What is ISO 1628-2 about?
ISO 1628 is a series on plastics. Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as the main ingredient. ISO 1628-2 specifies conditions for the determination of the reduced viscosity (also known as viscosity number) and K-value of PVC resins. ISO 1628-2 applies to resins in powder form which consist of homo-polymers of the monomer vinyl chloride and copolymers, terpolymers, etc., of vinyl chloride with one or more other monomers, but where vinyl chloride is the main constituent. The resins may contain lesser amounts of unpolymerized substances (e.g., emulsifying or suspending agents, catalyst residues, etc.) and other substances added during the polymerization.
Note 1: ISO 1628-2 does not apply, however, to resins having a volatile-matter content over 0,5 % ± 0,1 % when determined by ISO 1269.
Note 2: ISO 1628-2 does not apply to resins that are not entirely soluble in cyclohexanone.
Who is ISO 1628-2 for?
ISO 1628-2 on the determination of the viscosity of polymers is useful for:
- Polymer's manufacturing industries
- Polymers testing institutions
- Quality control personnel
Why should you use ISO 1628-2?
Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil-fuel based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as cotton or corn derivatives. Poly Vinyl Chloride Resin or PVC Resin as it is popularly called, is a thermoplastic resin that can be softened on reheating. A common term for this commodity polymer is Vinyl. Often available in the form of a powder, PVC granules are highly resistant to oxidization and degradation caused by the atmospheric reaction. The measurement of the viscosity of polymer solutions in organic solvents gives us a value that is related to the molecular mass of the polymer.
ISO 16282 provides the required guidance for reducing the viscosity and K-value of PVC resins. As viscosity depends on molecular mass, the higher the molecular mass higher the viscosity. Viscosity will influence flow characteristics, heat transfer, and mass transfer. For polymers, viscosity is used as a measuring stick. The molecular weight is an essential characteristic that determines some mechanical and thermal behaviours of plastics. With putting these aspects in consideration plastic products manufacturing is dependent and will affect consumer confidence and can increase the maintaining cost of plastic products so it is necessary to establish the viscosity and protect the plastic products from increasing the maintenance and cost of production cost. Using ISO 16282 you can specify conditions for the determination of the reduced viscosity (also known as viscosity number) and K-value of PVC resins.
What is changed since the last update?
BS EN ISO 1628-2:2020 supersedes ISO 1628-2:1998. BS EN ISO 1628-2:2020
includes some technical changes concerning ISO 1628-2:1998. These include:
- Normative references have been updated
- The former Table 1 has been moved to the new informative annex
