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:
Oct. 17, 1995
Filed:
Mar. 11, 1994
Hisao Tokoro, Tochigi, JP;
Kazuo Tsurugai, Utsunomiya, JP;
Hidehiro Sasaki, Utsunomiya, JP;
Masaharu Oikawa, Utsunomiya, JP;
JSP Corporation, Tokyo, JP;
Abstract
The present invention relates to uncrosslinked polyethylene particles for the production of expanded particles that can easily and securely produce expanded particles which can be molded without applying a special internal pressure, are excellent in moldability, such as secondary expansion, fusion and dimensional accuracy, and have a high expansion rate and to uncrosslinked polyethylene expanded particles made of said uncrosslinked polyethylene particles. The present uncrosslinked polyethylene particles for the production of expanded particles are resin particles whose base resin is an uncrosslinked polyethylene having a density of over 0.920 g/cm.sup.3 and up to and including 0.940 g/cm.sup.3 and wherein, in the DSC curve that is obtained by using a differential scanning calorimeter in such a manner that after 1 to 10 mg of the resin particles is heated to 200.degree. C. at 10.degree. C./min and then is cooled to room temperature at 10.degree. C./min, heating is again carried out to 200.degree. C. at 10.degree. C./min and during the second heating the measurement for the DSC curve is carried out, q.sub.1 /q.sub.total .gtoreq.0.5 wherein q.sub.1 stands for the quantity of heat absorbed in the range of the DSC curve of from 50.degree. C. to (the melting point-10) .degree. C. in terms of J/g and q.sub.total stands for the total quantity of absorbed heat of the DSC curve of from 50.degree. C. to the temperature at which the melting is completed in terms of J/g is satisfied, and the temperature width at 1/2 of the peak height h of the endothermic peak whose apex is at 115.degree. C. or higher is 5.degree. C. or more. Further, the present uncrosslinked polyethylene expanded particles are obtained by impregnating the above resin particles with an expanding agent, dispersing the resin particles in a dispersing agent in a closed vessel, and discharging the resin particles and the dispersing medium from the vessel at a temperature equal to or over the softening temperature of the resin particles into a low-pressure region.