COMPRESSED-AIR BRAKE LINE
A compressed-air brake line which comprises: I) an external layer made of a moulding composition which comprises at least 50% by weight of PA11 and/or PA12, and II) an internal layer made of a moulding composition which comprises at least 50% by weight of polyamide whose monomer units comprise on average at least 8 C atoms is provided. Layer II) does not contain PA11 and/or PA12. The compressed-air brake line has high bursting strength even at elevated temperature, good low-temperature impact resistance, good ageing resistance, and can be produced at low cost.
1 . A compressed-air brake line, comprising:
I. an external layer having a moulding composition which comprises at least 50% by weight of PA11 and/or PA12, and
II. an internal layer having a moulding composition which comprises at least 50% by weight of a polyamide whose monomer units comprise on average at least 8 C atoms, with the proviso that PA11 and PA12 are not included.
2 . The compressed-air brake line according to claim 1 ,
further comprising:
III. an innermost layer having a moulding composition which comprises at least 50% by weight of polyamide whose monomer units comprise on average at least 8 C atoms.
3 . The compressed-air brake line according to claim 1 ,
wherein the external layer I further comprises a copper-containing stabilizer.
4 . The compressed-air brake line according to claim 3 ,
wherein the internal layer II further comprises a copper-containing stabilizer.
5 . The compressed-air brake line according to claim 2 ,
wherein the innermost layer III comprises a copper-containing stabilizer.
6 . The compressed-air brake line according to claim 3 , wherein
a copper content of the external layer I is from 0.001 to 0.05% by weight.
7 . The compressed-air brake line according to claim 4 , wherein
a copper content of the internal layer II is from 0.001 to 0.05% by weight.
8 . The compressed-air brake line according to claim 5 , wherein
a copper content of the innermost layer I is from 0.001 to 0.05% by weight.
9 . The compressed-air brake line according to claim 1 , further comprising:
an adhesion-promoter layer bonding the layers I and II to one another.
10 . The compressed-air brake line according to claim 2 , further comprising:
an adhesion-promoter layer bonding the layers II and III to one another.