The present invention provides a method of preparing an aromatic vinyl-unsaturated nitrile-based copolymer in which, when an aromatic vinyl-unsaturated nitrile-based copolymer in which a content of a structural unit derived from unsaturated nitrile monomers in the copolymer is in the range of 22 to 30 wt % is prepared, oligomer content and unreacted monomer content are decreased, resulting in excellent heat resistance, significantly improved surface quality, and particularly, reduced generation of residue on a product surface when used in a closed high temperature environment and reduced occurrence of mold deposits during injection molding, and an aromatic vinyl-unsaturated nitrile-based copolymer prepared using the method.

The present invention provides a method of preparing an aromatic vinyl-unsaturated nitrile-based copolymer in which, when an aromatic vinyl-unsaturated nitrile-based copolymer in which a content of a structural unit derived from unsaturated nitrile monomers in the copolymer is in the range of 22 to 30 wt % is prepared, oligomer content and unreacted monomer content are decreased, resulting in excellent heat resistance, significantly improved surface quality, and particularly, reduced generation of residue on a product surface when used in a closed high temperature environment and reduced occurrence of mold deposits during injection molding, and an aromatic vinyl-unsaturated nitrile-based copolymer prepared using the method.

A water dispersion of a vinyl halide copolymer is synthesized by a method including at least one of each of: an emulsion polymerization step A in which a monomer group used as a raw material has an n-octanol/water partition coefficient (log Pow) with an average value of 2.2 or less; and an emulsion polymerization step B in which a monomer group used as a raw material includes a vinyl halide monomer and a copolymerization monomer having a reactivity ratio r1 with vinylidene chloride of less than 0.7 and in which a mass proportion of the vinyl halide monomer among 100 mass % of the monomer group is 60 mass % or more. A mass proportion of structural units derived from the copolymerization monomer having a reactivity ratio r1 of less than 0.7 is 4 mass % or more relative to 100 mass % of total mass of a polymer synthesized in step B.

A water dispersion of a vinyl halide copolymer is synthesized by a method including at least one of each of: an emulsion polymerization step A in which a monomer group used as a raw material has an n-octanol/water partition coefficient (log Pow) with an average value of 2.2 or less; and an emulsion polymerization step B in which a monomer group used as a raw material includes a vinyl halide monomer and a copolymerization monomer having a reactivity ratio r1 with vinylidene chloride of less than 0.7 and in which a mass proportion of the vinyl halide monomer among 100 mass % of the monomer group is 60 mass % or more. A mass proportion of structural units derived from the copolymerization monomer having a reactivity ratio r1 of less than 0.7 is 4 mass % or more relative to 100 mass % of total mass of a polymer synthesized in step B.

A water dispersion of a vinyl halide copolymer is synthesized by a method including at least one of each of: an emulsion polymerization step A in which a monomer group used as a raw material has an n-octanol/water partition coefficient (log Pow) with an average value of 2.2 or less; and an emulsion polymerization step B in which a monomer group used as a raw material includes a vinyl halide monomer and a copolymerization monomer having a reactivity ratio r1 with vinylidene chloride of less than 0.7 and in which a mass proportion of the vinyl halide monomer among 100 mass % of the monomer group is 60 mass % or more. A mass proportion of structural units derived from the copolymerization monomer having a reactivity ratio r1 of less than 0.7 is 4 mass % or more relative to 100 mass % of total mass of a polymer synthesized in step B.

The present invention provides a method of preparing an aromatic vinyl-unsaturated nitrile-based copolymer in which, when an aromatic vinyl-unsaturated nitrile-based copolymer in which a content of a structural unit derived from unsaturated nitrile monomers in the copolymer is in the range of 22 to 30 wt % is prepared, oligomer content and unreacted monomer content are decreased, resulting in excellent heat resistance, significantly improved surface quality, and particularly, reduced generation of residue on a product surface when used in a closed high temperature environment and reduced occurrence of mold deposits during injection molding, and an aromatic vinyl-unsaturated nitrile-based copolymer prepared using the method.

The present invention provides a method of preparing an aromatic vinyl-unsaturated nitrile-based copolymer in which, when an aromatic vinyl-unsaturated nitrile-based copolymer in which a content of a structural unit derived from unsaturated nitrile monomers in the copolymer is in the range of 22 to 30 wt % is prepared, oligomer content and unreacted monomer content are decreased, resulting in excellent heat resistance, significantly improved surface quality, and particularly, reduced generation of residue on a product surface when used in a closed high temperature environment and reduced occurrence of mold deposits during injection molding, and an aromatic vinyl-unsaturated nitrile-based copolymer prepared using the method.

An aqueous latex [latex (L)] of a vinylidene chloride copolymer [copolymer (A)], wherein the copolymer (A) consists essentially of recurring units derived from vinylidene chloride (VDC) in an amount comprised between 89.0 and 91.0 wt % of the copolymer, recurring units derived from methacrylonitrile (MAN) in an amount comprised between 2.00 and 5.50 wt % of the copolymer, recurring units derived from at least one ionic comonomer (ICO) in an amount comprised between 0.5 and 1.4 wt % of the copolymer (A), and recurring units derived from methylmethacrylate (MMA) in an amount such that the total of recurring units of VDC, MAN, ICO and MMA is 100 wt %,
and wherein the latex (L) comprises at least one surfactant [surfactant (S)] in an amount comprised between 0.09 and 1.50 wt % of the copolymer (A). Process for the manufacture of the aqueous latex (L), film made therefrom and retort pouch prepared with such film.

An aqueous latex [latex (L)] of a vinylidene chloride copolymer [copolymer (A)], wherein the copolymer (A) consists essentially of recurring units derived from vinylidene chloride (VDC) in an amount comprised between 89.0 and 91.0 wt % of the copolymer, recurring units derived from methacrylonitrile (MAN) in an amount comprised between 2.00 and 5.50 wt % of the copolymer, recurring units derived from at least one ionic comonomer (ICO) in an amount comprised between 0.5 and 1.4 wt % of the copolymer (A), and recurring units derived from methylmethacrylate (MMA) in an amount such that the total of recurring units of VDC, MAN, ICO and MMA is 100 wt %,
and wherein the latex (L) comprises at least one surfactant [surfactant (S)] in an amount comprised between 0.09 and 1.50 wt % of the copolymer (A). Process for the manufacture of the aqueous latex (L), film made therefrom and retort pouch prepared with such film.

An aqueous latex [latex (L)] of a vinylidene chloride copolymer [copolymer (A)], wherein the copolymer (A) consists essentially of recurring units derived from vinylidene chloride (VDC) in an amount comprised between 89.0 and 91.0 wt % of the copolymer, recurring units derived from methacrylonitrile (MAN) in an amount comprised between 2.00 and 5.50 wt % of the copolymer, recurring units derived from at least one ionic comonomer (ICO) in an amount comprised between 0.5 and 1.4 wt % of the copolymer (A), and recurring units derived from methylmethacrylate (MMA) in an amount such that the total of recurring units of VDC, MAN, ICO and MMA is 100 wt %,
and wherein the latex (L) comprises at least one surfactant [surfactant (S)] in an amount comprised between 0.09 and 1.50 wt % of the copolymer (A). Process for the manufacture of the aqueous latex (L), film made therefrom and retort pouch prepared with such film.