Insoluble Polyvinylpyrrolidone

Commonly used PVP level in the cosmetic industry is K-30. Commercialized PVP is white and free flowing powder or solids with its content in the mass fraction of 20%, 30%, 45% and 50% aqueous solution. PVP is soluble in water and is hygroscopic with a moisture equilibrium being 1/3 of the relative humidity of the environment. Similar as the protein hydration action, each monomer associates with 0.5mol water.

PVP is not easy to have chemical reaction. When stored at normal conditions, dry PVP is quite stable. Solution undergone mildew treatment is also stable. When heated in air to 150 °C or mixed with ammonium persulfate to heat at 90 °C for 30min, PVP will be exchanged to become a water-insoluble compound. In the presence of azo compound or a dichromate oxidizing agent, light will cause PVP solution to become gel. The co-heating of PVP solution with strong base (such as sodium silicate or trisodium phosphate) will generate precipitation. Many different compounds can generate complexes with PVP. For example, the complexes of PVP and iodine is very stable and have a good bactericidal effect and can reduce its toxicity; Adding the copolymers of the polyacrylic acid, tannic acid or methyl vinyl ether and maleic acid to the aqueous solution of PVP will generate insoluble complexes which are insoluble in water, alcohols and ketones. But when being treated with base for neutralize the poly-acid can reverse the reaction; complexation between PVP and toxins, drugs and toxic chemicals can reduce their toxicity; some kinds of dyes can also form a strong complex with PVP, which is the basis for using PVP as a dye bleaching agent.

Insoluble Polyvinylpyrrolidone has been used in a wide range of areas, for example, as a harmless functional polymer, for applications such as cosmetics, intermediates of drugs and agricultural chemicals, food additives, photosensitive electronic materials, and adhesion providing agents, or for various special industrial applications. Polyvinylpyrrolidone is usually produced by polymerizing N-vinyl-2-pyrrolidone using hydrogen peroxide as a polymerization initiator in a presence of a metal catalyst in an aqueous medium. The use of a primary, secondary, or tertiary amine as a promoter in the polymerization makes the rate of polymerization slow and brings the coloration of the resulting polymer. In contrast, the use of ammonia as a promoter in the polymerization allows the polymerization to rapidly progress and to prevent the coloration of the resulting polymer.

A solid preparation of polyvinylpyrrolidone is obtained by heat drying an aqueous solution of polyvinylpyrrolidone to sufficiently evaporate the water content of the aqueous solution. However, if ammonia is contained in an aqueous solution of polyvinylpyrrolidone, the cross-linking reaction or graft reaction of polyvinylpyrrolidone may progress in the step of heat drying, resulting in a high molecular weight polyvinylpyrrolidone which is not soluble in water. Moreover, when the resulting solid preparation of polyvinylpyrrolidone is dissolved in water, the solution may cause gelation. Therefore, there has been a demand for high-quality polyvinylpyrrolidone which caused less coloration and substantially no formation of insoluble matter and gelled matter.

The company has the GMP production lines of 600 tons annually of Povidone at low molecular weight ( Povidone K12, K15, K17, K25 and K30), 800 tons annually of Povidone at high molecular weight ( Povidone K60, K90, K120), 300 tons annually of Povidone Iodinated with high stability and 100tons annually of Chondroitine Sulfated Sodium. The company also first finished the industrial cultivation of artificial cultivating of Cordyceps and the concerned products are under marketing now. HSP will take pharmaceutical biological products or biological extracts with advantage of techniques or resources as the new development direction