FREE BOOKS

Author's List




PREV.   NEXT  
|<   76   77   78   79   80   81   82   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100  
101   102   103   104   105   106   107   108   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   >>   >|  
iquor it absorbs mechanically some of it, and this amount may be roughly put down as about its own weight; thus 100 lb. weight of cotton will take up 10 gallons of liquor and carry that quantity out of the bath. To some extent this may be minimised by a previous wetting out of the cotton, which will then have in it as much liquor as it will take up, and so practically no more will be taken up from the dye-bath. Any loss of volume which may thus occur can be remedied by the addition of water. The dye-baths containing in solution, in addition to the dye-stuff, salt, or Glauber's salt, or any other added substance, the cotton in taking up the dye liquor will of course take up some of these in proportion to the volume of liquor absorbed. The amount may range from 4 oz. to 1 lb. per gallon of liquor, and if 100 lb. cotton is being dyed and takes up from 10 to 15 gallons of liquor, it is obvious that it must absorb from 3 to 10 lb. of saline matter, and as the salinity of the dye liquor is of some importance in dyeing direct colours, in making up the bath for the next lot of cotton this must be allowed for and suitable additions made. In order to do this properly it is a good plan to rely upon the Twaddell. The dyer should take the Twaddell of his bath before use and always make up his baths to that strength. This will be found to range from 3 deg. to 12 deg. Tw. Thus, for instance, a dye-bath made from 120 gallons of water with 20 lb. to 25 lb. common salt or Glauber's salt with the dye-stuffs will stand at 4 deg. Tw., one made with 50 lb. common salt or Glauber's salt at 8 deg. Tw., while one which is made with 80 lb. to 100 lb. salt will stand at 12 deg. to 13 deg. Tw. If the dyer always maintains his liquors at one uniform degree Twaddell he can invariably depend upon getting uniform shades from his dye-baths. This uniform strength is attained by adding more salt or more water as the case may require. Of course the continuous working of dye-baths cannot go on for ever; sooner or later the baths become thick and dirty, and then they must be thrown away and a new bath started. (2) DIRECT DYEING FOLLOWED BY FIXATION WITH METALLIC SALTS. It is an acknowledged principle in dyeing that to produce colours fast to washing, soaping and rubbing, there must be produced on the fibre an insoluble coloured substance. Now as the direct dyes do not essentially produce such insoluble bodies when dyed on the cotton, the colou
PREV.   NEXT  
|<   76   77   78   79   80   81   82   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100  
101   102   103   104   105   106   107   108   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   >>   >|  



Top keywords:

liquor

 

cotton

 

Glauber

 

gallons

 

uniform

 

Twaddell

 

common

 

dyeing

 
direct
 

colours


addition

 

substance

 
insoluble
 
strength
 

produce

 

amount

 

volume

 

weight

 

adding

 

stuffs


attained
 

require

 

depend

 
degree
 

continuous

 

liquors

 

maintains

 

invariably

 

shades

 

started


washing

 

soaping

 

rubbing

 
principle
 

acknowledged

 
produced
 

essentially

 
bodies
 
coloured
 

METALLIC


sooner
 

thrown

 
FOLLOWED
 

FIXATION

 

DYEING

 

DIRECT

 

working

 

making

 
remedied
 

practically