How to Choose the Right Pigment for Plastic Applications

In plastic manufacturing, color is not just about appearance - it directly affects product quality, consistency, and customer satisfaction.

Many manufacturers face issues like shade variation, black specks, dull finish, or fading products. In most cases, the root cause is not the polymer or machine - it is the wrong pigment selection.

Choosing the correct pigment ensures smooth processing, stable color, and long-lasting products.

Why Pigment Selection Matters in Plastics

Unlike paints or inks, plastics undergo high processing temperatures and pressure.If the pigment cannot withstand these conditions, it starts degrading during molding.

This leads to:

• Burn marks

• Color change

• Weak appearance

• Rejected production batches

Selecting the right pigment prevents production loss and improves product performance.

Key Factors to Check Before Choosing a Pigment

1. Heat Resistance

If the pigment heat stability is lower than the processing temperature, it will burn or turn brown.

Always select pigments designed specifically for high-temperature applications.

2. Dispersion Quality

A pigment must mix uniformly inside the polymer.Poor dispersion causes visible defects such as:

• Black dots

• Color streaks

• Uneven shade

• Surface roughness

Fine particle size and proper surface treatment improve dispersion and final finish.

3. Lightfastness & Weather Resistance

For outdoor plastic products, sunlight is the biggest enemy of color.

Products like:

• Water tanks

• Chairs & furniture

• Pipes

• Automotive components

require UV-stable pigments to prevent fading and chalking.

4. Opacity & Tinting Strength

Higher tinting strength means less pigment is required to achieve the same shade.

Benefits:

• Lower production cost

• Better color consistency

• Improved batch repeatability

Cheap pigments often require higher dosage, increasing overall cost.

5. Migration & Bleeding Resistance

In some plastics, pigment particles can migrate to the surface over time.

This causes:

• Sticky surface

• Color transfer

• Packaging contamination

High-quality pigments prevent bleeding and maintain product integrity.

Common Mistakes Manufacturers Make

Many processors select pigments based only on price.

This results in:

• Machine downtime

• Rejected batches

• Customer complaints

• Higher long-term cost

Pigment should always be selected based on application compatibility, not just initial price.

Quick Pigment Selection Guide

Application	Required Pigment Property
Indoor household items	Good dispersion
Outdoor furniture	UV resistance
Pipes & tanks	Weather stability
Automotive parts	Heat resistance
Packaging	Non-migration

The right pigment improves not just color — but overall product reliability.

Correct selection helps achieve:

• Stable shade

• Smooth processing

• Lower rejection rate

• Consistent quality

At Arka Pigments, we help manufacturers select pigments based on their polymer type, processing temperature, and application needs.