Use of a highly viscous largely amorphous polyolefin for the production of a film
View Patent ↗A one-layer or multilayer sheet having good layer adhesion and good transparency is produced using a polyolefin which contains the following monomer units: a) not more than 25% by weight of units which are derived from ethene, b) not more than 75% by weight of units which are derived from propene and c) from 5 to 100% by weight of units which are derived from an α-olefin having 4 to 20 carbon atoms, the polyolefin having the following parameters: d) a weight-average molecular weight in the range of from 70 000 to 10 000 000 g/mol, e) a polydispersity in the range of from 4 to 60, f) a melt viscosity, measured by oscillation rheometry at a shear rate of 1 Hz at 190° C., in the range of from 100 000 to 100 000 000 mPa·s, g) a needle penetration in the range of from 3 to 70·0.1 mm, h) an enthalpy of fusion in the range of from 2 to 100 J/g, i) a glass transition temperature T g in the range of from −15° C. to −80° C. and j) a final melting point of the crystalline fraction in the range of from 85 to 175° C.
1. A sheet comprising a polyolefin comprising the following monomer units:
a) not more than 25% by weight of units which are derived from ethene,
b) not more than 75% by weight of units which are derived from propene, and
c) from 5 to 100% by weight of units which are derived from an α-olefin having 4 to 20 carbon atoms,
the polyolefin having the following parameters:
d) a weight-average molecular weight in the range of from 70 000 to 10 000 000 g/mol,
e) a polydispersity in the range of from 4 to 60,
f) a melt viscosity, measured by oscillation rheometry at a shear rate of 1 Hz at 190° C., in the range of from 100 000 to 100 000 000 mPa·s,
g) a needle penetration in the range of from 3 to 70·0.1 mm,
h) an enthalpy of fusion in the range of from 2 to 100 J/g,
i) a glass transition temperature T g in the range of from −15° C. to −80° C., and
j) a final melting point of a crystalline fraction in the range of from 85 to 175° C.
2. The sheet according to claim 1 , wherein the weight-average molecular weight of the polyolefin is from 100 000 g/mol to 10 000 000 g/mol.
3. The sheet according to claim 1 , wherein the polyolefin is produced by a process comprising polymerizing α-olefin monomers in the presence of a TiCl 3 .(AlCl 3 ) n mixed catalyst, n being from 0.2 to 0.5, and a trialkylaluminum compound as a cocatalyst, with a molar ratio of mixed catalyst to cocatalyst being from 1:1 to 1:10.
4. The sheet according to claim 1 , wherein the polyolefin has an alpha value in the range of from 0.5 to 0.9.
5. The sheet according to claim 1 , wherein the polyolefin is the only polymer present within the sheet.
6. The sheet according to claim 1 , wherein the sheet consists of a blend of the following components:
I. from 0.1 to 99.9% by weight of the polyolefin, and
II. from 99.9 to 0.1% by weight of a polyolefin selected from the group consisting of ethylene polymer, isotactic propylene polymer, syndiotactic propylene polymer, isotactic poly-1-butene and syndiotactic poly-1-butene, the stated percentages being based on the sum of components I and II.
7. A multi-layer sheet comprising in at least one layer the polyolefin according to claim 1 .
8. The multi-layer sheet according to claim 7 , wherein the polyolefin is the only polymer present within the at least one layer of the multi-layer sheet.
9. The multi-layer sheet according to claim 7 , wherein the at least one layer of the multi-layer sheet consists of a blend of the following components:
I. from 0.1 to 99.9% by weight of the polyolefin, and
II. from 99.9 to 0.1% by weight of a polyolefin selected from the group consisting of ethylene polymer, isotactic propylene polymer, syndiotactic propylene polymer, isotactic poly-1-butene and syndiotactic poly-1-butene, the stated percentages being based on the sum of components I and II.
10. The sheet according to claim 1 , wherein the polyolefin comprises
a) 0.1 to 20% by weight of units which are derived from ethene,
b) 0.1 to 70% by weight of units which are derived from propene, and
c) 10 to 95% by weight of units which are derived from the α-olefin.
11. The sheet according to claim 1 , wherein the polyolefin comprises
a) 1 to 16% by weight of units which are derived from ethene,
b) 4 to 65% by weight of units which are derived from propene, and
c) 15 to 90% by weight of units which are derived from the α-olefin.
12. The sheet according to claim 1 , wherein the polydispersity of the polyolefin is from 4.2 to 40.
13. The sheet according to claim 12 , wherein the polydispersity is from 4.8 to 15.
14. The sheet according to claim 1 , wherein the enthalpy of fusion of the polyolefin is from 2 to 10 J/g.
15. The sheet according to claim 1 , wherein the enthalpy of fusion of the polyolefin is from 10 to 38 J/g.
16. A method comprising packaging a food with the sheet according to claim 1 .
17. A method comprising protecting a product in need of protecting with the sheet according to claim 1 .
18. A method comprising packaging a food with the multi-sheet according to claim 7 .
19. A method comprising protecting a product in need of protecting with the multi-sheet according to claim 7 .
20. The sheet according to claim 1 , wherein the α-olefin is 1-butene, and the polyolefin has a proportion of isotactic C 4 -triads of from 10 to 75%, based on the C 4 -triads present altogether.