Polymeric mdi compositions, polyurethane rigid foam materials and methods for making the same

Abstract

The application relates to a polymeric MDI composition, a polyurethane rigid foam material and a preparation method thereof. The polymeric MDI composition comprises a polymeric MDI and a flame-retardant component; the MDI has a polymeric average functionality of 2.7-3; the flame-retardant component comprises an isocyanate polymer containing active structures and a liquid flame retardant, and the active structures comprise one or more of an aromatic imide ring, an oxazolidinone ring and an isocyanurate ring. The polymeric MDI composition is applied to the preparation of a polyurethane rigid foam material, and good flame-retardant performance and dimensional stability can be achieved.

Description

Technical Field

[0001] This application relates to the field of polyurethane technology, and in particular to a polymeric MDI composition, a rigid polyurethane foam material, and a method for preparing the same. Background Technology

[0002] Rigid polyurethane foam (PU foam), also known as rigid polyurethane foam, is made primarily from polymeric MDI (Polymeric MDI, PMDI, commonly known as "black material," chemically named polymethylene polyphenyl isocyanate). Currently, rigid polyurethane foam is widely used in building energy conservation, cold chain logistics, petrochemical insulation, aerospace, and other fields due to its low density, low thermal conductivity, high specific strength, and excellent bonding properties. With the continuous expansion of application scenarios, related fields are placing more stringent requirements on the flame retardancy, dimensional stability, and mechanical properties of rigid polyurethane foam.

[0003] However, the molecular structure of traditional rigid polyurethane foam contains a large number of urethane groups, which have poor thermal stability and are prone to thermal degradation in high-temperature environments, leading to the decay of material mechanical properties, dimensional shrinkage and deformation. Furthermore, its flame retardant properties are difficult to meet the requirements of high-end application scenarios, which greatly limits its long-term application under harsh working conditions.

[0004] To improve the flame retardant properties of rigid polyurethane foam, traditional methods mainly include adding flame retardants and intrinsic flame retardancy. Adding flame retardants, through physical blending, is a simple method that can achieve good flame retardant effects at higher addition levels. However, it is prone to migration and uneven distribution, and can degrade the mechanical properties and dimensional stability of the foam. Intrinsic flame retardancy involves chemically bonding flame-retardant groups into the molecular chain, which can solve migration and dispersion problems, but its improvement on the mechanical properties and dimensional stability of the foam is limited. For example, some studies have constructed rigid, heat-resistant heterocyclic structures such as imide rings, oxazolidinone rings, and isocyanurate rings in the polyurethane system to improve the flame retardant properties of the foam material. However, the formation of rigid structures is often accompanied by a sharp increase in material viscosity, making material mixing difficult, resulting in poor foaming processability, foam shrinkage, increased brittleness, or surface powdering, and leading to poor dimensional stability of the prepared rigid polyurethane foam. Summary of the Invention

[0005] Based on this, this application provides a polymeric MDI composition, a rigid polyurethane foam material, and a method for preparing the same, which can achieve both good flame retardant properties and dimensional stability.

[0006] A first aspect of this application provides a polymeric MDI composition comprising polymeric MDI and a flame-retardant component;

[0007] The average functionality of the polymeric MDI is 2.7~3;

[0008] The flame-retardant component includes an isocyanate polymer with an active structure and a liquid flame retardant, wherein the active structure includes one or more of an aromatic imide ring, an oxazolidinone ring, and an isocyanurate ring.

[0009] In some embodiments, the polymeric MDI composition comprises, by weight percentage:

[0010] The polymeric MDI is 75%~90%.

[0011] The flame retardant component is 10%~25%.

[0012] In some embodiments, the polymeric MDI comprises:

[0013] The first polymeric MDI has a functionality of <2.9;

[0014] The second polymerized MDI has a functionality of 2.9 to 3.1.

[0015] In some embodiments, the polymeric MDI composition comprises, by weight percentage:

[0016] The first polymeric MDI is 20%~40%.

[0017] The second polymerized MDI is 35%~55%, and

[0018] The flame retardant component is 10%~25%;

[0019] The sum of the mass percentages of the first polymeric MDI and the second polymeric MDI is 75% to 90%.

[0020] In some embodiments, the flame-retardant component is prepared by mixing a diisocyanate monomer with a liquid flame retardant and undergoing a first polymerization reaction; or...

[0021] The flame retardant component is prepared by mixing diisocyanate monomers, active compounds and liquid flame retardants to carry out a second polymerization reaction; the active compound includes one or two of aromatic anhydrides and epoxy resins.

[0022] In some embodiments, the flame-retardant component has one or more of the following characteristics:

[0023] (1) The diisocyanate monomer includes one or more of aromatic diisocyanate monomers, aliphatic diisocyanate monomers and alicyclic diisocyanate monomers, and may optionally include one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isoflurone diisocyanate;

[0024] (2) Based on the total mass of the flame retardant components, the amount of diisocyanate monomer added is 10% to 90%, and can be selected as 30% to 60%;

[0025] (3) The aromatic anhydride includes one or more of phthalic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride and biphenyl tetracarboxylic dianhydride;

[0026] (4) The amount of aromatic anhydride added is 0% to 50% based on the total mass of the flame retardant components, and can be selected as 0% to 30%;

[0027] (5) The epoxy resin includes one or more of bisphenol A type epoxy resin, biphenyl type epoxy resin and DOPO type epoxy resin;

[0028] (6) The amount of epoxy resin added is 0% to 40% based on the total mass of the flame retardant components, and can be selected as 0% to 20%;

[0029] (7) The liquid flame retardant includes one or more of phosphorus-based flame retardants, chlorine-based flame retardants and bromine-based flame retardants, and optionally includes phosphorus-based flame retardants, and further optionally includes one or more of tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, dimethyl methyl phosphate, trimethyl phosphate, triethyl phosphate and triphenyl phosphate;

[0030] (8) The amount of liquid flame retardant added is 10% to 90% based on the total mass of the flame retardant components, and can be selected as 10% to 40%;

[0031] (9) The conditions for the first polymerization reaction and the second polymerization reaction each independently include: the reaction is carried out in the presence of a catalyst, and after the reaction is completed, an inhibitor is added;

[0032] Optionally, the catalyst comprises one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, tris(dimethylaminopropyl)hexahydrotriazine, potassium isooctanoate, and potassium acetate;

[0033] Optionally, the amount of catalyst added is 500ppm to 3000ppm, or optionally 1000ppm to 2000ppm, based on the mass of the diisocyanate monomer.

[0034] Optionally, the polymerization inhibitor includes one or more of benzoyl chloride, benzenesulfonyl chloride, and p-toluenesulfonyl chloride;

[0035] Optionally, the amount of the polymerization inhibitor added is 2000ppm to 4000ppm based on the mass of the diisocyanate monomer;

[0036] Optionally, the reaction temperature is 50℃~130℃, or optionally 70℃~110℃;

[0037] Optionally, the reaction time is 3h~8h, or 4h~6h.

[0038] In some embodiments, the second polymeric MDI has one or more of the following features:

[0039] (1) The NCO content is 31.5%~33%;

[0040] (2) The viscosity at 25℃ is 90cP~140cP.

[0041] In some embodiments, the polymeric MDI composition has one or more of the following characteristics:

[0042] (1) The NCO content is 25%~31%, and 27%~30% can be selected;

[0043] (2) The viscosity at 25℃ is 100cP~600cP, and can be selected as 200cP~400cP.

[0044] A second aspect of this application provides a rigid polyurethane foam material, the raw materials of which include a polyisocyanate component, a polyol component and a foaming agent;

[0045] The polyisocyanate component includes the polymeric MDI composition described in the first aspect.

[0046] In some embodiments, the mass ratio of the polyisocyanate component, the polyol component, and the foaming agent is (160~210):(80~130):(5~20).

[0047] In some embodiments, the foaming agent includes one or more of cyclopentane, isopentane, and n-pentane.

[0048] A third aspect of this application provides a method for preparing the rigid polyurethane foam material described in the second aspect, comprising the following steps:

[0049] The polyisocyanate component, the polyol component, and the foaming agent are mixed and stirred to foam, thereby preparing the rigid polyurethane foam material.

[0050] Optionally, the stirring and foaming conditions include: a rotation speed of 2000 r / min to 3000 r / min and a time of 3 s to 7 s.

[0051] The aforementioned polymeric MDI composition is a blend of polymeric MDI with an average functionality within a suitable range and a flame-retardant component with a specific structure. The polymeric MDI with an appropriate average functionality range can regulate its reaction process during the foaming of rigid polyurethane foam. Based on this, an isocyanate polymer with an active structure and a liquid flame retardant are added as flame-retardant components. These components exhibit good solubility and dispersibility in the polymeric MDI, effectively improving the flame-retardant properties of the rigid polyurethane foam. The blend of these two components achieves excellent flame-retardant performance while also maintaining the dimensional stability of the rigid polyurethane foam. Further research has also found that the aforementioned polymeric MDI composition can also maintain the compressive strength of the rigid polyurethane foam.

[0052] The polyurethane rigid foam material prepared by the above-mentioned polymerized MDI composition is suitable for rigid foam fields with stringent requirements for flame retardancy, dimensional stability and mechanical properties, such as building insulation, cold chain equipment, and transportation vehicles. Detailed Implementation

[0053] The following detailed description, in conjunction with specific embodiments, further illustrates the polymeric MDI composition, rigid polyurethane foam material, and preparation method thereof of this application. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0055] As used herein, the terms “and / or,” “or / and,” and “and / or” may include any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all the related listed items.

[0056] In this article, "one or more" refers to any one, two or more of the listed items.

[0057] In this application, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0058] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0059] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0060] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0061] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0062] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0063] In this application, room temperature generally refers to 4℃~30℃, and preferably 20±5℃.

[0064] In this application, "NCO content" refers to the mass percentage of NCO groups in the overall material.

[0065] Some embodiments of this application provide a polymeric MDI composition, comprising polymeric MDI and a flame-retardant component;

[0066] The average functionality of the polymeric MDI is 2.7~3;

[0067] The flame-retardant component includes an isocyanate polymer with an active structure and a liquid flame retardant, wherein the active structure includes one or more of an aromatic imide ring, an oxazolidinone ring, and an isocyanurate ring.

[0068] Understandably, "isocyanate polymers" refer to oligomers formed by two or more isocyanate monomer molecules linked together by chemical bonds. They are also commonly called polymeric isocyanates or polyisocyanates.

[0069] Understandably, when there is only one type of polymeric MDI, the average functionality of the polymeric MDI is the functionality of that polymeric MDI; when there are two or more types of polymeric MDI, the weighted average of the functionality of each polymeric MDI is taken. Taking two types of polymeric MDI as an example, if the functionality of the first polymeric MDI is A and its mass percentage in the total polymeric MDI is a%, and the functionality of the second polymeric MDI is B and its mass percentage in the total polymeric MDI is b%, then the average functionality of the total polymeric MDI = A * a% + B * b.

[0070] Specifically, the average functionality of the polymeric MDI includes, but is not limited to, 2.7, 2.75, 2.79, 2.8, 2.84, 2.85, 2.9, 2.92, 2.96, 3, or any two of the foregoing.

[0071] In some embodiments, the polymeric MDI composition comprises, by weight percentage:

[0072] The polymeric MDI is 75%~90%.

[0073] The flame retardant component is 10%~25%.

[0074] Specifically, the mass percentage of polymeric MDI includes, but is not limited to, 75%, 80%, 85%, 90%, or any two of the foregoing.

[0075] Specifically, the mass percentage of the flame retardant component includes, but is not limited to: 10%, 15%, 20%, 25%, or any combination thereof.

[0076] In some embodiments, the polymeric MDI comprises:

[0077] The first polymeric MDI has a functionality of <2.9;

[0078] The second polymerized MDI has a functionality of 2.9 to 3.1.

[0079] By combining first-polymerized MDI and second-polymerized MDI with specific functionalities, the reaction process in the foaming of rigid polyurethane foam can be better controlled, and the compatibility of flame-retardant components in the system can be improved, thus better balancing excellent flame-retardant properties and compressive strength. Furthermore, the second-polymerized MDI with higher functionality can be recycled from traditional MDI production processes, achieving high-value utilization of industrial byproducts and reducing production costs.

[0080] Specifically, the functionality of the first polymeric MDI includes, but is not limited to, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.86, 2.89 or any two of the foregoing.

[0081] Specifically, the functionality of the second polymeric MDI includes, but is not limited to, 2.9, 2.95, 3, 3.05, 3.1 or any two of the foregoing.

[0082] In some embodiments, the polymeric MDI composition comprises, by weight percentage:

[0083] The first polymeric MDI is 20%~40%.

[0084] The second polymerized MDI is 35%~55%, and

[0085] The flame retardant component is 10%~25%;

[0086] The sum of the mass percentages of the first polymeric MDI and the second polymeric MDI is 75% to 90%.

[0087] Specifically, the mass percentage of the first polymeric MDI includes, but is not limited to, 20%, 25%, 30%, 35%, 40%, or any two of the foregoing.

[0088] Specifically, the mass percentage of the second polymeric MDI includes, but is not limited to, 35%, 40%, 45%, 50%, 55%, or any range between the two mentioned above.

[0089] Specifically, the mass percentage of the flame retardant component includes, but is not limited to: 10%, 15%, 20%, 25%, or any combination thereof.

[0090] In some embodiments, the flame retardant component is prepared by mixing a diisocyanate monomer with a liquid flame retardant to carry out a first polymerization reaction; or, the flame retardant component is prepared by mixing a diisocyanate monomer, an active compound, and a liquid flame retardant to carry out a second polymerization reaction; the active compound includes one or both of aromatic anhydrides and epoxy resins.

[0091] Furthermore, the flame retardant component is prepared by mixing diisocyanate monomer, aromatic anhydride, epoxy resin and liquid flame retardant to carry out a second polymerization reaction.

[0092] Understandably, the aromatic imide ring is formed by the polymerization of a diisocyanate monomer with an aromatic anhydride.

[0093] Understandably, the oxazolidinone ring is formed by polymerization of a diisocyanate monomer with an epoxy resin.

[0094] Understandably, the isocyanurate ring is formed by the polymerization of diisocyanate monomers.

[0095] Without limitation, the diisocyanate monomer includes one or more of aromatic diisocyanate monomers, aliphatic diisocyanate monomers, and alicyclic diisocyanate monomers. In some embodiments, one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isoflurane diisocyanate are used.

[0096] In some embodiments, the amount of diisocyanate monomer added is 10% to 90% based on the total mass of the flame-retardant component. Specifically, the amount of diisocyanate monomer added includes, but is not limited to: 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or any range between the foregoing. Further, the amount of diisocyanate monomer added is 30% to 60% based on the total mass of the flame-retardant component.

[0097] In some embodiments, the aromatic anhydride includes one or more of phthalic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and biphenyl tetracarboxylic dianhydride.

[0098] In some embodiments, the amount of aromatic anhydride added is 0% to 50% based on the total mass of the flame-retardant components. Specifically, the amount of aromatic anhydride added includes, but is not limited to: 0%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any range between the foregoing. Further, the amount of aromatic anhydride added is 0% to 30% based on the total mass of the flame-retardant components.

[0099] In some embodiments, the epoxy resin includes one or more of bisphenol A type epoxy resin, biphenyl type epoxy resin, and DOPO type epoxy resin.

[0100] In some embodiments, the amount of epoxy resin added is 0% to 40% based on the total mass of the flame-retardant components. Specifically, the amount of epoxy resin added includes, but is not limited to: 0%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any range between the foregoing. Further, the amount of epoxy resin added is 0% to 20% based on the total mass of the flame-retardant components.

[0101] Without limitation, the liquid flame retardant includes one or more of phosphorus-based, chlorine-based, and bromine-based flame retardants.

[0102] In some embodiments, the liquid flame retardant comprises a phosphorus-based flame retardant. Further, the liquid flame retardant comprises one or more of tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, dimethyl methyl phosphate, trimethyl phosphate, triethyl phosphate, and triphenyl phosphate.

[0103] In some embodiments, the amount of liquid flame retardant added is 10% to 90% based on the total mass of the flame-retardant components. Specifically, the amount of liquid flame retardant added includes, but is not limited to: 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or any range between the foregoing. Further, the amount of liquid flame retardant added is 10% to 40% based on the total mass of the flame-retardant components.

[0104] In some embodiments, the conditions for the first polymerization reaction and the second polymerization reaction each independently include: carrying out the reaction in the presence of a catalyst, and after the reaction is completed, adding a polymerization inhibitor;

[0105] Without limitation, the catalyst includes one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, tris(dimethylaminopropyl)hexahydrotriazine, potassium isooctanoate, and potassium acetate.

[0106] In some embodiments, the amount of catalyst added is 500 ppm to 3000 ppm based on the mass of the diisocyanate monomer. Specifically, the amount of catalyst added includes, but is not limited to, 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, or any range between the foregoing. Further, the amount of catalyst added is 1000 ppm to 2000 ppm based on the mass of the diisocyanate monomer.

[0107] Without limitation, the polymerization inhibitor includes one or more of benzoyl chloride, benzenesulfonyl chloride, and p-toluenesulfonyl chloride.

[0108] In some embodiments, the amount of the polymerization inhibitor added is 2000 ppm to 4000 ppm based on the mass of the diisocyanate monomer. Specifically, the amount of the polymerization inhibitor added includes, but is not limited to, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, 5000 ppm, or any range between the foregoing.

[0109] In some embodiments, the reaction temperature is 50°C to 130°C. Specifically, the reaction temperature includes, but is not limited to, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or any range between the foregoing. Further, the reaction temperature is 70°C to 110°C.

[0110] In some embodiments, the reaction time is 3 to 8 hours. Specifically, the reaction time includes, but is not limited to: 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, and 8 hours. Further, the reaction time is 4 to 6 hours.

[0111] In some embodiments, the second polymeric MDI has one or more of the following features:

[0112] (1) The NCO content is 31.5%~33%;

[0113] (2) The viscosity at 25℃ is 90cP~140cP.

[0114] Without limitation, the first aggregated MDI has one or more of the following features:

[0115] (1) The NCO content is 30.5%~32%;

[0116] (2) The viscosity at 25℃ is 100cP~700cP.

[0117] In some embodiments, the polymeric MDI composition has one or more of the following characteristics:

[0118] (1) The NCO content is 25%~31%, and 27%~30% can be selected;

[0119] (2) The viscosity at 25℃ is 100cP~600cP, and can be selected as 200cP~400cP.

[0120] In addition, the polymeric MDI composition is a transparent liquid at room temperature and is light brown in color.

[0121] Without limitation, the preparation method of the polymeric MDI composition may involve simply mixing the components, and stirring may be performed if necessary to ensure thorough mixing. The stirring conditions can be adjusted by those skilled in the art. Heating may also be performed if necessary, for example, to 50°C to 70°C, to facilitate uniform mixing.

[0122] In other embodiments of this application, a rigid polyurethane foam material is provided, the raw materials of which include a polyisocyanate component, a polyol component and a foaming agent; the polyisocyanate component comprises the polymeric MDI composition as described above.

[0123] Understandably, the polyurethane rigid foam material is an intrinsically flame-retardant polyurethane rigid foam material.

[0124] In some embodiments, the mass ratio of the polyisocyanate component, the polyol component, and the foaming agent is (160~210):(80~130):(5~20).

[0125] Without limitation, the polyol component includes polyether polyols and / or polyester polyols. Further, by mass percentage, the polyol component includes: 35%~45% polyether polyol, 50%~60% polyester polyol, 1%~2% catalyst, 2%~3% chain extender, and 1%~2% silicone oil.

[0126] Without limitation, the foaming agent includes one or more of cyclopentane, isopentane, and n-pentane.

[0127] Other embodiments of this application provide a method for preparing the polyurethane rigid foam material as described above, comprising the following steps:

[0128] The polyisocyanate component, the polyol component, and the foaming agent are mixed and stirred to foam, thereby preparing the rigid polyurethane foam material.

[0129] In some embodiments, the stirring and foaming conditions include a rotation speed of 2000 r / min to 3000 r / min and a time of 3 s to 7 s.

[0130] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0131] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0132] The first polymerized MDI products, PM-130, PM-200, PM-400, and PM-700, are from Wanhua Chemical. Among them, PM-130 has an NCO content of 31.6%, a viscosity of 130 cP at 25°C, and a functionality of 2.6; PM-200 has an NCO content of 31.3%, a viscosity of 200 cP at 25°C, and a functionality of 2.7; PM-400 has an NCO content of 31%, a viscosity of 400 cP at 25°C, and a functionality of 2.8; and PM-700 has an NCO content of 30.8%, a viscosity of 700 cP at 25°C, and a functionality of 2.86.

[0133] The second type of polymeric MDI: high-functionality polymeric MDI, obtained from Wanhua Chemical's MDI production unit, has an NCO content of 32.6%, a viscosity of 120 cP at 25°C, and a functionality of 3. High-functionality polymeric MDI can be prepared by the following method: PM-700 and n-hexane are mixed in a 1:2 ratio, extracted and separated at room temperature for 2 hours, and the supernatant is distilled under reduced pressure at 100°C and 40 kPa for 30 minutes, followed by N2 stripping for 3 hours to obtain high-functionality polymeric MDI.

[0134] Diisocyanate monomers: TDI-100 and TDI-80 are from Wanhua Chemical.

[0135] Example 1

[0136] (1) Preparation of flame retardant components:

[0137] 1 kg TDI-100, 0.2 kg pyromellitic dianhydride, 0.2 kg DOPO type epoxy resin and 0.6 kg triethyl phosphate were added to a reactor and stirred until homogeneous. Then, 1500 ppm of catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added dropwise. The amount of catalyst was based on the total mass of TDI-100, and the same amount of polymerization inhibitor was added. The mixture was heated to 80°C and stirred for 5 hours. Then, 3000 ppm of polymerization inhibitor benzoyl chloride was added and stirred for 30 minutes before being discharged to obtain the flame retardant component.

[0138] (2) Preparation of polymeric MDI composition:

[0139] 1.2 kg PM-400, 2 kg high-functionality polymeric MDI (both with an average functionality of 2.92) and 0.8 kg flame retardant component were added to a reactor, heated to 60°C and stirred until homogeneous to obtain a polymeric MDI composition, which was designated as component A.

[0140] (3) Preparation of rigid polyurethane foam materials:

[0141] By mass percentage, component B consists of: polyether polyol S3007 40%, polyester polyol WRP-320 55%, catalyst PC-5 1.5%, chain extender DEG 2.5%, and silicone oil 8805 1%.

[0142] Mix 100g of component B and 9g of foaming agent n-pentane evenly, then add 180g of component A, stir at 2000rpm for 5s, and obtain rigid polyurethane foam material after the foam has matured.

[0143] Example 2

[0144] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in the preparation of the flame retardant component in step (1), 1.2 kg TDI-100, 0.2 kg pyromellitic dianhydride, 0.4 kg DOPO type epoxy resin and 0.2 kg triethyl phosphate are used; correspondingly, in the preparation of the polymeric MDI composition in step (2), 1.6 kg PM-200, 1.4 kg high-functionality polymeric MDI (the average functionality of the two is 2.84) and 1 kg flame retardant component are used so that the overall NCO content of the polymeric MDI composition is similar to that in Example 1.

[0145] Example 3

[0146] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in the preparation of the flame retardant component in step (1), 0.6 kg TDI-100, 0.6 kg pyromellitic dianhydride, 0.2 kg DOPO type epoxy resin and 0.6 kg triethyl phosphate are used; correspondingly, in the preparation of the polymeric MDI composition in step (2), 1.4 kg PM-400, 2.2 kg high-functionality polymeric MDI (the average functionality of the two is 2.92) and 0.4 kg flame retardant component are used so that the overall NCO content of the polymeric MDI composition is similar to that in Example 1.

[0147] Example 4

[0148] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (1) the preparation of the flame retardant component, 1.2 kg TDI-80 and 0.8 kg triethyl phosphate are added to the reactor.

[0149] Example 5

[0150] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in the preparation of the flame retardant component in step (1), 0.8 kg TDI-80, 0.4 kg pyromellitic dianhydride, 0.2 kg DOPO type epoxy resin and 0.6 kg triethyl phosphate are used; correspondingly, in the preparation of the polymeric MDI composition in step (2), 1 kg PM-200, 2 kg high-functionality polymeric MDI (the average functionality of the two is 2.9) and 1 kg flame retardant component are used so that the overall NCO content of the polymeric MDI composition is similar to that in Example 1.

[0151] Example 6

[0152] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (1) the preparation of the flame retardant component, 1.8 kg TDI-80 and 0.2 kg triethyl phosphate are added to the reactor.

[0153] Example 7

[0154] The preparation method of polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (1) the preparation of flame retardant components, 0.2 kg TDI-80 and 1.8 kg triethyl phosphate are added to the reactor.

[0155] Example 8

[0156] The preparation method of polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (1) the preparation of flame retardant component, the temperature is heated to 50°C and stirred for 8 hours.

[0157] Example 9

[0158] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (1) the preparation of the flame retardant component, the temperature is raised to 130°C and stirred for 3 hours.

[0159] Example 10

[0160] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (2) the preparation of the polymerized MDI composition, high-functionality polymerized MDI was not used, but PM-400 of equal mass was used instead.

[0161] Example 11

[0162] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (2) preparation of the polymeric MDI composition, 1.6 kg PM-130, 1.4 kg high-functionality polymeric MDI (the average functionality of the two is 2.80) and 1 kg flame retardant component are used so that the overall NCO content of the polymeric MDI composition is similar to that in Example 1.

[0163] Example 12

[0164] The preparation method of the polyurethane rigid foam material in this embodiment is the same as that in Example 1. The main difference is that in step (2) the preparation of the polymeric MDI composition, 0.8 kg PM-700, 2.2 kg high-functionality polymeric MDI (the average functionality of the two is 2.96) and 1 kg flame retardant component are used so that the overall NCO content of the polymeric MDI composition is similar to that in Example 1.

[0165] Comparative Example 1

[0166] The preparation method of the polyurethane rigid foam material in this comparative example is the same as that in Example 1, the main difference being that steps (1) and (2) were not performed, and only PM-400 was used for component A.

[0167] Comparative Example 2

[0168] The preparation method of the polyurethane rigid foam material in this comparative example is the same as that in Example 1, the main difference being that steps (1) and (2) were not performed, and component A was only a mixture of 94wt% PM-400 and 6wt% triethyl phosphate.

[0169] Test case

[0170] (1) Tests of the properties of the polymeric MDI composition:

[0171] The viscosity and NCO content of polymeric MDI were tested according to GB / T 12009.3-2009 "Plastics - Polymethylene Polyphenyl Isocyanates - Part 3: Determination of Viscosity" and GB / T 12009.4-2016 "Plastics - Aromatic Isocyanates for Polyurethane Production - Part 4: Determination of Isocyanate Content".

[0172] The test results are shown in Table 1 below:

[0173] Table 1

[0174]

[0175] (2) Performance testing of rigid polyurethane foam materials:

[0176] The density, dimensional stability, limiting oxygen index, and compressive strength of the specimens were tested according to GB / T 6343-2009 "Determination of Apparent Density of Foamed Plastics and Rubber", GB / T 8811-2008 "Test Method for Dimensional Stability of Rigid Foamed Plastics", GB / T 2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method", and GB / T 8813-2020 "Determination of Compressive Properties of Rigid Foamed Plastics".

[0177] The test results are shown in Table 2 below.

[0178] Table 2

[0179]

[0180] As can be seen from the comparison between Examples 1-12 and Comparative Examples 1-2, the present application uses a blend of a first polymeric MDI with a specific level of functionality, a second polymeric MDI, and a flame-retardant component with a specific structure, which enables the prepared polyurethane rigid foam material to have both excellent flame-retardant properties and dimensional stability.

[0181] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0182] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A polymeric MDI composition, characterized in that, Includes polymeric MDI and flame-retardant components; The average functionality of the polymeric MDI is 2.7~3; The flame-retardant component includes an isocyanate polymer with an active structure and a liquid flame retardant, wherein the active structure includes one or more of an aromatic imide ring, an oxazolidinone ring, and an isocyanurate ring.

2. The polymeric MDI composition according to claim 1, characterized in that, By weight percentage, including: The polymeric MDI is 75%~90%. The flame retardant component is 10%~25%.

3. The polymeric MDI composition according to claim 1, characterized in that, The polymeric MDI comprises: The first polymeric MDI has a functionality of <2.9; The second polymerized MDI has a functionality of 2.9 to 3.

1.

4. The polymeric MDI composition according to claim 3, characterized in that, By weight percentage, including: The first polymeric MDI is 20%~40%. The second polymerized MDI is 35%~55%, and The flame retardant component is 10%~25%; The sum of the mass percentages of the first polymeric MDI and the second polymeric MDI is 75% to 90%.

5. The polymeric MDI composition according to claim 1, characterized in that, The flame-retardant component is prepared by mixing a diisocyanate monomer with a liquid flame retardant and carrying out a first polymerization reaction; or... The flame retardant component is prepared by mixing diisocyanate monomers, active compounds and liquid flame retardants to carry out a second polymerization reaction; the active compound includes one or two of aromatic anhydrides and epoxy resins.

6. The polymeric MDI composition according to claim 5, characterized in that, The flame-retardant component has one or more of the following characteristics: (1) The diisocyanate monomer includes one or more of aromatic diisocyanate monomers, aliphatic diisocyanate monomers and alicyclic diisocyanate monomers, and may optionally include one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isoflurone diisocyanate; (2) Based on the total mass of the flame retardant components, the amount of diisocyanate monomer added is 10% to 90%, and can be selected as 30% to 60%; (3) The aromatic anhydride includes one or more of phthalic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride and biphenyl tetracarboxylic dianhydride; (4) The amount of aromatic anhydride added is 0% to 50% based on the total mass of the flame retardant components, and can be selected as 0% to 30%; (5) The epoxy resin includes one or more of bisphenol A type epoxy resin, biphenyl type epoxy resin and DOPO type epoxy resin; (6) The amount of epoxy resin added is 0% to 40% based on the total mass of the flame retardant components, and can be selected as 0% to 20%; (7) The liquid flame retardant includes one or more of phosphorus-based flame retardants, chlorine-based flame retardants and bromine-based flame retardants, and optionally includes phosphorus-based flame retardants, and further optionally includes one or more of tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, dimethyl methyl phosphate, trimethyl phosphate, triethyl phosphate and triphenyl phosphate; (8) The amount of liquid flame retardant added is 10% to 90% based on the total mass of the flame retardant components, and can be selected as 10% to 40%; (9) The conditions for the first polymerization reaction and the second polymerization reaction each independently include: the reaction is carried out in the presence of a catalyst, and after the reaction is completed, an inhibitor is added; Optionally, the catalyst comprises one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, tris(dimethylaminopropyl)hexahydrotriazine, potassium isooctanoate, and potassium acetate; Optionally, the amount of catalyst added is 500ppm to 3000ppm, or optionally 1000ppm to 2000ppm, based on the mass of the diisocyanate monomer. Optionally, the polymerization inhibitor includes one or more of benzoyl chloride, benzenesulfonyl chloride, and p-toluenesulfonyl chloride; Optionally, the amount of the polymerization inhibitor added is 2000ppm to 4000ppm based on the mass of the diisocyanate monomer; Optionally, the reaction temperature is 50℃~130℃, or optionally 70℃~110℃; Optionally, the reaction time is 3h~8h, or 4h~6h.

7. The polymeric MDI composition according to claim 3, characterized in that, The second polymeric MDI has one or more of the following characteristics: (1) The NCO content is 31.5%~33%; (2) The viscosity at 25℃ is 90cP~140cP.

8. The polymeric MDI composition according to any one of claims 1 to 7, characterized in that, The polymeric MDI composition has one or more of the following characteristics: (1) The NCO content is 25%~31%, and 27%~30% can be selected; (2) The viscosity at 25℃ is 100cP~600cP, and can be selected as 200cP~400cP.

9. A rigid polyurethane foam material, characterized in that, The raw materials include polyisocyanate components, polyol components, and foaming agents; The polyisocyanate component includes the polymeric MDI composition according to any one of claims 1 to 8.

10. The rigid polyurethane foam material according to claim 9, characterized in that, The mass ratio of the polyisocyanate component, the polyol component and the foaming agent is (160~210):(80~130):(5~20).

11. The rigid polyurethane foam material according to claim 9 or 10, characterized in that, The foaming agent includes one or more of cyclopentane, isopentane, and n-pentane.

12. The method for preparing the rigid polyurethane foam material according to any one of claims 9 to 11, characterized in that, Includes the following steps: The polyisocyanate component, the polyol component, and the foaming agent are mixed and stirred to foam, thereby preparing the rigid polyurethane foam material. Optionally, the stirring and foaming conditions include: a rotation speed of 2000 r / min to 3000 r / min and a time of 3 s to 7 s.

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