US2252732A - Method of treating cellulose textile material - Google Patents

Description

Patented Aug. 19,1941

METHOD OF TREATING OELLULOSE rnxmn MATERIAL Eric Owen Bidgway, Montclair, and William A. Bodenschata, Brooklawn, N. 1., assignors to Ridbo laboratories Incorporated, Nutley, N. 1., acorporation of New Jersey A No Drawing. Application August 17, 1939, Serial No. 290,627

8Claims.

This invention relates to methods of treating cellulose and more particularly to methods of treating and finishing cellulosic textile fibres.

This application is a continuation in part of our applications Serial No. 112,984, filed November 27, 1936, and Serial No, 172,152, filed November 1, 1937,

The invention contemplates improving the qualities of cellulosic textile fibres. For example, material treated in accordance with the invention has an improved appearance, handle, sheerness, increased hot flexing life, and increased tensile strength both at normal and at high temperatures, has substantially no shrinkage, resists wrinkling, mildew; and has greater moisture absorption properties and is more receptive to dyeing than untreated material.

, textile fibres with a water-soluble copper salt and then with a solution containing ammonium hydroxide and one or more alkali hydroxides stronger than ammonium hydroxide, such as sodium hydroxide and/or potassium hydroxide. The concentrations of the water-soluble copper salt and the hydroxides employed are such that only the. lesser celiuloses and other impurities are selectively dissolved and removed, without dissolution of the alpha-cellulose and the resultant disintegration of the fibre; thereby obtaining accurate control of the reacting ingredients at all times. The removal of the impurities has the effect of lessening the diameter of the fibres, and amore sheer fabric is produced; also there is a tendency to unite the random fibres to the fibre they be' in the form of fabrics, knitted or woven,

yarns, cords, threads, fibres or coverings.

The present invention may be employed for the purpose of securing a pattern of contrasting shades of dye simultaneously from the same dye bath. This result may be obtained by printing.

the fabric with one or more of the reagents so that the treatment takes place-only in local portions. An alternative method is to print the fabric with a "resist" before treatment by. our method, so that the reaction will take place only in those portions where there is no substance to resist or inhibit the reaction. In this way, a great variety of efiects may be obtained.

Highly satisfactory results have also been obtained in applying the improved method to fabrics used for insulating purposes, or to the coverings of vwires used for insulating purposes.

The resultant product is an insulating material of higher dielectric constant having a reduced diameter. Furthermore, with the removal of the impurities the cellulosic textile fibres are more porous, thus they may more readily be impregnated with various coating and impregnating agents such as the synthetic resins, varnishes, lacquers, crease-resisting agents, etc., used for the above and other purposes.

In practice a suitable cellulosic textile fibre such as fabrics and yarns, either in the grey or bleached condition, is treated with a solution of bundle through contraction. The treatment of.

' synthetic fibres of cellulose that is. rayon or other regenerated cellulose, in accordance with this invention adds a very distinct and definite appearance and handle which these materials do not otherwise poses in that. after treatment, they have a "liveness and the lustre is someany water-soluble copper salt; for example, saltisfactory results have been obtained by employing copper sulphate, copper nitrate, copper bromide, or copper chloride. The excess salt solution is then removed in any suitable manner,- such as by centrifuging or squeeze rolls, and the fibre is then led into a solution containing ammonium hydroxide and sodium hydroxide, or ammonium hydroxide and any other alkaline hydroxide or mixture of hydroxides stronger than ammonium hydroxide, such as potassium hydroxide. The ratio of water-soluble copper salt to cellulose may be varied, and, likewise, the resultant treatment may be modified, for example, a solution of ammonium hydroxide and a relatively strong solution of sodium hydroxide may be employed, or a solution containing ammonium hydroxide and relatively dilute sodium hydroxide may first be used, and the fibres later passed through a stronger solution of sodium hydroxide. The preferred concentrations and ratios and their limits will be fully set forth hereinafter,

By way of example, 'two types of grey cloth .identified as Indian Head Brown Sheeting and Pequot Heavy Sheeting were treated in accordance with the method of the present invention. .The materials used were given the customary preliminary treatment consisting of treatment in boiling water for several hours and then rinsing in clear water, soaking in an aqueous solution containing an enzyme, for removing starch for four hours at a temperature of 70 C. and then rinsing in clear water, treating in a boiling aqueous solution containing sodium hydroxide (8 grams per litre) and sodium carbonate (1 gram per litre), and then washing, treating with dilute acid and finally rinsing in clear water and dried to constant weight.

The material was then treated in a solution of copper sulphate and thereafter in a solution con taining sodium hydroxide and ammonia. Following this, the material was thoroughly washed in a bath of dilute ammonium hydroxide to remove any dissolved material. The material was then treated in a 5% solution of sulphuric acid to remove any trace of copper and finally rinsed 7 and dried to constant weight to determine the loss due to dissolving of the lesser celluloses and impurities. The correlations of the quantities of reagents used (concentrations), with respect to each other, and with respect to the quantity of material being treated (expression) are shown in the following table:

method herein described shows substantially no shrinkage in warp or weft directions when subjected to repeated launderings, and also retains the lustre and other desirable'qualities received during the treatment.

The invention will be readily understood from the following examples in which certain preferred methods of employing the invention are given, illustrating the range of concentrations of the reagents that may be employed in treating various fabrics, threads, and yarns. Figures and ratios are quoted in terms of copper sulphate (CUSOH2O) for the sake of convenience; the matter of applying the ratios and concentrations according to their copper equivalent in the other water-soluble copper salts is merely a matter of simple calculation; the same applies to the application of the figures quoted for sodium hydroxide to other alkali hydroxides, or mixtures of such hydroxides.

Since the quantity of water-soluble copper salt contained in the fibres determines the ultimate degree of treatment, it is this part of the process that is the most critical and which requires the greatest amount of control. There are a great many different types of cellulosic materials in the form of fabrics and yarns, etc., and thus having different weights per square yard, and we have discovered that there are certain critical copper to cellulose ratios governing the maximum quantity of water-soluble copper salt held in and on the fibres of the various Weight per square yard materials above which dissolved alpha-cellulose is liable to result. In practicing our invention it is highly undesirable that any alphacellulosebe dissolved and precipitated on a fabric or yarn; furthermore, the formation of a film of dissolved cellulose on a fabric or yarn inhibits the treatment of the interior of such material since such a film insulates the material and is rather diflicult to penetrate. The copper/ammonia processes known to us admittedly treat Table 1 Material treated 0 so 5H 0 N on NB Dres- 33. LOSS in 1 a sion weight aria/litre Gma/iitra G'IflS-l/itffl Percent C. .Pe'rce'nt Indian head brOWIL 247. 8 78. 3 137. 18 67 24 1. 31 equ 247. 8 78. 3 137. 18 80 24 1; 16 Indian head brown.. 154 47. 2 164 95 24 l. 01

material other than the lesser celluloses is avoided.

A feature of the invention is the provision of a method of treating cellulosic yarns, threads, fabrics and the like, to make them substantially .unshrinkable in laundering; that is, thematerial will subsequently retain the dimensions set therein during treatment. It has been found that the dimensions of the material can be stretched up to 24% of any one dimension or up to 12% of both dimensions, in the case of fabrics, during treatment and accordingly that the original or desired area will be retained when the material is subjected to the customary washing. Cellulosic material treated in accordance with the only the surface of the exterior fibres by dissolving these surface fibres, relying upon speed and the squeezing out of most of the dissolved alphai cellulose to minimize the damage to the material being treated. A number of these prior art processes deal with a mixture of the three essential ingredients into a single highly active solvent solution, i. e., the copper salt, the sodium hydroxide, and the ammonium hydroxide, which has the effect of mass action on the surface of the fibres of the material being treated.

A particular feature of our process is that it is possible thereby to obtain the maximum of desirable treatment of all the fibres in the material and the interior of the fibres without dissolving alpha-cellulose. We have discovered that the normal tendency of a fabric (or fibres in the form of bundles of yarn such as warps or skeins) to retain trapped excess copper salt solution, likely to cause dissolution of the alpha-cellulose, increases 1 with the fabrics weight per square yard; accordingly, an important feature of our invention is the discovery of a range of copper to cellulose ratios for the various weight per square yard fabrics below which alpha-cellulose will not be dissolved and wherein we are able to obtain the maximum degree of treatment without fear of dissolved alpha-cellulose in the local portions where this excess copper salt is retained. In this way the reaction is always under control since it Table 3 The decimal figures in this table represent the copper (CuSO4.5H2O) to cellulose ratios with respect to the copper sulphate concentration and the percentum of copper sulphate solution remaining in the material, after removal of excess,

cannot proceed beyond the point determined by based on the original dry weight of such material the quantity of copper salt present in and on each (expression).

flg 110% 105% 100% 05% 85% 20% 15% 10% g .2848 .2112 .2510 .2440 .2505 .2110 .2054 .1898 .1152 .2112 .2540 .2508 .2215 .2244 .2112 .1950 .1848 .1115 .2005 .2551 .2420 .2110 .2152 .2054 .1225 .1101. .1668 2618 2493 2368 2244 2119 1994 1870 1745 1520 .2540 2419 2298 2177 2056 1935 1814 1693 1572 2461 2344 2227 2110 1992 1875 .1758 1641 1524 2381 2268 2155 2041 19% 1814 1701 1587. 1474 2302 2192 2082 1973 1863 1754 1644 1534 1425 2%)7 2115 2009 1904 1798 1692 1586 1480 1375 2138 Z136 1934 1832 1731 16%) 1527 1425 1323 .2056 1958 1860 1762 .1664 1566 1468 1371 1273 1972 1878 1784 1690 1596 1502 1109 1315 i221 .1888 .1102 110a .1512 .1522 .1438 .1245 .1259 1100 fibre in the fabric when it comes into contact The ratios for solutions below 200 grams per with the alkali hydroxides.

The following is a table of the copper expressed in terms of CuS045H2O to cellulose ratios ior various fabrics of differing weight per square yard. The ratios so expressed are the upper limits which we desire to employ at room temperatures, such as approximately 20 C. or higher in this method, after the material has been immersed in the copper salt solution; excess CuSO4.5H2O solution above this ratio should be removed from the material before it is subject to treatment in the other reagents.

It will be seen from the foregoing table that the copper to cellulose, in terms or copper sulphate, ratios increases .01 for each added square yard per pound or fabric; thus marquesettes, which are about 15 square yards to the pound, would havea preferred limiting ratio of .3.

The above table represents the upper limits for each type of material which has been kier boiled, malted, and/or bleached, irrespective-of the concentrations of the ammonia and other alkali hydroxides, ortime of immersion. If the fibres or material are in the unbleached or grey state, slightly higher concentrations of the water-soluble copper salt may be employed to produce a similar finish without dissolving alpha cellulose.

The highest practical concentration of copper sulphate solution in terms of grams per litre and expression (percentum of copper sulphate solution remaining in the material after removal or theexcess solution based on the original dry weight of such material) for any oi! the ratios 'set forth in Table 2 can readllybe determined from the following, Table 3:

litre can readily be calculated.

For example, if the highest concentration of copper sulphate solution that may be employed on a 6 square yard per pound material is to be determined, it will be noted in Table 2 that the maximum ratio is .21, and from Table 3 it will be noted that 320 grams per litre copper sulphate solution maybe employed at 75% expression, or a 300 grams per litre solution may be employed at expression. The ranges of copper sulphate concentration which may be employed for various materials, depending upon the type of finish desired, will be apparent from Example 1. However, in no case is it desired to exceed the ratios set forth in Table 2. It is not deemed practica1 or feasible to employ expressions, even with more dilute solutions of copper sulphate, above 110%. with some fabrics it is not practical to employ expressions as low as 65% and in many cases this will depend upon the apparatus available; however, from Table 3 it is apparent that higher expressions may readily be employed with a lower concentration of copper salt solution. For instance, in the illustration given employing 6 square yard per pound material, if the apparatus available is not adapted to supply an even squeeze at 75% expression, the method can be employed at expression with approximately 235 grams per litre copper sulphate solution.

In a slightly modified method, by controlling the temperature, time of immersion, and the concentrations of the alkali hydroxides, copper sulphateto cellulose ratios somewhat higher than those of Table 2 maybe used, without dissolution of the alpha cellulose. These higher ratios may go as far as an extra .05 of C.uS04.5H2O to cellulose for each of the various weight fabrics. This may be determined in the following manher, which covers the whole range of concentra-.

jproportions will cause a corresponding reduction in the total reaction; further, it the time is insuflicient for a selective'absorption of the reagents from a solution in whose total volume more than molecular proportions are present but in a dilute form, the reaction'will not go to for each increase of .01 in the copper sulphate to cellulose ratio above the limits in the foregoing Table 2 (up to .05 in the case of each weight fabric), the concentration of each alkali hydroxide solution must be reduced by 10% below molecular proportion concentrations with respect to the copper salt concentration, and the time of immersion must not exceed three seconds. The most effective molecular proportions being:

CuSO45HzO-1 11161 (249.71) or in parts 1. NaOH 2 mols (80.02) or in parts 0.32

4 mols (68.12) or in parts 0.273

upon which this modified method is based.

The efiiciency of the reaction increases with an increase in the NHs concentration and/or a decrease in the temperature of the hydroxide solution. However, it is not necessary to have the ammonia concentration above 8 mols at room temperature, and 4 mols is preferred. For the purpose of economy, refrigeration may be used in the alkali solution so that proportions below 8 mols of ammonia may be used, with the resultant saving in ammonia. Thus, where 8 mols of NH3 may be used at room temperature of approximately 20 C., l mol of NH3 may be taken off the ammonium hydroxide concentration for each. drop of C. in the temperature of the hydroxide solution. We prefer to use refrigeration in the ammonium hydroxide-alkali hydroxide solution only when the material being treated is well below the copper to cellulose ratio limits previously set forth.

It is believed that the invention will be readily understood from the foregoing description and ratios in conjunction with the following specific examples which are illustrative of our improved method.

Example 1 A light fabric, such as a lawn having a count of threads per inch, both warp and weft, of 68x72 or- 88x80, which is approximately 10 square yards to the pound in the malted and kier boiled and/or bleached state, is led into a solution of copper sulphate and thoroughly impregnated, and

then it is led through squeeze rolls into a solution of ammonium hydroxide and sodium hydroxide and squeezed again through rolls to remove excess.

A. For a soft to a slightly crisp finish, the CuSO45HzO concentration may be up to 150 grams per litre. NaOH concentration up to 48 grams per litre, and N113 concentration up to 82 grams per litre.

B. For a slightly crisp to a crisp finish, the CIISO45H2O' concentration may be from 150 grams to 230 grams per litre. NaOH concentration up to '74 grams per litre, and NH: concentration up to 126 grams per litre.

C. For a crisp to a very crisp or organdy-like finish, the CuSO45H2O concentration may be from 230- grams to 320 grams per litre, NaOH concentration up to 104 grams per litre, and NH3.

concentra ion up to 185 grams per litre.

The percentage of copper sulphate solution remaining in the evenly squeezed fabric after the first step should be below 110% of the weight of the fabric in A and B and, in order to eliminate the possibility of dissolved. alpha cellulose, with 320 grams per litre copper sulphate in C, the percentage remaining should be below 93%.

The higher copper salt concentration apparently prepare the cellulose for a new and distinct action by caustic alkali of mercerizing strength (that is, between 200 and 450 grams per litre NaOH) in such a way that, the fibres having been deflated after the swelling action of the caustic alkali by the usual souring, washing and drying operations, they are condensed in such a way as to make them crisp and to retain their crispness even after repeated launderings.

Forthis reason, when crisp finishes are required, we prefer to lead the fabric directly into caustic alkali of mercerizing strength after it leaves the squeeze rolls from the caustic/ ammonia solution, and thence onto a mercerizing machine. While we have successfully treated the fabric without tension while it contained the caustic alkali, however, we prefer to use tension in this step such as that obtained on any of the standard mercerizing machines. The alkali may be removed from the cloth with water after mercerizing and then the cloth may be soured in a suitable acid such as sulphuric acid, and then washed again to remove the acid.

Thus, the process may be carried out successfully and efiiciently by placing two extra boxes, fitted with adequate squeeze rolls, in tandem with the caustic alkali box on any of the standard mercerizing machines, and the whole process may be carried out continuously.

A certain degree of stiffness or crispness may be obtained by finishing up (that is, washing and souring, washing and drying) the fabric after the caustic/ammonia treatment when the higher concentrations of copper salt solutions are used. This, we believe, is because the lesser celluloses and other impurities, which are probably in the inter-micellular spaces as well as the core of the fibres, are more efliciently removed, and upon drying the alpha cellulose micells in each fibre become more intimately in contact with each other due to the attendant reduction in the diameter of the fibre, However, when the fibres come into contact with strong caustic alkali after the caustic/ammonia step they are in an excellent condition for the swelling action which then takes place, thus, upon deflation with water, souring, washing and drying, they are able to still further deflate themselves, closing in on the spaces left by the removal of the impurities, so that each fibre is apparently a more condensed and homogeneous mass of alpha cellulose of smaller diameter; the result being that a. beautifully sheer, crisp, and lustrous fabric is obtained, and one which takes dyes definitely deeper and better than a fabric which has merely been thoroughly mercerized and bleached in the usual manner.

The application of the method to other weight fabrics is readily apparent from the foregoing example in conjunction with the ratios expressed on page 3.

Example 2 In a slightly modified method the cellulosic fibres are wetted with a copper sulphate solution (CuS04.5H-2O) of approximately 158 grams per litre, and centrifuged. or squeezed until the remaining material is approximately double the weight of the original dry mass. The fibres may then be introduced into an ammonium hydroxide and sodium hydroxide solution of approximately grams of NH; per litre and 50 grams of NaOH per litre and are then stretched and introduced into a solution of sodium hydroxide of approxi- .alkalies and dissolve the copper.

is then washed with hot or cold water until free of alkalinity. Thereafter the fibres are first washed in a dilute solution of sulphuric acid, for example, 60 grams per litre, and again washed in a solution of sulphuric acid of approximately 25 grams per litre. The acid is then removed by washing in water and the fibres dried in any suitable fashion, for example, by air, 7

In order to be set in such a wayas to render the fabric substantially unshrinkable, the second mentioned treatment with sodium hydroxide is made when the fabric is in a stretched condition. Therefore, the fabric is preferably stretched warpwise and fillingwise between and 12 above the original grey sizes or the-material may be stretched in any one direction up to 24% of its original dimension, immediately after it has been treated in the ammonia-caustic soda.- solution, at which time itis in a somewhat plastic condition and may therefore be more easily stretched both weftwise and warpwise to a point greater than its original size.

It is not necessary to remove the alkali hydroxides nor the copper before the subsequent treatment with sodium-hydroxide. The treatment for shrinkproof qualities preferably requires that the alkaline hydroxides be removed while the cloth is in a stretched condition in order to set the desired dimensions; they may be removed by either washing with water, by

- phate neutralizing, or both. In the interest of economy it is desirable that most, if not all, of the alkali hydroxides beremoved with water, thus enabling them to be easily recovered by well-known methods, such as by evaporation.

It should be noted that the dimensions of the cloth at the time the sodium hydroxide is applied do not remain after the tension is reduced, the fabric is stretched to a definite excess stretch (depending upon the condition of the cloth, and type of cloth, and the desired finished dimensions). For example, if the grey dimensions are desired in the finished goods, the cloth is treated in the grey State and stretched to approximately 11%% greater than its grey measurement both warpwise and weftwise before treatment with the sodium hydroxide, and this excess stretch is maintained until the fabric has been freed of the alkaline hydroxides.

Example 3 ed to reduce the surface tension of cotton fibres.

After the fibres are wetted. the excess copper sulphate solution and the wetting agent are removed by an air blast or centrifuging, until the expression of copper solution remaining on the fibres is approximately 100% of the dry weight of .the fibres, the fibres are treated with a solution containing ammonium hydroxide and sodium hydroxide having a reduced caustic alkali content so as to inhibit the swelling and shrinking of the fibres. The fibres are again dried and introduced into a dilute sulphuric acid solution of about 60 grams of acid per litre to neutralize the The fibres are again washed in a weak solution of sulphuric acid of about grams of acid per litre to complete the removal of the copper. Thereafter, the treated material may be washed with water to remove the acid, and dried. A copper sulsolution containing 76 grams of CuSO4.5H-.-O per litre is satisfactory, and the ammonium hydroxide and sodium hydroxide solution may contain 68 grams of NH: per litre and 7 grams of NaOH per litre. If a wooly fibre is desired, the above specified concentrations may be increased."

, Example 4 This modification contemplates treating cellulosic textile fibres in such manner that their hot flexing life and hot tensile strength is notably increased. In this method, fibres are first saturated with a solution of copper sulphate and then in a solution of ammonium hydroxide and sodium hydroxide; the concentrations of said solutions and the time of treatment are such that the impuritiesvin the cellulosic fibres such as sugars,

glucosides and the like, are substantially completely dissolved and removed from the fibres. The cellulosic textile fibres are then freed of the copper and alkaline hydroxides in dilute acid baths and the fibres washed in water, and if they are in a combined form, dried under tension to the desired dimensions. Satisfactory results have been obtained when the CllSO4.5H2O to cellulose ratio is- .25 to 1, and, after the excess copper sulphate has been removed, the copper solution remaining in the fibres not exceeding their original dry weight by more than 110%, the C11S04.5H2O to NaOH ratio on the fibres is 1 to .32. The NHa content may vary from 80 to 132 grams per litre. The treated cellulosic fibres are then washed, first in a dilute sulphuric acid bath of about 60 grams or acid to neutralize the hydroxides and to dissolve the copper, andin a' second acid bath of about 25 grams of sulphuric acid per litre. The acid is then removed by washing in water and the fibres dried under tension to the desired. dimensions.

Example 5 This modification contemplates treating cellulosic textile fibres in such a manner as to increase the tensile strength both at low and high temperatures and to improve their appearance and absorption of dyestuffs. More particularly we have in mind the treatment of fibres whether in any of the various stages prior to baths, and the fibres washed in water. In the phate containing 158 grams of copper sulphate- (ousoasrnm per litre, the excess solution being removed by well-known methods such as squeezing through nip rolls or centrifuging until the copper sulphate ratio to cellulose is below .145 and the residual solution in the fibres is not in excess of approximately 100% of the dry weight of the material being treated; and then treated in a solution containing 100 grams of ammonia (NHa) per litre and 30 grams of sodium hydroxide (NaOH) per litre.

It is to be understood that the foregoing examples setting forth specific materials, weights and proportions, are given for the purpose only of illustrating the invention, and that our invention is not limited thereto but contemplates such other and further modifications and changes which may become apparent to those skilled in the art and which are inherently possessed herein. It is now believed that in describingthe operation of our invention, and the delineation of the examples, the same has become thoroughly apparent as well as the new products resulting therefrom.

We claim:

1. The method of treating cellulosic textile material to selectively dissolve and remove therefrom the lesser celluloses, sugars, glucosides and other impurities without dissolving the alpha cellulose content thereof, which comprises the steps of first thoroughly impregnating the material with a solution of a. water-soluble copper salt,

removing excess copper salt solution from the material so that the quantity of the copper salt remaining on the material does not exceed, in terms of CHSO4.5H2O, 1 part of copper salt to 4 parts of cellulosic material for average lightweight materials such as those weighing 1 pound per square yards, with proportionately smaller ratios of copper salt for heavier materials the ratio of copper sulphate to cellulose being reduced .01 in heavier fabrics for each lessened square yard per pound of material being treated, then treating the material in a solution of ammonium hydroxide and an alkali metal hydroxide having a basicity greater than ammonium dissolving the alpha cellulose content thereof, which comprises first thoroughly impregnating the material in a solution of copper sulphate, removing excess solution from the material until the ratio of copper sulphate to cellulose is such that alpha cellulose" will not be dissolved upon subsequent treatment, for fabrics comprising one square yard per pound the ratio of copper sulphate (CUSO45H2O) to cellulose being not in excess of .16, said ratio increasing .01 for each added square yard per pound of cellulosic material, then treating the impregnated material in a solution containing ammonium hydroxide and an alkali metal hydroxide having a basicity greater than ammonium hydroxide, and then washing the material to remove the reagents and dissolved impurities.

4. The method of treating cellulosic textile material to remove therefrom the lesser celluloses, sugars, glucosides and other impurities without dissolving the alpha cellulose content thereof, which comprises the steps'of first thoroughly impregnating thematerial in a solution of copper sulphate, removing excess solution from the material until the ratio of copper sulphate to cellulose is such that alpha cellulose will not be dissolved upon subsequent treatment, for'fabrics comprising one square yard per pound the ratio hydroxide, and finally washing the material to remove the reagents and the aforesaid selectively dissolved impurities.

2. A method of treating cellulosic textile material to remove therefrom, the lesser celluloses, sugars, glucosides and other impurities, without dissolving the alpha cellulose content thereof, which comprises first thoroughly impregnating the material in a solution of copper sulphate, the concentration of the copper sulphate solution retained in the material being varied in accordance with the character of the material under treatment, a relatively high concentration 'kali metal hydroxide, the quantity of alkaline hydroxide other than ammonium hydroxide employed preferably being in the ratio of at least approximately 1 part of alkaline hydroxide to 3 parts of copper sulphate on the material, and finally washing the material to remove the reagents. e

3. The method of treating cellulosic textile material to remove therefrom the lesser celluloses, sugars, glucosides and other impurities without of copper sulphate (CllSO45H2O) to cellulose being within the range of .16 to .21, the range of said ratios increasing .01 for each added square yard per pound of cellulosic material, then treating the impregnated material for a period not exceeding three seconds in a solution containing ammonium hydroxide and an alkali metal hydroxide having a basicity greater than ammonium hydroxide, the concentration of the alkaline solutions being reduced 10% below molecular proportions with respect to each .01 increase in the copper sulphate to cellulose ratio based on the ratio of .16 for fabrics comprising one square yard per pound and the increased ratio for lighter fabrics, and then washing the material to remove the reagents and dissolved impurities.

5. The method of treating cellulosic textile material to remove therefrom. the lesser celluloses, sugars, glucosides and other impurities without dissolving the alpha cellulose content thereof, which comprises first impregnating the material in a solution of copper sulphate, removing excess solution from the material until the ratio of copper sulphate to cellulose is such that alpha cellulose will not be dissolved upon subsequent treatment, for fabrics comprising 1 square yard per pound, the ratio of copper sulphate (CuSO45H2O) to cellulose being below .16, saidratio increasing .01 for each addedsquare yard per pound of cellulosic material, then treating the impregnated material in a solution containing ammonium hydroxide and an alkali metal hydroxide having a basicity greater than ammonium hydroxide, the ammonia (Nm) concentration being 8 mols of ammonia to 1 of copper sulphate at solution temperatures of approximately 20 C., the concentration of ammonia being reduced 1 mol for each 5 0. reduction in solution temperature from 20 C'., and then washing the material to remove the reagents and dissolved impurities.

6. The method of treating cellulosic textile material to improve the quality thereof and to render it substantially unshrinkable, which comprises thoroughly wetting said material in a solution of a water-soluble copper salt of a con centration inadequate to cause the dissolution of the alpha cellulose during the treatment, but suiiicient to remove the lesser colluloses such as sugars glucosides and other impurities; removing the excess solution from said material so that for fabrics comprising one square yard per pound the ratio of copper salt to cellulose is not in excess .16, said ratio increasing .01 for each added square yard per pound of cellulosic material, and then subjecting the material to the action of-a solution of ammonium hydroxide and dilute sodium hydroxide, stretching the material to the desired dimensions up to 24% of any one dimension or up to 12% of both dimensions, and then subjecting said material to the action of a solution of sodium hydroxide of a mercerizing concentration, washing said material in water to remove the 'alkalies, then removing the tension on said material, and then washing said material in a dilute acid solution to remove copper, thereby recovering said reagents.

7. I'he method of treating cellulosic textile material to remove therefrom the lesser celluloses,

sugars, glucosides and other impurities without dissolving the alpha cellulose content thereof, which comprises first thoroughly impregnating the material in a solution of copper sulphate, removing excess solution from the material until the ratio of copper sulphate to cellulose is such that 'alpha cellulose will not be dissolved upon subsequent treatment, for fabrics comprising one square yard per pound the ratio of copper sulphate (CuSO45HzO) to cellulose being not in excessof .16, theconcentration of the copper sulphate solution being not in excess of approximately 285 grams of CuSO45H2O per litre, said ratio increasing .01 and the maximum permissible concentration of copper sulphate solution also being increased for each added square yard per pound of cellulosic material, then treating the impregnated material in a solution containing ammonium hydroxide and an alkali metal hydroxide having a basicity greater than ammonium hydroxide, and then washing the material to remove the reagentsand dissolved impurities.

8. The method of treating cellulosic textile material to remove therefrom the lesser celluloses, sugars, glucosides and other impurities withoutdissolving the alpha cellulose content thereof, which comprises first thoroughly impregnating the material in a solution of copper sulphate, removing excess solution fromthe material until the ratio of copper sulphate on the material to cellulose is such that alpha cellulose will not be approximately 285 grams of CuSO45HzO per litre,

said ratio andthe maximum permissible concentration of copper sulphate solution being increased relatively for lighter weight fabrics said ratio being increased approximately .01 for each additional square yard of material per pound,

WILLIAM A. BODENSCHATZ. ERIC OW'EN' RIDGWAY.