A polyurethane rigid foam containing alkylated MOF-808 and a method of making the same

Abstract

The present application relates to the technical field of polyurethane materials, and particularly relates to a polyurethane rigid foam containing alkylated MOF-808 and a preparation method thereof. The polyurethane rigid foam is prepared by addition polymerization reaction and foaming of raw materials containing a polyol composition and a polyisocyanate; wherein the alkylated MOF-808 is added to the polyol composition for mixing; the alkylated MOF-808 is obtained by a silylation reaction of MOF-808 and an alkylsilane reagent. The present application improves the compatibility of MOF-808 and the polyol composition by alkyl modification, and the obtained polyurethane rigid foam has excellent flame retardant performance and thermal insulation performance, and the filler is uniformly and stably dispersed.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, specifically to a rigid polyurethane foam containing alkylated MOF-808 and its preparation method. Background Technology

[0002] Rigid polyurethane foam is a core material in the field of building insulation, especially in the field of interlocking slab building panels, where the requirements for its flame retardant and thermal insulation properties (thermal conductivity) are extremely stringent. To improve flame retardant performance, existing technologies typically add flame retardants such as halophosphates, but the addition of these flame retardants often leads to a decrease in the mechanical properties of the material.

[0003] Metal-organic frameworks (MOFs) exhibit significant application potential in flame retardancy and functional modification due to their high specific surface area, porous structure, and ability to be functionalized. MOF-808, with its three-dimensional porous structure and excellent thermal stability, can serve as a flame-retardant functional carrier. However, when MOF-808 is directly added to polyol compositions (such as combined polyether polyols), noticeable agglomerates are observed in the foam matrix, making uniform dispersion difficult and hindering the full realization of its structural advantages. Therefore, developing a polyurethane rigid foam preparation technology that balances good flame retardancy, low thermal conductivity, and stable filler dispersion is a pressing technical challenge in this field. Summary of the Invention

[0004] This invention provides a polyurethane rigid foam containing alkylated MOF-808 and its preparation method, in order to solve the problem in the prior art that the MOF-808 filler has poor dispersion stability in polyol compositions, which makes it difficult to synergistically improve the flame retardant and thermal insulation properties of polyurethane rigid foam.

[0005] In a first aspect, the present invention provides a rigid polyurethane foam containing alkylated MOF-808, wherein the rigid polyurethane foam is prepared by addition polymerization and foaming of raw materials comprising a polyol composition and a polyisocyanate; wherein the alkylated MOF-808 is added to the polyol composition and mixed; wherein the alkylated MOF-808 is obtained by silanization reaction of MOF-808 with an alkylsilane reagent.

[0006] In this invention, the "polyol composition" (e.g., a combination of polyether polyols, a combination of polyester polyols) refers to a composition premixed from polymeric polyols (polyether polyols and / or polyester polyols), a foaming agent, and optionally flame retardants, catalysts, surfactants, and other auxiliaries, which does not contain alkylated MOF-808. Alkylated MOF-808 is a functional filler added later to the polyol composition.

[0007] In one optional embodiment, the amount of alkylated MOF-808 added is 1% to 5% of the mass of the polyol composition; And / or, the alkylsilane reagent refers to a silane compound capable of reacting with the hydroxyl groups on the surface of MOF-808 and introducing long-chain alkyl groups onto its surface. Preferably, the alkylsilane reagent includes alkyltrichlorosilane and / or alkyltrialkoxysilane; more preferably, the alkyl group in the alkyltrichlorosilane and / or alkyltrialkoxysilane is a long-chain alkyl group with 12 to 20 carbon atoms (preferably a long-chain alkyl group with 16 to 18 carbon atoms). More preferably, the alkylsilane reagent includes, but is not limited to, at least one of octadecyltrichlorosilane, hexadecyltrichlorosilane, octadecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltriethoxysilane, and hexadecyltriethoxysilane.

[0008] In one alternative embodiment, the polyol composition comprises a polymeric polyol and a foaming agent.

[0009] In one optional embodiment, the polymeric polyol includes at least one of polyether polyol and polyester polyol; preferably, the polymeric polyol is a polyether polyol, or a mixture of polyether polyol and polyester polyol.

[0010] And / or, the polyol composition further includes an auxiliary agent; preferably, the auxiliary agent includes at least one of a flame retardant, a catalyst, and a surfactant; And / or, the foaming agent includes at least one of cyclopentane, isopentane, and n-pentane, or a mixture of at least one of cyclopentane, isopentane, and n-pentane with water.

[0011] In one optional embodiment, based on 100 parts by total mass of the polymerized polyol, the amount of flame retardant is 10-20 parts, the amount of catalyst is 0.5-2 parts, the amount of surfactant is 1-3 parts, and the amount of foaming agent is 8-15 parts. For example, the amount of flame retardant can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts; and the amount of catalyst can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, or 1.7 parts. 1.8 parts, 1.9 parts, 2.0 parts; the amount of surfactant can be 1.0 parts, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts, 2.0 parts, 2.2 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.8 parts, 3.0 parts; the amount of foaming agent can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in each of the stated ranges.

[0012] In one optional embodiment, the polyether polyol includes at least one of polyether polyols initiated by sucrose, polyether polyols initiated by sorbitol, polyether polyols initiated by propylene glycol, and polyether polyols initiated by glycerol. And / or, the polyester polyol includes polyester polyols initiated with phthalic anhydride; And / or, the flame retardant includes tri(chloroisopropyl) phosphate (TCPP) and / or triethyl phosphate (TEP); And / or, the catalyst comprises at least one of an amine catalyst, a metal salt catalyst, and water; preferably, the amine catalyst comprises at least one of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, triethylenediamine, TMR-2, and N,N-dimethylbenzylamine; the metal salt catalyst comprises at least one of potassium formate, potassium acetate, and potassium isooctanoate. And / or, the surfactant includes siloxane surfactants, preferably at least one of Evonik B8546, Evonik B84813, Mistex AK88310, and Mistex AK88719.

[0013] In one optional embodiment, the mass ratio of the polyol composition to the polyisocyanate is 1:(1~1.5); for example, the mass ratio can be 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, or 1:1.5. For space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. And / or, the polyisocyanate includes polymeric MDI and / or liquefied modified MDI; preferably, the polyisocyanate is polymeric MDI, more preferably, the polymeric MDI is at least one of Wanhua PM200, Wanhua PM400, and Wanhua PM700.

[0014] In a second aspect, the present invention also provides a method for preparing a rigid polyurethane foam containing alkylated MOF-808 as described in the first aspect, comprising the following steps: (1) Preparation of alkylated MOF-808: MOF-808 was dispersed in an organic solvent, and an alkylsilane reagent was added under a protective atmosphere to carry out a silanization reaction. After post-treatment, alkylated MOF-808 was obtained. (2) Dispersion of alkylated MOF-808: The alkylated MOF-808 is added to the polyol composition and then dispersed to obtain a mixed system in which alkylated MOF-808 is dispersed; (3) Preparation of rigid polyurethane foam: Add polyisocyanate to the mixed system containing alkylated MOF-808 obtained in step (2), mix evenly, pour into a mold, and foam to obtain rigid polyurethane foam.

[0015] In one alternative embodiment, in step (1), the organic solvent includes anhydrous ethanol; And / or, the protective atmosphere includes at least one of nitrogen and argon; And / or, the silanization reaction is carried out at a temperature of 60°C to 70°C for a time of 20h to 24h; for example, the silanization reaction temperature can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, or 70°C; and the time can be 20h, 21h, 22h, 23h, or 24h. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in each of the stated ranges. And / or, the mass ratio of the alkylsilane reagent to MOF-808 is (2~3):1; for example, the mass ratio of the alkylsilane reagent to MOF-808 can be 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, or 3.0:1. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. And / or, the post-processing includes filtration, washing, and drying.

[0016] In one optional embodiment, the mass / volume ratio of MOF-808 to the organic solvent is 1 g:(40~60) mL. For example, the mass / volume ratio of MOF-808 to the organic solvent can be 1 g:40 mL, 1 g:42 mL, 1 g:45 mL, 1 g:48 mL, 1 g:50 mL, 1 g:52 mL, 1 g:55 mL, 1 g:58 mL, or 1 g:60 mL. For space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0017] In one optional embodiment, the washing process includes: repeatedly washing with an organic solvent multiple times, each wash lasting an appropriate time. Preferably, the organic solvent includes anhydrous ethanol; the number of washes is 2 to 5 times, and each wash lasts 5 to 15 minutes; for example, the number of washes can be 2, 3, 4, or 5 times; and the wash time can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, or 15 minutes. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in each of the stated ranges. And / or, the drying process includes: heating and drying under vacuum conditions. Preferably, the drying temperature is 50℃~70℃, and the drying time is 8h~16h. For example, the drying temperature can be 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, or 70℃; the drying time can be 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, or 16h. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in each of the stated ranges. In one alternative implementation, in step (2), the dispersion process is carried out in any of the following ways: A dispersion treatment is performed by simultaneously adding the alkylated MOF-808 and the dispersant to the polyol composition and stirring at 800 r / min to 1200 r / min for 50 min to 90 min. For example, the stirring speed can be 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min, 1050 r / min, 1100 r / min, 1150 r / min, or 1200 r / min, and the time can be 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, or 90 min. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. The multi-stage dispersion process includes: first stirring at 600 r / min to 1000 r / min for 20 min to 40 min, then adding the dispersant and stirring at 800 r / min to 1200 r / min for 30 min to 50 min. For example, the initial stirring speed can be 600 r / min, 650 r / min, 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, 950 r / min, or 1000 r / min, and the time can be 20 min, 22 min, 25 min, 28 min, 30 min, 32 min, 35 min, 38 min, or 40 min; the subsequent stirring speed can be 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min, 1050 r / min, 1100 r / min, 1150 r / min, or 1200 r / min, and the time can be 30 min, 32 min, 35 min, 38 min, 40 min, 42 min, 45 min, 48 min, or 50 min. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in each of the described ranges.

[0018] In one optional embodiment, the dispersant includes, but is not limited to, polyvinylpyrrolidone (PVP); preferably, the amount of the dispersant added is 0.05% to 0.2% of the mass of the polyol composition. For example, the amount of the dispersant added can be 0.05%, 0.06%, 0.08%, 0.10%, 0.12%, 0.14%, 0.15%, 0.16%, 0.18%, or 0.20%. For space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0019] In one optional embodiment, in step (3), the preheating temperature of the mold is 30℃~40℃; for example, the preheating temperature of the mold can be 30℃, 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃, 39℃, or 40℃. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. And / or, the foaming molding temperature is 30℃~40℃, and the time is 0.3h~1h. For example, the foaming molding temperature can be 30℃, 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃, 39℃, or 40℃; and the time can be 0.3h, 0.4h, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, or 1.0h. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in each of the aforementioned ranges.

[0020] In this invention, rigid polyurethane foam can be used in the field of building insulation, and is preferably used in the field of intermittent slab building panels.

[0021] The technical solution of this invention has the following advantages: 1. The polyurethane rigid foam containing alkylated MOF-808 provided by the present invention is prepared by silanizing MOF-808 with an alkylsilane reagent to disperse the alkylated MOF-808 in a polyol composition, followed by addition polymerization with a polyisocyanate and foaming. Because the alkylation modification effectively reduces the surface polarity of MOF-808, it significantly improves its compatibility with the polyol composition, thereby solving the problem of poor dispersion stability of MOF-808 filler in the prior art and avoiding foam structure defects caused by agglomeration. Simultaneously, the uniformly dispersed alkylated MOF-808, on the one hand, utilizes its porous structure to promote the release of flame-retardant gases and catalyze the formation of a dense carbon layer, effectively isolating heat and oxygen; on the other hand, by reducing the heat conduction path and the low thermal conductivity of the long-chain alkyl-modified layer, the limiting oxygen index of the polyurethane rigid foam is increased by more than 20%, and the thermal conductivity is reduced by more than 10%, achieving a synergistic improvement in flame retardant and thermal insulation performance.

[0022] 2. The preparation method provided by the present invention employs a multi-stage dispersion process. First, alkylated MOF-808 is added to the polyol composition for pre-dispersion, and then a dispersant is added for secondary dispersion. This ensures that the alkylated MOF-808 is uniformly and stably dispersed in the polyol composition, further avoiding the problem of filler agglomeration. At the same time, this multi-stage dispersion process is highly compatible with the existing polyurethane rigid foam production process, requiring no additional complex equipment investment. The process is simple, the cost is controllable, and it is suitable for large-scale industrial production. Detailed Implementation

[0023] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0024] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0025] The raw materials used in the following examples and comparative examples are from the following sources: MOF-808: Purchased from Aladdin Reagents (Shanghai) Co., Ltd.; Combined polyether polyols: obtained by uniformly mixing the following components in parts by mass: 60 parts of sucrose-based polyether polyol (hydroxyl value 420 mgKOH / g), 40 parts of propylene glycol-based polyether polyol (hydroxyl value 260 mgKOH / g), 15 parts of tri(chloroisopropyl) phosphate, 1.2 parts of pentamethyldiethylenetriamine, 2.0 parts of siloxane surfactant B8546, and 12 parts of cyclopentane; Among them, the polyether polyol was synthesized by our company. The specific preparation method of sucrose-starting polyether polyol is as follows: using sucrose as the initiator and potassium hydroxide as the catalyst, the mixture is dehydrated under vacuum at 105℃ under nitrogen protection, polymerized by dropwise addition of propylene oxide at 110~120℃, and aged at this temperature for 2 hours. After the reaction is complete, the temperature is lowered to 80℃, deionized water is added and stirred for washing, and the pH of the system is neutralized to 6.5-7.0 with phosphoric acid; then the temperature is raised to 110℃, and dehydrated under vacuum at -0.095MPa for 2 hours. Finally, the mixture is filtered to remove salts and impurities to obtain the finished polyether polyol. The specific preparation method of propylene glycol-based polyether polyol is as follows: using propylene glycol as the initiator and propylene oxide as the monomer, KOH catalysis, vacuum dehydration at 100℃ under nitrogen protection, polymerization with propylene oxide added dropwise at 115℃, and curing at this temperature for 1.5h. After the reaction, the temperature is lowered to 80℃, deionized water is added and stirred for washing, and the solution is neutralized with phosphoric acid to pH=7.0; then the temperature is raised to 110℃, vacuum dehydration is carried out at -0.095MPa for 2h, and the final product is obtained after filtration to remove salt residue and impurities. Tris(chloroisopropyl) phosphate, purchased from Zhejiang Wansheng Co., Ltd.; Pentamethyldiethylenetriamine was purchased from Shanghai Demao Chemical Co., Ltd. The siloxane surfactant B8546 was purchased from Evonik Chemicals. PM-200: Polymer MDI, Wanhua Chemical Group Co., Ltd. Alkylsilane reagents: purchased from Sinopharm Chemical Reagent Co., Ltd.; PVP: Polyvinylpyrrolidone, K30, purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0026] Example 1 This invention provides a method for preparing rigid polyurethane foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.5g of octadecyltrichlorosilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0027] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 2.0g of alkylated MOF-808, stir at 800 rpm for 30 minutes, then add 0.1g of polyvinylpyrrolidone dispersant, and continue stirring at 1000 rpm for 40 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0028] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35°C, place in a constant temperature oven at 35°C for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0029] Example 2 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.0g of hexadecyltrichlorosilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0030] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 1.5g of alkylated MOF-808, stir at 800 rpm for 30 minutes, then add 0.1g of polyvinylpyrrolidone dispersant, and continue stirring at 1000 rpm for 40 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0031] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35°C, place in a constant temperature oven at 35°C for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0032] Example 3 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.5g of octadecyltrichlorosilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0033] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 2.5g of alkylated MOF-808, stir at 800 rpm for 30 minutes, then add 0.1g of polyvinylpyrrolidone dispersant, and continue stirring at 1000 rpm for 40 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0034] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35°C, place in a constant temperature oven at 35°C for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0035] Example 4 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.5g of octadecyltrimethoxysilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0036] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 3.0g of alkylated MOF-808, stir at 800 rpm for 30 minutes, then add 0.1g of polyvinylpyrrolidone dispersant, and continue stirring at 1000 rpm for 40 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0037] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35°C, place in a constant temperature oven at 35°C for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0038] Example 5 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 40mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.0g of hexadecyltrimethoxysilane, heat to 60℃, and stir at 500 rpm for 24 hours. After the reaction is complete, filter the mixture and wash it 5 times with anhydrous ethanol (5 minutes each time). Place the filter cake in a vacuum drying oven at 50℃ and dry it for 16 hours to obtain alkylated MOF-808.

[0039] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 1.0g of alkylated MOF-808, stir at 600 rpm for 40 minutes, then add 0.05g of polyvinylpyrrolidone dispersant, and continue stirring at 800 rpm for 50 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0040] (3) Preparation of rigid polyurethane foam: Add 100g of PM-200 polymeric MDI (the mass ratio of combined polyether polyol and polyisocyanate is 1:1) to the mixed system with alkylated MOF-808 dispersed in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 30°C, place in a constant temperature oven at 30°C for 1 hour to foam and form, and open the mold to obtain rigid polyurethane foam.

[0041] Example 6 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 60mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 3.0g of octadecyltriethoxysilane, heat to 70℃, and stir at 500 rpm for 20 hours. After the reaction is complete, filter the mixture and wash it twice with anhydrous ethanol (15 minutes each time). Place the filter cake in a vacuum drying oven at 70℃ and dry it for 8 hours to obtain alkylated MOF-808.

[0042] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 5.0g of alkylated MOF-808, stir at 1000 rpm for 20 minutes, then add 0.2g of polyvinylpyrrolidone dispersant, and continue stirring at 1200 rpm for 30 minutes to obtain a uniformly dispersed mixed system without agglomerated particles.

[0043] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI (the mass ratio of combined polyether polyol and polyisocyanate is 1:1.5) to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 40°C, place in a constant temperature oven at 40°C for foaming and molding for 0.3 hours, and open the mold to obtain rigid polyurethane foam.

[0044] Example 7 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808. The only difference from Example 1 is that a single-stage dispersion process is used instead of a multi-stage dispersion process; that is, the multi-stage dispersion step of first stirring, then adding the dispersant, and then stirring again is omitted. Other conditions are the same as in Example 1. The specific steps are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.5g of octadecyltrichlorosilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0045] (2) Dispersion of alkylated MOF-808: Weigh 100g of combined polyether polyol, add 2.0g of alkylated MOF-808 and 0.1g of polyvinylpyrrolidone dispersant, stir at 1000 rpm for 70 minutes to obtain a mixed system.

[0046] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixture obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35℃, place in a 35℃ constant temperature oven for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0047] Example 8 This embodiment provides a method for preparing polyurethane rigid foam containing alkylated MOF-808, the specific steps of which are as follows: (1) Preparation of alkylated MOF-808: Weigh 1g of MOF-808 and add it to 50mL of anhydrous ethanol. Disperse the mixture for 30 minutes using an ultrasonic device with a frequency of 40kHz and a power of 200W. Purge the air from the system with nitrogen and maintain a protective atmosphere. Add 2.5g of octadecyltrichlorosilane, heat to 65℃, and stir at 500 rpm for 22 hours. After the reaction is complete, filter the mixture and wash it three times with anhydrous ethanol (10 minutes each time). Place the filter cake in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain alkylated MOF-808.

[0048] (2) Dispersion of alkylated MOF-808: Weigh 100g of the combined polyether and polyester polyol (obtained by uniformly mixing the following components in parts by mass: 60 parts of sucrose-starting polyether polyol, 40 parts of phthalic anhydride-starting polyester polyol, 15 parts of tri(chloroisopropyl) phosphate, 1.2 parts of pentamethyldiethylenetriamine, 2.0 parts of siloxane surfactant B8546, and 12 parts of cyclopentane), add 2.0g of alkylated MOF-808, stir at 800 rpm for 30 minutes, then add 0.1g of polyvinylpyrrolidone dispersant, and continue stirring at 1000 rpm for 40 minutes to obtain a mixed system. The specific preparation method of the phthalic anhydride-starting polyester polyol is as follows: using phthalic anhydride and diethylene glycol as raw materials, gradually raise the temperature to 180~220℃ under nitrogen protection to carry out the esterification reaction, keep the reaction temperature for 4h, and continuously remove the water generated in the reaction. After the reaction is complete, the temperature is lowered to 80℃, deionized water is added and stirred for washing, and the pH of the system is neutralized to 7.0 with phosphoric acid; then the temperature is raised to 110℃ and dehydrated under a vacuum of -0.095MPa for 2 hours. Finally, the product polyester polyol is obtained by filtration to remove impurities.

[0049] (3) Preparation of rigid polyurethane foam: Add 150g of PM-200 polymeric MDI to the mixed system containing alkylated MOF-808 obtained in step (2), stir at 2000 rpm for 10 seconds to mix evenly, pour into a metal mold preheated to 35°C, place in a constant temperature oven at 35°C for foaming and molding for 0.5 hours, and open the mold to obtain rigid polyurethane foam.

[0050] Comparative Example 1 This comparative example provides a method for preparing rigid polyurethane foam, which differs from Example 1 only in that MOF-808 material is not added, i.e. steps (1) and (2) are not performed, and other conditions are the same as in Example 1.

[0051] Comparative Example 2 This comparative example provides a method for preparing rigid polyurethane foam, which differs from Example 1 only in that unmodified MOF-808 is used, that is, the alkylation modification reaction in step (1) is not carried out, and other conditions are the same as in Example 1.

[0052] Test case The performance of the rigid polyurethane foams prepared in Examples 1 to 8 and Comparative Examples 1 to 2 was tested. The test results are shown in Table 1 below. The test methods are as follows: (1) Limiting Oxygen Index (LOI) test: The test was conducted in accordance with GB / T 2406.2-2009 standard.

[0053] (2) Thermal conductivity test: The test was conducted in accordance with ASTM C518 standard.

[0054] (3) Observation of filler dispersibility: The morphology of the cross-section of the polyurethane rigid foam prepared in each example and comparative example was observed by scanning electron microscopy (SEM) to observe the dispersion state of the filler in the foam matrix.

[0055] Table 1 Test results of each embodiment and comparative example

[0056] According to the test results above, the limiting oxygen index of Examples 1-8 of this invention is all above 25.0%, and the thermal conductivity is all below 0.0196 W / (m·K), indicating uniform filler dispersion. Comparative Example 1, without MOF-808, has a limiting oxygen index of only 20.5% and a thermal conductivity of 0.0215 W / (m·K). Comparative Example 2, using unmodified MOF-808, has a limiting oxygen index of only 21.8% and a thermal conductivity of 0.0210 W / (m·K), and exhibits significant agglomeration. This indicates that alkylation modification effectively improves the compatibility of MOF-808 with the polyol composition, achieving a synergistic improvement in flame retardant and thermal insulation properties.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rigid polyurethane foam containing alkylated MOF-808, characterized in that, The polyurethane rigid foam is prepared by addition polymerization and foaming of raw materials comprising a polyol composition and a polyisocyanate; wherein, alkylated MOF-808 is added to the polyol composition and mixed; the alkylated MOF-808 is obtained by silanization reaction of MOF-808 with an alkylsilane reagent.

2. The rigid polyurethane foam containing alkylated MOF-808 according to claim 1, characterized in that, The amount of alkylated MOF-808 added is 1% to 5% of the mass of the polyol composition; And / or, the alkylsilane reagent includes alkyltrichlorosilane and / or alkyltrialkoxysilane; preferably, the alkyl group in the alkyltrichlorosilane and / or alkyltrialkoxysilane is a long-chain alkyl group with 12 to 20 carbon atoms; more preferably, the alkyl group in the alkyltrichlorosilane and / or alkyltrialkoxysilane is a long-chain alkyl group with 16 to 18 carbon atoms.

3. The rigid polyurethane foam containing alkylated MOF-808 according to claim 1 or 2, characterized in that, The polyol composition includes a polymeric polyol and a foaming agent.

4. The rigid polyurethane foam containing alkylated MOF-808 according to claim 3, characterized in that, The polymeric polyol includes at least one of polyether polyol and polyester polyol; preferably, the polymeric polyol is a polyether polyol, or a mixture of polyether polyol and polyester polyol. And / or, the polyol composition further includes an auxiliary agent; preferably, the auxiliary agent includes at least one of a flame retardant, a catalyst, and a surfactant; And / or, the foaming agent includes at least one of cyclopentane, isopentane, and n-pentane, or a mixture of at least one of cyclopentane, isopentane, and n-pentane with water.

5. The rigid polyurethane foam containing alkylated MOF-808 according to claim 4, characterized in that, The polyether polyol includes at least one of the following: polyether polyols initiated by sucrose, polyether polyols initiated by sorbitol, polyether polyols initiated by propylene glycol, and polyether polyols initiated by glycerol. And / or, the polyester polyol includes polyester polyols initiated with phthalic anhydride; And / or, the flame retardant comprises tri(chloroisopropyl) phosphate and / or triethyl phosphate; And / or, the catalyst includes at least one of an amine catalyst, a metal salt catalyst, and water; And / or, the surfactant includes siloxane surfactants.

6. The rigid polyurethane foam containing alkylated MOF-808 according to claim 1 or 2, characterized in that, The mass ratio of the polyol composition to the polyisocyanate is 1:(1~1.5); And / or, the polyisocyanate comprises polymeric MDI and / or liquefied modified MDI.

7. A method for preparing a rigid polyurethane foam containing alkylated MOF-808 as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Preparation of alkylated MOF-808: MOF-808 was dispersed in an organic solvent, and an alkylsilane reagent was added under a protective atmosphere to carry out a silanization reaction. After post-treatment, alkylated MOF-808 was obtained. (2) Dispersion of alkylated MOF-808: The alkylated MOF-808 is added to the polyol composition and then dispersed to obtain a mixed system in which alkylated MOF-808 is dispersed; (3) Preparation of rigid polyurethane foam: Add polyisocyanate to the mixed system containing alkylated MOF-808 obtained in step (2), mix evenly, pour into a mold, and foam to obtain rigid polyurethane foam.

8. The preparation method according to claim 7, characterized in that, In step (1), the organic solvent includes anhydrous ethanol; And / or, the protective atmosphere includes at least one of nitrogen and argon; And / or, the silanization reaction is carried out at a temperature of 60°C to 70°C for a time of 20 to 24 hours; And / or, the mass ratio of the alkylsilane reagent to MOF-808 is (2~3):1; And / or, the post-processing includes filtration, washing, and drying.

9. The preparation method according to claim 7 or 8, characterized in that, In step (2), the dispersion process is carried out in any of the following ways: Dispersion treatment: The alkylated MOF-808 and the dispersant are added to the polyol composition at the same time, and stirred at 800 r / min to 1200 r / min for 50 min to 90 min; The multi-stage dispersion process includes: first stirring at 600 r / min to 1000 r / min for 20 min to 40 min, then adding the dispersant and stirring at 800 r / min to 1200 r / min for 30 min to 50 min.

10. The preparation method according to claim 7 or 8, characterized in that, In step (3), the preheating temperature of the mold is 30℃~40℃; And / or, the foaming molding temperature is 30℃~40℃, and the time is 0.3h~1h.

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