US2219375A - Process of treating textiles and product - Google Patents

Description

. Patented Oct. 29, 1940 I I UNITED STATES PATENT OFFICE.

PROCESS OF TREATING TEXTILES AND PRODUCT I Gustave Widmer, Basel, Switzerland, and Louis Klein, Frankford, Philadelphia, Pa., assignor to Rohm & Haas Company, Philadelphia, Pa.

No Drawing. Application Au ust 31, 1934, Serial No. 742,284

8 Claims. (01. 91-70) This invention relates to securing improved efproduct acts as 'a binder for other materials such fects on textiles by the use of non-resinous reacas starch, pigment, talc, etc. On the contrary,

tion products of carbamid and formaldehyde. the effect secured results from the precipitation of Methods have been proposed in the past for treatthe carbamide-formaldehyde product itself in an ing textiles with reaction products of urea an insoluble form. 5 formaldehyde. In U. S. Patent No, 1,355,834, Our process is particularly applicable to the John indicates that when urea and formaldehyde production of textile fabrics, characterized by a are allowed to react for a short time at a high reduced tendency to wrinkle or crease. Until temperature, a product results which is still water now, the commercial process of preparing fabrics,

m soluble and which is useful for impregnating texcharacterized by reduced tendency to wrinkle has til comprised impregnating fabrics with a dilute In U. S. Patent No. 1,871,087 dimethylol urea is acidified solution of a condensation product of used in combination with other substances to prourea and formaldehyde, subsequently drying duce local effects on textiles. It serves essentially them, and hardening the condensation product by m as a binder for pigments. In U. S. Patent No. heating the impregnated fabric at a relatively 1,926,063,1'eaction products of urea and formaldehigh temperature (about 330 F.). Following hyde serve as a binder for a filler, and the producthis, an essential part of the process was the soaption of filled fabric with improved water resisting and rinsing to remove excess resin between ance is thus achieved. In U. S. Patent No. 1,693; the fibers. The fabric was then dried, and fin- 926, reaction products of urea and formaldehyde is ed in he us al way. T e di l y of producare used in the treatment of wool, silk, and other ing a uniform and satisfactory urea-formaldeanimal fibers. The resin serves to inhibit the dehyde condensation product has served as one of structive action of alkaline agents added later in the chief barriers in the commercial development the process of treating the textiles. In U. S. Patof this process.

cut No. 1,734,516, which describes a particular It is well known to those skilled in the art that 25 method of crease-proofing textiles, urea formalconsiderable difficulty is encountered in the mandehyde resins are described among others. In ufacture of urea formaldehyde condensation order to obtain a satisfactory result, it is necesproducts, particularly those n Which the condensary to carry out the reaction between the urea sation is arrested before completion. This is due and formaldehyde very carefully. The proper demainly to the sensitivity of these products to 3 gree of resinification must be attained, or otherslight chances in temperature and to the effect of wise the treated fabric may .be stiff and brittle insmall amounts of acids, bases and salts. If the stead of soft and flexible. Moreover, in addition cidi y or a i ity and salt ntent of the soluto accurate control of production of the resin, it is tions are not very accurately adjusted, precipitaessential that the entire process of heating and tion of the condensation product occurs and this 25 subsequent washing to remove excess resin berenders the material unsuitable for the productween the fibers be carefully performed. All tion of crease-proof fabrics. Furthermore, this these operations require highly skilled labor in process is generally carried out in finishing plants addition to a considerable amount of technical which are, as a rule, not in a position to give adesupervision, quate technical supervision to the production of 40 Our invention differs from the known processes the resin and thus it is easy to understand why in which carbamide-formaldehyde prod t hav considerable variability in the finish due to the been applied to textiles, in that it makes possible non-uniformity of the resin, was encountered. for the first time the production of improved fin- Moreover, solution of Such resins prepared for ishes by a simple and inexpensive process. Decrease-proofin ve been rather unsuitable and pending on the. actual conditions employed, vary it is not unusual to find a considerable amount of ing effects are produced. In particular, it is posthe resin precipitated shortly after the solution is sible to secure fullness, resistance to fraying, inprepared. This condition is particularly noticecreased wet strength in rayons, and fabrics charable after the solutionshave been acidified and acterized by a reduced tendency to wrinkle. the precipitation often occurs within a few min- These results are secured by using non-resinous utes after the addition of the acid. This of carbamide-formaldehyde reaction products in course, renders the material unsuitable for use in fairly concentrated solution for impregnation of crease-proofing fabrics. Solutions suitable for the textile fabrics, and subsequently producing an use under factory conditions may be stabilized by insoluble product by the application of heat. the addition of such compounds as urea, thiourea, Small amounts 0 catalysts may or may not be dicyandiamide, sodium sulphate, etc., according added to the solution used for impregnation. to our copending application No. 664,554, filed Other substances are sometimes added to stabilize April 5, 1933, of which the present invention is a the solution. In no sense, however, should it be continuation-impart.

construed that the carbamide-formaldehyde It is an object of this invention to provide a temperature. In this way the finished product is stronger than those in which the hardening of the urea-formaldehyde product is carried out at high temperatures because at these high temperatures the individual fibers ofthe fabric are adversely affected.

In order to obtain the best crease-proofing effect, it is necessary for the urea-formaldehyde material to penetrate the individual fiber as much as possible. Ifa substantial amount of the material should be left on the surface of the fabric, the entire fabric'is stifiened and made brittle, whereas if the material penetrates the fabric and all of it remains there, this efi'ect is not present and the finished fabric is crease-proof.

Urea-formaldehyde condensation products are colloidal in nature and consequently the individual particles or micelles are so large that they cannot penetrate the individual fibers.

We have now found that if instead of using an intermediate condensation product of urea and formaldehyde, which is resinous in nature, we

use a reaction product of non-resinous nature, the material will penetrate the individual fibers of the fabric and on subsequent drying and hardening, a considerably improved crease-proofing effect is obtained. For this purpose we use the initial reaction product of urea and formaldehyde, before any condensation whatever has taken place. In other words, starting with urea and formaldehyde, our impregnating solution contains only dimethylol urea ormonomethylol urea,

or both, and these. compounds are present in the molecular state and are not condensedto the resinous or'colloidal material. I

Many advantages result from the use of this material for crease-proofing fabric, particularly with respect to the handling of the material by the workman. This material can be made in solid forni and all that is necessary before use is to dissolve it in the proper amount of water. If desired a'catalyst may also be added, but this is not necessary. Solutions thus prepared are far more suitable and less sensitive to added materials than are the solutions of the intermediate condensation products. It is therefore not necessary to make up fresh solutions continuously when operating on a large scale, but a large stock of the suitable solution can be made up at one time. Moreover, it is'not necessary to exercise extreme care in keeping these solutions as is" the case when solutions of the intermediate resinous condensation products are used.

We have also found that by properly adjusting the composition of the solution of the carbamid formaldehyde reaction product, that it is possible to eliminate the use of an acid catalyst and this also assists in imparting better keeping qualities to the solutions. For instance, if a mixture of eight parts of dimethylol urea, one part of thiourea and two parts of anhydrous sodium sulphate is made up into a 20% solution in water and used to impregnate fabric, the material absorbed by the fabric may be fully cured in two minutes at a temperature of 330-340 F., without the use of any catalyst. This temperature anaerois rather high for the treatment of fabrics and a the curing better product could be obtained if temperature could be reduced to 275 'We,have found that the use of a special catalyst plants, no apparatus is available which could heat the fabric as high as'330 F. By using this special catalyst, however, it is possible to obtain a very satisfactory product within two to four min utes, attemperatures of 230 to 250 F., and good results may be obtained ,even at temperatures as low as 215 to 220 F.

, The catalysts which are particularly efiective for this purpose are salts of moderately strong acids and weak volatile bases. We have found that diainmonium phosphate is particularly effective as a catalyst for this purpose. The action of this type of salt is probably due to the fact that on heating, the volatile basic group is va-' porized, or if the base is ammonia or an amine, it combines with thefree formaldehyde, thus leaving a moderately. strong acid in a solution which accelerates the conversion of the resin to the. final insoluble state and makes possible the complete insolubilizing temperature. Salts of strong acids are objectionable because the presence of even traces of strong acid in the fabric would be detrimental are used, such for instance, as ammonium acetate, the catalytic efiect is very weak. If a strong acid were to be used alone, the solution wouldprobably gelatinize very rapidly and thus become unfit for the purposes of the present invention, because when the solution colloidal material is formed'and this would not penetrate the individual fibers of the fabric.

In carrying out our process, we prefer to use a solution containing approximately 10-30% of the initial addition product of the carbamide and formaldehyde such as for example, dimethylol urea containing a catalyst. The fabric is impregnated with this solution and then squeezed between rollers. The amount of the material taken up by the fabric is dependent on the nature of the fabric, the concentration of the solution employed, and the result desired, and is usually approximately equal. to the original dry weight of the fabric. The impregnated fabric is then dried and heated. to the desired temperature for two to four minutes in order to harden the methylol urea and render it insoluble. Following this operation, the fabric may soap and water so as to remove any particles F. or less. Y

ofthe resin at a lower be washed with of resin which may be adhering to the outside Y of the fibers, and dried.

In the following examples and claims, the term formaldehyde is used in its widest sense, including its polymers.

The following examples are given by way of illustration and are not to be considered a limitation of the scope of 'the invention. Many deviations will suggest themselves to anyone versed in the art and all such are included in the spirit of the invention, which is limited only by the appended claims. In these examples parts are by weight.

Example 1.25 parts of a mixture of equal parts of urea and dimethylol urea are dissolved in '75 parts of water and part of glacial acetic acid or A part of tartaric acid is added. Cotton or rayon cloth is impregnated with this solution and squeezed through rollers so that the amount of solution taken up is approximately equal to the original weight of the fabric. The cloth is then dried at a low temperature and cured by treating it with a hot iron for 2 to 4 minutes at 330 F.

.It is then washed with soap and water, rinsed and dried. The resulting fabric has a good feel and an improved resistance to wrinkling. This resistance to wrinkling is not affected to any appreciable extent by subsequent laundering.

Example 2.--l5 parts of dimethylol urea is dissolved in 85 parts of hot water and after cooling V2 part of glacial acetic acid is added. Cotton voile is impregnated with this solution and treated as in Example 1. The resulting fabric is crease-proofed and has the same resistance to subsequent laundering as a fabric obtained according to Example 1. Instead of the dimethylol urea, monomethylol urea may be used.

Example 3.-A sample of rayon or cotton fabric is impregnated with a 25% solution of dimethylol thiourea and squeezed between rollers so that the the fabric has taken up about 100% of its dry weight of solution. The fabric is then dried and cured by heating for 2 to 4 minutes at 330 F. The resulting fabric is very resistant to wrinkling.

Example 4.--A mixure containing 4 parts of dimethylol urea and 1 part of thiourea is made up to a solution in water. A sample of cloth treated with this solution by the procedure given in Example 3, yields similar results.

Example 5.--A mixture of 8 parts of dimethylol urea, one part of thiourea and two parts of anhydrous sodium sulphate is made up to a solution in water. A sample of cloth impregnated with this solution and treated according to the procedure given in Example 3, has very good wrinkle resisting properties.

Example 6.-'-A mixture of .4 parts of dimethylol urea and one part of anhydrous sodium sulphate is made up into a 25% solution in water, to which is then added V4 part tartaric acid. Cloth impregnated with this solution according to the procedure given in Example 3 may be cured in 4 to 8 minutes at proofed material.

Example 7 .F-A mixture of '4 parts of dimethylol urea. one part of dicyandiamid and one part of sodium nitrate is made up into a 25% solution in in Example 5, ya part water to which is added /4 part of tartaric acid. This solution may be used for crease-proofing according to the method given in Example 3 and yields a very satisfactory product.

Example 8.-To 100 parts of the solution used of diammonium phosphate is added. and the resulting solution used to impregnate cotton clo The cloth is then squeezed between rollers until the amount of solution absorbed is equal to about 75% of the dry weight of the fabric. It is then carefully dried at 190 F; and finally heated for 3 minutes to 240 F. After finishing in the usual way, an improved resistance to wrinkling which is not very readily removed by ordinary laundering. 7

Example 9.-A mixture of 4 parts of dimethylol urea and one partof sodium sulphate is made up to a 20% solution in water to which is then added one part of di-(mono-methylammomum) phosphate and the resulting solution is used to impregnate cotton voile. The impregnated fab- 'ric is treated as in Example 8 and after fir'iishinl has very good crease-resisting pro e other non-resinous addition products of form- 312 F. to yield a well crease-v aldehyde and carbamid or its derivatives, such as dimethylol thiourea, monomethylol thiourea, etc., may be used in place of the dimethylol urea in the foregoing examples without departing from the spirit of the invention.

It is to be understood that, although the step of washing the fabric after curing the resin is often desirable, it is not a necessary not essential part of the process.

We claim:

1. The process of creaseproofing textile fibers comprising impregnating the fibers with a 10-30% solution of an addition product of carbamide and formaldehyde free from condensation products thereof, and a catalyst which is an ammonium salt of a moderately strong acid until the fibers take up from-10-30% of their dry weight of said addition product, drying the impregnated fibers and insolubilizing the carbamide-formaldehyde product by heat.

2. The process of creaseprooflng textile fibers comprising impregnating the fibers with a resin free l030% solution of an addition product of carbamide and formaldehyde to which has been added 0.5% of diammonium phosphate until the fibers take up from 10-30% of their dry weight of said addition product, drying the impregnated fibers and insolubilizing the carbamide-formaldehyde product by heat.

3. The process of creaseproofing textile fibers comprising impregnating the fibers with a resin free l0-30% solution of an addition product of carbamide and formaldehyde which also contains sodium sulfate in amount suflicient to stabilize said solution, and as a catalyst 0.5% of diammonium phosphate until the fibers take up from l0-'-30% of their dry weight of said addition product. drying the impregnated fibers and in solubilizing the carbamide-formaldehyde product by heat.

4. Process of improving the crease-resistance of textile fabrics which comprises impregnating the fabric with a solution of a reaction product of urea and formaldehyde consisting mainly of a methylol urea and containing a potentially acid ammonium salt and then heating the impregnated fabric to insolubilize the resin.

5. Process of improving the crease-resistance of textile materials which consists in impregnating the material with a solution of partially condensed resin components which is unstable in acid solution, and which solution contains a potentially acid ammonium salt, and heating the impregnated material to insolubilize the resin and produce a crease-resisting product.

6. Process of improving the crease-resistance of textile material which consists in impregnating the material of urea and acid solution,

formaldehyde which is unstable in which solution contains a potentially acid ammonium salt, and heating the impregnated material to insolubiiize the resin and produce a crease-resisting product.

7. Process as in claim 5 in which an ammonium salt of-a strong mineral acid is used.

8. A crease-resisting textile fabric containing a synthetic resin insolubilized by heating a par-- tially' condensed resinous product in situ in presence of acid liberated from an ammonium salt of a mineral acid.

GUBTAVE wmmm. I-DUIB KLEIN.

with a partially condensed solution.