The working area of laminating thermocompression is very narrow, only 5-20mm.
The normal working time is about 0.1 ~ 0.2s.
The lamination of pre-coated film and paper print is completed in such a narrow working area and within such a very short working time.
The working time, that is, the running speed, determines the order of the working temperature conduction process and the gradual transformation process of the adhesive layer, the pros and cons of wetting the surface of the printed product to be processed, and at the same time determines the dispersion state of the hot melt adhesive particles and the strength of the bonding.
Relatively speaking, the working time is long, the hot melt adhesive is fully melted, the surface of the printed product is fully wetted, and it forms a dispersive diffusion to the ink layer and paper, and the bonding fastness is strong.
On the contrary, the working time is short, and the set T temperature will be able to realize the gradual morphological transformation of the hot melt adhesive according to the conduction distance and sequence in the future, and it is also impossible to form the molecular dispersion, infiltration and affinity between the hot melt adhesive molecules and the ink layer and paper fibers. , resulting in poor wettability and weak adhesion.
The seemingly bonding is actually only the effect of the viscosity of the tackifying material when the temperature is lower than the required working temperature;
After cooling, the viscosity and fluidity during heating return to their original low-temperature brittleness, and they cannot withstand the impact of external forces and heating after lamination, resulting in creases or blisters.
According to the test of the effect of compounding the pre-coating film and various paper prints under the conditions of the same temperature, the same pressure and different speed changes, the pre-coating film lamination speed is standardized as follows:
①The range of working speed is generally 6～12m/min;
② In the case of high basis weight, high tightness, high water content, dust, large ink layer area, dark color, low working environment temperature, high humidity, fast gas flow, poor brightness of composite products, etc., the working speed should be appropriately reduced. , whichever is better for the composite effect;
③ For the set working area of 6-12m/min, if the production speed is adjusted in increments of 1m/min, the average working temperature will drop by 3.4%, and the working pressure will drop by 9.4%;
④ In the working area of 12m/min < running speed ≤ 15m/min, if the production speed is still adjusted in increments of 1m/min, the output value of each level variable will change sharply.