PRODUCTION METHOD OF A HIGH-STRENGTH TEXTILE MATERIAL IN WHICH RAW MATERIAL STRESS IS ELIMINATED AND THIS MATERIAL

Abstract

Disclosed is a high-strength polyacrylate textile material and the production method for the said material, which includes the process of eliminating the stress in the raw material (polyacrylonitrile-based textile material) before the crosslinking, hydrolysis, acid and salt processes without allowing the material to physically shrink, so that the amount of shrinkage in crosslinking, hydrolysis, acid and salt processes decreases spontaneously.

Claims

1. A production method for high-strength polyacrylate textile material comprising the process steps of: i. Crosslinking of the polyacrylonitrile-based textile material used as raw material; ii. hydrolyzing the said crosslinked polyacrylonitrile-based textile material to obtain the polyacrylate textile material; wherein the amount of shrinkage in the crosslinking and hydrolyzing processes decreases spontaneously without being physically limited, eliminating the stress in the raw material (polyacrylonitrile-based textile material) before said processes without allowing the material to physically shrink.

2. The production method for high-strength polyacrylate textile material according to claim 1, wherein the shrinkage tendency is reduced by eliminating the stress in the raw material before the processing step i) or the processing step ii) or both processing steps.

3. The production method for high-strength polyacrylate textile material according to claim 1, further comprising; the process step (iii) wherein the polyacrylate textile material obtained after the processing step ii) is subjected to an acid treatment.

4. The production method for high-strength polyacrylate textile material according to claim 2, comprising; the process step (iv) for the treatment of said acid-treated polyacrylate textile material with metal salts.

5. The production method for high-strength polyacrylate textile material according to claim 1, wherein the stress in the raw material is eliminated by treating it with a substance without allowing the material to physically shrink at a temperature of 80 C. or above, thus reducing shrinkage tendency.

6. The production method for high-strength polyacrylate textile material according to claim 5, wherein the substance is a hot solid surface, a hot liquid, or a hot gas.

7. The production method for high-strength polyacrylate textile material according to claim 6, wherein the substance is hot metal roll surfaces.

8. The production method for high-strength polyacrylate textile material according to claim 6, wherein the substance is hot water or other liquids that are suitable for the purpose.

9. The production method for high-strength polyacrylate textile material according to claim 6, wherein the substance is water vapor, hot air, or other gases suitable for the purpose.

10. The production method for high-strength polyacrylate textile material according to claim 1, wherein the elimination of stress in the raw material is carried out under atmospheric conditions, under pressure, under vacuum or a combination thereof.

11. The production method for high-strength polyacrylate textile material according to claim 1, wherein at process step i), the reduction of shrinkage tendency is carried out by annealing in a pressurized autoclave without allowing the product to physically shrink.

12. The production method for high-strength polyacrylate textile material according to claim 1, wherein the polyacrylonitrile-based textile material is acrylic fiber or its semi-finished products or waste thereof.

13. The production method for high-strength polyacrylate textile material according to claim 1, wherein the polyacrylonitrile-based textile material is acrylic yarn or its semi-finished products or waste thereof.

14. The production method for high-strength polyacrylate textile material according to claim 1 wherein the polyacrylonitrile-based textile material is acrylic fabric or its semi-finished products or waste thereof.

15. A high-strength polyacrylate fiber obtained by the production method of a high-strength polyacrylate textile material according to claim 1. preceding claims.

16. A high-strength polyacrylate yarn obtained by the production method of a high-strength polyacrylate textile material according to claim 1.

17. A high-strength polyacrylate fabric obtained by the production method of a high-strength polyacrylate textile material according to claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0048] In this detailed description, preferred embodiments of the method of manufacturing the polyacrylate textile material, which is the subject of the invention, are described only for a better understanding of the subject matter.

[0049] Artificial textile fibers are basically produced by two different fiber extrusion methods: fiber extrusion from melt and fiber extrusion from solution. In order to make fiber extrusion, the polymer used as raw material is converted into a fluid structure with a viscosity suitable for fiber extrusion. The polymer used for this purpose is either melted or dissolved in a suitable solvent. The viscous polymer, which becomes suitable for fiber extrusion, is passed through perforated spinnerets and thus produced as endless filaments. Fiber is obtained by re-solidifying the filaments coming out of the spinnerets. In the melt fiber extrusion method, solidification is achieved by cooling. In the method of fiber extrusion from solution, solidification is achieved by volatilizing the solvent with an inert gas (dry fiber extrusion) or by washing with a nonsolvent (e.g. water) and replacing the solvent with the nonsolvent (wet fiber extrusion).

[0050] Polyacrylonitrile (acrylic) fiber, which is an example of a polyacrylonitrile-based textile material, is obtained by wet or dry fiber extrusion methods. In the production method of these polyacrylonitrile fibers; polyacrylonitrile polymer, which is generally used as a copolymer, is made into a solution with a suitable solvent (specifically preferably DMF, DMAc or DMSO) and this polymer solution is passed through perforated spinnerets and produced as endless filaments. The solvent in the fiber is replaced with water by washing with water and then the water in the fiber is removed using a drying system. In addition to the method mentioned above, the solvent in the fiber can be volatilized with inert gas, allowing the fiber to pass into the solid phase. During the process, the fibers are stretched (drawing process). By means of this drawing process, the polymer chains become oriented (parallel) at a certain level. In this way, the polymer chains can approach each other and form bonds between them called secondary attraction forces. These bonds are one of the most important factors determining fiber strength. As the orientation increases, more and stronger bonds are formed, which increase fiber strength.

[0051] Polyacrylate fibers, which are examples of polyacrylate textile materials, can be obtained by chemical modification of polyacrylonitrile fibers. Basically, polyacrylonitrile fibers can be converted into polyacrylate fibers by subjecting them to four different reactions (process steps). However, due to the radical shrinkage of polyacrylonitrile fibers during the mentioned processes, the orientation of the polymer chains is disrupted and accordingly, the polymer chains cannot form bonds between each other with sufficient efficiency in terms of quantity and quality, leading to loss of strength. The obtained polyacrylate fibers are not suitable for use in textile processes and textile products due to their low strength. Accordingly, with the present invention, a high-strength polyacrylate textile material and a method of producing this polyacrylate textile material are developed.

[0052] The method of producing a high-strength polyacrylate textile material developed by the present invention comprises the steps of; crosslinking of the polyacrylonitrile-based textile material used as raw material; hydrolyzing said crosslinked polyacrylonitrile-based textile material to obtain polyacrylate textile material; treating the obtained polyacrylate textile material with acid; treating said acid-treated polyacrylate textile material with metal salts. In the developed production method; [0053] the shrinkage of the polyacrylonitrile-based textile material fed as raw material to the mentioned processes is reduced without physically allowing the material to shrink before the mentioned processes, and thus the shrinkage of the material during the mentioned processes decreases spontaneously without physically limiting the shrinkage of the material.

[0054] In one embodiment of the method of the invention, the shrinkage tendency of the polyacrylonitrile-based textile material fed as raw material to the said processes is reduced before the crosslinking step, and thus the shrinkage of the material is automatically reduced during the aforementioned processes.

[0055] In one embodiment of the method of the invention, the shrinkage tendency of the polyacrylonitrile-based textile material fed as raw material to the said processes is reduced before the hydrolysis step, and thus the shrinkage of the material is automatically reduced during the aforementioned processes.

[0056] In one embodiment of the method of the invention, the shrinkage tendency of the polyacrylonitrile-based textile material fed as raw material to the said processes is reduced before both the crosslinking and the hydrolysis steps, and thus the shrinkage of the material is automatically reduced during the aforementioned processes.

[0057] In one embodiment of the method of the invention, shrinkage tendency is reduced by eliminating the stress in the raw material, preferably by treating the material with a substance to aid heat transfer, preferably at a temperature above 80 C. without allowing the material to physically shrink. The said substance is solid (hot metal roll surfaces), liquid (hot water or other hot liquids suitable for the purpose) or gas (water vapor, hot air or other gases suitable for the purpose).

[0058] In one embodiment of the method of the invention, the process of eliminating the stress in the raw material is carried out under atmospheric conditions, under pressure, under vacuum or under conditions consisting of a combination thereof.

[0059] In an exemplary embodiment of the present invention, prior to the process steps mentioned above, the polyacrylonitrile-based textile material (e.g. acrylic fibers in tow form) is subjected to saturated steam treatment (annealing process) in a pressurized vessel (autoclave) in a form in which shrinkage is not possible (e.g. the form in which the beginning and end are fixed and the tow is wound layer by layer on a roller in the form of a bobbin, which will not be deformed by the shrinkage force). Since the polyacrylonitrile-based textile material is very strong at this stage, the tension caused by not allowing shrinkage does not cause rupture. Also, the fact that the process is carried out in the form of a coil in which the tow is wound layer by layer on a roller does not pose any problem due to the very good ability of the saturated steam in a pressurized vessel to penetrate into the material. The fact that the autoclave to be used for the process is a type B autoclave makes it even easier for the steam to penetrate into the material. In type B autoclaves, the air in the autoclave and the material is purged by vacuuming before the steam is introduced into the autoclave for better penetration of the steam into the material. Then, steam is introduced into the autoclave to allow the steam to penetrate into the material better. By means of the process mentioned above, the stress in the molecular structure that causes shrinkage is eliminated, the molecular structure is fixed and most importantly, the polymer chain orientation is maintained, as shrinkage is not allowed during the process. In the known technique, commercial polyacrylonitrile fibers produced for standard textile uses (carpet, knitwear, etc.) are also subjected to saturated steam treatment in a pressure vessel, also called annealing, after production. However, in this standard application of the annealing process, shrinkage of the material is not prevented, in fact it is especially desired. The reason for this is that, as a result of shrinkage, some properties such as increasing the dye uptake rate, which is important for the textile industry, are also provided to the material. For this reason, in the standard application of the annealing process, the polyacrylonitrile tow is subjected to autoclave by filling it freely into perforated boxes without any obstruction. As a result of this process, the material shrinks by approximately 30%, the polymer chain orientation is disrupted, the strength of the material decreases, but the elongation feature and dye uptake speed increase and shrinkage in subsequent hot-wet textile processes (since the stress in the material is eliminated) is prevented.

[0060] In the method of the invention, before the polyacrylating process, the polyacrylonitrile-based textile material is treated with saturated steam in a pressurized container (autoclave) in a form where shrinkage is not possible. With this process, the stress that causes shrinkage of the material in polyacrylating processes is eliminated by maintaining the polymer chain orientation. In this way, the amount of shrinkage of the material in the mentioned polyacrylating processes decreases spontaneously (without physically limiting the shrinkage) and the strength of the polyacrylate textile material obtained is increased significantly.

[0061] Different polyacrylate fiber samples obtained by the polyacrylate textile material production method developed by the present invention and the properties of these samples are given below. [0062] PAN1: Normal polyacrylonitrile fiber. Not annealed. [0063] PAN2: Polyacrylonitrile fiber obtained by free annealing of PAN1 in a type B autoclave at 2.1 bar at 134 C without preventing its shrinkage. [0064] PAN3: Polyacrylonitrile fiber obtained by annealing of PAN1 in a type B autoclave at 2.1 bar at 134 C without allowing its shrinkage. [0065] PA1: PAN1 converted into polyacrylate fiber using the following conditions. [0066] PA2: PAN2 converted into polyacrylate fiber using the following conditions. [0067] PA3: PAN3 converted into polyacrylate fiber using the following conditions.

TABLE-US-00001 Temperature ( C.) Period (min) Hydrazine reaction 105 180 NaOH Reaction 105 120 Acetic Acid Reaction 60 60 Zinc Acetate Reaction 105 90

EXAMPLE 1

[0068] PAN1 polyacrylonitrile fibers were converted into polyacrylate fibers in a fiber dyeing vessel using the following conditions and PA1 fibers were obtained, whose properties are given in the table below.

TABLE-US-00002 Temperature ( C.) Period (min) Hydrazine reaction 105 180 NaOH Reaction 105 120 Acetic Acid Reaction 60 60 Zinc Acetate Reaction 105 90

TABLE-US-00003 Linear density 3.95 dtex Strength 10.27 cN/tex Elongation 50.15%

EXAMPLE 2

[0069] PAN2 polyacrylonitrile fibers were converted into polyacrylate fibers in a fiber dyeing vessel using the following conditions and PA2 fibers were obtained, whose properties are given in the table below.

TABLE-US-00004 Temperature ( C.) Period (min) Hydrazine reaction 105 180 NaOH Reaction 105 120 Acetic Acid Reaction 60 60 Zinc Acetate Reaction 105 90

TABLE-US-00005 Linear density 3.82 dtex Strength 9.73 cN/tex Elongation 47.21%

EXAMPLE 3

[0070] PAN3 polyacrylonitrile fibers were converted into polyacrylate fibers in a fiber dyeing vessel using the following conditions and PA3 fibers were obtained, whose properties are given in the table below.

TABLE-US-00006 Temperature ( C.) Period (min) Hydrazine reaction 105 180 NaOH Reaction 105 120 Acetic Acid Reaction 60 60 Zinc Acetate Reaction 105 90

TABLE-US-00007 Linear density 2.72 dtex Strength 23.38 cN/tex Elongation 29.83%