US3652200A

US3652200A - Concentrated sulfuric acid-dye solution dyeing

Info

Publication number: US3652200A
Application number: US860436A
Authority: US
Inventors: Kazuo Miyasaka
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-09-23
Filing date: 1969-09-23
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28

Abstract

Various types of fibers, especially fibers which can ordinarily only be dyed with some difficulty, are dyed in a relatively short period of time at a relatively low temperature by using a dye bath in which the dye is dissolved in concentrated sulfuric acid, and in which a buffering compound, such as an alkali salt of a weak acid, is preferably added.

Description

United States Patent Miyasaka 14 1 Mar. 28, 1972 [54] CONCENTRATED SULFURIC ACID-DYE 2,400,720 5/1946 Stauding'er ..8/168.2 SOLUTION DYEING 3,129,053 4/1964 Castle ..s/93 3,154,613 10/1964 Epstein 260/308 Inventor Kaluo Miyasaka, Toklwadia, 3,346,322 10/1967 'Finkenauer ..s/79 Itabashi-ku, Tokyo, Japan 3,391,985 7/1968 Zarbachen.... ..8/54 [22] Filed Sept 23 1969 2,684,812 12/1958 Bossard ..8/l77 AB l [21] APP] NOJ 860,436 OTHER PUBLICATIONS Hindle, Papers of the American Association for Textile [52] U S Cl I 854 Technology, March 1957, pages 18-20 8/38, 8/41 R, 8/41 A, 8/41 B, 8/41 C, 8/41 D, 8/39, Primary Examiner Donald Levy 8/92, 8/82, 8/162 B, 8/ 162 R, 8/168, 8/175, 8/177 Ammey 0bln Fisher & Spivak R, 8/177 AB, 8/178 R, 8/178 E, 117/138.8 D, 117/l38.8 E, 117/138.8 F,117/138.8 N, 117/138.8 [57.] ABSTRACT R, 117/141, 264/143, 264/78 [51] Int. Cl. ..D06p 3/14 Various yp of fibers, p i l y fi er which can ordinarily 53 Field of Search ..8/82, 79; zen/30.8; 264/78 y be y with some difficulty, are y in a relatively short 4 period of time at a relatively low temperature by using a dye [56] References Cited bath in which the dye is dissolved in concentrated sulfuric acid, and in which a buffering compound, such as an alkali salt of a weak acid, is preferably added.

5 Claims, No Drawings CONCENTRATED SULFURIC ACID-DYE SOLUTION DYEING BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to a process for dyeing natural and synthetic fibers and synthetic polymers at a relatively low temperature and at a relatively accelerated speed.

2. Description of Prior Art It is well known that retarding agents can be used in a fiber dyeing solution in order to maintain a more uniformly colored fiber. It is also well known that the dye bath can be heated to accelerate the fiber dyeing process and thereby produce a more deeply colored product. In order to dye a difficultly dyeable synthetic fiber, a superheating process or a thermosol dyeing process should be employed. The difficulty of this type of process, however, is that the heated dye bath frequently causes fiber damage.

In conventional dyeing processes, a fiber is dyed in a hot dye bath for an extended period of time. Accordingly, it is necessary to use a batch type process in dyeing various fibers, and especially in dyeing the difficultly dyeable synthetic fibers. Although using a batch process has the disadvantage that it is difficult to make the color of fiber uniform, nevertheless, since the dyeing process requires a period of at least 30 minutes to one hour, a continuous system is impractical. In order to dye a difficultly dyeable synthetic fiber, the dye should be diffused into the microstructure of fiber and be fixed to it.

Although various types of accelerators and other agents have been studied in order to obtain a more uniformly and deeply colored product, heretofore, no completely satisfactory technique has been developed.

SUMMARY OF THE INVENTION It is an object of this invention to provide a quick dyeing process at a relatively low temperature and at a relatively high speed.

It is another object of this invention to provide a continuous process for dyeing fibers at a relatively low temperature and at a relatively high speed to provide a deep, clear color having excellent fastness to light and to washing.

Other objects of this invention will become apparent as the description of the invention proceeds. These and other objects have now herein been attained by the following process:

A dye which is soluble and non-reactive with sulfuric acid is dissolved in concentrated sulfuric acid. A buffering compound, such as an alkali salt of a weak organic or inorganic acid, is added to the sulfuric acid solution to make a dye bath. An acid-resistant fiber, especially a difficultly dyeable synthetic fiber, is passed through the dye bath at a relatively low temperature and at a relatively high speed, whereby the dye is diffused into the internal microstructure of the fiber. The fiber is then treated with water or an alkali solution in water or an alkali solution bath, so that the dye which has been fused into the fibers internal microstructure is crystallized out and fixed to the internal microstructure. The fiber is then washed and dried, if necessary, steamed, to obtain a clear, deep color, having excellent fastness to both light and wash- DETAILED DESCRIPTION OF THE INVENTION The typical quick dyeing process of this invention consists of the following four steps:

FIRST STEP A dye which is soluble and resistant to sulfuric acid is mixed with concentrated sulfuric acid and is dissolved by heating. After cooling, a buffering compound such as an alkali salt of a weak acid is added to the solution with intense stirring. Surface active agents, retarding agents, or accelerating agents, can also be added to the dye bath, if desired.

SECOND STEP An acid-resistant fiber, and especially a difficultly dyeable synthetic fiber or a plastic material, is passed through the dye bath in 50 to 60 Centigrade, at a relatively high speed. The dye solution is then uniformly squeezed out, so that up to about 50 percent of the dye solution remains. At this point, the dye is diffused into the internal microstructure of the fiber.

THIRD STEP The treated fiber is then contacted with water or an alkali solution, so as to cause an acid-base reaction which generates thermal energy. The dye dissolved in sulfuric acid is precipitated by the reaction and is fixed into the internal microstructure of the fiber by thermal energy. All of the remaining dye in the fiber, which is physically absorbed, is then washed out with water.

FOURTH STEP The washed fiber is dried and heat-treated to fix the dye.

Examples of dyes and pigments which may be used for the dye bath of this invention are as follows:

1 Aromatic Condensation Polycyclic Dyes 1.

This type of dye is usually dissolved in more than 90 percent concentrated sulfuric acid, preferably 95 percent concentrated sulfuric acid, at 7075 C. Ponsol orange RRT(C.I.59,705), Mikethrene Marine Blue G (C.I.7l,200), Indanthrene Dark Blue BT(C.I.59,800), Nihonthrene Brilliant Green GREEN B(C.I.59,825), Heliudone Black .IBB(C.I.62,230), Authra Green B(C.I.69,500), Cibanone Violet R Extra(C.I.60,0l0), Caldeon Brilliant Purple RR Extra(C.l.63,365), Vat Red Brown 2R(C.I.69,0l5) and Algol Scarlet R(C.I.73,030).

2. Anthraquinone Vat Dyes This type of dye is usually dissolved in 90 percent and preferably 95 percent concentrated sulfuric acid at 6065 C. Indanthrene Brown G(C.I.69,015), Caledon Yellow G(C.I.65,425), Flavanthrene R(C.I.70,600), Ponsol Red Violet RRNR(C.I.67,895), Vat Green BB(C.I.58,825), Anthra Red RT(C.I.65,215), Cibanone Yellow GC(C.I.67,300), Algol Brilliant Violet 2B(C.I.60,0l I), Durindone Blue G CD(C.I.78,065), Helindone Yellow .IB(C.I.70,605).

3. Indigoide Vat Dyes This type of dye is usually dissolved in more than percent, and preferably more than percent concentrated sulfuric acid at 55-60 C. Brilliant Indigo BASF(C.I.73,035), Mitsui Brilliant Tsuy Indigo B(C.I.73,040), Ciba Violet 4B(C.I.6l,1003B(C.l.73,360), Algol Violet BBN(C.I.73,370), Thioindigo Scarlet T(C.I.73,635), Helindone Blue 3GN(C.I.73,825), Anthra Scarlet GG(C.I.73,355), Durindone Red 3B(C.l.73,385), Hydron Blue 3b(C.I.53,630).

4. Basic Dyes This type of dye is usually dissolved in more than 40 percent, and preferably more than 60 percent, concentrated sulfuric acid at 6570 C. Methyl Green Crystal(C.I.42,590), Acridine Red 3B(C.I.45,000), Rhoduline Orange N(C.I.50,2l5), Neutral Blue(C.I.50,l50), Methyl Violet R(C.I.42,535), Victoria pure Blue BO(C.I.44,045), Safranine T Extra(C.I.50,240), Thioflavine S(C.I.49,005), Janus Brown R Induline Scarlet (C.I.33,500).

5. Anthraquinone Acidic Dyes and Other Acidic Dyes.

This type of dye is dissolved in more than 40 percent of sulfuric acid. Brilliant Acid Green 6B(C.I.42,l00), Xylene Milling Blue BL(C.I.50,315), Fast Acid-Violet B(C.I.42,571), Rosinduline 2G(C.I.50,l20), Acid Violet 4R(C.I.22,895), Acilan Saphirol SE(C.I.50,120), Alizarine Sky Blue B(C.I.62,105), Supracene Red BBT(C.I.68,200), Sapramine Green FB(C.I.62,5 l5), Carbolan Blue B(C.I.62,075), Anthra Red B(C.I.23,9l0), Supramine Blue R(C.I.l7,055), Fast Light Yellow G(C.I.l8,820), Naphthylamine Black 4B(C.l.20,47016,0l 1), Victoria Fast Violet(C.I. 1 3,455), Amido NaphtholRed 6B(C.I.18,055 Naphthol Dark Green G(C.l.20,495), Light Fast Yellow 3G(C.l.18,96015,7ll).

6. Sulfide Dyes This type of dye is usually dissolved in more than 85 percent, and preferably more than 90 percent, of concentrated sulfuric acid at 6065 C. Pyrogen Brilliant Violet R(C.l.53,700), Sulphur Brilliant Green GG(C.I.53,570), Sulfogene Carbon MCF(C.I.53,195), lmmedial Coriath B Extra(C.l.53,260), Hydron Blue G(C.I.53,640), Katigen Indigo R Extra(C.l.53,440), Thionol Orange RR(C.I.53,050), Eclipse Red Violet(C.I.53,228), Thiogen Black(C.l.53,290), Chionone Sky Blue 6B(C.l.53,450).

7. Organic Pigment This type of pigment is usually dissolved in more than 90 percent and preferably 95 percent, concentrated sulfuric acid at 70-75 C. Heliogen Green B(C.l.74,280), Monostral Fast Blue GS(C.I.74,100), Hansa Yellow R(C.I.12,7l), Vulcan Fast Red B(C.l.2l,l20), Pigment Fast Yellow G(C.I.18,700), Permanent Orange G Extra(C.l.l2,060), Vulcanosine Fast Blue GG(C.I.69,800), Phthalogen-Brilliant Green lFFB(C.l.74,280), Helio Fast Pink RL(C.I.60,745), lrgalite Orange PG(C.I.21,110).

8. Direct Dyes This type of dye is usually dissolved in more than 60 percent of sulfuric acid at 6080 C. Pontamine Fast Yellow WBF(C.l.l9,555), Alizarine Direct Violet EEF(C.I.62,005), l-lelio Fast Blue Bl .(C.l.63,005), Benzopurpurine 10B(C.l.23,50022,570), Pyramine Orange R(C.l.24,900), Catechu Brown B(C.I.35,520), Columbia Black FB(C.I.35,730), Diazo Brilliant Green 3G(C.l.28,2802B(C.l.14,785).

9. Dispersed Dyes This type of dye is usually dissolved in more than 40 percent of sulfuric acid at 6080 C. Celliton Fast Red Violet RN(C.l.1 1,120), Cibacet Red 3B(C.l.60,7l0), Celanthrene Fast Pink 3B(C.l.62,015 Serisol Fast Red 3BL(C.I.61,140), Duranol Brilliant Blue CB(C.I.64,500), Dispersol Fast Orange B(C.I.26,080), Setacyl Scarlet B(C.l.l1,ll0), Artisil Direct Brown H(C.l.l 1,100), SRA Rubine B(C.l.ll,070), Supracet Fast Violet B(C.l.6l,105).

As mentioned above, the dyes are usually dissolved in more than 60 percent concentrated sulfuric acid and preferably more than 80 percent concentrated sulfuric acid. Some types of dyes are insoluble in dilute sulfuric acid or even in concentrated sulfuric acid. In that case, the mixture of dye and sulfuric acid should be heated in order to form the solution. Certain types of dye such as anthraquinoloids can be dissolved in more than 90 percent of sulfuric acid by heating.

Suitable buffer compounds which are useful in the present invention include the alkali salts of organic or inorganic acids, such as sodium carbonate, sodium bicarbonate, sodium borate, sodium acetate, sodium tartarate, sodium lactate and the like. When the solubility of the dye in the dye bath is sufficient, the buffering compound added to the dye bath depends upon the solubility of the dye and the type of fiber or polymer. Where wool, polyamide fiber or other material which is less resistant toward sulfuric acid is dyed, the amount of the buffer compound is increased in order to prevent damage.

Certain buffer compounds, such as sodium citrate or sodium tartarate are especially desirable in that they tend to improve the solubility of the dye in the dye bath. Usually, the solubility of the dye in concentrated sulfuric acid is decreased by adding inorganic alkali compounds, such as sodium carbonate; however, addition of sodium citrate or sodium tartarate or certain other organic compounds, may actually increase the solubility of the dye in the dye bath. The buffering compound generally acts to improve the accessibility of the dye into the internal structure of the polymer or fiber and thereby enhance the diffusion of the dye into the internal structure. Even when nonaqueous dye baths are used, the buffer was observed to enhance diffusion. Usually, an inorganic type of buffer compound is used together with an organic type of buffer compound. The total amount of buffer compound should be insufficient, however, to tie up all of the sulfuric acid, since sufficient acid should be present to prevent premature precipitation of the dye until the fiber is treated with the neutralization bath.

Other additives may also be added to the dye bath, such as aluminum sulfate, copper sulfate, chromium sulfate, aniline, or naphthylamine. Also, nonionic surface active agents may be added, if necessary, such as alkylbenzene sulfate, liquid glue or glycerine. Other conventional additives may also be added, if necessary.

The dyeing process of this invention can be used for color- I ing a wide variety of fibers, films, shaped articles, powders or granules such as polypropylene, polyethylene polyether, polyester, polyacrylics, polyvinylchloride, polyvinylidine chloride, polyurethane, and polyamide fibers, as well as animal fibers, such as wool.

The difficultly dyeable synthetic fibers, such as polypropylene, polyethylene, polyether, polyester, polyacrylics, polyvinylchloride, or polyvinylidine chloride, have no affinity for dyes having sulfonic radicals or other strong hydrophilic radicals, accordingly, water-insoluble dyes should be used. Polyamide fibers are less resistant toward concentrated sulfuric acid and accordingly, a buffer compound such as sodium carbonate, sodium bicarbonate, sodium borate, and alkali salts of organic acids should be added to the dye bath in order to prevent damage. Part of the sulfuric acid is reacted with a buffer compound to produce sodium bisulfate, or sodium sulfate, and weak acids, such as carbonic acid, boric acid, and acetic acid. These components impart a buffering action to prevent fiber damage. Moreover, the weak acid acts to loosen the internal structure of the fiber in order to allow more ready diffusion of the dye into the fiber structure. Wool and other fibers having less resistance toward sulfuric acid, should be treated with a dye bath having'a suitable amount of a buffer compound.

The many advantages of the accelerated dyeing process of this invention can be enumerated as follows:

1. The efficiency of the dyeing process is quite improved, since the desired deep color is obtained by dyeing at rather low temperatures for a relatively short period of time.

2. difiicultly dyeable synthetic fibers which have heretofore only been dyed by thermosol methods, or by high temperature treatments, can be easily dyed by this process.

3. High crystalline synthetic fibers can be dyed by this process to produce deep color effects.

4. Heretofore, only specific dyes were usable for dyeing a difficultly dyeable synthetic fiber. By the present process, however, various types of commercial dyes can be used.

5. Since dyeing time is quite short and dyeing temperature is quite low, the present process does not damage the fibers as frequently occurs by conventional dyeing methods.

The characteristic operations and results of the process of this invention are as follows:

1. Water-insoluble dyes, such as vat dyes, sulfide dyes, or ganic pigments and water-dispersing dyes can be used by dissolving the dye in concentrated sulfuric acid to form the dye bath. It is indispensable to dissolve the dye so that it can be diffused into the microstructure of the fiber. The water-insoluble dyes which has first been completely dissolved can be maintained in stable condition despite changes in temperature or the addition of additives. The presence of sulfuric acid therefore acts to accelerate the diffusion of the dye molecule by swelling the fiber. Sulfuric acid also acts to accelerate the absorption of the dye or pigment and it accelerates the fixing of the dye in the fiber. This latter effect is obtained by the thermal energy formed by the reaction of sulfuric acid with water or alkali solution.

2. Quick dyeing at low temperatures is achieved by using a concentrated dye bath. ln order to quickly diffuse a dye into a fiber, a concentrated dye which is dissolved in the form of a molecule is preferably employed. If the dye bath is formed from a concentrated sulfuric acid, the dyeability of thedye is increased to a very high level. Moreover, if the concentration of the dissolved dye is high, the level of dyeability is even further increased. Accordingly, dyeing at low temperatures becomes possible.

3. Most of the water-soluble dyes are quickly dissolved in concentrated sulfuric acid and the diffusion of dye depends on the concentration of dye in the dye bath.

4. In order to prevent damage caused by concentrated sulfuric acid, and in order to prevent surface dyeing, a strong alkali salt of organic or inorganic weak acid is added to the dye bath. It is generally desirable to use a buffering agent, although use of such agent is not mandatory. Depending upon the particular dye and the particular type of fiber being treated, a buffering agent should be added to prevent rapid dyeing of the fiber surface or swelling and dissolution of the fiber by the sulfuric acid. When the fiber is dyed on its surface rather than in its internal microstructure, its color brightness can be easily reduced. The buffer compound is also desirable in that it accelerates the fusion of the dye into the internal microstructure of the fiber to give a bright color and actual fixing. Where the dye is not fixed to the main structure, its presence can cause fiber melting, shrinking, hardening or yellowing when the fiber is subsequently washed in water or an alkali solution whereby heat is generated by the acid-base reaction.

5. A quick dyeing within as short a period of time as one to one hundred and twenty seconds is possible by the process of this invention.

Conventional dyeing methods have required about one or two hours for dyeing. On the other hand, there are difficultly dyeable fibers which are dyeable only at high temperatures, or by thermosol dyeing. However, by the present process, such difficultly dyeable fibers can be dyed at low temperatures within short periods of time. Moreover, excellent light and wash fastness is rendered by the process of this invention.

Some fibers can be damaged by high temperatures, or by extended dyeing periods, but by the present process, these difficulties can be avoided. Quick dyeing is now possible for the previously difficultly dyeable fibers and is unnecessary to decrease the crystallinity of the fiber in order to render it dyeable as in the prior art. The present process, therefore, is quicker and less costly in terms of labor, heat energy and electrical energy and other costs involved in dyeing a fiber. Furthermore, by the present process, it is now possible to operate continuously rather than batch-wise as in the prior art.

EXAMPLE 1 Process For Dyeing Polypropylene And Polyvinylidenechloride Fiber First Step: 6 parts of phthalocyanine Blue is mixed with 200 parts of 98 percent of sulfuric acid and is completely dissolved by heating at 65 C. After cooling to 50 C., 50 parts of sodium acetate, and 1 part of glycerine are added and dissolved under intense agitation to form the dye bath.

Second Step: 20 parts of polypropylene fiber fabric is passed through the dye bath prepared by the First Step for 2 minutes under stirring, and then is uniformly squeezed.

Third Step: The polypropylene fiber fabric treated by the Second Step is immersed in cool water, whereby the dye finely dispersed and fixed in the fir. The fabric is washed with water and then is passed through 40 times by weight of 2 percent sodium carbonate solution in order to neutralize the sulfuric acid remaining on the fabric. The fabric is then washed and dehydrated.

Fourth Step: The polypropylene fabric treated by the Third Step is dried in a ventilation drier at 60 C., and then is steamheated at 115 C. for 20 minutes, to complete the fixing and coloring. The clear and deep color polypropylene fabric having excellent fastness to light and washing is obtained by said steps. Polyvinylidene chloride fiber fabric is treated by the same process stated in the First, Second Third and Fourth Steps. The same results are obtained when other water-insoluble vat dyes, sulfide dyes or organic pigments are used instead of phthalocyanine Blue.

EXAMPLE 2 Process For Dyeing Polyether, Polyvinylchloride And Polyethylene Fiber First Step: 10 parts of Mikethlene Yellow GCN is mixed with 200 parts of 98 percent concentrated sulfuric acid and is completely dissolved by heating at 50 C. 50 parts of sodium acetate, 1 part of sodium alkyl benzene sulfonate and 2 parts of aluminum sulfate are added and dissolved under severe agitation.

Second Step: parts of polyether fiber fabric is passed through the dye bath prepared by the First Step for seconds under stirring, and then is uniformly squeezed.

Third and Fourth Steps: The same steps stated in Example 1 are employed.

The clear and deep color polyether fabric having excellent fastness to light and washing is obtained by said steps. Each of polyvinyl chloride fiber fabric and polyethylene fiber fabric is treated by the same process stated in the First, Second, Third and Fourth Steps, except eliminating the steaming step. The same results are obtained in each case. Other water-insoluble vat dyes, sulfide dyes or organic pigments may be used instead of Mikethlene Yellow GCN with good results.

EXAMPLE 3 Process For Dyeing Polyester And Polyurethane Fiber First Step: 8 parts of Sulphur Brilliant Green 06 is mixed with 200 parts of 90 percent concentrated sulfuric acid and is completely dissolved by heating at 65 C. After cooling to 55 C., 60 parts of sodium acetate, 10 parts of sodium carbonate, and 1 part of a nonionic surface active agent is added and dissolved under intense agitation.

Second Step: 30 parts of polyester fiber fabric is passed through the dye bath prepared. by the First Step for 1 minute under stirring, and then is uniformly squeezed.

Third and Fourth Steps: The same steps stated in Example 1 are employed.

A clear color polyester fabric having excellent fastness to light and washing, is obtained by said steps. Polyurethane fiber fabric is treated by the same process stated in the First, Second, Third and Fourth Steps. A clear and deep color polyurethane fabric having excellent fastness to light and washing is obtained. Other water-insoluble vat dyes, sulfide dyes or organic pigments may be used instead of Sulphur Brilliant Green GG, with similar results.

EXAMPLE 4 Process For Dyeing Polyacrylic Fiber First Step: 10 parts of Indanthrene Brilliant Orange RK is mixed with 200 parts of percent concentrated sulfuric acid and is completely dissolved by heating at 60 C. 50 parts of sodium acetate, 20 parts of sodium carbonate and 1 part of nonionic surface active agent is added and dissolved under intense stirring, to make the dye bath.

Second Step: 20 parts of polyacrylic fiber fabric is passed through the dye bath for 30 seconds at 60 C. under stirring, and then is uniformly squeezed.

Third and Fourth Steps: The same steps stated in Example 1 are employed.

A clear color polyacrylic fabric having excellent fastness to light and washing is obtained by said steps. Other water-insoluble vat dyes, sulfide dyes or organic pigments may be used instead of the lndanthrene Brilliant Orange RK.

EXAMPLE 5 Process For Dyeing Polyester Fiber First Step: 4 parts of Resoline Red PE is mixed with 200 parts of 60 percent concentrated sulfuric acid and is dissolved by heating. After cooling to 40 C., 50 parts of sodium tartarate, 100 pans of sodium acetate, 30 parts of sodium bicarbonate, 120 parts of sodium carbonate, parts of sodium sulfate and parts of aniline are added and dissolved under severe agitation to make the dye bath.

Second Step: 25 parts of polyester fiber fabric is passed through the dye bath prepared by the First Step, for 1 minute, under stirring, at 75 C., and then is uniformly squeezed.

Third and Fourth Steps: The same steps stated in Example are employed. The clear and deep color polyester fabric having excellent fastness to light and washing is obtained by said steps. Each of polyvinylidene chloride fiber, polypropylene fiber, polyester fiber, polyurethane fiber can be dyed with the same process. When dyeing polyvinyl chloride fiber or polyethylene fiber, the treatment in the dye bath should be for 30 seconds instead of 1 minute, and the steaming in the Fourth Step should be omitted. Other dispersion dyes or anthraquinone milling dyes may be used instead of Resoline Red FB, with similar results.

EXAMPLE 6 Process For Dyeing Various Synthetic Fibers First Step: 3 parts of Methyl Violet Extra is mixed with 200 parts of 80 percent concentrated sulfuric acid, and is completely dissolved by heating to 80 C. 50 partsof sodium acetate, 20 parts of sodium carbonate and 1 part of sodium alkylbenzene sulfonate are gradually added to it under intense agitation to make the dye bath.

Second Step: Where polyvinyl chloride fiber, polyethylene fiber, polyether fiber or polyacrylic fiber is dyed, the dye bath is cooled to 50 C. Where either polyurethane fiber or polyester fiber is dyed, the dye bath is cooled to 65 C. Where polypropylene fiber is dyed, the dye bath is kept at 80 C. 20 parts of each fiber fabric is passed through the dye bath prepared by the First Step for 1 minute under stirring, and is uniformly squeezed. Third and Fourth Steps: The same steps stated in Example 1 are employed, except when dyeing polyvinyl chloride, or polyethylene fiber, steaming in the Fourth Step is omitted. A clear and deep colored fabric having excellent fastness is obtained in each case. Other basic dyes may be used instead of Methyl Violet Extra with similar results.

EXAMPLE 7 Process For Dyeing Various Synthetic Fibers First Step: 8 parts of Direct Brilliant Blue RW is mixed with 200 parts of 80 percent concentrated sulfuric acid, and is completely dissolved by heating at 80 C. parts of sodium acetate and 1 part of nonionic surface active agent is mixed and dissolved under intense agitation to make the dye bath. Second Step: Where polyvinyl chloride fiber, polyurethane fiber, polyether fiber or polyacrylic fiber is dyed, the dye bath is cooled to 80 C. 20 parts of each fiber fabric is passed through the dye bath prepared by the First Step for 1 minute under stirring, and is uniformly squeezed.

Third Step: EAch fiber fabric treated by the Second Step is immersed in the solution consisting of 2 parts of aluminum sulfate and 100 parts of water at 60 C. for 2 minutes, and then is washed with water and dehydrated by squeezing.

Fourth Step: When dyeing polyvinyl chloride fiber or polyethylene fiber, the treated fabric is dried in a ventilation drier. When dyeing other fibers, the treated fabric is dried in a ventilation drier and then steam-heated at 115 C. for 20 minutes. A clear and deep colored fabric having excellent fast ness to light and washing is obtained by said steps in each case. Other direct dyes may be used instead of Direct Brilliant Blue RW with similar results.

EXAMPLE 8 Process For Dyeing Polyamide Fiber With Direct Dye First Step: 10 parts of Direct Orange R is mixed with and uniformly dispersed in 200 parts of concentrated sulfuric acid,

and then the dye is completely dissolved by gradually heating to C. The dye solution is cooled to 60 C. by standing at room temperature, after dissolving. Under severe agitation, 50 parts of sodium acetate, and 120 parts of sodium carbonate are added to the dye solution, and then 0.5 parts of sodium alkyl benzene sulfonate is mixed with it to make the dye bath. Second Step: At 60 C., 40 parts of polyamide fiber fabric is passed through the dye bath prepared by the First Step, for 30-60 seconds, whereby the dye is uniformly adsorbed in the fiber, and the wet polyamide fiber fabric is uniformly squeezed so that up to 50 percent, and preferably up to 35 percent of the dye solution remains. Third Step: The polyamide fiber fabric treated by the process of the Second Step, is passed through a water bath to wash it, and to remove the dye which is physically adsorbed on the fiber, sulfuric acid and other components of dye bath. The dye adsorbed in the 'fiber is thereby stably fixed in the fiber. The treated fabric is passed through 40 times by weight of alkali solution made of parts of water and 1 part of 28 percent of ammonia solution for two minutes to neutralize the sulfuric acid remaining on the fabric. Then, it is washed and dehydrated. Fourth Step: The polyamide fiber fabric treated by the process of the Third Step is dried in a ventilation drier at 60 C., and then is steam-heated at C., for 20 minutes, to completely fix the dye on the fiber and to complete the coloring. The clear orange color polyamide fiber fabric is obtained by the process. Other direct dyes may be used instead of Direct Orange R with similar results.

EXAMPLE 9 First Step: 5 parts of Rhodamine 5G is mixed with and uniformly dispersed in 200 parts of concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 75 C. The dye solution is cooled to 60 C. by standing at room temperature after dissolving. Under intense agitation, 30 partsof sodium acetate, 20 parts of sodium lactate, 75 parts of sodium carbonate, 25 parts of sodium bicarbonate, and 1 part of a nonionic surface active agent, are added to the dye solution, and then 100 parts of water is added to make the dye bath.

Second Step: At 45 C., 40 parts of polyamide fiber fabric is passed through the dye bath prepared by the First Step, for

20-30 seconds, whereby the dye is uniformly adsorbed into the fiber. The wet fabric is then uniformly squeezed so that up to 50 percent, and preferably up to 35 percent of the dye solution remains to prevent color spot.

Third Step: The polyamide fiber fabric treated by the process of the Second Step, is washed with cold water to remove the dye which is physically adsorbed on the fiber, sulfuric acid and other components of the dye bath, so that the dye adsorbed into the fiber is stably fixed in the fiber. The treated fabric is passed through 40 times by weight of alkali solution made of 100 parts of water and 0.3 part of sodium carbonate, for 2 minutes to neutralize the sulfuric acid remaining on the fabric. Then it is washed and dehydrated.

Fourth Step: The same step stated in Example 8 is employed. The clear and deep red color polyamide fiber fabric is obtained by the process. Other basic dyes may be used instead of Rhodamine 5G with similar results.

EXAMPLE 10 Process For Dyeing Polyamide Fiber With Acidic Dye First Step: 5 parts of Fast Red B is mixed with and uniformly dispersed in 200 parts of 80 percent concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 70 C. The dye solution is cooled to 60 C. by standing at room temperature, after dissolving. Under intense agitation, parts of sodium acetate, 200 parts of sodium carbonate, l part of a nonionic surface active agent, are added to form the dye bath.

Second Step: At 50 C., 30 parts of polyamide fiber fabric is passed through the dye bath prepared by the First Step,-for -30 seconds, whereby the dye is uniformly adsorbed into the fiber and then the wet fabric is uniformly squeezed so that up to 50 percent, and preferably up to 35 percent of the'dye solution remains to prevent color spotting.

Third and Fourth Steps: The same steps stated in Example 8 are employed. A bright and deep color polyamide fiber fabric is obtained by the process. Other acidic dyes may be used instead of the Fast Red B with similar results.

EXAMPLE 1 1 Process For Dyeing Polyamide Fiber With Dispersion Dye First Step: 3 parts of Resoline Blue FBL is mixed with 200 parts of 60% concentrated sulfuric acid and is dissolved by heating. After cooling to 60 C., 120 parts of sodium acetate, 30 parts of sodium tartarate, and 150 parts of sodium carbonate are added and dissolved under intense agitation to make the dye bath.

Second Step: 40 parts of polyamide fiber fabric is passed through the dye bath prepared by the First Step for 30 seconds, under constant stirring at 60 C., and then is uniformly squeezed as described in Example 10.

Third and Fourth Steps: The same steps stated in Example 8 are employed.

A bright and deep shade color polyamide fabric having excellent fastness to light and washing is obtained by said steps. Other dispersion dyes may be used instead of Resoline Blue FBL with similar results.

EXAMPLE 12 Process For Dyeing Animal Fiber With Vat Dye First Step: 7 parts of Ponsol Golden Orange 36 is mixed with and uniformly dispersed in 200 parts of 96 percent concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 70 C. The dye solution is cooled to 50 C. by standing at room temperature. Under intense agitation, 50 parts of sodium acetate, parts of sodium carbonate and 0.5 part of nonionic surface active agent are added to it to make the dye bath.

Second Step: 30 parts of wool fabric is passed through the dye bath prepared by the First Step, for 30 seconds, at 60 C., whereby the dye is uniformly adsorbed into the fiber, and is uniformly squeezed so that up to 50 percent of the dye solution remains to prevent color spotting.

Third Step: The wool fabric treated by the process of the Second Step, is washed with cold water to remove the dye which is physically adsorbed on the fiber, sulfuric acid and other components of dye bath, whereby the dye adsorbed into the fiber is solidified and stably fixed in the fiber. The treated fabric is passed through 40 times by weight of alkali solution made of 100 parts of water and 1 part of 28 percent of ammonia solution for 2 minutes at room temperature to neutralize the remaining sulfuric acid and is then washed and dehydrated.

Fourth Step: The wool fabric treated by the process of the Third Step is dried in a ventilation drier, and then is steamheated at 1 15 C. for 20 minutes to fix the dye on the fiber and to complete the coloring. A clear and deep blue colored wool fabric is obtained by the process. Other vat dyes may be used instead of Ponsol Orange 30 with similar results.

EXAMPLE 13 Process For Dyeing Wool With Sulfide Dye First Step: 6 parts of Carbanol Blue LB is mixed with and uniformly dispersed in 200 parts of 90 percent concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 60 C. The dye solution is cooled to 50 C. by standing at room temperature. Under intense agitation, 30 parts of sodium acetate, 20 parts of sodium lactate, and 20 parts of sodium borate are gradually added and 1 part of liquid acetyl-glue is added to form the dye bath.

Second Step: 30 parts of wool fabric is passed through the dye bath prepared by the First Step, for 30-60 minutes, 70 C., and is uniformly squeezed so that up to 50 percent of the dye solution remains to prevent color spotting.

Third and Fourth Steps: The same steps stated in Example 10 are employed. A clear and deep green colored wool fabric is obtained by the process. Other sulfide dyes may be used instead of the Carbanol Blue LB with similar results.

EXAMPLE 14 Process For Dyeing Wool With Acidic Dye First Step: 6 parts of Brilliant Orange RN is mixed with and uniformly dispersed in 200 parts of percent concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 65 C. Under intense agitation, 50 parts of sodium acetate, 30 parts of sodium tartarate and 0.5 part of nonionic surface active agent are gradually added, and dissolved, to form the dye bath.

Second Step: 35 parts of a wool fabric is passed through the dye bath prepared by the First Step for 30 minutes, at 60 C., and is uniformly mangled so that up to 50 percent of the dye solution remains to prevent color spotting.

Third and Fourth Steps: The same steps stated in Example 10 are employed.

A deep, clear orange colored wool fabric is obtained by the process. Other acidic dyes may be used instead of Brilliant Orange RN with similar results.

EXAMPLE 15 Process For Dyeing Wool With Basic Dye First Step: 3 parts of crystal Violet 6B is mixed with and uniformly dispersed in 200 parts of 80 percent concentrated sulfuric Tacid, and then the dye is completely dissolved by gradually heatingto 70 C. After cooling to 50 C. at room temperature, 50 parts of sodium acetate, 20 parts of sodium lactate, 10 parts of sodium bicarbonate and 0.5 parts of nonionic surface active agent are gradually added and dissolved under intense agitation, to make the dye bath.

Second Step: 35 parts of wool fabric is passed through the dye bath prepared by the First Step, for30 minutes, at 60 C., and uniformly squeeced so that up to 50 percent of the dye solution remains to prevent color spotting Third and Fourth Steps: The same steps stated in Example 10 are employed.

A clear and deep orange colored wool fabric is obtained by the process. Other basic dyes may be used instead of Crystal Violet 6B, with similar results.

EXAMPLE 16 Process For Dyeing Wool With Direct Dye First Step: 6 parts of Oxamine Red is mixed with and uniformly dispersed in 200 parts of 80 percent concentrated sulfuric acid, and then the dye is completely dissolved by gradually heating to 70 C. After cooling to 50 C. at room temperature, 50 parts of sodium acetate and 20 parts of sodium carbonate are added and moreover 0.5 part of sodium alkyl benzene sulfonate is added and dissolved under severe agitation to make the dye bath. Second Step: 30 parts of wool fabric is passed through the dye bath prepared by the First Step for 30 minutes, at 60 C., and uniformly squeezed so that up to 50 percent of the dye solution remains to prevent color spotting. Third and Fourth Steps: The same steps stated in Example 10 are employed. A clear and deep red colored wool fabric is obtained by the process. Other direct dyes may be used instead of Oxamine Red, with similar results.

What is claimed is:

l. A process for quick dyeing which comprises:

preparing a dye bath for dissolving into sulfuric acid 60 a dye which is soluble and non-reactive with said acid, passing a fiber or film, through said dye bath whereby the dye is diffused into the internal structure of said fiber or film, contacting said treated substance with water or an alkali solution whereby the dye is solidified and fixed into the internal structure of said fiber or film, and, washing and drying said fiber or film.

2. The process of claim 1, wherein an alkali salt of a weak inorganic or organic acid of more than 40 percent concentration by weight of solution buffering compound is added to the dye bath.

3. The process of claim 1, wherein the dye bath is maintained at a temperature of up to about 70 C.

4. The process of claim 1, wherein sodium citrate or sodium tartarate is added to said dye bath containing the sulfuric acid and the inorganic buffering compound.

5. A process for quick dyeing which comprises preparing a dye bath by dissolving into sulfuric acid of more than 60 percent concentration, a dye which is soluble and non-reactive with said acid, 26

passing a fiber or film through said dye bath whereby the film is diffused into the internal structure of said substance, wherein said dye bath is maintained at a temperature of up to about C., contacting said treated fiber or film with water or an alkali solution so as to generate sufficient thermal energy to fix the dye into the internal structure of the fiber or film, washing and drying said fiber or film.

Claims

2. The process of claim 1, wherein an alkali salt of a weak inorganic or organic acid of more than 40 percent concentration by weight of solution buffering compound is added to the dye bath.
3. The process of claim 1, wherein the dye bath is maintained at a temperature of up to about 70* C.
4. The process of claim 1, wherein sodium citrate or sodium tartarate is added to said dye bath containing the sulfuric acid and the inorganic buffering compound.
5. A process for quick dyeing which comprises preparing a dye bath by dissolving into sulfuric acid of more than 60 percent concentration, a dye which is soluble and non-reactive with said acid, 26 passing a fiber or film through said dye bath whereby the film is diffused into the internal structure of said substance, wherein said dye bath is maintained at a temperature of up to about 70* C., contacting said treated fiber or film with water or an alkali solution so as to generate sufficient thermal energy to fix the dye into the internal structure of the fiber or film, washing and drying said fiber or film.