Name/Title
RecipeEntry/Object ID
2018.20.06Scope and Content
Four paper pages [a, b, c, d] of a set of instructions for making dyes. The paper used to make the pages is machine woven and contains a watermark that reads "ROCKLAND BOND MADE IN CANADA". The media on the pages is blue ink [possibly faded black] which covers approximately 40% of the pages in the form of paragraphs of typewritten text.
Transcription of artifact is as follows:
Combined Keir Boil and Bleach
Boil out first for 2 hours with NaOH then follow with ½ Volume Peroxide plus 6-7 lbs. Silicate per 100 gallons.
Some mills combine above into ONE boil, using
7 lbs. Silicate
1 lb. Caustie
6 ozs. Gardinel
6 lbs. 100 Vol. Peroxide
Per 100 gallons.
Temperature must be 180 or over to get bleaching in a reasonable time - 6 hours is considered standard.
For colored work such as towels, do not go over 180F to protect vat colored threads. Pack keir with heavy shades at top and light shades at bottom, since weight of goods pressing on load at bottom causes more severe action of boil out. In the case of combined bleach and boil-off there is no need to add Ludigol, as Peroxide does the oxidizing.
Pieces are done in a keir by this process; yarns may be done in chain form in keir, or in packages on Franklin.
Combined boil and bleach takes out less from the goods than a kier boil followed by Chlorine bleach and gives a softer feel.
Precautions and control of Peroxide Bleaching.
Theory of Peroxide Bleaching is to secure a controlled decomposition of the Peroxide, adjusted as to speed in accordance with the requirements of the machine in use.
For example, a lot of yarn in an open tub would call for a reasonably quick bleaching action, so as to save time and labor, since there is ready and instant access of solutions to
[the following is written on page b]
All parts of the yearn. By contrast, a lot of, say, towelling in a kier would need to be bleached at a much slower rate, since it takes at least 1 ½ hours to secure even penetration of the Peroxide liquors throughout the mass of fabric in the machine. Hence, a quick-acting solution would result in uneven results, as it would be more or less exhausted before it reached some parts of the load of goods.
The so-called Stabilizers such as Silicate Phosphates, etc., are not really Stabilizers at all, as they actually promote decomposition of the Peroxide, which is acid when received and which is stable only when acid. These compounds should structly be called “Regulators”.
Factors governing rate of Decomposition.
Temperature - Rising temperature speeds decomposition.
pH - Higher the pH, more rapid the decomposition, but all Alkalis do not give same rate of breakdown of Peroxide. Silicate of Soda adjusted to Na20.55103 gives slowest rate of reaction. TriSodium Phosphate comes next, then Ammonia and Caustic Soda. Sodium Pyrophosphate is good at low temperatures, but at or near the boil, it is rapidly converted into normal phosphates and rate of decomposition is, thereby, speeded up. In practice T.S.P. gives softer results, and if the amount used is not more than the Silicate in the formula, the speed of reaction is not appreciably increased. pH of 9.8 to 11 is range for practical work.
The cotton itself has a pronounced stabilizing effect on Peroxide solutions.
Water - Hard water gives slightly more stable sol-
[the following is written on page c]
Utions than soft water. Iron in the water to be avoided-catalytic action speeds up decomposition tremendously, so that Oxygen is liberated far more rapidly than it can be taken up by the cotton for bleaching purposes and hence is wasted. Also, if iron spots are present on the goods the reaction, at that point, is so very vigorous that tendrils will occur. The same remarks apply to Copper.
Machine - Iron O.H. when coated with Lime, etc. and Silicate Monel Metal speeds up the decomposition to some extent, but not enough to cause trouble. Stainless steel, Cement and Wood O.K. but wood perishes badly in time, and is also inclined to give brown stains when new.
Sodium Peroxide sometimes used for cheapness, though it is dangerous stuff to handle. Cotton is boiled out with at solution of about 3 lbs. Of Sodium Peroxide to 100 gallons of water. No additional alkalinity is needed.
Chlorine Bleaching of Cotton.
Cheap, easy to handle, can be arranged to run as continuous process, no steam costs.
Use Sodium or Calcium Hypochlorite, with free Chlorine content of 2-7 parts per 1000, which is ½ - 2tw.
Sodium Hypochlorite can be bought in concentrated liquid for with a Chlorine content of 100 parts per 1000. In the case of the Calcium Compound, new products, such as, H.T.H., Maxoclor, have a much higher active ingredient content than the old Bleaching Powder, and are convenient for small lots at intervals.
For continuous large scale operations, the best way is to buy Chlorine gas in cylinders and pass into NaOH solution A
[the following is written on page d]
Solution of Caustic at about 6 lbs. Per 10 gallons is prepared in a barrel, which is set on a scale and then Cl gas is bubbled in until the required increase in weight is obtained. Theoretically, 100 lbs. Cl will convert 112.5 lbs. NaOH, but usually use a little excess of NaOH. The bleaching solution as finally prepared, should have a PH of 9-11 for maximum bleaching effect with minimum damage to cotton. Nearer to neutral point, more damage. Bleaching always cold.
Explain that Cl does not do bleaching, but the Oxygen set free.
In practice goods passed through Bleaching solution and then exposed to air. (precautions against drying out) for 1 hour or so. CO2 in air has definite effect in promoting bleaching by liberation free HC10. Goods well wasked, sour with HCl to liberate HClo which is easier to wash out. Sometimes use antichlor, such as, Bisulphate or Thiosulphate. In continuous operations where goods are ropewashed, some bubble SO2 gas into water is machine.
Same precautions against Iron and Copper as in Peroxide work.
When bleaching coloured goods with Vat stripes, cut pH to 9. This way bleaching is slower, but not so hard on colours.Cataloged By
Plewes, ColeLexicon
Nomenclature 4.0
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RecipeNomenclature Sub-Class
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Documentary ObjectsNomenclature Category
Category 08: Communication ObjectsLocation
Location
Container
Archive Box 3Shelf
1Cabinet
Archive CupboardRoom
Collections RoomBuilding
M.V.T.M.Category
PermanentDate
November 7, 2023General Notes
Note
Status: OK
Status By: MacMillan, Lindsay
Status Date: 2020-11-26Created By
admin@catalogit.appCreate Date
June 15, 2019Updated By
admin@catalogit.appUpdate Date
November 11, 2023
