Production of random or homogeneous copolymers

An oriented film having an elongation at break greater than 50% and a 1% secant modulus greater than 350 kgf/mm.sup.2 in the direction of orientation, made from a homogeneous melt-extrudable copolymer having a reduced viscosity of at least 0.5 but not more than 3 (as measured on a solution of 0.5 g of the copolymer in 100 cm.sup.3 of dimethyl formamide at 25.degree. C.), consisting of 50 to 98 mole % of units of acrylonitrile, 2 to 50 mole % of units of at least one conjugated aromatic olefine which has the formula

• CH.sub.2 :
• CR.Ar
• wherein R is hydrogen or methyl and Ar is an aromatic residue having up to 3 rings or is coumarone or indene, and 0 to 10 mole % of units of other ethylenically unsaturated copolymerizable monomers, the molar ratio of acrylonitrile to conjugated aromatic olefine having about the same value for substantially all the copolymer molecules and units of conjugated aromatic olefine being randomly distributed in the copolymer molecules, the copolymer being the product of a copolymerization reaction under free-radical polymerization conditions in which the conjugated aromatic olefine is fed to the reaction mixture throughout the polymerization at the rate at which polymerization proceeds.

An oriented film made from a homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile, 10 to 50% molar of units of styrene and the molar ratio of acrylonitrile to styrene having about the same value for substantially all of the polymer molecules and said styrene units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium throughout the polymerization at the rate at which polymerization proceeds, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g. of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C., and the film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

An oriented film made from a homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile, 10 to 50% molar of units of styrene and from 1 to 10% of units of other ethylenically unsaturated compounds copolymerized with the acrylonitrile and the styrene, the quantity of the units of said other compounds being less than the quantity of styrene units, the molar proportions of acrylonitrile, styrene and said other ethylenically unsaturated compounds having about the same value for substantially all of the polymer molecules and the units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium during polymerization at the rate at which polymerization proceeds, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C., and the film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

A homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile and 10 to 50% molar of units of styrene, the molar ratio of acrylonitrile to styrene having about the same value for substantially all of the polymer molecules and said styrene units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium throughout the polymerization at a rate dependent on the rate of production of heat in the formation of the copolymer, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g. of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C., and said polymer being capable of forming a melt extruded oriented film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

A homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile, 10 to 50% molar of units of styrene and from 1 to 10% of units of other ethylenically unsaturated compounds copolymerized with the acrylonitrile and the styrene, the quantity of the units of said other compounds being less than the quantity of styrene units, the molar proportions of acrylonitrile, styrene and said other ethylenically unsaturated compounds having about the same value for substantially all of the polymer molecules and the units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium during polymerization at a rate dependent on the rate of production of heat in the formation of the copolymer, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g of the copolymer 100 cm.sup.3 of dimethylformamide at 25.degree. C., and said polymer being capable of forming a melt extruded oriented film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

A homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile, 10 to 50% molar of units of styrene and the molar ratio of acrylonitrile to styrene having about the same value for substantially all of the polymer molecules and said styrene units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium throughout the polymerization at the rate at which polymerization proceeds, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C., and said copolymer being capable of forming, by melt extrusion into a film which is then oriented, an oriented film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

A homogeneous melt extrudable copolymer consisting of 50 to 90% molar of units of acrylonitrile, 10 to 50% molar of units of styrene and from 1 to 10% of units of other ethylenically unsaturated compounds copolymerized with the acrylonitrile and the styrene, the quantity of the units of said other compounds being less than the quantity of styrene units, the molar proportions of acrylonitrile, styrene and said other ethylenically unsaturated compounds having about the same value for substantially all of the polymer molecules and the units being randomly distributed in the polymer molecules, said copolymer being the product of copolymerizing under free radical polymerization conditions in which styrene is fed to the reaction medium during polymerization at the rate at which polymerization proceeds, said copolymer having a reduced viscosity within the range 0.5 to 3 as measured on a solution of 0.5 g of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C., and said copolymer being capable of forming, by melt extrusion into a film which is then oriented, an oriented film having an elongation at break greater than about 50% and a 1% secant modulus greater than 350 kgf in the direction of orientation.

A homogeneous melt extrudable copolymer having a reduced viscosity of at least 0.5 but not more than 3 (as measured on a solution of 0.5 g of the copolymer in 100 cm.sup.3 of dimethylformamide at 25.degree. C.), consisting of 50 to 98 mole % of units of acrylonitrile, 2 to 50 mole % of units of at least one conjugated aromatic olefin which has the formula

• CH.sub.2 :CR.Ar
• wherein R is hydrogen or methyl and Ar is an aromatic residue having up to 3 rings or is coumarone or indene, and 0 to 10 mole % of units of other ethylenically unsaturated copolymerizable monomers, the molar ratio of acrylonitrile to conjugated aromatic olefin having about the same value for substantially all the copolymer molecules and units of conjugated aromatic olefin being randomly distributed in the copolymer molecules, the copolymer being the product of a copolymerization reaction under free radical polymerization conditions in which the conjugated aromatic olefin is fed to the reaction mixture throughout the polymerization at the rate at which polymerization proceeds, said copolymer being capable of forming, by melt extrusion into a film which is then oriented, an oriented film having an elongation at break greater than 50% and a 1% secant modulus greater than 350 kgf/mm.sup.2 in the direction of orientation.