Method for producing insulating paste and method for storing insulating paste

Abstract

To provide a method for producing an insulating paste with superior production stability during mixing.SOLUTION: The present invention provides a method for producing an insulating paste that comprises an elastomer composition P and a nonaqueous solvent Q. The method includes a mixing step for subjecting a solvent-containing mixture, prepared by adding a nonaqueous solvent Q1 of the same type as the nonaqueous solvent Q to a mixing object comprising at least the elastomer composition P, to a mixing operation using a mixer with stirring blades for planetary motion.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing an insulating paste and a method for storing an insulating paste. [Background technology]

[0002] Various methods for producing insulating pastes have been developed so far. For example, the technique described in Patent Document 1 is known as one such technique. Patent Document 1 describes a method for producing a silicone composition containing an organic solvent, in which fume silica and dibutyltin dilaurate are added to dimethylpolysiloxane, the mixture is kneaded at 150° C. for 2 hours, the kneaded mixture is cooled to room temperature, and then mixed and dissolved in an isooctane-toluene mixed solvent, to which methyltri(methylethylketoxime)silane is added and thoroughly stirred for 2 hours, and γ-aminopropyltriethoxysilane is added and the mixture is filtered through a 100-mesh wire screen to obtain a room-temperature curable silicone composition.

[0003] Furthermore, paragraph 0029 of Patent Document 2 describes a method for producing a conductive liquid silicone composition, which can be obtained by homogeneously dispersing and mixing each component and additional components that are blended as necessary using standard methods; for example, the silicone base polymer of component (A) and the silicone oil of component (B) are charged into a universal mixer or kneader, and then the conductive carbon black of component (C) is added and mixed to homogeneously disperse and mix, and then the solvent of component (E) and the curing agent of component (D) are added to the homogeneous mixture thus obtained, and homogeneously dispersed or dissolved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 52-092267 [Patent Document 2] JP 2010-031292 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, as a result of investigations by the present inventors, it was found that the method for producing an insulating paste described in Patent Document 1 above leaves room for improvement in terms of production stability during kneading. [Means for solving the problem]

[0006] As a result of further investigation, the present inventors have found that by using a mixer with a planetary motion stirring blade in the step of kneading a solvent-containing mixture containing an elastomer composition and a solvent, it is possible to suppress the occurrence of large lumps remaining in the mixture after kneading and improve production stability during kneading, which has led to the completion of the present invention.

[0007] According to one aspect of the present invention, there is provided the following method for producing an insulating paste and method for storing an insulating paste. 1. A method for producing an insulating paste containing an elastomer composition P and a non-aqueous solvent Q, comprising the steps of: A kneading step is included in which a solvent-containing mixture obtained by adding a non-aqueous solvent Q1, which is the same type as the non-aqueous solvent Q, to a material to be kneaded that contains at least an elastomer composition P is kneaded using a mixer with a planetary motion stirring blade. A method for producing an insulating paste. 2. A method for producing the insulating paste according to 1., The method includes a mixing step of preparing a material to be kneaded having a solid content concentration of 100% by mass, The method for producing an insulating paste, further comprising carrying out the kneading step subsequent to the blending step. 3. A method for producing the insulating paste according to 1., a blending step of immersing at least a part of the elastomer composition P in a non-aqueous solvent Q2 of the same kind as the non-aqueous solvent Q to obtain the material to be kneaded, the material including the elastomer composition P and the non-aqueous solvent Q2; The method for producing an insulating paste, further comprising carrying out the kneading step subsequent to the blending step. 4. A method for producing an insulating paste according to any one of 1. to 3., In the kneading step, a solid content concentration adjustment process is further carried out by adding a non-aqueous solvent Q3 of the same kind as the non-aqueous solvent Q to the solvent-containing mixture. 5. A method for producing the insulating paste according to 4., The method for producing an insulating paste, wherein the solid content adjustment treatment is carried out two or more times in the kneading step. 6. A method for producing an insulating paste according to any one of 1. to 5., The method for producing an insulating paste, wherein in the kneading step, the solid content concentration of the solvent-containing mixture after adding the non-aqueous solvent Q1 and immediately before kneading is 90 mass % or less. 7. A method for producing an insulating paste according to any one of 1. to 6., In the kneading step, the elastomer composition P contains a silicone compound, a crosslinking agent, and a catalyst. 8. A method for producing an insulating paste according to any one of 1. to 7., The method for producing an insulating paste further comprises a filtering step of filtering the kneaded mixture obtained in the kneading step. 9. A method for producing an insulating paste according to any one of 1. to 8., The method for producing an insulating paste further comprises a degassing step of subjecting the kneaded mixture obtained in the kneading step to a degassing treatment. 10. A method for producing an insulating paste according to any one of 1. to 9., The method for producing an insulating paste further comprises an evaluation step of determining whether one or more properties selected from the group consisting of viscosity, solid content and gel time of the kneaded product obtained in the kneading step satisfy predetermined conditions. 11. A method for storing an insulating paste, comprising a storage step of storing the insulating paste obtained by the method for producing an insulating paste according to any one of 1. to 10. Effect of the Invention

[0008] According to the present invention, there are provided a method for producing an insulating paste and a method for storing an insulating paste, which are excellent in production stability during kneading. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A method for producing the insulating paste of this embodiment will be described.

[0010] The method for producing an insulating paste of this embodiment produces an insulating paste containing an elastomer composition P and a non-aqueous solvent Q, and includes a kneading step in which a solvent-containing mixture in which a non-aqueous solvent Q1 of the same type as the non-aqueous solvent Q is added to a material to be kneaded that contains at least the elastomer composition P is kneaded using a mixer with a planetary motion stirring blade.

[0011] According to the inventor's findings, it has been found that by using a mixer in which the stirring blades perform planetary motion during kneading (hereinafter sometimes referred to as a "planetary motion blade mixer"), it is possible to impart a more appropriate shear stress to the solvent-containing mixture in which the liquid and solid components are separated and coexist, thereby preventing the formation of large lumps remaining in the mixture after kneading, and to obtain an insulating paste in which the solid and liquid components are integrated and uniformly dispersed. Although the detailed mechanism is unclear, it is presumed that in continuous kneading using a mixer with planetary motion of the stirring blades, new surfaces of the objects to be kneaded, such as compounds, are successively exposed in the solvent-containing mixture, and the surface area to which shear is applied becomes relatively large, so that the entire objects to be kneaded, such as compounds, can be kneaded uniformly.

[0012] In the present embodiment, the object to be kneaded may not have been subjected to an immersion treatment in advance, or may have been subjected to an immersion treatment. When the immersion treatment is not performed, it is possible to shorten the overall production time. On the other hand, when the immersion treatment is performed, although it takes more time for swelling than when the immersion treatment is not performed, the elastomer composition P in the mixture is in a swollen state due to the non-aqueous solvent Q2, which may improve the efficiency of the kneading in the next step.

[0013] An example of the manufacturing method of the first embodiment in which the immersion treatment is not performed may include a preparation step of preparing a material to be kneaded having a solid content concentration of 100 mass %, and the above kneading step may be performed following the preparation step.

[0014] The compounding step may be any step as long as it is a step of obtaining a kneaded material by blending one or more of the components constituting the elastomer composition P. The obtained kneaded material may contain all of the components other than the non-aqueous solvent Q. When two or more kinds of components are used, the order of mixing the multiple components is not particularly limited. In addition, the same kind of components may be mixed at once, or may be mixed in several batches.

[0015] In the kneading step of the first embodiment, a kneading treatment (pre-kneading) may be performed on the material to be kneaded before the non-aqueous solvent Q1 is added, but as in another embodiment described later, it is preferable not to perform a kneading treatment (pre-kneading) on ​​the material to be kneaded before the non-aqueous solvent Q1 is added, but to perform a kneading treatment (main kneading) on ​​the solvent-containing mixture to which the non-aqueous solvent Q1 has been added. The pre-kneading may be performed by the same means as the main kneading.

[0016] If necessary, the materials to be kneaded may be mixed in the preparation step before the kneading step. For the mixing, a known mixing means such as a mixer or a kneader can be used.

[0017] In the first embodiment, the kneading target having a solid content concentration of 100% by mass may be obtained without carrying out a step of adding a non-aqueous solvent Q, and is composed of an elastomer composition P containing at least one component other than the non-aqueous solvent Q. However, a solvent other than the non-aqueous solvent Q contained as a dispersion medium in the components before blending is allowed if it is a small amount (for example, 0.1 mass% or less) relative to the kneading target. In addition, in the manufacturing process of the elastomer composition P, a reaction medium such as water may be added in the manufacturing process for the purpose of promoting the reaction between a filler such as silica particles and a surface treatment agent such as a silane coupling agent. In this case, the manufactured elastomer composition P may contain a small amount of water or a reaction medium, or may not contain water or a reaction medium.

[0018] On the other hand, an example of the manufacturing method of the second embodiment in which an immersion treatment is performed includes a blending step in which an immersion treatment is performed in which at least a part of the elastomer composition P is immersed in the same type of non-aqueous solvent Q2 as the non-aqueous solvent Q, and a kneading target containing the elastomer composition P and the non-aqueous solvent Q2 is obtained, and the above-mentioned kneading step may be performed following the blending step.

[0019] In the second embodiment, the immersion treatment may be carried out until at least a portion of the components (eg, the elastomer components) of the elastomer composition P is in a swollen state in which it appropriately absorbs the non-aqueous solvent Q2. The time for the immersion treatment can be adjusted depending on the type of solvent and the liquid temperature of the non-aqueous solvent Q2, but may be, for example, about 1 to 72 hours. The liquid temperature of the non-aqueous solvent Q2 is not particularly limited, but may be about 0 to 50° C. The type of non-aqueous solvent Q2 will be described in detail later.

[0020] In addition, in the compounding step of the second embodiment, a mixture r1 obtained by immersing at least some of the components of the elastomer composition P in the non-aqueous solvent Q2 and a mixture r2 obtained by immersing at least some of the other components of the elastomer composition P in the non-aqueous solvent Q2 may be at least mixed to obtain a kneaded material.

[0021] During the immersion process, additional mixing steps may be performed, if necessary, either manually or automatically. The mixing steps may be performed once or more than once during the immersion process.

[0022] In another embodiment of the production method, in the kneading step, the upper limit of the solid content concentration of the solvent-containing mixture after the addition of the non-aqueous solvent Q1 and immediately before kneading may be, for example, 90 mass % or less. In the first embodiment, the solid content of the solvent-containing mixture immediately before kneading is preferably 85% by mass or less, more preferably 80% by mass or less, which can reduce the viscosity of the solvent-containing mixture at the beginning of kneading, thereby suppressing poor kneading due to high viscosity caused by the blades of the planetary blade mixer. Poor mixing due to high viscosity may result in the material to be mixed rolling around inside the mixer container without being mixed while the planetary motion blade mixer is in operation, and / or the material to be mixed being twisted and stretched in the height direction of the container. On the other hand, in the second embodiment, the solid content concentration of the solvent-containing mixture immediately before kneading is preferably 80% by mass or less, and more preferably 70% by mass or less. In the kneading step, the lower limit of the solid content concentration of the solvent-containing mixture immediately before kneading may be, for example, 30% by mass or more, preferably 40% by mass or more, and more preferably 45% by mass or more. The viscosity of the solvent-containing mixture at the beginning of kneading is adjusted to be appropriately high, making it easier for the stirring blade to bite into the material to be kneaded, and reducing the kneading efficiency.

[0023] In another embodiment of the production method, in the kneading step, a solids concentration adjustment treatment may be performed in which the solvent-containing mixture is further added with the same type of nonaqueous solvent Q3 as the nonaqueous solvent Q. By adding nonaqueous solvent Q3 after adding nonaqueous solvent Q1, the viscosity of the solvent-containing mixture in the middle of the kneading stage can be lowered, and poor kneading due to high tack caused by the blades of the planetary blade mixer can be suppressed. Poor mixing due to high tack can occur when the material to be mixed rises to the top of the container during operation of a planetary blade mixer and / or when the material to be mixed wraps around the shaft connected to the agitator blade.

[0024] The solid content adjustment treatment may be performed once or twice or more in the kneading step. In other words, the solid content adjustment treatment can suppress an increase in tackiness of the solvent-containing mixture in the middle of the kneading step by adding the same kind of solvent as the non-aqueous solvent Q in multiple portions. The number of times of main kneading in the kneading step is, for example, 2 or more, preferably 3 or more, and more preferably 4 or more. In one preferred embodiment, the kneading step does not include preliminary kneading, and main kneading is performed 3 or more times. This can suppress poor kneading due to high viscosity and poor kneading due to high tack.

[0025] After all of the above solid content adjustment processes are performed, the solid content of the solvent-containing mixture is, for example, 20% by mass to 40% by mass, preferably 25% by mass to 35% by mass, which can suppress an increase in tackiness of the solvent-containing mixture until the end of the kneading process.

[0026] In this embodiment, the non-aqueous solvent Q, the non-aqueous solvent Q1, the non-aqueous solvent Q2, and the non-aqueous solvent Q3 are the same type of solvent. The same type of solvent means a single solvent having the same solvent components, or a mixed solvent having the same main component solvent. Both the single solvent and the mixed solvent allow impurities to be inevitably mixed in. For example, moisture in the air may be mixed in the solvent. In addition, the kneading step may be carried out using a planetary blade mixer in an environment of about room temperature from the initial stage to the final stage.

[0027] The manufacturing method of the present embodiment may also include a filtration step in which a kneaded product obtained in the kneading step is filtered.The manufacturing method of the present embodiment may also include a defoaming step in which a defoaming process is performed on the kneaded product obtained in the kneading step. At least one or both of a filtration step and a defoaming step may be carried out. The order of carrying out these steps is not particularly limited, but the defoaming step may be carried out after the filtration step. Other known treatments may also be carried out.

[0028] The manufacturing method of the present embodiment may also include an evaluation step of determining whether the kneaded product obtained in the kneading step satisfies a predetermined condition in terms of one or more properties selected from the group consisting of viscosity, solid content concentration, and gel time. This improves the manufacturing stability of the insulating paste. The evaluation step may be performed between each of the above steps, or after the last step.

[0029] The method for storing an insulating paste according to the present embodiment includes a step of storing the insulating paste obtained by the method for producing an insulating paste described above. The insulating paste obtained by the method for producing an insulating paste can be stored by a known method.

[0030] The insulating paste can be used as an insulating elastomer material for various applications. The insulating elastomer material can be applied to, for example, wearable devices that can be attached to the body or clothing. Examples of wearable devices include medical sensors that detect phenomena from the living body such as heart rate, electrocardiogram, blood pressure, and body temperature, health care devices, bendable displays, stretchable LED arrays, stretchable solar cells, stretchable antennas, stretchable batteries, actuators, and wearable computers. The molded article can be used as a member for constituting electrodes, wiring, substrates, movable members that stretch or bend, exterior members, and the like used in these devices.

[0031] The elastomer composition P and the non-aqueous solvent Q used in the method for producing the insulating paste will be described in detail below.

[0032] (Elastomer composition P) The elastomer composition P may be silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, etc. Among these, the elastomer is a composition for forming at least one type of elastomer selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. Among these, the elastomer composition P may be a thermosetting elastomer composition or a composition containing a thermoplastic elastomer, is preferably a thermosetting elastomer composition, and is more preferably a silicone rubber composition.

[0033] The silicone rubber composition is preferably a silicone rubber-based hardening composition containing, for example, a silicone compound, a crosslinking agent, and a catalyst. Here, an example of the silicone rubber-based hardening composition will be described. In one example of a silicone rubber-based curable composition, the silicone compound contains a vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) described below, the crosslinking agent contains an organohydrogenpolysiloxane (B), and the catalyst may contain platinum or a platinum compound (E).

[0034] <<Vinyl group-containing organopolysiloxane (A)>> The vinyl group-containing organopolysiloxane (A) can contain a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0035] The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, and these vinyl groups become crosslinking points during curing.

[0036] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it is preferable that the vinyl group content is 15 mol% or less, and more preferably 0.01 to 12 mol%, and that the vinyl group content is two or more in the molecule. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1), and ensures the formation of a network with each component described below. In this embodiment, "to" means that the numerical values ​​at both ends are included.

[0037] In this specification, the vinyl group content refers to the mol % of vinyl group-containing siloxane units when all units constituting the vinyl group-containing linear organopolysiloxane (A1) are taken as 100 mol %, where it is considered that there is one vinyl group per vinyl group-containing siloxane unit.

[0038] The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is, for example, preferably within the range of about 1000 to 10000, and more preferably about 2000 to 5000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number average degree of polymerization (or number average molecular weight) measured by GPC (gel permeation chromatography) using chloroform as a developing solvent.

[0039] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

[0040] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0041] As the vinyl group-containing linear organopolysiloxane (A1), those having a structure represented by the following formula (1) are particularly preferred.

[0042] [ka]

[0043] In formula (1), R 1 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group consisting of a combination thereof, each having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group, with a vinyl group being preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0044] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group consisting of a combination thereof, each having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0045] Also, R 3 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group consisting of a combination thereof. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

[0046] Furthermore, R in formula (1) 1 and R 2 Examples of the substituent of R include a methyl group and a vinyl group. 3 Examples of the substituent include a methyl group.

[0047] In addition, in formula (1), multiple R 1are independent of each other and may be different or the same. 2 , and R 3 The same applies to.

[0048] Furthermore, m and n are the numbers of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer of 0 to 2000 and n is an integer of 1000 to 10000. m is preferably 0 to 1000 and n is preferably 2000 to 5000.

[0049] A specific example of the structure of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) is that represented by the following formula (1-1).

[0050] [ka]

[0051] In formula (1-1), R 1 and R 2 are each independently a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0052] Furthermore, the vinyl group-containing linear organopolysiloxane (A1) preferably contains a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and a vinyl group content of 0.4 mol% or less, and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%. By combining the first vinyl group-containing linear organopolysiloxane (A1-1) having a general vinyl group content as a raw rubber that is a raw material for silicone rubber, and the second vinyl group-containing linear organopolysiloxane (A1-2) having a high vinyl group content, the vinyl groups can be unevenly distributed, and the crosslinking density can be more effectively formed in the crosslinked network of the silicone rubber. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0053] Specifically, the vinyl group-containing linear organopolysiloxane (A1) may be, for example, a vinyl group-containing linear organopolysiloxane represented by the above formula (1-1), 1 is a vinyl group and / or R 2 a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule each of which is a vinyl group and containing 0.4 mol % or less of a unit represented by R 1 is a vinyl group and / or R 2 It is preferable to use a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol % of units in which the vinyl group is present.

[0054] The first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol %, and the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol %.

[0055] Furthermore, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are combined and blended, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1):(A1-2) is preferably 50:50 to 95:5, and more preferably 80:20 to 90:10.

[0056] The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may each be used alone or in combination of two or more.

[0057] The vinyl group-containing organopolysiloxane (A) may also contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0058] <<Organohydrogenpolysiloxane (B)>> The organohydrogenpolysiloxane (B) can contain a linear organohydrogenpolysiloxane (B1) having a linear structure.

[0059] The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the vinyl group-containing organopolysiloxane (A) and with vinyl groups of components blended into the silicone rubber-based curable composition, thereby crosslinking these components.

[0060] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0061] The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by polystyrene conversion in gel permeation chromatography (GPC) using chloroform as a developing solvent.

[0062] Furthermore, it is usually preferred that the linear organohydrogenpolysiloxane (B1) does not have a vinyl group, which can reliably prevent the crosslinking reaction from proceeding within the molecule of the linear organohydrogenpolysiloxane (B1).

[0063] As the linear organohydrogenpolysiloxane (B1) as described above, for example, one having a structure represented by the following formula (2) is preferably used.

[0064] [ka]

[0065] In formula (2), R 4is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these groups, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0066] Also, R 5 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these groups, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0067] In addition, in formula (2), multiple R 4 are independent of each other and may be different or the same. 5 The same applies to R. 4 and R 5 At least two of these are hydride groups.

[0068] Also, R 6 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. 6 are independent of each other and may be different from each other or may be the same.

[0069] In addition, R in formula (2) 4 ,R 5 ,R 6Examples of the substituent include a methyl group and a vinyl group, and from the viewpoint of preventing an intramolecular crosslinking reaction, a methyl group is preferred.

[0070] Furthermore, m and n are the numbers of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

[0071] The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more kinds.

[0072] The organohydrogenpolysiloxane (B) may contain a branched organohydrogenpolysiloxane (B2) having a branched structure.

[0073] <<Silica particles (C)>> The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica, etc. These may be used alone or in combination of two or more kinds.

[0074] The silica particles (C) have a specific surface area, as measured by the BET method, of, for example, 50 to 400 m 2 / g, and 100 to 400m 2 / g is more preferable. The average primary particle size of the silica particles (C) is, for example, preferably from 1 to 100 nm, and more preferably from about 5 to 20 nm.

[0075] By using silica particles (C) having a specific surface area and average particle size within this range, it is possible to improve the hardness and mechanical strength, particularly the tensile strength, of the silicone rubber that is formed.

[0076] <<Silane coupling agent (D)>> The silane coupling agent (D) may have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to become a hydroxyl group, and the hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of the silica particles (C), thereby modifying the surface of the silica particles (C).

[0077] In addition, the silane coupling agent (D) may contain a silane coupling agent having a hydrophobic group. This provides the surface of the silica particles (C) with this hydrophobic group, so that the cohesive force of the silica particles (C) in the silicone rubber-based curable composition and in the silicone rubber is reduced (there is less cohesion due to hydrogen bonds caused by silanol groups), and as a result, it is presumed that the dispersibility of the silica particles in the silicone rubber-based curable composition is improved. This increases the interface between the silica particles and the rubber matrix, and enhances the reinforcing effect of the silica particles. Furthermore, it is presumed that the slipperiness of the silica particles in the matrix is ​​improved during deformation of the rubber matrix. And, due to the improvement in the dispersibility and slipperiness of the silica particles (C), the mechanical strength (for example, tensile strength, tear strength, etc.) of the silicone rubber due to the silica particles (C) is improved.

[0078] Furthermore, the silane coupling agent (D) may contain a silane coupling agent having a vinyl group. This allows the vinyl group to be introduced onto the surface of the silica particles (C). Therefore, when the silicone rubber-based curable composition is cured, that is, when the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure), the vinyl group of the silica particles (C) also participates in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B), so that the silica particles (C) are also incorporated into the network. This allows the formed silicone rubber to have a low hardness and a high modulus.

[0079] As the silane coupling agent (D), a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

[0080] An example of the silane coupling agent (D) is one represented by the following formula (4).

[0081] Y n -Si-(X) 4-n (4) In the above formula (4), n represents an integer of 1 to 3. Y represents any functional group having a hydrophobic group, a hydrophilic group, or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0082] The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group formed by combining these groups, and examples thereof include a methyl group, an ethyl group, a propyl group, and a phenyl group, with a methyl group being particularly preferred.

[0083] In addition, the hydrophilic group may be, for example, a hydroxyl group, a sulfonic acid group, a carboxyl group, or a carbonyl group, and among these, a hydroxyl group is particularly preferred. Note that, although a hydrophilic group may be included as a functional group, it is preferable that the hydrophilic group is not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0084] Further, examples of the hydrolyzable group include alkoxy groups such as methoxy and ethoxy groups, chloro groups, and silazane groups. Among these, silazane groups are preferred because of their high reactivity with the silica particles (C). In addition, those having a silazane group as a hydrolyzable group can be easily obtained by adding (Y n -Si-) structures.

[0085] Specific examples of the silane coupling agent (D) represented by the above formula (4) include, for example, alkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane, which have a hydrophobic group as a functional group. Examples of the silane having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, taking into consideration the above description, it is particularly preferable that the silane having a hydrophobic group is hexamethyldisilazane, and the silane having a vinyl group is divinyltetramethyldisilazane.

[0086] <<Platinum or platinum compounds (E)>> Platinum or a platinum compound (E) is a catalytic component that acts as a catalyst during curing. The amount of platinum or a platinum compound (E) added is a catalytic amount.

[0087] As the platinum or platinum compound (E), known substances can be used, such as platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcohol solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, and a complex salt of chloroplatinic acid and a vinylsiloxane. The platinum or platinum compound (E) may be used alone or in combination of two or more kinds.

[0088] Also, instead of or in combination with platinum or the platinum compound (E), a catalyst other than component (E) may be used. Examples of catalysts other than component (E) include organic peroxides such as ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, peroxyesters, and peroxydicarbonates.

[0089] <<Other ingredients>> Furthermore, the silicone rubber-based hardening composition of the present embodiment may further contain other components in addition to the above components (A) to (F). Examples of these other components include additives such as inorganic fillers other than the silica particles (C), reaction inhibitors, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, and thermal conductivity improvers. These may be used alone or in combination of two or more. Examples of inorganic fillers other than the silica particles (C) include diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, and mica.

[0090] Here, an example of a method for producing a silicone rubber-based hardenable composition will be described.

[0091] First, the components of the silicone rubber-based hardening composition are mixed uniformly using any kneading device to prepare the silicone rubber-based hardening composition.

[0092] [1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed out, and then kneaded using any kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0093] It is preferable to prepare this mixture by first kneading the vinyl-containing organopolysiloxane (A) with the silane coupling agent (D) and then kneading (mixing) the silica particles (C), which improves the dispersibility of the silica particles (C) in the vinyl-containing organopolysiloxane (A).

[0094] In addition, when obtaining this kneaded product, water (F) may be added to the kneaded product of the components (A), (C), and (D) as necessary, which allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0095] Furthermore, when water (F) is contained, its content can be appropriately set, but specifically, for example, it is preferably in the range of 10 to 100 parts by weight, more preferably in the range of 30 to 70 parts by weight, relative to 100 parts by weight of the silane coupling agent (D). This makes it possible to more reliably proceed with the reaction between the silane coupling agent (D) and the silica particles (C).

[0096] Furthermore, it is preferable that the kneading of each of the components (A), (C), and (D) is carried out through a first step of heating at a first temperature and a second step of heating at a second temperature. This allows the surface of the silica particles (C) to be surface-treated with the coupling agent (D) in the first step, and allows the by-products generated by the reaction between the silica particles (C) and the coupling agent (D) to be reliably removed from the kneaded product in the second step. After that, the component (A) may be added to the obtained kneaded product as necessary, and further kneaded. This allows the compatibility of the components in the kneaded product to be improved.

[0097] The first temperature is preferably, for example, about 40 to 120° C., and more preferably, for example, about 60 to 90° C. The second temperature is preferably, for example, about 130 to 210° C., and more preferably, for example, about 160 to 180° C.

[0098] Moreover, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced pressure atmosphere.

[0099] Furthermore, the time for the first step is, for example, preferably about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours, and the time for the second step is, for example, preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

[0100] By setting the above conditions for the first and second steps, the above effects can be obtained more significantly.

[0101] [2] Next, predetermined amounts of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed out, and then, using any kneading device, the components (B) and (E) are kneaded into the mixture prepared in the above step [1] to obtain a silicone rubber-based curable composition (elastomer composition).

[0102] In addition, when mixing the components (B) and (E), it is preferable to mix the mixture prepared in the above step [1] with the organohydrogenpolysiloxane (B) and the mixture prepared in the above step [1] with platinum or a platinum compound (E), and then mix the mixtures together. This allows the components (A) to (E) to be reliably dispersed in the silicone rubber-based curable composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

[0103] The temperature at which the components (B) and (E) are kneaded is, for example, preferably about 10 to 70°C, and more preferably about 25 to 30°C, as roll setting temperature.

[0104] Furthermore, the kneading time is, for example, preferably about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes.

[0105] In the above steps [1] and [2], by setting the temperature within the above range, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more reliably prevented or inhibited. In addition, in the above steps [1] and [2], by setting the kneading time within the above range, the components (A) to (E) can be more reliably dispersed in the silicone rubber-based curable composition.

[0106] The kneading device used in each of steps [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mill, a Banbury mixer (continuous kneader), a pressure kneader, etc. can be used.

[0107] In addition, a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture in step [2], which makes it possible to more effectively prevent or inhibit the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) even if the temperature of the kneaded mixture is set to a relatively high temperature. By the above step [2], a silicone rubber-based curable composition is obtained as an elastomer composition.

[0108] (Non-aqueous solvent Q) The non-aqueous solvent Q may be any of various known solvents, including, for example, high-boiling point solvents, which may be used alone or in combination of two or more.

[0109] The lower limit of the boiling point of the high boiling point solvent is, for example, 100°C or more, preferably 130°C or more, and more preferably 150°C or more. This can improve the film formability of the coating film obtained when applying the insulating paste on the support substrate and suppress the film thickness variation of the coating film. On the other hand, the upper limit of the boiling point of the high boiling point solvent is not particularly limited, but may be, for example, 300°C or less, 290°C or less, or 280°C or less. This can suppress excessive heat history during wiring formation, so that damage to electronic components and wiring can be suppressed. In addition, since the solvent in the elastomer of the insulating paste has been sufficiently volatilized, it is possible to use the insulating paste as a substrate, and the shape of the wiring formed by printing using the conductive paste on the surface of the substrate can be well maintained.

[0110] The non-aqueous solvent Q can be appropriately selected from the viewpoints of the solubility and boiling point of the elastomer, and may include, for example, aliphatic hydrocarbons having 5 to 20 carbon atoms, preferably aliphatic hydrocarbons having 8 to 18 carbon atoms, and more preferably aliphatic hydrocarbons having 10 to 15 carbon atoms.

[0111] Examples of the non-aqueous solvent Q include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, trifluoromethylbenzene, and benzotrifluoride; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; and sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide. These may be used alone or in combination of two or more. The non-aqueous solvent Q used here may be appropriately selected from among solvents capable of uniformly dissolving or dispersing the above components.

[0112] In addition, the non-aqueous solvent Q has a polarity term (δ p ) is, for example, 10MPa 1 / 2 or less, preferably 7 MPa 1 / 2 More preferably, it is 5.5 MPa or less. 1 / 2 The insulating paste may contain a first solvent having the polarity (δ) of 0.1 to 1.0, which is the same as that of the silicone rubber-based curable resin composition. This makes it possible to improve the dispersibility and solubility of the elastomer composition, such as the silicone rubber-based curable resin composition, in the insulating paste. p The lower limit of the pressure is not particularly limited, but may be, for example, 0 Pa. 1 / 2 More than that is fine.

[0113] The hydrogen bond term of the Hansen solubility parameters in the first solvent (δ h) is, for example, 20MPa 1 / 2 or less, preferably 10 MPa 1 / 2 More preferably, it is 7 MPa or less. 1 / 2 This makes it possible to improve the dispersibility and solubility of the elastomer composition, such as the silicone rubber-based curable resin composition, in the insulating paste. h The lower limit of the pressure is not particularly limited, but may be, for example, 0 Pa. 1 / 2 More than that is fine.

[0114] Hansen solubility parameters (HSP) are an index that indicates the degree to which a substance dissolves in another substance. HSP expresses solubility as a three-dimensional vector. This three-dimensional vector is typically expressed by the dispersion term (δ d ), polarity term (δ p ), hydrogen bond term (δ h ) and it can be determined that compounds with similar vectors have high solubility. The similarity of vectors can be determined by the Hansen Solubility Parameter distance (HSP distance).

[0115] As used herein, the Hansen Solubility Parameters (HSP values) can be calculated using software called HSPiP (Hansen Solubility Parameters in Practice), where the computer software HSPiP developed by Hansen and Abbott includes a function for calculating HSP distances and a database of Hansen parameters for various resins and solvents or non-solvents. The solubility of each resin in pure solvents and mixed solvents of good and poor solvents is investigated, and the results are entered into the HSPiP software to calculate D: dispersion term, P: polarity term, H: hydrogen bond term, and R0: radius of the solubility sphere.

[0116] As the non-aqueous solvent Q, for example, one having a small difference in HSP distance, polarity term, or hydrogen bond term between the elastomer or the structural units constituting the elastomer and the solvent can be selected.

[0117] An example of the insulating paste obtained by the manufacturing method of this embodiment will be described.

[0118] The lower limit of the content of the elastomer composition P in the insulating paste is, for example, preferably 5 mass% or more, more preferably 8 mass% or more, and even more preferably 10 mass% or more, based on 100% mass of the insulating paste. On the other hand, the upper limit of the content of the elastomer composition P in the insulating paste is, for example, preferably 50 mass% or less, more preferably 45 mass% or less, and even more preferably 40 mass% or less, based on 100% insulating paste mass. By making the content of the elastomer composition P equal to or greater than the lower limit, the elastomer of the insulating paste can have appropriate flexibility, while by making the content of the elastomer composition equal to or less than the upper limit, the mechanical strength of the elastomer can be improved.

[0119] The insulating paste may contain a non-conductive filler such as silica particles (C) as necessary. This can improve the hardness and mechanical strength of the elastomer formed from the insulating paste. Also, the insulating properties of the elastomer in the insulating paste can be improved.

[0120] The lower limit of the content of the silica particles (C) in the insulating paste is, for example, preferably 1 mass % or more, more preferably 3 mass % or more, and even more preferably 5 mass % or more, based on 100% mass of the insulating paste. On the other hand, the upper limit of the content of the silica particles (C) in the insulating paste is, for example, preferably 50 mass % or less, more preferably 45 mass % or less, and even more preferably 40 mass % or less, based on 100% mass of the insulating paste. By setting the content of the silica particles (C) or the non-conductive filler to the above lower limit or more, the elastomer of the insulating paste can have an appropriate mechanical strength. On the other hand, by setting the content of the silica particles (C) or the non-conductive filler to the above upper limit or less, the elastomer can have an appropriate stretching property. This can increase the durability during repeated use.

[0121] The lower limit of the content of the silane coupling agent (D) in the insulating paste is, for example, preferably 1 mass % or more, more preferably 3 mass % or more, and even more preferably 5 mass % or more, relative to 100 weight % of the total amount of the vinyl group-containing organopolysiloxane (A). On the other hand, the upper limit of the content of the silane coupling agent (D) is, for example, preferably 100 mass% or less, more preferably 80 mass% or less, and even more preferably 40 mass% or less, relative to 100 weight% of the total amount of the vinyl group-containing organopolysiloxane (A). By making the content of the silane coupling agent (D) equal to or greater than the lower limit, the elastomer of the insulating paste has appropriate adhesion to the substrate, and when silica particles (C) are used, this contributes to improving the mechanical strength of the elastomer as a whole. Also, by making the content of the silane coupling agent (D) equal to or less than the upper limit, the elastomer can have appropriate mechanical properties.

[0122] The lower limit of the content of platinum or platinum compound (E) in the insulating paste is, for example, preferably 0.0001 mass% or more, more preferably 0.0002 mass% or more, and even more preferably 0.0003 mass% or more, based on 100% mass of the insulating paste. On the other hand, the upper limit of the content of platinum or platinum compound (E) in the insulating paste is, for example, preferably 1 mass% or less, more preferably 0.5 mass% or less, and even more preferably 0.1 mass% or less, based on 100% mass of the insulating paste. By making the content of platinum or platinum compound (E) equal to or greater than the above lower limit, the insulating paste can be cured at an appropriate speed. Also, by making the content of platinum or platinum compound (E) equal to or less than the above upper limit, the cost of producing the insulating paste can be reduced.

[0123] The lower limit of the viscosity of the insulating paste when measured at a shear rate of 20 [1 / s] at room temperature of 25°C is, for example, 1 Pa·s or more, preferably 5 Pa·s or more, and more preferably 10 Pa·s or more. This can improve film formability. Also, even when forming a thick film, it is possible to suppress film thickness variations. On the other hand, the upper limit of the viscosity of the insulating paste at room temperature of 25°C is, for example, 100 Pa·s or less, preferably 90 Pa·s or less, and more preferably 80 Pa·s or less. This can improve the ease of application and printability of the insulating paste.

[0124] In the insulating paste of this embodiment, the viscosity measured at room temperature 25° C. and a shear rate of 1 [1 / s] is η1, the viscosity measured at a shear rate of 5 [1 / s] is η5, and the thixotropic index is the viscosity ratio (η1 / η5). At this time, the lower limit of the thixotropic index is, for example, 1.0 or more, preferably 1.1 or more, and more preferably 1.2 or more. This makes it easy to print the insulating paste using a squeegee or the like. On the other hand, the upper limit of the thixotropic index is, for example, 3.0 or less, preferably 2.5 or less, and more preferably 2.0 or less. This can improve the leveling property of the insulating paste.

[0125] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. EXAMPLES

[0126] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0127] <Elastomer composition P> The vinyl group-containing organopolysiloxane (A), the silane coupling agent (D) and the water (F) were mixed in a predetermined ratio, and a predetermined amount of silica particles (C) was added and further mixed to obtain a silicone rubber compound. To the silicone rubber compound, a predetermined amount of organohydrogenpolysiloxane (B) as a crosslinking agent, platinum or a platinum compound (E) as a catalyst, and a reaction inhibitor were added and mixed to obtain an elastomer composition P (a silicone rubber-based curable composition).

[0128] <Production of insulating paste> [Example 1] The obtained elastomer composition P was used as a material to be kneaded having a solid content concentration of 100 mass % (mixing step). First, the material to be kneaded was preliminarily kneaded using a planetary mixer, which is a mixer in which the stirring blade moves in planetary motion. Next, decane was added as the non-aqueous solvent Q1 to the pre-mixed material to adjust the solid content to 80 mass %, and the solvent-containing mixture was then subjected to a first main mixing using a planetary mixer. Thereafter, decane was added as the non-aqueous solvent Q3 to the solvent-containing mixture after the first main kneading, and a second main kneading was carried out using a planetary mixer (kneading step). Through the above-mentioned mixing and kneading steps (main kneading: a total of two times), an insulating paste with a solid content of 30 mass % was produced.

[0129] [Example 2] Preliminary kneading and the first main kneading were carried out in the same manner as in Example 1, and then main kneading was carried out two additional times by adding decane as the non-aqueous solvent Q3 and kneading using a planetary mixer (kneading step). Through the above-mentioned mixing and kneading steps (main kneading: a total of three times), an insulating paste with a solid content of 30 mass % was produced.

[0130] The obtained elastomer composition P was used as a material to be kneaded having a solid content concentration of 100 mass % (mixing step). First, without carrying out preliminary kneading on this material to be kneaded, decane was added as the non-aqueous solvent Q1 to adjust the solid content concentration to 80 mass %, and then the solvent-containing mixture was subjected to a first main kneading using a planetary mixer. Thereafter, decane was added as the non-aqueous solvent Q3 to the solvent-containing mixture after the first main kneading, and the main kneading was carried out four additional times using a planetary mixer (kneading step). Through the above-mentioned mixing and kneading steps (main kneading: a total of 5 times), an insulating paste with a solid content of 30 mass % was produced.

[0131] [Comparative Example 1] The obtained elastomer composition P was used as a material to be kneaded having a solid content concentration of 100 mass % (mixing step). Decane was added to this material to be kneaded as the non-aqueous solvent Q2, and the solid content was adjusted to 65% by mass. The material was then immersed in a room temperature environment for 24 hours or more (immersion step). Decane was added as the non-aqueous solvent Q1 to the solvent-containing mixture after immersion, and kneading was carried out by hand to obtain a uniform mixture (kneading step). Through the above-mentioned mixing step, immersion step, and kneading step (hand mixing), an insulating paste with a solid content concentration of 30 mass % was produced.

[0132] <Evaluation of manufacturing efficiency> When the combined time of the immersion step and the kneading step in Comparative Example 1 was taken as 100, the kneading times (relative values) in the kneading steps in Examples 1 to 3 were measured and the evaluation results based on the following criteria are shown in Table 1. When the kneading time (relative value) was 30 or less, the kneading process was extremely shortened and the manufacturing efficiency was evaluated as excellent; when it was between 30 and 60, the kneading process was relatively shortened and the manufacturing efficiency was evaluated as good; when it was over 60, the kneading process was hardly shortened and the manufacturing efficiency was evaluated as poor.

[0133] <Evaluation of manufacturing stability> (Large chunks remaining) In Examples 1 to 3 and Comparative Example 1, the presence or absence of hard lumps having a diameter of about 2 to 3 cm in the insulating paste immediately after the kneading step was confirmed.

[0134] <Evaluation of kneadability> (Mixability 1) In Examples 1 to 3 using a planetary mixer, it was confirmed whether or not the phenomenon occurred in which the material to be kneaded rolls in the container of the mixer without being kneaded during the kneading process, and / or the material to be kneaded is twisted and stretched in the height direction of the container. As a result, this phenomenon was not confirmed in Examples 2 and 3, so it was determined that kneadability 1 was better than Example 1.

[0135] (Mixability 2) In Examples 1 to 3 using a planetary mixer, it was confirmed whether or not the phenomenon of the material to be kneaded rising to the top of the container and / or wrapping around the shaft portion connected to the stirring blade occurs during the kneading process. As a result, this phenomenon was not confirmed in Example 3, so it was determined that the kneadability 2 was better than Examples 1 and 2.

[0136] [Table 1]

[0137] The methods for producing the insulating pastes of Examples 1 to 3 showed results that the production time could be shortened and that the production stability during kneading was excellent, as compared with the comparative example.

Claims

1. A method for producing an insulating paste containing an elastomer composition P and a non-aqueous solvent Q, comprising the steps of: A kneading step is included in which a solvent-containing mixture obtained by adding a non-aqueous solvent Q1, which is the same type as the non-aqueous solvent Q, to a material to be kneaded that contains at least an elastomer composition P is kneaded using a mixer having a planetary motion stirring blade. A method for producing an insulating paste.

2. A method for producing an insulating paste according to claim 1, comprising the steps of: A mixing step of preparing the material to be kneaded having a solid content concentration of 100% by mass is included, The method for producing an insulating paste, further comprising carrying out the kneading step subsequent to the blending step.

3. A method for producing an insulating paste according to claim 1, comprising the steps of: a blending step of immersing at least a part of the elastomer composition P in the same non-aqueous solvent Q2 as the non-aqueous solvent Q to obtain the material to be kneaded, the material including the elastomer composition P and the non-aqueous solvent Q2; The method for producing an insulating paste, further comprising carrying out the kneading step subsequent to the blending step.

4. A method for producing an insulating paste according to claim 1 or 2, In the kneading step, a solid content concentration adjustment process is further carried out by adding a non-aqueous solvent Q3 of the same kind as the non-aqueous solvent Q to the solvent-containing mixture.

5. A method for producing an insulating paste according to claim 4, comprising the steps of: The method for producing an insulating paste, wherein the solid content adjustment treatment is carried out two or more times in the kneading step.

6. A method for producing an insulating paste according to claim 1 or 2, In the kneading step, the solid content concentration of the solvent-containing mixture after the addition of the non-aqueous solvent Q1 and immediately before kneading is 90 mass % or less.

7. A method for producing an insulating paste according to claim 1 or 2, In the kneading step, the elastomer composition P contains a silicone compound, a crosslinking agent, and a catalyst.

8. A method for producing an insulating paste according to claim 1 or 2, The method for producing an insulating paste further comprises a filtering step of filtering the kneaded mixture obtained in the kneading step.

9. A method for producing an insulating paste according to claim 1 or 2, The method for producing an insulating paste further comprises a degassing step of subjecting the kneaded mixture obtained in the kneading step to a degassing treatment.

10. A method for producing an insulating paste according to claim 1 or 2, The method for producing an insulating paste further comprises an evaluation step of determining whether one or more properties selected from the group consisting of viscosity, solid content and gel time of the kneaded product obtained in the kneading step satisfy predetermined conditions.

11. A method for storing an insulating paste, comprising a storage step of storing the insulating paste obtained by the method for producing an insulating paste according to claim 1 or 2.

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