A low-density polyurethane foam material, a method for preparing the same, and an application thereof

Abstract

The application belongs to the technical field of polyurethane materials, and particularly relates to a low-density polyurethane foam material and a preparation method and application thereof. The low-density polyurethane foam material comprises A component and B component with a mass ratio of 1: (0.4-0.6). The A component comprises the following raw materials in parts by weight: polyether polyol 60-80 parts, polyester polyol 5-15 parts, flame retardant 5-10 parts, antibacterial agent 1-2 parts, foaming agent 3-8 parts, catalyst 0.3-0.8 parts, surfactant 0.5-1.2 parts, and antioxidant 0.1-0.3 parts. The B component is isocyanate. The application introduces the antibacterial agent and the flame retardant which have the dual effects of 'function' and'structure', so that the obtained polyurethane foam has excellent mechanical strength, antibacterial and flame-retardant properties while maintaining low density, and realizes the integration of 'function-structure'.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, specifically relating to a low-density polyurethane foam material, its preparation method, and its application. Background Technology

[0002] Polyurethane foam materials, especially flexible polyurethane foam, are widely used in home furnishings (such as mattresses, sofas, and pillows), vehicle interiors (such as car seats and headrests), packaging cushioning materials, and sporting goods due to their excellent lightweight, high resilience, cushioning performance, and processability, becoming an indispensable polymer material in modern life. However, its inherent flammability and susceptibility to microbial growth severely limit its application in high-end fields.

[0003] To improve performance, existing technologies mainly employ physical blending to add small-molecule flame retardants (such as halogenated and phosphorus-based agents) and antibacterial agents (such as quaternary ammonium salts). This method presents a fundamental contradiction: firstly, achieving effective functionality requires high addition levels, which significantly degrades the foam's flexibility, resilience, and key mechanical properties (such as tear strength); secondly, small-molecule additives are prone to migration and precipitation, leading to short-lasting functionality and potentially causing secondary pollution. Particularly noteworthy is that when both flame retardant and antibacterial functions are required simultaneously, simple blending exacerbates performance degradation and fails to resolve the inherent conflict between functionality and mechanical properties.

[0004] For example, CN101585901A achieves good mechanical properties and certain bulk antibacterial properties in polyurethane foam by using a complex combination of polyether polyols and a high foaming density (>100kg / m³). However, this method cannot integrate multiple functions while obtaining low-density foam, and the antibacterial effect is limited. CN114773827A forms a composite polyol with strong flame retardant properties by reacting sea buckthorn seed oil, tung oil, formaldehyde, 3-methoxypropionic acid, hydroxylating agent, and tricyanamide to impart flame retardant function to flexible polyurethane foam, but it is still difficult to achieve a balance between high-efficiency flame retardancy, long-lasting antibacterial effect, and excellent mechanical properties in a low-density foam system.

[0005] Therefore, developing a novel material that can integrate multiple functions into the molecular structure of foam without sacrificing its intrinsic properties has become a technical challenge that urgently needs to be overcome in this field. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the primary objective of this invention is to provide a low-density polyurethane foam material, its preparation method, and its application.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A low-density polyurethane foam material comprises component A and component B in a mass ratio of 1:(0.4-0.6); component A comprises the following raw materials in parts by weight: 60-80 parts of polyether polyol, 5-15 parts of polyester polyol, 5-10 parts of flame retardant, 1-2 parts of antibacterial agent, 3-8 parts of foaming agent, 0.3-0.8 parts of catalyst, 0.5-1.2 parts of surfactant, and 0.1-0.3 parts of antioxidant; component B is isocyanate;

[0009] The structural formula of the antibacterial agent is as follows:

[0010] .

[0011] Preferably, the antibacterial agent is prepared by the following process:

[0012] (1) Add o-vanillin to ethanol, then add an aqueous solution of aminothiourea to react and obtain intermediate 1;

[0013] The structural formula of intermediate 1 is as follows:

[0014] ;

[0015] (2) Disperse intermediate 1 in water, then add ferric chloride solution to react, filter after the reaction is complete, add citric acid and sodium citrate to the filtrate, and treat with ammonia to obtain intermediate 2;

[0016] The structural formula of intermediate 2 is as follows:

[0017] ;

[0018] (3) Add intermediate 2 to acetic acid, and then add indole-3-carboxaldehyde to react and obtain intermediate 3;

[0019] The structural formula of intermediate 3 is as follows:

[0020] ;

[0021] (4) Under the action of potassium carbonate, intermediate 3 is reacted with 4-hydroxybenzenesulfonyl chloride to obtain the antibacterial agent.

[0022] Preferably, in step (1), the molar ratio of o-vanillin and aminothiourea is 1:(1-1.2), the reaction temperature is 50-60 ℃, and the time is 4-6 h; in step (2), the molar ratio of intermediate 1, ferric chloride, citric acid and sodium citrate is 1:(3-4):(2.2-2.4):(1-1.2), the reaction temperature is 80-90 ℃, and the time is 100-120 min.

[0023] Preferably, in step (3), the molar ratio of intermediate 2 to indole-3-carboxaldehyde is 1:(1-1.5), and the reaction time is 6-8 h; in step (4), the molar ratio of intermediate 3, potassium carbonate and 4-hydroxybenzenesulfonyl chloride is 1:(1-1.2):(1-1.2), and the reaction is carried out in acetone and refluxed for 4-5 h.

[0024] Preferably, the flame retardant is prepared by the following process:

[0025] (a) Vanillin and 3-aminopropyl-1,2-diol were reacted in ethanol to give a reaction mixture; then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to the reaction mixture to continue the reaction, giving compound 1; the structural formula of compound 1 is as follows:

[0026] ;

[0027] (b) Reaction of cyanuric chloride and 4-aminophenylboronic acid in acetone yields compound 2; the structural formula of compound 2 is as follows:

[0028] ;

[0029] (c) Compound 1 and Compound 2 are reacted in N,N-dimethylformamide to obtain the flame retardant; the structural formula of the flame retardant is as follows:

[0030] .

[0031] Preferably, in step (a), the molar ratio of o-vanillin, 3-aminoprop-1,2-diol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(1.02-1.1):(1-1.1); the reaction temperature is 70-80 °C and the reaction time is 8-10 h; the reaction continues for 6-8 h.

[0032] Preferably, the molar ratio of cyanuric chloride and 4-aminophenylboronic acid in step (b) is 1:(3.2-3.5); and the molar ratio of compound 1 and compound 2 in step (c) is (3-3.2):1.

[0033] Preferably, the polyether polyol has a functionality of 3 and a hydroxyl value of 32-36 mg KOH / g; the polyester polyol has a functionality of 2.5-3 and a hydroxyl value of 55-65 mg KOH / g; the surfactant is silicone oil DC-193; the foaming agent is composed of water and cyclopentane in a mass ratio of (1-3):(2-5); and the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:1. More preferably, the polyether polyol is polyether 330N; the polymethylene polyphenyl isocyanate (PAPI) has an NCO content of 30-32% and is purchased from Bayer AG, Germany; and the isocyanate TDI is purchased from Wanhua Chemical.

[0034] A method for preparing the above-mentioned low-density polyurethane foam material includes the following steps: mixing polyether polyol, polyester polyol, antibacterial agent, flame retardant, foaming agent, catalyst, surfactant and antioxidant evenly to obtain component A; mixing component A and component B evenly, foaming, curing and aging to obtain the final product.

[0035] Preferably, the curing temperature is 60-70 ℃ and the time is 2-3 h; the ripening time is 24 h.

[0036] An application of the aforementioned low-density polyurethane foam material in the preparation of household goods, vehicle interiors, packaging cushioning materials, and sporting goods.

[0037] The present invention has the following advantages over the prior art:

[0038] 1. This invention introduces antibacterial and flame retardant agents that have both "functional" and "structural" functions, so that the resulting polyurethane foam maintains low density while synergistically possessing excellent mechanical strength, antibacterial and flame retardant properties, thus achieving "functional-structural" integration.

[0039] 2. In the antibacterial agent of this invention, the 1,3,4-thiadiazole ring and indole ring are connected by Schiff base bonds, forming an extended conjugated hydrophobic plane. This plane can efficiently insert into and disrupt the microbial cell membrane, while interfering with intracellular enzyme metabolism. Simultaneously, the terminal sulfonyl group enhances the interaction with the cell membrane, thereby achieving highly efficient antibacterial activity. More importantly, this antibacterial agent is rich in rigid aromatic rings and polar groups (C=N, -O-, -SO2-), which not only firmly anchor it to the polyurethane matrix through strong interactions, solving the problem of easy migration of small molecule antibacterial agents, but also serve as rigid physical crosslinking points, effectively improving the mechanical strength of the foam. Furthermore, the nitrogen, sulfur, and other heteroatoms it contains can produce trace amounts of gas-phase flame retardant effect during combustion, synergistically enhancing the flame retardant effect of the material with the main active ingredient of the flame retardant.

[0040] 3. The flame retardant of this invention uses a triazine ring as its core, with three rigid side arms containing DOPO and catechol structures connected by borate ester bonds. Upon heating, the components exert a multi-element synergistic effect: DOPO provides gas-phase free radical capture and catalysis for condensed-phase char formation; the triazine ring decomposes to produce non-flammable gases; and the borate ester bonds promote the formation of a dense and robust "BPNC" composite expanded char layer, thereby endowing the material with extremely high flame retardancy. Furthermore, the three-dimensional rigid structure of this macromolecule effectively avoids the migration and plasticizing side effects of small-molecule flame retardants. Its large side arms act as dendritic reinforcing agents in the matrix, not only without compromising mechanical properties but also synergistically improving the mechanical strength of the material with the antibacterial agent, achieving a unity of flame retardancy and toughness. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products obtained through commercial channels.

[0042] The polyether polyols in the following examples and comparative examples are polyether 330N polyols with a functionality of 3 and a hydroxyl value of 32-36 mg KOH / g; the polyester polyols have a functionality of 2.5-3 and a hydroxyl value of 55-65 mg KOH / g; the surfactant is silicone oil DC-193; the foaming agent is composed of water and cyclopentane in a mass ratio of (1-3):(2-5); the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:1; the NCO content of polymethylene polyphenyl isocyanate (PAPI) is 30-32%, purchased from Bayer AG, Germany, and the isocyanate TDI is purchased from Wanhua Chemical.

[0043] Example 1

[0044] Example 1 provides an antibacterial agent, the preparation process of which is as follows:

[0045]

[0046] (1) Dissolve 0.2 mol of o-vanillin in 300 mL of ethanol and 0.22 mol of aminothiourea in 300 mL of deionized water. Then slowly mix the two solutions and stir continuously at 55 °C for 5 h. After cooling the reaction solution, separate it immediately, filter and dry it to obtain intermediate 1 with a yield of 97.8%. 1 H NMR (C9H) 11 N3O2S, 400 MHz, d 6-DMSO) δ 13.75(s, 1H), 11.30(s, 1H), 8.28 (s, 1H), 7.32 (d, 1H), 7.00 (d, 1H), 6.89(t, 1H),3.89 (s, 3H), 3.25 (s, 2H); HRMS (ESI + ): [M+H] + The calculation yields 226.06, and the value is found to be 226.06.

[0047] (2) Intermediate 1 (0.05 mol) was suspended in 300 mL of deionized water, and 300 mL of FeCl3 (0.18 mol) aqueous solution was slowly added. The mixture was heated to 85 °C and maintained for 110 min. The solution was filtered, and then citric acid (0.11 mol) and sodium citrate (0.05 mol) were added. The mixture was then treated with 10% ammonia water until pH=7.3. The product was filtered, dried, and recrystallized with ethanol to obtain intermediate 2 with a yield of 86.8%. 1 H NMR (C9H9N3O2S, 400 MHz, d 6 -DMSO) δ 10.30(s, 1H),8.28 (s, 1H), 7.30 (d, 1H), 7.22(s, 1H), 7.01 (t, 1H), 6.89(d, 1H), 3.89 (s,3H); HRMS (ESI + ): [M+H] + The calculation yields 224.04, and the value is found to be 224.04.

[0048] (3) Dissolve intermediate 2 (0.01 mol) in 30 mL of acetic acid, add 30 mL of ethanol solution of indole-3-carboxaldehyde (CAS:487-89-8, 0.012 mol), and reflux for 7 h; after cooling, pour the reaction mixture into crushed ice, let it stand overnight to precipitate, filter, wash thoroughly with petroleum ether, dry, and recrystallize with ethanol to obtain intermediate 3, with a yield of 94.5%; 1 HNMR (C 18 H 14 N4O2S, 400 MHz, d 6-DMSO) δ 11.29(s, 1H), 10.30 (s, 1H), 9.32(s, 1H),8.41(d, 1H), 7.63(s, 1H), 7.42(d, 1H), 7.30(d, 1H), 7.19(t, 1H), 7.08(t, 1H),7.01 (t, 1H), 6.89(d, 1H), 3.89 (s, 3H); HRMS (ESI + ): [M+H] + The result is 351.08, and the value is 351.09.

[0049] (4) Intermediate 3 (10 mmol) and anhydrous potassium carbonate (11 mmol) were added to 100 mL of dry acetone, and then 4-hydroxybenzenesulfonyl chloride (11 mmol) was added. The mixture was refluxed for 4 h. After cooling the reaction mixture, the product was repeatedly washed with petroleum ether (50 °C) to obtain the antibacterial agent with a yield of 88.0%. 1 H NMR (C 24 H 18 N4O5S2, 400 MHz, d 6 -DMSO) δ 11.96(s, 1H), 10.30 (s, 1H), 9.48(s, 1H), 8.21(d, 1H), 7.63(s, 2H), 7.55(s, 1H),7.48(d, 1H), 7.30(d, 1H), 7.19-7.16(m, 4H), 7.01 (t, 1H), 6.89(d, 1H), 3.89(s, 3H); HRMS (ESI + ): [M+H] + The calculation yields 507.07, and the result is 507.08.

[0050] Example 2

[0051] Example 2 provides an antibacterial agent, the preparation process of which is as follows:

[0052] (1) Dissolve 0.2 mol of vanillin in 300 mL of ethanol and 0.2 mol of aminothiourea in 300 mL of deionized water. Then slowly mix the two solutions and stir continuously at 50 °C for 6 h. After cooling the reaction solution, separate it immediately, filter and dry it to obtain intermediate 1 with a yield of 97.0%.

[0053] (2) Intermediate 1 (0.05 mol) was suspended in 300 mL of deionized water, and 300 mL of FeCl3 (0.15 mol) aqueous solution was slowly added. The mixture was heated to 80 °C and maintained for 120 min. The solution was filtered, and then citric acid (0.11 mol) and sodium citrate (0.06 mol) were added. The mixture was then treated with 10% ammonia water until pH=7.2. The product was filtered, dried, and recrystallized with ethanol to obtain intermediate 2 with a yield of 86.1%.

[0054] (3) Dissolve intermediate 2 (0.01 mol) in 30 mL of acetic acid, add 30 mL of ethanol solution of indole-3-carboxaldehyde (CAS:487-89-8, 0.01 mol), and reflux for 6 h; after cooling, pour the reaction mixture into crushed ice, let it stand overnight to precipitate, filter, wash thoroughly with petroleum ether, dry and recrystallize with ethanol to obtain intermediate 3, with a yield of 93.9%.

[0055] (4) Add intermediate 3 (10 mmol) and anhydrous potassium carbonate (10 mmol) to 100 mL of dry acetone, then add 4-hydroxybenzenesulfonyl chloride (10 mmol), and reflux for 4 h. After cooling the reaction mixture, wash the product repeatedly with petroleum ether (40 °C) to obtain the antibacterial agent with a yield of 87.6%.

[0056] Example 3

[0057] Example 3 provides an antibacterial agent, the preparation process of which is as follows:

[0058] (1) Dissolve 0.2 mol of vanillin in 300 mL of ethanol and 0.24 mol of aminothiourea in 300 mL of deionized water. Then slowly mix the two solutions and stir continuously at 60 °C for 4 h. After cooling the reaction solution, separate it immediately, filter and dry it to obtain intermediate 1 with a yield of 98.4%.

[0059] (2) Intermediate 1 (0.05 mol) was suspended in 300 mL of deionized water, and 300 mL of FeCl3 (0.20 mol) aqueous solution was slowly added. The mixture was heated to 90 °C and maintained for 100 min. The solution was filtered, and then citric acid (0.12 mol) and sodium citrate (0.05 mol) were added. The mixture was then treated with 10% ammonia water until pH=7.5. The product was filtered, dried, and recrystallized with ethanol to obtain intermediate 2 with a yield of 87.2%.

[0060] (3) Dissolve intermediate 2 (0.01 mol) in 30 mL of acetic acid, add 30 mL of ethanol solution of indole-3-carboxaldehyde (CAS:487-89-8, 0.015 mol), and reflux for 8 h; after cooling, pour the reaction mixture into crushed ice, let it stand overnight to precipitate, filter, wash thoroughly with petroleum ether, dry and recrystallize with ethanol to obtain intermediate 3, with a yield of 95.0%.

[0061] (4) Add intermediate 3 (10 mmol) and anhydrous potassium carbonate (12 mmol) to 100 mL of dry acetone, then add 4-hydroxybenzenesulfonyl chloride (12 mmol), and reflux for 5 h. After cooling the reaction mixture, the product was repeatedly washed with petroleum ether (60 °C) to obtain the antibacterial agent with a yield of 88.4%.

[0062] Example 4

[0063] Example 4 provides a flame retardant, the preparation process of which is as follows:

[0064]

[0065] (a) Vanillin (0.50 mol) and ethanol (300 mL) were added to a three-necked flask and heated until completely dissolved. Then, 100 mL of ethanol solution containing 3-aminopropyl-1,2-diol (CAS: 616-30-8, 0.52 mol) was added dropwise to the flask, and the reaction was carried out at 75 °C for 9 h to obtain a reaction mixture. Then, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO, 0.52 mol) was added to the reaction mixture, and the reaction was continued for 7 h. Subsequently, the solvent was removed by rotary evaporation to obtain a yellow powder. Finally, the yellow powder was washed twice with ethyl acetate and dried in a vacuum oven at 80 °C for 12 h to obtain compound 1, with a yield of 91.4%. 1 H NMR (C 23 H 24 NO6P, 400 MHz, d 6 -DMSO) δ 9.58(s, 1H), 8.02(d, 1H),7.75(d, 1H), 7.50-7.30(m, 6H), 6.81-6.74(m, 3H), 6.38(s, 1H), 5.38(s, 1H),4.94(s, 1H), 3.92(d, 1H), 3.89 (s, 3H), 3.59-3.55(m, 3H), 2.68(t, 2H); HRMS(ESI + ): [M+H] +The result is 442.13, and the value is 442.14.

[0066] (b) Cyanurium chloride (10 mmol) and 4-aminophenylboronic acid (33 mmol) were dissolved in 100 mL of acetone and stirred at 2 °C for 1.5 h. Then, 10 mL of 4% sodium hydroxide solution was added dropwise while stirring rapidly, and the reaction was continued for 2.5 h. After the reaction was completed, the mixture was poured into crushed ice and neutralized with 2 M hydrochloric acid under continuous stirring until precipitation was complete. The mixture was filtered, washed with ice water, dried, and recrystallized in acetone to give compound 2, with a yield of 90.7%. 1 H NMR (C 21 H 21 B3N6O6, 400 MHz, d 6 -DMSO) δ 8.95(s, 3H), 7.71 (d, 6H), 7.19(d, 6H), 4.25 (s, 6H); HRMS (ESI + ):[M+H] + The calculation yields 487.18, and the value is found to be 487.18.

[0067] (c) Compound 1 (31 mmol) was added to 150 mL of DMF and stirred at 25°C for 12 min. Then, a DMF solution of compound 2 (10 mmol, 50 mL) was added and the reaction was continued for 26 h. The solution became turbid. The mixture was filtered, and the collected precipitate was washed with DMF and dried at 80°C for 12 h to obtain the flame retardant with a yield of 94.9%. 1 H NMR (C 90 H 81 B3N9O 18 P3, 400 MHz d 6 -DMSO) δ 9.58(s, 3H), 8.95(s, 3H), 8.02(d, 3H), 7.75-7.71(m, 9H), 7.50-7.30(m,18H), 7.19 (d, 6H), 6.81-6.74(m, 9H), 6.38(s, 3H), 4.18-4.15(m, 3H), 3.96-3.93(m, 6H), 3.89 (s, 9H), 3.64-3.58(m, 3H), 2.68(t,6H); HRMS (ESI + ): [M+H] + The calculation yields 1702.52, and the value is found to be 1702.52.

[0068] Example 5

[0069] Example 5 provides a flame retardant, the preparation process of which is as follows:

[0070] (a) Vanillin (0.50 mol) and ethanol (300 mL) were added to a three-necked flask and heated until completely dissolved. Then, 100 mL of ethanol solution containing 3-aminopropyl-1,2-diol (0.51 mol) was added dropwise to the flask, and the reaction was carried out at 70 °C for 10 h to obtain a reaction mixture. Then, DOPO (0.50 mol) was added to the reaction mixture, and the reaction was continued for 6 h. Subsequently, the solvent was removed by rotary evaporation to obtain a yellow powder. Finally, the yellow powder was washed twice with ethyl acetate and dried in a vacuum oven at 80 °C for 12 h to obtain compound 1, with a yield of 90.8%.

[0071] (b) Cyanurium chloride (10 mmol) and 4-aminophenylboronic acid (32 mmol) were dissolved in 100 mL of acetone and stirred at 0 °C for 1 h. Then, 10 mL of 4% sodium hydroxide solution was added dropwise while stirring rapidly, and the reaction was continued for 3 h. After the reaction was completed, the mixture was poured into crushed ice and neutralized with 2 M hydrochloric acid under continuous stirring until the precipitation was complete. The mixture was filtered, washed with ice water, dried, and recrystallized in acetone to give compound 2 with a yield of 90.3%.

[0072] (c) Compound 1 (30 mmol) was added to 150 mL of DMF and stirred at 20 °C for 15 min. Then, a DMF solution of compound 2 (10 mmol, 50 mL) was added and the reaction was continued at 20 °C for 30 h. The solution became turbid. The mixture was filtered, and the collected precipitate was washed with DMF and dried at 80 °C for 12 h to obtain the flame retardant with a yield of 94.3%.

[0073] Example 6

[0074] Example 6 provides a flame retardant, the preparation process of which is as follows:

[0075] (a) Vanillin (0.50 mol) and ethanol (300 mL) were added to a three-necked flask and heated until completely dissolved. Then, 100 mL of ethanol solution containing 3-aminopropyl-1,2-diol (0.55 mol) was added dropwise to the flask, and the reaction was carried out at 80 °C for 8 h to obtain a reaction mixture. Then, DOPO (0.55 mol) was added to the reaction mixture, and the reaction was continued for 6 h. Subsequently, the solvent was removed by rotary evaporation to obtain a yellow powder. Finally, the yellow powder was washed twice with ethyl acetate and dried in a vacuum oven at 80 °C for 12 h to obtain compound 1, with a yield of 92.0%.

[0076] (b) Cyanurium chloride (10 mmol) and 4-aminophenylboronic acid (35 mmol) were dissolved in 100 mL of acetone and stirred at 5 °C for 1 h. Then, 10 mL of 4% sodium hydroxide solution was added dropwise while stirring rapidly, and the reaction was continued for 2 h. After the reaction was completed, the mixture was poured into crushed ice and neutralized with 2 M hydrochloric acid under continuous stirring until the precipitation was complete. The mixture was filtered, washed with ice water, dried, and recrystallized in acetone to give compound 2 with a yield of 91.2%.

[0077] (c) Compound 1 (32 mmol) was added to 150 mL of DMF and stirred at 25°C for 15 min. Then, a DMF solution of compound 2 (10 mmol, 50 mL) was added and the reaction was continued at 25°C for 24 h. The solution became turbid. The mixture was filtered, and the collected precipitate was washed with DMF and dried at 80°C for 12 h to obtain the flame retardant with a yield of 95.6%.

[0078] Example 7

[0079] Example 7 provides a low-density polyurethane foam material, comprising component A and component B in a mass ratio of 1:0.5;

[0080] Component A above comprises the following raw materials in parts by weight: 80 parts polyether polyol, 15 parts polyester polyol, 10 parts flame retardant, 2 parts antibacterial agent, 8 parts foaming agent, 0.8 parts catalyst, 1.2 parts silicone oil DC-193, and 0.3 parts antioxidant 1010; wherein, the foaming agent is composed of water and cyclopentane in a mass ratio of 1:1; the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:1.

[0081] The above component B includes the following raw materials in parts by weight: 92 parts of polymethylene polyphenyl isocyanate (PAPI) and 8 parts of toluene diisocyanate (TDI).

[0082] Example 7 also provides a method for preparing the above-mentioned low-density polyurethane foam material, comprising the following steps:

[0083] S1. Place the polyether polyol and polyester polyol in an 85 ℃ vacuum drying oven for 2.5 h to dehydrate, and control the water content to below 0.05%; grind the synthesized antibacterial agent and flame retardant to a particle size of more than 500 mesh, and set aside for later use;

[0084] S2. In a room temperature stirred tank, first add the dehydrated polyether polyol and polyester polyol, and stir at 600 r / min for 5 min. Then add the antibacterial agent and flame retardant in sequence, and increase the speed to 1100 r / min and stir for 12 min. Finally, add the foaming agent, catalyst, silicone oil DC-193 and antioxidant 1010, and keep stirring at 800 r / min for 5 min to obtain component A.

[0085] S3. Add PAPI and TDI to a sealed container in proportion, and stir at 300 r / min for 4 min at 45 ℃ to obtain component B;

[0086] S4. Weigh out components A and B according to the ratio, pour them into a high-speed mixer, stir at 2200 r / min for 10 s until the system is milky white and there are no obvious bubbles. Then quickly pour the mixture into a mold preheated to 45 ℃, and let it foam naturally until the system no longer expands (about 4 min). Then put it into a 65 ℃ oven to cure for 2.5 h. Remove the cured foam from the mold and let it mature at room temperature for 24 h to obtain low-density polyurethane foam material.

[0087] Example 8

[0088] Example 8 provides a low-density polyurethane foam material, comprising component A and component B in a mass ratio of 1:0.4;

[0089] Component A above comprises the following raw materials in parts by weight: 60 parts polyether polyol, 5 parts polyester polyol, 5 parts flame retardant, 1 part antibacterial agent, 3 parts foaming agent, 0.3 parts catalyst, 0.5 parts silicone oil DC-193, and 0.1 parts antioxidant 1010; wherein, the foaming agent is composed of water and cyclopentane in a mass ratio of 3:5; the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:1.

[0090] The above component B includes the following raw materials in parts by weight: 90 parts of polymethylene polyphenyl isocyanate (PAPI) and 5 parts of toluene diisocyanate (TDI).

[0091] Example 8 also provides a method for preparing the above-mentioned low-density polyurethane foam material, comprising the following steps:

[0092] S1. Place the polyether polyol and polyester polyol in an 80℃ vacuum drying oven for 3 hours to dehydrate, and control the water content to below 0.05%; grind the synthesized antibacterial agent and flame retardant to a particle size of 500 mesh or higher, and set aside for later use.

[0093] S2. In a room temperature stirred tank, first add the dehydrated polyether polyol and polyester polyol, and stir at 500 r / min for 5 min. Then add the antibacterial agent and flame retardant in sequence, and increase the speed to 1000 r / min and stir for 15 min. Finally, add the foaming agent, catalyst, silicone oil DC-193 and antioxidant 1010, and keep stirring at 800 r / min for 5 min to obtain component A.

[0094] S3. Add PAPI and TDI to a sealed container in proportion, and stir at 300 r / min for 5 min at 40 ℃ to obtain component B;

[0095] S4. Weigh out components A and B according to the ratio, pour them into a high-speed mixer, stir at 2000 r / min for 12 s until the system is milky white and there are no obvious bubbles. Then quickly pour the mixture into a mold preheated to 40 ℃, and let it foam naturally until the system no longer expands (about 5 min). Then put it into a 60 ℃ oven to cure for 3 h. Remove the cured foam from the mold and let it mature at room temperature for 24 h to obtain low-density polyurethane foam material.

[0096] Example 9

[0097] Example 9 provides a low-density polyurethane foam material, comprising component A and component B in a mass ratio of 1:0.6;

[0098] Component A above comprises the following raw materials in parts by weight: 70 parts polyether polyol, 10 parts polyester polyol, 8 parts flame retardant, 1.5 parts antibacterial agent, 5 parts foaming agent, 0.5 parts catalyst, 0.8 parts silicone oil DC-193, and 0.2 parts antioxidant 1010; wherein, the foaming agent is composed of water and cyclopentane in a mass ratio of 1:2; the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:1.

[0099] The above-mentioned component B includes the following raw materials in parts by weight: 95 parts of polymethylene polyphenyl isocyanate (PAPI) and 10 parts of toluene diisocyanate (TDI).

[0100] Example 9 also provides a method for preparing the above-mentioned low-density polyurethane foam material, comprising the following steps:

[0101] S1. Place the polyether polyol and polyester polyol in a vacuum drying oven at 90 ℃ for 2 h to dehydrate, and control the water content to below 0.05%; grind the synthesized antibacterial agent and flame retardant to a particle size of 500 mesh or higher, and set aside for later use.

[0102] S2. In a room temperature stirred tank, first add the dehydrated polyether polyol and polyester polyol, and stir at 800 r / min for 5 min. Then add the antibacterial agent and flame retardant in sequence, and increase the speed to 1200 r / min and stir for 10 min. Finally, add the foaming agent, catalyst, silicone oil DC-193 and antioxidant 1010, and keep stirring at 800 r / min for 5 min to obtain component A.

[0103] S3. Add PAPI and TDI to a sealed container in proportion, and stir at 300 r / min for 3 min at 50 ℃ to obtain component B;

[0104] S4. Weigh out components A and B according to the ratio, pour them into a high-speed mixer, and stir at 2500 r / min for 8 s until the system is milky white and there are no obvious bubbles. Then quickly pour the mixture into a mold preheated to 50℃, and let it foam naturally until the system no longer expands (about 3 min). Then put it into a 70℃ oven to cure for 2 h. Remove the cured foam from the mold and let it mature at room temperature for 24 h to obtain low-density polyurethane foam material.

[0105] Comparative Example 1

[0106] The content of Comparative Example 1 is basically the same as that of Example 7, except that the antibacterial agent is omitted.

[0107] Comparative Example 2

[0108] Comparative Example 2 is basically the same as Example 7, except that the flame retardant is replaced with the conventional additive flame retardant TCPP (tris(2-chloropropyl) phosphate).

[0109] Experimental Example 1

[0110] The following performance tests were performed on the polyurethane foam materials obtained in Examples 7-9 and Comparative Examples 1-2.

[0111] Foam density: Tested according to GB / T 6343-2009 "Determination of apparent density of foamed plastics and rubber";

[0112] Tensile strength and elongation at break: Tested according to GB / T 6344-2008 "Determination of tensile strength and elongation at break of flexible foam polymer materials", with a tensile rate of 500 mm / min.

[0113] Tear strength: Tested according to GB / T 10808-2006 "Determination of tear strength of porous elastic polymer materials", with a sample size of 25 mm × 25 mm × 85 mm and a tearing rate of 50 mm / min;

[0114] Antibacterial properties: Tested according to QB / T 2591-2003 "Test methods and antibacterial effects of antibacterial plastics";

[0115] Flame retardant performance: Tested according to GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test";

[0116] The test results are shown in Table 1.

[0117] Table 1 Performance test results of various polyurethane foam materials

[0118]

[0119] As shown in Table 1, the polyurethane foam material prepared by this invention has low density, excellent mechanical properties, and excellent flame retardant and antibacterial properties.

[0120] Compared to Example 7, Comparative Example 1 omits the antibacterial agent described in this invention, resulting in a significant decrease in its antibacterial rate and tear strength, as well as a reduction in tensile strength. This indicates that the antibacterial agent of this invention, in addition to imparting antibacterial function to the material, also plays a physical reinforcing role. Its rigid aromatic heterocyclic structure can effectively prevent crack propagation and improve the mechanical strength of the material. Furthermore, the oxygen index of Comparative Example 1 is slightly lower than that of Example 7, suggesting that the N and S heteroatoms contained in the antibacterial agent molecule may produce a trace amount of synergistic flame-retardant effect with the flame retardant during combustion, further enhancing the flame-retardant effect.

[0121] Compared to Example 7, Comparative Example 2 replaced the flame retardant described in this invention with the conventional additive flame retardant TCPP, and its flame retardant performance and mechanical properties both decreased significantly. This indicates that the flame retardant efficiency of the macromolecular PNB flame retardant designed in this invention is higher than that of the conventional small-molecule flame retardant TCPP. Moreover, its large three-dimensional rigid structure not only does not impair mechanical properties, but can also serve as a reinforcing point to work with antibacterial agents to improve the strength of foam.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A low-density polyurethane foam material, characterized in that, The product comprises component A and component B in a mass ratio of 1:(0.4-0.6); component A comprises the following raw materials in parts by weight: 60-80 parts of polyether polyol, 5-15 parts of polyester polyol, 5-10 parts of flame retardant, 1-2 parts of antibacterial agent, 3-8 parts of foaming agent, 0.3-0.8 parts of catalyst, 0.5-1.2 parts of surfactant, and 0.1-0.3 parts of antioxidant; component B is isocyanate. The structural formula of the antibacterial agent is as follows: ； The structural formula of the flame retardant is as follows: 。 2. The low-density polyurethane foam material according to claim 1, characterized in that, The antibacterial agent is prepared by the following process: (1) Add o-vanillin to ethanol, then add an aqueous solution of aminothiourea to react and obtain intermediate 1; The structural formula of intermediate 1 is as follows: ； (2) Disperse intermediate 1 in water, then add ferric chloride solution to react, filter after the reaction is complete, add citric acid and sodium citrate to the filtrate, and treat with ammonia to obtain intermediate 2; The structural formula of intermediate 2 is as follows: ； (3) Add intermediate 2 to acetic acid, and then add indole-3-carboxaldehyde to react and obtain intermediate 3; The structural formula of intermediate 3 is as follows: ； (4) Under the action of potassium carbonate, intermediate 3 is reacted with 4-hydroxybenzenesulfonyl chloride to obtain the antibacterial agent.

3. The low-density polyurethane foam material according to claim 2, characterized in that, In step (1), the molar ratio of o-vanillin and aminothiourea is 1:(1-1.2), the reaction temperature is 50-60 ℃, and the time is 4-6 h; in step (2), the molar ratio of intermediate 1, ferric chloride, citric acid and sodium citrate is 1:(3-4):(2.2-2.4):(1-1.2), the reaction temperature is 80-90 ℃, and the time is 100-120 min.

4. The low-density polyurethane foam material according to claim 2, characterized in that, In step (3), the molar ratio of intermediate 2 and indole-3-carboxaldehyde is 1:(1-1.5), and the reaction time is 6-8 h; in step (4), the molar ratio of intermediate 3, potassium carbonate and 4-hydroxybenzenesulfonyl chloride is 1:(1-1.2):(1-1.2), and the reaction is carried out in acetone and refluxed for 4-5 h.

5. The low-density polyurethane foam material according to claim 1, characterized in that, The flame retardant is prepared by the following process: (a) Vanillin and 3-aminopropyl-1,2-diol were reacted in ethanol to give a reaction mixture; then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to the reaction mixture to continue the reaction, giving compound 1; the structural formula of compound 1 is as follows: ； (b) Reaction of cyanuric chloride and 4-aminophenylboronic acid in acetone yields compound 2; the structural formula of compound 2 is as follows: ； (c) Reacting compound 1 and compound 2 in N,N-dimethylformamide to obtain the flame retardant.

6. The low-density polyurethane foam material according to claim 5, characterized in that, In step (a), the molar ratio of o-vanillin, 3-aminoprop-1,2-diol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(1.02-1.1):(1-1.1); the reaction temperature is 70-80 °C, and the reaction time is 8-10 h; the reaction continues for 6-8 h.

7. The low-density polyurethane foam material according to claim 5, characterized in that, The molar ratio of cyanuric chloride and 4-aminophenylboronic acid in step (b) is 1:(3.2-3.5); the molar ratio of compound 1 and compound 2 in step (c) is (3-3.2):

1.

8. The low-density polyurethane foam material according to claim 1, characterized in that, The polyether polyol has a functionality of 3 and a hydroxyl value of 32-36 mg KOH / g; the polyester polyol has a functionality of 2.5-3 and a hydroxyl value of 55-65 mg KOH / g; the surfactant is silicone oil DC-193; the foaming agent is composed of water and cyclopentane in a mass ratio of (1-3):(2-5); the catalyst is composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 2:

1.

9. A method for preparing the low-density polyurethane foam material according to any one of claims 1-8, characterized in that, Includes the following steps: Mix polyether polyol, polyester polyol, antibacterial agent, flame retardant, foaming agent, catalyst, surfactant and antioxidant evenly to obtain component A; mix component A and component B evenly, foam, cure and mature to obtain the final product.

10. An application of the low-density polyurethane foam material according to any one of claims 1-8, characterized in that, Applications in the preparation of household goods, vehicle interiors, packaging cushioning materials, and sporting goods.

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