Diafoil Company, Ltd.

Diafoil Hoechst Company, Limited

Shinobu Suzuki

Yujiro Fukuda

Shigeo Utsumi

Kazuo Endo

Megumi Komiyama

A heat sensitive original sheet for stencil printing made of a laminate of a paper sheet and a biaxially oriented polyester film having a melting point of 150.degree. to 240.degree., a thickness of 0.2 to 3 .mu.m, an average refractive index of 1.570 to 1.578, a thermal shrinkage stress of 100 to 800 g/mm.sup.2 after being treated at 80.degree. C. for 10 seconds, a thermal shrinkage factor of 5 to 50% after being treated at 80.degree. C. for 10 minutes, a shrinkage factor of 15% or less after being treated in toluene at 25.degree. C. for 10 minutes, and a center line average surface roughness of 0.02 to 0.3 .mu.m, which original sheet is excellent in a perforation sensitivity, resistance to curling, and resolution and image density of a printed image.

Polyester film comprising a mixture of polyesters for highly heat

A shrinkable copolyester film having shrinkage of not less than 30% in the direction (main shrink direction) of either the machine direction or the transverse direction after 5 min treatment in an air oven at 100.degree. C., a shrinkage of not more than 20% in the other direction perpendicular to the main shrink direction after 5 min treatment in an air oven at 100.degree. C., an initial shrinkage stress (F.sub.0) of not more than 2000 g/mm.sup.2 in the main shrink direction during the course of 5 sec after dipped in a silicone oil of 75.degree. C., a shrinkage stress (F.sub.20) of not less than (F.sub.0 -100) g/mm.sup.2, after 20 sec dipping in a silicone oil at 75.degree. C., and a glass transition temperature of 35.degree. to 65.degree. C., is disclosed. The shrinkable copolyester film of the present invention is excellent in shrinkage properties, i.e., substantially free from wrinkles, distortion of film and uneven shrinkage, and is suitable for a shrinkable label for a PET bottle, etc.

Shrinkable copolyester film

Disclosed in this invention is a shrinkable polyester film having a shrinkage of not less than 40% after 5-minute treatment in a 100.degree. C. air oven in one of the machine and transverse directions, and a shrinkage of not more than 15% after 5-minute treatment in a 100.degree. C. air oven and a maximum shrinkage stress of not more than 50 g/mm.sup.2 at 40.degree. to 100.degree. C. in the other direction. The shrinkable film of this invention has the excellent shrink characteristics and are substantially free from wrinkling, curling at the end and non-uniformity of shrinkage when the film is shrunk, so that it is suited for use as a label film and has a high industrial value.

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Machida, Japan

Shinobu Suzuki