2019年8月23日星期五

Factors affecting the quality of the film lamination

01
Print ink layer condition
Refers to paper properties, ink properties, ink layer thickness, graphic area and printed graphic density. [ Film Lamination Machine ] When the printed ink layer is thick and the image area is large, many paper fiber capillary pores are blocked, which hinders the penetration and diffusion of the adhesive, making the printed matter and the plastic film difficult to adhere, and delamination, foaming and the like are prone to occur.



02
environment humidity
Between the adhesive and the plastic film and the printed matter, as the relative humidity of the air changes changed the water content. Humidity-sensitive prints can cause internal stresses due to dimensional changes. For example, the longitudinal expansion ratio of the printed matter is 0.5%, and the longitudinal heat shrinkage of the BOPP film is 4%. If the water absorption of the printed matter is too large and the elongation occurs, and the internal stress is caused between the heat shrinkage of the film, the film product may be curled, wrinkled, and bonded. [ Fully Automatic Lamination Machine ] Not strong. In addition, in a high humidity environment, the equilibrium moisture value of the printed matter will also change, and a large amount of moisture absorbed from the air medium will be released from the surface during the hot pressing compounding process, stagnating at the bonding interface, and partially forming a non-adhesive bond. phenomenon. Moreover, the change in the equilibrium moisture value of the printed matter (moisture from the air medium or dehumidification into the air medium) occurs mostly at the edge of the printed matter, so that it forms a ruffled edge or a tight edge, and is not easily formed well with the film in the hot press composite. [ Automatic Lamination Machine ] The wrinkles are caused by the bonding, so that the production cannot be carried out smoothly.



03
temperature control
Heating can soften the film and bond the paper to the plastic film. However, the temperature is too high, the film is easy to break, which seriously affects the quality of the product. Therefore, measures such as fan cooling and turning off the heating wire should be adopted.

2019年8月21日星期三

How large is the lamination strength ?

Refers to the bond fastness between the plastic film and the paper (board) print in the film product. The size depends on the adhesion between the plastic film, the paper (board) print and the adhesive (or hot melt adhesive). [ film lamination machine ] When laminating, the adhesion is mainly derived from the mechanical bonding force and physico-chemical bonding between the plastic film, the paper (plate) printing article and the adhesive (or hot melt adhesive).





               Fully Automatic Thermal Film Laminating Machine



The key to film fastness is the affinity of the glue to the print (ink and substrate). As a film coating industry, printing inks are not selectable, that is, only the film that is suitable for the ink market is the only choice, so as a pre-coating film, it can only be regarded as high quality by adapting to the performance of all inks.[ lamination machine manufacturer ]. The composite strength of the coated product is affected by the process parameters in the film production process, such as the temperature, pressure, speed of the coating process, the coating condition of the adhesive, the film tension and environmental factors. At the same time, it is affected by the printing process, such as the surface state of the printed product formed after printing, such as the thickness of the ink layer, the area and distribution of the image, the characteristics of the ink, the use of the thinner, the use of dusting, and the drying of the ink layer.

2019年8月16日星期五

Commonly Used Lamination Film Are ?

Commonly used plastic films are: polyvinyl chloride (PVC), polypropylene (BOPP) and polyester (PET) films. Among them, BOPP film (15-20pm) is flexible, non-toxic, high transparency and low price, and is an ideal composite material in the film coating process. [ thermal lamination machine ]


Depending on the properties of the film itself and the purpose of use, the thickness of the film is preferably between 0.01 and 0.02 mm. It must be treated by corona or other methods. The surface tension of the treated surface should be 4 Pa, so as to have better wettability and adhesion. The corona treatment surface should be uniform and the transparency should be as high as possible to ensure the best definition of the covered print. [ thermal laminator ] The transmittance of PET is generally 88-90%, and the transmittance of other films is usually between 92-93%. The film needs to have good light resistance, is not easy to change color under long-time illumination, and the geometric size is stable.


Since the film is in contact with a solvent, a binder, an ink, etc., it must have a certain chemical stability. The appearance of the film surface should be flat, without unevenness and wrinkles, and the film is required to have no bubbles, shrinkage holes, pinholes and pitting. Due to the limited adjustment ability of the laminating machine, it is also required that the rewinding is neat and the two sides are elastic and uniform to ensure uniform coating.[ lamination machine manufacturer ] Of course, the cost is low.

2019年8月15日星期四

Classification of Film Lamination

Coating film
That is, when the coating film process is performed, the adhesive is applied to the film, and then hot pressed.
This is also the current popular processing method.


Pre-coated film
This process greatly simplifies lamination because the laminating equipment does not require a binder to heat the drying system.
The program is very convenient to operate, can be used with the start-up, has great production flexibility, no solvent smell, no environmental pollution, more importantly, it can completely avoid bubbles, delamination and other faults, and its finished product has high transparency and wide application prospects and promotional value. [ water based lamination machine ]
The pre-coated film structure is composed of a substrate and a glue layer. The substrate is usually a PET film and a BOPP film. From the viewpoint of material cost and processing technology, most of the pre-coated film substrates are made of BOPP film and have a thickness of 12-20 micrometers. The thickness is 5-15 microns. According to different processing equipment and process conditions, different thicknesses of glue layer are selected, and the glue layer is divided into hot melt adhesive and organic polymer low temperature resin plate. [ film lamination machine ] The difference between the two is that the hot melt adhesive is made by blending and modifying several materials of the main adhesive resin, the tackifier and the modifier, and the organic polymer resin is a single polymer low temperature copolymer.
Due to limitations in technology, production equipment, and raw materials, pre-coated films (mostly hot melt adhesives) produced by domestic equipment still have quality defects. Since the production process is a process similar to that of the coating film, the colloid is dissolved in an organic solvent, and the rubber is roll coated on the substrate film by a concave anilox roll, so that the solvent volatilization is insufficient, and the odor is generated during operation. After the film is coated, the solvent evaporates and the surface is easy to foam. At the same time, since the hot melt adhesive is blended by several kinds of polymer materials, the temperature control is not good, which will cause degradation and cross-linking of the high molecular polymer in the hot melt adhesive, and the surface of the film is poor.[ lamination machine manufacturer ]Some pre-coated film colloids easily adhere to the outer surface of the substrate, resulting in poor winding. Since the adhesive layer is thin and the surface is not activated, defects such as insufficient adhesion to the printed matter are likely to occur. Since the hot melt adhesive is composed of several kinds of materials, the transparency after coating is significantly worse than that of the low temperature pure resin type pre-coated film.


Water-based coating
It is a method of processing the surface of printed products to improve the gloss, strength and aesthetic effect of the surface of the printed products. To measure the quality of the film, it is also necessary to examine its brightness, strength, and adhesion. The water-based wet film is favored by customers because of its high strength, easy recycling and non-polluting properties.


Curved film
It is a new transfer technology that can cope with complex workpieces and is suitable for different materials. It also greatly increases the added value of products due to vivid patterns and vivid colors. This technology is a special chemical treatment film, after printing a certain color pattern, it is sent to the surface of the water, using water pressure to write the pattern evenly on the surface of the product, while the coated film is automatically dissolved, washed and baked. After drying, a layer of transparent protective coating is applied, and the product has a completely different visual effect.
The coating process can be divided into cold (cold pressure) coating, hot (heating) coating and liquid coating according to the heat, pressure and material.[ automatic lamination machine ] Thermal coating technology refers to heating and pre-coating the adhesive on the diaphragm, through which the film is bonded to the printed product; while the cold coating is pressed, directly bonding the film to the printed product by the adhesive. Together. Both methods can produce various special films such as UV protective film, waterproof or anti-friction film. Recently, there has also been a new technology called "liquid film". Simply use a brush, a net gun, a roller or a special laminator to apply a film directly on the surface of the product. Although the technical operation is simple and the price is low, it is still not mature.

2019年8月13日星期二

Brief Introduction of Industrial Film Laminating

The film coating is a process in which a plastic film is coated with a binder, and the paper printed product is heated and pressurized to bond it together to form a paper-plastic composite product. The film-coated printed product has a thin and transparent plastic film on the surface, and the surface is smoother and brighter, thereby improving the gloss and fastness of the printed product. The color of the graphic is more vivid, three-dimensional, and waterproof. Anti-fouling, abrasion resistance, folding resistance, chemical corrosion resistance, etc.[ Automatic Lamination Machine ]


Air bubbles caused by production processes. Mainly refers to the control of some process parameters, including composite pressure, coating temperature and composite temperature. If the composite pressure is too low, the rubber roller pressure should be increased appropriately.[ Lamination Machine Manufacturer ] The compounding speed is too fast, and the compounding speed can be appropriately lowered, or the temperature of the rubberizing roller can be increased to increase the fluidity of the adhesive. Air bubbles on the surface of the film caused by dust and impurities should improve the environmental sanitation of the production workshop.

2019年8月7日星期三

Why air bubbles occurred during the lamination ?

The viscosity of the adhesive is also an important cause of air bubbles. 
[ water based lamination machine]


Generally speaking, the viscosity of the adhesive is related to the molecular weight of the adhesive, the plasticizer and the type of the diluent, and the adhesive generally has a high viscosity and a poor fluidity at normal temperature, so in order to lower the viscosity and improve the fluidity, it is required to be higher in the compounding. Insulation at temperature. The higher the temperature of the two-component adhesive, the shorter the mixing and storage time, and the larger the ratio of the main agent and the curing agent, the greater the viscosity of the adhesive, the more unfavorable the formation of bubbles, and the more easily the bubbles are formed. Bubbles of the same size, low-viscosity glue can be eliminated, and high-viscosity glue may not work because the high-viscosity gel has a large molecular weight and poor leveling.[sheet lamination machine]

2019年8月3日星期六

Why Bubble Appeared during the lamination process?

The cause of bubble formation:

Different types of composite substrates have different physical properties (such as gas permeability), and have a great relationship with the formation of composite film bubbles. Generally speaking, a substrate with good gas permeability (such as BOPP, CPP, CPE, LDPE) or a composite substrate with poor gas permeability (such as PVDC, BOPA) and another composite substrate with good gas permeability are compounded. It is not easy to generate bubbles. [ roll to roll lamination machine]

However, if the two substrates have poor gas permeability, when they are compounded, bubbles are easily generated, such as PVDC and BOPA. This is because the gas permeability of the two composite substrates is relatively poor, and the adhesive inevitably mixes a small amount of air on the compounding system. At the same time, the isocyanate adhesive itself is cross-linked and solidified during the curing stage of the composite film, and also produces gaseous by-products such as carbon dioxide (CO2). In this way, a large number of tiny bubbles are generated, thereby affecting the apparent quality of the composite film. [ film lamination machine]


At the same time, in order to make the composite substrate have a certain surface tension, the surface properties of the substrate must be treated, such as corona treatment, to improve the wettability of the surface of the composite substrate and improve the roughness, but the roughness exceeds At certain limits, it is difficult to be filled with viscous glue. Thus, large and small bubbles are formed between these minute engaging faces.

Type of printing

Classification of printing methods based on the relative position of the graphic and non-graphic areas on the plate (1) Letterpress printi...