IMM 8/00

In recent months, I have noticed a white, filmy buildup when using Celcon M-90 acetal my injection molds. When I asked the supplier for a material analysis, I got no confirmable answer. Has anyone else had this experience and, if so, how did you solve the problem?

The white, filmy buildup on molds noted when using Celcon M-90 are low molecular weight acetal byproducts from the breakdown of the polymer. This is generally the result of running the material at too high a cylinder temperature, but cannot be avoided sometimes if the mold is difficult to fill completely at lower temperatures. Several competing materials claim to be more stable and may he worth sampling, including Iupital (Mitsubishi Gas), Kepital (Korea Engineering), and Ultraform (BASF).
- R. Jones, Franklin Polymers Inc., Broomall, PA, (610) 543-9432.

IMM 8/00

Adell Plastics' 2078 silicone-filled Celcon M-90 acetal will reduce friction and wear. Silicone also improved the flow characteristics.
-T.Barbera, Adell Plastics, Charlotte, NC, (704) 583-6116.

IMM 12/99

Dry the Celcon M-90 at 250F. This will bum off any volatiles that would plate out onto the mold. Also make sure that there is sufficient venting.
-B. Kuehn, GW Plastics Inc., Bethel, VT, (802) 234-9941.

We had the same problem with Celcon TX-90 acetal. Once per shift we sprayed the mold with Slide Resin Remover. This is an acceptable means of keeping the mold clean until regularly scheduled preventive maintenance.
-T. Cole, Jamestown Plastic Molders Inc., Jamestown, OH, (937) 675-6291.

Check processing conditions first. Melt temperature measured by air shot should be 360 to 390F. The mold temperature will be 170 to 250F.
-F. Lach, Ticona, Summit, NJ, (800) 833-4882.