JPS58160346A - Resin composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. suitable for use as a sliding material for oilless bearing, gear, can, etc., by blending an arom. polyether ketone resin, a fluorocarbon polymer and carbon fiber in a specified ratio. CONSTITUTION:95-30wt% arom. polyether ketone resin having an intrinsic viscosity of pref. 0.7-2.6, 2.5-60wt% fluorocarbon polymer such as lubricant grade polytetrafluoroethylene having an average particle size of 20mu or below, and 2.5-60wt% carbon fiber such as Magnamite AS (a product of Hercules Co.) are blended together.

Description

Detailed Description of the Invention The present invention provides a molded article with excellent sliding properties, high mechanical strength, and heat distortion temperature by blending a fluorocarbon polymer and carbon fiber with a thermoplastic aromatic polyetherketone resin. The present invention relates to a resin composition.

Thermoplastic aromatic polyetherketone resin is disclosed in Japanese Unexamined Patent Publication No. 5
It is known to have high heat resistance, flame resistance, mechanical, electrical properties, chemical resistance, and hydrolysis resistance, as seen in the description of No. 4-90296.

(1) Taking advantage of these excellent properties, it has been suggested that they can be used as insulation coatings for electric wires and cables and as flexible printed circuit boards, but they are also useful in the electronic and electrical fields, mechanical fields, aviation fields, It is expected to expand into various industrial fields such as the automobile field and the hot water field.

On the other hand, even in the above-mentioned industrial fields, there are countless parts that involve sliding of various kinds, and these parts have been made of metal or metal sintered materials combined with lubricants. Recently, plastics, especially heat-resistant plastics, have come into widespread use in terms of weight reduction and productivity. This tendency is especially strong in the automobile industry, which has been growing rapidly recently, and in the field of office equipment such as copying machines, typewriters, and computers.

In addition, in terms of function, these fields require use under extremely harsh conditions such as no lubrication and high speeds, so the sliding parts used in these fields, such as sliding bearings, slider gears, and cams, are of excellent quality. (2) In addition to sliding properties, high functionality such as high mechanical strength and heat distortion temperature is required. For example, sliding bearings are required to have characteristics such as a high limit PV value and excellent dimensional stability, while sliders, gears, cams, etc. are required to have characteristics such as excellent qualitative characteristics.

The limit PV value mentioned here is used as a guideline when plastic is applied to sliding bearings, etc., and the temperature rises significantly due to the generation of frictional heat at the sliding end surface, causing the plastic to soften and melt. , is the product of the pressure P applied to the bearing at the limit where it is no longer possible to continue normal frictional motion due to chemical decomposition, etc., and the sliding speed V.

Thermoplastic aromatic polyetherketone resin has the highest melting point among thermoplastic resins at 334°C and can be easily injection molded, so it contains a fluorocarbon polymer, preferably polytetrafluoroethylene. By imparting lubricity, we can expect to advance into the above-mentioned fields (3). Compositions containing fluorocarbon polymers have a heat deformation temperature of approximately 160°C; at temperatures higher than this, mechanical strength decreases significantly and dimensional stability deteriorates, making it difficult to use the compositions as sliding bearings. In this case, only a low limit pv value of about 400 to 2.m/min can be obtained, and the range of application is significantly limited. In addition, various sliders, gears,
Even when applied to a cam, it is difficult to use it in a high temperature atmosphere exceeding 150°C.

In view of the above problems, the inventors of the present invention have made extensive studies and found that
By further containing carbon fibers in a composition formed by containing a fluorocarbon polymer in a thermoplastic aromatic polyetherketone resin, the limit pv value,
The inventors have discovered that the mechanical strength and heat resistance (thermal distortion temperature) are significantly improved, and the range of application as sliding members such as oil-free bearings, sliders, gears, and cams is widened, leading to the present invention.

(4) The aromatic polyetherketone used in the present invention contains one repeating unit ÷oOcoQo- alone or together with other repeating units, and has an intrinsic viscosity of 0.7 to 2.6 or less, preferably is between 0.8 and 1.8. Other repeating units include -/C>0000- -Q-502. Although the polymer may contain less than 25% by weight of -Q-〇-, etc., a polymer containing 25% by weight or more is not preferred because the original properties of the polyetherketone are lost. Also, the intrinsic viscosity is the solution I Q Q c
Density 1.84 f/♂ with 0.12 polymer per m”
is the intrinsic viscosity measured for a polymer solution in concentrated sulfuric acid.

The intrinsic viscosity was measured using a viscosity needle with a solvent flow time of approximately 2 minutes. This intrinsic viscosity is (5) a value that uniquely corresponds to the molecular weight of the polymer.

Further, the polyetherketone having an intrinsic viscosity lower than 0.7 has low heat resistance, and even if a molded article is obtained, it is extremely brittle. On the other hand, if it exceeds 2.6, the melt viscosity is too high and the processability is poor, making it generally unusable.

Fluorocarbon polymers that can be used in the present invention include polytetrafluoroethylene, polytetrafluoroethylene-
It includes hexafluoropropylene copolymer, polytrichlorofluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc., and polytetrafluoroethylene (hereinafter abbreviated as PTFE) is particularly preferred. Also, among PTFE, lubricant-grade PTFE powder with an average particle size of less than 20μ is preferable, and examples of reprinted PTFE powders include Fluon ■169 and L170.
, L 171 (IC: made by I Handicraft), LeBron L-
Examples include 2, L-5, LD-1 (manufactured by Daikin Industries, Ltd.), Teflon ■TLP-IQ, and TLP-1OF-1 (manufactured by Devon Corporation).

(6) The carbon fibers that can be used in the present invention may be acrylonitrile-based, pitch-based, cellulose-based, etc., and preferably have a fiber length of 0.1 to 10 mm, but are not commonly used for resin filling. Chopped fibers or rovings with a length of about 1 mm are used. The surface of the carbon fiber is treated with various treatment agents, such as epoxy resin,
It is preferable to use a resin treated with polyamide resin, poly-11inate resin, polyacetal resin, etc., but the present invention is not limited thereto.

Examples of the carbon fibers include Magnamite AS, Magnamite HMS (manufactured by Vercules), and Trading Card T3.
00 A (manufactured by Toshisha Co., Ltd.), Best Fight HTA, Best Fight 1000 (manufactured by Toho Rayon Co., Ltd.), Credit Card M
, Credit Card C (manufactured by Kenbetsu Kagaku Kogyo Co., Ltd.), etc.

The blending amount is 95 to 30% by weight of thermoplastic aromatic polyetherketone resin, and 2.5 to 30% by weight of fluorocarbon polymer.
60% by weight, carbon fiber 2.5-60% by weight (total amount of fluorocarbon polymer and carbon fiber (7) fibers is 5-70% by weight of the total resin composition)
A combination is effective. That is, the total amount of fluorocarbon polymer and carbon fiber is 70% by weight of the resin composition.
If the amount of thermoplastic aromatic polyether ketone resin exceeds 30% by weight, mixing will be insufficient, a uniform composition will not be obtained, the fluidity of the resin composition will be lost, and molding will be difficult. It becomes difficult. Further, when the total amount of the fluorocarbon polymer and carbon fiber is less than 5% by weight, sufficient sliding properties and mechanical strength cannot be obtained. Furthermore, even if the total amount of fluorocarbon polymer and carbon fiber is 5 to 70% by weight, if the amount of fluorocarbon polymer is less than 2.5% by weight, the lubricity will be insufficient, and if it exceeds 60% by weight, the lubricity will be insufficient. , dispersibility and compatibility deteriorate, making it difficult to obtain a uniform composition.

On the other hand, if the amount of carbon fiber is less than 2.5% by weight, the limit PV
There is no effect of improving the value, and there is almost no improvement in mechanical strength or heat distortion temperature, and when the amount exceeds 60% by weight, the bulk density of the thermoplastic aromatic polyetherketone resin and carbon fiber (8) significantly increases. As a result, mixing becomes insufficient, the compounding process becomes difficult, and a uniform composition cannot be obtained.

To the resin composition of the present invention, a solid lubricant such as graphite or molybdenum disulfide is added to further improve lubricity, and a highly crystalline heat-resistant resin such as oxybenzoyl polyester is added to improve wear resistance. It is also possible.

As a mixing method for obtaining the resin composition of the present invention, a thermoplastic aromatic polyetherketone resin, a fluorocarbon polymer, and carbon fiber are tri-blended in a mixer such as a Henschel mixer or a super mixer, and then A common method is to melt-knead with a shaft extruder, extrude the strands, and pelletize with a cutter, but the method is not particularly limited to this method. Furthermore, sliding parts such as bearings and sliders can be easily obtained from the composition of the present invention by injection molding.

The resin composition according to the present invention has an extremely high limit PV value, mechanical strength, and heat distortion temperature compared to a composition consisting of a thermoplastic aromatic (9) group polyetherketone resin and a fluorocarbon polymer. It is a suitable molding material for sliding members such as bearings, sliders, cams, etc. that are used under harsh conditions.

The present invention will be explained by the following examples, but these are illustrative of preferred embodiments and are not intended to limit the scope of the present invention.

Examples 1 to 6 Thermoplastic aromatic poIJ-1- having the basic structural unit -C¥00co-1;Qo- and having an intrinsic viscosity of 1.4
-f Luquen,! : PTFE (Full-on L16
9, manufactured by ICI) and carbon fiber (Magnamai) 1800 A with a cross-sectional diameter of 7 to 9μ and an average fiber length of 6 mm.
S) were mixed in a Henschel mixer to the composition ratio shown in Table 1, and then mixed in a twin-screw extruder (PCM-
In ao), the temperature at the center of the cylinder was set at 340 to 360°C, and extrusion (10) was performed to obtain pellets. Using a 10Z injection molding machine (Neomat 47/2B manufactured by Sumitomo Heavy Industries), set the temperature at the center of the cylinder to 370 to 3909 C1.
) Measurement specimen (thickness 12.6 mm, width 6.4 mm, length 126 mm, ) and wear ring (outer diameter 25.6 mm)
mm, inner diameter 2Qmm, height 15mm).

Tensile properties, HDT, and critical pv value were measured from each test piece.

The limit pv value was measured using a water supply type abrasion tester (manufactured by Toyo Baldwin). Pressure ゛P = 10 to 9/
ar+", speed V = 4 Q m/min (under conditions D, the mating material is steel (845C), sliding is performed for 2 hours, then P is constant at 15 cm/cm", and ■ is PV= 500, 600, 700-...Q/cm"
m/min at a rate of 100 increments of 2 hours, and the sample undergoes abnormal wear accompanied by melting.
Sliding was continued until the pv value at which the coefficient of friction suddenly became unstable was reached, and the point at which this point occurred was defined as the limit pv value. These results are shown in Table 1.

As is clear from the table, all compositions have high tensile properties H
The DT limit pv value was shown.

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It was molded to have an outer diameter of 25 mm, an inner diameter of 20 ffIm, and a length of 29 mm), was attached to a copying machine, and was subjected to an actual machine test for 300 hours. The test was conducted by setting the roll surface temperature of the copying machine to 180 to 200°C. For all compositions, wear and dimensional changes were within an acceptable range after 300 hours.

Comparative Examples 1 to 4 Using exactly the same thermoplastic aromatic polyether ketone, fluorocarbon polymer, and carbon fiber as in Examples 1 to 6, similar studies were conducted on various blending ratios outside the effective range of these compositions. The results are shown in Table 2.

Both the system containing no carbon fiber (Comparative Example 1) and the system containing less than 2.5% by weight (Comparative Example 2),
Compared to the compositions of Examples 1 to 6, the tensile properties are greater in elongation, but the strength and elastic modulus are very low. Further, the HDT was 160 to 185°C, which was about half, and the limit PV value was also about h.

The system in which the amount of fluorocarbon polymer was less than 2.5% by weight (Comparative Example 3) had poor lubricity and a high coefficient of friction, so that only very low limit PV values were obtained. The total amount of fluorocarbon polymer and carbon fiber is 70% by weight.
The system exceeding the above (Comparative Example 4) was difficult to injection mold due to insufficient fluidity.

(15) In addition, the compositions of Comparative Examples 1 to 3 were subjected to actual machine tests as copying machine bearings in the same manner as in Example 3.5.
In Comparative Examples 1 and 2, the samples were significantly deformed after 5 and 10 hours of measurement, and in Comparative Example 3, a squeaking sound occurred after 10 hours, and the rotation became abnormal.

(17 completed)

Claims (1)

[Claims] Excellent sliding properties, high mechanical strength, containing 95 to 30% by weight of thermoplastic aromatic polyetherketone resin, 2.5 to 60% by weight of fluorocarbon polymer, and 2.5 to 60% by weight of carbon fiber; A resin composition having a heat distortion temperature.