Shrink sleeves work on the thermoplastic properties of heat-shrinkable materials. Sleeves are typically made of thermoplastic films such as PVC, PET, OPS, or POF, which are relaxed at room temperature. Through heat treatment, the molecular chain activity of the film increases, causing the material to shrink. The sleeve shrinks in size, thus tightly adhering to the container surface and achieving a covering effect. The shrinkage effect of shrink sleeves is closely related to the heat source and heating method. Common heating methods include hot air furnaces, steam heating, and infrared heating. During heating, heat is evenly conducted to the sleeve surface, causing the film to shrink uniformly and conform to the container's contours. The heating temperature and time must be controlled within the material's allowable range; otherwise, excessive shrinkage, deformation, or breakage may occur.
The tight fit of shrink sleeves also depends on the container shape and the initial size design of the sleeve. The label should be designed to be slightly larger than the container to ensure complete coverage of the bottle or packaging during shrinkage. After shrinkage, the sleeve is firmly fixed to the bottle surface, highlighting the printed pattern and brand information, achieving a comprehensive function of aesthetic decoration, anti-counterfeiting, and information transmission.
