HEAT-SHRINKABLE POLYESTER FILM AND PROCESS FOR PRODUCTION THEREOF

Title:

HEAT-SHRINKABLE POLYESTER FILM AND PROCESS FOR PRODUCTION THEREOF

Document Type and Number:

WIPO Patent Application WO/2007/145231

Kind Code:

A1

Abstract:

A heat-shrinkable polyester film which causes the main shrinkage in the lengthwise direction and which is controlled in such a way that the lengthwise and widthwise heat shrinkage factors observed when treated in warm water of 90°C for 10 seconds, the lengthwise and widthwise refraction indexes, and the natural shrinkage factor observed after the aging at 40°C and 65%RH for 700 hours fall within prescribed ranges respectively. The heat-shrinkable polyester film can be produced by stretching an unstretched film at a temperature ranging from the Tg plus 5°C to the Tg plus 40°C at a draw ratio of 2.5 to 6.0 in the widthwise direction, passing the resulting film through an intermediate zone not accompanied with positive heating, heat-treating the film at 100 to 170°C for 1.0 to 10.0 seconds, cooling the film to lower the surface temperature of the film to a temperature of 30 to 70°C, stretching the film at a temperature ranging from the Tg plus 5°C to the Tg plus 80°C at a draw ratio of 2.0 to 7 in the lengthwise direction, and then cooling the film at a cooling rate of 30 to 70°C/sec to lower the surface temperature of the film to a temperature of 45 to 75°C.

Inventors:

ENDO TAKUROU (JP)
HARUTA MASAYUKI (JP)
TABOTA NORIMI (JP)
NOSE KATSUHIKO (JP)

Application Number:

PCT/JP2007/061860

Publication Date:

December 21, 2007

Filing Date:

June 13, 2007

Export Citation:

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Assignee:

TOYO BOSEKI (JP)
ENDO TAKUROU (JP)
HARUTA MASAYUKI (JP)
TABOTA NORIMI (JP)
NOSE KATSUHIKO (JP)

International Classes:

B29C61/06; B29C55/14; C08J5/18

Foreign References:

JP2005194466A	2005-07-21
JP2007016120A	2007-01-25
JP2007056156A	2007-03-08
JP2006181899A	2006-07-13
JPH08244114A	1996-09-24
JPH08244114A	1996-09-24

Other References: