Posts: 1
From:Pune, Mahrashtra, India
Registered: Dec 2004

posted December 08, 2004 03:11 AM               

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I am looking for formulations for manufacture of PVC pipes for use in coal mines: pressure rating 350 bar; elec. surface resistance 300 MeghOhms max.; oxygen index 25 to 29; OD 21 mm; wall thickn. 5.5 mm.

Can anybody give me a basic formulation to work upon?

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Posts: 79
From:Silver City, NM, USA
Registered: Jun 2001

posted December 16, 2004 10:51 PM               

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Here's a basic pipe formulation--blended as a dryblend mix to 120C in a high intensity mixer, and extruded into pipe on either a conical or parallel twin screw extruder.
You can use either Schedule 40 or Schedule 80
heavy walled dies or the more commonly used SDR (Standard Dimension Ratio)dies such as SDR-21 or SDR-26, all of which yield pressure rated piping.

Formulation:

PVC Homopolymer, K-65----------100 parts
Tin Mercaptoester Stabilizer-----0.5 parts
Calcium Stearate-----------------0.5 parts
165 MP Paraffin Wax--------------1.2 parts
AC 629A PE Wax-------------------0.25 parts
TiO2-----------------------------1.0 parts
CaCO3(1-2 micron)----------------3.0 parts
Acrylic Process Aid (if needed)--1.0 parts

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