A self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof

Abstract

The present invention relates to a self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof, and belongs to the field of new material technology. The sizing agent is weighed according to the following weight parts: 5-25 parts of main slurry, 1-3 parts of self-lubricating nanoparticle additive, 1-5 parts of silane coupling agent, 2-5 parts of modified starch, 2-10 parts of softener, 2-10 parts of surfactant, and 100 parts of deionized water. The surface sizing treatment of the continuous alumina fibers by the sizing agent of the present invention can effectively reduce the friction coefficient, significantly improve its wear resistance, and give the fibers certain self-lubricating properties. At the same time, the breaking strength and shear performance of the brittle continuous alumina fibers are improved, and the fiber fuzz and broken wire phenomena are reduced, thereby improving the weavability of the alumina fibers. The raw materials of the sizing agent are easy to obtain and have stable performance. Water is used as a solvent, and no volatile organic matter is added, which is beneficial to environmental protection and has good biodegradability.

Description

Technical Field

[0001] The present invention relates to the technical field of new continuous inorganic ceramic fiber materials, and in particular to a self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof. Background Art

[0002] Continuous alumina fiber is a high-performance inorganic fiber with alumina (Al2O3) as its main component and containing a small amount of SiO2 and MgO. It is internationally recognized as a new generation of main materials for high-temperature resistant hot-end components. It has a melting point of up to 2050°C and has the characteristics of high surface activity, large elastic modulus, and strong resistance to chemical corrosion. Its single-filament tensile strength is extremely high and has good impact resistance. It can be used as a reinforcement material in large fiber-reinforced composite components. At the same time, high alumina has a high melting point, low thermal conductivity, and good insulation properties. It can still maintain its complete fiber form in 1650°C gas, which can meet the requirements of long-term "service" in high-temperature gas environments. It has a broad market in the manufacturing fields of aircraft engines, ship fuel gas turbines, and special-shaped large-structure support frames.

[0003] Among them, continuous alumina fiber three-dimensional fabric reinforced composites have stronger designability and excellent overall mechanical properties, and can be used in fields such as high-temperature resistant layered insulation materials, radomes at the end of missile heads, and antenna windows for hypersonic aircraft. However, continuous alumina fibers have disadvantages such as poor bundling, poor cohesion, high brittleness of single fibers, and poor flexibility. During the weaving process of fiber three-dimensional fabrics, frequent contact and friction between multiple layers of yarn cause yarn damage, making single fibers prone to breakage, resulting in fiber bundle splitting or even breakage, which not only reduces the mechanical properties of continuous alumina fibers, but also reduces their weaving efficiency. Therefore, some performance defects of continuous alumina fibers have affected their processability and limited the application range of the fibers.

[0004] Sizing agents play a very important role in the application of continuous fibers. Through appropriate sizing treatment, the bundles can be effectively gathered and the surface defects of the fibers can be compensated, thereby improving the wear resistance and bundle strength of the fibers, and further improving the weavability of the fibers. At present, only a few literatures have reported on the preparation methods of sizing agents that can improve the weavability of alumina fibers. For example, the invention patent CN110184821B "A kind of alumina fiber flexibility modifier and its preparation method" discloses an alumina fiber flexibility modifier, which makes the yarn breakage rate of brittle fibers ≤1.5% and the strength retention rate ≥95%; the invention patent CN107382372B "A special sizing agent for twisted alumina continuous fiber and its preparation method" discloses a sizing agent that can give alumina continuous fibers excellent flexibility, bundling, and lubricity, while protecting the mechanical properties of the alumina continuous fibers from loss. Invention patent CN111807870B, "A Wetting Agent for Improving the Aging Resistance of Continuous Alumina Fibers, Its Preparation Method, and Application," discloses a wetting agent that imparts aging resistance to the fibers, exhibits good mechanical properties, and improves fiber wear resistance. While meeting coating rate requirements, the fibers are relatively soft, meeting the requirements of subsequent textile processing. Improved weavability is mentioned, but the document lacks specific testing analysis or relevant data to support this conclusion.

[0005] In order to improve the weavability of continuous alumina fibers, the present invention adds a suitable self-lubricating additive and different formulas to the sizing agent to perform sizing treatment on the fibers. The wear resistance is characterized by observing the changes in the fiber friction coefficient and wear rate through friction testing. The improvement of the fiber weaving performance is judged by testing the breaking strength, shear strength and stiffness of the fibers. This method can effectively reduce the friction coefficient, further improve the wear resistance of the continuous alumina fibers, give the fibers certain self-lubricating properties, enhance their mechanical properties, and improve the weavability of the fibers. At the same time, the sizing materials in the sizing agent are all degradable, easy to mix evenly with water, have good film-forming properties, are environmentally friendly, are simple to prepare, can be sized at low temperatures, and are easy to desize. Summary of the Invention

[0006] In light of this, the present invention provides a method for preparing a self-lubricating sizing agent for improving the wear resistance of continuous alumina fibers. By controlling the dosage of different formulations, the desired sizing agent is obtained, effectively improving the wear resistance of brittle continuous alumina fibers while also enhancing breaking strength and shear performance, and reducing the occurrence of fuzzy and broken fibers, thereby comprehensively improving the weavability of the continuous alumina fibers during weaving. The sizing agent is readily available and has stable performance. It uses water as a solvent and does not contain any volatile organic compounds, which is environmentally friendly and biodegradable.

[0007] The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0008] A self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof, comprising the following steps:

[0009] (1) Weigh the following raw materials according to the following weight parts: 5-25 parts of main slurry, 1-3 parts of self-lubricating nanoparticle additive, 1-5 parts of silane coupling agent, 2-5 parts of modified starch, 2-10 parts of softener, 2-10 parts of surfactant, and 100 parts of deionized water.

[0010] (2) Add 5 to 25 parts by weight of the main slurry and 100 parts by weight of deionized water to a preparation container, and stir uniformly at a temperature of 95-100° C. and a stirring speed of 1000 r / min;

[0011] (3) Add 2 to 10 parts of surfactant, 2 to 10 parts of softener, 1 to 5 parts of silane coupling agent, and 2 to 5 parts of modified starch to the mixture of (2), and continue stirring at a temperature of 95-100° C. and a stirring speed of 1000 r / min until the mixture is fully dissolved. Allow the slurry to cool and set aside;

[0012] (4) Tungsten disulfide (WS2) self-lubricating additive nanoparticles are dissolved in water and prepared into a WS2 aqueous solution through ultrasound for a period of time.

[0013] (5) Adding thiolated polyethylene glycol (PEG-SH) to the above-mentioned nanoparticle aqueous solution, heating and stirring first, and then ultrasonically treating to obtain modified nanoparticles.

[0014] (6) The mixture was centrifuged at low speed to remove unreacted nanoparticles and the supernatant was collected.

[0015] (7) The collected supernatant was centrifuged again at high speed, the supernatant was discarded and washed with water to remove excess polymer.

[0016] (8) Finally, the product is vacuum dried to obtain the modified self-lubricating nanoparticle additive WS2-PEG.

[0017] (9) adding WS2-PEG to the prepared slurry and dispersing it by ultrasonication for a certain period of time to obtain a self-lubricating sizing agent;

[0018] (10) The prepared continuous alumina fibers are sizing treated using a special sizing device.

[0019] Preferably, the main slurry is one of waterborne polyurethane (WPU), water-soluble polyester and water-soluble polyacrylic acid, all of which are green, environmentally friendly and biodegradable.

[0020] Preferably, the silane coupling agent is one of 3-aminopropyltrimethoxysilane (KH-540), 3-aminopropyltriethoxysilane (KH-550) and γ-glycidoxypropyltrimethoxysilane (KH-560).

[0021] Preferably, the modified starch is one of oxidized starch and phosphate starch.

[0022] Preferably, the softener is one of polyethylene glycol-200, polyethylene glycol-400 and polyethylene glycol-600.

[0023] Preferably, the surfactant is one of carboxymethyl cellulose (CMC), dodecyltrimethylammonium chloride and Tween-80.

[0024] Preferably, the self-lubricating nanoparticle additive may also be molybdenum disulfide (MoS2) and graphene.

[0025] Preferably, in step (4) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the required ultrasonic time is 12 to 24 hours, and the concentration of the WS2 aqueous solution is 0.1 to 1 mg / mL.

[0026] Preferably, in step (5) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the amount of PEG-SH added is 10 to 50 mg, the heating and stirring temperature is 10 to 40°C, the ultrasonic time is 1 to 5 hours, the ultrasonic frequency is 20,000 to 25,000 Hz, and the ultrasonic temperature is 20 to 40°C.

[0027] Preferably, in step (6) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the speed of low-speed centrifugation is 1000-3000 rpm, and the time is 5-10 min.

[0028] Preferably, in step (7) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the speed of high-speed centrifugation is 13,000 to 16,000 rpm, and the time is 20 to 30 min.

[0029] Preferably, in step (8) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the vacuum drying temperature is 50 to 80°C.

[0030] Preferably, in step (9) of the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, the ultrasonic time is 5 to 10 minutes, the ultrasonic frequency is 20,000 to 25,000 Hz, and the ultrasonic temperature is 15 to 30°C.

[0031] The present invention provides a method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers. The sizing agent suitable for continuous alumina fibers is obtained by regulating the ratio of the slurry formula.

[0032] The self-lubricating nanoparticles used in the present invention can be defined as functional materials that reduce polymer friction. The unit cell structure of tungsten disulfide is composed of a tungsten (W) atomic network plane and a sulfur (S) atomic network plane overlapping each other above and below, forming a "sandwich" layered structure. Due to the high surface energy of the nanoparticles, they are easy to agglomerate in solution and have poor dispersibility in aqueous solution, which hinders their application in the field of liquid lubrication. The present invention performs an organic chemical modification on them and adopts thiol-containing polyethylene glycol grafted with sulfur (S) bonds to enable them to have excellent dispersion stability in aqueous solution. After modification, the self-lubricating nano additive of the present invention can be well dispersed in aqueous solution, and can also be well dispersed in aqueous slurry and maintain a stable state, so that the sizing is stable, the particles can be evenly dispersed on the fiber surface, and the agglomeration phenomenon is reduced. By sizing the continuous alumina fiber, the self-lubricating nanoparticles are loaded on the inside and outside of the fiber through the physical adsorption effect. The main slurry wraps the fiber due to its good film-forming property, so that the nanoparticles loaded on the fiber during use are not easy to fall off. When the fiber is subjected to friction, due to the weak van der Waals interaction between the nanoparticle layers, relative sliding easily occurs between the layers, resulting in a self-lubricating effect, which makes the fiber have a good self-lubricating effect, which is beneficial to the improvement of the fiber's wear resistance and the improvement of the fiber's weavability.

[0033] Compared with the prior art, the main advantages of the preparation method of the present invention are:

[0034] The present invention provides a self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof. The sizing treatment reduces the friction coefficient of the fibers, thereby effectively improving the wear resistance of the brittle continuous alumina fibers and giving them certain self-lubricating properties. At the same time, the fuzz and broken wire phenomena caused by fiber friction are improved, and the mechanical properties and processing properties of the fibers are improved, thereby improving the weavability and weaving efficiency of the continuous alumina fibers and the product quality of the alumina fabrics.

[0035] The present invention provides a self-lubricating sizing agent for improving the weavability of continuous alumina fibers and a preparation method thereof. The advantages are that the raw materials of the sizing agent are easily available, the preparation method is simple, the sizing agent is stable and uniform, and it is easier to form a film and adhere to the alumina fibers. At the same time, it is easy to desize and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is an infrared spectrum analysis diagram of the self-lubricating additive prepared in Example 1 of the present invention before and after modification;

[0037] FIG2 is a graph showing the change in friction coefficient of continuous alumina fibers prepared in (a) desizing, (b) Comparative Example 1 of the present invention, and (c) Example 1 of the present invention under 1000 friction cycles;

[0038] FIG3 is a surface hairiness diagram of the original continuous alumina fiber after friction;

[0039] FIG4 is a diagram of the surface hairiness of the continuous alumina fiber after friction prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. Technology and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and methods should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0042] In the following examples, the experimental methods without specific conditions are generally determined according to national standards. If there are no corresponding national standards, they are carried out in accordance with the general international standards or the standards proposed by relevant companies. Unless otherwise specified, all parts are by weight.

[0043] All fibers used in the present invention are single-strand fibers.

[0044] The raw materials described in the present invention are all existing commercially available raw materials. The specific information of some raw materials is as follows:

[0045] The silane coupling agents are KH-540, KH-550, and KH-560, which are from Shanghai Aladdin Biochemical Technology Co., Ltd.; the softeners are PEG-200, PEG-400, and PEG-600, and the surfactants are carboxymethyl cellulose (CMC), dodecyltrimethylammonium chloride, and Tween-80, all from Shanghai Myrel Chemical Technology Co., Ltd.; and the tungsten disulfide nanoparticles are from Nanjing Muke Nanotechnology Co., Ltd.

[0046] Example 1

[0047] The preparation method of the sizing agent in this embodiment comprises the following steps:

[0048] (1) Add 5 parts by weight of water-soluble polyurethane to 100 parts by weight of deionized water, and stir at a temperature of 95-100° C. and a stirring speed of 1000 r / min until uniform;

[0049] (2) adding 2 parts by weight of a CMC surfactant, 2 parts by weight of a PEG-200 softener, 2 parts by weight of a KH-540 silane coupling agent, and 2.5 parts by weight of oxidized starch to the mixture of (1), and continuously stirring at a temperature of 95-100° C. and a stirring speed of 1000 r / min until the mixture is fully dissolved;

[0050] (4) 1 part by weight of tungsten disulfide particles was dissolved in water and ultrasonicated for 12 h to prepare a 0.1 mg / mL WS2 aqueous solution.

[0051] (5) 10 mg of thiolated polyethylene glycol (PEG-SH) was added to the above WS2 aqueous solution, reacted at a temperature of 10°C and a stirring speed of 200 rpm for 3 h, and then ultrasonically treated at a temperature of 20°C and a frequency of 20,000 Hz for 1 h to obtain WS2-PEG.

[0052] (6) The WS2-PEG solution obtained above was centrifuged at 1000 rpm for 5 min to remove unreacted nanoparticles and collect the supernatant.

[0053] (7) The collected supernatant was centrifuged again at 13,000 rpm for 20 min, the supernatant was discarded and washed with water to remove excess polymer.

[0054] (8) Finally, the product was vacuum dried at 50 °C to obtain the self-lubricating additive WS2-PEG.

[0055] (9) WS2-PEG was added to the prepared slurry and ultrasonicated for 5 min to obtain a continuous alumina fiber self-lubricating sizing agent;

[0056] (10) The prepared continuous alumina fibers are sizing treated using a special sizing device.

[0057] Example 2

[0058] The preparation method of the sizing agent in this embodiment comprises the following steps:

[0059] (1) Add 15 parts by weight of water-soluble polyester to 100 parts by weight of deionized water, and stir at a temperature of 95-100° C. and a stirring speed of 1000 r / min until uniform;

[0060] (2) adding 6 parts by weight of Tween-80 surfactant, 6 parts by weight of PEG-400 softener, 4 parts by weight of KH-540 silane coupling agent and 5 parts by weight of oxidized starch to the mixture of (1), and continuously stirring at a temperature of 95-100° C. and a stirring speed of 1000 r / min until the mixture is fully dissolved;

[0061] (4) 2 parts by weight of tungsten disulfide particles were dissolved in water and ultrasonically treated for 18 h to prepare a 0.5 mg / mL WS2 aqueous solution.

[0062] (5) 30 mg of thiolated polyethylene glycol (PEG-SH) was added to the above WS2 aqueous solution, reacted at a temperature of 25°C and a stirring speed of 300 rpm for 3 h, and then ultrasonically treated at a temperature of 30°C and a frequency of 23000 Hz for 3 h to obtain WS2-PEG.

[0063] (6) The WS2-PEG solution obtained above was centrifuged at 2000 rpm for 10 min to remove unreacted nanoparticles and collect the supernatant.

[0064] (7) The collected supernatant was centrifuged again at 15,000 rpm for 30 min, the supernatant was discarded and washed with water to remove excess polymer.

[0065] (8) Finally, the product was vacuum dried at 70 °C to obtain the self-lubricating additive WS2-PEG.

[0066] (9) WS2-PEG was added to the prepared slurry and ultrasonicated for 7 min to obtain a continuous alumina fiber self-lubricating sizing agent;

[0067] (10) The prepared continuous alumina fibers are sizing treated using a special sizing device.

[0068] Example 3

[0069] The preparation method of the sizing agent in this embodiment comprises the following steps:

[0070] (1) Add 25 parts by weight of water-soluble polyacrylic acid to 100 parts by weight of deionized water, and stir uniformly at a temperature of 95-100° C. and a stirring speed of 1000 r / min;

[0071] (2) adding 10 parts by weight of a surfactant of dodecyltrimethylammonium chloride, 10 parts by weight of a PEG-600 softener, 4 parts by weight of a KH-560 silane coupling agent, and 2.5 parts by weight of a phosphate starch to the mixture of (1), and continuously stirring at a temperature of 95-100° C. and a stirring speed of 1000 r / min until the mixture is fully dissolved;

[0072] (4) 3 parts by weight of tungsten disulfide particles were dissolved in water and ultrasonically treated for 24 h to prepare a 1 mg / mL WS2 aqueous solution.

[0073] (5) 10 mg of thiolated polyethylene glycol (PEG-SH) was added to the above WS2 aqueous solution, reacted at a temperature of 40°C and a stirring speed of 500 rpm for 3 h, and then ultrasonically treated at a temperature of 40°C and a frequency of 25000 Hz for 5 h to obtain WS2-PEG.

[0074] (6) The WS2-PEG solution obtained above was centrifuged at 3000 rpm for 10 min to remove unreacted nanoparticles and collect the supernatant.

[0075] (7) The collected supernatant was centrifuged again at 16,000 rpm for 30 min, the supernatant was discarded and washed with water to remove excess polymer.

[0076] (8) Finally, the product was vacuum dried at 80 °C to obtain the self-lubricating additive WS2-PEG.

[0077] (9) WS2-PEG was added to the prepared slurry and ultrasonicated for 10 min to obtain a continuous alumina fiber self-lubricating sizing agent;

[0078] (10) The prepared continuous alumina fibers are sizing treated using a special sizing device.

[0079] Comparative Example 1

[0080] To further illustrate the wear resistance of the sizing agent of the present invention on continuous alumina fibers after sizing, comparative examples are provided based on the above examples. The continuous alumina fibers of Comparative Examples 1-3 are prepared based on Examples 1-3, except that the WS2 nanoparticles prepared in steps 4-9 are removed.

[0081] Comparative Example 2

[0082] To further illustrate the flexibility of the continuous alumina fibers after sizing with the sizing agent of the present invention, comparative examples were prepared based on the above examples. The continuous alumina fibers of comparative examples 4-6 were prepared based on examples 1-3, except that the softener in step 2 was removed.

[0083] Comparative Example 3

[0084] To further illustrate the shear performance of the continuous alumina fibers after sizing with the sizing agent of the present invention, comparative examples were prepared based on the above examples. The continuous alumina fibers of Comparative Examples 7-9 were prepared based on Examples 1-3, except that the surfactant in preparation step 2 was removed.

[0085] To compare the technical advantages of this technical solution, the continuous alumina fibers used in Examples 1-3 and Comparative Examples 1-9 were subjected to a high-temperature desizing treatment, sizing, and then wound through a winding device and paper drum to obtain sized continuous alumina fibers. (The drying oven was 1 m long, the drying temperature was 110-150°C, and the drying speed was the same as the wire feed speed, both 2.0-5.0 m / min.) The sizing rate was then tested using a high-temperature calcination method, and the sized samples were tested for shear performance, tensile properties, stiffness, and wear resistance. The data obtained are shown in Table 1.

[0086] Stiffness is a reference value for the flexibility of continuous alumina fibers. A higher stiffness value indicates a lower flexibility, a weaker ability to adapt to bending deformation during weaving, and a greater susceptibility to damage during weaving. The wear rate measures the weight loss of continuous alumina fibers after a certain number of friction cycles, providing a reference value for the wear resistance of continuous alumina fibers during weaving. Shear performance refers to the force applied to the fiber perpendicular to its surface. A higher shear strength indicates a better bending resistance, thereby improving weaving efficiency and fiber weavability.

[0087] The tensile strength at break was tested by preparing continuous alumina fiber bundle tensile specimens according to GB / T3362-2005.

[0088] The test basis for stiffness is: GB / T 7690.4-2013 Test methods for reinforcing yarns Part 4: Determination of stiffness.

[0089] Shearing Performance Test: A shearing fixture is designed based on the shearing characteristics of the sewing thread. Procedure: Take a 50cm continuous alumina fiber sample, secure one end, and pass the other end through a hole in the fixture. A 100g weight controls the tension, and the sewing thread is cut by moving the upper fixture.

[0090] The shear strength was tested using a simple homemade shear test device.

[0091] The test basis for the wear rate is: FZ / T 01058-1999 Test method for abrasion resistance of yarn - reciprocating grinding roller method.

[0092] Coefficient of Friction (COF) testing: A UMT-Tribolab friction and wear tester was used. A custom fixture was used to secure the upper and lower fibers, positioning them perpendicular to each other (a technique known as the cross-cross method). The results were then read.

[0093] Table 1 Performance test results of continuous alumina fibers before and after sizing

[0094]

[0095] Relevant tests and analyses were carried out on Example 1, and the following analysis was obtained from the test results: the infrared spectrum analysis of Figure 1 showed that the relevant characteristic peaks of polyethylene glycol appeared on the modified nanoparticles, indicating that polyethylene glycol was successfully grafted onto the tungsten disulfide nanoparticles; the fiber was subjected to a cyclic friction test, and it can be seen from Figure 2 that the change in the fiber friction coefficient after desizing is extremely unstable, and the fiber friction coefficient after WPU sizing becomes relatively stable with the increase in the number of cycles. When the fiber is sizing with the sizing agent prepared by the present invention, its friction coefficient decreases while changing stably, so the self-lubricating property of the fiber after sizing is confirmed; it can be seen from Figures 3 and 4 that after a certain number of frictions, a large amount of hairiness is generated on the fiber surface, and the continuous alumina fiber sized with the sizing agent of the present invention has less hairiness on the fiber surface after the friction test, and the surface hairiness and broken fibers are improved.

[0096] The present invention uses sizing agents with different slurry ratios to treat continuous alumina fibers, thereby improving the wear and breakage of continuous alumina fibers during production and processing. The test results in the table show that, compared with the original continuous alumina fibers, at a sizing rate of 1% to 2%, the fiber wear rate is reduced by 20% to 24.21%, the friction coefficient is reduced by 28.95% to 31.1%, and the wear resistance is significantly improved, achieving self-lubricating properties to a certain extent. The shear and tensile properties of the fibers are significantly improved, by 33.1% to 41.9% and 43.49% to 46.47%, respectively. It is also found that sizing has little effect on the softness of the fibers. Compared with the continuous palladium oxide fibers prepared in comparative examples 1-3 in which WS2 nanoparticles are not added to the sizing agent, the wear rate and friction coefficient of the continuous alumina fibers prepared in embodiments 1-3 in which WS2 nanoparticles are added are significantly reduced, and the wear resistance is improved, which helps to improve the phenomenon of fiber damage or even breakage caused by frequent friction during weaving of the continuous alumina fibers; compared with the continuous alumina fibers prepared in comparative examples 4-6 in which no softener is added to the sizing agent, the stiffness of the continuous alumina fibers prepared in the embodiments after adding the softener is reduced, which helps to improve the fiber damage caused by bending deformation during weaving of the continuous alumina fibers; compared with the continuous alumina fibers prepared in comparative examples 7-9 in which no surfactant is added to the sizing agent, the shear strength of the continuous alumina fibers prepared in embodiments 1-3 in which a surfactant is added is improved, which helps to improve the fiber breakage caused by bending during weaving of the continuous alumina fibers. Therefore, the sizing agent used in the present invention can effectively protect the fibers under the premise of low sizing rate and without destroying the softness of the fibers, and at the same time give the fibers certain self-lubricating properties, thereby reducing the friction damage caused by the continuous alumina fibers during the weaving process, and improving the weavability of the fibers.

[0097] The above is only a preferred embodiment of the present invention, but it is not a limitation of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers, characterized in that The method comprises the following steps: (1) Weigh the following raw materials according to the following weight parts: 5-25 parts of main slurry, 1-3 parts of self-lubricating nanoparticle additive WS2-PEG, 1-5 parts of silane coupling agent, 2-5 parts of modified starch, 2-10 parts of softener, 2-10 parts of surfactant, and 100 parts of deionized water; (2) Add 5 to 25 parts by weight of the main slurry and 100 parts by weight of deionized water to a preparation container, and stir uniformly at a temperature of 95-100° C. and a stirring speed of 1000 r / min; (3) Add 2 to 10 parts of surfactant, 2 to 10 parts of softener, 1 to 5 parts of silane coupling agent, and 2 to 5 parts of modified starch to the mixture of (2), and continue stirring at a temperature of 95-100° C. and a stirring speed of 1000 r / min until the mixture is fully dissolved. Allow the slurry to cool and set aside; (4) dissolving tungsten disulfide (WS2) self-lubricating additive nanoparticles in water and preparing a WS2 aqueous solution through ultrasound for a period of time; (5) adding thiolated polyethylene glycol (PEG-SH) to the above-mentioned aqueous solution of nanoparticles, heating and stirring, and then ultrasonically treating to obtain modified nanoparticles; (6) centrifuging the mixture at low speed to remove unreacted nanoparticles and collecting the supernatant; (7) After the collected supernatant is centrifuged again at high speed, the supernatant is discarded and washed with water to remove excess polymer; (8) Finally, the product is vacuum dried to obtain the modified self-lubricating nanoparticle additive WS2-PEG; (9) adding WS2-PEG to the prepared slurry and dispersing it by ultrasonication for a certain period of time to obtain a self-lubricating sizing agent; (10) The prepared continuous alumina fibers are sizing treated using a special sizing device; (11) The softener is one of polyethylene glycol-200 (PEG-200), polyethylene glycol-400 (PEG-400) and polyethylene glycol-600 (PEG-600); (12) The surfactant is one of carboxymethyl cellulose (CMC), dodecyltrimethylammonium chloride and Tween-80.

2. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: The main slurry is one of waterborne polyurethane (WPU), water-soluble polyester and water-soluble polyacrylic acid, all of which are green, environmentally friendly and biodegradable.

3. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: The silane coupling agent is one of 3-aminopropyltrimethoxysilane (KH-540), 3-aminopropyltriethoxysilane (KH-550) and γ-glycidyloxypropyltrimethoxysilane (KH-560).

4. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, wherein: The modified starch is one of oxidized starch and phosphate starch.

5. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (4), the required ultrasonic time is 12 to 24 hours, and the concentration of the nanoparticle aqueous solution is 0.1 to 1 mg / mL.

6. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (5), the amount of PEG-SH added is 10-50 mg, the heating and stirring temperature is 10-40° C., the stirring speed is 200-500 rpm, the stirring time is 3-6 h, the ultrasonic time is 1-5 h, the ultrasonic frequency is 20000-25000 Hz, and the ultrasonic temperature is 20-40° C.

7. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (6), the low-speed centrifugation speed is 1000-3000 rpm, and the time is 5-10 min.

8. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (7), the speed of high-speed centrifugation is 13000-16000 rpm, and the time is 20-30 min.

9. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (8), the vacuum drying temperature is 50-80°C.

10. The method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to claim 1, characterized in that: In the step (9), the ultrasonic time is 5 to 10 minutes, the ultrasonic frequency is 20,000 to 25,000 Hz, and the ultrasonic temperature is 15 to 30°C.

11. A sizing agent obtained by the method for preparing a self-lubricating sizing agent for improving the weavability of continuous alumina fibers according to any one of claims 1 to 10.

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