Paper Coating: A Process to Create Technical Substrates
- Karine Morel
- [wpcode id="48710"]
Table of content
When coating gives paper unprecedented performance, notably in barrier properties and heat-sealability.
In the world of paper and packaging, terms such as coated paper, uncoated paper, coating, or coating formulation often appear. These technical notions describe an essential process: coating, which allows a substrate to meet market requirements, whether barrier properties or heat-sealability.
What if coating not only enhanced appearance but transformed ordinary paper into a high-value material?
1- Coating and Surface Treatment: What Does It Really Mean?
Coating consists of applying a specially formulated layer to a substrate (paper, cardboard, textile, flexible film…). In the paper industry, this is called coating, as the applied layer comes from a coating formulation. This layer transforms the material:
- modifies appearance,
- provides barrier properties (water, grease, oxygen, vapor),
- makes paper heat-sealable,
- improves printability and stability,
- strengthens technical properties.
Coating is no longer just a surface treatment; it is a functional transformation.
2- Coating Formulation: The Recipe That Changes Everything
A coating formulation combines:
- mineral pigments (opacity, whiteness, gloss),
- binders (adhesion and cohesion),
- water,
- functional additives tailored to desired performance.
It can provide:
- aesthetic effects (matte, glossy, satin),
- smoother surface,
- water, grease, oxygen, vapor, UV barriers,
- heat-sealability, allowing paper to seal without plastic film.
This property is particularly useful in the plastic-to-paper transition, especially for food packaging.
3- Coated vs Uncoated Paper: Two Worlds
Uncoated paper comes directly from the machine, with natural irregular fibers.
Coated paper receives one or more coating layers, on-line, via coater, or specialized printing unit. It provides:
- uniform surface,
- improved printability,
- enhanced aesthetics,
- superior technical performance,
- integration of barrier and heat-seal properties.
4- Why Coating Changes the Surface ?
Uncoated paper has fibers and hollows. Coating smooths and fills the structure:
- sheet becomes more stable,
- printing gains precision,
- barrier properties are homogeneous,
- heat-sealability is possible.
5- Infinite Technical Combinations
Coating allows:
- single/double-sided, multiple layers, grammages 2–30 g/m²,
- absorbent underlayer + functional top layer,
- barrier formulations (water, vapor, grease, oxygen, UV…),
- heat-sealable, printability optimized for inkjet, flexo, digital.
Two main technologies: plastic film extrusion and aqueous coating. Extrusion: high barriers, heat-seal, more plastic, complex recycling. Aqueous coating: reduces plastic, improves recycling.
6- Why Coating Is Key Today
Industry trends: recyclable substrates, plastic reduction, barrier papers, heat-sealable supports, better print quality.
Coating reconciles performance, industrial constraints, and environmental engagement.
7- Key Takeaways
Coating transforms raw substrate into coated paper with advanced properties: surface improvement, printability, barrier, and heat-sealability.
Our team will help you find the solution that meets your needs.