US3081513A

US3081513A - Process for the production of wash-and-wear characteristics in woven fabrics of regenerated cellulose

Info

Publication number: US3081513A
Application number: US7993A
Authority: US
Inventors: Marek Bruno Stefan Vladimir; Keiler Andre Michel
Original assignee: Societe de la Viscose Suisse SA
Current assignee: Viscosuisse SA
Priority date: 1959-02-19
Filing date: 1960-02-11
Publication date: 1963-03-19
Anticipated expiration: 1980-03-19
Also published as: NL248375A; BE587811A; CH187960A; CH362396A; GB892128A

Description

re rate atent PROCESS FOR THE PRODUCTION OF WASH-AND= WEAR CHARACTERISTISS IN WGVEN FABRICS OF REGENERATED CELLULOSE Bruno Stefan Vladimir Marek, Emmenbruclre, and Andre Michel Keller, Geneva, Switzerland, assignors to Societe de la Viscose Suisse, Emmenbrucke, Switzerland, a body corporate of Switzeriand N Drawing. Filed Feb. 11, 1960, Ser. No. 7,993

Claims priority, application Great Britain Feb. 19, 1959 Claims. (Cl. 28-76) This invention relates to the production of a drip-dry finish on woven fabrics of regenerated cellulose.

According to the present invention there is provided a process for the production of a drip-dry finish, which is fast to washing, on fabrics of regenerated cellulose which comprises immersing the fabrics in the absence of a catalyst, in an aqueous solution of ethylenediamine of 70 to 90% by Weight strength, allowing the ethylenediarnine to remain in contact with the fabric for 3 to- 30 minutes, removing the ethylenediamine and drying the fabric during or after the removal of the ethylenediamine.

The enthusiastic reception which textile materials made of man-made fibres have found with the public was mainly due to the fact that fabrics made from such fibres and apparel made therefrom need no ironing or at most a minimum amount of ironing after washing to make them again ready for Wear. This outstanding property is substantially due to three factors, namely (a) reduced creasing tendency in the wet state or, more precisely, ready recovery from any creasing while wet, combined with washresistance of any intentional creases previously produced by pressing or ironing; (b) ability to dry quickly, though some of this ability is also due to the structure of the fabric and the yarn, and above all to reduced water absorption and swelling; (c) dimens onal stability, that is to say at most a minimum susceptibility to stretching or shrinking during a wet treatment and drying respectively.

Attempts have, therefore, been made to impart an identical, so-called drip-dry, finish also to classic textile fibres, above all to cotton, by a suitable improving treatment, that to say by dressing them with synthetic resins or by modifying the cellulose. Subsequently, it was an obvious step to try to produce the results obtained on cotton also on fibres of regenerated cellulose, but hitherto this has been found to be rather ditficult owing to the differcnces between native cellulose and regenerated cellulose.

Moreover, the hitherto known processes for imparting a drip'dry finish to cellulose fibres involve considerable disadvantages, In the first place the drip-dry finish obtained on cellulose by chemical modification is by itself insufficient and the finish obtained by dressing with a synthetic resin is not sufiiciently resistant to washing since the effect diminishes with every successive Wash and disappears completely after about 20 to 30 Washes. Moreover, to achieve a satisfactory diminution of swelling, 1

the amount of these synthetic resins applied to the fibre must be so large that, on the one hand, the cost of the treated fabric is increased substantially and, on the other hand, the treated fabric becomes stiff, which in turn impairs certain mechanical properties of the fibre, particusaid shortcomings. The treatment according to the invention does not impair, but rather improves, the mechanical properties; no chlorine retention occurs, and the dripdry finish produced on the fabric is enhanced, not reduced, by successive washes.

Several processes have been described for treating textiles with nitrogenous organic bases, more especially amines, with a view to modifying certain properties of the textile material. In the first place, the present invention differs from those known processes in which a genuine chemical reaction between the amine and the cellulose takes place so that nitrogenous substitution products of cellulose are formed. Processes of this type generally require high temperatures and pressures and aim as a rule at an animalisation of the fibre to increase its affinity for acid dyestuffs. Since the regenerated cellulose treated by the present process does not contain any nitrogen, the aforementioned processes do not come within the scope of the present invention,

On the other hand, as far back as 1931, C. Trogus and K. Hess stated in a report on X-ray examinations of cellulose derivatives (Zeitschrift filr physikalische Chemie, Part B, volume 14, pages 387-395) that when native or hydrated cellulose is treated with a concentrated aqueous solution of hydrazine or an alkylenediamine, the lattice of cellulose undergoes certain changes above a certain limit concentration, in the case of ethylenediamine, for example, a concentration of the order of 38-42%.

The authors stated that by such a treatment adducts of an.

unknown type are apparently formed which in contact With water are broken down again. Whether after such a breakdown the changes that had initially occurred in the cellulose lattice persist or not, was not reported.

Subsequent researches concerned the question of whether cotton, after having been treated with a solution of an amine, was more suitable for being dressed with resins.

British patent specification No. 479,341 described a process for treating regenerated cellulose with amines, for example with an ethylene diamine solution of 55-65% strength, the swelling action of which improves the affinity of the fibre for cotton dyestuffs. According to that publication the treatment is performed during or immediately prior to the dyeing process, in either case without intermediate drying. The process of British patent specification No. 479,341 is particularly suitable for treating regenerated cellulose manufactured by hydrolysing a cellulose ester, for example acetyl-cellulose. It is known that such products have a very low dyestufi aifinity, while cellulose regenerated by the viscose or cuprammonium processes has so high an affinity that it is unnecessary or even undesirable to increase it any further.

In British patent specification No. 683,203 it is proposed to impregnate cord filaments of regenerated cellu' lose with a primary amine to improve their heat stability. British patent specification No. 750,088 describes a process for reducing the water absorption of regenerated cellulose, wherein vapours of alkylamines, hydrazine hydrate or ammonia gas are caused to act upon the moist fibre, advantageously under a pressure of 1. to 5 atmospheres (gauge). Finally, in British patent specifications Nos. 767,810 and 767,811 it is stated that the mechanical strength, stretchability and resistance to abrasion of cotton materials can be improved by treating the material in the stretched state with an amine, such as ethylene diamine and more especially a 3-substituted propylamine.

None of the aforementioned processes involves the essential features of the present invention which are that the material treated must be regenerated cellulose material (not cotton), the treatment agent must necessarily be ethylenediamine and not any other alkylene diamine, the fabric must be immersed in the solution, the solution must contain 6590% by weight of ethylenediamine, and after the treatment the ethylenediamine must be removed and the fabric dried during or after such removal. Applicants have found that only by adherence to these condi- 'tions is the characteristic finish imparted to the fabric.

The present invention is based on the observation that fabrics of regenerated cellulose undergo a peculiar change on being immersed merely in a solution of ethylenediamine of a suitable concentration by becoming strikingly soft, supple and slack. Compared with the handle imparted to a comparable untreated fabric by immersion in water, which may but need not contain a detergent, the change produced is particularly surprising. Even more surprising is, however, the fact that this change (provided the fabric is immersed for an adequate length of time) persists fully even after removing the ethylene diamine and washing and drying the fabric, although on being analysed the cellulose does not reveal any change having taken place in it. When the fabric is subsequently wetted or washed with water, the soft handle persists and in addition it is observed that any creasing that has occurred in wetting or during washing substantially disappears again in the following drying operation.

Thus, the change brought about by ethylenediamine is irreversible. The fabric retains its newly acquired properties through repeated washes, even when it is washed twenty to fifty times; actually, these properties are even enhanced by Washing. So far it has not been possible to find a tenable explanation for this observation. Is is also noteworthy that this phenomenon occurs only on regenerated cellulose but is practically absent from untreated or mercerized cotton, that is to say native cellulose.

Nor was it possible to obtain an identical effect by an analogous treatment with other amines. Moreover, most of the other amines are unsuitable for the industrial performance of the present process because they are either too costly or give off offensive smells or vapours or are connected with other inconveniences.

It will be realised that in the application of this treatment process to the production of a drip-dry finish several factors require special attention. As has been mentioned above, the concentration of the aqueous ethylenediamine solution plays a special role. It has been observed that any concentration above or below the limit range of 70% to 90% is capable of rapidly impairing the effect achievable by the present process.

It will be realised that the temperature and the time for which the ethylene diamine is allowed to act on the fibre likewise have a decisive influence on the ultimate effect. On the other hand, it has been observed that optimum temperature and optimum time of treatment are dependent on the concentration of ethylene diamine and on the fibre structure of the cellulose material under treatment and therefore must be adjusted for each specific treatment process.

A simple way of performing the treatment with the ethylene diamine consists, for example, in immersing the dry and desized fabric in the ethylene diamine solution, then expressing the fabric in any desired manner, for example between two rolls, washing the ethylene diamine out of it with water, if necessary neutralising the fabric with acetic acid, and finally drying it.

According to an advantageous variant of the process the fabric is immersed in the ethylenediamine solution for a short time only, the excess liquor is expressed, and the impregnated fabric is maintained for a specific time with the ethylenediamine present on it; during this operation it must be ensured that the heat released by the exothermic reaction does not reach the fabric. The fabric is then washed free from et-hylenediamine, if necessary neutralised, and finally dried.

According to another variant the fabric is immersed in the ethylene diamine solution, expressed, and then continuously passed over rolls through a closed chamber in which the bulk of the ethylenediamine remaining in the fabric is evaporated at an elevated temperature; the ethylene diamine can be recovered in a simple manner, and the reaction heat is compensated by the cold resulting from the evaporation of the ethylene diamine. As in the other variants mentioned above, the fabric is then washed free from ethylenediamine and finally dried.

In experiments conducted with the present process it has been observed that optimum results are achieved by working at a temperature not exceeding room temperature and advantageously with cooling, that is to say at a temperature ranging from 0 to 20 C., and that even at an immersion temperature of 40 C. a distinct diminution in the anti-crease effect is noticeable. Furthermore, it has proved advantageous to wash out the ethylenediamine in the cold, that is to say with water at 0 to 10 C. to compensate for the heat of hydration released by the dilution of the ethylenediamine remaining in the fabric. Furthermore, it has been observed that, quite generally, an immersion time below 3 minutes does not produce any appreciable effect while, on the other hand, immersion prolonged beyond 30 minutes does not improve the effect. In this connection a distinction must be made between the variant of the treatment in which the fabric is actually immersed for 3 to 30 minutes, and the alternative variants wherein the immersion is followed by an additional time of contact. In these latter cases immersion may last for only 30 seconds, provided the expressed fabric remains in contact with the ethylenediamine for a further period so that the total contact time is at most 30 minutes. Furthermore, determination of the extent of swelling has elicited the fact that in the case of highly oriented fibres of regenerated cellulose, of the type known by the name Polynosics, such as can be manufactured, for example, by the processes according to British specifications Nos. 650,896, 652,645 and 678,335 or 720,173 and as described in the journal Rayonne, Fibranne et Fibres Synthetiques, volume 9 (1959), page 531, the be ance between ethylenediamine and cellulose in the treatment liquor is established somewhat more rapidly than in the case of ordinary fibres of regenerated cellulose. On fabrics of cellulose fibres of this type the effect produced by the ethylenediamine treatment is particularly pronounced.

A fabric treated with ethylenediarnine by the present process, after having been washed and drip-dried, displays an anti-crease resistance in the wet state or a degree of recovery respectively which, as determined by the Monsanto method and by the method described in SVF Fachorgan fur Textilveredlung, volume 13 (1958), pages 247257 by Dr. B. S. Marek, Uber die Beurteilung des Wash-and-Wear Charakters von Geweben durch Knitter- 'bilder, corresponds to create pattern value 4 to 5, the value 5 in both methods being defined as the possible optimum.

It had not previously been known that such values could be obtained on staple fibres of regenerated cellulose which in accordance with their nature are particularly sensnrve to creasing in the wet state.

As mentioned above a satisfactory drip-dry finish on a fabric is not exclusively determined by the recovery from creasing in the wet state. Factors that must be taken into consideration at the same time are the speed at which the fabric dries, that is to say above all reduced swelling tendency, adequate dimensional stability, as well as adequate resistance to creasing when dry and, of course, also satisfactory mechanical strength.

Though the swelling tendency is distinctly diminished by the ethylene diamine treatment, such diminution does not reach a degree such as is desirable in drip-dry textiles. However, such a degree is easy to achieve by a suitable after-treatment as described hereinbelow.

Somewhat more difiicuit is the determination of the effect which the ethylenediamine treatment has on the dimensional stability. It has been observed that dimensional stability is influenced, on one hand, by the temperature prevailing during the ethylenediamine treatment, washing and drying and, on the other hand, primarily by the fact of whether the fabric is under tension or not during the treatment with ethylenediamine or during the washing or drying. e difference is most noticeable with fabrics dried with and without tension respectively: when a fabric dried in stentered state is subsequently wetted or washed, it undergoes shrinking, while the fabric dried in the loose state undergoes elongation. Moreover, the fact of whether the fabric is under tension or not during the treatment at the same time influences the property of recovery from creasing and the mechanical strength values. It can be shown that the resistance to abrasion can be affected to a certain extent by drying the fabric in the stentered state, while this has no decisive effect on the recovery from creasing.

Quite generally, it may be said that it is of advantage to perform the whole of the ethylenediamine treatment that is to say the immersion, optional contact with ethylenediamine solution in the expressed state, washing and dryingwith a minimum of tension. The dimensional stability of the fabric treated with ethylenediamine is however not substantially better than that of the untreated fabric and is as such not entirely satisfactory for drip'dry fabrics.

According to a further feature of the present invention regenerated cellulose fabric treated with ethylenediamine in the manner described above is subjected to an after treatment to improve the afore-said properties, the after treatment being selected from the following: treatment with formaldehyde, compressive mechanical shrinking, or incorporation -or application of resins (if desired by condensation on the fabric). The following examples will serve to illustrate the invention:

Example I This example shows the effect of the ethylenediamine treatment, performed by itself or in combination with a subsequent compressive shrinking operation, on the recovery from creasing, the mechanical strength and the swelling. The fabric used in this example was a calico fabric (linen weave) weighing 136 grams per sq. m., consisting of 31 filaments of Ne 40/1 per cm. in the warp and 37 filaments of Ne 40/1 per cm. in the weft and produced from viscose fibres of 7.5 deniers having a staple length of 38 mm.; the fabric was immersed for 5 minutes at room temperature in a commercial aqueous solution of ethylenediamine of 86.5% strength and then expressed to a weight increase of 100%, washed for 15 minutes with water at 1 C. and finally dried. The fabric was in the loose state during the whole treatment. The dry fabric was moistened, heated, subjected to a known mechanical compressive shrinking process on a mechanical compressing machine set to a nominal compression rate of 2, 4 and 6% respectively, and then conditioned.

The wear testing yielded the following results:

The data given above was obtained by the following tests:

Abrasion resistance: Number of cycles in the warp direction, determined with the Stollflex apparatus described in Text. Res. Journal 19 (1949'), page 394.

Crease pattern value: Comparison with the crease pattern scale described in SVF-Fachorgan 1.3 (195 8), page 247, determined after centrifuging the test specimens. Optimum value: No. 5. When instead of being centrifuged the test specimens were drip-dried as recommended for so-called drip-dry materials the fabrics treated by the present process had in all cases higher crease pattern values (shown in brackets in the table).

Shrinkage: Determined after washing at C., drying, sprinkling to a weight increase of' and ironing (iron set for rayon).

Bursting pressure in kgJsq. crn 1000 weight per sq. in.

Bursting index:

A crease pattern value of 3 to 4 for a (drip-dried) calico fabric of viscose fibres corresponds to a dressing with about 10% of a urea-formaldehyde or melamineformaldehyde condensation resin, but when such a dressing is applied the abrasion resistance of the treated fabric is much inferior to that of an untreated fabric. The abrasion resistance of a fabric treated by the present process is in fact improved, and when the fabric is dripdried, its crease pattern value is better than that which can be achieved by treatment with a resin. The shrinking tendency can be reduced to a degree satisfying all demands by suitably setting the degree of mechanical shrinking.

Example 11 This example illustrates the effect of tension applied during the treatment with ethylenediamine solution:

Two lengths of desized taffeta Weighing 98 g. per sq. m., consisting of 44 filaments Ne 47/1 per centimetre in the warp and 28 identical filaments per centimetre in the weft, produced from viscose staple fibres of 1.5 deniers and having a staple length of 40 mm., were immersed for 30 seconds in an aqueous ethylenediarnine solution of 87% strength at 10 C., expressed on a laboratory-type padder, and kept for 29.5 minutes at 20 C., during which time one length of fabric was left in the loose state while the other was stretched on a stenter. The two lengths were then washed in the loose state in water at 10 C., neutralised or acidulated with dilute acetic acid, again washed and dried without being stretched at 60 C.

After having been subsequently washed at 60 C., the fabric treated without stretching was accorded a crease pattern value of 4 and a wet-creasing angle of 118 (determined according to Monsanto, warp direction, recovery Crease pattern value Resistance Shrinkage (percent) Percent fabric (Values in brackets for to abrasion indicates elongation) Bursting index swelling drip-dried specimens) Variant (see below) 1 wash 25 washes 1 wash 25 washes 1 wash 25 1 Wash 25 1 wash 25 washes Washes washes iv arp weft Warp welt Variant a: Variant b: Variant c: Variant (l: Variant e:

untreated, without compressive shrinkage.

treated with cthylcnerliarnine, without compressive shrinkage.

after minutes) while the stentered length was accorded the value 4 to 5 and a wet oreasing angle of 124 C. A length of the identical fabric, not treated with ethylenediamine, was accorded the crease pattern value 2 to 3. The change in dimensions produced by the wash amounted in the case of the fabric treated in the loose state to +90% in the warp direction and to +32% in the weft direction; the corresponding figures for the fabric treated with stretching were +7.6% and +12% respectively.

Example III This example illustrates the change produced by the treatment with ethylenediamine on regenerated cellulose fibres of different nature. One length each of a taffeta fabric (weave as described in Example '11) produced from conventional viscose staple fibres and Polynosic fibres was desized, dried, conditioned and then immersed for 30 seconds in an aqueous ethylenediamine solution of 78% by weight strength, expressed on a laboratoryty-pe padder to a weight increase of 100%, fixed to a stente-r and together with it stored at 20 C. in a sealed bag of polyethylene foil. After 29.5 minutes the specimens were taken off the stenter and washed free from ethylenediamine, in the loose state, with tap water at The specimens were expressed to a weight increase of 80%, dried for 1 hour at 60 C. on a stenter, and then subjected to a two-stage condensation process (for minutes at 105 C. and then for 5 minutes at 160 C.). To remove the catalyst, the specimens were then washed at 40 C. and dried in stentered state at 60 C.

In the textile testing the viscose staple fibre fabric was accorded after a machine wash at 60 C. (goods-to-liquor ratio 1:10) a crease pattern value of 45, and the Polynosic fabric a value of 5. The dimensional change resulting from the wash amounted with conventional viscose staple fabric, in the warp direction, to 5% and with Polynosic fabric 1.5%. Untreated control of conventional viscose staple fabric showed a shrinkage of 7.5% in the warp direction when washed and dried under identical conditions. The swelling values were 45-47% which compares with 80% for the untreated fabric.

Example I This example illustrates a combination of the treatments with ethylenediamine, latex and resin. Desized lengths of the viscose taffeta fabric used in Example {I were padded with an immersion time of 30 sections with an ethylenediamine solution of 78% strength at C., kept for 29.5 minutes on a stenter in a ventilated drying cabinet at 100 C., then washed with cold water in the loose state, acidulated and then, without intermediate drying, impregnated with a polyacrylic ester latex containing free carboxyl groups (concentration 100 grams per litre, calculated as the dry content) in combination with 60 grams per litre of a reactant resin of the type of the cyclic ethylene ureas (commercial product Resloom E50). The dressed specimens were dried on stenters at 60 C. and then subjected to a two-stage condensation (for 15 minutes at 105 C. and then for 5 minutes at 150 C.). A like treatment was applied to specimens of the fabric treated with ethylene diamine but not with the resin and the latex.

The textile treating produced the following results: While the specimens treated only with ethylenediamine, then washed and dried on a stenter, on subsequent washing at 60 C. shrunk in the warp direction by about 11% and in the weft direction by 3%, the specimens which had been additionally treated with the relatively very small amount of resin displayed a satisfactory dimensional stability: after one wash the shrinkage in the warp and weft directions was 1.1% and 1.2% and after 10 washes 2.0 and 1.5 respectively.

The specimens treated with ethylenediarnine but not with resin were accorded a crease pattern value of 5, and those treated with ethylenediarnine, resin and latex corresponded to the crease pattern valve 4.

When specimens of the above fabric, without a preliminary ethylene diamine treatment, were treated with 2 /2 times the amount of resin, that is to say with 150 grams of Resloom E50 per litre and the identical content of latex, with zinc nitrate as catalyst, their crease pattern value was found to be 3-4, which was accompanied by a considerable diminution in the abrasion resistance.

This example thus shows clearly that the ethylenedia-mine treatment combined with a dressing with resin gives optimum results with an amount of resin that is much smaller than that required for producing finishes of the known kind, and at the same time the disadvantages involved in resin dressing are substantially prevented.

We claim:

1. A process for improving the wet crease resistance and for producing a drip-dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at 0 to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diarnine of 70 to strength by weight in excess of that which the fabric can take up, allowing aqueous solution of ethylene diamine to remain in contact with the fabric for 3 to 30 minutes, removing the ethylene diamine from the fabric by washing with water and then drying the fabric.

2. A process for improving the wet crease resistance and for producing a drip-dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at 0 to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diamine of 70 to 90% strength by weight in excess of that which the fabric can take up, removing the fabric from said solution and expressing excess aqueous solution of ethylene di amine from the fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric which is not less than based on the weight of the initial fabric to remain in contact with the fabric for a time suflicient to give a total time of contact between the fabric and the aqueous solution of ethylene diamine of 3 to 30 minutes, washing the fabric with water to remove ethylene diamine and drying the fabric.

3. A process for improving the wet crease resistance and for producing a drip-dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at 0 to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diamine of 70 to 90% strength by weight in excess of that which the fabric can take up, removing the fabric from said solution after a lapse of 0.5 to 5 minutes and expressing excess aqueous solution of ethylene diamine from the fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric which is not less than 100% based on the weight of the initial fabric to remain in contact with the fabric for a time sufficient to give a total time of contact between the fabric and the aqueous solution of ethylene diarnine of 3 to 30 minutes, washing the fabric with water to remove ethylene diarnine and drying the fabric.

4. A process for improving the wet crease resistance and for producing a drip-dry finish on a Woven fabric of regenerated cellulose. which comprises immersing the fabric at 0 to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diarnine of 70 to 90% strength by weight in excess of that which the fabric can take up, removing the fabric from said solution and expressing excess aqueous solution of ethylene diamine from the fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric to remain in contact with the fabric which is not less than 1% based on the weight of the initial fabric for a time sufficient to give a total time of contact between the fabric and the aqueous solution of ethylene diamine of 3 to 30 minutes, washing the fabric with water to remove ethylene diamine, drying the fabric and subjecting it to compressive shrinkage to improve its dimensional stability.

5. A process for improving the wet crease resistance and for producing a drip-dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at O to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diamine of 70 to 90% strength by weight in excess of that which the fabric can take up, removing the fabric from said solution and expressing excess aqueous solution of ethylene diamine from the fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric which is not less than 106% based on the weight of the initial fabric to remain in contact with the fabric for a time sufficient to give a total time of contact between the fabric and the aqueous solution of ethylene diamine of 3 to 30 minutes, washing the fabric with water to remove ethylene diamine, impregnating the fabric with formaldehyde, drying the fabric and condensing the formaldehyde on the fabric, again washing with water and drying, whereby swelling in water is reduced and the dry crease resistance and dimensional stability of the fabric are improved.

6. A process for improving the wet crease resistance and for producing a drip-dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diamine of 70 to 90% strength by weight in excess of that which the fabric can take up, removing the fabric from said solution and expressing excess aqueous solution of ethylene di mine from the fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric which is not less than 100% based on the weight of the initial fabric to remain in contact with the fabric for a time sufficient to give a total time of contact between the fabric and the aqueous solution of ethylene diamine of 3 to 30 minutes, washing the fabric with water to remove ethylene diamine, impregnating the fabric with a precondensate of a thermosetting amine-formaldehyde resin, drying the fabric and condensing the precondensate on the fabric.

7. Process according to claim 6, comprising applying to the fabric an ester of polyacrylic acid together with the resin precondensate.

8. A process for improving the wet crease resistance and for producing a drip'dry finish on a woven fabric of regenerated cellulose, which comprises immersing the fabric at 0 to 20 C., in the absence of any catalyst, in an amount of an aqueous solution of ethylene diamine of to strength by weight in excess of that which the fabric can take up, removing the fabric from said solution after a lapse of 0.5 to 5 minutes and expressing excess aqueous solution of ethylene diamine from the fabric which is to a weight increase of the fabric not less than based on the weight of the initial fabric, allowing the aqueous solution of ethylene diamine adherent to the fabric to remain in contact with the fabric for a time sufficient to give a total time of contact between the fabric and the aqueous solution of ethylene diamine of 3 to 30 minutes, washing the fabric with water to remove ethylene diamine and drying the fabric.

References Cited in the file of this patent UNITED STATES PATENTS 2,189,918 Moncrieff Feb. 13, 1940 FOREIGN PATENTS 479,341 Great Britain Feb. 3, 1938 750,088 Great Britain June 6, 1956 OTHER REFERENCES Trogus: Zeitschrift fur physikalische, Chemie, Part B, vol. 14, pp. 387-395 (1931).

Claims

4. A PROCESS FOR IMPROVING THE WET CREASE RESISTANCE AND FOR PRODUCING A DRIP-DRY FINISH ON A WOVEN FABRIC OF REGENERATED CELLULOSE, WHICH COMPRISES IMMERSING THE FABRIC AT 0 TO 20*C., IN THE ABSENCE OF ANY CATALYST, IN AN AMOUNT OF AN AQUEOUS SOLUTION OF ETHYLENE DIAMINE OF 70 TO 90% STRENGTH BY WEIGHT IN EXCESS OF THAT WHICH THE FABRIC CAN TAKE UP, REMOVING THE FABRIC FROM SAID SOLUTION AND EXPRESSING EXCESS AQUEOUS SOLUTION OF ETHYLENE DIAMINE FROM THE FABRIC, ALLOWING THE AQUEOUS SOLUTION OF ETHYLENE DIAMINE ADHERENT TO THE FABRIC TO REMAIN IN CONTACT WITH THE FABRIC WHICH IS NOT LESS THAN 100% BASED ON THE WEIGHT OF THE INITIAL FABRIC FOR A TIME SUFFICIENT TO GIVE A TOTAL TIME OF CONTACT BETWEEN THE FABRIC AND THE AQUEOUS SOLUTION OF ETHYLENE DIAMINE OF 3 TO 30 MINUTES, WASHING THE FARBIC WITH WATER TO REMOVE ETHYLENE DIAMINE, DRYING THE FABRIC AND SUBJECTING IT TO COMPRESSIVE SHRINKAGE TO IMPROVE ITS DIMENSIONAL STABILITY.