In cold weather, what should be paid attention to in packaging printing?

With the arrival of cold air, some printing processes will also be affected by low temperature weather. The printing environment should be constant temperature and humidity, which not only helps prevent paper deformation and improves product overprint accuracy, but also ensures the printing adaptability of the ink. If the printing temperature is too low, it will bring some practical difficulties and process failures to printing production.

So, in this low-temperature weather, what details should be paid attention to in packaging printing, and how can we not be affected by temperature during the printing process?

Prevents web offset ink from thickening

For ink, if the room temperature and the liquid temperature of the ink change significantly, the ink flow state will change, and the color tone will also change accordingly.

At the same time, low-temperature weather will have a significant impact on the ink transfer rate of high-gloss areas. Therefore, when printing high-end products, the temperature and humidity of the printing workshop must be controlled anyway. In addition, when using ink in winter, it is necessary to preheat it in advance to reduce the temperature change of the ink itself.

Note that the ink is too thick and viscous at low temperatures, but it is best not to use thinner or ink-adjusting oil to adjust its viscosity.

Because when users need to adjust ink properties, the total amount of various additives that can be accommodated by the original ink produced by the ink manufacturer is limited. If the amount exceeds the limit, even if it can be used, it will weaken the basic performance of the ink and affect printing. Quality printing technology.

The thickening of ink caused by temperature can be solved by the following methods:
Place the original ink on the radiator or next to the heater and let it slowly heat up and gradually return to its original state.
In case of emergency, boiling water can be used for external heating. The specific method is to pour the boiling water into a basin, and then put the original barrel (box) of ink in the water, but prevent water vapor from infiltrating. When the water temperature drops to about 27 degrees Celsius, take it out and open it. Cover and stir evenly before use. The temperature of the printing workshop should be kept at around 27 degrees Celsius.

Use antifreeze UV varnish

UV varnish is also a material that is easily affected by low temperatures. Therefore, many suppliers specialize in producing two different formulas, winter and summer. The winter formula has a lower solid content than the summer formula, which can make the leveling performance of the varnish better when the temperature is lower.

Note that if you use a winter formula in summer, it will easily cause the oil to be incompletely cured and may lead to back-sticking. On the contrary, if you use a summer formula in winter, it will cause poor leveling performance of the UV oil, causing blistering and orange peel problems. 

The impact of low temperature weather on paper

In printing production, paper is one of the consumables that has extremely high requirements on environmental temperature and humidity. Paper is a porous material, and its basic structure is composed of plant fibers and auxiliary materials. It has strong hydrophilicity. If the environmental temperature and humidity are not good, Control will cause paper deformation and affect normal printing. Therefore, maintaining appropriate environmental temperature and humidity is the key to improving paper print quality and increasing production efficiency.

Ordinary paper has less obvious requirements for ambient temperature, but when the ambient temperature is lower than 10°C, ordinary paper will become very "brittle", and the adhesion of the ink layer on its surface will decrease during the printing process, easily causing delamination. Ink phenomenon.

Gold and silver card paper is usually produced using coated paper, white board paper, white cardboard, etc. as base materials, and then compounded with materials such as PET film or aluminum foil. It has higher environmental temperature requirements. This is because metal and plastic materials are very sensitive to temperature changes. When the ambient temperature is lower than 10°C, it will greatly affect the suitability of gold and silver card paper. When the storage environment temperature of gold and silver card paper is around 0°C, After being transported from the paper warehouse to the printing workshop, a large amount of water vapor will appear on the surface due to the temperature difference, which will affect normal printing and even lead to waste products.

If you encounter the above problems and the delivery time is tight, the staff can first turn on the UV lamp and let the paper run dry to make its temperature equal to the ambient temperature before formal printing.

In addition, low temperature drying and low relative humidity will cause moisture exchange between the paper and the air, causing the paper to dry, warp, and shrink, which will cause poor overprinting.

Effect of low temperature on glue adhesives

Adhesive is an important chemical agent in today's industrial production. The performance of the adhesive directly affects the quality of industrial products.

An important technical indicator in adhesive production is temperature control. Most of the raw materials for adhesives are organic polymers, which are highly dependent on temperature, which means that their mechanical properties and viscoelasticity are affected by changes in temperature. Influence. It should be pointed out that low temperature is the culprit of false stickiness of glue.

When the temperature drops, the hardness of the adhesive becomes harder, changing the stress effect on the adhesive. In the opposite low temperature state, the movement of the polymer chains in the adhesive is restricted, reducing the elasticity of the adhesive.



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