Plastics are indispensable in our daily lives. Household appliances, toys, transparencies, car parts, window profiles, garden furniture, cable sheaths, water and sewer pipes - plastic is omnipresent. However, until the plastic is ready for use, it goes through various stages of processing. The plastic itself - the polymer - is mixed with fillers and dyes and then brought to its final shape. For this purpose, the mass must be melted so heated. However, heat usually has a detrimental effect on the raw material. There are harmful fission products that lead to further decomposition. For example, PVC (polyvinyl chloride) develops caustic hydrochloric acid during heating, which can erode the plastic.
However, there are ways to stop this decomposition. And one of them is hydrated lime. Chemically, hydrated lime is calcium hydroxide, a fairly strong base. If you now mix this calcium hydroxide under the plastic, it absorbs the harmful acid and neutralizes it.
In addition to this direct use as an acid scavenger, there are also modified lime preparations as processing aids. The most important product for this purpose is calcium stearate, which is obtained from the chemical reaction of calcium hydroxide and stearic acid. Calcium stearate is a so-called lime soap. For example, lime soaps act as lubricants in plastics processing.
Calcium hydroxide and stearate are widely used as components of stabilizing additives for PVC. Mostly this is a combination of calcium and zinc soaps used. The market for these Ca / Zn stabilizers should continue to grow significantly as the PVC industry has undertaken to abolish the predominant lead compounds in the longer term due to their toxic heavy metal lead content.
The stabilizers unfold their effect not only during processing but also in the use of the plastic. For example, window profiles that are constantly exposed to wind and weather would be much less durable if they were not made chemically resistant.
In stabilizer mixtures only very pure and fine hydrated lime can be used. The world's leading manufacturers of PVC additives source nekablanc 0 as a raw material for their lime soaps and stabilizer formulations.
On the one hand, the grain size of the product must meet the stringent requirements and, on the other hand, the demands on purity are extremely high. In particular, this coloring impurities and dirt particles are highly undesirable. And since the plastics are often used in the food and drinking water sector, a particularly low content of heavy metals and other toxic substances is required.