PVC is one of the most traded polymers in the world and one of the most varied. Two loads both correctly called PVC can be entirely different materials at entirely different prices. Understanding the handful of terms that define it — K-value, rigid versus flexible, resin versus compound versus regrind — is what lets you compare offers properly and price your own material sensibly. This is a plain-English reference for anyone buying or selling PVC.
What is PVC K-value?
K-value is a measure of the molecular weight of PVC resin, derived from its viscosity in solution. In practice it tells you how the resin will process and what it suits. Common suspension resin grades cluster around K65 to K70 — a K67 suspension resin, for example, is a general-purpose grade widely used for rigid applications like pipe and profile. Lower K-values flow more easily and suit injection moulding and fittings; higher K-values give better mechanical properties and suit demanding extrusion. When PVC resin is offered, the K-value is the first thing to establish.
What is the difference between rigid and flexible PVC?
The dividing line is plasticiser. Rigid PVC (PVC-U, unplasticised) contains little or none — it is hard, strong and dimensionally stable, used for window profile, pipe, cladding and fittings. Flexible PVC is plasticised, and the amount and type of plasticiser sets how soft it is, measured as Shore hardness. Flexible PVC goes into hose, cable, flooring, membrane and moulded seals. They are not interchangeable, and a price for one tells you nothing about the other.
What is the difference between PVC resin, compound and regrind?
These describe how finished the material is:
- Resin — the base PVC polymer, usually a fine powder, defined by K-value. It is not usable alone; it must be compounded with stabilisers and additives.
- Compound — resin already blended with stabilisers, plasticisers, fillers and other additives, ready to process. Rigid or flexible, formulated for a purpose.
- Regrind — previously processed PVC (compound or product) ground for reuse. It carries a heat history and its value depends on source, cleanliness, colour and particle size.
What drives the price of PVC?
Several factors move together:
- Form and finish — resin, compound and regrind price differently; ready-to-use compound sits above raw resin, which sits above regrind for equivalent quality.
- Rigid vs flexible, and the specific formulation — a stabilised flexible compound is a different product from natural rigid regrind.
- Condition — prime, near-prime, off-spec, regrind or recycled, each a step down in price and up in the due diligence it deserves.
- The virgin resin market — recycled and off-spec PVC track it at a discount that widens when virgin is long and compresses when it is tight.
- Quantity, location and incoterm — full loads price differently from parcels, and an ex-works price is not a delivered one.
Because these move independently and change constantly, no fixed price list is reliable for long. To see what PVC is actually trading at right now — resin, compound, rigid and flexible regrind, across grades — the live board on Prime Polymers shows each seller's current asking price per tonne next to the grade, quantity and location.
How does Prime Polymers show PVC?
Every PVC listing states its type, grade, quantity, location and the seller's asking price, so you can compare resin against compound against regrind on one board. Prices are shown exactly as sellers enter them — never computed or adjusted. A free account shows every listing in full including photos and documents; membership unlocks messaging and AI-assisted matching. Prime Polymers is operated by ARC Polymers Ltd, a UK polymer trading company.
Frequently asked questions
- What does K67 mean in PVC?
- K67 refers to the K-value of the PVC resin — a measure of its molecular weight derived from solution viscosity. K67 is a common general-purpose suspension resin grade suited to rigid applications like pipe and profile. Lower K-values flow more easily; higher K-values give stronger mechanical properties.
- What is the difference between rigid and flexible PVC?
- Rigid PVC (PVC-U) is unplasticised — hard and dimensionally stable, used for window profile, pipe and fittings. Flexible PVC is plasticised, with softness set by the plasticiser and measured as Shore hardness, used for hose, cable, flooring and seals. They are different materials at different prices.
- Is PVC compound the same as PVC resin?
- No. Resin is the base polymer, a powder defined by K-value that cannot be used alone. Compound is resin already blended with stabilisers and additives, ready to process. Compound sits above raw resin in price for equivalent quality.
- What drives PVC prices?
- Form (resin, compound or regrind), rigid vs flexible, condition grade, the virgin resin market, and quantity, location and incoterm. These move independently, so PVC is best priced against live offers rather than a fixed list.
- How can I see current PVC prices?
- Check a live marketplace board. On Prime Polymers each PVC listing shows the seller's current asking price per tonne alongside the grade, quantity, location and incoterm, so you can compare what is actually on offer today rather than rely on a dated figure.