Quality Control Method of Light Calcium Carbonate Special for PVC

The demand for light calcium carbonate in the processing of rigid polyvinyl chloride products is very large. Whether it is PVC ~ U profile or PVC—U pipes and fittings, light calcium carbonate is an essential filler. Adding light calcium carbonate can increase the volume and reduce the cost. At the same time, it can also improve the dimensional stability, hardness and rigidity of rigid PVC products, and improve the processing performance of plastics. However, the mixed light calcium carbonate on the market has adverse effects on the performance of the product, such as poor rigidity of the product, and the grayish-blue appearance of the white product. Therefore, the choice of high-quality light calcium carbonate is very important for PVC~U product manufacturers.

The sedimentation volume, hue and apparent density of calcium carbonate can easily identify light calcium carbonate and heavy calcium carbonate, affect the degree and effect of various additives and their dispersion, and affect the processing performance and appearance color of PVC hard products.

The chemical industry standard H G/T 2226-2000 for light calcium carbonate contains relatively many testing items such as calcium carbonate content, hydrochloric acid insoluble matter, sieve residue, whiteness, water soluble matter, and iron content. Generally speaking, it is not easy to directly and conveniently apply. For light calcium carbonate, the inspection items such as sedimentation volume, hue, and apparent density are easy to operate, convenient and practical. Manufacturers of PVC hard products should focus on monitoring the production and processing conditions. At the same time, light calcium carbonate produced by different manufacturers, The sedimentation volume, apparent density, and hue indexes of the files are respectively archived as a reference for monitoring the quality of light calcium carbonate.