Composite material for stylus and preparation method thereof, stylus and preparation method thereof

Abstract

The application provides a composite material for a stylus pen and a preparation method thereof, a stylus pen and a preparation method thereof, components of the composite material for the stylus pen include plasma-phosphoric acid roughening modified aramid fiber bundle, epoxy resin, modified reduced graphite oxide, polytetrafluoroethylene, curing agent and plasticizer; wherein the mass ratio of the plasma-phosphoric acid roughening modified aramid fiber bundle, the epoxy resin, the soluble polytetrafluoroethylene and the modified reduced graphite oxide is (15-33):(5-14):(0.6-3.5):1. The composite material and the stylus pen prepared by the preparation method have the advantages of moderate hardness, small friction coefficient and small friction loss.

Description

Technical Field

[0001] This invention relates to the field of touch materials, and more particularly to a composite material for a stylus and its preparation method, as well as a stylus and its preparation method. Background Technology

[0002] Styluses, as an important accessory for interactive display products, have received widespread attention in the industry. Current stylus tips are made of materials such as metal, hard plastic, and soft rubber. While tips made of metal and hard plastic offer smooth writing, their rigidity results in loud impact noise on the screen, negatively affecting the user's writing experience and potentially damaging the screen with prolonged use. Tips made of soft rubber, while producing less impact noise, suffer from poor writing smoothness due to their higher damping. Furthermore, the tips are prone to deformation, leading to accidental touches, and rubber is not wear-resistant, resulting in a short lifespan. Therefore, stylus tips made from existing materials struggle to fully meet user needs and provide a satisfactory experience. Summary of the Invention

[0003] Based on the above situation, the main objective of this invention is to provide a composite material for a stylus with moderate hardness, low coefficient of friction and low friction loss, as well as a method for preparing the same, and a stylus and the method for preparing the same.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The present invention provides a composite material for a stylus, wherein the components of the composite material for the stylus include plasma-phosphoric acid roughened modified aramid fiber bundles, epoxy resin, modified reduced graphite oxide, soluble polytetrafluoroethylene, curing agent and plasticizer;

[0006] The mass ratio of the plasma-phosphoric acid roughened modified aramid fiber bundle, the epoxy resin, the soluble polytetrafluoroethylene and the modified reduced graphene oxide is (15-33):(5-14):(0.6-3.5):1.

[0007] Preferably, the component ratio of the composite material used for the stylus is:

[0008] The plasma-phosphate roughened modified aramid fiber bundle: 200-250 parts;

[0009] The epoxy resin: 80-100 parts;

[0010] The modified reduced graphite oxide: 8-12 parts;

[0011] The soluble polytetrafluoroethylene: 10-20 parts;

[0012] The curing agent: 30-45 parts;

[0013] The plasticizer: 6-10 parts.

[0014] The present invention also provides a method for preparing a composite material for a stylus, comprising:

[0015] Step S100: Place the aramid fiber bundle in a phosphoric acid solution to obtain a phosphoric acid-modified aramid fiber bundle; subject the phosphoric acid-modified aramid fiber bundle to low-temperature plasma treatment to obtain a plasma-modified phosphoric acid-modified aramid fiber bundle.

[0016] Step S200: Graphite oxidation treatment yields graphite oxide, the graphite oxide is modified to obtain modified graphite oxide, and the modified graphite oxide is reduced to obtain modified reduced graphite oxide.

[0017] Step S300: Mix epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide, and stir to obtain a mixture, wherein the mass ratio of epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide is (5-14):(0.6-3.5):1;

[0018] Step S400: Add curing agent and plasticizer to the mixture and stir to form an adhesive solution;

[0019] Step S500: Immerse the plasma-phosphate roughened modified aramid fiber bundle in the adhesive solution, and cure and foam the impregnated plasma-phosphate roughened modified aramid fiber bundle to obtain a composite material for stylus pen; wherein, the mass ratio of the plasma-phosphate roughened modified aramid fiber bundle to the modified reduced graphite oxide is (15-33):1.

[0020] Preferably, the allocation ratio of each group in the method is:

[0021] The plasma-phosphate roughened modified aramid fiber bundle: 200-250 parts;

[0022] The epoxy resin: 80-100 parts;

[0023] The modified reduced graphite oxide: 8-12 parts;

[0024] The soluble polytetrafluoroethylene: 10-20 parts;

[0025] The curing agent: 30-45 parts;

[0026] The plasticizer: 6-10 parts.

[0027] Preferably, in step 300, the epoxy resin is first dissolved in ethyl acetate, and then the soluble polytetrafluoroethylene and the modified reduced graphene oxide are added.

[0028] Before step S500, the mixture is placed in an oven and baked to remove the ethyl acetate;

[0029] The ethyl acetate is in the form of 60-150 parts.

[0030] Preferably, the method includes:

[0031] Step S001: The aramid fibers are twisted and heated to obtain the aramid fiber bundle to be cleaned;

[0032] Step S002: The aramid fiber bundle to be cleaned is placed in an acetone solution for cleaning, and then dried to obtain the aramid fiber bundle.

[0033] Preferably, step S100 includes:

[0034] Step S110: The aramid fiber bundle is placed in the phosphoric acid solution bath at a temperature of 45-65℃ and a mass concentration of 15-30% for 2-3 hours;

[0035] Step S120: The aramid fiber bundle treated with the phosphoric acid solution is repeatedly washed with distilled water until the washing water is neutral; then the aramid fiber bundle treated with the phosphoric acid solution is washed with acetone.

[0036] Step S130: Drying treatment to obtain the aramid fiber bundles after phosphate roughening modification;

[0037] Step S140: Place the aramid fiber bundles that have been roughened and modified by phosphoric acid in a low-temperature plasma treatment instrument and treat them for 5-10 minutes under the conditions of power of 180-220W, vacuum degree of 20-30Pa and atmosphere flow rate of 25-35ml / min.

[0038] Preferably, step S200 includes:

[0039] Step S210: The graphite oxidation treatment yields the oxidized graphite;

[0040] Step S220: Add the graphite oxide to ethyl acetate and stir to form a first solution;

[0041] Step S230: Mix the coordination titanate coupling agent with ethyl acetate to form a second solution, add the second solution to the first solution, stir and react, and then filter to obtain the modified graphite oxide to be cleaned;

[0042] Step S240: Clean off the ethyl acetate and the coordination titanate coupling agent adhering to the modified graphite oxide to be cleaned, and then dry it to obtain the modified graphite oxide;

[0043] Step S250: Dissolve the modified graphite oxide in deionized water, add hydroiodic acid at room temperature, stir, wash, and dry to obtain the modified reduced graphite oxide.

[0044] Preferably, in step S220, the ethyl acetate is 230-400 parts, and the first solution is obtained by ultrasonic stirring at 40-50KHz and 300-400W for 0.5-0.6h;

[0045] In step S230, the coordination titanate coupling agent is 3-5 parts, the ethyl acetate is 25-50 parts, and the reaction is carried out at 70-75°C and stirred at 450-550 r / min for 2.5-3.5 h to obtain the second solution;

[0046] In step S240, the ethyl acetate is washed with ethanol; the coordination titanate coupling agent is washed with acetone; and the modified graphite oxide is obtained by drying at 100-110°C for 12-13 hours.

[0047] In step S250, the deionized water is 1500-2000 parts, and the modified graphite oxide is dissolved in the deionized water by ultrasonic stirring at 40-50KHz and 400-500W for 0.4-0.6h; the hydroiodic acid is 26-34 parts, the stirring is carried out at 800-1000r / min for 20-28h, the washing is carried out by filtering the obtained product with deionized water until the pH of the filtrate is neutral, and the drying is carried out at 45-55℃ for 6-7h.

[0048] The present invention also provides a method for manufacturing a stylus, the method comprising: cutting a composite material for a stylus as described above to obtain at least a portion of the stylus including a pen tip; or preparing a composite material for a stylus using the method described above, and cutting the composite material for a stylus to obtain at least a portion of the stylus including a pen tip.

[0049] The present invention also provides a stylus, comprising a body and a tip, wherein the tip is connected to the body and is made of a composite material for styluses as described above; or the tip is made of a composite material for styluses prepared by the method described above.

[0050] The beneficial effects of the present invention are: the stylus made from the composite material for styluses provided by the present invention has the advantages of moderate hardness, high wear resistance, and high conductivity.

[0051] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0052] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the drawings:

[0053] Figure 1 Flowchart of the composite material preparation method for styluses.

[0054] Figure 2 This is a flowchart corresponding to one embodiment of preparing aramid fiber bundles.

[0055] Figure 3 for Figure 1 A flowchart corresponding to one embodiment of step S100.

[0056] Figure 4 for Figure 1 A flowchart corresponding to one embodiment of step S200. Detailed Implementation

[0057] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0058] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0059] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0060] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0061] This invention provides a composite material for a stylus, the components of which include plasma-phosphoric acid roughened modified aramid fiber bundles, epoxy resin, modified reduced graphite oxide, soluble polytetrafluoroethylene, curing agent and plasticizer, wherein the mass ratio of the plasma-phosphoric acid roughened modified aramid fiber bundles, the epoxy resin, the soluble polytetrafluoroethylene and the modified reduced graphite oxide is (15-33):(5-14):(0.6-3.5):1.

[0062] Plasma-phosphoric acid roughening modifies aramid fiber bundles by producing a large number of surface active groups, which is beneficial for interfacial adhesion with other components, improves bonding strength, and provides excellent wear resistance.

[0063] Modified reduced graphite oxide enables smooth writing with styluses, exhibits good dispersibility and compatibility, avoids side reactions with resin solutions, and does not affect solution viscosity. Furthermore, modified reduced graphite oxide lowers the graphite percolation threshold while improving the conductivity of the composite material, achieving excellent conductivity with a small dosage. The probability of modified reduced graphite oxide peeling during writing is very low. Moreover, the formation of a conductive network between modified reduced graphite oxide and the plasma-coarsened aramid fiber bundle surface further enhances the composite material's conductivity.

[0064] It is difficult to directly bond plasma-phosphate-modified aramid fiber bundles with modified reduced graphite oxide. However, epoxy resin allows for sufficient contact and bonding between the modified reduced graphite oxide and the plasma-phosphate-modified aramid fiber bundles, resulting in a well-bonded and stable system. Simultaneously, the addition of epoxy resin mitigates the high porosity of single modified aramid fiber materials, improving the hardness and toughness of the stylus tip composite material, making the stylus tip less prone to dispersion and deformation.

[0065] Overall, the composite material for styluses prepared by this invention has moderate hardness, high wear resistance, and high conductivity, solving the problems of poor inter-fiber bonding, easy deformation, and low wear resistance of pure fiber materials.

[0066] As one embodiment, the component ratio of the composite material used for the stylus is:

[0067] The plasma-phosphate roughened modified aramid fiber bundle: 200-250 parts;

[0068] The epoxy resin: 80-100 parts;

[0069] The modified reduced graphite oxide: 8-12 parts;

[0070] The soluble polytetrafluoroethylene: 10-20 parts;

[0071] The curing agent: 30-45 parts;

[0072] The plasticizer: 6-10 parts.

[0073] By using the component ratio of the composite material for the stylus, the resulting composite material for the stylus has moderate hardness, high wear resistance, and high conductivity.

[0074] In a preferred embodiment, the component ratio of the composite material used for the stylus is as follows:

[0075] The plasma-phosphate roughened modified aramid fiber bundle: 225-225 parts;

[0076] The epoxy resin: 90-100 parts;

[0077] The modified reduced graphite oxide: 8-12 parts;

[0078] The soluble polytetrafluoroethylene: 15-20 parts;

[0079] The curing agent: 35-40 parts;

[0080] The plasticizer: 8-10 parts.

[0081] The composite material used in the stylus pen, with its specific component ratio, exhibits excellent hardness, wear resistance, and conductivity.

[0082] As one embodiment, the plasma-phosphoric acid roughening modified aramid fiber bundle is obtained by roughening and modifying the aramid fiber bundle in a phosphoric acid solution, followed by low-temperature plasma treatment.

[0083] As one embodiment, the modified reduced graphite oxide is obtained by sequentially oxidizing and modifying graphite.

[0084] Please see Figure 1 This invention also provides a method for preparing a composite material for a stylus. It can be understood that the method for preparing the composite material for a stylus is the same as the method for preparing the composite material for a stylus mentioned in the foregoing embodiments. The descriptions in the above embodiments of the composite material for a stylus are applicable to the method for preparing the composite material for a stylus in this embodiment.

[0085] The method for preparing composite materials for styluses includes steps S100 to S500.

[0086] In step S100, the aramid fiber bundle is placed in a phosphoric acid solution to obtain a phosphoric acid-modified aramid fiber bundle; the phosphoric acid-modified aramid fiber bundle is then subjected to low-temperature plasma treatment to obtain a plasma-modified phosphoric acid aramid fiber bundle.

[0087] In step S200, graphite is oxidized to obtain graphite oxide, the graphite oxide is modified to obtain modified graphite oxide, and the modified graphite oxide is reduced to obtain modified reduced graphite oxide.

[0088] In step S300, epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide are mixed and stirred to obtain a mixture, wherein the mass ratio of epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide is (5-14):(0.6-3.5):1.

[0089] In step S400, a curing agent and a plasticizer are added to the mixture, and the mixture is stirred to form an adhesive.

[0090] In step S500, the plasma-phosphoric acid roughened modified aramid fiber bundle is immersed in the adhesive solution, and the immersed plasma-phosphoric acid roughened modified aramid fiber bundle is cured and foamed to obtain a composite material for stylus pen; wherein, the mass ratio of the plasma-phosphoric acid roughened modified aramid fiber bundle to the modified reduced graphite oxide is (15-33):1.

[0091] Aramid fibers possess high wear resistance and rubber-like high elastic recovery and high elongation at break. However, due to their unique structure of high crystallinity and high orientation, aramid fibers have a smooth surface and few chemically active sites, resulting in poor surface bonding performance. In the method provided in this invention, surface modification with a phosphoric acid solution roughens the aramid fiber surface and increases the content of surface-active groups CO / CN, thereby improving the surface bonding strength between the fiber and materials such as resins and graphite. Further low-temperature plasma treatment of the aramid fiber increases the content of active groups such as -C=O and OC=O. The increase in surface-active groups and surface roughening enhance the interfacial adhesion between the aramid fiber and other components, further improving its bonding strength. Simultaneously, the modified aramid fiber exhibits better wear resistance.

[0092] Ordinary graphite exhibits good conductivity, corrosion resistance, and lubricity at room temperature. Its lubricity makes stylus writing smoother. However, ordinary graphite has poor dispersibility and compatibility in composite materials such as resins, easily leading to agglomeration or peeling. Furthermore, if added in large quantities to composite materials, it can easily peel off during writing, potentially leaving black marks on large screens and affecting the writing experience. The method provided in this invention, through oxidation-modification-reduction treatment of graphite, achieves better dispersibility and compatibility in composite materials. It also lowers the graphite permeation threshold while improving the conductivity of the composite material, achieving better conductivity than ordinary graphite in composite materials with a smaller amount. Furthermore, the less graphite permeates, the lower the probability of graphite peeling during writing. Specifically, oxidation treatment increases the content of active functional groups (hydroxyl, carboxyl, epoxy groups) in graphite, which is beneficial for the modification of oxidized graphite. Modification treatment improves the dispersibility and compatibility of graphite in composite materials and avoids side reactions with resin solutions, without affecting the solution viscosity. The modified graphite oxide was reduced to restore its electrical conductivity while preserving its good compatibility with the resin. The modified reduced graphite oxide and the plasma-phosphate-coarsened modified aramid fiber bundles formed a conductive network, giving the composite material excellent conductivity and improving the writing smoothness of the pen tip.

[0093] It is difficult to directly bond plasma-phosphate-modified aramid fiber bundles with modified reduced graphite oxide. However, epoxy resin allows for sufficient contact and bonding between the modified reduced graphite oxide and the plasma-phosphate-modified aramid fiber bundles, resulting in a well-bonded and stable system. Simultaneously, the addition of epoxy resin mitigates the high porosity of single modified aramid fiber materials, improving the hardness and toughness of the stylus tip composite material, making the stylus tip less prone to dispersion and deformation.

[0094] The composite material for styluses prepared by this invention has moderate hardness, high wear resistance, and high conductivity, solving the problems of poor inter-fiber bonding, easy deformation, and low wear resistance of pure fiber materials.

[0095] In the method described, when the mass ratio of epoxy resin, soluble polytetrafluoroethylene, plasma-phosphoric acid roughened modified aramid fiber bundle, and modified reduced graphene oxide is (5-14):(0.6-3.5):(15-33):1, the composite material for the stylus obtained is of moderate hardness, high wear resistance, and good conductivity.

[0096] It is understandable that there is no restriction on the order in which steps S100 and S200 are executed. S100 can be executed first, followed by step S200; or S200 can be executed first, followed by step S100; or steps S100 and S200 can be executed simultaneously.

[0097] In one embodiment, in step 300, the epoxy resin is first dissolved in ethyl acetate, and then the soluble polytetrafluoroethylene and the modified reduced graphene oxide are added. Ethyl acetate, as a solvent, promotes dispersibility, facilitating thorough mixing of the epoxy resin, soluble polytetrafluoroethylene, and modified reduced graphene oxide. After mixing, the ethyl acetate can be removed by baking or other operations. In another embodiment, before step S500, the mixture is placed in an oven and baked to remove the ethyl acetate.

[0098] In some embodiments, ethyl acetate, which serves as the solvent for the epoxy resin, can be replaced with other solvents, or the epoxy resin, soluble polytetrafluoroethylene, and modified reduced graphene oxide can be fully mixed through process control without adding a solvent.

[0099] As one embodiment, the allocation ratio of each group in the method provided by the present invention is as follows:

[0100] Plasma-phosphoric acid roughening modified aramid fiber bundles: 200-250 parts;

[0101] Epoxy resin: 80-100 parts;

[0102] Ethyl acetate: 60-150 parts;

[0103] Modified reduced graphite oxide: 8-12 parts;

[0104] Soluble polytetrafluoroethylene: 10-20 parts;

[0105] Hardener: 30-45 parts;

[0106] Plasticizer: 6-10 parts.

[0107] As one example, epoxy resins include, but are not limited to, LY1564 type epoxy resin and bisphenol A type epoxy resin with good flowability.

[0108] As one example, the curing agent includes, but is not limited to, XB3487 epoxy resin curing agent and amine curing agents that are compatible with epoxy resin.

[0109] As one example, the plasticizer includes, but is not limited to, phenyl glycidyl ether, top-grade glycidyl ether, allyl glycidyl ether, etc.

[0110] Please see Figure 2 As one embodiment, the method provided by the present invention includes steps S001 and S002. The aramid fiber bundles obtained in step S100 are prepared through steps S001 and S002.

[0111] In step S001, the aramid fibers are twisted and heated to obtain a bundle of aramid fibers to be cleaned.

[0112] As one embodiment, aramid fibers are sequentially stranded and then heat-set at 280-320°C to obtain aramid fiber bundles. Preferably, the aramid fiber bundles are obtained by heat-setting at 290-310°C, and more preferably at 300°C.

[0113] As one example, aramid fibers can be twisted and heat-set to form rod-like shapes for use in stylus manufacturing. It is understood that the shape of the aramid fiber bundles is not limited and can be processed into other desired shapes.

[0114] In step S002, the aramid fiber bundle to be cleaned is placed in an acetone solution for cleaning and then dried to obtain the aramid fiber bundle.

[0115] As one embodiment, the aramid fiber bundle is placed in an ultrasonic cleaner containing acetone solution for 2-3 hours, and then dried at a temperature of 90-100°C for 2-3 hours. Preferably, the cleaning time is 2.5 hours and the temperature is 95°C.

[0116] In step S100, the aramid fiber bundle is placed in a phosphoric acid solution to obtain a phosphoric acid-modified aramid fiber bundle; the phosphoric acid-modified aramid fiber bundle is then subjected to low-temperature plasma treatment to obtain a plasma-modified phosphoric acid aramid fiber bundle.

[0117] Please see Figure 3 As one embodiment, step S100 includes steps S110 to S140.

[0118] In step S110, the aramid fiber bundle is placed in a phosphoric acid solution bath at a temperature of 45-65°C and a mass concentration of 15-30% for 2-3 hours.

[0119] In step S120, the aramid fiber bundle treated with the phosphoric acid solution is repeatedly washed with distilled water until the washing water is neutral; then the aramid fiber bundle treated with the phosphoric acid solution is washed with acetone.

[0120] In step S130, the drying process yields the aramid fiber bundles after phosphate roughening modification.

[0121] In step S140, the aramid fiber bundles roughened and modified with phosphoric acid are placed in a low-temperature plasma treatment instrument and treated for 5-10 minutes under the conditions of power of 180-220W, vacuum degree of 20-30Pa, and atmosphere flow rate of 25-35ml / min.

[0122] In one specific embodiment, in step S110, the temperature can be selected as 50-55°C, preferably 55°C. The mass concentration of the phosphoric acid solution is preferably 20-25%.

[0123] As a specific embodiment, in step S130, the aramid fiber bundles cleaned with acetone are dried for 3-5 hours under a negative pressure of 3-5 kPa and a temperature of 80-100°C.

[0124] It is understandable that processing in a low-temperature plasma treatment instrument with a power of 180-220W, a vacuum degree of 20-30Pa, and an atmosphere flow rate of 25-35ml / min for 5-10 minutes can better increase the content of active groups.

[0125] In step S200, graphite is oxidized to obtain graphite oxide, the graphite oxide is modified to obtain modified graphite oxide, and the modified graphite oxide is reduced to obtain modified reduced graphite oxide.

[0126] Please see Figure 4 As one embodiment, step S200 specifically includes steps S210 to S250.

[0127] In step S210, the graphite oxidation treatment yields the graphite oxide.

[0128] In step S220, the graphite oxide is added to ethyl acetate and stirred to form a first solution.

[0129] In step S230, the coordination titanate coupling agent is uniformly mixed with ethyl acetate to form a second solution. The second solution is added to the first solution, and after stirring and reacting, the modified graphite oxide to be cleaned is obtained.

[0130] In step S240, the ethyl acetate and the coordination titanate coupling agent adhering to the modified graphite oxide to be cleaned are washed away, and then dried to obtain the modified graphite oxide.

[0131] In step S250, the modified graphite oxide is dissolved in deionized water, hydroiodic acid is added at room temperature, and then the mixture is stirred, washed, and dried to obtain the modified reduced graphite oxide.

[0132] It is understandable that the coupling agent used in the modification treatment is not limited, but a coordination titanate coupling agent is preferred, as it can better avoid side reactions between the modified reduced graphite oxide and the epoxy resin. In the reduction treatment, the reducing agent is not limited, but hydroiodic acid is preferred, as it can avoid damaging the graphite structure, and the generated iodine, due to its stronger electronegativity than graphite, will adsorb onto the graphite surface, exchanging charge with the graphite matrix and thus enhancing conductivity.

[0133] It is understood that the specific method of graphite oxidation treatment is not limited. As a preferred embodiment, step S210 includes steps S210a to S210h, which are performed sequentially.

[0134] In step S210a, 200-350 portions of concentrated sulfuric acid with a mass concentration of 95-97% are placed in an ice-water bath at 0-5℃ and cooled for 5-6 minutes.

[0135] In step S210b, 6-8 parts of graphite powder with a particle size of 11-20 μm are added to concentrated sulfuric acid and stirred at a speed of 100-150 r / min for 30-35 min.

[0136] In step S210c, add 10-18 parts of sodium nitrate and continue stirring the mixture at 100-150 r / min for 30-35 min.

[0137] In step S210d, 10-18 parts of potassium permanganate are slowly added over 0.5-1h, and the mixture is reacted in a water bath at 5-25℃ for 2-3h.

[0138] In step S210e, 380-600 parts of deionized water are slowly added over 0.5-1h, followed by stirring for 15-18min at a speed of 200-300r / min.

[0139] In step S210f, 130-220 parts of 3% hydrogen peroxide solution are added until the solution turns bright yellow.

[0140] In step S210g, the bright yellow solution is filtered, and the product is washed with 5% dilute hydrochloric acid.

[0141] In step S210h, the product is washed with deionized water until the pH of the filtrate is close to neutral and sulfate ions cannot be detected by barium chloride solution; the product is then vacuum dried at 60-65℃ for 12-13h to obtain graphite oxide.

[0142] As an example, in step S220, the ethyl acetate is 230-400 parts, and the first solution is obtained by ultrasonic stirring at 40-50KHz and 300-400W for 0.5-0.6h.

[0143] As an example, in step S230, the coordination titanate coupling agent is 3-5 parts, the ethyl acetate is 25-50 parts, and the reaction is carried out at 70-75°C and stirred at 450-550 r / min for 2.5-3.5 h to obtain the second solution.

[0144] As an example, in step S240, the ethyl acetate is washed with ethanol; the coordination titanate coupling agent is washed with acetone; and the modified graphite oxide is obtained by drying at a temperature of 100-110°C for 12-13 hours.

[0145] As one embodiment, in step S250, the deionized water is 1500-2000 parts, and the modified graphite oxide is dissolved in the deionized water by ultrasonic stirring at 40-50KHz and 400-500W for 0.4-0.6h; the hydroiodic acid is 26-34 parts; the stirring (e.g., magnetic stirring) is carried out at a speed of 800-1000r / min for 20-28h (specifically, it can be 24h); the washing is carried out by filtering the obtained product with deionized water until the pH of the filtrate is neutral; and the drying is carried out at a temperature of 45-55℃ for 6-7h.

[0146] It is understandable that oxidation treatment with oxidizing inorganic acids (phosphoric acid) can increase the content of active functional groups (hydroxyl, carboxyl, epoxy groups) in graphite, which is beneficial for coupling agent modification. Coordination-type titanate coupling agent modification improves the dispersibility and compatibility of graphite in composite materials, and better avoids side reactions with the resin solution without affecting the solution viscosity. Reduction of the modified graphite oxide with hydroiodic acid restores its electrical conductivity while preserving the good compatibility between the modified graphite and the resin.

[0147] As one embodiment, in step S500, the plasma-phosphoric acid roughened modified aramid fiber bundle is immersed in the adhesive solution for 15-20 minutes; the curing and foaming is carried out at a temperature of 70-80°C for 6-8 hours.

[0148] As one example, epoxy resin is dissolved in ethyl acetate solvent, then soluble polytetrafluoroethylene is added, and modified reduced graphene oxide is added while stirring. The mixture is then ultrasonically stirred for 1.5-2 hours at 40-50 kHz and 300-400 W.

[0149] As one example, a mixture of epoxy resin dissolved in ethyl acetate solvent, soluble polytetrafluoroethylene, and modified reduced graphene oxide is placed in an oven at 60-80°C for 6-10 hours to remove ethyl acetate.

[0150] In step S400, the mixture is stirred at 450-550 r / min for 15-20 min to remove air bubbles and obtain a glue solution, which can be injected into an impregnation tank. The plasma-phosphoric acid roughened modified aramid fiber bundles can be immersed in the impregnation tank containing the glue solution.

[0151] The present invention also provides a composite material for a stylus, wherein the composite material for a stylus is prepared by the method for preparing a composite material for a stylus as described above.

[0152] The present invention also provides a method for manufacturing a stylus, the method comprising preparing a composite material for a stylus using the method described above, and cutting the composite material for a stylus to obtain at least a portion of the stylus, including the pen tip.

[0153] The present invention also provides a stylus, comprising a body and a tip, wherein the tip is connected to the body and is made of a composite material for styluses as described above.

[0154] It is understood that the stylus may be made entirely of the composite material used for styluses, or only the tip may be made of the composite material used for styluses.

[0155] The following describes the preparation of composite materials for styluses using experimental and control groups, and the performance of styluses made from these composite materials was tested to verify the technical effects of this application. The styluses in the experimental group were prepared using the method provided in this application, while the styluses in the control group were not prepared using this method. The methods (including various experimental conditions) for preparing plasma-phosphoric acid roughened surface-modified aramid fiber bundles from aramid fiber bundles were identical in both the experimental and control groups, and the methods for preparing modified reduced graphene oxide were also completely consistent.

[0156] Experimental group 1:

[0157] Step T1: The aramid fibers are sequentially ply-plyed and heated to 280°C to obtain 200 bundles of aramid fibers to be cleaned; the bundles of aramid fibers to be cleaned are placed in an ultrasonic cleaner containing acetone solution for 2 hours and then dried at 90°C for 2 hours to obtain the aramid fiber bundles.

[0158] Step T2: Prepare 200 parts of plasma-phosphoric acid roughened surface modified aramid fiber bundles and 8 parts of modified reduced graphite oxide.

[0159] Step T3: Dissolve 80 parts of LY1564 epoxy resin in 60 parts of ethyl acetate solvent, then add 10 parts of soluble polytetrafluoroethylene, and while stirring, add 8 parts of modified reduced graphene oxide. Then, ultrasonically stir at 40KHz and 300W for 1.5h to obtain a mixture.

[0160] Step T4: Place the mixture in a 60°C oven for 10 hours to remove the ethyl acetate solvent.

[0161] Step T5: Add 30 parts of curing agent and 6 parts of epoxy resin plasticizer, stir at 450 r / min for 15 min to remove air bubbles and obtain adhesive solution, then inject the adhesive solution into the impregnation tank.

[0162] Step T6: Immerse the plasma-phosphate roughened modified aramid fiber bundle in a glue bath containing adhesive solution for 15 minutes, and then cure and foam the glued fiber at 70°C for 8 hours to obtain the composite material for stylus pen.

[0163] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0164] Experimental group 2:

[0165] Step T1: Aramid fibers were sequentially plyed and heated to 300°C to obtain 230 bundles of aramid fibers to be cleaned. The bundles of aramid fibers to be cleaned were placed in an ultrasonic cleaner containing acetone solution for 2.5 hours and then dried at 95°C for 2 hours to obtain the aramid fiber bundles.

[0166] Step T2: Prepare 230 parts of plasma-phosphoric acid roughened surface modified aramid fiber bundles and 10 parts of modified reduced graphite oxide.

[0167] Step T3: Dissolve 95 parts of LY1564 epoxy resin in 100 parts of ethyl acetate solvent, then add 15 parts of soluble polytetrafluoroethylene, and while stirring, add 10 parts of modified reduced graphene oxide. Then, ultrasonically stir at 45KHz and 350W for 1.7h to obtain a mixture.

[0168] Step T4: The mixture was then placed in a 70°C oven for 8.5 h to remove the ethyl acetate solvent.

[0169] Step T5: Add 37 parts curing agent and 8 parts epoxy resin plasticizer, stir at 500 r / min for 18 min to remove air bubbles and obtain adhesive solution, then inject the adhesive solution into the impregnation tank.

[0170] Step T6: Immerse the plasma-phosphate roughened modified aramid fiber bundle in a glue bath containing adhesive solution for 18 minutes, and then cure and foam the glued fiber at 70°C for 7.2 hours to obtain the composite material for stylus pen.

[0171] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0172] Experimental group 3:

[0173] Step T1: Aramid fibers are sequentially ply-plyed and heated to set at 320℃ to obtain 250 bundles of aramid fibers to be cleaned. The bundles of aramid fibers to be cleaned are placed in an ultrasonic cleaner containing acetone solution and cleaned for 3 hours, and then dried at 100℃ for 2 hours to obtain aramid fiber bundles.

[0174] Step T2: Prepare 250 parts of plasma-phosphoric acid roughened surface modified aramid fiber bundles and 12 parts of modified reduced graphite oxide.

[0175] Step T3: Dissolve 100 parts of LY1564 epoxy resin in 150 parts of ethyl acetate solvent, then add 20 parts of soluble polytetrafluoroethylene, and while stirring, add 12 parts of modified reduced graphene oxide. Then, ultrasonically stir at 50KHz and 400W for 2 hours to obtain a mixture.

[0176] Step T4: Place the mixture in an 80°C oven for 6 hours to remove the ethyl acetate solvent.

[0177] Step T5: Add 45 parts of curing agent and 10 parts of epoxy resin plasticizer, stir at 550 r / min for 20 min to remove air bubbles and obtain adhesive solution, then inject the adhesive solution into the impregnation tank.

[0178] Step T6: Immerse the plasma-phosphate roughened modified aramid fiber bundle in a glue bath containing adhesive solution for 20 minutes, and then cure and foam the glued fiber at 80°C for 6 hours to obtain the composite material for stylus pen.

[0179] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0180] Comparison Group 1: (The only difference from experimental group 2 is the unmodified aramid fiber.)

[0181] Step T1: The aramid fibers are sequentially ply-plyed and heated to 300°C to obtain 230 bundles of aramid fibers to be cleaned. The bundles of aramid fibers to be cleaned are placed in an ultrasonic cleaner containing acetone solution and cleaned for 2.5 hours. Then they are dried at 95°C for 2 hours to obtain the aramid fiber bundles.

[0182] Step T2: Prepare 10 portions of modified reduced graphite oxide.

[0183] Step T3: Dissolve 95 parts of LY1564 epoxy resin in 100 parts of ethyl acetate solvent, then add 15 parts of soluble polytetrafluoroethylene, and while stirring, add 10 parts of modified reduced graphene oxide. Then, ultrasonically stir at 45KHz and 350W for 1.7h to obtain a mixture.

[0184] Step T4: Place the mixture in a 70°C oven for 8.5 hours to remove the ethyl acetate solvent.

[0185] Step T5: Add 37 parts of curing agent and 8 parts of epoxy resin plasticizer, stir at 500 r / min for 18 min to remove the adhesive solution, and pour the adhesive solution into the impregnation tank.

[0186] Step T6: Immerse the aramid fiber bundle in a glue bath containing adhesive solution for 18 minutes, and then cure and foam the glue-impregnated fibers at 70°C for 7.2 hours to obtain the composite material for styluses.

[0187] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0188] Comparison Group 2: (The only difference from experimental group 2 is the type of resin added.)

[0189] Step T1: Aramid fibers were sequentially plyed and heated to 300°C to obtain 230 bundles of aramid fibers to be cleaned. The bundles of aramid fibers to be cleaned were placed in an ultrasonic cleaner containing acetone solution for 2.5 hours and then dried at 95°C for 2 hours to obtain aramid fiber bundles.

[0190] Step T2: Prepare 230 parts of plasma-phosphoric acid roughened surface modified aramid fiber bundles and 10 parts of modified reduced graphite oxide.

[0191] Step T3: Dissolve 95 parts of type 2123 phenolic resin in 100 parts of anhydrous ethanol solvent, then add 15 parts of soluble polytetrafluoroethylene, and while stirring, add 10 parts of modified reduced graphene oxide. Then, ultrasonically stir at 45KHz and 350W for 1.7h to obtain a mixture.

[0192] Step T4: Place the mixture in a 70°C oven for 8.5 h to remove the ethyl acetate solvent.

[0193] Step T5: Add 37 parts curing agent and 8 parts epoxy resin plasticizer, stir at 500 r / min for 18 min to remove air bubbles and obtain adhesive solution, then inject the adhesive solution into the impregnation tank.

[0194] Step T6: Immerse the plasma-phosphate roughened modified aramid fiber bundle in a glue bath containing adhesive solution for 18 minutes, and then cure and foam the glued fiber at 70°C for 7.2 hours to obtain the composite material for stylus pen.

[0195] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0196] Comparison Group 3: (The only difference from Experimental Group 2 is that the graphite was not subjected to oxidation-modification-reduction treatment.)

[0197] Step T1: Aramid fibers are sequentially plyed and heated to 300°C to obtain 230 bundles of aramid fibers to be cleaned. The bundles of aramid fibers to be cleaned are placed in an ultrasonic cleaner containing acetone solution and cleaned for 2.5 hours. Then, they are dried at 95°C for 2 hours to obtain aramid fiber bundles.

[0198] Step T2: Prepare 230 plasma-phosphoric acid roughened surface modified aramid fiber bundles.

[0199] Step T3: Dissolve 95 parts of LY1564 epoxy resin in 100 parts of ethyl acetate solvent, then add 15 parts of soluble polytetrafluoroethylene, and while stirring, add 10 parts of ordinary graphite. Then, ultrasonically stir at 45KHz and 350W for 1.7h to obtain a mixture.

[0200] Step T4: Place the mixture in a 70°C oven for 8.5 h to remove the ethyl acetate solvent.

[0201] Step T5: Add 37 parts of curing agent and 8 parts of epoxy resin plasticizer, stir at 500 r / min for 18 min to remove air bubbles and obtain adhesive solution, then inject the adhesive solution into the impregnation tank.

[0202] Step T6: Immerse the plasma-phosphate roughened modified aramid fiber bundle in a glue bath containing adhesive solution for 18 minutes, and then cure and foam the glued fiber at 70°C for 7.2 hours to obtain the composite material for stylus pen.

[0203] Step T7: Cut the fully foamed composite material for the stylus into the required length, and finally grind it to obtain the stylus.

[0204] The styluses prepared in experimental groups 1-3 and control groups 1-3 were tested according to the following testing methods:

[0205]

[0206] The measured data are as follows:

[0207]

[0208] As can be seen from the measured data above, the stylus prepared according to the method provided by the present invention has the advantages of moderate hardness (a hardness of 60-75A is what users prefer, and more preferably, a hardness of 65-70A), low resistance, and low frictional loss.

[0209] It should be noted that the use of step numbers (letters or numbers) to refer to certain specific method steps in this invention is merely for the purpose of convenience and brevity in description, and is by no means intended to restrict the order of these method steps. Those skilled in the art will understand that the order of the relevant method steps should be determined by the technology itself and should not be unduly restricted by the existence of step numbers. Those skilled in the art can determine various permissible and reasonable orderings of steps based on the technology itself.

[0210] Those skilled in the art will understand that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0211] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A composite material for a stylus, characterized in that, The composite material used for the stylus includes plasma-phosphoric acid roughened modified aramid fiber bundles, epoxy resin, modified reduced graphite oxide, soluble polytetrafluoroethylene, curing agent and plasticizer. The mass ratio of the plasma-phosphoric acid roughened modified aramid fiber bundle, the epoxy resin, the soluble polytetrafluoroethylene and the modified reduced graphene oxide is (15-33):(5-14):(0.6-3.5):

1.

2. The composite material for a stylus as described in claim 1, characterized in that, The composition ratio of the composite material used for the stylus is as follows: The plasma-phosphate roughened modified aramid fiber bundle: 200-250 parts; The epoxy resin: 80-100 parts; The modified reduced graphite oxide: 8-12 parts; The soluble polytetrafluoroethylene: 10-20 parts; The curing agent: 30-45 parts; The plasticizer: 6-10 parts.

3. A method for preparing a composite material for a stylus, characterized in that, include: Step S100: Place the aramid fiber bundle in a phosphoric acid solution to obtain the aramid fiber bundle after phosphoric acid roughening modification; The aramid fiber bundles modified by phosphoric acid roughening were subjected to low-temperature plasma treatment to obtain plasma-phosphoric acid roughening modified aramid fiber bundles. Step S200: Graphite oxidation treatment yields graphite oxide, the graphite oxide is modified to obtain modified graphite oxide, and the modified graphite oxide is reduced to obtain modified reduced graphite oxide. Step S300: Mix epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide, and stir to obtain a mixture; wherein the mass ratio of epoxy resin, soluble polytetrafluoroethylene and the modified reduced graphene oxide is (5-14):(0.6-3.5):1; Step S400: Add curing agent and plasticizer to the mixture and stir to form an adhesive solution; Step S500: Immerse the plasma-phosphate roughened modified aramid fiber bundle in the adhesive solution, and cure and foam the impregnated plasma-phosphate roughened modified aramid fiber bundle to obtain a composite material for stylus pen; wherein, the mass ratio of the plasma-phosphate roughened modified aramid fiber bundle to the modified reduced graphite oxide is (15-33):

1.

4. The method for preparing the composite material for a stylus as described in claim 3, characterized in that, The allocation ratios for each group in the method are as follows: The plasma-phosphate roughened modified aramid fiber bundle: 200-250 parts; The epoxy resin: 80-100 parts; The modified reduced graphite oxide: 8-12 parts; The soluble polytetrafluoroethylene: 10-20 parts; The curing agent: 30-45 parts; The plasticizer: 6-10 parts.

5. The method for preparing the composite material for a stylus as described in claim 4, characterized in that, In step 300, the epoxy resin is first dissolved in ethyl acetate, and then the soluble polytetrafluoroethylene and the modified reduced graphene oxide are added. Before step S500, the mixture is placed in an oven and baked to remove the ethyl acetate; The ethyl acetate is in the form of 60-150 parts.

6. The method for preparing the composite material for a stylus as described in claim 3, characterized in that, The method includes: Step S001: The aramid fibers are twisted and heated to obtain the aramid fiber bundle to be cleaned; Step S002: The aramid fiber bundle to be cleaned is placed in an acetone solution for cleaning, and then dried to obtain the aramid fiber bundle.

7. The method for preparing the composite material for a stylus as described in claim 3, characterized in that, Step S100 includes: Step S110: The aramid fiber bundle is placed in the phosphoric acid solution bath at a temperature of 45-65℃ and a mass concentration of 15-30% for 2-3 hours; Step S120: The aramid fiber bundle treated with the phosphoric acid solution is repeatedly washed with distilled water until the washing water is neutral; then the aramid fiber bundle treated with the phosphoric acid solution is washed with acetone. Step S130: Drying treatment to obtain the aramid fiber bundles after phosphate roughening modification; Step S140: Place the aramid fiber bundles that have been roughened and modified by phosphoric acid in a low-temperature plasma treatment instrument and treat them for 5-10 minutes under the conditions of power of 180-220W, vacuum degree of 20-30Pa and atmosphere flow rate of 25-35ml / min.

8. The method for preparing the composite material for a stylus as described in claim 4, characterized in that, Step S200 includes: Step S210: The graphite oxidation treatment yields the oxidized graphite; Step S220: Add the graphite oxide to ethyl acetate and stir to form a first solution; Step S230: Mix the coordination titanate coupling agent with ethyl acetate to form a second solution, add the second solution to the first solution, stir and react, and then filter to obtain the modified graphite oxide to be cleaned; Step S240: Clean off the ethyl acetate and the coordination titanate coupling agent adhering to the modified graphite oxide to be cleaned, and then dry it to obtain the modified graphite oxide; Step S250: Dissolve the modified graphite oxide in deionized water, add hydroiodic acid at room temperature, stir, wash, and dry to obtain the modified reduced graphite oxide.

9. The method for preparing the composite material for a stylus as described in claim 8, characterized in that, In step S220, the ethyl acetate is 230-400 parts, and the solution is obtained by ultrasonic stirring at 40-50KHz and 300-400W for 0.5-0.6h; In step S230, the coordination titanate coupling agent is 3-5 parts, the ethyl acetate is 25-50 parts, and the reaction is carried out at 70-75°C and stirred at 450-550 r / min for 2.5-3.5 h to obtain the second solution; In step S240, the ethyl acetate is washed with ethanol; the coordination titanate coupling agent is washed with acetone; and the modified graphite oxide is obtained by drying at 100-110°C for 12-13 hours. In step S250, the deionized water is 1500-2000 parts, and the modified graphite oxide is dissolved in the deionized water by ultrasonic stirring at 40-50KHz and 400-500W for 0.4-0.6h; the hydroiodic acid is 26-34 parts, the stirring is carried out at 800-1000r / min for 20-28h, the washing is carried out by filtering the obtained product with deionized water until the pH of the filtrate is neutral, and the drying is carried out at 45-55℃ for 6-7h.

10. A method for manufacturing a stylus, characterized in that, The method includes: cutting a composite material for a stylus as described in any one of claims 1-2 to obtain a stylus including at least a portion of a pen tip; or preparing a composite material for a stylus using the method described in any one of claims 3-9, and cutting the composite material for a stylus to obtain a stylus including at least a portion of a pen tip.

11. A stylus, comprising a body and a tip, wherein the tip is connected to the body, characterized in that, The pen tip is made of a composite material for a stylus as described in any one of claims 1-2; or the pen tip is made of a composite material for a stylus prepared by the method described in any one of claims 3-9.

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