Desktop
Resin Data
CPVC

Cloruro de Polivinilo Clorado

CPVC·PVC·Amorphous

CPVC (Chlorinated Polyvinyl Chloride) is PVC with extra chlorine atoms added to raise its heat resistance up to 95°C —making it the #1 material for residential hot water plumbing and fire sprinkler systems. While regular PVC has 57% chlorine by weight, CPVC reaches 63-69% (typically 67%) thanks to a post-chlorination process: chlorine is bubbled over PVC in suspension until it incorporates into the chain.

The dominant global brand is Lubrizol with three families: FlowGuard Gold (residential plumbing, 12+ billion feet installed in the USA), BlazeMaster (fire sprinklers, UL/NSF listed), and Corzan (industrial — chemicals, ultrapure water). For extruded sheet, Sekisui Kydex is the reference. Top applications: hot potable water piping (NSF/ANSI 61 mandatory), sprinkler systems (LOI ≈ 60, doesn't propagate flame), and industrial corrosive chemical handling (HCl, NaOH, bleach).

In fitting injection it's heat- and shear-sensitive: drying 80°C × 2-4 h, melt 190-210°C, short residence time (max 30-90 s). Beyond that, it releases HCl, burns, and ruins equipment. Are you running CPVC? Share your experience with fittings and degradation in the comments.

The ranges shown in these data tables were compiled by the MVPS team from various parameter sheets and literature, integrating the lower and upper limits for each material type.

This information must be carefully reviewed when developing injection molding processes. Final ranges and processing tolerances are the responsibility of the engineer in charge.

These ranges are not recommended for developing specific process tolerances. MVPS always recommends requesting and consulting the supplier's data sheet.

General Properties

Chemical StructureAmorphous
Specific Gravity (Density)1.52:1
L/D Ratio22 – 25
Compression Ratio1.8 – 2
Tonnage Factor3.09 – 6.18kN/cm²
Thermal Diffusivity0.117mm²/s
Max Shear Rate20,0001/s
Shrinkage0.3 – 0.7%
Regrind❌ Not allowed
Heat Deflection (HDT) @ 1.82 MPa103°C
Glass Transition (Tg) @ 10°C/min110°C
Vicat Softening @ 50N114°C

Drying

Drying Temperature49 – 60°C
Drying Time1 – 2h
Recommended Moisture0.5%
Recommended Dryer TypeAir
Dew Point-40°C

Temperatures

Melt204 – 216°C
Nozzle182 – 188°C
Front188 – 196°C
Middle171 – 191°C
Rear171 – 179°C
Demolding38 – 60°C
Mold (Cooling)21 – 49°C
Feed Throat10 – 49°C

Processing

Back Pressure3.4 – 6.9bar
Screw Speed40 – 100RPM
Injection SpeedLow
Barrel Occupancy25 – 75%
Injection Pressure700 – 1,400Pbar
Holding Pressure175 – 1,120Pbar
Cushion3.2 – 6.4mm

Mold

Runner Diameter4.06 – 8.13mm
Gate Diameter1.02 – 2.03mm
Gate Area0.81 – 3.24mm²
Wall Thickness2.01 – 5.99mm

Venting

Depth (Vent Depth)0.0102 – 0.0305mm
Land (Vent Land)0.508 – 1.02mm
Width (Vent / Clearance)3.05 – 5.08mm
Relief (Relief Channel)0.254 – 0.381mm

Frequently asked questions

**CPVC** is PVC subjected to a **post-chlorination** process: you start with PVC suspended in water and bubble chlorine gas through until additional chlorine atoms replace hydrogens in the chain. PVC has **57% Cl**, CPVC reaches **63-69%**. The extra chlorine raises the **glass transition temperature (Tg)** from ~80°C to ~110-130°C, translating into higher continuous heat resistance and better chemical resistance.
For continuous pressure use: **93-95°C (200°F)**, vs 60°C (140°F) for PVC. Heat Deflection Temperature: **~100°C at 1.8 MPa** and **~113°C at 0.46 MPa**. Vicat softening **~115°C**. That's why it's the standard for hot potable water piping, boiler fittings, and fire sprinklers.
Three reasons: **(1) LOI ≈ 60** (Limiting Oxygen Index — highest of common plastics; doesn't propagate flame and self-extinguishes), **(2)** when exposed to fire it forms a **char layer on the surface** that insulates the inner material and maintains structural integrity for minutes long enough for the sprinkler to activate, **(3) fast installation** by solvent welding vs copper soldering. Listed systems: Lubrizol's **BlazeMaster CPVC** — UL Listed for NFPA 13 light hazard (offices, schools, hospitals, residences).
Melt: **190-210°C** (lower than many thermoplastics but higher than PVC). Mold: **40-60°C**. **Don't sustain above 210°C** —CPVC starts to decompose, releasing **gaseous HCl**, which is corrosive to equipment (screws, barrels, cavities), toxic for operators, and ruins the part. Maximum residence time **30-90 seconds**, ideally less.
**Yes**: 2-4 hours at 80°C in a desiccant dryer. Although CPVC isn't as hygroscopic as nylon or PC, surface moisture on pellets causes bubbles and silver streaks. Caution: don't exceed 90°C in the dryer —material can start degrading from the drying stage itself in prolonged tropical climates.
Excellent, better than many thermoplastics: resists **mineral acids** (HCl, dilute H₂SO₄), **strong bases** (NaOH 50%, KOH), **salts**, and **chlorinated solutions** (hypochlorite up to 15%). The large chlorine atoms **physically block** chemical attack on the chain. **Doesn't resist**: polar organic solvents (acetone, MEK, THF), aromatic hydrocarbons, esters, amines. That's why Corzan CPVC is standard in water treatment, industrial chemistry, and mineral processing.
**Yes, and it's the standard method**. The solvent cement dissolves the surface of both parts (typically THF/MEK/cyclohexanone base), joins them, and as the solvent evaporates forms a **monolithic chemical bond** —not a surface glue. Important: use **CPVC-specific cement** (not PVC cement, formulations differ), and respect cure times by diameter and ambient temperature. Threading CPVC is not recommended at high pressure: solvent weld or threaded fittings with seals only.
Typical shrinkage **0.4-0.7%**, predictable and low —it's an amorphous material with no crystalline directionality. For sanitary fittings with strict dimensional tolerances (1/2" to 4" unions), this predictability is critical. Some grades for very thin parts can drop to 0.3%.
**CPVC**: cheap, easy install with solvent weld, doesn't corrode, good heat resistance, NSF/ANSI 61 compliant. **PEX**: even faster install (crimping), flexible (fewer fittings), but more expensive and UV-sensitive (not for exposed install). **Copper**: traditional, 50+ year life, antimicrobial, but expensive and corrodes in soft or very acidic water. **2026 trend**: copper only in premium work or when local code requires; CPVC and PEX dominate new residential, CPVC remains the **lowest total cost**.
**Thermal degradation** is #1. Symptoms: part with yellow/brown stains, HCl smell (pungent, irritating), visible corrosion on screw and barrel, unexplained brittleness. Causes: exceeded temperature, long residence time, dead zone in barrel, insufficient purges. Cure: use **high-alloy steel screw and barrel (Inconel, Hastelloy)** for CPVC, conservative temperature profile, residence <90 s, **purge with HDPE or PP** when stopping production, and **never leave molten CPVC for more than 15 min without operating**.

Sources

Discussion (0)