Heat transfer printing is a printing process in which the patterns are pre-printed on the temperature-resistant film, and the exquisite patterns on the film are transferred to the product by heating and pressurizing. The process printing method includes two parts: printing of heat transfer film and heat transfer processing. So what factors affect the quality of heat transfer products? This article analyzes and answers the possible reasons for this.
The quality of heat transfer film
The heat transfer film is generally composed of four layers, namely the base layer, release layer, printing layer, and adhesive layer.
Base layer: the carrier of the release layer, printing layer, and adhesive layer – heat transfer base film. The heat transfer base film includes PET film, OPP film, PVC film, etc. the corresponding base film shall be selected according to the needs of specific products, otherwise, the quality of heat transfer products will be affected;
Release layer: it is a layer of release agent coating, which maintains a solid state at room temperature, can melt at a certain temperature, has a smaller adhesion with the base layer, and can quickly separate from the base film without adhesive residue.
Printing layer: this layer is the root of the thermal transfer product pattern to reflect the aesthetic feeling. The key lies in the selection and matching of the thermal transfer ink. After the thermal transfer process is completed, only the printing layer is attached to the surface of the thermal transfer product. Therefore, the selection of the printing layer material is particularly important. A little attention will affect the quality of the thermal transfer product.
Adhesive layer: its actual composition is a kind of hot melt adhesive. According to different substrates, select the corresponding heat transfer glue.
The quality of heat transfer processing
Heat transfer processing is a service process that transfers the heat transfer film to the substrate surface. In this process, several problems need to be paid attention to, otherwise, the quality of heat transfer products will be affected.
- keep the machine clean:
Keep the important parts of the machine clean, free of oil and dust, keep the heat transfer film clean, free of fingerprints and dust, keep the printing products clean, free of dust and oil, and keep the hands of the processors clean, free of oil and sweat;
2. Temperature:
Heat transfer printing temperature has a significant impact on the quality of heat transfer products. Too high a heat transfer temperature may damage the substrate, and too low a heat transfer printing may not achieve normal transfer. The scalding temperature should be determined by the factors of the substrate, flower film, and heat transfer machine. Different materials have different scalding temperatures.
3. Pressure:
The heat transfer printing must be adjusted to the most appropriate level, otherwise, it is easy to hurt the rubber head and the object if it is too large, and it will affect the heat transfer effect if it is too small. After adjusting to the best heat transfer pressure, the pressure should be adjusted and locked to avoid changes in batch production.
4. Speed:
The transfer time (speed) should be determined according to the specific heat transfer materials. Under the condition of ensuring the heat transfer printing effect, the faster the speed, the higher the production efficiency. However, some products must use slow heat transfer printing due to some special conditions.