what Sticker labels for UV printing!
With the improvement of quality of life, personalized needs more and more fine, the product packaging and personalization is getting higher and higher, this time stickers label stickers of the market usage is getting bigger! Here we talk about what Sticker labels for UV printing!
Before we talk about the printing process and the processing method of the self-adhesive label, we must first understand what is the printing of the self-adhesive label, and it is different from the traditional label printing. Self-adhesive labels are also called self-adhesive labels, timely stickers, stickers, pressure-sensitive paper, etc., is a paper, film or special materials for the fabric, coated with adhesive on the back to silicon protective paper for the end of a paper Composite materials, and by printing, die cutting and other processing products become a label. Application only need to peel off from the end of paper, gently press, you can paste the surface of a variety of substrates, labeling machine can also be used in the production line automatically labeled.
Self-adhesive label compared with the traditional label, do not brush plastic, do not paste, do not have to dipped in water, no pollution, saving labeling time, applied in a variety of occasions convenient and fast. Different fabrics, adhesives and end of the various types of labels can be applied to the general paper label can not do the material, you can say: stickers is a universal label. Self-adhesive label printing compared with the traditional printing is very different, self-adhesive labels are usually printed on the label linkage processing, multi-process once completed, such as graphic printing, die cutting, waste, cut or complex Volume and so on. That is, one end of the whole volume of the raw material input, the other end of the output of finished products. Finished products are divided into leaflets or rolls of labels, finished labels can be directly applied to the goods. So, stickers label printing process is more complex, the equipment performance and printing staff quality requirements are higher.
In the self-adhesive label printing process, we must also understand the basic structure of the adhesive material as a printed material and the functions of each part. The structure of the adhesive material from the surface point of view is composed of three parts, namely the surface material, adhesive and the end of paper, but from the manufacturing process and ensure the quality of the point of view, the adhesive material consists of seven parts:
1, surface coating
Used to change the surface characteristics of the surface material. Such as improving the surface tension, changing the color, increasing the protective layer, etc., to better accept the ink and easy to print, to prevent dirt, increase ink adhesion and prevent the purpose of printing graphics off. Surface coating is mainly used for non-absorbent materials, such as aluminum foil, aluminum paper and various types of film materials.
2, the surface material that is the surface material, is a positive acceptance of printed graphics, the back of the adhesive and eventually applied to the paste on the material.
In general, all flexible materials can be used as adhesive materials, such as commonly used paper, film, composite foil, all kinds of textiles, thin metal and rubber and so on. The type of surface material depends on the final application and the printing process. Facing to be able to adapt to printing and printing, with good ink, and have enough strength to accept a variety of processing, such as die cutting, waste, slitting, punching and labeling.
3, the bottom of the coating
Its surface coating with the same, but is coated on the back of the surface material, the main purpose of the bottom layer is:
(1) to protect the surface material, to prevent the adhesive penetration.
(2) increase the opacity of the fabric;
(3) increase the adhesion between the adhesive and the same material;
(4) to prevent the plastic surface material in the plasticizer penetrate into the adhesive, affecting its adhesive performance, resulting in decreased adhesion of the label, the label off.
The adhesive is a medium between the label material and the bonding substrate. According to its characteristics can be divided into permanent and removable two. It has a variety of recipes, suitable for different surface materials and different occasions. Adhesives are the most important ingredient in self-adhesive materials technology,
Is the key to the application of labels.
Round pressure round for all kinds of pattern label printing, especially for high-grade color network color label printing.
UV printing: In the above three printing methods, coupled with UV drying, can be printed film adhesive material.
(4) first bronzing, after printing
In the case of UV-free equipment, the use of ordinary ink, the disadvantage is the printing pattern design is limited.
(5) first printing, after the bronzing
Application of UV drying device in the device, the ink quickly after drying in the ink on the gold foil, bronzing pattern arbitrary design, free from ink restrictions, suitable for high-grade label printing, is an advanced production process.
Field light: the surface of the ink coated with a layer of varnish, the purpose is to protect the ink layer, moisture, water and improve the surface gloss, can replace the film process, using UV drying.
In the paper or film material on the membrane, the purpose is to protect the ink, waterproof, moisture, increase the label strength, increase the pattern
Three-dimensional. Fumo is divided into a base paper laminating and no backing paper, due to the latter low cost, is currently widely used. According to the requirements of the process there are two kinds of composite transparent film and matt film, the former application of more common.
Applications are not common and are mainly used for computer-printed labels. Requirements are labels on both sides of the label to drive the hole, or the application of the tag on the label, requiring the middle of the label punching for positioning and driving.
(9) die cutting
Self-adhesive label die-cutting process for the semi-cutting, that is, only cut through the surface material and keep the end of paper. Divided into two kinds of processing methods:
Such as flat die-cutting, suitable for all kinds of label printing presses, artificial plate, low cost, plate-making cycle is short, but low viscosity, suitable for short version of live printing processing. At present, almost all domestic label factory adopts flat die cutting method. Another is a circular die-cutting, the application of a round pressure round label equipment, fast, die-cutting high viscosity, suitable for long version of live, the drawback is the plate cost, long cycle. At present, domestic manufacturers of die-cutting roller are generally in foreign processing.
(10) received the paper
Can be divided into cut sheets and received paper.
2, paper-based self-adhesive label processing methods
(1) sheet of paper
Such adhesive materials in the printing method, offset 95%, embossing accounted for 2%, silk screen accounted for 2%, computer and print accounted for 1%. Sheet of paper self-adhesive label printing and ordinary print the same, the various processes in the single machine to complete, low production efficiency, high cost of consumption, but the printing quality is good. Such as the use of offset printing process, the color of the four-color printing label is much better than the label printing machine printing similar products. But because of the sheet of paper printed self-adhesive form of a single sheet of paper, can not rewind, so such products only manual labeling, automatic labeling machine can not be automatically labeled. Sheetfed printing is suitable for large area stickers for color prints. Such as posters, posters, large areas of labels, etc., are not limited to label products. It can be said that one sheet of paper stickers printing is an important part of the sticker printing industry.
In the printing method of the web paper stickers, the current convexity accounts for 97%, the silk screen is 1%, the offset printing is 1% and the flexo printing accounts for 1%.
As a result of the use of web printing processing, all processes are completed on a machine, so the production efficiency, low consumption, low cost. At present, China's label printing press for the letterpress printing form, less function, only suitable for printing simple color, line type of label, in the printing quality as a single sheet offset printing label. However, the use of web-processed labels can be rewound into rolls, can be used in automatic labeling machine, bar code printer, electronic and other equipment, easy to automate production. Web printing stickers label is the current world of stickers printing the mainstream.
one. Film printing process of self - adhesive film
Compared with ordinary paper, film materials have many advantages, film printing is the future direction of stickers printing. We briefly introduce the structural properties of the film material, printing and postpress processing technology:
1, the structure and characteristics of thin film materials
The film material is the same as the paper material structure, and the only difference is that the material surface needs to be treated.
(2) surface characteristics and treatment methods
Ink layer in the printed material on the pattern of the principle of penetration, evaporation, conjunctiva, curing. Due to the high film density, the ink is only volatile, conjunctiva. Curing process without infiltration, for this film surface to be special treatment. The effect of surface treatment is to improve the surface tension of the film, making it greater than the surface tension of the ink, so as to achieve the correct combination of ink and film materials. Surface treatment usually has the following methods:
A Corona treatment: through the high voltage charge to the surface of the film discharge treatment, and ultimately to increase the surface energy that is the purpose of surface tension. Corona treatment is generally carried out at the film manufacturer, because the surface tension is time-limited, requiring a rigorous testing before printing. As a result, some advanced equipment has pre-printed corona treatment devices to print high-quality film products.
B printing process: chemically change the film surface properties, making it suitable for ink printing or ribbon printing.
C surface coating: the use of chemical substances in the film surface coating, increase the surface tension, change the surface properties.
2, the film material printing process
(1) film material printing process
Printing: UV offset printing ink printing; embossing: divided into ordinary resin ink printing and UV embossing ink printing; flexo: divided into water-based; ink-based printing; Ink printing, solvent ink printing and UV ink printing; silk screen: divided into UV ink printing and solvent ink printing; combination printing: divided into embossed + silk screen, embossed + flexo, flexo + silk screen, offset + Printing method. Here are some more specific use of the printing method:
A, ordinary resin ink printing. This is the most commonly used method, due to the existence of drying problems, there are two drying methods: cut leaflets, shelves drying. This method of drying a long time, covers an area of large, easy to rub dirty.
Fumo. Will be dry ink wrapped in the film, we should pay attention to avoid the release of laminating, prevention of laminating failure.
B, UV ink embossing. This method of printing quality is good, high efficiency, is one of the most developed in China, the most suitable for the national conditions of the printing process. As the domestic printing equipment generally do not carry UV devices, film printing is limited, so equipment updates, transformation is a prerequisite for printing film.
C, solvent ink flexo.
This is the traditional printing method, good quality. As the solvent ink surface tension is low, the film surface tension requirements are not as strict as other inks, so the ink layer is firm, the process is relatively simple. But the solvent impact of environmental protection and harmful to the human body, is a forthcoming out of the printing method.
D, water-based ink flexo. This is the world's most advanced printing methods, low cost, good quality, pollution-free. But the process is strict, the film surface tension must be above 40 dyne, the ink PH value, viscosity has strict requirements. The process is a great development of the domestic technology, but by the development of equipment is very slow development.
E, UV ink flexo printing. Features with UV embossing, high cost, but the film surface tension is relatively strict. General manufacturers more use of water-based ink printing, UV polishing the way to reduce costs and increase the printing effect.
F, UV ink print. This new process can be leaflets can also be reel printing, high cost, good quality. Leaflets do not have to hang up, roll can be printed at high speed.
G, solvent ink silk screen. This is the traditional process, the general single with manual printing, roll material with a linkage printing. More than 95% for single leaf printing, the effect is good, low cost But the solvent silk screen printing ink harmful to the human body, pollute the environment.
H, UV offset printing ink. As the glue used resin ink, so ordinary offset printing can not print film. Some manufacturers in the printing of PVC on the use of single overprint, shelves dry, the final way of laminating. But because the ink is not easy to dry, easy to rub dirty, so waste, productivity is very low. And the use of UV offset printing of the above problems are all avoided, and can print a high level of thin film products to the level.
I, gravure printing. Gravure is rarely printed on stickers, but print quality is the best of all printing methods and is a promising printing method. In the country as long as the postpress processing, the existing equipment can print high-quality self-adhesive labels.
J, combined printing, also known as composite printing, is the world's packaging and printing industry in the most advanced one of the printing method. According to the different design, in the same pattern using several methods of printing, to achieve the best visual effects. Foreign equipment is very common in China, there are two types of China: Japan's LINTEC SR-520B, SHIKY company's F-330, the former for the logo + silk screen, which is offset + embossed.
(2) ink drying method
The ink on the film was divided into: oxidative polymerization drying (tree finger ink), volatile conjunctival drying (solvent ink), evaporation conjunctival drying (water-based ink) and light curing drying (UV ink).
Drying method is divided into: hot air drying, electric drying (far infrared class), UV curing and drying.
Drying requirements: ink fully dry; does not affect the physical and chemical properties of the film; does not affect the characteristics of the adhesive; no effect on the end of paper.
Methods to improve the effect of ink drying:
A, the use of additives to improve the drying speed of ink. Such as resin ink drying oil; water-based ink plus special additives, solvent ink plus low boiling point solvent. However, note that the additive will change the brightness and brightness of the ink and can not affect the bond strength of the ink with the film due to the additive.
B, change the running speed of the film material.
C, change the temperature inside the oven or change the intensity of the UV light source.
D, choose the appropriate film material.
(3) Postpress process
The post-press process of the film material is substantially the same as that of the paper sheet. Such as bronzing, laminating, punching, folding, cutting, rewinding, waste discharge, die cutting, etc. are used for film-like self-adhesive label processing.