A castor oil-based phosphate ester flame-retardant polyol, a method for preparing the same, and a composite flame-retardant polyurethane rigid foam prepared using the same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG HUANGMA TECH CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-06-09
Smart Images
Figure CN122167474A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of rigid polyurethane foam materials, specifically relating to a castor oil-based phosphate ester flame-retardant polyol, its preparation method, and a composite flame-retardant rigid polyurethane foam prepared using the same. Background Technology
[0002] Rigid polyurethane foam (RPUF) boasts advantages such as light weight, high specific strength, excellent thermal insulation, and strong mechanical properties, leading to its widespread application in construction, transportation, and other aspects of daily life. However, its unique porous structure makes it highly flammable, with a limiting oxygen index (LOI) typically below 19 vol%. The toxic fumes produced during combustion negatively impact the environment and human health, severely limiting its applications. Flame retardant methods for RPUF primarily involve the use of additive flame retardants and reactive flame retardants. However, the extensive use of additive flame retardants can lead to a decline in the mechanical properties of RPUF and a lack of sustained flame retardant effect. Reactive flame retardants, on the other hand, can mitigate these negative impacts to some extent, and the synergistic effect of both can maximize their respective advantages.
[0003] Polyols, one of the raw materials for RPUF (Regenerative Polyurethane Flame Retardant), have historically relied heavily on petroleum resources. This has led to rising costs and resource depletion, as well as environmental pollution. Therefore, developing green, environmentally friendly, renewable, and effective bio-based polyols is an inevitable trend for future development. Castor oil is a naturally occurring polyhydroxy compound, but it has a low hydroxyl value, poor reactivity, and is prone to shrinkage. Chemical modification of its molecular structure, involving various active groups, can increase the hydroxyl value, enhance the crosslinking density of polyurethane, and expand its application areas. For example, CN117486931A provides a novel modified phosphorus-containing castor oil derivative that increases the hydroxyl content and functionality of castor oil, resulting in bio-based flame-retardant polyether polyols with good activity.
[0004] To address the two major problems of poor flame retardancy and non-renewable raw materials in RPUF, it is necessary to develop a composite flame-retardant rigid polyurethane foam that can replace part of the traditional polyether polyol with castor oil and further improve the flame retardant effect. Summary of the Invention
[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a castor oil-based phosphate ester flame-retardant polyol, its preparation method, and a composite flame-retardant rigid polyurethane foam prepared using the same. This invention provides a castor oil-based phosphate ester flame-retardant polyol, which can replace part of the traditional polyether polyol in the preparation of composite flame-retardant rigid polyurethane foam, significantly improving the flame-retardant and mechanical properties of the polyurethane rigid foam while reducing the use of petroleum resources.
[0006] This invention provides a castor oil-based phosphate ester flame-retardant polyol.
[0007] Specifically, a castor oil-based phosphate ester flame-retardant polyol has the structure shown in formula (1): Equation (1).
[0008] The present invention also provides a method for preparing the above-mentioned castor oil-based phosphate ester flame-retardant polyols.
[0009] Specifically, the preparation method of the above-mentioned castor oil-based phosphate ester flame-retardant polyol includes the following steps: S1. Castor oil and diethanolamine are mixed and subjected to an amidation reaction under the action of an alkaline catalyst to generate castor oil-based fatty amide. S2. The castor oil-based fatty amide prepared in step S1 is mixed with formic acid, and hydrogen peroxide is added dropwise under the action of an acidic catalyst to carry out an epoxidation reaction to generate epoxidized castor oil-based fatty amide. S3. The epoxidized castor oil-based fatty amide prepared in step S2 is mixed with diethyl phosphate and subjected to a ring-opening reaction under the action of an organophosphorus catalyst to generate castor oil-based phosphate flame-retardant polyol.
[0010] In some embodiments of the present invention, in step S1, the molar ratio of castor oil to diethanolamine is 1:(1-3).
[0011] In some embodiments of the present invention, in step S1, the alkaline catalyst includes at least one of sodium methoxide and potassium hydroxide; the amount of the alkaline catalyst is 0.05% to 0.3% of the total mass of the castor oil and the diethanolamine. Preferably, the amount of the alkaline catalyst is 0.1% to 0.2% of the total mass of the castor oil and the diethanolamine.
[0012] In some embodiments of the present invention, in step S1, the temperature of the amidation reaction is 110-130°C, and the time of the amidation reaction is 2-5 hours.
[0013] In some embodiments of the present invention, in step S2, the molar ratio of the castor oil-based fatty amide to the formic acid and the hydrogen peroxide is 1:(0.5-0.8):(1-3).
[0014] In some embodiments of the present invention, in step S2, the acidic catalyst includes at least one selected from phosphoric acid, p-toluenesulfonic acid, sulfuric acid, and cation exchange resin; the amount of the acidic catalyst is 1% to 5% of the mass of the castor oil-based fatty amide. Preferably, the amount of the acidic catalyst is 2% to 4% of the mass of the castor oil-based fatty amide.
[0015] In some embodiments of the present invention, in step S2, the temperature of the epoxidation reaction is 50-70°C, and the time of the epoxidation reaction is 5-8 hours.
[0016] In some embodiments of the present invention, in step S3, the molar ratio of the epoxidized castor oil-based fatty amide to the diethyl phosphate is 1:(1 to 1.2).
[0017] In some embodiments of the present invention, in step S3, the organophosphorus catalyst is at least one of triphenylphosphine and triphenyl phosphate; the amount of the organophosphorus catalyst is 0.5% to 3% of the mass of the epoxidized castor oil-based fatty amide.
[0018] In some embodiments of the present invention, in step S3, the temperature of the ring-opening reaction is 150-170°C, and the time of the ring-opening reaction is 3-6 hours.
[0019] The present invention also provides a composite flame-retardant rigid polyurethane foam.
[0020] Specifically, a composite flame-retardant rigid polyurethane foam comprises the following raw material components by weight: 15-55 parts of the above-mentioned castor oil-based phosphate ester flame-retardant polyols 45-85 parts of polyether polyol 90-130 parts of isocyanate 10-25 parts of additive flame retardant Catalyst 0.5-3 parts 15-45 parts of foaming agent; The additive flame retardant includes modified expanded graphite and phosphonate compounds, wherein the mass ratio of the modified expanded graphite to the phosphonate compounds is (1.5-4):1.
[0021] In some embodiments of the present invention, the modified expanded graphite is aluminate coupling agent modified expanded graphite. The preparation method of the modified expanded graphite is as follows: the aluminate coupling agent and expanded graphite are mixed at a mass ratio of (0.5-3):100, ground, and dispersed.
[0022] In some embodiments of the present invention, the aluminate coupling agent includes at least one of DL-411, SG-Al821, and LD-B.
[0023] In some embodiments of the present invention, the mass ratio of the modified expanded graphite to the phosphonate compound is (2-4):1, such as (2-3):1.
[0024] In some embodiments of the present invention, the phosphonate compound is dimethyl methylphosphonate (DMMP).
[0025] In some embodiments of the present invention, the polyether polyol is polyether 4110 (hydroxyl value = 400-460 mgKOH / g); the ratio of the castor oil-based phosphate flame retardant polyol to the polyether polyol is 1:(1-4).
[0026] In some embodiments of the present invention, the catalyst is a tin-based catalyst and / or an amine catalyst. The tin-based catalyst includes dibutyltin dilaurate or stannous octoate. The amine catalyst includes triethylenediamine or N,N-dimethylcyclohexylamine.
[0027] In some embodiments of the present invention, the isocyanate is polymethylene polyphenyl polyisocyanate (PAPI).
[0028] In some embodiments of the present invention, the foaming agent is one of HCFC-141b, HFC-365mfc or cyclopentane.
[0029] In some embodiments of the present invention, the composite flame-retardant rigid polyurethane foam comprises the following raw material components in parts by weight: 20-50 parts of the above-mentioned castor oil-based phosphate ester flame-retardant polyols 50-80 parts of polyether polyol 100-120 parts of isocyanate 12-20 parts of additive flame retardant 1-2 parts of catalyst 20-40 parts of foaming agent.
[0030] In some embodiments of the present invention, the raw material components of the composite flame-retardant rigid polyurethane foam further include a foam stabilizer and water. By weight, the foam stabilizer comprises 1 to 3 parts, and the water comprises 1 to 2 parts.
[0031] In some embodiments of the present invention, the foam stabilizer is one of AK8804, AK8812, and AK8814.
[0032] By weight, the composite flame-retardant rigid polyurethane foam comprises the following raw material components: 20-50 parts of the above-mentioned castor oil-based phosphate ester flame-retardant polyols 50-80 parts of polyether polyol 100-120 parts of isocyanate 12-20 parts of additive flame retardant 1-2 parts of catalyst 20-40 parts of foaming agent 1-3 parts foam stabilizer 1-2 parts water.
[0033] The present invention also provides a method for preparing composite flame-retardant rigid polyurethane foam.
[0034] Specifically, a method for preparing a composite flame-retardant rigid polyurethane foam includes the following steps: The above-mentioned castor oil-based phosphate flame-retardant polyols are mixed with polyether polyols to obtain a first mixture; an additive flame retardant, catalyst, foaming agent, foam stabilizer and water are added to the first mixture and stirred to obtain a second mixture; isocyanate is added to the second mixture, and after mixing, it is poured into a mold for foaming and curing to obtain rigid polyurethane foam.
[0035] In some embodiments of the present invention, the foaming and curing temperature is 65-80°C, and the foaming and curing time is 2.5-5 hours.
[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention utilizes reactive castor oil-based flame-retardant polyols, modified expanded graphite flame retardants, and phosphonate compounds (such as dimethyl methylphosphonate) to enhance the flame-retardant properties of rigid polyurethane foam through a synergistic flame-retardant effect. The limiting oxygen index (LOI) can reach 27%–29%, while also improving the mechanical properties of rigid polyurethane foam. Castor oil, one of the raw materials for castor oil-based phosphate flame-retardant polyols, is abundant and has the natural advantages of being renewable and environmentally friendly, which is conducive to the sustainable development of polyurethane materials. The castor oil-based phosphate flame-retardant polyols provided by this invention introduce flame-retardant elements N and P directly into the molecular chain structure of castor oil through structural modification. The chemical bonding within the structure extends the flame retardancy of the material, replacing part of the traditional polyether polyols. At the same time, it can reduce the use of additive flame-retardant fillers and improve the mechanical properties of rigid polyurethane foam. Furthermore, the combined use of modified expanded graphite and dimethyl methylphosphonate as additive flame retardants can achieve complementary effects by controlling their ratio, thereby maximizing the synergistic flame retardant benefits. In addition, the use of modified expanded graphite can significantly improve the storage stability of polyurethane materials.
[0037] (2) This invention provides a castor oil-based phosphate flame-retardant polyol. This reactive castor oil-based flame-retardant polyol replaces part of the traditional polyether polyol and works synergistically with two additive flame retardants, modified expanded graphite and dimethyl methylphosphonate, to prepare a composite flame-retardant rigid polyurethane foam, which can significantly improve the flame retardant performance, mechanical properties and storage stability of the rigid polyurethane foam. Detailed Implementation
[0038] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.
[0039] Unless otherwise specified, the raw materials, reagents or apparatus used in the following examples and comparative examples are available from conventional commercial sources or can be obtained by existing known methods.
[0040] Example 1 A castor oil-based phosphate ester flame-retardant polyol has the following structure: .
[0041] Its preparation method is as follows: S1. Under nitrogen protection, castor oil and the basic catalyst sodium methoxide were mixed in a four-necked flask. After the temperature was raised to 80°C, diethanolamine (the molar ratio of castor oil to diethanolamine was 1:1, and the basic catalyst sodium methoxide accounted for 0.1% of the total mass of the raw materials) was slowly added dropwise. After the addition was completed, the mixture was subjected to an amidation reaction at 110°C for 3 hours. The resulting product was dissolved in ethyl acetate and washed with saturated sodium chloride and sodium sulfate solutions. Then, the solvent was removed by rotary evaporation to obtain castor oil-based fatty amide.
[0042] S2. Epoxidation of castor oil-based fatty amide: Castor oil-based fatty amide, formic acid, and acidic catalyst phosphoric acid are mixed in a four-necked flask and stirred for 30 min. Hydrogen peroxide is then slowly added dropwise (the molar ratio of castor oil-based fatty amide, formic acid, and hydrogen peroxide is 1:0.5:2, and the acidic catalyst phosphoric acid accounts for 2% of the mass of castor oil-based fatty amide). After the addition is complete, the epoxidation reaction is carried out at 70 °C for 5.5 h. Similarly, the obtained product is dissolved in ethyl acetate, washed, and rotary evaporated to obtain epoxidized castor oil-based fatty amide.
[0043] S3. To introduce phosphate groups into the epoxidized castor oil-based fatty amide through ring-opening, the epoxidized castor oil-based fatty amide, diethyl phosphate, and triphenylphosphine catalyst (the molar ratio of epoxidized castor oil-based fatty amide to diethyl phosphate is 1:1, and the triphenylphosphine catalyst accounts for 1% of the mass of the epoxidized castor oil-based fatty amide) are mixed in a four-necked flammable ...
[0044] A composite flame-retardant rigid polyurethane foam based on castor oil has the following raw material composition as shown in Table 1.
[0045] Its preparation method includes the following steps: (1) Preparation of modified expanded graphite flame retardant: Aluminate coupling agent DL-411 and expanded graphite were ground and mixed and dispersed at high speed at a mass ratio of 1:100, and then dried at 100℃ for 1.5h for later use; (2) Preparation of rigid polyurethane foam: Castor oil-based phosphate flame retardant polyols are mixed with polyether polyols to obtain a first mixture; then, additive flame retardant, catalyst, foaming agent, foam stabilizer and water are added to the first mixture and stirred thoroughly to obtain a second mixture; finally, isocyanate is quickly added to the second mixture, and after mixing with a high-speed mixer, it is poured into a mold and foamed at 70°C for 4 hours to obtain rigid polyurethane foam.
[0046] Example 2 A castor oil-based phosphate ester flame-retardant polyol, with the same structure as in Example 1.
[0047] The preparation method of this castor oil-based phosphate ester flame-retardant polyol is as follows: S1. Under nitrogen protection, castor oil and potassium hydroxide (a basic catalyst) were mixed in a four-necked flask. After the temperature reached 80°C, diethanolamine (the molar ratio of castor oil to diethanolamine was 1:3, and potassium hydroxide accounted for 0.2% of the total mass of the raw materials) was slowly added dropwise. After the addition was complete, the mixture was subjected to an amidation reaction at 120°C for 3.5 hours. The resulting product was dissolved in ethyl acetate and washed with saturated sodium chloride and sodium sulfate solutions. The solvent was then removed by rotary evaporation to obtain a castor oil-based fatty amide.
[0048] S2. Castor oil-based fatty amide was epoxidized. In a four-necked flask, castor oil-based fatty amide, formic acid, and the acidic catalyst p-toluenesulfonic acid were mixed and stirred for 30 min. Then, hydrogen peroxide was slowly added dropwise (the molar ratio of castor oil-based fatty amide, formic acid, and hydrogen peroxide was 1:0.6:1, and the acidic catalyst p-toluenesulfonic acid accounted for 3% of the mass of the castor oil-based fatty amide). After the addition was complete, the epoxidation reaction was carried out at 60 °C for 6 h. Similarly, the obtained product was dissolved in ethyl acetate, washed, and rotary evaporated to obtain epoxidized castor oil-based fatty amide.
[0049] S3. Finally, the epoxidized castor oil-based fatty amide was ring-opened to introduce phosphate groups. The epoxidized castor oil-based fatty amide, diethyl phosphate, and triphenyl phosphate catalyst were mixed in a four-necked flask (the molar ratio of epoxidized castor oil-based fatty amide to diethyl phosphate was 1:1.1, and the triphenyl phosphate catalyst accounted for 2% of the mass of the epoxidized castor oil-based fatty amide). The ring-opening reaction was carried out at 150°C for 4.5 h to obtain the final desired castor oil-based phosphate flame-retardant polyol.
[0050] A composite flame-retardant rigid polyurethane foam based on castor oil has the following raw material composition as shown in Table 1.
[0051] Its preparation method includes the following steps: (1) Preparation of modified expanded graphite flame retardant: Aluminate coupling agent SG-Al821 and expanded graphite were ground and mixed and dispersed at high speed at a mass ratio of 1:100, and then dried at 100℃ for 1 hour before use. (2) Preparation of rigid polyurethane foam: Castor oil-based phosphate flame retardant polyols are mixed with polyether polyols to obtain a first mixture; then, additive flame retardant, catalyst, foaming agent, foam stabilizer and water are added to the first mixture and stirred thoroughly to obtain a second mixture; finally, isocyanate is quickly added to the second mixture, and after mixing with a high-speed mixer, it is poured into a mold and foamed at 75°C for 3 hours to obtain rigid polyurethane foam.
[0052] Example 3 A castor oil-based phosphate ester flame-retardant polyol, with the same structure as in Example 1.
[0053] The preparation method of this castor oil-based phosphate ester flame-retardant polyol is as follows: S1. Under nitrogen protection, castor oil and the basic catalyst sodium methoxide were mixed in a four-necked flask. After the temperature was raised to 80°C, diethanolamine (the molar ratio of castor oil to diethanolamine was 1:2, and the basic catalyst sodium methoxide accounted for 0.17% of the total mass of the raw materials) was slowly added dropwise. After the addition was complete, the mixture was amidated at 120°C for 3 hours. The resulting product was dissolved in ethyl acetate and washed with saturated sodium chloride and sodium sulfate solutions. Then, the solvent was removed by rotary evaporation to obtain castor oil-based fatty amide.
[0054] S2. Castor oil-based fatty amide was epoxidized. In a four-necked flask, castor oil-based fatty amide, formic acid, and the acidic catalyst phosphoric acid were mixed and stirred for 30 min. Then, hydrogen peroxide was slowly added dropwise (the molar ratio of castor oil-based fatty amide, formic acid, and hydrogen peroxide was 1:0.6:3, and the acidic catalyst phosphoric acid accounted for 3% of the mass of castor oil-based fatty amide). After the addition was complete, the epoxidation reaction was carried out at 60 °C for 6 h. Similarly, the obtained product was dissolved in ethyl acetate, washed, and rotary evaporated to obtain epoxidized castor oil-based fatty amide.
[0055] S3. Finally, the epoxidized castor oil-based fatty amide was ring-opened to introduce phosphate groups. The epoxidized castor oil-based fatty amide, diethyl phosphate, and triphenylphosphine catalyst were mixed in a four-necked flask (the molar ratio of epoxidized castor oil-based fatty amide to diethyl phosphate was 1:1, and the triphenylphosphine catalyst accounted for 3% of the mass of the epoxidized castor oil-based fatty amide). The ring-opening reaction was carried out at 160°C for 4 hours to obtain the final desired castor oil-based phosphate ester flame-retardant polyol.
[0056] A composite flame-retardant rigid polyurethane foam based on castor oil has the following raw material composition as shown in Table 1.
[0057] Its preparation method includes the following steps: (1) Preparation of modified expanded graphite flame retardant: Aluminate coupling agent DL-411 and expanded graphite were ground and mixed and dispersed at high speed at a mass ratio of 1:100, and then dried at 110℃ for 1 hour before use. (2) Preparation of rigid polyurethane foam: Castor oil-based phosphate flame retardant polyols are mixed with polyether polyols to obtain a first mixture; then, additive flame retardant, catalyst, foaming agent, foam stabilizer and water are added to the first mixture and stirred thoroughly to obtain a second mixture; finally, isocyanate is quickly added to the second mixture, and after mixing with a high-speed mixer, it is poured into a mold and foamed at 75°C for 4 hours to obtain rigid polyurethane foam.
[0058] Example 4 A castor oil-based phosphate ester flame-retardant polyol, with the same structure as in Example 1.
[0059] The preparation method of this castor oil-based phosphate ester flame-retardant polyol is as follows: S1. Under nitrogen protection, castor oil and the basic catalyst sodium methoxide were mixed in a four-necked flask. After the temperature was raised to 80°C, diethanolamine (the molar ratio of castor oil to diethanolamine was 1:3, and the basic catalyst sodium methoxide accounted for 0.2% of the total mass of the raw materials) was slowly added dropwise. After the addition was complete, the mixture was amidated at 130°C for 2.5 h. The resulting product was dissolved in ethyl acetate and washed with saturated sodium chloride and sodium sulfate solutions. Then, the solvent was removed by rotary evaporation to obtain castor oil-based fatty amide.
[0060] S2. Castor oil-based fatty amide was epoxidized. In a four-necked flask, castor oil-based fatty amide, formic acid, and sulfuric acid (an acidic catalyst) were mixed and stirred for 30 min. Then, hydrogen peroxide was slowly added dropwise (the molar ratio of castor oil-based fatty amide, formic acid, and hydrogen peroxide was 1:0.8:3, and the sulfuric acid catalyst accounted for 4% of the mass of the castor oil-based fatty amide). After the addition was complete, the epoxidation reaction was carried out at 50 °C for 6.5 h. Similarly, the resulting product was dissolved in ethyl acetate, washed, and rotary evaporated to obtain epoxidized castor oil-based fatty amide.
[0061] S3. To introduce phosphate groups into the epoxidized castor oil-based fatty amide through ring-opening, the epoxidized castor oil-based fatty amide, diethyl phosphate, and triphenylphosphine catalyst (the molar ratio of epoxidized castor oil-based fatty amide to diethyl phosphate is 1:1, and the triphenylphosphine catalyst accounts for 0.5% of the mass of the epoxidized castor oil-based fatty amide) are mixed in a four-necked flammable ...
[0062] A composite flame-retardant rigid polyurethane foam based on castor oil has the following raw material composition as shown in Table 1.
[0063] Its preparation method includes the following steps: (1) Preparation of modified expanded graphite flame retardant: The aluminate coupling agent LD-B and expanded graphite were ground and mixed and dispersed at high speed at a mass ratio of 1:100, and then dried at 120℃ for 0.5h for later use. (2) Preparation of rigid polyurethane foam: Castor oil-based phosphate flame retardant polyol and polyether polyol are mixed to obtain the first mixture; then add additive flame retardant, catalyst, foaming agent, foam stabilizer and water to the first mixture, stir and mix thoroughly to obtain the second mixture; finally, add isocyanate to the second mixture quickly, mix with a high-speed mixer and pour into a mold, and foam at 70°C for 3 hours to obtain rigid polyurethane foam.
[0064] Example 5 A castor oil-based phosphate ester flame-retardant polyol, with the same structure as in Example 1.
[0065] The preparation method of this castor oil-based phosphate ester flame-retardant polyol is as follows: S1. Under nitrogen protection, castor oil and potassium hydroxide (a basic catalyst) were mixed in a four-necked flask. After the temperature reached 80°C, diethanolamine (the molar ratio of castor oil to diethanolamine was 1:1, and potassium hydroxide accounted for 0.15% of the total mass of the raw materials) was slowly added dropwise. After the addition was complete, the mixture was amidated at 115°C for 3.5 hours. The resulting product was dissolved in ethyl acetate and washed with saturated sodium chloride and sodium sulfate solutions. The solvent was then removed by rotary evaporation to obtain a castor oil-based fatty amide.
[0066] S2. Castor oil-based fatty amide was epoxidized. In a four-necked flask, castor oil-based fatty amide, formic acid, and an acidic catalyst cation exchange resin were mixed and stirred for 30 min. Then, hydrogen peroxide was slowly added dropwise (the molar ratio of castor oil-based fatty amide, formic acid, and hydrogen peroxide was 1:0.5:1.5, and the acidic catalyst cation exchange resin accounted for 2% of the mass of castor oil-based fatty amide). After the addition was complete, the epoxidation reaction was carried out at 70 °C for 6 h. Similarly, the obtained product was dissolved in ethyl acetate, washed, and rotary evaporated to obtain epoxidized castor oil-based fatty amide.
[0067] S3. Finally, the epoxidized castor oil-based fatty amide was ring-opened to introduce phosphate groups. The epoxidized castor oil-based fatty amide, diethyl phosphate, and triphenylphosphine catalyst were mixed in a four-necked flask (the molar ratio of epoxidized castor oil-based fatty amide to diethyl phosphate was 1:1.2, and the triphenylphosphine catalyst accounted for 3% of the mass of the epoxidized castor oil-based fatty amide). The ring-opening reaction was carried out at 160℃ for 4 hours to obtain the final desired castor oil-based phosphate ester flame-retardant polyol.
[0068] A composite flame-retardant rigid polyurethane foam based on castor oil has the following raw material composition as shown in Table 1.
[0069] Its preparation method includes the following steps: (1) Preparation of modified expanded graphite flame retardant: Aluminate coupling agent DL-411 and expanded graphite were ground and mixed and dispersed at high speed at a mass ratio of 1:100, and then dried at 120℃ for 1 hour before use. (2) Preparation of rigid polyurethane foam: Castor oil-based phosphate flame retardant polyols are mixed with polyether polyols to obtain a first mixture; then, additive flame retardant, catalyst, foaming agent, foam stabilizer and water are added to the first mixture and stirred thoroughly to obtain a second mixture; finally, isocyanate is quickly added to the second mixture, and after mixing with a high-speed mixer, it is poured into a mold and foamed at 75°C for 3 hours to obtain rigid polyurethane foam.
[0070] The raw material composition of the composite flame-retardant polyurethane rigid foam in Examples 1 to 5 is shown in Table 1. All raw materials in Table 1 are expressed in parts by weight.
[0071] Table 1. Raw material components of composite flame-retardant polyurethane rigid foam materials in Examples 1-5
[0072] Comparative Example 1 The difference between this comparative example and Example 3 is that castor oil-based phosphate flame-retardant polyols are not used; only a single polyether 4110 polyol is used. The specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0073] Comparative Example 2 The difference between this comparative example and Example 3 is that no additional additive flame retardants (modified expanded graphite and DMMP) were used. The specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0074] Comparative Example 3 The difference between this comparative example and Example 3 is that the modified expanded graphite is replaced with an equal amount of unmodified expanded graphite, and the specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0075] Comparative Example 4 The difference between this comparative example and Example 3 is that only modified expanded graphite is added, and DMMP is not used. The specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0076] Comparative Example 5 The only difference between this comparative example and Example 3 is that the mass ratio of modified expanded graphite to DMMP is set to 1:1, that is, 10 parts of both modified expanded graphite and DMMP. The specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0077] Comparative Example 6 The only difference between this comparative example and Example 3 is that the mass ratio of modified expanded graphite to DMMP is set to 6:1, that is, 17.1 parts of modified expanded graphite and 2.9 parts of DMMP. The specific raw material composition for preparing rigid polyurethane foam is shown in Table 2.
[0078] The raw material composition of the composite flame-retardant polyurethane rigid foams in Comparative Examples 1 to 6 is shown in Table 2. All raw materials in Table 2 are expressed in parts by weight.
[0079] Table 2 shows the raw material components of the composite flame-retardant polyurethane rigid foam materials in Comparative Examples 1–6.
[0080] Product effectiveness test The polyurethane rigid foams prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to relevant performance tests such as limiting oxygen index (LOI), compressive strength, and storage stability.
[0081] The limiting oxygen index (%) was tested according to the test standard ASTM D-2863, and the compressive strength (kPa) was tested according to GB / T 8813-2008.
[0082] Storage stability: After storing the polyurethane rigid foams prepared in each example and comparative example in a dry and cool curing room (avoiding extreme harsh environments) for three months, take the polyurethane rigid foams from each group and apply adhesive, ensuring the same net content. Test the ease of application and whether clogging occurs. If the adhesive is easy to apply and no clogging occurs, the storage stability is good and is recorded as O; if the adhesive is difficult to apply and clogging occurs, the storage stability is poor and is recorded as X.
[0083] The test results are shown in Table 3.
[0084] Table 3 Performance Test Results
[0085] As shown in Table 3, the castor oil-based rigid polyurethane foams prepared in Examples 1-5 of this invention possess excellent flame retardant and mechanical properties. In these embodiments, specific castor oil-based phosphate ester flame-retardant polyols were selected, with modified expanded graphite as one of the additive flame retardants. The proportions of the castor oil-based phosphate ester flame-retardant polyols to polyether 4110, as well as the proportions of modified expanded graphite and phosphonate ester compounds in the additive flame retardants, were controlled to achieve a limiting oxygen index of up to 29.4% for the prepared castor oil-based composite flame-retardant rigid polyurethane foam, making it a flame-retardant material. Simultaneously, this material also maintains good compressive strength and storage stability.
[0086] Furthermore, comparing Example 3 with Comparative Example 1, it is evident that replacing part of the traditional polyether polyol with castor oil-based phosphate ester flame-retardant polyol improves both the flame retardant and mechanical properties of the resulting rigid polyurethane foam. Moreover, castor oil-based polyol is a readily available and environmentally friendly raw material, which is more conducive to sustainable development. Comparing Example 3 with Comparative Example 2, it is clear that the added flame retardant significantly improves the flame retardancy of rigid polyurethane foam. Comparing Example 3 with Comparative Example 3, it is evident that the addition of expanded graphite as a flame retardant has little impact on the flame retardant properties of rigid polyurethane foam, but the use of modified expanded graphite significantly improves its mechanical properties and storage stability. After three months of storage, it was found that the rigid polyurethane foam prepared with unmodified expanded graphite experienced nozzle clogging during application, demonstrating that modified expanded graphite can significantly improve the mechanical properties and storage stability of rigid polyurethane foam.
[0087] Comparing Example 3 with Comparative Examples 4, 5, and 6, it is evident that the combined use and proportional control of modified expanded graphite and phosphonate compounds in additive flame retardants are crucial for improving the flame retardant properties, mechanical properties, and storage stability of rigid polyurethane foam. Excessive addition of modified expanded graphite directly affects the application and sealing of rigid polyurethane foam; while excessive addition of DMMP causes shrinkage of the rigid polyurethane foam, significantly reducing its mechanical properties.
[0088] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A castor oil-based phosphate ester flame-retardant polyol, characterized in that, Its structure is shown in equation (1): Equation (1).
2. The method for preparing the castor oil-based phosphate ester flame-retardant polyol according to claim 1, characterized in that, Includes the following steps: S1. Castor oil and diethanolamine are mixed and subjected to an amidation reaction under the action of an alkaline catalyst to generate castor oil-based fatty amide. S2. The castor oil-based fatty amide prepared in step S1 is mixed with formic acid, and hydrogen peroxide is added dropwise under the action of an acidic catalyst to carry out an epoxidation reaction to generate epoxidized castor oil-based fatty amide. S3. The epoxidized castor oil-based fatty amide prepared in step S2 is mixed with diethyl phosphate and subjected to a ring-opening reaction under the action of an organophosphorus catalyst to generate castor oil-based phosphate flame-retardant polyol.
3. The preparation method according to claim 2, characterized in that, In step S1, the molar ratio of castor oil to diethanolamine is 1:(1-3); the amount of alkaline catalyst is 0.05% to 0.3% of the total mass of castor oil and diethanolamine; the temperature of the amidation reaction is 110-130°C; and the time of the amidation reaction is 2-5 hours.
4. The preparation method according to claim 2, characterized in that, In step S2, the molar ratio of the castor oil-based fatty amide to the formic acid and the hydrogen peroxide is 1:(0.5-0.8):(1-3); the acidic catalyst includes at least one of phosphoric acid, p-toluenesulfonic acid, sulfuric acid, and cation exchange resin; the amount of the acidic catalyst is 1%-5% of the mass of the castor oil-based fatty amide; the temperature of the epoxidation reaction is 50-70°C, and the time of the epoxidation reaction is 5-8 hours.
5. The preparation method according to claim 2, characterized in that, In step S3, the molar ratio of the epoxidized castor oil-based fatty amide to the diethyl phosphate is 1:(1-1.2); in step S3, the organophosphorus catalyst is at least one of triphenylphosphine and triphenyl phosphate; the amount of the organophosphorus catalyst is 0.5% to 3% of the mass of the epoxidized castor oil-based fatty amide; the ring-opening reaction temperature is 150-170°C, and the ring-opening reaction time is 3-6 hours.
6. A composite flame-retardant rigid polyurethane foam, characterized in that, By weight, it includes the following raw material components: 15-55 parts of the castor oil-based phosphate ester flame-retardant polyol according to claim 1 45-85 parts of polyether polyol 90-130 parts of isocyanate 10-25 parts of additive flame retardant Catalyst 0.5-3 parts 15-45 parts of foaming agent; The additive flame retardant includes modified expanded graphite and phosphonate compounds, wherein the mass ratio of the modified expanded graphite to the phosphonate compounds is (1.5-4):
1.
7. The composite flame-retardant rigid polyurethane foam according to claim 6, characterized in that, The modified expanded graphite is an aluminate coupling agent modified expanded graphite; the preparation method of the modified expanded graphite is as follows: the aluminate coupling agent and expanded graphite are mixed at a mass ratio of (0.5~3):100, ground and dispersed.
8. The composite flame-retardant rigid polyurethane foam according to claim 6 or 7, characterized in that, The mass ratio of the modified expanded graphite to the phosphonate compound is (2-4):1; the phosphonate compound is dimethyl methylphosphonate.
9. The composite flame-retardant rigid polyurethane foam according to claim 6 or 7, characterized in that, The catalyst is a tin-based catalyst and / or an amine-based catalyst; the tin-based catalyst includes dibutyltin dilaurate or stannous octoate; the amine-based catalyst includes triethylenediamine or N,N-dimethylcyclohexylamine.
10. The method for preparing the composite flame-retardant rigid polyurethane foam according to any one of claims 6 to 9, characterized in that, Includes the following steps: The castor oil-based phosphate flame-retardant polyol of claim 1 is mixed with a polyether polyol to obtain a first mixture; an additive flame retardant, a catalyst, a foaming agent, a foam stabilizer and water are added to the first mixture and stirred to obtain a second mixture; isocyanate is added to the second mixture, and after mixing, it is poured into a mold for foaming and curing to obtain rigid polyurethane foam.