Fire-retardant polyurethane foam and preparation method thereof

Abstract

The present invention relates to the technical field of polyurethane foams, and discloses a fire-retardant polyurethane foam and a preparation method thereof. The A component of the polyurethane foam of the present invention is: 100 parts by weight of polyether polyol, 25-50 parts by weight of a flame retardant chain extender, etc.; the B component is 62-86 parts by weight of an isocyanate compound. The flame retardant chain extender contains multiple polymerization sites, which increases the crosslinking density of the polyurethane molecular chain and forms a stable crosslinked network. At the same time, it contains a siloxane structural unit with structural stability, so that the polyurethane foam has higher compressive strength. The flame retardant chain extender contains a phosphate flame retardant group, which forms a phosphorus-silicon flame retardant system with the siloxane structure, reduces the peak combustion heat release rate, total heat release, and total smoke release of the foam, and has excellent fire retardant properties.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane foam, in particular to a fire-resistant and flame-retardant foamed polyurethane and a preparation method thereof. Background Art

[0002] Polyurethane foam offers excellent thermal insulation, sound insulation, waterproofing, and corrosion resistance, making it widely used in construction, transportation, and refrigeration equipment insulation. Polyurethane foam is typically produced through polymerization and foaming of polyols, isocyanate compounds, chain extenders, and blowing agents. Traditional polyurethane foam suffers from low compressive strength and flammability, limiting its practical application. Chain extenders significantly impact the properties of polyurethane foam. Common chain extenders include 1,4-butanediol, diethanolamine, trimethylolpropane, silicone chain extenders, and phosphate ester polyol chain extenders.

[0003] Adding phosphorus-, nitrogen-, and silicon-based flame retardants to polyurethane foam can improve its flame retardancy. Chinese patent CN113817170B discloses a phosphorus-nitrogen-silicon intumescent flame retardant, its preparation method, and its use in rigid polyurethane foam. The macromolecular phosphorus-nitrogen-silicon flame retardant, obtained by reacting an isocyanate alkylalkoxysilane with tris(2-hydroxyethyl)isocyanurate and phosphorus-containing dichloride, can improve the heat resistance, flame retardancy, and corrosion resistance of polyurethane foam. However, the phosphorus-nitrogen-silicon flame retardant does not improve mechanical properties such as compressive strength of the polyurethane foam. Summary of the Invention

[0004] (1) Technical problems solved:

[0005] In view of the deficiencies in the prior art, the present invention provides a fire-retardant polyurethane foam and a preparation method thereof, which solves the problems of poor flame retardancy and low mechanical strength of polyurethane foam.

[0006] (2) Technical solution: A fire-retardant polyurethane foam and a preparation method thereof, the fire-retardant polyurethane foam comprising component A and component B; component A comprising: 100 parts by weight of a polyether polyol, 0.6-0.8 parts by weight of an organic amine catalyst, 0.4-0.7 parts by weight of an organic tin catalyst, 2.8-3.6 parts by weight of deionized water, 1.8-2.5 parts by weight of a foam stabilizer, and 25-50 parts by weight of a flame retardant chain extender; component B comprising 62-86 parts by weight of an isocyanate compound.

[0007] The preparation method of the fire-retardant polyurethane foam comprises the following steps: mixing a polyether polyol, an organic amine catalyst, an organic tin catalyst, deionized water, a foam stabilizer, and a flame retardant chain extender to obtain component A; then mixing the component A with the isocyanate compound of component B for 8-12 seconds, quickly pouring the mixture into a mold, foaming the mixture at 20-30°C for 10-20 minutes, and then aging the mixture at 60-80°C for 12-18 hours to obtain the fire-retardant polyurethane foam.

[0008] Furthermore, the polyether polyol is polytetramethylene ether glycol or polyether polyol N220.

[0009] Furthermore, the organic amine catalyst is triethylenediamine.

[0010] Furthermore, the foam stabilizer is an organosilicon foam stabilizer.

[0011] Furthermore, the organotin catalyst is dibutyltin dilaurate or stannous octoate.

[0012] Furthermore, the isocyanate compound is any one or a combination of isophorone diisocyanate, toluene-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, and polyphenylpolymethylene polyisocyanate.

[0013] Furthermore, the preparation method of the flame retardant chain extender includes: adding a solvent, 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, and 4-aminophenyl diethyl phosphate in a molar ratio of 1:(2.2-2.6) to a reaction vessel, stirring and reacting at 40-55°C for 7-10 hours, rotary evaporation, and separation of the product by silica gel column chromatography, with the eluent being a mixed solution of dichloromethane and methanol, to obtain the flame retardant chain extender. The reaction formula is:

[0014] .

[0015] Furthermore, the solvent is tetrahydrofuran or isopropanol.

[0016] (III) Beneficial Technical Effects: The present invention reacts 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane and 4-aminophenyl diethyl phosphate to obtain a flame retardant chain extender containing multiple hydroxyl and imino polymerization sites. The flame retardant chain extender then undergoes a cross-linking polymerization reaction with an isocyanate compound and a polyether polyol, and foaming is performed to obtain a flame-retardant foamed polyurethane. The flame retardant chain extender contains multiple polymerization sites, which increases the cross-linking density of the polyurethane molecular chain, forming a stable cross-linked network, which is beneficial for improving the mechanical strength of the polyurethane foam. At the same time, the flame retardant chain extender contains structurally stable siloxane structural units, which, when introduced into the polyurethane molecular chain, can further improve the mechanical properties of the polyurethane foam and provide higher compressive strength.

[0017] The flame retardant chain extender of the present invention contains a phosphate flame retardant group, which forms a phosphorus-silicon flame retardant system with a siloxane structure. When the foam burns, the phosphate group is pyrolyzed to generate a phosphoric acid substance, which promotes the dehydration of the foam into carbon. The siloxane structure is pyrolyzed to form an inorganic silicon-oxygen substance, which is compounded with the carbon layer to form a strong and stable carbon-silicon layer, which can isolate oxygen and inhibit smoke emission, thereby reducing the peak value of the combustion heat release rate, the total heat release and the total smoke release of the foam, and has excellent fire retardant properties. DETAILED DESCRIPTION

[0018] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0019] The fire-retardant polyurethane foam provided by the present invention comprises a component A and a component B; the component A comprises: 100 parts by weight of a polyether polyol, 0.6-0.8 parts by weight of an organic amine catalyst, 0.4-0.7 parts by weight of an organic tin catalyst, 2.8-3.6 parts by weight of deionized water, 1.8-2.5 parts by weight of a foam stabilizer, and 25-50 parts by weight of a flame retardant chain extender; and the component B comprises 62-86 parts by weight of an isocyanate compound.

[0020] The preparation method of the fire-retardant polyurethane foam comprises the following steps: mixing a polyether polyol, an organic amine catalyst, an organic tin catalyst, deionized water, a foam stabilizer, and a flame retardant chain extender to obtain component A; then mixing the component A with the isocyanate compound of component B for 8-12 seconds, quickly pouring the mixture into a mold, foaming the mixture at 20-30°C for 10-20 minutes, and then aging the mixture at 60-80°C for 12-18 hours to obtain the fire-retardant polyurethane foam.

[0021] Furthermore, the polyether polyol is polytetramethylene ether glycol or polyether polyol N220.

[0022] Furthermore, the organic amine catalyst is triethylenediamine.

[0023] Furthermore, the foam stabilizer is an organosilicon foam stabilizer.

[0024] Furthermore, the organotin catalyst is dibutyltin dilaurate or stannous octoate.

[0025] Furthermore, the isocyanate compound is any one or a combination of isophorone diisocyanate, toluene-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, and polyphenylpolymethylene polyisocyanate.

[0026] Furthermore, the preparation method of the flame retardant chain extender includes: adding a solvent, 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, and 4-aminophenyl diethyl phosphate in a molar ratio of 1:(2.2-2.6) to a reaction vessel, stirring and reacting at 40-55°C for 7-10 hours, rotary evaporation, and separation of the product by silica gel column chromatography, with the eluent being a mixed solution of dichloromethane and methanol, to obtain the flame retardant chain extender. The reaction formula is:

[0027] .

[0028] Furthermore, the solvent is tetrahydrofuran or isopropanol.

[0029] The organosilicon foam stabilizer in the following specific embodiments is silicone oil 8110, purchased from Shandong Shengteng Chemical Co., Ltd. The palladium carbon catalyst, with a Pd content of 10%, was purchased from Maoming Xiongda Chemical Co., Ltd.

[0030] Prepare 4-aminophenyl diethyl phosphate according to the method of the journal Bioorganic & Medicinal Chemistry Letters 13 (2003) 1623-1626, "Structure-activity relationship on human serum paraoxonase (PON1) using substrate analogues and inhibitors". Add 160 mL of methanol and 15 g of 4-nitrophenyl diethyl phosphate (structural formula: ), 0.14g palladium carbon catalyst, introduce pressurized hydrogen and control the pressure to 0.3MPa, stir and react at 40℃ for 24h, filter and rotary evaporate the filtrate, separate the product by silica gel column chromatography, eluent is a mixed solution of ethyl acetate and petroleum ether, and obtain 4-aminophenyl diethyl phosphate, the structural formula is .

[0031] Example 1

[0032] (1) Add 200 mL of tetrahydrofuran solvent, 50 mmol of 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, and 120 mmol of 4-aminophenyl diethyl phosphate to a reaction vessel, stir and react at 55°C for 7 h, rotary evaporation, and separation of the product by silica gel column chromatography. The eluent is a mixed solution of dichloromethane and methanol to obtain a flame retardant chain extender.

[0033] (2) 100 g of polyether polyol N220 (average molecular weight of about 2000), 0.8 g of triethylenediamine, 0.4 g of dibutyltin dilaurate, 3.3 g of deionized water, 2.5 g of silicone foam stabilizer, and 25 g (29.34 mmol) of flame retardant chain extender were stirred and mixed to obtain component A.

[0034] (3) 29 g of isophorone diisocyanate and 38 g of polyphenyl polymethylene polyisocyanate were mixed to obtain component B, which was stirred with component A for 8 seconds, quickly poured into a mold, foamed at 20°C for 20 minutes, and then aged at 60°C for 18 hours to obtain a fire-retardant foamed polyurethane.

[0035] Example 2

[0036] (1) Add 200 mL of tetrahydrofuran solvent, 50 mmol of 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, and 130 mmol of 4-aminophenyl diethyl phosphate to a reaction vessel, stir and react at 50°C for 7 h, rotary evaporation, and separation of the product by silica gel column chromatography. The eluent is a mixed solution of dichloromethane and methanol to obtain a flame retardant chain extender.

[0037] (2) 100 g of polyether polyol N220 (average molecular weight of about 2000), 0.8 g of triethylenediamine, 0.5 g of stannous octoate, 3.6 g of deionized water, 1.8 g of silicone foam stabilizer, and 40 g of flame retardant chain extender were stirred and mixed to obtain component A.

[0038] (3) 24 g of toluene-2,4-diisocyanate and 42 g of polyphenyl polymethylene polyisocyanate were mixed to obtain component B, which was stirred with component A for 8 seconds, quickly poured into a mold, foamed at 20°C for 20 minutes, and then aged at 80°C for 12 hours to obtain a fire-retardant foamed polyurethane.

[0039] Example 3

[0040] (1) Add 150 mL of isopropanol solvent, 50 mmol of 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, and 110 mmol of 4-aminophenyl diethyl phosphate to a reaction vessel, stir and react at 40°C for 10 h, rotary evaporate, and separate the product by silica gel column chromatography. The eluent is a mixed solution of dichloromethane and methanol to obtain a flame retardant chain extender.

[0041] (2) 100 g of polytetramethylene ether glycol (average molecular weight of about 2000), 0.6 g of triethylenediamine, 0.7 g of dibutyltin dilaurate, 2.8 g of deionized water, 1.8 g of silicone foam stabilizer, and 50 g of flame retardant chain extender were stirred and mixed to obtain component A.

[0042] (3) Component B was obtained by mixing 39 g of diphenylmethane-4,4'-diisocyanate and 47 g of polyphenylmethylene polyisocyanate. The component B was stirred with component A for 12 seconds, quickly poured into a mold, foamed at 30°C for 10 minutes, and then aged at 70°C for 18 hours to obtain a fire-retardant foamed polyurethane.

[0043] Comparative Example 1

[0044] According to the method of the journal "Polymer Materials Science and Engineering" Volume 31, Issue 6, June 2015, the document "Synthesis of Flame Retardant Polyols and Their Application in Polyurethane Foams", diethylene glycol and phenylphosphinoyl dichloride were used as raw materials to prepare flame retardant polyols. The structural formula is .

[0045] (1) 100 g of polyether polyol N220 (average molecular weight of about 2000), 0.8 g of triethylenediamine, 0.4 g of dibutyltin dilaurate, 3.3 g of deionized water, 2.5 g of silicone foam stabilizer, and 9.80 g (29.34 mmol) of flame retardant polyol were stirred and mixed to obtain component A.

[0046] (2) 29 g of isophorone diisocyanate and 38 g of polyphenyl polymethylene polyisocyanate were mixed to obtain component B, which was stirred with component A for 8 seconds, quickly poured into a mold, foamed at 20°C for 20 minutes, and then aged at 60°C for 18 hours to obtain a fire-retardant foamed polyurethane.

[0047] Comparative Example 2

[0048] (1) 100 g of polyether polyol N220 (average molecular weight of about 2000), 0.8 g of triethylenediamine, 0.4 g of dibutyltin dilaurate, 3.3 g of deionized water, 2.5 g of silicone foam stabilizer, and 8.16 g (29.34 mmol) of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane (CAS registration number 5931-17-9) were stirred and mixed to obtain component A.

[0049] (2) 29 g of isophorone diisocyanate and 38 g of polyphenyl polymethylene polyisocyanate were mixed to obtain component B, which was stirred with component A for 8 seconds, quickly poured into a mold, foamed at 20°C for 20 minutes, and then aged at 60°C for 18 hours to obtain a fire-retardant foamed polyurethane.

[0050] Comparative Example 3

[0051] (1) 100 g of polyether polyol N220 (average molecular weight of about 2000), 0.8 g of triethylenediamine, 0.4 g of dibutyltin dilaurate, 3.3 g of deionized water, 2.5 g of silicone foam stabilizer, and 3.08 g (29.34 mmol) of diethanolamine were stirred and mixed to obtain component A.

[0052] (2) 29 g of isophorone diisocyanate and 38 g of polyphenyl polymethylene polyisocyanate were mixed to obtain component B, which was stirred with component A for 8 seconds, quickly poured into a mold, foamed at 20°C for 20 minutes, and then aged at 60°C for 18 hours to obtain a fire-retardant foamed polyurethane.

[0053] The compression properties of polyurethane foam are tested according to GB / T 8813-2020.

[0054] The combustion performance of polyurethane foam was tested using a cone calorimeter with a heat radiation power of 35kW / m 2 .

[0055] Table 1 Performance test of foamed polyurethane

[0056]

[0057] After testing, Examples 1-3 added a flame retardant chain extender when preparing the foamed polyurethane. The flame retardant chain extender contains multiple hydroxyl and imino polymerization sites, which undergo cross-linking polymerization reactions with isocyanate compounds and polyether polyols, thereby increasing the cross-linking density of the polyurethane molecular chain and forming a stable cross-linking network, which is beneficial to improving the mechanical strength of the polyurethane foam. At the same time, the flame retardant chain extender contains a structurally stable siloxane structural unit, which is introduced into the polyurethane molecular chain to further improve the mechanical properties of the polyurethane foam and show higher compressive strength. In addition, the flame retardant chain extender contains a phosphate flame retardant group, which forms a phosphorus-silicon flame retardant system with the siloxane structure. When the foam burns, the phosphate group pyrolyzes to form a phosphoric acid substance, which promotes the dehydration of the foam into carbon. The siloxane structure pyrolyzes to form an inorganic silicon-oxygen substance, which is compounded with the carbon layer to form a strong and stable carbon-silicon layer, which can isolate oxygen and inhibit smoke emission, thereby reducing the peak heat release rate, total heat release, and total smoke release of the foam, showing good fire retardant properties.

[0058] Compared with Example 1, Comparative Example 1 uses a flame retardant polyol as a chain extender, which contains only two hydroxyl polymerization sites and can only undergo linear polymerization reactions with isocyanate compounds and polyether polyols. It cannot form a cross-linked network, which is not conducive to increasing the cross-linking density of the polyurethane molecular chain. It also does not contain a siloxane structure, resulting in a lower compressive strength of the polyurethane foam. At the same time, the peak combustion heat release rate, total heat release and total smoke release are higher than those in Example 1.

[0059] Comparative Example 2 uses 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, which contains only two hydroxyl polymerization sites and cannot undergo cross-linking polymerization reaction with isocyanate compounds and polyether polyols. It also does not contain phosphate flame retardant groups, resulting in low compressive strength, large peak combustion heat release rate, total heat release and total smoke release, and poor mechanical strength and flame retardant properties.

[0060] Comparative Example 3 uses diethanolamine containing multiple hydroxyl groups and imino groups as a chain extender. It does not contain a phosphate group or a siloxane structure, resulting in a lower compressive strength than that of Example 1, and a larger peak value of the combustion heat release rate, the total heat release amount, and the total smoke release amount, resulting in poor flame retardant properties.

[0061] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-described detailed process flow, that is, it does not mean that the present invention must rely on the above-described detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A fire-retardant polyurethane foam, comprising component A and component B; Component A: 100 parts by weight of polyether polyol, 0.6-0.8 parts by weight of an organic amine catalyst, 0.4-0.7 parts by weight of an organic tin catalyst, 2.8-3.6 parts by weight of deionized water, 1.8-2.5 parts by weight of a foam stabilizer, 25-50 parts by weight of a flame retardant chain extender; the polyether polyol is polytetramethylene ether glycol or polyether polyol N220; The organic amine catalyst is triethylenediamine; the foam stabilizer is a silicone foam stabilizer; Component B is 62-86 parts by weight of an isocyanate compound; The isocyanate compound is any one or a combination of isophorone diisocyanate, toluene-2,4-diisocyanate, diphenylmethane-4,4' diisocyanate, and polyphenyl polymethylene polyisocyanate. The preparation method of the flame retardant chain extender comprises: A solvent, 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane and 4-aminophenyl diethyl phosphate in a molar ratio of 1:(2.2-2.6) were added to a reaction container, stirred for reaction, and then rotary evaporated. The product was separated by silica gel column chromatography to obtain a flame retardant chain extender.

2. The fire-retardant polyurethane foam according to claim 1, characterized in that: The organic tin catalyst is dibutyltin dilaurate or stannous octoate.

3. The fire-retardant polyurethane foam according to claim 1, characterized in that: In the preparation method of the flame retardant chain extender, the solvent is tetrahydrofuran or isopropyl alcohol.

4. The fire-retardant polyurethane foam according to claim 1, characterized in that: The reaction temperature is 40-55° C., and the reaction time is 7-10 h.

5. A method for preparing the fire-retardant polyurethane foam according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: mixing polyether polyol, organic amine catalyst, organic tin catalyst, deionized water, foam stabilizer and flame retardant chain extender to obtain component A; then mixing the component A with component B, an isocyanate compound, pouring the mixture into a mold, foaming and aging the mixture to obtain a fire-retardant foamed polyurethane.

6. The method for preparing the fire-retardant polyurethane foam according to claim 5, wherein: The foaming is carried out at 20-30° C. for 10-20 minutes.

7. The method for preparing the fire-retardant polyurethane foam according to claim 5, wherein: The aging is carried out at 60-80° C. for 12-18 hours.

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