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AssigneeHoechst Aktiengesellschaft
InventorsHarald Schenk, Hermann Winter, Walter Spietschka
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Disclosed is a packaging material comprising a base layer of cellulose hydrate having on one surface a film coating which is impervious to water vapor, water and oxygen and which comprises a vinylidene chloride copolymer containing from about 90 to 92 percent by weight of vinylidene chloride, from about 5.5 to 7 percent by weight of acrylonitrile, from about 1.5 to 3.5 percent by weight of methyl methacrylate and from about 0.5 to 1.5 percent by weight of itaconic acid, said copolymer having a relative viscosity of about 1.04 measured at 23.degree. C. in a 0.1 percent strength by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and a relative viscosity of 2.8 measured at 23.degree. C. in a 3 percent by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and said film coating having a thickness corresponding to a weight per unit area in the range between about 3 and 10 g/m.sup.2. Also disclosed are a sausage casing of such material and a method for producing same.
A packaging material comprising a base layer of cellulose hydrate having on one surface a film coating which is impervious to water vapor, water and oxygen and which comprises a vinylidene chloride copolymer containing from about 90 to 92 percent by weight of vinylidene chloride, from about 5.5 to 7 percent by weight of acrylonitrile, from about 1.5 to 3.5 percent by weight of methyl methacrylate and from about 0.5 to 1.5 percent by weight of itaconic acid, said copolymer having a relative viscosity of about 1.04 measured at 23.degree. C. in a 0.1 percent strength by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and a relative viscosity of 2.8 measured at 23.degree. C. in a 3 percent by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and said film coating having a thickness corresponding to a weight per unit area in the range between about 3 and 10 g/m.sup.2.
A process for the manufacture of packaging material, which comprises the steps of drawing a tubing of cellulose hydrate from a stock roll, applying a liquid lacquer solution to one side of the moving tubing, said solution containing a copolymer comprising from about 90 to 92 percent by weight of vinylidene chloride, from about 5.5 to 7 percent by weight of acrylonitrile, from about 1.5 to 3.5 percent by weight of methyl methacrylate and from about 0.5 to 1.5 percent by weight of itaconic acid, said copolymer having a relative viscosity of about 1.04, measured at 23.degree. C. in a 0.1 percent strength by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, and a relative viscosity of about 2.8, measured at 23.degree. C. in a 3 percent strength by weight solution in a mixture of tetrahydrofuran and toluene in the ratio of 70:30, levelling the lacquer to a predetermined thickness and drying it to give a film coating which comprises said copolymer having a thickness corresponding to a weight per unit area in the range between about 3 and 10 g/m.sup.2.
Dependencies are inferred from the claim text.