Abstract: A transparent polyester film having excellent antistatic properties, which are little effected with variation of the humidity, and further having excellent flexing resistance, pinhole resistance and printability, which is made from a mixture comprising (i) a polyester consisting essentially of a residue of dibasic acids wherein at least 80% by mol is terephthalic acid and a residue of at least one glycol and (ii) a block copolyester consisting of a crystalline polyester segment having a high melting point and a soft polymer segment having a low melting point and a number average molecular weight of 400 to 8,000, said soft polymer segment having a low melting point being contained in an amount of 0.

Abstract: A process for preparing a biaxially stretched film of a polyamide blend, which comprises (1) melt extruding a polyamide blend to make an unstretched film and (2) stretching the unstretched film first in the machine direction and then in the transverse direction, or (2') stretching the unstretched film first to make a uniaxially stretched film having a plane orientation index of about 0.6 to 1.7 and then stretching the uniaxially stretched film in a direction substantially at a right angle to the direction at the previous stretching, said polyamide blend comprising 97 to 80% by weight of an .alpha.-type aliphatic polyamide (Component A) and 3 to 20% by weight of at least one polyamide (Component B) selected from the group consisting of (i) an .alpha.-type aliphatic polyamide different from the Component A, (ii) a .gamma.

Abstract: A process for preparing a biaxially stretched film of polyamide blend, which comprises (1) extruding a polyamide blend in melt to make an unstretched film and (2) stretching the unstretched film first in a machine direction with a stretch speed of about 40,000 to 60,000,000 %/minute in a draw ratio of about 2 to 6 and then in a transverse direction with a stretch speed of about 500 to 100,000 %/minute in a draw ratio of about 2 to 6, or (2') stretching the unstretched film first to make a uniaxially stretched film having a plane orientation index of about 0.6 to 1.

Abstract: A transparent polyester film having excellent printability, flexing resistance and pinhole resistance and further excellent interlaminar strength, which is made from a polymer mixture or blend comprising (i) a polyester consisting essentially of a residue of dibasic acids wherein at least 80 % by mol is terephthalic acid and a residue of at least one glycol and (ii) a block copolyester consisting of a crystalline polyester (hard) segment having a high melting point and a soft polymer segment having a low melting point and a number average molecular weight of 400 to 8,000, said soft polymer segment having a low melting point being contained in an amount of 0.5 to 10 % by weight on the basis of the whole weight of the polymer mixture or blend, and said crystalline polyester segment having a melting point of at least 170.degree. C when a polymer is produced by the monomers composing the segment alone and said soft polymer segment having a melting or softening point of 100.degree. C or lower.