A polyurethane foam material having a wide frequency range sound absorption

Abstract

The present application provides a kind of polyurethane foam of wide frequency range sound absorption.The polyurethane foam of wide frequency range sound absorption includes polyurethane matrix and the porous polyurethane microsphere of bimodal distribution of particle size dispersed therein, the porous polyurethane microsphere is prepared by incomplete reverse emulsification method, its particle size presents bimodal distribution, the particle size ratio of large particle size porous microsphere and small particle size porous microsphere is 2:1~10:1, and the total mass ratio of large particle size porous microsphere and small particle size porous microsphere is 0.5:1~4:1.The present application is dispersed by bimodal distribution of porous polyurethane microsphere in polyurethane foam material, so as to obtain the polyurethane foam sound absorption material of wide frequency range, and the method process is simple.

Description

Technical Field

[0001] This invention belongs to the technical field of sound-absorbing and noise-reducing materials, specifically relating to a wide-frequency-range sound-absorbing polyurethane foam material. Background Technology

[0002] With the development of science and technology and modern industry, noise pollution has become a global problem. At the same time, with increasing environmental awareness, people have higher and higher requirements for the sound environment. A comprehensive report published by the WHO and the EU Collaborative Research Centre, "The Burden of Disease Due to Noise Pollution," points out that even when people are asleep, noise pollution can raise blood pressure. Furthermore, noise affects the nervous system, causing irritability, decreased vision, and impacting children's intellectual development. Moreover, the higher the population density and economic development of large and medium-sized cities, the higher the level of noise pollution. The use of porous sound-absorbing materials as a major method of sound absorption and noise reduction is increasingly being applied in practical life, among which porous foam materials, represented by polymer porous materials, are widely used.

[0003] Polyurethane foam is a commonly used sound-absorbing material with advantages such as low cost, simple processing, adjustable performance, and stable sound absorption. However, polyurethane foam usually has poor sound absorption performance at low frequencies (below 500Hz). Improving low-frequency sound absorption performance usually requires increasing the thickness of the material or leaving a cavity behind the material, which often means increasing the effective space occupied by the material.

[0004] In the prior art, Chinese patent CN105482436A discloses a biomass power plant ash-based polyurethane sound-absorbing and noise-reducing material, which mainly adds expanded perlite and rice husk ash to improve the mid-to-low frequency sound absorption performance of polyurethane foam. Chinese patent CN112724360A discloses a porous inorganic particle-modified polyurethane foam material with good sound absorption performance. However, the addition of expanded perlite and porous CaCO3 to polyurethane foam results in poor compatibility and a tendency for agglomeration or delamination.

[0005] Therefore, how to solve the above-mentioned defects of polyurethane foam materials is a major challenge facing this field. Summary of the Invention

[0006] The purpose of this invention is to provide a wide-frequency-range sound-absorbing polyurethane foam material, solve the problem of wide-frequency-range sound absorption, and prepare a polyurethane foam material with good sound absorption effect at high, medium and low frequencies.

[0007] To address the above technical problems, this invention provides porous polyurethane microspheres with a bimodal particle size distribution obtained by incomplete emulsification. By utilizing the low-frequency resonance of small-diameter porous microspheres and the mid-frequency resonance of large-diameter porous microspheres, along with the high-frequency sound absorption properties of polyurethane foam itself, a wide-frequency-range sound-absorbing polyurethane foam material can be prepared.

[0008] The present invention adopts the following technical solution:

[0009] A broadband sound-absorbing polyurethane foam material, wherein the foam material is prepared from component A and component B, wherein the mass ratio of component A to component B is 1:0.9 to 1:1.5, and the isocyanate index of the foam material is controlled at 0.8 to 3.0;

[0010] Component A comprises the following raw materials, in parts by mass:

[0011] Polyether polyol I, 55-80 parts, preferably 60-70 parts;

[0012] Polyurethane microspheres, 5-15 parts, preferably 5-10 parts;

[0013] Flame retardant, 0-20 parts, preferably 5-10 parts;

[0014] Chain extender, 0-8 parts, preferably 2-5 parts;

[0015] Foam stabilizer, 1-2 parts;

[0016] 0.5-1 part of pore-opening agent;

[0017] Catalyst I, 1.5-5 parts;

[0018] Water, 1-5 parts;

[0019] Component B is polyphenylmethane polyisocyanate.

[0020] In this invention, the emulsification temperature is first increased to reduce the strength of the interfacial film, resulting in incomplete polyurethane emulsification. The particle size of the polyurethane microspheres is then controlled by adjusting the concentration of hydrophilic ionic groups, thus obtaining porous polyurethane microspheres with a bimodal particle size distribution. Adding these bimodal porous polyurethane microspheres to the polyurethane foam provides, on the one hand, a propagation channel for sound waves to enter the material's interior due to the open-cell nature of the polyurethane foam and the porous microspheres. Simultaneously, high-frequency sound waves can accelerate the vibration velocity of air particles within the pores and speed up heat exchange between the air and the pore walls, thus giving the polyurethane foam material itself excellent high-frequency sound absorption properties. On the other hand, the porous polyurethane microspheres resonate with sound waves at certain frequencies. With the same density, smaller-diameter porous microspheres have smaller mass and therefore lower inertia. Under the same conditions, the inertia... Smaller microspheres are more sensitive to sound waves, with their resonant absorption peaks shifting to lower frequencies and narrowing. In contrast, the resonant frequency of larger porous microspheres is in the mid-frequency range. Furthermore, particle size also affects the volume of the microspheres; a smaller volume results in a correspondingly smaller moment of inertia. Under the same conditions, the rotational speed and angular velocity of the microspheres increase, inevitably leading to increased tangential contact forces between microspheres and between microspheres and the pore walls. This increased rotation and tangential force enhances the mutual slippage between microspheres, hindering synchronous motion and increasing frictional energy dissipation. Therefore, the resulting polyurethane foam material exhibits excellent sound absorption performance at high, mid, and low frequencies. In addition, compared to traditional inorganic fillers, polyurethane microspheres show better dispersibility and compatibility in polyurethane foam.

[0021] In this invention, the polyether polyol I in component A is selected from one or more of the following polyether polyols:

[0022] Polyether polyol 1, with sorbitol and / or sucrose-glycerol composite initiator as the initiator, propylene oxide as the polymerization unit, and hydroxyl value of 300-600 mgKOH / g, preferably one or more of Wanhua Chemical SYPG086, A490, R8336, and Tianjin Sanshi Chemical 450L;

[0023] Polyether polyol 2, with glycerol as the initiator, propylene oxide as the polymerization unit, and a hydroxyl value of 100-600 mgKOH / g, preferably one or more of Wanhua Chemical's A303, A305, A307 and A310;

[0024] Polyether polyol 3, a polyether polyol initiated with propylene glycol and polymerized with propylene oxide and / or a polyether polyol initiated with glycerol and polymerized with propylene oxide and ethylene oxide, having a hydroxyl value of 20-150 mgKOH / g, preferably one or more of Wanhua Chemical F3135, F3156, and A210.

[0025] In this invention, the polyether polyol I in component A comprises the following parts by mass of polyether polyol component:

[0026] Polyether polyol 1, added in a ratio of 0-20 parts, preferably 5-10 parts;

[0027] Polyether polyol 2 is added in a ratio of 5-25 parts, preferably 10-20 parts;

[0028] Polyether polyol 3 is added in a ratio of 40-60 parts, preferably 45-55 parts.

[0029] In this invention, the polyurethane microspheres are porous microspheres, preferably with a bimodal particle size distribution, comprising large-diameter microspheres and small-diameter microspheres; preferably, the particle size ratio of the large-diameter porous microspheres to the small-diameter porous microspheres is 2:1 to 10:1, more preferably 5:1 to 8:1, and the total mass ratio of the large-diameter porous microspheres to the small-diameter porous microspheres is 0.5:1 to 4:1, more preferably 1:1 to 2:1.

[0030] In this invention, the raw materials for the polyurethane microspheres are polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II.

[0031] In this invention, the polyether polyol II is the same as the polyether polyol I; preferably, in the polyether polyol II, the polyether polyol 1 is 0-15 parts, more preferably 5-10 parts; the polyether polyol 2 is 5-25 parts, more preferably 10-20 parts; and the polyether polyol 3 is 20-50 parts, more preferably 30-40 parts.

[0032] In this invention, the hydrophilic chain extender is one or more of 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, sodium 1,2-dihydroxy-3-propanesulfonate, sodium ethylenediamine ethanesulfonate, and N-methyldiethanolamine; preferably, the amount of hydrophilic chain extender added to the large-particle-size polyurethane microspheres is 1-2.5 parts, more preferably 1.5-2.5 parts; the amount of hydrophilic chain extender added to the small-particle-size polyurethane microspheres is 4-7 parts, more preferably 4-5 parts, by mass.

[0033] In this invention, the polyisocyanate is one or more of HDI, HMDI, TDI, MDI, PM200, PM400, and PM700.

[0034] In this invention, the catalyst is one or more of amines, organometallic catalysts, and metal salt catalysts, preferably one or more of triethanolamine, N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, triethylenediamine, bis(dimethylaminoethyl) ether, potassium acetate, organotin, and quaternary ammonium salts.

[0035] In this invention, the porous polyurethane microspheres are prepared using an incomplete reverse emulsification method; preferably, the preparation method includes the following steps:

[0036] S1: Polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II are placed in a diluent, heated and reacted to obtain polyurethane prepolymer A and the temperature is kept constant.

[0037] S2: Polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II are placed in a diluent, heated and reacted to obtain polyurethane prepolymer B and the temperature is kept constant.

[0038] S3: Water is continuously added to polyurethane prepolymer A under high-speed stirring, and stirring is continued. Then, polyurethane prepolymer B is added to the dispersion, and stirring is continued. After vacuum drying, polyurethane porous microspheres with bimodal particle size distribution are obtained.

[0039] In this invention, the reaction temperature of S1 and S2 is 40-100℃, the reaction time is 3-10h, and the constant temperature is 40-60℃, preferably 40-50℃.

[0040] In this invention, the amount of diluent added in S1 and S2 is 0.5-2.5 times the mass of the polyurethane microspheres. The diluent comprises one or more of N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, and acetone, preferably N,N-dimethylformamide and / or acetone.

[0041] In this invention, the stirring time for both S3 stages is 10-60 min.

[0042] In this invention, the amount of water added in step S3 is 2-4 times the mass of the polyurethane microspheres.

[0043] In this invention, the chain extender in component A is selected from one or more of glycerol, dipropylene glycol, diethylene glycol, and n-butanol.

[0044] In this invention, the flame retardant in component A is an alkyl phosphate ester, preferably one or more of tris(1-chloroethylpropyl) phosphate (TCPP), triethyl phosphate (TEP), dimethyl methyl phosphate (DMMP), and tris(2-chloroethyl) phosphate (TECP).

[0045] In this invention, the foam stabilizer in component A is selected from silicon-carbon bond non-hydrolyzable polysiloxane-polyether copolymers, preferably one or more of Momentive L-6164, L-5388 and L-580.

[0046] In this invention, the pore-opening agent in component A is one or more of Evonik O-501, Evonik O-500, and Mistex AK9905.

[0047] In this invention, catalyst I in component A is the same as catalyst II in polyurethane microspheres.

[0048] In this invention, the viscosity of component B, polyphenylmethane polyisocyanate, is 150-800 cp, preferably one or more of Wanhua Chemical PM200, PM400, PM700 and BASF M20S.

[0049] The high-open-porosity polyurethane cavity-filling foam can be prepared using methods known in the art, including but not limited to mechanical foaming and manual foaming. During the foaming process, the material temperature is controlled at 15-60℃, preferably 20-30℃; the mold temperature is 20-50℃, preferably 30-45℃; and the foaming and curing time is 0.5-4h, preferably 1-2h.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] (1) The problem of wide frequency range sound absorption has been solved. A polyurethane foam material with good sound absorption effect in high frequency, mid frequency and low frequency has been prepared. In the high frequency range of 2000-4000Hz, its sound absorption coefficient can reach up to 1.050. In the frequency range of 250-2000Hz, its sound absorption coefficient is above 0.4, and can reach up to 0.914. This shows that it has good sound absorption effect in the mid and low frequency range. In particular, even in the low frequency range below 500Hz, its sound absorption coefficient can still reach up to 0.756.

[0052] (2) Compared with traditional inorganic fillers, polyurethane microspheres have good dispersibility and compatibility in polyurethane foam. Detailed Implementation

[0053] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0054] The raw material information in the following examples and comparative examples is as follows:

[0055] Polyether polyols: Polyether polyol SYPG086, produced by Wanhua Chemical (Ningbo) Rongwei Polyurethane Co., Ltd., functionality 6, hydroxyl value 480mg KOH / g, molecular weight 700, industrial grade; Polyether polyol A310, produced by Wanhua Chemical (Ningbo) Rongwei Polyurethane Co., Ltd., functionality 3, hydroxyl value 168mg KOH / g, molecular weight 1000, industrial grade; Polyether polyol F3135, produced by Wanhua Chemical (Ningbo) Rongwei Polyurethane Co., Ltd., functionality 3, hydroxyl value 35mg KOH / g, molecular weight 4800, industrial grade; Polyether polyol A210, produced by Wanhua Chemical (Ningbo) Rongwei Polyurethane Co., Ltd., functionality 2, hydroxyl value 112mg KOH / g, molecular weight 1000, industrial grade; Chain extenders: Glycerin from Shenyang Shisan Biochemical Technology; Dipropylene glycol from Aladdin, purity 98%; Diethylene glycol from Hank Chemical. Hydrophilic chain extender: AAS, Quzhou Ruier Chemical Co., Ltd., 50% solids content, industrial grade; DHPA, Shenzhen Zike Biotechnology Co., Ltd.; Foam stabilizer: Momentive L-6164, L5388, L-510; Cell opener: Evonik O501, Mistex AK9905; Flame retardant: TCPP, TEP; Catalyst: Evonik pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, potassium acetate, Bi 8210, organic Bi, stannous octoate; Foaming agent: water; Polyisocyanate: Wanhua Chemical Polymer DMI, grades: PM200 (viscosity 150~250mPa·s), PM400 (viscosity 350~500mPa·s); Wanhua Chemical IPDI (viscosity 10mPa·s), MDI-100 (solid at room temperature).

[0056] The experimental instruments used in the following examples and comparative examples are as follows: circulating water vacuum pump (SHB-Ⅲ, Zhengzhou Huicheng Science and Industry Trade Co., Ltd.), rotary evaporator (RE52CS, Shanghai Yarong Biochemical Instrument Factory), and stirring sand mill dispersion multi-purpose machine (JSF-450, Shanghai Pushen Chemical Machinery Co., Ltd.).

[0057] In the following examples and comparative examples, the particle size of the polyurethane microspheres was measured using a dynamic light scattering instrument (instrument model: Zetasizer Nano ZS90, Malvern, UK). The sound absorption coefficient of the polyurethane foam material was measured using the standing wave tube method according to GBJ 88-1985 "Standard for Measurement of Sound Absorption Coefficient and Acoustic Impedance by Standing Wave Tube Method".

[0058] Examples 1-8

[0059] Preparation of porous polyurethane microspheres with bimodal particle size distribution:

[0060] A: According to the large-particle-size porous microsphere formulation in Table 1, polyether polyol II, polyisocyanate and catalyst II were placed in acetone as a diluent, heated to 58°C and refluxed for 5 hours, then kept constant at 50°C. A hydrophilic chain extender was added and reacted for 20 minutes to obtain polyurethane prepolymer A. The same operation was then performed according to the small-particle-size porous microsphere formulation in Table 1 to obtain polyurethane prepolymer B. 200g of water at 50°C was continuously added to polyurethane prepolymer A at 50°C and stirred at high speed for 20 minutes. Then, a fixed mass of polyurethane prepolymer B at 50°C was added and stirred for 20 minutes. After vacuum drying, polyurethane porous microspheres with a bimodal particle size distribution were obtained.

[0061] B: According to the large-particle-size porous microsphere formulation in Table 1, polyether polyol II, polyisocyanate and catalyst II were placed in acetone as a diluent, heated to 40°C and refluxed for 10 hours. The temperature was then kept constant at 40°C, and a hydrophilic chain extender was added and reacted for 20 minutes to obtain polyurethane prepolymer A. The same operation was then performed according to the small-particle-size porous microsphere formulation in Table 1 to obtain polyurethane prepolymer B. 300g of water at 40°C was continuously added to polyurethane prepolymer A at 40°C and stirred at high speed. After stirring for 40 minutes, a fixed mass of polyurethane prepolymer B at 40°C was added and stirred for 40 minutes. After vacuum drying, polyurethane porous microspheres with a bimodal particle size distribution were obtained.

[0062] C: According to the large-particle-size porous microsphere formulation in Table 1, polyether polyol II, polyisocyanate and catalyst II were placed in diluent N,N-dimethylformamide, heated to 100℃ and reacted for 3 hours, then kept at 60℃, and a hydrophilic chain extender was added and reacted for 20 minutes to obtain polyurethane prepolymer A; then, according to the small-particle-size porous microsphere formulation in Table 1, the same operation was performed to obtain polyurethane prepolymer B; 400g of water at 60℃ was continuously added to polyurethane prepolymer A at 60℃ and stirred at high speed for 20 minutes, then a fixed mass of polyurethane prepolymer B at 60℃ was added, stirred for 20 minutes, and after vacuum drying, polyurethane porous microspheres with bimodal particle size distribution were obtained.

[0063] Prepare the materials for each example according to the raw materials and dosages of the composition in Table 3, and foam them by hand to obtain the foam materials in Examples 1-8.

[0064] Manual foaming method: Control the material temperature to 25℃ before foaming, and mix for 8 seconds. Pour the mixed material into the mold, control the mold temperature to 40℃, and allow it to foam and cure for 2 hours.

[0065] Table 1. Formulation of porous polyurethane microspheres with bimodal particle size distribution (unit: g)

[0066]

[0067] The polyurethane microsphere formulations added in Comparative Examples 2-3 are the same as those in Examples 1-2.

[0068] Table 2. Particle size ratio and total mass ratio of bimodal porous polyurethane microspheres.

[0069]

[0070]

[0071] Table 3. Formulations of broadband sound-absorbing polyurethane foam materials in Examples 1-8 (unit: g)

[0072]

[0073] Comparative Examples 1-3

[0074] Table 4. Formulations of wideband sound-absorbing polyurethane foam materials in Comparative Examples 1-3

[0075]

[0076]

[0077] The foams prepared in Examples 1-8 and Comparative Examples 1-3 were subjected to standing wave tube sound absorption tests, and the results are shown in Table 5.

[0078] Table 5. Sound absorption coefficients of polyurethane foam materials prepared in Examples 1-8 and Comparative Examples 1-3 at different frequencies.

[0079] 125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz average Example 1 0.283 0.455 0.697 0.776 0.914 1.050 0.696 Example 2 0.291 0.458 0.714 0.759 0.843 0.921 0.664 Example 3 0.260 0.406 0.613 0.697 0.801 0.892 0.612 Example 4 0.209 0.354 0.645 0.687 0.766 0.879 0.590 Example 5 0.393 0.522 0.756 0.784 0.759 0.771 0.664 Example 6 0.313 0.472 0.688 0.808 0.801 0.833 0.653 Example 7 0.288 0.460 0.659 0.784 0.863 0.927 0.664 Example 8 0.359 0.511 0.737 0.752 0.698 0.646 0.617 Comparative Example 1 0.080 0.166 0.394 0.517 0.593 0.576 0.388 Comparative Example 2 0.114 0.193 0.440 0.697 0.878 0.782 0.517 Comparative Example 3 0.300 0.484 0.705 0.714 0.677 0.623 0.584

[0080] As can be seen from the test results in Table 5, compared with Comparative Example 1, the sound absorption coefficients of the polyurethane foams prepared in Examples 1-8 are all increased at different frequencies. At the same time, compared with Comparative Example 2 which only added large-particle-size porous polyurethane microspheres and Comparative Example 3 which only added small-particle-size porous polyurethane microspheres, the polyurethane foam material prepared in Example 1 has higher sound absorption coefficients in the high, medium and low frequency domains, and its average sound absorption coefficient is also higher.

[0081] The above shows that, compared with polyurethane foam prepared without porous polyurethane microspheres and polyurethane foam prepared with only monodisperse porous polyurethane microspheres, polyurethane foam prepared with porous polyurethane microspheres with bimodal particle size distribution has a wider frequency range of sound absorption capability and better overall sound absorption performance.

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A broadband sound-absorbing polyurethane foam material, characterized in that, The foam material is prepared from component A and component B, wherein the mass ratio of component A to component B is 1:0.9 to 1:1.

5. Component A comprises the following raw materials, in parts by mass: Polyether polyol I, 55-80 parts; Polyurethane microspheres, 5-15 parts; Flame retardant, 0-20 parts; Chain extender, 0-8 parts; Foam stabilizer, 1-2 parts; 0.5-1 part of pore-opening agent; Catalyst I, 1.5-5 parts; Water, 1-5 parts; The polyurethane microspheres are porous microspheres; The particle size of the polyurethane microspheres exhibits a bimodal distribution. Component B is polyphenylmethane polyisocyanate.

2. The foam material according to claim 1, characterized in that, Component A comprises the following raw materials, in parts by mass: Polyether polyol I, 60-70 parts; Polyurethane microspheres, 5-10 parts; Flame retardant, 5-10 parts; Chain extender, 2-5 parts.

3. The foam material according to claim 1, characterized in that, The polyether polyol I in component A is selected from one or more of the following polyether polyols: Polyether polyol 1, with sorbitol and / or sucrose-glycerol composite initiator as the initiator, propylene oxide as the polymerization unit, and hydroxyl value of 300-600 mgKOH / g; Polyether polyol 2, with glycerol as the initiator, propylene oxide as the polymerization unit, and a hydroxyl value of 100-600 mgKOH / g; Polyether polyol 3, polyether polyols initiated with propylene glycol and polymerized with propylene oxide and / or polyether polyols initiated with glycerol and polymerized with propylene oxide and ethylene oxide, with a hydroxyl value of 20-150 mgKOH / g.

4. The foam material according to claim 3, characterized in that, The polyether polyol I in component A is selected from one or more of the following polyether polyols: Polyether polyol 1 is one or more of Wanhua Chemical's SYPG086, A490, R8336, and Tianjin Sanshi Chemical's 450L; Polyether polyol 2 is one or more of Wanhua Chemical's A303, A305, A307, and A310; Polyether polyol 3 is one or more of Wanhua Chemical's F3135, F3156, and A210.

5. The foam material according to claim 3, characterized in that, The polyether polyol I in component A comprises the following parts by weight: Polyether polyol 1, added at a ratio of 0-20 parts; Polyether polyol 2, added in a ratio of 5-25 parts; Polyether polyol 3, added at a ratio of 40-60 parts.

6. The foam material according to claim 5, characterized in that, The polyether polyol I in component A comprises the following parts by weight: Polyether polyol 1, added at a ratio of 5-10 parts; Polyether polyol 2, added at a ratio of 10-20 parts; Polyether polyol 3, added at a ratio of 45-55 parts.

7. The foam material according to claim 1, characterized in that, The polyurethane microspheres include large-diameter microspheres and small-diameter microspheres.

8. The foam material according to claim 7, characterized in that, The particle size ratio of the large-diameter microspheres to the small-diameter microspheres is between 2:1 and 10:1, and the total mass ratio of the large-diameter microspheres to the small-diameter microspheres is between 0.5:1 and 4:

1.

9. The foam material according to claim 8, characterized in that, The particle size ratio of the large-diameter microspheres to the small-diameter microspheres is between 5:1 and 8:1, and the total mass ratio of the large-diameter microspheres to the small-diameter microspheres is between 1:1 and 2:

1.

10. The foam material according to claim 7, characterized in that, The raw materials for the polyurethane microspheres are polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II; And / or, the polyether polyol II is the same as the polyether polyol I; And / or, the hydrophilic chain extender is one or more of 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, sodium 1,2-dihydroxy-3-propanesulfonate, sodium ethylenediamine ethanesulfonate, and N-methyldiethanolamine; And / or, the polyisocyanate is one or more of HDI, HMDI, TDI, MDI, PM200, PM400, and PM700.

11. The foam material according to claim 10, characterized in that, In the polyether polyol II, by mass parts, polyether polyol 1 is 0-15 parts; polyether polyol 2 is 5-25 parts; and polyether polyol 3 is 20-50 parts. The amount of hydrophilic chain extender added to the large-diameter microspheres is 1-2.5 parts; the amount of hydrophilic chain extender added to the small-diameter microspheres is 4-7 parts, by mass.

12. The foam material according to claim 11, characterized in that, In the polyether polyol II, by mass parts, polyether polyol 1 is 5-10 parts; polyether polyol 2 is 10-20 parts; and polyether polyol 3 is 30-40 parts; The amount of hydrophilic chain extender added to the large-diameter microspheres is 1.5-2.5 parts; the amount of hydrophilic chain extender added to the small-diameter microspheres is 4-5 parts, by mass.

13. The foam material according to claim 1, characterized in that, The polyurethane microspheres were prepared using an incomplete reverse emulsification method.

14. The foam material according to claim 13, characterized in that, The incomplete reverse emulsification method includes the following steps: S1: Polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II are placed in a diluent, heated and reacted to obtain polyurethane prepolymer A and the temperature is kept constant. S2: Polyether polyol II, hydrophilic chain extender, polyisocyanate and catalyst II are placed in a diluent, heated and reacted to obtain polyurethane prepolymer B and the temperature is kept constant. S3: Water is continuously added to polyurethane prepolymer A while stirring at high speed. After stirring, polyurethane prepolymer B is added and stirring is continued. After vacuum drying, polyurethane microspheres with bimodal particle size distribution are obtained.

15. The foam material according to claim 14, characterized in that, The reaction temperature of S1 and S2 is 40-100℃, the reaction time is 3-10h, and the constant temperature is 40-60℃. And / or, the amount of diluent added in S1 and S2 is 0.5-2.5 times the raw material mass of the polyurethane microspheres.

16. The foam material according to claim 15, characterized in that, The constant temperature of S1 and S2 is 40-50℃.

17. The foam material according to claim 14, characterized in that, The stirring time for S3 is 10-60 min for both times; And / or, the amount of water added in S3 is 2-4 times the mass of the raw material of the polyurethane microspheres.

18. The foam material according to claim 1, characterized in that, The chain extender in component A is selected from one or more of glycerol, dipropylene glycol, and diethylene glycol.

19. The foam material according to claim 1, characterized in that, The viscosity of component B, polyphenylmethane polyisocyanate, is 150–800 cp.

20. The foam material according to claim 19, characterized in that, The component B, polyphenylmethane polyisocyanate, is one or more of Wanhua Chemical PM200, PM400, PM700, and BASF M20S.

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