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Oct 19, 2018

Development History
In  the 1930s, self-adhesive materials were first applied in the United  States. Due to the increasing demand for such special composite  materials, self-adhesive printing has gradually evolved into an  independent printing field, and self-adhesive label printing at home and  abroad. More and more companies. As  far as China is concerned, the unprecedented development of the  printing industry in terms of production scale, technology level and  market space has driven the development of self-adhesive printing and  reached an unprecedented level.
According  to statistics, in 2011 China's label market output value of 23 billion  yuan, label production of 3 billion square meters, compared with 2010,  an increase of 21.1% and 20.0% (2009 label market output value of 19  billion yuan, label production of 25 100 million square meters). In the same year, China's labels accounted for 6.4% of global label production. Therefore, China's self-adhesive label market has great potential.
The earliest self-adhesive was produced by a chemist at 3M in the United States. It  was in 1964, when he studied various adhesive formulations and  formulated a new type of adhesive that had a large viscosity but was not  easily cured. Use it to paste things, even after a long time can be easily peeled off. At the time, people thought that this glue would not have a big effect, so it didn't pay attention.
In  1973, a new tape development team from 3M Company applied the glue to  the back of the commonly used trademark, and then stuck a piece of paper  coated with a small amount of wax on the glue. In this way, the world's first trademark paper was born. As  a result, the role of self-adhesive has been discovered one after  another, and the number of people using stickers is increasing.
1. Face material: It is the carrier of the sticker content, and the back of the paper is coated with adhesive. The  surface material can be used in a wide variety of materials, generally  divided into coated paper, transparent polyvinyl chloride (PVC),  electrostatic polyvinyl chloride (PVC), polyester (PET), laser paper,  temperature resistant paper, polypropylene (PP), Polycarbonate  (PC), kraft paper, fluorescent paper, gold-plated paper, silver-plated  paper, synthetic paper, aluminum foil paper, fragile (anti-counterfeit)  paper, textured paper, cloth label (Tevek/nylon) paper, pearl paper, Sandwich coated paper, thermal paper.
2. Film  material: transparent polyester (PET), translucent polyester (PET),  transparent oriented stretched polypropylene (OPP), translucent oriented  stretched polypropylene (OPP), transparent polyvinyl chloride (PVC),  polished White  polyvinyl chloride (PVC), matt white polyvinyl chloride (PVC),  synthetic paper, polished gold (silver) polyester, matt gold (silver)  polyester.
3. Adhesive:  General-purpose super-adhesive type, general-purpose strong-adhesive  type, refrigerated food strong-adhesive type, universal re-opening type,  and fiber re-opening type. On  the one hand, it ensures the proper adhesion of the base paper and the  facial tissue, on the other hand, it ensures that the facial tissue is  peeled off and has a firm adhesiveness with the sticker.
4. Base  paper material: release paper is commonly called “bottom paper”, the  surface is low-surface energy non-sticky, and the bottom paper has a  barrier effect on the adhesive, so it is used as the attachment of the  paper to ensure that the paper can be easily removed from the paper. Peel off the bottom paper. Commonly used are white, blue, yellow glassine or onion, kraft paper, polyester (PET), coated paper, polyethylene (PE).
The  so-called self-adhesive printing is a process of transferring ink and  the like through a printing plate to a surface of a printing material  which is pre-coated with a rubber layer under a certain pressure. Compared with ordinary printing, stickers have the following characteristics:

    The investment is small and the effect is quick. Self-adhesive  prints are mostly trademarks and stickers, which have a small format,  fast printing speed and low production waste.
    Flexible printing. Stickers  are not limited by the printing method, and traditional printing houses  can be printed by offset presses or screen printers.
    It  has many functions, and its self-adhesive is widely used in food,  cosmetics, and barcodes. It can also be used as a signage in special  environments such as electronic products and mechanical products.

1:  Use of face material: molded wood free paper, coated paper art paper  (shading / mirror), transparent PVC, electrostatic PVC, polyester PET,  laser paper, temperature resistant paper, PP, PC, kraft paper,  fluorescent paper, thermal paper ,  copper wire dragon, silver silk dragon, gold-plated paper,  silver-plated paper, synthetic paper (CPC/PP/HYL/good tough paper/pearl  paper), aluminum foil paper, fragile (anti-counterfeit) paper, textured  paper, cloth label ( Tevek/nylon), pearl dragon, sandwich copper plate, thermal paper.
2:  Use film type: transparent PET Translucent PET Transparent OPP  Translucent OPP Transparent PVC Light white PVC Matte white PVC  Synthetic paper Light gold (silver) polyester Matte gold (silver)  polyester.
3:  Use type: general super-adhesive type, general-purpose strong-adhesive  type, refrigerated food strong-adhesive type, universal re-opening type,  and fiber re-opening type.
4:  Use base paper: white, blue, yellow glassine paperine (or garlic paper  onion) kraft paper polyester PET coated paper polyethylene polyethylene.
There  are two types of self-adhesive labels: one is a paper-based  self-adhesive label, and the other is a film-based self-adhesive label.
1.  Paper-based self-adhesive labels are mainly used in liquid washing  products and popular personal care products; film materials are mainly  used in medium and high-grade daily chemical products. At  present, popular personal care products and household liquid washing  products on the market account for a large proportion, so the  corresponding paper materials are used more.
2,  film-type self-adhesive labels commonly used PE, PP, PVC and other  synthetic materials, film materials are mainly white, matt, transparent  three. Since  the film material is not very suitable for printing, it is generally  corona treated or a coating is added on its surface to enhance its  printability. In  order to avoid deformation or tearing of some film materials during  printing and labeling, some materials are also subjected to directional  processing for uniaxial stretching or biaxial stretching, for example,  biaxially stretched BOPP materials are quite common.
Production process

    Cutting process
    Plate making, ink adjustment process
    Printing process
    Die making, die cutting process
    Pre-drip test
    Drop molding process
    Finishing process

Label printing

    Anti-counterfeiting  label screen printing anti-counterfeiting mainly refers to  anti-counterfeiting for the coating part and part.
    It  is recommended that the coating part should not be laminated as much as  possible, because the cost of laminating is high and it is not easy to  cut. Glazing oil is the best way.
    When making self-adhesive labels, try not to varnish as a whole, and part of it will be fine.
    The  thickness of the screen printing mesh affects the thickness of the  coating, and the degree of lightness of the diluent affects the  appearance of the coating.
    The  silk screen anti-counterfeiting technology of self-adhesive labels uses  water-based stencils for dripping anti-counterfeiting, and the others  generally use oiliness.
    The  screen printing screen used generally has a mesh size of 250-350 mesh.  Theoretically speaking, the larger the mesh number of the screen  printing mesh, the stronger the effect and the thicker the coating.
    In  actual use, it is found that the more the ink is printed, the finer the  pattern is. If the dilution is not enough, it may also be shelled.
    Silk  screen printing is related to typesetting and design. The larger the  layout space is, the better the position is adjusted when silk screen  printing. The silk screen is also related to the weather. Too moist or  too high temperature will affect the silk screen effect. Generally,  when the temperature is high, the dry water or the slow 783 should be  added. When the temperature is low, the dry water should be accelerated.
    Silk  screen should pay attention to the customer's individual label  requirements and coding have a certain relationship, if the coating on  the coating is not thin, the coating should be thicker; if the coating  is not printed, the coating should be thicker; Try to be as clear as possible and try to be as detailed as possible.
    The  silk screen is related to the order in which the labels are placed: it  is necessary to distinguish between the serial number and the serial  number.
    Screen printing should pay attention to the problem of materials, different materials have different inks and practices.
    Screen  printing should pay attention to whether the film is to be laminated  after the processing, if the part of the silk screen is easy to fall off  or wipe off, it will be laminating.
    Silk  screen should pay attention to whether it is necessary to color, the  general offset printing is better, and often the offset can not be  printed on the silk screen can be printed, so often say silk screen can  do.
    The  silkscreen technology of self-adhesive labels should understand the  performance of inks, and must understand the stencil, position,  adjustment board, repairing and washing.
    Silk screen should pay attention to the surface not to paste, do not foam;
    It  is worth reminding that it is generally recommended to do it once in  the case of dripping anti-counterfeiting, because such screens often  have a pause in the middle and may not be used.
    Screen  printing should pay attention to the production according to the  production list. If the temperature change is anti-counterfeiting, it  should be noted that the temperature change disappears or the  temperature changes color; it is necessary to pay attention to whether  the temperature change effect is reversible or irreversible.
    The  silk screen surface is measured by the performance of silver powder: it  can be scratched with nails and can not be wiped off with fingertips.

Hot stamping method
Self-adhesive  labels are a kind of material that is widely used in many aspects such  as life and work. There are also many kinds of self-adhesive bronzing  processes. This paper summarizes the self-adhesive stamping and  self-adhesive in different mechanical platforms. Hot stamping and post-hot stamping features. Among  them are a variety of hot stamping processes: cold stamping, round hot  stamping, flat stamping process characteristics and adaptation methods.
1. Hot stamping method
According  to the processing method of the self-adhesive label, the hot stamping  method is divided into a single sheet of hot stamping and a web  stamping. Sheet-fed gilding is the same as the traditional bronzing process and is processed on a dedicated bronzing machine. Web bronzing is done on the label linkage and is the most widely used processing method. At present, there are several ways to foil the roll material:
1 label machine flat pressing bronzing
For  the letterpress label printing machine, whether it is flat flat or  round flat type equipment, since the roll paper is intermittently fed,  the bronzing is all flat and flat. Under  normal circumstances, the bronzing station is an independent unit, and  some models are gilded to share one unit with die-cutting and used  separately.
2 multi-station flat pressing bronzing
Some  models have a two-station bronzing unit, such as Japan's Shiki's  SMHC-45-MWL labeling machine, one unit close to the plate, complete  horizontal bronzing, and the other unit is a separate unit, complete  vertical bronzing. This model can perform two-color bronzing at the same time.
3 processing machine flat pressing bronzing
The machine is designed for the processing of printed roll labels and labels that do not require printing. Bronzing  is a function of the processing machine. The bronzing device on the  processing machine generally adopts the flat pressing method, and its  working principle is the same as the above labeling machine.
Round press on the 4 rounds
The  bronzing plate used for round pressing and bronzing is a roller-shaped  plate. When bronzing, it is in contact with the impression cylinder to  achieve hot stamping. Round  press bronzing is suitable for use on the continuous transfer labeling  machine of continuous paper feeding, but there are certain requirements  for the feeding speed, that is to say, the printing speed is affected. However, compared with the flat pressing and ironing, the efficiency is greatly improved. The round-pressed hot stamping rolls are expensive to manufacture, so they are only suitable for long-running hot stamping.
Cold bronzing on 5 rounds
This  is a new hot stamping process. Instead of using a heated metal plate,  the printing foil is used to transfer the metal foil to achieve hot  stamping. The  process flow is: first print UV pressure sensitive adhesive at the  position where the printing needs to be bronted, dry the adhesive  through UV drying device, then use special metal foil to composite with  pressure sensitive adhesive, then peel off the metal foil, then metal The portion of the foil that needs to be transferred is transferred to the surface of the print to achieve cold stamping. The  cold stamping process has low cost, energy saving, high production  efficiency, and can utilize existing equipment components without adding  additional devices. It is a promising new process.
2. First hot stamping and post hot stamping
The  hot stamping of the self-adhesive is also divided into the first hot  stamping and the hot stamping. The first hot stamping refers to first  stamping on the labeling machine and then printing; then the hot  stamping refers to printing first, and finally bronzing. The key to hot stamping and post-hot stamping is the drying problem of the ink. There are two situations in the relationship between bronzing patterns and printed patterns: juxtaposition and overprinting. Due  to the different inks used, the label printing must be carried out by  two processes: first hot stamping and post hot stamping.
1 first hot stamping process
When  the labeling machine with the intermittent paper feeding unit is used  to print the label with ordinary ink, the first hot stamping process is  adopted. Since the ink used is an oxidative polymerization drying type,  it takes a certain time for the printed ink layer to dry completely, so  bronzing The pattern must avoid the ink. The best way to avoid ink is to pre-warm the roll material and then print it.
The  use of the first hot stamping process requires that the printed pattern  and the bronzing pattern be separated (parallel) because the surface of  the electrochemical aluminum is smooth, not inked, and cannot be  printed. The first hot stamping prevents the ink from smearing and ensures the quality of the label printing.
2 post bronzing process
The  post-hot stamping process is applied to the labeling machine where the  hot stamping parts are mounted on the back door, and UV ink is used for  printing. The  web material is first printed and the ink is dried instantaneously by a  UV drying device and then bronted on the surface of the material after  drying or on the surface of the ink. Since the ink is dry, the bronzing pattern and the printed pattern can be juxtaposed or overprinted without ink smearing.
In  the two hot stamping methods, the hot stamping is an ideal method,  which also brings convenience to the label pattern design and expands  the application range of the bronzing pattern. However, due to the limitations of the device function, the label printing cost is relatively high. The  first hot stamping process is suitable for small label processing of  simple patterns, low cost and wide application range, and is a commonly  used method for small and medium-sized printing plants.
The difference between hot stamping
As  an important metal surface finishing method, hot stamping is an  effective way to enhance the visual effects of trademarks, cartons,  labels and other products. Hot  stamping and cold stamping are the main advantages and disadvantages of  the two main hot stamping methods. In practical applications, the  appropriate hot stamping method should be selected according to the  specific conditions, mainly based on cost and quality considerations.
Advantages of hot stamping technology:

    The quality is good, the precision is high, and the edge of the hot stamping image is clear and sharp.
    The surface gloss is high and the hot stamping pattern is bright and smooth.
    Hot  stamping foils are available in a wide range of options, such as  different colors or different gloss effects, as well as hot stamping  foils for different substrates.
    Stereo hot stamping is possible.

The advantages of cold stamping technology:

    There is no need to buy more expensive special stamping equipment.
    A normal flexo plate can be used without the need to make a metal stamping plate. The plate making speed is fast, the cycle is short, and the hot stamping plate has a low production cost.
    Hot stamping speed is up to 450fpm.
    No need for heating equipment to save energy.
    In actual production, in the end, choose hot stamping technology or cold stamping technology? The answer is: it should be based on the specific circumstances. Hot stamping technology is used to achieve the best hot stamping quality and hot stamping, but at a higher cost. The quality of cold stamping is good, but it is inferior to hot stamping, but the cost is lower.

Check appearance
In  order to avoid the printing failure of the self-adhesive label caused  by the quality problem of the self-adhesive material itself, it is  necessary to carefully check the appearance quality of the self-adhesive  material before printing, so that it can be timely before printing. Find defects that may cause problems in print processing quality.
1, check the self-adhesive material has a flash
The  edge of the reel self-adhesive material is smooth and non-destructive,  which is the basis for ensuring the printing quality of the  self-adhesive label. Therefore, before printing, it is necessary to  carefully check whether the slit edge of the reel material has burrs,  whether it is stored or not. Damage  occurred due to improperness, and the roll of self-adhesive material  should be rolled down 4-5 times, and the slitting edge should be  carefully inspected.

2. Check for cracks on the self-adhesive material.
When  the self-adhesive material is cut, if the cutting tool is not properly  adjusted or the blade is not sharp enough, cracks will appear on the  face paper or the bottom paper of the self-adhesive material, and the  fiber pulled out at the crack will be adhered by the adhesive. live. The  occurrence of cracks may be continuous or random. There may be one side  of the self-adhesive material of the reel or both sides. Therefore,  before the self-adhesive material is printed on the machine, it may be  necessary to carefully check the bottom paper and Is there a small crack on the face paper?
Then,  take a sample of the paper that has been inspected above, and peel off  the backing paper to check again for cracks on the underlying paper and  the backing paper, because the cracks are sometimes very small, and can  only be found after separating the backing paper and the paper. It  is worth noting that as the ink and adhesive gradually accumulate on  the paper guide roller of the printing press during the printing  process, cracks may also occur at the edges of the self-adhesive  material. Therefore, even if printing has begun, the above problems cannot be ignored.
3, check whether the edge of the self-adhesive material is stuck, whether the bottom paper is missing silicon
The  edge of the self-adhesive material is adhered or a part of the bottom  paper is leak-coated with silicone oil. During the printing process, the  facial paper breaks during the waste process and cannot be produced  normally. Therefore,  before printing, you should take a piece of self-adhesive material that  is about 1 meter long and peel it off by hand to see if there are any  parts on the edge or other parts that cannot be smoothly and  consistently peeled off. Usually,  the edge paper and the bottom paper edge adhesion occur on a slit roll  of the entire roll of the coated self-adhesive material, and generally  only occurs at the outer layer of 7 meters to 10 meters, so that the cut  roll is encountered. There  is adhesion on the edge of the self-adhesive material. Do not  immediately assert that the whole roll of paper has this problem.
In  addition, it should be noted that peeling off light-weight facial  tissues (such as 60g/m2 and 80g/m2 facial tissue) is greater than the  force used to peel off heavy-weight facial tissue, and the lighter the  facial tissue, the tighter the hand feel when peeling off. Because  of this, sometimes the customer chooses the self-adhesive material  according to the shape required by the customer, and cannot be completed  at the normal printing speed.
4. Check whether the end face of the reel self-adhesive material is straight and the rewinding is consistent.
If  the slit end faces of the reel self-adhesive material are not uniform,  it will not only affect the registration during printing, but also cause  difficulty in discharging due to the change of the die-cut position;  when the rewinding is inconsistent, the paper force will be caused  during printing. Changes and uneven tension can also cause print quality problems.

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