GB/T 12914-2018 Paper and board—Determination of tensile properties—Constant rate of elongation method(20 mm/min)
1 Scope
This standard specifies a method for measuring the tensile strength, strain at break and tensile energy absorption of paper and board, using a testing machine operating at a constant rate of elongation (20 mm/min). This standard also specifies equations for calculating the tensile index, the tensile energy absorption index and the modulus of elasticity.
This standard is applicable to all papers and paperboard except corrugated board.
Note: GB/T 22898-2008 Paper and board - Determination of tensile properties - Constant rate of elongation method (100 mm/min) (ISO 1924-3: 2005, MOD) specifies another form of constant rate tensile method, using a constant rate of elongation of 100mm/min and a test length of 100mm. The effects of elongation rate on tensile strength, strain at break, tensile energy absorption and modulus of elasticity are different for different test pieces. In most cases, the tensile strength increases by 5% ~ 15% when the elongation rate increases from 20mm/min (test length of 180mm) to 100mm/min (test length of 100mm). The test results obtained using the two methods respectively should not be compared with each other.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 450 Paper and board - Sampling for testing and identification of machine and cross direction, wire side and felt side (GB/T 450-2008; ISO 186:2002, MOD)
GB/T 451.2 Paper and board - Determination of grammage (GB/T 451.2-2002; eqv ISO 536:1995)
GB/T 451.3 Paper and board - Determination of thickness (GB/T 451.3-2002; idt ISO 534:1988)
GB/T 10739 Paper, board and pulps - Standard atmosphere for conditioning and testing (GB/T 10739-2002; eqv ISO 187:1990)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
tensile strength
maximum tensile force per unit width that paper and board will withstand before breaking under the conditions defined in the standard
3.2
tensile index
tensile strength divided by the grammage
3.3
elongation
increase in length of a test piece
Note: Elongation is expressed in millimetres.
3.4
strain
ratio of the elongation of a test piece to the initial test length
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
6 Calibration and adjustment of apparatus
7 Sampling and preparation of test pieces
8 Procedure
9 Calculation and report
10 Precision
11 Test report
Annex A (normative) Calibration of the tensile testing machine
