US2433370A - Method of scouring cellulosic materials - Google Patents

Description

Patented Dec. 30, 1947 METHOD OF SCOURING CELLULOSIC MATERIALS Hans 0. Kauffmann, Eggertsville, and Robert L. McEwen, Edward S. Shanley, and John R.

Hopkins, Buffalo, N. Y., assignors to Buffalo Electro-Chemical Company, Inc., Buffalo, N. Y.

No Drawing. Application April 24, 1940, Serial No. 331,438

7 Claims.

The present invention relates to a method of treating goods made of fibers of vegetable origin whereby the goods are prepared so that they may be more readily acted upon. by conventional bleaching agents. More particularly, the present invention relates to a preliminary treatment prior to bleaching which includes the padding and steeping of gray goods with an aqueous solution of an alkali.

Heretofore, prior to the treatment of goods with bleaching agents, or solutions containing such agents, the gray goods were preliminarily treated with hot circulating alkali solutions in order to remove certain waxy and resinous constituents of the cellulosic fiber that rendered it non-absorbent and which contribute to the natural dark color. In general, the fibers were scoured by treating the same in a hot circulating solution of caustic soda or the like, or equivalent alkali. The

goods were heated for a considerable period of time in this hot circulating alkali until substantially all of the waxy fiber coating had been eliminated and the fiber rendered soft and absorbent. The boiling was performed for considerable periods of time, say, from 8 to 20 hours either in open kiers or in closed kiers under pressure.

' Many disadvantages accompany these so-called caustic boils. Forinstance, the goods after treatment are often uneven in physical and chemical character, such as absorbency, tensile strength, softness, and the like. Unless great care be taken in packing the goods in the kier, channeling of the circulating solution is likely to occur whereby greater contact with the solution is to be had at certain points than at others. Furthermore, as the waxy material is eliminated, more and more scum collects in the solution, is carried by the solution and may at times deposit on the goods with the production of spots. Furthermore, the goods are quite likely to be stained with rust and other marks from the kier, particularly if the boil is performed under pressure.

It is an object of the present invention to soften and loosen and to substantially remove a considerable portion of the waxy material surround ing the cotton fiber, and also to soften, loosen and substantially absorb any motes that may be present in the goods being treated.

It is a further object of the invention to provide a treating method preliminary to bleaching treatments for cellulosic fiber wherein considerable saving is effected in steam consumption in the preliminary treatment of the gray goods.

In accordance with the present invention, gray goods are padded with an aqueous solution of an alkali so that the goods contain from 50 to 200% of the solution, based on the weight of the dry goods. The goods so padded are then permitted to stand in this soaked, padded or damp condition until the waxy foreign matters of the fibers and any motes are softened and substantially removed or are changed to a condition where they are readily removable and then heated under conditions where substantial evaporation of moisture is prevented and the goods thus maintained in the damp condition. In general, the steeping of the gray goods padded with the alkali will require from 4 to 20 hours, more or less, and will depend to a large extent upon the type of goods being treated, whether heavy goods or light goods, the quantity of alkali in the padding solution and the temperature of the steep.

After the waxy material in the cellulosic fibers has been softened and loosened and changed to a form where it is readily removable, the goods are heated, as, for instance, by steaming for a short period of time, say from 30 seconds to 30 minutes. ishes the alkali treatment and places the goods in excellent condition for bleaching.

The steep with the alkali will normally be effected at room temperature or temperatures somewhat removed from room temperature. For purposes of impregnating the goods with the alkali solution any conventional procedure may be employed. In general the preferred procedure will be to run the goods through the alkali solution, the temperature of which may be room temperature 0r temperatures somewhat above room temperature. After uniformly wetting the goods in this manner, excess solution is squeezed out and the so padded goods then laid down in this damp condition (containing from 50% to 200% of the solution, based on weight of goods) and permitted to steep. This steeping is continued for from 4 to 20 hours or until the waxy matters are readily removable or the motes softened and loosened, after which time the goods are steamed and washed with water.

Although caustic alkali is preferred in making up the alkali solution, other generally used alkali may be substituted or added therefor or thereto, for instance, sodium carbonate, trisodium phosphate, sodium silicate, lime, and'the like. The amount of alkali in the padding solution should be relatively high. It may be mentioned that caustic soda is the alkali preferred and in general the alkali would be from about 15 to 60 grams per liter NaOH, it being understood that for heavy ducks and drills larger quantities of This steaming softens the goods, finalkali will be required to produce the desired effect than are necessary on lighter types of goods. In general, 25 to 40 grams NaOH per liter will be found a satisfactory concentration for most cotton goods; sodium silicate may be mixed advantageously with the caustic soda,

After the lay down and steep, the goods are heated rapidly under conditions where excessive evaporation of water from the goods is prevented. In general, this heating is effected by steaming the goods, that is to say, the goods are placed in" an atmosphere of steam or, where the goods are in a heavy condition, steam is passed directlythrough the goods in order to heat al l p qntiens thereof evenly to obtain the efi eet on the wax and motes desired. In general, this steaming is carried out for relatively short periods off-time, although it will be understood that steaming-may be required for longer periods of time on. heavier goods than is required on light goods.

after being steamed the goods are passed into a Washer and washed to remove the alkali and to remove the waxy materials and the motes. The wash water may be either hot; or cold andmay contain soap or other penetrants After being treated as above described, the goods are in excellent condition for treatment with bleaching agents.

What is claimed is:

1. The method of treating fibers of vegetable origin prior to bleaching the same which comprises impregnating the fibers with sufiicient of a solution of an alkali to render the fibers damp, permitting the dampened impregnated goods to a d nt e mews r so tened. a d. ar e re. h su ec n t e fib r t l c nt n n solution of alkali to the action of steam 2, The method of treating fibers of; vegetable originp ior to bleaching the same which com- Rr ses m e natin t e b r t suffigint asolution of an alkali to render thefibers darhp, permitting the dampened impregnated goods to an nt ili mew a e ened. an qs a d. and thenheating the fibers still containing alkali under conditions where substantial evaporation of moisture from, the fibers is prevented 3. The method of treating fibers of vegetable Qrigin P3 ch n h? S li ih m.- prises impregnating the fibers with suificient of a solution containing an, alkaliin amount equivalent to about to 60 grams NaOH per liter to render the fibers damp and; permitting the dampenecl impregnated goods to stand until the motes are softened and loosened and then subjecting the fibers containing alkali to theaction of steam."

4. The method of treating fibers of vegetable origin prior to bleaching the same which comprises impregnating the fibers With sufficient oi an aqueous solution containing to 40 grams NaOI-I- per liter to. renderthe fibers damp and permitting the dampened impregnated goods to stand until the motes are softened and loosened and then subjecting the fibers containing alkali to the action of steam.

5. The method of treating fibers of vegetable origin which comprises impregnating the fibers with suificient of a solution of an alkali to render the fibers damp, permitting the so impregnated goods to steep for more than four hours, thereafter steaming the fibers impregnated with alkali for a short period of time and then treating the fibers with a bleaching solution to bleach the same.

6, The method of treating fibers of vegetable origin which comprises impregnating the fibers with sufiicient of an aqueous solution containing alkali equivalent to at least 15 grams NaOH per liter to render the fibers damp, permitting the so dampened impregnated fibers to steep for more than four hours, and thereafter steaming the fibers impregnated with alkali for a short period of time.

7, The method of treating fibers of vegetable origin which comprises impregnating the fibers with sufi cient of an aqueous solution containing caustic soda and sodium silicate to'render the fibers damp, permitting the s -impregnated fibers to steep for'more than four hours, thereafter steaming the fibers impregnated with alkali for a short period of time and then washing the same.

HANS O. KAUF'FMANN. ROBERT L. MCEWEN. EDWARD S. SHANLEY. JOHN R. HOPKINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 674,759 Cross May 21, 1901 333,875 Mather Jan. 5, 1886, 395,55 Drown, Jan. 22, 1839 2,107,297 Kauffmann Feb. 8, 193.8, 2,220,682 Kauffmann Nov. 5, 1949. 1,515,691 Marsden T Nov. 18, 19 2 1 2,226,162 Dubeau Dec. 24, 194 22,67, 18 m l De 3 .9

FOREIGN PAT NTs Number Country Date 13,867 Great Britain 1904 351,217 Great Britain June 25, 1931 20,656 Great Britain 1911 289,742 Germany Jan. 15, 1916:

OTHER REFERENCES Matthews, Bleaching and Related Processes, Chem. Cat, (30., N. Y., 1921, pp. 270-271.

Haller et al., Chemische Technologie der Baumwolle, Julius Springer, Berlin, 1928, pp 24, 25.

Heerman, Enzyklopadie oler Textilchemischen Technologie, Julius Springer, Berlin, 1930, pp. to 82;