How to choose the ink suitable for film screen printing

At present, plastics can be used to make a wide variety of molded products. The color of the concave plastic molded product is generally a single color. In order to decorate plastic molded products, other fields of technology must also be applied, including the use of injection mold technology to make color patterns. If it is a large pattern, it may be bi-color or tri-color; if it is a small pattern, it may only be monochrome. Generally use screen printing, or gravure. Can also be used laser processing, corrosion processing, labeling and other methods. In this paper, injection mold processing is performed on already printed sheets or on already formed sheets. This treatment is called IMD (formable surface decoration technology).

Printing on the sheet, and shaping, and then stripping the carrier, the ink pattern will be transferred out. Therefore, it must be protected. According to market demand, text and graphics must not fall off. For example, if a black safety channel light is printed on the front of the graphic, if the black ink on the printed graphic comes off, the mark cannot be seen. This is absolutely not acceptable.

According to the market demand, it is necessary to adapt to the production of small-volume products, fast-acting, and quick product updates. For example, the surface like woodgrain pattern, color, customer demand is constantly changing, which is also the market demand. The market sometimes only needs 5000, 10,000 products, requiring manufacturers to adapt to changes in the market. Automobiles and home appliances are constantly updated. This is a market trend.

The initial ultrahigh-pressure molding process applied screen printing. After the film is printed on the screen, it is then processed by molding, cutting, coating, and final molding. The key to this process is screen printing inks. The ink is in the middle of the film and behind the resin. But why is this production method not yet formed into a market? The main reason is that the injection mold manufacturing process is very difficult. Ultra-high pressure molding production process, we must have special screen printing ink.

This special screen printing ink must meet the following conditions:

1, screen printing ink must be high temperature. The resin used in the injection mold process reaches a temperature of about 3000°C. If it does not reach this temperature, it will not melt, and the resin will flow away when it encounters the ink;
2, after the printing ink, forming processing. Screen printing ink must withstand shrinkage;
3. When the finished product is finished, the surface sheet, the screen printing ink in the middle, and the internal resin, these three layers of different substances must be closely combined.

Screen printing inks capable of satisfying the conditions of high temperature resistance and adhesiveness have not been developed so far and have become subjects of research.

The company that originally proposed the ultra-high pressure molding process developed a carbonic acid resin and started a joint research with another company to find a suitable screen printing ink. In 1988, colloidal inks were developed. However, colloidal inks did not meet the printing conditions and were immature products. In 1997, it developed a high temperature fission screen printing ink.

Products made using high temperature fission screen printing inks have a car heater control panel. This type of car has already been sold in Japan. From the beginning of auto parts, to the use of portable ink pad, decorative window, dashboard, etc., are widely used.

High temperature fission screen printing ink, high temperature resistance, mainly composed of polycarbonate resin. The ink has a good fastness to the polycarbonate resin, and also has good adhesion with other resins. It is a solvent-based resin and is a single-liquid screen printing ink, and has adhesiveness with various materials. The use of ultra-high pressure molding process technology, polycarbonate resin as the substrate, printing high-temperature fission screen printing ink, to achieve satisfactory results.

Cloakroom fission screen printing ink, with good alcohol resistance, good softness, no blistering, high temperature resistance. The softening point is between 160 and 170°C (ordinary ink between 80 and 100°C). Ink color is complete, there are also three primary colors ink for color printing. The ink has good transmissivity and can meet the requirements of commodity color and meet the designer's imaginative color requirements. Companies such as Motorola and Ericsson applied the ink.

Silk screen printing and various technologies want to combine, and constantly research and develop new technologies. When printing the dials of various devices, the automation of the molding process should be considered to adapt to changes in market demand.