Organopolysiloxane composition containing a filler

Abstract

The present invention uses relatively high concentrations of D H The present invention relates to a composition comprising a first polyorganosiloxane functionalized with an OH group, a second polyorganosiloxane functionalized with an OH group or an ethylenically unsaturated group, a blowing agent, a filler, and a hydrosilylation catalyst. The composition of the present invention is useful for preparing low-density, high-filler foams useful as thermal barriers.

Description

[Technical Field]

[0001] The present invention relates to organopolysiloxane compositions having relatively high filler contents, which are useful as precursors for low density, high filler content foams for thermal barrier applications.

[0002] Polyorganosiloxane foams, such as polydimethylsiloxane (PDMS) foam, offer lower density and higher compressibility than comparable rigid materials. Filled PDMS foams offer additional benefits, such as flame retardancy, targeted (high or low) thermal conductivity, and more robust mechanical properties. Filled foams can be used as thermal barriers for rechargeable batteries, such as lithium-ion batteries (LiBs), commonly used in various applications, including electric vehicles (EVs). While LiBs offer desirable performance characteristics, such as high energy density and cycling stability, safety concerns currently limit their usefulness. First, LiB cell failure can be caused by manufacturing defects, internal short circuits, overheating, overcharging, or mechanical shock. Second, heat generated from a failed cell can propagate, potentially causing thermal runaway in adjacent cells. The rapid pressure buildup resulting from these thermal events increases the risk of fire and explosion.

[0003] Thermal events can be mitigated by placing thermal barriers between cells in a battery module that provide thermal insulation and flame resistance. Commonly used thermal barriers, such as aerogel, ceramic fiber, and mica board, offer such properties, but aerogel and ceramic fiber have poor mechanical resilience, while mica board has poor compressibility. Silicone blown foam, on the other hand, offers adequate compressibility and is therefore suitable for low- and medium-energy density batteries, but suffers from insufficient insulation to prevent thermal events in very high-energy density battery packs. Adding filler particles to the foam overcomes this drawback. However, the presence of fillers at useful levels disadvantageously increases the density of the foam.

[0004] Therefore, it would be advantageous in the field of thermal barriers to find a low density insulating barrier that has desirable thermal properties, flame retardancy, and other mechanical properties such as a high modulus of elasticity and greater mechanical strength. Summary of the Invention

[0005] In one aspect, the present invention provides a composition comprising: a) a degree of polymerization in the range of 5 to 200 and a D in the range of 60 to 100 mole percent H 2 to 50 weight percent of a first polyorganosiloxane having a concentration; b) 10 to 90 weight percent of a second polyorganosiloxane functionalized with at least two groups that are either ethylenically unsaturated groups or OH groups or a combination thereof, and having a degree of polymerization in the range of 50 to 2000; The concentrations of the first polyorganosiloxane and the second polyorganosiloxane are based on the weight of the first polyorganosiloxane and the second polyorganosiloxane, c) 0.1 to 20 weight percent of a blowing agent, based on the concentration of the first polyorganosiloxane and the second polyorganosiloxane and the blowing agent, including C1-C8 alcohols, C1-C8 diols, benzyl alcohol, HO—(CH2CHRO) z a blowing agent which is a polyorganosiloxane functionalized with —H, at least one OH group and having a degree of polymerization ranging from 1 to 15, or water, wherein R is H, methyl, or ethyl, and z is 2 to 5; d) 30 to 50 weight percent of one or more fillers, based on the weight of the composition, wherein the one or more fillers are selected from the group consisting of metals, metal oxides, metal hydroxides, metal acetates, metal carbides, metal oxycarbides, metal carbonates and bicarbonates, metal hydroxycarbonates, metal sulfates, metal chlorides, metal nitrides, metal nitrates, metal silicides, and metal silicates; e) a catalytic amount of a catalyst that promotes the reaction between the first polyorganosiloxane and the second polyorganosiloxane, and the first polyorganosiloxane and the blowing agent; D in the first polyorganosiloxane H and a catalyst, wherein the molar ratio of the hydroxyl groups to the ethylenically unsaturated and / or OH groups of the second polyorganosiloxane is in the range of 1.7:1 to 20:1.

[0006] The present invention addresses a need in the art by providing a method for preparing polyorganosiloxane foams having relatively low densities and relatively high filler contents. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram of a battery module including polyorganosiloxane foam material. DETAILED DESCRIPTION OF THE INVENTION

[0008] In one aspect, the present invention provides a composition comprising: a) a degree of polymerization in the range of 5 to 200 and a D in the range of 60 to 100 mole percent H 2 to 50 weight percent of a first polyorganosiloxane having a concentration; b) 10 to 90 weight percent of a second polyorganosiloxane functionalized with at least two groups that are either ethylenically unsaturated groups or OH groups or a combination thereof, and having a degree of polymerization in the range of 50 to 2000; The concentrations of the first polyorganosiloxane and the second polyorganosiloxane are based on the weight of the first polyorganosiloxane and the second polyorganosiloxane, c) 0.1 to 20 weight percent of a blowing agent, based on the concentration of the first polyorganosiloxane and the second polyorganosiloxane and the blowing agent, including C1-C8 alcohols, C1-C8 diols, benzyl alcohol, HO—(CH2CHRO) z a blowing agent which is a polyorganosiloxane functionalized with —H, at least one OH group and having a degree of polymerization ranging from 1 to 15, or water, wherein R is H, methyl, or ethyl, and z is 2 to 5; d) 30 to 50 weight percent of one or more fillers, based on the weight of the composition, wherein the one or more fillers are selected from the group consisting of metals, metal oxides, metal hydroxides, metal acetates, metal carbides, metal oxycarbides, metal carbonates and bicarbonates, metal hydroxycarbonates, metal sulfates, metal chlorides, metal nitrides, metal nitrates, metal silicides, and metal silicates; e) a catalytic amount of a catalyst that promotes the reaction between the first polyorganosiloxane and the second polyorganosiloxane, and the first polyorganosiloxane and the blowing agent; D in the first polyorganosiloxane H and a catalyst, wherein the molar ratio of the groups to the ethylenically unsaturated and / or OH groups of the second polyorganosiloxane is in the range of 1.7:1 to 20:1.

[0009] The first polyorganosiloxane is represented by Structure I:

[0010] [ka] In the formula, m is 0 to 80, and n is 5 to 200 or 100, provided that the ratio of m:n is in the range of 0:100 to 40:60, preferably up to 36:64. H The concentration is in the range of 60 mole percent or 64 mole percent to 100 mole percent. The first polyorganosiloxane has a weighted average D HIt is understood that there may be one or more polyorganosiloxanes having a concentration of D and D H It is further understood that the groups may be distributed in a random, block, or alternating manner.

[0011] The second polyorganosiloxane is at least one polyorganosiloxane functionalized with one or more OH groups, or one or more ethylenically unsaturated groups, or a combination of OH groups and ethylenically unsaturated groups. Preferably, the degree of polymerization of the second polyorganosiloxane is in the range of 100 to 1000.

[0012] The second polyorganosiloxane may further comprise a polyorganosiloxane resin functionalized with one or more OH groups, one or more ethylenically unsaturated groups, or a combination of OH groups and ethylenically unsaturated groups. The polyorganosiloxane resin may be a SiO 2 resin, as shown below. 3 / 2 Units or SiO 4 / 2 units or both.

[0013] [ka] In the formula, R o is methyl, ethyl, or phenyl, and the dashed line represents the point of attachment to another group. Examples of preferred second polyorganosiloxanes include divinyl polydimethylsiloxane, vinyl-substituted polyorganosiloxane resins, dihydroxy polydimethylsiloxane resins, and combinations thereof. The catalyst is preferably a platinum-based catalyst such as chloroplatinic acid, which is used in catalytic amounts, typically in the range of 0.5 ppm to 200 ppm Pt based on the weight of the composition.

[0014] D in the first polyorganosiloxane HThe mole to mole ratio of groups to hydroxyl and / or ethylenically unsaturated groups in the second polyorganosiloxane ranges from 1.7:1, or from 1.9:1, or from 3:1, or from 5:1, to 20:1, or to 15:1, or to 10:1. Preferably, the second polyorganosiloxane comprises ethylenically unsaturated groups, more preferably two vinyl groups.

[0015] The blowing agent reacts with the Si-H group in the presence of a Pt catalyst to generate H2 gas. Therefore, the blowing agent is C1-C8-alcohol, C1-C8-diol, benzyl alcohol, HO-(CH2CHRO) z -H (wherein R is H, methyl, or ethyl, and z is 2 to 5), or water. Examples of blowing agents include benzyl alcohol, ethanol, propanol, and 1,4-butanediol.

[0016] Fillers are metals, metal oxides, metal hydroxides, metal acetates, metal carbides, metal oxycarbides, metal carbonates and bicarbonates, metal hydroxycarbonates, metal sulfates, metal chlorides, metal nitrides, metal nitrates, metal silicides, metal silicates, and their hydrates, and mixtures thereof. Fillers are typically in the form of particles with average volume particle sizes ranging from 0.1 μm, 0.5 μm, or 1 μm to 1000 μm, 500 μm, 200 μm, 100 μm, or 50 μm, as measured using a dynamic light scattering analyzer such as a Beckman Coulter LS130 Particle Size Analyzer.

[0017] Examples of suitable fillers include aluminum trihydroxide, hydromagnesite, epsomite, neskihonite, boehmite, huntite, magnesium hydroxide, silica, crushed quartz, alumina, calcium sulfate, copper acetate, magnesium chloride, sodium sulfate, aluminosilicates, boron nitride, aluminum nitride, mica, wollastonite, calcium silicate, basalt, clays including calcined clay, zeolites, hollow fillers such as hollow glass spheres and hollow ceramics, expanded perlite, calcium carbonate, cesium oxide, iron oxide, titanium oxide, zinc oxide, and glass fibers, as well as hydrates of these fillers.

[0018] To achieve desired properties such as improved fire resistance and mechanical strength at elevated temperatures, it may be desirable to use high loadings of filler combinations. A particularly desirable filler combination is aluminum trihydroxide and wollastonite. The filler concentration, based on the weight of the composition, ranges from 30% by weight, preferably 35% by weight, to 50% by weight, preferably 45% by weight.

[0019] The composition is advantageously prepared in a two-part system. More specifically, the Pt catalyst is separated from the first polyorganosiloxane to prevent premature reaction between the first polyorganosiloxane and the second polyorganosiloxane and the blowing agent. In one preferred method of preparing the composition of the present invention, a first portion of the second polyorganosiloxane, the Pt catalyst, and the blowing agent are mixed in a first chamber. Then, a first portion of the filler is added to the contents of the first chamber and further mixed. In a second container, the first polyorganosiloxane is mixed with a second portion of the second polyorganosiloxane, followed by the addition of a second portion of the filler and further mixing. To facilitate mixing of the two parts, it is advantageous to include a filler in each chamber. The two parts are each dispensed onto the desired substrate or target area through a dispenser, typically a double-pack cartridge equipped with a static mixer. The reaction resulting from the release of hydrogen and the associated foaming begins after the first polyorganosiloxane contacts the second polyorganosiloxane and the blowing agent. The foam is advantageously cured at elevated temperatures, preferably at least 80°C or at least 100°C, preferably up to 200°C or up to 150°C.

[0020] The resulting foam contains residues of a blowing agent and residues of a second polyorganosiloxane, the latter being the product of reaction of Si-H groups from the first polyorganosiloxane with one or more OH groups of the blowing agent.

[0021] [ka] where R—Si—H is the first organopolysiloxane, R′—OH is the blowing agent, and O—R′ is the remainder of the blowing agent.

[0022] Similarly, the residue of the second polyorganosiloxane is the product of the reaction of the Si-H groups from the first polyorganosiloxane with the OH and / or ethylenically unsaturated groups of the second polyorganosiloxane. If the second polyorganosiloxane contains two ethylenically unsaturated groups, the residue is obtained from the following reaction:

[0023] [ka] where =-R''-Si is the second polyorganosiloxane and CH2CH2-R'' is the residue of the second polyorganosiloxane.

[0024] The foams produced from the compositions of the present invention surprisingly have high filler loadings (30-50 wt%) and foams with a filler content of 0.20 g / cm 3 , or 0.25 g / cm 3 ~0.60g / cm 3 , or ~0.52g / cm 3 , or ~0.40g / cm 3 Thus, in another aspect, the invention is a polyorganosiloxane foam having 30 to 50 weight percent filler particles interspersed therewith, based on the weight of the foam and filler particles, the foam further characterized by containing i) structural units of Si—H groups and blowing agent, and ii) structural units of Si—H groups and OH groups and / or ethylenically unsaturated groups, wherein the ratio of i:ii is in the range of 1.7:1 to 20:1 or to 15:1.

[0025] The foam is useful as a barrier material for battery module applications. In another aspect, the invention is a battery module comprising a shell containing an array of spatially separated battery cells and a composition of the invention in contact with adjacent battery cells.

[0026] FIG. 1 illustrates this embodiment of the present invention. The battery module includes a shell (20) containing an array of spatially separated battery cells (30 and 30a) and a barrier material (40) that contacts adjacent battery cells (30 and 30a) to form an insulating barrier between the battery cells (30 and 30a). In this embodiment, the barrier material is disposed between adjacent battery cells (30 and 30a). In another embodiment, the barrier material covers the battery cells. The battery module may further include end plates (50) on the interior edges of the shell that either directly contact the battery cells (not shown) or indirectly contact the battery cells (30a) via the barrier material (40). Barrier material can be inserted into the spaces between adjacent battery cells and between the cells and the end plates, or a foam precursor can be applied over the cells and into the spaces between the battery cells and then cured to form the barrier material. Examples of suitable battery cell designs include cylindrical cells, pouch cells, and prismatic cells. [Example]

[0027] In the following examples, pbw denotes parts by weight. All ingredients were mixed using a Flacktex speed mixer at 2000 rpm.

[0028] Comparative Intermediate Example 1 - Preparation of a Filler-Free Two-Part Composition The first component (Part A) is comprised of 1) a dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of about 1,900 mPa·s and 0.22 wt.% vinyl groups, and 2) ViMe2SiO 1 / 2 :(CH3)3Si-O 1 / 2 :SiO 4 / 2 Structural unit ratio 5:40:55, M n 5000, M w 21,400 ViMe2SiO 1 / 2 / (CH3)3Si-O 1 / 2 / SiO 4 / 2A 64:36 w / w blend of a) and b) a dimethylvinylsiloxy end-capped polydimethylsiloxane (Polymer 1, 13.63 pbw) with a viscosity of 40,000 mPa·s (Polymer 2, 78.11 pbw) was prepared by mixing for 30 seconds. A Pt(0) complex with divinyltetramethyldisiloxane (1.13 pbw, 0.62 pbw of Pt), 1,4-butanediol (3.14 pbw), and benzyl alcohol (4 pbw) were added to the mixture, and mixing was continued for another 30 seconds.

[0029] The second component (Part B) was prepared by mixing the polymer-resin blend (64.36 pbw) with Polymer 1 (11.23 pbw) for 30 seconds. H 79.31 M linear organohydrogenpolysiloxane (polymer 2, 17.95 pbw) and MD 3.2 D H 5.8 M of polydimethylorganohydrogensiloxane (Polymer 3, 6.46 pbw) was added to the mixture and mixing was continued for an additional 30 seconds.

[0030] Comparative Intermediate Example 2 - Contains filler, Si-H:vinyl ratio 6.23:1 and D H Preparation of a two-part composition with a mole percentage of 31.8% The first component (Part A) was prepared by mixing the polymer-resin blend (46.06 pbw), Polymer 1 (8.04 pbw), and Micral 855 aluminum hydroxide (10.8 pbw) for 30 seconds. Then, Pt(0) divinyltetramethyldisiloxane complex (0.66 wt%, 0.62 wt% Pt), 1,4-butanediol (1.85 pbw), and benzyl alcohol (2.36 pbw) were added to the mixture, and mixing was continued for 30 seconds. Imerys Nyad G wollastonite (30.23 pbw) was added to the mixture, and mixing was continued for another 30 seconds.

[0031] Polymer resin blend (20.11 pbw), Polymer 1 (3.51 pbw), and Hymod M855 aluminum hydroxide (10.41 pbw) were mixed for 30 seconds, followed by Polymer 3 (2.02 pbw) and MD 8.7 D H 3.7 Part B was prepared by adding M linear organohydrogenpolysiloxane (Polymer 4, 33.72 pbw). Mixing was continued for 30 seconds, after which Imerys Nyad G wollastonite (30.23 pbw) was added to the mixture and mixing was continued for an additional 30 seconds.

[0032] Comparative Intermediate Example 3 - Contains filler, Si-H:vinyl ratio 1.48:1, D H Preparation of a 21.5% two-part composition: The first component (Part A) was prepared by mixing the polymer-resin blend (18.75 pbw) with dimethylvinylsiloxy end-capped polydimethylsiloxane (Polymer 5, 50.9 pbw) having a viscosity of approximately 2,200 mPa·s for 30 seconds. Pt(0) divinyltetramethyldisiloxane complex (0.64 pbw, 0.62 pbw Pt) and benzyl alcohol (7.72 pbw) were added to the mixture. The contents were mixed for 30 seconds, after which Imerys Nyad G wollastonite (14.39 pbw) and Minusil 5 silica (5 μm, 7.6 pbw) were added to the mixture, and mixing was continued for an additional 30 seconds.

[0033] Part B was prepared by mixing the polymer resin blend (18.75 pbw) with Polymer 5 (47.58 pbw) for 30 seconds. Polymer 4 (6.68 pbw) and linear organohydrogenpolysiloxane MD 60 D H 7M (Polymer 6, 5 pbw) was added to the mixture and the contents were mixed at 2000 rpm for 30 seconds. Imerys Nyad G wollastonite (14.39 pbw) and Minusil 5 silica (5 μm, 7.6 pbw) were then added to the mixture and mixing was continued for an additional 30 seconds.

[0034] Intermediate Example 1 - Filled, Si-H:vinyl ratio 1.94:1, D H Preparation of a 90.6% two-part composition The first component (Part A) was prepared by mixing the polymer-resin blend (45.53 pbw), Polymer 1 (7.94 pbw), and Micral 855 aluminum hydroxide (10.68 pbw) for 30 seconds. Then, Pt(0) divinyltetramethyldisiloxane complex (0.66 pbw, 0.62 pbw Pt), 1,4-butanediol (1.82 pbw), and benzyl alcohol (2.33 pbw) were added to the mixture, and mixing was continued for 30 seconds. Imerys Nyad G wollastonite (31.03 pbw) was added to the mixture, and mixing was continued for another 30 seconds.

[0035] The second composition (Part B) was prepared by mixing the polymer-resin blend (48.27 pbw), Polymer 1 (3.91 pbw), and Hymod M855 aluminum hydroxide (11.59 pbw) for 30 seconds. Polymer 2 (2.93 pbw) and Polymer 3 (2.25 pbw) were then added to the mixture, and the contents were mixed for 30 seconds. Imerys Nyad G wollastonite (31.03 pbw) was added to the mixture, and mixing was continued for an additional 30 seconds.

[0036] Table 1 summarizes the formulations of Part A and Part B in pbw. PRB refers to polymer-resin blend. P1-P6 refer to polymers 1-6. BDO refers to 1,4-butanediol. BzOH refers to benzyl alcohol. Pt refers to Pt(0) complex. F1 refers to Micral 855 ATH filler. F2 refers to Hymod M855-SP filler. F3 refers to Nyad G wollastonite filler, and F4 refers to Minus 1L 5 silica.

[0037] [Table 1]

[0038] Table 2 illustrates additional Part A and Part B formulations used to prepare compositions of the present invention. F5 refers to mica WG-325 muscovite mica.

[0039] [Table 2]

[0040] Foam sheet manufacturing All foam sheets were produced using the following procedure: Parts A and B were thoroughly mixed for 15 seconds. The mixture was then poured between two matte Mylar film sheets. The initial (pre-foaming) thickness was controlled at 0.045 inches using nip rollers. The samples were then transferred to an oven set at 120°C. After 2 minutes, the release film sheet was removed and the samples were allowed to cure continuously at 120°C. Foam density was calculated based on the average thickness and weight of two 1-inch (2.54 cm) diameter foam samples.

[0041] Table 3 shows the calculated D H Mole percent (D H %=D H m / (D H m +D n ), D of the blend of Part A and Part B when mixed H The ratio of vinyl groups to vinyl groups (D H : vinyl), filler concentration (filler%), foam density (g / cm 3 ) (density), and foam uniformity (foam). U refers to uniform foam, and NU refers to non-uniform foam.

[0042] [Table 3]

[0043] Table 3 shows the D H : vinyl group ratio and D H By adjusting the concentration, the polyorganosiloxane composition can be obtained with a density of less than 0.6 g / cm 3The data show that foams with a density and filler concentration of over 30% can be achieved. The data also suggest that low density, high filler concentration foams are achievable with a variety of filler materials. Surprisingly, the unfilled foam (C1) was found to be non-uniform, resulting in poor thickness control and poor compressibility.

[0044] The relatively high ratio of Si-H groups to vinyl or SiOH groups, coupled with the relatively high concentration of Si-H groups in the first polyorganosiloxane, results in higher H2 gas production, thus resulting in greater expansion and therefore lower foam density, and simultaneously lower crosslink density. Surprisingly, the high concentration of filler aids in the production of uniform foams despite the higher H2 gas production.

Claims

1. 1. A composition comprising: a) a degree of polymerization in the range of 5 to 200 and a D in the range of 60 to 100 mole percent Ｈ 2 to 50 weight percent of a first polyorganosiloxane having a concentration of b) 10 to 90 percent by weight of a second polyorganosiloxane functionalized with at least two groups that are either ethylenically unsaturated groups or OH groups or a combination thereof and having a degree of polymerization in the range of 50 to 2000; A second polyorganosiloxane, wherein the concentrations of the first polyorganosiloxane and the second polyorganosiloxane are based on the weight of the first polyorganosiloxane and the second polyorganosiloxane; c) 0.1 to 20 weight percent of a blowing agent, based on the concentration of the first polyorganosiloxane and the second polyorganosiloxane and the blowing agent, １ ~C ８ -alcohol, C １ ~C ８ -diol, benzyl alcohol, HO-(CH ２ CHRO) ｚ a blowing agent which is a polyorganosiloxane functionalized with —H, at least one OH group and having a degree of polymerization ranging from 1 to 15, or water, wherein R is H, methyl, or ethyl, and z is 2 to 5; d) 30 to 50 weight percent of one or more fillers, based on the weight of the composition, said one or more fillers being selected from the group consisting of metals, metal oxides, metal hydroxides, metal acetates, metal carbides, metal oxycarbides, metal carbonates and bicarbonates, metal hydroxycarbonates, metal sulfates, metal chlorides, metal nitrides, metal nitrates, metal silicides, and metal silicates; e) a catalytic amount of a catalyst that promotes the reaction between the first polyorganosiloxane and the second polyorganosiloxane, and the first polyorganosiloxane and the blowing agent; D in the first polyorganosiloxane Ｈ and a catalyst, wherein the molar to molar ratio of said second polyorganosiloxane to said ethylenically unsaturated and / or OH groups is in the range of 1.7:1 to 20:

1.

2. The first polyorganosiloxane has a degree of polymerization in the range of 5 to 100 and a D in the range of 64 to 100 mole percent. Ｈ concentration, and D in the first polyorganosiloxane Ｈ 2. The composition of claim 1, wherein the molar to molar ratio of groups to the ethylenically unsaturated groups and / or OH groups in the second polyorganosiloxane ranges from 1.7:1 to 15:

1.

3. 3. The composition of claim 2, wherein the second polyorganosiloxane is one or more polyorganosiloxanes functionalized with two ethylenically unsaturated groups.

4. The ethylenically unsaturated group is a vinyl group, and the blowing agent is C １ ~C ８ -alcohol, C １ ~C ８ 4. The composition of claim 3, wherein the catalyst is one or more fillers selected from the group consisting of aluminum trihydroxide, hydromagnesite, epsomite, nesquihonite, boehmite, huntite, magnesium hydroxide, silica, ground quartz, alumina, calcium sulfate, copper acetate, magnesium chloride, sodium sulfate, aluminosilicates, boron nitride, aluminum nitride, mica, wollastonite, calcium silicate, basalt, clay, zeolite, hollow glass spheres, hollow ceramics, expanded perlite, calcium carbonate, cesium oxide, iron oxide, titanium oxide, zinc oxide, and glass fiber; and the catalyst is a platinum catalyst.

5. 5. The composition of claim 4, wherein the second polyorganosiloxane further comprises a vinyl-substituted polyorganosiloxane resin.

6. 6. The composition of claim 5, wherein the concentration of the filler ranges from 35 to 55 weight percent based on the weight of the total composition and the filler, the blowing agent is benzyl alcohol, or 1,4-butanediol, or a combination thereof, and the filler is a combination of wollastonite and aluminum trihydroxide.

7. D in the first polyorganosiloxane Ｈ 4. The composition of claim 3, wherein the molar to molar ratio of alkyl groups to the ethylenically unsaturated groups in the second polyorganosiloxane ranges from 3:1 to 10:1, the blowing agent is benzyl alcohol, or 1,4-butanediol, or a combination thereof, the filler is a combination of wollastonite and aluminum trihydroxide, and the second polyorganosiloxane comprises a divinylpolymethylsiloxane and a divinylpolymethylsiloxane resin.

8. D in the first polyorganosiloxane Ｈ 7. The composition of claim 6, wherein the molar to molar ratio of groups to ethylenically unsaturated groups in the second polyorganosiloxane ranges from 3:1 to 10:1, the blowing agent is benzyl alcohol or 1,4-butanediol, and the filler is a combination of wollastonite and aluminum trihydroxide.

9. 3. The composition of claim 2, wherein the second polyorganosiloxane is functionalized with one ethylenically unsaturated group and one OH group, or is functionalized with two OH groups.

10. Components a), b), c), and d) react to form a density of 0.20 to 0.60 g / cm ３ 10. The composition of claim 1, which forms a foam having a density in the range of

11. The foam has a density of 0.25 g / cm ３ ~0.52 g / cm ３ and a filler concentration in the range of 35 to 55 wt. % based on the weight of the foam and the filler.

12. A battery module comprising a shell containing an array of spatially separated battery cells, and the composition of any one of claims 1 to 8 in contact with adjacent battery cells.

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