JPH107887A - Melamine-phenol resin-molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a melamine-phenol resin-molding material which is excellent in an arc-resistant property and a tracking resistant property and possesses a small dimensional variation rate. SOLUTION: This molding material is prepared by blending 100 pts.wt. of a melamine resin having a number-average molecular weight of 180-400 with 10-30 pts.wt. of a phenol resin having a number-average molecular weight of more than 10,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melamine phenol resin molding material having excellent arc resistance and tracking resistance and having a small dimensional change.

[0002]

2. Description of the Related Art Melamine resin molding materials have been used for wiring equipment and electric appliances due to their excellent tracking resistance, electrical insulation properties, coloring properties, etc., but are used with recent miniaturization of products. High dimensional accuracy is also required for parts. For this reason, a resol type solid or liquid phenol resin mainly containing a methylol group having a number average molecular weight of about several hundreds has been conventionally added to a melamine resin to such an extent that arc resistance and tracking resistance are not impaired. Attempts have also been made to blend a dimethylene ether type resole resin having a number average molecular weight of 180 to 400 as a material having more excellent dimensional accuracy, and an effect has been obtained (Japanese Patent Application Laid-Open No. HEI 0-1990).
3-74457). These materials have a smaller dimensional change rate than a molding material containing only melamine resin, but at present, a sufficient dimensional change rate is not obtained as compared with a phenol resin molding material. Therefore, it is not used for small molded products requiring high dimensional accuracy. Therefore, the melamine resin molding material does not require a high degree of dimensional accuracy, and is used only in applications where coloring of electric parts, foods and the like, which require arc resistance and tracking resistance, is absolutely necessary.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a melamine phenol resin molding material which has excellent arc resistance and tracking resistance and has a small dimensional change.

[0004]

According to the present invention, a number average molecular weight of 1 is provided.
A melamine / phenol resin molding material characterized in that 10 to 30 parts by weight of a phenol resin having a number average molecular weight of 10,000 or more is mixed with 100 parts by weight of a melamine resin of 80 to 400. The phenolic resin used in the present invention melts and self-curs upon heating.
Phenol resin of 000 or more, for example, Bell Pearl, S-890 manufactured by Kanebo Co., Ltd. is preferable.

[0005] Among melamine resins and phenol resins accompanied by a condensation reaction, the phenol resin has three functional groups, which is less than six of the melamine resins. Therefore, by adding a phenol resin to the melamine resin, the molding shrinkage at the time of crosslinking is smaller than that of the melamine resin itself. Number average molecular weight 10
A phenolic resin having a molecular weight of 000 or more has fewer crosslinking points as compared with a phenolic resin having a number average molecular weight of several hundreds. Therefore, it is considered that the shrinkage effect at the time of crosslinking becomes smaller. The compounding amount of the phenol resin is preferably 10 to 30 parts by weight based on 100 parts by weight of the melamine resin. When the amount is less than 10 parts by weight, the effect of suppressing the dimensional change rate is not recognized, and when the amount is more than 30 parts by weight, workability during production is inferior and materialization is difficult.

Melamine resins for producing molding materials,
Raw materials used with the phenolic resin are fillers, hardeners, colorants, release agents, and the like. The melamine resin used in the present invention may be modified with an epoxy resin, rubber or the like. Further, a part of the melamine resin may be replaced with a urea resin or the like. In the method for producing a molding material using the melamine-phenol resin composition, kneading may be carried out with a usual mixing roll or twin-screw extruder, or granulation may be carried out with a high-speed rotary mixer.

The molding method for obtaining a molded product using the molding material from the melamine-phenol resin composition according to the present invention can be applied to any of injection molding, transfer molding, compression molding and the like, and is not limited. .

[0008]

EXAMPLES The raw materials shown in Table 1 were kneaded in a predetermined mixture by a mixing roll and pulverized to produce a molding material. The bending strength, arc resistance, tracking resistance (IEC. Pub 112), molding shrinkage, and dimensional change (after 180 ° C./24 hr treatment) of the obtained molding material were measured. The molding of the test piece was performed by transfer molding, and the molding conditions were 150 ° C. for 3 minutes.

[0009]

[Table 1] * 1: Methylolation degree 1.70, number average molecular weight 300 * 2: 50 mol% of dimethylene ether group, 15% methylol group, number average molecular weight 750 * 3: Resol type phenol resin having a number average molecular weight of 10,000 or more As described above, when a resole resin having a number average molecular weight of 10,000 or more was used, a melamine phenol resin molding material excellent in arc resistance and tracking resistance and excellent in dimensional change was obtained.

[0010]

According to the present invention, it is possible to obtain a molded article having excellent arc resistance and tracking resistance and an excellent dimensional change. Therefore, it is excellent as arc resistance and tracking resistance which could not be conventionally produced, and can easily produce molded articles for applications requiring dimensional accuracy, and thus is suitable as an industrial melamine / phenol resin molding material. .

Claims (1)

[Claims] 1. A melamine / phenol resin molding material characterized in that 10 to 30 parts by weight of a phenol resin having a number average molecular weight of 10,000 or more is mixed with 100 parts by weight of a melamine resin having a number average molecular weight of 180 to 400.