JPH0657063A - Wheel cover for automobile - Google Patents

Abstract

PURPOSE:To provide the wheel cover, having good balance of rigidity, impact strength, heat resistance, etc., and high practical use value, which is produced by injection molding a thermoplastic resin composition obtained by blending specific amounts of a specific vinyl-based copolymer, a polyamide and a modified polyolefin. CONSTITUTION:(A) 5-90wt.% vinyl-based copolymer obtained by polymerizing (i) 5-95wt.% one or more vinyl-based copolymers selected from an aromatic vinyl-based monomer and (meth)acrylic ester-based monomer with (ii) 5-95wt.% maleimide-based monomer of the formula (R1 to R3 are each H, halogen, etc.) and (iii) 0.05-50wt.% other vinyl-based copolymer copolymerizable with the component (i) and the component (ii) is blended with (B) 3-90wt.% polyamide, (C) 5-60wt.% modified polyolefin containing one or more functional groups of a carboxylic acid group, a carboxylic acid metal base and an acid anhydride group and optionally pigment, filler, thermal stabilizer, etc., to give a thermoplastic composition, which is injection molded to give the objective cover.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A wheel cover which is one of automobile parts is strongly desired to have a balance of heat resistance, impact resistance, high rigidity, weather resistance, light weight and good appearance.

The present invention relates to an automobile wheel cover having the above-mentioned performance in good balance.

[0003]

BACKGROUND ART Modified polyphenylene ether, glass- or filler-reinforced polyamide, alloy of polyamide and polyphenylene ether, etc. are typical of those currently used for automobile wheel covers.

However, although the modified polyphenylene ether has good impact resistance and light weight, it has problems in weather resistance and heat resistance. Although glass or filler-reinforced polyamide has good heat resistance, high rigidity and weather resistance, it has problems in impact resistance and light weight. Polyamide, polyphenylene ether,
A combination of a styrene-butadiene-styrene block copolymer (for example, Japanese Patent Application No. 61-146433) has a well-balanced performance as a wheel cover, but has a problem of poor weather resistance and remarkable weather discoloration. Further, a combination of polyamide and imidized ABS (for example, Japanese Patent Laid-Open No. 63-179957) has good impact resistance and weather resistance, but has problems in heat resistance and rigidity. On the other hand, as a resin composition having excellent impact resistance, a mixture of polyamide and modified polyolefin (for example, Japanese Patent Publication No.
44108), styrene-maleimide copolymer,
A mixture of polyamide and modified polyolefin (Japanese Patent Laid-Open No. 62-59647) is known.

[0005]

However, a wheel cover that has a truly required performance in a well-balanced manner has not yet been obtained, and it is currently desired to develop a wheel cover that has these well-balanced performances in a well-balanced manner. Is.

The present inventors have conducted intensive studies for the purpose of developing a wheel cover in which heat resistance, impact resistance, high rigidity, weather resistance, light weight, and good appearance are balanced, and as a result, a specific vinyl-based copolymer, The inventors have found that the above object can be achieved by injection molding a thermoplastic resin composition obtained by blending a polyamide and a specific modified polyolefin in a specific ratio, and have reached the present invention.

[0007]

That is, the present invention provides (A) at least one vinyl selected from the group consisting of (a) aromatic vinyl-based monomers and (meth) acrylic acid ester-based monomers. 5 to 95% by weight of monomer, (b) general formula (1)

[0008]

[Chemical 2]

5 to 95% by weight of a maleimide monomer represented by the formula (wherein R 1, R 2 and R 3 each represent hydrogen, halogen, a substituted or unsubstituted hydrocarbon having 1 to 20 carbon atoms), and (C) 0.05 to 5 other vinyl-based monomer copolymerizable with (a) and / or (b) above
Vinyl-based polymer obtained by polymerizing 0% by weight (B) Polyamide and (C) Modified polyolefin having at least one functional group selected from the group consisting of carboxylic acid group, metal carboxylate group and acid anhydride group. (A) is 5 to 90% by weight,
3 to 90% by weight of (B) and 5 to 60% by weight of (C)
The present invention provides a wheel cover for an automobile, which is obtained by injection-molding a thermoplastic resin composition obtained by mixing at a ratio of.

In the vinyl copolymer (A) used in the present invention, the vinyl monomer (a) means styrene, α-methylstyrene, P-methylstyrene, Pt-butylstyrene, vinyltoluene and P. -Aromatic vinyl monomers such as chlorostyrene, and methyl methacrylate, ethyl methacrylate, -t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, etc. It is at least one vinyl-based monomer selected from the group consisting of (meth) acrylic acid ester-based monomers.

Among the above vinyl-based monomers (a), styrene, α-methylstyrene, P-methylstyrene and methyl methacrylate are preferable, and styrene is particularly preferable.

The maleimide-based monomer (b) is not particularly limited as long as it satisfies the general formula (1), but specific examples include maleimide, N-methylmaleimide and N-.
Ethyl maleimide, N-isopropyl maleimide, N-
t-butyl maleimide, N-phenyl maleimide, N-
m-methylphenylmaleimide, N-o-methylphenylmaleimide, Np-methylphenylmaleimide, N
-Cyclohexylmaleimide, N-o-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide, N-o-
Methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, Np-methoxyphenylmaleimide,
N-o-chlorophenylmaleimide, Nm-chlorophenylmaleimide Np-chlorophenylmaleimide,
Examples thereof include N-o-carboxyphenylmaleimide, Np-carboxyphenylmaleimide, Nm-carboxyphenylmaleimide, dichloromaleimide and N-naphthylmaleimide.

Of these, N-phenylmaleimide, N-cyclohexylmaleimide, Nt-butylmaleimide, N-isopropylmaleimide and Nm-
Methylphenylmaleimide is preferred.

These may be used alone or in combination of two or more.

The vinyl-based monomer (c) is copolymerizable with (a) and / or (b), and is not particularly limited as long as it is a vinyl-based monomer other than (a) and / or (b). Examples thereof include vinyl cyanide-based monomers such as acrylonitrile and methacrylonitrile, acrylic acid, methacrylic acid, and maleic anhydride. Of these, maleic anhydride is particularly preferable.

In the polymerization of the vinyl-based copolymer (A), the proportion of the monomers (a), (b) and (c) is such that (a) is 5 to 95% by weight, preferably 10 to 90. %, Particularly preferably 15 to 80% by weight, (b) is 5 to 95% by weight,
Preferably 15 to 90% by weight, particularly preferably 15 to 85
% And (c) is 0.05 to 50% by weight, preferably 0.1 to 40% by weight, particularly preferably 0.2 to 35.
% By weight.

When (a) is less than 5% by weight or more than 95% by weight, (B) is less than 5% by weight or more than 95% by weight, or (C) is less than 0.05% by weight or 50% by weight. If it exceeds the range, the vinyl-based copolymer (A) is inferior in mechanical properties, thermal stability and melt fluidity, and a resin composition having desired performance cannot be obtained, which is not preferable.
In particular, (a) exceeds 95% by weight, or (b) is 5
If it is less than wt%, the Tg of the vinyl copolymer (A) is low and the heat resistance is insufficient, which is not preferable. When (c) is less than 0.05% by weight, the heat resistance of the resin composition obtained due to insufficient affinity between the vinyl copolymer (A) and the polyamide (B) and / or modified polyolefin (C) And mechanical properties are inferior, which is not preferable, and when it exceeds 50% by weight, the fluidity of the resin composition obtained by kneading the vinyl copolymer (A), the polyamide (B) and the modified polyolefin (C) is lowered, and molding is performed. Is impaired, which is not preferable.

In the polymerization of vinyl copolymer (A), polybutadiene (PBD), acrylonitrile-
Butadiene copolymer rubber (NBR), styrene-butadiene copolymer rubber (SBR), polybutyl acrylate rubber, ethylene-propylene copolymer rubber (EPR), ethylene-propylene, non-conjugated diene copolymer rubber (EP
DM) in the presence of various rubber-like polymers (a),
It is also possible to polymerize (b) and (c) in a predetermined ratio.

There is no particular limitation on the polymerization method of the vinyl copolymer (A), and bulk polymerization, solution polymerization, bulk-suspension polymerization, suspension polymerization in the presence or absence of a radical-generating initiator. , Emulsion polymerization, etc. are used. There is no particular limitation on the charging method of the vinyl monomers (a), (b) and (c), and they may be charged all at once at the beginning, or a part or all of the charged monomers may be continuously charged or divided. Polymerization may be carried out while charging.

Further, α and β represented by maleic anhydride
-Production by reacting a copolymer obtained by copolymerizing an unsaturated dicarboxylic acid or its anhydride with ammonia or amines such as methylamine, ethylamine, t-butylamine, cyclohexylamine and aniline, and then imidizing the same. Is also possible.

The vinyl-based copolymers obtained by the monomer polymerization method and the post-imidization method are included in the vinyl-based copolymer (A) of the present invention if the final compositions are the same. The method of manufacturing by the chemical method is more preferable.

The polyamide (B) used in the present invention means ε
-Polyamide obtained by ring-opening polymerization of lactams such as caprolactam and ω-dodecalactam, polyamide derived from amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, ethylenediamine, tetramethylenediaminehexa Methylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 1,3- and 1,4-bis (aminomethyl) cyclohexane, bis (4, 4'-aminocyclohexyl) methane, aliphatic, alicyclic and aromatic diamines such as meta and paraxylylenediamine and adipic acid, suberic acid, sebacic acid, dodecanedioic acid,
1,3- and 1,4-cyclohexanedicarboxylic acid,
Polyamides derived from aliphatic, alicyclic and aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid and dimer acid, and copolyamides and mixed polyamides thereof. Of these, polycaproamide (nylon 6), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polyhexamethylene dipamide (nylon 66), and copolyamides containing these as the main components are usually used. Are more useful, and nylon 6, nylon 66, copolymers thereof, and nylon obtained by copolymerizing terephthalic acid are also useful. As a method for polymerizing the polyamide, generally known melt polymerization, solid phase polymerization and a combination of these methods can be adopted. The degree of polymerization of polyamide is not particularly limited, and the relative viscosity (measured at 25 ° C. by dissolving 1 g of polymer in 100 ml of 98% concentrated sulfuric acid) is 2.0 to
A polyamide in the range of 5.0 can be arbitrarily selected according to the purpose, and two or more polyamides of the same kind having different relative viscosities may be used.

Modified polyolefin (C) used in the present invention
There is no particular limitation as long as it is a polyolefin having at least one functional group selected from the group consisting of a carboxylic acid group, a carboxylic acid metal base and an acid anhydride group. Typical examples are ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, ethylene / fumaric acid copolymers, ethylene / methacrylic acid / zinc methacrylate copolymers, ethylene / acrylic acid / sodium methacrylate copolymers. Polymer, ethylene / isobutyl acrylate / methacrylic acid / zinc methacrylate copolymer, ethylene / methyl methacrylate / methacrylic acid / magnesium methacrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / ethyl acrylate / Acrylic acid copolymers, ethylene / maleic anhydride copolymers, ethylene / propylene / maleic anhydride copolymers, ethylene-g-maleic anhydride copolymers (“g” represents a graft. The same applies hereinafter),
Ethylene / propylene-g-maleic anhydride copolymer,
Ethylene / propylene-g-acrylic acid copolymer, ethylene / 1-butene-g-fumaric acid copolymer, ethylene /
1-hexene-g-itaconic acid copolymer, ethylene / propylene-g-endocyclo [2,2,1] -5-heptene-2,3-dicarboxylic anhydride copolymer, ethylene / propylene / 1,4- Examples include hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride copolymer, ethylene / vinyl acetate-g-acrylic acid copolymer, and the like.
It is not limited to these. It is also possible to use two or more of these modified polyolefins in combination.

The modified polyolefin (C) is usually used in a known method, for example, JP-B-39-6810 and JP-B-52.
-43677, Japanese Patent Publication No. 53-5716, Japanese Patent Publication No. 53-19037, Japanese Patent Publication No. 53-41173.
It can be produced by the method disclosed in Japanese Patent Publication No. 56-9925 and Japanese Patent Publication No. 56-9925. As the ethylene-based ionomer, various grades generally marketed under the trade names of "HIMILAN" and "COPOLEN" can be used.

In the thermoplastic resin composition of the present invention, the blending ratio of the vinyl copolymer (A), the polyamide (B) and the modified polyolefin (C) is (A) 5 to 90% by weight,
Preferably 15 to 80% by weight, particularly preferably 20 to 7
0% by weight, (B) is 3 to 90% by weight, preferably 5 to 8
0% by weight, particularly preferably 10 to 70% by weight, and (C) 5 to 60% by weight, preferably 15 to 40% by weight
Is the ratio. If the content of (A) is less than 5% by weight, the rigidity and heat distortion temperature will be poor, and if the content of (A) exceeds 90% by weight, the impact resistance will be poor, which is not preferable. When (B) is less than 3% by weight or (C) is less than 5% by weight, impact resistance is poor,
If the content of (B) exceeds 90% by weight or the content of (C) exceeds 60% by weight, the rigidity becomes poor, which is not preferable.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and a generally known method can be adopted. That is, the vinyl-based copolymer (A), the polyamide (B) and the modified polyolefin (C) are uniformly mixed in a pellet, powder or strip state using a high-speed stirrer or the like, and then uniaxial with sufficient kneading ability. Or a method of melt-kneading with a multi-screw extruder and a Banbury mixer,
Various methods such as a method of melt kneading using a rubber roll machine can be adopted. Further, the vinyl copolymer (A) and the polyamide (B), the polyamide (B) and the modified polyolefin (C), the vinyl copolymer (A) and the modified polyolefin (C), and the like are pre-kneaded in advance, A method of adjusting the mixture ratio to a predetermined value and kneading afterwards is also possible.

The thermoplastic resin composition of the present invention comprises, in addition to the vinyl copolymer (A), the polyamide (B) and the modified polyolefin (C), a pigment, a dye, a filler,
A heat stabilizer, an antioxidant, a lubricant, a plasticizer, an antistatic agent, etc. can be added.

Further, the weather resistance can be further improved by adding an ultraviolet absorber and a light stabilizer.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

Various physical properties described in Examples and Comparative Examples were measured by the following methods.

1. Bending characteristics: ASTM D790 2. Izod impact strength: ASTM D256 3. Heat distortion temperature: ASTM D648 4. Weather resistance: The wheel cover molded by Toshiba IS-630CN injection molding machine was treated with a Suga Test Instruments fade meter at a black panel temperature of 83 ° C. for 500 hours, and ΔE * (color difference) measured by a Suga Test Instruments color machine was measured. When it was 3 or less, it was evaluated as O, and when ΔE * was 3 or more, it was evaluated as x.

5. Appearance: A wheel cover was molded with a Toshiba IS630CN injection molding machine, and the appearance was visually judged.

6. Formability: Toshiba IS-630CN
A wheel cover was molded under the same conditions with an injection molding machine, and it was visually judged whether the molded product was completely filled or whether there was any deformation.

Reference Example 1 A-1: A polymerization tank was charged with 65 parts of styrene and 0.5 part of azoisobutyronitrile, and the temperature was adjusted to 80 ° C., while stirring, 30 parts of N-phenylmaleimide and maleic anhydride. 5
Part and 80 parts of methyl ethyl ketone was charged at a constant rate over 8 hours. Then raise the temperature to 90 ° C and
Held for hours. A transparent and viscous solution was obtained, and the solvent was removed to obtain a vinyl-based copolymer (A-1).

A-2: 20 parts of styrene, 70 parts of N-cyclohexylmaleimide, 10 parts of maleic anhydride, 0.5 part of benzoyl peroxide and 1 part of methyl ethyl ketone in a polymerization tank.
00 parts were charged, and the mixture was polymerized at 80 ° C. for 8 hours and further heated to 90 ° C. for 2 hours. A transparent and viscous solution is obtained, and by removing this solvent, the vinyl copolymer (A-2)
Got

A-3: 200 parts of water and 0.3% of polyvinyl alcohol (suspension stabilizer) having a saponification degree of 80% in a polymerization tank.
Then, 40 parts of styrene, 40 parts of N-phenylmaleimide, 15 parts of acrylonitrile, 5 parts of maleic anhydride and 0.5 part of azoisobutyronitrile were charged.
The suspension was stirred at high speed to obtain a suspension. While maintaining the suspension state, polymerization was carried out at 80 ° C. for 6 hours and further at 90 ° C. for 1 hour to obtain a granular vinyl copolymer (A-3).

Reference Example 2 B-1: Nylon 6 having a relative viscosity of 2.7 concentrated sulfuric acid was melt-polymerized from ε-caprolactam.

B-2: Nylon 66 having a relative viscosity of concentrated sulfuric acid of 2.9 was obtained by melt polymerization from a molar salt of hexamethylenediamine and adipic acid.

B-3: Copolymerized nylon 66 having a relative viscosity of 2.5 with concentrated sulfuric acid by melt polymerization from a mixed salt of 65 wt% of hexamethylenediamine / adipic acid molar salt and 35 wt% of hexamethylenediamine / terephthalic acid molar salt. / Nylon 6T = 65/35 wt% was obtained.

Reference Example 3 C-1: 85% by weight of ethylene and 15% by weight of methacrylic acid
Is copolymerized in the presence of a peroxide according to the production conditions of high-pressure polyethylene, and an amount of zinc acetate capable of neutralizing and ionizing 75% of the obtained copolymer-containing methacrylic acid is added, followed by 180 using a roll mill. The mixture was kneaded uniformly at 0 ° C to obtain an ethylene / methacrylic acid / zinc methacrylate copolymer (ionomer resin) C-1.

C-2: α, dissolved in a small amount of acetone, based on 100 parts by weight of an ethylene / propylene copolymer consisting of 70 mol% of ethylene and 30 mol% of propylene.
α'-Bis-t-butylperoxy-p-diisopropylbenzene 0.03 part by weight and maleic anhydride 1.0
After adding parts by weight, 230 mm using a 40 mmφ extruder
Ethylene / propylene-g-maleic anhydride copolymer (“g” represents graft) C-2 was obtained by kneading at ℃ and pelletizing.

C-3: an ethylene / propylene-5-ethylidene-2-norbornene (EPDM) terpolymer having a Mooney viscosity of 60 and an iodine value of 12 (ethylene / propylene = 68.5 / 31.5 (molar ratio)) ) To 100 parts by weight, 0.1 part by weight of di-t-butyl peroxide dissolved in a small amount of acetone and 0.5 part by weight of maleic anhydride were added, and then a 40 mmφ extruder was used as in C-2. EPDM by kneading and pelletizing at 230 ℃
A -g-maleic anhydride copolymer C-3 was obtained.

Example 1 40% by weight of the vinyl copolymer (A-1) obtained in Reference Example 1, 40% by weight of the polyamide (B-1) obtained in Reference Example 2, obtained in Reference Example 3 Modified polyolefin (C-
1) 20 wt% was dry-blended using a Henschel mixer, then fed to the hopper of a 30 mmφ twin-screw kneader, cylinder temperature 280 ° C., screw rotation speed 200
The mixture was melt-kneaded under the conditions of rpm and pelletized. After vacuum-drying the pellets at 100 ° C. for 24 hours, injection molding was performed under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C. to mold a wheel cover, and at the same time, various test pieces for evaluating physical properties were obtained. The properties of the test pieces are shown in Table 1, and the automobile wheel cover using the resin composition obtained here was excellent in rigidity, impact resistance, heat resistance, weather resistance and appearance.

Comparative Example 1 70% by weight of the vinyl-based copolymer (A-1) obtained in Reference Example 1 without using the polyamide (B) and the modified polyolefin (C-1) 30 obtained in Reference Example 3 Melt kneading, injection molding, and property evaluation were carried out in the same manner as in Example 1 except that the weight% was used, and the results shown in Table 1 were obtained. The molded product obtained here had a low impact property and was poor in appearance and moldability, and was unsuitable as a wheel cover.

Comparative Example 2 40% by weight of the vinyl-based copolymer (A-2) obtained in Reference Example 1 and the polyamide (B-1) 60 obtained in Reference Example 2 were used without using the modified polyolefin (C). Melt kneading, injection molding, and property evaluation were carried out in the same manner as in Example 1 except that the weight% was used, and the results shown in Table 1 were obtained. The molded product obtained here had a low impact resistance and a poor appearance, and was unsuitable as a wheel cover.

Comparative Example 3 15% by weight of the vinyl copolymer (A-3) obtained in Reference Example 1, 20% by weight of the polyamide (B-2) obtained in Reference Example 2, obtained in Reference Example 3 Modified polyolefin (C-
2) Melt kneading, injection molding, and property evaluation were carried out in the same manner as in Example 1 except that the amount was 65% by weight, and the results shown in Table 1 were obtained. The molded product obtained here had low rigidity and weather resistance, and was poor in appearance and moldability, and was unsuitable as a wheel cover.

Examples 2 to 5 Molded articles obtained by melt-kneading and injection-molding the vinyl-based copolymer (A), polyamide (B) and modified polyolefin (C) in various kinds and blending amounts. As shown in Table 1, it was found that in each case, a wheel cover excellent in balance of rigidity, impact resistance, heat resistance, weather resistance, and moldability was obtained.

[0048]

[Table 1]

[0049]

EFFECT OF THE INVENTION A wheel cover molded from a resin composition comprising a vinyl-based copolymer, a polyamide and a modified polyolefin has a good balance of rigidity, impact resistance, heat resistance and weather resistance and is of practical value as a wheel cover for automobiles. It is expensive.

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Claims (1)

[Claims] 1. At least one vinyl-based monomer selected from the group consisting of (A) (a) aromatic vinyl-based monomer and (meth) acrylic acid ester-based monomer in an amount of 5 to 95% by weight. , (B) General formula (1) 5 to 95% by weight of the maleimide-based monomer (in the formula,
R1, R2 and R3 each represent hydrogen, halogen or a substituted or unsubstituted hydrocarbon having 1 to 20 carbon atoms. And (c) a vinyl-based copolymer obtained by polymerizing 0.05 to 50% by weight of another vinyl-based monomer copolymerizable with (a) and / or (b) above (B) a polyamide and (C) a modified polyolefin having at least one functional group selected from the group consisting of a carboxylic acid group, a carboxylic acid metal base and an acid anhydride group, (A) being 5 to 90% by weight,
3 to 90% by weight of (B) and 5 to 60% by weight of (C)
A wheel cover for an automobile, which is obtained by injection-molding a thermoplastic resin composition obtained by mixing at a ratio of.