week 10 notes
week 10 notes GC440
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This 0 page Class Notes was uploaded by Allie S on Sunday November 1, 2015. The Class Notes belongs to GC440 at Clemson University taught by Dr. Weisenmiller in Summer 2015. Since its upload, it has received 47 views. For similar materials see Commercial Printing in Graphic Communications at Clemson University.
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Date Created: 11/01/15
Week 10 run 11022015 Paper must acclimate to its environment about 24 hours before a press 0 Grain direction when a sheet is being manufactured will align in a single direction long or short Paper terms Tensileincreased by beating and re ning Folding and burst strengthincreased by beating and re ning Tear strengthdecreased by beating and re ning lnk holdout increased by beating and re ning Caliperdecreased by beating and re ning calendaring Opacity decreased by beating and re ning calendaring Porosity decreased by beating and re ning Surface smoothness increased by coating and calendaring hardwoods produce smoother paper Internal strength reduced by coatings Softwoods produce paper with more strength Moist papers have greater strength Surface strengthcan be increased by additives and surface sizing Stiffness can be increased by additives Pick resistancecan be increased by additives lnk absorbency can be increased by additives Gloss increased by calendaring coating and additives Brightnessincreased by coating and llers additive Whitenessincreased by coating and additives Paper Attributes Ligien binder PAPER 0 The primary ingredient in paper is cellulose bers Sources include 0 Trees approx 50 cellulose ber 0 Cotton approx 90 cellulose ber 0 Recycled Fiober 1 Mechanical has 9095 yield but short damaged bers with the lignin not removed SGWStone Ground wood 18405presses logs against a revolving grindstone RMP Re ned Mechanical Pulp 19505 rst the logs must be reduced to chips Then two disks rotating in opposition grind the wood This method produces less damage to the bers and lignin is softened by the heat from friction o TMPThermoMechanical Pulp 1968 Starts with chips that are conditioned by high temperature and pressure Causes even less damage to the bers and produces stronger papers 2 Chemical kraftremoves lignin resins and minerals Produces lower yields at 55 Longer stronger bers less damaging process more permanence Chemical pulping occurs in a digester The digester has high pressure and temperature to force the chemistry into the chips to dissolve the lignin Soda Process 18505Caustic soda or lye NaOH 0 0 High pressure and temperature of the cooking process forces NaOH into the chips It can be dif cult to maintain the correct level of NaOH so some chips are not fully digested shives and some bers are destroyed NaOH breaks down the lignin but too much NaOH breaks down the bers as well 0 Sulfate Process 18805Reduces sodium sulfate to sodium sul de Sodium sul de reacts with water to form more sodium hydroxide the chief cooking agent 0 O O O O NaZS H20 gt NaHS NaOH Result is that NaOH is more easily maintained giving more control to the process for stronger bers Paper made from this process was called quotKraft quotmeaning quotstrongquot Typically produces brown paper with less shives 5055 yield 0 Sul te Process 18801930 Used acidic rather than the alkaline agents NaOH of soda and sul te processes 0 O O O Fibers Acids attacked the bers weaker pulp Need special liner to digerster expensive Doesn t work well with softwoods high resin Stream pollution was an issue Hardwood comes from deciduous trees oak poplar gum beech maple birch chestnut The have short bers 18116 Adds smoothness and consistency to paper Softwood comes from Coniferous needles pine r spruce hemlock and long bers 38 14 Adds Strength to the paper 0 Pulp digester 0 To extract the cellulose from the wood chips the natural binder Iignin must be removed and the cellulose bres laid bare This is carried out in the pulp digester with chemical decomposition methods In the alkaline sulphate method the bers are fed into the digester by means of steam pressure at 180 C The subsequent cooking process using caustic soda sodium carbonate and sodium sulphate is carried out at a temperature of 170 C and under pressures up to 8 bar Automatic operation of the digester requires exact monitoring of the level during lling and also of the pressure during the entire process l I J aquot l Head Box il39o Reel Winder 3935 1 quotll l l 5397 Cid Rll lst 2nd 3rd gfu39Lker 96 Press Press Press quot 39 water Water Flurlnish F olurdrilnier Press Forward 39 Aft Form ilng Section Dryer Dryer Section Section Section 1 Starts with trees amp recycled paper 2 Preprocessed 3Cooked 4 Formed using fourdrinier wire 5 PressedFlattenedSmoothed 6 Using rollers 7 Squeezesout water 8 Wound onto a quotparent rollquot or sheeted Terms to know Basis Weight standard way of specifying the DENSITY of paper Basis Size Ream 500 sheets in a Ream Printability Runablility Watermark Brightness Whiteness Dimensional Stability MWeight Cellulose Fiber CaHper Grain Direction FinishCalendering CoatedUncoated Opacity BOND 17 X 22 TEXT 25 X 38 COVER 20 X 26 INDEX 255 X 305 THEE if paper Eihl Eia ka Ei tting 2 nd 2Eik ver Ei EEi E Gumma In ex L gar H if i H fipt Himaagraph HEWEpri t ff t i ki paqu E st r Tag if T t TiEEuEE H llum hris il writing Size i i hEE 25 22 12 12 25 22 22 25 25 122 l2 l2 l2 12 22 25 12 25 22 22 122 22 25 22 22 122 12 HHHHHHHHEEHHHHHHHEHHHEHH 22 22 22 22 22 2E 22 22 22 22 22 21 22 2E 22 22 22 2E 22 2E 22 2E 22 22 122 122 122 sheetsquot 85 I I quot Wil nlil IEBE u Item1141 17 M r z z Ilia V 1 PHL HEJH Etcrrl p PEPTH V 7 r LEVEL 1 How much does a Ream of paper weigh and why 0 Sheet area of cut sheet X Basic Weight Sheet area of basic size Equivalent weight 0 About 5b QUIZ Basis Weight a standard set for referring to the different papers within a classi cation 0 Basis Weight the weight of 500 sheets of the basic size sheet for that class of paper 0 Four major classes of paper Basic sheet sizes Bond 17quot x 22quot a Bond paper basis size doesn t account for bleeds letterhead etc Text 25quot x 38quot Cover 20quot x 26quot n Grain direction is Index 255quot x 305quot a Tag 24quot x 36 a Bristol 225quot x 285quot Gutenberg born 9281400 printed the bible during 145054 Bookoffset book was designed for letterpress will not print with an offset process offset paper has water repeant sizing agents that will work with offset Run on a 40quot press will print 16 page signature M weight 0 The Mweight is the weight of 1000 sheets of paper any size 0 Paper is a commodity sold by thousandweight 0 Shipping weight is a major expense 0 There is not always 1000 sheets per carton Can have split cartons CaHper THICKNESS How is it measured In mils 005quot 5 mils How is it expressed numerically Verbally Impression setting on an offset press Impression to blanket setting impression between the press and blanket SQUEEZ How to conduct an impression run Quiz Before cutting the NUMBER ONE THING to consider is GRAIN Direction 0 Long or short What is Bond Paper 0 17 X 22 What is Basis Weight 0 500 sheets of a speci c type of paper cut to its BASIC SIZE Review these slides Know the Basic Sizes of Bond text index cover Basis Weight amp MWeight Explain it How to calculate paper weight quantity 0 Know how to read a paper label Pressroom considerations