Title:
POLYVINYL ACETAL SHEET AND PROCESS FOR PRODUCTION THEREOF
Document Type and Number:
WIPO Patent Application WO/2008/050517
Kind Code:
A1
Abstract:
The invention provides a polyvinyl acetal sheet which is useful in producing
laminated glass and excellent in the adhesion to glass and which permits easy
control of adhesiveness and exhibits little discoloration, high transparency,
and excellent penetration resistance even under high-temperature conditions;
a process for production of the same; and a process for production of polyvinyl
acetal particles to be used in the sheet. The polyvinyl acetal sheet is characterized
by having a porosity of 60 to 85% and by being produced by molding polyvinyl acetal
particles having a degree of acetalization of 75.0 to 84.0% by mass into a film.
The polyvinyl acetal particles are preferably produced by a process of subjecting
100 parts by mass of polyvinyl alcohol and 40 to 75 parts by mass of an aldehyde to
acetalization in the presence of an acid catalyst at a reaction temperature of
20 to 60°C which process comprises feeding polyvinyl alcohol, an aldehyde
and an acid catalyst into a reactor to conduct acetalization, discharging the
reaction mixture from the reactor when the degree of acetalization has reached
at least 13% by mass, and aging the discharged reaction mixture.
Inventors:
TSUJI TSUYOSHI (JP)
KOHSAKA MASANOBU (JP)
YOSHII SHIGEHARU (JP)
SAITO TOMOO (JP)
MASHIKO YOSHIHIRO (JP)
KOHSAKA MASANOBU (JP)
YOSHII SHIGEHARU (JP)
SAITO TOMOO (JP)
MASHIKO YOSHIHIRO (JP)
Application Number:
PCT/JP2007/064817
Publication Date:
May 02, 2008
Filing Date:
July 27, 2007
Export Citation:
Assignee:
DENKI KAGAKU KOGYO KK (JP)
TSUJI TSUYOSHI (JP)
KOHSAKA MASANOBU (JP)
YOSHII SHIGEHARU (JP)
SAITO TOMOO (JP)
MASHIKO YOSHIHIRO (JP)
TSUJI TSUYOSHI (JP)
KOHSAKA MASANOBU (JP)
YOSHII SHIGEHARU (JP)
SAITO TOMOO (JP)
MASHIKO YOSHIHIRO (JP)
International Classes:
B29C48/305; C08J5/18; B29C48/395; B29C59/04; B32B27/30; C03C27/12; C08F8/28; C08J3/12; C08L29/14; B29K59/00
Domestic Patent References:
| WO2003066690A1 | 2003-08-14 |
Foreign References:
| JPH051108A | 1993-01-08 | |||
| JP2000001514A | 2000-01-07 | |||
| JPH11349769A | 1999-12-21 |
Other References:
See also references of EP 2083039A4
Attorney, Agent or Firm:
SENMYO, Kenji et al. (SIA Kanda Square17, Kanda-konyacho,Chiyoda-ku, Tokyo 35, JP)
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