Wuhan Handern Polyethylene Heat Shrinkable Film
DATE：2020/5/19 8:29:39 / READ： / SOURCE：This station
Wuhan Handern Polyethylene Heat Shrinkable Film
1 OverviewWhen the film is processed, it is stretched at a high elastic temperature above the softening temperature and below the melting temperature to make it have "memory" ability. When used, the film is wrapped in advance, and then the film is heated by external heating Shrink, so wrap the package tightly. Depending on the stretching method, it can be stretched in one direction or stretched in two directions. The film stretched in one direction is a unidirectional shrink film. The unidirectional shrink film has a lateral shrinkage rate of about 10%, and a longitudinal shrinkage rate of 60% to 70%. The film obtained by biaxial stretching is a bidirectional shrinkable film, and the shrinkage rate in the longitudinal and transverse directions is generally substantially the same, the shrinkage rate in the lateral direction is about 35% to 40%, and the longitudinal direction is about 40% to 50%. www.handern.com Hollow board equipment
Taking advantage of the shrinkage and transparency of shrink film, it is widely used in various products such as food packaging and non-food packaging. Food packaging such as fast food, lactic acid foods, beverages, snacks, beer cans, various alcohols, agricultural and sideline products, dry foods, souvenirs, packaging, labels, caps and seals. Non-food packaging such as: fiber and clothing, aerosol products, sports goods, electrical products, chemical products, pharmaceutical products, grease, detergents, stationery, office supplies, kitchen supplies, daily necessities, sundry goods, building materials, etc. www.handern.com Hollow board equipment
There are many types of shrink film, which will be introduced in detail in the section of shrink film. The polyethylene shrink film is the most extensive and the largest amount of shrink film. Compared with general polyvinyl chloride film and polypropylene film, polyethylene shrink film has the following characteristics:
1) Non-toxic, can be used for packaging food, and does not produce corrosive gas when sealed, and can be adapted to the packaging of metal hangers and other commodities. www.handern.com Hollow board equipment
2) The cutability and low temperature brittleness of the film are better than PVC and PP.
3) High thermal shrinkage.
4) Good storage stability.
5) The production process is simple. www.handern.com Hollow board equipment
6) The corresponding cost is relatively low. Taking Japan as an example, if the price index of PP is 100, PE is 60, and PVC is 150. The disadvantages of polyethylene shrink film are mainly poor transparency and higher shrinkage temperature than PVC. There are two types of polyethylene shrink film: non-cross-linked type and cross-linked type. The common type is non-cross-linked type. Generally, it is not indicated that the cross-linked type is non-cross-linked type. Polyethylene shrink film is divided into heavy packaging shrink film and light packaging shrink film according to the weight of the package. www.handern.com Hollow board equipment
2. Raw materials and formula
The shrinkage rate of polyethylene shrink film decreases with the increase of raw material density and melt flow rate. Generally MFR is below lg / omin. The recommended MFR is 0.3 ～ -0.5g / 0min. Depending on the purpose. The MFR of the resin for light packaging film can also be greater than 1g / 10min. The film thickness is generally 0.04-0.20mm, the thin type is 0.02-0.05mm, the medium type is 0.05-0.10m, and the thick type is 0.10-0.15mm. When packaging items below 400kg, the minimum thickness of the film is 0.12m, 600kg requires 0.15m, and 1200kg requires a 0.20m thick shrink film. There are special resins for shrink film abroad. In the absence of special resins, resins with similar melt flow rates are often used. Depending on the situation, lubricants or other modifiers are also added. www.handern.com Hollow board equipment
3. Manufacturing process and equipment of polyethylene shrink film
Almost all the manufacturing process of polyethylene shrink film adopts blow molding process. In order to impart stretchability, the inflation ratio is designed to be 3 or more. In order to impart low-temperature shrinkage, high shrinkage, and transparency, some also use unidirectional cold-stretched shrink film. The process of blown shrink film is: resin or resin mixture, extruded and plasticized into a simple film blank, then biaxially stretched, then cooled and shaped, trimmed and rolled to form a finished product. www.handern.com Hollow board equipment
Author：admin