JP7539638B2 - Sliding material - Google Patents

Description

The present invention relates to a sliding material, and more specifically, to a sliding material for ensuring sliding properties.

Conventionally, sliding materials are used in rotating equipment and sliding equipment. The sliding material is, for example, a resin molded product containing a lubricant such as graphite and a binder such as phenolic resin. The sliding material is placed, for example, in the bearing parts of various rotating equipment and the seal parts of sliding equipment. The sliding material ensures slidability and reduces damage due to friction.

Sliding materials are required to have excellent sliding properties and heat resistance. Therefore, in sliding materials containing a binder, it has been proposed to include a novolac-type phenolic resin and lignin in the binder (see, for example, Patent Document 1).

JP 2020-94079 A

On the other hand, sliding materials may be required to have certain flexural properties depending on the application. Therefore, sliding materials that have excellent sliding properties and heat resistance, as well as excellent flexural properties, are required.

The present invention is a sliding material that has excellent sliding properties and heat resistance, as well as excellent flexural properties.

The present invention [1] is a sliding material containing a binder, and includes a sliding material in which the binder contains a novolac-type phenolic resin and lignin modified with polyethylene glycol.

The sliding material of the present invention contains a binder, and the binder contains a novolac-type phenolic resin and lignin modified with polyethylene glycol. Therefore, the sliding material of the present invention has excellent sliding properties and heat resistance, and further has excellent flexural properties.

The sliding material of the present invention contains a binder.

The binder contains a novolac-type phenolic resin and lignin modified with polyethylene glycol (PEG) (hereinafter, sometimes referred to as PEG-modified lignin). The binder is preferably composed of a novolac-type phenolic resin and PEG-modified lignin.

Novolac-type phenolic resins are, for example, reaction products of phenols and aldehydes in the presence of an acid catalyst.

Phenols are phenol and phenol derivatives (phenol modified products). Examples of phenols include phenol, bifunctional phenol derivatives, trifunctional phenol derivatives, and tetrafunctional phenol derivatives. Examples of bifunctional phenol derivatives include o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, 2,4-xylenol, and 2,6-xylenol. Examples of trifunctional phenol derivatives include m-cresol, resorcinol, and 3,5-xylenol. Examples of tetrafunctional phenol derivatives include bisphenol A and dihydroxydiphenylmethane. Examples of phenol derivatives also include halogenated phenols. Halogenated phenols are halides of phenol or phenol derivatives. Examples of halogens include chlorine and bromine. These phenols can be used alone or in combination of two or more types. In the derivatives of phenol, the timing at which phenol is derivatized (modified) is not particularly limited. For example, the derivatization of phenols may be performed before, after, or simultaneously with the reaction of phenols with aldehydes. As the phenols, phenol is preferably used.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, furfural, glyoxal, benzaldehyde, trioxane, and tetraoxane. In addition, a part of the aldehyde may be substituted with furfuryl alcohol or the like. These aldehydes may be used alone or in combination of two or more kinds. Preferred examples of aldehydes include formaldehyde and paraformaldehyde.

The aldehydes can also be used, for example, as an aqueous solution. In such a case, the concentration of the aldehydes is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 99% by mass or less, preferably 95% by mass or less.

Ketones can also be blended together with aldehydes. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, acetophenone, and diphenyl ketone. These ketones can be used alone or in combination of two or more. When ketones are blended, the blending ratio of the ketones is, for example, 0.01 parts by mass or more, preferably 1 part by mass or more, and for example, 200 parts by mass or less, preferably 100 parts by mass or less, based on the solid content, per 100 parts by mass of aldehydes.

Examples of the acid catalyst include organic acids and inorganic acids. Examples of the organic acids include carboxylic acid compounds, sulfonic acid compounds, and phosphoric acid compounds. Examples of the carboxylic acid compounds include formic acid, acetic acid, and oxalic acid. Examples of the sulfonic acid compounds include methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, cumenesulfonic acid, dinonylnaphthalene monosulfonic acid, and dinonylnaphthalene disulfonic acid. Examples of the phosphoric acid compounds include phosphoric acid esters. More specifically, examples of the phosphoric acid esters include phosphoric acid esters having an alkyl group having 1 to 18 carbon atoms. Examples of the phosphoric acid compounds include trimethyl phosphate, triethyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, and trioctyl phosphate. Examples of the inorganic acid include phosphoric acid, hydrochloric acid, sulfuric acid, and nitric acid. These acid catalysts can be used alone or in combination of two or more kinds. As the acid catalyst, preferably, an organic acid is used, more preferably, a carboxylic acid compound, and even more preferably, oxalic acid is used.

In the reaction between phenols and aldehydes, the mixing ratio of the aldehydes is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, per 100 parts by mass of the phenols. The mixing ratio of the aldehydes is, for example, 35 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the phenols.

The proportion of the acid catalyst is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, per 100 parts by mass of the phenols. The proportion of the acid catalyst is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, per 100 parts by mass of the phenols.

The timing of adding the acid catalyst is not particularly limited. For example, the acid catalyst may be added to the phenols and/or aldehydes in advance. The acid catalyst may also be added at the same time that the phenols and aldehydes are mixed. Furthermore, the acid catalyst may also be added after the phenols and aldehydes are mixed.

Reaction conditions include atmospheric pressure. The reaction temperature is, for example, 50°C or higher, preferably 80°C or higher. The reaction temperature is, for example, 200°C or lower, preferably 180°C or lower. The reaction time is, for example, 1 hour or longer, preferably 2 hours or longer. The reaction time is, for example, 20 hours or shorter, preferably 15 hours or shorter.

This produces a novolac phenolic resin as a reaction product of the phenols and aldehydes. Commercially available novolac phenolic resins can also be used.

In PEG-modified lignin, polyethylene glycol (PEG) is used to improve the sliding properties, heat resistance and flexural properties.

The number average molecular weight of polyethylene glycol is, for example, 100 or more, preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more. The number average molecular weight of polyethylene glycol is, for example, 1000 or less, preferably 900 or less, more preferably 800 or less, and even more preferably 600 or less. If the number average molecular weight is within the above range, it is possible to achieve both sliding properties, heat resistance, and bending properties. The number average molecular weight can be determined as a polyethylene glycol equivalent molecular weight by a known gel permeation chromatography method.

In PEG-modified lignin, lignin is a polymeric phenolic compound. Lignin is a natural product (natural lignin) and is found in plants in general. Examples of the basic structure of lignin include guaiacyl lignin (G type), syringyl lignin (S type), and p-hydroxyphenyl lignin (H type).

Lignin is extracted industrially from plant materials. Examples of plant materials include lignocellulose. Examples of lignin include soda lignin, sulfite lignin, and kraft lignin. Methods for extracting lignin include the soda process, the sulfite process, the steam explosion method, the solvolysis method, and the kraft process.

Specific examples of lignin include lignin derived from woody plants and lignin derived from herbaceous plants.

Examples of woody plant-derived lignin include coniferous lignin contained in conifers (e.g., cedar, etc.) and broadleaf lignin contained in broadleaf trees. Note that woody plant-derived lignin does not contain an H-type basic skeleton. More specifically, among woody plant-derived lignins, coniferous lignin does not contain an S-type basic skeleton and has a G-type basic skeleton. Furthermore, broadleaf lignin has both a G-type basic skeleton and an S-type basic skeleton.

An example of lignin derived from herbaceous plants is rice lignin, which is contained in plants of the Gramineae family. Examples of plants of the Gramineae family include wheat straw, rice straw, corn, and bamboo. Lignin derived from herbaceous plants has all of the basic skeletons of H-type, G-type, and S-type.

These lignins can be used alone or in combination of two or more kinds. As the lignin, preferably, woody plant-derived lignin that does not contain an H-type basic skeleton is used, more preferably, coniferous lignin that does not contain an S-type basic skeleton and has a G-type basic skeleton is used, and particularly preferably, coniferous lignin derived from Japanese cedar is used. PEG-modified lignin obtained from coniferous lignin derived from Japanese cedar has excellent homogeneity.

PEG-modified lignin is produced, for example, according to the method described in JP 2017-197517 A.

In this method, for example, plant material (lignocellulose), which is the raw material for lignin, is digested using polyethylene glycol.

The digestion method is not particularly limited, but for example, the plant material that is the raw material for lignin, polyethylene glycol, and an inorganic acid (e.g., hydrochloric acid, sulfuric acid, etc.) as an acid catalyst are mixed and reacted.

The blending ratio of polyethylene glycol is, for example, 200 parts by mass or more, preferably 300 parts by mass or more, per 100 parts by mass of the plant material that is the raw material for lignin. The blending ratio of polyethylene glycol is, for example, 1000 parts by mass or less, preferably 600 parts by mass or less, per 100 parts by mass of the plant material that is the raw material for lignin.

The mixing ratio of the inorganic acid (100% conversion) is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more, per 100 parts by mass of polyethylene glycol. The mixing ratio of the inorganic acid (100% conversion) is, for example, 2 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of polyethylene glycol.

Reaction conditions include normal pressure. The reaction temperature is, for example, 120°C or higher, preferably 130°C or higher. The reaction temperature is, for example, 180°C or lower, preferably 150°C or lower. The reaction time is, for example, 60 minutes or longer. The reaction time is, for example, 240 minutes or shorter, preferably 120 minutes or shorter.

After the reaction is completed, an appropriate amount of alkali is added to the reaction solution to adjust the pH. Examples of alkali include ammonia and sodium hydroxide. This allows the PEG-modified lignin to be extracted into the solution. The pH after the adjustment is, for example, 8 or more, preferably 10 or more, more preferably 10.5 or more, and is, for example, 14 or less.

By this method, pulp is obtained as a solid component and PEG-modified lignin is obtained as a solution component.

Then, in this method, the solid components (pulp) are separated from the reaction product by known separation methods such as filtration, pressing, and centrifugation, and the solution components are recovered.

In this method, if necessary, the solid component (pulp) can be washed and the solution (PEG-modified lignin) that is impregnated into the solid component can be recovered.

Then, in this method, an inorganic acid (e.g., hydrochloric acid, sulfuric acid, etc.) is added to adjust the pH to precipitate and cause the PEG-modified lignin to precipitate.

The pH after adjustment is, for example, 1.5 or more, and, for example, 5 or less, preferably 3 or less, and more preferably 2 or less.

This allows the PEG-modified lignin to precipitate. The resulting precipitate can then be collected by a known method, such as filtration, pressing, or centrifugation, to obtain the PEG-modified lignin as a solid content.

The binder (binding agent) contains novolac phenolic resin and PEG-modified lignin. In other words, the binder can be a mixture of novolac phenolic resin and PEG-modified lignin.

The blending ratio of the novolac phenolic resin and the PEG-modified lignin is, on a solids (non-volatile) basis, for example, 10 parts by mass or more, preferably 20 parts by mass or more, of the PEG-modified lignin per 100 parts by mass of the novolac phenolic resin. Also, for example, 300 parts by mass or less, preferably 200 parts by mass or less, of the PEG-modified lignin per 100 parts by mass of the novolac phenolic resin.

If the blending ratio of novolac-type phenolic resin and PEG-modified lignin is within the above range, an excessive increase in viscosity can be suppressed, excellent moldability can be ensured, and various physical properties of the resulting sliding material can be improved.

The kneading method is not particularly limited, and a known kneading machine can be used. Examples of kneading machines include a single-screw extruder, a multi-screw extruder, a roll kneader, a kneader, a Henschel mixer, and a Banbury mixer.

The kneading temperature is 80°C or higher, preferably 90°C or higher, and more preferably 100°C or higher. The kneading temperature is 180°C or lower, preferably 170°C or lower, and more preferably 160°C or lower. The kneading time is, for example, 3 minutes or more, and preferably 5 minutes or more. The kneading time is, for example, 30 minutes or less, and preferably 20 minutes or less.

This results in a binder (binding agent) being obtained as a resin composition containing novolac-type phenolic resin and PEG-modified lignin.

That is, the binder contains a novolac-type phenolic resin and a PEG-modified lignin. Therefore, the binder can improve the sliding properties, heat resistance, and flexural properties.

The binder may also contain a phenolic resin curing agent, if necessary. The phenolic resin curing agent is not particularly limited, and may be any known curing agent. Examples of the phenolic resin curing agent include hexamethylenetetramine, methylolmelamine, and methylolurea. These phenolic resin curing agents may be used alone or in combination of two or more. The blending ratio of the phenolic resin curing agent is appropriately set according to the purpose and application, within a range that does not impair the excellent effects of the present invention.

The binder may further contain additives. Examples of additives include known additives that are added to binders. Examples of additives include fillers, colorants, plasticizers, stabilizers, and release agents. Examples of fillers include wood flour, pulp, and glass fibers. Examples of release agents include metal soaps, more specifically, zinc stearate. These additives may be used alone or in combination of two or more types. The timing of adding the additives is not particularly limited and may be appropriately set depending on the purpose and application. The mixing ratio of the additives may be appropriately set depending on the purpose and application within a range that does not impair the excellent effects of the present invention.

The sliding material may contain other binders as necessary. The other binders are binders other than the above-mentioned resin composition (a mixture of novolac-type phenolic resin and PEG-modified lignin). Examples of the other binders include known thermosetting resins. Examples of the thermosetting resins include melamine resins and epoxy resins. The other binders may be used alone or in combination of two or more types.

When other binders are blended, the blending ratio is appropriately set within a range that does not impair the effects of the present invention. Preferably, no other binders are blended. In other words, the sliding material preferably contains only the above-mentioned resin composition as a binder.

The sliding material preferably contains a lubricant. The lubricant is not particularly limited, and examples thereof include known solid lubricants. Examples of solid lubricants include graphite and molybdenum disulfide. These lubricants can be used alone or in combination of two or more types. A preferred example of the lubricant is graphite.

The average particle size of the lubricant is, for example, 1 μm or more, preferably 5 μm or more. The average particle size of the lubricant is, for example, 1000 μm or less, preferably 500 μm or less.

The sliding material preferably contains a fiber base material. The fiber base material is not particularly limited, but examples thereof include organic fibers, metal fibers, and inorganic fibers. Examples of organic fibers include aromatic polyamide fibers (aramid fibers) and flame-resistant acrylic fibers. Examples of metal fibers include copper fibers and brass fibers. Examples of inorganic fibers include _Al2O3 - _SiO2 ceramic fibers, potassium titanate fibers, biosoluble ceramic fibers, glass fibers, and carbon fibers. These fiber base materials can be used alone or in combination of two or more types. From the viewpoint of slidability, the fiber base material is preferably an inorganic fiber, and more preferably a glass fiber.

The average fiber length of the fiber substrate is, for example, 5 μm or more, preferably 10 μm or more. The average fiber length of the fiber substrate is, for example, 30,000 μm or less, preferably 25,000 μm or less.

In the manufacture of the sliding material, for example, the above-mentioned binder is first mixed and kneaded with the lubricant and the fibrous base material to produce a molding material (composition) for the sliding material.

In the molding material for sliding materials, the total amount of the fiber base material and the lubricant is, for example, 25 parts by mass or more, preferably 50 parts by mass or more, per 100 parts by mass of the binder. Also, the total amount of the fiber base material and the lubricant is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, per 100 parts by mass of the binder.

In addition, the binder content is, for example, more than 30 parts by mass, and preferably more than 40 parts by mass, relative to 100 parts by mass of the total of the binder, lubricant, and fiber base material. In addition, the binder content is, for example, 90 parts by mass or less, and preferably 80 parts by mass or less, relative to 100 parts by mass of the total of the binder, lubricant, and fiber base material.

The content of the fiber base material is, for example, 1 part by mass or more, preferably 5 parts by mass or more, per 100 parts by mass of the total of the binder, lubricant, and fiber base material. The content of the fiber base material is, for example, 65 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the total of the binder, lubricant, and fiber base material.

The content of the lubricant is, for example, 1 part by mass or more, preferably 3 parts by mass or more, per 100 parts by mass of the total of the binder, lubricant, and fiber base material. The content of the lubricant is, for example, 30 parts by mass or less, preferably 25 parts by mass or less, per 100 parts by mass of the total of the binder, lubricant, and fiber base material.

The kneading method is not particularly limited, and a known kneader can be used. Examples of kneaders include a single-screw extruder, a multi-screw extruder, a roll kneader, a kneader, a Henschel mixer, and a Banbury mixer.

The kneading temperature is, for example, 80°C or higher, preferably 90°C or higher, and more preferably 100°C or higher. The kneading temperature is, for example, 180°C or lower, preferably 170°C or lower, and more preferably 160°C or lower. The kneading time is, for example, 3 minutes or higher, and preferably 5 minutes or higher. The kneading time is, for example, 30 minutes or lower, and preferably 20 minutes or lower.

Since this molding material for sliding materials contains a mixture of the above-mentioned novolac-type phenolic resin and PEG-modified lignin as a binder, it is possible to obtain a sliding material that has excellent sliding properties, heat resistance, and flexure properties.

Next, in this method, the above-mentioned molding material for the sliding material is molded by a known method. This results in the sliding material.

As the molding method, a known method is used. More specifically, examples of the molding method include transfer molding and compression molding. The molding conditions are not particularly limited and are set appropriately depending on the purpose and application.

For example, the temperature condition is, for example, 140°C or higher, preferably 150°C or higher. The temperature condition is, for example, 200°C or lower, preferably 180°C or lower. The pressure condition is, for example, 20 MPa or higher, preferably 30 MPa or higher. The pressure condition is, for example, 100 MPa or lower, preferably 80 MPa or lower. The processing time is, for example, 2 minutes or more, preferably 10 minutes or more. The processing time is, for example, 60 minutes or lower, preferably 30 minutes or lower.

In this way, the sliding material is obtained by molding the molding material for the sliding material.

The sliding material may be treated by a known method as necessary. Examples of such treatments include degreasing and primer treatment. The molded sliding material may be after-cured (thermosetting) by a known method.

The processing conditions for the after-cure are not particularly limited, but normal pressure is used. The temperature conditions are, for example, 10 to 100°C higher than the temperature during the above-mentioned molding. The temperature conditions are, for example, 150°C or higher, preferably 160°C or higher. The temperature conditions are, for example, 300°C or lower, preferably 200°C or lower. The processing time is, for example, 1 hour or longer, preferably 2 hours or longer. The processing time is, for example, 10 hours or shorter, preferably 8 hours or shorter. The after-cure can improve the sliding properties and heat resistance.

The sliding material contains a binder, and the binder contains a novolac-type phenolic resin and lignin modified with polyethylene glycol. Therefore, the sliding material has excellent sliding properties and heat resistance, and further has excellent flexural properties.

As a result, the sliding material is suitable for use in, for example, the bearing parts of various rotating devices and the seal parts of sliding devices.

Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass. Note that the specific numerical values of the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit value (a numerical value defined as "equal to or less than") or lower limit value (a numerical value defined as "equal to or more than" or "exceeding") of the corresponding compounding ratio (content ratio), physical property value, parameter, etc. described in the above "Form for carrying out the invention".

Production Example 1 (Mn200-PEG-modified lignin)
Lignin modified with polyethylene glycol having a number average molecular weight of 200 (hereinafter, Mn200-PEG-modified lignin) was produced by the following method.

That is, 230 parts by mass of commercially available polyethylene glycol (PEG200) with a number average molecular weight of 200 and 0.69 parts by mass of sulfuric acid as an acid catalyst (0.3 parts by mass per 100 parts by mass of PEG200) were placed in a reaction vessel and stirred. Next, 46 parts by mass of bone-dried cedar wood flour were placed in the reaction vessel, and the temperature was raised to 140°C under normal pressure, and the mixture was reacted for 90 minutes while stirring. Next, the reaction vessel was cooled, and after confirming that the temperature was 40°C or less, 280 parts by mass of sodium hydroxide (0.2 mol/L) was placed in and stirred for 30 minutes. Next, the obtained solid component (pulp) was removed by a filter press, and the solution component was collected. Next, sulfuric acid was added to the obtained solution component, and the pH was adjusted to 2.0. This resulted in a suspension of Mn200-PEG-modified lignin. Then, the Mn200-PEG-modified lignin was collected by centrifugation.

Production Example 2 (Mn400-PEG-modified lignin)
An Mn400-PEG modified lignin was obtained in the same manner as in Production Example 1, except that polyethylene glycol having a number average molecular weight of 400 (hereinafter, Mn400-PEG) was used instead of polyethylene glycol having a number average molecular weight of 200.

Production Example 3 (Mn600-PEG modified lignin)
An Mn600-PEG modified lignin was obtained in the same manner as in Production Example 1, except that polyethylene glycol having a number average molecular weight of 600 (hereinafter, Mn600-PEG) was used instead of polyethylene glycol having a number average molecular weight of 200.

Production Example 4 (Kraft Lignin)
Kraft lignin (manufactured by SIGMA-ALDRICH, derived from woody plants, aliphatic hydroxyl group content 4.4% by mass) was prepared.

Production Example 5 (Phenol-modified Kraft Lignin)
328.9 parts by mass of phenol was placed in a flask and heated to about 50° C. to liquefy the phenol, and then 100 parts by mass of kraft lignin (manufactured by SIGMA-ALDRICH, derived from woody plants, aliphatic hydroxyl group content 4.4% by mass) was added.

Next, 3 parts by mass of 98% concentrated sulfuric acid (acid catalyst) was added, and the mixture was then reacted at 130°C for 2.5 hours. This resulted in the modification of the kraft lignin with phenol.

The resulting product was then repeatedly washed with 1,000 parts by weight of water until the pH reached 6 to 7, and then the phenol-modified kraft lignin (phenol-modified lignin) was extracted by suction filtration using filter paper (Advantec No. 101).

Production Example 6 (Lignin Acetate)
100 parts by mass of corn stover was mixed with 1000 parts by mass of 95% acetic acid and 3 parts by mass of sulfuric acid, and reacted under reflux for 4 hours. After the reaction, the pulp was removed by filtration, and the pulp waste liquid was recovered. Next, the acetic acid in the pulp waste liquid was removed using a rotary evaporator, and the liquid was concentrated to 1/10 in volume, and then 10 times the amount (by mass) of the concentrated liquid was added and filtered to obtain lignin modified with acetic acid (acetic acid lignin).

Production Example 7 (Phenol-modified acetic acid lignin)
Acetic acid lignin was used instead of kraft lignin. The rest of the procedure was the same as in Production Example 5. As a result, acetic acid lignin modified with phenol (phenol-modified acetic acid lignin) was obtained.

Examples 1 to 9 and Comparative Examples 1 to 6
Novolac-type phenolic resin (CP506 manufactured by Asahi Organic Chemicals Co., Ltd.), lignin of Production Examples 1 to 5, hexamethylenetetramine (phenolic resin hardener, manufactured by Lignite Co., Ltd.), and zinc stearate (release agent, manufactured by Wako Pure Chemical Industries, Ltd.) were kneaded in the ratios shown in Tables 1 and 2. Thus, a binder was obtained.

Then, the binder, glass fiber (CS3SK-406, manufactured by Nitto Boseki), and graphite (SGP-100, manufactured by SEC Carbon) were mixed in the ratios shown in Tables 1 and 2. The mixture was then kneaded for 5 minutes at 100°C using two heated rolls. This produced a molding material for sliding members.

Then, the molding material for the sliding material was compression molded at 170°C for 15 minutes. This resulted in obtaining a disk-shaped test piece with a diameter of 100 mm as the sliding material. The obtained sliding material was then thermally cured (after-cured) at 180°C for 4 hours.

<<Evaluation>>
The sliding materials obtained in each of the Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Tables 3 and 4.

(1) Glass transition temperature: The solid dynamic viscoelasticity was measured using Rheogel-E4000 (manufactured by UBM Co., Ltd.) (frequency 1 Hz, heating rate 2° C./min). The peak temperature of the obtained tan δ curve was determined as the glass transition temperature (Tg).

(2) Friction Coefficient The friction coefficient (static friction coefficient and kinetic friction coefficient) was determined using a surface property tester (Shinto Scientific, HEIDON-14S/D) in accordance with ASTM D 1894. The various conditions for determining the friction coefficient and the dimensions of the test specimen used are shown below.
Test piece: 100 mm diameter, 3 mm thick disc test piece Mating material: 19 mm diameter cylinder Mating material: S45C
Test speed: 100 mm/min. The sliding material is required to have a static friction coefficient of 0.15 or less. The sliding material is also required to have a dynamic friction coefficient of 0.10 or less.

(3) Abrasion test (Taber type)
The amount of wear was measured according to JIS-K7204 (1999 edition), and the amount of wear reduction from the initial sample mass was calculated in mass %. The conditions of the wear test and the dimensions of the test pieces used are shown below.
(Wear test conditions)
Load: 10N
Rotation speed: 60 rpm
Wear wheel: H-18
Rotation speed: 1000 rpm, 2000 rpm (test piece)
A disk test piece with a diameter of 100 mm and a thickness of about 3 mm. The sliding material is required to have a mass loss rate of 2.5% or less in a 1000-revolution abrasion test. The sliding material is also required to have a mass loss rate of 4.0% or less in a 2000-revolution abrasion test.

(4) Maximum elongation In accordance with JIS K6911 (1995), a three-point bending test was performed at a crosshead speed of 3 mm/min and a span of 100 mm to measure the maximum elongation. The maximum elongation is the strain (maximum elongation) when the sample is bent until it breaks, and was calculated by the following formula:

Maximum point elongation (ε) = [6T/L ² ] × ΔL
(T: thickness of sample, L: distance between supporting points, ΔL: bending deflection amount)

Claims (1)

A sliding material containing a binder,
The sliding material, wherein the binder contains a novolac type phenolic resin and lignin modified with polyethylene glycol.