Tensile strength of paper

What is the tensile strength of paper?
The tensile strength is the maximum stress to break a strip of paper sheet. It is one of the most important basic physical properties of paper and paperboard. The tensile strength is different basis on fiber direction. Since the fiber orientation is dissimilar between machine direction (MD) and cross direction CD), hence the tensile strength is measured in both directions. Machine direction is the direction of the paper web which is running on the machine whereas cross direction means the direction, which is perpendicular to the paper sheet that is running on the machine during paper making. It is greater in machine direction than in cross direction. It is calculated with the force per unit width and express as N/m.

The tensile strength test of paper sheet is like to the other materials test, but the method of expressing is different. For most cases the tensile strength is generally expressed in terms of load per unit cross-sectional area, whereas in paper industry it is stated in terms of load per unit of the test specimen. If the tensile strength of paper is lower, then the quality of the paper is lowered and it in need to be increased by improving different factor.

Relation of the tensile strength of paper

Tensile strength is used to find out how resistant paper is to a web break. The strength, length and bonding of fiber, degree of fiber refining and the direction of the fiber are the main sources of the tensile strength of paper. It is also depends on the quality and quantity of fillers used. It is a significant factor for many applications as like printing, converter and packaging papers.

Tensile index and its calculation
Tensile index is defined with tensile strength divided by basis weight and express as Nm/g.
Tensile Strength = N/m
Basis Weight = g/m2
Hence, Tensile index (TI) = (N/m)/(g/m2 ) = Nm/g

Tensile strength test machine

Several types of tensile strength testing apparatus are available, working on horizontally or vertically oriented specimen. There are five types of tensile strength tester apparatus used in paper industry such as rigid crosshead type, inclined plane type, hydraulic type and spring type. Among them pendulum type tensile strength test is most commonly used.

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19 Responses to Tensile strength of paper

  1. Muhammad Saleem Malekzadeh says:

    I am very keen to learn more about Paper & Pulp. What should be the minimum and maximum Tensile strength of Kraft liner board?
    How is Cobb of a kraft paper tested? What is Cobb TS & BS? What should be the minimum and maximum SCT of a Kraft Liner board?

    I will appreciate if there is any short courses available so that I could join to learn more.

    Thanks & best regards

  2. Pranav manjunath says:

    Dear saleem,

    Tensile strength depends upon the type of paper. Upto my knowledge cobb can be tested by pouring water on the paper and checking the dewatering of it up to 45 to 60 sec of minimum time. If the water or moisture detected at the lower end of paper, then the quality of the paper is not upto expected regarding kraftliner paper. T. S the breaking or tearing point of a paper when maximum force is applied to tear it. That max force noted as T.S of paper can be tested by machines. B.S. Can be checked as same above. It is the maximum burst strength factor which the produced paper can with stand

  3. Jenny Ajoc says:

    Is there any way to manually measure the tensile strength of paper? We are conducting an investigative research about the relationship between the the strength of paper made from carabao grass and its relative “cooking” time. It would mean a lot to our study. Thank you!

  4. r.k.saxena says:

    if tensile strength of a paper is 98N/15mm, what would be in MPa

    • Sachin says:

      I am looking for same answer …

      Have you figured it out ??

      • admin says:

        1MPa = 1000000Pa = 1000000 N/m2
        Now you can calculate easily

        • Sachin says:

          Thanks for your reply,
          Tensile strength of paper is expressed in N/m (Force per unit length) everywhere.
          I am looking for a way to convert the tensile strength of paper to N/m^2 (Force per unit area).

          I assume this is because the paper strength might not be proportional to its cross sectional area. It should calculated separately for each paper weight

        • Raju says:

          if tensile strength is 0.521 Mpa then what would be in N/m.
          Width =50.8 mm
          could u please calculate and advice

    • Rashi raikwar says:

      Sir plz calculate the tensile index of white printing paper….grammmage 59.2 g/m2
      Tensile strength 33.58 n/mm2

  5. r.k.saxena says:

    if tensile strength of a paper is N/15mm to MPa.

    Thanks & regards

  6. Satish Kamble says:

    Can we run machine speed at more than papers breaking length. Both while paper making and converting operations?

  7. what the standard tensile , tear , burst and folding for writing and printing paper in N/m , mN , kPa , N0 and what is the standard tear index for 60 g/m2 in N m/g , mN m2/g , kPa m2/g respectively .
    Best regards

  8. Junianto Yuristiono says:

    Dear Sir

    We are looking for Tensile Strength Tester for Paper and Plastic to be used in Laboratory
    Please quote qty 1 pc
    Kindly give catalogue and data sheet
    Our company is PT Adika Safeta Tunggal in Indonesia


  9. Lari says:

    I need to find the force to punch 100 sheets of A4 size paper using a 5mm dia pin. If the punching force calculation is perimeter x thickness x shear strength. How much is the shear strength of the paper?

  10. Vijay says:

    I need to understand that why do VFD supplier propose “MultiDrive” configuration i.e.with common DC source especially for dryer section.

    Is there some kind of regeneration taking place in dryer section during running?
    if yes,how do we calculate it to calculate ROI?


  11. Meet says:

    what is The Tear Index of JK Easy Copier Paper.(A4) 70gsm?

  12. Arif Hussian says:

    Can any one confirm if the tensile of MD is lower and CD wise its OK, then how we can improve it on machine.

  13. Chue says:

    How to convert MPa to N/m?
    Please help me!!!!

  14. iiiiiiesha says:

    Hello may I ask, what is the standard level of tensile strength of a paper, how do we consider if its strong or weak? Thank you very much

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