Dupont Canada Inc.

Other

Exopack Preformance Films Inc.

Theodore J Lang

Kevin Bergevin

Benjamin Andrew Smillie

Divya Chopra

Sumita Sanjeevi Ranganathan

Bernard J Kershaw

Marek Andrej Szymula

A coating composition for use as a surface coating for polymer release films for use in at least one of high temperature and high humidity applications, which comprises a solution of at least one hydroxypropyl methylcellulose having hydroxypropyl molar substitution of from 0 to about 0.82 in combination with at least one water-borne fluorochemical additive selected from perfluoralkyl methacrylic acid copolymers.

High temperature and high humidity release coating for polymer film

The present invention relates to a release coating composition that may be applied to a film that may then be used as a substrate useful for applications requiring release for a broad range of temperatures and high humidity conditions, which temperatures may range from about 20&deg; C. to about 210&deg; C. These applications include release substrate used in the manufacture of calendared cured sheet rubber and molding paste composites, such as sheet molding compound (SMC), thick molding compound (TMC), bulk molding compound (BMC) and fiberglass composites. The release coating composition comprises a solution of a hydroxypropyl methylcellulose having hydroxypropyl molar substitution of from 0 to about 0.82. In a preferred form, particulate solids are present in the composition.

A transversely tearable film and pouches made therefrom are disclosed. The transversely tearable laminate comprises a machine direction oriented linear low density polyethylene film adhesively laminated on at least one side to a sealant film, the sealant film having an Elmendorf tear in the machine direction of at least about 2 g/.mu.m, and the selection of said oriented film and said sealant film being made on the basis that:

Film laminate with easy TD tear

A transversely tearable film and pouches made therefrom are disclosed. The transversely tearable laminate comprises a machine direction oriented linear low density polyethylene film adhesively laminated on at least one side to a sealant film, the sealant film having an .Elmendorf tear in the machine direction of at least about 2 g/.mu.m, and the selection of said oriented film and said sealent film being made on the basis that:

FIlm laminate with easy to tear

A film laminate comprising a base film and a first sealant web with a coating of polyvinylidene chloride (PVDC) sandwiched therebetween is disclosed. The first sealant web is selected from the group consisting of (a) film made from a copolymer of ethylene and vinyl acetate, and (b) a film made from a blend of (i) a copolymer of ethylene and vinyl acetate with (ii) a homopolymer of ethylene, or a copolymer of ethylene and one or more C.sub.4 to C.sub.10 .alpha.-olefins, said homopolymer or copolymer having a density of from about 0.915 to about 0.955 g/cm.sup.3, or blends of said homopolymer and copolymer. The base film is selected from the group consisting of oriented nylon film, oriented polyester film, oriented polypropylene film and a second sealant web, said second sealant web being selected from the same group as said first sealant web and having a slip coefficient of less than about 0.4. The PVDC coating consists of at least one layer, the layers being characterized by having a crystallinity index of less than 1.15 if dried and allowed to stand for 30 days at 20.degree. C. and, if the base film is selected from nylon film, polyester film or polyproylene film, the layer in contact with the base film being further characterized by having a crystallinity index of from 1.12 to 1.25 if dried and allowed to stand for 5 days at 40.degree. C. A process for forming the laminate is also disclosed. The process comprises bringing the base film and the first sealant web together between a nip roll and a hot roll, said PVDC coating having been applied to at least the base film or the first sealant web, with the provisio that if the first or second sealant web is in contact with the hot roll then said web which contacts the hot roll has a slip coefficient of less than about 0.4. The laminates may be used for packaging comestibles e.g. bacon, weiners and cheese.

Process for forming a sealant WEB-PVDC-base film laminate

A process for coating nylon film with polyvinylidene chloride is disclosed, comprising primer-coating the nylon film with an aqueous dispersion of a vinylidene chloride copolymer having a crystallinity index of less than 1.15 after 30 days' storage at 20.degree. C. and between about 1.05 and 1.20 when stored for 48 hours at 40.degree. C.; drying the primer-coated film; coating the primer-coated film with an aqueous dispersion of a vinylidene chloride copolymer capable of developing crystallinity to a level sufficient that the crystalline vinylidene chloride copolymer so-formed resists attack by an organic solvent, as measured by the Solvent Haze Test; and drying the coated film. During primer-coating and the first drying step, the film is kept under sufficient tension to prevent curling of the film. The coated film may be laminated to polyethylene to provide a laminate useful for packaging of processed food.

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Kingston, Canada

Theodore J Lang