Thermal film are made of bopp With eva coating 。

Pre coating refers to the process of pre gluing and rewinding plastic film, and then laminating it with printed paper. It is first coated on a film by a pre coating processing factory according to the specifications and format, and then rewound for the manufacturer to choose from, and then combined with printed materials. Film coating, also known as film sticking, is a processing technology that applies adhesive to plastic film, and after heating and applying pressure to paper printed products, they are bonded together to form a paper plastic integrated product. Printed products coated with plastic film have a smooth and shiny surface due to the addition of a thin and transparent plastic film, which improves the glossiness and fastness of the printed products. The graphic and text colors are more vivid and three-dimensional, while also playing a role in waterproofing, stain resistance, wear resistance, folding resistance, chemical corrosion resistance, etc.

The pre coating film is composed of a substrate and an adhesive layer. The substrate is usually a polyester (PET) film and a biaxially oriented polypropylene (BOPP) film. BOPP film has the characteristics of high transparency, good brightness, non-toxic and odorless properties, water resistance, heat resistance, low cost, and soft texture. It is an ideal material in the laminating process, with a thickness of about 12-20um. Therefore, from the perspective of material cost and processing technology, the vast majority of pre coated substrates use BOPP film.

There are two types of adhesive layers for pre coated films: melt type and solvent volatile type. Depending on the processing equipment and process conditions, different thicknesses of adhesive layers are selected, and the thickness of the adhesive layer is generally between 5-15um. The adhesive layer of domestic pre coated film is mainly composed of hot melt adhesive or organic polymer low-temperature resin. Hot melt adhesive is made by blending and modifying several materials such as main adhesive resin, tackifiers, and modifiers. Organic polymer resin is a single polymer low-temperature copolymer. Due to the fact that hot melt adhesive is a mixture of several materials, the transparency of the coated film is significantly lower than that of low-temperature pure resin pre coated films.

The production process of solvent evaporation type pre coating film is similar to that of instant coating film process. Organic solvents are used to dissolve colloids and then coated on the film substrate. Therefore, there may be problems such as incomplete evaporation of organic solvents, odor during coating operation, and harm to operators (compared to instant coating film process, the harm is much smaller). After coating, solvent evaporation can also easily form bubbles on the surface of printed materials.