JPH09169889A - Phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phenolic resin molding material which can give steady heat stability in injection molding without increasing the number of production steps even when a fine powder is cut by adding a specified additive when kneading a material. SOLUTION: This molding material contains 30-50wt.% phenolic resin, 40-60wt.% glass fibers and 0.1-0.5wt.% additive comprising a silicone oil. The silicone oil used preferably comprises an alkyl-modified silicone oil with a viscosity of about 10-50cSt. The phenolic resin used preferably comprises a novolak or resol phenolic resin alone or a mixture thereof. It is desirable to use a dimethyl ether type resol resin together with a methylol type resol resin for the resol phenolic resin. It is desirable to use glass fibers having a diameter of 10-15μm and a length of 1-3mm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention provides a phenolic resin molding material having excellent mechanical strength and injection moldability.

[0002]

2. Description of the Related Art The production method of phenol resin molding material is
The mainstream method is to heat and knead a mixture of a phenol resin and various base materials with a roll, form a sheet and cool the mixture, and pulverize and mix it into a material. However, in this production method, of course, fine powder is generated during pulverization and mixing, and recently, there is an increasing demand for cutting this fine powder from the viewpoint of workability at the customer's site. In addition, customers often produce products by injection molding from the viewpoint of production efficiency.For materials for injection molding, a release agent is post-added and the sliding effect is used to provide thermal stability. We provide the materials that But,
In the case of injection molding materials that require such fine powder cutting, if the method of finely cutting the material to which the release agent has been added afterwards is used, the release agent added at the time of cutting the fine powder will also fly. Therefore, it is difficult to stably secure the amount, and the thermal stability tends to vary. Further, in the case where the method of post-adding the release agent to the material obtained by cutting the fine powder is adopted, the number of production steps increases, and when the release agent is post-added and mixed, secondary fine powder is generated. However, the fact is that there are drawbacks.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a glass fiber-reinforced high-strength phenol resin molding material, which does not increase the number of production steps even if the material is finely powdered, and obtains stable thermal stability in injection molding. As a result of various studies to develop such a material, the mechanical strength was maintained by adding an alkyl-modified silicone oil when kneading the material.
The present inventors have completed the present invention by finding that stable thermal stability can be obtained in injection molding.

[0004]

The present invention contains 30 to 50% by weight of a phenol resin with respect to the entire molding material,
The present invention relates to a phenol resin molding material containing 40 to 60% by weight of glass fiber and 0.1 to 0.5% by weight of an alkyl-modified silicone oil as an additive.

The phenolic resin used in the present invention is not particularly limited, and a novolac type or a resol type may be used alone or in combination. When the novolac type phenol resin is used alone, the workability in the materializing stage, the moldability (particularly the injection molding), and the properties of the obtained molded product are relatively good. It is preferable to use one having a number average molecular weight of 800 to 1000 and an O / P ratio of 1 or less, and it is preferable to add hexamethylenetetramine as a curing agent in an amount of 15 to 20% by weight based on the novolac type phenol resin. Even when only the resol type phenol resin is used, for the same reason, the solid dimethylene ether resol resin having a number average molecular weight of 800 to 1200 and the number average molecular weight of 600 are used.
It is preferable to use a solid methylol type resole resin of up to 1000 in combination, and the mixing ratio (weight ratio) of these dimethylene ether type resole resin and the methylol type resole resin is preferably 3: 7 to 7: 3. For the same reason, when the resol-type phenol resin and the novolac-type phenol resin are used together, the number average molecular weight is 80.
It is preferable to use a dimethylene ether type resole resin of 0 to 1200 and a novolac type phenol resin having a number average molecular weight of 800 to 1000 at a compounding ratio (weight ratio) of 8: 2 to 6: 4.

For glass fibers, the fiber diameter is 10
The workability in the materializing stage and the strength of the obtained molded product are relatively good when a resin having a fiber length of ˜15 μm and a fiber length of 1 to 3 mm is used.
0-60% by weight is preferred. If it is 40% by weight or less, satisfactory strength cannot be obtained and dimensional change is large, and if it is 60% by weight or more, workability in the materializing stage is difficult and strength is lowered. It is preferably 40 to 60% by weight.

The effect of the alkyl-modified silicone oil added at the time of kneading the material in order to obtain stable thermal stability in injection molding, which is the object of the present invention, is not clearly confirmed, but the silicone oil bleeds on the surface of the material, It is speculated that thermal stability is imparted from the sliding effect. The addition amount is preferably 0.1 to 0.5% by weight based on the whole molding material. The reason for this is that if the amount is 0.1% by weight or less, the effect of improving the thermal stability is low, and if the amount is 0.5% by weight or more, the roll workability and strength are deteriorated. Regarding the viscosity of the alkyl-modified silicone oil, those having a viscosity of about 10 to 50 centistokes are good in terms of handling and dispersibility.

When the phenol resin molding material of the present invention is obtained, it is obtained by uniformly mixing the above raw materials, then heating and kneading with a roll kneader and pulverizing. The phenolic resin molding material of the present invention is excellent in mechanical strength and injection moldability,
It can be applied as a substitute for metal parts such as electronics.

[0009]

EXAMPLES Tables 1 to 3 show the formulations and characteristics of the examples and comparative examples.

[0010]

As is clear from the above examples and comparative examples, the phenol resin molding material of the present invention is excellent in mechanical strength, does not increase the number of production steps, and is stable in injection molding even if the material is finely cut. It was confirmed that the obtained thermal stability was obtained.

[0011]

[Table 1]

[0012]

[Table 2]

[0003]

[Table 3]

Claims (2)

[Claims] 1. A phenol resin is contained in an amount of 30 to 50% by weight, a glass fiber is included in an amount of 40 to 60% by weight, and a silicone oil as an additive is included in an amount of 0.1 to 0.5% by weight, based on the whole molding material. A phenol resin molding material characterized by: 2. The phenol resin molding material according to claim 1, wherein the silicone oil is an alkyl-modified silicone oil and has a viscosity of 10 to 50 centistokes.