JP6889912B2 - Polyamide resin composition and molded article obtained by molding the polyamide resin composition - Google Patents

Description

The present invention relates to a polyamide resin composition having excellent mechanical properties and abrasion resistance.

Polyamide resins are widely used in various industrial fields such as automobiles, machinery, and electrical / electronic because they have excellent properties as engineering plastics. In recent years, polyamide resins have come to be widely used as a metal substitute for sliding parts such as bearings, gears, worms, and sliding cylinders because of their excellent mechanical properties and wear resistance. Under high speed conditions, there is a problem that the abrasion resistance is insufficient. Therefore, it has been studied to add various reinforcing materials and additives to the polyamide resin to improve the mechanical properties and slidability.

Patent Documents 1 and 2 disclose that tetrafluoroethylene and high-density polyethylene are blended in a polyamide resin to improve abrasion resistance, and Patent Documents 3 and 4 contain an elastomer and a filler in a polyamide resin. It is disclosed that the abrasion resistance is improved.

Japanese Unexamined Patent Publication No. 62-185747 Japanese Unexamined Patent Publication No. 8-157714 Japanese Unexamined Patent Publication No. 2001-106904 Japanese Unexamined Patent Publication No. 2004-107440

An object of the present invention is to provide a polyamide resin composition having excellent mechanical properties and abrasion resistance properties in view of the prior art.

As a result of diligent studies to solve such a problem, the present inventors have found that the above object can be achieved by using a glass fiber having a specific fiber diameter by using a mixture of a specific polyamide resin. The present invention has been reached.
(1) A polyamide resin composition containing a polyamide resin, glass fiber and a coupling agent (excluding a resin composition containing a modified polyolefin resin) .
The polyamide resin is a mixture of two or more types of polyamide resins, and the relative viscosity of the mixture measured at 25 ° C. and a concentration of 1 g / dl using 96% by mass concentrated sulfuric acid as a solvent is 2.8 or more. Yes, the difference in relative viscosity between the polyamide resin having the highest relative viscosity and the polyamide resin having the lowest relative viscosity among the mixtures is 0.5 or more.
The average fiber diameter of the glass fiber Ri 6.0~9.0μm der,
Coupling agent, the polyamide resin composition, wherein the γ- isocyanate propyl trimethoxysilane der Rukoto.
(2) Polyamide resin composition according to 2 or more polyamides resins, characterized in that both a polyamide 66 (1).
(3) The polyamide resin composition according to (1), wherein the two or more kinds of polyamide resins are all polyamide 6.
(4) A molded product obtained by molding the polyamide resin composition according to any one of (1) to (3).
(5) The molded body according to (4), which is a sliding component.
(6) The molded body according to (4), which is a gear, a pulley, a cam, a bearing or a cable housing.

According to the present invention, it is possible to provide a polyamide resin composition having excellent mechanical properties and abrasion resistance. The polyamide resin composition of the present invention can be suitably used for sliding parts.

The polyamide resin composition of the present invention is composed of a polyamide resin, glass fibers, and a coupling agent.

The polyamide resin used in the present invention is a resin having an amide bond in the main chain. Examples of the polyamide resin include polyε-couplemid (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), and poly. Examples thereof include hexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polyundecanamid (polyamide 11), polydodecanamid (polyamide 12), and polyamide 6/66 copolymer. Of these, polyamide 66 is preferable from the viewpoint of heat resistance, strength, processability, and economy.

The polyamide resin needs to be a mixture of two or more kinds of polyamide resins. The relative viscosity of the mixture needs to be 2.8 or higher, preferably 2.8 to 3.8. If the relative viscosity of the mixture is less than 2.8, the amount of wear increases and the impact strength decreases, which is not preferable. On the other hand, when the relative viscosity of the mixture exceeds 3.8, the abrasion resistance may be inferior or the moldability may be lowered. The difference in relative viscosity between the polyamide resin having the highest relative viscosity and the polyamide resin having the lowest relative viscosity in the mixture needs to be 0.5 or more, and preferably 0.7 or more. If the difference in relative viscosity is less than 0.5, the abrasion resistance is inferior, which is not preferable. The relative viscosity of the polyamide resin having the highest relative viscosity among the mixtures is preferably 3.3 to 5.0, and more preferably 3.7 to 4.6. If the relative viscosity of the polyamide resin having the highest relative viscosity of the mixture is less than 3.3, the mechanical properties may be low, and if the relative viscosity exceeds 5.0, the dispersibility of the glass fibers is poor. Therefore, the mechanical properties may be lowered.

The glass fiber used in the present invention needs to have a fiber diameter of 6.0 to 9.0 μm from the viewpoint of mechanical properties and abrasion resistance. Glass fibers having a fiber diameter of less than 6.0 μm are not preferable because it is difficult to produce chopped strands and it is difficult to uniformly mix the glass fibers in the polyamide resin due to insufficient opening of fibers during compounding. On the other hand, when the fiber diameter exceeds 9.0 μm, the abrasion resistance becomes low, which is not preferable. The cross-sectional shape may be circular or non-circular. The non-circular cross section is not particularly limited, but usually, an eyebrows, an oval, a semicircle, an arc, a rectangle, a parallelogram, or a similar shape thereof is used. The fiber length is preferably 1 to 15 mm, more preferably 1.5 to 12 mm, and even more preferably 2 to 6 mm. The glass fiber is preferably surface-treated with a silane coupling agent, a titanium coupling agent, or another high molecular weight or low molecular weight surface treatment agent for the purpose of enhancing dispersibility and adhesion in the polyamide resin.

The content of the glass fiber is preferably 5 to 50 parts by mass and more preferably 15 to 40 parts by mass with respect to 100 parts by mass of the polyamide resin. When the content of the glass fiber is less than 5 parts by mass, the effect of improving the mechanical properties and the abrasion resistance may be small. On the other hand, if the content of the glass fiber is more than 50 parts by mass, the abrasion resistance may decrease.

As the coupling agent used in the present invention, a silane-based coupling agent is preferable, and an isocyanate silane coupling agent or an epoxy silane coupling agent is more preferable. The isocyanate silane coupling agent is a silane coupling agent containing one or more isocyanate groups per molecule. Examples of the isocyanate silane coupling agent include γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-isocyanatepropylmethyldiethoxysilane, and γ-isocyanatepropylmethyldimethoxysilane. The epoxy silane coupling agent is a silane coupling agent containing one or more epoxy groups per molecule. Examples of the epoxysilane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxy. Examples thereof include propylmethyldiethoxysilane and γ-glycidoxypropylmethyldimethoxysilane. Of these, an isocyanatesilane coupling agent is preferable, and γ-isocyanatepropyltrimethoxysilane or γ-isocyanatepropyltriethoxysilane is more preferable.

The content of the coupling agent is preferably 0.1 to 1 part by mass, and more preferably 0.2 to 0.5 part by mass with respect to 100 parts by mass of the polyamide resin. When the content of the coupling agent is less than 0.1 parts by mass, the effect of improving the abrasion resistance may be small. On the other hand, when the content of the coupling agent is more than 1 part by mass, the tensile strength and the tensile elastic modulus may decrease.

The polyamide resin composition of the present invention may contain a heat stabilizer. Examples of the heat stabilizer include copper chloride, copper bromide, copper fluoride, copper iodide, copper thiocyanate, copper nitrate, copper acetate, naphthenic copper, copper caprice, copper laurate, copper stearate, and copper acetylacetone. , Copper (I), and copper (II) oxide. The heat stabilizer may be used alone or in combination of two or more. Of these, copper halide such as copper iodide or copper acetate is preferable from the viewpoint of improving heat resistance. The copper-based heat stabilizer can be further improved in heat resistance by being used in combination with potassium halide. Examples of potassium halide include potassium iodide, potassium bromide, and potassium chloride.

The polyamide resin composition of the present invention contains a plasticizer, an impact resistant material, a heat resistant material, a foaming agent, a weather resistant agent, a crystal nucleating agent, a crystallization accelerator, a mold release agent, and a lubricant as long as the effects of the present invention are not impaired. , Antistatic agents, flame retardants, flame retardant aids, pigments, dyes and other additives may be added.

The polyamide resin composition of the present invention can be produced by melt-kneading a polyamide resin, glass fiber, and a coupling agent with a uniaxial or twin-screw extruder, a Banbury mixer, or the like. Then, by molding the obtained polyamide resin composition composition, a molded product can be obtained. Examples of the molding method include an extrusion molding method, a blow molding method, an injection molding method and the like.

The polyamide resin composition of the present invention can be suitably used for sliding parts, particularly gears, pulleys, cams, bearings, cable housings and the like of automobiles and machines.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.
A. Evaluation method (1) Relative viscosity 96% by mass concentrated sulfuric acid was used as a solvent, and the measurement was carried out under the conditions of a temperature of 25 ° C. and a concentration of 1 g / dl.
(2) Tensile strength and tensile elastic modulus The measurement was performed at a tensile speed of 5 mm / min at room temperature in accordance with ISO527-1,2.
(3) Charpy impact strength According to ISO179-1, the measurement was performed edgewise at room temperature with a notch.

(4) Limit PV value A friction and wear test was conducted using a Suzuki type friction and wear tester (MODEL EFM-III-E type manufactured by Toyo Baldwin Co., Ltd.) in accordance with the JIS K7218 A method. Cylindrical steel (S45C, # 2000 finish) was used as the mating material, and the test speed was 200 mm / sec. A test load of 100 N was applied at the start, and the test load was increased by 100 N every 10 minutes, and the value of the load immediately before the test load in which the test piece was melted was set as the limit PV value.
In the present invention, the limit PV value is 0.6 MPa. If it was m / s or more, it was judged to be acceptable.

(5) Amount of wear A friction and wear test was carried out using a Suzuki type friction and wear tester (MODEL EFM-III-E type manufactured by Toyo Baldwin Co., Ltd.) in accordance with the JIS K7218 A method. Cylindrical steel (S45C, # 2000 finish) was used as the mating material, and the test speed was 200 mm / sec. At the start, a test load of 100 N was applied and continuous operation was performed for 1 hour.
After continuous operation, the amount of wear (g) was determined, and the amount of wear volume (cm ³ / hour) was determined using the density of the polyamide resin composition.
In the present invention, when the wear volume is 7 cm ³ / h or less, it is judged to be acceptable.

(6) Vibration fatigue test conditions are vibration fatigue tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), tensile load control, chuck distance: 25 mm, atmospheric temperature: 30 ° C, frequency: 30 Hz, stress mode: tensile conditions. The measurement was performed at. A stress of 63 MPa was applied, and the number of stress loads until the test piece broke was measured. As the test piece, a JIS K7160 type 2 test piece was used.
In the present invention, the load count is the case of 10 ⁵ or more was judged as acceptable.

B. Raw Material (1) Polyamide Resin PA6-1: Unitika E2046, Polyamide 66, Relative Viscosity 4.6
-PA6-2: Unitika E2037, polyamide 66, relative viscosity 3.7
-PA6-3: Unitika E2033, polyamide 66, relative viscosity 3.3
-PA6-4: Unitika E2000, polyamide 66, relative viscosity 2.8
-PA6-5: Unitika E2001R, polyamide 66, relative viscosity 2.5
-PA66-1: Unitika A1030BRL, polyamide 6, relative viscosity 2.5
-PA66-2: Unitika A1030BRT, polyamide 6, relative viscosity 3.5

(2) Glass fiber ・ GF1: CS03DEFT2A manufactured by Owen Corning, fiber diameter 6.5 μm, fiber length 3 mm
-GF2: CS03G459 manufactured by Nitto Boseki Co., Ltd., fiber diameter 9.0 μm, fiber length 3 mm
-GF3: Nippon Electric Glass Co., Ltd. ECS03T262H Co., Ltd. Fiber diameter 10.5 μm, Fiber length 3 mm

(3) Coupling agent ・ C1: Momentive Performance Materials Y-5187, γ-isocyanatepropyltrimethoxysilane ・ C2: Shinetsu Silicone KBM-403 γ-glycidoxypropyltrimethoxysilane
-C3: KBM-903 manufactured by Shinetsu Silicone Co., Ltd. γ-Aminopropyltrimethoxysilane

(4) Heat resistant agent, copper iodide (CuI)
・ Potassium bromide (KI)

Examples 1 to 7, 10 to 11 , Reference Examples 1 to 2 and Comparative Examples 1 to 7.
The polyamide resin and glass fiber shown in Table 1 were melt-kneaded with a TEM26SS twin-screw kneader to obtain the desired polyamide resin composition pellets.
Then, the obtained pellets were injection-molded at a cylinder temperature of 290 ° C. and a mold temperature of 80 ° C. to produce various test pieces, and various physical characteristics were evaluated.

Table 1 shows the resin compositions of Examples 1 to 7, 10 to 11 , Reference Examples 1 to 2, and Comparative Examples 1 to 7 and the evaluation of the obtained polyamide resin composition.

The polyamide resin compositions of Examples 1 to 7 and 10 to 11 had high tensile strength and Charpy impact strength, a small amount of wear, and excellent vibration fatigue resistance.

Since the polyamide resin composition of Comparative Example 1 used only one kind of high-viscosity polyamide resin as the polyamide resin, it was inferior in vibration fatigue resistance.
Since the polyamide resin composition of Comparative Example 2 used only one kind of low-viscosity polyamide resin as the polyamide resin, the amount of wear volume was large.
The polyamide resin composition of Comparative Example 3 had a large amount of wear volume because the relative viscosity of the polyamide resin mixture used was low.
The polyamide resin composition of Comparative Example 4 was inferior in vibration fatigue resistance because the difference in relative viscosity of the polyamide resin mixture used was small.
Since the polyamide resin composition of Comparative Example 5 did not use glass fibers, the limit PV value was small and the vibration fatigue property was inferior.
In the polyamide resin composition of Comparative Example 6, since the fiber diameter of the glass fiber used was large, the limit PV value was small, the amount of wear volume was large, and the vibration fatigue property was inferior.
Since the polyamide resin composition of Comparative Example 7 did not use a coupling agent, the limit PV value was small and the amount of wear volume was large.

Claims (6)

A polyamide resin composition containing a polyamide resin, glass fiber and a coupling agent (excluding a resin composition containing a modified polyolefin resin) .
The polyamide resin is a mixture of two or more types of polyamide resins, and the relative viscosity of the mixture measured at 25 ° C. and a concentration of 1 g / dl using 96% by mass concentrated sulfuric acid as a solvent is 2.8 or more. Yes, the difference in relative viscosity between the polyamide resin having the highest relative viscosity and the polyamide resin having the lowest relative viscosity among the mixtures is 0.5 or more.
The average fiber diameter of the glass fiber Ri 6.0~9.0μm der,
Coupling agent, the polyamide resin composition, wherein the γ- isocyanate propyl trimethoxysilane der Rukoto. 2 or more polyamides resins are polyamide resin composition according to claim 1, characterized in that both a polyamide 66. The polyamide resin composition according to claim 1, wherein the two or more kinds of polyamide resins are all polyamide 6. A molded product obtained by molding the polyamide resin composition according to any one of claims 1 to 3. The molded body according to claim 4, wherein the molded body is a sliding component. The molded body according to claim 4, wherein the molded body is a gear, a pulley, a cam, a bearing, or a cable housing.