Printed adhesive tape is mainly used for product packaging, such as sealing boxes, bundling, and labeling. Printed packaging tape requires good adhesion, certain strength, and toughness to ensure the packaging's firmness and airtightness. So, what are the test methods for printed adhesive tape?
① Printing Quality Inspection: Visual inspection combined with standard color cards, magnifying glasses, and other tools is used to evaluate the clarity, color, and registration accuracy of printed patterns and text. For color deviation detection, a colorimeter can be used for precise measurement; the color difference from the standard color sample should meet the specified range.
② Tape Surface and Edge Quality Inspection: Under natural light or standard lighting conditions, visually observe the tape surface for defects such as bubbles, particles, wrinkles, scratches, and delamination, as well as whether the edges are neat, curled, or uneven in width. For minor defects, magnifying equipment such as microscopes can be used for observation.
① Width Measurement: Using measuring tools of the required accuracy (such as calipers, micrometers, etc.), measure the width at different locations on the tape. Take the average value as the tape width. The measurement result should meet the nominal value and tolerance requirements.
② Length Measurement: Unroll the tape from the core at a uniform speed. Use a meter counter or other length measuring device to measure the actual length of the tape. The measured value should not be less than the nominal length.
③ Thickness Measurement: Use a thickness gauge to measure the thickness at different locations on the tape, including the substrate thickness and the total thickness (substrate + adhesive thickness). The measurement accuracy of the thickness gauge should meet the testing requirements, and the measurement results must meet the thickness range and uniformity requirements specified in the product standard.
① Tensile Strength and Elongation at Break Test: According to relevant standards, cut a sample of a certain size from the tape and conduct a tensile test on a universal testing machine at the specified tensile speed. Record the maximum force value at break (i.e., tensile strength) and the elongation at break (calculate the elongation at break). The testing process should strictly control environmental conditions such as temperature and humidity to ensure the accuracy of test results.
② Initial Tack Test: The commonly used rolling ball method for initial tack testing involves placing a steel ball of a specified size on an inclined adhesive tape and observing the rolling distance or stopping position of the ball to assess the tape's initial tack. The testing equipment should meet standard requirements and must be calibrated before each test.
③ Holding Tack Test: Using a holding tack tester, the adhesive tape sample is adhered to a specified test plate, and a certain pressure is applied. The test plate is then suspended vertically, and under specified temperature and time conditions, the tape is observed for phenomena such as detachment or displacement to determine whether the tape's holding tack meets the requirements. The accuracy and stability of the holding tack tester have a significant impact on the test results and require regular maintenance and calibration.
④ Peel Strength Test: The adhesive tape sample is adhered to the surface of the object to be bonded. At the specified peel speed and angle, a tensile testing machine is used to peel the tape from the surface. The force change during peeling is recorded, and the average peel strength is calculated. The key to peel strength testing is ensuring the quality of the sample adhesion, the accuracy of the peel speed and angle, and the precision of the testing equipment.
① Hazardous Substance Limit Detection in Adhesives: Chemical analysis methods, such as gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), are used to qualitatively and quantitatively analyze harmful substances such as formaldehyde, benzene, toluene, and xylene in adhesives. The test results should meet the limits specified in national standards. The testing process must be strictly carried out according to the relevant standard operating procedures to ensure the accuracy and reliability of the test data.
② Chemical Corrosion Resistance Test: The tape sample is immersed in a chemical reagent of specified concentration and temperature. The appearance changes of the tape are observed periodically over a certain period (e.g., swelling, discoloration, delamination, etc.), and the changes in the physical properties of the tape (e.g., tensile strength, peel strength, etc.) are tested to assess the tape's chemical corrosion resistance. The type, concentration, immersion time, and temperature of the chemical reagents used in the test should be determined according to the tape's intended use environment and relevant standards.
① Degradability Test: For biodegradable printed tapes, appropriate testing methods are used based on their degradation methods (e.g., biodegradation, photodegradation, hydrolysis, etc.). For example, the biodegradability test can bury the tape sample in a specific soil or composting environment, and monitor the mass loss, changes in mechanical properties, and degradation products of the tape over a certain period to assess whether its biodegradability meets the standard requirements. The testing process must simulate actual environmental conditions and strictly control the test parameters.
② Recyclability Assessment: By analyzing the material composition of the printed tape and combining it with existing recycling technologies, the feasibility and methods of recycling are assessed. For example, for printed tapes with plastic film substrates, their compatibility and processability in plastic recycling systems can be analyzed based on their material type (e.g., BOPP, PET, etc.).
③ Heavy Metal Content Detection: The content of heavy metals (lead, mercury, cadmium, chromium, etc.) in the printed tape is detected using instruments such as atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). The test results should be lower than the limits specified in national standards. The testing process must follow the sample preparation and analysis methods of relevant standards to ensure the accuracy and reliability of the test results.
