Ovenable flexible packaging structure
The present disclosure relates generally to flexible product packaging and, in particular, to flexible packaging structures for products such as food products stored and transported for later reheating or cooking. In one aspect, an ovenable flexible packaging structure includes a paper layer having a first major surface and a second major surface opposite the first major surface, the paper layer having a cutout defining a window. A printed ink layer is disposed on the first major surface of the paper layer and a varnish layer is disposed over the printed ink layer. A heat sealable polyester layer is disposed on the second major surface of the paper layer, the heat sealable polyester layer having a strip of perforations formed therein. The strip of perforations and the cutout are at least partially overlapping with each other. An adhesive layer intermediate the paper layer and the heat sealable polymer layer includes an adhesive for adhesively bonding the paper layer to the heat sealable polymer layer. In further aspects, packaging articles formed of the flexible packaging structures and methods for making the flexible packaging structures and packaging articles are provided.
1 . An ovenable flexible packaging structure comprising:
a paper layer having a first major surface and a second major surface opposite the first major surface, the paper layer having a cutout defining a window;
a printed ink layer disposed on the first major surface of the paper layer;
a varnish layer disposed over the printed ink layer;
a heat sealable polyester layer disposed on the second major surface of the paper layer, the heat sealable polyester layer having a strip of perforations formed therein, the strip of perforations and cutout at least partially overlapping with each other; and
an adhesive layer intermediate the paper layer and the heat sealable polyester layer, the adhesive layer comprising an adhesive for adhesively bonding the paper layer to the heat sealable polyester layer.
2 . The ovenable flexible packaging structure of claim 1 , wherein the strip of perforations extends in a machine direction of the packaging structure.
3 . The ovenable flexible packaging structure of claim 1 , wherein the adhesive is one or both of an ovenable adhesive and an adhesive curable with ultraviolet radiation.
4 . The ovenable flexible packaging structure of claim 1 , wherein the adhesive has a dry coating weight in the range of from 2.5 grams per square meter to 7.5 grams per square meter.
5 . The ovenable flexible packaging structure of claim 1 , wherein the heat sealable polyester layer comprises a polyethylene terephthalate (PET) based polymer material.
6 . The ovenable flexible packaging structure of claim 1 , wherein the heat sealable polyester layer is an ovenable PET material having a seal initiation temperature (SIT) in the range of 80-160 degrees C. when sealed with a sealing pressure of 40 psi and a sealing dwell time of 0.5 seconds.
7 . The ovenable flexible packaging structure of claim 1 , wherein the heat sealable polyester layer is configured to provide a seal strength in the range of from 200 g/inch to 4000 g/inch.
8 . The ovenable flexible packaging structure of claim 1 , wherein the heat sealable polyester layer has a thickness in the range of from about 12 to about 30 microns.
9 . The ovenable flexible packaging structure of claim 1 , wherein the paper layer comprises a paper having a basis weight in the range of from about 35 gram per square meter (gsm) to about 130 gsm.
10 . The ovenable flexible packaging structure of claim 1 , wherein one or both of the ink layer and the varnish layer are curable with ultraviolet radiation.
11 . The ovenable flexible packaging structure of claim 1 , wherein the varnish layer is formed of a heat-resistant varnish.
12 . The ovenable flexible packaging structure of claim 1 , wherein the adhesive layer comprises an adhesive free region aligned with the strip of perforations for preventing the adhesive from interfering with the perforations.
13 . The ovenable flexible packaging structure of claim 12 , wherein the adhesive free region extends in a machine direction of the packaging structure.
14 . A packaging article comprising the ovenable flexible packaging structure of claim 1 .
15 . The packaging article of claim 14 , wherein the packaging article is selected from the group consisting of a bag and a pouch.
16 . A method of making an ovenable flexible packaging structure, the method comprising:
providing a web comprising a paper substrate having a first major surface and a second major surface opposite the first major surface;
forming a cutout defining a window in the paper substrate;
forming a printed ink layer disposed on the first major surface of the paper layer and a varnish layer disposed over the printed ink layer;
providing a web comprising a heat sealable polyester film;
forming a strip of perforations in the heat sealable polyester film;
applying a layer of adhesive to one or both of the second major surface of the paper substrate and the heat sealable polyester film; and
forming a laminate by bringing the web of heat sealable polyester film into contact with the paper substrate, wherein the strip of perforations and the cutout are at least partially overlapping with each other.
17 . The method of claim 16 , wherein the adhesive layer comprises an adhesive free region aligned with the strip of perforations for preventing the adhesive from interfering with the perforations.
18 . The method of claim 16 , further comprising forming a packaging article.