Paper products, packaging can not be separated, and these packaging materials after the film, having a better toughness, dirt and dust better, so in the packaging industry, packaging material covered is the common printing paper print after processing one process.
Coated plastic film is coated with adhesive after the paper printed with the heated, pressurized sticking together to form the unity of paper and plastic products.
Coating material
After coating printed, due to the surface more than a layer of thin, transparent plastic film, the surface is more smooth and shining, not only improves print gloss and fastness, extending the life of the print, but also play a waterproof plastic film, Protective effects of anti-fouling, abrasion, folding, resistance to chemical corrosion. If the transparent light film coating, coating products, printing graphic color more vivid, rich three-dimensional, especially for commodities such as green food packaging, can cause people's appetite and desire for consumption. If matte film coating, coating products will give consumers a noble, elegant feel. Thus, after the film packaging printed packaging can significantly improve the quality and added value. Currently, a common packaging film products are cardboard boxes, cartons, bags, fertilizer bags, seed bags, self-adhesive labels.
Coated paper print process according to the coating process can be divided into three categories: dry coating method, a wet coating method and the pre-coat coating method.
Dry coating method is currently the most commonly used coating method, which is on a plastic film coated with a layer of adhesive and adhesive solvent after laminating machine drying bake removed and dried and evaporated in the heat again depressed state paper print sticky synthetic resin coated products.
A wet coating method is in a plastic film coated on the surface layer of adhesive, in the adhesive is dry situation, and paper print sticky synthetic resin coated products through nip rolls. Since the advent of water-based laminating machine, water-based coating technology has been promoting the application of which has a wet coating process is simple, adhesives with less damage to the environment does not contain organic solvents, film prints with high strength, high quality, easy recovery and so inseparable. At present, the coating process more and more domestic packaging manufacturers of all ages, has been widely used for gift box and bag packaging and the like.
Precoated coating method is a coating factory direct purchase pre-coated with adhesive plastic film, if desired film, the film and the paper printed together on a hot film equipment, complete coating process. Precoated coating process began in the 1990s. The low temperature hot melt adhesive or resin is uniformly coated on a substrate film by special equipment designed in accordance with the quantitative, laminating film is obtained. Pre-coat coating method eliminates the need for adhesive formulations, coating and drying step of the process, the entire coating process can be completed within a few seconds, no pollution to the environment, no fire hazard, do not need cleaning coating plastic equipment. At present, the technology has been used in pharmaceuticals, food packaging.
1, the concept and the role of coating
Film called "a plastic", "lamination", "film" and one of the main part of the process of finishing. Refers to the adhesive-coated on a transparent plastic film and paper printed with the composite, and then heated, pressurized so that bonded together to form the unity of paper and plastic processing technology.
After coating printed, due to the surface more than a layer of thin, transparent plastic film, the surface is more smooth and shining, thereby improving the print gloss and fastness, extending the life of the print, but also play a waterproof plastic film, Protective effects of anti-fouling, abrasion, folding, resistance to chemical corrosion.
2, film classification process
1) based on the use of different raw materials and equipment, the coating process can be divided into: the two kinds of film coating process and the pre-coat coating process.
That is coated with a thin film coating process the scene is coated, the adhesive used are generally two kinds of solvent-based and emulsions, and is used with the distribution. That is when the coating film process operation on the first adhesive film coating, then after pressing the paper composite.
Thermal lamination process used for pre-coating film is good, adhesives used are generally hot melt and solvent evaporation type two. This process is due to the adhesive coating equipment without heat drying system, greatly simplifying the coating process, and the operation is flexible, can be used with the boot, can reduce air bubbles, delamination failures produced, the finished product transparency, and has broad prospect and popularization value.
2) coating process can also be in accordance with the hot and cold, pressure conditions and material is divided into: cold (cold) coating, thermal (hot live) coating and liquid coating and other means.
Thermal coating technology refers to the pre-coated adhesive film heat activated adhesive together with the diaphragm through which the printed materials; and the cold is covered by pressure, depend directly on the film and adhesive printed materials together. Both methods can produce UV protective film, waterproof or anti-friction film all kinds of special films. More recently, the emergence of a new technology, called "liquid coating" method. It is a transparent liquid with a brush, sprayer, roller or a special laminating machine directly on the surface of the product brush on a film. Technical operations, although simple, the price is also low, but is not yet mature.
