What are the main raw materials of transparent thermal label paper?

The main raw materials of transparent thermal label paper include the following aspects:

1. Substrate

PET (polyethylene terephthalate) : Transparent thermal label paper is usually used as a substrate, PET material has good stability and durability, to ensure that the label in a variety of environments remain flat and deformation.

2. Heat sensitive coating

Colorless dyes: Colorless dyes contained in thermal coatings change color when heated to form visible images or text. There are a variety of these dyes, the most commonly used being fluorane compounds.

Color developing agent: The color developing agent interacts with the colorless dye and causes the dye to develop color when heated. Common color developing agents are bisphenol A, parabens and so on.

Sensitizer: Sensitizer can enhance the sensitivity of the heat-sensitive coating, so that the dye can be colored at a lower temperature. Benzene sulfonamide compounds are commonly used as sensitizers.

Fillers: Fillers such as calcium carbonate are used to improve the opacity of the paper and enhance the contrast between the image and the background color.

Adhesive: The coating has good surface strength and printing performance, while forming a colloidal protective film between the dye and the color developer to prevent premature reaction between the two. Commonly used adhesives are polyvinyl acetate and so on.

Stabilizers: used to improve the stability of heat-sensitive coatings and prevent their performance changes during storage and use.

Lubricant: Usually a waxy substance used to prevent the print head from sticking during the printing process.

3. Glue back

Adhesive: The back of the transparent heat-sensitive label paper is coated with adhesive for attaching the label firmly to the surface of the object. There are various types of adhesives, including general super adhesive, general strong adhesive, refrigerated food strong adhesive, etc., to meet the needs of different application scenarios.

4. Backing paper

Release paper: commonly known as "bottom paper", the surface is non-sticky with low surface energy, and has an isolating effect on the adhesive, so that the face paper can be easily peeled off from the bottom paper. Common base paper materials are white, blue, yellow glassine paper (glassine) or onion paper (onion), kraft paper and so on.

In summary, the main raw materials of transparent thermal label paper include PET substrate, thermal coating (colorless dyes, color developing agents, sensitizers, fillers, adhesives, stabilizers, lubricants), back adhesive and backing paper. These raw materials together constitute transparent heat-sensitive label paper, making it have good printing effect, stability and durability.