Optimizing the unwinding performance of low-temperature packing tape in low-temperature environments requires comprehensive adjustments across multiple dimensions, including material formulation, substrate selection, process design, and installation. This is to avoid breakage caused by low-temperature embrittlement, reduced tack, or stress concentration. Low temperatures decrease the mobility of adhesive molecular chains in low-temperature packing tape, reducing elasticity and flexibility, making it difficult to disperse stress through deformation. When unwinding the tape from the core, insufficient tack or a brittle substrate can lead to stress concentration at bending points, causing crack propagation. Especially at extreme low temperatures, the adhesive layer may even peel off from the substrate due to shrinkage differences, resulting in adhesive layer breakage or residue during unwinding. Therefore, optimization should focus on improving the low-temperature flexibility of the adhesive layer, enhancing the cold resistance of the substrate, and reducing unwinding stress.
Adhesive formulation is a core factor affecting unwinding performance. Traditional rubber-based or acrylic adhesives tend to harden at low temperatures and require modification to improve their low-temperature adaptability. For example, introducing long-chain alkyl or siloxane segments can lower the glass transition temperature of the adhesive, allowing it to remain flexible at low temperatures. Using copolymerization technology to combine elastomers (such as polyurethane) with acrylic monomers can enhance the toughness and tear resistance of the adhesive layer. Furthermore, adjusting the curing agent ratio or using a latent curing agent can slow down the curing speed of the adhesive at low temperatures, preventing tearing during unwinding due to incomplete curing.
The cold resistance of the substrate directly affects the low-temperature packing tape's resistance to breakage at low temperatures. Ordinary BOPP or PE films are prone to embrittlement at low temperatures, requiring the selection of low-temperature resistant substrates, such as PET film or co-extruded composite film. PET film has a higher glass transition temperature, maintaining good flexibility at low temperatures; while co-extruded composite film, through a multi-layer structure (such as PE/EVA co-extrusion), can combine the advantages of each layer, improving overall cold resistance. For special applications, fabric-reinforced substrates (such as fiberglass cloth) can be used, using the fiber's toughness to distribute stress during unwinding and prevent the low-temperature packing tape from breaking.
The structural design of low-temperature packing tape also has a crucial impact on its unwinding performance. Optimizing the thickness and distribution of the adhesive layer can reduce stress concentration during unwinding. For example, using a gradient coating process, with a thicker adhesive layer at the core and gradually thinning towards the outer layer, can balance the tension distribution during unwinding. Adding microspherical elastomer particles to the adhesive layer can form a stress buffer layer, absorbing the impact energy during unwinding. Furthermore, adjusting the width and core diameter of the low-temperature packing tape, avoiding excessively narrow or small cores that result in an excessively small bending radius during unwinding, is also an effective way to reduce breakage.
Controlling the construction environment is an external guarantee for optimizing unwinding performance. In low-temperature environments, low-temperature packing tape needs to be stored and applied at suitable temperatures to avoid adhesive layer shrinkage or substrate embrittlement due to temperature differences. Before application, the low-temperature packing tape can be pre-placed in a warm environment for a period of time to bring its temperature close to room temperature. During unwinding, a segmented application method can be used, unfolding only an appropriate length of low-temperature packing tape at a time and fixing it immediately to avoid large areas being exposed to low temperatures. For extreme low-temperature environments, heating equipment (such as a heat gun) can be used for localized preheating of the low-temperature packing tape. However, temperature control is crucial to avoid overheating, which could soften the adhesive layer or deform the substrate.
Strict management of storage conditions is also essential for low-temperature packing tape. Low temperatures, humidity, or direct sunlight accelerate performance degradation. It must be stored in a dry, cool, and well-ventilated environment, avoiding contact with acids, alkalis, and organic solvents. Storage temperature should be maintained within a suitable range to prevent excessive temperature fluctuations that could reduce the interfacial adhesion between the adhesive layer and the substrate. Furthermore, low-temperature packing tape should be stacked horizontally to avoid vertical stacking, which could deform the core and affect the uniformity of tension during unwinding.
Through comprehensive adjustments in material modification, structural optimization, construction control, and storage management, the unwinding performance of low-temperature packing tape can be significantly improved, preventing breakage. These optimization measures are not only applicable to general packaging scenarios but also provide a reference for the application of low-temperature packing tape in extreme low-temperature environments such as cold chain logistics and polar scientific expeditions.
