Patent ES-8604450-A1 (ES)
Title: Oriented multilayer heat sealable packaging film and method of forming same.
IPC: C08J7/052
Filed: 1984-06-16
Abstract: EP--88535 A Multilayer heat sealable structure comprises (in order) (a) a polyolefin film substrate (b) a layer of a random copolymer of ethylene and propylene contg. 0.5-6 wt.% ethylene (c) a primer coating and (d) a heat sealable layer of vinylidene chloride copolymer contg. at least 50 wt.% vinylidene chloride. - Pref. the substrate film is a polypropylene homopolymer interblended with 0-15 pts.wt. of the copolymer and the copolymer layer is e.g. coextruded on the substrate and the substrate and copolymer are biaxially oriented or the substrate is biaxially oriented and the copolymer layer is uniaxially oriented. - The prods. are esp. useful in the prodn. of packaging materials showing improved heat seal strength and allows prodn. of packaged (food) prods. in which the bags have reduced tendency to split or burst at the seams e.g. during shipment. EPAB- EP--88535 B Multilayer heat sealable structure comprises (in order) (a) a polyolefin film substrate (b) a layer of a random copolymer of ethylene and propylene contg. 0.5-6 wt.% ethylene (c) a primer coating and (d) a heat sealable layer of vinylidene chloride copolymer contg. at least 50 wt.% vinylidene chloride. - Pref. the substrate film is a polypropylene homopolymer interblended with 0-15 pts.wt. of the copolymer and the copolymer layer is e.g. coextruded on the substrate and the substrate and copolymer are biaxially oriented or the substrate is biaxially oriented and the copolymer layer is uniaxially oriented. - The prods. are esp. useful in the prodn. of packaging materials showing improved heat seal strength and allows prodn. of packaged (food) prods. in which the bags have reduced tendency to split or burst at the seams e.g. during shipment. (16pp) - EP--88535 B An oriented multilayer heat sealable structure comprising: (a) a substrate comprising a polyolefin film (b) a layer on at least one surface of (a), the layer consisting essentially of a random copolymer of ethylene and propylene, the copolymer containing from 0.5 to 6% by weight of ethylene (c) a primer coating on at least one layer (b) and (d) a heat sealable layer on coating (c), the heat sealable layer comprising a vinylidene chloride copolymer containing at least 50% by weight of vinylidene chloride. (9pp)t USAB- US4447494 A Heat sealable structures consist of (A) a polyolefin substrate, (B) a layer of a random copolymer of propylene contg. 0.5-6 wt % ethylene on at least 1 side of (A), (C) a primer coating between (B) and (D) and on at least 1 side of (B), and D) a heat sealable layer of a copolymer contg. at least 50 wt % vinylidene chloride. - Layer (A) pref. consists of polypropylene blended with 0-15 wt % of copolymer (B). The copolymer is pref. extruded onto (A) and the two biaxially oriented. The primer is pref. the reaction product of an acidified aminoethylated vinyl polymer and an epoxy resin. - The materials are sufficiently strong and have a sufficient seal strength to allow prodn. of large bags to hold large amts. of goods. (6pp)d - US4495027 A Prodn. of a thermally sealed laminate film comprises co-extrusion of a polypropylene layer with a random copolymer of ethylene and propylene (94-99.5 wt.%) on one or both sides this substrate is orientated biaxially, and a prime coating is applied to the random copolymer surface(s) a coating of copolymer obtd. from vinylidene chloride (at least 50 wt.%) is applied to the primer surface and the laminate is aged and sealed at about 32-150 deg.F for periods of about 21 days to 24 hr.