Common failure causes and solutions of film coveri

2022-09-21
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Common failure causes and solutions of post press lamination

lamination is a process in post press processing, and various quality problems often occur in lamination, It directly affects ink "> to meet the arrival of a new era in the field of materials. The coating quality of printing products causes unnecessary losses and waste, which must be treated seriously.

1. Blistering on the surface of coated products

phenomenon and reasons:

(1) The humidity of the paper is high, and the printed products are coated without drying. When the products are gradually dried after coating, the water vapor in the paper evaporates, and plaques or bubbles form between the surface of the paper print and the plastic film

(2) the paper printed matter has dusting and dust after printing, or the surface of the plastic film has dust, impurities and stains

(3) too much anti sticking agent and quick drying agent are added to the ink during paper printing

(4) the adhesive solution of the film coating is too thick or too thin, and the adhesive layer is too thin or too thick

(5) the adhesive liquid coated by the coater is uneven or the adhesive is aging

treatment method:

(1) dry the paper and printed matter, and adjust the temperature and humidity in the car room

(2) clean the dust and impurities on the surface of paper and plastic film

(3) during paper printing, control the addition and measurement of anti adhesion agent and quick drying agent in the ink

(4) strictly control the ratio of adhesive and thinner, and adjust the thickness of adhesive layer and the concentration of adhesive liquid

(5) adjust the gap between the two rollers of the coater to make it uniform, and replace the aged adhesive liquid

2. Wrinkling phenomenon and causes of paper printed matter when laminating:

(1) paper printed matter is subject to high humidity or high ambient temperature and humidity in the production site, resulting in tight edges of printed matter or the formation of wavy ruffles

(2) uneven roller pressure or uneven guide roller gap during film covering, resulting in uneven paper film covering and wrinkling

(3) when the conveyor belt is conveying paper, the paper printed matter is skewed and irregular

treatment method:

(1) strictly control the temperature and humidity changes in the workshop, knock the deformed printed paper flat, and then carry out the film covering operation

(2) adjust the covering pressure between the rubber roller and the heating roller of the pressing roller and the gap between the guide rollers

(3) adjust the guide roller conveyor belt and side rules, and pay attention to the paper feeding moment

3. Wrinkling of plastic film

phenomenon and causes:

(1) the temperature of the heating drum or the drying channel is too high when laminating and pressing, and the plastic film softens and deforms, causing wrinkling of the film under the pressing action of the heating drum

(2) the film tension is too tight during laminating operation, causing vertical or oblique wrinkling of the film

(3) the film covering speed is too fast, and the adhesive liquid is not completely dry, causing the film to wrinkle

treatment method:

(1) adjust the temperature of the hot pressing roller or the temperature of the drying channel to make it meet the conditions of hot pressing

(2) adjust the pulling force of plastic film, adjust the stretching roll, loosen the film pressure, and press the film after flattening

(3) reduce the speed of the main machine of the laminating machine, slow down the transmission time, and press the plastic film with the paper print when the adhesive liquid is completely dry

4. Curling phenomenon and causes during processing of film coated products:

(1) paper prints are damp and deformed

(2) the climate is humid, and the environmental temperature and humidity of the production site are high

(3) the temperature of the heating drum of the laminating roller is high, and the laminating pressure between the rubber drum of the pressing roller and the heating drum is large

(4) the tension of plastic film is too tight

treatment method:

(1) press and flatten the coated product before slitting

(2) control the temperature and humidity of the production site environment

(3) appropriately reduce the temperature of the heating drum of the low-pressure closing roll and adjust the covering pressure between the rubber drum and the heating drum cooled by the sudden heat of the pressing roll

(4) adjust the traction force of plastic film

5. The paper and plastic are not bonded firmly after being covered, and the paper and plastic are naturally separated during post-processing.

phenomenon and reasons:

(1) the ink layer of paper prints that need to be covered with film is not dry

(2) the pressure of paper plastic coating is too small, the coating speed is fast, and the coating temperature is low

treatment method:

(1) extend the drying time of paper and printed matter

(2) appropriately increase the pressure of lamination, adjust the speed of lamination and the temperature of lamination

6. The surface of the printed matter turns white after film coating

according to the data, the phenomenon and causes:

(1) the temperature and humidity of the environment of the film coating site is too high, and the outer layer of the paper printed matter after film coating is dry, but the inner layer is still not dry

(2) there is water vapor between the paper print and the plastic film coating layer after coating

treatment method:

strictly control the temperature and humidity of the production site environment

to sum up, there are many reasons that affect the quality of coated products. It is a high-tech job to achieve the ideal and best effect of paper printing after coating. We should strictly process, standardize the operation, analyze the reasons, find out the main problems, and solve them according to the specific situation. Only in this way can we reduce waste, continuously improve the quality of coated products and meet the needs of the market

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