Expanded fluorine type resin products and a preparation process thereof
US5814409A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1997 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Sep 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/3154
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention relates to an expanded product comprising a thermoplastic fluroine type resin which does not have a cross-linking structure and has an expansion ratio of between 4-fold and 30-fold and a closed cell percentage of 40% or more. The expanded product contains at least one interface comprising layers having different cell densities and has a distribution index (Sc) and a coefficient of variation (Cv) of the maximum diameter of an open cell present at an optional cross section of each layer of 0<Sc.ltoreq.6 and 0<Cv.ltoreq.1, respectively, which are represented by the following equations: EQU Sc=(L.sub.Max. -L.sub.Min.)/Lav. (1) EQU Cv=SD/L.sub.av. (2) wherein L.sub.Max., L.sub.Min. and L.sub.av. represent maximum, minimum and average values of maximum diameters of open cells, respectively; and SD represents a standard deviation. The expanded product can be used as a polishing cloth for electronic materials and causes no dullness of edges, exhibits stable polishing performance for a long time, and has excellent mechanical strength such as tear strength and compressive strength, constant dielectric constant before and after compression of the expanded product, and an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.