Oil agent for carbon fibers as well as preparation method and application of oil agent

Abstract

The invention provides an oiling agent for carbon fibers as well as a preparation method and application thereof, the oiling agent comprises an amino modified silicone oil emulsion and an epoxy modified silicone oil emulsion, and the mass ratio of the amino modified silicone oil emulsion to the epoxy modified silicone oil emulsion is 1: (0.5-1.5); the amino modified silicone oil and the epoxy group-containing modified silicone oil are comb-shaped in structure, main chains of the amino modified silicone oil and the epoxy group-containing modified silicone oil are acrylate polymers, and branch chains of the amino modified silicone oil and the epoxy group-containing modified silicone oil are amino short silane chains or epoxy group-containing short silane chains; the preparation method of the oiling agent comprises the following steps: firstly, preparing an acrylate prepolymer by a solvent polymerization method, then respectively preparing amino modified silicone oil and epoxy group-containing modified silicone oil, and finally respectively carrying out water emulsification. The acrylate polymer is introduced into the oiling agent provided by the invention, so that the silicon content is reduced, the viscosity of the oiling agent is reduced, carbon fibers are conveniently oiled, a protective film is formed on the fibers, friction and abrasion between the fibers are prevented, and the surface defects of the carbon fibers are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of spinning oils, and in particular relates to an oil for carbon fiber and a preparation method and application thereof. Background Art

[0002] Polyacrylonitrile-based carbon fiber is a new material that has developed rapidly in the 1960s. It is widely used in high-end fields such as military industry and aerospace because of its light weight, high specific strength, high specific modulus, high temperature resistance, corrosion resistance, wear resistance, fatigue resistance, electrical conductivity, thermal conductivity, etc. However, carbon fiber is a brittle material, and its own defects are the main factor restricting its tensile strength. Good quality oil and reasonable processing technology are effective means to prevent surface defects.

[0003] In the preparation process of polyacrylonitrile-based carbon fiber, oil agent plays an extremely important role in polyacrylonitrile-based carbon fiber. Its main function is to form a thin film of uniform thickness on the fiber surface, which can effectively prevent or eliminate static electricity generated by friction and reduce the friction coefficient; and give the fiber smoothness, softness and other characteristics, so that the fiber has appropriate bundling, drawing, fiber separation, spinnability, oxidation resistance and heat resistance, and can smoothly pass the pre-oxidation and low-temperature carbonization processes to protect the fiber surface from thermal adhesion or thermal melting.

[0004] Although a large number of developments related to carbon fiber oils have begun to appear in China since 2000, there is still a certain gap between the oil systems that can be applied in batches in China and those abroad, and the main oils on the market are silicone oils. The production of polyacrylonitrile-based carbon fibers generally involves two steps: the production of precursors and the pre-oxidation and carbonization of the precursors. The precursors need to be oiled during production. When oiling, it is necessary to form a uniform film of a certain thickness on the surface and to minimize the penetration of the oil into the fiber. The quality of the oil and the oiling process directly affect the quality of the precursor and carbon fiber. During the high-temperature carbonization process of silicone oils, the residual oil may be converted into hard and brittle silicon-based ceramics such as silicon oxide, which affects the mechanical properties of polyacrylonitrile-based carbon fibers; in addition, the viscosity of silicone oils is often too high to quickly coat the polyacrylonitrile-based carbon fiber precursors. Summary of the invention

[0005] In view of this, the present invention provides an oil agent for carbon fiber and a preparation method and application thereof. The structure of the oil agent provided by the present invention is comb-shaped, the main chain is an acrylate structure chain, and the side chain is a short silane chain containing an epoxy group or an amino group, which reduces the silicone content and makes the oil agent have a lower viscosity, making it convenient to oil the carbon fiber, forming a protective film on the fiber filaments, preventing friction and wear between the filaments, thereby reducing surface defects of the carbon fiber.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] An oil agent for carbon fiber, comprising amino-modified silicone oil emulsion and epoxy-modified silicone oil emulsion, wherein the mass ratio of the amino-modified silicone oil emulsion to the epoxy-modified silicone oil emulsion is 1:0.5-1.5;

[0008] The structures of amino-modified silicone oil and epoxy-modified silicone oil are both comb-shaped, wherein the main chain of the amino-modified silicone oil is an acrylate polymer, and the side chains are short amino silane chains; the main chain of the epoxy-modified silicone oil is an acrylate polymer, and the side chains are short epoxy silane chains;

[0009] The preparation method of the oil agent is as follows: firstly, an acrylate prepolymer is prepared by a solvent polymerization method, then an amino-modified silicone oil and an epoxy-containing modified silicone oil are prepared respectively, and finally they are emulsified in water respectively.

[0010] Based on the same inventive concept, the present invention provides a method for preparing the above-mentioned oil agent for carbon fiber, comprising the following steps:

[0011] S1: preparing acrylate prepolymer;

[0012] S2: preparing amino-modified silicone oil and epoxy-modified silicone oil;

[0013] S3: Amino-modified silicone oil and epoxy-modified silicone oil are emulsified and compounded according to the ratio.

[0014] Preferably, the preparation method of the acrylate prepolymer in step S1 is specifically as follows:

[0015] S101: adding acrylate monomer, chain transfer agent dodecyl mercaptan, and silane coupling agent with double bonds into toluene and mixing evenly;

[0016] S102: dissolving 0.1-2% of the mass of the acrylic acid monomer in an initiator in toluene to obtain an initiator solution;

[0017] S103: In an inert atmosphere, heat the mixed solution of step S101 to 65-85° C., add 1 / 5 of the initiator solution, react for 0.5-1 hour, then add the remaining initiator solution, continue the reaction for 3-6 hours, and remove the solvent from the obtained product liquid to obtain an acrylate prepolymer.

[0018] The preferred conditions for removing the solvent from the product liquid in step S103 are to perform reduced pressure distillation for 30 to 50 minutes at a pressure of 0.1 to 0.5 MPa and a temperature of 70 to 110° C. to remove the solvent and obtain an acrylate prepolymer.

[0019] Preferably, the mass ratio of the acrylic acid ester monomer, the silane coupling agent with double bonds, the chain transfer agent dodecyl mercaptan and toluene is 100:15-30:0.5-2:300-500.

[0020] Preferably, the silane coupling agent with a double bond includes at least one of methacryloxypropylmethyldimethoxysilane, methacryloxypropylmethyldiethoxysilane, vinylmethyldimethoxysilane or vinylmethyldiethoxysilane;

[0021] The acrylic acid ester monomer includes at least one of butyl acrylate, isooctyl acrylate, butyl methacrylate, methyl methacrylate, isobutyl acrylate, isooctyl methacrylate or ethyl acrylate.

[0022] Preferably, the preparation of the amino-modified silicone oil in step S2 includes: taking the sum of the weight percentages of all raw material components as 100%, the raw materials used and their weight percentages are as follows:

[0023]

[0024] Add the aqueous solution of the strong alkaline catalyst together with 1 / 3 of octamethylcyclotetrasiloxane linear body, acrylate prepolymer and 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser and a thermometer, stir evenly, react at 90-110°C for 2-3 hours, then slowly add the remaining octamethylcyclotetrasiloxane linear body and 1 / 3 of the end-capping agent, continue to react for 3-6 hours, then add the remaining end-capping agent and react for 1-2 hours, and after cooling, obtain a uniform translucent viscous liquid to obtain an amino-modified silicone oil.

[0025] Preferably, the preparation of epoxy-containing modified silicon in step S2 includes: taking the sum of the weight percentages of all raw material components as 100%, the raw materials used and their weight percentages are as follows:

[0026]

[0027] Add the aqueous solution of the strong alkaline catalyst together with 1 / 3 of octamethylcyclotetrasiloxane linear body, acrylate prepolymer and 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser and a thermometer, stir evenly, react at 90-110° C. for 2-3 hours, then slowly add the remaining octamethylcyclotetrasiloxane linear body and 1 / 3 of the end-capping agent, continue to react for 3-6 hours, then add the remaining end-capping agent and react for 1-2 hours, and after cooling, obtain a uniform translucent viscous liquid to obtain epoxy-modified silicone oil.

[0028] Preferably, the end-capping agent is hexamethyldisiloxane or pentamethyldisiloxane; the strong alkaline catalyst is any one of potassium hydroxide, sodium hydroxide or tetramethylammonium hydroxide or a mixed catalyst of any of the above.

[0029] Preferably, step S3 specifically comprises: mixing the emulsifier and the amino-modified silicone oil or the epoxy-modified silicone oil in a weight ratio of (1-5):100 in deionized water, adjusting the pH value to neutral, heating to 60-85° C., stirring for 1 hour, and obtaining an amino-modified silicone oil emulsion or an epoxy-modified silicone oil emulsion.

[0030] Preferably, the emulsifier is a nonionic emulsifier, and the structure is:

[0031]

[0032] Wherein R1 is a nonylphenol group or a fatty alcohol group, R2 is an alkyl group of 1 to 6 C, X is an integer of 0, 10 to 50 or 10 to 30, and Y is an integer of 0, 10 to 50 or 10 to 30. The preferred preparation method is:

[0033] 1 mol of polyoxyethylene ether is placed in a reactor and heated to 100° C. Then 2 mol of sodium methoxide is slowly added, reacted for 3 hours (nitrogen is blown after half an hour), the material is cooled to below 60° C., 2.5 mol of n-butyl bromide is slowly added, after the n-butyl bromide is added, the temperature is raised to 100° C., and the reaction is continued for 3 hours to obtain a crude product. 5% of the quality of the crude product and a corresponding amount of phosphoric acid are added to the crude product, stirred at 90° C. for 1 hour, the pH value is adjusted to 4.8-5.2, 0.1% of the quality of the crude product is added with magnesium silicate, dehydrated to make its water content less than 0.05%, filtered, and the surfactant is obtained.

[0034] Based on the same inventive concept, the present invention also provides the use of the above-mentioned oil agent for carbon fiber in the production of polyacrylonitrile-based carbon fiber.

[0035] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0036] (1) The carbon fiber oil provided by the present invention The carbon fiber oil provided by the present invention includes amino-modified silicone oil and epoxy-modified silicone oil, and the chemical structure of the amino-modified silicone oil and the epoxy-modified silicone oil is a comb-shaped structure, wherein the main chain is an acrylate structure chain, and the side chains are short silane chains containing epoxy groups or amino groups. The short side chain structure can make the oil have low viscosity and good rheological properties when used, and can quickly wet the surface of the carbon fiber raw yarn to achieve rapid fiber coating and form a protective film on the fiber yarn to prevent friction and wear between the yarns, thereby reducing the surface defects of the carbon fiber. At the same time, it has good fiber separation and is not easy to stick.

[0037] (2) The carbon fiber oil of the present invention includes amino-modified silicone oil and epoxy-modified silicone oil compounded in proportion, which can synergistically improve the application performance of the oil product. Although the oil has a small molecular weight and low viscosity when used at room temperature, the epoxy groups and amino groups on the two modified silicone oils will react chemically at high temperatures to form a super-large molecular oil network coated on the fiber surface, thereby better protecting the carbon fiber precursor.

[0038] (3) The carbon fiber oil provided by the present invention includes amino-modified silicone oil and epoxy-modified silicone oil, and the chemical structure of amino-modified silicone oil and epoxy-modified silicone oil is a comb-shaped structure, wherein the main chain is an acrylate structure chain, and the side chain is a short silane chain containing epoxy or amino groups, respectively. The oil introduces an acrylate polymer, which can reduce the silicon content in the oil, and the silane chain is well dispersed in the molecular structure of the oil. Reducing the silicon content can avoid residue on the carbon fiber, and then avoid the silicon remaining on the carbon fiber to generate silicon oxide, silicon nitride and other substances under high-temperature carbonization conditions, thereby avoiding reducing the tensile strength of the carbon fiber; the oil with low silicon content has low pollution to the carbon fiber and carbonization equipment, which helps to keep the equipment clean and run efficiently, and reduce the frequency and cost of maintenance and cleaning; the oil with low silicon content can improve the quality of carbon fiber precursor, such as reducing the amount of hairiness, improving the bundling, etc., which helps to improve the performance and appearance quality of the final product; the use of low silicon oil can also reduce dependence on imported products, thereby reducing production costs.

[0039] At the same time, the present invention introduces acrylic polymer and non-ionic emulsifier into the oil agent, which will be cracked into small molecules such as CO2 and H2O that are easy to remove during the high-temperature carbonization and graphitization process of carbon fiber, which is beneficial to improve the mechanical properties of carbon fiber and reduce and avoid carbon fiber structural defects caused by the formation of "silicon-based ceramics" in carbon fiber.

[0040] (4) The preparation method of the carbon fiber oil provided by the present invention can obtain an amino-modified silicone oil emulsion with a comb-shaped structure and an epoxy-modified silicone oil emulsion. The emulsifier with a specific structure of the present application is used, and its terminal hydroxyl group has been blocked with an ester group, which has good high-temperature stability; at the same time, the use of ester groups to block the terminal hydroxyl groups can make the emulsifier itself have better smoothness, which is beneficial to ensure the smooth progress of the carbon fiber preparation process and improve the quality of the final product. DETAILED DESCRIPTION

[0041] The following is a further detailed description of an oil agent for carbon fiber and its preparation method and application proposed by the present invention in conjunction with specific embodiments. The advantages and features of the present invention will become more apparent from the following description.

[0042] Example 1

[0043] S1: Preparation of acrylate prepolymer

[0044] First, add 50g of butyl acrylate, 50g of isooctyl acrylate, 0.8g of dodecyl mercaptan, and 25g of methacryloyloxypropylmethyldimethoxysilane to 350g of toluene and mix them evenly; at the same time, dissolve 1.1g of initiator benzoyl peroxide in 50g of toluene to obtain an initiator solution; then heat to 80°C in an inert atmosphere, add 1 / 5 of the initiator solution, react for 0.5 hours, then add the remaining initiator, and continue to react for 5 hours. Finally, the obtained product liquid is distilled under reduced pressure at a pressure of 0.3MPa and a temperature of 90°C for 40min to remove the solvent to obtain an acrylate prepolymer.

[0045] S2: Preparation of amino-modified silicone oil emulsion

[0046] First, 0.6 g of tetramethylammonium hydroxide was dissolved in 6 g of deionized water, and then added together with 19.1 g of octamethylcyclotetrasiloxane linear body, 50 g of acrylate prepolymer, and 18 g of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser, and a thermometer. After stirring evenly, the mixture was reacted at 100° C. for 2.5 hours, and then 38.3 g of octamethylcyclotetrasiloxane linear body and 0.4 g of hexamethyldisiloxane were slowly added dropwise, and the reaction was continued for 4.5 hours. Then, 0.8 g of hexamethyldisiloxane was added and reacted for 1.5 hours. After cooling, a uniform translucent viscous liquid was obtained, which was the synthesized amino-containing short-chain silicone oil.

[0047] Then add 2.5g of emulsifier and 500g of water, stir and mix, adjust the pH value to neutral, raise the temperature to 80°C, and stir for 1 hour to obtain an amino-modified silicone oil emulsion.

[0048] S3: Preparation of epoxy-modified silicone oil emulsion

[0049] First, 0.7 g of tetramethylammonium hydroxide was dissolved in 4.3 g of deionized water, and then added together with 16.7 g of octamethylcyclotetrasiloxane linear body, 55 g of acrylate prepolymer, and 20 g of 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser, and a thermometer. After stirring evenly, the mixture was reacted at 110° C. for 2 hours, and then 33.4 g of octamethylcyclotetrasiloxane linear body and 0.7 g of hexamethyldisiloxane were slowly added dropwise, and the reaction was continued for 4 hours. Then, 1.3 g of hexamethyldisiloxane was added and reacted for 1 hour. After cooling, a uniform translucent viscous liquid was obtained, which was the synthesized epoxy-containing short-chain silicone oil.

[0050] Then, 2.5 g of emulsifier and 500 g of water were added, stirred and mixed, the pH value was adjusted to neutral, the temperature was raised to 80° C., and stirred for 1 hour to obtain an epoxy-modified silicone oil emulsion.

[0051] S4: Compound containing epoxy-modified silicone oil emulsion and amino-modified silicone oil emulsion

[0052] 1 kg of amino-modified silicone oil emulsion and 0.8 kg of epoxy-modified silicone oil emulsion were put into a container and stirred evenly to obtain an oil agent for carbon fiber.

[0053] Example 2

[0054] In this embodiment, steps S1-S3 are the same as those in embodiment 1, except that step S4 is:

[0055] S4: Compound containing epoxy-modified silicone oil emulsion and amino-modified silicone oil emulsion

[0056] 1 kg of amino-modified silicone oil emulsion and 1.4 kg of epoxy-modified silicone oil emulsion were placed in a container and stirred evenly to obtain an oil agent for carbon fiber.

[0057] Example 3

[0058] In this embodiment, step S1 is the same as in embodiment 1, and the other steps are different.

[0059] S2: Preparation of amino-modified silicone oil emulsion

[0060] First, 0.6 g of potassium hydroxide was dissolved in 6 g of deionized water, and then added together with 17.1 g of octamethylcyclotetrasiloxane linear body, 50 g of acrylate prepolymer, and 19 g of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser, and a thermometer. After stirring evenly, the mixture was reacted at 95° C. for 3 hours, and then 34.3 g of octamethylcyclotetrasiloxane linear body and 1 g of hexamethyldisiloxane were slowly added dropwise, and the reaction was continued for 5 hours. Then, 2 g of hexamethyldisiloxane was added and reacted for 1.5 hours. After cooling, a uniform translucent viscous liquid was obtained, which was the synthesized amino-containing short-chain silicone oil.

[0061] Then add 2.5g of emulsifier and 500g of water, stir and mix, adjust the pH value to neutral, heat to 85°C, stir for 1 hour, and obtain amino-modified silicone oil emulsion

[0062] S3: Preparation of epoxy-modified silicone oil emulsion

[0063] First, 5 g of 0.6 g of potassium hydroxide was dissolved in deionized water, and then added together with 17.8 g of octamethylcyclotetrasiloxane linear body, 50 g of acrylate prepolymer, and 18 g of 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser, and a thermometer. After stirring evenly, the mixture was reacted at 105° C. for 2.5 hours, and then 35.5 g of octamethylcyclotetrasiloxane linear body and 0.8 g of hexamethyldisiloxane were added dropwise, and the reaction was continued for 4.5 hours. Then, 1.6 g of hexamethyldisiloxane was slowly added and reacted for 1.5 hours. After cooling, a uniform translucent viscous liquid was obtained, which was the synthesized epoxy-containing short-chain silicone oil.

[0064] Then, 2.5 g of emulsifier and 500 g of water were added, stirred and mixed, the pH value was adjusted to neutral, the temperature was raised to 75° C., and stirred for 1 hour to obtain an epoxy-modified silicone oil emulsion.

[0065] S4: Compound containing epoxy-modified silicone oil emulsion and amino-modified silicone oil emulsion

[0066] 1 kg of amino-modified silicone oil emulsion and 1 kg of epoxy-modified silicone oil emulsion were put into a container and stirred evenly to obtain an oil agent for carbon fiber.

[0067] Example 4

[0068] Steps S1-S3 in this embodiment are the same as those in Embodiment 3, except for step S4, which is specifically as follows:

[0069] 1 kg of amino-modified silicone oil emulsion and 0.8 kg of epoxy-modified silicone oil emulsion were put into a container and stirred evenly to obtain an oil agent for carbon fiber.

[0070] Comparative Example 1

[0071] The steps S1-S2 in this comparative example are the same as those in Example 1, and the oil agent contains only amino-modified silicone oil emulsion.

[0072] Comparative Example 2

[0073] The steps S1 and S3 in this comparative example are the same as those in Example 1, and the oil agent only contains epoxy-modified silicone oil emulsion.

[0074] The water used in the above embodiments or comparative examples is deionized water, and the emulsifier used in the above embodiments or comparative examples is isomeric tridecanol polyoxyethylene ether butyl ether prepared by using isomeric tridecanol polyoxyethylene ether (EO=7) as raw material and n-butyl bromide as end-capping agent. The specific preparation method is:

[0075] 1 mol of isomeric tridecanol polyoxyethylene ether is placed in a reactor and heated to 100° C. Then 2 mol of sodium methoxide is slowly added, reacted for 3 hours (nitrogen is blown after half an hour), the material is cooled to below 60° C., 2.5 mol of n-butyl bromide is slowly added, and after the n-butyl bromide is added, the temperature is raised to 100° C., and the reaction is continued for 3 hours to obtain a crude product. 5% of the quality of the crude product and a corresponding amount of phosphoric acid are added to the crude product, stirred at 90° C. for 1 hour, the pH value is adjusted to 4.8-5.2, 0.1% of the quality of the crude product is added, magnesium silicate is added, dehydrated to make its water content less than 0.05%, filtered, and the surfactant is obtained.

[0076] Table 1 records the data of the use process of the oils prepared in Examples 1-4 and commercially available products (silicone oils)

[0077]

[0078] As can be seen from Table 1, the main chains of the oils prepared in the examples are all acrylate structural chains, and the side chains are short silane chains containing epoxy groups or amino groups. The oils introduce acrylate polymers, which reduces the silicone content and the proportion of silicone, thereby reducing "silicon dust".

[0079] Table 2 lists the performance comparison between the oil prepared in the example and the commercially available product (silicone oil):

[0080]

[0081] As can be seen from Table 2, the oil prepared in the embodiment has a lower viscosity and better carbon fiber processability than commercially available silicone oil carbon fiber oil products, and the obtained carbon fiber has high mechanical properties. At the same time, the fiber separation is good during processing, it is not easy to stick together, and the carbon fiber has no burrs.

[0082] From the comparison between Comparative Examples 1 and 2 and the embodiment, it can be seen that the amino-modified silicone oil and the epoxy-modified silicone oil compounded in proportion can synergistically improve the application performance of the oil product, and the obtained carbon fiber is burr-free and has high strength.

[0083] The above is a detailed description of the implementation of the present invention in conjunction with specific embodiments, but the present invention is not limited to the above implementation. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. An oil agent for carbon fiber, characterized in that: It comprises amino-modified silicone oil emulsion and epoxy-modified silicone oil emulsion, wherein the mass ratio of the amino-modified silicone oil emulsion to the epoxy-modified silicone oil emulsion is 1:0.5-1.5; The structures of amino-modified silicone oil and epoxy-modified silicone oil are both comb-shaped, wherein the main chain of the amino-modified silicone oil is an acrylate polymer, and the side chains are short amino silane chains; the main chain of the epoxy-modified silicone oil is an acrylate polymer, and the side chains are short epoxy silane chains; The preparation method of the oil agent is as follows: firstly, an acrylate prepolymer is prepared by a solvent polymerization method, then an amino-modified silicone oil and an epoxy-containing modified silicone oil are prepared respectively, and finally they are emulsified in water respectively.

2. A method for preparing an oil agent for carbon fiber according to claim 1, characterized in that: The following steps are involved: S1: preparing acrylate prepolymer; S2: preparing amino-modified silicone oil and epoxy-modified silicone oil; S3: Amino-modified silicone oil and epoxy-modified silicone oil are emulsified and compounded according to the ratio.

3. The method for preparing an oil agent for carbon fiber according to claim 2, characterized in that: The preparation method of the acrylate prepolymer in step S1 is specifically as follows: S101: adding acrylate monomer, chain transfer agent dodecyl mercaptan, and silane coupling agent with double bonds into toluene and mixing evenly; S102: dissolving 0.1-2% of the mass of the acrylic acid monomer in an initiator in toluene to obtain an initiator solution; S103: In an inert atmosphere, heat the mixed solution of step S101 to 65-85° C., add 1 / 5 of the initiator solution, react for 0.5-1 hour, then add the remaining initiator solution, continue the reaction for 3-6 hours, and remove the solvent from the obtained product liquid to obtain an acrylate prepolymer.

4. The method for preparing an oil agent for carbon fiber according to claim 3, characterized in that: The mass ratio of the acrylic acid ester monomer, the silane coupling agent with double bonds, the chain transfer agent dodecyl mercaptan and toluene is 100:15-30:0.5-2:300-500.

5. The method for preparing an oil agent for carbon fiber according to claim 3, characterized in that: The silane coupling agent with double bonds includes at least one of methacryloxypropylmethyldimethoxysilane, methacryloxypropylmethyldiethoxysilane, vinylmethyldimethoxysilane or vinylmethyldiethoxysilane; The acrylic acid ester monomer includes at least one of butyl acrylate, isooctyl acrylate, butyl methacrylate, methyl methacrylate, isobutyl acrylate, isooctyl methacrylate or ethyl acrylate.

6. The method for preparing an oil agent for carbon fiber according to claim 2, characterized in that: The preparation of the amino-modified silicone oil in step S2 includes: taking the sum of the weight percentages of all raw material components as 100%, the raw materials used and their weight percentages are as follows: Add the aqueous solution of the strong alkaline catalyst together with 1 / 3 of octamethylcyclotetrasiloxane linear body, acrylate prepolymer and 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser and a thermometer, stir evenly, react at 90-110°C for 2-3 hours, then slowly add the remaining octamethylcyclotetrasiloxane linear body and 1 / 3 of the end-capping agent, continue to react for 3-6 hours, then add the remaining end-capping agent and react for 1-2 hours, and after cooling, obtain a uniform translucent viscous liquid to obtain an amino-modified silicone oil.

7. The method for preparing an oil agent for carbon fiber according to claim 2, characterized in that: The preparation of epoxy-containing modified silicon in step S2 includes: taking the sum of the weight percentages of all raw material components as 100%, the raw materials used and their weight percentages are as follows: Add the aqueous solution of the strong alkaline catalyst together with 1 / 3 of octamethylcyclotetrasiloxane linear body, acrylate prepolymer and 3-[(2,3)-epoxypropyloxy]propylmethyldimethoxysilane into a reaction device equipped with a stirrer, a reflux condenser and a thermometer, stir evenly, react at 90-110° C. for 2-3 hours, then slowly add the remaining octamethylcyclotetrasiloxane linear body and 1 / 3 of the end-capping agent, continue to react for 3-6 hours, then add the remaining end-capping agent and react for 1-2 hours, and after cooling, obtain a uniform translucent viscous liquid to obtain epoxy-modified silicone oil.

8. The method for preparing an oil agent for carbon fiber according to claim 6 or 7, characterized in that: The end-capping agent is hexamethyldisiloxane or pentamethyldisiloxane; the strong alkaline catalyst is any one of potassium hydroxide, sodium hydroxide or tetramethylammonium hydroxide or a mixed catalyst of any several of them.

9. The method for preparing an oil agent for carbon fiber according to claim 2, characterized in that: The step S3 specifically comprises: mixing the emulsifier and the amino-modified silicone oil or the epoxy-modified silicone oil in a weight ratio of (1-5):100 in deionized water, adjusting the pH value to neutral, heating to 60-85° C., and stirring for 1 hour to obtain an amino-modified silicone oil emulsion or an epoxy-modified silicone oil emulsion.

10. The method for preparing an oil agent for carbon fiber according to claim 9, characterized in that: The structure of the emulsifier is: Wherein R1 is a nonylphenol group or a fatty alcohol group, R2 is an alkyl group of 1 to 6 C, X is an integer of 0, 10 to 50 or 10 to 30, and Y is an integer of 0, 10 to 50 or 10 to 30.

11. Use of the oil agent for carbon fiber according to claim 1 in the production of polyacrylonitrile-based carbon fiber.

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