How does cross-linked shrink film maintain flexibility and toughness in low temperature environments?

Crosslinked shrink film is a type of polymer film treated with special cross-linking technology. Its basic materials are mostly thermoplastic plastics such as polyethylene (PE) and polypropylene (PP). Through physical or chemical methods, such as electron beam radiation, chemical cross-linking agents, etc., chemical bonds are formed between originally linear polymer chains to form a three-dimensional network structure. This structural change significantly improves the mechanical strength, heat resistance, chemical corrosion resistance and dimensional stability of the film.

In low-temperature environments, ordinary polymer materials tend to become hard and brittle due to the reduction in molecular chain mobility, resulting in a significant decrease in the flexibility and toughness of the material. However, cross-linked shrink film can maintain its flexibility and toughness under such low temperature conditions, mainly due to its unique cross-linked structure.

1. The “chain effect” of chemical bonds
Cross-linking technology allows the formation of more chemical bonds between the molecular chains of the film. These chemical bonds are like chains, tightly connecting the originally dispersed molecular chains. At low temperatures, although the overall mobility of the molecular chain decreases, these chemical bonds still have a certain degree of mobility and can "buffer" the impact of low temperature on material properties to a certain extent. This "chain effect" not only enhances the overall strength of the material, but also ensures that the film can still maintain good flexibility and toughness at low temperatures.

2. “Micromotion” of molecular chains
In the cross-linked structure, although most of the molecular chains are fixed by chemical bonds, there is still a small part of the molecular chains that remain relatively free. These "free chains" can still carry out small movements at low temperatures, thereby maintaining a certain degree of film stability. of flexibility. This micro-movement helps the film disperse stress more evenly when subjected to external forces and avoid rupture caused by local stress concentration.

3. Dimensional stability at low temperature
Cross-linked shrink film can also maintain good dimensional stability at low temperatures, which is also one of the important factors in maintaining its flexibility and toughness. Due to the existence of the cross-linked structure, the film is not prone to shrink or expand at low temperatures, thus ensuring tight wrapping and effective protection of packaged items.

The excellent performance of cross-linked shrink film in low temperature environments makes it widely used in many fields.

1. Food packaging
In the food industry, especially in the field of frozen food packaging, cross-linked shrink film can closely adhere to the surface of the food due to its flexibility and toughness at low temperatures, effectively preventing volume expansion and expansion caused by the freezing of water inside the food during the freezing process. Packaging cracked. At the same time, its good gas barrier properties can also extend the shelf life of food.

2. Pharmaceutical packaging
Pharmaceutical products have extremely high requirements on packaging materials, especially biological products and vaccines stored under refrigerated and frozen conditions, which require packaging materials with good low-temperature stability and sealing properties. Cross-linked shrink film can ensure the safety and effectiveness of these products during transportation and storage due to its excellent low-temperature properties.

3. Electronic product packaging
In the field of electronic products, especially for some precision components that need to be transported and stored in low temperature environments, cross-linked shrink films can provide effective shock and impact protection. Its flexibility and toughness at low temperatures enable the packaging to better absorb energy and protect internal components from damage when impacted by external forces.

4. Cold chain logistics
In cold chain logistics, cross-linked shrink film also plays an important role. Whether it is frozen food, fresh produce or other items that require cryogenic storage, cross-linked shrink film can provide a reliable packaging solution to ensure the freshness and safety of items during transportation.

With the continuous advancement of science and technology and people's increasing requirements for the performance of packaging materials, the application fields of cross-linked shrink films will continue to expand. In the future, scientific researchers will continue to explore new cross-linking technologies and material formulas to further improve the performance of cross-linked shrink films in low-temperature environments. At the same time, the rise of green packaging concepts such as environmental protection and biodegradability will also promote the development of cross-linked shrink films in a more environmentally friendly and sustainable direction.