We process plasticized PVC compound to produce automotive part, however some days before we got problem that is so much contaminant on screen (60mesh), analysis result shows that most of such contaminant is CaCO3. We must to change screen 24h/time more than 1 week/time as last time due to contaminant is so much. This problem has never occurred before. We ask PVC compound supplier but they can't find out the reason as root cause of problem. But we prove hypothesis that fined CaCO3 (filler) they used in those LOT had problem with particle size or chemical used for cover CaCO3 (such as like stearic acid).
Does anybody give me some proper explanation?
Thank so much
Khoa
Your question is very confused. Please post a picture of your issue - what do you mean by 'automotive part'? Not sure how from a screen analysis you decide the material is CaCO3. I assume you had some other form of chemical identification? What was this form of identification? Where is this screen situated in relation to your 'item'? What does it do - other than trap material? What are these units of 24h/time and 1 week/time? Do you mean that you have to change the filters daily now instead of weekly? What is the cost per filter? May be a viable solution.
I assume that your PVC supplier uses CaCO3 as a filler or whitener? You haven't indicated a (potential) source for the CaCO3 - does it come from the supplier or your own production? CaCO3 in hydrophobic grades is often coated with stearic or oleic acids. This is not true for the other hydrophilic grades.
Dear Alan F Rawle,
Thank you for your kind concern,
We use black PVC compound (filler is stearic acid-covered Calcium Carbonate GCC). We use screen filter to avoid contaminates defecting finished product. But last LOT of PVC compound we used has many deposits on filter (that's the reason why we have to change filter more times - from weekly to daily.
Why do we assume the deposits on filter is CaCO3 ? - based on FTIR analysis (can see attached file)
Can you give me some advice
Many thanks
Khoa
If FTIR is not enough an effective method to analysis the deposit stuck on sieve
Kindly please advise
Many thanks
Khoa