A continuous silicon carbide fiber sizing agent and its application

Abstract

The present invention discloses a continuous silicon carbide fiber sizing agent and its application. The continuous carbonized fiber sizing agent comprises the following components by weight: 80-100 parts of water, 5-20 parts of waterborne polyurethane modified epoxy resin, 0.3-3 parts of acrylate modified polyurethane, 0.2-2 parts of emulsifier, and 0.2-2 parts of softener. The continuous carbonized fiber sizing agent provided by the present invention adopts waterborne polyurethane modified epoxy resin and acrylate modified polyurethane in combination. During the sizing process of the continuous carbonized fiber, the waterborne polyurethane modified epoxy resin and the acrylate modified polyurethane undergo a cross-linking reaction during drying. Due to the presence of cross-linking points between fibers, the fiber filaments and hair balls can be flattened, the bonding force between fibers is improved, and the monofilament fibers are inhibited from being separated from the fiber bundle, thereby reducing the hair balls and the amount of filaments, thereby improving the bundling and wear resistance.

Description

Technical Field

[0001] The invention relates to a silicon carbide fiber sizing agent, in particular to a continuous silicon carbide fiber sizing agent and application thereof. Background Art

[0002] Silicon carbide fibers prepared by the precursor method have the characteristics of high strength, high modulus, high temperature resistance, oxidation resistance, and low density. They have great application potential in the aerospace field and are key materials for improving the operating temperature and thrust-to-weight ratio of aircraft engines. However, in the process of processing one-dimensional silicon carbide fibers into two-dimensional or multi-dimensional silicon carbide fiber-reinforced composite materials, the fibers need to be woven. Since silicon carbide fibers are brittle materials, have low elongation at break, low elasticity, and the strength of the fiber bundle decreases with the increase of fiber length, during the weaving process, when the fibers and the yarn frame rub against each other, it is easy for single filaments to break, resulting in a large number of hairs or even breaks in the fiber bundle, which reduces the performance of the silicon carbide fiber braid. This not only affects the weaving efficiency of silicon carbide fibers, but also seriously reduces the product quality of silicon carbide fabrics.

[0003] In order to improve the weaving of silicon carbide fiber, the fiber must be sized. Huang Xiangxian et al. (CN109853268A) used PVA (polyvinyl alcohol) as the main sizing agent, which has good film-forming property and strong cohesiveness, can well bond the fiber bundles tightly together, has very good bundling property, greatly reduces fiber hairs, and increases wear resistance, but has the problem of improved fiber stiffness and poor flexibility. Zhang Xinyuan et al. (CN111704478B) proposed a sizing method for high-strength and high-modulus silicon carbide fiber, which prepares sizing agent with deionized water, epoxy resin slurry and hydrophilic softener in a certain proportion, epoxy resin and hydrophilic softener ensure the flexibility of fiber after sizing, and avoid the situation that fiber is too stiff and brittle when weaving, but it is lacking in bundling property, and no emulsifier is added to the system, resulting in problems in the long-term storage and stability of the sizing agent. Zong Sheng et al. (CN110172829A) used water-based polyurethane as the main slurry to prepare a sizing agent, which effectively improved the softness of the slurry film on the surface of silicon carbide fiber bundles, and improved the fiber's bundling, wear resistance, and strength and elongation. However, toxic organic substances such as ketones and amines were used as additives, posing a certain threat to personal safety. Summary of the invention

[0004] In view of the above problems, the first object of the present invention is to provide a continuous carbonized fiber sizing agent. The raw materials of the sizing agent of the present invention are all environmentally friendly substances, non-toxic, and convenient for industrial mass production.

[0005] The second object of the present invention is to provide an application of a continuous carbonized fiber sizing agent. After the continuous carbonized fiber sizing agent is used to size the continuous carbonized fiber, the sized fiber not only has good bundling and wear resistance, but also has very good flexibility, which can effectively solve the problem of hair and breakage that are easy to generate during the weaving process.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The invention discloses a continuous carbonized fiber sizing agent, which comprises the following components by weight: 80-100 parts of water, 5-20 parts of waterborne polyurethane modified epoxy resin, 0.3-3 parts of acrylate modified polyurethane, 0.2-2 parts of emulsifier and 0.2-2 parts of softener.

[0008] The continuous carbonized fiber sizing agent provided by the present invention adopts a water-based polyurethane modified epoxy resin and an acrylate modified polyurethane in combination. The inventors have found that if the water-based polyurethane modified epoxy resin is used alone, the fibers after sizing are very smooth, but the bundling property is poor and there are many fiber fuzzes. When the acrylate modified polyurethane is introduced into the obtained continuous carbonized fiber sizing agent, during the sizing process of the continuous carbonized fiber, when drying, the water-based polyurethane modified epoxy resin and the acrylate modified polyurethane undergo a cross-linking reaction. Due to the presence of cross-linking points between the fibers, the fiber fuzzes and hair balls can be flattened, the bonding force between the fibers is improved, and the single filament fibers are inhibited from being separated from the fiber bundle, thereby reducing the hair balls and the amount of hair, thereby improving the bundling property and wear resistance.

[0009] During the experimental exploration process, the inventor tried a large number of formulas. Even for modified polyurethane, in addition to acrylate-modified polyurethane, the inventor also tried silicone-modified polyurethane, organic fluorine-modified polyurethane, etc. The result showed that only when acrylate-modified polyurethane and water-based polyurethane-modified epoxy resin were matched with each other, the bundling and wear resistance were optimal. In addition, acrylate-modified polyurethane also has the characteristics of strong hydrophilicity and good stability, making the continuous carbonized fiber sizing agent more uniform and stable.

[0010] Of course, the amount of acrylate-modified polyurethane added needs to be effectively controlled. If too much acrylate-modified polyurethane is added, the fiber after sizing will be too stiff and have poor flexibility, which is not conducive to weaving. Adding too little will lead to poor fiber bundling after sizing, which will easily produce hair during weaving.

[0011] In a preferred embodiment, the continuous carbonized fiber sizing agent comprises the following components, calculated by weight: 80-100 parts of water, 5-15 parts of waterborne polyurethane modified epoxy resin, 0.7-1 part of acrylate modified polyurethane, 0.3-0.6 parts of emulsifier, and 0.6-1.2 parts of softener.

[0012] Further preferably, the continuous carbonized fiber sizing agent has the following components, calculated by weight: 80-90 parts of water, 10-15 parts of waterborne polyurethane modified epoxy resin, 0.7-0.8 parts of acrylate modified polyurethane, 0.6 parts of emulsifier, and 0.8-1.2 parts of softener.

[0013] Preferably, the water is deionized water.

[0014] In a preferred embodiment, the waterborne polyurethane modified epoxy resin is a waterborne polyurethane modified bisphenol A type epoxy resin.

[0015] In a preferred embodiment, the preparation process of the waterborne polyurethane modified epoxy resin is as follows: waterborne polyurethane, bisphenol A epoxy resin, and dibutyltin diacetate are uniformly stirred in a mass ratio of 70-85:15-30:0.01-0.05, then the mixture is heated to 75-100° C. and kept warm for 2-5 hours, and then cooled to obtain the waterborne polyurethane modified epoxy resin.

[0016] Further preferably, the preparation process of the waterborne polyurethane is: polyethylene glycol (PEG), diisocyanate, and dihydroxyacetic acid are uniformly stirred in a mass ratio of 50-70:30-40:5-10, heated to 60-80° C. and kept warm for 2-5 hours, and cooled to obtain the waterborne polyurethane.

[0017] The waterborne polyurethane modified epoxy resin provided by the present invention has good water solubility, does not need to use an organic solvent, and can be well stably present as the main component of a sizing agent without stratification. This is mainly because in the process of preparing the waterborne polyurethane, the present invention adds a hydrophilic group, which can be better dissolved in water and is stable, thereby avoiding the problem that the unmodified polyurethane has poor water solubility and is difficult to dissolve in the sizing agent, resulting in uneven sizing agent.

[0018] In a preferred embodiment, the emulsifier is alkylphenol polyoxyethylene ether (TX-10) or octylphenol polyoxyethylene ether (OP-10). The emulsifier used in the present invention has high chemical stability, is easily soluble in water, has excellent emulsifying ability, and has a static electricity removal effect.

[0019] In a preferred embodiment, the softener is polyether amino block modified silicone oil.

[0020] In the actual operation process, the model of polyether amino block modified silicone oil that can be selected is NE 810 or NE820. The inventors found that polyether amino block modified silicone oil, as the fourth generation softener, not only has the very excellent softening effect of amino modified silicone oil, but the introduced polyether segment greatly improves its hydrophilicity, plays a self-emulsifying effect, and will not cause demulsification.

[0021] According to a preferred solution, the preparation process of the continuous carbonized fiber sizing agent is as follows: water, water-based polyurethane-modified epoxy resin, acrylate-modified polyurethane, emulsifier, and softener are mixed and stirred evenly according to the designed proportions to obtain the continuous carbonized fiber sizing agent.

[0022] The present invention also provides an application of a continuous carbonized fiber sizing agent, wherein the continuous carbonized fiber sizing agent is used for sizing carbonized fibers, and the sizing process is as follows: silicon carbide fibers are soaked in the continuous carbonized fiber sizing agent to obtain silicon carbide fibers wrapped with the sizing agent, and then the silicon carbide fibers wrapped with the sizing agent are dried at 150-250° C. to obtain sized silicon carbide fibers.

[0023] In the application process of the present invention, after obtaining the silicon carbide fiber wrapped with the sizing agent, the silicon carbide fiber wrapped with the sizing agent is dried at 150-250° C. In this process, water evaporates, and the remaining water-based polyurethane modified epoxy resin and acrylate modified polyurethane naturally become a layer of film attached to the fiber. At the specific temperature of the present invention, the water-based polyurethane modified epoxy resin and the acrylate modified polyurethane will undergo a cross-linking reaction, and the molecular weight will grow, so that the film can better bond the loose fibers together, thereby improving the bundling and wear resistance of the fibers after sizing.

[0024] In the present invention, the drying temperature needs to be effectively controlled. If the drying temperature is too high, the sizing agent will volatilize excessively and even undergo a cracking reaction. If the drying temperature is too low, it cannot be guaranteed to be dried at a normal sizing speed, causing the rolled fibers to stick together in the end.

[0025] Further preferably, the sizing process is to pass the silicon carbide fiber around the guide roller, and then pass it through a sizing tank containing a continuous carbon fiber sizing agent to make the silicon carbide fiber soaked in the continuous carbon fiber sizing agent to obtain silicon carbide fiber wrapped with the sizing agent. The silicon carbide fiber wrapped with the sizing agent continues to pass through a sizing roller, and then passes through an oven to dry at 150-250°C, and then is collected by a wire collecting machine at a speed of 1-3m / min to obtain sized silicon carbide fiber.

[0026] In the actual operation process, the guide roller, sizing trough and sizing roller are first cleaned to ensure that the surface is smooth and free of debris to prevent damage to the fiber, and then the oven is turned on, the temperature is raised to 150-250℃ and kept warm.

[0027] More preferably, the mixture is dried at 160-220°C.

[0028] More preferably, the mixture is dried at 200-220°C.

[0029] Principles and advantages

[0030] 1. The continuous silicon carbide fiber sizing agent provided by the present invention can effectively solve the problem of difficulty in weaving high-strength and high-modulus silicon carbide fibers. The use of the sizing agent can achieve coating of a layer of adhesive film on the surface of the silicon carbide fiber, make up for the cracks and defects on the silicon carbide fiber, and at the same time bond the loose silicon carbide fiber bundles together, greatly reducing the fuzz and improving the bundle strength and wear resistance.

[0031] 2. The present invention provides a continuous silicon carbide fiber sizing agent, which is a sizing agent prepared by combining water-based polyurethane modified epoxy resin and modified polyurethane, and can take into account both softness and bundling properties to obtain silicon carbide fibers with excellent weaving performance.

[0032] 3. The continuous carbonized fiber sizing agent provided by the present invention avoids the problem of fiber stiffness after sizing with PVA (polyvinyl alcohol) sizing agent, so that the fiber will not break brittlely due to bending; at the same time, it solves the problem of poor fiber bundle bundling after sizing with a simple epoxy resin sizing agent, reduces the hair in the weaving process, and greatly improves the weaving quality.

[0033] 4. The continuous carbonized fiber sizing agent provided by the present invention does not use organic reagents as solvents, is environmentally friendly and green, and the sizing agent is uniform and stable, can be stored for a long time without deterioration or stratification, does not contain elements that are corrosive to the fibers, can protect the fibers well, and the raw materials are cheap, simple and easy to obtain, the process equipment is simple, and can be used in large-scale industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the sizing process for silicon carbide fiber in the present invention.

[0035] In the figure, 1. silicon carbide fiber, 2. guide roller, 3. sizing tank, 4. squeezing roller, 5. oven, 6. silicon carbide fiber after sizing, 7. wire collecting machine. DETAILED DESCRIPTION

[0036] In order to better demonstrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] (1) Preparation of sizing agent

[0039] First, polyethylene glycol (PEG), diisocyanate, and dihydroxyacetic acid are stirred and mixed in a mass ratio of 50:40:6, then heated to 70°C and kept warm for 3 hours, and then cooled to obtain waterborne polyurethane. Then, waterborne polyurethane, bisphenol A epoxy resin, and dibutyltin diacetate (catalyst) are stirred and mixed in a mass ratio of 70:30:0.02, and then heated to 80°C and kept warm for 5 hours, and then cooled to obtain waterborne polyurethane modified epoxy resin.

[0040] Deionized water, waterborne polyurethane modified epoxy resin, acrylate modified polyurethane, octylphenol polyoxyethylene ether (OP-10), and polyether amino block modified silicone oil (NE 810) were mixed and stirred uniformly in a mass ratio of 100:5:1:0.3:0.6 to prepare a continuous carbonized fiber sizing agent for use.

[0041] (2) Preparation before sizing

[0042] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 160°C and keep it warm.

[0043] (3) Sizing

[0044] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the squeezing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 3m / min to obtain the sized silicon carbide fiber 6.

[0045] Example 2

[0046] (1) Preparation of sizing agent

[0047] Polyethylene glycol (PEG), diisocyanate and dihydroxyacetic acid are stirred and mixed in a mass ratio of 60:30:10, then heated to 80°C and kept warm for 2 hours, and then cooled to obtain water-based polyurethane. Then, bisphenol water-based polyurethane, type A epoxy resin and dibutyltin diacetate (catalyst) are stirred and mixed in a mass ratio of 75:25:0.03, and then heated to 100°C and kept warm for 2 hours, and then cooled to obtain water-based polyurethane modified epoxy resin.

[0048] Deionized water, waterborne polyurethane modified epoxy resin, acrylate modified polyurethane, alkylphenol polyoxyethylene ether (TX-10), and polyether amino block modified silicone oil (NE 810) are mixed and stirred evenly in a mass ratio of 90:10:0.8:0.6:0.8 to prepare a sizing agent for use.

[0049] (2) Preparation before sizing

[0050] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 200°C and keep it warm.

[0051] (3) Sizing

[0052] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the sizing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 2m / min to obtain the sized silicon carbide fiber 6.

[0053] Example 3

[0054] (1) Preparation of sizing agent

[0055] Polyethylene glycol (PEG), diisocyanate and dihydroxyacetic acid are stirred and mixed in a mass ratio of 65:36:7, then heated to 75°C and kept warm for 5 hours, and then cooled to obtain waterborne polyurethane. Then, waterborne polyurethane, bisphenol A epoxy resin and dibutyltin diacetate (catalyst) are stirred and mixed in a mass ratio of 80:15:0.05, then heated to 90°C and kept warm for 4 hours, and then cooled to obtain waterborne polyurethane modified epoxy resin.

[0056] Deionized water, water-based epoxy resin, acrylate-modified polyurethane, alkylphenol polyoxyethylene ether (TX-10), and polyether amino block modified silicone oil (NE 820) were mixed and stirred evenly in a mass ratio of 80:15:0.7:0.6:1.2 to prepare a sizing agent for use.

[0057] (2) Preparation before sizing

[0058] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 220°C and keep it warm.

[0059] (3) Sizing

[0060] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the sizing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 1m / min to obtain the sized silicon carbide fiber 6.

[0061] Comparative Example 1

[0062] (1) Preparation of sizing agent

[0063] Deionized water, polyvinyl alcohol (PVA), alkylphenol polyoxyethylene ether (TX-10), and polyether amino block modified silicone oil (NE 820) were mixed and stirred uniformly in a mass ratio of 80:2:0.6:1.2 to prepare a sizing agent for use.

[0064] (2) Preparation before sizing

[0065] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 250°C and keep it warm.

[0066] (3) Sizing

[0067] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the sizing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 1m / min to obtain the sized silicon carbide fiber 6.

[0068] It was found that although the fiber bundles after sizing have very good bundling properties, they are very stiff and have weak wear resistance, and they will break during weaving.

[0069] Comparative Example 2

[0070] (1) Preparation of sizing agent

[0071] First, polyethylene glycol (PEG), diisocyanate, and dihydroxyacetic acid are stirred and mixed in a mass ratio of 65:36:7, then heated to 75°C and kept warm for 5 hours, and then cooled to obtain waterborne polyurethane. Then, bisphenol A epoxy resin, waterborne polyurethane, and dibutyltin diacetate (catalyst) are stirred and mixed in a mass ratio of 80:15:0.05, and then heated to 90°C and kept warm for 4 hours, and then cooled to obtain waterborne polyurethane modified epoxy resin.

[0072] Deionized water, waterborne polyurethane modified epoxy resin, alkylphenol polyoxyethylene ether (TX-10), and polyether amino block modified silicone oil (NE 820) were mixed and stirred evenly in a mass ratio of 80:15:0.6:1.2 to prepare a sizing agent for use.

[0073] (2) Preparation before sizing

[0074] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 220°C and keep it warm.

[0075] (3) Sizing

[0076] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the sizing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 1m / min to obtain the sized silicon carbide fiber 6.

[0077] Comparative Example 3

[0078] (1) Preparation of sizing agent

[0079] Polyethylene glycol (PEG), diisocyanate and dihydroxyacetic acid are stirred and mixed in a mass ratio of 65:36:7, then heated to 75°C and kept warm for 5 hours, and then cooled to obtain waterborne polyurethane. Then, waterborne polyurethane, bisphenol A epoxy resin and dibutyltin diacetate (catalyst) are stirred and mixed in a mass ratio of 80:15:0.05, then heated to 90°C and kept warm for 4 hours, and then cooled to obtain waterborne polyurethane modified epoxy resin.

[0080] Deionized water, water-based epoxy resin, acrylate-modified polyurethane, alkylphenol polyoxyethylene ether (TX-10), and polyether amino block modified silicone oil (NE 820) are mixed and stirred evenly in a mass ratio of 80:15:5:0.6:1.2 to prepare a sizing agent for use.

[0081] (2) Preparation before sizing

[0082] Clean the guide roller 2, the sizing tank 3 and the sizing roller 4 to ensure that the surface is smooth and free of debris to prevent damage to the fiber, then turn on the oven 5, heat it to 220°C and keep it warm.

[0083] (3) Sizing

[0084] The silicon carbide fiber 1 is passed around the guide roller 2, and passes through the sizing tank 3, the sizing roller 4 and the oven 5 in sequence, and finally reaches the wire collecting machine 7, and then the sizing agent is poured into the sizing tank 3 to fully wet the silicon carbide fiber 1, and finally the wire is collected at a speed of 1m / min to obtain the sized silicon carbide fiber 6.

[0085] Performance comparison: According to the method in the literature (New Carbon Materials, 2006, 21(4): 337-341; Title: Heat-resistant carbon fiber emulsion sizing agent), the wear resistance and lint content of silicon carbide fibers in Examples 1-3 and Comparative Examples 1-2 were tested. The specific testing method is to use the hand-feel visual method to compare the bundle performance of silicon carbide fibers after sizing, and use the flexibility angle to characterize the flexibility of the fiber. The smaller the angle, the better the fiber flexibility. The flexibility angle testing method is: take a 30 cm long fiber bundle, place it on a rod-shaped object and let the fiber bundle droop naturally. At this time, the angle between the fiber bundles on both sides of the rod-shaped object is the flexibility angle. The obtained sizing carbon fiber performance evaluation results are shown in Table 1 below.

[0086] Table 1

[0087] Abrasion resistance / times Hair amount / mg Cluster Flexibility angle / ° Example 1 145 3.6 excellent 35 Example 2 163 2.8 excellent 40 Example 3 187 1.9 excellent 50 Comparative Example 1 109 1.5 excellent 120 Comparative Example 2 97 7.3 generally 30 Comparative Example 3 113 1.1 excellent 110

[0088] Comparative Example 1 uses polyvinyl alcohol (PVA) as the sizing agent of the main slurry. After sizing, the fiber bundle is too stiff, the wear resistance is weak, and the flexibility angle requirement is wide. Comparative Example 2 only uses water-based polyurethane modified epoxy resin as the sizing agent of the main slurry. After sizing, the fiber bundle has poor bundling and is prone to hair. However, the sizing agent prepared by the composite preparation of water-based polyurethane modified epoxy resin and modified polyurethane in the present invention can take into account both flexibility and bundling, and obtain silicon carbide fibers with excellent weaving performance. Comparative Example 3 uses too much acrylate modified polyurethane, which makes the fiber after sizing too stiff and has very poor flexibility, which is not conducive to improving weaving performance.

Claims

1. A continuous carbonized fiber sizing agent, characterized in that: The composition is as follows by weight: 80-100 parts of water, 5-20 parts of waterborne polyurethane modified epoxy resin, 0.3-3 parts of acrylate modified polyurethane, 0.2-2 parts of emulsifier, and 0.2-2 parts of softener; The waterborne polyurethane modified epoxy resin is a waterborne polyurethane modified bisphenol A type epoxy resin; The preparation process of the waterborne polyurethane modified epoxy resin is as follows: waterborne polyurethane, bisphenol A epoxy resin and dibutyltin diacetate are stirred and mixed evenly according to a mass ratio of 70-85:15-30:0.01-0.05, then heated to 75-100° C. and kept warm for 2-5 hours, and cooled to obtain the waterborne polyurethane modified epoxy resin; The preparation process of the waterborne polyurethane is as follows: polyethylene glycol, diisocyanate and dihydroxyacetic acid are uniformly mixed in a mass ratio of 50-70:30-40:5-10, heated to 60-80° C. and kept warm for 2-5 hours, and cooled to obtain the waterborne polyurethane; The softener is polyether amino block modified silicone oil.

2. The continuous carbonized fiber sizing agent according to claim 1, characterized in that: The continuous carbonized fiber sizing agent has the following components, calculated by weight: 80-100 parts of water, 5-15 parts of waterborne polyurethane modified epoxy resin, 0.7-1 part of acrylate modified polyurethane, 0.3-0.6 parts of emulsifier, and 0.6-1.2 parts of softener.

3. The continuous carbonized fiber sizing agent according to claim 1, characterized in that: The continuous carbonized fiber sizing agent has the following components, calculated by weight: 80-90 parts of water, 10-15 parts of waterborne polyurethane modified epoxy resin, 0.7-0.8 parts of acrylate modified polyurethane, 0.6 parts of emulsifier, and 0.8-1.2 parts of softener.

4. The continuous carbonized fiber sizing agent according to claim 1, characterized in that: The emulsifier is alkylphenol polyoxyethylene ether or octylphenol polyoxyethylene ether.

5. The continuous carbonized fiber sizing agent according to claim 1, characterized in that: The preparation process of the continuous carbonized fiber sizing agent is as follows: water, waterborne polyurethane modified epoxy resin, acrylate modified polyurethane, emulsifier and softener are mixed and stirred evenly according to the designed proportion to obtain the continuous carbonized fiber sizing agent.

6. The use of a continuous carbonized fiber sizing agent according to any one of claims 1 to 5, characterized in that: The continuous carbonized fiber sizing agent is used for sizing carbonized fibers. The sizing process is as follows: silicon carbide fibers are soaked in the continuous carbonized fiber sizing agent to obtain silicon carbide fibers wrapped with the sizing agent, and then the silicon carbide fibers wrapped with the sizing agent are dried at 150-250° C. to obtain sized silicon carbide fibers.

7. The use of a continuous carbonized fiber sizing agent according to claim 6, characterized in that: The sizing process is as follows: the silicon carbide fiber is passed around a guide roller, and then passed through a sizing tank containing a continuous carbon fiber sizing agent, so that the silicon carbide fiber is soaked in the continuous carbon fiber sizing agent to obtain the silicon carbide fiber wrapped with the sizing agent, and the silicon carbide fiber wrapped with the sizing agent continues to pass through a sizing roller, and then passes through an oven to dry at 150-250° C., and then is collected by a wire collecting machine at a speed of 1-3 m / min to obtain the sized silicon carbide fiber.

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