JP3406033B2 - Resin composition for wheel cap - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition for automobile wheel caps which is excellent in light resistance, oil resistance, mechanical properties, heat resistance, and moldability.

[0002]

2. Description of the Related Art Polyamide resins are excellent in mechanical strength, oil resistance, heat resistance and the like, and are used in large amounts as one of the most representative engineering plastics. However, on the other hand, it has a drawback that properties such as dimensional stability, hygroscopicity, heat distortion resistance under high load, and impact resistance during drying are lower than those of other plastics.

Polystyrene is an inexpensive resin excellent in dimensional stability, electrical characteristics, molding processability and the like, and is used in large amounts in home electric appliances and daily necessities. However, the heat resistance and mechanical strength are not sufficient. Although alloys of polyamide resin and polystyrene have been studied as a resin that has both characteristics, polyamide resin and polystyrene are originally hard to be compatible with each other, and a simple blended product has excellent mechanical strength. Can't get
No material for practical use can be obtained.

As an attempt to improve the compatibility of polyamide and polystyrene, polystyrene is made into a copolymer of styrene and maleic anhydride and melt-kneaded with polyamide, and a copolymer of styrene and maleic anhydride is a compatibilizing agent. For example, a melt-kneaded mixture of polyamide and polystyrene has been proposed. (Japanese Patent Publication No. 61-056249 and U.S. Pat. No. 3,966,839) These materials have insufficient compatibility and poor mechanical properties, or have insufficient heat resistance and may be deformed when heat is applied. It had a defect that it was pyrolyzed if it stayed at a high temperature during molding.

In particular, the composition described in the above-mentioned US patent uses a styrene-maleic anhydride copolymer having a low molecular weight of 1,000 to 3,000 as a compatibilizing agent, so that the compatibility is poor. Enough, the dispersed particle size is quite large,
It is also estimated that the mechanical properties are inferior. The above-mentioned polyamide-polystyrene alloy has excellent performance, but cannot be used as a material for wheel caps due to its drawbacks of low heat resistance and low impact resistance. Wheel caps need materials that can withstand the heat of the brakes and the impact of a stone hit.

A resin composition composed of polyamide, polyphenylene ether and an elastomer was also known as a useful resin composition for wheel caps, but it has a drawback that it is strongly discolored by light and requires a thick coating. It was

[0007]

[Problems to be Solved by the Invention] A resin which suppresses rigidity reduction and dimensional change due to water absorption of polyamide and does not lack heat resistance of a composition of polyamide and polystyrene or a copolymer of polyamide and styrene and maleic anhydride. There has been a demand for a material for wheel caps that causes less discoloration.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies to achieve the above-mentioned objects, and as a result, have made a resin composition composed of polyamide and polystyrene, in which a dispersed phase has an average particle diameter of 5 μm or less and is finely dispersed in a matrix. It was found that the product has various excellent physical properties and is suitable as a resin composition for automobile wheel caps, and has completed the present invention.

Furthermore, a resin composition comprising a polyamide matrix, polystyrene and polyphenylene ether, wherein the average particle size of the dispersed phase is 5 μm or less contributes to the action of the polyphenylene ether as a compatibilizer. A more preferable resin composition for a wheel cap is provided. That is, the present invention relates to (A) polyamide 2
It contains 5 to 80% by weight, (B) polystyrene 10 to 50% by weight, (C) polyphenylene ether 5 to 40% by weight and (D) rubber polymer 0 to 30% by weight, and contains (B) component and (C). ) The weight ratio of the components is in the range of 80/20 to 30/70, and the total amount of the (B) component and the (C) component is 20 to 7.
0% by weight, and the component (A) further comprises a continuous phase (B).
Component, by which the component (C) and (D) component is to form a dispersion phase, a particular range the resin composition of each component ratio average particle size of the dispersed phase is 5μm or less, more desirably wheel A resin composition for a cap is provided.

The polyamide used as the component (A) in the present invention has an amide bond {--NH in the polymer main chain.
Any material that has -C (= 0)-} and can be heated and melted can be used. Typical examples are 4-nylon, 6-nylon, 6,6.
-Nylon, 12-nylon, 6,10-nylon,
6,6T-nylon (ε-caprolactam / hexamethylenediamine / terephthalic acid), 66,6T-nylon (hexamethylenediamine / adipic acid / terephthalic acid), 66,6I-nylon (hexamethylenediamine / adipic acid / isophthalic acid) ), 66,6T, 6I-nylon (hexamethylenediamine / adipic acid / terephthalic acid / isophthalic acid), polyamide from adipic acid and metaxylylenediamine, adipic acid and azelaic acid, and 2,2'-bis (p- Examples thereof include polyamides from aminocyclohexyl) -propane, polyamides from terephthalic acid and 4,4′-diaminodicyclohexylmethane, and copolymerized nylons thereof. Among these,
It is preferable to use 6-nylon, 6,6-nylon, 6-6,6 copolymer nylon, 66,6I-nylon alone or in combination.

The polystyrene used as the component (B) in the present invention is a homopolymer of a styrene compound,
An impact-resistant polystyrene obtained by grafting a styrene compound on a copolymer of two or more styrene compounds and a rubber-like polymer can be mentioned. The styrene compound is represented by the general formula (1)

[0012]

[Chemical 1]

(Wherein R represents hydrogen, lower alkyl or halogen, Z is selected from the group consisting of vinyl, hydrogen, halogen and lower alkyl, and p is an integer of 0 to 5) Means Specific examples thereof include styrene, α-methylstyrene, 2,4-dimethylstyrene, monochlorostyrene, p-methylstyrene, p-tert-butylstyrene, ethylstyrene and the like. Examples of the rubbery polymer include conjugated diene rubbers, rubbers obtained by hydrogenating a part or all of conjugated diene rubbers, ethylene-propylene copolymer rubbers, and the like. The method for producing the styrene resin of the present invention is not limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization well known to those skilled in the art may be used.

The polyphenylene ether used as the component (C) in the present invention is represented by the following general formula (2).

[0015]

[Chemical 2]

(Wherein R ₁ , R ₂ , R ₃ and R ₄ represent the same or different residues such as alkyl group, aryl group, halogen and hydrogen, and n represents the degree of polymerization). It is a polymer composed of repeating units. Specific examples thereof include poly (2,6-dimethyl-1,4-phenylene) ether and poly (2-methyl-6-ethyl-phenylene).
Ether, poly (2,6-diethyl 01,4-phenylene) ether, poly (2-ethyl-6-npropyl-
1,4-phenylene) ether, poly (2-methyl-6)
-N-butyl-1,4-phenylene) ether, poly (2
-Ethyl-6-isopropyl-1,4-phenine) ether, poly (2-methyl-6-chloro-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1,4-phenylene) Examples thereof include homopolymers such as ether and poly (2-methyl-6-chloroethyl-1,4-phenylene) ether, and copolymers composed of repeating units thereof. The degree of polymerization of these polyphenylene ethers, both homopolymers and copolymers, is 0 at an intrinsic viscosity [η] (chloroform solution, 30 ° C).
Those in the range of 30 to 1.5, preferably 0.35 to 1.0 are preferably used. Furthermore, for example, JP-A-2-27
It also includes polyphenylene ether modified with a compound having a carbon-carbon double bond, which is described in JP-A-6823, JP-A-63-108059, JP-A-59-59724 and the like.

The rubber-like polymer used as the component (D) in the present invention includes a styrene-butadiene block copolymer, a hydrogenated styrene-butadiene block copolymer, a styrene-isoprene block copolymer, and a hydrogenated styrene-polymer. Isoprene block copolymer, ethylene-propylene elastomer, ethylene-based ionomer resin,
Core / shell polymers composed of a rubber-like core and a shell of a non-rubber-like polymer, and in particular, a styrene-butadiene block copolymer and a styrene-butadiene block copolymer in which a part or all of the butadiene moiety is hydrogenated. preferable. Further, it is also possible to use those obtained by modifying these rubber-like polymers with an epoxy compound, an unsaturated carboxylic acid and its derivative, or the like.

(A) polyamide in the composition of the present invention,
(B) polystyrene, (C) polyphenylene ether,
The composition ratio of the rubber-like polymer (D) is based on the total amount of the above four components, the component (A) is 25 to 80% by weight, preferably 35 to 70% by weight, and the component (B) is 10 to 50%. % By weight, preferably 15-40% by weight, 5-40% by weight of component (C), preferably 10-30% by weight, 0-3 of component (D).
It is in the range of 0% by weight, preferably 5 to 20% by weight. In the present invention, each component has the above-mentioned composition ratio,
When the content of the component (A) is less than 25% by weight, it is difficult to form the polyamide into a continuous phase, and the oil resistance, which is a feature of the polyamide,
This is because the moldability and the like are impaired. On the other hand, when the content of the component (A) exceeds 80% by weight, the drawbacks of polyamide, such as water resistance and dimensional properties, are not improved, which is not preferable. The weight ratio of the components (B) and (C) is 80/20 to 30/70.
The range is preferably 70/30 to 40/60. When the ratio of the component (C) is less than this range, heat resistance and impact resistance are poor, and when the ratio of the component (C) is more than this range, discoloration due to ultraviolet rays is large, which is not preferable.

The discoloration of a resin composition composed of polyamide, polystyrene and polyphenylene ether due to ultraviolet light causes the polyphenylene ether, which is the causative agent of the discoloration, to be different from the discoloration of the resin composition composed of polyamide and polyphenylene ether due to the ultraviolet light. It has less discoloration than when it is diluted, and has favorable performance as a material for wheel caps.

The rubber-like polymer is preferably present for improving impact resistance, and it may be blended if necessary, but blending in an amount of 30% by weight or more unfavorably lowers rigidity and heat resistance. The composition of the present invention is required that the component (A) forms a continuous phase and the components (B), (C) and (D) form a dispersed phase, and the volume average particle diameter of the dispersed phase. Needs to be 5 μm or less. The particles of the dispersed phase preferably have a volume average particle diameter of 0.1 to 3 μm. The particle size of the dispersed particles is a volume average particle size, and a specific measuring method is as follows.

The composition of the present invention having polyamide as a matrix was dissolved in formic acid, and the refractive index was 1. with a laser diffraction particle size distribution analyzer SALD2000 manufactured by Shimadzu Corporation.
It is measured under the condition of 70-0.20i. The 50% cumulative diameter of the obtained volume-based particle size distribution is the average particle diameter referred to in the present invention. Next, a general method for producing the composition of the present invention will be described. Of course, other production methods can be used as long as the above-mentioned conditions are satisfied.

The composition of the present invention comprises (A) polyamide,
(B) polystyrene, (C) polyphenylene ether,
It is obtained by melt-mixing the rubber-like polymer (D). In the melt mixing, a compound having a carboxylic acid group, an acid anhydride group, an epoxy group, an amino group or a hydroxyl group, and a compound having a carbon-carbon double bond or triple bond at the same time in the molecule are used as a modifier. Is preferred.
Specific examples of these compounds include maleic acid, fumaric acid, chloromaleic acid, cis-4-cyclohexene-
1,2-dicarboxylic acids and their acid anhydrides, esters, half-alkyl esters, amides, imides, citric acid,
Examples thereof include malic acid and the like, and α, β-unsaturated dicarboxylic acid and its derivative, particularly maleic acid and maleic anhydride are particularly preferable. These compounds may be used alone or in combination of two or more kinds. A carboxylic acid group in the molecule, acid anhydride groups, added pressure of an epoxy group, an amino group or a compound having a hydroxyl group, with respect to the (B), the total amount 100 parts by weight of component (C), 0.05 It is desirable to select in the range of 3 to 3 parts by weight, preferably 0.1 to 1 part by weight. This addition amount is 0.05
If it is less than 1 part by weight, the particle size of the dispersed phase becomes large, which is not preferable in terms of physical properties. Even if an addition amount of more than 3 parts by weight is used, the effect is not increased, and problems such as decomposition and discoloration occur. It is also economically disadvantageous. The component (B) polystyrene and the component (C) polyphenylene ether are
It is possible to use those which have been melt-mixed in advance, but it is preferable to carry out melt-mixing when obtaining the composition of the present invention from the viewpoint of simplification of the process.

As the kneading method, all the components may be kneaded at once, or the component (C) is pre-kneaded together with the modifier and then the components (A), (B) and (D) are kneaded. The component (B) and the component (C) together with the modifier, and then the components (A) and (D) are kneaded together, the component (B), the component (C) together with the modifier, and A method in which the component (A) is kneaded after the component (D) is pre-kneaded may be used.

The temperature and time for melt-kneading may be set arbitrarily depending on the type of polyamide used and the compounding ratio, but it is usually 240 to 360 ° C., preferably 280 to 280.
A temperature in the range of 340 ° C. and a kneading time of 0.1 to 10 minutes, preferably about 0.3 to 3 minutes are suitable. As the melt-kneading device, a single-screw extruder, a twin-screw extruder, a kneader, a roll or the like can be used, but an extruder, particularly a twin-screw extruder is particularly suitable.

The composition of the present invention includes the entire composition 1 if desired.
In the range of 0 to 50 parts by weight with respect to 00 parts by weight, other polymers, various stabilizers, plasticizers, lubricants, flame retardants, or particulate or fibrous inorganic fillers, glass fibers, carbon fibers,
Various whiskers and the like can be added.

[0026]

EXAMPLES Next, the present invention will be specifically described with reference to Examples. The following examples are merely illustrative and do not limit the content of the present invention. The components used in the examples and comparative examples are as follows. Component (A): Polyamide A-1, ηr = 2.01 (95.5% sulfuric acid, 25 ° C.), 6,6-nylon A-2; ηr = 2.45 (95.5% sulfuric acid, 25 ° C.) 6-nylon (B) component; polystyrene B-1; polystyrene homopolymer (Asahi Kasei Co., Ltd.)
Manufactured by Asahi Kasei Polystyrene 685) B-2; impact-resistant polystyrene (C) component containing 12% of partially hydrogenated polybutadiene in which 30% of all double bonds of polybutadiene are hydrogenated; polyphenylene ether C-1; specific Poly (2,6-dimethyl-1,4-phenylene) ether C-2 having a viscosity of 0.38 (30 ° C. in chloroform); poly (having an intrinsic viscosity of 0.50 (30 ° C. in chloroform) 2,6-Dimethyl-1,4-phenylene) ether (D) component: rubbery polymer styrene-butadiene block copolymer (Tufpren 200, manufactured by Asahi Kasei Kogyo Co., Ltd.) Further, regarding the obtained resin composition, It was evaluated according to the following method.

Injection molding machine (IS80 manufactured by Toshiba Machine Co., Ltd.)
C, a cylinder temperature of 280 ° C., a molding cycle of 1 minute) to prepare a test piece, and the following physical property measurements and tests were carried out. (1) Photochromic property (ΔYI) Light exposure at 313 nm was performed, the YI value of the test piece before and after the light exposure was measured by a colorimeter, and the difference ΔYI was evaluated.
The smaller the value of ΔYI, the better the light discoloration resistance (yellowing degree). (2) Izod impact strength (IZOD) ASTM D-256, notched (3) Heat distortion temperature (HDT) ASTM D-648, 4.6 kg / cm ² load (4) Dispersion particle size Laser method It was measured with a granulometer.

[0028]

Example 1 16 parts by weight of component (B-1), (C-1)
24 parts by weight of components and 0.16 parts by weight of maleic anhydride as a modifier are supplied from the top (previous stage) of a co-rotating twin-screw extruder having a screw diameter of 25 mm, and 50 parts by weight of component (A-1). , (D) 10 parts by weight, (F ) 0.15 parts by weight of tri (2,4-ditertiarybutylphenyl) phosphite (Irgafoss 168 manufactured by Ciba-Geigy) as a stabilizer, and 0.15 parts by weight of zinc oxide. Parts, 0.15 parts by weight of zinc sulfide, 0.5 parts by weight of titanium oxide (E) as a colorant, and 0.0015 parts by weight of carbon are supplied from the middle of the extruder (middle stage) to obtain 300 ° C. and 300 rp.
Extrusion kneading was carried out at m to obtain composition pellets. Then, various tests were conducted by the above-mentioned method. The results are shown in Table 1.

[0029]

Examples 2 to 4, Comparative Examples 1 to 4 Components (A) to (D)
Example 1 was repeated except that the composition shown in Table 1 was changed .

[0030]

Examples 6 to 8 Components (A) to (D) have the compositions shown in Table 2, and (E) 3 parts by weight of titanium oxide as a coloring agent and 0.05 parts by weight of carbon are used. The same procedure as in Example 1 was performed. The results are shown in Table 2.

[0031]

Example 9 Except that the component (C) was replaced with the component (C-1) and maleic anhydride as a modifier was used in an amount of 0.05 parts by weight.
The same procedure as in Example 8 was performed.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

EFFECT OF THE INVENTION The resin composition of the present invention is excellent in heat resistance, impact resistance, oil resistance, molding processability and light resistance, and is capable of releasing molded products.
It is a material for automobile wheel caps that is free from dimensional changes and rigidity reduction when absorbing water.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08K 5/526 C08L 21/00 C08L 21/00 25/00 25/00 71/12 71/12 B60B 7/00 S

Claims (5)

(57) [Claims] 1. A resin composition comprising a polyamide matrix, polystyrene and polyphenylene ether, wherein the average particle size of the dispersed phase is 5 μm or less. 2. (A) 25 to 80% by weight of polyamide,
(B) 10 to 50% by weight of polystyrene, (C) 5 to 40% by weight of polyphenylene ether and (D) 0 to 30% by weight of a rubber-like polymer, and the weight ratio of the (B) component and the (C) component is In the range of 80/20 to 30/70, the total amount of the component (B) and the component (C) is 20 to 70% by weight, and the component (A) is a continuous phase, the component (B) and the component (C). The component) and the component (D) form a dispersed phase, and the average particle size of the dispersed phase is 5 μm or less. 3. (E) Titanium oxide and
/ Or carbon is the total amount of components (A) to (D) 100
The content should be 50 parts by weight or less with respect to parts by weight.
An automobile wheel key according to claim 1 or 2, characterized in that
Resin composition for cap. 4. The stabilizer of (F) is tri (2,4-di).
Tertiary butyl phenyl) phosphite, zinc oxide
And at least one selected from the group consisting of zinc sulfide,
50 per 100 parts by weight of the total amount of components (A) to (D)
When the content is less than or equal to parts by weight, or when the component (E) is contained,
The total amount of (E) and (F) is the total amount of components (A) to (D).
Contain within the range of 50 parts by weight or less with respect to 100 parts by weight
Automatic according to any one of claims 1 to 3, characterized in that
Resin composition for car wheel caps. 5. (E) and / or (F) of the extruder
Addition from the middle, melt kneading, characterized by
Resin composition for automobile wheel cap according to 3 or 4
object.