Preparation method of carbon fiber suitable for woven fabric

Abstract

The invention relates to a preparation method of carbon fibers suitable for woven fabrics, and belongs to the field of carbon fiber production. The preparation method comprises the following steps: polymerizing acrylonitrile and a comonomer in a dimethyl sulfoxide solution, separating the monomer, removing gas mixed in a polymerization solution, solidifying and forming into a solidified filament by adopting a wet or dry-wet spinning process, drafting, washing the solidified filament with water, drafting in hot water, oiling the washed and drafted solidified filament, and drying, thereby obtaining the high-strength and high-toughness polyester fiber. The preparation method comprises the following steps: preparing monofilaments, drying and densifying by using a hot roller, drafting the monofilaments by using saturated water vapor, carrying out heat setting on the fibers by using saturated water vapor, collecting the protofilaments to obtain the protofilaments, carrying out oxidation treatment on the protofilaments, carrying out low-temperature carbonization treatment on the pre-oxidized filaments, and carrying out high-temperature carbonization treatment on the filaments subjected to low-temperature carbonization treatment, constant current is applied to the filaments subjected to high-temperature carbonization treatment in an electrolytic solution for surface treatment, washing and sizing are conducted, then the filaments are dried, the dried fibers are subjected to secondary finishing, and the finished carbon fibers are obtained after the carbon fibers are wound.

Description

Technical Field

[0001] The invention relates to the field of carbon fiber production, in particular to a method for preparing carbon fiber suitable for woven fabrics. Background Art

[0002] As we all know, carbon fiber woven fabric is a commonly used weaving form. Woven fabrics are made of warp and weft yarns interwoven on the loom according to a certain pattern. There are many different weaving methods, including plain weave, twill and satin. The organization formed by the warp and weft yarns interwoven one above and one below is called plain weave; the organization in which the warp points (or weft points) are continuously diagonal is called twill weave; the organization in which the separate, discontinuous warp points (or weft points) are regularly and evenly distributed in the organization cycle is called satin weave. Carbon fiber warp knitted fabric keeps the carbon fiber straight, meets the requirements of the direction, proportion and sequence of the ply, and has good integrity and good paving properties. It is an ideal composite material reinforcement material. In order to meet the use requirements of woven fabrics, the appearance of carbon fiber, such as uniformity and flatness, is also put forward corresponding requirements in addition to its own performance indicators. Therefore, it is necessary to study the controllability of carbon fiber according to the needs. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a method for preparing carbon fibers suitable for woven fabrics, and produces carbon fibers that are beneficial to woven fabrics.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing carbon fiber suitable for woven fabrics, comprising the following steps: 1. Polymerization: acrylonitrile and comonomer are polymerized in dimethyl sulfoxide solution; 2. De-monomerization and degassing: Under vacuum conditions, the residual acrylonitrile monomer in the polymerization solution is separated from the system to separate the monomer; the mixed gas in the polymerization solution is removed to eliminate bubbles and obtain a stable spinning solution; 3. Coagulation: The spinning solution is output through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, and then enters the coagulation liquid to coagulate into coagulated filaments by wet or dry-wet spinning process; 4. Washing: Wash the coagulated filaments with water, using a roller beating method, and the direction of the water flow is countercurrent; 5. Hot water drawing: Apply tension to the washed silk in hot water and draw it 1.2 to 4 times; 6. Oiling and drying and densification: Use modified silicone oil or non-silicone oil to oil the coagulated filaments after washing and drawing, and use hot rollers to dry and densify; 7. Steam drawing: Use saturated steam to apply tension for 1.5 to 6 times drawing; 8. Heat setting: Use saturated steam to heat set the fiber; 9. Raw silk collection: Use a winding machine to collect the raw silk to obtain finished raw silk; 10. Pre-oxidation: Apply tension to the raw silk in an environment of 200-300°C for oxidation treatment; 11. Low temperature carbonization: The pre-oxidized wire strips are subjected to low temperature carbonization treatment at 300-800°C; 12. High temperature carbonization: The wire strips after low temperature carbonization are subjected to high temperature carbonization treatment at 1000-1600°C; 13. Surface treatment: Apply a constant current to the high-temperature carbonized wire in an electrolytic solution for surface treatment, and then wash it with water; 14. Sizing: Before sizing, the silk strips are first arranged to evenly arrange the fibers on the rollers. Each group of rollers includes ≥5 rollers. After being arranged by more than 2 groups of rollers, a fiber bundle with uniform wire width is formed, and then immersed in the sizing tank for sizing. After sizing, the silk strips are dried, and the dried fibers are arranged for the second time; 15. Carbon fiber winding: Use a winding machine to collect the carbon fiber to obtain finished carbon fiber.

[0005] In the polymerization step, the comonomer may be one or more of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

[0006] In the coagulation step, the tension is the tension after leaving the coagulation bath, ranging from 0.5 to 1.0 cN / dtex. Tension is applied to the coagulated filaments after leaving the coagulation bath and before entering the water washing to stretch the cross-sectional diameter of the single filament to 30 to 40 um.

[0007] In the water washing step, the water temperature of the water washing is controlled at 30-70°C, and the tension range of the tow during the water washing process is 1.0-3.5 cN / dtex.

[0008] In the hot water drawing step, the applied tension is 1.0-2.0 cN / dtex, and the cross-sectional diameter of the monofilament is drawn to 19-26 um.

[0009] In the oiling and drying and densification steps, the drying and densification temperature is 100-190°C.

[0010] In the steam drawing step, the applied tension is 0.5-1.0 cN / dtex, and the cross-sectional diameter of the monofilament is drawn to 9-12 um.

[0011] In the pre-oxidation step, the applied tension is 0.5-1.0 cN / dtex until the density is 1.35-1.40 g / cm 3 .

[0012] In the sizing step, the tension between the rollers is maintained at <0.5 cN / dtex.

[0013] The beneficial effect of the present invention is that, through the technological control of the carbon fiber production process, carbon fiber with less fuzz and good uniformity is formed, which is beneficial to the production of woven fabrics.

[0014] The present invention is further described below in conjunction with embodiments. DETAILED DESCRIPTION

[0015] The present invention mainly comprises the following steps according to the preparation of the raw silk: Polymerization: acrylonitrile and comonomers are polymerized in a dimethyl sulfoxide solution; demonstration and degassing: under vacuum conditions, the residual acrylonitrile monomer in the polymerization solution is separated from the system to separate the monomer; the mixed gas in the polymerization solution is removed to eliminate bubbles to obtain a stable spinning solution; coagulation and molding: the spinning solution is output through a spinning metering pump, flows through a buffer, enters the spinneret assembly and is ejected, and adopts a wet or dry-wet spinning process to enter the coagulation liquid to coagulate and mold into a coagulated filament. After the coagulated filament exits the coagulation bath and before entering the water washing, tension is applied to the coagulated filament to stretch the cross-sectional diameter of the single filament; washing: the coagulated filament is washed with water, and the washing is performed by a flower roller beating type washing, and the washing water flow direction is countercurrent; hot water drawing: tension is applied to the washed filament in hot water to stretch the cross-sectional diameter of the single filament; oiling and drying and densification: modified silicone oil or non-silicone oil agent is used to oil the coagulated filament after water washing and traction, and hot rollers are used for drying and densification; steam drawing: saturated Apply tension with water vapor for stretching, and stretch the cross-sectional diameter of the single fiber; heat setting: use saturated water vapor to heat set the fiber; raw silk collection: use a winding machine to collect the raw silk to obtain the finished raw silk; pre-oxidation: apply tension to the raw silk in an environment of 200-300°C for oxidation treatment; low-temperature carbonization: the pre-oxidized silk strips are subjected to low-temperature carbonization treatment at 300-800°C; high-temperature carbonization: the silk strips after low-temperature carbonization treatment are subjected to high-temperature carbonization treatment at 1000-1600°C; surface treatment: a constant current is applied to the silk strips after high-temperature carbonization treatment in an electrolytic solution for surface treatment, and then washed with water; sizing: the silk strips are first arranged before sizing, the fibers are evenly arranged on the rollers, and fiber bundles with uniform wire width are formed after arrangement, and then immersed in the sizing tank for sizing, and the silk strips are dried after sizing, and the fibers after drying are arranged for the second time; carbon fiber winding: the carbon fiber is collected by a winding machine to obtain finished carbon fiber.

[0016] Example 1 During the solidification process, the bath tension is 0.8 cN / dtex, and the cross-sectional diameter of the single fiber is stretched to 35um; the tension of the bundle during the water washing process is 2.5 cN / dtex; 3.0 times stretching is performed during the hot water stretching process; a tension of 1.5 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 22um; saturated water vapor is used for 4 times stretching during the steam stretching process; a tension of 0.8 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 10um; a tension of 0.8 cN / dtex is applied during the pre-oxidation process until the density is 1.36g / cm3; the filaments are first sorted before sizing, and the fibers are evenly arranged on the rollers. Each group of rollers includes 5 roller rollers, and the tension between the rollers is maintained at 0.2 cN / dtex. After being sorted by two groups of roller rollers, a fiber bundle with uniform wire width is formed, and then immersed in the sizing tank for sizing. After sizing, the filaments are dried, and the dried fibers are sorted for the second time.

[0017] Example 2 During the solidification process, the bath tension is 0.8 cN / dtex, and the cross-sectional diameter of the single fiber is stretched to 35um; the tension of the bundle during the water washing process is 2.5 cN / dtex; 3.0 times stretching is performed during the hot water stretching process; a tension of 1.5 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 22um; saturated water vapor is used for 4 times stretching during the steam stretching process; a tension of 0.8 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 10um; a tension of 0.8 cN / dtex is applied during the pre-oxidation process until the density is 1.36g / cm3; the filaments are first sorted before sizing, and the fibers are evenly arranged on the rollers. Each group of rollers includes 9 roller rollers, and the tension between the rollers is maintained at 0.2 cN / dtex. After being sorted by two groups of roller rollers, a fiber bundle with uniform wire width is formed, and then immersed in the sizing tank for sizing. After sizing, the filaments are dried, and the dried fibers are sorted for the second time.

[0018] Example 3 During the solidification process, the bath tension is 1.0 cN / dtex, and the cross-sectional diameter of the single fiber is stretched to 35um; the tension of the bundle during the washing process is 3.5 cN / dtex; 3.0 times stretching is performed during the hot water stretching process; a tension of 2.0 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 22um; saturated water vapor is used for 4 times stretching during the steam stretching process; a tension of 1.0 cN / dtex is applied to stretch the cross-sectional diameter of the single fiber to 10um; a tension of 1.0 cN / dtex is applied during the pre-oxidation process until the density is 1.36g / cm3; sizing: before sizing, the filaments are first sorted, and the fibers are evenly arranged on the rollers. Each group of rollers includes 5 roller rollers, and the tension between the rollers is maintained at 0.2 cN / dtex. After being sorted by 2 groups of roller rollers, a fiber bundle with uniform wire width is formed, and then immersed in the sizing tank for sizing. After sizing, the filaments are dried, and the dried fibers are sorted for the second time.

[0019] The relationship between the application process of carbon fiber and woven fabric in Example 1, Example 2 and Example 3 is shown in Table 1:

Claims

1. A method for preparing carbon fiber suitable for woven fabrics, comprising the following steps: Polymerization: acrylonitrile and comonomer are polymerized in dimethyl sulfoxide solution; De-monomerization and degassing: Under vacuum conditions, the residual acrylonitrile monomer in the polymerization solution is separated from the system to separate the monomer; the mixed gas in the polymerization solution is removed to eliminate bubbles and obtain a stable spinning solution; Coagulation molding: The spinning solution is output through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected. The wet spinning process or dry-wet spinning process is adopted, and the spinning solution enters the coagulation liquid to coagulate and form coagulated filaments. Tension is applied to the coagulated filaments after they leave the coagulation bath and before they enter the water for washing. Washing: Wash the coagulated filaments with water, using a roller beating method, and the direction of the water flow is countercurrent; Hot water drawing: The washed silk is stretched by 1.2 to 4 times the tension in hot water; Oiling and drying and densification: Use modified silicone oil or non-silicone oil to oil the coagulated filaments after washing and drawing, and use hot rollers to dry and densify; Steam drawing: Use saturated steam to apply tension for 1.5 to 6 times drawing; Heat setting: Use saturated steam to heat set the fiber; Raw silk collection: The raw silk is collected by a winding machine to obtain finished raw silk; Pre-oxidation: Apply tension to the raw silk in an environment of 200-300°C for oxidation treatment; Low temperature carbonization: The pre-oxidized wire strips are subjected to low temperature carbonization treatment at 300-800°C; High temperature carbonization: The wire strips after low temperature carbonization are subjected to high temperature carbonization treatment at 1000-1600°C; Surface treatment: Apply a constant current to the high-temperature carbonized wire in an electrolytic solution for surface treatment, and then wash it with water; Sizing: Before sizing, the silk strips are first arranged to evenly arrange the fibers on the rollers. Each group of rollers includes ≥5 rollers. After being arranged by more than 2 groups of rollers, a fiber bundle with uniform wire width is formed, and then immersed in the sizing tank for sizing. After sizing, the silk strips are dried, and the dried fibers are arranged for the second time; 15. Carbon fiber winding: Use a winding machine to collect the carbon fiber to obtain finished carbon fiber; In the polymerization step, the comonomer may be one or more of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

2. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the coagulation molding step, the tension, i.e., the bath tension, is in the range of 0.5-1.0 cN / dtex, and the cross-sectional diameter of the monofilament is stretched to 30-40 um.

3. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the water washing step, the water temperature of the water washing is controlled at 30-70°C, and the tension range of the tow during the water washing process is 1.0-3.5 cN / dtex.

4. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the hot water drawing step, the applied tension is 1.0-2.0 cN / dtex, and the cross-sectional diameter of the monofilament is drawn to 19-26 um.

5. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the oiling and drying and densification steps, the drying and densification temperature is 100-190°C.

6. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the steam drawing step, the applied tension is 0.5-1.0 cN / dtex, and the cross-sectional diameter of the monofilament is drawn to 9-12 um.

7. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the pre-oxidation step, the applied tension is 0.5-1.0 cN / dtex and the density is 1.35-1.40 g / cm 3 .

8. The method for preparing carbon fiber suitable for woven fabrics according to claim 1, characterized in that In the sizing step, the tension between the rollers is less than 0.5 cN / dtex.

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