High-heat-resistance modified polyurethane plastic sizing agent and preparation method thereof

Abstract

The invention relates to a high-heat-resistance modified polyurethane plastic sizing agent and a preparation method thereof, and belongs to the technical field of sizing agents. The high-heat-resistance modified polyurethane plastic sizing agent comprises main slurry and water, and the main slurry comprises modified polyurethane, polyetherimide, an emulsifier and a wetting agent; wherein the mass ratio of the polyetherimide to the modified polyurethane is (0.1-0.5): 1, and the ratio of the total mass of the emulsifier and the wetting agent to the mass of the modified polyurethane is (0.05-0.2): 1; the mass ratio of the emulsifier to the wetting agent is (0.5-2): 1; the modified polyurethane comprises modified polyurethane modified by acrylic acid and acrylic ester derivatives, and the modified polyurethane comprises a copolymer polymerized by acrylic acid, lipid derivatives of acrylic acid, ester derivatives of acrylic acid, isocyanate and dihydric alcohol; the acrylate derivative comprises at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate. The sizing agent with relatively high heat resistance, stability and adhesive force can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of sizing agents, and in particular to a highly heat-resistant modified polyurethane plastic sizing agent and a preparation method thereof. Background Art

[0002] Due to its unique microphase separation structure, polyurethane resin has excellent mechanical properties, wear resistance and low temperature resistance when formed into a film. The sizing agent with polyurethane as the main body can better improve the interface performance between carbon fiber and polyurethane resin matrix.

[0003] At present, the heat resistance of sizing agents based on polyurethane is not high, which cannot meet the application of carbon fiber polyurethane composites at higher working temperatures, and the stability and adhesion of the sizing agents are insufficient. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the embodiments of the present application includes providing a highly heat-resistant modified polyurethane plastic sizing agent and a preparation method thereof, so as to improve the problems of insufficient heat resistance, stability and adhesion of the existing sizing agent based on polyurethane.

[0005] In the first aspect, an embodiment of the present application provides a highly heat-resistant modified polyurethane plastic sizing agent, the sizing agent comprising a main slurry and water, the main slurry comprising modified polyurethane, polyetherimide, an emulsifier and a wetting agent; wherein the mass ratio of polyetherimide to modified polyurethane is 0.1-0.5:1, and the mass ratio of the total mass of the emulsifier and the wetting agent to the modified polyurethane is 0.05-0.2:1; the mass ratio of the emulsifier to the wetting agent is 0.5-2:1; the modified polyurethane comprises a modified polyurethane modified with acrylic acid and acrylate derivatives, the modified polyurethane comprises a copolymer of acrylic acid and its lipid derivatives, ester derivatives, isocyanates and diols; the acrylate derivatives comprise at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate.

[0006] The present application uses modified polyurethane as the main body, and adds polyetherimide of appropriate mass, which can effectively improve the heat resistance of the sizing agent, thereby meeting the application of carbon fiber polyurethane composite materials at higher working temperatures; and the modified polyurethane modified with acrylic acid and acrylate derivatives can be better compatible and mixed with polyetherimide; at the same time, an emulsifier and a wetting agent with an appropriate mass ratio are used. The combination of the emulsifier and the wetting agent can make the components evenly dispersed in water, enhance the emulsification effect, enhance the compatibility between the components, and help improve the stability and adhesion of the sizing agent.

[0007] In some embodiments of the present application, the isocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.

[0008] In some embodiments of the present application, the diol includes at least one of ethylene glycol, propylene glycol, butylene glycol, and neopentyl glycol.

[0009] In some embodiments of the present application, the number average molecular weight of the modified polyurethane is 5000-20000.

[0010] The present application adopts modified polyurethane with a suitable number average molecular weight, so that the modified polyurethane has higher wear resistance and weather resistance.

[0011] In some embodiments of the present application, the polyetherimide includes a polymer of an alkali metal salt of a dihydroxy aromatic compound and bis(halophthalimide).

[0012] In some embodiments of the present application, the alkali metal salt of the dihydroxy aromatic compound includes any one of bisphenol A disodium salt and bisphenol S disodium salt.

[0013] In some embodiments of the present application, the bis(halogenated phthalimide) includes any one of bis(chlorophthalimide), bis(bromophthalimide), bis(iodinated phthalimide), bis(chlorobromophthalimide), and bis(chloroiodinated phthalimide).

[0014] In some embodiments of the present application, the number average molecular weight of the polyetherimide is 40,000-60,000.

[0015] The present application adopts polyetherimide with a suitable number average molecular weight, which can promote the compatibility between polyetherimide and other components, improve the heat resistance of the sizing agent, and also improve the strength and wear resistance of the sizing agent.

[0016] In some embodiments of the present application, the emulsifier includes at least one of dodecyltrimethyl chloride (bromide), castor oil ethylene oxide adducts and acrylic acid derivatives, fatty acid ethylene oxide adducts, polyol fatty acid esters and acrylic acid ethylene oxide adducts, and polyvinyl alcohol.

[0017] The present application adopts at least one of the above emulsifiers to evenly disperse the components in water and enhance the compatibility between the components.

[0018] In some embodiments of the present application, the wetting agent includes at least one of phenethylphenol polyoxyethylene ether polyoxypropylene ether and phenethylphenol polyoxyethylene ether.

[0019] The present application adopts at least one of the above wetting agents to make the components dispersed evenly in water and enhance the compatibility between the components.

[0020] In a second aspect, the present application embodiment provides a method for preparing a highly heat-resistant modified polyurethane plastic sizing agent as in the first aspect, comprising:

[0021] (1) dissolving polyetherimide in an organic solvent to obtain a polyetherimide solution;

[0022] (2) dissolving an emulsifier and a wetting agent in water according to a mass ratio to obtain an emulsifier aqueous solution;

[0023] (3) mixing the modified polyurethane with an emulsifier aqueous solution to obtain a polyurethane emulsion;

[0024] (4) mixing the polyetherimide solution with a portion of the polyurethane emulsion to perform an emulsification reaction to obtain a mixed emulsion;

[0025] (5) Mixing the mixed emulsion with the remaining part of the polyurethane emulsion, adjusting the pH to 6-8, and obtaining a sizing agent.

[0026] In the present application, part of the modified polyurethane is first mixed and emulsified with the polyetherimide solution to form a mixed emulsion, and then mixed with the remaining part of the polyurethane emulsion, so that the components can be evenly dispersed in water, the emulsification effect is good, and the compatibility between the components is good, so that a sizing agent with high stability and adhesion can be prepared.

[0027] In some embodiments of the present application, the organic solvent includes at least one of dichloromethane, methanol, ethanol, isobutanol, acetone, and toluene.

[0028] In some embodiments of the present application, steps (2)-(5) specifically include: dividing the emulsifier aqueous solution into two parts, mixing one part of the emulsifier aqueous solution with the modified polyurethane to obtain a first polyurethane emulsion; dividing the first polyurethane emulsion into two parts, mixing one part of the first polyurethane emulsion with the other part of the emulsifier aqueous solution to obtain a second polyurethane emulsion; mixing the second polyurethane emulsion with the polyetherimide solution to obtain a mixed emulsion; and mixing the mixed emulsion with the other part of the first polyurethane emulsion.

[0029] The present application first divides the emulsifier aqueous solution into two parts, emulsifies the modified polyurethane in two steps, and then mixes the polyetherimide solution with the second polyurethane emulsion to form a mixed emulsion, which is then mixed with the first polyurethane emulsion. This can further make the components evenly dispersed in water, improve the emulsification effect, and improve the compatibility between the components, so as to prepare a sizing agent with higher stability and adhesion.

[0030] In some embodiments of the present application, the mass ratio of the two first polyurethane emulsions is 1:4-26.

[0031] In some embodiments of the present application, the first polyurethane emulsion and the emulsifier aqueous solution are mixed in a mass ratio of 1:1-2.

[0032] In some embodiments of the present application, the method for using the highly heat-resistant modified polyurethane plastic sizing agent is: diluting the sizing agent to a solid content of 0.7%-1.3%.

[0033] The present application dilutes the sizing agent to a solid content of 0.7%-1.3%, which can adjust the viscosity and fluidity of the sizing agent, improve the use efficiency, make the sizing more uniform, save costs and reduce slurry waste, optimize the sizing process and improve the sizing effect of carbon fiber.

[0034] Beneficial Effects

[0035] The present application uses modified polyurethane as the main body, and adds polyetherimide of appropriate mass, which can effectively improve the heat resistance of the sizing agent, thereby meeting the application of carbon fiber polyurethane composite materials at higher working temperatures; and the modified polyurethane modified with acrylic acid and acrylate derivatives can be better compatible and mixed with polyetherimide; at the same time, an emulsifier and a wetting agent with an appropriate mass ratio are used. The combination of the emulsifier and the wetting agent can make the components evenly dispersed in water, enhance the emulsification effect, enhance the compatibility between the components, and help improve the stability and adhesion of the sizing agent. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] The embodiment of the present application provides a highly heat-resistant modified polyurethane plastic sizing agent, the sizing agent includes a main slurry and water, the main slurry includes modified polyurethane, polyetherimide, an emulsifier and a wetting agent; wherein the mass ratio of polyetherimide to modified polyurethane is 0.1-0.5:1, the mass ratio of the total mass of the emulsifier and the wetting agent to the modified polyurethane is 0.05-0.2:1; the mass ratio of the emulsifier to the wetting agent is 0.5-2:1; the modified polyurethane includes modified polyurethane modified with acrylic acid and acrylate derivatives, the modified polyurethane includes a copolymer of acrylic acid and its lipid derivatives, ester derivatives, isocyanate and diol polymerization; the acrylate derivatives include at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate.

[0038] The sizing agent is mainly composed of modified polyurethane, and polyetherimide of appropriate mass is added to effectively improve the heat resistance of the sizing agent, so as to meet the application of carbon fiber polyurethane composite materials at higher working temperatures; and the modified polyurethane modified by acrylic acid and acrylate derivatives can be better compatible and mixed with polyetherimide; at the same time, an emulsifier and a wetting agent with an appropriate mass ratio are used, and the combination of the emulsifier and the wetting agent can make the components evenly dispersed in water, enhance the emulsification effect, enhance the compatibility between the components, and help to improve the stability and adhesion of the sizing agent.

[0039] As an example, the mass ratio of polyetherimide to modified polyurethane can be, but is not limited to, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, and the mass ratio of the total mass of the emulsifier and the wetting agent to the modified polyurethane is 0.05:1, 0.1:1, 0.15:1, 0.2:1.

[0040] Wherein, the isocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate. The diol includes at least one of ethylene glycol, propylene glycol, butanediol, and neopentyl glycol. The number average molecular weight of the modified polyurethane is 5000-20000. Polyurethane is modified by using acrylic acid and acrylate derivatives, and suitable isocyanate and diol are polymerized into polyurethane, and its number average molecular weight is controlled within a suitable range; a modified polyurethane with better compatibility, higher wear resistance and weather resistance can be obtained, which is conducive to obtaining a sizing agent with higher stability and adhesion.

[0041] As an example, the mass ratio of the emulsifier to the wetting agent is 0.5: 1, 1: 1, 1.5: 1, and 2: 1. The emulsifier and the wetting agent can be further evenly dispersed in water by a suitable mass ratio, thereby enhancing the compatibility between the components and improving the stability and adhesion of the sizing agent.

[0042] In some embodiments of the present application, the polyetherimide comprises a polymer of an alkali metal salt of a dihydroxy aromatic compound and bis(halophthalimide). The number average molecular weight of the polyetherimide is 40,000-60,000.

[0043] Wherein, the alkali metal salt of dihydroxy aromatic compound comprises any one of bisphenol A disodium salt and bisphenol S disodium salt. Bis(halogenated phthalimide) comprises any one of bis(chlorophthalimide), bis(bromophthalimide), bis(iodophthalimide), bis(chlorobromophthalimide), bis(chloroiodophthalimide). The alkali metal salt of dihydroxy aromatic compound has good stability and high temperature resistance, and bis(halogenated phthalimide) has excellent mechanical properties and chemical resistance, and the combination of the two is coordinated to make polyetherimide polymer have better stability, high temperature resistance, mechanical properties and chemical resistance. And within the above-mentioned number average molecular weight range, the compatibility between polyetherimide and other components can be promoted, the heat resistance of sizing agent can be improved, and the strength and wear resistance of sizing agent can also be improved.

[0044] In some embodiments of the present application, the emulsifier includes at least one of dodecyltrimethyl chloride (bromide), castor oil ethylene oxide adducts and acrylic acid derivatives, fatty acid ethylene oxide adducts, polyol fatty acid esters and acrylic acid ethylene oxide adducts, and polyvinyl alcohol. The wetting agent includes at least one of phenethylphenol polyoxyethylene ether polyoxypropylene ether and phenethylphenol polyoxyethylene ether. By using at least one of the above emulsifiers and wetting agents, the components can be evenly dispersed in water and the compatibility between the components can be enhanced.

[0045] As an example, the emulsifier is fatty acid ethylene oxide adduct, and the wetting agent is phenethylphenol polyoxyethylene ether polyoxypropylene ether. The emulsifier is specifically fatty acid ethylene oxide adduct, and the wetting agent is specifically phenethylphenol polyoxyethylene ether polyoxypropylene ether, which has a good synergistic effect and effectively improves the stability and adhesion of the sizing agent.

[0046] The preparation method of the above-mentioned highly heat-resistant modified polyurethane plastic sizing agent comprises the following steps:

[0047] (1) dissolving polyetherimide in an organic solvent, and stirring at 200-400 r / min for 1-2 h to obtain a polyetherimide solution;

[0048] (2) dissolving the emulsifier and the wetting agent in water according to the mass ratio, and stirring at 200-400 r / min for 2-3 hours to obtain an emulsifier aqueous solution;

[0049] (3) dividing the emulsifier aqueous solution into two parts, mixing the modified polyurethane with one part of the emulsifier aqueous solution for primary emulsification, stirring at 3000-5000 r / min to obtain a first polyurethane emulsion, dividing the first polyurethane emulsion into two parts at a mass ratio of 1:4-26, and taking one part of the first polyurethane emulsion and mixing it with the other part of the emulsifier aqueous solution at a mass ratio of 1:1-2 for secondary emulsification to obtain a second polyurethane emulsion;

[0050] (4) mixing the polyetherimide solution and the second polyurethane emulsion at 3000-5000 r / min with stirring for 0.5-1 h to carry out an emulsification reaction to obtain a mixed emulsion;

[0051] (5) The mixed emulsion is mixed with another portion of the first polyurethane emulsion by stirring at 500-1000 r / min for 4-6 h, and the pH is adjusted to 6-8 to obtain a sizing agent.

[0052] The present application first divides the emulsifier aqueous solution into two parts, emulsifies the modified polyurethane in two steps, and then mixes the polyetherimide solution with the second polyurethane emulsion to form a mixed emulsion, which is then mixed with the first polyurethane emulsion. This allows the components to be evenly dispersed in water, with good emulsification effect and good compatibility between the components, and can produce a sizing agent with high stability and adhesion.

[0053] The organic solvent may be, but is not limited to, at least one of dichloromethane, methanol, ethanol, isobutanol, acetone, and toluene.

[0054] As an example, the mass ratio of the two first polyurethane emulsions can be, but is not limited to, 1:4, 1:4.5, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, 1:22, 1:24, 1:26. The first polyurethane emulsion and the emulsifier aqueous solution can be, but are not limited to, mixed in a mass ratio of 1:1, 1:1.5, 1:2.

[0055] According to the above conditions, a sizing agent with a particle size of 200-500 nm is prepared, so that the sizing agent is more evenly dispersed, less prone to phase separation or precipitation, has better stability and adhesion, and improves the sizing effect on carbon fiber. Furthermore, the particle size of the prepared sizing agent is 200-400 nm, which can further improve the stability and adhesion of the sizing agent.

[0056] When using the highly heat-resistant modified polyurethane plastic sizing agent, the sizing agent can be diluted to a solid content of 0.7%-1.3%, but is not limited to the dilution. The viscosity and fluidity of the sizing agent can be adjusted, the use efficiency can be improved, the sizing can be made more uniform, the cost can be saved, the sizing waste can be reduced, the sizing process can be optimized, and the sizing effect of the carbon fiber can be improved.

[0057] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0058] The method for synthesizing polyetherimide from bisphenol A disodium salt and bis(bromophthalimide) in the following Example 1 is:

[0059] (1) 0.05 mol of bisphenol A disodium salt and 0.05 mol of bis(bromophthalimide) were placed in a three-necked flask, stirred continuously, the reaction temperature was adjusted to 110° C., and the reaction time was controlled to 2 h to obtain product 1;

[0060] (2) Controlling the temperature to be constant, first add 0.05 mol of NaOH aqueous solution, continue stirring for 1 h, then continue to add 0.05 mol of H2SO4, continue stirring for 0.5 h, wherein NaOH:H2O=4:1, H2SO4:H2O=2:1, remove methylamine and Na2SO4 in the reaction system to obtain product 2;

[0061] (3) Add 0.1 mol of water to the three-necked flask containing product 2, heat to 230°C, and recrystallize for 5 hours to obtain product 3;

[0062] (4) 0.05 mol of the product tris and 0.05 mol of m-phenylenediamine were melt polymerized at 320° C. using a twin-screw extruder to obtain polyetherimide pellets. The number average molecular weight of the final polyetherimide was 52,500.

[0063] In other embodiments, the amount of bisphenol A disodium salt added is controlled within the range of 0.04-0.06 mol to obtain polyetherimide with different molecular weights. Other method steps are the same as those in Embodiment 1.

[0064] The method for synthesizing modified polyurethane from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol in the following Example 1 is:

[0065] (1) 0.099 mol of methyl 2-methacrylate, 0.231 mol of polyether polyol prepolymer and 0.33 mol of toluene diisocyanate were completely dissolved in an organic solvent, N,N-dimethylformamide, the reaction temperature was adjusted to 40° C., and stirred for 3 h;

[0066] (2) Raise the temperature to 70° C. and continue to slowly add 0.33 mol of toluene diisocyanate and 0.066 mol of ethylene glycol to carry out a chain extension reaction; after the addition is completed, cool to 30° C., adjust the viscosity, and stir for 1 hour;

[0067] (3) Methanol was added as a capping agent and stirred for 0.5 h to obtain a modified polyurethane. The final NCO content was 2.8% and the number average molecular weight was 19,000.

[0068] In other embodiments, the amount of ethylene glycol added is changed within the range of 0.033-0.099 mol to obtain modified polyurethanes with different molecular weights. Other method steps are the same as those in Embodiment 1.

[0069] The fatty acid ethylene oxide adducts used in the following examples and comparative examples were purchased from Guangzhou Junxin Chemical Technology Co., Ltd., model AEO-3; phenylethylphenol polyoxyethylene ether polyoxypropylene ether was purchased from Yancheng Chemical Additive Co., Ltd., model Nongru 600; and polypropylene resin was purchased from Ami Far East Commercial Services Co., Ltd., model T30S.

[0070] Example 1

[0071] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0072] (1) dissolving 50 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 52,500) in 25 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0073] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0074] (3) The emulsifier aqueous solution was divided into two parts of 115 g and 50 g, 100 g of modified polyurethane (synthesized from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 19,000) was stirred at 3,000 r / min, and 115 g of the emulsifier aqueous solution was gradually added and mixed for 1 h for primary emulsification to obtain a first polyurethane emulsion, and 50 g of the first polyurethane emulsion was mixed with 50 g of the emulsifier aqueous solution for secondary emulsification to obtain a second polyurethane emulsion;

[0075] (4) stirring the polyetherimide solution at 3000 r / min, adding the second polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0076] (5) The mixed emulsion was mixed with the remaining first polyurethane emulsion, stirred at 500 r / min for 4 h, the pH was adjusted to 6, and the particle size was measured according to GB / T 19077-2016 to obtain a sizing agent with a particle size of 388 nm.

[0077] Example 2

[0078] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0079] (1) dissolving 40 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 49,500) in 20 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0080] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0081] (3) The emulsifier aqueous solution was divided into two parts, 125 g and 40 g, 100 g of modified polyurethane (synthesized from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 17500) was stirred at 3000 r / min, and 125 g of the emulsifier aqueous solution was gradually added and mixed for 1 hour for primary emulsification to obtain a first polyurethane emulsion, and 40 g of the first polyurethane emulsion was mixed with 40 g of the emulsifier aqueous solution for secondary emulsification to obtain a second polyurethane emulsion;

[0082] (4) stirring the polyetherimide solution at 3000 r / min, adding the second polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0083] (5) The mixed emulsion was mixed with the remaining first polyurethane emulsion, stirred at 500 r / min for 4 h, and the pH was adjusted to 6 to obtain a sizing agent with a particle size of 345 nm.

[0084] Example 3

[0085] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0086] (1) dissolving 30 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 56,000) in 15 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0087] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0088] (3) The emulsifier aqueous solution was divided into two parts, 135 g and 30 g, 100 g of modified polyurethane (synthesized from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 14500) was stirred at 3000 r / min, and 135 g of the emulsifier aqueous solution was gradually added and mixed for 1 hour for primary emulsification to obtain a first polyurethane emulsion, and 30 g of the first polyurethane emulsion was mixed with 30 g of the emulsifier aqueous solution for secondary emulsification to obtain a second polyurethane emulsion;

[0089] (4) stirring the polyetherimide solution at 3000 r / min, adding the second polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0090] (5) The mixed emulsion was mixed with the remaining first polyurethane emulsion, stirred at 500 r / min for 4 h, and the pH was adjusted to 6 to obtain a sizing agent with a particle size of 319 nm.

[0091] Example 4

[0092] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0093] (1) dissolving 20 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 44,000) in 10 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0094] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0095] (3) The emulsifier aqueous solution was divided into two parts, 145 g and 20 g, 100 g of modified polyurethane (synthesized from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 16,000) was stirred at 3,000 r / min, and 145 g of the emulsifier aqueous solution was gradually added and mixed for 1 h for primary emulsification to obtain a first polyurethane emulsion, and 20 g of the first polyurethane emulsion was mixed with 20 g of the emulsifier aqueous solution for secondary emulsification to obtain a second polyurethane emulsion;

[0096] (4) stirring the polyetherimide solution at 3000 r / min, adding the second polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0097] (5) The mixed emulsion was mixed with the remaining first polyurethane emulsion, stirred at 500 r / min for 4 h, and the pH was adjusted to 6 to obtain a sizing agent with a particle size of 257 nm.

[0098] Example 5

[0099] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0100] (1) dissolving 10 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 51,500) in 5 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0101] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0102] (3) The emulsifier aqueous solution was divided into two parts, 155 g and 10 g, 100 g of modified polyurethane (synthesized from 2-methyl methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 9500) was stirred at 3000 r / min, and 155 g of the emulsifier aqueous solution was gradually added and mixed for 1 hour for primary emulsification to obtain a first polyurethane emulsion, and 10 g of the first polyurethane emulsion was mixed with 10 g of the emulsifier aqueous solution for secondary emulsification to obtain a second polyurethane emulsion;

[0103] (4) stirring the polyetherimide solution at 3000 r / min, adding the second polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0104] (5) The mixed emulsion was mixed with the remaining first polyurethane emulsion, stirred at 500 r / min for 4 h, and the pH was adjusted to 6 to obtain a sizing agent with a particle size of 232 nm.

[0105] Embodiment 6-9

[0106] Example 6-9 provides a highly heat-resistant modified polyurethane plastic sizing agent, which is different from Example 3 in that the number average molecular weights of the modified polyurethane and polyetherimide are different, as shown in Table 1 for details.

[0107] Example 10

[0108] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, which is different from Embodiment 3 in that the mass ratio of the emulsifier to the wetting agent is 3:1.

[0109] Embodiment 11

[0110] This embodiment provides a highly heat-resistant modified polyurethane plastic sizing agent, and the preparation method thereof is as follows:

[0111] (1) dissolving 30 g of polyetherimide (synthesized from bisphenol A disodium salt and bis(bromophthalimide) with a number average molecular weight of 56,000) in 15 g of dichloromethane, and stirring at 200 r / min for 1 h to obtain a polyetherimide solution;

[0112] (2) dissolving 15 g of fatty acid ethylene oxide adduct and phenethylphenol polyoxyethylene ether polyoxypropylene ether in a mass ratio of 2:1 in 150 g of water, stirring at 200 r / min for 2 h to obtain an emulsifier aqueous solution;

[0113] (3) 100 g of modified polyurethane (synthesized from methyl 2-methacrylate, toluene diisocyanate and ethylene glycol, with an NCO content of 2.8% and a number average molecular weight of 14,500) was stirred at 3,000 r / min, and an emulsifier aqueous solution was gradually added and mixed for 1 h to obtain a polyurethane emulsion;

[0114] (4) stirring the polyetherimide solution at 3000 r / min, adding 60 g of polyurethane emulsion, stirring for 30 min, and performing an emulsification reaction to obtain a mixed emulsion;

[0115] (5) The mixed emulsion was mixed with the remaining polyurethane emulsion, stirred at 500 r / min for 4 h, and the pH was adjusted to 6 to obtain a sizing agent with a particle size of nm.

[0116] Comparative Example 1

[0117] This comparative example provides a sizing agent, which is different from Example 3 in that the modified polyurethane is modified with amino silicone oil; the modified polyurethane is polymerized by amino silicone oil, toluene diisocyanate and ethylene glycol. The specific method is as follows: (1) 0.3 parts of amino silicone oil, 0.7 parts of polyether polyol prepolymer and 1 part of toluene diisocyanate are completely dissolved in the organic solvent N,N-dimethylformamide, the reaction temperature is adjusted to 40-45°C, and stirred for 2-3 hours; (2) the temperature is raised to 70-80°C, and 1 part of toluene diisocyanate and 0.2 parts of ethylene glycol are slowly added to carry out chain extension reaction; after the addition is completed, the temperature is lowered to 30-40°C, the viscosity is adjusted, and stirred for 1 hour; (3) methanol is added as a capping agent, stirred for 0.5 hours, and the modified polyurethane is obtained. The final test NCO content is 2.8%, and the number average molecular weight is 28000.

[0118] Comparative Example 2

[0119] This comparative example provides a sizing agent, which is different from Example 3 in that the modified polyurethane is replaced by water-based polyurethane (composed of Waterborne polyurethane dispersion processing).

[0120] Comparative Example 3

[0121] This comparative example provides a sizing agent, which is different from Example 3 in that no polyetherimide is added.

[0122] Comparative Example 4

[0123] This comparative example provides a sizing agent, which is different from Example 3 in that 60 g of polyetherimide is added.

[0124] Comparative Example 5

[0125] This comparative example provides a sizing agent, which is different from Example 3 in that polyetherimide is replaced by polypropylene resin.

[0126] Comparative Example 6

[0127] This comparative example provides a sizing agent, which is different from Example 3 in that no wetting agent is added.

[0128] Table 1 Sizing agents provided by Examples 1-11 and Comparative Examples 1-6

[0129]

[0130]

[0131] Note: “ / ” in Table 1 means that the component is not included.

[0132] Test Example 1

[0133] This test example tests the stability of the sizing agents prepared in Examples 1-11 and Comparative Examples 1-6. The stability of the sizing agent is determined in accordance with GB / T 11175-2021. The test method is as follows: 200 mL of each sizing agent is placed in a 300 mL centrifuge tube and shaken well. 5 samples are a group of samples. Place it on a fixed rack, place it vertically, adjust the thermostat to 25°C, place it for 20 days, and observe whether there is obvious stratification after taking it out. The results are shown in Table 2.

[0134] Table 2 Stability of sizing agent

[0135]

[0136]

[0137] As shown in Table 2, compared with Example 10 and Example 3, the stability of the sizing agent provided in Example 10 is slightly poor, because the mass ratio of the emulsifier and the wetting agent increases, and the sizing agent is slightly stratified. Comparing Example 11 with Example 3, the stability of the sizing agent provided in Example 11 is slightly poor, because the emulsifier aqueous solution is not divided into two parts to emulsify the modified polyurethane twice when the sizing agent is prepared in Example 11, and the dispersion of each component in water is not particularly uniform. Comparing Comparative Example 1 with Example 3, the stability of the sizing agent provided in Comparative Example 1 is slightly poor, because Comparative Example 1 uses amino silicone oil modified polyurethane, which is slightly less water-soluble and is not very uniformly dispersed in water. Comparing Comparative Example 6 with Example 3, the stability of the sizing agent provided in Comparative Example 6 is slightly poor, because no wetting agent is added to the sizing agent in Comparative Example 6, and the dispersion of each component is weakened.

[0138] Test Example 2

[0139] This test example tests the heat resistance, glue content, hair grade and tensile strength of the sizing agents prepared in Examples 1-11 and Comparative Examples 1-6 for carbon fibers. The specific method is as follows: the carbon fibers are sizing treated by the dipping-drying method, the unsized carbon fibers are placed on an unwinding rack, and sequentially passed through a tension roller group, a sizing tank, a drying roller, a drying furnace and a winding machine, the tension is adjusted to 30N, the sizing tank glue tank concentration is 1.3%, the glue tank temperature is 30°C, the drying roller temperature is 135°C, the drying furnace temperature is 210°C, the winding speed is 60m / s, and the sized carbon fibers are obtained after winding.

[0140] Among them, the heat resistance is measured with reference to GB / T 33047.1-2016. The glue content is measured with reference to GB / T29761-2013.

[0141] The fuzz (appearance) is measured with reference to GB / T 26752-2020, and the fuzz grades are defined as follows: Grade 1 is the best, with no obvious fuzz on the surface of the finished carbon fiber, regular tows, and no adhesion between tows; Grade 2 is fuzz, the carbon fiber has slight fuzz, regular tows, and no obvious adhesion between tows; Grade 3 is fuzz, there are more fuzz on the surface of the carbon fiber, and there is no adhesion between tows; Grade 4 is fuzz, there is obvious fuzz on the surface of the carbon fiber, the tows are crossed, and the tows are adhered; Grade 5 is the worst, there is obvious fuzz on the surface of the carbon fiber, the tows are obviously crossed, the adhesion is serious, and the fiber withdrawal is difficult.

[0142] The tensile strength is measured with reference to GB / T 3362-2017. The definition of the tensile strength grades is as follows: the tensile strength of 4500-4600MPa is grade 5, 4600-4700MPa is grade 4, 4700-4800MPa is grade 3, 4800-4900MPa is grade 2, and above 4900MPa is grade 1.

[0143] Thermoplastic sizing agents must meet the requirements of particle size of 200-400nm, heat resistance of not less than 300℃, fiber rubber content of 0.7%-1.3%, hairy appearance of excellent grade 2 or above, strength of 4800MPa and tensile strength of grade 2 or above.

[0144] The results are shown in Table 3.

[0145] Table 3 Performance

[0146]

[0147]

[0148] As shown in Table 3, compared with Example 1-3, the heat resistance of the sizing agent provided in Example 4-5 is reduced to a certain extent because the content of polyetherimide in the sizing agent provided in Example 4-5 is reduced. Compared with Example 1-3, the heat resistance of the sizing agent provided in Example 6 is reduced to a certain extent because the molecular weight of the polyetherimide in the sizing agent provided in Example 6 is relatively small.

[0149] Comparing Examples 10-11, Comparative Example 1 and Example 3, after the sizing agent provided by Examples 10-11 and Comparative Example 1 is used for carbon fiber, the fuzziness grade and tensile strength grade are reduced to a certain extent. This is because the stability of the sizing agent provided by Examples 10-11 and Comparative Example 1 is slightly poor, and polyetherimide is easily adsorbed on the carbon fiber.

[0150] Comparing Comparative Example 2 with Example 3, the heat resistance of the sizing agent provided in Comparative Example 2 is reduced to a certain extent because the sizing agent provided in Comparative Example 2 uses the third generation waterborne polyurethane, which has poor heat resistance.

[0151] Comparing Comparative Example 3 with Example 3, the heat resistance of the sizing agent provided in Comparative Example 3 is reduced, and after being used for carbon fiber, the hairiness level is reduced to a certain extent, because polyetherimide is not added to the sizing agent provided in Comparative Example 3.

[0152] Comparing Comparative Example 4 and Example 3, the heat resistance of the sizing agent provided in Comparative Example 4 is improved, but after being used in carbon fiber, the hairiness grade and tensile strength grade are reduced to a certain extent. This is because the sizing agent provided in Comparative Example 4 contains a large amount of polyetherimide, which can significantly improve the heat resistance but is not conducive to application on carbon fiber.

[0153] Comparing Comparative Example 5 with Example 3, the heat resistance of the sizing agent provided in Comparative Example 5 is reduced, and after being used for carbon fiber, the tensile strength grade is reduced to a certain extent. This is because the polyetherimide in the sizing agent provided in Comparative Example 5 is replaced by polypropylene resin, which cannot achieve the heat resistance of polyetherimide.

[0154] Comparing Comparative Example 6 with Example 3, after the sizing agent provided in Comparative Example 6 is used for carbon fiber, the hairiness level is reduced to a certain extent. This is because no wetting agent is added to the sizing agent provided in Comparative Example 6, and the stability of the sizing agent is slightly poor.

[0155] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A highly heat-resistant modified polyurethane plastic sizing agent, characterized in that: The sizing agent comprises a main slurry and water, wherein the main slurry comprises modified polyurethane, polyetherimide, an emulsifier and a wetting agent; wherein the mass ratio of the polyetherimide to the modified polyurethane is 0.1-0.5:1, the mass ratio of the total mass of the emulsifier and the wetting agent to the modified polyurethane is 0.05-0.2:1; and the mass ratio of the emulsifier to the wetting agent is 0.5-2:1; The modified polyurethane includes modified polyurethane modified by acrylic acid and acrylic acid ester derivatives, and the modified polyurethane includes a copolymer of acrylic acid and acrylic acid and its lipid derivatives, ester derivatives, isocyanate and diol polymerization; the acrylic acid ester derivatives include at least one of methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate.

2. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 1, characterized in that: The isocyanate includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate; And / or, the diol includes at least one of ethylene glycol, propylene glycol, butylene glycol and neopentyl glycol.

3. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 1 or 2, characterized in that: The number average molecular weight of the modified polyurethane is 5000-20000.

4. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 1, characterized in that: The polyetherimide includes a polymer of an alkali metal salt of a dihydroxy aromatic compound and a bis(halophthalimide).

5. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 4, characterized in that: The alkali metal salt of the dihydroxy aromatic compound includes any one of bisphenol A disodium salt and bisphenol S disodium salt; And / or, the bis(halogenated phthalimide) includes any one of bis(chlorophthalimide), bis(bromophthalimide), bis(iodinated phthalimide), bis(chlorobromophthalimide), and bis(chloroiodinated phthalimide).

6. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 4 or 5, characterized in that: The number average molecular weight of the polyetherimide is 40,000-60,000.

7. The highly heat-resistant modified polyurethane plastic sizing agent according to claim 1, characterized in that: The emulsifier includes at least one of dodecyltrimethyl chloride (bromide), castor oil ethylene oxide adduct and acrylic acid derivatives, fatty acid ethylene oxide adduct, polyol fatty acid ester and acrylic acid ethylene oxide adduct, and polyvinyl alcohol; And / or, the wetting agent includes at least one of phenethylphenol polyoxyethylene ether polyoxypropylene ether and phenethylphenol polyoxyethylene ether.

8. A method for preparing a highly heat-resistant modified polyurethane plastic sizing agent according to any one of claims 1 to 7, characterized in that: include: (1) dissolving the polyetherimide in an organic solvent to obtain a polyetherimide solution; (2) dissolving the emulsifier and the wetting agent in water according to a mass ratio to obtain an emulsifier aqueous solution; (3) mixing the modified polyurethane with the emulsifier aqueous solution to obtain a polyurethane emulsion; (4) mixing the polyetherimide solution with a portion of the polyurethane emulsion to perform an emulsification reaction to obtain a mixed emulsion; (5) Mixing the mixed emulsion with the remaining part of the polyurethane emulsion, adjusting the pH to 6-8, and obtaining a sizing agent.

9. The preparation method according to claim 8, characterized in that: The steps (2) to (5) specifically include: dividing the emulsifier aqueous solution into two parts, mixing one part of the emulsifier aqueous solution with the modified polyurethane to obtain a first polyurethane emulsion; dividing the first polyurethane emulsion into two parts, mixing one part of the first polyurethane emulsion with the other part of the emulsifier aqueous solution to obtain a second polyurethane emulsion; mixing the second polyurethane emulsion with the polyetherimide solution to obtain a mixed emulsion; and mixing the mixed emulsion with the other part of the first polyurethane emulsion.

10. The preparation method according to claim 9, characterized in that: The mass ratio of the two parts of the first polyurethane emulsion is 1:4-26; And / or, the first polyurethane emulsion is mixed with the emulsifier aqueous solution in a mass ratio of 1:1-2.

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