paper and cards Flashcards
what is external sizing
sizing are chemical agents added to the pulp to increase strength and reduce absorbency.
how does internal sizing affect how it is manufactured
sizing helps the paper run through the machines more smoothly
what factors can make the perfect piece of paper (4 marks)
the source of cellulose fibres
the fillers
the sizing agents
the calendaring process
additional finishes
what are the best source of cellulose fibres for paper and why
from wood due to quality of the fibres length and strength
what type of wood is used for paper and why
coniferous trees ( soft woods ) fast growing and the fibres are longer and stronger
what are the 6 characteristics that are seen in paper
whiteness
opacity
strength
absorbency
finish
cost
what are the 6 sources of cellulose fibres
flax
hemp
straw
cotton
bamboo
and most commonly wood
what is lignin
the natural substance that bonds the cellulose fibres
what are the two main coatings
clay which increases smoothness
polyethylene which increases glass and strength
what does uncoated paper allow for
allows for greater and faster absorption of ink or water
what are the 4 strength factors that affect the paper
the way the cellulose fibres bond to each other
the strength of the cellulose fibres
the length of the cellulose fibres (longer being stronger)
the quantity of fillers used (more fillers mean less strength)
what equipment is used for testing the strength of paper
the Elmendorf tear test
how does Elmendorf’s test work
a pendulum tears the sample and continues to a resting position which is noted on a scale in Elmendorf’s units
what is another way to measure the strength of a paper or board
impact testing or transportation testing i.e transport objects and review the results
what is die cutting
a large jig used to manufacture paper and boards in mass production
