JPH06322264A - Resin composition for bicycle wheel - Google Patents

Abstract

PURPOSE:To provide a resin compsn. for bicycle wheel which is excellent in strengths, stiffness, impact resistance, weld characteristics, appearance, and moldability under equilibrium in the air. CONSTITUTION:The compsn. is prepd. by compounding 30-85 pts.wt. polyamide component comprising a blend of at least two polyamides selected from the group consisting of polyamide 6, copolyamide 66/6, and polyamide 66 or comprising copolyamide 66/6 alone, 0-20 pts.wt. olefin elastomer, 1-20 pts.wt. modified olefin elastomer, and 15-60 pts.wt. glass fiber (the total amt. being 100 pts.wt.) and has a crystallization temp. of 175-220 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin composition for a bicycle wheel, which is excellent in strength, rigidity, impact resistance, weld characteristics and appearance.

[0002]

2. Description of the Related Art Conventionally, a bicycle wheel portion, that is, a spoke portion and a rib portion have been made of a metal material. However, in recent years, there has been a strong demand for fashionability. In addition, a wheel made of a resin that allows free design of the wheel has come to be partially used.

The required performance of a bicycle wheel is such that it has a large load strength / rigidity that does not deform even if a person rides it, sufficient impact resistance that it does not crack even when subjected to a sudden impact, and the amount of mud adhered. It is necessary to have a high gloss of the surface of the wheel, which is necessary to reduce the amount of oil.

Conventionally, polyamide 6 has been used as a base material for a bicycle wheel resin, glass fibers have been blended to impart strength and rigidity, and an elastomer component has been blended to impart impact resistance. Resin compositions are known.

However, the wheel using the polyamide 6-based resin composition is deformed or cracked when it is used in a high temperature atmosphere due to a decrease in strength and rigidity due to water absorption of polyamide 6. As a result, the environment area actually used is limited.

In general, since polyamide resins are water-absorbent, the strength and rigidity of the resins decrease as the water absorption increases,
The water absorption depends on the ambient temperature and humidity of the resin used. Therefore, a material that is less likely to deteriorate in strength and rigidity due to water absorption, that is, a polyamide resin having a lower water absorption than the polyamide 6, is desired as a bicycle wheel material. Polyamide 66 is a resin whose strength and rigidity are less deteriorated by water absorption than polyamide 6. However, if only the polyamide 66 component is used instead of the polyamide 6 component, the strength and rigidity are suppressed from being reduced, but the glass fiber rises (whitening phenomenon) on the surface of the resin molded product, the surface skin is roughened, and the appearance is deteriorated. It will be damaged.

Further, in the polyamide resin containing an aromatic ring as disclosed in Japanese Patent Application Laid-Open No. 4-149234, the strength and rigidity are lowered due to water absorption, and the glass fiber rises on the surface of the resin molded product (whitening phenomenon). ) Is suppressed, but since the crystallinity is low, the solidification time during molding becomes long.
In particular, due to the large size of bicycle wheel moldings, the molding cycle is more dependent on the cooling time in the mold of the molding rather than being dominated by the plasticizing time of the resin. Therefore, the resin having low crystallinity has a problem that the molding time cycle becomes long.

Japanese Unexamined Patent Publication (Kokai) No. 4-146962 discloses a bicycle wheel resin composition in which a polypropylene resin, a rubber and a glass resin are mixed with polyamide in order to improve the hygroscopic property. However, the resin composition has insufficient weld characteristics, and there is a problem in that the weld portion formed in the bicycle wheel portion may be broken.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a material satisfying all the properties required for the above-mentioned bicycle wheel material, that is, strength, rigidity, impact resistance, weld characteristics, and appearance under atmospheric equilibrium. Provided is a resin composition for a bicycle wheel, which has excellent properties and moldability.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that a polyamide resin having a specific composition, a specific elastomer component and a polyamide containing a specific amount of glass fiber are blended. The inventors have found that the above problems can be solved by forming a resin composition and controlling the crystallinity of the resin composition, and reached the present invention.

That is, the present invention relates to (A) polyamide 6, polyamide 66/6 copolymer, polyamide resin or polyamide 66/6 copolymer obtained by blending at least two kinds of polyamide resins selected from polyamide 66, and (B). Including olefin-based elastomer, (C) modified olefin-based elastomer, and (D) glass fiber,
Let (a), (B), (C), and (D) be the compounding amounts of a, b, c, d, (parts by weight), and a + b + c + d = 1.
When set to 00 parts by weight, 30 ≦ a ≦ 85, 0 ≦ b ≦ 2
0, 1 ≤ c ≤ 20, 15 ≤ d ≤ 60, and the crystallization temperature of the resin composition is 175
The gist of the invention is a resin composition for a bicycle wheel having a temperature of not less than 0 ° C and not more than 220 ° C.

The polyamide resin referred to in the present invention is at least 2 selected from polyamide 66 (hereinafter referred to as N66), polyamide 66/6 copolymer (hereinafter referred to as N66 / 6), and polyamide 6 (hereinafter referred to as N6). Polyamide resin blended with different types of polyamide resin or N66
N6, N66 / 6, N6 according to the present invention
Is a resin obtained by usual melt polymerization and solid phase polymerization using a salt of hexamethylenediamine and adipic acid, ε-caprolactam, α-aminocaproic acid, and a mixed raw material thereof as starting materials.

The blend ratio of N66, N66 / 6, N6 or the copolymer ratio of N66 / 6 of the present invention must be selected so that the crystallization temperature of the composition is 175 ° C. or higher and 220 ° C. or lower. . The crystallization temperature referred to here is D
SC resin composition under nitrogen atmosphere at 20 ℃ / min 300
Up to ℃, hold at 300 ℃ for 3 minutes, from there 20
It refers to the temperature of the crystallization peak when the temperature is lowered at ° C / min. It is preferably 180 ° C. or higher and 215 ° C. or lower. 1
If the temperature is lower than 75 ° C., the crystallization becomes slow, so that the solidification of the resin in the mold becomes slow, bubbles easily occur in the thick portion, and the time cycle at the time of molding becomes long. If the temperature is higher than 220 ° C., the crystallization will be too fast, and the glass fibers will float on the surface of the molded product, resulting in poor appearance.

In the case of blended polymer, the preferred polyamide component is a blend of N66, N66 / 6 and N6, and the N66 component may be contained in an amount of 30% by weight or more and 90% by weight or less. Preferred N66 / 6 copolymer
The ratio is a copolymer containing 80% by weight or more and 95% by weight or less as N66 component.

In the present invention, the polyamide resin is added in an amount of 30 to 85 parts by weight, preferably 35 to 80 parts by weight, per 100 parts by weight of the resin composition. If it is less than 30 parts by weight, sufficient impact strength cannot be obtained, and if it is more than 85 parts by weight, sufficient strength and rigidity cannot be obtained.

The glass fiber used in the present invention is a glass fiber having an average diameter of 5 to 20 μm, which is used in ordinary glass fiber reinforced polyamide resin without any particular designation, and the glass fiber surface is treated with a silane binder. is there. The glass fiber content is 15 to 6 per 100 parts by weight of the resin composition.
It is 0 part by weight, preferably 20 to 50 parts by weight. If it is less than 15 parts by weight, sufficient strength and rigidity cannot be obtained, and
If the amount is more than 60 parts by weight, the glass fibers are likely to be lifted on the surface of the molded product, and it becomes difficult to obtain a product having good appearance.

The olefin elastomer referred to in the present invention is a hydrogenated product of a copolymer of ethylene and propylene (hereinafter referred to as EP rapa), a block copolymer of butadiene and styrene, a block copolymer of butadiene and styrene (hereinafter referred to as HTR rubber). -Referred to as) and the like. Of these, EP lovers and HTR lovers are particularly preferable.

The modified olefin elastomer referred to in the present invention is a polymer in which an anhydride of dicarboxylic acid is added to the above olefin elastomer. Olefin-based elastomers to which maleic anhydride is added are preferable, those obtained by adding maleic anhydride to EP rubber (hereinafter referred to as MEP rubber), those obtained by adding maleic anhydride to HTR rubber (hereinafter referred to as "maleic anhydride") MHTR rubber)
Is good.

The blending amount of the olefin elastomer and the modified olefin elastomer is the polyamide resin composition 1
0 to 20 parts by weight of olefin-based elastomer relative to 00 parts by weight
The modified olefin elastomer is 1 to 2 parts by weight.
0 parts by weight. The total amount of the olefin elastomer and the modified olefin elastomer is 20 parts by weight or less, preferably 15 parts by weight or less. If the amount is more than 20 parts by weight, sufficient strength and rigidity cannot be obtained. In order to impart sufficient impact resistance, it is necessary to add at least 5 parts by weight of the modified olefin elastomer or the olefin elastomer and the modified olefin elastomer. The mixing ratio of the olefin-based elastomer and the modified olefin-based elastomer is not particularly limited, but it is better to add at least 5% by weight of the modified olefin-based elastomer when adding the olefin-based elastomer. Weld strength cannot be obtained.

It is necessary that the blending ratio of them be such that the crystallization temperature of the composition is 175 ° C. or higher and 220 ° C. or lower. It is preferably 180 ° C. or higher and 215 ° C. or lower.

The composition of the present invention may contain various additives such as antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, lubricants, colorants, etc., which are added to ordinary thermoplastic resins as required. You may.

The composition of the present invention can be prepared by melt-kneading the above-mentioned blending components by a method usually used. As the kneading machine, an extruder, a Banbury mixer, a super mixer, etc. are used. Among them, the extruder is used, and the melt kneading is carried out at a resin temperature of 220 to 320 ° C. Is preferred.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

The characteristics of the resin compositions described in Examples and Comparative Examples were evaluated by the following methods. (1) Hygroscopic property: Tensile strength is used as a substitute, ASTM-D63
The test piece used for evaluation in accordance with 8 is AST
The M-D638Type1 test piece was immersed in 80 ° C water for 8 hours, and then left in a thermostatic chamber at 23 ° C and 50% humidity for 30 days,
I adjusted my condition. (2) Rigidity property: Substituting flexural modulus, ASTM-D7
It carried out according to 90. (3) Izod impact strength: Carried out according to ASTM-D256 (with V notch). (4) Appearance: Evaluation is 130 mm × 130 mm × thickness 3
mm flat plate molded product was molded under the conditions of Toshiba IS150E injection molding machine, cylinder temperature 290 ° C., mold temperature 90 ° C., injection / cooling cycle 10/20 seconds, and the surface of the resulting molded product was measured according to JIS-K7105. The glossiness was measured. (5) Weld characteristics: Tensile strength at the weld portion was used as a substitute, and the weld characteristics were measured according to ASTM-D638. As the test piece used for evaluation, a molded article having a weld portion at the center of the ASTM-D638 Type 1 test piece was used.

Example 1 38 parts by weight of N6 (polymer of 98% sulfuric acid solution viscosity 2.4), 24.5 parts by weight of N66 (Leona 1200 manufactured by Asahi Kasei Co., Ltd.), EP rubber
(Mitsui Petrochemical Co., Ltd. product name, Tuffma-PO180) 3 parts by weight, MEP lover (Exxon Co. product name, Exzero-
VA1803) 0.5 parts by weight, HTR rubber (trade name of Asahi Kasei Corp., Tabtec H1052) 2 parts by weight, MHTR
Lavers (Product name of Asahi Kasei, Tuftec M1953) 2
By weight, 30 parts by weight and 30 parts by weight of glass fiber (trade name: 03JA416, manufactured by Asahi Fiber Glass Co., Ltd.) were kneaded together by a twin-screw extruder to obtain a pellet-shaped sample.

For the sample, according to the evaluation method described above,
The evaluation was performed according to the criteria of Table 1, and the results are shown in Table 2.

(Examples 2 to 6 and Comparative Examples 1 to 3) Table 2
The formulation and evaluation were made in the same manner as in Example 1, and the results are shown in Table 2.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Effect] It was possible to provide a bicycle wheel resin composition which is excellent in strength, rigidity, impact resistance, weld characteristics, appearance properties and moldability under atmospheric equilibrium required for bicycle wheel materials.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 53/02 LLY LLZ

Claims (1)

[Claims] 1. (A) Polyamide 6, polyamide 66 /
6 copolymers, polyamide resin made by blending at least two polyamide resins selected from polyamide 66 or polyamide 66/6 copolymer (B) Olefin-based elastomer (C) Modified olefin-based elastomer (D) Glass fiber And the compounding amounts of (A), (B), (C), and (D) are a, b, c, and d (parts by weight), respectively, and a + b + c +
When d = 100 parts by weight, 30 parts by weight ≦ a ≦ 85 parts by weight, 0 parts by weight ≦ b ≦ 20 parts by weight, 1 part by weight ≦ c ≦ 20
Parts by weight, 15 parts by weight ≦ d ≦ 60 parts by weight, and the crystallization temperature of the resin composition is 175 ° C.
A resin composition for a bicycle wheel having a temperature of 220 ° C. or higher.