US3377131A - Process for desizing,scouring and bleaching cotton and polyester fabrics - Google Patents

Description

@4 SR ERUSS REFERENCE SEARCH EEJUM FI'P8309 XR 507M131 Apnl 9, 1968 G. CERANA 3,377,131

PROCESS FOR DESIZING, SCOURING AND BLEACHING COTTON AND POLYESTER FABRICS Filed Oct. 15. 1965 ABRIC 1 IMPPE'GNAWNG SOLUTION 2 4-- HEAT 3 nor WATER 4 -.sAruRA TED STEAM 5 -WARM WASH/N6 6 WASHING ATA mooennrzo TEMPERATURE 7 COLD WA sum/6 8 HIGH EFFICIENCY SGUEEZ/NG INVENTOR GIUSEPPE CERA NA awzwg a;

ATTORNEYS United States Patent 3,377,131 PROCESS FOR DESIZING, SCOURING AND BLEACHING COTTON AND POLYESTER FABRICS Giuseppe Cerana, Busto Arsizio, Italy, assiguor to Roberto Cerana S.p.A., Busto Arsizio, Varese, Italy, a company of Italy Filed Oct. 15, 1965, Ser. No. 496,586 Claims priority, application Italy, Dec. 10, 1964, 26,341/ 64, Patent 739,960 3 Claims. (Cl. 8-111) ABSTRACT OF THE DISCLOSURE A process for desizing, scouring and bleaching cotton and polyester fabrics in a continuous operation comprised of the steps of impregnating the fabric with a cold aqueous solution of hydrogen peroxide at a concentration of between 30 to 80 grams per liter, passing the fabric through a chamber filled with saturated steam at atmospheric pressure and at a temperature between 90 and 100 C. for a period of time not exceeding 20 minutes, immersing the fabric in water at about 90 C., steaming the fabric for about 2 to 3 minutes, washing the fabric in water at least 3 separate times each time for a very brief period and at a progressively lower temperature and squeezing the fabric to remove a high percentage of the moisture.

Summary of the invention This invention relates to a bleaching process which. is particularly suitable for pure cotton fabrics or fabrics in which cotton is admixed with other natural, artificial or synthetic fibers.

As is known, the fabrics of cotton, rayon staple, cotton and staple admixtures, cotton and synthetic fiber admix= tures, and admixtures of cotton and polyester fibers, are subjected to a sequence of treatments which are at present carried out in separate steps, such as desizing, scouring and bleaching with a noticeable use of labour, remarkable amounts of materials used in such treatments and with a remarkable first cost for the individual relative plants, and this has a bearing on the cost of the end product. The inventive process according to the invention allows an operative cycle which is continuous in; that it performs all three of the steps cited above (desizing, scouring and bleaching) in a single sequence, that is, With= out intermediate stays or storage, thus cutting the first cost, operating expenses and labour cost within extremely reduced limits.

The process of the invention, moreover, afi'ords another great advantage in that it avoids the evolution of injurious vapours for the workmen and employs conventional materials (i.e. no special material whatever) for the constrnction of the installation since the invention process does not present any corrosion problem.

The process according to the invention is, broadly speaking, characterized in that the operations of the desizing, scouring and bleaching are effected in a continuous manner on the full width of the piece of fabric, without any intermediate stops and in an ambient at atmospheric pressure, with only the help of non-acidic aqueous solutions, heat, hot water and steam.

Before exposing a detailed discussion of the inventive process, it is preferred to set forth in the following, by way of summary, a few of the conventional processes presently used:

(a) Sodium hypochlorite process (NaClO), comprising the steps in a distinct operation sequence of: desizing, scouring in full-width piece, a treatment in an autoclave under superheated steam pressure-bleaching with sodium all 3,377,131 Patented Apr. 9, 1968 hypochlorite, acid antichlor treatment, neutralization of the acid e.g. with alkalies (Na CO (b) Sodium chlorite process (NaClO comprising the following sequence of distinct. steps: desizing, scouring and impregnation with a chlorite solution, rolling up on rotatable drums and evolution of chlorine dioxide in a closed zone which is absolutely gastight, for a prolonged time period and at high temperatures, followed by repeated washings.

(0) Mixed hypochlorite and, hydrogen peroxide process (for example similar to the one adopted by Du Pont de Nemours) comprising the following sequence of distinct operation steps: desizing, scouring (usually in the so-called J-boxes) in rope," bleaching with hypochlorite, in rope, bleaching with hydrogen peroxide, and the like.

The process according to the present invention will now be described more in detail. It comprises the following steps, which, however, according to the invention, are carried out in a continuous way without intermediate stays or delays, without use of pressurized enclosures (the process takes place at virtually atmospheric pressure, and with a remarkable economy of first cost, operating expenses, labour, raw materials, auxiliary devices or apparatus, etc. Moreover, as already pointed'out, by using non acidic substances only, no injurious vapours are evolved, which could damage both humans and plants.

The following disclosure refers to the accompanying drawing which is a flowsheet capable of being modified within the scope of the invention and to be carried out by an installation suitable to the purpose.

l) The impregnation of the fabric, in full width (the fabric could be dry or wet), in the cold, is made with an aqueous solution containing hydrogen peroxide at a concentration of from 30 to gms. per liter, e.g. 40 gms. per liter. For example, a solution available in the market under the registered trade mark ROCESA can be used.

(2) Placement of the fabric, in full width for about 15-20 mins., in an impregnated condition (according to the nature, weight, quality of the fabric to be bleached) and at a temperature comprised between C. and C. This step can be carried out with saturated steam obtained through automatic saturation adjustment devices, and has the purpose of removing the residues of substances used in the spinning and weaving (starch, fecula, lubricants etc.).

(3) Placement of the fabric, in full width, in hot water (about 90 C.), wherein it is immersed so as to activate the bleaching liquor, that is so as to have it acting'on the fabric.

(4) Steaming, in full width, for about 2-3 mins. in steam at 100 C. for making the action of the preceding step completed.

(5) Washing of the fabric for a very short time (about 2-3 sees.) in water at about 80 C.

(6) Washing of the fabric, for a very short time (about 2-3 secs.) in water at about 70 C.

(7) Washing of the fabric in cold water at ambient temperature for about 2-3 seconds.

(8) Squeezing at a high squeezing efficiency, for ex ample up to about 60% of the weight of the fabric and subsequent folding (on a truck) or rolling (on a cloth beam) of the treated fabric.

Attention is again directed to the very important fact that, according to the invention, the desizing, scouring and bleaching operations are carried out all at a time in a continuous run.

In order that the technical advance atforded by the in vention with respect to the conventional processes may become fully apparent, a comparison outline is given below, which reports the average results of the known processes of hypochlorite bleaching (1), chlorite bleach ing (2) and the inventive process (3) as related to the treatment of a conventional cotton fabric.

The article is a Madapolam fabric, 70 pieces of 8,400 meters total length, width 90 cms., grams per square meter 130 approx, 100% cotton.

(1 Man-hours, about 24; workers, 9 men. (2) Man-hours, about 17; workers, 3 men. (3)Man-hours, about 6; workers, 2 men.

The foregoing clearly shows that the process of the invention is higher than those of the most conventional art,

I claim:

1. A process for desizing, scouring and bleaching cotton and polyester fabrics in a single continuous operation comprising impregnating the fabric with a cold aqueous solution of hydrogen peroxide at a concentration of 30 to 80 grams per liter, passing the fabric through a chamber filled with saturated steam at atmospheric pressure and at a temperature between 90 and 100 C. for a period of time not exceeding 20 minutes, immersing the fabric in water at about 90 C., steaming the fabric for about 2 to 3 minutes, washing the fabric in water at least three times at a lower temperature eachtime, and squeezing the fabric whereby all of the foregoing steps are carried out with the fabric at full width.

2. A process, as set forth in claim 1, characterized in that the step of washing the fabric at least three times the first washing takes place with the water at 80 C, for a period of time of about two to three seconds, the second washing takes place with the water at a temperature of about 70 C. for a period of time of about two to three seconds and the third washing takes place in water References Cited UNITED STATES PATENTS 5/1961 Nerney et al 8--111 OTHER REFERENCES Continuous Peroxide Bleaching, Rupp, Dec. 7, 1942, American Dyest-ulf Reporter, pages 638-640.

Present-Day Trends in Bleaching, Easton, Nov, 30, 1959, American Dyestufl Reporter, pages 24- 29,

MURRAY KATZ, Primary Examiner.

MAYER WEINBLATT, Examiner.

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