JP2019151829A - Composite material for sliding and sliding member equipped with the same - Google Patents

Abstract

To provide a composite material for sliding in which a substrate and an impregnated resin are excellently integrated, swell of water is suppressed, and which has good mechanical strength as a sliding application without deteriorating property of a phenol resin, and a sliding member equipped with the same at low cost.SOLUTION: There are provided a composite material for sliding having a substrate and a phenol resin, in which the substrate is an unwoven fabric of a polyphenylene sulfide fiber, and the phenol resin is impregnated into the unwoven fabric, and a sliding member having the composite material for sliding arranged on a sliding surface.SELECTED DRAWING: None

Description

  The present invention relates to a sliding composite material and a sliding member provided with the same.

  As this type of composite material, for example, a laminate in which a fiber base material is impregnated with various resins to form a prepreg, and this prepreg is laminated and cured is known. Of these, laminates of cotton fabrics and other fabrics impregnated with phenolic resin are excellent in flame retardancy, friction and wear characteristics during lubrication, mechanical strength, and can be manufactured at relatively low cost. Widely used as another sliding member. However, in the case of a composite material in which, for example, a cotton cloth is impregnated with a phenol resin, since the cotton cloth and the phenol resin have good affinity with water, the water absorption is highly swollen, resulting in a large dimensional change. Therefore, it was used under wet conditions and was not suitable for applications that require high dimensional accuracy.

  As an improvement measure, it has been proposed to use a fabric using fibers having low water absorption as a base material (see, for example, Patent Documents 1 to 3).

  In Patent Document 1, a double yarn formed by aligning at least two pieces of a single twisted yarn of a fluororesin fiber and a single twisted yarn of a polyphenylene sulfide (PPS) fiber and applying a twist opposite to the single twisted direction of the single twisted yarn is used as a warp. And a sliding base material impregnated with a resol type phenolic resin in which a tetrafluoroethylene (PTFE) resin is dispersed and contained in a reinforcing base material formed of a woven fabric formed as a weft, the reinforcing base material is a plain woven fabric, It is described that the density of the plain woven fabric is warp yarns of 36 to 44 yarns / 2.54 cm and weft yarns of 36 to 44 yarns / 2.54 cm. And, by having such a configuration, it is said that a sliding surface material having good adhesion between the base material and the phenol resin, excellent frictional wear characteristics, low water swellability and high dimensional accuracy can be obtained. .

  In Patent Document 2, phenols containing 50 to 100 mol% of bisphenol A and formaldehydes are synthesized using amines as catalysts, the number average molecular weight Mn by gel permeation chromatography measurement is 500 to 1000, and weight A fiber for a sliding member obtained by impregnating a polyphenylene sulfide (PPS) fiber woven fabric with a resol type phenol resin having a dispersion degree Mw / Mn of 2.5 to 15 as a ratio of the average molecular weight Mw and the number average molecular weight Mn. A reinforced resin composition is described. As a result, the adhesion between the PPS fiber woven fabric and the phenol resin is good, and the swelling resistance to water is good.

  Patent Document 3 discloses a multiple woven fabric including a sliding fabric and a base fabric that may be impregnated with a resin, wherein the sliding fabric is a fabric including polytetrafluoroethylene fiber A, and the base fabric is It is a woven fabric composed of fibers B having a creep rate of 20% lower than that of polytetrafluoroethylene fibers in a standard state, and polytetrafluoroethylene fibers A are composed of tetrafluoroethylene in 90 mol% or more. A wear-resistant multi-woven fabric is described which is made of a copolymer, the fiber B is a polyphenylene sulfide fiber, and the sliding fabric and the base fabric are intertwined with each other by warp and / or weft yarns. As a result, the wear resistance is high, and it is said that the slidability can be exhibited for a long time even under an environment under a higher load than before.

Japanese Patent No. 5859183 Japanese Patent No. 5249726 Japanese Patent No. 598806

  According to the invention described in the above-mentioned patent document, it is possible to some extent to obtain a composite material in which the adhesion between the base material and the impregnating resin is appropriately secured and the swelling of water is suppressed. However, in the invention described in the cited document 1, it is necessary to use a specific woven fabric formed from specific yarns using fluororesin fibers and PPS fibers, and to impregnate the base material with a PTFE resin. There is room for improvement in terms of mechanical strength and cost. In the invention described in the cited document 2, since a woven fabric of PPS fibers is used, the phenol resin is difficult to be impregnated, and there is room for improvement in terms of wear resistance and cost. In the invention described in the cited document 3, it is necessary to use a multiple fabric including a sliding fabric of PTFE fiber and a base fabric of PPS fiber which may be impregnated with resin, which is improved in terms of mechanical strength and cost. There is room for.

  Therefore, the problem of the present invention is that the base material and the impregnating resin are well integrated, the swelling of water is suppressed, and the mechanical strength is good for sliding applications without impairing the characteristics of the phenolic resin. It is to provide a sliding composite material and a sliding member including the same at low cost.

  As a result of intensive studies, the inventor of the present invention uses a non-woven fabric of PPS fibers as a base material, so that the phenol resin penetrates well without being restricted by the fiber bundle of PPS fibers, and the swelling of water is suppressed, It has been found that a sliding composite material having good mechanical strength as a sliding application and a sliding member provided therewith can be provided at low cost without impairing the characteristics of the phenolic resin. The gist of the present invention is as follows.

  A first aspect of the present invention is a sliding composite material comprising a base material and a phenol resin, wherein the base material is a polyphenylene sulfide fiber nonwoven fabric, and the nonwoven fabric is impregnated with the phenol resin. About.

In an embodiment of the present invention, the phenolic resin may be a novolac type phenolic resin. Moreover, the base material may have a reinforcing layer. The density of the nonwoven fabric may be 250 to 650 g / m ² , and in that case, the tensile strength of the nonwoven fabric may be 15 N / mm ² or more. Moreover, the nonwoven fabric may be impregnated with at least one selected from molybdenum disulfide, graphite, carbon black, and carbon fiber. Moreover, a base material may be provided with two or more nonwoven fabrics, and in this case, these nonwoven fabrics may be laminated | stacked in the thickness direction.

  The second of the present invention relates to a sliding member in which the above-mentioned sliding composite material is provided on a sliding surface.

  According to the present invention, the base material and the impregnating resin are satisfactorily integrated, the swelling of water is suppressed, and good mechanical strength as a sliding application is obtained without impairing the characteristics of the phenol resin. It is possible to provide the sliding composite material and the sliding member including the same at low cost.

It is the figure which showed the time-dependent change of the wear height of each test piece when the pin-on-disk test was done using the test piece of Examples 1, 2 and Comparative Examples 1, 2.

  Embodiments of the present invention will be described below.

  The embodiment of the sliding composite material according to the present invention includes a base material and a phenol resin. The substrate is a non-woven fabric of polyphenylene sulfide (PPS) fibers. The nonwoven fabric is impregnated with a phenol resin.

The PPS fiber is excellent in heat resistance, chemical resistance, and hydrolysis resistance. Further, the water absorption of the PPS fiber is 0.1% by weight or less. Therefore, swelling of water into the composite material can be suppressed by using PPS fibers. Moreover, PPS itself is said to have impact resistance and mechanical strength comparable to general-purpose engineering plastics, and PPS fibers may have excellent mechanical strength as well. PPS fibers having such properties, the polymer constituent units _{- (C 6 H 4 -S)} - which is a synthetic fiber made of a polymer whose main structural unit. The structural unit represented by — (C ₆ H ₄ —S) — may be a p-phenylene unit or an m-phenylene unit. As another structural unit, for _{example, - (C 6 H 4 -O} -C 6 H 4 -S) -, - (C 6 H 4 -SO 2 -C 6 H 4 -S) -, - ( C ₆ H ₄ —CO—C ₆ H ₄ —S) —, — (C ₆ H ₃ (CH ₃ ) —S) —, — (C ₆ H ₂ (CH ₃ ) ₂ —S) — and the like. . The polymer having the structural unit-(C ₆ H ₄ -S)-as a structural unit preferably has a linear structure, but may partially have a crosslinked structure. Representative examples of these PPS polymers include, for example, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers, block copolymers, and mixtures thereof. Preferred PPS polymers, as the main structural units of the _{polymer, - (C 6 H 4 -S} ) - a represented by p- phenylene units, preferably 70 mol% or more, more preferably containing at least 90 mol% Is.

  The fiber length of the PPS fiber is preferably 2 to 100 mm from the viewpoint of obtaining better strength of the nonwoven fabric. From the same viewpoint, the fineness of the single fiber is preferably 0.1 to 15 denier.

  Examples of commercially available products of PPS fibers include, for example, Torcon (registered trademark) manufactured by Toray Industries, Inc. and Procon (registered trademark) manufactured by Toyobo Co., Ltd.

  The nonwoven fabric which comprises a base material can use what was prescribed | regulated to JISL0222, for example. For example, in a web in which fibers are laminated and spread into a sheet shape, fibers are appropriately bonded by the following (a) to (e) to form a cloth; (a) Chemical by an adhesive Bonding, (b) fusion by heating, (c) mechanical entanglement (needle punch) with a hooked needle, (d) entanglement by jetting high-pressure water flow, (e) web stitching (stitch bond). Among these, the nonwoven fabric by a needle punch is preferable from a viewpoint of performing better integration with a phenol resin. The nonwoven fabric by needle punch has a so-called felt appearance. In the case of non-woven fabric by needle punch, compared to other non-woven fabrics and woven fabrics, the phenol resin is more easily impregnated, and the fibers are intertwined with each other at a pinpoint, so that the contact area between the PPS fiber and the phenol resin is increased. Conceivable. As a result, a dense structure with few voids can be obtained, and better characteristics can be obtained.

The density (weight per unit area) of the nonwoven fabric is preferably 250 to 650 g / m ² from the viewpoint of obtaining better strength of the nonwoven fabric and from the viewpoint of better integration with the phenol resin. If the density is lowered within this range, the impregnation amount of the phenol resin is relatively increased and the strength tends to be increased. When the density is increased within this range, the wear resistance tends to increase. Therefore, in applications where wear resistance is more important, the density can be set to, for example, 450 to 650 g / m ² . Moreover, it is preferable that the nonwoven fabric has a tensile strength of 15 N / mm ² or more because the sliding sealing material is manufactured more stably and more inexpensively. Moreover, if the tensile strength is in such a range, the upper limit is not particularly limited. It can set suitably according to the structure of the nonwoven fabric of a PPS fiber, or the nonwoven fabric which combined the reinforcement layer mentioned later. The upper limit of the non-woven fabric of PPS fibers can be, for example, 50 N / mm ² or less because it is generally easy to obtain at low cost. The nonwoven fabric preferably has a thickness of less than 3 mm and a weight per unit area of 650 g / m ² or less because a prepreg in which phenol resin and the like are uniformly dispersed is obtained by the impregnation operation.

  The phenolic resin is generally excellent in heat resistance and flame retardancy and has good mechanical properties. Therefore, by impregnating the PPS fiber base material with a phenol resin and compositing it, a composite material having excellent flame retardancy and mechanical strength and suppressing water absorption can be obtained. The phenol resin may be a reaction product of phenols and aldehydes, and known ones can be adopted.

  The phenols are not particularly limited, and examples thereof include alkylphenols (cresol, xylenol, etc.), polyhydric phenols (resorcinol, etc.), phenylphenol, aminophenol, and the like. Moreover, aldehydes are not specifically limited, Formaldehyde, paraformaldehyde, acetaldehyde, a furfural, etc. are mentioned.

  As a phenol resin at the time of impregnating a nonwoven fabric, either a resol type phenol resin or a novolac type phenol resin may be used, and it can be appropriately selected according to the use. From the viewpoint of better integration with the non-woven fabric of PPS fiber, a novolac type phenol resin is preferable. The resol type phenol resin is, for example, a product obtained by reacting phenols and aldehydes in an excess of aldehydes and in the presence of a base catalyst. The novolak type phenol resin is obtained by, for example, reacting phenols and aldehydes in an excess of phenols and under an acid catalyst. Commercially available resol type phenol resins and novolac type phenol resins can be used. For example, Sumilite Resin (registered trademark) PR series manufactured by Sumitomo Bakelite Co., Ltd. may be mentioned.

  By curing the resol type phenolic resin and the novolac type phenolic resin, a member for the sliding surface of the sliding member can be obtained. The resol type phenolic resin can be cured by heating or acid addition. The novolak type phenol resin can be cured by heating in the presence of a crosslinking agent. Examples of the crosslinking agent for curing the novolak type phenol resin include hexamethylenetetramine. Moreover, the conditions at the time of hardening can be suitably selected according to the kind etc. of a resole type phenol resin and a novolak type phenol resin.

  The nonwoven fabric may be impregnated with other additives in addition to the phenol resin. Examples of such additives include lubricants, vibration damping agents, reinforcing agents, heat resistance agents, flame retardants, weathering agents, and the like.

  Examples of the lubricant include graphite, molybdenum disulfide, carbon black, carbon fiber, hexagonal boron nitride, and talc.

  Examples of the vibration damper include graphite, carbon fiber, potassium titanate, mica and the like.

  Examples of the reinforcing agent include carbon fiber, wollastonite, potassium titanate, zonotlite, aramid fiber, glass fiber, talc, mica and the like.

  Examples of the heat-resistant agent include heat-insulating agents such as glass balloons, silica balloons, and shirasu balloons, thermal conductivity imparting agents such as alumina, aluminum nitride, and boron nitride, and heat ray radiation such as alumina, magnesium oxide, hydrotalcite, and charcoal powder. Agents and the like.

  Examples of the flame retardant include hydroxide flame retardants such as aluminum hydroxide and magnesium hydroxide, halogen flame retardants, phosphorus flame retardants, antimony flame retardants, zinc borate, red phosphorus, zinc carbonate, hydrotalcite And dosonite.

  Examples of the weathering agent include titanium oxide and zinc oxide.

  Among the additives as described above, at least one selected from molybdenum disulfide, graphite, carbon black, and carbon fiber from the viewpoint of exerting the function while suppressing the aggressiveness of the sliding member against the counterpart material. Is preferred.

  The base material may have a reinforcing layer. Examples of such a reinforcing layer include a cloth such as a scrim cloth or a filter cloth (filter cloth) provided between non-woven fabrics of PPS fibers. Such a fabric is preferably formed of, for example, PPS fibers. The reinforcing layer can be provided, for example, adjacent to the inner layer of the nonwoven fabric or at least one surface. When forming the laminated body which laminated | stacked the prepreg, the reinforcement layer may be provided in all the nonwoven fabrics according to a use etc., and may be provided in one part nonwoven fabric. For example, the reinforcing layer can be integrated with the nonwoven fabric when the nonwoven fabric is formed.

  The number of non-woven fabrics in the substrate can be appropriately determined according to the application and the like, and may be one or plural. When the thickness of the sliding composite material is increased, it is preferable that a plurality of nonwoven fabrics are laminated in the thickness direction of the base material.

  The ratio (A / B) of the base material (A) and the phenol resin (B) is not particularly limited, and is, for example, 30/70 to 55/45 on a weight basis. Moreover, there is no limitation in the content in the case of using the above-mentioned additive, and it can determine suitably according to the kind. For example, the addition amount of the lubricant may be more than 0 parts by weight and 20 parts by weight or less with respect to 100 parts by weight of the phenol resin. Further, for example, the reinforcing agent, the heat-resistant agent, the flame retardant, and the weather resistance imparting agent can be more than 0 parts by weight and 6 parts by weight or less with respect to 100 parts by weight of the phenol resin. In the case of using a plurality of additives, the upper limit thereof can be generally 50 parts by weight or less with respect to 100 parts by weight of the phenol resin. 30 parts by weight or less is preferable with respect to 100 parts by weight of phenol resin, and 25 parts by weight or less is more preferable because it is easy to disperse uniformly in the phenol resin of the sliding composite material.

  The sliding composite material can be manufactured by a known method. For example, first, a non-woven fabric of PPS fibers is brought into contact with a varnish containing a phenol resin. Examples of the method of bringing the non-woven fabric of PPS fiber into contact with the varnish containing the phenol resin include a method of immersing the non-woven fabric of PPS fiber in the varnish, a method of applying the varnish, and a method of spraying the varnish. In this case, the non-woven fabric may be brought into contact with the varnish one by one. For example, the non-woven fabric is continuously brought into contact with the varnish while moving the long non-woven fabric in the long axis direction using an apparatus such as an uncoiler. Also good. In consideration of mass productivity, it is preferable that a long nonwoven fabric is continuously brought into contact with the varnish. In this case, a more stable treatment can be performed when the tensile strength of the nonwoven fabric is equal to or greater than the above lower limit. Next, for example, the nonwoven fabric is impregnated with the varnish by applying a surface pressure with a gap roll or the like. At the same time, excess varnish is removed as necessary. Thereafter, the nonwoven fabric impregnated with the varnish is heated to remove the solvent contained in the varnish and partially cure the phenol resin. Thereby, the prepreg of the nonwoven fabric impregnated with the phenol resin is formed. This prepreg is an example of an embodiment of the sliding composite material of the present invention.

  In the case of a resol type phenolic resin, the varnish includes a resol type phenolic resin, an acid added as necessary, an additive added as necessary, and a solvent. In the case of a novolak type phenol resin, it contains a novolak type phenol resin, a crosslinking agent, an additive added as necessary, and a solvent. A conventionally well-known thing can be used for a solvent.

  By heating and pressurizing the prepreg to further cure the phenol resin, a sliding surface member constituting the sliding surface of the sliding member is obtained. When forming a sliding surface member in which a plurality of non-woven fabrics are stacked, the non-woven fabrics are stacked in the thickness direction and laminated to obtain a laminate in which the non-woven fabrics are integrated. Such a sliding surface member is also an example of an embodiment of the sliding composite material of the present invention.

  Using a prepreg, a sliding surface member having a predetermined shape can be formed by a known method. For example, in the case of a flat plate shape, the prepreg is arranged in a flat plate shape and obtained by heating and pressing. In the case of a cylindrical shape, the prepreg is obtained by heating and pressurizing while winding it around a core having a desired outer diameter. Further, when a desired outer surface shape is formed, it is obtained by placing a small piece of a prepreg on the surface of a mold having a surface shape corresponding to the outer surface shape and heating and pressing. Moreover, after heating and pressurizing a prepreg, it can also cut and process into a desired shape.

  Thus, the composite material obtained by heating and pressing the prepreg can be used as a sliding surface member provided on the sliding surface of the sliding member. Examples of the sliding member include a scratch-proof member that requires sliding of the steel line, a marine marine application and a bearing for various devices, a liner, and the like. Among these, since a dimensional change can be suppressed even when in contact with water, it is particularly suitable as a water-lubricating bearing used in ships, water supply / drainage pumps, and the like. Moreover, since a general phenol resin and a nonwoven fabric of PPS fiber can be used, a sliding composite material and a sliding member can be provided at low cost. Moreover, the PPS fiber is merely impregnated with a non-woven fabric of PPS fiber, and the PPS fiber is excellent in heat resistance. Therefore, the flame retardant property of the phenol resin is not impaired, and it has good mechanical strength.

  Hereinafter, embodiments of the present invention will be described in more detail based on examples.

Example 1
A varnish containing 46% by weight of a novolac type phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., Sumilite Resin (registered trademark) PR-50252), 4% by weight of a crosslinking agent hexamine, and 50% by weight of a solvent (methanol) was prepared. After dipping a nonwoven fabric of PPS fibers (Toray Industries, Torcon (registered trademark) RF55, needle punched nonwoven fabric, density: 550 g / m ² , thickness: 1.4 mm, tensile strength: 40 N / mm ² ) in the varnish, Was passed through squeezing rolls to impregnate the varnish into the nonwoven fabric. Then, it was dried at 100 ° C. for 60 minutes to obtain a prepreg. In the prepreg, the weight ratio of the PPS fiber nonwoven fabric to the phenol resin was 45/55.

  After 22 layers of the prepreg were laminated in the thickness direction, the film was heated and pressurized at 180 ° C. and 5 MPa for 60 minutes to obtain a sliding surface member.

(Example 2)
As a non-woven fabric of PPS fiber, instead of Toray Industries, Inc., Torcon (registered trademark) RF55, Fujiko Co., Ltd., RFSL30, density: 300 g / m ² , thickness: 0.5 mm, tensile strength: 20 N / mm ² is used. Except that, a prepreg and a sliding surface member were obtained in the same manner as in Example 1.

(Comparative Example 1)
Implemented except for using PPS fiber plain weave (Toray Industries, TFRC-1, density: 380 g / m ² , thickness: 0.6 mm, tensile strength: 15 N / mm ² ) instead of PPS fiber non-woven fabric A prepreg and a sliding surface member were obtained in the same manner as in Example 1.

(Comparative Example 2)
Example 1 except that cotton fabric (manufactured by Toko Kosen Co., Ltd., No. 11 canvas, density: 340 g / m ² , thickness: 0.6 mm, tensile strength: 30 N / mm ² ) was used in place of the non-woven fabric of PPS fiber. Similarly, a prepreg and a sliding surface member were obtained.

  Test pieces were prepared from the sliding surface members obtained in Examples 1 and 2 and Comparative Examples 1 and 2, and the following evaluation tests were performed. The evaluation results are shown in Table 1. Moreover, the change with time of wear height is shown in FIG.

(Evaluation)
<Specific gravity>
Specific gravity was measured by a method based on JIS K7112.

<Hardness>
Rockwell hardness was measured in the thickness direction of the sliding surface member by a method based on JIS K7202.

<Bending characteristics>
A bending test was performed in the thickness direction of the sliding surface member by a method based on JIS K6911.

<Compression characteristics>
A compression test was performed in the thickness direction of the sliding surface member by a method based on JIS K6911.

<Dimensional stability>
The dimensional change rate in the thickness direction of the sliding surface member was calculated after the test piece of 50 mm × 50 mm × thickness 10 mm was left in water kept at 20 ° C. for 28 days.

<Friction and wear characteristics>
A φ5 mm test piece was prepared, and a pin-on-disk test was performed under the conditions shown in Table 2 using a pin-on-disk type friction and wear tester (manufactured by Starlight Industry Co., Ltd., auto pin disk APD-101). . The test was performed twice. In the test piece of φ5 mm, the central axis direction was the thickness direction of the sliding surface member. In Table 1, the specific wear amount means the calculated wear height per hour when the elapsed time from the start of the test is 30 to 40 hours. The test results are shown in Table 1 and FIG.

  As shown in Table 1, by using PPS fiber nonwoven fabric, in Examples 1 and 2, the hardness, bending strength, and compressive strength are equal to or higher than those of Comparative Examples 1 and 2, and water absorption is suppressed. Thus, it can be seen that the dimensional change rate is extremely low. It can also be seen that the specific wear amount can be greatly reduced. As shown in FIG. 1, it can be seen that the wear height is significantly lower in Examples 1 and 2 than in Comparative Examples 1 and 2 over the test time.

Claims (7)

A sliding composite material comprising a base material and a phenol resin,
A sliding composite material, wherein the base material is a non-woven fabric of polyphenylene sulfide fiber, and the non-woven fabric is impregnated with the phenol resin.   The sliding composite material according to claim 1, wherein the phenol resin is a novolac type phenol resin.   The sliding composite material according to claim 1, wherein the substrate has a reinforcing layer. 4. The sliding composite material according to claim 1, wherein the density of the nonwoven fabric is 250 to 650 g / m ² , and the tensile strength of the nonwoven fabric is 15 N / mm ² or more.   5. The sliding composite material according to claim 1, wherein the nonwoven fabric contains at least one selected from molybdenum disulfide, graphite, carbon black, and carbon fiber.   The sliding composite material according to any one of claims 1 to 5, wherein the base material includes a plurality of nonwoven fabrics, and the nonwoven fabrics are laminated in the thickness direction thereof. A sliding member provided with the sliding composite material according to any one of claims 1 to 6 on a sliding surface.

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