Characteristics and production technology of heat shrinkable film

Heat shrinkable film's product features:

1. heat shrinkable film is a clean, odorless and clean packaging material.

2, heat shrinkable film, not afraid of water, dust-proof, can not only achieve the role of packaging, but also beautiful products, maintenance products.

3. heat shrinkable film has good flexibility, is not easy to be damaged, has strong explosion resistance, strong impact resistance, strong tear resistance and strong tensile force, and can replace box packaging.

4. heat shrinkable film has a large shrinkage rate, which can tightly wrap articles after thermal shrinkage. If the PE straight-through bag (with openings at both ends of the bag) is made after thermal shrinkage, the articles can be lifted at both ends of the opening, which can accept the weight of 15KG and is convenient to carry.

5. heat shrinkable film has a good transparency and a light transmittance of 80%, which can display products and publicize them invisibly, thus reducing the distribution mistakes in the logistics link.

Heat shrinkable film is easy to break when printing. It is not that the quality of PVC shrink film is not good, but that there is a solvent in the printing ink used for PVC that will dissolve the PVC film, and the volatility of this solvent is small. Therefore, if there is too much solvent in the solvent used for PVC ink, the PVC shrink film will dissolve and be broken during printing. However, if the printing ink for PVC is not used, the printing fastness is not good.

Heat shrinkable film has large elastic tensile force, which can tightly wrap products with any geometric shape, and can prevent the damage caused by bundling, and has the effects of slack prevention, rain prevention, dust prevention, theft prevention, etc. High-functional resin and auxiliary materials can be used to meet the needs of different users in a wide range; It can make single-sided sticky products, reduce the noise announced in the process of coiling and stretching, and reduce dust and sand grains in the process of transportation and storage.

Heat shrinkable film's production technology and principle Plastics include amorphous plastics and crystalline plastics. In the process of film production, when the plastic is heated and melted, the interaction between its macromolecules weakens, and the macromolecules are arranged in disorder. Even after the film is cooled, as long as its temperature is lower than the softening point, the macromolecules are still in an irregular state. If it is reheated to the high elastic temperature of polymer, and the film is stretched, the macromolecular chains will be regularly arranged in the direction of external force (stretching direction). At this time, when the film is cooled, the orientation of molecular segments is frozen. When the film is reheated, due to the activity of molecular segments, the polymer has a tendency to recover its pre-stretched size (memory function), and the oriented film is stress relaxed, and the oriented film is de-oriented, and the film shrinks back to its original size along the original stretching direction. This is the thermal shrinkage of the film. Heat-shrinkable packaging has been used more and more, and has become an important packaging form. However, at present, there are different opinions about the heat shrinkage properties of heat shrinkable films, which are general and scattered, and there is no systematic, complete and specific analysis. The thermal shrinkage properties of heat-shrinkable films are analyzed and summarized, thus providing a basis for future research on thermal shrinkage properties.

Heat shrinkable film products have the characteristics of cleanliness, environmental protection, high transparency, high shrinkage, good heat sealing performance, high surface gloss, good toughness, high tear strength, uniform heat shrinkage and suitability for automatic packaging. At present, they are widely used in the packaging of food, beverages, alcohol, electrical products, electronic products, toys and other products. It is its good shrinkage characteristics that make it a packaged product. It is used for packaging food, textile, chemical building materials and other products.

Heat shrinkable film also introduced these points:

1. The product has a smooth surface, uniform thickness, no obvious spots, no oil stains, impurities and folds;

2, the flexibility is good, and after the package is shrunk, it will fall on the cement floor from 1 meter high in different directions for three times without cracking;

3. After the package is shrunk, it will be stored at 30℃ without color change such as fading and discoloration;

4. The thermal shrinkage rate is good, the transverse shrinkage rate is 48 3%, and the longitudinal shrinkage rate is 12 3% close to the product. It can be shrunk by thermal shrinkage machine, hair dryer or boiled water.

The outstanding feature of heat shrinkable film is the phenomenon of contraction and recovery. That is, when the heat shrinkable film is created, the heating well is stretched in the corresponding direction, and then the inkstone is cooled, so that the chain molecules are arranged in the stretching direction. When the film is reheated to the quietness during stretching, the chain molecules return to the original disordered state, and the thin size also returns to the size before stretching, that is, the phenomenon of shrinking X is produced.

Gravure printing is mainly used in heat shrinkable film, and the printed graphics and texts are bright in color and good in saturation. Because it can decorate the packaging container closely, it can highlight the appearance of goods and enhance the appearance decoration of goods, which can produce a good shelf effect. In the process of labeling, the label and container can be integrated without using adhesive, which can realize the large-scale on-line operation of goods and reduce the production cost.