Ask the experts! These processors and consultants have been there and done that. Post your enigma now!


UBBFriend: Email This Page to Someone!
   Plastic processing forums for extrusion information and advice and for other feed screw applications.
  Extrusion, Twin Screw
  co extrusion

Post New Topic  Post A Reply
profile | register | preferences | faq | search

next newest topic | next oldest topic
Author Topic:   co extrusion
jackie
Member

Posts: 4
From:Newcastle England
Registered: Oct 2003

posted October 07, 2003 06:45 AM     Click Here to See the Profile for jackie     Edit/Delete Message   Reply w/Quote
Can I co extrude Polystyrene with Polyethylene without a tie layer as I only have a twin screw extruder.

IP: Logged

charliehagee
Senior Member

Posts: 5
From:Scranton, PA
Registered: Sep 2003

posted October 07, 2003 09:19 AM     Click Here to See the Profile for charliehagee     Edit/Delete Message   Reply w/Quote
PS and PE will not stick together.
You need a tie layer.
If you need a co-extruder, feedblock or die, contact www.waynemachine.com

IP: Logged

jackie
Member

Posts: 4
From:Newcastle England
Registered: Oct 2003

posted October 07, 2003 10:50 AM     Click Here to See the Profile for jackie     Edit/Delete Message   Reply w/Quote
Thanks charlie but is there no additive that I could use in my main blend that would help adhesion

IP: Logged

Tom C
Moderator

Posts: 219
From:Brodheadsville, PA USA
Registered: Jun 2001

posted October 07, 2003 11:06 AM     Click Here to See the Profile for Tom C   Click Here to Email Tom C     Edit/Delete Message   Reply w/Quote
Are you trying to extrude a form or pellet?
What type of twin screw?

Tom Cunningham
Extrusion Technical Services

IP: Logged

jackie
Member

Posts: 4
From:Newcastle England
Registered: Oct 2003

posted October 07, 2003 11:27 AM     Click Here to See the Profile for jackie     Edit/Delete Message   Reply w/Quote
I am trying to extrude pellets to make a film with a base of around 400 micron ps with a 40 micron pe layer I am using an extruder with a 120MM pp screw with an LD of I think 33/1 but am unsure about the second screw but it delivers about 10% of the main one hope this is of some use.

IP: Logged

Tom C
Moderator

Posts: 219
From:Brodheadsville, PA USA
Registered: Jun 2001

posted October 07, 2003 05:35 PM     Click Here to See the Profile for Tom C   Click Here to Email Tom C     Edit/Delete Message   Reply w/Quote
Jackie,

There is a bit of terminology incompatibility here, but we can work through it.

You don't have a twin screw extruder. What you have are two single screw extruders in a co-extrusion configuration.

When you have two incompatible polymers such as PS and PE they will not stick together. Seems like a strange combination anyhow. What are you trying to make?

Tom C


IP: Logged

jackie
Member

Posts: 4
From:Newcastle England
Registered: Oct 2003

posted October 08, 2003 03:21 AM     Click Here to See the Profile for jackie     Edit/Delete Message   Reply w/Quote
Thanks for all the interest, and sorry about the confusion. I am trying to make a film with a ps base and pe layer to replace a laminated material. Base around 400 micron and pe around 40 micron.

IP: Logged

allsurplusworld
Senior Member

Posts: 7
From:
Registered: Oct 2003

posted October 10, 2003 11:45 PM     Click Here to See the Profile for allsurplusworld   Click Here to Email allsurplusworld     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by jackie:
Can I co extrude Polystyrene with Polyethylene without a tie layer as I only have a twin screw extruder.

Attn Chief Engineer

compounding plant for sale, incl. 9 extruders and polymerisation

details in www.allsurplusworld.com/abs

Register in www.allsurplusworld.com and get access to over 70.000 registered companies

Sincerely
Hans Kwist - President
AllSurplusWorld
management@allsurplusworld.com www.allsurplusworld.com

IP: Logged

All times are ET (US)

next newest topic | next oldest topic

Administrative Options: Close Topic | Archive/Move | Delete Topic
Post New Topic  Post A Reply
Hop to:

Contact Us | Feed Screw Designs

Powered by Infopop www.infopop.com © 2000
Ultimate Bulletin Board 5.45a