JP2001200138A - High-strength glass fiber-filled phenol resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass fiber-containing phenol resin molding material excellent in mechanical strengths at normal temperature and in heating and deterioration of heat resistance and suitable as a material alternate to metal in automobiles and electric and electronic fields. SOLUTION: This phenol resin molding material containing glass fiber comprises (a) 20-40 wt.% high-molecular weight novolak type phenol resin in which the weight average molecular weight when polystyrene is used as a standard substance is >=50,000, (b) 10-40 wt.% phenol resin in which the weight average molecular weight when polystyrene is used as a standard substance is <50,000, (c) 3-18 wt.% hexamethylenetetramine as a curing agent and (d) 40-60 wt.% glass fiber as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention provides a phenolic resin molding material containing glass fiber which has excellent mechanical strength such as tensile strength, impact strength and bending strength, and further has excellent mechanical strength when heated. It is.

[0002]

2. Description of the Related Art Phenolic resin molding materials containing glass fibers are excellent in heat resistance, dimensional stability, moldability, and the like, and have a long track record of being used in key industrial fields such as automobiles, electrics, and electronics. In particular, in recent years, by replacing those used for metal parts with phenolic resin molded products reinforced with glass fiber, it is possible to significantly reduce costs. Therefore, aggressive alternatives are being considered.
In order to promote further metal substitution, it is necessary to improve the properties of phenolic resin molding materials containing glass fibers.In particular, in the field of core parts such as automobile parts, not only strength at room temperature but also heat It has become necessary to improve the strength of steel and to suppress deterioration due to heat.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a phenol having excellent mechanical strength at normal temperature and heat and excellent heat deterioration as compared with the conventional high-strength phenol resin molding material reinforced with glass fiber as described above. It supplies resin molding material.

[0004]

According to the present invention, (a) a high molecular weight novolak type phenol resin having a weight average molecular weight of 50,000 or more when polystyrene is used as a reference substance is 20 to 40 with respect to the whole molding material. % By weight, and (b) a weight average molecular weight of 5 based on polystyrene as a reference substance.
10 to 40% by weight of a phenolic resin of less than 000,
(C) Hexamethylenetetramine 3 to 18 as a curing agent
It is a phenol resin molding material characterized by containing 40 to 60% by weight of glass fiber and (d) glass fiber as essential components.

The high molecular weight novolak type phenol resin (a) used in the present invention is a polycondensate of a trifunctional phenol and formaldehyde, and has a weight average molecular weight of 50,000 or more when polystyrene is used as a reference substance.
In order to make the molding material quick-curing, it is preferable that the methylene bond at the ortho-ortho position relative to the phenolic hydroxyl group is 60% or more of all methylene bonds. Furthermore, from the viewpoint of workability in forming a molding material, 50,000 to 20
Those having a molecular weight of not more than 000 are preferred.

On the other hand, the phenolic resin (b) having a weight-average molecular weight of less than 50,000 based on polystyrene used in the present invention can be either a novolak resin or a resol resin. Those having a workability of 1,500 to 30,000 are preferred.

In the present invention, a high molecular weight novolak type phenol resin (a) having a weight average molecular weight of 50,000 or more based on polystyrene as a reference material,
Although the phenolic resin (b) having a molecular weight of less than 000 is used, the phenolic resin having such a different molecular weight is used in combination, so that the viscosity of the molding material at the time of melting is not extremely increased, which is a characteristic of the high molecular weight phenolic resin. Heat resistance can be improved.

The mixing amounts of both phenol resins are (a) 20 to 40% by weight of a high molecular weight novolak type phenol resin and (b) a weight average molecular weight of 50,
It is 10 to 40% by weight of a phenol resin having a molecular weight of less than 000.
When the amount of the high molecular weight novolak phenolic resin is less than 20% by weight or the amount of the phenolic resin having a weight average molecular weight of less than 50,000 exceeds 40% by weight, the effect of heat resistance is reduced, and the amount of the high molecular weight novolak phenolic resin exceeds 40% by weight. In the case where the phenolic resin having a weight average molecular weight of less than 50,000 is less than 10% by weight, the viscosity of the molding material at the time of melting is increased, and the moldability is reduced.

In the present invention, hexamethylenetetramine (c) is used as a curing agent in an amount of 3 to 1 with respect to the whole molding material.
Use 8% by weight. If the amount is less than 3% by weight, the curing will be insufficient, and if the amount exceeds 18% by weight, the curability will not be further improved, and conversely, decomposition gas or the like tends to cause molding failure.

As for the glass fiber (d) used in the present invention, a glass fiber having a fiber diameter of 10 to 15 μm and a fiber length of 1 to 3 mm is required to be workable at the stage of forming a molding material and to obtain an obtained molded product. The strength is relatively good, and the compounding amount is preferably 40 to 60% by weight based on the whole molding material. 40
If the amount is less than 60% by weight, satisfactory strength is hardly obtained, and the dimensional change becomes large. If the amount exceeds 60% by weight, workability at the stage of forming a molding material is difficult, which may lead to a decrease in strength.

When the phenolic resin molding material of the present invention is obtained, the above-mentioned raw materials are uniformly mixed and then kneaded with a kneading machine such as a roll, a co-kneader, a twin-screw extruder alone or a combination of a roll and another mixer. Obtained by grinding. The phenolic resin molding material of the present invention has high mechanical strength and mechanical strength when heated, and can be used as a substitute for metal parts such as automobiles, electricity, and electronics.

Hereinafter, the present invention will be described with reference to examples. The test piece for characteristic evaluation was prepared by transfer molding, and the evaluation method was based on JIS K 6911. Table 2 shows the results.

Example 1 22.0 kg of phenol was placed in a 50 L high-pressure reactor having a heat exchanger, a heating device and a two-stage turbine type stirring blade of the same diameter, heated to 180 ° C., and heated to 0 ° C. with nitrogen gas. .8
After pressurizing to MPa, the formic acid content was previously reduced to 50 PP by ion exchange resin treatment with a diaphragm type high pressure metering pump.
13.3 Kg of 40% formalin reduced to M was added sequentially from the lower part of the reactor over 60 minutes to cause an addition condensation reaction. The temperature and the addition rate of the jacket of the reactor were adjusted so that the reaction temperature during this time was 180 to 200 ° C.
After completion of the addition, the temperature was maintained for 5 minutes, and after confirming that self-heating did not occur, a dehydration reaction was performed while returning to normal pressure over 30 minutes via a heat exchanger while heating to further maintain the temperature at 220 to 230 ° C. Was. Thereafter, the pressure was reduced to 1.3 KPa, and the unreacted phenol was removed for 30 minutes. The unreacted phenol was removed and taken out on a cooling vat, and the weight average molecular weight was reduced to polystyrene.
52,000 novolak phenolic resin 20.0K
g was obtained.

The novolak type phenol resin having a weight average molecular weight of 52,000 and the novolak type phenol resin having a weight average molecular weight of 8,000 in terms of polystyrene, glass fiber, hexamethylenetetramine, a curing aid, a lubricant,
A coloring agent and the like were mixed at a weight ratio shown in Table 1 and melt-kneaded with a biaxial roll to form a molding material. The obtained molding materials were evaluated for mechanical strength at 25, 100, 150 and 200 ° C. At 200 ° C., 250, 5
The mechanical strength of the samples treated for 00 and 1000 hours was evaluated. Table 2 shows the results.

Example 2 20.0 kg of phenol was placed in a reactor, 8.9 kg of 88% paraformaldehyde was used as an aldehyde, and this paraformaldehyde was previously mixed with 8.0 kg of phenol to form a suspension. Except that the liquid was supplied from the lower part of the reactor with a plunger-type high-pressure metering pump, unreacted phenol was not removed under reduced pressure, and the reaction temperature was 200 to 220 ° C. The reaction was carried out in the same manner as in Example 1 to obtain 27.0 kg of a novolak phenol resin having a weight average molecular weight of 102,000 in terms of polystyrene.

The novolak type phenol resin having a weight average molecular weight of 102,000, the novolak type phenol resin having a weight average molecular weight of 8,000 in terms of polystyrene, glass fiber, hexamethylenetetramine, a curing aid, a lubricant, a coloring agent, and the like are shown. Mix at the weight ratio shown in the ratio of 1,
The mixture was melted and kneaded with a biaxial roll to form a molding material. The obtained molding materials were evaluated for mechanical strength at 25, 100, 150 and 200 ° C. At 200 ° C., 25
The mechanical strength of the samples treated for 0, 500, and 1000 hours was evaluated. Table 2 shows the results.

Comparative Example 1 A novolak-type phenol resin having a weight-average molecular weight of 8,000 in terms of polystyrene, glass fiber, hexamethylenetetramine, a curing aid, a lubricant, a colorant, and the like were mixed in a weight ratio shown in Table 1. Then, the mixture was melt-kneaded with a biaxial roll to form a molding material. 25, 1
The mechanical strength at 00, 150 and 200 ° C. was evaluated. In addition, the mechanical strength of those treated at 200 ° C. for 250, 500, and 1000 hours was evaluated. Table 2 shows the results.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

As is apparent from the above Examples and Comparative Examples, the phenolic resin molding material of the present invention is excellent in mechanical strength such as tensile strength, impact strength and bending strength, and furthermore when heated. Excellent mechanical strength. Further, it is excellent in heat deterioration. Therefore, it greatly promotes metal substitution in the fields of automobiles, electricity, and electronics, and can be applied to other various molded article fields requiring heat resistance.

Claims (2)

[Claims] 1. The weight average molecular weight of (a) polystyrene as a reference substance is 50,0 based on the whole molding material.
High molecular weight novolak type phenolic resin 2 having a molecular weight of 00 or more
0 to 40% by weight, (b) 10 to 40% by weight of a phenol resin having a weight average molecular weight of less than 50,000 based on polystyrene as a reference material, (c) 3 to 18% by weight of hexamethylenetetramine as a curing agent, and (D) A phenolic resin molding material containing glass fiber, which contains 40 to 60% by weight of glass fiber. 2. The weight average molecular weight of (a) polystyrene as a reference substance is 50,0 based on the whole molding material.
High molecular weight novolak type phenolic resin 2 having a molecular weight of 00 or more
0 to 45% by weight, (b) 5 to 40% by weight of a phenol resin having a weight average molecular weight of less than 50,000 based on polystyrene, (c) 3 to 12% by weight of hexamethylenetetramine as a curing agent, and (D) An organic filler and / or an inorganic filler is contained in an amount of 30 to 60% by weight.
The phenolic resin molding material according to the above.