Resin composition and molded article

Abstract

A resin composition including an aromatic polyether ketone resin (I), and a fluororesin (II), the fluororesin (II) being a copolymer of tetrafluoroethylene and a perfluoroethylenic unsaturated compound represented by the following formula (1):
CF.sub.2CFR.sub.f.sup.1(1)
wherein R.sub.f.sup.1 represents CF.sub.3 or OR.sub.f.sup.2, and R.sub.f.sup.2 represents a C1 to C5 perfluoroalkyl group; the composition containing the aromatic polyether ketone resin (I) and the fluororesin (II) at a mass ratio (I):(II) of 95:5 to 50:50; the fluororesin (II) being dispersed as particles in the aromatic polyether ketone resin (I) and having an average dispersed particle size of 3.0 m or smaller.

Claims

1. A resin composition comprising an aromatic polyether ketone resin (I), and a fluororesin (II), the fluororesin (II) being a copolymer of tetrafluoroethylene and a perfluoroethylenic unsaturated compound represented by the following formula (1):
CF.sub.2CFR.sub.f.sup.1(1) wherein R.sub.f.sup.1 represents CF.sub.3 or OR.sub.f.sup.2, and R.sub.f.sup.2 represents a C1 to C5 perfluoroalkyl group; the composition comprising the aromatic polyether ketone resin (I) and the fluororesin (II) at a mass ratio (I):(II) of 95:5 to 50:50; the fluororesin (II) being dispersed as particles in the aromatic polyether ketone resin (I) and having an average dispersed particle size of 1.90 m or smaller, wherein the fluororesin (II) has a melt flow rate of 0.1 to 100 g/10 min, wherein the fluororesin (II) comprises 90 to 99 mol % of tetrafluoroethylene and 1 to 10 mol % of the perfluoroethylenic unsaturated compound represented by formula (1), and a molded article obtained from the resin composition has a limiting PV value of 800.Math.kPa m/s or higher.

2. The resin composition according to claim 1, wherein the fluororesin (II) has an average dispersed particle size of 0.30 m or smaller.

3. The resin composition according to claim 1, wherein the aromatic polyether ketone resin (I) is a polyether ether ketone.

4. The resin composition according to claim 1, wherein a molded article obtained from the resin composition has a limiting PV value of 1000.Math.kPa m/s or higher.

5. The resin composition according to claim 1, which comprises the aromatic polyether ketone resin (I) and the fluororesin (II) at a mass ratio (I):(II) of 90:10 to 50:50.

6. The resin composition according to claim 1, wherein the fluororesin (II) has an average dispersed particle size of 1.0 m or smaller.

Description

EXAMPLES

(1) The present invention is described in the following examples. The present invention is not limited to these examples.

(2) <Measurement of MFR>

(3) In accordance with ASTM D3307-01, the mass (g/10 min) of the polymer flowing out from the nozzle (inner diameter: 2 mm, length: 8 mm) of a melt indexer (product of Toyo Seiki Seisaku-sho, Ltd.) at 372 C. under a load of 5000 g was determined.

(4) <Production of Pressed Sheet Molded Article>

(5) The resin compositions produced in the examples and comparative examples each were compression molded in a heat press molding machine at 380 C. and 5 MPa, so that 3-mm-thick sheets were produced.

(6) <Determination of Limiting PV Value>

(7) Each pressed sheet obtained by the above method was cut into a 3 cm (length)3 cm (width)3 mm (thickness) specimen. The limiting PV value of the specimen was determined in accordance with the A method of JIS K7218, using a friction and wear tester (product of A&D Company, Limited) and a steel material S45C (#240 sandpaper finishing) as an opposite material. The speed was constant at 3 m/sec, and the surface pressure was increased by 20 N from 20 N every 10 minutes.

(8) <Measurement of Coefficient of Kinetic Friction>

(9) The coefficient of kinetic friction of the pressed sheet obtained by the method described above was determined using a ball-on-disk SRV friction wear tester (product of OPTIMOL) at room temperature and 50 Hz.

(10) <Measurement of Notched Izod Strength>

(11) In accordance with JIS K7110, a specimen for notched Izod strength measurement was cut out from the pressed sheet produced by the method described above, and the notched Izod strength was measured at room temperature using an Izod impact tester (product of Toyo Seiki Seisaku-sho, Ltd.).

(12) <Calculation of Average Dispersed Particle Size>

(13) The pressed sheet produced by the method described above was trimmed to have a 1-mm-square tip by a razor for trimming. The sheet was then fixed in the sample holder of an ultramicrotome (ULTRACUT S, product of Leica Microsystems), and the chamber was cooled with liquid nitrogen to 80 C. inside. Thereby, a 90-nm-thick ultrathin section was cut out from the specimen. The ultrathin section obtained was taken out using a platinum ring to which a 20% ethanol solution was deposited. The ultrathin section was adhered to a copper mesh sheet (product of Okenshoji Co., Ltd., 200 A, 3.0 mm).

(14) The ultrathin section adhered to the copper mesh sheet was observed using a transmission electron microscope (H7100FA, product of Hitachi, Ltd.).

(15) A negative film obtained through the microscopic observation was scanned into an electronic image using a scanner (GT-9400UF, product of EPSON). The electronic image was binarized by an optical analyzer (LUZEX AP, product of Nireco), so that the average dispersed particle size of the dispersed phase was determined.

(16) The following materials were used in the examples and comparative examples.

(17) Aromatic polyether ketone resin (I): Polyether ether ketone (trade name: 450G, product of Victrex Japan Inc.)

(18) Fluororesin (II-1): Tetrafluoroethylene/hexafluoropropylene copolymer (composition weight ratio: tetrafluoroethylene/hexafluoropropylene/perfluoro(propyl vinyl ether)=87.5/11.5/1.0, MFR: 27 g/10 min)

(19) Fluororesin (II-2): Tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (composition weight ratio: tetrafluoroethylene/perfluoro(propyl vinyl ether)=94.5/5.5, MFR: 23 g/10 min)

(20) Fluororesin (III): Polytetrafluoroethylene (trade name: LUBRON L5, product of Daikin Industries, Ltd.)

(21) Fluororesin (IV): Ethylene/tetrafluoroethylene copolymer (trade name: Neoflon EP541, product of Daikin Industries, Ltd.)

Examples 1 and 2

(22) A melt-kneading device (trade name: Labo Plastomill, product of Toyo Seiki Seisaku-sho, Ltd.) was charged with the aromatic polyether ketone resin (I) and the fluororesin (II) at the ratio (parts by mass) shown in Table 1. The materials were melt-kneaded for 10 minutes at a temperature of 380 C. and a screw rotational speed of 80 rpm, whereby a resin composition was produced. The obtained resin composition was formed into a pressed sheet by the method described above, and the limiting PV value, coefficient of kinetic friction, and notched Izod strength of the sheet were determined. Also, an ultrathin section was cut out from the pressed sheet, so that the average dispersed particle size of the fluororesin (II) was calculated.

Examples 3 to 6

(23) The aromatic polyether ketone resin (I) and the fluororesin (II) were preliminarily mixed at the ratio (parts by mass) shown in Table 1. Then, the mixture was melt-kneaded by a twin screw extruder (15 mm, L/D=60) at a cylinder temperature of 380 C. and a screw rotation speed of 350 rpm, whereby a resin composition was produced. The obtained resin composition was formed into a specimen by the method described above, and the limiting PV value, coefficient of kinetic friction, and notched Izod strength were determined. The average dispersed particle size of the fluororesin (II) was also calculated.

Comparative Example 1

(24) A specimen was produced by the method described above from only the aromatic polyether ketone resin (I), and the limiting PV value, coefficient of kinetic friction, and notched Izod strength were determined.

Comparative Examples 2 and 3

(25) The aromatic polyether ketone resin (I) and the fluororesin (III) or fluororesin (IV) were preliminarily mixed at the ratio (parts by mass) shown in Table 1. Then, the mixture was melt-kneaded by a twin screw extruder (15 mm, L/D=60) at a cylinder temperature of 380 C. and a screw rotation speed of 350 rpm, whereby a resin composition was produced. The obtained resin composition was formed into a pressed sheet by the method described above, and the limiting PV value, coefficient of kinetic friction, and notched Izod strength were determined. Also, an ultrathin section was cut out from the pressed sheet, so that the average dispersed particle size of the fluororesin (II) was calculated.

(26) TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 Example 3 Polyether ketone resin (I) 80 80 80 60 80 60 100 80 80 Fluororesin (II-1) 20 20 40 Fluororesin (II-2) 20 20 40 Fluororesin (III) 20 Fluororesin (IV) 20 Average dispersed particle 1.54 1.90 0.13 0.22 0.18 0.25 73 2.80 size (m) Limiting PV value (kPa .Math. m/s) 900 1000 1500 1600 1700 1950 750 600 750 Coefficient of kinetic friction 0.21 0.19 0.18 0.16 01.17 0.15 0.24 0.15 0.23 Notched Izod strength (kJ/m.sup.2) 17 17 55 70 50 70 17 18 15

(27) The results of Comparative Example 3 show that use of an ethylene/tetrafluoroethylene copolymer as a fluororesin improves neither the coefficient of kinetic friction nor the wear resistance. Addition of polytetrafluoroethylene decreased the coefficient of kinetic friction as seen from the results of Comparative Example 2, but did not affect the wear resistance.

INDUSTRIAL APPLICABILITY

(28) The resin composition of the present invention is suitable for molding materials used for components such as automobile components, industrial components, and electrical and electronic components which are required to have high sliding properties.