Polyurethane foam material, preparation method thereof and battery pack

Abstract

The invention discloses a polyurethane foam material, a preparation method thereof and a battery pack, and belongs to the technical field of polyurethane foam materials. The recovery resistance Rs of the polyurethane foam material has the following ranges: 2GPa < = Rs < = 20Gpa; the recovery resistance Rs is calculated according to the following formula: Rs = 10 <-9 > * Pm / hs2; in the formula, Pm is the maximum load of the compression elastic section of the polyurethane foam material, and the unit is N; hs is the elastic recovery displacement of the polyurethane foam material in the compression load direction, and the unit is m. The polyurethane foam material disclosed by the invention has relatively high strength and relatively high toughness, has thermal insulation performance and is suitable for being applied to the battery pack.

Description

Technical Field

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

[0002] With the rapid development of new energy electric vehicles, the safety requirements for electric vehicles are also getting higher and higher. As the power source of new energy vehicles, the importance of the safety of the power battery pack is self-evident. In new energy vehicles, the battery pack is generally located under the vehicle chassis and is connected to the chassis by bolts. The lower surface of the battery pack is exposed. During daily driving, flying and hitting of stones at the bottom may cause deformation or rupture of the battery pack housing, and then the battery cells are exposed, leading to accidents.

[0003] New energy vehicles usually use lead-acid batteries, nickel-metal hydride batteries, lithium batteries, etc. as power sources. Taking the currently common lithium battery as an example, the optimal temperature range for its operation is -20°C to 60°C. Under conditions lower than this temperature range, the cruising range of the battery will be significantly reduced. Moreover, in cold climate regions or in winter environments, when the battery is in a non-operating state, as the non-operating time increases, the heat loss of the battery pack will increase, thus affecting the battery life. This may cause the vehicle to fail to start or require more time to start.

[0004] Currently, 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, and there is a possibility that the material is broken when a stone impacts the surface of the polyurethane foam material. If the toughness of the polyurethane foam material is increased, its strength usually needs to be reduced. Then, when applied to the battery pack, due to the reduction of the strength of the polyurethane foam material, the deformation of the material will increase under the same force, and then the housing of the battery pack will be deformed. Summary of the Invention

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

[0006] To achieve the above purpose, in the first aspect of the present invention, a polyurethane foam material is provided. The polyurethane foam material includes a first surface and a second surface in the thickness direction; the recovery resistance Rs of the polyurethane foam material has 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] Wherein, P m is the maximum load of the compression elastic section of the polyurethane foam material, with the unit of N;

[0010] h s is the elastic recovery displacement in the compression load direction of the polyurethane foam material, with the unit of 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 the elastic recovery displacement in the compression load direction includes: performing a 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 denoted as h 1 ; then placing the sample at room temperature for 2 h, and measuring the thickness of the sample again, denoted as h 2 ; through h 2 -h 1 to obtain h s .

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

[0014] ,

[0015] Wherein, ε 1 is the deformation rate of the elastic deformation of the polyurethane foam material, ε 2 is the deformation rate of the plastic deformation of the polyurethane foam material, ε 1 and ε 2 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 hardness C between the first surface and the second surface is 5 or more.

[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 in surface roughness between the first surface and the second surface is 0.2 μm or more.

[0018] According to a specific embodiment of the present invention, preferably, the fire rating 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 tested to be ≤0.04 W / (m·K) according to the method described in GB / T 10295-2008.

[0021] According to a specific embodiment of the present invention, preferably, the elongation at break of the polyurethane foam material is tested to be 10%-40% 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 tested to be ≥3 MPa 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 condition: when tested for flexural strength according to the method described in GB / T 8812.2-2007, no fracture occurs under the condition of 5% deformation.

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

[0026] The second aspect of the present invention provides a preparation method of the above-mentioned polyurethane foam material, which includes the following steps:

[0027] Inject the foaming polyurethane composition into a mold, and after curing, 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 that contacts the first mold body to form is the first surface, and the surface of the polyurethane foam material that contacts the second mold body to form is the second surface.

[0029] The third aspect of the present invention provides a battery pack, which includes:

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

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

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

[0033] The polyurethane foam material of the present invention has high strength and high toughness at the same time, so it has good anti-stone impact deformation performance, and also has ideal effects in terms of flame retardancy, fire prevention and heat preservation performance. The polyurethane foam material of the present invention is suitable for application in the battery pack of new energy vehicles, playing a role in support, buffering and heat preservation, and improving the safety and stability during vehicle operation. Detailed implementation manners

[0034] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the present invention will be described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention.

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

[0036] All kinds of raw materials, reagents, instruments and equipment used in the present invention, unless otherwise specifically stated, can be obtained through market purchase or can be prepared by existing methods.

[0037] It should be understood that the terms "include", "comprise" and / or "contain" when used herein specify the presence of the stated features, integers, steps, components or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, components or combinations thereof.

[0038] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0039] <Polyurethane foam material>

[0040] According to the specific embodiments of the present invention, the present invention provides a polyurethane foam material, which includes a first surface and a second surface in the thickness direction (i.e., two surfaces perpendicular or nearly perpendicular to the thickness); the 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, etc.; 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] wherein, P m is the maximum load of the compression elastic section of the polyurethane foam material, with the unit of N;

[0044] h s is the elastic recovery displacement in the compression load direction of the polyurethane foam material, with the unit of 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 the elastic recovery displacement in the compression load direction includes: performing a compression test according to the method described in ASTM D 3574 - 08, with a maximum compression ratio of 75% (i.e., compressed to 25% of the original thickness of the sample), measuring the thickness of the sample after compression (measuring the thickness immediately after the compression test is completed), denoted as h 1 ; then placing the sample at room temperature (i.e., 23 ± 2 °C) for 2 h, and measuring the thickness of the sample again, denoted as h 2 ; through h 2 -h 1 to obtain h s .

[0047] Specifically, the sample area used in the test of the maximum load of the compression elastic section and the test of the elastic recovery displacement in the compression load direction can be about 50×50 mm, and the thickness can be 5 mm or more; if the sample thickness is less than 5 mm, multiple samples are stacked to reach a thickness of 5 mm or more. The thickness of the sample can be measured using a vernier caliper. During this test, there is no special restriction on the orientation of the first surface and the second surface. In the specific tests of the following embodiments, the second surface faces upward. The instrument specifically used in this test can be a UTM6104 electronic universal testing machine. Among them, the compression force within the proportional limit (there is an obvious straight line part in the force-displacement curve) (i.e., Fe) tested according to the method described in GB / T 8813-2008 is the maximum load of the compression elastic section. The compression test is carried out according to TEST D according to the method described in ASTM D 3574-08. Before the test, the sample is conditioned under the conditions of temperature (23±2)°C and relative humidity (50±5)%.

[0048] Generally, the strength and toughness of polyurethane foam materials are negatively correlated. Through the research of the present inventors, it is found that by controlling the recovery resistance Rs within 2 GPa ≤ Rs ≤ 20 GPa, the polyurethane foam material has both high strength and high toughness, and thus has excellent anti-stone impact deformation performance. In this way, it can avoid being broken by flying stones and also avoid damage to the battery pack box due to excessive deformation of the material under stress. If Rs is greater than 20 GPa, 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 broken. If Rs is less than 2 GPa, the strength of the polyurethane foam material is insufficient. When applied to the battery pack, under external force, the material is prone to excessive deformation, resulting in damage to the battery pack box.

[0049] In some embodiments, the elastic ratio b of the polyurethane foam material satisfies -0.3 < b < 0.5. For example, the elastic 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, etc. The elastic ratio b is calculated according to the following formula:

[0050] ,

[0051] In the formula, ε 1 is the deformation rate of the elastic deformation of the polyurethane foam material, and ε 2 is the deformation rate of the plastic deformation of the polyurethane foam material, and ε 1 and ε 2The tensile test was performed according to the method described in ASTM D 3574-08.

[0052] Specifically, the tensile test according to the method described in ASTM D 3574-08 is carried out according to TEST E. The sample used in the test is dumbbell-shaped (it can be made by a special-shaped mold, as long as the inner surface temperature of the first mold body and the second mold body of the mold is kept within the range of the present invention; or it can also be made by cutting the sample), the size is as described in FIG.1 of TEST E, and the thickness is the thickness of the sample prepared in the following embodiment. The rising direction of the test is the length direction of the sample (i.e., longitudinal stretching), and the test speed is (500±5) mm / min. The specific instrument used in this test can be a UTM6104 electronic universal testing machine. ε 1 and ε 2 It is obtained through the SUNS-FY-2000 software that comes with the instrument. Generally speaking, elastic deformation reflects the toughness of the material. Materials with large elastic deformation can maintain good shape stability when subjected to impact or pressure, thereby avoiding fracture. Plastic deformation reflects the ability of a material to stably undergo permanent deformation under the action of external forces without destroying its integrity. The inventors have found through research that when the elasticity ratio b>-0.3 and b<0.5, it is conducive to synergizing with the recovery resistance Rs, further making the material 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 hardness C between the first surface and the second surface is 5 or more. By further controlling that the hardness of the first surface is greater than that of the second surface and controlling the difference therebetween within the above range, the present invention further facilitates the material to have both high strength and high toughness, and can better block the impact force and avoid excessive deformation when impacted by stones, further enabling the polyurethane foam material to have good anti-stone-impact deformation performance. Specifically, the softer second surface absorbs the instantaneous impact energy, and the impact force is gradually transmitted to the harder first surface. By controlling the hardness difference within the above range, the low-frequency vibration and residual stress during the transmission of the impact force are fully eliminated, so that the impact force can be better blocked; and the softer second surface can reduce the rebound rate of the impact force, while the harder first surface can provide support, thus avoiding excessive deformation of the material. Preferably, the Shore hardness C of the first surface is 90-98, and the Shore hardness C of the second surface is 82-90. The Shore hardness C of both surfaces of the polyurethane foam material of the present invention is 80 or more, belonging to rigid polyurethane foam materials. The Shore hardness C is measured according to the method described in ASTM D2240-05(2010). If the Shore hardness C of the first surface and the second surface is lower than the above range, the polyurethane foam material is too soft, resulting in insufficient strength of the material. If the Shore hardness C of the first surface and the second surface is higher than the above range, the polyurethane foam material is too hard, resulting in poor toughness of the material.

[0054] In some embodiments, the surface roughness of the first surface is greater than that of the second surface, and the difference in surface roughness between the first surface and the second surface is 0.2 μm or more. By further controlling that the surface roughness of the first surface is greater than that of the second surface and controlling the difference therebetween within the above range, the present invention further facilitates the material to have both high strength and high toughness. The surface roughness (R z)(0) is obtained by testing according to the method described in ISO4287-1997. 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 enables the first surface to have high bonding performance, and when using an adhesive to assemble the polyurethane foam material with the box body, a better fitting effect can be obtained; at the same time, due to controlling the roughness range of the first surface, the first surface has a suitable micro-concave and convex structure, and these concave and convex structures are beneficial to dispersing external forces, thereby further facilitating the polyurethane foam material to have high strength. If the roughness of the first surface is lower than the above range, the bonding performance and strength of the polyurethane foam material are insufficient; if the roughness of the first surface is higher than the above range, the polyurethane foam material is likely to scratch the box body and excessively squeeze the box body. At the same time, by further controlling the roughness of the second surface within the above range, the present invention makes the second surface relatively smooth, so that when being impacted by stones, the stress distribution is relatively uniform, thereby further facilitating the polyurethane foam material to have high toughness and not being easily broken. 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 fire rating of the polyurethane foam material is UL94-V0. The fire rating of the polyurethane foam material is obtained by 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 , such as 150 kg / m 3 , 160 kg / m 3 , 170 kg / m 3 , 180 kg / m 3 , 190 kg / m 3 , 200 kg / m 3 , 210 kg / m 3 , 220 kg / m 3 , 230 kg / m 3 , 240 kg / m 3 , 250 kg / m 3 , 260 kg / m 3 , 270 kg / m 3 , 280 kg / m 3 , 290 kg / m 3 , 300 kg / m 3 , 310 kg / m 3 , 320 kg / m3 、 330 kg / m 3 、 340 kg / m 3 、 350 kg / m 3 、 360 kg / m 3 、 370 kg / m 3 、 380 kg / m 3 、 390 kg / m 3 or 400 kg / m 3 etc., preferably 250 - 350 kg / m 3 。 The density of the polyurethane foam material is measured by 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 by the preparation method of the specific embodiment of the present invention. When the density is in the range of 150 - 400 kg / m 3 range, it is beneficial to make the polyurethane foam material have good heat insulation performance and is beneficial to meet the Rs of the present invention. If the density is greater than the above range, the thermal conductivity coefficient of the polyurethane foam material will be too high, resulting in poor heat 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 coefficient of the polyurethane foam material is measured as ≤0.04 W / (m·K) by the method described in GB / T 10295 - 2008, such as 0.04 W / (m·K), 0.03 W / (m·K), 0.02 W / (m·K) or 0.01 W / (m·K), etc. By controlling the thermal conductivity coefficient within the above range, the present invention enables the polyurethane foam material to have good heat insulation performance.

[0058] In some embodiments, the elongation at break of the polyurethane foam material is measured as 10% - 40% by the method described in ASTM D 3574 - 08, such as 10%, 15%, 20%, 25%, 30%, 35% or 40%, etc. By further controlling the elongation at break within the above range, the present invention further enables the polyurethane foam material to have both high strength and high toughness. If the elongation at break is greater than the above range, after the polyurethane foam material is compressed, the deformation recovery is too fast and the recovery degree is too high; at the same time, when the polyurethane foam material is stretched, excessive elastic deformation occurs; all of these result in insufficient strength of the material. If the elongation at break is less than the above range, the deformation recovery of the polyurethane foam material after being compressed is too difficult; at the same time, when the polyurethane foam material is stretched, insufficient elastic deformation can be generated; all of these result in insufficient toughness of the material.

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

[0060] In some embodiments, the polyurethane foam material is in sheet form, and its thickness is 3-20 mm, such as 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, etc.

[0061] In some embodiments, the polyurethane foam material satisfies the following conditions: the flexural strength is tested according to the method described in GB / T 8812.2-2007, and no fracture occurs under the condition of 5% deformation. Specifically, the sample is conditioned at a temperature of (23±2) °C and a relative humidity of (50±5)% before testing. The moving speed of the load indenter during the test is (20±1) mm / min. When the polyurethane foam material satisfies the above conditions, it is further beneficial for the material to have both high strength and high toughness.

[0062] In some embodiments, the stone chipping resistance rating of the second surface of the polyurethane foam material tested according to the method described in ISO 20567-1-2017 is ≤1. Specifically, the sample is clamped on a 100×100 mm test plate using a fixture, and the first surface of the sample is attached to the test plate (without adhesive) to test the stone chipping resistance of the second surface. The test plate with the clamped sample is conditioned at a temperature of (23±2) °C and a relative humidity of (50±5)% before testing. The test is carried out according to the conditions of Method A in Table 2, and the rating is divided according to the description in Figure 3. The stone chipping resistance rating of ≤1 includes Rating 0.5 (i.e., 0.5 level) and Rating 1.0 (i.e., 1 level) in Figure 3. The area of the sample used for the test can be about 100×100 mm, and the thickness is the thickness of the sample prepared in the following examples. When the stone chipping resistance rating of the second surface is greater than 1, when being impacted by stones, slight dents or pits may appear on the side and / or bottom of the box body in contact with the polyurethane foam material, and even cracks and other damaged conditions may occur.

[0063] <Foaming Polyurethane Composition>

[0064] In some embodiments, the foaming polyurethane composition of the present invention comprises a polyol composition and an isocyanate.

[0065] (polyol)

[0066] In some embodiments, the polyol composition comprises 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). For the two polyols used in the present invention, due to the differences in hydroxyl value and functionality, there are certain differences in their reactivity. Specifically, the first polyol has a higher hydroxyl value and functionality, and thus a higher reactivity; the second polyol has a lower hydroxyl value and functionality, and thus a lower reactivity. During the reaction process, in molecular chains of the same length, if the content of the first polyol is too high, the content of the isocyanate will also be too high, and the polyurethane foam material mainly uses isocyanate segments as hard segments to provide hardness. When the content of the first polyol is too high, there are too many hard segments in the molecular chains of the polyurethane foam material, resulting in an excessive Rs. On the contrary, if the content of the second polyol is too high, Rs will be too small.

[0068] According to specific embodiments of the present invention, by using the above-mentioned first polyol and second polyol and their ratio range, it is beneficial to keep the recovery resistance Rs of the polyurethane foam material within the above-mentioned range of the present invention.

[0069] In some embodiments, as the first polyol, for example but not limited to: one or more of sucrose polyether polyol, castor oil-based polyether polyol, sorbitol polyether polyol, etc. Specifically, for example but not limited to: 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), WANOL® R2490 (hydroxyl value 490 mgKOH / g, functionality 3), etc.

[0070] In some embodiments, as the second polyol, for example but not limited to: one or more of polymer polyol, propylene glycol polyether polyol, tetrahydrofuran polyether polyol, etc. Specifically, for example but not limited to: at least one of VORANOL4701 (hydroxyl value 34mgKOH / g, functionality 3), NJ-330N (hydroxyl value 34mgKOH / g, functionality 3), NJ-360 (hydroxyl value 28mgKOH / g, functionality 3), NJ-3628 (hydroxyl value 28mgKOH / g, functionality 3), NJ-210 (hydroxyl value 112mgKOH / g, functionality 2), CHP-H45 (hydroxyl value 21mgKOH / g, functionality 3), etc.

[0071] (Flame retardant)

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

[0073] In some embodiments, the content of the flame retardant is 15%-30% of the total weight of the first polyol, the second polyol and the flame retardant.

[0074] In some embodiments, as the flame retardant, for example but not limited to: one or more of tris(1-chloro-2-propyl) phosphate, tris(1,3-dichloroisopropyl) phosphate, tris(2-chloroethyl) phosphate, dimethyl methylphosphonate, diethyl ethylphosphonate, 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 methylphosphonate and diethyl ethylphosphonate.

[0075] According to specific embodiments of the present invention, by using a flame retardant, the polyurethane foam material can have better flame retardant properties, and at the same time can improve the fluidity of the foaming polyurethane composition, thereby making the polyurethane foam material have a more ideal appearance. However, if the content of the flame retardant is higher than the above range, the toughness of the polyurethane foam material will be too low. When the content of the flame retardant is within the above range, it is beneficial for the polyurethane foam material to have a UL94-V0 fire rating and also have an Rs within the above 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% of the total weight of the first polyol, the second polyol and the flame retardant, preferably 3%-10%.

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

[0080] According to the specific embodiments of the present invention, by using a chain extender, the molecular weight of the polyurethane foam material can be increased, short - chain molecules can be changed into long - chain molecules, and thus it is beneficial for the polyurethane foam material to have 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 cross - linking agent is 1% - 5% of the total weight of the first polyol, the second polyol and the flame retardant, preferably 1% - 3%. If the dosage of the cross - linking agent is higher than the above - mentioned range, there will be too many hard segments in the molecular chains of the polyurethane foam material, resulting in too large P m being too large, thus leading to too large Rs. On the contrary, if the dosage of the cross - linking agent is lower than the above - mentioned range, the Rs of the material will be too small. When the content of the cross - linking agent is within the above - mentioned range, it is beneficial for the polyurethane foam material to have Rs within the above - mentioned range of the present invention.

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

[0085] (Foaming agent)

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

[0087] In some embodiments, the content of the foaming 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 content of water is 0.15% - 0.7% of the total weight of the first polyol, the second polyol and the flame retardant, and more preferably 0.15% - 0.5%.

[0089] In some embodiments, the physical blowing agent includes a first blowing agent and a second blowing agent. The first blowing agent is selected from at least one of alkanes and fluorohydrocarbons, and the second blowing agent is selected from at least one of carbonates. As the first blowing agent, for example but not limited to: one or more of 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane, n-pentane, cyclopentane, etc. As the second blowing agent, for example but not limited to: one or more of sodium bicarbonate, ammonium carbonate, and magnesium carbonate, etc.

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

[0091] According to specific embodiments of the present invention, by using a combination of two physical blowing agents and water as the blowing agent, the polyurea formed after the reaction of water and isocyanate can be reduced, which is beneficial to making the polyurethane foam material have an Rs within the above range of the present invention.

[0092] (Catalyst)

[0093] In some embodiments, the polyol-containing composition further includes 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, as the catalyst, it can be selected from at least one of amine catalysts and organometallic catalysts. For example 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 also selectively include other functional additives. As other functional additives, for example but not limited to: one or more of foam stabilizers (such as but not limited to silicone oil), antioxidants, antistatic agents, colorants, hydrolysis-resistant agents, etc. The content of these other functional additives can be adjusted conventionally by those skilled in the art, and the present invention does not impose special restrictions on it.

[0098] (Isocyanate)

[0099] In some embodiments, as the isocyanate, for example but not limited to: toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, liquefied diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, etc., one or more than two of them. Preferably, the isocyanate is selected from one or more than two of diphenylmethane diisocyanate, liquefied diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, etc. According to the specific embodiments of the present invention, by preferably using a straight-chain and / or lower functionality isocyanate, it is beneficial to make the polyurethane foam material have Rs within the above range of the present invention.

[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 dosage of the isocyanate is too much, there will be too many hard segments in the molecular chain of the polyurethane foam material, resulting in too large P m being too large, thus resulting in too large Rs. On the contrary, if the dosage of the isocyanate is too small, the Rs of the material will be too small. When the dosage of the isocyanate is within the above range, it is beneficial to make the polyurethane foam material have Rs within the above range of the present invention.

[0101] <Preparation method of polyurethane foam material>

[0102] According to the specific implementation manner of the present invention, the present invention provides a preparation method of a polyurethane foam material, which includes the following steps:

[0103] Inject the foaming polyurethane composition into a mold, and after curing (reacting and foaming during the curing process), 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 chambers. During use, the edges of the first mold body and the second mold body are in contact and connected, and the chambers of the first mold body and the second mold body communicate to form a shaping cavity. The shaping cavity can be a regular cube or an irregular special shape. The size of the plastic cavity is preferably: the area is 10 mm × 10 mm to 1000 mm × 1000 mm, and the thickness is 3 - 20 mm. It should be noted that the thickness of the shaping cavity is the thickness of the prepared polyurethane foam material, so this 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: before injecting the foaming polyurethane composition into the mold, a release agent is sprayed on the inner surfaces of the first mold body and the second mold body. The release agent can be a conventional release agent in the art, and the present invention does not impose special restrictions on it.

[0106] According to specific embodiments of the present invention, when the inner surface temperatures of the first mold body and the second mold body are within the above ranges, the molecular chain movement rates on the two surfaces of the foaming polyurethane composition during the foaming process are different. When injected into the first mold body located below, the molecular chains move slower, generating residual stress or phase change, while the molecular chains on the side in contact with the second mold body move faster. Thus, it is beneficial to meet the Rs of the present invention, beneficial to endow the surface of the polyurethane foam material in contact with the first mold body with excellent strength, and at the same time beneficial to endow the surface of the polyurethane foam material in contact with the second mold body with excellent toughness, and further beneficial to have both high strength and high toughness.

[0107] Moreover, when the foaming polyurethane composition is injected into the first mold body located below, since the reaction rate is slowed down, the fluidity of the foaming polyurethane composition can be increased, and thus it can better fill the cavity of the mold, reducing the occurrence of defects such as air bubbles and material shortage during the preparation process. And, it can eliminate the problem of color difference in the feeding line caused by the asynchronous reaction due to the part of the foaming polyurethane composition that first contacts the mold body with too high temperature reacting too fast when the foaming polyurethane composition is injected into a mold with an inner surface temperature higher than the above range of the first mold body.

[0108] Meanwhile, when the inner surface temperature of the first mold body is within the above range, the evaporation rate of the release agent is slower when spraying the release agent, resulting in a lower packing density after the release agent has completely evaporated, and the surface roughness of the first mold body after spraying the release agent is increased compared to the surface of the mold body with a mold temperature higher than the above range. Correspondingly, it is beneficial to form a relatively rough first surface on the polyurethane foam material. And, if the inner surface temperature of the first mold body is higher than the above range, the movement speed of the release agent molecules is too fast, and more release agent is transferred to the material when the polyurethane foam material is demolded after production. Therefore, in the present invention, when the inner surface temperature of the first mold body is within the above range, it is beneficial to make the formed first surface have less release agent residue and have the surface roughness within the above range of the present invention. And, when the inner surface temperature of the second mold body is within the above range, it is beneficial to make the formed second surface have the surface roughness within the above range of the present invention.

[0109] In some embodiments, before injecting the foaming polyurethane composition into a mold, the preparation method further comprises the following steps: sequentially performing a first mixing, a second mixing, and a third mixing on a polyol composition and an isocyanate to obtain a foaming polyurethane composition; the first mixing is carried out at 35-40 °C under stirring conditions, the stirring speed of the first mixing is above 60 r / min, and the time of the first mixing is above 30 min; 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 time of the second mixing is above 5 s; the third mixing is carried out in a static mixer. Specifically, the length of the static mixer is above 20 cm.

[0110] According to a specific embodiment of the present invention, before injecting the foaming polyurethane composition into a mold, three mixings are carried out. When the conditions of the three mixings are within the above ranges, the foaming polyurethane composition injected into the mold forms shish-kebab crystals during crystallization, which is beneficial for the polyurethane foam material to have Rs within the above ranges of the present invention.

[0111] In some embodiments, the thicknesses 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 min, preferably 8-12 min.

[0113] In some embodiments, the preparation method of the polyurethane foam material may specifically comprise the following steps:

[0114] (1) Mixing a first polyol, a second polyol, a flame retardant, a chain extender, a crosslinking agent, a catalyst, other functional additives selectively added, and a blowing agent uniformly to obtain a polyol composition (Component A);

[0115] (2) Performing a first mixing on the polyol composition (Component A) and an isocyanate (Component B) at 35-40 °C under stirring conditions, the stirring speed of the first mixing is above 60 r / min, the time of the first mixing is above 30 min, then performing a second mixing at 28-32 °C under stirring conditions, the stirring speed of the second mixing is 5000-8000 r / min, the time of the second mixing is above 5 s, and then performing a third mixing through a static mixer to obtain a foaming polyurethane composition;

[0116] (3) Inject the foaming polyurethane composition into a mold, and after curing, 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.

[0117] <Application>

[0118] The polyurethane foam material of the present invention has both high strength and high toughness, and also has ideal effects in terms of flame retardancy and heat insulation performance, and can be applied to various fields of support materials, buffer materials and heat insulation materials, such as but not limited to being applied to battery packs. Specifically, the polyurethane foam material of the present invention is particularly suitable for being applied to new energy power battery packs.

[0119] According to the specific embodiments of the present invention, the present invention provides a battery pack, which includes:

[0120] A box body including an upper shell and a lower shell, a battery module contained between the upper shell and the lower shell, and a polyurethane foam material disposed 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 outside.

[0121] The polyurethane foam material of the present invention is suitable for being applied to the battery packs of new energy vehicles, plays a role in support, buffering and heat insulation, has excellent anti-stone impact deformation performance, and can improve the safety and stability during the operation of the vehicle.

[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 of course, various deformations can be carried out within the scope of the key points of the present invention.

[0124] Example 1

[0125] By weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 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 part of water, 1 part of silicone oil, and 0.5 part of N,N-dimethylcyclohexylamine were added to a high-speed mixer for mixing to obtain Component A (i.e., the polyol-containing composition); 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:75 (stirred at a speed of 80 r / min for 30 min in a storage tank at 35°C), second mixed (flowed through a mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, with a residence time in the mixing chamber of more than 5 s and a temperature of 30°C), and third mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming polyurethane composition was injected into a mold, which included a second mold body (i.e., the upper mold body) with a thickness of 5 mm and a first mold body (i.e., the lower 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0126] Example 2

[0127] By weight, 30 parts of NJ-3628, 60 parts of NJ-6305B, 20 parts of diethyl ethylphosphonate, 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 part of water, 1 part of silicone oil, and 0.4 part of triethylenediamine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in sequence at a mass ratio of 100:100 (stirred at a speed of 80 r / min for 30 min in a feed tank at 35 °C), second mixed (flowed through a mixing chamber at the injection head at a stirring speed of 8000 r / min, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C), and third mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0128] Example 3

[0129] 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 part of water, 0.9 part of silicone oil, and 0.5 part of N-methylmorpholine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:65 (stirred at 80 r / min for 30 min in a feed tank at 35°C), second mixed (flowed through a mixing chamber in the injection head at a stirring speed of 8000 r / min for a time of more than 5 s and at a temperature of 30°C), and third mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0130] Example 4

[0131] 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 part of water, 1 part of silicone oil, and 0.5 part of dimethylaminoethanol were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:90 (stirred at 80 r / min for 30 min in a feed tank at 35 °C), second mixed (flowed through a mixing chamber in the injection head at a stirring speed of 8000 r / min, with a residence time in the mixing chamber of more than 5 s and a temperature of 30 °C), and third mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming 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 60 °C and the inner surface of the first mold body was preheated to 20 °C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0132] Example 5

[0133] By weight, 16 parts of VORANOL 4701, 64 parts of A-30, 20 parts of dimethyl methylphosphonate, 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 part of water, 0.5 part of silicone oil, and 0.1 part of imidazole were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:80 (stirred at a speed of 80 r / min for 30 min at 35 °C in a feed tank), second mixed (flowed through a mixing chamber at the injection head at a stirring speed of 8000 r / min, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C), and third mixed (mixed by flowing through a static mixer with a length of 25 cm) to obtain a foaming polyurethane composition; the foaming 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 50 °C, and the inner surface of the first mold body was preheated to 30 °C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0134] Example 6

[0135] By weight, 40 parts of VORANOL 4701, 40 parts of A-30, 20 parts of dimethyl methylphosphonate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 18 parts of cyclopentane, 6 parts of sodium bicarbonate, 0.5 part of water, 0.5 part of silicone oil, and 0.1 part of stannous octoate were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:70 (stirred at a speed of 80 r / min for 30 min at 35 °C in a feed tank), second mixed (flowed through a mixing chamber at the injection head at a stirring speed of 8000 r / min, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C), and third mixed (mixed by flowing through a static mixer with a length of 25 cm) to obtain a foaming polyurethane composition; the foaming 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 50 °C, and the inner surface of the first mold body was preheated to 30 °C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0136] Example 7

[0137] By weight, 40 parts of PURANOL RF3777M, 40 parts of NJ210, 20 parts of dimethyl methylphosphonate, 3 parts of ethylene glycol, 1 part of diethanolamine, 15 parts of n-pentane, 5 parts of magnesium carbonate, 0.5 part of water, 0.5 part of silicone oil, and 0.1 part of stannous octoate were added to a high-speed mixer for mixing to obtain Component A; 100 parts of diphenylmethane diisocyanate was used as Component B; Component A and Component B were successively subjected to the first mixing (stirring at a speed of 80 r / min for 30 min at 35 °C in a feed tank), the second mixing (flowing through a mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, with the residence time in the mixing chamber being more than 5 s and the temperature being 30 °C), and the third mixing (mixing by flowing through a static mixer with a length of 25 cm) in a mass ratio of 100:60 to obtain a foaming polyurethane composition; the foaming 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 50 °C, and the inner surface of the first mold body was preheated to 30 °C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0138] Example 8

[0139] By weight, 60 parts of WANOL® R2490, 15 parts of CHP-H45, 20 parts of dimethyl methylphosphonate, 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 part of water, 0.5 part of silicone oil, and 0.1 part of stannous octoate were added to a high-speed mixer for mixing to obtain Component A; 100 parts of hexamethylene diisocyanate was used as Component B; Component A and Component B were successively subjected to the first mixing (stirring at a speed of 80 r / min for 30 min at 35 °C in a feed tank), the second mixing (flowing through a mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, with the residence time in the mixing chamber being more than 5 s and the temperature being 30 °C), and the third mixing (mixing by flowing through a static mixer with a length of 25 cm) in a mass ratio of 100:100 to obtain a foaming polyurethane composition; the foaming 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 50 °C, and the inner surface of the first mold body was preheated to 30 °C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0140] Comparative Example 1

[0141] By weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 5 parts of ethylene glycol, 2 parts of diethanolamine, 1.4 parts of water, 1 part of silicone oil, and 0.5 part of N,N-dimethylcyclohexylamine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:90 (stirred at 80 r / min for 30 min in a feed tank at 35°C), secondarily mixed (flowed through a mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, with a residence time in the mixing chamber of more than 5 s and a temperature of 30°C), and thirdly mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0142] Comparative Example 2

[0143] By weight, 40 parts of NJ-330N, 50 parts of NJ-4110, 10 parts of dimethyl methylphosphonate, 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 part of water, 1 part of silicone oil, and 0.5 part of N,N-dimethylcyclohexylamine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:70 (stirred at a speed of 80 r / min for 30 min in a feed tank at 35°C), second mixed (flowed through a mixing chamber in the injection head at a stirring speed of 8000 r / min, with a residence time in the mixing chamber of more than 5 s and a temperature of 30°C), and third mixed (flowed through a static mixer with a length of 25 cm for mixing) to obtain a foaming polyurethane composition; the foaming 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 55°C. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0144] Comparative Example 3

[0145] By weight, 40 parts of NJ-330N, 40 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 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 mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were mixed successively in a mass ratio of 100:90 for the first time (stirred at a speed of 80 r / min for 30 min in a feed tank at 35 °C), the second time (flowed through a mixing chamber at the injection head at a stirring speed of 8000 r / min, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C), and the third time (mixed by flowing through a static mixer with a length of 25 cm) to obtain a foaming polyurethane composition; the foaming 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. And before injecting the foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0146] Comparative Example 4

[0147] By weight, 80 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 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 mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were mixed successively in a mass ratio of 100:110 for the first time (stirred at a speed of 80 r / min for 30 min in a feed tank at 35 °C), the second time (flowed through a mixing chamber at the injection head at a stirring speed of 8000 r / min, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C), and the third time (mixed by flowing through a static mixer with a length of 25 cm) to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0148] Comparative Example 5

[0149] By weight, 60 parts of NJ-330N, 20 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 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 part of water, 0.5 part of silicone oil, and 0.5 part of N,N-dimethylcyclohexylamine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were first mixed in a mass ratio of 100:45 (stirred at a speed of 80 r / min for 30 min in a feed tank at 35°C), second mixed (flowed through a mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, the residence time in the mixing chamber was more than 5 s, and the temperature was 30°C), and third mixed (mixed by flowing through a static mixer with a length of 25 cm) to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

[0150] Comparative Example 6

[0151] By weight, 30 parts of NJ-330N, 60 parts of NJ-4110, 20 parts of dimethyl methylphosphonate, 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 part of water, 1 part of silicone oil, and 0.5 part of N,N-dimethylcyclohexylamine were added to a high-speed mixer for mixing to obtain Component A; 80 parts of polymeric diphenylmethane diisocyanate and 20 parts of liquefied diphenylmethane diisocyanate were added to a high-speed mixer for mixing to obtain Component B; Component A and Component B were mixed only once at a mass ratio of 100:95 (i.e., the second mixing in the above examples), that is, they flowed through the mixing chamber at a stirring speed of 8000 r / min in the mixing chamber of the injection head, the residence time in the mixing chamber was more than 5 s, and the temperature was 30 °C to obtain a foaming polyurethane composition; the foaming 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 foaming polyurethane composition, a mold release agent 631 was sprayed on the inner surfaces of both the first mold body and the second mold body. After curing for 10 min, it was taken out to obtain a polyurethane foam material.

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

[0153] Table 1 Characteristics of the Examples

[0154]

[0155] Table 2 Characteristics of the Comparative Examples

[0156]

[0157] As can be seen from Table 1 and Table 2, in each example of the present invention, by controlling the recovery resistance Rs at 2 GPa ≤ Rs ≤ 20 GPa, the polyurethane foam material has both high strength and high toughness, and thus has excellent anti-stone impact deformation performance, can avoid being broken 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 each comparative example is not within the range controlled by the present invention, and the polyurethane foam materials of each comparative example are either insufficient in flexural strength, or insufficient in anti-stone impact grade, or both insufficient in flexural strength and anti-stone impact grade, and do not have excellent anti-stone impact deformation performance.

Claims

1. A polyurethane foam material, wherein: The polyurethane foam material comprises a first surface and a second surface in a thickness direction; 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 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 compression 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 of 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 placing the sample at room temperature for 2 hours, and measuring the thickness of the sample again, which is recorded as h2; and obtaining h by h2-h1. s .

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: ， In the formula, ε1 is the deformation rate of elastic deformation of the polyurethane foam material, ε2 is the deformation rate of plastic deformation of the polyurethane foam material, and 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.

6. 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 a bending strength test is conducted according to the method described in GB / T 8812.2-2007, no fracture occurs under a deformation of 5%.

12. The polyurethane foam material according to claim 1, wherein The stone impact resistance level 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 after curing, the polyurethane foam material is obtained; 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 arranged 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 a surface that is in contact with the side surface and / or the bottom of the box body, and the second surface of the polyurethane foam material is a surface of the battery pack that is exposed to the outside.

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