| 摘要 |
PURPOSE:To collect screened-through particles in good performance by mixing powder of hardened polyester resin below a particle size of 150mum with unsaturated polyester resin in liquid state in a specified proportion followed by hardening, by post-hardening in specified temperature condition and then crushing. CONSTITUTION:100 parts by weight by weight of powder of hardened polyester resin having a particle size below 150mum is mixed with 300 parts by weight or more of polyester resin liquid state followed by agitation until uniform consis tency is obtained. After hardening with a hardening agent added, the admixture is hardened for 4-10 hr, or preferably 4-7hr, at a temperature of 100-180 deg.C, or desiarably 100-150 deg.C. As this hardened polyester resin is in lumps, they are coarse crushed with a jaw crusher etc. followed by further crushing with a roll mill etc., and then screening is carried out to provide an abrasive material with specified particle size. Thus screened-through particles below a particle size of 150mum can be collected without impairing the quality as a grinding element such as hardness and form as well as without lowering the rate of collection.
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