US2265559A - Dyed regenerated cellulose containing a polyamide - Google Patents

Description

Patented Dec. 9, 1941 DYED REGENERATED CELLULO SE CONTAIN ING A POLYAMIDE William Way Watkins, Bnifalo, N. Y., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 9, 1939,

Serial No. 260,876

2 Claims.

This invention relates to the manufacture of artificial filaments, yarns, fibers, films, caps, bands, sponges, or similar structures having an improved aflinity for dyestuffs. More particularly, the invention relates to the manufacture of such structures from cellulosic or synthetic resinous compositions which have filmor filamentforming properties.

Artificial filaments, fibers, films, and similar structures have been produced by spinning or casting operations. Thus, structures have been produced comprising or consisting of regenerated cellulose, as obtained by the viscose or cuprammonium processes; cellulose derivatives including cellulose esters such as cellulose acetate, formate or propionate and cellulose ethers such as methyl, ethyl or benzyl cellulose, as well as mixed esters, mixed ethers, mixed ether-esters or even mixtures of these; or synthetic resinous materials including polymeric vinyl compounds, such as polyvinyl chloride, polyvinyl acetate, chlorinated polyvinyl chloride, interpolymers of polyvinyl chloride and polyvinyl acetate as well as the polymers of acrylic or methacrylic acid and their esters, such as methyl methaorylate and even interpolymers of methacrylate and vinyl chloride or the like.

Direct dyes possess the property of dyeing cotton, linen, and regenerated cellulose, as well as wool and silk, and form a very important class of coloring materials. Direct dyes, in general, are dischargeable which is an important characteristic and is necessary for the manufacture of an important class of textile fabrics known as print goods. Acid dyes are used almost exclusively for dyeing wool, silk, and other animal fibers and are also extremely valuable.

Regenerated cellulose structures are readily dyed with direct colors. Regenerated cellulose, however, has practically no affinity for acid dyestuffs and when regenerated cellulose fibers are mixed with wool to produce composite threads or yarns or when regenerated cellulose yarns are fabricated with woolen yarns to produce mixed fabrics, the product cannot be dyed to a uniform color with acid dyestuffs. Although the mixed fabric might be fairly uniformly dyed with a direct dye, it is at times desirable and preferable to use acid dyestuffs because of differences in lightfastness, laundry-fastness, etc., between direct dye..- and acid dyestuffs.

Cellulose derivative structures and especially the cellulose esters such as cellulose acetate can only be dyed with expensive special dyestuffs and by means of special, expensive and diflicult'procedures. For the most part, none of the cellulose acetate dyes are satisfactorily dischargeable and, consequently, cellulose acetate fabrics cannot be subjected to discharge printing as are fabrics of wool, cotton, regenerated cellulose rayon or the like. Furthermore, cellulose acetate has no aflinity for either the acid or the direct dyes. It is because of this that cellulose acetate has been used to a considerable extent where crossdyeing effects are desired, but on the other hand when cellulose acetate is mixed with regenerated cellulose, cotton, wool or natural silk and a uniform solid color is desired, it has been necessary to subject the same to several dyeing operations in separate dye baths or to go through a long expensive procedure attended by undesirable changes in the yarn or fabric properties. In the same way, structures prepared from synthetic resinous materials having filmor filamentforming properties have been found to be highly resistant to the action of certain well known dyes. These resinous materials have little or no afiinity for either direct or acid dyes and. consequently, it has been impossible to secure suitable dyeing of film, filaments, yarns and the like prepared therefrom.

In some cases the elevated temperatures necessary for dyeing with such dyes as have been found useful, cause the materials to shrink or deteriorate so that use of such dyes is impractical.

It is, therefore, an object of this invention to' improve the affinity of artificial films, filaments, and the like for dyestufis.

It is another object of this invention to improve the affinity of these artificial structures for direct or acid dyestuffs.

It is another object of this invention to improve the afiinity of regenerated cellulose structures for acid dyestuffs.

It is still another object of this invention to improve the aflinity of cellulose derivative structures, such as cellulose acetate, for direct or acid dyestuffs.

It is still another object of this invention to improve the affinity of synthetic resinousfllmor filament-forming materials for either direct or acid dyestuifs.

Other objects will be apparent from the accompanying description and examples.

Generally speaking, the objects of this invention can be accomplished by adding to the structure-forming composition as the case may be, discrete particles of non-cellulosic, non-proteinous, linear polymeric compounds containing In the polyamides the amide groups form an integral part oi! the main chain of atoms in the polymer. These synthetic linear polyamides may be prepared, for example, by a process of condensation polymerization such as is described in Carothers U. S. Patents Nos. 2,130,948, 2,130,523 and 2,071,253.

It has been found that a large variety of synthetic polyamides can be used to accomplish the objects of this invention depending on the type of filmor filament-forming compositions from which the desired structures are to be produced. Generally speaking, a synthetic polyamide will be chosen which will be insoluble or substantially so in the liquid vehicle used to make up the filrnor filament-forming composition. Ii hus, for example, in the case of a regenerated cellulose structure obtained by the viscose process, the synthetic polyamide chosen will be one which is insoluble in water as well as in the caustic solutions used to make up the viscose, and; the acid baths or the like subsequently used in the regeneration process. In the case of a cellulose acetate structure, however, which is to be prepared by dry spinning or dry casting from a volatile solvent vehicle, the synthetic polyamide chosen may be one which is water-soluble so long as it is insoluble in the solvent or solvent mixture which is chosen as the vehicle for the filmor filament-forming composition. Similarly, in the case of a synthetic resinous structure, such as a filament of an interpolymer of polyvinyl chloride and polyvinyl acetate which can be spun by a dry spinning process, the synthetic polyamide will be chosen as one insoluble in the solvent used to make up the spinning solution.

The following examples illustrate certain typical synthetic linear polyamides which can be used in the practice of this invention. These examples are, of course, to be considered as illustrative and not limitative.

Example I Example II Three mols oi hexamethylene diamine and two mols of adipic acid were dissolved in cresol usin a weight of cresol equal to the weight of the reactant material. The mixture was heated in a nitrogen atmosphere for 6 hours at 200 C.

after which the mixture was poured quickly into a relatively large volume of ethyl acetate. A

flocculent, colorless, solid separated from the mixture which was filtered oil and washed with more ethyl acetate. The synthetic linear polyamide so obtained exhibited and intrinsic viscosity of 0.15. It was soluble in phenol and in formic or acetic acid, although it was substantially insoluble in the usual organic solvents.

Instead of the simple polymeric type illustrated by the above examples, numerous other synthetic polyamides can be used for the practice of this invention. Interpolymers can be used, as, for example, the interpolymer obtained by the co-polymerization of hexamethylene diammonium adipate and decamethylene diammonium sebacate or an esteramide interpolymer: e. g., one derived from a diamine, a glycol, and a dibasic acid. Likewise, polyamides obtainable from the reaction of adipic acid with diethylene triamine or from the reaction of diglycolic acid with diethylene triamine or from the reaction of tartaric acid. with hexamethylene diamine or from the reaction of maleic acid with hexamethylene diamine may be used successfully.

Particularly desirableresults are obtainable by the use of linear polyamides having a sumciently low molecular weight to have an intrinsic viscosity not in excess of 0.6. It has also been found that very desirable results are obtainable by the use of that class of linear polyamides which have a low molecular weight and are non-fiber formmg.

The molecular weight of synthetic linear polyamides may be controlled in a number of ways. If a diamine and a dibasic acid are allowed to react in equivalent amounts, the molecular weight of the resulting polymer may be controlled by adjusting the time of reaction, the temperature of reaction, or, more conveniently, by adjusting the amount of water which is present in the reactionvessel. It has been found that the presence of a small amount of excess water' in the reaction vessel, along with the diamine and dicarboxylic acid, represses the polymerization sufiiciently to give a polymer of the desired mechanical properties. The polymer prepared in this way may be readily ground to suitable particle size, and the incorporation of such polymer in films and filaments will permit the dyeing of the latter with any number of the common silk and wool dyes.

Another and very convenient method of controlling the molecular weight is by the use of an excess of diamine or dicarboxylic acid, or other monofunctional or difunctional acid or introgenous base. Thus, the reaction of 3 mols of diamine and 2 mols of dicarboxylic acid gives a polymer in the desired molecular weight range. The nature of the polymer produced by this method may be quite different from that produced by the use of equimolecular proportions of reactants; they are, however, very suitable for use in accordance with the present invention. Not only issuch a polymer satisfactory in its solubility and grinding characteristics, but the acid dyestuffs are especially substantive thereto. Likewise, basic dyes are very substantive to a polymer prepared using excess dibasic acid. N0 solvent is necessary irr conducting the polymerization but, if desired, the phenols or cresols may advantageously be used; when the reaction is completed, the product may be precipitated by the addition of a non-solvent, such as ethyl e ate and further ground up if n y- While it is preferred that the synthetic polyamide employed shall be insoluble in the liquid vehicle used to disperse or dissolve the filmor filament-forming material, it is possible to-use polyamides which show appreciable solubility. This is particularly true in those cases where a dry spinning or dry casting process is to be employed because here, regardless of the solubility, when the liquid vehicle is removed by the evaporation step in the process, the synthetic polyamide will be left associated-with the filmor filament-forming material. In the case where it is desired to modify a regeneratedcellulose Example III Thirty-six grams of the polyhexamethylene adipamide described in Carothers U. S. Patent No. 2,130,948, together with 60 cc. of water and grams of Monopole Oil were placed in a onequart ball mill and ground for 6 hours. The contents were then washed out of the ball'mill with 257 cc. of water giving a slurry containing about 10% of the synthetic linear polyamide with an average particle size of some 3, to 5 microns.

One hundred seventeen grams of this slurry were then stirred into 1500 grams of viscose using a high speed mixer. The viscosewas then deaerated whereupon it was spun in the usual manner using a conventional acid coagulating bath. The resulting regenerated cellulose yarn was processed in the usual' way including desulfuring, bleaching, and washing operations and then dried.

The finished yarn was dyed by immersing it in a bath maintained at 45 C. and containing 1% of Du Pont Anthraquinone Blue SKY (Color Index 1088), 10% Glaubers salt and 4% acetic acid, the proportions of the ingredients of the dye bath being calculated on the dry weightof the yarn. The temperature of the bath was slowly raised to about 85 C. and held at that temperature for 45 minutes, the yarn beingturned frequently during'the dyeing operation. The yarn was found to" dye quite deeply and uniformly with this acid dye for which unmodified regenerated cellulose has little or no afiinity whatsoever.

Example IV A slurry of the synthetic polyamide described in Example II was prepared and added to viscose in the same way as described in Example III. The modified viscose was spun in the customary way into a saturated ammonium sulfate bath from which bath the coagulated but unregenerated yarn was conducted to a hot glycerin bath (temperature 125 C.) wherein regeneration was efiected. The resulting regenerated cellulose yam was washed, processed, and dried in the usual fashion and when subsequently dyed with an acid dye in the manner described in Example 111, the yarn was found to dye to highly satisfactory depth and uniformity.

. Example V H To a solution consistingof 0.25 gram eta-vinyl chloride-methyl methacrylate interpolymer, 10

cc. of chloroform and 2 cc. of methanol, were.

added 0.05 gram of the interpolymer obtained by era-polymerization of equal parts of hexamethyl -ene diammonium adipate and decamethylene diammonium sebacate. The mixture was poured onto the surface of a heated. glass slide and baked for 10 minutes in an oven 130 C. The thin film of modified synthetic resinous material was stripped from the palte easily.

A dye bath consisting of 2 cc. of, 20% aqueous sodium chloride, cc. of 0.2% aqueous dye solution, and 50 cc. of-distilled water was heated to C. and the resinous film material lmmersed therein for several minutes. After dyeing, the film material was washed with hot and cold distilled water and dried. The film material modified with the synthetic polyamide exhibited marked dye receptivity whereas a similar film, unmodified, gave no indications of dye receptivity. Acid dyes such as Pontacyl Fast Blue 5R Conc. (Color Index 289) and PontacyP' Fast Red A. S. (Color Index 176), while direct dyes such as Pontamine Blue RW (Color Index 512) and the red dye obtained by Example I of U. S. Patent. No. 1,940,683 were used, the dyeing time being 5 minutes for acid dye! and 7 minutes for direct dyes.

Example VF procedure set forth in Example III, using Pentamine Fast Red 8 BL (Color Index 278). The

yarn was found to be quite receptive to this dye for which normal cellulose acetate yarn had no aflinity whatsoever.

In order to efiectively improve the dye afllnity of the structure-forming material, the synthetic polyamide may be added to the spinning or cast:

ing composition in concentrations as high as 30% or even more, based on the weight of the structure-forming material present. In general,

however, it has been found that concentrations ranging from 5% to about 20% depending, of course, on the effectiveness of the specific materials chosen, are suiiicient for most purposes. While it is possible to increase the depth of dyeing by the addition of still larger quantities of the synthetic polyamide, increased depth of dyeing is frequently offset by weakening of the structure so that from the practical standpoint, it is advisable to use no more of the synthetic polyamide than is necessary to obtain the depth of color desired.

Film or filament structures of the type described which have been prepared in accordance with the present invention have been found to have particularly improved afiinity for so-called direct dyes, acid dyes, developed color dyes,- chrome dyes and vat dyes. The aflinity of structures for other dyes will also be im-' proved.

As illustrative examples of the above-mentioned classes of dyes for which the structures of the present invention have a satisfactory affinity may be mentioned:

Direct dyes Name Color index Pontamlne" Blue RW. 512 Pontainine" Sk Blue (iBX 518 "Pontamine Ye low CH. 365 "Pontamine" Green BX 593 Pontamine" Orange R 415 The red dye obtained by Example I of U. 8. Patent Acid dyes Name Color index "PontacyP Wool Blue BL 833 PontacyY' Fast Red AS 1 76 Pontacyl" Violet 04B 98 PontacyP' Fast Blue 5R Conc 289 Pontacyl" Green NV Conc 735 Du Pout Anthraquinone Blue SKY 1088 Du Pont Anthraquinone Blue B 1054 Du Pout Anthraquiuone Rubine R Conc 1091 Developed color dyes (diazo dyes) Pontamine Diazo Black BHSW Conc. (Color 7 Index 401).

The blue trisazo dye disclosed in U. S. Patent Also Developed" dyes having Color Index Nos.

317, 654, and 552.

" Chrome dyes "Pontachrome Blue R (Color Index 179). Du Pont Chromate Brown EB (Color Index Pr 12) Also chrome dyes having Color Index Nos. 216,

40, 299, and 302.

Vat dyes Other dyes Basic dyes such as Methylene Blue (Color Index 922) and Rhodamine B (Color Index 749) may be used. 1

Basic substituted anthraquinone dyestuff commonly used to dye unmodified cellulose acetate rayon, such as the red dye l-methylaminoanthraquinone, the yellow dye l-nitro acridone, the blue dye 1.4.5.B-tetra-amino-anthraquinone, the red-violet dye IA-diamino-anthraquinohe, as well as such dyes as the orange dye 4-nitro- .4'-amino-azobenzene may be used. Likewise,

dyesof the type of l-amino--arylamino anthraquinone-2-sulphonic acid may be useful.

The color index numbers cited in the present specification are all taken from Rowes Colour Index," Society of Dyers and Colorists, first edition, 1924.

It is understood, of course, that the structures provided by this invention may be dyed in accordance with any of the customary procedures accuse employed in the dyeing art for the particular type of dye chosen. 4

In those cases where the film or filament structure comprises a substantially water-insensitive material such as cellulose acetate or a conjoint polymer of vinyl chloride and vinyl acetate or an interpolymer of vinyl chloride and methyl methacrylate, the dyeing process can be expedited by including in the dye bath a small amount of a solvent or swelling agent for the structureforming material. Thus, for example,.a small amount of methyl Cellosolve or acetone added to the aqueous dye bath will facilitate the dyeing of a cellulose acetate structure modified in accordance with the present invention. It is readily understood, of course, that this is not a question of the effectiveness of the dye modifying ingredient, but obviously sincethe cellulose acetate, for example, is water-insensitive and since the dye bath is an aqueous medium, the ability of the dye to enter the film or filament structure is probably of a low degree. The addition of the solvent or swelling agent serves to facilitate the entry of the dye into the structure so that the color can be retained by the dye modifying agent light, washing and other factors tending to affect the color. The materials are definitely non-volatile and, therefore, resist removal by heat as in ironing operations. The synthetic linear polyamides are of relatively high molecular weight so that they are slow to diffuse from the fiber thus offering stability and fastness. I

By means of this invention synthetic filaments and yarns may be made into threads which can be mixed with wool, cotton, regenerated cellulose and the like and satisfactory dye results secured with any desired'class of dye. Fabrics made from cellulose derivative yarns or synthetic resinous yarns may be simply and inexpensively dyed with the desired dyestuif. In artificial structures such assponges, for example, those made from viscose, the invention finds particular application. In such structures, properties of luster. transparency,'etc., are very much subordinate to dye receptivity and this invention offers opportunity for use of a large variety of dyes.

Since it is obvious that many changes and modiflcations can be made in the above-described procedures and products without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited except as set forth in the appended claims.

I claim:

1. Regenerated cellulose films and filaments dyed with an acid dyestufi and containing, as an agent for promoting the afiinity of said films and filaments for said acid dyestuff, 5% to 20% of finely divided discrete particles of a synthetic linear polyamide, taken from the class consisting of amino acid polyamides which, upon prolonged heating with a dilute mineral acid, are hydrolyzed yielding the monomeric amino-acid from which they were derived, and diamine-dibasic acid polyamides which, upon heating with a strong mineral acid, are hydrolyzed to the dibasic acids and diamines from which they were derived, said polyamide having recurring structural units containing amide groups, the structural units having a unit length of at least 7, said films and filaments exhibiting a uniform coloration throughout the body thereof.

2. Regenerated cellulose films and filaments 1U dyed with an acid dyestufi and containing, as an agent for promoting the aifinity of said films and filaments for said dyestufi, 5% to 20% of finely divided discrete particles of a synthetic linear polyamide having an intrinsic viscosity not to ex- 15 tural units having a unit length of at least 7, said films and filaments exhibiting auniform coloration throughout the body thereof.

WILLIAM WAY WATKINS.