Kraft Paper and its Uses 



By W. R. Brown 



THE many new and useful articles which are being 

 manufactured out of paper, and more particularly 

 out of Kraft paper, are of interest on account of 

 their unusual character, and because they represent reduc- 

 tion in the cost of living and a close utilization of forest 

 product, with its attendant beneficial effect on forestry. 

 As is usual in matters of close utilization, foreign coun- 

 tries have been the pioneers in the use of wood fiber, and 

 many of the products which are the subjects of illustration 

 are of Scandinavian manufacture. Their manufacture in 

 this country will no doubt only be a matter of a short 

 time, and open a wide tield for profit. 



The process of manufacturing sulphate pulp, from 

 which Kraft paper is made, originated some twenty years 

 ago in Sweden, and for some ten years was carried on in 

 Sweden, Norway and Finland before being introduced 

 into this country. The first mill for manufacturing svd- 

 phate pulp on this side of the Atlantic was established by 

 the Brompton Pulp and Paper Company, at East Angus, 

 Quebec, and they still continue one of the large pro- 

 ducers, being exceeded only by the Wyagamac Pulp and 

 Paper Company, at Three Rivers, Quebec, and the 

 Brown Corporation, at La Tuque, Quebec. 



Briefly, the process is what is known as the soda ash 

 process to distinguish it from the suljihite process, the 

 main points of difference being that the principal chemical 

 used in the sulphate process is sodium sulphate, com- 

 monly called salt cake, which is mixed with chloride of 

 lime to form caustic soda, and this, when reduced by heat, 

 forms sodium sulphide carbonate, commonly known as 

 black ash. 



Sulphate pulp is sold to paper maiuifacturers through- 

 out Canada and the United States, and there are thirty 

 or more mills using this pulp which produce a little over 

 a thousand tons of Kraft paper daily. 



The distinguishing characteristic of Kraft is its ex- 

 treme strength and resistance to wear by folding, due to 

 the gentle action of the chemicals, which disintegrate the 

 cellulose from the lignin and preserve the long fiber of 

 the wood. It is of the brown color which is so often seen 

 in wrappings for parcels or magazines. The tensile 

 strength of this paper in comparison with other manilki 

 wrappers of equal weight and thickness is from one- 

 quarter to one-half greater. On account of the marked 

 superiority of Kraft, many imitations ha\'e been put upon 

 the market, but a return to the use of the original has 

 almost alwavs followed. While the price of Kraft is 

 somewhat higher for wrappers per pound, the customer 

 secures nearly half again additional area and a much 

 stronger and more serviceable paper. 



Large quantities of Kraft paper are used in the depart- 

 ment stores, and particularly by the large mail-order 



l.so 



houses in the West who ship by parcel post. It is par- 

 ticularly suitable for envelopes, especially such as are 

 manufactured for heavy documents and money, in place 

 of leather-board containers. Strips of Kraft paper are 

 used in binding the corners of cardboard boxes, particu- 

 larly shoe boxes. Strips of gummed Kraft paper are 

 used in the same manner as twine about boxes and pack- 

 ages, and are much stronger and do not slip off'. Even 

 coal is now being delivered in bags made of Kraft in 

 place of canvas bags which had to be emptied and re- 

 turned, the paper bags being merely burned up with the 

 coal. With a light backing of cloth fiber and a filler 

 against dampness, Kraft paper, called "Watershed," is 

 used for covering automobile tires for shipment in place 

 of burlap. "Watershed" paper is also used for the oversea 

 shipment of dry goods and groceries. Kraft cardboard 

 is used in the manufacture of dress suit cases. Embossed 

 Kraft paper is used for wallpaper, book covers, and for 

 covering fancy boxes. Very good imitation leather is 

 made from Kraft. Stripped into narrow rolls one-eighth 

 of an inch wide, it is run through a machine which gums 

 one side. The gummed side is spread with a fine lint of 

 cotton or linen. These strips are then run in a spinning 

 machine and twisted into threads, from which the cotton 

 and linen fibers protrude as a thin fuzz. This thread is 

 afterward woven into various fabrics, as imitation burlap 

 for wallpaper, cloth for upholstering furniture, grain 

 bags, tailors' lining for suits, imitation cotton and linen 

 towels, webbing, straps for surcingles, bedding, etc. By 

 the introduction of colored thread and stamping in colors, 

 pleasing designs are worked into the fabrics. Small 

 twine made of twisted Kraft paper is used for tying up 

 bundles ; is woven into coarse mattings, and furnishes 

 the warp for cheap rugs and carpets. Twisted into manv 

 strands, it is woven into all sizes of rope, particularly 

 laundry and window rope and binder twine for harvest- 

 ing machines. To add strength, it is sometimes spun on 

 a hemp core. One piece of rope of Kraft paper has a 

 breaking strength of 28 pounds and runs 383 feet to the 

 pound; another has a breaking strength of 24 pounds 

 and runs TTiO feet to the pound; a third has a hemp cen- 

 ter, a breaking strength of 43 pounds and runs 642 feet 

 to the pound. Kraft paper is also now being used as in- 

 sulation in the wrapping of overhead and underground 

 copper cables. 



By a new patented process, the Berlin Mills Company 

 is now producing paper pipe wound over cores of various 

 diameters and made in \arious thicknesses, which is 

 thoroughly permeated with a tar compound, forming a 

 strong, compact pipe capable of taking a thread and 

 lighter and less expensive and more durable than iron 

 ])i|)e. This is used for various purposes, such as under- 



