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.

Date of Patent:
May. 21, 1991

Filed:

Mar. 22, 1990
Applicant:
Inventors:

Hitoshi Shiiki, Ibaraki, JP;

Minoru Tada, Kamisu, JP;

Kyoichi Nakamura, Kamisu, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08J / ; C08J / ;
U.S. Cl.
CPC ...
521 58 ; 264D / ; 264D / ; 264D / ; 521 56 ; 521 60 ; 521143 ;
Abstract

The present invention provides polypropylene resin pre-expanded beads formed by shrinking polypropylene resin pre-expanded beads originally having a bulk density of not higher than 0.0930 g/cc to give them a bulk volume ratio of 10-75% at normal temperature and normal pressure, a manufacturing method thereof and an expansion-molding method with the aforementioned pre-expanded beads. According to this invention, it is possible to greatly reduce storing and transporting costs per unit weight of pre-expanded beads.


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