US2254001A - Textile process - Google Patents

Description

Patented Aug. 26, 1941 TEXTILE PROCESS Rollin F. Conaway, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware a. Drawing. Application November 14, 1938, Serial No. 240,428

9 Claims.

This invention relates to the treatment of textiles, particularly for the modification of the elastic and hydrophobic properties thereof and more particularly to the crease-proofing thereof.

The attention of textile chemists has, for many years, been directed to the surface modiflcation of textile materials to improve appearance, change the feel and render the textile material more resistant to the influences exerted on the textile material when in service, etc. A recent step is that of crease-proofing" textiles, i. e., rendering them resistant to creasing in service. One of the methods of so doing is to impregnate the textile with an aqueous solution of a urea-formaldehyde resin and bake the same in the presence of an acid catalyst. This process -has certain disadvantages, for example, the

fabric is perceptibly tendered on baking and the aqueous solution of the urea-formaldehyde resin is so unstable as to be unfit for use after standing only a few hours.

This invention has as an object the provision of an improved process for textile treatment. Another object is the provision of a process for crease-proofing textiles and particularly cellulosic textile materials. Another object is the provision of a process for crease-proofing textiles without substantial tendering of the same. Another object is the provision of a process for treating textiles to effect improvement in feel, aflinity for dyes, resistance to water and/or resistance to creasing. A further object is the provision of a process using impregnants stable on storage. A still further object is the provision of a process of rendering textiles resistant to creasing and at the same time waterrepellent. Other objects will appear hereinafter.

These objects are accomplished by the following invention wherein a cellulosic or textile material is impregnated with an aqueous solution of an alkyl and preferably a lower alkyl ether of a methylolurea, which solution may also contain dispersed therein a water-repellent, and baked to fix the agent (and water-repellent, if present) on the textile or cellulosic material.

The process of the present invention in its preferred modification involves the treatment of cellulosic textiles with an aqueous solution of a water soluble alkyl ether of a methylolurea, with or without an acid catalyst, with or without preliminary drying of the impregnated fabric, followed by baking to the point of insolubilizing the impregnating agent. The following Exweight, exemplify the preparation of certain ofthese ethers and of their aqueous solutions, by reacting dimethylolurea with an alcohol in the presence of an acid catalyst or of a neutral dehydrating agent.

Example A Example B One hundred and five parts of dimethylolurea containing 18 per cent of water is heated at about 40 C. with 640 parts of methyl alcohol until a clear solution is obtained. One-half part of 5 Nhydrochloric acid is added to the solution with rapid agitation. After five minutes, the acid is neutralized with basic lead carbonate, the solution filtered, and. evaporated until crystallization occurs. Eighty parts of crystalline dimethyl ether of dimethylolurea is obtained which, after recrystallization, melts at 101 C. The diethyl ether of dimethylolurea may be prepared by a similar procedure in which the methyl alcohol is replaced with ethyl alcohol. The crude plate-like crystals, after recrystallization, melt at 123 C.

Aqueous solutions of these crystalline materials containing 2 to 40 per cent of the crystalline ethers are employed as impregnating agents for textiles. Such aqueous solutions are very stable and may be stored for months without appreciable change.

Example C One hundred and eighteen parts of dimethylolurea containing 18 per cent of water is heated with 100 parts of methyl alcohol at 50 C. with agitation for twenty minutes. One-half part of phthalic anhydrlde is added to the reaction mixture and the solution refluxed until all of the dimethylolurea dissolves which requires approximately twenty minutes. The resulting clear solution of the dimethylolurea methyl ether is neutralized with 0.2 N sodium hydroxide solution and diluted with water to the desired conamples, A, B, C, and D, wherein parts are by centration.

Example D A mixture of 100 parts oi. dimethylolurea. containing 20 per cent of water, 160 parts of ethyl alcohol, 100 parts of water, and 1 part of citric acid is heated with stirring at 60 C. for ten minutes. The solution is neutralized and filtered. The reaction product, which is essentially the monoethyl ether of dimethylolurea. is isolated in crystalline form by evaporation. of the solution. The resulting crystals are extremely soluble in water. Similar water soluble products can be prepared by replacing the ethyl alcohol in the above reaction mixture with isopropyl alcohol. I q

The procedure of preparing concentrated (approximately 60 per cent solids) solutions of the ethers and'diluting them with distilled water without isolating the crystalline product has been found to be the simplest and most satisfactory procedure. The neutral aqueous solutions are stable over a period of several months. Other acids such as citric, acetic, etc., can be employed in place of phthalic anhydride as the catalyst. Likewise, other alcohols such as propyl and ethyl alcohols can be employed in place of methyl alcohol.

In that modification of the invention wherein the textile is impregnated with a water repellent as well aswith a crease-proofing agent, the bath is prepared by emulsifying a water-repellent in the bath prepared as in the examples above. Where the water-repellent ingredient is a liquid or a low-melting solid, the emulsions are prepared by adding the liquid or molten waterrepelling agent to the aqueous solution of the methylolurea ethers containing an emulsifying agent. With the higher melting solids such as stearamide the solid water-repellent is dissolved in the minimum amount of an organic solvent such as ethyl alcohol, acetone, ethyl acetate, etc., and the resulting solution of the water-repelling agent added to the aqueous solution of the ether of the methylolurea in the presence of a small amount of an emulsifying agent, such as sodium dodecylsulfate or the sodium salts of branched chain monocarboxylic acids containing 7 and 8 carbon atoms which are obtained by the oxidation of the higher alcohols resulting from the methanol synthesis, the solutions being stirred vigorously during the formation of the emulsion in order to obtain uniform dispersions. The concentration of the emulsifying agent varies from 0.1 to on the basis of the total volume of the solution.

The preferred procedure involved in treating textiles consists in (1) wetting the fabricsuniformly with water, (2) impregnating the wet fabrics with a solution of an alkyl ether of a methylolurea by nipping several times between rubber rolls, (3) baking the impregnated fabrics for approximately five minutes at about 170 to about 175 C., and (4) laundering in a hot soap solution, rinsing thoroughly in water, and ironing. In crease-proofing processes employing the ordinary urea-formaldehyde condensation products,'the impregnated fabrics must be dried at essentially room temperatures prior to baking, but this step is not necessary when the methylolurea ethers are employed as the crease-proofing agents.

The more detailed practice of the invention is illustrated by the following examples, wherein parts given are by weight. Examples I to VII illustrate crease-proofing, Examples VIII to XVII illustrate water-proofing also. There are of aaeaooi course many forms of the invention other than these specific embodiments.

Example I Water-wet muslin fabric is impregnated with a 40 per cent neutral aqueous solution of the dirnethyl ether of dimethylolurea. The fabric is air-dried, baked for six minutes at C., and

laundered. The resulting fabric is resistant to creasing.

, Example II Wet muslin fabric is impregnated uniformly with a 30 per cent aqueous solution of the dimethyl ether of dimethylolurea. and baked for six minutes at 170 C. The resulting laundered fabric is as crease-resistant as the fabric in Example I in which the impregnated material is dried prior to baking.

Example III Muslin fabric is impregnated with a 6 per cent aqueous solution of the dimethyl ether of dimethylolurea containing 0.5 per cent of ammonium chloride based on the impregnating agent. The resulting fabric is air-dried, baked for three minutes at. 170 C., and laundered. The resulting fabric is very resistant to creasing.

Example IV Web cotton voile fabric is impregnated with 20 per cent neutral aqueous solutions of the diethyl ether of dimethylolurea. The resulting fabric is air-dried, baked for five minutes at 170 C., and laundered. It is resistant to creasing.

Example V Wet cotton voile fabric is impregnated with a 10% aqueous solution of the monoisopropyl ether of dimethylolurea containing 0.2% citric acid based on the impregnating agent. The resulting fabric is air-dried, baked for 3 minutes at C. and laundered. The resulting fabric is very resistant to creasing.

Example VI Muslin fabric is impregnated with a neutral solution of a mixture of ethers containing 50 per cent of a 20 per cent solution of the dimethyl ether of dimethylolurea and 50 per cent of a 20 per cent solution of the diethyl ether of dimethylolurea. ,The resulting impregnated fabric is baked at 170 C. for five minutes and laundered. Fabric treated in this manner possesses good resistance to creasing even after repeated laundaring.

Example VII Samples of viscose rayon fabrics and yarn are impregnated with 35 per cent solution of the dimethyl ether of dimethylolurea. The impregnated materials are baked at 170 C. for five minutes and laundered. These materials possess excellent resistance to creasing. 4

Example VIII Example IX Cellulose acetate fabric is impregnated with a 40 per cent solution of a dimethyl' ether of dimethy1olurea.- The impregnated fabric is dried.

baked at 150 C. for six minutes, and laundered.

Example X Muslin fabric is impregnated with an aqueous I emulsion of parts of stearyl alcohol in a solution containing parts of dimethyl ether of dimethylolurea, 12 parts of acetone, 1 part of sodium dodecylsulfate and 57 parts of water. The

impregnated fabric is dried. baked for 4 minutes at 170 C., and laundered. The resulting fabric is repellent to water and resistant to creasing.

Example XI Muslin fabric is impregnated with an emulsion of 6 parts of stearyl alcohol in a solution containing 16 parts of the dimethyl ether of dimethylolurea, 0.7 part of sodium salts of mono- Example XV Cotton voile fabric is treated with an emulsion of 12 parts of lauryl alcohol in a solution consisting of 10 parts of the dimethyl ether of dimethylolurea, 8 parts of the dlethyl ether of dimethylolurea, 0.5 part of ammonium dihydrogen phosphate and 69 parts of water. The impregnated fabric is baked for 6 minutes at 160 C. and laundered. It is crease-resistant and waterrepellent.

Example XVI Cotton broadcloth fabric is impregnated with an emulsion of 8 parts of stearylamine in a solution consisting of parts of the dimethyl ether of dimethylolurea, 1 part of sodium salts of .monocarboxyiic branchedchain acids containing 6-8 carbon atoms and 66 parts of water. The impregnated fabric is baked at 170 C. for 5 minutes and laundered. It is crease-resistant and water-repellent.

Example XVII Muslin fabric is treated with an emulsion of 10. parts of dodecylamine in a solution containing 10 parts of the dimethyl ether of dimethylolurea,

' 1 part of sodium dodecylsulfate, 1 part of amcarboxylic branched chain acids containing 6-8 carbon atoms, 0.3 part of ammonium chloride .and 77 parts of water. The wet impregnated fabric is baked for 8 minutes at 170 C. and laundered. Ten partsof dodecyl alcohol may be employed in place of the 6 parts of stearyl alcohol used above.

Example XII Example XIII Muslin fabric is impregnated with an emulsion of 6 parts of stearamide in a solution consisting of 16 parts of dimethyl ether of dlmethylolurea, 14 parts of butyl alcohol, 1 part of sodium salts of monocarboxylic branched chain acids containing 6-8 carbon atoms, 1 part of citricacid and 62 parts of water. The impregnated fabric is air-dried, baked for 4 minutes at 160 C., and laundered. Ten parts of lauramide may be employed in place of the 8 parts of stearamide.

Example XIV Muslin fabric is impregnated with an emulsion of 8 parts of stearamide in a solution consisting of 16 parts of the diisopropyl ether of dimethylolurea, 25 parts of isopropyl alcohol. 0.7 parts of sodium dodecylsulfate, 0.3 part of ammonium chloride and 50 parts of water. The impregnated fabric is dried at room temperature, baked for 4 minutes at 150 C., and laundered. The

resulting treated fabric is resistant to creasing and repellent to water.

monium chloride and 88 parts of water. impregnated fabric is dried at room temperature, baked at 170 C. for 4 minutes, and laundered. The resulting fabrics are resistant to' creasing and repellent to water.

This invention is generic to the treatment of cellulosic and textile materials with alkyl ethers of methylolureas. The treatment of cellulosic materials with the lower alkyl ethers of methylolureas and preferably dimethylolurea is a preferred modification because of the crease-proofing eil'ect on textiles. The water-soluble ethers of dimethylolurea such as the dimethyl and diethyl ethers are much more eflicient as creaseproofing agents than the alcohol-soluble derivatives such as the dibutyl ethers and for this reason are preferred thereto. Mixed ethers containing a lower alkyl group,- e. g., methyl ethyl dimethylolurea may also be used. The higher alkyl ethers of the methylolureas and particularly of monomethylolurea are of advantage not so much from the standpoint of crease-proofing as from the standpoint of water-proofing and improving the feed of the fabric. etc. The alkyl methylol ethers canbe produced by a number of methods and may be employed in this invention either by preparing aqueous solutions of the crystalline ethers or by diluting the original reaction mixtures with water to the desired concentration. The materials may beapplied either in the form of an aqueous solution or an aqueous alcohol solution, or an emulsion by any known process which impregnates uniformly the .individual fibers of the fabric or yarns. A method which removes excess impregnating solution from the exterior of the fibers, e. g. by nipping between tightly-set is preferable.

The concentration of the impregnating solution varies depending on the degree of creaseresistance desired. Thus for maximum effect 20%-30% or even higher may be used. For :medium results 6% to 10% is usually satisfactory, but a perceptible degree of creaseresistance, useful in some cases, may be obtained at concentrations as low as 2%. The preferable concentrations are between 5 and 30% of the urea ether but in cases where only a slight degree of creaserubber rolls or centrifuging,

acetic, succinic, malic, and tartaric acids and ammonium salts of these acids and of inorganic acids are preferred.

The invention is likewise generic to the use in combination with the methylol ethers of long chain organic compoundsas water-repellent materials. Waxes such as paraffin wax, Asiatic wax, Carnauba wax, beeswaxand spermaceti may be employed. Best water-proofing results are obtained with long chain organic compounds in-,- soluble in water and dilute alkali and. containing an open chain of at least eight carbon atoms attached to a polar group containing a polyvalent, negative, inorganic, element of the first series of the Periodic System attached to hydrogen. Thus long chain amines, amides, and alcohols, are effective. Specific water-repellents include octyl, decyl, dodecyl, and octadecyl alcohols, ethers, and amines, and the amides of caprylic, lauric, palmitic and stearic acids.

The aqueous emulsions can be prepared by a number of methods, such as adding the longchain water-repellent compound in solution or in the molten state to the aqueous solution of the methylolurea or by adding the aqueous solution to the long-chain alcohol, amide, or amine in the presence of an emulsifying agent. In cases where the suitable alcohols, amides, and amines are solids at room temperature, but possess relatively low melting points (30-60 C.), it is possible to add the solid material to a warm aqueous solution of the methylol ethers in the presence of an emulsifying agent. It is essential to have rapid agitation during the preparation of the emulsionin order to obtain uniform, stable systems. The agitation can be obtained either by rapid mechanical stirring or by special mechanical homogenizers. If an acid catalyst is employed such as citric acid or ammonium chloride, it is best to add the acidic material to the emulsion prior to impregnating the fabrics rather than during the preparation of the emulsion.

The baking treatment can be carried out in any customary manner which subjects the fabric to a relatively high temperature for a short time, such as ovens, air chambers, heated rolls, etc. Ironing may be used if desired. The temperature of baking should be no higher than necessary to obtain the desired reaction rate but best results are obtained at temperatures between about 140 and about 175 C. Temperatures even somewhat lower than 140 C. may be used provided the time of baking is suitably adjusted. Temperatures over 200 C. should be avoided. The time of baking varies with the type of fabric from about two minutes at 170 C. for thin, light-weight, materials to six to eight minutes at 170 C. for the thick, heavy, fabrics. For cellulose acetate fabrics a temperature around 150 is preferable. In any case, the baking treatment is continued until the treating agent is lnsolubilized and is then promptly discontinued. The impregnant at this point is still an etherified methylolurea, i. e. the cloth is impregnated with a resin containing an etherifled methyiolurea. The final laundering operation can be carried out in a variety of methods, but any commercial process involving thorough washing in hot water, rinsing, and ironing. is satisfactory.

While the crease-proofing is most effective with cellulosic materials, e. g. textile materials having a cellulosic nucleus such as cotton, viscose rayon, linen acetate rayon, cuprammonium rayon, rayon and non-textile materials such as paper and regenerated cellulose foil, etc., the process is applicable to organic textile materials such as wool and slik, but with less outstanding results. The water-proofing effect is also more effective with cellulosic fabrics. It is not possible to give at the present time a theoretical interpretation of the results obtained by the process of the present invention. With regard to the water-proofing phase of this invention, the permanency of the effects obtained in this invention with the polar long chain compound is believed to be due to the fact that the polar water-repellent agent, namely, the long-chain amide, amine, or alcohol, enters into chemical combination with the ethers of'dimethylolurea which are the crease-proofing agents. The eifects obtained in this invention are different from those obtained by processes de. scribed in the prior art in which a waiter paramn is used as the water-proofing agent in that the fabrics treated by the latter processes are not permanent to laundering or dry cleaning.

The principal uses of the invention are in modifying the elastic and/or hydrophobic properties of textile materials and particularly of cellulose or regenerated cellulose materials and fabrics. Among the most important uses is in the production of crease-resistant textiles, other uses such as setting the crimp in crinkled yarns and insolubilizing cellulose materials, particularly films and fibers, e. g. rendering cellulose insoluble in cuprammonium, caustic, etc. and rendering cellulose acetate insoluble in organic solvents are also of interest. The invention is also of importance in modifying the dyeing, swelling, and shrinking characteristics of cellulose materials. The invention can also be applied to cellulose derivatives such as the esters and ethers to modify the above properties.

The most successful commercial methods heretofore proposed for modifying the crease-resistant properties of cellulose fabrics are based on the use of the condensation products of. urea with formaldehyde, either in the monomeric form such as dimethylolurea or resinous products such as the water-soluble urea-formaldehyde resins. The advantages of the watersoluble ethers of dimethylolurea over the above products now employed are manifold and important. The principal advantages are (1) the crystalline ethers and their neutral aqueous solutions are infinitely more stable to storage (a neutral aqueous solution (20% solids) of soluble urea-formaldehyde resin precipitates on standing only a few' hours at room temperature while a neutral 20% solution of the dimethyl ether of dimethylolurea is stable for 3 months or more under similar conditions). The dry crystalline ethers appear to be stable almost indefinitely; (2) tendering of the fabric is greatly reduced; (3) preliminary drying of the fabrics prior to baking may be omitted; (4) the crease-proofing effect obtained, in comparison to products creaseproofed with the regular urea-formaldehyde although Y condensation products, is more pronounced and more resistant to repeated laundering; and operations involved are simpler in that the desired combined effects are obtained by a single impregnation.

One of the greatest disadvantages of the present commercial crease-proofing processes is the instability of the crease-proofing agents. Some of these agents, particularly the water-soluble resinous urea-formaldehyde products, are stable for only a few hours whereas the crystalline ethers of dimethylolurea and their neutral aqueous solutions are stable to storage for many months at room temperature. In the process employing the water-soluble urea-formaldehyde condensation products, the fabrics are tendered (weakened) to a marked degree during the baking treatment. The ethers of dimethylolurea, for some unexplained reason, are insolubilized with only a scarcely measurable tendering of the fabric. One of the most surprising advantages of the dimethylolurea. ethers as crease-proofing agents is that the water-wet impregnated fabrics can be baked directly without a preliminary drying treatment at low temperatures. This is a great advantage from a commercial viewpoint in that it eliminates a long costly drying operation from the processes now employed. The watersoluble, low molecular weight methylol ethers impregnate the fabrics more thoroughly and uniformly than do the resinous products employed in the present commercial processes, and therefore the resulting treated fabrics show a surprisingly greater uniformity and permanency of crease-proofing.

In the claims the term lower alkyl" represents an alkyl of one to three carbon atoms, e. g. methyl, ethyl and propyl. The term "0ellulose applied to a material represents a material havin a cellulosic nucleus unesterlfled and unetherified, e. g. cotton, linen, viscose, cuprammonlum or Chardonnet rayon, paper, regenerated cellulose in film form, and the like. The term cellulosic represents a material having a cellulose nucleus which may or may not be etherifled or esterifled. It therefore includes in addition to the "cellulose" textiles and materials, the

esters of cellulose, e. g. cellulose acetate and the ethers, e. g. ethyl cellulose.

The above description and examples are intended to be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

I claim:

1. Process of improving the crease-resistant properties of textile material which comprises impregnating a cellulose textile material with an aqueous solution of a lower alkyl ether oi a methylolurea, and baking the same.

2. Process of improving the crease-resistant properties of textile material which comprises impregnating a celulose textile material with an aqueous solution of a lower alkyl ether of di methylolurea and baking the same at a temperature not above 200 C.

3. Process of claim 2 wherein the baking is at -175" C.

4. A cellulose textile material of improved rease resistance impregnated with a resinous lower alkyl ether of dimethylolurea.

5. A cellulos c textile material of improved crease-resistance impregnated with a resinous lower alkyl ether of a methylolurea.

6. Process of improving the crease-resistant properties of textile materials which comprises impregnating a cellulose textile material with an aqueous solution of a methyl ether of dimethylolurea and baking the same at a temperature of BIO- C.

7. Process of improving the crease-resistant properties of textile materials which comprises impregnating a cellulose textile material with an aqueous solution of an ethyl ether of dimethylolurea and baking the sweat a temperature of 140-175 C.

8. A cellulose textile material of improved crease-resistance impregnated with a resinous methyl ether of dimethylolurea.

9. A cellulose textile material of improved crease-resistance impregnated with a resinous 45 ethyl ether of dimethylolurea.

ROILIN F. CONAWAY.

CERTIFICATE OF CORRECTION. Patent No. 2,25L oo1. August 26, 19in.

ROLLIN F. CONAWAY.

It is hereby certified that error appears in the printed specification oi the above numbered patent requiring correction as follows: Page 2, secnd column, line 50, for "web" read --wet--; page 5, second column, line 50, for the word "feed" read -feel--; page 14,; second column, 'line 15, for

"elik" read silk-'--; page 5, second column, line 16, claim 2, for "celulose" read ---cellulose--; and that the said Letters Patent'should be read with this correction therein. that the same may conform to the record of the case in the Patent Office. 1

Signed and sealed this 14th day of November, A. D. 191:1.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.