JPS5924741A - Phenolic molding material - Google Patents

Abstract

PURPOSE:To provide a phenolic molding material which gives moldings having a high resonance frequency and a high extent of damping, by incorporating rubber and adjusting the specific gravity to a specified value. CONSTITUTION:5-30wt% rubbr is mixed with a phenolic molding material so as to give moldings having a specific gravity of 2 or above. When the amount of the rubber is less than 5wt%, the extent of damping is lowered, while when the amount exceeds 30%, the resonance frequency is reduced. As the filler to give moldings having a specific gravity of 2 or above, those having a large specific gravity, such as silica, alumina or barytes, are preferred. A filler having a large specific gravity and high hardness, such as silica, is particularly preferred. As additives other than the phenolic resin, rubber and the filler having a large specific gravity, conventional hardener, parting agent, colorant, filler, etc. can be used as such.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molding material for obtaining acoustic parts such as speaker boxes, turntables, player cabinets, baffle plates, etc., and its purpose is to produce molded products with a large resonance frequency and damping amount. The objective is to provide a molding material for obtaining.

Aluminum die-casting has traditionally been used for acoustic components, but it has the drawbacks of low damping and high cost.Also, when using wood or plywood, the resonant frequency is small and it is difficult to obtain a constant volume of sound. It had the disadvantage of requiring a large structure.

The present invention solves the above-mentioned drawbacks, and by using a molding material that contains 5 to 30% by weight (hereinafter simply referred to as %) of rubber and has a molded product specific gravity of 2 or more, the resonant frequency and damping amount are large. I was able to obtain the goods.

The present invention will be explained in detail below. The phenolic resin used in the present invention may be either a resol type or a novolak type, and
It also includes cresol resins and xylenol resins, and further includes phenolic resins modified with molasses, lignin, xylene, naphthalene, petroleum aromatic hydrocarbon resins, and the like. The rubber is not particularly limited as long as it is compatible with the phenol resin, such as nitrile rubber. The amount of rubber added must be 5 to 30%, and 5%
If it is less than 30%, the damping amount becomes small, and if it exceeds 30%, the resonance frequency becomes small. As a filler to make the specific gravity of the molded product 2 or more, it is preferable to add a filler with a high specific gravity such as silica, alumina, pallite, etc. In particular, a filler with a high specific gravity and high hardness such as silica is preferably added. It is desirable to add.

As additives other than phenolic resins, rubbers, and large specific gravity fillers, commonly used curing agents, mold release agents, colorants, reinforcing agents, fillers, etc. can be used as they are, and these resins, rubbers, and fillers A phenolic resin molding material is obtained by mixing, kneading, pulverizing, and granulating as required.

The present invention will be explained below based on Examples and Comparative Examples.

Examples 1 and 2 and Comparative Examples Phenolic resin molding materials were obtained by blending, mixing, kneading, and pulverizing a novolak type phenolic resin having a melting point of 90° C. according to the formulation table in Table 1.

Table 1 The phenolic resin molding materials of Examples 1 and 2 and Comparative Example were molded at a molding pressure of 100 kg/cm2 at 150°C for 6 minutes to obtain molded products, and conventional products such as wood plywood and aluminum die-cast were added for testing. As clearly shown in Table 2, the specific gravity, damping amount, and resonance frequency of the molded products obtained from the phenolic resin molding material of the present invention were large, confirming the superiority of the phenolic resin molding material of the present invention.

Table 2

Claims (1)

[Claims] (1) A phenolic resin molding material containing 5 to 30% by weight of rubber and having a molded product specific gravity of 2 or more.