US2311080A

US2311080A - Textile treatment

Info

Publication number: US2311080A
Application number: US364886A
Authority: US
Inventors: Paul S Pinkney
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1940-11-08
Filing date: 1940-11-08
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

from such fabrics.

Patented Feb. 16, 1943 Paul S. Pinkney, Wilmington, Del., assignor to E. I. du Pont do Nemours & Company, Wilmington,Del., a corporation of Delaware .No Drawing. Application November 8, "1940,

. Serial N0. 364,886

8 Claims.

This invention relates to the treatment; with formaldehyde of textile materials which are reactive thereto. More particularly, it relates to a process for increasing the uniformity of reaction between formaldehydeand a textile material.

The term textile material is intended to include filamentaflbers, staple or yarns, whether in the finished stage or at someinte'rmediate stage in the production thereof.- The term also includes fabrics, whether knitted, woven. or

felted, as well as, garments or other articles made It has long been known to react textile materials with formaldehyde. Such reaction has been carried out for thepurpose of increasing the strength of textiles or to improve their resilience, crease resistance, crush resistance, crimp retention, resistance to shrinking, and to reduce the dry and ,wet elongation and the extent to which such materials are swelled by water.

Many of thesepreviously known processes have been unsuccessful due to the non-uniformity of \treatment or the embrittlement of the textile.

Processes used heretofore for treating textile materials with formaldehyde have involved treating the impregnated textile material in a hot-air chamber or on a drying cylinder. drying cylinders is applicable only to flat fabrics which are not too'thick for efficient heating.

Heating in a hot-air chamber is not satisfactory for yarn, rope, or staple, or for garments, because uniformity of treatment cannot be obtained unless heating is continued until all parts of the textile material have reacted to a maximum extent with the formaldehyde. This leads to extreme brittleness.

difficult to obtain uniformity of treatment due to the more marked effect of unevenness in the extent to which formaldehyde is lost by evaporation from the various portionsofthe textile material. When the heating period is reduced,

the less exposed portions of the textile material are likely to be markedly undertreatedi It is, therefore, an object of the present invention to provide a process for reacting a textile materia1 with formaldehyde with great uniformity and without objectionable embtrittlement.

It is another object of the present invention to provide a process for uniformly reacting a textile material with the minimum quantity of formaldehyde to accomplish the desired effect.

Treating on Other objects of the invention will appear hereinafter. e

The objects of'this invention may be accomplished, in general, by impregnating a formaldehyde-reactive textile material with the desired quantity of an aqueous solution of formaldehyde together with an acid-reacting catalyst, drying the impregnated material and heating the same to the desired reaction temperature by immersirig the same in a hot, substantially anhydrous liquid which is substantially inert to water; i. e., which is not hydrolyzable.

The following examples illu'strate in great detall, the preferred methods of carrying out the process of this invention. It is to be understood, however, that the present invention is not limited to the specific details set forth therein,

1 EXAMPLE I Skeins of l50-denier, IO-filament, 2.8-turns per inch twist, bright unfinished viscose rayon yarn are impregnated with a water solution containing the amounts of formaldehyde and ammo'nium chloride indicated in Table I. The saturated skeins are centrifuged to remove excess solution, and immersed in boiling benzene for 1 hour. Water is distilled with the benzene during this heating step so that the yarn is, in effect, dried and then heated under substantially anhydrous conditions. The skeins are centrifuged, dried at room temperature, treated with a 1% aqueous ammonium hydroxide solution at 50 C. for 5 minutes, rinsed, and dried. Results I When lower concentra- Y tions of formaldehyde are usedfit is even more of this treatment are summarized in Table I:

Table I i I s e mmoncrease onga on Formal Crease in wet nirnn dehyde chloride angle strength Wet Dry 7 Per cent Per cent Degrm Percent Percent Percent Control.- None None C 4.0.12 99 lii""8 7 When the treated yarns are dyed with du Pont Pontamine" Sky Blue 632! (Rowe Color Index No. 518), a direct cotton dye, it is very apparent that the yarn ineach sk'ein is uniformly modifled throughout the skein. The affinity of viscose rayon for direct cotton dyes is lowered by treatment with formaldehyde to an extent which varies with the severity of the treatment. Thus, when part of a skein is more heavily treated with formaldehyde than the rest of theskein, it is dyed much lighter than the rest of the skein. Unevenness of this nature is very apparent when a skein of viscose rayon yarn is dyed after being treated with an aqueous solution containing 8% of formaldehyde and 0.25% of ammonium chloride, centrifuged, dried at 65-70 C. for 2 hours, an baked at 150 C. for 3' minutes.

Crease angles of yarn of this type are determined by winding single threads over a doubleedged lmife blade under a tension of 50 grams, removing the tension after 15 minutes, cutting the thread along one edge of the knife, and determining the average angle of crease of about 10 of the resulting short lengths of thread after a relaxation period of 10 minutes. An increase in crease angle indicates improved resilience.

Exmu: II

A skein of viscose rayon. yam like that treated in Example I is impregnated with a water solution containing 3% of formaldehyde and 0.4% of ammonium chloride, centrifuged, dried at room temperature, immersed in xylene at 138' C. for 2 minutes, rinsed with methanol treated for '3 Exlmru III A skein of viscose rayon yam like that treated in Example I is impregnated with a water solution containing 3% of formaldehyde and 0.4% of ammonium chloride, centrifuged, and dried at room temperature. It is immersed for 2 minutes in bis(methoxyethoxyethyl) ether at a temperature of 138 C. The treated yarn shows uniformly improved resilience. Butoxyethoxyethyl acetate can be used as the liquid heating medium with the same advantageous results. Y

EXAMPLE IV There are described in U. S. application Serial No. 318,326, filed February 10, 1940, by William D. Nicoll, new high tenacity crimped regenerated cellulose filaments and fibers and a process for producing them which comprises the steps of spinning filaments from a viscose solution into a single coagulating and regenerating bath and relaxing the filaments, free from tension, in an aqueous liquid, said steps being carried out in accordance with certain critical relationship factors listed in the application. ,A skein of yarn prepared by this process is impregnated with a water solution containing 3% of formaldehyde and 0.4% of ammonium chloride, centrifuged, and dried at room temperature. It is immersed for 1 minute in xylene heated to 138 C. and washed according to the procedure used in Example 11. The crease angle of the yarn is increased by this treatment from 86that of the untreated yarnto 133";

its wet, strength is increased 14%; and its elongation, both'dry and wet, is lowered. The treated yarn shows uniformly improved crimp retentivity and resistance to swelling by water. Non-uniform modification of a skein of this yarn treated similarly except that it is heated in air is quite apparent when the yarn is dyed.

EXAMPLE V High tenacity viscose rayon yam prepared by the process described in U. S. Patents Nos. 2,083,252 and 2,133,714 is wound on a bobbin, impregnated with a water solution containing 5% of formaldehyde and 0.5% of ammonium chloride, centriffi'ged, and dried at room temperature. It is immersed for 30 seconds in xylene, rinsed with benzene, dried,.washed with a warm 1% rinsed, and dried. The improved resilience of the 15 yarn treated in this manner is shown by the rise in crease angle from l13-that of the untreated yarnto 133. The treated yarn shows lowered elongation and improved resistance to swelling by water. Yarn of this type treated similarly except that it is heated in air is markedly less uniformly modified.

ExAurtr: VI

Skeins of the new crimped viscose rayon yarn 5 (2,500-denier, 100-filament, 2-turns per inch 'twist) described and claimed in U. S. application Serial No. 180,976, filed December 21, 1937, by William Hale Charch and William Frederick Underwood, are treated according to theprocedure of Example I. This new yarn is produced as described and claimed in the above application by the extrusion of viscose into a; coagulating bath having a rapid coagulating action and a slow, or no, regenerating action with a velocity of extru- $1021 at least 4 times the velocity of draw-off. The streams of viscose issuing from the spinneret into the coagulating bath under the aforementioned conditions spontaneously assume a finely crimped form which persists as a permanent structural characteristic in the filaments. The resulting yarn is composed of substantially non-crenulated filaments having an inherent and'substantially permanent crimp, the crimps in the several filamerits of the yarn being out of phase with each other. The filaments exhibit substantially no orientation in the direction of the fiber axis.

Results of the formaldehyde treatment are summarized in Table II. The figures given in the table to represent the changes in properties eflectedby the treatment are, of course, with reference to untreated yarns.

Table II De- De- Decrease crease Form- Ammo- Increase in sponin aldenium Crease crease in taneous secondhyde chloride angle in wet elongaextenary stren th tion 'sion swellwhen ing wet C o n Per cent Per cent Degrees Per cent Per cent Per cent Per can! trol None None 66 A 13 0. 4 180 135 100 80 B. 8 0. 129 144 37 63 74 C. 4 0.12 76 47 42 46 49 Crease angle measurements on the yarn are made in much the same manner as described in Example I except that the length of yarn to be tested is hung from a double-edged knife with a 500-gram weight for 2 minutes, wound around the blade, and out along one edge after 10 minutes. llhe angles are let relax for 10 minutes before measuring.

Seco n dary swelling is measured by wetting weighedskeins of untreated and treated yarns aqueous ammonium hydroxide solution,

with water, centrifuging them together, and weighing each in a closed container to determine the amountof water retained. The untreated yarn usually retains a quantity of water approximately equal to the weight of the yarn. The secondary swellingof treated yarn is expressed as per cent relative to that of theuntre'ated'yam. This untreated yam extends spontaneously when wet with water until it is '40%-50% longer than when dry. v

The excellent uniformity of treatment-by the process of the present invention is apparent upon examination of skeins of the treated yarn after dyeing with a direct cotton dye, On the other hand the same yarn, when treated with a water solution containing 8% of formaldehyde and 025% of ammonium chloride, centrifuged, dried at 6575 C. for 2 hours, baked at 153 C. for 3 minutes in an oven, and dyed with-a direct cotton dye, is colored very unevenly. This unevenness indicates "a very non-uniform treatment.

EXAMPLE VII A skein of crimped viscose rayon yam like that treated in Example VI is impregnated with a water solution containing 3% of formaldehyde and 0.4% of ammonium chloride, centrifuged, and immersed for 10 minutes in xylene heated to 138 C. The yarn is improved uniformly by this treatment in resilience and wet strength.

Exsuru: VIII Skeins of crimped viscose yam like that treated in Example VI are impregnated with water solutions containing 0.4% of ammonium chloride and the amounts of formaldehyde indicated in Table III, centrifuged, dried at-room temperature, immersed for the indicated period of time in xylene heated to 138 C., and washed by the procedure of Example II. Results of the treatments are summarized in Table III; Dyeing tests show the treatments are all quite uniform. When bis(ethoxyethyl) ether is used instead of xylene, the results are equally favorable. This solvent has the added advantage of being miscible with water and, therefore, readily removable from the fabric.

Table III I Tim r In Qe Formal- Crease crease dehyde m" angle i inelon- 2:53;, swelling Per can) Minutes Degrees Per cent Per cent Per cent None '66 1 l 70 13 32 $3 1 2 72 15 33 44 1 -87 35 as 62 2 2 105 92 58' 66 2 5 108 72 53 80 3 1 113 81 '43 at 3 2 m 110 is 77 3 5 156 T5 61 l 89 5 l 166 84 53 s2 5 2 180 55 -58 as 2 180 0 63 85 Exssnmn IX Gel staple fibers prepared by the process of U. 8. application Serial No. 180,976, referred to in Example VI are impregnated with a water solution containing 2% of formaldehyde and 0.4% of ammonium chloride, centrifuged, and dried at room temperature. They are immersed for 5 minutes in mineral oil heated to 145 C. and then thoroughly washed with soap to remove the oil. The treated fibers show improved resilience and resistance to swelling in water. Dyeing tests show the treatment is uniform throughout. Fibers in staple form are particularly dimcult to heat uni formly in air.

' ExAm'LnX A rope of yarn of the type treated in Example VI .15 impregnated with a water solution containing 2%.of formaldehyde and 0.2%v of ammonium chloride, centrifuged, and dried at room thick to be heated uniform-1y throughout in a temperature. It is immersed for 5 minutes in triethanolamine heated to 150 C. and then"- washed with water. The treated fibers show uniformly improved resilience and resistance to swelling in water. Rope of this nature is too perature. They are immersed for 1 minute in Wood's metal heatedto 138 C., washed with an alkaline soap solution, rinsed, and dried. Both treated skeins show uniformly improved resilience and resistance to swelling in water.

Exsurnn XII Transparent velvet having a viscose rayon pile and silk backing is impregnated with a water solution containing 13% of formaldehyde and 0.4% of ammonium chloride, centrifuged, and placed in boiling benzene for 1 hour. It is then dried, 85

rinsed with warm dilute ammonium hydroxide solution, and soaped for 1 minute at 70 C. with j Exsurns XIII- Samples-of transparent velvet having a viscose rayon pile and silk backing are impregnated with a water solution containing 0.4% of ammonium chloride and 2% and 5% of formaldehyde, re-

spectively, centrifuged, and dried at room tem- ,perature. They are immersed for 1 minute in and water, heated in dilute ammonium hydroxide xylene heated to 138 C., rinsed with methanol solution at 10C. for 3 minutes, and then in an alkaline soap solution at 70' .C. for 3' minutes.

and rinsed. Both samples show improved resilience. Exsurnr XIV Viscose rayon yarn spun from viscose containing casein as described in British Patent No. 501,531 is impregnated with a water solution contairiina 3% of formaldehyde and 0.4 of ammonium chloride. centrifuged. and dried at room temperature. It is immersed for 1 minute in xylene heated to 138 'C. and then washed. The treated varn shows uniform y improved resilience and wet strength and lowered elongation.

tetrachlorooctane,

dichloride,

As above set forth, if any formaldehydereactive textile material is impregnated with aqueous formaldehyde and an acid-reacting catalyst, dried and then heated-byimmersion in a hot substantially anhydrous liquid which 5 is substantially inert to water under the conditions prevailing during the heating step, an improved and-morev uniformly treated product will be obtained. a

As a formaldehyde-reactive textile material, the present invention contemplates the treatment of filaments, yarns, fabrics and the like. comprising regenerated cellulose, regenerated, protein materials, and low substituted cellulose esters and ethers; i. e., cellulose esters and ethers having at least one unsubstituted hydrox'yl group.

The present invention is operative in the treatment of all textile materials which are at all reactive to formaldehyde. In the treatment of such textiles asare less reactive than those specifically referred to above, the treating conditions will,'of course, be more drastic.

The term textile material includes fibers in the form of loose staple, yam, fabric, or finished article and filaments in the form of yarn, fabric,

or finished article. The fabrics may beknitted',-\

woven, or felted. They may be special'types of fabric such as pile fabrics or crepe. Viscose rayon fibers may be treated in the gel state either as staple, rope, or yarn.

The term "acid-reacting catalyst is intended to include water soluble substances which are acid in reaction, or capable of becoming acid under the conditions of the treatment, or capable of. liberating an acid under the conditions of the treatment. Examples are organic 'carboxylic or sulfonic acids such as oxalic acid,

tartaric acid, and benzenesulfonic acid, acid salts of organic acids such as sodium acid 40 tartrate and potassium tetroxalate, mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid. acid salts of mineral acids 7 such as sodium bisulfate and dihydrogen sodium phosphate, and salts of strong acids with'weak bases which dissociate in water solution to give an acid reaction such as ammonium thiccyanate, anmionium chloride, "ammonium bromide, ammonium iodide, ammonium sulfate, hydroxvlamine hydrochloride, ferric chloride, calcium chloride, aluminum chloride, 'etc. The catalyst chosen in any particular case will be the one which is sui'llcientlypowerful to effect" the degree of-chemfcal reaction desired between the textile material and the formaldehyde. Because of its cheapness' and effectiveness, ammonium chloride lathe catalyst which is preferred in the exercise of this invention.

As liquids suitable for use as heating media in the prgaess of this invention, there may be usedany substantially anhydrous liquid boiling above C. and preferably above C. which "is substantially inert to water under the conditions prevailing during the heating step. :Exarnpies are hydrocarbons such as benzene, toluene, 55

mlene, kerosene, mineral oil, high boiling benzine, triisobutylene, etc., esters such as. butyl acetate, tricr'esyl phosphate, dime-thyl phthalate, Cellosolve? and Carbitol esters, butyl V borate, etc., alcohols, such as glycerol, ethylene 7o glycol, butanols, octanols, etc., halides such as tetrachloroethylene, chlorobenzene, bromobenzene, tribromoethane, amylene chloronaphthalene, chlorotoluene,

dicblorobenzenes, etc., hydroxy ethers suchas 7 Cellosolves and Carbitols, ethers such as diisobutyl ether, bis(methoxyethoxyethyl) ether, and dioxane, amines such as monoethanolamine, diethanolamine, triethanolamine, dimethylaniline, etc., and low melting metals or alloys such as Woods metal, Rose metal, and mercury. The organic liquids used may be aliphatic 'oraromatic, saturated or unsaturated. Of -course, esters and ethers which are solvents forcellulose esters and ethers cannot be used as heating media in treating textile materials composed of the latter substances. In any case the liquid used should preferably be easily removed from the textile material, stable toward heat, inert toward water, non-toxic, and non-flammable. Bls(methoxye thoxyethyl) ether and bis(ethoxyethyl) ether are preferred heating liquids in carrying out the'present invention.

The formaldehyde treating solution maycontaln desiredmodifying agents which will improve the resulting product, as long .as the modifying agent does not interfere with the reaction between the formaldehyde and the textile material. For example, long chain agents such as glycerol monostearate or sulfonated castor oil may be added to the formaldehyde solution to improve hand and feel of the textile material. However, when such a long chain agent is used and the liquid heating medium used is a solvent for it, it is preferable to saturate the liquid heating medium with-the long chain agent so that the agent will be retained by the textile material and not dissolved out by the heating medium. r

" The concentration of formaldehyde to be used in the treating solution varies, of course, with the material under treatment, the nature and concentration of the catalyst, the nature and concentration of modifying agents, the conditions of drying and heating, and the effect desired. For example, for creaseprooflng viscose rayon a higher formaldehyde concentration is required than for shrinkprooflng the material, other conditions remaining the same. Generally, when the drying and heating conditions are more severe, that is, when higher temperatures and longer times are employed, less formaldehyde is required. Thus, if the impregnated ma: terial is dried at 100 C. rather than at room temperature, less formaldehyde will be required to give the same final effect. Generally, -to obtain comparable. effects, less formaldehyde is required when a more strongly acidic catalyst is employed or when a catalyst is used in higher concentrations, than when a more weakly acidic catalyst is employed or when a catalyst is used in lowerconcentrations. Usually, a concentration of formaldehyde of at least 1% is required to obtain a-noticeable effect on cellulosic. materials. The upper limit is the concentration at which the particular textile material being treated is made too weak or too brittle for use. As a general rule, the formaldehyde concentration should not exceed 20%. With these facts in mind, one skilled in the art can readily determine the concentration of formaldehyde which will give optimum results under a given set of other conditions.

The catalyst concentration may vary from as low as 0.05% or lower to as high as 1% or higher depending on the potential acidity of the catalyst,

the nature of the textile material under treatment the concentration of formaldehyde employed, the nature and concentration of modifying agents, the drying and heating conditions,

and then squeezed temperature to 150 C. or higher.

and the effect desired. Other conditions remaining the same, an increase in the catalyst concentration or a change from a less to a more strongly acid catalyst results in a greater degree of modification of the textile material. Usually, the selection of the nature and concentration of the catalyst is a matterof balancing catalyst efilciency against tendering which results from the use of acidic materials on many textile materials, particularly celiulosic materials. By reference to the above examples and the following description one skilled in proper catalyst and concentrationto bring about the desired result- The treating solution may be applied to the textile material in any of several ways. Staple fibers may be dipped in the solution and squeezed or centrifuged to remove may be passed continuously through the solution or it maybe dipped in skein form in the solution or centrifuged to remove excess solution. Flat fabrics may be passed through the solution or the solution may be applied from rolls or by spraying and the excess may be removed by squeezing between rolls orby vacuum extracting. Articles, as of clothing, may be dipped in the solution or sprayed. Fabrics or articles of clothing may be treated locally by spraying.

The formaldehyde and catalyst may also be applied in other ways. For example, the textile material may be wet with a solution of the catalyst and then exposed to vapors of formaldehyde, or it may be Wet with formaldehyde solution and then exposed to a gaseous catalyst such as hydrochloric acid.

After impregnation with the treating solution the textile material is preferably dried to a water content of about or less before it is subjected to the final heat treatment. This may be carried out many of several ways. It maybe dried in air or in a heated inert liquid such as a hydrocarbon or ether. If it is air dried, the temperature of drying may .range from room high temperatures in air must be carried out with care so that no part of the textile material is heated after it is dry. Uniformity is favored by vigorous circulation of air in the drying chamher and by use of temperatures below 100 C., and preferably below 50 C. The most uniform drying, particularly for staple, large skeins of yarn, and garments, is obtained by use of a hot the art can readily select the- Drying at 2,a11,oso

excess solution. Yarn material under treatment is'in a relatively loose condition so that air will circulate through it freely, air drying has an advantage over drying in a hot liquid in that the formaldehyde concentration required for a given degree of modification is much lower and the overall period during which the material is held at. the higher liquid temperature is shorter, so that the risk of tendering due to the effect of the acid reacting catalyst at high temperatures is less. At higher temperatures the liquid drying method is generally more rapid due to more eflicient heat'transfer between the moisture and the heating medium. If, for example, a liquid such as molten metal is used at a temperature in the range of from 200-250. C. or higher, drying may oe complete in a fraction of a second. In general, with other conditions remaining constant, an increase in the drying temperature leads to a greater degree of modification of the textile material.

In orderto bring about areaction between formaldehyde and the textile material within a reasonable time, it is necessary to heat the impregnated and driedmaterial. In this process the heating step is carried out by immersing the textile material in a hot liquid of the nature disclosed above. The temperature of the liquid may be as low as 'l0 C. or lower, althougha much longer heating period is required at such low temperatures. As already pointed out, if a heating temperature below 100 C. is used, that temperature should be the boiling point of the liquid so that water formed by the reaction will be removed emciently. The temperature of the liquid may range as high as 200 C. or even higher. However, it should be emphasized that at such high temperatures the heating period modifying agent, thetemperature of drying, the

time of heating, the effect desired,and the nature of the textile material under treatment.

A It is common knowledge that some textile materials are more susceptible to damage by heat than are others and so require more careful treatment in any heating process. In general,

with other conditions remaining constant, an increase inthe temperature of the heating liquid leads-to a greater degree of modification of the textile material under treatment.

inert liquid in which water is preferably no more than slightly soluble. Liquid temperatures up to 250 C. or higher may be used. If a temperature below 100 C. is used, it .is usually necessary to boil the drying liquid in order to carry out-the water. Consequently, for drying at such temperatures liquids boiling below 100 C. are desirable. However, if they boil below about C. the rate of drying will generally be too low for practical purposes.

The time of drying depends, of course, on the drying method used. When the air drying method is used, the time required depends onthe temperature, circulation of air, and the relative thickness and looseness of the material under treatment. When the hot liquid drying method is used, the time required depends on the nature of the liquid and the temperature used and less on the construction of the material under treatment. In general, with temperatures below 100 C., the air drying method is more rapid and may require as short a time as 2 minutes. When the "Cline heat ng per od may be varied from as long as an hour or more at low temperatures, such as 70 -80 C. or lower, to a fraction of a second at higher temperatures. such as 200 C. .or higher. When the heating is to be carried 'on over a period of about a minute or longer it is advantageous to place the textile material in a perforated container which is lowered into the hot liquid bath and then lifted after the desired length of time. When yarn or fabric is to be heated at .a higher temperature {for a shorter period oftime, it is advantageous to pass the yarn or fabric continuously through the heating bath at a rate depending on the length of bath travel. With other conditions remaining constant, an increase in the heating period leads to a greater'degree of modification of the textile material under treatment.

From the above descriptions, it will be apparent that the drying step'and the heating step may be combined into one continuous step. The drying liquid may be used for the subsequent heat treatment. Thus, it is sometimes convenient to prolong the period of immersion in the drying liquid until the reaction between formaldehyde and the textile material has proceeded to the desired point.

After the heating step it is usually desirable to remove theheating liquid. This may be accomplished simply by evaporation of the liquid if the liquid is sufllciently volatile, benzene, for example. If the liquid is water soluble, triethanolamine, for example, it can be washed out with water. Water insoluble non-volatile materials may be displaced by a volatile or water soluble solvent or removed by soaping. It is usually desirable to neutralize any traces of acidic material which may be left in the yarn by washing with a solution of ammonium hydroxide or other mildly alkaline material. The treated material may then be finished inany desired manner such as by application of a softening agent or water repellent agent.

Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the present invention, it is to be under-' stood that the invention is not to be limited to the said details except as set forth in the followingclaimsw 1 I claim:

1. In a process for reacting a textile material with formaldehyde, the steps comprising-umpregnating said material \with an aqueous solution of formaldehyde, drying said impregnated material, and heating the same to reaction temperature by immersion in an inert heating liquid at a temperature of between 70 C. and 200 0., whereby said material isuniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented.

2. In a process for reacting a textile material with formaldehyde, the steps comprising im-' pregnating said material with an aqueous solution of formaldehyde and an acid reactingic'atheating liquid at a temperature of between 70 C. and 200 0., whereby said material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented.

4. In a process for reacting a regenerated cellulose textile material with formaldehyde, the steps comprising impregnating said material with an aqueous solution of formaldehyde and an acid reacting catalyst, drying said impregnated material, and heating the same to reaction temperature by immersion in an inert heating liquid at a temperature of between 70 C. and200 0., whereby said material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented.

5. In a process for reacting a regenerated cellulose textile material with formaldehyde, the steps. comprising impregnating said material with an aqueous solution of formaldehyde, dryingsaid impregnated material, and heating the same to reaction temperature by immersion in .a liquid comprising a hydrocarbon, whereby said material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented.

6. In a process for reacting a regenerated ceilulose textile material with formaldehyde, the

alyst, drying said impregnated material, and

heating the same to reaction temperature by immersion in an inert heating liquidat a temperature of between 70 C. and 200 (3., whereby said material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented. l

3. In a process for reacting a regenerated cellulose textile material with formaldehyde, the steps comprising impregnating said material with an aqueous solution of formaldehyde, drying said impregnated material, and heating the same to reaction temperature by immersion in an inert steps comprising impregnating said material with an aqueous solution of formaldehyde, dry

ing said impregnated material,and heating the same to re'action temperature by immersion in a liquid comprising xylene, whereby said material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented.

7. In a process for reacting a regenerated cel.-.

lulose textile material with formaldehyde, .the steps comprising impregnating said material with an aqueous solution of formaldehyde, drying said impregnated material, and heating the same to reaction temperature by immersion in a liquid comprising bis(ethoxyethyl) ether, wherebysaid material is uniformly reacted with the formaldehyde and objectionable embrittlement thereof is prevented. i

8. The process of decreasing the secondary swelling of substantially non-crenulated and non-oriented, permanently crimped, regenerated cellulose filaments which comprises impregnating a textile material composed of said filaments with an aqueous solution of formaldehyde, drying said impregnated material, and heating the same to reaction temperature by immersion in an inert heating liquid at a'temperature of between C. and 200 C.

PAUL 8. PM.