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Please refer to Material Safety Date Sheets (MSDS) for any instruction to KOCETAL® products.
Do not heat KOCETAL® resin over 250℃ or put it in a cylinder of over 230℃ for a long time (more than 30 minutes).
It may cause formaldehyde gas or discolor the resin due to the thermal decomposition.
Maintain the temperature of melt resin below 230℃.
If not used for a long period of time, purge the melt resin in cylinder and stop the operation.
If the operation is delayed, maintain the cylinder temperature around 165℃.
Make sure that resin is free from moisture absorption and contamination.
You can mix regrind with virgin KOCETAL® resin.
The mechanical properties will not change even if you use 100% of regrind resin up to five times repeatedly.
Repeated use tends to lower the elongation, but doesn’t change flow a lot.
The limit dosage of regrind resin is decided by the color.
In general, up to 30% of regrind resin is recommended for use.
Large particle of regrind can cause melting and molding problem.
Because KOCETAL®, acetal copolymer, has low water absorption, it can be used after opening.
The resin also can be used without predrying, and isn't decomposed by absorbed moisture.
However, it may cause silver streak or any appearance defects. So predrying is recommended.
In particular, you are recommended to predry and use in these cases.
Parts whose appearance is important.
Products that require accurate dimension
Mold that has mold deposit (MD)
Compounded special grade and colored grade
<Drying condition>
General case : Heated-air drying at 80℃ X 3 hours or more
If period of mold cleaning is short : Heated-air drying at 100℃ X 3 hours or more
To set the best condition for injection molding of KOCETAL®, Melt flow rate, shrinkage, dimensional stability, uniformity, and economic efficiency should be considered before manufacturing a mold.
Set the injection temperature a bit higher than 165℃, the melting temperature of KOCETAL®. Stay below 220℃ to restrain formaldehyde gas generation caused by thermal decomposition. Generally, Increase injection velocity for thin, multi-cavity mold, or dimension of product is important but, decrease injection velocity for thick product to avoid void problem. Set the cooling time to the point that the product may not deform or have plate mark when extracting it with ejector pin.
Classification | Unit | Standard grade | Reinforced grade | |
---|---|---|---|---|
Cylinder temperature | ℃ | 160 ~ 180 | 170 ~ 190 | |
℃ | 180 ~ 190 | 190 ~ 210 | ||
℃ | 190 ~ 200 | 190 ~ 210 | ||
℃ | 190 ~ 200 | 190 ~ 210 | ||
Mold temperature | ℃ | 60 ~ 80 | 70 ~ 120 | |
Injection pressure |
First pressure | ㎏/㎠ | 500 ~ 800 | 700 ~ 1,200 |
Second pressure | ㎏/㎠ | 300 ~ 500 | 1,000 | |
Back pressure | ㎏/㎠ | 10 ~ 30 | 20 ~ 50 |
Change of material
Maintain the interior of cylinder clean by using PS resin or PE resin.
In the case of molding resin that has different molding temperature, make sure to clean the cylinder.
Suspension of work
If you suspend the operation for a long time(one hour or more), purge the cylinder and set the cylinder temperature
below the melting temperature(165℃). It is recommended to purge the cylinder in case of stop.