Method for preparing an acrylonitrile-based copolymer modified flame retardant and flame retardant fibrous material

摘要

A method for preparing a flame retardant based on modified acrylonitrile copolymer comprising: (a) prepolymerizing a first composition to obtain a first prepolymer solution including a first prepolymer; (B) prepolymerizing a second composition to obtain a second prepolymer solution including a second prepolymer; and (c) mixing the first and the second prepolymer solution and subjecting the mixture of the first and the second prepolymer to polymerization to obtain a copolymer solution based flame retardant containing a modified acrylonitrile-based flame retardant modified acrylonitrile copolymer; the method characterized in that wherein: the first composition includes acrylonitrile, a vinyl monomer containing halogen, at least one monomer hydrophilic vinyl, a polar solvent and a reaction initiator, the vinyl monomer containing halogen include chloride vinylidene; based on the total weight of vinylidene chloride, vinyl monomer and acrylonitrile in the first composition, vinylidene chloride of the first composition is in an amount between 10 and 40% by weight and the monomer hydrophilic vinyl is a quantity between 5 and 50% by weight; the first prepolymer has an average molecular weight of 30,000 to 40,000 weight; the second composition includes acrylonitrile, a vinyl monomer containing halogen, the polar solvent, and the reaction initiator, the vinyl monomer containing halogen second composition includes vinylidene chloride; based on the total weight of vinylidene chloride and acrylonitrile in the second composition, vinylidene chloride of the second composition is in an amount between 40 and 60% by weight; and based flame retardant modified acrylonitrile copolymer has an average molecular weight in weight comprised between 50,000 and 80,000, and contains 30 to 46% by weight of monomer units of vinylidene chloride, from 1 to 5% by weight of monomer units of vinyl hydrophilic, and from 49 to 69% by weight of acrylonitrile monomer units based on the total weight of monomer units of vinylidene chloride monomer units and hydrophilic vinyl monomer units acrylonitrile copolymer modified acrylonitrile-based flame retardant.