Coating Release Properties with Polyethylene

[SandyNeck]

We are investigating coatings/treatments that can be used on heated seal bars to join thin film plastics. Seal bar tempeatures 250-350F, seal face pressure 80-120 PSI. Heat seal bar materials are C1018, AISI 304, C4140 and Brass Alloys.

Desireable coating/treatment properties are wear resistance, excellent release from polyethylene, chemical resistance to caustic washdown solutions used in the Dairy and Meat Packaging industries.

What we have tried: PolyOnd (Nickel-Teflon), Nedox SF-2, Anodize Hardlube (Teflon treated), Electroless Nickel, Hard Chrome.

Other coating we have considered: SilverStone and Ceramics. The SilverStone (Teflon) though known to have excellent release with Poly is soft and easily removed. A bearing and shaft manufacturer has confirmed that Alumina and Chromium Ceramics do not hold up well in caustic washdown environments.

We do know that high temperature Teflon tape (Dupont Teflon coated onto a fiberglass cloth exhibits excellent release characteristics. Long term this is not a satisfactory solution.

 

[Compositepro]

Long-term, the release properties of any surface will degrade, particularly in a heat seal application where there are high temperatures, pressures and abrasion. Teflon impregnated fiberglass is effective and easy to repace. Even Silverstone (Teflon) pans do not last very long and still rely on oil and grease for a lot of release.

 

[unclesyd]

We had a number of components coated with Electroless Nickel and Teflon to prevent wear and sticking of molten polymer.

http://www.halechrome.com/nickel.html

http://www.enthone.com/resources_detail.aspx?Page=uelectroless.ascx

Here is a process(QPQ) that we used quite a bit in preventing hot polymer from wearing an sticking to guid bars

http://www.trutecind.com/heat/melon.htm

http://www.burlingtoneng.com/melonite.html

Here is one process used by our reasearch group to prevent sticking. This is a fairly elaborate and expensive process as it involes very high tmeperature.

http://www.tdcoating.com/index.php