AU7743598A - Treatment of fabrics - Google Patents

Description

p 00! Oil Regulation 3.2 P/00/011 .R.gtilation

AUSTRALIA

PATENTS ACT 1990 COMPLETE

SPECIFICATION

FOR A STANDARD

PATENT

ORIGINAL

.tb TO BE COMPLETED BY APPLICANT

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j Name of Applicant: Actual Inventor s: Address for Service: invention Title, IMPERIAL CHEMICAL INDUSTRIES

PLC

Suneel Yeshwant Dike, Anlmugaswamy Ramiah, Uimed DattattY Hajarlis.

CALLINAN LAWRIE, 711 High Street, Kew, 3101, Victoria, Australia TREATMENT OF FABRICS The following statement is a full description of this invention, including the best method of performing it known to me-- CPVV 50525 Treatment of Fabrics This invention relates to a method of imparting wrinkle and/or crease andlor shrink resistance and/or Ssmooth drying properties to fabrics made from cellulosic fibres or yarns or blends containing cellulosic fibres or yams. More particularly it relates to such a method of treatment which does not involve the use of formaldehyde or formaldehyde derivatives or phosphorus containing compounds.

Many commercial processes for imparting wrinkle, crease and/or shrink resistance and/or smooth drying properties to cellulosic fabrics, particularly cotton textiles, are known. The treated fabrics and garments made from them retain their dimensions and smooth appearance in use and also during machine wash and tumble dry processes.

Commercially, such properties can be imparted to cellulosic fabrics by a finishing treatment with resinous compositions. The most commonly used resins for such finishing are based on formaldehyde derivatives such as formaldehyde-urea or substituted urea addition products such as DMEU and DMDHEU. Such resins are believed to function by promoting crosslinking of the cellulose in the fabric thereby imparting the desired properties. In recent years, efforts have been made to develop crosslinking agents which do not include formaldehyde or its derivatives to remove the possible evolution of formaldehyde during manufacture, storage and/or use of cellulose, particularly cotton fabrics, treated with formaldehyde addition products.

Non-formaldehyde crosslinking agents which have been suggested previously include polycarboxylic acids as disclosed by Gaghiardi and Shipee, American Dyestuff Reporter 52, 300 (1963). Rowland et al., Textile Research Journal 37, 393 (1967), disclosed the use of partially neutralized polycarboxylic acids with base prior to the application to the fabric in a pad, dry and heat cure treatment, elaborated US Patent 3526048. Canadian Patent No 2097483 describes rapid esterification and crosslinking of fibrous cellulose in textile form using boric acid or derivatives as crosslinking catalyst.

Welch et al. in US Patents 4975209, 4820307, 4936865 and 5221285 disclose the use of alkali metal salts of phosphorus containing acids, particularly sodium hypophosphite as crosslinking esterification catalysts in the treatment of cellulosic materials. The use of sodium hypophosphite has several disadvantages: it is expensive, relatively high levels are needed in practice and it tends to cause shade changes in fabrics dyed with sulphur dyes or certain reactive dyes. In addition, phosphorus 35 containing effluents can promote algal growth and/or eutrophication of downstream water bodies r such as streams and lakes.

i CPW 50525 S-2- The present invention is based on the discovery that certain sulphur containing acids, particularly sulphonic and/or sulfinic acids, and their alkali metal salts at lower concentration show accelerating effect on esterification and crosslinking of cellulose by polycarboxylic acids. The use of such catalysts can enable the provision of a treatment method that uses neither formaldehyde derivatives I 5 or phosphorus compounds, but can give adequately rapid esterification and crosslinking of cellulosic in fibres to provide effective wrinkle, crease or shrink resistance or smooth drying properties to materials made from such cellulosic fibres. Thus, in this invention fibrous cellulosic material is treated with a polycarboxylic acid in the presence of a sulphonic and/or sulfinic acid curing catalyst at elevated temperature. The process can be carried out by impregnating the material with a solution containing the polycarboxylic acid and the curing catalyst followed by heat treatment to produce esterification and crosslinking of the cellulose with the polycarboxylic acid.

The present invention accordingly provides, a method of treating fibrous cellulosic textile material which comprises: a applying to the cellulosic textile material an aqueous solution including at least one polycarboxylic acid as a crosslinking agent for the cellulose and an organic or inorganic sulphonic or sulfinic acids or a salt as an esterification catalyst, b drying the textile material fabric and heating it to promote crosslinking esterification of the polycarboxylic acid and the cellulose of the cellulosic textile material.

.o S. In referring to the material as being "cellulosic", we mean that the major part of the fibre forming components of the material is cellulose. Thus, the term includes purely cellulosic materials such as cotton and cellulose-rich blends particularly cellulose-rich polyester blends, such as polycotton materials. Typically, the material contains from 30 to 100% of cellulosic fibres. Typical cellulosic 25 fibre materials which can be included in fabrics treated according to this inventions include cotton.

flax, rayon, jute, hemp and ramie. It can also be a synthetic cellulosic fibre material such as rayon, Sparticularly viscose rayon or solvent derived rayon commonly called lyocell fibre. The cellulosic material can be a blend of fibres of cellulosic materials with non-cellulosic materials and in particular includes blends of cellulosic fibres, particularly cotton, with polyester, particularly polyethylene terephthalate polymer or related copolymers. The textile can be a woven (including knitted) or non-woven textile, but as crease resistance is particularly important in clothing, the textile will usually be a clothing textile material.

The term "formaldehyde free" means that the process does not release formaldehyde during the treatment of the fabric with the resin or luring subsequent manufacture of garments or their-use including washing and wearing. The term "wrinkle or crease resistance" means that a treated fabric is less likely to be wrinkled or creased after being worn or after a laundering operation than it would if it had not been so treated.

CPW 50525 -3- The invention uses polycarboxylic acids as cellulose crosslinking agents to improve the wrinkle resistance, shrinkage resistance and smooth drying properties of cellulosic fibre containing textile without the use of formaldehyde or agents that release formaldehyde. Some such polycarboxylic acids are known from the literature. Suitable polycarboxylic acids for use in the method of this invention include aliphatic, including open chain and alicyclic, polycarboxylic acids, and aromatic polycarboxylic acids. Desirably the polycarboxylic acid includes at least 3, particularly at least 4 and often more carboxylic acid groups per molecule.

Particularly suitable aliphatic polycarboxylic acids include acids in which at least two carboxylic acid groups are separated by 2 or 3, more usually 2, carbon atoms and desirably where the polycarboxylic acid includes a plurality of such arranged pairs of carboxylic acid groups. Where such an aliphatic acid includes an ethylenic double bond, it is very desirable that it is positioned a,p- to a carboxylic acid group; such an aliphatic acid may include a hydroxyl group on a carbon atom also 15 carrying a carboxylic acid group; and further the aliphatic chain or ring may include one or more oxygen and/or sulph ir atoms. Suitable aromatic acids include those where at least two carboxylic acid groups are aL., ed to adjacent aromatic ring carbon atoms.

Examples of suitable aliphatic polycarboxylic acids include maleic acid, methylmaleic (citraconic) acid, citric acid, itaconic acid, 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid (commonly known as BTCA), all cis-1,2,3,4-cyclopentaneteracarboxylic acid, oxydisuccinic acid, thiodisuccinic acid; oligo- andlor poly-maleic acid and/or anhydride (as described in GB 2295404 A and WO 96/26314 A and abbreviated "OMA") and suitable aromatic polycarboxylic acids include benzene hexacarboxylic acid and trimellitic acid.

The amount of crosslinking agent used will typically be from 1 to 10%, particularly from about 2 to o. about by weight based on the dry fabric weight. The particular concentration of crosslinking agent used in the treating solution will depend upon the degree of cross linking desired, the proportion of cellulosic fibres in fabric being treated and the solubility of the crosslinking agent.

Typically, the concentration is from about 1 to 20%, more usually 2 to 10% particularly from 0.5 to 7 and especially about by weight of the solution.

The curing catalysts used in this invention are organic or inorganic sulphonic or sulfinic acids or their salts. Suitable catalysts include inorganic sulphonic acids i.e. compounds including the group S3 SO 3 H (or SO 2 OH), particularly halosulphonic and amidosulphonic acids, particularly those of the general formula: XSO 2 OH where X is Cl, F or NH 2 respectively chlorosulphonic and fluorosulphonic acids and amidosulphonic acid (taurine). Suitable organic sulphonic acids typically i CPW 50525 -4have the general formula: RSO 2 OH where R is an organic group, particularly an alkyl or cycloalkyl group, an unsaturated straight or branched chain hydrocarbyl, particularly alkenyl group, or an unsaturated cyclic or arene group.

Particularly active and effective curing catalysts of this invention include the alkane sulphonic acids and their alkali metal salts e.g. methane, ethane, propane, butane, pentane and hexane sulphonic acids, camphor sulphonic acid, isethionic acid (2-hydroxyethane sulphonic acid), methanedi-sulphonic acid and trifluoromethanesulphonic acid. Other useful curing catalysts include arene and alkyl arene sulphonic acids such as benzene, p-hydroxybenzene, p-toluene and dodecylbenzene sulphonic acids, naphthalene-1- and napthalene-2-sulphonic acids and 1,3-benzene and 2,6-naphthalene disulphonic acids and benzene sulphinic acid.

The sulphonic or sulfinic acid catalyst can be used as the free acid or as a salt, particularly an alkali S. metal, ammonium or alkaline earth metal salt, or a mixture of the free acid and a salt or salt(s). The -o 15 15 salt forming cations are particularly of potassium, sodium, ammonium, magnesium, calcium or a mixture of these cations. It is not clear whether the free acid form or the salt form of the curing catalyst is the more active component of the catalyst. The form present will depend on the acidity of the solution used for the treatment of the textile and the effect of the drying and heating steps. We have found that the textile is advantageously treated using a moderately acidic solution, typically 20 having a pH of from 2 to 6, usually not more than 4.5, more usually from 2.5 to 4 and especially about 3. Under such conditions, the curing catalyst may be present as the neutral free acid, as acid anions or a mixture depending on the acidity of the catalyst. Generally sulphonic acids are strong enough acids that they will be present as the free acid (often largely dissociated) in aqueous solution at pH about 3.

i. The amount of catalyst used will typically be from 10 to 200%, more usually 25 to 150%, desirably .to 120%, by weight of the polycarboxylic acid crosslinking agent. Expressed as a percentage based on the (dry weight of the) textile being treated, the amount will typically be from 1 to 30%, more usually from 2 to 20%, particularly 2.5 to 10% by weight. The concentration used in the treatment solution is typically from 0.1 to 20%, more usually from 0.2 to 10%. particularly from 0.5 to by weight of the solution.

The treatment is typically carried out by first impregnating the cellulosic or cellulosic containing textile materials with an aqueous treating solution containing the crosslinking agent and the curing catalyst, removing excess liquid e.g. using wringers, with these steps being repeated, if necessary, to obtain the desired liquid pick up. The material is then dried to remove the solvent and then cured, 7 e.g. in an oven, typically at about 150 to 240 0 C, usually from 160 to 200°C for a time of from seconds to 30 minutes, usually 1 to 5 minutes to promote the esterification and crosslinking of the CPW 50525 cellulose by the polycarboxylic acid. Typically the pick up of treatment solution is from 30 to 120%, more usually from 50 to 100%, particularly about 80% of the dry weight of the untreated textile.

We have confirmed the presence of cellulose ester carbonyl groups in material treated according to the invention by FT-IR (Fourier transform infra red) spectroscopy. The absorption band of the carbonyls of cellulose esters in infra red spectra has been reported and in the range of 1720 to 1750 cm 1 (Zhbankov, "Infrared spectra of cellulose and its derivatives", Consultant Bureau, New York, 1968, pp 315-316). Our observations show an absorption peak at about 1720 to 1735 cm-' The treatment solution containing the crosslinking agent and the curing catalyst forms part of the invention which accordingly specifically includes an aqueous solution of at least in one polycarboxylic acid cellulose crosslinking agent, particularly at a concentration of from 1 to 20% by weight of the solution, and at least one organic or inorganic sulphonic or sulfinic acids or a salt as an esterification catalyst, particularly at a concentration of from 0.2 to 10% by weight of the solution.

SThe invention further includes cloth treated by the method of the invention and in particular, a cellulosic textile material, which may be woven (including knitted) or non-woven, which carries residues of at least in one polycarboxylic acid cellulose crosslinking agent esterified to hydroxylic sites in the cellulose and residues of at least one organic or inorganic sulphonic or sulfinic acids or a salt esterification catalyst.

In these aspects of the invention particularly desirable features are as described for the method of the invention.

CPW 50525 -6- The following Examples illustrate the invention. All parts and percentage are by weight unless otherwise stated.

Materials BTCA 1,2,3,4-butanetetracarboxylic acid OMAi oligo-maleic acid made using benzoyl peroxide as the polymerisation initiator OMAii oligo-maleic acid made using hydrogen peroxide/acetic anhydride as the polymerisation initiator MSA methane sulphonic acid Surf Commercial proprietary domestic detergent ex Hindustan lever Test Methods Wrinkle recovery angles (WRA) were determined by ATCC Test Method 66-1990; Wrinkle recovery of fabrics: Recovery angle method. The wrinkle resistance of woven textiles is represented by the wrinkle recovery angles; the greater the WRA the greater the wrinkle resistance of the fabric.

Results are reported in degrees.

eses Example 1 20 This Example illustrates the use of MSA (Examples la, 1b and 1c) as a curing catalyst for the durable press finishing of cotton fabric using BTCA.

t Cotton cloth test pieces (10 inches square; ca. 25x25 cm;) were thoroughly wetted by immersion in a 0 treatment bath containing an aqueous solution (80 ml) of BTCA (5 g; 6.25%wlv) and MSA (concentration given in Table 1) as curing catalyst at a pH adjusted to 3. The wetted cloth was passed between the rolls of a wringer and the process repeated twice to give an overall pick up I 80% by weight of the dry cloth. The test pieces were stretched on a rack and dried in an air forced draft oven at 85 0 C for 5 minutes. The dried test pieces were then treated in an air draft oven at the temperatures and for the times shown in Table 1 below, in which amounts of BTCA and MSA are expressed as weight based on dry fabric weight. The treated specimens were rinsed for minutes with 1% Surf solution, rinsed with water and air dried and the WRA's) were measured. The WRA results are included in Table 1 below.

Table 1 Ex BTCA MSA Curing Conditions No concn. concn. Temp.(C) Tme (m WRA la 6.25 6.25 170 2 248 lb 6.25 1.25 180 1.5 268 c 1 6.25 1.25 190 1 269 ~kiaaaRLasla~i-~ii~-~iiirrs~ CPW 50525 -7- Example 2 This Example compares MSA Example 2) and sodium hypophosphite (comparative Example C2) as curing catalysts for durable press finishing of cotton fabric with BTCA. The general procedure of Example 1 was followed using the appropriate catalysts and the results are set out in Table 2 below.

Table 2 Ex BTCA Catalyst Curing Conditions WRA No concn. material concn. Temp.(oC) Time (min) C2 6.25 NaH2PO 7.5 180 1.5 271 2 6.25 MSA 1.5 180 2 268-9 Examole 3 S; 15 This Example compares MSA (Examples 3a, 3b and 3c) and sodium hypophosphite (comparative Example C3) as curing catalysts for durable press finishing of cotton fabric with OMA as the crosslinking agent. Examples 3a and 3b used OMAi and Examples 3c and 3C OMAii. The general procedure of Example 1 was followed using the appropriate catalysts in the treatment bath in the concentrations stated in Table 3 below and the results including WRA data are set out in Table 3 below.

Table 3 Ex Resin Catalyst Curing Conditions 25 No material concn. material concn. Temp.(C) Time (min) 3a OMAi 5 MSA 5 180 2 250 3b OMAi 5 MSA 1 180 2 252 3c OMAii 5 MSA 5 180 2 244 i C3 OMAii 5 NaH2PO2 6 180 1.5 246 Example 3 Cotton cloth specimens were prepared by the general procedure of Example 1 using 5% BTCA as the treatment resin and MSA as the curing catalyst at levels of 5% and 1% by weight on the dry fabric. The specimens were heat treated at 180 0 C for 90 seconds. FT-IR spectroscopic examination of both specimens, with particular attention to the frequency range 1750 to 1720 cm 1 showed absorptions at 1728 cm 1 attributed to the presence of crosslinked ester groups.

7a Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof.

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2217/98SPECI.H.0

Claims (6)

11. A method as claimed in claim 10 wherein the amount of hydroxycarboxylic acid used is from 5 to 20% by weight of the polycarboxylic acid crosslinking agent. I

12. A method as claimed in any one of claims 1 to 11 wherein the heating step is carried out at a temperature of from 150 to 240°C.

13. A method as claimed in claim 13 wherein the temperature is from 160 to 200'C.

14. A method as claimed in any one of claims 1 to 13 wherein the heating step is carried out for a time of from 5 seconds to 30 minutes.

15. A method as claimed in claim 14 wherein the time is from 1 to 5 minutes.

16. A method as claimed in any one of claims 1 to 15 substantially as hereindescribed in any one of the Examples. 17 Textile material whenever treated by the method of any one of claims 1 to 16. DATED this 22nd day of July 1998 IMPERIAL CHEMICAL INDUSTRIES PLC 25 by their Patent Attorneys CALLINAN LAWRIE -j- d 32B52i3S.?i P.