DOW™ LDPE 6611 is a high viscosity low density polyethylene resin that contains various additives to assist in purging and cleaning the extruder. This polymer is formulated with agents to help it wet and scour metal surfaces within the extrusion system. It also contains a blowing agent which helps to disrupt normal flow patterns and enhance scouring action. The resin normally will foam, snap, and crackle as it leaves the die. Odors that are associated with ammonia and fish are detectable from the extrudate and feed hopper. When extruded, the resin has a grayish brown color and a very high viscosity at the die exit.

Precautions
*** Adequate ventilation is required for use. Fumes from extrusion can be irritatingto the eyes, nose, and throat. Fumes from high temperature extrusion of polyolefinresins contain various products of decomposition that may be toxic.
*** Exploding bubbles can spit hot polymer as the melt exits the die. Properprotective apparel, including eye protection, should be worn.

Other Restrictions

• DOW™ LDPE 6611 should not be extruded or exposed to temperatures above 310°C(590°F).

• DOW™ LDPE 6611 does not comply with FDA regulations, so complete purgingfrom the extrusion system is required after use.

• DOW™ LDPE 6611 contains silicon dioxide to assist in scouring hard deposits frommetal surfaces. Excessive use of this purge compound can cause prematureequipment wear, particularly in some extrusion systems that are soft nickel plated.

Applications

• DOW™ LDPE 6611 is not required for normal transitions into and out of SURLYN™ ionomer resins, NUCREL™ acid copolymer resins, and other common polyolefins. The "Disco Purge / Transition Procedure" is recommended for use during these normal transitions, and special purging compounds such as DOW™ LDPE 6611 are not part of this procedure. There are instances, however, when it is practical to use a special purging compound like DOW™ LDPE 6611. For a copy of the "Disco Purge / Transition Procedure", please contact your Dow Packaging & Industrial Polymer representative.

Examples for use include:

• Cleaning particularly dirty extruders.

• Removing die lines caused by oxidized polymer deposits.

• Purging extruders that have chronic purging problems (gels) following runs ofSURLYN™ resins, NUCREL™ resins, ELVAX™ ethylene vinyl acetate resins, orother specialty resins. Consulting your technical representative is also highlyrecommended for these cases.

• Purging prior to extrusion jobs that are particularly sensitive to gels.

• Facilitating purging for shutdowns when normal Disco Purging has not proveneffective. A shutdown is any period of time when the extruder will be completelyturned off, such as a weekend or maintenance outage. It is very important thatspecialty copolymers such as SURLYN™ and NUCREL™ be completely purgedbefore such a shutdown, as the cool-down, heat-up, and soak periods allow plentyof time to cause significant gel problems.

• Facilitating rapid removal of pigments from the extruder.

• DOW™ LDPE 6611 has also been used to facilitate pulling and cleaning largediameter extrusion screws. However, acrylic purge material is normally used forthis purpose.

• The high viscosity of DOW™ LDPE 6611 lends itself to easy cleaning of hardwareduring disassembly, because it peels rather than smearing along the metalsurfaces.

• Although most frequently used on flat die extrusion equipment, DOW™ LDPE 6611can also be used for round die converting equipment as well. It can be difficult topurge DOW™ LDPE 6611 out of standard spiral-fed blown film dies, unless a verylow melt index polyethylene is available for this purpose (0.5 MI LDPE or 1.0 MILLDPE).