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:
Apr. 15, 1997
Filed:
Oct. 18, 1994
Hisashi Nakajima, Nagano-ken, JP;
Hideaki Koda, Ueda, JP;
Abstract
A method enabling stretch blow molding in a temperature range preferable for polyethylene and capable of releasing at a surface temperature suited to both releasing of a preform and subsequent stretch blow molding, by disconnecting the core die and the preform in advance by the use of pressure of gas. The injection molding of a predetermined preform involves filling an injection mold with molten polyethylene, releasing the preform from the cavity die and core die of the injection mold while a mouth portion of the preform is held by the lip die, and transferring the preform into a blow die to stretch blow mold into a hollow molded thin wall product. Gas forcibly enters into the boundary of the core die and the preform, before releasing the preform from the injection mold to isolate the inside wall of the preform from the core die. Releasing is effected while the inside of the preform is not completely cooled and is still at high temperature, and in a temperature range in which the surface temperature of the preform right after releasing is 80 to 90 deg. C. The step of stretch blow molding is performed within the time interval before the surface temperature of the preform which is elevated by the internal heat of the preform reaches 120 deg. C.