Method for manufacture of and a foil for enclosing or wrapping a product to be heated in an oven
A method of manufacturing a foil for enclosing or wrapping a product configured to be heated in an oven includes: providing an aluminium layer, applying a first ink material at a surface of the aluminium layer to form a first ink layer, and applying a second ink material at a surface of the first ink layer to form a second ink layer. The first ink layer is positioned between the aluminium layer and the second ink layer, and is configured to absorb radiant energy. The second ink layer is configured to allow radiant energy to pass through to reach the first ink layer. A binder system of the first ink material or the second ink material is based at least in part on polyvinyl butyral (PVB).
1. A method of manufacturing a foil for enclosing or wrapping a product configured to be heated in an oven, comprising:
providing an aluminium layer;
applying a first ink material at a surface of the aluminium layer to form a first ink layer;
applying a second ink material at a surface of the first ink layer to form a second ink laver, the first ink layer being positioned between the aluminium layer and the second ink layer, wherein the first ink layer is configured to absorb radiant energy, and the second ink layer is configured to allow the radiant energy to pass through to the first ink layer, wherein the second ink layer is an outermost ink layer of the foil, and wherein a binder system of the first ink material and the second ink material is based at least in part on polyvinyl butyral (PVB); and
applying a hardener to the second ink layer, wherein the hardener migrates from the second ink layer to the first ink layer based at least in part on the first ink layer including PVB.
2. The method according to claim 1 , wherein the first ink layer or the second ink layer is applied with a respective dry areal density or grammage of 1.5-5 grams per square meter (g/m 2 ), or a respective dry thickness of the first or the second ink layer is less than 5.9 microns (μ).
3. The method according to claim 1 , wherein flow time, measured according to International Organization for Standardization (ISO) 2431:2011, of the first or the second ink material before or during application is 35-100 seconds (s) measured with flow cup no. 3 or 30-45 (s) measured with flow cup no. 4, or the kinematic viscosity of the first or the second ink material before or during application is 10-55 square millimeter per second (mm 2 /s).
4. The method according to claim 1 , wherein the first ink material or the second ink material is diluted with ethyl acetate or propyl acetate or another acetate.
5. The method according to claim 1 , wherein the first ink material comprises carbon black.
6. The method according to claim 1 , wherein the second ink layer comprises titanium dioxide.
7. The method of claim 1 , further comprising:
providing the oven configured to transmit radiant energy,
at least partly enclosing an object with the foil, and
positioning the object within the oven.
8. The method of claim 1 , further comprising:
applying a third ink material at an opposite surface of the aluminium layer to form a third ink layer, wherein the opposite surface of the aluminium layer is opposite the surface of the aluminium layer where the first ink layer is applied; and
applying a fourth ink material at a surface of the third ink layer to form a fourth ink layer, the third ink layer positioned between the aluminium layer and the fourth ink layer, wherein the first ink layer and the third ink layer are configured to absorb radiant energy, and the second ink layer and the fourth ink layer are configured to allow the radiant energy to pass through them.