US2846337A - Magnesium chloride catalyst for modified urea resins - Google Patents

Description

MAGNESKUM CHLORIDE CATALYST FOR MQDIFIED UREA RESINS Theodore F. Cooke, Martinsville, Louis J. Moretti, Somerville, and Robert C. Conn, Bound Brook, N. J., assignors to American Cyanamid Company, N ew York, N. Y., a corporat on of Maine No Drawing. Application September 28, 1955 Serial No. 537,289

11 Claims. (Cl. 117139.4)

The present invention relates to stable aqueous solutions of certain modified urea resins containing magnesium chloride as a catalyst and finishing textiles with such mixtures.

Textile materials have long been treated with certain resins to impart various desirable qualities such as wrinkle resistance and shrink resistance. To expedite the curing of the impregnated fabric and to provide a waterinsoluble finish, it has been customary to add a catalytic agent to the treating bath in order to obtain curing times sufiiciently short for large-scale commercial operations. The usual catalysts have been either acidic in nature or latent acid-forming substances. Even the latter develop an acid condition in a textile treating pad bath with the passage of time, and pad bath stability has been a continuing problem in the industry. In addition, it has not been possible to pre-mix a catalyst with the resins which are usually sold as concentrated aqueous solutions because of the instability of such mixtures. This instability is manitested in solutions becoming turbid or hydrophobing, after a comparatively short time. A one-package premixed textile finishing agent and catalyst would be advantageous to the textile finisher in reducing his problems of preparing a pad bath in proper proportions.

An object of the invention is to provide stable aqueous solutions of certain resins containing magnesium chloride.

Another object of the invention is to provide concentrated premixed aqueous solutions of certain modified urea resins premixed with magnesium chloride as a catalyst.

A further object of the invention is to provide relatively dilute aqueous solutions of certain modified urea finishing agents and a catalyst which have exceptional stability.

Still another object of the invention is to provide an apparent to those skilled in the art, especially upon consideration of the detailed disclosure hereinbelow.

The above and other objects and advantages are obtained with the present invention which comprises astable aqueous dilute or concentrated solution contain-j magnesium chloride and at least one agent of the group'- consisting of methylated methylol urea, partially poly-flu" merized methylated methylol urea, methylated and un'-' methylated methylol ethyleneureas and methylated and unmethylated methylol 1,2-propyleneureas. The invention also includes treating textile materials with such solutions and curing the impregnated material to convert 2,846,337 Patented Aug. 5', 1958 ICQ 22 the agent to the water-insoluble state. In addition, it encompasses textile treatments wherein the impregnated fabric is dried and mechanically finished more than twenty-four hours later followed by a curing operation.

The catalyst-containing mixtures of the present invention produce a number of beneficial effects. They impart a high degree of wrinkle recovery and shrink resistance to a wide variety of fabrics. Moreover, pad baths containing these mixtures have outstanding stability against hydrophobing, separation, or gelling. Also, the preparation of pad baths is greatly simplified by the high stability of the mixtures in concentrated aqueous solution which permits their sale in a single package rather than separately as catalysts and finishing agents. Long aging of the concentrated solutions does not cause separation or impair the effectiveness of the resins for imparting shrink resistance and wrinkle resistance.

The treatments ofthis invention are applicable to a wide variety of fabrics and textile fibers including woven, knitted, felted, and nonwoven fabrics. If desired, the application may be made to raw fibers or to yarns or threads. However, it is preferred to treat one of the above-mentioned fabrics to obtain the optimum benefits of the invention. The fiber content of the fabric may comprise any of the cellulose fibers including cotton, viscose rayon, cuprammonium rayon, flax and ramie; wool; nylon of both the adipamide and caprolactam types, as well as related super polyamides; homopolymers and copolymers of acrylonitrile; polyester fibers such as cellulose acetate, including cellulose triacetate, polyethylene glycol terephthalate and other synthetic filaments.

The greatest utility of the finishing treatments appears to be with cotton and rayon fibers and blends thereof with other textile fibers.

The invention is specific to certain modified urea resins, which term is used herein to include partially or wholly methylated methylol ureas and their water-soluble lower polymers as well as methylol ethyleneurea, methylol 1,2- propyleneurea and methyl ethers of these cyclic ureas. These resins commonly contain from about 1.3 to 2 mols of combined formaldehyde per mol of urea or cyclic urea. In the case of the methyl ethers, the degree of methylation (that is, the percent of available methylol groups which are converted to methoxymethyl groups) may range from about 30 up to Other resins such as methylated or unmethylated methylol melamine and unmodified urea-formaldehyde do not possess a stability of the same order in admixture with magnesium Conventional catalysts for textile resins such as amine hydrohalide salts, ammonium sulfate, various ammonium-phosphates, ammonium chloride, and acids such as oxalic and orthophosphoric acids all form solutions with the modified urea resins which are comparatively acid either initially or after standing for a comparatively lim- :ited period. Accordingly, these are not suitable for use in premixed resin-catalyst concentrated blends. Also, pad baths prepared with such catalysts have a relatively limited life.-

. For maximum stability the pH of the aqueous resinmagnesium chloride solution, either concentrated or as dilute as about 2% solids, should be between about 7.0 and about 10.5; and this may be adjusted, if necessary, by the addition to the mixture of a small amount of magnesium hydroxide or any compatible alkaline material such as the carbonates, bicarbonates, or hydroxides of sodium, potassium, or ammonia, amines and other organic bases. Above a pH of about 10.5, an undesirable turbidity is produced. Such alkalinity corresponds to a content of about 1% or less magnesium oxide based on the total Weight of anhydrous magnesium chloride. A similar etlect is not obtainable with mixtures of these resins with other catalysts, inasmuch as the alkalinity seriously impairs the catalytic effect of such other catalysts.

In preparing premixed finishing agents containing catalysts, it is desirable to have as concentrated a product as possible in order to minimize shipping costs; hence, the resin solids content should range from about upward and preferably between about 60% and 90% by weight. The magnesium 'chloride content may vary between about 2% and about 25% based on the weight of the resin solids. Pad baths commonly contain between about 2.5 and about resin solids, but the concentration may be as low as about 1% or as high as about 50% or more where a stiff finish is sought.

The treatment may be carried out in conventional manner with the add-on or deposit of resin on the fabric controlled by selecting the proper pad bath concentration for a particular textile material and regulating the pressure applied to the squeeze rolls. While the dry pickup may range from about 1% to about 50%, a deposit of between about 2% and about 25% based on the dry fiber weight is recommended for most purposes. After impregnation, the fabric may be dried and cured either simultaneously or in separate operations. The curing may be accomplished by exposing the fabric to temperatures between about 275 F. and the point at which degradation in the particular fabric commences, usually above 400 F., for a period sufficient to convert the finish to a substantially water-insoluble state. In general, temperatures of about 275 to 375 F. for periods between about 30 seconds and about 30 minutes are recommended. Curing by exposure to much hotter radiant elements for a briefer period is also suitable, inasmuch as the temperature of the fabric is doubtless about the same as produced in ovens operating at lower temperatures. If a separate drying operation is employed, temperatures of about 180 F. to about 250 F. are suitable for most purposes. After curing, the textile material may be subjected to a conventional process wash to remove any unreacted resin; but this is not necessary, as fabrics treated according to this invention are not subject to acid degradation and have no tendency to pnoduce dermatitis.

After a treated fabric has been dried at a temperature below that at which curing of the finish takes place, it may be stored for considerable periods without any deleterious eifects such as developing odor or a reduction in the final wrinkle resistance and shrink resistance. This is an outstanding feature which is not possessed by other resin-catalyst mixtures, inasmuch as the treated fabric may be dried in one plant and then transported considerable distances to another plant for mechanical finishing or allowed to stand until production conditions permit large-scale embossing or pleating operations. While pleating machines, embossing rolls, Schreiner and friction calenders and other equipment capable of producing a three-dimensional configuration or a glazed finish are commonly heated to a degree which undoubtedly produces at least some curing, it is thought best to insure complete curing by subjecting a fabric mechanically finished in this manner to a complete curing operation, as set forth above, to stabilize the finish against laundermg.

For a better understanding of the nature and objects of the present invention,'reference should .be had to the following examples wherein all proportions are given in terms of weight unless otherwise specified therein. These examples illustrate the invention and are not to be construed as limitations thereon.

EXAMPLES Concentrated aqueous resin solutions are mixed with concentrated aqueous solutions of various catalysts to produce mixtures of active ingredients in the proportions set forth in the table below. The resin designated MMU is essentially monomeric methylated dimethylol urea or bismethoxymethyl urea, and PMMU stands for a water-soluble partially polymerized 70% methylated dimethylol urea. The latter resin is prepared by mixing 10.3 mols of water, 37.5 mols of methanol and 63.5 mols of 91% paraformaldehyde with sufficient triethanolam'ine to produce a pH of 8.2, adding 28.4 mols of urea and refluxing for 2% hours at 175 F. After cooling to F., 88.5 mols of methanol is added, and the pH is adjusted to 3 with oxalic acid. After refluxing at 162 F. for 25 minutes, the reaction mixture is neutralized with triethanolamine and concentrated under vacuum.

The dimethylol ethyleneurea designated by DMEU is prepared in known manner charging 2 mols of formaldehyde per mol of ethyleneurea and contains a relatively small amount of uncombined formaldehyde. The amine catalyst in the table hereinbelow consists of hydrochloride salts of mixed isopropanolamines. -The stability of the resin-catalyst mixtures is determined over various periods at three different temperatures in both the concentrated state and after dilution with water to a content of 5% solids. Stable samples show no turbidity, separation or crystallization when concentrated and no hydrophobing with the formation of a precipitate or turbidity upon dilution. The diluted mixture approximates the concentration of the pad baths in which fabrics undergoing a resin treatment are immersed and the concentrated form is a one-package resin treatment in salable form which requires only dilution to the desired pad bath strength. Comparative examples denoted by letters are given for comparison with the numbered examples of the present invention.

Table Weight percent Stability in Days at Example Resin Solids Catalyst Solids Water 50 C. 37 0. 25 C.

58.7 PMMU. 34.4 63.0 PMMU" 26.3 65.3PM1\IU 4 30.7 69.6 PMMU" 2 28.0 27.9 MMU. a ass 28.3 MMU 1. 70. 0 20.0 MMU.-- 1. 10. 0 42.2 DMEU- 5 52.8 44.4 DMEU 1. 48.1 45.5 DMEU 3.1 51.8 41.5 DMEIL- 1.7(NH4)=SO4- 50.8

1 Yellow-orangeeolor develops on aging. I Orystaillzes and yellows on aging.

The solution in Comparative Example A is on the acid side, B has a pH of 6, and C has a pH of 4.3, whereas the mixture of Example 1 has a pH of 7.9 after standing three days. The examples demonstrate the outstanding stability of the novel mixtures in contrast with those containing other catalysts.

The examples hereinbelow are carried out by diluting certain of the aged resin-catalyst mixtures described in the above table sufiiciently to provide a dry pickup of 5% resin solids on 80 x 80 cotton percale (145 wrinkle recovery untreated) and on rayon gabardine in a con ventional pad bath with the squeeze rolls set for 83% expression. All samples are dried at 225 F. and the dry impregnated cotton percale is cured for 1.5 minutes at 350 F. while the rayon gabardine is cured for 3 minutes at 300 F. in a ventilated oven. In the case of the cotton material, only the wrinkle recovery is determined by the roller pressure method and only the hand of the rayon is evaluated.

For comparison, certain lettered examples are set forth using freshly prepared resin which is mixed with the catalyst immediately prior to treating the fabric.

EXAMPLE 4 Freshly prepared PMMU resin and a solution of magnesium chloride are mixed in a pad bath and diluted to a concentration of 6% resin solids and 0.72% magnesium chloride. After treatment therewith, the cotton percale is found to have a wrinkle recovery of 216 and the rayon gabardine has a soft hand.

EXAMPLE 5 A resin-catalyst mixture according to Example 1 is aged for over one year at 25 C. and then diluted to a resin solids content of 6% to form the pad bath. Cotton percale finished with this mixture has a wrinkle recovery of 220, and a similarly finished rayon gabardine has the same hand as the sample in Example 4. It is apparent that no deterioration of the resin-catalyst mixture results from aging over an extended period prior to application.

EXAMPLE 6' A pad bath is made up to a content of 6.0% DMEU solids from a fresh commercial product and 0.72% magnesium chloride. The wrinkle recovery of cotton percale finished therein is 252, and the hand of a similarly treated rayon gabardine is soft.

Mercerized cotton yarn is passed through the same pad bath and dried and cured in the same manner. This yarn is fed to a loom for weaving percale as the warp with an untreated mercerized cotton yarn being fed as the filling. The resulting novelty percale has substantially improved wrinkle recovery and shrink resistance.

EXAMPLE 7 A sample of the resin of Example 3 after aging for more than one year at 25 C. is diluted to a concentration of 6.6% total solids. After treating the cotton percale and rayon gabardine samples therewith, it is found that the cotton has a wrinkle recovery of 252, and the hand of the rayon is only slightly firmer than the finished rayon of Example 6.

EXAMPLE J A pad bath is prepared by diluting a regular commercial sample of DMEU resin to 6.0% in a bath containing 0.36% mixed isopropanolamines hydrochlorides solids. Cotton finished with this mixture is determined to have a wrinkle recovery of 259 and rayon gabardine has a soft resilient hand.

EXAMPLE K A discolored sample of a mixture according to Example G is diluted to a total solids content of 6.3% after aging for over one year. The hand of a rayon fabric treated with this mixture is equivalent to that of Example I, but the wrinkle recovery of cotton fabric is only 211.

EXAMPLE 8 An x 80 cotton percale is padded through an aqueous pad bath of pH 8.2 containing a solution of 8% DMEU resin and 1% magnesium chloride with the pad rolls adjusted for-a 100% wet pickup. The impregnated fabric is thoroughly dried at 225 F. and then stored for one month. At the end of this time, the impregnated but uncured material is sprayed lightly to bring the moisture content of the material up to about 10% by weight. A sample of the impregnated fabric is cut off and soaked in a small quantity of water to extract the uncured finish therefrom. The pH of this aqueous extract is found to be slightly above 7 indicating that the uncured fabric is substantially neutral rather than acidic in nature. Next, the moistened material is passed through a pleating machine. After pleating, it is placed in an oven maintained at 325 F. for 1.5 minutes in order to insure that curing is complete. The material is found to have an excellent resilient hand and a permanent pleat which is extremely resistant to mussing, shrinkage and wrinkling. Upon repeating the operation with no appreciable lapse between the drying step and the pleating, a fabric is obtained with a finish equal in all respects to that of the first sample. pleated and cured materials is the same indicating that storing the uncured impregnated fabric resulted in no tendering.

What we claim is:

1. A composition of matter which comprises a stable, aqueous solution for treating textile materials'having a pH between 7.0 and 10.5, consisting essentially of magnesium chloride as the sole catalytic component and a small amount of a compatible alkaline material corresponding to a content of magnesium oxide up to about 1%, based on the total weight of anhydrous magnesium chloride, and from between 1 and about by weight of an agent selected from the group consisting of methylated methylol urea, partially polymerized methylated methylol urea, methylated and unmethylated methylol ethylene ureas and methylated and unmethylated methylol 1,2-propylene ureas, said magnesium chloride being present in said solution in an amount of from between about 2 and 25%, based on the weight of the agent solids.

2. A composition according to claim 1 comprising a pre-mixed finishing composition containing between about 60 and about 90% by weight of agent solids.

3. A composition according to claim 1 comprising a pad bath containing between about 2.5 and about 30% by weight of agent solids.

4. A composition according to claim 1 in which the agent is methylated methylol urea.

5. A composition according to claim 1 in which the agent is partially polymerized methylated methylol urea.

6. A composition according to claim 1 in which the agent is methylol ethylene urea.

7. A process which comprises impregnating a textile material with a stable, aqueous solution having a pH between 7 and 10.5, consisting essentially of magnesium chloride as the sole catalytic component and a small amount of a compatible alkaline material suflicient to produce such alkalinity corresponding to a content up to about 1% of magnesium oxide, based on the total weight The tensile strength of both I of the textile material, and curing the material by exposure to a temperature above 275 C. and below the point at which degradation of the textile material commences, for a period sufficient to convert the agent to the Water-insoluble state, whereby a finish resistant to wrinkling and shrinkage is imparted to the textile material.

8. A process according to claim 7 in which a fabric containing cellulosic fibers is treated with methylated methylol urea.

9. A process according to claim 7 in which a fabric containing cellulosic fibers is treated with partially polymerized methylated methylol urea.

10. A process according to claim 7 in which a fabric containing cellulosic fibers is treated with methylol ethylene urea.

11. A process which comprises impregnating textile material with a stable, aqueous solution having a pH between 7 and 10.5, and consisting essentially of between 2.5 and about 30% by weight of an agent selected from compatible alkaline material sufiicient to provide such alkalinity and corresponding to an amount up to about 1% of magnesium oxide, based on the total weight of anhydrous magnesium chloride, in sufficient amount to deposit thereon between about 20 and 25% of said agent, based on the weight of the dried textile material, drying the impregnated textile material at least partially, pressing the impregnated material more than 24 hours after the impregnating operation and while the moisture content is between about 5 and 20%, based on the weight of the dried textile material, and curing the material by exposure to a temperature of above about 275 F. and below the temperature at which degradation of the textile material commences for a period sufficient to convert the agent to the water-insoluble state, whereby a material of sub stantially permanent wrinkle resistance and shrinkage resistance is obtained. 3

References Cited in the file of this patent UNITED STATES PATENTS l 2,254,001 Conaway Aug. 26, 1941 2,373,136 Hoover Apr. 10, 1945 2,653,921 Sulzer Sept. 29, 1953 2,661,312 Richardson Dec. 1, 1953 2,709,141 Burks May 24, 1955

Claims (1)

11. A PROCESS WHICH COMPRISES IMPREGNATING TEXTILE MATERIAL WITH A STABLE, AQUEOUS SOLUTION HAVING A PH BETWEEN 7 AND 10.5, AND CONSISTING ESSENTIALLY OF BETWEEN 2.5 AND ABOUT 30% BY WEIGHT OF AN AGENT SELECTED FROM THE GROUP CONSISTING OF METHYLATED METHYLOL UREA, PARTIALLY POLYMERIZED METHYLATED METHYLOL UREA, METHYLATED AND UNMETHYLATED METHYLOL ETHYLENE UREAS AND METHYLATED AND UNMETHYLATED METHYLOL 1,2-PROPYLENE UREAS, AND A QUANTITY OF MAGNESIUM CHOORIDE AS THE SOLE CATALYSTIC COMPONENT, AMOUNTING TO BETWEEN ABOUT 2 AND ABOUT 25% OF THE WEIGHT OF SAID AGENT, AND A SMALL AMOUNT OF A COMPATIBLE ALKALINE MTERIAL SUFFICIENT TO PROVIDE SUCH ALKALINITY AND CORRESPONDING TO AN AMOUNT UP TO ABOUT 1% OF MAGNESIUM OXIDE, BASED ON THE TOTAL WEIGHT OF ANHYDROUS MAGNESIUM CHLORIDE, IN SUFFICIENT AMOUNT TO DEPOSIT THEREON BETWEEN ABOUT 20 AND 25% OF SAID AGENT, BASED ON THE WEIGHT OF THE DRIED TEXTILE MATERIAL, DRYING THE IMPREGNATED TEXTILE MATERIAL AT LEAST PARTIALLY, PRESSING THE IMPREGNATED MATERIAL MORE THAN 24 HOURS AFTER THE IMPREGNATING OPERATION AND WHILE THE MOISTURE CONTENT IS BETWEEN ABOUT 5 AND 20%, BASED ON TEH WEIGHT OF THE DRIED TEXTILE MATERIAL, AND CURING THE MATERIAL BY EXPOSURE TO A TEMPERATURE OF ABOVE ABOUT 275*F. AND BELOW THE TEMPERATURE AT WHICH DEGRADATION OF THE TEXTILE MATERIAL COMMENCES FOR A PERIOD SUFFICIE%NT TO CONVERT THE AGENT TO THE WATER-INSOLUBLE STATE, WHEREBY A MATERIAL OF SUBSTANTIALLY PERMANENT WRINKLE RESISTANCE AND SHRINKAGE RESISTANCE IS OBTAINED.