US3350161A - Bleaching cottons by aqueous solutions of urea peroxide - Google Patents

Description

United States Patent Office BLEACHIN G This application is a continuation-in-part of application S.N. 804,591, filed Apr. 7, 1959, now forfeited.

The present invention relates to the bleaching of fabric materials and it particularly relates to the bleaching of textile materials.

It is among the objects of the present invention to provide improved bleaching procedures for various types of textile material, whether in yarn or fabric form, and which may be readily applied, either in commercial application in the dye or bleach house or even in the home.

Another object is to provide new textile bleaching arrangements and operations which are particularly suited for bleaching cellulosic fabrics which will not undesirably aflfect other types of finishes and which will leave the finish in hand unaffected without any decrease in strength or effect upon fabric strength.

Another object is to provide a bleaching system which will be effective to bleach various types of finished textile fabrics without affecting the hand or texture thereof, while at the same time it is possible to carry out other operations in connection therewith.

Still further objects and advantages will appear in the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration and explanation only and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

It has been found that urea peroxide is a most effective bleaching agent for cotton yarn or cotton fabrics, even if the cotton is mixed with other fibers and even if the cotton has been finished or dyed.

Urea peroxide may be used in relatively small concentrations, ranging from .5% to 8% and sometimes as much as 10% of the bath, to give aparticularly effective whitening or lightening effect, with or without the addition of brighteners or other agents.

It is found that these dilute urea peroxide solutions having a pH of to 7, with small amounts of weak acid such as acetic acid may beemployed even with finished garments, as well as finished fabrics, without undesirably affecting the dye or other finish, which may be applied thereto and with retention of all the quality of the fabric.

The urea peroxide appears to enhance the action of nonionic surface active agents, which may be used in very small quantities or eliminated with the urea peroxide accomplishing the lightening or brightening effect, with the susbtantially complete removal of soil.

The urea peroxide also may be used with anionic surface active agents with a great reduction of said anionic agent, particularly Where soap is employed, without any weakening of the fabric structure.

A particularly unusual effect arises from the great increase in sudsing properties, which is accomplished even .With poorsudsing detergents of synthetic or.soap char- ,acter.

A particularly satisfactory result is that in M1 to /2 of the normal bleaching and washing period a better 3,350,161 Patented Oct. 31, 1967 whitening and lightening effect is achieved with substantially complete soil removal.

It has been found that with synthetic fabric and yarn, the sodium chlorite may be used to achieve most satisfactory bleaching with a minimum of exposure time and to give a particularly satisfactory whiteness to the fabrics.

The operation may be carried out by beam bleaching in which the beam or large spool of yarn is bleached directly, such beam on large spools of yarn being used for weaving a piece of cloth.

Normally, the beam will contain several hundred pounds of yarn which are bleached in a sealed machine so that the bleached liquor may be circulated throughout the yarn to obtain even bleaching or dyeing. Usually, in beam bleaching about ten to fifteen times as much liquor is utilized in the system as the Weight of the yarn and the percentage of the urea peroxide in the bath will vary from 0.2 to 10% based on the weight of the yarn itself.

The urea peroxide bleaching solution may also be used in a beck which is a machine equipped for handling fabrics in a slack rope form so as not to damage or bruise them during bleaching or dyeing.

In a beck, the volume of liquor per weight of cloth runs considerably higher than in beam bleaching, with as much as 20 to 30 pounds of liquor being used per pound of cloth.

The percentage about 0.2 to 10% being treated.

With such a beck or box machine, patches or small samples of cloth may be taken out to check the bleaching or depth of shade of the cloth being processed.

These box or beck machines may also be provided with saturators which are a set of squeeze rolls mounted above the box or beck containing 50 to yards of yarn of urea peroxide utilized will again be based upon the weight of the fabric or fabric to make certain that the liquid will be pressed into the interstices. The urea peroxide solution may also be used for bleachmg on a igg.

A jigg is a small batch machine which carries approximately a 500 pound roll of cloth through a solution weighing approximately ten times as much as the roll of cloth.

the urea peroxide percentage may vary from 0.2 to 10%.

The jigg machine may be used for a wide variety of fabrics, and the cloth is usually run through the jigg bath from one end of the roll to the other or end to end.

Frequently, it may be sufficient to provide two ends of the treatment, that is to run the goods twice through the jigg bath from one end of the roll to the other although three, four, or five more'ends may be run each representing running the goods from one end of the roll to the other.

The same may be done with washing on the jigg where again there may be two or more ends of wash which means that the 'goods are run from end to end of the wash 3 flowing inside out which means flowing from the center of the beam through the perforations to the outside of the beam to the pump. Then it may flow outside in with the liquor flowing from the outside of the beam through the yarn and through the center spindle back to the rear side of the pump.

These inside out and outside in beam bleaching machines are automatic and have automatically actuated reversing valves which change the flow of liquid every few minutes.

In beam bleaching, it is usually desirable to get strings which means that strips of the yarn are removed from the beams to check the bleaching and determine whether it is taking place satisfactorily as the urea peroxide is circulated therethrough.

Where urea peroxide is utilized by itself without caustic, it is usually unnecessary to neutralize or acidify but where caustic soda is employed to prevent yellowing of the fabric, it is necessary to add acetic acid to neutralize the caustic.

Ordinarily such souring or neutralization may be done with any of the common organic acids but acetic acid is preferred since it is least expensive and the minimum quantity of the acetic acid is utilized to effect neutralization and to give a pH of 7.

Where, however, the temperature is elevated giving a likelihood that the acetic acid may be volatilized in neutralizing an alkali, oxalic acid may be used.

Usually, the urea peroxide and particularly when urea peroxide is used by itself, the bleaching should take place on the alkaline side at a pH range of about 8 to 12 and where desirable, an increased temperature may be employed.

Desirably, with urea peroxide formations, a nonionic detergent should be utilized in amounts of about 2 to together with an optical whitener particularly with cellulose fibers inthe same quantities.

These nonionic detergents are particularly useful in beck, beam and jigg bleaching, but with home washing machines, it is desirable to utilize similar quantities of anionic detergents.

It is also possible to use a swelling agent where dyestuffs are to be applied or stripped from the yarn or textile fabric, and these swelling agents may be used either to carry the dye away from the fiber or to apply it to the fiber.

These swelling agents may be used in a smaller quantity ranging from /2 to 3%.

Where resinous finishes are used such as to give washand-wear effects, it has been found that the urea peroxide solution also has the effect of removing and oxidizing the formaldehyde and eliminating any formaldehyde odor resulting from the treatment with triazone or similar resins.

The urea formaldehyde solution is readily applicable to mixed fabrics.

Typical fabrics which may be treated are rayon-acetate ,suitings including flannel suitings, and in this case, a

combination dyeing and bleaching process may be employed in which the viscose rayon would be dyed black and the acetate would be bleached white.

With rug materials, desirably warm water should be utilized starting at a temperature of 120 F. and gradually increasing to 160 F.

Where the urea peroxide solution is used for home bleaching and washing machines, it is usually regulated to correspond to the load of fabrics from 8 to 10 pounds with an ultraviolet brightener agent being used in small amounts.

To give a series of examples illustrating the applications of the present invention:

EXAMPLE I Bleaching of cotton yarn on beams In the bleaching of cotton yarns on beams, a beam of 253 pounds with 13/1 carded yarn is placed in a machine which is filled with cold water, with the machine first run 5 minutes inside-out.

Then the 25% of aqueous detergent solution containing 10 ounces of nonionic detergent is run 5 minutes outside-in and 15 minutes insideout.

Next there is added a 3% solution containing 7 pounds and 10 ounces of urea peroxide and a 2% solution containing 5 pounds of caustic soda flakes run outside-in over a 5 minute period.

The temperature is then raised slightly over a 20 minute period, with a series of 5 minute runs, the first 5 minute run being inside-out at F., the second run being for 5 minutes outside-in at F., the next run being for 5 minutes inside-out at F. and the last run being for 5 minutes outside-in at F.

The next succeeding step then involves two successive runs at 180 and a 10 minute run inside-out at 180.

Then the machine is drained with a hot running wash being carried on for 10 minutes inside-out.

The machine is refilled with hot water at 180 F. and a 0.67% solution containing 2 pounds of acetic acid of 84% concentration is added, with a 5 minute run outsidein and a second 5 minute run inside-out.

Then the machine is drained, followed by a cold running wash for 10 minutes.

Finally the beam is extracted if it is not to be dyed and any strings are removed.

This entire operation, which should not take over 90 minutes, will give a very bright, light cotton yarn having a smooth handle and unaffected as far as strength is concerned, with a saving of time from 2 to 3 or more hours and with the production of a superior product.

It will be noted that the urea peroxide was only used for about 20 minutes to achieve this result, at varying temperatures from 120 to 180, in the presence of caustic soda and with a pH of 8 to 11.

EXAMPLE II Bleaching cotton knit goods with urea peroxide The knit goods are placed in a bleach tub with a liquor ratio of 20:1 and with all percentages based on the weight of the goods.

The bath is then boiled for 20 minutes with 5% caustic soda and 3% sodium hydrosulfite, followed by rinsing with warm water. Then the bath is treated for 30 minutes at 180 to with 2% of urea peroxide, 1% of sodium chlorite and 0.4% of oxalic acid.

Then the pH is adjusted to 10 or above with caustic soda and the bath is run for 30 minutes longer, followed by rinsing, souring, rinsing, and then with another run of 20 minutes at 160 F. with 0.025% of an ultra-violet brightener.

The resultant knit goods had a superior hand and texture and were not at all unduly affected as, far as strength was concerned.

EXAMPLE III- Treatment of cotton yarn Cotton yarn of the count 8/2 is treated in a liquor ratio of 20:1 with all percentages based upon the weight of the yarn.

The cotton yarn is first run for 30 minutes at 180 to 190 F. with 2% of urea peroxide, 1% of sodium chlorite and 0.4% of oxalic acid, without adjustment of the pH.

Then the pH is adjusted to 10 or above with caustic soda and is run for 30 minutes longer, followed by rinsing, sou-ring with acetic acid, rinsing and drying.

This operation saved at least 45 to 90 minutes and produced a superior cotton yarn.

EXAMPLE IV Treatment of cotton yarn Cotton yarn of the count 14/1 is treated in a liquor The aqueous bath is first run for 30 minutes at 190 to 200 F., containing 2% urea peroxide, 2% sodium chlorite, 0.4% oxalic acid, without adjustment of the pH.

Then the pH is adjusted to 11 to 12, with caustic soda and the aqueous bath is run 30 minutes longer.

This is followed by rinsing, souring with acetic acid, and rinsing again.

Then the bath is run for 20 minutes at 160 F. with 0.2% of an ultra-violet whitening agent.

The resultant yarn was of superior quality with a great saving of time.

EXAMPLE V Bleaching of cotton duck Cotton duck in a quantity of 500 yards is immersed in an aqueous both containing by volume 1% of urea peroxide, 1% of 33% aqueous caustic soda solution, Ai% of a nonionic detergent. The pH was adjusted to 13 and the temperature was adjusted to 190 F.

Four ends were run on a jigg for 45 minutes with a running hot water bath at 160 F. Then the four ends were run through cold water followed by drying.

The duck was bleached to the desired degree of perfection without any change in its other properties and with no retention of bleaching agent.

EXAMPLE VI Bleaching cotton duck EXAMPLE VII Jigg applications It has been found that urea torily utilized with jiggs.

In a jigg the following aqueous bath is made up, based upon the weight of the goods, containing the following peroxide is very satisfacingredients Percent Sodium chlorite solution (50%) 1 Oxalic acid 0.2 Urea peroxide 1 Caustic soda (100%) 2 Nonionic detergent 0.125

In forming this bath, desirably the nonionic detergent is first dissolved in 100 gallons at 100 to 110 F., after which the dissolved 50% sodium chlorite solution is added.

The goods are then run one end for 15 to 30 minutes.

Then one-half of the urea peroxide is added, which has been previously dissolved in warm water and the goods again are run one end and the balance of the urea peroxide is added.

Then the oxalic acid is added and the temperature is gradually raised to 180 F.

The goods are given six ends at 6 minutes per end, after which the caustic soda previously dissolved is added and the goods are given six additional ends.

The bath is then pumped, followed by two ends of hot wash.

Then the bath is dropped, followed by two ends of hot wash, with /2 of 56% acetic acid solution.

Finally, the goods are given two ends, are rinsed in the cold, and shelled up.

6 EXAMPLE VIII Beck bleaching of cotton Five thousand yards of 136 x 60 combed broadcloth are run on a 15 foot beck with the following formulation:

Urea peroxide-420 pounds Nonionic detergent--60 pounds 50% aqueous caustic soda solution In making up the bath, the nonionic detergent and the caustic soda are added to the beck with gradual heating to 140 F. and while loading.

After heating to 140 F., and after loadingthe becks, the urea peroxide is dissolved in 40 gallons of warm water, and this solution is added.

Then the temperature is raised to 175 F. at a rate of 2 degrees a minute and the beck is run for 60 minutes and patched.

EXAMPLE IX Bleaching of cotton back fabrics A toy plush fabric having a rayon pile and a cotton back, in the amount of 350 pounds of fabric averaging 1 yard per pound is placed in a dye beck carrying 600 gallons of water.

The machine is loaded and a nonionic or anionic detergent is added in the amount of 2% to 3%, based upon the weight of the fabric.

Then a solution of urea peroxide containing 1%. grams per liter, together with a solution of 50% sodium chlorite, containing 1 /2 grams per liter, is added to give respective concentrations of 3% to 3% of the urea peroxide and the sodium chlorite.

The aqueous bath is then brought to a boil and the 1 gram per liter of oxalic acid is added to give a 2% concentration of the, oxalic acid followed by running for 30 minutes at the boil.

Then 2 gallons of liquid caustic soda of 50% concentration is added, followed by addition of 0.9 pound of optical bleach for the 600 gallon composition. The bath is then adjusted to a pH of 12 to 13 and is boiled for 30 minutes.

An excellent bleach was obtained without undesirably affecting the hand or quality of the plush and without affecting the strength of the cotton backing.

EXAMPLE X Bleaching of cotton and synthetic mixtures In the bleaching of cotton and synthetic mixtures, such as cotton-cotron mixture, a bath of gallons containing the following additions may be utilized, based upon the weight of the bath:

Percent Urea peroxide 3 Caustic soda 1 /2 Nonionic detergent /2 Chelating agent .05

This bath was maintained at room temperature for one hour and then elevated to 215 F. for another hour.

A very satisfactory white was produced.

EXAMPLE XI Beck bleaching of synthetic fabrics was added to the beck. Then the temperature was raised to 180 F. and the material was run for 30 minutes.

Finally the material was dumped and washed with 3 hot rinses.

EXAMPLE XII White wash laundering One load of 300 pounds of white goods was processed in a prosperity type stainless steel washer wheel.

The goods were given 3 successive 8 minute suds treatments with flush, soap and draining between the suds treatments. Then 4 suds treatments consisting of 600 cc. of a solution of 4 pounds of urea peroxide and 5 gallons of water containing 2 pounds of soda ash.

All of these 4 cycles were run at 150 F., and finally the goods were given 4 rinses, 1 at 8 minutes at 180 F. followed by dumping; a second of 8 minutes at 160 F. followed by dumping; a third at 80 F. followed by dumping; and a fourth of 8 minutes including a blue and sour cold treatment.

A most satisfactory whitening of the goods was achieved without loss in strength.

EXAMPLE XIII Stripping procedure utilizing urea peroxide It was found that material may be stripped and bleached with the use of urea peroxide. This is accomplished by use of a bath containing 100- parts of water in which there are 5 parts of urea peroxide, 5 parts of 50% caustic soda solution, 1 part of a nonionic detergent, and 2 parts of a stripping agent.

The fabric, when boiled in such a bath for 30 minutes, resulted in stripping the dyestutf and simultaneous bleaching of the fabric.

EXAMPLE XIV Simultaneous bleaching of nylon and acetate tricot with urea peroxide A tricot fabric composed of nylon and acetate was immersed in a bath containing 2 /2 grams per liter of urea peroxide and 2 /2 grams per liter of a 50% compound of sodium chlorite.

The bath was first prepared in the cold and the temperature was raised to a boil, following which 2 /2v grams per liter of oxalic acid were added.

The process was then continued for 35 minutes and the pH was brought up to 9 with tetra sodium pyrophosphate.

Then the bath was run for 30 more minutes and washed A very satisfactory bleach was achieved.

EXAMPLE XV Use of urea peroxide to improve fabric treating with resin finishing A mixing tank was made up containing 10% of a combination of resins including 1,000 pounds of triazone resins, 10 pounds of urea peroxide and 20 pounds of water.

The mixing tank was first charged with the triazone resins, then urea peroxide was added dissolved in water with 2 parts by weight of water for each part by weight of urea peroxide.

The mixture was permitted to stand for 24 hours and it was found that all free formaldehyde had been removed and the product was free of any excess formaldehyde.

EXAMPLE XVI Bleaching of rayon acetate blends In bleaching rayon acetate blends, 2,400 yards of a rayon and acetate flannel suiting fabric and dyed with direct black dye were placed in a 16 foot beck at a 20:1 ratio.

aqua ammonia concentration at F.

The bath was then run for 20 minutes and the fabric was washed.

The acetate rayon was of a highly improved white and sodium hydrosulphite was not required.

EXAMPLE XVII Bleaching rug material Rug material was bleached in a paddle machine with a 20:1 liquor ratio. The following percentages were added, based upon the weight of the goods, namely:

Percent Caustic soda 5 Urea peroxide 5 Nonionic detergent 1.25

The goods were wet out for 5 minutes in warm water containing the nonionic detergent.

Then the urea peroxide was added, dissolved in warm water and the mass was run for 5 minutes. Then a solution of caustic soda was added and the temperature was gradually raised from 140 to F. and run for 30 minutes.

The bath was dropped and the goods were given a hot running rinse and then soured in 0.25 acetic acid. The fabric was finally rinsed in cold running water and finished.

This treatment is particularly satisfactory for rayon material in a paddle machine.

EXAMPLE XVIII Laundry bleach procedures To give a laundering bleach procedure which may be used domestically or in commercial laundries, a combination may be made up of:

3% by weight of urea peroxide .25 of acetanilide .25 of ultra-violet brightening agent 96.5% of water at room temperature with the pH being adjusted to 5.0 to 5.5.

It was found that a solution of this concentration may be most conveniently added in the amount of 6 ounces to a 30 to 50 pound load.

This solution will not harm fast colors and will give white goods an enhanced brightness 'and is particularly adapted to wash and wear and mixed fabrics containing cotton, wool, nylon and Dacron. The mixture may be added to with a regular detergent or soap without affecting the detergent actionI This type of solution may also be very effectively used for removing stains and spots on fabrics upon being 10- cally applied, followed by using a regular laundering operation.

As many changes could be made in the above bleaching procedures, and many widely different embodiments of this invention could be made without departure from the scope of the claim, it is intended that all matter contalned in the above description shall be interpreted as illustrative and not in a limiting sense.

Having now particularly described and ascertained the nature of the invention, and in what manner the same is to be performed, what is claimed is:

A process of bleaching cotton duck which comprises treating it in an aqueous bath containing by volume 1% of urea peroxide, and 1% of 33% aqueous caustic soda at a pH of 13 and a temperature of F.

(References on following page) 9 10 References Cited OTHER REFERENCES UNITED STATES PATENTS Baier: Alien Prop. Cust. No. 250,850, pub. July 13,

=8/19'12 Stanek 260-553 1943- 7/1928 Jones. 10/1933 Lehner et a1. 8 110 5 I. TRAVIS, BROWN, Acting Primary Examiner. 4/1939 Frenkel 8111 X MORRIS O. WOLK, NORMAN G. TORCHIN, 2/1946 Woodhouse et a1. 8-110 X Examiners.

F. CACCIAPAGLIA, H. WOLMAN, I

FOREI N PATENTS Assistant Examiners.

3/ 1942 Germany. 0