The classification of leather is quite complicated. According to the tanning method, chrome tanned leather, vegetable tanned leather, oil tanned leather, aldehyde tanned leather and combined tanned leather can be included. According to different levels, there are first-layer leather and second-layer leather. The first-layer leather includes full-grain leather and trimmed leather; the second-layer leather includes pig second-layer leather and cattle second-layer leather. In addition to the above classification methods, as there are many types of leather materials, we are generally more accustomed to classifying them according to their types. Mainly divided into two kinds of natural leather and substitute leather. Natural leather is what we call 'leatherSubstitute leather is what we call 'fake leatherBecause synthetic leather or other leather-like products are actually artificially synthesized products from basic chemical raw materials. Judgment method and test method of leather abrasion resistance: The abrasion resistance of leather is the characteristic of resistance to abrasion of leather. Leather wear is an important cause of leather damage. Although the wear fastness of leather has not yet been assessed as a national standard, the wear resistance test of leather is still indispensable to measure its quality. It has extremely important significance for assessing the fastness of leather. Judgment method: There are two methods for judging the leather wear resistance index, namely the end point method and the appearance change method. 1.1 End point method: The number of rotations required to grind off l mm leather is the thickness index of wear resistance, and the number of friction rotations is recorded as the index of wear resistance. 1.2 Appearance change method: After the test sample has been rubbed for a certain number of times, observe its appearance change, such as color change, degree of wear and other appearance changes as an indicator of wear resistance. Test method 1. Reference standard for the flat grinding method: 'GB/T 21196-2007 Martindale Method for the Determination of Abrasion Resistance of Fabrics'. Test equipment: There are many types of fabric flat grinding machines. At present, the Martindan tester is the most used in the testing industry. Therefore, the flat grinding method is often referred to as the MARTINDALE friction
testing machine method. Test principle: The circular sample installed in the sample holder of the Martindale Abrasion Tester is rubbed with the abrasive material (ie standard fabric) by the plane motion of Lisharu (Lissajous) pattern under the specified load. The sample holder can rotate freely around its axis perpendicular to the horizontal plane. Determine the wear resistance of the leather according to the total number of times of friction of the sample damage. Test method: During the test, the test sample of a certain size is in contact with the standard abrasive under the specified pressure, and the sample is moved relative to the abrasive in the Li Sharu track, so that the test sample is uniformly abraded in multiple directions. 2. The reference standard of Taber abrasion method: 'GB/T 2726-2005 Determination of the abrasion resistance of leather physical and mechanical tests'. Test instrument: TABER wear resistance testing machine Test principle: pre-grind 25 revolutions, put the tested sample on the level platform of TABER wear resistance testing machine to rotate, two grinding wheels are given specific pressure to press on the test piece. , The axis of the grinding wheel is parallel to the horizontal plane, one grinding wheel is facing outwards, and the other is facing inward. In a certain period of time, all changes of the test piece are recorded. Test method: Use a cutter to cut a sample with an outer diameter of 108mm and an inner diameter of 8mm. Then stick a hard sticker of the same size on the back of the sample. Place the center hole of the sample on the rubber pad of the screw, cover the pad, and fix the sample with a compression nut. Then put on the fixing ring, and tighten the fixing ring screws with a wrench. Install two H18 grinding wheels on the support arm. Each grinding wheel exerts a force of 250±10g on the sample to be tested. Make sure that the side with the label is facing outwards so that the weight of the grinding wheel is 500g. Connect the vacuum cleaner to the vacuum cleaner. Connect the tube to the connector on the left side of the machine and start the vacuum cleaner. Set the number of tests according to the standard, and set the rotation speed to 72 revolutions. Then start the start button, turn on the instrument with a rotation speed of 60±5 times/min, rotate it horizontally, and perform the test as required. In the test, use a brush to remove the attachments on the sample surface, observe the wear of the test, grind the leather to the specified end point, and record the final number of revolutions. It is not meaningful to compare the test results obtained by testing different materials and using the same experimental method, but the conclusions drawn from these results are consistent. Therefore, any method can independently quantify the wear resistance of the material. In general, the material of natural leather is softer, so its wear resistance is poor. Coated leather has a hard texture and is not easy to wear, so it has better wear resistance.
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