Sources, Origin and Properties Flashcards
How are paper and boards made?
made from pulp (mixture of cellulose fibres and up to 99% water)
cellulose fires are usually derived from finely shredded wood but other types of wood can be used such as hemp,bamboo
Wood gives the best result both deciduous and coniferous trees can be sued with soft wood being the most common
What is the process of pulp?
mechanical process converts debarked logs into fine chips which are then added to a chemical solution and cooked in large tanks under pressure to make the paper pulp
resulting fibrous liquid is then bleached or coloured
What is sizing?
liquid is then beaten with other chemicals or additives according to the required finish.
sizing stop the paper becoming super absorbent ,so it can be photocopied and printed.Paper with little sizing is very absorbent such as toilet tissue
How is pulp converted to paper?
pulp is fed onto a mesh conveyor belt which allows much of the water to drain away .
passes onto a serious of rollers which squeezes out any excess water
goes through drying rollers and onto a final set called calendar rollers
sometimes a final coating or sizing is added before the paper is cut
What are calendar rollers?
give the paper the desired finish eg satin or matt
Why should we recycle?
recycling paper and board is easy and the amount being recycled continues to rise
when paper is recycled it is graded
high quality glossy magazine produce higher quality paper products
twice as much is paid for recycled white office paper waste than cardboard
recycled paper uses between 40-70% less energy to produce than paper made from virgin pulp
What happens if discarded paper sent to landfills?
decomposes giving off green house gases called methane
What are the characteristic of tissue paper?
soft lightweight highly absorbent
What are the uses of tissue paper?
packaging for cosmetics and gifts
kitchen and toilet rolls
What does news print paper look like and what are its characteristics?
APPEAREANCE-off white thin slightly rough
CHARACTERISTICS-commercial printing of newspaper and some advertising leaflets
What does photocopy paper look like and what are its characteristics?
APPEAREANCE-usually brilliant ,white smooth CHARACTERISTICS-lightweight low costs good for laser printing toner
What are the uses of photocopy paper and photo quality paper?
PHOTOCOPY-photocopying and general use in home printer
PHOTO QUALITY-photographic printers,presentation printing ,greeting cards
What are the appearance and characteristics of photo quality paper?
APPEARANCE-brilliant white often coated on one side only ,very fine smooth finish
CHARACTERISTICS-high quality,holds ink well bright colours, quick drying ,gloss statin and and finish
What does carton board look like?
Natural brown or white coated or uncoated can by layered and be printed on one or both sides
What are the characteristics of carton board
thick to very thick when layered
can be coated or foil lined to hold food and liquids full colour printing possible
