Water-based flame-retardant polyurethane resin and preparation method thereof

Abstract

The invention relates to the technical field of waterborne polyurethane resin, in particular to waterborne flame-retardant polyurethane resin and a preparation method thereof. The waterborne flame-retardant polyurethane resin comprises the following raw materials in parts by weight: 120-140 parts of deionized water, 40-60 parts of polyol, 10-20 parts of polyisocyanate, 10-20 parts of a chain extender, 10-20 parts of a flame retardant, 2-4 parts of a catalyst and 2-4 parts of a neutralizer. The flame retardant is composed of a first additive and a second additive, and the mass ratio of the first additive to the second additive is 1: 0.5. According to the invention, after the phytic acid is combined with the aluminum hydroxide, the coating can provide flame-retardant protection for the coating and a covering material in a relatively wide temperature range, and the coating can still provide relatively good flame-retardant protection performance when the coating is not in direct contact with a heat source during combustion, so that the flame-retardant performance of the waterborne flame-retardant polyurethane resin is improved.

Description

Technical Field

[0001] The invention relates to the technical field of waterborne polyurethane resins, in particular to a waterborne flame-retardant polyurethane resin and a preparation method thereof. Background Art

[0002] Waterborne polyurethane resin is a polyurethane system with water as the dispersion medium. Waterborne polyurethane resin is a polymer material with excellent performance and environmental protection characteristics, and is widely used in many fields.

[0003] In the prior art, the components of waterborne polyurethane resin contain a lot of organic matter, which can easily cause the coating and the coating material to burn when burning occurs around the coating, that is, the flame retardant performance is poor. Based on this, the present invention provides a waterborne flame retardant polyurethane resin and a preparation method thereof. Summary of the invention

[0004] The purpose of the present invention is to provide a water-based flame-retardant polyurethane resin and a preparation method thereof. The water-based flame-retardant polyurethane resin prepared by the present invention not only has good flame retardant properties, but also has excellent hardness properties, thereby effectively improving the use performance of the water-based flame-retardant polyurethane resin.

[0005] To achieve the above object, the present invention provides the following technical solution: a water-based flame-retardant polyurethane resin, comprising the following raw materials in parts by weight: 120 to 140 parts of deionized water, 40 to 60 parts of polyol, 10 to 20 parts of polyisocyanate, 10 to 20 parts of chain extender, 10 to 20 parts of flame retardant, 2 to 4 parts of catalyst and 2 to 4 parts of neutralizer; The flame retardant consists of a first additive and a second additive, and the mass ratio of the first additive to the second additive is 1:0.5.

[0006] Furthermore, the first additive is prepared by the following method: adding phytic acid to deionized water, wherein the mass of the phytic acid is 25-35% of the mass of the deionized water, stirring and mixing, adding sodium hydroxide solution, adjusting the pH value to 4-6, adding aluminum hydroxide, wherein the mass of the aluminum hydroxide is 80-90% of the phytic acid, after preliminary mixing, placing on a magnetic stirrer, setting the speed to 500-700 r / min at room temperature, stirring for 20-30 minutes, and fully mixing to obtain the first additive.

[0007] Furthermore, after the first additive is mixed, it is placed in a stirrer and kept in a low-speed stirring state for standby use.

[0008] Further, the second additive is prepared by the following method: The palm wax is crushed and ground to obtain powdered palm wax. The powdered palm wax is mixed with xylene solution, and the mass of the xylene solution is 2.5 times that of the powdered palm wax. After mixing, it is heated in a water bath to 90 °C. After the powdered palm wax melts, it is stirred evenly to obtain the second additive.

[0009] Further, the phytic acid is prepared by the following method: Rice bran is selected as the raw material. The rice bran is mixed with hydrochloric acid solution, and the mass ratio of the rice bran to the hydrochloric acid solution is 1:(4 - 6). It is stirred and mixed for 6 - 10 min. After mixing, it is heated to 40 - 80 °C and kept warm for reaction for 2 - 4 h. Stirring is continuously carried out during the heating and heat preservation processes. Then it is placed in a centrifuge, and the rotation speed is set at 3000 - 4000 r / min for centrifugation for 8 - 12 min. After the centrifugation is completed, the supernatant is collected to obtain phytic acid.

[0010] Further, the aluminum hydroxide selected has a particle size of ≤50 μm.

[0011] Further, the rice bran selected has a particle size of ≤80 μm.

[0012] Further, the flame retardant is prepared by the following method: Weigh the first additive and the second additive as required for preliminary mixing. After preliminary mixing, it is left standing for 15 - 25 min and then put into a mixing equipment for stirring. After stirring evenly, the flame retardant is obtained.

[0013] Further, the stirring speed of the mixing equipment is 1800 - 2200 rpm, and the stirring time is 15 - 25 min.

[0014] Further, a preparation method of a waterborne flame-retardant polyurethane resin includes the following steps: S1: Weigh polyol and flame retardant as required in a four-necked flask. Nitrogen is introduced into the four-necked flask, and then polyisocyanate is added. After heating and reacting, a prepolymer is obtained. The reaction temperature is 80 - 90 °C, and the time is 2 - 4 h; S2: When the prepolymer cools down to 60 °C, a chain extender and a catalyst are added, and they are mixed and reacted for 2 - 4 h. The mixed reaction temperature is 70 - 80 °C. Then the prepolymer is sent into an emulsification kettle, a neutralizing agent is added, and deionized water is added for emulsification treatment under high-speed shearing to obtain an emulsion; S3: The emulsion is poured into a distillation kettle and subjected to vacuum treatment to obtain the waterborne flame-retardant polyurethane resin.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the present invention, after phytic acid combines with aluminum hydroxide, since the thermal decomposition temperature of aluminum hydroxide as a metal material is relatively fixed, while phytic acid as a plant material can undergo thermal decomposition and carbonization processes in a relatively low temperature range. Therefore, after phytic acid combines with aluminum hydroxide, the coating can provide flame retardant protection for the coating and the covering material in a relatively wide temperature range. When the coating does not directly contact the heat source during combustion, the coating can still provide good flame retardant protection performance, improving the flame retardant performance of the waterborne flame retardant polyurethane resin.

[0016] 2. In the present invention, after phytic acid is prepared using rice bran as a raw material, phytic acid has good antioxidant properties. Phytic acid will decompose under high temperature conditions to produce phosphoric acid and polyphosphoric acid with dehydration and carbonization properties, causing a dehydration carbonization reaction on the coating surface and forming a dense carbonaceous protective layer on the coating surface. The generation of the carbonaceous protective layer can isolate oxygen, prevent oxygen from contacting the unburned substances inside, and effectively block the transfer of heat, reducing the heat conduction to the inside, protecting the internal materials of the coating, reducing the possibility and speed of combustion, and thus improving the flame retardant performance of the waterborne polyurethane resin.

[0017] 3. In the present invention, phytic acid and aluminum hydroxide are combined to prepare a waterborne flame retardant polyurethane resin. Using the phosphoric acid group component in phytic acid, the phosphoric acid group has chelating ability, enabling phytic acid to form a stable chelate with aluminum ions in aluminum hydroxide, thereby tightly combining phytic acid and aluminum ions to form a coordination bond. Using the coordination effect between phytic acid and aluminum ions, during combustion, the alumina generated during the thermal decomposition of aluminum ions can combine with the carbon layer after phytic acid is carbonized by heat, better preventing the transfer of heat and oxygen, and improving the flame retardant performance of the waterborne polyurethane resin coating.

[0018] 4. In the present invention, palm wax, as a hard wax with a relatively high flash point, has high hardness and wear resistance. After being added to the preparation of the waterborne polyurethane resin, it can improve the hardness and wear resistance of the coating, making the coating more scratch-resistant and wear-resistant, and improving the service life of the coating. The main component of palm wax is triacontanyl cerotate. After phytic acid combines with triacontanyl cerotate, using the antioxidant property of phytic acid, a synergistic antioxidant reaction can occur, effectively delaying the oxidation process of the waterborne polyurethane resin coating and improving the service life of the coating.

[0019] 5. The raw materials of phytic acid and palm wax are relatively environmentally friendly, which can reduce the environmental pollution caused by the preparation of the waterborne polyurethane resin, meet the environmental protection requirements, facilitate the sustainable use of resources, and reduce the dependence on non-renewable resources. Detailed implementation mode

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application is described clearly and completely.

[0022] The present embodiment provides a water-based flame-retardant polyurethane resin, comprising the following raw materials in parts by weight: 120 to 140 parts of deionized water, 40 to 60 parts of polyol, 10 to 20 parts of polyisocyanate, 10 to 20 parts of chain extender, 10 to 20 parts of flame retardant, 2 to 4 parts of catalyst and 2 to 4 parts of neutralizer; The flame retardant consists of a first additive and a second additive, and the mass ratio of the first additive to the second additive is 1:0.5.

[0023] In some embodiments, the first additive is prepared by the following method: adding phytic acid to deionized water, the mass of phytic acid is 25-35% of the mass of deionized water, stirring and mixing, adding sodium hydroxide solution, adjusting the pH value to 4-6, adding aluminum hydroxide, the mass of aluminum hydroxide is 80-90% of the phytic acid, after preliminary mixing, placing on a magnetic stirrer, setting the speed to 500-700r / min at room temperature, stirring for 20-30min, and after sufficient mixing, obtaining the first additive.

[0024] In this embodiment, phytic acid is combined with aluminum hydroxide to prepare a water-based flame-retardant polyurethane resin. The phosphate group component in phytic acid has a chelating ability, so that phytic acid and aluminum ions in aluminum hydroxide form a stable chelate, so that the phytic acid and aluminum ions are tightly combined to form a coordination bond. Utilizing the coordination effect of phytic acid and aluminum ions, when combustion occurs, the aluminum oxide produced during the thermal decomposition of aluminum ions can be combined with the carbon layer after the phytic acid is carbonized by heat, thereby better preventing the transfer of heat and oxygen and improving the flame retardant properties of the water-based polyurethane resin coating.

[0025] In some embodiments, after the first additive is mixed, it is placed in a stirrer and kept in a low-speed stirring state for use.

[0026] In some embodiments, the second additive is prepared by the following method: crushing and grinding palm wax to obtain powdered palm wax, mixing the powdered palm wax with xylene solution, the mass of the xylene solution being 2.5 times the mass of the powdered palm wax, heating in a water bath to 90°C after mixing, stirring evenly after the powdered palm wax is melted, to obtain the second additive.

[0027] In this embodiment, palm wax, as a hard wax with a relatively high flash point, has high hardness and wear resistance. After being added to the preparation of waterborne polyurethane resin, it can improve the hardness and wear resistance of the coating, making the coating more scratch-resistant and wear-resistant, and enhancing the service life of the coating. The main component of palm wax is triacontanyl cerotate. After phytic acid binds to triacontanyl cerotate, using the antioxidant property of phytic acid, a synergistic antioxidant reaction can occur, effectively delaying the oxidation process of the waterborne polyurethane resin coating and enhancing the service life of the coating.

[0028] In some embodiments, phytic acid is prepared by the following method: Select rice bran as the raw material, mix the rice bran with hydrochloric acid solution, and the mass ratio of rice bran to hydrochloric acid solution is 1:(4 - 6). Stir and mix for 6 - 10 min. After completion of mixing, heat to 40 - 80 °C and hold for reaction for 2 - 4 h. Stir continuously during the heating and holding processes. Then place it in a centrifuge, set the rotation speed at 3000 - 4000 r / min, and centrifuge for 8 - 12 min. After completion of the centrifugation process, collect the supernatant to obtain phytic acid.

[0029] In this embodiment, after using rice bran as the raw material to prepare phytic acid, phytic acid has good antioxidant properties. Phytic acid will decompose under high-temperature conditions to produce phosphoric acid and polyphosphoric acid with dehydration and carbonization properties, causing a dehydration carbonization reaction on the coating surface and forming a dense carbonaceous protective layer on the coating surface. The generation of the carbonaceous protective layer can isolate oxygen, prevent oxygen from contacting the unburned substances inside, and effectively block the transfer of heat, reducing the conduction of heat to the inside, protecting the internal materials of the coating, reducing the possibility and speed of combustion, and thus enhancing the flame retardant performance of the waterborne polyurethane resin.

[0030] In some embodiments, aluminum hydroxide is selected with a particle size ≤ 50 μm.

[0031] In some embodiments, rice bran is selected with a particle size ≤ 80 μm.

[0032] In some embodiments, the flame retardant is prepared by the following method: Weigh the first additive and the second additive as needed for preliminary mixing. After preliminary mixing, let it stand for 15 - 25 min, then put it into a mixing device for stirring. After stirring evenly, the flame retardant is prepared.

[0033] In this embodiment, after phytic acid binds to aluminum hydroxide, since the thermal decomposition temperature of aluminum hydroxide as a metal material is relatively fixed, while for phytic acid as a plant material, its thermal decomposition and carbonization processes can occur in a relatively low temperature range. Therefore, after phytic acid binds to aluminum hydroxide, the coating can provide flame retardant protection for the coating and the covering material in a relatively wide temperature range. When the coating does not directly contact the heat source during combustion, the coating can still provide good flame retardant protection performance, enhancing the flame retardant performance of the waterborne flame retardant polyurethane resin.

[0034] In some embodiments, the mixing speed of the mixing equipment is 1800 - 2200 rpm, and the mixing time is 15 - 25 min.

[0035] This embodiment also provides a preparation method of a waterborne flame - retardant polyurethane resin, comprising the following steps: S1: Weigh polyols and a flame retardant as required in a four - necked flask, introduce nitrogen into the four - necked flask, then add polyisocyanate, and obtain a prepolymer after a temperature - rising reaction. The reaction temperature is 80 - 90 °C, and the time is 2 - 4 h; S2: Wait for the prepolymer to cool down to 60 °C, add a chain extender and a catalyst, carry out a mixing reaction for 2 - 4 h, the mixing reaction temperature is 70 - 80 °C, then send the prepolymer into an emulsifying kettle, add a neutralizing agent, and add deionized water for emulsification treatment under high - speed shearing to obtain an emulsion; S3: Pour the emulsion into a distillation kettle, and obtain the waterborne flame - retardant polyurethane resin through vacuum treatment.

[0036] Based on the foregoing embodiments, the inventors also conducted the following multiple groups of experiments: It should be noted that the raw materials used in the following experiments are all commercially available raw materials.

[0037] Experiment 1: Preparation of phytic acid: Select rice bran as the raw material, the particle size of the rice bran is ≤80 μm, mix the rice bran with hydrochloric acid solution, the mass ratio of the rice bran to the hydrochloric acid solution is 1:4, stir and mix for 6 min, after mixing, heat to 40 °C, keep warm for 2 h, continuously stir during the heating and heat - preservation processes, then place it in a centrifuge, set the rotation speed to 3000 r / min, centrifuge for 8 min, and collect the supernatant after centrifugation; Preparation of the first additive: Add phytic acid to deionized water, the mass of phytic acid is 25% of the mass of deionized water, stir and mix, then add sodium hydroxide solution to adjust the pH value to 4, add aluminum hydroxide, the particle size of the aluminum hydroxide is ≤50 μm, the mass of the aluminum hydroxide is 80% of the mass of phytic acid, after preliminary mixing, place it on a magnetic stirrer, at room temperature, set the rotation speed to 500 r / min, and stir for 20 min; Preparation of the second additive: Crush and grind palm wax to obtain powdery palm wax, mix the powdery palm wax with xylene solution, the mass of the xylene solution is 2.5 times the mass of the powdery palm wax, after mixing, heat in a water bath to 90 °C, and stir evenly after the powdery palm wax melts; Preparation of the flame retardant: Weigh the first additive and the second additive as required for preliminary mixing, let it stand for 15 min after preliminary mixing, put it into a mixing equipment for stirring, the mixing speed of the mixing equipment is 1800 rpm, and the stirring time is 15 min; Preparation of waterborne flame-retardant polyurethane resin: Weigh 40 parts of polyol and 10 parts of flame retardant into a four-necked flask. Introduce nitrogen into the four-necked flask, and then add 10 parts of polyisocyanate. After heating and reacting, a prepolymer is obtained. The reaction temperature is 80 °C and the time is 2 h. When the prepolymer cools down to 60 °C, add 10 parts of chain extender and 2 parts of catalyst, and carry out a mixed reaction for 2 h. The mixed reaction temperature is 70 °C. Then, send the prepolymer into an emulsification kettle, add 2 parts of neutralizer, and carry out emulsification treatment with 120 parts of deionized water under high-speed shearing to obtain an emulsion. Introduce the emulsion into a distillation kettle and carry out vacuum treatment to obtain waterborne flame-retardant polyurethane resin.

[0038] Experiment Two: Preparation of phytic acid: Select rice bran as the raw material. The particle size of the selected rice bran is ≤80 μm. Mix the rice bran with hydrochloric acid solution. The mass ratio of rice bran to hydrochloric acid solution is 1:5. Stir and mix for 8 min. After mixing, heat to 60 °C and keep the temperature for 3 h. Stir continuously during the heating and heat preservation processes. Then, place it in a centrifuge, set the rotation speed to 3500 r / min, and carry out centrifugation for 10 min. After the centrifugation is completed, collect the supernatant. Preparation of the first additive: Add phytic acid to deionized water. The mass of phytic acid is 30% of the mass of deionized water. After stirring and mixing, add sodium hydroxide solution to adjust the pH value to 5. Add aluminum hydroxide. The particle size of the selected aluminum hydroxide is ≤50 μm. The mass of aluminum hydroxide is 85% of the mass of phytic acid. After preliminary mixing, place it on a magnetic stirrer and set the rotation speed to 600 r / min at room temperature and stir for 25 min. Preparation of the second additive: Crush and grind palm wax to obtain powdery palm wax. Mix the powdery palm wax with xylene solution. The mass of the xylene solution is 2.5 times the mass of the powdery palm wax. After mixing, heat in a water bath to 90 °C. After the powdery palm wax melts, stir evenly. Preparation of flame retardant: Weigh the first additive and the second additive as needed for preliminary mixing. After preliminary mixing, let it stand for 20 min, put it into a mixing equipment for stirring. The stirring speed of the mixing equipment is 2000 rpm and the stirring time is 20 min. Preparation of waterborne flame-retardant polyurethane resin: Weigh 50 parts of polyol and 15 parts of flame retardant into a four-necked flask. Introduce nitrogen into the four-necked flask, and then add 15 parts of polyisocyanate. After heating and reacting, a prepolymer is obtained. The reaction temperature is 85 °C and the time is 3 h. When the prepolymer cools down to 60 °C, add 15 parts of chain extender and 3 parts of catalyst, and carry out a mixed reaction for 3 h. The mixed reaction temperature is 75 °C. Then, send the prepolymer into an emulsification kettle, add 3 parts of neutralizer, and carry out emulsification treatment with 130 parts of deionized water under high-speed shearing to obtain an emulsion. Introduce the emulsion into a distillation kettle and carry out vacuum treatment to obtain waterborne flame-retardant polyurethane resin.

[0039] Experiment Three: Preparation of phytic acid: Select rice bran as the raw material. The particle size of the selected rice bran is ≤80 μm. Mix the rice bran with hydrochloric acid solution. The mass ratio of the rice bran to the hydrochloric acid solution is 1:6. Stir and mix for 10 min. After mixing, heat to 80 °C and keep the temperature for 4 h. Stir continuously during the heating and heat preservation processes. Then place it in a centrifuge, set the rotation speed to 4000 r / min, and centrifuge for 12 min. After the centrifugation is completed, collect the supernatant; Preparation of the first additive: Add phytic acid to deionized water. The mass of the phytic acid is 35% of the mass of the deionized water. After stirring and mixing, add sodium hydroxide solution to adjust the pH value to 6. Add aluminum hydroxide. The particle size of the selected aluminum hydroxide is ≤50 μm. The mass of the aluminum hydroxide is 90% of the mass of the phytic acid. After preliminary mixing, place it on a magnetic stirrer. Under room temperature conditions, set the rotation speed to 700 r / min and stir for 30 min; Preparation of the second additive: Crush and grind palm wax to obtain powdered palm wax. Mix the powdered palm wax with xylene solution. The mass of the xylene solution is 2.5 times the mass of the powdered palm wax. After mixing, heat in a water bath to 90 °C. After the powdered palm wax melts, stir evenly; Preparation of the flame retardant: Weigh the first additive and the second additive as needed for preliminary mixing. After preliminary mixing, let it stand for 25 min, then put it into a mixing equipment for stirring. The stirring speed of the mixing equipment is 2200 rpm, and the stirring time is 25 min; Preparation of waterborne flame retardant polyurethane resin: Weigh 60 parts of polyol and 20 parts of flame retardant into a four-necked flask. Pass nitrogen into the four-necked flask, and then add 20 parts of polyisocyanate. After heating and reacting, a prepolymer is obtained. The reaction temperature is 90 °C and the time is 4 h. When the prepolymer cools to 60 °C, add 20 parts of chain extender and 4 parts of catalyst, and carry out a mixing reaction for 4 h. The mixing reaction temperature is 80 °C. Then send the prepolymer into an emulsifying kettle, add 4 parts of neutralizing agent, and add 140 parts of deionized water for emulsification treatment under high-speed shearing to obtain an emulsion. Import the emulsion into a distillation kettle and carry out vacuum treatment to obtain waterborne flame retardant polyurethane resin.

[0040] Comparative example 1. The difference between this comparative example and Experimental example 1 is that: this comparative example does not contain phytic acid.

[0041] Comparative example 2. The difference between this comparative example and Experimental example 1 is that: this comparative example does not contain aluminum hydroxide.

[0042] Comparative example 3. The difference between this comparative example and Experimental example 1 is that: this comparative example does not contain functional additives.

[0043] Comparative example 4. The difference between this comparative example and Experimental example 1 is that: this comparative example does not add the first additive when preparing the functional additives.

[0044] Performance Test: The performance tests were carried out on the waterborne flame-retardant polyurethane resins prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4. The test data obtained were recorded in the following table:

[0045] In the performance test, according to the test methods in GB 12441-2018, the flame resistance and impact resistance of each waterborne flame-retardant polyurethane resin prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were respectively tested.

[0046] Among them, the flame-retardant times of each prepared waterborne flame-retardant polyurethane resin were 48 min, 51 min, 49 min, 22 min, 21 min, 15 min and 14 min respectively; The mass losses of each prepared waterborne flame-retardant polyurethane resin after combustion were 2.7 g, 2.2 g, 3.5 g, 8.4 g, 8.8 g, 11.5 g and 11.7 g respectively; The ultimate heights of the impact resistance tests of each prepared waterborne flame-retardant polyurethane resin were 35.9 cm, 38.1 cm, 36.4 cm, 16.7 cm, 18.2 cm, 15.6 cm and 17.6 cm respectively.

[0047] It can be seen that the flame resistance and impact resistance data of the waterborne flame-retardant polyurethane resins prepared in Comparative Examples 1, 2, 3 and 4 are lower than those in Experiment 1, Experiment 2 and Experiment 3. This shows that: after phytic acid is combined with aluminum hydroxide, since the thermal decomposition temperature of aluminum hydroxide as a metal material is relatively fixed, while phytic acid as a plant material, its thermal decomposition and carbonization processes can occur in a relatively low temperature range. Therefore, after phytic acid is combined with aluminum hydroxide, the coating can provide flame retardant protection for the coating and the covering material in a relatively wide temperature range. When the coating does not directly contact the heat source during combustion, the coating can still provide good flame retardant protection performance, improving the flame retardant performance of the waterborne flame-retardant polyurethane resin. Palm wax, as a hard wax with a relatively high flash point, has high hardness and wear resistance. After being added to the preparation of the waterborne polyurethane resin, it can improve the hardness and wear resistance of the coating.

[0048] By comparing and analyzing the relevant data in the table, it can be known that the waterborne flame-retardant polyurethane resin prepared by the present invention not only has good flame resistance, but also has excellent impact resistance. This shows that the method provided by the present invention for improving the corrosion resistance of magnesium alloys has a broader market prospect and is more suitable for popularization.

[0049] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection 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 specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0050] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A water-based flame-retardant polyurethane resin, characterized in that: The method comprises the following raw materials in parts by weight: 120 to 140 parts of deionized water, 40 to 60 parts of polyol, 10 to 20 parts of polyisocyanate, 10 to 20 parts of chain extender, 10 to 20 parts of flame retardant, 2 to 4 parts of catalyst and 2 to 4 parts of neutralizer; The flame retardant consists of a first additive and a second additive, and the mass ratio of the first additive to the second additive is 1:0.

5.

2. The water-based flame-retardant polyurethane resin according to claim 1, characterized in that: The first additive is prepared by the following method: adding phytic acid to deionized water, wherein the mass of the phytic acid is 25-35% of the mass of the deionized water, stirring and mixing, adding sodium hydroxide solution, adjusting the pH value to 4-6, adding aluminum hydroxide, wherein the mass of the aluminum hydroxide is 80-90% of the phytic acid, after preliminary mixing, placing on a magnetic stirrer, setting the speed to 500-700 r / min at room temperature, stirring for 20-30 minutes, and fully mixing to obtain the first additive.

3. The water-based flame-retardant polyurethane resin according to claim 2, characterized in that: After the first additive is mixed, it is placed in a stirrer and kept in a low-speed stirring state for standby use.

4. The water-based flame-retardant polyurethane resin according to claim 1, characterized in that: The second additive is prepared by the following method: crushing and grinding palm wax to obtain powdered palm wax, mixing the powdered palm wax with a xylene solution, wherein the mass of the xylene solution is 2.5 times the mass of the powdered palm wax, heating the mixed solution to 90°C in a water bath, and stirring evenly after the powdered palm wax is melted to obtain the second additive.

5. The water-based flame-retardant polyurethane resin according to claim 1, characterized in that: The phytic acid is prepared by the following method: selecting rice bran as a raw material, mixing the rice bran with a hydrochloric acid solution, wherein the mass ratio of the rice bran to the hydrochloric acid solution is 1:(4-6), stirring and mixing for 6-10 minutes, heating to 40-80°C after the mixing is completed, and keeping the temperature for reaction for 2-4 hours, stirring continuously during the heating and keeping temperature process, and then placing in a centrifuge, setting the speed to 3000-4000 r / min, centrifuging for 8-12 minutes, and collecting the supernatant after the centrifugation is completed to obtain the phytic acid.

6. The water-based flame-retardant polyurethane resin according to claim 2, characterized in that: The aluminum hydroxide has a particle size of ≤50 μm.

7. The water-based flame-retardant polyurethane resin according to claim 5, characterized in that: The rice bran has a particle size of ≤80 μm.

8. The water-based flame-retardant polyurethane resin according to claim 1, characterized in that: The flame retardant is prepared by the following method: weighing the first additive and the second additive as needed for preliminary mixing, standing for 15 to 25 minutes after preliminary mixing, putting them into a mixing device for stirring, and after stirring evenly, obtaining the flame retardant.

9. The water-based flame-retardant polyurethane resin according to claim 8, characterized in that: The stirring speed of the mixing equipment is 1800-2200 rpm, and the stirring time is 15-25 min.

10. A method for preparing a water-based flame-retardant polyurethane resin, characterized in that: Using a water-based flame-retardant polyurethane resin as claimed in any one of claims 1 to 9, The following steps are involved: S1: Weigh polyol and flame retardant as needed into a four-necked flask, introduce nitrogen into the four-necked flask, then add polyisocyanate, and obtain a prepolymer after heating reaction, wherein the reaction temperature is 80-90° C. and the reaction time is 2-4 hours; S2: After the prepolymer is cooled to 60°C, a chain extender and a catalyst are added, and the mixture is reacted for 2 to 4 hours at a temperature of 70 to 80°C. The prepolymer is then sent to an emulsification kettle, a neutralizer is added, and deionized water is added under high-speed shearing for emulsification treatment to obtain an emulsion; S3: Pour the emulsion into a distillation kettle and perform vacuum treatment to obtain a water-based flame-retardant polyurethane resin.

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