US2297701A - Process of dyeing animal fibers - Google Patents

Description

Patented Oct. 6, 19 42 A PROCESS OF DYEING ANIMAL FIBERS Gustave Theodore Hug, Penna Grove, N. 1., signer to E. I. du Pont de Nemours' a Com-- pany, Wilmington, Del, a corporation of Delaware \ No Drawing. Application April 11, 1940, Serial No. 329,108 I v Claims. (01. He)

. methods, thematerial may be dyed in a reduced This invention relates to the dyeing of animal ilbers withindigoid and anthraguinone types of vat'colors and more particularly to the pretreatment of wool to increase its aflinity for indigo and other vat dyes.

This invention hasv as an object the dyeing of woolen piece goods continuously with vat dyes. A further object is the dyeing of animal fibers'in the form of piece goods, skeins or raw stock with indigoid and anthraquinone vat dyes. Other and further important objects of this invention will i appear as the description proceeds. J

, These objects are accomplished by the following invention which consists of p'retreating the woolen material by padding it through a solution or suspension of a sulfur-containing vat-reducing agent, for instance a compound selected from the group consisting of formamidine sulflnic acid, hydrosulflte, the aldehyde sulfoxylates, thebisulfltes and the water-soluble sulfides, steaming the padded material, rinsing, and subsequently dye-' ing it in a bath containing a reduced indigoid or anthraquinone vat dye. These vat dyes may be reduced by any of the known methods but a caustic-soda-hydrosulflte reduction is preferred.

Inplace of padding and steaming, the pretreatmerit can be 'efiected by immersing the wool in a bath containing one of the compounds mentioned above and treating at elevated temperatures as more fully explained below. Dyeings of indigoid and anthraquinone vat dyes on wool pretreated by either of these methods are considerably stronger than when the pretreatment is omitted. The concentration of the pretreating agent in the pad liquor is not critical; but the preferred range is about 2 170.3 ounces per gallon. Padding may be carried out at any temperature, although temperatures of 140' to 160" F. insure better penetration of the wool. After padding, the impregnated material is steamed at atmospheric pressure, preferably for 3 minutes, and rinsed.

In the alternative method mentioned above, the wool is treated in the form of piece goods, skeins or raw stock, in a bath containing 3 to 5%, based on the weight of the material, clone of the compounds mentioned above for 5 to 30 minutes at 160 to 212 F. The preferred method is a treatment for minutes at 200 F. While temperatures below 160 F. may be employed, they cannot be considered commercially practical due to the proportionate increase in time necessary to obtain the desired effect.

solution of a' vat dye. Any normal procedure for the dyeing of wool issatisfactory, where precautions are taken to avoid excess alkalinity which has a deleterious eflect'on the wool.

Besides iormamidine sulflnic acid, other. suitablepretreating agents are sodium and zinc hydrosulflte, sodium, zinc and basic zinc formaldehyde sulfoxylate', sodium. Potassium and zinc bisulflte, sodium and potassium sulfide. It will be clear from these examples, and numerous others which -I have tried, that the agents suitable for this invention are compounds of the type generally employed asvat-reducing agents, but characterized further by'containing sulfur in the molecule. However, it should not be inferred that these agents have the function ofassisting merely in the reduction of the vat dye in the value for the continuous dyeing of woolen piece goods with vat colors, for example indigo. Thus, due to the increased aflinity, it is possible by this invention to. obtain deep navy shades on wool by dyeing for only 3 minutes in a bath containing 3 ounces per gallon of reduced indigo, paste,

5 whereas when using conventional methods, it would be necessary to dye for 10 minutes, then oxidize and dye for an additional 10 minutes in a second bath, to obtain a similar depth of shade. Such a procedure obviously would not lend itself 49 to a continuous dyeing process.

' conventional methods. This shorter dyeing time A further advantage is the fact that the increased aflinity of the wool permits the production of light to dark shades with vat colors in a much shorter period of time than when using furthermore reduces the possible deleterious effect of alkalies, necessary for the reduction of vat dyes, on the wool fibers. I

A further advantage is the fact that wool pre- 5 treated as described can be readily dyed with those vat colors which normally have little or no afljinity for wool, for example Ponsol" Blue GD Double Paste (Color Index #1113).

Without limiting my invention to any particu- After pretreating by either one of the described Procedure, the following examples are given subsequent dyeing step, inasmuch as I have found to illustrate my preferred mode of operation. Parts entioned are by weight.

Example 1 W001 felt is padded at 150 F. throu h an aqueous solution containing 2% ounces per gallon of iormamidine sulflnic acid. The time of immersion is approximately 3 seconds (operative range 1 to 10 seconds) and the squeezing rolls are adjusted to permit the material to retain 100% of its weight of moisture. The impregnated material is then run directly into a steamer where it is steamed for 3 minutes (operative range 1 to 5 minutes) at atmospheric pressure and then run through a rinse box containing water of about 80 F. After squeezing to remove excess moisture the steamed and rinsed felt is run through a vat con-' taining 3 ounces per gallon of reduced indigo, 20%

. stronger in shade than if untreated wool is dyed in an indigo vat of the same strength.

Example 2 W001 crepe is pretreated by padding through a solution containing 2% ounces per gallon of sodium formaldehyde sulfoxylate, steaming and rinsing as described in Example 1. After dyeing with indigo 20% paste as described in Example 1,

and oxidized by chemical means. Dyeings on pretreated material are at least 50% stronger than dyeings on untreated crepe.

Example 6 W001 crepe is pretreated with formamidine sulilnic acid as described in Example 1. After steam-,- ing and rinsing the material is dyed as described in Example 5, the color selected in this case being Ponsol Jade Green Double Paste (Color Index #1101) The dyeing is considerably stronger than that obtainable on untreated wool.

Example 7 Wool crepe is pretreated with formamldine sulflnic acid as described in Example 1, and dyed as described in Example 5, the color selected being Sulfanthrene" Blue 23D Paste (Color Index #1184). 7 Pretreated material is dyed very much heavier than untreated wool.

Example 8 Wool crepe is pretreated with formamidine sulfinic acid as described in Example 1 and dyed as described in Example 5, the color selected being "Ponsol" Blue GD Double Paste (Color Index #1113). The dyeing is very much stronger than that obtainable on untreated material. I

much heavier shades are obtained than if the pretreatment is omitted. 7

Example 3 W001 flannel is pretreated by padding through a solution containing 2 ounces per ga'llonot sodium bisulfite, steaming and rinsing, and sub= sequently dyeing with indigo 20% paste as de-' scribed in Example 1. Much heavier shades are obtained than when the pretreatment is omitted.

Example 4 W001 skeins are pretreated by immersing for 15 minutes at 200 F., at a volume of 40:1, in a bath containing 5% formamidine sulfinic acid, based on the weight ofthe material. After draining and rinsing, the skeins are dyed for 10 minutes in a bath containing one ounce per gallon of reduced indigo 20% paste. After oxidizing, the pretreated skeins are much heavier in shade than material not thus pretreated.

Equally satisfactory results are obtained by the substitution of 5% sodium sulfide, based on the weight. of the material, for the formamidine sulfinic acid.

- Example 5 W001 crepe is pretreated by padding through a solution containing 2 ounces per gallon of formamidine sulfinic acid, steaming and rinsing as described in Example 1. It is then passed through a bath, for 2 minutes at 125 F., containing one ounce per gallon of reduced "Ponsol Red BN Double Paste (Color Index #1162). The vet dye was reduced with hydrosulfite and caustic soda, as commonly employed in the dyeing of cotton. To present an undue deleterious: action of the alkali on the wool, however, only oi the normal amount of caustic soda was used for re= duction. After passage through the dye bath, the

- sulfinic acid as described in Example 1.

Till

wool crepe is squeezed to remove excess moisture. 93d

Example 9 W001 crepe is pretreated with fordamidine suliinic acid as described in Example 1 and dyed as described in Example 5, the color selected being "Ponsol" Violet AR Paste (Color Index #1135).

The dyeing is very much stronger than that obtainable on untreated material.

Example 10 Wool crepe is pretreated with sodium form- .aldehyde sulfoxylate as described in Example 2 and dyed as described'in Example 5, the color selected being Ponsol" Blue Green FFB Double Paste (Color Index #1173). The dyeing is very much stronger than if the pretreatment is omitted.

' Example 11 Wool crepe is pretreated with sodium formaldehyde sulfoxylate as described in Example 2 and dyed as described in Example 5, the color selectel in this case being Ponsol Golden Orange RRT Paste (Color Index #1097). The dyeing is very much stronger than is obtainable on untreated material.

Example 12 Wool crepe is pretreated with formamidine After steaming and rinsing, the material is padded at 140 F. through a solutioncontaining 2 ounces per gallonof the leuco ester of "Ponsol Jade Green (Color Index #110l) and one ounce per gallon sodium nitrite, The padded material is then developed at '70 to F. for 3 minutes in a 2% solution of sulfuric acid, rinsed and soaped. Much heavier dyelngs are obtained on pretreated wool crepe than on untreated material.

Equally satisfactory results are obtainable if the leuco ester of the vat dye is applied by dyeing in a heel: or jig'instead of by padding.

It will be understood that my invention is susceptible of wide variation in details, within the skill of those versed with this art, without departing from the spirit of this invention.

I claim:

1. In a process of dyeing wool fiber with vat of the agent in the bath being insuflicient to reduce the wool to a rubber-like condition; heating the impregnated fiber, and then subjecting the same to vat dyeing in a bath containing the chosen vat color, alkaline agents and reducing agents.

2. A process as in claim 1, the heating being efiected simultaneously with the impregnation, by using a hot impregnation bath, at a temperature between 160 and 212 F.

3. A process as in claim 1, the heating being eflected by subjecting the fiber to steam ageing at atmospheric pressure, subsequent to treatment with the impregnation bath.

4. A process of dyeing wool fiber, which comprises pretreating the same in an aqueous bath containing a sulfur-containing vat-reducing agent in quantity not exceeding 3 ounces per gallon, but no added alkali and no coloring matter, and heating the treated fiber; then rinsing the fiber and dyeing the same from an alkaline aqueous bath containing a reduced vat dye of the group consisting of anthraquinone vat dyes and indigoid vat dyes, "the time of dyeing not exceeding 3 minutes; and finally subjecting the dyediiber to an oxidation treatment, to reoxidize the dye on the fiber.

5. A process for the continuous dyeing of wool with indigo, which consists in the impregnation of the wool with an aqueous solution of formamidine sulfinic acid at a concentration of from 2 to 3 ounces per gallon steaming the fiber and rinsing; the time of impregnation not exceeding 10 seconds, and the time of steaming not exceeding 5 minutes, then immersing the wool in an aqueous allgaline bath containing reduced indigo, removing the fiber from the bath and oxidizing the color on the fiber.

GUSTAVE THEODORE HUG.