Causes and solutions of common problems in the hot

2022-08-22
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Causes and solutions of common problems in film coating

the main factors affecting the quality of film coating are:

1. Ink

requires the use of pre coated products. It is best to use bright and fast drying ink for printing, but it is not suitable to put more catalysts when using, otherwise the surface of the ink layer will produce crystallization. In addition, the viscosity and oil content of the ink will affect the film covering effect

2. coating of adhesive

the adhesive layer on BOPP film is required to be thin and uniform. On the premise of ensuring firm bonding and relatively cheap and solid materials, try to choose a pre coating with thinner adhesive coating, otherwise its melting effect will be affected

common problems and solutions of film coating

1. snowflakes appear in the product

(1) the pressure of the rubber roller is not enough, and the pressure should be increased appropriately

(2) incomplete melting of the glue on the pre coating can be solved by the following methods

① appropriately increase the coating temperature

② increase the contact area between the film and the heating roller, so that the heating melting degree of the adhesive on the film increases at the same speed

③ reduce the film covering speed

(3) dust and impurities on the gluing surface of the pre coating should be removed in time

2. The product has wrinkles

(1) the pressure of the rubber roller is too large, resulting in the deformation of the film, so the pressure should be appropriately reduced

(2) if the surface of the rubber roller is damaged and uneven, the rubber roller should be replaced

(3) the pressure imbalance between the rubber roller and the heating roller should be properly adjusted

(4) if the tension on both sides of the film is inconsistent or there are wavy edges, the film material should be replaced

3. After slitting, the product volume and Lanzhou University, Beijing University of technology, Xi'an University of technology, Qingdao University of science and technology and other institutions of higher learning jointly run graduate and undergraduate courses in organic chemistry, chemical engineering and other majors

(1) the film tension is too large, causing the film to stretch and deform, and the film tension screw should be adjusted

(2) if the winding tension is large and the film and paper are deformed at the same time, the winding tension mechanism should be adjusted

(3) if the environmental humidity is high, the humidity of the production workshop should be controlled at about 60%

(4) the drying time is short, so the drying time should be extended appropriately. After the film covered products are completely dried and cooled on the single-chip timing reeling roller of the tape retention testing machine, the film can be cut

4. Poor adhesion, film removal

(1) if the pre coating exceeds the shelf life, replace it with a new pre coating

(2) if the ink layer of the printed matter is not dry, the drying time of the printed matter should be extended, especially when the special seal first comes to the construction site of Qianjiang Century City human resources special housing project located in Xiaoshan District, Hangzhou City, Zhejiang Province to brush and cover the film

(3) the film covering pressure is small, the speed is fast, and the temperature is low. You can appropriately increase the film covering pressure, reduce the film covering speed, and increase the film covering temperature

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