Method for coloring fibrous material composed of phenolic resins

Abstract

A method for coloring fibers or fibrous structures composed of phenolic resins, which comprises coloring the fibers or fibrous structures using a dye liquor which contains as a dyeing assistant at least one amide compound of the general formula ##EQU1## wherein R, R' and R" are the same or different and each represent a hydrogen atom, an alkyl group, a phenyl group, a benzyl group or a phenetyl group, but R, R' and R" do not represent hydrogen atoms at the same time.

Description

This invention relates to a method for coloring fibers or fibrous structures prepared from phenolic resins. More specifically, this invention relates to a method for uniformly coloring phenolic fibers or their structures in deep colors with fastness characteristics.

As is well known, fibers composed of phenolic resins (to be referred to simply as phenolic fibers) have poor affinity with dyes and extremely low dyeability for a variety of reasons such as their compact fibrous structure, the lack of dye-affinitive groups, or their high negative surface potential. It is very difficult therefore to color phenolic fibers uniformly in deep fast colors.

Other fibers having a compact fibrous structure and no dye-affinitive groups, such as polyester fibers or polypropylene fibers, are colored at a temperature as high as 110.degree. to 130.degree.C. using dyes having a small molecular volume, or using a dye liquor containing a carrier material (swelling agent) such as ortho-phenylphenol, chlorobenzene, a salicylic acid ester or a benzoic acid ester in order to give satisfactory dyeings.

In contrast, the phenolic fibers can scarcely be colored substantially even at 110.degree. to 130.degree.C. using a carrier material such as those mentioned above, and it has been difficult to provide colored phenolic fibers which are useful for practical applications.

Certain kinds for such difficultly-dyeable synthetic fibers have previously been colored, for example, by a method wherein a substance having dye-affinitive groups, such as a polymer having a free amino group, is incorporated in a spinning solution, and fibers obtained by spinning this solution are dyed by conventional methods, a method wherein a pigment is incorporated in a spinning solution beforehand, and the spinning solution is spun to form colored fibers, or a method wherein a pigment is fixed to the surface of the fibers by a binder to color the fibers.

However, when such methods are used for coloring phenolic fibers, the results are poor. For example, when a reagent (for example, hydrazine) having a functional group capable of being bound to a dye or an organic or inorganic pigment is added to a molten prepolymer of the phenol type, and the mixture is spun and then cured, the tenacity of the phenolic fibers after curing is markedly reduced, or the desirable non-combustibility of phenolic fibers is impaired. On the other hand, when the phenolic fibers are colored by fixing a pigment to their surfaces using a binder, the resulting colored fibers prove infeasible because of poor fastness characteristics or harsh finish. In addition, many binders that can be applied for this purpose impart combustibility to the phenolic fibers, and thus hamper their most desirable property (i.e., non-combustibility).

Accordingly, the conventional methods for coloring synthetic fibers have not proved satisfactory for dyeing phenolic fibers, and the development of a dyeing method for the phenolic fibers which can gain commercial acceptance with good results has been strongly desired.

A primary object of this invention is to provide an improved method for coloring fibers composed of phenolic resins and structures formed from these fibers (to be referred to generically as phenolic fibrous materials).

A secondary object of this invention is to provide a method for uniformly coloring phenolic fibrous material in deep fast colors.

Another object of this invention is to provide a method for coloring phenolic fibrous materials that can be utilized industrially.

Other objects and advantages of this invention will become apparent from the following description.

According to this invention, there is provided a method for coloring fibers or fibrous structures composed of phenolic resins, which comprises dyeing the fibers or fibrous structures using a dye bath containing as a dyeing assistant at least one amide compound expressed by the following general formula ##EQU2## wherein R, R' and R" are the same or different and each represent a hydrogen atom, an alkyl group, a phenyl group, a benzyl group or a phenetyl group, but R, R' and R" do not represent hydrogen atoms at the same time. The term "coloring(or dyeing)", used in the present specification and claims, denotes coloring in a broad sense, and therefore, includes (a) the dip dyeing whereby a fibrous material is dyed as dipped in a dye solution, (b) the pad dyeing whereby a dye solution is padded on a fibrous material, and then the fibrous material is heated, and (c) the printing whereby a printing paste is applied to a fibrous material, and the material is then heated to color the printed portions.

Accordingly, the dye liquor used in accordance with the process of this invention may be in the form of a solution containing a dye (especially in the case of dip dyeing) or a paste containing a dye (pad dyeing and printing).

A typical composition of such a dye liquor is illustrated as follows although the invention is not limited thereto.

______________________________________ Composition of the dye liquor for dip dyeing and pad dyeing ______________________________________ Dye in an amount corresponding to about 0.01 to about 30% by weight of the material to be dyed Amide compound of formula (I) above in the amount to be indicated below Viscosity Absent or present in a small regulator amount Water the remainder Composition of the dye liquor for printing ______________________________________ Dye in an amount corresponding to about 5 to about 50% of the total weight of the dye liquor Paste* in an amount corresponding to about 0.1 to about 10% of the total weight of the dye liquor Amide compound of formula (I) above in the amount to be indicated below Water remainder ______________________________________ *Examples of the printing paste include sodium alginate, tragacanth rubber, starch hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, carboxy methyl starch, gelatin, dextrin, British gum, polyviny alcohol, kerosene, and 1,1,1-trichloroethane.

The term "fibers composed of phenolic resins (phenolic fibers)", as referred to in the present specification and claims, denotes uncured fibers formed by melt spinning, or wet spinning, etc. of a prepolymer of the novolak or resol type prepared from a phenol (e.g., phenol, cresol, xylenol, ethylphenol, phenylphenol, amylphenol, bisphenol A, or resorcinol) and an aldehyde (Formaldehyde, acetaldehyde, para-formaldehyde, hexamethylene tetramine, furfural, glutaraldehyde, or glyoxal), or the cured products thereof obtained by curing such uncured fibers with a curing agent such as an aldehyde in the presence of an alkaline or acidic catalyst.

Since the phenolic fibers can be produced by any known method, we will not describe it here.

The phenolic fibers to be dyed by the method of this invention may be composed of a phenolic resin alone, or a blend of a major proportion of the phenolic resin with a minor proportion (generally, 1-40% by weight) of another fiber-forming polymer. In order, however, not to impair the incombustibility of the phenolic resin, the amount of the fiber-forming polymer should be as small as possible, preferably up to 30 % by weight, when the blend is used, or the phenolic fibers should be composed solely of the phenolic resin.

Specific examples of the fiber-forming polymer that can be used include polyamide resins such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 611, nylon 612, and blends of two or more of these with each other; polyester resins such as polyethylene terephthalate, polyesters derived from the same constituent elements as polyethylene terephthalate with part of ethylene glycol replaced by other known glycols, polyesters derived from the same constituent elements as polyethylene terephthalate with the terephthalic acid replaced by ortho- or metaphthalic acids, other known aliphatic dicarboxylic acids or blends of two or more of these with each other; polyester ethers such as polyethylene hydroxybenzoate, and polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, or blends of two or more of these with each other.

The term "fibrous structures composed of phenolic resins", used in the present specification and claims, denotes a fibrous product such as a web, yarn, woven fabric, knitted fabric, non-woven fabric, carpet, batt or laminated cloth composed of the phenolic fibers alone or a composite of the phenolic fibers and other natural, semi-synthetic or synthetic fibers.

Most of the dyes that are usually used in the dyeing of natural, semi-synthetic or synthetic fibrous materials can be used in accordance with the method of this invention for dyeing the phenolic fibrous materials. For example, there are used, vat dyes, azoic dyes, cationic dyes, disperse dyes, metal-containing dyes, acid dyes, direct dyes, reactive dyes, and chrome dyes. Of these, the azoic dyes, cationic dyes, disperse dyes and vat dyes have good dyeability with regard to the phenolic fibers, and can be conveniently used in the present invention. Typical examples of these dyes are as follows:

1. Cationic dyes

Cationic dyes of the azo, diphenylmethane, triphenylmethane, xanthene, acridine, quinoline, methine, thiazole, azine, thiazine, and oxazine types. Specific examples are Sumiacryl Orange G (C.I. Basic Orange 21), Sumiacryl Brilliant Red BB, Sumiacryl Red 6B (C.I. Basic Violet 7), Sumiacryl Brown 3G (C.I. Basic Orange 30), Sumiacryl Blue GG (C. I. Basic Blue 22), Diacryl Brilliant Pink R (C.I. Basic Red 35), Diacryl Blue 2RL (C.I. Basic Blue 59), Diacryl Green 2BL (C.I. Basic Green 77), and Diacryl Violet BRL (C.I. Basic Violet 26).

2. Disperse dyes

Disperse dyes of the azo, anthraquinone, nitro, aminoquinone and methine types. Specific examples are Dianix Fast Orange R-FS, Dianix Fast Red B-FS, Dianix Red Brown R-FS, Kayalon Polyester Violet BNF (C.I. Disperse Violet 30), Kayalon Polyester Pink BSF (C.I. Disperse Red 55), Sumikalon Red FB (C.I. Disperse Red 60), Sumikalon Blue R (C.I. Disperse Blue 71), and Sumikalon Dark Blue RB (C.I. Disperse Blue 55).

3. Azoic dyes

As the azoic diazo component, there are C.I. Azoic Diazo Component 41, C.I. Azoic Diazo Component 48, C.I. Azoic Diazo Component 118, C.I. Azoic Diazo Component 124, C.I. Azoic Diazo Component 125, etc. As the azoic coupling component, there are C.I. Azoic Coupling Component 8, C.I. Azoic Coupling Component 11, C.I. Azoic Coupling Component 17, C.I. Azoic Coupling Component 35, etc. C.I. Azoic Red 79, C.I. Azoic Red 81, C.I. Azoic Blue 30, C.I. Azoic Green 1, and C.I. Azoic Brown 15 are also used.

4. Vat dyes

Vat dyes of the antraquinone and indigozoyl types. Specific examples are Caledon Orange Brown 2G (C.I. Vat Orange 14), Caledon Red B (C.I. Vat Red 41), Mikethrene Violet FFBN (C.I. Vat Violet 13), Nihonthrene Dark Blue BO (C.I. Vat Blue 20), Caledon Olive OMW (C.I. Vat Green 26), and Indanthrene Black Brown RV (C.I. Vat Brown 56).

The alkyl group represented by R, R' and R" in the general formula (I) expressing the amide compound to be incorporated in the dye liquor may be a straight-chain or branched chain alkyl group. Preferably, it is a lower alkyl group, especially an alkyl group of 1 to 3 carbon atoms, that is a methyl, ethyl, n-propyl or i-propyl group.

Examples of the amide compound include acetamide, acetomethyl amide, acetoethyl amide, acetopropyl amide, form-methyl amide, formethyl amide, formpropyl amide, formanilide, acetanilide, N,N-dimethyl formamide, N,N'-diethyl formanilide, N,N-dipropyl formamide, N,N-diphenyl formamide, N,N-dimethyl acetamide, N,N-diethylacetamide, N,N-dipropyl acetamide, N,N-diphenyl acetamide, benzamide, methylbenzamide, ethylbenzamide, propionbenzamide, N,N-dimethylpropionylamide, N,N-diethylpropionyl amide, N,N-diphenylpropionyl amide, N,N-dimethylbenzamide, N,N-diethylbenzamide, N,N'-dipropylbenzamide, N,N-diphenylbenzamide, propionamide, phenyl anilide, propionyl anilide, butylamide, and butylanilide. These amide compounds may be used alone or in admixture of two or more. Of these compounds, N,N'.THETA. dimethylformamide, N,N'-dimethylacetamide, N,N-diethyl formamide, N,N-diethylacetamide, N,N-diphenyl formamide, N,N-diphenyl acetamide, methylbenzamide, benzamide, benzanilide, acetanilide, ethylbenzamide, and propyl benzamide are preferred. Especially useful amide compounds are N,N-diethylformamide, N,N-dimethylacetamide and N,N-diethylacetamide.

The suitable concentration of the amide compound is generally from 3.0 to 50.0% based on the total weight of the dye liquor although it may differ depending upon the type, form and amount of the phenolic fibrous material to be colored. Preferably, the concentration is 15.0 to 40.0% by weight. Within this concentration range, the amide compound does not cause a deterioration in the physical properties of the phenolic fibrous material, nor does it pose any difficulty in dyeing operation. If the concentration of the amide compound exceeds 50%, the diffusion of the compound into the inner structure of the fibers is prevented because of its extremely great ability to dissolve the dye, which in turn causes a reduction in dyeability. Even if the dye is temporarily fixed to the material, it tends to be dissolved, and the resulting dyeings have only poor fastness characteristics. Furthermore, the amide compound has a strong action of swelling the phenolic fibers, and reduces the tenacity of the fibers. If, on the other hand, the concentration of the amide compound is less than 3 % by weight, the addition of the amide compound does not produce an improved dyeing effect.

The procedure for dyeing the phenolic fibrous material in accordance with the method of this invention does not differ from the conventional methods. Thus, the fibrous material can be dyed by the conventional dyeing method using a dye liquor containing a dye in the concentration described above and if desired, using a size such as tragacanth rubber or dextrin and a conventional additive.

In a preferred embodiment of the method of this invention, the suitable dyeing temperature (temperature of the dye bath) is 80.degree. to 140.degree.C., more preferably 100.degree. to 130.degree.C. when dip dyeing from an aqueous solution of a dye. If the temperature is below 80.degree.C., the swelling action of the phenol fibers is not sufficiently exhibited, and it becomes difficult to dye them uniformly in deep colors. On the other hand, if the temperature is higher than 140.degree.C., swelling occurs excessively to cause a reduction in the tenacity of the phenolic fibers or result in the decomposition of the amide compound.

When the pad dyeing process or printing process is utilized, a solution or paste-like matter (printing paste) containing a dye and the amide compound is padded on the material to be dyed or printed thereon, and then the material is treated with steam. The temperature of the steam is not critical, but preferably 110.degree. to 140.degree.C., more preferably 120.degree. to 130.degree.C. The steaming time is generally 10 minutes to 60 minutes.

The fibrous material so dyed is then washed, and dried. When a disperse dye is used, the dyed material is washed by a conventional method with an aqueous solution held at 60.degree.-80.degree.C. containing hydrosulfite (0.5 to 2 g/l), soda ash (0.3-1 g/l) and a nonionic surfactant (0.5-2 g/l) for about 20 to 30 minutes. When the material is colored with other dyes, the dyed material is desirably washed with an aqueous solution held at 60.degree.-80.degree.C. containing a nonionic surfactant (0.5 to 2g/l) for about 20 to 30 minutes. Since the amide compound generally tends to remain on the dyed fibers as a result of adsorption to it, it is essential to wash the material sufficiently free of the amide compound. The amide compound is somewhat flammable, and toxic to the skin, which results in a reduction in the commercial value of the fibrous product.

The action of the amide compound on the phenolic fibers is not a mere swelling action of a conventional carrier substance used in the dyeing of synthetic fibers such as phenol, dichlorobenzene, cresol or ethylene glycol, but also is an action of neutralizing negative charge on the surface of the fibers, causing the dye to be adsorbed to the fibers, and rendering it readily diffusible. Thus, in conjunction with its swelling action, this neutralizing action gives rise to an increased solubility of a dye or paste to give it an effect of dyeing the material in deep fast colors. This is clear from the fact that when a phenolic fibrous material is treated with a dye bath containing a swelling agent such as phenol, dichlorobenzene or cresol, it is not at all dyed. Furthermore, as is well known, phenolic fibrous materials are difficult to dye uniformly. However, in the present invention, the use of the amide compound can lead to the removal of this defect, and give a uniform dyeing.

In the conventional carrier dyeing of synthetic fibers, a surface active agent is usually added in order to better the dispersibility of the carrier and cause it to be adsorbed uniformly to the fibers. According to the present invention, the use of such a surfactant can be omitted, and even in the absence of the surfactant, it is possible to dissolve and disperse a dye or paste uniformly by the amide compound and promote the penetrability of the dye to provide a dyeing of uniform deep color.

Furthermore, the adsorption and diffusion of the dye can be promoted by the neutralization of negative charge on the surfaces of the phenolic fibers which is caused by the action of the amide compound. These derivatives cannot be expected from the conventional technique of dyeing the phenolic fibers.

The improvement of the dyeability of the phenolic fibrous material by the action of the amide compound of formula (I) is very remarkable, and the method so improved is commercially acceptable as such. The only difficultly with the amide compound is that the dyed material must be thoroughly washed in order to remove the amide compound completely from it.

We have however found that this difficulty can be overcome by incorporating, together with the amide compound, (i) at least one water-soluble metal sulfate, or (ii) at least one oxygen-containing compound selected from the group consisting of alkanols having 3 to 5 carbon atoms, benzyl alcohol, tetrahydrofurfuryl alcohol, dioxane, dialkyl ketones having 3 to 5 carbon atoms, cyclohexanone and lower alkyl esters of formic acid and acetic acid, or both (i) and (ii), in the dye liquor.

When the amide compound and the oxygen-containing compound is present in the dye liquor, a number of remarkable commercial advantages can be expected. For example, the diffusion of the dye into the phenolic fibrous material and its dyeability are remarkably improved by the synergistic effect of the amide compound and the oxygen-containing compound, even if the concentration of the amide compound is low. Also, there is a greatly reduced tendency of the amide compound to be adsorbed to the surfaces of the phenolic fibers. Therefore, by ordinary washing, the amide compound can be completely removed.

Thus, according to another aspect of this invention, there is provided a method for dyeing fibers composed of phenolic resins or their fibrous structures which comprises dyeing said fibers or fibrous structures using a dye liquor containing as a dyeing assistant (A) at least one amide compound expressed by the general formula ##EQU3## wherein R, R' and R" are the same or different and each represent a hydrogen atom, an alkyl group, a phenyl group, a benzyl group, or phenetyl group, but R, R' and R" do not represent hydrogen atoms at the same time, and (B) (i) at least one water-soluble metal sulfate, or (ii) at least one oxygen-containing compound selected from the group consisting of alkanols having 3 to 5 carbon atoms, benzyl alcohol, tetrahydrofurfuryl alcohol, dioxane, dialkyl ketones having 3 to 5 carbon atoms, cyclohexanone and lower alkyl esters of formic acid and acetic acid, or both (i) and (ii).

Any metal sulfates that are water-soluble can be used as component (B) (i) described above, and its selection will be obvious to those skilled in the art. Examples of the metal sulfates are sodium sulfate, potassium sulfate, beryllium sulfate, magnesium sulfate, aluminum sulfate, potassium alum (potassium aluminum sulfate), chromium sulfate, chlorium alum, ferrous sulfate, ferric sulfate, ferrous ammonium sulface, cobalt sulfate, and nickel sulfate. Sodium sulfate, potassium sulfate and potassium alum are especially preferred. These metal sulfates can be used either alone or in admixture of two or more.

The metal sulfate can be incorporated in a concentration of 3.0 to 35.0 %, preferably 10.0 to 30.0%, based on the total weight of the dye bath. If the concentration of the metal sulfate is in excess of 30.0%, it becomes difficult to dissolve in the dry liquor. If it is less than 3.0%, the addition of the sulfate cannot be expected to produce a dyeing effect, and moreover, the amide compound becomes easier to adsorb to the surface of the phenolic fibers, in which case the removal of the amide compound by washing is time-consuming.

The alkanols having 3 to 5 carbon atoms to be used together with the amide compound may, for example, be n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-amyl alcohol, and sec.-amyl alcohol. Examples of the dialkyl ketones having 3 to 5 carbon atoms are acetone, methyl ethyl ketone, and diethyl ketone. Examples of the lower alkyl esters of formic acid and acetic acid are methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. Especially, n-propanol, n-butanol, benzyl alcohol, dioxane and cyclohexanone are preferred.

The oxygen-containing compounds may be used alone or in admixture of two or more. Preferably, the oxygen-containing compound is miscible with the dye liquor. Thus, water-miscible oxygen-containing compounds are conveniently used in the present invention.

The oxygen-containing compound can be incorporated in the same concentration as the metal sulfate, that is, in a concentration of 3.0 to 35.0 % by weight based on the total weight of the dye liquor. Preferably, it is used in a concentration of 5.0 to 35.0 % by weight based on the total weight of the dye liquor. If the concentration of the oxygen-containing compound is lower than 3.0% by weight, sufficient effects obtainable by its addition cannot be expected. On the contrary, if it is higher than 30.0% by weight, the solubility of the dye becomes exceedingly high, and the diffusion of the dye into the fibers is prevented. This results in a reduction in dyeability, and even if the fibers can be temporarily dyed, the dye tends to bleed out. Furthermore, the swelling action of the oxygen-containing compound becomes strong, and causes a reduction of the tenacity of the fibers.

The metal sulfate and the oxygen-containing compound can be used separately or in combination. When both of them are used at the same time, the total amount of these compounds is 3.0 to 35.0% by weight.

The greatest advantage of this embodiment is that the amount of the amide compound which is difficult to remove by washing from the phenolic fibrous material can be remarkably reduced. In this embodiment of the invention, sufficiently improved dyeing effects can be obtained even if the amide compound is present in an amount as low as 3.0 to 10.0% by weight based on the total weight of the dye liquor, although this amount is not critical. Preferably, the concentration of the amide compound is 5.0 to 10.0% by weight.

In this embodiment wherein the metal sulfate or the oxygen-containing compound or both are used together with the amide compound, phenolic fibers can be colored in the same way as in the case of using the amide compound alone in the dye liquor, that is, by any of the dip dyeing, pad dyeing or printing process.

The action of the metal sulfate or the oxygen-containing compound is not clear. But it is presumed that it is not a mere swelling action of a conventional carrier substance, but serves to increase the solubility of the dye and promote the diffusion of the dye. In conjunction with the action of neutralizing negative charge on the surfaces of the fibers which is exhibited by the amide compound, these additional compounds can produce an effect of uniformly coloring the phenolic fibers in deep fast colors. However, the invention is in no way restricted by this presumption.

The amount of the amide compound can be markedly reduced by the addition of the metal sulfate and/or the oxygen-containing compound. Also, the adsorption of the amide compound to the fibers can be prevented by these additional compounds, to render it easy to remove the amide compound by washing.

According to the method of this invention, the phenolic fiberous materials heretofore considered difficult to dye can be colored uniformly in deep colors, and the dyeings have marked fastness characteristics. Furthermore, this method does not result in impairing the desirable incombustibility of the phenolic fibers.

The method of this invention is very advantageous commercially, because no additional step of dyeing is required.

The following Examples will illustrate the present invention further. Unless otherwise specified, all percentages are by weight.

The dye exhaustion shown in the Examples was determined by the following equation. ##EQU4## wherein A is the concentration in g/l of the dye in the dye solution before dyeing and B is the concentration in g/l of the dye after dyeing.

The dyeability (K/S) was determined by the Kubelka-Munk equation shown below. ##EQU5## where R is the reflectance of the sample dyeing.

The fastness to laundering was measured in accordance with JIS-L-1045, the fastness to rubbing in accordance with JIS-L-1048, and the fastness to light in accordance with JIS-L-1044.

The carbonized length was measured in accordance with the vertical method (JIS-L-1004) whereby the test cloth was maintained perpendicular and flames were caused to come in contact with the test cloth using a Bunsen burner for 12 seconds, and then the length of the carbonized portion of the test cloth was measured.

The presence of the amide compound remaining in the dyeing was examined by infrared absorption spectrum.

EXAMPLE 1

A plain weave fabric made up of single yarns of phenolic filaments obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with the following dye solution.

______________________________________ Artisil Violet 2RP (Color Index Number Disperse 1) 25% (o.w.f.) N,N'-diethylacetamide 30% (based on dye bath weight) Amount of dye solution: 100-fold the weight of material dyed. ______________________________________

The fabric was dipped in the dye bath, and the dyeing was started at 40.degree.C., the temperature being raised to 130.degree.C. during a period of 30 minutes, where the dyeing was carried out for 60 minutes. The fabric was then washed with water and thereafter treated for 20 minutes at 80.degree.C. with a reducing wash liquid consisting of 1 gram per liter of hydrosulfate, 1 gram per liter of soda ash, 1 gram per liter of Noigen HC (a nonionic surfactant produced by Daiichi Kogyo Seiyaku Co., Japan) and water, followed by water-washing and drying. The so obtained dyed fabric was dyed to a deep shade of purple. The dye exhaustion was 69.8%.

Next, dyeings were carried out under identical conditions as hereinabove indicated, using dye baths prepared in same manner, except that the content of N,N-diethylacetamide was varied as indicated in Table 1. The results obtained are shown in Table 1.

Table 1 ______________________________________ No. Content of amide type compound Dye exhaus- tion (%) ______________________________________ 1 N,N'-diethylacetamide 0 % 0 2 " 3 % 0 3 " 5 % 10.0 4 " 10 % 12.8 5 " 15 % 40.8 6 " 20 % 60.8 7 " 25 % 69.8 8 " 30 % 67.2 9 " 40 % 36.5 10 " 50 % 10.1 11 " 60 % 3.1 ______________________________________

As is apparent from the foregoing results, dyed products dyed evenly to a deep shade were obtained when the content of the N,N'-diethylacetamide was above 5 %. On the other hand, when the amount added was less than 5 % or in excess of 50 %, a marked decline in the rate of dye exhaustion was demonstrated.

Further, the ratings of colorfastness to light, laundering and crocking were respectively Classes 4, 4 and 5.

EXAMPLE 2 A top consisting of the same phenolic filaments as in Example 1 was dyed with the following dye solution.

______________________________________ Terasil Navy Blue - GRL (disperse dye produced by Ciba Company) 15 % (based on weight of material dyed) N,N'-dimethylacetamide 25 % (based on the dye bath weight) Amount of dye solution: 20-fold the weight of material dyed. ______________________________________

The top was dipped in the dye bath, and the dyeing was started at 30.degree.C., after which the temperature was raised to 120.degree.C. during a period of 30 minutes, where the dyeing was carried out for 90 minutes followed by water-washing. The top was then treated for 20 minutes at 80.degree.C. with a reducing wash liquid consisting of 1 gram per liter of hydrosulfite, 0.5 gram per liter of soda ash, 1 gram per liter of a nonionic surfactant and water, after which the top was water-washed and dried. The so obtained dyed product was dyed to a deep shade of blue, and the dye exhaustion was 90.5 %.

The foregoing experiment was repeated for comparison of the instance when the N,N'-dimethylacetamide was not added and the instance where phenol, benzyl alcohol or metadichlorobenzene was added instead of N,N'-dimethylacetamide. The results obtained are shown in Table 2.

Table 2 ______________________________________ Dye exhaus- No. Additve (%) tion (%) ______________________________________ 1 N,N'-dimethylacetamide 25 % 90.5 2 not added 0 % 0 3 phenol 20 % 2.0 4 benzyl alcohol 20 % 3.1 5 metadichlorobenzene 20 % 0 ______________________________________

As can be seen from the foregoing results, a dyed product dyed evenly to a deep shade was obtained when N,N'-dimethylacetamide was added, but in the case where the N,N'-dimethylacetamide was not added dyeing was not possible. Further, even though a carrier such as phenol, benzyl alcohol or metadichlorobenzene was added, the dye uptake was either nil or small. From this results, it can be seen that the effect of the amide type compound, as used in the present invention, is not that merely of a carrier.

Further, the ratings of colorfastness to light, laundering and crocking were respectively Classes 4, 4 and 5.

EXAMPLE 3

A knit fabric made up the phenolic filaments of Example 1 was dyed in a dye bath of the following composition.

______________________________________ Terasil Brilliant Pink 2Gl (disperse dye produced by Ciba Company) 30 % (o.w.f.) N,N'-dimethylformamide 27 % (based on the dye bath weight) Amount of dye solution: 60-fold the weight of fabric dyed. ______________________________________

The fabric was dipped in the dye bath, and the dyeing was started at 40.degree.C., after which the temperature was raised up to 100.degree.C. during a period of 30 minutes, where the dyeing was continued for 60 minutes. The fabric was then water-washed and thereafter treated for 20 minutes at 80.degree.C. in a reducing wash bath consisting of 1 gram per liter of hydrosulfite, 1 gram per liter of soda ash, 1 gram per liter of a nonionic surfactant and water, followed by water-washing and drying. The so obtained dyed fabric was dyed to a red shade.

The experiment was carried out by operating in the same manner as described above but without adding N,N'-dimethylformamide or adding formaldehyde instead of N,N'-dimethylformamide. The results obtained are shown in Table 3.

Table 3 ______________________________________ Dye exhaus- No. Additive (%) tion (%) ______________________________________ 1 N,N'-dimethylformamide 27 % 69.8 2 not added 0 % 0 3 formaldehyde 10 % 0 4 " 20 % 2.0 5 " 30 % 2.5 ______________________________________

As is apparent from the foregoing results, the material to be dyed could be dyed evenly to a deep shade when the N,N'-dimethylformamide was added but could not be dyed at all when it was not added. On the other hand, when formaldehyde was used instead of N,N'-dimethylformamide, either the material was not dyed at all or only slightly dyed at the several concentrations in which the formaldehyde was used.

EXAMPLE 4

A curtain material made up of the same phenolic yarn as that of Example 1 was dyed in a dye solution of the following composition.

______________________________________ Sumiacryl Blue E-6G (cationic dye produced by Sumitomo Chemical Co.) 15 % (o.w.f.) Acetanilide 20 % (based on the dye bath weight) Amount of dye solution: 50-fold the weight of material dyed. ______________________________________

After starting the dyeing at 40.degree.C., the temperature was raised up to 125.degree.C. during a period of 30 minutes, and then the dyeing was continued for 60 minutes at this temperature. The dyed material was then water-washed and thereafter washed for 20 minutes at 80.degree.C. in a wash liquid consisting of an aqueous solution of 1 gram per liter of a nonionic surfactant. This was followed by water-washing and drying the material. The so obtained dyed fabric was dyed a blue shade.

The experiment was carried out by operating in the same manner as described above but using instead of the acetanilide either N,N'-diphenylformamide, N,N'-diphenylacetamide, methylbenzamide, N,N'-diethylformamide or N,N'-dimethylbenzamide. The results obtained are shown in Table 4.

Table 4 ______________________________________ No. Additive (%) Dye exhaustion (%) ______________________________________ 1 acetanilide 20 87.5 2 N,N'-diphenylformamide 20 86.0 3 N,N'-diphenylacetamide 20 79.6 4 methylbenzamide 20 82.1 5 N,N'-diethylformamide 20 72.5 6 N,N'-dimethylbenzamide 20 81.5 7 not added 0 0 ______________________________________

As is apparent from the foregoing results, it was possible to accomplish the dyeing to a deep shade and moreover evenly when either acetanilide, N,N'-diphenylformamide, N,N'-diphenylacetamide, methylbenzamide, N,N'-diethylformamide or N,N'-dimethylbenzamide was added.

EXAMPLE 5

A 2-ply weaving yarn consisting of the phenolic filaments of Example 1 was dyed with a dye solution of the following composition.

______________________________________ TD Black B2S (diazo component produced by Daito Chemical Co., 20 % (based on weight Japan) of material dyed) TD 1200 - 2S (coupling component 30 % (based on weight produced by Daito Chemical Co.) of material dyed) Benzamilide 30 % (based on weight of dye bath) Amount of dye solution: 20-fold the weight of material dyed. ______________________________________

After starting the dyeing at 30.degree.C., the temperature was raised to 115.degree.C. during a period of 20 minutes, at which temperature the dyeing was continued for 90 minutes and followed by washing the dyed yarn in water and then in hot water. The yarn was then developed by diazotizing for 30 minutes at 100.degree.C. in a diazotizing coupling bath consisting of 10 % (based on weight of material dyed) of sulfuric acid and 9 % (based on weight of material dyed) of sodium nitrite, after which the yarn was water-washed and dried. The so obtained dyed product was dyed to a deep shade of black.

The foregoing procedure was repeated except that either benzamide, methyl benzamide, ethyl benzamide, propyl benzamide, N,N'-diethylbenzamide, N,N'-dipropylbenzamide was added instead of benzanilide, with the results shown in Table 5.

Table 5 ______________________________________ No. Additive (%) Dye exhaustion (%) ______________________________________ 1 benzanilide 30 76.5 2 benzamide 30 68.9 3 methylbenzamide 30 72.8 4 ethylbenzamide 30 69.5 5 propylbenzamide 30 43.8 6 N,N'-diethylbenzamide 30 60.5 7 N,N'-dipropylbenzamide 52.1 8 not added 0 0 ______________________________________

As can be seen from the foregoing results, the yarn was dyed to a deep shade when either benzanilide, benzamide, methylbenzamide, ethylbenzamide, propylbenzamide, N,N'-diethylbenzamide or N,N'-dipropylbenzamide was added.

EXAMPLE 6

A tweed made up of 2-ply yarn of the phenolic filaments of Example 1 was dyed with a dye bath of the following composition.

______________________________________ Foron Black S-2BL (disperse dye produced by Sandoz Company) 17 % (o.w.f.) Acetoethylamide 22 % (based on weight of dye bath) Amount of dye bath: 150-fold the weight of material dyed. ______________________________________

After starting the dyeing at 20.degree.C., the temperature was raised up to 100.degree.C. during a period of 60 minutes followed by washing the dyed material in water. The dyed fabric was then submitted to a reductive washing for 20 minutes at 80.degree.C. in a reduction wash bath consisting of 1 gram per liter of hydrosulfite, 0.5 gram per liter of soda ash, 1 gram per liter of Noigen HC (nonionic surfactant) and water followed by water-washing and drying. The so obtained dyed fabric was dyed to deep shade of black tinged with blue.

The foregoing experiment was repeated except that either acetopropylamide or acetonilide was added instead of the acetoethylamide. The results obtained are shown in Table 6.

Table 6 ______________________________________ No. Additive (%) Dye exhaustion (%) ______________________________________ 1 not added 0 2 acetoethylamide 22 75.6 3 acetopropylamide 20 68.5 4 acetoanilide 20 70.1 ______________________________________

As is apparent from the foregoing results, the fabric was dyed to a deep shade as well as evenly when either acetoethylamide, acetopropylamide or acetoanilide was added.

EXAMPLE 7

A twill fabric made up 2-ply yarn of the phenolic filaments of Example 1 was printed with a printing paste of the following composition and thereafter submitted to a steaming treatment.

______________________________________ Dianix Black 2GSE (disperse dye produced by Mitsubishi Chemical Co.) 300 grams N,N'-dimethylacetamide 200 grams Duckalgine (sodium alginate size produced by Kamogawa Chemical Co., 50 grams Japan) Water 450 grams Viscosity 5200 centipoises ______________________________________

After carrying out the printing of the printing paste by means of the screen printing technique, the fabric was immediately steamed for 30 minutes at 130.degree.C. and then water-washed. This was followed by washing the fabric for 20 minutes at 80.degree.C. in an aqueous solution of 1 gram per liter of a nonionic surfactant, after which it was washed with water and dried.

By way of comparison, the experiment was repeated but without adding the N,N'-dimethylacetamide. The results obtained are shown in Table 7.

Table 7 ______________________________________ No. Additives (%) Dye exhaustion (%) ______________________________________ 1 not added 0 2 N,N'-dimethylacetamide 61.5 ______________________________________

As is apparent from the foregoing results, a printed product dyed to a deep shade was obtained when the N,N'-dimethylacetamide was added but was not dyed at all when it was not added.

EXAMPLE 8

A plain weave fabric comprising fibers obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with a dye solution of the following composition.

______________________________________ Sumikalon Violet R (C.I. Disperse Violet 22) 20 % (o.w.f.) N,N'-dimethylformamide added in an amount as previously indicated. (based on weight of dye bath) Sodium sulfate added in amounts indicated in Table 8. Amount of dye solution: 50-fold the weight of material dyed. ______________________________________

The material to be dyed was dipped in the dye bath, and its dyeing was started at a temperature of 40.degree.C., after which the temperature was raised up to 130.degree.C. during a period of 30 minutes, at which temperature the dyeing was continued for 60 minutes. The material was then waterwashed and thereafter submitted to a reductive washing for 20 minutes at 80.degree.C. in a reduction wash liquid consisting of 1 gram per liter of hydrosulfite, 1 gram per liter of said ash, 1 gram per liter of "Noigen" HC and water followed by water-washing and drying. The results obtained are shown in Table 8.

Table 8 __________________________________________________________________________ Additive Dye Length of Residual No. N,N'- sodium exhaustion carboni- N,N'-dimethyl- dimethyl- sulfate zation formamide formamide (%) (%) (cm) __________________________________________________________________________ 1 10 0 10.2 16.2 no 2 10 3 35.6 16.2 no 3 10 10 44.8 16.0 no 4 10 20 52.2 16.3 no 5 10 30 54.9 16.2 no 6 10 50 11.8 16.2 no 7 0 30 0 16.0 no 8 2 30 5.8 16.0 no 9 20 30 58.7 19.1 yes 10 20 0 53.5 20.0 yes 11 not added 0 15.8 no 12 not dyed -- 13.2 no __________________________________________________________________________

As is apparent from the results of the dye exhaustion measurements shown in Table 8, the dye exhaustion is exceedingly small when sodium sulfate is not added to the dye solution containing 10 % of N,N'-dimethylformamide but becomes increasingly greater as the sodium sulfate is added in increasingly greater amounts of 3 %, 10 %, 20 % and 30 %.

However, the addition of the sodium sulfate in an amount of 50 % is not to be desired, for difficulty is experienced in its dissolution and moreover the rate of dye exhaustion drops. Thus, even in the case of a 10 % N,N'-dimethylformamide solution, dyeing effects equal to the case where a 20 % N,N'-dimethylformamide solution has been used can be obtained by the addition of 10-30 % of sodium sulfate. Further, from the fact that no dye exhaustion effects are demonstrated when the dyeing is conducted with the use of the N,N' -dimethylformamide in an amount of 10 % or the sodium sulfate in an amount of 30 % independently of each other, the synergistic effects due to the conjoint use of these two components are obvious.

On the other hand, when the length of carbonization resulting from burning was measured, the fabric dyed in accordance with the invention method demonstrated a length of carbonization of the same degree as that of the undyed fabric. It is thus clear that the fabric dyed according to the invention method possesses fire resistance.

The colorfastness ratings to light, laundering and crocking were respectively Classes 3-4, 4 and 5.

EXAMPLE 9

A 2-ply yarn consisting of filaments obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with a dye solution of the following composition.

Sumikalon Violet R (C.I.: 20 % (based on weight of Disperse Violet 22 material dyed) N,N'-diethylformamide 8 % (based on weight of dye bath) Water-soluble metal sulfate 20 % (based on weight of indicated in Table 9 dye bath)

The material to be dyed was dipped in each of the dye solutions containing the several salts, and the dyeing of the material was carried out by starting the dyeing at 40.degree.C., after which the temperature was raised up to 130.degree.C. during a period of 30 minutes, at which temperature the dyeing was continued for a further 60 minutes. The dyed material was then washed in water and thereafter submitted to a reductive washing for 20 minutes at 80.degree.C. in a solution consisting of 1 gram per liter of hydrosulfite, 1 gram per liter of soda ash, 1 gram per liter of a nonionic surfactant and water followed by water-washing and drying. The dyeing and reductive washing were carried out in liquids amounting to 50-fold the weight of the material treated. The results of these dyeings are shown in Table 9.

Table 9 __________________________________________________________________________ Additive Dye Residual No. N,N'-diethyl- Sulfates Amount exhaustion N,N'-diethyl- formamide added formamide (%) (%) (%) __________________________________________________________________________ 1 8 sodium sulfate 20 54.7 no 2 8 potassium sulfate 20 51.7 no 3 8 magnesium sulfate 20 54.7 no 4 8 aluminum sulfate 20 48.4 no 5 8 cobalt sulfate 20 38.5 no 6 8 nickel sulfate 20 35.8 no 7 8 potassium alum 20 45.6 no 8 8 -- -- 8.6 yes 9 20 -- -- 40.5 yes __________________________________________________________________________

As is apparent from the foregoing results, whereas there is practically no dye exhaustion when only 8 % of N,N'-diethylformamide is contained in the dye solution, a marked improvement is demonstrated when 20 % of the various salts are used conjointly in the dye solution with 8 % of N,N'-dimethylformamide, an even higher rate of dye exhaustion than in the case of a dye solution containing 20 % of N,N'-diemthylformamide being demonstrated especially when either sodium sulfate, potassium sulfate, magnesium sulfate, potassium aluminum sulfate or potassium alum is added. Again, a rate of dye exhaustion of about the same degree is demonstrated when cobalt sulfate or nickel sulfate is used. Further, the concentration (amount used) of the N,N' -diethylformamide can be greatly reduced by about one-half or more. In addition, the defect that the flame spreads during burning due to the adhesion of the amide compound is also improved.

EXAMPLE 10

A tweed fabric made up of 2-ply yarn consisting of the phenolic filaments of Example 8 was dipped in a dye solution consisting of 20 % (o.w.f.) of Sumikalon Blue GR (CI: Disperse Blue 55 produced by Sumitomo Chemical Company), 10 % (based on weight of dye solution) of methylbenzamide, and 20 % (based on weight of dye solution) of a salt indicated in Table 10. The dyeing was started at 40.degree.C., and the temperature was raised up to 110.degree.C. during a period of 30 minutes, at which temperature the dyeing was continued for a further 90 minutes. The so dyed fabric was then washed in water and thereafter submitted to a reductive washing for 20 minutes at 80.degree.C. in a solution consisting of 1 gram per liter of hydrosulfite, 1 gram per liter of soda ash, 1 gram per liter of a nonionic surfactant and water followed by water-washing and drying. The dyeing and reductive washing were carried out in liquids amounting to 50-fold the weight of the material treated. The results obtained are shown in Table 10.

Table 10 __________________________________________________________________________ Additive Dye Length of Methyl- Amount Exhaus- Residual carboni- benzamide added tion methyl- zation No. (%) Salt added (%) (%) benzamide (cm) __________________________________________________________________________ 1 10 -- 3.8 No. 12.1 2 10 sodium 20 52.5 No 10.5 sulfate 3 10 sodium 20 2.7 No 10.5 acetate 4 10 sodium 20 3.2 No 10.6 carbonate 5 10 sodium 20 2.9 No 10.6 phosphate 6 10 lead acetate 20 3.7 No 10.7 7 10 magnesium 20 4.4 No 10.8 chloride 8 undyed -- -- 0 No 10.2 fabric 9 20 -- -- 50.1 Yes 12.5 __________________________________________________________________________

As is apparent from the foregoing results, a marked improvement in the rate of dye exhaustion is noted when 10 % of methylbenzamide and 20 % of sodium sulfate are conjointly used, the rate being equivalent to that were the methylbenzamide is used alone in an amount of 20 %. However, in the case of the salts other than sulfate, such, as for example, sodium acetate, sodium carbonate, sodium phosphate, lead acetate and magnesium chloride, the rate of dye exhaustion is exceedingly low and hence is of no practical use. Thus, it can be seen that the effectiveness of the conjoint use of a salt is only possible in the case where a sulfate is used, its effects being obvious from the above results.

EXAMPLE 11

A curtain material made up of single yarns consisting of the phenolic resin of Example 8 was dipped in a dye solution consisting of 30 % of Diacryl Pink FG (cationic dye produced by Mitsubishi Chemical Company), 8 % of N,N'-dimethylformamide, 25 % of sodium sulfate, 1 % of sodium cetyl sulfate (penetrant) and 36 % of water and, after padding, was rolled up and immediately steamed for 60 minutes at 120.degree.C. This was followed by washing the material in water and thereafter washing it for 20 minutes in a wash liquid (80.degree.C.) consisting of an aqueous solution of 1 gram per liter of a nonionic surfactant followed by water-washing and drying. By way of comparison, the foregoing experiment was repeated. In one case the experiment was carried out without adding the N,N'-dimethylformamide; in another case, without adding the sodium sulfate; and in still another case, without adding either of these components. The results obtained are shown in Table 11.

Table 11 __________________________________________________________________________ Length of Residual Dye- carboni- N,N'-dimethyl- ability zation formamide No. Additive (K/S) (cm) __________________________________________________________________________ The case where N,N'- 1 dimethylformamide 0.23 16.0 No and sodium sulfate were not added 2 Invention method 12.91 16.0 No The case where only 3 N,N'-dimethylform- 0.35 16.0 No amide was not added The case where only 4 sodium sulfate was 0.59 17.5 Yes not added __________________________________________________________________________

As is apparent from the foregoing results, the material was dyed to a deep shade and moreover evenly when conjoint use was made of the N,N' -dimethylformamide and sodium sulfate (invention method). However, in the case where N,N'-dimethylformamide was not added or where sodium sulfate was not added, there was substantially no dye uptake. Further, in the combustion test, the length of carbonization of the dyed product according to the invention method was short as in the case where the dyeing was carried out without adding the other components, thus demonstrating the fire resistance possessed by the product dyed according to the invention method.

EXAMPLE 12

A knit fabric made up of single yarns of the phenolic filaments of Example 8 was printed by means of the screen printing technique with a printing paste consisting of 30 % of Dianix Fast Dark Green B (disperse dye produced by Mitsubishi Chemical Co.), 10 % of acetanilide, 10 % of potassium sulfate, 5 % of propyl alginate (thickener) and 45 % of water and having a viscosity of 6000 centipoises, after which the fabric was immediately steamed for 40 minutes at 130.degree.C. The fabric was then washed in water and thereafter washed for 20 minutes in a wash liquid consisting of an aqueous solution containing 1 gram per liter of hydrosulfite, 0.5 gram per liter of soda ash and 1 gram per liter of a nonionic surfactant followed by water-washing and drying.

The foregoing experiment was repeated but without adding the acetanilide or potassium sulfate. The results are shown in Table 12.

Table 12 ______________________________________ Length of Resi- Dye- carboni- dual ability zation acetan- No. Additive (K/S) (cm) ilide ______________________________________ The case where acet- 1 anilide and potassium 0.23 17.2 No sulfate were not added 2 Invention method 11.52 17.2 No The case where only 3 acetanilide was not 0.37 17.2 No added The case where only 4 potassium sulfate 0.48 18.2 Yes was not added ______________________________________

It can be seen from the foregoing results that a printed product having beautiful clear-cut patterns of green was obtained when conjoint use of acetanilide and potassium sulfate was made but that in the case where the acetanilide was not added or the potassium sulfate was not added there was substantially no dye uptake. Further, there was no change in the length of carbonization in either of the cases.

EXAMPLE 13

A plain weave fabric made up of yarns obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with a dye solution of the following composition.

______________________________________ Dianix Brilliant Red BS-E 12 % (disperse dye produced by Mitsubishi Chemical CO.) N,N'-dimethylformamide added in an amount indicated in Table 13 (based on weight of dye solution) Benzyl alcohol added in an amount indicated in Table 13 (based on weight of dye solution) Amount of dye solution: 50-fold the weight of material dyed. ______________________________________

The material to be dyed was dipped in the dye bath, and the dyeing was started at 40.degree.C., after which the temperature was raised up to 130.degree.C. during a period of 30 minutes. The dyeing was continued for a further 60 minutes at this temperature. This was followed by washing the material in water and thereafter submitting the material to a reductive washing for 20 minutes at 80.degree.C. with a reduction wash liquid consisting of 1 gram per liter of hydrosulfate, 1 gram per liter of soda ash, 1 gram per liter of a nonionic surfactant and water followed by water-washing and drying. The results obtained are shown in Table 13.

Table 13 ______________________________________ Additive and concentration thereof Dye Residual N,N'-dimethyl- benzyl Exhaus- N,N'-dimethyl- No. formamide (%) alcohol tion formamide (%) (%) ______________________________________ 1 0 3 3.5 No 2 0 10 35.1 " 3 0 30 7.2 " 4 0 50 7.5 " 5 3 0 0 " 6 3 3 8.9 " 7 3 10 36.2 " 8 3 30 8.1 " 9 3 50 7.5 " 10 5 0 11.5 " 11 5 3 41.5 " 12 5 5 53.6 " 13 5 10 56.7 " 14 5 30 26.8 " 15 5 50 10.8 " 16 10 0 15.1 " 17 10 1 16.2 " 18 10 3 39.8 " 19 10 5 89.9 " 20 10 10 92.5 21 10 30 21.1 " 22 10 50 12.0 " 23 50 0 11.5 Yes 24 50 3 12.1 " 25 50 5 13.1 " 26 50 10 9.6 " 27 50 30 7.5 " 28 50 50 0 29 60 0 9.1 " 30 60 3 6.0 " 31 60 5 4.5 " 32 60 10 3.2 " 33 60 30 0 " 34 not added 2.1 No ______________________________________

As is apparent from the foregoing results, an adequate dye uptake cannot be achieved when the content of the N,N'-dimethylformamide is less than 3 %. On the other hand, when the content of N,N'-dimethylformamide exceeds 50 %, the dye uptake is likewise low. Further, there arises the necessity for more thorough washing, since the N,N'-dimethylformamide remains behind. On the other hand, when benzyl alcohol is conjointly used the range of 5-30 % under the conditions of no residual N,N'-dimethylformamide, a marked improvement is noted in the rate of dye exhaustion, whereas if the benzyl alcohol is used in an amount less than 3 % of in excess of 50 %, no dye uptake effects are demonstrated.

EXAMPLE 14

A 2-ply yarn consisting of filaments obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with a dye solution of the following composition.

______________________________________ Kayalon Polyester Dark 20 % (based on Brown TSF (disperse weight of yarn) dye produced by Nippon Kayaku Co.) N,N'-dimethylacetamide amount added as indicated in Table 14 (% based on weight of dye solution) Dioxane amount added as indicated in Table 14 (% based on weight of dye solution) Amount of dye solution: 20-fold the weight of the material dyed. ______________________________________

The yarn to be dyed was dipped in the dye solution, and the dyeing was started at 40.degree.C., after which the temperature was raised up to 130.degree.C. during a period of 30 minutes, and the dyeing was continued for a further 60 minutes at this temperature. This was followed by water-washing the yarn and thereafter washing it for 20 minutes at 80.degree.C. in a wash liquid containing 1 gram per liter of hydrosulfite, 0.5 gram per liter of soda ash and 1 gram per liter of a nonionic surfactant followed by water-washing and drying. The results obtained are shown in Table 14.

Table 14 ______________________________________ Additive and concentration thereof (%) Dye N,N'-dimethyl- Exhaus- Residual No. acetamide dioxane tion N,N'-dimethyl (%) acetamide ______________________________________ 1 0 10 7.9 No 2 0 30 15.8 " 3 5 0 17.1 " 4 5 5 56.2 " 5 5 10 77.7 " 6 5 30 81.6 " 7 5 50 18.5 " 8 10 0 23.6 9 10 5 70.1 " 10 10 10 86.5 " 11 10 30 28.6 " 12 10 50 10.0 " 13 50 5 17.1 Yes 14 50 10 15.1 " 15 60 5 11.2 " 16 not added 3.1 No ______________________________________

As is apparent from the foregoing results, the rate of dye exhaustion is low when the N,N'-dimethylacetamide is not contained or when it exceeds 50 %, even though conjoint addition is made of dioxane. In addition, residual N,N'-dimethylacetamide is noted. On the other hand, when either 5 % or 10 % of N,N'-dimethylacetamide is conjointly used with dioxane, marked dye uptake effects are noted with a dioxane content of 5-30 %. Moreover, no residual N,N'-dimethylacetamide is noted.

EXAMPLE 15

A knit fabric made up of 2-ply yarn of filaments obtained by melt-spinning a novolak type phenolic resin was dyed with a dye solution of the following composition.

______________________________________ Terasil Brilliant Pink FG 18 % (o.w.f.) (disperse dye produced by Ciba-Geigy Co.) Various compounds indicated amount added as in Table 15 indicated in Table 15 (based on weight of dye solution) Amount of dye solution: 20-fold the weight of material dyed. ______________________________________

After dipping the foregoing fabric in the dye solution and starting the dyeing at 40.degree.C., the temperature was raised up to 130.degree.C. during a period of 40 minutes, and the dyeing was continued for a further 60 minutes at this temperature. The fabric was then water-washed and thereafter washed for 20 minutes at 80.degree.C. in a wash liquid containing 1 gram per liter of hydrosulfite, 0.5 gram per liter of soda ash, 0.8 gram per liter of a nonionic surfactant and water followed by water-washing and drying. The results are shown in Table 15.

Table 15 __________________________________________________________________________ N,N'-dimethyl- N,N'-dimethyl- Concent- Dye formamide acetamide ration Exhaus- No. (%) (%) Additive (%) tion (%) __________________________________________________________________________ 1 8 -- benzyl 6 89.1 alcohol 2 8 -- n-propanol 6 82.1 3 8 -- iso-propanol 6 71.2 4 8 -- n-butanol 6 72.5 5 8 -- iso-butanol 6 70.0 6 8 -- dioxane 6 81.5 7 8 -- cyclo- 6 69.7 hexane 8 8 -- acetone 6 63.5 9 8 -- -- -- 5.0 10 -- 8 benzyl 6 82.6 alcohol 11 -- 8 n-propanol 6 80.5 12 -- 8 iso-propanol 6 69.1 13 -- 8 n-butanol 6 67.2 14 -- 8 iso-butanol 6 59.8 15 -- 8 dioxane 6 79.1 16 -- 8 cyclo- 6 58.1 hexane 17 -- 8 acetone 6 41.5 18 -- 8 -- -- 8.0 19 -- -- -- -- 0 __________________________________________________________________________

As is apparent from the foregoing results, although the rate of dye exhaustion is low in the case of a dye solution containing only 8 % of either N,N'-dimethylformamide or N,N'-dimethylacetamide, it is obvious that by the conjoint use of 6 % of benzyl alcohol, n-propanol, iso-propanol, n-butanol, iso-butanol, dioxane, cyclohexane or acetone the rate of dye exhaustion is greatly improved.

EXAMPLE 16

A twill fabric made up of filaments obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with a dye solution of the following composition.

______________________________________ Sumiacryl Red 7B (cationic dye 18 % (o.w.f.) produced by Sumitomo Chemical Co.) N,N'-dimethylformamide 10 % (based on weight of dye solution) Various compounds indicated in Table 16 8 % (based on weight of dye solution) Amount of dye solution : 50-fold the weight of material dyed. ______________________________________

The foregoing fabric was dipped in the dye solution, and the dyeing was started at 40.degree.C., after which the temperature was raised up to 110.degree.C. during a period of 30 minutes, at which temperature the dyeing was continued for a further 80 minutes. The fabric was then washed in water and thereafter washed for 20 minutes at 70.degree.C. in a wash liquid containing 1 gram per liter of a nonionic surfactant followed by waterwashing and drying. The results are shown in Table 16.

Table 16 ______________________________________ Dye Ex- N,N'-dimethyl Concent- haustion No. formamide (%) Additive ration (%) (%) ______________________________________ 1 10 n-propanol 8 90.8 2 10 iso-propanol 8 81.2 3 10 n-butanol 8 83.5 4 10 iso-butanol 8 78.6 5 10 methanol 8 9.1 6 10 methanol 30 8.2 7 10 ethanol 8 5.2 8 10 ethanol 30 4.5 9 10 -- -- 3.5 ______________________________________

As is apparent from the results shown above, the rate of dye exhaustion is low in the case of a dye solution containing only 10 % of N,N'-dimethylformamide but shows a marked improvement when 10 % of the N,N'-dimethylformamide is conjointly used with n-propanol, iso-propanol, n-butanol or iso-butanol. On the other hand, the conjoint use of methanol or ethanol was of no use in improving the rate of dye exhaustion. Thus, the effects of the conjoint use of either n-propanol, iso-propanol, n-butanol or iso-butanol are obvious.

EXAMPLE 17

A plain weave fabric made up of yarns of phenolic filaments obtained by melt-spinning a novolak type phenolic resin and thereafter curing with formaldehyde was dyed with the following dye solution.

______________________________________ Dianix Brown P-E (disperse dye 15 % (o.w.f.) produced by Mitsubishi Chemical Co.) N,N'-dimethylformamide 8 % (based on dye bath weight) Various compounds indicated in Table 17 8 % (based on weight of dye solution) Amount of dye solution: 30-fold the weight of material dyed. ______________________________________

The fabric was dipped in the dye bath and the dyeing was started at 40.degree.C., the temperature being raised to 128.degree.C. during a period of 40 minutes, where the dyeing was carried out for 80 minutes. The fabric was then washed in water and thereafter treated for 20 minutes at 80.degree.C. with a reducing wash liquid containing 0.8 gram per liter of hydrosulfite, 0.4 gram per liter of soda ash and 1 gram per liter of a nonionic surfactant, followed by water-washing and drying. The results obtained are shown in Table 17.

Table 17 __________________________________________________________________________ Dye N,N'-dimethyl Concent- Exhaus- formamide ration tion No. (%) Additive (%) (%) __________________________________________________________________________ 1 8 n-amyl alcohol 8 76.5 2 8 tetrahydrofurfuryl 8 69.8 alcohol 3 8 methyl ethyl ketone 8 70.2 4 8 diethyl ketone 8 58.6 5 8 methyl formate 8 62.1 6 8 ethyl formate 8 68.2 7 8 propyl formate 8 50.2 8 8 methyl acetate 8 60.5 9 8 ethyl acetate 8 79.3 10 8 propyl acetate 8 58.2 11 8 butyl acetate 8 53.6 12 8 none 0 7.6 13(Control) 0 n-amyl alcohol 8 12.6 14 0 tetrahydrofurfuryl 8 10.5 alcohol 15 0 methyl ethyl ketone 8 8.8 16 0 diethyl ketone 8 2.6 17 0 methyl formate 8 5.4 18 0 ethyl formate 8 6.2 19 0 propyl formate 8 3.2 20 0 methyl acetate 8 6.5 21 0 ethyl acetate 8 15.1 22 0 propyl acetate 8 7.1 23 0 butyl acetate 8 2.1 24 0 none 0 0 __________________________________________________________________________

As is apparent from the foregoing results although the rate of dye exhaustion is low in the case of a dye solution containing only N,N'-dimethylformamide, it is obvious that by the conjoint use of 8 % of n-amyl alcohol, tetrahydrofurfuryl alcohol, methyl ethyl ketone, diethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate or butyl acetate the rate of dye exhaustion is greatly improved.

Claims

What we claim is:

1. A method for coloring fibers or fibrous structures composed of phenolic resins, which comprises coloring said fibers or fibrous structures using a dye liquor which contains as a dyeing assistant at least one amide compound of formula ##EQU6## wherein R, R' and R" are the same or different and each represent a hydrogen atom, an alkyl group, a phenyl group, a benzyl group or a phenetyl group, but R, R' and R" do not represent hydrogen atoms at the same time.

2. The method of claim 1 wherein the amount of the amide compound is 3 to 50% by weight based on the total weight of the dye liquor.

3. The method of claim 1 wherein said amide compound is selected from compounds of formula (I) wherein R, R' and R" are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a phenyl group and a benzyl group and R, R' and R" do not represent hydrogen atoms at the same time.

4. The method of claim 3 wherein said amide compound is selected from the group consisting of N,N-dimethyl formamide, N,N-dimethyl acetamide, N,N-diethyl formamide, N,N-diethyl acetamide, N,N-diphenyl formamide, N,N-diphenyl acetamide, methyl benzamide, benzanilide, benzamide, acetanilide, ethyl benzamide and propyl benzamide.

5. The method of claim 1 wherein said dye liquor contains at least one metal sulfate

6. The method of claim 5 wherein the amount of said metal sulfate is 3 to 35% by weight based on the total weight of the dye liquor and the amount of amide compound is 3 to 10% by weight based on the total amount of the dye liquor.

7. The method of claim 5 wherein said dye liquor is a printing paste containing a dye.

8. The method of claim 5 wherein said metal sulfate is selected from the group consisting of sodium sulfate, potassium sulfate, beryllium sulfate, magnesium sulfate, aluminum sulfate, potassium alum, chromium sulfate, chromium alum, ferrous sulfate, ferric sulfate, ferrous ammonium sulfate, cobalt sulfate and nickel sulfate.

9. The method of claim 1 wherein said dye liquor is in the form of solution containing a dye.

10. The method of claim 9 wherein said dye is a disperse dye, azoic dye, cationic dye or vat dye.

11. The method of claim 1 wherein dyeing is carried out by dip dyeing, pad dyeing or printing method.

12. The method of claim 11 wherein said dip dyeing is carried out at a bath temperature of 80.degree. to 140.degree.C.

13. The method of claim 11 wherein said pad dyeing is carried out by padding a paste-like dye liquor on the phenolic fibers of fibrous structures, and then steaming them for 10 to 60 minutes at 110.degree. to 140.degree.C.

14. The method of claim 7 wherein dyeing is carried out by printing method by applying said paste-like dye liquor to the phenolic fibers or fibrous structures, and then steaming them at 110.degree. to 140.degree.C. for 10 to 50 minutes.

15. The method of claim 1 wherein said dye liquor further contains at least one oxygen-containing compound selected from the group consisting of alkanols having 3 to 5 carbon atoms, benzyl alcohol, tetrahydrofurfuryl alcohol, dioxane, dialkyl ketones having 3 to 5 carbon atoms, cyclohexane and lower alkyl esters of formic acid and acetic acid.

16. The method of claim 15 wherein the amount of said oxygen-containing compound is 3 to 35% by weight based on the total weight of the dye liquor, and the amount of said amide compound is 3 to 10% by weight based on the total amount of the dye liquor.

17. The method of claim 1 wherein said dye liquor further contains both (i) at least one metal sulfate and (ii) at least one oxygen-containing compound selected from the group consisting of alkanols having 3 to 5 carbon atoms, benzyl alcohol, tetrahydrofurfuryl alcohol, dioxane, dialkyl ketones having 3 to 5 carbon atoms, cyclohexanone and lower alkyl esters of formic acid and acetic acid.

18. The method of claim 17 wherein the total amount of said metal sulfate and the oxygen-containing compound is 3 to 35% by weight based on the total weight of the dye liquor, and the amount of said amide compound is 3 to 10% by weight based on the total amount of the dye liquor.

19. The method for coloring fibers or fibrous structures composed of phenolic resins, which comprises coloring said fibers of firbous structures using a dye liquor which contains, as a dye assistant, N,N-dimethyl formamide and benzyl alochol.

20. The method of claim 15 wherein said dye liquor is a printing paste containing dye.

21. The method of claim 17 wherein said dye liquor is a printing paste containing a dye.

22. The method of claim 20 wherein dyeing is carried out by printing method by applying said paste-like dye liquor to the phenolic fibers or fibrous structures, and then steaming them at 110.degree. to 140.degree.C. for 10 to 60 minutes.

23. The method of claim 21 wherein dyeing is carried out by printing method by applying said paste-like dye liquor to the phenolic fibers or fibrous structures, and then steaming them at 110.degree. to 140.degree.C. for 10 to 60 minutes.