CT-ART-003 Draft v2 — Pigment Selection for Color Masterbatch

1. Real Question (H1)

2. Direct Answer

Choosing the right pigment system means matching five properties of the pigment to the realities of your application and process: opacity, heat resistance, weatherability, migration risk, and regulatory requirements. Organic pigments generally give stronger, brighter colors at lower loadings but are more sensitive to heat and UV. Inorganic pigments generally withstand higher temperatures and outdoor exposure but produce less saturated colors and may need higher loadings. The best choice is not "organic or inorganic" — it is the combination that survives your processing temperature, end-use environment, polymer carrier, and compliance obligations without bleeding, fading, or failing. Before requesting samples, you should be able to state your required opacity level, peak processing temperature, expected outdoor or chemical exposure, any food-contact or toy-safety requirements, and the surface quality your customer expects.

3. Technical Explanation

3.1 What "pigment system" means in a Color Masterbatch

The definition of Color Masterbatch and its four-layer anatomy (colorant, carrier resin, dispersing aid, optional additives) is owned by CT-PILLAR-001 §3.1. This article uses that definition and focuses on the pigment layer: pigment chemistry, particle size, surface treatment, and the loading required to reach the desired color and performance. The carrier layer is a separate decision, owned by CT-ART-002.

3.2 Organic pigments vs. Inorganic pigments: a decision lens, not a rule

The organic versus inorganic distinction is useful as a starting lens, but it is not a final decision. Both families contain exceptions, and many Color Masterbatches use a blend.

Organic pigments are carbon-based colorants. They typically produce high tinting strength, bright shades, and transparent or semi-transparent effects. Their weaknesses are generally lower heat stability and lower resistance to UV, chemicals, and migration in some polymers.

Inorganic pigments are mineral or metal-based colorants. They typically withstand higher temperatures, resist UV and outdoor exposure, and are less likely to migrate. Their weaknesses are generally lower tinting strength, duller colors, and higher density, which can increase loading and cost.

Decision principle: Start with the process and end-use requirements, then choose the pigment chemistry that satisfies them. Do not choose organic or inorganic first and then try to fit it to the application.

3.3 The five selection criteria

3.3.1 Opacity

Opacity is how much the pigment hides what is underneath. A masterbatch with high opacity will cover a substrate, recycled content, or a different base color. A low-opacity masterbatch will produce translucent or transparent effects.

• High opacity is usually needed when the customer cannot see the underlying layer, when recycled content varies in color, or when the final wall thickness is thin.
• Lower opacity is acceptable when the design intentionally uses transparency, when the host polymer is already clean and consistent, or when the part is thick enough that the base color is hidden by thickness alone.

Titanium Dioxide-based White Masterbatches are the most common way to increase opacity, but this article is limited to Color Masterbatches. Within Color Masterbatches, some pigment types and particle sizes scatter more light than others. The exact opacity of a specific Allzone Color Masterbatch must be taken from its Technical Data Sheet or confirmed with a trial; products.ts does not carry opacity data, so this point is Deferred for SKU-specific claims.

3.3.2 Heat resistance

Heat resistance is the maximum temperature the pigment can tolerate without shifting color, decomposing, or losing dispersion quality. The critical temperature is not the set-point on the press; it is the peak temperature the pigment sees during melting, shearing, and residence time.

• Injection molding and extrusion of high-temperature engineering polymers can exceed 250–300 °C in localized hot spots.
• Polyolefin processing is generally lower but can still reach 200–240 °C depending on screw design, back pressure, and cycle time.
• Regrind and multiple heat histories compound the risk; a pigment that survives one pass may fail on the third or fourth. (Regrind behavior in service is owned by CT-ART-004 §4.4.)

If the brief or TDS does not list heat resistance, request it before sampling. This is especially important for heat-sensitive organic pigments.

3.3.3 Weatherability

Weatherability is the ability of the colored part to retain color and surface integrity under sunlight, moisture, temperature cycling, and atmospheric contaminants. It is not one property; it is the combined result of pigment chemistry, UV stabilizers, carrier resin, and part design.

Terminology reconciliation. "Weatherability" is the compound outcome. CT-ART-004 splits the underlying axes cleanly into Light Stability (indoor / ambient light) and UV Stability (outdoor / direct solar exposure). Use those two terms when talking to a supplier; the difference matters.

• Outdoor applications — signage, agricultural film, outdoor furniture, automotive exterior — generally need pigments with high UV and moisture resistance, often inorganic or high-performance organic grades.
• Indoor applications with no window exposure can tolerate lower weatherability.
• Weatherability claims require test data; without accelerated weathering results, any claim is Deferred. Named test frameworks and the Evidence Contract for stability data live in CT-ART-004 §6–§7.

3.3.4 Migration risk

Migration is the movement of pigment or additives out of the plastic into an adjacent material, or to the surface of the part. It appears as staining, bleeding, color transfer, or surface exudation.

Migration risk is highest when:

• The pigment has low molecular weight or poor compatibility with the host polymer.
• The part contacts solvents, oils, fats, or plasticizers.
• The application is thin film or has high surface-area-to-volume ratio.
• The polymer is soft or has low glass-transition temperature.

Organic pigments are generally more prone to migration than inorganic pigments, but this is not universal. Carrier resin and additive selection also matter; those topics are covered in CT-ART-002 and CT-ART-004.

3.3.5 Application requirements

Application requirements include mechanical, chemical, electrical, and aesthetic needs. Examples:

• A part that must be electrically insulated may need to avoid conductive pigments.
• A food-contact article must use pigments and carriers approved for that food type and temperature.
• A toy must meet migration and safety limits for saliva, sweat, and mouth contact.
• A high-gloss cosmetic packaging part may need a pigment that does not mar the surface or create streaks.

These requirements are often driven by regulation, customer specification, or end-use standard. The pigment system must be selected after those constraints are known. Regulatory depth (food contact, toys, medical) is owned by the planned Layer-4 Regulatory article; this article restricts itself to the pigment questions those regulations create.

3.4 How the five criteria interact

No single property dominates. A pigment that is perfect for heat resistance may fail on opacity. A pigment that is ideal for weatherability may fail on migration in a food-contact film. The selection process is a trade-off table, not a checklist where every box can be checked independently.

Table 1: Organic vs. Inorganic pigments as a selection lens

Note: This table describes general tendencies, not every pigment. Individual pigment grades can break these rules.

3.5 SKU grounding for Allzone Category B and M Color Masterbatches

The following statements are grounded in the canonical product catalog (src/data/products.ts). Any claim beyond the catalog is marked Deferred.

• C-Series Color Masterbatch — Pantone-matching color system. Pigment chemistry per Pantone shade: Deferred; request the TDS.
• CMB-102C / CMB-485C / CMB-286C / CMB-368C — Single-shade Color Masterbatches. Pigment chemistry, heat resistance, and regulatory approvals: Deferred to the TDS.
• Custom-Lab Color Masterbatch — Spectrometry-based custom matching. Pigment selection is part of the matching service; the buyer must still supply the five criteria.
• Bio-Color Series — Canonical matrix field: "High-Margin Functional Additives" (a taxonomy tag). Canonical carrier field: PLA / Bio-Starch Compostable Carrier. Bio-resins have lower heat resistance and different moisture sensitivity than conventional polymers; pigment selection must be verified against the specific bio-resin and processing temperature. Specific pigment data: Deferred.

4. Practical Guidance

4.1 If your product is thin film or flexible packaging, what should you check?

Thin films and flexible packaging have high surface-area-to-volume ratios and are often used for food or consumer goods. Migration, opacity, and heat resistance are usually the dominant pigment concerns.

• Opacity: If the film must hide the contents or a recycled layer, specify opacity target and measurement method.
• Migration: For food-contact film, ask which pigment approvals apply — the regulatory workflow itself is owned by the planned Layer-4 article; the pigment question is which pigment chemistry the regulation permits.
• Heat resistance: Film extrusion runs at high line speeds with narrow residence-time distribution; the pigment must survive the peak melt temperature without plate-out or color shift.

4.2 If your product is rigid packaging or household items, what should you check?

Rigid packaging includes bottles, caps, containers, and closures. These parts usually need good color consistency, reasonable opacity, and enough heat resistance for injection or blow molding.

• Opacity: Opaque bottles and caps often need a pigment system that can cover a colored base or recycled flake.
• Heat resistance: Injection molding can create hot spots; blow molding exposes the polymer to a long heat history in the parison.
• Chemical resistance: Detergents, cosmetics, oils, or food acids can extract or interact with pigments if the wrong chemistry is used.

4.3 If your product is used outdoors, what should you check?

Outdoor applications include outdoor furniture, building products, agricultural film, and automotive exterior parts. UV Stability (per CT-ART-004 terminology) dominates.

• UV Stability: Request UV and moisture resistance data. Without accelerated test data, outdoor life claims are Deferred. Test-method vocabulary and Evidence Contract live in CT-ART-004 §6–§7.
• Heat resistance: Outdoor parts often use engineering polymers or filled systems that run hot; pigment must tolerate the process peak.
• Carrier compatibility: Outdoor systems may also need UV stabilizers; the interaction between pigment, stabilizer, and carrier is covered in CT-ART-004.

4.4 If your product is a food-contact article, what should you check?

Food-contact articles are jointly constrained by the pigment, carrier, and any additives. The regulatory workflow (FDA 21 CFR, EU 10/2011, Health Canada, customer specifications, migration testing) is owned by the planned Layer-4 Regulatory article and is out of scope here. The pigment question is narrower: from the shortlist of pigments that could hit your shade, opacity, and heat class, which are approved for your food type and contact temperature? Ask the supplier for a positive list of approved pigments for the target regulation before sampling.

4.5 If your product is a toy or child-care article, what should you check?

Toys and child-care articles carry migration and heavy-metal limits set by regulation (Canada Consumer Product Safety Act / Toys Regulations; ASTM F963; EN 71 series; comparable frameworks elsewhere). The regulatory workflow — which standard applies, which tests are required — is owned by the planned Layer-4 Regulatory article. The pigment question for this article is: has the pigment system been documented against the heavy-metal and migration limits your regulation cites, and are test reports available for the specific system you are considering?

4.6 If your product is an engineering plastic part, what should you check?

Engineering plastics such as Polycarbonate, Polyamide, or Polybutylene Terephthalate are processed at higher temperatures and often require high mechanical and dimensional stability. Heat resistance becomes the gating criterion.

• Heat resistance: Verify the pigment can tolerate the peak melt temperature plus safety margin. Many standard organic pigments will fail in engineering polymers.
• Chemical resistance: Engineering parts may be exposed to oils, solvents, or cleaning agents.
• Electrical properties: Some pigments can affect insulation or tracking resistance; specify if the part has an electrical function.

4.7 If your product uses a bio-based resin, what should you check?

Bio-based resins such as Polylactic Acid or starch-based polymers have lower heat resistance and are sensitive to hydrolysis. The pigment system must be selected for these limits.

• Heat resistance: Bio-resins often process below 200 °C; the pigment must not degrade at that temperature and must not catalyze polymer degradation.
• Moisture sensitivity: Bio-resins can degrade with residual moisture; the pigment system must be compatible with the drying process.
• Compostability / biodegradability: If the article claims compostability, the pigment and any carrier additives must not block certification.

5. Market & Buying Guide

5.1 What to ask a supplier before sampling

Before requesting samples, send a brief that covers the five selection criteria. The supplier should respond with a pigment-system recommendation, not just a color match.

Key questions:

1. What is the recommended pigment chemistry for our host polymer, process temperature, and end-use environment?
2. What is the heat resistance of the pigment system in our specific polymer and process conditions?
3. Is UV / weatherability data available for the recommended system? If so, under what test standard? (Evidence-Contract format: CT-ART-004 §6.)
4. What is the migration risk in our application, and has it been tested against the relevant regulation? (Regulation itself: planned Layer-4.)
5. What is the opacity or transparency of the masterbatch at the recommended let-down ratio?
6. What regulatory documentation is available for the target end-use?
7. Does the recommendation change if we use recycled content or regrind? (Regrind behavior: CT-ART-004 §4.4.)

5.2 Red flags in a supplier response

• "Any pigment works for your polymer."
• "We will match the color and the pigment will be fine."
• "Our masterbatch is universal." — See CT-ART-002 §3 for the cluster-canonical definition of what "universal" actually means (universal across polyolefins, not across all plastics). This is a red flag whenever the host polymer is not a polyolefin.
• "Weatherability is good" without test data.
• "Food-grade" used as a blanket claim without reference to food type, temperature, and contact time.
• No heat-resistance data at your process temperature.

5.3 When to request a trial before production

A trial is necessary when:

• The process temperature is near the upper limit of the pigment's heat resistance.
• The application has strict migration or regulatory limits.
• The part will be exposed to UV, outdoor conditions, or aggressive chemicals.
• The customer requires color stability after aging, regrind, or weathering.
• The pigment system is new to your production line or host polymer.

Sample-vs-plaque and production-trial discipline is owned cluster-wide by CT-PILLAR-001 §4 Workflow A step 6 — this article does not restate it.

6. Technical/Commercial Checklist

Use this checklist before requesting a Color Masterbatch sample or sending an RFQ.

Application and end-use

• Host polymer identified and carrier compatibility verified (CT-ART-002).
• Part geometry and wall thickness known.
• Indoor or outdoor use confirmed.
• Expected service life and environment stated.
• Regulatory framework identified (planned Layer-4 owns the workflow).

Process conditions

• Molding or extrusion process identified.
• Peak melt temperature and residence time known.
• Regrind level and heat history — evaluated per CT-ART-004 §4.4.
• Shear intensity considered (high-shear processes can degrade heat-sensitive pigments).

Pigment-property questions

• Opacity target defined and measurement method stated.
• Heat resistance requirement documented.
• UV / Light Stability requirement documented per CT-ART-004 vocabulary, with test data requested.
• Migration limits and test conditions identified.
• Special requirements noted (electrical, optical, chemical, flammability).

Documentation

• Technical Data Sheet requested for the specific masterbatch.
• Safety Data Sheet requested.
• Regulatory statements or certificates requested if applicable (workflow: planned Layer-4).
• Color-matching target and tolerance method stated. Full ΔE methodology: planned Layer-3.

Supplier decision

• Supplier can explain why the pigment system was chosen.
• Supplier can provide heat, weather, and migration data on request.
• Supplier distinguishes between color match and pigment performance.

7. Documentation & Standards

Pigment-property-specific standards only. The cluster-canonical regulatory list (RoHS, REACH, EU 10/2011, FDA 21 CFR 178.3297) lives in CT-PILLAR-001 §7. Weathering / UV test standards (ISO 4892-2, ASTM G154, ASTM G155) live in CT-ART-004 §7. ΔE calculation and color-difference math belong to the planned Layer-3 article. Toy-safety and food-contact regulation belong to the planned Layer-4 article.

• ISO 787 family — General methods of test for pigments and extenders.
• ISO 105 series — Color-fastness vocabulary (as cited by CT-PILLAR-001 §7); referenced here for pigment light-fastness discipline.

If a specific pigment property (heat class, light fastness rating, migration grade) is offered to you as a data point, ask which test method and edition it comes from. A number without a method is not evidence.

8. Common Mistakes

1. Choosing color before pigment properties. A perfect color match is useless if the pigment fades, migrates, or degrades in the process. Define performance first, then match color.
2. Confusing color fastness with weatherability. Color fastness is a lab test under controlled conditions. Weatherability is real-world or accelerated outdoor performance. See CT-ART-004 for the Light Stability vs UV Stability split.
3. Assuming organic pigments are always weak or inorganic pigments are always dull. Exceptions exist in both families. Ask for the pigment grade and test data.
4. Ignoring regrind. Regrind exposes the pigment to additional heat history. Regrind stability owner: CT-ART-004 §4.4.
5. Requesting samples without a process brief. Suppliers cannot recommend a pigment system without knowing the host polymer, peak temperature, end-use, and regulatory requirements.
6. Treating carrier selection and pigment selection as one question. They are linked, but the decisions are separate. Carrier compatibility is covered in CT-ART-002.
7. Believing "food-grade" is enough. "Food-grade" must specify the food type, contact time, temperature, and migration limits. Regulatory workflow: planned Layer-4.
8. Ignoring opacity until the part is molded. Opacity is hard to fix late in development. Define it in the design stage and verify with the actual wall thickness and host polymer.

9. Related Products (secondary)

This section is intentionally secondary. Grounded strictly in src/data/products.ts. Name ≠ Spec.

• C-Series Color Masterbatch — Pantone-based color system. Pigment-property specifics per shade: Deferred to the TDS.
• CMB-102C / CMB-485C / CMB-286C / CMB-368C — Single-shade Color Masterbatches (Yellow / Red / Blue / Green). Pigment heat and migration data: Deferred to the TDS.
• Custom-Lab Color Masterbatch — Spectrometry-based custom color matching. Pigment selection is part of the matching service; the buyer must still supply the five criteria.
• Bio-Color Series — Canonical carrier: PLA / Bio-Starch Compostable Carrier. Pigment heat and moisture compatibility must be verified for the specific bio-resin.

10. Engineering Tools for This Topic

Cluster-shared calculators (Let-down Ratio, Production Consumption, Material Cost) are Planned in the roadmap and listed in CT-PILLAR-001 §10. This article does not re-list them.

Cluster-gap tools proposed here:

• Pigment Property Question Builder (Planned) — a structured checklist that turns the five criteria into an RFQ-ready brief.
• Heat-Class Checker for Color Masterbatch (Planned) — flags pigment families by process-temperature range.

Both are Planned; no route, stub, or component ships with this article.

11. Related Knowledge

• CT-PILLAR-001 — Color Masterbatch Explained: Types, Applications and Selection Principles — Foundation article. Owns definition, taxonomies, cluster-canonical regulatory list, and cluster-canonical buying-discipline rules.
• CT-ART-002 — Carrier Selection for Color Masterbatch — Engineering. Owns carrier compatibility and the canonical definition of "universal".
• CT-ART-004 — Color Stability in Color Masterbatch — Engineering. Owns the four stability axes (thermal, light, UV, polymer interaction), regrind behavior, and the Evidence Contract for stability data.
• Color Matching · ΔE Tolerances · Spectrophotometer QC (Layer 3, planned) — owns ΔE methodology and lot-acceptance QC.
• Custom Development · Food-Contact & Regulatory · Supplier Selection (Layer 4, planned) — owns the regulatory workflow deferred from §4.4 and §4.5.
• PILLAR-004 — How to Choose the Right Calcium Carbonate Grade (Frozen) — cross-cluster reference for the same trade-off method applied to a mineral filler.
• PILLAR-003 — What Is Filler Masterbatch (Frozen) — cross-cluster foundation for masterbatch-as-delivery-form.

12. Conclusion

Choosing a pigment system for a Color Masterbatch is a five-property decision: opacity, heat resistance, weatherability, migration risk, and application requirements. Organic and inorganic pigments are useful starting categories, but the final choice depends on the process and the end-use, not on the chemistry label. Before you request samples or send an RFQ, you should be able to answer: how opaque must the part be, how hot the process runs, what environment the part will see, whether it has migration or regulatory limits, and what surface or functional quality the customer expects. With those answers, a supplier can recommend a pigment system and you can verify it with data, not assumptions. The next step is to confirm that the carrier resin and the pigment system are both compatible with your host polymer — covered in CT-ART-002 — and that the combination will remain stable through production and service life — covered in CT-ART-004.

Draft v2 Self-Check

• All Blocker fixes applied (B-01 delegation; B-02 placeholder removal; B-03 title correction; B-05 tool status; B-05a Bio-Color attribution).
• Duplicates compressed with named owner (Universal → CT-ART-002 §3; Plaque discipline → Pillar §4; Regulatory list → Pillar §7; Weathering standards → CT-ART-004 §7; ΔE math → planned Layer-3; Regrind → CT-ART-004 §4.4).
• Naming Rule v2.0 preserved.
• Search Language First preserved.
• Actionable Decision preserved.
• 12 sections, fixed order.