JP2008231406A - Polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition comprising a polyamide resin and a platy inorganic reinforcement and excellent in toughness and high-temperature rigidity. <P>SOLUTION: The polyamide resin composition comprises a polyamide resin which is composed of (A) polyamide 66 and (B) at least one selected from among polyamide 6, polyamide 610 and polyamide 612, has a weight ratio of (A)/(B) of 60/40-90/10, and contains a platy inorganic reinforcement having an average particle size of 3 μm or less and in an amount of 20-50 wt.% in terms of inorganic ash content. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyamide resin composition. Specifically, the present invention relates to a polyamide resin composition having both toughness and high-temperature rigidity comprising a polyamide resin and an inorganic reinforcing material.

  Conventionally, inorganic reinforcing materials such as glass fibers, glass beads, talc, mica and clay have been used for the purpose of increasing the rigidity of polyamide resins. Although these inorganic reinforcing materials can achieve high rigidity, there is a problem that toughness such as tensile elongation and impact resistance is lowered. Therefore, as a prescription that achieves both high rigidity and toughness, a friction welding resin material containing an inorganic filler in a polyamide 6/66 copolymer has been proposed. (Patent Document 1) However, since the melting point is lowered with copolymerization, there is a problem that rigidity at high temperature is lowered. In addition, a resin composition for friction welding molding comprising a polyamide resin blended with polyamide 6 and an aliphatic polyamide copolymer and / or an aliphatic polyamide terpolymer and an inorganic reinforcing material has been proposed. (Patent Document 2) However, since the copolymer 6 is blended with the polyamide 6, the toughness is improved, but the decrease in rigidity at high temperature has not been solved.

The above-described high temperature characteristics are affected by the crystallinity of the base polymer and the lowering of the melting point. Therefore, a resin composition composed of an aromatic polyamide having a high crystallinity and a high melting point and wollastonite has been proposed (Patent Document 3). The aromatic polyamide used in Patent Document 3 has a problem of low toughness due to high crystallinity and high rigidity at high temperatures because of high crystallinity and melting point.
Japanese Patent Laid-Open No. 9-128772 JP 11-293105 A JP 2001-106908 A

  Therefore, the present invention solves the above-mentioned problems, that is, a polyamide resin composition that exhibits an extremely excellent property of uniformly dispersing kaolin in the polyamide resin without agglomerating to achieve both toughness and rigidity at high temperature. The task is to get things.

  As a result of intensive studies in order to solve the above problems, the present inventors have achieved extremely excellent properties that both toughness and rigidity at high temperature can be achieved by melt-kneading kaolin having a specific average particle diameter with polyamide resin. The present inventors have found that a polyamide resin composition expressing the above can be obtained, and have reached the present invention.

That is, the present invention
1. A polyamide comprising (A) polyamide 66 and (B) at least one selected from polyamide 6, polyamide 610 and polyamide 612, wherein the weight ratio of (A) and (B) is 60:40 to 90:10 A polyamide resin composition comprising 20-50% by weight of a resin mixture and a plate-like inorganic reinforcing material having an average particle size of 3 μm or less, based on the total of the polyamide resin mixture and the inorganic reinforcing material,
2. 2. The polyamide resin composition according to 1, wherein the inorganic reinforcing material is at least one selected from kaolin, mica and talc; The polyamide resin composition according to 1 or 2, wherein the polyamide resin composition has a relative viscosity of 2.3 to 4.0,
It is.

  According to the present invention, at least one selected from kaolin, mica, and talc having a specific particle size in a specific polyamide resin is uniformly dispersed without agglomeration, and the resin has both toughness and rigidity at high temperature. Since the composition can be obtained, it is suitable for molded products such as automobile parts, electrical / electronic parts, building materials, furniture, and daily goods.

  The present invention will be described in detail below.

  The polyamide resin mixture used in the present invention is at least one mixture selected from (A) polyamide 66 and (B) polyamide 6, polyamide 610 and polyamide 612.

  Here, (A) polyamide 66 resin is a polycondensate mainly composed of hexamethylenediamine and adipic acid, and (B) polyamide 6, polyamide 610 or polyamide 612 resin is lactam, hexamethylene diamine, sebacic acid, dodecane. It is a polyamide resin mainly composed of diacid.

  Moreover, the composition ratio of the polyamides (A) and (B) can be used in a weight ratio of 60:40 to 90:10, and more preferably 70:30 to 90:10. (A) If the composition ratio of the polyamide 66 is less than 60 by weight, the rigidity at high temperature is significantly reduced, and if it exceeds 90, the toughness is insufficient.

  As the degree of polymerization of the polyamide resin, those having a relative viscosity of 2.3 to 4.0 measured at 25 ° C. in a 1% by weight 98% sulfuric acid solution can be preferably used. Is in the range of ~ 3.1. If the relative viscosity is less than 2.3, sufficient toughness cannot be obtained, and if it exceeds 4.0, the fluidity is low, so the inorganic reinforcing material cannot be uniformly dispersed and sufficient toughness cannot be obtained. .

  The relative viscosity of the polyamide resin composition in the present invention is measured at a polyamide resin concentration of 1% by weight after dissolving the polyamide resin composition in 98% sulfuric acid at 25 ° C., removing the inorganic reinforcing material with a centrifuge. Relative viscosity.

  The inorganic reinforcing material used in the present invention may be a plate-like inorganic reinforcing material generally used for polyamide resins, and glass flakes, talc, kaolin, mica, and the like can be used. Among them, kaolin, talc and mica having a fine average particle diameter are preferable, but kaolin is more preferable in order to achieve both toughness and rigidity at high temperature. Further, the inorganic reinforcing material is more preferably treated with silane, titanate, zirconate, or other coupling agent in order to improve the adhesion to the polyamide resin.

The average particle diameter of the inorganic reinforcing material can be 3 μm or less, and more preferably 2 μm or less. When the average particle size exceeds 3 μm, the toughness is lowered and the object of the present invention cannot be achieved. The lower limit of the average particle size is 0.1 μm.
The average particle size of the inorganic reinforcing material in the present invention is an average particle size obtained from a particle size distribution obtained by a liquid phase precipitation method in which a solid is dispersed in a liquid and a particle size distribution is obtained by a difference in sedimentation speed. .

  The blending ratio of the inorganic reinforcing material can be 20 to 50% by weight, more preferably 30 to 40% by weight, based on the total of the polyamide resin mixture and the inorganic reinforcing material. If it exceeds 50% by weight, the toughness is greatly reduced, and the object of the present invention cannot be achieved.

  In addition, the resin composition of the present invention includes a known coloring agent, an antioxidant such as hindered phenol and hindered amine, a release agent such as ethylene bisstearyl amide and higher fatty acid ester, as long as the target effect is not impaired. Additives such as heat stabilizers such as epoxy compounds, plasticizers, copper compounds, lubricants, UV inhibitors, colorants, flame retardants, and the like can be contained. Specific examples of copper compounds include cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, cupric iodide, cupric sulfide, nitric acid. Cupric, copper phosphate, cuprous acetate, cupric acetate, cupric salicylate, cupric stearate, cupric benzoate and inorganic copper halides and xylylenediamine, 2-mercaptobenzimidazole And complex compounds such as benzimidazole. Among these, monovalent copper compounds, particularly monovalent copper halide compounds are preferable, and cuprous acetate, cuprous iodide, and the like are preferably used. The addition amount of these copper compounds is usually preferably 0.01 to 2 weights, more preferably 0.015 to 1 weight parts, with respect to 100 weight% of the polyamide resin. If the amount added is too large, metal copper is liberated during melt molding, and the value of the product may be reduced by coloring. In the present invention, it is also possible to add an alkali halide in combination with a copper compound. Examples of the alkali halide compound include lithium chloride, lithium bromide, lithium iodide, potassium chloride, potassium bromide, potassium iodide, sodium bromide and sodium iodide. Sodium chloride is particularly preferred.

  The polyamide resin composition of the present invention is produced by a method of melt-kneading two or more kinds of polyamide resins and an inorganic reinforcing material having an average particle size of 3 μm or less. There is no limitation on the method of melt kneading, and it is sufficient that mechanical shearing can be performed in the molten state of the polyamide resin. The treatment method may be either a batch type or a continuous type, but a continuous type capable of continuous production is preferred from the viewpoint of productivity. Although there is no restriction | limiting also in a concrete kneading apparatus, An extruder, especially a twin-screw extruder are preferable in terms of productivity. Although there is no restriction | limiting in particular also in screw arrangement, It is preferable to provide a kneading zone in order to disperse | distribute a plate-shaped inorganic reinforcement material more uniformly. It is also preferable to provide a vent port in the melt-kneading apparatus for the purpose of removing moisture generated during melt-kneading and low molecular weight volatile components.

  The polyamide resin composition of the present invention can be easily formed into a molded product by a usual processing method such as extrusion molding or injection molding. Since the obtained molded product has toughness and rigidity at high temperature, it is suitable for various engineering parts and structural materials.

  Examples of specific applications in which the present invention is preferably used include various gears, various cases, sensors, connectors, sockets, resistors, relay case switch coil bobbins, housings, electrical / electronic parts represented by computer-related parts, VTRs, TVs, irons, hair dryers, rice cookers, microwave ovens, audio equipment, lighting equipment, refrigerators, air conditioners, typewriters, word processors, home appliances such as office electrical product parts, oilless bearings, stern bearings, underwater bearings, etc. Various bearings, motor parts, lighters, various bolts and nuts, electric tool housings, machine-related parts such as wheels for bicycles, tricycles, snowmobiles, alternator terminals, alternator connectors, IC regulators, potentiometer bases for light dials Various valves such as exhaust gas valves, various pipes related to fuel, exhaust system, intake system, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil Temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts , Distributor, starter switch, starter relay, wire harness connector, window washer Nozzle, air conditioning panel switch board, coil for fuel-operated electromagnetic valve, connector for fuse, horn terminal, electrical component insulation plate, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition Equipment cases, relay boxes, junction boxes, wheel caps, clips, fasteners, engine covers, cylinder head covers, timing belt covers, radiator tanks, fuel tanks, oil tanks and other automotive / vehicle-related parts, housing interior / exterior parts, structures Materials, building materials such as sash parts, furniture-related parts such as chair legs.

The following examples further illustrate the present invention.
Evaluation item and measuring method Relative viscosity: In a sulfuric acid concentration of 98%, the inorganic reinforcing material was removed with a centrifuge at 25 ° C., and the relative viscosity was measured at a concentration of 1% by weight.

  Inorganic ash content: Measured according to the direct ashing method of ISO3451-1 and -4.

  Tensile elongation: An ISO 3167 multipurpose test piece A was prepared using an injection molding machine (NEX1000 manufactured by Nissei Plastic Industry Co., Ltd.) under conditions of a cylinder temperature of 290 to 300 ° C. and a mold temperature of 80 ° C. -2 was measured (test speed: 5 mm / min, distance between grippers: 115 mm).

  Charpy impact strength: Using an injection molding machine (Nex 1000 manufactured by Nissei Plastic Industry Co., Ltd.), an ISO 3167 multipurpose test piece A type was produced under conditions of a cylinder temperature of 290 to 300 ° C. and a mold temperature of 80 ° C. Measurements were performed according to the above. The test piece used was subjected to single notch processing with a depth of 2 mm and measured by edgewise impact.

  Bending elastic modulus: Using an injection molding machine (NEX1000 manufactured by Nissei Plastic Industry Co., Ltd.), an ISO 3167 multipurpose test piece A type was prepared under the conditions of a cylinder temperature of 290 to 300 ° C. and a mold temperature of 80 ° C., in accordance with ISO 178 (Test speed: 2 mm / min, distance between fulcrums: 64 mm).

  Deflection temperature under load: An ISO 3167 multipurpose test piece A type was prepared using an injection molding machine (NEX1000 manufactured by Nissei Plastic Industry Co., Ltd.) under conditions of a cylinder temperature of 290 to 300 ° C. and a mold temperature of 80 ° C. Measurement (bending stress: 1.80 MPa) was performed according to the above.

Example 1
(A) Polyamide 66-A (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.9) and (B) Polyamide 6-A (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.8) in the weight ratio shown in Table 1. 60% by weight of the blended polyamide resin and 40% by weight of kaolin (Polarite 102A manufactured by Sakai Kogyo Co., Ltd.) were dry blended with a tumbler mixer.

  After that, set the cylinder temperature to 290 ° C with a twin screw extruder (TEX30 type manufactured by Nippon Steel Works), melt and knead at a screw speed of 250 rpm, cool with a water-cooled bath, and then pellet with a strand cutter Turned into. Thereafter, vacuum drying was performed in a vacuum state using a vacuum dryer at a processing temperature of 80 ° C. and a processing time of 12 hours, and the moisture content was adjusted to 0.07% or less.

  The evaluation results of the obtained samples are as shown in Table 1. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Examples 2-3
A polyamide resin composition was obtained in the same manner as in Example 1 except that (A) polyamide 66-A and (B) polyamide 6-A were in the weight ratio shown in Table 1.

  The evaluation results of the obtained samples are shown in Table 1. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Example 4
(B) A polyamide resin composition was obtained in the same manner as in Example 1 except that polyamide 610 (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.7) was used.

  The evaluation results of the obtained samples are shown in Table 1. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Comparative Example 1
(B) A polyamide resin composition was obtained in the same manner as in Example 1 except that polyamide 6-A was not used.

  The evaluation results of the obtained samples are shown in Table 1. Tensile elongation and Charpy impact strength were poor.

Comparative Example 2
A polyamide resin composition was obtained in the same manner as in Example 1 except that (A) polyamide 66-A and (B) polyamide 6-A were in the weight ratio shown in Table 1.

  The evaluation results of the obtained samples are shown in Table 1. The rigidity at high temperature was inferior.

Comparative Example 3
A polyamide resin composition was obtained in the same manner as in Example 1 except that wollastonite (FPWSH400S manufactured by Kinsei Matec Co., Ltd.) was used.

  The evaluation results of the obtained samples are shown in Table 1. Tensile elongation and Charpy impact strength were poor.

Example 5
A polyamide resin composition was obtained in the same manner as in Example 1 except that kaolin (Translink 555 manufactured by Hayashi Kasei Co., Ltd.) was used.

  The evaluation results of the obtained samples are shown in Table 2. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Comparative Example 4
A polyamide resin composition was obtained in the same manner as in Example 1 except that kaolin (ASP400P manufactured by Hayashi Kasei Co., Ltd.) was used.

  The evaluation results of the obtained samples are shown in Table 2. Tensile elongation and Charpy impact strength were poor.

Examples 6-7
A polyamide resin composition was obtained in the same manner as in Example 1 except that the amount of the kaolin inorganic reinforcement was changed to Table 2.

  The evaluation results of the obtained samples are shown in Table 2. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Comparative Examples 5-6
A polyamide resin composition was obtained in the same manner as in Example 1 except that the amount of the kaolin inorganic reinforcement was changed to Table 2.

  The evaluation results of the obtained samples are shown in Table 2. Comparative Example 5 was inferior in rigidity at high temperature, and Comparative Example 6 was inferior in tensile elongation and Charpy impact strength.

Example 8
(A) Polyamide 66-B (Amilan manufactured by Toray Industries, Inc., relative viscosity 3.8) and (B) Polyamide 6-B (Amilan manufactured by Toray Industries, Inc., relative viscosity 3.9) were used. 1 to obtain a polyamide resin composition.

  The evaluation results of the obtained samples are shown in Table 3. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Example 9
(A) Polyamide 66-C (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.3) and (B) Polyamide 6-C (Amilan manufactured by Toray Industries, Inc., relative viscosity 2.4) polymerized according to conventional methods are used. A polyamide resin composition was obtained in the same manner as in Example 1 except that.

  The evaluation results of the obtained samples are shown in Table 3. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Comparative Example 7
(A) Polyamide 66-E (Amilan, Toray Industries, Inc., relative viscosity 4.4) and (B) Polyamide 6-B (Amilan, Toray Industries, Inc., relative viscosity 3.9) polymerized according to a conventional method are used. A polyamide resin composition was obtained in the same manner as in Example 1 except that the amount of the kaolin inorganic reinforcing material was changed to Table 3.

  The evaluation results of the obtained samples are shown in Table 3. The kaolin was not sufficiently dispersed, and the tensile elongation and Charpy impact strength were poor.

Comparative Example 8
(A) Polyamide 66-D (Amilan manufactured by Toray Industries Inc., relative viscosity 2.0) and (B) Polyamide 6-C (Amilan manufactured by Toray Industries Inc., relative viscosity 2.4) polymerized according to a conventional method are used. A polyamide resin composition was obtained in the same manner as in Example 1 except that the amount of the kaolin inorganic reinforcing material was changed to Table 3.
The evaluation results of the obtained samples are shown in Table 3. Tensile elongation and Charpy impact strength were poor.

Example 10
A polyamide resin composition was obtained in the same manner as in Example 1 except that mica (A-11 manufactured by Yamaguchi Mica Co., Ltd.) was used.

  The evaluation results of the obtained samples are shown in Table 3. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

Example 11
A polyamide resin composition was obtained in the same manner as in Example 1 except that talc (SG-95 manufactured by Nippon Talc Co., Ltd.) was used.

  The evaluation results of the obtained samples are shown in Table 3. While maintaining rigidity, it was possible to achieve both toughness and high-temperature rigidity.

  The polyamide resin composition according to the present invention can achieve both toughness and rigidity at high temperature by using a specific polyamide resin composition and a plate-like inorganic reinforcing material. The obtained polyamide resin composition is widely used in automobile parts, electrical / electronic parts, building materials, furniture, and daily goods.

Claims (3)

A polyamide comprising (A) polyamide 66 and (B) at least one selected from polyamide 6, polyamide 610 and polyamide 612, wherein the weight ratio of (A) and (B) is 60:40 to 90:10 A polyamide resin composition comprising 20-50% by weight of a resin mixture and a plate-like inorganic reinforcing material having an average particle size of 3 μm or less, based on the total of the polyamide resin mixture and the inorganic reinforcing material. The polyamide resin composition according to claim 1, wherein the inorganic reinforcing material is at least one selected from kaolin, mica, and talc. The polyamide resin composition according to claim 1 or 2, wherein the polyamide resin composition has a relative viscosity of 2.3 to 4.0.