US2093651A

US2093651A - Dyeing fibrous materials

Info

Publication number: US2093651A
Application number: US656024A
Authority: US
Inventors: Gustave A Widmer; Edward W Pierce
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-02-09
Filing date: 1933-02-09
Publication date: 1937-09-21
Anticipated expiration: 1954-09-21
Also published as: GB433143A; FR768282A; GB433210A; DE646529C; FR769307A

Description

Patented Sept. 21, 1931 2,093,651

nmmc muons MATERIALS Gustave A. Widmer, Philadelphia, Pa., and Edward W. Pierce, Clifton, N. J.

. No Drawing. Application February 9, 1933,

Serial No. 656,024

14 Claims. (Cl. 8-5) It has been proposed to impregnate cotton or material with car'bamide-formaidehyde comrayon fabrics with diluted aqueous solutions of pounds and dyeing or printing, applying reserves urea-formaldehyde condensation products with or ihtensifiers, as indicated in the examples given the purpose of producing an anti-crease effect below, which examples will serve to demonstrate after suitable curing and processing. some of the many feasible ways of practicing the It has been found that carbamide-formaldeinvention. hyde compounds if properly processed, produce As materials to be impregnated, all kinds of unexpected and useful results in the dyeing art, cellulosic fibrous material can be used,--cotton, and this application is a description of the new rayon, linen, jute, ramie, etc., in form of sheets 10 processes and products developed by using such (fabrics or paper), spun in form of yarn, or loose 10 compounds as a fixing agent for dyestuffs and fibre. Most practical however is the sheet form pigments. where a continuous process can be used to bring These processes can be classed into two groups, about the impregnation by immersion, dipping, both of which however cover fixing coloring matbrushing, printing, spraying, etc.

5 ters, but the first group comprises processes in The impregnation step may be carried out by which acid dyes, wool or silk dyes, and the like a simple dipping and squeezing operation, leaving are used which possess a chemical aflinity in the fabric or other fibrous material the desired for heat-treated carbamide-formaldehyde comamount of carbamide-formaldehyde compound. pounds and wherein the dye is therefore chemi- If the bath contains at the same time, an acid cally afilxed. The second group comprises procdye, the dye is chemically affixed by the carba- 20 esses using pigments, metal powders or finely dinude-formaldehyde compound by heat-treating vided insoluble dyes, the carbamide-formaldehyde the material afterwards and thereby making it compounds acting as an insoluble binder, afllxinsoluble in water and solvents. If the impreging these pigments mechanically. Combinations nation is done with the soluble carbamide-formof the processes taken from both groups respecaldehyde compound, it may be heat-treated and 25 tively are possible. then dyed subsequently in the usual manner with All these processes have one common feature: an acid dye, or it may be printed in various ways. an aqueous or aqueous-alcoholic solution of a Reserves" may be printed on, for example incarbamide-formaldehyde compound is used for organic bases like sodium hydroxide, barium hyimpregnating the fibrous material to be dyed, and droxide, etc. These substances prevent the 30 thereafter the material is dried, usually at a modproper reaction from taking place during the heat crate temperature. Then the soluble carbamidetreatment of impregnatedmaterial, so that upon formaldehyde compound which is deposited dursubsequent dyeing the printed places show no afing the drying operation,in, on and around the finity for the acid dye and therefore remain white fibres is converted into its insoluble form by apor nearly so. 35

' plying a suitable heat treatment. This insoluble Instead of "reserves, intensifiers" may be form is the final form of the product and posprinted on the impregnated material. Organic sesses surprising properties. bases of the type of methylamine, ethylene di- The insoluble carbamide-formaldehyde product amine, etc., may be used for this purpose. Very 40 is found to have a decided affinity for acid dyes surprising is also that hexamethylenetetramine 40 as they are usually used for dyeing wool or silk, and other ammonium compounds, like ammonii. e., animal fibres. In other words: after propum acetate act as intensifiers, whereas i'ree erly processing a fibrous material, for instance ammonia acts as a reserve. By the use of some cotton fabric, with a carbamide-formaldehyde of these "intensifiers the strength of the color compound and thereafter transforming it into is greatly enhanced, much stronger than without its insoluble form it can be dyed with the same them, due to increased selective aifinity for acid dyesas wool or silk. This fact offers great posdyes. sibilities because, in many cases the wool dyes Simultaneously with "intensifiers or "reserves are considerably cheaper and light-faster than other suitable dyestuffs may be printed on imdirect cotton dyes, and in other cases a brilliancy pregnated material and thereby by proper procof shade is obtainable not to be produced with essing multicolor effects be produced. direct cotton dyes. The heat treatment of the impregnated fibrous Many modifications of this process can be used material which converts the carbamide-formaldein order to bring about this same result, by subhyde compound from the soluble into the insoluble sequent 'or simultaneous impregnation of fibrous form may be applied in different ways. The ma- 5 terial may for instance be steamed after impregnation in the steaming equipment commercially used in dyeing plants, where it is heated in pres ence of steam at temperaturesover degrees C. under pressure. Or the material may if it is in sheet form, be subjected to the influence of dry heat, bringing it into contact with a hot plate heated to to 170 degrees C., or carrying it slowly in a continuous way over the surface of a hot roll or a steam cylinder heated to about the above-mentioned temperatures.

The carbamide-formaldehyde compounds are transformed into their insoluble form according to their properties under somewhat different conditions. Dimethylolurea, mixtures of monoand dimethylolurea, or mono-methylolurea as well as their more advanced condensation stages have been found to require for instance two minutes at 165 degrees C. or 20 minutes at 130 degrees C., in order to secure good results, that is, to assure that the greatest part of the compound remains in the fibrous material after boiling with a diluted soap solution.

Mixtures of methylolurea and methylolthiourea, or their more advanced condensation stages, have been found to require a somewhat shorter heat treatment, especially if there is not too much methylolthiourea compound present.

The heat treatment may be carried out in acid, neutral, or basic solution. Advantageously organic acids are used as for instance, acetic acid, formic acid, tartaric acid or the like. If the use of inorganic acid is contemplated, very weak acids should be taken as for instance carbonic acid or boric acid, because of the detrimental effect of the strong inorganic acids to, cellulose when heated. (Carbonizing effect.)

It has been found that the heat treatment in perfectly neutral solutions requires a slightly longer time, but produces the same results as the heat treatment in acid solution.

The heat treatment in basic solution produces results, which are not normal, as indicated above. In presence of inorganic bases like sodium hydroxide etc., the carbamide-formaldehyde products do not get insoluble and subsequent soaping removes them: They act as reserves. In presence of organic bases like ethylene diamine, etc., the heat treatment produces an increased affinity for acid dyes; they act as intensifiers.

The desirable characteristics are obtained at their maximum when the amount of insoluble carbamide-formaldehyde compound is about ten to thirty per cent of the weight of the fibrous material. Under ten per cent the desirable properties disappear slowly, and over thirty per cent the material gets increasingly harsher and eventually stiffer. But in presence of the proper amount the material is not of decreased textile value but rather shows improved textile characteristics.

Instead of carbamide-formaldehyde products in their narrower sense, namely, urea-formaldehyde products, also the corresponding formaldehyde products of substituted ureas, like methylurea, phenylurea, dicyan-diamide, biuret, etc., or urea. homologues like thiourea or guanidine -may be used, or mixtures thereof. Mixtures of some urea, biuret, guanidine, cyanuricacid etc., obtained by decomposing urea by heat at about 160 C., are also very suitable.

While some of the above substances operate very well in their pure form, and even show increased afflnity for acid dyes, like for example, thiourea-formaldehyde compounds, dicyandiamide formaldehyde compounds, formaldehyde compounds of heat-treated urea, etc., they very often enhance also the desirable characteristics of the final product, when used in admixture with urea-formaldehyde products. This is particularly so with thiourea,. and dicyan-diamide.

Thiourea is particularly interesting due to the very greatly increased afilnity it imparts to the celiulosic material. But dicyan-diamide, guanidine and heat-treated urea also produce markedly increased affinity for acid dyes in comparison to urea compounds alone.

The processes indicated above areas a matter of course capable of an infinite number of variations according to the composition of impregnating material, the material, the dyestuff, or the method of dyeing, etc. This same applies to the processes disclosed below in which primarily the mechanical fixing property of such carbamideformaldehyde compounds is contemplated.

It has been found that carbamide-formaldehyde compounds in their soluble stage are easily incorporated in mixtures containing pigments, such as ultramarine, carbon black, etc., or metal powders like aluminum powder. In a. similar manner it is easy to incorporate organic color pigments, color lakes, water insoluble dyes, as for instance nigrosine (spirit soluble), aniline black, oxidized vat dyes (like indigo), and other finely divided insoluble coloring matter. After preparing such mixtures with carbamide-formaldehyde compounds, advantageously in form of suspensions or pastes,'fibrous materials are treated therewith by an impregnation or printing operation. After subsequent drying and heat-treating, the finely divided coloring matter is firmly affixed to the treated fibres, because the color particles are imbedded in the colorless insoluble earbamide-formaldehyde compound acting as a binder. Wash-fast dyeings and printings with pigments of highest light resistance can thereby be cheaply produced,a result heretofore impossible.

This process relating to mechanical afiixing of finely divided coloring matter may be applied to all kinds of fibrous materials, not only cellulose but also wool or silk. The process is particularly adaptable to such materials in sheet form, which allows easy impregnation by immersion, dipping, brushing, printing, spraying, etc. in such form namely as a fabric or paper, can then be processed in a continuous way. Such paper has for instance use for wall paper and the like, due to its wash and light fastness.

As a matter of course reserves can also be applied in this process which result in washing the insoluble coloring matter out after heattreatment by hot soaping, leaving white places.

It is evident from the foregoing general discussion, as well as from the several specific examples hereinafter set forth, that the present invention is by no means limited to the urea-formaldehyde condensation product, but that it envisages condensation products of formaldehyde and derivatives and/or homologues of urea, such as methyl urea, biuret, phenyl urea, dicyan-diamide, biuret, guanylurea, thiourea, guanidine, etc.

The following examples illustrate some of the many ways of carrying out the invention.

Example 1 An impregnation solution is made up as follows: 30 gm. of dry dimethylolurea are dissolved in cc. warm water and the solution brought up to 200 cc., i. e., strength. The-pH value is adjusted to pH=4.5 by adding acetic acid and cotton cloth is immersed therein for a few minutes. The cloth is squeezed out to 100% expression (i. e., the weight of the wet impregnated cloth is 100% more than the original dry cloth). Then it is air-dried and heat-treated by ironing with a hot iron for 2 minutes. The cloth is now out into suitable pieces for dyeing.

(a) cc. of a 4% solution of Kiton fast yellow 3G (Color Index 645) is diluted to 200 cc.

1 then 1 cc. of formic acid is added and the temperature raised to 130 F. A piece of the above treated cotton fabric is dyed in this bath for 20 minutes, rinsed in water and dried. The resultant color is a medium'strong yellow, whereas the untreated, unimpregnated sample, dyed under the same conditions is almost white.

Exactly inan analogous manner further samples of the impregnated heat-treated cotton fabric are dyed with (b) Alizarine Sapphire Blue GS (c) Kiton Fast Red 4 BL (C. 1. Sup. Pg. 44).

The results of b and c are analogous to Example a.

(d) Alizarine Sapphire Blue GS is dyed on a crepe-rayon fabric which was previously treated as the cotton cloth. It is dyed a blue of medium strength whereas the untreated rayon sample dyes a very light tint.

Example 2 (a) A sample of cotton cloth impregnated as described in Example 1 is, before heat-treating it, printed with a printing paste containing 95% British gum (the commercially available printing paste, consisting of cooked starch) and 5% ethylene diamine. The print is then air-dried and heat-treated by hot ironing .for 2 minutes.

A dyestuff solution is now made up as follows: 20 cc. of a V4% solution of Alizarine Sapphire Blue GS are diluted to 200 cc. and 1 cc. of formic acid added. The printed and heat-treated cloth is now dyed for %'of an hour at 120-130 F. rinsed and dried.

Very surprisingly the printed places appear in a deep blue shade, indicating that ethylene diamine intensifies the affinity of the carbamide compound for this acid dye, and does not act as a reserve, as expected. A sample of this printed cloth was exposed 42 hours to the influence of artificial sunlight in the Atlas Fadeometer. The light bluish tinted ground faded somewhat and the heavy blue'design remained practically un- Example 3 Cotton fabric samples are immersed in the following solutions:

(a) solution of dimethylolurea D (b) 25% solution of an equimolecular mixture of monoand dimethylolurea (c) 25% solution of monomethylolurea (11) Water.

The samples are then expressed to 100% (double weight), and after air-drying heat-treated on a hot plate between paper layers 3 minutes at about 320 F. Then each sample is dyed separately in a bath containing 20 cc. of Alizarine Sapphire Blue GSin 200 cc. water plus 1 cc. formic acid, of an hour at 130 F. Then rinsed and dried.

Sample d (blank sample) is dyed a very faint tint of blue, samples c, b and a are increasingly deeper blue,--sample a impregnated with dimethylolurea is the strongest blue.

None of these solutions have been acidified, which insures better stability of the methylolurea solutions. They remain clear and stable for" a much longer time than the acidified solutions of methylolurea, which latter become turbid after about A of an hour.

Example 4 To 100 cc. of a 15% solution of dimethylolurea there is added 25 cc. of a solution of Alizarine Sapphire Blue. A sample of cotton cloth is immersed therein and after air-drying, heat-treated for 2 minutes on a hot plate at about 320 F. It is'then soaped in hot 1% soap solution and shows after rinsing and drying a medium blue of very good wash fastness.

Example 5 A printing paste is prepared as follows:

. Grams Alizarine Sapphire Blue GS 2 Tartaric acid 1 Dimethylolurea dry 12.5

Water 36 British gum 48.5

Total 100.

With this paste a plain cotton cloth is printed, air-dried and steamed for V hour at 12 pounds per square inch steam pressure in a laboratory steambox.

0n soaping a portion of the sample in 1% soap solution 'at about 170 F. it bleeds somewhat, which'shows that the heat treatment is not quite sufiicient.

Therefore another portion of the steam-treated sample is further heated 2 minutes at 320 F. A

soapin'g test of this sample shows not a trace of bleeding which indicates that the heat treatment was complete. A sample treated as lastdescribed was exposed in the Atlas Fadeometer 42 hours to the influence of artificial sunlight. It does not show any fading. This indicates that the lightfastness of this dye is here on cotton Just as good as if the dyestuff was used on wool.

A cotton fabric is printed with the above paste, air-dried, and then heat-treated on a hot plate 2 minutes at 320 F. -The soaping test shows no bleeding, which indicates that the pigment is firmly, mechanically aflixed to thefibre.

(a) A silk fabric is printed with the above paste and thereafter air-dried, heat-treated for 2 minutes at 330 F. and then soaped for 10 minutes at 140 F. in 1% soap solution. The lampblack' is firmly, mechanically afllxed to the silk fabric, and the design is very sharp, as no bleeding ocours on soaping.

(b) Exactly in an analogous manner a piece of cotton fabric is printed with the above lampblack-dimethylolurea suspension with the same result as above. Also here no bleeding occurs in the soaping operation.

With the same printing paste, bleached sulphite paper sheets, or better bleached kraft paper or other suitable paper stock is printed. After air-drying, and subsequent heat-treatment on a hot plate for 2 minutes at 330 F., the pigment is very well mechanically afllxed to the paper. Such printed paper may find application as an improved wallpaper or for similar purposes.

Example 8 Bleached cotton yarn is impregnated with a 25% solution of dimethylolthiourea having a pH value of 4.5 (acetic acid being added to the neutral solution). The yarn is squeezed to 100% expression (double original weight), and after air-drying placed in an electric oven for 45 minutes at 126 C. Then it is dyed together with an untreated sample of the same yarn, with 1% Clothfast Orange G, conc. (CIBA) (C. I. Sup. Pg. 35) under addition of formic acid for hour at 130 F. Then rinsed and dried. The untreated sample is dyed a very faint orange, almost white. The treated sample is dyed a deep full orange shade, which color does not bleed on rinsing.

Example 9 An impregnation solution is prepared as follows:

12 gm. dimethylolurea and 3 gm. thiourea are dissolved to a total volume of 100 cc. In this solution a cotton fabric is dipped, expressed to 100% (double weight) and after air-drying, heattreated on a hot plate 2 minutes at 330 F. The material is then dyed with 1% Alizarine Sapphire Blue GS (on the weight of the fabric) in presence of 10% formic acid for 45 minutes at 130 F., rinsed and dried. Avery deep shade of blue is obtained, much deeper than with the use of dimethylolurea alone and of course still deeper in comparison with material not treated with carbamide-formaldehyde compounds.

Example 10 On a green vat dyed cotton fabric there is printed a design with the following paste:

The fabric is then air-dried and heat-treated 2 minutesat 330 F. Then it is soaped in a soap solution for 10 minutes at 140 F. The result is a splendid fixation of the white pigment on the green background. No noticeable loss of pigment occurs during the soaping.

Example 11 Four samples of cotton fabric are dyed for 45 minutes at boiling temperature with 1% of Direct Violet 3R (CIBA) in presence of 10% common salt, both amounts calculated on the weight of the fabric. Then the samples are rinsed and dried and the resultant color is a deep bluish red. (Sample a.) 7

Three samples are now immersed in a bath of dimethylolurea and expressed to 100% (twice the original weight). The color bleeds very badly on this operation, and after air-drying the color of the samples is a medium bluish red. (Sample 22.)

The two remaining samples are now heattreated for 2 minutes at 330 F. and the resultant color (sample c) is a somewhat deeper bluish red than sample b.

The last sample is now soapecl for 10 minutes in a soap solution at 140 F'., then rinsed and dried. (Sample d.) No bleeding occurs during the soaping operation, and the shade of the finished sample is in strength like sample 0.

Direct Violet 3R which is used in this experiment, is notoriously poor to washing and to be an exceptionally bad bleeding dyestuff if used on cotton. It will be noted, thatthe dyestuff, remaining in the fabric in this experiment, becomes not only fast to washing, but also to soaping, after the imp egnation with dimethylolurea and subsequent heat-treatment.

Example 12 Four printing pastes are prepared as follows:

(a) 15 gm. dimethylolurea, 45 gm. water, 40 gm. British gum. No furtheradditions. Total 100 gm.

(b) 15 gm. dimethylolurea, 42 gm. water, 39.7

gm. British gum, 3.3 gm. ethylamineof 33%.

strength. Total 100 gm.

(c) 15 gm. dimethylolurea, 39.7 gm. water, 40 gm. British gum, 1 gm. methylamine in form of the acetate (Prepared by over-neutralizing 3.3 gm. (33%) methylamine solution with acetic acid to a pH=5.0.) Total 100 gm.

(d) 15 gm. dimethylolurea, 39.7 gm. water, 40 gm. British gum, '1 gm. ethylamine in form of hexamethylenetetra-ethylamine. (Prepared by adding the corresponding amount of formaldehyde to 3.3 gm. (33%) solution of ethylamine.) Total 100 gm.

With each of these pastes a cotton cloth sample is printed, air-dried and heat-treated 2 minutes at 330 F. Then the samples, weighing 4 gm. each, are dyed separately but in the same manner 10 cc. of Alizarlne Sapphire Blue GS (0.62% calculated on the weight of the fabric) and 1 cc. formic acid for hour at 130 F. After soaping for 10 minutes at 140 F. in soap solution, rinsing and drying, the following results are obtained.

In all samples the untreated base is dyed a very faint blue, and in all samples the printed design is dyed a much darker blue shade. The strength of the blue is deepest in experiments 0 and d. The strength of b is somewhat lighter, and the strength of a is again somewhat lighter than D. It appears, therefore, that the used amines or amine compounds are acting as intensifiers.

Example 13 a solution is then diluted to 25% with water. The

cloth' is then expressed to 100% (double original weight) air-dried and heat-treated on a. hot plate for 2 minutes at 330 F. The fabric is then dyed with 1% Clothfast Orange G, conc. (CIBA), (Cale. on weight of sample) and 10% formic acid for hour at 130 F. The result is a medium strength of orange, much deeper than is obtained without impregnation.

Example 14 A sample of linen fabric is impregnated with a 25% solution, containing 20% dimethylolurea and 5% dimethylolthiourea dissolved in water. The fabric is then air-dried and heat-treated 2 minutes at 330 F. on a hot plate. The linen sample is now dyed, simultaneously with an unimpregnated sample with 1% Clothfast Orange G, conc. (CIBA) and 10% formic acid, (calc. on the weight of the sample) for 45 minutes at 130 F., then rinsed and dried-The impregnated linen dyes a very deep, full shade orange, while the untreated linen sample is practicall undyed and shows only a very faint tint.

Example 15 (b) 84 gm. of dicyan-diamide and 243 cc. of

formaldehyde (37% vol.) are reacted at 100 C. for about 10 minutes. The clear solution is then diluted to about 25% strength by bringing the total volume with water to 700 cc.

(c) 300 gm. urea are heated to 160-170 C. for 12 hours, until the foaming, caused by escaping ammonia has almost ceased. 18.5 gm. of the white residue is reacted with 47.3 cc. of formaldehyde (37% vol.) for about 15 minutes and the slightly turbid solution is filtered and diluted with water to about 25% strength by bringing the total volume to 148 cc.

(d) A 25% solution of carbamide-formaldehyde products is prepared by dissolving 20 gm.

dimethylolurea in 60 cc. water and adding thereto 20 cc. of the guanidine formaldehyde product solution as described in this example under a.

(e) A 25% solution of carbamide-formaldehyde products is prepared by dissolving 20 gm. dimethylolurea in 60 cc. water and adding, thereto 20 cc. of the solution b in this example, containing 5 gm. of the dicyan-diamide formaldehyde comprising urea, biuret,

Cottonfabric samples are immersed in the above solutions and after expression to the double original weight, heat-treated on a hot plate for 2 minutes at 330 F. Then they are soaped for 5 minutes at C. in a soap solution, rinsed and dried.

The samples A-F impregnated with the solutions a, j respectively, are now dyedg separately but under the same conditions with 1% Benzylgreen B conc. (CIBA), (Color Index 667) calc. on the weight of the samples, and 10% formic acid at F. for 30 minutes.

Results still very much deeper colored than an untreated sample under the same conditions which produces only a very faint green tint.

The foregoing description and examples, it is understood, are merely illustrative of the invention and in nowise limiting, as the invention includes all modifications fairly within the scope of the appended claims.

The invention is not limited to the "particular substances, quantities, temperatures or mode of procedure, as described, all or any of which may be varied without going beyond the scope of the invention as described and claimed.

We claim:

1. A dye fixing agent'comprising a heat-treated formaldehyde condensation product of the mixture obtained by theheat treatment of urea and comprising urea, biuret, cyanuric acid and guanidine.

2. A printing mixture for cellulosic materials comprising a wool or silk dye and the initial condensation products of formaldehyde with a mixture obtained by the heat treatment of urea and cyanuric acid and guanidine.

3. A dye fixing agent comprising a heat-treated compound obtained from the condensation of formaldehyde with a mixture of substances produced by subjecting urea to partial thermal decomposition at a temperature of about C.

4. A process for dyeing cotton, rayon or other fibrous materials with a wool or silk dye comprising aflixing the dye by a heat treatment of the fibrous material in presence of the products obtained by the reaction between formaldehyde and the products of the partial thermal decomposition of urea at a temperature of about 160 C.

5. A colored fibrous cellulosic material wherein a wool or silk dye is chemically affixed with a heat treated substance resulting from the condensation of formaldehyde with a mixture comprising biuret, cyanuric acid, 'guanidine and urea and obtained by subjecting urea to a heat-treatment at a temperature of about 160 C.

6. A dyeing mixture for cellulosic materials comprising a wool or silk dye and the initial condensation products of formaldehyde with a mixture of substances obtained by subjecting urea to a heat treatment at a temperature of about 160C.

7. A process for dyeing cotton, rayon or other vegetable fibers with wool or silk dyes, comprising chemically afllxing the wool or silk dye with the initial condensation products of formaldehyde with preliminarily heat-treated urea.

8. A process for dyeing cotton, rayon or other vegetable fibers with wool or silk dyes, comprising treating the fibrous material with the initial condensation products of formaldehyde with preliminarily heat-treated urea, then subjecting the resultant fibrous material to a heat treatment. and finally dyeing the heat-treated fibrous material with a wool or silk dye.

9. A process for dyeing cotton, rayon or other vegetable fibers with wool or silk dyes, comprising treating the fibrous material with the initial condensation products of formaldehyde with the mixture obtained by subjecting urea to a thermal treatment at a temperature of about 160 C.. thereafter subjecting the fibrous material to heat treatment, and then dyeing it with a wool or silk 10. A dyeing mixture for cellulosic materials comprising a wool or silk dye and the initial condensation products of formaldehyde with preliminarily heat-treated and partially thermally decomposed urea.

11. A colored cellulosic material wherein the wool or silk dye is chemically amxed with the initial condensation products of formaldehyde with preliminarily heat-treated and partially thermally decomposed urea.

12. A process for dyeing cotton, rayon or other fibrous materials with a wool or silk dye comprising afiixing the dye used by a heat treatment of the fibrous material in presence of a formaldehyde compound of heat-treated and partially thermally decomposed urea.

13. A colored fibrous material wherein the coloring matter is mechanically aflixed with a heat-treated formaldehyde compound of heattreated urea.

14. A colored fibrous cellulosic material wherein a wool or silk dye is chemically affixed with a heat-treated formaldehyde compound of heattreated urea.

GUSTAVE A. WIDMER. EDWARD W. PIERCE.