The factors that have great influence on flexible packaging include temperature, humidity, static electricity, friction coefficient, additives and mechanical changes. The humidity of the drying medium (air) has a great impact on the amount of residual solvent and the rate of volatilization. Today, we mainly analyze the humidity for you.
一、 Influence of humidity on printing packaging
1. Effects of high humidity:
① High humidity causes deformation of the film material, resulting in insufficient chromatic accuracy
② High humidity will promote mold growth and cause mildew of packaging and materials
③ Under high humidity, the ink resin will be emulsified, resulting in the loss of print gloss and ink adhesion
④ Due to the high humidity and the solvent volatilization, it is very easy to cause the ink surface to be dry and the ink inside to be dry, and in serious cases, the ink will be scrapped due to anti-sticking
2. Effects of low humidity:
① If the humidity is too low, the film material will lose water and cause hardening or dry cracking
② Too low humidity will increase static electricity. Special attention should be paid to the static electricity fire prevention in the workshop for flexible packaging
③ If the humidity is too low, the static electricity of the material will be too large, and there will be electrostatic whiskers or ink spots on the film during printing;
④ Too low humidity leads to too much static electricity on the film surface, which makes it difficult to manage the bag, and it is not easy to tidy, and it is difficult to print code
二、 How to control the humidity in the printing workshop
1. How to avoid high humidity environment
In the case of high humidity, we need to conduct closed dehumidification in the workshop as much as possible; In sunny and dry days, moderate ventilation management is required to reduce humidity.
If conditions permit, dehumidification devices shall be installed in the workshop for dehumidification under high humidity conditions. The raw and auxiliary materials shall be subject to strict moisture-proof management. The film materials shall be well packaged and placed on pallets or materials. The workshops and warehouses shall not be built in places prone to moisture. Under high humidity conditions, the electrical cabinet should be kept sealed as far as possible, and the electrical components should be regularly checked and properly moisture-proof maintained to avoid equipment failure.
2. How to avoid low humidity environment
In the case of low humidity, we mainly consider the problem of water loss and static electricity of materials, especially the fire in our flexible packaging industry, more than 80% of which is caused by static electricity!
Therefore, in addition to the necessary grounding connection, the machine must be equipped with a workshop humidifier to eliminate static electricity in low humidity environment to ensure safety. It is recommended that each work unit should be equipped with a workshop humidifier, which will ensure the safety of the whole production and is also very beneficial to the stability of quality.
三、 Methods of controlling humidity in printing workshop
The optimum working environment temperature for paper printing is 18~23 ℃. The relative humidity of the workshop can be controlled at 55%~65% RH by using industrial humidifier, and the stable humidity of the workshop can reduce the paper deformation, misregister and static electricity.
Common humidifiers include high-pressure mist humidifier, two-fluid humidifier JS-GW-1, two-fluid humidifier JS-GW-4, ultrasonic humidifier, etc.
Post time: Feb-28-2023