Heat transfer film is very common in life, such as the pattern on the T-shirt. The production process is to transfer the pattern of the film to the surface of the carrier through preheating pressure, so as to meet various pattern requirements. Most of the substrates are made of PET. The sheet is the main material. After the pattern is printed on the PET sheet, hot melt adhesive is applied to the back of the pattern. The hot melt adhesive combines the pattern with the clothing, and the PET waste film is removed to complete the thermal transfer process.
Heat transfer film includes release film, glue, ink and other chemical materials printed. PET release film is a very mature material, usually a silicone oil release film, but when applied to a heat transfer film, the silicone oil release film cannot adapt. Therefore, the unique release coating of heat transfer is derived, which can meet the release effect and the effect of perfect ink printing. Therefore, the price of heat transfer film in the market is relatively high, the technical threshold is high and the formula is complex.
In order to balance the two aspects of release and printing, it is usually necessary to change the release coating formula. The release formula needs to match the ink layer. When pure silicone oil is used as the release agent, the surface tension of the coating is too low, which is the direct cause of the ink printing unable to hang and bloom. reason. When pure resin material is used, printing is possible, but there is no release effect. The usual practice is to add release silicone oil to the coating resin to balance the printing effect and the release effect. The surface energy of silicone oil is extremely low and the compatibility with resin is poor, so some special surfactants, diluents, leveling agents, defoamers, etc. will be added to adjust and improve the formula. The addition ratio of silicone oil is not 1-30%. And so on, try repeatedly to get the final ideal addition ratio.
Component A: 40 parts of saturated polyester resin, 5 parts of silicone oil, 0.5 part of organo-modified polysiloxane defoamer, 3 parts of polysiloxane-polyether copolymer leveling agent, 51.5 parts of aliphatic hydrocarbon C6-C8 solvent share.
Component B: curing agent amino resin 4 parts. Mix evenly before use. The prepared product must be used up within 15 hours. The drying temperature is 100-130°C, and the 300-mesh anilox roller is applied. Repeatedly apply 3-4 times to make the release layer reach The thickness of 6 microns, so that the release layer after thermal transfer can achieve the effect of oil injection, the surface is hard and friction-resistant.
The release coating with added silicone oil is more suitable for the tear-off process of hot tearing. The temperature resistance of silicone is higher, generally above 150-180 °C. At present, heat transfer heat transfer release agents are still mainly oil-based materials. Due to environmental protection issues, they will be developed to water-based and UV systems in the future. Silicone oil is only one component in the formula. With the update and iteration of downstream applications, a variety of types will be developed, and materials such as wax and fluorine are also selected to improve the release effect.