During long-term storage, adhesive tape's tack loss due to aging is a key issue affecting its performance. This phenomenon is primarily caused by a combination of factors, including oxidation, plasticizer volatilization, fluctuations in ambient temperature and humidity, and light exposure, and requires systematic storage management strategies.
Oxidation is the primary cause of adhesive tape aging. When the acrylate or rubber components in the adhesive are exposed to air for a long time, they react with oxygen to form free radical chain reactions, leading to molecular chain breakage or excessive crosslinking. This chemical reaction directly weakens the intermolecular forces within the adhesive, causing the previously flexible adhesive layer to gradually harden and become brittle. To slow the oxidation process, the storage environment must be strictly isolated from oxygen, such as by sealed packaging or nitrogen-filled storage. Furthermore, avoid mixing adhesive tape with metal objects to prevent metal oxides, such as rust, from catalyzing oxidation reactions and further accelerating adhesive degradation.
Plasticizer volatilization is another key factor in adhesive tape hardening. As an additive that imparts flexibility to adhesive tape, plasticizers gradually dissipate into the air over time. When its content falls below a critical value, the adhesive loses its ductility, resulting in decreased adhesion and increased brittleness. To slow this process, the storage environment must be kept cool, as the plasticizer volatilization rate increases 2-3 times for every 10°C increase in temperature. Furthermore, choosing closed packaging materials, such as aluminum foil composite bags, can effectively reduce plasticizer loss and extend the adhesive tape's effective adhesion period.
Ambient temperature and humidity fluctuations have a synergistic effect on adhesive layer performance. High temperatures accelerate the movement of adhesive molecules, weakening intermolecular forces and resulting in a temporary increase in adhesion but long-term decline. Low temperatures harden the adhesive layer, causing it to lose its elastic recovery ability. Excessively high humidity forms an isolation layer at the interface between the adhesive and the adherend, hindering a tight bond. Excessively low humidity can cause the adhesive layer to shrink and crack. Ideal storage conditions are 15-25°C and a relative humidity of 40%-60%. Avoiding a temperature difference of more than 10°C between day and night to prevent internal stress in the adhesive layer caused by thermal expansion and contraction.
Light, especially ultraviolet light, directly damages the molecular structure of adhesives. UV energy triggers photochemical reactions, causing the adhesive layer to yellow and become brittle, significantly reducing its adhesion. Experiments have shown that the peel strength of adhesive tape exposed to sunlight continuously for three months can decrease by over 50%. Therefore, it is important to store adhesive tape in a dark area, such as a light-proof cabinet or blackout curtains, to avoid direct sunlight. For adhesive tape that will be stored for a long time, it is recommended to use dark packaging materials, such as black PE film, to absorb or reflect UV rays and reduce photoaging damage.
Mechanical pressure and friction are often overlooked factors that can damage adhesive tape during storage. When stacking adhesive tape rolls, the weight of the upper layer can cause deformation of the lower layer, even leading to adhesive spillage and contamination. Frequent handling or rolling during storage can cause the adhesive layer to separate from the substrate. Proper storage is to store individual rolls flat or upright, avoiding contact and away from sources of vibration. Opened adhesive tape should be resealed in its original packaging to prevent dust accumulation and exposure to air.
Chemical contamination poses a potential risk of premature adhesive failure. Volatile substances such as acids, alkalis, and solvents can react chemically with adhesives, causing swelling, degradation, or discoloration. For example, adhesive tape exposed to oily substances can lose its adhesive properties within hours. Therefore, storage should be kept away from chemical warehouses, and different types of adhesive tape should be stored separately to prevent cross-contamination. For specialized adhesive tapes, such as those designed for high-temperature or corrosion resistance, strict adherence to packaging storage instructions is essential to prevent degradation due to environmental incompatibility.
Protecting adhesive tape's adhesion during long-term storage requires comprehensive measures, including isolation from oxidation, temperature and humidity control, protection from light and pressure, and protection against chemical contamination. By optimizing the storage environment and handling procedures, the aging process of the adhesive layer can be significantly slowed, ensuring the adhesive tape maintains stable adhesion throughout its storage period and meets subsequent usage requirements.
