Synthetic paper pulp contg. acrylonitrile copolymers - with vinyl alcohol and with styrene, giving opaque, re-cyclable paper opt. with wood pulp

摘要

A synthetic fibrous pulp is prepd. from a compsn. contg. (A) 5-40 wt.% of a graft copolymer contg. (a) 20-80 (35-65) wt.% PVA and (b) 80-20 wt.% acrylonitrile and (B) 95-60 wt.% of a copolymer contg. (c) 55-95 (60-85) wt.% styrene and (d) 45-5 wt.% acrylonitrile. The fibres have a self-bonding microstructure with micro-fibrils with min. dia. 0.01-5 (0.05-3)mu. The pulp may be used alone or with wood pulp, for the mfr. of paper. Synthetic paper produced from the synthetic pulp and wood pulp is in a wt. ratio of 3:97-80:20. The pulp is formed under the mild conditions used for wood pulp and does not require the more rigorous conditions normally needed for synthetic fibres. The paper has good opacity, dimensional stability in the wet state, wet strength and low gas permeability. The paper can easily be recycled for re-pulping. The fibres are easily dispersible in water and have good bonding; fibrillation being easy.