Expanded bead and method for producing the same
US12240956B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2022 |
| Grant date | Mar 4, 2025 |
| Priority date | — |
| Expiry date | Apr 25, 2042 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2423/16
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An expanded bead having a tubular shape with a through hole and a method for producing the same are provided. The expanded bead includes a foamed core layer and a covering layer. A polyolefin-based resin included in the covering layer has a melting point lower than a melting point of a polypropylene-based resin included in the foamed core layer. An average hole diameter d of the through hole of the expanded bead is less than 1 mm, and a ratio d/D of the average hole diameter d to an average outer diameter D of the expanded bead is 0.4 or less. The polypropylene-based resin for the foamed core layer has a flexural modulus of 1,200 MPa or more and a melting point of 158° C. or lower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.