Silicon-based flame-retardant waterborne polyurethane ultra-fine fiber and preparation method thereof

Abstract

The present invention provides a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber and a preparation method thereof, and belongs to the technical field of polymer materials. The present invention first hydrolyzes a silicon source under alkaline conditions to obtain silicon dioxide nanospheres, then performs silane modification on the nanospheres, and couples and modifies different phosphorus-containing compounds on the nanospheres to obtain phosphorus-hybridized silicon-based flame retardants. Then, the nanospheres are mixed with isophorone diisocyanate, polytetrahydrofuran diol, dibutyltin dilaurate and dihydroxymethyl propionic acid and the silicon-based flame retardant to obtain a prepolymer, and the prepolymer is emulsified in a dispersant to obtain a silicon-based flame retardant / polyurethane emulsion, and then a certain amount of thickener, defoamer, leveling agent, color paste, etc. are added, and then the coating is laminated with the base cloth, matured, and peeled off to obtain the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber. The silicon-based flame-retardant waterborne polyurethane of the present invention achieves excellent mechanical and flame-retardant properties, and at the same time has excellent smoke suppression and low toxicity effects.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber and a preparation method thereof. Background Art

[0002] At present, polyurethane microfiber materials have broad application prospects. In actual practice, they are widely used in clothing, home furnishings, automotive interiors and other fields. However, there are relatively few studies on flame-retardant waterborne polyurethane microfibers. Most existing polyurethane microfiber materials have poor flame retardancy and are easy to burn and cause safety hazards when encountering open flames. Therefore, flame retardants and flame-retardant polyurethane microfibers can play an important role in reducing the loss of life and property caused by fire.

[0003] According to the different methods of introducing flame retardant elements, flame retardants can be divided into additive type and reactive type. Additive flame retardants are directly mixed with polyurethane materials by physical blending without participating in chemical reactions, but there are interfacial effects and poor compatibility, which affects the mechanical properties of flame-retardant polyurethane composite materials; reactive flame retardants are introduced into waterborne polyurethane matrix by chemical reactions to form a flame-retardant polyurethane composite material, thereby imparting certain flame retardancy.

[0004] In addition, according to the type of flame retardant elements, they can be divided into halogen, nitrogen, phosphorus, silicon, phosphorus-halogen synergistic flame retardants, phosphorus-nitrogen synergistic flame retardants, etc. Among them, phosphorus flame retardants and phosphorus-halogen synergistic flame retardants are widely studied and applied, and they mainly play a role in the gas phase and condensed phase. The release of phosphorus-containing free radicals in the gas phase interrupts the combustion chain reaction and absorbs heat to increase the difficulty of ignition of the system. Phosphorus-nitrogen flame retardants are thermally decomposed to produce inert gases to dilute the combustible gas and oxygen concentration to terminate combustion. In polymers, phosphorus-containing flame retardants are thermally decomposed to produce phosphates, etc., and phosphorus-silicon flame retardants also produce a silicon dioxide carbon layer. The non-combustible solid substance wraps the surface of the material to isolate oxygen and heat transfer, achieving a flame retardant effect.

[0005] In addition, the flame retardant effect of a single flame retardant system is limited. At the same time, increasing the content of the flame retardant system will affect the mechanical properties of the polyurethane ultra-fiber to a certain extent. Therefore, there is an urgent need for a polyurethane ultra-fiber material that can ensure excellent mechanical properties, flame retardant properties, smoke suppression and low toxicity. Summary of the invention

[0006] The purpose of the present invention is to provide a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber and a preparation method thereof, which are used to solve the technical problems that the flame retardant effect of a single flame retardant system is limited and the flame retardant and mechanical properties of the polyurethane ultra-fine fiber cannot be achieved at the same time.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber, comprising the following steps:

[0009] (1) Tetraethyl silicate is dispersed in anhydrous ethanol, and ammonia water is added to carry out a hydrolysis reaction under alkaline conditions to obtain silica nanospheres. A silane coupling agent is then added to carry out a reflux reaction, and powder A1 is obtained after solid-liquid separation and drying;

[0010] (2) Dispersing phosphite, alcohol amine and paraformaldehyde in chloroform for reaction, and separating by rotary evaporation to obtain a yellow viscous substance A2;

[0011] (3) Powder A1 is dispersed in anhydrous ethanol, and then yellow viscous substance A2 and ammonium polyphosphate are added in sequence for reaction. After the reaction is completed, solid-liquid separation and drying are performed to obtain powder A3;

[0012] (4) isophorone diisocyanate, polytetramethylene glycol and dibutyltin dilaurate are mixed and subjected to a prepolymerization reaction, and then dimethylolpropionic acid and powder A3 are added and mixed to obtain a prepolymer; the prepolymer is emulsified in a dispersant aqueous solution to obtain an emulsion A4;

[0013] (5) Emulsion A4, thickener, defoamer, leveling agent and color paste are mixed, and the resulting mixture is coated with a base cloth, aged, and peeled off to obtain a silicone-based flame-retardant waterborne polyurethane microfiber.

[0014] Furthermore, the silane coupling agent contains triaminopropyltriethoxysilane; the mass ratio of tetraethyl silicate, anhydrous ethanol, ammonia water and silane coupling agent is 1:10~30:0.1~1.0:0.1~1.0.

[0015] Furthermore, the temperature of the reflux reaction is 80-90° C., and the time of the reflux reaction is 8-10 h.

[0016] Furthermore, the phosphite comprises one or more of trimethyl phosphite, triethyl phosphite, diethyl phosphite and triphenyl phosphite; the alcohol amine comprises one or more of monoethanolamine, diethanolamine and triethanolamine; and the mass ratio of the phosphite, alcohol amine, paraformaldehyde and chloroform is 1:0.5~2.0:0.1~1.0:20~30.

[0017] Furthermore, in step (2), the reaction temperature is 40-60° C., and the reaction time is 8-12 h.

[0018] Furthermore, in step (3), the mass ratio of powder A1, yellow viscous substance A2, ammonium polyphosphate and anhydrous ethanol is 1:10~50:10~30:50~100;

[0019] The reaction temperature is 40-60° C., and the reaction time is 3-6 hours.

[0020] Furthermore, the mass ratio of isophorone diisocyanate, polytetramethylene glycol, dibutyltin dilaurate, dimethylolpropionic acid and powder A3 is 1:1~10:0.5~5:0.1~0.5:0.1~1.0;

[0021] The mass ratio of the prepolymer to the dispersant aqueous solution is 1:3-5; the dispersant aqueous solution is a sodium hexametaphosphate aqueous solution; and the mass ratio of the dispersant to water in the dispersant aqueous solution is 1:0.1-1.0.

[0022] Furthermore, in the step (4), the prepolymerization temperature is 80-90° C., and the prepolymerization time is 0.5-3 h; the emulsification treatment is carried out in a high-speed emulsifier at a rotation speed of 1000-2000 rpm, and the emulsification treatment time is 1.5-3 h.

[0023] Furthermore, the mass ratio of the emulsion A4, the thickener, the defoamer, the leveling agent and the color paste is 1: 0.01~0.05: 0.01~0.03: 0.01~0.03: 0.03~0.08.

[0024] The invention also provides a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber.

[0025] Beneficial effects of the present invention:

[0026] 1. In the silicon-based flame-retardant waterborne polyurethane ultra-fiber of the present invention, the silicon dioxide nanospheres form hydrogen bonds and chemical bonds with the waterborne polyurethane, thereby improving its mechanical properties and stability;

[0027] 2. In the silicon-based flame-retardant water-based polyurethane ultra-fine fiber described in the present invention, the silicon-based flame retardant has three flame-retardant elements, namely phosphorus, nitrogen and silicon, and can produce a phosphorus-nitrogen-silicon synergistic flame-retardant effect. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber, comprising the following steps:

[0029] (1) Tetraethyl silicate is dispersed in anhydrous ethanol, and ammonia water is added to carry out a hydrolysis reaction under alkaline conditions to obtain silica nanospheres. A silane coupling agent is then added to carry out a reflux reaction, and powder A1 is obtained after solid-liquid separation and drying;

[0030] (2) Dispersing phosphite, alcohol amine and paraformaldehyde in chloroform for reaction, and separating by rotary evaporation to obtain a yellow viscous substance A2;

[0031] (3) Powder A1 is dispersed in anhydrous ethanol, and then yellow viscous substance A2 and ammonium polyphosphate are added in sequence for reaction. After the reaction is completed, solid-liquid separation and drying are performed to obtain powder A3;

[0032] (4) isophorone diisocyanate, polytetramethylene glycol and dibutyltin dilaurate are mixed and subjected to a prepolymerization reaction, and then dimethylolpropionic acid and powder A3 are added and mixed to obtain a prepolymer; the prepolymer is emulsified in a dispersant aqueous solution to obtain an emulsion A4;

[0033] (5) Emulsion A4, thickener, defoamer, leveling agent and color paste are mixed, and the resulting mixture is coated with a base cloth, aged, and peeled off to obtain a silicone-based flame-retardant waterborne polyurethane microfiber.

[0034] In the present invention, in step (1), the hydrolysis reaction time is 4 to 6 hours, preferably 6 hours.

[0035] In the present invention, the silane coupling agent is preferably triaminopropyltriethoxysilane; the mass ratio of tetraethyl silicate, anhydrous ethanol, ammonia water and silane coupling agent is 1:10~30:0.1~1.0:0.1~1.0, preferably 1:15~25:0.2~0.8:0.2~0.8, and further preferably 1:18~22:0.4~0.6:0.4~0.6.

[0036] In the present invention, the temperature of the reflux reaction is 80-90° C., preferably 82-88° C., and more preferably 85° C.; the time of the reflux reaction is 8-10 h, and preferably 9 h.

[0037] In the present invention, the phosphite comprises one or more of trimethyl phosphite, triethyl phosphite, diethyl phosphite and triphenyl phosphite, preferably one or more of trimethyl phosphite, triethyl phosphite and diethyl phosphite; the alcohol amine comprises one or more of monoethanolamine, diethanolamine and triethanolamine, preferably monoethanolamine and / or diethanolamine; the mass ratio of the phosphite, alcohol amine, paraformaldehyde and chloroform is 1:0.5~2.0:0.1~1.0:20~30, preferably 1:0.8~1.5:0.2~0.8:22~28, and more preferably 1:1.0~1.2:0.4~0.6:23~26.

[0038] In the present invention, in step (2), the reaction temperature is 40-60°C, preferably 45-55°C, and more preferably 50°C; the reaction time is 8-12h, preferably 9-11h, and more preferably 10h.

[0039] In the present invention, in step (3), the mass ratio of powder A1, yellow viscous substance A2, ammonium polyphosphate and anhydrous ethanol is 1:10-50:10-30:50-100, preferably 1:20-40:15-25:60-90, and more preferably 1:25-35:18-22:70-80.

[0040] In the present invention, the reaction temperature is 40-60° C., preferably 45-55° C., and more preferably 50° C.; the reaction time is 3-6 h, and preferably 4-5 h.

[0041] In the present invention, the mass ratio of isophorone diisocyanate, polytetramethylene glycol, dibutyltin dilaurate, dimethylolpropionic acid and powder A3 is 1:1~10:0.5~5:0.1~0.5:0.1~1.0, preferably 1:2~8:1~4:0.2~0.4:0.2~0.8, and further preferably 1:3~7:2~3:0.3~0.35:0.3~0.7.

[0042] In the present invention, the mass ratio of the prepolymer to the dispersant aqueous solution is 1:3~5, preferably 1:4; the dispersant aqueous solution is a sodium hexametaphosphate aqueous solution; the mass ratio of the dispersant to water in the dispersant aqueous solution is 1:0.1~1.0, preferably 1:0.2~0.8, and further preferably 1:0.3~0.7.

[0043] In the present invention, in the step (4), the temperature of the prepolymerization reaction is 80-90°C, preferably 82-88°C, and more preferably 85°C; the time of the prepolymerization reaction is 0.5-3h, preferably 1-2h, and more preferably 1.5h; the emulsification treatment is carried out in a high-speed emulsifier at a rotation speed of 1000-2000rpm, preferably 1000rpm; the time of the emulsification treatment is 1.5-3h, and preferably 2h.

[0044] In the present invention, the mass ratio of the emulsion A4, thickener, defoamer, leveling agent and color paste is 1: 0.01~0.05: 0.01~0.03: 0.01~0.03: 0.03~0.08, preferably 1: 0.02~0.04: 0.02~0.03: 0.02~0.03: 0.04~0.07, and further preferably 1: 0.03~0.04: 0.02: 0.02: 0.04~0.06.

[0045] In the present invention, the thickener, defoamer, leveling agent and color paste are all industrial products, and there is no special limitation on the types.

[0046] In the present invention, the silicon dioxide nanospheres have the advantages of high specific surface area, porosity, expansion coefficient and low density, etc. The silicon dioxide nanospheres form hydrogen bonds with oxygen atoms, nitrogen atoms and the like in the waterborne polyurethane microfiber matrix, and at the same time, isocyanate groups react with silanol groups to produce covalent bonds such as urethane bonds to connect polyurethane and silicon dioxide, and the formation of such covalent bonds can greatly improve the bonding strength between polyurethane and silicon dioxide nanospheres, so that the composite material has excellent mechanical properties and stability. At the same time, after coupling with phosphorus-containing compounds, the silicon dioxide nanospheres have phosphorus, nitrogen and silicon elements, which can form a phosphorus-nitrogen-silicon synergistic flame retardant effect.

[0047] The invention also provides a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber.

[0048] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] (1) At 30°C, 10.0 g of tetraethyl silicate was dispersed in 200.0 g of anhydrous ethanol, and 5.0 g of concentrated aqueous ammonia was added. The mixture was hydrolyzed for 6 h, and then 2.0 g of triaminopropyltriethoxysilane was added. The temperature was raised to 80°C and refluxed for 10.0 h. After the reaction was completed, powder A1 was obtained after solid-liquid separation.

[0051] (2) Disperse 2.0 g of trimethyl phosphite, 2.0 g of triethanolamine and 0.5 g of paraformaldehyde in 50.0 g of chloroform, and continue the reaction at 55 °C for 12.0 h. After removing the solvent by rotary evaporation, a yellow viscous substance A2 can be obtained;

[0052] (3) Disperse 2.0 g of powder A1 in 150.0 g of anhydrous ethanol, then add 30.0 g of yellow viscous substance A2 and stir at 50 °C for 2.0 h. Then add 20.0 g of ammonium polyphosphate and continue the reaction for 5.0 h. After solid-liquid separation, powder A3 can be obtained.

[0053] (4) 22.2 g of isophorone diisocyanate, 60.0 g of polytetramethylene glycol, and 18.0 g of dibutyltin dilaurate were prepolymerized at 85°C for 2.0 h, and then 3.0 g of dihydroxymethylpropionic acid and 1.0 g of A3 were added and mixed evenly to obtain a prepolymer. The prepolymer was then dispersed in 300.0 g of a 0.3% sodium hexametaphosphate aqueous solution and emulsified at 1000 rpm for 1.5 h to obtain emulsion A4.

[0054] (5) Finally, 3.0 g thickener, 1.0 g defoamer, 1.0 g leveling agent and 6.0 g color paste were added to the emulsion A4 and stirred evenly. The obtained emulsion was then scraped onto the surface of the flat paper and pre-baked at 100°C for 5 min to obtain a coating. The emulsion was laminated with a microfiber needle-punched non-woven fabric at 100°C for 90 s and aged at 120°C for 8 min to obtain a silicone-based flame-retardant waterborne polyurethane microfiber leather.

[0055] Example 2

[0056] The same as Example 1, except that 2.0 g of powder A3 is added in step (4).

[0057] Example 3

[0058] The same as Example 1, except that 3.0 g of powder A3 is added in step (4).

[0059] Example 4

[0060] The same as Example 1, except that 4.0 g of powder A3 is added in step (4).

[0061] Example 5

[0062] The same as Example 1, except that 5.0 g of powder A3 is added in step (4).

[0063] Comparative Example 1

[0064] The same as Example 1, except for step (4) and step (5):

[0065] (4) 22.2 g of isophorone diisocyanate, 60.0 g of polytetramethylene glycol, and 18.0 g of dibutyltin dilaurate were prepolymerized at 85°C for 2.0 h, and then 3.0 g of dimethylolpropionic acid was added and mixed evenly to obtain a prepolymer. The prepolymer was then dispersed in 300.0 g of a 0.3% sodium hexametaphosphate aqueous solution and emulsified at 1000 rpm for 1.5 h to obtain emulsion A4.

[0066] (5) Finally, 3.0 g thickener, 1.0 g defoamer, 1.0 g leveling agent and 6.0 g color paste were added to the emulsion A4 and stirred evenly. The obtained emulsion was then scraped onto the surface of the flat paper and pre-baked at 100°C for 5 min to obtain a coating. The emulsion was laminated with a microfiber needle-punched non-woven fabric at 100°C for 90 s and aged at 120°C for 8 min to obtain a silicone-based flame-retardant waterborne polyurethane microfiber leather.

[0067] The flame retardant properties of the silicon-based flame retardant waterborne polyurethane microfiber leathers prepared in Examples 1-5 and Comparative Examples were tested, and the results are shown in Table 1. The flame retardant test standards refer to GB / T 5455-1997 "Vertical method for testing the burning performance of textiles" and GBT 5454-1997 "Oxygen index method for testing the burning performance of textiles".

[0068] Table 1 Test results of flame retardant and tensile properties of silicone-based flame retardant waterborne polyurethane microfiber leather

[0069]

[0070] From Examples 1 to 5, the comparative examples and the corresponding test tables, it can be concluded that the waterborne polyurethane ultra-fine leather composite material prepared by adding a silicon-based flame retardant can meet the flame retardant V-0 grade requirements, and the flame retardant level can basically meet various application scenarios. At the same time, the tensile strength of the composite material is also enhanced, indicating that the silicon-based flame retardant material and the waterborne polyurethane form a strong bonding effect.

[0071] As can be seen from the above embodiments, the present invention provides a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber and a preparation method thereof. The present invention first hydrolyzes a silicon source under alkaline conditions to obtain silicon dioxide nanospheres, then performs silane modification on the nanospheres, and couples and modifies different phosphorus-containing compounds on the nanospheres to obtain phosphorus-hybridized silicon-based flame retardants. Then, the nanospheres are mixed with isophorone diisocyanate, polytetrahydrofuran diol, dibutyltin dilaurate and dihydroxymethyl propionic acid and silicon-based flame retardants to obtain prepolymers, and the prepolymers are emulsified in a dispersant to obtain silicon-based flame retardant / polyurethane emulsions, and then a certain amount of thickeners, defoamers, leveling agents, color pastes, etc. are added, and then the coating is laminated with the base cloth, matured, and peeled off to obtain silicon-based flame-retardant waterborne polyurethane ultra-fine fibers. The silicon-based flame-retardant waterborne polyurethane of the present invention achieves excellent mechanical and flame-retardant properties, and at the same time has excellent smoke suppression and low toxicity effects.

[0072] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for preparing a silicon-based flame-retardant waterborne polyurethane ultra-fine fiber, characterized in that: The following steps are involved: (1) Tetraethyl silicate is dispersed in anhydrous ethanol, and ammonia water is added to carry out a hydrolysis reaction under alkaline conditions to obtain silica nanospheres. A silane coupling agent is then added to carry out a reflux reaction, and powder A1 is obtained after solid-liquid separation and drying; (2) Dispersing phosphite, alcohol amine and paraformaldehyde in chloroform for reaction, and separating by rotary evaporation to obtain a yellow viscous substance A2; (3) Powder A1 is dispersed in anhydrous ethanol, and then yellow viscous substance A2 and ammonium polyphosphate are added in sequence for reaction. After the reaction is completed, solid-liquid separation and drying are performed to obtain powder A3; (4) isophorone diisocyanate, polytetramethylene glycol and dibutyltin dilaurate are mixed and subjected to a prepolymerization reaction, and then dimethylolpropionic acid and powder A3 are added and mixed to obtain a prepolymer; the prepolymer is emulsified in a dispersant aqueous solution to obtain an emulsion A4; (5) Emulsion A4, thickener, defoamer, leveling agent and color paste are mixed, and the resulting mixture is coated with a base cloth, aged, and peeled off to obtain a silicone-based flame-retardant waterborne polyurethane microfiber.

2. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 1, characterized in that: The silane coupling agent contains triaminopropyltriethoxysilane; the mass ratio of tetraethyl silicate, anhydrous ethanol, ammonia water and silane coupling agent is 1:10-30:0.1-1.0:0.1-1.

0.

3. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 1 or 2, characterized in that: The temperature of the reflux reaction is 80-90° C., and the time of the reflux reaction is 8-10 hours.

4. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 3, characterized in that: The phosphite comprises one or more of trimethyl phosphite, triethyl phosphite, diethyl phosphite and triphenyl phosphite; the alcohol amine comprises one or more of monoethanolamine, diethanolamine and triethanolamine; the mass ratio of the phosphite, alcohol amine, paraformaldehyde and chloroform is 1:0.5~2.0:0.1~1.0:20~30.

5. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 1, 2 or 4, characterized in that: In the step (2), the reaction temperature is 40-60° C. and the reaction time is 8-12 h.

6. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 5, characterized in that: In the step (3), the mass ratio of powder A1, yellow viscous substance A2, ammonium polyphosphate and anhydrous ethanol is 1:10-50:10-30:50-100; The reaction temperature is 40-60° C., and the reaction time is 3-6 hours.

7. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 6, characterized in that: The mass ratio of isophorone diisocyanate, polytetramethylene glycol, dibutyltin dilaurate, dimethylolpropionic acid and powder A3 is 1:1-10:0.5-5:0.1-0.5:0.1-1.0; The mass ratio of the prepolymer to the dispersant aqueous solution is 1:3-5; the dispersant aqueous solution is a sodium hexametaphosphate aqueous solution; and the mass ratio of the dispersant to water in the dispersant aqueous solution is 1:0.1-1.

0.

8. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 1 or 7, characterized in that: In the step (4), the prepolymerization reaction temperature is 80-90° C., and the prepolymerization reaction time is 0.5-3 h. The emulsification treatment is carried out in a high-speed emulsifier at a rotation speed of 1000-2000 rpm, and the emulsification treatment time is 1.5-3 h.

9. The method for preparing the silicon-based flame-retardant waterborne polyurethane ultra-fine fiber according to claim 8, characterized in that: The mass ratio of the emulsion A4, thickener, defoamer, leveling agent and color paste is 1: 0.01-0.05: 0.01-0.03: 0.01-0.03: 0.03-0.

08.

10. The silicon-based flame-retardant waterborne polyurethane superfiber prepared by the preparation method of the silicon-based flame-retardant waterborne polyurethane superfiber according to any one of claims 1 to 9.

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