|
| Class | 1. | 2. | 3. | 4. | 5. | 6. |
|
| Mean tearing length in metres | 6,000 | 5,000 | 4,000 | 3,000 | 2,000 | 1,000 |
| Elasticity per cent. | 4 | 3·5 | 3 | 2·5 | 2 | 1·5 |
| Resistance to folding (Schoppers' method, number of foldings) | 190 | 190 | 80 | 40 | 20 | 3 |
|
The tests for tearing length, resistance to folding, elasticity, etc., are made in air showing relative humidity of 65 per cent. The calculations for tearing length are made on strips of paper dried at 100° C.
(C) Classification according to Use.
|
| Class. | Uses. | Fibre. Class. | Strength. Class. | Size of Sheets. Cm. | Weight of |
|
| 1,000 Sheets. Kg. | 1 Sq. Metre. Grms. |
|
| 1 | Writing papers for important documents | 1 | 1 | 33 × 42 | 15 | — |
| Paper for State documents | 1 | 1 | 26·5 × 42 | 12 | — |
| 2 | Paper for registers, account books, and ledgers— | | | | | |
| (a) First quality | 1 | 2 | 33 × 42 | 14 | — |
| (b) Second quality | 1 | 3 | 33 × 42 | 13 | — |
| 3 | Documents intended to be preserved longer than ten years— | | | | | |
| (a) Foolscap paper | 2 | 3 | 33 × 42 | 13 | — |
| Letter paper (quarto size) | 2 | 3 | 26·5 × 42 | 10·4 | — |
| Letter paper (octavo size) | 2 | 3 | 26·5 × 21 | 5·2 | — |
| Duplicating paper | 2 | 3 | 33 × 42 | 7 | — |
| (b) Official writing paper | 2 | 4 | 33 × 42 | 13 | — |
| 4 | Paper for documents of lesser importance— | | | | | |
| (a) Foolscap paper | 3 | — | 33 × 42 | 12 | — |
| Letter paper (quarto size) | 3 | — | 26·5 × 42 | 9·6 | — |
| Letter paper (octavo size) | 3 | — | 26·5 × 21 | 4·8 | — |
| (b) Official writing paper | 3 | 4 | 33 × 42 | 12 | — |
| 5 | Envelopes and wrappers— | | | | | |
| (a) First quality | — | 3 | — | — | — |
| (b) Second quality | — | 5 | — | — | — |
| 6 | Writing paper of medium quality | — | 5-6 | — | — | — |
| 7 | Covers for documents— | | | | | |
| (a) That required for frequent use | 1 | Tearing | 36 × 47 | 81·2 | 480 |
| | | length 2,500 Elasticity 3·5% | | | |
| (b) For other purposes | 3 | Tearing | 36 × 47 | 42·3 | 250 |
| | | length 2,500 Elasticity 2·5% | | | |
| 8 | Printing paper— | | | | | |
| (a) For important printed matter | 1 | 4 | — | — | — |
| (b) For less important printed matter | 3 | 4 | — | — | — |
| (c) For common use | — | 5-6 | — | — | — |
|
ANALYSIS, TECHNOLOGY, ETC.
Abel, Dr. E. Hypochlorite und electrische Bleiche. Halle, 1905.
Arabol Manufacturing Co.—Theory and Practice of the Sizing of Paper. New York, 8o, 1895.