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The density can be calculated by dividing the grammage of paper (in grams per square metre or "gsm") by its caliper (usually in micrometres, occasionally in mils). [1] The "ISO 534:2011, Paper and board — Determination of thickness, density and specific volume" indicates that the paper density is expressed in grams per cubic centimeter (g/cm ...
Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing the area density of a paper product are commonly used: Expressed in grams (g) per square metre (g/m 2), regardless of its thickness [1] (known as grammage). This is the measure used in ...
Set-off is measured at two different time intervals, 0.35s and 3s. A freshly printed surface is pressed against a paper after 0.35s and after 3s. Then the set-off density is measured. The idea behind selecting these two timings is to know what will be the set-off when the materials are used in a high-speed press and a low-speed press.
Machine-finished coated paper (MFC) has a basis weight of 48–80 g/m 2.They have good surface properties, high print gloss and adequate sheet stiffness. MFC papers are made of 60–85% groundwood or thermomechanical pulp (TMP) and 15–40% chemical pulp with a total pigment content of 20–30%.
The telephone cables have a large number of conductors that are individually insulated. The paper needs to be thin (30-40 g/m 2). A normal power cable needs more insulation and therefore paper with higher paper density is used, normally 60-190 g/m 2. The paper needs to be strong, elastic, uniform and free of holes or debris.
These are made by the reaction of phenols, formaldehyde and primary amines which at elevated temperatures (400 °F (200 °C)) undergo ring–opening polymerisation forming polybenzoxazine thermoset networks; when hybridised with epoxy and phenolic resins the resulting ternary systems have glass transition temperatures in excess of 490 °F (250 °C).
In the 1980s started the commercialization of air-laid paper, which gave better bulk, porosity, strength, softness, and water absorption properties compared with normal tissue paper. Also in the 1980s started the use of superabsorbents in diapers and reduced the need for fluff pulp and is now down to 15 grams or even less.
Thermal paper (often supplied in roll form, and sometimes referred to as an audit roll) is a special fine paper that is coated with a material formulated to change color locally when exposed to heat. It is used in thermal printers , particularly in inexpensive devices such as adding machines , cash registers , and credit card terminals and ...