Polyurethane urea and preparation method and application thereof

Abstract

The present invention discloses a polyurethane urea and a preparation method and application thereof. The preparation method comprises the following steps: (1) reacting isocyanate, polyester polyol and phosphorus-containing reactive flame retardant in a solvent under catalyst conditions to obtain an NCO-terminated prepolymer; (2) adding a moisture-curing functional monomer and a chain extender to the prepolymer for reaction to obtain a polyurethane urea after the reaction; wherein the moisture-curing functional monomer comprises at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)ethyl]ethylenediamine or N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine. The method of the present invention obtains a single-component polyurethane urea material having excellent intrinsic flame retardancy and moisture curing properties by introducing a phosphorus-containing reactive flame retardant and a moisture-curing functional monomer.

Description

Technical Field

[0001] The present invention relates to the field of polyurethane urea, and in particular to polyurethane urea and a preparation method and application thereof. Background Art

[0002] Polyurethane urea is an important type of chemical material, especially widely used in coatings, adhesives, sealants and elastomers. The wide application of polyurethane urea is due to its excellent ability to adjust the mechanical properties, which is closely related to the thermodynamic incompatibility of the soft and hard segments in polyurethane urea and the microphase separation structure formed by the movement of molecular chain segments.

[0003] Generally, polyurethane urea needs to be cross-linked and cured before actual use, and its mechanical strength, thermal stability and solubility resistance are improved by forming covalent bonds between polymer chains. At present, polyurethane urea is usually cured using a two-component cross-linking system, which has the advantages of fast curing speed, high mechanical properties, and good heat resistance, but also has the disadvantages of complex construction process, short operating time, and the need for special equipment. Single-component polyurethane urea can also achieve cross-linking, and has the advantages of simple construction and long operating time. At present, single-component polyurethane urea is mainly prepared by reacting stoichiometric excess isocyanate with polyether or polyester polyol, wherein the excess isocyanate group can react chemically with moisture in the atmosphere to form a cross-linked network structure. However, a large amount of carbon dioxide will inevitably be produced during the curing process, resulting in bubbles in the material, thereby reducing its overall performance.

[0004] Like many polymer materials, polyurethane urea is a highly flammable material. When a fire occurs, it will produce violent flames and a large amount of smoke, posing a serious threat to people's lives and property. Therefore, improving the flame retardant properties of polyurethane urea has become an important direction for its functional modification. The commonly used flame retardant modification method is to add flame retardants to polyurethane urea by physical mixing to give it a certain flame retardant effect. However, this method has problems such as poor compatibility, poor dispersibility and poor interface between the flame retardant and the polyurethane urea matrix, and the flame retardant is prone to volatilization and migration, which affects the stability of the material and greatly limits the scope of use of polyurethane urea. Summary of the invention

[0005] The present invention is based on the inventor's discovery and understanding of the following facts and problems: Polyurethane urea is cured by a two-component cross-linking system, which has the disadvantages of complex construction process, short operating time, and the need for special equipment. Single-component polyurethane urea cross-linking will inevitably produce a large amount of carbon dioxide during the curing process, resulting in bubbles in the material and reducing the overall performance. The flame retardant modification method of adding flame retardants to polyurethane urea by physical mixing has the problems of poor compatibility, poor dispersibility and poor interface between the flame retardant and the polyurethane urea matrix, and the flame retardant is prone to volatilization and migration, affecting the stability of the material.

[0006] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiments of the present invention provide a polyurethane urea and a preparation method and application thereof, wherein a single-component polyurethane urea material having excellent intrinsic flame retardancy and moisture curing properties is obtained by introducing a phosphorus-containing reactive flame retardant and a moisture curing functional monomer.

[0007] The embodiment of the present invention provides a method for preparing polyurethane urea, comprising the following steps:

[0008] (1) reacting isocyanate, polyester polyol and phosphorus-containing reactive flame retardant in a solvent under catalyst conditions to obtain an NCO-terminated prepolymer;

[0009] (2) adding a moisture-curable functional monomer and a chain extender to the prepolymer for reaction to obtain a polyurethane urea; wherein the moisture-curable functional monomer comprises at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)ethyl]ethylenediamine or N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine.

[0010] Advantages and technical effects of the preparation method of polyurethane urea of ​​the embodiment of the present invention: the phosphorus-containing reactive flame retardant is firmly inserted into the polyurethane macromolecular skeleton by covalent bonds rather than simple physical blending, and the flame retardant effect is long-lasting, and there is no problem of easy volatility, migration, precipitation, etc.; the phosphorus-containing reactive flame retardant is halogen-free and environmentally friendly, and decomposes at high temperature to produce substances such as phosphorus oxyacid, which can react with hydrogen and free radicals in the combustion products, and has high efficiency and flame retardant, and significantly increases the residual carbon content. The siloxane group in the introduced moisture-curing functional monomer can undergo a hydrolysis reaction under the condition of water vapor to generate silanol, and then quickly undergo a condensation reaction to form a stable Si-O-Si bond, which can effectively improve the solvent resistance and physical and mechanical properties of the material. By introducing a phosphorus-containing reactive flame retardant and a moisture-curing functional monomer, the moisture cross-linking curing and intrinsic flame retardant modification of the single-component polyurethane urea are realized, and a single-component polyurethane urea material with excellent intrinsic flame retardant properties and moisture curing characteristics is obtained. Compared with a two-component curing system, the material is simple to construct and suitable for complex structure construction.

[0011] In some embodiments, in step (1), the isocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate;

[0012] and / or, the polyester polyol comprises at least one of polycaprolactone diol, polyethylene adipate diol, polydiethylene adipate diol or polycarbonate diol;

[0013] and / or, the molecular weight of the polyester polyol is 400-5000;

[0014] And / or, the phosphorus-containing reactive flame retardant includes at least one of N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid dimethyl ester or 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide;

[0015] and / or, the catalyst comprises at least one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate or di[2-(N,N-dimethylaminoethyl)]ether;

[0016] And / or, the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, propylene glycol methyl ether acetate or chloroform.

[0017] In some embodiments, in step (1), the molar ratio of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant is 6.2-9.0:1.0-5.0:1.0-5.0;

[0018] And / or, the added amount of the catalyst is 0.01%-2% of the total mass of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant.

[0019] In some embodiments, in step (1), the reaction temperature is 30-80°C;

[0020] And / or, the reaction time is 0.5 to 10 hours;

[0021] And / or, the reaction is carried out under a nitrogen atmosphere.

[0022] In some embodiments, in step (2), the chain extender includes at least one of N-ethylethylenediamine, N-methyldiethanolamine or N-tert-butyldiethanolamine.

[0023] In some embodiments, in step (2), the total molar amount of the moisture-curable functional monomer and the chain extender is 45%-60% of the NCO molar content in the prepolymer.

[0024] In some embodiments, in step (2), the molar ratio of the moisture-curable functional monomer to the chain extender is 0.1-1.0:0.1-1.0.

[0025] In some embodiments, in step (2), the reaction temperature is 40-100°C;

[0026] And / or, the reaction time is 1 to 10 hours;

[0027] And / or, the reaction is carried out under a nitrogen atmosphere.

[0028] The embodiment of the present invention provides a polyurethane urea, which is prepared by the preparation method described in the embodiment of the present invention. In the embodiment of the present invention, the polyurethane urea is a single-component polyurethane urea material, which has excellent intrinsic flame retardant properties and moisture curing properties.

[0029] The embodiment of the present invention provides an application of polyurethane urea for automobiles, ships, buildings or furniture; and / or for coatings or adhesives. The embodiment of the present invention has all the advantages of moisture-curing flame-retardant single-component polyurethane urea, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a picture of the sample of Example 1 after being immersed for 48 hours.

[0031] Figure 2 It is the infrared spectrum of Example 1.

[0032] Figure 3 This is a picture of Example 1 after the cone calorimeter combustion test.

[0033] Figure 4 This is a picture of comparative example 1 after the cone calorimeter combustion test. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] A method for preparing polyurethane urea according to an embodiment of the present invention comprises the following steps:

[0036] (1) reacting isocyanate, polyester polyol and phosphorus-containing reactive flame retardant in a solvent under catalyst conditions to obtain an NCO-terminated prepolymer;

[0037] (2) adding a moisture-curable functional monomer and a chain extender to the prepolymer for reaction to obtain a polyurethane urea; wherein the moisture-curable functional monomer comprises at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)ethyl]ethylenediamine or N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine.

[0038] In the polyurethane urea of ​​the embodiment of the present invention, the phosphorus-containing reactive flame retardant is firmly inserted into the polyurethane macromolecular skeleton by covalent bonds rather than simple physical blending, and the flame retardant effect is long-lasting, and there are no problems such as easy volatility, migration, and precipitation; the phosphorus-containing reactive flame retardant is halogen-free and environmentally friendly, and decomposes at high temperature to produce substances such as phosphorus oxyacid, which can react with hydrogen and free radicals in the combustion products, and has high efficiency and flame retardant, and significantly increases the residual carbon content. The siloxane group in the introduced moisture-curing functional monomer can undergo a hydrolysis reaction under the condition of water vapor to generate silanol, and then quickly undergo a condensation reaction to form a stable Si-O-Si bond, which can effectively improve the solvent resistance and physical and mechanical properties of the material. By introducing a phosphorus-containing reactive flame retardant and a moisture-curing functional monomer, the moisture cross-linking curing and intrinsic flame retardant modification of the single-component polyurethane urea are achieved, and a single-component polyurethane urea material with excellent intrinsic flame retardant properties and moisture curing characteristics is obtained. Compared with a two-component curing system, the material is simple to construct and is suitable for complex structure construction.

[0039] In some embodiments, in step (1), the isocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate. Preferably, the isocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate.

[0040] In some embodiments, in step (1), the polyester polyol includes at least one of polycaprolactone diol, polyethylene adipate diol, polyethylene adipate diol or polycarbonate diol, preferably, the polyester polyol includes at least one of polycaprolactone diol, polyethylene adipate diol and polyethylene adipate diol; and / or the molecular weight of the polyester polyol is 400-5000, specifically, for example, 400, 500, 530, 1000, 2000, 3000, 4000, 5000. In the embodiment of the present invention, the type of polyester polyol is preferred, which is conducive to improving the reaction efficiency.

[0041] In some embodiments, in step (1), the phosphorus-containing reactive flame retardant includes at least one of N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid dimethyl ester or 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide. Preferably, the phosphorus-containing reactive flame retardant includes at least one of N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester and N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid dimethyl ester. In the embodiments of the present invention, the type of phosphorus-containing reactive flame retardant is preferably selected, which can improve the mobility of molecular chain segments and is conducive to further improving the reaction and flame retardant efficiency.

[0042] In some embodiments, in step (1), the catalyst includes at least one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate or di[2-(N,N-dimethylaminoethyl)]ether. Preferably, the catalyst includes at least one of stannous octoate, dibutyltin dilaurate and dibutyltin diacetate.

[0043] In some embodiments, in step (1), the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, propylene glycol methyl ether acetate or chloroform. Preferably, the solvent includes at least one of N,N-dimethylformamide and N,N-dimethylacetamide.

[0044] In some embodiments, in step (1), the molar ratio of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant is 6.2~9.0:1.0~5.0:1.0~5.0, preferably, 7.0~8.5:1.0~4.0:2.5~5.0. In the embodiment of the present invention, the molar ratio of isocyanate, polyester polyol and phosphorus-containing reactive flame retardant is preferably selected, which can control the phosphate content at a reasonable level, which is conducive to ensuring the flame retardant effect. When the amount of phosphorus-containing reactive flame retardant is too low, the flame retardant efficiency is reduced.

[0045] In some embodiments, in step (1), the amount of the catalyst added is 0.01%-2%, preferably 0.05%-0.2%, of the total mass of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant.

[0046] In some embodiments, in step (1), the reaction temperature is 30-80°C, specifically, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, preferably, 50-80°C; and / or, the reaction time is 0.5-10h, specifically, for example, 0.5h, 1h, 2h, 4h, 6h, 8h, 10h, preferably, 2-4h; and / or, the reaction is carried out under a nitrogen atmosphere. In the embodiments of the present invention, the reaction conditions are optimized to improve the reaction efficiency.

[0047] In some embodiments, in step (1), isocyanate dissolved in a solvent is mixed with polyester polyol and phosphorus-containing reactive flame retardant dissolved in a solvent, and then a catalyst is added to react to obtain an NCO-terminated prepolymer.

[0048] In some embodiments, in step (2), the moisture-curable functional monomer includes at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)ethyl]ethylenediamine or N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine; preferably, the moisture-curable functional monomer includes at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine or N-[3-(trimethoxysilyl)ethyl]ethylenediamine. In the embodiment of the present invention, the moisture-curable functional monomer can introduce siloxane side groups into the macromolecular chain, which is beneficial to the curing and crosslinking of polyurethaneurea.

[0049] In some embodiments, in step (2), the chain extender includes at least one of N-ethylethylenediamine, N-methyldiethanolamine or N-tert-butyldiethanolamine, preferably, the chain extender includes at least one of N-ethylethylenediamine and N-methyldiethanolamine. In the embodiment of the present invention, the chain extender can participate in the formation reaction of the polyurethane urea macromolecular chain, which is beneficial to adjust its molecular structure and material properties.

[0050] In some embodiments, in step (2), the molar ratio of the moisture-curable functional monomer to the chain extender is 0.1-1.0:0.1-1.0, specifically, for example, 0.1:0.1, 0.1:0.2, 0.1:0.5, 0.1:0.8, 0.1:1.0, 1.0:0.1, 0.8:0.1, 0.5:0.1, 0.2:0.1, preferably, 0.2-0.8:0.2-0.8. In the embodiment of the present invention, by optimizing the molar ratio of the moisture-curable functional monomer to the chain extender, it is beneficial to further adjust the molecular structure and material properties of the polyurethane urea, and further improve the intrinsic flame retardant properties and moisture curing properties.

[0051] In some embodiments, in step (2), the total molar amount of the moisture-curable functional monomer and the chain extender is 45% to 60% of the NCO molar content in the prepolymer, specifically, for example, 45%, 47.5%, 50%, 52.5%, 55%, 57.5%, 60%, preferably, 47.5% to 57.5%. In the embodiment of the present invention, the total molar amount of the moisture-curable functional monomer and the chain extender is preferably selected, which is beneficial to further improve the intrinsic flame retardant properties and moisture curing characteristics of polyurethane urea, and is also beneficial to the formation reaction of the polyurethane urea macromolecular chain and improves the reaction efficiency.

[0052] In some embodiments, in step (2), the reaction temperature is 40-100°C, preferably 60-90°C; and / or the reaction time is 1-10 hours, preferably 2-7 hours; and / or the reaction is carried out under a nitrogen atmosphere. In the embodiments of the present invention, the reaction conditions are optimized to facilitate the formation of polyurethane urea macromolecular chains and improve the reaction efficiency.

[0053] A polyurethane urea in an embodiment of the present invention is prepared by the preparation method described in the embodiment of the present invention. In the embodiment of the present invention, the polyurethane urea is a single-component polyurethane urea material, which has excellent intrinsic flame retardancy and moisture curing properties.

[0054] In some embodiments, the polyurethane urea is placed in air to obtain a cured polyurethane urea.

[0055] The polyurethane urea of ​​the embodiment of the present invention is used in automobiles, ships, buildings or furniture; and / or in coatings or adhesives. Preferably, the coating is at least one of a flame retardant coating, an anticorrosive coating and a wear-resistant coating. In the embodiment of the present invention, all the advantages of the moisture-curing flame retardant single-component polyurethane urea are possessed, which will not be described in detail here.

[0056] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0057] Example 1

[0058] A method for preparing a moisture-curable one-component intrinsically flame-retardant polyurethane urea comprises the following steps:

[0059] (1) In a 500 mL dry three-necked flask equipped with a thermometer and a dropping funnel, 10 g (40 mmol) of 4, 4'-diphenylmethane diisocyanate and 160 mL of N, N-dimethylformamide were added under a nitrogen atmosphere. After stirring to dissolve, a mixture of 5.3 g (10 mmol) of polycaprolactone diol (molecular weight 530) and 5.1 g (20 mmol) of N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester dissolved in 80 mL of N, N-dimethylformamide was slowly added dropwise at a dropping rate of 1-2 s / drop. Then, 0.02 g of stannous octoate catalyst was added, the temperature was slowly raised to 70°C, and the reaction was stopped after keeping the temperature for 3 hours to obtain an NCO-terminated prepolymer.

[0060] (2) After the prepolymer obtained in (1) has cooled to room temperature, 0.67 g of N-[3-(trimethoxysilyl)propyl]ethylenediamine (3 mmol) and 0.62 g of N-ethylethylenediamine (7 mmol) are added dropwise, and the temperature is slowly raised to 90°C. After keeping the temperature for 2 hours, the reaction is stopped to obtain the product.

[0061] Example 2

[0062] A method for preparing a moisture-curable one-component intrinsically flame-retardant polyurethane urea comprises the following steps:

[0063] (1) In a 500 mL dry three-necked flask equipped with a thermometer and a dropping funnel, under a nitrogen atmosphere, add 5 g (20 mmol) of 2, 4'-diphenylmethane diisocyanate, 5 g (20 mmol) of 2, 2'-diphenylmethane diisocyanate and 160 mL of N, N-dimethylacetamide. After stirring to dissolve, slowly dropwise add 2.65 g (5 mmol) of polycaprolactone diol (molecular weight 530), 10 g (5 mmol) of polyethylene adipate diol (molecular weight 2000) and 4.54 g (20 mmol) of N, N-dimethylacetamide dissolved in 80 mL of N, N-dimethylacetamide. The mixture of dimethyl N-bis(2-hydroxyethyl)aminomethylenephosphonate was added at a drop rate of 1-2s / drop, and then 0.02g of stannous octoate and 0.03g of dibutyltin dilaurate as catalyst were added, the temperature was slowly raised to 50°C, and the reaction was stopped after keeping warm for 4 hours to obtain an NCO-terminated prepolymer.

[0064] (2) After the prepolymer obtained in (1) has cooled to room temperature, 1.46 g of N-[3-(trimethoxysilyl)ethyl]ethylenediamine (7 mmol) and 0.36 g of N-methyldiethanolamine (3 mmol) are added dropwise, and the temperature is slowly raised to 60°C. After keeping the temperature for 7 hours, the reaction is stopped to obtain the product.

[0065] Example 3

[0066] A method for preparing a moisture-curable one-component intrinsically flame-retardant polyurethane urea comprises the following steps:

[0067] (1) In a 500 mL dry three-necked flask equipped with a thermometer and a dropping funnel, under a nitrogen atmosphere, add 5 g (20 mmol) of 2, 4'-diphenylmethane diisocyanate, 2.61 g (15 mmol) of toluene-2,4-diisocyanate and 160 mL of N, N-dimethylacetamide. After stirring to dissolve, slowly drop 5 g (5 mmol) of polyethylene adipate diol (molecular weight 1000), 3 g (1 mmol) of polyethylene adipate diol (molecular weight 3000), 1.06 g (2 mmol) of polycaprolactone diol (molecular weight 530), 2.55 g (10 mmol) of N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester and 1.14 g (5 mmol) of N, N-dimethylacetamide dissolved in 80 mL of N, N-dimethylacetamide. The mixture of dimethyl N-bis(2-hydroxyethyl)aminomethylenephosphonate was added at a drop rate of 1-2s / drop, and then 0.03g of dibutyltin diacetate catalyst was added, the temperature was slowly raised to 60°C, and the reaction was stopped after keeping warm for 3.5 hours to obtain an NCO-terminated prepolymer.

[0068] (2) After the prepolymer obtained in (1) has cooled to room temperature, a mixture of 0.62 g of N-[3-(trimethoxysilyl)ethyl]ethylenediamine (3 mmol) and 0.67 g of N-[3-(trimethoxysilyl)propyl]ethylenediamine (3 mmol) and a mixture of 0.18 g of N-ethylethylenediamine (2 mmol) and 0.42 g of N-methyldiethanolamine (3.5 mmol) are added dropwise successively, and the temperature is slowly raised to 90°C. After keeping the temperature for 2 hours, the reaction is stopped to obtain the product.

[0069] Example 4

[0070] A method for preparing a moisture-curable one-component intrinsically flame-retardant polyurethane urea comprises the following steps:

[0071] (1) In a 500 mL dry three-necked flask equipped with a thermometer and a dropping funnel, under a nitrogen atmosphere, add 2.5 g (10 mmol) of 2, 2'-diphenylmethane diisocyanate, 2.75 g (11 mmol) of 2, 4'-diphenylmethane diisocyanate, 2.61 g (15 mmol) of toluene-2,6-diisocyanate and 160 mL of N, N-dimethylacetamide. After stirring to dissolve, slowly dropwise add 7 g (7 mmol) of polyethylene adipate diol (molecular weight 1000), 4.24 g (8 mmol) of polycaprolactone diol (molecular weight 530), 2.72 g (12 mmol) of N, N-dimethylacetamide dissolved in 80 mL of N, N-dimethylacetamide. The mixture of dimethyl N-bis(2-hydroxyethyl)aminomethylenephosphonate was added at a drop rate of 1-2s / drop, and then 0.015g of dibutyltin dilaurate catalyst was added, the temperature was slowly raised to 80°C, and the reaction was stopped after keeping the temperature for 2 hours to obtain an NCO-terminated prepolymer.

[0072] (2) After the prepolymer obtained in (1) has cooled to room temperature, a mixture of 0.62 g of N-[3-(trimethoxysilyl)ethyl]ethylenediamine (3 mmol) and 1.11 g of N-[3-(trimethoxysilyl)propyl]ethylenediamine (5 mmol) and 0.24 g of N-methyldiethanolamine (2 mmol) are added dropwise, and the temperature is slowly raised to 70°C. After keeping the temperature for 5 hours, the reaction is stopped to obtain the product.

[0073] Example 5

[0074] A method for preparing a moisture-curable one-component intrinsically flame-retardant polyurethane urea comprises the following steps:

[0075] (1) In a 500 mL dry three-necked flask equipped with a thermometer and a dropping funnel, under a nitrogen atmosphere, add 7.13 g (41 mmol) of toluene-2,6-diisocyanate, 60 mL of N, N-dimethylformamide and 100 mL of N, N-dimethylacetamide. After stirring to dissolve, slowly dropwise add 10 g (2 mmol) of polyethylene adipate diol (molecular weight 5000), 6 g (3 mmol) of polycaprolactone diol (molecular weight 2000), 2.72 g (12 mmol) of N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid dimethyl ester and 3.32 g (13 mmol) of N, N-dimethylacetamide dissolved in 80 mL of N, N-dimethylacetamide. The mixture of diethyl N-bis(2-hydroxyethyl)aminomethylenephosphonate was added at a drop rate of 1-2s / drop, and then 0.01g of stannous octoate and 0.01g of dibutyltin diacetate as catalyst were added, the temperature was slowly raised to 70°C, and the reaction was stopped after keeping warm for 3 hours to obtain an NCO-terminated prepolymer.

[0076] (2) After the prepolymer obtained in (1) has cooled to room temperature, 0.62 g of N-[3-(trimethoxysilyl)ethyl]ethylenediamine (3 mmol) and 0.70 g of N-ethylethylenediamine (8 mmol) are added dropwise, and the temperature is slowly raised to 80°C. After keeping the temperature for 3 hours, the reaction is stopped to obtain the product.

[0077] Comparative Example 1

[0078] The preparation method is the same as that of Example 1, except that in step (1), 5.1 g (20 mmol) of the reactive flame retardant N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester is replaced by 10.6 g (20 mmol) of polycaprolactone diol (molecular weight 530).

[0079] Comparative Example 2

[0080] The preparation method is the same as that of Example 1, except that in step (2), 0.67 g of N-[3-(trimethoxysilyl)propyl]ethylenediamine (3 mmol) and 0.62 g of N-ethylethylenediamine (7 mmol) are replaced by 1.06 g of diethylene glycol (10 mmol).

[0081] Comparative Example 3

[0082] The preparation method is the same as that of Example 1, except that in step (1), 5.1 g (20 mmol) of the reactive flame retardant N, N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester is replaced by 10.6 g (20 mmol) of polycaprolactone diol (molecular weight 530);

[0083] In the step (2), 0.67 g of N-[3-(trimethoxysilyl)propyl]ethylenediamine (3 mmol) and 0.62 g of N-ethylethylenediamine (7 mmol) were replaced with 1.06 g of diethylene glycol (10 mmol).

[0084] The products obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were poured onto a plate and placed at 50° C. for 72 hours. The polyurethane urea after placement was tested. The results are shown in Table 1:

[0085] (1) The reference standard for the Limiting Oxygen Index (LOI) test is: GB / T2406.2 Plastics - Determination of combustion behavior by oxygen index method - Room temperature test.

[0086] (2) The reference standard for cone calorimeter combustion test is: ISO 5660-1:2015.

[0087] (3) The reference standard for tensile properties test is: GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0088] (4) The gel content test method is as follows: weigh 30-50 mg of the polyurethane urea after standing and place it in 50 ml of N, N-dimethylformamide solvent. After 48 hours, the ratio of the mass of the insoluble sample after drying to the mass of the initial sample is the gel content. Repeat the measurement three times for each sample and take the average value.

[0089] Table 1

[0090]

[0091] The polyurethane urea sample (PUUS1) after being placed in Example 1 did not dissolve in N, N-dimethylformamide solvent for 48 hours, and its gel content was tested to be 50±5%. Figure 1 The infrared spectrum of PUUS1 of Example 1 is shown in Figure 2 As shown in the infrared spectrum, the Si-O-Si characteristic absorption peak 1095 cm-1 formed by the hydrolysis and polycondensation of siloxane groups appears. -1 . Figure 1 and Figure 2 It proves that the prepared polyurethane urea is successfully cured.

[0092] The pictures of Example 1 and Comparative Example 1 after the cone calorimeter combustion test are as follows: Figure 3 and Figure 4 As shown, the residual carbon content of comparative example 1 is only 17.0%, while the residual carbon content of embodiment 1 reaches 46.2%, which is 270% of comparative example 1. The oxygen index of embodiment 1 reaches 29.0%, which proves that the polyurethane urea of ​​embodiment 1 has excellent intrinsic flame retardancy.

[0093] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0094] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A method for preparing polyurethane urea, characterized in that: The following steps are involved: (1) reacting an isocyanate, a polyester polyol and a phosphorus-containing reactive flame retardant in a solvent under a catalyst condition to obtain an NCO-terminated prepolymer; the phosphorus-containing reactive flame retardant comprises at least one of N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid dimethyl ester or 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; (2) Adding a moisture-curable functional monomer and a chain extender to the prepolymer for reaction to obtain a polyurethane urea; wherein the moisture-curable functional monomer includes at least one of N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)ethyl]ethylenediamine or N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine; and the chain extender includes at least one of N-ethylethylenediamine, N-methyldiethanolamine or N-tert-butyldiethanolamine.

2. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (1), the isocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate; and / or, the polyester polyol comprises at least one of polycaprolactone diol, polyethylene adipate diol, polydiethylene adipate diol or polycarbonate diol; and / or, the molecular weight of the polyester polyol is 400-5000; and / or, the catalyst comprises at least one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate or di[2-(N,N-dimethylaminoethyl)]ether; And / or, the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, propylene glycol methyl ether acetate or chloroform.

3. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (1), the molar ratio of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant is 6.2-9.0:1.0-5.0:1.0-5.0; And / or, the added amount of the catalyst is 0.01%-2% of the total mass of the isocyanate, polyester polyol and phosphorus-containing reactive flame retardant.

4. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (1), the reaction temperature is 30-80°C; And / or, the reaction time is 0.5 to 10 hours; And / or, the reaction is carried out under a nitrogen atmosphere.

5. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (2), the total molar amount of the moisture-curable functional monomer and the chain extender is 45%-60% of the NCO molar content in the prepolymer.

6. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (2), the molar ratio of the moisture-curable functional monomer to the chain extender is 0.1-1.0:0.1-1.

0.

7. The method for preparing polyurethane urea according to claim 1, characterized in that: In the step (2), the reaction temperature is 40-100°C; And / or, the reaction time is 1 to 10 hours; And / or, the reaction is carried out under a nitrogen atmosphere.

8. A polyurethane urea, characterized in that The polyurethane urea is prepared by the preparation method described in any one of claims 1 to 7.

9. Use of the polyurethane urea according to claim 8, characterized in that: for cars, ships, buildings or furniture; and / or, for coatings or adhesives.

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