JP2000063622A - Phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding material which can give a molding excellent in fatigue strength, impact strength, and abrasion resistance by mixing a novolac phenolic resin with hexamethylenetetramine, a finely ground glass fiber, and a ground cotton fabric. SOLUTION: It is desirable that the resin is a random novolac resin, a high- ortho novolac resin or the like, and if necessary, 30-60 wt.% of the whole molding material of a resol type phenolic resin can be incorporated. The mixing amount of hexamethylenetetramine is preferably 7-30 pts.wt. per 100 pts.wt. novolac phenolic resin. The finely ground glass fiber is desirably an unbound one having a fiber diameter of 5-15 μm and a fiber length of 30-500 μm and can reduces abrasiveness to, especially, a metal. The ground cotton fabric is added for the purpose of maintaining and improving the fatigue strength and impact strength of a molding and is desirably one having a fiber length of 0.2-3.0 mm. The combination of the finely ground glass fiber with the ground cotton fabric permits the molding material to give a molding having the features of both and showing counterbalanced defects of both. The material is suited for machine components of e.g. an automotive brake piston.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a phenol resin molding material having excellent fatigue strength, impact strength and abrasion resistance.

[0002]

2. Description of the Related Art Phenolic resin molding materials have an excellent balance of heat resistance, electrical characteristics, mechanical characteristics, dimensional stability and the like and are used in a wide range of fields including mechanical parts of automobiles. Mechanical components such as magnet switches and other movable parts, pulleys, automobile brake pistons, and brake boosters have fatigue strength because loads are repeatedly applied to the parts and impact strength because cracks easily occur due to contact with adjacent parts. In addition, the resin parts and the metal parts slide against each other, and wear resistance is required. For this reason, a phenol resin molding material containing a crushed cotton fabric having relatively high strength and excellent wear resistance has been used for such applications (for example, JP-A-4-103654). However, the fatigue strength and impact strength required for moving parts or mechanical parts in recent years are higher and more severe, and the fatigue strength is not sufficient with a conventional phenol resin molding material containing a crushed cotton fabric. When a phenol resin molding material containing glass fiber is used, the fatigue strength increases, but the wear resistance decreases, so it has not been put to practical use.

[0003]

The present invention has been made as a result of various studies in order to solve these problems, and its object is to provide excellent fatigue strength, impact strength and wear resistance. We also provide phenolic resin molding materials.

[0004]

The present invention comprises (a) a novolac type phenolic resin, (b) hexamethylenetetramine, (c) a finely pulverized product of glass fiber, and (d) a pulverized product of cotton fabric. The present invention relates to a characteristic phenol resin molding material, and provides a phenol resin molding material excellent in fatigue strength, impact strength and abrasion resistance.

The (a) novolac type phenol resin of the present invention may be any one used in ordinary phenol resin molding materials, and is not particularly limited to random novolac resin, high ortho novolac resin and the like. Further, a resol-type phenol resin can be blended if necessary. The compounding amount is usually 30 to 60 of the entire molding material.
% By weight. The (b) hexamethylenetetramine of the present invention is in the form of fine powder used as a curing agent for ordinary phenol resins, and is usually 7 to 30 parts by weight, preferably 12 to 100 parts by weight of novolac type phenol resin. It is used by blending up to 20 parts by weight.

The finely pulverized glass fiber (c) used in the present invention is a finely pulverized glass fiber which has been conventionally used, and usually has a fiber diameter of 15 μm or less and a fiber length of 500 μm.
In the following, the unconverged one is used. By using the finely pulverized glass fiber having such a shape, it is possible to reduce abrasion resistance, particularly abrasion to metal.
Ordinary glass fibers have excellent fatigue strength and impact strength, but poor wear resistance. On the other hand, the finely pulverized product of the glass fiber (c) has some deterioration in fatigue strength and impact strength, but still maintains a high level, and wear resistance is greatly improved.

Finely pulverized glass fiber has a fiber diameter of 5 to 15 μm.
m, fiber length 30 to 500 μm, and not converged. Those having a fiber diameter of less than 5 μm are difficult to manufacture and are not generally commercially available. If it exceeds 15 μm, the frictional resistance to the metal increases and the wear resistance decreases. Further, if the fiber length is less than 30 μm, the effect of improving fatigue strength is small, and if it exceeds 500 μm, the frictional resistance to metal increases and the wear resistance decreases. Further, in the finely pulverized glass fibers that have been converged, the fibers do not defibrate into the phenol resin molding material one by one and remain as a bundle of some fibers, so the bundle of fibers exposed on the surface of the molded product is considered to be metal. When they come into contact with each other, they are defibrated, and the defibrated fibers are separated from the molded article and enter the sliding portion, which promotes wear of the metal, which is not preferable. Further, the compounding amount is 5 to 5 of the whole molding material.
20% by weight is preferred. If it is less than 5% by weight, the fatigue strength and impact strength are not sufficiently improved, and if it exceeds 20% by weight, the wear resistance is lowered.

The (d) pulverized cotton fabric used in the present invention is
It is added to maintain and improve the fatigue strength and impact strength of the molded product. The crushed cotton fabric (d) is not particularly limited, but preferably has a fiber length of 0.2 to 3.0 mm. If it is less than 0.2 mm, the impact strength is not sufficiently improved, and if it exceeds 3.0 mm, the workability at the stage of forming a molding material is difficult and the apparent density is lowered. Further, the compounding amount is preferably 3 to 15% by weight of the whole molding material. If it is less than 3% by weight, the fatigue strength and impact strength are not sufficiently improved, and if it exceeds 15% by weight, the workability in the molding material stage is difficult and the apparent density is lowered.

The present invention has the characteristics of both components by adding (c) a finely pulverized product of glass fiber and (d) a pulverized product of cotton fabric to a novolac type phenolic resin, and complements the respective drawbacks. is there. Therefore, the fatigue strength and the impact strength are equal to or higher than those of ordinary glass fiber or the crushed product of cotton fabric, and the abrasion resistance is greatly improved. Further, the fatigue strength and impact strength are greatly improved as compared with those using the crushed cotton fabric. Further, the phenol resin molding material of the present invention further includes organic powder such as wood powder, pulp powder, phenol resin laminate, crushed product of molded product, talc, clay, mica, calcium carbonate, inorganic powder such as carbon. One or more of the above can be used. Glass fibers, which are long fibers, cannot be used even in a small amount because they deteriorate the abrasion resistance. Further, various additives such as a lubricant, a coloring agent, a curing accelerator, a flame retardant and the like can be appropriately blended. The phenol resin molding material of the present invention includes a resin component, a filler,
It can be manufactured by blending other additives, kneading with a roll mill, a twin-screw kneader or the like, and pulverizing.

[0010]

The present invention will be described with reference to the following examples. In the formulation, “part” is part by weight. The resin and the filler shown in Table 1 were mixed and kneaded with a heating roll to obtain a phenol resin molding material.

(Measurement method) Preparation of test molded article: transfer molding (175 ° C.,
3 minutes) 1. Fatigue strength: In the method of measuring bending strength according to JIS K 6911, a load was set to 6 Kgf, and this load was repeatedly applied to a test piece, and the number of times until breakage was shown. 2. Impact strength: The Charpy impact strength according to JIS K 6911 was shown. 3. Abrasion resistance: A Suzuki type abrasion tester was used to slide the test molded article and the metal (S-55C) to measure the amount of abrasion of the metal. (Load: 5 Kgf / cm ² , peripheral speed: 100 mm / sec,
Test time 1 hour)

Table 1 Example 1 Comparative example 1 Comparative example 2 Comparative example 3 Glass fiber * Fiber diameter (μm) 15 15 −15 Fiber length (μm) 100 1500 −100 Composition Phenolic resin 50 50 50 50 50 Hexamine 10 10 10 10 Glass fiber 10 10 − 10 Cotton pulverized product 5 5 5 − Wood flour 20 20 30 25 Other 5 5 5 5 Characteristics Fatigue strength (number of times) 5 × 10 ⁴ 8 × 10 ⁴ 8 × 10 ³ 7 × 10 ³ Impact strength (kJ / mm ) 3.8 3.8 2.8 2.8 Abrasion resistance (mg) 0.5 30 0.5 0.5 * In Example 1 and Comparative Example 3, unconverged glass fiber finely pulverized products were used. Comparative Example 1 used converged glass fibers.

[0013]

As is apparent from the above examples, since the phenol resin molding material of the present invention is excellent in fatigue strength, impact strength and wear resistance, it can be used in moving parts such as magnet switches, pulleys and automobiles. Suitable for mechanical parts such as brake pistons and brake boosters.

Claims (2)

[Claims] 1. (a) a novolac type phenolic resin,
A phenol resin molding material containing (b) hexamethylenetetramine, (c) a finely pulverized product of glass fibers, and (d) a pulverized product of a cotton fabric. 2. A finely pulverized glass fiber having a fiber diameter of 5 to 15
The phenol resin molding material according to claim 1, which has a fiber length of 30 μm and a fiber length of 30 to 500 μm and is not converged.