IL23476A

IL23476A - Aldehyde fixation on polymeric material

Info

Publication number: IL23476A
Application number: IL23476A
Authority: IL
Original assignee: West Point Pepperell Inc
Priority date: 1964-06-02
Filing date: 1965-05-04
Publication date: 1969-03-27
Also published as: ES313722A1; SE325861B; GB1118742A; AT274729B; FR1440959A; DE1469507A1; CH727065A4; LU48722A1; AT268189B; NL143638B; OA01738A; GB1118741A; NL6506839A; NO123814B; CH557447A; FI43864B; DK120632B; US3420696A

Description

C O H E N Z E D E & S P I S B A C H RE GD. PAT E NT ATTORN EYS 24, LEVONTIN STR., P. O. B. 1169 P A T E N T S & D E S I G N S O R D I N A N C E 13187/65· SPECIFICATION A LDEHYDE FIXATION ON POLYMERIC MA TERIA L We , WEST PQINT-PEPPERE LL, INC. , a corporation of Georgia, of West Point, Georgia, U.S.A., DO HEREBY DECLARE the nature of this invention and in what manner the same is to be performed to be particularly described and ascertained in and by the following statement: This invention relates to a novel and improved process for the fixation of an aldehyde on cellulose, cellulose esters and starch. It is known to fix aldehydes such as formaldehyde for example, on cellulose, cellulose eeters and starch. In such prior art processes, however, it has been found difficult to predetermine the amount of formaldehyde fixed, and to reproducibly control the amount of formaldehyde fixed. Also, in some instances, there is required the use of concentrated solutions of formaldehyde with high amounts of acid that tend to degrade the material being treated. Additionally, in such prior art processes, the efficiency is low in the sense that only a small amount of the formaldehyde used is actually bound on the substrate, such as cellulose, the remainder being lost. The Invention relates also to a novel aqueous formaldehyde composition.

It has previously been proposed to apply a precondensate of formaldehyde with an alkyl carbamate, e.g. formaldehyde-methyl carbamate pro ondensate, to cellulose. In such procedure, there is a fixation of the nitrogen of the precondensate to the cellulose molecule, as can be verified by the significant increase in nitrogen content of the treated cellulose over the relatively minor amount of nitrogen present in the untreated cellulose material.

It is a principal object of the present invention to durably fix an aldehyde, preferably formaldehyde, to cellulose, cellulose esters and starch. Yet another object is to provide an aldehyde fixation process in which the degree of aldehyde fixation is readily and precisely controllable and reproducible. The process is exceedingly efficient, economical and rapid. The aldehyde is permanently fixed, proof against repeated washing.

Another object is to Impart wash-and-wear properties and crease resistance to cellulose fabrics. A related object is to stabilize cellulose fabrics against shrinkage. The process is particularly advantageous in that it involves substantially less loss of strength than does conventional resin finishing, while achieving a high level of wash-wear performance.

Yet another object is to provide wash-wear fabrics cross linked with formaldehyde, which do not retain chlorine or Other-wise discolor or pick up soil in the course of repeated washings. Related objects are to provide celiulosic fabrics which are mildew-proof and rot resistant.

An additional object is to Improve the permanent crease retention properties of cellulosic fabrics.

Another object is to increase the wet strength properties of paper.

Another object is to provide a novel formaldehyde composition, suitable for fixing and other purposes.

A still further object is to reduce the swilling tendency of cellulosic fabrics when wet with water or aqueous solutions, and especially of nonwoven viscose rayon fabrics.

Yet another object is to achieve better whiteness retention. Further objects will be in part evident and in part pointed hereinafter.

In accordance with the present invention, the foregoing objects can be attained by treating starch, cellulose or a cellulose ester with an aqueous mixture containing one of the following materials: (1) a mixture of an aldehyde and an alkyl carbamate, (2) an aldehyde-alkyl carbamate condensation product, (3) a mix-ture of an aldehyde together with an aldehyde-alkyl carbamate condensation product. In place of the alkyl carbamate in (1), (2) or (3) there can be used an aryl carbamate . There also can be used N-hydrocarbyl substituted alkyl or aryl carbamates. After the material is treated with the aqueous mixture, it is heated to a temperature sufficient to fix the aldehyde on the cellulose or the like, but insufficient to cause any substantial nitrogen fixation on the material treated. The cellulose can be in the form of cotton, alpha cellulose, regenerated cellulose or rayon, e.g. cuprammonium rayon or viscose rayon, or paper. As cellulose esters, there can be employed cellulose acetate, cellulose acetate-butyrate, and cellulose acetate-propionate . As the aldehyde, there can be employed formaldehyde, glyoxal, pyruvic aldehyde, glutaraldehyde, acetaldehyde, proplonaldehyde, butyraldehyde and hydroxyadipaldehyde . The preferred aldehyde is formaldehyde.

The cellulose material can be blended with synthetic fibers such as polyesters, e.g. polyethylene te ephthalate , acrylic fibers, e.g. polyacrylonitrile , acrylonitrile-vinyl chloride (85.15 or 15:85), nylon, e.g. polymeric hexamethylene adipamide, polypropylene, propylene ethylene copolymers, spandex, vinyl-chloride vinyl acetate, e.g. (87:13).

For special purposes where extra rigidity is required, it is desirable to employ glyoxal. When less rigidity than that imparted by formaldehyde is desired, other aldehydes such as acetaldehyde or hydroxyadipaldehyde can be used. Of course, mixtures of aldehydes can be employed.

The alkyl carbamate has the formula: HgNCOOR where R is an alkyl group. Thus, there can be employed methyl carbamate, ethyl carbamate, propyl carbamate, isopropyl carbamate, butyl carbamate, amyl carbamate , hexyl carbamate, octyl carbamate, decyl carbamate, dodecyl carbamate, cyclohexyl carbamate and octa-decyl carbamate. Mixtures of carbamates can be employed, e.g. the eutectic mixture of ethyl carbamate and 856 methyl carbamate.

As aryl carbamates, there can be employed phenyl carbamate, o-tolyl carbamate, p-tolyl carbamate, m-tolyl carbamate, p-butyl-phenyl carbamate, a-naphthyl carbamate, β-naphthyl carbamate, 2, 4-xylyl carbamate.

As N-hydrocarbyl substituted carbamates having the formula RjNHCOORg where Rj and R2 are alkyl or aryl, there can be used N-phenyl Isopropyl carbamate, N-phenyl phenyl carbamate, N-p-tolyl ethyl carbamate, N-phenyl methyl carbamate, N-phenyl ethyl carbamate, -methyl phenyl carbamate, N-ethyl phenyl carbamate, N-methyl methyl carbamate, N-methyl ethyl carbamate, N-methyl decyl carbamate, N-ethyl methyl carbamate, N-ethyl ethyl carbamate, N-dodecyl methyl carbamate, N-butyl cyelohexyl carbamate, N*N-dlethyl ethyl carbamate, N,N-dlmethyl ethyl carbamate, Ν,Ν-dlethyl methyl carbamate, Ν,Ν-dlphenyl methyl carbamate.

Higher temperatures are generally required to activate the aryl carbamates and the N-hydrocarbyl carbamates than is the case with the lower alkyl carbamates such as methyl carbamate and ethyl carbamate. Hence, these latter compounds are usually preferred.

As indicated, there can also be employed an aldehyde-alkyl carbamate condensation product (or an N-hydrocarbyl carbamate or an aryl carbamate ) . Preferably, however, there is employed a mixture of the aldehyde and alkyl carbamate, since it has been found that the reaction proceeds more smoothly, and shorter process times are normally required. Additionally, the use of the mixture eliminates the expense of preforming the aldehyde-alkyl carbamate condensation product.

When utilizing an aldehyde-alkyl carbamate condensation product, it is important that the heating of the treated product be at a temperature not above about 300°P, because if a higher temperature, such as 350eP, is utilized, instead of the condensa-tion product decomposing to form ammonia, carbon dioxide and an alcohol, the competing reaction of nitrogen fixation to cellulose through the methylol group tends to take place in accordance with prior art procedures.

On the other hand, when utilizing an aqueous mixture of an aldehyde and a carbamate , the temperature of heating the product in order to fix the formaldehyde to cellulose or the like can be varied much more widely. Thus, not only can temperatures of l80 to 300 °P be employed, but there can be utilized more elevated temperatures, such as 350 or 400 eF .

Unless otherwise specified, throughout the specification and claims, the temperature of heating the product connotes the actual temperature to which the product is elevated, as determined for example by surface pyrometry or infrared pyrometry in the case of moving fabrics; as will be understood, this will normally correspond to a somewhat higher oven temperature , or the desired temperature level may be achieved by radiation from heat sources tbem-selves at a considerably higher temperature . The apparent reason for this is that the reaction to form the methylol carbamate proceeds relatively slowly, whereas the reaction to fix the formaldehyde to cellulose or the like goes quite rapidly, product temperatures of 180-300°F are preferred, as less likely to degrade the product . A preferred cure or fixation temperature range for cotton is 200-220°F .

Surprisingly, it has been found that the carbamate acts only as a carrier in assisting the formaldehyde to become fixed on the cellulose or the like , but does not itself become fixed In any significant amount to the cellulose material being treated.

It has been observed that in order to aid in fixing formaldehyde or other aldehyde on cellulose or the like , there should be employed at least O .ljG, and more preferably at least 0.¾i by weight of methyl carbamate , for example , in the aqueous solution or dispersion, or equivalent molar percentage by weight of other carbamate used. It is difficult to maintain control of the amount of formaldehyde fixed to the cellulose if less than 0.1$ of methyl carbamate or equivalent is in the solution or dispersion . For more control of the reproducibility of formaldehyde fixation, It is desirable to use at least 0.¾£ of methyl carbamate or equivalent in the aqueous system. Throughout the present specification and claims, unless otherwise Indicated, all parts and percentages Higher amounts of carbamate, e.g., 1$ to 5$ or more by weight of methyl carbamate (or other carbamate) In water, can be employed, but normally there Is no advantage In utilizing excess amounts since they do not appear to give better results than does 1$ or so, which would justify the increased cost of the reagent. Preferably, the alkyl carbamate employed is a lower alkyl carbamate; most preferably methyl carbamate, ethyl carbamate and mixtures thereof.

The aldehyde Is employed in the aqueous system in an amount normally between 1$ and 8$ thereof, although if relatively larger amounts of formaldehyde are to be fixed onto the cellulose or other material, there can be used as much as 10$ or 15$ or more of aldehyde. Desirably, the aldehyde is employed in an amount of at least 3 moles per mole of carbamate, and can be employed in an amount as much as 60 moles or even 100 moles per mole of carbamate. Generally, lower mole proportions of aldehyde are preferred, and one of the advantages of the present invention is that lower amounts of aldehyde re required in the aqueous treating system, for the amount of formaldehyde fixed on the cellulosle material, than is the case with prior art processes. Additionally, the problem of formaldehyde odor is thereby materially reduced.

When treating cotton, alpha cellulose, starch and paper, there is usually employed an aqueous solution containing 1.25-4.0$ of formaldehyde, in order to fix 0.25-1.25$ formaldehyde, onto the treated material.

When treating rayon and cellulose esters, there is usually employed an aqueous solution containing 2.5-3.0$ of formaldehyde, in order to fix 0.50-2.5$ formaldehyde, onto the treated material. Of oourse, with any of the materials there can be employed a solu-tion containing 1.25-8.0$ of formaldehyde, to fix 0.25-2.5$ formaldehyde, by weight of the treated material.

When employing a carbamate -aldehyde condensation product, there is preferably added to the solution enough aldehyde to bring the aldehyde level to at least 3 molee of aldehyde (including that in the condensation product) per mole of carbamate present in the condensate .

The mixture of aldehyde and alkyl carbamate, e.g. formaldehyde and methyl carbamate , can be shipped as an aqueous mixture containing the two materials in any of the proportions indicated above . This aqueous mixture can be relatively concentrated at the time of shipment and can then be diluted with water to obtain the desired amount of ingredients for the bath through which is passed the cotton, for e am le. For stability purposes, the mixture which is shipped is preferably neutral, although it can be alkaline or acidic .

The bath through which the cotton or other material is passed is generally acidic or has a latent acid catalyst therein. Suitable acids and latent acid catalysts include formic acid, hydrochloric acid, ammonium chlotide. magnesium chloride, ealcium chloride, zinc nitrate, zinc chloride, zinc fluoroborate , or raix-tures thereof. Since little catalyst is required, it may be supplied by residual acid-forming salt, auch as ammonium chloride, on the goods being treated.

Fixation of an aldehyde on the material, utilizing the alkyl carbamate carrier has also been found to be operative on the alkaline side, e.g. using catalysts such as sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide or potassium hydroxide. For most purposes, acid catalysts are preferred. As in the former case, the alkaline catalyst may be supplied on the goods being treated. When catalyst is added to the treating bath, it is normally used in an amount of 0.1-2# of the bath, although this can be varied.

The normal procedure for applying the aldehyde and carbamate mixture to the material is to pass a fabric, fibers, sheet or continuous yarn through the aqueous mixture of aldehyde and carbamate, and then to run the thus impregnated material through squeeze rolls to remove excess solution. In the case of yarn, the procedure may be to pass the solution through packages of the yarn in a kier. A similar process can be employed in treating starch.

The process of the present invention has the advantage over prior art processes of fixing aldehyde to material such as those described above, with good reproducibility of results, particularly when the alkyl carbamate is present in the treating mixture in an amount of at least about 0.5$. A further advantage is that any desired amount of aldehyde can be fixed to the cellulose or the like, simply by controlling the amount of aldehyde in the aqueous mixture .

Of course, there can be added to the aqueous mixture of aldehyde and alkyl carbamate (or aldehyde-alkyl carbamate condensation product), conventional additives, such as wetting agents, hand modifiers, softeners, lubricants, brighteners, and the like.

While formaldehyde is preferably employed as such in the aqueous mixture, it Is possible to utilize sources df formaldehyde such as paraformaldehyde, trloxane, and hexamethylenetetramine . In the case of such materials, however, there is a slight lengthening of the overall time of the process in order to permit the breakdown of these materials to monomerlc formaldehyde. For maximum efficiency, it has been found that a mole ratio of formaldehyde to alkyl carbamate of about 12.5:1 gives best results. The present process is simpler to operate than the prior art procedures, and furthermore has the advantage that it is unnecessary to employ therein concentrated acid solutions or the like which are not only difficult to work with, but furthermore degrade the material.

An outstanding advantage of the process resides in the circumstance that formaldehyde may be fixed on the base material, for example on cotton yarn or fabric, with considerable reduction in loss of strength as compared with conventional resin finishing processes. In the latter loss of 40 to 50# of original strength is common, and may exceed 50 . This sizable loss in strength is commonly compensateid for by providing extra strength (and material) in the greige goods, at added cost. In the present process, the loss of strength is commonly only 15-25# and rarely over 30#. It is believed that this favorable result is due primarily to three circumstances — the low temperature of drying that is required to fix the aldehyde, as compared to the high temperatures of normal resin curing conditions, the low concentration of catalyst used, and the fact that drying need not be carried to the end point of zero moisture content. Excellent results have been obtained with drying to a residual moisture content of 2- # measured with a resistance type moisture measuring device. For very best results the fabric is carried to the point of substantially being bone dry. The process of the present invention also imparts better whiteness retention to cellulose fabrics, e.g. viscose rayon fabrics, cotton fabrics and fabrics containing blends of synthetic and cellulosic fibers.

The present invention is also important in greatly reducing the swelling properties of cellulosic fabrics.

This is particularly true in the case of viscose rayon, especially nonwoven viscose rayon fabrics. Consequently the aldehyde and carbamate treatment of the present invention not only gives a cellulosic product, e.g. viscose rayon, of reduced swelling properties, but concomitant therewith yields Improved stabilization against shrinkage .

EXAMPLE I Generally, the border yarns In towels shrink more than the rest of the towel. In order to overcome this defect, a series of towel border cotton yarns were treated in a kler with an aqueous mixture containing 1% methyl carbamate, 0.5 magnesium chloride hexahydrate, 0.5# formic acid, 1.2# sodium chloride, 0.17# of a dimethyl polysiloxane oil (softener), and the amounts of formaldehyde indicated below. After the treatment with the aqueous solution, the yarns were dried at 200° P. The treated yarns were then woven into the borders of cotton towels with the results indicated in the following table: TABUS I Formaldehyde Nitrogen Yarn in Yarn In Molar Ratio Yarn in Towel ¾rn In Towel Border* Formaldehyde : Finished Laundered Finished Laundered Pull-In In Sample Methyl Carbamate Towel JgO Times Towel 30 Times 30 Launders 1 2.5:1 ** 0.14 0.13 0.03 0.05 3.1# 2 5.0:1 Ο.28 0.30 O.05 0.05 -0.2 3 7.5:1 Ο.56 Ο.56 O.07 0.07 -0.8 4 10.0:1 0.77 0.72 0.08 0.04 -1.9 12.5:1 1.13 0.95 O.07 0.07 -1.2 6 2.5:1 0.16 0*16 0.04 O.03 1.6 7 Untreated Control — — O.O3 0.07 6.3 (Treated Yarn Average) Ο.Ο58 Ο.Ο52 ♦Border pull-in « Width of Towel Body - Width of Towel Border Width of Towel Body xlOO (i.e., Differential Shrinkage) **A preoondensate of methyl carbamate and formaldehyde was employed If the methyl carbamate had been affixed to the yam, the amount of nitrogen would have been at least Ο.2656 for the sample having I.I356 of formaldehyde in the yarn (Sample 5).

The strength retention of the yarns treated in this example was very good. It is significant that strength retention was not dependent upon the level of formaldehyde fixed in the yarn. The strength retention is indicated in the following table.

TABLE 2 Skein Single End Sample Breaking Strength Retention Break Retention 1 31 lb. 76 5.20 lb. 69 2 298 72 5.32 71 3 306 74 5.33 71 4 316 77 5.37 72 316 77 5.63 75 6 263 64 5.07 68 7-Control 411 — 7.48 The streng-cn retentions appearing above were based on bleached, mercerized yarn taken immediately before treatment with methyl carbamate and formaldehyde. When the strength retention calculation is based on the greige, mercerized yarn (6.37 lb. single end break), the state at which yarn strength is normally determined, strength retention of the above yarns is from 80 to 88 per cent.

EXAMPLE II Cotton yarn in a kier was saturated with an aqueous mixture containing 0. $ magnesium chloride hexahydrate, 0.5 formic acid, Ο.356 methyl carbamate and the indicated amounts of formaldehyde. The yarns were then vacuum extracted and dried at l80eP to 2-356 residual moisture. 2 1.5 0.40 12.5:1 3 2.5 0.52 20.8:1 4 2.7 Ο.52 22.5:1 The amount of fixed formaldehyde on the yarn is usually about 20 to 25# of the formaldehyde content of the aqueous mixture EXAMPLE III An aqueous mixture containing 5# formaldehyde, 1# methyl carbamate and 1# magnesium chloride hexahydrate was padded on a bleached enameling duck at 55 - 60 wet pick p. The fabric was barely dried at l80eP (about 10 moisture), and heated at the indi cated temperatures and times.

TABLE 4 (2) Appearance Warp (l) Time Formaldehyde % Nitrogen Rating (1) Shrinkage Minutes Fixed on Fabric on Fabric 5L 20L 3L 20L 220 5 0.52 0.07 4.0 3.5 4.3* 4.1<£ 260 3 0.47 0.08 3.0 4.0 2.8 2.5 300 2 0.50 0.08 3.5 4.0 2.4 2.1 1 0.57 0.09 4.0 4.0 1.9 2.0 300 15 0.58 0.09 3-5 3.0 3-3 3.5 Control — 0.04 -__ 8.3 — - (1) Determined on fabric laundered five and twenty times in an automatic washer with a rated capacity of 8 lbs. Fabric load was 8 lbs; wash temperature was 105eF; fabric was tumbled dried in an automatic clothes dryer. Rated on AATCC 5 (best) to 1 (poor) scale. (2) Fabric scoured one hour at 200eF. in 0.25# chip soap and 0.50$ soda ash, followed by thorough rinsing.

EXAMPLE IV In another set of samples using a mercerized and bleached 19 136 x 64 cotton broadcloth, an aqueous solution containing 2.5$ formaldehyde, 1.0 methyl carbamate and catalyst as noted was applied at 60# wet pickup. The fabric was barely dried at l80°F (about IO56 moisture) and heated at 260°F for 3 minutes.

ABLE 5 Nitrogen Crease Recovery <& Formaldehyde (1) Before After Angles (W+P) Sample Catalyst System Fixed Scour Scour Dry Wet 1 0.72 0.08 0.07 252" 212° 2 1# MgCl2.6H20 0.70 0.05 0.08 259° 246° 3 1# HCOOH 0.70 0.02 0.02 2 5* 234° 4 0.1# NH^Cl ^ 0.70 0.08 0.10 257e 242e Control 0.02 0.04 127° 159° (1) Fabric scoured one hour at 200°F. in 0.25 chip soap and 0.50£ soda ash followed by thorough rinsing.

Estimated. Bath was neutral - NHCI residual from preceding treatment of fabric.

Again only traces of nitrogen were found in the treated fabric, but it is important to note that the carbamate is not present on the fabric immediately after heating. This may be a clue in the determination of the mechanism of the reaction, because the carbamate is evidently decomposed by heating. A number of other samples have confirmed this observation.

EXAMPLE V Bleached, mercerized cotton yarn was treated in a kier with an aqueous solution containing 2.5 formaldehyde, I.3696 sodium chloride, 0.5# magnesium chloride hexahydrate, 0.5# formic acid, 0.1$ dimethyl polyslloxane oil and the indicated amounts of methyl carbamate, and later dried at l80°F.

TABLE 6 Mole Ratio Formaldehyde # Methyl Formaldehyde Sample to Methyl Carbamate Carbamate Fixed 1 62.5:1 0.1 0.30 2 20.8:1 0.3 0.52 3 8.9:1 0.7 Ο.76 6.25:1 1.0 0.20 12.5:1 0.5 Ο.33 EXAMPLE VI A bleached, mercerized cotton yarn in a kier was treated with an aqueous solution containing 1.30 sodium chloride , 0.50 magnesium chloride hexahydrate , 0.50 formic acid, 0.10 dimethyl polysiloxane , 0.30 methyl carbamate and the indicated amounts of ormaldehyde . The treated yam was dried at l80eP .

TABLE 7 Mole Ratio Formalde- 0 Formaldehyde ø Formaldehyde Sample hyde to Carbamate in Solution Fixed 1 2.5 :1 O .J 0.05 2 7.5 :1 0.9 0.24 4 17.5 :1 2.1 0.34 22.5 : 1 2.7 0.52 EXAMPLE VII Mercerized cotton yarn was treated in a kier with an aqueous solution of the indicated amounts of materials and dried at 200eF . The methyl carbamate -formaldehyde precondensate was the condensation product of 2.5 moles of formaldehyde with 1 of methyl carbamate and is indicated in the table by MC-F . There was also present in tne aqueous solution 0.50 of polyethylene softener and 0.10 an alkylphenol -ethylene oxide condensate as a wetting agent .

TABLE 8 Sample Material 1 2 — 4 MC-F 40 80 40 40 MgCl2.H20 10 10 1.50 Zn (BP ) 2 — -- 1* H GOOH 10 10 1.50 10 0 CH20 fixed 0.630 1. 3 1.020 0.780 No fixed nitrogen was observed in the yarn .

EXA PEE VIII Both bleached, mercerized yarn and carded bleached cotton yarn were treated in a kier with an aqueous solution containing 2j6 of a methyl carbamate -formaldehyde precondeneate (mole ration 1 : 2.5) , 2.1$ free formaldehyde , 0. $ magnesium chloride, 0.5J6 formic acid, 2.5$ sodium chloride , 0.2$ sulfonated tallow (softener) and 0.025/6 of dimethyl polysiloxane . The yarns were dried at 200eP . The mercerized yam picked up 0.72$ fixed formaldehyde and the carded yarn 0.70$ fixed formaldehyde .

EXAMPLE IX Mercerized cotton yarn was treated in a kier with an aqueous solution of 0.5# ethyl carbamate , 2.1$ formaldehyde (mole ratio formaldehyde to carbamate of 12.5 : 1) » 0.5 magnesium chloride and 0. $ formic acid. The yarn was dried at 200°P to fix the formaldehyde to the yarn .

The ability of the carbamate -formaldehyde proce ss of the present invention to reduce swelling of fabrics is shown in the following examples in the treatment of needle punched nonwoven rayon fabrics .

Thus, a fabric which consists of an 8 oz . viscose rayon nonwoven web (Avril) needled into a 1.6 oz . polypropylene scrim, calendered and palmered had an objectionable tendency to swell and increase in gauge during wet processing . This objection can be overcome in part by using a combination of polypropylene fiber and viscose rayon for the web . Because of the thermoplasticity of the polypropylene , this combination of fibers in the web can be hot calendered and palmered to reduce the gauge of the base fabric and to reduce swe lling and gauge increase during predipping.

However, this fabric still swe lled and increased in gauge on wet-ting . Furthermore , the inclusion of the polypropylene fibers was a relatively expensive solution to the problem .

- - EXAMPLE X The fabrics employed were as follows : (a) 8 oz . viscose rayon (Avril) web needle punched into a 1.6 oz . polypropylene scrim fabric , (b) 8 oz . 60# polypropylene 40 8 oz . viscose rayon (Avril) web needle punched into a 1.6 oz . polypropylene scrim fabric (c) J.3 oz . 60# polypropylene 0$ viscose rayon (Avril) web needled into a 1.0 oz . cotton scrim fabric .

Fabrics (a) , (b) and (c) were all needled, calendered and palmered.

The aqueous mixture applied to the fabrics contained: methyl carbamate 1 formaldehyde 4$ magnesium chloride 0.8¾6 formic acid 0.83# nonylphenol -ethylene oxide adduct (wetting agent) 0.2$ Thi3 mixture is called Formulation A hereinafter.

Formulation A was applied at 120°F in a laboratory padder. Fabrics (a) and (b) were dried in a continuous oven at 250eF and fabric (c ) was dried in the oven at 220οΡ , the fabrics were rolled up and held in a convection oven at 220eF for 1 1/2 hours to simulate conditions obtained if the fabric should be wound up hot in commercial production . Thermocouples embedded in the fabric rolls indicated the temperature on the inside of the fabric roll to be When placed in the oven 125°F After 25 minutes 170°F After 4 minutes l85eF After 1 hour and 30 minutes 200 °F The gauges of these fabrics, before and after treatment, were measured with a Starrett Model 1010 spring loaded hand micrometer with a 1/4 inch anvil and 1/4 inch foot . The gauge was also measured after wetting in water.

Fixed Gauge Gauge Formaldehyde (Dry) (Saturated in Water) Fabric (a) not treated 0 40 mils 68 mils Fabric (a) treated 0.66# 45 " 59 " Fabric (b) not treated 0 40 " 41 " Fabric (b) treated 0. 1$ 34 " 36 " Fabric (c) not treated 0 22 '* 29 " Fabric (c) treated Ο.5656 23 " 25 " The treated sample in each pair had an appreciably lower wet gauge than did the fabric not treated. The treatment also caused further compression and restriction of fabric (b), a fabric which as constructed was devised to restrict swelling. The formaldehyde fixation in this and the following examples is based on the total weight of the fabric.

EXAMPLE XI The fabric employed was 8 oz. viscose rayon web needled into a 1.6 oz. polypropylene scrim, calendered and palmered.

Formulation A (see Example X) was applied to one section of the fabric on a laboratory padder. One portion of this section was vacuum extracted between the top roll of the padder and the fabric wind-up. A second portion of this section was not vacuum extracted. Another section of the fabric was untreated. The fabrics were dried continuously in a laboratory oven at 250°F. A radiation pyrometer (Infrascope) indicated the fabric temperature at the exit to be 221°F for the fabric vacuum extracted and 2l8°F on the fabric not vacuum extracted.

The results of swelling tests on these fabrics were as follows .· Gauge Gauge Fixed Gauge Saturated Saturated Formaldehyde (dry) With Water 10# NaOH Not Treated 0 39 mils 50 mils 70 mils Treated 0.51 8 " 47 " Vacuum Extracted- 0.68$ 9 " 48 »» 60 mils Treated The apparent slight decrease in gauge of the two treated fabrics is illusory since the results are the averages of ten readings and the variation is about +2 mils.

EXAMPLE XII The fabric3 employed were as follows: (a) 8 oz. viscose rayon web needle punched into a 1.6 oz. polypropylene scrim fabric, calendered and palmered, (b) 8 oz. 60 viscose rayon polypropylene web needled into a 1.6 oz. polypropylene scrim, (c) 8 oz. 6Ο56 viscose rayon polypropylene web needled into a 1.6 oz. polypropylene scrim, calendered and palmered.

The treating solutions were: Formulation A (See Example X) Formulation B (the same as Formulation A, except it contained 8# of formaldehyde) Formulation C (the same as Formulation A, except it contained 2# methyl carbamate and 856 formaldehyde).

The formulations were all applied at room temperature in a laboratory padder and vacuum extracted.

The fabrics were dried in a laboratory continuous dryer set at 260*F. The fabric treated with Formulation A attained a surface temperature of 232eF., the fabric treated with Formulation B attained a surface temperature of 2l °F, and the fabric treated with Formulation C attained a surface temperature of 210°F. These differences in temperature had an influence on the level of for-maldehyde fixed in the fabric. after drying, these fabrics were treated with sodium bisulfite solution to remove formaldehyde odor and recatalyzed with an aqueous mixture containing 0.8¾6 each of gCl^ and formic acid. The fabrics were then dried to the touch in a 300°F oven after the washing and recatalyzation.

The fabrics were hot calenSered on a two-roll calender at 250eF and then palmered two passes at 260eF on one drum of a two-drum compressive shrinkage machine .

The swelling effect was determined as in Examples X and XI by gauging the fabric dry, saturated with water and saturated with NaOH solution . Swelling characteristics were checked as finished in the laboratory (before calendering) , after calendering and after calendering and palmering. The results of these tests and of formaldehyde analyses are set forth in the following table : % Fixed Gauge Gauge Gauge Fabric Formulation CH 0 (Dry) Saturated With Saturated 2 Water With 2$ NaOH (a) Not treated 0 42 mils 4 mils 70 mils (a) A Before calendered 0.72 47 48 58 (a) A Calendered — 36 47 54 (a) A Calendered 0.77 36 45 54 and palmered (a) B Before Calendered 0.60 45 47 58 (a) B Calendered — 36 47 53 (a) B Calendered 0.47 32 44 56 and palmered (a) C Before Calendered 0.56 45 47 57 (a) C Calendered — 41 47 54 (a) C Calendered and 0.45 34 47 62 palmered (b) Not treated 0 62 58 68 (b) A Before calendered 0.44 53 55 54 (b) A Calendered — 40 43 45 (b) A Calendered and 0.46 40 40 47 palmered (c ) Not treated 0 28 32 42 (c ) A Before calendered 0.53 30 30 36 (c ) A Calendered — 28 29 34 (c) A calendered and 0.46 25 26 35 palmered It is clear that the tendency of all of these fabrics in Example XII to swell in either water or in 20$ NaOH has been reduced. Fabric (b) not treated, Gauge (Dry) is an artificially high value because this particular fabric wae in the fluffy condition . If it were in the normal compressed condition of the other fabrics, it would have had a gauge considerably below 58.

For significant reduction in the swelling of the fabrics, the fabrics usually contain a substantial amount of cellulose fibers, e .g. 10 or more , usually at least 20$ .

Examples XIII and XIV demonstrate the speed at which processing of fabric is possible . They also demonstrate the rapidity of the reaction which occurs under very favorable conditions .

EXAMPIE XIII Three lightweight white fabrics containing blends of 6 # polyester fiber and 3556 cotton fiber were processed through an aqueous mixture containing 1.0$ methyl carbamate , 6.0$ formaldehyde , Ο .8356 magnesium chloride , 0.8356 formic acid, Ο .55 acrylic polymer, comprising ethyl aery late , methyl methacrylate , acrylic acid and acrylamide (Rhoplex E-32) , 0.255& polyvinyl alcohol and Ο .256 nonyl phenpl -ethylene oxide condensate (wetting agent) followed by drying .

The three fabrics included: (a) a 125x72 3.70 yards/lb . (greige count and weight) broadcloth, (b) a 96x84 4.25 yards/lb . ^greige count and weight ) batiste , (c) a 94x80 .3 yards/lb . (greige count and weight ) batiste .

The polyester in fabrics (a) and (c) was Dacron, and in fabric (b) was Kode'i.

The wet pick-up by these fabrics when passed through the mix on a padder was in the range of 35 to 40$ .

Drying was accomplished on a tenter dryer with the air temperature regulated at 330°F . The speed of processing was 110 yards/minute and the fabric dwell time in the dryer was 14 seconds .

Fabric temperatures obtained as indicated by an infrared pyrometer (infrascope) were in the range from 25 to 255eF.

After drying, the fabrics were padded through a sodium bisulfite solution to remove unreacted formaldehyde and obviate 5 undesirable odors in the finished fabric (see U.S. Patent No. 2,870,041), washed and dried, a fatty acid based fabric softener was applied and dried into the fabrics, and the fabric was passed through a compressive shrinkage machine.

The fabrics were found to have fixed formaldehyde levels 10 as indicated which remained essentially constant through multiple laundering.

Formaldehyde Found ^ Fabric As (2) After 5 Home After 5 Sanforize After 5 Coraaerclal Sample Finished Launders (3) Washes (4) White Washes (5) a Ο.62 Ο.56 O.50 0.53 b 0.59 Ο.56 0.56 Ο.52 c Ο.62 0.61 Ο.62 0.61 On total weight of the fabric Scoured one hour at the boil in 1$ soda ash AATCC Tentative Test Method 88-1964T i One hour wash procedure. Starts near the boil. 160°F wash, chlorine bleach, zinc silicoflubride 37 minute cycle.

In addition, these fabrics had excellent wash-wear properties, retained a crisp hand through multiple laundering, remained white in multiple launderings while fabric not treated lost whiteness.

In a commercial laundering with colored garments, the untreated 15 fabric stained badly, while the treated fabric stained only slightly under such conditions.

EXAMPLE XIV The three fabrics of Example XIII were passed through a mixture containing 1.0$ methyl carbamate, 4.0# formaldehyde, 0.8¾6 20 magnesium chloride, 0.8¾6 formic acid, 0.556 acrylic polymer (Rhoplex E-32) , Ο.756 fatty acid based softener and 0.2# nonyl phenol -ethylene oxide condensate (wetting agent ) .

These fabrics were dried under similar conditions to those in Example XIII, except that the speed was 90 yards/minute and the fabric temperature as indicated by an infrared pyrometer was in the range from 250-260*F .

These fabrics were proce ssed after treatment as in Example XIII with bisulfite and softener, except that the mixture including the softener also included 1. # MgClg and 1. $ HCOOH .

Theee fabrics were Just bare ly dried after application of the mixture containing MgCl2 and HCOOH to prevent excessive loss of the acid .

These fabrics had the propertie s of the fabrics of Example XIII and also had the ability to retain a sharp crease after pressing and laundering . Thus , swatches of the fabrics were creased by pressing 15 seconds at a steam pressure of 100 psig in a Forse laundry press . The creases remained sharp and smooth throughout multiple laundering .

This example demonstrate s that the present invention can be utilized to impart durable shape retention and durable press to treated fabrics .

EXAMPLE XV A heavy (8.6 oz ./sq. yard) all cotton twill fabric which was previously mercerized and dyed was passed through an aqueous mixture containing : I .O56 methyl carbamate .<¾6 formaldehyde Ο .8356 MgCl2 Ο .8356 HCOOH I .O56 acrylic polymer (Rhoplex E-32) Ο . 56 polyvinyl alcohol Ο .256 nonyl phenol -ethylene oxide condensate (wetting agent ) The fabric was dried in a tenter dryer set at air temperature of 330°F . The fabric temperature was 230°F as measured by an infrared pyrometer. Dwe ll time in the oven was 21 seconds .

The fabric was then passed through an aqueous buffered catalyst mixture containing: 0.8¾6 MgCl2 0.8¾g HCOOH 0.50$ Na2s205 (sodium roeta bisulfite ) 2.556 emulsified tallow softener The fabric was dried in a tenter dryer set at an air temperature of 250°P . The fabric temperature was 190eF .

Swatches of the fabric were creased by pressing in a steam heated laundry press for 15 seconds at 100 psig steam followed by heating in a convection oven set at 32 eF for six minutes .

When these fabrics were given multiple washings, the creases were retained and appearance of the fabrics was excellent .

Similar results were obtained when the pressed fabrics were placed in a convection oven at 275 eP for six minutes .

As indicated in Example XV, for crease retention it is desirable to add further catalyst to compensate for the catalyst lost in the initial heating employed to dry the formaldehyde treated fabric . The crease retention properties are then Imparted after the initial cure of the fabric .

It will thus be seen that there has been provided by this invention a process and composition in which the various objects hereinbefore set forth, together with many practical advantages, are successfully achieved. As various possible embodiments may be made of the novel features of the above invention, all without departing from the scope thereof, it is to be understood that all matter hereinbefore set forth is to be interpreted as illustrative and not in a limiting sense .

Claims

HAVING EQW particularly described and ascertained^, he nature of our said invention and in what manner the same is to be performed, we declare that what we claim is: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process of fixing an aldehyde on a polymer of the group consisting of cellulose, cellulose esters and starch, comprising the steps of treating said polymer with an aqueous mixture containing a member of the group consisting of (1) an aldehyde to-gether with a carbamate having the formula ^ NCOOR where Rn and Ri^ R3 are selected from the group consisting of hydrogen, alkyl and carbocycllc aryl, and R2 is selected from the group consisting of alkyl and carbocycllc aryl, (2) an aldehyde-carbamate condensation product wherein the carbamate has the formula H2NC00R2, and (3) an aldehyde together with an aldehyde-carbamate condensation product wherein the carbamate has the formula H2NC00R2, and heating said treated polymer at a temperature sufficient to fix the aldehyde on said polymer but insufficient to cause any substantial nitrogen fixation.

2. A process according to claim 1 wherein the aldehyde is formaldehyde.

3. A process according to claim 2 wherein R^ and ^ are hydrogen and R2 is alkyl.

4. A process according to claim 1, wherein the aqueous treating mixture includes an acidic catalyst.

5. A process according to claim 1, wherein the aqueous treating mixture includes a latent acidic catalyst.

6. A process according to claim 1, wherein the aqueous treating mixture includes a basic catalyst.

7. A process of fixing formaldehyde on a polymer of the group consisting of cellulose, cellulose esters and starch, comprising the steps of treating said polymer with an aqueous mixture of formaldehyde and an alkyl carbamate, and heating said treated polymer to fix the formaldehyde on said polymer.

8. A process according to claim 7 wherein the alkyl carbamate is a lower alkyl carbamate.

9. A process of fixing formaldehyde on cellulose, comprising the steps of treating cellulose with an aqueous mixture of formaldehyde and an alkyl carbamate, and heating said treated cellulose to fix the formaldehyde on the cellulose.

10. A process according to claim 9 wherein the alkyl carbamate is a lower alkyl carbamate.

11. A process according to claim 10 wherein the alkyl carbamate is used in an amount of at least 0.1$ up to 5$ of the aqueous mixture.

12. A process according to claim 9 wherein the formaldehyde is used in an amount of from 3 to 60 moles per mole of carbamate .

13. A process according to claim 12 wherein the carbamate is methyl carbamate.

14. A process according to claim 13 wherein the heating is at a temperature of l80 to 300°P.

15. A process according to claim 12 wherein the carbamate is ethyl carbamate.

16. A process according to claim 15 wherein the heating is at a temperature of 180 to 300°P.

17. A process according to claim 9 wherein the cellulose is cotton.

18. A process according to claim 9 wherein the cellulose is regenerated cellulose. P.A.23476 Pile 13187 25.XII.68

19. A process according to Claim 9» wherein the degree of formaldehyde fixation on the cellulose is from 0.25 si.25 based on the weight of the cellulose, and the cellulose is in the form of cotton.

20. A process aocording to Claim 9, wherein the degree of formaldehyde fixation on the cellulose is from 0.5:2.5% based on the weight of the cellulose, and the cellulose is in the form of regenerated cellulose.

21. A composition of matter for use in a process as claimed in any of Claims 1 to 20, comprising an aqueous mixture of formaldehyde and an alkyl carbamate wherein the mole ratio of formaldehyde to carbamate is at least 3:1.

22. A composition according to Claim 21, which is substantially neutral.

23. A composition according to Claim 21, wherein the alkyl carbamate is a lower alkyl carbamate.

24. A composition according to Claim 23, wherein the mole ratio of formaldehyde to carbamate is from 3.5:1 to 100:1.

25* A composition according to Claim 2^ wherein the alkyl carbamate is methyl carbamate.

26. A composition according to Claim 23, wherein the alkyl carbamate is ethyl carbamate.

27. Cellulose, cellulose esters and starch with an aldehyde fixed thereon, whenever obtained by a process as claimed in any of Claims 1-20.

P.A.23476

Pile 13187 25.XII.68 29i A product according to Claim 28, wherein the regenerated cellulose is viscose rayon. - 26a -

A product according to claim 27 is cotton.

31. A process of reducing the swelling tendency of cellu-losic fibers in an aqueous medium comprising the steps of treating said fibers with an aqueous mixture containing a member of the group consisting of (1 ) an aldehyde together with a carbamate having the formula ^ NCOORg where R^ and R^ are selected from the group con- Rl^ sisting of hydrogen, alkyl and carbocyclic aryl, and R2 is selected from the consisting of alkyl and carbocyclic aryl, (2) an aldehyde-carbamate condensation product wherein the carbamate has the formula H2NC00R2, and ( 3) an aldehyde together with an aldehyde-carbamate condensation product wherein the carbamate has the formula H2C00R2, and heating said treated fibers at a temperature sufficient to fix the aldehyde thereon but insufficient to cause any substantial nitrogen fixation.

32. A product prepared by the process of claim 31.

33. A process according to claim 31* wherein the aldehyde is formaldehyde and the carbamate is an alkyl carbamate.

34. A process according to claim 31, wherein said fibers comprise a substantial percentage of regenerated cellulose fibers.

35 · A process according to claim 31* wherein said fibers comprise at least 35$ viscose rayon fibers.

36. A process according to claim 31 , wherein the alkyl carbamate is methyl carbamate.

37 - A process of fixing an aldehyde on a fabric comprising fibers of a polymer of the group consisting of cellulose and cellulose esters, comprising the steps of treating said fabric with an aqueous mixture containing a member of the group consisting of (1) R3 v an aldehyde together with a carbamate having the formula ^ NC00Ro where R^ and R3 are selected from the group consisting of hydrogen, alkyl and carbocycllc aryl, and R2 is selected from the group consisting of alkyl and carbocycllc aryl (2) an aldehyde-carbamate condensation product wherein the carbamate has the formula H2NC00R2, and (3) an aldehyde together with an aldehyde-carbamate condensation product wherein the carbamate has the formula H2NC00R2, and a catalyst for fixing the aldehyde to the fabric, heating said treated fabric at a temperature sufficient to fix the aldehyde thereon but insufficient to cause any substantial nitrogen fixation, to obtain a shape and crease retentive fabric.

38. A process according to claim 37 wherein the aldehyde is formaldehyde.

39· A process according to claim 38 wherein R^ and R3 are hydrogen and R2 Is lower alkyl.

40. A process according to claim 37, including the further step of adding additional catalyst to the treated fabric, drying the further catalyzed fabric and pressing and heating the fabric to obtain a shape and crease retentive fabric .

41. A process according to claim 40, wherein said catalysts are acidic catalysts.

42. A product prepared by the process of claim 37. DATED THIS 29th day of COHEH ZEDIK & SPISBACH P.O.BOX 1169, TEL-AVIV Attorneys for Applicants