Polyvinylacetal resin and process for producing the same
US7385005B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 7, 2003 |
| Grant date | Jun 10, 2008 |
| Priority date | — |
| Expiry date | Jul 1, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F16/38
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A polyvinylacetal resin powder with a low metal content, being excellent in transparency, moisture resistance and electrical insulating properties and having a large specific surface area, and a process for its production, are presented. A polyvinylacetal resin powder obtained by reacting polyvinyl alcohol and an aldehyde in the presence of an acid catalyst, which has an acetalization degree of at least 60 mol %, a specific surface area of from 1.50 to 3.50 m2/g, a bulk density of from 0.12 to 0.19 g/cm3, an average particle diameter of from 0.5 to 2, 5 μm and a metal content of at most 80 ppm.It is produced, for example, by feeding a reaction fluid containing polyvinyl alcohol, an aldehyde and an acid catalyst into a first reactor, to carry out an acetalization reaction, discharging the reaction fluid wherein the acetalization degree has reached from 10 to 60 mol %, and feeding the same into a second reactor to carry out a further reaction to bring the acetalization degree of polyvinylacetal to at least 65 mol %.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.