The "ISO 1924 Paper and cardboard - Determination of shrinkage properties" standard, published by the International Organization for Standardization (ISO), consists of the following sub-sections published under the same title:
The method for determining tensile strength described here is related to the method specified in the ISO 1924-2 standard. This method uses a testing device that operates with a constant tensile force application rate (constant loading rate) causing the test piece to fracture within an average of 20 seconds plus/minus 5 seconds. The method described in the ISO 1924-2 standard uses a device that operates with a constant elongation rate.
The device class in this standard is being replaced by the device class in the ISO 1924-2 standard. Therefore, considering that a significant number of devices operating at constant load speeds are still in use, it is recommended that the ISO 1924-1 standard be repealed 10 years after its publication.
In principle, during testing, a test specimen of specific dimensions is stretched at a constant loading rate until fracture occurs, using a tensile testing machine that measures tensile strength. The maximum tensile strength is recorded. Based on the results obtained and the sample's weight, the fracture length and tensile index can be calculated.
Samples are selected according to ISO 186 standard. They are conditioned according to ISO 187 standard, and tests are performed by preparing the test pieces under the same atmospheric conditions used in the conditioning of the samples.
Tests conforming to this standard always involve the measurement of tensile strength. The measurement or calculation of other properties is subject to agreement between the parties involved.
This standard applies to all papers and cardboards, including those with high tensile strength at break, provided the results are within the capacity of the testing machine. It also applies to the components of corrugated cardboard, but not to corrugated cardboard itself.
This standard does not apply to paper tissues and paper tissue products for which the ISO 12625-4 standard is valid. For determining the tensile properties of laboratory plates, the ISO 5270 standard is recommended.
The method for determining tensile properties specified in this standard is the most commonly used method. This method is related to the method specified in the ISO 1924-3 standard. While the applied constant elongation rate is 20 mm/min in the ISO 1924-2 standard, it is 100 mm/min in the ISO 1924-3 standard.
Since the results of the tensile test depend on the applied elongation rate, ISO 1924-2 and ISO 1924-3 standards do not yield the same results. The rate dependence can vary depending on the paper quality and is different for tensile strength, strain at break, tensile energy absorption, and modulus of elasticity.
In most cases, increasing the elongation rate from 20 mm/min (180 mm test span length) to 100 mm/min (100 mm test span length) can increase tensile properties by 5 to 15 percent.
In principle, during testing, a test specimen of specific dimensions is stretched at a constant elongation rate until fracture, using a testing machine that records both tensile force and, if necessary, elongation. If the tensile force and elongation are continuously recorded, the strain at fracture, tensile energy absorption, and modulus of elasticity can be determined. From the recorded data and the weight of the specimen, the tensile index and tensile energy absorption index can be calculated.
If tests are being conducted to evaluate a batch, the sample should be selected in accordance with ISO 186. If tests are being conducted on another type of sample, it is necessary to ensure that the samples taken are representative of the sample being tested. Paper and cardboard samples are conditioned in accordance with ISO 187. Samples are kept in the conditioning environment throughout the test.
This test, like other mechanical tests, is very sensitive to changes in the moisture content of the test piece. Test pieces are handled carefully, and contact with the portion of the test piece to be placed between the clamps should be avoided with bare hands. Test pieces are kept away from moisture, heat, and other influences that could alter their moisture content.
When determining tensile strength, a higher accuracy in elongation measurement is required compared to determining other tensile properties. If elongation is determined with lower accuracy, the resulting tensile strength value does not conform to this standard. This standard applies to all papers and cardboards, including papers with high extensibility such as crepe papers and extensible burlap papers, but excludes low-density papers such as tissue papers and tissue products as recommended by the ISO 12625-4 standard.
The ISO 1924-3 standard was developed to specify the conditions for determining the tensile properties of paper, including tensile stiffness and tensile stiffness index, using a higher elongation rate than that specified in the ISO 1924-2 standard, which is the most commonly used section where tensile strength, elongation at break, tensile energy absorption, and modulus of elasticity are measured. In the ISO 1924-2 standard, tensile properties are measured at a constant elongation rate of 20 mm/min in a test opening of 180 mm. For the measurement of tensile stiffness in the ISO 1924-3 standard, a higher accuracy in recording elongation is required compared to the ISO 1924-2 standard.
The ISO 1924-3 standard specifies the faster of the two methods. In addition to the properties measured in the ISO 1924-2 standard, tensile strength is also measured. Tensile properties are measured at a constant elongation rate of 100 mm/min in a 100 mm test opening, and the elongation is recorded with a higher accuracy than in the ISO 1924-2 standard.
The ISO 1924-3 standard differs from existing standards for testing tensile properties in that the test interval, i.e., the distance between compression lines, is 100 mm, regardless of the type of specimen being tested. To shorten the test time and thus enable testing a larger number of specimens within a given period, the elongation rate has been increased to 100 mm/min.
In principle, it is not possible to predict the exact relationship between the results of tensile tests of any paper whose tensile properties are determined using ISO 1924-2 and ISO 1924-3 standards. This relationship can only be determined through laboratory tests.
For many years, our organization, with its competent and experienced staff, has been understanding the needs of its customers, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "ISO 1924 Paper and cardboard - Determination of shrinkage properties" standard.
To get an appointment, to get more detailed information or to request an evaluation, you can ask us to fill in our form and reach you.
