A flame-retardant shoe sole material and its preparation method

Abstract

This invention relates to the field of polyurethane shoe sole technology and discloses a flame-retardant shoe sole material and its preparation method. The flame-retardant shoe sole material of this invention comprises 100 parts by weight of polyester polyol, 3-10 parts by weight of flame-retardant modified montmorillonite, 5.2-6.4 parts by weight of chain extender, 18-27 parts by weight of foaming agent, and 113-124 parts by weight of isocyanate, etc. The DOPO amino hydrochloride-modified montmorillonite has better dispersibility and improved compatibility with polyurethane foam materials, thereby enhancing the mechanical properties and compressive strength of the polyurethane foam shoe sole material. Simultaneously, the DOPO amino hydrochloride contains the DOPO structure and multiple nitrogen elements, forming a nitrogen-phosphorus flame retardant, which forms a synergistic flame-retardant system with montmorillonite, enhancing the flame-retardant performance of the shoe sole material.

Description

Technical Field

[0001] This invention relates to the field of polyurethane shoe sole technology, specifically to a flame-retardant shoe sole material and its preparation method. Background Technology

[0002] The main materials for shoe soles include polyurethane, rubber, and EVA. Among them, polyurethane foam has good water resistance, high elasticity, and excellent shock resistance, making it important in footwear manufacturing, thermal insulation, and foaming adhesives. However, polyurethane foam soles have poor compressibility and are flammable, limiting their practical application in areas such as fire boots.

[0003] Adding nanomaterials to polyurethane foam can improve its mechanical properties. Montmorillonite is an inexpensive and readily available natural silicate nanomaterial with a large specific surface area, excellent mechanical properties, and certain synergistic flame-retardant properties, making it widely used. Modification of montmorillonite results in organomontmorillonite with good dispersibility and high compatibility with polymer materials, which is beneficial for improving material performance. Patent CN116041658B discloses a shock-absorbing material and its preparation method, using modified montmorillonite and fluorinated polyborosiloxane to improve the elasticity, cushioning, shock absorption, and hydrolysis resistance of polyurethane, making it suitable for manufacturing sports shoes. However, this polyurethane shock-absorbing material does not have good flame-retardant properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a flame-retardant shoe sole material and its preparation method, solving the problems of poor strength and flame retardancy in polyurethane shoe sole materials.

[0005] The technical solution of the present invention is: a flame-retardant shoe sole material and its preparation method, comprising 100 parts by weight of polyester polyol, 3-10 parts by weight of flame-retardant modified montmorillonite, 5.2-6.4 parts by weight of chain extender, 18-27 parts by weight of foaming agent, 2-6 parts by weight of foam leveling agent, 1.6-2.8 parts by weight of catalyst, 1.5-2.4 parts by weight of water, and 113-124 parts by weight of isocyanate substance.

[0006] The preparation method of flame-retardant shoe sole material is as follows:

[0007] (1) Add water and 100 parts by weight of montmorillonite to a flask, disperse ultrasonically for 1-1.5 h, then add 1,4-dioxane solvent and 80-180 parts by weight of DOPO amino hydrochloride, heat to 60-90℃, stir for 3-10 h, dry to remove solvent, and obtain flame retardant modified montmorillonite.

[0008] (2) The polyester polyol, flame retardant modified montmorillonite, chain extender, foaming agent, foam leveling agent, catalyst and water are stirred and mixed, and then quickly mixed with isocyanate material and added to mold for foaming and curing to obtain flame retardant shoe sole material.

[0009] Preferably, the chain extender includes 1,4-butanediol and triethanolamine.

[0010] Preferably, the isocyanate substances include polymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate.

[0011] Preferably, the catalyst includes triethylenediamine, pentamethyldiethylenetriamine, and dibutyltin dilaurate.

[0012] Preferably, the foam stabilizer includes silicone oil.

[0013] Preferably, the foaming agent includes dichlorofluoroethane.

[0014] Preferably, (2) the temperature of the bubble is 20-35℃; the aging temperature is 25-60℃ and the time is 12-36h.

[0015] The preferred method for preparing DOPO amino hydrochloride is as follows:

[0016] (1) Add dichloromethane, triethylamine, 3-nitrophenyl isocyanate, and 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in a molar ratio of (6.6-7.4):(2-2.4):1 to a flask, heat to 40-45℃, stir and reflux for 18-24h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain DOPO nitrobenzene.

[0017] (2) Add ethanol, DOPO nitrobenzene (molar ratio 1:(6-8), and stannous chloride to a flask, and add concentrated hydrochloric acid (28-37% by mass) dropwise. Heat to 75-85℃, stir and reflux for 3-4 hours. After filtration, wash the product successively with hydrochloric acid solution and water. Recrystallize the product in a mixed solution of 1,4-dioxane and water to obtain DOPO amino hydrochloride. The preparation reaction formula is:

[0018] .

[0019] The beneficial technical effects of this invention are as follows: DOPO amino hydrochloride is prepared by using 3-nitrophenyl isocyanate, 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc. as raw materials. It contains an amino hydrochloride structure, which forms an electrostatic interaction with the negative charge in montmorillonite, thereby achieving organic modification of the surface of montmorillonite. This is beneficial to improving the agglomeration problem of montmorillonite and enhancing its dispersibility.

[0020] This invention involves blending and foaming polyester polyol, isocyanate substances, flame-retardant modified montmorillonite, foaming agents, and catalysts to obtain a flame-retardant shoe sole material. DOPO amino hydrochloride contains the same urethane groups as polyurethane, improving the interfacial forces and compatibility between montmorillonite and polyurethane foam materials. Furthermore, the modified montmorillonite is less prone to agglomeration, exhibiting good dispersibility and significantly improving the mechanical properties of the polyurethane foam shoe sole material, demonstrating higher compressive strength. Simultaneously, DOPO amino hydrochloride contains the DOPO structure and multiple nitrogen elements, forming a nitrogen-phosphorus flame retardant that, together with montmorillonite, creates a synergistic flame-retardant system, enhancing the flame-retardant performance of the shoe sole material. Attached Figure Description

[0021] Figure 1 The 1H NMR spectrum of DOPO nitrobenzene prepared in Example 1 of this invention;

[0022] Figure 2 The 1H NMR spectrum of DOPO amino hydrochloride prepared in Example 1 of this invention. Detailed Implementation

[0023] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not imply that the scope of the invention is limited thereto.

[0024] The montmorillonite described below is sodium-based montmorillonite with an average particle size of 325 mesh, sourced from Hebei Guanchuan New Material Technology Co., Ltd.

[0025] Example 1:

[0026] (1) Add 50 mL of dichloromethane, 33 mmol of triethylamine, 12 mmol of 3-nitrophenyl isocyanate and 5 mmol of 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to a flask, heat to 40 °C, stir and reflux for 24 h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain DOPO nitrobenzene.

[0027] (2) Add 100 mL of ethanol, 5 mmol of DOPO nitrobenzene and 30 mmol of stannous chloride to the flask, add 7 mL of concentrated hydrochloric acid with a mass fraction of 28%, heat to 85 °C, stir and reflux for 3 h, filter and wash the product with 5% hydrochloric acid solution and water in sequence. The product is recrystallized in a mixed solution of 1,4-dioxane and water to obtain DOPO amino hydrochloride.

[0028] (3) Add 400 mL of water and 10 g of montmorillonite to the flask, disperse ultrasonically for 1 h, then add 100 mL of 1,4-dioxane solvent and 8 g of DOPO amino hydrochloride, heat to 70 °C, stir for 3 h, dry to remove solvent, and obtain flame retardant modified montmorillonite.

[0029] (4) Mix 200g of polyester polyol (model Jining Fangyu Chemical YHY450C, the same below), 6g of flame retardant modified montmorillonite, 12.3g of triethanolamine, 41g of monofluorodichloroethane, 7g of foaming agent silicone oil (model silicone oil 8110, the same below), 3.7g of catalyst triethylenediamine, 0.4g of dibutyltin dilaurate, and 4.5g of water. Then quickly mix it with 226g of isocyanate substance polymethylene polyphenyl polyisocyanate, add it to the mold, foam it at 25°C, and cure it at 40°C for 24 hours to obtain flame retardant shoe sole material.

[0030] Example 2:

[0031] (1) Add 40 mL of dichloromethane, 37 mmol of triethylamine, 10 mmol of 3-nitrophenyl isocyanate, and 5 mmol of 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to a flask, heat to 45 °C, stir and reflux for 18 h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain DOPO nitrobenzene.

[0032] (2) Add 130 mL of ethanol, 5 mmol of DOPO nitrobenzene and 40 mmol of stannous chloride to the flask, add 6 mL of concentrated hydrochloric acid with a mass fraction of 37%, heat to 75 °C, stir and reflux for 4 h, filter and wash the product with hydrochloric acid solution and water in sequence, recrystallize the product in a mixed solution of 1,4-dioxane and water to obtain DOPO amino hydrochloride.

[0033] (3) Add 500 mL of water and 10 g of montmorillonite to the flask, disperse ultrasonically for 1.5 h, then add 150 mL of 1,4-dioxane solvent and 11 g of DOPO amino hydrochloride, heat to 60 °C, stir for 10 h, dry to remove solvent, and obtain flame retardant modified montmorillonite.

[0034] (4) Mix 200g of polyester polyol, 10g of flame retardant modified montmorillonite, 10.4g of 1,4-butanediol, 54g of monofluorodichloroethane, 4g of foaming agent silicone oil, 2.9g of catalyst triethylenediamine, 0.3g of dibutyltin dilaurate and 3g of water. Then quickly mix with 185g of isocyanate substance polymethylene polyphenyl polyisocyanate and 63g of diphenylmethane diisocyanate. Add to the mold, foam at 20°C and mature at 25°C for 36h to obtain flame retardant shoe sole material.

[0035] Example 3:

[0036] (1) Add 50 mL of dichloromethane, 33 mmol of triethylamine, 12 mmol of 3-nitrophenyl isocyanate and 5 mmol of 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to a flask, heat to 40 °C, stir and reflux for 24 h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain DOPO nitrobenzene.

[0037] (2) Add 100 mL of ethanol, 5 mmol of DOPO nitrobenzene and 30 mmol of stannous chloride to the flask, add 7 mL of concentrated hydrochloric acid with a mass fraction of 28%, heat to 85 °C, stir and reflux for 3 h, filter and wash the product with 5% hydrochloric acid solution and water in sequence. The product is recrystallized in a mixed solution of 1,4-dioxane and water to obtain DOPO amino hydrochloride.

[0038] (3) Add 500 mL of water and 10 g of montmorillonite to the flask, sonicate for 1 h, then add 200 mL of 1,4-dioxane solvent and 14 g of DOPO amino hydrochloride, heat to 90 °C, stir for 4 h, dry to remove solvent, and obtain flame retardant modified montmorillonite.

[0039] (4) Mix 200g of polyester polyol, 15g of flame retardant modified montmorillonite, 10.7g of 1,4-butanediol, 36g of monofluorodichloroethane, 9g of foaming agent silicone oil, 5g of pentamethyldiethylenetriamine, 0.6g of dibutyltin dilaurate, and 4.8g of water. Then quickly mix with 232g of isocyanate substance polymethylene polyphenyl polyisocyanate, add to the mold, foam at 35℃, and cure at 60℃ for 12h to obtain flame retardant shoe sole material.

[0040] Example 4:

[0041] (1) Add 50 mL of dichloromethane, 33 mmol of triethylamine, 12 mmol of 3-nitrophenyl isocyanate and 5 mmol of 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to a flask, heat to 40 °C, stir and reflux for 24 h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain DOPO nitrobenzene.

[0042] (2) Add 100 mL of ethanol, 5 mmol of DOPO nitrobenzene and 30 mmol of stannous chloride to the flask, add 7 mL of concentrated hydrochloric acid with a mass fraction of 28%, heat to 85 °C, stir and reflux for 3 h, filter and wash the product with 5% hydrochloric acid solution and water in sequence. The product is recrystallized in a mixed solution of 1,4-dioxane and water to obtain DOPO amino hydrochloride.

[0043] (3) Add 600 mL of water and 10 g of montmorillonite to the flask, sonicate for 1.5 h, then add 200 mL of 1,4-dioxane solvent and 18 g of DOPO amino hydrochloride, heat to 90 °C, stir for 6 h, dry to remove solvent, and obtain flame retardant modified montmorillonite.

[0044] (4) Mix 200g of polyester polyol, 20g of flame retardant modified montmorillonite, 12.8g of triethanolamine, 47g of dichlorofluoroethane, 12g of foaming agent silicone oil, 3g of catalyst triethylenediamine, 0.5g of dibutyltin dilaurate and 3.9g of water. Then quickly mix with 233g of isocyanate substance polymethylene polyphenyl polyisocyanate, add to the mold, foam at 25℃ and mature at 40℃ for 36h to obtain flame retardant shoe sole material.

[0045] Comparative Example 1:

[0046] (1) Mix 200g polyester polyol, 6g montmorillonite, 12.3g triethanolamine, 41g dichlorofluoroethane, 7g silicone oil as a foaming agent, 3.7g triethylenediamine as a catalyst, 0.4g dibutyltin dilaurate, and 4.5g water. Then quickly mix with 226g isocyanate substance polymethylene polyphenyl polyisocyanate, add to a mold, foam at 25°C, and cure at 40°C for 24 hours to obtain shoe sole material.

[0047] Comparative Example 2:

[0048] (1) Add 400 mL of water and 10 g of montmorillonite to a flask, sonicate for 1 h, then add 100 mL of 1,4-dioxane solvent and 8 g of 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 70 °C, stir for 3 h, dry to remove solvent, and obtain flame retardant-montmorillonite blend.

[0049] (2) Mix 200g of polyester polyol, 6g of flame retardant-montmorillonite blend, 12.3g of triethanolamine, 41g of dichlorofluoroethane, 7g of foaming agent silicone oil, 3.7g of catalyst triethylenediamine, 0.4g of dibutyltin dilaurate and 4.5g of water. Then quickly mix with 226g of isocyanate substance polymethylene polyphenyl polyisocyanate, add to the mold and foam at 25°C. Then cure at 40°C for 24 hours to obtain flame retardant shoe sole material.

[0050] Comparative Example 3:

[0051] (1) Add 50 mL of dichloromethane, 33 mmol of triethylamine, 12 mmol of 3-nitrophenyl isocyanate and 5 mmol of hydroquinone to a flask, heat to 40 °C, stir and reflux for 24 h, extract with water, dry the dichloromethane organic phase with anhydrous sodium sulfate, filter and evaporate by rotary evaporation, recrystallize the product in toluene to obtain nitrobenzene derivatives.

[0052] (2) Add 100 mL of ethanol, 5 mmol of nitrobenzene derivative, and 30 mmol of stannous chloride to a flask, and add 7 mL of 28% concentrated hydrochloric acid dropwise. Heat to 85 °C, stir and reflux for 3 h. After filtration, wash the product successively with 5% hydrochloric acid solution and water. Recrystallize the product in a mixed solution of 1,4-dioxane and water to obtain an amino hydrochloride derivative. The structural formula is... .

[0053] (3) Add 400 mL of water and 10 g of montmorillonite to the flask, sonicate for 1 h, then add 100 mL of 1,4-dioxane solvent and 8 g of amino hydrochloride derivative, heat to 70 °C, stir for 3 h, dry to remove solvent, and obtain modified montmorillonite.

[0054] (4) Mix 200g of polyester polyol, 6g of modified montmorillonite, 12.3g of triethanolamine, 41g of dichlorofluoroethane, 7g of foaming agent silicone oil, 3.7g of catalyst triethylenediamine, 0.4g of dibutyltin dilaurate and 4.5g of water. Then quickly mix with 226g of isocyanate substance polymethylene polyphenyl polyisocyanate, add to the mold and foam at 25°C. Then cure at 40°C for 24 hours to obtain the shoe sole material.

[0055] The compressive strength of the sole material was tested according to the method specified in GB / T 8813-2020 standard.

[0056] The combustion performance of the flame-retardant shoe sole material was tested using a cone calorimeter, with a radiation intensity of 35 kW / m². 2 .

[0057] Table 1 Performance of shoe sole materials

[0058]

[0059] The polyurethane foam sole material in Comparative Example 1 has low compressive strength, mainly because the added montmorillonite has poor dispersibility and poor compatibility with polyurethane, resulting in low mechanical properties and compressive strength of the sole material. In addition, the sole material has a large peak heat release rate, total heat release, and total smoke release, and poor flame retardancy.

[0060] Each embodiment utilizes the amino hydrochloride structure (-NH2HCl) of DOPO amino hydrochloride to form an electrostatic interaction with the negative charge in montmorillonite, thereby achieving surface organic modification of montmorillonite. This is beneficial for improving the aggregation problem of montmorillonite and enhancing its dispersibility. Furthermore, DOPO amino hydrochloride contains the same carbamate groups as polyurethane. This further enhances the interfacial forces and compatibility between montmorillonite and polyurethane foam, significantly improving the mechanical properties of polyurethane foam shoe sole materials and exhibiting higher compressive strength. Furthermore, DOPO amino hydrochloride contains DOPO structure and multiple nitrogen elements, forming a nitrogen-phosphorus flame retardant that, together with montmorillonite, forms a synergistic flame retardant system, reducing the peak heat release rate, total heat release, and total smoke release during the combustion of the shoe sole material, thus exhibiting excellent flame retardant properties.

[0061] The 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide of Comparative Example 2 does not contain amino hydrochloride structure and urethane group, making it difficult to form an interaction with the surface of montmorillonite. It has a poor modification effect on montmorillonite, cannot improve the agglomeration problem of montmorillonite, and does not improve the interfacial force and compatibility between montmorillonite and polyurethane foam material, resulting in low compressive strength of the shoe sole material.

[0062] The amino hydrochloride derivatives in Comparative Example 3 do not contain the DOPO flame-retardant structure, making it difficult to improve the flame-retardant performance of the sole material. This results in a relatively large peak heat release rate, total heat release, and total smoke release of the sole material, but lower than those in Comparative Example 1. This is mainly because the amino hydrochloride derivatives improve the agglomeration problem of montmorillonite and have good dispersion in polyurethane foam sole materials, which is beneficial to improving flame-retardant performance.

[0063] The above description is merely a preferred embodiment of the present invention and does not limit the scope of patent protection of the present invention. Any equivalent modifications made based on the content of the present invention specification, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A flame-retardant shoe sole material, characterized in that, The flame-retardant sole material comprises 100 parts by weight of polyester polyol, 3-10 parts by weight of flame-retardant modified montmorillonite, 5.2-6.4 parts by weight of chain extender, 18-27 parts by weight of foaming agent, 2-6 parts by weight of foam leveling agent, 1.6-2.8 parts by weight of catalyst, 1.5-2.4 parts by weight of water, and 113-124 parts by weight of isocyanate substance; The preparation method of flame retardant modified montmorillonite is as follows: Add water and 100 parts by weight of montmorillonite to a flask, ultrasonically disperse for 1-1.5 hours, then add 1,4-dioxane solvent and 80-180 parts by weight of the following: [Structure formula omitted] DOPO amino hydrochloride is heated to 60-90℃, stirred for 3-10 hours, dried to remove solvent, and flame retardant modified montmorillonite is obtained.

2. The flame-retardant shoe sole material according to claim 1, characterized in that, The chain extender is any one or a combination of 1,4-butanediol and triethanolamine; the isocyanate is any one or a combination of polymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate.

3. The flame-retardant shoe sole material according to claim 1, characterized in that, The catalyst is any one or a combination of triethylenediamine, pentamethyldiethylenetriamine, and dibutyltin dilaurate.

4. The flame-retardant shoe sole material according to claim 1, characterized in that, The foaming agent is silicone oil; the foaming agent is dichlorofluoroethane.

5. The flame-retardant shoe sole material according to claim 1, characterized in that, The preparation method of the DOPO amino hydrochloride is as follows: (1) Add dichloromethane, triethylamine, 3-nitrophenyl isocyanate, and 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to a flask, heat to 40-45°C, stir and reflux for 18-24 h, extract and recrystallize the product to obtain DOPO nitrobenzene; (2) Add ethanol, DOPO nitrobenzene and stannous chloride to the flask, add concentrated hydrochloric acid dropwise, heat to 75-85℃, stir and reflux for 3-4 hours, filter, wash the product, recrystallize to obtain DOPO amino hydrochloride.

6. The flame-retardant shoe sole material according to claim 5, characterized in that, The molar ratio of triethylamine, 3-nitrophenyl isocyanate, and 10-(2',5'-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in (1) is (6.6-7.4):(2-2.4):

1.

7. The flame-retardant shoe sole material according to claim 5, characterized in that, In (2), the molar ratio of DOPO nitrobenzene to stannous chloride is 1:(6-8).

8. The flame-retardant shoe sole material according to claim 5, characterized in that, The mass fraction of concentrated hydrochloric acid in (2) is 28-37%.

9. A method for preparing a flame-retardant shoe sole material as described in any one of claims 1-8, characterized in that, The preparation method is as follows: polyester polyol, flame retardant modified montmorillonite, chain extender, foaming agent, foam leveling agent, catalyst, and water are stirred and mixed evenly, and then mixed with isocyanate material, added to mold for foaming and curing to obtain flame retardant shoe sole material.

10. The method for preparing the flame-retardant shoe sole material according to claim 9, characterized in that, The foaming temperature is 20-35℃; the curing temperature is 25-60℃, and the time is 12-36h.

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