The hottest precoating process

2022-08-13
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Pre coating and film covering process

the pre coating and film covering operation is to use the plastic film that has been pre coated with adhesive. As long as hot pressing is carried out, the film covering can be completed, so it is also called dry film covering

the pre coating process is that the professional manufacturers engaged in the production of pre coating film use more reasonable equipment to pre coat the hot melt adhesive on BOPP and other substrate films in a quantitative and uniform manner according to the design. After drying, winding and packaging, the hot melt adhesive pre coating film is made and sold as a product. The post press processing enterprises carry out hot pressing on the coating equipment without adhesive coating device to complete the coating processing of printed matter

the pre coating process is an advanced post press processing technology in the 1990s. During film covering, the process flow of adhesive preparation, coating, drying and so on is omitted, there is no solvent swelling on the film and decomposition of the ink, and there will be no secondary softening of the adhesive, loss of adhesion and swelling on the film, resulting in foaming and film removal. In addition, the selection of hot melt adhesive materials and the design and control of quantitative coating have a set of extremely strict scientific analysis, calculation, monitoring and adjustment methods, which basically meet the physical and chemical requirements of bonding and film covering reprocessing (folding, necking, pasting, indentation, die cutting, etc.) with printed matter made of various papers and inks. The requirements for the drying degree of ink are not strict. The whole compounding process is completed in a few seconds, without cleaning the gluing mechanism and other components. There is no poison, air pollution and fire hazards

classification of hot melt adhesive pre coating

there are four classification methods of hot melt adhesive pre coating

① according to the precoating method of hot melt adhesive, it is divided into three categories:

a. extrusion spray precoating. The solid hot melt adhesive becomes liquid through the high-pressure temperature regulation of special extrusion equipment. After controlling the quantity, it is sprayed and attached to the film surface

b. melt transfer type pre coating. The solid hot melt adhesive changes into viscous flow state through the heating device of the coater, and completes the coating of film surface transfer on the elastic working interface

c. solvent printing type pre coating solid with liquid crystal display thermosol through the action of solvent, the sample should be cut from the test piece with uniform thickness, softened into thin paste, and then transferred to the film

the pre coating film produced by extrusion spray and melt transfer is solvent-free, non-toxic and tasteless, and the solid content of the adhesive layer is 100%. Good transparency, strong cohesion and long shelf life

the pre coated adhesive layer produced by solvent printing contains the latter, which becomes a roadblock to reduce production capacity. There is a certain amount of organic solvent, which smells and makes a noise when used, and feels a little sticky. The transparency is poor, the adhesion is weak, and when folding or die cutting, indentation, it is easy to produce hollow creases of the film at the stressed part, which is not resistant to sunlight and hot wind

② according to the film substrate, it is divided into three categories:

pp (double-sided stretched polypropylene) pre coating

t (polyester) pre coating

p (cast polypropylene) pre coating

③ according to the light transmittance of the film, it is divided into three categories:

a.1000mm level has 1000, 1080, 1100, 1200, a total of four kinds

b.800mm level has 850, 870, 880, a total of 3

c.700mm level has 700, 760, 770, 780, a total of 4 kinds

d.600mm level has 610, 620, 650, 690, a total of 4 kinds

e.500mm level has 9 kinds, including 500, 510, 520, 530, 540, 560, 570, 580, 590

f.400mm level has 410, 420, 430, 440, 450, 460, 470, a total of 7 kinds

g.there are 10 kinds of 300, 310, 320, 330, 340, 350, 360, 370, 380, 390 in 300mm class

h.200mm has 200 and 270, a total of 2 kinds

American GBC company is the world's largest manufacturer of film coating consumables and equipment, and the only professional manufacturer specializing in pre coating materials and equipment in the world. It has the world's most advanced film coating consumables and equipment production technology, and its products have been sold in dozens of countries and regions around the world. Beijing comfield printing equipment Co., Ltd. introduced the American GBC pre coated commercial film into the Chinese market and built the first domestic and second world pre coated film production base

Kangde GBC pre coated commercial film has the following characteristics: it has the ability to modify the large field printed matter after powder spraying, and it does not need to remove the powder manually; The pre coating has strong adhesion, and will not produce bubbles, folds and film failure in production; The coated surface can be processed by post processes such as local glazing and bronzing; The film covering process does not produce any polluting gases and substances

precoating laminating machine

precoating laminating machine is a special equipment that combines printed matter with precoated plastic film. Its main structure is shown in the figure. It is composed of four parts: film unwinding, automatic input of printed matter, hot pressing compounding, and automatic winding. Compared with the instant coating laminating machine, it does not need adhesive coating and drying parts, so it has compact structure, small volume, low cost, simple operation, start-up with use Production flexibility and high efficiency

the combination of pre coating and paper printing can only be achieved by hot pressing. It is suitable for all kinds of laminating machines, laminating machines and plastic sealing machines with hot pressing function. That is, the bridge type combined laminating machine of gluing wet work composite process does not need to make any changes, and it can be completely used for precoating

the operation procedure of pre coating includes five steps: discharging, starting, transporting printed matter, winding and slitting

① put the pre coating film through the feeding rod and place it on the feeding shaft seat. Pass through the straight flattening roll and the bow flattening roll and level them

② start the host and receipt device, and rotate the receipt drum to raise the temperature, so as to keep the heat uniform; The pressure rise makes the pressure rubber roller contact with the receipt drum and rotate for pre temperature

③ transport the printed matter, sort out the surface state of the printed matter, adjust the regular board, and automatically or manually continue the paper

④ winding start the winding device, wind the composite on the winding shaft, and control the appropriate tension

⑤ slitting cut and store the integrated composite products as a single sheet of paper, inspect the quality and count the quantity

as long as the three technical parameters of temperature, pressure and speed are well mastered, the normal film covering production can be basically guaranteed

temperature (actual temperature on the surface of the receipt roller): 85 ~ 95 ℃ for general products; Special products (thick ink printing layer, deep color, high paper weight, high water content) 90 ~ 105 ℃. Pressure: 10 ~ 15MPa; Speed: (print running speed) 8 ~ 12m/min. (China Packaging News)

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