WO2019097791A1 - Sliding member and method for manufacturing same - Google Patents

Abstract

Provided is a sliding member wherein a sliding layer is capable of exhibiting excellent sliding properties in terms of seizure resistance, wear resistance, and heat resistance. This method is for manufacturing the sliding member that slides against an opposing member and involves: a crosslinking step of irradiating ultra-high-molecular-weight polyethylene in particulate form under sealed conditions to crosslink the ultra-high-molecular-weight polyethylene; a composition preparation step of preparing a sliding layer composition that contains a solid lubricant and a binder resin; and a sliding layer forming step of forming the sliding layer that slides against the opposing member by providing the sliding layer composition on a base material. The solid lubricant includes the ultra-high-molecular-weight polyethylene crosslinked in the crosslinking step.

Description

Sliding member and method of manufacturing the same

The present invention relates to a sliding member and a method of manufacturing the same.

Conventionally, sliding members disclosed in Patent Literatures 1 and 2 are known. These sliding members include a base material made of steel or aluminum and a sliding layer formed on the base material. An underlayer may be provided between the base material and the sliding layer. The sliding layer contains a binder resin and a solid lubricant. The binder resin is made of epoxy resin or the like. The solid lubricant of Patent Document 1 is composed of particulate molybdenum disulfide (MoS ₂ ), particulate polytetrafluoroethylene (PTFE), and particulate polyethylene. In recent years, ultrahigh molecular weight polyethylene has been studied from the characteristics of self-lubricity and wear resistance, and the solid lubricant of Patent Document 2 contains particulate crosslinked ultrahigh molecular weight polyethylene.

These sliding members may be employed as a propeller shaft, a piston or the like in which the sliding layer slides with the mating member. In particular, in the sliding layer of Patent Document 1, polyethylene having a good affinity to the lubricant is contained as a solid lubricant, and therefore, it is intended to realize a low coefficient of friction and high wear resistance. Further, in the sliding layer of Patent Document 2, crosslinked ultrahigh molecular weight polyethylene is used as a solid lubricant, and in addition to seizure resistance and abrasion resistance, high heat resistance is to be realized.

JP, 2013-189569, A JP, 2016-69508, A

However, in order to ensure the reliability of the sliding member, further improvement of the sliding characteristics is desired. In this respect, according to the test results of the inventors, even if crosslinked ultrahigh molecular weight polyethylene is employed as part of a solid lubricant, crosslinked ultrahigh molecular weight polyethylene is merely simply irradiated with radiation. If this is the case, the sliding layer can not necessarily exhibit high heat resistance. In some cases, the crosslinked ultrahigh molecular weight polyethylene becomes brittle and the lubricating properties of the sliding layer deteriorate.

The present invention has been made in view of the above-mentioned conventional situation, and provides a sliding member capable of exhibiting sliding characteristics excellent in seizure resistance, abrasion resistance and heat resistance in the sliding layer. The problem is to be solved.

The method for manufacturing a sliding member according to the present invention is a method for manufacturing a sliding member for manufacturing a sliding member that slides on a mating member,
Irradiating the particulate ultra high molecular weight polyethylene in a closed state with radiation to crosslink the ultra high molecular weight polyethylene;
A composition preparation step of preparing a composition for a sliding layer containing a solid lubricant containing the ultra-high molecular weight polyethylene crosslinked in the crosslinking step, and a binder resin;
And a sliding layer forming step of providing the sliding layer composition on a base material to form a sliding layer sliding on the other member, and obtaining a sliding member.

According to the test results of the inventors, in the sliding member obtained by the manufacturing method of the present invention, it is possible to improve the seizure resistance and the abrasion resistance which are superior to the appropriately crosslinked ultrahigh molecular weight polyethylene. The reason for this is that in the production method of the present invention, the ultra-high molecular weight polyethylene is irradiated with radiation in a sealed state in the crosslinking step, so the ultra-high molecular weight polyethylene is not easily oxidized and is appropriately crosslinked It is guessed that it is from. When the particulate ultra-high molecular weight polyethylene is irradiated with radiation in the open state, the ultra-high molecular weight polyethylene is oxidized and the ultra-high molecular weight polyethylene is less likely to be crosslinked.

According to the test results of the inventors, the crosslinking step is preferably performed under the condition that the absorbed dose of electron beam as radiation is 60 kGy or more and less than 500 kGy. Electron beams are convenient for handling. When the electron beam is irradiated with the absorbed dose in this range, the ultrahigh molecular weight polyethylene is appropriately crosslinked, and the sliding layer exhibits excellent heat resistance and abrasion resistance. When the cross-linking step is performed when the absorbed dose of the electron beam is less than 60 kGy, the cross-linking of the ultra high molecular weight polyethylene is insufficient and the abrasion resistance of the sliding layer is not sufficient. When the crosslinking step is performed when the absorbed dose of the electron beam is 500 kGy or more, the crosslinked ultrahigh molecular weight polyethylene becomes brittle and the abrasion resistance of the sliding layer is deteriorated.

The sliding member according to the present invention comprises a base material and a sliding layer formed on the base material and containing a binder resin and a solid lubricant, wherein the sliding layer slides on a mating material A member,
The solid lubricant is characterized in that it comprises a crosslinked ultra-high molecular weight polyethylene in particulate form and having a melting point of more than 126.4 ° C. and 132.0 ° C. or less.

According to the test results of the inventors, if the melting point of the ultra high molecular weight polyethylene is within this range, the friction coefficient of the sliding layer is low, the amount of wear is small, and the ultra high molecular weight from the surface of the sliding layer at high temperature It is difficult for polyethylene to leach out and fall off. It is presumed that the reason is that the ultrahigh molecular weight polyethylene is appropriately crosslinked. Therefore, the sliding layer can improve the seizure resistance and the abrasion resistance.

According to the test results of the inventors, the ultrahigh molecular weight polyethylene preferably has a gel fraction of 26% or more. In this case, the friction coefficient of the sliding layer is low, the amount of wear is small, and it is difficult for the ultrahigh molecular weight polyethylene to be eluted from the surface of the sliding layer at high temperatures. The ultrahigh molecular weight polyethylene having a gel fraction in this range is presumed to be suitably crosslinked.

According to the test results of the inventors, in the sliding layer, the solid lubricant is preferably 25% by volume or more and 100% by volume or less with respect to the binder resin. In this case, the binder resin can hold the fixed lubricant more. Further, in the sliding layer, the binder resin is preferably polyamideimide. Furthermore, it is preferable that the ultrahigh molecular weight polyethylene is 5% by volume or more and 35% by volume or less with respect to the total solid component in the sliding layer. In this case, the sliding layer can further improve the wear resistance under dry environment or under oil environment.

According to the inventors' test results, the solid lubricant preferably further contains molybdenum disulfide. Moreover, as for a sliding layer, it is preferable that a molybdenum disulfide is 26 volume% or less with respect to the total solid component in a sliding layer. In this case, the sliding layer can improve the abrasion resistance in a dry environment or in an oil environment.

According to the test results of the inventors, in the sliding layer, the ultrahigh molecular weight polyethylene is 23% by volume or more and 35% by volume or less with respect to the total solid component in the sliding layer It is preferable that it is 15 volume% or less with respect to all the solid components. In this case, the sliding layer can further improve the wear resistance, particularly in a dry environment.

According to the inventors' test results, the solid lubricant preferably further contains graphite. In the sliding layer, it is preferable that the graphite be 5% by volume or more and 30% by volume or less with respect to the total solid component in the sliding layer. In this case, the sliding layer can further improve the wear resistance under dry environment or under oil environment.

According to the manufacturing method of the present invention, it is possible to manufacture a sliding member in which the sliding layer can exhibit excellent sliding characteristics in terms of seizure resistance, abrasion resistance and heat resistance. Further, according to the sliding member of the present invention, the sliding layer can exhibit excellent sliding characteristics in terms of self-lubricity, wear resistance and heat resistance.

FIG. 1 is a schematic perspective view showing a pin-on-disk reciprocation test in Test 1. As shown in FIG. FIG. 2 is a cross-sectional view showing the swash plate × shoe test in Test 2. FIG. 3 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 1. FIG. 4 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 2. 5 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 3. FIG. FIG. 6 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 4. FIG. 7 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Comparative Example 2. FIG. 8 is a 500 × SEM image photograph of the sliding layer of Test 1 in the sliding member of Comparative Example 3. FIG. 9 is a schematic perspective view showing the ring-on-disk friction and wear test in Test 4. FIG. 10 is a schematic perspective view showing the pin-on-disk friction and wear test in Test 5.

<Crosslinking step>
As means for irradiating radiation in a sealed state to particulate ultrahigh molecular weight polyethylene, (1) a vacuum method of evacuating the inside of a container containing particulate ultrahigh molecular weight polyethylene to reduce the proportion of air; (2) A gas purge method or the like may be employed in which the inside of the container is filled with an inert gas or nitrogen and the air is discharged. As long as it is sealed, an atmosphere containing some oxygen may be used without using a vacuum method or a gas purge method.

As the radiation, other than alpha rays, beta rays, gamma rays, X-rays, electron beams, ion beams can be adopted. The amount of radiation is expressed as a dose that is proportional to the energy absorbed by the unit mass. Gray (Gy) is a unit that represents the amount of energy absorbed by a substance (referred to as absorbed dose) when it strikes a substance.

<Composition preparation process>
(Binder resin)
Binder resin is the retention of solid lubricant which makes it hard to separate solid lubricant, durability against shear force acting repeatedly under layered film (hardness as base), abrasion resistance which is hard to break, heat resistance etc. Demonstrate. A polyimide resin, an epoxy resin, a phenol resin etc. are employable as binder resin. Polyamide imide (PAI), a polyimide, etc. are employable as a polyimide-type resin. It is optimal to use PAI as the binder resin in consideration of cost and characteristics.

(Solid lubricant)
The solid lubricant is held by the binder resin, and exerts a low shear force and a low coefficient of friction at the outermost surface. As the solid lubricant, fluorine resin, molybdenum dioxide, graphite, ultrahigh molecular weight polyethylene and the like can be adopted. The fluorine resin and the ultrahigh molecular weight polyethylene form a film on the sliding surface of the sliding layer, and improve the sliding property by transferring to a mating material. Molybdenum dioxide and graphite improve slipperiness due to the low shear crystal structure and achieve low friction at high loads. According to the test results of the inventors, although the fluorocarbon resin has sliding properties such as abrasion resistance and seizure resistance, it has oil repellent properties, and the contact angle of the lubricating oil is relatively high. large. On the other hand, although ultrahigh molecular weight polyethylene is inferior to fluorocarbon resin in sliding characteristics, it has lipophilic properties and the contact angle of lubricating oil is relatively small. Further, as the solid lubricant, soft metals such as melamine cyanurate (MCA), calcium fluoride, copper and tin can be adopted. In particular, ultra-high-molecular-weight polyethylene which is appropriately crosslinked can not be easily eluted from the surface of the sliding layer at high temperatures, and can improve excellent seizure resistance and abrasion resistance.

The ultrahigh molecular weight polyethylene before crosslinking preferably has an average molecular weight of 1,000,000 to 7,000,000. The specific gravity of the ultrahigh molecular weight polyethylene before crosslinking is preferably 0.92 to 0.96. The ultrahigh molecular weight polyethylene before crosslinking preferably has a particle diameter of 30 μm or less, more preferably 15 μm or less, from the viewpoint of surface smoothness and abrasion resistance.

(Additives, etc.)
The sliding layer may have additives in addition to the binder resin and the solid lubricant. As the additive, those capable of improving the hardness of the sliding layer, such as hard particles such as titanium dioxide, tribasic calcium phosphate, alumina, silica, silicon carbide and silicon nitride, can be employed.

The sliding layer may contain a sulfur-containing metal compound such as ZnS or Ag ₂ S as an extreme pressure agent. The sliding layer may also have a surfactant, a coupling agent, a processing stabilizer, an antioxidant, and the like.

As a silane coupling agent used for a silane coupling process, it is preferable that a functional group is an epoxy group. 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glydoxysilane as a silane coupling agent having an epoxy group as a functional group Preferred is cidoxypropyltriethoxysilane. These are also excellent in storage stability.

<Sliding layer formation process>
In the sliding layer forming step, sliding with a solvent such as n-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, or xylene is optionally performed depending on the type of coating method such as spray coating or roll coating. It is possible to dilute the layer composition and to adjust the viscosity and solid concentration. After the base material is coated with the diluted material for the sliding layer composition, drying and baking can be performed to form the sliding layer.

(First experiment)
Hereinafter, Examples 1 to 4 and Comparative Examples 1 to 3 in which the present invention is embodied will be described. First, the following materials were prepared.
Binder resin: Polyamideimide resin (PAI) varnish Solid lubricant: Particulate ultra high molecular weight polyethylene (UHPE particles), particulate fluorine compound (PTFE particles), MoS ₂ , graphite

A plurality of vinyl bags of the same size, which can be air-tight, were prepared, and UHPE particles were put in a fixed amount, and the inside of each bag was vacuumed under the same conditions. Thereafter, each bag was placed in an electron beam irradiation apparatus, and the UHPE particles were irradiated with an electron beam as radiation at the absorbed dose (kGy) shown in Table 1. Thus, the crosslinked product No. One to four UHPE particles were obtained. The uncrosslinked UHPE particles were those which were not irradiated with the electron beam. The UHPE particles in the non-hermetically crosslinked product are in an open air state, that is, those irradiated with an electron beam without being put in a bag.

Table 1 shows the melting point (° C.), gel fraction (%) and average particle size (μm) of each UHPE particle. Further, the melting point (° C.) and the average particle size (μm) of the PTFE particles are also shown in Table 1.

Here, the measurement conditions of the melting point are as follows.
Analyzer: DSC Q2000 (TA instrument)
Temperature rising rate: 5 ° C./minute (After raising the temperature to 210 ° C., it was cooled to 30 ° C. at −20 ° C./minute, and measurement was performed again.)
Atmosphere: N ₂
Sample weight: 5 mg ± 0.1 mg each
Melting point reading conditions: peak temperature of melting at another measurement

The gel fraction was measured as follows. First, each powder was formed into a 0.3 mm-thick sheet by pressurizing each powder at a constant pressure while heating at 180 ° C. to 230 ° C. A 0.3 g piece was cut from each sheet. Each piece was placed in a flask and 500 ml of p-xylene was added to the flask. Stirring was performed for 4 hours while heating each flask to 130 ° C. to dissolve each piece. The solution was filtered with a wire mesh of 106 μm in a high temperature state of 130 ° C. The insoluble matter on the wire mesh was dried at 140 ° C. for 3 hours under vacuum conditions, and the weight (g) of the insoluble matter after ambient temperature was measured. Then, the gel fraction was determined by the following formula: gel fraction (%) = weight of insoluble matter (g) × 100 / 0.3 (g).

In the composition preparation step, PAI varnish and each solid lubricant are blended at the blending ratio shown in Table 2 and thoroughly stirred, and then passed through a 3-roll mill to slide in Examples 1-4 and Comparative Examples 1-3. A composition for layers was prepared. The solid lubricant consists of PTFE particles, UHPE particles, MoS ₂ and graphite. UHPE particles are non-crosslinked products, cross-linked product no. It is either 1-4 or a non-hermetic crosslinked product.

The following slide layer formation process was performed. First, each sliding layer composition is diluted with a solvent to be a diluted product, and each diluted product is coated on a base material made of steel material, and then dried and fired at 220 ° C. for 1.5 hours. The Thereafter, surface grinding was performed to make the film thickness the same, and a sliding layer with a film thickness of 15 μm was formed. Thus, the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3 were obtained.

Each sliding member comprises a base material and a sliding layer formed on the base material. The sliding layer contains a binder resin and a solid lubricant. Each sliding member was subjected to the following tests 1 to 3.

<Test 1 (Pin-on-disc reciprocating test)>
This test confirms the appearance of elution (residue) of UHPE particles in the sliding layer of each sliding member. That is, as shown in FIG. 1, each sliding member 10 is placed on the plate 1 capable of heating the upper surface. In this state, each sliding member 10 has the sliding layer 10a as the upper surface. On the sliding layer 10a, the pin 2 made of SUJ2 and having a curvature of 10R at its tip is reciprocated under the load 350 gf, the reciprocation distance 20 mm, the speed 2 Hz, and the number of reciprocations 3500 times. At this time, the temperature of the substrate surface is controlled to 80 ° C., and the lubricant 3 containing hydrocarbon oil is dropped onto the sliding layer 10 a. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

<Test 2 (swash plate x shoe test 1)>
This test is to evaluate the coefficient of friction and the sticking property in a dry environment in a swash plate type compressor. That is, as shown in FIG. 2, the base material 20 was made into the swash plate shape of a compressor, and the sliding layer 20a was formed in each base material 20 similarly to the above, and the swash plate was obtained. On the other hand, the shoe 4 made of SUJ 2 was held in the holder 4. Then, while rotating the swash plate at a sliding speed of 10 m / sec, a load 1960 N was applied between the swash plate and the shoe 5, and the time (seconds) for the swash plate and the shoe 5 to burn was examined. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

<Test 3 (swash plate x shoe test 2)>
This test is to evaluate the sticking property when applying a step load under lubrication in oil in a swash plate type compressor. That is, as shown in FIG. 2, the base material 20 was made into the swash plate shape of a compressor, and the sliding layer 20a was formed in each base material 20 similarly to the above, and the swash plate was obtained. On the other hand, the shoe 4 made of SUJ 2 was held in the holder 4. And while making a swash plate 7 m / s slide speed while making a refrigerator oil adhere in the quantity of 6 g / min on the surface of a swash plate, while applying a load 400N every five minutes between swash plate and shoe 5 The load (N) at which the swash plate and the shoe 5 seize was examined. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

The results are shown in Table 3. Further, the remaining state of the UHPE particles in the sliding layer of each sliding member of Examples 1 to 4 and Comparative Examples 2 and 3 after the test 1 was confirmed by the SEM image. In the sliding member of Example 1, a 500 × SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 2, the 500 times SEM image photograph in the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 3, a 500 × SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 4, the 500 times SEM image photograph in the sliding layer of Test 1 is shown in FIG. In the sliding member of Comparative Example 2, a 500 × SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Comparative Example 3, a 500 × SEM image photograph of the sliding layer of Test 1 is shown in FIG.

As can be seen from Table 3, the sliding members of Examples 1 to 4 can exhibit excellent seizure resistance and abrasion resistance. The reason for this is presumed that the sliding members of Examples 1 to 4 adopt UHPE particles irradiated with radiation in a closed state, so that the UHPE particles are not easily oxidized and are appropriately crosslinked. .

In particular, in the sliding members of Examples 2 to 4, the sliding layer exhibits excellent seizure resistance and wear resistance. This is because, as shown in Table 1, the sliding members of Examples 2 to 4 have melting points of 128.2 ° C. or more and 132.0 ° C. because the absorbed dose of the electron beam is 60 kGy or more and 300 kGy or less. Since crosslinked UHPE particles having a C or less and a gel fraction of 26% or more are employed, as shown in FIGS. 4 to 6, the UHPE particles are eluted and dropped from the surface of the sliding layer at high temperatures. It is guessed that it is difficult to do.

On the other hand, as can be seen from Table 3, the sliding members of Comparative Examples 2 and 3 have a low seizure load and are inferior in seizure resistance. This is because the sliding member of Comparative Example 2 adopts non-crosslinked UHPE particles, and therefore, as shown in FIG. 7, the UHPE particles are easily eluted and detached from the surface of the sliding layer at high temperatures. It is guessed that there is. Furthermore, since the sliding member of Comparative Example 3 adopts UHPE particles of a non-closed crosslinked product having a gel fraction of 0%, the UHPE particles are not oxidized and are not appropriately crosslinked, as shown in FIG. It is surmised that the reason is that UHPE particles are easily eluted and detached from the surface of the sliding layer at high temperatures.

Therefore, in the sliding members of Examples 1 to 4 and particularly the sliding members of Examples 2 to 4, the sliding layer can exhibit excellent sliding characteristics in terms of self-lubricity, wear resistance and heat resistance. Recognize. For this reason, it can be understood that a more excellent compressor can be obtained by adopting these sliding members as a swash plate or the like of the compressor.

(2nd experiment)
Next, Examples 5 to 18 and Comparative Examples 4 to 8 embodying the present invention will be described. First, as in the first experiment, PAI varnish and each solid lubricant were compounded at the mixing ratio shown in Tables 4 to 6 as a composition preparation step, and after thorough stirring, they were passed through a three-roll mill to obtain Examples 5 to The sliding layer compositions of 18 and Comparative Examples 4 to 8 were prepared. And the sliding layer formation process was performed like 1st experiment. Thus, the sliding members of Examples 5 to 18 and Comparative Examples 4 to 8 were obtained.

The respective sliding members of Examples 1 to 4 and Comparative Examples 1 and 2 obtained in the first experiment, and the respective members of Examples 5 to 18 and Comparative Examples 4 to 8 obtained in the second experiment are described below. The samples were subjected to Tests 4 and 5.

<Test 4 (Ring on disc friction and wear test: under dry environment)>
This test is to evaluate the wear resistance under a certain level of dry environment in the sliding layer of each sliding member. That is, as shown in FIG. 9, the sliding layer 30a of each sliding member is formed on the upper surface of the base material 30 made of S45C. The film thickness of the sliding layer 30a is about 20 μm. In this state, the ring 6 is placed on the upper surface of the sliding layer 30a of each sliding member. The ring 6 made of S45C is rotated under the conditions of a surface pressure of 5.4 MPa, a sliding speed of 0.9 m / sec, and a sliding distance of 500 m. The specific wear amount (× 10 ⁻⁶ mm ³ / N · m) of the sliding layer 30 a during this time was measured. This test was performed on the sliding members of Examples 1 to 18 and Comparative Examples 1, 2 and 4 to 8.

<Test 5 (Pin-on-disk friction and wear test: in oil environment)>
This test evaluates the abrasion resistance under a constant level of oil environment in the sliding layer of each sliding member. That is, as shown in FIG. 10, the sliding layer 40a of each sliding member is formed on the upper surface of the base material 40 made of S45C. The film thickness of the sliding layer 40 a is about 15 μm. In this state, the pin 7 is placed on the upper surface of the sliding layer 40a of each sliding member. A pin 7 made of SUJ2 and having a tip curvature of 10R is rotated under a load of 20 N, a sliding speed of 0.25 m / sec, and a sliding distance of 22.6 m. At this time, 5 mg of refrigerator oil 8 was dropped on the sliding layer 40a, and the wear depth of the sliding layer 40a was measured. This test was performed on the sliding members of Examples 1 to 18 and Comparative Examples 1, 2 and 4 to 8.

Table 7 shows the results of Tests 4 and 5 in the sliding members of Examples 1 to 4 and Comparative Examples 1 and 2. Tables 8 to 10 show the results of Test 4 and Test 5 in the sliding members of Examples 5 to 18 and Comparative Examples 4 to 8.

In evaluating the wear resistance of the sliding members of Examples 1 to 18, the wear resistance of the sliding member of Comparative Example 2 was used as a criterion. The reason is as can be seen from Tables 2 and 4 to 6. While the sliding members of Examples 1 to 18 have the UHPE particles crosslinked appropriately, the sliding members of the comparative example 2 have the UHPE particles crosslinked. This is because the presence or absence of crosslinking of the UHPE particles is used as a judgment standard because it is not used.

As can be seen from Tables 7 to 10, each sliding member of Examples 1 to 18 had a specific wear amount of 3.6 (×, based on the results of Tests 4 and 5 in the sliding member of Comparative Example 2). Less than 10 ⁻⁶ mm ³ / N · m) or less than the wear depth of 9.1 (μm). That is, the sliding members of Examples 1 to 18 can exhibit excellent wear resistance in a dry environment or in an oil environment. It is presumed that this is because the sliding members of Examples 1 to 18 employ UHPE particles irradiated with radiation in a sealed state, so that the UHPE particles are not easily oxidized and are appropriately crosslinked. . In particular, in the sliding members of Examples 1 to 3 and 5 to 12, the sliding layer exhibits excellent abrasion resistance in a dry environment and in an oil environment.

Further, as shown in Table 1, the sliding members of Examples 1 to 18 have melting points exceeding 126.4 ° C. and 132.0 ° when the absorbed dose of the electron beam is 60 kGy or more and less than 500 kGy. Since crosslinked UHPE particles having a C or less and a gel fraction of 26% or more are employed, it is presumed that the UHPE particles do not easily elute or fall off from the surface of the sliding layer at high temperatures.

On the other hand, as can be seen from Tables 7 to 10, the sliding members of Comparative Examples 1, 2, 4 and 5 have specific wear amounts of 3.6 (× 10 ⁻⁶ mm ³ / N) in the results of Tests 4 and 5. · M) or more, and the wear depth is 9.1 (μm) or more. For this reason, the sliding members of Comparative Examples 1, 2, 4, and 5 are inferior in abrasion resistance in either a dry environment or in an oil environment as compared with the sliding members of Examples 1 to 18. ing. Since the sliding member of Comparative Example 1 adopts a fluorine compound (PTFE particles) instead of appropriately crosslinked UHPE particles, it is surmised that the wear resistance is inferior. Since the sliding member of Comparative Example 2 adopts uncrosslinked UHPE particles having a melting point of 134.6 ° C., it is speculated that the UHPE particles are easily eluted and separated from the surface of the sliding layer at high temperatures. Be done. Furthermore, in the sliding members of Comparative Examples 4 and 5, since the absorbed dose of the electron beam is 500 kGy or more, it is inferred that the crosslinked UHPE particles become brittle and the wear resistance of the sliding members is deteriorated.

Therefore, it can be seen that the sliding members of Examples 1 to 18 can exhibit excellent abrasion resistance in a dry environment or in an oil environment. In particular, in the sliding members of Examples 1 to 3 and 5 to 12, the sliding layer can exhibit excellent abrasion resistance in a dry environment and in an oil environment.

In the sliding layer, the solid lubricant is 25% by volume or more and 100% by volume or less with respect to the binder resin, and the ultra high molecular weight polyethylene is 5% by volume or more and 35% by volume or less with respect to the total solid component in the sliding layer Is preferred. More specifically, the sliding members of Examples 1 to 18 can exhibit excellent abrasion resistance to the sliding members of Comparative Examples 6 to 8 in a dry environment or in an oil environment. That is, in the sliding members of Comparative Examples 6 to 8, the specific wear amount exceeded 3.6 (× 10 ⁻⁶ mm ³ / N · m) in all of the results of Tests 4 and 5, and the wear depth was Is more than 9.1 (μm). In the sliding members of Comparative Examples 6 to 8, since the solid lubricant is 150% by volume with respect to the binder resin, the binder resin can not hold the fixed lubricant, and the solid lubricant comes from the surface of the sliding layer at high temperatures. It is guessed that it is because it fell out.

In the sliding layer, it is preferable that molybdenum disulfide is 26% by volume or less with respect to the total solid component in the sliding layer. In this case, the sliding layer can further improve the wear resistance in a dry environment or in an oil environment. Further, as in the sliding members of Examples 7 and 12, molybdenum dioxide may not be contained in the solid lubricant.

In the sliding layer, the ultrahigh molecular weight polyethylene is 23% by volume or more and 35% by volume or less with respect to the total solid component in the sliding layer, and the molybdenum disulfide is 15% by volume or less with respect to the total solid component in the sliding layer Is preferred. In this case, the sliding layer can further improve the wear resistance, particularly in a dry environment. More specifically, the sliding members of Examples 5 to 8 can exhibit excellent abrasion resistance in a dry environment. The sliding members of Examples 5 to 8 have a specific wear amount in the range of 0.5 to 1.3 (× 10 ⁻⁶ mm ³ / N · m) in Test 4 and are compared with the other Examples. And show remarkable effects.

In the sliding layer, graphite is preferably 5% by volume or more and 30% by volume or less with respect to the total solid component in the sliding layer. In this case, the sliding layer can further improve the wear resistance under dry environment or under oil environment. Also, as in the sliding members of Examples 16 and 18, graphite may not be contained in the solid lubricant.

Although the present invention has been described above in connection with the first to eighteenth embodiments, the present invention is not limited to the first to eighteenth embodiments, and can be appropriately modified and applied without departing from the scope of the present invention. Needless to say.

For example, in the present invention, in order to enhance the adhesion between the base material and the sliding layer, it is possible to carry out a degreasing step in which an alkali or the like is brought into contact with the base material. Moreover, in order to further enhance the adhesion between the base material and the sliding layer, it is possible to form an underlayer comprising a phosphate such as zinc phosphate or manganese phosphate after the degreasing step.

The present invention is applicable to various sliding members.

2, 5, 6, 7 ... partner material (2, 7 ... pin, 5 ... shoe, 6 ... ring)
DESCRIPTION OF SYMBOLS 10 ... Sliding member 20, 30, 40 ... Base material 10a, 30a, 40a ... Sliding layer

Claims (8)

A manufacturing method of a sliding member for manufacturing a sliding member sliding with a mating member,
Irradiating the particulate ultra high molecular weight polyethylene in a closed state with radiation to crosslink the ultra high molecular weight polyethylene;
A composition preparation step of preparing a composition for a sliding layer containing a solid lubricant containing the ultra-high molecular weight polyethylene crosslinked in the crosslinking step, and a binder resin;
And a sliding layer forming step of providing the sliding layer composition on a base material to form a sliding layer sliding on the other member, and obtaining a sliding member. Method of manufacturing a member The method for manufacturing a sliding member according to claim 1, wherein the crosslinking step is performed under the condition that the absorbed dose of the electron beam as the radiation is 60 kGy or more and less than 500 kGy. A sliding member comprising: a base material; and a sliding layer formed on the base material and containing a binder resin and a solid lubricant, wherein the sliding layer slides on a mating material,
The sliding member characterized in that the solid lubricant is in the form of particles and has a melting point of higher than 126.4 ° C. and 132.0 ° C. or less. The sliding member according to claim 3, wherein the ultrahigh molecular weight polyethylene has a gel fraction of 26% or more. In the sliding layer, the solid lubricant is 25% by volume or more and 100% by volume or less with respect to the binder resin,
In the sliding layer, the binder resin is polyamide imide,
The sliding member according to claim 3 or 4, wherein the ultra high molecular weight polyethylene is 5% by volume or more and 35% by volume or less with respect to the total solid component in the sliding layer. The solid lubricant further comprises molybdenum disulfide,
The sliding member according to claim 5, wherein in the sliding layer, the molybdenum disulfide is 26% by volume or less with respect to the total solid component in the sliding layer. In the sliding layer, the ultrahigh molecular weight polyethylene is 23% by volume or more and 35% by volume or less based on the total solid component in the sliding layer, and the molybdenum disulfide is relative to the total solid component in the sliding layer The sliding member according to claim 6, which is at most 15% by volume. The solid lubricant further comprises graphite,
The sliding member according to any one of claims 5 to 7, wherein the content of the graphite in the sliding layer is 5% by volume or more and 30% by volume or less with respect to the total solid component in the sliding layer.

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