Polymerization method for preparing high-strength and high-model carbon fibers

Abstract

The invention discloses a polymerization method for preparing high-strength and high-model carbon fibers, which mainly comprises the following steps of: polymerizing, solidifying and forming, washing with water, drafting with hot water, oiling, drying and densifying, drafting with steam, heat-setting and collecting the protofilaments according to the preparation of the protofilaments to obtain the finished protofilaments. The method comprises the following steps: S1, polymerization: polymerizing a reaction solution composed of acrylonitrile, a comonomer and a dimethyl sulfoxide solution in two steps; s2, monomer removal and defoaming: separating residual acrylonitrile monomers in the polymerization liquid from a system under a vacuum condition, removing mixed gas in the polymerization liquid, and eliminating bubbles to obtain a stable spinning solution. Compared with the prior art, the polymerization method for preparing the high-strength and high-model carbon fibers has the advantages that the good spinning solution is formed through polymerization, and the tensile strength and the tensile modulus of the carbon fibers are helped to be improved at the same time in cooperation with precursor production conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of organic polymer materials, and in particular provides a polymerization method for preparing high-strength and high-model carbon fibers through the improvement of the polymerization process. Background Art

[0002] The performance of carbon fiber in the production process, especially the strength, depends on the mechanical properties of the precursor, which in turn depends on the polymerized spinning solution. Therefore, an excellent polymerization process is the basis and an indispensable research topic. Obtaining uniform high molecular weight materials is an ideal result. Chain initiation and chain growth are two reaction processes in the polymerization process. The coordination of the polymerization process and the polymerization flow can obtain an ideal spinning solution. This is also for the smooth coagulation, oiling and drawing of carbon fiber precursors, as well as the matching of carbon fiber pre-oxidation, carbonization and other processes. Therefore, it is necessary to study the effectiveness and controllability of polymerization.

[0003] In view of the above technical problems, it is necessary to provide a polymerization method for preparing high-strength and high-model carbon fibers.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a polymerization method for preparing high-strength and high-model carbon fibers, which can achieve the purpose of improving the tensile strength of the carbon fibers.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0007] A polymerization method for preparing high-strength and high-model carbon fiber comprises the following steps:

[0008] S1, polymerization: polymerizing a reaction solution consisting of acrylonitrile, comonomer and dimethyl sulfoxide solution in two steps;

[0009] S1.1, adding part of the reaction solution into the first reactor for polymerization, and putting the remaining reaction solution into a storage tank for polymerization;

[0010] S1.2, after the reaction of the first reactor is completed, the obtained material and the remaining reaction liquid in the storage tank are simultaneously put into the second reactor, and a static mixer is used to mix them during the input process. After the reaction of the second reactor is completed, a polymer solution is obtained;

[0011] S2, de-monomerization and degassing: under vacuum conditions, the remaining acrylonitrile monomer in the polymerization solution is separated from the system, and the mixed gas in the polymerization solution is removed to eliminate bubbles to obtain a spinning solution;

[0012] S3, coagulation and forming: the spinning solution is outputted through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, adopts the spinning process, enters the coagulation liquid to coagulate and form coagulated filaments, and leaves the bath;

[0013] S4, washing: washing the coagulated filaments with water;

[0014] S5, shaping: the coagulated filaments after water washing are sequentially subjected to hot water drawing, oiling and drying densification, steam drawing and heat shaping to obtain raw silk;

[0015] S6. Raw silk collection: using a winding machine to collect the raw silk to obtain finished raw silk.

[0016] In one or more embodiments of the present invention, in S1, the comonomer may be one or more combinations of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

[0017] In one or more embodiments of the present invention, in S1.1, the feeding amount of the first reactor is 70%-80%, and the reaction temperature is 60-70°C;

[0018] In S1.2, the reaction temperature of the second reactor is 70-80°C.

[0019] In one or more embodiments of the present invention, in S3, the specific steps of separating the bath are:

[0020] The coagulated filaments are subjected to tension after exiting the coagulation liquid and before entering the water for washing, and the tension is the tension after leaving the bath;

[0021] The bath tension range is 0.5-1.0 cN / dtex;

[0022] The ambient temperature of the bath is 20-30° C., and the ambient humidity is not less than 50%.

[0023] In one or more embodiments of the present invention, in S4, the water washing adopts a flower roller beating type water washing, the water flow direction of the water washing is countercurrent, and the number of water washing tanks is 6-11;

[0024] The water temperature of the water washing is 30-70°C, and the tension range of the tow during the water washing process is 1.0-3.5 cN / dtex.

[0025] In one or more embodiments of the present invention, in S5, the specific steps of hot water drawing are:

[0026] The washed coagulated filaments are drawn 1.2-4.0 times in hot water.

[0027] In one or more embodiments of the present invention, in S5, the specific steps of oiling and drying and densification are:

[0028] The coagulated filaments after washing and hot water drawing are oiled with modified silicone oil or non-silicone oil, and dried and densified with hot rollers.

[0029] In one or more embodiments of the present invention, the drying and densification process is divided into two parts, the first drying and densification temperature is 100-140°C, and the second drying and densification temperature is 150-190°C.

[0030] In one or more embodiments of the present invention, in S5, the specific steps of steam drawing are:

[0031] The coagulated filaments after oiling and drying and densification are drawn 1.5-6.0 times using saturated steam to obtain fibers.

[0032] In one or more embodiments of the present invention, in S5, the specific steps of heat setting are:

[0033] The fibers are heat set using saturated steam.

[0034] Compared with the prior art, the polymerization method for preparing high-strength and high-model carbon fiber of the present invention forms a good spinning solution through polymerization, and cooperates with the production conditions of the raw yarn to help improve the tensile strength and tensile modulus of the carbon fiber at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 The present invention is a flowchart of a polymerization method for preparing high-strength and high-model carbon fiber in one embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] like Figure 1 As shown, a polymerization method for preparing high-strength and high-model carbon fiber in one embodiment of the present invention mainly includes the following steps of polymerization, coagulation molding, water washing, hot water drawing, oiling and drying densification, steam drawing, heat setting, and raw silk collection to obtain finished raw silk.

[0039] Embodiment 1

[0040] S1. Polymerization: polymerizing the reaction solution consisting of acrylonitrile, comonomer and dimethyl sulfoxide solution in two steps. Preferably, the comonomer can be one or more combinations of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

[0041] S1.1, put 70% of the reaction liquid into the first reactor for polymerization reaction, the reaction temperature is 65°C, and the remaining 30% of the reaction liquid is put into a storage tank for polymerization;

[0042] S1.2, after the reaction in the first reactor is completed, the obtained material and the remaining 30% of the reaction liquid in the storage tank are put into the second reactor at the same time, the reaction temperature is 75°C, after the reaction in the second reactor is completed, a polymer solution is obtained;

[0043] The first reactor and the second reactor were mixed by a static mixer during the feeding process, with a mixing temperature of 70° C. and a mixing time of 0.5 h.

[0044] S2. De-monomerization and degassing: Under vacuum conditions, the remaining acrylonitrile monomer in the polymerization solution is separated from the system, and the mixed gas in the polymerization solution is removed to eliminate bubbles and obtain a stable spinning solution.

[0045] S3, coagulation and molding: the spinning solution is outputted through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, adopts the wet spinning process or the dry-wet spinning process, enters the coagulation liquid and coagulates into coagulated filaments, and leaves the bath.

[0046] Among them, the specific steps of leaving the bath are:

[0047] Tension is applied to the coagulated filaments after they come out of the coagulation liquid and before they enter the water for washing. The tension is the tension after leaving the bath. The tension ranges from 0.5 to 1.0 cN / dtex. The ambient temperature of the bath is 20 to 30°C and the ambient humidity is not less than 50%.

[0048] S4. Washing: Wash the coagulated filaments with water. The washing adopts the flower roller beating type washing. The washing water flow direction is countercurrent. The number of washing tanks is 6-11. The water temperature of the washing is 30-70°C. The tension range of the filament bundle during the washing process is 1.0-3.5 cN / dtex.

[0049] S5. Setting: The coagulated filaments after water washing are sequentially drawn by hot water, oiled and dried for densification, steam drawn and heat set to obtain raw silk.

[0050] Hot water drawing: The washed coagulated filaments are drawn in hot water at 1.2-4.0 times.

[0051] Oiling and drying densification: Use modified silicone oil or non-silicone oil to oil the coagulated filaments after water washing and hot water drawing, and use hot rollers to dry and densify.

[0052] The drying and densification process is divided into two parts: the first drying and densification temperature is 100-140°C, and the second drying and densification temperature is 150-190°C.

[0053] Steam drawing: Use saturated water vapor to draw the coagulated filaments after oiling and drying to 1.5-6.0 times to obtain fibers.

[0054] Heat setting: Use saturated water vapor to heat set the fibers.

[0055] S6. Raw silk collection: The raw silk is collected by a winding machine to obtain finished raw silk.

[0056] Embodiment 2

[0057] S1. Polymerization: polymerizing the reaction solution consisting of acrylonitrile, comonomer and dimethyl sulfoxide solution in two steps. Preferably, the comonomer can be one or more combinations of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

[0058] S1.1, put 75% of the reaction liquid into the first reactor for polymerization reaction, the reaction temperature is 65°C, and the remaining 25% of the reaction liquid is put into a storage tank for polymerization;

[0059] S1.2, after the reaction in the first reactor is completed, the obtained material and the remaining 25% of the reaction liquid in the storage tank are put into the second reactor at the same time, the reaction temperature is 75°C, and after the reaction in the second reactor is completed, a polymer solution is obtained;

[0060] The first reactor and the second reactor were mixed by a static mixer during the feeding process, with a mixing temperature of 70° C. and a mixing time of 0.5 h.

[0061] S2. De-monomerization and degassing: Under vacuum conditions, the remaining acrylonitrile monomer in the polymerization solution is separated from the system, and the mixed gas in the polymerization solution is removed to eliminate bubbles and obtain a stable spinning solution.

[0062] S3, coagulation and molding: the spinning solution is outputted through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, adopts the wet spinning process or the dry-wet spinning process, enters the coagulation liquid and coagulates into coagulated filaments, and leaves the bath.

[0063] Among them, the specific steps of leaving the bath are:

[0064] Tension is applied to the coagulated filaments after they come out of the coagulation liquid and before they enter the water for washing. The tension is the tension after leaving the bath. The tension ranges from 0.5 to 1.0 cN / dtex. The ambient temperature of the bath is 20 to 30°C and the ambient humidity is not less than 50%.

[0065] S4. Washing: Wash the coagulated filaments with water. The washing adopts the flower roller beating type washing. The washing water flow direction is countercurrent. The number of washing tanks is 6-11. The water temperature of the washing is 30-70°C. The tension range of the filament bundle during the washing process is 1.0-3.5 cN / dtex.

[0066] S5. Setting: The coagulated filaments after water washing are sequentially drawn by hot water, oiled and dried for densification, steam drawn and heat set to obtain raw silk.

[0067] Hot water drawing: The washed coagulated filaments are drawn in hot water at 1.2-4.0 times.

[0068] Oiling and drying densification: Use modified silicone oil or non-silicone oil to oil the coagulated filaments after water washing and hot water drawing, and use hot rollers to dry and densify.

[0069] The drying and densification process is divided into two parts: the first drying and densification temperature is 100-140°C, and the second drying and densification temperature is 150-190°C.

[0070] Steam drawing: Use saturated water vapor to draw the coagulated filaments after oiling and drying to 1.5-6.0 times to obtain fibers.

[0071] Heat setting: Use saturated water vapor to heat set the fibers.

[0072] S6. Raw silk collection: The raw silk is collected by a winding machine to obtain finished raw silk.

[0073] Embodiment 3

[0074] S1. Polymerization: polymerizing the reaction solution consisting of acrylonitrile, comonomer and dimethyl sulfoxide solution in two steps. Preferably, the comonomer can be one or more combinations of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

[0075] S1.1, put 70% of the reaction liquid into the first reactor for polymerization reaction, the reaction temperature is 65°C, and the remaining 30% of the reaction liquid is put into a storage tank for polymerization;

[0076] S1.2, after the reaction in the first reactor is completed, the obtained material and the remaining 30% of the reaction liquid in the storage tank are put into the second reactor at the same time, the reaction temperature is 75°C, after the reaction in the second reactor is completed, a polymer solution is obtained;

[0077] The first reactor and the second reactor were mixed by a static mixer during the feeding process, with a mixing temperature of 70° C. and a mixing time of 0.5 h.

[0078] S2. De-monomerization and degassing: Under vacuum conditions, the remaining acrylonitrile monomer in the polymerization solution is separated from the system, and the mixed gas in the polymerization solution is removed to eliminate bubbles and obtain a stable spinning solution.

[0079] S3, coagulation and molding: the spinning solution is outputted through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, adopts the wet spinning process or the dry-wet spinning process, enters the coagulation liquid and coagulates into coagulated filaments, and leaves the bath.

[0080] Among them, the specific steps of leaving the bath are:

[0081] Tension is applied to the coagulated filaments after they come out of the coagulation liquid and before they enter the water for washing. The tension is the tension after leaving the bath. The tension ranges from 0.5 to 1.0 cN / dtex. The ambient temperature of the bath is 20 to 30°C and the ambient humidity is not less than 50%.

[0082] S4. Washing: Wash the coagulated filaments with water. The washing adopts the flower roller beating type washing. The washing water flow direction is countercurrent. The number of washing tanks is 6-11. The water temperature of the washing is 30-70°C. The tension range of the filament bundle during the washing process is 1.0-3.5 cN / dtex.

[0083] S5. Setting: The coagulated filaments after water washing are sequentially drawn by hot water, oiled and dried for densification, steam drawn and heat set to obtain raw silk.

[0084] Hot water drawing: The washed coagulated filaments are drawn in hot water at 1.2-4.0 times.

[0085] Oiling and drying densification: Use modified silicone oil or non-silicone oil to oil the coagulated filaments after water washing and hot water drawing, and use hot rollers to dry and densify.

[0086] The drying and densification process is divided into two parts: the first drying and densification temperature is 100-140°C, and the second drying and densification temperature is 150-190°C.

[0087] Steam drawing: Use saturated water vapor to draw the coagulated filaments after oiling and drying to 1.5-6.0 times to obtain fibers.

[0088] Heat setting: Use saturated water vapor to heat set the fibers.

[0089] S6. Raw silk collection: The raw silk is collected by a winding machine to obtain finished raw silk.

[0090] The relationship between the precursor production process and the tensile strength and modulus of carbon fiber in Example 1, Example 2 and Example 3 is shown in the following table:

[0091]

[0092] The polymerization method for preparing high-strength and high-model carbon fiber of the present invention forms a good spinning solution through polymerization, and cooperates with the production conditions of the raw yarn to help improve the tensile strength and tensile modulus of the carbon fiber at the same time.

[0093] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0094] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A polymerization method for preparing high-strength and high-model carbon fiber, It is characterized in that The following steps are involved: S1, polymerization: polymerizing a reaction solution consisting of acrylonitrile, comonomer and dimethyl sulfoxide solution in two steps; S1.1, adding part of the reaction solution into the first reactor for polymerization, and putting the remaining reaction solution into a storage tank for polymerization; S1.2, after the reaction of the first reactor is completed, the obtained material and the remaining reaction liquid in the storage tank are simultaneously put into the second reactor, and a static mixer is used to mix them during the input process. After the reaction of the second reactor is completed, a polymer solution is obtained; S2, de-monomerization and degassing: under vacuum conditions, the remaining acrylonitrile monomer in the polymerization solution is separated from the system, and the mixed gas in the polymerization solution is removed to eliminate bubbles to obtain a spinning solution; S3, coagulation and forming: the spinning solution is outputted through the spinning metering pump, flows through the buffer, enters the spinneret assembly and is ejected, adopts the spinning process, enters the coagulation liquid and is coagulated into coagulated filaments, and leaves the bath; S4, washing: washing the coagulated filaments with water; S5, shaping: the coagulated filaments after water washing are sequentially subjected to hot water drawing, oiling and drying densification, steam drawing and heat shaping to obtain raw silk; S6. Raw silk collection: using a winding machine to collect the raw silk to obtain finished raw silk.

2. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S1, the comonomer may be one or more combinations of methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, acrylamide, itaconic acid, ammonium itaconate, and isobutyl methacrylate.

3. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S1.1, the feeding amount of the first reactor is 70%-80%, and the reaction temperature is 60-70°C; In S1.2, the reaction temperature of the second reactor is 70-80°C.

4. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S3, the specific steps of the bath separation are: The coagulated filaments are subjected to tension after exiting the coagulation liquid and before entering the water for washing, and the tension is the tension after leaving the bath; The bath tension range is 0.5-1.0 cN / dtex; The ambient temperature of the bath is 20-30° C., and the ambient humidity is not less than 50%.

5. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S4, the washing is performed by a roller beating type washing, the washing water flow direction is countercurrent, and the number of washing tanks is 6-11; The water temperature of the washing is 30-70°C, and the tension range of the tow during the washing process is 1.0-3.5 cN / dtex.

6. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S5, the specific steps of hot water drawing are: The washed coagulated filaments are drawn 1.2-4.0 times in hot water.

7. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S5, the specific steps of oiling and drying and densification are: The coagulated filaments after washing and hot water drawing are oiled with modified silicone oil or non-silicone oil, and dried and densified with hot rollers.

8. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 7, It is characterized in that The drying and densification process is divided into two parts, the first drying and densification temperature is 100-140°C, and the second drying and densification temperature is 150-190°C.

9. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 1, It is characterized in that In S5, the specific steps of steam drawing are: The coagulated filaments after oiling and drying and densification are drawn 1.5-6.0 times using saturated steam to obtain fibers.

10. A polymerization method for preparing high-strength and high-model carbon fiber according to claim 9, It is characterized in that In S5, the specific steps of heat setting are: The fibers are heat set using saturated steam.

Images