US2251914A - Method of printing textiles - Google Patents

Description

Patented Aug. 12, 1941 METHOD OF PRINTING TEXTILES Norman S. Cassel, Ridgewood, N. J., assignor to lnterchemical Corporation, New York, N. Y., a corporation of Ohio N Drawing. Application August 22, 1939, Serial No. 291,325

3 Claims.

This invention relates to textile printing, and is directed particularly to textile printing pastes and to methods of printing involving the use of different types of printing pastes.

Conventional textile printing is ordinarily done with water solutions of dyestuffs containing water soluble thickening agents in suflicient quantity to retard the spreading of the color on the fabric after printing. The dyestuff is fixed onto the fabric by some chemical process and the binding agent is then washed out of the fabric. The time and expense involved in this after treatment, added to the originally high color cost for light and tub-fast dyes, has been a major problem in textile printing. -An unsolved problem has been the reproduction of very fine designs. Since the pastes spread on the fabric after printing when thin enough to be removed sharply from fine engravings, giving blurred designs, it has been found impossible to use photogravure cylinders or extremely fine mill and dye engravings. Attempts to modify these pastes by addition of wetting agents and emulsification of oils therein have not solved the basic difficulties.

The use as printing pastes of colored lacquers (which, for the purpose of this application are defined as dispersions of color in vehicles consisting of a solution of a plastic or solid filmforming, water-resistant binder such as a cellulose derivative or a resin, in an organic solvent or mixture of solvents) has been attempted in order to overcome the difficulties with prior art pastes, but has not been successful commercially. Relatively few lacquer compositions withstand both dry cleaning and washing; and such compositions as are resistant have been generally unacceptable due to the fact that the fabrics, when printed with these lacquers, develop an undesirable stiff feel (known to the trade as hand) to the necessity for using large amounts of color to obtain deep shades, and to the tendency of colored markings to rub off onto other clothing and leave a mark (known as crocking) A new type of textile printing paste has been suggested, which eliminates the disadvantages of the conventional dye printing paste and avoids the difficulties which have been encountered in the prior art lacquer printing pastes. These new pastes are emulsions in which an outer con tinuous water-immiscible lacquer phase is thickened by an inner aqueous phase which is at least 20 per cent of the total emulsion, by weight. Preferably, the binder of the lacquer is one which is originally soluble in ordinary organic solvents and which can be converted into an insoluble state after printingmost desirably, a readily heat-polymerizable synthetic resin, best exemplified by plasticized urea formaldehyde resin,

The utilization of such pastes permits of the use of cheap pigments and avoids the after treatment necessary with conventional printing pastes. Furthermore, these new pastes separate sharply even from very fine photogravure cylinders, although thickened sufficiently to prevent any spreading on the fabric; this makes possible much finer printing than can be obtained with conventional pastes. The hand imparted to fabrics by these new pastes is very much less than the hand imparted to similar fabrics by ordinary lacquer pastes having the same binder, the amount of color needed to produce deep shades is sharply reduced, and the crocking substantially eliminated.

These pigmented, water-in-lacquer emulsion pastes, while they offer tremendous advantages over conventional dye pastes, are lacking in the one respect that the very brilliant shades obtained with some dyes cannot be obtained with pigments. Attempts have therefore been made, in multicolor printing, to use the two types of printing pastes together. However, the type of paste which is printed first is picked up from the cloth to some extent by the cylinder carrying the other type of paste, and scraped off the cylinder into the main body of the other paste in rather large aggregates. When conventional pastes are dropped into water-in-lacquer emulsion pastes in this fashion, they break up rather readily and become distributed in the emulsion. Some difficulty is encountered when emulsion pastes are dropped into alkaline or neutral conventional pastes, but ordinarily the aggregates of lacquer paste defiocculate rather well. However, when conventional pastes are acid in reaction (as with the type of pastes used to print the diazo fast color salts which are capable of coupling with beta-oxy-naphthoic acid or its derivatives to produce fast dyeings on cotton) the aggregates will not defiocculate, and considerable trouble is encountered, since the aggregates are picked up by the roller, and cause defects in the resultant prints.

I have discovered that hydrophobe lacquerprinting pastescan be used in conjunction with conventional prior art aqueous acid reacting printing pastes by incorporating into the aqueous paste a hydrophobe solvent for the binder of the lacquer paste, together with an agent to emulsify the solvent.

Useful emulsifying agents include sodium lauryl sulfate, mahogany sulfonates, sulfonated castor oil, Turkey red oil and the like; practically any emulsifying agent is satisfactory which will keep the solvent emulsified in the presence of the acid. The amount generally required varies, depending on the particular agent used, but in general amounts of the order of 1% and less are sufficient to keep the solvent emulsified.

The solvent may be any hydrophobe solvent having a solvent action on the lacquer.

quantity required will vary, depending on the size of blotch printed with the hydrophobe paste, and the resultant impurities in the aqueous paste. In general, at least 0.5% is required to produce results. For most printing, amounts over are unnecessary, since the aqueous printing paste is replenished as the cloth is printed. More may be used without harm, and additional solvents can be added from time to time as desired.

An aqueous paste useful in the practice of my invention is the following:

Example 1 Parts by weight Fast Blue Salt B (Schultz7th edition 490) 40 and 50%,acetic acid 40 are dissolved in Water at about C 420 and the solution is stirred into Neutral starch tragacanth thickener 500 To 1,000 parts of this conventional paste are added 40 parts by weight of a mixture of- Parts Sulfonated castorfoil White pine oil 40 Solvesso #3 (hydrogenated petroleum sol- Water 490 Tragacanth solution gum tragacanth:

1000 water) 400 This paste may beused inmulti-color textile printing in conjunction with the following paste:

Example 2 Parts by weight Hydrophobe urea formaldehyde resin solution (50% resin, 30% butanol, 20% xylol) Alkyd resin (mixed ester of glycerol, phthalic anhydride and soya bean oil fatty acid corresponding to 25% glycerol phthalate and soya bean oil), Turpentine substitute (petroleum hydrocarbon) are stirred together to form the lacquer phase. Copper phthalocyanine blue pulp (20% pigment, water) are let down with Water and stirred into the lacquer phase in a turbo mixer at a relatively high speed, and the mix is then passed through a colloid mill or homogenizer.

The hydrophobe lacquer, carried by the cloth, offsets onto the aqueous cylinder, but when aga paste of printing The gregates of hydrophobe paste drop into the main body of the aqueous paste, they are rapidly deflocculated by the action of the solvent, so that the particles become sufliciently fine to produce a uniform, and very slight, effect on the aqueous paste.

The paste of Example 1 may be used with any other lacquers which are miscible with the solvents of the paste, including ordinary lacquer printing pastes containing no water. When cellulose ester lacquers are used, the solvents dispersed in the aqueous paste must, of course, be changed to solvents miscible with the cellulose ester lacquers, and should contain some solvent for the cellulose ester to prevent precipitation on mixing. It is obvious that subtantially any type of hydrophobe lacquer paste may be used, provided the solvent emulsified in the conventional paste is properly chosen.

Other changes in the constitution of the various pastes or in order of application may be made without departing from the spirit of my invention, which is set forth in the claims.

I'claim:

1. The method of printing on textiles which comprises printing one or more colors with a hydrophobe lacquer printing paste, and thereafter printing one or more colors with an aqueous printing paste comprising a dyestufi in an aqueous acid-reacting medium, a water-soluble thickener in suflicient'quantity to produce a paste of printing consistency, and an organic waterimmiscible solvent for the binder of the lacquer dispersed therein by means of an emulsifying agent active in the acid solution.

2. The method of printing on textiles which comprises printing one or more colors with a hydrophobe lacquer printing paste containing water dispersed therein as the interior phase of awater-in-lacquer emulsion, and thereafter printing one or more colors with-an aqueous printing paste comprising a dyestufi in an aqueous acid-reacting medium, a water-soluble thickener in suflicient quantity to produce a paste of printing consistency, and an organic waterimmiscible solvent for the binder of the lacquer dispersed therein by means of an emulsifying agent active in the acid solution.

3. The method of printing on textiles which comprises printing one or more colors with a pigmented hydrophobe lacquer printing paste, and thereafter printing one or more colors with an aqueous printing paste comprising a dyestufi in an aqueous acid-reacting medium, a watersoluble thickener in suflicient quantity to produce consistency, and an organic water-immiscible solvent for the binderof the lacquer dispersed therein by means of an emulsifying agent active in the acid solution.