# Masterbatch dilution in composite recipes

Canonical: https://woodplasticcomposite.net/guides/masterbatch-dilution-in-composite-recipes/
Language: en
Updated: 2026-10-15
Version: 1
Review: AI-assisted English editorial draft. Human technical review has not been recorded.

## Summary

A masterbatch dosage is not the same as the active ingredient dosage. Confusing the two can change colour, stabilisation and the polymer balance of a wood-plastic composite.

## Technical context

An illustrative 2% addition of a masterbatch containing 30% pigment contributes 0.6% pigment and 1.4% carrier to the final mixture, when all values share the same mass basis. The carrier is part of the formulation rather than an invisible ingredient.

https://woodplasticcomposite.net/guides/masterbatch-dilution-in-composite-recipes/#technical-context

## What to measure and document

Record the active concentration, carrier identity and recommended processing range. When replacing a masterbatch, compare the actual active input and carrier contribution rather than matching the old dosing percentage automatically.

https://woodplasticcomposite.net/guides/masterbatch-dilution-in-composite-recipes/#verification-plan

## Implications for development and specification

Approve the substitution through a documented trial. Inspect colour, surface quality and relevant mechanical properties after processing. A numerically equivalent pigment dose does not establish compatibility between a new carrier and the original WPC matrix.

https://woodplasticcomposite.net/guides/masterbatch-dilution-in-composite-recipes/#practical-decision

## Related reading and evidence limits

Official guidance on controlling measurement processes and supporting uncertainty statements. Use the linked work as related reading. The practical checks above are editorial recommendations, not reported test results or a substitute for product qualification.

https://woodplasticcomposite.net/guides/masterbatch-dilution-in-composite-recipes/#reading-scope

## Key points

An illustrative 2% addition of a masterbatch containing 30% pigment contributes 0.6% pigment and 1.4% carrier to the final mixture, when all values share the same mass basis.
Record the active concentration, carrier identity and recommended processing range.
Approve the substitution through a documented trial.

## Comparison

Review step | Evidence to retain
Material and geometry | Exact specimen or product identity
Verification | Method, conditions and individual observations
Decision | Approved scope and documented limitations

## What evidence is needed for masterbatch dilution in composite recipes?

Record the active concentration, carrier identity and recommended processing range. When replacing a masterbatch, compare the actual active input and carrier contribution rather than matching the old dosing percentage automatically.

## Sources

1. NIST: statistical control of measurement processes — https://www.itl.nist.gov/div898/handbook/mpc/section2/mpc2.htm