公开(公告)号：US4798875A

公开(公告)日：1989-01-17

申请号：US141340

申请日：1987-12-01

申请人： Kuniyoshi Itoyama ,  Norihiro Horita ,  Shigemi Seki ,  Satoyuki Minami

发明人： Kuniyoshi Itoyama ,  Norihiro Horita ,  Shigemi Seki ,  Satoyuki Minami

IPC分类号： B29C55/00 ,  B29C55/12 ,  C08J5/18 ,  C08L67/02

CPC分类号： C08J5/18 ,  B29C55/005 ,  B29C55/12 ,  C08L67/02 ,  B29K2067/00 ,  C08J2367/02 ,  Y10S428/91

摘要： Disclosed is a biaxially oriented polyester film composed mainly of a polymer blend comprising [A] a polyester having recurring units of the following general formula (I): ##STR1## wherein n is 2, 4 or 6 and R is at least one member selected from the group consisting of ##STR2## in which X is H or Cl and at least one X is Cl, and [B] a copolyester having units represented by the general formula (I) and units represented by the following general formula (II) and/or the following general formula (III): ##STR3## wherein R.sup.I, R.sub.II and R.sup.III stand for at least one member selected from the group consisting of 1,3-phenylene, 1,4-phenylene, 2,6-naphthalene, 2,7-naphthalene, ##STR4## and having a flow-initiating temperature not higher than 350.degree. C. and a melt anisotropy-forming capacity, the molar ratio of the units represented by the general formula (II) and/or the general formula (III) being 0.5 to 18 mole % based on the total polymer blend.One plane of the crystal of the polyester [A] is plane-oriented in the film surface, the in-plane orientation index is 0.75 to 0.95, and the crystal size in the crystal plane direction is 35 to 75 .ANG..