482 



THE INDIA RUBBER WORLD 



Developments In Rubberized Unwoven Fabrics. 



/)'y Koland B. Rcsfcss. 



WO\'F.N FABRICS and fibrous materials enter very largely 

 into rubber manufacture, for strengthening or "tilling" rub- 

 ber goods. Fibers have been used as a filler by mixing 

 with rubber and sheeting out of the compound or forming 

 it in molds. Where it is desired that the fibers be of the 

 form to give considerable added strength to the rubber products 

 woven cloth is usually employed. Unwoven fabrics give as great 



[► - From Cotton Batting to Artificial Le.-vther. 



or greater strength than woven goods, and may be used in 

 rubber manufacture more cheaply than woven goods, and are 

 therefore, not only of interest as offering possibilities in improve- 

 ing the product but in cost reduction as well. 



The writer experimented to produce an unwoven fabric to 

 be used in making automobile tires. His first attempts were 

 along lines disclosed as far back as 1867 in a patent issued to 

 Charles Saflfray, M. D., who used a cotton batting which he 

 saturated with a binding agent, using wire mesh to hold the 

 fiber sheet when dipped in a thin liquid solution, after which 

 it was pressed to take out the excess solution, and dried and 

 sheeted, to be used as a leather substitute. Investigation of the pat- 

 ent records did not disclose a practical method of manufacture, 

 and the writer started out to devise and develop such methods. 



In his early experiments he succeeded in making a 

 strong sheet resembling split leather, which was capable of being 

 coated and embossed to simulate leather, but this sheet was no 

 more successful than the experiments of a number of others, 

 and it was decided that such fabric would not be suitable for 

 automobile tires because it would stretch like leather, and the 

 tire probably would not hold its shape. 



Experiments with cords and threads were then begun and 

 later the fiber sheet was combined with the cords and threads. 

 During the course of these experiments results were produced 

 which appeared adaptable to many uses in the rubber trade, but 

 the conditions resulting from the war presented a serious handi- 

 cap due to the difficulty in gaining assistance from those who 

 were engaged in government work. After two years of con- 



weight desired. The fiber then passes to a saturating machine 

 where a heavy rubber solution is pressed into the fibers to satur- 

 ate or coat each individual fiber, after which it goes to a dryer 

 where the solvent is evaporated, and then it is passed between 

 heavy pressure rolls and pressed into a firm sheet resembling 

 split leather, the entire process occupying not over twenty 

 minutes — from cotton to "leather." 



This leather is then ready to be coated with rubber surface 

 dressing after which it may be embossed to design and vulcan- 

 ized; or, if the leather dressing is to be of cellulose or similar 

 dressing, the sheet is vulcanized and then coated, after which 

 it may be embossed to any design required. The leather may be 

 made any weight or width and any length in which the rolls may 

 be handled. Its strength can be varied as may be required, 

 and some samples produced have tested up to 6,250 pounds to the 

 square inch, giving nearly double the strength of standard belt 

 leather. For greater strength there are other processes, in- 

 cluding strings or cords placed in the direction of greatest 

 strain, which will produce belting having a tensile strength up 

 to 10,000 pounds. 



The peculiarity of this leather when examined closely is that 

 it does not look like rubber at all, but resembles genuine 

 leather. It is difficult to decide that rubber actually enters into 

 its composition. The stronger sheet has the appearance of raw- 



RuBBER Tapes or Belting, of Cotton Fiber. 



stant work, the writer is now able to present a brief outline of 

 what he has accompUshed and covered by his patents and appli- 

 cations for patents. 



The production of leather substitute, for instance, has been 

 worked out to the point that the cotton from the bale, or cotton 

 linters, old rags, old jute bags, etc., are put in a picking machine 

 that picks apart the fibers, which are then fed to a carding or 

 garnett machine and formed into fiber batting of any width or 



Rubber Shoe Laces Made from Cotton Fiber. 



hide and the other sheets look like split leather. By use of a 

 sizing on the surface of the cotton sheets before saturation-, a 

 product almost identical with the hair side of genuine leather 

 is produced. It may be finished with ordinary shoe polish or 

 dressing and resembles and has the feel of kid leather. Any 

 kind of dressing that is used in finishing leather or artificial 

 leather may be used. It may be finished by hand as hides 

 are finished, and give the same rich appearance, or it may be 

 finished by machinery as artificial leather is produced. The 

 samples finished in black or colored patent leather feel and 

 look like the genuine article. There seems to be a perfect 

 affinity, in this process, between the cotton and the rubber and 

 between the rubber and the cellulose or oil dressings. 



The field for use of this leather alone seems very great, but 

 the leather in sheet form seems only the beginning of its pos- 

 sibilities. After the sheet rolls are prepared and before they 

 are vulcanized, the material may be cut to forms and molded 

 or laminated and thereafter vulcanized to retain its form. This 

 quality opens a wide field for development in the manufacture 

 of power and transmission belts which may be made with or 

 without the thread or cord reinforcement ; also shoe counters 

 and slippers vulcanized in one piece may be produced and such 

 slippers may be sterilized, subjected to any reasonable heat or 

 boiled without injury. Hospital blankets may be made without 

 the cold, clammy feel of rubber blankets and yet having their 

 waterproof qualities. Also boxes, cases, suitcases, bags and 

 hundreds of small formed articles for which leather has been 

 heretofore used exclusively, may be produced rapidly and 

 cheaply. 



