Non-MOCA type fitness equipment rubber coating material and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane materials, in particular to a non-MOCA type fitness equipment rubber coating material and a preparation method thereof. The preparation method comprises the following steps: adding polytetrahydrofuran, isophorone diisocyanate, 1, 4-butanediol, a 2, 2-dimethylolpropionic acid solution, a hydroxyl chain extender, triethylamine, deionized water and a flame-retardant filler to obtain a polyurethane emulsion; and coating the polyurethane emulsion to form a film, and drying to obtain the polyurethane adhesive film. Adding the flame-retardant filler into ethanol, and ultrasonically dispersing uniformly to obtain dispersion liquid; spraying the dispersion liquid onto the surface of a polyurethane adhesive film to obtain a pretreated polyurethane adhesive film; and carrying out layer-by-layer self-assembly on the surface of the pretreated polyurethane adhesive film for 5-6 times to obtain a finished product. The finished product prepared by the invention has excellent flame retardant property, antibacterial property and mechanical property, thereby having wide application prospect in the technical field of polyurethane materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane materials, in particular to a non-MOCA type fitness equipment encapsulating material and a preparation method thereof. BACKGROUND

[0002] Traditional MOCA type encapsulating materials contain carcinogenic components, while non-MOCA type polyurethane encapsulating materials do not use MOCA, greatly reducing the release of harmful substances. In today's growing concern for health and environmental protection, non-MOCA type fitness equipment encapsulating materials provide a safe fitness environment for fitness enthusiasts, meeting the demand for green products in modern society. However, fitness places are crowded and usually equipped with a large number of electrical equipment. Once a fire occurs, ordinary encapsulating materials are easy to burn and produce a large amount of toxic smoke, which can seriously threaten people's life safety. Therefore, polyurethane encapsulating materials with good flame retardant properties are needed to effectively slow down the burning speed and reduce the release of toxic gases when encountering a fire source, gaining valuable time for personnel evacuation and fire rescue. Furthermore, fitness equipment will come into direct contact with many users during use, and is prone to breed a large number of bacteria and viruses. Polyurethane encapsulating materials with good antibacterial properties can inhibit the growth of bacteria and viruses, effectively reducing the risk of disease transmission and providing a healthier and safer fitness environment for users. At the same time, fitness equipment will be subjected to frequent friction, compression and stretching forces in daily use. If the mechanical properties of the encapsulating material are not good, it is easy to appear problems such as wear and tear, cracking, etc., which not only affects the service life of the equipment, but also may cause equipment failure and safety accidents. By improving the mechanical properties of the encapsulating material, such as enhancing wear resistance, tear resistance and tensile strength, etc., the encapsulating material can better withstand various external forces, ensuring the stability and reliability of the fitness equipment, prolonging its service life and reducing maintenance and replacement costs.

[0003] In order to overcome the defects of the prior art, the present application provides a non-MOCA type fitness equipment encapsulating material and a preparation method thereof. SUMMARY

[0004] The purpose of the present application is to provide a non-MOCA type fitness equipment encapsulating material and a preparation method thereof to solve the problems existing in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A preparation method of a non-MOCA type fitness equipment encapsulating material, comprising the following steps:

[0007] Step one: under the nitrogen environment, polytetrahydrofuran, isophorone diisocyanate, 1,4-butanediol, 2,2-dimethylol propionic acid solution is mixed, and the reaction is carried out at 70-75℃ for 3.5-4.5h, after the reaction of this stage is completed, the temperature is lowered to 55-60℃, and then the hydroxyl chain extender is added and reacted for 50-60min, after the reaction of this stage is completed, the temperature is lowered to 40-45℃, and then triethylamine is added and the reaction is continued for 40-60min, after the reaction is completed, deionized water is added and stirred for emulsification for 40-60min, then the flame-retardant filler is added and stirred for 20-25min, and a polyurethane emulsion is obtained; the polyurethane emulsion is coated into a film, and after drying, a polyurethane adhesive film is obtained;

[0008] Step two: the flame-retardant filler is added to ethanol, and ultrasonic dispersion is carried out for 20-30min to obtain a dispersion liquid; the dispersion liquid is sprayed onto the surface of the polyurethane adhesive film, and after the spraying is completed, the film is dried at 90-100℃ for 10-15min to obtain a pretreated polyurethane adhesive film;

[0009] Step three: the pretreated polyurethane adhesive film is immersed in a 0.2-0.3wt% polyethyleneimine solution for 3-5min, dried, and then immersed in a 1.2-1.5wt% polyacrylic acid solution for 3-5min to obtain a modified polyurethane adhesive film; then the modified polyurethane adhesive film is immersed in a cationic solution for 3-5min, dried, and then immersed in an anionic solution for 3-5min, and after drying, the first surface assembly of the modified polyurethane adhesive film is completed; the surface assembly of the modified polyurethane adhesive film is repeated for 5-6 times to obtain a finished product.

[0010] More preferably, in step one, 2,2-dimethylol propionic acid is dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution; the content of each component of the polyurethane emulsion is as follows: 40-50 parts of polytetrahydrofuran, 30-35 parts of isophorone diisocyanate, 6-8 parts of 1,4-butanediol, 8-10 parts of 2,2-dimethylol propionic acid, 15-20 parts of N-methyl pyrrolidone, 6-8 parts of hydroxyl chain extender, 3-4 parts of triethylamine, 130-150 parts of deionized water, and 8-10 parts of flame-retardant filler.

[0011] More preferably, in step two, the mass-volume ratio of the flame-retardant filler and ethanol is 0.03g:(5-6)mL.

[0012] More preferably, in step three, chitosan is dissolved in a 0.9-1.0wt% acetic acid solution to obtain a 1.0-1.2wt% chitosan solution; ammonium polyphosphate is added and dispersed in deionized water to obtain a 4.8-5.0wt% ammonium polyphosphate solution; and sodium hexametaphosphate is dissolved in deionized water to obtain a 1.3-1.5wt% sodium hexametaphosphate solution.

[0013] The chitosan solution is added dropwise to the ammonium polyphosphate solution, and after the addition is completed, it is left to stand for 3-5 min, and then centrifuged, washed, and dried to obtain a chitosan coating; the chitosan coating is dissolved in a 0.9-1.0 wt% acetic acid solution to obtain a 1.5-1.7 wt% cationic solution; the sodium hexametaphosphate solution is added dropwise to the chitosan solution, and after the addition is completed, it is left to stand for 3-5 min, and then centrifuged, washed, and dried to obtain a sodium hexametaphosphate coating; the sodium hexametaphosphate coating is dissolved in deionized water to obtain a 1.5-1.7 wt% anionic solution; and the thickness of the finished encapsulating material is 3-4 mm.

[0014] More preferably, the preparation process of the hydroxyl chain extender is as follows: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and reacted at 25-30°C in the dark for 45-50 h; after the reaction is completed, it is centrifuged, washed, and dried to obtain the hydroxyl chain extender.

[0015] More preferably, the molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1:

[0016] (1.1-1.2).

[0017] More preferably, the preparation process of the flame-retardant filler is as follows:

[0018] Step S1: γ-aminopropyltriethoxysilane is added to deionized water, and a 0.9-1.0 wt% acetic acid solution is added to adjust the pH to 3.0-3.5 to obtain a silane coupling agent solution; α-alumina is added to a mixture of ethanol and deionized water, uniformly dispersed by ultrasonic, and then the silane coupling agent solution is added, refluxed at 80-85°C for 6-8 h, and after the reaction is completed, it is centrifuged, washed, and dried to obtain pretreated alumina;

[0019] Step S2: under a nitrogen environment, hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina are added to tetrahydrofuran, uniformly dispersed by ultrasonic to obtain a hexachlorocyclotriphosphazene solution, a triethylamine solution, and a pretreated alumina solution, respectively; the triethylamine solution is slowly added to the hexachlorocyclotriphosphazene solution, heated to 60-65°C after the addition is completed, and then the pretreated alumina solution is added dropwise, and after the addition is completed, the reaction is continued for 10-12 h; after the reaction is completed, impurities are removed by filtration, washed, centrifuged, washed again, dried, ground, and the flame-retardant filler is obtained.

[0020] More preferably, in step S1, the mass-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution is 0.3 g:(8-9) mL; and when the pretreated alumina is prepared, the mass-volume ratio of α-alumina, the silane coupling agent solution, ethanol, and deionized water is (4.0-4.5) g:4 mL:100 mL:100 mL.

[0021] More preferably, in step S2, the reaction mass ratio of hexachlorocyclotriphosphazene, triethylamine and pretreated alumina is 1.4:3:(9-10).

[0022] Advantages of the present application:

[0023] The present application is characterized in that, in step one, polytetrahydrofuran, isophorone diisocyanate, 1,4-butanediol, 2,2-dimethylol propionic acid solution, hydroxyl chain extender, triethylamine, deionized water and flame-retardant filler are added to obtain a polyurethane emulsion; the polyurethane emulsion is coated into a film, and after drying, a polyurethane adhesive film is obtained. The hydroxyl chain extender prepared by the reaction of diisopropanolamine and 4-formylphenylboronic acid contains multiple hydroxyl groups. During the synthesis of polyurethane, these hydroxyl groups can react with the isocyanate groups in isophorone diisocyanate, causing the polyurethane molecular chain to expand. The expansion of the molecular chain increases the molecular weight and chain length of the polyurethane molecule, and the entanglement between the longer molecular chains is enhanced, which can better resist external stretching force, so that the adhesive film is not easy to break when under stress, improving the mechanical properties of the adhesive film. In addition, alpha-alumina as a rigid filler can disperse stress and improve the hardness and rigidity of the adhesive film. When the adhesive film is subjected to external force, the alumina particles can bear part of the stress, reducing the stress on the polyurethane molecular chain, thereby improving the mechanical properties of the adhesive film.

[0024] In addition, the flame-retardant filler is prepared by modifying alpha-alumina and introducing flame-retardant elements such as hexachlorocyclotriphosphazene. Phosphorus elements can form phosphoric acid, metaphosphoric acid and other substances during combustion, which can promote the dehydration of polyurethane to form carbon, forming a dense carbon layer to prevent combustion. And alumina itself has good thermal stability and heat insulation performance, which can absorb a large amount of heat during combustion, slowing down the combustion speed. Pretreated alumina modified by γ-aminopropyl triethoxysilane can be better dispersed in the polyurethane matrix, improving the uniformity of the flame-retardant effect. Furthermore, the hydroxyl chain extender contains flame-retardant boric acid groups, which can undergo a series of chemical reactions during combustion to form a borate protective film, isolating the transfer of oxygen and heat and preventing further spread of combustion.

[0025] The application is characterized in that, in step two, the prepared flame-retardant filler is added to ethanol and uniformly dispersed by ultrasonic to obtain a dispersion liquid; and the dispersion liquid is sprayed onto the surface of the polyurethane adhesive film to obtain a pretreated polyurethane adhesive film. When the flame-retardant filler dispersion liquid is sprayed onto the surface of the polyurethane adhesive film, the flame-retardant filler particles will adhere to the surface of the adhesive film to form a rough microstructure. When the surface coating is self-assembled subsequently, the larger specific surface area means more physical adsorption sites, which increases the bonding force between the coating and the adhesive film, so that the self-assembled coating is more stable and less likely to fall off. In addition, the rough mechanical interlocking structure formed by spraying the rigid filler dispersion liquid can effectively disperse various external forces and avoid stress concentration at the interface between the coating and the adhesive film, thereby reducing the damage to the coating and the adhesive film and prolonging the service life of the coating.

[0026] The application is characterized in that, in step three, the chitosan solution is added dropwise to the ammonium polyphosphate solution to obtain a chitosan coating by electrostatic self-assembly; then the chitosan coating is dissolved in acetic acid solution to obtain a cationic solution; the sodium hexametaphosphate solution is added dropwise to the chitosan solution to obtain a sodium hexametaphosphate coating by electrostatic self-assembly; and then the sodium hexametaphosphate coating is dissolved in deionized water to obtain an anionic solution. The modified polyurethane adhesive film obtained by preliminary modification is immersed in the cationic solution, dried, then immersed in the anionic solution, and dried to complete the first surface assembly of the modified polyurethane adhesive film; the surface assembly of the modified polyurethane adhesive film is repeated for 5-6 times to obtain a finished product. On the one hand, ammonium polyphosphate and sodium hexametaphosphate both have certain flame-retardant properties, and the coating structure formed by coating ammonium polyphosphate with chitosan and coating chitosan with sodium hexametaphosphate will form a relatively dense flame-retardant coating on the surface of the polyurethane adhesive film after multiple surface assemblies, which plays a role in heat insulation and oxygen insulation, prevents oxygen from contacting the combustible substances inside the adhesive film, slows down the burning speed, and reduces the risk of fire. On the other hand, chitosan has good biocompatibility and antibacterial properties. After surface assembly, the adhesive film surface contains chitosan components, which have excellent antibacterial properties. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0028] Raw material sources:

[0029] Alpha-alumina, provided by Linglu New Material Technology Co., Ltd. in Nangong City, particle size 2000 mesh; polytetrahydrofuran, provided by Shandong Yuxuan Chemical Product Co., Ltd., molecular weight 2000; chitosan, provided by Aladdin, deacetylation ≥95%; ammonium polyphosphate, provided by Shandong Buniu Chemical Co., Ltd., particle size 100 mesh; polyethylene imine, provided by Aladdin, purity ≥99.5%; polyacrylic acid, provided by Aladdin, purity ≥99.5%; in mass fraction, one part is 1 g.

[0030] Example 1: Step S1: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and reacted at 30°C in the dark for 50 h. After the reaction is completed, centrifugation, washing, and drying are performed to obtain a hydroxyl chain extender. The reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1:1.15;

[0031] Step S2: γ-aminopropyltriethoxysilane is added to deionized water, and a 1.0 wt% acetic acid solution is added to adjust the pH to 3.5 to obtain a silane coupling agent solution. Alpha-alumina is added to a mixture of ethanol and deionized water, ultrasonically dispersed uniformly, and then the silane coupling agent solution is added. Refluxing is performed at 85°C for 8 h. After the reaction is completed, centrifugation, washing, and drying are performed to obtain pretreated alumina. The mass-to-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution is 0.3 g:8.5 mL. When preparing the pretreated alumina, the mass-to-volume ratio of alpha-alumina, the silane coupling agent solution, ethanol, and deionized water is 4.3 g:4 mL:100 mL:100 mL;

[0032] Step S3: under a nitrogen environment, hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina are added to tetrahydrofuran, ultrasonically dispersed uniformly, and then hexachlorocyclotriphosphazene solution, triethylamine solution, and pretreated alumina solution are obtained in sequence. The triethylamine solution is slowly added to the hexachlorocyclotriphosphazene solution. After the addition is completed, the temperature is raised to 65°C, and then the pretreated alumina solution is added. After the addition is completed, the reaction is continued for 12 h. After the reaction is completed, impurities are removed by filtration, washing, centrifugation, re-washing, drying, and grinding to obtain a flame-retardant filler. The reaction mass ratio of hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina is 1.4:3:9.5;

[0033] Step S4: 50 g of polytetrahydrofuran, 35 g of isophorone diisocyanate, 8 g of 1,4-butanediol, 30 g of 2,2-dimethylol propionic acid solution were mixed under a nitrogen environment, and reacted at 75°C for 4.5 h. After the reaction in this stage was completed, the temperature was lowered to 60°C, 8 g of a hydroxyl chain extender was added, and reacted for 60 min. After the reaction in this stage was completed, the temperature was lowered to 45°C, 4 g of triethylamine was added, and reacted for 60 min. After the reaction was completed, 150 g of deionized water was added, stirred and emulsified for 60 min, 10 g of a flame-retardant filler was added, and stirred for 25 min to obtain a polyurethane emulsion. The polyurethane emulsion was coated into a film, and after drying, a polyurethane adhesive film was obtained. 2,2-dimethylol propionic acid was dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution;

[0034] Step S5: The flame-retardant filler was added to ethanol, and ultrasonic dispersion was performed for 30 min to obtain a dispersion liquid. The dispersion liquid was sprayed onto the surface of the polyurethane adhesive film, and after the spraying was completed, the film was dried at 100°C for 15 min to obtain a pretreated polyurethane adhesive film. The mass-volume ratio of the flame-retardant filler and ethanol was 0.03 g:5.5 mL.

[0035] Step S6: Chitosan was dissolved in a 1.0 wt% acetic acid solution to obtain a 1.2 wt% chitosan solution. Ammonium polyphosphate was added and dispersed in deionized water to obtain a 5.0 wt% ammonium polyphosphate solution. Sodium hexametaphosphate was dissolved in deionized water to obtain a 1.5 wt% sodium hexametaphosphate solution.

[0036] The chitosan solution was added dropwise to the ammonium polyphosphate solution, and after the addition was completed, the mixture was allowed to stand for 5 min. After centrifugation, washing, and drying, a chitosan coating was obtained. The chitosan coating was dissolved in a 1.0 wt% acetic acid solution to obtain a 1.7 wt% cationic solution. The sodium hexametaphosphate solution was added dropwise to the chitosan solution, and after the addition was completed, the mixture was allowed to stand for 5 min. After centrifugation, washing, and drying, a sodium hexametaphosphate coating was obtained. The sodium hexametaphosphate coating was dissolved in deionized water to obtain a 1.7 wt% anionic solution.

[0037] The pretreated polyurethane adhesive film was immersed in a 0.3 wt% polyethyleneimine solution for 5 min, dried, and then immersed in a 1.5 wt% polyacrylic acid solution for 5 min to obtain a modified polyurethane adhesive film. The modified polyurethane adhesive film was then immersed in the cationic solution for 5 min, dried, and then immersed in the anionic solution for 5 min. After drying, the first surface assembly of the modified polyurethane adhesive film was completed. The surface assembly of the modified polyurethane adhesive film was repeated a total of 5 times to obtain a finished product. The thickness of the finished product was 3 mm.

[0038] Example 2: Step S1: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and reacted at 27°C for 47 hours in the dark. After the reaction is completed, centrifugation, washing, and drying are performed to obtain the hydroxyl chain extender. The reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1:1.15;

[0039] Step S2: γ-aminopropyltriethoxysilane is added to deionized water, and a 0.95wt% acetic acid solution is added to adjust the pH to 3.2 to obtain a silane coupling agent solution; α-alumina is added to a mixture of ethanol and deionized water, and the silane coupling agent solution is added after ultrasonic dispersion to obtain a pretreated alumina. The pretreated alumina is obtained by refluxing at 82°C for 7 hours. After the reaction is completed, centrifugation, washing, and drying are performed. The mass-to-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution is 0.3g:8.5mL. When preparing the pretreated alumina, the mass-to-volume ratio of α-alumina, the silane coupling agent solution, ethanol, and deionized water is 4.3g:4mL:100mL:100mL.

[0040] Step S3: Under a nitrogen environment, hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina are added to tetrahydrofuran, respectively, and ultrasonic dispersion is performed to obtain a hexachlorocyclotriphosphazene solution, a triethylamine solution, and a pretreated alumina solution, respectively. The triethylamine solution is slowly added to the hexachlorocyclotriphosphazene solution, and the temperature is raised to 62°C after the addition is completed. The pretreated alumina solution is then added, and the reaction is continued for 11 hours after the addition is completed. After the reaction is completed, impurities are removed by filtration, washing, centrifugation, re-washing, drying, and grinding to obtain a flame-retardant filler. The reaction mass ratio of hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina is 1.4:3:9.5.

[0041] Step S4: Under a nitrogen environment, 50g of polytetrahydrofuran, 35g of isophorone diisocyanate, 8g of 1,4-butanediol, and 30g of a 2,2-dimethylol propionic acid solution are mixed and reacted at 72°C for 4 hours. After the reaction in this stage is completed, the temperature is lowered to 57°C, 8g of a hydroxyl chain extender is added, and the reaction is continued for 55 minutes. After the reaction in this stage is completed, the temperature is lowered to 42°C, 4g of triethylamine is added, and the reaction is continued for 50 minutes. After the reaction is completed, 150g of deionized water is added and stirred for 50 minutes to emulsify. Then, 10g of a flame-retardant filler is added and stirred for 23 minutes to obtain a polyurethane emulsion. The polyurethane emulsion is coated to form a film, and the polyurethane adhesive film is obtained after drying. The 2,2-dimethylol propionic acid is dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution.

[0042] Step S5: The flame-retardant filler is added to ethanol and ultrasonic dispersed for 25 minutes to obtain a dispersion liquid. The dispersion liquid is sprayed onto the surface of the polyurethane adhesive film, and the film is dried at 95°C for 12 minutes to obtain a pretreated polyurethane adhesive film. The mass-to-volume ratio of the flame-retardant filler to ethanol is 0.03g:5.5mL.

[0043] Step S6: chitosan was dissolved in 0.95wt% acetic acid solution to obtain a 1.1wt% chitosan solution; ammonium polyphosphate was added and dispersed in deionized water to obtain a 4.9wt% ammonium polyphosphate solution; sodium hexametaphosphate was dissolved in deionized water to obtain a 1.4wt% sodium hexametaphosphate solution;

[0044] The chitosan solution was added dropwise to the ammonium polyphosphate solution, and after the addition was completed, it was left to stand for 4min, and then centrifuged, washed and dried to obtain a chitosan coating; the chitosan coating was dissolved in 0.95wt% acetic acid solution to obtain a 1.6wt% cation solution; the sodium hexametaphosphate solution was added dropwise to the chitosan solution, and after the addition was completed, it was left to stand for 4min, and then centrifuged, washed and dried to obtain a sodium hexametaphosphate coating; the sodium hexametaphosphate coating was dissolved in deionized water to obtain a 1.6wt% anion solution;

[0045] The pretreated polyurethane adhesive film was immersed in a 0.25wt% polyethyleneimine solution for 4min, then dried and immersed in a 1.4wt% polyacrylic acid solution for 4min to obtain a modified polyurethane adhesive film; the modified polyurethane adhesive film was then immersed in the cation solution for 4min, then dried and immersed in the anion solution for 4min, and then dried to complete the first surface assembly of the modified polyurethane adhesive film; the surface assembly of the modified polyurethane adhesive film was repeated a total of 5 times to obtain a finished product; the thickness of the finished encapsulating material was 3mm.

[0046] Example 3: Step S1: diisopropanolamine and 4-formylphenylboronic acid were added to anhydrous methanol, stirred uniformly, and then reacted at 25°C in the dark for 45h; after the reaction was completed, the product was centrifuged, washed and dried to obtain a hydroxyl chain extender; the reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid was 1:1.15;

[0047] Step S2: γ-aminopropyltriethoxysilane was added to deionized water, and 0.9wt% acetic acid solution was added to adjust the pH to 3 to obtain a silane coupling agent solution; α-alumina was added to a mixture of ethanol and deionized water, and the mixture was uniformly dispersed by ultrasonic, then the silane coupling agent solution was added, and the mixture was refluxed at 80°C for 6h; after the reaction was completed, the product was centrifuged, washed and dried to obtain pretreated alumina; the mass-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution was 0.3g:8.5mL; when preparing the pretreated alumina, the mass-volume ratio of α-alumina, silane coupling agent solution, ethanol and deionized water was 4.3g:4mL:100mL:100mL;

[0048] Step S3: under the environment of nitrogen, hexachlorocyclotriphosphazene, triethylamine, pretreated alumina were added into tetrahydrofuran respectively, and were uniformly dispersed by ultrasonic, then hexachlorocyclotriphosphazene solution, triethylamine solution, pretreated alumina solution were obtained in turn; the triethylamine solution was slowly added into the hexachlorocyclotriphosphazene solution, after the addition was completed, the temperature was raised to 60℃, then the pretreated alumina solution was added dropwise, after the addition was completed, the reaction was continued for 10h, after the reaction was completed, impurities were removed by filtration, washing, centrifugation, re-washing, drying and grinding, the flame retardant filler was obtained; the mass ratio of hexachlorocyclotriphosphazene, triethylamine and pretreated alumina was 1.4:3:9.5;

[0049] Step S4: under the environment of nitrogen, 50g of polytetrahydrofuran, 35g of isophorone diisocyanate, 8g of 1,4-butanediol, 30g of 2,2-dimethylol propionic acid solution were mixed, and reacted at 70℃ for 3.5h, after the reaction was completed, the temperature was lowered to 55℃, then 8g of hydroxyl chain extender was added and reacted for 50min, after the reaction was completed, the temperature was lowered to 40℃, then 4g of triethylamine was added and reacted for 40min, after the reaction was completed, 150g of deionized water was added and stirred for emulsification for 40min, then 10g of flame retardant filler was added and stirred for 20min, polyurethane emulsion was obtained; the polyurethane emulsion was coated into a film, and after drying, polyurethane adhesive film was obtained; 2,2-dimethylol propionic acid was dissolved in N-methyl pyrrolidone to obtain 2,2-dimethylol propionic acid solution;

[0050] Step S5: the flame retardant filler was added into ethanol, and was ultrasonically dispersed for 20min to obtain a dispersion liquid; the dispersion liquid was sprayed onto the surface of the polyurethane adhesive film, and after the spraying was completed, the pretreated polyurethane adhesive film was obtained by drying at 90℃ for 10min; the mass-volume ratio of the flame retardant filler and ethanol was 0.03g:5.5mL;

[0051] Step S6: chitosan was dissolved in 0.9wt% acetic acid solution to obtain 1.0wt% chitosan solution; ammonium polyphosphate was added and dispersed in deionized water to obtain 4.8wt% ammonium polyphosphate solution; sodium hexametaphosphate was dissolved in deionized water to obtain 1.3wt% sodium hexametaphosphate solution;

[0052] The chitosan solution was added dropwise into the ammonium polyphosphate solution, and after the addition was completed, it was placed for 3min, then was centrifuged, washed and dried to obtain chitosan coating; the chitosan coating was dissolved in 0.9wt% acetic acid solution to obtain 1.5wt% cationic solution; the sodium hexametaphosphate solution was added dropwise into the chitosan solution, and after the addition was completed, it was placed for 3min, then was centrifuged, washed and dried to obtain sodium hexametaphosphate coating; the sodium hexametaphosphate coating was dissolved in deionized water to obtain 1.5wt% anionic solution;

[0053] The pretreated polyurethane adhesive film is immersed in a 0.2wt% polyethyleneimine solution for 3 minutes, dried, and then immersed in a 1.2wt% polyacrylic acid solution for 3 minutes to obtain a modified polyurethane adhesive film; the modified polyurethane adhesive film is then immersed in a cationic solution for 3 minutes, dried, and then immersed in an anionic solution for 3 minutes, and dried to complete the first surface assembly of the modified polyurethane adhesive film; the surface assembly of the modified polyurethane adhesive film is repeated for a total of 5 times to obtain a finished product; the thickness of the finished product is 3mm.

[0054] Comparative Example 1: The flame-retardant filler is removed, and the remaining steps are the same as those in Example 1, and the specific steps are as follows: Step S1: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and reacted at 30°C for 50 hours in the dark. After the reaction is completed, centrifugation, washing, and drying are performed to obtain a hydroxyl chain extender; the reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1:1.15;

[0055] Step S2: 50g of polytetrahydrofuran, 35g of isophorone diisocyanate, 8g of 1,4-butanediol, and 30g of 2,2-dimethylol propionic acid solution are mixed and reacted at 75°C for 4.5 hours. After the reaction in this stage is completed, the temperature is lowered to 60°C, 8g of the hydroxyl chain extender is added, and the reaction is continued for 60 minutes. After the reaction in this stage is completed, the temperature is lowered to 45°C, 4g of triethylamine is added, and the reaction is continued for 60 minutes. After the reaction is completed, 150g of deionized water is added, stirred and emulsified for 60 minutes to obtain a polyurethane emulsion. The polyurethane emulsion is coated to form a film, which is dried to obtain a polyurethane adhesive film. 2,2-dimethylol propionic acid is dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution;

[0056] Step S3: Chitosan is dissolved in a 1.0wt% acetic acid solution to obtain a 1.2wt% chitosan solution; ammonium polyphosphate is added and dispersed in deionized water to obtain a 5.0wt% ammonium polyphosphate solution; sodium hexametaphosphate is dissolved in deionized water to obtain a 1.5wt% sodium hexametaphosphate solution;

[0057] The chitosan solution is added dropwise to the ammonium polyphosphate solution, and after the addition is completed, it is left to stand for 5 minutes, and then centrifuged, washed, and dried to obtain a chitosan coating; the chitosan coating is dissolved in a 1.0wt% acetic acid solution to obtain a 1.7wt% cationic solution; the sodium hexametaphosphate solution is added dropwise to the chitosan solution, and after the addition is completed, it is left to stand for 5 minutes, and then centrifuged, washed, and dried to obtain a sodium hexametaphosphate coating; the sodium hexametaphosphate coating is dissolved in deionized water to obtain a 1.7wt% anionic solution;

[0058] The polyurethane adhesive film is immersed in a 0.3wt% polyethyleneimine solution for 5 minutes, dried, and then immersed in a 1.5wt% polyacrylic acid solution for 5 minutes to obtain a modified polyurethane adhesive film; the modified polyurethane adhesive film is then immersed in a cationic solution for 5 minutes, dried, and then immersed in an anionic solution for 5 minutes, and dried to complete the first surface assembly of the modified polyurethane adhesive film; the surface assembly of the modified polyurethane adhesive film is repeated for a total of 5 times to obtain a finished product; the thickness of the finished product is 3mm.

[0059] Comparative Example 2: Step S6 is removed, and the remaining steps are the same as those in Example 1, and the specific steps are as follows: Step S1: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and reacted at 30°C for 50h in the dark. After the reaction is completed, centrifugation, washing, and drying are performed to obtain a hydroxyl chain extender; the reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1:1.15;

[0060] Step S2: γ-aminopropyltriethoxysilane is added to deionized water, and a 1.0wt% acetic acid solution is added to adjust the pH to 3.5 to obtain a silane coupling agent solution; α-alumina is added to a mixture of ethanol and deionized water, ultrasonically dispersed uniformly, and then the silane coupling agent solution is added, and refluxed at 85°C for 8h. After the reaction is completed, centrifugation, washing, and drying are performed to obtain pretreated alumina; the mass-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution is 0.3g:8.5mL; when preparing the pretreated alumina, the mass-volume ratio of α-alumina, silane coupling agent solution, ethanol, and deionized water is 4.3g:4mL:100mL:100mL;

[0061] Step S3: under a nitrogen environment, hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina are added to tetrahydrofuran, ultrasonically dispersed uniformly, and then hexachlorocyclotriphosphazene solution, triethylamine solution, and pretreated alumina solution are obtained in sequence; the triethylamine solution is slowly added to the hexachlorocyclotriphosphazene solution, and then the temperature is raised to 65°C; the pretreated alumina solution is added, and the reaction is continued for 12h after the addition is completed; after the reaction is completed, impurities are removed by filtration, washed, centrifuged, washed again, dried, ground, and then a flame-retardant filler is obtained; the reaction mass ratio of hexachlorocyclotriphosphazene, triethylamine, and pretreated alumina is 1.4:3:9.5;

[0062] Step S4: 50 g of polytetrahydrofuran, 35 g of isophorone diisocyanate, 8 g of 1,4-butanediol, 30 g of 2,2-dimethylol propionic acid solution were mixed under a nitrogen environment, and reacted at 75°C for 4.5 h. After the reaction in this stage was completed, the temperature was lowered to 60°C, 8 g of a hydroxyl chain extender was added, and reacted for 60 min. After the reaction in this stage was completed, the temperature was lowered to 45°C, 4 g of triethylamine was added, and reacted for 60 min. After the reaction was completed, 150 g of deionized water was added, emulsified by stirring for 60 min, 10 g of a flame-retardant filler was added, and stirred for 25 min to obtain a polyurethane emulsion. The polyurethane emulsion was coated to form a film, and after drying, a polyurethane adhesive film was obtained. 2,2-dimethylol propionic acid was dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution;

[0063] Step S5: The flame-retardant filler was added to ethanol, and ultrasonically dispersed for 30 min to obtain a dispersion liquid. The dispersion liquid was sprayed onto the surface of the polyurethane adhesive film, and after the spraying was completed, the product was obtained by drying at 100°C for 15 min. The mass-volume ratio of the flame-retardant filler and ethanol was 0.03 g:5.5 mL. The thickness of the finished product, the encapsulating material, was 3 mm.

[0064] Detection test:

[0065] Flame-retardant oxygen index test: The finished product prepared by the present application was cut into a sample with a size of 120x6x3 mm, and a J-3 type limiting oxygen index instrument was used to test the oxygen index of the sample.

[0066] Antibacterial test: The finished product prepared by the present application was cut into a sample with a size of 120x6x3 mm. Escherichia coli was selected and placed in a bacterial culture solution to be incubated at 35°C to obtain a bacterial solution. PBS buffer was added to dilute the bacterial solution to a concentration of 1x10 6 CFU / mL, and the diluted bacterial solution was uniformly coated on the surface of the sample. The sample was incubated at 35°C for 5 h. The incubated sample was placed in a sterile centrifuge tube, physiological saline was added and vortexed thoroughly. The surviving cells were recovered, diluted and cultured on a solid agar medium at 35°C for 24 h. After incubation, the number of colonies in the culture medium was counted. Under the same conditions, a blank group was set up, and the corresponding data was introduced into the formula to calculate the antibacterial rate.

[0067] Mechanical property test: Referring to the GB / T 1040.1-2018 “Determination of tensile properties of plastics-Part 1: General principles” standard, the finished product prepared by the present application was cut into a sample with a size of 75x12.5x3 mm, and the tensile strength of the sample was tested at a tensile rate of 200 mm / min. The results are as follows:

[0068] Oxygen index / % Bacteriostatic rate / % Tensile strength / MPa Example 1 31.2 91.6 29.6 Example 2 31.1 91.4 29.5 Example 3 30.8 91.3 29.5 Comparative Example 1 27.4 89.1 25.1 Comparative Example 2 22.6 67.3 28.8

[0069] Conclusion: The amount of Example 1-Example 3 is unchanged, only modify part of the reaction parameters. From the experimental data, the performance of the sample has no significant fluctuations.

[0070] Comparative Example 1: Remove the flame retardant filler, the rest is the same as Example 1, from the experimental data, compared with Example 1, the oxygen index is reduced to 27.4%, the tensile strength is reduced to 25.1MPa, the analysis reason is: the flame retardant filler is formed by the surface of aluminum oxide coated with flame retardant elements with good thermal stability and heat insulation performance, so it has excellent flame retardant performance, so after removing it, the oxygen index is reduced; In addition, α-alumina as a rigid filler can improve the mechanical properties of the film, so after removing it, the tensile strength is reduced.

[0071] Comparative Example 2: Remove step S6, the rest is the same as Example 1, from the experimental data, compared with Example 1, the oxygen index is reduced to 22.6%, the bacteriostatic rate is reduced to 67.3%, the analysis reason is: the modified polyurethane film is immersed in cationic solution and anionic solution for many times in step S6, the obtained sample has excellent flame retardant performance and antibacterial performance, so after removing it, the flame retardant performance and antibacterial performance are reduced.

[0072] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process method article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process method article or equipment.

[0073] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the limitation of the present application, although the present application is described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can modify the technical scheme recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of preparing a non-MOCA type fitness equipment encapsulant material, characterized by: Comprising the following steps: Step one: under the nitrogen environment, polytetrahydrofuran, isophorone diisocyanate, 1,4-butanediol, 2,2-dimethylol propionic acid solution is mixed, and the reaction is carried out at 70-75 DEG C for 3.5-4.5 h, after the reaction of this stage is completed, the temperature is lowered to 55-60 DEG C, and then the hydroxyl chain extender is added and reacted for 50-60 min, after the reaction of this stage is completed, the temperature is lowered to 40-45 DEG C, and then triethylamine is added and the reaction is continued for 40-60 min, after the reaction is completed, deionized water is added and stirred for emulsification for 40-60 min, then flame-retardant filler is added and stirred for 20-25 min, and then the polyurethane emulsion is obtained; the polyurethane emulsion is coated into a film, and after drying, the polyurethane adhesive film is obtained; Step two: the flame-retardant filler is added to ethanol, and ultrasonic dispersion is carried out for 20-30 min to obtain a dispersion liquid; the dispersion liquid is sprayed onto the surface of the polyurethane adhesive film, and after the spraying is completed, the film is dried at 90-100 DEG C for 10-15 min to obtain a pretreated polyurethane adhesive film; Step three: the pretreated polyurethane adhesive film is immersed in a 0.2-0.3wt% polyethyleneimine solution for 3-5 min, dried, and then immersed in a 1.2-1.5wt% polyacrylic acid solution for 3-5 min to obtain a modified polyurethane adhesive film; The modified polyurethane adhesive film is immersed in a cationic solution for 3-5 min, dried, and then immersed in an anionic solution for 3-5 min, and after drying, the first surface assembly of the modified polyurethane adhesive film is completed; the surface assembly of the modified polyurethane adhesive film is repeated for 5-6 times to obtain a finished product.

2. The method for preparing a non-MOCA type fitness equipment coating material according to claim 1, characterized in that: In step one, 2,2-dimethylol propionic acid is dissolved in N-methyl pyrrolidone to obtain a 2,2-dimethylol propionic acid solution; the content of each component of the polyurethane emulsion is as follows: 40-50 parts of polytetrahydrofuran, 30-35 parts of isophorone diisocyanate, 6-8 parts of 1,4-butanediol, 8-10 parts of 2,2-dimethylol propionic acid, 15-20 parts of N-methyl pyrrolidone, 6-8 parts of hydroxyl chain extender, 3-4 parts of triethylamine, 130-150 parts of deionized water, and 8-10 parts of flame-retardant filler.

3. The method for preparing a non-MOCA type fitness equipment coating material according to claim 1, characterized in that: In step two, the mass-volume ratio of the flame-retardant filler and ethanol is 0.03g:(5-6)mL.

4. The method for preparing a non-MOCA type fitness equipment coating material according to claim 1, characterized in that: In step three, chitosan is dissolved in a 0.9-1.0wt% acetic acid solution to obtain a 1.0-1.2wt% chitosan solution; ammonium polyphosphate is added and dispersed in deionized water to obtain a 4.8-5.0wt% ammonium polyphosphate solution; and sodium hexametaphosphate is dissolved in deionized water to obtain a 1.3-1.5wt% sodium hexametaphosphate solution; The chitosan solution is added dropwise into the ammonium polyphosphate solution, and after the addition is completed, the mixture is allowed to stand for 3-5 min, and then centrifuged, washed and dried to obtain a chitosan coating; the chitosan coating is dissolved in a 0.9-1.0 wt% acetic acid solution to obtain a 1.5-1.7 wt% cationic solution; the sodium hexametaphosphate solution is added dropwise into the chitosan solution, and after the addition is completed, the mixture is allowed to stand for 3-5 min, and then centrifuged, washed and dried to obtain a sodium hexametaphosphate coating; the sodium hexametaphosphate coating is dissolved in deionized water to obtain a 1.5-1.7 wt% anionic solution; and the thickness of the finished encapsulating material is 3-4 mm.

5. The method for preparing a non-MOCA type fitness equipment coating material according to claim 1, characterized in that: The preparation process of the hydroxyl chain extender is as follows: diisopropanolamine and 4-formylphenylboronic acid are added to anhydrous methanol, stirred uniformly, and then reacted at 25-30°C in the dark for 45-50 h; after the reaction is completed, the product is centrifuged, washed and dried to obtain the hydroxyl chain extender.

6. The method for preparing a non-MOCA type fitness equipment coating material according to claim 5, characterized in that: The reaction molar ratio of diisopropanolamine to 4-formylphenylboronic acid is 1. (1.1-1.2)。 7. The method for preparing a non-MOCA type fitness equipment coating material according to claim 1, characterized in that: The preparation process of the flame-retardant filler is as follows: Step S1: γ-aminopropyltriethoxysilane is added to deionized water, and a 0.9-1.0 wt% acetic acid solution is added to adjust the pH to 3.0-3.5 to obtain a silane coupling agent solution; α-alumina is added to a mixture of ethanol and deionized water, and the mixture is ultrasonically dispersed uniformly, and then the silane coupling agent solution is added, and the mixture is refluxed at 80-85°C for 6-8 h; after the reaction is completed, the product is centrifuged, washed and dried to obtain pretreated alumina; Step S2: under a nitrogen atmosphere, hexachlorocyclotriphosphazene, triethylamine and pretreated alumina are added to tetrahydrofuran, and the mixture is ultrasonically dispersed uniformly to obtain a hexachlorocyclotriphosphazene solution, a triethylamine solution and a pretreated alumina solution, respectively; The triethylamine solution is slowly added to the hexachlorocyclotriphosphazene solution, and after the addition is completed, the temperature is raised to 60-65°C; then the pretreated alumina solution is added dropwise, and after the addition is completed, the reaction is continued for 10-12 h; after the reaction is completed, the product is filtered, washed, centrifuged, washed again, dried, ground and obtained to obtain the flame-retardant filler.

8. The method for preparing a non-MOCA type fitness equipment coating material according to claim 7, characterized in that: In step S1, the mass-volume ratio of γ-aminopropyltriethoxysilane to deionized water in the silane coupling agent solution is 0.3 g:(8-9) mL; and in the preparation of the pretreated alumina, the mass-volume ratio of α-alumina, the silane coupling agent solution, ethanol and deionized water is (4.0-4.5) g:4 mL:100 mL:100 mL.

9. A method for preparing a non-MOCA type fitness equipment coating material according to claim 7, characterized in that: In step S2, the reaction mass ratio of hexachlorocyclotriphosphazene, triethylamine and pretreated alumina is 1.4:3:(9-10).

10. A non-MOCA type fitness equipment encapsulant material characterized by, Prepared according to the preparation method of any one of claims 1-9.