Black lyocell fibers, process for their production and use

Abstract

The present application relates to a kind of black lyocell fibers and its preparation method and application, the preparation method includes spinning solution preparation, spinning, solidification and post-processing, wherein, the solidification includes the following steps: the fiber stream obtained by spinning is formed into preliminary solidification into first coagulation bath, wherein, the first coagulation bath includes N-methyl morpholine and pyrrole monomer;Then the preliminary formed fiber is formed into solidification into second coagulation bath, wherein, the second coagulation bath includes N-methyl morpholine and the oxidizing polymerization agent of pyrrole.The preparation method of the present application utilizes the principle of pyrrole monomer polymerization reaction discoloration, based on two-stage coagulation bath treatment simultaneously completes black dyeing in the process of fiber solidification forming, not only dyeing fastness is good, and with the advantages of environmental protection, high efficiency, simplifying downstream dyeing and finishing process etc..

Description

Technical Field

[0001] This invention relates to the field of textile technology, and in particular to black lyocell fiber, its preparation method, and its applications. Background Technology

[0002] Lyocell fiber is a new type of environmentally friendly cellulose fiber product prepared by solution spinning. The preparation process includes steps such as spinning solution preparation, spinning, curing and post-treatment. Specifically, cellulose (pulp) is directly dissolved in an organic solvent / water system to prepare a spinning solution with a suitable concentration. The spinning solution is then extruded through a spinneret to form a fiber stream. The fiber stream enters a coagulation bath to solidify and shape. Finally, the finished fiber is obtained through post-treatment processes such as washing, oiling and drying.

[0003] In addition, current dyeing methods for cellulose fibers (including lyocell) are mainly concentrated at the downstream yarn or fabric end, generally using immersion dyeing or pad dyeing. Among them, the black dyes used for black cellulose fibers generally include direct dyes (such as Direct Black ECK, Direct Black 19, etc., which have good water solubility but relatively poor color fastness), reactive dyes (such as Jacobson TMGE reactive dyes, which contain reactive groups and have good color fastness, but the dyeing process is relatively complex), and sulfur dyes (such as environmentally friendly sulfur dyes, which have low cost, but generate sulfur-containing wastewater during dyeing). Summary of the Invention

[0004] Based on this, it is necessary to provide a black lyocell fiber, its preparation method, and its application to address the above problems. The preparation method utilizes the principle of color change through the polymerization reaction of pyrrole monomers and simultaneously completes black dyeing during the fiber solidification and molding process based on a two-stage coagulation bath treatment. This method not only has good color fastness but also has advantages such as being environmentally friendly, efficient, and simplifying downstream dyeing and finishing processes.

[0005] A method for preparing black lyocell fiber includes spinning solution preparation, spinning, curing, and post-treatment, wherein the curing includes the following steps:

[0006] The filaments obtained from spinning are introduced into a first coagulation bath for preliminary solidification and shaping. The first coagulation bath includes N-methylmorpholine oxide and pyrrole monomer.

[0007] The initially formed fibers are then placed in a second coagulation bath to solidify and solidify, wherein the second coagulation bath includes an oxidative polymerizing agent of N-methylmorpholine and pyrrole.

[0008] In one embodiment, the oxidative polymerizer of the pyrrole is selected from ferric chloride.

[0009] In one embodiment, the mass fraction of pyrrole monomer in the first coagulation bath is 1% to 5%;

[0010] And / or, the mass fraction of the pyrrole oxidizing agent in the second coagulation bath is 0.1% to 1%.

[0011] In one embodiment, the mass fraction of N-methylmorpholine in the first coagulation bath is greater than the mass fraction of N-methylmorpholine in the second coagulation bath.

[0012] In one embodiment, the mass fraction of N-methylmorpholine in the first coagulation bath is 10% to 20%;

[0013] And / or, the mass fraction of N-methylmorpholine in the second coagulation bath is 5% to 10%.

[0014] In one embodiment, the temperature of the first coagulation bath is greater than the temperature of the second coagulation bath;

[0015] And / or, the time for the fiber stream to enter the first coagulation bath for initial solidification is longer than the time for the initially formed fiber to enter the second coagulation bath for solidification.

[0016] In one embodiment, the temperature of the first coagulation bath is 8°C to 15°C;

[0017] And / or, the temperature of the second coagulation bath is 3℃~8℃.

[0018] In one embodiment, the time for the fiber stream to enter the first coagulation bath and initially solidify is 5 min to 10 min;

[0019] And / or, the time for the initially formed fibers to be solidified in the second coagulation bath is 3 to 5 minutes.

[0020] A black lyocell fiber obtained using the preparation method described above.

[0021] A textile made from the aforementioned black lyocell fiber.

[0022] In the preparation method of this invention, during the initial solidification and molding process of the spun fiber stream entering the first coagulation bath, the solvent in the fiber stream and the pyrrole monomer in the first coagulation bath will diffuse bidirectionally using the concentration gradient, allowing the pyrrole monomer to enter the fiber interior. Then, during the solidification and molding process of the initially solidified fiber entering the second coagulation bath, the pyrrole monomer in the fiber will undergo an in-situ polymerization reaction under the action of an oxidizing polymerizer, generating a black polymer in-situ inside the fiber. Thus, black dyeing is completed simultaneously during the fiber solidification and molding process, which not only has good color fastness, but also has the advantages of being environmentally friendly, efficient, and simplifying downstream dyeing and finishing processes. Detailed Implementation

[0023] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0025] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0026] The method for preparing black lyocell fiber provided by the present invention includes spinning solution preparation, spinning, curing and post-treatment.

[0027] In the preparation of the spinning solution, pulp is directly dissolved in an aqueous solution of N-methylmorpholine oxide (NMMO) to obtain the spinning solution. Optionally, the pulp is selected from at least one of bamboo pulp, recycled waste paper pulp, straw pulp, cotton fiber, and agricultural and forestry waste fiber. During preparation, an aqueous solution of N-methylmorpholine oxide with a mass fraction of 86% to 88% is first heated to 100°C to 110°C. Then, the pulp is pulverized and mixed with the N-methylmorpholine oxide aqueous solution at a mass ratio of 1:10 to 1.2:10. The temperature is further increased to 110°C to 120°C until the pulp is completely dissolved, resulting in a homogeneous and stable spinning solution.

[0028] Then, the spinning solution is extruded through the spinneret to form a fine stream of fibers, which enters the coagulation bath to solidify and take shape.

[0029] In this invention, the spun fiber stream first enters a first coagulation bath for preliminary solidification and shaping, and then the preliminarily shaped fiber enters a second coagulation bath for further solidification and shaping. The first coagulation bath includes N-methylmorpholine oxide and pyrrole monomers, and the second coagulation bath includes an oxidative polymerizing agent of N-methylmorpholine oxide and pyrrole.

[0030] Therefore, during the initial solidification process of the fiber stream obtained by spinning in the present invention, the solvent in the fiber stream and the pyrrole monomer in the first solidification bath will diffuse bidirectionally using the concentration gradient, allowing the pyrrole monomer to enter the fiber interior. Then, during the solidification process of the initially solidified fiber in the second solidification bath, the pyrrole monomer in the fiber will undergo an in-situ polymerization reaction under the action of the oxidizing polymerizing agent, generating a black polymer in situ inside the fiber. Thus, black dyeing is completed simultaneously during the fiber solidification process, which not only has good color fastness, but also has the advantages of being environmentally friendly, efficient, and simplifying downstream dyeing and finishing processes.

[0031] Optionally, the oxidative polymerizing agent for the pyrrole is selected from ferric chloride (FeCl3).

[0032] Optionally, the mass fraction of pyrrole monomer in the first coagulation bath is 1% to 5%, such as 1%, 2%, 3%, 4%, 5%, etc., and the mass fraction of pyrrole oxidizing polymer in the second coagulation bath is 0.1% to 1%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc.

[0033] Optionally, the mass fraction of N-methylmorpholine in the first coagulation bath is greater than the mass fraction of N-methylmorpholine in the second coagulation bath. Preferably, the mass fraction of N-methylmorpholine in the first coagulation bath is 10% to 20%, such as 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc., and the mass fraction of N-methylmorpholine in the second coagulation bath is 5% to 10%, such as 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0034] Optionally, the temperature of the first coagulation bath is higher than the temperature of the second coagulation bath. Preferably, the temperature of the first coagulation bath is 8℃ to 15℃, such as 8℃, 9℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, etc., and the temperature of the second coagulation bath is 3℃ to 8℃, such as 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, etc.

[0035] Optionally, the time for the fiber stream to initially solidify in the first coagulation bath is longer than the time for the initially formed fiber to solidify in the second coagulation bath. Preferably, the time for the fiber stream to initially solidify in the first coagulation bath is 5 min to 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc., and the time for the initially formed fiber to solidify in the second coagulation bath is 3 min to 5 min, such as 3 min, 4 min, 5 min, etc.

[0036] Thus, enough pyrrole monomers can enter the fiber and polymerize into a black polymer, completing the fiber dyeing process.

[0037] After curing, the fibers undergo post-treatment to obtain black lyocell fibers. The post-treatment process involves washing with water to precipitate N-methylmorpholine oxide from the fibers and removing residual ferric chloride and unreacted pyrrole from the fiber surface. Subsequently, the fibers undergo oiling, drying, and other processes to obtain the finished fibers.

[0038] Furthermore, the present invention also provides a black lyocell fiber obtained by the preparation method described above, wherein the black lyocell fiber has good color fastness.

[0039] Furthermore, the present invention also provides a textile made of the aforementioned black lyocell fiber.

[0040] The following specific embodiments will further illustrate the black lyocell fiber, its preparation method, and its application.

[0041] Example 1

[0042] An 87% N-methylmorpholine aqueous solution was injected into a dissolving vessel, heated, and maintained at 100°C to form a stable solution. Then, pulverized cotton fibers were added to the dissolving vessel, with a cotton fiber to N-methylmorpholine aqueous solution mass ratio of 1:10. The temperature was further increased to 110°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0043] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 15%, the mass fraction of pyrrole monomer is 3%, the temperature of the first coagulation bath is 8℃, and the preliminary solidification time is 5 minutes.

[0044] The initially formed fibers are then transferred to the second coagulation bath via guide rollers to solidify and form. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 5%, the mass fraction of ferric chloride in the second coagulation bath is 0.5%, the temperature of the second coagulation bath is 3°C, and the solidification time is 3 minutes.

[0045] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0046] Example 2

[0047] An 86% N-methylmorpholine aqueous solution was injected into a dissolving vessel, and the temperature was raised and maintained at 105°C to form a stable solution. Then, pulverized cotton fibers were added to the dissolving vessel, with a cotton fiber to N-methylmorpholine aqueous solution mass ratio of 1.1:10. The temperature was further raised to 115°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0048] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 10%, the mass fraction of pyrrole monomer is 1%, the temperature of the first coagulation bath is 10℃, and the preliminary solidification time is 6 minutes.

[0049] The initially formed fibers are then transferred to the second coagulation bath via guide rollers to solidify and form. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 6%, the mass fraction of ferric chloride in the second coagulation bath is 0.1%, the temperature of the second coagulation bath is 4℃, and the solidification time is 4 minutes.

[0050] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0051] Example 3

[0052] An 87% N-methylmorpholine aqueous solution was injected into a dissolving vessel, and the temperature was raised and maintained at 110°C to form a stable solution. Then, bamboo pulp was added to the dissolving vessel, with a mass ratio of bamboo pulp to N-methylmorpholine aqueous solution of 1:10. The temperature was further raised to 120°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0053] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 12%, and the mass fraction of pyrrole monomer is 4%. The temperature of the first coagulation bath is 12℃, and the preliminary solidification time is 7 minutes.

[0054] The initially formed fibers are then transferred by guide rollers to the second coagulation bath for solidification. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 8%, the mass fraction of ferric chloride in the second coagulation bath is 0.3%, the temperature of the second coagulation bath is 6°C, and the solidification time is 4 minutes.

[0055] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0056] Example 4

[0057] An 88% N-methylmorpholine aqueous solution was injected into a dissolving vessel, heated, and maintained at 100°C to form a stable solution. Bamboo pulp was then added to the dissolving vessel, with a mass ratio of bamboo pulp to N-methylmorpholine aqueous solution of 1.2:10. The temperature was further increased to 110°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0058] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 20%, and the mass fraction of pyrrole monomer is 5%. The temperature of the first coagulation bath is 15℃, and the preliminary solidification time is 5 minutes.

[0059] The initially formed fibers are then transferred to the second coagulation bath via guide rollers to solidify and form. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 10%, the mass fraction of ferric chloride in the second coagulation bath is 1%, the temperature of the second coagulation bath is 8°C, and the solidification time is 3 minutes.

[0060] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0061] Example 5

[0062] An 88% N-methylmorpholine aqueous solution was injected into a dissolving vessel, and the temperature was raised and maintained at 105°C to form a stable solution. Then, recycled waste paper pulp was added to the dissolving vessel, with a mass ratio of recycled waste paper pulp to N-methylmorpholine aqueous solution of 1:10. The temperature was further raised to 120°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0063] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 15%, the mass fraction of pyrrole monomer is 2%, the temperature of the first coagulation bath is 10℃, and the preliminary solidification time is 10 minutes.

[0064] The initially formed fibers are then transferred to the second coagulation bath via guide rollers to solidify and form. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 5%, the mass fraction of ferric chloride in the second coagulation bath is 0.2%, the temperature of the second coagulation bath is 5°C, and the solidification time is 5 minutes.

[0065] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0066] Example 6

[0067] An 87% N-methylmorpholine aqueous solution was injected into a dissolving vessel, heated, and maintained at 100°C to form a stable solution. Then, straw pulp was added to the dissolving vessel, with a straw pulp to N-methylmorpholine aqueous solution mass ratio of 1.1:10. The temperature was further increased to 115°C, and mechanical stirring was maintained in the dissolving vessel until the pulp was completely dissolved, forming a homogeneous and stable spinning solution.

[0068] The spinning solution is extruded through a spinneret via a conveying screw and a metering pump, and under pressure, it is extruded through the spinneret orifices to form a fine fiber stream, which then enters the first coagulation bath for preliminary solidification. The first coagulation bath consists of N-methylmorpholine oxide, pyrrole monomer, and water. The mass fraction of N-methylmorpholine oxide in the first coagulation bath is 16%, and the mass fraction of pyrrole monomer is 4%. The temperature of the first coagulation bath is 12℃, and the preliminary solidification time is 6 minutes.

[0069] The initially formed fibers are then transferred to the second coagulation bath via guide rollers to solidify and form. The second coagulation bath consists of N-methylmorpholine oxide, ferric chloride, and water. The mass fraction of N-methylmorpholine oxide in the second coagulation bath is 8%, the mass fraction of ferric chloride in the second coagulation bath is 0.8%, the temperature of the second coagulation bath is 5°C, and the solidification time is 4 minutes.

[0070] The solidified fiber is drawn away from the second coagulation bath by a drawing roller. A nozzle connected to a soft water pipe is installed above the drawing roller to spray the fiber from top to bottom. Then, black lyocell fiber is obtained through processes such as cutting, oiling, drying, opening, and packaging.

[0071] The black lyocell fibers obtained in Examples 1-6 were tested for performance according to "GB / T 3921-2008 Textiles - Tests for Color Fastness to Soap Washing". The results are shown in Table 1.

[0072] Table 1

[0073]

[0074]

[0075] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing black lyocell fiber, comprising spinning solution preparation, spinning, curing, and post-treatment, characterized in that, The curing process includes the following steps: The filaments obtained from spinning are introduced into a first coagulation bath for preliminary solidification and shaping. The first coagulation bath includes N-methylmorpholine oxide and pyrrole monomer. The initially formed fibers then enter a second coagulation bath to solidify and solidify, wherein the second coagulation bath includes an oxidative polymerizing agent of N-methylmorpholine oxide and pyrrole; The mass fraction of N-methylmorpholine in the first coagulation bath is greater than that in the second coagulation bath, wherein the mass fraction of N-methylmorpholine in the first coagulation bath is 10%~20% and the mass fraction of N-methylmorpholine in the second coagulation bath is 5%~10%. The temperature of the first coagulation bath is higher than the temperature of the second coagulation bath. The temperature of the first coagulation bath is 8℃~15℃, and the temperature of the second coagulation bath is 3℃~8℃. The time for the fiber stream to initially solidify in the first coagulation bath is longer than the time for the initially formed fiber to solidify in the second coagulation bath. The initial solidification time for the fiber stream in the first coagulation bath is 5 min to 10 min, and the time for the initially formed fiber to solidify in the second coagulation bath is 3 min to 5 min.

2. The method for preparing black lyocell fiber according to claim 1, characterized in that, The oxidative polymerizing agent for the pyrrole is selected from ferric chloride.

3. The method for preparing black lyocell fiber according to claim 1, characterized in that, The mass fraction of pyrrole monomer in the first coagulation bath is 1%~5%; And / or, the mass fraction of the pyrrole oxidizing agent in the second coagulation bath is 0.1% to 1%.

4. A black lyocell fiber obtained by the preparation method according to any one of claims 1 to 3.

5. A textile made from the black lyocell fiber as described in claim 4.

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