What are the production processes of long-lasting three proof thermal paper?

The production process of long-lasting three proof thermal paper usually includes the following main steps:

1、 Raw material preparation

Pulp selection and pulping:

Select high-quality wood pulp as raw materials, such as coniferous wood pulp and broad-leaved wood pulp, and mix them in a certain proportion.

Perform pulp beating treatment, adjust the beating concentration and free degree to obtain ideal fiber morphology and paper properties.

Thermal sensitive pigments mixed with additives:

Mix heat sensitive pigments (such as colorless dyes, phenols, or other acidic substances), color developing agents, sensitizers, stabilizers, and other chemical substances according to the formula ratio evenly to make heat sensitive coatings.

Other additives such as waterproofing agents, oil proofing agents, etc. may be added as needed to improve the "three proofing" performance of the paper.

2、 Coating process

Pre coating coating:

Use a coating with relatively coarse particle size for the first pre coating to form the first pre coating layer. This coating may contain dispersants, inorganic pigments, and other components to improve the smoothness and ink absorption of the paper.

Thermal sensitive coating application:

On top of the pre coating, apply a thermosensitive coating to form a thermosensitive coating. This layer of coating is a key part of the color development of thermal paper, and its thickness and uniformity directly affect the printing effect.

Protective layer coating (optional):

In order to improve the durability and anti pollution ability of paper, sometimes an additional protective layer is applied on top of the thermal sensitive coating. This protective layer may contain components such as zinc stearate, polyvinyl alcohol, and polyethylene wax micro particles, which have functions such as waterproofing, oil resistance, and friction resistance.

Coating method:

By using methods such as roller coating, spray coating, metering rod coating, or film transfer coating, the coating is evenly applied to the surface of the paper.

3、 Drying and solidification

Drying treatment:

After coating, the paper needs to be dried to remove moisture from the coating and ensure that the coating adheres firmly to the paper.

Drying methods include natural air drying, oven drying, airflow drying, UV lamp rapid drying, etc.

Curing treatment:

In some cases, it is also necessary to cure the dried paper to improve the stability and durability of the coating.

4、 Cutting and packaging

Cutting processing:

According to customer requirements, cut the dried and cured paper into the required size to form single sheet or roll thermal paper.

Packaging treatment:

Pack the cut thermal paper to prevent moisture, contamination, and damage. The packaging material is usually moisture-proof paper or plastic film, and is labeled with relevant product information and usage instructions.

5、 Quality inspection

Throughout the entire production process, strict quality testing is required for raw materials, semi-finished products, and finished products to ensure that the quality of thermal paper meets standards and customer requirements. The testing content includes the flatness of the paper, the uniformity of the coating, the printing effect, durability, and the "three proof" performance.

6、 Special process (optional)

According to customer needs, special treatments such as die-cutting, hot stamping, and laminating can also be performed on thermal paper to increase the added value and aesthetics of the product.

In summary, the production process of long-lasting three proof thermal paper is a complex and delicate process that requires strict control of each link to ensure product quality.