JP2001247757A - Sliding unsaturated polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unsaturated polyester resin composition which maintains the excellent characteristics, such as dimensional accuracy, mechanical strength, moldability, heat resistance, and flame retardancy, of conventional unsaturated polyester molding materials and has high sliding characteristics and high abra sion resistance. SOLUTION: This sliding unsaturated polyester resin composition is characterized by comprising 50 to 600 pts.wt. of a filler, 5 to 20 pts.wt. of an organic fluorocompound, and 100 pts.wt. of the combination of a cross-linking agent with an unsaturated polyester in which the rate of the total amount of cyclic skeleton-having polyhydric alcohol residues and cyclic skeleton-having saturated/ unsaturated polybasic acid residues to the total amount of polyhydric alcohol residues and saturated/unsaturated polybasic acid residues is <=8 mol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an unsaturated polyester resin composition for a sliding member.

[0002]

2. Description of the Related Art Unsaturated polyester resin molding materials (bulk molding compounds) have conventionally been used in OA equipment, office equipment chassis, etc. due to their excellent dimensional accuracy, flame retardancy, heat resistance, mechanical strength, and moldability. Accuracy is strict,
Widely used in fields where flame retardancy is required.

However, the conventional unsaturated polyester resin molding material can produce a molded product excellent in dimensional accuracy, flame retardancy, mechanical strength, and heat resistance by curing molding,
There was a problem that the slidability was not good. Conventionally, as a means to improve the wear resistance and slidability of thermosetting resin,
A method of adding potassium titanate and polyolefin powder (JP-A-8-231859) and a method of adding tetrafluoroethylene resin powder (JP-A-51-818)
No. 52), a method of adding polyethylene (Japanese Unexamined Patent Publication No.
1-89546, JP-A-58-63752) and the like have been proposed. As a method of blending fine reinforcing fibers into a part of the filler, asbestos,
It has been proposed to add potassium titanate, wollastonite, and the like, and it is also known that potassium titanate can improve the slidability and abrasion resistance (JP-A-58-76413). Gazette, JP-A-59-176
313, JP-A-62-43454). However, in these conventional methods, a composition which can satisfy a high degree of sliding characteristics and abrasion resistance required when used as a sliding member still has problems in formability and mechanical strength. Attempts to improve could not satisfy the high sliding properties and abrasion resistance.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides dimensional accuracy, mechanical strength, moldability, heat resistance, and the like of conventional unsaturated polyester molding materials.
An object of the present invention is to provide an unsaturated polyester resin composition having high sliding properties and abrasion resistance while maintaining excellent properties such as flame retardancy.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object, and as a result, have found that the cyclic skeleton has been reduced to 8
By adding an organic fluorine-based compound at a specific ratio to an unsaturated polyester having a mole percentage or less and a cross-linking agent, it has excellent slidability and abrasion resistance and excellent dimensional accuracy.
The inventors have found that an unsaturated polyester resin composition having mechanical strength, moldability, heat resistance, flame retardancy and the like can be obtained, and have completed the present invention.

That is, the present invention provides a polyhydric alcohol residue having a cyclic skeleton and a saturated / unsaturated polybasic acid residue having a cyclic skeleton with respect to the sum of the polyhydric alcohol residue and the saturated / unsaturated polybasic acid residue. Of inorganic filler 50 to 600 parts by weight and organofluorine compound 5 to 20 parts by weight with respect to 100 parts by weight of the total amount of unsaturated polyester having a total ratio of 8 mol% or less and a crosslinking agent. An object of the present invention is to provide a slidable unsaturated polyester resin composition characterized by the following.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The unsaturated polyester used in the present invention is obtained by polycondensing a polyhydric alcohol with an unsaturated polybasic acid and, if necessary, a saturated polybasic acid. Examples of the polyhydric alcohol constituting the unsaturated polyester used in the present invention include ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neopentanediol, and the like.
Glycerin and the like are indicated.

The unsaturated polybasic acids constituting the unsaturated polyester used in the present invention include maleic anhydride,
Examples of fumaric acid, citraconic acid, itaconic acid and the like, and examples of the saturated polybasic acid include heptic acid, succinic acid, adipic acid and sebacic acid.

The unsaturated polyester used in the present invention is obtained by polycondensing the above-mentioned polyhydric alcohol having no cyclic skeleton at all and unsaturated / saturated polybasic acid having no cyclic skeleton at all. Or a polyhydric alcohol having a cyclic skeleton and / or a saturated / unsaturated polybasic acid having a cyclic skeleton is converted into a polyhydric alcohol residue and a saturated / unsaturated polybasic acid.
The total ratio of the polyhydric alcohol residue having a cyclic skeleton and the saturated / unsaturated polybasic acid residue having a cyclic skeleton to the total of the unsaturated polybasic acid residues is 8 mol% or less, preferably 4 mol% or less.
It may be obtained by polycondensation using an amount of not more than mol%.

In the present invention, the cyclic skeleton means an aromatic ring and an alicyclic ring. Examples of the polyhydric alcohol having a cyclic skeleton include hydrogenated bisphenol A and bisphenol A, and examples of the saturated polybasic acid include phthalic anhydride, isophthalic acid, terephthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and endo. And methylenetetrahydrophthalic anhydride.

As the cross-linking agent, an appropriate one can be used as long as it has a polymerizable double bond capable of polymerizing with the unsaturated polyester. Such materials include, for example, styrene monomer, diallyl phthalate monomer, diallyl phthalate prepolymer, methyl methacrylate, triallyl isocyanurate and the like. The amount used is 25 to 70 parts by weight, preferably 35 to 6 parts by weight, per 100 parts by weight of the unsaturated polyester and the crosslinking agent.
5 parts by weight.

The organic fluorine-based compound used in the present invention is not particularly limited as long as it has a maximum particle diameter of 100 μm or less, preferably 10 μm or less in the case of powder. If the maximum particle size exceeds 100 μm, a smooth molded product surface cannot be obtained. With a maximum particle size of 10 μm or less, the smoothest molded product surface can be obtained. Moreover, a liquid thing can also be used.

As the organic fluorine compound, for example, tetrafluoroethylene, polytetrafluoroethylene,
Polyvinylidene fluoride, vinylidene fluoride, tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer,
Examples include, but are not limited to, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer.

The amount of the organic fluorine-based compound used in the present invention may be a total amount of the unsaturated polyester and the crosslinking agent of 1
The amount is preferably 5 to 20 parts by weight, more preferably 8 to 15 parts by weight, based on 00 parts by weight. When the organic fluorine-based compound is a powder, if the added amount exceeds 20 parts by weight, the viscosity of the material increases, and the fluidity in the mold at the time of molding is significantly deteriorated. Inconvenience occurs. On the contrary, when the amount is less than 5 parts by weight, the slidability of the obtained molded product is deteriorated. Also, in the case of a liquid, if the addition amount exceeds 20 parts by weight, the fluidity in the mold at the time of molding is significantly deteriorated, or the appearance of the obtained molded product is significantly deteriorated. The slidability of the obtained molded product is deteriorated.

The unsaturated polyester resin composition of the present invention comprises a low-shrinkage agent, a curing agent, a filler, a release agent, a thickener, a fiber reinforcing material, a pigment, etc., in addition to the above components. Can be used as needed within a range that does not impair the purpose.

The low-shrinkage agent is not particularly limited and may be various. For example, polystyrene, polymethyl methacrylate, polyvinyl acetate, saturated polyester, styrene-butadiene rubber and the like are commonly used as low-shrinkage agents. Thermoplastic polymers, which may be used alone or in combination of two or more.

As the curing agent that can be used in the present invention, generally, an organic peroxide can be used, for example, t-butyl peroxyoctoate; benzoyl peroxide; 1,1-di-t-butyl peroxy. Oxy-3,3,5-
Trimethylcyclohexane; t-butyl peroxyisopropyl carbonate; t-butyl peroxybenzoate; dicumyl peroxide; di-t-butyl peroxide and the like. The amount used can be appropriately determined in consideration of the pot life and curability of the unsaturated polyester resin.

As the filler, for example, inorganic powders such as aluminum hydroxide, calcium carbonate, silica, alumina, mica, barium sulfate, clay and talc can be used in an appropriate ratio. As the release agent, for example, stearic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, carnauba wax and the like can be used in an appropriate ratio. Examples of the thickener include metal oxides such as magnesium oxide, magnesium hydroxide, calcium hydroxide, and calcium oxide, and isocyanate compounds. Thickeners need not necessarily be used.

As the fiber reinforcing material, a fiber length of 1.5 to 25
Chopped strand glass cut to about mm, or organic and inorganic fibers such as pulp fiber, Tetron (registered trademark) fiber, vinylon fiber, carbon fiber, aramid fiber, and wollastonite can be used in an appropriate ratio.

The method for producing the unsaturated polyester resin composition of the present invention constituted by the above components is not particularly limited. A desired molded product can be obtained from these unsaturated polyester resin compositions by any of compression molding, transfer molding, and injection molding. The obtained molded article shows excellent sliding properties, wear resistance and moldability, and is also excellent in dimensional accuracy, mechanical strength, heat resistance, flame retardancy and the like.

[0021]

The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

Examples 1 to 7 and Comparative Examples 1 to 6 The respective components having the composition shown in Table 1 were kneaded using a double bowl type kneader to obtain an unsaturated polyester resin composition. The unsaturated polyester used here has the following constitution. A styrene monomer was used as a cross-linking agent, and polytetrafluoroethylene powder was used as an organic fluorine-based compound.

Unsaturated polyester having no cyclic skeleton A: fumaric acid / propylene glycol = 100 mol / 1
00 mol (used as a solution consisting of 73% by weight of this unsaturated polyester and 27% by weight of styrene monomer as a cross-linking agent) B: maleic anhydride / propylene glycol / dipropylene glycol / neopentyl glycol = 100 mol / 25 mol / 45 mol / 30 moles (65% by weight of the unsaturated polyester and 35 styrene monomers as a crosslinking agent)
used as a solution consisting of wt%)

Unsaturated polyester having a cyclic skeleton C: phthalic acid / maleic anhydride / propylene glycol = 30 mol / 70 mol / 100 mol (70% by weight of this unsaturated polyester and styrene monomer 3 as a crosslinking agent)
D: isophthalic acid / maleic anhydride / propylene glycol = 25 mol / 70 mol / 100 mol (used as a solution composed of 60 wt% of this unsaturated polyester and 40 wt% of styrene monomer as a cross-linking agent) E: fumaric acid / propylene glycol / hydrogenated bisphenol A = 100 mol / 80 mol / 20 mol (used as a solution comprising 70% by weight of this unsaturated polyester and 30% by weight of styrene monomer as a crosslinking agent)

The unsaturated polyester resin compositions shown in Table 1 were tested and evaluated for abrasion resistance, molding shrinkage, and surface properties by the following methods. The results are shown in Table 1. (1) Abrasion resistance Among the abrasion tests specified in JIS-K7218, a hollow cylindrical test piece of method A was molded at a molding temperature of 150 ° C. and an injection pressure of 70 M.
Transfer molding with Pa, molding time 2 minutes, JIS-
The specific wear amount was calculated based on K7218 (pv value = 7
50 kPa · m / s partner material; S45C).

(2) Molding Shrinkage Ratio A shrinking disk specified in JIS-K6911 is molded at a molding temperature of 1
Compression molding was performed at 50 ° C., a molding pressure of 10 MPa, and a molding time of 3 minutes, and the molding shrinkage was calculated based on JIS-K6911.

(3) Surface properties (3) -1 Evaluation by flat plate A flat plate having a size of 320 × 220 mm and a thickness of 3 mm was formed by compression molding at a molding temperature of 150 ° C., a molding pressure of 10 MPa and a molding time of 3 minutes, and the leveling and gloss were measured. It was evaluated visually. (3) -2 Evaluation using test box Test box (360) as shown in FIGS.
× 120 × 25mm, wall thickness: long side 4mm, short side 5m
m, bottom surface 3mm), molding temperature 160 ° C, injection pressure 30M
Pa, Injection molding machine NNT2 made by Niigata Iron Works in 2 minutes
Injection molding was performed using 50PSCH7000, and the obtained molded product was visually evaluated for leveling, gloss, and filling property. In addition, these surface characteristics are evaluated based on the following criteria and are shown in Table 1. : Very good ○: good △: slightly poor ×: bad

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

As shown in Table 1, from the unsaturated polyester resin compositions obtained in the examples, molded articles having excellent abrasion resistance, a small molding shrinkage, and excellent surface properties were obtained. Was. In addition, minus sign (-) of molding shrinkage
Indicates expansion with respect to the mold. On the other hand, the molded article of the comparative example produced from the resin composition using the unsaturated polyester having more than 8 mol% of the cyclic skeleton has reduced abrasion resistance, and the compounding amount of the polytetrafluoroethylene powder is as described above. When it exceeds the specific range, the fluidity is remarkably deteriorated so that kneading and production cannot be performed, the molding shrinkage ratio is increased, and the surface characteristics are remarkably deteriorated. Conversely, when the amount was insufficient, the abrasion resistance was significantly reduced.

[0032]

EFFECTS OF THE INVENTION The slidable unsaturated polyester resin composition according to the present invention has a high degree of sliding properties and abrasion resistance, cannot be obtained by conventional techniques, has good moldability, and has excellent surface properties. Therefore, it can be widely used as a molding material which is extremely useful for molding parts requiring particularly high abrasion resistance, for example, parts requiring dimensional accuracy such as chassis of electric parts, cams, cylinders and the like. .

[Brief description of the drawings]

FIG. 1 is a plan view of a test box used for a test.

FIG. 2 is a sectional view taken along line A-A 'in FIG.

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Claims (3)

[Claims] 1. The ratio of the total of polyhydric alcohol residues having a cyclic skeleton and saturated / unsaturated polybasic acid residues having a cyclic skeleton to the sum of polyhydric alcohol residues and saturated / unsaturated polybasic acid residues. Is less than or equal to 8 mol%, and the filler is added to 100 parts by weight of the total amount of the unsaturated polyester and the crosslinking agent.
A slidable unsaturated polyester resin composition, which comprises -600 parts by weight and 5-20 parts by weight of an organic fluorine compound. 2. The slidable unsaturated polyester resin composition according to claim 1, wherein the unsaturated polyester has no cyclic skeleton. 3. An organic fluorine compound having a maximum particle size of 100 μm.
The slidable unsaturated polyester resin composition according to claim 1, which is a powder having a particle size of not more than m.