US3371983A - Prewetting cellulosic fabric before introduction to dehydrating solution of formaldehyde reactant in a continuous process - Google Patents

Description

March 5, 1968 R. P. BARBER ETAL 3,3 3

PREWETTING CELLULOSIC FABRIC BEFORE INTRODUCTION TO DEHYDRATING SOLUTION OF FORMALDEHYDE REACTANT IN A CONTINUOUS PROCESS Filed Dec. 4, 1961 2 Sheets-Sheet 1 INVENTOR QICHNZD P b/mbuz VEIZNOH G 5mm A'ITORNEYJ United States Patent v I 3,371,983 PIREWETTING CELLULOS IC FABRIC BEFORE IN- TRODUCTION T DEHYDRATING SOLUTION 0F FORMALDEHYDE REACTANT IN A CON- TINUOUS PROCESS Richard P. Barber, Mooresville, and Vernon C. Smith, Greensboro, N.C., assignors to Burlington Industries, Inc., Greensboro, N.C., a corporation of Delaware Continuation-impart of application Ser. No. 136,418, Sept. '5, 1961. This application Dec. 4, 1961, Ser. No. 156,859

11 Claims. (Cl. 8-1164) This application is a continuation-in-part of application Ser. No. 136,418, filed Sept. 5, 1961, now abandoned.

The present invention relates to a continuous method for treating celiulosic fabrics with formaldehyde.

While formaldehyde has been employed in the past to treat cellulosic fabric, there is need for improving both the wet and dry wrinkle recovery. Furthermore, previous reactive type treatments of cellulosic fabrics, including formaldehyde treatments, degrade the fabric to an extent of over 50%.

Accordingly, it is an object of the present invention to develop an improved continuous process for treating cellulosic materials with formaldehyde.

Another object is to improve the wet wrinkle resistance of cellulosic fabrics.

A further object is to improve the dry wrinkle resistance of cellulosic fabric.

An additional object is to improve the wrinkle resistance of;cellulosic fabrics while retaining 5060% of the tensile strength.

,Yet another object is to improve the wrinkle resistance of cellulosic fabrics by a reactive procedure while at the same time retaining 70% or more of the tensile strength of the fabric.

Still another object is to reduce the time of formaldehyde treatment for cellulosic fabrics.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

It has now been found that these objects can be attained by first treating the cellulosic fabric with a relatively dilute aqueous system and substantially immediately thereafter treating the cellulosic fabric with a formaldehyde solution of substantially lower water content.

,By pretreating the cellulosic fabric with water there is a swelling of the fabric to make it accessible for the subsequent reaction with the formaldehyde. As a result, the reaction with formaldehyde in the next step occurs more rapidly. The amount of water retained by the fabric in this step should be between 10 and 100% by weight of the fabric. In the second step the water present in the formaldehyde solution should not be over 50% and preferably not over 20%. The solution in the second step thus acts in the nature of a dehydrating agent in that it tends to extract the impregnated Water from the fabric while the formaldehyde diffuses into and reacts with the cellulosic material. The formaldehyde content of the solution is usually 5l0% but can be lower, e.g., 3%, or higher, e.g.,

While the first step of the treatment is instantaneous, the second step can vary from instantaneous up to 5 minutes, the time of treatment being inversely with the 3,371,983 Patented Mar. 5,1968

' ably 60-70%.

As a result of the two step treatment, there is obtained excellent wet crease recovery together with good tensile strength retention. At the same time the time of the formaldehyde reaction is greatly reduced over that normally employed in past operations for treating the cellulosic fabric with formaldehyde.

As the cellulosic fabric there can be employed cotton, linen, hemp, jute, ramie, sisal, rayons, e.g., regenerated cellulose (both viscose and cuprammonium, cellulose acetate, cellulose acetate-propionate, cellulose acetate-butyrate and ethyl cellulose and mixtures of such cellulosic fabrics with each other or other fabrics, e.g., nylon, acrylonitrile fibers or polyester fabrics. The invention is particularly applicable to the treatment of cotton fabric material such as cotton cloth.

There are two general methodsv for carrying out the above set forth two-step procedure.

In the first method the cellulosic fabric is padded to a 10100%, preferably 60-70%, weight pick up of an aqueous solution of a strong acid, or the salt of a weak base with a strong acid, e.g., phosphoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, trichloroacetic acid, formic acid, toluene sulfonic acid, ammonium chloride and ammonium sulfate. The acid strength can vary from moderate concentrations, e.g., 20% to as low as 0.01%, but preferably is between 0.5 and 6%. The preferred acid is hydrochloric acid, The acid treated fabric substantially immediately thereafter is treated with the formaldehyde solution in the dehydrating solvent, e.g., glacial acetic acid or 70% calcium chloride. A small amount of acid, e.g., 0.01-2%, can be added in the dehydrating solution if desired. Also, a portion of the formaldehyde can be added in the acid solution padded onto the fabric. However, a substantial portion of the formaldehyde, i.e., at least 50% should be added in the dehydrating solution. Since the initial padding with the acid solution is almost instantaneous and is usually carried out at room temperature, there is no significant reaction until the fabric is placed in the dehydrating solution.

In the second method the cellulosic fabric is padded to a 10-100%, preferably 60-70%, weight pick up of a solution of water containing a wetting agent, preferably 0.1- 1%. If the fabric is of the type which Wets out, the wetting agent can be omitted and plain water employed. While anionic and cationic wetting agents can be employed, the preferred wetting agents are nonionic in character.

Typical examples of nonionic wetting agents are alkylaryl polyether alcohols such as Triton 155, p-isooctylphenol condensed with 10 ethylene oxide units, Arlacel C (sorbitan sesquioleate), Brij 35 (polyethylene glycol lauryl ether), Ethofats (polyethylene esters of fatty acidsor rosin acids, e.g.- Ethofat 3, 7, ll, 13, 15 and 19), Ethomids, e.g., Ethomid 8, 10, 12 and 14, Igepal CA (alkylphenyl polyethylene glycol ether), Myrj (polyethylene glycol stearate), Ninol 1281 (fatty acid ethanolamide), Nonionic 218 (tertiary dodecyl polyethylene glycol thioether), Pluronics (condensation products of ethylene oxide and propylene oxide having molecular weights of 400 to 4000), Span 20 (sorbitan monolaurate), Span 40 (sorbitan monopalmitate), Span 60 (sorbitan monostcarate), Span 8O (sorbitan monooleate), Sterox CD (polyethylene glycol ester of tall oil acids), Triton X- (p-octylphenyl polyethylene glycol ether), Tween 20 3 (tris polyoxyethylene sorbitan monolaurate) and Tweens 40, 60 and 80 (the palmitates, stearates and oleates corresponding to the laurate of Tween 20).

There can also be employed anionic surface active agents such as alkyl and aryl sulfates and sulfonates, e.g., sodium alkyl benzene sulfonates having to 18 carbon atoms, sodium lauryl sulfate, Aerosol OT (sodium salt of dioctyl sulfosuccinate), sodium oleyl isethionate, sodium Nmethyl-N-oleyl laurate, sodium salt of propylated naphthalene sulfonic acid, sodium salt of sulfonated monoglyceride of cocoanut fatty acids, Areskap 100 (sodium salt of butylphenylphenol sulfonic acid), sodium lignin sulfonate, sodium dodecyl benzene sulfonate, sodium tetradecyl sulfate and sodium dihexyl sulfosuccinate. As cationic surface active agents there can be used lauryl trimethyl ammonium chloride, cetyl pyridinium chloride and octadecyl trimethyl ammonium chloride.

After the fabric is padded with the water, with or without the wetting agent, the wet fabric substantially immediately thereafter is impregnated with a dehydrating solution, e.g., anhydrous glacial acetic acid or an aqueous calcium chloride solution of concentration from 60% to saturation, e.g., 70%. The dehydrating solution con tains 5-10% of formaldehyde and also contains 0.01- of a strong acid, e.g., hydrochloric acid or sulfuric acid or any of the other acids previously set forth. The reaction time with formaldehyde is dependent upon the temperature in the same manner as in procedure 1.

Whether the first method or the second method i employed, it has been found that superior results are obtained by applying 248% of a crease-proofing resin. The crease-proofing resin can be applied before or after the formaldehyde treatment but is preferably applied first. The addition of the resin not only increases the dry wrinkle recovery angle but also increases the wet crease angle. Thus, reaction of formaldehyde aided the resin in increasing the dry wrinkle recovery angle while the resin correspondingly aided the formaldehyde in increasing the wet angle recovery. By using the resin treatment followed by the two step procedure of formaldehyde application of the present invention the decrease in tensile strength of the fabric can be limited to This is a much lower decrease in tensile strength than any of the previously employed formaldehyde or other reactive type treatments of cellulosic fabric for improving wrinkle resistance.

As the resin there can be employed any of the curable crease-proofing resins. These include the urea-aldehyde, e.g., urea-formaldehyde resin, dimethylolurea, dimethyl ether of urea-formaldehyde resin, aminotriazine-aldehyde resins, e.g., melamine-formaldehyde resins including alkylated melamine-formaldehyde, trimethylol melamine, methylated trimethylol melamine, tetrahydro-S-hydroxy- 2 (1H)-pyrimidone-formaldehyde resin, cyclic ethylene ura-formaldehyde, e.g., dimethylol ethylene urea, uronformaldehyde resins, e.g., dimethylol uron, Aerotex 23 (a triazine-formaldehyde resin believed to be a melamineformaldehyde type resin), Rohm and Haas Resin N-17 (a triazone-formaldehyde resin, e.g., dimethylol ethyl triazone), Dextraset 48 (a urea-formaldehyde resin), Eponite 100 (believed to be a butadiene diepoxide). Other polyepoxides can be used including bisphenol-A epichlorhydrin, 1,4-bis (2,3-epoxypropoxy) benzene, 1,3- bis (2,3-epoxypropoxy) octane, ethylene glycol diglycidyl ether, as well as any of the other polyepoxidcs set forth in Schroeder et al. Patent 2,774,691. Other crease-proofing agents such as those set forth in Textile Industries," October 1959, pp. 116-127, can also be used.

The time and temperature for curing the resins are those conveniently employed in the art. For convenience, cures at 350 F. (178 C.) for 1V2 minutes were employed in the specific examples.

Unless otherwise indicated, all parts and percentages are by weight.

In the drawings:

FIGURE 1 is a schematic diagram of a preferred'continuous operation according to the invention; and

FIGURE 2 is a schematic diagram of an alternative continuous operation.

Referring to FIGURE 1, the cotton cloth was passed substantially instantaneously through the resin padding tank 1 containing, for example, an aqueous solution :of melamine-formaldehyde. The cloth picked up 4% of resin. It then went to drier 2 where it remained for 1 /2 minutes at 300 F. (149 C.) and then to the curing oven 3 where it remained for 1 /2 minutes at 350 F. (178" C). The cotton cloth containing the cured resin next went substantially instantaneously through formaldehyde catalyst padding solution 4 which was 1.5% aqueous hydrochloric acid at room temperature. The cloth picked up approximately 60-70% of its own weight of the acid solution and then passed into formaldehyde reactor 5 maintained at C. The reactor contained 70% calcium chloride, 5% formaldehyde and 25% water. It took 30 seconds for the cloth to run through the reactor. The fabric was then treated in conventional fashion by passing through 10% aqueous ammonia for 30 seconds in neutralization chamher 6 and then washed in water for 30 seconds in washing operation 7. The cloth was then dried in drier 8 for several minutes at NO C. to remove the water.

Referring to FTGURE 2, the cotton cloth was passed substantially instantaneously through the formaldehyde catalyst padding solution 9 containing 2% aqueous hydrochloric acid at room temperature. The cloth picked Lp of its own weight of the acid solution and then passed into formaldehyde reactor 10 maintained at 50 C. The reactor contained 8% formaldehyde dissolved in anhydrous glacial acetic acid, It took about one minute for the cloth to run through the reactor. The fabric then passed through 10% aqueous ammonia for 30 seconds in neutralization chamber 11 and then was Washed with water for 30 seconds in washing operation 12 and dried for several minutes at 110 C. in drier 13. The dried formaldehyde treated fabric then passed substantially instantaneously through resin padding tank 14 containing, for example, an aqueous solution of methylated ureaformaldehyde. The cloth picked up 6% of resin. It then went to drier 15 where it remained for 1 /2 minutes at 300 F. (149 C.) and then to the curing oven 16 where it remained for 1 /2 minutes at 350 F. (178 C.). The cotton cloth was then washed in washing operation 17 to remove any remaining acid and again dried.

Table 1 shows the results obtained by treating cotton cloth with an aqueous solution of hydrochloric acid to a pick up of 6070% of the weight of the fabric followed by reaction with a glacial acetic acid solution containing 8% formaldehyde. No resin treatment was utilized. Examples 2-6 in the table are in accordance with the invention and Examples 1 and 7 are controls. Example 7 shows the properties of the cloth without any treatment.

TA B LE 1 Temperature Time Pad Solution Tensile Stren th, Wet Wrinkle Re Example C.) (m (60-70% Pickup) W & F (lbs. eovery, W & F

(Monsanto) 1.. 5 water 63 X 51 2.88 X 2.82 90 1 0.6% HCL- 37 X 25 3.65 X 3.62 70 1 1. 0% HC] 37 X 25 3. 58 X 3.5 70 1 0.5% HC 43 X 34 3.48 X 3.45 50 1 1.5% HCl 50 X 30 3.3 X 3.3 30 1 0.0% HCl 44 X 35 3. 44 X 3.4 l 61 X 51 3.0 X 2.90

Table 2 shows the results obtained by treating cotton productv had a tensile strength (lbs) 47 x 37 (W & F), cloth with a 1% aqueous solution of Triton 155 (higher dry wrinkle recovery W & F)' of 2.7 x 3.0 and a wet alkyl aryl monoether of polyethylene glycol) to a pick wrinkle recovery (W & F) of 3.52 x 3.52. 1 up of 60-70% of the weight of the fabric followed by reaction with a glacial acetic acid solution containing 8% formaldehyde and the indicated amounts of HCl. Ex- Cotton cloth was Padded Wlth 1% aqueous Hcl to 3 Example 31 amples 8-18 are in accordance with the invention. Ex- E was imfniidlately theriafler ample 19 is a comparison example wherein the cotton Pfegnated Wlth a Solutlon contammg 70% f cloth was in the dry state before entering the formalder1c 1e10% formaldehydefand-zoqa' water at fen /2 hyde reactor (i.e., there was no previous water pick up) minuteand Example 20 shows the properties of the cloth with- Example 32 out any treatment. Cotton: cloth was padded in a substantially instantane- TABLE 2 Temperature n il rength Wet Wrinkle Example C.) 1 Time (min) Percent HCl Filling (lbs.) Recovery, W dz F (Monsanto) 90 0. 5 l8 3. 72x3. 67 90 1 0. 5 3. 93x3. 93 70 1 0. 5 24 3. 73x3. 75 50 1 0.5 31 3.4 x3. 52 1 0.5 39 3.2 x3. 2 90 3 0.01 34 3.5 3.4 70 3 0.05 31 3.5 3.4 50 3 0.2 27 3.5 x 70- 0.4 27 3.5 x35 70 2. 0 23 3. 70x3. 74 30 5 2. 0 33 3. 63x3. 65 30 5 2. 0 32 2. 32x3. 09 2o 51 3. 05x2. 90

Table 3 shows the results obtained by padding cotton cloth with 6.0% aqueous hydrochloric acid to a pick up of 60-70% by weight of the cloth followed by impregnaous manner with 1.3% of aqueous-HCl at room tempertion with 8% formaldehyde in glacial acetic acid for 1-3 35 ature to a pick up of 60-70% by weight of the fabric. minutes at 30-35 C. followed by neutralization, washing The cloth then passed through a solution containing 60% and drying and then padding with an aqueous. solution calcium chloride, 5% formaldehyde, 1% HCl and 34% of Aerotex 23 resin to a pick up of 10% by weight of the water for 45' seconds at 50 C. The product had the cloth in Examples 21-24 and to a pick up of 8% in following properties:

Examples 26-29. Example 25 was a comparison example wherein the fabric was treated only with 10% of the Tensil strength (filler) lbs 33 resin (no formaldehyde treatment). In Examples 21-29 Dry wrinkle recovery (W& F) 3.1 x 2.8 after the resin padding operation, the cloth was dried Wet wrinkle recovery (W & F) 3.4 x 3.5 for 1 /2 minutes at 300 F. (149 C.) and then cured Formaldehyde pick up percent 0.354 for 1 /2 minutes at 350 F. (178 C.).

Table 4 shows the results obtained using the procedure TABLE 3 illustrated in FIGURE 1 with four different commercially Tensile Strength, Dry wrinkle Wet wrinkle available crease-proofing resins. The resins were padded X 2? a fig ig f f F z m sg g f F onto the cotton cloth in an amount of 8%, the cloth dried for 1 /2 minutes at 300 F. (149 C.) and then cured at 22:33 -g gi-g 2 2 350 F. (178 C.) for 1 /2 minutes. The cloth was then 45x25 5,; j x3153 padded with 1.5% aqueous HCl followed immediately g3 g2 33 i g: g; i 33 by impregnation with a mixture of 70% calcium chloride, 46x29 5 1. 1 1 5% formaldehyde, 0.2% HCl and the balance water at 2333?. 3133131 53 313333 5 8 55 1 mute- 40x27 3.511430 3.58x3.61

TABLE 4 Tensile Dry Wrinkle Wet Wrinkle Strength Recovery, W dz F Recovery, W &F Example Resin (Filling) lbs.

33 Aerotex 23 32 3 1 x 3.08 3. 67x 3.58 Rhonite N-17 34 3 0 x 3. 0 3.38 x 3. 4s Dextraset 4s 35 3 is x 3.09 3.45 x 3. 4s 3s Eponlte 100 37 2 82 x 2.85 3.33 x 3. 32

Example 30 In the present specification and claims when the percent of calcium chloride is referred to it is calculated as Using the procedure shown in FIGURE 1, there was calcium chloride hexahydrate which is the commercially padded onto cotton cloth 4% of Aerotex 23. The resin available form.

was cured for 1 /2 minutes at 350 F. (178 C.). There We claim:

was then padded on the cloth a 1% aqueous HCl solu- 1. A continuous process for increasing the wet wrinkle tion to a pick up of 60-70% by weight of the cloth recovery of a cellulosic fabric comprising treating the followed by impregnation with 8% formaldehyde in fabric with an aqueous medium in which water is the sole glacial acetic acid for 2 minutes at 50 C. There was a essential liquid until the fabric contains 10-100% of its pick up of 0.670% formaldehyde on the fabric. The own weight of added water, substantially immediately 7 thereafter passing the wet fabric into a dehydrating solution of formaldehyde at a temperature up to 90 C. for a period of up to 5 minutes whereby the formaldehyde reacts with said fabric to improve the wet wrinkle recovery, Washing the thus treated fabric with water and then drying said fabric.

2. A process according to claim 1 in which the fabric is a cotton fabric.

3. A process according to claim 1 wherein the dehydrating solution is one selected from the group consisting of (a) an aqueous solution containing at least 50% calcium chloride, calculated as calcium chloride hexahydrate, and at least 3% formaldehyde; and (b) anhydrous acetic acid containing at least 3% formaldehyde.

4. A process according to claim 3 wherein the treatment with formaldehyde is carried out in the presence of an acid catalyst and the fabric, directly after the formaldehyde treatment, is passed through an acid-neutralizing bath and then washed and dried.

5. A process according to claim 4 wherein the acid catalyst is present in the aqueous medium and said medium includes not more than 50% of the formaldehyde requirements for said process.

6. A process according to claim 4 wherein the acid catalyst is in the dehydrating solution and the aqueous medium includes a fabric wetting agent.

7. A process according to claim 4 including the application of a crease-proofing resin to said fabric prior to the formaldehyde treatment.

8. A process according to claim 4 including the application of a crease-proofing resin to said fabric after the formaldehyde treatment.

9. The process of claim 4 wherein said acid catalyst is hydrochloric acid, and the dehydrating solution is an aqueous solution of calcium chloride at a temperature of 5090 C.

10. The process of claim 9 wherein the treatment with said dehydrating solution takes from 30 seconds to 1 minute,

11. The process of claim 10 wherein the cloth is kept in open width throughout.

References Cited UNITED STATES PATENTS 2,080,043 5/1937 Heckert 8-116.3

995,852 6/1911 Eschalier 8-116.4 2,338,983 1/1944 Thackston 8-116.3 2,593,207 4/1952 Silver 8-116.3 3,046,079 7/ 1962 Reeves 8116.4 2,689,194 9/1954 Russell 8-116.4 X 2,922,768 1/ 1960 Mino et a1. 2,243,765 5/1941 Morton 8116.4 3,189,404 6/1965 Takizaki et al. 8-1164 3,175,875 5/1965 Gagarine 8116.4 X 3,265,463 8/1966 Barber et al. 8116.4 X 3,038,777 6/1962 Daul et al. 8116.4

FOREIGN PATENTS 462,005 3/ 1937 Great Britain, 568,258 3/1945 Great Britain.

Datye et al., Textile Research Journal, vol. 30, 72-73 January 1960.

Reeves et al., Textile Research Journal vol. 30, 179-192 March 1960.

Daul et al., Textile Research Journal, vol. 23, 738-747 August 1954.

J. TRAVIS BROWN, Acting Primary Examiner.

A. LOUIS MONACELL, J. S. LEVITT, J. T. BROWN,

Examiners. J. CANNON, Assistant Examiner.

Claims (1)

1. A CONTINUOUS PROCESS FOR INCREASING THE WET WRINKLE RECOVERY OF A CELLULOSIC FABRIC COMPRISING TREATING THE FABRIC WITH AN AQUEOUS MEDIUM IN WHICH WATER IS THE SOLE ESSENTIAL LIQUID UNTIL THE FABRIC CONTAINS 10-100% OF ITS OWN WEIGHT OF ADDED WATER, SUBSTANTIALLY IMMEDIATELY THEREAFTER PASSING THE WET FABRIC INTO A DEHYDRATING SOLUTION OF FORMALDEHYDE AT A TEMPERATURE UP TO 90*C. FOR A PERIOD OF UP TO 5 MINUTES WHEREBY THE FORMALDEHYDE REACTS WITH SAID FABRIC TO IMPROVE THE WET WRINKLE RECOVERY, WASHING THE THUS TREATED FABRIC WITH WATER AND THEN DRYING SAID FABRIC.

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