Source: Link Testing Instruments co.,ltd
Abrasion resistance is an important or even key indicator to characterize the quality of printed materials. For example, plastic label films and plastic packaging bags in the surface printing process will produce ink layers on the surface during product transportation, storage and transportation, sales and use. The rub effect. If the ink layer has poor bonding fastness (that is, poor wear resistance), the ink layer is susceptible to wear, which seriously affects the appearance of the product and leads to the lack of important product information. The degree of abrasion of the printing ink layer depends on the transportation conditions, such as temperature, humidity, time, frictional contact, etc., and the degree of the ink layer bonding fastness of the finished product after printing is acceptable to the producer and user. Reflected by reasonable performance indicators, this article uses the MCJ-05 Rub tester independently developed by Link Testing to introduce an effective method for testing the wear resistance of printed materials under laboratory environmental conditions and effective characterization of the wear resistance. , Provide powerful technical and data references for related industries.
Test method and instrument
This article refers to the American standard ASTM D 5264-98 (2011) "Standard Test Method for Abrasion Resistance of Printed Materials Using Sutherland Rub Tester", which is used for reference domestic and abroad. This standard can be used to evaluate the relative abrasion resistance of printing inks, coatings, composite films and sheets. Buyers and sellers of printed materials need to verify whether the wear resistance of the materials meets the agreed standard requirements. This standard can provide a reasonable and simple verification method for this purpose.
The MCJ-05 Rub tester independently developed by Link Testing is a professional test for the abrasion resistance of the printed ink layer, the abrasion resistance of the photosensitive layer of the PS plate and the abrasion resistance of the surface coating of related products. It can effectively analyze the abrasion resistance of the printed matter. Problems such as durability, ink layer fastness and coating hardness of other products.
Test principle: Install the sample on the rubber pad of the base platform of the rub tester, and cut and rub according to the 0.91Kg (2-lb) or 1.81Kg (4-lb) load block (the load block is determined according to the actual needs of the test) Paper, friction paper is installed on the load block. The duration of sample friction is determined by the number and speed of friction (a friction refers to a reciprocating cycle). The friction frequency and speed need to be preset in the friction tester. After the test, check the damage degree of the printed layer of the sample. Analyze the amount of ink falling off the friction paper from the sample, and compare this result with a standard sample tested by the same method.
Test sample and test process
Test sample: Plastic label film on the surface of a certain brand of 4 liter lubricating oil drum (surface printing process).
1. Sample preparation:
(1) According to the size of the load block, cut the friction paper into a suitable size, 230 mm × 51 mm (2lb) or 270mm × 51 mm (4lb); the size of the load friction pad is 102 mm × 51 mm.
(2) The sample should be flat and free of holes, scratches, wrinkles or other surface defects. In addition, when testing multiple samples, the ink coverage and ink density of each sample should be the same or similar.
(3) For the test single sample, the size of the platform friction pad is 390 mm × 76 mm, and the sample is also cut into 390 mm × 76 mm.
Unless otherwise specified, place the sample in an environment of 23±1℃ and 50±2%RH for a period of time.
2. Test process:
(1) Use a reflective color densitometer to measure the color density of the ink layer to be ground on the sample, and take the average of 3 points;
(2) Install the platform friction pad on the top of the base platform of the friction tester and the bottom surface of the load block;
(3) Select the load block according to the type of test printing substrate. This test selects the heavier load block of 17.8N (4lb), which is suitable for samples in a harsh environment during transportation and handling;
(4) Fix the rub paper on the bottom rubber block of the load block with a clip;
(5) Fix the sample on the friction pad of the instrument test platform with the test surface facing the outside;
(6) Place the load block on the friction tester, turn it on, and set the number and speed of friction;
(7) Start the test, when the test reaches the set number of frictions, the instrument stops automatically;
(8) Remove the sample from the instrument base platform, check the damage of the printed layer, and analyze the amount of ink falling off the friction paper from the sample. The result is compared with the standard sample tested by the same method
Follow steps (3) ~ (7) to test each sample.
Test results and analysis
After the test is over, use the gloss meter or OD again to measure the color density of the severely rubbed ink layer on the sample, measure 3 points and take the average; divide the average density value of the sample after rubbing by the average density value before rubbing to get Ink layer abrasion resistance. The abrasion resistance of the sample ink layer tested in this experiment was 82%.
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