Why does transparent thermal label paper fade after printing?

Transparent thermal label paper may fade after printing, and the possible reasons include the following:

Thermal paper characteristics:

The production principle of thermal paper is to apply fine particle powder on a regular paper substrate, which consists of colorless dyes such as phenols or other acidic substances, separated by a thin film. Under heating conditions, the film melts and the powder mixes to initiate a color reaction. However, this color reaction is unstable and easily fades, making it difficult to identify the content of the document.

Light and time effects:

Long term exposure to light accelerates the fading of handwriting on thermal paper. This is because the ultraviolet rays in the light will react with the chemicals on the thermal paper, causing the color to gradually disappear.

Over time, the chemicals on the thermal paper will gradually decompose, causing the handwriting to fade.

Environmental temperature:

High temperature environments can accelerate chemical reactions on thermal paper, leading to faster fading of handwriting.

At high temperatures, dyes on thermal paper may decompose faster, thereby reducing the durability of handwriting.

Chemical exposure:

Certain chemicals may damage the coating on the surface of thermal paper, causing the printed content to fade. For example, alkaline substances may react with dyes on thermal paper, causing it to lose color.

Storage and processing methods:

If the printed thermal label paper is placed in a humid environment, the paper may become damp, which may affect the clarity of the printed content.

The use of adhesives or transparent adhesives may accelerate the disappearance of handwriting, as these adhesives may react with chemicals on the thermal paper.

To avoid fading of transparent thermal label paper after printing, the following measures can be taken:

Choose high-quality thermal paper: High quality thermal paper can be stored for longer periods of time, some even up to 30 years or longer.

Avoid high temperatures and direct sunlight: Place the printed thermal label paper in a dark, cool place away from heat sources.

Control humidity: Keep the environment dry and avoid excessive humidity that can cause paper to become damp.

Avoid contact with chemicals: Ensure that the thermal paper does not come into direct contact with chemicals.

Use transparent plastic bags or folders: Seal and package the printed thermal label paper in a transparent plastic bag or folder to effectively prevent dust and other pollutants from entering.

Regularly replace printing paper: For labels or documents that require long-term storage, it is recommended to regularly replace them with new printing paper to ensure the readability of information.

In summary, the fading of transparent thermal label paper after printing is the result of multiple factors working together. By understanding these reasons and taking corresponding preventive measures, the service life of thermal label paper can be effectively extended and the clarity and readability of printed content can be ensured.