Prefoamed propylene polymer-base particles, expansion-molded article produced from said particles and production process of said article
US4695593A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1986 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Feb 21, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/16
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Prefoamed polypropylene-base particles have a crystalline structure featuring a high-temperature peak appeared on the higher temperature side than the peak inherent to polypropylene-base resins on a DSC curve obtained by differential scanning calorimetry upon heating 1-3 mg of the prefoamed polypropylene-base particles at a constant heating rate of 10.degree. C./min. to 220.degree. C. by means of a differential scanning calorimeter and the internal pressure decreasing velocity coefficient k of the particles is either equal to or smaller than 0.70 (k.ltoreq.0.70) at 25.degree. C. and 1 atm. The prefoamed polypropylene-base particles can be formed into an expansion-molded polypropylene-base article by imparting foamability to the particles, filling the resultant particles in a mold and then heating the particles so as to cause their expansion. The expansion-molded article has good surface quality, excellent dimensional accuracy, and superb physical properties such as shrinkage factor, compression hardness, compression set and interparticle fusion-bonding property.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.