The coating process used for white cardboard coated paper

The coating process used for white cardboard coated paper involves applying a layer of coating material onto the surface of the paper substrate. This coating serves several purposes, including enhancing the paper's printability, improving its appearance, and adding protective qualities. There are typically two main types of coatings used: clay coating and matte or gloss coating.

Here's an overview of the coating process for white cardboard coated paper:

    Preparation of Paper Substrate: The base paper, often a high-quality cardboard or paperboard, is prepared for the coating process. This paper provides the structural integrity and bulk of the final product.

    Coating Formulation: The coating material is formulated based on the desired characteristics of the final paper. The coating mixture typically includes various components such as pigments, binders, additives, and solvents.

    Coating Application: The formulated coating is applied to the paper substrate using specialized coating machines. There are different methods for applying the coating, including:

        Roller Coating: In this method, the paper passes through rollers that evenly distribute the coating mixture onto the paper surface.

        Air Knife Coating: Air pressure is used to control the thickness of the coating layer as the paper passes through a narrow gap, ensuring consistent application.

        Size Press Coating: The paper is passed through a bath of the coating mixture, and excess coating is removed by rollers to achieve a controlled coat weight.

    Drying and Curing: After the coating is applied, the paper goes through a drying and curing process. This can involve passing the paper through heated drying chambers or using infrared or ultraviolet (UV) lamps to evaporate solvents and solidify the coating. This step is crucial to ensure proper adhesion of the coating to the paper substrate.

    Calendering (Optional): In some cases, the coated paper might undergo calendering, which involves passing the paper through a series of rollers under pressure. Calendering can improve the smoothness, gloss, and overall finish of the paper surface.

    Finishing: Once the coating is dried and cured, the paper might undergo additional finishing processes such as cutting, trimming, and packaging, depending on its intended use.

The type of coating used—whether it's clay-based, matte, or gloss—depends on the desired properties of the final paper. Clay coating, for example, provides a smooth and glossy surface that enhances print quality and color vibrancy. Matte coating offers a softer, non-reflective finish. Both types of coatings contribute to improved ink holdout, reduced ink absorption, and protection against wear and tear.