Silicone rubber laminates for sealing materials, sealing materials, and batteries

Abstract

To provide a silicone rubber laminate for sealants that has improved flame retardancy compared to the conventional art and can maintain elongation even after combustion.SOLUTION: A silicone rubber laminate for sealants (1) according to one embodiment of the present invention comprises a first layer (1a) comprising a first flame-retardant silicone rubber compound, and a second layer (1b) comprising a second flame-retardant silicone rubber compound and a fibrous flame retardant. When the content of the second flame-retardant silicone rubber compound is 100 pts.wt., the content of the fibrous flame retardant is 5-60 pts.wt.; and the second flame-retardant silicone rubber compound has V-0 or higher in accordance with the UL94 standard.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , ,

[0001] The present invention relates to a silicone rubber laminate for a sealing material, a sealing material, and a battery.

Background Art

[0002] Conventionally, in order to impart industrially desirable physical properties, compositions in which various additives are added to silicone rubber have been proposed (see, for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when silicone rubber is adopted for a sealing material used in a battery, it is preferable to impart flame retardancy to the silicone rubber. As a result of investigations by the present inventors, it has been found that there is still room for improving the flame retardancy and maintaining the elongation after combustion in existing flame-retardant silicone rubber compounds.

[0005] One aspect of the present invention aims to provide a silicone rubber laminate for a sealing material that has improved flame retardancy compared to the prior art and can maintain elongation even after combustion.

Means for Solving the Problems

[0006] In order to solve the above problems, a silicone rubber laminate for a sealing material according to one aspect of the present invention includes a first layer containing a first flame-retardant silicone rubber compound, A second layer containing a second flame-retardant silicone rubber compound and a fiber-based flame retardant, It is equipped with, If the content of the above-mentioned second flame-retardant silicone rubber compound is 100 parts by weight, then the content of the above-mentioned fiber-based flame retardant is 5 to 60 parts by weight. The above-mentioned second flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. [Effects of the Invention]

[0007] According to one aspect of the present invention, a silicone rubber laminate for sealing materials is provided that has improved flame retardancy compared to conventional materials and maintains its elongation even after combustion. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an example of the general structure of a silicone rubber laminate for sealing material according to one aspect of the present invention. [Figure 2] This is a schematic diagram showing another example of the general structure of a silicone rubber laminate for sealing material according to one aspect of the present invention. [Figure 3] This is a schematic diagram showing another example of the general structure of a silicone rubber laminate for sealing material according to one aspect of the present invention. [Figure 4] This is a schematic diagram showing another example of the general structure of a silicone rubber laminate for sealing material according to one aspect of the present invention. [Figure 5] This is a schematic diagram showing an example of a battery using a sealing material according to one aspect of the present invention. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below, and various modifications are possible within the scope described. Embodiments that appropriately combine the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0010] In this specification, "A~B" representing a numerical range means "greater than or equal to A, and less than or equal to B."

[0011] ≪1. Silicone rubber laminate for sealing materials≫ Figure 1 is a schematic diagram showing an example of the general structure of a silicone rubber laminate for sealing material according to one aspect of the present invention. The silicone rubber laminate for sealing material 10 (sealing material 10) comprises a first layer 1 and a second layer 2. The second layer 2 and the first layer 1 will be described below in that order.

[0012] [1.1.Second layer] The second layer contains a second flame-retardant silicone rubber compound and a fiber-based flame retardant. The individual components are described below.

[0013] [1.1.1. Second Flame-Retardant Silicone Rubber Compound] The second flame-retardant silicone rubber compound is a composition in which various additives are blended with silicone rubber to impart flame retardancy. The second flame-retardant silicone rubber compound has a flame retardancy of V-0 or higher according to the UL94 standard.

[0014] The UL94 standard is a globally adopted standard for evaluating the flame retardancy of plastic products. The UL94 standards, in order of increasing flame retardancy, include 5VA, 5VB, V-0, V-1, V-2, and HB. Therefore, the second flame-retardant silicone rubber compound is classified as 5VA, 5VB, or V-0 according to the UL94 standard. In one embodiment, the second flame-retardant silicone rubber compound is classified as V-0 according to the UL94 standard. The UL94 test method is well known to those skilled in the art and therefore will not be described.

[0015] Examples of silicone rubbers included in the second flame-retardant silicone rubber compound include methyl silicone rubber, vinyl methyl silicone rubber, phenyl methyl silicone rubber, and fluorinated silicone rubber. Only one of these silicone rubbers may be included, or two or more may be included. In one embodiment, the second flame-retardant silicone rubber compound contains vinyl methyl silicone rubber. Examples of additives included in the second flame-retardant silicone rubber compound include platinum, platinum compounds, iron oxide, triazole-based compounds, and aluminum hydroxide. Only one of these additives may be included, or two or more may be included. There are many commercially available silicone rubber compounds corresponding to the second flame-retardant silicone rubber compound, and there are also many related patent documents. Therefore, the detailed composition of the second flame-retardant silicone rubber compound will be omitted from the description.

[0016] Examples of commercially available products corresponding to the second flame-retardant silicone rubber compound include SILASTIC (TM) SH502U, SH502U A / B, SH1447 U A (all from Dow Corning Toray Co., Ltd.); KE-5620W-U, KE-5620BL-U, KE-5612E-U, KE-3494, KE3490, KE3467, KE-4890, KE-40RTV, KE-1831, KE-1867, KE-1891, KE-1204-LTV, KE-1292, KE-1800, KE-1802 (all from Shin-Etsu Chemical Co., Ltd.); ELASTOSIL (R) LR 3011 / 50 FR, LR 3001 / 55 FR, LR 3001 / 60 FR, LR 3170 / 40 (all from Asahi Kasei Wacker Silicone Co., Ltd.); TSE2186U, TSE218, TSE2187U, TSE2184U, TCM5406U, XE20-A7016 (all from Momentive Performance Materials Japan LLC).

[0017] Examples of patent documents that disclose silicone rubber compounds corresponding to the second flame-retardant silicone rubber compound include JP-A-2004-149693, JP-A-2006-182911, and JP-A-2009-144024.

[0018] [1.1.2. Fiber-based flame retardants] A fiber-based flame retardant represents a flame retardant having a fibrous form. In this specification, the "fibrous form" is intended to mean a shape having an aspect ratio (length / diameter) of 3 or more.

[0019] According to the findings of the present inventors, a silicone rubber laminate provided with a second layer in which a second flame-retardant silicone rubber compound and a fiber-based flame retardant are combined has improved flame retardancy compared to the second flame-retardant silicone rubber compound itself. However, the effect of improving flame retardancy was not observed even when a flame retardant other than the fiber-based flame retardant (such as a phosphorus-based flame retardant) was blended (see the examples of the present application for details). That is, it can be said that the effect of the present invention has been manifested by selecting a fiber-based flame retardant among various types of flame retardants.

[0020] The lower limit of the average fiber length of the fiber-based flame retardant is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 100 μm or more. The upper limit of the average fiber length of the fiber-based flame retardant is preferably 1500 μm or less, more preferably 1000 μm or less, and even more preferably 800 μm or less. The lower limit of the average diameter of the fiber-based flame retardant is preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.15 μm or more, and particularly preferably 0.2 μm or more. The upper limit of the average diameter of the fiber-based flame retardant is preferably 10.0 μm or less, more preferably 5.0 μm or less, even more preferably 3.0 μm or less, and particularly preferably 1.0 μm or less. The lower limit of the aspect ratio is preferably 5 or more, more preferably 50 or more, even more preferably 100 or more, and particularly preferably 150 or more. The upper limit of the aspect ratio is preferably 5000 or less, more preferably 4000 or less, even more preferably 1000 or less, particularly preferably 500 or less, and even more preferably 250 or less.

[0021] Examples of fiber-based flame retardants include artificial mineral fibers and natural mineral fibers. Examples of artificial mineral fibers include rock wool, stone wool, slag wool, mineral wool, glass wool, and mineral glass wool. Examples of natural mineral fibers include wollastonite and potassium titanate fibers. Among these, artificial mineral fibers are preferred. Among artificial mineral fibers, rock wool is preferred. In one embodiment, the fiber-based flame retardant is an inorganic substance. In one embodiment, the fiber-based flame retardant is not asbestos.

[0022] [1.1.3. Other Ingredients] The second layer may contain components other than those mentioned above. An example of such a component is a curing agent.

[0023] The curing agent is a component that imparts rubber elasticity to the second layer. Those skilled in the art can appropriately select the curing agent according to the reaction mechanism for imparting rubber elasticity. Examples of reaction mechanisms by curing agents include crosslinking reactions, condensation reactions, and addition reactions.

[0024] Organic peroxides can be used to impart rubber elasticity through a crosslinking reaction. Examples of organic peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, cumyl-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butyl peroxyhexane, and di-t-butyl peroxide.

[0025] When rubber elasticity is imparted by a condensation reaction, silicon-containing crosslinking agents and curing catalysts can be used. Examples of silicon-containing crosslinking agents include alkoxysilanes, acetoxysilanes, and cyclic siloxanes. Examples of curing catalysts include metal carboxylate salts and organotin compounds.

[0026] When rubber elasticity is imparted by an addition reaction, organohydrogenpolysiloxanes and platinum-based catalysts can be used. Organohydrogenpolysiloxanes are polyorganosiloxanes in which, on average, two or more hydrogen atoms are bonded to silicon atoms per molecule.

[0027] Silicone rubber compositions may contain oils. Among oils, silicone oils are preferred, and modified silicone oils are more preferred. Silicone oil refers to an oil whose main component is polyorganosiloxane. Modified silicone oil refers to a silicone oil in which some of the methyl groups contained in dimethyl silicone oil are replaced with other functional groups. Examples of modified silicone oils include amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, carbinol-modified silicone oil, (meth)acrylic-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, higher alkoxy-modified silicone oil, fluorine-modified silicone oil, and aralkyl-modified silicone oil. Modified silicone oils include non-reactive modified silicone oils and reactive modified silicone oils. Among these, non-reactive modified silicone oils are preferred.

[0028] The second layer may contain various additives known in the art. Examples of such additives include reinforcing fillers (silica, diatomaceous earth, quartz powder, mica, titanium oxide, etc.); bulking fillers (diatomaceous earth, quartz powder, mica, clay, glass beads, aluminum oxide, etc.); heat resistance improvers (carbon black, red iron oxide, alkali metal oxides, alkaline earth metal oxides, etc.); and pigments.

[0029] [1.1.4. Composition of the second layer] Based on the total weight of the second layer, the lower limit of the content of the second flame-retardant silicone rubber compound is preferably 50% by weight or more, and more preferably 55% by weight or more. The upper limit of the content of the second flame-retardant silicone rubber compound may be, for example, 98% by weight or less.

[0030] Based on the total weight of the second layer, the lower limit of the silicone rubber polymer (polyorganosiloxane) content is preferably 10% by weight or more, more preferably 15% by weight or more, and even more preferably 18% by weight or more. The upper limit of the silicone rubber polymer content may be, for example, 98% by weight or less.

[0031] If the second layer contains rubber components other than silicone rubber, the proportion of silicone rubber in the total rubber components is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 90% by weight or more. In one embodiment, the second layer does not contain rubber components other than silicone rubber. Examples of rubber components other than silicone rubber include fluororubber (FKM), natural rubber (NR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), urethane rubber (U), ethylene-acrylic rubber (AEM), and acrylic rubber (ACM).

[0032] The lower limit of the content of the fibrous flame retardant in the second layer is 5 parts by weight or more, preferably 15 parts by weight or more, more preferably 20 parts by weight or more, even more preferably 25 parts by weight or more, and particularly preferably 30 parts by weight or more, based on the content of the second flame-retardant silicone rubber compound being 100 parts by weight. If the lower limit of the content is within the above range, it tends to provide sufficient flame retardancy to the silicone rubber laminate. The upper limit of the content of the fibrous flame retardant in the second layer is 60 parts by weight or less, preferably 50 parts by weight or less, more preferably 45 parts by weight or less, and even more preferably 40 parts by weight or less, based on the content of the second flame-retardant silicone rubber compound being 100 parts by weight. If the upper limit of the content is within the above range, it tends to maintain the elongation of the silicone rubber laminate after combustion.

[0033] The lower limit of the oil content in the second layer is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and even more preferably 0.5% by weight or more, based on the total weight of the second layer. If the oil content is less than 0.1% by weight, the processability may decrease. The upper limit of the oil content in the second layer is preferably 15% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less, based on the total weight of the second layer. If the oil content exceeds 15% by weight, it may become excessively soft or bleeding may occur.

[0034] The amounts of other components in the second layer can be appropriately determined by those skilled in the art in accordance with common technical knowledge. For example, the content of the curing agent may be 0.2 to 5.0 parts by weight, assuming the content of the second flame-retardant silicone rubber compound is 100 parts by weight.

[0035] [1.2. 1st layer] The first layer contains a first flame-retardant silicone rubber compound. The second layer will be described in the same manner as the first layer.

[0036] [1.2.1. First Flame-Retardant Silicone Rubber Composition] The first flame-retardant silicone rubber compound is a composition in which various additives are blended with silicone rubber to impart flame retardancy. The first flame-retardant silicone rubber compound may be made from the same materials as the second flame-retardant silicone rubber compound, or from different materials.

[0037] In one embodiment, the first flame-retardant silicone rubber compound is HB or higher according to the UL94 standard. That is, the first flame-retardant silicone rubber compound is 5VA, 5VB, V-0, V-1, V-2, or HB according to the UL94 standard. In one embodiment, the first flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. That is, the first flame-retardant silicone rubber compound is 5VA, 5VB, or V-0 according to the UL94 standard. In one embodiment, the first flame-retardant silicone rubber compound is V-0 according to the UL94 standard.

[0038] Examples of commercially available products that fall under the category of the first flame-retardant silicone rubber compound include the following: In addition, XIAMETER (TM) RBB-6630-30, RBB-6640-40, RBB-6650-50, RBB-6660-60, RBB-6670-70, RBB-6680-80, RBB-6671-70 (all from Dow Toray Corporation); SILASTIC (TM) SE 4704 U, SE 4705 U, SE 4706 U, SE 4708 U, DY 32-6014 U, DY 32-7040 U, ​​DY 32-8013 U, SRX 495 U, DY 32-502 U (All of the above are from Dow Toray Industries, Inc.); KE-5634-U, KE-941-U, KE-951-U, KE-961-U, KE-971-U, KE-981-U, KE-971T-U (All of the above are from Shin-Etsu Chemical Co., Ltd.); ELASTOSIL (R) LR 3003 / (x), LR 3004 / (y), LR 3005 / (y), LR 3065 / (e), LR 3092 / 65 Examples include BK (all from Asahi Kasei Wacker Silicone Co., Ltd.); TSE221-3U, TSE221-4U, TSE221-5U, TSE221-6U, TSE221-7U, TSE221-8U, TSE2277U, XE20-523-4U, XE20-523-5U, TSE2181U, TCM5417U, TSE2911U, and TSE2971U (all from Momentive Performance Materials Japan LLC).

[0039] Further explanations regarding the first flame-retardant silicone rubber compound are referenced in Section [1.1.1]. Therefore, a further explanation is omitted in this section.

[0040] [1.2.2. Other Ingredients] The first layer may contain components other than those mentioned above. Examples of such components include curing agents and various additives. The explanations in Section [1.1.3] are referenced for these components; therefore, a further explanation is omitted in this section.

[0041] [1.2.3. Composition of the first layer] Based on the total weight of the first layer, the lower limit of the content of the first flame-retardant silicone rubber compound is preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more. The upper limit of the content of the first flame-retardant silicone rubber compound may be, for example, 99.9% by weight or less.

[0042] Based on the total weight of the first layer, the lower limit of the silicone rubber polymer (polyorganosiloxane) content is preferably 10% by weight or more, more preferably 15% by weight or more, and even more preferably 18% by weight or more. The upper limit of the silicone rubber polymer content may be, for example, 99.9% by weight or less.

[0043] If the first layer contains rubber components other than silicone rubber, the proportion of silicone rubber in the total rubber components is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 90% by weight or more. In one embodiment, the first layer does not contain rubber components other than silicone rubber. Examples of rubber components other than silicone rubber are the rubber components exemplified in Section [1.1.4].

[0044] In one embodiment, the first layer is substantially free of fibrous flame retardant. The content of fibrous flame retardant in the first layer is preferably 1 part by weight or less, more preferably 0.5 parts by weight or less, and even more preferably 0.1 parts by weight or less, based on the content of the first flame-retardant silicone rubber compound being 100 parts by weight. In one embodiment, the first layer is free of fibrous flame retardant. When the content of fibrous flame retardant is within the above range, the silicone rubber laminate comprises a first layer substantially free of fibrous flame retardant and a second layer containing fibrous flame retardant. Silicone rubber laminates with such a structure tend to maintain their elongation even after combustion.

[0045] [1.3. Structure and properties of silicone rubber laminates] A silicone rubber laminate for sealing material according to one aspect of the present invention comprises a first layer and a second layer. In one embodiment, the first layer and the second layer are in contact without an intervening layer (such as an adhesive layer). In another embodiment, the first layer and the second layer are in contact via an intervening layer (such as an adhesive layer). From the viewpoint of flame retardancy, it is preferable that the layers are in contact without an intervening layer. However, a mixed layer formed by mixing a first flame-retardant silicone rubber compound and a second flame-retardant silicone rubber compound may be formed at the interface between the first layer and the second layer. In this specification, the case in which such a mixed layer is formed is also included in the embodiment in which the layers are in contact without an intervening layer. When the first layer and the second layer are in contact via an intervening layer, it is preferable that the intervening layer has excellent flame retardancy.

[0046] In one embodiment, the silicone rubber laminate comprises two or more first and / or second layers. In another embodiment, the silicone rubber laminate comprises one first layer and two second layers. In yet another embodiment, the silicone rubber laminate comprises two first layers and one second layer. These embodiments will be described with reference to Figures 2-4.

[0047] Figure 2 is a schematic diagram showing the general structure of a silicone rubber laminate 10a for sealing material, which comprises a first layer 1 and second layers 2a and 2b. In the silicone rubber laminate 10a for sealing material, the second layers 2a and 2b are provided on both sides of the first layer 1. The compositions of the second layers 2a and 2b may be the same or different.

[0048] Figure 3 is a schematic diagram showing the general structure of a silicone rubber laminate 10b for sealing material, comprising a first layer 1 and a second layer 2. In the silicone rubber laminate 10b for sealing material, the first layer 1 further comprises a first layer 1a and a first layer 1b. The first layer 1a and the first layer 1b have different compositions.

[0049] Figure 4 is a schematic diagram showing the general structure of a silicone rubber laminate 10c for sealing material, comprising a first layer 1 and a second layer 2. In the silicone rubber laminate 10c for sealing material, the second layer 2 further comprises a second layer 2c and a second layer 2d. The second layer 2c and the second layer 2d have different compositions.

[0050] The Shore A hardness of the silicone rubber laminate is preferably 85 or less, and more preferably 80 or less. If the Shore A hardness is within the above range, it can be said that it has a suitable softness for use as a sealing material. In this specification, Shore A hardness is measured using a Type A durometer based on JIS K6253, with the surface of the second layer as the measuring surface. For more specific examples of measurement methods, please refer to the embodiments of this application. Note that the Shore A hardness of the silicone rubber laminate is measured on the cured silicone rubber laminate under normal conditions (without subjecting it to a combustion test).

[0051] The silicone rubber laminate exhibits improved flame retardancy compared to the first flame-retardant silicone rubber compound alone. In this specification, "improved flame retardancy" means that one or more (preferably two or more, more preferably all) of the following three conditions are met. For the method of conducting the flame retardancy test, refer to the examples of this application. • The time of smoke generation is getting later. The time of the flame outbreak is getting later. • The duration of the flame has been shortened.

[0052] ≪2. Sealing materials and batteries≫ A sealing material according to one aspect of the present invention includes the above-described silicone rubber laminate for sealing materials. In this specification, a sealing material is intended to be a molded article used interposed between two or more members. The two or more members may be members whose relative positions change or members that are relatively stationary. The sealing material has the function of sealing the movement of a fluid (gas, liquid, or mixture thereof).

[0053] The applications of the sealing material are not particularly limited. The sealing material according to one embodiment of the present invention has improved flame retardancy and is therefore preferable for use in products where flame retardancy is required. Examples of such products include batteries, vehicles, building materials, home appliances, and mobile devices.

[0054] The following describes an example of using a sealing material according to one embodiment of the present invention in a battery, with reference to Figure 5. The battery 100 comprises a sealing material 10 (silicone rubber laminate for sealing material 10), cells 20, a heat insulating material 30, and a container 40. The battery 100 is configured to extract power from two or more cells 20 (12 cells 20 in Figure 5). Note that in Figure 5, the components for extracting power from the cells 20 are omitted. A specific example of the battery 100 is a non-aqueous electrolyte secondary battery (such as a lithium-ion secondary battery).

[0055] The sealing material 10 is a sealing material according to one aspect of the present invention. The cell 20 is a power generation element in which a positive electrode, negative electrode, separator, electrolyte, etc., are packaged together. The heat insulating material 30 is a component that prevents heat generated by the cell 20 from being transmitted. The container 40 is a component that houses the sealing material 10, the cell 20, and the heat insulating material 30.

[0056] The interior of the container 40 is divided into two or more compartments by the insulation material 30. In Figure 5, it is divided into four compartments: compartment A, compartment B, compartment C, and compartment D. The two or more cells 20 are arranged in two or more of these compartments. In Figure 5, cells 20 are placed in all four compartments A to D, but there may be compartments where cells 20 are not placed. The sealing material 10 is arranged to close the gap between the insulation material 30 and the container 40. At this time, the sealing material 10 is arranged so that the first layer 1 is in contact with the insulation material 30. Since the first layer 1 is relatively softer than the second layer 2, it can follow the positional changes of the insulation material 30, improving the sealing performance. On the other hand, the second layer 2 is arranged to block the space A to D from the first layer 1, so that the first layer 1 does not come into contact with the flame.

[0057] For example, if cell 20 located in section A malfunctions and catches fire, the sealing material 10 and the heat insulating material 30 prevent the fire from spreading to section B. Since the sealing material 10 is a sealing material according to one aspect of the present invention, it has improved flame retardancy compared to conventional sealing materials, and furthermore, it maintains its expansion after combustion. Therefore, the battery 100 is safer than conventional batteries.

[0058] ≪3. Method for manufacturing the first layer, second layer, and silicone rubber laminate≫ The method for producing the first and second layers is not particularly limited. For example, the first layer can be produced by kneading and curing a first composition containing the components described in Section [1.2]. The second layer can be produced by kneading and curing a second composition containing the components described in Section [1.1]. A kneader can be used to knead the components. Examples of kneaders include open rolls, kneaders, planetarium mixers, Banbury mixers, and extruders. The kneading temperature may be 25 to 200°C. The kneading time may be 1 minute to 1 hour. The curing temperature may be 25 to 200°C. The curing time may be 10 seconds to 120 minutes.

[0059] The method for laminating the first and second layers is not particularly limited. In one embodiment, the first and second layers are laminated by insert molding. In another embodiment, the first and second layers are laminated by two-color molding. Specifically, the first and second layers are laminated by injecting the material for the first layer and the material for the second layer using different nozzles, respectively.

[0060] The order of lamination and curing of the first and second layers is not particularly limited. The uncured second layer may be laminated onto the cured first layer, and then the second layer may be cured. The uncured first layer may be laminated onto the cured second layer, and then the first layer may be cured. The cured first layer and the cured second layer may be laminated together. The uncured first layer and the uncured second layer may be laminated together, and then the first and second layers may be cured.

[0061] The cured first layer, second layer, or silicone rubber laminate may be further cured. The curing temperature may be 25 to 250°C. The curing time may be 30 minutes to 4 hours.

[0062] ≪4. Summary≫ The present invention includes the following configuration. <1> A first layer containing a first flame-retardant silicone rubber compound, A second layer containing a second flame-retardant silicone rubber compound and a fiber-based flame retardant, It is equipped with, If the content of the above-mentioned second flame-retardant silicone rubber compound is 100 parts by weight, then the content of the above-mentioned fiber-based flame retardant is 5 to 60 parts by weight. The above-mentioned second flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. Silicone rubber laminate for sealing materials. <2> If the content of the second flame-retardant silicone rubber compound is 100 parts by weight, the content of the fiber-based flame retardant is 25 to 45 parts by weight. <1> The silicone rubber laminate for sealing materials described above. <3> The above-mentioned first flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. <1> or <2> The silicone rubber laminate for sealing materials described above. <4> The above-mentioned fiber-based flame retardant contains one or more selected from the group consisting of artificial mineral fibers and natural mineral fibers. <1> ~ <3> A silicone rubber laminate for sealing materials as described in any of the following. <5> The above-mentioned fiber-based flame retardant contains the above-mentioned artificial mineral fibers, The above artificial mineral fibers include rock wool. <4> The silicone rubber laminate for sealing materials described above. <6> The content of the first flame-retardant silicone rubber compound in the first layer is 50% by weight or more. The content of the second flame-retardant silicone rubber compound in the second layer is 50% by weight or more. <1> ~ <5> A silicone rubber laminate for sealing materials as described in any of the following. <7> The first layer and the second layer are integrally molded by insert molding. <1> ~ <6> A silicone rubber laminate for sealing materials as described in any of the following. <8> The first layer and the second layer described above are molded together as a single unit using two-color molding. <1> ~ <6> A silicone rubber laminate for sealing materials as described in any of the following. <8a> The following conditions (i) or (ii) are met: <1> ~ <8> A silicone rubber laminate for sealing materials as described in any of the following. (i) It comprises one of the first layer and one of the second layer described above. (ii) The first layer and the second layer described above are provided in two or more units. <9> <1> A sealing material comprising a silicone rubber laminate for sealing materials as described in any of <8a>. <10> Two or more cells, insulation material, container, <9> A battery comprising the sealing material described above, The two or more cells mentioned above, the insulating material mentioned above, and the sealing material mentioned above are stored in the container mentioned above. The above-mentioned insulation material is arranged to divide the container into two or more compartments. The two or more cells mentioned above are divided and arranged into two or more sections. The sealing material described above closes the gap between the insulating material and the container, and is positioned so that the first layer is in contact with the insulating material. battery. <11> A first providing step provides a first composition containing a first flame-retardant silicone rubber compound, A second providing step provides a second composition comprising a second flame-retardant silicone rubber compound and a fiber-based flame retardant, A molding step involves molding the above-mentioned first composition and the above-mentioned second composition to obtain a silicone rubber laminate for sealing material having a first layer and a second layer. A method for manufacturing a silicone rubber laminate for sealing materials, including, In the above molding process, The above first layer is obtained by molding the above first composition. The above second layer is obtained by molding the above second composition. In the second composition described above, If the content of the above-mentioned second flame-retardant silicone rubber compound is 100 parts by weight, then the content of the above-mentioned fiber-based flame retardant is 5 to 60 parts by weight. The above-mentioned second flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. A method for manufacturing a silicone rubber laminate for sealing materials. <12> In the above molding process, the first layer and the second layer are integrally molded by insert molding. <11> A method for manufacturing a silicone rubber laminate for sealing materials as described above. <13> In the above molding process, the first layer and the second layer are integrally molded by two-color molding. <11> A method for manufacturing a silicone rubber laminate for sealing materials as described above. [Examples]

[0063] One embodiment of the present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples.

[0064] [Materials used] ● Flame-retardant silicone rubber compound • Flame-retardant silicone rubber compound (KE-5612E-U, Shin-Etsu Chemical Co., Ltd., vinyl methyl silicone rubber compound, UL94 standard: V-0) ● Flame retardant • Fiber-based flame retardants (rock wool, RS490ELS-Roxul1000, Rapinus) • Phosphorus-based flame retardant (Fireguard FCX-210, Teijin Limited) ● Hardener • Hardener (C-3, Shin-Etsu Chemical Co., Ltd., dicumyl peroxide)

[0065] [Examples 1-5, Comparative Examples 5, 6] A vulcanized rubber sheet laminate was fabricated by insert molding according to the following procedure. The vulcanized rubber sheet laminate will be used as the material for preparing test specimens in the tests described later. 1. The components of the second layer listed in Table 1 were kneaded in an open roll. The kneading temperature was 20-100°C. The kneading time was 10-30 minutes. 2. A second layer of unvulcanized rubber sheet was prepared from the resulting mixture. 3. The second layer of unvulcanized rubber sheet was press-vulcanized at 165°C for 10 minutes. In this way, a 1 mm thick vulcanized rubber sheet was obtained. 4. An unvulcanized rubber sheet was prepared from the components of the first layer using the same procedure as in steps 1 and 2. 5. The second layer of vulcanized rubber sheet was placed in a sheet mold with a depth of 2 mm, and the first layer of unvulcanized rubber sheet was placed on top of it. 6. The first layer of unvulcanized rubber sheet was press-vulcanized at 165°C for 10 minutes. 7. Furthermore, secondary vulcanization was performed at 200°C for 4 hours. In this way, a vulcanized rubber sheet laminate with a thickness of 2 mm was obtained.

[0066] [Comparative Examples 1-4] A vulcanized rubber sheet was prepared according to the following procedure. This vulcanized rubber sheet will be used as the material for preparing test specimens in the tests described later. 1. The components of the first or second layer listed in Table 1 were kneaded in an open roll. The kneading temperature was 20-100°C. The kneading time was 10-30 minutes. 2. An unvulcanized rubber sheet was prepared from the resulting mixture. 3. The unvulcanized rubber sheet was press-vulcanized at 165°C for 10 minutes. 4. Furthermore, secondary vulcanization was performed at 200°C for 4 hours. In this way, a vulcanized rubber sheet with a thickness of 2 mm was obtained.

[0067] [Test Method] [1. Hardness under normal conditions] In accordance with JIS K6253, the Shore A hardness of the test specimens was measured before subjecting them to heat resistance or combustion tests. The specific procedure is as follows: 1. A test specimen was prepared by stacking three vulcanized rubber sheets or a laminate of 2 mm thick vulcanized rubber sheets. 2. Measurements were performed using a Type A durometer at 23°C and 50% relative humidity. The peak value of the durometer was defined as the Shore A hardness. When measuring the vulcanized rubber sheet laminate, the surface of the second layer was used as the measurement surface.

[0068] [2. Combustion Test] The test specimens were subjected to combustion tests to evaluate their flame retardancy. The specific procedure is as follows: 1. A sheet measuring 15 mm in width and 100 mm in length was cut from a 2 mm thick vulcanized rubber sheet laminate or vulcanized rubber sheet to serve as a test specimen. 2. The test specimen was fixed to the jig, and the burner flame was adjusted so that the temperature of the combustion area reached 800°C. 3. The test specimen was exposed to a flame for 2 minutes. The time the flame was applied was defined as 0 seconds, and the time (in seconds) when smoke appeared and when the flame appeared were recorded. The duration (in seconds) from when the flame appeared until it was extinguished was also recorded.

[0069] [3. Tensile Test] Dumbbell-shaped test specimens for tensile testing, based on JIS K6251, were cut from samples either before or after the combustion test, and tensile tests were performed. The elongation at break before the combustion test (X1) and the elongation at break after the combustion test (X2) were measured. The rate of change in elongation was also calculated using the following formula. Growth rate (%) = {(X2 - X1) ÷ X1} × 100

[0070] [Table 1] JPEG0007837039000002.jpg247142

[0071] 〔result〕 The test results are shown in Table 1. Comparing Examples 1-5 with Comparative Example 1, it can be seen that the flame retardancy is improved by providing a second layer containing a fiber-based flame retardant. Specifically, the time of smoke generation and flame generation was later in Examples 1-5 than in Comparative Example 1. In addition, the flame duration was shorter in Examples 1-5 than in Comparative Example 1.

[0072] No improvement in flame retardancy was observed when a second layer containing flame retardants other than fiber-based flame retardants was added. In comparative examples 5 and 6, where a second layer containing phosphorus-based flame retardants was added, flame retardancy actually decreased.

[0073] Furthermore, comparing Examples 1-5 with Comparative Examples 2-4, it can be seen that the elongation after combustion is maintained by providing a first layer that does not contain a fiber-based flame retardant. In other words, the degree of decrease in elongation was less in Examples 1-5 than in Comparative Examples 2-4.

[0074] Comparing the examples, the degree of improvement in flame retardancy was greater in Examples 2-5 than in Example 1. Therefore, from the viewpoint of flame retardancy, it is preferable to have a higher content of fibrous flame retardant than in Example 1 (for example, 15 parts by weight or more per 100 parts by weight of flame-retardant silicone rubber compound).

[0075] Furthermore, when comparing the elongation under normal conditions, Examples 1 to 4 showed superior performance. Therefore, from this viewpoint, it is preferable to have a lower content of fibrous flame retardant than in Example 5 (for example, 45 parts by weight or less per 100 parts by weight of flame-retardant silicone rubber compound).

[0076] Furthermore, when comparing the degree to which the elongation after combustion was maintained, Examples 3 to 5 showed superiority. Therefore, from this viewpoint, it is preferable to have a higher content of fibrous flame retardant than in Example 2 (for example, 25 parts by weight or more per 100 parts by weight of flame-retardant silicone rubber compound).

[0077] [Example of anticipated manufacturing] An example of manufacturing a vulcanized rubber sheet laminate by two-color molding is shown below. The vulcanized rubber sheet laminate produced by this manufacturing example is expected to have the same physical properties as the vulcanized rubber sheet laminates described in Examples 1 to 5 and to show similar test results. 1. Mix the ingredients of the second layer using an open roll. The mixing temperature should be 20-100°C. The mixing time should be 10-30 minutes. 2. Mix the ingredients of the first layer in the same manner as in step 1. 3. The kneaded mixture obtained in steps 1 and 2 is filled into separate cylinders of the molding machine. 4. With the mold temperature set to 165°C, the kneaded mixture of the first layer components is injected into a 1mm thick sheet-like cavity. Then, it is held for 5 minutes. 5. Following step 4, the mixture of the second layer components is injected into a 1 mm thick sheet-like cavity. It is then held for 5 minutes. 6. The rubber sheet with the first and second layers laminated was removed from the molding machine and subjected to secondary vulcanization at 200°C for 4 hours. In this way, a vulcanized rubber sheet laminate was obtained. [Industrial applicability]

[0078] The present invention can be used, for example, in sealing materials for batteries and the like. [Explanation of Symbols]

[0079] 1, 1a, 1b: 1st layer 2, 2a, 2b, 2c, 2d: 2nd layer 10, 10a, 10b, 10c: Sealing material (silicone rubber laminate for sealing) 20: Cell 30: Insulation 40: Container 100: Battery

Claims

1. A first layer containing a first flame-retardant silicone rubber compound, A second layer containing a second flame-retardant silicone rubber compound and a fiber-based flame retardant, It is equipped with, If the content of the second flame-retardant silicone rubber compound is 100 parts by weight, then the content of the fiber-based flame retardant is 5 to 60 parts by weight. The above-mentioned second flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. Silicone rubber laminate for sealing materials.

2. The silicone rubber laminate for sealing material according to claim 1, wherein the content of the second flame-retardant silicone rubber compound is 100 parts by weight, and the content of the fibrous flame retardant is 25 to 45 parts by weight.

3. The silicone rubber laminate for sealing material according to claim 1 or 2, wherein the above-mentioned first flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard.

4. The silicone rubber laminate for sealing material according to any one of claims 1 to 3, comprising one or more fibrous flame retardants selected from the group consisting of artificial mineral fibers and natural mineral fibers.

5. The above-mentioned fiber-based flame retardant contains the above-mentioned artificial mineral fibers, The above artificial mineral fibers include rock wool. The silicone rubber laminate for sealing material according to claim 4.

6. The content of the first flame-retardant silicone rubber compound in the first layer is 50% by weight or more. The content of the second flame-retardant silicone rubber compound in the second layer is 50% by weight or more. A silicone rubber laminate for sealing material according to any one of claims 1 to 5.

7. The silicone rubber laminate for sealing material according to any one of claims 1 to 6, wherein the first layer and the second layer are integrally molded by insert molding.

8. The silicone rubber laminate for sealing material according to any one of claims 1 to 6, wherein the first layer and the second layer are integrally molded by two-color molding.

9. A sealing material comprising a silicone rubber laminate for sealing materials according to any one of claims 1 to 8.

10. A battery comprising two or more cells, an insulating material, a container, and the sealing material described in claim 9, The two or more cells mentioned above, the insulating material mentioned above, and the sealing material mentioned above are stored in the container mentioned above. The above-mentioned insulating material is arranged to divide the inside of the container into two or more compartments. The two or more cells mentioned above are divided and arranged into two or more sections. The sealing material described above closes the gap between the insulating material and the container, and is positioned so that the first layer is in contact with the insulating material. battery.

11. A first providing step provides a first composition containing a first flame-retardant silicone rubber compound, A second providing step provides a second composition comprising a second flame-retardant silicone rubber compound and a fiber-based flame retardant, A molding step involves molding the above-mentioned first composition and the above-mentioned second composition to obtain a silicone rubber laminate for sealing material having a first layer and a second layer. A method for manufacturing a silicone rubber laminate for sealing materials, including, In the above molding process, The first layer described above is obtained by molding the first composition described above. The above second layer is obtained by molding the above second composition. In the second composition described above, If the content of the second flame-retardant silicone rubber compound is 100 parts by weight, then the content of the fiber-based flame retardant is 5 to 60 parts by weight. The above-mentioned second flame-retardant silicone rubber compound is V-0 or higher according to the UL94 standard. A method for manufacturing a silicone rubber laminate for sealing materials.

12. The method for manufacturing a silicone rubber laminate for sealing material according to claim 11, wherein in the molding process described above, the first layer and the second layer are integrally molded by insert molding.

13. The method for manufacturing a silicone rubber laminate for sealing material according to claim 11, wherein in the molding process described above, the first layer and the second layer are integrally molded by two-color molding.

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