PVC Production by HPMC
1. During suspension polymerization, reduce the interfacial tension between vinyl chloride monomer (VCM) and water, and help VCM to be evenly and stably dispersed in the aqueous medium.
2. Prevent the coalescence of VCM droplets at the initial stage of polymerization.
3. Prevent coalescence between polymer particles in the later stage of the polymerization process.
4. In the suspension polymerization system, it plays a dual role of dispersion and stability protection.
5. With the increase of HPMC viscosity and the decrease of hydroxypropyl content, the interfacial tension increases, the dispersion ability decreases, the glue retention ability increases, the average particle size of PVC resin increases, the resin porosity decreases, and the apparent density increases.
6. Increasing the concentration of HPMC can improve its glue retention capacity and reduce the average particle size of the resin.
Hydroxypropyl Methyl Cellulose 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 Methyl Cellulose 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 Methyl Cellulose 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.
Structural formula
(n~2)/2
OR=-OH、-OCH3、-[OCH2CH(CH3)]nOH or-[OCH2CH(CH3)]OCH3
Specification
Type | 60YT | 65YT | 75YT |
Item | HPMC | HPMC | HPMC |
Methoxy % | 28.0~30.0 | 27.0~30.0 | 19.0~24.0 |
Hydroxypropyl % | 7.0~12.0 | 4.0~7.5 | 4.0~12.0 |
Gel temperature ℃ | 58.0~64.0 | 62.0~68.0 | 70.0~90.0 |
Viscosity mPa.s | 50 | 100 | |
pH | 5.0~8.5 | ||
Loss on drying | % | ≤4.5 | |
Burning residue | % | <1.0 | |
Whiteness | % | ≥80 | |
Transmittance | % | ≥90 | |
Bulk density | g/L | 400~500 |
Applied to PVC features
1. during suspension polymerization, reduce the interfacial tension between vinyl chloride monomer (VCM) and water, and help VCM to be evenly and stably dispersed in the aqueous medium.
2. prevent the coalescence of VCM droplets at the initial stage of polymerization.
3. prevent coalescence between polymer particles in the later stage of the polymerization process.
4. in the suspension polymerization system, it plays a dual role of dispersion and stability protection.
5. with the increase of HPMC viscosity and the decrease of hydroxypropyl content, the interfacial tension increases, the dispersion ability decreases, the glue retention ability increases, the average particle size of PVC resin increases, the resin porosity decreases, and the apparent density increases.
6. increasing the concentration of HPMC can improve its glue retention capacity and reduce the average particle size of the resin.
HPMC packaging and storage
Barrel or paper plastic bag lined with polyethylene film inner bag. Net weight of each bag: 25kg.
Protect from sun and rain during storage and transportation.
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