Modified polyurethane and bisphenol a polyglyceryl-polyurethane sizing agent and method of preparation

Abstract

The application provides a modified polyurethane and bisphenol A polyglycerol-polyurethane carbon fiber sizing agent and a preparation method. The modified polyurethane comprises a water-based emulsifier structural unit and a polyurethane structural unit, the water-based emulsifier structural unit is derived from a compound shown in formula (I), and the polyurethane structural unit is derived from a reaction product of toluene diisocyanate, polyether and capped polyether. The sizing agent comprises a modified polyurethane resin, a plasticizer, a curing agent and water. The sizing amount of the sizing agent is moderate, the saturated water absorption is low, the interlaminar shear strength is moderate, the particle size is controllable, and the stability is good.

Description

Technical Field

[0001] This invention relates to the field of fiber manufacturing, and more specifically, to a modified polyurethane and bisphenol A polyglycerol-polyurethane sizing agent and its preparation method. Background Technology

[0002] Carbon fiber is a fibrous material composed of carbon elements. Its main application is in the synthesis of carbon fiber reinforced polymer (CFRP) composites with matrices such as resins, metals, and ceramics. Carbon fiber, with its low density, high specific strength, and high specific modulus, imparts excellent mechanical properties to composite materials.

[0003] Polyurethane is a heterochain polymer with urethane characteristic groups. It is a high-molecular-weight material between plastics and rubber, characterized by high elongation, a wide hardness range, and a large range of formulation adjustments. The isocyanate and urethane groups in polyurethane contribute to its excellent adhesive properties and it can be used as a raw material to prepare slurries, coatings, and adhesives. Toluene diisocyanate and polypropylene glycol are commonly used as raw materials for polyurethane. Toluene diisocyanate acts as a hard segment to increase the rigidity and thermal stability of polyurethane, while polypropylene glycol acts as a soft segment to improve its hydrophilicity and flexibility. Due to the difference in hydrophilicity between the hard and soft segments within polyurethane, when the self-emulsifying properties of the polyurethane molecular chain are insufficient, it is necessary to add emulsifiers or adjust the type and ratio of hydrophilic segments to improve the emulsifying properties. The surface of carbon fiber is primarily composed of carbon atoms with few active groups, making it difficult for polyurethane to bond tightly with it. Therefore, designing sizing agents suitable for carbon fiber / polyurethane composites is a current research hotspot.

[0004] Bisphenol A polyether polyols are important products in the synthesis of bisphenol A as a starting material and play a vital role in the field of synthetic resins. Bisphenol A polyether polyols can be used as monomers to synthesize resins or as modifiers and additives for polymers. Grafting bisphenol A polyether polyols into the molecular chain of polymers can endow the polymers with better mechanical strength, elasticity, adhesion, and processability, and the resulting polymers can be used in automotive manufacturing, electrical and electronic fields, etc. Patent JP0493077A2 discloses a method for bonding hydroxyethylated bisphenol A into polymers, giving the polymers better strength, elasticity, adhesion, and processability. Patent CN110130109A discloses a sizing agent for carbon fibers whose main components are polyurethane and polyether. This sizing agent is prepared by uniformly mixing bisphenol A polyether, polyurethane, and higher fatty alcohols to form a sizing agent bath, followed by sizing using an impregnation method. The resulting carbon fibers exhibit excellent wear resistance and fiber opening properties. Similar to most existing technologies, this patent combines bisphenol A polyether and polyurethane to prepare an emulsion. The preparation method used has advantages such as wide applicability and simple synthesis; however, it also has limitations. Firstly, this type of sizing agent uses commercially available resins and epoxy resins, whose raw material properties are fixed and cannot be adapted to carbon fibers. Secondly, this type of sizing agent mostly adopts a physical blending method, resulting in low concentrations and insufficient stability. Furthermore, the van der Waals forces between resin molecules are weak, which is not conducive to the synergistic effect between components. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention first provides a modified polyurethane (i.e., bisphenol A polyglycerol-polyurethane), and then mixes bisphenol A polyglycerol-polyurethane, plasticizer, curing agent and water to prepare a bisphenol A polyglycerol-polyurethane sizing agent. This sizing agent has an adjustable main agent configuration and strong hydrophilicity and wear resistance, thus having excellent application prospects in the field of composite material preparation.

[0006] The sizing agent described in this invention can effectively improve the properties of carbon fibers and enhance the interfacial properties between carbon fibers and polyether and polyurethane resin matrices. The sizing agent exhibits good stability and effectively improves the processing performance of carbon fibers. In practical applications, this invention can be applied to different types of resin matrices by modifying the structure of the main agent and the proportions of its components.

[0007] One objective of this invention is to provide a modified polyurethane comprising an aqueous emulsifier structural unit and a polyurethane structural unit, wherein the aqueous emulsifier structural unit is derived from the compound shown in formula (I):

[0008]

[0009] m and n are the degrees of polymerization, where m is 2 to 10 and n is 1 to 5;

[0010] R1 is R3;

[0011] R2 is R3;

[0012] R3 is -OH,

[0013] R4 is x is 2 to 3;

[0014] R5 and R6 are independent. y is 1 to 2;

[0015] The polyurethane structural units are derived from the polymerization products of toluene diisocyanate, polyether, and capped polyether.

[0016] A second objective of this invention is to provide a method for preparing the modified polyurethane, comprising the following steps:

[0017] Step a) React polyglycerol and bisphenol A to obtain bisphenol A polyglycerol copolymer;

[0018] Step b) The bisphenol A polyglycerol copolymer is modified with a modifier and then dialyzed to obtain an aqueous emulsifier;

[0019] Step c) React the aqueous emulsifier, toluene diisocyanate, polyether and end-capped polyether to obtain the modified polyurethane.

[0020] Preferably, step a) of the preparation method of the present invention includes: mixing polyglycerol, bisphenol A, potassium carbonate and solvent to react, washing the filter cake with ethanol, and drying to obtain bisphenol A polyglycerol copolymer.

[0021] Wherein, the polyglycerol is at least one of diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol, octaglycerol, nonaglycerol, and decaglycerol;

[0022] The molar ratio of polyglycerol to bisphenol A is (0.5-3):1, preferably (1-2):1;

[0023] The reaction temperature is 80–120℃, and the reaction time is 12–36 hours;

[0024] The solvent is preferably diethyl carbonate;

[0025] The molar ratio of potassium carbonate, solvent and bisphenol A is (0.1-2):(1-20):1, preferably (0.2-1):(3-10):1.

[0026] Preferably, step b) of the preparation method of the present invention includes: mixing bisphenol A polyglycerol copolymer, sodium hydroxide and ethanol, adding a modifier solution, carrying out a modification reaction, distilling under reduced pressure to obtain a crude product, dialysis separation, and drying to obtain an aqueous emulsifier.

[0027] The modifier is at least one of dimethylaminochloroethane, 3-(dimethylamino)chloropropane, and diethylaminochloroethane.

[0028] The molar ratio of the modifier to the bisphenol A polyglycerol copolymer is (0.2-3):1, preferably (0.5-2):1;

[0029] The temperature of the modification reaction is 40–80℃, and the reaction time is 2–6 hours.

[0030] The molar ratio of sodium hydroxide and ethanol to bisphenol A polyglycerol copolymer is (1-3):(10-20):1.

[0031] Preferably, step c) of the preparation method of the present invention includes: mixing an aqueous emulsifier with polyether and end-capped polyether at 30-50°C, adding toluene diisocyanate, reacting for 1-3 hours, then raising the temperature to 70-90°C and continuing the reaction for 4-24 hours.

[0032] Wherein, the polyether is polypropylene glycol, and the molecular weight of the polyether is 200 to 2000;

[0033] The end-capped polyether is at least one of polypropylene glycol monomethyl ether, polypropylene glycol monoethyl ether, polypropylene glycol mono-n-propyl ether, and polypropylene glycol monobutyl ether, and the molecular weight of the end-capped polyether is 200 to 2000.

[0034] The molar ratio of polyether, end-capped polyether, toluene diisocyanate and aqueous emulsifier is (0.1-5):(0.1-5):(0.1-4):1, preferably (0.2-2):(0.2-2):(0.4-2):1.

[0035] A third objective of this invention is to provide a modified polyurethane obtained by the aforementioned preparation method.

[0036] The fourth objective of this invention is to provide a bisphenol A polyglycerol-polyurethane sizing agent, comprising the modified polyurethane, plasticizer, curing agent and water.

[0037] The plasticizer is preferably at least one of dioctyl adipate, dioctyl phthalate, diisononyl phthalate, and dioctyl sebacate; the curing agent is preferably at least one of 4-hydroxybenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, and 2-hydroxybenzenesulfonic acid.

[0038] The fifth objective of this invention is to provide a method for preparing the bisphenol A polyglycerol-polyurethane sizing agent, comprising mixing modified polyurethane, plasticizer, curing agent and water, and homogenizing and dispersing them to form an emulsion.

[0039] The molar ratio of plasticizer, curing agent and modified polyurethane is (0.02-2):(0.01-1):1, preferably (0.05-1):(0.02-0.5):1.

[0040] The solid content of the sizing agent is 10-50 wt%.

[0041] Preferably, high-speed homogeneous dispersion is performed, and the rotation speed can be, for example, 7000 to 11000 rpm.

[0042] The prepared bisphenol A polyglycerol-polyurethane sizing agent was diluted to 1-3% and used in the carbon fiber production line for sizing treatment of carbon fibers. The fibers were then dried at 120-150℃ and wound up.

[0043] The above-mentioned sizing agent has a moderate sizing amount (0.4-1.8%), low saturated water absorption rate (<0.2%), moderate interlaminar shear strength (70-110MPa), controllable particle size (200-500nm), and good stability (>6 months).

[0044] The bisphenol A polyglycerol-polyurethane sizing agent of this invention exhibits good compatibility with commonly used polyurethane resin matrices. It simultaneously protects the carbon fiber surface, enhances the interfacial strength between the carbon fiber and the resin matrix, and matches the carbon fiber processing parameters, thereby endowing the carbon fiber with excellent wear resistance, outstanding mechanical properties, and sufficient interfacial strength. The preparation process of this invention has low requirements and controllable costs, fully meeting market demands.

[0045] The features of this invention are:

[0046] (1) Bisphenol A polyglycerol polymers, which are waterborne emulsifiers, have aromatic rings and polyglycerol structures. The aromatic rings and polyglycerols provide rigidity and toughness to the polymer, respectively. Since polyglycerol is a hydrophilic group, bisphenol A polyglycerol polymers have excellent water solubility. The polarity of the polymer can be adjusted by changing the copolymerization ratio of polyether and polyurethane. Adding a modifier can make it form a stable emulsion in water, thereby providing a waterborne emulsifier for polyurethane.

[0047] (2) The raw materials for polyurethane in the main agent are toluene diisocyanate, polyether and end-capped polyether, which react in an aqueous emulsifier. The composition and ratio of the raw materials can be adjusted according to the resin used in the composite material. End-capped polyether is used to control the degree of polymerization of polyurethane and adjust the molecular weight of polyether so that the main agent can form a stable emulsion in water.

[0048] (3) The plasticizer and curing agent used in the sizing agent can further adjust the performance of the emulsion and improve the interfacial performance between the resin and the carbon fiber, thereby obtaining a high-performance carbon fiber reinforced composite material. Detailed Implementation

[0049] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0050] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0051] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0052] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0053] According to a preferred embodiment of the present invention, the preparation method of the bisphenol A polyglycerol-polyurethane sizing agent includes the following steps:

[0054] Step a) At room temperature, based on the molar amount of bisphenol A added, polyglycerol, bisphenol A, potassium carbonate, and diethyl carbonate are added to the reactor sequentially according to the molar ratio of polyglycerol to bisphenol A of 0.5:1 to 3:1, the molar ratio of potassium carbonate to bisphenol A of 0.1:1 to 2:1, and the molar ratio of diethyl carbonate to bisphenol A of 1:1 to 20:1. After reacting at 80 to 120°C for 12 to 36 hours, diethyl carbonate and the water generated in the reaction are removed by vacuum distillation. Ethanol is added to the reactor according to the molar ratio of ethanol to bisphenol A of 50:1 to 200:1. After standing for 1 to 3 hours, the mixture is filtered. The filter cake is washed with ethanol at a molar ratio of 5:1 to 20:1 with bisphenol A each time, and after washing 2 to 3 times, the filtrates are combined, the ethanol is removed by vacuum distillation, and the mixture is vacuum dried at 40 to 80°C for 1 to 3 hours to obtain the bisphenol A polyglycerol copolymer.

[0055] Step b) At room temperature, based on the molar amount of bisphenol A polyglycerol copolymer added, prepare a modifier solution by mixing the modifier and water at a molar ratio of 0.2:1 to 3:1 and a molar ratio of water to bisphenol A polyglycerol copolymer of 10:1 to 30:1. Add the bisphenol A polyglycerol copolymer, sodium hydroxide, and ethanol to the reactor at a molar ratio of 1:1 to 3:1 and a molar ratio of ethanol to bisphenol A polyglycerol copolymer of 10:1 to 20:1. After stirring the mixture evenly, add the modifier solution at 40 to 80°C and react for 2 to 6 hours. Remove ethanol and water by vacuum distillation to obtain a crude product. Place the crude product into a dialysis bag with a molecular weight cutoff of 500 Da and dialyze it in deionized water for 24 to 72 hours to obtain the dialysate. Remove water by vacuum distillation and vacuum dry at 40 to 80°C for 1 to 3 hours to obtain an aqueous emulsifier.

[0056] Step c) At 30–50°C, based on the molar amount of the added aqueous emulsifier, the aqueous emulsifier, polyether, and end-capped polyether are added to the reactor at a molar ratio of 0.1:1 to 5:1 for polyether to aqueous emulsifier and a molar ratio of 0.1:1 to 5:1 for end-capped polyether to aqueous emulsifier. After stirring evenly, toluene diisocyanate is added to the reactor at a molar ratio of 0.1:1 to 4:1 for toluene diisocyanate to aqueous emulsifier. After reacting for 1–3 hours, the temperature is raised to 70–90°C and the reaction continues for 4–24 hours to obtain the bisphenol A polyglycerol-polyurethane copolymer (modified polyurethane) as shown in formula (I).

[0057] Step d) At room temperature, deionized water is added to the bisphenol A polyglycerol-polyurethane copolymer to dilute the mixture to a solid content of 10% to 50%. The mixture is prepared into an emulsion using a high-speed homogenizer with a molar ratio of plasticizer to bisphenol A polyglycerol-polyurethane copolymer of 0.02:1 to 2:1 and a molar ratio of curing agent to bisphenol A polyglycerol-polyurethane copolymer of 0.01:1 to 1:1, to obtain a bisphenol A polyglycerol-polyurethane sizing agent.

[0058] In step a) of the preparation method of the above-mentioned sizing agent, the polyglycerol mentioned is at least one of diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol, octaglycerol, nonaglycerol, and decaglycerol. The modifier mentioned in step b) is one of dimethylaminochloroethane, 3-(dimethylamino)chloropropane, and diethylaminochloroethane. The polyether mentioned in step c) is polypropylene glycol with a molecular weight between 200 and 2000, and the polyether-terminated polypropylene glycol monomethyl ether, polypropylene glycol monoethyl ether, polypropylene glycol mono-n-propyl ether, and polypropylene glycol monobutyl ether have a molecular weight between 200 and 2000. The plasticizer mentioned in step d) is at least one of dioctyl adipate, dioctyl phthalate, diisononyl phthalate, and dioctyl sebacate, and the curing agent is at least one of 4-hydroxybenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, and 2-hydroxybenzenesulfonic acid.

[0059] Test method:

[0060] The sizing amount and saturated water absorption rate of the sized carbon fiber were tested, and the interlaminar shear strength (ILSS) test was carried out in accordance with JC / T773-2010.

[0061] Example 1:

[0062] At 25°C, 30.35g decaglycerol (MW758), 4.57g bisphenol A, 1.38g potassium carbonate, and 15.03g diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100g ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10g ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 31.39g of bisphenol A decaglycerol.

[0063] At 25°C, 2.44 g of dimethylaminochloroethane and 5 g of water were mixed to prepare a modifier solution. 25.65 g of bisphenol A decaglycerol, 1.29 g of sodium hydroxide and 10 g of ethanol were added to the reactor. After stirring the mixture evenly, the temperature was raised to 60°C and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60°C for 2 hours to obtain 28.09 g of water-based emulsifier.

[0064] At 40°C, 18.54g of aqueous emulsifier, 1.02g of tripropylene glycol and 1.09g of tripropylene glycol monomethyl ether were added to the reactor and stirred until homogeneous. Then, 1.39g of toluene diisocyanate was added. After reacting for 2 hours, the temperature was raised to 80°C and reacted for 6 hours to obtain 22.04g of bisphenol A deca-polyglycerol-polyurethane copolymer.

[0065] At 25°C, water was added to the prepared bisphenol A decaglycerol-polyurethane copolymer to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then emulsified using a high-speed homogenizing dispersant to obtain 114.4g of bisphenol A decaglycerol-polyurethane sizing agent.

[0066] The bisphenol A decaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 1.5%, the saturated water absorption rate was 0.12%, and the ILSS was 95 MPa.

[0067] Example 2:

[0068] At 25°C, 18.49 g of hexaglycerol (MW462), 4.57 g of bisphenol A, 1.38 g of potassium carbonate, and 15.03 g of diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100 g of ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10 g of ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 20.75 g of bisphenol A hexaglycerol.

[0069] At 25℃, 2.44g of dimethylaminochloroethane and 5g of water were mixed to prepare a modifier solution. 16.76g of bisphenol A hexaglycerol, 1.29g of sodium hydroxide and 10g of ethanol were added to the reactor. After the mixture was stirred evenly, the temperature was raised to 60℃ and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60℃ for 2 hours to obtain 19.2g of aqueous emulsifier.

[0070] At 40°C, 11.88g of aqueous emulsifier, 1.02g of tripropylene glycol and 1.09g of tripropylene glycol monomethyl ether were added to a reactor and stirred until homogeneous. Then, 1.39g of toluene diisocyanate was added. After reacting for 2 hours, the temperature was raised to 80°C and reacted for 6 hours to obtain 15.38g of bisphenol A hexaglycerol-polyurethane copolymer.

[0071] At 25°C, water was added to the prepared bisphenol A hexaglycerol-polyurethane copolymer to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then emulsified using a high-speed homogenizing dispersant to obtain 81.1g of bisphenol A hexaglycerol-polyurethane sizing agent.

[0072] The bisphenol A hexaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 1.3%, the saturated water absorption rate was 0.11%, and the ILSS was 97 MPa.

[0073] Example 3:

[0074] At 25°C, 30.35g decaglycerol (MW758), 4.57g bisphenol A, 1.38g potassium carbonate, and 15.03g diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100g ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10g ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 31.39g of bisphenol A decaglycerol.

[0075] At 25°C, 4.88 g of dimethylaminochloroethane and 5 g of water were mixed to prepare a modifier solution. 25.65 g of bisphenol A decaglycerol, 1.29 g of sodium hydroxide and 10 g of ethanol were added to the reactor. After the mixture was stirred evenly, the temperature was raised to 60°C and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60°C for 2 hours to obtain 30.53 g of water-based emulsifier.

[0076] At 40°C, 20.53g of aqueous emulsifier, 1.02g of tripropylene glycol and 1.09g of tripropylene glycol monomethyl ether were added to a reactor and stirred until homogeneous. Then, 1.39g of toluene diisocyanate was added. After reacting for 2 hours, the temperature was raised to 80°C and reacted for 6 hours to obtain 24.03g of bisphenol A deca-polyglycerol-polyurethane copolymer.

[0077] At 25°C, water was added to the prepared bisphenol A decaglycerol-polyurethane copolymer to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then emulsified using a high-speed homogenizing dispersant to obtain 124.35g of bisphenol A decaglycerol-polyurethane sizing agent.

[0078] The bisphenol A decaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 1.6%, the saturated water absorption rate was 0.13%, and the ILSS was 97 MPa.

[0079] Example 4:

[0080] At 25°C, 30.35g decaglycerol (MW758), 4.57g bisphenol A, 1.38g potassium carbonate, and 15.03g diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100g ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10g ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 31.39g of bisphenol A decaglycerol.

[0081] At 25°C, 2.44 g of dimethylaminochloroethane and 5 g of water were mixed to prepare a modifier solution. 25.65 g of bisphenol A decaglycerol, 1.29 g of sodium hydroxide and 10 g of ethanol were added to the reactor. After stirring the mixture evenly, the temperature was raised to 60°C and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60°C for 2 hours to obtain 28.09 g of water-based emulsifier.

[0082] At 40°C, 18.54g of aqueous emulsifier, 2.25g of polypropylene glycol (ppg-400) and 1.09g of tripropylene glycol monomethyl ether were added to a reactor. After stirring evenly, 1.39g of toluene diisocyanate was added. After reacting for 2 hours, the temperature was raised to 80°C and reacted for 6 hours to obtain 23.27g of bisphenol A deca-polyglycerol-polyurethane copolymer.

[0083] At 25°C, water was added to the prepared bisphenol A decaglycerol-polyurethane copolymer to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then emulsified using a high-speed homogenizing dispersant to obtain 120.55g of bisphenol A decaglycerol-polyurethane sizing agent.

[0084] The bisphenol A decaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 1.4%, the saturated water absorption rate was 0.13%, and the ILSS was 99 MPa.

[0085] Example 5:

[0086] At 25°C, 30.35g decaglycerol (MW758), 4.57g bisphenol A, 1.38g potassium carbonate, and 15.03g diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100g ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10g ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 31.39g of bisphenol A decaglycerol.

[0087] At 25°C, 2.44 g of dimethylaminochloroethane and 5 g of water were mixed to prepare a modifier solution. 25.65 g of bisphenol A decaglycerol, 1.29 g of sodium hydroxide and 10 g of ethanol were added to the reactor. After stirring the mixture evenly, the temperature was raised to 60°C and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60°C for 2 hours to obtain 28.09 g of water-based emulsifier.

[0088] At 40°C, 18.54g of aqueous emulsifier, 2.04g of tripropylene glycol and 2.18g of tripropylene glycol monomethyl ether were added to a reactor and stirred until homogeneous. Then, 2.78g of toluene diisocyanate was added. After reacting for 2 hours, the temperature was raised to 80°C and reacted for 6 hours to obtain 25.54g of bisphenol A deca-polyglycerol-polyurethane copolymer.

[0089] At 25°C, water was added to the prepared bisphenol A decaglycerol-polyurethane copolymer to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then emulsified using a high-speed homogenizing dispersant to obtain 131.9g of bisphenol A decaglycerol-polyurethane sizing agent.

[0090] The bisphenol A decaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 1.2%, the saturated water absorption rate was 0.11%, and the ILSS was 101 MPa.

[0091] Comparative example:

[0092] At 25°C, 30.35g decaglycerol (MW758), 4.57g bisphenol A, 1.38g potassium carbonate, and 15.03g diethyl carbonate were added to a reactor. After reacting at 110°C for 24 hours, the diethyl carbonate and water produced in the reaction were removed by vacuum distillation. 100g ethanol was added to the reactor, and the mixture was allowed to stand for 2 hours. The mixture was then filtered, and the filter cake was washed with 10g ethanol each time. After washing three times, the filtrates were combined, the ethanol was removed by vacuum distillation, and the mixture was dried under vacuum at 60°C for 1 hour to obtain 31.39g of bisphenol A decaglycerol.

[0093] At 25°C, 2.44 g of dimethylaminochloroethane and 5 g of water were mixed to prepare a modifier solution. 25.65 g of bisphenol A decaglycerol, 1.29 g of sodium hydroxide and 10 g of ethanol were added to the reactor. After stirring the mixture evenly, the temperature was raised to 60°C and the modifier solution was added. The reaction was carried out for 4 hours. Ethanol and water were removed by vacuum distillation to obtain a crude product. The crude product was placed in a dialysis bag with a molecular weight cutoff of 500 Da and dialyzed in deionized water for 48 hours to obtain dialysate. Water was removed by vacuum distillation and the solution was dried under vacuum at 60°C for 2 hours to obtain 28.09 g of water-based emulsifier.

[0094] At 25°C, water was added to the prepared aqueous emulsifier to dilute the mixture to a solid content of 20%. Then, 0.67g of dioctyl adipate and 0.17g of 4-hydroxybenzenesulfonic acid were added. The mixture was then prepared into an emulsion using a high-speed homogenizing dispersant to obtain 144.65g of bisphenol A decaglycerol sizing agent.

[0095] The bisphenol A decaglycerol-polyurethane sizing agent prepared in this embodiment was diluted to 2% and used for sizing carbon fibers on a carbon fiber production line. The fibers were then dried at 120°C and wound up. The sizing adhesion of the carbon fibers after sizing was 3.5%, the saturated water absorption rate was 0.25%, and the ILSS was 55 MPa.

Claims

1. A method for preparing modified polyurethane, comprising the following steps: Step a) Reaction of polyglycerol and bisphenol A yields a bisphenol A polyglycerol copolymer, wherein the polyglycerol is at least one of diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol, octaglycerol, nonaglycerol, and decaglycerol, and the molar ratio of the polyglycerol to bisphenol A is (0.5~3):1; Step b) Modify the bisphenol A polyglycerol copolymer with a modifier to obtain an aqueous emulsifier. The modifier is at least one of dimethylaminochloroethane, 3-(dimethylamino)chloropropane, and diethylaminochloroethane. The molar ratio of the modifier to the bisphenol A polyglycerol copolymer is (0.2~3):

1. Step c) The modified polyurethane is obtained by reacting the aqueous emulsifier, toluene diisocyanate, polyether and end-capped polyether, wherein the molar ratio of polyether, end-capped polyether, toluene diisocyanate and aqueous emulsifier is (0.1~5):(0.1~5):(0.1~4):

1.

2. The preparation method according to claim 1, characterized in that... In step a): The reaction temperature is 80~120℃, and the reaction time is 12~36 hours.

3. The preparation method according to claim 1, characterized in that: The molar ratio of polyglycerol to bisphenol A is (1~2):

1.

4. The preparation method according to claim 1, characterized in that... Step a) includes: Polyglycerol, bisphenol A, potassium carbonate and solvent are mixed and reacted, and then dried to obtain bisphenol A polyglycerol copolymer.

5. The preparation method according to claim 4, characterized in that: The solvent is diethyl carbonate.

6. The preparation method according to claim 1, characterized in that... In step b): The temperature of the modification reaction is 40~80℃, and the reaction time is 2~6 hours.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the modifier to the bisphenol A polyglycerol copolymer is (0.5~2):

1.

8. The preparation method according to claim 1, characterized in that... Step b) includes: Bisphenol A polyglycerol copolymer, sodium hydroxide and ethanol were mixed, a modifier solution was added, a modification reaction was carried out, and the aqueous emulsifier was obtained by separation and drying.

9. The preparation method according to claim 1, characterized in that... In step c): The polyether is polypropylene glycol, and the molecular weight of the polyether is 200-2000; The end-capping polyether is at least one of polypropylene glycol monomethyl ether, polypropylene glycol monoethyl ether, polypropylene glycol mono-n-propyl ether, and polypropylene glycol monobutyl ether, and the molecular weight of the end-capping polyether is 200 to 2000.

10. The preparation method according to claim 1, characterized in that: The molar ratio of the polyether, the end-capped polyether, the toluene diisocyanate and the aqueous emulsifier is (0.2~2):(0.2~2):(0.4~2):

1.

11. The preparation method according to claim 1, characterized in that... Step c) includes: At 30~50℃, first mix the aqueous emulsifier with polyether and end-capped polyether, add toluene diisocyanate, react for 1~3 hours, then raise the temperature to 70~90℃ and continue the reaction for 4~24 hours.

12. The modified polyurethane obtained by the preparation method according to any one of claims 1 to 11.

13. A bisphenol A polyglycerol-polyurethane sizing agent, comprising modified polyurethane obtained by any one of the preparation methods described in claims 1 to 11, a plasticizer, a curing agent, and water; in, The plasticizer is at least one of dioctyl adipate, dioctyl phthalate, diisononyl phthalate, and dioctyl sebacate; the curing agent is at least one of 4-hydroxybenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, and 2-hydroxybenzenesulfonic acid.

14. A method for preparing the sizing agent according to claim 13, comprising mixing modified polyurethane, plasticizer, curing agent and water, and homogenizing and dispersing them to form an emulsion.

15. The preparation method according to claim 14, characterized in that: The molar ratio of plasticizer, curing agent and modified polyurethane is (0.02~2):(0.01~1):1; The solid content of the sizing agent is 10~50wt%.

16. The preparation method according to claim 15, characterized in that: The molar ratio of plasticizer, curing agent and modified polyurethane is (0.05~1):(0.02~0.5):1.

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