JPS58160347A - Resin composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. suitable for use as a sliding material for oilless bearing, gear, cam, etc., by blending an arom. polyether ketone resin, a fluorocarbon polymer and an oxybenzoyl polyester 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% oxybenzoyl polyester such as Ekonol E-101 (a product of Sumitomo Kagaku Kogyo K. K.) are blended together.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition that provides a molded article with excellent sliding properties by blending an aromatic polyetherketone with a fluorocarbon polymer bottle and an oxybenzoyl polyester.

More specifically, the present invention relates to a resin composition that provides an oil-free bearing with excellent wear resistance and lubrication properties.

Aromatic polyetherketone resin is disclosed in Japanese Patent Application Laid-open No. 54-902.
It is known to have high heat resistance, flame resistance, mechanical, electrical properties, and chemical resistance, as described in 96 et al. (1) Taking advantage of their excellent properties, it has been suggested that they can be used as insulating coatings for electric wires and cables, but they are also used not only for coating electric wires and cables, but also for providing insulation coatings and corrosion resistance for various conductors. By expanding the scope of its use, development of various industries such as electrical and mechanical industries is expected. In addition, compositions containing aromatic polyetherketone and a fluorocarbon polymer, preferably polytetrafluoroethylene, have self-lubricating properties in addition to the above properties, making them suitable for various applications involving sliding. is expected to develop.

However, the sliding properties of a composition comprising an aromatic polyetherketone resin and a fluorocarbon polymer are insufficient for use in oil-free bearings and the like.

In general, in order to use plastics as sliding materials such as bearings, in addition to having a low and stable coefficient of friction,
Properties such as a high limit PV value and a low wear coefficient representing wear resistance are required.

(2) The pv value is the product of the pressure P applied to the bearing and the sliding speed. This is the limit pv value at which chemical decomposition occurs and normal frictional motion cannot continue. However, even under usage conditions within the limit pv value, wear always progresses little by little, so the life span must be taken into consideration.

For this reason, as a material for bearing design, the wear coefficient is more important than the limit PV value, and the limit PV value is used as a guideline for the usage limit of bearings, etc.

By the way, the wear coefficient is generally expressed by the following formula.

K=W/PVT [W: Wear 11 (mm), P: Pressure (K117
0m”), V: Speed (m/min), T
:Time (hr), :] Similar to the limit pv value, the value of K changes depending on the values of P and V even if the pv value used is the same. In other words, even at the same pv value, high pressure,
(3) It varies depending on low speed conditions, low pressure, and high speed conditions. However, in general, it is proportional to pressure and traveling distance (product of speed and time), so in the case of a K unit bearing, this value is l
It is said that if it is below Xl0', it can be used without any lubrication without any problem even considering the life factor.

However, a bearing obtained from a composition containing a fluorocarbon polymer in an aromatic polyetherketone resin was found to be within the limit pv value (approximately 400 Kg/cm2・m2) without lubrication.
/min) When using Te, the K value is 5X10'
~5X10'', 1 less than the required value
Since it is an order of magnitude larger, the bearing life is extremely short. Therefore, if the composition is further filled with a fibrous reinforcing material such as glass fiber or carbon fiber, the value may be slightly reduced, but this poses a problem of damaging the mating metal. This phenomenon is particularly noticeable when the mating metal is a soft metal such as aluminum or SUS, and once metal wear particles are generated,
This acts as a rough and abrasive effect on the plastic side (4), making the coefficient of friction unstable and accelerating wear on the plastic side. In addition, by further containing a solid lubricant such as graphite in the composition,
Since the lubricity is further improved and thermal conductivity is imparted, the K value is slightly improved, but it is not sufficient.

In order to improve the above-mentioned problems, the present inventors have made extensive studies and found that by further containing oxybenzoyl polyester in a composition comprising an aromatic polyetherketone resin and a fluorocarbon polymer, the wear coefficient can be improved. It was found that when used as a bearing with a value of , it can be used without problems even considering the life factor, and there is no damage to the mating material, leading to the present invention.

That is, 95-30% by weight of aromatic polyetherketone resin, 2.5-60% by weight of fluorocarbon polymer, and 2.5-60% by weight of oxybenzoyl polyester.
It was found that the above-mentioned problems could be solved by creating a composition of the following, leading to the present invention (5).

The aromatic polyetherketone used in the present invention contains the repeating unit -Q-O-Q-CO+〇- alone or together with other repeating units, and has an intrinsic viscosity of 0.7 to 2.6 or less. , preferably from 0.8 to 1.8. Other repeating units may include less than 25% by weight of (yco÷〇- 00÷502÷〇- -JC>SO2÷〇-), but polymers containing 25% by weight or more are properties are lost, which is undesirable.In addition, the intrinsic viscosity is 1.84 L!I/ctm containing 0.12 polymer per 100 Ci of solution.
3 is the intrinsic viscosity measured for a polymer solution in concentrated sulfuric acid.

The intrinsic viscosity was measured using a viscometer with a solvent flow time of approximately 2 minutes (6). This intrinsic viscosity is 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 is extremely brittle even if a molded article is obtained. 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., but especially polytetrafluoroethylene (hereinafter abbreviated as PTFE).
is preferred. Also, among PTFE, the average particle size is 20
Lubricant grade PTFE powder of less than μ is preferred, and commercially available examples include Sakai Luon 169, L
170, L 171 (manufactured by ICI Miki), LeBron ■L-2, L-5, LD-1 (manufactured by Daikin Industries), Teflon ■TLP-IQ, TLP-(7) 10F-1 (manufactured by DuPont), etc. There is.

The oxybenzoyl polyester that can be used in the present invention is
Generally, it has a repeating unit of the following formula σV), and it hardly softens at temperatures below 400°C and has excellent wear resistance, compression creep resistance, and chemical resistance. In addition, its crystal structure is similar to solid lubricants such as graphite and molybdenum disulfide, and it has plate-shaped crystals, so it has excellent self-lubricating properties.
It is used as a wear resistance improving material for E.

For example, when PTFE contains 20% by weight of oxybenzoyl polyester, the amount of wear is lower than that of PTFE.
The coefficient of friction is approximately 1/1000 or less of that of PTFE, which not only maintains the low value of PTFE, but also provides an excellent sliding material that is stable and does not damage the mating material.

(8) The method for synthesizing this oxybenzoyl polyester is as follows:
A method using a high boiling point solvent as a polymerization medium as used in Japanese Patent Publication No. 46-6796 and Japanese Patent Publication No. 47-47870, Japanese Patent Publication No. 54-46287, and Japanese Patent Publication No. 54-462
There is a bulk polymerization method that does not substantially use a solvent in the polymerization system, as shown in 91.
1 (manufactured by Sumitomo Chemical Industries).

The blending amount is aromatic polyetherketone 95-30
% by weight, fluorocarbon polymer 2.5-60% by weight,
A blend of 2.5 to 60% by weight of oxybenzoyl polyester (the total amount of fluorocarbon polymer and oxybenzoyl polyester is 5 to 70% by weight of the total resin composition) is effective.

That is, when the total amount of the fluorocarbon polymer and oxybenzoyl polyester exceeds 70% by weight of the resin composition and the amount of the aromatic polyetherketone is less than 30% by weight, the resin composition loses its fluidity. Even if a molded article (9) could be obtained by injection molding, it would have very low mechanical strength and be brittle. Furthermore, when the total amount of the fluorocarbon polymer and oxybenzoyl polyester is less than 5% by weight, sufficient sliding properties cannot be obtained.

Furthermore, even if the total amount of fluorocarbon polymer and oxybenzoyl polyester is 5 to 70% by weight, if the amount of fluorocarbon 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 oxybenzoyl polyester is less than 2.5% by weight, the abrasion resistance is insufficient, and as the amount increases, the improvement in abrasion resistance becomes more remarkable, but if it exceeds 60% by weight, the fluidity of the composition There is a significant decrease in the strength of the resulting molded product.

It is also possible to add a solid lubricant such as graphite or molybdenum disulfide to the resin composition of the present invention in order to further improve the lubricity.

The mixing method (10) for obtaining the resin composition of the present invention includes tri-blending aromatic borie-thylketone, fluorocarbon polymer, and oxybenzoyl polyester using a mixer such as a Henschel mixer or a super mixer. After that, a common method is to melt-knead the mixture using a -screw or multi-screw extruder, extrude the strands, and pelletize them using a cutter, but the method is not particularly limited thereto. Furthermore, injection molding is generally applied to obtain molded products such as bearings from the composition of the present invention.

The resin composition according to the present invention has excellent sliding properties,
The wear coefficient, which is one of the data for bearing design, is more than an order of magnitude lower than that of the composition consisting of aromatic polyetherketone and fluorocarbon polymer (IX□.-5 to IOX□.-52). /summer), Km Cm2 It is a molding material suitable for use as an oil-free bearing.

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 Aromatic polyetherketone and PTFE having the basic structural unit -Q-O÷COTYO- and having an intrinsic viscosity of 1°4
(Fluon L 196.

ICI) and oxybenzoyl polyester (Econol ■E 101, manufactured by Sumitomo Chemical Industries, Ltd.) having an average particle size of about 20μ were mixed in a Henschel mixer at the composition ratio shown in Table 1, and then mixed in a twin-screw extruder. (PCM-30 made by Tamami Tekko) to set the temperature at the center of the cylinder to 340~
The temperature was set at 360°C, and extrusion granulation was performed to obtain pellets. Using a 10Z injection molding machine (Neomat 47/28 manufactured by Sumitomo Heavy Industries), the temperature at the center of the cylinder was adjusted to 3.
Set the temperature to 60 to 380°C, and use JIS No. 1 dumbbells and wear rings (outer diameter 25.6 mm, inner diameter 20 mm,
15 mm in height). The tensile properties of JIS No. 1 dumbbells were measured, and the wear rings were measured using a precious wood type abrasion tester at a pressure of P-10 Kf/cm2 and a speed of 20 m/cm.
The mating material was SUS 3Q4 under the minimum condition, and after 2 hours of break-in operation, 20 hours of sliding was performed to determine the friction coefficient, wear coefficient, wear amount of the mating material, amount of polyester added, tensile strength, Although the elongation decreased somewhat, the decrease in the wear coefficient, which indicates wear resistance, was significant, and the friction coefficient was low and stable under the chair, compared to the mating material SUS 3.
Almost no wear was observed on 04.

(13) Also, using the composition of Example 3.5, a bearing with an outer diameter of 15 mm, an inner diameter of 6 □m, and a length of 10 rnm was molded by injection molding, and P11'' = 10 Kg/cn using a small bearing testing machine. '', speed 20 m/min (y) Conditions S SUS 304 was used as the mating shaft, and sliding was performed for an initial period of 2 hours, 50 hours, 100 hours, and 300 hours, and the wear coefficient was determined from the amount of wear. These results are the second
Shown in the table.

As is clear from the table, for both compositions, the initial 2h
Although the wear coefficient of r was slightly high, the wear coefficient decreased with time, and no abnormality was observed even when an aoo hr test was performed.

(14) Comparative Examples 1 to 4 Using exactly the same aromatic polyether ketone, fluorocarbon polymer, and oxybenzoyl polyester as in Examples 1 to 7, similar studies were conducted on various blending ratios outside the effective range of these compositions. The results are shown in Table 3.

Both the system containing no oxybenzoyl polyester (Comparative Example 1) and the system containing less than 2.5% by weight (Comparative Example 2) have insufficient abrasion resistance, and the amount of fluorocarbon polymer is 2.5% by weight. % (Comparative Example 3) has a high coefficient of friction and a high coefficient of wear. Furthermore, a system in which the total amount of fluorocarbon polymer and oxybenzoyl polyester exceeded 70% by weight (Comparative Example 4) was difficult to injection mold due to insufficient fluidity.

Claims (1)

[Claims] A resin composition with excellent sliding properties containing 95-30% by weight of aromatic polyetherketone, 2.5-60% by weight of fluorocarbon polymer and 2.5-60% by weight of oxybenzoyl polyester.