Durable-Press Finishing of Cellulose-Containing Textiles With Aluminum Chlorhydroxide-Hydrogen Peroxide Catalyst System

1. Field of the Invention

This invention relates to durable-press fabrics. More specifically, it relates to a catalyst system that is useful in the treatment of cellulose-containing textile materials with certain formaldehyde-amide adduct finishing agents to give valuable durable-press properties in the textile product

2. Description of the Prior Art

Synergistic catalyst effects are produced when aluminum chlorhydroxide, hereinafter referred to as Al.sub.2 (OH).sub.5 Cl, is used with certain salts or with certain acids. Stronger catalysis results from the use of a combination of such salts or acids and Al.sub.2 (OH).sub.5 Cl than from the use of either component alone. Reinhardt et al., U.S. Pat. No. 3,909,861, have amply demonstrated the uses of Al.sub.2 (OH).sub.5 Cl with various salts and acids. They have also pointed out that some known latent acidic catalysts, such as Mg(H.sub.2 PO.sub.4).sub.2, and alkaline salts are ineffective in combination with Al.sub.2 (OH).sub.5 Cl. These workers demonstrated a buffering effect with strong acids and an activating effect with weak acids by use of Al.sub.2 (OH).sub.5 Cl. They also demonstrated the effectiveness of Al.sub.2 (OH).sub.5 Cl alone as catalyst in treatments by the conventional pad-dry-cure process at temperatures of 140.degree. to 180.degree. C.

Reinhardt et al., American Dyestuff Reporter 64 (May 1975), discuss Al.sub.2 (OH).sub.5 Cl catalyst systems in the specialized techniques of moist curing and steam curing and show effective curing temperatures of from 100.degree. to 180.degree. C. In pad-dry-cure finishing, Al.sub.2 (OH).sub.5 Cl compares favorably with MgCl.sub.2, ZnCl.sub.2, and Zn(NO.sub.3).sub.2 as a catalyst. These workers, in general, teach away from curing at highly elevated temperatures when mixed catalyst systems containing Al.sub.2 (OH).sub.5 Cl are used.

Very little information is available in the literature concerning H.sub.2 O.sub.2 as a catalyst for the reaction of finishing agents used in treatment of cellulose-containing textiles to obtain wash-wear, wrinkle resistance or durable-press properties. Gagliardi, American Dyestuff Reporter 40 (November 1951) lists H.sub.2 O.sub.2 as one of five types of catalyst for resin finishing of fabric. He suggests that, in aqueous solutions containing free formaldehyde, H.sub.2 O.sub.2 will oxidize the formaldehyde to formic acid which then catalyzes the reaction of the resin with cloth. Gagliardi states that this catalyst has not been exploited commercially; the delayed formation of formic acid from free formaldehyde is one major factor hindering such exploitation. Although Gagliardi mentions H.sub.2 O.sub.2 as a catalyst no data or treatment details are presented. Apparently, very specialized conditions must be employed to obtain effective catalysis.

British Pat. No. 482,254 discloses H.sub.2 O.sub.2 as a catalyst for the condensation product of urea and formaldehyde. Of particular note in the teachings of this patent is the highly restrictive method required to make the process operative. Once fabric has been impregnated with H.sub.2 O.sub.2 and a water-soluble condensation product obtained from formaldehyde and urea, or similar amines or amides, it is necessary to quickly heat the wet, impregnated textile to the critical temperature range of 95.degree.-100.degree. C. This highly selective step is required to achieve further resin condensation in the cloth material.

In all prior work, no catalyst system has been employed that is composed of Al.sub.2 (OH).sub.5 Cl and an oxidizing agent such as H.sub.2 O.sub.2. Those systems with Al.sub.2 (OH).sub.5 Cl and another component all teach away from the conventional curing temperatures employed in the pad-dry-cure process. One skilled in the teachings of the prior art would not anticipate effectiveness of H.sub.2 O.sub.2 as a catalyst in textile finishing unless conversion of free formaldehyde to formic acid is promoted either in the treatment bath or in the impregnated fabric.

This invention provides a catalyst system consisting of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 which is operative at high curing temperatures for very short curing times or at curing temperatures down to 130.degree. C. with longer curing times in treatments of cellulose-containing textiles with formaldehyde-amide adduct finishing agents to produce durable-press products. Short curing times at high temperatures, called flash curing, are employed with the use of selected crosslinking agents and the catalyst system. Among suitable finishing agents are dimethylol dihydroxyethyleneurea and dimethylol methyl carbamate. Treatment is accomplished by padding the fabric with the treatment solution, drying the fabric to remove most of the moisture, then curing the fabric.

It is thus an object of this invention to produce cellulose-containing fabrics with excellent durable-press appearance.

It is a further object to provide an improved catalyst system that is efficient and practical for use in treatments for finishing cellulose-containing textiles with certain formaldehyde-amide adduct agents.

A still further object is to furnish a catalyst system consisting of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 that will provide effective and efficient catalysis on flash curing as well as in conventional pad-dry-cure finishing.

The objects of this invention are achieved by use of the catalyst system based upon Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 in treatments for cellulose-containing textiles with formaldehyde-amide adduct finishing agents. The specific combination of the Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 provides efficient, rapid catalysis in flash cure processing.

We have found that a catalyst system consisting of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 is highly efficient in treatments for producing durable-press fabric but with little apparent formation of formic acid in the process. This is particularly noteworthy as anyone skilled in the art would avoid formation of a strong acid on the fabric at elevated temperatures because of the well-known deleterious effect of the hydrolytic action of strong acids on textile properties. The catalyst system consisting of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 is effective at curing temperatures up to about 200.degree. C. A rapid, high temperature cure, hereinafter referred to as flash curing, can be accomplished at 200.degree. C. in 10 seconds.

The catalyst system of the present invention offers the textile finisher the ability to achieve certain treatments under processing conditions previously found impossible or impractical to employ.

The catalyst system is composed of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2. Concentrations of Al.sub.2 (OH).sub.5 Cl that may be used are from about 2 millimoles to about 10 millimoles for each 100 g. of treatment bath. Expressed alternatively, these concentrations are about from 0.35% to 1.75%, by weight, of the treatment bath. Hydrogen peroxide concentrations employed should be such that the molar ratio of Al.sub.2 (OH).sub.5 Cl to H.sub.2 O.sub.2 is in the range of from about 1:4 to about 1:0.25. The preferred molar ratio of Al.sub.2 (OH).sub.5 Cl to H.sub.2 O.sub.2 is about 1:1; preferred concentrations are about 5 millimoles of each in 100 g. of treatment bath (or about 0.87% Al.sub.2 (OH).sub.5 Cl and 0.17% H.sub.2 O.sub.2, by weight).

Formaldehyde-amide adduct crosslinking agents, selected from the group consisting of dimethylol dihydroxyethyleneurea, dimethylol ethyleneurea, dimethylol alkyl carbamates, dimethylol alkoxyalkyl carbamates, dimethylol hydroxyalkyl carbamates, and the esterified and etherified N-methylol derivatives thereof such as acetoxymethyl alkyl carbamates and methoxymethyl ethleneurea and the like, may be used in concentrations ranging from about 7% to about 20%, by weight, of the treatment bath.

Temperatures to achieve flash curing range from about 175.degree. C. to about 215.degree. C. with the preferred temperature being about 200.degree. C. Times for flash curing may be from about 10 seconds to about 45 seconds, the preferred flash curing conditions are 20 seconds at 200.degree. C. With suitable adjustment of processing time, lower curing temperatures, i.e., in the more conventional range of 120.degree.-175.degree. C., also may be employed. For example, curing at 130.degree. C. for 3 minutes can be effectively employed with the catalyst system of this invention.

The cellulose-containing material may contain 50% or more cellulose and may be in the form of fibers, yarns, or fabrics. Fabric is the most suitable form for treatment to achieve durable-press properties.

The following examples further describe the invention. They are given as illustrations and thus should not be considered as limiting the scope of the invention. In the examples, durable-press (DP) ratings, tumble dried (TD) were determined according to the test procedure described in AATCC 124-1969, III-B.

Aqueous solutions were prepared such that in each 100 g. there were 9 g. of dimethylol dihydroxyethyleneurea, 5 millimoles of Al.sub.2 (OH).sub.5 Cl, and 5 millimoles of H.sub.2 O.sub.2 with:

Sample A--no free formaldehyde (FF) added;

Sample B--with 0.2% FF added;

Sample C--with 0.4% FF added;

Sample D--with 0.6% FF added; and

Sample E--with 0.8% FF added.

A 3.2 oz/sq. yd. cotton printcloth fabric was used for treatments. Samples were impregnated with these solutions and squeezed through pad rolls to achieve approximately 80% (by weight) wet pick-up of the treatment solution. The wet, impregnated samples were pinned on frames, then dried for 7 minutes at 60.degree. C. and cured for 3 minutes at 140.degree. C. Samples were then washed, tumble dried and rated for durable-press (DP) appearance.

Results are given in Table I.

This demonstrates that addition of free formaldehyde to the treatment bath containing H.sub.2 O.sub.2 has no influence on improvement of durable-press appearance.

Aqueous solutions were prepared such that in each 100 g. there were 9 g. of dimethylol dihydroxyethyleneurea and:

Sample F--5 millimoles of Al.sub.2 (OH).sub.5 Cl and 5 millimoles of HCOOH;

Sample G--10 millimoles of Al.sub.2 (OH).sub.5 Cl;

Sample H--5 millimoles of HCOOH; and

Sample I--10 millimoles of HCOOH.

A 3.2 oz/sq. yd. cotton printcloth fabric was used for the treatments. Samples were impregnated with these solutions and squeezed through pad rolls to achieve wet pick-ups of approximately 80% (by weight) of the treatment solution. The wet, impregnated fabrics were pinned on frames then dried for 7 minutes at 60.degree. C. and cured for 3 minutes at 160.degree. C. After curing, samples were washed, dried, and rated as in Example 1.

Results are given in Table II.

No synergistic catalytic effect was obtained by adding HCOOH to Al.sub.2 (OH).sub.5 Cl as seen by comparing DP ratings of Samples F. and G. Further, it is demonstrated that HCOOH is not a satisfactory catalyst in developing suitable DP performance in the treatment of fabric with DMDHEU, see Samples H and I.

The use of the Al.sub.2 (OH).sub.5 Cl/H.sub.2 O.sub.2 catalyst system in finishing cotton fabric by the pad-dry-cure method with dimethylol methyl carbamate is illustrated by the data of Table III. The synergistic interaction of the catalyst components at both the 130.degree. C. and 160.degree. C. curing temperatures should be noted.

The use of Al.sub.2 (OH).sub.5 Cl, Al.sub.2 (OH).sub.5 Cl/H.sub.2 O.sub.2, and H.sub.2 O.sub.2 catalyst systems with dimethylol methyl carbamate in finishing a cotton printcloth and a 50/50 cotton/polyester percale sheeting at various times in flash curing is illustrated in Table IV.

The superior catalytic action afforded through the synergistic effect of the catalyst mixture should be particularly noted.

The use of the Al.sub.2 (OH).sub.5 Cl/H.sub.2 O.sub.2 catalyst system in finishing cotton printcloth and a 50/50 cotton/polyester percale sheeting with dimethylol methyl carbamate by flash curing is illustrated in Table V. Improvement in durable-press appearance is achieved with concentrations of Al.sub.2 (OH).sub.5 Cl and H.sub.2 O.sub.2 as low as 2.5 millimoles of each per 100 g. of treatment bath.

Catalyst systems incorporating the oxidizing agents, K.sub.2 S.sub.2 O.sub.8 or (NH.sub.4).sub.2 S.sub.2 O.sub.8, and Al.sub.2 (OH).sub.5 Cl with dimethylol methyl carbamate in finishing a cotton printcloth resulted in fabric discoloration as seen in Table VI.

This demonstrates that oxidizing agents other than H.sub.2 O.sub.2 are not suitable in flash curing for producing durable-press fabrics without fabric discoloration.