Suspension Polyvinyl Chloride (S-PVC): Properties and Supply

Suspension Polyvinyl Chloride as an Industrial Raw Material Category

Suspension polyvinyl chloride (S-PVC) is a thermoplastic vinyl chloride polymer produced by suspension polymerisation. Unlike emulsion PVC (E-PVC), the suspension method yields larger, porous particles with an average diameter of 100 to 200 microns, providing high bulk density, good flowability and low residual monomer content. These properties make S-PVC the primary raw material for rigid and flexible articles requiring stable processing and high physico-mechanical performance. The specificity of the category is determined by the fact that S-PVC is processed by all major methods: extrusion, injection moulding, calendering, pressing and coating. However, due to low thermal stability, the polymer requires mandatory addition of heat stabilisers, lubricants and other additives. Specialised grades are produced for each method and end product, differing in K-value, bulk density, granulometry and porosity. About 80 percent of all PVC worldwide is produced by the suspension method, confirming its dominant position.

Chemical Identification and Classification of Grades

S-PVC is identified by CAS number 9002-86-2. In international trade, HS code 3904.10 is used for polyvinyl chloride in primary forms, not mixed with other components. True density of the polymer is 1.35 to 1.43 g/cm3, bulk density is in the range of 0.4 to 0.6 g/cm3. The glass transition temperature (Tg) is 75 to 85 degrees Celsius, and the processing temperature is 160 to 210 degrees Celsius. The key classification parameter for S-PVC is the K-value, which characterises molecular weight and, consequently, melt viscosity. Low molecular weight grades (K 57 to 58) have high flowability and are used for injection moulding and thin-wall articles. Medium molecular weight grades (K 66 to 68) are the basis for pipes, profiles and sheets. High molecular weight grades (K 70 to 72) are used for articles requiring increased strength and crack resistance, such as pressure pipes. In Russian practice, S-PVC grades are regulated by GOST 5960-2021, which establishes technical requirements, acceptance rules and test methods. Grades are designated, for example, PVC-S 7059M (for cable compounds, medical compounds, films and high-strength pipes) or PVC-S 6359M (for shoe compounds, profiles and sewer pipes). In international nomenclature, designations SG-3, SG-5 and SG-8 are often used, where the number corresponds to the K-value.

Regulatory Framework and Quality Standards

Circulation of S-PVC and articles made from it in Russia and the EAEU is regulated by Customs Union technical regulations, in particular TR CU 005/2011 for packaging, TR CU 007/2011 and TR CU 017/2011 for products in contact with children and skin, TR CU 021/2011 for food contact. For S-PVC itself, GOST 5960-2021 applies, which replaced earlier versions and establishes modern quality requirements. Residual vinyl chloride monomer (VCM) content in S-PVC is strictly regulated: for food and medical grades it must not exceed 1 ppm. International standards used for identification and control include ISO 1628-2 for K-value determination, ISO 60 for bulk density, ISO 4610 for particle size distribution, ASTM D1243 for viscosity, ASTM D1895 for bulk density, ASTM D1921 for particle size.

Physico-Chemical Properties and K-Value

Key physico-chemical parameters of S-PVC determine its behaviour during processing and operation. The K-value is the main parameter linking molecular weight to technological properties. The higher the K-value, the higher the molecular weight, melt viscosity, strength and crack resistance, but the lower the flowability and processability. For pipes and profiles, K 66 to 68 is considered optimal; for injection moulding, K 57 to 60; for high-strength articles, K 70 to 72. Mechanical properties of rigid PVC include tensile strength of 50 to 60 MPa, flexural strength of 80 to 100 MPa, notched impact strength of 2 to 5 kJ/m2. The material has good dielectric properties, low water absorption, light resistance and chemical resistance to acids, alkalis and salts. However, PVC has limited resistance to aromatic and chlorinated hydrocarbons, ketones and esters. When heated above 140 to 150 degrees Celsius without stabilisers, dehydrochlorination begins with the release of hydrogen chloride, requiring mandatory introduction of heat stabilisers.

Mechanism of Action and Functional Role

In processing, S-PVC acts as a thermoplastic matrix that transitions to a viscous-flow state on heating and solidifies on cooling, retaining the formed shape. However, unlike polyolefins, PVC requires a comprehensive additive system. Heat stabilisers (lead, calcium-zinc, organotin) prevent dehydrochlorination during processing and operation. Lubricants (internal and external) regulate melt viscosity and prevent sticking to equipment. Fillers (chalk, talc, glass fibre) reduce cost and increase rigidity. Plasticisers (DOP, DBP) convert rigid PVC into flexible PVC, increasing elasticity and cold resistance. The functional role of S-PVC is determined by its ability to form both rigid and flexible articles. In rigid applications (pipes, profiles, sheets), the polymer provides strength, rigidity and chemical resistance. In flexible applications (cable compounds, films, artificial leather), plasticisers impart elasticity, cold resistance and mouldability.

Processing Technology and Resin Requirements

S-PVC processing includes several stages: preparation of the compound (mixing resin with additives), processing into melt and forming. For pipe and profile extrusion, twin-screw extruders are used, providing good dispersion of additives and melt stability. For injection moulding, single-screw machines with high compression ratios are used. For sheet and film calendering, calender lines with precise temperature and gap control are used. S-PVC is subject to high requirements for particle size distribution (uniformity of particles), porosity (ability to absorb plasticisers), residual monomer content and moisture. Moisture content must not exceed 0.3 percent, since moisture causes equipment corrosion and article defects. The temperature profile of processing is usually 160 to 210 degrees Celsius depending on K-value and method.

Applications by Industry

Construction remains the largest consumer of S-PVC. In Russia, profiles account for about 48 percent of total PVC-S consumption. Window and door profiles, window sills, siding, panels, skirting boards and cable ducts are produced from rigid PVC with high performance characteristics. Pipes for water supply, sewerage and drainage are also a large segment, using grades with K 66 to 68. The cable industry uses S-PVC for cable insulation and sheaths, where dielectric properties and ageing resistance are important. Medicine uses special S-PVC grades for tubing, blood containers, gloves and single-use devices with low VCM content. Packaging uses rigid and flexible PVC for blisters, films, bottles and caps. Automotive uses PVC for interior trim, seals and cable harnesses. Consumer goods include linoleum, artificial leather, shoe compounds and toys.

Comparison with Alternative Materials

Compared to emulsion PVC (E-PVC), suspension PVC has larger particles, higher bulk density and is better suited for rigid articles. E-PVC is used for pastes, organosols and coatings. Compared to chlorinated PVC (CPVC), S-PVC has lower heat resistance but is significantly cheaper and easier to process. CPVC is used for hot water and aggressive media. Compared to polypropylene and polyethylene, PVC has higher rigidity, fire resistance and chemical resistance to certain media, but is inferior in cold resistance and processability without additives.

Common Processing Challenges

The most frequent problems in S-PVC processing are:

• Insufficient stabilisation. Without sufficient heat stabiliser, dehydrochlorination occurs, accompanied by darkening and HCl release. Precise selection of stabiliser for the temperature regime is required.
• Incorrect temperature profile. Exceeding the temperature leads to thermal degradation; insufficient temperature results in incomplete melting and defects. Strict zone control is recommended.
• Excess moisture in the resin. Moisture causes corrosion, bubbles and defects. The resin must be stored in dry conditions and checked for moisture.
• Non-uniform particle size distribution. Large particles melt more slowly, leading to uneven plasticisation and defects.
• Incompatibility of additives. Incorrect selection of lubricants and stabilisers can cause separation, migration or deterioration of properties.

Quality Control and Laboratory Methods

Quality control of S-PVC includes incoming resin analysis, document verification and laboratory testing. Key parameters: K-value (ISO 1628-2), bulk density (ISO 60), particle size distribution (ISO 4610), residual VCM content, moisture, porosity (plasticiser absorption), ash content and mechanical impurities. For finished articles, tensile strength, impact strength, Vicat softening point, dielectric properties and ageing resistance are controlled. For food and medical grades, sanitary-chemical and toxicological tests are carried out. Laboratory confirmation is especially important for S-PVC, since stabilisation defects or resin heterogeneity appear only after processing.

Storage and Transportation Conditions

S-PVC is stored in dry rooms protected from direct sunlight at temperatures not exceeding 30 degrees Celsius. The resin is moderately hygroscopic, so long-term storage requires protection from moisture. Bags and big bags must be sealed and protected from contamination. Shelf life in original packaging is usually 12 months. Transportation is carried out in 25 kg bags, 500 to 1000 kg big bags, octabins and containers. For export supplies, sea, rail and road routes are used with protection from moisture and contamination.

Analogue Selection and Interchangeability

S-PVC analogue selection is one of the key services of the portal. We help replace imported grades with comparable alternatives based on K-value, bulk density, granulometry and porosity. The algorithm includes analysis of the current grade and its technological parameters, determination of permissible deviations in key parameters, selection of options from available sources (Russia, China, other regions), verification of certificates and laboratory data, and organisation of trial batches for testing on the customer equipment. When selecting an analogue, not only K-value and bulk density but also porosity (plasticiser absorption capacity), VCM content, stabiliser type and food-contact compliance are considered. Replacement may require adjustment of the additive formulation and temperature profile.

Supply Scheme: Worldwide

The portal organises S-PVC supplies worldwide. In the Russian market, key domestic producers are Rusvinyl and BSK, as well as Sayanskhimplast and Kaustik. However, China remains the main supplier of S-PVC to Russia: its share in 2024 was 93 percent, and in the first ten months of 2025 it grew to 98 percent. Russian producers, in turn, are increasing exports. Each supply is treated as a separate project with an individual scheme covering grade selection, quality verification, logistics and customs clearance.

Logistics and Customs Clearance

S-PVC logistics includes sea, rail and road routes. For large batches of powder, container and bulk schemes are optimal. Customs clearance is supported by the portal broker: document preparation, HS code 3904.10 classification, certification and interaction with control authorities. The logistics scheme is built for the specific route and customer requirements, taking into account timing, cost and cargo safety.

FAQ

What is K-value and how does it affect processing?

K-value characterises the molecular weight and melt viscosity of PVC. The higher the K-value, the higher the strength and crack resistance, but the lower the flowability. For pipes and profiles, K 66-68 is optimal; for injection moulding, K 57-60; for high-strength articles, K 70-72.

How does S-PVC differ from E-PVC?

S-PVC is produced by the suspension method and has larger particles (100-200 microns), higher bulk density and good flowability. E-PVC is produced by the emulsion method and is used for pastes and organosols. S-PVC is more suitable for rigid articles.

Why does S-PVC require stabilisers?

PVC is thermodynamically unstable when heated above 140-150 degrees Celsius and tends to dehydrochlorinate. Stabilisers prevent this process and enable processing.

Which S-PVC grade is suitable for window profiles?

For window profiles, grades with K 66-68 and good porosity for additive absorption are usually used, such as PVC-S 6359M or analogues.

What documents accompany a supply?

Conformity certificates, quality certificates, sanitary documents for food contact, test reports, origin documents. For export batches, documents confirming compliance with the importing country requirements.

Are small batches available for testing?

Yes, trial batches from 25 kg are available for most grades. Terms are agreed individually.

Conclusion

Suspension polyvinyl chloride remains a key polymer for construction profiles, pipes, cable insulation and medical devices due to its combination of rigidity, chemical resistance and processability. A processor success depends on the correct choice of grade considering K-value, porosity and purpose, confirmed quality and stable supply. The portal helps select analogues, organise logistics and customs clearance, ensuring supply chain transparency worldwide.

Contact Us

If you are looking for S-PVC resin or need advice on grade selection, analogue search and worldwide supply organisation, please contact our team at info@apptrade.ru. We will help you find the right product, verify documentation and organise supply.