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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: RDSpecialist on July 22, 2013, 07:58:08 AM

Title: Stereate Coated Calcium Carbonate vs. Uncoated Calcium Carbonate
Post by: RDSpecialist on July 22, 2013, 07:58:08 AM

Hello everyone!

A quick question regarding the inorgonic fillers in plastics.

During the production of polypropylene (PP) edgebands via extrusion, I saw and witness that the PP edgebands filled with stearate coated calcium carbonate have serious problems in bonding lacquer, paint and primer on the surface. In other words, the lacquer, paint etc. don't bond with the edgeband and they come off easily.. Unlike this, when I use uncoated calcium carbonate, there is no problem in lacquer, paint and primer bonding. I have some theories regarding the reduced chemical reactivity due to the presence of stereate coating, but not so sure..

Does anyone have a detailed explanation (maybe reaction-based) for this situation??

Thank you very much in advance, I will be waiting for your opinions

   

Title: Re: Stereate Coated Calcium Carbonate vs. Uncoated Calcium Carbonate
Post by: mjpam on July 26, 2013, 11:39:03 PM

Quote from: RDSpecialist on July 22, 2013, 07:58:08 AM

Hello everyone!

A quick question regarding the inorgonic fillers in plastics.

During the production of polypropylene (PP) edgebands via extrusion, I saw and witness that the PP edgebands filled with stearate coated calcium carbonate have serious problems in bonding lacquer, paint and primer on the surface. In other words, the lacquer, paint etc. don't bond with the edgeband and they come off easily.. Unlike this, when I use uncoated calcium carbonate, there is no problem in lacquer, paint and primer bonding. I have some theories regarding the reduced chemical reactivity due to the presence of stereate coating, but not so sure..

Does anyone have a detailed explanation (maybe reaction-based) for this situation??

Thank you very much in advance, I will be waiting for your opinions

 

I don't have a thorough explanation, but the stearate coating will change the way the calculcium carbonate interacts with water and other polar solvents. In particular, the stearate coating prevents water from directly contacting the calcium carbonate, so if the aqueous chemistry of calcium carbonate is essentail the adherence properties of the primer, paint, and/or lacquer, the stearate coating will interfere with it.

Title: Re: Stereate Coated Calcium Carbonate vs. Uncoated Calcium Carbonate
Post by: RDSpecialist on July 29, 2013, 01:21:57 AM

Dear mjpam,

Thank you very much for your informative reply. It gave another perspective.

Kind Regards