Pigment migration resistance is the ability of a pigment to stay where it belongs after processing, storage and use. In plastics, poor migration resistance can show up as bleeding, blooming, contact staining or color transfer. In coatings, it can show up as bleeding into a topcoat, staining through a pale layer or shade change after solvent exposure.
For buyers, migration resistance is not a small detail. It can decide whether a plastic product stains packaging, whether a PVC part bleeds into another material, or whether a coating system fails after overcoating. Fortune Chem reviews migration together with heat resistance, solvent resistance, resin compatibility and documents when recommending pigments for plastics and coatings.
Quick answer
Choose pigments with strong migration resistance when the colored material touches another surface, contains plasticizer, faces heat, is overcoated, or is used in packaging, toys, cables, flexible PVC, consumer goods or exterior coatings. A pigment that looks correct after initial color matching can still fail later if it dissolves, moves or stains under heat, pressure, solvent or plasticizer exposure.
Migration must be tested in the final resin, plasticizer, coating binder or overcoat system. Supplier data helps create the shortlist, but application testing decides approval.
What migration looks like in real products
Migration problems are often visible only after time, heat or contact. Common failure modes include:
| Failure mode | Where it appears | What buyers may see |
|---|---|---|
| Bleeding | Flexible PVC, coatings, inks and overcoating | Color moves into another layer or pale topcoat. |
| Contact staining | Plastic parts, packaging, cables, toys and consumer goods | Colored part stains white PVC, paper, film or another plastic. |
| Blooming or surface deposit | Plastics and rubber-like systems | Colorant or additive appears on the surface after storage. |
| Solvent attack | Coatings and printing inks | Pigment dissolves or shifts when exposed to solvent or overcoat. |
| Heat-assisted migration | Plastics, coatings and laminated structures | Staining becomes worse after heat aging, curing or heat sealing. |
The risk increases when the pigment has partial solubility in the surrounding system or when plasticizers, solvents, heat and pressure help movement.
Plastics: migration is critical in PVC, packaging and contact applications
In plastics, migration resistance is especially important when the product touches another material or contains mobile components such as plasticizers. Flexible PVC is a common high-risk system, but migration checks can also matter in PE, PP, EVA, rubber-like systems, cables, toys and packaging.
| Plastic application | Migration risk | Practical test |
|---|---|---|
| Flexible PVC | Plasticizer can help color move | Contact staining against white PVC or another target material. |
| Packaging film | Printed or colored layer may contact food-side or outer packaging layers | Heat aging, blocking and regulatory document review. |
| Cables and profiles | Long storage and contact with pale surfaces | Heat aging and contact staining tests. |
| Toys and consumer goods | Color transfer, safety and customer approval risk | Rubbing, contact and compliance checks. |
| Masterbatch | Pigment dispersion and carrier compatibility affect stability | Let-down testing, molded plaques and storage tests. |
For plastic-specific selection, also read How to Choose Pigments for Plastics and Masterbatch.
Coatings: migration often means bleeding into another layer
In coatings, migration resistance is closely related to solvent resistance and overcoating behavior. A pigment can look stable in the first coating layer but bleed into a second coat if the topcoat solvent partially dissolves or mobilizes it.
| Coating situation | Migration concern | Buyer check |
|---|---|---|
| White or pale topcoat over colored base | Bleeding or staining through topcoat | Apply the real topcoat and check color after drying or baking. |
| Solvent-based coating | Pigment may be attacked by strong solvents | Check solvent resistance and overpaint resistance. |
| Powder coating | Heat can increase movement or shade shift | Test cure schedule and contact surfaces. |
| Exterior coating | UV, heat and humidity can expose weak pigment selection | Review weather resistance with migration and bleeding tests. |
| Industrial maintenance coating | Chemical exposure may affect pigment stability | Test target solvents, cleaners or chemicals. |
For coating projects, migration should be checked together with heat resistance, light fastness, chemical resistance and dispersion. See How to Choose Pigments for Coatings for the broader selection workflow.
Migration resistance vs heat resistance vs solvent resistance
These properties are connected but not identical.
| Property | Meaning | Why it matters |
|---|---|---|
| Migration resistance | Pigment resists moving into another material or layer | Prevents staining, bleeding and color transfer. |
| Heat resistance | Pigment keeps shade and strength after heat exposure | Prevents color change during extrusion, baking or heat sealing. |
| Solvent resistance | Pigment resists dissolving or bleeding in solvents | Important for coatings, inks and overcoating. |
| Light fastness | Pigment resists fading under light | Important for exterior and visible products. |
| Dispersibility | Pigment breaks down and distributes evenly | Poor dispersion can make migration and staining harder to control. |
A pigment can have good heat resistance but still fail migration in a plasticized system. It can also have good initial color strength but fail when overcoated with a strong solvent topcoat. For heat-focused selection, see Pigment Heat Resistance.
Organic and inorganic pigment considerations
Organic pigments often provide bright shades and high color strength. Many high-performance organic pigments have good migration resistance, but the property varies by chemistry and grade. Inorganic pigments are often less soluble and can provide strong opacity, heat stability and durability, but they may not offer the same bright shade range.
| Pigment family | Migration note | Buyer takeaway |
|---|---|---|
| Azo and lake pigments | Performance varies widely by chemistry | Check bleeding and solvent resistance before use in PVC or overcoating. |
| DPP, quinacridone and perylene pigments | Often considered for higher-performance red, orange and violet shades | Strong candidates when brightness and durability are both needed. |
| Phthalocyanine blue and green | Commonly used in plastics and coatings with strong fastness properties | Confirm dispersion and final system compatibility. |
| Inorganic pigments | Often strong opacity and low solubility | Useful where migration, heat stability and hiding power matter. |
Do not approve by pigment family alone. Confirm the exact C.I. pigment grade, application recommendation and test result. The broader tradeoff is covered in Organic Pigment vs Inorganic Pigment.
Fortune Chem product examples
Fortune Chem product pages list application suitability and technical values that help buyers build a first shortlist. For migration-sensitive projects, prioritize high-performance grades and test them in the final system.
| Requirement | Example grades to review | Why buyers may shortlist them |
|---|---|---|
| Durable red for plastics and coatings | Pigment Red 254, Pigment Red 122, Pigment Red 177 | High-performance red options with strong heat and light fastness data. |
| High-performance yellow | Pigment Yellow 150, Pigment Yellow 110, Pigment Yellow 180 | Useful candidates when heat stability and plastics or coating suitability matter. |
| Blue and green systems | Pigment Blue 60, Pigment Blue 15:3, Pigment Green 7 | Common color families for plastics, coatings and ink-related use. |
| Violet and shading | Pigment Violet 23, Pigment Violet 19 | Useful for strong violet shades and color correction. |
| Inorganic option | Pigment Blue 29 | Ultramarine blue option when inorganic pigment behavior fits the application. |
These examples are starting points. A migration-sensitive project should always include contact staining, overcoating or storage tests before bulk order.
How to test migration resistance
Use tests that match the real failure risk. A generic color drawdown is not enough.
| Test | Best for | What to compare |
|---|---|---|
| Contact staining | Flexible PVC, plastic parts, cables and packaging | Staining on white PVC, paper, film or target material after heat and pressure. |
| Overcoating test | Coatings and painted parts | Bleeding into white or pale topcoat after drying or baking. |
| Heat aging | Plastics, coatings and laminated structures | Shade, staining and surface change after elevated temperature storage. |
| Solvent rub or solvent exposure | Coatings and inks | Color transfer, softening or bleeding under target solvent. |
| Storage stability | Masterbatch, pigment paste, coated parts | Color drift, blooming, settling or surface staining after time. |
Record the test temperature, time, contact material and evaluation scale. Without those details, migration results are hard to compare between suppliers.
Buyer checklist before approval
Before approving a pigment for a migration-sensitive application, prepare:
- resin or coating binder system;
- plasticizer, solvent, additive and stabilizer package;
- target application and contact material;
- processing or curing temperature;
- expected storage and service conditions;
- required migration, bleeding or overpaint tests;
- destination market and compliance documents;
- TDS, SDS/MSDS, COA and sample reference.
If the final product is packaging, toy, cable, consumer goods or exterior coating, share those details before sample selection. The supplier may recommend a different pigment chemistry or grade.
Practical selection workflow
Use this workflow when migration resistance matters:
- Define the final application and the material that may contact the colored surface.
- Identify the migration driver: plasticizer, solvent, heat, pressure, overcoating or long storage.
- Shortlist pigments by application suitability, heat resistance, solvent resistance and pigment family.
- Request TDS, SDS/MSDS, COA and samples.
- Run contact staining, overcoating, heat aging or solvent tests under realistic conditions.
- Compare shade, staining, bleeding, gloss and surface appearance.
- Approve the pigment only after the final resin or coating system passes testing.
Recommended next step
If you need a migration-resistant pigment recommendation, send Fortune Chem the resin or coating system, contact material, processing temperature, target shade and required documents through the contact page. The team can help shortlist grades and arrange samples for your test method.
Frequently Asked Questions
What is pigment migration resistance?
Pigment migration resistance is the ability of a pigment to resist moving into another material, coating layer or contact surface. Good migration resistance helps prevent bleeding, staining and color transfer.
Why is migration resistance important in plastics?
It is important because colored plastic can touch other materials during storage or use. Poor migration resistance can cause staining, bleeding or blooming, especially in flexible PVC, packaging, cables, toys and consumer goods.
How does pigment migration appear in coatings?
In coatings, migration often appears as bleeding into a topcoat or staining through a pale layer. Solvent-based topcoats, heat and baking can make the problem worse.
Is migration resistance the same as heat resistance?
No. Heat resistance means the pigment keeps shade and strength after heat exposure. Migration resistance means it stays in place without staining or bleeding. A pigment should be checked for both when the application requires it.
What test should I use for migration resistance?
Use the test that matches the risk: contact staining for plastics, overcoating tests for coatings, heat aging for heat-assisted migration and solvent exposure for solvent-sensitive coatings or inks.
