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Paper and Paperboard Properties and Tests

1. What is the difference between material tests and package performance tests?

Material tests tackle the material in isolation while package performance tests identify the properties of the material.

A. How does their difference differ?

They differ in their aims since they are performed to test for different things.

2. What do the acronyms TAPPI, ASTM, ISO mean?

TAPPI- Technical Association for the Pulp and Paper Industries, ASTM-American Society for Testing and Materials and ISO- International Standards Organization

3. What standards of organization is the most important source of tests for the properties of paper and paperboard?

TAPPI standards are the most important source.

4. What is the principal difference between ASTM and ISO?

ASTM focuses more on plastic material and performance tests while ISO concentrates on paper products.

5. What is the difference between repeatability and reproducibility in test standards?

Repeatability is the maximum difference that can be obtained 95% of the time the times are done in the same laboratory with the same material in a short period. Reproducibility is the estimated difference in the results obtained 95% of the time when the tests are done by two different laboratories.

6. What is the difference between accuracy and precision?

Accuracy means that the values obtained are very close to the actual values while precision refers to the ability of the tests to be more repeatable and reproducible.

A. What is bias?

It is an inclination to a particular opinion without a valid basis but rather out of personal preference.

7. In general, what is the thickness borderline between paper and paperboard?

Thickness of over 10 points is a paperboard while below it is paper.

8. How is paperboard caliper expressed in U.S. units vs. metric units?

In U.S. units, it is expressed as a thousandth of an inch. Alternatively, it is expressed in microns.

9. How thick is 24-point board in microns?

609.6 microns

A. How thick is 600-microns board in points?

23, 622.05 points.

10. What is the range of thickness most common for paperboard?

12-24 points is the most common range.

11. Is it more common to specify paperboard by thickness or basis weight?

By basis weight

A. Which is more common for paper?

Basis weight or grammage

12. How many square feet is the basis for paper versus paperboard?

3, 000 square feet

A. How many square feet are required for containerboard?

1, 000 square feet

13. What is the basis weight?

BW= 29. 075 Ibs

A. What is the grammage?

47.319 g/m²  

14. What is the weight of two box liners?

Weight = 0.252 Ib

A. What is the cost of the two liners?

0.0441 dollars

15. What is relative humidity relative to ?

It is relative to the amount of moisture the air can hold

16. What is the original moisture content of the paper?

About 10%

17. Why is wood moisture content calculated on a dry basis and paper on a wet basis?

Because it is more convenient when calculating the pulping chemicals required.

18. What is the general moisture content of paper at 50% RH?

About 5%

19. What is the ideal range of the moisture content of paper?

3-7 % is the ideal range

A. Below what content does the paper become brittle?

Below 3 %

B. Above what content does it lose its stiffness?

Above 7 %

20. What are standard TAPPI temperature and RH conditions and why are they used?

5% of the 50 % RH. They are used because they test for the paper’s properties at its best

21. Why should a paper-based sample be preconditioned in drier conditions first?

Because it gives, the papers a moisture content nearly the same as 60% conditioning.

22. What are the temperature and RH for ASTM’s standard tropical conditions?

40 degrees Celsius and 85% RH

23. How is tensile strength, elongation at break, stiffness and tear strength affected by an increase in moisture content?

It will cause a decrease in the above properties.

24. What optical properties are most affected by aging?

Whiteness and brightness of the paper

25. What is more commonly specified in packaging; whiteness or brightness?

Brightness

A. What is the difference?

Whiteness is the color of the sheet of the paper while brightness is the reflecting ability of the paper.

26. What is the most common brightness value specified for SBS and clay coated paperboard?

70 bright

27. What is meant by opacity and gloss?

Gloss is a measure of the reflectance of the light from the paper’s surface while opacity is the level by which light is not allowed to travel through the paper.

28. What is the WVTR?

83.33 g/m ² d

30. In which direction will a paper wetted on one side curl?

Paper has a more feathery appearance when torn parallel to the MD. The axis is the dry surface while the side out is the wet side

31. What are the tensile strength and the percentage elongation?

Tensile strength = 13 Ibs/ inch, % elongation = 1.43%