Sheet-like composite, especially packaging laminate for dimensionally stable food-stuff containers, having a polymeric internal layer characterized by differential scanning calorimetry
The invention relates to a sheet-like composite including as layers of a layer sequence, in a direction from an external side of the sheet-like composite to an internal side of the sheet-like composite, a) a carrier layer, b) a barrier layer, and c) a polymeric internal layer, where a graph of a differential scanning calorimetry of the polymeric internal layer includes a peak A at a temperature T A and a peak B at a temperature T B , where the temperature T B is more than the temperature T A , where a width of the peak B is less by at least 3° C. than a width of the peak A. The invention further relates to a container precursor and to a closed container including the sheet-like composite, and also to a process by which the sheet-like composite is obtainable, and to a use of the sheet-like composite.
1. A laminate including as layers of a layer sequence, in a direction from an external side of the laminate to an internal side of the laminate,
a) a carrier layer which includes one selected from the group consisting of cardboard, paperboard, paper and a combination of at least two thereof,
b) a barrier layer, and
c) a polymeric internal layer,
where a graph of a differential scanning calorimetry of the polymeric internal layer includes a peak A at a temperature T A and a peak B at a temperature T B ,
where the temperature T B is more than the temperature T A ,
where a width of the peak B is less by at least 3° C. than a width of the peak A,
where the polymeric internal layer has a density in the range from 0.890 g/cm 3 to 0.980 g/cm 3 and includes as sublayers of a sublayer sequence, in a direction from a side of the polymeric internal layer that faces the barrier layer, to the inside,
a] a first internal layer which
consists to an extent of 100 wt %, based on the total weight of the first internal layer, of an HDPE, or
includes an HDPE in a fraction in a range from 45 to 90 wt %, based on the total weight of the first internal layer, and an LDPE in a fraction in a range from 10 to 55 wt %, based on the total weight of the first internal layer;
b] a second internal layer which includes an LDPE in a fraction in a range from 90 to 100 wt %, based on the total weight of the second internal layer; and
c] a third internal layer which includes an mPE in a fraction in a range from 10 to 50 wt %, based on the total weight of the third internal layer, and an LDPE in a fraction in a range from 50 to 90 wt %, based on the total weight of the third internal layer.
2. The laminate according to claim 1 , where the temperature T A is at least 80° C.
3. The laminate according to claim 1 , where the peak A is characterized by
an enthalpy of fusion H A ,
where the peak B is characterized by an enthalpy of fusion H B ,
where a ratio of the enthalpy of fusion H A to the enthalpy of fusion H B is in a range from 1:4 to 1:0.3.
4. The laminate according to claim 1 , where an absolute value of a difference between the temperature T B and the temperature T A is at least 10° C.
5. The laminate according to claim 1 , where an absolute value of a difference between the temperature T B and the temperature T A is not more than 40° C.
6. The laminate according to claim 1 , where an absolute value of a difference between an extrapolated start temperature of the peak B and an extrapolated end temperature of the peak A is in a range from 5 to 20° C.
7. A container precursor including the laminate according to claim 1 .
8. The container precursor according to claim 7 , where the laminate has at least 3 folds.
9. A process including as process steps
A) providing the laminate according to claim 1 , including a first longitudinal edge and a further longitudinal edge;
B) folding the laminate; and
C) contacting and joining the first longitudinal edge to the further longitudinal edge thereby obtaining a longitudinal seam.
10. A closed container filled with a foodstuff comprising the laminate according to claim 1 .
11. A process including as process steps
a) providing
i) a laminate precursor including as layers of a layer sequence, in a direction from an external side of the laminate precursor to an internal side of the laminate precursor,
I) a carrier layer which includes one selected from the group consisting of cardboard, paperboard, paper and a combination of at least two thereof, and
II) a barrier layer,
ii) a first polymer composition,
iii) a second polymer composition, and
iv) a third polymer composition;
b) superimposing the barrier layer, on a side of the barrier layer that is facing away from the carrier layer, in a direction from the barrier layer to the internal side, with
i) the first polymer composition, thereby obtaining a first internal layer which consists to an extent of 100 wt %, based on the total weight of the first internal layer, of an HDPE,
ii) the second polymer composition, thereby obtaining a second internal layer which includes an LDPE in a fraction in a range from 90 to 100 wt %, based on the total weight of the second internal layer, and
iii) the third polymer composition, thereby obtaining a third internal layer which includes an mPE in a fraction in a range from 10 to 50 wt %, based on the total weight of the third internal layer, and an LDPE in a fraction in a range from 50 to 90 wt %, based on the total weight of the third internal layer;
where a polymeric internal layer of the laminate has a density in the range from 0.890 g/cm 3 to 0.980 g/cm 3 and includes the first internal layer, the second internal layer and the third internal layer as sublayers,
where a graph of a differential scanning calorimetry of the polymeric internal layer includes a peak A at a temperature T A and a peak B at a temperature T B ,
where the temperature T B is more than the temperature T A ,
where a width of the peak B is less by at least 3° C. than a width of the peak A.
12. The process according to claim 11 , where the first polymer composition in process step b) is characterized by a melt flow index in a range from 2 to 14 g/10 min.
13. A process including as process steps
a) providing
i) a laminate precursor including as layers of a layer sequence, in a direction from an external side of the laminate precursor to an internal side of the laminate precursor,
I) a carrier layer which includes one selected from the group consisting of cardboard, paperboard, paper, and a combination of at least two thereof, and
II) a barrier layer,
ii) a first polymer composition,
iii) a second polymer composition, and
iv) a third polymer composition;
b) superimposing the barrier layer, on a side of the barrier layer that is facing away from the carrier layer, in a direction from the barrier layer to the internal side, with
i) the first polymer composition, thereby obtaining a first internal layer which includes an HDPE in a fraction in a range from 45 to 90 wt %, based on the total weight of the first internal layer, and an LDPE in a fraction in a range from 10 to 55 wt %, based on the total weight of the first internal layer,
ii) the second polymer composition, thereby obtaining a second internal layer which includes an LDPE in a fraction in a range from 90 to 100 wt %, based on the total weight of the second internal layer, and
iii) the third polymer composition, thereby obtaining a third internal layer which includes an mPE in a fraction in a range from 10 to 50 wt %, based on the total weight of the third internal layer, and an LDPE in a fraction in a range from 50 to 90 wt %, based on the total weight of the third internal layer;
where a polymeric internal layer of the laminate has a density in the range from 0.890 g/cm 3 to 0.980 g/cm 3 and includes the first internal layer, the second internal layer and the third internal layer as sublayers,
where a graph of a differential scanning calorimetry of the polymeric internal layer includes a peak A at a temperature T A and a peak B at a temperature T B ,
where the temperature T B is more than the temperature T A ,
where a width of the peak B is less by at least 3° C. than a width of the peak A.
14. The process according to claim 13 , where the first polymer composition in process step b) is characterized by a melt flow index in a range from 2 to 14 g/10 min.