What are the precautions for using nylon powder?

2022/09/01

What are the precautions for using nylon powder?

Seasonal climate change is a change in ambient humidity and temperature. Specifically, in spring and summer, especially the rainy season, the relative humidity in the air is high, even reaching saturation. In autumn and winter, the air is dry and the humidity is low; as far as the temperature is concerned, summer is much higher than winter, and the difference between the two can be nearly 30~40, so what are the precautions for using nylon powder?

What are the precautions for using nylon powder?

If these differences are not noted, it is likely that during printing and lamination, the adhesive is not dry enough, the residual viscosity is high, and the lamination film even delaminates when peeled off. Especially the high hygroscopicity of nylon film is more likely to cause this phenomenon.

1. Nylon powder strictly controls the temperature and humidity changes in the production environment; due to the moisture absorption of nylon film and a series of adverse consequences caused by moisture absorption, it is very important for the use environment and storage environment of nylon film.

2. Nylon powder should be careful when the humidity exceeds 70%RH. When the temperature is low or the humidity is too high, be sure to turn on the preheating device of the printing compound machine. The nylon film is preheated first, and the moisture attached to the surface of the nylon film is dried, so as to facilitate the smooth progress of printing and composite production. Due to the large temperature changes at the turn of winter and spring, the use of mixed solvents should be effectively adjusted with the changes in temperature to prevent excessive solvent volatilization or excessive residual solvent from causing quality accidents. The environmental control of the workshop can keep the humidity at 50%~60%RH, and the temperature in summer at 20~22.

3. During the drying and solvent-free compounding process of nylon powder, different types of two-component polyurethane adhesives have different sensitivities to water and alcohol. Exceeding the scope may result in inaction. If the sensitivity is out of range, the higher the sensitivity, the less flexible it is, and sometimes the composite product becomes hard and brittle. So the compound effect will be seriously affected.

4. For materials with strong hygroscopicity such as nylon powder cellophane, it is necessary to strictly manage and control the residual solvent after printing and the humidity in the air. The stress-strain curve of nylon membrane changed obviously after moisture absorption. After the nylon film absorbs moisture, it will not have a great impact on the corona effect, but has a great impact on the adhesion of ink and adhesives. Generally, when the moisture content of nylon film exceeds 3%, it will not only affect the adhesion of ink and adhesive, but also make the film feel stiff and yellow, affecting the appearance. Therefore, special attention should be paid to the storage and use of nylon film to prevent moisture absorption, and use as little or no alcohol as possible when printing

5. Nylon powder comes with polyurethane resin ink. When using polyurethane resin ink, pay attention to adding little or no alcohol to dilute the solvent.

6. Nylon powder is useless because it is solvent-free, so there is no solvent residue problem. Solvent-free compounding cannot reduce solvent residues caused by printing, so higher requirements are placed on the control of solvent residues in printing. Solvent-free composite adhesives do not contain organic solvents and do not increase residual solvents, but at the same time do not reduce residual solvents caused by printing. Films for water-based ink printing are randomly corona treated prior to printing to ensure ink-to-film adhesion. When printing with white ink primer, add a small amount of general curing agent to white ink to improve compound fastness. After printing, composite production should be carried out as soon as possible. The rest of the material can be wrapped in a wrapping film containing aluminum foil to prevent moisture from invading the air and getting damp. The remaining film should be placed in a dry and ventilated place, and then placed in the curing room 2 to 3 hours in advance to dry the water vapor on the surface of the nylon film, which can protect the material from moisture and affect product quality.

 

Key words:

nylon powder,transparent nylon,Nylon 12

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