JP2010111841A - Polyamide resin composition and molding comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material exhibiting the suppression of physical property degradation due to water absorption and good appearance, while keeping high rigidity and impact characteristics inherent to polyamide resins. <P>SOLUTION: The polyamide resin composition comprises (A) 55-90 wt.% polyamide having 100-200 ml/g viscosity number prepared according to ISO 307 (96% sulfuric acid method), (B) 9-44 wt.% natural polypropylene having 1-60 g/10 min melt flow rate measured according to ISO 1133 (230°C, 5 min residence time and 2,160 g load) and (C) 1-10 wt.% modified polyolefine having 20-80 g/10 min melt flow rate measured according to ISO 1133 (230°C, 5 min residence time and 2,160 g load) and having -20 to 0°C glass transition point measured according to JIS K7196 (5°C/min temperature increasing rate). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention maintains mechanical properties such as mechanical strength, rigidity and wear resistance of polyamide resin and good surface appearance, and can suppress water absorption, which is a defect of polyamide resin. The present invention relates to a polyamide resin composition characterized by a small change.

  Conventionally, polyamide resins have excellent mechanical properties such as rigidity, impact resistance, and wear resistance, as well as good heat resistance and molding processability, so they are used in various applications such as automotive parts, electrical parts, and general machine parts. ing. However, the polyamide resin is characterized by a decrease in rigidity and a large dimensional change due to water absorption. Moreover, there also exists a fault of generating a crack under contact with a specific inorganic metal salt.

  Attempts to add polypropylene to the polyamide resin for the purpose of improving the characteristics and defects caused by water absorption of the polyamide resin as described above were carried out as described in Patent Document 1, Patent Document 2 and Patent Document 3. Examples are also in the past.

However, all of the polyamide resin compositions produced using the above-mentioned known techniques have an effect for reducing water absorption, but the compatibility between polyamide and polypropylene is not sufficient, so that the rigidity during absolutely dryness is low, and There are problems such as poor surface appearance of the molded product, and it is still unsatisfactory from the practical application technology. Therefore, there is still a polyamide resin composition having high impact resistance and good molded product surface appearance while retaining the excellent rigidity, wear resistance, and heat resistance inherent in polyamide, and having small physical property deterioration and dimensional change due to water absorption. The current situation is that it has not been obtained.
Japanese Patent Laid-Open No. 01-103662 JP 09-157454 A Japanese Patent Laid-Open No. 13-202935

  The present invention retains the inherent rigidity, wear resistance, and heat resistance of the polyamide resin, has a small deterioration in physical properties and changes in dimensions due to water absorption, and has a high impact resistance and a good molded product surface appearance. It is an object of the present invention to provide a characteristic polyamide resin composition.

  As a result of intensive studies to solve the above problems, the present inventor adopts the following means.

The present invention is as follows.
1. (A), (B), and (C) as a total of 100% by weight, (A) 55-90% by weight polyamide, (B) 9-45% by weight unmodified polypropylene, (C) 1-10% by weight modified polyolefin %, The viscosity number obtained according to ISO 307 (96% sulfuric acid method) of polyamide (A) is 100 to 200 ml / g, and (B) ISO 1133 of unmodified polypropylene ( Melt flow rate measured in accordance with ISO 1133 of a modified polyolefin (temperature 230 ° C., residence time 5 min, load 2160 g) measured at 230 ° C., residence time 5 min, load 2160 g) Measured in accordance with JIS K7196 (heating rate 5 ° C./min). A polyamide resin composition having a lath transition point of -20 to 0 ° C.
2. 2. The polyamide resin composition according to 1, comprising 100 parts by weight of the total of (A), (B), and (C), and 10 to 150 parts by weight of an inorganic filler.
3. 3. The polyamide resin composition according to 1 or 2, wherein the polyamide (A) is (A1) polyamide 66 or (A2) polyamide 6.
4.1 A molded body made of the polyamide according to any one of 1 to 3.

  According to the present invention, while maintaining the inherent rigidity, wear resistance, and heat resistance of the polyamide resin, there is little decrease in physical properties and dimensional change due to water absorption, which is a drawback of the polyamide resin, and high impact resistance and good performance. A polyamide resin composition characterized by having a molded product surface appearance can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  The polyamide (A) constituting the polyamide resin composition in the present invention is a polyamide mainly composed of amino acids, lactams, or diamines and dicarboxylic acids. Specific examples include lactams such as ε-caprolactam, enantolactam, and ω-laurolactam, amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid, tetramethylenediamine, hexamethylenediamine, and undeca. Methylenediamine, dodecamethylenediamine 1.2.2.4- / 2.4.4-1 limethylhexamethylenediamine, 5 = methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1.3 -Diamines such as bisaminomethylcyclohexane, 1.4-bisaminomethylcyclohexane, bis-p-aminocyclohexylmethane, bis-p-aminocyclohexylpropane, isophoronediamine, adipic acid, speric acid, azelaic acid, sepacic acid , Dodecanoic acid 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, dicarboxylic acids such as dimer acid. These components are used for polymerization alone or in the form of a mixture of two or more, and the polyamide homopolymer and copolymer thus obtained can be used in the present invention. Particularly useful polyamides in the present invention are polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612). Polyhexamethylene terephthalamide (nylon 6T), polyhexamethylene isophthalamide (nylon 6I), polyundecanamide (nylon 11), polydodecanamide (nylon 12), and copolymers and mixtures of these polyamides. Nylon 6 and nylon 66 are preferable in terms of appearance, strength, rigidity, and toughness.

  The polyamide (A) used in the present invention is required to have a viscosity number of 100 to 200 ml / g, preferably 100 to 160 ml / g, determined by a measurement method based on ISO 307. (A) When the viscosity number of the polyamide is less than 100 ml / g, the rigidity and impact characteristics are lowered. Conversely, when it exceeds 200 ml / g, the fluidity at the time of melt molding is lowered and the moldability is deteriorated. The blending amount of (A) polyamide is 55 to 90% by weight, preferably 55 to 75% by weight, where the total of (A) polyamide, (B) unmodified polypropylene, and (C) modified polyolefin is 100% by weight. is there. (A) If the blending amount of the polyamide is less than 55% by weight, the inherent rigidity of the polyamide cannot be maintained. Conversely, if the blending amount exceeds 90% by weight, the strength and rigidity during water absorption decrease and the dimensional change is large. Become.

  The unmodified polypropylene (B) used in the present invention requires a melt flow rate (MFR) defined by ISO 1133 (temperature 230 ° C., residence time 5 min, load 2160 g) of 1 to 60 g / 10 min, preferably 5 -50 g / 10 min. (B) When the MFR of unmodified polypropylene is less than 1 g / 10 min, the fluidity at the time of melt molding is lowered and the moldability is deteriorated. Conversely, if the MFR of (B) unmodified polypropylene exceeds 60 g / 10 min, the original properties of polyamide cannot be obtained. The blending amount of (B) unmodified polypropylene is 9 to 44% by weight, preferably 15 to 35, where the total of (A) polyamide, (B) unmodified polypropylene, and (C) modified polyolefin is 100% by weight. % By weight. If the blending amount of (B) unmodified polypropylene is less than 9% by weight, the effect of reducing water absorption is insufficient. Conversely, if the blending amount of (B) unmodified polypropylene exceeds 40% by weight, the rigidity is lowered. Is big.

  The (C) modified polyolefin used in the present invention requires an MFR defined by ISO 1133 (temperature 230 ° C., residence time 5 min, load 2160 g) of 20 to 80 g / 10 min, preferably 40 to 60 g / 10 min. . (C) If the MFR of the modified polyolefin is less than 20 g / 10 min, the original properties of the polyamide cannot be obtained. Conversely, if the MFR exceeds 80 g / 10 min, the rigidity and impact properties cannot be satisfied. (C) The modified polyolefin needs to have a glass transition point of -20 to 0 ° C measured according to JIS K7196 (temperature increase rate 5 ° C / min). (C) If the glass transition point of the modified polyolefin is less than −20 ° C., the rigidity cannot be maintained in a high temperature environment. Conversely, if the glass transition point exceeds 0 ° C., the crystallization is insufficient and the rigidity is insufficient. Can not be satisfied. The blending amount of the (C) modified polyolefin is 1 to 10% by weight, preferably 3 to 10%, with the total of (A) polyamide, (B) unmodified polypropylene and (C) modified polyolefin as 100% by weight. % By weight. If the blending amount of the (C) modified polyolefin is less than 1 part by weight, the compatibility between the (A) polyamide and the (B) modified polypropylene is insufficient, and good rigidity, impact characteristics, and surface appearance cannot be obtained. When it exceeds 10% by weight, strength and rigidity are lowered.

  In the present invention, an inorganic filler can be further blended. Any inorganic filler can be used without particular limitation as long as it is generally used for reinforcing a resin. Examples of the inorganic filler include a plate shape, a rod shape, and a spherical shape. Such inorganic fillers include, for example, fibrous reinforcing materials such as glass fibers, carbon fibers, and aramid fibers, glass beads, glass flakes, talc, wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, Asbestos, aluminosilicate, calcium silicate, alumina, silica, diatomaceous earth, zinc oxide, calcium oxide, magnesium oxide, tin oxide, antimony oxide, zirconium oxide, titanium oxide, iron oxide and other metal oxides, calcium carbonate, magnesium carbonate, carbonic acid Zinc, barium carbonate, dolomite, hydrotalcite, calcium sulfate, barium sulfate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, basic magnesium carbonate, ceramic beads, boron nitride, aluminum nitride, silicon carbide, etc. And the like. These may be hollow, and it is also possible to use two or more of these inorganic fillers. These inorganic fillers may be used after being treated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound. The fibrous reinforcing material can be selected from long fiber type or short fiber type chopped strands, milled fibers, or the like.

  In particular, glass fiber, glass bead, talc, mica, wollastonite, and kaolin are preferable in terms of rigidity, surface appearance, and dimensional stability. In the case of glass fibers, the number average fiber length is preferably 200 μm or more in terms of strength and rigidity. In the case of glass beads, talc, mica, wollastonite, and kaolin, the average particle size is preferably 0.5 to 10 μm. If the average particle size is less than 0.5 μm, aggregation tends to occur and the rigidity may be poor. On the other hand, if the average particle size exceeds 10 μm, the rigidity and surface appearance may be inferior. The average particle diameter can be obtained as a 50% integrated value of the particle diameter measured by the laser diffraction method.

  Moreover, as a compounding quantity of an inorganic filler, 10-150 weight part is preferable for the total amount of (A)-(C) component as 100 weight part. By blending 10 parts by weight or more, the strength and rigidity of the polyamide resin composition can be improved, and by blending 150 parts by weight or less, the fluidity and appearance of the polyamide resin composition can be easily manipulated. Therefore, it is preferable.

  In the polyamide resin composition of the present invention, other components within the range not impairing the effects of the present invention, such as antioxidants and heat stabilizers (hindered phenols, hydroquinones, phosphites, and substituted products thereof), Weathering agents (resorcinol, salicylate, benzotriazole, benzophenone, hindered amine, etc.), mold release agents and lubricants (montanic acid and its metal salts, esters, half esters, stearyl alcohol, stearamide, various bisamides, bisamides Urea and polyethylene wax), crystal nucleating agent (talc, silica, kaolin, clay, etc.), plasticizer (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agent (alkyl sulfate type anionic charging) Inhibitor, polyoxyethylene sol Nonionic antistatic agents such as tan monostearate, betaine amphoteric antistatic agents, etc.), flame retardants (eg, red phosphorus, melamine cyanurate, magnesium hydroxide, aluminum hydroxide and other hydroxides, polyphosphoric acid) Ammonium, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resin or a combination of these brominated flame retardants and antimony trioxide), and other polymers can be added.

  The method for obtaining the polyamide resin composition of the present invention is not particularly limited. In melt kneading, for example, when melt kneading with a twin screw extruder, (A) polyamide, (B) unmodified polypropylene, and (C) modified Blending polyolefin and inorganic filler in advance using a blender and feeding from the main feeder, blending (A) polyamide, (B) unmodified polypropylene and (C) modified polyolefin in advance using a blender. There is a method of supplying from the feeder and supplying the inorganic filler from the side feeder of the extruder. As the side feed position when performing the side feel, the length from the original loading position to the discharge port is 1, and the original loading position To 1/5 to 4/5. Moreover, after melt-kneading (A) polyamide, (B) unmodified polypropylene, and (C) -modified polyolefin in advance, a method of melt-kneading the inorganic filler can also be mentioned.

  The polyamide resin composition of the present invention can be molded by a known method, and the molding method is not limited, and injection molding, extrusion molding, blow molding, press molding and the like can be used. Among them, it is preferable to employ one method selected from injection molding, injection compression molding, and compression molding in terms of excellent productivity and industrial implementation of the present invention.

  Since the polyamide resin composition of the present invention has a small decrease in physical properties due to water absorption, taking advantage of this characteristic, it is possible to take advantage of this characteristic, such as window regulator door knob switches, door mirrors, room mirrors, rear mirrors, etc. Covers such as steering wheel, sun visor arm, assist grip, shift knob, cylinder head cover, engine sound insulation cover, timing belt cover, various switch and sensor cases, wheel caps, fuel filler caps, car seat parts such as child seat parts, Bicycle parts, wheelchair and baby stroller parts, chair legs, armrests, handrails, window frames, door knobs, flooring and its pillars, life-related parts such as bolts and screws, furniture and building materials-related parts, and PC housings Related Applications can be suitably used in such.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited by these. Measurement methods used in Examples and Comparative Examples are shown below.

(1) Viscosity number Measured according to ISO 307.
Solvent: 96% sulfuric acid

(2) Melt flow rate (MFR)
Measurements were performed according to ISO 1133.
Measurement temperature: 230 ° C., load: 2160 g, residence time: 5 minutes.

(3) Glass transition point According to JIS K7196, an inflection point obtained from a curve (TMA curve) in which the horizontal axis obtained by thermo-mechanical analysis (TMA) is the temperature and the vertical axis is the deformation amount is the glass transition point. Went.
Temperature increase rate: 5 ° C./min.

(4) Mechanical strength It was measured according to the following standard method.
Tensile strength, elongation at break (23 ° C., absolutely dry): ISO 527-1, ISO 527-2
Tensile strength, tensile elongation at break (23 ° C., equilibrium water absorption): ISO 527-1, ISO 527-2
Flexural strength, flexural modulus (23 ° C., absolutely dry): ISO 178
Flexural strength, flexural modulus (23 ° C., equilibrium water absorption): ISO 178
Charpy impact strength (notched) (23 ° C., absolutely dry): ISO 175.

(5) Appearance of molded product The surface of a square plate obtained by injection-molding a square plate (film gate) of 80 × 80 × 3 (mm) was visually confirmed and evaluated by surface smoothness and gloss.
◎ Smooth surface and excellent gloss.
○ The surface is smooth and shiny.
Δ: The surface is not smooth and glossy.
X The smoothness of the surface is poor and there is no gloss.

Reference Example 1 (A1) Manufacturing Method of Polyamide 66 (A1) Polyamide 66 used in Examples and Comparative Examples was polymerized by the following method.

  Hexamethylenediamine, 1500 g of adipic acid and 375 g of ion-exchanged water were weighed and charged into a polymerization can, and the reaction was carried out at a final temperature of 260 ° C. while stirring under normal pressure and nitrogen flow. The polymer discharged into the water bath was pelletized with a strand cutter. The obtained pellets were treated in hot water at 95 ° C. for 20 hours to extract and remove unreacted monomers and low polymer. The pellet after extraction was dried at 80 ° C. for 50 hours or more. As a result of measuring the viscosity number of the obtained pellet, it was 140 ml / g.

Reference Example 2 (A2) Production Method of Polyamide 6 (A2) Polyamide 6 used in Examples and Comparative Examples was polymerized by the following method.

  ε-Caprolactam (10,000 g), benzoic acid (2.16 g), and ion-exchanged water (200 g) were weighed and charged in a polymerization vessel, and the mixture was allowed to react for 12 hours at a final ultimate temperature of 250 ° C. with stirring under normal pressure and nitrogen flow. The polymer discharged into the water bath was pelletized with a strand cutter. The obtained pellets were treated in hot water at 95 ° C. for 15 hours to extract and remove unreacted monomers and low polymer. The pellet after extraction was dried at 80 ° C. for 50 hours or more. It was 130 ml / g as a result of measuring the viscosity number of the obtained pellet.

[Example 1]
70 parts by weight of (A1) polyamide 66 produced by the polymerization method shown in Reference Example 1 and 25 parts by weight of (B) unmodified polypropylene [manufactured by Prime Polymer Co., Ltd .: trade name E111G], MFR 50 g / 10 min. MFR 50 g / 10 min, (C) modified polyolefin having a glass transition point of −14 ° C. [Mitsui Chemicals Co., Ltd. product name: TX1370] 5 parts by weight of a mixture obtained by dry blending with a tumbler, glass fiber [Nippon Electric Glass Co., Ltd .: Trade name: T-289] was melt kneaded at a ratio of 55 parts by weight using a twin screw extruder (manufactured by Werner Pfleiderer: ZSK57) at a cylinder set temperature of 290 ° C. and a screw speed of 200 rpm. went. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 290 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, a parallel part flow rate of 200 mm / second, by an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

[Examples 2-3]
In the same manner as in Example 1, except that (A1) polyamide 66, (B) unmodified polypropylene, and (C) modified polyolefin shown in Example 1 have the blending ratios shown in Table 1, pellets and molded articles were obtained. Obtained and investigated various properties.

[Example 4]
70 parts by weight of (A2) polyamide 6 produced by the polymerization method shown in Reference Example 2 and 25 parts by weight of (B) unmodified polypropylene [manufactured by Prime Polymer Co., Ltd .: trade name E111G], MFR 50 g / 10 min. MFR 50 g / 10 min, (C) modified polyolefin having a glass transition point of −14 ° C. [Mitsui Chemicals Co., Ltd. product name: TX1370] 5 parts by weight of a mixture obtained by dry blending with a tumbler, glass fiber [Nippon Electric Glass Co., Ltd .: Trade name: T-289] was melt kneaded at a ratio of 55 parts by weight using a twin screw extruder (manufactured by Werner Pfleiderer: ZSK57) at a cylinder set temperature of 260 ° C. and a screw rotation speed of 200 rpm. went. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 260 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, and a parallel part flow rate of 200 mm / sec. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

[Examples 5 to 6]
In the same manner as in Example 2, except that (A2) polyamide 6 and (B) unmodified polypropylene and (C) modified polyolefin shown in Example 2 had the blending ratios shown in Table 1, pellets and molded articles were obtained. Obtained and investigated various properties.

[Comparative Example 1]
70 parts by weight of (A1) polyamide 66 produced by the polymerization method shown in Reference Example 1 and (B) unmodified polypropylene (manufactured by Prime Polymer Co., Ltd .: trade name E111G) of 30 parts by weight of TBR Using a biaxial extruder (Werner Pfleiderer: ZSK57) at a ratio of 55 parts by weight of glass fiber [manufactured by Nippon Electric Glass Co., Ltd .: trade name T-289] with respect to 100 parts by weight of the dry-blended mixture. Melt kneading was performed under conditions of a cylinder set temperature of 290 ° C. and a screw rotation speed of 200 rpm. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 290 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, a parallel part flow rate of 200 mm / second, by an injection molding machine NEX1000 manufactured by Nissei Plastic Industry. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

[Comparative Example 2]
50 parts by weight of (A1) polyamide 66 produced by the polymerization method shown in Reference Example 1, 45 parts by weight of (B) unmodified polypropylene [manufactured by Prime Polymer Co., Ltd .: trade name E111G], MFR 50 g / 10 min. MFR 50 g / 10 min, (C) modified polyolefin having a glass transition point of −14 ° C. [Mitsui Chemicals Co., Ltd. product name: TX1370] 5 parts by weight of a mixture obtained by dry blending with a tumbler, glass fiber [Nippon Electric Glass Co., Ltd .: Trade name: T-289] was melt kneaded at a ratio of 55 parts by weight using a twin screw extruder (manufactured by Werner Pfleiderer: ZSK57) at a cylinder set temperature of 290 ° C. and a screw speed of 200 rpm. went. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 290 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, a parallel part flow rate of 200 mm / second, by an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

[Comparative Example 3]
5 parts by weight of ethylene-propylene copolymer having an MFR of 0.6 g / 10 min and a glass transition point of −40 ° C., 0.8 parts by weight of maleic anhydride, 2,5-dimethyl-2,5-di (t-butylperoxy) ) Melt-kneading was performed at a ratio of 0.2 parts by weight of hexane using a twin screw extruder (manufactured by Werner Pfleiderer: ZSK57) at a cylinder setting temperature of 200 ° C. and a screw rotation speed of 200 rpm. After melt-kneading, pellets of ethylene-propylene copolymer that was hot cut and modified with maleic anhydride were obtained. The obtained maleic anhydride-modified ethylene-propylene copolymer had an MFR of 0.6 g / min and a glass transition point of -40 ° C.

  70 parts by weight of (A1) polyamide 66 produced by the polymerization method shown in Reference Example 1 and 25 parts by weight of (B) unmodified polypropylene [manufactured by Prime Polymer Co., Ltd .: trade name E111G], MFR 50 g / 10 min. To 100 parts by weight of a mixture obtained by dry blending 5 parts by weight of the maleic anhydride-modified ethylene-propylene copolymer obtained with a tumbler, 55 glass fibers [manufactured by Nippon Electric Glass Co., Ltd .: trade name T-289] Using a twin screw extruder (manufactured by Werner Pfleiderer: ZSK57) at a ratio of parts by weight, melt blending was performed under conditions of a cylinder set temperature of 290 ° C. and a screw rotation speed of 200 rpm. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 290 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, a parallel part flow rate of 200 mm / second, by an injection molding machine NEX1000 manufactured by Nissei Plastic Industry. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

[Comparative Example 4]
70 parts by weight of (A2) polyamide 6 produced by the polymerization method shown in Reference Example 2 and 30 parts by weight of (B) unmodified polypropylene [manufactured by Prime Polymer Co., Ltd .: trade name E111G], MFR 50 g / 10 min. Using a biaxial extruder (Werner Pfleiderer: ZSK57) at a ratio of 55 parts by weight of glass fiber [manufactured by Nippon Electric Glass Co., Ltd .: trade name T-289] with respect to 100 parts by weight of the dry-blended mixture. Melt kneading was performed under conditions of a cylinder set temperature of 260 ° C. and a screw rotation speed of 200 rpm. At that time, the glass fiber was side-feeded with the dry blended mixture. As the side feed position, the length from the original loading position to the discharge port was set to 1, and the position was 3/5 from the original loading position. After melt-kneading, the strand-shaped gut was cooled with a cooling bath, and pellets were obtained using a cutter. According to ISO1874-2, the obtained pellets were set at a cylinder setting temperature of 260 ° C., a mold surface temperature of 80 ° C., a screw rotation speed of 120 rpm, and a parallel part flow rate of 200 mm / sec. Test pieces of ISO Type-A standard were molded under the conditions of injection / cooling = 20/20 seconds, and various characteristics were examined by the measurement methods described above. The results are shown in Table 1.

  From Examples 1 to 6 and Comparative Examples 1 to 4, a molded article of a polyamide resin composition obtained by blending glass fibers into (A) polyamide, (B) unmodified polypropylene, and (C) modified polyolefin is polyamide. It was confirmed that the material exhibits the excellent rigidity and impact characteristics inherent to the resin, while suppressing deterioration of physical properties due to water absorption and good appearance.

Claims (4)

(A), (B), and (C) as a total of 100% by weight, (A) 55-90% by weight polyamide, (B) 9-45% by weight unmodified polypropylene, (C) 1-10% by weight modified polyolefin %, The viscosity number obtained according to ISO 307 (96% sulfuric acid method) of polyamide (A) is 100 to 200 ml / g, and (B) ISO 1133 of unmodified polypropylene ( Melt flow rate measured in accordance with ISO 1133 of a modified polyolefin (temperature 230 ° C., residence time 5 min, load 2160 g) measured at 230 ° C., residence time 5 min, load 2160 g) 20-80g / 10min, measured according to JIS K7196 (heating rate 5 ° C / min) Polyamide resin composition having a glass transition point is characterized by a -20 to 0 ° C.. The polyamide resin composition according to claim 1, wherein the total of (A), (B), and (C) according to claim 1 is 100 parts by weight, and 10 to 150 parts by weight of an inorganic filler is blended. The polyamide resin composition according to claim 1 or 2, wherein (A) the polyamide is (A1) polyamide 66 or (A2) polyamide 6. The molded object which consists of polyamide in any one of Claims 1-3.