Differences between the Application of Small Molecular Plasticizers and Polymers in PVC

2022-12-13 11:51

PVC products can be divided into hard products and soft products, of which hard PVC is mainly used to produce plastic steel doors and windows, pipes, plates, etc., and soft PVC is mainly used in wire and cable, film, artificial leather, shoemaking and other industries. In the production process of soft PVC, plasticizers are often added to reduce the glass transition temperature of PVC, so that it has rubber elasticity at room temperature. Most of the initial plasticizers are small molecules, such as phthalate esters, aliphatic dibasic acid esters and phosphate esters. Their advantages are that they can be added in large quantities and their proportions are adjustable. Their flexibility and elasticity are obviously modified. Their disadvantages are that some phthalate plasticizers are harmful to the environment and human body. Small molecule plasticizers are also easy to move and draw out, and products are easy to lose elasticity and crack.

On January 27, 2003, the European Parliament and the Council of the European Union adopted Directive 2002/95/EC, namely the Directive on Restricting the Use of Certain Hazardous Substances in Electronic and Electrical Equipment (RoHS for short). After July 1, 2006, the EU market has officially banned the sale of products containing lead, cadmium, hexavalent chromium, mercury and other heavy metals, as well as six categories of toxic and harmful substances such as polybrominated biphenyls and polybrominated diphenyl ethers, which exceed the standard. The Regulation on the Registration, Evaluation, Licensing and Restriction System of Chemicals (REACH Regulation for short), which was formally adopted by the European Parliament and the Council on December 18, 2006, also came into force on June 1, 2007. Among them, there are nearly 100 kinds of substances with high concern, including di (2-ethylhexyl) phthalate, dibutyl phthalate Phthalate ester plasticizers such as diisobutyl phthalate and butyl benzyl phthalate.

Although small molecule plasticizers have the advantages of high plasticizing efficiency and low cost, they are volatile, not resistant to extraction, and phthalate plasticizers are harmful to human health and the environment. Polymer plasticizers, such as polyester plasticizers, liquid nitrile rubber (LNBR), powdered butadiene rubber (Elvaloy terpolymer launched by NBR DuPont), have high costs and low efficiency. However, in recent years, with the improvement of people's environmental awareness and in order to improve the long term performance of products, polymer plasticizers have attracted people's attention again.