JPWO2021039646A5 - - Google Patents

Claims (9)

A substrate (X), an inorganic deposition layer (Y) and an overcoat layer (Z) are provided in this order,
The substrate (X) is made of a biaxially stretched polyvinyl alcohol resin film,
The overcoat layer (Z) contains a modified polyvinyl alcohol (A) having a vinyl alcohol unit (a) and a monomer unit (b) having a polar group other than the vinyl alcohol unit (a),
The thickness of the overcoat layer (Z) is 0.003 μm or more and 5 μm or less,
The proportion of monomer units (b) having a polar group in all monomer units constituting the modified polyvinyl alcohol (A) is 0.05 mol% or more and 30 mol% or less,
A multilayer structure in which the content of the modified polyvinyl alcohol (A) in the overcoat layer (Z) is 70% by mass or more . 2. The multilayer structure according to claim 1 , wherein said polar group is at least one selected from the group consisting of a carboxy group, an ester group and a silanol group. 3. The multilayer structure according to claim 1, wherein the maximum intensity ratio (I(B)/I(C) _MAX ) determined by the following procedures (1) to ( 3) is 1.20 or more.
(1) Analysis in the depth direction by TOF-SIMS is performed at five arbitrarily selected points on the surface of the overcoat layer (Z).
(2) For each detected fragment, the average value of the maximum intensity of the fragment at each measurement point (I (B)), and the intermediate measurement point between the measurement start point and the maximum intensity measurement point at each measurement point The average intensity value (I(C)) is obtained, and the ratio between them is defined as the intensity ratio (I(B)/I(C)).
(3) The maximum intensity ratio (I(B)/I(C) _{MAX ) among the determined intensity ratios (I(B)/I(C)) for each fragment is defined as the maximum intensity ratio (I(B)/I(C) MAX} ). 4. The multilayer structure according to any one of claims 1 to 3 , further comprising a layer (J) other than the substrate (X), the inorganic deposition layer (Y) and the overcoat layer (Z). At least two other layers (J) are provided, and a base material (X), an inorganic vapor deposition layer (Y) and an overcoat layer (Z) are provided between the at least two other layers (J). Item 5. The multilayer structure according to item 4 . The biaxially stretched polyvinyl alcohol resin film is a biaxially stretched film mainly composed of an ethylene-vinyl alcohol copolymer having an ethylene unit content of 10 mol% or more and 65 mol% or less and a saponification degree of 90 mol% or more. , the multilayer structure according to any one of claims 1 to 5 . JIS K7126 under the conditions of 40°C, 0% RH (carrier gas side), 90% RH (oxygen supply side) after repeated reciprocating motion three times in the Gelbo Fleck test in accordance with ASTM F 392. 7. The multilayer structure according to any one of claims 1 to 6 , which has an oxygen permeability of 2.0 ml/(m ² ·day · atm) or less as measured by . A vacuum packaging bag comprising the multilayer structure according to any one of claims 1 to 7 . A vacuum insulator, comprising: the vacuum packaging bag according to claim 8 ; and a core material arranged inside said vacuum packaging bag, wherein said interior is decompressed.