Manufacturing technology and characteristic analys

Analysis on the manufacturing process and characteristics of food container packaging and in mold labels

in mold labels are mostly used for trademarks and label descriptions of food packaging, and play an important role in food logistics, anti-counterfeiting, identification and so on. In mold labeling is a new technology with great potential in China. Its promotion replaces the labeling machine, reduces the production cost of manufacturers, improves the recycling rate of food packaging (containers), reduces food inventory, shortens the production cycle, and improves production efficiency. It is deeply welcomed by people in the food and packaging industry

in mold label manufacturing process

the manufacturing principle of in mold label is to apply a printed paper, composite or thin label with a special hot-melt adhesive on the back, and put it in the model before plastic blowing, injection molding or hot forming to generate a plastic bottle or basin

manufacturing essentials of in mold label: first, put the label on the inner wall of the mold; Then, insert the suction plastic pipe into the inner wall of the mold wrapping the label until the mold is completely closed, so that the air fills the entire space in the closed mold; Finally, the heated plastic expands rapidly and presses against the inner wall of the mold, fixing the label on the bottle, and the finished bottle comes out of the mold

pay attention to large label materials in the mold.

ordinary label synthetic paper has poor surface smoothness, low strength, small elastic deformation, and high-grade color printing is difficult. It is suitable for large-area application of barrels. The paper label is easy to deform when encountering water or moisture, which reduces its use value. However, it is less affected by static electricity when used, and the loss when blowing the bottle to absorb the label is relatively small. Paper labels and plastic bottles are not homogeneous materials, which is not conducive to the recycling of bottle bodies. The film material is a special multi-layer coextrusion surface material with smooth surface, which can be printed in a variety of printing methods. In the process of label processing, deformation f will not cause overprint and inaccurate die cutting. Some film materials can stretch, shrink and deform. When applied to the bottle body, they can deform with the shape of the powder bottle body. After compounding to the surface of the bottle body, there will be no wrinkle of the label. Because the oil will not penetrate into the surface of the film material, the label printed by the film material has bright color, and the color effect is much better than that of paper materials. Now, plastic film in mold labels are generally used at home and abroad to effectively block all kinds of vibrating materials

in mold labels are required to have good printability, so that the powder is firmly attached to the surface of the material in the oil, and have good processability in the post-processing process, which is suitable for die cutting and cold stamping. The label material in the mold should also have good use characteristics, and can be integrated with the plastic bottle during blow molding. In mold label material structure is composed of printing surface, intermediate layer and adhesive layer. The function of the printing surface is to accept the oil and form color graphics and texts: the middle layer supports the printing surface, gives sufficient stiffness and transparency to the material, does not deform on the printing machine and under the action of high temperature, and ensures the accuracy of overprint. The adhesive layer melts under the action of temperature separation, so that the label material and the plastic container are integrated to ensure that the label and the plastic bottle are firmly stuck together. There are two kinds of structures on the surface of the adhesive layer: flat non striated structure and striated structure. The wrinkle free structure is suitable for small area labels when in direct contact with the blank and natural exhaust. Grain structure refers to the adhesive layer with grain structure stamped on the surface of the adhesive layer, and the gas between the label and the bottle body is vented through the exhaust channel of the grain during labeling. The generation of bubbles is reduced, and the glue dry layer also has antistatic property. Prevent double sheets during printing; The adhesive layer should also have a certain sliding property to ensure the smooth separation of labels and the smooth progress of printing

specific method of making in mold label

take PP bottle as an example. The label is also made of PP synthetic paper. After surface treatment and trademark printing, it is coated with special hot-melt adhesive on the back and die-cut. The in mold label is divided into front label and back label according to the different position dishes, that is, the trademark pasted on the front or back of the package. The printed labels are stacked in single sheet form, and the front label and back label are placed in two boxes of the in mold labeling machine respectively. At the beginning of a cycle of the mold, the mold of the bottle body is opened, and the printed front label and back label are sucked up by the manipulator and placed in the corresponding positions in the mold. The label printing faces the inner wall of the mold, and the small hole on the mold absorbs air to firmly absorb the label in the mold with vacuum. At the same time, the plastic bottle raw materials are heated and droop in a soft tube, and the molds with labels adsorbed on the inner wall are quickly closed. Air is blown into the hose to make the plastic bottle close to the inner wall of the mold. At this time, the temperature in the whole mold is quite high. When the back of the label is close to the bottle body, the solid adhesive coated on the back of the label begins to melt, and the label and the plastic bottle body are combined in the mold. When the mold is opened, the plastic bottle body is formed, the label and the bottle body are integrated, and the printed trademark is embedded on the surface of the plastic products. In this example, the label and the bottle are on the same surface, as if there is no label, and the color graphics and text are directly printed on the surface of the bottle

in mold labeling extraction method can not be ignored

after cutting into labels, use the manipulator to suck them into the mold cavity one by one, and use the extruded plastic temperature and inhaled air pressure to melt the labels and plastic bottles into one. Now, there are two ways to label inside chess: vacuum negative pressure mode suction and electrostatic mode suction. Vacuum mode suction is a common method. Add several vacuum suction holes on the original mold. No casting special equipment, low cost, good use effect, and it is not easy to detect the vacuum imprint. This technology is now very mature; The electrostatic molding method can also realize the adsorption of labels in the mold. The advantage is that there is no need to transform the original blow molding equipment. however. At present, such equipment has not been seen in China

advantages of in mold label

the appearance is novel and beautiful. The in mold label is formed together with the plastic container. The in mold label and the bottle body naturally touch together, and the inlay is firm. The label changes with the shape of the powder bottle body. You can't see the edges and corners of the label on the plastic bottle body, and the appearance looks very beautiful. The label deforms with the deformation of the powder bottle, so there will be no blistering, wrinkling and other phenomena. It feels smooth, especially for daily chemical products with labels as the main outer packaging. The advantages are self-evident. The printing effect of chess labels is good. It can print detailed fenggong and delicate design patterns, and has strong visual expression. The in mold labels are closely combined with the bottle body, and the labels and containers have good drillability. The in mold labels have no edges and corners, and the labels will not be separated from the containers when they are warped and extruded, There will be no signs of warping and falling like self-adhesive. It can resist twist, scratch and pollution in the process of production and transportation, so that the label can remain complete and beautiful for a long time. In mold labels will not bulge or mildew in wet environment

strong anti-counterfeiting function, in mold labeling. On the other hand, it completely solves the relatively complex system of pollutants, requiring special processing molds (in mold labeling manipulator) or modifying the original molds. A set of molds costs hundreds of thousands of yuan, which greatly reduces the possibility of counterfeiting, thus providing a relatively reliable means of brand protection for users and manufacturers. The investment of disposable equipment is large. At present, only a few domestic companies can provide in mold label labeling services. There are many changes in mold design, label printing and processing, and labeling forming process. Therefore, there are technical barriers to labels in the mold, and it is difficult to forge and imitate them. In contrast, Buqian glue labels are now very popular, and the technology is mature. Counterfeiting is not only easy, but also the cost is very low. Therefore, the fake and inferior products of self-adhesive labels are rampant, damaging the interests of manufacturers

it is safe and environmentally friendly. Traditional labels should be labeled after the container is formed. The in mold label and container molding are completed at one time to avoid the possible pollution to the bottle body caused by the labeling process. The in mold label is completely integrated with the bottle body. The in mold label material usually uses the same material as the plastic bottle body. After the product is used, the plastic bottle can be crushed and recycled together, and the recycling and reuse rate is higher and the cost is low. Therefore, some people classify the in mold label as a green and environmentally friendly packaging material, while the plastic bottle with adhesive label is more troublesome to recycle. It is necessary to tear off the adhesive label first, remove the adhesive on the bottle, and then recycle, In contrast, the efficiency of recycling is low, and the cost of recycling is relatively high. Therefore, it can be said that the label in chess is in line with the development trend of green packaging

high efficiency, high benefit, in mold label and container molding are completed at one time, which reduces labor costs, no post-processing, immediate delivery, reduces inventory, shortens production cycle, and improves production efficiency. In addition, it has good printing performance and can print exquisite patterns in the same way as the label with thousands of glue

defects of in mold labels

in mold labels, if self-adhesive labels are used in practical applications. There is a problem in the printing process. Even if reprinted, it will only waste some labels; Even if it has been pasted on the plastic bottle, if you are not satisfied with the labeling style, you can continue to use it by changing the bottle label. However, if the in mold label is not satisfied with the printing or labeling process, it will cause double waste of bottle body and label

the use of in mold labels requires expensive molds, special container blow molding or injection molding equipment, which makes in mold labels not easily acceptable in the market. Now it only accounts for 2% to 3% of the market share. However, the high cost of in mold labels plays a role in cost anti-counterfeiting. At the same time, the process of in mold label is also more complex than ordinary process. It also plays the purpose of craft anti-counterfeiting. The in mold label needs a relatively large number of prints to reduce the process cost. It is not suitable for applications such as short version and time-consuming label manufacturing

if the container made by blow molding process adopts in mold label. The shape of the container (1) must be considered according to the technical requirements of the spring. If the curvature of the container is too large, such as a round bottle, it will cause difficulty in venting in the labeling in the mold; in addition, if the volume of the blow molded container is too large, it is not suitable to use the label in the mold. When there is a problem in design or sales, the bottle body and label will be invalidated. If the old process is adopted, only the bottle body or label will be lost

if the container made of blow molding process needs to use in mold label, the curvature of the container should be considered. If the curvature of the container is too large and the round bottle is added, it is difficult to exhaust in the process of in mold label labeling, and the in mold label is not applicable. In addition, blow molded containers are too large, and it is not suitable to use in mold labels

however, the use of in mold labels requires special die-cutting equipment and labeling equipment in the printing process, and the printing process requires attention to electrostatic treatment. Therefore, the printing and processing cost of in mold labels may be higher than that of traditional labels

at present, in mold labeling is the transformation of skills, except for the labels and instructions of plastic barrels, bottles and boxes used for long-term freezing or contact with water, such as dairy products, ice cream, condiments, salad oil, soy sauce, vinegar, coffee, fruit juice, tea drinks, yogurt and so on. In addition, it is also used in HDPE, PP, pet, PS and other plastic packaging, involving medical, mechanical, agricultural and other related industries. Now the in mold labels are moving towards recyclable pre labeled containers, which not only improves the speed of assembly, reduces the cost of products, but also meets the needs of environmental protection, experts predict,