Coated Paper

Overview

Coated papers have a surface coating of clay (kaolin), calcium carbonate, or other pigments applied to one or both sides. This coating fills the microscopic irregularities of the base paper, creating a smoother surface that produces sharper print reproduction, more vivid colors, and a glossy or matte finish. In the marketplace, coated board is classified under the coated_board paper type enum.

The PRD distinguishes between two coating weight categories:

• LWC (Light Weight Coated): Lighter coating weight, used for magazines, catalogs, and flyers
• HWC (Heavy Weight Coated): Heavier coating weight, used for premium packaging, book covers, and art prints

Technical Specifications

Coated Board vs Coated Paper

The PRD's paper type system includes coated_board (200-450 GSM) as a recognized type. This covers the heavier coated grades used for:

• Premium retail packaging
• Cosmetics and luxury goods boxes
• Pharmaceutical cartons
• High-end food packaging
• Retail displays and point-of-sale materials

Lighter coated papers (LWC at 40-80 GSM, for magazines and catalogs) are not explicitly enumerated in the PRD's paper type list but could be handled as products under the existing framework.

Surplus Context

Coated paper and board surplus has distinct characteristics:

• Higher value per MT: Coated grades command premium prices due to the coating process
• Surface sensitivity: Coating damage (scratches, scuffs, coating breaks) immediately reduces quality
• Moisture sensitivity: Coatings can be affected by humidity, making storage and shipping critical
• Print registration marks: Surplus from pre-printed runs may have partial print that limits reuse
• Seasonal patterns: Packaging for holidays and product launches creates seasonal overruns

Surplus sources include:

• Overruns from packaging print jobs
• Off-spec production (coating weight, gloss level, or color deviation)
• Cancelled orders (brand changes, product discontinuation)
• Trial runs for new coating formulations
• Width trims from slitting and sheeting operations

Container Compatibility

Coated board belongs to the "packaging" group in the container assembly algorithm. It can share containers with: wiki/entities/kraftliner, wiki/entities/testliner, wiki/entities/fluting, white_top_testliner, duplex, and triplex.

However, coated board is more sensitive to handling damage than uncoated packaging papers. Container loading should account for:

• Extra protection (interleaving, shrink wrap) to prevent surface damage
• Orientation to avoid pressure on coated surfaces
• Moisture control for ocean freight

Matching Behavior

In the wiki/concepts/matching-algorithm:

• coated_board is a distinct paper type (binary gate, 30% weight)
• GSM scoring follows standard tolerance bands
• Width scoring applies with machine constraints
• Additional buyer specifications may include minimum brightness and surface finish requirements (captured in BuyerSpec notes or future spec extensions)

Market Trends

The coated paper market is undergoing structural change:

• Coated printing papers (magazines, catalogs) declining due to digital media
• Coated packaging board growing due to e-commerce and premium packaging trends
• Sustainability pressure driving development of recyclable coatings (replacing traditional PE-coated grades)
• Food-contact coated board growing as regulations restrict plastic packaging

These trends affect surplus patterns: declining print grades generate more distress surplus, while growing packaging grades have less surplus relative to demand.

Relationship to Other Grades

Sources

• raw/articles/PRD -- Appendix A (Paper Types and GSM Ranges), section 5.3

Related

• wiki/entities/uncoated-woodfree -- uncoated printing/writing grade
• wiki/entities/kraftliner -- uncoated packaging linerboard
• wiki/concepts/paper-types-overview -- full paper type classification
• wiki/concepts/matching-algorithm -- paper type as binary gate
• wiki/concepts/container-assembly -- packaging group compatibility
• wiki/concepts/quality-grades -- surface damage particularly affects coated paper grades