Paper barrier materials

Abstract

To provide a paper-based barrier material with excellent flexibility. [Solution] A paper substrate has a barrier coating layer having water vapor barrier properties or gas barrier properties, followed by a heat seal coating layer, in that order. After folding the paper crosswise with the heat-seal coating layer facing outward, a paper barrier material satisfying at least one of the following (1) or (2) (1) Oxygen permeability at a temperature of 23°C and relative humidity of 0% is 20 ml / m³ 2 ·day · atm or less (2) Water vapor transmission rate at a temperature of 40°C and relative humidity of 90% is 20 g / m³ 2 ·day or less.

Claims

1. The paper substrate has a barrier coating layer with gas barrier properties and a heat-seal coating layer in that order. The aforementioned paper substrate contains bleached pulp and has a basis weight of 25 g / m². ２ 70g / m or more ２ The following: When the heat-seal coating layer is evaluated as a film with a thickness of 50 μm, it has a break point elongation of 200% or more and a Young's modulus of 15 MPa or less. The heat-seal coating layer contains an ethylene-vinyl acetate resin, A paper barrier material characterized by satisfying at least one of the following (1) or (2) after being folded crosswise with the heat-seal coating layer facing outward. (1) Oxygen permeability at a temperature of 23°C and relative humidity of 0% is 20 ml / m³ ２ ・day・atm or less (2) Water vapor transmission rate at a temperature of 40°C and a relative humidity of 90% is 20 g / m³ ２ ・Less than day.

2. The paper barrier material according to claim 1, characterized in that the barrier coating layer contains polyvinyl alcohol.

3. The paper barrier material according to claim 2, characterized in that the polyvinyl alcohol is fully saponified polyvinyl alcohol.

4. The paper barrier material according to any one of claims 1 to 3, characterized in that, when the total content of thermoplastic resin in the heat seal coating layer is 100 parts (solids), it contains 1 to 30 parts (solids) of the ethylene-vinyl acetate resin.

5. The paper barrier material according to claim 4, characterized in that the Tg of the ethylene-vinyl acetate resin is 0°C or lower.

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