Analysis of the Reasons for the Bending of Plastic Film Color Printing Trademarks

The printing industry in the modern printing industry develops from monochrome to six-color and eight-color. The efficiency has evolved from multi-process to one-step molding, integrating printing, cutting, embossing, bronzing, and laser.
In the process of mechatronics, a series of new problems will inevitably arise in production. Trademark bending is a quality problem often encountered in the production of one-shot molding. Trademark bending not only affects the appearance of the trademark, but also directly impairs the user's applicability to the computer, causing users to discontinue their use of the trademark.
How to effectively solve and control the occurrence of trademark bending in production is of great significance to improving product quality and satisfying users' needs.
From the test, it is known that under a certain pressure and temperature conditions, the greater the tensile force, the higher the temperature, the greater the deformation of the film.
In the process of one-step forming of gravure multi-color machine, the film is subjected to 20dan to 35dan tensile force, 25dan to 40dan pressure, drying temperature 60°C to 100°C, and after several times of printing and drying, stretching, and recovery, deformation occurs to varying degrees. , And in the printing, due to the application of ink, but also will cause the film surface lateral amplitude of the local and the positive and the outer side of the two different stretching, deformation, recovery, and thus appear in the finished product trademark bending phenomenon, especially the poor tension formation The quality of the film will be severely curved.
For the bending phenomenon in the production of trademarks, the following measures can be taken:
(I) Thin film control In order to reduce the bending of the trademark, it is necessary to reasonably select the famous brand with high technical content in selecting the brand of the printed film, which can ensure the reliability of the pp resin, the reliable control of the thickness and thickness uniformity of the film, and the uniform slitting and rewinding tension. Ensure that the surface condition and tension of the film are balanced, which is beneficial to printing and avoiding bending.
(2) Control of ink and solvent In the printing process, ink is applied on one side of the film, and the ink, resin, trademark pattern, and solvent are volatilized, which have different degrees of influence on the bending of the trademark. Under the premise of guaranteeing the pattern and color to meet the needs of users, the ink's origin, applied thickness, and choice of solvent should be compared. The ink must be selected for its strong solubility, good performance, and low susceptibility to sizing. The thickness is in the platemaking process according to product requirements. Net depth is generally not more than 35μm; the use of solvents must maintain a balanced mixture of solvents, that is not too volatile, but also at a certain temperature (usually does not exceed 80 °C), so that the product does not stick.
(C) the speed of the car, the coordination of tension in the printing process under certain conditions of the pull, the higher the printing speed, the greater the degree of trademark bending; the other hand, the printing speed is constant, the greater the pull, the greater the trademark bending. In the production of equipment to play the efficiency, can not reduce the speed to solve the problem of trademark bending, which must be a reasonable choice of tension parameters to solve quality problems. For example, in the running speed is 130m/min, the tension before the tension of 20dan, the rear tension of 35dan is a more ideal parameter, as for the choice of actual parameters, according to the printing effect adjustment.
(4) Influence of drying temperature and air volume The higher the temperature in the drying oven, the better the printing process. However, if the temperature is too high, the trademark bending phenomenon will occur. Therefore, the temperature is generally stable at 55°C to 90° for layered printing. °C, the inlet pressure and exhaust pressure of the drying oven must be balanced. If the air volume is too large, the shrinkage of the film is large and the trademark is severely curved.
(5) The effect of ink, printing patterns, and solvents on the bending of the trademark (as listed in the following table)

Bending degree Varnish printing area Solvent large domestic full version Volatile fast Chinese brand name Strip Volatile small and medium import Irregular volatilization Slow