JPH11140312A - Thrustwasher comprising im-mold crystallizing polyimide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded article showing excellent surface smoothness and good slidability by forming a crystalline polyimide resin having logarithmic viscosity in a specific range. SOLUTION: A fiber-reinforced resin composition comprises 100 pts.wt. of a crystalline polyimide resin having a repeating unit represented by formula I and a logarithmic viscosity of 0.1-3.0 dl/g and 5-100 pts.wt. of a fibrous reinforcement such as a carbon fiber, a glass fiber, etc. A molded article is obtained by crystallizing said resin composition in a mold heated at 180-280 deg.C during injection molding. The polyimide resin is obtained by making a diamine represented by formula II react on a tetracarboxylic acid dianhydrides represented by formula III in a solvent such as N,N'-diethylacetamide at an ambient temperature to 250 deg.C in an equivalent ratio of the tetracarboxylic acid to the diamine of 0.90-0.99 to produce a polyamide acid as a precursor and then heating the precursor at 100-300 deg.C for imide reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has excellent surface smoothness,
The present invention relates to a thrust washer which has good sliding characteristics, does not require post-annealing, and significantly reduces manufacturing costs.

[0002]

2. Description of the Related Art Thrust washers used for automobile parts, office equipment parts, compressor parts, and other sliding parts have recently been replaced with metal by using resin. Increasingly severe.

As a polymer material which can be used at such a high temperature, there is a polyimide resin. As a conventionally developed thrust washer, JP-A-62-236858,
Japanese Patent Application Laid-Open No. 62-253655 discloses a method using a thermoplastic polyimide resin. However, since the rate of crystallization is low, it is difficult to take out a crystallized state in a mold during injection molding. However, it must be used in an amorphous state, and thus it cannot be said that the heat resistance inherent to the polyimide resin is sufficiently exhibited. In order to sufficiently exhibit heat resistance, there is a means called crystallization. The polyimide resin can be post-crystallized using an oven or the like, but it takes time, or the dimensional change accompanying crystallization occurs during post-crystallization, or the surface roughness is poor due to post-crystallization. However, there are problems such as insufficient performance as a thrust washer material. To solve these problems, a material that crystallizes in a mold at the time of injection molding has been required. Then, the present inventors further disclosed in JP-A-07-1903.
As disclosed in No. 69, it has been found that the crystallization rate can be remarkably improved by adding a specific graphite to a thermoplastic polyimide. As a result, a polyimide resin crystallized in the mold could be obtained.However, the mold temperature was extremely high, and there were various problems such as galling of the mold and deformation of the product at the time of protrusion. It was inadequate and not satisfactory as a material for thrust washers.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a thrust washer which has excellent surface smoothness, good sliding characteristics, does not require post-annealing, and significantly reduces manufacturing costs. It is intended for.

[0005]

The present inventors have studied various types of general-purpose plastics and engineered plastic thrust washers in order to solve these problems. As a result, the thermoplastic crystalline polyimide which crystallizes in the mold is obtained. The inventors have found that a thrust washer crystallized in a mold by injection molding using a resin composition containing a resin is optimal, and have completed the present invention. That is, the present invention is specified by the matters described in the following (1) to (5).

(1) General formula (1)

[0007]

Embedded image A thrust washer comprising a crystalline polyimide resin having a repeating structural unit represented by the formula: and a logarithmic viscosity (ηinh) in the range of 0.1 to 3.0 dl / g.

(2) It has a repeating structural unit of the general formula (1) (formula 2), and has a logarithmic viscosity (ηinh) of 0.1 to 3.
A thrust washer comprising a fiber-reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin in a range of 0 dl / g.

(3) It has a repeating structural unit represented by the general formula (1) (formula 2) and has a logarithmic viscosity (ηinh) of 0.1 to 3.
A method for producing a thrust washer, wherein a crystalline polyimide resin having a range of 0 dl / g is crystallized in a mold at the time of injection molding.

(4) It has a repeating structural unit represented by the general formula (1) (formula 2) and has a logarithmic viscosity (ηinh) of 0.1 to 3.
When injection-molding a fiber-reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin in a range of 0 dl / g, crystallization is performed in a mold. Thrust washer manufacturing method.

(5) A thrust washer obtained by the production method described in (3) or (4).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Crystallization of a resin composition provided to a thrust washer of the present invention is achieved in a mold. By achieving crystallization in the mold, the heat resistance inherent to the polyimide resin is exhibited, and a molded product with less dimensional change due to a method such as post-crystallization can be obtained.

The polyimide resin used in the present invention is a diamine represented by the general formula (2)

[0014]

Embedded image And a tetracarboxylic dianhydride represented by the general formula (3):

[0015]

Embedded image And dehydration co-condensation of

The molecular weight of the polyimide is a logarithmic viscosity (ηin
h) is in the range of 0.1 to 3.0 dl / g. Preferably it is in the range of 0.2 to 2.0 dl / g, more preferably 0.1 to 2.0 dl / g.
Range from 3 to 1.5 dl / g, most preferably from 0.4 to
It is in the range of 1.0 dl / g. If it is less than 0.1 dl / g, the molecular weight is low and the strength as a molded product cannot be sufficiently exhibited. If it exceeds 3.0 dl / g, the molecular weight is too high, and melt molding such as injection molding becomes difficult.

In the present invention, the logarithmic viscosity (ηin)
h) is p-chlorophenol / phenol (weight ratio 9)
/ 1) A value measured at 35 ° C. after heating and dissolving 0.50 g of polyimide powder in 100 ml of a mixed solvent. A known imidization reaction can be applied to the method for producing the polyimide resin.

The amount of the starting compound used is usually from 0.90 equivalent of tetracarboxylic dianhydride to 1 equivalent of diamine.
It is in the range of 0.99 equivalents. Preferably 0.93-0.
985, more preferably 0.95 to 0.98. If the molecular weight is less than 0.90 equivalent, the molecular weight is not sufficiently high, so that the mechanical properties of the obtained polymer may not be sufficient. If it exceeds 0.99, there is a problem that the molecular weight becomes too high and the fluidity is impaired.

In the synthesis of the polyimide, it is desirable to seal the reactive end of the molecule with phthalic anhydride or the like. By sealing the reaction end, the thermal stability is significantly improved. The reaction is particularly preferably performed in an organic solvent. Examples of the solvent usable here include N, N-dimethylformamide, N, N-diethylacetamide, N, N-dimethoxyacetamide, N-methyl-2-pyrrolidone,
3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2 -Methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-
Dioxane, 1,4-dioxane, pyrroline, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea hexamethylphosphoramide, phenol,
o-cresol, m-cresol, p-cresol, p
-Chlorophenol, anisole, benzene, toluene, xylene and the like. These may be used alone or in combination of two or more.

The reaction temperature is usually in the range from room temperature to 250 ° C, preferably in the range from 140 ° C to 200 ° C. The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure. The reaction time varies depending on the type of the solvent and the reaction temperature, but is usually 4 to 24.
Time.

Further, as a method of imidization, the polyamic acid as a precursor is imidized by heating to 100 to 300 ° C. or chemically imidized using an imidizing agent such as acetic anhydride. Is obtained.

When the resin composition is used, the mold temperature is in the range of 180 to 280 ° C. Preferably 190-2
It is in the range of 70C, more preferably in the range of 200-265C, most preferably in the range of 210-260C. 2
If the mold temperature exceeds 80 ° C., the molded product may not be released. At a mold temperature of less than 180 ° C., the crystallization of the crystalline polyimide resin does not sufficiently proceed, and the heat resistance at a high temperature peculiar to the polyimide resin cannot be exhibited as it is. When a molded article is taken out in an amorphous state and then crystallized, deformation may increase with the post-crystallization, and a shape that can withstand use may not be maintained.

As long as the object of the present invention is not impaired, other thermoplastic resins can be added in an appropriate amount according to the purpose. Thermoplastic resins that can be blended include polyether ketone, polyether ether ketone, polyether ketone ketone, polyether ketone ether ketone ketone, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, polyamide,
Polyamide imide, polyphenylene ether, polyacetal, polyether imide, polyether sulfone,
Polysulfone and other thermoplastic polyimides.

It is also possible to mix a thermosetting resin and a filler to such an extent that the object of the invention is not impaired. Examples of the thermosetting resin include a phenol resin and an epoxy resin. Examples of the filler include a silica powder, molybdenum disulfide, an abrasion resistance improving material such as a fluororesin, carbon fiber, glass fiber, aromatic polyamide fiber, alumina fiber, boron fiber, silicon carbide fiber, potassium titanate whisker, and aluminum borate. Reinforcing materials such as whiskers, carbon whiskers, asbestos, metal fibers, and ceramic fibers; flame retardant materials such as antimony trioxide, magnesium carbonate, and calcium carbonate; electric property improving materials such as clay and mica; asbestos and silica; Tracking resistant material,
Acid-resistance improving materials such as barium sulfate, silica, calcium metasilicate, etc .; thermal conductivity improving materials such as iron powder, zinc powder, aluminum powder, and copper powder; and other polybenzimidazole resins, silicon resins, glass beads, talc, and diatoms Soil, alumina, silas balun, hydrated alumina, metal oxides, coloring agents, release agents, various stabilizers, plasticizers and the like.

The resin composition of the present invention can be produced by a generally known method, but the following method is particularly preferable.

(1) Preliminary mixing of crystalline polyimide resin powder, fibrous reinforcing material such as carbon fiber, and other additives using a mortar, a Henshal mixer, a drum blender, a tumbler blender, a ball mill, a ribbon blender, etc. Next, the mixture is kneaded with a generally known melt extruder, melt mixer, hot roll, or the like, and then pelletized or powdered.

(2) The crystalline polyimide resin powder and other additives are dissolved or suspended in an organic solvent in advance, and a fibrous reinforcing material such as carbon fiber is immersed in the solution or suspension. Is removed in a hot air oven and then pelletized or powdered.

In this case, the solvent used is, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N
-Dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone,
N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-
[Methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphoramide and the like. These organic solvents may be used alone or in combination of two or more.

The resin composition of the present invention is molded by a known molding method such as an injection molding method, an extrusion molding method, a compression molding method, a transfer molding method, and put into practical use. The surface properties of the thrust washer of the present invention are remarkably improved as compared with the post-annealed one by crystallization in the mold during injection molding. This improvement in the surface properties leads to a marked improvement in the properties of the thrust washer, that is, the friction and wear properties. Compared with the amorphous thrust washer of the prior art, the surface properties are clearly better in the mold crystallized in the mold.

Further, by crystallization in a mold at the time of injection molding, the dimensional accuracy can be more easily predicted than in the case of post-annealing, and the dimensional accuracy can be accurately controlled in practice. The appearance of the molded article is extremely good. It is clear that the crystallization in the mold does not require post-annealing to complete the crystallization, greatly reducing the processing cost.

[0031]

The present invention will be described in more detail with reference to the following examples. [Synthesis Example of Polyimide Resin] 140 g (0.7 mol) of 3,4′-diaminodiphenyl ether and 3,3 ′, 4 were placed in a container equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube.
45.5-biphenyltetracarboxylic dianhydride 195.5
g (0.665 mol), 10.4 g of phthalic anhydride (0.
1 mol) and 1480 g of m-cresol, and heated to 200 ° C. while stirring under a nitrogen atmosphere. Thereafter, the reaction was carried out at 200 ° C. for 4 hours.
Distillation of 1 l of water was confirmed. After the completion of the reaction, the mixture was cooled to room temperature, charged with about 2000 ml of toluene, and then the polyimide powder was separated by filtration. After washing this polyimide powder with toluene, it was dried at 250 ° C./5 hours in nitrogen to obtain a polyimide powder. Ηinh of the obtained polyimide powder is 0.55 d
1 / g.

Example 1 The polyimide resin and carbon fiber obtained in the synthesis example (HTA-C6-T manufactured by Toho Rayon Co., Ltd.)
X) was blended and mixed at the ratios shown in Table 1, and then melt-kneaded at 410 ° C. with an extruder having a diameter of 40 mm to obtain pellets.
The obtained pellets were molded by an injection molding machine having a mold clamping force of 100 tons under conditions of a cylinder temperature of 410 ° C. and a mold temperature of 230 ° C. to form ASTM bending test pieces, Suzuki-type friction and wear test pieces, and thrust washers. A molded product was obtained.
A good appearance and a glossy thrust washer were obtained. The molding conditions and the like are summarized in Table 1 [Table 1].

(1) Deflection temperature under load Measured according to ASTM-D-648 using a bending test piece. (2) Surface roughness Using a thrust washer molded product, R
a was determined. The thrust washer was attached as shown in FIG. The test conditions were a transmission pressure of 7 kg, a surface pressure of 20 kg / cm ² , and a speed of 250 m / min.
And the surface roughness before and after the test was measured. (3) Friction coefficient, specific wear amount (non-lubricated) A Suzuki-type friction and wear test was performed at a surface pressure of 5 kg / cm ² and a speed of 50 m / min under the conditions of SUS304 as a mating material and 7 hours without lubrication. After 7 hours, the friction coefficient and the specific wear amount were measured. (4) Coefficient of friction, specific wear (in oil) SUS304 as a mating material, transmission pressure in oil for 7 hours, surface pressure 20 kg / cm ² , speed 25
A Suzuki friction and wear test was performed at 0 m / min. After 7 hours, the friction coefficient and the specific wear amount were measured. The experimental results are summarized in Table 2 [Table 2].

Comparative Example 1 An experiment was conducted in the same manner as in Example 1 except that the resin used was changed to thermoplastic polyimide "AURUM PL450" (registered trademark: manufactured by Mitsui Chemicals, Inc.). The experimental results and the like are summarized in Table 1 [Table 1] and Table 2 [Table 2]. Since all the test pieces obtained in this comparative example were obtained in an amorphous state, 260 ° C./10 h and 300 ° C./2
h for post-annealing for crystallization.

[0035]

[Table 1]

[0036]

[Table 2] [Legend] ⁽¹⁾ All figures are for mold removal products. ⁽²⁾ Unit: 10 ^-10 cm ³ / kgfm

[0037]

As described above, the thrust washer using the crystalline polyimide resin composition that crystallizes in the mold according to the present invention has a remarkably improved function as a washer material, and has no lubrication and oil lubrication. Any of the following can be used. At this time, any of a hard metal such as steel and FCD and a soft metal such as Al and Cu can be used as a sliding partner material. Specifically, it can be used for a thrust washer required when using an automobile part, an office equipment part, a compressor part and other sliding members. The heat resistance is improved and the friction and wear characteristics are improved, and the performance is remarkably improved. The significance of the invention is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a thrust washer evaluation device used in Examples and Comparative Examples.

[Explanation of symbols]

a: FCD (cast iron) 45 shaft. (The arrow indicates the direction of rotation.) B; FCD (cast iron) 45 jig. c; thrust washer. (Outer diameter = 60 mm, inner diameter = 3
(0 mm, wall thickness = 2 mm, oil groove = 4 locations per side, total 8 locations) d; SUS304 mating sliding material. e: Transmission oil atmosphere. P: pressure (surface pressure = 20 kg / cm ² ). (The arrow indicates the direction in which pressure is applied.) V; speed (speed = 250 m / min). (Rotating movement,
Arrows indicate the direction of rotation. )

Claims (5)

[Claims] 1. A compound represented by the general formula (1): A thrust washer comprising a crystalline polyimide resin having a repeating structural unit represented by the formula: and a logarithmic viscosity (ηinh) in the range of 0.1 to 3.0 dl / g. 2. It has a repeating structural unit of the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 dl.
A thrust washer comprising a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin in a range of / g. 3. It has a repeating structural unit of the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 dl.
A method for producing a thrust washer, characterized by crystallizing in a mold when injection molding a crystalline polyimide resin in the range of / g. 4. It has a repeating structural unit represented by the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 dl.
When injection molding of a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin in the range of / g is crystallized in a mold. Thrust washer manufacturing method. 5. A thrust washer obtained by the method according to claim 3.