The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 02, 1992
Filed:
Dec. 26, 1989
Kanegafuchi Kagaku Kogyo Kabushiki Kaisha, Osaki, JP;
Abstract
An improved process for preparing pre-expanded particles of a polyolefin resin, wherein polyolefin resin particles are dispersed in water in a pressure vessel, the particles are impregnated with a volatile blowing agent which is butane containing not less than 70 percent by weight of isobutane, the temperature of the mixture of particles in water is elevated to a temperature close to the melting point of the particles under a pressure equal to or higher than the vapor pressure of the blowing agent, and the mixture is released into a low pressure zone. The obtained pre-expanded particles are not fused together or adhered to each other, and are not shrunken. Environmental damage, such as destruction of the ozone layer, is avoided since fluorochlorocarbon is not used as a blowing agent.