A polyurethane foam material, its preparation method and application

Abstract

This invention relates to a polyurethane foam material, its preparation method, and its application. The method includes the following steps: (1) preparing a polyol solution with toluene, and then mixing the polyol solution with an aqueous solution of particulate material to obtain an emulsion; (2) adding isocyanate and a catalyst to the emulsion and stirring evenly to obtain a mixed system; (3) foaming the mixed system to obtain a polyurethane foam material. This invention overcomes the shortcomings of existing polyurethane foaming processes that require the use of surfactants (foam stabilizers) as emulsifiers, to stabilize foam and adjust cell size, and the difficulties in material stirring and dispersion caused by high solution viscosity. This invention provides a method for preparing a polyurethane foam material that is surfactant-free, has low solution viscosity, and is safe and efficient. The polyurethane foam prepared by this invention has excellent performance, small foam pore size, and a wide range of applications.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane foam material technology, and particularly relates to a polyurethane foam material, its preparation method and application. Background Technology

[0002] Polyurethane foam is produced by polymerization and foaming of polyols and polyisocyanates as the main raw materials, with the help of surfactants, foaming agents, catalysts, and other additives. The most commonly used polyols in the industrial production of polyurethane foam include polyester polyols, polyether polyols, vegetable oil polyols, and polymer polyols. Commonly used polyisocyanates include toluene diisocyanate (TDI), polymethylene polyphenyl isocyanate (PAPI), diphenylmethane diisocyanate (MDI), and liquefied MDI (L-MDI). Due to its excellent thermal insulation, heat insulation, shock absorption, and sound insulation properties, polyurethane foam has wide applications in construction, transportation, and daily necessities.

[0003] Traditional polyurethane foaming processes still present several challenges. First, to ensure uniform material dispersion, stabilize the foam, and obtain small, uniform pore sizes, surfactants are typically added during polyurethane foaming to reduce the interfacial tension of the mixture. Since pore size and uniformity are key factors determining the thermal insulation, shock absorption, and sound insulation properties of polyurethane foam, large amounts of surfactant are required to achieve smaller pore sizes. However, while reducing interfacial tension, large amounts of surfactant also lower the interfacial tension gradient, leading to pore merging and even collapse. This makes it difficult to obtain polyurethane foam materials with very small pore sizes; polyurethane foam materials prepared using existing technologies typically have pore sizes exceeding 100 micrometers. Second, the high viscosity of the system during traditional polyurethane foaming hinders material dispersion and increases energy consumption. Furthermore, in traditional pure water foaming systems, the reaction of isocyanate with water releases a large amount of heat, which can easily concentrate and cause core burning. This not only reduces foam quality but also poses a fire hazard.

[0004] Therefore, developing new foaming processes that are surfactant-free, low-viscosity, safe, and efficient has become a challenge for the further development of the polyurethane foam industry in recent years. Summary of the Invention

[0005] To address one or more technical problems existing in the prior art, this invention provides a polyurethane foam material, its preparation method, and its applications. This invention overcomes the shortcomings of existing polyurethane foaming processes, which require the use of surfactants (foam stabilizers) as emulsifiers to stabilize foam and adjust cell size, and the difficulties in material stirring and dispersion caused by high solution viscosity. This invention provides a method for preparing a surfactant-free, low-solution-viscosity, safe, and efficient polyurethane foam material. The polyurethane foam prepared by this invention exhibits excellent performance, small pore size, and a wide range of applications.

[0006] In a first aspect, the present invention provides a method for preparing a polyurethane foam material, the method comprising the following steps:

[0007] (1) Prepare a polyol solution by using toluene, and then mix the polyol solution with an aqueous solution of particulate material to obtain an emulsion;

[0008] (2) Add isocyanate and catalyst to the emulsion and stir until homogeneous to obtain a mixed system;

[0009] (3) The mixture system is foamed to obtain polyurethane foam material.

[0010] Preferably, the concentration of the polyol solution is 5-40 mg / mL, more preferably 5-20 mg / L, and even more preferably 10-20 mg / mL; the concentration of the aqueous solution of the particulate material is 0.1-10 mg / mL, more preferably 0.1-2 mg / mL, and even more preferably 1-2 mg / mL; and / or the volume ratio of the polyol solution to the aqueous solution of the particulate material is (1.5-4.5):1, more preferably (1.5-2.5):1, and even more preferably 2:1.

[0011] Preferably, in step (1), the method of uniform mixing is as follows: the polyol solution and the aqueous solution of particulate material are stirred at a speed of 50 to 600 r / min for 2 to 10 min.

[0012] Preferably, the raw materials for preparing the polyurethane foam material are, by volume, 80-120 parts of polyol solution, 25-60 parts of aqueous solution of particulate material, 3.5-7 parts of isocyanate and 0.8-1.5 parts of catalyst.

[0013] Preferably, in step (2), 0.01 to 0.3 parts of chain extender are added to the emulsion; preferably, the chain extender is one or more of 1,4-butanediol, 1,6-hexanediol, and glycerol.

[0014] Preferably, in step (2), the stirring is performed at a speed of 20-400 r / min for 2-15 min; and / or in step (3), the foaming is performed by first curing at room temperature for 1-10 h, and then maturing at 30-80°C for 2-72 h.

[0015] Preferably, the polyol is one or more of polyester polyol, polyether polyol, polysulfide polyol, polyacetal polyol, polycarbonate polyol, and vegetable oil polyol; the particulate material contained in the aqueous solution of the particulate material is inorganic material particles or modified inorganic material particles. Preferably, the particulate material contained in the aqueous solution of the particulate material is silica, calcium carbonate, talc, mica, kaolin, single-walled carbon nanotubes, multi-walled carbon nanotubes, single-layer graphene, multi-layer graphene, single-layer Mxene, multi-layer Mxene, carbon fiber, cellulose nanocrystals, cellulose nanofibers, lignin, bacterial cellulose, metal-organic framework materials, carbon quantum dots, gold particles, silver particles, palladium particles, iron oxide particles, platinum particles, glass particles, and thin-layer disulfide. The catalyst is one or more of molybdenum, few-layer molybdenum disulfide, carboxylated silica, carboxylated carbon nanotubes, carboxylated carbon quantum dots, carboxylated graphene, and carboxylated calcium carbonate; the isocyanate is one or more of 2,4-toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide-modified diphenylmethane diisocyanate; and / or the catalyst is one or more of metal catalysts, amine catalysts, amines with amidine groups and their derivatives, preferably, the catalyst is one or more of 1,5,7-triazidobicyclo(4.4.0)dec-5-ene, stannous octoate, 1,8-diazabicyclo[5.4.0]undec-7-ene, and 1,5-diazabicyclo(4.3.0)non-5-ene.

[0016] Preferably, the polyol is a polyester polyol, wherein the weight-average molecular weight of the polyester polyol is 100-52000 and the hydroxyl value is 200-750 mg KOH / g.

[0017] The present invention provides, in a second aspect, a polyurethane foam material prepared by the preparation method described in the first aspect of the present invention.

[0018] In a third aspect, the present invention provides the application of polyurethane foam materials prepared by the preparation method described in the first aspect of the present invention in terms of thermal insulation, heat insulation, sound absorption, noise reduction or sound insulation.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] (1) This invention provides a method for preparing a rigid polyurethane foam material that is surfactant-free, has low solution viscosity, and is safe and efficient. The method involves first preparing an emulsion from a polyol solution and an aqueous solution of particulate material, then adding isocyanate, a catalyst, etc., to the emulsion to obtain a mixed system. Under the action of the catalyst and inorganic material particles, the isocyanate and polyol react to form a gel, which is then dried to obtain the polyurethane foam material. In the reaction system of this invention, the particulate material and polyol are bonded at the interface through hydrogen bonding, electrostatic interactions, etc., which can reduce the interfacial tension between oil and water while avoiding pore formation and collapse caused by excessively low interfacial tension, thereby significantly reducing the pore size of the obtained rigid polyurethane foam material. The pore size of the rigid polyurethane foam material in this invention is only 5–25 μm, and the structure of the rigid polyurethane foam material in this invention differs from that of traditional foam materials. The rigid polyurethane foam material in this invention consists of many hollow spheres and / or irregular spheres spliced ​​together, with cavities between the spheres and / or irregular spheres. The rigid polyurethane foam material prepared by this invention has excellent sound absorption, noise reduction and sound insulation effects for high-frequency noise, and is particularly suitable as a sound absorption, noise reduction and sound insulation material.

[0021] (2) In some preferred embodiments of the present invention, by reasonably controlling the ratio of polyol, particulate material, isocyanate and catalyst, the polyurethane foam material can be effectively guaranteed to have low thermal conductivity, excellent heat insulation performance, low density, and high compressive strength, elongation and tear strength, which is more conducive to preparing rigid polyurethane foam material with smaller average foam pore size, larger specific surface area and greater sound absorption coefficient.

[0022] (3) In the process of preparing rigid polyurethane foam, the present invention does not require the use of surfactants, and the foaming process is more economical and environmentally friendly.

[0023] (4) In the process of preparing rigid polyurethane foam, the present invention uses an emulsion system, which makes it easy to disperse heat, improves the shortcomings of pure water foaming, reduces fire hazards, and makes the foaming process safer.

[0024] (5) In the process of preparing rigid polyurethane foam material, the viscosity of the system solution is lower, which reduces the energy consumption required for dispersion of stirring materials and the requirements for stirring equipment, and the energy consumption of the foaming process is low. Attached Figure Description

[0025] Figure 1 These are microstructure images (scanning electron microscope images) of the polyurethane foam material prepared in Example 2 of the present invention; wherein, (a) and (b) represent images of the polyurethane foam material prepared in Example 2 at different magnifications.

[0026] Figure 2These are microstructure images (scanning electron microscope images) of the polyurethane foam material prepared in Example 3 of the present invention; wherein, (a) and (b) represent images of the polyurethane foam material prepared in Example 3 at different magnifications. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] In a first aspect, the present invention provides a method for preparing a polyurethane foam material, the method comprising the following steps:

[0029] (1) Prepare a polyol solution (also called polyol toluene solution) with toluene, and then mix the polyol solution with the aqueous solution of particulate material to obtain an emulsion; specifically, for example, add the polyol solution and the aqueous solution of particulate material to a reactor and stir at a speed of 50-600 r / min for 2-10 min to mix evenly to obtain an emulsion;

[0030] (2) Add isocyanate and catalyst to the emulsion and stir evenly to obtain a mixed system; specifically, for example, add isocyanate and catalyst according to the formula under stirring conditions of 20-400 r / min and stir for 2-15 min to obtain a mixed system; in step (2), optionally, chain extender may also be added.

[0031] (3) The mixture is foamed to obtain a polyurethane foam material (also referred to as rigid polyurethane foam material); specifically, for example, the mixture is injected into a mold for foaming, wherein the foaming is: firstly, it is cured at room temperature (e.g., room temperature 15-35℃) for 1-10 hours, and then heated to 30-80℃ for 2-72 hours to obtain a rigid polyurethane foam material with small foam pore size and large specific surface area; the polyurethane foam material obtained by the present invention has a pore size of only 5-25 μm, and the rigid polyurethane foam material of the present invention has a different structure from traditional foam materials. The rigid polyurethane foam material of the present invention is composed of many hollow spheres and / or irregular spheres spliced ​​together, and the spheres and / or irregular spheres also have cavities between each other, for example, such as Figure 1 and Figure 2As shown. The method of the present invention does not require the use of surfactants (foam stabilizers) during the foaming process, and the viscosity of the foaming system solution is low. The method involves reacting a polyol toluene solution with an aqueous solution of particulate material to form an emulsion, and then adding isocyanate, catalyst, etc. to the emulsion to obtain a mixed system. Under the action of the catalyst, inorganic material particles, etc., the isocyanate and polyol react to form a gel in the mixed system, and after drying, the polyurethane foam material is obtained. The reaction system of the present invention first uses a polyol toluene solution and an aqueous solution of particulate material to form an emulsion, which not only reduces the viscosity of the foaming system solution, but more importantly, it enables the particulate particles (e.g., nanoparticles or micron-sized particles) to combine with the polyol at the interface through hydrogen bonding, electrostatic interactions, etc. The particulate particles are stably adsorbed at the oil-water interface, which can reduce the interfacial tension of oil and water while avoiding the formation and collapse of pores caused by excessively low interfacial tension, thereby significantly reducing the cell size of the obtained rigid polyurethane foam material. The rigid polyurethane foam material of this invention has a pore size of only 5-25 μm, preferably 10-25 μm. Furthermore, the rigid polyurethane foam material of this invention differs in structure from traditional foam materials. It consists of many hollow spheres and / or irregular spheres joined together, with cavities between them. The rigid polyurethane foam material obtained by this invention exhibits excellent sound absorption and noise reduction effects against high-frequency noise, achieving a sound absorption coefficient of 0.94-0.97 at high frequencies. In contrast, the average pore size of polyurethane foam materials in the prior art is typically as high as 100-200 μm, and the sound absorption coefficient at high frequencies is usually no greater than 0.90. The polyurethane foam material obtained by this invention is particularly suitable as a sound absorption, noise reduction, and sound insulation material. More importantly, the method of this invention can obtain a foam material with uniform pore size without the need for separate addition of a foam stabilizer.

[0032] According to some preferred embodiments, the concentration of the polyol solution is 5–40 mg / mL (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, or 40 mg / mL), preferably 5–20 mg / L, more preferably 10–20 mg / mL; the concentration of the aqueous solution of the particulate material is 0.1–10 mg / mL (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, ... The concentration of the polyol solution is 1.7, 1.8, 1.9, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mg / mL, preferably 0.1 to 2 mg / mL, more preferably 1 to 2 mg / mL; and / or the volume ratio of the polyol solution to the aqueous solution of the particulate material is (1.5 to 4.5):1 (e.g. 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1), preferably (1.5 to 2.5):1, more preferably 2:1.

[0033] In this invention, the concentration of the polyol solution is preferably 5-40 mg / mL, the concentration of the aqueous solution of the particulate material is preferably 0.1-10 mg / mL, and the volume ratio of the polyol solution to the aqueous solution of the particulate material is (1.5-4.5):1. This is beneficial to the formation of the emulsion, and the emulsion formed under these conditions is more favorable to the foaming system. While ensuring the compressive strength, elongation, tear strength and other properties of the material, it is also beneficial to prepare a rigid polyurethane foam material with a smaller average foam pore size, a larger specific surface area and a larger high-frequency noise absorption coefficient.

[0034] According to some preferred embodiments, in step (1), the mixing is carried out by stirring the polyol solution and the aqueous solution of the particulate material at a speed of 50 to 600 r / min (e.g., 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 or 600 r / min) for 2 to 10 minutes (e.g., 2, 3, 4, 5, 6, 7, 8, 9 or 10 minutes).

[0035] According to some preferred embodiments, the raw materials for preparing the polyurethane foam material are, by volume parts: 80-120 parts of polyol solution (e.g., 80, 85, 90, 95, 100, 105, 110, 115 or 120 parts), 25-60 parts of aqueous solution of particulate material (e.g., 25, 30, 35, 40, 45, 50, 55 or 60 parts), 3.5-7 parts of isocyanate (e.g., 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7 parts), and 0.8-1.5 parts of catalyst (e.g., 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4 or 1.5 parts).

[0036] In this invention, it is preferable to rationally control the ratio of polyol, particulate material, isocyanate and catalyst, which can effectively ensure that the prepared polyurethane foam material has low thermal conductivity, excellent thermal insulation performance, low density, and high compressive strength, elongation and tear strength without the need to add surfactant separately to stabilize the foam. It is also beneficial to prepare rigid polyurethane foam material with smaller average foam pore size, larger specific surface area and greater high-frequency noise absorption coefficient.

[0037] According to some preferred embodiments, in step (2), 0.01 to 0.3 parts (e.g., 0.01, 0.05, 0.1, 0.15, 0.2, 0.25 or 0.3 parts) of chain extender may be added to the emulsion; in this invention, "parts" refers to "volume parts", and in specific embodiments and comparative examples, the unit of volume parts can be uniformly "mL" or "L" or other volume units; preferably, the chain extender is one or more of 1,4-butanediol, 1,6-hexanediol, and glycerol.

[0038] According to some preferred embodiments, in step (2), the stirring is performed at a speed of 20–400 r / min (e.g., 20, 50, 80, 100, 150, 200, 250, 300, 350 or 400 r / min) for 2–15 min (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 min); and / or in step (3), the foaming is performed by first curing at room temperature (e.g., room temperature 15–35°C) for 1–10 h. (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10h), and then cured at 30-80℃ (e.g. 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃) for 2-72h (e.g. 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68 or 72h); more preferably, the foaming is: first cured at room temperature for 4-8h, and then cured at 50-80℃ for 18-36h.

[0039] According to some preferred embodiments, the polyol is one or more of polyhydroxy polymers such as polyester polyol, polyether polyol, polysulfide polyol, polyacetal polyol, polycarbonate polyol, vegetable oil polyol, and polymer polyol; the particulate material contained in the aqueous solution of the particulate material is inorganic material particles or modified inorganic material particles. Preferably, the particulate material contained in the aqueous solution of the particulate material is silica, calcium carbonate, talc, mica, kaolin, single-walled carbon nanotubes, multi-walled carbon nanotubes, single-layer graphene, or multi-layer graphene. The material comprises one or more of the following: single-layer Mxene, multi-layer Mxene, carbon fiber, cellulose nanocrystals, cellulose nanofibers, lignin, bacterial cellulose, metal-organic framework materials, carbon quantum dots, gold particles, silver particles, palladium particles, iron oxide particles, platinum particles, glass particles, thin-layer molybdenum disulfide, few-layer molybdenum disulfide, carboxylated silicon dioxide, carboxylated carbon nanotubes, carboxylated carbon quantum dots, carboxylated graphene, and carboxylated calcium carbonate; preferably, the particulate material contained in the aqueous solution of the particulate material is carboxylated silicon dioxide or cellulose nanocrystals; the present invention does not specifically limit the source of carboxylated silicon dioxide or cellulose nanocrystals, for example, commercially available products or products synthesized by existing methods can be used. Taking carboxylated silicon dioxide as an example, in some specific embodiments, the carboxylated silicon dioxide can be, for example, a carboxylated silicon dioxide product with an average diameter of 20nm, brand name microspheres-nanospheres, and product number 140506-10; in the present invention, the shape of the inorganic material particles can be, for example, granules, The inorganic material particles can be rod-shaped or sheet-shaped, and the particle size of the inorganic material particles can be, for example, 10 nm to 500 μm; and / or the isocyanate is one or more of 2,4-toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate (PAPI), and carbodiimide-modified diphenylmethane diisocyanate. Preferably, the isocyanate is 2,4-toluene diisocyanate TDI or diphenylmethane diisocyanate MDI (also known as 4,4'-diphenylmethane diisocyanate).

[0040] According to some preferred embodiments, the catalyst may specifically include the following substances: amine catalysts commonly used in the preparation of polyurethane foam, metal catalysts, amines with amidine groups and their derivatives, or any combination of the above catalysts; for metal catalysts, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, and other tin-based catalysts used in polyurethane foaming are preferred. For amine catalysts, triethylenediamine, trimethylaminoethylethanolamine, dimethylethyl ethylethanolamine, dimethylaminomorpholine, triethylamine, 1-isobutyl-2-methylimidazolium, methylmorpholine, ethylmorpholine, diethanolamine, tetramethylhexamethylenediamine, dimethylcyclohexylamine, tetramethylpropylenediamine, trimethylaminoethylpiperazine, tetramethylethylenediamine, N,N-dimethylbenzylamine, dimethylaminoethoxyethanol, dimethylaminohexanol, methylhydroxypiperazine, etc. can also be used; in addition, amines with amidine groups and their derivatives can also be used, preferably 1,5,7-triazidobicyclo(4.4.0)dec-5-ene (TBD), 1,8-diazabicyclo[5.4.] [0] Undec-7-ene (DBU), 1,5-diazabicyclo(4.3.0)non-5-ene (DBN), 6-dibutylamino-1,8-diazabicyclo[5.4.0]-7-undecene, etc.; In addition, the catalyst can also be a weak acid alkali metal salt, a trimer catalyst, etc., preferably, the catalyst is one or more of 1,5,7-triazidobicyclo(4.4.0)dec-5-ene (TBD), stannous octoate, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo(4.3.0)non-5-ene (DBN); more preferably, the catalyst is stannous octoate.

[0041] This invention does not specifically limit the substances such as polyols, particulate materials, isocyanates, and catalysts mentioned above. For example, commercially available products or products synthesized by existing methods can be used.

[0042] According to some preferred embodiments, the polyol is a polyester polyol, the weight-average molecular weight of which is 100-52000 and the hydroxyl value is 200-750 mg KOH / g.

[0043] According to some preferred embodiments, other additives commonly used in the polyurethane foaming industry can also be used in this invention as needed, including antioxidants, ultraviolet absorbers, flame retardants, antibacterial agents, luminescent agents, conductive agents, insulating agents, colorants, fragrances, and light stabilizers. Specifically, for example, to improve the anti-aging properties of polyurethane foam materials, antioxidants, ultraviolet absorbers, or light stabilizers can be used in conjunction during the foaming process. Specifically, antioxidants include phenolic antioxidants, secondary aromatic amines, and phosphorus-based antioxidants, etc., and ultraviolet absorbers include o-hydroxybenzophenone-based, benzotriazole-based, hindered amine-based, and phenol-based, etc. The light stabilizer is preferably a hindered amine-based light stabilizer, specifically, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, etc.

[0044] The present invention provides, in a second aspect, a polyurethane foam material prepared by the preparation method described in the first aspect of the present invention.

[0045] In a third aspect, the present invention provides the application of polyurethane foam materials prepared by the preparation method described in the first aspect of the present invention in terms of thermal insulation, heat insulation, sound absorption, noise reduction or sound insulation.

[0046] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments. The present invention may have many other embodiments, and those skilled in the art can make various corresponding changes and modifications based on the present invention without departing from its spirit and essence; however, all such corresponding changes and modifications should fall within the scope of protection of the appended claims.

[0047] Example 1

[0048] ① Prepare a polyester polyol solution with a concentration of 20 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 1 mg / mL using water. Mix 100 mL of polyester polyol solution and 50 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0049] ② Add 3.5 mL of diphenylmethane diisocyanate (MDI) and 1.2 mL of stannous octoate to the emulsion and continue stirring at 200 r / min for 5 min until homogeneous to obtain a mixed system.

[0050] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, cure at room temperature (25°C) for 5 hours, and then heat to 60°C for 24 hours.

[0051] Example 2

[0052] ① Prepare a polyester polyol solution with a concentration of 20 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 1 mg / mL using water. Mix 100 mL of polyester polyol solution and 50 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0053] ② Add 7 mL of diphenylmethane diisocyanate (MDI) and 1.2 mL of stannous octoate to the emulsion and continue stirring at 200 r / min for 5 min until homogeneous to obtain a mixed system.

[0054] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, cure at room temperature (25°C) for 5 hours, and then heat to 60°C for 24 hours.

[0055] The microstructure (SEM image) of the polyurethane foam material prepared in this embodiment is shown below. Figure 1 As shown; from Figure 1 As can be seen, the polyurethane foam material prepared in this embodiment is composed of multiple irregular hollow structures with openings spliced ​​together.

[0056] Example 3

[0057] ① Prepare a polyester polyol solution with a concentration of 20 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 1 mg / mL using water. Mix 100 mL of polyester polyol solution and 50 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0058] ② Add 3.5 mL of diphenylmethane diisocyanate (MDI), 1.2 mL of stannous octoate, and 0.2 mL of chain extender glycerol to the emulsion and continue stirring at 200 r / min for 5 min until homogeneous to obtain a mixed system.

[0059] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, cure at room temperature (25°C) for 5 hours, and then heat to 60°C for 24 hours.

[0060] The microstructure (SEM image) of the polyurethane foam material prepared in this embodiment is shown below. Figure 2 As shown; from Figure 2 As can be seen, the polyurethane foam material prepared in this embodiment is composed of multiple closed hollow spheres interconnected to form the foam material. From Figure 1 and Figure 2It is known that the polyurethane foam material obtained by the present invention has a foam structure different from that of traditional polyurethane foam materials. The polyurethane foam material obtained by the present invention has cavities both inside and outside the sphere. More importantly, as a system without the addition of foam stabilizers, the foam pore size obtained by the present invention is smaller and more uniform.

[0061] Example 4

[0062] ① Prepare a polyester polyol solution with a concentration of 20 mg / mL using toluene, and prepare an aqueous solution of cellulose nanocrystals with a concentration of 1 mg / mL using water. Mix 100 mL of polyester polyol solution and 50 mL of cellulose nanocrystal aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0063] ② Add 7 mL of diphenylmethane diisocyanate (MDI) and 1.2 mL of stannous octoate to the emulsion and continue stirring at 200 r / min for 5 min until homogeneous to obtain a mixed system.

[0064] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, cure at room temperature (25°C) for 5 hours, and then heat to 60°C for 24 hours.

[0065] Example 5

[0066] Example 5 is basically the same as Example 2, except that:

[0067] ① Prepare a polyester polyol solution with a concentration of 5 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 0.3 mg / mL using water. Mix 90 mL of polyester polyol solution and 60 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0068] ② Add 3.5 mL of diphenylmethane diisocyanate (MDI) and 1.2 mL of stannous octoate to the emulsion and continue stirring at 200 r / min for 5 min until homogeneous to obtain a mixed system.

[0069] Example 6

[0070] Example 6 is basically the same as Example 2, except that:

[0071] ① Prepare a polyester polyol solution with a concentration of 40 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 10 mg / mL using water. Mix 120 mL of polyester polyol solution and 30 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain an emulsion.

[0072] Example 7

[0073] Example 7 is basically the same as Example 2, except that:

[0074] ① Prepare a polyester polyol solution with a concentration of 4 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 2 mg / mL using water. Mix 80 mL of polyester polyol solution and 80 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain a mixed solution.

[0075] ② Add 3.5 mL of diphenylmethane diisocyanate (MDI) and 1.2 mL of stannous octoate to the mixed solution and continue stirring at 200 r / min for 5 min until homogeneous to obtain the mixed system.

[0076] Example 8

[0077] Example 8 is basically the same as Example 2, except that:

[0078] ① Prepare a polyester polyol solution with a concentration of 50 mg / mL using toluene, and prepare a carboxylated silica aqueous solution with a concentration of 1 mg / mL using water. Mix 150 mL of polyester polyol solution and 30 mL of carboxylated silica aqueous solution at a speed of 200 r / min for 5 min to obtain a mixed solution. Use this mixed solution to replace the emulsion in Example 2 for subsequent steps ② and ③.

[0079] Comparative Example 1

[0080] ① Mix 80g of polyester polyol PS-3152, 2g of foam stabilizer (silicone oil AK-8803), 1g of stannous octoate and 1g of carboxylated silica at a speed of 1000r / min for 5min to obtain component A.

[0081] ② Add 45g of component B diphenylmethane diisocyanate (MDI) and 2g of water to component A, and continue stirring at 1000r / min for 10s until homogeneous to obtain a mixed system.

[0082] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, foam at 40°C for 5 minutes, and then cure at room temperature (25°C) for 24 hours.

[0083] Comparative Example 2

[0084] ① Mix 80g of polyester polyol PS-3152, 2g of foam stabilizer (silicone oil AK-8803) and 1g of stannous octoate at a speed of 1000r / min for 5min until homogeneous to obtain component A.

[0085] ② Add 45g of component B diphenylmethane diisocyanate (MDI) and 2g of water to component A, and continue stirring at 1000r / min for 10s until homogeneous to obtain a mixed system.

[0086] ③ Pour the mixture into a mold for foaming to obtain polyurethane foam material; the foaming process is as follows: first, foam at 40°C for 5 minutes, and then cure at room temperature (25°C) for 24 hours.

[0087] The performance of the polyurethane foam materials finally obtained in each embodiment and comparative example was tested, and the results are shown in Table 1.

[0088] Table 1

[0089]

[0090] In Table 1, the symbol "-" indicates that the performance metric was not tested.

[0091] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a polyurethane foam material, characterized in that, The method includes the following steps: (1) Prepare a polyol solution with toluene, and then mix the polyol solution with an aqueous solution of particulate material to obtain an emulsion; the concentration of the polyol solution is 5-40 mg / mL, the concentration of the aqueous solution of particulate material is 0.1-10 mg / mL, and the volume ratio of the polyol solution to the aqueous solution of particulate material is (1.5-4.5):

1. (2) Add isocyanate and catalyst to the emulsion and stir until homogeneous to obtain a mixed system; (3) The mixture is foamed to obtain polyurethane foam material; The raw materials for preparing the polyurethane foam material are, by volume parts: The mixture contains 80–120 parts of polyol solution, 25–60 parts of aqueous solution of particulate material, 3.5–7 parts of isocyanate, and 0.8–1.5 parts of catalyst. The polyurethane foam material has a pore size of 5-25 μm and has excellent sound absorption and noise reduction effect on high-frequency noise, with a sound absorption coefficient of 0.94-0.97 at high frequencies.

2. The preparation method according to claim 1, characterized in that: The concentration of the polyol solution is 5–20 mg / L; The concentration of the aqueous solution of the particulate material is 0.1–2 mg / mL; and / or The volume ratio of the polyol solution to the aqueous solution of the particulate material is (1.5-2.5):

1.

3. The preparation method according to claim 2, characterized in that: The concentration of the polyol solution is 10–20 mg / mL; The concentration of the aqueous solution of the particulate material is 1–2 mg / mL; and / or The volume ratio of the polyol solution to the aqueous solution of the particulate material is 2:

1.

4. The preparation method according to claim 1, characterized in that: In step (1), the method of uniform mixing is as follows: the polyol solution and the aqueous solution of particulate material are stirred at a speed of 50-600 r / min for 2-10 min.

5. The preparation method according to claim 1, characterized in that: In step (2), 0.01 to 0.3 parts of chain extender are added to the emulsion.

6. The preparation method according to claim 5, characterized in that: The chain extender is one or more of 1,4-butanediol, 1,6-hexanediol, and glycerol.

7. The preparation method according to claim 1, characterized in that: In step (2), the stirring is performed at a speed of 20–400 r / min for 2–15 min; and / or In step (3), the foaming process involves first curing at room temperature for 1 to 10 hours, and then aging at 30 to 80°C for 2 to 72 hours.

8. The preparation method according to claim 1, characterized in that: The polyol is one or more of polyester polyol, polyether polyol, polysulfide polyol, polyacetal polyol, and vegetable oil polyol. The particulate material in the aqueous solution is an inorganic material or a modified inorganic material. The isocyanate is one or more of 2,4-toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide-modified diphenylmethane diisocyanate; and / or The catalyst is one or more of the following: metal catalyst, amine catalyst, amine with an amidine group and its derivatives.

9. The preparation method according to claim 8, characterized in that: The particulate material in the aqueous solution contains one or more of the following: silica, calcium carbonate, talc, mica, kaolin, single-walled carbon nanotubes, multi-walled carbon nanotubes, single-layer graphene, multi-layer graphene, single-layer Mxene, multi-layer Mxene, carbon fiber, cellulose nanocrystals, cellulose nanofibers, lignin, bacterial cellulose, metal-organic framework materials, carbon quantum dots, gold particles, silver particles, palladium particles, iron oxide particles, platinum particles, glass particles, thin-layer molybdenum disulfide, carboxylated silica, carboxylated carbon nanotubes, carboxylated carbon quantum dots, carboxylated graphene, and carboxylated calcium carbonate.

10. The preparation method according to claim 8, characterized in that: The catalyst is one or more of 1,5,7-triazidobicyclo(4.4.0)dec-5-ene, stannous octoate, 1,8-diazabicyclo[5.4.0]undec-7-ene, and 1,5-diazabicyclo(4.3.0)non-5-ene.

11. The preparation method according to claim 8, characterized in that: The polyol is a polyester polyol with a weight-average molecular weight of 100-52000 and a hydroxyl value of 200-750 mg KOH / g.

12. A polyurethane foam material prepared by any one of claims 1 to 11.

13. The use of polyurethane foam materials prepared by any one of claims 1 to 11 in terms of thermal insulation, heat insulation, sound absorption, noise reduction or sound insulation.

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