Common problems and solutions of BOPP precoating film
1. The product is wrinkled
(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)The surface of the rubber roller is damaged and uneven, and the rubber roller should be replaced.
(3)The pressure between the rubber roller and the heating roller is unbalanced and 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.
2. Snow spots appear on the product
(1)The pressure of the rubber roller is not enough, so the pressure should be increased appropriately.
(2)The glue on the precoating film is not completely melted, which can be solved by the following methods.
①Properly increase the film covering temperature.
②Increase the contact area between the film and the heating roller to increase the melting degree of the adhesive on the film under the same speed.
③Reduce the film covering speed.
(3)Dust and impurities on the gluing surface of the precoated film shall be removed in time.
3. Poor adhesion and film peeling
(1)If the pre-coating film exceeds the shelf life, replace it with a new one.
(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 printed matter is covered with film.
(3)Low pressure, fast speed and low temperature of film covering can be appropriately increased to reduce the film covering speed and increase the film covering temperature
4. Product curl after slitting
(1)If the membrane tension is too large, which causes the membrane to expand and deform, the membrane tensioning screw should be adjusted.
(2)The winding tension is large, which makes the film and paper deform at the same time. The winding tension mechanism should be adjusted.
(3)The ambient humidity is high, so the humidity of the production workshop should be controlled at about 60%.
(4)The drying time is short. The drying time should be appropriately extended. After the film covering product is completely dried and cooled on the take-up roll, the film can be cut and cut.
That is, the common point of blistering and film stripping of the film-coated products processed by the gluing wet composite process is that the film breaks away from the substrate of paper and printing, and damages the compactness and smoothness of the paper/plastic composite.
To improve the wear resistance of biaxially oriented polypropylene membrane (BOPP membrane), a novel polypropylene surface modification coating with good transparency and wear resistance was prepared by sol-gel method, using silane coupling agent (KH550), aluminum sec butanol (ASB) and ethyl orthosilicate (TEOS) as precursors, solid acid (p-toluene sulfonic acid) as catalyst
The printing and film are combined by professional laminating equipment to form a paper-plastic product. This technology is called lamination. The surface of the printed matter coated with film is brighter and smoother, the pattern is more bright, and the performance of wear resistance, folding resistance, tensile resistance, moisture resistance, chemical corrosion resistance and other properties are also enhanced. Even some apparent defects in the printing process can be largely compensated. Therefore, not only the service life is extended, but also the beauty of the product is greatly improved. Since the film coating technology was born in the 1950s, the film coating technology has experienced three important development stages:solvent-based coating technology, water-soluble coating technology, and precoating technology.
Precoating film refers to the process of laminating plastic film with paper print after pre-gluing and rewinding. The precoating film structure is composed of substrate and adhesive layer. According to different substrates, the precoating film can be divided into BOPP precoating film, BOPET precoating film and BOPA precoating film. The adhesive layer is mainly EVA hot melt adhesive and LDPE hot melt adhesive. Downstream mainly applies to the packaging of books, food, medicine, daily necessities and other products in the field of industrial printing, digital printing, card certification, anti-counterfeiting, commercial advertising and construction materials in the special products market in the field of commercial printing.