JP2005060539A - Polyamide resin composition and composite molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively produce a composite molded product manifesting excellent thermobonding properties and good moldability by combining entirely different kinds of a hard material and a flexible material of a polyamide-based resin and a polyester-based thermoplastic elastomer. <P>SOLUTION: The composite molded product is obtained by thermobonding (F) the polyester-based thermoplastic elastomer to a molded product comprising a polyamide-based resin composition obtained by adding (E) 0-200 pts. wt. inorganic filler to 100 pts. wt. polyamide-based resin composition comprising (A) 20-70 wt.% crystalline polyamide resin, (B) 5-30 wt.% semiaromatic amorphous polyamide resin, (C) 15-45 wt.% styrenic copolymer and (D) 2-15 wt.% modified hydrogenated styrenic copolymer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, the surface of a molded article having excellent strength, rigidity and impact resistance of a polyamide resin is coated with a flexible and heat-resistant polyester thermoplastic elastomer and heat-sealed, whereby the strength, rigidity and vibration absorption are In addition, the present invention relates to a composite molded body made of a polyamide-based resin and a polyester-based thermoplastic elastomer having both grip properties, packing, and sealing properties.

Conventionally, composite molded bodies made of hard and soft materials have been compositely molded with a combination of hard olefin materials and homogeneous materials such as olefin-based soft materials, thermally bonded, and various product developments have been carried out. (For example, Journal of Japan Rubber Association, Vol. 69, No. 9, P-631 (1996), and Plastics, Vol. 4, No. 3, P-30 (1997), etc.) To thermally bond different materials For this, compatibility between different materials is extremely important, and in the case of homogeneous materials, heat bonding is relatively easy. However, such a combination of homogeneous materials has a drawback that only a very limited material can be used and the field of application is limited.
Journal of Japan Rubber Association, Vol. 69, no. 9, P.I. 631 (1996) Plastics, Vol. 4, no. 3, P.I. 30 (1997)

On the other hand, a general-purpose elastomer such as styrene-based thermoplastic elastomer or olefin-based thermoplastic elastomer is blended with a polyamide-based thermoplastic elastomer made of polyether block amide or an engineering elastomer having a polar group, such as a polyester thermoplastic elastomer, to make it flexible. It has been reported that materials are made and thermally bonded to hard materials such as ABS, polycarbonate, nylon and PBT. (For example, Japanese Patent Publication No. 6-9878, Japanese Patent Publication No. 7-11662 and the like) However, these blended methods have insufficient thermal adhesive strength with a combination of different polar groups such as polyamide resin and polyester resin. This is not preferable because the composite molded article peels off.
Japanese Patent Publication No. 6-9878 Japanese Patent Publication No.7-11662

  The present invention has been made in order to solve the problems of the prior art. The combination of a hard material and a flexible material, which are completely different types of polyamide-based resin and polyester-based thermoplastic elastomer, has excellent thermal adhesiveness and moldability. An object of the present invention is to produce a good composite molded article at a low cost.

  As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention comprises (A) 20 to 70% by weight of crystalline polyamide resin, (B) 5 to 30% by weight of semi-aromatic amorphous polyamide resin, (C) 15 to 45% by weight of styrene copolymer, and (D) A polyamide resin composition comprising (E) 0 to 200 parts by weight of an inorganic filler with respect to 100 parts by weight of a polyamide resin composition comprising 2 to 15% by weight of a modified hydrogenated styrene copolymer. It is. In a preferred embodiment, the styrene copolymer is a styrene copolymer containing a styrene component and an acrylonitrile component, and (D) the modified hydrogenated styrene copolymer has a functional group that reacts with a polyamide resin. It is a hydrogenated styrene copolymer. In addition, the present invention is a composite molded body characterized in that (F) a polyester-based thermoplastic elastomer is thermally bonded to a molded body made of the polyamide-based resin composition.

  The composite molded body comprising the polyamide resin composition of the present invention is excellent in the thermal adhesiveness between the polyamide resin composition and the polyester thermoplastic elastomer, and therefore has excellent strength, rigidity, impact resistance and excellent vibration. It has surface characteristics such as absorption, packing seal and grip. Therefore, it can be used in a wide range of application fields such as electric tools, fishing gear, sports equipment, recreational equipment, automobile parts such as shift lever housings, office supplies, etc., and contributes greatly to the industry.

Embodiments of the present invention will be described below.
The (A) crystalline polyamide resin used in the present invention is a polyamide resin that is at least partially crystalline, has an amide bond (—CONH—) in the molecule, and has a melting point (according to JIS K 7121). Specifically, nylon 6, nylon 66, nylon 6 / nylon 66 copolymer, nylon 46, nylon 12, nylon 11, nylon 6T / nylon 66 co-weight In the present invention, nylon 6 and nylon 66 are particularly preferable from the viewpoints of rigidity, durability, heat resistance, economy and the like, but are not limited thereto.
The number average molecular weight of the (A) crystalline polyamide resin used in the present invention is preferably 7,000 to 30,000. In the case of 7,000 or less, the strength may be insufficient, and in the case of 30,000 or more, the melt moldability deteriorates, which is not preferable.

  The blending amount of the (A) crystalline polyamide resin used in the present invention is 20 to 75% by weight with respect to the total resin components. Particularly preferred is 45 to 70% by weight. If it is less than 20% by weight, the advantages such as high rigidity, heat resistance and chemical resistance of the crystalline polyamide are impaired. When it is more than 75% by weight, the thermal adhesiveness with the polyester-based thermoplastic elastomer is deteriorated when it is made into a composite.

  The (B) semi-aromatic amorphous polyamide resin used in the present invention has an amide bond (—CONH—) in the molecule and has a melting point (melting peak temperature determined in accordance with JIS K 7121). The glass transition point only exists, and those having a number average molecular weight of 7,000 to 30,000 are preferably used. Specific examples include nylon 6T / nylon 66 copolymer, nylon 6T / nylon 6I copolymer, nylon TMD-T / nylon 6 copolymer, etc. In the present invention, nylon 6T / nylon 6I copolymer. Etc., and blends with various nylon copolymers are more preferred.

  The blending amount of the (B) semi-aromatic amorphous polyamide resin used in the present invention is 5 to 20% by weight based on the total resin components. Preferably it is 5 to 15% by weight. If the blending amount is 20% by weight or more, the effect of improving the adhesiveness is small, and the heat-resistant mechanical properties when used at a high temperature are deteriorated. When the blending amount is 5% by weight or less, the effect of improving the thermal adhesiveness is low.

  The (C) styrene copolymer of the present invention is a copolymer containing a styrene component and an acrylonitrile component. Specifically, ABS resin (acrylonitrile / butadiene / styrene copolymer), AS resin (acrylonitrile / styrene copolymer), AES resin (terpolymer of acrylonitrile / EPDM / styrene), ASA resin (acrylonitrile / Styrene / acrylic acid ester terpolymer) and the like are preferable, and ABS resin is particularly preferable. The blending amount of the styrenic copolymer is 15% by weight to 45% by weight. Preferably it is 15 weight%-40 weight%. When the blending amount is 15% by weight or less, the adhesive strength between the polyamide-based molded body and the polyester-based thermoplastic elastomer cannot be sufficiently obtained. On the other hand, if the blending amount is 45% by weight or more, the effect of improving the adhesive strength is small and the physical properties are lowered, which is not preferable.

  The (D) modified hydrogenated styrene copolymer of the present invention is SEBS (styrene / ethylene / butylene / styrene block copolymer) which is a hydrogenated product of SBS (styrene / butadiene / styrene block copolymer). , SIS (hydrogenated product of styrene / isoprene / styrene block copolymer, SEPS (styrene / ethylene propylene / styrene block copolymer), and HSBR (hydrogenated product of SBR (styrene / butadiene copolymer)) Styrene / ethylene / butylene copolymer) is preferable, but SEBS is preferable.These hydrogenated styrene copolymers react with the polyamide resin in order to improve the compatibility with the polyamide resin. A modified hydrogenated styrene copolymer having a functional group is preferable.What is a functional group that reacts with a polyamide resin? Specific examples include a carboxylic acid group, an acid anhydride group, an epoxy group, an amino group, an isocyanate group, and an oxadrine group. Among these, an acid anhydride group has the highest reactivity and is particularly preferable. The hydrogenated styrene copolymer can be produced by mixing the hydrogenated styrene copolymer with a compound having a functional group such as an acid anhydride and an organic peroxide, and kneading the mixture with an extruder or the like. However, the manufacturing method is not limited in the present invention.

  The blending amount of the modified hydrogenated styrene copolymer is 2% by weight to 15% by weight. Preferably they are 2 weight%-13 weight%. When the blending amount is 2% by weight or less, (C) a styrene copolymer, (A) a crystalline polyamide resin, and (B) a semi-aromatic amorphous polyamide resin have poor compatibility and a stable polyamide resin composition is obtained. If it is 15% by weight or more, the effect of improving the adhesive strength is small, and the physical properties are greatly deteriorated.

  Specific examples of the inorganic filler (E) of the present invention include glass fibers, carbon fibers, ceramic fibers, various whiskers, fibrous inorganic reinforcing materials such as acicular wollastonite, silica, alumina, talc, kaolin, quartz, Examples thereof include powdery inorganic fillers such as powdered glass, mica, and graphite. These inorganic fillers can be used alone or in combination of two or more. These inorganic fillers may be treated with a silane coupling agent as a surface treatment agent, and aminosilane treatment is particularly preferred.

  The blending amount of the (E) inorganic filler is (A) crystalline polyamide resin, (B) semi-aromatic amorphous polyamide resin, (C) styrene copolymer and (D) modified hydrogenated styrene. It is 0-200 weight part with respect to 100 weight part of polyamide-type resin compositions which consist of a system copolymer. Preferably it is 0-160 weight part, Most preferably, it is 0-150 weight part. When the inorganic filler exceeds 200 parts by weight, glossy spots on the appearance of the molded product occur, resulting in poor appearance.

  The polyamide resin composition of the present invention includes carbon black, copper oxide and / or alkali metal halide compounds, which are weather resistance improvers used in ordinary polyamide resin compositions, and phenolic antioxidants as light or heat stabilizers. And phosphorus-based antioxidants, pigments, dyes, antistatic agents, flame retardants, lubricants, and the like can also be added and blended.

  The (F) polyester-based thermoplastic elastomer used in the present invention is a resin with excellent elastic recovery composed of a hard component and a soft component. Specifically, polybutylene terephthalate, polynaphthalene terephthalate as a hard component, and a soft component as a hard component. Can include polyester-based thermoplastic elastomers composed of polytetramethylene glycol or ε-caprolactone. The surface hardness of the polyester thermoplastic elastomer is 98 to 40 degrees, more preferably 96 to 45 degrees in terms of JIS-A hardness. If the hardness exceeds 98 degrees, vibration absorption, grip and sealing properties are inferior, and if it is 45 degrees or less, heat resistance and moldability are inferior and it is difficult to coat and form a polyamide-based molded article.

In the molded product made of the polyamide resin composition of the present invention and the composite molded product made of (F) a polyester-based thermoplastic elastomer, the thermal bond strength between them is extremely important. A polyamide resin composition comprising (A), (B), (C), (D) and (E) of the present invention using a 1A type tensile test dumbbell mold conforming to ISO527-1 and 2 After forming a dumbbell molded product for tensile testing using, cut from the center of the tensile dumbbell molded product, and attach only one half of the molded product to the mold's cure (F) Add polyester thermoplastic elastomer A sample for thermal adhesion evaluation can be obtained by molding by an insert molding method. This tensile dumbbell test piece has a joint surface between the polyamide-based resin composition and the polyester-based thermoplastic elastomer at the center. (See FIG. 1) The thermal bond strength between the molded article comprising the polyamide resin composition of the present invention and the polyester-based thermoplastic elastomer is 3 kgf / 40 mm ² or more when subjected to a tensile test evaluation with this tensile dumbbell test piece for thermal adhesion evaluation. It is preferable that More preferably, it is 4 kgf / 40 mm ² or more. If the thermal bond strength is less than 3 kgf / 40 mm ² , a durable composite molded body cannot be obtained. The thermal adhesive strength of a general molded polyamide resin and a polyester thermoplastic elastomer evaluated by the same method is 0 to 0.05 kgf / 40 mm ^2. A composite molded body having excellent durability and excellent durability can be obtained.

  The production method of the composite molded product in the present invention is not particularly limited, and includes all known production methods in which a polyester thermoplastic elastomer is coated or laminated on a molded product composed of a polyamide-based resin composition and heat-sealed. It is. For example, after a polyamide-based resin composition is injection-molded, immediately after the mold is rotated, a polyester-based thermoplastic elastomer is further injection-molded on the entire surface or a part of the surface of the polyamide-based molded body. “Two-color injection molding method” in which coating and heat-sealing are performed, a molded product in which a polyamide-based resin composition is injection-molded in advance is mounted in a cavity of a mold, and a polyester-based thermoplastic elastomer is applied to the entire surface or a part of the molded product. “Outsert or insert molding method” for additional molding, “Double-layer extrusion method” in which a polyamide-based resin composition and a polyester-based thermoplastic elastomer are simultaneously extruded and heat-sealed by a two-layer extrusion molding machine, extrusion molding or injection in advance On the surface of the molded polyamide-based molded article, this is also made of a polyester-based thermoplastic elastomer that has been extruded or injection-molded in advance. The "thermal ramie method", in which a sheet or a molded product is laminated and fused with an ultrasonic welding machine or a vibration welding machine, can be employed, but the present invention is not limited to these manufacturing methods. Absent.

  By using the polyamide-based resin composition of the present invention, a composite molded body having high strength and high rigidity and high thermal adhesive strength with a polyester-based thermoplastic elastomer can be heated without using a special adhesive or the like. It can be obtained by bonding. As a result, a composite molded body having high durability, functionality and design can be produced.

The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples.
(Evaluation methods)
1. Melting point The sample was subjected to DSC measurement under the following conditions, and the melting point (melting peak temperature Tpm) was determined according to JIS K7121.
(DSC measurement conditions)
Device name: DSC3100 manufactured by MacScience
Pan ： Aluminum pan (non-airtight)
Sample weight; 4mg
Temperature rising start temperature: 30 ° C
Temperature rising rate: 20 ° C./min.
Atmosphere: Argon

2. Tensile strength, tensile elongation, flexural strength, flexural modulus Evaluation of strength physical properties was performed using a tensile test piece and a bending test piece in accordance with ISO 178 and ISO 527-1, -2 at a cylinder temperature of 250 ° C and a mold temperature of 80 ° C. The tensile strength test was based on ISO 527-1 and -2, and the bending test was based on ISO 178.

3. Thermal Bonding Strength of Insert Molded Products Evaluation of thermal bonding strength between a molded article made of a polyamide resin composition and a polyester thermoplastic elastomer is a 1A type tensile test based on ISO527-1, 2, as shown in FIG. A piece was produced by the insert molding method in which a polyester thermoplastic elastomer was additionally molded as described above, and the thermal bond strength was measured by a tensile test. The polyester thermoplastic elastomer was additionally molded at a cylinder temperature of 250 ° C. and a mold temperature of 60 ° C. There is an adhesion surface at the center of the tensile test piece, and the adhesion area is 4 mm thickness × 10 mm width = 40 mm ² . The tensile speed at the time of strength measurement was measured at 50 mm / min.

(Materials used)
Production of various raw materials and modified products used in Examples and Comparative Examples is as follows.
(A) Nylon 6 (Toyobo Co., Ltd., Toyobo nylon T-840, melting point: 222 ° C.) was used as the crystalline polyamide resin.
(B) Nylon 6T / 6I copolymer (Mus Japan Co., Ltd., Grivory G21, no melting peak) was used as a semi-aromatic amorphous polyamide resin.
(C) ABS resin (Toyolac 450Y, manufactured by Toray Industries, Inc.) and ASA resin (Lulan S, manufactured by BASF Japan) were used as the styrene copolymer. Maleic acid-modified SEBS (Tuftec M1943, manufactured by Asahi Kasei Co., Ltd.) (also referred to as MAH-g-SEBS) was used as the modified styrene copolymer.
(D) As the inorganic filler, glass fiber (TP57E, manufactured by Nippon Sheet Glass Co., Ltd.) was used.
In addition, Irganox B1171 (manufactured by Ciba Geigy) was used as a heat stabilizer.
(E) Perprene P-55B (manufactured by Toyobo Co., Ltd., hard component PBT, soft component PTMG, hardness 94A) was used as the polyester thermoplastic elastomer to be thermally bonded to the polyamide resin molded body.

(Production of polyamide resin composition)
The resin components are mixed from the components listed in Table 1 in the proportions shown in the table, and charged into a 40 mmφ twin-screw extruder set at a cylinder temperature of 240 to 270 ° C., and side feed is performed so that the glass fibers are in the proportions in the table. Were added to the molten resin, kneaded and extruded, cast into water, and cut to obtain pellets. The target resin composition was obtained by surface-attaching a heat stabilizer and a release agent at a ratio shown in the table with respect to 100 parts by weight of the pellets.

(Examples 1 to 3, Comparative Examples 1 and 2)
The evaluation results of Examples and Comparative Examples are shown in Table 1.
As is clear from Examples 1 to 3, the polyamide resin composition of the present invention has an adhesive surface of the system-coated molded body that has excellent heat-fusibility, is firmly bonded, and provides a durable polyamide-based coated molded body. You can see that On the other hand, Comparative Example 1 has a composition that does not contain a semi-aromatic amorphous polyamide resin, and Comparative Example 2 has a composition that does not contain a modified hydrogenated styrene copolymer, but Comparative Example 1 exhibits good physical properties. However, adhesion is low. In Comparative Example 2, good physical properties are not expressed and adhesiveness is low. In Comparative Example 1, almost no thermal fusion is observed between the polyamide-based molded article and the polyester-based thermoplastic elastomer, and an evaluation sample is taken out from the mold. At that time, the polyamide-based molded product and the polyester-based thermoplastic elastomer are not bonded.

  The composite molded body comprising the polyamide resin composition of the present invention is excellent in the thermal adhesiveness between the polyamide resin composition and the polyester thermoplastic elastomer, and therefore has excellent strength, rigidity, impact resistance and excellent vibration. It has surface characteristics such as absorption, packing seal and grip. Therefore, it can be used in a wide range of application fields such as electric tools, fishing gear, sports equipment, recreational equipment, automobile parts such as shift lever housings, office supplies, etc., and contributes greatly to the industry.

Test piece for thermal bond strength measurement

Explanation of symbols

1: Part molded with a polyamide-based resin composition 2: Part molded with a polyester-based thermoplastic elastomer
(Additional molding part)
3: Thermal bonding part of both

Claims (5)

  (A) 20 to 70% by weight of crystalline polyamide resin, (B) 5 to 30% by weight of semi-aromatic amorphous polyamide resin, (C) 15 to 45% by weight of styrene copolymer, and (D) modified. A polyamide resin composition comprising 0 to 200 parts by weight of (E) inorganic filler with respect to 100 parts by weight of a polyamide resin composition comprising 2 to 15% by weight of a hydrogenated styrene copolymer.   (C) The polyamide resin composition according to claim 1, wherein the styrene copolymer is a styrene copolymer containing a styrene component and an acrylonitrile component.   (D) The polyamide resin composition according to claim 1 or 2, wherein the modified hydrogenated styrene copolymer is a hydrogenated styrene copolymer having a functional group that reacts with the polyamide resin. (F) The polyamide resin composition according to any one of claims 1 to 3, which has a thermal adhesive strength with a polyester-based thermoplastic elastomer of 3 kgf / 40 mm ² or more.   A composite molded article, wherein (F) a polyester thermoplastic elastomer is thermally bonded to a molded article comprising the polyamide resin composition according to any one of claims 1 to 4.

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