Definition
Ink decolorization wear resistance tester is a special testing equipment used to evaluate the friction resistance of ink layers on the surface of printed products. It quantitatively measures the wear fastness and peeling resistance of the ink layer by simulating the friction that printed matter may experience in transportation, handling and daily use. This equipment plays an important role in packaging printing, label manufacturing, publishing printing and quality control of various commercial printed materials.
Principle
The core working principle of the equipment is to simulate and quantify the effect of friction on the ink layer. The basic working mode is that the specimen is fixed on a horizontal platform and a friction head with defined surface characteristics and pressures (usually wrapped in standard friction media such as white test paper or a specific fabric) is frictioned in a reciprocating or rotating straight line on the surface of the specimen. Parameters such as friction frequency, pressure, speed and stroke are set and controlled in strict accordance with relevant standards. After a predetermined number of frictions, the abrasion resistance of the specimen is evaluated by comparing and observing the degree of ink peeling, transfer, or color change in the friction area of the specimen, or quantitatively measuring it using instruments such as colorimeters. The relationship between the applied force and the friction effect can be expressed as follows: the product of the friction effect and the positive pressure and friction distance shows a positive correlation trend under certain conditions.
Measurement methods and standards
The measurement process usually follows a standardized operating procedure. First, the specimen and friction medium that meet the dimensional requirements are prepared according to the purpose of the test (such as dry friction and wet friction). The specimen is fixed flat on the base of the testing machine, the friction head wrapped in the friction medium is installed and fixed, and the test parameters are set according to the standards (such as ASTM D5264, TAPPI T830, GB/T 7706, etc.), including the load weight (such as 2.2 N), the friction speed (such as 21 times/min) and the number of frictions (such as 50 times, 100 times, etc.). After starting the equipment to complete the friction test, take out the specimen and friction medium. The evaluation methods mainly include visual grading and instrumental measurement. Visual grading is a comparison of the rubbed specimen to an unfrictioned part or a standard grayscale sample card to assess the ink shedding or media staining grade. Instrumental measurement uses a colorimeter to measure the color difference value ΔE between the friction area and the non-friction area for quantitative analysis.
Influencing factors
The results of ink decolorization and wear resistance test are affected by multiple factors. The properties of the printing substrate, such as the smoothness of the paper, the strength of the coating layer, or the surface tension of the plastic film, directly affect the adhesion fastness of the ink. The ink system itself is key, including the type of binder, pigment dispersion, drying and curing mechanism, and the hardness and toughness of the final ink layer. Printing process parameters such as printing pressure, drying conditions, and whether to apply post-press processing such as varnishing and lamination can also significantly change the surface properties of the ink layer. From the perspective of test conditions, the type of friction medium (such as the quantitation of the test paper, surface roughness), the applied pressure, the movement mode and speed of the friction head, and the ambient temperature and humidity will affect the repeatability and comparability of the test results.
Applications
The application of this testing machine runs through multiple aspects of printed quality control. In the packaging industry, it is used to test the wear resistance of the surface graphics and texts of food, medicine, cosmetics and other commodity packaging boxes during stacking and transportation, and ensure the appearance integrity during the shelf life. In the field of label and bill printing, verify the wear fastness of barcodes, QR codes and important information to ensure their readability and service life. In publishing and commercial printing, the durability performance of products such as book covers, albums, and advertising pages is evaluated. In addition, it is also commonly used for raw material warehousing inspection, printing process research and development and optimization, and comparative testing of different ink or substrate formulations to provide data support for production decisions.
Equipment selection considerations
When choosing the right ink decolorization wear resistance tester, it is necessary to comprehensively consider the technical parameters and functional requirements. First of all, the main test standards to be followed should be clarified to ensure that the core parameters such as stroke, pressure range, counting capacity, and friction head size of the equipment comply with the standard regulations. Secondly, according to the common test types, consider whether the equipment is compatible with multiple test modes such as dry friction and wet friction, and whether it is easy to replace different friction heads and fixtures. The convenience and safety of the equipment, such as whether the human-machine interface is clear, whether the fixture is easy to install, and whether there are safety protection devices, also affect the daily use experience. The integrity of data logging is a concern, with some models equipped with printers or data interfaces for easy traceability and analysis of results. Finally, the manufacturing process, material durability of the equipment, and the technical support and service capabilities of the supplier are the basis for ensuring the long-term stable operation of the equipment.