JPH0790248A - Abrasive material - Google Patents

Abstract

PURPOSE:To provide an abrasive material good in abrasive power, also excellent in the surface roughness of the molded product abraded therewith, thus suitable for after-treatment such as for removing burrs of molded products. CONSTITUTION:The abrasive material can be obtained by grinding a cured product obtained by hot pressing of a thermosetting resin composition prepared by homogeneously mixing and dispersing (A) 50wt.% of a phenolic resin, (B) 30wt.% of an organic filler and (C) 20wt.% of an inorganic filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasive suitable for removing burrs generated during molding of electronic parts, plastic products and the like.

[0002]

2. Description of the Related Art Conventionally, hard materials such as alumina, silicon carbide, and glass, and soft materials such as nylon, polycarbonate, and walnut shell powder have been mainly used as abrasives for post-treatment such as deburring of molded products. Has been done. In addition to these, recently, an abrasive of a thermosetting resin cured product having intermediate characteristics between the hard material and the soft material has been developed. This thermosetting resin cured material has a hardness that conventional materials do not have, and has come to be used considerably. However, the applications of molded products have been diversified year by year, and the characteristics required for abrasives have become strict and diversified. Especially for molded products related to electric parts, required characteristics such as dimensional accuracy are strict, and various measures are being taken to meet them.

[0003]

From the above viewpoints, the present inventor examined various abrasives for post-treating molded articles, and completed an abrasive having appropriate hardness, abrasivity and durability. It is a thing.

[0004]

According to the present invention, a thermosetting resin composition in which 40 to 70% of a phenol resin, 20 to 40% of an organic filler and 10 to 30% of an inorganic filler are uniformly mixed and dispersed is heated. The present invention relates to an abrasive that is pressure-hardened and then crushed the hardened material to have a predetermined particle size, and has appropriate hardness, abrasivity and durability. Abrasives have traditionally been used for deburring metal products, plastic products, etc.
Inorganic abrasives, organic abrasives, metal abrasives, etc. have been used for surface treatment and the like, depending on the quality of the object and the purpose of polishing. Recently, the materials to be polished have diversified,
Some shapes are complicated, and some have not been compatible with existing abrasives. The abrasive of the present invention has good polishing power and also has appropriate flexibility, so that it does not damage the object and has excellent durability.

The phenolic resin, which is the main component of the abrasive of the present invention, has the highest rigidity among the resins, and because it has a good binding force with the reinforcing material and the filler, it has a grinding wheel, a friction material, a refractory material, It is used as a binder for shell mode and the like. However, the phenol resin is a condensation-type thermosetting resin, and a single cured product has too much cohesive force and lacks flexibility. The present inventor has found that a compound containing 20 to 40% of an organic filler and 10 to 30% of an inorganic filler as a blend of a phenol resin composition is excellent in rigidity and flexibility and has good polishing property and durability. Found. That is,
By containing an organic filler, flexibility can be improved, and by containing an inorganic filler, rigidity can be further enhanced. As the content ratio, as described above, those containing 20 to 40% of the organic filler and 10 to 30% of the inorganic filler in the entire composition are particularly effective. If the organic filler is 20% or less, the flexibility is insufficient, and if it exceeds 40%, the rigidity is lowered. Further, if the content of the inorganic filler is 10% or less, the denseness of the composition is insufficient, and if it is 30% or more, the flexibility is insufficient.

[0006]

EXAMPLE A thermosetting resin composition containing 50% phenolic resin, 30% cellulosic filler as an organic filler, and 20% clay mineral filler as an inorganic filler has a pressure of 350 kg / cm ² and a temperature of 170. The cured product obtained by heating and pressing at ℃ was crushed to produce an abrasive having a particle size of 200 to 400 μm. Its properties were true specific gravity of 1.4 and hardness (Rockwell M scale) 110. This abrasive was used to remove burrs from phenolic resin molded articles for electrical parts. For comparison, deburring was performed using a cured melamine resin and glass beads as an abrasive. Table 1 shows the measurement results of the polishing characteristics (polishing power, surface roughness of the molded product).

Table 1 Abrasives Abrasive power Surface roughness Abrasives of Examples ○ ○ Melamine resin cured product × △ Glass beads ○ × (Evaluation ○: good, △: somewhat bad, ×: bad)

[0008]

As is clear from the above examples, the abrasive of the present invention has a good polishing power and an excellent surface roughness of the abraded molded product. It is suitable for post-treatment.

Claims (1)

[Claims] 1. A cured product obtained by heating and pressing a thermosetting resin composition in which 40 to 70% of a phenol resin, 20 to 40% of an organic filler and 10 to 30% of an inorganic filler are uniformly mixed and dispersed. An abrasive material characterized by being crushed.