PVC grade HPMC Hydroxypropyl Methylcellulose is a polymer variety with the most uses and the highest performance among all kinds of cellulose. It is widely used in various industrial fields and daily life. It has always been known as “industrial MSG”.
Hydroxypropyl methyl cellulose (HPMC) is one of the main dispersants in the polyvinyl chloride (PVC) industry. During the suspension polymerization of vinyl chloride, it can reduce the interfacial tension between VCM and water and help vinyl chloride monomers (VCM) is uniformly and stably dispersed in the aqueous medium; prevents VCM droplets from merging in the early stage of the polymerization process; prevents polymer particles from merging in the late stage of the polymerization process. In the suspension polymerization system, it plays a role of dispersion and protection The dual role of stability.
In the VCM suspension polymerization, the early polymerization droplets and the middle and late polymer particles are easy to coalesce at the beginning, so a dispersion protection agent must be added to the VCM suspension polymerization system. In the case of a fixed mixing method, the type, nature and amount of dispersant have become the key factors to control the characteristics of PVC particles.
Chemical Specification
|
PVC grade HPMC Specification |
HPMC 60E ( 2910 ) |
HPMC 65F ( 2906 ) | HPMC 75K ( 2208 ) |
| Gel temperature (℃) | 58-64 | 62-68 | 70-90 |
| Methoxy (WT%) | 28.0-30.0 | 27.0-30.0 | 19.0-24.0 |
| Hydroxypropoxy (WT%) | 7.0-12.0 | 4.0-7.5 | 4.0-12.0 |
| Viscosity(cps, 2% Solution) | 3, 5, 6, 15, 50, 100, 400,4000, 10000, 40000, 60000,100000,150000,200000 | ||
Product Grade:
| PVC grade HPMC | Viscosity(cps) | Remark |
| HPMC 60E50 (E50) | 40-60 | HPMC |
| HPMC 65F50 (F50) | 40-60 | HPMC |
| HPMC 75K100 (K100) | 80-120 | HPMC |
Characteristics
(1) Polymerization temperature: The polymerization temperature basically determines the average molecular weight of PVC, and the dispersant basically has no effect on the molecular weight. The gel temperature of the dispersant is higher than the polymerization temperature to ensure the dispersion of the polymer by the dispersant.
(2) Particle characteristics: particle diameter, morphology, porosity, and particle distribution are important indicators of SPVC quality, which are related to agitator/reactor design, polymerization water-to-oil ratio, dispersion system and final conversion rate of VCM, of which the dispersion system is particularly important .
(3) Stirring: Like the dispersion system, it has a great impact on the quality of SPVC. Because of the size of the VCM droplets in the water, the stirring speed increases and the droplet size decreases; when the stirring speed is too high, the droplets will aggregate and affect the final particles.
(4) Dispersion protection system: The protection system protects the VCM droplets in the early stage of the reaction to avoid merging; the generated PVC precipitates in the VCM droplets, and the dispersion system protects the agglomeration of the controlled particles, so as to obtain the final SPVC particles. The dispersion system is divided into the main dispersion system and the auxiliary dispersion system. The main dispersant has high alcoholysis degree PVA, HPMC, etc., which affect the overall performance of SPVC; auxiliary dispersing system is used to improve some characteristics of SPVC particles.
(5) The main dispersion system: They are water-soluble and stabilize the VCM droplets by reducing the interfacial tension between VCM and water. Currently in the SPVC industry, the main dispersants are PVA and HPMC. PVC grade HPMC has the advantages of low dosage, thermal stability and good plasticizing performance of SPVC. Although it is relatively expensive, it is still widely used. PVC grade HPMC is an important dispersion protection agent in PVC synthesis.
Packaging
The standard packing is 25kg/drum
20’FCL: 9 ton with palletized;10 ton unpalletized.
40’FCL: 18 ton with palletized;20 ton unpalletized.
Storage:
Store it in a cool, dry place below 30°C and protected against humidity and pressing, since the goods is thermoplastic, storage time should not exceed 36 months.
Safety notes:
The above data is in accordance with our knowledge, but don’t absolve the clients carefully checking it all immediately on receipt. To avoid the different formulation and different raw materials, please do more testing before using it.