November 1, 1920 



THE INDIA RUBBER WORLD 



81 



tard fluur being dusted upon the surface of the plaster after it 

 leaves the calender or spreader. 



For medicated plasters, various drugs, resins and waxes are 

 employed. Thus, one formula for menthol plaster employs rub- 

 ber, gum olibanum, orris root, menthol, Burgundy i)itch, resin. 

 and beeswax. An English formula calls only for rubber, Bur- 

 gundy pitch, and gum olibanum. Another recipe specifies Para 

 rubber, Pontianak, liirdlime (gluten), belladonna and iiaraffine 

 oil. 



POROUS PLASTERS 



The preliminary operation in making plasters is preparing 

 the gums, resins, and waxes. These ingredients are melted by a 

 steam bath and strained for the purpose of removing all dirt 

 and foreign matter. These arc then mixed in a kettle with the 

 medicinal agents required and then incorporated with the sheet 

 rubber on ordinary mixing inills. Each batch is made propor- 

 tionately for 100-gross lots of the regular size porous plasters. 

 The rubber compound is next calendered upon a sheet of fine 

 cambric. This has been previously dried and as it is free from 

 size, the pressure of the rolls sets it firmly into the meshes of 

 the cloth. As the sheet of coated fabric issues from the calender, 

 the coated side is passed under an idler roller onto an octagonal 



fe^/7> 



Blair's Surgical Bandage Machine 



handling reel, as it is necessary to keep the adhesive surface 

 free from contacts. Separate individual maple dowels are used 

 in winding upon the reel. The sheet is left upon the reel until 

 the surface is thoroughly cool. When cool, it is run through a 

 strip cutter and cut into strips usually five inches wide, each 

 strip being wound on a separate spool. The spools, holding 100 

 yards, are passed next to the perforating machines. These ma- 

 chines are specially built and are considered trade secrets. The 

 ordinary plaster is 5 by 7}^ inches, and in this area are some 

 240 one-eighth-inch perforations. The perforating machine cuts 

 this number at once, and not only that, but puts on the light 

 double strips of face cloth, folding their centers, cuts the plaster 

 to size, and passes it along for finishing. 



One machine handles about SO plasters a minute, and in spite 

 of the fact that the product is sticky beyond description, it runs 

 smoothly and steadily day in and day out. Finishing consists in 

 lightly pasting a square of hacking cloth upon the reverse 

 side of the plaster, and packing two dozen in a box for market. 

 NON-POROUS PLASTERS 



It should not be forgotten that non-porous plasters also find 

 a ready market. There is for example the tiny "plasteret." 1 inch 

 by 2 inches for size and sold by the dozen. This is used for 

 burns, scratches, bruises and as a ready means of repair, taking 

 the place of gutta percha tissue. 



The giant of all plasters, however, is the kidney plaster, more 

 than a foot long, six inches wide and curved to fit over the kid- 

 neys. In these the rubber compound is spread upon soft mole- 



skin, died out to shape, backed with a rectangle of cloth, when 

 they are ready for market. The compound consists chiefly of 

 rubber, capsicum and belladonna. 



SURGEON'S ADHESIVE PLASTER 



Perhaps the neatest, if not the most valuable of all, is the 

 surgeon's adhesive plaster. The base is rubber— and good 

 quality rubber. The only adulterant, or rather medicament, is 

 zinc oxide. With the addition of a non-drying oil, this is the 

 whole compound. This tape comes upon the market wound on 

 spools of various sizes so that almost any length or width can 

 be found in the ordinary drug store. In manufacturing, the 

 coated cloth is wound from the calender upon mandrels and cut 

 into short rolls on an automatic lathe. These rolls are then 

 fed into a machine similar to a gromniet setter, which forms a 

 metal spool through and around the roll. It is then put in a 

 tiny carton and is ready for market. 



BANDAGE CUTTING AND WINDING MACHINE 



In this connection a detailed description of Blair's machine for 

 cutting and winding surgical bandages in any width is interest- 

 ing. The sheet of rubber, wound on a roll .-/, passes over the 

 measuring roller B, under a bar C and over the bar D which 

 removes, the wrinkles, and keeps it taut edge- 

 wise. It is then passed over a series of rotary 

 cutters E. and the separate strips are wound on 

 a pair of spindles F and over a loose wire laid 

 alongside the spindles. These spindles are 

 placed end to end and are drawn apart or sep- 

 arated by the sliding pieces G, which are moved 

 by levers // and / pivoted at /. The lower 

 ends of these levers are attached to the right 

 and left-handed screw K, which is operated by 

 the main belt drive through the jaw-clutcb /.. 

 In operating the machine, the spindles F 

 wind up the cut bandages, until a notch M in 

 the wheel N comes against the end of the rod 

 O, causing the driving belt to be shifted to the 

 loose pulley P. This engages the clutch L, 

 causing the screw K to revolve and the levers 

 H and / to separate the spindles F. The rolls 

 of bandage then drop off and remain hanging on the wire. The 

 lever / comes against the stop Q on the bar R, throwing the 

 clutch L out of gear with the wheel 5" and engaging it with a 

 ■wheel T which revolves the screw K in the opposite direction, 

 bringing together the spindles F. Another stop U on the bar R 

 causes the clutch L to be moved midway between and out of gear 

 with the wheels S and T. The finished bandages are cut oflf, 

 another loose wire is laid against the free hanging ends of the 

 cloth, which are placed on the spindles, and the machine is again 

 set in motion. 



CORN PLASTERS 



In speaking of adhesive plasters it would not do to ignore those 

 that bring comfort to the pedal extremities. They are of ancient 

 origin and have attracted the inventive genius of such notables as 

 Sir Humphry Davy and Sir Astley Cooper. To be sure, their 

 formulas, salt of sorrel and potash or yellow wax and verdigris, 

 are no longer used, but they paved the way for the present sani- 

 tary effective rubber corn plaster. 



The compounds used vary but little. A well known one 

 follows : 



Per Cent 



Extract of cannabis indica 10 



Resin compound 70 



Salicylic acid 20 



The last named is the non-drying rubber base, practically the 

 same that is used in porous plasters. The compounding is done 

 as in other plaster work and so is the calendering and general 



