Polyurethane foam material, preparation method thereof, and battery pack

Abstract

The present invention discloses a polyurethane foam material, a preparation method thereof, and a battery pack, which belongs to the technical field of polyurethane foam materials. The recovery resistance Rs of the polyurethane foam material has the following range: 2GPa≤Rs≤20GPa; the recovery resistance Rs is calculated according to the following formula: Rs=10 ‑9 ×P m / h s 2 Where, P m h is the maximum load of the compressed elastic section of the polyurethane foam material, in N; s The polyurethane foam material of the present invention has both high strength and high toughness and has heat preservation performance, and is suitable for use in battery packs.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane foam materials, and in particular to a polyurethane foam material and a preparation method thereof, as well as a battery pack. Background Art

[0002] With the rapid development of new energy electric vehicles, safety requirements for electric vehicles are becoming increasingly stringent. As the power source of new energy vehicles, the safety of the power battery pack is of paramount importance. In new energy vehicles, the battery pack is typically located under the vehicle chassis, connected to the chassis by bolts, leaving the lower surface of the battery pack exposed. During daily driving, flying stones and impacts from the bottom can cause the battery pack casing to deform or rupture, exposing the battery cells and potentially causing accidents.

[0003] New energy vehicles typically use lead-acid batteries, nickel-metal hydride batteries, and lithium batteries as power sources. For example, the optimal operating temperature range for common lithium batteries is between -20°C and 60°C. Below this temperature range, the battery's range is significantly reduced. Furthermore, in cold climates or during winter, when the battery is not in operation, heat loss from the battery pack increases over time, shortening the battery lifespan. This can result in the vehicle failing to start or requiring a long time to start.

[0004] At present, the thermal insulation materials used in the battery packs of new energy vehicles mainly include silica gel, aerogel, EPP, MPP, etc., but these materials cannot take into account both thermal insulation and impact resistance. Polyurethane foam material is an excellent thermal insulation material. However, the polyurethane foam materials in the prior art usually have poor toughness. When stones impact the surface of the polyurethane foam material, the material may be shattered. If the toughness of the polyurethane foam material is increased, its strength usually needs to be reduced. Then, when applied to the battery pack, the reduction in the strength of the polyurethane foam material will lead to increased deformation of the material under the same force, which in turn causes the battery pack box to deform. Summary of the Invention

[0005] To solve the above technical problems, the present invention aims to provide a polyurethane foam material and a preparation method thereof, as well as a battery pack. The polyurethane foam material of the present invention has both high strength and high toughness.

[0006] To achieve the above object, the present invention provides a polyurethane foam material in a first aspect, comprising a first surface and a second surface in a thickness direction; the polyurethane foam material has a recovery resistance Rs within the following range: 2 GPa ≤ Rs ≤ 20 GPa;

[0007] The recovery resistance Rs is calculated according to the following formula:

[0008] Rs=10 -9 ×P m / h s 2 ,

[0009] Where, P m is the maximum load of the compressed elastic section of the polyurethane foam material, in N;

[0010] h s is the elastic recovery displacement of the polyurethane foam material in the direction of the compressive load, in m;

[0011] The maximum load of the compression elastic section is obtained by testing according to the method described in GB / T 8813-2008;

[0012] The test method for elastic recovery displacement in the direction of compression load includes: performing compression test according to the method described in ASTM D 3574-08, with a maximum compression ratio of 75%, and the thickness of the sample after compression is recorded as h1; then the sample is placed at room temperature for 2 hours, and the thickness of the sample is measured again, which is recorded as h2; h is obtained by subtracting h2 from h1. s .

[0013] According to a specific embodiment of the present invention, preferably, the elasticity ratio b of the polyurethane foam material is greater than -0.3 and b is less than 0.5, and the elasticity ratio b is calculated according to the following formula:

[0014] ,

[0015] Wherein, ε1 is the elastic deformation rate of the polyurethane foam material, and ε2 is the plastic deformation rate of the polyurethane foam material. ε1 and ε2 are obtained by performing a tensile test according to the method described in ASTM D 3574-08.

[0016] According to a specific embodiment of the present invention, preferably, the hardness of the first surface is greater than the hardness of the second surface, and the difference in Shore C hardness between the first surface and the second surface is greater than 5.

[0017] According to a specific embodiment of the present invention, preferably, the surface roughness of the first surface is greater than the surface roughness of the second surface, and the difference between the surface roughness of the first surface and the surface roughness of the second surface is greater than 0.2 μm.

[0018] According to a specific embodiment of the present invention, preferably, the fire protection grade of the polyurethane foam material is UL94-V0.

[0019] According to a specific embodiment of the present invention, preferably, the density of the polyurethane foam material is 150-400 kg / m 3 .

[0020] According to a specific embodiment of the present invention, preferably, the thermal conductivity of the polyurethane foam material is ≤0.04 W / (m·K) when tested according to the method described in GB / T10295-2008.

[0021] According to a specific embodiment of the present invention, preferably, the elongation at break of the polyurethane foam material is 10%-40% when tested according to the method described in ASTM D 3574-08.

[0022] According to a specific embodiment of the present invention, preferably, the tensile strength of the polyurethane foam material is ≥3 MPa when tested according to the method described in ASTM D 3574-08.

[0023] According to a specific embodiment of the present invention, preferably, the polyurethane foam material is in sheet form, and its thickness is 3-20 mm.

[0024] According to a specific embodiment of the present invention, preferably, the polyurethane foam material meets the following conditions: a bending strength test is performed according to the method described in GB / T 8812.2-2007, and no fracture occurs under a deformation of 5%.

[0025] According to a specific embodiment of the present invention, preferably, the stone chip resistance of the second surface of the polyurethane foam material tested according to the method described in ISO 20567-1-2017 is ≤ level 1.

[0026] A second aspect of the present invention provides a method for preparing the above-mentioned polyurethane foam material, which comprises the following steps:

[0027] The foamable polyurethane composition is injected into a mold and cured to obtain the polyurethane foam material; wherein the mold includes a first mold body and a second mold body, the first mold body is located below the second mold body, the inner surface of the first mold body is preheated to 20-30°C, and the inner surface of the second mold body is preheated to 50-60°C.

[0028] According to a specific embodiment of the present invention, preferably, the surface of the polyurethane foam material formed by contacting the first mold body is the first surface, and the surface of the polyurethane foam material formed by contacting the second mold body is the second surface.

[0029] A third aspect of the present invention provides a battery pack, comprising:

[0030] A box body comprising an upper shell and a lower shell, a battery module contained between the upper shell and the lower shell, and a polyurethane foam material provided on the side and / or bottom of the box body, wherein the polyurethane foam material is the polyurethane foam material described above;

[0031] The first surface of the polyurethane foam material is the surface in contact with the side and / or bottom of the box body, and the second surface of the polyurethane foam material is the surface of the battery pack exposed to the outside.

[0032] The present invention has at least the following advantages and beneficial effects:

[0033] The polyurethane foam material of the present invention possesses both high strength and high toughness, resulting in excellent resistance to stone impact deformation. It also exhibits desirable flame retardancy and thermal insulation properties. The polyurethane foam material of the present invention is suitable for use in battery packs for new energy vehicles, providing support, cushioning, and thermal insulation, thereby improving safety and stability during vehicle operation. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0035] It should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0036] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0037] It will be understood that the terms “comprises,” “comprising,” and / or “containing” when used herein specify the presence of stated features, integers, steps, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

[0038] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0039] <Polyurethane foam material>

[0040] According to a specific embodiment of the present invention, the present invention provides a polyurethane foam material, comprising a first surface and a second surface in a thickness direction (i.e., two surfaces perpendicular or nearly perpendicular to the thickness); a recovery resistance Rs of the polyurethane foam material has the following range: 2 GPa ≤ Rs ≤ 20 GPa, for example, Rs is 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa, 9 GPa, 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, 16 GPa, 17 GPa, 18 GPa, 19 GPa, or 20 GPa; preferably, the recovery resistance Rs of the polyurethane foam material has the following range: 5 GPa ≤ Rs ≤ 10 GPa;

[0041] The recovery resistance Rs is calculated according to the following formula:

[0042] Rs=10 -9 ×P m / h s 2 ,

[0043] Where, P m is the maximum load of the compressed elastic section of the polyurethane foam material, in N;

[0044] h s is the elastic recovery displacement of the polyurethane foam material in the direction of the compressive load, in m;

[0045] The maximum load of the compression elastic section is obtained by testing according to the method described in GB / T 8813-2008;

[0046] The test method for elastic recovery displacement in the direction of compression load includes: performing a compression test according to the method described in ASTM D 3574-08, with a maximum compression ratio of 75% (i.e., compression to 25% of the original thickness of the sample), measuring the thickness of the sample after compression (the thickness is measured immediately after the compression test), and recording it as h1; then placing the sample at room temperature (i.e., 23±2°C) for 2 hours, and measuring the thickness of the sample again, and recording it as h2; h is obtained by subtracting h2 from h1. s .

[0047] Specifically, the sample used in the maximum load test of the compressive elastic segment and the elastic recovery displacement test in the compressive load direction can be approximately 50×50 mm in area and at least 5 mm in thickness. If the sample thickness is less than 5 mm, multiple samples can be stacked to achieve a thickness of at least 5 mm. A vernier caliper can be used to measure the sample thickness. During this test, the orientation of the first and second surfaces is not particularly restricted; in the specific tests in the following examples, the second surface faces upward. The instrument used for this test can be a UTM6104 electronic universal testing machine. The compressive force within the proportional limit (i.e., a distinct straight line portion in the force-displacement curve) (i.e., Fe) obtained by testing according to the method described in GB / T 8813-2008 is the maximum load of the compressive elastic segment. Compression testing is conducted according to the method described in ASTM D 3574-08, using TEST D. Before testing, the sample is conditioned at a temperature of (23±2)°C and a relative humidity of (50±5)%.

[0048] Normally, the strength and toughness of polyurethane foam materials are negatively correlated. Through research by the inventors, it was found that by controlling the recovery resistance Rs at 2GPa≤Rs≤20GPa, the polyurethane foam material has both high strength and high toughness, and thus has excellent resistance to stone impact deformation. This can not only avoid being crushed by flying stones, but also avoid damage to the battery pack case due to excessive deformation of the material under stress. If Rs is greater than 20GPa, the toughness of the polyurethane foam material is poor, and when the stone impacts the surface of the polyurethane foam material, the material will be crushed. If Rs is less than 2GPa, the strength of the polyurethane foam material is insufficient. When applied to the battery pack, the material is prone to excessive deformation when subjected to external force, resulting in damage to the battery pack case.

[0049] In some embodiments, the elasticity ratio b of the polyurethane foam material is greater than -0.3 and b is less than 0.5. For example, the elasticity ratio b is -0.29, -0.25, -0.20, -0.15, -0.10, -0.05, 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 or 0.49, and the elasticity ratio b is calculated according to the following formula:

[0050] ,

[0051] Wherein, ε1 is the elastic deformation rate of the polyurethane foam material, and ε2 is the plastic deformation rate of the polyurethane foam material. ε1 and ε2 are obtained by performing a tensile test according to the method described in ASTM D 3574-08.

[0052] Specifically, the tensile test was conducted according to the method described in ASTM D 3574-08, using Test E. The sample used in this test was dumbbell-shaped (this can be made using a special-shaped mold, as long as the internal surface temperatures of the first and second mold bodies are maintained within the ranges specified in this disclosure; or by cutting the sample). The dimensions were as described in FIG. 1 of Test E, and the thickness was the thickness of the sample prepared according to the examples below. The test was conducted in the longitudinal direction of the sample (i.e., longitudinal tensile), at a speed of (500±5) mm / min. The instrument used for this test was a UTM6104 electronic universal testing machine. ε1 and ε2 were obtained using the SUNS-FY-2000 software included with the instrument. Generally speaking, elastic deformation reflects the toughness of a material. Materials with high elastic deformation are able to maintain good shape stability when subjected to impact or pressure, thus avoiding fracture. Plastic deformation, on the other hand, reflects the material's ability to undergo stable, permanent deformation under external forces without compromising its integrity. The inventors have found through research that when the elasticity ratio b>-0.3 and b<0.5, it is conducive to a synergistic effect with the recovery resistance Rs, further enabling the material to have both higher strength and higher toughness.

[0053] In some embodiments, the hardness of the first surface is greater than that of the second surface, and the difference in Shore C hardness between the first and second surfaces is greater than 5. By further controlling the hardness of the first surface to be greater than that of the second surface, and keeping the difference within the aforementioned range, the present invention further facilitates the material's combination of high strength and high toughness. This allows it to effectively resist impact and prevent excessive deformation when struck by a stone, further enhancing the polyurethane foam's resistance to stone impact deformation. Specifically, the softer second surface absorbs the instantaneous impact energy, which is then gradually transferred to the harder first surface. By controlling the hardness difference within the aforementioned range, low-frequency vibrations and residual stresses generated during the impact transfer process are fully eliminated, effectively preventing the impact. Furthermore, the softer second surface reduces the rebound rate of the impact force, while the harder first surface provides support, preventing excessive deformation. Preferably, the Shore C hardness of the first surface is 90-98, and the Shore C hardness of the second surface is 82-90. The polyurethane foam material of the present invention has a Shore C hardness of 80 or higher on both surfaces, making it a rigid polyurethane foam. The Shore C hardness is measured according to the method described in ASTM D2240-05 (2010). If the Shore C hardness of the first and second surfaces is below the above range, the polyurethane foam material is too soft, resulting in insufficient strength. If the Shore C hardness of the first and second surfaces is above the above range, the polyurethane foam material is too hard, resulting in poor toughness.

[0054] In some embodiments, the surface roughness of the first surface is greater than the surface roughness of the second surface, and the difference between the surface roughness of the first surface and the surface roughness of the second surface is greater than 0.2 μm. The present invention further helps to make the material have both high strength and high toughness by further controlling the surface roughness of the first surface to be greater than the surface roughness of the second surface and controlling the difference between the two to be within the above range. Surface roughness (R z ) is measured according to the method described in ISO 4287-1997. Preferably, the surface roughness of the first surface is 0.60-0.80 μm, and the surface roughness of the second surface is 0.40-0.55 μm. By further controlling the roughness of the first surface within the above range, the present invention achieves enhanced bonding properties on the first surface, enabling a better fit when the polyurethane foam material is assembled with an adhesive. Furthermore, by controlling the roughness of the first surface within this range, the first surface possesses a suitable microscopic concave-convex structure, which helps disperse external forces, thereby further enhancing the strength of the polyurethane foam material. If the roughness of the first surface falls below the above range, the polyurethane foam material's bonding properties and strength are insufficient. If the roughness of the first surface exceeds this range, the polyurethane foam material is susceptible to scratching and excessively compressing the case. Furthermore, by further controlling the roughness of the second surface within the above range, the present invention achieves a smoother second surface, resulting in a more uniform stress distribution when struck by a stone, further enhancing the polyurethane foam material's toughness and making it less susceptible to shattering. If the roughness of the second surface is lower than the above range, the exposed second surface is easily scratched, resulting in material damage; if the roughness of the second surface is higher than the above range, the toughness of the polyurethane foam material is insufficient.

[0055] In some embodiments, the polyurethane foam material has a fire rating of UL94-V0. The fire rating of the polyurethane foam material is obtained by using a vertical burning test according to the method described in UL94.

[0056] In some embodiments, the density of the polyurethane foam material is 150-400 kg / m 3 , for example 150kg / m 3 、160kg / m 3 、170kg / m 3 、180kg / m 3 、190kg / m 3 , 200kg / m 3 , 210kg / m 3 , 220kg / m 3 , 230kg / m 3, 240kg / m 3 , 250kg / m 3 , 260kg / m 3 , 270kg / m 3 , 280kg / m 3 , 290kg / m 3 、300kg / m 3 、310kg / m 3 、320kg / m 3 、330kg / m 3 、340kg / m 3 、350kg / m 3 、360kg / m 3 、370kg / m 3 、380kg / m 3 、390kg / m 3 or 400kg / m 3 etc., preferably 250-350kg / m 3 The density of the polyurethane foam material is obtained by testing according to the method described in ASTM-3574-08. It should be noted that the density of the polyurethane foam material refers to the overall density of the polyurethane foam material prepared according to the preparation method of the specific embodiment of the present invention. When the density is 150-400 kg / m 3 When the density is within the above range, the polyurethane foam material has better thermal insulation performance and is conducive to meeting the Rs of the present invention. If the density is greater than the above range, the thermal conductivity of the polyurethane foam material will be too high, resulting in poor thermal insulation performance; if the density is less than the above range, the Rs of the polyurethane foam material will be too small.

[0057] In some embodiments, the thermal conductivity of the polyurethane foam material is ≤0.04 W / (m·K), such as 0.04 W / (m·K), 0.03 W / (m·K), 0.02 W / (m·K), or 0.01 W / (m·K), as tested according to the method described in GB / T 10295-2008. By controlling the thermal conductivity within the above range, the polyurethane foam material has excellent thermal insulation properties.

[0058] In some embodiments, the elongation at break of the polyurethane foam material is 10%-40% as tested according to the method described in ASTM D 3574-08, for example, 10%, 15%, 20%, 25%, 30%, 35% or 40%. The present invention further controls the elongation at break within the above range, thereby further enabling the polyurethane foam material to have both high strength and high toughness. If the elongation at break is greater than the above range, the polyurethane foam material will recover too quickly and to a too high degree after being compressed; at the same time, the polyurethane foam material will produce excessive elastic deformation after being stretched; both of which result in insufficient strength of the material. If the elongation at break is less than the above range, the polyurethane foam material will recover too difficultly after being compressed; at the same time, the polyurethane foam material will not produce sufficient elastic deformation after being stretched; both of which result in insufficient toughness of the material.

[0059] In some embodiments, the polyurethane foam material has a tensile strength of ≥3 MPa, preferably 3-10 MPa, such as 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa, as tested according to ASTM D 3574-08. If the tensile strength is too high, the material has poor toughness; if the tensile strength is too low, the material has insufficient strength.

[0060] In some embodiments, the polyurethane foam material is in sheet form and has a thickness of 3-20 mm, for example, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm.

[0061] In some embodiments, the polyurethane foam material meets the following conditions: It does not break when subjected to a 5% deformation in a flexural strength test performed according to the method described in GB / T 8812.2-2007. Specifically, the sample is conditioned at a temperature of (23±2)°C and a relative humidity of (50±5)% before testing. During the test, the load head travels at a speed of (20±1) mm / min. When the polyurethane foam material meets these conditions, it further facilitates the material's ability to achieve both high strength and high toughness.

[0062] In some embodiments, the polyurethane foam material has a stone chip resistance of the second surface of ≤1 when tested according to the method described in ISO 20567-1-2017. Specifically, a clamp is used to clamp the sample on a 100×100 mm test plate, and the first surface of the sample is attached to the test plate (no adhesive is required) to test the stone chip resistance of the second surface. Before the test, the test plate holding the sample is conditioned at a temperature of (23±2)°C and a relative humidity of (50±5)%. The test is carried out according to the conditions of Method A in Table 2, and the grades are divided as described in Figure 3. The stone chip resistance grade ≤1 includes Rating 0.5 (i.e., grade 0.5) and Rating 1.0 (i.e., grade 1) in Figure 3. The area of ​​the sample used in the test can be approximately 100×100 mm, and the thickness is the thickness of the sample prepared according to the examples below. When the stone impact resistance level of the second surface is greater than 1, when impacted by stones, slight dents or pits may appear on the sides and / or bottom of the box body that is in contact with the polyurethane foam material, or even cracks or other damage may occur.

[0063] <Foamable polyurethane composition>

[0064] In some embodiments, the foamable polyurethane composition of the present invention includes a polyol-containing composition and an isocyanate.

[0065] (Polyol)

[0066] In some embodiments, the polyol-containing composition includes a first polyol and a second polyol; the first polyol has a hydroxyl value of 300-500 mgKOH / g and a functionality of 3-5; the second polyol has a hydroxyl value of 20-112 mgKOH / g and a functionality of 2-3.

[0067] In some embodiments, the weight ratio of the first polyol to the second polyol is (4:1)-(1:1). The two polyols used in the present invention have different reactivity due to differences in hydroxyl value and functionality. Specifically, the first polyol has a higher hydroxyl value and functionality and a higher reactivity; the second polyol has a lower hydroxyl value and functionality and a lower reactivity. During the reaction, in a molecular chain of the same length, if the content of the first polyol is too high, the content of isocyanate will also be too high, and the polyurethane foam material mainly provides hardness by the isocyanate segment as a hard segment. When the content of the first polyol is too high, the polyurethane foam material has too many hard segments in the molecular chain, resulting in an excessively large Rs. Conversely, if the content of the second polyol is too high, Rs will be too small.

[0068] According to a specific embodiment of the present invention, by adopting the above-mentioned first polyol and second polyol and the ratio range between the two, it is beneficial to make the recovery resistance Rs of the polyurethane foam material within the above-mentioned range of the present invention.

[0069] In some embodiments, the first polyol includes, but is not limited to, one or more of sucrose polyether polyol, castor oil-based polyether polyol, and sorbitol polyether polyol. Specifically, the first polyol includes, but is not limited to, at least one of NJ-4110 (hydroxyl value 440 mgKOH / g, functionality 4), NJ-8336 (hydroxyl value 365 mgKOH / g, functionality 4), A-30 (hydroxyl value 400 mgKOH / g, functionality 3), NJ-6305B (hydroxyl value 500 mgKOH / g, functionality 4.5), PURANOL RF3777M (hydroxyl value 450 mgKOH / g, functionality 4), and WANOL® R2490 (hydroxyl value 490 mgKOH / g, functionality 3).

[0070] In some embodiments, the second polyol includes, but is not limited to, one or more of polymer polyols, propylene glycol polyether polyols, and tetramethylene glycol polyether polyols. Specifically, the second polyol includes, but is not limited to, at least one of VORANOL 4701 (hydroxyl value 34 mgKOH / g, functionality 3), NJ-330N (hydroxyl value 34 mgKOH / g, functionality 3), NJ-360 (hydroxyl value 28 mgKOH / g, functionality 3), NJ-3628 (hydroxyl value 28 mgKOH / g, functionality 3), NJ-210 (hydroxyl value 112 mgKOH / g, functionality 2), and CHP-H45 (hydroxyl value 21 mgKOH / g, functionality 3).

[0071] (flame retardant)

[0072] In some embodiments, the polyol-containing composition further comprises a flame retardant.

[0073] In some embodiments, the flame retardant is present in an amount of 15% to 30% of the total weight of the first polyol, the second polyol, and the flame retardant.

[0074] In some embodiments, the flame retardant includes, but is not limited to, one or more of tris(1-chloro-2-propyl) phosphate, tris(1,3-dichloroisopropyl) phosphate, tris(2-chloroethyl) phosphate, dimethyl methyl phosphate, diethyl ethyl phosphate, resorcinol bis(diphenyl phosphate), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc. Preferably, the flame retardant is selected from one or more of tris(1-chloro-2-propyl) phosphate, dimethyl methyl phosphate, and diethyl ethyl phosphate.

[0075] According to specific embodiments of the present invention, the use of a flame retardant can improve the polyurethane foam material's flame retardancy and improve the flowability of the foamable polyurethane composition, thereby imparting a more desirable appearance to the polyurethane foam material. However, if the flame retardant content exceeds the aforementioned range, the toughness of the polyurethane foam material may be too low. When the flame retardant content is within the aforementioned range, the polyurethane foam material can achieve a UL94-V0 fire rating while also maintaining an Rs within the aforementioned range of the present invention.

[0076] (Chain Extender)

[0077] In some embodiments, the polyol-containing composition further comprises a chain extender.

[0078] In some embodiments, the content of the chain extender is 1%-10%, preferably 3%-10%, of the total weight of the first polyol, the second polyol and the flame retardant.

[0079] In some embodiments, the chain extender can be selected from at least one of small molecule diols, such as but not limited to: one or more of ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, etc.

[0080] According to a specific embodiment of the present invention, by using a chain extender, the molecular weight of the polyurethane foam material can be increased, and short-chain molecules can be converted into long-chain molecules, thereby facilitating the polyurethane foam material to have an Rs within the above-mentioned range of the present invention.

[0081] (cross-linking agent)

[0082] In some embodiments, the polyol-containing composition further includes a cross-linking agent.

[0083] In some embodiments, the content of the crosslinking agent is 1%-5%, preferably 1%-3%, of the total weight of the first polyol, the second polyol and the flame retardant. If the amount of the crosslinking agent is higher than the above range, the hard segments of the molecular chain of the polyurethane foam material will be too much, resulting in the P m If the amount of the crosslinking agent is too large, the Rs will be too large. On the contrary, if the amount of the crosslinking agent is lower than the above range, the Rs of the material will be too small. When the content of the crosslinking agent is within the above range, it is beneficial for the polyurethane foam material to have an Rs within the above range of the present invention.

[0084] In some embodiments, the cross-linking agent may be at least one selected from amine-containing cross-linking agents, such as, but not limited to, one or more of triethanolamine, diethanolamine, triisopropanolamine, methyldiethanolamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, dimethylthiotoluenediamine, and diethyltoluenediamine. Preferably, the cross-linking agent is selected from one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, dimethylthiotoluenediamine, and diethyltoluenediamine.

[0085] (foaming agent)

[0086] In some embodiments, the polyol-containing composition further comprises a blowing agent.

[0087] In some embodiments, the content of the blowing agent is 20%-31% of the total weight of the first polyol, the second polyol and the flame retardant.

[0088] In some embodiments, the foaming agent includes a physical foaming agent and water; preferably, the water content is 0.15%-0.7%, more preferably 0.15%-0.5%, of the total weight of the first polyol, the second polyol and the flame retardant.

[0089] In some embodiments, the physical foaming agent includes a first foaming agent and a second foaming agent. The first foaming agent is selected from at least one of alkanes and fluorocarbons, and the second foaming agent is selected from at least one of carbonates. Examples of the first foaming agent include, but are not limited to, one or more of 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, n-pentane, and cyclopentane. Examples of the second foaming agent include, but are not limited to, one or more of sodium bicarbonate, ammonium carbonate, and magnesium carbonate.

[0090] In some embodiments, the mass of the first foaming agent is 2-3 times the mass of the second foaming agent.

[0091] According to a specific embodiment of the present invention, by using a mixture of two physical foaming agents and water as a foaming agent, the polyurea generated after the reaction of water and isocyanate can be reduced, thereby facilitating the polyurethane foam material to have an Rs within the above range of the present invention.

[0092] (catalyst)

[0093] In some embodiments, the polyol-containing composition further comprises a catalyst.

[0094] In some embodiments, the content of the catalyst is 0.1%-0.5% of the total weight of the first polyol, the second polyol and the flame retardant.

[0095] In some embodiments, the catalyst can be selected from at least one of an amine catalyst and an organometallic catalyst, such as but not limited to: amine catalysts such as triethylamine, triethylenediamine, dimethylethanolamine, dimethylaminoethanol, N-methylmorpholine, N,N-dimethylcyclohexylamine, N,N',N'-trimethylaminoethylpiperazine, tetraethylammonium hydroxide, imidazole, 2-ethyl-4-methylimidazole, etc.; tin catalysts such as stannous octoate; bismuth catalysts such as bismuth trioctoate.

[0096] (Other functional additives)

[0097] In some embodiments, the polyol-containing composition may optionally include other functional additives. Examples of these other functional additives include, but are not limited to, one or more of the following: foam stabilizers (such as, but not limited to, silicone oil), antioxidants, antistatic agents, colorants, and anti-hydrolysis agents. The content of these other functional additives can be adjusted conventionally according to techniques in the art and is not particularly limited in the present invention.

[0098] (isocyanate)

[0099] In some embodiments, the isocyanate includes, but is not limited to, one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, liquefied diphenylmethane diisocyanate, and polymerized diphenylmethane diisocyanate. Preferably, the isocyanate is selected from one or more of diphenylmethane diisocyanate, liquefied diphenylmethane diisocyanate, and polymerized diphenylmethane diisocyanate. According to specific embodiments of the present invention, preferably linear and / or low-functionality isocyanates are used to facilitate achieving an Rs within the aforementioned range of the present invention in the polyurethane foam material.

[0100] In some embodiments, the molar ratio of -NCO (isocyanate group) of the isocyanate to the total -OH (hydroxyl group) of the first polyol and the second polyol is (0.95-1.05):1. Specifically, the weight ratio of the polyol-containing composition to the isocyanate is 100:(60-100). If the amount of isocyanate is too much, the hard segments of the molecular chain of the polyurethane foam material will be too much, resulting in the P m If the amount of isocyanate is too large, the Rs will be too large. On the contrary, if the amount of isocyanate is too small, the Rs of the material will be too small. When the amount of isocyanate is within the above range, it is beneficial for the polyurethane foam material to have an Rs within the above range of the present invention.

[0101] <Preparation method of polyurethane foam material>

[0102] According to a specific embodiment of the present invention, the present invention provides a method for preparing a polyurethane foam material, which comprises the following steps:

[0103] The foamable polyurethane composition is injected into a mold and cured (reacts and foams during the curing process) to obtain the polyurethane foam material; wherein the mold includes a first mold body and a second mold body, the first mold body is located below the second mold body, the inner surface of the first mold body is preheated to 20-30°C, preferably 20-25°C, and the inner surface of the second mold body is preheated to 50-60°C, preferably 50-55°C.

[0104] In some embodiments, the first mold body and the second mold body respectively have a cavity. When in use, the edges of the first mold body and the second mold body are in contact and connected, and the cavities of the first mold body and the second mold body are connected to form a shaping cavity. The shaping cavity can be a regular cube or an irregular shape. The size of the plastic cavity is preferably: an area of ​​10 mm × 10 mm to 1000 mm × 1000 mm, and a thickness of 3-20 mm. It should be noted that the thickness of the shaping cavity is the thickness of the prepared polyurethane foam material, so the thickness refers to the distance between the upper surface and the lower surface of the plastic cavity.

[0105] In some embodiments, the preparation method further comprises the following steps: spraying a release agent on the inner surfaces of the first mold body and the second mold body before injecting the foamable polyurethane composition into the mold. The release agent can be a conventional release agent in the art and is not particularly limited in the present invention.

[0106] According to a specific embodiment of the present invention, when the inner surface temperatures of the first mold body and the second mold body are within the above-mentioned range, the molecular chain movement rates of the two surfaces of the foamable polyurethane composition are different during the foaming process. When injected into the first mold body located below, the molecular chain moves slowly, generating residual stress or phase change, while the molecular chain on the side in contact with the second mold body moves faster, which is beneficial to satisfying the Rs of the present invention, and is beneficial to making the side of the polyurethane foam material in contact with the first mold body have excellent strength, and at the same time is beneficial to making the side of the polyurethane foam material in contact with the second mold body have excellent toughness, which is beneficial to having both higher strength and higher toughness.

[0107] Furthermore, when the foamable polyurethane composition is injected into the first mold body located below, the reaction rate is slowed, thereby improving the fluidity of the foamable polyurethane composition, thereby better filling the mold cavity and reducing the occurrence of defects such as cavitation and material shortages during the production process. Furthermore, this eliminates the problem of color difference in the blanking line caused by the overly rapid reaction of the portion that first contacts the overheated mold body when the foamable polyurethane composition is injected into a mold with a temperature higher than the inner surface temperature of the first mold body.

[0108] At the same time, when the inner surface temperature of the first mold body is within the above-mentioned range, the release agent evaporates more slowly during spraying, resulting in a lower packing density after complete volatilization. This increases the roughness of the first mold body surface after spraying the release agent relative to the surface of a mold body with a mold temperature higher than the above-mentioned range. This, in turn, helps the polyurethane foam material form a rougher first surface. Furthermore, if the inner surface temperature of the first mold body is higher than the above-mentioned range, the release agent molecules move too quickly, causing more release agent to transfer to the material when the polyurethane foam material is demolded after production is complete. Therefore, in the present invention, when the inner surface temperature of the first mold body is within the above-mentioned range, the first surface formed is advantageously less residual release agent and has a surface roughness within the above-mentioned range. Furthermore, when the inner surface temperature of the second mold body is within the above-mentioned range, the second surface formed is advantageously advantageously provided with a surface roughness within the above-mentioned range.

[0109] In some embodiments, the preparation method further comprises the following steps before injecting the foamable polyurethane composition into the mold: sequentially mixing the polyol-containing composition and the isocyanate for a first time, a second time, and a third time to obtain the foamable polyurethane composition; the first mixing is carried out at 35-40°C under stirring conditions, the stirring speed of the first mixing is 60 r / min or more, and the first mixing time is 30 minutes or more; the second mixing is carried out at 28-32°C under stirring conditions, the stirring speed of the second mixing is 5000-8000 r / min, and the second mixing time is 5 seconds or more; the third mixing is carried out in a static mixer. Specifically, the length of the static mixer is 20 cm or more.

[0110] According to a specific embodiment of the present invention, three mixings are performed before the foamable polyurethane composition is injected into the mold. When the conditions of the three mixings are within the above-mentioned range, the foamable polyurethane composition injected into the mold forms crystal chains during crystallization, which is beneficial for the polyurethane foam material to have an Rs within the above-mentioned range of the present invention.

[0111] In some embodiments, the thickness of the first mold body and the second mold body are respectively 3-20 mm, preferably 3-10 mm.

[0112] In some embodiments, the curing time is 5-20 minutes, preferably 8-12 minutes.

[0113] In some embodiments, the method for preparing the polyurethane foam material may specifically include the following steps:

[0114] (1) uniformly mixing a first polyol, a second polyol, a flame retardant, a chain extender, a cross-linking agent, a catalyst, other functional additives optionally added, and a foaming agent to obtain a polyol-containing composition (component A);

[0115] (2) The polyol-containing composition (component A) and the isocyanate (component B) are mixed for a first time at 35-40° C. under stirring conditions, the stirring speed of the first mixing is 60 r / min or more, and the first mixing time is more than 30 minutes. Then, the polyol-containing composition (component A) and the isocyanate (component B) are mixed for a second time at 28-32° C. under stirring conditions, the stirring speed of the second mixing is 5000-8000 r / min, and the second mixing time is more than 5 seconds. Then, the polyol-containing composition and the isocyanate (component B) are mixed for a third time in a static mixer to obtain a foamable polyurethane composition.

[0116] (3) injecting the foamable polyurethane composition into a mold, and obtaining the polyurethane foam material after curing; wherein the mold comprises a first mold body and a second mold body, the first mold body is located below the second mold body, the inner surface of the first mold body is preheated to 20-30°C, preferably 20-25°C, and the inner surface of the second mold body is preheated to 50-60°C, preferably 50-55°C.

[0117] <Application>

[0118] The polyurethane foam material of the present invention combines high strength and toughness, and also exhibits ideal flame retardancy and thermal insulation properties. It can be used in various supporting materials, cushioning materials, and thermal insulation materials, such as, but not limited to, battery packs. Specifically, the polyurethane foam material of the present invention is particularly suitable for use in new energy power battery packs.

[0119] According to a specific embodiment of the present invention, the present invention provides a battery pack, comprising:

[0120] A box body comprising an upper shell and a lower shell, a battery module contained between the upper shell and the lower shell, and a polyurethane foam material arranged on the side and / or bottom of the box body, wherein the polyurethane foam material is the above-mentioned polyurethane foam material; the first surface of the polyurethane foam material is the surface that fits with the side and / or bottom of the box body, and the second surface of the polyurethane foam material is the surface of the battery pack exposed to the outside.

[0121] The polyurethane foam material of the present invention is suitable for use in battery packs of new energy vehicles, plays supporting, cushioning and heat-insulating roles, has excellent anti-stone impact deformation performance, and can improve the safety and stability of the vehicle during operation.

[0122] <Example>

[0123] The technical solutions of the present invention are specifically described below through examples, but the present invention is not limited to these examples and can of course be implemented with various modifications within the scope of the gist of the present invention.

[0124] Example 1

[0125] In parts by weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 10 parts of ethylene glycol, 1 part of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.5 parts of water, 1 part of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed mixer and mixed to obtain component A (i.e., a polyol-containing composition); 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer and mixed to obtain component B; component A and component B were mixed in a mass ratio of 100:75 for the first time (stirred at a speed of 80 r / min for 30 minutes in a material tank at 35°C), the second time The foamable polyurethane composition is mixed (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and the temperature is 30°C) and mixed for the third time (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body (i.e., an upper mold body) with a thickness of 5 mm and a first mold body (i.e., a lower mold body) with a thickness of 5 mm, the inner surface of the second mold body is preheated to 55°C, and the inner surface of the first mold body is preheated to 25°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631. After curing for 10 minutes, the composition is removed to obtain a polyurethane foam material.

[0126] Example 2

[0127] In parts by weight, 30 parts of NJ-3628, 60 parts of NJ-6305B, 20 parts of diethyl ethyl phosphate, 5 parts of 1,4-butanediol, 2 parts of triisopropanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.2 parts of water, 1 part of silicone oil, and 0.4 parts of triethylenediamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a mass ratio of 100:100 for the first time (in a material tank, stirred at a speed of 80r / min for 30min at 35°C), the second The foamable polyurethane composition was obtained by a second mixing (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and at a temperature of 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing). The foamable polyurethane composition was injected into a mold, which included a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm. The inner surface of the second mold body was preheated to 55°C, and the inner surface of the first mold body was preheated to 25°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body were sprayed with a release agent 631. After curing for 10 minutes, the composition was removed to obtain a polyurethane foam material.

[0128] Example 3

[0129] In parts by weight, 40 parts of NJ-330N, 45 parts of NJ-4110, 15 parts of resorcinol bis(diphenyl phosphate), 1.5 parts of dipropylene glycol, 5 parts of methyldiethanolamine, 20 parts of 1,1,1,3,3-pentafluoropropane, 10 parts of sodium bicarbonate, 0.3 parts of water, 0.9 parts of silicone oil, and 0.5 parts of N-methylmorpholine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a first mixing process in a mass ratio of 100:65 (stirred at a speed of 80 r / min for 30 min in a material tank at 35°C). n), a second mixing (flowing through the mixing chamber in the mixing chamber of the injection head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and the temperature is 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; injecting the foamable polyurethane composition into a mold, the mold comprising a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body being preheated to 55°C, and the inner surface of the first mold body being preheated to 25°C, and before injecting the foamable polyurethane composition, spraying a release agent 631 on the inner surfaces of the first mold body and the second mold body, and curing for 10 minutes, taking out to obtain a polyurethane foam material.

[0130] Example 4

[0131] In parts by weight, 30 parts of NJ-330N, 40 parts of NJ-4110, 30 parts of tris(1-chloro-2-propyl) phosphate, 10 parts of 1,6-hexanediol, 3 parts of diethyltoluenediamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 1 part of silicone oil, and 0.5 parts of dimethylaminoethanol were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a first mixing order at a mass ratio of 100:90 (stirred at a speed of 80 r / min for 30 min in a material tank at 35°C). n), a second mixing (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and the temperature is 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body is preheated to 60°C, and the inner surface of the first mold body is preheated to 20°C, and before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631, and after curing for 10 minutes, it is taken out to obtain a polyurethane foam material.

[0132] Example 5

[0133] In parts by weight, 16 parts of VORANOL 4701, 64 parts of A-30, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of ammonium carbonate, 0.25 parts of water, 0.5 parts of silicone oil, and 0.1 parts of imidazole were added to a high-speed blender and mixed to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender and mixed to obtain component B; components A and B were mixed in a mass ratio of 100:80 for the first time (in a material tank, at 35°C and at a speed of 80 r / min for 30 minutes), the second time (in a mixing head of a material injection machine), and the mixture was stirred for 1 minute. The foamable polyurethane composition is passed through a mixing chamber at a stirring speed of 8000 r / min, the time of passing through the mixing chamber is more than 5 seconds, and the temperature is 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body is preheated to 50°C, and the inner surface of the first mold body is preheated to 30°C, and before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631. After curing for 10 minutes, the composition is taken out to obtain a polyurethane foam material.

[0134] Example 6

[0135] In parts by weight, 40 parts of VORANOL 4701, 40 parts of A-30, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of cyclopentane, 6 parts of sodium bicarbonate, 0.5 parts of water, 0.5 parts of silicone oil, and 0.1 parts of stannous octoate were added to a high-speed blender and mixed to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender and mixed to obtain component B; components A and B were mixed in a mass ratio of 100:70 for the first time (in a material tank, at 35°C and a speed of 80 r / min for 30 minutes), and for the second time (in a mixing chamber of an injection head at 80 00r / min through a mixing chamber for more than 5s at a temperature of 30°C) and a third mixing (flowing through a static mixer with a length of 25cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5mm and a first mold body with a thickness of 5mm, the inner surface of the second mold body is preheated to 50°C, and the inner surface of the first mold body is preheated to 30°C, and before injecting the foamable polyurethane composition, a release agent 631 is sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 minutes, the material is taken out to obtain a polyurethane foam material.

[0136] Example 7

[0137] In parts by weight, 40 parts of PURANOL RF3777M, 40 parts of NJ210, 20 parts of dimethyl methyl phosphate, 3 parts of ethylene glycol, 1 part of diethanolamine, 15 parts of n-pentane, 5 parts of magnesium carbonate, 0.5 parts of water, 0.5 parts of silicone oil, and 0.1 parts of stannous octoate were added to a high-speed mixer and mixed to obtain component A; 100 parts of diphenylmethane diisocyanate was used as component B; components A and B were mixed in a mass ratio of 100:60 for the first time (stirring at a speed of 80 r / min for 30 minutes in a material tank at 35°C), the second time (flowing through the mixing chamber of the injection head at a stirring speed of 8000 r / min), and the mixture was stirred for 30 minutes. The foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body is preheated to 50°C, and the inner surface of the first mold body is preheated to 30°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631. After curing for 10 minutes, the material is taken out to obtain a polyurethane foam material.

[0138] Example 8

[0139] In parts by weight, 60 parts of WANOL® R2490, 15 parts of CHP-H45, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 0.5 parts of silicone oil, and 0.1 parts of stannous octoate were added to a high-speed mixer and mixed to obtain component A; 100 parts of hexamethylene diisocyanate was used as component B; components A and B were mixed in a mass ratio of 100:100 in sequence for the first time (stirring at 80 r / min for 30 min in a material tank at 35°C), the second time (stirring at 8000 r / min in the mixing chamber of the injection head), and the mixture was stirred for 1 minute. The foamable polyurethane composition is mixed by mixing the mixture through a mixing chamber at a stirring speed of 500 nm and a time of more than 5 seconds in the mixing chamber at a temperature of 30°C) and a third mixing (mixing by mixing the mixture through a static mixer with a length of 25 cm) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, the mold comprising a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body being preheated to 50°C and the inner surface of the first mold body being preheated to 30°C, and before injecting the foamable polyurethane composition, a release agent 631 is sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 minutes, the composition is taken out to obtain a polyurethane foam material.

[0140] Comparative Example 1

[0141] In parts by weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 1.4 parts of water, 1 part of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; components A and B were mixed in a mass ratio of 100:90 for the first time (in a material tank, at 35°C and a speed of 80r / min for 30min), the second time (in the mixing chamber of the injection head) The foamable polyurethane composition was passed through a mixing chamber at a stirring speed of 8000 r / min, the time of passing through the mixing chamber was more than 5 seconds, and the temperature was 30°C) and mixed for a third time (passed through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition was injected into a mold, which included a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body was preheated to 55°C, and the inner surface of the first mold body was preheated to 25°C, and before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body were sprayed with a release agent 631. After curing for 10 minutes, the composition was removed to obtain a polyurethane foam material.

[0142] Comparative Example 2

[0143] In parts by weight, 40 parts of NJ-330N, 50 parts of NJ-4110, 10 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 1 part of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a mass ratio of 100:70 for the first time (stirred at a speed of 80r / min for 30min in a material tank at 35°C), the second time The foamable polyurethane composition is mixed (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and the temperature is 30°C) and mixed for the third time (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body is preheated to 55°C, and the inner surface of the first mold body is preheated to 55°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631. After curing for 10 minutes, the composition is removed to obtain a polyurethane foam material.

[0144] Comparative Example 3

[0145] In parts by weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 0.9 parts of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a mass ratio of 100:90 for the first time (in a material tank, stirred at a speed of 80r / min for 30min at 35°C), the second The foamable polyurethane composition was obtained by a second mixing (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and at a temperature of 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing). The foamable polyurethane composition was injected into a mold, which included a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm. The inner surface of the second mold body was preheated to 25°C, and the inner surface of the first mold body was preheated to 25°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body were sprayed with a release agent 631. After curing for 10 minutes, the composition was taken out to obtain a polyurethane foam material.

[0146] Comparative Example 4

[0147] In parts by weight, 80 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 1 part of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a mass ratio of 100:110 for the first time (in a material tank, at 35°C, at a speed of 80r / min for 30min), the second time (in the injection molding machine), and the mixture was stirred for 1 minute. The foamable polyurethane composition is obtained by mixing the polyurethane foam in a mixing chamber of a feeder head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds and at a temperature of 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing) to obtain a foamable polyurethane composition; the foamable polyurethane composition is injected into a mold, which includes a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm, the inner surface of the second mold body is preheated to 55°C, and the inner surface of the first mold body is preheated to 25°C, and before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body are sprayed with a release agent 631. After curing for 10 minutes, the polyurethane foam is taken out to obtain a polyurethane foam material.

[0148] Comparative Example 5

[0149] In parts by weight, 60 parts of NJ-330N, 20 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 0.5 parts of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender for mixing to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender for mixing to obtain component B; component A and component B were mixed in a mass ratio of 100:45 for the first time (stirred at a speed of 80r / min for 30min in a material tank at 35°C), the second The foamable polyurethane composition was obtained by a second mixing (flowing through the mixing chamber of the injection molding machine head at a stirring speed of 8000 r / min, flowing through the mixing chamber for more than 5 seconds, and at a temperature of 30°C) and a third mixing (flowing through a static mixer with a length of 25 cm for mixing). The foamable polyurethane composition was injected into a mold, which included a second mold body with a thickness of 5 mm and a first mold body with a thickness of 5 mm. The inner surface of the second mold body was preheated to 55°C, and the inner surface of the first mold body was preheated to 25°C. Before injecting the foamable polyurethane composition, the inner surfaces of the first mold body and the second mold body were sprayed with a release agent 631. After curing for 10 minutes, the composition was removed to obtain a polyurethane foam material.

[0150] Comparative Example 6

[0151] In parts by weight, 30 parts of NJ-330N, 60 parts of NJ-4110, 20 parts of dimethyl methyl phosphate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of 1,1,1,3,3-pentafluoropropane, 6 parts of sodium bicarbonate, 0.3 parts of water, 1 part of silicone oil, and 0.5 parts of N,N-dimethylcyclohexylamine were added to a high-speed blender and mixed to obtain component A; 80 parts of polymerized diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed blender and mixed to obtain component B; component A and component B were mixed only once at a mass ratio of 100:95 (i.e., the second step in the above embodiment). The method further comprises the steps of: injecting the foamable polyurethane composition into a mold, wherein the mold comprises a second mold body having a thickness of 5 mm and a first mold body having a thickness of 5 mm, wherein the inner surface of the second mold body is preheated to 55° C., and the inner surface of the first mold body is preheated to 25° C., and before injecting the foamable polyurethane composition, spraying a release agent 631 on the inner surfaces of the first mold body and the second mold body. The foamable polyurethane composition is cured for 10 minutes and then removed to obtain a polyurethane foam material.

[0152] After testing various characteristics of the polyurethane foam materials of the above examples and comparative examples, the results are shown in Tables 1 and 2.

[0153] Table 1 Characteristics of the embodiment

[0154]

[0155] Table 2 Characteristics of comparative examples

[0156]

[0157] It can be seen from Table 1 and Table 2 that the embodiments of the present invention control the recovery resistance Rs to be 2GPa≤Rs≤20GPa, so that the polyurethane foam material has both high strength and high toughness, and thus has excellent anti-stone impact deformation performance, which can avoid being crushed by flying stones and avoid damage to the battery pack box due to excessive deformation of the material under stress; while the recovery resistance Rs of the comparative examples is not within the range controlled by the present invention, and the polyurethane foam materials of the comparative examples either have insufficient bending strength, insufficient stone impact resistance grade, or insufficient bending strength and stone impact resistance grade, and do not have excellent stone impact deformation performance.

Claims

1. A polyurethane foam material, wherein: The polyurethane foam material includes a first surface and a second surface in a thickness direction; the restoration resistance Rs of the polyurethane foam material has the following range: 2GPa≤Rs≤20GPa; The recovery resistance Rs is calculated according to the following formula: Rs=10 -9 ×P m / h s 2 , Where, P m is the maximum load of the compressed elastic section of the polyurethane foam material, in N; h s is the elastic recovery displacement of the polyurethane foam material in the direction of the compressive load, in m; The maximum load of the compression elastic section is obtained by testing according to the method described in GB / T 8813-2008; The test method for elastic recovery displacement in the direction of compression load includes: performing compression test according to the method described in ASTM D 3574-08, with a maximum compression ratio of 75%, and the thickness of the sample after compression is recorded as h1; then the sample is placed at room temperature for 2 hours, and the thickness of the sample is measured again, which is recorded as h2; h is obtained by subtracting h2 from h1. s ; The polyurethane foam material is prepared by the following preparation method: injecting a foamable polyurethane composition into a mold and curing the polyurethane foam material to obtain the polyurethane foam material; wherein the mold includes a first mold body and a second mold body, the first mold body is located below the second mold body, the inner surface of the first mold body is preheated to 20-30°C, and the inner surface of the second mold body is preheated to 50-60°C; The foamable polyurethane composition comprises a polyol composition and an isocyanate; the polyol composition comprises a first polyol, a second polyol, a flame retardant, a chain extender, a cross-linking agent and a foaming agent; The first polyol has a hydroxyl value of 300-500 mgKOH / g and a functionality of 3-5; the second polyol has a hydroxyl value of 20-112 mgKOH / g and a functionality of 2-3; the weight ratio of the first polyol to the second polyol is (4:1)-(1:1); The content of the flame retardant is 15%-30% of the total weight of the first polyol, the second polyol and the flame retardant, the content of the chain extender is 1%-10% of the total weight of the first polyol, the second polyol and the flame retardant, the content of the cross-linking agent is 1%-5% of the total weight of the first polyol, the second polyol and the flame retardant, and the content of the foaming agent is 20%-31% of the total weight of the first polyol, the second polyol and the flame retardant.

2. The polyurethane foam material according to claim 1, wherein The elasticity ratio of the polyurethane foam material is b>-0.3 and b<0.5, and the elasticity ratio b is calculated according to the following formula: ， Wherein, ε1 is the elastic deformation rate of the polyurethane foam material, and ε2 is the plastic deformation rate of the polyurethane foam material. ε1 and ε2 are obtained by performing a tensile test according to the method described in ASTM D 3574-08.

3. The polyurethane foam material according to claim 1, wherein The hardness of the first surface is greater than that of the second surface, and a difference in Shore C hardness between the first surface and the second surface is greater than 5.

4. The polyurethane foam material according to claim 1, wherein The surface roughness of the first surface is greater than the surface roughness of the second surface, and the difference between the surface roughness of the first surface and the surface roughness of the second surface is greater than 0.2 μm.

5. The polyurethane foam material according to claim 1, wherein The fire protection grade of the polyurethane foam material is UL94-V0. The polyurethane foam material according to claim 1 , wherein: The density of the polyurethane foam material is 150-400 kg / m 3 .

7. The polyurethane foam material according to claim 1, wherein The thermal conductivity of the polyurethane foam material is ≤0.04 W / (m·K) when tested according to the method described in GB / T 10295-2008.

8. The polyurethane foam material according to claim 1, wherein The elongation at break of the polyurethane foam material is 10%-40% when tested according to the method described in ASTM D 3574-08.

9. The polyurethane foam material according to claim 1, wherein The tensile strength of the polyurethane foam material is ≥3 MPa when tested according to the method described in ASTM D 3574-08.

10. The polyurethane foam material according to claim 1, wherein The polyurethane foam material is in sheet form and has a thickness of 3-20 mm.

11. The polyurethane foam material according to claim 1, wherein The polyurethane foam material meets the following conditions: when subjected to a bending strength test according to the method described in GB / T 8812.2-2007, it does not break under a deformation of 5%.

12. The polyurethane foam material according to claim 1, wherein The stone chip resistance of the second surface of the polyurethane foam material tested according to the method described in ISO20567-1-2017 is ≤ level 1.

13. A method for preparing the polyurethane foam material according to any one of claims 1 to 12, comprising the following steps: The foamable polyurethane composition is injected into a mold and cured to obtain the polyurethane foam material; wherein the mold includes a first mold body and a second mold body, the first mold body is located below the second mold body, the inner surface of the first mold body is preheated to 20-30°C, and the inner surface of the second mold body is preheated to 50-60°C.

14. The preparation method according to claim 13, wherein The surface of the polyurethane foam material formed by contacting the first mold body is a first surface, and the surface of the polyurethane foam material formed by contacting the second mold body is a second surface.

15. A battery pack comprising: A box body comprising an upper shell and a lower shell, a battery module contained between the upper shell and the lower shell, and a polyurethane foam material provided on the side and / or bottom of the box body, wherein the polyurethane foam material is the polyurethane foam material according to any one of claims 1 to 12; The first surface of the polyurethane foam material is the surface in contact with the side and / or bottom of the box body, and the second surface of the polyurethane foam material is the surface of the battery pack exposed to the outside.

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