JP2001302878A - Phenol resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phenol resin molding material excellent in long-term heat resistance and dimensional stability. SOLUTION: This phenolic resin molding material is characterized in that the resin component thereof is a phenolic resin obtained by compounding novolak-type phenol resin and resol-type phenol resin in a weight ratio within the range of (90/10) to (60/40) and the molding material is obtained by compounding melamine in an amount of 15-60 pts.wt. and an inorganic filler in an amount of 160-250 pts.wt. based on the 100 pts.wt. of the phenolic resin and compounding hexamethylenetetramine in an amount of 10-20 pts.wt. based on the 100 pts.wt. of the novolak-type phenolic resin, and contains at least a glass fiber as the inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenolic resin molding material having excellent long-term heat resistance and dimensional stability and suitable mainly for replacing various metal parts such as automobile parts.

[0002]

2. Description of the Related Art Hitherto, phenolic resin molding materials have been widely used in various fields as materials excellent in balance among heat resistance, dimensional stability, mechanical strength and cost. However, the characteristics required in the market are becoming more and more severe, and in particular, in recent years, in the automotive industry, there has been a demand for replacing plastics such as transmission parts used in high-temperature atmospheres and parts near the engine with conventional ones. The reality is that the heat resistance of phenolic resin molding materials has reached its limit.

As a solution to this problem, the present applicant has filed an application for a phenolic resin molding material which is excellent in long-term heat resistance by blending melamine with a novolak-type phenolic resin (Japanese Patent Application No. Hei.
0-323470).

[0004]

However, the above molding material suffers from poor initial dimensions due to a large expansion of the molded product which is considered to be based on the interaction between melamine and hexamethylenetetramine during after-curing. And metal insert molded articles are liable to cracks, which limits the use and field.

The present invention overcomes the drawbacks of the conventional phenolic resin molding material, has moldability equivalent to that of the conventional material, is excellent in long-term heat resistance and mechanical strength, and has a dimension in after-cure. The object of the present invention is to provide a phenolic resin molding material having excellent stability.

[0006]

The present inventors have conducted intensive studies to develop a phenolic resin molding material having the above-mentioned preferable properties.
It has been found that the object can be achieved by blending a resole-type phenol resin and melamine in a specific ratio and using hexamethylenetetramine as a curing agent, and based on this finding, completed the invention.

That is, according to the present invention, the phenolic resin molding material comprises a novolak type phenolic resin and a resol type phenolic resin in a weight ratio of 90/10 to 60/40.
Wherein the phenolic resin is blended in an amount of 15 to 60 parts by weight of melamine and 160 to 250 parts by weight of an inorganic filler with respect to 100 parts by weight of the phenol resin. The first feature is to mix 10 to 20 parts by weight of methylenetetramine, and the second feature is that at least glass fiber is contained as the inorganic filler.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The novolak-type phenolic resin of the present invention is obtained by condensing phenols and aldehydes in the presence of an acid catalyst. Any one of the novolak type phenol resins conventionally used in molding materials can be appropriately selected and used.

The resole type phenol resin in the present invention may be either a methylol type or a dimethylene ether type, and may be liquid or solid.

In the present invention, a novolak type phenol resin and a resol type phenol resin are used in combination as a resin component, and both are blended in a weight ratio of 90/10 to 60/40. If the ratio of the resole type phenolic resin is less than this range, heat resistance and mechanical strength become insufficient,
If the amount exceeds this range, the dimensional stability during after-curing deteriorates.

In the present invention, it is necessary to use melamine. This melamine is a phenolic resin 100
It is blended in a ratio of 15 to 60 parts by weight with respect to parts by weight. 1
If the amount is less than 5 parts by weight, the effect of improving long-term heat resistance is not sufficiently exhibited, and dimensional stability in after-curing cannot be obtained. On the other hand, if it exceeds 60 parts by weight, the mechanical strength is reduced, the dimensional stability in after-cure cannot be obtained, and the workability at the time of molding material production deteriorates. In consideration of long-term heat resistance, mechanical strength, dimensional stability during after-curing, workability during molding material production, and the like, the preferred amount of melamine is 25 to 50 parts by weight.

The inorganic filler in the present invention is not particularly limited, and may be appropriately selected from spherical fillers, plate-like fillers, fibrous fillers and the like conventionally used as inorganic fillers in phenolic resin molding materials. Can be. Examples of the spherical filler include calcium carbonate, barium sulfate, calcium sulfate, clay, perlite, shirasu balloon, diatomaceous earth, calcined alumina,
Examples thereof include calcium silicate, and examples of the plate-like filler include talc and mica. On the other hand, examples of the fibrous filler include glass fiber, carbon fiber, boron fiber, silicon carbide fiber, and potassium titanate fiber. These inorganic fillers may be used alone,
Although two or more kinds may be used in combination, a glass fiber-based material is particularly preferable in terms of strength, heat resistance, cost, and the like. This glass fiber is desirably subjected to a surface treatment such as a silane coupling agent for the purpose of improving the adhesion to the phenol resin.

As the silane coupling agent, those applied to glass fibers used in conventional phenolic resin molding materials, for example, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) Ethyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-
β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ
-Chloropropyltrimethoxysilane and the like. Among these, amino-based silanes and epoxy-based silanes are particularly preferred from the viewpoints of mechanical strength, heat resistance, workability in manufacturing the molding material, and the like of the obtained molding material.

In the present invention, it is necessary to mix the inorganic filler in an amount of 160 to 250 parts by weight based on 100 parts by weight of the phenol resin. This amount is 160
If the amount is less than parts by weight, sufficient mechanical strength and heat resistance cannot be obtained, and if it exceeds 250 parts by weight, workability during production of a molding material and moldability of the present material deteriorate. In consideration of mechanical strength, heat resistance, moldability, and the like, the preferred amount of the inorganic filler is in the range of 180 to 220 parts by weight. Also,
The glass fiber content in the inorganic filler is preferably at least 50%.

In the present invention, hexamethylenetetramine is preferably used in an amount of 10 to 20 parts by weight based on 100 parts by weight of the novolak type phenol resin. If the amount is less than 10 parts by weight, the curing becomes insufficient and causes a decrease in strength. On the other hand, when the amount is more than 20 parts by weight, the workability at the time of manufacturing the molding material is deteriorated.

The molding material of the present invention may optionally contain various additives conventionally used in phenolic resin molding materials, for example, a release agent such as calcium stearate, a hardening accelerator such as magnesium oxide, a hindered phenol-based compound. Antioxidants, hindered amine light stabilizers,
A benzotriazole-based ultraviolet absorber and a coloring agent can be added.

The phenolic resin molding material of the present invention can be produced by heating and kneading with a pressure kneader, a twin-screw extruder, a Henschel mixer, a mixing hot roll and the like, and pulverizing.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the performance of the obtained molding material was evaluated according to the following method.

(1) Flexural strength and flexural modulus The flexural strength and flexural modulus were measured according to JIS K6911. (2) Charpy impact strength Charpy impact strength was measured according to J1S K6911. (3) Dimensional change rate during after cure According to J1S K6911, the shrinkage rate before and after after cure was measured, and the dimensional change rate was calculated. (4) Long-term heat resistance After holding the after-cured bending test specimen at 250 ° C. for 500 hours, the bending strength and the bending elastic modulus were measured in the same manner as in (1) above, and the respective holding rates were calculated. The weight change rate was determined.

Example 1 Novolak resin (manufactured by Asahi Organic Materials Co., Ltd., number average molecular weight 800) 87 parts by weight, dimethylene ether type resole resin [Asahi Organic Materials Co., Ltd., number average molecular weight 700] 13
33 parts by weight of melamine (manufactured by Mitsui Chemicals, Inc.), 167 parts by weight of glass fiber [manufactured by NEC Corporation], 167 parts by weight, clay 33
Parts by weight, 12 parts by weight of hexamethylenetetramine, 5 parts by weight of magnesium oxide, and 5 parts by weight of calcium stearate were mixed, kneaded by a mixing hot roll, and pulverized by a power mill to produce a molding material. The obtained molding material is injection-molded under the following conditions: cylinder temperature: front 90 ° C., rear 50 ° C. mold temperature: 175 ° C. curing time: 60 seconds, JIS bending test piece, J1S Charpy impact test piece, and JIS molding shrinkage. Test pieces were prepared.
About the obtained test piece, 180 degreeC x 3 hours +220 degreeC
After-cure was performed under the conditions of × 3 hours, and the bending strength, the Charpy impact strength and the flexural modulus were measured, and the dimensional stability in the after-cure was evaluated. Further, the bending test piece after the after-curing was set at 250 ° C. × 50.
A 0 hour long-term heat test was performed. Table 1 shows the results.

Example 2 and Comparative Examples 1 to 3 The same procedure as in Example 1 was carried out except that the mixing ratio was changed as shown in Table 1, and after producing a molding material, each test piece was prepared. Was evaluated. Table 1 shows the results.

[0022]

[Table 1]

As can be seen from Table 1, the molded article using the phenolic resin molding material of the present invention has a dimensional change rate of 1/100 that of the comparative example in a dimensional stability test by after-cure.
It is as small as 5 to 1/10, indicating that the dimensional change due to after-curing is extremely small. Further, in the long-term heat resistance evaluation test, the flexural strength, the decrease in the retention of flexural modulus and the rate of change in weight are smaller than those of the comparative examples, and the long-term heat resistance is excellent.

The results of evaluating the performance of the test piece by the procedure shown in Example 1 when a melamine resin is blended in place of melamine in the phenolic resin molding material of the present invention are shown as reference examples.

[0025]

[Table 2]

When the physical properties shown in Example 2 and Reference Example in Table 1 are compared, the mechanical strength and heat resistance of the phenolic resin molding material of the present invention are much superior to those of the Reference Example. You can see that there is. That is, it is apparent that the object of the present invention is not achieved by using a melamine resin.

[0027]

According to the phenolic resin molding material of the present invention, the dimensional change due to after-curing is extremely small.
Since a molded article excellent in long-term heat resistance in a high temperature atmosphere exceeding 0 ° C. can be obtained, it is suitable as a substitute material for metal of automobile parts such as a transmission and an engine.

Claims (2)

[Claims] 1. A resin component comprising a novolak phenol resin and a resol phenol resin in a weight ratio of 90/10 to 6
A phenolic resin blended in the range of 0/40, wherein 100 parts by weight of the phenolic resin is 15 to 15 parts by weight of melamine.
A phenolic resin molding material comprising 60 parts by weight, 160 to 250 parts by weight of an inorganic filler, and 10 to 20 parts by weight of hexamethylenetetramine per 100 parts by weight of a novolak-type phenolic resin. 2. The phenolic resin molding material according to claim 1, wherein the inorganic filler contains at least glass fiber.