High-elastic flame-retardant foaming material for automobile and preparation method of high-elastic flame-retardant foaming material

Abstract

The invention relates to the technical field of foam materials, and discloses a high-elastic flame-retardant foam material for automobiles and a preparation method thereof.The foam material comprises, by weight, 100 parts of polyol, 2.2-3.5 parts of a foaming agent, 24-28 parts of an isocyanate compound, 20-40 parts of modified expandable graphite and the like; active imino groups are introduced into the modified expansible graphite to react with an isocyanate compound, so that the binding force between the expansible graphite and polyurethane is improved, and the influence of the expansible graphite on the mechanical property of the polyurethane foam material is reduced, so that higher compression strength and tensile strength are maintained, the strength is high, and the elasticity is excellent. The expandable graphite contains a large number of DOPO phosphorus-containing flame-retardant structures, plays a synergistic flame-retardant role, improves the limit oxygen index of the foaming material, can replace a traditional sponge material, and has good practical application in the aspects of new-energy automobile seat cushions, mattresses and the like.

Description

Technical Field

[0001] This invention relates to the field of foam materials technology, specifically to a high-elasticity flame-retardant foam material for automobiles and its preparation method. Background Technology

[0002] Compared to traditional sponge materials, ETPU polyurethane foam has better resilience, mechanical strength, and abrasion resistance, making it a viable alternative to sponge in cushions, mattresses, insulation materials, and sealing materials. However, ETPU foam has poor flame retardancy, is easily ignited, and produces a large amount of smoke, posing a significant safety hazard and limiting its practical application in areas such as new energy vehicles.

[0003] Expandable graphite is inexpensive, readily available, non-toxic, and environmentally friendly. Upon heating, it undergoes a dramatic volume expansion, forming a dense graphite carbon layer that provides smoke suppression and flame retardancy. It is a highly efficient halogen-free flame retardant with significant applications in materials such as polyurethane, polypropylene, and polyethylene. Patents CN103030965B and CN103012729B disclose the use of expandable graphite, DOPO-modified linseed oil, and tung oil to improve the flame retardant properties of polyurethane elastomers. However, expandable graphite has poor compatibility with polyurethane; adding excessive amounts can severely affect the mechanical properties of polyurethane and its foamed materials. Summary of the Invention

[0004] (I) Technical problem solved: The present invention provides a high-elasticity flame-retardant foam material for automobiles and its preparation method, which solves the problem of poor flame retardancy of polyurethane foam materials.

[0005] (II) Technical solution: A high-elasticity flame-retardant foam material, comprising 100 parts by weight of polyol, 1.3-2 parts by weight of catalyst, 2.2-3.5 parts by weight of foaming agent, 1.2-2 parts by weight of surfactant, 2.3-2.9 parts by weight of chain extender, 24-28 parts by weight of isocyanate compound, and 20-40 parts by weight of modified expandable graphite.

[0006] The preparation method of high-elasticity flame-retardant foam material is as follows: (1) Terephthalaldehyde and N,N-dimethylethylenediamine were added to ethanol to carry out the reaction, and then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to continue the reaction. After cooling, the mixture was filtered, the product was washed with ethanol, and dried to obtain the DOPO intermediate; the reaction formula is: .

[0007] (2) Add DOPO intermediate and 1-bromoalkane to acetonitrile, react, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize in an aqueous ethanol solution to obtain a cationic flame retardant modifier. The reaction formula is: .

[0008] (3) Add expandable graphite to an ethanol aqueous solution, stir to disperse, add cationic flame retardant modifier, stir to modify, filter, wash with ethanol aqueous solution, and dry to obtain modified expandable graphite.

[0009] (4) Mix the polyol, catalyst, foaming agent, surfactant and chain extender to obtain component A; mix the isocyanate compound and modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming and curing to obtain a high-elasticity flame-retardant foam material.

[0010] Furthermore, in (1), the ratio of terephthalaldehyde, N,N-dimethylethylenediamine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1 mol: (2-2.1) mol: (2-2.2) mol.

[0011] Furthermore, in (1), the reaction temperature is 75-80℃ and the reaction time is 6-8h; the reaction time continues for 12-18h.

[0012] Furthermore, in (2), the ratio of DOPO intermediate to 1-bromoalkane is 1 mol: (2-2.4) mol; the structural formula of the 1-bromoalkane is Br-C n H 2n+1 n is 2-6.

[0013] Furthermore, the reaction temperature in (2) is 80-85℃, and the reaction time is 18-24h.

[0014] Furthermore, in (3), the volume fraction of the ethanol aqueous solution is 70-90%.

[0015] Furthermore, in (3), the ratio of expandable graphite to cationic flame retardant modifier is 100g: (0.03-0.08)mol.

[0016] Furthermore, in (3), the temperature during stirring modification is 60-75℃ and the time is 1-4h.

[0017] Furthermore, the catalyst in (4) includes stannous octoate and triethylenediamine.

[0018] Furthermore, in (4), the foaming agent is water.

[0019] Furthermore, in (4), the surfactant is silicone oil.

[0020] Furthermore, the chain extenders in (4) include 1,4-butanediol and diethanolamine.

[0021] Furthermore, in (4), the isocyanate compound is polyphenyl polymethylene polyisocyanate.

[0022] Furthermore, (4) the aging temperature is 20-60℃ and the aging time is 6-168h.

[0023] Furthermore, highly elastic flame-retardant foam materials are used in automotive seat cushions, mattresses, and other applications.

[0024] (III) Beneficial technical effects: This invention utilizes the quaternary ammonium salt cations of cationic flame retardant modifiers to form cation-π bond interactions with the surface of expandable graphite, thereby achieving surface modification and alteration of expandable graphite. Then, it is polymerized and foamed with polyols, isocyanate compounds, catalysts, foaming agents, etc., to obtain a high-elasticity flame retardant foam material. The modified expandable graphite introduces active imino groups, which react with isocyanate compounds, thereby linking polyurethane molecules to the surface of expandable graphite, improving the bonding force between expandable graphite and polyurethane, improving their compatibility, and reducing the influence of expandable graphite on the mechanical properties of polyurethane foam material, thus maintaining high compressive strength and tensile strength, high strength, and excellent elasticity.

[0025] The modified expandable graphite of this invention contains a large amount of DOPO phosphorus-containing flame-retardant structure, which has the flame-retardant effect of free radical quenching in the gas phase and charring in the condensed phase. It works synergistically with expandable graphite to retard flames, significantly improves the limiting oxygen index of ETPU polyurethane foam material, and has excellent flame-retardant performance. It can replace traditional sponge materials and has good practical applications in new energy vehicle seat cushions and mattresses. Detailed Implementation

[0026] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0027] Example 1: (1) Add 0.1 mol of terephthalaldehyde and 0.21 mol of N,N-dimethylethylenediamine to 600 mL of ethanol, heat to 75 °C, stir and reflux for 8 h, then add 0.2 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 18 h, cool and filter, wash the product with ethanol, dry, and obtain DOPO intermediate.

[0028] (2) Add 0.1 mol of DOPO intermediate and 0.2 mol of 1-bromoethane to 700 mL of acetonitrile, heat to 85 °C, stir and reflux for 18 h, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize in an 80% ethanol aqueous solution to obtain a cationic flame retardant modifier.

[0029] (3) Add 30g of expandable graphite to 5L of 80% ethanol aqueous solution, stir and disperse, add 90mmol of cationic flame retardant modifier, heat to 70℃, stir, condense and reflux for 1h, filter, wash with ethanol aqueous solution, dry, and obtain modified expandable graphite.

[0030] (4) Mix 100g of polyol (model polyether polyol EP3600, Jinan Hongwang Chemical, the same below), 0.4g of stannous octoate, 1.5g of triethylenediamine, 2.7g of foaming agent water, 1.7g of silicone oil (model silicone oil 8110, Shandong Mingsheng Chemical), 1.6g of 1,4-butanediol and 1g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 20g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 20℃ for 7 days to obtain a high-elasticity flame-retardant foam material.

[0031] Example 2: (1) Add 0.2 mol of terephthalaldehyde and 0.4 mol of N,N-dimethylethylenediamine to 1.3 L of ethanol, heat to 75 °C, stir and reflux for 8 h, then add 0.48 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 12 h, cool and filter, wash the product with ethanol, dry, and obtain DOPO intermediate.

[0032] (2) Add 0.2 mol of DOPO intermediate and 0.4 mol of 1-bromobutane to 1.5 L of acetonitrile, heat to 85 °C, stir and reflux for 18 h, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize in an 80% ethanol aqueous solution to obtain a cationic flame retardant modifier.

[0033] (3) Add 30g of expandable graphite to 6L of 90% ethanol aqueous solution, stir and disperse, add 160mmol of cationic flame retardant modifier, heat to 60℃, stir, condense and reflux for 4h, filter, wash with ethanol aqueous solution, dry, and obtain modified expandable graphite.

[0034] (4) Mix 100g of polyol, 0.5g of stannous octoate, 1.5g of triethylenediamine, 2.2g of foaming agent water, 2g of silicone oil, 1.6g of 1,4-butanediol and 0.7g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 30g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 60℃ for 6h to obtain a high-elasticity flame-retardant foam material.

[0035] Example 3: (1) Add 0.2 mol of terephthalaldehyde and 0.4 mol of N,N-dimethylethylenediamine to 1.4 L of ethanol, heat to 80 °C, stir and reflux for 6 h, then add 0.44 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 12 h, cool and filter, wash the product with ethanol, dry, and obtain DOPO intermediate.

[0036] (2) Add 0.3 mol of DOPO intermediate and 0.72 mol of 1-bromopropane to 2.2 L of acetonitrile, heat to 80 °C, stir and reflux for 24 h, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize in an 80% ethanol aqueous solution to obtain a cationic flame retardant modifier.

[0037] (3) Add 30g of expandable graphite to 8L of 70% ethanol aqueous solution, stir and disperse, add 240mmol of cationic flame retardant modifier, heat to 75℃, stir, condense and reflux for 3h, filter, wash with ethanol aqueous solution, dry, and obtain modified expandable graphite.

[0038] (4) Mix 100g of polyol, 0.4g of stannous octoate, 0.9g of triethylenediamine, 3.5g of foaming agent water, 1.7g of silicone oil, 1.8g of 1,4-butanediol and 1.1g of diethanolamine to obtain component A; mix 27g of polyphenyl polymethylene polyisocyanate and 40g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 40°C for 3 days to obtain a high-elasticity flame-retardant foam material.

[0039] Comparative Example 1: (1) Mix 100g of polyol, 0.4g of stannous octoate, 1.5g of triethylenediamine, 2.7g of foaming agent water, 1.7g of silicone oil, 1.6g of 1,4-butanediol and 1g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 20g of expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 20°C for 7 days to obtain foamed material.

[0040] Comparative Example 2: (1) Add 30g of expandable graphite to 5L of 80% ethanol aqueous solution, stir and disperse, add 90mmol of cetyltrimethylammonium bromide, heat to 70℃, stir, reflux and modify for 1h, filter, wash with ethanol aqueous solution, and dry to obtain modified expandable graphite.

[0041] (2) Mix 100g of polyol, 0.4g of stannous octoate, 1.5g of triethylenediamine, 2.7g of foaming agent water, 1.7g of silicone oil, 1.6g of 1,4-butanediol and 1g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 20g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 20°C for 7 days to obtain foamed material.

[0042] Comparative Example 3: (1) Add 30g of expandable graphite to 5L of 80% ethanol aqueous solution, stir and disperse, add 90mmol of DOPO intermediate (prepared according to the method of Example 1), heat to 70℃, stir, condense and reflux for 1h to modify, filter, wash with ethanol aqueous solution, dry, and obtain modified expandable graphite.

[0043] (2) Mix 100g of polyol, 0.4g of stannous octoate, 1.5g of triethylenediamine, 2.7g of foaming agent water, 1.7g of silicone oil, 1.6g of 1,4-butanediol and 1g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 20g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 20°C for 7 days to obtain foamed material.

[0044] Comparative Example 4: (1) Add 0.1 mol of terephthalaldehyde and 0.21 mol of N,N-dimethylethylenediamine to 600 mL of ethanol, heat to 75 °C, stir and reflux for 8 h, filter after cooling, wash the product with petroleum ether, recrystallize the product in ethanol to obtain a Schiff base intermediate; the structural formula is .

[0045] (2) Add 0.1 mol of Schiff base intermediate and 0.2 mol of 1-bromoethane to 700 mL of acetonitrile, heat to 85 °C, stir and reflux for 18 h, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize in an 80% ethanol aqueous solution to obtain a cationic modifier with the following structural formula: .

[0046] (3) Add 30g of expandable graphite to 5L of 80% ethanol aqueous solution, stir and disperse, add 90mmol of cationic modifier, heat to 70℃, stir, condense and reflux for 1h, filter, wash with ethanol aqueous solution, and dry to obtain modified expandable graphite.

[0047] (4) Mix 100g of polyol, 0.4g of stannous octoate, 1.5g of triethylenediamine, 2.7g of foaming agent water, 1.7g of silicone oil, 1.6g of 1,4-butanediol and 1g of diethanolamine to obtain component A; mix 28g of polyphenyl polymethylene polyisocyanate and 20g of modified expandable graphite to obtain component B; add component B to component A, stir quickly, and then pour into a mold for free foaming. Cure at 20°C for 7 days to obtain foamed material.

[0048] The oxygen index of the foamed material was tested according to GB / T 2406.1-2008. The compressive properties were tested according to GB / T 8813-2020. The tensile properties were tested according to GB / T 9641-1988.

[0049] Table 1 Performance of Foamed Materials Compared with Comparative Example 1, the ETPU polyurethane foam materials of Examples 1-3 have higher limiting oxygen index, compressive strength, and tensile strength, and better flame retardancy and mechanical properties. This is mainly because the quaternary ammonium salt cations contained in the cationic flame retardant modifier form cation-π bonds with the surface of expandable graphite, thereby modifying the surface of expandable graphite. The introduced active imino groups react with isocyanate compounds, thereby linking polyurethane molecules to the surface of expandable graphite, improving the bonding force between expandable graphite and polyurethane, improving their compatibility, and reducing the influence of expandable graphite on the mechanical properties of polyurethane foam materials. This maintains high compressive strength and tensile strength. Furthermore, the modified expandable graphite contains a large number of DOPO phosphorus-containing flame retardant structures, which have the effects of free radical quenching flame retardancy in the gas phase and charring flame retardancy in the condensed phase. These structures work synergistically with expandable graphite to significantly improve the flame retardant performance of ETPU polyurethane foam materials and increase the limiting oxygen index.

[0050] Comparative Example 2's hexadecyltrimethylammonium bromide-modified expandable graphite does not contain active imino groups or DOPO phosphorus-containing flame-retardant structures, and its limiting oxygen index, compressive strength, and tensile strength are lower than those of Example 1.

[0051] The DOPO intermediate in Comparative Example 3 does not contain quaternary ammonium salt cations, making it difficult to modify the surface of expandable graphite. After washing, most of the DOPO intermediates were eluted from the expandable graphite matrix, and the limiting oxygen index, compressive strength, and tensile strength of the ETPU polyurethane foam were lower than those in Example 1.

[0052] The cationic modifier-modified expandable graphite in Comparative Example 4 does not contain active imino groups or DOPO phosphorus-containing flame-retardant structures. The limiting oxygen index, compressive strength, and tensile strength of the ETPU polyurethane foam material are lower than those in Example 1.

[0053] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A highly elastic flame-retardant foam material, characterized in that, The foaming material comprises 100 parts by weight of polyol, 1.3-2 parts by weight of catalyst, 2.2-3.5 parts by weight of foaming agent, 1.2-2 parts by weight of surfactant, 2.3-2.9 parts by weight of chain extender, 24-28 parts by weight of isocyanate compound, and 20-40 parts by weight of modified expandable graphite. The method for preparing the modified expandable graphite is as follows: expandable graphite is added to an ethanol aqueous solution, stirred and dispersed, a cationic flame retardant modifier is added, stirred and modified, filtered, washed, and dried to obtain the modified expandable graphite. The structural formula of the cationic flame retardant modifier is: n is 2-6.

2. The high-elasticity flame-retardant foam material according to claim 1, characterized in that, The catalyst includes stannous octoate and triethylenediamine; the foaming agent is water; the surfactant is silicone oil; the chain extender includes 1,4-butanediol and diethanolamine; and the isocyanate compound is polyphenyl polymethylene polyisocyanate.

3. The high-elasticity flame-retardant foam material according to claim 1, characterized in that, The volume fraction of the ethanol-water solution is 70-90%.

4. The high-elasticity flame-retardant foam material according to claim 1, characterized in that, The ratio of expandable graphite to cationic flame retardant modifier is 100g:(0.03-0.08)mol.

5. The high-elasticity flame-retardant foam material according to claim 1, characterized in that, The temperature during the stirring modification is 60-75℃, and the time is 1-4h.

6. The high-elasticity flame-retardant foam material according to claim 1, characterized in that, The preparation method of the cationic flame retardant modifier is as follows: (1) Add terephthalaldehyde and N,N-dimethylethylenediamine to ethanol, heat to 75-80℃, stir and reflux for 6-8h, then add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue the reaction for 12-18h, cool and filter, wash the product, dry to obtain DOPO intermediate; (2) Add DOPO intermediate and 1-bromoalkane to acetonitrile, heat to 80-85℃, stir and reflux for 18-24h, distill under reduced pressure, wash the product, and then recrystallize to obtain cationic flame retardant modifier.

7. The high-elasticity flame-retardant foam material according to claim 6, characterized in that, The ratio of terephthalaldehyde, N,N-dimethylethylenediamine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in (1) is 1 mol: (2-2.1) mol: (2-2.2) mol.

8. The high-elasticity flame-retardant foam material according to claim 6, characterized in that, In step (2), the ratio of DOPO intermediate to 1-bromoalkane is 1 mol: (2-2.4) mol; the structural formula of 1-bromoalkane is Br-C n H 2n+1 n is 2-6.

9. A method for preparing a highly elastic flame-retardant foamed material as described in any one of claims 1-7, characterized in that, The preparation method is as follows: polyol, catalyst, foaming agent, surfactant and chain extender are stirred together to obtain component A; isocyanate compound and modified expandable graphite are stirred and mixed to obtain component B; component B is added to component A, stirred rapidly, and then poured into a mold for free foaming, and then cured at 20-60℃ for 6-168h to obtain high elastic flame retardant foam material.

10. The application of a highly elastic flame-retardant foam material obtained by the preparation method as described in claim 9 in automotive seat cushions and mattresses.

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