Grade reference
Westlake 1230S
All grades · sourced from Westlake Corporation · checked 19 August 2026
- Producer
- Westlake Corporation
- Polymer
- PVC
- Type
- Suspension resin
- K-value
- 66
- Inherent viscosity
- 0.90 dl/g
- Producer lists it for
- Siding · Window · Fence · Door products
What that means in practice
K66, IV 0.90 — the siding, window, fence and door grade. Shares its number with 1230P but is a point higher in K and aimed at outdoor weatherable building products rather than pressure pipe.
If K-values are not something you work with daily, our PVC grades and pricing guide explains what they measure and how prime, off-spec, regrind and regranulate differ.
What to check before buying Westlake 1230S
- K65 is the most traded band, which means it is also the band where 'general-purpose PVC' gets used loosely. Get the actual grade name.
- For pipe and conduit work, ask whether the material is prime, near-prime or off-spec, and what the deviation is if it is off-spec.
- Check the packaging and storage history — suspension resin is a powder and it picks up moisture.
Buying or selling this?
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