According to the different application scope, PVC can be divided into: universal PVC resin, high polymerization degree PVC resin, cross-linked PVC resin. General purpose PVC resin is formed by polymerization of vinyl chloride monomer under the action of initiator; High polymerization degree PVC resin refers to the resin which is polymerized by adding chain growth agent in the polymerization system of vinyl chloride monomer; Crosslinked PVC resin is a resin which is polymerized by adding crosslinker containing diene and polyene into vinyl chloride monomer polymerization system.
According to the method of obtaining vinyl chloride monomer, it can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (customary ethylene method and imported monomer method are called ethylene method).
According to the polymerization method, PVC can be divided into four categories: suspension polyvinyl chloride, emulsion polyvinyl chloride, bulk polyvinyl chloride and solution polyvinyl chloride. Suspension polyvinyl chloride is the largest variety of production, accounting for about 80% of the total production of PVC. Suspension polyvinyl chloride is divided into six models according to absolute viscosity: XS-1, XS-2... XS-6; XJ-1, XJ-2... , XJ-6. The meaning of each letter in the model: X-suspension method; S-loose type; J-compact type.
According to the plasticizer content, PVC plastic is often divided into: no plasticizer PVC, plasticizer content is 0; Rigid PVC, plasticizer content is less than 10%; Semi-rigid PVC, plasticizer content is 10-30%; Soft PVC, plasticizer content is 30-70%; Polyvinyl chloride paste plastic, plasticizer content of more than 80%
Serial number | Analysis Project | Unit | Index | |
Premium product | Qualified product | |||
1 | Appearance | - | White powder | |
2 | K-Vlaue | 68-66 | 67 | |
3 | Average degree of polymerization | - | 970-1070 | |
4 | Apparent density | g/ml | 0.50-0.58 | |
5 | Volatile matter (including water content) | % | ≤0.30 | ≤0.30 |
6 | Plasticizer absorption capacity of 100g resin | g | ≥20 | |
7 | Residual VCM | μg/g | ≤3.0 | ≤5.0 |
8 | Screen residue 250un sieve hole | % | ≤2.0 | ≤8.0 |
9 | Screen residue 63un sieve hole | % | ≥95 | ≥85 |
10 | Number of fisheyes | Number/400cm² | ≤12 | ≤50 |
11 | Number of impurity particles | Number | ≤16 | ≤60 |
12 | Whiteness (160ºC, after 10min) | % | ≥78 | ≥70 |