A coating binder is a substance that is added to a coating formulation to bind the different components of the coating and help it adhere to the surface it is applied to. Coating binders can be organic or inorganic in nature and are typically added in small amounts to the coating formulation. They can be used in a wide range of applications, including paper coatings, paint and varnish formulations, and printing inks. In paper coatings, for example, coating binders are used to help the coating adhere to the paper substrate, improve gloss and brightness, and increase the coating’s resistance to water and other liquids.
Types
There are several types of coating binders used in various industries, including:
- Acrylic binders: These are water-based, fast-drying binders used in a variety of applications, including coatings for paper, wood, and textiles.
- Polyurethane binders: These are used in adhesives, coatings, and paints. They are known for their excellent adhesion, abrasion resistance, and durability.
- Vinyl binders: These are used in coatings, adhesives, and printing inks. They are known for their good adhesion to a wide range of substrates.
- Epoxy binders: These are used in coatings, adhesives, and composites. They are known for their excellent chemical and solvent resistance.
- Alkyd binders: These are used in coatings for wood, metal, and other surfaces. They are known for their durability and resistance to weathering.
- Protein binders: These are used in the food and pharmaceutical industries, as well as in coatings for textiles and paper. Examples include casein and soy protein binders.
- Cellulose binders: These are used in coatings for paper, wood, and other surfaces. Examples include ethyl cellulose and hydroxypropyl cellulose binders.
Applications
Coating binders are used in a wide range of applications, including:
- Paper and paperboard coatings: Coating binders are used in paper and paperboard coatings to improve their printability, brightness, and resistance to water and other liquids. They help to reduce ink absorption and improve color density and sharpness.
- Paints and coatings: Coating binders are used in paints and coatings to provide adhesion, flexibility, and durability. They help to hold the pigment particles together and bond them to the surface being coated.
- Adhesives: Coating binders are used in adhesives to improve their bonding strength and to provide resistance to water and other liquids. They are used in a wide range of applications, including laminates, labels, and tapes.
- Textile coatings: Coating binders are used in textile coatings to provide water resistance, durability, and adhesion. They are used in a wide range of applications, including outdoor fabrics, upholstery, and carpets.
- Construction materials: Coating binders are used in a variety of construction materials, including concrete, mortar, and stucco, to provide strength, durability, and water resistance. They help to improve the bond between the material and the substrate being coated.
Modified starch as coating binder
Modified starch is commonly used as a coating binder in the paper industry due to its unique properties, such as high bonding strength and high viscosity. It can be used as an alternative to synthetic binders, and is a more sustainable option. Modified starch can also provide improved runnability and printability of the paper, and can enhance the paper’s surface properties such as brightness, smoothness, and opacity. Additionally, it can be used in various types of coating formulations, such as pigmented coatings, barrier coatings, and functional coatings. Overall, modified starch is a versatile and cost-effective coating binder option for paper manufacturers.