A preparation process and application of polyphosphate polyol

Abstract

The invention discloses a preparation process and application of a polyphosphate polyol. The invention conducts Schiff base polymerization reaction of adipic acid amide dibenzaldehyde monomer and 4,4-diaminodiDOPO, and performs end-capping reaction of amino alcohol compounds such as ethanolamine to obtain a novel polyphosphate polyol. Further, polymerization reaction is carried out with a diisocyanate compound to obtain a phosphorus-containing polyurethane having excellent flame retardant properties. Further, nylon 6 is used to fill and modify the phosphorus-containing polyurethane to obtain a polyurethane / nylon composite material. The phosphorus-containing polyurethane has good compatibility and interface bonding force with nylon 6, and significantly improves the tensile strength, bending strength and other mechanical properties of the polyurethane.

Description

Technical Field

[0001] The invention relates to the technical field of polyester polyols, in particular to a preparation process and application of polyphosphate polyols. Background Art

[0002] Polyurethane is a polymer obtained by polymerization of polyols and polyisocyanate compounds. The type of polyol has a lot of influence on the performance of polyurethane, mainly polyester polyols, polyether polyols, bio-based polyols, phosphorus-containing polyols, etc. Traditional polyurethane materials are not flame retardant and easy to burn, which hinders the application of polyurethane in fire retardant and other fields. Synthetic polyols containing flame retardant elements such as phosphorus and nitrogen can be used as reactive flame retardants to give polyurethane excellent flame retardant properties.

[0003] Nylon 6 is a polyamide material with excellent performance, high mechanical strength, good toughness, excellent wear resistance, and can form a gold or composite material with better mechanical properties with materials such as polyurethane, polycarbonate, ABS, etc. The amide group of nylon 6 contains urethane and the like to form hydrogen bonds, and the two have good compatibility, but when the addition amount of nylon 6 is too large, the compatibility of the two is greatly affected, and the mechanical properties of the composite material are not good. In order to improve the compatibility between nylon 6 and materials such as polyurethane, it is usually necessary to add auxiliary agents such as compatibilizers. Patent CN104744929B discloses a nylon 6 / thermoplastic polyurethane composite material and a preparation method thereof, with nylon 6 and thermoplastic polyurethane as raw materials, and the obtained composite material has excellent mechanical properties and good processability. However, the composite material needs to add auxiliary agents such as compatibilizer maleic anhydride grafted ethylene-vinyl acetate copolymer (EVA-g-MAH) to improve the compatibility between nylon 6 and polyurethane. Summary of the invention

[0004] The invention provides a polyphosphate polyol, which solves the problems of poor flame retardancy of polyurethane and poor compatibility between polyurethane and nylon materials.

[0005] The technical scheme of the present invention is: a preparation process of polyphosphate polyol: add dimethyl sulfoxide, 4,4-diaminodiDOPO, and adipic acid amide dibenzaldehyde monomer into a reaction bottle, introduce nitrogen, heat to 110-140°C, stir and react for 8-12 hours, then add an amino alcohol compound, carry out a capping reaction for 1-1.5 hours, cool, add ethanol to dilute, filter, wash the filter cake with ethanol, and dry to obtain polyphosphate polyol.

[0006] The molar amount of the dibenzaldehyde adipamide monomer is 110-125% of the molar amount of 4,4-diaminodiDOPO.

[0007] Wherein, the structural formula of the adipic acid amide dibenzaldehyde monomer is formula (I):

[0008]

[0009] Among them, the structural formula of the amino alcohol compound is n is any integer value from 2 to 6.

[0010] The preparation process of the adipic acid amide benzaldehyde monomer is as follows: at 0-5°C, dichloromethane, 4-formaldehyde benzoyl chloride, 1,6-hexanediamine and triethylamine are added to a reaction bottle, wherein the molar amounts of 4-formaldehyde benzoyl chloride and triethylamine are 200-210% and 200-210% of the molar amount of 1,6-hexanediamine, respectively; then, the mixture is heated to 15-25°C, reacted for 12-18h, rotary evaporated, and separated by column chromatography to obtain the adipic acid amide benzaldehyde monomer.

[0011] A method for preparing phosphorus-containing polyurethane by using polyphosphate polyol: adding polyphosphate polyol and diisocyanate compound into a reaction bottle, introducing nitrogen, heating to 70-80°C, reacting for 3-4h, then reducing the temperature to 45-50°C, adding acetone, 1,4-butanediol and dibutyltin dilaurate, reacting for 40-60min, pouring the solution into a mold, vacuum degassing, then curing at 60-70°C for 18-36h, and finally heat treating at 100-120°C for 5-8h to obtain phosphorus-containing polyurethane.

[0012] The molar amount of the diisocyanate compound is 230-260% of the molar amount of the polyphosphate polyol.

[0013] The diisocyanate compounds include isophorone diisocyanate, toluene-2,4-diisocyanate, and 4,4'-methylenebis(phenyl isocyanate).

[0014] Among them, the application of phosphorus-containing polyurethane in polyurethane / nylon composite materials: the phosphorus-containing polyurethane and nylon 6 are mixed in a mixer, and then in a twin-screw extruder, the screw speed is controlled to be 30-50r / min, the temperature of sections 1-6 is 180-235°C, extrusion, granulation, and finally injection molding by an injection molding machine, the injection molding temperature is 220-230°C, to obtain a polyurethane / nylon composite material.

[0015] The mass of nylon 6 contains 10-60% of the mass of the phosphorus-containing polyurethane.

[0016] The technical effect produced by the present invention is as follows: the present invention conducts a Schiff base polymerization reaction of adipic acid amide dibenzaldehyde monomer and 4,4-diaminodiDOPO, and performs an end-capping reaction of amino alcohol compounds such as ethanolamine to obtain a novel polyphosphate ester polyol. Further polymerization reaction is carried out with a diisocyanate compound to obtain a phosphorus-containing polyurethane, thereby introducing a flame retardant structure containing double DOPO into the polyurethane molecular chain, which can play a role in gas phase and condensed phase flame retardancy. During combustion, the DOPO flame retardant structure can be thermally decomposed to produce free radicals such as phosphorus and oxygen, which can quench the active free radicals of the combustion chain reaction and terminate the chain combustion reaction. Increasing the thermal decomposition of DOPO to generate acidic substances such as metaphosphoric acid and phosphoric acid can promote the dehydration and carbonization of polyurethane groups, forming a continuous and dense carbon-based protective layer, which can isolate oxygen and hinder heat transfer. The peak heat release rate of polyurethane with a content of only 41.0-52.6kW / m 2 The total heat release is only 5.13-5.98MJ / m 2 , the limiting oxygen index reaches 30.5-31.4%, showing excellent flame retardant properties.

[0017] The present invention utilizes nylon 6 to fill and modify phosphorus-containing polyurethane to obtain a polyurethane / nylon composite material. Nylon 6 itself has high mechanical strength and toughness, and the molecular chain of the phosphorus-containing polyurethane contains a caproamide structure, which has structural similarity with the caprolactam structure in nylon 6, and can improve the compatibility of the phosphorus-containing polyurethane and nylon 6. At the same time, the amide bond of the caproamide structure can interact with the amide bond in nylon 6 by hydrogen bonding, etc., and significantly improve the interface bonding force between the two. Nylon 6 is added to the polyurethane, and the mechanical properties of the polyurethane are significantly improved, and the tensile strength reaches 59.4-68.2MPa. The bending strength reaches 73.7-86.1MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the reaction formula for preparing adipic acid amide dibenzaldehyde monomer.

[0019] Figure 2 This is the reaction formula for preparing polyphosphate polyol. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] 4-Formylbenzoyl chloride was prepared according to the method with DOI number 10.1039 / b917209b and document name "Development of 2,6-carboxy-substituted boron dipyrromethene (BODIPY) as a novel scaffold of ratiometric fluorescent probes for live cell imaging".

[0022] At 0°C, add 10 mL of toluene, 8 mL of thionyl chloride, and 3.3 mmol of 4-formylbenzoic acid to a reaction bottle equipped with a condenser reflux tube, heat to 70°C for 1 h, rotary evaporate, and dry to obtain 4-formylbenzoyl chloride.

[0023] 4,4-DiaminodiDOPO was prepared according to the method with DOI number 10.1007 / s10973-020-09688-7 and literature name "Aphosphorus-and nitrogen-containing DOPO derivative as fame retardant for polylactic acid (PLA)".

[0024] Add 0.03 mol 4,4-diaminobenzophenone and 0.18 mol 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to the reaction bottle, heat to 180°C, react for 3 hours, cool to 100°C, add 150 mL toluene, precipitate, filter, wash the filter cake with toluene, and recrystallize with tetrahydrofuran to obtain 4,4-diaminodiDOPO.

[0025] Example 1

[0026] At 5°C, 30 mL of dichloromethane, 20 mmol of 4-formylbenzoyl chloride, 10 mmol of 1,6-hexanediamine, and 20 mmol of triethylamine were added to the reaction bottle, and then heated to 15°C, reacted for 18 hours, and rotary evaporated. A solution of V (petroleum ether): V (ethyl acetate) = 9:1 was used as the eluent, and silica gel column chromatography was performed to obtain adipic acid amide dibenzaldehyde monomer. The yield was 5.45 g, light yellow powder.

[0027] Example 2

[0028] At 0°C, 40 mL of dichloromethane, 21 mmol of 4-formylbenzoyl chloride, 10 mmol of 1,6-hexanediamine, and 21 mmol of triethylamine were added to the reaction bottle, and then heated to 25°C, reacted for 12 hours, and rotary evaporated. A solution of V (petroleum ether): V (ethyl acetate) = 9:1 was used as the eluent, and silica gel column chromatography was performed to obtain adipic acid amide dibenzaldehyde monomer. The yield was 5.17 g, light yellow powder.

[0029] Example 3

[0030] Add 300 mL of dimethyl sulfoxide, 60 mmol of 4,4-diaminodiDOPO, and 72 mmol of adipic acid amide dibenzaldehyde monomer (prepared in Example 1) into the reaction bottle, introduce nitrogen, heat to 110° C., stir and react for 12 h, and then add 22 mmol of ethanolamine. The end-capping reaction was carried out for 1 hour, cooled, diluted with ethanol, filtered, the filter cake was washed with ethanol, and dried to obtain a polyphosphate polyol.

[0031] Add 50mmol polyphosphate polyol and 130mmol toluene-2,4-diisocyanate into the reaction bottle, introduce nitrogen, heat to 75℃, react for 3h, then reduce the temperature to 45℃, add 80mL acetone, 60mmol 1,4-butanediol and 0.14mmol dibutyltin dilaurate, react for 40min, pour the solution into a mold, vacuum degas, and then cure at 60℃ for 24h, and finally heat treat at 120℃ for 5h to obtain phosphorus-containing polyurethane.

[0032] Example 4

[0033] Add 300 mL of dimethyl sulfoxide, 60 mmol of 4,4-diaminodiDOPO, and 66 mmol of adipic acid amide dibenzaldehyde monomer (prepared in Example 1) into the reaction bottle, introduce nitrogen, heat to 140°C, stir and react for 8 h, then add 22 mmol of 4-amino-1-butanol The end-capping reaction was carried out for 1.5 hours, cooled, diluted with ethanol, filtered, the filter cake was washed with ethanol, and dried to obtain a polyphosphate polyol.

[0034] Add 50mmol polyphosphate polyol and 124mmol isophorone diisocyanate into the reaction bottle, introduce nitrogen, heat to 80℃, react for 3h, then reduce the temperature to 50℃, add 80mL acetone, 60mmol 1,4-butanediol, and 0.14mmol dibutyltin dilaurate, react for 60min, pour the solution into a mold, vacuum degas, and then cure at 70℃ for 18h, and finally heat treat at 100℃ for 8h to obtain phosphorus-containing polyurethane.

[0035] Example 5

[0036] 400 mL of dimethyl sulfoxide, 60 mmol of 4,4-diaminodiDOPO, and 75 mmol of adipic acid amide dibenzaldehyde monomer (prepared in Example 1) were added to the reaction bottle, nitrogen was introduced, and the mixture was heated to 120° C. and stirred for 12 h. Then, 22 mmol of 6-amino-1-hexanol was added. The end-capping reaction was carried out for 1 hour, cooled, diluted with ethanol, filtered, the filter cake was washed with ethanol, and dried to obtain a polyphosphate polyol.

[0037] Add 50mmol polyphosphate polyol and 115mmol 4,4'-methylenebis(phenyl isocyanate) into the reaction bottle, introduce nitrogen, heat to 70°C, react for 4h, then reduce the temperature to 50°C, add 80mL acetone, 55mmol 1,4-butanediol, and 0.13mmol dibutyltin dilaurate, react for 40min, pour the solution into a mold, vacuum degas, and then cure at 60°C for 36h, and finally heat treat at 110 for 6h to obtain a phosphorus-containing polyurethane.

[0038] The difference between Comparative Example 1 and Example 3 is that conventional polybutylene adipate polyol is used instead of polyphosphate polyol.

[0039] Add 50 mmol polybutylene adipate and 130 mmol toluene-2,4-diisocyanate to the reaction bottle, introduce nitrogen, heat to 75°C, react for 3 hours, then reduce the temperature to 45°C, add 80 mL acetone, 60 mmol 1,4-butanediol, and 0.14 mmol dibutyltin dilaurate, react for 40 minutes, pour the solution into a mold, vacuum degas, and then cure at 60°C for 24 hours, and finally heat treat at 120 for 5 hours to obtain polyurethane.

[0040] The combustion performance of polyurethane was tested using a cone calorimeter with a radiation intensity of 35kW / m 2 The limiting oxygen index is tested according to GB / T2406.1-2008 method.

[0041] Table 1 Polyurethane flame retardant performance test

[0042]

[0043] As shown in Table 1, the peak heat release rate of the polyurethane prepared in Comparative Example 1 using conventional polybutylene adipate polyol as raw material reached 182.1 kW / m 2 The total heat release reaches 16.97MJ / m 2 , the limiting oxygen index is only 21.3%, and the flame retardancy is very poor.

[0044] In Examples 3-5, polyphosphate polyol was used as the raw material, and the peak heat release rate of the obtained polyurethane was only 41.0-52.6 kW / m 2 The total heat release is only 5.13-5.98MJ / m 2 , the limiting oxygen index reaches 30.5-31.4%, showing excellent flame retardant properties. This is because the molecular chain of polyphosphate polyol contains a double DOPO flame retardant structure, which can play a role in gas phase and condensed phase flame retardancy. During combustion, the DOPO flame retardant structure can thermally decompose to produce free radicals such as phosphorus and oxygen, which can quench the active free radicals of the combustion chain reaction and terminate the chain combustion reaction. Increasing the thermal decomposition of DOPO to produce acidic substances such as metaphosphoric acid and phosphoric acid can promote the dehydration and carbonization of polyurethane groups, forming a continuous and dense carbon-based protective layer, which can isolate oxygen and hinder heat transfer.

[0045] Example 6

[0046] 1 kg of phosphorus-containing polyurethane (prepared by Example 4) and 100 g of nylon 6 were mixed in a mixer, and then extruded and granulated in a twin-screw extruder with the screw speed controlled at 30 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. The mixture was then injection molded with an injection molding machine at a temperature of 220°C to obtain a polyurethane / nylon composite material.

[0047] Example 7

[0048] 1 kg of phosphorus-containing polyurethane (prepared by Example 4) and 250 g of nylon 6 were mixed in a mixer, and then extruded and granulated in a twin-screw extruder with the screw speed controlled at 40 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. The mixture was then injection molded with an injection molding machine at a temperature of 230°C to obtain a polyurethane / nylon composite material.

[0049] Example 8

[0050] 1 kg of phosphorus-containing polyurethane (prepared by Example 4) and 400 g of nylon 6 were mixed in a mixer, and then extruded and granulated in a twin-screw extruder with the screw speed controlled at 50 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. The mixture was then injection molded with an injection molding machine at a temperature of 220°C to obtain a polyurethane / nylon composite material.

[0051] Example 9

[0052] 1 kg of phosphorus-containing polyurethane (prepared by Example 4) and 600 g of nylon 6 were mixed in a mixer, and then extruded and granulated in a twin-screw extruder with the screw speed controlled at 50 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. The polyurethane material was obtained.

[0053] Comparative Example 2

[0054] 1 kg of phosphorus-containing polyurethane (prepared by Example 4) was placed in a twin-screw extruder with the screw speed controlled at 30 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. It was extruded and granulated and finally injection molded by an injection molding machine at a temperature of 220°C to obtain a polyurethane / nylon composite material.

[0055] Comparative Example 3

[0056] 1 kg of polyurethane (prepared by Comparative Example 1) was placed in a twin-screw extruder with the screw speed controlled at 30 r / min and the temperatures of sections 1-6 at 180°C, 200°C, 225°C, 225°C, 235°C, and 230°C. It was extruded and granulated and finally injection molded by an injection molding machine at a temperature of 220°C to obtain a polyurethane / nylon composite material.

[0057] The tensile properties are tested according to GB / T 1040.1-2018; the bending properties are tested according to GB / T 9341-2008.

[0058] Table 2 Mechanical properties test of composite materials

[0059]

[0060] Compared with Example 6, the phosphorus-containing polyurethane of Comparative Example 2, in which nylon 6 is not added, has the lowest tensile strength, elongation at break and flexural strength, and the worst mechanical properties.

[0061] The phosphorus-containing polyurethane of Examples 6-9 is added with nylon 6, which has high mechanical strength and toughness. The molecular chain of the phosphorus-containing polyurethane contains a caproamide structure. Similar to the caprolactam structure in nylon 6 The structural similarity can improve the compatibility of phosphorus-containing polyurethane and nylon 6. At the same time, the amide bond of the caproamide structure can interact with the amide bond in nylon 6 through hydrogen bonding, which significantly improves the interfacial bonding between the two. The addition of nylon 6 to polyurethane significantly improves the mechanical properties of polyurethane, with a tensile strength of 59.4-68.2MPa and a flexural strength of 73.7-86.1MPa.

[0062] Nylon 6 is also added to the polyurethane of Comparative Example 3, but its tensile strength and flexural strength are lower than those of Example 6. This may be because the polyurethane does not contain a caproic acid amide structure and has poor compatibility with nylon 6, resulting in poor reinforcement effect of nylon 6.

[0063] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a polyphosphate polyol, characterized in that: The preparation process comprises: adding dimethyl sulfoxide, 4,4-diaminodiDOPO, and adipic acid amide dibenzaldehyde monomers into a reaction bottle, introducing nitrogen, heating to a reaction temperature, stirring for reaction, then adding an amino alcohol compound, performing an end-capping reaction, cooling, adding ethanol for dilution, filtering, washing the filter cake, and drying to obtain a polyphosphate polyol; The molar amount of the adipic acid amide dibenzaldehyde monomer is 110-125% of the molar amount of 4,4-diaminodiDOPO; The structural formula of the adipic acid amide dibenzaldehyde monomer is formula (I):

2. The process for preparing polyphosphate polyol according to claim 1, characterized in that: The reaction temperature is 110-140° C.; the stirring reaction time is 8-12 hours; and the end-capping reaction time is 1-1.5 hours.

3. The preparation process of polyphosphate polyol according to claim 1, characterized in that: The structural formula of the amino alcohol compound is n is any integer value from 2 to 6.

4. The process for preparing polyphosphate polyol according to claim 1, characterized in that: The preparation process of the adipic acid amide benzaldehyde monomer is as follows: at 0-5° C., dichloromethane, 4-formylbenzoyl chloride, 1,6-hexanediamine and triethylamine are added into a reaction bottle, wherein the molar amounts of 4-formylbenzoyl chloride and triethylamine are 200-210% and 200-210% of the molar amount of 1,6-hexanediamine respectively; then, the mixture is heated to 15-25° C., reacted for 12-18 hours, rotary evaporated, and separated by column chromatography to obtain the adipic acid amide benzaldehyde monomer.

5. A method for preparing phosphorus-containing polyurethane using the polyphosphate polyol obtained by the preparation process according to any one of claims 1 to 4, characterized in that: Add polyphosphate polyol and diisocyanate compound into the reaction bottle, introduce nitrogen, heat to 70-80°C, react for 3-4h, then reduce the temperature to 45-50°C, add acetone, 1,4-butanediol and dibutyltin dilaurate, react for 40-60min, pour the solution into a mold, vacuum degas, then cure at 60-70°C for 18-36h, and finally heat treat at 100-120 for 5-8h to obtain phosphorus-containing polyurethane.

6. The method for preparing phosphorus-containing polyurethane using the polyphosphate polyol obtained by the preparation process according to claim 5, characterized in that: The molar amount of the diisocyanate compound is 230-260% of the molar amount of the polyphosphate polyol.

7. The method for preparing phosphorus-containing polyurethane using the polyphosphate polyol obtained by the preparation process according to claim 6, characterized in that: The diisocyanate compound includes isophorone diisocyanate, toluene-2,4-diisocyanate, and 4,4'-methylenebis(phenyl isocyanate).

8. Use of the phosphorus-containing polyurethane prepared by the method according to claim 7 in a polyurethane / nylon composite material, characterized in that: The phosphorus-containing polyurethane and nylon 6 are mixed in a mixer, then extruded in a twin-screw extruder, granulated, and finally injection-molded by an injection molding machine to obtain a polyurethane / nylon composite material.

9. The use of the phosphorus-containing polyurethane in a polyurethane / nylon composite material according to claim 8, characterized in that: The mass of the nylon 6 contains 10-60% of the mass of the phosphorus-containing polyurethane.

10. The use of the phosphorus-containing polyurethane in a polyurethane / nylon composite material according to claim 8, characterized in that: The screw speed of the twin-screw extruder during extrusion is 30-50r / min, and the temperature of sections 1-6 is 180-235°C; the injection molding temperature of the injection molding machine is 220-230°C.

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