Chemistry:Printing and writing paper

From HandWiki

Printing and writing papers are paper grades used for newspapers, magazines, catalogs, books, notebooks, commercial printing, business forms, stationeries, copying and digital printing. About 1/3 of the total pulp and paper marked (in 2000) is printing and writing papers.[1] The pulp or fibers used in printing and writing papers are extracted from wood using a chemical or mechanical process.

Paper standards

The ISO 216:2007 is the current international standard for paper sizes, including writing papers and some types of printing papers. This standard describes the paper sizes under what the ISO calls the A, B, and C series formats.[2]

Not all countries follow ISO 216. North America, for instance, uses certain terms to describe paper sizes, such as Letter, Legal, Junior Legal, and Ledger or Tabloid.[3]

US Paper Sizes
Size Width x Height (mm) Width x Height (in) Aspect Ratio
Half Letter 140 x 216 mm 5.5 x 8.5 in 1:1.5455
Letter 216 x 279 mm 8.5 x 11.0 in 1:1.2941
Legal 216 x 356 mm 8.5 x 14.0 in 1:1.6471
Junior Legal 127 x 203 mm 5.0 x 8.0 in 1:1.6000
Ledger/Tabloid 279 x 432 mm 11.0 x 17.0 in 1:1.5455

Most types of printing papers also do not follow ISO standards but have features that conform with leading industry standards.[4] These include, among others, ink adhesion, light sensitivity, waterproofing, compatibility with thermal or PSA overlaminate, and glossy or matte finish.[4]

Additionally, the American National Standards Institute or ANSI also defined a series of paper sizes, with size A being the smallest and E the largest. These paper sizes have aspect ratios 1:1.2941 and 1:1.5455.[3]

ANSI Standard Paper Sizes
ANSI Paper Size Width x Height (mm) Width x Height (in) Aspect Ratio Closest ISO Size
A 216 x 279 mm 8.5 x 11.0 in 1:1.2941 A4
B 279 x 432 mm 11.0 x 17.0 in 1:1.5455 A3
C 432 x 559 mm 17.0 x 22.0 in 1:1.2941 A2
D 559 x 864 mm 22.0 x 34.0 in 1:1.5455 A1
E 864 x 1118 mm 34.0 x 44.0 in 1:1.2941 A0

Vietnam

Specifications MD/CD Unit Level A Level B Method
Substance gsm 80-120 60-80 TCVN 1270:2000
Durable ≥ mN.m2/g TCVN 3229:2000
MD 5.7 4.1
CD
Tearing
strength ≥
m TCVN 1862:2000
MD 3800 3200
CD 2200 1800
Water
absortiveness
Cobb 60
g/m2 23 23 TCVN 6726:2000
Brightness ISO ≥ % 78 70 TCVN 1865:2000
Opacity % 85 85 TCVN 6728:2000
Roughness
Bendtsen ≥
ml/
minute
280 400 TCVN 3226:2001
Ash content ≥ % 3 3 TCVN 1864:2001
Moisture
content
% 7±1 7±1 TCVN 1867:2001

Types

  • Fine paper
  • Machine finished coated paper
  • Newsprint

History

The history of paper is often attributed to the Han dynasty (25-220 AD) when Cai Lun, a Chinese court official and inventor, made paper sheets using the “bark of trees, remnants of hemp, rags of cloth, and fishing nets.”[5] Cai Lun's method of papermaking received praise during his time for offering a more convenient alternative to writing on silk or bamboo tablets, which were the traditional materials in ancient Chinese writing.[6]

On the other hand, archeological evidence supports that the ancient Chinese military had used paper over a hundred years before Cai Lun's contribution[6] and that maps from early 2nd century BCE were also made with paper.[5] With this, it appears that what Cai Lun accomplished is not an invention but an improvement in the papermaking process. Today, even with the presence of modern tools and machines for papermaking, most processes still involve the traditional steps that Cai Lun employed, namely the process of soaking felted fiber sheets in water, draining the water, and then drying the fiber into thin sheets.[7]

In 1690, the very first paper mill in America was established by William Rittenhouse.[8] The mill became the largest manufacturer of paper in America for over a hundred years until other paper mills sprang up, including the paper mill by William Bradford which supplied paper to the New York Gazette.[9]

References