Low temperature attack, these printing and packaging process details, you pay attention to?
Time:2023-10-09
Views:1417
1. Prevents the rotary offset printing ink from thickening
For the ink, if the room temperature and the liquid temperature of the ink change significantly, the ink flow state will change, and the tone will change accordingly.
At the same time, the low temperature weather will have a significant impact on the ink transfer rate of the highlight part. Therefore, when printing high-end products, in any case, the temperature and humidity of the printing workshop should be controlled. In addition, when using ink in winter, it is necessary to preheat in advance to reduce the temperature change of the ink itself.
Note that the ink is too thick at low temperature and the viscosity is large, but it is best not to adjust its viscosity with diluent or ink oil. Because when the user needs to deploy the ink, the total amount of various additives that the original ink produced by the ink manufacturer can accommodate is limited, beyond the extreme limit, even if it can be used, it also weakens the basic performance of the ink and affects the printing quality of the printing technology.
The thickening of ink caused by temperature can be solved in the following ways:
Note that the ink is too thick at low temperature and the viscosity is large, but it is best not to adjust its viscosity with diluent or ink oil. Because when the user needs to deploy the ink, the total amount of various additives that the original ink produced by the ink manufacturer can accommodate is limited, beyond the extreme limit, even if it can be used, it also weakens the basic performance of the ink and affects the printing quality of the printing technology.
The thickening of ink caused by temperature can be solved in the following ways:
(1) Put the original ink on the radiator or next to the heater, so that it slowly warms up and gradually returns to the original state.
(2) Urgent use can use boiling water for external heating, the specific method is to pour the boiling water into the basin, and then put the original bucket (box) ink in the water, but to prevent water vapor immersion, when the water temperature drops to about 27 degrees Celsius to remove, open the cover and stir evenly can be used. The temperature of the printing workshop should be maintained at about 27 degrees Celsius.
UV varnish is also a material that is easily affected by low temperatures, so many suppliers specialize in producing two different formulations for winter and summer. The solid content of the winter formula is lower than that of the summer formula, so that the leveling performance of the gloss oil can be better when the temperature is lower.
Note that if the winter formula is used in summer, it is easy to cause the oil curing is not complete, and it is easy to cause anti-sticking phenomenon; On the contrary, the summer formula used in winter will cause poor UV oil leveling performance, resulting in foaming and orange peel failure.
2. Use freeze-resistant UV varnish
UV varnish is also a material that is easily affected by low temperatures, so many suppliers specialize in producing two different formulations for winter and summer. The solid content of the winter formula is lower than that of the summer formula, so that the leveling performance of the gloss oil can be better when the temperature is lower.
Note that if the winter formula is used in summer, it is easy to cause the oil curing is not complete, and it is easy to cause anti-sticking phenomenon; On the contrary, the summer formula used in winter will cause poor UV oil leveling performance, resulting in foaming and orange peel failure.
3. The effect of low temperature on paper
In printing production, paper is one of the consumables with high environmental temperature and humidity requirements, paper is a porous substance, its basic structure is composed of plant fibers and auxiliary materials, with strong hydrophilicity, if the environmental temperature and humidity is not well controlled, it will lead to paper deformation, affecting normal printing. Therefore, maintaining the appropriate environmental temperature and humidity is the key to improving the quality of paper printing and improving production efficiency.The requirements of ordinary paper for ambient temperature are not so obvious, but when the ambient temperature is below 10 ° C, ordinary paper will become very "brittle", and the adhesion of the ink layer on its surface will decrease during the printing process, which is easy to cause deinking.
Gold and silver card paper is usually based on coated paper, white board paper, white cardboard, etc., and then composite PET film or aluminum foil and other materials produced, which has higher requirements for environmental temperature. This is because metal and plastic materials are very sensitive to changes in temperature, when the ambient temperature is below 10 ° C, it will greatly affect the adaptability of gold and silver card paper, when the storage ambient temperature of gold and silver card paper is about 0 ° C, from the paper bank to the printing workshop, the surface will appear due to temperature differences and a lot of water vapor, affecting normal printing, and even lead to waste products.
If the above problems are encountered, and the delivery time is tight, the staff can first open the UV lamp to let the paper run empty again, so that its temperature is balanced with the ambient temperature and then formally printed.
In addition, low temperature drying, low relative humidity, paper and air moisture exchange, the paper becomes dry, warped, shrinkage, will cause poor overprinting.
4. The effect of low temperature on glue adhesives
Adhesives are an important chemical agent in industrial production, and the properties of adhesives directly affect the quality of industrial products.
An important technical index in the production of adhesives is the control of temperature. Most of the raw materials of adhesives are organic polymers, which are highly dependent on temperature, which means that their mechanical properties and viscoelasticity are affected by temperature changes. It should be pointed out that low temperature is the culprit of false glue.
When the temperature drops, the hardness of the adhesive becomes hard and the stress action at the adhesive is changed. At the opposite low temperature, the movement of polymer chains in the adhesive is limited, which reduces the elasticity of the adhesive.
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Anna Zhang