Environment-friendly carbon fiber treating agent, preparation method and application thereof

Abstract

This invention belongs to the technical field of carbon fiber treatment agents, specifically relating to an environmentally friendly carbon fiber treatment agent, its preparation method, and its application. The environmentally friendly carbon fiber treatment agent, by weight percentage, comprises the following components: 6-10% polyol, 0.1-0.3% furan-cyclic diol, 0.5-1.5% isocyanate, 20-30% solvent A, 0.2-0.7% catalyst, 0.2-1% phenoxy resin, 0.1-0.4% carboxylic acid-siloxane copolymer containing maleimide groups, with solvent B added to make the balance to 100%. The environmentally friendly carbon fiber treatment agent provided by this invention enables the carbon fiber and polyamide resin to form good interfacial wetting and stress transfer effects, thereby effectively improving the mechanical properties of the carbon fiber sheet.

Description

Technical Field

[0001] This invention belongs to the field of carbon fiber treatment agent technology, specifically relating to an environmentally friendly carbon fiber treatment agent, its preparation method, and its application. Background Technology

[0002] Carbon fiber, due to its lightweight, high strength, high rigidity and excellent rebound properties, has broad application prospects in high-performance sports shoes (especially racing shoes and basketball shoes). It is usually processed into carbon fiber plates and placed in the sole to provide strong propulsion and energy return.

[0003] Traditional carbon fiber sheets are usually made by impregnating carbon fibers with thermosetting resin (epoxy resin) and then curing them. However, these carbon fiber sheets have the disadvantages of being too rigid and stiff, and having poor cushioning and joint protection for the ankle area.

[0004] Currently, the use of thermoplastic resins (polyamide resins) to modify carbon fibers to prepare carbon fiber sheets with both flexural stiffness and structural strength is a research hotspot. However, polyamide resins exhibit significant non-polar or weakly polar characteristics due to the large number of methylene groups in their molecular chains, and carbon fibers, with their relatively smooth surface and lack of active functional groups, are inert. This results in poor interfacial compatibility between the two, which reduces the mechanical properties of the carbon fiber sheets and affects their performance in use.

[0005] Chinese Patent CN 119192828 B discloses a polyamide resin composition and its preparation method. This polyamide resin composition includes: long-chain polyamide resin, MXD6 polyamide resin, long-chain polyamide thermoplastic elastomer, high molecular weight maleic anhydride-functionalized liquid polybutadiene, plasma-treated carbon fibers, and optional additives. This technical solution uses plasma gas to activate the carbon fiber surface, resulting in etching and the acquisition of carboxyl, carbonyl, and hydroxyl active groups on the plasma-treated surface. However, the plasma treatment equipment has high energy consumption and high cost.

[0006] Chinese Patent No. CN 122587469 A discloses a lightweight, highly elastic long-chain nylon carbon sheet material and its preparation method. The material consists of 5-10% toughening agent, 10-20% carbon fiber, 5-10% compatibilizer, 3-8% nylon microfoam masterbatch, 0.5-3% carbon fiber surface treatment agent, 0.2-1% antioxidant, 0.2-0.7% lubricant, 1-3% colorant, and the balance being PA612 medium-viscosity resin. This technical solution uses commercially available carbon fiber surface treatment agent; however, a compatibilizer is required to improve the compatibility between the weakly polar long-chain nylon and the carbon fiber.

[0007] In addition, due to the relatively smooth surface of carbon fiber and the lack of active functional groups, it is inert and has poor bonding strength with the sole substrate, making it prone to delamination or slippage, which affects the safety and performance of high-performance sports shoes. The above-mentioned existing technologies have not addressed this technical problem. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide an environmentally friendly carbon fiber treatment agent, its preparation method, and its application.

[0009] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an environmentally friendly carbon fiber treatment agent, comprising, by weight percentage: 6-10% polyol, 0.1-0.3% furan-cyclodiol, 0.5-1.5% isocyanate, 20-30% solvent A, 0.2-0.7% catalyst, 0.2-1% phenoxy resin, 0.1-0.4% carboxylic acid-siloxane copolymer containing maleimide groups, with solvent B supplemented to make up to 100%.

[0010] Preferably, the polyol is a polyester polyol based on adipic acid and 1,6-hexanediol, with a number average molecular weight of 3000-3500 and a hydroxyl value of 30-40 mgKOH / g.

[0011] Preferably, the furan-containing diol is selected from at least one of 2,5-furandiethanol and 2,5-furandipropanol.

[0012] Preferably, the isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, terephthalic diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, phenylmethylene diisocyanate, and dimethylbiphenyl diisocyanate.

[0013] Preferably, solvent A is dimethyl carbonate.

[0014] Preferably, the catalyst is selected from at least one of dibutyltin dilaurate and stannous octoate.

[0015] Preferably, the weight-average molecular weight of the phenoxy resin is 25,000-35,000.

[0016] Preferably, the preparation method of the carboxylic acid-siloxane copolymer containing maleimide group is as follows: mix carboxylic acid containing maleimide group and N,N-dimethylformamide, add 1,3-bis(3-glycidyl ether oxypropyl)tetramethyldisiloxane and tetrabutylammonium bromide, heat and stir to react, and after the reaction is completed, perform vacuum treatment to obtain the copolymer.

[0017] Through the above technical solution, a carboxylic acid-siloxane copolymer containing a maleimide group is prepared by ring-opening reaction of a carboxylic acid containing a maleimide group and 1,3-bis(3-glycidyl ether propyl)tetramethyldisiloxane.

[0018] Preferably, the carboxylic acid containing the maleimide group is selected from at least one of 5-maleimide valerate, 6-maleimide hexanoic acid, and 11-maleamido undecanoic acid.

[0019] Preferably, the molar ratio of the carboxylic acid containing the maleimide group and 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane is 1:0.45-0.55.

[0020] Preferably, the mass ratio of the carboxylic acid containing the maleimide group to N,N-dimethylformamide is 1:2-5.

[0021] Preferably, the amount of tetrabutylammonium bromide added is 0.5-3% of the total weight of the carboxylic acid containing maleimide group and 1,3-bis(3-glycidyl ether oxypropyl)tetramethyldisiloxane.

[0022] Preferably, the temperature of the heating and stirring reaction is 80-90℃, and the reaction time is 5-8h.

[0023] Preferably, solvent B is butanone, acetone and N-ethyl-2-pyrrolidone in a weight ratio of 3-4:2-3:0.3-0.6.

[0024] Secondly, the present invention provides a method for preparing an environmentally friendly carbon fiber treatment agent, comprising the following steps: (1) Add polyol, isocyanate and solvent A to the reaction vessel, heat and stir to dissolve to obtain mixture A; (2) Heat mixture A, add catalyst under nitrogen protection, and stir to obtain mixture B; (3) First add furan ring diol and continue stirring, then add phenoxy resin and carboxylic acid-siloxane copolymer containing maleimide group, and continue stirring to obtain mixture C; (4) Add solvent B and continue stirring to obtain an environmentally friendly carbon fiber treatment agent.

[0025] Through the above technical solution, a polyurethane prepolymer is first prepared. A furan ring-containing diol is used to extend the polyurethane prepolymer chain, introducing furan rings into the polyurethane prepolymer molecular chain. The hydroxyl groups in the phenoxy resin and the carboxylic acid-siloxane copolymer containing maleimide groups can further react with the remaining -NCO in the polyurethane prepolymer containing furan rings to obtain an environmentally friendly carbon fiber treatment agent.

[0026] Thirdly, this invention provides an application of an environmentally friendly carbon fiber treatment agent in the preparation of carbon fiber sheets for sports shoes.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The environmentally friendly carbon fiber treatment agent provided by this invention is prepared by modifying a polyurethane resin containing a furan ring with a phenoxy resin and a carboxylic acid-siloxane copolymer containing a maleimide group. This agent is then applied to the surface of carbon fibers to form a surface coating. The aromatic structure of the furan ring has a certain polarity match with the amide group of the polyamide resin, which can promote the interaction between the carbon fiber and the polyamide resin at the interface. Furthermore, the oxygen atom on the furan ring can act as a hydrogen bond acceptor, forming hydrogen bonds with the amide group of the polyamide resin, thus enhancing the interfacial bonding force. The benzene ring and ether bond structure in the phenoxy resin molecule not only endow it with good rigidity and flexibility but also allow it to interact with the amide group of the polyamide resin. Hydrogen bonds are formed, further enhancing the interfacial bonding between carbon fibers and polyamide resin. The maleimide groups in the carboxylic acid-siloxane copolymer containing maleimide groups have high reactivity and can react chemically with the amine or amide groups in the polyamide resin to form a covalent cross-linked network, further enhancing the interfacial bonding strength. At the same time, the introduction of siloxane segments can adjust the surface energy of the carbon fiber surface, reduce the surface tension between the two, and further improve the interfacial compatibility. The combined action of furan rings, phenoxy resin, maleimide groups, and siloxane segments enables the carbon fiber and polyamide resin to form good interfacial wetting and stress transfer effects, thereby effectively improving the mechanical properties of the carbon fiber sheet.

[0028] Meanwhile, carbon fiber plates prepared by treating carbon fiber with environmentally friendly carbon fiber treatment agents contain a large number of polar groups on their surface. These polar groups can interact strongly with the polar groups in the EVA adhesive used to composite the sole substrate and the carbon fiber plate, thereby effectively enhancing the interfacial bonding force between the carbon fiber plate and the sole substrate and improving the stability of high-performance sports shoes containing carbon fiber plates.

[0029] 2. The environmentally friendly carbon fiber treatment agent provided by this invention increases the tensile strength of carbon fiber sheets by >15% and the flexural strength by >20%. Attached Figure Description

[0030] Figure 1 The infrared spectrum of the environmentally friendly carbon fiber treatment agent in Example 4; Figure 2 The image shows a carbon fiber plate prepared using the environmentally friendly carbon fiber treatment agent of Example 4, which is then bonded to a shoe sole substrate with EVA adhesive. The plate was placed for 24 hours before a tensile test was performed. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified in the examples and comparative examples, the conditions were performed under standard conditions or conditions recommended by the manufacturer. All reagents and instruments used were commercially available products unless otherwise specified.

[0033] Example 1

[0034] An environmentally friendly carbon fiber treatment agent, by weight percentage, comprises the following components: 8.8% polyol, 0.1% furan-cyclodiol, 0.8% isocyanate, 26% solvent A, 0.3% catalyst, 0.2% phenoxy resin, 0.1% carboxylic acid-siloxane copolymer containing maleimide groups, and solvent B to make up the balance to 100%.

[0035] The polyol is a polyester polyol based on adipic acid and 1,6-hexanediol, with a number average molecular weight of 3000 and a hydroxyl value of 37±2 mgKOH / g, Huafeng PE-9937D.

[0036] The furan-containing diol is 2,5-furandiethanol.

[0037] The isocyanate is diphenylmethane diisocyanate.

[0038] Solvent A is dimethyl carbonate.

[0039] The catalyst is dibutyltin dilaurate.

[0040] The phenoxy resin has a weight-average molecular weight of 30000±2000 and a solid content of 32±1.5%. It is manufactured by Shengyuan Chemical (Anshan) Co., Ltd., and its model number is TPE2102.

[0041] The preparation method of the carboxylic acid-siloxane copolymer containing maleimide groups is as follows: A carboxylic acid containing a maleimide group is mixed with N,N-dimethylformamide, and then 1,3-bis(3-glycidyl ether oxypropyl)tetramethyldisiloxane and tetrabutylammonium bromide are added. The mixture is heated and stirred to react, and after the reaction is completed, it is subjected to reduced pressure treatment to obtain the final product.

[0042] The carboxylic acid containing the maleimide group is 11-maleamidoundecanoic acid.

[0043] The molar ratio of the carboxylic acid containing the maleimide group and 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane is 1:0.52.

[0044] The mass ratio of the carboxylic acid containing the maleimide group to N,N-dimethylformamide is 1:3.

[0045] The amount of tetrabutylammonium bromide added is 2% of the total weight of the carboxylic acid containing maleimide group and 1,3-bis(3-glycidyl ether oxypropyl)tetramethyldisiloxane.

[0046] The heating and stirring reaction was carried out at a temperature of 85°C for 6 hours.

[0047] Solvent B is butanone, acetone and N-ethyl-2-pyrrolidone in a weight ratio of 3.5:2.5:0.5.

[0048] The preparation method of the above-mentioned environmentally friendly carbon fiber treatment agent includes the following steps: (1) Add polyol, isocyanate and solvent A to the reaction vessel, heat and stir to dissolve to obtain mixture A; (2) Heat mixture A to 90°C, add catalyst under nitrogen protection, and stir for 3 hours to obtain mixture B; (3) First, add furan ring diol and stir for 30 min, then add phenoxy resin and carboxylic acid-siloxane copolymer containing maleimide group, and continue stirring for 2 h to obtain mixture C; (4) Add solvent B and continue stirring for 2 hours to obtain environmentally friendly carbon fiber treatment agent.

[0049] Example 2

[0050] The only difference from Example 1 is that the environmentally friendly carbon fiber treatment agent, by weight percentage, comprises the following components: 8.3% polyol, 0.2% furan cyclodiol, 0.8% isocyanate, 28% solvent A, 0.3% catalyst, 0.3% phenoxy resin, 0.2% carboxylic acid-siloxane copolymer containing maleimide groups, and solvent B to make up the balance to 100%; all other components are the same.

[0051] Example 3

[0052] The only difference from Example 1 is that the environmentally friendly carbon fiber treatment agent, by weight percentage, comprises the following components: 8.1% polyol, 0.3% furan cyclodiol, 0.7% isocyanate, 27% solvent A, 0.3% catalyst, 0.5% phenoxy resin, 0.3% carboxylic acid-siloxane copolymer containing maleimide groups, and solvent B to make up the balance to 100%; all other components are the same.

[0053] Example 4

[0054] The only difference from Example 1 is that the environmentally friendly carbon fiber treatment agent, by weight percentage, comprises the following components: 8.8% polyol, 0.3% furan cyclodiol, 0.9% isocyanate, 26% solvent A, 0.3% catalyst, 0.8% phenoxy resin, 0.4% carboxylic acid-siloxane copolymer containing maleimide groups, and solvent B to make up the balance to 100%; all other components are the same.

[0055] The infrared spectrum of the environmentally friendly carbon fiber treatment agent obtained in this embodiment is as follows: Figure 1 As shown.

[0056] Comparative Example 1 The only difference from Example 4 is that there is no furan-cyclic diol; everything else is the same.

[0057] Comparative Example 2 The only difference from Example 4 is that phenoxy resin is not present; everything else is the same.

[0058] Comparative Example 3 The only difference from Example 4 is that there is no carboxylic acid-siloxane copolymer containing maleimide groups; otherwise, they are the same.

[0059] Comparative Example 4 The only difference from Example 4 is that the furan-containing diol is replaced with 1,4-dihydroxy-2,2-dimethylpiperazine; all other aspects are the same.

[0060] Comparative Example 5 The only difference from Example 4 is that the phenoxy resin is replaced with bisphenol A type epoxy resin E51, Phoenix brand; all other aspects are the same.

[0061] Comparative Example 6 The only difference from Example 4 is that the carboxylic acid-siloxane copolymer containing maleimide groups is replaced with 4-maleimide-phenol and γ-aminopropyltriethoxysilane in a weight ratio of 1:4. The preparation method of the environmentally friendly carbon fiber treatment agent includes the following steps: (1) Add polyol, isocyanate and solvent A to the reaction vessel, heat and stir to dissolve to obtain mixture A; (2) Heat mixture A to 90°C, add catalyst under nitrogen protection, and stir for 3 hours to obtain mixture B; (3) First, add furan ring diol and stir for 30 min, then add phenoxy resin and 4-maleimide phenol, continue stirring for 1 h, then add γ-aminopropyltriethoxysilane and continue stirring for 1 h to obtain mixture C; (4) Add solvent B and continue stirring for 2 hours to obtain an environmentally friendly carbon fiber treatment agent; the rest are the same.

[0062] Comparative Example 7 The only difference from Example 4 is that the environmentally friendly carbon fiber treatment agent includes a polyurethane compound and a phenoxy resin in a weight ratio of 1:1; the polyurethane compound, by weight percentage, includes the following components: 8.8% polyol, 0.9% isocyanate, 26% solvent A, 0.3% catalyst, and solvent B to make up the balance to 100%; the rest are the same.

[0063] Performance Test 1: The environmentally friendly carbon fiber treatment agent and isocyanate hardener (TPTI isocyanate, NCO 5.4%, Hangzhou Brown Biomedical Technology Co., Ltd., HARDLION RF) prepared in the above examples and comparative examples were mixed evenly at a weight ratio of 100:8 and then brushed onto the surface of carbon fiber (Mitsubishi Chemical TR06U, fiber length 6mm), with a coating amount of 90g / m. 2 Then, after heat treatment at 120℃ for 6 hours, it was mixed with PA12 (WANAMID PA12 L3000) at a mass ratio of 10:100, extruded and granulated using a twin-screw extruder, and injection molded into carbon fiber sheets. The following performance tests were then conducted: 1. Interlaminar shear strength: The interlaminar shear strength of carbon fiber plates was determined using a universal tensile tester in accordance with JC / T 773-2010 standard. 2. Mechanical properties: The tensile strength of the carbon fiber sheet was tested and determined according to GB / T 1040.2-2022 standard, and the flexural strength of the carbon fiber sheet was tested according to GB / T 9341-2008. The tensile strength improvement rate and flexural strength improvement rate were calculated.

[0064] Wherein, the tensile strength improvement rate % = (tensile strength of test sample - tensile strength of control sample) / tensile strength of control sample × 100%.

[0065] Bending strength improvement rate % = (bending strength of test sample - bending strength of control sample) / bending strength of control sample × 100%. The control sample is made by mixing untreated carbon fiber (Mitsubishi Chemical TR06U fiber length of 6mm) and PA12 (WANAMID PA12 L3000) at a mass ratio of 10:100, extruding and granulating it through a twin-screw extruder, and then injection molding it.

[0066] The results are shown in Table 1 below.

[0067] Table 1

[0068] As can be seen from the test results in Table 1, the carbon fiber treatment agent obtained by modifying polyurethane with furan cyclic diol, phenoxy resin, and carboxylic acid-siloxane copolymer containing maleimide groups can effectively improve the interfacial bonding force between carbon fiber and polyamide resin and enhance the mechanical properties of carbon fiber sheets. Comparative Examples 1-3, lacking any of the components in the polyurethane containing furan cyclic diol, phenoxy resin, and carboxylic acid-siloxane copolymer containing maleimide groups, showed a significant decrease in interlaminar shear strength and mechanical properties of the obtained carbon fiber sheets. Comparative Examples 4-7, using components similar to those used in furan cyclic diol, phenoxy resin, and carboxylic acid-siloxane copolymer containing maleimide groups to modify polyurethane, failed to achieve the interfacial bonding force and mechanical properties of the obtained carbon fiber sheets compared to Examples 1-3, indicating that the present invention has unexpected technical effects.

[0069] Performance Test 2: The environmentally friendly carbon fiber treatment agent and isocyanate hardener (TPTI isocyanate, NCO 5.4%, Hangzhou Brown Biomedical Technology Co., Ltd., HARDLION RF) prepared in the above examples and comparative examples were mixed evenly at a weight ratio of 100:8 and then brushed onto the surface of carbon fiber (Mitsubishi Chemical TR06U fiber length 6mm), with a coating amount of 90g / m. 2 Then, after heat treatment at 120℃ for 6 hours, it was mixed with PA12 (WANAMID PA12 L3000) at a mass ratio of 10:100, extruded and granulated using a twin-screw extruder, and injection molded into carbon fiber sheets. EVA adhesive was then used to composite the sheets with the shoe sole substrate. After 24 hours of resting, the tensile strength was tested using a high-speed rail servo tensile testing machine. The actual product image after testing in Example 4 is shown below. Figure 2 As shown in the figure. The results are shown in Table 2 below.

[0070] Table 2

[0071] As can be seen from the test results in Table 2, the carbon fiber treatment agent obtained by modifying polyurethane with furan ring diol, phenoxy resin and carboxylic acid-siloxane copolymer containing maleimide group can also effectively improve the interfacial bonding force between carbon fiber plate and shoe sole substrate.

[0072] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An environmentally friendly carbon fiber treatment agent, characterized in that, By weight percentage, it includes the following components: 6-10% polyol, 0.1-0.3% furan-cyclic diol, 0.5-1.5% isocyanate, 20-30% solvent A, 0.2-0.7% catalyst, 0.2-1% phenoxy resin, 0.1-0.4% carboxylic acid-siloxane copolymer containing maleimide groups, and solvent B to make up the balance to 100%.

2. The environmentally friendly carbon fiber treatment agent according to claim 1, characterized in that, The polyol is a polyester polyol based on adipic acid and 1,6-hexanediol, with a number average molecular weight of 3000-3500 and a hydroxyl value of 30-40 mgKOH / g.

3. The environmentally friendly carbon fiber treatment agent according to claim 2, characterized in that, The furan-containing diol is selected from at least one of 2,5-furandiethanol and 2,5-furandipropanol.

4. The environmentally friendly carbon fiber treatment agent according to claim 3, characterized in that, The isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, terephthalic diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, phenylmethylene diisocyanate, and dimethylbiphenyl diisocyanate.

5. The environmentally friendly carbon fiber treatment agent according to any one of claims 1-4, characterized in that, The weight-average molecular weight of the phenoxy resin is 25,000-35,000.

6. The environmentally friendly carbon fiber treatment agent according to any one of claims 1-4, characterized in that, The preparation method of the carboxylic acid-siloxane copolymer containing maleimide groups is as follows: A carboxylic acid containing a maleimide group is mixed with N,N-dimethylformamide, and then 1,3-bis(3-glycidyl ether oxypropyl)tetramethyldisiloxane and tetrabutylammonium bromide are added. The mixture is heated and stirred to react, and after the reaction is completed, it is subjected to reduced pressure treatment to obtain the final product.

7. The environmentally friendly carbon fiber treatment agent according to claim 6, characterized in that, The carboxylic acid containing the maleimide group is selected from at least one of 5-maleimide valerate, 6-maleimide hexanoic acid, and 11-maleamido undecanoic acid.

8. The environmentally friendly carbon fiber treatment agent according to claim 7, characterized in that, The molar ratio of the carboxylic acid containing the maleimide group and 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane is 1:0.45-0.

55.

9. A method for preparing the environmentally friendly carbon fiber treatment agent according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Add polyol, isocyanate and solvent A to the reaction vessel, heat and stir to dissolve to obtain mixture A; (2) Heat mixture A, add catalyst under nitrogen protection, and stir to obtain mixture B; (3) First add furan ring diol and continue stirring, then add phenoxy resin and carboxylic acid-siloxane copolymer containing maleimide group and continue stirring to obtain mixture C; (4) Add solvent B and continue stirring to obtain an environmentally friendly carbon fiber treatment agent.

10. The application of the environmentally friendly carbon fiber treatment agent according to any one of claims 1-8 in the preparation of carbon fiber plates for sports shoes.

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