JPH0567662B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition suitable for a sliding member having excellent self-lubricity and wear resistance and having an aromatic polyester resin having excellent heat resistance and moldability as a base material. Aromatic polyesters produced from terephthalic acid, isophthalic acid, or derivatives thereof, and 2,2-bis(4'-hydroxyphenyl)propane or derivatives thereof are known as resins with excellent various properties. As a method for producing such aromatic polyesters, there is an interfacial polymerization method (Japanese Patent Publication No. 40, 1973) in which aromatic dicarboxylic acid dichloride dissolved in an organic solvent incompatible with water and bisphenols dissolved in an alkaline aqueous solution are mixed and reacted. −
Publication No. 1959, Japanese Unexamined Patent Publication No. 1974-74299, Japanese Unexamined Patent Publication No. 1973
-101500, JP 57-180631), a solution polymerization method in which aromatic dicarboxylic acid dichloride and bisphenols are reacted together in an organic solvent (Japanese Patent Publication No. 37-5599), Melt polymerization method in which phenyl ester and bisphenols are reacted by heating (Japanese Patent Publication No. 38-15247,
Japanese Patent Publication No. 38-26299, Japanese Patent Publication No. 43-28119) are known. Aromatic polyester produced by this method has mechanical properties such as tensile strength and bending strength, thermal properties such as heat distortion temperature and pyrolysis temperature, specific resistance value, dielectric breakdown, arc resistance, and dielectric constant. It has excellent performance in terms of electrical properties such as dielectric loss. For this reason, these aromatic polyester resins are widely used in the fields of mechanical parts, aircraft parts, automobile parts, and electrical/electronic parts as molded products by extrusion molding, injection molding, compression molding, rotary molding, etc. . Various sliding members that take advantage of their heat resistance are being considered as uses for these aromatic polyester resins. However, these aromatic polyesters alone are insufficient for use in sliding members in terms of self-lubricating properties and wear resistance. In general, as a measure to improve the sliding properties such as self-lubricity and wear resistance of resins for sliding parts, solid lubricants such as graphite and molybdenum disulfide are added (for example,
56-61458), blends of resins having a low coefficient of friction such as tetrafluoroethylene resin (e.g., Japanese Patent Publication No. 56-135163, Japanese Patent Application Laid-Open No. 1987-135163),
Blends of lubricants such as mineral oil, wax, and metal soap (e.g., Japanese Patent Publication No. 5321/1983,
Although methods such as JP-42615) are known, it cannot be said that any of these methods sufficiently improves the sliding characteristics. Products containing the above-mentioned solid lubricants have improved load resistance, but hardly any improvement in self-lubricating properties. Furthermore, products containing resins with low coefficients of friction such as tetrafluoroethylene have a considerable effect on improving self-lubricity, but wear resistance is insufficient, and the mechanical strength and load capacity of molded products are A decline in sexuality is inevitable. Furthermore, when a material containing a lubricant or the like dispersed therein is used by adhering or adhering to another object, it is inconvenient that it is oil-impregnated. As a result of intensive studies on improving the sliding properties of aromatic polyester, the present inventors found that by blending fluororesin and aromatic polyamide fibers with aromatic polyester, sliding properties such as self-lubricity and abrasion resistance can be improved. The present invention was completed based on the discovery that significant improvements can be made in both cases. That is, the present invention provides (a) general formula (1)

[Chemical formula] (In the formula, R ¹ to ^{R 8} represent a hydrogen atom, a halogen atom, or a hydrocarbon group consisting of 1 to 10 carbon atoms,
X is a divalent hydrocarbon having 1 to 20 carbon atoms, -O-, -S
-, _-SO2- , -CO-, and two or more types may be contained at the same time. a represents 0 or 1, and when it is 0, it means that the aromatic rings are directly bonded. The carbonyls substituted on the aromatic ring are in the m- and/or p-positions of each other. n indicates the degree of polymerization. ) containing 3 to 60 parts by weight of fluororesin and 3) 3 to 60 parts by weight of aromatic polyamide fiber per 100 parts by weight of an aromatic polyester resin represented by the following formula and having a logarithmic viscosity in the range of 0.2 to 2.0. The present invention provides a lubricating resin composition characterized by the following. Bisphenols that can be used in the production of the aromatic polyester resin represented by the general formula (1) used in the present invention include 2,2-bis(4'-hydroxyphenyl)propane, bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)propane. enyl)methane, 2,2-bis(4'-hydroxy3'-methylphenyl)propane, 2,2-
Bis(3'-chloro4'-hydroxyphenyl)propane, 1,1-bis(4'-hydroxyphenyl)
Cyclohexane, 1,1-bis(4'-hydroxyphenyl)isobutane, 1,1-bis(4'-hydroxyphenyl)diphenylmethane, 2,2-bis(3',5'-dimethyl 4'-hydroxyphenyl) enil)
Propane, bis(3,5-dimethyl4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(3-hydroxyphenyl)sulfoxide, ,5-dimethyl4-
hydroxyphenyl) sulfide, bis(3,5
-dimethyl 4-hydroxyphenyl) sulfone,
4,4'-dihydroxybiphenyl, 3,3',5,
5'-tetramethyl 4,4'-dihydroxybiphenyl, 2,2-bis(3',5'-dibromo4'-hydroxyphenyl)propane, bis(1-hydroxyphenyl)ketone, 2,2- Bis(3′,5′-diphenyl4′-hydroxyphenyl)propane, 1,
1-bis(4'-hydroxyphenyl)1-phenylethane, bis(3-hydroxyphenyl) sulfide, bis(3-hydroxyphenyl)sulfone, 3,3'-dihydroxybiphenyl, bis(3-hydroxyphenyl)
-hydroxyphenyl) ether, 3-hydroxyphenyl 4-hydroxyphenyl ether, etc., and these can be used alone or as a mixture of two or more types. The aromatic polyester used in the present invention has a logarithmic viscosity ηinh determined by the measurement method described below.
is in the range of 0.2 to 2.0, preferably 0.3 to 0.8. The fluororesin used in the present invention is a synthetic polymer containing fluorine atoms (F) in its molecules,
Generally, compared to other synthetic resins, it has excellent heat resistance, chemical resistance, electrical properties, especially high frequency properties, and has unique low friction properties and non-stick properties. For example, compounds having the following structural formulas may be mentioned, and at least one kind or a mixture of two or more kinds thereof may be used. (1) [−CF ₂ CF ₂ ]− _o : Polytetrafluoroethylene (PTFE) (2) [−CF ₂ CF ₂ (CF ₃ )CF ₂ ]− _o : Tetrafluoroethylene-hexafluoropropylene copolymerization Resin (FEP) (3) [−(CF ₂ CF ₂ ) _o (CF[OR]CF ₂ )] − _p : Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) (4) [−CF ₂ CF ₂ CF(CF ₃ )CF ₂ −CF(OR)CF ₂ 〕−
_o : Tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer resin (EPE) (R is a fluoroalkyl group
CnF _2o+1 ) (5) [−CH ₂ CH ₂ CF ₂ CF ₂ ]− _o : Tetrafluoroethylene−
Ethylene copolymer resin (ETFE) (6) [−CH ₂ CH ₂ CFC1CF ₂ ] − _o : Trifluorochloroethylene resin (ECTFE) (7) [−CF ₂ CH ₂ ] − _o : Vinylidene fluoride resin (PVDF ) (8) [−CFC1CF ₂ ]− _o : Polychlorotrifluoroethylene (PCTFE) (9) [−CH ₂ CHF]− _o : Polyvinyl fluoride (PVF) Among the above-mentioned fluororesins, it is completely fluorinated. Polytetrafluoroethylene resin (PTFE) has particularly excellent properties and is most preferably used in the present invention. The amount of these fluororesins added in the present invention is in the range of 3 to 60 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the above-mentioned aromatic polyester. If the amount of the fluororesin added is less than 3 parts by weight, the effect of improving the self-lubricity of the resulting resin composition will be undesirable. Further, if the amount of the fluororesin added is more than 60 parts by weight, the mechanical properties and moldability of the resulting resin composition will deteriorate, which is not preferable. Furthermore, the aromatic polyamide fiber used in the present invention is a relatively newly developed heat-resistant organic fiber that is expected to be used in various fields by making use of many unique properties. At least one kind or a mixture of two or more of these can be used. (1)

[ka] Example) DuPont, product name “Kevlar” (2)

[C] Example: DuPont, product name “Nomex” Teijin, product name “Conex” (3)

[Chemical] In addition, aromatic polyamide fibers with various skeletons can be considered by creating appropriate isomeric structures such as ortho, meta, and para, but among them, the one with para-para bond (1) has a high softening point and melting point. In the present invention, it is most preferably used as a heat-resistant organic fiber.
The amount of aromatic polyamide fiber added in the present invention is in the range of 3 to 60 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the above-mentioned aromatic polyester. If the amount of aromatic polyamide fiber added is less than 3 parts by weight, the effect of improving the abrasion resistance of the resulting resin composition is undesirable. Further, if the amount of aromatic polyamide fiber added is more than 60 parts by weight, the mechanical properties and moldability of the resulting resin composition will deteriorate, which is not preferable. Further, from the viewpoint of mechanical properties and moldability of the resulting resin composition, it is more preferable that the total amount of the fluororesin and aromatic polyamide fiber added is 100 parts by weight or less based on 100 parts by weight of the aromatic polyester. The resin composition of the present invention may further contain fibrous reinforcing materials such as carbon fibers and glass fibers, granular reinforcing materials such as calcium carbonate, talc, silica, etc., antioxidants and heat stabilizers, as long as the object of the present invention is not impaired. Usual additives such as lubricants such as phenolic antioxidants and phenolphosphite antioxidants, stearic acid and its metal salts as mold release agents, and pigments can be added as agents. There are no particular restrictions on the method of adding the fluororesin and aromatic polyamide fiber to the aromatic polyester of the present invention, and various means can be adopted. After that, it is generally fed into an extruder, melted and kneaded, and extruded into pellets. The lubricating resin composition of the present invention thus obtained can be molded into any molded product by a molding method such as injection molding, extrusion molding, or compression molding, and the molded product has excellent sliding properties. Taking advantage of its dynamic properties, it is used in various sliding parts such as various bearings, piston rings, gears, cams, and various valve parts. The present invention will be explained in more detail below with reference to Examples. Note that the logarithmic viscosity ηinh in the following examples is phenol/tetrachloroethane (weight ratio 6/4)
Using a mixed solvent of 0.5g/dl solution, it is determined by the following formula. ηinh.=1/Cloget ₁ /t ₂ (In the above formula, t ₁ is the flow time of the polymer solution, t ₂ is the flow time of only the solvent, and C is the polymer solution concentration (g/dl).) Examples 1-9 and Comparative Examples 1-4 Bis(4-hydroxyphenyl)sulfone 3.5
Kg, 2,2-bis(4'-hydroxyphenyl)propane 1.37Kg, and O-phenylphenol
238g was placed in a reactor, 88% of a 2% aqueous sodium hydroxide solution was added to dissolve it, and the mixture was cooled to 10°C. _N2
A stream of air was passed through the solution for 30 minutes and 10 g of cetyltrimethylammonium bromide was added. Add 4.20 kg of a mixture of isophthaloyl chloride and terephthaloyl chloride (1:1) to 60 kg of dichloromethane.
was added all at once to the solution in the above-mentioned reactor, which was maintained at 10°C and stirred, and stirring was continued for 1 hour while maintaining the temperature at 10°C. As a result of sampling the reaction solution and analyzing it by gel permeation chromatography for low molecules, no unreacted monomer was observed.
Next, 3 portions of a 1N hydrochloric acid aqueous solution was added, followed by 30 g of water, stirred, and allowed to stand to separate the lower layer, which was further washed twice with 30 g of water. Stir the dichloromethane layer after washing at high speed with a homomixer120
of methanol to precipitate the polymer.
The precipitated colorless polymer was separated, further washed with methanol, and dried to obtain 7.43 kg of polymer powder. (hereinafter abbreviated as Polymer A) The logarithmic viscosity of the obtained Polymer A was 0.54.
From the NMR spectrum, bis(4
-hydroxyphenyl)sulfone residue and 2,2-
The abundance ratio of bis(4'-hydroxyphenyl)propane residues was approximately 7:3. Polymer A thus obtained, fluororesin powder (manufactured by Mitsui Fluorochemical Co., Ltd., tetrafluoroethylene resin, trade name Teflon TLP-10) and aromatic polyamide fiber (manufactured by DuPont Company, trade name
After mixing the amount of Kevlar shown in Table 1, the cylinder temperature was 340°C using a single-screw extruder with a diameter of 40 mm.
It was extruded into pellets. Further, test pieces were molded from the pellets using an injection molding machine at a cylinder temperature of 350 to 380°C and a mold temperature of 150°C, and the sliding properties were measured, and the results shown in Table 1 were obtained. The coefficient of friction was measured at room temperature using a Matsubara friction tester under the conditions of a surface pressure of 10 kg/cm ² and a speed of 10 cm/sec, using stainless steel as the mating material. The wear coefficient was measured at room temperature using a cylindrical wear tester under the conditions of a surface pressure of 5 kg/cm ² and a speed of 100 m/min.

[Table] Examples 10 to 12 and Comparative Examples 5 to 9 In Example 1, 4.6 kg of 2,2-bis(4'-hydroxyphenyl)propane and bis(4-hydroxyphenyl)sulfone were used. The reaction and post-treatment operations were carried out in the same manner as in Example 1, except that 7.0 kg of colorless polymer powder was obtained. (Hereinafter abbreviated as Polymer B) The logarithmic viscosity of Polymer B thus obtained was 0.76. This polymer B, fluorine resin powder (tetrafluoroethylene resin trade name Teflon TLP-10 manufactured by Mitsui Fluorochemical Co., Ltd.), aromatic polyamide fiber (trade name Kevlar manufactured by DuPont Company), and glass fiber (manufactured by Nippon Sheet Glass Co., Ltd.) After mixing the amounts shown in Table 2, tests were conducted in the same manner as in Example 1, and the results are shown in Table 2.

【table】

Claims (1)

[Scope ^of Claims] 1 A General formula ( ¹ )
X is a divalent hydrocarbon having 1 to 20 carbon atoms, -O-, -S
-, _-SO2- , -CO-, and two or more types may be contained at the same time. a represents O or 1, and when it is O, the aromatic ring is directly bonded. The carbonyl substituted on the aromatic ring is m- and/or p-
It is in the position. n indicates the degree of polymerization. ) and has a logarithmic viscosity in the range of 0.2 to 2.0, per 100 parts by weight of aromatic polyester resin,
and c) 3 to 60 parts by weight of aromatic polyamide fiber.