What is Tappi standard?
4.1. 1 TAPPI Standard Test Methods are testing procedures and related practices used in the measurement, evaluation, and description of pulp, paper, packaging, and related products, including raw materials used in their manufacture, use, or in scientific investigations of any such substances.
What is a Tappi lab?
The TAPPI analytical laboratory is temperature and humidity controlled space. The atmosphere is controlled to 50.0% +/- relative humidity and 23.0 +/- C for proper conditioning of samples per TAPPI method T402 sp-08.
What does Tappi standard t441 measure?
Scope. TAPPI T 441 Cobb Test describes a procedure for determining the quantity of water absorbed by nonbibulous paper, paperboard, and corrugated fiberboard in a specified time under standardized conditions. It is based on studies by Cobb and Lowe, Cobb and other investigators.
What is Cobb test for paper?
Cobb test (sized papers and paperboards)
The Cobb test determines the amount of water absorbed into the surface by a sized (non-bibulous) paper, paperboard, and corrugated fibreboard paper or paperboard sample in a set period of time, usually 60 or 180 seconds (Cobb60 or Cobb180). Water absorbency is quoted in g/m2.
What does TAPPI standard t441 measure?
What is Cobb value?
General information. The Cobb value provides information about the water absorption capacity of cartonboard samples. The Cobb test determines the amount of water that is taken up by a defined area of cartonboard through one-sided contact with water, within a certain amount of time.
How is Cobb value calculated?
To determine the Cobb Value, subtract the weight of the sample before testing from the weight of the sample after testing.
How is Cobb test calculated?
How is a Cobb test conducted?
Approx. 100 ml of water is poured into the cylinder. After 30 Minutes, the water is poured out. The specimen is weighed while wet and the amount of water absorbed by 1 m² of specimen material is calculated.
Why Cobb test is important?
The Cobb test is essential as it tests the ability of the paper to resist the penetration of water and quantity of water absorbed by the surface of fiberboard. If fiberboard absorbs too much water, the box may have difficulty maintaining strength and integrity.
What is unit of Cobb value?
The Cobb test determines the amount of water absorbed into the surface by a sized (non-bibulous) paper, paperboard, and corrugated fibreboard paper or paperboard sample in a set period of time, usually 60 or 180 seconds (Cobb60 or Cobb180). Water absorbency is quoted in g/m2.
What is the Cobb value?
The Cobb value provides information about the water absorption capacity of cartonboard samples. The Cobb test determines the amount of water that is taken up by a defined area of cartonboard through one-sided contact with water, within a certain amount of time.
How do you determine Cobb value?
Take the sample out carefully and use the roller to extract the extra amount of water. Weigh the sample. Now subtract the dry weight from the wet weight, the value you have is the Cobb value of Kraft paper. This the amount of water the sample absorbed in a defined time period.
Is standard for Cobb test?
paperboard, and corrugated fiberboard (Cobb test)
1 The standard test area is 100 cm2. If the available specimens are too small, a proportionately smaller test area may be used providing that the volume of water is reduced to provide a pressure head of 1 ± 0.1 cm. Other common test areas include 25 cm2 and 10 cm2.
What is Cobb factor?
The Cobb test determines the amount of water that is taken up by a defined area of cartonboard through one-sided contact with water, within a certain amount of time. Depending on the material, contact times of 60, 180 and 1800 seconds are common.