Halogen-free flame-retardant polyurethane foam composition and use thereof

Abstract

The application discloses a halogen-free flame-retardant polyurethane foaming composition, and raw material compositions include, in parts by weight, flame-retardant polycarbonate diol 30-70 parts; polyether polyol 30-70 parts; diisocyanate 45-65 parts; small molecule polyol 1-5 parts; viscosity reducer 2-10 parts; processing aid 1-5 parts; foaming aid 1-15 parts. The preparation of the flame-retardant polycarbonate diol includes: adding a catalyst, an epoxide compound and a polyhydroxyalkyl phosphate into a high-pressure reactor, introducing CO2 into the high-pressure reactor, and obtaining the flame-retardant polycarbonate diol after polymerization. The halogen-free flame-retardant polyurethane foaming composition disclosed by the application can be foamed at room temperature, the prepared halogen-free flame-retardant foaming polyurethane has excellent flame retardancy, high foaming rate, uniform cells, softness and fine cells, and has high flame retardancy and excellent mechanical properties, and can meet the needs of actual application or the field of high-performance polyurethane.

Description

Technical Field

[0001] This invention belongs to the technical field of polyurethane, specifically relating to a halogen-free flame-retardant polyurethane foam composition and a method for preparing halogen-free flame-retardant polyurethane foam. Background Technology

[0002] Polyurethane, as a high-performance polymer material, is widely used in construction, automotive, and electronics industries. Polyurethane foam, with its excellent thermal insulation properties, is commonly used in the construction industry. Polyurethane elastomers, with their high strength and wear resistance, are widely used in tire and sealant manufacturing, improving vehicle safety and ride comfort. Secondly, due to its excellent insulation properties, polyurethane materials are used as key components such as electrical insulating paints and wire and cable protective sheaths, ensuring the stable operation of electronic equipment. Polyether polyols and polyester polyols are the two core raw materials for polyurethane material production. Polyether polyols are known for their flexibility, providing excellent elasticity and softness to polyurethane products, especially suitable for applications requiring good resilience and low-temperature flexibility, such as cushions and mattresses. However, their excessive softness sometimes limits their application in areas requiring higher strength or hardness. In contrast, polyester polyols give polyurethane greater hardness and better mechanical properties, resulting in products made from polyester-based polyurethane, such as tires and rigid foams, exhibiting excellent wear resistance and load-bearing capacity. However, polyester-based polyurethane materials have excessive hardness and relatively poor water resistance. At the same time, neither of them has flame-retardant properties and they are even flammable.

[0003] The flammability of polyurethane materials brings fire risks, as they burn rapidly and release toxic gases, posing a threat to human safety and the environment. Improving flame retardant properties not only enhances the safety of polyurethane materials but also promotes their widespread application in various fields, meeting the market demand for high-performance materials. With the increasingly widespread application of flame-retardant polyurethane materials, improving their flame retardant performance has become crucial. Adding flame retardants can effectively reduce their combustion rate and heat release, thus improving their flame retardant properties. However, this method usually requires the addition of a large amount of flame retardant. For example, Chinese patent document CN104861144A discloses a flame-retardant rigid polyurethane foam composed of the following components in parts by weight: 80-100 parts polyether polyol, 2-4 parts blowing agent, 10-30 parts crosslinking agent, 1-3 parts tertiary amine catalyst, 20-40 parts compounded flame retardant, and an isocyanate index of 1.0-2.5. This technical solution achieves the flame retardant effect of rigid polyurethane foam by adding 20-40 parts of a compound flame retardant composed of nitrogen-phosphorus intumescent flame retardant and expanded vermiculite. However, the addition of a large amount of flame retardant will reduce the tensile strength, elongation at break and other mechanical properties of polyurethane, and will also cause the foam to become less fluid during the foaming process, thus affecting the uniformity of foaming and the molding quality.

[0004] Polyurethane foam materials prepared from polycarbonate polyols possess thermal insulation, sound absorption, noise reduction, and corrosion resistance properties comparable to other conventional polyester-based polyurethane foam materials, and exhibit superior mechanical properties and hydrolysis resistance. Furthermore, carbon dioxide-based polyols themselves contain a certain mass fraction of CO2 (existing in a carbonate structure), thus possessing some flame retardancy and showing promise for the preparation of flame-retardant polyurethanes. Although carbon dioxide-based polyol products have entered the market and are used in coatings and adhesives, their high viscosity in polyurethane foam materials leads to difficulties in the foaming process. This limits their use in specific applications, such as cold chain logistics, building materials, and coal mining sealing materials, where high flame retardancy and mechanical properties are required. Summary of the Invention

[0005] To address the aforementioned issues, this invention discloses a halogen-free flame-retardant polyurethane foam composition that can be foamed at room temperature. The resulting halogen-free flame-retardant polyurethane foam exhibits excellent flame retardancy, high foaming rate, uniform cell structure, and is soft and dense. Furthermore, it combines high flame retardancy with excellent mechanical properties, meeting the needs of practical applications or the field of high-performance polyurethane.

[0006] The specific technical solution is as follows:

[0007] A halogen-free flame-retardant polyurethane foam composition, comprising, by weight, the following raw materials:

[0008]

[0009] The preparation of the flame-retardant polycarbonate diol includes:

[0010] A catalyst, an epoxy compound, and a polyhydroxyalkyl phosphate ester are added to a high-pressure reactor, and CO2 is introduced into the high-pressure reactor. After polymerization, flame-retardant polycarbonate diol is prepared.

[0011] The viscosity reducer is selected from one or more of (1-hydroxyethyl)phosphonate dimethyl ester, hydroxymethylphosphonate diethyl ester, and 2-hydroxyethylphosphonate dimethyl ester.

[0012] This invention discloses a halogen-free flame-retardant polyurethane foam composition. By employing a special phosphorus-containing chain transfer agent, a phosphate ester structure is introduced into the polycarbonate diol backbone, resulting in an in-situ prepared polycarbonate diol with excellent flame-retardant properties. Furthermore, it can synergistically enhance the flame-retardant effect with nitrogen in diisocyanates. This invention also utilizes a special viscosity reducer, which significantly lowers the viscosity of the flame-retardant polycarbonate diol with only a small amount added. This improves the operability of the composition during application, allowing for mixing at room temperature. Adjustments to the composition formulation result in a high foaming rate, uniform and fine-celled polyurethane foam, exhibiting both high flame retardancy and excellent mechanical properties.

[0013] The inventors hypothesized that the viscosity reducer used in this invention could effectively reduce the intermolecular forces of flame-retardant polycarbonate diols, thus reducing viscosity, similar to a plasticizer, but with a particularly significant effect on reducing the viscosity of polycarbonate diol systems. However, experiments revealed that at room temperature, if conventional plasticizers such as dioctyl phthalate, dibutyl phthalate, dioctyl phthalate, and dipropylene glycol dibenzoate are used, the system viscosity is reduced to half to one-third of that before the addition of plasticizers. When a moderate amount of the viscosity reducer of this invention is used, the system viscosity can be reduced to one-tenth or even lower.

[0014] In this invention, during the preparation of flame-retardant polycarbonate diol:

[0015] The epoxy compound is selected from propylene oxide and / or butane oxide;

[0016] The catalyst is selected from zinc-cobalt bimetallic cyanide catalysts or supported zinc-cobalt bimetallic cyanide catalysts; the mass percentage of the catalyst is 0.01 to 0.50 wt% based on the total mass of the epoxide compound;

[0017] The polyhydroxyalkyl phosphate is selected from phosphate molecules containing two or more hydroxyl groups, specifically from one or more of N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, dihydroxyethylbishydroxymethyl phosphate, 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, and phosphorus-containing bisphenol compounds with the following structural formulas (1) to (4);

[0018]

[0019] In this invention, polyhydroxyalkyl phosphate esters are used as chain transfer agents to prepare flame-retardant polycarbonate diols. Experiments have shown that during chain transfer polymerization, the polycarbonate diols can significantly increase their flame retardancy to UL 94V0 level by rapidly transferring the chain into the main chain and residing in the middle of the main chain.

[0020] The mass percentage of polyhydroxyalkyl phosphate esters is 0.5–1.5 wt% based on the total mass of epoxy compounds.

[0021] CO2 is introduced into the high-pressure reactor at a pressure of 1–5 MPa, and the polymerization reaction temperature is 50–100 °C.

[0022] The crude product obtained after polymerization needs to be purified by washing, filtering, and drying to remove impurities.

[0023] Preferred:

[0024] The preparation of the flame-retardant polycarbonate diol includes:

[0025] (1) Add the catalyst, epoxy compound, and polyhydroxyalkyl phosphate to the high-pressure reactor, introduce CO2 into the high-pressure reactor, and after bulk polymerization, perform depressurization and vacuuming.

[0026] (2) Under normal pressure and nitrogen protection, ethylene oxide and solvent are added to a high-pressure reactor, and flame-retardant polycarbonate ether polyol is obtained after reaction.

[0027] Experiments have shown that ethylene oxide can be introduced into the ends of polyol molecular chains. This transforms the hydroxyl groups at the ends of the polyols into primary hydroxyl groups, thereby increasing the reactivity of the polyols with isocyanates and improving the foaming effect of polyurethane materials. In contrast, polyurethanes made from flame-retardant polycarbonate diols that have not undergone step (2) have poor foaming effects, longer foaming times, and slightly reduced mechanical properties.

[0028] In step (2):

[0029] Based on the total mass of epoxy compounds, ethylene oxide typically accounts for 5-10 wt% of the total mass of epoxy compounds.

[0030] The solvent is selected from one or more of dimethyl carbonate, tetrahydrofuran, dichloromethane, and chloroform;

[0031] Based on the total mass of the epoxy compound, the solvent generally accounts for 30-40 wt% of the epoxy compound.

[0032] The reaction temperature is 50–100℃.

[0033] The crude product obtained after step (2) needs to be purified by washing, filtering, drying and removing impurities.

[0034] The halogen-free flame-retardant polyurethane foam composition disclosed in this invention:

[0035] The polyether polyol is selected from conventional types in the art, including but not limited to one or more of polypropylene oxide diol, polyethylene oxide diol, polytetrahydrofuran diol, tetrahydrofuran-propylene oxide copolymer diol, and polypropylene oxide triol; with a molecular weight of 400–2000 g / mol. The use of polyether polyols can improve the hardness of carbon dioxide-based polyols used in the preparation of polyurethane foam materials, increase the flexibility of the molecular chains, and improve the material's flexibility, mechanical properties, and impact resistance through cross-linking. The amount of polyether polyol introduced is adjusted according to the performance of the final product.

[0036] The diisocyanate is selected from conventional types in the art, including but not limited to one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), naphthalene 1,5-diisocyanate (NDI), trans-1,4-cyclohexyl diisocyanate (CHDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and terephthalic diisocyanate (PPDI); it is usually preferred to be an isocyanate containing a benzene ring structure, and particularly preferred to be a liquefiable mixed isocyanate, the amount of which is calculated according to the hydroxyl value of the composition.

[0037] Because it contains rigid benzene ring groups, it maintains a relatively stable structure at high temperatures, making it less prone to thermal decomposition or combustion. This helps slow down the thermal degradation rate of the material, reduce the release of flammable gases, and thus improve the flame retardant properties of the material. Simultaneously, during combustion, isocyanates containing benzene rings may form a char layer through complex chemical reactions. As a poor conductor of heat, it can insulate against heat and oxygen transfer, thereby slowing down the combustion rate. Furthermore, isocyanates may decompose at high temperatures to produce some non-flammable or flame-retardant gases (such as nitrogen and carbon dioxide), which can dilute the concentration of flammable gases and reduce the rate and intensity of the combustion reaction. The design of this invention, a phosphorus-containing polycarbonate diol, is also based on the consideration of nitrogen content in diisocyanates, thus directly utilizing the synergistic effect of phosphorus and nitrogen in the flame retardant process. The presence of phosphate esters, which form phosphoric acid after thermal decomposition, is beneficial for the carbonization of the entire material.

[0038] The small molecule polyols are selected from conventional types in the art, including but not limited to one or more of glycerol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-octanediol, 3-methyl-1-butanol, neopentanediol, triethylene glycol, trimethylolpropane, sorbitol, and pentaerythritol. Small molecule polyols can be used to adjust the hardness and strength of foamed materials and also have a significant impact on the elasticity and modulus of polyurethane foamed materials. During the foaming process, the reaction rate between the small molecule polyol and isocyanate affects the uniformity and stability of the foaming. An appropriate reaction rate can ensure that the foamed material has a uniform cell structure and good physical properties. Furthermore, small molecule polyols may also indirectly affect the foaming process by influencing parameters such as the viscosity of the reaction system.

[0039] The processing aids include antioxidants and / or ultraviolet absorbers.

[0040] The antioxidant is selected from conventional types in the art, including but not limited to one or more of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetra(bis-T-butylhydroxyhydrogenated cinnamic acid) ester, and tris(2,4-di-tert-butylphenyl) phosphite. The antioxidant prevents the aging of polyurethane and extends its service life by delaying or inhibiting the polymer oxidation process, and also prevents scorching during the foaming process and inhibits high-temperature yellowing.

[0041] The ultraviolet absorber is selected from conventional types in the art, including but not limited to one or more of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 2-hydroxy-4-n-octyloxybenzophenone, 4-methoxy-2-hydroxybenzophenone, 2-(5-chloro-2-benzyltriazolyl)-6-tert-butyl-p-cresol, and phenyl o-hydroxybenzoate. Organic polymers containing unsaturated chromophore functional groups can absorb ultraviolet radiation under sunlight. When the absorbed energy exceeds the bond energy, it can trigger chemical bond breakage, accelerating the oxidative degradation of the material and leading to material damage and failure. The introduction of ultraviolet absorbers can effectively slow down the ultraviolet aging of biodegradable fibers.

[0042] The foaming aid includes a foaming agent, a catalyst, and silicone oil;

[0043] The foaming agent is selected from one or more of water, cyclopentane, dichloromethane, azodicarbonamide, etc.

[0044] The catalyst is selected from one or more of dibutyltin dilaurate, triethylenediamine, bis(dimethylaminoethyl) ether, N,N-dimethylcyclohexylamine, and pentamethyldiethylenetriamine;

[0045] The mass ratio of foaming agent, catalyst and silicone oil is (3-15):1:(1-5).

[0046] Based on the above-mentioned preferred raw materials, further optimization is performed:

[0047] The halogen-free flame-retardant polyurethane foam composition, by weight, comprises the following raw materials:

[0048]

[0049]

[0050] This invention also discloses a method for preparing halogen-free flame-retardant polyurethane foam. The method involves mixing the raw materials according to their respective mass parts at room temperature and then foaming them. The preparation method is simple, controllable, and can be industrially scaled up and applied in practice.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. In the halogen-free flame-retardant foamed polyurethane composition provided by this invention, the phosphate ester structure is incorporated into the polycarbonate diol backbone via a rapid chain transfer polymerization reaction, acting as a macromolecular flame retardant. Compared to the traditional KOH method for preparing polyurethane from polyether polyols, which uses a high-temperature transesterification process, the phosphate ester diol is easily decomposed, making it difficult or impossible to introduce the phosphate ester structure into the molecular backbone. Simultaneously, this invention overcomes the shortcomings of traditional transesterification methods for polycarbonate polyol flame retardancy by employing a CO2 bulk polymerization method. This enhances the flame retardant properties of the material obtained from the reaction of carbon dioxide-based polyols with isocyanates. Due to the presence of phosphorus, the formed urethane bonds enhance the product's flame retardant properties through phosphorus-nitrogen synergy, allowing for applications requiring flame retardancy to be met with significantly less or no additional polymerization inhibitors.

[0053] 2. The halogen-free flame-retardant foamed polyurethane composition provided by the present invention overcomes the problem of high viscosity and difficult construction when carbon dioxide-based polyols are used in polyurethane materials. By introducing a small amount of special phosphorus-containing viscosity reducer, the viscosity of the composition during operation is significantly reduced, so that the ingredients can be mixed and operated at room temperature according to the composition formula, which is easy to foam; at the same time, it can also play a good flame-retardant role.

[0054] 3. The halogen-free flame-retardant foamed polyurethane composition provided by the present invention has low production cost, and many of the raw materials are commercially available. Flame-retardant polycarbonate diol can also be produced at low cost. Attached Figure Description

[0055] Figure 1 The stress-strain curve of the flame-retardant polyurethane foam material prepared in Example 1 is shown.

[0056] Figure 2 A photograph of the flame-retardant polyurethane foam prepared in Example 1. Detailed Implementation

[0057] The present invention will be described in further detail below with reference to embodiments and comparative examples, but the implementation of the present invention is not limited thereto.

[0058] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention were purchased commercially.

[0059] Example 1

[0060] Step 1: Add 0.2g of zinc-cobalt bimetallic cyanide catalyst, 10g of N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and 1200g of propylene oxide to a dry high-pressure reactor. At 100°C, introduce CO2 until the pressure inside the reactor reaches 5MPa. After bulk polymerization for 8 hours, remove the propylene oxide from the crude product by depressurization and vacuum. Then, under atmospheric pressure and nitrogen protection, add 20g of ethylene oxide and 500g of tetrahydrofuran to the reactor. After the viscosity decreases, continue the reaction at 80°C for 6 hours and then cool. The crude product is purified to obtain the final product, flame-retardant polycarbonate diol.

[0061] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3500 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.5.

[0062] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 30wt%, and the hydroxyl value was 35mgKOH / g.

[0063] Step 2: Mix 30 parts of flame-retardant polycarbonate diol prepared in Step 1 (unless otherwise specified, all raw materials in this invention are by weight), 70 parts of polyoxypropylene diol, 60 parts of diphenylmethane diisocyanate, 7 parts of (1-hydroxyethyl)phosphonate dimethyl ester, 3 parts of glycerol, 1 part of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1 part of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 1 part of dibutyltin dilaurate, 1 part of silicone oil, and 8 parts of water evenly and then foam after high-speed stirring for 20 seconds.

[0064] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores.

[0065] Example 2

[0066] The preparation process is basically the same as in Example 1, except that:

[0067] Replace the amount of flame-retardant polycarbonate diol in step two with 40 parts, and replace the amount of polyether polyol with 60 parts.

[0068] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores.

[0069] Example 3

[0070] The preparation process is basically the same as in Example 1, except that:

[0071] Replace the amount of flame-retardant polycarbonate diol in step two with 50 parts, and replace the amount of polyether polyol with 50 parts.

[0072] The flame-retardant foamed polyurethane prepared in this embodiment has poor elasticity and is relatively hard.

[0073] Example 4

[0074] The preparation process is basically the same as in Example 1, except that:

[0075] Replace the amount of flame-retardant polycarbonate diol in step two with 60 parts, and replace the amount of polyether polyol with 40 parts.

[0076] The flame-retardant foamed polyurethane prepared in this embodiment has poor elasticity and is relatively hard.

[0077] Example 5

[0078] The preparation process is basically the same as in Example 1, except that:

[0079] Replace the amount of flame-retardant polycarbonate diol in step two with 70 parts, and replace the amount of polyether polyol with 30 parts.

[0080] The flame-retardant foamed polyurethane prepared in this embodiment has poor elasticity and is relatively hard.

[0081] Example 6

[0082] Step 1: Add 0.2g of zinc-cobalt bimetallic cyanide catalyst, 10g of N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and 1200g of propylene oxide to a dry high-pressure reactor. At 80°C, introduce CO2 until the pressure inside the reactor reaches 4MPa. After bulk polymerization for 6 hours, remove the propylene oxide from the crude product by depressurization and vacuum. Then, under atmospheric pressure and nitrogen protection, add 20g of ethylene oxide and 500g of tetrahydrofuran to the reactor. After the viscosity decreases, continue the reaction at 80°C for 6 hours and then cool. The crude product is purified to obtain the final product, flame-retardant polycarbonate diol.

[0083] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3000 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.8.

[0084] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 20wt%, and the hydroxyl value was 30mgKOH / g.

[0085] Step 2: Mix 30 parts of flame-retardant polycarbonate diol, 70 parts of polyoxypropylene diol, 60 parts of diphenylmethane diisocyanate, 7 parts of (1-hydroxyethyl)phosphonate dimethyl ester, 3 parts of glycerol, 1 part of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1 part of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 1 part of dibutyltin dilaurate, 1 part of silicone oil, and 8 parts of water evenly and then foam after high-speed stirring for 20 seconds.

[0086] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0087] Example 7

[0088] The preparation process is basically the same as in Example 6, with the only difference being:

[0089] Replace the amount of diphenylmethane diisocyanate used in step two with 45 parts.

[0090] The flame-retardant foamed polyurethane prepared in this embodiment has poor foaming effect.

[0091] Example 8

[0092] The preparation process is basically the same as in Example 6, with the only difference being:

[0093] Replace the amount of diphenylmethane diisocyanate used in step two with 55 parts.

[0094] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores.

[0095] Example 9

[0096] The preparation process is basically the same as in Example 1, with the only difference being:

[0097] Replace the amount of (1-hydroxyethyl)phosphonic acid dimethyl ester in step two with 2 parts.

[0098] The flame-retardant polyurethane foam prepared in this embodiment has uneven foaming.

[0099] Example 10

[0100] The preparation process is basically the same as in Example 1, with the only difference being:

[0101] Replace the amount of (1-hydroxyethyl)phosphonic acid dimethyl ester in step two with 4 parts.

[0102] The flame-retardant polyurethane foam prepared in this embodiment has uneven foaming.

[0103] Example 11

[0104] The preparation process is basically the same as in Example 1, with the only difference being:

[0105] Replace the amount of (1-hydroxyethyl)phosphonic acid dimethyl ester in step two with 6 parts.

[0106] The flame-retardant foamed polyurethane prepared in this embodiment has uniform, soft and dense pores, similar to that in Example 1.

[0107] Example 12

[0108] The preparation process is basically the same as in Example 1, with the only difference being:

[0109] Replace the amount of (1-hydroxyethyl)phosphonic acid dimethyl ester in step two with 10 parts.

[0110] The flame-retardant foamed polyurethane prepared in this embodiment has uniform, soft and dense pores, similar to that in Example 1.

[0111] Example 13

[0112] The preparation process is basically the same as in Example 1, with the only difference being:

[0113] Replace N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester in step one with an equal mass of dihydroxyethylbishydroxymethyl phosphate.

[0114] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3200 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.4.

[0115] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 32wt%, and the hydroxyl value was 38mgKOH / g.

[0116] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0117] Example 14

[0118] The preparation process is basically the same as in Example 1, with the only difference being:

[0119] Replace the diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate in step one with an equal mass of a phosphorus-containing bisphenol compound (structural formula as shown in 1).

[0120] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3800 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.8.

[0121] through 1H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 28wt%, and the hydroxyl value was 33mgKOH / g.

[0122] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0123] Example 15

[0124] The preparation process is basically the same as in Example 1, with the only difference being:

[0125] Replace the diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate in step one with an equal mass of a phosphorus-containing bisphenol compound (structural formula as shown in 2).

[0126] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3700 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.7.

[0127] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 29wt%, and the hydroxyl value was 34mgKOH / g.

[0128] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0129] Example 16

[0130] The preparation process is basically the same as in Example 1, with the only difference being:

[0131] Replace the diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate in step one with an equal mass of a phosphorus-containing bisphenol compound (structural formula as shown in 3).

[0132] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3800 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.8.

[0133] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 28wt%, and the hydroxyl value was 33mgKOH / g.

[0134] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0135] Example 17

[0136] The preparation process is basically the same as in Example 1, with the only difference being:

[0137] Replace the diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate in step one with an equal mass of a phosphorus-containing bisphenol compound (structural formula as shown in 4).

[0138] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3900 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.9.

[0139] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 28wt%, and the hydroxyl value was 33mgKOH / g.

[0140] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0141] Example 18

[0142] The preparation process is basically the same as in Example 1, with the only difference being:

[0143] Replace the (1-hydroxyethyl)phosphonate dimethyl ester in step two with an equal mass of hydroxymethylphosphonate diethyl ester.

[0144] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0145] Example 19

[0146] The preparation process is basically the same as in Example 1, with the only difference being:

[0147] Replace the (1-hydroxyethyl)phosphonate dimethyl ester in step two with an equal mass of 2-hydroxyethylphosphonate dimethyl ester.

[0148] The flame-retardant polyurethane foam prepared in this embodiment has uniform, soft, and fine pores, similar to that in Example 1.

[0149] Example 20

[0150] The preparation process is basically the same as in Example 1, with the only difference being:

[0151] In step one, 0.2g of zinc-cobalt bimetallic cyanide catalyst, 10g of N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, and 1200g of propylene oxide were added to a dry high-pressure reactor. At 100°C, CO2 was introduced until the pressure inside the reactor reached 5MPa. After bulk polymerization for 8 hours, polycarbonate diol was obtained. The crude product was then depressurized and vacuumed to remove propylene oxide. The product was then directly washed, filtered, dried, and purified to remove impurities.

[0152] The molecular weight of the flame-retardant polycarbonate diol prepared in step one was determined to be 3500 g / mol by gel permeation chromatography, and the molecular weight distribution was 1.5.

[0153] through 1 H NMR testing showed that the CO2 mass fraction in the flame-retardant polycarbonate diol was 30wt%, and the hydroxyl value was 20mgKOH / g.

[0154] The flame-retardant polyurethane foam prepared in this embodiment has a poorer foaming effect compared with that in Example 1.

[0155] Comparative Example 1

[0156] The preparation process is basically the same as in Example 1, with the only difference being:

[0157] In step (1), N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester was not added during the preparation of the polymer, and polycarbonate diol was obtained.

[0158] The polyurethane foam prepared in this comparative example has uniform, soft, and fine pores.

[0159] Comparative Example 2

[0160] The preparation process is basically the same as in Example 1, with the only difference being:

[0161] (1-hydroxyethyl)phosphonic acid dimethyl ester was not added in step two.

[0162] The foamed polyurethane prepared in this comparative example exhibits uneven foaming.

[0163] Comparative Example 3

[0164] The preparation process is basically the same as in Example 1, with the only difference being:

[0165] In step two, (1-hydroxyethyl)phosphonate dimethyl ester is replaced with an equal mass of dioctyl phthalate.

[0166] The foamed polyurethane prepared in this comparative example exhibited uneven foaming and poor performance.

[0167] Comparative Example 4

[0168] The preparation process is basically the same as that in Comparative Example 1, with the only difference being:

[0169] In step two, the mass of (1-hydroxyethyl)phosphonic acid dimethyl ester is replaced with 30 parts.

[0170] The foamed polyurethane prepared in this comparative example exhibited uneven foaming and poor performance.

[0171] Comparative Example 5

[0172] The preparation process is basically the same as in Example 1, with the only difference being:

[0173] Replace the amount of diphenylmethane diisocyanate used in step two with 25 parts.

[0174] The foamed polyurethane prepared in this comparative example failed to foam.

[0175] Comparative Example 6

[0176] The preparation process is basically the same as in Example 1, with the only difference being:

[0177] Replace the amount of diphenylmethane diisocyanate used in step two with 35 parts.

[0178] The foamed polyurethane prepared in this comparative example failed to foam.

[0179] Performance testing:

[0180] The foaming properties, flame retardant properties (GB / T26700-2011), and mechanical properties (GB / T 9641) of the polyurethane foams prepared in each embodiment and comparative example are listed in Table 1 below.

[0181] Table 1

[0182]

[0183]

[0184] The above-described embodiments are preferred embodiments, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A halogen-free flame-retardant polyurethane foam composition, characterized in that, By weight, the raw material composition includes: 30-40 parts of flame-retardant polycarbonate diol; 60-70 parts of polyether polyol; 55-65 parts of diisocyanate; 1-5 parts of small molecule polyols; 5-10 parts of viscosity reducer; Processing aids: 1-5 parts; 1-15 parts of foaming agent; The preparation of the flame-retardant polycarbonate diol includes: (1) Add the catalyst, epoxy compound, and polyhydroxyalkyl phosphate to the high-pressure reactor, introduce CO2 into the high-pressure reactor, and after bulk polymerization, perform depressurization and vacuum treatment. The polyhydroxyalkyl phosphate is selected from one or more of the following: N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, dihydroxyethyl bishydroxymethyl phosphate, 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, and phosphorus-containing bisphenol compounds with the following structural formulas (1) to (4); （1）； （2）； （3）； （4）； (2) Under normal pressure and nitrogen protection, ethylene oxide and solvent are added to a high-pressure reactor, and flame-retardant polycarbonate ether polyol is obtained after reaction; The viscosity reducer is selected from one or more of (1-hydroxyethyl)phosphonate dimethyl ester, hydroxymethylphosphonate diethyl ester, and 2-hydroxyethylphosphonate dimethyl ester.

2. The halogen-free flame-retardant polyurethane foam composition according to claim 1, characterized in that: The catalyst is selected from zinc-cobalt bimetallic cyanide catalysts or supported zinc-cobalt bimetallic cyanide catalysts; The epoxy compound is selected from propylene oxide and / or butane oxide; Based on the total mass of epoxy compounds, the catalyst accounts for 0.01~0.50 wt% by mass, and the polyhydroxyalkyl phosphate accounts for 0.5~1.5 wt% by mass.

3. The halogen-free flame-retardant polyurethane foam composition according to claim 1, characterized in that: Access The CO2 pressure inside the high-pressure reactor is 1~5 MPa, and the polymerization reaction temperature is 50~100℃.

4. The halogen-free flame-retardant polyurethane foam composition according to claim 1, characterized in that: The polyether polyol is selected from one or more of polypropylene oxide diol, polyethylene oxide diol, polytetrahydrofuran diol, tetrahydrofuran-propylene oxide copolydiol, and polypropylene oxide triol; The diisocyanate is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, naphthalene 1,5-diisocyanate, trans-1,4-cyclohexyl diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and terephthalic diisocyanate. The small molecule polyol is selected from one or more of glycerol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-octanediol, neopentanediol, triethylene glycol, trimethylolpropane, sorbitol, and pentaerythritol. The processing aids include antioxidants and / or ultraviolet absorbers.

5. The halogen-free flame-retardant polyurethane foam composition according to claim 1, characterized in that: The foaming aid includes a foaming agent, a catalyst, and silicone oil; The foaming agent is selected from one or more of water, cyclopentane, dichloromethane, and azodicarbonamide; The catalyst is selected from one or more of dibutyltin dilaurate, triethylenediamine, bis(dimethylaminoethyl) ether, N,N-dimethylcyclohexylamine, and pentamethyldiethylenetriamine; The mass ratio of foaming agent, catalyst and silicone oil is (3~15):1:(1~5).

6. The halogen-free flame-retardant polyurethane foam composition according to claim 1, characterized in that, In step (2): Based on the total mass of the epoxy compounds, ethylene oxide accounts for 5-10 wt% of the total mass. The solvent is selected from one or more of dimethyl carbonate, tetrahydrofuran, dichloromethane, and chloroform; The solvent accounts for 30-40 wt% of the total mass of the epoxy compound. The reaction temperature is 50~100 ℃.

7. A method for preparing halogen-free flame-retardant polyurethane foam, characterized in that, The halogen-free flame-retardant polyurethane foam composition according to any one of claims 1 to 6 is foamed after the raw materials are mixed evenly at room temperature according to their respective mass parts.

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