JP2015199859A - Polyamideimide resin composition for sliding member and sliding member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamideimide resin for a sliding member which is excellent in solubility in a solvent, is capable of forming a flexible and rigid lubrication film and has a reduced water absorption rate while making use of heat resistance (glass transition temperature) or mechanical properties (tensile strength and tear strength) or the like inherent in a polyamideimide resin.SOLUTION: There is provided a polyamideimide resin for a sliding member containing 10 to 90 mol% of a constitutional unit represented by the following formula (1) in the polyamideimide resin. (where, Rrepresents an alkyl group having 1 to 5 carbon atoms or -SO-; Rand Rmay be the same or different and each represents hydrogen, a halogen atom, an aryl group or an alkyl group having 1 to 3 carbon atoms, provided that when Ris SO-, Rand Rare not present; and Rrepresents an aryl group which may have a substituent.)

Description

  The present invention relates to a novel polyamideimide resin composition for sliding members and a sliding member using the same.

Polyamideimide resins are generally widely used as coating agents for various substrates because they are generally excellent in heat resistance, chemical resistance, and solvent resistance. For example, Patent Document 1 discloses a composition for a lubricating coating in which a solid lubricant is blended with a polyamideimide resin. However, in order to reduce the friction coefficient, it is necessary to use a large amount of the solid lubricant. It was. When the blending amount of the solid lubricant increases, there is a problem that the coating becomes soft and wear amount under a high load increases. Furthermore, since the polyamideimide resin has a high water absorption, there is a problem that the wearability at the time of water absorption is lowered.

Therefore, in order to reduce the water absorption and friction coefficient of the polyamideimide resin itself, Patent Document 2 and Patent Document 3 propose a polyamideimide resin modified or copolymerized with silicone. However, although silicone is expensive and the coefficient of friction decreases when silicone is copolymerized, the polyamide-imide resin and silicone are inherently poorly compatible, making the sliding coating brittle and dissolving in solvents. As a result, the pot life of the coating material is reduced, making it difficult to work for a long time.

Further, Patent Document 4 proposes a polyamideimide resin composition for a sliding member into which o-tolidine having a rigid structure is introduced in order to improve wear resistance, friction characteristics and seizure resistance without copolymerizing silicone. ing. However, there is a problem that the sliding coating is hard and brittle, the solubility in a solvent is lowered, the pot life of the paint is lowered, and the work for a long time becomes difficult.

  On the other hand, in recent years, automobiles have increasingly demanded low fuel consumption and energy saving, and air conditioner compressors also have wear resistance, low friction coefficient, sliding stability in high humidity atmosphere and their effects. Durability is required.

JP 05-59387 A Japanese Patent Laid-Open No. 08-92528 JP 2006-16561 A JP 2003-30660 A

  The present invention forms heat-resistant (glass transition temperature) and mechanical properties (wear resistance), which are the original characteristics of polyamide-imide resin, and forms a flexible and tough lubricating film with excellent solubility in organic solvents. It is an object of the present invention to provide a polyamideimide resin composition for a sliding member which is possible and has a reduced water absorption rate.

In view of the situation as described above, the present inventors diligently, researched, and studied, and as a result, introduced the specific structure into the polyamide-imide resin to overcome the above problems and arrive at the present invention.
That is, the present invention is as follows.

A polyamideimide resin composition for a sliding member, comprising a polyamideimide resin containing 10 to 90 mol% of a structural unit represented by the following general formula (1) in a polyamideimide resin, and a solid lubricant.
(In the general formula (1), R ₁ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ —. R ₂ and R ₃ may be the same or different, and may be hydrogen, halogen atom, aryl group or Represents an alkyl group having 1 to 3 carbon atoms, provided that when R ₁ is —SO ₂ —, R ₄ represents an aryl group which may have a substituent.

The polyamideimide resin includes a structural unit derived from trimellitic anhydride, a structural unit derived from a polyvalent carboxylic dianhydride represented by the following general formula (2), and a structural unit derived from diisocyanate or diamine, And when the sum total of the structural unit derived from the acid component in a polyamide-imide resin is 100 mol%, the structural unit derived from the polyhydric carboxylic dianhydride shown by General formula (2) is 10-90 mol%. It is preferable.
(In the general formula (2), R ₅ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ —. R ₆ and R ₇ may be the same or different, and may be a hydrogen atom, a halogen atom, an aryl group or Represents an alkyl group having 1 to 3 carbon atoms, provided that R ₅ is —SO ₂ —.

  The polyvalent carboxylic dianhydride represented by the general formula (2) is 4,4 ′-(4,4′-isopropylidenediphenoxy) bisphthalic dianhydride, 4,4 ′-(4,4 ′. -Hexafluoropropylidenediphenoxy) bisphthalic dianhydride, 4,4 '-(4,4'-diphenylpropylidenediphenoxy) bisphthalic dianhydride, 4,4'-(4,4'-ethylenedi It is preferably at least one compound selected from the group consisting of phenoxy) bisphthalic dianhydride and 4,4 ′-(4,4′-sulfonyldiphenoxy) bisphthalic dianhydride.

  The solid lubricant is preferably at least one selected from the group consisting of metal sulfides, fluorine compounds and graphite.

  The fluorine compound includes polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride and trichlorotrifluoro It is preferable that it is 1 or more types selected from the group which consists of ethylene.

  The structural unit derived from diisocyanate or diamine is preferably a structural unit derived from aromatic diisocyanate or aromatic diamine.

  The polyamideimide resin composition preferably further contains an antiwear agent.

  A lubricating coating containing the polyamideimide resin composition.

  A sliding member using the polyamideimide resin composition.

  The polyamideimide resin composition for a sliding member of the present invention has a low friction and wear resistance that is stable even in a high humidity atmosphere for a long time because the polyamideimide resin itself is excellent in solubility in organic solvents and has low water absorption. It is useful for sliding members such as automobile engine pistons and air conditioner compressors.

  Below, the polyamide-imide resin composition for sliding members used in the present invention will be described.

<Polyamideimide resin>
First, the polyamideimide resin used in the present invention will be described. The polyamideimide resin used in the present invention contains 10 to 90 mol% of the structural unit represented by the general formula (1) when the total structural unit in the polyamideimide resin is 100 mol%. . By containing the structural unit of the general formula (1), a flexible and tough film is formed without impairing the inherent heat resistance (glass transition temperature) and wear resistance of the polyamide-imide resin, and water absorption and hygroscopicity are reduced. And flame retardancy is improved. Furthermore, the polymerization can be performed not only with an amide solvent such as N-methyl-2-pyrrolidone or N, N-dimethylacetamide but also with a low hygroscopic solvent such as γ-butyrolactone.

In General Formula (1), R ₁ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ — (sulfone). The alkyl group having 1 to 5 carbon atoms may be linear or branched, and the preferred carbon number is 2 or more, more preferably 3 or more, and preferably 4 or less. R ₂ and R ₃ each independently represents a hydrogen atom, a halogen atom, an aryl group, or an alkyl group having 1 to 3 carbon atoms. However, when R ₁ is sulfone, R ₂ and R ₃ are not present. The halogen atom is not particularly limited as long as it is fluorine, chlorine, bromine or iodine. When R ₂ and R ₃ are a plurality of halogen atoms, each may be one kind of halogen atom, and two or more kinds of halogen atoms It may be an atom. Industrially, it is preferably one type of halogen atom, and more preferably, both R ₂ and R ₃ are fluorine. The aryl group is not particularly limited, but a phenyl group which may have a substituent or a naphthyl group which may have a substituent is preferable, and a phenyl group is more preferable. The alkyl group having 1 to 3 carbon atoms may be linear or branched, and the preferred carbon number is 2 or more.

Preferable R ₁ is not particularly limited, and is a methylene group or sulfone, and preferable R ₂ and R ₃ are not particularly limited, but are hydrogen, a methyl group, a trifluoromethyl group, a benzyl group, or a phenyl group. A preferred embodiment obtained from R ₁ , R ₂ and R ₃ is not particularly limited, but is an isopropyl group, a hexafluoroisopropyl group, a diphenylisopropyl group, a diphenylmethylene group or an ethylene group, and more preferably an isopropyl group.

In general formula (1), R ₄ represents an aryl group which may have a substituent. The aryl group which may have a substituent is not particularly limited, but is preferably a phenyl group, a benzyl group, a tolyl group, a xylyl group or a naphthyl group, and more preferably a phenyl group.

  The structural unit represented by the general formula (1) in the polyamideimide resin used in the present invention is preferably 10 mol% or more, more preferably 15 mol% or more, and 20 mol% or more. Is more preferable. Moreover, it is preferable that it is 90 mol% or less, It is more preferable that it is 85 mol% or less, It is further more preferable that it is 80 mol% or less. If the amount is too small, the water absorption rate is large. If the amount is too large, the solvent solubility may be insufficient.

  It is also preferable to further contain a structural unit represented by the general formula (3). When the structural unit represented by the general formula (3) is contained, it is preferably 10 mol% or more, more preferably 15 mol% or more, and more preferably 20 mol% or more in the polyamideimide resin. Is more preferable. Moreover, it is preferable that it is 90 mol% or less, It is more preferable that it is 85 mol% or less, It is further more preferable that it is 80 mol% or less.

In general formula (3), R ₄ has the same meaning as described above.

The polyamideimide resin used in the present invention is derived from a trimellitic anhydride-derived structural unit, a polycarboxylic acid dianhydride-derived structural unit represented by the following general formula (2), and a diisocyanate or diamine-derived resin. It is preferable that a structural unit is included.
In General Formula (2), R ₅ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ — (sulfone). The alkyl group having 1 to 5 carbon atoms may be linear or branched, and the preferred carbon number is 2 or more, more preferably 3 or more, and preferably 4 or less. R ₆ and R ₇ each independently represent hydrogen, a halogen atom, an aryl group, or an alkyl group having 1 to 3 carbon atoms. However, when R ₅ is sulfone, R ₆ and R ₇ are not present. The halogen atom is not particularly limited as long as it is fluorine, chlorine, bromine or iodine. When R ₆ and R ₇ are a plurality of halogen atoms, each of them may be one type of halogen atom, or two or more types of halogens. It may be an atom. Industrially, it is preferably one type of halogen atom, and more preferably, both R ₆ and R ₇ are fluorine. The aryl group is not particularly limited, but a phenyl group which may have a substituent or a naphthyl group which may have a substituent is preferable, and a phenyl group is more preferable. The alkyl group having 1 to 3 carbon atoms may be linear or branched, and the preferred carbon number is 2 or more.

Preferable R ₅ is not particularly limited, and is a methylene group or sulfone, and preferable R ₆ and R ₇ are not particularly limited, but are hydrogen, a methyl group, a trifluoromethyl group, a benzyl group, or a phenyl group. A preferred embodiment obtained from R ₅ , R ₆ and R ₇ is not particularly limited, but is an isopropyl group, a hexafluoroisopropyl group, a diphenylisopropyl group, a diphenylmethylene group or an ethylene group, and more preferably an isopropyl group.

<Acid component of polyamideimide resin>
In the present invention, it is preferable that a part of the acid component contains a structural unit derived from trimellitic anhydride and a structural unit derived from the polyvalent carboxylic dianhydride represented by the general formula (2), more preferably It is copolymerized with the polyamide-imide resin. By introducing a structural unit derived from the polyvalent carboxylic acid dianhydride represented by the general formula (2) in an appropriate amount range, a flexible and tough film can be formed without impairing the inherent heat resistance and wear resistance of the polyamideimide resin. The water absorption and hygroscopicity are reduced and flame retardancy is improved. Furthermore, the polymerization can be performed not only with an amide solvent such as N-methyl-2-pyrrolidone or N, N-dimethylacetamide but also with a low hygroscopic solvent such as γ-butyrolactone. The reason is that the polyvalent carboxylic acid dianhydride represented by the general formula (2) has a structure with excellent flexibility, a relatively large molecular weight, and is an acid anhydride. This is thought to be because the amount of binding decreases.

  The copolymerization amount of trimellitic anhydride is preferably 10 to 90 mol%, more preferably 20 to 80 mol%, still more preferably 40 to 80 mol% in the total acid component. If this copolymerization amount is less than 10 mol%, there may be a problem in solubility such as the polymerization solution becomes cloudy as the polymerization proceeds, and conversely if it exceeds 90 mol%, the heat resistance will decrease. In some cases, the effect of improving flexibility, toughness, low water absorption and flame retardancy is insufficient.

  The copolymerization amount of the polyvalent carboxylic acid dianhydride represented by the general formula (2) is preferably 10 to 90 mol%, more preferably 20 to 80 mol%, still more preferably 30 to 30 mol% in the total acid component. 70 mol%. When this copolymerization amount is less than 10 mol%, the improvement effect of flexibility, toughness, low water absorption and flame retardancy is insufficient, and conversely, when it exceeds 90 mol%, the heat resistance decreases. As the polymerization proceeds, there may be a problem in solubility such as the polymerization solution becoming cloudy.

  The molar ratio of trimellitic anhydride and the polyvalent carboxylic dianhydride represented by the general formula (2) is preferably in the range of 20/80 to 80/20.

  Although it does not specifically limit as polyhydric carboxylic acid dianhydride shown by General formula (2), 4,4 '-(4,4'-isopropylidenediphenoxy) bisphthalic dianhydride, 4,4 specifically '-(4,4'-hexafluoroisopropylidenediphenoxy) bisphthalic dianhydride, 4,4'-(4,4'-diphenylisopropylidenediphenoxy) bisphthalic dianhydride, 4,4 '-( 4,4′-Ethylenediphenoxy) bisphthalic dianhydride, 4,4 ′-(4,4′-sulfonyldiphenoxy) bisphthalic dianhydride, and the like. Among these, low water absorption and solubility To 4,4 ′-(4,4′-isopropylidenediphenoxy) bisphthalic dianhydride (hereinafter also referred to as BISDA).

  In the present invention, in addition to trimellitic anhydride and the polyvalent carboxylic dianhydride represented by the general formula (2) as an acid component, the following polyvalent carboxylic acids or their anhydrides are impaired in the effect of the present invention. It can be used in a range that does not exist.

  Trifunctional or higher aromatic polyvalent carboxylic acids such as pyromellitic acid, ethylene glycol bis trimellitate, propylene glycol bis trimellitate, 1,4-butanediol bis trimellitate, polyethylene glycol bis trimellitate, etc. 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5, 8-naphthalenetetracarboxylic acid, 2,3,5,6-pyridinetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 4 , 4′-oxydiphthalic acid, 1,1,1,3,3,3-hexafluoro-2- -Bis (2,3- or 3,4-dicarboxyphenyl) propane, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) propane or anhydrides thereof, and the like Among them, pyromellitic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid or their anhydrides are preferable. These may be used alone or in combination.

As the aliphatic dicarboxylic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecadioic acid, dodecanedioic acid, etc. have a branched structure. Include those having a hydrocarbon substituent on the dicarboxylic acid, such as 2-methylsuccinic acid.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and the like. These may be used alone or in combination.

In addition, aliphatic or alicyclic polycarboxylic acids or their anhydrides or alicyclic dicarboxylic acids can be used as other acid components within the range not impairing the effects of the present invention. For example, butane-1,2,3,4-tetracarboxylic acid, pentane-1,2,4,5-tetracarboxylic acid, cyclobutanetetracarboxylic acid, hexahydropyromellitic acid, cyclohex-1-ene-2,3 , 5,6-tetracarboxylic acid, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic acid, 1-ethylcyclohexane-1- (1,2), 3, 4-tetracarboxylic acid, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic acid, 1,3-dipropyl-1- (2,3), 3- (2,3) -tetra Carboxylic acid, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic acid, bicyclo (2.2.1) heptane-2,3,5,6-tetracarboxylic acid, 1,3-dipropylchlorohexane 1- (2,3), 3 (2,3) - tetracarboxylic acid, hexa hydro trimellitic acid or their anhydrides, cyclohexane dicarboxylic acids, such as dimer acid. These may be used alone or in combination.

In order not to impair the characteristics of the polyamideimide resin of the present invention, the copolymerization amount of the above-mentioned acid component other than trimellitic anhydride and the polyvalent carboxylic dianhydride represented by the general formula (2) 20 mol% or less is desirable and 10 mol% or less is more desirable.

<Diamine component of polyamideimide resin>
Examples of the diamine component of the polyamideimide resin of the present invention include diisocyanate or diamine. Although a diamine component is illustrated as a diisocyanate, the diamine corresponding to a diisocyanate may be sufficient.

  The diamine component of the polyamideimide resin of the present invention may be a diisocyanate or a diamine, preferably an aromatic diisocyanate or an aromatic diamine. Although illustrated as aromatic diisocyanate below, the aromatic diamine corresponding to aromatic diisocyanate may be sufficient.

  Examples of aromatic diisocyanates that can be used in the present invention include diphenylmethane-2,4′-diisocyanate, 3,2′- or 3,3′- or 4,2′- or 4,3′- or 5, 2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4 , 3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4 -Diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene -2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4 '-(2,2bis (4-phenoxyphenyl) ) Propane) Diisocyanate, 3,3'- or 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'- or 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3 '-Jimee Carboxymethyl biphenyl-4,4'-diisocyanate, 3,3'-diethoxy-4,4'-diisocyanate. Among these, diphenylmethane-4,4′-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 3,3′- in terms of low hygroscopicity, dimensional stability, cost and polymerizability. Dimethylbiphenyl-4,4′-diisocyanate and naphthalene-2,6-diisocyanate are preferable, and these may be used alone or in combination.

  As long as the effects of the present invention are not impaired, an aliphatic or alicyclic structure can be used as the diisocyanate component. For example, diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, etc., obtained by hydrogenating any of the components listed in the previous section.

  The logarithmic viscosity of the polyamideimide resin used in the present invention is preferably 0.3 dl / g or more, more preferably 0.5 dl / g or more. Although the upper limit of the logarithmic viscosity of the polyamideimide resin is not particularly defined, it is preferably 3.0 dl / g or less in practice, and more preferably 2.5 dl / g or less from the viewpoint of workability. When the logarithmic viscosity is lower than 0.3 dl / g, the lubricating coating may be peeled off during long-term use.

<Production method of polyamideimide resin>
Generally, the polyamideimide resin can be produced by an acid chloride method, a direct method, or a diisocyanate method, but the diisocyanate method is cheaper and industrially superior.

  Ordinary polyamide-imide resin is synthesized from an acid component and a diisocyanate or diamine component, and amide bonds and imide bonds are alternately repeated in the molecule to form a polymer. Is characterized by high strength and high strength. In order to improve the properties of the polyamide-imide resin, the ratio of amide bond to imide bond can be changed, aromaticity can be increased, or an aliphatic component can be introduced.

Below, although the diisocyanate method is demonstrated to an example about the manufacturing method of the polyamide-imide resin of this invention, this invention is not limited by this.
The polyamide-imide resin of the present invention is obtained by dissolving an acid component and an isocyanate component in a solvent, and heating and stirring at 60 ° C. to 200 ° C., preferably 80 ° C. to 150 ° C. At this time, the ratio (molar ratio) between the acid component and the isocyanate component is preferably in the range of 100: 91 to 100: 109. If it is out of this range, the molecular weight may not be sufficiently increased and the mechanical strength may be insufficient, or gelation may occur during polymerization.

  Examples of the solvent used for the polymerization of the polyamideimide resin of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylimidazolidinone, dimethyl sulfoxide, dimethylformamide, N-ethyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, cyclohexanone, cyclopentanone, tetrahydrofuran and the like can be mentioned. From the viewpoint of storage stability of the polymerization solution, handling workability and polymerizability, N-methyl-2-pyrrolidone or γ- Butyrolactone is preferred. Moreover, it can dilute with the solvent used for superposition | polymerization during superposition | polymerization and / or after superposition | polymerization, and / or another low boiling point solvent, and can adjust a non volatile matter concentration and solution viscosity.

  Low boiling solvents include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, heptane and octane, alcoholic solvents such as methanol, ethanol, propyl alcohol and butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, Examples thereof include ketone solvents such as cyclopentanone and cyclohexanone, ether solvents such as diethyl ether and tetrahydrofuran, and ester solvents such as methyl acetate, ethyl acetate and butyl acetate.

  A catalyst can be used to accelerate the reaction. For example, alkali metals such as potassium fluoride, sodium fluoride, sodium methoxide, triethylamine, triethylenediamine, diethanolamine, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-diazabicyclo (4 , 3,0) -5-Nonene and the like can be used.

<Polyamideimide resin composition for sliding member>
The polyamideimide resin composition for a sliding member of the present invention can be obtained by blending the thus obtained polyamideimide resin with a solid lubricant.

  The solid lubricant used in the present invention is not particularly limited, but metal sulfides such as molybdenum disulfide and tungsten disulfide, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene- Examples include hexafluoropropylene copolymers, tetrafluoroethylene-ethylene copolymers, polyvinylidene fluoride, fluorine compounds such as trichlorotrifluoroethylene, and graphite. Preferred are fluorine compounds such as molybdenum disulfide and trichlorotrifluoroethylene, and graphite. These can be used alone or in combination with a plurality of solid lubricants.

  The blending amount of the solid lubricant (when using a plurality of solid lubricants, the total amount) is preferably 5 to 500 parts by mass, more preferably 10 to 200 parts by mass with respect to 100 parts by mass of the polyamideimide resin. More preferably, it is 25-150 mass parts, Most preferably, it is 50-100 mass parts. When the blending amount of the solid lubricant is less than 5 parts by mass, the effect of reducing the friction coefficient and the seizure resistance may not be sufficiently exhibited. On the other hand, when the blending amount exceeds 500 parts by mass, the polyamideimide component is decreased, and thus the wear resistance may be lowered.

  In the present invention, an antiwear agent can be further blended. The antiwear agent is not particularly limited, but is preferably one or more selected from the group consisting of silicon nitride, alumina, silicon carbide, boron nitride, diamond, and silica. The compounding amount of the antiwear agent is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, and more preferably 20 to 60 parts by mass with respect to 100 parts by mass of the polyamideimide resin. Further preferred. When the blending amount is less than 5 parts by mass, the effect of the antiwear agent is not sufficiently exhibited. When the blending amount exceeds 200 parts by mass, the damage to the sliding partner is increased, and the friction coefficient may be increased. The particle size of the antiwear agent is not particularly limited, but is preferably 0.1 μm to 10 μm, more preferably 0.3 μm to 9 μm, and even more preferably 0.5 to 8 μm. When the particle diameter is less than 0.1 μm, improvement in wear resistance may not be observed. When the particle diameter exceeds 10 μm, the particles may fall off the lubricating coating.

  In order to further improve the wear resistance of the polyamideimide resin composition for sliding members of the present invention, a curing agent can be blended in the polyamideimide resin to crosslink and cure the polyamideimide resin. Although it does not specifically limit as this hardening | curing agent, A polyfunctional epoxy compound, an isocyanate compound, a melamine compound etc. are mentioned, Among these, a polyfunctional epoxy compound is especially preferable from sclerosis | hardenability and the sliding characteristic of the obtained film. Specifically, a bisphenol A type, bisphenol F type, or phenol novolac type polyfunctional epoxy compound is preferred from the viewpoint of curability and the friction characteristics of the resulting coating. Although the compounding quantity of these hardening | curing agents is based also on the kind of hardening | curing agent, it is 1-30 mass parts with respect to 100 mass parts of polyamide-imide resins, Preferably it is 3-20 mass parts. If the blending amount of the curing agent is less than 1 part by mass, the curing of the polyamideimide resin is insufficient and the effect of improving the abrasion resistance is small, and if it exceeds 30 parts by mass, the coating film becomes brittle and the abrasion resistance may be reduced. is there.

  In the polyamideimide resin composition for sliding members of the present invention, a dispersant, a leveling agent, an antifoaming agent, a colorant, a coupling agent, and the like can be blended within a range that does not impair the characteristics of the present invention.

<Production of polyamideimide resin composition for sliding member>
Next, the manufacturing method of the polyamideimide resin composition for sliding members of this invention is demonstrated.
It can be produced by dispersing a solution obtained by adding a solid lubricant or an anti-wear agent to the above-mentioned polyamideimide resin solution using a known facility such as a ball mill, a sand mill, a roll mill, a dissolver, or a planetarium mixer. The timing of blending the curing agent is not particularly limited, but is preferably blended after the dispersion of the main material is completed. Moreover, in order to adjust the solution viscosity of the composition for sliding members, a solvent can be added suitably. As the solvent, the solvent used for the polymerization or dilution of the polyamideimide resin can be used, and the addition time may be any of before the dispersion, during the dispersion, or after the dispersion is completed.

<Formation of lubricating coating>
Moreover, the method to form a lubricating film using the polyamide-imide resin composition for sliding members of this invention is demonstrated.
Examples of the method for applying the polyamideimide resin composition solution for a sliding member of the present invention to the sliding member include a spray method, a dipping method, a roll coating method, a screen printing method, and the like. It can be selected depending on the thickness. The applied sliding member is heat treated for drying and, if necessary, curing. Although this heat processing changes with thickness of a film, it is preferable to carry out in the range for 10 to 100 minutes at 150-220 degreeC. Within 10 minutes at 150 ° C, the solvent may remain, or sufficient sliding characteristics may not be exhibited due to insufficient curing. If it is performed at 220 ° C for 100 minutes or more, the curing agent or solid lubricant may be deteriorated. . The sliding member of the present invention is used for a sliding member for a compressor of an air conditioner, an engine piston of an automobile, a solenoid valve for gas or liquid, a plunger, a valve, a bush, a slide bearing and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
The sliding members tested in the examples and comparative examples were prepared by the following method.

The evaluation shown in the examples was measured by the following method.
1. Solubility Polyamideimide resin solution was filled in a glass container, hermetically sealed, and the dissolution state when left in an atmosphere of 25 ° C. for 24 hours was judged visually.
○: Maintaining transparency ×: Opaque to solidified

2. Logarithmic viscosity 0.5 g of dried polyamideimide resin was dissolved in 100 ml of N-methyl-2-pyrrolidone and immersed in a constant temperature bath at 30 ° C. for 30 minutes or more using an Ubbelohde type viscosity tube. Calculated according to
ηinh (dl / g) = ln (t / t0)
t: passage time of polyamideimide solution, t0: passage time of N-methyl-2-pyrrolidone

3. About 1 g of a solid of polyamideimide resin having a water absorption rate was precisely weighed (w0), immersed in water at 25 ° C. for 24 hours, then weighed again (w1) and obtained by the following formula.
Water absorption rate (%) = [(w1-w0) / w1] × 100

4). Measurement of friction coefficient On a flat plate made of a hardened steel sheet coated with a composition for sliding member to a thickness of about 20 μm, a lower end surface of a cylindrical material (outer diameter 25 mm, inner diameter 20 mm) made of hardened steel having a roughness of about 1 μm RZ is formed. The measurement was performed while rotating the plate at a load of 98 N and 1000 rpm under the pressure and oil bath conditions.

5. Measurement of wear amount Using a Falex ring-on-ring tester, a 35 mm diameter cylinder made of hardened steel with a roughness of about 1 μm RZ was pressed to a block coated with the composition for sliding members with a load of 98 N, and an oil bath. The amount of wear was determined from the result of measuring the surface roughness of the coating after sliding at room temperature for 30 rpm for 10 minutes.

6). Evaluation of water resistance A flat plate of hardened steel coated with a composition for a sliding member to a thickness of about 20 μm was immersed in boiling water for 2 hours and air-dried, and then the adhesion was evaluated by peeling the grid using a cello tape (registered trademark). .
○: 90% or more of the coating film remains Δ: 50 or more and less than 90% of the coating film remains ×: The coating film remains less than 50%

(Synthesis Example 1)
Trimellitic anhydride (TMA) 0.8 mol, 4,4 '-(4,4'-isopropylidenediphenoxy) bisphthalic dianhydride (BISDA) in a four-necked flask with a condenser and a nitrogen inlet ) 0.2 mol, diphenylmethane-4,4′-diisocyanate (MDI) 0.99 mol, diazabicycloundecene (DBU) 0.005 mol with a solid content of 20% N-methyl-2 -Charged with pyrrolidone (NMP). The solution was stirred for 3 hours while raising the temperature to 90 ° C., and further stirred for 3 hours while raising the temperature to 120 ° C. to obtain a polyamideimide resin solution. Table 1 shows the properties of the polyamideimide resin.

(Synthesis Example 2)
In a container similar to Synthesis Example 1, 0.6 mol of TMA, 0.4 mol of BISDA, 0.99 mol of MDI, and 0.01 mol of potassium fluoride (KF) are charged together with NMP so that the solid content concentration becomes 20%, The mixture was stirred for 2 hours while being heated to 120 ° C., stirred for 1 hour while being heated to 120 ° C., and further stirred for 3 hours while being heated to 180 ° C. to obtain a polyamideimide resin solution. Table 1 shows the properties of the polyamideimide resin.

(Synthesis Example 3)
Of the synthesis examples of the polyamideimide resin of Synthesis Example 2, NMP was changed to γ-butyrolactone (GBL), and the temperature was raised to 90 ° C. for 2 hours, raised to 120 ° C. for 1 hour, and further raised to 150 ° C. While stirring for 2 hours, polymerization was carried out to obtain a polyamideimide resin solution. Table 1 shows the properties of the polyamideimide resin.

(Synthesis Example 4)
In the same container as in Synthesis Example 1, 0.2 mol of TMA, 0.8 mol of BISDA, 1 mol of MDI and 0.01 mol of KF were charged together with NMP so that the solid content concentration would be 20%. Stirring was continued for 1 hour while raising the temperature to 120 ° C., and further for 3 hours while raising the temperature to 180 ° C. to obtain a polyamideimide resin solution. Table 1 shows the properties of the polyamideimide resin.

(Comparative Synthesis Example 1)
In a container similar to Synthesis Example 1, 0.05 mol of TMA, 0.95 mol of BISDA, 1.01 mol of MDI, and 0.01 mol of KF were charged together with GBL so that the solid content concentration was 20%, and the temperature was raised to 90 ° C. The polymerization was continued for 2 hours while stirring at 120 ° C. for 1 hour and while stirring at 180 ° C. for 3 hours. This polyamideimide resin solution began to become turbid during the polymerization, and the solubility of the obtained polyamideimide resin was poor. Therefore, the polyamideimide resin composition for sliding members and the sliding members were not prepared, and the characteristics could not be evaluated.

(Comparative Synthesis Example 2)
In the same container as in Synthesis Example 1, 1.0 mol of TMA, 0.99 mol of MDI, and 0.005 mol of KF were charged so that the solid concentration would be 20%, and the temperature was raised to 90 ° C. for 2 hours while increasing the temperature to 90 ° C. While stirring, polymerization was continued for 3 hours to obtain a polyamideimide resin solution. Table 1 shows the properties of the polyamideimide resin.

(Comparative Synthesis Example 3)
In a container similar to Synthesis Example 1, TMA 1 mol, MDI 1 mol, BYK-370 (BYK-Chemie OH group-containing polyester-modified polysiloxane solid content concentration 25%) 71 g and NMP 830 g were charged in about 30 minutes with stirring. The temperature was raised to 120 ° C. and polymerization was carried out for 5 hours. The properties of the obtained resin are shown in Table 1.

(Example 1)
To 100 g of the polyamideimide resin solution obtained in Synthesis Example 1, 5 g of polytetrafluoroethylene (PTFE), 10 g of graphite and 5 g of silicon nitride are added and dispersed for 30 minutes with a dissolver, and then passed through a three-roll mill twice. A polyamideimide resin composition for a moving member was obtained. Degrease the sliding surface of the test piece for measuring friction and wear characteristics to remove dirt and oil on the surface, and then apply the polyamideimide resin composition for the sliding member so that the film thickness after drying is about 20 μm. Then, heat treatment was performed at 200 ° C. for 100 minutes in a hot air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

(Example 2)
To 100 g of the polyamideimide resin solution obtained in Synthesis Example 2, 5 g of PTFE, 10 g of graphite, and 5 g of silicon nitride are added and dispersed for 30 minutes with a dissolver. I got a thing. After degreasing the sliding surface of the test piece for measuring the friction and wear characteristics to remove dirt and oil on the surface, the film thickness after drying the polyamideimide resin composition solution for the sliding member is about 20 μm. It apply | coated and heat-processed for 100 minutes at 200 degreeC in hot-air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

(Example 3)
To 100 g of the polyamideimide resin solution obtained in Synthesis Example 3, 5 g of PTFE, 10 g of graphite, and 5 g of silicon nitride are added and dispersed for 30 minutes with a dissolver. I got a thing. After degreasing the sliding surface of the test piece for measuring the friction and wear characteristics to remove dirt and oil on the surface, the film thickness after drying the polyamideimide resin composition solution for the sliding member is about 20 μm. It apply | coated and heat-processed for 100 minutes at 200 degreeC in hot-air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

Example 4
To 100 g of the polyamideimide resin solution obtained in Synthesis Example 4, 5 g of PTFE, 10 g of graphite, and 5 g of silicon nitride are added and dispersed for 30 minutes with a dissolver. I got a thing. After degreasing the sliding surface of the test piece for measuring the friction and wear characteristics to remove dirt and oil on the surface, the film thickness after drying the polyamideimide resin composition solution for the sliding member is about 20 μm. It apply | coated and heat-processed for 100 minutes at 200 degreeC in hot-air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

(Comparative Example 1)
The polyamideimide resin solution synthesized in Comparative Synthesis Example 1 could not be made into a paint due to poor dissolution.

(Comparative Example 2)
To 100 g of the polyamideimide resin solution obtained in Comparative Synthesis Example 2, 5 g of PTFE, 10 g of graphite, and 5 g of silicon nitride are added, dispersed for 30 minutes with a dissolver, and then passed twice through a three roll mill for polyamideimide resin for sliding members. A composition was obtained. After degreasing the sliding surface of the test piece for measuring the friction and wear characteristics to remove dirt and oil on the surface, the film thickness after drying the polyamideimide resin composition solution for the sliding member is about 20 μm. It apply | coated and heat-processed for 100 minutes at 200 degreeC in hot-air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

(Comparative Example 3)
To 100 g of the polyamideimide resin solution obtained in Comparative Synthesis Example 3, 5 g of PTFE, 10 g of graphite, and 5 g of silicon nitride are added, dispersed for 30 minutes with a dissolver, and then passed twice through a three roll mill for polyamideimide resin for sliding members. A composition was obtained. After degreasing the sliding surface of the test piece for measuring the friction and wear characteristics to remove dirt and oil on the surface, the film thickness after drying the polyamideimide resin composition solution for the sliding member is about 20 μm. It apply | coated and heat-processed for 100 minutes at 200 degreeC in hot-air oven. Table 2 shows the results of evaluating the water resistance, coefficient of friction, and amount of wear of the obtained test pieces.

The polyamideimide resin composition for a sliding member of the present invention has a low friction and wear resistance that is stable even in a high humidity atmosphere for a long time because the polyamideimide resin itself is excellent in solubility in organic solvents and has low water absorption. It is useful for sliding members such as automobile engine pistons and air conditioner compressors.

Claims (9)

A polyamideimide resin composition for a sliding member, comprising a polyamideimide resin containing 10 to 90 mol% of a structural unit represented by the following general formula (1) in a polyamideimide resin, and a solid lubricant.
(In the general formula (1), R ₁ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ —. R ₂ and R ₃ may be the same or different, and may be hydrogen, halogen atom, aryl group or Represents an alkyl group having 1 to 3 carbon atoms, provided that when R ₁ is —SO ₂ —, R ₄ represents an aryl group which may have a substituent. The polyamide-imide resin includes a structural unit derived from trimellitic anhydride, a structural unit derived from a polycarboxylic dianhydride represented by the following general formula (2), and a structural unit derived from diisocyanate or diamine, And when the sum total of the structural unit derived from the acid component in a polyamide-imide resin is 100 mol%, the structural unit derived from the polyhydric carboxylic dianhydride shown by General formula (2) is 10-90 mol%. The polyamideimide resin composition for sliding members according to claim 1.
(In the general formula (2), R ₅ represents an alkyl group having 1 to 5 carbon atoms or —SO ₂ —. R ₆ and R ₇ may be the same or different, and may be a hydrogen atom, a halogen atom, an aryl group or Represents an alkyl group having 1 to 3 carbon atoms, provided that R ₅ is —SO ₂ —.   The polyvalent carboxylic dianhydride represented by the general formula (2) is 4,4 ′-(4,4′-isopropylidenediphenoxy) bisphthalic dianhydride, 4,4 ′-(4,4 ′. -Hexafluoropropylidenediphenoxy) bisphthalic dianhydride, 4,4 '-(4,4'-diphenylpropylidenediphenoxy) bisphthalic dianhydride, 4,4'-(4,4'-ethylenedi The slide according to claim 2, which is at least one compound selected from the group consisting of phenoxy) bisphthalic dianhydride and 4,4 '-(4,4'-sulfonyldiphenoxy) bisphthalic dianhydride. Polyamideimide resin composition for moving members.   The polyamideimide resin composition for a sliding member according to any one of claims 1 to 3, wherein the solid lubricant is at least one selected from the group consisting of metal sulfides, fluorine compounds and graphite.   The fluorine compound is polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, and trichlorotrifluoro The polyamideimide resin composition for sliding members according to claim 4, wherein the composition is one or more selected from the group consisting of ethylene.   The polyamideimide resin composition for a sliding member according to any one of claims 2 to 5, wherein the structural unit derived from diisocyanate or diamine is a structural unit derived from aromatic diisocyanate or aromatic diamine.   Furthermore, the polyamideimide resin composition for sliding members according to any one of claims 1 to 6, further comprising an antiwear agent.   The lubricating film containing the polyamide-imide resin composition in any one of Claims 1-7.   The sliding member using the polyamide-imide resin composition in any one of Claims 1-7.