JPH07331011A - Sliding composition - Google Patents

Abstract

PURPOSE:To obtain a sliding composition small in abrasion coefficient, excellent in mechanical strength and sealability, and useful for piston rings, etc., by compounding a specific base resin, a lubricating filler such as carbon, and an abrasion-resistant filler such as potassium titanate in a specific ratio. CONSTITUTION:This sliding composition is produced by compounding (A) 50-85wt.% of ethylene tetrafluoride resin and 5-50wt.% of a polyethersulfone, and further compounding (B) 2-15wt.% of a lubricating filler comprising one or more kinds of carbon, graphite and molybdenum disulfide and (C) either one kind of potassium titanate, wollastonite, zonotolite and aramid fibers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slidable composition which is used in parts such as piston rings, rod packings, bearings, etc., which require slidability and wear resistance.

[0002]

2. Description of the Related Art Conventionally, as a slidable composition used for a portion such as the above example, for example, tetrafluoroethylene resin serving as a base resin, heat resistance of wholly aromatic polyester, polyimide, polyphenylene sulfide, etc. There is a composition in which a resin is blended in an appropriate amount, and further, a filler such as glass fiber, carbon fiber, calcium carbonate, talc, glass powder, copper, mica is blended in an appropriate amount.

[0003]

However, the composition to which the above-mentioned filler is added has a large coefficient of friction and a large coefficient of wear as shown in Table 2. In addition, it has the characteristics that it easily damages the mating material and is highly aggressive. When the composition is used in an appropriate portion, the amount of wear generated in the mating material is large and damage or breakage may occur, so that it is not possible to secure good sealing properties for a long period of time. In addition, as shown in FIG. 3, when the PV value becomes high, the wear coefficient of the composition rapidly increases, and there is a problem that abnormal wear occurs in the composition and the mating material.

Further, since the composition and the mating material are worn out in a short period of time, it is necessary to replace them regularly. For example, a composition using polyether ketone (PEK) (Japanese Patent Laid-Open No. 212539/1990). ) Is more expensive than the composition of the present invention using polyether sulfone (PES), and the price when commercialized is about 4 times to about 5 times, so it is inevitable that the replacement time becomes short. In addition, the number of times of replacement increases, which causes a problem of cost increase.

In view of the above problems, the present invention comprises blending a tetrafluoroethylene resin and polyether sulfone in a base resin of a composition, and blending a lubricating filler and an abrasion resistant filler in the base resin. As a result, the wear resistance and the mechanical strength are remarkably improved, excellent sealing properties can be obtained for a long period of time, and the number of replacements can be reduced to reduce the cost. For the purpose of provision.

[0006]

The slidable composition of the present invention comprises a tetrafluoroethylene resin as a base resin constituting the composition in an amount of 50 wt% to 85 wt% and a polyether sulfone in an amount of 5 wt% to 50 wt%. As a lubricating filler to be filled in the base resin, one or more of carbon, graphite and molybdenum disulfide are blended in an amount of 2 wt% to 15 wt% and the wear resistance filled in the base resin is It is characterized in that it is a slidable composition containing 5 wt% to 30 wt% of any one of potassium titanate, wallostite, xonotlite and aramid fiber as a filler.

[0007]

According to the present invention, tetrafluoroethylene resin and polyether sulfone are blended as the base resin of the composition, and one or more of carbon, graphite and molybdenum disulfide are blended as the lubricating filler. However, since one kind of potassium titanate, wallostite, xonotlite, and aramid fiber is blended as the wear-resistant filler, as shown in Table 2, as compared with the composition of the conventional example, the composition that constitutes the present invention. Since the product has a smaller friction coefficient and wear coefficient and more stable slidability, wear resistance and mechanical strength are remarkably improved, and excellent sealability can be obtained for a long period of time. Moreover, since the damage to the mating material is small and the wear resistance is excellent, the life is greatly extended, the number of times of replacement can be reduced, and the cost can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The drawing shows a slidable composition used in a portion where slidability and wear resistance are required.
An appropriate amount of a lubricating filler and an abrasion resistant filler is mixed with the base resin constituting the composition, and the composition is molded. That is, an appropriate amount of tetrafluoroethylene resin (PTFE) and polyether sulfone (PES) are blended as a base resin, and carbon powder (C), graphite (Gr), as a lubricating filler filled in the base resin, Molybdenum disulfide (M
oS2) is appropriately mixed in an appropriate amount, and as a wear-resistant filler to be filled in the base resin, plate-like potassium titanate (PTW), wallstone (WW) is used.
n), xonotlite, and aramid fiber (Af) are mixed in an appropriate amount, and the composition is formed into an appropriate shape by a free baking forming method (preliminary forming and firing in an electric furnace) described later.

When molding the above-mentioned slidable composition, for example, a tetrafluoroethylene resin is used as a base resin in an amount of 50.
wt% -85wt% blended, polyethersulfone 5wt%
In addition to 50 wt%, 2 wt% to 15 wt% of carbon powder, graphite, or molybdenum disulfide is added as a lubricating filler, and plate-like potassium titanate (diameter is used as a wear-resistant filler). = 10μ-30
μ, length = 80μ to 350μ), 5 wt% to 30% of any one of Wallacenite, zonotolite and aramid fiber
After blending wt%, the composition raw materials are dry blended (dry mixed). The composition raw material is compression-molded into an appropriate shape and dimension by a free-baking forming method (preliminary forming and then fired in an electric furnace), followed by firing treatment, and then cutting into an appropriate shape and dimension.

The above-mentioned tetrafluoroethylene resin is 50 wt.
% To 85 wt%, but if the blending amount is reduced to 50 wt% or less, the elongation (elasticity) of the composition becomes small and the moldability deteriorates. On the other hand, if the compounding amount is increased to 85 wt% or more, sufficient wear characteristics cannot be obtained and the durability required for long-term use cannot be obtained. In addition, since cold flow resistance is significantly reduced, it is preferably 60 wt% to 80 wt%.
It is most suitable to use in the compounding range of.

Polyethersulfone is 5 wt% to 50 wt%
%, But if the compounding amount is reduced to 5 wt% or less, sufficient wear characteristics cannot be obtained, and there is no improvement effect by the addition. On the other hand, if the compounding amount is increased to 50 wt% or more, the formability is deteriorated and problems occur in cutting and manufacturing. Therefore, it is optimal to use the compounding range of 10 wt% to 30 wt%.

The carbon powder, graphite and molybdenum disulfide used as the lubricating filler are 2 wt% to 15%.
It is optimal to use it in the blending range of wt%. If the compounding amount is reduced to 2 wt% or less, the effect of addition (reduction of wear coefficient, suppression of heat generation temperature, improvement of wear performance) does not appear remarkably. On the other hand, if the compounding amount is increased to 15 wt% or more, the dispersibility decreases, deformation and distortion occur, and the moldability deteriorates. In addition, the filler compounded in the molded product may fall off or peel off.

The plate-like potassium titanate, wallestonite, xonotlite and aramid fiber used as the wear resistant filler are optimally used in the range of 5 wt% to 30 wt%. If the compounding amount is reduced to 5 wt% or less, the strengthening effect in strength does not appear, and the improvement of wear characteristics deteriorates. On the other hand, if the compounding amount is increased to 30 wt% or more, the dispersibility of the filler decreases and deformation or distortion occurs, resulting in poor moldability. Moreover, since the filler compounded in the molded product may fall off or peel off, a good molded product cannot be obtained.

Further, by adding potassium titanate, wallestonite and zonolite after surface-treating them with a titanate coupling agent or a silane coupling agent, the adhesion between these fillers and polyether sulfone is improved. The entanglement of the molecular chains of the tetrafluoroethylene resin and the polyethersulfone suppresses the slippage of potassium titanate, wallestonite, and zonolite, and improves the mechanical strength and cold flow resistance.

FIGS. 1 and 2 show a method for testing a slidable composition 1 by means of a Suzuki type friction and wear thrust tester 2, which thrust tester 2 slides on the upper surface side of a rotary table 3 which constitutes the same. Of the mating material 4 is fixed, the mating material 4 made of metal is pressed against the upper surface of the slidable composition 1, and then the mating material 4 is pressed while rotating the turntable 3 to slide the mating material 4. The exothermic temperature generated in the part and the coefficient of friction are measured.

That is, when measuring the exothermic temperature, the thermocouple 5 is inserted at a position about 3 mm away from the sliding portion of the mating member 4, and the thermoelectromotive force generated at the connection point of the thermocouple 5 is converted into the exothermic temperature. Record with a pen recorder (not shown). Moreover, when measuring the friction coefficient, the friction resistance during sliding is detected by a load cell (not shown), and the resistance value is recorded by a pen recorder.

As a comparative example of the above-mentioned sliding composition 1,
For example, tetrafluoroethylene resin (PTFE), polyether sulfone (PES), carbon powder (C), graphite (Gr), molybdenum disulfide (MoS2), plate-like potassium titanate (PTW), wallestnite (W).
n), xonotlite, and aramid fiber (Af) are mixed in appropriate amounts. Each test piece A, B, C, D, E, F of the present invention,
G, H, I and tetrafluoroethylene resin (PTFE), wholly aromatic polyester (LCP), polyphenylene sulfide (PPS), glass fiber (GF), graphite (Gr), molybdenum disulfide (MoS2) in appropriate amounts. Each of the conventional test pieces J, K, L, and M prepared by blending is tested under the same test conditions by the above-mentioned Suzuki type friction and wear thrust tester 2.

Table 1 below shows the test pieces A to I of the present invention.
And the amount of each conventional test piece J to M mixed.

[0019]

[Table 1]

When the above-mentioned test pieces A to M are tested under the same conditions, the test temperature in air is room temperature (about 25
℃), the mating material is set to S45C, the test time is set to initial sliding 0Hr to 4Hr, and normal sliding 4Hr to 20Hr
And the test surface pressure P, the test speed V, and the PV value are set to the test conditions described later, and each of the test pieces A to M is tested.

As a first test condition, a test surface pressure P of 0.
29MPa.m / sec (3kgf / cm ² ), test speed V 1m / sec (100cm / sec), PV value 0.29
Set to MPa.m / sec (300 kgf / cm ² · cm / sec). As the second test condition, the test surface pressure P is 0.59 MPa.m / sec
(6 kgf / cm ² ) and the test speed V is 1 m / sec (10
0cm / sec) and PV value is 0.59MPa.m / sec (6
00kgf / cm ² · cm / sec).

As the third test condition, the test surface pressure P is 0.
Set to 98MPa.m / sec (10kgf / cm ² ) and test speed V
Is set to 1 m / sec (100 cm / sec) and PV value is set to 0.9
Set to 8MPa.m / sec (1000kgf / cm ² · cm / sec). Table 2 below shows the test pieces A to I of the present invention under the above conditions.
And the test results of the conventional test pieces J to M are shown.

[0023]

[Table 2]

When measuring the wear coefficient K described in Table 2 above, each test piece A was measured before the start of the test and after the end of the test.
The weights up to M are weighed with an analytical balance, and the wear height W is calculated from the wear weight M by the following formula 1.

[0025]

[Equation 1]

Further, the wear coefficient K is calculated from the wear height W, the test surface pressure P, the test speed V, and the test time H obtained here.
Is calculated by the following formula 2.

[0027]

[Equation 2]

As is clear from the above test results, there is no significant difference in the friction coefficient between the test pieces A to I of the present invention and the test pieces J to M of the conventional product. As shown, as compared with the conventional test pieces J to M, the test pieces A to I of the present invention have a smaller wear coefficient and the higher the PV value, the test pieces A to I of the present invention and the conventional test pieces A to I. Since the difference between each of the test pieces J to M of the product becomes large, it is proved that the wear resistance is excellent. Moreover, since the wear coefficient is stable, the mechanical strength is also excellent.

As described above, tetrafluoroethylene resin and polyether sulfone are appropriately mixed as the base resin constituting the slidable composition 1, and carbon powder is used as the lubricating filler to be filled in the base resin. , Graphite, and molybdenum disulfide are mixed in appropriate amounts, and as the wear-resistant filler, potassium titanate, wallestonite, zonotolite, and aramid fiber are appropriately mixed in appropriate amounts. In comparison with the conventional test pieces J to M, each of the test pieces A to I of the present invention has a smaller friction coefficient and wear coefficient and more stable slidability. The mechanical strength is remarkably improved, and excellent sealability can be obtained for a long period of time. Moreover, since the damage to the mating member 4 is small and the wear resistance is excellent, the life can be greatly extended, the number of replacements can be reduced, and the cost can be reduced.

The present invention is not limited to the configuration of the above embodiment. The above-mentioned tetrafluoroethylene resin, polyether sulfone, carbon powder, graphite, molybdenum disulfide, plate-like potassium titanate,
Walletite, xonotlite, and aramid fiber are compounded in an increasing amount and a decreasing amount within a preset range, and the above-mentioned slidable composition 1 is molded by increasing or decreasing each compounding amount according to the purpose of use and use conditions. Good.

[Brief description of drawings]

FIG. 1 is a perspective view showing a test shape of a slidable composition.

FIG. 2 is a side view showing a method for testing a slidable composition by a Suzuki type friction and wear thrust tester.

FIG. 3 is a characteristic diagram showing a relationship between a PV value of a test piece and a wear coefficient.

[Explanation of symbols]

 1 ... Sliding composition 2 ... Thrust tester 3 ... Rotating table 4 ... Counterpart material 5 ... Thermocouple

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C08K 7/02 KJN C08L 81/06 LRF F16C 33/24 A 7123-3J F16J 9/28

Claims (1)

[Claims] 1. A base resin constituting a composition, which is blended with 50 wt% to 85 wt% of tetrafluoroethylene resin and 5 wt% to 50 wt% of polyether sulfone, and which is a lubricating filler to be filled in the base resin. 2 wt% to 15 wt% of carbon, graphite, or molybdenum disulfide is blended as a material, and potassium titanate, wallestonite, xonotlite, aramid is used as an abrasion resistant filler to be filled in the base resin. A slidable composition containing 5 wt% to 30 wt% of any one of the fibers.