Sheetlike composite, especially for production of dimensionally stable food or drink product containers, comprising a polymer layer P having an L value
The invention relates to a sheetlike composite comprising, as mutually superposed layers in a direction from an outer face of the sheetlike composite to an inner face of the sheetlike composite, a) a carrier layer, and b) a barrier layer; wherein the sheetlike composite additionally includes a polymer layer P comprising a first polymer; wherein the polymer layer P has an L value in the L*a*b* colour space within a range from 30 to 56. The invention further relates to methods of producing a sheetlike composite, a container precursor and a closed container and to the aforementioned method products; to a container precursor and a closed container each including at least one sheetlike region of the sheetlike composite; to uses of the sheetlike composite for production of a food or drink product container and in a microwave oven; and to uses of compositions for production of a sheetlike composite for a food or drink product container.
1. A sheetlike composite comprising, as mutually superposed layers, in a direction from an outer face of the sheetlike composite to an inner face of the sheetlike composite,
a) a carrier layer, which comprises one selected from the group consisting of cardboard, paperboard and paper, or a combination of at least two of these, and
b) a barrier layer;
wherein, between the carrier layer and the barrier layer, the sheetlike composite consists of a polymer layer P and an adhesion promoter layer;
wherein the polymer layer P includes a first polymer and has an L value in the L*a*b* colour space within a range from 30 to 56;
wherein the polymer layer P comprises a polymer composition including the first polymer, titanium oxide particles in a proportion within a range from 14% to 18% by weight, and carbon black particles in a proportion within a range from 1.1% to 2.0% by weight, wherein the percentages by weight are each based on the weight of the polymer composition; and
wherein the sheetlike composite is used for production of a food or drink product container.
2. The sheetlike composite according to claim 1 , wherein the carrier layer has a transmittance of at least 0.4% for light within a wavelength range from 475 to 480 nm.
3. The sheetlike composite according to claim 1 , wherein the carrier layer has at least one hole,
wherein the at least one hole has been covered at least by the polymer layer P as hole-covering layer.
4. The sheetlike composite according to claim 1 , wherein the barrier layer includes, as mutually superposed sublayers,
a. a barrier substrate layer, and
b. a barrier material layer;
wherein the barrier material layer has an average thickness within a range from 1 nm to 1 μm.
5. The sheetlike composite of claim 1 , wherein the polymer composition includes the carbon black particles in a proportion within a range from 1.1% to 1.8% by weight, wherein the percentages by weight are each based on the weight of the polymer composition.
6. The sheetlike composite of claim 1 , wherein the polymer composition includes the titanium oxide particles in a proportion within a range from 14% to 16% by weight, wherein the percentages by weight are each based on the weight of the polymer composition.
7. The sheetlike composite of claim 1 , wherein the polymer layer P has an average thickness within a range from 10 to 40 μm, and
wherein the carrier layer comprises cardboard with a basis weight within a range from 140 to 450 g/m 2 .
8. The sheetlike composite of claim 1 , wherein the barrier layer is an oxygen barrier layer.
9. The sheetlike composite of claim 1 , wherein the barrier layer has an oxygen permeation rate within a range from 0.1 to 40 cm 3 /(m 2 ·day·atm).