US2622995A - Process for resin impregnating cellulosic fabrics - Google Patents

Description

Patented Dec. 23, 1952 UNITED STATES iPAENT OFFICE PROCESS FOR RESIN IMPREGNATING CELLULOSIC FABRICS Arnold L. Lippert and William P. Hall, Wilmington, DeL, assignors to Joseph Bancroft & Sons 00., Wilmington, Del., a corporation of This invention relates to the production of a finish on fabrics composed of cellulose and regenerated cellulose and mixtures thereof, and the primary object of the invention is to produce a durable to Water finish which has the luster hereinafter described, which is crease, spot and soilresistant, in which the individuality of the fibers and yarns is retained and the flexibility and elasticity of the fibers increased whereby the hand and drape of the fabric is superior to the original, in which the feel of the fabric is soft or mellow (not dry to the touch), in which the fabric breathes well (substantially retains its porosity), is resistant to fraying, and in which the fabric is stabilized against shrinkage, with substantial retention of the original tear strength.

As will be hereinafter set forth in detail, in the practice of our invention we employ a mechanical finishing machine and thermosetting resin-forming materials, which are applied in the water soluble state and polymerized into the water insoluble state, by heat. Such materials in relatively large concentrations have been employed to crease-proof fabrics, but the finished fabric has a dull or lack-luster appearance. Such resin-forming materials have also been used in combination with mechanical finishing to produce a fabric having a durable relatively highly glossy luster, such, for example, as a chintz fabric.

In the latter procedure, the finishing machine, whether a chasing calender, a friction calender, a smooth or flat nip calender, a schreiner calender or an embossing calender, operates with relatively high pressure, say, for example, a total pressure of 29 tons, 39 tons, 49 tons, or even higher, in some cases. In each case certain of the bowls of the calender are ordinarily heated. Due to the heat some polymerization of the resinforming material occurs in the machine. Due to the pressure and the friction (which is intentionally present in the fri tion calender and unavoidably present to some extent in the other calenders) on the fabric in passage of the fabric through the machine, the polymerized material on the fabric is caused to flow and is given a polishing action. This flowing and polishing is enhanced by the presence of water, in which connection it is the custom to only partially dry the fabric before passage through the machine, the free moisture (about or more over natural moisture content) in the fabric acting as a plasticizer of any polymerized material present. Due to the flowing and the polishing action, surface deposits of polymerized material are ironed into a continuous coating and are, as it were, shined up so that the resultant luster optically appears as a highly glossy surface luster. In the presence of such free moisture, which is also a plasticizer of cellulose, the pressure of the machine itself produces a relatively glossy finish luster which, as described, is enhanced by the flowing and polishing of surface deposits thereon. The fibers and yarns of the fabric lose in individuality and therefore suffer a substantial reduction in their flexibility and elasticity so that the finished product, after washing and drying, has been stiffened therefore has lost in hand and feel, and the crease-resistance is relatively low. The flowing and polishing also tends to fill up or close interstices.

In the production of the finish of this invention we aim on the one hand to avoid the dull lack-luster appearance obtained in crease-proofing, and on the other hand to avoid the loss in individuality, flexibility and elasticity of the fibers and reduce the closing of interstices hereinbefore described in connection with highly glossy finishes, while obtaining a luster which optically appears as an interior deep-seated luster or glow rather than a glossy surface luster and while obtaining quite substantial crease-resistance and the other properties of the finish hereinbefore first described.

Generally speaking, in the practice of our invention we first prepare a Water solution of the resin-forming materials, containing, in the case of cotton and the like, a permanent softener, and also containing a delayed action catalyst of the character to be hereinafter described, the resinforming materials constituting from 5% to 20% of the solution by weight, with the softener constituting but a very minor part, from 1% to as high as 4% by weight of the solution, and with the catalyst constituting from 3% to 5% by weight of the solid resin-forming material.

The solution is applied to the fabric in any well known Way as by impregnation, spraying, or the like, with a solution pick-up from approximately to on the weight of the fabric in its natural dry state. The fabric is now dried by running it through an atmosphere heated to from substantially 200 F. to 350 F. for a period suificiently long to remove substantially all free moisture, and then cooled as by passing over cooling cans, leaving behind substantially only the natural moisture at room temperature. In other words, a cotton fabric has a natural moisture content of from substantially 4% to substantially 6%, and rayon from substantially 7% to 9%.

The fabric is now run through the mechanical finishing machine either one or more times.

In the case of melamine-formaldehyde, ureaformaldehyde and dicyandiamide-formaldehyde resins, the delayed action catalyst is of the type which has a pH on the dried fabric of from substantially 6 pH to substantially 8 pH as determined by indicator solutions, but which will develop high acidity at the relatively elevated temperatures hereinafter to be more particularly pointed out in connection with the polymerization of the resin-forming materials to the water insoluble state. In other words, the catalyst gives for all practical purposes substantial neutrality or very low acidity on the fabric, when it has a temperature of substantially 212 F., which it will have for a few seconds at the time the free moisture has just been driven off. 'The cooling is to drop the temperature of the fabric quickly to room temperature or below (say from 60 F. to 100 F.) under which conditions the polymerization is kept at a negligible minimum. (Out of excess precaution, one may also add ammonium hydroxide to the solution to maintain neutrality during drying and until the am monia is driven off.)

The dried cooled fabric is now run through the finishing machine, which is operated at such a temperature that the temperature of the fabric will always be at or below 200 F., as will further appear. (We prefer a range of temperature of the fabric of from 100 F. to 175 F.) By maintaining the temperature of the fabric in its passage through the heated calender below 200 F., it will be seen that the catalyst will remain substantially neutral and the pH will not fall below 6 pH, at which pH the rate of polymerization will be so low that for all practical purposes little polymerization can occur during passage through the calender.

After passage through the calender, the fabric is run through an oven in which the temperature and the time of residence are sufiicient- 1y high to cause the catalyst to develop marked acidity, say a pH of 4 or 5, whereupon the catalyst will catalyze the reaction and the resin-forming material will be polymerized and become waterinsoluble. The fabric is now washed to remove unreacted materials and dried, when it is in the finished state.

It will be seen from the foregoing that at the time of the imparting of the mechanical finish there is little polymerization of the resin-forming material, the rate of polymerization being relatively exceedingly slow under the conditions; and, no substantially polymerized material being present, the luster imparted is that which is obtained essentially by the pressure and polishing action of the machine on the cellulose fibers and yarns themselves. In other words, the machine physically deforms the fibers and yarns only to the extent that they can be deformed by the machine. The luster imparted by the deformation and polishing of the fibers and yarns is thus of subdued character due to the absence of any appreciable free moisture or other plasticizer of cellulose. Since polymerization of the resin materials to the insoluble state occurs subsequently and only at a time when there is no pressure on the fabric, there is no flowing or polishing of the resin formed, in consequence of which the luster of the finished product, i. e., the washed and dried fabric, is only that which is obtained in the finishing machine on the fibers and yarns themselves, which luster is seen through the surface resin and appears not as a glossy surface luster but as an interior or deep seated luster or glow. The fibers substantially retain their original individuality instead of being imbedded in a, hard brittle resinous mass as in the case of regular highly glossy glazed chintz. This individuality, together with the increased flexibility caused by resin deposition, gives the finished fabric a hand, drape and flexibility superior to the original. The size of the interstices has been to a large extent retained and the fabric has a good porosity when compared with the original. The finished fabric has far more crease-resistance than does durable chintz, for example, and has a crease-resistance approaching that obtained in the ordinary procedures followed in producing crease-resistant fabric. The finish is durable to repeated washings and drycleanings and has the other properties hereinbefore set forth. Since the hard resinous material produced in the polymerization in the oven is formed when there is no pressure, the softener used in the case of cottons is now most effective to act, as it were, as a lubricant whereby the original tear strength is substantially retained. In this respect the fact that the catalyst becomes actively acid in the oven, also tends to the retention of tear strength. In the case of regenerated cellulose a softener is not needed to retain strength.

For thermosetting resin-forming materials we may employ any acid-catalyzable materials, such, for example, as urea-formaldehyde, thioureaformaldehyde, dicyandiamide formaldehyde, mixtures thereof, melamine-formaldehyde, mixtures of melamine and urea or thiourea dicyandiamide formaldehyde, and in fact any of the acid catalyzable resin-forming materials used in the textile art for producing crease-resistance. For the formaldehyde, glyoxal may be substituted. The resin-forming materials may be employed in the unreacted state or may be partially condensed to the so-called A stage in which they are still water soluble.

For the catalyst we prefer to use carbazide hydrochloride. This may be substituted by any of the following which are the equivalents for the carrying out of the process, namely, phenyl biguanide hydrochloride; monoguanyl urea phosphate; di-monoethanolamine hydrogen phosphate; octadecyloxymethyl pyridinium chloride; and similar products such as Catalyst AC (an organic nitrogen chloride); and for the permanent softener when used we prefer to use octadecyloxymethyl pyridinium chloride for which any of the following may be substituted as equivalents, namely, for the softener we may use the so-called substantive cation active type such as Sapamine KW (trimethyl ammoniummethyl sulfate of monostearylmetaphenylene diamine) Triton K-60 (tetra alkyl quaternary ammonium chloride), Ammonyx T (trialkylbenzyl ammonium chloride), and numerous other similar products sold under such commercial names as Soromine, a quaternary derivative of a cotton bowls, the steel bowls are heated to a temperature of from substantially 250 to 300 F. In such a calender, 15 tons pressure is applied to each. ram. Calculated on the linear basis, with .bowls 60""wide, the. pressure is onehalf ton per inch ona 60" fabric.

The fabric is given 'a number of passes, preferably "four,

through each'nip'of the 5-bowl calender, i. e.,

there will be four thicknesses or layers of the fabric in the nip between each pair of bowls at all times. Underthese conditions thetemperature of the fabric will remain well below 175 F. The number of passes may beincre'ased or decreased, so long asthe temperature achieved by the fabric is not above 175 F.

After the chasing calender the fabric is run through an oven having an atmosphere heated to a temperature of from substantially 250 F. to substantially 350 F. The timein the oven is from substantially 8 minutes to substantially 2 minutes. In the oven the resin-forming materials are ipolymerized and become "water insoluble.

In the case of "a plain or flat nip calender, with howls rotating at the same peripheral speed, the heated bowls may be safelyheated to-a temperature from 250 F. to 350-F., at-customary operating speeds which are usually in the neighborhood of 150 yards per minute. These calenders are usually of the multi-bowl type having from three to seven bowls, although two-bowl'and nine-bowl machines are known. Where there are, for example, seven or more bowls, the fabric is desirably run through only once, with the temperature of the heated bowlssu ch as 'to ensure that the fabric does not achieve a temperature in excess of 175 F. Where the number of passes is smaller, the fabric -may be run-through two or three times, providing again that'the temperature of the heated bowls is not-sufiicient to cause the fabric'to achieve a temperature above 175 F.

In the case of a schreiner or an embosser, the fabric can of course be only run through once. Here a temperature on the-heated-bowl'may be relatively somewhat higherQbut'in no case should be such as to cause the fabric to "achieves temperature of substantially bove 175 F. In such machines a temperature ashigh as 350 F. may

be safely employed at customary operating speeds, which are usually in the neighborhood of 15 yards per minute.

In the case of the 'frictionaglazer, thefabric is passed throughthenipbut onceor twiceinstead'of the three or more times employed in the production of durable-Chintz. :The heated bowl in thiscase may be operated at a'temperature of from substantially 300 :F. to'substantially 350 F. at the customaryspeedsof operation, which areusually in'the neighborhood of 30 yards per minute. In this case a lubricant is desirably present in the solution. The softeners heretofore listed are also lubricants so they may be used in the double capacity in the case of cottons. In the case of rayon, they act as lubricants. In the latter case, non-permanent softeners or lubricantscanbe used, such as sulfonated castor oil, sulfonated hydrocarbon (Avitone A) and polymerized ethylene oxide (carbowaxes) may be used, and this materialis'largely "removed during the final washing.

Example I Solid resin 5% Cotton Chasehigh pressure-low temperature Cure-short time-hi'ghtemperature Dry--high temperature 40.0 lbs. Aerotex M-3 (dimethyltrimethyl melamine-formaldehyde solid resin) 20.0 lbs. Aerotex #450 (dimethylol ureaformaldehyde resin 50% solid) 10.0 lbs. Iriton K-60 410 lbs. monoguanyl-urea phosphate -1 .0 lbpammonium hydroxide (28%) 'to neu- -tralize -Water :to make *gallons.

A cotton fabric was impregnated with the above solution and squeezed until a' solutionpick-upof 7 0% was obtained.

This cloth wasthen dried in-an atmosphere of 350 F. until -approximately-6% moisture (nat ural) remained in the fabric which was then quickly'cooled to room temperature substan- The fabric was then chase calendered in a 5-bowl machine using 50 ton total pressure and 250 F. on the steel bowls. The speed of the machine was 170 yards a minute.

The fabric was then cured in an oven for 2 minutes at 350 F. and finally washed and'dried.

The resulting fabric 'h'ada deep-seatedmellow glow' and'a soft drapery 'hand-andwas more resistant to creasing than the original fabric.

'ErampZe 'II Solid content high 20% Rayon Chaselow pressure-high temperature Curelong time-low temperature Dry-40w temperature 450.0 lbs. methylol urea-formaldehyde resin 20.0 lbs. Aerotex #801 (dimethylol ureaformaldehyde'resin 100% solid) "2510* lbs. Sapamine K. W.

20.0 lbs. catalyst 'A. C.

1.0 lb. ammonium hydroxide (28%) *to neu- 'tralize Water to make gallons.

A spun rayon fabric was impregnated with the above solution, squeezed until 80% by weight of the solution was retained by the fabric which was then dried in a drying unit operating-at a temperature of 250 F. until approximately a total of 8% moisture (natural) remained in the fabric.

It was then quickly cooled to-approximately*60 Example -I I I 1. Solid 12 2. Cotton 3. Chasemedium pressuremedium temperature 4. Cure-medium timemedium temperature 5. Dry-medium temperature 100.0 lbs. Resloom I-IP (di and trimethylol melamine-formaldehyde resin) 30.0 lbs. Ahcovel G 8.0 lbs. di-monoethanolamine hydrogen phosphate 1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100 gallons.

A cotton printed broadcloth fabric was impregnated with the above solution and squeezed to remove excess solution. It was then carefully dried in a tenter frame at 300 F. to natural moisture and then quickly cooled to substantially 70 F.

The fabric was then chase calendered by running it once through a -bowl calender operating at 30 tons and 275 F. The cloth was then cured 5 minutes at 300 F. and finally washed and dried.

A beautiful deep-seated lustrous flexible fabric was obtained with increased crease-resistance and good strength.

Example IV 1. Rayon 2. Glaze 60.0 lbs. Aerotex M3 100.0 lbs. methylol urea-formaldehyde resin 20.0 lbs. Avitone A 8.0 lbs. carbazide hydrochloride 1.0 lb. ammonium hydroxide (28%) to neutralize Water to mak 100 gallons.

A spun dyed rayon fabric, 40", 46/40, 3.50 yds./lb., was impregnated with the above solution, squeezed, dried, and cooled as described in Example III.

This fabric was glazed once by passing it through the glazing calender operating at 40 tons, 325 F. temperature and a friction ratio of 2:1.

The resulting fabric was cured 6 minutes at 290 F. and then washed and dried.

The resulting fabric had a good deep-seated luster and a linen-like flexible hand and good crease-resistance.

Ezrample V 80.0 lbs. Aerotex M-3 60.0 lbs. Aerotex #450 20.0 lbs. Avitone A 10.0 lbs. catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100 gallons.

A 45", 39/32, 2.25 yds./lb. spun rayon (75%) cotton (25%) was impregnated, squeezed, dried, and cooled as described in Example III.

The fabric was then run once through a 5-bowl chase calender at 40 tons pressure and 250 F., followed by curing 3 minutes at 275 F. This was followed by washing and drying.

The resulting fabric had a linen-like hand and appearance. In addition the fabric was very flexible and decidedly resistant to creasing.

Example VI 1. Solid 11% 2. Glaze-high pressurehigh high friction 80.0 lbs. Aerotex M-3 50.0 lbs. dicyandiamide-formaldehyde resin (50 30.0 lbs. Triton K-BO temperature 6.0 lbs. carbazide hydrochloride 1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100 gallons.

15 A printed, 39", 80/ 92, 3.50 yds./lb., cotton fabric was sized and dried and cooled in the previously described manner in Example III. It was then passed twice through a glazing calender at 50 ton total pressure at a temperature of 350 F. and

with a friction ratio of 23:1.

The fabric was then cured, washed, and dried in the usual manner.

A deep-seated lustrous, flexible, ful1 fabric of good crease-resistance was obtained.

25 Example VII 1. Solid high 20% 2. Rayon 3. Flat nip-high pressurelow temperature 4. Curemedium 5. Dry

460.0 lbs. methylol urea-formaldehyde (50%) 20.0 lbs. Rhonite #313 (dimethylol ureaformaldehyde resin 50%) 20.0 lbs. Glyoxal 20.0 lbs. catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to new tralize Water to make 150 gallons.

" A spun rayon fabric was impregnated and squeezed with the above solution and then carefully dried to natural moisture and cooled as described in Example III.

This fabric was given one run through a regular 5-bow1 fiat nip calender operating at 40 tons and 250 F. followed by curing 5 minutes at 300 F. After washing and drying, a deep-seated 10W luster crease-resistant fabric of a good full hand r was obtained.

" Example VIII 1. Cotton 2. Schreiner 80.0 lbs. Aerotex M-3 60.0 lbs. Aerotex #450 10.0 lbs. Sapamine K. W.

10.0 lbs. catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100 gallons.

Example IX 1. Cotton 2. Embossing A plain weave dyed cotton fabric was treated as described in Example VIII except that the fabric was passed through an embossing calender instead of the schreiner. The results were the same, except that there was also an embossed effect.

We claim:

1. The process of finishing fabrics of cellulose and regenerated cellulose and mixtures thereof which comprises impregnating the fabric with an aqueous solution of water-soluble acid-catalyzable thermosetting textile resins of the aldehyde type in concentration of from substantially to substantially by weight of the solution and carbazide hydrochloride as a catalyst, in minor part by weight, with a solution pick-up of from substantially 70% to substantially 90% by weight of the fabric in the dry state, drying the fabric at temperatures between about 200 F. and about 350 F. until it is substantially devoid of free moisture, the drying being at a temperature and for a time such that the pH of the dried fabric is not below 6 pH as determined by indicator solutions, promptly after such drying, cooling the fabric to substantially room temperature, passing the dried, cooled fabric through a pressure mechanical finishing calender heated to a temperature such that the fabric is heated to a temperature of between from substantially 100 F. to substantially 200 F. in its passage therethrough, and passing the fabric through an atmosphere heated to from substantially 250 F. to substantially 350 F. for a residence time of from substantially 8 minutes at the lower temperature to substantially 2 minutes at the higher temperature.

2. The process of finishing fabrics of cellulose and regenerated cellulose and mixtures thereof which comprises impregnating the fabric with an aqueous solution of water-soluble acid-catalyzab le thermosetting textile resins of the aldehyde type in concentration of from substantially 5% to substantially 20% by weight of the solution,

10 ootadecyloxymethyl pyridinium chloride as a softener and carbazide hydrochloride as a catalyst, each in minor part by weight, with a solution pick-up of from substantially to substantially by weight on the fabric in the dry state, drying the fabric at temperatures from about 200 F. to about 350 F. until it is substantially devoid of free moisture, the drying being at a temperature and for a time such that the pH of the dried fabric is not below 6 pH as determined by indicator solutions, promptly after such drying, cooling the fabric substantially to room temperature, passing the dried, cooled fabric through a pressure mechanical finishing calender heated to a temperature such that the fabric is heated to a temperature of from substantially F. to substantially 200 F. in its passage therethrough, and passing the fabric through an atmosphere heated to from substantially 250 to substantially 350 F. for a residence time of from substantially 8 minutes at the lower temperature to substantially 2 minutes at the higher temperature.

ARNOLD L. LIPPERT. WILLIAM P. HALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,049,217 Meunier July 28, 1936 2,050,156 Borghetty Aug. 4, 1936 2,121,005 Bener June 21, 1938 2,242,218 Auer May 20, 1941 2,347,024 Beer Oct. 18, 1944 2,454,391 Jones Nov. 23, 1948 OTHER REFERENCES Ellis, The Chemistry of Synthetic Resins, vol. 1, 1935, page 315.

Claims (1)

1. THE PROCESS OF FINISHING FABRICS OF CELLULOSE AND REGENERATED CELLULOSE AND MIXTURES THEREOF WHICH COMPRISES INPREGNATING THE FABRIC WITH AN AQUEOUS SOLUTION OF WATER-SOLUBLE ACID-CATALYZABLE THERMOSETTING TEXTILE RESINS OF THE ALDEHYDE TYPE IN CONCENTRATION OF FROM SUBSTANTIALLY 5% TO SUBSTANTIALLY 20% BY WEIGHT OF THE SOLUTION CARBAZIDE HYDROCHLORIDE AS A CATALYST, IN MINOR PART BY WEIGHT, WITH A SOLUTION PICK-UP OF FROM SUBSTANTIALLY 70% TO SUBSTANTIALLY 90 % BY WEIGHT OF THE FABRIC IN THE DRY STATE, DRYING THE FABRIC AT TEMPERATURES BETWEEN ABOUT 200 F. AND ABOUT 350* F. UNTIL IT IS SUBSTANTIALLY DEVOID OF FREE MOISTURE, THE DRYING BEING AT A TEMPERATURE AND FOR A TIME SUCH THAT THE PH OF THE DRIED FABRIC IS NOT BELOW 6 PH AS DETERMINED BY INDICATOR SOLUTIONS, PROMPTLY AFTER SUCH DRYING, COOLING THE FABRIC SO SUBSTANTIALLY ROOM TEMPERATURE, PASSING THE DRIED, COOLED FABRIC THROUGH A PRESSURE MECHANICAL FINISHING CALENDER HEATED TO A TEMPERATURE SUCH THAT THE FABRIC IS HEATED TO A TEMPERATURE OF BETWEEN FROM SUSTANIALLY 100* F. TO SUBSTANTIALLY 200* F. IN ITS PASSAGE THERETHROUGHT, AND PASSING THE FABRIC THROUGH AN ATMOSPHERE HEATED TO FROM SUBSTANTIALLY 250* F. TO SUBSTANITALLY 350* F. FOR A RESIDENCY TIME FROM SUBSTANTIALLY 8 MINUTES AT THE LOWER TEMPERATURE TO SUBSTANTIALLY 2 MINUTES AT THE HIGHER TEMPERATURE.