Analysis And Solve The Undesirable Phenomenon In Solventless Composite

2021-04-13

Here, we give a detailed analysis of the undesirable phenomenon in the solventless composite and solventless laminating machine, such as the uniform winding, poor coating effect, etc and how to solve the problems.


solventless composite coating

Poor Coating Performance

1. The pressure of the transfer roller is not enough.

2. Mechanical brake adjustment error of transfer roller.

3. The coating roller is not clean well.

4. The poor finish of the glue pressure roller, the transfer roller, or the composite roller.

Poor Coating Performance Of Thin Film Edge

1. The adhesive close to the baffle does not replace for a long time, as long as it often swings the spray nozzle to maintain the adhesive fresh.

2. The coated pressure roller of the composite roller has glue or other impurities.

Uneven Section Of Rewinding

1. The glue amount is too large.

2. The cooling performance of the back film roll which is from the composite roller, is poor.

3. Tension is not suitable.

4. The flatness of the squeeze roll in the rewinding is poor.

5. The glue coating amount in the left and right sides of the film is too large and it is best to control the difference within 0.2g.

6. The paper core is not aligned with the film.

solventless lamination machine

White Spot

1. Low glue coating

There is not enough adhesive to penetrate into ink. At this time, it appears as a small and uniform spot in the entire composite film. The solutions are to appropriately increase the amount of glue and adjust the composite temperature and composite pressure.

2. The glue portion, the composite portion of the rollers have a poor surface finish. At this time, it is expressed as partial intermittent repeated spots. It can be judged by measuring the spacing of the two spots to find that which rolls have foreign matter and clean up.

3.The tension of substrate film is uneven and wrinkles before entering the composite roller, resulting in poor partial composite performance, and the bubbles will appear, the macroscopic manifestation is a white spot. The solution is to adjust the deflection roller and keep the film neat before entering the composite roller. The tension can be appropriately adjusted or replace film.

4.The pressure of the composite portion of the glue portion is not properly set.

5. The solubility of the ink and adhesive is not good, white spots will occur at no adhesive penetrated ink, and the suitable adhesive or ink should be replaced.

Knife Line

The main reason is that the coating units are not cleaned up. At this point, the coating unit should be downtown, or the transfer roller is changed, and the blanket is eliminated.

Poor Drying Of Adhesive

1. The adhesive is not configured in accordance with the correct matching requirements.

2. The adhesive has not been working.

3. Mixed glue contains moisture content or a large amount of ethyl acetate.

Composite Membrane Bubble

1. Since the material is not smooth and the ink particles are thick, the glue coating is insufficient. It should use high-quality materials or increase coating.

2. CO2 generated in curing cannot form in a film which has a good barrier property, mainly due to the use of a single-component solventless. So it should use a two-component adhesive.

3. The surface wettability is poor. It should increase the surface wetting tension of the material and improve the wettability of the adhesive.

4. Transfer roller is attached with foreign matter or scars and should be scrapped with bamboo pieces.

Poor Adhesion

1. The adhesive coating is too much, and the Internal curing of adhesive is slow.

2. When using a single-component adhesive, the humidification moisture content is insufficient.

3. The amount of coating is too small and the infiltration of the surface is incomplete.

4. Poor solubility of the ink and the adhesive, such as using polyamide ink.

Summary

The article introduces the common problems that occur in the solvent-free composite and the effective solutions. Adopting the solutions can greatly improve the work efficiency of the solventless laminator.