Sizing agent for carbon fiber, carbon fiber and preparation method of sizing agent

Abstract

The invention provides a sizing agent for carbon fibers, the carbon fibers and a preparation method of the carbon fibers, and belongs to the technical field of carbon fiber manufacturing. The sizing agent for the carbon fibers comprises the following components in parts by mass: 100 parts of bisphenol A type epoxy resin, 10-30 parts of glycidyl ester type epoxy resin, 0.5-2 parts of a lubricant, 20-50 parts of a surfactant and 10-20 parts of an organic solvent, and the sizing agent can improve the ductility of the corresponding carbon fibers and reduce the broken filament amount of the carbon fibers.

Description

Technical Field

[0001] The present application relates to the technical field of carbon fiber manufacturing, and in particular to a sizing agent for carbon fiber, carbon fiber and a preparation method thereof. Background Art

[0002] Carbon fiber has the advantages of light weight, high strength, high rigidity, corrosion resistance and high temperature resistance, and is widely used in aerospace, automobile manufacturing, sports equipment, and construction materials. Carbon fiber prepreg generally refers to a composite material that is processed by high pressure and high temperature technology by compounding matrix resin with carbon fiber, and then successively through coating, hot pressing, cooling, laminating, and winding steps, and is generally composed of materials such as carbon fiber, matrix resin, and release paper. Among them, the ductility and fuzzing amount of carbon fiber will directly affect the surface flatness and cloth appearance quality of carbon fiber prepreg, and the sizing technology can play the role of clustering and shaping, friction protection, and interface performance transmission of carbon fiber, which is one of the important factors affecting the performance of carbon fiber such as ductility and fuzzing. However, the existing sizing agent is unreasonable due to the unreasonable formulation design, resulting in poor performance such as ductility and fuzzing of carbon fiber, which in turn causes the quality of carbon fiber reinforced composite materials to be affected (for example, there are poor quality problems such as zebra crossings, flash seams, and flash points in composite materials). Summary of the invention

[0003] The purpose of the present application is to provide a sizing agent for carbon fiber, carbon fiber and a preparation method thereof, wherein the sizing agent can improve the ductility of the corresponding carbon fiber and reduce the amount of fuzz thereof.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a sizing agent for carbon fiber, which includes, by weight, 100 parts of bisphenol A epoxy resin, 10 to 30 parts of glycidyl ester epoxy resin, 0.5 to 2 parts of lubricant, 20 to 50 parts of surfactant and 10 to 20 parts of organic solvent.

[0006] In the above technical solution, the sizing agent is composed of several specific functional components and the amount of each component is limited. Specifically, the sizing agent contains a specific amount of glycidyl ester epoxy resin, which can improve the ductility of the corresponding carbon fiber and reduce the amount of fuzz; at the same time, a specific amount of lubricant is added to the sizing agent, which can work together with the glycidyl ester epoxy resin to more effectively reduce the amount of fuzz of the corresponding carbon fiber; in addition, the sizing agent of this specific formula has the advantage of a higher interface bonding strength between the carbon fiber and the matrix resin after sizing.

[0007] In some optional embodiments, the glycidyl ester type epoxy resin includes at least one of a diglycidyl phthalate type epoxy resin, a diglycidyl terephthalate type epoxy resin, and a diglycidyl isophthalate type epoxy resin.

[0008] In the above technical solution, a specific type of glycidyl ester epoxy resin is used, which can better adapt to the other components in the sizing agent, thereby being more helpful in improving the ductility of the corresponding carbon fiber and reducing the amount of fuzz.

[0009] In some optional embodiments, the bisphenol A type epoxy resin includes at least one of epoxy resin E55, epoxy resin E51, epoxy resin E44 and epoxy resin E42.

[0010] In the above technical solution, there are many applicable types of bisphenol A epoxy resin, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solution provided in the embodiment of the present application.

[0011] In some optional embodiments, the lubricant includes at least one of stearamide, butyl stearate, and triacetin.

[0012] In the above technical solution, a specific type of lubricant is used, which can be better adapted to the glycidyl ester epoxy resin, thereby being more helpful in reducing the amount of carbon fiber fuzz.

[0013] In some optional embodiments, the organic solvent includes at least one of n-butanol, 1,4-butanediol, ethylene glycol monobutyl ether, and propylene glycol methyl ether.

[0014] In the above technical solution, a specific type of organic solvent is used to enable the remaining functional components to exist stably in the sizing agent, which helps to improve the overall stability of the sizing agent.

[0015] In some optional embodiments, the surfactant includes at least one of fatty alcohol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, polyethylene glycol fatty acid ester, polyethylene glycol and polyoxyethylene sorbitan fatty acid ester.

[0016] In the above technical solution, there are many applicable types of surfactants, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solution provided in the embodiment of the present application.

[0017] In a second aspect, an embodiment of the present application provides a carbon fiber, including a carbon fiber substrate and a coating located on the surface of the carbon fiber substrate, wherein the coating is obtained by coating with a sizing agent as provided in the embodiment of the first aspect and then drying.

[0018] In the above technical solution, the coating on the surface of the carbon fiber is obtained by drying the sizing agent provided in the first aspect embodiment, and with the help of a reasonable formula design of the sizing agent, the carbon fiber has the advantages of excellent ductility and less fuzz.

[0019] In some optional embodiments, in the carbon fibers, the mass of the coating layer accounts for 1 to 1.4% of the mass of the carbon fibers.

[0020] In the above technical solution, the mass of the coating in the carbon fiber is limited to a specific range, which helps to reduce the amount of fuzz in the corresponding carbon fiber while taking into account appropriate stiffness.

[0021] In a third aspect, an embodiment of the present application provides a method for preparing carbon fiber as provided in the embodiment of the second aspect, comprising the following steps: diluting the sizing agent and applying it to the surface of the carbon fiber substrate, and then sequentially subjecting the substrate to a pre-drying treatment and a drying treatment to obtain the carbon fiber.

[0022] In some optional embodiments, in the pre-drying step, the treatment temperature of the drying roller is 120-150°C, and the treatment time is 10-30s; and / or, in the drying step, the treatment temperature of the heating box is 180-240°C, and the treatment time is 30-60s.

[0023] In the above technical solution, the treatment temperature and duration in the pre-drying and drying steps are limited to specific ranges, which helps to reduce the amount of fuzz on the surface of the carbon fiber while taking into account appropriate stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A process flow chart of a method for preparing carbon fiber provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0027] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three situations of “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0028] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0029] The sizing agent for carbon fiber, carbon fiber and preparation method thereof according to the embodiments of the present application are described in detail below.

[0030] In a first aspect, an embodiment of the present application provides a sizing agent for carbon fiber, which includes, by weight, 100 parts of bisphenol A epoxy resin, 10 to 30 parts of glycidyl ester epoxy resin, 0.5 to 2 parts of lubricant, 20 to 50 parts of surfactant and 10 to 20 parts of organic solvent.

[0031] In the present application, the sizing agent is composed of several specific functional components and the dosage of each component is limited. Specifically, the sizing agent contains a specific amount of glycidyl ester epoxy resin, which can improve the ductility of the corresponding carbon fiber and reduce the amount of fuzz; at the same time, a specific amount of lubricant is added to the sizing agent, which can work together with the glycidyl ester epoxy resin to more effectively reduce the amount of fuzz of the corresponding carbon fiber; in addition, the sizing agent of the specific formula has the advantage of a higher interface bonding strength between the carbon fiber and the matrix resin after sizing.

[0032] It is understandable that sizing agents are usually emulsions, so there is water in the sizing agents. The specific amount of water is not limited and can be adjusted according to actual needs.

[0033] In order to better understand the sizing agent formula provided in the examples of the present application, the dosage effects of some functional components are specifically described here.

[0034] Specifically, the glycidyl ester epoxy resin is controlled at 10 to 30 parts because if the amount of glycidyl ester epoxy resin is too low, the effect of the sizing agent in improving the ductility of the carbon fiber and reducing the amount of fuzz will be relatively limited; if the amount of glycidyl ester epoxy resin is too high, the bundling of the sizing agent will be reduced, thereby reducing the effect of reducing the amount of fuzz, and at the same time, it will also lead to a decrease in the interface bonding strength between the carbon fiber and the matrix resin.

[0035] Specifically, the lubricant is controlled at 0.5 to 2 parts because if the amount of lubricant is too low, the effect of the sizing agent in reducing the amount of carbon fiber fuzz will be relatively limited; if the amount of lubricant is too high, the bonding between the carbon fiber and the matrix resin will be reduced, thereby reducing the interface bonding strength between the carbon fiber and the matrix resin.

[0036] Specifically, the surfactant is controlled at 20 to 50 parts because if the amount of surfactant is too low, the emulsion stability will be poor; if the amount of surfactant is too high, the bonding between the carbon fiber and the matrix resin will be reduced, thereby reducing the interface bonding strength between the carbon fiber and the matrix resin.

[0037] As an example, the glycidyl ester type epoxy resin includes at least one of diglycidyl phthalate type epoxy resin, diglycidyl terephthalate type epoxy resin, and diglycidyl isophthalate type epoxy resin.

[0038] In this embodiment, a specific type of glycidyl ester epoxy resin is used, which can better adapt to the other components in the sizing agent, thereby being more helpful in improving the ductility of the corresponding carbon fiber and reducing the amount of fuzz.

[0039] In other possible implementations, other common types of glycidyl ester epoxy resins in the art may also be used.

[0040] It should be noted that the type of bisphenol A epoxy resin is not limited and can be selected according to the conventional method in the art.

[0041] As an example, the bisphenol A type epoxy resin includes at least one of epoxy resin E55, epoxy resin E51, epoxy resin E44, and epoxy resin E42.

[0042] In this embodiment, there are many applicable types of bisphenol A epoxy resins, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of the present application.

[0043] As an example, the lubricant includes at least one of stearamide, butyl stearate, and triacetylhydroxystearate.

[0044] In this embodiment, a specific type of lubricant is used, which can be better adapted to the glycidyl ester epoxy resin, thereby being more helpful in reducing the amount of carbon fiber fuzz.

[0045] In other possible implementations, other common types of lubricants in the art may also be used.

[0046] It should be noted that the type of organic solvent is not limited and can be selected according to routine practices in the art.

[0047] As an example, the organic solvent includes at least one of n-butanol, 1,4-butanediol, ethylene glycol monobutyl ether, and propylene glycol methyl ether.

[0048] In this embodiment, a specific type of organic solvent is used to enable the remaining functional components to exist stably in the sizing agent, which helps to improve the overall stability of the sizing agent.

[0049] It should be noted that the type of surfactant is not limited and can be selected according to routine practices in the art.

[0050] As an example, the surfactant includes at least one of fatty alcohol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, polyethylene glycol fatty acid ester, polyethylene glycol and polyoxyethylene sorbitan fatty acid ester.

[0051] In this embodiment, there are many applicable types of surfactants, which can provide more feasible implementation plans, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of the present application.

[0052] It should be noted that the components in the sizing agent that are not particularly described or limited can be arranged according to conventional selection in the art. For example, some auxiliary components can be added to the sizing agent according to actual needs.

[0053] It should be noted that the preparation method of the sizing agent can be carried out according to the conventional preparation process of the emulsion in the art.

[0054] As an example, the preparation method of the sizing agent includes the following steps: mixing bisphenol A type epoxy resin, glycidyl ester type epoxy resin, lubricant, surfactant and organic solvent according to mass parts, and then adding water to the mixed solution for phase inversion emulsification to obtain a sizing agent emulsion.

[0055] In a second aspect, an embodiment of the present application provides a carbon fiber, including a carbon fiber substrate and a coating located on the surface of the carbon fiber substrate, wherein the coating is obtained by coating with a sizing agent as provided in the embodiment of the first aspect and then drying.

[0056] In the present application, the coating on the surface of the carbon fiber is obtained by drying the sizing agent provided in the first aspect embodiment, and with the help of a reasonable formula design of the sizing agent, the carbon fiber has the advantages of excellent ductility and less fuzz.

[0057] As an example, in the carbon fiber, the mass of the coating accounts for 1-1.4% of the mass of the carbon fiber, such as but not limited to any point value of 1%, 1.1%, 1.2%, 1.3% and 1.4% or a range value between any two of them.

[0058] In this embodiment, limiting the mass of the coating in the carbon fiber to a specific range helps to reduce the amount of fuzz in the corresponding carbon fiber while maintaining appropriate stiffness.

[0059] In a third aspect, an embodiment of the present application provides a method for preparing carbon fiber as provided in the embodiment of the second aspect, comprising the following steps: diluting the sizing agent and applying it to the surface of the carbon fiber substrate, and then sequentially subjecting the substrate to a pre-drying treatment and a drying treatment to obtain the carbon fiber.

[0060] It should be noted that, in the pre-drying step, a drying roller is usually used as the pre-drying equipment, so that the pre-drying is achieved by direct contact between the carbon fiber surface and the roller surface; in the drying step, a heating furnace or a heating box is usually used as the drying equipment, so that the carbon fiber is indirectly dried by heating the air.

[0061] As an example, in the pre-drying treatment step, the treatment temperature of the drying roller is 120-150°C, for example but not limited to the treatment temperature being any point value among 120°C, 130°C, 140°C and 150°C or a range value between any two of them; the treatment time is 10-30s, for example but not limited to the treatment time being any point value among 10s, 15s, 20s, 25s and 30s or a range value between any two of them; and / or, in the drying treatment step, the treatment temperature of the heating box is 180-240°C, for example but not limited to the treatment temperature being any point value among 180°C, 190°C, 200°C, 210°C, 220°C, 230°C and 240°C or a range value between any two of them; the treatment time is 30-60s, for example but not limited to the treatment time being any point value among 30s, 40s, 50s and 60s or a range value between any two of them.

[0062] In this embodiment, the treatment temperature and duration in the pre-drying and drying steps are limited to specific ranges, which helps to reduce the amount of fuzz on the surface of the carbon fiber while taking into account appropriate stiffness.

[0063] It should be noted that, in the process of preparing carbon fiber, any process or step not specifically described or limited can be arranged according to conventional selection in the art.

[0064] As an example, the process flow chart of preparing carbon fiber using the sizing agent provided in the embodiment of the present application is shown as follows: Figure 1 shown.

[0065] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0066] Example 1

[0067] The present invention provides a method for preparing carbon fiber, comprising the following steps:

[0068] 100 parts of bisphenol A epoxy resin E55, 20 parts of diglycidyl phthalate, 1 part of stearamide (lubricant), 35 parts of fatty alcohol polyoxyethylene ether (surfactant) and 15 parts of n-butanol (organic solvent) were mixed, and then water was added to the mixed system for reverse emulsification to obtain a sizing agent.

[0069] The diluted sizing agent is applied to the surface of the carbon fiber substrate, and then pre-dried and dried in sequence to obtain carbon fiber. The pre-drying process is carried out using a drying roller, the treatment temperature is 135°C, and the treatment time is 15s; the drying process is carried out using a drying oven, the treatment temperature is 220°C, and the treatment time is 45s. In the carbon fiber, the mass of the coating accounts for 1.2% of the mass of the carbon fiber.

[0070] Example 2

[0071] The present embodiment provides a method for preparing carbon fiber, which differs from the embodiment 1 only in that:

[0072] 100 parts of bisphenol A epoxy resin E55, 10 parts of diglycidyl phthalate, 0.5 parts of stearamide (lubricant), 20 parts of fatty alcohol polyoxyethylene ether (surfactant) and 10 parts of n-butanol (organic solvent) were mixed, and then water was added to the mixed system for reverse emulsification to obtain a sizing agent.

[0073] Example 3

[0074] The present embodiment provides a method for preparing carbon fiber, which differs from the embodiment 1 only in that:

[0075] 100 parts of bisphenol A epoxy resin E55, 30 parts of diglycidyl phthalate, 2 parts of stearamide (lubricant), 50 parts of fatty alcohol polyoxyethylene ether (surfactant) and 20 parts of n-butanol (organic solvent) were mixed, and then water was added to the mixed system for reverse emulsification to obtain a sizing agent.

[0076] Example 4

[0077] The embodiment of the present application provides a method for preparing carbon fiber, which is different from Embodiment 1 only in that all diglycidyl phthalate is replaced by diglycidyl adipate.

[0078] Example 5

[0079] The embodiment of the present application provides a method for preparing carbon fiber, which differs from Embodiment 1 only in that all stearamide is replaced by oleamide.

[0080] Example 6

[0081] The embodiment of the present application provides a method for preparing carbon fiber, which differs from Embodiment 1 only in that: in the carbon fiber, the mass of the coating accounts for 1.0% of the mass of the carbon fiber.

[0082] Example 7

[0083] The embodiment of the present application provides a method for preparing carbon fiber, which differs from Embodiment 1 only in that, in the carbon fiber, the mass of the coating accounts for 1.4% of the mass of the carbon fiber.

[0084] Example 8

[0085] The embodiment of the present application provides a method for preparing carbon fiber, which is different from Embodiment 1 only in that: in the carbon fiber, the mass of the coating accounts for 0.8% of the mass of the carbon fiber.

[0086] Example 9

[0087] The embodiment of the present application provides a method for preparing carbon fiber, which differs from Embodiment 1 only in that, in the carbon fiber, the mass of the coating accounts for 1.6% of the mass of the carbon fiber.

[0088] Comparative Example 1

[0089] The comparative example of the present application provides a method for preparing carbon fiber, which is different from Example 1 only in that diglycidyl phthalate is not added.

[0090] Comparative Example 2

[0091] The comparative example of the present application provides a method for preparing carbon fiber, which is different from Example 1 only in that stearamide (lubricant) is not added.

[0092] Comparative Example 3

[0093] The comparative example of the present application provides a method for preparing carbon fiber, which is different from Example 1 only in that: 40 parts of diglycidyl phthalate.

[0094] Comparative Example 4

[0095] The comparative example of the present application provides a method for preparing carbon fiber, which differs from Example 1 only in that: 3 parts of stearamide (lubricant).

[0096] Comparative Example 5

[0097] The comparative example of the present application provides a method for preparing carbon fiber, which differs from Example 1 only in that: 60 parts of fatty alcohol polyoxyethylene ether (surfactant).

[0098] In order to better understand the technical solution, the parameters of various embodiments and comparative examples are summarized and explained in a table.

[0099] Table 1 Summary of relevant parameters of various embodiments and comparative examples

[0100]

[0101]

[0102] Test example

[0103] Carbon fiber performance test

[0104] Test method:

[0105] The carbon fibers prepared in Examples 1 to 9 and Comparative Examples 1 to 5 were numbered, and the ductility and surface fuzziness of each sample were tested. Each sample was then composited with an epoxy resin matrix and the interlaminar shear strength of the composite material was tested. Specifically, the interlaminar shear strength was determined according to JC / T773-2010 and GB / T 30969.

[0106] Table 2 Performance statistics of each sample

[0107]

[0108]

[0109] Referring to Table 2, it can be seen from the test results of Examples 1 to 9 and Comparative Example 1 that, compared with not adding glycidyl ester epoxy resin to the sizing agent, the former corresponds to carbon fiber with better ductility and less hair on the surface of the carbon fiber.

[0110] From the test results of Examples 1 to 9 and Comparative Example 2, it can be seen that when a lubricant is added to the sizing agent, the amount of fuzz on the surface of the corresponding carbon fiber is less than when no lubricant is added to the sizing agent.

[0111] It can be seen from the test results of Examples 1 to 3 and Comparative Examples 3 to 5 that the amount of glycidyl ester epoxy resin, lubricant and surfactant is limited to a specific range, respectively. Compared with not being within the specific range, the carbon fiber corresponding to the former can simultaneously take into account better ductility, less fuzz and higher interface bonding strength.

[0112] From the test results of Examples 1 to 3 and Examples 4 to 5, it can be seen that the carbon fibers corresponding to specific types of glycidyl ester epoxy resins and lubricants can simultaneously have better ductility, less fuzz and higher interface bonding strength than other conventional types.

[0113] It can be seen from the test results of Examples 1 to 3 and Examples 6 to 9 that limiting the coating quality in the carbon fiber to a specific range, compared to not limiting the coating quality in the carbon fiber to a specific range, the carbon fiber corresponding to the former can simultaneously take into account better ductility, less fuzz and higher interface bonding strength.

[0114] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A sizing agent for carbon fiber, It is characterized in that According to the mass percentage, it includes: 100 parts of bisphenol A type epoxy resin, 10-30 parts of glycidyl ester type epoxy resin, 0.5-2 parts of lubricant, 20-50 parts of surfactant and 10-20 parts of organic solvent.

2. The sizing agent for carbon fiber according to claim 1, It is characterized in that The glycidyl ester epoxy resin includes at least one of diglycidyl phthalate epoxy resin, diglycidyl terephthalate epoxy resin and diglycidyl isophthalate epoxy resin.

3. The sizing agent for carbon fiber according to claim 1, It is characterized in that The bisphenol A type epoxy resin includes at least one of epoxy resin E55, epoxy resin E51, epoxy resin E44 and epoxy resin E42.

4. The sizing agent for carbon fiber according to claim 1, It is characterized in that The lubricant includes at least one of stearamide, butyl stearate and triacetylhydroxystearate.

5. The sizing agent for carbon fiber according to claim 1, It is characterized in that The organic solvent includes at least one of n-butanol, 1,4-butanediol, ethylene glycol monobutyl ether and propylene glycol methyl ether.

6. The sizing agent for carbon fiber according to claim 1, It is characterized in that The surfactant includes at least one of fatty alcohol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, polyethylene glycol fatty acid ester, polyethylene glycol and polyoxyethylene sorbitan fatty acid ester.

7. A carbon fiber, It is characterized in that The invention comprises a carbon fiber substrate and a coating on the surface of the carbon fiber substrate, wherein the coating is obtained by coating with the sizing agent according to any one of claims 1 to 6 and then drying.

8. The carbon fiber according to claim 7, It is characterized in that In the carbon fiber, the mass of the coating accounts for 1 to 1.4% of the mass of the carbon fiber.

9. A method for preparing carbon fiber according to claim 7 or 8, It is characterized in that The following steps are involved: The sizing agent is diluted and coated on the surface of the carbon fiber substrate, and then subjected to a pre-drying treatment and a drying treatment in sequence to obtain the carbon fiber.

10. The preparation method according to claim 9, It is characterized in that In the step of pre-drying, the treatment temperature of the drying roller is 120-150°C, and the treatment time is 10-30s; and / or, In the drying step, the treatment temperature of the heating box is 180-240° C., and the treatment time is 30-60 seconds.

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