Scope

Procedures for determining tensile properties of paper and paperboard. Procedures given in this test method are for use with constant-rate-of-elongation tensile testing equipment, may be used with instruments designed for either vertical or horizontal operation. Procedures are applicable for all types of paper, paperboard, paper products and related materials within the measurement limitations of the equipment used. Properties that may be determined using this test method include tensile strength, stretch, tensile energy absorption, tensile stiffness, breaking length and tensile index. Values stated in SI units are to be regarded as the standard.

Safety

This standard does not address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Referenced Documents

ASTM Standards

Significance and Use

Tensile properties measured in this test method are fundamental properties associated with the manufacture, or end use, or both, of paper and paper products. They may be influenced by, or indicative of the type fibers used or the treatment of the fibers, or both, in a particular paper.

Tensile strength is indicative of the serviceability of many papers.

Stretch and sometimes-tensile stiffness are indicative of the ability of the paper to conform to a desired contour.

Tensile energy absorption is a measure of the ability of a paper to absorb energy at the strain rate of the test, and indicates durability of papers.

Tensile stiffness often gives a better indication of the mechanical response of the sheet to converting forces than do tensile rupture criteria.

Apparatus

	Tensile Testing Machine constant rate-of-elongation type conforming to the following: Two line contact grips/jaws for gripping the test specimens, with the line of contact perpendicular to the direction of the applied load & with means for controlling and adjusting the clamping pressure. The tensile testing machine must be capable of providing the measurement data required for making the calculations specified.
	Must be equipped with a load measuring device and a recorder which must be capable of accurate calibration. Must also be equipped with an elongation measuring device and recorder.
	Gear Drive

Alignment Jig

Planimeter or Integrator

Specimen Cutter

Magnifier and Scale or Similar Optical Comparator

Sampling

• Acceptance Sampling done in accordance with D 585
• Sampling for Other Purposes: sampling & number of test samples depends on purpose of testing. E 122 is recommended.

Test Specimens

• Ten (10) specimens in each of the two principle directions of the paper 25.4± 0.5 mm wide x 254 mm length
• Free of abnormalities as creases, holes, wrinkles or other features not typical of the paper

Calibration

• A specific calibration procedure for individual instruments is beyond the scope of this test method and must be obtained from the manufacturer of the equipment. Following are general considerations:
• Regularly inspect the machine for cleanliness, wear, misalignment, loose parts or damage
• Clean, grease or service machines at regular intervals
• Level machine accurately in the two principle directions using a carpenter's level
• Align clamping grips
• Position specimen grips 180 ± 5 mm (standard distance between the grip clamping zone0 test & measure the distance between the line clamp impressions produces on thin metal foil.
• Determine and adjust clamping pressure on specimen grips so slippage or specimen damage occurs.
• Weights used should have traceability to NIST. Deviation from true weight is ± 0.5%
• Periodic verification of the extension measuring system
• Perform other maintenance or calibration as required for proper performance.

Conditioning

• Samples in accordance with D 685
• Protect sample from extremes in humidity from the time of sampling until testing.

Procedure

1. Perform all testing in an environment specified in D 685
2. Adjust & calibrate testing machine
3. Specimen Width 25.4 mm
4. Effective Specimen Length 254 mm
5. Grip separation at start of test 180 mm
6. Nominal Specimen Length 254 mm
7. Rate of Grip Separation during Test 25.4 mm/min (this usually results in rupture in less than 30 sec and more than 10 sec.
8. Adjust data recording components for data recording as required for material being tested
9. Place one end of sample into one of the grips, align it and clamp it in place. AVOID HANDLING SAMPLE AREA THAT WILL BE BETWEEN THE CLAMPING ZONES.
10. Place other end of sample in the other grip. Carefully remove slack DO NOT STRETCH SAMPLE
11. Verify correct clamping pressure
12. Test ten specimens in each principle direction
13. Reject test value in which the test specimen: (a) slips in the jaws. (b) Breaks within clamping zone (c) show uneven stretching across its width (d) reject any test values for test specimens that break within 5 mm of the clamping zone (e) If more than 20% of specimens are rejected, reject all readings for the sample, inspect machine for conformance with specifications and correct
14. Record values for tensile strength
15. Record values for elongation
16. Record all deviations from procedure, particularly small sample length and the reason for they must be documented in the report

Calculation and Interpretation of Results

Calculate average value for tensile strength at rupture

Calculate average value for elongation at rupture

Calculate average value of tensile energy absorption prior to rupture. The following formulas may be use to calculate tensile energy absorption: TEA = 1 X 10^6 A/LW

= 9.807 X 10^4 A/LW = 175.1 a/lw

TEA = tensile energy absorption, J/m^2

If foot pound-force per square foot are desired use: tea = 12 a/w

To convert from tea to TEA use: TEA = 14.60 x tea

Calculate breaking length: BL = 102,00 (T/R) =3,658 (T/R)

Calculate tensile index: TI = 1000 (T/R) = 36.87 (T/R)

Following are the required units for tensile properties determined using this test method:

Tensile strength, kN/m

Elongation, %

Tensile energy absorption, J/m^2

Tensile stiffness, kN/m

Breaking length, m

Tensile index, N*m/g

Report

• Each test unit in each principle direction to 3 significant figures
• Average tensile strength and range or standard deviation
• Average percentage elongation and range or standard deviation
• Average tensile energy absorption and range or standard deviation
• The number of tests rejected and the reason for rejection
• Any deviations from the procedures specified.

Precision and Bias

• Repeatability within same lab
• Tensile Strength 5%
• Stretch 9%
• Tensile Energy Absorption 10 to 16 %
• Reproducibility different labs
• Tensile Strength 10%
• Stretch 25%
• Tensile Energy Absorption 22 to 36 %
• Bias: no statement made concerning bias

	Return
	To D828 Checklist