Definition
Paper breakage meter is a special testing equipment used to determine the breaking strength of paper and cardboard. Bursting strength refers to the maximum pressure perpendicular to the surface of the specimen that paper or cardboard can withstand per unit area, expressed in kilopascals or pound-force per square inch. This index is an important physical parameter to evaluate the ability of paper, cardboard and its products to resist external pressure and impact during transportation, processing and use, and is widely used in the field of quality control of packaging materials, printing paper and industrial paper.
Principle
The working principle of the paper breakdown meter is based on the hydrostatic pressure test method. The core components of the instrument include a ring clamp and a flexible rubber membrane. During testing, the specimen is securely clamped between the ring clamps, creating an enclosed area. The instrument is driven by a hydraulic or pneumatic system that expands the rubber film at a uniform rate, thus applying uniform and vertical pressure to the specimen. The pressure continues to increase until the specimen ruptures, and the sensor records the maximum pressure value at the moment of rupture in real time, which is the bursting strength of the specimen. The entire testing process follows the conditions specified by standards such as ISO 2758, GB/T 454 and TAPPI T403.
Measurement method
Standard measurement methods usually involve the following steps: First, the specimen is pretreated under standard temperature and humidity conditions. The specimen is then placed flat in the instrument gripping area to ensure that it is wrinkle-free and evenly clamped. Start the test program and the rubber film begins to expand and apply pressure. The system automatically records the bursting strength value and calculates the average value and coefficient of variation of multiple specimens as needed. The measurement results are analyzed in combination with the quantification (gram weight) of the specimen, and sometimes the breakage resistance index is calculated, which is formulated as:P = p / g, where P represents the bursting resistance index, p represents the measured bursting strength, and g represents the quantification of the specimen.
Influencing factors
The bursting strength of paper is affected by various factors. The length, strength, and bonding strength of raw material fibers are fundamental factors, and usually long fibers provide higher bursting strength. The degree of beating in the production process affects the tightness of the fibers, which can change the strength. The quantitation and thickness of paper tend to be positively correlated with bursting strength, but not absolutely linear. Ambient temperature and humidity can also affect test results, as the moisture content of fibers can change their flexibility and bonding state. In addition, the uniformity of the specimen grip and the rate of pressurization during the test may also lead to measurement deviations if they do not comply with the standard.
Applications
The application of paper breakdown meters is mainly focused on quality control and research and development. In the packaging industry, it is used to evaluate the resistance of packaging materials such as corrugated cardboard and containerboard to breakage during actual stacking and transportation. In the paper industry, it is a regular tool for monitoring the physical properties of products during production. The printing industry uses burst resistance tests to ensure that paper does not crack during high-speed printing. In addition, the instrument is also used to evaluate the performance of special papers, such as sandpaper base paper, cable paper, and other industrial papers.
Equipment selection considerations
When choosing a paper breakdown meter, multiple technical parameters need to be comprehensively considered. The measurement range should cover the expected intensity value of the sample to be tested, with a margin. The accuracy and resolution of the instrument must meet the requirements of the relevant standards for laboratory-grade equipment. Whether the pressurization rate control is accurate and stable is the key to ensuring the comparability of test results. The clamp size must comply with the applicable standards, and the common clamp inner diameter is 30.5 mm. The equipment should have good data management capabilities and be able to store and output test results. At the same time, it is necessary to confirm that the instrument meets specific international, national, or industry standards followed by the target market or industry. The user-friendly design of operation, ease of maintenance, and the technical support capabilities of suppliers are also important considerations for long-term use.