Leather trades chemistry; a practical manual on the analysis of materials and finished products by Trotman S. R. (Samuel Russell)

Author:Trotman, S. R. (Samuel Russell)
Language: eng
Format: epub
Tags: Leather, Chemistry, Technical
Publisher: London, C. Griffin & Company, limited
Published: 1908-03-25T05:00:00+00:00

100*0 189-4

1908

147*2

106*8

126*9

182*2 100*0 126*4

161-8

122-7

146*8

' 96*1 I 178*1

1010

94*2

121-8

;i261 ' 94*9 , 117*8

' 144*3

116-8

139*8

8*9 16*3

89-8

63-0

4*6

7*1 6*1 8-6

7*6

7*4

7*0

Washed Powder.

Percentages of Dry Non-Tanning

Substance estimated as Tannin.

92*0 186*2

88-3

90*1

1160

120*0 891 108*2

118*4

100-7

122*4

® 5

80

64-2-

102-6' 67*1 j

•• i 10*9'

12*2 10*9 18-2

83*4

22-0

24*4

|1

89-4

6*4

- 4*0

97*8 90-1

86-7 96*4 891» 96*9

il II

49*6 48-3

-6*2 -41

I

-7*0 -4*0

57*0

78*0' 88*8

106*6 ' 87*0

84*6 72*3

61*4 66*6

44*9 61*1

60*7 71-2

Pae8sler*8 Method. —Paessler's method is typical of those employing lightly chromed hide powder, and, in addition, he uses it dry and in connection with the filter bell. The chromed powder merely reduces the swelling in the bell, and the tannin absorption is more complete and hence the non-tannin figures more correct; further, according to Paessler and Appelius (J.S.CLy 1907, 213), lightly chromed hide powder gives better results in the filter bell than either ordinary powder or heavily chromed dry powder, while it also absorbs neither grape sugar, cane sugar, nor dextrin, and much less gallic acid than heavily chromed powder. The authors gave the following methods for the manufacture of lightly chromed powder to be used in the filter bell:—

1. Five hundred grms. of unacidified hide powder are churned with 10 litres of water, and 16 grms. of chrome alum dissolved in 500 c.c. of water are added at intervals, the chroming extending over 3-4 days. The mass is squeezed, and well washed with distilled water until free from sulphate, when it is dried and ground.

2. To one kilo, of hide, use 10 grms. of chrome alum and 2^3 litres of water, the chrome alum solution being added at intervals. After chroming, the hide is twice drummed with sodium silicate solution (10

grms. of sodium silicate and 2*5 litres of water per kilo, of hide) to neutralise acidity, drummed again with fresh water, and then stretched in a frame to dry. After drying, the hide is ground.

Weiss (De)' Gerber, xxii. 260-261, 275-278, 1905; J.S.C.L, 1906, 1129) proposed a maceration method which has been for some time in use at the Vienna Research Institution. The powder is prepared by digesting 1000 grms. of cellulose-free ordinary bide powder with a solution of basic chromic sulphate made by neutralising 150 grms. of chromic alum with 24 grms. of sodium carbonate. After chroming, the powder is washed with water till free from sulphuric acid, and then the excess of water is squeezed out and the residual powder dried and ground. For detannitiing, 8 to 10 grms. of the dry powder are moistened with 30 cc. of water and allowed to stand for 1 hour. One hundred and twenty cc. of tannin solution are then added, the mixture being thoroughly shaken and allowed to stand over-night in a stoppered cylinder or bottle. Next morning the mixture is 61tered and 100 cc. evaporated for the determination of non-tannins, a correction for the quantity of water added being made by multiplying the weight of residue by -. With the exception of some highly

coloured tannin liquors, such as mangrove, 10 grms. of powder will usually be sufficient; if not, the solutions are diluted with an equal volume of water before use.

Wood and

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.