JPH1053692A - Phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pheniolic resin molding material affording excellent mechanical strength, wear resistance and dimensional stability, and capable of suppressing its swelling due to moisture or oil absorption, blended with glass fibers, an organic natural material, fine silica particles and a lubricant thermoplastic resin in specified proportions. SOLUTION: This phenolic resin molding material contains 60-70wt.% of a total of (A) glass fibers, (B) an organic natural material (e.g. deseggregated pulp, raw pulp, powdered pulp, ground cloth, each <=0.1mm in fiber length), (C) fine silica particles (e.g. synthetic noncrystalline silica <=20μm in secondary agglomerated particle size), and (D) a lubricant thermoplastic resin (e.g. polyolefin resin, fluororesin). In this case, the respective proportions of the components A to D, based on the total amount of these components, are 75-93wt.%, 1-5wt.%, 5-15wt.%, and 1-5wt.%, respectively. It is preferably that 100 pts.wt. of this molding material contains 20-35 pts.wt. of phenolic resins containing 5-20 pts.wt. of a xylene-molding novolak-type pheniolic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin molding material which is excellent in strength and wear resistance, has small swelling due to oil absorption and water absorption, and has excellent dimensional stability. It can be suitably used for mechanical parts.

[0002]

2. Description of the Related Art In recent years, glass fiber-filled phenols having excellent strength, heat resistance, dimensional stability, stress relaxation properties, etc. in accordance with the demand for miniaturization, weight reduction and high performance of structural and mechanical parts such as automobiles and electric parts. Resin molding materials are attracting attention as metal substitute materials. However, glass fibers have an excellent effect on improving strength and heat resistance, but wear properties decrease in inverse proportion to the amount of glass fiber added.

[0003] On the other hand, it has been conventionally known that the blending of organic natural fibers such as pulp and crushed cloth improves wear characteristics. On the other hand, heat resistance and strength, which are the characteristics of phenolic resin molding materials added with glass fibers, are known. Etc. were inevitable. Therefore, by blending organic natural fibers, silica powder, and thermoplastic resin as a filler, heat resistance,
It has been found that the wear characteristics can be improved without impairing the strength (Japanese Unexamined Patent Publication No. Sho 60-124646, Japanese Patent Application No. Hei 4-2).
No. 14199), but further improvement has been desired.

On the other hand, a phenolic resin molding material filled with glass fiber has excellent dimensional stability,
Or, if left for a long time while immersed in water or oil, there is a dimensional change, so there is a limit to its application to a part that requires precise dimensional accuracy comparable to metal.

[0005]

According to the present invention, a phenolic resin molding material highly filled with glass fibers has excellent abrasion characteristics without impairing the excellent mechanical strength, and has little swelling due to moisture absorption and oil absorption. A phenolic resin molding material having excellent dimensional stability can be easily obtained. Further, the obtained phenol resin molding material can be suitably used for mechanical parts such as resin pulleys and gears.

[0006]

SUMMARY OF THE INVENTION The present invention provides a glass fiber,
The organic natural material, the fine particle silica and the lubricating thermoplastic resin are contained in an amount of 60 to 70% by weight based on the total amount of the molding material.
Each component of the species is 7
A phenolic resin molding material characterized by being blended so as to be 5 to 93/1 to 5/5 to 15/1 to 5% by weight. 20 to 35 parts by weight, of which the xylene-modified novolak resin of the phenolic resin is compounded in an amount of 5 to 20 parts by weight based on the whole molding material, and further, as the fine particle silica, a secondary aggregated particle diameter of 20 μm
The present invention relates to a phenol resin molding material characterized by using the following synthetic amorphous silica.

Next, the phenol resin will be described. The xylene-modified phenolic resin used in the present invention has less water-soluble and moisture-resistant properties because it has less hydrophilic phenolic hydroxyl groups than the phenolic resin obtained by the reaction of ordinary formalin and phenolic monomer, but on the other hand However, they are inferior in curability to ordinary phenolic resins and are therefore unsuitable for use alone. Thus, in the present invention, by using a xylene-modified novolak resin and a normal phenol resin in combination, sufficient curability for use as a composition for a molding material is obtained without impairing the dimensional stability of heat and humidity.

In the present invention, the compounding amount of the phenolic resin component is 20 to 35 parts by weight based on 100 parts by weight of the whole molding material, and it is desirable to mix the phenolic resin component in a slightly smaller amount than a general molding material. If the amount is less than 20 parts by weight, it may be difficult to form a molding material, and if it exceeds 35 parts by weight, the dimensional change tends to increase. The amount of the xylene-modified novolak resin is preferably 5 to 15 parts by weight. If the amount is less than 5 parts by weight, the effect of improving the dimensional stability is small, and if it exceeds 15 parts by weight, the curability decreases. For the same reason, the xylene-modified novolak resin preferably has a xylene modification ratio of 20 to 80 parts by weight.

As the other phenol resin component, 5 to 20 parts by weight of a normal novolak resin is used. If the amount is less than 5 parts by weight, the improvement in curability is small, and if it exceeds 20 parts by weight, the moisture resistance decreases. In the present invention, although not particularly limited, a resol resin may be used in an amount of 10 parts by weight or less for imparting dimensional stability. This is because if more than 10 parts by weight is added, the curability is reduced.

To cure the phenolic resin, hexamethylenetetramine is usually used as a curing agent. The amount of hexamethylenetetramine is a commonly used amount and is 15 to 20% by weight based on the novolak resin.

Next, the filler will be described. In the present invention, as a filler, four kinds of glass fiber, organic natural material, fine particle silica and lubricating thermoplastic resin are used as essential components. The glass fiber is not particularly limited as long as it is a chopped strand that is usually used for a molding material.
Fiber lengths of ６6 mm are preferred. The blending amount of the glass fiber is 75 to 93% by weight in the above four components. If the amount is more than this range, the abrasion resistance decreases, and if the amount is less than this, the mechanical properties may be insufficient if the strength is high.

As the organic natural material, various types such as defibrated pulp, raw cotton pulp, powdered pulp, crushed cloth, wood powder, fir powder, and plywood powder can be used. Fibrous materials such as defibrated pulp, raw cotton pulp, powder pulp, and crushed cloth are preferred depending on the degree of dispersion, the bulk of the molding material, and the like, and particularly preferred are fine fibers having a fiber length of 1 mm or less. The amount of the organic natural material is preferably 5% by weight or less based on the whole filler so as not to impair the dimensional stability. If it is less than 1% by weight, the compounding effect is insufficient.
In the present invention, fine particle silica which is effective in improving abrasion resistance when used in combination with an organic natural material is used. The fine particle silica preferably has a particle diameter of 20 μm or less, and more preferably a synthetic amorphous silica having a secondary aggregated particle diameter of 20 μm or less. When the secondary aggregated particle diameter is 20 μm or more, the uniform dispersibility in the molding material is reduced, and the abrasion of a mold, a cylinder, and the like during molding is increased. The term “synthetic amorphous silica” as used herein refers to a structure in which single particles having a particle diameter of 50 nm or less are secondary aggregated in a bunch of grapes. Is what it is.
The amount is preferably 15% by weight or less based on the whole filler. If it is less than 5% by weight, the compounding effect is not sufficiently exhibited.

Further, a small amount of a lubricating thermoplastic resin having a function of forming a film on the surface of the molded article and reducing the wear coefficient is used. Specific examples thereof include polyolefins such as polyethylene, and fluororesins such as tetrafluoroethylene resin. In any case, the melting point, molecular weight, and the like are not particularly limited, but those having properties such that compatibility with the phenol resin, dispersibility, and workability during materialization are not impaired are effectively used. For example, polyethylene resin has a melting point of 120.
C. or less, particle size of 50 .mu.m or less, and the melting point of the tetrafluoroethylene resin is 400.degree. C. or less, and the particle size is 50 .mu.m or less. The blending amount is desirably 5% by weight or less based on the above-mentioned four components. If the amount is more than 5%, slippage is excessive, making it difficult to form a molding material and increasing the material cost. If the amount is less than 1% by weight, the effect of the compounding is not sufficiently exhibited.

The phenolic resin molding material of the present invention may optionally contain a filler other than those described above, and may further contain a curing aid, a release agent, a pigment and the like. In order to produce a molding material, these components are kneaded with a hot roll or the like, and then pulverized.

[0015]

Embodiments of the present invention will be described below. Table 1 shows the compositions of Examples and Comparative Examples, and Table 2 shows the properties obtained.

[0016]

[Table 1]

[0017]

[Table 2]

<< Measurement Method >> Sliding wear: Measured using a Suzuki abrasion tester. (Load: 2 kgf / cm ² , Sliding speed: 1000 mm / sec, Test time: 1 hour)-The amount of tapping wear was measured using a tapping wear measuring device manufactured by Sumitomo Bakelite. (Contact area 16mm ² , load 12.5k
(gf / cm ² , number of taps: 150,000 times) ・ Dimensional change was measured by measuring the rate of dimensional change in the radial direction of a 50 mm × 3 mm molded product. -Other characteristics were measured according to JIS K6911. As is clear from the results in Table 2, any of the examples can improve the wear characteristics and the dimensional stability without lowering the strength and the heat resistance, and can be retained. Comparative Example 1 is an example using only glass fiber as the inorganic filler. It is superior in strength to the example, but is inferior in wear characteristics. Comparative Example 2 is an example in which pulverized cloth was blended in a large amount. While the wear characteristics are good, all of the strength, heat resistance and dimensional stability are remarkably reduced. Comparative Example 3 is an example using only a normal phenol resin, but is inferior in dimensional stability.

[0019]

As is clear from the examples and comparative examples,
The phenolic resin molding material of the present invention is not only characterized by high strength and heat resistance, which are the characteristics of the glass fiber-filled phenolic resin molding material, but also by the combined use of organic natural materials and fine particle silica and the blending of a lubricating thermoplastic resin. It has excellent wear characteristics, and has an oil absorption and
It has the advantage of small dimensional change due to water absorption. Because of having such characteristics, the phenolic resin molding material of the present invention is suitably used for mechanical parts such as resin pulleys and gears.

Claims (3)

[Claims] 1. The glass fiber, the organic natural material, the finely divided silica and the lubricating thermoplastic resin are used in an amount of 60 to 100% based on the total amount of the molding material.
70% by weight, and each of the four components is 75 to 93/1 to 5/5 to 1 with respect to the total amount of these four components.
A phenolic resin molding material characterized by being blended so as to be 5/1 to 5% by weight. 2. A phenol resin is blended in an amount of 20 to 35 parts by weight based on the whole molding material, and a xylene-modified novolak resin of the phenol resin is incorporated in an amount of 5 to 15 parts by weight based on the entire molding material. 2. The phenolic resin molding material according to 1. 3. A secondary aggregated particle diameter of 2 as fine particle silica
3. A synthetic amorphous silica having a particle size of 0 [mu] m or less.
The phenolic resin molding material according to the above.