US3521995A

US3521995A - Tensile properties of cross-linked woven cellulosic fabrics

Info

Publication number: US3521995A
Application number: US483043A
Authority: US
Inventors: Joseph Harold Smith
Original assignee: Johnson and Johnson
Current assignee: Johnson and Johnson
Priority date: 1965-08-27
Filing date: 1965-08-27
Publication date: 1970-07-28
Anticipated expiration: 1987-07-28
Also published as: CH1230566D

Description

July 28, 1970 J; H. SMITH 3,521,995

TENSILE PROPERTIES OF CROSS-LINKED WOVEN CELLULOSIC FABRICS Filed Aug. 27, 1965 2 Sheets-Sheet l Tlcl.

INVENTOR. foffp/ ,4449010 AW/r/,f

ATTORNEY J. H. SMITH July 28, 1970 TENSILE PROPERTIES OF CROSS-LINKED WOVEN CELLULOSIC FABRICS Filed Aug. 27, 1965 2 Sheets-Sheet 2,

INVENTOR. ,4f/ 7040 ,6314/ rf/ ATTORNEY United States Patent O 3,521,995 TENSILE PROPERTIES OF CROSS-LINKED WOVEN CELLULOSIC FABRICS Joseph Harold Smith, Amherst, Mass., assignor to Johnson &'Johnson, a corporation of New Jersey Filed Aug. 27, 1965, Ser. No. 483,043 Int. Cl. D06m 13/14 U.S. Cl. 8-116.3 3 Claims ABSTRACT OF THE DISCLOSURE A method of improving the tensile strength of crosslinked cellulose fabrics by treating the fabric with a swelling agent and applying tension in the filling direction of the fabric and removing the swelling agent from the fabric while under tension. The fabric is then dried and treated with a cross-linking agent to cross-link the cellulose.

This invention relates to improved methods for crosslinking woven cellulosic fabrics, and more particularly to an improved method for cross-linking cellulosic fabrics which have initially been treated with a swelling agent for cellulose so that the resultant fabric retains a greater percentage of its original tensile strength and tear strength.

In recent years wash and wear goods, especially resintreated cellulosic fabrics, have gained in importance in the apparel industry. Generally these fabrics are made by treating the base cellulosic fabric with thermosetting resins or other types of cross-linking reactants to cross-link the hydroxyl groups of the cellulose and give the fabric dimensional stability, crease-resistance, etc. The greatest problem involved in this type of treatment is the losses which occur in the tensile properties of the fabric, especially the tensile strength and especially in the filling direction of the fabric. This is also true of fabrics which have first been treated with a swelling agent to improve their luster, sheen and dyeability.

I have discovered a method for making cross-linked woven cellulosic fabrics which have been treated with a swelling agent which retain a greater percentage of their original tensile strength, even up to 80 to 90 percent of their original tensile strength and which have improved tear strengths over standard cross-linked fabrics.

lIn accordance with my improved method, fabrics may be treated by my method and stored and later treated with a cross-linking agent and still have improved tensile properties.

In accordance with the present invention, woven cellulosic fabrics are treated with an agent to swell the cellulose. The fabrics are placed under tension in the filling direction and while under tension, the swelling agent is removed usually by washing the fabric with water. The swollen cellulosic fabric is dried. The fabric is further treated with a cross-linking agent by impregnating it with such a resin, drying the fabric and curing it to react the cross-linking agent with the cellulose. The resultant fabric retains a greater portion of its original tensile strength than does a similar fabric treated in a similar manner but with no tension applied in the filling-wise direction. In the preferred embodiment of the present invention, woven cotton fabrics are treated with caustic solutions of the mercerizing type to mercerize the fabric. Tension of at least .03 pound per thread is applied in the filling-wise direction and preferably from about 0.05 to 0.2 pound per thread tension is applied, and the fabric washed with water to remove the caustic. The washed fabric is dried and is either immediately or after a period of time impregnated with any of the known thermosetting resins or similar resins for wash and wear treatment. The impregnated ice fabric is dried and cured to react the resin with the cellulose.

The invention will be more fully understood from the description which follows taken in conjunction with the accompanying drawings.

In the drawings:

FIG. l is a simplified diagrammatic process flow sheet of the method of the present invention;

FIG. 2 is a schematic side view of apparatus for carrying the method of the present invention into operation; and

FIG. 3 is a diagrammatic view in plan of apparatus for carrying out the method of the present invention.

Referring to FIG. l of the drawings, the first step in the method of the present invention is to treat standard woven cellulosic fabrics made from either cotton yarns, rayon yarns, mixed yarns, i.e., blends of cellulosic fibers and other fibers, etc., with a swelling agent for the cellulose (Box 10). Suitable swelling agents are amines, sodium hydroxide, potassium hydroxide, zinc chloride, quarternary ammonium bases, etc. It is preferred that the fabric be treated so as to mercerize the fabric, that is, by treating the fabric with from about 2O to 30 percent caustic for a period of time from about 30 seconds to 8 minutes at a temperature from about 65 F. to 105 F. The swollen fabric is then washed, preferably with water, to remove the swelling agent (BOX 11). If desired, this may take a number of steps and in some instances dilute acid may be used to neutralize the caustic or the swelling agent used. It it essential to the present invention that when the swelling agent is being removed that tension be applied to the fabric in the filling direction. This tension may vary from about .03 pound per thread to a tension just below the rupture point of the threads. It is preferred that this tension be applied for a sustained period of time of at least 10 seconds. The fabric washed under tension is dried to remove the water (BOX 12). The fabric may be dried at various temperatures, for various times of from about F. to 250 F. for times of from about 1 minute to 4 minutes.

The fabric may be stored in this condition for considerable lengths of time or it may be used immediately dependent on what is desired. The mercerized or swollen and dried fabricis impregnated with an agent which will cross-link the cellulose (Box 13). Suitable cross-linking agents, either acid or base catalyzed, are the thermosetting resins, such as the urea formaldehydes, melamine formaldehydes, sulfones, etc. Generally a solution, preferably an aqueous solution, of the cross-linking agent is padded on the fabric so the fabric picks up from about l percent to about 10 percent by weight of the fabric. A catalyst may also be applied to aid in the cross-linking reaction. The impregnated fabric is dried to remove the water at temperatures of from about 100 F. to 250 F. for periods of time from l minute to 5 minutes (Box 14). The dried fabric with the cross-linking agent thereon is then heated at an elevated temperature of from about 325 F. to 400 F. to react the cross-linking agent with the cellulose and cross-link the cellulose (Box 15).

Referring to FIGS. 2 and 3 of the drawings, there is shown the preferred method for carrying the present invention into practice. A roll 20 of woven cellulosic fabric F is passed through a bath 21 of sodium hydroxide 22. The fabric is maintained in this bath for a period of time by passing it over rollers 23 so that it has an immersion time of from about 30 seconds to about 8 minutes. Upon being removed from this bath, the fabric is placed on a tenter frame 24. The tenter frame comprises a pair of diverging endless chains which have clips 25 to grip the fabric. The fabric upon leaving the bath is clipped at each edge and as these chains diverge the fabric is placed under tension in the filling-Wise direction. While under this filling-wise tension, the fabric is Washed by spraying it with water through the nozzles 26. This washing removes the caustic. The fabric is then dried by passing it under the heating oven 27 or over a set of dry cans if desired. The dried fabric is then passed through a padder comprising a bath 28 containing a solution of the cross-linking reagent 29. In the bath are a pair of rolls 30, and as the fabric passes through the nip of these rolls it is impregnated with the cross-linking agent. Upon leaving this impregnating bath, the fabric is placed on a permeable conveyor 3].. It is passed under radiant heaters 32 to remove the water and dry the fabric, and passed through an oven 33 to cure the fabric, that is react the cross-linking agent with the cellulose. The resultant fabric 34 is wound up in accordance with standard procedures.

The invention will be further illustrated in greater detail by the following specific examples. It is to be understood, however, that although these examples may describe in particular detail some of the more specific features of the invention, they are given primarily for purposes of illustration and the invention in its broader aspects is not to be considered as limited thereto.

EXAMPLE I An all cotton fabric having 85 warp yarns per inch and 80 fill yarns per inch is slack mercerized by passing it through a solution of 22 percent caustic at a temperature of 75 F. for a period of time of 4 minutes. The fabric is washed with water and dried at a temperature of 250 F. This fabric is treated with an aqueous solution of 17 percent urea formaldehyde resin sold by American Cyanamid Co. under the trade name Aerotex Resin 52. and 1.7 percent of an amine hydrochloride catalyst sold by the Crown Chemical Co. under the tradename Catalyst CC. The fabric is dried at 250 F. for 2 minutes and cured to react the cross-linking agent with the cellulose at 325 F. for a period of 2 minutes. Absolutely no tension is applied in the filling direction of the fabric during this treatment. The resultant fabric has a tensile strength in the filling direction of .180 pound per thread or 36 percent of its original filling tensile strength. The tear strength of the fabric in the filling direction is .71 pound.

EXAMPLE II The fabric as described in Example I is treated as described in Example I with the exception that tension is applied in the filling direction of the fabric in the amount of .05 pound per filling thread, While the caustic is being washed from the fabric. The resultant fabric has a tensile strength in the filling direction of .274 pound per thread or 55 percent of its original tensile. It has a tear strength in the filling direction of .92 pound.

EXAMPLE III The fabric as described in Example I is treated as described in Example I with the exception that 0.10 pound per thread of tension is applied in the filling direction of the fabric, While the caustic is being washed from the fabric. The resultant fabric has a tensile strength in the filling direction of .300 which. is 60 percent of its original tensile, and a tear strength in the filling direction of .85 pound.

EXAMPLE IV An all cotton print cloth, not mercerized, which is 381/2 inches wide and containing 64 warp yarns per inch and 56 fill yarns per inch is padded at a 38-inch width with an aqueous solution of percent urea-formaldehyde resin sold by American Cyanamid Co. under the trade name Aerotex Resin 52 and 1.5 percent of an ammonium hydrochloride catalyst sold by Crown Chemical Co. under the trade name Catalyst CC. The fabric picks up 5 percent by weight of resin. The fabric is dried at the 38- inch width at 250 F. and cured to cross-link the cotton with the resin at 325 F. The resultant fabric has a tensile strength in the filling direction of .261 pound per thread or 61 percent of its original tensile strength and a tear strength in the filling direction of 1.13 pounds.

EXAMPLE V A similar piece of fabric as that described in Example IV is treated as described in Example IV except that prior to resin threatment it is mercerized in 22 percent sodium hydroxide for 4 minutes at 75 F., washed with water while tension of 0.091 pound per thread is applied in the filling direction and dried at 250 F. for 2 minutes. The resultant fabric after resin treatment as described in Example IV has a tensile strength in the filling direction of .284 pound per thread or 99 percent of its original tensile strength and a tear strength in the filling direction of 2.26 pounds.

Although several specific examples of the inventive concept have been described, the same should not be construed as limited thereby nor to the specific features mentioned therein but to include various other equivalent features set forth in the claims appended hereto. It is understood that any suitable changes, modifications and variations may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. A method of improving the tensile strength of a cross-linked, woven cotton fabric comprising: treating a woven cotton lfabric with a solution of from about 20 percent to about 30 percent sodium hydroxide at a temperature of from about 65 F. to 105 F. for a period of time of from about 1 minute to 4 minutes to cause the cotton to swell, applying at least .03 pound per thread of tension in the filling direction to said swollen fabric, while said fabric is under tension washing the fabric with water to remove the sodium hydroxide, heating the fabric to a temperature of 'from about 100 F. to about 250 F. to remove the water, impregnating the dried fabric with from about l percent to about 10 percent by weight of the fabric of a cross-linking agent for cellulose, selected from the class consisting of urea-formaldehyde resins, melamine-formaldehyde resins, and sulfones, heating the fabric to a temperature of from about 100 F. to about 250 F. and treating the fabric at a temperature of from about 325 F. to about 400 F. to react said cross-linking agent with the cotton.

2. A method of improving the tensile strength of a cross-linked, woven cotton fabric comprising: treating a woven cotton fabric with a solution of from about 20 percent to about 30 percent sodium hydroxide at a temperature of from about 65 F. to 105 F. for a period of time of from about 1 minute to 4 minutes to cause the cotton to swell, applying at least .03 pound per thread of tension in the filling direction to said swollen fabric, while said fabric is under tension washing the fabric with water to remove the sodium hydroxide, heating the fabric to a temperature of from about 100 F. to about 250 F to remove the Water, impregnating the dried fabric with from about 1 percent to about 10 percent by weight of the fabric of a melamine-formaldehyde resin, heating the fabric to a temperature of from about 100 F. to about 250 F. and treatin-g the fabric at a temperature of from about 325 F. to about 400 F. to react said melamineformaldehyde resin with the cotton.

3. A method of improving the tensile strength of a cross-linked, woven cotton fabric comprising: treating a Woven cotton fabric with a solution of from about 20 percent to about 30 percent sodium hydroxide at a temperature of from about 65 F. to 105 F. for a period of time of from about 1 minute to 4 minutes to cause the cotton to swell, applying at least .03 pound per thread of tension in the filling direction to said swollen fabric, while said fabric is under tension washing the fabric with Water to remove the sodium hydroxide, heating the fabric to a temperature of from about 100 F. to about 250 F. to remove the water, impregnating the dried fabric with from about 1 percent to about 10 percent by weight of the fabric of a urea-formaldehyde resin, heating the fabric to a temperature of from about 100 F. to about 250 F. and treating the fabric at a temperature of from about 325 F. to about 400 F. to react the urea-formaldehyde resin with cotton.

References Cited UNITED STATES PATENTS 3,145,132 8/1964 Seltzer 8-120 XR 6 OTHER REFERENCES Tripp et al.: Some Relationships Between Supermolecular Structure, Etc., Textile Research Journal, pp. 404-416.

S. P. Hersh et al.: Eiect of Tension on the Properties of Resin-Treated Cotton Fabrics, Textile Research Journal (1962, April) pp. 271-284.

JOHN DAVID WELSH, Primary Examiner U.S. Cl. X.R.