| 摘要 |
1281194 Packaging materials for foodstuffs and medicines MONSANTO CO 14 Nov 1969 [15 Nov 1968] 55776/69 Heading B8C [Also in Division C3] A packaging material for foodstuffs or medicines comprises a polymer of 70-98% by weight methacrylonitrile with a mono-ethylenically unsaturated aromatic compound, the polymer having an oxygen permeability of no more than 3 c.c./100 sq.cm./24 hr./atmos./mil. at 73‹ F., and a water vapour permeability of no more than 3 gm./24 hr./100 sq.cm./mil. at 73‹ F. The polymer may be a co-polymer of the above constituents, or be a graft polymerization on to a rubber of a monomer mixture of the above constituents, or be a blend of copolymer and graft polymer. The polymer may be biaxially orientated and be formed in sheets or containers. The monoethylenically unsaturated aromatic compound has the formula where R 1 is hydrogen, a halogen or an alkyl radical, and R 2 is a substituted or unsubstituted aromatic radical having 6-10 carbon atoms in the ring, e.g. styrene alpha methyl styrene, vinyl toluene, alpha chloro-styrene, parachloro styrene, ortho methyl styrene, para methyl styrene, ethyl styrene, isopropyl styrene, dichloro styrene, or vinyl napthalene. |
