KR20200086705A - Sliding member and method for manufacturing the same - Google Patents

Abstract

Provided is a sliding member capable of exhibiting excellent sliding properties in terms of seizure resistance, abrasion resistance and heat resistance. The manufacturing method of the sliding member of this invention is a manufacturing method of the sliding member for manufacturing the sliding member which slides with a mating material. This manufacturing method includes a crosslinking step of irradiating the ultra-high-molecular-weight polyethylene in a sealed state and crosslinking the ultra-high-molecular-weight polyethylene, and a composition preparation step of preparing a composition for a sliding layer containing a solid lubricant and a binder resin. , By providing a composition for a sliding layer on a base material to form a sliding layer that slides with a counterpart, and a sliding layer forming process for obtaining a sliding member. The solid lubricant contains ultrahigh molecular weight polyethylene crosslinked in a crosslinking process.

Description

Sliding member and method for manufacturing the same

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

Conventionally, the sliding member disclosed in patent documents 1 and 2 is known. These sliding members are provided with a base material made of a steel material or an aluminum material, and a sliding layer formed on the base material. In some cases, an underlayer is 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 an 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 viewpoint of characteristics of self-lubricating properties and abrasion resistance, and the solid lubricant of Patent Document 2 includes ultrahigh molecular weight polyethylene in which the particulate phase is crosslinked.

These sliding members can be employed in propeller shafts, pistons, and the like in which the sliding layer slides with the mating material. In particular, in the sliding layer of Patent Document 1, since polyethylene having good affinity with a lubricant is contained as a solid lubricant, it is trying to realize low friction coefficient and high wear resistance. In addition, in the sliding layer of Patent Document 2, cross-linked ultra-high molecular weight polyethylene is used as a solid lubricant, and in addition to seizure resistance and abrasion resistance, high heat resistance is also to be realized.

Japanese Patent Publication No. 2013-189569 Japanese Patent Publication No. 2016-69508

However, in order to secure reliability, it is desired for the sliding member to further improve sliding characteristics. In this regard, according to the test results of the inventors, even if cross-linked ultra-high molecular weight polyethylene is employed as part of the solid lubricant, the sliding mobile layer cannot necessarily exhibit high heat resistance as long as the cross-linked ultra-high molecular weight polyethylene is simply irradiated with radiation. . In some cases, the crosslinked ultra-high molecular weight polyethylene becomes fragile, and rather the lubrication properties of the sliding layer deteriorate.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object to be solved is to provide a sliding member capable of exerting excellent sliding properties in terms of seizure resistance, abrasion resistance and heat resistance.

The manufacturing method of the sliding member of this invention is a manufacturing method of the sliding member for manufacturing the sliding member which slides with a mating material,

A crosslinking step of irradiating the ultra-high molecular weight polyethylene in a sealed state and crosslinking the ultrahigh molecular weight polyethylene;

A composition preparation process for preparing a composition for a sliding layer containing a solid lubricant comprising the ultra-high molecular weight polyethylene crosslinked in the crosslinking process and a binder resin,

It is characterized in that the composition for the sliding layer is provided on the base material to form a sliding layer that slides with the counterpart, and a sliding layer forming process for obtaining a sliding member is provided.

According to the test results of the inventors, in the sliding member obtained in the production method of the present invention, it is possible to improve excellent seizure resistance and wear resistance by appropriately crosslinked ultrahigh molecular weight polyethylene. This reason is presumed to be because, in the manufacturing method of the present invention, in the crosslinking step, since the ultra-high molecular weight polyethylene in the particulate state is irradiated with radiation in a closed state, the ultrahigh molecular weight polyethylene is hardly oxidized and is appropriately crosslinked. When the ultra-high molecular weight polyethylene is irradiated with radiation in an open atmosphere, the ultrahigh molecular weight polyethylene is oxidized, making it difficult to crosslink the ultrahigh molecular weight polyethylene.

According to the test results of the inventors, it is preferable that the crosslinking step is performed under the conditions where the absorbed dose of electron beams as radiation is 60 kGy or more and less than 500 kGy. The electron beam is convenient for handling. When the electron beam is irradiated with the absorbed dose in this range, ultrahigh molecular weight polyethylene is appropriately crosslinked, and the sliding layer exhibits excellent heat resistance and abrasion resistance. When a crosslinking step is performed in which the absorbed dose of the electron beam is less than 60 kGy, crosslinking of the ultrahigh molecular weight polyethylene is insufficient, and the wear resistance of the sliding layer is insufficient. When the crosslinking step is performed at an absorption amount of an electron beam of 500 kGy or more, the crosslinked ultra-high molecular weight polyethylene is fragile, and the wear resistance of the sliding layer is deteriorated.

The sliding member of the present invention is a sliding member that is formed on the base material, the base material, and includes a sliding layer containing a binder resin and a solid lubricant, and the sliding layer slides with a counterpart,

The solid lubricant is characterized in that it comprises a cross-linked ultra-high molecular weight polyethylene having a particle shape, a melting point of more than 126.4 ℃, 132.0 ℃ or less.

According to the test results of the inventors, when the melting point of the ultrahigh molecular weight polyethylene is within this range, the coefficient of friction of the sliding layer is low, the amount of wear is low, and the ultrahigh molecular weight polyethylene is eluted and eliminated from the surface of the sliding layer at high temperatures. It is difficult. It is presumed that the ultrahigh molecular weight polyethylene is properly crosslinked. For this reason, it is possible to improve the sintering resistance and abrasion resistance which are excellent in the sliding layer.

According to the test results of the inventors, it is preferable that the ultra high molecular weight polyethylene 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 ultrahigh molecular weight polyethylene is difficult to elute from the surface of the sliding layer at high temperatures. It is assumed that the ultra high molecular weight polyethylene having a gel fraction in this range is appropriately crosslinked.

According to the test results of the inventors, the sliding layer preferably has a solid lubricant of 25% by volume or more and 100% by volume or less of the binder resin. In this case, the binder resin can hold the fixed lubricant more. Moreover, it is preferable that a binder resin is a polyamideimide in the sliding layer. Moreover, it is preferable that ultra high molecular weight polyethylene is 5 volume% or more and 35 volume% or less with respect to the whole solid component in a sliding layer. In this case, the sliding layer can further improve abrasion resistance in a dry environment or in an oily environment.

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

According to the test results of the inventors, in the sliding layer, the ultra-high molecular weight polyethylene is 23% by volume or more and 35% by volume or less relative to the total solid components in the sliding layer, and molybdenum disulfide is the entire solid component in the sliding layer. It is preferably 15% by volume or less. In this case, the sliding layer can further improve abrasion resistance, particularly in a dry environment.

According to the test results of the inventors, it is preferable that the solid lubricant further contains graphite. Moreover, it is preferable that graphite is 5 volume% or more and 30 volume% or less with respect to the whole solid component in a sliding layer. In this case, the sliding layer can further improve abrasion resistance in a dry environment or in an oily environment.

By the manufacturing method of the present invention, a sliding member capable of exhibiting excellent sliding characteristics in terms of seizure resistance, abrasion resistance and heat resistance can be produced. Further, according to the sliding member of the present invention, the sliding layer can exhibit excellent sliding properties in terms of self-lubricating properties, abrasion resistance and heat resistance.

1 is a schematic perspective view showing an aspect of a pin-on-disc reciprocation test in Test 1.
2 is a cross-sectional view showing an aspect of an inclined plate x shoe test in Test 2.
3 is a 500-fold SEM image of the sliding member in Test 1 in the sliding member of Example 1.
4 is a 500-fold SEM image of the sliding member in Test 2 in the sliding member of Example 2.
5 is a 500-fold SEM image of the sliding member in Test 1 in the sliding member of Example 3.
6 is a 500-fold SEM image of the sliding member in Test 1 in the sliding member of Example 4.
7 is a 500-fold SEM image of the sliding member of Test 1 in the sliding member of Comparative Example 2.
8 is a SEM image photograph of 500 times in the sliding layer of Test 1 in the sliding member of Comparative Example 3.
9 is a schematic perspective view showing an aspect of a ring-on-disk friction wear test in Test 4.
10 is a schematic perspective view showing an aspect of a pin-on-disk friction wear test in Test 5.

<Crosslinking process>

As a means for irradiating the ultra-high molecular weight polyethylene in a sealed state, (1) a vacuum method for vacuum-suctioning the inside of the container containing the particulate ultra-high molecular weight polyethylene and lowering the abundance of air, and (2) the inside of the container. A gas purging method for filling with an inert gas or nitrogen and discharging air can be employed. If sealed, an atmosphere containing some oxygen may be used without using a vacuum method or a gas purge method.

As radiation, X-rays, electron beams, and ion beams can be employed in addition to α-rays, β-rays, and γ-rays. The amount of radiation is expressed as a dose proportional to the energy absorbed by the unit mass. Gy is a unit that represents the amount of energy (called absorbed dose) absorbed by a substance when radiation hits a substance.

<Composition preparation process>

(Binder resin)

The binder resin exhibits the retainability of the solid lubricant, which makes it difficult to remove the solid lubricant, the durability against the shearing force (hardness as a base) that repeatedly acts under the layered coating, the abrasion resistance, and the heat resistance. As the binder resin, polyimide resin, epoxy resin, phenol resin, or the like can be adopted. As the polyimide resin, polyamideimide (PAI), polyimide, or the like can be employed. Considering cost and characteristics, it is optimal to use PAI as a binder resin.

(Solid lubricant)

The solid lubricant is retained in the binder resin and exhibits low shear force and low friction coefficient at the outermost surface. As the solid lubricant, fluorine resin, molybdenum dioxide, graphite, ultra high molecular weight polyethylene, or the like can be employed. The fluororesin and ultra-high molecular weight polyethylene form a film on the sliding surface of the sliding layer, and further improve the sliding property by being adhered to the mating material. Molybdenum dioxide and graphite have improved slidability due to a crystal structure having a low shear force, and realize low friction at high loads. According to the test results of the inventors, the fluororesin has sliding properties such as abrasion resistance and seizure resistance, but has oil repellent properties, and the contact angle of the lubricant is relatively large. On the other hand, ultra-high molecular weight polyethylene is less slippery than fluorine resin in sliding properties, but has lipophilic properties, and the contact angle of the lubricant is relatively small. Further, as a solid lubricant, soft metals such as melamine cyanurate (MCA), calcium fluoride, copper, and tin can be employed. Particularly, the ultra-high molecular weight polyethylene, which is properly crosslinked, is difficult to elute from the surface of the sliding layer at high temperatures, and thus can improve excellent seizure resistance and wear resistance.

It is preferable that the ultra high molecular weight polyethylene before crosslinking has an average molecular weight of 1 to 7 million. Further, the specific gravity of the ultra-high molecular weight polyethylene before crosslinking is preferably 0.92 to 0.96. From the viewpoint of surface smoothness and wear resistance, the ultra-high molecular weight polyethylene before crosslinking is preferably 30 µm or less in particle diameter, and more preferably 15 µm or less.

(Additives, etc.)

The sliding layer may have additives in addition to the binder resin and the solid lubricant. As an additive, it is possible to adopt one that improves the hardness of the sliding layer, such as hard particles such as titanium dioxide, tricalcium phosphate, alumina, silica, silicon carbide, and silicon nitride.

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

As a silane coupling agent used for a silane coupling treatment, it is preferable that a functional group is an epoxy group. As a silane coupling agent having an epoxy group in a functional group, 2-(3,4 epoxycyclohexyl) ethyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-glycine Cydoxypropyltriethoxysilane is preferred. They are also excellent in storage stability.

<Sliding mobile layer formation process>

As the step of forming the sliding layer, depending on the type of coating method such as spray coating or roll coating, optionally, solvents such as n-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, xylene, etc. It is possible to dilute the composition for the sliding layer and adjust the viscosity and the concentration of the solid content. After coating the base material with a dilution of the composition for a sliding layer, it is possible to dry and fire to form a sliding layer.

Example

(First experiment)

Hereinafter, Examples 1 to 4 and Comparative Examples 1 to 3 embodying the present invention will be described. First, the following materials were prepared.

Binder resin: polyamideimide resin (PAI) varnish

Solid lubricants: particulate ultra-high molecular weight polyethylene (UHPE particles), particulate fluorine compounds (PTFE particles), MoS ₂ , graphite

Airtight, and a plurality of plastic bags of the same size were prepared, a certain amount of UHPE particles were put in them, and the inside of each bag was vacuumed under the same conditions. Thereafter, each bag was put in an electron beam irradiation apparatus, and the UHPE particles were irradiated with electron beams as radiation with the absorbed dose (kGy) shown in Table 1. In this way, the crosslinked product No. UHPE particles of 1 to 4 were obtained. The UHPE particles of the uncrosslinked product did not undergo electron beam irradiation. The UHPE particles of the non-closed crosslinked product are those in which the electron beam is irradiated without being placed in an open air state, that is, in a bag.

Table 1 shows the melting point (°C), gel fraction (%), and average particle diameter (µm) of each UHPE particle. In addition, Table 1 also shows the melting point (°C) and average particle diameter (µm) of the PTFE particles.

Here, the measurement conditions of the melting point are as follows.

Analytical device: DSC Q2000 (TA instrument)

Heating rate: 5°C/min (after heating to 210°C, cool from -20°C/min to 30°C and measure again)

Atmosphere: N ₂

Sample weight: 5mg±0.1mg each

Reading condition of melting point: Peak temperature of melting at the time of measurement again

The gel fraction was measured as follows. First, each powder was molded into a sheet having a thickness of 0.3 mm by pressing at a constant pressure while heating at 180°C to 230°C. 0.3 g of small pieces were cut from each sheet. Each piece was placed in a flask, and 500 ml of p-xylene was added into the flask. Each flask was stirred for 4 hours while heating to 130°C to dissolve each piece. The solution was filtered through a metal mesh having a mesh of 106 µm while maintaining a high temperature of 130°C. The insoluble material on the metal net was dried at 140° C. for 3 hours under vacuum, and the weight (g) of the insoluble material after room temperature was measured. And the gel fraction (%) = the gel fraction was calculated|required by the calculation formula of weight (g) x 100/0.3 (g) of insoluble matter.

As a composition preparation step, the PAI varnish and each solid lubricant were blended at a blending ratio shown in Table 2, and after stirring well, three roll mills were passed through the composition for sliding layers of Examples 1 to 4 and Comparative Examples 1 to 3. Was prepared. The solid lubricant is composed of PTFE particles, UHPE particles, MoS ₂ and graphite. The UHPE particles are either uncrosslinked products, crosslinked products No. 1 to 4, or non-closed crosslinked products.

The following sliding layer formation process was performed. First, the composition for each sliding layer was diluted with a solvent to form a diluent, and each diluent was coated on a base material made of steel, followed by drying and firing at 220° C.×1.5 hours. Thereafter, surface grinding was performed to make the film thickness the same, and a sliding layer having 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 is composed of 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 provided in the following tests 1-3.

<Test 1 (Pin-on-disk reciprocating test)>

This test confirms the mode of elution (remaining) of UHPE particles in the sliding layer of each sliding member. That is, as shown in FIG. 1, each sliding member 10 is mounted on a plate 1 capable of heating an upper surface. In this state, in each sliding member 10, the sliding layer 10a has an upper surface. On the sliding layer 10a, the pin 2, which is made of SUJ2 and has a curvature at the tip of 10R, is reciprocated under conditions of a load of 350 gf, a reciprocating distance of 20 mm, a speed of 2 kPa, and a reciprocating number of 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 10a. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

<Test 2 (Slope Test × Shoe Test 1)>

This test evaluates the coefficient of friction and seizure in a dry environment in an inclined plate type compressor. That is, as shown in FIG. 2, the base material 20 was made into the shape of an inclined plate of a compressor, and as described above, a sliding layer 20a was formed on each base material 20 to obtain an inclined plate. On the other hand, the shoe 5 made of SUJ2 was held in the holding tool 4. Then, while rotating the inclined plate at a sliding speed of 10 m/sec, a load of 1960N was applied between the inclined plate and the shoe 5, and the time (second) in which the inclined plate and the shoe 5 were pressed was examined. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

<Test 3 (Slant Plate X Shoe Test 2)>

This test evaluates the seizure property when adding a step load under oil lubrication in an inclined plate type compressor. That is, as shown in FIG. 2, the base material 20 was made into the shape of an inclined plate of a compressor, and as described above, a sliding layer 20a was formed on each base material 20 to obtain an inclined plate. On the other hand, the shoe 5 made of SUJ2 was held in the holding tool 4. Then, while attaching the refrigerating machine oil to the surface of the inclined plate in an amount of 6 g/min, rotate the inclined plate at a sliding speed of 7 m/sec, and add a load of 400 N every 5 minutes between the inclined plate and the shoe 5 to increase the inclined plate and the shoe. The load (N) that (5) was applied to was investigated. This test was performed on the sliding members of Examples 1 to 4 and Comparative Examples 1 to 3.

Table 3 shows these results. In addition, the residual state of UHPE particles in the sliding layer of each of the sliding members of Examples 1 to 4 and Comparative Examples 2 and 3 after Test 1 was confirmed by SEM images. In the sliding member of Example 1, the SEM image photograph of 500 times in the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 2, the SEM image photograph 500 times in the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 3, the SEM image photograph 500 times in the sliding layer of Test 1 is shown in FIG. 5. In the sliding member of Example 4, a SEM image photograph of 500 times in the sliding layer of Test 1 is shown in FIG. 6. In the sliding member of Comparative Example 2, a SEM image photograph of 500 times in the sliding layer of Test 1 is shown in FIG. 7. In the sliding member of Comparative Example 3, a 500-times SEM image photograph of the sliding layer of Test 1 is shown in FIG. 8.

As can be seen from Table 3, the sliding members of Examples 1 to 4 can exhibit excellent seizure resistance and wear resistance. The reason for this is presumed to be because the sliding members of Examples 1 to 4 employ UHPE particles irradiated with radiation in a closed state, so that the UHPE particles are hardly oxidized and crosslinked appropriately.

Particularly, the sliding members of Examples 2 to 4 exhibit excellent seizure resistance and wear resistance of the sliding layer. As for the sliding members of Examples 2 to 4, as shown in Table 1, the absorbed dose of the electron beam was 60 kGy or more and 300 kGy or less, and the melting point was 128.2°C or more and 132.0°C or less, and the gel fraction was 26%. Since the crosslinked UHPE particles are employed as described above, it is presumed that, as shown in FIGS. 4 to 6, UHPE particles are unlikely to elute and fall off from the surface of the sliding layer at high temperatures.

On the other hand, as can be seen from Table 3, the sliding members of Comparative Examples 2 and 3 had a low pressing force and inferior seizure resistance. This is because the sliding member of Comparative Example 2 employs UHPE particles of uncrosslinked product, and as shown in FIG. 7, it is presumed that UHPE particles are likely to elute and fall off from the surface of the sliding layer at high temperatures. do. In addition, since the sliding member of Comparative Example 3 employs UHPE particles of an unsealed crosslinked product having a gel fraction of 0%, UHPE particles are oxidized and are not crosslinked properly, and as shown in FIG. 8, high temperature It is presumed to be because UHPE particles are easily eluted and detached from the surface of the sliding layer at the time.

Therefore, it can be seen that, in the sliding members of Examples 1 to 4, particularly of the sliding members of Examples 2 to 4, the sliding layer can exhibit excellent sliding properties in terms of self-lubricating properties, abrasion resistance and heat resistance. . For this reason, it can be seen that by employing these sliding members, a more excellent compressor can be obtained.

(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, as a composition preparation step, the PAI varnish and each solid lubricant were blended at the blending ratios shown in Tables 4 to 6, and stirred well, and then passed through three roll mills, Examples 5 to 18, and The compositions for sliding layers of Comparative Examples 4 to 8 were prepared. Then, as in the first experiment, a step of forming a sliding layer was performed. Thus, the sliding members of Examples 5 to 18 and Comparative Examples 4 to 8 were obtained.

Each of the sliding members of Examples 1 to 4 and Comparative Examples 1 and 2 obtained in the first experiment and each of the sliding members of Examples 5 to 18 and Comparative Examples 4 to 8 obtained in the second experiment were tested as follows. Provided in 5.

<Test 4 (Ring on disk friction wear test: under dry environment)>

This test evaluates the abrasion 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 mounted on the upper surface of the sliding layer 30a of each sliding member. The ring 6 made of S45C is rotated under 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 non-wear amount (x10 ^-6 Pa/Nm) of the sliding layer 30a in between 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 wear test: under oil environment)>

This test evaluates the abrasion resistance under a certain level of oil in the 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 40a is about 15 μm. In this state, the pin 7 is mounted on the upper surface of the sliding layer 40a of each sliding member. The pin 7, which is made of SUJ2 and has a curvature at the tip of 10R, is rotated under conditions of a load of 20N, a sliding speed of 0.25 m/sec, and a sliding distance of 22.6 m. At this time, 5 mg of the refrigerator oil 8 was dropped onto the sliding layer 40a, and the wear depth of the sliding layer 40a therebetween 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 Tests 4 and 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 abrasion resistance of the sliding members of Comparative Example 2 was used as a judgment criterion. For this reason, as can be seen from Tables 2 and 4 to 6, the sliding member of Examples 1 to 18 had UHPE particles appropriately crosslinked, whereas the sliding member of Comparative Example 2 had UHPE particles crosslinked. This is because the presence or absence of crosslinking of UHPE particles was used as a judgment criterion.

As can be seen from Tables 7 to 10, when the sliding members of Examples 1 to 18 were based on the results of Tests 4 and 5 in the sliding members of Comparative Example 2, the amount of non-wear was 3.6 (× Less than 10 ^-6 mm 2 /N·m) or less than a 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 oily environment. This reason is presumed to be because the sliding members of Examples 1 to 18 employ UHPE particles irradiated with radiation in a closed state, so that the UHPE particles are hardly oxidized and are crosslinked appropriately. In particular, the sliding members of Examples 1 to 3 and 5 to 12 exhibit excellent abrasion resistance of the sliding layer under a dry environment and in an oily environment.

Further, in the sliding members of Examples 1 to 18, as shown in Table 1, the absorbed dose of the electron beam was 60 kGy or more and less than 500 kGy, so that the melting point exceeded 126.4°C and was 132.0°C or less, and the gel fraction was Since UHPE particles crosslinked at 26% or more are employed, it is presumed that UHPE particles are unlikely to elute and 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 had a non-wear amount of 3.6 (×10 ^-6 Pa/N·) in the results of Tests 4 and 5. m) or higher, and a wear depth of 9.1 (µm) or higher. For this reason, the sliding members of Comparative Examples 1, 2, 4, and 5 are inferior in abrasion resistance under dry environments or in oil environments, as compared with the sliding members of Examples 1 to 18. Since the sliding member of Comparative Example 1 employs fluorine compounds (PTFE particles) instead of UHPE particles that are appropriately crosslinked, it is presumed to have poor wear resistance. The sliding member of Comparative Example 2 is presumed to be because the uncrosslinked UHPE particles having a melting point of 134.6° C. are likely to elute and drop UHPE particles from the surface of the sliding layer at high temperatures. In addition, in the sliding members of Comparative Examples 4 and 5, since the absorbed dose of the electron beam was 500 kGy or more, it was presumed that the cross-linked UHPE particles were likely to break, and the wear resistance of the sliding members was deteriorated.

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

The sliding layer preferably has a solid lubricant of 25% by volume or more and 100% by volume or less of the binder resin, and ultrahigh molecular weight polyethylene is 5% by volume or more and 35% by volume or less of the total solid components in the sliding layer. . More specifically, the sliding members of Examples 1 to 18 can exhibit excellent abrasion resistance under the dry environment or in the oil environment, relative to the sliding members of Comparative Examples 6 to 8. That is, in the results of Tests 4 and 5, the sliding members of Comparative Examples 6 to 8 all had a non-abrasion amount exceeding 3.6 (x10 ^-6 Pa/N·m), and the wear depth was 9.1 (µm). Is exceeding. The sliding members of Comparative Examples 6 to 8 are because the solid lubricant is 150% by volume relative to the binder resin, and therefore the binder resin cannot hold the fixed lubricant, and the solid lubricant is removed from the surface of the sliding layer at high temperatures. Is estimated.

In the sliding layer, it is preferable that molybdenum disulfide is 26% by volume or less based on the total solid components in the sliding layer. In this case, the sliding layer can further improve abrasion resistance in a dry environment or in an oily environment. In addition, like the sliding member of Examples 7, 12, molybdenum dioxide need not be included in the solid lubricant.

In the sliding layer, ultra-high molecular weight polyethylene is 23% by volume or more and 35% by volume or less with respect to all solid components in the sliding layer, and molybdenum disulfide is 15% by volume or less with respect to all solid components in the sliding layer. desirable. In this case, the sliding layer can further improve abrasion resistance, particularly in a dry environment. More specifically, the sliding members of Examples 5 to 8 can exhibit excellent wear resistance in a dry environment. In the test 4, the sliding members of Examples 5 to 8 had a non-abrasion amount in the range of 0.5 to 1.3 (×10 ^-6 Pa/N·m), and exhibited a remarkable effect compared to other examples.

As for the sliding layer, it is preferable that graphite is 5 volume% or more and 30 volume% or less with respect to the whole solid component in a sliding layer. In this case, the sliding layer can further improve abrasion resistance in a dry environment or in an oily environment. Further, like the sliding members of Examples 16 and 18, graphite need not be included in the solid lubricant.

In the above, the present invention has been described based on Examples 1 to 18, but the present invention is not limited to the Examples 1 to 18, but can be appropriately changed and applied without departing from the spirit. to be.

For example, in the present invention, in order to increase the adhesion between the base material and the sliding layer, it is possible to perform a degreasing step in which alkali or the like is brought into contact with the base material. Further, in order to further increase the adhesion between the base material and the sliding layer, it is also possible to form an underlayer made of a phosphate such as zinc phosphate or manganese phosphate after the degreasing step.

The present invention can be used for various sliding members.

2, 5, 6, 7: mating material (2, 7: pin, 5: shoe, 6: ring)
10: sliding member
20, 30, 40: base material
10a, 30a, 40a: sliding layer

Claims (8)

It is a manufacturing method of a sliding member for manufacturing a sliding member that slides with a counterpart,
A crosslinking step of irradiating the ultra-high molecular weight polyethylene in a sealed state and crosslinking the ultrahigh molecular weight polyethylene;
A composition preparation process for preparing a composition for a sliding layer containing a solid lubricant comprising the ultra-high molecular weight polyethylene crosslinked in the crosslinking process and a binder resin,
A method for manufacturing a sliding member, comprising a step of forming a sliding layer for sliding on the base material to form a sliding layer for sliding with the counter material, and obtaining a sliding member. . According to claim 1,
The said bridge|crosslinking process is a manufacturing method of the sliding member which is performed on the condition where the absorbed dose of the electron beam as radiation is 60 kGy or more and less than 500 kGy. It is provided on the base material, the base material, and is provided with a sliding layer containing a binder resin and a solid lubricant, the sliding layer is a sliding member that slides with the counterpart,
The solid lubricant is a sliding member, characterized in that it comprises a particulate, ultra-high molecular weight polyethylene having a melting point of more than 126.4°C and 132.0°C or less. According to claim 3,
The ultra-high molecular weight polyethylene is a sliding member having a gel fraction of 26% or more. The method of claim 3 or 4,
In the sliding layer, the solid lubricant is 25% by volume or more and 100% by volume or less relative to the binder resin,
In the sliding layer, the binder resin is polyamideimide,
The ultra-high molecular weight polyethylene is a sliding member of 5% by volume or more and 35% by volume or less with respect to the total solid components in the sliding layer. The method of claim 5,
The solid lubricant further comprises molybdenum disulfide,
The sliding layer is a sliding member in which the molybdenum disulfide is 26% by volume or less relative to the total solid component in the sliding layer. The method of claim 6,
In the sliding layer, the ultra-high molecular weight polyethylene is 23% by volume or more and 35% by volume or less with respect to the total solid components in the sliding layer, and the molybdenum disulfide is relative to the total solid components in the sliding layer. A sliding member, which is 15% by volume or less. The method according to any one of claims 5 to 7,
The solid lubricant further includes graphite,
The sliding layer is a sliding member in which the graphite is 5% by volume or more and 30% by volume or less with respect to all solid components in the sliding layer.

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