Tensile Strength Tester for Paper and Board

What is the Tensile Strength Tester for Paper and Board?

A tensile tester stretches a conditioned paper strip at a constant rate and records breaking force, elongation and tensile energy absorption. It is the fundamental strength test for packaging, sack and label papers and for board.

Overview

The specimen is clamped between two grips separated by a defined test length, commonly 100 or 180 mm, and stretched at a controlled rate until it breaks. A load cell records the force, and an extensometer or the crosshead displacement gives elongation, from which tensile index, stretch and tensile energy absorption are calculated using the measured basis weight and width. Grips are lined with a material that prevents slippage without cutting the specimen, and jaw pressure must be set so that failures occur in the free length rather than at the grip line. Many instruments also offer wet tensile testing with a wetting device, compression testing for corrugated board and, with suitable fixtures, internal bond testing on a perpendicular pull, which makes a single frame useful for several specification tests.

How does it work?

Mechanical paper tests apply a controlled force or deformation to a conditioned specimen and record the load or the extent of damage. Tensile testing pulls a strip at constant rate and records breaking force, elongation and tensile energy absorption, from which indices are calculated using basis weight. Tearing resistance is measured by the energy absorbed when a specimen with a pre-cut slit is torn by a pendulum or a falling weight. Folding endurance counts the number of double folds a strip withstands under tension before it breaks. Surface and absorbency tests use different principles: water absorbency is determined by the mass of water taken up by a defined area during a timed contact, smoothness by the air flow between a measuring ring and the sheet surface, and porosity by the air flow through the sheet itself at a defined pressure difference.

What are the key features?

• Constant rate of elongation drive
• Load cell with automatic force calibration
• Test lengths of 100 and 180 mm
• Wetting device for wet tensile testing
• Elongation and energy absorption calculation
• Optional compression and internal bond fixtures

What are the technical specifications?

A typical tensile strength tester for paper and board configuration offers maximum force of 500 N or 1000 N, force resolution of 0.01 N, test length of 100 mm and 180 mm, stretching rate of 1–500 mm/min, 20 mm/min typical, specimen width of 15 mm or 25 mm and elongation measurement of To 100% or more. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Tensile Strength Tester for Paper and Board is used in tensile strength of packaging and sack papers, board tensile and stretch verification, wet strength of kitchen and industrial papers and runnability assessment for printing and converting. Across the wider Paper Quality Analysis class, laboratories also deploy it for tensile strength and elongation of packaging papers, tearing resistance of sack, tissue and bound papers and water absorbency of sizing and coating grades.

Which standards and certifications apply?

Relevant standards and methods include ISO 1924-2, ISO 1974, ISO 535, ISO 8791-2, ISO 5626, ASTM D828, TAPPI T494, TAPPI T414, TAPPI T441 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Condition specimens to the standard atmosphere, usually 23 °C and 50% relative humidity, before every mechanical test, because strength properties change sharply with moisture. Cut specimens with sharp dies or blades and reject those with damaged edges, since a nick initiates premature failure. Keep grips clean and aligned, and verify load cells with certified masses or a reference load cell at defined intervals. For absorbency and surface tests, control the water temperature, contact time and pressure difference, and clean measuring rings and plates, because deposits change the flow. Record basis weight, test direction, specimen count and conditioning with every result so that indices can be recalculated.

How do I select the right Tensile Strength Tester for Paper and Board?

Select a tensile tester when the specification names breaking force, tensile index, stretch or tensile energy absorption, and confirm the test length, rate and grip width match the standard. Add a wet tensile device if the product is used wet, and check the force resolution against the lightest grade you test.

How does it compare with other Paper Quality Analysis variants?

Select the test that corresponds to the specification you must meet and to the failure mode you are investigating. Tensile testing is fundamental for packaging, bag and label papers because it defines strength in the principal load direction. Tearing resistance is important for papers that are handled, punched or bound, and for tissue and sack grades. Internal bond, folding endurance and tensile energy absorption matter for papers that are creased or repeatedly flexed. Water absorbency is specified for papers that are glued, coated or used outdoors, while smoothness and porosity are specified where print quality and ink penetration matter. Each instrument should be capable of the exact conditions named in the standard, since test length, strain rate and contact area change results appreciably.