500, manufactured by Dainippon Ink and Chemicals, Inc.) was added to the mixture, and a modified ethylene / propylene copolymer rubber (hereinafter abbreviated as modified EPM-11) was prepared in the same manner as in Example 1.
Was manufactured.

In the evaluation of coating properties, the peeling state of the coating film was not so good. Further, the obtained molded product was white, the transparency was inferior to those of the examples, and the compatibility was poor.

Comparative Example 6 In the production of the modified ethylene / propylene copolymer rubber of Example 1, 1000 parts of pelletized ethylene / propylene copolymer rubber (EP02P, manufactured by Nippon Synthetic Rubber) were used. A modified ethylene / propylene copolymer rubber (hereinafter abbreviated as modified EPM-12) was produced in the same manner as described above.

In the evaluation of paintability, the coating film was peeled off without adhering to the molded product at all.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3] ^* It is styrene content, not styrene graft amount.

[0064]

According to the present invention, an aromatic unsaturated monomer and a hydroxyl group are added to a molten ethylene / propylene / copolymer rubber.
By melt-kneading polymerization of a polar functional group-containing unsaturated monomer selected from an epoxy group and a carboxyl group,
A modified rubber composition modified with a functional group, and extruded products such as tubes, hoses, films, sheets, etc., which are excellent in paintability (adhesion) to paints, as well as laminate molded products and injection molded products to metals and other resins. The purpose of the present invention is to provide a molding material which can be applied to the material.

Claims (8)

[Claims] 1. An ethylene / propylene copolymer rubber (A)
A modified rubber composition obtained by adding an aromatic unsaturated monomer (B) and a polar functional group-containing unsaturated monomer (C) to a mixture and subjecting the mixture to a melt-kneading polymerization reaction. 2. An ethylene / propylene copolymer rubber (A)
The modified rubber composition according to claim 1, wherein the rubber composition has a JIS A hardness of 35 to 80 and a propylene content of 20 to 60% by weight. 3. The polar functional group-containing unsaturated monomer (C),
3. It contains a polar functional group selected from a hydroxyl group, a carboxyl group, and an epoxy group.
The modified rubber composition according to any one of the above. 4. The addition amount of the polar functional group-containing unsaturated monomer (C) is 100 or less of the ethylene / propylene copolymer rubber (A).
The modified rubber composition according to any one of claims 1 to 3, wherein the amount is 0.5 to 20 parts by weight based on part by weight. 5. The modified product according to claim 1, wherein the aromatic unsaturated monomer (B) is added in the same amount or more as the polar functional group-containing unsaturated monomer (C). Rubber composition. 6. The modified rubber thus obtained has a grafting amount of a functional group of 0.5 to 20% by weight and a grafting amount of an aromatic unsaturated monomer of 0.5 to 20% by weight, and the amounts of both are almost the same. The modified rubber composition according to any one of claims 1 to 5, wherein 7. An ethylene / propylene copolymer rubber (A)
A method for producing a modified rubber composition, comprising adding and impregnating an aromatic unsaturated monomer (B) and a polar functional group-containing unsaturated monomer (C) in advance, followed by melt-kneading polymerization reaction. 8. A molded article obtained from the modified rubber composition according to any one of claims 1 to 7.