How to solve the PVC compound to penetrate the conductor?

Hi,I am engineer for automotive wire from china.I was having trouble in the extrusion process PVC plastic material can easily penetrate stranded conductor, we use a variety of methods, such as molds, extrusion problem, stranded conductors, etc., we can not solve this problem.

Thank you!

1. You can use nonwoven or similar sparator tape.
2. You can use small die to be make tight conductor to prevent  insualtion to penetrate the conductor.
3. you can change compound vicosity
4. you can degree secrew temperature at the head.