A coolant line includes an outer layer including a polyamide molding composition and an inner layer including polypropylene and at least 0.02% by weight of a heat stabilizer. The coolant line has a high thermal aging resistance and bursting strength.
1. A coolant line comprising:
an outer layer comprising a polyamide molding composition; and
an inner layer consisting of a polypropylene molding composition;
wherein:
the polyamide molding composition comprises PA612;
the polypropylene molding composition comprises at least 50% by weight of polypropylene, at least 0.02% by weight of a heat stabilizer, and at least 0.01% by weight of a metal deactivator;
the polypropylene is a propene-ethene block copolymer including 0.5 to 20% by weight of ethene in copolymerized form;
the inner layer has a thickness of at least 0.3 mm; and
the outer layer is the outermost layer of the coolant line.
2. The coolant line as claimed in claim 1 , wherein the inner layer and the outer layer are joined by a bonding layer.
3. The coolant line as claimed in claim 1 , wherein the inner layer is adhesion-modified.
4. The coolant line as claimed in claim 1 , wherein the inner layer comprises two sublayers.
5. The coolant line as claimed in claim 1 , wherein the heat stabilizer is a sterically hindered phenol or a sulfur compound.
6. The coolant line as claimed in claim 1 , wherein the polypropylene molding composition comprises from 0.1 to 50% by weight of a nanosize filler.
7. The coolant line as claimed in claim 1 , wherein the polypropylene has a melt flow rate (MFR) in accordance with ISO 1133 (230° C./2.16 kg) in a range of from 0.1 to 3 g/10 min.
8. The coolant line as claimed in claim 1 , wherein the line is corrugated in subsections or in its entirety.
9. The coolant line as claimed in claim 8 , wherein the line is configured as a corrugated pipe having a smooth inner layer.