Application of Thermal Transfer Technology in Pharmaceutical Flexible Packaging

Thermal transfer is an emerging printing process that has been introduced from abroad for more than 10 years. Started by some early foreign investors investing in mainland China to bring it to China, the use of raw materials is also mainly imported. When foreign companies introduce flexible packaging technology into China, the domestic demand for this technology also arises.

In the past, most domestic infusions were bottled in glass bottles, and labels were mainly in the form of stickers. Due to defects in glass bottles and utensils, for example, it is unsafe to break, contamination is caused by repeated use, and air pollution from back injection into the bottle is used. Therefore, foreign countries have already replaced glass bottles with flexible packaging. With the continuous development of China's medical and health undertakings, the improvement of people’s living standards and spending power and the requirements for the pharmaceutical industry are gradually in line with international standards. The State Food and Drug Administration has made many restrictions on the application of glass bottles in recent years. At the same time, the market demand for infusion continues to rise, so the demand for infusion flexible packaging in the domestic market has also risen. In this case, the application of thermal transfer technology on flexible packaging has also been greatly popularized.

Thermal transfer technology is not unfamiliar to soft packaging. For example, batch number, shelf life, etc. of triple coffee, etc., have many applications. The principle is similar to that of the old mechanical typewriter, and the pigment on the film is transferred to the product by the heated characters. Application on infusion soft packs is more typical. Because infusion is not an OTC drug, it is not practical to be effective on the packaging, so the printing on the infusion packaging bag is a thermal transfer method. Its technical requirements can be summarized as follows:

First, non-toxic and harmless, that is, its material composition requirements. The material of the thermal transfer film for drug packages on the existing market basically comprises: the base material is PE; the transfer portion is a pigment and resin particles.

Second, the transfer effect. Including three aspects, that is, the printing effect, adhesion effect and transfer to the outer bag after sterilization. That is, the print should be clear in order to read the content. Because the printed contents are mostly drug instructions, the requirements for sharpness are quite high. Adhesion is a phenomenon that cannot be peeled off and transferred to another object after printing. Because the flexible packaging infusion has a tight contact with the inner and outer packaging during the sterilization process and requires a prolonged high temperature process, the pigment is required to withstand high temperatures.

Third, the pigment and its carrier must be able to withstand high temperatures. Because the sterilizing temperature of the soft packaging infusion is above 110 degrees Celsius, the pigments are required to remain unchanged after the high temperature and pressure, and remain stable during the product's effective period.

Fourth, printing temperature and pressure control. This is a requirement for a printer. With regard to the current level of mechanical technology, it is not too complicated to maintain and control after setting the print temperature; the pressure setting is even simpler.

Fifth, the template, that is, the requirements of printing fonts. Corresponding to different packaging materials, there are different requirements for the thermal conductivity of the template. The basic material of the template is copper, zinc iron, aluminum alloy and so on. More importantly, there must be no surface burrs for the printing of flexible packaging, which means that the post-processing of the surface of the stencil is strictly required.

The thermal transfer industry has developed very well abroad. There are many multinational corporations in the United States, Australia and other countries producing thermal transfer film, printers and supporting high-quality printing fonts, and they are widely used in the pharmaceutical flexible packaging industry. .

In China, the entire thermal transfer industry has experienced a stage from scratch and gradually matured. The development in recent years is as described above and related to the country's restrictions on glass bottle infusions. Now basically has developed into a complete supporting system, including the manufacture of thermal transfer machines, printing films and printing stencils. In the manufacture of printed films, there is still a considerable gap between domestic and foreign standards. The main problems are uneven coating and poor adhesion.

With the rapid development of domestic economic development and health care, the rapid increase in demand for flexible packaging infusion markets is bound to vigorously promote the application of thermal transfer technology in the pharmaceutical industry, thus promoting the development of a range of domestic industries, especially thermal transfer. Membrane research and production. Now there are many companies in the domestic production of heat transfer film for non-PVC and PVC flexible packaging bags, and their performance is constantly improving.

From the above factors, the demand for this type of printing will be more and more, and the requirements for domestic supporting industries are also getting higher and higher. On the other hand, with the development of supporting industries, the application of thermal transfer printing It will also become more economical and popular.