# Lubricants, plasticizers and foaming agents in WPC

Canonical: https://woodplasticcomposite.net/guides/wpc-lubricants-plasticizers-foaming-agents/
Language: en
Updated: 2026-10-16
Version: 1
Review: AI-assisted English article. Human technical review has not been recorded.

## Summary

Processing aids can make a compound easier to manufacture, but an easier-flowing formulation is not necessarily a better finished product.

## Separate the additive functions

Lubricants such as selected waxes, fatty-acid derivatives and metal soaps can influence flow and interactions during processing. Dispersants target distribution of constituents. Plasticizers alter material mobility and behaviour. These functions can overlap, so the formulation needs to be evaluated as a system.

Wood/PP research examined interaction between coupling and lubrication. A separate HDPE/wood-flour investigation studied lubricant content in relation to extrusion and mechanical properties. Both support treating processing and finished-product results together. [R25,R42]

Glycerol and PEG are not universal WPC plasticizers. Likewise, the historical term dioctyl phthalate is too ambiguous for a modern procurement specification: the actual substance, intended function and suitability must be identified rather than copied from an old recipe.

https://woodplasticcomposite.net/guides/wpc-lubricants-plasticizers-foaming-agents/#separate-the-additive-functions

## Foaming changes the product being tested

Chemical blowing agents, physical foaming and expandable microspheres are routes to cellular materials. A cellular profile should be specified and tested in that form. Lower mass alone is not proof of better resource efficiency if section size, rejects or replacement frequency change.

https://woodplasticcomposite.net/guides/wpc-lubricants-plasticizers-foaming-agents/#foaming-changes-the-product-being-tested

## A production trial that reveals trade-offs

Compare output, pressure, surface quality, dimensional consistency and mechanical results. Record the dosage basis and use a stable control formulation. If reduced density is a target, report both mass per metre and the complete profile geometry.

Research and process reviews help identify candidates, but they do not authorize ingredient substitutions in a qualified commercial product.  The useful improvement is a repeatable process producing an article that still meets its declared requirements.

https://woodplasticcomposite.net/guides/wpc-lubricants-plasticizers-foaming-agents/#a-production-trial-that-reveals-trade-offs

## Evidence and source scope

[1] Experimental study; publisher abstract/excerpt.

[2] Experimental study.

[3] Research review; processing context, not additive substitution approval.

https://woodplasticcomposite.net/guides/wpc-lubricants-plasticizers-foaming-agents/#evidence-scope

## Key points



## Comparison





## Sources

1. Interaction between coupling agent and lubricants in wood–polypropylene composites — https://www.sciencedirect.com/science/article/abs/pii/S1359835X03002975
2. Effects of Lubricant Content on Extrusion Processing and Mechanical Properties of Wood Flour-High-density Polyethylene Composites — https://journals.sagepub.com/doi/10.1177/0892705710388590
3. Material Extrusion Additive Manufacturing of Wood and Lignocellulosic Filled Composites — https://www.mdpi.com/2073-4360/12/9/2115