Paper and Board Strength Tests
Paper and board products are widely used in our daily lives. Sheet strength is critical to the performance of most grades, not only in their end uses, but also in converting and finishing operations. Because different paper and board grades are subjected to different stresses and strains, several different strength tests have been developed. The most common are tensile, burst, stiffness, tear, internal bond, and ring crush. This module will discuss common strength tests for paper and board grades, as well as sheet parameters that affect strength properties.
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Course Details
Learning Objectives
• Identify the organization whose standardized testing procedures are followed most often in the U.S. • Identify important factors to consider during sample collection and sample conditioning • Explain why paper and board sheet strength properties are important • Explain why it is important to keep track of the machine direction during sampling and testing • Describe tensile, TEA, stretch, burst, stiffness, tear, internal bond, ring crush, and SCT testing, including principles and units
Specs
Frequently Asked Questions
Why is sample conditioning important?
What factors can impact strength properties?
Why is it important to keep track of the machine direction for a sample?
What are the major strength tests?
What is zero-span tensile?
Sample Video Transcript
The tear test measures the force that is required to continue tearing a sample from an initial cut through a standard sample width. It is expressed in units of grams or millinewtons. There are several available test methods, but the most common uses the Elmendorf Tear Tester. With this tester, a sample strip is clamped in two places, and a slit is cut between them. A pendulum supporting one clamp is released, and it swings away from the other clamp, registering the force required to continue the tear as Elmendorf units on an arc scale. The tearing force can be calculated by multiplying the Elmendorf units by a factor. Fiber orientation greatly affects tearing resistance. So it is important to test and report CD and MD results separately.
