A liquid foamable silicone rubber composition and a method for producing a foam silicone rubber elastomer thereof

Abstract

The application discloses a liquid foam silicone rubber composition and a preparation method of foam silicone rubber elastomer thereof, which is composed of A component and B component in mass fractions: the A component is composed of base A, base B, base C, structure control agent, foaming agent, base polymer and platinum gold catalyst; the B component is composed of base A, base B, base C, base polymer, crosslinking agent and inhibitor; wherein, the base A is composed of base polymer, reinforcing filler and treatment agent D; the base B is composed of base polymer, flame-retardant filler and treatment agent E; and the base C is composed of base polymer, heavy filler and treatment agent F. The A component and the B component are prepared separately, then the A component and the B component are mixed according to the mass fraction ratio of 1:1, and then the foam silicone rubber elastomer is obtained by curing at 45-100 DEG C for 10-20 min. The liquid foam silicone rubber has good fluidity and process operability, the foam silicone rubber elastomer obtained after curing has uniform and delicate cell structure, has good mechanical properties and flame-retardant properties, and can be widely used in the fields of new energy automobile battery pack coating, high-speed train floor support, outdoor communication, sealing and protection of electronic and lighting equipment cabinets and the like.

Description

Technical Field

[0001] This invention relates to an organopolysiloxane composition, specifically to a liquid foamed silicone rubber composition and a method for preparing the foamed silicone rubber elastomer, belonging to the field of polymer materials technology. Background Technology

[0002] Foamed silicone rubber is a new type of porous, multifunctional, and environmentally friendly polymer elastomer made from silicone rubber through a foaming process. It not only possesses the excellent properties of silicone rubber products, such as non-toxicity, heat resistance, weather resistance, and good electrical insulation, but also exhibits the properties of foam materials such as vibration damping, sound insulation, heat insulation, sealing, and lightweight. It is widely used in defense, transportation, electronics industry, building decoration, aerospace, and other fields.

[0003] Chinese patent CN105331112A discloses a method for preparing graphene-silicone rubber composite foam material, the steps of which are as follows: (1) Prepare a composite material of graphene and silicone rubber raw rubber; (2) Mix the composite material at 100-120℃, adding silica and structure control agent alternately in batches during mixing. After the addition is completed, continue mixing for 15-20 minutes to remove the volatiles in the resulting mixture and cool it to room temperature. Let it stand for 10-14 hours, then add vulcanizing agent and mix at room temperature for 15-30 minutes to obtain a compound; (3) Pre-vulcanize the compound at 120-125℃ and form it into a preform. Place the preform in a reaction vessel for supercritical carbon dioxide foaming to obtain a pre-vulcanized foam material; (4) Completely vulcanize the pre-vulcanized foam material to obtain the final product. This method involves supercritical carbon dioxide foaming technology, which is expensive. Furthermore, the use of solvents such as cyclohexane, dichloromethane, tetrahydrofuran, and toluene in the preparation of the graphene-silicone rubber composite material generates a large amount of waste liquid, causing environmental pollution.

[0004] Chinese patent CN106433139A discloses a low-density, high-porosity silicone rubber foam material and its preparation method. The method involves mixing 100 parts silicone rubber, 10-50 parts reinforcing agent, 1-7 parts control agent, 200-600 parts pore-forming agent, and 0-5 parts sensitizer, followed by molding and cross-linking via gamma-ray radiation. The resulting material is then dissolved and freeze-dried to obtain the low-density, high-porosity silicone rubber foam material. This method is complex and cumbersome, requires sophisticated equipment, and is difficult to implement for continuous industrial production.

[0005] Chinese patent CN113831738A discloses an addition-type liquid silicone rubber foam material and its preparation method. The foaming component consists of 40-90 parts vinyl silicone oil, 2-10 parts hydroxyl silicone oil, 0.03-0.12 parts platinum catalyst, 1-16 parts silica, and 15-60 parts flame-retardant filler; the crosslinking component consists of 10-70 parts vinyl silicone oil, 20-90 parts hydrogen-containing silicone oil, 1-30 parts silica, and 1-30 parts flame-retardant filler. To prevent the foaming and crosslinking components from vulcanizing and foaming at room temperature after mixing, the chosen solution is to mix the foaming and crosslinking components at -20 to -10°C. This inevitably increases the manufacturing cost of freezing the rubber compound, limiting large-scale industrial production.

[0006] With the rapid development of my country's rail transit, new energy vehicles, outdoor communications, and electronics industries, traditional foam materials (such as polyurethane foam) are finding it increasingly difficult to meet market performance demands. Liquid foam silicone rubber, due to its superior properties such as environmental friendliness, lightweight, and weather resistance, will gradually replace traditional foam materials. However, my country's production technology for liquid foam silicone rubber is still in its early stages, and there is still a considerable distance to go before large-scale continuous production can be achieved. Therefore, it is essential to realize the continuous large-scale production of liquid foam silicone rubber and to prepare foam silicone rubber elastomer materials with uniform cell structure, high resilience, and flame retardancy that meet market demands, which is of significant research and development importance. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a liquid foamed silicone rubber composition and a method for preparing the foamed silicone rubber elastomer thereof. This liquid foamed silicone rubber exhibits good flowability and processability. The cured foamed silicone rubber elastomer possesses a uniform and fine cell structure, excellent mechanical properties and flame retardant properties, and can be widely used in fields such as battery pack encapsulation for new energy vehicles, floor support for high-speed trains, sealing and protection of outdoor communication, electronic, and lighting equipment cabinets. Furthermore, this method features a simple preparation process, suitable for continuous large-scale production.

[0008] This invention is achieved through the following technical solution: a liquid foam silicone rubber composition, comprising component A and component B in parts by mass:

[0009] Component A: Base material A 100 parts, Base material B 60-130 parts, Base material C 45-145 parts, Structure control agent 10-35 parts, Foaming agent 2-10 parts, Basic polymer 10-55 parts, Platinum catalyst 0.5-2 parts;

[0010] Component B: 100 parts of base material A, 60-130 parts of base material B, 45-145 parts of base material C, 10-65 parts of base polymer, 22-45 parts of crosslinking agent, and 0.001-0.01 parts of inhibitor;

[0011] In either component A or component B mentioned above,

[0012] The composition of the base material A is: 100 parts of base polymer, 40-50 parts of reinforcing filler, and 12-22 parts of treatment agent D;

[0013] The composition of the base material B is: 100 parts of base polymer, 100-300 parts of flame retardant filler, and 1-3 parts of treatment agent E;

[0014] The composition of the base material C is: 100 parts of base polymer, 50-100 parts of heavy filler, and 0-3 parts of treatment agent F.

[0015] Adding a base polymer and a treatment agent to the three base materials to form a paste can treat the surface of the filler and increase its compatibility.

[0016] Furthermore, the structure control agent is a branched polysiloxane with a vinyl content of 1.5–4.5% by mass, and its structure is shown in formula (Ⅰ) below:

[0017] [(Me)3SiO 1 / 2 ] a [Vi(Me)SiO 2 / 2 ] b [SiO 4 / 2 ] c (I)

[0018] Where a, b, and c are all natural numbers greater than 1;

[0019] Furthermore, the crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.0–1.6%, and its structure is shown in formula (II) below:

[0020] (HMe2SiO 1 / 2 )2(HMeSiO) m (Me2SiO) n (II)

[0021] Where m is a natural number greater than 1, and n is a natural number greater than or equal to 0;

[0022] Furthermore, the base polymer is a linear polysiloxane with a vinyl content of 0.08–0.3% by mass, and its structure is shown in formula (Ⅲ) below:

[0023] (ViMe2SiO 1 / 2 )2(ViMeSiO) m (Me2SiO) n (III)

[0024] Where m is a natural number ≥ 0 and n is a natural number > 1.

[0025] Furthermore, the foaming agent is an organic alcohol having 1-12 carbon atoms and one hydroxyl functional group per molecule, such as methanol, ethanol, propanol, isopropanol, n-butanol, dodecyl alcohol, etc.; or an organic alcohol having 2-6 carbon atoms and two hydroxyl functional groups per molecule, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,2-hexanediol, or any mixture of one or more.

[0026] Furthermore, the platinum catalyst is a complex of chloroplatinic acid and vinylsiloxane.

[0027] Further, the inhibitor is one or more of tetravinyltetramethylcyclotetrasiloxane, tetramethyldivinyldisiloxane, methylbutynol, acetylenol, and 3,7,11-trimethyl-1-dodecyn-3-ol.

[0028] Furthermore, in the aforementioned base material A, the reinforcing filler is selected from materials with a specific surface area of ​​200 m². 2 / g、250m 2 / g、300m 2 / g、380m 2 / g、400m 2 / g of precipitated silica or fumed silica, which is one or more of them in a mixture.

[0029] Furthermore, in the aforementioned base material B, the flame-retardant filler is selected from aluminum hydroxide, magnesium hydroxide, magnesium oxide, and aluminum oxide, and is a mixture of one or more of these.

[0030] Furthermore, in the aforementioned base material C, the heavy filler is selected from diatomaceous earth, wollastonite, and silica powder, and is a mixture of one or more of them.

[0031] Furthermore, in the base material A described above, the treatment agent D is one or more of hexamethyldisilazane, octamethylcyclotetrasiloxane, and γ-glycidoxypropyltrimethoxysilane.

[0032] Furthermore, in the base material B described above, the treatment agent E is one or more of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane, or a mixture thereof.

[0033] Furthermore, in the base material C mentioned above, the treatment agent F is one or a mixture of two of vinyltris(2-methoxyethoxy)silane and 3-aminopropyltriethoxysilane.

[0034] The method for preparing foamed silicone rubber elastomer from the above-mentioned liquid foamed silicone rubber composition includes the following steps:

[0035] I. Preparation of Base Material

[0036] (1) Preparation of base material A

[0037] Weigh each material according to the mass fraction, add treatment agent D and reinforcing filler to the base polymer, stir evenly, heat to 150℃, vacuum degree ≥0.08MPa, and continue stirring for 2-4 hours to obtain base material A;

[0038] (2) Preparation of base material B

[0039] Weigh each material according to the mass fraction, add treatment agent E and flame retardant filler to the base polymer, stir evenly, heat to 120-150℃, vacuum degree ≥0.08MPa, and continue stirring for 1-2.5h to obtain base material B;

[0040] (3) Preparation of base material C

[0041] Weigh each material according to the mass fraction, add treatment agent F and heavy filler to the base polymer, stir evenly, heat to 100-120℃, vacuum degree ≥0.08MPa, and continue stirring for 0.5-2h to obtain base material C;

[0042] II. Preparation of Components A and B

[0043] (1) Preparation of component A

[0044] Weigh each material according to the mass fractions, and add base material A, base material B, base material C, structure control agent, foaming agent, basic polymer and platinum catalyst into the mixer in sequence. Mix at room temperature for 1 hour to obtain component A.

[0045] (2) Preparation of component B

[0046] Weigh each material according to the mass fractions, and add base material A, base material B, base material C, base polymer, crosslinking agent and inhibitor into the mixer in sequence. Mix at room temperature for 1 hour to obtain component B.

[0047] III. Preparation of Foamed Silicone Rubber Elastomers

[0048] First, weigh components A and B in a 1:1 mass ratio, mix them thoroughly in a static or dynamic mixer, and then spray them between two release films. Then, control the initial thickness of the rubber compound through a calendering process. Finally, it enters the drying tunnel through a conveyor belt and is foamed and cured at 45-100℃ for 10-20 minutes to obtain foamed silicone rubber elastomer sheets.

[0049] Scanning electron microscopy (SEM) images and performance test results show that the foamed silicone rubber elastomer obtained by mixing and curing components A and B of this invention has a pore size of 130–350 µm and a density of 0.25–0.45 g / cm³. 3 It has a tensile strength of 315–450 kPa, an elongation of 66–105%, a compressive stress of 62–105 kPa, a compression set of 0.52–1.2%, a water absorption rate of ≤0.75%, and a flame retardancy of V-0. The foam structure is uniform and delicate, with good mechanical and flame retardant properties, which can fully meet the needs of market applications.

[0050] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0051] (1) In the liquid foam silicone rubber composition of the present invention, the base material A prepared by 100 parts of base polymer, 12 to 22 parts of treatment agent D and 40 to 50 parts of reinforcing filler can not only effectively support the foam cells and stabilize the foam, but also greatly improve the storage stability of the A and B components.

[0052] (2) The foaming and curing process of liquid foam silicone rubber material is similar to the crystallization process, which requires the generation of bubble nuclei and the growth of bubble bodies. In the liquid foam silicone rubber composition of the present invention, the base material C prepared by 100 parts of base polymer and 50 to 100 parts of heavy filler is beneficial to the formation of bubble nuclei and the growth of bubble bodies, so that the foam silicone rubber elastomer prepared in the end has uniform and delicate pores.

[0053] (3) The mechanical and flame-retardant properties of the liquid foam silicone rubber of the present invention not only fully consider the filling amount and ratio of various fillers, but also effectively improve the resilience and compression deformation properties of the foam silicone rubber elastomer by selecting a concentrated cross-linking network structure formed by polysiloxanes with different structures. Specifically, the structure control agent uses branched polysiloxanes with a vinyl mass percentage of 1.5 to 4.5%, and the cross-linking agent is linear polysiloxane with a hydrogen mass percentage of 1.0 to 1.6%. The concentrated cross-linking network structure formed by the combination of two polysiloxanes with different compositions has a significant effect on improving the resilience and compression deformation properties of the foam silicone rubber elastomer.

[0054] (4) This invention does not contain substances such as nitrogen, phosphorus, sulfur, organotin and heavy metals that can poison platinum catalysts. At the same time, by selecting inhibitors and controlling the amount, the competitive relationship between foaming speed and curing speed during the foaming and curing process can be effectively solved, so that components A and B can have good fluidity and a longer operating time after being mixed at room temperature, which is conducive to continuous industrial production. Attached Figure Description

[0055] Figure 1Here is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Example 1;

[0056] Figure 2 Here is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Example 2;

[0057] Figure 3 This is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Example 3;

[0058] Figure 4 Here is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Example 4;

[0059] Figure 5 Here is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Example 5;

[0060] Figure 6 This is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Comparative Example 1;

[0061] Figure 7 This is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Comparative Example 2;

[0062] Figure 8 This is a scanning electron microscope image of the foamed silicone rubber elastomer prepared in Comparative Example 3;

[0063] Figure 9 These are scanning electron microscope images of the foamed silicone rubber elastomers prepared in Comparative Examples 4 and 5.

[0064] Figure 10 This is a product image of the foamed silicone rubber elastomer sheet of the present invention. Detailed Implementation

[0065] To better explain the present invention, the present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0066] Example 1

[0067] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0068] Component A: Base material A 100 parts, Base material B 100 parts, Base material C 100 parts, Structure control agent 15 parts, Foaming agent 5 parts, Basic polymer 25 parts, Platinum catalyst 1.0 part;

[0069] Component B: 100 parts of base material A, 80 parts of base material B, 120 parts of base material C, 30 parts of base polymer, 25 parts of crosslinking agent, and 0.001 parts of inhibitor;

[0070] in,

[0071] The structure control agent is a branched polysiloxane with a vinyl content of 3% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 34 [SiO 4 / 2 ] 448 ;

[0072] The base polymer is a linear polysiloxane with a vinyl content of 0.3% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)4(Me2SiO) 803 ;

[0073] The foaming agent is n-hexanol;

[0074] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0075] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.6%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 23 (Me2SiO)0;

[0076] The inhibitor is methylbutynol;

[0077] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.1% by mass) and reinforcing filler (with a specific surface area of ​​200 m²). 2 40 parts of fumed silica (g / g) and 12 parts of treatment agent D (γ-glycidoxypropyltrimethoxysilane);

[0078] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.1%), 100 parts of flame retardant filler (aluminum hydroxide), and 1 part of treatment agent E (methyltrimethoxysilane).

[0079] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.1%), 50 parts of heavy filler (wollastonite), and 1 part of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0080] Preparation of base material A: Weigh each material according to the mass fraction, add treatment agent D and reinforcing filler to the base polymer, stir evenly, heat to 150℃, vacuum degree ≥0.08MPa, and continue stirring for 2-4 hours to obtain base material A;

[0081] Preparation of base material B: Weigh each material according to the mass fraction, add treatment agent E and flame retardant filler to the base polymer, stir evenly, heat to 120-150℃, vacuum degree ≥0.08MPa, and continue stirring for 1-2.5h to obtain base material B;

[0082] Preparation of base material C: Weigh each material according to the mass fraction, add treatment agent F and heavy filler to the base polymer, stir evenly, heat to 100-120℃, vacuum degree ≥0.08MPa, and continue stirring for 0.5-2h to obtain base material C;

[0083] Preparation of Component A: Weigh each material according to the mass fractions, and add base material A, base material B, base material C, structure control agent, foaming agent, base polymer and platinum catalyst into a mixer in sequence. Mix at room temperature for 1 hour to obtain component A.

[0084] Preparation of Component B: Weigh each material according to the mass fractions, and add base material A, base material B, base material C, base polymer, crosslinking agent and inhibitor to the mixer in sequence. Mix at room temperature for 1 hour to obtain component B.

[0085] First, weigh components A and B in a 1:1 mass ratio, mix them thoroughly in a static or dynamic mixer, and then spray them between two layers of release film. Next, control the initial thickness of the compound using a calendering process. Finally, convey the compound through a conveyor belt into a drying tunnel and cure it at 60°C for 20 minutes to obtain the foamed silicone rubber elastomer sheet (see product details for sheet). Figure 10 The elastomer underwent relevant performance tests (mechanical properties, flame retardancy, water absorption, and cell structure, etc.), and the results are listed in Table 1. The scanning electron microscope image of the elastomer is shown below. Figure 1 As shown.

[0086] Example 2

[0087] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0088] Component A: Base material A 100 parts, Base material B 60 parts, Base material C 50 parts, Structure control agent 20 parts, Foaming agent 4.5 parts, Basic polymer 52 parts, Platinum catalyst 1.0 part;

[0089] Component B: 100 parts of base material A, 105 parts of base material B, 64 parts of base material C, 55 parts of basic polymer, 32 parts of crosslinking agent, and 0.003 parts of inhibitor;

[0090] in,

[0091] The structure control agent is a branched polysiloxane with a vinyl content of 2.6% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]4[Vi(Me)SiO 2 / 2] 43 [SiO 4 / 2 ] 683 ;

[0092] The base polymer is a linear polysiloxane with a vinyl content of 0.08% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)6(Me2SiO) 3504 ;

[0093] The foaming agent is dodecyl alcohol;

[0094] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0095] The catalyst and inhibitor are the same as in Example 1;

[0096] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.08% by mass) and reinforcing filler (with a specific surface area of ​​300 m²). 2 40 parts of fumed silica ( / g) and 20 parts of treatment agent D (hexamethyldisilazane);

[0097] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.08%), 100 parts of flame retardant filler (magnesium hydroxide), and 1 part of treatment agent E (methyltrimethoxysilane).

[0098] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.08%), 50 parts of heavy filler (silicon micro powder), and 1 part of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0099] Following the same method as in Example 1, base materials A, B, and C were prepared separately first, followed by the preparation of components A and B. Finally, components A and B were mixed in a 1:1 mass ratio using a dynamic mixer and sprayed between two release films. The initial thickness of the compound was controlled by a calendering process. The compound was then conveyed into a drying tunnel and foamed and cured at 45°C for 20 minutes to obtain the foamed silicone rubber elastomer sheet. Relevant performance tests (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) were performed on the elastomer, and the results are listed in Table 1. The scanning electron microscope image of the elastomer is shown below. Figure 2 As shown.

[0100] Example 3

[0101] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0102] Component A: Base material A 100 parts, Base material B 75 parts, Base material C 92 parts, Structure control agent 12 parts, Foaming agent 6 parts, Basic polymer 48 parts, Platinum catalyst 1.5 parts;

[0103] Component B: 100 parts of base material A, 70 parts of base material B, 88 parts of base material C, 33 parts of basic polymer, 40 parts of crosslinking agent, and 0.01 parts of inhibitor;

[0104] in,

[0105] The structure control agent is a branched polysiloxane with a vinyl content of 4.2% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 50 [SiO 4 / 2 ] 459 ;

[0106] The base polymer is a linear polysiloxane with a vinyl content of 0.2% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)0(Me2SiO) 363 ;

[0107] The foaming agent is 1,3-propanediol;

[0108] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.0%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 35 (Me2SiO) 20 ;

[0109] The catalyst and inhibitor are the same as in Example 1;

[0110] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.2% by mass) and reinforcing filler (with a specific surface area of ​​300 m²). 2 45 parts of fumed silica ( / g) and 22 parts of treatment agent D (octamethylcyclotetrasiloxane);

[0111] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.2%), 200 parts of flame retardant filler (alumina), and 2 parts of treatment agent E (methyltriethoxysilane).

[0112] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.2%), 50 parts of heavy filler (diatomaceous earth), and 1 part of treatment agent F (3-aminopropyltriethoxysilane).

[0113] Foamed silicone rubber elastomer sheets were prepared using the same method as in Example 1. The test results for the relevant properties of the elastomer (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) are listed in Table 1. A scanning electron microscope image of the elastomer is shown below. Figure 3 As shown.

[0114] Example 4

[0115] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0116] Component A: Base material A 100 parts, Base material B 130 parts, Base material C 45 parts, Structure control agent 35 parts, Foaming agent 10 parts, Basic polymer 55 parts, Platinum catalyst 1.5 parts;

[0117] Component B: 100 parts of base material A, 130 parts of base material B, 45 parts of base material C, 65 parts of base polymer, 35 parts of crosslinking agent, and 0.004 parts of inhibitor;

[0118] in,

[0119] The structure control agent is a branched polysiloxane with a vinyl content of 4.5% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 42 [SiO 4 / 2 ] 357 ;

[0120] The base polymer is a linear polysiloxane with a vinyl content of 0.15% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)2(Me2SiO) 969 ;

[0121] The foaming agent is ethylene glycol;

[0122] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0123] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0124] The inhibitor is 3,7,11-trimethyl-1-dodecyn-3-ol;

[0125] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.15% by mass) and reinforcing filler (with a specific surface area of ​​380 m²). 2 40 parts of fumed silica ( / g) and 22 parts of treatment agent D (hexamethyldisilazane);

[0126] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.15% by mass), 100 parts of flame retardant filler (aluminum hydroxide), and 2.5 parts of treatment agent E (methyltriethoxysilane).

[0127] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.15%), 75 parts of heavy filler (diatomaceous earth), and 2 parts of treatment agent F (3-aminopropyltriethoxysilane).

[0128] Following the same method as in Example 1, base materials A, B, and C were prepared separately first, followed by the preparation of components A and B. Finally, components A and B were mixed in a 1:1 mass ratio using a dynamic mixer and sprayed between two release films. The initial thickness of the compound was controlled by a calendering process. The compound was then conveyed into a drying tunnel and foamed and cured at 80°C for 20 minutes to obtain the foamed silicone rubber elastomer sheet. Relevant performance tests (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) were performed on the elastomer, and the results are listed in Table 1. The scanning electron microscope image of the elastomer is shown below. Figure 4 As shown.

[0129] Example 5

[0130] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0131] Component A: Base material A 100 parts, Base material B 82 parts, Base material C 77 parts, Structure control agent 25 parts, Foaming agent 5 parts, Basic polymer 51 parts, Platinum catalyst 1.25 parts;

[0132] Component B: 100 parts of base material A, 110 parts of base material B, 48 parts of base material C, 18 parts of base polymer, 30 parts of crosslinking agent, and 0.006 parts of inhibitor;

[0133] in,

[0134] The structure control agent is a branched polysiloxane with a vinyl content of 3.7% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 24 [SiO 4 / 2] 255 ;

[0135] The base polymer is a linear polysiloxane with a vinyl content of 0.12% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)1(Me2SiO) 908 ;

[0136] The foaming agent is 1,4-butanediol;

[0137] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0138] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0139] The inhibitor is acetylenecycloethanol;

[0140] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.12% by mass) and reinforcing filler (with a specific surface area of ​​400 m²). 2 40 parts of fumed silica ( / g) and 22 parts of treatment agent D (hexamethyldisilazane);

[0141] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.12%), 150 parts of flame retardant filler (magnesium oxide), and 1.5 parts of treatment agent E (vinyltrimethoxysilane).

[0142] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.12%), 75 parts of heavy filler (diatomaceous earth), and 2 parts of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0143] Following the same method as in Example 1, base materials A, B, and C were prepared separately first, followed by the preparation of components A and B. Finally, components A and B were mixed in a 1:1 mass ratio using a dynamic mixer and sprayed between two release films. The initial thickness of the compound was controlled by a calendering process. The mixture was then conveyed into a drying tunnel and foamed and cured at 100°C for 10 minutes to obtain the foamed silicone rubber elastomer sheet. Relevant performance tests (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) were performed on the elastomer, and the results are listed in Table 1. The scanning electron microscope image of the elastomer is shown below. Figure 5 As shown.

[0144] Example 6

[0145] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0146] Component A: Base material A 100 parts, Base material B 86 parts, Base material C 60 parts, Structure control agent 32 parts, Foaming agent 5 parts, Basic polymer 40 parts, Platinum catalyst 1.75 parts;

[0147] Component B: 100 parts of base material A, 80 parts of base material B, 130 parts of base material C, 48 parts of basic polymer, 35 parts of crosslinking agent, and 0.0045 parts of inhibitor;

[0148] in,

[0149] The structure control agent is a branched polysiloxane with a vinyl content of 2.0% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 21 [SiO 4 / 2 ] 439 ;

[0150] The base polymer is a linear polysiloxane with a vinyl content of 0.18% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)0(Me2SiO) 403 ;

[0151] The foaming agent is n-butanol;

[0152] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0153] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0154] The inhibitor is a mixture of tetravinyltetramethylcyclotetrasiloxane and acetylenecycloethanol in a mass ratio of 1:1;

[0155] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.18% by mass) and reinforcing filler (with a specific surface area of ​​300 m²). 2 50 parts of fumed silica ( / g) and 20 parts of treatment agent D (hexamethyldisilazane);

[0156] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 200 parts of flame retardant filler (aluminum hydroxide), and 2 parts of treatment agent E (vinyltrimethoxysilane).

[0157] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 75 parts of heavy filler (diatomaceous earth), and 2 parts of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0158] Foamed silicone rubber elastomer sheets were prepared using the same method as in Example 4. The test results for the relevant properties of the elastomer (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) are listed in Table 1.

[0159] Example 7

[0160] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0161] Component A: Base material A 100 parts, Base material B 65 parts, Base material C 145 parts, Structure control agent 10 parts, Foaming agent 2 parts, Base polymer 10 parts, Platinum catalyst 0.5 parts;

[0162] Component B: 100 parts of base material A, 60 parts of base material B, 145 parts of base material C, 10 parts of basic polymer, 22 parts of crosslinking agent, and 0.008 parts of inhibitor;

[0163] in,

[0164] The structure control agent is a branched polysiloxane with a vinyl content of 1.5% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ]9[SiO 4 / 2 ] 254 ;

[0165] The base polymer is a linear polysiloxane with a vinyl content of 0.3% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)8(Me2SiO) 1204 ;

[0166] The foaming agent is methanol;

[0167] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0168] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0169] The inhibitor is a mixture of methylbutynol and ethynylcycloethanol in a mass ratio of 1:2;

[0170] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.18% by mass) and reinforcing filler (with a specific surface area of ​​250 m²). 2 50 parts of fumed silica ( / g) and 18 parts of treatment agent D (hexamethyldisilazane);

[0171] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 300 parts of flame retardant filler (aluminum hydroxide), and 3 parts of treatment agent E (vinyltrimethoxysilane).

[0172] The composition of the base material C is: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%) and 100 parts of heavy filler (diatomaceous earth).

[0173] Foamed silicone rubber elastomer sheets were prepared using the same method as in Example 4. The test results for the relevant properties of the elastomer (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) are listed in Table 1.

[0174] Example 8

[0175] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0176] Component A: Base material A 100 parts, Base material B 90 parts, Base material C 90 parts, Structure control agent 15 parts, Foaming agent 5.5 parts, Basic polymer 50 parts, Platinum catalyst 1.6 parts;

[0177] Component B: 100 parts of base material A, 80 parts of base material B, 80 parts of base material C, 42 parts of basic polymer, 45 parts of crosslinking agent, and 0.009 parts of inhibitor;

[0178] in,

[0179] The structure control agent is a branched polysiloxane with a vinyl content of 4.0% by mass, and its structural formula is [(Me)3SiO]. 1 / 2 ]2[Vi(Me)SiO 2 / 2 ] 18 [SiO 4 / 2 ] 174 ;

[0180] The base polymer is a linear polysiloxane with a vinyl content of 0.18% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)0(Me2SiO) 403 ;

[0181] The foaming agent is hexanediol;

[0182] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0183] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0184] The inhibitor is acetylenecycloethanol;

[0185] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.18% by mass) and reinforcing filler (with a specific surface area of ​​300 m²). 2 45 parts of fumed silica ( / g) and 15 parts of treatment agent D (hexamethyldisilazane);

[0186] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 200 parts of flame retardant filler (aluminum hydroxide), and 2 parts of treatment agent E (vinyltrimethoxysilane).

[0187] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 60 parts of heavy filler (diatomaceous earth), and 1.5 parts of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0188] Foamed silicone rubber elastomer sheets were prepared using the same method as in Example 4. The test results for the relevant properties of the elastomer (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) are listed in Table 1.

[0189] Example 9

[0190] A liquid foam silicone rubber composition comprising the following components A and B in parts by mass:

[0191] Component A: Base material A 100 parts, Base material B 85 parts, Base material C 55 parts, Structure control agent 28 parts, Foaming agent 8 parts, Basic polymer 48 parts, Platinum catalyst 2.0 parts;

[0192] Component B: 100 parts of base material A, 95 parts of base material B, 140 parts of base material C, 20 parts of base polymer, 40 parts of crosslinking agent, and 0.01 parts of inhibitor;

[0193] in,

[0194] The structure control agent is a branched polysiloxane with a vinyl content of 3.5% by mass, and its structural formula is [(Me)3SiO2]. 1 / 2 ]2[Vi(Me)SiO2 / 2 ] 15 [SiO 4 / 2 ] 168 ;

[0195] The base polymer is a linear polysiloxane with a vinyl content of 0.18% by mass, and its structural formula is (ViMe2SiO). 1 / 2 )2(ViMeSiO)0(Me2SiO) 403 ;

[0196] The foaming agent is isopropanol;

[0197] The catalyst is a complex of chloroplatinic acid and vinylsiloxane;

[0198] The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.5%, and its structural formula is (HMe2SiO). 1 / 2 )2(HMeSiO) 28 (Me2SiO)3;

[0199] The inhibitor is acetylenecycloethanol;

[0200] The composition of the base material A is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl content of 0.18% by mass) and reinforcing filler (with a specific surface area of ​​300 m²). 2 40 parts of fumed silica ( / g) and 17.5 parts of treatment agent D (hexamethyldisilazane);

[0201] The composition of the base material B is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 200 parts of flame retardant filler (aluminum hydroxide), and 2 parts of treatment agent E (methyltriethoxysilane).

[0202] The composition of the base material C is as follows: 100 parts of base polymer (linear polysiloxane with a vinyl mass percentage of 0.18%), 80 parts of heavy filler (diatomaceous earth), and 2.5 parts of treatment agent F (vinyltris(2-methoxyethoxy)silane).

[0203] Foamed silicone rubber elastomer sheets were prepared using the same method as in Example 4. The test results for the relevant properties of the elastomer (mechanical properties, flame retardancy, water absorption, and cell structure, etc.) are listed in Table 1.

[0204]

[0205] From the test results in Table 1 and Figures 1-5 It can be seen that the foamed silicone rubber elastomer obtained by mixing and curing components A and B of the present invention has a pore size of 130–350 µm and a density of 0.25–0.45 g / cm³.3 The tensile strength is 315–450 kPa, elongation is 66–105%, compressive stress is 62–105 kPa, compression set is 0.52–1.2%, water absorption is ≤0.75%, and flame retardancy is V-0. This foamed silicone rubber elastomer not only has a uniform and fine cell structure, but also possesses excellent mechanical and flame-retardant properties, meeting market performance requirements.

[0206] The present invention will be further described below with reference to comparative examples.

[0207] Comparative Example 1

[0208] Based on Example 1, this comparative example adjusts the specific surface area of ​​fumed silica in base material A. In this comparative example, 40 parts have a specific surface area of ​​180 m². 2 / g of fumed silica as a substitute Example 1: 40 parts of base A have a specific surface area of ​​200m². 2 / g of fumed silica, with the remaining formulation components and preparation method being the same as in Example 1. The performance of the foamed silicone rubber elastomers prepared in this comparative example and Example 1 was tested, and the results are shown in Table 2; the scanning electron microscope image of the foamed silicone rubber elastomer of Comparative Example 1 is shown below. Figure 6 .

[0209]

[0210] From Table 2 and Figure 6 It can be seen that: the specific surface area of ​​fumed silica changed from 200 m² in Example 1 to... 2 / g decreased to 180m in Comparative Example 1 2 / g, due to the deterioration of the reinforcing effect, it will have a significant adverse impact on the cell structure, density, mechanical properties, water absorption, and other properties of the foamed silicone rubber elastomer. In Comparative Example 1, the cell structure of the foamed silicone rubber elastomer becomes coarse and uneven, with a density reaching 0.82 g / cm³. 3 For foam materials, although tensile strength and elongation increase with increasing density, market applications primarily value lower density, better compression set, lower water absorption, and more uniform cell structure. High elongation and high tensile strength are not necessarily the best indicators, as the mechanical properties of foam materials are generally quite low (below 1 MPa). Furthermore, when the density of a foam material exceeds 0.5 g / cm³... 3 None of them have any practical market value.

[0211] Comparative Example 2

[0212] This comparative example is based on Example 6, except that the heavy filler in base material C is replaced with 75 parts of calcium carbonate, while the remaining formulation components and preparation method are the same as in Example 6. The performance of the foamed silicone rubber elastomers prepared in this comparative example and Example 6 was tested, and the results are shown in Table 3. The scanning electron microscope image of the foamed silicone rubber elastomer of Comparative Example 2 is shown below. Figure 7 .

[0213]

[0214] From Table 3 and Figure 7 It can be seen that: the composition of the heavy filler in the single-variable base material C is changed from diatomaceous earth in Example 6 to calcium carbonate in Comparative Example 2. Since calcium carbonate cannot play a nucleating role in the foaming and molding process of liquid foam silicone rubber, it will significantly increase the pore size of the foam silicone rubber elastomer, which will also lead to a decrease in the mechanical and water absorption properties of the elastomer.

[0215] Comparative Example 3

[0216] Based on Example 4, this comparative example adjusted the vinyl content of the structure control agent in component A. In this comparative example, branched polysiloxane with a vinyl content of 1.35% by mass was added as a structure control agent; the remaining formulation components and preparation method were the same as in Example 4. The performance of the foamed silicone rubber elastomers prepared in this comparative example and Example 4 was tested, and the results are shown in Table 4. The scanning electron microscope image of the foamed silicone rubber elastomer of Comparative Example 3 is shown below. Figure 8 .

[0217]

[0218] From Table 4 and Figure 8 It can be seen that when the vinyl content of the single variable structure control agent is changed from 4.5% in Example 4 to 1.35% in Comparative Example 3, the concentrated cross-linked network structure is greatly reduced, resulting in poorer resilience of the foamed silicone rubber elastomer and a significant increase in compression set.

[0219] Comparative Example 4

[0220] This comparative example is based on Example 9, but the amount of platinum catalyst in component A is adjusted. In this comparative example, 0.45 parts of platinum catalyst are added, while the remaining formulation components and preparation method are the same as in Example 9. The performance of the foamed silicone rubber elastomers prepared in this comparative example and Example 9 is tested, and the results are shown in Table 5. The scanning electron microscope image of the foamed silicone rubber elastomer of Comparative Example 4 is shown below. Figure 9 .

[0221]

[0222] From Table 5 and Figure 9It can be seen that: by simply changing the amount of platinum catalyst, from 2.0 parts of platinum catalyst in Example 9 to 0.45 parts in Comparative Example 4, the foaming speed of the liquid foam silicone rubber will be faster than the curing speed during the foaming and curing process. That is, gas is released in the early stage of the reaction, and at the same time, the viscosity of the liquid foam silicone rubber is insufficient to retain the gas, resulting in cell collapse and a significant increase in cell size.

[0223] Comparative Example 5

[0224] This comparative example is based on Example 9, but the amount of inhibitor in component B is adjusted. In this comparative example, 0.012 parts of acetylenecycloethanol are added; the remaining formulation components and preparation method are the same as in Example 9. The performance of the foamed silicone rubber elastomers prepared in this comparative example and Example 9 is tested, and the results are shown in Table 6. The scanning electron microscope image of the foamed silicone rubber elastomer of Comparative Example 5 is shown below. Figure 9 .

[0225]

[0226] From Table 6 and Figure 9 It can be seen that increasing the amount of single-variation inhibitor from 0.01 parts of acetylenecyclohexanol in Example 9 to 0.012 parts in Comparative Example 5 will cause the liquid foam silicone rubber to cure at a slower rate than the foaming rate during the foaming process. That is, gas is released in the early stage of the reaction, and the viscosity of the liquid foam silicone rubber is insufficient to retain the gas, resulting in cell collapse and a significant increase in cell size.

[0227] In summary, factors such as the specific surface area of ​​silica, the type of heavy filler, the vinyl content of the structure control agent, the platinum catalyst, and the amount of inhibitor all significantly affect the mechanical properties and cell structure of foamed silicone rubber elastomers. This invention innovatively uses a structure control agent and a cell structure control filler, ensuring that the liquid foamed silicone rubber possesses good flowability and workability while achieving relatively ideal mechanical properties and cell structure.

[0228] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A liquid foam silicone rubber composition, characterized in that, It consists of the following components A and B in parts by mass: Component A: Base material A 100 parts, Base material B 60-130 parts, Base material C 45-145 parts, Structure control agent 10-35 parts, Foaming agent 2-10 parts, Basic polymer 10-55 parts, Platinum catalyst 0.5-2 parts; Component B: 100 parts of base material A, 60-130 parts of base material B, 45-145 parts of base material C, 10-65 parts of base polymer, 22-45 parts of crosslinking agent, and 0.001-0.01 parts of inhibitor; The composition of the base material A is: 100 parts of base polymer, 40-50 parts of reinforcing filler, and 12-22 parts of treatment agent D; The composition of the base material B is: 100 parts of base polymer, 100-300 parts of flame retardant filler, and 1-3 parts of treatment agent E; The composition of the base material C is: 100 parts of base polymer, 50-100 parts of heavy filler, and 0-3 parts of treatment agent F; The structure control agent is a branched polysiloxane with a vinyl content of 1.5-4.5% by mass, and its structure is shown in formula (I) below: [(Me)3SiO 1 / 2 ] a [Vi(Me)SiO 2 / 2 ] b [SiO 4 / 2 ] c (I) Where a, b, and c are all natural numbers greater than 1; The crosslinking agent is a linear polysiloxane with a hydrogen mass percentage of 1.0–1.6%, and its structure is shown in formula (II) below: (HMe2SiO 1 / 2 )2(HMeSiO) m (Me2SiO) n (II) Where m is a natural number greater than 1, and n is a natural number greater than or equal to 0; The base polymer is a linear polysiloxane with a vinyl content of 0.08–0.3% by mass, and its structure is shown in formula (III) below: (ViMe2SiO 1 / 2 )2(ViMeSiO) m (Me2SiO) n (III) Where m is a natural number ≥ 0 and n is a natural number > 1; In the aforementioned base material A, the reinforcing filler is selected from materials with a specific surface area of ​​200 m². 2 / g、250m 2 / g、300m 2 / g、380m 2 / g、400m 2 / g of precipitated silica or fumed silica, which is one or more of them in a mixture; In the base material C mentioned above, the heavy filler is selected from diatomaceous earth, wollastonite, and silica powder, and is a mixture of one or more of them; In the base material A above, the treatment agent D is one or a mixture of hexamethyldisilazane, octamethylcyclotetrasiloxane, and γ-glycidoxypropyltrimethoxysilane; in the base material B above, the treatment agent E is one or a mixture of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; in the base material C above, the treatment agent F is one or a mixture of two of vinyltris(2-methoxyethoxy)silane and 3-aminopropyltriethoxysilane.

2. The liquid foam silicone rubber composition according to claim 1, characterized in that, The foaming agent is an organic alcohol having 1-12 carbon atoms and one hydroxyl functional group per molecule, or an organic alcohol having 2-6 carbon atoms and two hydroxyl functional groups per molecule, or any mixture of one or more of these.

3. The liquid foam silicone rubber composition according to claim 1, characterized in that, The platinum catalyst is a complex of chloroplatinic acid and vinylsiloxane.

4. The liquid foam silicone rubber composition according to claim 1, characterized in that, The inhibitor is one or more of tetravinyltetramethylcyclotetrasiloxane, tetramethyldivinyldisiloxane, methylbutynol, ethynylcycloethanol, and 3,7,11-trimethyl-1-dodecyn-3-ol.

5. The liquid foam silicone rubber composition according to claim 1, characterized in that, In the base material B mentioned above, the flame-retardant filler is selected from aluminum hydroxide, magnesium hydroxide, magnesium oxide, and aluminum oxide, and is a mixture of one or more of them.

6. A method for preparing a foamed silicone rubber elastomer from a liquid foamed silicone rubber composition according to claim 1, characterized in that, Includes the following steps: I. Preparation of Base Material (1) Preparation of base material A Weigh each material according to the mass fraction, add treatment agent D and reinforcing filler to the base polymer, stir evenly, heat to 150℃, vacuum degree ≥0.08MPa, and continue stirring for 2-4 hours to obtain base material A; (2) Preparation of base material B Weigh each material according to the mass fraction, add treatment agent E and flame retardant filler to the base polymer, stir evenly, heat to 120-150℃, vacuum degree ≥0.08MPa, and continue stirring for 1-2.5h to obtain base material B; (3) Preparation of base material C Weigh each material according to the mass fraction, add treatment agent F and heavy filler to the base polymer, stir evenly, heat to 100-120℃, vacuum degree ≥0.08MPa, and continue stirring for 0.5-2h to obtain base material C; II. Preparation of Components A and B (1) Preparation of component A Weigh each material according to the mass fractions, and add base material A, base material B, base material C, structure control agent, foaming agent, basic polymer and platinum catalyst into the mixer in sequence. Mix at room temperature for 1 hour to obtain component A. (2) Preparation of component B Weigh each material according to the mass fractions, and add base material A, base material B, base material C, base polymer, crosslinking agent and inhibitor into the mixer in sequence. Mix at room temperature for 1 hour to obtain component B. III. Preparation of Foamed Silicone Rubber Elastomers First, weigh components A and B in a 1:1 mass ratio, mix them thoroughly in a static or dynamic mixer, and then spray them between two release films. Then, control the initial thickness of the rubber compound through a calendering process. Finally, it enters the drying tunnel through a conveyor belt and is foamed and cured at 45-100℃ for 10-20 minutes to obtain foamed silicone rubber elastomer sheets.

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