WO2018179821A1 - Sliding material - Google Patents

Abstract

This sliding material includes a binder. The binder includes a reaction product of a lignin, a phenol, and an aldehyde.

Description

Sliding material

The present invention relates to a sliding material, and more particularly to a sliding material for ensuring slidability.

Conventionally, sliding materials have been used for bearings of various rotating devices and seals of sliding devices in order to ensure slidability and reduce damage due to friction. The sliding material is usually manufactured as a resin molded product containing a lubricant such as carbon fiber and a binder such as a phenol resin.

Specifically, for example, a phenol resin-carbon fiber composite material obtained by filling a carbon fiber subjected to air oxidation treatment and amine compound treatment in a phenol resin base material, and a molded product obtained by heat press molding the same Has been proposed (see Patent Document 1).

JP-A-6-136142

On the other hand, sliding materials are required to further improve various physical properties such as friction characteristics (wear resistance, low friction coefficient) and heat resistance.

An object of the present invention is to provide a sliding material having excellent friction characteristics and heat resistance.

The present invention [1] is a sliding material containing a binder, and the binder contains a sliding material containing a reaction product of lignin, phenols and aldehydes.

This invention [2] contains the sliding material as described in said [1] whose said lignin is a craft lignin.

The present invention [3] includes the sliding material according to the above [1] or [2], wherein the lignin is a herbaceous plant-derived lignin.

Since the sliding material of the present invention contains a binder containing a reaction product of lignin, phenols, and aldehydes, it has excellent friction characteristics and heat resistance.

The sliding material of the present invention contains a binder (binder).

The binder (binder) contains a reaction product of lignin, phenols and aldehydes, and preferably comprises a reaction product of lignin, phenols and aldehydes.

Lignin is a high molecular phenolic compound having a basic skeleton such as guaiacyl lignin (G type), syringyl lignin (S type), p-hydroxyphenyl lignin (H type) and the like.

More specifically, lignin is classified according to, for example, the type of plant used as a raw material, and specific examples include woody plant-derived lignin and herbaceous plant-derived lignin.

Examples of woody plant-derived lignin include coniferous lignin contained in conifers (eg, cedar), for example, broadleaf lignin contained in broadleaf trees. Such woody plant-derived lignin does not contain lignin having H-type basic skeleton, for example, conifer lignin has G-type basic skeleton, and hardwood lignin has G-type and S-type basic skeleton. Yes.

Examples of the herbaceous plant-derived lignin include, for example, rice-based lignin contained in Gramineae plants, and more specifically, wheat straw lignin contained in wheat straw, rice straw lignin contained in rice straw, and corn. Examples include corn lignin and bamboo lignin contained in bamboo. Such herbaceous plant-derived lignin has all of H-type, G-type and S-type as the basic skeleton.

These lignins can be used alone or in combination of two or more.

The lignin is preferably a herbaceous plant-derived lignin, more preferably a herbaceous plant-derived lignin derived from straw, or a herbaceous plant-derived lignin derived from corn.

Further, as lignin, from the viewpoint of reactivity, it is preferable to contain an H-type basic skeleton in a proportion of 3% by mass or more, more preferably 9% by mass or more, and still more preferably 14% by mass or more. It is done.

Such lignin is contained in waste liquid (black liquor) discharged when pulp is produced from a plant by a known method such as an alkali method (soda method), a sulfurous acid method, or a kraft method. More specifically, the waste liquid (black liquor) discharged in the alkali method (soda method) contains alkali lignin (soda lignin), and the waste liquid (black liquor) discharged in the sulfurous acid method is sulfite. The waste liquid (black liquor) containing lignin and discharged in the kraft process contains craft lignin.

In addition to the above, examples of lignin include acid-modified lignin obtained by modifying lignin with an acid (such as carboxylic acid such as acetic acid), explosive lignin obtained by treating a plant with a blasting method, and the like.

The lignin is preferably craft lignin from the viewpoints of frictional properties and heat resistance.

Also, lignin preferably has an aliphatic hydroxyl group in the molecule.

An aliphatic hydroxyl group is a hydroxyl group that is not directly bonded to an aromatic ring but directly bonded to an aliphatic hydrocarbon, and is distinguished from a hydroxyl group directly bonded to an aromatic ring (aromatic hydroxyl group (phenolic hydroxyl group)).

The content ratio of the aliphatic hydroxyl group of lignin is, for example, 0.5% by mass or more, preferably 3.0% by mass or more, for example, 7.0% by mass or less, preferably, based on the total amount of lignin. It is 5.5 mass% or less.

If the content ratio of the aliphatic hydroxyl group of lignin is in the above range, the friction characteristics and heat resistance can be improved.

In addition, the measuring method of an aliphatic hydroxyl group is based on the Example mentioned later.

Phenols are phenols and derivatives thereof (phenol-modified products) such as phenol, and further, for example, o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol. , P-nonylphenol, bifunctional phenol derivatives such as 2,4- or 2,6-xylenol, for example, trifunctional phenol derivatives such as m-cresol, resorcinol, 3,5-xylenol, such as bisphenol A, dihydroxy And tetrafunctional phenol derivatives such as diphenylmethane. Examples of phenol derivatives include halogenated phenols substituted with halogen such as chlorine and bromine. These phenols can be used alone or in combination of two or more. When a phenol derivative (phenol-modified product) is used, the timing at which the phenol is modified is not particularly limited, and may be any of before, after and after the reaction of lignin, phenols and aldehydes.

Phenols are preferably phenol.

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

Preferred examples of aldehydes include formaldehyde and paraformaldehyde.

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

Also, ketones can be blended with aldehydes.

Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, acetophenone, diphenyl ketone, and the like. These ketones can be used alone or in combination of two or more.

When the 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 with respect to 100 parts by mass of the aldehydes based on the solid content. 200 parts by mass or less, preferably 100 parts by mass or less.

In order to react lignin, phenols, and aldehydes (and ketones blended if necessary (hereinafter the same)), the above components (lignin, phenols, and aldehydes) are blended and heated.

In this reaction, the mixing ratio of the phenols is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, more preferably 100 parts by mass or more, for example, 1000 parts by mass with respect to 100 parts by mass of lignin. Hereinafter, it is preferably 500 parts by mass or less, and more preferably 350 parts by mass or less.

The blending ratio of aldehydes is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, for example, 35 parts by mass or less, preferably 30 parts by mass or less, relative to 100 parts by mass of phenols. is there. The blending ratio of aldehydes is, for example, 1.5 parts by mass or more, preferably 3 parts by mass or more, for example, 350 parts by mass or less, preferably 300 parts by mass or less, with respect to 100 parts by mass of lignin. It is.

If the blending ratio of each component is within the above range, various physical properties such as friction characteristics can be improved.

In this reaction, an acid catalyst is added. That is, each of the above components reacts under an acid catalyst.

Examples of the acid catalyst include organic acids and inorganic acids.

Examples of the organic acid include sulfonic acid compounds such as methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, cumenesulfonic acid, dinonylnaphthalene monosulfonic acid, dinonylnaphthalenedisulfonic acid, for example, trimethyl phosphate, Examples thereof include phosphate esters having an alkyl group having 1 to 18 carbon atoms such as triethyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, trioctyl phosphate, and the like, for example, formic acid, acetic acid, oxalic acid and the like.

Examples of inorganic acids include phosphoric acid, hydrochloric acid, sulfuric acid, and nitric acid.

These acid catalysts can be used alone or in combination of two or more.

The acid catalyst is preferably an organic acid, more preferably oxalic acid.

The mixing ratio of the acid catalyst is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, for example, 10 parts by mass or less, preferably 100 parts by mass with respect to 100 parts by mass of phenols. 5 parts by mass or less.

The timing of addition of the acid catalyst is not particularly limited, and may be added in advance to at least one of lignin, phenols, and aldehydes, and added at the same time when lignin, phenols, and aldehydes are blended. Further, it may be added after blending lignin, phenols and aldehydes.

As reaction conditions, under atmospheric pressure, the reaction temperature is, for example, 50 ° C. or higher, preferably 80 ° C. or higher, for example, 200 ° C. or lower, preferably 180 ° C. or lower. The reaction time is, for example, 1 hour or more, preferably 2 hours or more, for example, 20 hours or less, preferably 15 hours or less.

Thereby, a binder (binder) is obtained as a resin composition containing a reaction product of lignin, phenols and aldehydes (specifically, a novolac-type phenol resin modified with lignin).

More specifically, a novolac-type phenol resin is obtained by the reaction of phenols and aldehydes in the presence of an acid catalyst, and the novolac-type phenol resin is modified with lignin.

That is, a resin composition (binder) containing a novolac type phenol resin modified with lignin is obtained.

According to the binder (binder) thus obtained, a sliding material having excellent friction characteristics and heat resistance can be obtained.

In addition, in the reaction of lignin, phenols and aldehydes, as described above, the above-mentioned components can be combined and reacted, but the above-mentioned components can be combined and reacted sequentially. More specifically, for example, first, lignin and phenols can be reacted, and then the obtained reaction product can be reacted with aldehydes.

Specifically, in the sequential reaction, first, lignin and phenols are reacted to prepare a lignin-phenol composition containing a reaction product of lignin and phenols, and then the lignin-phenol composition and aldehyde React with a kind.

In the reaction of lignin and phenols, the phenols are blended in an excess equivalent amount with respect to lignin. Specifically, the blending ratio of phenols is, for example, 30 parts by mass or more, preferably 100 parts by mass of lignin. 50 parts by mass or more, for example, 1000 parts by mass or less, preferably 500 parts by mass or less.

In this reaction, the above acid catalyst is added.

The mixing ratio of the acid catalyst is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, for example, 10 parts by mass or less, preferably 5 parts by mass with respect to 100 parts by mass of the phenols. It is as follows.

The timing of addition of the acid catalyst is not particularly limited, and may be added in advance to at least one of lignin and phenols, or may be added simultaneously with the blending of lignin and phenols. It may be added after blending lignin and phenols.

As reaction conditions, under atmospheric pressure, the reaction temperature is, for example, 60 ° C. or higher, preferably 80 ° C. or higher, for example, 250 ° C. or lower, preferably 200 ° C. or lower. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 10 hours or less, preferably 5 hours or less.

This reaction modifies lignin with phenols. Specifically, the aliphatic hydroxyl group in the lignin molecule is substituted with phenols.

In the above reaction, excess phenols remain as unreacted components. Therefore, the lignin-phenol composition obtained by the above reaction contains a reaction product of lignin and phenols (lignin modified with phenols) and free phenols.

Next, in this method, the lignin-phenol composition obtained as described above (that is, lignin modified with phenols and free phenols) is reacted with aldehydes.

In this reaction, the blending ratio of aldehydes is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, with respect to 100 parts by mass of phenols (phenols used as a raw material in the above reaction). , 35 parts by mass or less, preferably 30 parts by mass or less.

In this reaction, the above acid catalyst can be added at an appropriate ratio, if necessary.

As reaction conditions, under atmospheric pressure, the reaction temperature is, for example, 50 ° C. or higher, preferably 80 ° C. or higher, for example, 200 ° C. or lower, preferably 180 ° C. or lower. The reaction time is, for example, 1 hour or more, preferably 2 hours or more, for example, 20 hours or less, preferably 15 hours or less.

As a result, the above lignin-phenol composition reacts with aldehydes to obtain a novolak-type phenol resin modified with lignin (lignin-modified novolak-type phenol resin), and the resin containing the lignin-modified novolak-type phenol resin. A binder is obtained as a composition.

In the production of a lignin-modified novolac type phenol resin, unreacted raw materials (unreacted phenols, etc.) and acid catalyst can be removed by a known method such as distillation, if necessary.

According to the binder thus obtained, a sliding material having excellent friction characteristics and heat resistance can be obtained.

Further, the binder (resin composition) can contain a phenol resin curing agent, if necessary.

The phenol resin curing agent is not particularly limited, and a known curing agent can be used. Specifically, for example, hexamethylenetetramine, methylolmelamine, methylolurea, phenol novolac and the like can be mentioned.

These phenolic resin curing agents can be used alone or in combination of two or more.

The blending ratio of the phenol resin curing agent is appropriately set according to the purpose and application.

In addition, the binder can further contain an additive.

As additives, known additives added to the binder, for example, fillers (wood flour, pulp, glass fibers, etc.), colorants, plasticizers, stabilizers, mold release agents (metal soaps such as zinc stearate) Etc.).

These additives can be used alone or in combination of two or more. The content of the additive is appropriately set according to the purpose and application within a range that does not impair the excellent effects of the present invention.

Note that the timing of addition of the additive is not particularly limited, and is appropriately set according to the purpose and application.

Further, the sliding material can contain other binders (binders excluding the above reaction products) as required in addition to the above binders.

Examples of other binders include known thermosetting resins such as melamine resins and epoxy resins.

Other binders can be used alone or in combination of two or more.

When other binders are blended, the blending ratio is appropriately set within a range not impairing the effects of the present invention. Preferably, an embodiment in which no other binder is blended (that is, an embodiment in which the sliding material contains only the above reaction product as a binder) is included.

Also, the sliding material preferably contains a lubricant.

The lubricant is not particularly limited, and examples thereof include known solid lubricants such as graphite and molybdenum disulfide.

These lubricants can be used alone or in combination of two or more.

As the lubricant, graphite (graphite) is preferable.

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

Also, the sliding material preferably contains a fiber base material.

Although it does not restrict | limit especially as a fiber base material, For example, organic fibers, such as aromatic polyamide fiber (aramid fiber) and a flame-resistant acrylic fiber, For example, metal fibers, such as copper fiber and a brass fiber, For example, potassium titanate fiber, Examples thereof include inorganic fibers such as Al ₂ O ₃ —SiO ₂ ceramic fibers, biosoluble ceramic fibers, glass fibers, and carbon fibers.

These fiber base materials can be used alone or in combination of two or more.

From the viewpoint of slidability, the fiber base material is preferably inorganic fiber, more preferably glass fiber.

The average fiber length of the fiber substrate is, for example, 5 μm or more, preferably 10 μm or more, for example, 30000 μm or less, preferably 25000 μm or less.

Specifically, the sliding material is obtained by first blending and kneading the binder, the lubricant, and the fiber base material to produce a molding material (composition) for the sliding material, and then obtaining the sliding material. The sliding material molding material can be obtained by molding by a known method.

In the production of the molding material for sliding material, the mixing ratio of each component is such that the total amount of the fiber base material and the lubricant is, for example, 25 parts by mass or more, preferably 50 parts per 100 parts by mass of the binder. For example, 200 parts by mass or less, preferably 150 parts by mass or less.

More specifically, the binder is, for example, more than 30 parts by weight, preferably more than 40 parts by weight, for example, 90 parts by weight or less, with respect to 100 parts by weight of the total amount of the binder, lubricant, and fiber substrate. The amount is preferably 80 parts by mass or less.

Further, the fiber substrate is, for example, 1 part by mass or more, preferably 5 parts by mass or more, for example, 65 parts by mass or less, preferably 100 parts by mass with respect to the total amount of the binder, the lubricant, and the fiber substrate. 30 parts by mass or less.

The lubricant is, for example, 1 part by mass or more, preferably 3 parts by mass or more, for example, 30 parts by mass or less, preferably 100 parts by mass with respect to the total amount of the binder, the lubricant, and the fiber substrate. 25 parts by mass or less.

The kneading method is not particularly limited, and for example, a known kneader such as a single-screw extruder, a multi-screw extruder, a roll kneader, a kneader, Henschel mixer, or a Banbury mixer can be used.

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

Since such a molding material for a sliding material contains the above reaction product (resin composition) as a binder, a sliding material having excellent friction characteristics and heat resistance can be obtained.

As a method for molding the above-mentioned molding material for sliding material, for example, the molding material for sliding material is molded by a known thermosetting resin molding method such as transfer molding or compression molding. The molding conditions are not particularly limited, and are appropriately set according to the purpose and application.

For example, the processing conditions in the molding are not particularly limited, but the temperature conditions are, for example, 140 ° C. or higher, preferably 150 ° C. or higher, for example, 200 ° C. or lower, preferably 180 ° C. or lower. The pressure condition is, for example, 20 MPa or more, preferably 30 MPa or more, for example, 100 MPa or less, preferably 80 MPa or less. The treatment time is, for example, 2 minutes or longer, preferably 10 minutes or longer, for example, 60 minutes or shorter, preferably 30 minutes or shorter.

Thus, the sliding material is obtained by molding the molding material for the sliding material.

Further, the sliding material can be treated by a known method such as degreasing treatment or primer treatment, if necessary, and the molded sliding material can be treated with a known method after-curing (heat treatment). Curing treatment).

The treatment conditions in the after-curing are not particularly limited, but under atmospheric pressure, the temperature conditions are preferably 10 to 100 ° C. higher than the temperature at the time of molding, specifically, for example, 150 ° C. or more, preferably It is 160 degreeC or more, for example, 300 degrees C or less, Preferably, it is 200 degrees C or less. The treatment time is, for example, 1 hour or more, preferably 2 hours or more, for example, 10 hours or less, preferably 8 hours or less.

Thus, after-curing the sliding material, it is possible to further improve the friction characteristics and heat resistance.

And since such a sliding material contains the binder containing the reaction product of lignin, phenols, and aldehydes, it is excellent in friction characteristics and heat resistance.

Therefore, the sliding material is preferably used in, for example, bearing parts of various rotating devices, sealing parts of sliding devices, and the like.

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, “part” and “%” are based on mass unless otherwise specified. In addition, specific numerical values such as a blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and a blending ratio corresponding to them ( Substituting the upper limit value (numerical value defined as “less than” or “less than”) or the lower limit value (number defined as “greater than” or “exceeded”) such as content ratio), physical property values, parameters, etc. be able to.

<< Content ratio of aliphatic hydroxyl group >>
The content ratio of the aliphatic hydroxyl group to the total amount of lignin was measured by the following method.

That is, first, 5 mL each of pyridine and acetic anhydride was added to 500 mg of lignin, and allowed to stand at room temperature for 24 hours to acetylate the hydroxyl group. Subsequently, pyridine and acetic anhydride were removed with an evaporator while adding toluene.

Thereafter, 5 mg of acetylated lignin was dissolved in 1 g of a solvent, and proton NMR measurement was performed under the following conditions to determine the amount of protons of the acetyl group appearing at about 1.9 ppm. On the other hand, proton NMR measurement was also performed on lignin that was not acetylated under the same conditions, and the amount of protons in the acetyl group was quantified.

Then, from the peak intensity at about 1.9 ppm of acetylated lignin, the peak intensity at about 1.9 ppm of non-acetylated lignin was subtracted to obtain the peak amount due to acetylation. This was made into the amount of aliphatic hydroxyl groups.
Apparatus: Bruker Ltd. AscendTM 400 NMR apparatus _{solvent: D 2 O37.5g + NaOD12.5g + DSS} -d 6 (3- ( trimethylsilyl) -1-propane _{-1,1,2,2,3,3-d 6} - sulfonate, sodium Standard substance) 25mg
Measurement frequency: 400MHz
Measurement temperature: 25 ° C
Number of scans: 128 Preparation Example 1 (acetic acid-modified lignin)
100 parts by mass of corn stover was mixed with 1000 parts by mass of 95% by mass acetic acid and 3 parts by mass of sulfuric acid, and reacted for 4 hours under reflux. After the reaction, the pulp was removed by filtration, and the pulp waste liquid was recovered. Next, after removing acetic acid in the pulp waste liquid using a rotary evaporator and concentrating until the volume becomes 1/10, 10 times the amount of the concentrated liquid (mass basis) is added and filtered, Acetic acid-modified lignin was obtained as a solid content.

The obtained acetic acid-modified lignin was dissolved in ethyl acetate and separated into a filtrate and a residue by filtration. Acetic acid-modified lignin contained in the obtained filtrate was used as a soluble component (soluble acetic acid-modified lignin).

Further, the residue was washed with distilled water and filtered again, and the residue obtained was used as an insoluble component (insoluble acetic acid lignin).

Preparation Example 2 (Craft Lignin)
Kraft lignin (manufactured by SIGMA-ALDRICH, derived from woody plant, aliphatic hydroxyl group content 4.4 mass%) was prepared.

Preparation Example 3 (Soda Lignin)
After neutralizing the alkali digested pulp waste liquor (black liquor) of straw, it filtered and the lignin (alkali lignin, soda lignin) was obtained as solid content. The aliphatic hydroxyl group content of lignin was 3.1% by mass.

<< Manufacture of novolac-type phenolic resin >>
Synthesis Example 1 (Lignin used: Acetic acid-modified lignin (sequential reaction))
Put 493.5 parts by mass of phenol in a flask and heat to about 50 ° C. to liquefy the phenol, and then add 150 parts by mass of the soluble component (soluble acetic acid-modified lignin) of acetic acid-modified lignin obtained in Preparation Example 1. Added.

Next, 7.62 parts by mass of oxalic acid (acid catalyst) was added, and then reacted at 130 ° C. for 2.5 hours. This modified the acetic acid-modified lignin with phenol.

Then, it cooled to 80 degreeC, 117.3 mass parts of paraformaldehyde was added, and it was made to react at 95 degreeC for 2.5 hours. Next, the temperature was raised to 110 ° C. at 0.5 ° C./min and reacted at 110 ° C. for 1.5 hours. Next, the temperature was raised to 120 ° C. at 0.5 ° C./min and reacted at 120 ° C. for 2 hours.

After the reaction, 2300 parts by mass of water was added, and after stirring vigorously, the mixture was allowed to stand, and water was removed by decantation to remove oxalic acid and phenol. Furthermore, the residual phenol was removed by distillation under reduced pressure under conditions of 150 ° C. and 0.08 MPa while adding water as appropriate. The vacuum distillation was repeated until the phenol residual ratio became 1% or less.

Thereby, a novolac type phenol resin modified with phenol-modified acetic acid lignin was obtained.

Synthesis Example 2 (Lignin used: Acetic acid-modified lignin (collective reaction))
Put 493.5 parts by mass of phenol in a flask and heat to about 50 ° C. to liquefy the phenol, and then add 150 parts by mass of the soluble component (soluble acetic acid-modified lignin) of acetic acid-modified lignin obtained in Preparation Example 1. Added.

Next, 7.62 parts by mass of oxalic acid (acid catalyst) and 117.3 parts by mass of paraformaldehyde were added and reacted at 95 ° C. for 2.5 hours. Next, the temperature was raised to 110 ° C. at 0.5 ° C./min and reacted at 110 ° C. for 1.5 hours. Next, the temperature was raised to 120 ° C. at 0.5 ° C./min and reacted at 120 ° C. for 2 hours.

After the reaction, 2300 parts by mass of water was added, and after stirring vigorously, the mixture was allowed to stand, and water was removed by decantation to remove oxalic acid and phenol. Furthermore, the residual phenol was removed by distillation under reduced pressure under conditions of 150 ° C. and 0.08 MPa while adding water as appropriate. The vacuum distillation was repeated until the phenol residual ratio became 1% or less.

Thereby, a novolac type phenol resin modified with acetic acid-modified lignin was obtained.

Synthesis Example 3 (Lignin used: Acetic acid-modified lignin (sequential reaction))
A novolak type phenol resin modified with phenol-modified acetic acid lignin was obtained in the same manner as in Synthesis Example 1 except that the formulation shown in Table 1 was changed.

Synthesis Example 4 (Lignin used: Acetic acid-modified lignin (collective reaction))
A novolak-type phenol resin modified with lignin acetate was obtained in the same manner as in Synthesis Example 2 except that the formulation shown in Table 1 was changed.

Synthesis Example 5 (Lignin used: Acetic acid-modified lignin (sequential reaction))
A novolak type phenol resin modified with phenol-modified acetic acid lignin was obtained in the same manner as in Synthesis Example 1 except that the formulation shown in Table 1 was changed.

Synthesis Example 6 (Lignin used: Acetic acid-modified lignin (collective reaction))
A novolak-type phenol resin modified with lignin acetate was obtained in the same manner as in Synthesis Example 2 except that the formulation shown in Table 1 was changed.

Synthesis Example 7 (Lignin used: Kraft lignin (sequential reaction))
Instead of acetic acid-modified lignin, novolak-type phenol modified with kraft lignin modified with phenol in the same manner as in Synthesis Example 1 except that 150 parts by mass of kraft lignin of Preparation Example 2 was used. A resin was obtained.

Synthesis Example 8 (Lignin used: Kraft lignin (collective reaction))
A novolak-type phenol resin modified with kraft lignin was obtained in the same manner as in Synthesis Example 2, except that 150 parts by mass of kraft lignin of Preparation Example 2 was used instead of acetic acid-modified lignin.

Synthesis Example 9 (Lignin used: Soda lignin (sequential reaction))
A novolac phenol modified with phenol-modified soda lignin in the same manner as in Synthesis Example 1 except that 150 parts by mass of soda lignin of Preparation Example 3 was used instead of acetic acid-modified lignin. A resin was obtained.

Synthesis Example 10 (Lignin used: Soda lignin (collective reaction))
A novolak-type phenol resin modified with soda lignin was obtained in the same manner as in Synthesis Example 2, except that 150 parts by mass of soda lignin of Preparation Example 3 was used instead of acetic acid-modified lignin.

Synthesis example 11 (use lignin: none)
2068 parts by mass of phenol, 31.82 parts by mass of oxalic acid (acid catalyst) and 430.43 parts by mass of paraformaldehyde were placed in a flask and reacted at 95 ° C. for 2.5 hours. Next, the temperature was raised to 110 ° C. at 0.5 ° C./min and reacted at 110 ° C. for 1.5 hours. Next, the temperature was raised to 120 ° C. at 0.5 ° C./min and reacted at 120 ° C. for 2 hours.

After the reaction, 2800 parts by mass of water was added, and after stirring vigorously, the mixture was allowed to stand, and water was removed by decantation to remove oxalic acid and phenol. Furthermore, the residual phenol was removed by distillation under reduced pressure under conditions of 150 ° C. and 0.08 MPa while adding water as appropriate. The vacuum distillation was repeated until the phenol residual ratio became 1% or less.

Thereby, a novolac type phenol resin not modified by lignin was obtained.

<< Manufacture of sliding material >>
Example 1
100 parts (450 g) of the novolak-type phenol resin obtained in Synthesis Example 1, 12 parts (54 g) of hexamethylenetetramine (manufactured by lignite) as a phenol resin curing agent, and zinc stearate (Wako Pure Chemical Industries) as a release agent 1 part (4.5 g) manufactured by Kogyo Co., Ltd. was kneaded to obtain a resin composition.

Next, 50 parts of the obtained resin composition, 25 parts of glass fiber (CS3SK-406, manufactured by Nittobo) and 25 parts of graphite (SGP-100, manufactured by SEC carbon) were blended in order, and two hot rolls were used. The mixture was kneaded at 100 ° C. for 5 minutes to obtain a molding material for sliding material.

Thereafter, the obtained molding material for sliding material was compression molded at 170 ° C. for 15 minutes to obtain a disk-shaped test piece of 100 mmφ as the sliding material.

Examples 2 to 10 and Comparative Example 1
A sliding material was obtained in the same manner as in Example 1 except that the formulation was changed to the formulation shown in Table 2.

<< Evaluation >>
The sliding materials obtained in each Example and each Comparative Example were evaluated by the following methods. The results are shown in Tables 2-3.
(1) Friction coefficient In accordance with ASTM D1894, a friction coefficient (static friction coefficient and dynamic friction coefficient) was determined using a surface property tester (Shinto Kagaku HEIDON-14S / D). Various conditions for obtaining the friction coefficient and dimensions of the test piece used are shown below.
Test piece: Disc test piece with a diameter of 100 mm and a thickness of about 3 mm Mating material: 19 mm diameter cylinder Mating material: S45C
Test speed: 100 mm / min (2) Wear test (Taber type)
The amount of wear was measured in accordance with JIS-K7204 (1999 edition), and the amount of wear was calculated in mass% to indicate how much the mass was reduced from the mass of the first sample. The conditions of the wear test and the dimensions of the test piece used are shown below.
(Wear test conditions)
Load: 10N
Rotation speed: 60rpm
Wear wheel: H-18
Number of revolutions: 1000 revolutions (test piece)
Disc test piece having a diameter of 100 mm and a thickness of about 3 mm (3) Dynamic viscoelasticity test Rheogel-E4000 (manufactured by UBM) was used to measure the solid dynamic viscoelasticity (frequency 1 Hz, heating rate 2 ° C.). / Min). And the peak temperature of the obtained tan-delta curve was calculated | required as glass transition temperature (Tg).

(Discussion)
From Tables 2 to 3, it was confirmed that friction characteristics and heat resistance can be improved by using a reaction product of lignin, phenols and aldehydes.

For example, when Example 2 and Example 6 are compared with Comparative Example 1, when using the batch reaction product of each of the above components compared to the case where the above reaction product is not used, friction is maintained while maintaining wear resistance. It was confirmed that the coefficient could be reduced and the heat resistance could be improved.

Moreover, when Example 1 and Example 2 are compared, compared with the case where the batch reaction product of each of the above components is used, the wear resistance can be improved when the reaction product of each of the above components is used, and the friction coefficient is increased. It was confirmed that the heat resistance could be reduced and the heat resistance could be improved.

Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be interpreted in a limited manner. Variations of the present invention that are apparent to one of ordinary skill in the art are within the scope of the following claims.

The sliding material of the present invention is used in bearing parts of various rotating equipment, seal parts of sliding equipment, and the like.

Claims (3)

A sliding material containing a binder,
The binder is
Lignin,
Phenols,
A sliding material comprising a reaction product with aldehydes. The sliding material according to claim 1, wherein the lignin is craft lignin. The sliding material according to claim 1, wherein the lignin is a herbaceous plant-derived lignin.