JPH11124444A - Sliding component consisting of polypropylene terephthalate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sliding component excellent in friction resistance and abrasion resistance especially in dimensional accuracy and noise reduction properties. SOLUTION: This sliding component consists of a polypropylene terephthalate resin composed of a dicarboxylic acid component consisting mainly of terephthalic acid or its derivative and a glycol component consisting mainly of 1,3-propylene glycol. It is preferable that 100 pts.wt. polypropylene terephthalate is further incorporated with 5-100 pts.wt. elastomer having a glass transition temperature of <=20 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sliding parts for automobiles, electric and electronic equipment products, which are excellent in friction and wear resistance, particularly excellent in dimensional accuracy and noise reduction properties when processed into sliding parts.
The present invention relates to a resin suitable as a mechanical mechanism component.

[0002]

2. Description of the Related Art Thermoplastic polyesters represented by polyethylene terephthalate and polybutylene terephthalate are excellent in mechanical properties, heat resistance, chemical resistance, weather resistance, and electrical properties, and are therefore used in a wide range of fields such as automobiles, electric and electronic parts. Used in

In recent years, these resins have tended to be used under more severe conditions, and higher properties are required. As one of such properties, for sliding parts and mechanical parts of automobiles, electric and electronic products, etc., improvement of friction and wear characteristics, long-term sustainability and reduction of friction noise due to sliding, etc. Has been requested.

As a method for improving such required characteristics, for example, Japanese Patent Application Laid-Open No. Hei 6-228417 discloses a method in which silicone oil is blended with polybutylene terephthalate.

[0005]

However, the polybutylene terephthalate resin does not always have sufficient abrasion resistance and has a large molding shrinkage, and thus has a problem in dimensional accuracy when processed into a sliding part. Although the friction and abrasion resistance is improved by blending the silicone oil with the polybutylene terephthalate resin, it does not sufficiently satisfy the recent demands.
When formed into sliding parts such as bearings and keyboard parts, the effect of reducing frictional noise due to sliding was insufficient. Accordingly, it is an object of the present invention to provide a sliding part which has excellent friction and wear resistance and has reduced friction noise caused by sliding when molded into a sliding part.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides (1) a sliding component made of a polypropylene terephthalate resin comprising a dicarboxylic acid component containing terephthalic acid and its derivative as a main component and a glycol component mainly containing 1,3-propylene glycol.
For 100 parts by weight of polypropylene terephthalate resin, an elastomer having a glass transition temperature of
(3) The above sliding component further comprising 100 parts by weight.
(4) A dispersed phase comprising an elastomer having a glass transition temperature of 20 ° C. or less is present in the above-mentioned sliding component wherein the elastomer having a glass transition temperature of 20 ° C. or less is an olefin-based elastomer. (5) The epoxy compound is used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polypropylene terephthalate resin.
(6) The above sliding part further containing a weight part.
The above-mentioned sliding component, wherein the nucleating agent is further contained in an amount of 0.01 to 20 parts by weight with respect to 100 parts by weight of the polypropylene terephthalate resin, (7) the nucleating agent is talc, mica, kaolin, silica, clay (8) the sliding component, wherein the sliding component is one or a mixture of two or more selected from inorganic carboxylate, inorganic sulfonate, metal oxide, carbonate, organic carboxylate, and organic sulfonate; The above-mentioned sliding parts whose parts are automobile parts, electric / electronic equipment parts, office machine parts or miscellaneous goods parts;
The above sliding parts which are gears, bearing parts or keyboard parts.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition of the present invention will be specifically described below.

[0008] The polypropylene terephthalate resin used in the present invention refers to a polypropylene terephthalate resin comprising a dicarboxylic acid component containing terephthalic acid and its derivative as a main component and a glycol component mainly containing 1,3-propylene glycol.

The dicarboxylic acid component is preferably terephthalic acid or an alkyl ester of terephthalic acid.

In addition, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, oxalic acid, adipic acid, 1,4
It is possible to partially use ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, an ethylene oxide adduct of bisphenol-A, or the like as a glycol component. it can.

The copolymerization amount in the case of copolymerization is not particularly limited as long as the object of the present invention is not impaired, but is usually 30 mol% or less of the acid component or 30 mol% of the glycol component.
It is preferably at most mol%.

The method for producing the polypropylene terephthalate resin used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

Although the molecular weight of such a polypropylene terephthalate resin is not particularly limited, it usually has an intrinsic viscosity (dl / g) of 0.10 to 0.10 measured at 25 ° C. using a mixed solution of phenol / tetrachloroethane = 1/1. 3.00 can be used, and preferably 0.25 to 2.0.
50, particularly preferably 0.40 to 2.25.

Further, the sliding component of the present invention, when further added with an elastomer having a glass transition temperature of 20 ° C. or less, can reduce the impact characteristics, the sliding characteristics of the sliding component under high-speed rotation, and the decrease in mechanical strength due to deterioration of the sliding component. Can be improved.

There is no particular limitation as long as the elastomer has a glass transition temperature of not more than 20 ° C., but olefin elastomers, nylon elastomers, polyester elastomers, polyester polyether elastomers, polyester polyester elastomers, polyester polyamide elastomers and the like can be used. Preferred, more preferred are polyester polyether-based elastomers and olefin-based elastomers, and particularly preferred are olefin-based elastomers. Specific examples of such an olefin-based elastomer include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene /
Conjugated diene copolymer, ethylene / ethyl acrylate copolymer, ethylene / methacrylic acid copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, ethylene / ethyl acrylate g-maleic anhydride copolymer, ethylene /
Methyl methacrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleimide copolymer,
Ethylene / ethyl acrylate-g-N-phenylmaleimide copolymer, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g-maleic anhydride copolymer, ethylene / propylene / 1, 4-hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride copolymer, ethylene / propylene / 2,5-norbornadiene-g-maleic anhydride copolymer, ethylene / Hydrogen / propylene-g-N-phenylmaleimide copolymer, styrene / maleic anhydride copolymer, styrene / butadiene / styrene-g-maleic anhydride block copolymer, styrene / butadiene / styrene block copolymer After that, styrene / ethylene obtained by grafting maleic anhydride / Styrene-styrene -g- maleic acid block copolymer, styrene / isoprene -g- maleic acid block copolymer, ethylene / acrylic acid ionomers, ethylene / methacrylic acid ionomer,
Examples thereof include ethylene / itaconic acid ionomers, and these can be used alone or in the form of a mixture.

Such olefin-based elastomers may further have a hydroxyl group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid metal base in a polymer molecule or at a polymer terminal for the purpose of improving the compatibility with the polypropylene terephthalate resin. In addition, a polyolefin elastomer in which at least one kind of functional group among carboxylic acid anhydride group, imide group and the like is chemically bonded can also be used.

[0017] Alternatively, these olefin-based elastomers may be made of acrylic acid, methacrylic acid, or the like at the time of melt-kneading in order to improve the compatibility with polypropylene terephthalate.
Maleic acid, fumaric acid, itaconic acid, crotonic acid, methylmaleic acid, methylfumaric acid, mesaconic acid, citraconic acid, glutaric acid and metal salts of these carboxylic acids, methyl hydrogen maleate, methyl hydrogen itaconate, methyl acrylate, acrylic Ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, Maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo- (2,2,
1) -5-heptene-2,3-dicarboxylic acid, endobicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide,
By adding N-butylmaleimide, N-phenylmaleimide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, glycidyl citraconic acid, etc., the olefin-based elastomer or polypropylene terephthalate can also be chemically modified. it can.

In the present invention, the amount of the elastomer having a glass transition temperature of not higher than 20 ° C. is usually 5 to 100 parts by weight, preferably 10 to 60 parts by weight, more preferably 100 parts by weight of the polypropylene terephthalate resin. Is 15 to 40 parts by weight.

When a relatively small amount of an elastomer is used, the elastomer in the resin composition is present as a dispersed phase in a polypropylene terephthalate resin as a matrix. In order for the molded article obtained by the composition of the present invention to have more excellent impact strength, it is desirable that it is finely dispersed. One of the methods for evaluating the mixing state in the resin composition is a method using the particle size of the dispersed phase as an evaluation scale.When an elastomer is blended in the resin composition of the present invention, the dispersion average of the elastomer portion is determined by the elastomer. Is preferably 20 microns or less, more preferably 1 μm or less.
0 microns or less.

The sliding component of the present invention may further contain an epoxy compound for the purpose of improving the sliding properties, impact resistance and moldability.

The epoxy compound is not particularly limited as long as it is an epoxy compound containing an epoxy group in a molecule.
Triepoxy compounds are preferred, and diepoxy compounds are particularly preferred. Specific examples of such a diepoxy compound include the following general formula (1):
(2), (3), (4), (5), (6), (7),
The diepoxy compound represented by (8) can be used.

[0022]

Embedded image (N represents an integer of 1 or more.)

The amount of the epoxy compound to be added is 100 parts by weight of the polypropylene terephthalate resin.
Usually, it is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, and more preferably 0.2 to 1 part by weight.

Further, when a nucleating agent is further added to the sliding parts of the present invention, the mechanical properties and the dimensional accuracy in forming the sliding parts are remarkably improved.

The nucleating agent of the present invention is not particularly limited as long as it is a compound which promotes the crystallization of a polypropylene terephthalate resin or a polypropylene terephthalate resin composition, but talc, mica, kaolin, silica, clay, inorganic carboxylate, etc. , Inorganic sulfonates, metal oxides, carbonates, organic carboxylates, organic sulfonates and the like are preferably used, among these, talc, mica,
Kaolin can be used particularly preferably.

The amount of the nucleating agent of the present invention is usually 0.00.0 parts by weight per 100 parts by weight of the polypropylene terephthalate resin.
It is 1 to 20 parts by weight, preferably 0.02 to 15 parts by weight, more preferably 0.03 to 10 parts by weight.

In order to further improve the friction and wear characteristics of the sliding parts of the present invention, mineral oils such as spindle oil, turbine oil, cylinder oil, machine oil, refrigerating machine oil, gear oil, polyethylene wax, liquid paraffin, Hydrocarbons such as paraffin wax, lauric acid, behenic acid,
Fatty acids such as montanic acid, hexyl alcohol, diols, glycerin, polyglycerol, alcohols such as pentaerythritol, and alcohols composed of the above fatty acids and alcohols, for example, stearyl stearate, behenyl behenate, pentaerythritol tristearate, penta Fatty acid esters such as erythritol tetrastearate, glycerin monostearate, glycerin monobehenate, palmitylamide, stearylamide, oleylamide, methylenebisstearylamide,
Fatty acid amides such as ethylenebisstearylamide, metal soaps such as magnesium stearate, calcium stearate, barium stearate and zinc stearate, natural waxes such as montan wax, graphite,
Solid lubricants such as molybdenum disulfide and silicone oil, known polymers capable of imparting good fluidity such as polyethylene resins, polytetrafluoroethylene resins, and polyetherester block polymers can be blended.

The sliding component of the present invention may further contain a filler for the purpose of improving mechanical strength and heat resistance. Examples of such a filler include glass fiber, carbon fiber, metal fiber, aramid fiber, asbestos, potassium titanate whisker, aluminum borate whisker, wallastenite, glass flake, glass beads, titanium oxide and aluminum oxide. .

In the above-mentioned filler, glass fibers are preferably used. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing a resin, and for example, it can be selected from long fiber type or short fiber type chopped strand, milled fiber and the like.

The amount of the filler of the present invention is usually 1 to 20 with respect to 100 parts by weight of the polypropylene terephthalate resin.
0 parts by weight, preferably 5 to 150 parts by weight, more preferably 10 to 100 parts by weight.

Further, the sliding component of the present invention includes an antioxidant such as a hindered phenol-based, phosphorus-based, and sulfur-based antioxidant and a heat stabilizer, as long as the object of the present invention is not impaired.
UV absorbers (eg resorcinol, salicylate,
Benzotriazole, benzophenone, etc.), coloring inhibitors (phosphites, hypophosphites, etc.), plasticizers, flame retardants, plasticizers, release agents, antistatic agents, and coloring agents including dyes and pigments ( One or more conventional additives such as cadmium sulfide, phthalocyanine and the like can be added.
The resin composition of the present invention is usually produced by a known method. For example, it is prepared by feeding a polypropylene terephthalate resin, a filler and other necessary additives to an extruder or the like with or without premixing, and sufficiently melting and kneading in a temperature range of 230 ° C to 280 ° C. .
In this case, for example, a single-screw extruder, a twin-screw extruder, a kneader of a kneader type or the like equipped with a “unimelt” type screw can be used. It is preferable to use several elements by inserting or not inserting them.

The sliding part of the present invention can be easily obtained by injection molding the above-mentioned polypropylene terephthalate resin or polypropylene terephthalate resin composition.

The sliding parts made of the polypropylene terephthalate resin of the present invention are excellent in sliding properties and noise reduction properties, and thus are suitable for sliding parts of automobiles, electric / electronic devices, office machines, miscellaneous goods, etc. Suitable for bearings and keyboard parts. Gears may not be included in the category of sliding parts. However, in actuality, sliding characteristics are required in view of the fact that there is a slight play in gear engagement. Shall be handled as moving parts.

[0034]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

<< Evaluation Items >> Various characteristics described in Examples and Comparative Examples were measured by the following methods.

Molding of sample for evaluation of dynamic wear characteristics: Resin pellets were converted to Sumitomo Nestal injection molding machine Promat 40
/ 25 (manufactured by Sumitomo Heavy Industries, Ltd.), and each molded product was obtained by injection molding.

Dynamic wear characteristics: Using a Suzuki friction wear tester, load 5 kg, linear velocity 200 mm / sec, pulley system 60.15 mm, tangent center 17.8 mm, same material as mating material, 60 minutes After sliding, the load on the chart was measured, and the dynamic friction coefficient (μ) was measured by the following equation. Further, the specific wear amount was measured from the initial weight of the test piece and the weight after the test, and the wear amount per time was calculated from the following equation.

Dynamic friction coefficient (μ) = (Pulley diameter × load on chart) / (contact center circle × load) (Pulley diameter: 60.15 mm, contact circle center: 17.8)
mm, load on the chart: measured value) Specific wear (mm ³ / kgf · km) = (wear weight (mg) / density (g / cm ³ )) / (sliding distance × load): (sliding distance = 20
m / min × 60 minutes) Abrasion amount per hour (μm / h) = specific abrasion amount × 60 minutes ×
Load × speed (m / min) × 10 ⁻² << Evaluation of sliding parts (gears) >> ・ Pellet is supplied to Sumitomo Nestal injection molding machine Promat (manufactured by Sumitomo Heavy Industries, Ltd.), and cylinder temperature is 280.
℃, mold temperature 80 ℃, pitch circle diameter 42mm,
A module 1.0, a gear having a thickness of 8 mm was formed at a four-point gate. The roundness of this gear was measured by a roundness measuring device manufactured by Tokyo Seimitsu Co., Ltd.

The two gears thus obtained were moved at a linear speed of 200 mm.
/ Sec, the squeak sound when rotated for 200 hours was evaluated according to the following criteria.

No squeak sound: 、, slight squeak sound: Δ, squeak sound: x.

Reference Example 1 Production of polypropylene terephthalate 2.0 kg of terephthalic acid was placed in a 5 liter autoclave.
1.3 kg of 1,3-propylene glycol was weighed, and the internal temperature of the autoclave was set at 180 ° C. When the internal temperature reached 120 ° C., 2.0 g of tetrabutyl titanate and 2.0 g of monohydroxytin oxide were added.
Stirred at 0 ° C. for 1 hour. Then 250 ° C over 2 hours
At the same time, the pressure was reduced to 0.5 mmHg. Thereafter, the reaction was carried out for about 1 hour, and when the torque became constant, the polymer was discharged. The intrinsic viscosity measured at 25 ° C. using a mixed solvent of phenol / tetrachloroethane = 1/1 was 1.3.

The thermoplastic polyester resin and other additives used in the examples are as follows.

Polybutylene terephthalate (PB)
T): Toray PBT1100S (manufactured by Toray Industries, Inc.) was used.

Polyethylene terephthalate (PE
T): PET having an intrinsic viscosity of 0.65 (25 ° C., 1: 1 mixed solution of phenol / tetrachloroethane) was used.

Nylon 6: "Amilan" CM1010
(Manufactured by Toray Industries, Inc.).

Example 1, Comparative Examples 1 to 4 Resin pellets were mixed with Sumitomo Nestal injection molding machine Promat 4
0/25 (manufactured by Sumitomo Heavy Industries, Ltd.), and each molded product was obtained by injection molding.

A gear as an example of a sliding part was formed by the above-described method, and the roundness and the squeaking noise during rotation were observed.

Table 1 shows the results.

[0049]

[Table 1]

From the measurement results of Example 1 and Comparative Examples 1 to 3,
Polypropylene terephthalate resin has excellent sliding properties,
It can be seen that the amount of wear is small. Further, it can be seen that the roundness of the gear is excellent and the squeak noise when the gear rotates is small.

On the other hand, PBT and PE were obtained from Comparative Examples 1, 2, and 3.
At T and N6, it can be seen that the sliding characteristics, the amount of wear, the roundness, and the gear squeaking noise are large.

Examples 2 to 4 The polypropylene terephthalate resin obtained in Reference Example and other additives were melt-kneaded at 280 ° C. using a 30 mm φ twin screw extruder with L / D = 45 to form pellets.

In Example 2, 20 parts by weight of an elastomer having a glass transition temperature of 20 ° C. or less: glycidyl methacrylate-modified copolymerized polyethylene (“Bond First” EPX-6, manufactured by Sumitomo Chemical Co., Ltd.) was added to 100 parts by weight of polypropylene terephthalate. .

In order to measure the dispersed particle size of the elastomer in the obtained resin composition, a thin piece was cut out from a test piece for evaluation using an ultramicrotome, and this was cut with an optical microscope (transmitted light) and a transmission electron microscope. Photographs were taken using a microscope, the major axis of 100 individuals selected at random from the micrograph was measured, and the average value was calculated. As a result, the dispersed particle size of the elastomer in the resin composition was extremely finely dispersed at 1.6 μm or less.

In Example 3, a diepoxy compound represented by the following general formula (1) was replaced with polypropylene terephthalate 10
1 part by weight was added to 0 part by weight.

[0056]

Embedded image

In Example 4, a crystal nucleating agent: talc “LMS-
300 "(manufactured by Fuji Talc) was added in an amount of 0.3 part by weight based on 100 parts by weight of polypropylene terephthalate.

Comparative Examples 4 to 6 PBT resin and other additives were mixed with L / D = 45 at 30 mm
The mixture was melt-kneaded at 280 ° C. using a φ2 screw extruder to form pellets.

In Comparative Example 4, 20 parts by weight of an elastomer having a glass transition temperature of 20 ° C. or less: glycidyl methacrylate-modified copolymerized polyethylene (“Bond First” EPX-6, manufactured by Sumitomo Chemical Co., Ltd.) was added to 100 parts by weight of the PBT resin. .

Incidentally, in order to measure the dispersed particle size of the elastomer in the obtained resin composition, a thin piece was cut out from a test piece for evaluation using an ultramicrotome, and this was cut with an optical microscope (transmitted light) and a transmission electron microscope. Photographs were taken using a microscope, the number of individuals randomly selected from the micrographs was measured, and the average value was calculated. As a result, the dispersed particle size of the elastomer in the resin composition was extremely finely dispersed at 1.6 μm or less.

In Comparative Example 5, 1 part by weight of the same diepoxy compound as in Example 3 was mixed with 100 parts by weight of the PBT resin.

In Comparative Example 6, a nucleating agent: talc “LMS-
300 "(manufactured by Fuji Talc) was added in an amount of 0.3 part by weight based on 100 parts by weight of the PBT resin.

Table 2 shows a series of formulas and results.

[0064]

[Table 2]

As shown in Examples 2, 3 and 4, the polypropylene terephthalate resin had a glass transition temperature of 20 ° C.
It can be seen that the addition of the following elastomer, epoxy compound, or crystal nucleating agent further improves the sliding characteristics, the roundness of the gear, and the squeal of the gear. In particular, in Example 4 in which talc was blended as a crystal nucleating agent, the amount of wear can be specifically reduced. On the other hand, as shown in Comparative Examples 4 to 6, PB
It can be seen that the effect of improving the sliding properties is small even when an elastomer, an epoxy compound or a nucleating agent having a glass transition temperature of 20 ° C. or less is added to T in the same manner.

[0066]

The sliding parts of the present invention are excellent in friction resistance and abrasion properties, and particularly excellent in dimensional accuracy and noise reduction properties when processed into sliding parts.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C08L 67/02 23:00)

Claims (9)

[Claims] 1. A sliding part comprising a polypropylene terephthalate resin comprising a dicarboxylic acid component mainly composed of terephthalic acid and a derivative thereof and a glycol component mainly composed of 1,3-propylene glycol. 2. Polypropylene terephthalate resin 100
2. The composition according to claim 1, further comprising 5 to 100 parts by weight of an elastomer having a glass transition temperature of 20 DEG C. or less based on parts by weight.
The sliding parts described. 3. The sliding part according to claim 2, wherein the elastomer having a glass transition temperature of 20 ° C. or lower is an olefin elastomer. 4. The slide according to claim 2, wherein a dispersed phase comprising an elastomer having a glass transition temperature of 20 ° C. or less is present in the polypropylene terephthalate resin matrix phase, and the average particle size of the dispersed phase is 20 μm or less. Moving parts. 5. Polypropylene terephthalate resin 100
The sliding component according to any one of claims 1 to 4, further comprising 0.01 to 5 parts by weight of an epoxy compound based on parts by weight. 6. Polypropylene terephthalate resin 100
The sliding component according to any one of claims 1 to 5, further comprising 0.01 to 20 parts by weight of a nucleating agent based on part by weight. 7. The nucleating agent is talc, mica, kaolin, silica, clay, inorganic carboxylate, inorganic sulfonate,
The sliding component according to claim 6, wherein the sliding component is one or a mixture of two or more selected from a metal oxide, a carbonate, an organic carboxylate, and an organic sulfonate. 8. The sliding part according to claim 1, wherein the sliding part is an automobile part, an electric / electronic device part, an office machine part, or a miscellaneous goods part. 9. The sliding part according to claim 1, wherein the sliding part is a gear, a bearing part or a keyboard part.