US3801277A - Non-catalytic durable press process for treating cellulosic material using formaldehyde vapor and post-heating - Google Patents

Abstract

The dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of cellulosic material such as cotton fabrics are improved by impregnating the fabric with an aqueous solution of a monomeric compound which has at least one active hydrogen and reacts with formaldehyde, e.g., urea, exposing the impregnated fabric to an atmosphere containing formaldehyde vapors in the absence of a catalyst until a creaseproofing amount of an at least partially polymerized, substantially water-insoluble condensate (such as an amideformaldehyde condensate) is affixed to the fabric without, however, effecting any substantial amount of cross-linking with the cellulosic fiber. The thus-exposed fabric is thereafter postheated in an inert gaseous atmosphere also in the absence of a catalyst to further polymerize and cross-link the fabric.

Description

United States Patent 1191 Gamarra et al.

[ NON-CATALYTIC DURABLE PRESS PROCESS FOR TREATING CELLULOSIC MATERIAL USING FORMALDEl-IYDE VAPOR AND POST-HEATING [75] lnventors: Jose P. Gamarra, San Jose; Ronald Swidler, Palo Alto, both of Calif.

[73] Assignee: Cotton, Incorporated, New York,

22 Filed: July 13, 1972 21 AppljNo; 271,237

- [52] US. Cl 8/182, 2/243, 8/115.7,

8/187, 8/189, 8/194, 8/DIG. 4, 8/D1G. 9,

' S/DIG. 10, 8/DIG. 21, 28/144 51 Int. Cl...l) 0 6m 13 14, ooe 13/40, D06 13/54 [58] Field ofSearch 38/144; 2/243;8/'116.4; 8/182,184,185,186,187,189,194

[56] References Cited UNITED STATES PATENTS 3,545,913 12/1970 Joarder et al 8/116.4 3,653,805 4/1972 Gamarra et al.... 8/116.3 3,663,158 5/1972 Brenner et al. 8/1 16.4

OTHER PUBLICATIONS Joarder et al., Textile Research Journal 37,

Joarder et al., Textile Research Journal, 39, 49-54 (1969). 4

1451 Apr. 2,1974' Chemical Abstracts, 58, 9268 Gagliardi et al., Textile Research Journal, 36, l68-177 (1966).

Mehta et al., Journal of the Textile Institute, 58, 279-292 (1967).

Primary Examiner-George F; Lesmes Assistant Examiner-J. Cannon Attorney, Agent, or FirmBurns, Doane, Swecker Mathis [57] ABSTRACT fiber. The thus-exposed fabric is thereafter postheated in an inert gaseous atmosphere also in the absence of a catalyst to further polymerize and cross-link the fabric. 1 1

9 Claims, No Drawings NON-CATALYTIC DURABLE PRESS IROCESS FOR TREATING CELLULOSIC MATERIAL USING FORMALDEHYDE VAPOR AND POST-HEATING BACKGROUND OF THE INVENTION In recent years, various methods have been devised for treating cellulosic fiber-containing products such as cloth made of cotton or cotton blends in order to impart durable wrinkle resistance and smooth drying characteristics thereto. For example, cellulosic materials have been cross-linked with formaldehyde in the presence of a number of various catalysts giving durable cross-links having good resistance to repeated laundering and also to various acids and alkalies and chlorine bleaches.

US. Pat. No. 3,653,805, for example, discloses impregnating the cellulosic material with a formaldehydereactive compound, such as urea and then contacting the impregnated fabric with formaldehyde vapors to form an insoluble reaction product on the fabric in the to a gaseous catalyst and cured to give a durable press product.

Indeed,'many of the prior art processes relating to durable press products using formaldehyde or formaldehyde-reactive materials have involved the use of acidic catalysts such as sulfur dioxide, formic acid, acetic acid, zinc chloride and the like. While these catalysts are effective in causing cross-linking or curing of the materials, they may degrade the physical properties of the cellulosic material.

The use of an uncatalyzed method for producing a durable press product has been attempted in the prior art, but no commercially suitable process has heretofore been found insofar as extremely long reaction times, e.g., hours, were required to even approach acceptable minimum durable press property levels. See, for example, An Uncatalyzed, Vapor-Phase Cross-linking Reaction of Cotton Cellulose with Formaldehyde, Joarder et al., Textile Research Journal, 39, No. 1, pp. 49-54 (January, 1969).

Therefore, the search has continued for a relatively rapid non-catalytic process able to give rise to an improved balance between physical properties and durable press properties for cellulosic materials such as cotton fabric.

SUMMARY OF THE INVENTION Accordingly, a primary object of the present invention is to provide a noncatalytic durable press process for treating fiber-containing cellulosic materials which process substantially prevents or alleviates the problems mentioned above.

A more specific object is to provide a non-catalytic process which imparts an improved balance of durable press and physical properties to cellulosic materials.

Another specific object is to provide a non-catalytic durable press process for use with cellulosic materials which produces improved wrinkle resistance and smooth drying characteristics, keeps any loss of tensile strength and abrasion resistance to a minimum, and requires relatively short processing time.

These and other objects, as well as the scope, nature and utilization of the invention will become more clearly apparent from the following more detailed description. Unless otherwise indicated, all proportions and percentages of materials or compounds are expressed on a weight basis throughout this specification and appended claims. 1

in accordance with the present invention, a noncatalytic process is provided for improving the dimensional stability, wrinkle resistance, smooth-drying characteristics and total shape retentivity of a cellulosic fiber-containing fabric which comprises: (a) applying to the cellulosic fiber-containing fabric a catalyst-free aqueous solution of a monomeric compound which has at least one active hydrogen and reacts with formaldehyde; (b) exposing the impregnated fabric to an atmosphere containing formaldehyde vapors in the absence of a catalyst'until a creaseproofing amount of an at least partially polymerized condensate of the monomeric compound and formaldehyde in substantially water-insoluble form is affixed on said fabric without effecting any substantial amount of cross-linking with the cellulosic fiber; and (c) post-heating said fabric in an inertgaseous atmosphere in the absence of a catalyst at a temperature of from about C. to about C. for from about 1 to about'20 minutes to further polymerize and cross-link the fabric.

The essence of the present invention is the discovery that by post-heating in the absence of a catalyst or formaldehyde a fabric which has been impregnated with a catalyst-free aqueous solution of a monomeric compound which has at least one active hydrogen and reacts with formaldehyde, such as urea, and then exposed to formaldehyde vapors (again in the absence of a catalyst), a substantially improved wrinkle' resistance and a significantly reduced overall processing time are achieved with only minimal degradation of physical properties. Heretofore it has been thought that a catalyst must be padded onto the fabric, either throughvan aqueous padding bathor by vapor padding, in order to achieve acceptable durable press properties and processing times. The present invention has achieved these goals without adding these catalysts to the system, thus avoiding sacrificing of significant losses in physical properties of the material.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is useful for treating various natural or artificial cellulosic fibers alone or in mixtures with each other in various proportions or as mixtures with other fibers. Such natural cellulosic fibers useful herein include, for example, cotton, linen, flax, hemp and jute. Useful regenerated or artificial cellulosic fibers include viscose rayon and cuprarnmonium rayon. Other fibers which may be used in blends with one or more of the above-mentioned cellulosic fibers are, for example, cellulose acetate, polyamides, polyesters, polyacrylonitrile, polyolefins, polyvinyl chloride, polyvinylidine chloride and polyvinyl alcohol fibers. .Such blends preferably include at least about 15 percent by weight and most preferably at least about 35 percent by weight of cotton or other cellulosic fibers.

A fabric may be knit, woven or non-woven, or be any otherwise constructed fabric. The fabric may be flat,

creased, pleated, hemmed or sewn or otherwise formed to produce an article such as a garment of any desired shape prior or subsequent to contact with the reactive vapor phase containing formaldehyde. After processing,'the formed cross-linked fabric will maintain substantially the original configuration for the life of the article, that is, a wash-wear or durable press fabric will be produced. I

In accordance with the present invention, the cotton or cellulose-containing fabric is impregnated with a catalyst-free aqueous solution containing a monomeric compound which has at least one active hydrogen and reacts with formaldehyde, e.g., a compound of the amide type.

Suitable amide-type, reactive with formaldehyde compounds are typically water-soluble and include various ureas such as urea, butyl urea, ethylene urea, cyclic propylene urea, allyl urea, cyclic dihydroxyethylene urea, cyanuramide (melamine), thiourea as well as formamide, acetamide, maloamide, acrylamide, the lower. alkyl (e.g., C C or hydroxyalkyl carbamates, such as ethyl carbamate and-hydroxyl ethyl carbamate, aryl sulfonamides, such as benzene-sulfonamide or p-benzene-disulfonamide, the lower (e.g., C C alkyl sulfonamides or bis-sulfonamides such as methane-, ethane-, n-butaneor isobutane-sulfonamide, methylene-bis-methane-sulfonamide, ethylene-bismethane-sulfonamide, l,3-propane-bis-methane sulfonamide and so on. Urea and ethyleneurea are preferred.

It is particularly advantageous to impregnate the fabric with the aqueous solution of the amide compound was to produce adry add-on of between about 0.5 and 25, preferably between about 2.5 and l5,,percent by weight of the fabric.

The amide compound is preferably applied in an aqueous solution which may havea pH of from about 4 to 12. Generally, the aqueous solution will have an alkaline pH. Often, the pH will be between above about 7 and less than about ll, preferably between about 8 cent, preferably'from about 3 to about 20percent, most preferably from about to about 15, percent of theamide.

Pretreatment of the fabric; prior to the exposure to the formaldehyde vapors, with polymeric resinous additives that form soft films such as conventional disperand 9, and containing from about 1 to about 25 perpreferably from about 3 to about 65, most preferably from about 5 to about 15, percent by weight of the dry cellulosic fabric material.

if desired, the impregnated fabric may be dried and then used in garment manufacture (e.g., cutting, sewing and pressing) either immediately or after shipment to a different location or after storage of indefinite duration. The resulting garments may then be further treated as described hereinbelow either immediately or after storage of indefinite duration. The impregnated fabric (or garment) is exposed in the absence of a catalyst to an atmosphere containing formaldehyde vapors until a crease-proofing amount of an at least partially polymerized condensate of the monomeric compound and formaldehyde (e.g., a partially polymerized ureaformaldehyde condensate) in substantially waterinsoluble form is affixed on the fabric without, however, effecting any substantial amount of cross-linking with the cellulosic fiber.

Although there is no substantial cross-linking, there apparently may be some binding, such as grafting of the condensate onto hydroxyl groups of the cellulose, taking place during the formaldehyde vapor contact step. A crease-proofing amount of the at least partially polymerized condensate is that amount which, when the fabric is post-heated, yields a fabric having acceptable durablepress properties.

The atmosphere of the reaction zone may also contain air or any other non-acidic and non-deleterious gas which does not react with the formaldehyde or the monomeric compound .and does not catalyze their reaction. Often, the reaction zoneatmosphere contains from about 1 to about 100, preferably about 30 to about 95, volume percent formaldehyde.

Contact of the impregnated fabric with the formaldehyde vapor-containing atmosphere can be performed at a temperature of from about 100C. to about l60C.,

maldehyde vapor-containing atmosphere may be emsions or latices, can result in unusually great incremental improvement in wrinkle recovery of the treated fabric. Polymer additives can also improve the flex, abrasion resistance, and tear strength, or alter the ratio of dry wrinkle recovery to wet wrinkle recovery, or in some instances, shorten the reaction time needed to produce an acceptable durable press fabric. Polymeric additives suitable for such purposes are, in most cases, available commercially in concentrated aqueous latex forms, and it is desirable to dilute these to a concentration of about 1 to about 30, often from about 5 to about ployed. For example, a batch system utilizing a closed vessel 'ortube containing the reactive vapor phase atmospheremay be used into which the impregnated monomer-containing fabric may be placed and there exposed to the atmosphere for the appropriate time. In the alternative, a dynamic or continuous system can be used such as one wherein a gas stream containing formaldehyde vapor is passed through a closed elongated chamber through which the impregnated fabric or articles are also passed at an appropriate rate either concurrently or countercurrently relative to the. gas. It is also possible to use combinations of the above, that is, such as by-passing a stream containing formaldehyde vapors over a stationary fabric. 7

The required formaldehyde vapor may be generated in any convenient manner, such as by heating a suspension of paraformaldehyde in mineral oil to generate formaldehyde gas which is then metered into the treating chamber. The formaldehyde vapor will be present in the reaction zone in an amount at least sufficient to react with all of the amide compound and generally will be present in an excess of that amount.

Typically, at the end of the formaldehyde vapor contacting step, the fabric is desirably heated at a temperature above about 80C., e.g., in the range of from about 100C. to about 180C., preferably from about 140C. to about 160C. for from about 1 to about 20 minutes, preferably from about 3 to about minutes, to further polymerize and cross-link the fabric thus improving its durability to laundering as well as improving the durable press characteristics of the treated fabric. in addition, this post-heating step will volatilize and remove any water vapor, unbound formaldehyde and other volatile residues. This post-heating step may also allow a reduction in the time of exposure to the formaldehyde vapor without sacrificing durable press performance. Heating the treating fabric may advantageously be performed in any suitable fabric heating chamber.

The treated fabric may be subjected to the postheating step immediately after being exposed to the formaldehyde vapors or it may be stored for an indefinite period of time. If desired, the fabric may be used in garment manufacture after exposure to formaldehyde vapors and before the post-heating step. The treated fabric is preferably not washed prior to the post-heating step. Although we do not wish to be bound I by theoretical considerations, it would appear that the least. partially polymerized condensate formed in the formaldehyde vapor contact step may contain some re- 2 pounds, respectively).

active groups (such as methylol groups), the reactivity of which may be reduced by washing with water. The efficiency of the overall process is thus considerably reduced when the fabric is washed between these steps.

. The invention is additionally illustrated in connection with the following examples which are to be considered as illustrative of the present invention. It should be understood, however, that the invention is not limited to the specific details of the examples.

EXAMPLES The reactor used in work was a cylindrical vessel having a capacity of about7l liters constructed of one- /eighth inch aluminum (42 cm. inside diameter and 57 cm. high). The walls of this reactor were heated with 1 band heaters equipped with a 3-way switch which perwas preferred.

Formaldehyde gas was conducted into the reactor through heated lines from a separate vessel where it was generated as needed by heating a suspension of between about 30 to percent by weight (unless otherwise indicated) of paraformaldehyde in mineral oil. The reactor was further equipped with another line through which other gases such as air may be admitted when and as desired. The rate of flow of formaldehyde was controlled by regulating the temperature of the mineral oil between and 140C.

Unless otherwise indicated, all samples were tested wrinkle recovery angle in accordance with the test methods described in AATCC 66-1959T. For Elmendorf Tearing Strength, test methods are in accordance with ASTM D-l424-59 and for Stoll Flex Abrasion Resistance, the test. methods are in accordance with ASTM-D-61T (using head and tension loads of k and EXAMPLE 1 Samples of 100 percent cotton twill fabric (112 X 50 thread),were padded with aqueous solutions containing from 0 to 20 percent urea and 10 percent (solids).urethane latex E-502 (Wyandotte Chemical Corporation) to give various add-ons. The impregnated samples were each dried to a moisture content of about 7 percent, exposed to a gaseous formaldehyde vapor atmosphere for 2 minutesat C. and post-heated in air for 5 minutes at 150C. Unless otherwise indicated, fabric samples in allof the examples were post-heated immediately after exposure to the gaseous formaldehyde atmosphere. i

As shown in Table 1, fabric properties were considerably improved when padded with a 1 percent ureacontaining solution (about 2.6 percent monomer addon calculated as the total add-on, Table 1, minus the add-on value of polymeric additive for 0 percent urea, i.e., 4.1 weight percent) as compared with the 0 percent urea-containing solution. These improved properties were generally maintained or improved with each of the aqueous solutions having increased urea concentrations.

Table 1 indicates that as little as 1 percent urea in the aqueous solution imparts good durable press properties tocotton fabrics in the present process. These results are to be contrasted with conventional catalyzed durable press processes in which aqueous solution concen- TABLE I Tensile properties Wrinkle recovery angle Tearing Stoll Warp Fill (degrees) strength fiex Urea concen- Add- (Elmendorf abra- Work- Exten- Work- Extentration in on, Dry Wet units) sion tosion at Breaking tosion at Breaking Bending impregnating perwarp rupture reek, strength rupture break, strength strength solution cent Warp Fill Warp Fill Warp Fill (cycles) (in.-lb.) percent (lb (in.-1b.) percent (lb (0111. 4.1 119 108 136 122 164.8 108. 8 933 35. 6 18. 9 180. 5 12. 3 19. 4 71. 3 6.7 146 129 157 142 218. 0 116.0 1, 175 18.1 13.9 125. 5 6. 6 14. 4 48. 6 5. l 6.8 150 144 212. 5 122. 5 1,338 18. 2 13. 6 125.0 6. 5 14. 2 50. 0 5. 0 7. 4 152 132 155 138 237. 5 127.0 1, 310 20. 1 14. 6 137.0 6. 7 14. 5 52. 3 5. 0 8. 1 155 136 156 144 213. 5 124. 2 1, 462 22. 2 14. 2 144. 0 6. 1 15. 2 47. 4 5. 2 10. Z 152 136 152 142 201.0 112.0 1, 465 19. 6 13. 4 133.5 6. 3 15. 1 49. 5 5. 3 19. 5 154 148 169 154 129. 0 84. 8 626 15.6 9. 8 137.0 4. 8 12. 6 48. 3 5. 4 23. 9 147 144 166 149 134. 3 83. 2 754 19. 4 10. 7 155. 5 7. 2 13. 9 59. 7 5. 6 N.a. 74 75 73 81 169. 4 98. 3 421 31. 8 13. 2 187.0 11. 8 17. 9 71. 6

Untreated control.

EXAMPLE 11 The effect of formaldehyde exposure time and the presence of steam on fabric properties wasstudied in this Example in which samples of the fabric of Example I were impregnated with an aqueous solution containing 10 percent urea and 10 percent (solids) urethane latex E-502, exposed to formaldehyde vapor for from 1 to 4 minutes at 120C. in the presence or absence of any steam and then post-heated for 5 minutes at 150C. The resulting fabric properties shown in Table II indicate that small increases in wrinkle recovery angle and corresponding decreases in tensile strength were obtained as exposure time was increased from 1 to 4 minutes.

. 8 teria 9112811 090 i 19.@E LEEEPQEFEQ;

The effect of post-heating temperature is shown'in Table lll-B. Although theamount of amide add-on increased with increased temperature, most other properties did not. After 10 laundering cycles, the fabric properties showed little change, indicating that the process of this invention can be operated within wide ranges of post-heating time and temperature without significantly affecting the balance of fabric properties. It is known that gaseous formaldehyde generated by heating paraformaldehyde-mineral oil slurries may contain a minor amount (i.e., less than 5 weight percent) of impurities such as water, methanol, methyl for- TABLE 11 V Tensile properties HCHO Wrinkle tii-ecovegy angle geariggh St E Warp Fill t ees s ren I HCHO exp o r fe Addegr (Elmendori flex Work- Exten- Work- Extenexposure time at on, Dry Wet units) abrasion t0- sion at Breaking tosion at Breaking time at 120 120 C. perwarp rupture break. strength rupture break, strength C. (min.) (min) cent Warp Fill Warp Fill Warp Fill (cycles) (in-lb.) percent (1b.) (in-lb.) percent (1b. 0 11.8 150 130 147 142 102.7 98.8 1,234 19.5 11.5 147.5 0.2 14.8 51.0 0 13.7- 154 142 150 145 157.5 90.0 1,035 17.3 11.0 137.0 5.8 13.4 40. 0 3 iii it? it; 1% ii $38 23% ii? iii 1%?) 2'3 3'3 238 1 1310 152 142 158 145 146:8 86:0 050 1713 1110 13715 :2 14:0 44:0 '2' 14.0 152 145 154 152 148.5 87.5 811 15.8 10.8 131.0 5.3 14.0 48.0 3 23 ii? iii iii 33% Z1 3? 5 4% iii l'i il'fi 2'3 iii 23% 4 14.3 1 57.4. Na. 74 75 73 81 150.4 9.3 421 31.8 13.2 187.0 11.8 17.9 71.0

Untreated control. W WWW V V M H VY ;W V v 7 EXAMPLE lll foruse in catalyticallyeffective amounts in durable press processes using formaldehyde. However, the Samples: the fabilc of Exarilgle I which were 1m small amount of formic acid which could (depending pregnated w1th solutions containing percent urea upon the, g purity) be present in the process f the and percent (s dfQglreth lane latex E302, drleg :0 present invention is so small as to 5515451551551 to a moisture content 0 a percent 3 expose o cause any significant change in the balance of properformaldehyde .vapor for 2 mmutes i L 22 ties obtained as compared with those obtained when heated varying terffpelames. an nmes e a carrying out the reaction in the absence of any catalytic shown in Table Ill-A 1nd1cates that although the tensile material That is the Small amoum'of formic acid or a a J Strength remains essennauy unchanged}; the f other material normally considered a catalyst in adurawet f recovery angles a .ble press process includingformaldehyde which could creased m post'heated i z as compam wit a I be present inthe process of the'present invention is less' Sam much 1. s eat? v than a catalytically effective amount and so small as to Thus, although the theoretical mechanism is not be insufficient to cause any significant change in the clear, itappears that further condensation probably oc- 4 5 balance of properties obtained as compared with those curs between urea and formaldehyde during the postobtained when carrying outthe reaction in the absence heating step and also that further bonds may be formed of any amount of a material normally considered a catbetwe en the urea-formaldehyde resin and the cellulosic alyst. 4mm 7 A v TABLE 111-14 Tensile properties I Warp Fill Wn'nkle (gecovegy Angle Ttearh: 830311 E i. E :8

recs 5 reng X X 8D- x 11 Post heating Add- 6g w (Elmendorf abrawort'kosior; B ah W012i; $0111; B an ti t Numb r on, D et units slon 3. re 'ng a re 'ng me a e perry wra rupture break, strength rupture break, strength washings cent Warp Fill Warp Fill Warp Fill (cycles in.-lb.) percent (1 (in-lb.) percent (1b.)

1 8. 9 133 117 141 137 255. 0 153. 5 888 28. 0 10. 0 153. 5 5 1s. 4 54. 5 1 11.0 143 122 152 140 109.5 126.8 1,054 21.0 13.4 138.5 7.3 15.0 53.1 1 11.9 148 134 158 151 109.3 115. 1,508 23.2 13.4 151.0 7.3 15. 2 53.0 1 12.0 152 138 132 149 178.0 115. 1,428 21.4 13.0 147.0 7.2 15.2 53.4 1 13.9 155 140 150 151 152.0 97. 1,161 11.7 114 135.0 0.1 14.8 50.2 1 13.3 155 150 158 157 159.8 95. 1,080 19.3 11.8 142.0 5.3 13.8 47.2 10 8.0 138 122 142 255.0 143. 558 23.9 15.5 141.5 8.4 15.4 57.2 10 9.1 140 122 150 210. 5 131. 732 21.4 14.0 140.5 7.8 15.5 55.4 10 9.9 148 133 151 142 193.5 124. 1,214 20.9 13.8 141.5 7.5 15.2 50.0 10 10.0 150 134 142 202. 5 120. 1,210 20.9 13.2 142.5 7.8 15.4 500 10 11.8 154 135 157 144 151.0 100. 1,275 17.3 12.2 133.0 5.2 14.4 45.0 10 11. 7 152 158 140 150.8 113. 1,159 18. 3 12.4 134.0 59 14.0 49.7 N.a. Na. 74 75 73 81 159.4 98. 421 31.8 13.2 187.0 11.8 17.9 71.8

Untreated control.

m e a @0219 388 f m ssidii 3 5998883 0 TABLE III-B f Tensile properties War Fill Wrinkle Recovery Angle 'Ieerin Stoll p (degrees) strengt flex Exten- I Exten- Add- (Elrn endorl abra- Workslon Workslon Post heating Number on, Dry Wet units) slon t tob it Breelrln toat Breekln perwrap rup ure ree stren t ru ture break, etr n t temp. C.) washings cent Warp F111 Werp Fill Warp Fill (cycles) (ln.-lb.) percent (1 1).) (ln l-lb.) percent h.) 1 11.6 143 136 150 148 177.0 113.0 18.6 13.4 132.0 7. 3 l5. 1 11. 5 153 140 154 147 163. 7 101. 18. l2. 4- 136. 5 6. 5 14.2 7 1 12. 7 158 141 154 152 145. 7 92. 8 979 17. 4 11. 6 136. 0 5. 5 13. 2 41). 2 1 13. 1 159 148 153 156 134. 8 86. 8 890 16. 7 11. 0 137. 0 5. 4 13. 2 48. 5 11. 6 142 122 149 142 173. 0 117. 5 21. 3 14. 8 139. 5 6. 7 15. 7 1. 3 10 11. 6 152 134 158 146 151. 2 97 0 19. 1 11. (i 141. 0 6.1) 15. 4 58. 2 10 12. 4 150 134 153 146 152. 8 92 2 874 17. 8 12. 4 136. 5 5. 4 13. 6 48. 0 10 12. 6 155 138 153 149 150. 0 92. 0 1, 006 17. 2 11. 8 136.0 5. 5 13.4 50.0 N.a. N.a. 74 75 73 81 169. 4 98. 3 421 31. 8 13. 2 187. 0 11. 8 17. 9 71. 6 Untreated control.

. EXAMPLE IV EXAMPLE V The effects of the moisture content of the cotton fabric prior to formaldehyde treatment were studied. Samples of the cotton twill fabric of Example I were padded with a solution containing 10 percent urea and 10 percent (solids) urethane latex E-502, dried and conditioned to various levels of moisture content, exposed to formaldehyde vapor for 2 minutes at 120C. and then post-heated for 5 minutes at 150C. g

It is known that in at least some prior art catalytic processes increasing the moisture content of cotton fabrics prior to treatment with formaldehyde vapors increases the amount of absorbed formaldehyde as well as the amount of fixed formaldehyde. In the present process, however, the amount of water in cotton fibers does not appear to be a critical parameter in determining the extent of reaction between formaldehyde and urea. As shown in Table IV, add-ons for all samples 35 were approximately equal and all fabric samples had acceptable durable press properties.

The effect of surface polymeric additives on wrinkle recovery angle and strength loss was studied by impregnating samples of the fabric of Example 1 with aqueous solutions of various commercially available polymeric additives with and without urea also being present in the aqueous solutions. The impregnated fabric samples were each dried at C. to a' moisture content of about 7 percent,'exposed to formaldehyde vapor for 2 minutes at C. and post-heated for 5 minutes at 150C. Results are shown in Table V. As expected, fabrics impregnated with the. stronger (higher film modulus value) polymeric additives such as Rhoplex K -87 and urethane latex P -50l generally show greater strength and lower wrinkle recovery angles than the fabrics impregnated with the lower strength polymeric additives Rhoplex K-14 and urethane latex E-502.

E MBLE TABLE IV Tensile properties Warp Fill Wnnkle recovery angle Tearm Stoll (degrees) strengt flex Exten- Exten- Initial No. (Elmendorf abra- Werksion Worksion moisture of Dry units) sion toat Breaking toat Breaking Add-on, content, weshwarp rupture break. strength rupture break, 1 strength percent percent ings Warp Fill Warp F111 Warp Fill (cycles) (in-lb.) percent (1b.) (1n.-lb percent (15.) 11.3 3. 5 1 150 132 152 144 179. 0 141 2 1, 886 24. 0 14. 8 145. 5 8. 2 15. 6 51. 6 11.4 7. 2 1 161 150 159 155 139. 8 87 5 932 15. 2 10. 6 129. 5 5. 4 13. 5 47. 2 11.8 16. 0 1 158 152 167 153 135. 2 84. 0 847 16. 2 11. 0 131. 5 5. 8 13. 8 50. 9 11.4 3. 5 10 140 158 138 202. 0 158. 2 1, 866 27. 9 17. 5 148. 0 8. 6 16. 4 57. 7 11.2 7. 2 10 158 142 164 152 163. 2 99. 8 1, 258 17. 7 12. 1 131. 0 5. 5 14. 0 46. 0 11.7 16.0 10 154 169 157. 0 88. 5 1, 222 16. 3 11. 8 128. 0 5. 4 14. 0 46. 1 N.a. N.a. N.a. 74 75 73 81 169. 4 98. 3 421 31. 8 13. 2 187. 0 11. 8 17. 9 71. 6

Untreated control.

TABLE v Wrinkle Recovery Tensile Strength Additive Add-on Angle, W F (7: retention) (7! solids) (7r) (degrees) Dry Wet Warp Fill 2.5% Rhoplex K-87" 1.8(8.3 170(296) 195(292)" 90(74)" 97(66)" 5.0% Rhoplex K-87 3.1(9.7) 177(296) 204(300) 89(74) 108(71) 7.5% Rhoplex K-87 4.l(ll.l) 191(294) 206(303) 91(73) 100(70) 10.0% Rhoplex K-87 5.4( 12.8) (300) 217(301) 94(78) 95(77) 2.5% Rhoplex K-l4 1.0(7.6) l9l(265) 188(258) 79(71) 91(58) 5.0% Rhoplex K-l4 2.5(86) 206(280) 218(261) 83(68) Wrinkle Recovery Tensile Strength Additive Add-on Angle. W F (7: retention) ("/1 solids) ('72. (degrees) Dry Wet Warp Fill 7.5% Rhoplcx K-l4 2.9(9.4) 222(280) 217(283) 75(68) 83(59) 10.0% Rhoplex K-l4 4.3(! 1.6) 225(274) 235(279) 77(69) 79(66) 2.57: U. L. P'SOI 0.9(83) lli4(284) 204(274) 94(74) l()l(74) 5.09? U. L. P-SOl 2.4( 10.2) 205(288) 224(28I) 94(8l) lUl(75) 7.59? U. L. P-SOl 3.8(l2.0) 204(293) 238(296) 98(82) 98(8l) 100% U. L. P-50] 5.()( 13.4) 222(288) 254(298) 96(85) 98(78) 2.5% U. L. E-502" 2.1(64) 206(268) 222(264) 89(72) 93(76) 5.07: U. L. E-502 3.2(8.4) 214(285) 232(286) 78(77) 89(66) 7.571 U. L. E-SOZ 4.4(l().3) 235(298) 259(293) 81(72) 94(66) 10.0% U. L. E-502 5.2( 12.5) 227(302) 263(305) 82(7l) 89(69) Control n.a. 149 154 I 100 a an acrylic resin available from the Rohm and Haas Co. b-an acrylic emulsion available from the Rohm and Haas Co.

0- Urethane Latex P-50l available from the Wyandotte Chemical Corp. d Urethane Latex E502 available from the Wyandotte Chemical Corp.

e-FlgUICS in parenthesis denote values for fabric treated in the presence of urea based on the weight of pad bath).

to the foamaldehyde vapor and the post-heating step were considered inthis example.

Samples of the fabric of Example I were padded with an aqueous solution containing 10 weight percent urea and 10 weight precent urethane latexE-SOZ. The impregnated sampleswere dried to a moisture content of Angles and Durable Press Ratings as compared with the untreated control, both show unacceptable properties for commercial durable press materials. Both samples also show properties substantially less than the samples of Table Vl-A. In addition, this data shows that post-heating only moderately improves the durable about 7'percent, pressed and exposed to a 100 percent Press Properties Washed mPl Time between exposure to gaseous formaldehyde and post-heating,

TABLE Vl-A.

Wrinkle Recovery Angles, (W Durable Press Ratings F). degrees hours Dry Wet 0 292 297 4.1 l 293 310 4.1 2. 288 314 4.1 4 286 327 4.1 6 285 301 4.0 24 274 316] 4.0 72 309 315 4.0 144 299 330 4.0, Untreated Control 149 I54 I [,5

formaldehyde vapor atmosphere for 2 minutes at TABLE VLB 120C. The samples were held for varying times and I then post-heated in air at 150C. for 5 minutes. The re- Sample Wrinkle Recovery Angle Durable Press suits are shown in Table VI-A. 83+ grees ll 'leatltngs The results obtained indicate that the impregnated g fabrics were not affected by delaying the post-heating 1 230 :2? a step since the resulting properties wereessentially the Untreamg Comm] fig 1 same (and within the limits of experimental error) whether the fabric was post-heated immediately or after 6 days.

Samples of the same fabrics as above were impregnated, dried and exposed'to gaseous'formaldehyde in the same manner as above and were washed immediately after exposure to the formaldehyde vapors. Sam- 7 EXAMPLE'VH The interaction of the impregnation of the amide, im-

ple l was not post-heated. Sample ll was post-heated for pregnation of the polymeric additive and contact with 5 minutes at C. and washed again.

The results obtained are shown in Table VI-B. Although both samples show higher Wrinkle Recovery gaseous formaldehyde was considered .in-this example. The varying treatments applied to the fabric samples as well as the results obtained are shown in Table VI].

TABLE vu Pretreatment Posltreatment Formaldehyde Wrinkle Recovery Tensile Strength Exposure Angle (degrees) (/1 retention) Time'(min) Dry Wet None None I 145 172 97 5 142 164 88 ll) l 33 I66 86 15 I42 I64 99 20 I43 I70 95 1071 E-SOZ" None I90 I67 88 l 236 260 85 235 259 89 l() 246 266 86 263 284 83 252 280 82 10% Urea None 1 267 253 65 2 262 248 70 3 251 243 72 4 270 250 76 10 7r Urea 1071 E-502 l 298 285 50 2 288 277 67 3 291 279 69 4 294 280 62 10% Urea None 1 280 289 71 10% E-502 2 296 302 70 3 307 308 69 4 303 310 66 All fabrics posthealed for 5 min at 150C. I Percent solids in aqueous solutions As shown therein, samples of the fabric of Example I exposed to gaseous formaldehyde for l to 20 minutes at 120C. without prior impregnation with the mono- Y mer or the surface polymeric additive exhibited noincreases in wrinkle recovery angles (hereinafter WRAs) even after 20 minutes of treatment. These fabrics, however, sufferedtensile strength losses of l to 14 percent respectively. I

Fabrics padded with an aqueous solution containing 10 percent (solids) urethane latex E-502 exposed to formaldehyde vapor for 5 to 20 minutes and postheated for 5 minutes at 150C., exhibited moderate degrees of recovery angles (235 4 263dry and 259 280 wet), probably indicating a chemical interaction between the urethane latex, formaldehyde and cellu lose. Although the dry WRAs proved tobe nondurable to laundering, the wet WRAs were unchanged after 10 laundering cycles. The loss in tensile strength exhibited by these samples was between 1 l and 18 percent. Y

In another part of the experiment, fabrics were padded with a 10 percent urea solution, dried to a moisture content of about 7 percent, exposed to gaseous formaldehyde for l to 4 minutes at l20C.,-and post-heated for 5 minutes at 150C. These fabrics also showed only moderate WRAs but higher strength losses in fabrics treated with formaldehyde in the presence of the urethane latex alone.

To study the effect of applying the urethane latex to fabrics that had been treated with the urea formaldehyde system in the absence of-a polymeric additive, fabrics from the previous experiment were re-padded with an aqueous solution containing 10 percent solid urethane latex E-502, dried and then cured for 5 minutes at 150C. As shown in Table Vlll, the dry and wet WRAs increased by'about each while the tensile strengths decreased 3 to 10 percent. After 10 laundering cycles, most properties showed little change.

The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protected herein, however, is not to be construed as limited to the particular forms disclosed,

since these are to be regarded as illustrative rather than restrictive. Variations and changesmay be made by those skilled in the art without departing from the spirit of the invention. I

What is claimed is: I 1

1. Anon-catalytic process for improving the dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of a cellulose fiber-containing fabric which comprises:

a. applying to a cellulose fiber-containing fabric a catalyst-free aqueous solution of a monomeric amide compound which has at least one active hydrogen and reacts with formaldehyde;

b. exposing the impregnated fabric to an atmosphere containing formaldehyde vapors in the essential absence of an acidic catalyst until a crease-proofing amount of an at least partially polymerized condensateof the monomeric amide compound and formaldehydein ubsta tially water in soluble form is affixed on said fabric withiaufeffecting any sub stantial amount of cross-linking with the cellulose fiber; and v sphere in the essential absence of an acidic catalyst at a temperature of from about C. to about C. for from about 1 to about 20 minutes to further polymerize and cross-link the fabric.

2. The process of claim 1 wherein said amide is urea and further wherein said fabric is impregnated with the aqueous solution of urea so as to produce a dry add-on of en bo t 7 395 2 FBU21LW E. h fabric. 7

3. The process of claim 1 wherein said impregnated fabric is formed into a garment prior to exposure to the formaldehyde vapors.

4. The process of claim 1 wherein said impregnated fabric is dried to a moisture'content of from about 2 to about 100 percent by weight of the dry cellulosic fabric material prior to exposure to the formaldehyde vaporcontaining atmosphere.

5. A non-catalytic process for improving the dimensional stability, wrinkle resistance, smooth'drying charpost-heating said fabric in an inert gaseous atmoher-containing fabric which comprises:

a. applying to a cellulose fiber-containing fabrica catalyst-free aqueous solution .of a monomeric amide compound which has at least one'active hydrogen and reacts with formaldehyde and a polymeric film-forming additive so as to produce an impregnated fabric havingta dry add-onvof between about 0.5 and 25 percent by weight of the fabric of the said monomeric amide compound;

b. drying said impregnated fabric;

c. forming said'impregnated fabric into a garment;

d. exposing the impregnated garment to an atmosphere containing formaldehyde vapors in the essential absence of an acidic catalyst at a temperature of from about 100C. to about 160C. for from about 0.1 to about 60 minutes until a creaseproofing amount of an at least partially polymerized condensate of the monomeric amide compound and formaldehyde in substantially waterinsoluble form is affixed on said fabric without effecting any substantial amount of cross-linking wit the cellulose fiber;

e. post-heating said exposed garment in an inert gaseous atmosphere in the essential absence of an acidic catalyst at a temperature of from about .l00C. to about 180C. for from about 1 to about 20 minutes to further polymerize and cross-link the from about 3 to about 65 percent byweightof the dry cellulose fiber-containing fabric prior to exposure to 16 the formaldehyde vapor-containing atmosphere.

8. The non-catalytic process of claim 7 wherein said impregnated fabric is exposed to the formaldehyde vapors for a time of from about 0.5 to about 20 minutes.

9. A non-catalytic process for improving the dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of a cellulose fiher-containing fabric which consists essentially of the following sequential steps: r

a. applying to the cellulose fiber-containing fabric a catalyst-free aqueous solution containing from about 5 to about 15 percent by weight of the solution of urea and from about 5 to about 15 percent of a film-forming polymeric additive;

b. drying the impregnated fabric to a moisture content of from'about 5 to about 15 percent by weight of the dry cellulose fiber-coptaining fabric;

c. exposing the dried, impregnated fabric to a vapor phase atmosphere consisting essentially of formaldehyde vapors in an uncatalyzed reaction zone 7 maintained at a temperature of from about l05C.,

d. immediately thereafter post-heatingsaid fabric in an inert gaseous atmosphere inthe essential absence of an acidic catalyst at a temperature of from about C. to about C. for a time of from about 3 to about 10' minutes to further polymerize and cross-link said fabric.

Claims (8)

1. 2. The process of claim 1 wherein said amide is urea and further wherein said fabric is impregnated with the aqueous solution of urea so as to produce a dry add-on of between about 0.5 and 25 percent by weight of the fabric.
2. 3. The process of claim 1 wherein said impregnated fabric is formed into a garment prior to exposure to the formaldehyde vapors.
3. 4. The process of claim 1 wherein said impregnated fabric is dried to a moisture content of from about 2 to about 100 percent by weight of the dry cellulosic fabric material prior to exposure to the formaldehyde vapor-containing atmosphere.
4. 5. A non-catalytic process for improving the dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of a cellulose fiber-containing fabric which comprises: a. applying to a cellulose fiber-containing fabric a catalyst-free aqueous solution of a monomeric amide compound which has at least one active hydrogen and reacts with formaldehyde and a polymeric film-forming additive so as to produce an impregnated fabric having a dry add-on of between about 0.5 and 25 percent by weight of the fabric of the said monomeric amide compound; b. drying said impregnated fabric; c. forming said impregnated fabric into a garment; d. exposing the impregnated garment to an atmosphere containing formaldehyde vapors in the essential absence of an acidic catalyst at a temperature of from about 100*C. to about 160*C. for from about 0.1 to about 60 minutes until a crease-proofing amount of an at least partially polymerized condensate of the monomeric amide compound and formaldehyde in substantially water-insoluble form is affixed on said fabric without effecting any substantial amount of cross-linking with the cellulose fiber; e. post-heating said exposed garment in an inert gaseous atmosphere in the essential absence of an acidic catalyst at a temperature of from about 100*C. to about 180*C. for from about 1 to about 20 minutes to further polymerize and cross-link the fabric.
5. 6. The non-catalytic process of claim 5 wherein said amide is urea.
6. 7. The non-catalytic process of claim 6 wherein said impregnated fabric is dried to a moisture content of from about 3 to about 65 percent by weight of the dry cellulose fiber-containing fabric prior to exposure to the formaldehyde vapor-containing atmosphere.
7. 8. The non-catalytic process of claim 7 wherein said impregnated fabric is exposed to the formaldehyde vapors for a time of from about 0.5 to about 20 minutes.
8. 9. A non-catalytic process for improving the dimensional stability, wrinkle resistance, smooth drying characteristics and total shape retentivity of a cellulose fiber-containing fabric which consists essentially of the following sequential steps: a. applying to the cellulose fiber-containing fabric a catalyst-free aqueous solution containing from about 5 to about 15 percent by weight of the solution of urea and from about 5 to about 15 percent of a film-forming polymeric additive; b. drying the impregnated fabric to a moisture content of from about 5 to about 15 percent by weight of the dry cellulose fiber-containing fabric; c. exposing the dried, impregnated fabric to a vapor phase atmosphere consisting essentially of formaldehyde vapors in an uncatalyzed reaction zone maintained at a temperature of from about 105*C. to about 120*C. for a time of from about 1 to about 5 minutes, until a crease-proofing amount of an at least partially polymerized amide-formaldehyde condensate in substantially water-insoluble form is affixed on said fabric without any substantial cross-linking with the cellulose fiber; and d. immediately thereafter post-heating said fabric in an inert gaseous atmosphere in the essentIal absence of an acidic catalyst at a temperature of from about 140*C. to about 160*C. for a time of from about 3 to about 10 minutes to further polymerize and cross-link said fabric.