Silica gel foam

Abstract

The invention discloses silica gel foam, and belongs to the technical field of silica gel foam materials. In the Fourier transform infrared spectrum of the silica gel foam, the absolute value of the difference between the absorbance of a first characteristic peak and the absorbance of a second characteristic peak is 0.02 or above, the first characteristic peak is located at the wave number of 861-865 cm <-1 >, and the second characteristic peak is located at the wave number of 910-920 cm <-1 >; before and after the silica gel foam is placed in an environment of 180 DEG C for 4 hours, in a Fourier transform infrared spectrum of the silica gel foam, the attenuation rate of absorbance at a wave number of 1082 cm <-1 > is less than or equal to 3%. The silica gel foam provided by the invention has both low gas release property and low rebound loss property, is suitable for being applied to a new energy battery, and can play roles in buffering, waterproofing, sealing and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silica gel foam materials, in particular to a silica gel foam. BACKGROUND

[0002] New energy and rail transit industries need to use materials with good environmental tolerance and buffering performance. Using materials with certain compressive strength and good rebound performance in the battery pack is beneficial to the processing and assembly of the battery pack, and can improve the processing efficiency of the battery module in the battery pack, while avoiding the occurrence of battery pack air and water leakage.

[0003] However, most of the buffer materials currently used in battery packs have the following problems:

[0004] (1) The rebound performance of the material needs to be further improved.

[0005] Materials with poor rebound performance cannot fully rebound to provide corresponding rebound force during the maintenance of the heavy box body and after assembly, which causes the loss of sealing performance around the box body. Reduces the protective service life of the battery box itself.

[0006] (2) With the increase of use time, the material will release small molecule substances.

[0007] These small molecule substances will form a separation layer in the box body of the battery pack. The separation layer mainly refers to the aggregation of low volatile siloxane small molecule substances to form an ink layer. The separation layer will reduce the adhesion of the adhesive material and the box body, and will also penetrate into part of the insulation material, causing the insulation performance of the box body to decrease, which poses a certain safety hazard. SUMMARY

[0008] To solve the above technical problems, the purpose of the present application is to provide a silica gel foam. The silica gel foam of the present application has low outgassing and low rebound loss, and is suitable for application in new energy battery boxes, which can play a buffering, waterproof, sealing and other roles.

[0009] To achieve this purpose, the present inventors have found through repeated research that if the absolute value of the absorbance difference of the first characteristic peak at a wave number of 861-865 cm -1 and the second characteristic peak at a wave number of 910-920 cm -1 in the Fourier transform infrared (FT-IR) spectrum of the silica gel foam is controlled within a certain range, and the decay rate of the absorbance at a wave number of 1082 cm -1 in the Fourier transform infrared (FT-IR) spectrum of the silica gel foam before and after placing it in an environment of 180℃ for 4 hours is controlled within a certain range, then a silica gel foam with low outgassing and low rebound loss can be obtained.

[0010] Specifically, the present application provides a silica gel foam, in the Fourier transform infrared spectrum of which, the absolute value of the difference between the absorbance of a first characteristic peak and a second characteristic peak is 0.02 or more, the first characteristic peak is located at a wave number of 861-865 cm -1 , and the second characteristic peak is located at a wave number of 910-920 cm -1 ; the decay rate of the absorbance of the silica gel foam at 1082 cm -1 wave number before and after the silica gel foam is placed in an environment at 180℃ for 4 hours is ≤3%.

[0011] According to the specific embodiment of the present application, preferably, the 25% relative compression permanent deformation rate of the silica gel foam is 3% or less after the silica gel foam is placed in an environment at 100℃ for 24 hours in a compressed state with a compression rate of 25%, the compression is then removed, and the silica gel foam is then placed in an environment at room temperature (23±2℃) for 0.5 hours, the 25% relative compression permanent deformation rate being calculated by the following formula:

[0012] P=T2÷T1×100%,

[0013] wherein P is the 25% relative compression permanent deformation rate, %;

[0014] T2 is the difference between the thickness of the silica gel foam before compression and the thickness of the silica gel foam after the compression is removed and the silica gel foam is placed in an environment at room temperature for 0.5 hours, in mm;

[0015] T1 is the thickness of the silica gel foam before compression, in mm.

[0016] According to the specific embodiment of the present application, preferably, the 70% relative compression permanent deformation rate of the silica gel foam is 5% or less after the silica gel foam is placed in an environment at 100℃ for 24 hours in a compressed state with a compression rate of 70%, the compression is then removed, and the silica gel foam is then placed in an environment at room temperature (23±2℃) for 0.5 hours, the 70% relative compression permanent deformation rate being calculated by the following formula:

[0017] Q=R2÷R1×100%,

[0018] wherein Q is the 70% relative compression permanent deformation rate, %;

[0019] R2 is the difference between the thickness of the silica gel foam before compression and the thickness of the silica gel foam after the compression is removed and the silica gel foam is placed in an environment at room temperature for 0.5 hours, in mm;

[0020] R1 is the thickness of the silica gel foam before compression, in mm.

[0021] According to the specific embodiment of the present application, preferably, the million times compression thickness decay rate of the silica gel foam is ≤1.5%; the million times compression thickness decay rate of the silica gel foam is tested by the following method: the silica gel foam is compressed from 0 to 50% and then removed, recorded as 1 time of compression, the compression frequency is 2.5 Hz, after 1 million times of compression, the million times compression thickness decay rate is tested.

[0022] According to the specific embodiment of the present application, preferably, the silica gel foam is placed in an environment of 150℃, vacuum degree of 7×10 - 3 Pa for 24 hours, the mass loss rate (ML) thereof is ≤1%, and the mass of the collectable condensate (CV) generated accounts for ≤0.5% of the mass of the silica gel foam. More preferably, the silica gel foam is placed in an environment of 150℃, vacuum degree of 7×10 - 3 Pa for 24 hours, the mass loss rate thereof is 0.3%-0.9%, and the mass of the collectable condensate generated accounts for 0.1%-0.45% of the mass of the silica gel foam.

[0023] wherein, the mass loss rate and the mass of the collectable condensate account for the mass of the silica gel foam are tested by the following method:

[0024] The silica gel foam is pretreated by being placed in an environment of 23℃, 50% relative humidity (RH) for 24 hours to obtain pretreated silica gel foam; then the pretreated silica gel foam is placed in an environment of 150℃, vacuum degree of 7×10 -3 Pa for 24 hours, and then cooled to room temperature (23±2℃); then the silica gel foam is pressurized to normal pressure by using dry protective gas, the gas generated by the silica gel foam is condensed and collected on a pre-weighed collection plate at a constant temperature of 25℃ to obtain collectable condensate; the mass loss rate of the silica gel foam and the mass of the collectable condensate account for the mass of the silica gel foam are tested.

[0025] According to the specific embodiment of the present application, preferably, the compression resilience stress retention rate of the silica gel foam after being compressed for 1 min and 30 min under the condition of room temperature (23±2℃) and in the compression rate range of 30%-80% is all ≥80%. More preferably, the compression resilience stress retention rate of the silica gel foam after being compressed for 1 min under the condition of room temperature and in the compression rate range of 30%-80% is 90%-97%, and the compression resilience stress retention rate after being compressed for 30 min is 80%-90%.

[0026] According to the specific embodiment of the present application, preferably, the thickness change rate of the silica aerogel is ≤3%, more preferably 0.2%-3% after the silica aerogel is placed in an environment of 85℃ and 85% relative humidity (RH) for 1000 hours in a compressed state with a compression rate of 50%, then the compression is removed, and then placed in a room temperature environment (23±2℃) for 0.5 hours.

[0027] According to the specific embodiment of the present application, preferably, the 25% compression stress of the silica aerogel is 50-200kPa.

[0028] According to the specific embodiment of the present application, preferably, the density of the silica aerogel is 300-550g / m 3 .

[0029] According to the specific embodiment of the present application, preferably, the thickness of the silica aerogel is 0.5-16mm.

[0030] The present application has at least the following beneficial effects:

[0031] The silica aerogel of the present application has low outgassing property and low resilience loss property, and is suitable for application in new energy battery boxes, and can play a role in buffering, waterproofing, sealing, etc. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the present application is described in detail below, but it cannot be understood as limiting the implementable scope of the present application.

[0033] <Silica aerogel>

[0034] The present application provides a silica aerogel, in the Fourier transform infrared spectrum of the silica aerogel, the absolute value of the difference in absorbance of a first characteristic peak and a second characteristic peak is 0.02 or more, preferably 0.021-0.039, the first characteristic peak is located at a wave number of 861-865cm -1 , and the second characteristic peak is located at a wave number of 910-920cm -1 ; the decay rate of the absorbance in the Fourier transform infrared spectrum of the silica aerogel before and after being placed in an environment of 180℃ for 4 hours is ≤3%, preferably 0.5%-3% at a wave number of 1082cm -1 . By controlling the absolute value of the difference in absorbance of the first characteristic peak at a wave number of 861-865cm -1 and the second characteristic peak at a wave number of 910-920cm -1 in the infrared spectrum of the silica aerogel to be within the above range, and the infrared spectrum of the silica aerogel after environmental treatment, the decay rate of the absorbance at a wave number of 1082cm -1The absorbance of the wave number is in the above range compared to the decay rate before the environmental treatment, so that the silica gel foam of the present application has better low resilience loss and low outgassing, thereby having better buffering, waterproofing, sealing and other effects.

[0035] Specifically, by controlling the absolute value of the difference between the absorbance of the first characteristic peak at a wave number of 861-865 cm -1 and the absorbance of the second characteristic peak at a wave number of 910-920 cm -1 in the infrared spectrum of the silica gel foam before the environmental treatment to be in the above range, and controlling the infrared spectrum of the silica gel foam after the environmental treatment to be at 1082 cm -1 , the silica gel foam of the present application has better low resilience loss and low outgassing, thereby having better buffering, waterproofing, sealing and other effects.

[0036] In some embodiments, the absorbance of the first characteristic peak in the Fourier transform infrared spectrum of the silica gel foam is 0.033-0.040.

[0037] In some embodiments, the absorbance of the second characteristic peak in the Fourier transform infrared spectrum of the silica gel foam is 0.001-0.014.

[0038] In some embodiments, the silica gel foam is placed in a 100℃ environment for 24 hours in a compressed state at a compression rate of 25%, then the compression is removed, and then placed in a room temperature environment (23±2℃) for 0.5 hours, and the 25% relative compression permanent set rate is 3% or less. The 25% relative compression permanent set rate is calculated by the following formula:

[0039] P = T2 ÷ T1 × 100%,

[0040] wherein P is the 25% relative compression permanent set rate, %;

[0041] T2 is the difference between the thickness of the silica gel foam before compression and the thickness of the silica gel foam after the compression is removed and placed in a room temperature environment for 0.5 hours, in mm;

[0042] T1 is the thickness of the silica gel foam before compression, in mm.

[0043] In some embodiments, the silica gel foam has a 70% relative compression permanent deformation rate of less than or equal to 5% after being compressed at a compression rate of 70%, being placed in an environment of 100℃ for 24 hours, being decompressed, and then being placed in an environment of room temperature (23±2℃) for 0.5 hours, wherein the 70% relative compression permanent deformation rate is calculated according to the following formula:

[0044] Q = R2 ÷ R1 x 100%,

[0045] Q is the 70% relative compression permanent deformation rate, %;

[0046] R2 is the difference between the thickness of the silica gel foam before compression and the thickness of the silica gel foam after being decompressed and placed in an environment of room temperature for 0.5 hours, in mm;

[0047] R1 is the thickness of the silica gel foam before compression, in mm.

[0048] By controlling the 25% relative compression permanent deformation rate and the 70% relative compression permanent deformation rate of the silica gel foam within the above ranges, the silica gel foam has low resilience loss.

[0049] In some embodiments, the silica gel foam has a million times compression thickness decay rate of less than or equal to 1.5%, wherein the million times compression thickness decay rate of the silica gel foam is tested by the following method: the silica gel foam is compressed from a compression rate of 0 to a compression rate of 50% and then decompressed, which is recorded as 1 compression, the compression frequency is 2.5 Hz, and after 1 million times of the compression, the million times compression thickness decay rate is tested.

[0050] By controlling the thickness decay rate of the silica gel foam to be less than or equal to 1.5% after 1 million times of compression, the content of unreacted substances and active groups in the silica gel foam is further controlled to be low, which not only further ensures that the silica gel foam has excellent resilience and thus has better low resilience loss, but also further ensures that the silica gel foam has low outgassing. If the thickness decay rate of the silica gel foam after 1 million times of compression is greater than 1.5%, the content of unreacted substances and active groups in the silica gel foam is high, which causes the adhesion and secondary reaction of these substances during repeated compression, resulting in the shrinkage and adhesion of the internal structure of the foam, affecting the resilience of the silica gel foam, causing high resilience loss, and causing the silica gel foam to release small molecule substances. The active groups refer to groups that can participate in polymerization but actually do not participate in polymerization, which can be groups from raw materials or impurities mixed in the preparation process.

[0051] In some embodiments, the silica gel foam is placed in a vacuum environment at 150℃ and a vacuum degree of 7x10 -3the mass loss rate (ML) of the silica gel foam after being placed in the environment Pa for 24 hours is ≤1%, and the mass of the collectable condensate (CV) generated accounts for ≤0.5% of the mass of the silica gel foam. Preferably, the silica gel foam is placed in an environment with a temperature of 150°C and a vacuum degree of 7x10 -3 the mass loss rate of the silica gel foam after being placed in the environment Pa for 24 hours is 0.3%-0.9%, and the mass of the collectable condensate generated accounts for 0.1%-0.45% of the mass of the silica gel foam. The collectable condensate mainly includes incompletely reacted small-molecule silicone oil and impurity mixed ring D3-D10.

[0052] The present application controls the mass loss rate and the mass proportion of the collectable condensate to be within the above ranges, so that the silica gel foam has a low environmental mass loss rate and further has a low outgassing property.

[0053] The mass loss rate and the mass proportion of the collectable condensate to the mass of the silica gel foam are tested by the following method:

[0054] The silica gel foam (with a planar size of 20cmx20cm and a thickness of the foam prepared in the following examples) is preprocessed by being placed in an environment with a temperature of 23°C and a relative humidity (RH) of 50% for 24 hours, to obtain preprocessed silica gel foam; then the preprocessed silica gel foam is placed in an environment with a temperature of 150°C and a vacuum degree of 7x10 -3 The silica gel foam is cooled to room temperature (23±2°C) after being placed in the environment Pa for 24 hours; then the silica gel foam is pressurized to normal pressure (i.e. 101.325kPa) by using dry protective gas, and the gas generated by the silica gel foam is condensed and collected on a pre-weighed collection plate at a constant temperature of 25°C, to obtain collectable condensate; the mass loss rate of the silica gel foam and the mass proportion of the collectable condensate to the mass of the silica gel foam are tested.

[0055] In some specific embodiments, the compressive stress retention rate of the silica gel foam after being compressed for 1min and 30min at a compression rate of 30%-80% and at room temperature (23±2°C) is ≥80%. Preferably, the compressive stress retention rate of the silica gel foam after being compressed for 1min at a compression rate of 30%-80% and at room temperature is 90%-97%, and the compressive stress retention rate after being compressed for 30min is 80%-90%.

[0056] The present application controls the compression resilience stress retention rate of the silica gel foam under certain conditions in the above range, and further controls the addition amount of the inorganic filler and the like powder and the addition amount of the silicone oil in the raw material of the silica gel foam in a suitable range, thereby avoiding the loss of elasticity of the foam due to the excessive addition amount of the inorganic filler and the like powder, the permanent damage of the foam after compression, the phenomenon of the polarity adhesion of the foam caused by the excessive addition amount of the silicone oil, and further improving the low resilience loss of the foam.

[0057] In some embodiments, the silica gel foam is placed in an environment of 85℃ and 85% relative humidity (RH) at a compression rate of 50% for 1000 hours, and then the compression is removed, and then the thickness change rate of the silica gel foam is ≤3% after being placed in a room temperature environment (23±2℃) for 0.5 hours, preferably 0.2%-3%.

[0058] The present application controls the thickness change rate of the silica gel foam after environmental compression in the above range, which is beneficial to reduce the content of free Si-OH in the foam, avoids the problem of polarity adhesion of the foam and the inability to quickly rebound during environmental compression, and further ensures the low resilience loss of the foam.

[0059] In some embodiments, the 25% compression stress of the silica gel foam is 50-200kPa.

[0060] In some embodiments, the density of the silica gel foam is 300-550kg / m 3 , preferably 300-500kg / m 3 .

[0061] In some embodiments, the thickness of the silica gel foam is 0.5-16mm, preferably 2-8mm.

[0062] The present application controls the 25% compression stress, density and thickness of the silica gel foam in the above range, so that the silica gel foam has suitable compression strength and other mechanical properties, thereby having a better buffering effect when used in the battery box.

[0063] <Raw material of the silica gel foam>

[0064] In some embodiments, the raw material of the silica gel foam of the present application comprises component A and component B;

[0065] The component A at least comprises: high-viscosity vinyl silicone oil, low-viscosity vinyl silicone oil, structure aid, and a mixture of base silicone resin and the like;

[0066] The component B at least includes: high viscosity vinyl silicone oil, low viscosity vinyl silicone oil, chain extender, and matrix silicone resin mixture, etc.

[0067] In some embodiments, the weight ratio of the component A to the component B is (0.8-1): 1.

[0068] In some embodiments, the content of the high viscosity vinyl silicone oil in the component A can be 2%-13% based on 100% of the total weight of the component A.

[0069] In some embodiments, the content of the low viscosity vinyl silicone oil in the component A can be 24%-35% based on 100% of the total weight of the component A.

[0070] In some embodiments, the content of the structural aid can be 0.4%-1.5% based on 100% of the total weight of the component A. Preferably, the structural aid includes one or a combination of several of glycerol, water, ethanol, and isopropyl alcohol, etc.

[0071] In some embodiments, the matrix silicone resin mixture in the component A can include a first matrix silicone resin mixture and a second matrix silicone resin mixture, the content of the first matrix silicone resin mixture being 3%-15% and the content of the second matrix silicone resin mixture being 35%-50% based on 100% of the total weight of the component A.

[0072] In some embodiments, the component A can further include hydroxyl silicone oil. The content of the hydroxyl silicone oil can be 4%-12% based on 100% of the total weight of the component A. Preferably, the mass content of the hydroxyl group in the hydroxyl silicone oil is ≥8%.

[0073] In some embodiments, the component A can further include catalyst. The content of the catalyst can be 1%-3% based on 100% of the total weight of the component A. The catalyst is for example but not limited to platinum gold catalyst. Preferably, the effective platinum content in the platinum gold catalyst is 4000-5000 ppm.

[0074] In some embodiments, the component A can further include or not include color paste. The content of the color paste can be 0%-0.6% based on 100% of the total weight of the component A, and can be 0.2%-0.6% if the color paste is included. The color paste can adopt silica gel color paste which is conventional in the art.

[0075] In some embodiments, the content of the high viscosity vinyl silicone oil in the component B can be 6%-20% based on 100% of the total weight of the component B.

[0076] In some embodiments, the low viscosity vinyl silicone oil in the component B can be present in an amount of 25-40% based on 100% of the total weight of the component B.

[0077] In some embodiments, the chain extender can be present in an amount of 1-5% based on 100% of the total weight of the component B. Preferably, the chain extender comprises a low hydrogen-containing silicone oil. More preferably, the low hydrogen-containing silicone oil has a hydrogen mass content of 0.03-0.5% and a viscosity of 10-1000 mpa·s.

[0078] In some embodiments, the base silicone resin mixture in the component B can comprise a first base silicone resin mixture and a second base silicone resin mixture, the first base silicone resin mixture being present in an amount of 6-18% and the second base silicone resin mixture being present in an amount of 30-45% based on 100% of the total weight of the component B.

[0079] In some embodiments, the component B can further comprise a high hydrogen-containing silicone oil. The high hydrogen-containing silicone oil can be present in an amount of 3-10% based on 100% of the total weight of the component B. Preferably, the high hydrogen-containing silicone oil has a hydrogen mass content of 1.2-1.7% and a viscosity of 20-100 mpa·s.

[0080] In some embodiments, the component B can further comprise a hydrosilylation inhibitor. The hydrosilylation inhibitor can be present in an amount of 0.05-0.3% based on 100% of the total weight of the component B. Preferably, the hydrosilylation inhibitor comprises one or a combination of ethynylcyclohexanol, 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, t-butylcyclohexanol, and phenylbutynol.

[0081] In some embodiments, the high viscosity vinyl silicone oil has a viscosity of 100000-200000 mpa·s and a mass content of vinyl of 0.03-0.07%. Preferably, the high viscosity vinyl silicone oil is a terminal vinyl silicone oil. For example, a mono-terminal vinyl silicone oil and / or a di-terminal vinyl silicone oil.

[0082] In some embodiments, the low viscosity vinyl silicone oil has a viscosity of 1000-20000 mpa·s and a mass content of vinyl of 0.07-0.9%. Preferably, the low viscosity vinyl silicone oil is a terminal vinyl silicone oil. For example, a mono-terminal vinyl silicone oil and / or a di-terminal vinyl silicone oil.

[0083] In some embodiments, the first base silicone resin mixture includes the following components in parts by weight: 20-50 parts (preferably 30-40 parts) of a vinyl silicone oil having a viscosity of 500-2000 mpa-s (preferably 1000 mpa-s), 40-70 parts (preferably 55-65 parts) of a vinyl silicone oil having a viscosity of 4000-20000 mpa-s (preferably 4000-10000 mpa-s), 5-10 parts of a reinforcing agent, and 1-3 parts of a silazane.

[0084] In some embodiments, the second base silicone resin mixture includes the following components in parts by weight: 10-30 parts (preferably 15-25 parts) of a vinyl silicone oil having a viscosity of 10000-60000 mpa-s (preferably 10000-20000 mpa-s), 15-35 parts (preferably 20-30 parts) of a vinyl silicone oil having a viscosity of 60000-200000 mpa-s (preferably 100000 mpa-s), 20-60 parts (preferably 35-45 parts) of an inorganic flame retardant, 5-20 parts of a filler, and 1-4 parts of a silane coupling agent.

[0085] In some embodiments, the first base silicone resin mixture has a viscosity of 80-120 million mpa-s.

[0086] In some embodiments, the second base silicone resin mixture has a viscosity of 30-60 million mpa-s.

[0087] In some embodiments, among the components of the first base silicone resin mixture, the vinyl silicone oil having a viscosity of 500-2000 mpa-s and the vinyl silicone oil having a viscosity of 4000-20000 mpa-s can each be a terminal vinyl silicone oil. For example, a mono-terminal vinyl silicone oil and / or a di-terminal vinyl silicone oil.

[0088] In some embodiments, among the components of the first base silicone resin mixture, the reinforcing agent can include white carbon, etc. For example, a precipitated white carbon and / or a fumed white carbon, etc. Preferably, the white carbon has a specific surface area of 200-400 m 2 / g.

[0089] In some embodiments, among the components of the first base silicone resin mixture, the silazane can include one or a combination of several of hexamethyldisilazane, heptamethyldisilazane, and tetramethyldisilazane, etc., preferably hexamethyldisilazane.

[0090] In some embodiments, in the components of the second base silicone resin mixture, the vinyl silicone oil with a viscosity of 10,000-60,000 mpa·s and the vinyl silicone oil with a viscosity of 60,000-200,000 mpa·s can each be a terminal vinyl silicone oil. For example, a mono-terminal vinyl silicone oil and / or a di-terminal vinyl silicone oil.

[0091] In some embodiments, in the components of the second base silicone resin mixture, the inorganic flame retardant can employ an inorganic flame-retardant powder that is conventional in the art, such as one or a combination of several of aluminum hydroxide, magnesium hydroxide, and zinc oxide, etc. Preferably, the particle size D50 of the inorganic flame-retardant powder is 1-10 μm. More preferably, the particle size D50 of the inorganic flame-retardant powder is 3-6 μm.

[0092] In some embodiments, in the components of the second base silicone resin mixture, the filler can employ a filler powder that is conventional in the art, such as one or a combination of several of calcium carbonate, magnesium carbonate, and silicon micro powder, etc. Preferably, the particle size D50 of the filler powder is 3-10 μm.

[0093] In some embodiments, in the components of the second base silicone resin mixture, the silane coupling agent includes a long-chain silane coupling agent. Specifically, it can include one or a combination of several of n-octyl trialkoxysilane, dodecyl trialkoxysilane, hexadecyl trialkoxysilane, and octadecyl trialkoxysilane, etc.; more specifically, it can include one or a combination of several of n-octyl trimethoxysilane, n-octyl triethoxysilane, dodecyl trimethoxysilane, dodecyl triethoxysilane, hexadecyl trimethoxysilane, hexadecyl triethoxysilane, octadecyl trimethoxysilane, and octadecyl triethoxysilane, etc.

[0094] <Method for preparing silicone gel foam>

[0095] In some embodiments, the method for preparing the silicone gel foam of the present application can include the following steps:

[0096] (1) Raw material pretreatment:

[0097] The high-viscosity vinyl silicone oil, the low-viscosity vinyl silicone oil, the vinyl silicone oil with a viscosity of 500-2000 mpa·s, the vinyl silicone oil with a viscosity of 4000-20000 mpa·s, the vinyl silicone oil with a viscosity of 10000-60000 mpa·s, and the vinyl silicone oil with a viscosity of 60000-200000 mpa·s are heated to a first temperature under normal pressure, then are treated at the first temperature under vacuum for a first time, and then are cooled to room temperature (generally 23±2℃) and kept for a second time, to obtain the pretreated vinyl silicone oils, respectively;

[0098] (2) Preparation of a first base silicone resin mixture:

[0099] The components of the first base silicone resin mixture (using the pretreated vinyl silicone oils described above) are mixed, heated to a second temperature, and stirred for a third time, and then treated at the second temperature under vacuum for a fourth time, to obtain the first base silicone resin mixture;

[0100] (3) Preparation of a second base silicone resin mixture:

[0101] The components of the second base silicone resin mixture (using the pretreated vinyl silicone oils described above) are mixed, heated to a third temperature, and stirred for a fifth time, and then treated at the third temperature under vacuum for a sixth time, to obtain the second base silicone resin mixture;

[0102] (4) Preparation of a silicone foam:

[0103] The components of the component A and the component B (using the pretreated vinyl silicone oils described above and the first base silicone resin mixture and the second base silicone resin mixture prepared above) are mixed respectively to obtain the component A and the component B, respectively; the component A and the component B are mixed, and then molded and vulcanized to obtain the silicone foam.

[0104] In some embodiments, in step (1), the first temperature can be 160-170℃.

[0105] In some embodiments, in step (1), the first time and the second time can be 30-60 min, respectively.

[0106] In some embodiments, in step (2), the second temperature can be 120-130℃.

[0107] In some embodiments, in step (2), the third time can be 1-1.5 h.

[0108] In some embodiments, in step (2), the fourth time can be 2-2.5 h.

[0109] In some embodiments, in step (3), the third temperature can be 130-140℃.

[0110] In some embodiments, in step (3), the fifth time can be 2-2.5 h.

[0111] In some embodiments, in step (3), the sixth time can be 1-1.5 h.

[0112] In some embodiments, in steps (1), (2) and (3), the vacuum degree of the vacuum condition can be, for example but not limited to, -80 kpa.

[0113] In some embodiments, in step (4), the forming can be performed in a calender, for example.

[0114] In some embodiments, in step (4), the vulcanization can include primary vulcanization and secondary vulcanization, the temperature of the primary vulcanization can be 50-80℃, the time can be 3-10 min, the temperature of the secondary vulcanization can be 150-180℃, and the time can be 20-30 min.

[0115] It should be noted that, in the preparation process of the silica gel foam of the present application, Si-OH and Si-H in the reaction raw materials produce hydrogen gas and then foam (a foaming agent can not be added separately) to form a cross-linked foamed body, and then the silica gel foam of the present application is obtained.

[0116] <Applications>

[0117] The silica gel foam provided by the present application is suitable for application in a battery box, which can include a lower box body and an upper box body connected with the lower box body; the lower box body includes a frame, a liquid cooling plate arranged at the bottom of the frame, and a bottom guard plate arranged at the lower part of the liquid cooling plate, and the frame includes a frame and a plurality of beam bodies connected with the frame; the upper box body includes a top plate and a side plate; the silica gel foam is arranged between the lower box body and the upper box body, and / or the silica gel foam is arranged between the liquid cooling plate and the bottom guard plate.

[0118] It should be noted that, in general, a battery module can be arranged in the frame of the lower box body, and then a battery pack is composed of the battery module and the battery box.

[0119] The silica gel foam in the prior art still has the following problems, which makes them unsuitable for application in battery packs: (1) If the silica gel foam is expected to have high and fast resilience, it is usually necessary to add more low molecular silicone oil to participate in the reaction in the process of preparing the silica gel foam, and part of the auxiliary needs to be introduced into the raw material system with low molecular substances as the carrier. The silica gel foam prepared from these raw materials will slowly release the gas that does not fully participate in the reaction under special temperature and pressure conditions, thereby causing pollution to the battery pack and reducing the vacuum degree of the sealed space of the battery pack. (2) If the silica gel foam is expected to have low outgassing, it is usually necessary to reduce the addition of silicone oil, especially the addition of low molecular silicone oil, so that the content of inorganic powder in the raw material system is increased, which increases the interstitial of the silica gel foam and seriously damages the resilience performance. At the same time, the addition of more inorganic powder can easily cause the toughness of the silica gel foam to deteriorate sharply, and the product is brittle, which cannot meet the long-term use requirement. (3) With the increase of use time, small molecular substances in the silica gel foam can migrate, and at the same time, with the aging of the silica gel foam itself, these small molecular substances will be released, which will form a separation layer in the battery box of the battery pack, which will cause corrosion and pollution to the silica gel foam itself, and also cause the insulation performance of the battery box to decrease, which has certain safety hidden danger.

[0120] Compared with the silica gel foam in the prior art, the silica gel foam of the present application has low outgassing and low resilience loss, and is suitable for application in new energy battery packs (usually arranged in the battery box), which can be used as a sealing ring and / or a buffer pad, etc., and has better buffering, waterproofing, sealing, etc.

[0121] <TEST METHODS>

[0122] 1. Fourier transform infrared spectroscopy

[0123] Equipment: Fourier transform infrared spectrometer (FTIR, Thermo Scientific, model: Nicolet iS20, ATR accessory: GE).

[0124] Scan range: 2000-4000 cm -1 ; Mode: absorbance; scan times: 32 times.

[0125] The test steps include scanning background, sampling, scanning sample, and observing spectrum, etc. Specifically, it can include: (1) turning on the Fourier transform infrared spectrometer and stabilizing for 0.5 hours; (2) turning on the computer and opening the OMNIC software, running the menu, checking the stability of the infrared spectrometer, and selecting the ATR accessory; (3) taking a circular piece-shaped silica gel foam sample with a diameter of more than 3 mm and a thickness of 1 mm, placing the sample under the probe of the Fourier transform infrared spectrometer, and fixing the sample; (4) scanning the empty light path background signal first, then scanning the sample infrared signal, and obtaining the infrared data of the sample by Fourier transform; (5) clicking the menu bar "Data Processing - Automatic Baseline Correction" of the OMNIC software to perform baseline correction, and obtaining the infrared spectrum of the sample. The circular piece-shaped silica gel foam sample with a thickness of 1 mm can be prepared by slicing the foam.

[0126] The absorbance (arbitrary unit, a.u.) of the first characteristic peak at a wave number of 861-865 cm -1 and the second characteristic peak at a wave number of 910-920 cm -1 in the Fourier transform infrared spectrum of the silica gel foam sample is directly obtained by observing the spectrum. Based on the absorbance of the first characteristic peak and the second characteristic peak directly obtained by observing the spectrum, the absolute value of the difference between the two is calculated. Before and after the silica gel foam sample is placed in an environment at 180℃ for 4 hours, the decay rate of the absorbance at a wave number of 1082 cm -1 in the Fourier transform infrared spectrum of the silica gel foam sample is calculated by the following method: the absorbance at a wave number of 1082 cm -1 in the Fourier transform infrared spectrum of the silica gel foam sample is set as A1, and the absorbance at a wave number of 1082 cm -1 in the Fourier transform infrared spectrum of the silica gel foam sample after being placed in an environment at 180℃ for 4 hours is set as A2, and the decay rate of the absorbance is calculated by (A1-A2) ÷ A1 × 100%.

[0127] 2.25% relative compression permanent set and 70% relative compression permanent set

[0128] After the silica gel foam sample is placed in a compressed state at a compression rate of 25% in an environment at 100℃ (relative humidity (RH) is 45%-55%) for 24 hours, the compression is removed, and then it is placed in a room temperature environment (23±2℃, relative humidity (RH) is 45%-55%) for 0.5 hours, the 25% relative compression permanent set is calculated by the following formula:

[0129] P = T2 ÷ T1 × 100%,

[0130] wherein P is the 25% relative compression permanent set, %.

[0131] T2 is the difference between the thickness of the silica gel foam sample before compression and the thickness of the silica gel foam sample after the compression is removed and it is placed in a room temperature environment for 0.5 hours, mm;

[0132] T1 is the thickness of the silica gel foam sample before compression, mm.

[0133] The 70% relative compression permanent set rate of the silica gel foam sample is calculated by the following formula after the sample is placed in a 100℃ environment (relative humidity (RH) is 45%-55%) for 24 hours in a compressed state with a compression rate of 70%, the compression is removed, and then it is placed in a room temperature environment (23±2℃, relative humidity (RH) is 45%-55%) for 0.5 hours:

[0134] Q = R2 ÷ R1 × 100%,

[0135] Wherein, Q is the 70% relative compression permanent set rate, %;

[0136] R2 is the difference between the thickness of the silica gel foam sample before compression and the thickness of the silica gel foam sample after the compression is removed and it is placed in a room temperature environment for 0.5 hours, mm;

[0137] R1 is the thickness of the silica gel foam sample before compression, mm.

[0138] Wherein, the sample used in the test can be a cylindrical sample with a diameter of 29 mm, and the initial thickness of the sample can be 12.5 mm or more. If the thickness of the silica gel foam is less than 12.5 mm, the thickness of the test sample is made to be more than 12.5 mm by stacking multiple pieces of foam.

[0139] 3. Million times compression thickness decay rate

[0140] The test is carried out according to the method recorded in GB / T 18941-2003.

[0141] The specific method includes:

[0142] The test environment is: temperature is 23±2℃, relative humidity (RH) is 45%-55%; in the test environment, using a repeated compression tester (for example, LT-JJ36-B repeated compression tester), the silica gel foam sample is compressed from a compression rate of 0 to a compression rate of 50%, and then the compression is removed, which is recorded as 1 compression, the compression frequency is 2.5 Hz, and the compression is performed for 1 million times. The thickness of the silica gel foam sample before and after compression is tested using a thickness gauge. The calculation of the thickness attenuation rate per million times of compression is as follows: during the first 100,000 times of compression, the thickness attenuation rate of the sample is calculated after every 10,000 times of compression; during the 100,000th to 1,000,000th compression, the thickness attenuation rate of the sample is calculated after every 100,000 times of compression; the average of all the calculated thickness attenuation rates is taken to obtain the thickness attenuation rate per million times of compression. Wherein, the initial thickness of the sample before compression is set as Z1, and the thickness of the sample after compression is set as Z2, and the thickness attenuation rate is calculated by (Z1-Z2)÷Z1×100%. Wherein, the sample used in this test can be a cylindrical sample with a diameter of 29 mm, and the initial thickness of the sample is the thickness of the foam prepared in the following examples.

[0143] 4. Environmental quality loss rate and proportion of collectable condensate to the mass of silica gel foam

[0144] The test is performed according to the method described in ASTM E595-15 (2021).

[0145] The specific method includes:

[0146] The silica gel foam sample is weighed to obtain the mass of the silica gel foam sample, which is recorded as m1; then the silica gel foam sample is placed in a container at 23℃ and 50% relative humidity (RH) for 24 hours for pretreatment to obtain a pretreated silica gel foam sample; then the container containing the pretreated silica gel foam sample is placed in the sample chamber of a test device (for example, AST-OTS TM -E595 vacuum outgassing test mass loss apparatus), and the test device is sealed; the environment in the sample chamber of the test device is brought to a vacuum degree of 7×10 -3 Pa and a temperature of 150℃, and after maintaining for 24 hours, the test device is cooled to room temperature (generally 23±2℃); then the sample chamber of the test device is pressurized to normal pressure (i.e. 101.325 kPa) with dry protective gas (for example, nitrogen), the gas flowing out of the sample chamber is condensed and collected on a pre-weighed collection plate at a constant temperature of 25℃ to obtain collectable condensate; the silica gel foam sample and the collection plate are taken out and weighed respectively to obtain the mass of the silica gel foam sample at 150℃ and a vacuum degree of 7×10 -3The mass of the silica gel foam sample after the environment is placed for 24 hours is recorded as m2, and the mass of the collectable condensate is recorded as m3; the mass loss rate is calculated by (m1-m2) ÷ m1 x 100%, and the proportion of the mass of the collectable condensate to the mass of the silica gel foam is calculated by m3 ÷ m1 x 100%. In this test, the planar size of the sample is 20 cm x 20 cm, and the thickness of the sample is the thickness of the foam prepared in the following examples.

[0147] 5. Compression resilience stress retention rate

[0148] The test is performed according to the method described in ASTM D1056-2014.

[0149] The specific method includes:

[0150] At room temperature (generally 23±2℃), the silica gel foam sample is compressed using a repeated compression testing machine (for example, an LT-JJ36-B repeated compression testing machine). The instantaneous compression stress F1 (i.e., the initial stress value when the compression rate reaches the above-mentioned compression rate), the compression stress F2 after 1 min of compression, and the compression stress F3 after 30 min of compression are recorded at compression rates of 30%, 40%, 50%, 60%, 70%, and 80%, respectively. The compression resilience stress retention rate after 1 min of compression at the above-mentioned different compression rates is calculated by F2 ÷ F1 x 100%, and the compression resilience stress retention rate after 30 min of compression at the above-mentioned different compression rates is calculated by F3 ÷ F1 x 100%. Then, the compression resilience stress retention rates after 1 min of compression at different compression rates are averaged to obtain the compression resilience stress retention rate after 1 min of compression at a compression rate of 30%-80%. The compression resilience stress retention rates after 30 min of compression at different compression rates are averaged to obtain the compression resilience stress retention rate after 30 min of compression at a compression rate of 30%-80%. In this test, the sample can be a cylindrical sample with a diameter of 29 mm, and the initial thickness of the sample can be more than 4 mm. If the thickness of the silica gel foam is less than 4 mm, the thickness of the test sample is increased to more than 4 mm by stacking multiple pieces of foam.

[0151] 6. Double 85 environmental compression thickness change rate

[0152] The test is performed according to the method described in ASTM D1056-2014.

[0153] The specific method includes:

[0154] The silica gel foam sample is placed in an environment of 85℃ and 85% relative humidity (RH) for 1000 hours in a compressed state at a compression rate of 50%, then decompressed, and then placed in an environment of room temperature (23±2℃) for 0.5 hours (ambient humidity is not specially required, for example, relative humidity (RH) is 45%-55%). The thickness of the silica gel foam sample before and after the test is tested using a thickness gauge. The initial thickness of the sample before the test is set as H1, and the thickness of the sample after the test is set as H2, and the thickness change rate is calculated by (H1-H2)÷H1×100%. The sample used in the test can be a cylindrical sample with a diameter of 29 mm, and the initial thickness of the sample can be more than 4 mm. If the thickness of the silica gel foam is less than 4 mm, the thickness of the test sample is made to be more than 4 mm by stacking multiple pieces of foam.

[0155] 7. 25% compression stress

[0156] The test is performed according to the method described in ASTM D1056-2014. The sample used in the test can be a cylindrical sample with a diameter of 29 mm, and the initial thickness of the sample can be more than 4 mm. If the thickness of the silica gel foam is less than 4 mm, the thickness of the test sample is made to be more than 4 mm by stacking multiple pieces of foam.

[0157] 8. Density

[0158] The test is performed according to the method described in ASTM D1056-2014.

[0159] 9. Thickness

[0160] The thickness of the silica gel foam is tested using a thickness gauge.

[0161] 10. Low outgassing evaluation

[0162] If the test results of the mass loss rate and the proportion of collectable condensate are within the scope of the present application, the low outgassing evaluation result is OK, and if one or more of the above test results are not within the scope of the present application, the low outgassing evaluation result is NG.

[0163] 11. Low resilience loss evaluation

[0164] If the test results of the 25% relative compression permanent set, the 70% relative compression permanent set, the million times compression thickness decay rate, the compression resilience stress retention rate after 1 min of compression, the compression resilience stress retention rate after 30 min of compression, and the double 85 environment compression thickness change rate are within the scope of the present application, the low resilience loss evaluation result is OK, and if one or more of the above test results are not within the scope of the present application, the low resilience loss evaluation result is NG.

[0165] <EMBODIMENT>

[0166] The technical solutions of the present application are specifically illustrated below by examples, but the present application is not limited to these examples, and various modifications can of course be made within the scope of the gist of the present application to implement the present application.

[0167] The raw materials used in the examples and comparative examples are as follows:

[0168] The high-viscosity vinyl silicone oil is a terminal vinyl silicone oil with a vinyl mass content of 0.06% and a viscosity of 100,000 mpa.s: HV-100,000; or a terminal vinyl silicone oil with a vinyl mass content of 0.04% and a viscosity of 165,000 mpa.s: HV-165,000;

[0169] The low-viscosity vinyl silicone oil is a terminal vinyl silicone oil with a vinyl mass content of 0.3% and a viscosity of 1,000 mpa.s: HV-1,000; or a terminal vinyl silicone oil with a vinyl mass content of 0.2% and a viscosity of 2,000 mpa.s: HV-2,000;

[0170] The structure aid is glycerol, industrial grade; or isopropanol, industrial grade;

[0171] The hydroxyl silicone oil has a hydroxyl mass content of 8.5%: 207V-10 hydroxyl silicone oil;

[0172] The platinum gold catalyst has an effective platinum content of 5,000 ppm: PT-5,000 platinum gold catalyst;

[0173] The color paste is a blue-gray color paste;

[0174] The chain extender is a low-hydrogen silicone oil with a hydrogen mass content of 0.05% and a viscosity of 30-50 mpa.s: DY-H201 low-hydrogen silicone oil; or a low-hydrogen silicone oil with a hydrogen mass content of 0.2% and a viscosity of 30-50 mpa.s: DY-H204 low-hydrogen silicone oil;

[0175] The high-hydrogen silicone oil has a hydrogen mass content of 1.6% and a viscosity of 30-80 mpa.s: DY-H202 high-hydrogen silicone oil;

[0176] The hydrosilylation inhibitor is ethynylcyclohexanol;

[0177] The terminal vinyl silicone oil has a viscosity of 1,000 mpa.s: HV-1,000;

[0178] The terminal vinyl silicone oil has a viscosity of 10,000 mpa.s: HV-10,000;

[0179] The reinforcing agent is a fumed silica with a specific surface area of 200 m 2 / g; or a precipitated silica with a specific surface area of 300 m 2 / g;

[0180] The silazane is hexamethyldisilazane;

[0181] The end-vinyl silicone oil with a viscosity of 20,000 mPa·s is HV-20,000;

[0182] The end-vinyl silicone oil with a viscosity of 100,000 mPa·s is HV-100,000;

[0183] The inorganic flame retardant is a mixture of aluminum hydroxide powder, magnesium hydroxide powder and zinc oxide powder with a D50 particle size of 3-6 μm, and the mass ratio of the aluminum hydroxide powder, the magnesium hydroxide powder and the zinc oxide powder is 2:1:1;

[0184] The filler is silicon powder with a D50 particle size of 3-10 μm, or calcium carbonate with a D50 particle size of 6-10 μm;

[0185] The silane coupling agent is hexadecyltrimethoxysilane.

[0186] Example 1

[0187] The present example provides a silica gel foam, which is prepared from components A and B with a weight ratio of 1:1;

[0188] The component A is composed of the following raw materials, with the total weight of the component A being 100%: high-viscosity vinyl silicone oil 4.84%, low-viscosity vinyl silicone oil 31.43%, structural aid 0.97%, first base silicone resin mixture 7.25%, second base silicone resin mixture 45.94%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%; wherein the high-viscosity vinyl silicone oil is HV-100,000, the low-viscosity vinyl silicone oil is HV-2000, and the structural aid is glycerol;

[0189] The component B is composed of the following raw materials, with the total weight of the component B being 100%: high-viscosity vinyl silicone oil 12.43%, low-viscosity vinyl silicone oil 31.50%, chain extender 2.07%, first base silicone resin mixture 12.43%, second base silicone resin mixture 35.23%, high-hydrogen silicone oil 6.22%, and silicon-hydrogen addition inhibitor 0.12%; wherein the high-viscosity vinyl silicone oil is HV-100,000, the low-viscosity vinyl silicone oil is HV-2000, and the chain extender is DY-H201 low-hydrogen silicone oil;

[0190] The first base silicone resin mixture includes the following components in parts by weight: end-vinyl silicone oil with a viscosity of 1,000 mPa·s 34 parts, end-vinyl silicone oil with a viscosity of 10,000 mPa·s 60 parts, reinforcing agent 5 parts, and silazane 1 part;

[0191] The second base silicone resin mixture comprises the following components by weight parts: end-vinyl silicone oil with viscosity of 20,000 mpa·s 20 parts, end-vinyl silicone oil with viscosity of 100,000 mpa·s 24 parts, inorganic flame retardant 40 parts, filler 15 parts, and silane coupling agent 1 part;

[0192] wherein the reinforcing agent is fumed silica with specific surface area of 200 m 2 / g; and the filler is silicon powder.

[0193] The viscosity of the first base silicone resin mixture is 90-100 million mpa·s. The viscosity of the second base silicone resin mixture is 30-40 million mpa·s.

[0194] The preparation method of the silica gel foam comprises the following steps:

[0195] (1) Pretreatment of raw materials:

[0196] The high-viscosity vinyl silicone oil, low-viscosity vinyl silicone oil, end-vinyl silicone oil with viscosity of 1,000 mpa·s, end-vinyl silicone oil with viscosity of 10,000 mpa·s, end-vinyl silicone oil with viscosity of 20,000 mpa·s, and end-vinyl silicone oil with viscosity of 100,000 mpa·s are heated to 170℃ under normal pressure conditions, then pressure-keeping treatment is carried out under vacuum degree of -80 kpa for 30 min, and then cooled to room temperature and kept for 30 min, to obtain each vinyl silicone oil after pretreatment, respectively;

[0197] (2) Preparation of the first base silicone resin mixture:

[0198] After mixing the components of the first base silicone resin mixture (using the above-mentioned vinyl silicone oil after pretreatment), heating to 120℃ and stirring for 1 h, then pressure-keeping treatment is carried out under vacuum degree of -80 kpa for 2 h, to obtain the first base silicone resin mixture;

[0199] (3) Preparation of the second base silicone resin mixture:

[0200] After mixing the components of the second base silicone resin mixture (using the above-mentioned vinyl silicone oil after pretreatment), heating to 130℃ and stirring for 2 h, then pressure-keeping treatment is carried out under vacuum degree of -80 kpa for 1 h, to obtain the second base silicone resin mixture;

[0201] (4) Preparation of the silica gel foam:

[0202] After mixing the components of component A and component B (the above-mentioned pre-processed vinyl silicone oil and the above-mentioned first base silicone resin mixture and second base silicone resin mixture) respectively, component A and component B are obtained; component A and component B are mixed in a weight ratio of 0.857:1; then the obtained mixture is poured into a calendering machine for calendering molding; then the obtained molding is subjected to primary vulcanization at a temperature of 80°C for 5 min; then secondary vulcanization is performed at a temperature of 180°C for 30 min, and after cooling to room temperature, a silicone foam is obtained.

[0203] Example 2

[0204] The raw materials of the silicone foam of the present example include component A and component B in a weight ratio of 1:1.

[0205] Among them, component A is composed of the following raw materials: high-viscosity vinyl silicone oil 2.42%, low-viscosity vinyl silicone oil 33.85%, structure aid 0.97%, first base silicone resin mixture 3.38%, second base silicone resin mixture 49.81%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%, based on the total weight of component A being 100%.

[0206] Among them, component B is composed of the following raw materials: high-viscosity vinyl silicone oil 6.22%, low-viscosity vinyl silicone oil 37.71%, chain extender 2.07%, first base silicone resin mixture 16.58%, second base silicone resin mixture 31.08%, high-hydrogen silicone oil 6.22%, and silicon hydride addition inhibitor 0.12%, based on the total weight of component B being 100%.

[0207] The materials used for component A and component B are the same as in Example 1.

[0208] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as in Example 1.

[0209] The preparation method of the silicone foam of the present example is the same as in Example 1.

[0210] Example 3

[0211] The raw materials of the silicone foam of the present example include component A and component B in a weight ratio of 1:1.

[0212] Among them, component A is composed of the following raw materials: high-viscosity vinyl silicone oil 12.09%, low-viscosity vinyl silicone oil 24.18%, structure aid 0.97%, first base silicone resin mixture 14.51%, second base silicone resin mixture 38.68%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%, based on the total weight of component A being 100%.

[0213] consists of the following raw materials: high viscosity vinyl silicone oil 18.65%, low viscosity vinyl silicone oil 25.28%, chain extender 2.07%, first base silicone resin mixture 6.22%, second base silicone resin mixture 41.44%, high hydrogen-containing silicone oil 6.22%, and silicone hydride addition inhibitor 0.12%, based on 100% of the total weight of component B.

[0214] The materials used for component A and component B are the same as in Example 1.

[0215] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as in Example 1.

[0216] The method for preparing the silicone foam of this example is the same as in Example 1.

[0217] Example 4

[0218] This example provides a silicone foam, which raw materials include component A and component B in a weight ratio of 1:1;

[0219] wherein, based on 100% of the total weight of component A, it consists of the following raw materials: high viscosity vinyl silicone oil 5.80%, low viscosity vinyl silicone oil 31.43%, structure aid 0.48%, first base silicone resin mixture 7.25%, second base silicone resin mixture 48.36%, hydroxyl silicone oil 4.84%, platinum catalyst 1.45%, and colorant 0.39%;

[0220] consists of the following raw materials: high viscosity vinyl silicone oil 18.65%, low viscosity vinyl silicone oil 25.28%, chain extender 2.07%, first base silicone resin mixture 6.22%, second base silicone resin mixture 41.44%, high hydrogen-containing silicone oil 6.22%, and silicone hydride addition inhibitor 0.12%, based on 100% of the total weight of component B.

[0221] The materials used for component A and component B are the same as in Example 1.

[0222] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as in Example 1.

[0223] The method for preparing the silicone foam of this example is the same as in Example 1.

[0224] Example 5

[0225] This example provides a silicone foam, which raw materials include component A and component B in a weight ratio of 1:1;

[0226] wherein, based on the total weight of component A being 100%, it consists of the following raw materials: high viscosity vinyl silicone oil 4.84%, low viscosity vinyl silicone oil 31.43%, structure aid 1.45%, first base silicone resin mixture 7.25%, second base silicone resin mixture 41.59%, hydroxyl silicone oil 11.61%, platinum catalyst 1.45%, and color paste 0.39%;

[0227] wherein, based on the total weight of component B being 100%, it consists of the following raw materials: high viscosity vinyl silicone oil 12.85%, low viscosity vinyl silicone oil 31.91%, chain extender 1.24%, first base silicone resin mixture 12.43%, second base silicone resin mixture 34.81%, high hydrogen-containing silicone oil 6.63%, and silicone hydride addition inhibitor 0.12%.

[0228] The materials used in component A and component B are the same as in Example 1.

[0229] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as in Example 1.

[0230] The method for preparing the silicone foam of this example is the same as in Example 1.

[0231] Example 6

[0232] This example provides a silicone foam, which raw materials include component A and component B in a weight ratio of 1:1;

[0233] wherein, based on the total weight of component A being 100%, it consists of the following raw materials: high viscosity vinyl silicone oil 2.42%, low viscosity vinyl silicone oil 29.01%, structure aid 0.97%, first base silicone resin mixture 11.61%, second base silicone resin mixture 46.42%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%;

[0234] wherein, based on the total weight of component B being 100%, it consists of the following raw materials: high viscosity vinyl silicone oil 8.12%, low viscosity vinyl silicone oil 30.86%, chain extender 2.03%, first base silicone resin mixture 14.21%, second base silicone resin mixture 38.57%, high hydrogen-containing silicone oil 6.09%, and silicone hydride addition inhibitor 0.12%.

[0235] wherein the high viscosity vinyl silicone oil in component A and component B is HV-165000; the low viscosity vinyl silicone oil in component A and component B is HV-1000. Other components are the same as in Example 1.

[0236] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as in Example 1.

[0237] The preparation method of the silica gel foam of the present embodiment is the same as that of Example 1.

[0238] Example 7

[0239] The present embodiment provides a silica gel foam, the raw materials of which include component A and component B in a weight ratio of 1:1;

[0240] wherein, based on the total weight of component A being 100%, it is composed of the following raw materials: high-viscosity vinyl silicone oil 4.84%, low-viscosity vinyl silicone oil 31.43%, structure aid 0.97%, first base silicone resin mixture 7.25%, second base silicone resin mixture 45.94%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.38%;

[0241] based on the total weight of component B being 100%, it is composed of the following raw materials: high-viscosity vinyl silicone oil 12.18%, low-viscosity vinyl silicone oil 30.86%, chain extender 4.87%, first base silicone resin mixture 12.18%, second base silicone resin mixture 34.51%, high-hydrogen silicone oil 5.28%, and silicon-hydrogen addition inhibitor 0.12%;

[0242] wherein the chain extender is DY-H204; other components are the same as in component A and component B of Example 1.

[0243] wherein the reinforcing agent in the first base resin mixture is precipitated white carbon black with a specific surface area of 300 m 2 / g; other components of the first base silicone resin mixture and the second base silicone resin mixture and their contents are the same as in Example 1.

[0244] The viscosity of the first base silicone resin mixture is 800-900 thousand mpa·s. The viscosity of the second base silicone resin mixture is 30-40 thousand mpa·s.

[0245] The preparation method of the silica gel foam of the present embodiment is the same as that of Example 1.

[0246] Example 8

[0247] The present embodiment provides a silica gel foam, the raw materials of which include component A and component B in a weight ratio of 1:1;

[0248] wherein, based on the total weight of component A being 100%, it is composed of the following raw materials: high-viscosity vinyl silicone oil 4.84%, low-viscosity vinyl silicone oil 31.43%, structure aid 0.97%, first base silicone resin mixture 12.09%, second base silicone resin mixture 41.10%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%;

[0249] which consists of the following raw materials: high viscosity vinyl silicone oil 12.43%, low viscosity vinyl silicone oil 31.50%, chain extender 2.07%, first base silicone resin mixture 12.43%, second base silicone resin mixture 35.23%, high hydrogen-containing silicone oil 6.22%, and silicon hydride addition inhibitor 0.12%, based on 100% of the total weight of component B.

[0250] wherein the structural aid in component A is isopropyl alcohol, and the other components and example 1 are the same.

[0251] wherein the filler in the second base silicone resin mixture is calcium carbonate; the other components of the first base silicone resin mixture and the second base silicone resin mixture and their contents are the same as in example 1.

[0252] The viscosity of the first base silicone resin mixture is 90-100 million mpa·s. The viscosity of the second base silicone resin mixture is 40-50 million mpa·s.

[0253] The preparation method of the silicone foam of the present example is the same as that of example 1.

[0254] Comparative Example 1

[0255] The present comparative example provides a silicone foam, which raw materials include component A and component B in a weight ratio of 1:1;

[0256] wherein, based on 100% of the total weight of component A, it consists of the following raw materials: high viscosity vinyl silicone oil 4.84%, low viscosity vinyl silicone oil 31.43%, first base silicone resin mixture 7.25%, second base silicone resin mixture 46.91%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.38%;

[0257] which consists of the following raw materials: high viscosity vinyl silicone oil 12.43%, low viscosity vinyl silicone oil 31.50%, chain extender 2.07%, first base silicone resin mixture 12.43%, second base silicone resin mixture 35.23%, high hydrogen-containing silicone oil 6.22%, and silicon hydride addition inhibitor 0.12%, based on 100% of the total weight of component B.

[0258] The components of the first base silicone resin mixture and the second base silicone resin mixture and their contents are the same as in example 1.

[0259] The high viscosity vinyl silicone oil, low viscosity vinyl silicone oil, hydroxyl silicone oil, platinum catalyst, color paste, chain extender, high hydrogen-containing silicone oil, silicon hydride addition inhibitor, reinforcing agent, silazane, inorganic flame retardant, filler, and silane coupling agent are the same as in example 1.

[0260] The preparation method of the silica foam is basically the same as that of Example 1, except that the high-viscosity vinyl silicone oil and the low-viscosity vinyl silicone oil in the component A and the component B are not subjected to raw material pretreatment.

[0261] Comparative Example 2

[0262] The present comparative example provides a silica foam, the raw materials of which include component A and component B in a weight ratio of 1:1;

[0263] The component A, with a total weight of 100%, is composed of the following raw materials: high-viscosity vinyl silicone oil 4.84%, low-viscosity vinyl silicone oil 30.46%, structure aid 1.93%, first base silicone resin mixture 7.25%, second base silicone resin mixture 45.94%, hydroxyl silicone oil 7.74%, platinum catalyst 1.45%, and color paste 0.39%;

[0264] The component B, with a total weight of 100%, is composed of the following raw materials: high-viscosity vinyl silicone oil 12.43%, low-viscosity vinyl silicone oil 31.50%, chain extender 2.07%, first base silicone resin mixture 12.43%, second base silicone resin mixture 35.23%, high-hydrogen silicone oil 6.22%, and silicon-hydrogen addition inhibitor 0.12%;

[0265] The first base silicone resin mixture includes the following components in parts by weight: end-vinyl silicone oil with a viscosity of 1000 mpa·s 34 parts, end-vinyl silicone oil with a viscosity of 10000 mpa·s 60 parts, and reinforcing agent 5 parts;

[0266] The second base silicone resin mixture includes the following components in parts by weight: end-vinyl silicone oil with a viscosity of 20000 mpa·s 20 parts, end-vinyl silicone oil with a viscosity of 100000 mpa·s 24 parts, inorganic flame retardant 40 parts, and filler 15 parts.

[0267] The high-viscosity vinyl silicone oil, the low-viscosity vinyl silicone oil, the structure aid, the hydroxyl silicone oil, the platinum catalyst, the color paste, the chain extender, the high-hydrogen silicone oil, the silicon-hydrogen addition inhibitor, the reinforcing agent, the inorganic flame retardant, and the filler are the same as those of Example 1.

[0268] The preparation method of the silica foam is basically the same as that of Example 1, except that the end-vinyl silicone oil with a viscosity of 1000 mpa·s, the end-vinyl silicone oil with a viscosity of 10000 mpa·s, the end-vinyl silicone oil with a viscosity of 20000 mpa·s, and the end-vinyl silicone oil with a viscosity of 100000 mpa·s are not subjected to raw material pretreatment.

[0269] Comparative Example 3

[0270] The comparative example 1 provides a silica gel foam, which raw materials include component A and component B with a weight ratio of 1:1.

[0271] wherein, based on the total weight of component A being 100%, it is composed of the following raw materials: high viscosity vinyl silicone oil 4.84%, low viscosity vinyl silicone oil 31.43%, structural aid 0.29%, first base silicone resin mixture 7.25%, second base silicone resin mixture 40.81%, hydroxyl silicone oil 13.54%, platinum catalyst 1.45%, and color paste 0.39%;

[0272] based on the total weight of component B being 100%, it is composed of the following raw materials: high viscosity vinyl silicone oil 11.60%, low viscosity vinyl silicone oil 30.67%, chain extender 6.22%, first base silicone resin mixture 12.43%, second base silicone resin mixture 30.67%, high hydrogen-containing silicone oil 8.29%, and silicon hydride addition inhibitor 0.12%.

[0273] The components and their contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as those of example 1.

[0274] The high viscosity vinyl silicone oil, the low viscosity vinyl silicone oil, the structural aid, the hydroxyl silicone oil, the platinum catalyst, the color paste, the chain extender, the high hydrogen-containing silicone oil, the silicon hydride addition inhibitor, the reinforcing agent, the silazane, the inorganic flame retardant, the filler, and the silane coupling agent are the same as those of example 1.

[0275] The preparation method of the silica gel foam is the same as that of example 1.

[0276] Comparative example 4

[0277] The comparative example 1 provides a silica gel foam, which raw materials include component A and component B with a weight ratio of 1:1.

[0278] wherein, based on the total weight of component A being 100%, it is composed of the following raw materials: high viscosity vinyl silicone oil 4.84%, low viscosity vinyl silicone oil 24.66%, structural aid 0.97%, first base silicone resin mixture 7.25%, second base silicone resin mixture 45.94%, hydroxyl silicone oil 14.51%, platinum catalyst 1.45%, and color paste 0.39%;

[0279] based on the total weight of component B being 100%, it is composed of the following raw materials: high viscosity vinyl silicone oil 16.58%, low viscosity vinyl silicone oil 33.15%, chain extender 0.41%, first base silicone resin mixture 12.43%, second base silicone resin mixture 35.23%, high hydrogen-containing silicone oil 2.07%, and silicon hydride addition inhibitor 0.12%.

[0280] The components and contents of the first base silicone resin mixture and the second base silicone resin mixture are the same as those in Example 1.

[0281] The high-viscosity vinyl silicone oil, the low-viscosity vinyl silicone oil, the structure aid, the hydroxyl silicone oil, the platinum catalyst, the color paste, the chain extender, the high-hydrogen silicone oil, the hydrosilylation inhibitor, the reinforcing agent, the silazane, the inorganic flame retardant, the filler, and the silane coupling agent are all the same as those in Example 1.

[0282] The method for preparing the silicone foam of this example is basically the same as that in Example 1, except that the high-viscosity vinyl silicone oil and the low-viscosity vinyl silicone oil in Component A are not subjected to raw material pretreatment.

[0283] The evaluation results of the various characteristics, the outgassing property, and the resilience loss property of the silicone foams of the above examples and comparative examples are shown in Table 1.

[0284] Table 1

[0285]

[0286]

[0287] As can be seen from Table 1, the absolute value of the difference between the absorbances of the first characteristic peak and the second characteristic peak of the silicone foams provided by the comparative examples is not within the range of the present application, and / or the decay rate of the absorbance at a wave number of 1082 cm -1 in the Fourier transform infrared spectrum of the silicone foams before and after being placed in an environment at 180℃ for 4 hours is not within the range of the present application, so that these silicone foams cannot have both low outgassing property and low resilience loss property. The silicone foams of the examples of the present application have both low outgassing property and low resilience loss property, and are suitable for use in new energy battery cases, and can play the roles of buffering, waterproofing, sealing, and the like.

[0288] Obviously, the above examples of the present application are merely exemplary for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. For those skilled in the art, other different forms of changes or modifications can be made on the basis of the above description, and it is impossible to enumerate all the implementation modes here. Any changes or modifications that belong to the technical solutions of the present application and are derived from the present application still fall within the protection scope of the present application.

Claims

1. A type of silicone foam, wherein, In the Fourier transform infrared spectrum of the silicone foam, the absolute value of the difference in absorbance between the first characteristic peak and the second characteristic peak is greater than 0.02, and the first characteristic peak is located at wavenumbers of 861-865 cm⁻¹. -1 At this location, the second characteristic peak is located at wavenumbers of 910-920 cm⁻¹. -1 The silicone foam, after being placed in an environment of 180°C for 4 hours, exhibited the following Fourier transform infrared spectra at 1082 cm⁻¹: -1 The attenuation rate of the absorbance of the wavenumber is ≤3%.

2. The silicone foam according to claim 1, wherein, The silicone foam, after being compressed at 25% and placed in an environment at 100°C for 24 hours, then the compression was removed, and after being placed in a room temperature environment for 0.5 hours, had a 25% relative compression permanent deformation rate of less than 3%. The 25% relative compression permanent deformation rate was calculated using the following formula: P = T2 ÷ T1 × 100% Wherein, P is the 25% relative compression permanent deformation rate, %. T2 is the difference between the thickness of the silicone foam before compression and the thickness of the silicone foam after compression is removed and left at room temperature for 0.5 hours, in mm. T1 represents the thickness of the silicone foam before compression, in mm.

3. The silicone foam according to claim 1, wherein, The silicone foam, after being compressed at 70% and placed in an environment at 100°C for 24 hours, then the compression was removed, and after being placed in a room temperature environment for 0.5 hours, had a 70% relative compression permanent deformation rate of less than 5%. The 70% relative compression permanent deformation rate was calculated using the following formula: Q = R2 ÷ R1 × 100% Where Q is the 70% relative compression permanent deformation rate, %; R2 is the difference between the thickness of the silicone foam before compression and the thickness of the silicone foam after compression is removed and left at room temperature for 0.5 hours, in mm. R1 represents the thickness of the silicone foam before compression, in mm.

4. The silicone foam according to claim 1, wherein, The thickness decay rate of the silicone foam after one million compressions is ≤1.5%; The thickness attenuation rate of the silicone foam after one million compressions was obtained by testing it using the following method: the silicone foam was compressed from a compression rate of 0% to a compression rate of 50% and then the compression was removed, which was recorded as one compression. The compression frequency was 2.5Hz. After performing 1 million compressions, the thickness attenuation rate after one million compressions was tested.

5. The silicone foam according to claim 1, wherein, The silicone foam was subjected to a vacuum of 7×10⁻⁶ at 150°C. -3 After being placed in an environment of Pa for 24 hours, its mass loss rate is ≤1%, and the mass of the collectable condensate produced accounts for ≤0.5% of the mass of the silicone foam. The mass loss rate and the ratio of the mass of the collectable condensate to the mass of the silicone foam were obtained by the following methods: The silicone foam was pretreated by placing it in an environment of 23℃ and 50% relative humidity for 24 hours to obtain pretreated silicone foam; then the pretreated silicone foam was subjected to a vacuum of 150℃ and 7×10⁻⁶. -3 After being placed in an environment of Pa for 24 hours, the silicone foam was cooled to room temperature. Then, the silicone foam was pressurized to atmospheric pressure with a dry protective gas. The gas produced by the silicone foam was condensed and collected on a pre-weighed collection plate at a constant temperature of 25°C to obtain collectable condensate. The mass loss rate of the silicone foam and the mass ratio of the collectable condensate to the mass of the silicone foam were tested.

6. The silicone foam according to claim 5, wherein, The silicone foam was subjected to a vacuum of 7×10⁻⁶ at 150°C. -3 After being placed in an environment of Pa for 24 hours, its mass loss rate is 0.3%-0.9%, and the mass of the collectable condensate produced accounts for 0.1%-0.45% of the mass of the silicone foam.

7. The silicone foam according to claim 1, wherein, The silicone foam retains ≥80% of its compression rebound stress after compression for 1 minute and 30 minutes at room temperature within a compression range of 30%-80%.

8. The silicone foam according to claim 7, wherein, The silicone foam retains 90%-97% of its compression rebound stress after 1 minute of compression at room temperature within a compression range of 30%-80%, and 80%-90% of its compression rebound stress after 30 minutes of compression.

9. The silicone foam according to claim 1, wherein, The silicone foam, when placed in an environment of 85°C and 85% relative humidity under a compression rate of 50% for 1000 hours, then the compression is removed, and then placed in a room temperature environment for 0.5 hours, has a thickness change rate of ≤3%.

10. The silicone foam according to claim 9, wherein, The silicone foam, when placed in an environment of 85°C and 85% relative humidity under a compression rate of 50% for 1000 hours, and then the compression is removed and the foam is placed in a room temperature environment for 0.5 hours, has a thickness change rate of 0.2%-3%.

11. The silicone foam according to claim 1, wherein, The 25% compressive stress of the silicone foam is 50-200 kPa.

12. The silicone foam according to claim 1, wherein, The density of the silicone foam is 300-550 kg / m³. 3 .

13. The silicone foam according to claim 1, wherein, The thickness of the silicone foam is 0.5-16mm.

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