Carpet Embossing In Register With Print

Abstract

Pile fabrics prepared from nylon carpet fibers having a textured or embossed surface and a process of developing the textured effect which comprises selectively contacting the surface of said carpet with a chemical fiber shrinking agent therefore, allowing the shrinking action to occur and, thereafter, effectively removing the shrinking agent from the surface, said shrinking serving to reduce the height of the pile in the treated areas and creating said textured surface.

Description

BACKGROUND OF THE INVENTION

In the production of nylon pile fabrics, it is often desirable to emboss the surface thereof in order to provide added decorative appeal. In some instances, the embossed areas are printed with dyes to further embellish the surface design.

Embossing the pile fabrics is conventionally accomplished with a heating embossing roll or plate which has been engraved or otherwise treated to create the design desired in raised relief on the surface. A method which eliminates the use of embossing rolls has been disclosed in U.S. Pat. Nos. 2,790,255 and 2,875,504. In accordance with these patents, the pile fabric is formed from a combination of shrinkable and non-shrinkable yarns. Upon subjecting the fabric to the influence of heat, the pile formed from the shrinkable yarns contracts while the base and the non-shrinkable yarns remain intact thereby yielding a pile made up of high and low areas to give the appearance of an embossed or carved product.

A chemical embossing method is disclosed in U.S. Pat. No. 2,020,698. According to this patent, fabric having a pile of organic ester of cellulose yarn is locally treated with an alkali or alkaline salt saponifying agent in order to obtain ornamental differential effects in the treated areas. Furthermore, since the organic ester of cellulose pile yarns that have not been saponified are more difficult to change from their position, after they are once set than are the saponified organic ester of cellulose yarn, it is possible to obtain a differential lay between the saponified and unsaponified organic ester of cellulose pile yarn. Thus, the fabric, after the application of the saponifying agent, may be washed, finished and dried with the pile erect, after which the fabric may be run through water and brushed across the piece to lay the pile towards the selvage and it is then dried. This causes the saponified pile yarn to lie flat while the unsaponified yarn remains substantially erect. Upon subsequent steaming and brushing the fabric in the opposite direction, any unsaponified yarn which may have been slightly bent from the vertical by the previous brushing toward the selvage is caused to stand erect without disturbing the position of the laid or crushed saponified organic ester of cellulose pile yarn.

SUMMARY OF THE INVENTION

It is the primary object of this invention to provide a simple process for producing a nylon pile having a textured or embossed surface.

Another object is to provide such a process which is readily adaptable to standard printing equipment.

Another object is to provide a process which allows the production of pile fabric having embossed areas in register with a printed design.

A further object is to provide an embossing process which is readily adaptable to curved and irregular surfaces.

Various other objects and advantages of this invention will be apparent from the following detailed description thereof.

It has now been discovered that it is possible to produce superior nylon pile fabrics having embossed surfaces by contacting selected portions of the surfaces with a chemical embossing agent for the fibers of said pile fabric causing dimensional change by linear contraction of the treated fibers and, thereafter, effectively removing the embossing agent. The resulting product is thus depressed at the treated areas.

The embossing composition can be transparent so that the appearance of the product is not altered other than in being embossed. Alternatively, the embossing agent can be part of a dye or pigment composition used in printing the fabric so that the color appears in perfect register in the areas of embossing agent application.

The depth of the depressed areas can be controlled by varying the concentration and/or type of embossing agent. This variation in concentration can be effected by the amount of vehicle applied as well as by the strength of the embossing reagent.

Furthermore, the embossed depth can be controlled to some degree by the depth of penetration of the print paste carrying the embossing agent as well as the steamer time and steamer temperatures to which the pile fabric is subjected in order to activate the chemical embossing agents which provide the desired effect.

This discovery makes possible the production of a product having embossed surfaces which can be in complete register with a printed design. Additionally, the discovery makes possible the utilization of many types of printing apparatus for purposes of effecting embossing, thereby eliminating the need for expensive embossing equipment. Further, it allows the embossing of a surface without exerting sufficient pressure to permanently deform the pile fabric. A great number of products can be produced by the process. They can be used for floor, wall and ceiling coverings, drapery, upholstery and the like, and, in fact wherever pile fabrics are utilized. They are readily adaptable to decorating any surface on which pile fabrics can be applied. Many additional applications will occur to those skilled in the art.

This invention will be better understood from the following detailed description thereof together with the accompanying self-explanatory drawings in which:

FIG. 1 is an enlarged top view of a section of an embossed product of this invention; and,

FIG. 2 is an enlarged cross-sectional view of the same product taken through line 2--2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the production of the pile fabrics of this invention, the pile yarn employed is nylon. Synthetic fibers prepared from polyamides such as nylon are well known to those skilled in the art.

Likewise, the embossing agents which are applied to the nylon fibers in order to produce the desired effect are also known chemical compounds. For purposes of this invention, the term "embossing agent" is defined as any active chemical composition which when applied to the pile fabric produces a measurable reduction of pile height, but without significant deterioration of the nylon fibers. The exact chemical/physical mechanism by which this result is achieved is not completely understood. However, it is believed that the embossing agent may owe its effectiveness largely to its capability to function as a hydrogen bond breaker. Initially, the fibers are in a stretched and crystalline state. When the hydrogen bond is broken between the polymer chains, the fibers relax and shrink. Regardless of the mechanism, the overall effect produced is one of dimensional change, the most desirable effect, involving linear contraction of the fiber.

In order to be applicable for the novel process of this invention, the embossing agent should provide a reduction of the pile height through a shrinkage reaction, should not adversely affect the printing means, e.g., print screens, and should be capable of being substantially removed or inactivated subsequent to the embossing action. Other characteristics of the embossing agent which are desirable, though not essential, include compatibility with dye print pastes, capability of being regulated by factors of time, temperature and concentration, i.e., susceptibility to activation by a conventional steaming operation and exhibiting no residual embossing activity. Needless to say, minor adjustments in the nature of the components and process conditions, and/or the embossing apparatus can be employed to overcome the absence of certain of these desired characteristics.

The embossing agent for the nylon fibers is applied to one surface of the pile fabric in any desired design, whether it be random or predetermined. One of the easiest methods of applying the agent is by utilizing conventional printing technique such as silk screen or block printing. The embossing agent can be applied as a concentrate, as part of a transparent vehicle, or as part of a dye composition utilized for pile fabric printing. The nature of the embossing agent dictates the nature of the vehicle to be utilized. Among such applicable vehicles are included: water, and alcohols such as methanol and isopropanol. Often thickeners, e.g., gums, and cellulose derivatives, are included in order to obtain viscosity characteristics demanded in print technology and to enable the embossing agent to adhere to and operate on the synthetic fiber and to hold the printed pattern.

In those instances where it is desired to achieve a single- or multi-colored printed decoration with a distinct color for the embossed areas, the embossing agent can be incorporated into a particular dye or pigment composition. The dye or pigment will generally be in the form of a print paste ink to which the appropriate amount of agent is added. It is to be noted that in preparing these modified dye compositions, the pH levels, viscosities, and dye concentrations which are essential to an effficient dyeing operation must also be controlled. The resultant effect is an embossed design in register with the printed pattern. If different depths of embossing are sought, they are achieved by use of different concentrations of agent in the areas calling for such different depths.

Generally, it is desirable that the embossing agent be soluble or in solution in the solvent medium from which it is applied to the selected areas of the fabric. However, if the agent is not soluble it should be in the composition in a form at least sufficiently finely divided to pass through the print screen, that is, it should be present in a micro pulverized form which indicates particle diameter of the order of 100 microns or smaller. That is, it must not only pass through a screen but it must pass through freely, dispersed through the dye paste throughout the printing operation. The purpose of this, of course, is to make sure that the agent becomes uniformly dispersed over the fiber in the print process so that the shrinking effect will be uniformly developed in the fiber.

As previously indicated, the preferred embossing agent is one which is dormant during the successive printing operations but then is activated by the elevated temperature of a steam chamber usually utilized to fix the dye onto the fibers. The embossing agents of this invention which can function in this manner on nylon and produce shrinkage of the nylon fibers without physical deterioration comprise an azole such as benzotriazole in combination with an acid such as acetic acid. When this combination of chemicals is added to the dye print paste in the proper concentrations and proportions, nylon carpet pile can be embossed deeply without significant fiber deterioration exactly in register with a printed design by shrinking the nylon fibers. While the preferred azole is benzotriazole, other azoles containing one to four nitrogens in the aromatic, heterocyclic, 5-membered ring may be used. Examples are pyrrole, 5-chloroindazole, 5-chlorobenzotriazole, 5-amino tetrazole monohydrate and benzothiazole. While acetic acid is preferred, other acids may be used such as formic, phosphoric, citric, hydroxyacetic, oxalic, propionic, maleic, hydrochloric and sulfuric. At the individual concentrations employed in this process benzotriazole or its substituted products and analogues alone, or the acid alone, are not generally useful because of such factors as insolubility at room temperature, ineffectiveness, volatility, toxicity, destructiveness, cost.

The advantages of this type of chemical embossing agent are that there is no need for rigid time control in the process and there is minimal concern regarding excessive uncontrollable embossing because other factors can be changed. Thus, the degree of diminution of the pile height can be controlled by adjusting the amount of dye paste applied, the concentration of embossing agent in the dye paste and the temperature and time of exposure in the steam chamber. All these factors can be adjusted according to properties of the nylon fiber comprising the pile fabric. While the depth of embossings will be determined by the practitioner in accordance with the type of embossed product being prepared, reduction in pile height will generally not exceed more than about 50%, this value being indicative of excellent embossing without exposing the backing materials.

Embossing can be achieved, if desired, by subjecting the treated fibers to heat for short periods of time. Thus, the treated surfaces may be subjected to the radiation from the bank of infrared lamps, particularly where the embossing agent is not part of a dye print paste. Additionally, even where the steaming operation is not essential to activate the embossing agent, such steaming may have the effect of increasing the penetration of the embossing agent and increasing the speed of its action on the fibers.

A critical step of the novel process of this invention involves terminating the embossing action and/or effective substantial removal of the embossing agent from the pile fabric. It may be necessary to achieve complete elimination of all residues of the embossing process which may contribute undesirable properties to the finished fabric, such as odor, toxicity and color and texture change. Needless to say, any termination or quenching technique resorted to will depend on the particular embossing composition employed. The most useful technique for removing residues of the embossing process is by thoroughly washing the fabric with water and detergents. In those instances where the embossing agent is part of a dye or pigment composition, the washing cycle is utilized to remove excess dye of pigment serves also to remove traces of the agent. Where an acidic embossing agent is utilized, e.g., formic acid on nylon, it is possible to halt the embossing action more rapidly by rinsing with an aqueous ammonia or mildly alkaline solution. This neutralization of the acid serves to insure the total removal thereof.

Other techniques for terminating the embossing action and/or removing the embossing agent include evaporation and dry cleaning. Thus, if the agent is volatile, steaming of the treated pile fabric will serve to evaporate a large portion of the embossing agent content. Where rinsing techniques are not effective, it may be necessary to resort to a dry cleaning procedure to remove the embossing residues.

The invention has particular application to tufted carpet which are to have a printed decoration applied thereon. Unusual design effects can also be obtained when the pile fabric is printed with a multi-colored design wherein one or more of the dye compositions contain the appropriate embossing agent. The process of printing such carpets includes the steps of passing carpets, tufted or unpigmented or colored fibers, into a screen printing apparatus whereby a design is printed on the surface of the carpet. Each screen applies a separate color to make up the final design. The embossing agent can be added to one or more of these printing stations by addition to the dye composition, or it can be applied by a separate station in a transparent vehicle. The fabric is then passed into a steaming chamber to set the dyes and cause embossing and then to a washing cycle which serves to remove excess dye as well as to terminate the embossing action and/or remove the embossing components.

Accordingly, in the embossing of carpet or textured pile fabric, and for all practical purposes we are discussing the embossing of carpeting, it is important that any color design on the surface of the carpet which is related to the embossing be in accurate register with the embossing. Since we are concerned only with chemical embossing the problem is then one of inducing the differential fiber length between the embossed colored areas and unembossed areas and, while it is possible to induce shrinkage of synthetic nylon fibers, it is necessary for preparation of the carpet that the film shrinkage be induced with no significant deterioration of what is left. Thus, if the operation of embossing involves true shrinkage the shrunk fabric fiber should have a texture approximating that of the original.

Many azoles are largely insoluble in water at room temperature. Some become solubilized, however, at room temperature in an acid solution such as acetic acid. Thus, for example, while the preferred benzotriazole is only slightly soluble in water at room temperature (about 2% at 77.degree.F), up to at least 50% benzotriazole goes into solution in a 40% solution of glacial acetic acid in water at room temperature (77.degree.F) and remains in solution. Because of this, we are able to meet an important practical requirement that the embossing agent be preferably soluble or at least finely dispersable in the dye print paste at room temperature. Complete solubility or dispersability to an extremely finely divided condition is required so that the individual particles contained in the printing paste can pass through the carpet printing screen and reach a maximum area of the nylon fiber to develop the desired effect. Preferably the solubilizing medium should be water although other solvents may be employed. However, the partial or total replacement of water by another solvent may cause a reduction in the extent of carpet embossment by the benzotriazole/acid embossing agent.

A number of factors appear to influence the effectiveness of azoles as embossing agents for nylon carpet. These include the location and number of nitrogen atoms in the azole ring, the presence of the active hydrogen atom on the azole ring nitrogen, the type and location of substituent groups, the presence of heteroatoms such as oxygen and sulfur in the azole ring, the type and concentration of acid employed, the ratio of azole to acid and the extent of solubility of the azole in acid solution at room temperature.

As noted before, benzotriazole is the preferred azole. In addition to its ready solubility in acid solution at room temperature, benzotriazole is preferred because of its manageability (safe margin between fiber shrinkage and fiber destruction), effectiveness as an embossing agent, nonoffensive odor, lack of volatility, ease of handling and relative nontoxicity.

Suitable combinations of benzotriazole and acetic acid are selected from within approximately the following broad range of concentrations for each component as to obtain nylon carpet embossment to the desired depth. These ranges represent parts per hundred of the total print paste.

Benzotriazole 5-50

Galcial Acetic Acid 60-15

Preferably, however, the proportions of benzotriazole and acetic acid will be selected from within approximately the following narrower ranges.

Benzotriazole 15-30

Glacial Acetic Acid 45-25

Within these concentration ranges, the individual components used alone are unsuitable for nylon carpet embossment. At the concentration needed for carpet embossment, benzotriazole is insoluble in water at room temperature and the destructive effect of benzotriazole on nylon fibers is difficult to control, while the concentration of acetic acid alone needed to emboss carpet will generally exceed 60%. The combination of benzotriazole and acetic acid provides an easily manageable and effective embossing agent.

A procedure of trial and error is required in order to arrive at the best proportions of benzotriazole and acetic acid or other azoles and other acids needed to achieve a desired depth of embossment without deterioration of the nylon carpet pile. It is, of course, important that the nylon fibers remain physically fibers and that the shrunk carpet pile retain its original physical character as well as acceptable appearance and feel. Generally, however, it will be found that the sum of the concentration of benzotriazole and the concentration of acetic acid in the print paste will fall within the limits of 45-65%. Whenever maximum carpet embossment is obtained (that depth just short of fiber deterioration, unacceptable hardness or the like) any reformulation which calls for increasing either component should be accompanied by a reduction in the concentration of the other component, otherwise fiber deterioration will occur.

The concentration range within which benzotriazole and acetic acid may be selected does not necessarily hold true for other acids and other azoles. Suitable concentrations and proportions must be determined by trial and error.

Depth of embossment as well as the deteriorating effect of the embossing agent upon the nylon carpet fibers is not only related to the strength of the embossing agent, but is also related to the distribution and penetration of the embossing agent into the nylon carpet pile. Therefore, print paste viscosity is important in influencing the depth of embossing as well as the embossed pile character since it regulates the penetration of the dye print paste containing the embossing agent into the carpet pile as well as the quantity of embossing agent deposited. Both penetration and amount of embossing agent applied can also be regulated by the number of squeegee roller strokes. Other factors effecting both shrinkage and attack of nylon fibers are steamer time and temperature. Too long a steamer time or too high a temperature generally aggravate nylon fiber deterioration. Generally, it appears that the maximum reduction in nylon carpet pile height will not exceed much more than about 50% without fiber deterioration reflected in unacceptable pile hardness, harshness, weakness, fusion, and the like. Lesser embossed depths are of course obtained by altering the proportions and/or concentrations of the components of the embossing agent.

In order to practically evaluate the utility of a particular chemical or combination of chemicals as an embossing agent for nylon carpet, the chemical system is incorporated in the dye printing paste and applied to a section of the nylon carpet by means of a screen printing technique so as to simulate plant production procedure as closely as possible. The treated carpet sample is steamed about 15 minutes at 215.degree.-200.degree.F, thoroughly rinsed with water and dried at 180.degree.F. Then the embossed area is rubbed briskly with the finger tips or for example by means of a wooden knife handle to loosen and separate tufts. In the plant, this is accomplished by brushing. The depth of embossment is then measured and observations made regarding the character of the embossed nylon, e.g., strength, brittleness, softness, definition, color. Measurement of the pile height at the embossed and unembossed areas is made by means of a thin, half-inch wide steel ruler marked off in 1/64 inch intervals. But any method of measurement is useful so long as it is standardized from operation to operation and is reproducible to about 1/64 inch.

However, for the preliminary determination of whether or not a chemical composition is capable of shrinking nylon fibers and for thus determining its potential suitability as a chemical embossing agent for nylon carpet, we have devised a simpler, less time consuming beaker test procedure. Using this test, the percent shrinkage and the percent weight loss experienced by a 50 centimeter loop of nylon carpet filament or carpet yarn is determined by immersing the yarn loop in an aqueous solution or dispersion of the test chemical for 15 minutes at 215.degree.F (102.degree.C). This test affords a simple way of determining what effect a selected chemical will have on the nylon fibers and provides a means of predicting whether or not a chemical will function as an embossing agent for nylon carpet. Also, the test provides a method for determining such effects as chemical concentration, temperature, time, print paste additives, solvents other than water, nylon type and construction and the like. Details of the test procedure are outlined as follows in Table I.

TABLE I

BEAKER TEST PROCEDURE

1. prepare a solution or dispersion of the chemicals to be tested in water.* If heated, cool to room temperature. Weigh 30 grams into a 32 .times. 200 mm test tube.

2. Place test tube in preheated Silicone bath and heat contents of test tube to the desired temperature (usually 215.degree.F (102.degree.C)).

3. cut approximately 1 meter length of nylon yarn or filament which has been held at 73.degree.F and 50% relative humidity for 24 hours and tie in a single loop.

4. Hang the loop under 50 gram load for 30 seconds and measure the length of the loop to 0.1 cm.

5. Weigh loop to nearest 1/10 mg.

6. Immerse nylon loop in hot chemical solution, agitate gently and observe any change in character of the nylon fibers. Generally hold for 15 minutes or less.

7. Remove the nylon loop and wash thoroughly in copious amounts of water. Blot and dry to constant weight at 73.degree.F and 50% relative humidity.

8. Measure length of nylon loop as in 4.**

9. Determine weight of nylon loop as in 5.

10. Calculate % shrinkage and % weight loss.

With the information thus obtained concerning the extent of shrinkage, deterioration or destruction of the nylon fibers, it then becomes possible to predict whether or not the chemical composition has any potential as an embossing agent, and eventually proceed to the formulation of a printing paste which includes the shrinking material. Experience has shown, however, that while such test results prove that the chemical agent will shrink nylon fiber and thus has an embossing capability for nylon carpet, these results tell us only roughly what concentration of the chemical agent is required to emboss nylon carpet. Nor do we know the exact extent of fiber deterioration that will be experienced on the nylon carpet. Generally, the following relationship seems to exist between beaker test results and screen printing test results on nylon carpet. Beaker test shrinkage results must reach at least about 50% shrinkage in 15 minutes at 215.degree.F in order for an embossing agent to produce even trace to very weak carpet embossment. But beyond about 50% shrinkage via the beaker test, the nylon filament begins to deteriorate rapidly (test loop weakening and fragmentation). On the other hand, if appears that deeply embossed carpet can only be anticipated if the chemical shrinkage agent causes fiber destruction in the beaker within about 60 seconds. Generally, the maximum depth of embossment obtainable without causing unacceptable nylon carpet fiber deterioration is usually about 50%.

Apparently, the difference between beaker test shrinkage results obtained on a loop of nylon filament on yarn, and screen printing test results obtained on nylon carpet, occurs because the chemical is utilized much less effectively on the carpet pile than in the beaker test. Screen printing does not supply sufficient print paste (containing embossing agent) to the nylon carpet pile to provide a completely uniform coating of the nylon fibers. Furthermore, the depth of penetration into the carpet pile is often of the order of only about 50%. Also, during steaming, the concentration of the embossing agent may be reduced, and chemical which may be consumed is not replaced. However, in the beaker test, the nylon loop is surrounded constantly and uniformly by a surplus of hot chemical solution of practically the same concentration throughout the duration of the test thus allowing the chemical to function more effectively.

The following examples will further illustrate the embodiment of this invention. In these examples, all parts given are by weight unless otherwise noted.

EXAMPLE I

The shrinkage and weight loss experienced by a test loop of DuPont type 846 bulk continuous filament nylon 6/6 (1,300 denier, 68 filaments, o twist, semi-dull, regular acid dyeable) was determined by means of the beaker test procedure described in Table I using benzotriazole in conjunction with glacial acetic acid in water. Test results in Table II show that, for example, an embossing system comprising benzotriazole 20% and acetic acid 15% and water 65% causes the nylon loop to shrink 52% accompanied by a weight loss of 2.3% in the shrunk fibers without deterioration of the fiber properties in 15 minutes at 215.degree.F (Run No. 676). However, the concentration of embossing agent which produces this degree of nylon shrinkage in the beaker test generally produces little or no shrinkage when screen printed on nylon carpet face pile. Therefore, the beaker test procedure was further utilized to determine the concentrations and proportions of benzotriazole and acetic acid that would cause the nylon test loop to disintegrate within 60 seconds. As indicated previously, this degree of attack of the nylon filament in the beaker test is indicative of the substantial embossment that can be expected to develop when nylon carpet is treated with the embossing agent using a screen printing technique. The test temperature was 215.degree.F.

Test results are shown on Table 11 for various benzotriazole/acetic acid systems as well as for those combinations having small portions of acetic acid replaced by other acids such as sulfuric acid, formic acid, phosphoric acid, and toluenesulfuric acid. It is understood that percentages shown represent the percent contained in an aqueous solution. Also shown are shrinkage and weight loss values for individual components at intermediate and maximum concentrations used. A variety of concentrations and porportions of benzotriazole and acetic acid were found to disintegrate the nylon test loop fibers within less than 60 seconds, e.g., 35/25, 35/20, 30/25, 25/30, 27.3/27.3, 15/45, 15/47.3, 10/50, 12.5/47.5, as well as benzotriazole 15%/acetic acid 45%/85% phosphoric acid 2.7%.

Thus, these data show that the combination of benzotriazole and acetic acid has the capability to cause nylon fibers to shrink strongly and therefore is a potentially good embossing agent for nylon carpet. The replacement of small portions of acetic acid by other acids offered no particular advantage.

TABLE II __________________________________________________________________________ Nylon Filament Weight Run Shrinkage Loss Loop No. Chemicals* (%) (%) Character __________________________________________________________________________ ** Water 10.5 1.27 Good 673 Benzotriazole (BTA)***, 10% 43.0 +6.83 Good 672 Benzotriazole***, 20% Gummy mass 3 minutes 671 Benzotriazole***, 30% Gummy mass 20 seconds 681 Benzotriazole***, 35% **** Disintegrate 12 seconds 682 Benzotriazole***, 40% **** Disintegrate 10 seconds 680 Benzotriazole***, 50% **** Disintegrate 10 seconds 357 Acetic Acid, 30% 13.5 1.06 Good 659 Acetic Acid, 45% 27.0 3.92 Good 668 Acetic Acid, 50% 35.5 6.73 Good 669 Acetic Acid, 55% Broken loop 15 minutes 670 Acetic Acid, 60% Fragmented 15 minutes 337 Acetic Acid, 45%/85% Phosphoric Acid, 2.7% 29.7 3.89 Good 342 Acetic Acid, 59.3%/85% Phosphoric Acid, 3.7% Start disintegrate 10 minutes 258 BTA, 35%/Cellosolve Solvent, 25% 38.2 4.45 Good 405 BTA, 20%/Isopropyl Alcohol, 40% 18.2 0.19 Good 676 BTA, 20%/Acetic Acid, 15% 52.2 2.32 Good 675 BTA, 25%/Acetic Acid, 15% Broken loop 15 minutes 679 BTA, 40%/Acetic Acid, 15% **** Disintegrated 12 seconds 674 BTA, 50%/Acetic Acid, 15% **** Disintegrated 8 seconds 254 BTA, 35%/Acetic Acid, 25% **** Disintegrated 10 seconds 265 BTA, 35%/Acetic Acid, 20% **** Disintegrated 10 seconds 267 BTA, 35%/Acetic Acid, 15% Fragmented 15 minutes 264 BTA, 30%/Acetic Acid, 25% Disintegrated 15 seconds 257 BTA, 30%/Acetic Acid, 20% Fragmented 15 minutes 266 BTA, 25%/Acetic Acid, 25% Fragmented 15 minutes 274 BTA, 25%/Acetic Acid, 30% **** Disintegrated 30 seconds 318 BTA, 27.3%/Acetic Acid, 27.3% **** Disintegrated 30 seconds 324 BTA, 20%/Acetic Acid, 35% Mostly disintegrated 15 minutes 338 BTA, 15%/Acetic Acid, 47.3% **** Disintegrated 10 seconds 391 BTA, 15%/Acetic Acid, 45% **** Disintegrated 25 seconds 392 BTA, 10%/Acetic Acid, 50% **** Disintegrated 25 seconds 393 BTA, 10%/Acetic Acid, 45% Fragmented 15 minutes 394 BTA, 5%/Acetic Acid, 55% Fragmented 15 minutes 398 BTA, 25%/Acetic Acid 27.5% Fragmented 6 minutes 402 BTA, 12.5%/Acetic Acid, 47.5% **** Disintegrated 60 seconds 263 BTA, 35%/Acetic Acid 12.5%/ Cellosolve Sol. 12.5% Fragmented 15 minutes 292 BTA, 25%/Acetic Acid 22.5%/ Sulfuric Acid, 2.5% Friable 15 minutes 293 BTA, 25%/Acetic Acid 22.5%/90% Formic Acid 2.8% 72.4 21.6 Friable 295 BTA, 25%/Acetic Acid 22.5%/85% Phosphoric Acid 3.3% Fragmented 15 minutes 327 BTA, 25% Acetic Acid 20%/85% Phosphoric Acid 6% 79.7 25.0 Friable 335 BTA, 15%/Acetic Acid 45%/85% Phosphoric Acid 2.7% **** Disintegrated 20 seconds 300 BTA, 25%/Acetic Acid 22.5%/95% Toluenesulfonic Acid 2.6% Fragmented 15 minutes __________________________________________________________________________ *BTA = Benzotriazole. The benzotriazole is added to the acid solution to facilitate room temperature solubility. **Avg. of 13 runs water alone at 212.degree.F. ***Approx. 200.degree.F required to solubilize BTA in water. ****Deeply embossed carpet can be anticipated in those instances where th beaker test shows the test loop disintegrating within about 60 seconds. However, it may occur that such beaker disintegrating times are too destructive for carpet embossment. Then, the chemical concentration must be regulated to produce a longer time to test loop disintegration.

EXAMPLE II

The shrinkage and weight loss experienced by a test loop of DuPont type 846 bulk continuous filament nylon 6/6 (1,300) denier, 68 filament, O-twist, semi-dull, regular acid dyeable) was determined by means of the beaker test procedure described in Table I using the following aqueous recipes shown in Table III containing a combination of benzotriazole and an acid other than acetic acid. The test temperature and maximum duration of test was 215.degree.F and 15 minutes respectively.

While the preferred acid is acetic acid as described in Example 1, other acids such as formic, phosphoric, citric, hydroxyacetic, oxalic, propionic, maleic, acrylic, hydrochloric, monochloroacetic and sulfuric will also function in combination with benzotriazole to produce shrinkage of nylon fibers. Test results are recorded in Table III. It is understood that the percentages of components shown represent the percent of each contained in an aqueous solution. These data shown that by properly selecting the concentrations and proportions of benzotriazole and any one or more of these acids, the resulting chemical system can be expected to emboss nylon carpet via shrinkage of the fibers. As indicated, previously, it is generally necessary to obtain nylon fiber disintegration within 60 seconds in the beaker test in order to provide a benzotriazole/acid combination that will substantially emboss nylon carpet. Usually, little or no carpet embossment can be expected until beaker test shrinkage values exceed 50%. Whenever beaker test results show a disintegration time of more than 60 seconds, the concentration of one or both components of the benzotriazole/acid embossing system should be increased in order to realize a system that will deeply emboss nylon carpet. Lesser depths of embossment can be obtained, of course, by employing benzotriazole/acid combinations which increase disintegration times.

TABLE III __________________________________________________________________________ Nylon Filament Shrink- Weight Run age Loss Loop No. Chemicals* (%) (%) Character __________________________________________________________________________ ** Water 10.5 1.27 Good 672 Benzotriazole, 20%*** Gummy mass 3 minutes 681 Benzotriazole, 35%*** Disintegrated 12 seconds 150 90% Formic Acid, 33.3% 16.6 0.67 Good 688 Maleic Acid, 25% 13.8 0.71 Good 687 Propionic Acid, 25% 19.2 2.28 Good 348 Acrylic Acid, 25% 16.0 1.05 Good 686 Sulfuric Acid, 10% 8.2 0.19 Good 92 Citric Acid, 50% 23.8 +4.03 Good 685 37% Hydrochloric Acid, 26.7% 43.5 16.3 V. Weak 684 70% Hydroxyacetic Acid 35.7% 8.43 0.58 Good 683**** Oxalic acid 2H.sub.2 O, 35% 19.6 1.80 Good 70 Monochloroacetic Acid, 25% 29.3 2.71 Good 151 85% Phosphoric Acid, 29.3% 16.5 +2.36 Good 283 BTA, 35%/Monochloracetic Acid, 25% Disintegrated 10 seconds 296 BTA, 25%/Monochloroacetic Acid, 25% Disintegrated 20 seconds 286 BTA, 25%/Monochloroacetic Acid, 20% Mostly disintegrated 15 minutes 316 BTA, 25%/Acetic Acid, 13%/Mono- chloroacetic Acid, 12% Partial disintegrated 7 minutes 284 BTA, 35%/Propionic Acid, 25% Disintegrated 10 seconds 303 BTA, 25%/Maleic Acid, 25% Fragmented 15 minutes 304**** BTA, 25%/85% Phosphoric Acid, 25% 61.8 1.80 Friable 315**** BTA, 25%/85% Phosphoric Acid, 29.3% 62.0 3.16 Friable 317 BTA, 25%/Oxalic Acid-2H.sub.2 O, 35% Friable 15 minutes 325 BTA, 25%/70% Hydroxyacetic Acid, 35.7% 57.1 2.10 Good 326 BTA, 25%/37% Hydrochloric Acid, 13.3% 38.6 1.17 Good 328 BTA, 25%/Citric Acid.H.sub.2 O, 25% 65.6 +2.1 Brittle 329 BTA, 25%/37% Hydrochloric Acid, 26.7 55.8 16.4 Fragile 330 BTA, 25%/Sulfuric Acid, 10% 36.3 0.35 Good 349 BTA, 25%/Acrylic Acid, 25% Fragmented 15 minutes 678 BTA, 15%/88% Formic Acid, 17% 49.3 0.97 Good 677 BTA, 20%/88% Formic Acid, 17% Broken loop 15 minutes __________________________________________________________________________ ** Avg. 13 runs water alone at 212.degree.F. * BTA = Benzotriazole. The BTA is added to the acid solution to facilitat room temperature solubility. *** Soluble about 200.degree.F. **** Soluble above 170.degree.F.

EXAMPLE III

The shrinkage and weight loss experienced by a test loop of DuPont type 846 bulk continuous filament nylon 6/6 (1,300 denier, 68 filaments, O-twist, semi-dull, regular acid dyeable) was determined by means of the beaker test procedure described in Table I using the aqueous recipes shown in Table IV containing azoles other than benzotriazole and glacial acetic acid. The test temperature and maximum duration of testing was 215.degree.F and 15 minutes respectively. Test results are recorded in Table IV.

These data show that there are a number of substituted products and analogues of benzotriazole, representative of the mono, di, tri, and tetra azoles, which can function as shrinking agents for nylon fibers. Depending upon the azole employed and the ratio and concentrations of acid and azole used, the extent of shrinkage can range from very weak after 15 minutes at 215.degree.F to total disintegration of the nylon filament within 60 seconds. Combinations which produce this latter effect can be anticipated to produce strong carpet embossment.

While the preferred acid is acetic acid, other acids should be just as effective with other azoles as with benzotriazole (See Example II).

TABLE IV __________________________________________________________________________ Nylon Filament ** Acetic Sol.* Shrink- Wt. Run Azole Acid at age Loss Loop No. Type (%) (%) RT. (%) (%) Char. __________________________________________________________________________ 788) 778) Tap Water 0 0 -- 7.03 0.68 Good 804) 357 Acetic Acid 0 30 Y 13.5 1.06 Good 659 Acetic Acid 0 45 Y 27.0 3.92 Good AZOLE __________________________________________________________________________ 826 Pyrrole 25 30 Y Disintegrate 5 secs. 856 Pyrrole 20 25 Y 80.2 15.6 Friable 850 Pyrrole 15 45 Y Disintegrate 8 secs. 846 Pyrrole 35 -- N Disintegrate 3 secs. 827 Indole 25 30 N Disintegrate 5 secs. 829 2-Methylindole 25 30 N Disintegrate 10 secs. 828 N-Methylpyrrole 25 30 N 32.5 2.22 Good DIAZOLE __________________________________________________________________________ 822 Pyrazole 25 30 Y 44.5 11.4 Good 847 Pyrazole 35 0 130 27.1 3.9 Good 815 3,5-Dimethylpyrazole 25 30 Y 24.2 4.1 Good 813 5-Aminoindazole 25 30 Y 19.0 0.5 Maroon 814 5-Chloroindazole 25 30 210 Disintegrate 45 secs. 851 5-Chloroindazole 15 45 170 Disintegrate 10 secs. 276 Imidazole 25 30 Y 9.5 0.6 Good 207 Imidazole 50 0 Y 27.3 7.2 Good 275 Benzimidazole 25 30 Y 18.6 +0.6 Good 812 1-Methylimidazole 25 30 Y 8.1 0.6 Good TRIAZOLE __________________________________________________________________________ 735 Benzotriazole 25 30 Y Disintegrate 35 secs. 857 Benzotriazole 20 25 Y 61.3 8.1 Good 391 Benzotriazole 15 45 Y Disintegrate 25 secs. 681 Benzotriazole 35 0 200 Disintegrate 12 secs. 825 1-Methylbenzotriazole .H2O 25 30 Y 32.9 6.1 Good 741 1-Hydroxybenzotriazole 25 30 180 65.7 7.8 Fragile 746 5-Chlorobenzotriazole 25 30 190 Disintegrate 40 secs. 832 1-Hydroxybenzotriazole .H2O 28.3 30 180 Fragmented 15 mins. 737 1,2,4 - Triazole 25 30 Y 20.5 2.9 Good 738 3-Amino-1,2,4-Triazole 25 30 150 13.0 1.5 Good 830 Urazole 25 30 215 20.9 1.7 Good TETRAZOLE __________________________________________________________________________ 820 5-Aminotetrazole.H2O 25 30 200 33.2 4.9 Good 831 5-Aminotetrazole.H2O 30.5 30 200 40.1 7.0 Good 852 5-Aminotetrazole.H2O 15 45 190 62.8 28.8 Fragile 849 5-Aminotetrazole.H2O 35 0 215 7.8 +0.3 Good 883 1,5-Pentamethylenet- etrazole 25 30 Y 22.5 4.67 Good OXAZOLE __________________________________________________________________________ 821 2-Methylbenzoxazole 25 30 Y 41.3 2.7 Brown ISOOXAZOLE __________________________________________________________________________ 809 5-Methylisoxazole 25 30 Y 30.8 6.7 Good 808 3,5-Dimethylisoxazole 25 30 Y 26.2 5.9 Good THIAZOLE __________________________________________________________________________ 833 Benzothiazole 25 30 N Fragmented 15 mins. 853 Benzothiazole 15 45 Y 82.3 36.7 Fragile 818 Aminothiazole 25 30 Y 13.8 0.7 Brown 823 2-Amino-6-Methoxy- benzothiazole 25 30 Y 24.6 +0.5 Good 816 2-Methylbenzothiazole 25 30 N 34.8 +19.2 Wk. spot 844 2-Chlorobenzothiazole 25 30 N 26.0 +3.1 Good OXADIAZOLE __________________________________________________________________________ 855 3,4 Dimethylfurazan 25 30 Y 34.4 7.7 Good THIADIAZOLE __________________________________________________________________________ 825 2,1,3-Benzothiaziazole 25 30 N 23.0 2.3 Good __________________________________________________________________________ * RT = room temperature. Y=Yes N=insoluble or immicible even at 215.degree.F. Other figures indicate temperature .degree.F at which solubility occurs. ** 15 minutes at 215.degree.F unless otherwise indicated.

EXAMPLE IV

This example illustrates the preparation of an embossed pile fabric typical of the products of this invention.

A 4 inch by 7 1/2 inch rectangular area of nylon carpet was treated by means of a screen printing technique with a dye print paste containing 27.5% benzotriazole and 25% glacial acetic acid by weight as the embossing agent.

Carpet construction was as follows:

Type --100% nylon 6/6, spun yarn, non heat set

Face Weight -- 28 oz./yd. sq. (950 grams/sq. meter)

Machine Gauge -- 5/32 inch (3.96 millimeters)

Machine Stitch Rate --9.6 stitches/inch (3.8 stitches/centimeter)

Pile Height -- 17/32 inch, (1.35 centimeters) singles

The dye print paste was formulated as follows:

SAMPLE NO. 278SP Material * Grams ______________________________________ 1. Water 24.2 2. Cibaphasol AS 0.5 3. Antifoam 73 0.8 4. Kelzan (1%) (0.2% Dowicide A) 22.0 5. Acetic Acid, Glacial 25.0 6. Benzotriazole 27.5 7. Dye 0.1 ______________________________________ *2 = Sulfuric acid ester, Levelling and pentrating agent 3 = Alcohol ether, antifoaming agent 4 = Xanthan gum thickner plus preservative in water to provide a Brookfield viscosity of 760 cps. at 78.degree.F (No. 3 Spindle, 21/2 rpm.

There was no evidence of embossing while the nylon carpet was held at room temperature for several minutes. Upon subjecting the carpet to steaming for 15 minutes at about 218.degree.F, significant embossing due to fiber shrinkage was observed. Thereafter, the embossed carpet was throughly rinsed with water and dried. The rinsing removed residual chemicals. The embossed nylon pile was rubbed briskly.

The resulting carpet exhibited excellent embossing with a 44% reduction in pile height in the treated area in perfect register with the printed rectangle. Despite this degree of shrinkage, the nylon tufts retained their individuality and, while increasing in firmness remained acceptably soft. There was no evidence of deterioration of fiber physical properties.

EXAMPLE V

The nylon carpet construction cited in Example IV was again treated by means of a screen printing technique. However, in this case the concentration and proportion of benzotriazole and acetic acid were changed substantially so that the dye print paste contained 15% benzotriazole and 45% glacial acetic acid by weight as the embossing agent.

The dye print paste used was as follows:

SAMPLE NO. 411SP Material * Grams ______________________________________ 1. Water 17.2 2. Cibaphasol AS 1.0 3. Antifoam 73 0.8 4. Polygum 260 (5%) 21.0 5. Acetic Acid, Glacial 45.0 6. Benzotriazole 15.0 7. Dye 0.05 ______________________________________ *4 -- Locust bean gum thickener providing a Brookfield viscosity of 1,200 cps. at 78.degree.F (No. 3 spindle, 21/2 rpm)

Once again there was little evidence of embossing while the nylon carpet was held at room temperature. Upon subjecting the carpet to steaming at about 215.degree.F for a period of 15 minutes, significant embossing due to shrinkage of the nylon carpet pile was noted. Thereafter, the embossed carpet was rinsed and dried. The embossed nylon pile was rubbed briskly.

The resulting carpet exhibited an area with a 41% reduction in pile height in register with the printed area. The shrunk tufts were well defined, strong and while somewhat firmer, were acceptable soft.

While it is obvious that a number of concentrations and proportions of benzotriazole and acetic acid serve very effectively as embossing agents for nylon carpet (see Example VI, Table V), generally that combination of benzotriazole and acid will be selected so as to provide the desired embossment most economically. Thus, since benzotriazole is by far the more expensive component, the most economical combination will comprise a low concentration of benzotriazole and a high concentration of acetic acid such as shown by the subject example.

EXAMPLE VI

Additional embossed nylon carpets were prepared by means of the embossing procedure described in Example IV, hereinabove, utilizing various concentrations and proportions of benzotriazole and acetic acid contained in the dye print paste as shown in Table IV. Corresponding depths of embossment and embossed pile character are indicated in Table V.

TABLE V __________________________________________________________________________ Carpet Embossment Sample BTA/Acetic Acid* Paste** Depth No. (% in Paste) Visc. (cps.) (%) Pile Character __________________________________________________________________________ 262SP 35/25 360 53 Hard, Harsh 271SP 25/25 480 31 Soft, Good 279SP 30/25 760 50 V. Firm, Harsh 299SP 35/20 720 50 V. Firm, Harsh 301SP 28/25 520 44 Firm, Good 320SP 25/30 960 41 Firm, Good 328SP 27.3/27.3 760 44 Firm, Good 371SP 25/30 1160 47 Firm, Good 372SP 15/45 1480 47 Firm, Good 392SP 10/50 1320 35 Soft, Good 399SP 3/60 1200 35 Soft, Good 418SP 15/45 1000 41 Firm, Good __________________________________________________________________________ * BTA = Benzotriazole ** Brookfield 78.degree.F, No. 3 spindle, 21/2 rpm. Xanthan gum thickener all samples.

In recapitulation, it is to be understood that the process of embossed carpet involves manipulation corresponding to that of printing a pattern on the carpet. Where mere embossment is sought the printed composition is colorless. Where the design combines color with the embossment a dye paste is the vehicle generally, whether the operation be a mere embossment or an embossment combined with dyeing. It is preferred that there be no shrinkage of the nylon fibers at ambient temperatures, even up to 50.degree.C. In plant operations the delay from printing to steaming may be as such as 8-10 minutes. Hence, if there is no significant effect on the material at temperatures below 50.degree. C for 15-20 minutes there is ample time for operations. That is, activation of the shrinkage is reserved for the stage where the printed material enters the steaming operation. In standard carpet handling the steaming is a 10-20 minute operation to fix the dye and in this stage the embossing is completed in the first few minutes.

For effective embossment there should be at least perceptible shrinkage in the tufts. Generally penetration of the embossing print paste will be of the order of 50%. Where it is desired to have full depth coloration of the printed area uniformly to the back of the fabric, this can be accomplished by predying the carpet completely to the back by means of an operation such as pad dyeing. Where it is desired to have full coloration of the area uniformly to the back of the fabric it is desirable to predye the carpet completely to the back by means of an operation such as pad dyeing. It should be apparent that in operations where mere embossment is sought there is no significant problem in the placement of the design on the fabric. Where embossment is combined with a multi-colored print there is the register problem and the color area will be in perfect register with the embossed design when the shrinking agent is combined with the color paste as set forth in detail in the examples.

It is thus seen from this data, that a variety of concentrations and proportions of benzotriazole and acetic acid are readily applicable to the novel process of this invention.

In the production of the pile fabrics of this invention, the pile yarn employed is prepared from fiber-forming synthetic linear polyamides. Examples of these fiber-forming synthetic linear polyamides are those obtainable from polymerizable monoaminomonocarboxylic acids and their amide-forming derivatives including caprolactam and those obtainable from the reaction of suitable diamines with suitable dibasic carboxylic acids or their amide-forming derivatives. Such synthetic linear polyamides are referred to as nylon.

Nylon or polyamide polymers, filaments and fibers are well known to those skilled in the art and extensive discussion is, therefore, unnecessary. Thus the term "polyamide" or "nylon" is known to include any long chain synthetic polymeric amide which has recurring amide groups as an integral part of the main polymer chain and which is capable of being formed into a filament in which the structural elements are oriented in the direction of the axis of that chain.

Polyamide resins coming within this definition and contemplated in the practice of the present invention are formed generally by reaction of a diacarboxylic acid with a diamine or by a self-condensation of an aminocarboxylic acid. Illustrative of these polyamide resins are nylon -6,6, prepared by the condensation of hexamethylenediamine and adipic acid; nylon -6,10, prepared from hexamethylenediamine and sebacic acid, both of the foregoing having, as prepared, molecular weights exceeding 10,000: nylon-6 produced by thermal polymerization of epsilon-aminocaproic acid of caprolactam; nylon-11, the self-condensation products of 11-aminoundecanoic acid; as well as a variety of polymers prepared from polymerized, unsaturated fatty acids and polyamine compounds.

The practice of the present invention has, however, particular application to solid melt-extrudable and orientable fiber-forming polyamides and more particularly to fibers and filaments prepared therefrom which have a denier and tenacity appropriate, and well known to those skilled in the art, for use in carpet, rugs, tapestry and the like. Illustrative of these polyamides are those having a filament denier of 2-30 or higher or nylon yarns in the denier range of 15-15,000 or higher. The tenacities of nylon yarn for use herein are within the range of 3-10 grams per denier. The elongation of commercial fibers can range between 15 and 65%. The undrawn filament is capable of being stretched as much as 5 times. It is understood additionally that encompassed within the polyamides that can be employed in the practice of this invention are high molecular weight synthetic linear polyamides, in addition to those described hereinabove, that have been modified, for example, to enhance their usefulness for particular applications.

An extended discussion of polyamides of sufficiently high molecular weight to be capable of being melt spun into filaments and coming within the contemplation of this invention appears in D. E. Floyd, Polyamide Resins, Reinhold Plastics Application Series, Reinhold Publishing Corporation, New York, N.Y. (2d printing, 1961), and H. R. Mauersberger, Matthews' Textile Chemical Properties, John Wiley and Sons, Inc., New York, N.Y., pp. 933-971, 1034., (6th ed. 1954), Mary E. Carter, Essential Fiber Chemistry, Marcel Dekker, Inc., New York, N.Y. 1971 pp. 91-109, H. F. Mark, S. M. Atlas, E. Cernis (Edited by), Man-Made Fibers, Science and Technology, Volume 2, Interscience Publishers 1968, pp. 181-295, Tech.-Talk from Monsanto Textiles Division Bulletin TT-35 August 1969.

Summarizing, it is thus seen that this invention provides a novel and effective method for embossing nylon pile fabrics.

Variations may be made in procedures, proportions, and materials without departing from the scope of the invention as defined in the following claims.

Claims

What is claimed is:

1. A process for producing an embossed effect on nylon pile fabric having a surface of nylon fibers which comprises,

applying to defined areas of the pile surface of said fabric a chemical embossing agent for said fibers,

said agent being an azole having a five membered heterocyclic aromatic ring or fused aromatic ring containing two or more heteroatoms, in the five membered ring, at least one of which is always nitrogen, blended into a liquid base vehicle, said liquid base vehicle also including an acid,

allowing said embossing agent in its vehicle to remain in contact with said fibers for a period of time and at a temperature sufficient to reduce the height of said pile, without deterioration of said fibers,

and, thereafter, effectively removing the embossing agent from the fabric,

said reduction in height of the fibers being in the area contacted by said embossing agent only and being a reduction sufficient to display a significant embossed effect in the overall fabric.

2. A process of claim 1 wherein said embossing agent is benzotriazole with acetic acid in concentrations of 5% to 50% benzotriazole and 15% to 60% glacial acetic acid by weight, of total embossing composition.

3. A process of claim 2 wherein said embossing agent is incorporated in a transparent vehicle therefor.

4. A process of claim 2 wherein said embossed effect is made in register with a printed color design on said fabric and

said vehicle is a dye printing paste carrying said embossing agent.

5. The process of claim 2 wherein said embossing action occurs within approximately 15 minutes at a temperature above 50.degree.C.

6. A process in accordance with claim 5 wherein said embossing action occurs in a steam environment.

7. A process of claim 6 wherein said embossing composition is present in a concentration of about 45 to 65% in the vehicle therefor.

8. A process of claim 7 wherein said embossing agent is benzotriazole and hydroxyacetic acid.

9. A process of claim 7 wherein said embossing agent is benzotriazole and formic acid.

10. A process of claim 7 wherein said embossing agent is benzotriazole and phosphoric acid.

11. A process of claim 7 wherein said embossing agent is benzotriazole and oxalic acid.

12. A process of claim 7 wherein said embossing agent is benzotriazole and hydrochloric acid.

13. A process of claim 7 wherein said embossing agent is benzotriazole and propionic acid.

14. A process of claim 7 wherein said embossing agent is benzotriazole and citric acid.

15. A process of claim 7 wherein said embossing agent is benzotriazole and sulfuric acid.

16. A process of claim 7 wherein said embossing agent is benzotriazole and maleic acid.

17. A process of claim 7 wherein said embossing agent is benzotriazole and monochloroacetic acid.

18. A process of claim 7 wherein said embossing agent is benzotriazole and acrylic acid.

19. A process of claim 7 wherein said embossing agent is pyrrole and acetic acid.

20. A process of claim 7 wherein said embossing agent is indole and acetic acid.

21. A process of claim 7 wherein said embossing agent is 2-methylindole and acetic acid.

22. A process of claim 7 wherein said embossing agent is pyrazole and acetic acid.

23. A process of claim 7 wherein said embossing agent is 5-chloroindazole and acetic acid.

24. A process of claim 7 wherein said embossing agent is 5-chlorobenzotriazole and acetic acid.

25. A process of claim 7 wherein said embossing agent is 1-hydroxylbenzotriazole monohydrate and acetic acid.

26. A process of claim 7 wherein said embossing agent is 5-aminotetrazole monohydrate, and acetic acid.

27. A process of claim 7 wherein said embossing agent is benzothiazole and acetic acid.