What is the thermal coating component of color thermal label paper?

The thermal coating components of color thermal label paper mainly include the following substances:

1.Colorless dye (leuco dye) : This is one of the key ingredients in the thermal coating, it is colorless or light under normal conditions, but under certain conditions (such as thermal stimulation) will undergo chemical reactions and show color. Substances commonly used as colorless dyes include crystal violet lactone (CVL) of triphenylalkylphthalide system, fluorane system, colorless benzoylmethylene blue (BLMB) or spiropyran system. The choice of these dyes determines the type of color that the thermal paper will show when heated.

2.Color developer: Color developer is another key component in thermal coatings that chemically reacts with colorless dyes and produces color. The substances commonly used as color developing agents are para-hydroxybenzoic acid and its esters (such as PHBB, PHB), salicylic acid, 2, 4-dihydroxybenzoic acid or aromatic sulfone. The chromogenic agent reacts with the colorless dye under thermal stimulation to produce the desired color.

3.Sensitizer: The sensitizer plays a role in enhancing the sensitivity of chemical reactions in the thermal coating, which can help improve the printing quality and reaction speed of the thermal paper. The sensitizer often contains benzene sulfonamide compounds.

4.Fillers: fillers play a role in filling and adjusting the performance of the coating in the thermal sensitive coating, which can help improve the density and gloss of the thermal sensitive paper. Commonly used fillers include calcium carbonate (particles), etc.

5.Adhesives: Adhesives are mainly used to adhere colorless dyes, color developing agents, sensitizers and other components to the paper to form a stable heat-sensitive coating. Commonly used adhesives are polyvinyl acetate and so on.

6.Other auxiliaries: In addition to the above main ingredients, other auxiliaries such as stabilizers and lubricants may be included in the thermal coating to improve the stability and printing performance of the thermal paper.

It should be noted that different brands and models of color thermal label paper may differ in the composition of thermal coating, and the specific composition and ratio will be adjusted according to product characteristics and application needs. In addition, the uniformity of the thermal coating and the rationality of the chemical formulation have an important impact on the printing quality and storage time of the thermal paper.