Heat-sealable composite polymeric film

摘要

A sealed container containing a foodstuff or beverage has a lid that includes a heat-sealable, composite film that includes a polymeric substrate layer having a first and second surface, a primer layer that includes PVdC disposed on the first surface, and a heat-sealable polymeric layer extrusion coated on the primer layer. The heat-sealable polymeric layer is 12 μm thick or less and includes a copolymer having repeating monomeric units of ethylene and at least a second type of repeating monomeric unit having the formula [—CH2C(R1)(X)—] wherein:
X is selected from —COOR2 and —OC(O)CH3;R1 =H or methyl; andR2 is H, C1-10 alkyl or a counterion M.

主权项

1. A sealed container containing a foodstuff or beverage, said container comprising a lid comprising a heat-sealable, peelable composite film comprising a polyester substrate layer having a first and second surface, a primer layer comprising a polymeric material and disposed on and in direct contact with the first surface of the polyester substrate layer, and a heat-sealable polymeric layer extrusion coated on the primer layer, wherein
(i) the polymeric material of the primer layer comprises poly(vinylidene chloride) (PVdC); (ii) the thickness of the primer layer is in the range of 0.01 to 0.2 μm; (iii) the polymeric material of the heat-sealable polymeric layer consists of a copolymer comprising repeating monomeric units of ethylene [—CH2CH2—] and at least a second type of repeating monomeric unit derived from acrylic acid, methacrylic acid and vinyl acetate having the formula [—CH2C(R1)(X)—] wherein:
X is selected from the group consisting of —COOR2 and —OC(O)CH3;R1=H or methyl; and R2 is selected from the group consisting of H, C1-10 alkyl and a counterion M; and wherein the heat-sealable polymeric layer contains only a single type of said copolymer; (iv) the thickness of the heat-sealable layer is 12 μm or less; and (v) the water vapour transmission rate of the heat-sealable, peelable composite film is in a range of 1g/100 inches2/day to 10g/100 inches2/day.