Abstract : Folding resistance refers to the ability of paper and paperboard to resist folding fatigue strength, usually related to the tearing degree of paper. The factors determining the folding resistance of paper and paperboard generally include the length, strength, flexibility and bonding force between the paper fibers. The long, strong and firmly bonded fibers are often made of paper with high folding resistance. If softwood pulp or grass pulp is added to the softwood pulp, the folding resistance is significantly reduced. In addition, the influence of the basis weight, thickness, tightness and moisture content of the paper on the folding resistance is also large . This paper takes Jinan Saicheng's self-developed " NZ-01 Folding Tester " as an example, and conducts a special test on the folding resistance of paper produced by a certain manufacturer, and through detailed records of the test process and test results, Provide a reference direction and method for the majority of enterprises in need. Keywords : paper, paperboard, folding resistance, folding fatigue strength, folding resistance tester, paper folding resistance instrument, cardboard folding resistance instrument, paper folding instrument manufacturer, MIT folding instrument, MIT folding Degree tester The folding resistance is very meaningful for reflecting the performance of paper bag paper and carton lining paper. Any paper that needs to be folded frequently when used generally has strict requirements on the folding resistance. For example, boxboard requires a high degree of folding resistance, which can easily lead to damage during transportation. In addition, there is a certain requirement for the folding resistance of general cultural printing papers such as tracing paper, writing paper, letterpress printing paper, book paper, and wrapping paper. Otherwise, it is easy to cause the printed characters and pictures to become blurred. Affect people's perception. The folding resistance specified in the national standard refers to the standard width of the sample, that is, the logarithm of the number of double folds required to reciprocate under certain conditions until breaking (base 10). It seems to be a very complicated process, but in fact, with the help of precise testing instruments, the whole testing process is very simple. As one of the basic mechanical properties of paper, the index of folding resistance will directly determine whether the products of its manufacturers are qualified, and whether it can withstand the test of the market after being put into use. Therefore, manufacturers have very good resistance test for paperboard. necessary. 2 , the implementation of standards GB/T2679.5-1995 "Determination of folding resistance of paper and paperboard (MIT folding resistance method)", GB/T457 "Determination of folding resistance of paper and paperboard", ISO 5626 "Determination of paper folding resistance" Cardboard produced by a manufacturer ( Note: This sample is provided by customers of Jinan Saicheng ) The “ NZ-01 Folding Tester †independently developed by Jinan Saicheng has met many national and international standards: ISO 5626, GB/T 2679.5, QB/T 1049. 4.1 Detection principle The paper or paperboard can withstand a double fold of 135° reciprocating under a certain tension, and the number of double folds of reciprocating folding or the number of double folds based on 10 is expressed as a logarithmic value, and the number of times used for breaking is recorded. 4.2 Application range Basic application: Paper Suitable for measuring the folding fatigue strength of paper and paperboard with a thickness of 1mm or less. cardboard Extended application: aluminum foil Suitable for measuring the folding fatigue strength test of copper foil in the electronics industry with thickness less than 1mm. Copper foil 4.3 technical parameters Measuring range: 1 to 99999 times. Folding angle: 135±2° Folding speed: 175±10 times/min Folding head width: 19±1mm Folding radius: 0.38±0.02mm Spring tension: 4.91 ~ 14.72N, each tension of 9.81N, spring compression of at least 17mm Clamping distance: 0.25, 0.50, 0.75, 1.00 mm. Dimensions: 310mm (L) X360mm (B) X420mm (H) Weight: 25 kg 5 , the testing process (1) According to the standard, at least 10 longitudinal and transverse specimens with a width of 15 + 0.1 mm and a length of not less than 140 mm are cut. (2) Clamp the specimen vertically between the two clamps of the folding head and repeat the adjustment to ensure that the spring tension pointer is at the desired position. (3) Start the instrument and start reciprocating until the sample is broken. It should be noted that half of the sample is folded to the front. (4) Read the force value displayed by the instrument when it is broken. After the instrument is automatically homed, the next half of the test is performed. (5) Repeat the above test, test 10 samples in the vertical and horizontal directions 6 , test results (1) Repeatability (same laboratory) when the folding endurance value is about 1.5, the repeatability is about 8%; the folding endurance value is about At 3.5 , the repeatability is about 2%. (2) When the reproducibility (interlaboratory) folding resistance value is about 1.5, the reproducibility is about 10%; the folding endurance value is about At 3.5 , the reproducibility is about 4%. 7 , conclusion With its advanced photoelectric control technology, “ NZ-01 Folding Tester †has the advantages of more accurate data, higher test efficiency, automatic result storage and output printing on the test of folding resistance of paperboard. The user's operation and analysis of the results is a professional high-precision and high-efficiency instrument that the manufacturer deserves to choose and trust. In addition, in addition to folding resistance, indicators such as bursting resistance, compressibility, compressive strength, and abrasion resistance are also indicators that must be measured by manufacturers for paper and paperboard. Jinan Saicheng is a modern high-tech enterprise integrating R&D, manufacturing, sales, training and service. Since its establishment more than ten years ago, it has developed nearly one hundred instruments, which can simultaneously meet the different testing indicators of customers for the same product. Improve work efficiency. For more questions about the instrument, please call Jinan Saicheng Technology directly! Examination Nitrile Gloves,Nitrile Gloves,Powder Free Hand Gloves,Disposable Examination Nitrile Gloves Puyang Linshi Medical Supplies Co., Ltd. , https://www.linshihealths.com
Test method and solution for paperboard folding resistance
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