GCX film is a new type of adhesive surface material that Avery Dennison introduced to the global label industry in 2006. Due to the special properties of the product, the material was immediately accepted by printers and end-users as soon as it entered the market. Currently, among North American and European users, GCX film has become one of the preferred materials for printing process film adhesive labels. In the following article, a brief introduction to GCX materials is given in terms of the structure of the material, printing process characteristics and applications.
First, the basic structure
GCX film is made of polyethylene (PE) and polypropylene (BOPP) resin after a certain proportion of mixing, uniaxial stretching after co-extrusion, belonging to poly-hydrocarbon materials, manufacturing principle shown in Figure 1. The GCX is structurally a three-layer co-extrusion with print, intermediate, and bottom layers.
Printing layer
The printing surface is a haze-like matt effect, and the principle of this effect is that the film is uniaxially stretched to a certain degree of deformation, and the surface forms tiny, uniform holes or wrinkles. These holes or wrinkles have a haze or matt effect due to their different reflectances.
Another effect of these pores or wrinkles is to increase the wettability of the film surface to the ink. No matter which type of ink, whether it is a thin ink layer or a thick ink layer, whether it is dot printing or solid printing, the ink can be easily combined with the surface of the material, and the color characteristics of the graphic and text can be fully reflected. If printed after online corona treatment, the printing properties of the film surface will also improve.
The printed layer is composed of two types of components; the hardened part of the crystal provides the heat resistance of the material, the resistance to die-cutting impact and the retention of tensile strength, while the other part is a soft filled part, making the surface suitable for various printing Processing technology, whether it is UV ink or water-based ink, or hot stamping, cold stamping or thermal transfer printing, can achieve the best results.
2. Middle layer
The middle layer is the supporting part of the material, with a very hard resin layer, used to maintain the tensile strength and hardness of the overall material, so that the material does not shrink in the machine direction during printing and labeling, does not deform, and remains firm, when die-cutting Easy to break, making printing positioning, die cutting and labeling applications easier.
At the same time, the middle layer also has a portion of a soft resin that acts as a buffer or linker to bond with the crystallized resin. The role of the buffer is to maintain a certain degree of softness of the intermediate layer. The role of the connecting agent is to make the intermediate layer have a good connection with the printed layer and the bottom layer, making it an integral body. At the same time, the soft part of the resin can also increase the overall material's anti-friction strength and improve the material's die-cutting properties in the vertical machine direction.
3. Ground floor
The bottom layer has two functions; one is that there is a good chemical connection with the adhesive, so that the adhesive is evenly coated on the surface, does not shrink, does not foam, and does not fall off during application. Another role is to cooperate with or assist the intermediate layer to maintain the hardness and tensile strength of the overall material, so that the material has good die-cutting and labeling properties after printing.
Therefore, the composition of the underlying material is also mostly composed of crystallized, hard resin.
Second, the characteristics of the material
Since the GCX material is formed by heating and melting and co-extruding the PE and BOPP resin, it also has the dual characteristics of PE and BOPP materials.
1. Visual effects before and after printing
GCX in the original state of the material is a matt spray effect, as mentioned earlier, this is due to the material after the tensile deformation, caused by holes or wrinkles. After the haze-like material is screen-printed, it can be applied directly to the surface of the matt, pearlescent bottle without glazing. At this time, the gloss of the GCX surface is almost the same as the surface of the bottle body. In order to pursue this effect, some foreign products often use labels that are not painted on the surface of the material.
However, in order to protect the ink layer in more cases, the UV surface coating method is generally applied to the entire surface of the ink layer. If customers continue to want a matt finish on the label surface, matte UV coatings can be applied directly. If the customer wishes to have a bright light effect, the material will immediately change in nature after using the bright gloss coating, and the surface of the haze-like effect will become a light and almost transparent material.
What is the reason for this? At this time, transparent varnish fills the pores or wrinkles on the surface of the material to make the reflectance uniform and form a mirror effect. At the same time the resin in the GCX material formula is nearly transparent, so the material looks almost transparent. Using a metaphor; like a transparent frosted glass, usually see the haze, but after the surface is poured with water, the glass becomes fully transparent glass.
Figure 3 shows the transparency of transparent GCX materials before and after lamination or lamination compared with other materials. It can be clearly seen that prior to the GCX polishing, the degree of pressure atomization is stronger than that of the transparent PE material, and the gloss after the GCX is higher than that of the PE and is close to the BOPP material.
With this feature of GCX material, customers can obtain two appearance effects with the same material - bright and matt, with two different styles of labels and get two choices.
2. Die-cutting properties
The matt spray surface of the GCX material is suitable for printing and hot stamping of various printing methods. The porous surface makes the ink easy to level, whether it is the screen printing of a thick ink layer or the lithography of a thin ink layer. The on-line corona after printing can greatly increase the firmness of the ink layer, so we recommend on-line corona treatment when printing.
The uniaxially-stretched GCX material has a strong tensile strength in the machine direction because the molecular lattice in the material has been deformed and solidified. This material structure does not change in speed or drying temperature during the printing process. It will cause the deformation of the material in the machine direction, so the printing overprint is accurate and the precision is high.
As previously mentioned; GCX material contains some hard BOPP resin, and according to different needs in different proportions in the printing layer, the middle layer and the bottom layer. With this structure, the die-cutting pressure can be reduced appropriately when die-cutting, and the blade can smoothly cut the surface layer, pass through the hard middle layer, and finally stop after cutting off the bottom layer.
Due to the good fracture characteristics of the material, there is no phenomenon that the surface material is not cut through and the bottom paper is cracked. According to the experience of the American CCL label printing plant, the die cutting pressure after the use of GCX is reduced from 55 bar of the traditional film material to 14 bar.
3. Application features
Since GCX material is oriented and stretched during production, and it has a large amount of hard resin itself, it is very strong in the machine direction and can be processed into a relatively thin material compared with other materials. After labeling, labeling is very smooth when labeling automatically, even when the initial viscosity of the material is very high and the peeling force between the paper and the backing paper is higher. This is one of the most important features of GCX materials.
GCX materials are mainly used in the daily chemical industry, and many products in the daily chemical industry need to be squeezed and deformed. Therefore, when the label material is squeezed, it can be deformed along with the deformation of the bottle body without wrinkling and curling. Since GCX material is uniaxially stretched and deformed in the other direction, it can be adapted to the deformation requirements of the bottle body during extrusion. This is another feature of the GCX material.
The comparison of the elastic deformability of GCX materials with other film materials shows that the PE material has the best followability, while the BOPP has the worst following, and the GCX is somewhere in between.
Third, the scope of application of the material and the overall value
1. Application range
The GCX material has the flexibility and followability of the PE material, and is superior to the PE in the matt atomization effect and print processing adaptability. At the same time, it has the firmness and transparency of BOPP material, but it is stronger than BOPP in terms of flexibility and followability. Therefore, the GCX material is suitable for use on different types of bottles, such as various PE bottles and glass bottles, and is particularly suitable for use in transparent BOPP and PET bottles.
2. Overall value
GCX materials are extremely challenging in their overall value compared to other thin film materials;
* It is lower in cost than PE and BOPP and competitive in price.
* In terms of performance, with the advantages of both PE and BOPP, it can replace both materials at the same time.
* In terms of appearance, two types of labels can be formed through the glazing process; full transparent and matte fog labels.
* In inventory management, the reduction in stocks of inventory reserves has reduced the overall operating costs of the company.
* Good printing and processing characteristics, customers can unify equipment and equipment, optimize management.
GCX material is a new product that Avery Corporation has launched simultaneously in the world. It has a unified standard management and technical service and is a global brand. With the widespread use of international day-to-day companies, GCX self-adhesive film materials will be used in the label industry in China. Finally, we wish GCX material to bear fruit in the Chinese market and contribute to the prosperity and development of the label industry.