Multilayer film having high tear strength

Abstract

The present invention relates to a multilayer film comprising a layer (a) and a layer (c), in each case based on at least one propylene copolymer in an amount of at least 15% by weight, at least one propylene polymer in an amount of at least 40% by weight, in each case based on the total weight of the layer (a)/(c), at least one multi-ply inner layer (b) based on at least one homo- and/or copolyamide comprising isophoronediamine units as a polyamide component, adhesion promoter layers (d) and (e), wherein the thickness of the multi-ply layer (b) is at least 40% of the total thickness of the multilayer film, preferably at least 45% or at least 50%.

Claims

1. A multilayer film comprising: (a) one layer (a) based on at least one propylene copolymer in an amount of at least 15% by weight, at least one propylene homopolymer in an amount of at least 40% by weight, and optionally up to 30% by weight of additives, based in each case on the total weight of the layer (a), the components always adding up to 100% by weight, (b) one multi-ply, inner layer (b) based on at least one homo- and/or copolyamide having isophoronediamine units as a polyamide component, (c) one layer (c) based on at least one propylene copolymer in an amount of at least 15% by weight, at least one propylene homopolymer in an amount of at least 40% by weight, and optionally up to 30% by weight of additives, based in each case on the total weight of the layer (c), the components always adding up to 100% by weight, and (d) one adhesion-promoter layer (d) arranged between the layer (a) and the layer (b), based on at least one modified thermoplastic olefin homo- or copolymer, (e) one adhesion-promoter layer (e) arranged between the layer (b) and the layer (c), based on at least one modified thermoplastic olefin homo- or copolymer, the thickness of the multi-ply layer (b) being at least 40% of the total thickness of the multilayer film.

2. The multilayer film of claim 1, wherein the thickness of the multi-ply layer (b) is at least 45% of the total thickness of the multilayer film.

3. The multilayer film of claim 1, wherein the layer (b) is at least three ply.

4. The multilayer film as claimed in claim 1, wherein all plies of the layer (b) are based on at least one homo- and/or copolyamide having isophoronediamine units as a polyamide component.

5. The multilayer film of claim 1, wherein the plies of the layer (b) each have, independently of one another, a thickness within the range of 2 μm to 30 μm.

6. The multilayer film of claim 3, wherein at least two plies of the multi-ply layer (b) have a different composition.

7. The multilayer film of claim 6, wherein the multi-ply layer (b) includes two outer plies and one or more plies arranged between the two outer plies; wherein the two outer plies of the multi-ply layer (b) differ in composition from the plies of the multi-ply layer (b) that are arranged between said two outer plies.

8. The multilayer film of claim 7, wherein the plies of the multi-ply layer (b) that are arranged between said two outer plies have the same composition.

9. The multilayer film of claim 3, wherein each of the plies of the multi-ply layer (b) comprises, as a polyamide component, at least one homo- and/or copolyamide having isophoronediamine units.

10. The multilayer film of claim 1, wherein the proportion of isophoronediamine units in the copolyamide is at least 1% by weight, based in each case on the total weight of the copolyamide.

11. The multilayer film of claim 1, wherein the isophoronediamine unit-comprising polyamide component of the multi-ply layer (b) has aliphatic or aromatic dicarboxylic acid units, and the copolyamide has ε-caprolactam units copolymerized with isophoronediamine units.

12. The multilayer film of claim 1, wherein, for some of the plies of the multi-ply layer (b), the polyamide component having isophoronediamine units.

13. The multilayer film of claim 7, characterized in that the two outer plies of the multi-ply layer (b) are based on a mixture of PA-6 and a copolyamide having isophoronediamine units, aromatic dicarboxylic acid units and copolymerized ε-caprolactam units.

14. The multilayer film of claim 1, wherein the multi-ply layer (b) has a layer thickness of at least 25 μm.

15. The multilayer film of claim 1, wherein the layer (a) and the layer (c) each contain, independently of one another, at least one propylene copolymer in an amount of up to 40% by weight, based in each case on the total weight of the layer (a) or the layer (c).

16. The multilayer film of claim 1, wherein the multi-ply layer (b) serves as a barrier layer.

17. The multilayer film of claim 1, wherein it is arranged symmetrically in relation to the central, multi-ply layer (b) and wherein the layer (a) and the layer (c) are each a surface layer.

18. The multilayer film of claim 1, wherein the multilayer film includes at least one adhesion-capable layer of adhesive (f) and/or at least one layer (h) based on a sealing composition.

19. An adhesive tape comprising a multilayer film of claim 1.

20. A waterproof sheeting material, preferably a bitumen-based waterproof sheeting material, against water and/or weathering effects, comprising a multilayer film of claim 1, optionally wherein the waterproof sheeting material is a protective covering for roof, as external cladding, as protective covering for buildings or parts thereof or as pipe cladding.

Description

DETERMINATION OF TEAR STRENGTH

(1) Tear strength is determined in accordance with ASTM 1970 and specified in [N].

DETERMINATION OF TEAR STRENGTH IN ACCORDANCE WITH GB/T 529 (2008)

(2) Tear strength is determined in accordance with GB/T 529 and specified in [N]. The following examples and comparative examples serve to elucidate the invention, but are not to be interpreted as limiting.

(3) All the following % data are % by weight in each case.

I. CHEMICAL CHARACTERIZATION

(4) TABLE-US-00004 Tm Density Identification Description [° C.] [g/cm.sup.3] PP Homo Propylene homopolymer 163 0.9 PP HeCo Heterophasic propylene (block) copolymer 164 0.9 (proportion of ethylene 7-9%) HV Maleic anhydride-group modified 160 0.9 polypropylene as adhesion promoter CoPA Copolyamide, formed from 212 1.13 ε-caprolactam, isophoronediamine and isophthalic acid, having a proportion of isophoronediamine of approx. 5% PA 6 Polyamide composed of ε-caprolactam 222 1.14 UV additive UV stabilizing master batch with a n.a. 0.92 sterically hindered amine derivative Batch I: Color batch containing approx. 50% by n.a. 1.14 weight of polyethylene as polymer component Batch II: Color batch containing approx. 30% by n.a. 1.98 weight of polyethylene as polymer component

II. PRODUCTION OF THE MULTILAYER FILMS

(5) The individual layers, and plies of the layer b), of the multilayer films as per comparative examples V1 to V3 and as per examples B1 to B5, as indicated in Tables 1-8, adjoin one another in the indicated sequence of the individual layers, and plies of the layer b), in each case, and were produced by blow-film coextrusion in each case. The respective layer compositions, respective layer thicknesses and respective total layer thickness can be gathered from the corresponding Tables 1 to 8. This also applies to the plies of the layer b).

III. EXAMPLES AND COMPARATIVE EXAMPLES

(6) TABLE-US-00005 TABLE 1 V1 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 20 42 125 PP HeCo 40 Batch I 40 (d) HV 75 8 PP Homo 25 (b) CoPA 50 25 PA 6 50 (e) HV 75 8 PP Homo 25 (c) PP Homo 20 42 PP HeCo 40 Batch I 40

(7) TABLE-US-00006 TABLE 2 V2 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 47.5 140 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 100 25 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 47.5 PP HeCo 20 UV additive 5 Batch II 13

(8) TABLE-US-00007 TABLE 3 V3 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 35 140 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 100 10 CoPA 100 10 CoPA 100 10 CoPA 100 10 CoPA 100 10 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 35 PP HeCo 20 UV additive 5 Batch II 13

(9) TABLE-US-00008 TABLE 4 B1 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 22.5 140 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 100 15 CoPA 100 15 CoPA 100 15 CoPA 100 15 CoPA 100 15 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 22.5 PP HeCo 20 UV additive 5 Batch II 13

(10) TABLE-US-00009 TABLE 5 B2 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 22.5 140 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 60 15 PA 6 40 CoPA 100 15 CoPA 100 15 CoPA 100 15 CoPA 60 15 PA 6 40 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 22.5 PP HeCo 20 UV additive 5 Batch II 13

(11) TABLE-US-00010 TABLE 6 B3 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 45 22.5 140 PP HeCo 37 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 60 15 PA 6 40 CoPA 100 15 CoPA 100 15 CoPA 100 15 CoPA 60 15 PA 6 40 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 45 22.5 PP HeCo 37 UV additive 5 Batch II 13

(12) TABLE-US-00011 TABLE 7 B4 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 17.5 125 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 60 14 PA 6 40 CoPA 100 14 CoPA 100 14 CoPA 100 14 CoPA 60 14 PA 6 40 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 17.5 PP HeCo 20 UV additive 5 Batch II 13

(13) TABLE-US-00012 TABLE 8 B5 Layer Total Proportion thickness thickness Layer Material [%] [μm] [μm] (a) PP Homo 62 22.5 140 PP HeCo 20 UV additive 5 Batch I 13 (d) HV 72 10 UV additive 3 PP Homo 25 (b) CoPA 100 12 CoPA 100 16 CoPA 100 19 CoPA 100 16 CoPA 100 12 (e) HV 62 10 UV additive 3 PP Homo 25 Batch I 10 (c) PP Homo 62 22.5 PP HeCo 20 UV additive 5 Batch II 13

(14) TABLE-US-00013 TABLE 9 [GB/T 529 - 2008 measurement values: mean from, in each case, 32 measurement points] Outer layer Tear strength Tear strength Total Thickness (a)/(c) as per GB/T as per ASTM thickness No. plies layer (b) [% by weight] 529 [N] 1970 [N] Film [μm] layer (b) [μm] [%] PP-Homo PP-Copo (MD) (CD) (MD) (CD) V1 125 1 25 20 20 40 20.98 22.45 160 140 V2 140 1 25 17.9 62 20 23.75 21.94 178 142 V3 140 5 50 35.7 62 20 25.29 22.96 185 189 B1 140 5 75 53.6 62 20 27.54 26.04 238 218 B2 140 5 75 53.6 62 20 27.74 26.19 240 220 B3 140 5 75 53.6 45 37 28.31 28.41 249 211 B4 125 5 70 56 62 20 27.06 26.95 220 201 B5 140 5 75 53.6 62 20 27.51 26.11 237 219

(15) From Table 9, it is possible to gather the distinctly improved tear strength, measured in each case in accordance with ASTM 1970 and in accordance with GB/T 529-2008, of the inventive multilayer films B1 to B5 compared with the tear strength of the comparative films, the tear strength achieved according to the invention being improved by at least 10% compared with the tear strength of the comparative multilayer films.

(16) In the case of identical total thickness of the multilayer films, it is advantageous when the thickness of the multi-ply layer (b) is at least 40% of the total thickness of the multilayer film (cf. Example B4 vs. Example V1; and also Examples B1-B3 and B5 vs. Examples V2 and V3).

(17) In the case of identical multi-ply layer (b), it is additionally advantageous when, in the outer layer (a) or (c), the proportion of polypropylene homopolymer does not differ so much from the proportion of polypropylene copolymer (cf. Example B3 vs. Example B2).