JPH079476A - Car wheel cover - Google Patents

Abstract

PURPOSE:To obtain a car wheel cover superior in coating adhesion by injection molding a composition composed of a specific vinyl copolymer containing a maleimide monomer as a copolymerizing compound, a polyamide added with a barium stearate, and a modified polyolefin. CONSTITUTION:A polyamide composition (A) is prepared by adding 0.02-1.0 pts.wt. barium stearate per 100 pts.wt. of polyamide. A vinyl copolymer (B) is prepared by copolymerizing 40-75wt.% at least one of aromatic vinyl monomer or (meth)acrylic monomer, 25-60wt.% maleimide monomer shown by a formula (In the formula, R1-R3 represent hydrogen, halogen, or C1-20 hydrocarbon.), and 0.5-10wt.% another vinyl copolymer that can copolymerize with at least the aforesaid monomer. A modified polyolefin (C) has carboxylic acid group, carboxylic acid metallic salt group, or anhydride group. A composition containing A by 10-80wt.% and B, C each by 10-50wt.% is injection molded.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to polyamide and vinyl which have good coating adhesion when coated with various paints, and have excellent low temperature impact resistance, weather resistance, heat resistance, high rigidity and appearance. TECHNICAL FIELD The present invention relates to a resin-made automobile wheel cover mainly composed of a system copolymer and a modified polyolefin.

[0002]

2. Description of the Related Art In recent years, from the viewpoints of energy saving and low cost, the coating of automobile wheel covers has been undertaken without the undercoat coating, and only the top coating is being applied. Has been. Typical materials currently used for automobile wheel covers are alloys of polyamide and modified polyolefin, modified polyphenylene ether, glass or filler reinforced polyamide, alloys of polyamide and polyphenylene ether, and the like.

However, although an alloy of polyamide and modified polyolefin (for example, Japanese Patent Publication No. 55-44108) is excellent in impact resistance, it has problems in coating adhesion and heat resistance. The modified polyphenylene ether is excellent in impact resistance, but has problems in thinner resistance, weather resistance, and heat resistance in the paint. Glass or filler reinforced polyamide is weather resistant,
It excels in heat resistance and high rigidity, but has problems with coating film adhesion and appearance. A combination of polyamide, polyphenylene ether, and styrene-butadiene-styrene block copolymer (for example, Japanese Patent Laid-Open No. 61-146433) has good performance as a wheel cover for automobiles and good adhesion to coating film, but weather resistance. However, there is a problem that weather resistance discoloration after coating is remarkable. Polyamide and imidized ABS
(For example, JP-A-63-179957)
(Patent Publication) has excellent impact resistance and weather resistance after painting, but has problems in heat resistance and rigidity. On the other hand, alloys of styrene-maleimide copolymer, polyamide and modified polyolefin
It is known that, for example, Japanese Patent Laid-Open No. 62-59647 discloses a poor balance between impact resistance and coating adhesion.

[0004]

As described above, in the prior art, no material having both impact resistance and coating adhesion can be found, but in recent years, in automobile wheel covers, only top coating is applied, It has become an issue to provide a wheel cover for automobiles which is more excellent in coating adhesion than ever before while maintaining the impact resistance of the wheel cover for automobiles such as diversification thereof and coating with various paints.

[0005]

In view of the above circumstances, the inventors of the present invention have investigated a wheel cover for automobiles having excellent coating adhesion, and as a result, found that a wheel cover for automobiles obtained by a specific polyamide alloy composition was obtained. The inventors have found that the above problems can be solved and arrived at the present invention. That is, the present invention provides (A) a polyamide composition obtained by adding 0.02 to 1.0 part by weight of barium stearate to 100 parts by weight of polyamide, (B) (a) an aromatic vinyl-based monomer, and (b) (Meth) 40 to 75% by weight of at least one vinyl monomer selected from the group consisting of acrylic acid ester monomers, (b) the following general formula (I)

[0006] (Wherein R ₁ , R ₂ and R ₃ are each hydrogen, halogen,
It represents a substituted or unsubstituted hydrocarbon having 1 to 20 carbon atoms. 25 to 60% by weight of a maleimide-based monomer represented by
And (C) a vinyl-based copolymer obtained by copolymerizing 0.05 to 10% by weight of another vinyl-based monomer copolymerizable with (A) and / or (B) above, and (C) a carvone. A modified polyolefin having at least one functional group selected from the group consisting of an acid group, a metal carboxylate group and an acid anhydride group is used, wherein (A) is 40 to 80% by weight and (B) is 10 to 50% by weight. , (C) are mixed at a ratio of 10 to 50% by weight, and a thermoplastic resin composition obtained by injection molding is injection-molded to provide a wheel cover for an automobile.

The polyamide composition (A) used in the present invention is obtained by adding barium stearate to polyamide. As the polyamide, ε-caprolactam, ω
-Polyamides obtained by ring-opening polymerization of lactams such as dodecalactam, polyamides derived from amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, ethylenediamine, tetramethylenediamine hexamethylenediamine , Undecamethylenediamine, dodecamethylenediamine, 2,2
4- / 2,4,4-trimethylhexamethylenediamine, 1,3- and 1,4-bis (aminomethyl) cyclohexane, bis (4,4'-aminocyclohexyl)
Aliphatic, alicyclic and aromatic diamines such as methane, meta and para-xylylenediamine and adipic acid, suberic acid, sebacic acid, dodecanedioic acid, 1,3- and 1,4
A polyamide derived from an aliphatic, alicyclic or aromatic dicarboxylic acid such as cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid or dimer acid, and a copolyamide or mixed polyamide thereof. Of these, polycaproamide (nylon 6), polyhexamethylene dipamide (nylon 66) and copolyamides thereof (nylon 6/66) are preferable, and nylon 6 is particularly preferable. And to 100 parts by weight of at least one polyamide selected from these, 0.02-1.0 parts by weight of barium stearate, preferably 0.03-0.
5 parts by weight are added. If the amount of barium stearate added is less than 0.02 parts by weight, the coating film adhesion and moldability will decrease, and if it exceeds 1.0 parts by weight, the toughness will rather deteriorate and the appearance of the molded product will deteriorate, resulting in an automobile. The function as a wheel cover for vehicles is impaired. Barium stearate is added at the time of polymerization of polyamide, or polyamide,
It is added when the vinyl copolymer (B) and the modified polyolefin (C) are melt-kneaded. 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,
A polyamide having a relative viscosity (dissolving 1 g of polymer in 100 ml of 98% concentrated sulfuric acid at 25 ° C) in the range of 2.0 to 5.0 can be arbitrarily selected according to the purpose. The same kind of polyamide as above may be used. In the vinyl copolymer (B) used in the present invention, the vinyl monomer (a) means styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene, vinyltoluene, p-chlorostyrene. Aromatic vinyl monomers such as
And methyl methacrylate, ethyl methacrylate, -t-butyl methacrylate, cyclohexyl methacrylate,
At least one selected from the group consisting of (meth) acrylic acid ester-based monomers such as phenyl methacrylate, methyl acrylate, ethyl acrylate, and propyl acrylate.
It is a type of vinyl monomer.

Among the above vinyl-based monomers (a), styrene, α-methylstyrene, p-methylstyrene and methyl methacrylate are preferable, and styrene is particularly preferable. Further, the maleimide-based monomer (B) has a general formula
There is no particular limitation as long as it satisfies (I), but specific examples include maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, Nt-
Butyl maleimide, N-phenyl maleimide, N-m-
Methylphenylmaleimide, N-o-methylphenylmaleimide, Np-methylphenylmaleimide, N-cyclohexylmaleimide, N-o-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide,
N-p-hydroxyphenylmaleimide, N-o-methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, Np-methoxyphenylmaleimide, N-
o-chlorophenyl maleimide, Nm-chlorophenyl maleimide, Np-chlorophenyl maleimide, N
Examples thereof include -o-carboxyphenylmaleimide, Np-carboxyphenylmaleimide, Nm-erboxoxyphenylmaleimide, dichloromaleimide and N-naphthylmaleimide.

Among these, N-phenylmaleimide, N-cyclohexylmaleimide, Nt-butylmaleimide, N-isopropylmaleimide and Nm-
Methylphenylmaleimide is preferable, and N-phenylmaleimide is particularly preferable. These can be used alone or in combination of two or more. Vinyl monomer
(C) is not particularly limited as long as it is a copolymerizable with (a) and / or (b) and is a vinyl-based monomer other than (a) and / or (b), and examples thereof include acrylonitrile and methacrylonitrile. Examples thereof include vinyl cyanide-based monomers such as nitrile, acrylic acid, methacrylic acid, and maleic anhydride. Of these, maleic anhydride is particularly preferable.

In the polymerization of the vinyl copolymer (B), the proportion of the monomers (a), (b) and (c) is 40 to 75% by weight, preferably 45 to 60% by weight. ,
(B) is 25 to 60% by weight, preferably 40 to 55% by weight, and (c) is 0.05 to 10% by weight, preferably 0.1 to 5% by weight. If (a) is less than 40% by weight or more than 75% by weight, (B) is less than 25% by weight or more than 60% by weight, or (C) is 0.05.
If the content is less than 10% by weight or more than 10% by weight, the resulting resin composition is inferior in coating film adhesion, mechanical properties, thermal stability and melt flowability. In particular, if (a) is less than 40% by weight, the adhesion of the coating film decreases, and if it exceeds 75% by weight, the impact resistance and moldability are rather poor, which is not preferable.

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 copolymer, ethylene / maleic anhydride copolymer, ethylene / propylene / maleic anhydride copolymer, ethylene-g-maleic anhydride copolymer ("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.
Of these, ethylene / propylene-g-maleic anhydride copolymer is preferred. It is also possible to use two or more of these modified polyolefins in combination.

The modified polyolefin (C) is usually produced by 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. The polyamide composition (A) obtained by adding barium stearate to the thermoplastic resin composition of the present invention, the vinyl copolymer (B) and the modified polyolefin (C) have a compounding ratio (A) of 40 to 8
0% by weight, preferably 45 to 60% by weight, (B) is 10
-50% by weight, preferably 20-40% by weight, and (C) is 10-50% by weight, preferably 20-40% by weight. If the content of (A) is less than 40% by weight, the rigidity and heat resistance will be poor, and if the content of (A) exceeds 80% by weight, the coating film adhesion and impact resistance will be poor, such being undesirable. (B) is 10
If it is less than 50% by weight, the adhesion of the coating film is poor and (B) is 50% by weight
If it exceeds the range, the moldability and the appearance of the molded product deteriorate, which is not preferable. If (C) is less than 10% by weight, impact resistance is poor, and if (C) is more than 50% by weight, coating film adhesion, rigidity, and
Moldability and heat resistance are 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 polyamide composition (A), the vinyl copolymer (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 a sufficient kneading ability is obtained. Various methods such as a method of melt-kneading with a certain single-screw or multi-screw extruder, a method of melt-kneading with a Banbury mixer, or a rubber roll machine can be adopted. In addition, the polyamide composition (A) and the vinyl copolymer (B), the polyamide composition (A) and the modified polyolefin (C), the vinyl copolymer (B) and the modified polyolefin (C), and the like are pre-kneaded in advance. Alternatively, it is possible to adjust the mixture ratio to a predetermined value and then knead the mixture.

The thermoplastic resin composition of the present invention comprises a polyamide composition (A) obtained by adding barium stearate, a vinyl copolymer (B) and a modified polyolefin (C).
In addition to organic pigments, inorganic pigments, organic dyes, inorganic dyes, antioxidants such as hindered phenols, flame retardants, heat stabilizers, lubricants, plasticizers, antistatic agents, and fillers such as glass fibers. The agent and the like can be added at any stage according to a conventional method. The automobile wheel cover of the present invention is manufactured by known injection molding. Further, the size and shape of the wheel cover are arbitrarily selected according to the type of automobile.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Toshiba IS is molding wheel covers for automobiles.
Using a 630CN injection molding machine, the mold was a 14-inch automobile wheel cover mold having a hot runner type center gate. Cylinder setting temperature was 290 ° C. and hot runner setting temperature was 300 ° C.

The coating film adhesion described in Examples and Comparative Examples was measured by the following method. A wheel cover for automobiles was applied once using an acrylic / urethane-based paint and baked at a temperature of 80 ° C. for 30 minutes. The thickness of the coating film was 20 μm. 2 painted car wheel covers
After leaving it for a day, with a blade of a cutter knife, 100 lines of 2 mm x 2 mm score line that reaches the base material are made in the coating film, and Nichiban-made cellophane adhesive tape of 24 mm width and 60 mm length is stuck on the score line. Hold one end of the tape, about 45
Peel at a stretch with a pulling angle of °. The measured value was the coating film residual rate (number of squares). The maximum value is 100%. There were two measurement sites, the center part (center gate part) and the outer peripheral part of the automobile wheel cover. <Reference Example 1> A-1: ε-caprolactam was polycondensed to obtain a polyamide 6 having a concentrated sulfuric acid relative viscosity of 2.7. A-2: 0.4 part by weight of barium stearate was dry blended with A-1. <Reference Example 2> B-1: 50 parts of styrene and 0.5 part of azobisisobutyronitrile were charged in a polymerization tank, the temperature was adjusted to 80 ° C, and with stirring, 50 parts of N-phenylmaleimide and maleic anhydride. 8 parts of a solution consisting of 5 parts and 80 parts of methyl ethyl ketone
It was charged at a constant speed over time. Then, the temperature was raised to 90 ° C. and kept for 2 hours. A transparent and viscous solution was obtained, and the solvent was removed to obtain a vinyl-based copolymer (B-1). B-2: A polymerization tank was charged with 50 parts of styrene and 0.5 part of azobisisobutyronitrile, the temperature was adjusted to 80 ° C., and a solution consisting of 50 parts of N-phenylmaleimide and 80 parts of methyl ethyl ketone was stirred while stirring. It was charged at a constant speed for 8 hours. Then, the temperature was raised to 90 ° C. and kept for 2 hours. A transparent and viscous solution was obtained, and the solvent was removed to obtain a vinyl-based copolymer (B-2). B-3: 60 parts of styrene and 0.5 part of azobisisobutyronitrile were charged in a polymerization tank, and the temperature was adjusted to 80 ° C., while stirring, 40 parts of N-phenylmaleimide, 5 parts of maleic anhydride and 80 parts of methyl ethyl ketone. 8 parts solution
It was charged at a constant speed over time. Then, the temperature was raised to 90 ° C. and kept for 2 hours. A transparent and viscous solution was obtained, and the solvent was removed to obtain a vinyl-based copolymer (B-3). B-4: 30 parts of styrene and 0.5 part of azobisisobutyronitrile were charged in a polymerization tank, and the temperature was adjusted to 80 ° C., while stirring, 70 parts of N-phenylmaleimide, 0.5 part of maleic anhydride and A solution consisting of 80 parts of methyl ethyl ketone was charged at a constant rate for 8 hours. Then, the temperature was raised to 90 ° C. and kept for 2 hours. A transparent and viscous solution is obtained, and by removing the solvent, the vinyl copolymer (B-4)
Got B-5: 200 parts of water and 0.3 part of polyvinyl alcohol (suspension stabilizer) having a saponification degree of 80% were charged in a polymerization tank,
Next, 45 parts of styrene and 45 of N-phenylmaleimide
Parts, acrylonitrile 10 parts, maleic anhydride 1 part and azoisobutyronitrile 0.5 parts were charged and stirred at high speed to obtain a suspension state. 6 at 80 ℃ while maintaining suspension
Polymerization was continued for 1 hour at 90 ° C to obtain a granular vinyl copolymer (B-5). Reference Example 3 C-1: α, α′-bis-t dissolved in a small amount of acetone based on 100 parts by weight of an ethylene / propylene copolymer composed of 70 mol% of ethylene and 30 mol% of propylene.
-Butylperoxy-p-diisopropylbenzene 0.
Ethylene / propylene-g-maleic anhydride copolymer (C- 1) was obtained.

Example 1 56 parts by weight of the polyamide composition (A-2) obtained in Reference Example 1 and the vinyl copolymer (B-1) obtained in Reference Example 2
22 parts by weight, modified polyolefin obtained in Reference Example 3
After 22 parts by weight of (C-1) was dry blended using a Henschel mixer, it was fed to the hopper of a twin-screw extruder,
The mixture was melt-kneaded and pelletized under the conditions of a cylinder temperature of 300 ° C. and a screw rotation speed of 200 rpm. 9 of these pellets
After vacuum drying at 0 ° C. for 24 hours, an automobile wheel cover was injection-molded, allowed to stand for 1 day, and then painted. When the coating adhesion of this automobile wheel cover was evaluated, the coating adhesion between the center gate and the outer peripheral portion was as shown in Table 1. The automobile wheel cover using the resin composition obtained here had excellent coating film adhesion.

[0019]

[Table 1]

Comparative Example 1 Including barium stearate as the component (A) (A-
Melt kneading, injection molding, coating and coating film adhesion evaluation were carried out in exactly the same manner as in Example 1 except that 2) was not used and (A-1) not added was used, and the results shown in Table 1 were obtained. The automobile wheel cover obtained here was inferior in coating film adhesion.

Example 2 56 parts by weight of the polyamide composition (A-2) obtained in Reference Example 1 and the vinyl copolymer (B-3) obtained in Reference Example 2
22 parts by weight, modified polyolefin obtained in Reference Example 3
Melt kneading, injection molding, coating and coating film adhesion evaluation were carried out in the same manner as in Example 1 except that 22 parts by weight of (C-1) was dry blended using a Henschel mixer, and the results shown in Table 1 were obtained. . The automobile wheel cover obtained here had excellent coating film adhesion.

Comparative Example 2 Melt kneading, injection molding, coating and coating adhesion evaluation were carried out in the same manner as in Example 1 except that (B-4) was used as the component (B), and the results shown in Table 1 were obtained. . The automobile wheel cover obtained here was inferior in coating film adhesion. Example 3 50 parts by weight of the polyamide composition (A-2) obtained in Reference Example 1 and the vinyl-based copolymer (B-1) obtained in Reference Example 2
32 parts by weight, modified polyolefin obtained in Reference Example 3
(C-1) Melt kneading, injection molding, coating and evaluation of coating film adhesion were carried out in the same manner as in Example 1 except that 18 parts by weight of the mixture was dry blended using a Henschel mixer, and the results shown in Table 1 were obtained. . The automobile wheel cover obtained here had excellent coating film adhesion.

Comparative Example 3 37 parts by weight of the polyamide composition (A-2) obtained in Reference Example 1 and the vinyl copolymer (B-1) obtained in Reference Example 2
55 parts by weight, modified polyolefin obtained in Reference Example 3
(C-1) Melt kneading, injection molding, coating and coating film adhesion evaluation were carried out in exactly the same manner as in Example 1 except that 8 parts by weight was dry blended using a Henschel mixer, and the results shown in Table 1 were obtained. . Only a wheel cover for automobiles was obtained, which was inferior in moldability and was inferior in appearance with flow marks.
Moreover, the coating adhesion was also poor.

Example 4 Except that the vinyl copolymer (B-5) obtained in Reference Example 2 was used, melt kneading, injection molding,
The coating and coating adhesion were evaluated and the results shown in Table 1 were obtained. The automobile wheel cover obtained here had excellent coating film adhesion. Comparative Example 4 Melt kneading, injection molding, and the same procedure as in Example 1 except that the vinyl copolymer (B-2) obtained in Reference Example 2 was used.
The coating and coating adhesion were evaluated and the results shown in Table 1 were obtained. Only a wheel cover for automobiles was obtained, which was inferior in moldability and was inferior in appearance with flow marks. Moreover, the coating adhesion was also poor.

[0025]

EFFECT OF THE INVENTION A polyamide composition containing barium stearate, a vinyl-based copolymer in which maleimide is copolymerized, and a resin composition in which a modified polyolefin is alloyed in a specific blending amount are injection-molded to obtain coating adhesion. It is possible to obtain a dramatically improved automobile wheel cover.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29L 31:30

Claims (2)

[Claims] 1. A polyamide composition obtained by adding 0.02 to 1.0 part by weight of barium stearate to 100 parts by weight of (A) polyamide, (B) (a) an aromatic vinyl-based monomer and (b) (Meth) 40 to 75% by weight of at least one vinyl monomer selected from the group consisting of acrylic acid ester monomers, (b) the following general formula (I) (Wherein R ₁ , R ₂ and R ₃ are each hydrogen, halogen,
It represents a substituted or unsubstituted hydrocarbon having 1 to 20 carbon atoms. 25 to 60% by weight of a maleimide-based monomer represented by
And (C) a vinyl-based copolymer obtained by copolymerizing 0.05 to 10% by weight of another vinyl-based monomer copolymerizable with (A) and / or (B) above, and (C) a carvone. A modified polyolefin having at least one functional group selected from the group consisting of an acid group, a metal carboxylate group and an acid anhydride group is used, wherein (A) is 40 to 80% by weight and (B) is 10 to 50% by weight. , (C) is mixed at a ratio of 10 to 50% by weight, and a thermoplastic resin composition obtained by injection molding is used for injection molding. 2. A polyamide composition obtained by adding 0.02 to 1.0 part by weight of barium stearate to 100 parts by weight of nylon 6 (A). (B) (a) Styrene, (b) N-phenylmaleimide, and (c) 0.05 to 10% by weight of another vinyl-based monomer copolymerizable with the above (a) and / or (b). Polymerized vinyl copolymer and (C) ethylene / propylene-maleic anhydride graft copolymer, (A) 45 to 60% by weight, (B) 20
A wheel cover for an automobile obtained by injection molding a thermoplastic resin composition obtained by mixing -40% by weight and (C) 20-40% by weight.