|Publication number||US3632296 A|
|Publication date||Jan 4, 1972|
|Filing date||Apr 12, 1968|
|Priority date||Apr 12, 1968|
|Publication number||US 3632296 A, US 3632296A, US-A-3632296, US3632296 A, US3632296A|
|Inventors||Pandell Nestor W, Temin Samuel C|
|Original Assignee||Cluett Peabody & Co Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (1), Referenced by (9), Classifications (28)|
|External Links: USPTO, USPTO Assignment, Espacenet|
6 United States atent Inventors Nestor W. Pandell Waocabuc, N.Y.;
Samuel C. Temin, Needham, Mass. Appl. No. 721,102 Filed Apr. 12, 1968 Patented Jan. 4, 1972 Assignee Cluett, Peabody & Co., Inc.
New York, N.Y.
APPLICATION OF REACTANTS AND/OR CATALYSTS T0 TEXTILE FABRICS IN MICROENCAPSULATED FORM 22 Claims, No Drawlngs Int. Cl D06m13/l4, D06m 13/20, D06m 13/38 Field oISearch 8/116.3,
116.4, 1 15.5, 120, 128;252/l82, 316; 38/144; 117/1388 N, 138.8 PV, 138.8 F, 138.8 8,138.8 R,139.4, 141
 References Cited UNITED STATES PATENTS Assistant Examiner-.1. Cannon Attorneys-Leo Fomero and Robert .1. Dockery ABSTRACT: Process for imparting improved wrinklerecovery and crease-retention characteristics, frequently referred to as durable press or wash-and-wear characteristics, to textile fabrics containing at least some reactive fibers usually natural fibers such as cellulosic or regenerated cellulose fibers, by cross-linking such fibers in delayed-cure or conventional procedures. Either the resin or other cross-linking material or materials or the catalyst, when a catalyst is used, may be encapsulated in microcapsules. Alternatively, both the cross-linking material or materials and the catalyst are thus encapsulated. The capsules are applied to the fabric, before or after or simultaneously with the application of such unencapsulated materials as may be used, to sensitize the fabric for subsequent cross-linking operation. Cross-linking is effecting when desired usually by application of heat and/or pressure to the sensitized fabric, to release the encapsulated materials and to complete the reaction.
APPLICATION OF REACTANTS AND/OR CATALYSTS TO TEXTILE FABRICS IN MICROENCAPSULATED FORM BACKGROUND OF THE INVENTION 5 Durable-press fabrics and methods for imparting durable press characteristics to fibers, yarns or fabrics, incorporating at least some natural or otherwise reactive fibers, such as cotton, linen andlor regenerated cellulose, are known in many forms. In a general sense, with respect to fabrics incorporating such fibers, resins or other crosslinking agents are applied to the fabric and in the presence of a catalyst the fabric is heated to a temperature at which cross-linking of the reactive fibers (broadly referred to as curing" of the fabric) will occur at the desired rate. According to the conventional procedure the curing is performed by the fabric manufacturer. According to the delayedcure procedure the fabric is sensitized by the fabric manufacturer and the sensitized fabric (that is, one with the crosslinking agent and catalyst applied but not cured) is delivered to a manufacturer who makes it into a product such as a garment, bedsheet or the like which is fashioned into a geometric configuration which it is desired that the final finished product retain during use. The sensitized, shaped fabric is then subjected to heat so that the crosslinking operation is performed or completed with the product in the desired configuration. Thus in the case of a bedsheet the crosslinking is performed while the product is held in smooth flat condition and in the case of a garment it is smoothed and sometimes creased or pleated before final crosslinking is perfonned.
For use in delayedcure procedures the fabric usually is sensitized with a resin-catalyst system. Therefore it is essential that the resincatalyst system be sufficiently stable that advancement of the cure or deterioration of resin or of catalyst will not occur or at least will not proceed at an appreciable rate during the time that the fabric is being shipped to the garment manufacture, stored and is being made into a gannent. If the rate of curing reaction under storage conditions, for example, is appreciable the fabric will be at least partially cured in the geometric form in which it was stored and thus will not be entirely suitable for delayedcure after product manufacture is complete. If either or both the resin and catalyst deteriorate the final cure will be adversely afiected. Also, some resins have components that will volatilize at room or storage temperatures not only causing deterioration" of the resin but also giving of? objectionable odors. These requirements have lead to the development of various resin-catalyst systems which are sufficiently stable for manufacture of the product to be finished and appreciable storage to occur before a substantial amount of crosslinking has occurred and with the resin and catalyst in active available condition. These relatively stable resincatalyst systems, however, require delayedcuring operations which include exposure of the finished garment to quite high temperatures for substantial periods of time. Thus the garment manufacturer who manufactures the garment must have available to him expensive curing equipment in which the garments may be maintained at the requisite temperature for the requisite time.
BRIEF DESCRIPTION OF THE INVENTION The present invention provides a process whereby a wide range of crosslinking materials may be employed in the delayedcure systems. Instead of being limited to the use of carefully selected combinations of stable resins and stable or slowly acting catalysts, the present invention makes it possible to use many resins as well as other crosslinking agents which are unstable, volatile or unacceptably odorous themselves or are unstable in the presence of a catalyst. Also it makes it possible to use more active or volatile catalysts.
To accomplish the purposes of the present invention either the resin or other crosslinking agent or the catalyst is encapsulated in accordance with the wellknown technique of microencapsulating whereby the resin and catalyst can be maintained separated until it is desired that they react. For ex- 75 ample when resins are used the resin may be padded, in the form of an aqueous or other suitable solution or suspension onto the fabric and the catalyst, encapsulated in suitable capsulating material, may be applied to the fabric simultaneously with or before or after the application of the resin. The fabric thereafter may be shipped, stored and subjected to conversion operations, after which the finished fabric product is subjected to conditions which release the catalyst from the capsules. The catalyst is thus made available for the delayed curing operation which can be carried out at any temperature and/or mechanical pressure appropriate for releasing the encapsulated catalyst and for causing desired crosslinking. In some cases the catalyst may be an active one and the releasing of the catalyst may be effected so easily that the resin can be cured very rapidly at moderate temperature and pressure thus obviating the need for expensive curing equipment.
Similarly the purposes of the present invention may be achieved by encapsulating the resin or other cross-linking agent. The encapsulated material then could withstand storage conditions which would cause deterioration of the material if it were not encapsulated. Also resins or other crosslinking materials may be used which will react rapidly at moderately elevated temperatures in the presence of a catalyst of appropriate activity. Such resins or other materials may be quite unstable or may include volatile or strongly odorous components. In this case the catalyst may be padded onto the fabric in a suitable vehicle or solvent and the encapsulated resin or other agent may be applied simultaneously with or before or after the application of the catalyst. Thus, it is possible to effect release of the resin or crosslinking agent from the capsules when desired either for conventional or for delayedcure durable press procedures. By the selection of resins or other agents and catalysts of suitable activity it is possible to effect a final cure at such elevated temperature and/or pressure as may be desired including those ordinarily available in steampressing or domestic ironing procedures.
Also within the scope of the present invention both the crosslinking resin or other material and the catalyst or any two or more potentially reactive components, may be encapsulated and applied to the fabric simultaneously or sequentially in suitable manner. The encapsulated materials will remain out of contact with one another and will be individually sealed against deterioration until such time as rupture of the capsules is caused. By proper selection of resin or other agents, catalysts and encapsulating materials the final cure may be brought about under suitable temperature and/or pressure conditions, including, if so desired, the moderately elevated temperatures and pressures available with commercial or domestic steampressing or ironing equipment.
DESCRIPTION OF PREFERRED EMBODIMENTS First illustrative embodiments of the present invention were made by encapsulating aqueous solutions of zinc chloride, in concentrations of 20 percent and 50 percent, in ethyl cellulose. The capsules ranged in size from about to about 175 microns with the possibility that such units were composed of many smaller particles. The zinc chloride solutions comprised about 72 percent of the total weight of such capsules. A cotton broadcloth fabric which previously had been padded with a resin, dimethylol cyclic ethylene urea (DMEU), and dried, was further treated by applying the capsules containing the zinc chloride solutions onto the fabric. The treated fabric was thereafter pressed between heated platens and its creaserecovery characteristics were evaluated. Further details and results will be given below.
Second illustrative embodiments of the present invention were made by encapsulating the DMEU resin described above, in ethyl cellulose. The capsules were screened and those passing through a NBS No. sieve (below 178 microns in diameter) were selected for use. A cotton broadcloth fabric which previously had been padded with an aqueous zinc chloride solution, and dried, was further treated by applying the encapsulated resin to the fabric. The treated fabric was thereafter pressed between heated platens and its creaserecovery characteristics were evaluated. Details and results will be given below.
In the embodiments described above the quantities of resin and catalyst were selected on the basis of commercial experience with these same materials without encapsulation. Thus, in one typical test of the first embodiment the padding of the DMEU resin onto the fabric (cotton broadcloth) was so conducted that the fabric picked up an amount of resin representing about 8 percent of the weight of the untreated fabric. The quantity of encapsulated catalyst (72 percent by weight zinc chloride solution, 28 percent ethyl cellulose) applied was so calculated as to supply zinc chloride representing about 1 percent of the weight of the untreated fabric. Thus, as will be evident, a larger quantity of encapsulated zinc chloride solution was applied when in the form of a 20 percent aqueous solution than when in the form of a 50 percent aqueous solution. In a typical test of the second embodiments, wherein the resin was encapsulated, the same relative quantities of resin and catalyst were applied to an identical fabric. As a control for these typical tests an identical fabric was padded with the same quantity of DMEU resin and was dried. Zinc chloride in the form of aqueous solutions identical with those encapsulated in the first embodiment was sprayed onto the resin-impregnated fabric and the fabric was immediately pressed between hot platens under the same temperatures and p'ressures as those used with the fabrics having encapsulated materials. The spraying of the catalyst solution was so conducted as to add the same amount of zinc chloride as was added to those fabrics in which one of the materials was encapsulated.
Samples of the three fabrics were then cured by pressing between steamheated platens at 300 F. for five minutes and were conditioned at 70 F., 65 percent RH. preparatory to creaserecovery angle evaluation in accordance with the well known Monsanto CRA test (ASTM Dl295- 6m").
As a further control the fabric which had been padded with catalyst only and which was identical with the fabrics to which encapsulated resin was added as disclosed above, was pressed between heated platens at 300F. for minutes, just as were the other samples. This cured fabric, devoid of resin, was conditioned and evaluated in the same manner as the other samples. The Monsanto CRA (warp only) found for this fabric was 104". In contrast with this, the fabrics cured with padded resin and encapsulated catalyst were found to have a CRAA of l27when 50 percent zinc chloride solution was used and a CRA of 129 when percent zinc chloride was used. The fabrics cured with padded catalyst and encapsulated resin were found to have a CRA of 125". The control fabrics cured with padded resin and sprayed catalyst were found to have a CRA of 134". Samples of the fabric with padded resin and encapsulated zinc chloride (50 percent aqueous solution) were cured solely by ironing with a domestic hand iron (no pressure except for weight of iron) at about 300F. for about 5 minutes and after conditioning, the ironed samples exhibited a CRA of 130! From these results it will be apparent that the extent of improvement in crease recovery behavior of the cured fabrics having resincatalyst systems in which one of the materials was encapsulated was comparable with the behavior of the fabrics in which the resincatalyst system was completed by spraying of the catalyst just prior to curing.
Ethyl cellulose was selected as an encapsulating material at least partly because of its contribution to the physical properties of the fabric. A certain amount of wall material must remain as residue after release of the core material during cure. The material chosen for the wall (nonreactive portion of the capsule) is preferably of a nature such that it can help to impart a desirable hand to the fabric, i.e., function as a softener. If such a wall material is used, then it is possible to eliminate the separate addition to the pad bath of a substance designed to improve hand and abrasion resistance of the fabric. Wall materials falling in this category include polyethylene, polyethylene copolymers, poly acrylates, silicones, nylons and polyurethanes as well as cellulosic esters. Thus, an additional advantage of the process of this invention is that the relative amount of capsule wall (of the proper nature) may be adjusted so as to leave as residue a desired quantity of softener and thereby eliminate partially or completely one ingredient of the pad bath.
The resincatalyst system used in the embodiments discussed above, that is, DMEU resin and zinc chloride is one that is used commercially in conventional" durable press methods, as distinguished from delayedcure" methods. The encapsulation, according to the present invention, of the zinc chloride or of the DMEU resin, or both, enables the fabric manufacturer to apply such resincatalyst system to the fabric without curing it. The DMEU resin has a formaldehyde odor and if this is objectionable it may be preferred to encapsulate this resin with or without encapsulation of the catalyst.
The encapsulated material may be applied to the fabric in accordance with this invention in such manner as is appropriate for the particular encapsulating material or techniques used, the storage and handling conditions to be encountered before curing and the presence of other materials such as wetting agents, hand builders, abrasion resistance builders and the like, which may be needed or desired for different fabrics and end uses. if the encapsulating technique produces ethyl cellulose capsule walls which are somewhat porous, which is often the case, and thus would permit leaching out of the encapsulated material in aqueous vehicles, the capsules may be applied dry to the fabric or may be applied as suspensions in nonaqueous vehicles so long as the porosity is not so extensive as to unduly limit storage conditions. Many padding baths are aqueous and would require nonporous capsules. Porous or watersoluble capsule walls may be made nonporous and waterinsoluble by coating them with wax, for example, as will be described in detail below. Also different encapsulating materials may be used. By the latter procedures padding baths may be formulated whereby the unencapsulated as well as the capsulated materials of the resincatalyst system may be padded onto the fabric simultaneously or separately in aqueous or nonaqueous baths as may be desired.
As will be apparent from the above discussion the selection of encapsulating material and/or technique may be based on the nature of the padding bath or other procedure used for applying the capsules. On the other hand the padding bath or other application technique may be selected on the basis of the capabilities or limitations of the particular encapsulating material employed since in some instances the material which is to be encapsulated may have characteristics which more or less dictate the type of encapsulating material that may be used.
The present invention offers the possibility of employing more active catalysts with resins of the type customarily used with zinc chloride as the catalyst in the durable press field. For example, with the DMEU resin described above zinc nitrate is much more active than zinc chloride. Thus, it has been observed that with cotton broadcloth padded with DMEU as described above but in which zinc nitrate is used as a catalyst, curing to relatively high CRA angles can be effected at lower temperatures than are customarily used. Thus when such a fabric was cured at 70 F. (as a control) a Monsanto CRA (warp only) was observed to be 81". However with five minutes curing at 250F. the CRA angle was 134 ,at 300 F. was and at 350 F. (frequently used in commercial delayed cure procedures) the CRA angle was 143". Thus the 250cure produced very useful improvement in CRA while the 300cure produced results which were not exceeded by curing at 350". However, when the fabrics to which both the DMEU and zinc nitrate had been added, without encapsulation of either material, were subjected to accelerated aging tests the cure advanced so rapidly as to indicate impractical limitations on the time and temperature conditions under which such a fabric could be stored for delayed curing procedures. For example, such fabrics, when stored at 140F.
and percent RH for only one day advanced from a CRA angle (warp only) of 80 to ll0and after two days had advanced to about 125 with little further advancement up to 8 days. From this it will be appreciated that there is substantial likelihood that any folds or creases which exist in the fabric under storage would have assumed undesirable permanence before the fabric is made into a garment. In accordance with the present invention encapsulation of the resin or of the catalyst in encapsulating material suitable for the particular material and for the particular padding or other application procedure will serve to keep the members of the resincatalyst system apart whereby to avoid premature curing. In connection with the results pointed out in this paragraph it should be mentioned that the premature advancement of cure has little effect on the numerical value of the CRA which may be achieved by final curing at 300 F. for 5 minutes between heated platens. All of the aged and unaged samples reached a CRA, (warp only) of about I40after curing. The harmful effect of premature curing is the setting of wrinkles or creases which are difficult or impossible to press out.
The present invention also makes it possible to use in the durablepress field resins of catalystactivated type which are much too unstable, in the presence of a catalyst, to be used in delayed cure procedures. For example, Aerotex Cream 450, a monomeric urea formaldehyde (UF) resin manufactured by American Cyanamid Company may be used with encapsulated zinc chloride as a catalyst. Fabrics padded with 8 percent by weight of such UF resin were aged, without catalyst, at 70 F., 65 percent RH. The CRA angle (warp only) observed for the unaged fabric was 81 and after storage, under the ageing conditions aforesaid, for eleven days the CRA had advanced only to 93. However, the same resincontaining fabric to which 1 percent by weight of zinc chloride had been added exhibited a CRA angle of 92 before any aging and after only 7 days of aging at the conditions aforesaid had advanced to a CRA of about 120". It will be apparent that encapsulation of the zinc chloride or the resin in an appropriate encapsulating material would make it possible to obtain good creaserecovery results at temperatures well below those commonly used for the more popular procedures.
Another resincatalyst system, somewhat more stable than the one just discussed but still too unstable for delayed curing use, is a MF resin, Aerotex UM, manufactured by American Cyanamid Company, which is essentially a trimethylolated melamine with no etherification, with zinc nitrate as a catalyst. By encapsulating the zinc nitrate or the resin the rapid advancement of cure observed in aging tests can be avoided. In such aging tests a fabric padded (8 percent by weight) with the MF resin, with no catalyst exhibited a CRA (warp only) of 90 before aging and a CRA of 92 after aging 4 days at 70F 65 percent RI-l. When encapsulated zinc nitrate, 1 percent by weight on fabric, was added to the resincontaining fabric it exhibited a CRA (warp only) of 90 before aging and an insignificant increase in CRA after similar aging.
As will be observed from the preceding discussion the UF and MF resins selected for the reported tests are quite stable in the absence of a catalyst in available form whereby encapsulation of the catalyst rather than the resin is suggested as a preferred procedure. Among other things, the amount of catalyst is less than the amount of resin and where the resin and catalyst are to be kept apart by encapsulation of one or the other, the matter of cost favors the encapsulation of the material which is needed in lesser quantity. Also, the encapsulating material may be undesirable or, even if desirable, may be present in too great a quantity in the finally cured product if a large quantity of encapsulated material is used. In that event postcuring washing or other extraction procedures would be required and would add to the cost of a final product. However, many lowcost resins or resinforming agents or other crosslinking agents of nonresin type which are capable of giving excellent creaserecovery characteristics to fabrics have not been utilized because of instability of the run resin or agent even in the absence of a catalyst. Such instability is often manifested by the giving off of disagreeable odors as well as by the loss of chemical. By encapsulating such resins or agents in accordance with the present invention it is possible to utilize such materials in a delayedcure procedure which are so low in initial cost as to outweigh the possible disadvantages of encapsulating the more abundant material.
In an embodiment of the nonresin crosslinking reactions which the present invention make possible in delayed cure procedures a 37 percent formaldehyde solution in water was encapsulated, by a microencapsulation technique similar to that used in the preceding embodiments, in ethyl cellulose and those capsules passing through an NBS No. screen (178 microns) were selected for use. The capsules were sufficiently porous to be impractical for use in an aqueous suspension. They also gave off a strong formaldehyde odor. Accordingly, some of these capsules were coated with paraffin wax by agitating the same in a warm heptane solution of wax under vacuum until the solvent was evaporated. The waxcoated capsules after washing with water, were nonporous, free of formaldehyde odor and were not soluble in water thus assuring stability under padding and storage conditions appropriate for use in delayed-cure procedures. It was determined that waxcoatings made up of as little as 5 percent of the weight of the capsules were entirely satisfactory.
Even though the very small quantity of wax on the coated capsules could not be expected to have any material effect on creaserecovery results the evaluation tests were made with uncoated capsules. Thus, uncoated capsules were applied to cotton broadcloth fabric samples which previously had been padded to contain 1 percent by weight of zinc chloride. Sufficient capsules were spread upon the fabric samples to constitute a loading of the fabric with about 10 percent by weight of formaldehyde. Other similar fabric samples were loaded with the capsules in an amount equivalent to about 5 percent formaldehyde on the weight of the fabric. As a control, similar fabric samples were sprayed with a 37 percent formaldehyde solution in a quantity to give a formaldehydeloading equivalent to about 8 percent on the weight of the fabric. Sarnples of all three of these catalyst and formaldehydetreated fabrics were then pressed in a platen press at 350 F. for 3 minutes. As a further control, samples of the fabric containing the zinc chloride alone were also cured under the same conditions. After conditioning, the Monsanto CRA (warp only) for each was determined. The samples containing no formaldehyde exhibited a CRA of The samples on which the formaldehyde had been sprayed exhibited a CRA of 131. The samples loaded with encapsulated fonnaldehyde (5 percent) exhibited a CRA of ll6and the samples loaded with encapsulated formaldehyde (10 percent) exhibited a CRA of 132. From these results it will be apparent that the formaldehyde applied in encapsulated form was substantially equally as effective as the sprayedon formaldehyde in the crosslinking of cotton in the presence of a catalyst.
Imparting durablepress characteristics to fabrics containing natural fibers, such as cotton, by straight formaldehyde crosslinking of such fibers is a highly desirable procedure heretofore not adaptable to delayedcure operations because of the volatility of the formaldehyde. The present invention provides such adaption and thus makes available to delayedcure operations the advantages, including low cost and absence of chlorine damage problems, which are inherent in straight formaldehyde crosslinking procedures.
When the walls of the capsules containing formaldehyde or any other highly volatile material are porous they would be impractical for delayedcure use but, as established above, they may be coated with wax which not only makes them practical for such use but also makes it possible to apply them to the fabric in an aqueous padding bath if so desired. It is also within the scope of this invention to use for encapsulation of formaldehyde and other volatile materials other encapsulating materials or techniques or other capsulecoating materials or techniques in accordance with the principles already discussed herein in connection with the encapsulation of resins and catalysts.
The encapsulated formaldehyde may also be incorporated on the fabric in combinations other than the straight formaldehyde cross-linking operation just described. For example the fabric may be impregnated with nitrogenous material reactive with formaldehyde to form a resin cross-linking system when the formaldehyde is released from the capsules. Examples of such are urea, cyclic ethylene urea, other imidazolidone derivatives, cyclic propylene urea, glyoxal diurein, amides, diamides, hydantoin, urons, triazones, alkoxy urethanes and the like. When urea is used in combination with the encapsulated formaldehyde an exceedingly inexpensive way of crosslinking the fabric with resin is afforded. Here again the encapsulation of the formaldehyde eliminates the problems of odor and chemical loss during the storage periods and conversion operations which precede the delayedcure step. For use in the present invention a material such as formaldehyde may be encapsulated in gaseous from, as well as in the form of an aqueous solution.
While the most evident advantages of the present invention lie in the field of delayedcure procedures there are advantages which may be realized in connection with conventional procedures, in which the cross-linking or curing is performed by the fabric manufacturer or finisher while the fabric is still in the form of a continuous length. Under such procedures the creaserecovery behavior of the fabric is established while the fabric is in smooth flat form whereby upon subsequent storage in rolls or bolts there is very little likelihood of the setting of the fabric in wrinkled or unwanted creased condition. By encapsulating an unstable or volatile resin or other cross-linking agent, such as formaldehyde in solution or gaseous form, or by encapsulating an extremely active or volatile catalyst, such as an aqueous solution of HCl or by encapsulating both, the fabric manufacturer or finisher may realize direct or indirect advantages from the present invention. Direct advantages include use of crosslinking materials and/or catalysts which are lower in cost or which react more quickly or at lower temperatures. Indirect advantages include the ability to confine odorous operations to isolated portions of the plant. Thus, encapsulated formaldehyde will give off no odors in the padding bath or in the fabric dryers as it would if not encapsulated, and the problem of odor will only arise when the capsules are ruptured at the time the fabric is crosslinked. By providing separate ventilation for the area of the plant in which crosslinking is performed, danger of contaminating the atmosphere of other portions of the plant will be obviated. An extremely active catalyst for various resins or other cross-linking material may cause such rapid curing of the resin or other material as to shorten padding bath life to an impractical extent. By encapsulating such a catalyst, for example, an aqueous solution of HCl or some acidic gas, and using such encapsulated material in the padding bath in accordance with the present invention, padding bath life may be greatly lengthened.
It is further within the scope of the present invention to encapsulate other cross-linking resins or materials the encapsulation of which is advantageous for reasons other than those so far discussed. For example certain crosslinking reactants including epoxyresins are so reactive that they will crosslink various fibers, sometimes without a catalyst. 50- called epoxy resins are known to impart very desirable durablepress characteristics to fabrics containing natural, or otherwise reactive fibers. However, such a reactant or resin usually will react with water and consequently does not have a satisfactory padding bath life for use in aqueous baths. In accordance with the present invention such reactants or epoxy resin materials may be encapsulated in a suitable encapsulating material and can be used in aqueous padding baths with assurance of adequate padding bath life. For example, encapsulated epoxy resins may be applied to the fabric in any desired aqueous padding bath to serve either as the sole crosslinking agent or as an ingredient related with the crosslinking reaction, with or without other fabric treating or improving materials. When the fabric is thus sensitized with the encapsulated epoxy resin the crosslinking operation may be performed in the conventional manner by the fabric manufacturer or the crosslinking operation may be performed in accordance with delayedcure procedures after storage and manufacture of gannents or other products. In either event release of the epoxy resin from the capsules for the crosslinking reaction may be effected by the application of heat and/or pressure as is the case in the various examples already given.
The terms natural fiber and reactive fiber" have been used herein in the description of various embodiments of the present invention. However, it should be pointed out that the term reactive fiber is the broader term which includes the natural" fibers. By reactive fibers is means natural or synthetic fibers containing functional groups such as hydroxyls, amides, carboryls, urethanes and the like, with which known polyfunctional chemical reactants can react and thus give rise to cross-linking. Examples of some reactive fibers include the natural fibers, that is, cotton, regenerated cellulose (the various forrns of rayon), linen, hemp, ramie, jute, as well as polyvinyl alcohol and secondary acetate, all of which are reactive because they contain pendant hydroxyl groups. Other fibers which are reactive have different reactive groups, either pendant or in the chain, for example, nylon and wool both contain amide groups in the chains while spandex fibers contain urethane linkages, among others. Suitable reactants for crosslinking the various reactive fibers include aminoplasts, epoxies, diisocyanates, diacid chlorides, dianhydrides and the like, with or without suitable catalysts.
As will be apparent textile fabrics, which may be either knitted or woven, may be made wholly from a single type of reactive fibers (for example, all cotton) or a blend of reactive fibers (for example cotton and a polyamide) or a blend of reactive and nonreactive fibers (cotton and a polyester). The present invention is applicable to all such textile fabrics so long as they contain enough reactive fibers that the crosslinking of such reactive fibers will impart to the fabric a useful or significant effect such as wrinkleresistance, creaseretention and the like.
What is claimed is:
1. In a process of applying a crosslinking agent to a textile fabric, the improvement which comprises applying said crosslinking agent to said fabric in the form of microcapsules comprising discrete quantities of said cross-linking agent enclosed within walls of encapsulating material for the purpose of inhibiting the crosslinking of said fabric prior to subjecting said to conditions capable of releasing said encapsulated material.
2. In a process of sequentially or simultaneously applying a crosslinking agent and a catalytic agent to a textile fabric, the improvement which comprises applying at least one of said agents to said fabric in the form of microcapsules comprising discrete quantities of agent enclosed within walls of encapsulating material for the purpose of inhibiting the cross-linking of said fabric prior to subjecting said to conditions capable of releasing said encapsulated material.
3. In a process of applying a crosslinking agent to a textile fabric and thereafter forming said fabric into a textile article having a desired configuration, the improvement which comprises applying said cross-linking agent to said fabric in the form of microcapsules comprising discrete quantities of said crosslinking agents enclosed within walls of encapsulating material for the purpose of inhibiting the crosslinking of said textile article prior to subjecting said to conditions capable of releasing said encapsulated material.
4. The process of claim 3 wherein the textile article formed is a garment.
5. In a process of sequentially or simultaneously applying a crosslinking agent and a catalytic agent to a textile fabric and thereafter forming said fabric into a textile article having a desired configuration, the improvement which comprises applying at least one of said agents to said fabric in the form of microcapsules comprising discrete quantities of agent enclosed within walls of encapsulating material for the purpose of inhibiting the crosslinking of said textile article prior to subjecting said to conditions capable of releasing said encapsulated material.
6. The process of claim wherein the textile article formed is a garment.
7. In a process of applying a crosslinking agent to a textile fabric and thereafter subjecting said fabric to crosslinking conditions, the improvement which comprises applying said crosslinking agent to said fabric in the form of microcapsules comprising discrete quantities of crosslinking agents enclosed within walls of encapsulating material.
8. A process of claim 7 wherein crosslinking is conducted under conditions of elevated temperature.
9. In a process of sequentially or simultaneously applying a crosslinking agent and a catalytic agent to a textile fabric and thereafter subjecting said fabric to cross-linking conditions, the improvement which comprises applying at least one of said agents to said fabric in the form of microcapsules comprising discrete quantities of agent enclosed within walls of encapsulating material.
10. The process of claim 9 wherein crosslinking is conducted under conditions of elevated temperature.
1 1. In a process of applying a crosslinking agent to a textile fabric and thereafter forming said fabric into a textile article having a desired configuration and subjecting said article to crosslinking conditions, the improvement which comprises applying said crosslinking agent to said fabric in the form of microcapsules comprising discrete quantities of cross-linking agent enclosed within walls of encapsulating material.
12. The process of claim 11 wherein crosslinking is conducted under conditions of elevated temperature.
13. The process of claim 11 wherein the textile article subjected to crosslinking conditions is a garment.
14. In a process of sequentially or simultaneously applying a crosslinking agent and a catalytic agent to a textile fabric and thereafter forming said fabric into a textile article having a desired configuration and subjecting said article to crosslinking conditions, the improvement which comprises applying at least one of said agents to said fabric in the form of microcapsules comprising discrete quantities of agent enclosed within walls of encapsulating materials.
15. The process of claim 14 wherein crosslinking is conducted under conditions of elevated temperature.
16. The process of claim 14 wherein the textile article subjected to crosslinking conditions is a garment.
17. A textile fabric produced by the process of claim 1.
18. A textile fabric produced by the process of claim 2.
19. A textile article produced by the process of claim 3.
20. A textile article produced by the process of claim 4.
21. A garment produced by the process of claim 5.
22. A garment produced by the process of claim 6.
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|US6761220||Feb 1, 2002||Jul 13, 2004||Halliburton Energy Services, Inc.||Treatment of a well with an encapsulated liquid and process for encapsulating a liquid|
|EP1449911A1 *||Feb 18, 2003||Aug 25, 2004||Cognis Iberia, S.L.||Aqueous compositions containing microencapsulated active components|
|U.S. Classification||8/115.58, 8/185, 8/115.7, 8/127.5, 8/116.4, 8/115.59, 8/115.67, 8/184, 8/115.6, 8/186, 427/303, 428/402.22, 8/183, 427/226, 8/115.65, 8/129, 38/144, 8/115.64, 428/402.24, 8/120, 8/115.56, 8/182, 2/243.1, 8/127.6, 252/8.61|