PREPARATION METHOD AND APPLICATION OF REACTIVE POLYURETHANE FLAME RETARDANT

Abstract

The polyurethane flame retardant is prepared by compounding poly(diphosphophosphazene) (PDPP) and derivatives thereof, poly(diphosphate phosphazene) (MPDPP) (where M=Mg.sup.2+, Ca.sup.2+, transition metal ions, rare earth ions and the like) and poly(diphosphonic phosphazene). Since a phosphate group in the PDPP and an unreacted phosphate group in the MPDPP in the compound and an unreacted hydroxyl in the phosphate group may react with isocyanate, the flame retardant is a reactive flame retardant. Due to the reaction between the flame retardant and the isocyanate, the flame retardant is uniformly distributed in polyurethane and has a better flame-retardant effect. The flame retardant contains multiple flame-retardant components, namely polyphosphazene group, phosphate ester and phosphate salt. Due to the synergistic effect, the flame retardant has good flame-retardant properties, and can be used for various polyurethane materials.

Claims

1. A reactive polyurethane flame retardant, wherein the flame retardant is obtained by compounding poly(diphosphate phosphazene), poly(diphosphonicphosphazene) and metal poly(diphosphonicphosphazene) salt; and a mass ratio of the poly(diphosphate phosphazene) to the poly(diphosphonicphosphazene) to the metal poly(diphosphonicphosphazene) salt is 6:1:1-1:3:4.

2. A preparation method of the reactive polyurethane flame retardant according to claim 1, comprising the following steps: grinding a metal poly(diphosphonicphosphazene) salt for 1-2 h; adding the poly(diphosphonicphosphazene) to continue grinding for 0.5-2 h; adding the poly(diphosphate phosphazene) and a solvent to obtain a mixture, and grinding the mixture for 0.5-2 h.

3. The preparation method according to claim 2, wherein the poly(diphosphate phosphazene)is prepared by a method comprising the following steps: carrying out a ring-opening polymerization with hexachlorocyclotriphosphazene as a raw material in a high-boiling-point solvent at 210-250° C. to obtain poly(dichlorophosphazene); [[W]]wherein the high-boiling-point solvent has a boiling point of higher than 220° C. and is stable to the hexachlorocyclotriphosphazene and the poly(dichlorophosphazene); and reacting the poly(dichlorophosphazene) with triphosphite at 100-120° C. to obtain the poly(diphosphate phosphazene).

4. The preparation method according to claim 3, wherein the poly(diphosphonicphosphazene) is prepared by a method comprising the following step: hydrolyzing the poly(diphosphate phosphazene) in concentrated hydrochloric acid to obtain the poly(diphosphonicphosphazene).

5. The preparation method according to claim 4, wherein the metal poly(diphosphonicphosphazene) salt is prepared by a method comprising the following step: reacting the poly(diphosphonicphosphazene) with a metal ion solution to obtain the metal poly(diphosphonicphosphazene) salt.

6. A preparation method of a reactive polyurethane flame retardant, wherein the reactive polyurethane flame retardant is a compound obtained by compounding poly(diphosphate phosphazene), poly(bis(dialkoxyphosphate)phosphazene) and poly(diphosphophosphazene); wherein in the reactive polyurethane flame retardant, since a phosphate group in the poly(diphosphophosphazene) and an unreacted phosphate group in the poly(diphosphate phosphazene) in the compound and an unreacted hydroxyl in the phosphate group react with isocyanate, the reactive polyurethane flame retardant has a reactive flame retardant effect; due to the reaction between the reactive polyurethane flame retardant and the isocyanate, the reactive polyurethane flame retardant is uniformly distributed in a polyurethane material to produce a better flame-retardant effect; the preparation method of the reactive polyurethane flame retardant comprises the following steps: (1) carrying out a heated ring-opening polymerization with hexachlorocyclotriphosphazene as a raw material in a high-boiling-point solvent at 210-250° C. to obtain poly(dichlorophosphazene); reacting the poly(dichlorophosphazene) with triphosphate at 100-120° C. to obtain the poly(bis(dialkoxyphosphate)phosphazene); hydrolyzing the poly(bis(dialkoxyphosphate)phosphazene) in concentrated hydrochloric acid to obtain the poly(diphosphophosphazene); polymerizing the poly(diphosphophosphazene) with one or more of metal ions to obtain the poly(diphosphate phosphazene); and (2) compounding the poly(diphosphate phosphazene), the poly(bis(dialkoxyphosphate)phosphazene) and the poly(diphosphophosphazene) in a certain ratio to obtain the reactive polyurethane flame retardant used for polyurethane.

7. The preparation method according to claim 3, wherein the high-boiling-point solvent is one solvent or a mixture of several solvents selected from the group consisting of aromatic solvent naphtha, diphenyl ether, sulfolane, glyceryl triacetate, pentaerythritoltetraacetate, polyethylene glycol diacetate, liquid paraffin and methylnaphthalene oil.

8. The preparation method according to claim 3, wherein the triphosphite is one phosphite or a mixture of several of phosphites selected from the group consisiting of trimethylphosphite, triethylphosphite, tripropylphosphite and triisopropylphosphite.

9. The preparation method according to claim 4, wherein a temperature of the step of hydrolyzing the poly(diphosphate phosphazene) is 110-150° C.

10. The preparation method according to claim 5, wherein a metal ion in the metal ion solution is one or more selected from the group consisting of Mg.sup.2+, Ca.sup.2+, transition metal ion or rare earth ion; and a salt of the metal ion in the metal ion solution is soluble in water and is ionizable in an aqueous solution to release the metal ion, and the salt of the metal ion is one or more selected from the group consisting of acetate, hydrochloride and nitrate.

11. The preparation method according to claim 5, wherein a mass ratio of the metal ion in the metal ion solution to the poly(diphosphophosphazene) is 2:5-3:2.

12. The preparation method according to claim 6, wherein the poly(bis(dialkoxyphosphate)phosphazene), the poly(diphosphophosphazene) and the poly(diphosphate phosphazene) are compounded in a mass ratio of 6:1:1-1:3:4; and the compounding process comprises: firstly grinding the poly(diphosphate phosphazene) for 1-2 h, then adding the poly(diphosphophosphazene) according to the mass ratio and continuing grinding for 0.5-2 h, and adding the poly(bis(dialkoxyphosphate)phosphazene) and a solvent to obtain a mixture and grinding the mixture for 0.5-2 h.

13. A flame-retardant polyurethane, wherein raw materials of the flame-retardant polyurethane are composed of a first component and a second component, wherein the first component contains: polyether polyol, polymer polyol, a catalyst, a foaming agent, a foam stabilizer, a crosslinking agent, a pore former and a reactive polyurethane flame retardant; wherein the reactive polyurethane flame retardant is the reactive polyurethane flame retardant according to claim 1; a number of parts by mass of the reactive polyurethane flame retardant is 0.1-20; the second component contains polyisocyanate; wherein the polyisocyanate comprises: one or a mixture of several selected from the group consisting of toluene diisocyanate, diphenylmethanediisocyanate, polymeric diphenylmethanediisocyanate and modified diphenylmethanediisocyanatc and mixtures thereof; and a mass ratio of the first component to the second component is 100:30-100:80.

14. The flame-retardant polyurethane according to claim 13, wherein the first component contains the following components in parts by mass: 50-100 parts of the polyether polyol; 0-50 parts of the polymer polyol; 0.2-5 parts of the catalyst; 1-8 parts of the foaming agent; 0.2-3 parts of the foam stabilizer; 0.2-6 parts of the crosslinking agent; 0-10 parts of the pore former; and 0.1-20 parts of the reactive polyurethane flame retardant.

15. The flame-retardant polyurethane according to claim 13, wherein the polyether polyol has a functionality of 3 and a relative molecular mass of 4000-9000 Da, and a primary hydroxyl content in a terminal hydroxyl is greater than 65%; the polymer polyol is a graft copolymer of polyether polyol and styrene acrylonitrile; the catalyst is a tertiary amine or a secondary amine; the foaming agent is one or a mixture of several selected from the group consisting of deionized water, polybasic primary amine and quaternary ammonium carbonate; the foam stabilizer is a polysiloxane-polyether copolymer; the crosslinking agent is an alcohol amine compound; and the pore former is a polyether polyol with an EO content of ≥50%.

16. The preparation method according to claim 6, wherein the high-boiling-point solvent is one solvent or a mixture of several solvents selected from the group consisting of aromatic solvent naphtha, diphenyl ether, sulfolane, glyceryl triacetate, pentaerythritoltetraacetate, polyethylene glycol diacetate, liquid paraffin and methylnaphthalene oil.

17. The preparation method according to claim 6, wherein the triphosphite is one phosphite or a mixture of several of phosphites selected from the group consisiting of trimethylphosphite, triethylphosphite, tripropylphosphite and triisopropylphosphite.

18. The preparation method according to claim 6, wherein a temperature of the step of hydrolyzing the poly(diphosphate phosphazene) is 110-150° C.

19. The preparation method according to claim 6, wherein a metal ion in the metal ion solution is one or more selected from the group consisting of Mg.sup.2+, Ca.sup.2+, transition metal ion or rare earth ion; and a salt of the metal ion in the metal ion solution is soluble in water and is ionizable in an aqueous solution to release the metal ion, and the salt of the metal ion is one or more selected from the group consisting of acetate, hydrochloride and nitrate.

20. The preparation method according to claim 6, wherein a mass ratio of the metal ion in the metal ion solution to the poly(diphosphophosphazene) is 2:5-3:2.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

EXAMPLE 1

Preparation of poly(dichlorophosphazene)(PDCP)

[0035] Under the protection of nitrogen, hexachlorocyclotriphosphazene (HCCP) (14.4 mmol, 5 g),sulfamic acid (0.52 mmol, 0.05 g)and a solvent diphenyl ether (15-30 mL) were respectively added into a three-necked flask equipped with a stirrer and a condenser. After introducing nitrogen for 20-40 min, the mixture was stirred and heated to 210-250° C. to carry out ring-opening polymerization reaction. When the solution became viscous, heating was stopped, the mixture was cooled and poured into a beaker containing 40-60 mL of petroleum ether to remove the unreacted raw material HCCP, the mixture was washed with petroleum ether three times, suction filtration was carried out, and the obtained solid product was dried in a vacuum drying oven at 70-90° C. for 4-8 h to obtain poly(dichlorophosphazene) (PDCP). The obtained PDCP had a yield of 70% and a viscosity average molecular weight of 60000-80000.

[0036] By using the above method, the ring-opening polymerization product may also be obtained by replacing the diphenyl ether with other solvents (one or a mixture of several of aromatic solvent naphtha, sulfolane, glyceryl triacetate, pentaerythritoltetraacetate, polyethylene glycol diacetate, liquid paraffin and methylnaphthalene oil) and by controlling the temperature at 210-250° C. or at a higher reaction temperature, except that the solvent using a low-boiling-point solvent with better solubility for the solvent is used for washing during removal of the solvent.

[0037] The yield of the ring-opening polymerization reaction using different solvents was in the range of 40%-80%, and the viscosity average molecular weight was in the range of 40000-100000.

EXAMPLE 2

Preparation of poly(diphosphate phosphazene) (PBPP)

[0038] 20 g of the obtained poly(dichlorophosphazene) was reacted with excess (50-60 mL) triethylphosphite at 100-120° C. for 5-7 h, the reaction mixture was cooled and washed with an appropriate amount of petroleum ether 3-4 times to remove excess unreacted triethylphosphite, suction filtration was carried out, and the solid was dried in a vacuum drying oven at 60-100° C. to obtain poly(diphosphate phosphazene) (PBPP). The yield of the obtained PBPP was 83%.

[0039] Using the same reaction steps, yields of reaction with different triphosphates or under different conditions are shown in Table 1.

EXAMPLE 3

Preparation of poly(diphosphonicphosphazene) (PDPP)

[0040] 25 g of the PBPP was added to 60-90 mL of concentrated hydrochloric acid and was hydrolyzed under stirring at 110-150° C. until the solution became clear. The solution was concentrated to near dryness at 110-140° C. to remove the reaction products and excess concentrated hydrochloric acid. The mixture was extracted with 30-50 mL of ethyl acetate 3-4 times to remove the incompletely hydrolyzed PBPP. The remaining liquid was dried in a vacuum drying oven at 110-130° C. to obtain poly(diphosphonicphosphazene) (PDPP). The yield was 89%.

[0041] Using the same reaction steps, when the extraction was carried out with dichloromethane, benzene, toluene or petroleum ether, the yields were respectively 87%, 83%, 81% and 85%.

[0042] Using the same reaction steps, when reflux was carried out in concentrated hydrochloric acid for 24 h, reduced pressure distillation was carried out at 70° C. and the extraction was carried out with ethyl acetate, the yield was 84%.

[0043] Results of hydrolysis reaction of PBPP with different ester groups are shown in Table 2.

TABLE-US-00001 TABLE 1 Reaction conditions and yields of PBPP prepared by reaction with different triphosphites Triphosphite Charging Time Temperature Reaction Time Yield Trimethyl ester 1 h  90° C. 5 h 87% Tripropyl ester 0.5 h   100° C. 6 h 82% Triethyl ester 0.5 h   110° C. 4 h 89% Triphenyl ester 1 h 100° C. 10 h  73% Triisopropyl ester 2 h 110° C. 6 h 86% Trimethyl ester 1 h 100° C. 9 h 92% Trimethyl ester 0.5 h   120° C. 4 h 85%

TABLE-US-00002 TABLE 2 Yields of PDPP prepared by hydrolyzing PBPP with different ester groups Ester group of PBPP Hydrolysis Time Temperature Yield of PDPP Trimethyl ester 24 h 90° C. 91% Triethyl ester 16 h 85° C. 76% Tripropyl ester 24 h 110° C.  88% Triisopropyl ester 10 h 120° C.  85% Triethyl ester 20 h 95° C. 87% Trimethyl ester 36 h 98° C. 91%

EXAMPLE 4

Preparation of metal poly(diphosphonicphosphazene) Salt

[0044] 2.07 g of the obtained poly(diphosphonicphosphazene) (PDPP) white solid was dissolved in a certain amount of deionized water, and 1.61 g of zirconium oxychloride was dissolved in dilute hydrochloric acid. After the two were respectively dissolved completely, the zirconium oxychloride solution was added dropwise to the PDPP aqueous solution while stirring. After the completion of the dropwise addition, the mixture was stirred at room temperature for 24 h and subjected to suction filtration. The solid was washed with water to neutrality, and dried in a vacuum drying oven at 80-90° C. to obtain 1.93 g of white solid ZrPDPP (0.78). The yield was 76.44%.

[0045] The metal poly(diphosphonicphosphazene) salt (MPDPP) was prepared by using the same method for preparing ZrPDPP above, only except that the zirconium salt solution was replaced with a solution of salt soluble of other metals. MPDPP with different mass proportions can be obtained by controlling the ratio of PDPP to metal salt. The preparation process and property results of products are shown in Table 3.

TABLE-US-00003 TABLE 3 Preparation process conditions of MPDPP compounds Mass Ratio of Metal Type of Metal Ion Salt to PDPP Product Color Yield Mg.sup.2+ 0.78 White 75% Mg.sup.2+ 0.85 White 80% Ca.sup.2+ 0.78 White 76% Zr.sup.4+ 0.45 White 36% Zr.sup.4+ 0.78 White 76% Zr.sup.4+ 0.85 White 84% Zr.sup.4+ 0.92 White 93% Ce.sup.4+ 0.79 Yellow 72% Ce.sup.4+ 0.50 Yellow 56% Ce.sup.4+ 0.85 Yellow 86% Fe.sup.3+ 0.78 White 75% La.sup.3+ 1.41 White 94% Y.sup.3+ 0.78 White 87%

EXAMPLE 5

Compounding Process of Flame Retardant

[0046] MPDPP, PDPP and PBPP were compounded in a certain ratio to obtain the reactive polyurethane flame retardant. PBPP, PDPP and MPDPP were compounded in a mass ratio of 6:1:1-1:3:4. The compounding process included: firstly grinding the MPDPP for 1-2 h, then adding the PDPP according to the ratio and continuing grinding for 0.5-2 h, and after the mixture was ground uniformly, adding the polyPBPP and a suitable solvent and grinding the mixture for 0.5-2 h.

EXAMPLE 6

Use Method of Flame Retardant in Polyurethane and Preparation Process of Polyurethane Product

[0047] The flame retardant in Example 5 was added to the already prepared formula A of polyurethane according to the ratio. The raw materials of the polyurethane were composed of components A and B. In parts by mass, the component A (combined polyether component) included the following ingredients: 50-100 parts of polyether polyol; 0-50 parts of polymer polyol; 0.2-5 parts of catalyst; 1-8 parts of a foaming agent; 0.2-3 parts of foam stabilizer; 0.2-6 parts of a crosslinking agent; 0-10 parts of pore former; and 0.1-20 parts of reactive flame retardant (involved in the invention). The component B (isocyanate component) was polyisocyanate, which may be TDI, MDI, polymeric MDI or modified MDI and a mixture thereof. A mass ratio of A:B was 100:30-100:80.

[0048] The polyether glycol in the formula of the polyurethane had a functionality of 3 and a relative molecular mass of 4000-9000, and a primary hydroxyl content in the terminal hydroxyl was greater than 65%. The polymer polyol was a graft copolymer of polyether polyol and styrene acrylonitrile. The catalyst was tertiary amines or secondary amines. The foaming agent was one or a mixture of several of deionized water, polybasic primary amine and quaternary ammonium carbonate. The foam stabilizer was a polysiloxane-polyether copolymer. The crosslinking agent was an alcohol amine compound. The pore former was a polyether polyol with an EO content of ≥50%.

[0049] For the prepared polyurethane products with the flame retardant added, according to GB/T 2406-1993 and GB/T 2408-2008 respectively, samples were prepared, and tested for flame-retardant properties such as limiting oxygen index and vertical flame test, and according to QB/T 4197-2011, samples were prepared and tested for mechanical properties such as tensile strength and elongation at break. The results are shown in Table 4.

TABLE-US-00004 TABLE 4 Flame-retardant properties of polyurethane using PBPP, PDPP and MPDPP compounded flame retardants Added Limiting Fire Mass Ratio of Compounding Amount Oxygen Index Rating PBPP:PDPP:MPDPP (%) (LOI) (UL-94) EtPBPP:PDPP:MgPDPP 6% 44 Non- MePBPP:PDPP:MgPDP 10%  48 Non- EtPBPP:PDPP:CaPDPP 6% 48 Non- MePBPP:PDPP:CaPDPP 10%  48 Non- EtPBPP:PDPP:ZrPDPP 5% 39 V-0 MePBPP:PDPP:ZrPDPP 5% 42 Non- PrPBPP:PDPP:ZrPDPP 6% 43 Non- EtPBPP:PDPP:CePDPP 9% 44 Non- EtPBPP:PDPP:CePDPP 10%  41 Non- MePBPP:PDPP:CePDPP 8% 42 Non- PrPBPP:PDPP:CePDPP 5% 38 V-0 EtPBPP:PDPP:FePDPP 7% 42 Non- MePBPP:PDPP:FePDPP 10%  45 Non- PrPBPP:PDPP:FePDPP 10%  46 Non- EtPBPP:PDPP:LaPDPP 6% 39 Non- MePBPP:PDPP:LaPDPP 5% 43 Non- EtPBPP:PDPP:YPDPP 7% 44 Non- EtPBPP:PDPP = 1:1 5% 36 V-0 ZrPDPP:PDPP = 1:1 5% 38 V-0 EtPBPP:CePDPP = 1:1 5% 32 V-0 Note: RTHP: esters, Me—methyl; Et—ethyl; Pr—propyl, etc.