Chemistry of Papermaking — About 3000 chemicals used in papermaking!

HISTORY

Paper was first invented in ancient China by Cai Lun. Chinese made the first paper from fibers of plants such as hemp. The plant fibres were soaked and beaten into sludge. The sludge was strained through a cloth sieve attached to a frame that also served as a drying platform for the resulting paper. Papermaking was introduced to Korea and Vietnam during the 3rd century and to the West around the 8th century. The first paper mill in Europe was built in 1009.

ROLE OF CHEMICALS

There are about 3000 or so different types of chemicals which can be used in papermaking, in practice only about 200 individual chemicals are typically used, each satisfying a specific need. Some of the important chemicals used are -

1) Caustic soda, sodium sulfide for the Kraft process, the process of conversion of wood into wood pulp consisting of almost pure cellulose fibre.

2) Sulfurous acid for the Sulfite process

3) Caustic soda, Anthraquinone for the Soda pulping

4) Caustic soda is added to increase the pH in the pulping process of fibers. The higher pH of the paper fiber solution causes the fibers to smoothen and swell, which is important for the grinding process of the fibers.

5) Sodium dithionite, chlorine dioxide, hydrogen peroxide, ozone for bleaching of wood pulp

6) Bleaching additives: sodium silicate

7) sequestering agents: EDTA, DTPA

APPLICATIONS

Paper finds a wide range of uses –

1. One of the major use of paper is for books, charts, cards, report card etc.

2. Paper is used in making writing pads, envelopes, newspapers, magazines, greeting cards, calendars, diaries, telephone directories, labels, business and passports.

3. Paper is used in making domestic products such as tissues, paper plates, paper cups, toilet paper, kitchen towels, table napkins, wallpaper and lampshades.

4. Paper finds use in special insulating boards, electrolytic condenser paper, wrapping and identification for electrical cables, printed circuits, and battery separators.

5. It is also used for making menu cards, paper hats, crackers, wrapping paper, playing cards, board games, kites, model aircraft, and race cards.

6. Paper is used in making filters for water, air, tea bags, medicine, beer, oil, and mechanical uses.

7. Impregnated Papers are used polishing, waxing, and cleaning.

8. It finds use in medical field for wrapping to keep instruments and equipment sterile, bandages, first aid bands, clothing for nurses, face masks, surgeons’ caps, disposable bed pans, sheets, and pillowcases.

9. Another important use of papers are for bank notes, insurance forms, cheque books, stamps, cash bags and security papers that contain special markings which are only visible when subjected to ultra-violet light.

PAPER MANUFACTURUING COMPANIES

1) International Paper, Memphis, TN, US

2) Stora Enso , Helsinki, Finland

3) Oji Paper, Tokyo, Japan

4) Nippon Paper, Tokyo, Japan

5) Cellulosa Aktiebolaget (SCA), Stockholm, Sweden

6) UPM , Helsinki, Finland

7) Kimberly Clark, Dallas, Texas, US

8) Smurfit Kappa Group, Dublin, Ireland

9) Mondi, Addlestone, UK; Johannesburg, South Africa

INTERESTING FACTS ABOUT PAPER

  • Paper was invented by the Chinese around 105 A.D. and was kept a secret for many years.
  • Every tonne of paper that is recovered saves 3.3 cubic yards of landfill space.
  • It takes 7 days for a recycled newspaper to come back as a newspaper again.
  • We use kraft paper every day when we ask supermarkets to pack our groceries in brown paper bags.
  • All of the newspaper made in the UK is now made from 100 per cent recycled paper.
  • Much of our toilet paper is made from recycled paper.
  • Corrugated cardboard packaging consists nearly of 100 per cent recycled material.
  • Paper bags were first measured by how many pounds of sugar they held.
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