An acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites and a method for preparing the same

Abstract

The scheme discloses an acrylic modified water-based polyurethane emulsion for fiber reinforced composite materials and a preparation method thereof, which is prepared from the following components in parts by weight: first polyol 10-60 parts, second polyol 1-5 parts, diisocyanate 10-40 parts, catalyst 0.001-0.1 part, small molecule chain extender 1-4 parts, disulfide chain extender 1-4 parts, hydrophilic chain extender 1-6 parts, crosslinking agent 1-6 parts, silane coupling agent 1-10, salt forming agent 1-6 parts, first acrylic monomer 5-14 parts, second acrylic monomer 5-30 parts, third acrylic monomer 5-30 parts, buffer 0.5-2 parts, emulsifier 1-3 parts and free radical initiator 0.1-0.3 part. The acrylic modified water-based polyurethane emulsion has good stability, and is significantly improved in terms of wettability, heat resistance, bonding strength, self-repairing property and the like compared with the water-based polyurethane.

Description

Technical Field

[0001] This invention relates to the field of polymer material preparation technology, and in particular to an acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials and its preparation method. Background Technology

[0002] Polyurethane (PU) is a general term for a class of high molecular weight polymers containing urethane structural units in their molecular chains. Due to its adjustable hardness, low-temperature resistance, wear resistance, and strong adhesion, it is widely used in textiles, leather, construction, automobiles, papermaking, and pharmaceuticals. Waterborne polyurethane (WPU) is a new type of polyurethane that uses water instead of organic solvents as the dispersion medium, offering advantages such as lower toxicity and environmental friendliness compared to traditional polyurethanes. Acrylic resin is a general term for homopolymers and copolymers of acrylate monomers, as well as various copolymers of other ethylene monomers. Due to its excellent UV resistance, acid and alkali resistance, oxidation resistance, film-forming properties, adhesion, water resistance, and heat resistance, it is widely used in rubber, plastics, coatings, and textile finishing industries. Waterborne polyurethane has poor heat resistance, water resistance, and solvent resistance, while acrylic resin exhibits hot-stickiness and cold-brittleness. Therefore, acrylate emulsions and waterborne polyurethane complement each other. Combining the two, acrylic-modified waterborne polyurethane can produce acrylic-modified waterborne polyurethane emulsions (WPUA) that combine the advantages of both polyurethane and acrylic acid.

[0003] Fiber-reinforced composites are made by bonding ultra-high molecular weight polyethylene (UHMWPE) fibers or aramid fibers together with resin after they are arranged uniformly and straight. Fiber-reinforced composites are becoming a key material for developing multifunctional composites with high strength, high rigidity, and suitability for use in high-humidity and high-temperature environments. As the main component, the resin must be able to elongate and break along with the fibers to maximize the absorption of impact energy, while also possessing high tensile ductility and flame retardancy. Currently, the main resin matrices include epoxy resins, phenolic resins, vinyl ester resins, polyetheretherketones (PEEK), nylon, olefin resins, thermoplastic polyurethanes, and styrene block copolymers. However, a single resin matrix is ​​difficult to meet the comprehensive performance requirements of fiber-reinforced composites; therefore, developing new resins or modifying conventional resins has become a development trend. Summary of the Invention

[0004] One objective of this solution is to provide an acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials. This acrylic-modified waterborne polyurethane emulsion exhibits good stability and shows significant improvements over waterborne polyurethane in terms of water resistance, heat resistance, bond strength, and self-healing properties.

[0005] The second objective of this solution is to provide a method for preparing an acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials.

[0006] To achieve the above objectives, the following plan is proposed:

[0007] An acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials is prepared from the following components in parts by weight:

[0008] 10-60 parts of the first polyol

[0009] 1-5 parts of the second polyol

[0010] 10-40 parts of diisocyanate

[0011] Catalyst 0.001–0.1 parts,

[0012] 1-4 parts of small molecule chain extender

[0013] 1-4 parts of disulfide bond extender

[0014] 1-6 parts of hydrophilic chain extender

[0015] Crosslinking agent 1-6 parts,

[0016] 1-10 parts of silane coupling agent

[0017] Salt-forming agent 1-6 parts,

[0018] 5-14 parts of the first acrylic monomer

[0019] 5-30 parts of the second acrylic acid monomer

[0020] 5-30 parts of the third acrylic acid monomer

[0021] 0.5 to 2 parts buffer,

[0022] 1-3 parts emulsifier

[0023] 0.1 to 0.3 parts of free radical initiator.

[0024] Preferably, the first polyol comprises one or more of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran glycol; the molecular weight of the first polyol is 1000-2000 g / mol.

[0025] Preferably, the second polyol comprises one or more of polycaprolactone diol, polycarbonate diol, polybutadiene diol, polybutadiene-acrylonitrile copolyol, and polyisoprene diol; the molecular weight of the second polyol is 1000-2000 g / mol.

[0026] Preferably, the diisocyanate includes one or more of isophorone diisocyanate, hexamethylene diisocyanate, lysine diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

[0027] Preferably, the catalyst comprises one or more of dibutyl dilaurate, stannous octanoate, bismuth octanoate, bismuth laurate, bismuth naphthenate, triethylenediamine, and N-alkylmorpholine.

[0028] Preferably, the crosslinking agent includes one or more of castor oil, trimethylolpropane, and triethanolamine.

[0029] Preferably, the small molecule chain extender includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, and neopentyl glycol;

[0030] The hydrophilic chain extender includes one or more of the following: dimethylolpropionic acid, dimethylolbutyric acid, sodium 1,2-propanediol-3-sulfonate, sodium 1,4-butanediol-2-sulfonate, sodium ethylenediaminoethanesulfonate, and sodium N-(2-aminoethyl)-2-aminoethanesulfonate.

[0031] The disulfide chain extender includes one or more of 4,4-diaminodiphenyl sulfide, 3,3-dihydroxydiphenyl disulfide, and 2,2-dithiodiethanol.

[0032] Preferably, the silane coupling agent comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0033] The salt-forming agent includes one or more of triethylamine, tripropylamine, ammonia, diethylenetriamine, and sodium hydroxide;

[0034] The buffer includes one or more of sodium bicarbonate, sodium dihydrogen phosphate, and sodium acetate;

[0035] The emulsifier is one or more of sodium dodecyl sulfate, 2-acrylamide-2-methylpropanesulfonic acid, sodium allyloxyhydroxypropyl sulfonate and sodium di(2-ethylhexyl)phosphate;

[0036] The free radical initiator includes one or more of ammonium persulfate, potassium persulfate, sodium persulfate, and azobisisobutyronitrile.

[0037] Preferably, the first acrylic monomer includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxyoxymethacrylate, and the molecular weight of the first acrylic monomer is 500-1000 g / mol.

[0038] The second acrylic monomer includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate and isooctyl acrylate, and the molecular weight of the second acrylic monomer is 500 to 1000 g / mol.

[0039] The third acrylic monomer includes one or more of methyl methacrylate, vinyl acetate, and styrene, and the molecular weight of the third acrylic monomer is 500-1000 g / mol.

[0040] Secondly, a method for preparing the above-mentioned acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials is provided, the method comprising the following steps:

[0041] The first polyol and the second polyol were mixed and then vacuum dehydrated at 100-130°C for 2-3 hours.

[0042] Add diisocyanate and catalyst, react at 75-90℃ for 1-3 hours, add crosslinking agent, small molecule chain extender, disulfide bond chain extender, hydrophilic chain extender, silane coupling agent, and first acrylic monomer, react at 75-90℃ for 3-5 hours to prepare waterborne polyurethane prepolymer; during the reaction, add one or more of acetone, butanone, and N-methylpyrrolidone to reduce viscosity.

[0043] Add a salting agent and react at 30-40℃ for 10 min, then adjust the pH to 6-8; emulsify with deionized water at high speed for 10-30 min; remove the solvent by vacuum distillation, add water to adjust the solid content, and obtain an aqueous polyurethane emulsion.

[0044] A portion of the second acrylic monomer, buffer, emulsifier, and a portion of the initiator are added to an aqueous polyurethane emulsion, and the mixture is stirred at low speed at 70–90°C for 3–5 hours. The remaining second acrylic monomer, initiator, and third acrylic monomer are then added, and the mixture is reacted for 5–8 hours to obtain an acrylic-modified aqueous polyurethane emulsion.

[0045] The beneficial effects of this plan are as follows:

[0046] This application improves the water resistance and heat resistance of waterborne polyurethane by modifying it with acrylic acid. Simultaneously, the addition of crosslinking agents and silane coupling agents further enhances the interfacial adhesion strength between the acrylic-modified waterborne polyurethane and UHMWPE fibers and aramid fibers. The introduced disulfide bonds endow the acrylic-modified waterborne polyurethane with certain self-healing properties. Detailed Implementation

[0047] The implementation methods of this solution will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of this solution, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this solution can be combined with each other.

[0048] The terms “first,” “second,” etc. (if applicable) in the specification and claims are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data used in this way can be interchanged where appropriate. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that comprises a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] The inventors of this application provide an acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composite materials, prepared from the following components in parts by weight:

[0050] 10-60 parts of the first polyol

[0051] 1-5 parts of the second polyol

[0052] 10-40 parts of diisocyanate

[0053] Catalyst 0.001–0.1 parts,

[0054] 1-4 parts of small molecule chain extender

[0055] 1-4 parts of disulfide bond extender

[0056] 1-6 parts of hydrophilic chain extender

[0057] Crosslinking agent 1-6 parts,

[0058] 1-10 parts of silane coupling agent

[0059] Salt-forming agent 1-6 parts,

[0060] 5-14 parts of the first acrylic monomer

[0061] 5-30 parts of the second acrylic acid monomer

[0062] 5-30 parts of the third acrylic acid monomer

[0063] 0.5 to 2 parts buffer,

[0064] 1-3 parts emulsifier

[0065] 0.1 to 0.3 parts of free radical initiator.

[0066] In one embodiment, the first polyol comprises one or more of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran glycol; the molecular weight of the first polyol is 1000 to 2000 g / mol.

[0067] In one embodiment, the second polyol comprises one or more of polycaprolactone diol, polycarbonate diol, polybutadiene diol, polybutadiene-acrylonitrile copolyol, and polyisoprene diol; the molecular weight of the second polyol is 1000 to 2000 g / mol.

[0068] In one embodiment, the diisocyanate includes one or more of isophorone diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0069] In one embodiment, the catalyst comprises one or more of dibutyl dilaurate, stannous octanoate, bismuth octanoate, bismuth laurate, bismuth naphthenate, triethylenediamine, and N-alkylmorpholine.

[0070] In one embodiment, the crosslinking agent includes one or more of castor oil, trimethylolpropane, and triethanolamine.

[0071] In one embodiment, the small molecule chain extender includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, and neopentyl glycol.

[0072] In one embodiment, the hydrophilic chain extender comprises one or more of dimethylolpropionic acid, dimethylolbutyric acid, sodium 1,2-propanediol-3-sulfonate, sodium 1,4-butanediol-2-sulfonate, sodium ethylenediaminoethanesulfonate, and sodium N-(2-aminoethyl)-2-aminoethanesulfonate.

[0073] In one embodiment, the disulfide chain extender includes one or more of 4,4-diaminodiphenyl sulfide, 3,3-dihydroxydiphenyl disulfide, and 2,2-dithiodiethanol.

[0074] In one embodiment, the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0075] In one embodiment, the salt-forming agent includes one or more of triethylamine, tripropylamine, ammonia, diethylenetriamine, and sodium hydroxide.

[0076] In one embodiment, the buffer includes one or more of sodium bicarbonate, sodium dihydrogen phosphate, and sodium acetate.

[0077] In one embodiment, the emulsifier is one or more of sodium dodecyl sulfate, 2-acrylamide-2-methylpropanesulfonic acid, sodium allyloxyhydroxypropyl sulfonate, and sodium di(2-ethylhexyl)phosphate.

[0078] In one embodiment, the free radical initiator includes one or more of ammonium persulfate, potassium persulfate, sodium persulfate, and azobisisobutyronitrile.

[0079] In one embodiment, the first acrylic monomer includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxyoxymethacrylate, and the molecular weight of the first acrylic monomer is 500 to 1000 g / mol.

[0080] In one embodiment, the second acrylic monomer includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate and isooctyl acrylate, and the molecular weight of the second acrylic monomer is 500 to 1000 g / mol.

[0081] In one embodiment, the third acrylic monomer includes one or more of methyl methacrylate, vinyl acetate, and styrene, and the molecular weight of the third acrylic monomer is 500 to 1000 g / mol.

[0082] This application also provides a method for preparing an acrylic-modified waterborne polyurethane emulsion for the above-mentioned fiber-reinforced composite material, the method comprising the following steps:

[0083] The first polyol and the second polyol were mixed and then vacuum dehydrated at 100-130°C for 2-3 hours.

[0084] Add diisocyanate and catalyst, react at 75-90℃ for 1-3 hours, add crosslinking agent, small molecule chain extender, disulfide bond chain extender, hydrophilic chain extender, silane coupling agent, and first acrylic monomer, react at 75-90℃ for 3-5 hours to prepare waterborne polyurethane prepolymer; during the reaction, add one or more of acetone, butanone, and N-methylpyrrolidone to reduce viscosity.

[0085] Add a salt-forming agent to the waterborne polyurethane prepolymer and react at 30-40℃ for 10 min, then adjust the pH to 6-8; emulsify with deionized water at high speed for 10-30 min; remove the solvent by vacuum distillation, add water to adjust the solid content, and obtain the waterborne polyurethane emulsion.

[0086] A portion of the second acrylic monomer, buffer, emulsifier, and a portion of the initiator are added to an aqueous polyurethane emulsion, and the mixture is stirred at low speed at 70–90°C for 3–5 hours. The remaining second acrylic monomer, initiator, and third acrylic monomer are then added, and the mixture is reacted for 5–8 hours to obtain an acrylic-modified aqueous polyurethane (WPUA) emulsion.

[0087] The present application will be described below through specific embodiments.

[0088] Example 1

[0089] Polytetrahydrofuran diol (18 mmol), polycaprolactone diol (1 mmol), polybutadiene-acrylonitrile copolymer diol (1 mmol), hexamethylene diisocyanate (65 mmol), and dibutyltin dilaurate (0.1 mmol) were reacted at 80 °C for 1 h. Then, trimethylolpropane (5 mmol), dimethylolpropionic acid (8 mmol), 2,2-dithiodiethanol (5 mmol), ethylenediamine (4 mmol), γ-aminopropyltriethoxysilane (10 mmol), and hydroxyethyl acrylate (10 mmol) were added, and the mixture was reacted at 80 °C for 4 h to obtain a waterborne polyurethane prepolymer. Polymer; triethylamine (9.5 mmol) was added and reacted for 10 min, followed by high-speed emulsification with deionized water for 20 min, and water was added to adjust the solid content to 35% to obtain an aqueous polyurethane emulsion; methyl acrylate (4 mmol), sodium bicarbonate (1 mmol), 2-acrylamide-2-methylpropanesulfonic acid (2 mmol), and sodium persulfate (0.3 mmol) were added to the aqueous polyurethane emulsion and reacted at 80 °C for 4 h, followed by the addition of methyl acrylate (8 mmol), sodium persulfate (0.6 mmol), and methyl methacrylate (6 mmol), and the reaction was carried out for 5 h to obtain an acrylic acid-modified aqueous polyurethane emulsion.

[0090] Example 2

[0091] Polyethylene glycol (18 mmol), polycarbonate glycol (1 mmol), polybutadiene glycol (1 mmol), isophorone diisocyanate (65 mmol), dibutyltin dilaurate (0.08 mmol), and bismuth laurate (0.02 mmol) were reacted at 80 °C for 1 h. Then, triethanolamine (5 mmol), sodium 1,2-propanediol-3-sulfonate (8 mmol), 3,3-dihydroxydiphenyl disulfide (5 mmol), ethylene glycol (4 mmol), γ-glycidyl etheroxypropyltrimethoxysilane (10 mmol), and hydroxypropyl acrylate (10 mmol) were added and reacted at 80 °C. A waterborne polyurethane prepolymer was obtained by reacting for 4 hours. Diethylenetriamine (9.5 mmol) was added and reacted for 10 minutes. Deionized water was added and emulsified at high speed for 20 minutes. Water was added to adjust the solid content to 35% to obtain a waterborne polyurethane emulsion. Ethyl acrylate (4 mmol), sodium dihydrogen phosphate (1 mmol), sodium allyl hydroxypropyl sulfonate (2 mmol), and ammonium persulfate (0.3 mmol) were added to the waterborne polyurethane emulsion and reacted at 80 °C for 4 hours. Methyl acrylate (8 mmol), ammonium persulfate (0.6 mmol), and vinyl acetate (6 mmol) were added and reacted for 5 hours to obtain an acrylic acid-modified waterborne polyurethane emulsion.

[0092] Example 3

[0093] Polypropylene glycol (18 mmol), polycaprolactone glycol (1 mmol), polyisoprene glycol (1 mmol), hexamethylene diisocyanate (65 mmol), stannous octoate (0.08 mmol), and triethylenediamine (0.02 mmol) were reacted at 80 °C for 1 h. Then, triethanolamine (5 mmol), dimethylolbutyric acid (8 mmol), 2,2-dithiodiethanol (5 mmol), neopentyl glycol (4 mmol), γ-(methacryloyloxy)propyltrimethoxysilane (10 mmol), and hydroxyl methacrylate (10 mmol) were added, and the reaction was continued at 80 °C for 4 h. Acetone was added during the reaction to reduce viscosity, yielding an aqueous polypropylene glycol solution. A urethane prepolymer was prepared; tripropylamine (9.5 mmol) was added and reacted for 10 min, followed by high-speed emulsification with deionized water for 20 min, solvent was removed by vacuum distillation, and water was added to adjust the solid content to 35% to obtain an aqueous polyurethane emulsion; isooctyl acrylate (4 mmol), sodium dihydrogen phosphate (1 mmol), sodium di(2-ethylhexyl) phosphate (2 mmol), sodium persulfate (0.2 mmol), and azobisisobutyronitrile (0.1 mmol) were added to the aqueous polyurethane emulsion and reacted at 80 °C for 4 h; isooctyl acrylate (8 mmol), sodium persulfate (0.6 mmol), and methyl methacrylate (6 mmol) were added and reacted for 5 h to obtain an acrylic-modified aqueous polyurethane emulsion.

[0094] Example 4

[0095] Polytetrahydrofuran diol (13 mmol), polypropylene glycol (5 mmol), polycaprolactone diol (1 mmol), polybutadiene-acrylonitrile copolymer (1 mmol), isophorone diisocyanate (40 mmol), hexamethylene diisocyanate (25 mmol), dibutyltin dilaurate (0.08 mmol), and bismuth laurate (0.02 mmol) were reacted at 80 °C for 1 h. Trimethylolpropane (5 mmol), dimethylolpropionic acid (8 mmol), 4,4-diaminodiphenyl sulfide (5 mmol), ethylenediamine (3 mmol), ethylene glycol (1 mmol), γ-aminopropyltriethoxysilane (10 mmol), and hydroxyethyl acrylate (10 mmol) were added, and the mixture was reacted at 80 °C for 4 h. During the reaction, [further details are needed]. Acetone was used to reduce viscosity, resulting in an aqueous polyurethane prepolymer. Triethylamine (9.5 mmol) was added and reacted for 10 min. The solvent was removed by vacuum distillation, and deionized water was added for high-speed emulsification for 20 min. Water was added to adjust the solid content to 35%, resulting in an aqueous polyurethane emulsion. Methyl acrylate (3 mmol), ethyl acrylate (1 mmol), sodium dihydrogen phosphate (1 mmol), sodium allyl hydroxypropyl sulfonate (1 mmol), sodium di(2-ethylhexyl) phosphate (1 mmol), and sodium persulfate (0.3 mmol) were added to the aqueous polyurethane emulsion and reacted at 80 °C for 4 h. Methyl acrylate (8 mmol), sodium persulfate (0.6 mmol), methyl methacrylate (4 mmol), and styrene (2) were added and reacted for 5 h to obtain an acrylic-modified aqueous polyurethane emulsion.

[0096] Comparative Example 1

[0097] Pure waterborne polyurethane

[0098] Polytetrahydrofuran diol (18 mmol), hexamethylene diisocyanate (45 mmol), and dibutyltin dilaurate (0.1 mmol) were reacted at 80 °C for 1 h. Then, dimethylolpropionic acid (15 mmol) and ethylenediamine (5 mmol) were added, and the reaction was continued at 80 °C for 4 h to obtain an aqueous polyurethane prepolymer. Triethylamine (9.5 mmol) was added and reacted for 10 min. Deionized water was added and the mixture was emulsified at high speed for 20 min. Water was added to adjust the solid content to 35%, yielding an aqueous polyurethane emulsion.

[0099] Comparative Example 2

[0100] Acrylic modified waterborne polyurethane

[0101] Polytetrahydrofuran diol (18 mmol), hexamethylene diisocyanate (52 mmol), and dibutyltin dilaurate (0.1 mmol) were reacted at 80 °C for 1 h. Dimethylolpropionic acid (15 mmol), ethylenediamine (5 mmol), and hydroxyethyl acrylate (10 mmol) were added, and the mixture was reacted at 80 °C for 4 h to obtain an aqueous polyurethane prepolymer. Triethylamine (9.5 mmol) was added, and the mixture was reacted for 10 min. Deionized water was added, and the mixture was emulsified at high speed for 20 min. Water was added to adjust the solid content to 35% to obtain an aqueous polyurethane emulsion. Methyl acrylate (12 mmol), sodium bicarbonate (1 mmol), sodium dodecyl sulfate (2 mmol), sodium persulfate (0.9 mmol), and methyl methacrylate (4 mmol) were added to the aqueous polyurethane emulsion, and the mixture was reacted at 80 °C for 7 h to obtain an acrylic acid-modified aqueous polyurethane emulsion.

[0102] The products obtained in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests, and the test results are shown in Table 1.

[0103] Table 1

[0104]

[0105] As can be seen from Table 1, the acrylic modified waterborne polyurethane prepared according to the formulation designed in this invention has better heat resistance, self-healing properties and adhesion to ultra-high molecular weight polyethylene (UHMWPE) fibers by introducing crosslinking agents and silane coupling agents and introducing acrylic monomers with different functions in a stepwise gradient polymerization.

[0106] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. An acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites, characterized by, Prepared from the following components by weight: The first polyol 10-60 parts, The second polyol 1-5 parts, Diisocyanate 10-40 parts, Catalyst 0.001-0.1 parts, Small molecule chain extender 1-4 parts, Disulfide chain extender 1-4 parts, Hydrophilic chain extender 1-6 parts, Crosslinking agent 1-6 parts, Silane coupling agent 1-10 parts, Salting agent 1-6 parts, The first acrylic monomer 5-14 parts, The second acrylic monomer 5-30 parts, The third acrylic monomer 5-30 parts, Buffer 0.5-2 parts, Emulsifier 1-3 parts, Radical initiator 0.1-0.3 parts; The first polyol includes one or more of polyethylene oxide glycol, polypropylene oxide glycol and polytetrahydrofuran diol; the molecular weight of the first polyol is 1000-2000 g / mol; The second polyol includes one or more of polycaprolactone diol, polycarbonate diol, polybutadiene diol, polybutadiene-acrylonitrile copolymer diol and polyisoprene diol; the molecular weight of the second polyol is 1000-2000 g / mol; The disulfide chain extender includes one or more of 4,4-diamino diphenyl sulfide and 3,3-dihydroxy diphenyl disulfide; The crosslinking agent includes one or more of castor oil, trimethylolpropane and triethanolamine; The silane coupling agent includes one or more of γ-aminopropyl triethoxysilane, γ-glycidyl ether propyl trimethoxysilane, γ-(methacryloyloxy) propyl trimethoxysilane and γ-mercaptopropyl trimethoxysilane; The first acrylic monomer includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxy methacrylate, and the molecular weight of the first acrylic monomer is 500-1000 g / mol; The second acrylic monomer includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate and isooctyl acrylate, and the molecular weight of the second acrylic monomer is 500-1000 g / mol; The third acrylic monomer includes one or more of methyl methacrylate, vinyl acetate and styrene, and the molecular weight of the third acrylic monomer is 500-1000 g / mol; The preparation method of the acrylic modified waterborne polyurethane emulsion for fiber reinforced composites comprises the following steps: mixing the first polyol and the second polyol, and then vacuum dehydrating at 100-130℃ for 2-3h; Adding diisocyanate, catalyst, reacting at 75-90℃ for 1-3h, adding crosslinking agent, small molecule chain extender, disulfide chain extender, hydrophilic chain extender, silane coupling agent and the first acrylic monomer, and reacting at 75-90℃ for 3-5h to prepare a waterborne polyurethane prepolymer; one or more of acetone, butanone and N-methyl pyrrolidone is added during the reaction to reduce the viscosity; Adding salting agent to the waterborne polyurethane prepolymer and reacting at 30-40℃ for 10min to adjust the ph to 6-8; high-speed emulsifying with deionized water for 10-30min; removing the solvent by reduced pressure distillation, and adjusting the solid content by adding water to obtain a waterborne polyurethane emulsion; Part of the second acrylic monomer, a buffer, an emulsifier, part of an initiator, is added into the aqueous polyurethane emulsion, and stirred at a low speed at 70-90 DEG C for 3-5 h; the remaining second acrylic monomer and initiator, third acrylic monomer are added, and reacted for 5-8 h to obtain the acrylic modified aqueous polyurethane emulsion.

2. The acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites according to claim 1, characterized by, The diisocyanate includes one or more of isophorone diisocyanate, hexamethylene diisocyanate, lysine diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

3. The acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites according to claim 1, characterized by, The catalyst includes one or more of dibutyl dilaurylate, stannous octoate, bismuth octoate, bismuth laurate, bismuth naphthenate, triethylenediamine and N-alkyl morpholine.

4. The acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites according to claim 1, characterized by, The small molecule chain extender includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, ethylene glycol, propylene glycol, 1,4-butanediol, glycol and neopentyl glycol; The hydrophilic chain extender includes one or more of dimethylolpropionic acid, dimethylolbutyric acid, 1,2-propanediol-3-sulfonic acid sodium, 1,4-butanediol-2-sulfonic acid sodium, ethylenediamine ethanesulfonic acid sodium and N-(2-aminoethyl)-2-aminoethanesulfonic acid sodium salt.

5. The acrylic-modified waterborne polyurethane emulsion for fiber-reinforced composites according to claim 1, characterized by, The salt forming agent includes one or more of triethylamine, tripropylamine, ammonia, diethylenetriamine and sodium hydroxide; The buffer includes one or more of sodium bicarbonate, sodium dihydrogen phosphate and sodium acetate; The emulsifier is one or more of sodium dodecyl sulfate, 2-acrylamide-2-methylpropanesulfonic acid, allyloxyhydroxypropyl sulfonic acid sodium and di(2-ethylhexyl)phosphoric acid sodium; The free radical initiator includes one or more of ammonium persulfate, potassium persulfate, sodium persulfate and azobisisobutyronitrile.

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