PVC material is polyvinyl chloride, which is one of the largest plastic products in the world. It is cheap and widely used. PVC resin is white or light yellow powder, which cannot be used alone and must be modified. PVC is a white powder with an amorphous structure, with a small degree of branching and poor stability to light and heat. According to different uses, different additives can be added, and PVC plastics can exhibit different physical and mechanical properties. Adding an appropriate amount of plasticizer to PVC resin can make a variety of hard, soft and transparent products.

PVC, the full name is Polyvinylchloride, is mainly composed of polyvinyl chloride, and other ingredients are added to enhance its heat resistance, toughness, ductility, etc. The top layer of this surface film is lacquer, the main component in the middle is polyvinyl chloride, and the bottom layer is a back-coated adhesive. It is a synthetic material that is deeply loved, quite popular and widely used in the world today. Its global usage ranks second among various synthetic materials. According to statistics, in 1995 alone, the production of PVC in Europe was about 5 million tons, while its consumption was 5.3 million tons. In Germany, the production and consumption of PVC averaged 1.4 million tons. PVC is being produced and applied worldwide at a growth rate of 4%. The growth rate of PVC in South East Asia is particularly significant, thanks to the urgent need for infrastructure building in countries in South East Asia. Among the materials that can produce three-dimensional surface films, PVC is the most suitable material.

PVC was first discovered in 1835 by a famous French scientist (Henri Victor Regnault). Then in 1872 another German scientist (Eugen Baumann) also discovered this new material. At that time, the pvc material was a white solid, extremely fragile, and had no practical application. In the early 20th century, a group of chemists such as Russian chemists (Ivan Ostromislensky) and Fritz Klatte tried to change the fragility of pvc and make it a commercial product, but all failed.

Until in 1926, Waldo Semon (B.F. Goodrich Company) in the United States synthesized PVC and applied for a patent in the United States. He solved the fragility of pvc by synthesizing a variety of additives, increased the expansibility of pvc material products, and made it have the basis for product commercialization. In 1931, Germany began to use the emulsion method to produce pvc, and in 1941, the United States began to use the floating method to produce pvc, so pvc material related products began to be widely used in production and life applications. With the continuous development of science and technology, the current pvc production synthesis has been replaced by the ontology synthesis method, making it more efficient and the cost is greatly reduced.

PVC modification

As mentioned above, PVC is a white powder with an amorphous structure. The glass transition temperature is 77-90 ° C, and it begins to decompose at about 170 ° C. Above 100 ° C or after prolonged sun exposure, it will decompose to produce hydrogen chloride, and further automatic Catalytic decomposition causes discoloration, and the physical and mechanical properties also decline rapidly. In practical applications, stabilizers and other auxiliaries must be added to improve the stability of heat and light. This is the so-called PVC modification. PVC products, whether injection molding or extrusion, especially PVC material products with special requirements, strictly speaking, the performance of PVC materials should belong to Customer-designed, especially designed to meet the different requirements of each user, to provide PVC solutions, that is, there are different formulations to modify.

Development History of PVC Modification

In 1933, W. L. Simon proposed to use high boiling point solvent and trimethylphenol phosphate to heat and mix with PVC, which can be processed into soft polyvinyl chloride products, which made a real breakthrough in the practicality of PVC. In 1936, the suspension polymerization of vinyl chloride and the processing application of PVC were developed. In order to simplify the production process and reduce energy consumption, the French company Saint-Gobain developed the bulk polymerization method in 1956. PVC materials with special requirements generally need to be imported from abroad. With the continuous research and development and technology accumulation of major scientific research institutes and production units in my country, the formulation design and manufacture of PVC modified Hanyong plastic new materials have reached the international advanced level. It has completely replaced imported materials from abroad, and many products have been exported abroad. Because stabilizers will be added to PVC during production, but the stabilizers are non-toxic and toxic. Only by adding toxic stabilizers such as lead salt can there be hidden dangers. However, PVC products are mixed, and some small enterprises use lead salt as stabilizers, which is difficult to meet relevant hygienic standards.

Comprehensive ban on lead in PVC material products

The prohibition of lead in PVC material products is a commonplace topic. Since lead salt is a heavy metal that is harmful to human health, since the 1980s, developed countries such as Europe, the United States and Japan have successively put forward requirements to prohibit the use of lead salt, and have successively introduced regulations to ban lead. In the 21st century, the call for a ban on lead in my country's plastics industry is growing. The former Ministry of Construction issued an announcement in 2004 that lead salt heat stabilizers were banned in PVC pipes for water supply nationwide; in 2006, my country issued the "Administrative Measures for Pollution Control of Electronic Information Products", which also included lead in electronic information products., cadmium, barium and other heavy metals are limited and banned; relevant industry organizations are also actively promoting the prohibition of lead.