(1) Principle The printed plastic film that has been developed in large quantities is ink, which is difficult to adhere to smooth, non-polar polyolefin, but people can still achieve a fairly good level by properly treating the plastic surface. Relying on the ink's super polar adhesion force, it makes the viscosity on the surface of polyolefin with little free energy. The comparison test is to assess the degree of affinity between the ink film and the polyolefin surface, or to measure the degree to which the ink wets the plastic surface, and whether it can withstand the test under changed conditions.
(2) Tools and materials, tools, spatulas, weights, refrigerators, tribometers; materials; polyolefin films processed to 38 dyne/cm², scotch tape.
(3) Method, use a scraper to make a printed sample on the polyolefin film, after drying for 24 hours, test the adhesion according to the following items.
a. Adhesive fastness, take 2 cm wide and 8 cm long glass strength 90 or 110 scotch tape, gently place it on the surface of the printed matter, put a rubber plate under the printed matter and put a piece of thin glass of 4 square centimeters on the tape Press a 200-gram weight (at this time, the pressure is 500 g/cm²), take off the weight after 30 seconds, pull one end of the tape with one hand and quickly remove it, and repeat twice depending on how the imprint falls off. The stripping is excellent, the incomplete is good, and the complete stripping is poor.
b. Kneading fastness, hold the printed sample with both hands, with the two thumbs 2 cm apart, and rub it up and down 20 times with appropriate force.
c. Scratch fastness, spread the printed matter on the platform, scratch the printed matter with a middle finger without edges and corners, and hold it up to the light to see if it falls off.
b. Fastness to rubbing, press the plate with fixed weight and fixed surface on the surface of the above-mentioned printing sample or scraping sample (sometimes the plate is glued with a blanket), the plate is mechanically connected with the motor, and the printing sample is printed at a speed of 37 revolutions per minute The surface makes reciprocating frictional movement, and after the specified number of frictions, observe the wear condition during the period.
e. Freezing fastness of printed products, freeze the printed samples made above at -30°C for 2 hours, and test the fastness according to the method of fastness to rubbing.