Halogen free

Hello ,
I don't know English well so I hope that you understand my meaning.

We are producing automotive wire. PVC is the material which we are using for insulation now but we want to use halogen free material for the insulation instead.

What kind of extruder do we have to use?

I also need to know information about the details of the extrusion line for halogen free insulation.

Do we have to change our extruder?

Thank you

Hello rahm,

It is a difficult to answer you because we have very little information.

(1) You are coating automotive wire now with PVC but what do your customers and your marketing department want as your new insulation, cross-linked polyethylene (XLPE)?

(2) If (1) is yes and it is XLPE, will they allow the use of the Sioplas (moisture cure) process which employs a small amount of vinyl silane?

(3) If (2) is yes, and your extruder(s) are fairly new and at least 20:1 L/D, then you will likely be able to use your existing extruder(s) although a 24:1 L/D is better in our opinion but not mandatory.

You will need a new screw and tooling as well as gravimetric mixing for the supply of the various components.
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Here are the various parts of the process to manufacture moisture cure XLPE:

Process "a" - The purchase or manufacture of a very clean LDPE or LLPE which has been compounded (pre-grafted) with vinyl silane. This first step is done in a mixing extruder and includes accurate mixing with a peroxide initiator and an antioxidant before pelletizing. We will call this compound "A".

Process "b" - The purchase or manufacture of a catalyst masterbatch produced by the accurate mixing a very clean LDPE or LLPE compounded with an organo-tin catalyst such as di-butyl tin laureate and then pelletizing. We will call this compound "B".

Process "c" - The accurate mixing of compound "A" with the catalyst masterbatch (Compound "B") and a color masterbatch by gravimetrics at a regular PE extrusion line.

Process "d" - The wire or cable insulation is then cross-linked in a steam room, in boiling water or just by leaving it in a normal plant environment for some period of time assuming of course that there is adequate moisture in the air.

We recommend you discuss this with Borealis if you wish to take this XLPE moisture cure concept further. www.borealisgroup.com/about/locations/middle-east/uae

Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641-3212

Moderators Note

I received a private message from rahm and she believes the new insulation to be polypropylene.

Please understand rahm that private messages are for personal information and such. Moreover, I am not aware of the automobile company specification you referred to as I live in Canada. Please do not use this private message system again to contact me regarding this thread. Thank you.

Generally speaking, wire and cable companies usually use a polyethylene screw for polypropylene but I would try the PVC screw before buying a new screw. All you would need then is the polypropylene and a the color masterbatch for this new polyolefin.

Make sure that your extruder and color mixer are very clean before using the polypropylene. If you are using water on the screw while extruding the PVC to prevent scorching, this practice can be discontinued with polypropylene. Your polypropylene supplier should be able to provide you with tooling drawings and the extruder thermal profile.

Check with Borealis and Dow for a start as both supply polypropylene in Europe. They should also be able to recommend the appropriate color concentrate supplier.

Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Thank you for the reply.