Alkyl Polyglycosides in Textile Scour/Bleach Processing

The present invention generally relates to a composition and process for scouring and bleaching textile materials. More particularly, by combining an alkyl polyglycoside with an alkoxylated primary linear alcohol, a synergistic scouring and bleaching effect is realized. By adding a chlorine-capped ethoxylated isodecyl alcohol to the scouring and bleaching composition, reduced foaming is obtained.

Textile materials are among the most ubiquitous in society. They provide shelter and protection from the environment in the form of apparel, and comfort and decoration in the form of household textiles, such as sheets, upholstery, carpeting, drapery and wall covering, and they have a variety of industrial functions, such as tire reinforcement, tenting, filter media, conveyor belts, insulation, etc.

Textile materials are produced from fibers (finite lengths) and filaments (continuous lengths) by a variety of processes to form woven, knitted and nonwoven (felt-like) fabrics. In the case of woven and knitted fabrics, the fibers and filaments are formed into intermediate continuous-length structures known as yarns, which are interlaced by weaving or interlooped by knitting into planar-flexible sheetlike structures known as fabrics. Nonwoven fabrics are formed directly from fibers and filaments by chemically or physically bonding or interlocking fibers that have been arranged in a planar configuration.

Textile fibers are classified into two main categories, man-made and natural. Man-made fibers are formed by extrusion processes known as melt-dry, or wet spinning. The spinning or extrusion of filaments is normally followed by an operation known as drawing. In this step, the newly formed filaments are irreversibly extended and stabilized by setting or crystallization processes.

With the exception of silk, naturally occurring fibers have finite lengths and generally require several cleaning and purification steps prior to processing into yarns and fabrics.

There are a number of finishing processes that textile fibers are subjected to after their formation. The two with which the present invention is mostly concerned of sizing materials, lubricants and other impurities which are contained in and/or adhere to the fibers during their formation. These various impurities must be removed so that the textile fibers may be further processed. Another finishing process is bleaching whereby a white color is imparted to the fabric. This bleaching step also enhances the absorbency of the fiber materials in preparation for the application of other finishing processes as well as the removal of any residual impurities left over from the scouring process.

Both the scouring and bleaching processes are performed under extremely alkaline conditions using high concentrations of peroxide and/or caustic soda, and at high temperatures. Due to the extremely hot and alkaline environment, there is a need for a textile scouring and bleaching composition which is stable under these circumstances, while at the same time having low levels of foam formation under high agitation. Moreover, as a result of the current degree of enhanced consciousness with respect to the protection of our environment, the composition employed should be highly biodegradable as well.

Thus, it is a primary object of this invention to provide a more effective means of scouring and bleaching textile fibers in an environmentally safe manner.

Another aspect of the present invention is reduction in the generation of foam associated with the use of alkyl polyglycoside surfactants. It is known that alkyl polyglycosides exhibit significantly higher foaming profiles than other nonionic surfactants such as alcohol ethoxylates. In fact, it can be said that the foaming tendencies of alkyl polyglycosides more closely resemble those of anionic surfactants such as alcohol sulfates than the foaming tendencies of other nonionic surfactants. The higher foaming tendency of alkyl polyglycosides makes their use in certain types of applications disadvantageous. For example, spray washing with aqueous cleaning composition applied from high pressure nozzles can produce significant amounts of foam; thus, the surfactant used in these cleaning operations must have a minimum foaming tendency. Foaming problems can also arise when high foaming surfactants are used with floor cleaning machines. Consequently, users of alkyl polyglycosides are always looking for methods of decreasing the foaming tendency of aqueous alkyl polyglycoside compositions without simultaneously affecting the beneficial properties of the alkyl polyglycosides such as cleaning ability. It is, therefore, another object of the present invention to reduce the foaming tendency of aqueous alkyl polyglycoside compositions.

Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about".

Briefly stated, the present invention is directed to a composition and process for scouring and bleaching textile materials while controlling foam generation comprising adding to an aqueous peroxide bleaching bath a foam-suppresing effective amount of a surfactant composition comprising:

(a) from about 6% to about 94% by weight of an alkyl polyglycoside having the general formula I

wherein R is a monovalent organic radical having from about 8 to about 16 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; and a is a number having a value from about 1 to about 6,

(b) from about 94% to about 6% by weight of a synthetic alkoxylated C.sub.8 -C.sub.15 linear alcohol, and

(c) the remainder water, all weights being based on the weight of the composition, and then contacting said textile materials with said bath.

Preferably, the surfactant composition comprises:

(a) from about 6.0% to about 94.0% by weight of an alkyl polyglycoside having the general formula I

wherein R is a monovalent organic radical having from about 8 to about 16 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; and a is a number having a value from about 1 to about 6,

(b) from about 94.0% to about 6.0% by weight of a synthetic alkoxylated C.sub.8 -C.sub.15 linear alcohol, or

(c) from about 94.0% to about 6.0% by weight of a chlorine-capped ethoxylated isodecyl alcohol, and

(d) the remainder water, all weights being based on the weight of the composition, and then contacting said textile materials with said bath.

It has surprisingly been found that an exceedingly synergistic scouring and bleaching effect can be obtained for a wide variety of textile materials when combining the alkyl polyglycoside surfactant of this invention with a synthetic primary linear C.sub.8 -C.sub.15 alcohol that has been alkoxylated. It has also been found that foam generation of such a surfactant composition can be reduced or controlled by addition thereto of a chlorine-capped ethoxylated isodecyl alcohol..

The aqueous peroxide bleaching bath typically contains finishing components present in an amount of from about 5.0 to about 20.0% by weight, based on weight of the bath. These finishing components include an alkali material, caustic soda, chelating agents and a surface-active material such as a surfactant. It is preferred that the composition be phosphate-free and contain no phenols.

The alkyl polyglycoside of the present invention is of the general formula I:

wherein R is a monovalent organic radical having from about 8 to about 16 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; and a is a number having a value from about 1 to about 6.

The alkyl polyglycosides which can be used according to the invention preferably contain from about 12 to about 16 carbon atoms. These alkyl polyglycosides are commercially available, for example, as GLUCOPON.RTM. 325 and GLUCOPON.RTM. 600 from Henkel Corporation, Ambler, Pa.

The alkyl polyglycosides have a dipole moment in the range of about 1.4 to about 1.7, and preferably about 1.4. the pH of the alkyl polyglycoside is preferably in the range of about 8 to about 9. The percent actives of the alkyl polyglycosides employed in the present invention is in the range of about 40 to about 70, and preferably about 50%.

The alkoxylated primary linear alcohols of the present invention are the condensation products of organic C.sub.8 -C.sub.15 alcohols with from about 6 to about 7 moles of ethylene oxide and from about 3 to about 6 moles of propylene oxide, per mole of alcohol. These alkoxylated alcohols preferably have an HLB value of from about 7.0 to about 8.5. An example of a commercially available alkoxylated alcohol of this type is TRYLON.RTM. 6735, marketed by Henkel Corporation, Textiles Division, Charlotte, N.C. The chlorine-capped ethoxylated isodecyl alcohol preferably contains from about 6.0 to about 10.0 moles of ethylene oxide such as commercially available from Henkel Corporation, Textiles Division, Charlotte, N.C. under the tradename SYNTERGENT.RTM. CSW.

The amount of alkyl polyglycosides and alkoxylated synthetic alcohol or chlorine-capped ethoxylated isodecyl alcohol to be used should be sufficient to effectively wet, i.e., impregnate the textile substrate and thus aid to scour the substrate and improve the bleaching properties of the bath. The types of substrates which will be treated with the bleaching and scouring composition will vary, but will include articles of apparel made of cotton and polyester/cotton woven and knit goods.

In a particularly preferred embodiment of the present invention, the composition to be added to the aqueous peroxide bleaching bath contains from about 20 to about 60% by weight of the alkyl polyglycoside and from about 80 to about 40% by weight of the synthetic alkoxylated linear alcohol or chlorine-capped ethoxylated isodecyl alcohol. Also, the amount of the surfactant composition to be added to the bath is typically in the range from 0.1 to 1.0% by weight, based on the weight of the bath, and preferably from about 0.1 to about 0.2% by weight.

Generally, the continuous scouring and bleaching process for cotton and polyester/cotton woven goods is carried out in two separate steps, and in either rope or open-width form using an exhaust bath.

In the scouring step, the pH of the alkaline aqueous impregnation (exhaust) bath is most preferably between about 11 and 12 and the temperature of the bath is preferably between about 120.degree. F. and 200.degree. F., and most preferably about 160.degree. F. The desized fabric is immersed in the alkaline scour bath and squeezed, by pad rolls, to a wet pickup of from about 90% to 110% owg (i.e. on the weight of the goods). The treated fabric is then placed in a steam chamber for about 15 minutes (to simulate the open-width process) or about 60 minutes (to simulate the rope process). The steamed fabric is then washed in water at a temperature from about 180.degree. F. to 200.degree. F., for about 60 to 90 seconds.

In the bleaching step, the pH of the alkaline aqueous bleaching/exhausting bath is preferably between about 10.8 and about 11.2, and most preferably about 11.0. The temperature of the aqueous bath is preferably between about 75.degree. F. to about 120.degree. F., and most preferably about 100.degree. F. The scoured fabric is impregnated with the aqueous alkaline bleaching bath in the same manner as in the scouring process above. The treated fabric is then steamed in the same manner as disclosed above for the scouring process. The steamed fabric is then washed in water at a temperature of about 180.degree. F. to 200.degree. F., for approximately 60 to 90 seconds, followed by a cold rinse in water containing acetic acid to neutralize any residual alkali that may be present. The washed fabric is then dried at about 250.degree. F.

The continuous scouring and bleaching process for cotton and polyester/cotton knit goods may also be performed per the one-bath under liquor method. The pH of the bath is preferably between about 10.8 and 11.2, and most preferably about 11.0. The temperature of the aqueous bath is preferably about 185.degree. F. with the dwell time being about 30 to 45 minutes. This step is followed by washing at about 160.degree. F. to 185.degree. F. for approximately 15 to 20 minutes. It should be noted, however, that the pH and temperature ranges are dependent on a number of variables including the type of substrate being treated.

Another method of applying the aqueous bath is known as a padding operation, i.e., using a padding bath, whereby the bath is padded or blotted onto the substrate. This operation is very similar to that of a continuous dyeing operation since the substrate is mechanically carried into and out of the padding apparatus. When employing the padding bath, the aqueous scouring and/or bleaching bath will have a pH in the range of about 11.0 to 12.0, and preferably in the range of about 10.8 to 11.2. It should be noted, however, that either the exhaust bath or padding bath may be employed to scour and/or bleach the fabric when using the composition of the present invention.

It has also been surprisingly discovered that the foaming tendency of an aqueous alkyl polyglycoside formulation can be significantly reduced by incorporating an effective amount of a chlorine-capped ethoxylated isodecyl alcohol into the formulation. The chlorine capped ethoxylated isodecyl alcohol may contain from about 6 moles to about 10 moles of ethylene oxide per mole of alcohol, but preferably contains from about 9 moles to about 10 moles of ethylene oxide per mole of alcohol. Such compounds are commercially available from, for example, Henkel Corporation under the tradename SYNTERGENT.RTM. CSW. The effective amount of a chlorine-capped ethoxylated isodecyl alcohol required to reduce the foam in an aqueous alkyl polyglycoside solution will depend upon the end use of the composition. Typically, the effective amount will be any amount necessary to reduce the foam in an aqueous alkyl polyglycoside solution to a desired level and will be readily determinable by the person of ordinary skill in the art. The chlorine-capped ethoxylated isodecyl alcohol can be incorporated into an aqueous alkyl polyglycoside composition by any means known to those skilled in the art.

The addition of a chlorine-capped ethoxylated isodecyl alcohol into an aqueous alkyl polyglycoside composition reduces the foam without a concomitant reduction in the cleaning ability of the composition. Very effective foam reduction in an aqueous composition comprised of an alkyl polyglycoside in which the alkyl group contains 8 to 10 carbon atoms and having an average degree of polymerization of 1.7 is achieved without a concomitant reduction in the cleaning ability of the composition by adding thereto a chlorine-capped ethoxylated isodecyl alcohol.

FIG. 1 is a bar graph illustrating the degree of foam generated by various blends of GLUCOPON.RTM. 600 CS AND TRYLON.RTM. 6735, by measuring the height of foam formed after 2 minutes, at a temperature of about 120.degree. F.

FIG. 2 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS AND TRYLON.RTM. 6735 on caustic stability, represented by sodium hydroxide content, at a temperature of about 160.degree. F.

FIG. 3 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS AND TRYLON.RTM. 6735 on Draves wetting speed using a cotton substrate.

FIG. 4 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS AND TRYLON.RTM. 6735 on bleached whiteness using the Gardner Whitness test.

FIG. 5 is a bar graph of foam height versus time for various weight ratios of GLUCOPON.RTM. 600 CS AND SYNTERGENT.RTM. CSW (chlorine-capped ethoxylated isodecyl alcohol) by measuring foam height after 2 minutes at a temperature of about 120.degree. F.

FIG. 6 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS AND SYNTERGENT.RTM. CSW on caustic stability, represented by sodium hydroxide content, at a temperature of about 160.degree. F.

FIG. 7 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS and SYNTERGENT.RTM. CSW on Draves wetting speed using a cotton substrate.

FIG. 8 is a bar graph illustrating the effects of various blends of GLUCOPON.RTM. 600 CS and SYNTERGENT.RTM. CSW on bleached whiteness using the Gardner Whiteness test.

The present invention will be better understood when read in light of the following examples. In the following examples, parts and percentages are by weight and the temperatures are in degrees Celsius.

In the examples, the following five test methods were used to evaluate the effectiveness of the scouring and bleaching composition:

I. Whiteness Measurement

Procedure

(1) Desized, scoured cotton or polyester/cotton woven goods were immersed in the aqueous bleaching and scouring composition and squeezed, by pad rolls, to a wet pickup of 90-110% owg (on the weight of the goods).

2) The treated fabric was then placed in a steamer for about 15 minutes (to simulate open-width bleach) or 60 minutes (to simulate rope bleach).

(3) The steamed fabric was then washed in water at about 180.degree. F. to 200.degree. F. for approximately 60 seconds. This washing process was then repeated and followed by a cold rinse in water containing acetic acid to neutralize any residual alkalinity.

(4) The washed fabric was then dried at about 250.degree. F.

Evaluation Method For Whiteness

The bleached and scoured fabric was then evaluated using a Gardner reflectometer to measure whiteness.

2. Foam Measurement

Bleach baths (see Comparative Examples) were tested for foam propensity using either a scour bath formulation or bleach bath formulation. The test apparatus was a recirculating foam tester that sprays the bath onto the surface of the bath held in the reservoir. For this particular test, the foam measurement was performed using a recirculation pump foam tester at 70 volts, at 120.degree. F. for 60 seconds.

3. Wetting Property Measurement:

Draves Test

Performed using AATCC-17-1989.

4. Cleanliness (% Extractibles)

Performed using: (1) Enzyme and water, and (2) perchloroethylene (AATCC-97-1989).

5. Caustic Stability

Performed using 10 g/l test sample in 50% caustic soda solution, at 160.degree. F.

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

(a) TRYLON.RTM. 6735, commercially available from Henkel Corporation, Textile Division, Charlotte, N.C. is a 12-15 carbon chain length synthetic linear alcohol sold under the trade name NEODOL.RTM. 25, available from Shell Oil Co, which is reacted with 5 moles of propylene oxide and 7 moles of ethylene oxide.

(b) GLUCOPON.RTM. 600 CS, commercially available from Henkel Corporation, Ambler, Pa., is an alkyl polyglycoside composition having 12 to 16 carbons and an average degree of polymerization of 1.4.

The components listed above and in the following examples were mixed together in a vat at a temperature of about 50.degree. C. under agitation.

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

(b) GLUCOPON.RTM. 325 CS, commercially available from Henkel Corporation, APG Division, is an alkyl polyglycoside composition having 9 to 11 carbon atoms and an average degree of polymerization of 1.6.

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

A surfactant composition for use in a textile scouring and bleaching bath was prepared having the following components:

A surfactant composition for use in a scouring and bleaching bath was prepared having the following components:

SYNTERGENT.RTM. CSW, commercially available from Henkel Corporation, Textile Division, Charlotte, N.C., is a 10 carbon atom chain length isomeric alcohol which is reacted with about 6 to about 10 moles of ethylene oxide and capped with thionyl chloride.

A surfactant composition for use in a scouring and bleaching bath was prepared having the following components:

A scouring and bleaching composition was prepared having the following components:

*STANDAPOL.RTM. 617 is an organic peroxide stabilizer.

*SYNTERGENT.RTM. WOR is a (15%/36%/wt) blend of 2-ethylhexyl ether phosphate, potassium salt, and TRYLON.RTM. 6735.

Examples 1-8 and Comparative Example C1 were used to scour and bleach cotton substrates by impregnation with an aqueous peroxide bleaching bath having a pH of about 11.0, followed by steaming at a temperature of about 98.degree. C. for a period of about 60 minutes.

Each sample was evaluated per the above stated testing methods for whiteness, foam formation, alkali stability, wetting properties and cleanliness, i.e., % Extractibles, the results being set forth in Table I.

From the foregoing evaluation results and the bar graphs of FIG. 1-8, it can be seen that the bleaching and scouring process of this invention synergistically provides excellent whiteness to fabric materials, low residual impurities, is stable in high temperatures, is very low-foaming under high agitation conditions, and is biodegradable, thus avoiding pollution concerns.