阅读说明：本技术 一种阻燃型水性聚氨酯材料 (Flame-retardant waterborne polyurethane material ) 是由 陈海燕 束影 徐洁 蔡耿焘 于 2021-09-22 设计创作，主要内容包括：本案涉及一种阻燃型水性聚氨酯材料,包括复合阻燃剂和聚氨酯；所述复合阻燃剂为凹凸棒土复合材料,包括阴离子改性凹凸棒土、阳离子改性凹凸棒土和改性纳米蒙脱土；所述阴离子改性凹凸棒土是先对酸化后的凹凸棒土接枝KH-570,随后聚合不饱和烯基磺酸化合物而得；所述阳离子改性凹凸棒土是通过二氯磷酸苯酯的氯取代反应在酸化后的凹凸棒土上引入不饱和双键,随后与不饱和烯基氯化铵化合物聚合而得。本发明通过对凹凸棒土的分步改性,使得凹凸棒土具有良好的阻燃性和自身易分散性,通过电性相吸和空间位阻效应,在涂料体系中能够稳定分散；改性纳米蒙脱土粉具有协同作用,进一步提高与聚氨酯乳液体系的相容稳定性,提高涂料的韧性。(The scheme relates to a flame-retardant waterborne polyurethane material which comprises a composite flame retardant and polyurethane; the composite flame retardant is an attapulgite composite material and comprises anion modified attapulgite, cation modified attapulgite and modified nano montmorillonite; the anion modified attapulgite is obtained by grafting KH-570 on acidified attapulgite and then polymerizing an unsaturated alkenyl sulfonic acid compound; the cation modified attapulgite is obtained by introducing unsaturated double bonds into acidified attapulgite through a chlorine substitution reaction of phenyl dichlorophosphate and then polymerizing the unsaturated double bonds with an unsaturated alkenyl ammonium chloride compound. The attapulgite has good flame retardance and self-dispersibility by stepwise modification of the attapulgite, and can be stably dispersed in a coating system by electric attraction and steric hindrance effect; the modified nano montmorillonite powder has a synergistic effect, further improves the compatibility stability with a polyurethane emulsion system, and improves the toughness of the coating.)

1. The flame-retardant waterborne polyurethane material is characterized by comprising a composite flame retardant and polyurethane; the composite flame retardant is an attapulgite composite material and comprises anion modified attapulgite, cation modified attapulgite and modified nano montmorillonite;

the anion modified attapulgite is obtained by grafting KH-570 on acidified attapulgite and then polymerizing an unsaturated alkenyl sulfonic acid compound;

the cation modified attapulgite is obtained by introducing unsaturated double bonds into acidified attapulgite through a chlorine substitution reaction of phenyl dichlorophosphate and then polymerizing the unsaturated double bonds with an unsaturated alkenyl ammonium chloride compound;

the preparation process of the polyurethane comprises the following steps: adding 10-35% of PEG-2000, 7-13% of dimethylolpropionic acid, 1-2% of ethylene glycol chain extender and 1-5% of N-methyl pyrrolidone into a reaction bottle in percentage by mass, heating to 50 ℃, stirring for 1h, then adding 8-18% of 2, 4-toluene diisocyanate, heating to 80 ℃, and reacting for 90 min; then adding 4-5% of poly (ethylene glycol propylene glycol adipate) glycol, continuing stirring and reacting for 60min, cooling to below 50 ℃, adding DMF (dimethyl formamide) to adjust the viscosity of the system, and finally adding water for rapid emulsification to ensure that the solid content of the system is 30-40%.

2. The flame retardant polyurethane foam according to claim 1, wherein the anion modified attapulgite is prepared by a process comprising: adding acidified attapulgite into ethanol for ultrasonic treatment, then adding KH-570 with equal mass, stirring and dispersing uniformly, then heating to 60-70 ℃, and stirring and reacting for 4-5 h; centrifuging, washing with ethanol, collecting solid, and drying to obtain solid A; adding the collected solid A into a reaction bottle, sequentially adding ammonium persulfate, sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an unsaturated alkenyl sulfonic acid compound aqueous solution under stirring, and continuously stirring for reacting for 4-5h after dropwise adding; dialyzing, freezing and drying to obtain the corresponding anion modified attapulgite.

3. The flame-retardant, aqueous polyurethane material according to claim 2, wherein the unsaturated alkenyl sulfonic acid compound is one selected from the group consisting of vinyl sulfonic acid, allyl sulfonic acid, p-styrene sulfonic acid, 2-acrylamido dodecyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 2-acrylamido-n-butyl sulfonic acid.

4. The flame retardant polyurethane foam according to claim 1, wherein the cationically modified attapulgite is prepared by: adding phenyl dichlorophosphate and acetone into a reaction bottle, placing the reaction bottle in an ice-water bath, introducing nitrogen, blowing for 30min, adding triethylamine, dropwise adding hydroxyethyl methacrylate, and stirring for reacting for 4 h; the reaction bottle is moved to room temperature and is continuously stirred for 30 min; then adding a certain amount of acidified attapulgite, stirring for 24h, washing with water, filtering, and drying to obtain a solid B; adding the collected solid B into a reaction bottle, sequentially adding ammonium persulfate, sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an unsaturated alkenyl ammonium chloride compound under stirring, and continuously stirring for reacting for 4-5h after dropwise adding; dialyzing, freezing and drying to obtain the corresponding anion modified attapulgite.

5. The flame-retardant aqueous polyurethane material according to claim 4, wherein the charge molar ratio of phenyl dichlorophosphate to hydroxyethyl methacrylate is 1: 1; the mass of the acidified attapulgite is 2.5-5% of the total mass of phenyl dichlorophosphate and hydroxyethyl methacrylate; the molar weight of triethylamine is 2.5 times that of phenyl dichlorophosphate.

6. The flame-retardant aqueous polyurethane material according to claim 4, wherein the unsaturated alkenyl ammonium chloride compound is one selected from the group consisting of allyl trimethyl ammonium chloride, (3-acrylamidopropyl) trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride and acryloyloxyethyl trimethyl ammonium chloride.

7. The flame retardant polyurethane foam of claim 1, wherein the modified nano-montmorillonite is prepared as follows: taking montmorillonite, drying in vacuum, grinding to obtain powder, taking a proper amount of powder, ultrasonically dispersing in deionized water, then adding hexadecyl trimethyl ammonium chloride with the mass of 1% of the powder, ultrasonically dispersing uniformly, continuously stirring for 12 hours at 60 ℃, then drying in vacuum, crushing and sieving; adding 10-20 wt% of zinc oxide nanoparticles, 5-15 wt% of stannic chloride nanoparticles and 10-15 wt% of silicon dioxide nanoparticles into the sieved powder to enable the total mass of the three nanoparticles to be 50% of the mass of the sieved powder, and then carrying out melt blending, tabletting and granulation to obtain mixed powder; adding phenolic resin into the mixed powder, fully mixing, tabletting, and pulverizing with an airflow pulverizer.

8. The flame retardant polyurethane foam of claim 1, wherein the attapulgite composite is prepared by:

dispersing 2-5 parts of modified nano montmorillonite powder in 100 parts of water, adding 0.1-0.5 part of methacryloyl ethyl sulfobetaine, performing ultrasonic treatment to uniformly disperse the modified nano montmorillonite powder, adding 10-10 parts of anion modified attapulgite and 10-15 parts of cation modified attapulgite, performing ultrasonic treatment for 1 hour, and then stirring at room temperature for 3 hours; and (5) standing for 12h after stirring, filtering, washing and drying to obtain the product.

9. The flame-retardant aqueous polyurethane material according to claim 1, further comprising an antifoaming agent, an anti-settling agent, a film-forming aid, a thickener, a leveling agent and water.

Technical Field

The invention relates to the technical field of polyurethane, in particular to a flame-retardant waterborne polyurethane material.

Background

Polyurethane resin is a polymer material which is widely used, and has the figure of polyurethane in the fields of paint, adhesive, textile and the like. Aqueous polyurethane dispersions are receiving increasing attention due to the ever stricter environmental requirements, which require the use of minimum amounts of volatile organic solvents. The waterborne polyurethane takes water as a solvent, and has the advantages of no pollution, safety, reliability, good mechanical property and the like. However, with the development of industrialization and the improvement of living standard, people pay more attention to the multifunctional performance of products, such as flame-retardant architectural coatings and flame-retardant finishing coatings, which are favored by consumers.

In order to achieve flame retardant performance of products, halogen-containing flame retardant substances are generally added into material systems, and although the flame retardant effect of the halogen-containing flame retardant substances is good, excessive halogen generates harmful substances which are difficult to degrade, so that the environment is polluted. And although the flame retardant performance can be improved by adding excessive flame retardant, the defects exist, especially in a water-based polyurethane system, the excessive flame retardant has poor compatibility with a base material, is easy to dissociate from the surface of the coating, and influences the formation of the coating.

Disclosure of Invention

Aiming at the defects in the prior art, the flame retardance and self-dispersibility of the modified attapulgite are improved by the modified attapulgite, so that the modified attapulgite is used for preparing flame-retardant waterborne polyurethane.

In order to achieve the purpose, the invention provides the following technical scheme:

a flame-retardant waterborne polyurethane material comprises a composite flame retardant and polyurethane; the composite flame retardant is an attapulgite composite material and comprises anion modified attapulgite, cation modified attapulgite and modified nano montmorillonite;

the anion modified attapulgite is obtained by grafting KH-570 on acidified attapulgite and then polymerizing an unsaturated alkenyl sulfonic acid compound;

the cation modified attapulgite is obtained by introducing unsaturated double bonds into acidified attapulgite through a chlorine substitution reaction of phenyl dichlorophosphate and then polymerizing the unsaturated double bonds with an unsaturated alkenyl ammonium chloride compound;

the preparation process of the polyurethane comprises the following steps: adding 10-35% of PEG-2000, 7-13% of dimethylolpropionic acid, 1-2% of ethylene glycol chain extender and 1-5% of N-methyl pyrrolidone into a reaction bottle in percentage by mass, heating to 50 ℃, stirring for 1h, then adding 8-18% of 2, 4-toluene diisocyanate, heating to 80 ℃, and reacting for 90 min; then adding 4-5% of poly (ethylene glycol propylene glycol adipate) glycol, continuing stirring and reacting for 60min, cooling to below 50 ℃, adding DMF (dimethyl formamide) to adjust the viscosity of the system, and finally adding water for rapid emulsification to ensure that the solid content of the system is 30-40%.

Further, the preparation process of the anion modified attapulgite comprises the following steps: adding acidified attapulgite into ethanol for ultrasonic treatment, then adding KH-570 with equal mass, stirring and dispersing uniformly, then heating to 60-70 ℃, and stirring and reacting for 4-5 h; centrifuging, washing with ethanol, collecting solid, and drying to obtain solid A; adding the collected solid A into a reaction bottle, sequentially adding ammonium persulfate, sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an unsaturated alkenyl sulfonic acid compound aqueous solution under stirring, and continuously stirring for reacting for 4-5h after dropwise adding; dialyzing, freezing and drying to obtain the corresponding anion modified attapulgite.

The anion modified attapulgite has excellent dispersibility compared with unmodified attapulgite. In the reaction process of the acidified attapulgite and the silane coupling agent (KH-570), crystal bundles gradually become smaller, and a KH-570 long-chain structure is introduced into the attapulgite, so that steric hindrance is increased, and a good dispersion state is shown. The terminal double bond of KH-570 has activity, and can increase the length of main chain by polymerizing with unsaturated anionic compound, and the anionic polymer chain contains sulfonic acid group and amide group, so that it can increase adsorption stability when used in coating system.

Further, the preparation process of the cation modified attapulgite comprises the following steps: adding phenyl dichlorophosphate and acetone into a reaction bottle, placing the reaction bottle in an ice-water bath, introducing nitrogen, blowing for 30min, adding triethylamine, dropwise adding hydroxyethyl methacrylate, and stirring for reacting for 4 h; the reaction bottle is moved to room temperature and is continuously stirred for 30 min; then adding a certain amount of acidified attapulgite, stirring for 24h, washing with water, filtering, and drying to obtain a solid B; adding the collected solid B into a reaction bottle, sequentially adding ammonium persulfate, sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an unsaturated alkenyl ammonium chloride compound under stirring, and continuously stirring for reacting for 4-5h after dropwise adding; dialyzing, freezing and drying to obtain the corresponding anion modified attapulgite.

According to the scheme, based on phenyl dichlorophosphate, attapulgite and HEA are grafted, a flame-retardant group containing double bonds and phosphorus is grafted on the surface of the attapulgite, and then the flame-retardant group is polymerized with an unsaturated cationic compound to form a network polymer chain on the surface of the attapulgite, so that a carbon layer with a compact structure is easily formed in the combustion process to cover the surface of a combustible substance, and the flame-retardant effect is achieved.

Further, the preparation of the modified nano montmorillonite is as follows: taking montmorillonite, drying in vacuum, grinding to obtain powder, taking a proper amount of powder, ultrasonically dispersing in deionized water, then adding hexadecyl trimethyl ammonium chloride with the mass of 1% of the powder, ultrasonically dispersing uniformly, continuously stirring for 12 hours at 60 ℃, then drying in vacuum, crushing and sieving; adding 10-20 wt% of zinc oxide nanoparticles, 5-15 wt% of stannic chloride nanoparticles and 10-15 wt% of silicon dioxide nanoparticles into the sieved powder to enable the total mass of the three nanoparticles to be 50% of the mass of the sieved powder, and then carrying out melt blending, tabletting and granulation to obtain mixed powder; and adding 100 wt% of phenolic resin into the mixed powder, fully mixing, tabletting and crushing by using an airflow crusher to obtain the phenolic resin tablet.

Further, the preparation of the attapulgite composite material is as follows:

dispersing 2-5 parts of modified nano montmorillonite powder in 100 parts of water, adding 0.1-0.5 part of methacryloyl ethyl sulfobetaine, performing ultrasonic treatment to uniformly disperse the modified nano montmorillonite powder, adding 10-10 parts of anion modified attapulgite and 10-15 parts of cation modified attapulgite, performing ultrasonic treatment for 1 hour, and then stirring at room temperature for 3 hours; and (5) standing for 12h after stirring, filtering, washing and drying to obtain the product.

The anion modified attapulgite and the cation modified attapulgite are attracted by positive and negative charges and then mixed with the zwitterion modified nano montmorillonite powder, and can be stably dispersed in a coating system through the mutual electric attraction and a certain steric hindrance effect.

Further, the unsaturated alkenyl sulfonic acid compound is selected from one of vinyl sulfonic acid, allyl sulfonic acid, p-styrene sulfonic acid, 2-acrylamido dodecyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 2-acrylamido-n-butyl sulfonic acid.

Further, the feeding molar ratio of the phenyl dichlorophosphate to the hydroxyethyl methacrylate is 1: 1; the mass of the acidified attapulgite is 2.5-5% of the total mass of phenyl dichlorophosphate and hydroxyethyl methacrylate; the molar weight of triethylamine is 2.5 times that of phenyl dichlorophosphate.

Further, the unsaturated alkenyl ammonium chloride compound is selected from one of allyl trimethyl ammonium chloride, (3-acrylamidopropyl) trimethyl ammonium chloride, methacryloxyethyl trimethyl ammonium chloride and acryloyloxyethyl trimethyl ammonium chloride.

Further comprises a defoaming agent, an anti-settling agent, a film forming auxiliary agent, a thickening agent, a leveling agent and water.

Compared with the prior art, the invention has the beneficial effects that: the attapulgite is used as a common filler in a coating system, and has good anti-settling and thickening effects in aqueous and solvent systems. But the attapulgite structure contains a large amount of flame retardant elements such as magnesium, aluminum and the like, so that the attapulgite has good heat insulation performance; according to the scheme, the attapulgite is modified step by step, so that the attapulgite has good flame retardance and self-dispersibility, and can be stably dispersed in a coating system through mutual electric attraction and a certain steric hindrance effect. The composite flame retardant also comprises modified nano montmorillonite powder, and after CTAB intercalation modification is utilized, zinc oxide, stannic chloride and silicon dioxide nano particles are used for melting and blending with montmorillonite modified by an organic intercalation, so that the nano particles enter between the montmorillonite layers, and the antibacterial performance of the composite material is further improved; finally, the nano particles are coated by the phenolic resin, so that the protective effect is further achieved, a semi-interpenetrating network structure is easily formed between the nano particles and the carboxyl-terminated polyurethane, the synergistic effect is achieved, the compatibility stability with a polyurethane emulsion system is further improved, and the toughness of the coating is improved; is beneficial to forming a coating which is flat, high in hardness and flame retardant.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The flame-retardant waterborne polyurethane material comprises 15 parts of composite flame retardant, 50 parts of polyurethane, 0.2 part of defoaming agent, 1 part of anti-settling agent, 3 parts of film-forming auxiliary agent, 0.3 part of thickening agent, 0.5 part of flatting agent and 30 parts of water.

The antifoaming agent and the thickening agent are purchased from Guangzhou Dachuan fine chemical engineering; the film-forming auxiliary agent is purchased from Nanjing chess to form a novel material; leveling agents are available from bibe, germany; the anti-settling agent is purchased from Guangzhou elegant innovative materials; the composite flame retardant and the polyurethane are prepared by the following preparation method, wherein the attapulgite in the used raw materials is purchased from macrologic mineral products factories in Ming City, Anhui province, and is activated by 2mol/L hydrochloric acid before use; montmorillonite is purchased from Zhejiang Fenghong clay chemical Co., Ltd; other drugs and reagents are commercially available, such as national drug group, alatin, mcelin, and the like.

Example 1:

the preparation process of the polyurethane comprises the following steps: adding 10% of PEG-2000, 7% of dimethylolpropionic acid, 1% of ethylene glycol chain extender and 1% of N-methylpyrrolidone into a reaction bottle, heating to 50 ℃, stirring for 1h, then adding 8-18% of 2, 4-toluene diisocyanate, heating to 80 ℃, and reacting for 90 min; then adding 4-5% of poly (ethylene glycol propylene glycol adipate) glycol, continuing stirring and reacting for 60min, cooling to below 50 ℃, adding DMF (dimethyl formamide) to adjust the viscosity of the system, and finally adding water for rapid emulsification to ensure that the solid content of the system is 30%.

The composite flame retardant comprises the following components:

s1: adding acidified attapulgite into ethanol for ultrasonic treatment, then adding KH-570 with equal mass, stirring and dispersing uniformly, then heating to 60-70 ℃, and stirring and reacting for 4-5 h; centrifuging, washing with ethanol, collecting solid, and drying to obtain solid A;

s2: adding 0.1mol of phenyl dichlorophosphate and 50ml of acetone into a reaction bottle, placing the reaction bottle in an ice-water bath, introducing nitrogen, blowing for 30min, adding 0.25mol of triethylamine, dropwise adding 0.1mol of hydroxyethyl methacrylate, and stirring for reacting for 4 h; the reaction bottle is moved to room temperature and is continuously stirred for 30 min; then adding 0.85g of acidified attapulgite, stirring for 24h, washing with water, filtering, and drying to obtain a solid B;

s3: adding 0.5g of the collected solid A0 to a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of p-styrene sulfonic acid under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain anion modified attapulgite;

s4: adding 0.5g of the collected solid B into a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of methacryloyloxyethyl trimethyl ammonium chloride under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain cation modified attapulgite;

s5: grinding montmorillonite after vacuum drying to obtain powder, ultrasonically dispersing 10g of the powder in deionized water, then adding 0.1g of hexadecyl trimethyl ammonium chloride, ultrasonically dispersing the mixture uniformly, continuously stirring the mixture for 12 hours at the temperature of 60 ℃, then vacuum drying, crushing and sieving the mixture; sequentially adding 1.5g of zinc oxide nano-particles, 1.1g of stannic chloride nano-particles and 1.3g of silicon dioxide nano-particles into the sieved powder, melting, blending, tabletting and granulating to obtain mixed powder; and adding 10g of phenolic resin into the mixed powder, fully mixing, tabletting and crushing by using an airflow crusher to obtain the modified nano montmorillonite powder.

S6: dispersing 1g of modified nano montmorillonite powder in 40ml of water, adding 0.01g of methacryloyl ethyl sulfobetaine, performing ultrasonic treatment to uniformly disperse the modified nano montmorillonite powder, adding 5g of anion modified attapulgite and 6g of cation modified attapulgite, continuing ultrasonic treatment for 1 hour, and then stirring at room temperature for 3 hours; and standing for 12 hours after stirring, filtering, washing and drying to obtain the attapulgite composite material, namely the composite flame retardant.

Example 2:

the preparation process of the polyurethane comprises the following steps: adding 15% of PEG-2000, 9% of dimethylolpropionic acid, 2% of ethylene glycol chain extender and 3% of N-methylpyrrolidone into a reaction bottle, heating to 50 ℃, stirring for 1h, then adding 10% of 2, 4-toluene diisocyanate, heating to 80 ℃, and reacting for 90 min; then adding 5% of polyethylene glycol propylene glycol adipate glycol, continuing stirring and reacting for 60min, cooling to below 50 ℃, adding DMF (dimethyl formamide) to adjust the viscosity of the system, and finally adding water to quickly emulsify to ensure that the solid content of the system is 35%.

The composite flame retardant comprises the following components:

s1: adding acidified attapulgite into ethanol for ultrasonic treatment, then adding KH-570 with equal mass, stirring and dispersing uniformly, then heating to 60-70 ℃, and stirring and reacting for 4-5 h; centrifuging, washing with ethanol, collecting solid, and drying to obtain solid A; adding 0.5g of the collected solid A0 to a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of 2-acrylamido dodecyl sulfonic acid under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain anion modified attapulgite;

s2: adding 0.1mol of phenyl dichlorophosphate and 50ml of acetone into a reaction bottle, placing the reaction bottle in an ice-water bath, introducing nitrogen, blowing for 30min, adding 0.25mol of triethylamine, dropwise adding 0.1mol of hydroxyethyl methacrylate, and stirring for reacting for 4 h; the reaction bottle is moved to room temperature and is continuously stirred for 30 min; then adding 0.85g of acidified attapulgite, stirring for 24h, washing with water, filtering, and drying to obtain a solid B; adding 0.5g of collected solid B into a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of allyl trimethyl ammonium chloride under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain cation modified attapulgite;

s3: grinding montmorillonite after vacuum drying to obtain powder, ultrasonically dispersing 10g of the powder in deionized water, then adding 0.1g of hexadecyl trimethyl ammonium chloride, ultrasonically dispersing the mixture uniformly, continuously stirring the mixture for 12 hours at the temperature of 60 ℃, then vacuum drying, crushing and sieving the mixture; sequentially adding 1.5g of zinc oxide nano-particles, 1.1g of stannic chloride nano-particles and 1.3g of silicon dioxide nano-particles into the sieved powder, melting, blending, tabletting and granulating to obtain mixed powder; and adding 10g of phenolic resin into the mixed powder, fully mixing, tabletting and crushing by using an airflow crusher to obtain the modified nano montmorillonite powder.

S4: dispersing 1g of modified nano montmorillonite powder in 40ml of water, adding 0.01g of methacryloyl ethyl sulfobetaine, performing ultrasonic treatment to uniformly disperse the modified nano montmorillonite powder, adding 5.5g of anion modified attapulgite and 5.5g of cation modified attapulgite, continuing ultrasonic treatment for 1 hour, and then stirring at room temperature for 3 hours; and standing for 12h after stirring, filtering, washing and drying to obtain the attapulgite composite material, namely the composite flame retardant.

Example 3:

the preparation process of the polyurethane comprises the following steps: adding 15% of PEG-2000, 9% of dimethylolpropionic acid, 2% of ethylene glycol chain extender and 3% of N-methylpyrrolidone into a reaction bottle, heating to 50 ℃, stirring for 1h, then adding 10% of 2, 4-toluene diisocyanate, heating to 80 ℃, and reacting for 90 min; then adding 5% of polyethylene glycol propylene glycol adipate glycol, continuing stirring and reacting for 60min, cooling to below 50 ℃, adding DMF (dimethyl formamide) to adjust the viscosity of the system, and finally adding water to quickly emulsify to ensure that the solid content of the system is 35%.

The composite flame retardant comprises the following components:

s1: adding acidified attapulgite into ethanol for ultrasonic treatment, then adding KH-570 with equal mass, stirring and dispersing uniformly, then heating to 60-70 ℃, and stirring and reacting for 4-5 h; centrifuging, washing with ethanol, collecting solid, and drying to obtain solid A; adding 0.25g of collected solid A0 to a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of vinyl sulfonic acid under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain anion modified attapulgite;

s2: adding 0.1mol of phenyl dichlorophosphate and 50ml of acetone into a reaction bottle, placing the reaction bottle in an ice-water bath, introducing nitrogen, blowing for 30min, adding 0.25mol of triethylamine, dropwise adding 0.1mol of hydroxyethyl methacrylate, and stirring for reacting for 4 h; the reaction bottle is moved to room temperature and is continuously stirred for 30 min; then adding 0.85g of acidified attapulgite, stirring for 24h, washing with water, filtering, and drying to obtain a solid B; adding 0.5g of collected solid B into a reaction bottle, sequentially adding 0.1g of ammonium persulfate, 0.05g of sodium bisulfite and water, uniformly stirring, heating to 60-70 ℃, slowly dropwise adding an aqueous solution containing 10g of acryloyloxyethyl trimethyl ammonium chloride under stirring, and continuously stirring for reacting for 4-5 hours after dropwise adding; dialyzing, freezing and drying to obtain cation modified attapulgite;

s3: grinding montmorillonite after vacuum drying to obtain powder, ultrasonically dispersing 10g of the powder in deionized water, then adding 0.1g of hexadecyl trimethyl ammonium chloride, ultrasonically dispersing the mixture uniformly, continuously stirring the mixture for 12 hours at the temperature of 60 ℃, then vacuum drying, crushing and sieving the mixture; sequentially adding 1.5g of zinc oxide nano-particles, 1.1g of stannic chloride nano-particles and 1.3g of silicon dioxide nano-particles into the sieved powder, melting, blending, tabletting and granulating to obtain mixed powder; and adding 10g of phenolic resin into the mixed powder, fully mixing, tabletting and crushing by using an airflow crusher to obtain the modified nano montmorillonite powder.

S4: dispersing 1g of modified nano montmorillonite powder in 40ml of water, adding 0.01g of methacryloyl ethyl sulfobetaine, performing ultrasonic treatment to uniformly disperse the modified nano montmorillonite powder, adding 6g of anion modified attapulgite and 6.5g of cation modified attapulgite, continuing ultrasonic treatment for 1 hour, and then stirring at room temperature for 3 hours; and standing for 12 hours after stirring, filtering, washing and drying to obtain the attapulgite composite material, namely the composite flame retardant.

The attapulgite composite material is used as a composite flame retardant to prepare a corresponding flame-retardant waterborne polyurethane material according to the composition.

Comparative example 1:

the same as example 1 except that the anion modified attapulgite was removed.

Comparative example 2:

the same as example 1 except that the cation-modified attapulgite was removed.

Comparative example 3:

the difference from example 1 is that the phenolic resin of the last step is removed when preparing the modified nano-montmorillonite.

Comparative example 4:

the flame-retardant waterborne polyurethane material comprises 15 parts of acidified attapulgite, 50 parts of polyurethane, 0.2 part of defoaming agent, 1 part of anti-settling agent, 3 parts of film-forming auxiliary agent, 0.3 part of thickening agent, 0.5 part of flatting agent and 30 parts of water.

50g of the flame-retardant polyurethane material is taken and respectively placed on the surface of a polytetrafluoroethylene plate for film paving, the polytetrafluoroethylene plate is naturally aired for 14 days, then the dried polytetrafluoroethylene plate is dried for 4 hours in a vacuum drying oven at 90 ℃, and the dried coating is tested, wherein the specific test results are shown in table 1.

Observing the appearance condition of the coating after standing for 24 hours; the oxygen index and physical properties were tested according to GB/T2406.2-2009, ASTM D412-1998 (2002).

TABLE 1

As can be seen from the data in Table 1, the polyurethane prepared by the invention is flame-retardant polyurethane, and the oxygen index is 32-34%; meanwhile, the stability of the coating is good, flocculation and sedimentation cannot occur, the toughness of the polyurethane material can be improved by compounding the attapulgite and the nano montmorillonite, the tensile strength and the bending degree are effectively improved, and the hardness of the polyurethane coating is moderate; the data of comparative example 4 are not shown in table 1, and the dispersibility of the attapulgite in the polyurethane system is poor and the auxiliary dispersant is not added in the system when the polyurethane material is prepared, so that the preparation process is not smooth and the uniformly dispersed coating cannot be obtained, and the subsequent performance test is not performed.

While embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments, which are fully applicable in all kinds of fields of application of the invention, and further modifications may readily be effected by those skilled in the art, so that the invention is not limited to the specific details without departing from the general concept defined by the claims and the scope of equivalents.