Application of Hydroxypropyl MethylCellulose uses in PVC
Hydroxypropyl Methylcellulose products have the maximum consumption in the area of suspension polymerization of vinyl chloride in China. In the suspension polymerization of vinyl chloride, the dispersed system has a direct impact on the product, PVC resin, and on the quality of its processing and products. Hydroxypropyl MethylCellulose helps to improve the thermal stability of resin and control the particle size distribution(in other words, adjust PVC density), and its amount accounts for 0.025% -0.03% of PVC production. PVC resin made from high quality Hydroxypropyl MethylCellulose not only can ensure the performance line with international standards, but also can have good apparent physical properties, excellent particle properties and excellent melting rheological behavior.
In the production of synthetic resins, such as polyvinyl chloride (PVC), polyvinylidene chloride, and other copolymers, suspension polymerization is the most commonly used and must be invariant hydrophobic monomers suspended in water. As a water-soluble polymers, Hydroxypropyl MethylCellulose product has excellent surface activity and functions as protective colloidal agents. Hydroxypropyl MethylCellulose can effectively prevent polymeric particles from producing and agglomeration. Furthermore, although Hydroxypropyl MethylCellulose is a water soluble polymer, it can be slightly soluble in hydrophobic monomers and can increase the monomer porosity for the production of polymeric particles.
In addition, studies have shown that in the production process of PVC, different enterprises use different dispersed system, so the outer coating properties of PVC produced are also different, and thus Hydroxypropyl MethylCellulose can affect the processing performance of PVC resins. In the composite dispersing agent system, the suspension PVC resin prepared from the composite dispersing agent of polyvinyl alcohol (PVA) with different alcoholysis and polymerization degrees and hydroxypropyl methyl cellulose (HPMC) may have different effects on the processing performance. Tests have shown that the compound of Hydroxypropyl MethylCellulose and KP-08 or KZ-04 with the alcoholysis degree of 68% -75% is better and also advantageous for porosity of resin and the absorption of plasticizers.