Method of removing coating films
First Claim
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1. A method for removing a cured coating film of a thermosetting resin composition from surfaces of polyolefin resin substrates, comprising the steps of:
- treating crushed particulates of polyolefin resin substrates having a particle size in a range of from 0.5 to 20 mm, in an aqueous alkali solution having a concentration of 0.2 to 4.0% by weight at a temperature of 110°
C. or higher, but lower than a melting point of said substrates to obtain treated resin substrate particulates;
contacting the treated resin substrate particulates with each other, thereby removing said cured coating film from said particulates by shearing force in a screw feeder polishing machine or in a polishing machine equipped with a high-speed vessel stirrer; and
recycling resulting treated particulates which have had said cured coating film removed for reuse as polyolefin resin.
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Abstract
Improved methods of removing coating films from resin substrates includes first treating the resin substrates in an aqueous alkali solution with a concentration of 0.1 wt % or more at a temperature of 110° C. or more, which temperature is lower than the melting point of the substrates and then polishing the surfaces of the substrates by either bringing them into contact with each other in suitable equipment such as a screw feeder, or using an abrasive in suitable equipment such as a high-speed vessel type stirrer, or subjecting the substrates to a liquid honing process.
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Citations
10 Claims
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1. A method for removing a cured coating film of a thermosetting resin composition from surfaces of polyolefin resin substrates, comprising the steps of:
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treating crushed particulates of polyolefin resin substrates having a particle size in a range of from 0.5 to 20 mm, in an aqueous alkali solution having a concentration of 0.2 to 4.0% by weight at a temperature of 110°
C. or higher, but lower than a melting point of said substrates to obtain treated resin substrate particulates;contacting the treated resin substrate particulates with each other, thereby removing said cured coating film from said particulates by shearing force in a screw feeder polishing machine or in a polishing machine equipped with a high-speed vessel stirrer; and recycling resulting treated particulates which have had said cured coating film removed for reuse as polyolefin resin. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification