How to increase the plasticizer absorption capacity of PVC resin powder
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Customers have reported that our DOP absorption is low; how can we increase it?
Reason 1: The type of composite dispersant is not optimized. Solution: Select a single dispersant or a composite dispersant appropriately. Purpose: To make the resin particles looser, increase the amount of plasticizer absorbed, and improve the processing and plasticization properties. Measure: Test with different dispersants. Reason 2: The concentration ratio of the composite dispersants is not optimized. Solution: Adjust the ratio of the amounts of various dispersants used. Purpose: Reduce the thickness of the film on the surface of the resin particles and achieve a more uniform shape for these particles ； Increase the porosity of the particles ； Measures to increase the amount of plasticizer absorbed: Keep the amount of hydroxypropyl (HPMC) unchanged in the original formula, and use PVA2 to replace PVA1 in equal proportions; conduct experiments with different ratios. Other reasons: 1. Unappropriate water-to-oil ratio; 2. Excessive chloride content and pH value in soft water; 3. Excessive levels of high-boiling and low-boiling monomers; 4. Inappropriate stirring speed
Simply put, it is sufficient to increase the amount of dispersant 0245 used.
Ultimately, the low DOP absorption rate is due to the low porosity of the resin particles. The reasons lie in the mixing properties of the baffle and the dispersion system; for a given production facility, the former cannot be changed. Firstly, pay attention to the quality of the monomer and pure water; ignoring the presence of high-boiling substances and acidity in the monomer can lead to many complications. Proper attention should also be given to the amount of buffer used in the reactor – an acidic environment can render cellulose ether dispersants ineffective, while an alkaline environment can render polyvinyl alcohol ineffective. Furthermore, avoiding excessively high polymerization conversion rates, using PVA with a low degree of hydrolysis, and employing special granulation agents can improve the oil absorption rate of the resin.