Low VOC ionic solvents as dye supports for aramid fibers

Abstract

Compositions and methods for dyeing aromatic polyamides include one or more dye supports selected from dialkyl imidazolium salts of cations having the general formula: # imgabs 0 # wherein R1 and R2 are independently selected from C1 to C8 alkyl groups, and biquaternary ammonium salts of cations having the formula: # imgabs 1 # wherein R1 is independently in each case C1 to C6 alkyl groups; r2 and R3 are independently in each case a C1-C6 alkyl group or a substituted C1-C6 alkyl group, and X is independently in each case a halogen; and one or more cationic dyes.

Description

Technical Field

[0001] Embodiments are directed to non-volatile dye carriers for dyeing and processing aramids, and methods of dyeing aramid fibers and textiles.

[0002] introduction

[0003] Aromatic polyamide (aramid) in fiber form produces durable, highly chemically resistant and stable (fireproof) textile materials and products at high temperatures. Compared with typical textiles, aromatic polyamides are hydrophobic and difficult to dye because standard aqueous dye preparations cannot penetrate into the material. In a typical aromatic polyamide fiber dyeing operation, aromatic polyamide textiles and fibers are treated with an aqueous dye solution containing a dye carrier that swells the constituent fibers in a pressurized dyeing apparatus. The dye carrier facilitates the penetration of the dye into the entire aromatic polyamide fiber and enhances color and color retention. Solvents such as acetophenone were once prevalent in industrial processes as dye carriers, but high vapor pressures and concerns about odor and toxicity have led to interest in alternatives that reduce volatile organic compound (VOC) emissions. Summary of the invention

[0004] The composition for dyeing aromatic polyamide comprises: one or more dye carriers selected from cationic dialkyl imidazolium salts having the following general formula:

[0005]

[0006] wherein R1 and R2 are independently selected from C1 to C8 alkyl, and a diquaternary ammonium salt of a cation having the formula:

[0007]

[0008] wherein R1 is independently C1-C6 alkyl at each occurrence; R2 and R3 are independently C1-C6 alkyl or substituted C1-C6 alkyl at each occurrence, and X is independently halogen at each occurrence; and one or more cationic dyes. DETAILED DESCRIPTION

[0009] Embodiments relate to dyeing preparations containing dye carrier compositions and methods for dyeing aramid fibers and articles, particularly meta-aramids. The dye carrier compositions disclosed herein can be non-volatile, have low or negligible vapor pressures at room temperature and correspondingly negligible VOC emissions, and include one or more ionic liquids and / or diquaternary ammonium salts. The methods for dyeing aramid fibers and articles can include contacting the fibers or articles with a dye preparation containing one or more dye carriers.

[0010] As used herein, "aramid" refers to an aromatic polyamide having at least 85% amide bonds formed between aromatic rings, particularly aromatic polyamides such as poly(m-phenylene isophthalamide) and poly(p-phenylene terephthalamide). Aramids may include commercially available materials formed by the reaction of m-phenylene diamine and isophthaloyl chloride, such as NOMEX®, produced by DuPont and Teijin, respectively. TM and CONEX TM .

[0011] Dye preparation can comprise one or more in each in cationic dye, solvent, dye carrier and various additives.Cationic dye comprises any dye applicable to aromatic polyamide, comprises phenoxazine dye, such as phenoxazine-5-ium, 3,7-bis (diethylamino)-chlorine, azo dye, triarylmethane dye, anthraquinone dye, azamethine (azamethine) dye, triazole azo dye, thiazole azo dye, benzothiazole azo dye, triphenylmethane dye etc.Dye preparation solvent used comprises aqueous fluid, salt or saline solution, buffer, alcohol-water mixture etc.Dye preparation can comprise one or more cationic dyes of any suitable concentration, such as weight percentage (weight %) in the range of 1 weight % to 10 weight %, 2 weight % to 10 weight % or 2 weight % to 8 weight %.

[0012] The dye preparation disclosed herein may include one or more dye carriers, such as dialkyl imidazolium salts or diquaternary ammonium salts. The dialkyl imidazolium salt may include a salt of a cation having the general formula:

[0013]

[0014] wherein R1 and R2 are independently selected from C1 to C8 alkyl. The imidazolium salts disclosed herein may include 1,3 dialkyl imidazolium salts having a dialkyl imidazolium cation, such as 1,3-dimethyl imidazolium, 1-ethyl-3-methyl imidazolium, 1-butyl-3-methyl imidazolium, 1-butyl-2,3 dimethyl imidazolium, 1-ethyl-3-methyl imidazolium, 1-octyl-3-methyl imidazolium, 1-ethyl-3-methyl imidazolium, 1-butyl-3-methyl imidazolium, 1-octyl-3-methyl imidazolium salts, 1-ethyl-3-methyl imidazolium, 1-butyl-3-methyl imidazolium, 1-octyl ...

[0015] -imidazolium, 1-allyl-3-methylimidazolium, etc. The anion component of the imidazolium salt can be a halide ion such as chloride, bromide, iodide, etc., or a C1 to C6 carboxylate such as formate, acetate, propionate, etc. Examples of dialkyl imidazolium salts include 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium propionate, 1-methyl-3-methylimidazolium formate and 1-propyl-3-methylimidazolium formate, and 1-allyl-3-methylimidazolium chloride, etc.

[0016] The dye carrier may include a diquaternary ammonium salt having a cation of the formula:

[0017]

[0018] wherein R1 is independently C1-C6 alkyl at each occurrence; R2 and R3 are independently C1-C6 alkyl or substituted C1-C6 alkyl at each occurrence, and X is independently halogen at each occurrence, such as Cl, Br or I. Suitable diquaternary ammonium salts include, for example, N,N"-(oxybis(ethane-2,1-diyl)-bis(3-chloro-2-hydroxy-N,N-dimethylpropan-1-ammonium)

[0019] chloride.

[0020] Dye preparation can include by weight percentage (wt%) in the range of 1 wt % to 10 wt %, 2 wt % to 8 wt % or 2 wt % to 6 wt % One or more dye carriers. One or more dye carriers can also be combined with 1-phenoxy-2-propanol (PPh) with the weight percentage (wt %) in the range of 1 wt % to 10 wt %, 2 wt % to 8 wt % or 2 wt % to 5 wt %, or the weight ratio of 2:1 to 1:2 or 1.5:1 to 1:1.5. Dye preparation can have the pH in the range of pH 5 to pH 13, pH 6 to pH 12.5 or pH 6.5 to pH 12. When dye preparation includes PPh, pH can be lower, such as in the range of pH 2.5 to pH 5, pH 2.5 to pH 4 or pH 3 to pH 4. In one example, the dye formulation may include 3 wt% to 6 wt% of one or more dye carriers, 0 wt% to 6 wt% PPh, and a pH ranging from 2.5 to 12.5.

[0021] The dye formulation may include one or more additives, such as materials for pH adjustment, including organic acids, inorganic acids, inorganic salts such as sodium nitrate or sodium chloride, emulsifiers, surfactants such as anionic surfactants, UV light absorbers, pH adjusters such as buffers, acids or bases, processing aids, etc.

[0022] The method of applying a dye to aramid fibers may include preparing a dye solution having a dye carrier, dosing and adjusting the pH, contacting an aramid fiber sample with the dye solution, dyeing the aramid fibers at a selected temperature, rinsing excess dye from the dyed aramid fibers, and drying the fiber sample.

[0023] During application of the dye formulation (e.g., when contacting the aramid fibers or articles), the temperature of the mixture may be in the range of 120°C to 170°C, 130°C to 160°C, or 130°C to 150°C. The contacting may be carried out in any suitable dyeing equipment, including pressurized or non-pressurized vessels. In some cases, the aramid fibers and articles may be wound through an internal rotating assembly and circulated through the dye formulation during the dyeing operation. Dyeing times may vary depending on a variety of factors such as sample size, temperature, dye or dye carrier concentration, etc., but may generally vary from 30 minutes to an hour or more. Color values ​​may be obtained using Hunterlab TM Colorimeter quantification, including L, A and B color values.

[0024] Example

[0025] The following examples are provided to illustrate embodiments of the present invention and are not intended to limit the scope of the invention. Table 1 provides the materials used in the following examples.

[0026]

[0027] Example 1: Dyeing process of aramid fabric

[0028] In this example, aramid fabric samples were analyzed using various dye formulations. A 2 wt% solution of Basic Blue #3 was prepared by dissolving 2 g of dye in 98 g of deionized water.

[0029] Staining equipment and loading procedures

[0030] Dyed in Ahiba from Datacolor TM The dyeing process is carried out in an IR Pro Exhaust Dyeing chamber. The chamber accommodates up to 15 stainless steel 250 mL dyeing vessels in a rotating assembly and is capable of operating at up to 130°C.

[0031] Use 2” x 2” Samples were prepared and placed in numbered dyeing containers. 2.5 g of blue dye aqueous solution was charged to the container, followed by the desired weight of each individual component of the test dye bath (e.g., dye carrier and water) and adjusted to 50.0 g with water. The pH of each bath was adjusted with acid or base as required. The dyeing container was then sealed and placed in the numbered holder of the rotating assembly. Then the Ahiba TM The IR chamber was heated at the desired temperature for 50 minutes. After dye preparation treatment, the samples were cooled and washed with water to remove excess dye. The rinsed samples were dried in a 45°C oven.

[0032] Then use Hunterlab TM The colorimeter measures the L and b color values ​​of the samples. The colorimeter is calibrated using the D65-10 diffuse 8° white tile provided by the manufacturer. As a control sample, undyed NOMEX TM The sample was placed in the center of a 4.25 x 4.25 inch black tile equipped with a mask designed to help position and secure the sample to the tile. Several readings were taken and the results averaged. The undyed sample was replaced with a stained sample so that a color reading could be taken. The procedure was repeated with all samples. The sample preparation and color results are shown in Table 2.

[0033]

[0034]

[0035] The samples in the chart are indicated as "Nomex" for a control sample not exposed to a dye solution, "B" for a blank sample comprising a solution of dye and water without a dye carrier, "CS" for a comparative sample containing only PPh, or "IS" for a sample of the invention containing only a dialkylimidazolium or diquaternary ammonium dye carrier or in combination with PPh. The target property value for the sample is the minimum value of L or b relative to the Nomex and blank samples.

[0036] The samples were analyzed at pH ranging from lower pH (3.5, a typical dye pH for PPh) to higher pH (about 6.7-12.5) and at lower dyeing temperatures (70°C) and higher dyeing temperatures (130°C). The samples of the present invention generally performed as well as or better than the comparative formulations containing only PPh. Example 1 shows that the dye formulation of the present invention (IS) has been found to be generally superior to PPh at higher pH (6-12). It is worth noting that the combination of 2 wt% PPh and 2 wt% diquaternary ammonium salt (IS8) gave an L value of 39.7 and a b value of -16.7, superior to CS4 including 4 wt% PPh. In contrast, L values ​​of 43.4 to 46.2 were obtained by adding 3 wt%, 4 wt% or 6 wt% dialkyl imidazole salts to the dye bath in the pH range of 6.2 to 6.5 (IS10-IS12). Furthermore, an L value of 46.6 was obtained at pH 12.5 with 4% dialkyl imidazolium salt (IS13, b value -14.1). At a pH of 9.6 (IS14) or 6.7 (IS15), the addition of 4 wt% diquaternary ammonium salt to the dye bath produced an L value of about 55, while an increase to 6 wt% gave an L value of 29.3 and a b value of -19.7 (IS16).

[0037] While the foregoing is directed to illustrative embodiments, other and further embodiments may be devised without departing from the basic scope of the present invention, which is defined by the claims that follow.

Claims

1. A composition for dyeing aromatic polyamide, comprising: One or more dye carriers selected from Dialkyl imidazolium salts of cations having the general formula: wherein R1 and R2 are independently selected from C1 to C8 alkyl, and a diquaternary ammonium salt of a cation having the formula: wherein R1 is independently C1-C6 alkyl at each occurrence; R2 and R3 are independently C1-C6 alkyl or substituted C1-C6 alkyl at each occurrence, and X is independently halogen at each occurrence; and One or more cationic dyes.

2. The composition of claim 1, wherein the one or more dye carriers are present in a weight percentage ranging from 3 wt% to 6 wt%.

3. The composition of claim 1, wherein the composition comprises a pH in the range of pH 6 to pH 12.

5.

4. The composition according to claim 1, wherein the composition further comprises 1-phenoxy-2-propanol in a weight percentage of 2 wt% to 6 wt%.

5. The composition according to claim 4, wherein the pH is in the range of pH 2.5 to pH 4.

6. The composition of claim 1, wherein the one or more dye carriers comprise a diquaternary ammonium salt in an amount ranging from 2 wt% to 6 wt% of the composition, and the composition has a pH of 6 to 7.

7. A method comprising: The aromatic polyamide is contacted at a temperature in the range of 120°C to 160°C with a dye preparation comprising: One or more dye carriers selected from dialkyl imidazolium salts of cations having the general formula: wherein R1 and R2 are independently selected from C1 to C8 alkyl, and a diquaternary ammonium salt of a cation having the formula: wherein R1 is independently C1-C6 alkyl at each occurrence; R2 and R3 are independently C1-C6 alkyl or substituted C1-C6 alkyl at each occurrence, and X is independently halogen at each occurrence; and One or more cationic dyes.

8. The method of claim 7, wherein the temperature is in the range of 130°C to 140°C.

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