Problem overview
Calcium carbonate is the most common filler in PVC pipe. It reduces cost and adds stiffness, but higher loadings affect impact strength, fusion behaviour, shear heat and surface finish.
The right loading depends on the pipe class and standard, the filler quality (particle size, coating, moisture) and how the rest of the formulation is balanced.
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Use PVC Problem SolverCommon symptoms
- Impact test failures after increasing filler
- Higher motor ampere and machine wear
- Rough surface or reduced gloss
- Bubbles linked to filler moisture
Possible causes
| What you see | Possible causes |
|---|---|
| Lower impact strength | Higher filler loading or coarse particle size |
| Poor fusion / powder in vent | Filler absorbs lubricant and heat; processing aid may need review |
| Higher load and wear | Higher viscosity and abrasion from filler |
| Bubbles | Moisture in uncoated or poorly stored filler |
What to check
- Pipe class and standard requirements
- Filler particle size, coating and moisture
- Impact and fusion test results after any change
- Motor ampere and output
- Balance of stabilizer, lubricant and processing aid
Processing and formulation factors
Filler quality
Fine, coated, dry filler disperses better and affects properties less than coarse or moist filler.
Formulation balance
When filler increases, lubrication, processing aid and impact modification may need to be reviewed together.
Standards
Pressure pipes for drinking water typically need tighter control than non-pressure pipes. Always meet the standard your customer requires.
Practical troubleshooting checklist
- Confirm the standard and class
- Check filler quality certificate and moisture
- Increase filler in small steps only
- Repeat impact and fusion tests after each step
- Monitor ampere, surface finish and output
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Use Grade FinderWhen to contact a technical team
- You want to increase filler and keep impact strength
- Impact tests started failing after a filler change
- You need to balance cost and quality for a new pipe class
This guide gives general starting points. Results depend on your formulation, raw materials and machine; changes should be confirmed with controlled trials.
Frequently asked questions
How much calcium carbonate can be used in PVC pipe?
It depends on the pipe class, standard and filler quality. Changes should be confirmed with impact and fusion tests.
Does calcium carbonate reduce PVC pipe strength?
Higher loadings generally reduce impact strength. Filler quality and formulation balance affect how much.
Why do bubbles appear after changing filler?
New filler may carry more moisture. Check moisture and storage.
Related Friends Chemical products
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