bag

Abstract

To provide a bag that is puncture-resistant and heat-resistant. [Solution] The laminate constituting the bag having a steam venting mechanism comprises at least a first substrate, a second substrate, and a sealant layer in this order. The laminate further comprises a transparent vapor-deposited layer provided on the first or second substrate between the first and second substrates, and a transparent gas barrier coating film provided on the transparent vapor-deposited layer. Of the first and second substrates, one contains polyethylene terephthalate, and the other contains polybutylene terephthalate. The substrate containing polybutylene terephthalate has a single-layer structure, and the IV value of polybutylene terephthalate is 1.10 dl / g or more and 1.35 dl / g or less.

Claims

[Claim 1] A bag having a steam release mechanism, The laminate constituting the bag includes at least a first base material, a second base material, and a sealant layer (excluding the sealant layer described in (a) below and the sealant layer described in (b) below) in this order. The laminate further includes a transparent vapor-deposited layer provided on the first substrate or the second substrate between the first substrate and the second substrate, and a transparent gas barrier coating film provided on the transparent vapor-deposited layer. Of the first and second substrates, one contains 51% by mass or more of polyethylene terephthalate, and the other contains 51% by mass or more of polybutylene terephthalate. The first substrate and the second substrate, the one containing polybutylene terephthalate, have a single-layer structure, and the IV value of polybutylene terephthalate is 1.10 dl / g or more and 1.35 dl / g or less. The sealant layer is a single layer, The sealant layer comprises polypropylene and polyethylene. The aforementioned polypropylene is a bag containing a propylene-ethylene block copolymer. (a) A sealant layer comprising a polypropylene film comprising the following polymers (a) 70-90% by weight, polymer (b) 2-10% by weight, polymer (c) 2-10% by weight, and polymer (d) 3-20% by weight (provided that the total weight of the polymers is 100% by weight), characterized in that the haze of the film is 8-30%. Polymer (a): A propylene-ethylene block copolymer obtained by polymerizing a monomer mainly composed of propylene in the absence of an inert solvent in the first step to produce a polymer portion (component a1), and then by polymerization in the gas phase in the second step to produce an ethylene-propylene copolymer portion (component a2), wherein the content of component a2 is 15 to 25% by weight (where the total of components a1 and a2 is 100% by weight), and the ratio of the intrinsic viscosity of component a2 ([h]a2) to the intrinsic viscosity of component a1 ([h]a1) ([h]a2 / [h]a1) is 0.8 to 1.

5. Polymer (b): Density of 0.91–0.97 g / cm³ 3 and an ethylene polymer with a melt flow rate of 5 to 30 g / 10 min. Polymer(c): Density of 0.86–0.90 g / cm³ 3 Furthermore, the melt flow rate is 0.3 to 5 g / 1O min of ethylene-α-olefin random copolymer. Polymer (d): A propylene polymer consisting of two or more propylene polymers with different molecular weights, wherein the intrinsic viscosity ([h]d1) of the component with the highest molecular weight (component d1) is 5 dl / g or more and less than 1 0 dl / g, and is at least twice the intrinsic viscosity ([h]d) of the entire polymer (d). (b) A retort-compatible polypropylene film comprising a film in which 96 to 99 wt% is propylene-ethylene block copolymer and 1 to 4 wt% is high-density polyethylene, characterized in that the propylene-ethylene block copolymer has the properties specified in (a) to (c) below, including a sealant layer (a) The melting point is between 157 and 164°C. (b) The xylene-soluble content is 16-25%. (c) MFR is 1.0 to 3.0 g / 10 mins

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