Film including solvent barrier and primer layer
Films including solvent barriers and primer layers are described. In particular, films including a substrate, the substrate including polylactic acid, a primer layer disposed on the substrate, a barrier layer disposed on the surface of the primer layer opposite the substrate, and an adhesive layer disposed on a surface of the barrier layer opposite the primer layer. The barrier layer includes an amorphous aliphatic polyamide with a glass transition temperature of at least 40 #C. Such films can provide acceptable adhesion and barrier performance to polylactic acid based graphics film systems.
1 . A film, comprising:
a substrate, the substrate including polylactic acid;
a primer layer disposed on the substrate;
a barrier layer disposed on a surface of the primer layer opposite the substrate; and
an adhesive layer disposed on a surface of the barrier layer opposite the primer layer;
wherein the barrier layer includes a polyamide;
wherein the polyamide is (i) an amorphous aliphatic polyamide,
and includes (ii) secondary amine units resulting in tertiary amide linkages.
2 . The film of claim 1 , wherein the film includes a release liner disposed on a surface of the adhesive layer opposite the barrier layer.
3 . The film of claim 1 , wherein the polyamide includes piperazine.
4 . The film of claim 1 , wherein the adhesive is a pressure sensitive adhesive.
5 . The film of claim 1 , wherein the polyamide of the barrier layer is extrudable.
6 . The film of claim 1 , wherein the polyamide of the barrier layer dissolves in a polar solvent.
7 . The film of claim 6 , wherein the polar solvent includes 1-propanol.
8 . The film of claim 6 , wherein the polar solvent includes 1-butanol.
9 . The film of claim 1 , further comprising an ink-receptive layer on a surface of the substrate opposite the primer layer.
10 . The film of claim 1 , wherein the polyamide has (iii) a glass transition temperature of at least 40° C. and at most 70° C.
11 . The film of claim 1 , wherein the film consists of the substrate, the primer layer, the barrier layer, and the adhesive layer.
12 . The film of claim 1 , wherein the barrier layer consists of a single layer of the polyamide.
13 . The film of claim 1 , wherein the barrier layer consists essentially of the polyamide.