Heat-insulating silicone composition and production method of heat-insulating cured product using the composition

Abstract

To provide a heat-insulating silicone composition which has low adhesiveness at high temperature and which can improve flexibility.SOLUTION: A heat-insulating silicone composition comprises (A) an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in a molecule, (B) an organohydrogenpolysiloxane containing 0.0001 mol / g or more and 0.005 mol / g or less of hydrogen atoms bonded to silicon atoms, (C) a hollow filler formed of an organic resin, and (D) an addition reaction catalyst. When a total amount of the component (A) and the component (B) is set to be 100 pts.mass, the content of the component (C) is 5 pts.mass or more and 25 pts.mass or less, the content of the component (D) is 0.05 pts.mass or more and 1.8 pts.mass or less, and a molar ratio [Si-H group / alkenyl group] of a total amount of Si-H group contained in the total amount of the heat-insulating silicone composition to a total amount of the alkenyl group bonded to silicon atoms in the component (A) is 0.5 or more and 1.0 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a heat insulating silicone composition and a method for producing a heat insulating cured product using the composition. [Background technology]

[0002] Silicone rubber adhesive compositions are used as protective agents for adhesion and fixation, heat resistance, weather resistance, electrical insulation, etc. in a variety of electrical and electronic parts, automotive parts, and various computer-related parts such as PCs and mobile terminals.

[0003] Patent Document 1 discloses a low-specific-gravity silicone rubber adhesive composition that has cushioning and heat insulating properties despite its low specific gravity, achieved by adding an adhesive aid to a silicone rubber composition containing organic resin hollow fillers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5115716 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in high-temperature environments, components such as battery housings may expand. The cured product of the silicone rubber adhesive composition of Patent Document 1 has high adhesiveness, and if it is placed around an expanding component, it may compress the expanding force and destroy the component.

[0006] The present disclosure provides a heat insulating silicone composition that exhibits low adhesion and improved flexibility at high temperatures, and a method for producing a heat insulating cured product using the same. [Means for solving the problem]

[0007] The heat insulating silicone composition of the present disclosure comprises: (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule; (B) an organohydrogenpolysiloxane containing 0.0001 mol / g or more and 0.005 mol / g or less of hydrogen atoms bonded to silicon atoms; (C) an organic resin hollow filler; (D) an addition reaction catalyst; Includes.

[0008] When the total amount of the component (A) and the component (B) is 100 parts by mass, The content of the component (C) is 5 parts by mass or more and 25 parts by mass or less, The content of the component (D) is 0.05 parts by mass or more and 1.8 parts by mass or less, The molar ratio of the total alkenyl groups bonded to silicon atoms in component (A) to the total Si-H groups contained in the entire heat insulating silicone composition [Si-H groups / alkenyl groups] may be 0.5 or greater and 1.0 or less. The molar ratio [Si—H group / alkenyl group] may preferably be 0.5 or more and 0.9 or less.

[0009] The component (C) may have an inorganic substance attached to at least a portion of its surface. The inorganic substance of the component (C) may be subjected to an affinity surface treatment or a dispersibility surface treatment. The true density of the component (C) is 0.2 g / cm 3 The following is also acceptable. The average particle size of the component (C) may be 150 μm or less, and more preferably from 30 to 80 μm.

[0010] The heat insulating silicone composition comprises: (E) A silicone resin having a number average molecular weight of 1,000 or more and 10,000 or less, preferably 1,400 or more and 4,000 or less, more preferably 1,400 or more and 2,500 or less, and having at least one alkenyl group in the molecule, may be further included.

[0011] The heat insulating silicone composition preferably does not contain silica.

[0012] The heat insulating silicone composition preferably does not contain an adhesion promoter.

[0013] The viscosity of the uncured heat insulating silicone composition at 25°C may be 10,000 mPa·s or less, more preferably 1,000 mPa·s or more and 4,000 mPa·s or less. When the heat insulating silicone composition is a two-part mixture, the viscosity of each of the first and second parts at 25°C may be 10,000 mPa·s or less, more preferably 1,000 mPa·s or more and 4,000 mPa·s or less. After mixing the first and second parts, the viscosity at 25°C before the start of curing or at the early stage of curing may be 10,000 mPa·s or less, more preferably 1,000 mPa·s or more and 4,000 mPa·s or less. (Measurement method) The viscosity of the heat insulating silicone composition at 25°C is measured in accordance with JIS K 7117-2. For example, the uncured heat insulating silicone composition is placed between a fixed plate and a 25 mm diameter cone rotating at an angle of 1° or 2°, and the viscosity is measured using a viscometer at a shear rate of 10 (1 / s) and a gap of 0.106 mm.

[0014] The thermal conductivity of the heat-insulating cured product obtained by curing the heat-insulating silicone composition may be 0.2 W / mK or less, preferably 0.1 W / mK or more and 0.18 W / mK or less, and more preferably 0.12 W / mK or more and 0.15 W / mK or less. (Measurement method) The thermal conductivity of the heat-insulating cured product is measured at 25°C in accordance with ISO 22007-2. For example, the thermal conductivity is measured by sandwiching a sensor between two test pieces of heat-insulating silicone composition, each 40 mm in diameter and 10 mm in height, that have been cured at 100°C for 30 minutes.

[0015] The heat insulating cured product obtained by curing the heat insulating silicone composition may have a hardness (penetration) of 10 or more and 40 or less. (Measurement method) The penetration of a cured heat-insulating material at 23°C is measured in accordance with ASTM D 2240. For example, the penetration of a cured heat-insulating material obtained by curing a heat-insulating silicone composition in a 60 mL container at 100°C for 30 minutes is measured. "Penetration" is expressed as the length of penetration of a standard steel needle into a sample at a constant temperature. A 100 g load is applied, and the penetration length is measured over a 5-second period. The measured penetration depth of the needle is expressed in 1 / 10 mm units.

[0016] The specific gravity of the heat insulating cured product obtained by curing the heat insulating silicone composition may be 0.7 or less.

[0017] The density of the heat insulating cured product obtained by curing the heat insulating silicone composition may be 0.5 g / cc or more and 0.68 g / cc or less, and preferably 0.52 g / cc or more and 0.67 g / cc or less. (Measurement method) The density of the heat insulating cured product is measured at 23°C in accordance with JIS K 6249. For example, the density of a test piece of the heat insulating silicone composition cured at 100°C for 30 minutes is measured by the immersion method.

[0018] The heat insulating cured product obtained by curing the heat insulating silicone composition may have a tensile strength of 50 kPa or more and 400 kPa or less. (Measurement method) The tensile strength of the heat insulating cured product is measured at 25°C according to JIS K 6251. For example, a 2 mm thick sheet of the heat insulating silicone composition cured at 100°C for 30 minutes is punched out into a No. 3 dumbbell shape, and the breaking strength and elongation are measured using a tensile tester when pulled at a pulling rate of 500 mm / min.

[0019] The heat insulating silicone composition comprises: The floatability of the component (C) relative to other components may be 40% or more and 70% or less, preferably 40% or more and 65% or less. (Measurement method) The ease of filler floating is determined from the interface position between the liquid phase (silicone phase) and the filler phase (component C phase) after allowing the uncured heat-insulating silicone composition to stand for a certain period of time. For example, the material (part 1 or part 2) is poured into a 50 mL container with a diameter of 35 mm and a height of 78 mm to a filling height of 55 mm from the bottom, and after storing it at high temperature for a specified time (for example, 1 week at 50°C), the interface position between the silicone phase and the filler phase is measured with a ruler or the like, and the ease of filler floating is determined from the interface position and the amount of filler filled. The volume fraction of the blended amounts of component C and other components in the heat insulating silicone composition is determined. For example, component C: liquid phase of other components = 4:6 Theoretical liquid height H0 = liquid volume fraction (6 / 10) x 55 mm (filling height) After storing at high temperature for a specified time, the height H1 of the liquid phase is measured with a ruler. For example, when the measured interface position H1 is 16.5 mm (the ratio of the height of the liquid phase of component C to the other components is 7:3), Floatability = H1 / H0 x 100 = 16.5 / 33 x 100 = 50%

[0020] The strength of the component (C) may be 2N or less. (Measurement method) After evaluating the ease of floating, the strength of the filler (component C) floating on the surface of the sample is measured. For example, the maximum load value when a spherical compression tool with a diameter of φ12.7 mm is pressed against the sample at a compression speed of 240 mm / min is measured using a compression tester.

[0021] The heat insulating cured product obtained by curing the heat insulating silicone composition may have a volumetric shrinkage of 15% to 34% after heating compared to before heating (volume change rate of -34% to -15%) when heated at 190°C to 210°C for 1 to 2.5 hours. (Measurement method) The volume change rate of a sample heated for a predetermined time (e.g., 2 hours) in a heating device (e.g., an oven) at a predetermined temperature (e.g., 200°C) is measured. For example, the heat insulating silicone composition is cured at 100°C for 30 minutes, and a test piece with a diameter of 40 mm and a height of 10 mm is measured for weight and density, and the volume (before heat shrinkage) is calculated. The weight and density of the test piece heated in an oven at 200°C for 2 hours and then cooled to room temperature are measured, and the volume (after heat shrinkage) is calculated. The volume change rate is calculated from the difference in volume before and after heating. Volume change rate = (volume after heat shrinkage - volume before heat shrinkage) / volume before heat shrinkage × 100 [%]

[0022] A method for producing a heat-insulating cured product obtained by curing the heat-insulating silicone composition, comprising the steps of: a step of potting (filling or applying) the heat insulating silicone composition onto a substrate; The method includes a step of curing the potted layer of the heat insulating silicone composition at a temperature of 5°C or higher and 100°C or lower, more preferably 15°C or higher and 50°C or lower.

[0023] (Action and effect) (1) The Si-H groups interact with functional groups (such as -OH groups) on the surface of the adherend to provide adhesion, but the amount of organohydrogenpolysiloxane in this composition (i.e., the density of SiH groups) is low, so the adhesion is lower than that of Patent Document 1. (2) The composition cures by crosslinking through an addition reaction between Si-H groups and Si-alkenyl groups. However, since the amount of Si-H in this composition is low, the crosslink density is low, and the hardness of the cured product obtained after curing is low and it is soft. (3) Compared with the composition of Patent Document 1, the heat insulating silicone composition has low adhesiveness and improved flexibility, and furthermore, the cured product shrinks above a certain temperature. (4) By blending a silicone resin, the brittleness of the heat-insulating cured product obtained by curing the heat-insulating silicone composition can be reduced. (5) By not incorporating silica, the viscosity of the heat insulating silicone composition can be reduced. (6) By reducing the viscosity, workability, operability, and potting properties can be improved. (7) This composition functions as a potting agent, and it is sufficient if it has a certain degree of hardness and adhesiveness. The cured product of this composition can be cleanly peeled off above a certain temperature, making it easy to rework and maintain. (8) Conventional electric vehicle battery cells are covered with a highly adhesive insulating material to prevent the spread of fire in the event of damage or explosion. However, this strong adhesion makes recycling difficult and increases the environmental burden. This invention provides an insulating material with controlled adhesive strength to the battery cell skin to improve recyclability. Weakening the adhesive strength makes disassembly easier and improves resource recovery rates. This invention contributes to reducing the environmental burden and is an innovative technology that increases the sustainability of electric vehicle batteries. DETAILED DESCRIPTION OF THE INVENTION

[0024] The heat insulating silicone composition and the method for producing the heat insulating silicone composition according to the present invention will be described in detail below.

[0025] (Thermal insulating silicone composition) The heat insulating silicone composition is a composition for forming a heat insulating cured product. The heat insulating silicone composition can be used as a potting agent for a specific substrate, such as the substrate of an electric or electronic device, a circuit chip, an in-vehicle component, or a battery component.

[0026] The temperature and procedure for curing the heat insulating silicone composition are not limited and can be selected appropriately depending on the intended use of the resulting cured product.

[0027] When the heat insulating silicone composition of the present invention is cured by an addition reaction, each component of the heat insulating silicone composition will be described in detail below.

[0028] (A: organopolysiloxane) Component (A) is the main component of the heat-insulating silicone composition and is an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule. The molar ratio of the total number of alkenyl groups bonded to silicon atoms in component (A) to the total number of Si-H groups contained in the entire heat insulating silicone composition [Si-H groups / alkenyl groups] is between 0.5 and 1.0.

[0029] There are no particular restrictions on the viscosity or degree of polymerization of component (A), and these can be selected depending on the required mixed viscosity of the heat-insulating silicone composition. For example, the viscosity at 25°C may be 10 mPa·s or more and 30,000 mPa·s or less. The organopolysiloxane can be used alone or in appropriate combination of two or more. This is the main component of the heat-insulating silicone composition and has an average of at least two, preferably 2 to 50, and more preferably 2 to 20 alkenyl groups bonded to silicon atoms per molecule.

[0030] The molecular structure of component (A) is not particularly limited and may be, for example, a linear structure, a linear structure with some branching, a branched structure, a cyclic structure, or a cyclic structure with branching. Of these, component (A) is preferably a substantially linear organopolysiloxane, and specifically may be a linear diorganopolysiloxane whose molecular chain is primarily composed of repeating diorganosiloxane units and whose molecular chain ends are capped with triorganosiloxy groups. Some or all of the molecular chain ends, or some of the side chains, may be silanol groups.

[0031] There are no particular restrictions on the position of the alkenyl group bonded to the silicon atom in component (A), and component (A) may be an organopolysiloxane having alkenyl groups bonded to silicon atoms at both molecular chain terminals. Organopolysiloxanes that have one alkenyl group at each end of the molecular chain have the advantage that they contain fewer alkenyl groups, which act as reaction sites for crosslinking reactions, and that they enhance the flexibility of the cured product of the heat insulating silicone composition. Organopolysiloxanes that contain alkenyl groups on both molecular chain side chains in addition to at both molecular chain terminals can improve crosslink density and increase the hardness of the cured product of the heat insulating silicone composition. The number of alkenyl groups in one molecule of component (A) can be determined appropriately depending on the required hardness of the cured product, the molecular weight of component (A), etc. The number of alkenyl groups in one molecule should be two or more, more preferably two to five, and most preferably two (one alkenyl group at each end of the molecular chain).

[0032] The alkenyl group may be bonded to either a silicon atom at a molecular chain terminal or a silicon atom at a non-terminal position (in the middle of the molecular chain), or may be bonded to both. Furthermore, the component (A) may be a polymer made up of a single siloxane unit, or a copolymer made up of two or more types of siloxane units.

[0033] The viscosity of component (A) at 25°C may be from 10 mPa·s to 30,000 mPa·s, preferably from 50 mPa·s to 1,000 mPa·s, and more preferably from 100 mPa·s to 500 mPa·s.

[0034] In order to adjust the viscosity (mixed viscosity) of the heat insulating silicone composition before curing, two or more types of alkenyl group-containing organopolysiloxanes with different viscosities can also be used.

[0035] Specifically, the average composition formula of component (A) is represented by the following general formula (1). R 1 a SiO (4-a) / 2 (1) (However, in formula (1), R 1 are the same or different unsubstituted or substituted monovalent hydrocarbon groups having 1 to 18 carbon atoms. a is 1.7 to 2.1. Also, a is preferably 1.8 to 2.5, more preferably 1.95 to 2.05.

[0036] In one embodiment, the R 1At least two of the monovalent hydrocarbon groups represented by the formula (I) are selected from alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, hexenyl, and cyclohexenyl, and the remaining groups are substituted or unsubstituted monovalent hydrocarbon groups having 1 to 18 carbon atoms, specifically alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, and dodecyl; It is selected from cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, xylyl, biphenyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl; and halogen-substituted or cyano-substituted alkyl groups in which some or all of the hydrogen atoms in these hydrocarbon groups have been substituted with halogen atoms, cyano groups, or the like, such as chloromethyl, 2-bromoethyl, 3,3,3-trifluoropropyl, 3-chloropropyl, and cyanoethyl.

[0037] R 1 In selecting R, two or more alkenyl groups are required, and vinyl, allyl, propenyl, isopropenyl, 2-methyl-1-propenyl, 2-methylallyl, and 2-butenyl groups are preferred, with vinyl being particularly preferred. 1 As the group, a methyl group and a phenyl group are preferred, and a methyl group is particularly preferred. 1 It is preferable that 70 mol % or more of the copolymer contains methyl groups in terms of the physical properties of the cured product and economic efficiency, and generally, copolymers containing 80 mol % or more of methyl groups are used.

[0038] The molecular structure of component (A) is dimethylpolysiloxane terminally terminated with dimethylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymer terminally terminated with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer terminally terminated with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer terminally terminated with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer terminally terminated with trimethylsiloxy groups, or the formula: (CH3)2ViSiO 1 / 2 Siloxane units represented by the formula: (CH3)3SiO 1 / 2 Siloxane units represented by the formula: SiO 4 / 2 (where Vi represents a vinyl group), organopolysiloxanes in which some or all of the methyl groups of these organopolysiloxanes have been substituted with alkyl groups such as ethyl groups, propyl groups, etc.; aryl groups such as phenyl groups, tolyl groups, etc.; or halogenated alkyl groups such as 3,3,3-trifluoropropyl groups, and mixtures of two or more of these organopolysiloxanes. However, from the viewpoint of increasing the elongation at break of the cured product by increasing the molecular chain length, linear diorganopolysiloxanes having vinyl groups at both molecular chain terminals are preferred.

[0039] These organopolysiloxanes may be commercially available or may be produced by methods known to those skilled in the art.

[0040] (B: Organohydrogenpolysiloxane) Component (B) is an organohydrogenpolysiloxane containing 0.0001 mol / g or more and 0.005 mol / g or less of hydrogen atoms bonded to silicon atoms. Component (B) is an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms in each molecule, and is a crosslinking component that forms a cured product through an addition curing reaction between the Si—H group and the alkenyl group.

[0041] The organohydrogenpolysiloxane of component (B) is represented by the following average composition formula (2). [ka] (In formula (2), R 2 are each independently a hydrogen atom, a hydroxyl group, or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, provided that each molecule contains two or more hydrogen atoms bonded to silicon atoms, a is an integer of 2 or more, b is an integer of 1 or more, c is an integer of 0 or more, and d is an integer of 0 or more. a+b+c+d is not particularly limited as long as it satisfies the viscosity range described below, and may be 5 or more and 600 or less, or 10 or more and 400 or less.

[0042] The viscosity of component (B) at 25°C may be from 1 mPa·s to 3,000 mPa·s, and is preferably from 10 mPa·s to 1,000 mPa·s.

[0043] (B) R bonded to silicon atoms in component 2 is another monovalent hydrocarbon group, specifically, the monovalent hydrocarbon group includes alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, neopentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, xylyl, biphenyl, and naphthyl; benzene and substituted hydrocarbon groups in which some or all of the hydrogen atoms in these hydrocarbon groups have been substituted with halogen atoms, cyano groups, etc., such as chloromethyl, 2-bromoethyl, 3,3,3-trifluoropropyl, 3-chloropropyl, chlorophenyl, dibromophenyl, tetrachlorophenyl, difluorophenyl, β-cyanoethyl, γ-cyanopropyl, β-cyanopropyl. Particularly preferred monovalent hydrocarbon groups are methyl and phenyl.

[0044] Component (B) may further contain one having an -SiOH group at some of the molecular chain terminals. In this case, the ratio of the number of silicon atoms having an OH group to the total number of terminal silicon atoms possessed by all organopolysiloxanes in component (B) is less than 5%, preferably less than 2%. If this ratio satisfies the above condition, the addition reaction will proceed sufficiently and a satisfactory cured coating will be obtained.

[0045] The hydrogen content (H content) of component (B) is 0.0001 mol / g or more and 0.005 mol / g or less, preferably 0.0002 mol / g or more and 0.005 mol / g or less, more preferably 0.0003 mol / g or more and 0.005 mol / g or less, and even more preferably 0.0004 mol / g or more and 0.005 mol / g or less.

[0046] Component (B) may function as a crosslinking agent. The crosslinking agent is preferably an organohydrogenpolysiloxane having five or more hydrosilyl groups, and may be one having 10 to 18 hydrosilyl groups. The organohydrogenpolysiloxane used as the crosslinking agent has at least two hydrosilyl groups on its side chain. The number of hydrosilyl groups at the molecular chain terminals can be from 0 to 2, but two is economically preferred. The molecular structure of the organohydrogenpolysiloxane may be linear, cyclic, branched, or a three-dimensional network structure. There are no particular restrictions on the position of the silicon atom to which the hydrogen atom is bonded, and it may be at the molecular chain terminal, non-terminal, or side chain. Other conditions, such as organic groups other than hydrosilyl groups, bonding positions, degree of polymerization, and structure, are not particularly limited, and two or more types of organohydrogenpolysiloxanes may be used.

[0047] The content of the component (B) is, for example, 30 parts by mass or more and 35 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B).

[0048] The hydrosilyl groups in component (B) may be located at the molecular terminals, in side chains, or both at the molecular terminals and in side chains. An organohydrogenpolysiloxane having hydrosilyl groups only at the molecular terminals may be mixed with an organohydrogenpolysiloxane having hydrosilyl groups only in side chains.

[0049] From the viewpoint of improving heat resistance, component (B) may also contain an organohydrogenpolysiloxane containing at least one aromatic group in the molecule. For economic reasons, the aromatic group is preferably a phenyl group. A mixture of an aromatic group-containing organohydrogenpolysiloxane and an aromatic group-free organohydrogenpolysiloxane may also be used.

[0050] (C: Organic resin hollow filler) Component (C) is a hollow filler made of organic resin. The organic resin hollow filler may be an organic resin hollow filler selected from, for example, polymers of vinylidene chloride, acrylonitrile, methacrylonitrile, acrylic acid esters, and methacrylic acid esters, or copolymers of two or more of these.

[0051] The organic resin hollow filler may have an average particle size of 15 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 20 μm to 80 μm. The average particle size is measured as the cumulative weight average value (D50) or median diameter using a particle size distribution measuring device using a laser diffraction method.

[0052] Component (C) or component (C) having an inorganic substance attached thereto has a true specific gravity of 0.1 to 0.3, preferably 0.11 to 0.25, more preferably 0.12 to 0.20, and even more preferably 0.12 to 0.18. By controlling the specific gravity of the filler, separation (floating) of the filler in the composition (first or second liquid) can be suppressed.

[0053] When the total amount of the components (A) and (B) is taken as 100 parts by mass, the content of the component (C) is 5 parts by mass or more and 25 parts by mass or less, or 7 parts by mass or more and 22 parts by mass or less, preferably 8 parts by mass or more and 20 parts by mass or less, more preferably 8 parts by mass or more and 16 parts by mass or less, and even more preferably 8 parts by mass or more and 14 parts by mass or less.

[0054] Component (C) may have an inorganic substance attached to at least a portion of its surface, such as calcium carbonate, zinc oxide, hydroxyapatite, or hydrous magnesium silicate.

[0055] The inorganic substance of component (C) may be subjected to an affinity surface treatment or a dispersibility surface treatment, for example, with an organic substance such as a fatty acid or a resin acid.

[0056] Coating the organic resin hollow filler with an inorganic substance can prevent the filler from separating (floating) in the heat insulating silicone composition (first or second liquid). Since the first or second liquid of the low-viscosity heat insulating silicone composition tends to cause the filler to float during storage, this can be prevented by adjusting the specific gravity of the filler or by applying a surface treatment.

[0057] (D: Addition reaction catalyst) The addition reaction catalyst of component (D) is an addition reaction catalyst that promotes the addition curing reaction between the alkenyl group bonded to the silicon atom in component (A) and the hydrogen atom bonded to the silicon atom in component (B), and is a catalyst known to those skilled in the art. Component (D) includes platinum group metals such as platinum, rhodium, palladium, osmium, iridium, and ruthenium, as well as those formed by immobilizing these on a fine particle support material (e.g., activated carbon, aluminum oxide, or silicon oxide). Further examples of component (D) include platinum compounds such as platinum halides, platinum-olefin complexes, platinum-alcohol complexes, platinum-alcoholate complexes, platinum-vinylsiloxane complexes, dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, and cyclopentadiene-platinum dichloride.

[0058] From an economical standpoint, metal compound catalysts other than the platinum group metals mentioned above may be used as component (D). Examples of hydrosilylation iron catalysts include iron-carbonyl complex catalysts, iron catalysts having a cyclopentadienyl group as a ligand, iron catalysts having a terpyridine-based ligand, iron catalysts having a terpyridine-based ligand and a bis(trimethylsilylmethyl) group, iron catalysts having a bisiminopyridine ligand, iron catalysts having a bisiminoquinoline ligand, iron catalysts having an aryl group as a ligand, iron catalysts having a cyclic or acyclic olefin group having an unsaturated group, and iron catalysts having a cyclic or acyclic olefin group having an unsaturated group. Other examples include hydrosilylation cobalt catalysts, vanadium catalysts, ruthenium catalysts, iridium catalysts, samarium catalysts, nickel catalysts, and manganese catalysts.

[0059] The amount of component (D) used is an effective amount depending on the desired curing temperature and curing time for the application, but the concentration of the catalytic metal element relative to the total mass of the heat-insulating silicone composition is preferably in the range of 0.5 ppm to 1,000 ppm, more preferably 1 ppm to 500 ppm, and even more preferably 1 ppm to 100 ppm. If the amount is less than 0.5 ppm, the addition reaction will be significantly slower, while if the amount exceeds 1,000 ppm, costs will increase and this is economically undesirable.

[0060] The content of the (D) component may be 0.05 parts by mass or more and 1.8 parts by mass or less, and preferably 0.08 parts by mass or more and 1.6 parts by mass or less, when the total amount of the (A) component and the (B) component is 100 parts by mass.

[0061] (E: Silicone resin) Component E is a silicone resin having a number average molecular weight of 1,000 or more and having at least one alkenyl group in the molecule. The silicone resin may be a modified silicone resin, or may be a mixture of a resin not containing alkenyl groups and an organopolysiloxane containing alkenyl groups.

[0062] Examples of silicone resins include methyl silicone resins and methyl phenyl silicone resins. Examples of modified silicone resins include alkyd-modified, epoxy-modified, acrylic-modified, and polyester-modified resins.

[0063] Component (E2) may be the same as the alkenyl group-containing organopolysiloxane of component (A) described above.

[0064] (silica) The insulating silicone composition is preferably free of silica (silicon dioxide).

[0065] (adhesion aid) The heat insulating silicone composition does not include an adhesion promoter. The adhesive aid is preferably an organosilicon compound or organosiloxane having an organic functional group in its molecule. The organic functional group is preferably a silicon-bonded alkoxy group. Examples of the silicon-bonded alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the silyl group containing an alkoxy group bonded to a silicon atom include alkyldialkoxysilyl groups such as methyldimethoxysilyl, ethyldimethoxysilyl, methyldiethoxysilyl, and ethyldiethoxysilyl. In this case, the silicon atom may be bonded via another group such as an alkylene group. Examples of organic groups that can be contained as other groups include alkenyl groups such as vinyl groups, (meth)acrylic groups, hydrosilyl groups, isocyanate groups, epoxy groups, alkyl groups, aryl groups, etc. Preferably, the organic silicon compound or organosiloxane has at least one organic group (e.g., epoxy group, alkyl group, aryl group, etc.) and at least two or more silicon-bonded alkoxy groups.

[0066] When an epoxy group is contained as another organic group, it may be a linear or branched alkyl group having 1 to 20 carbon atoms or an epoxy group having an aromatic ring, and may contain 2 to 3 epoxy groups per molecule. Examples of the epoxy group-containing group include groups bonded to a silicon atom in the form of a glycidoxyalkyl group such as a glycidoxypropyl group, or an epoxy-containing cyclohexylalkyl group such as a 2,3-epoxycyclohexylethyl group or a 3,4-epoxycyclohexylethyl group. Specific examples of the adhesion promoter include vinyltrimethoxysilane, tetraethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, oligomers of 3-glycidoxypropyltrimethoxysilane, oligomers of 3-glycidoxypropyltriethoxysilane, methacryloxysilanes such as 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, and furandione such as dihydro-3-(3-(triethoxysilyl)propyl)-2,5-furandione.

[0067] The heat-insulating silicone composition of the present invention may further contain optional components other than components (A) through (E) above, including additives conventionally known for silicone rubbers and gels, provided that the objectives of the present invention are not impaired. Examples of such additives include crosslinkers, organosilicon compounds or organosiloxanes (also known as silane coupling agents) that generate silanols upon hydrolysis, reaction rate modifiers, condensation catalysts, pigments, dyes, cure inhibitors, heat resistance additives, flame retardants, antistatic agents, conductivity additives, airtightness improvers, radiation shielding agents, electromagnetic wave shielding agents, preservatives, stabilizers, organic solvents, plasticizers, and fungicides. These optional components may be used singly or in combination.

[0068] (F: Reaction rate adjuster) Reaction rate modifiers are capable of adjusting the curing rate of the addition reaction, and examples thereof include acetylene compounds, hydrazines, triazoles, phosphines, and mercaptans. Any curing inhibitor known in the art to have a curing inhibitory effect can be used. Examples of such compounds include phosphorus-containing compounds such as triphenylphosphine, nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole, sulfur-containing compounds, acetylene compounds, compounds containing two or more alkenyl groups, hydroperoxy compounds, and maleic acid derivatives. Silane and silicone compounds containing amino groups may also be used. In particular, in the present invention, it is preferable that the curing proceeds at room temperature while minimizing the influence on flowability. In this case, the viscosity is low (for example, 100 mPa·s or less), and examples include various "ene-yne" systems such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; acetylenic alcohols such as 3,5-dimethyl-1-hexyn-3-ol, 1-ethynyl-1-cyclohexanol, and 2-phenyl-3-butyn-2-ol; well-known dialkyl, dialkenyl, and dialkoxyalkyl fumarates and maleates; and cyclovinylsiloxanes.

[0069] (G: Pigment) Examples of pigments include titanium oxide, alumina silicate, iron oxide, zinc oxide, calcium carbonate, carbon black, rare earth oxides, chromium oxide, cobalt pigment, ultramarine, cerium silanolate, aluminum oxide, aluminum hydroxide, titanium yellow, barium sulfate, precipitated barium sulfate, and the like, and mixtures thereof. The amount of pigment to be blended is an effective amount depending on the desired curing temperature and curing time for the application, but the amount of pigment component is usually in the range of 0.001% to 5% of the total mass of the heat-insulating silicone composition. The range is preferably 0.01% to 2%, and more preferably 0.05% to 1%. If the blending amount is less than 0.001%, the coloring is insufficient, making it difficult to visually distinguish between the first and second liquids. On the other hand, if the blending amount exceeds 5%, the cost increases and is therefore economically undesirable.

[0070] (I: Dispersant) A dispersant may be used to highly disperse component (C) in the system and prevent re-aggregation. Preferred dispersants include organopolysiloxanes containing organic functional groups within their molecules. Examples of organic functional groups include carboxyl groups, amino groups, alkyl groups, hydrosilyl groups, isocyanate groups, epoxy groups, aryl groups, polyether groups, polyglucoside groups, methoxy groups, ethoxy groups, and propoxy groups. Organopolysiloxanes containing at least one organic group (e.g., carboxyl groups, amino groups, epoxy groups, polyether groups, etc.) at the terminal or side chain are more preferred. Preferred examples of silyl groups containing alkoxy groups bonded to silicon atoms include alkyldialkoxysilyl groups such as methyldimethoxysilyl groups, ethyldimethoxysilyl groups, methyldiethoxysilyl groups, and ethyldiethoxysilyl groups. In this case, the silicon atom may be bonded via another group such as an alkylene group. The carboxyl-modified organopolysiloxane may be WACKER M 642 from Wacker Chemie, the non-reactive amino-modified organopolysiloxane may be WACKER FINISH WT 1270 from the same company, or the epoxy-modified organopolysiloxane may be WACKER SILICONFLUID 22254 VP from the same company.

[0071] As dispersants other than organosilicon compounds or organopolysiloxanes, titanate coupling agents having a hydrophobic group such as an alkyl group are preferred, and for example, triisostearoyloxy-isopropoxytitanium is preferred.

[0072] By using a dispersant having an organic functional group, the organic functional group interacts with the hydrophilic groups on the surface of component (C), helping to disperse component (C), thereby reducing the viscosity of the uncured heat-insulating silicone composition, and inhibiting re-aggregation of component (C) during storage, thereby inhibiting floating of component (C) and reducing the strength of the suspended matter, making it easier to re-agitate.

[0073] The content of component (I) may be 0.05 parts by mass or more and 2 parts by mass or less, preferably 0.08 parts by mass or more and 1.0 parts by mass or less, and more preferably 0.1 parts by mass or more and 0.5 parts by mass or less, when the total amount of components (A) and (B) is 100 parts by mass.

[0074] The heat insulating silicone composition of the present invention may also contain one or more compounds selected from the group consisting of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), tetradecamethylcycloheptasiloxane (D7), and hexadecamethylcyclooctasiloxane (D8). The total content of the above (D4), (D5), (D6), (D7), and (D8) may be less than 0.1 parts by mass (i.e., less than 1,000 ppm) when the total amount of the (A) component and the (B) component is 100 parts by mass. When the total content of (D4) to (D8) in the heat insulating silicone composition is within the above range, the flash point of the composition as a whole is high, improving safety during storage. Furthermore, it is possible to provide a cured product obtained by curing the composition that is less likely to cause contact problems with electronic components, etc. A heat insulating silicone composition in which the total content of the above (D4) to (D8) is less than 0.1 parts by mass when the combined amount of the components (A) and (B) is 100 parts by mass can be produced by using a component (A) in which the total content xA of the components (D4) to (D8) is less than 0.1 parts by mass, and a component (B) in which the total content xB of the components (D4) to (D8) is less than 0.1 parts by mass, such that xA + xB < 0.1 parts by mass. The contents of (D4) to (D8) are measured by gas chromatography. The measurement conditions for gas chromatography may be appropriately selected according to a conventionally known method.

[0075] (2 liquid type) In this embodiment, the heat insulating silicone composition may be a two-component type that begins to harden when a first component and a second component are mixed. The first liquid contains components (A), (C), and (D). The first liquid may further contain a reaction rate modifier, a pigment, and a dispersant. Each of the components (A), (C), and (D), the reaction rate modifier, and the pigment in the first liquid may be one type or two or more types. The second liquid contains components (A), (B), (C), and (E). Each of the components (A), (B), (C), and (E) in the second liquid may be one type or two or more types. The second liquid may further contain a dispersant. Neither the first nor second liquid contains silica or an adhesive aid.

[0076] [1st liquid] For a total of 100 parts by mass of the first liquid, Component (A) is 80 parts by mass or more and 96 parts by mass or less, Component (C) is 5 parts by mass or more and 15 parts by mass or less, Component (D) is 0.1 parts by mass or more and 0.5 parts by mass or less, The reaction rate adjuster (F) is 0.1 parts by mass or less, Pigment (G) 0.2 parts by mass or less Dispersant (I) is 0.5 parts by mass or less That's fine too.

[0077] [Second liquid] For a total of 100 parts by mass of the second liquid, Component (A) is 24 parts by mass or more and 36 parts by mass or less, Component (B) is 55 parts by mass or more and 65 parts by mass or less, Component (C) is 8 parts by mass or more and 10 parts by mass or less, Component (E) is 0 parts by mass or more and 2.5 parts by mass or less Dispersant (I) is 0.5 parts by mass or less That's fine too.

[0078] For a total blend amount of 100 parts by mass of the two-component heat insulating silicone composition, The first liquid is 40 parts by mass or more and 60 parts by mass or less, The second liquid is 60 parts by mass or more and 40 parts by mass or less That's fine too.

[0079] (Method for producing heat-insulating cured product) The method for producing the heat-insulating cured product obtained by curing the heat-insulating silicone composition of the present invention includes the following steps: a step of mixing a first liquid and a second liquid to produce a heat insulating silicone composition; a step of potting (filling or applying) the heat insulating silicone composition onto a substrate; The method includes a step of curing the potted layer at a temperature of 5° C. or higher and 100° C. or lower, more preferably 15° C. or higher and 50° C. or lower, for a predetermined period of time. The curing conditions are preferably room temperature curing. Rapid curing can also be performed at a temperature higher than room temperature. However, it is preferable to set the curing temperature and curing time so that component (C) does not shrink or deform. The curing time depends on the curing temperature, and the higher the curing temperature, the shorter the curing time.

[0080] (base material) Examples of the substrate include various electric and electronic parts, automobile parts, various computer-related parts such as PCs and mobile terminals, battery units, electric devices, and electronic devices. The electrical and electronic devices are not particularly limited, and examples thereof include mobile phones, smartphones, tablets, smartwatches, computers, semiconductor package substrates, electronic circuit boards, LED package substrates, sensor substrates, imaging element substrates, liquid crystal substrates, and organic EL substrates.

[0081] A heat insulating silicone composition can be potted into the gaps between the substrates and cured. A heat insulating silicone composition can be potted into the gaps between the components of the substrate and cured.

[0082] <Example> Examples of two-liquid mixed type will be described below. However, the present invention is not limited to the following examples. Table 1 shows various conditions for the components of the first liquid. Table 2 shows various conditions for the components of the second liquid.

[0083] [Table 1]

[0084] [Table 2]

[0085] Table 3 shows the blending ratio of each component in the first liquid for Examples 1 to 15, and Table 4 shows the blending ratio of each component in the second liquid. Table 5 shows the blending ratio of each component when the first and second liquids for Examples 1 to 15 are mixed. Table 6 shows the evaluation results for Examples 1 to 15. The blending ratio values ​​indicate parts by mass. The organic resin hollow filler is a polymer whose main components are acrylonitrile, methyl methacrylate, and methacrylonitrile.

[0086] [Table 3]

[0087] [Table 4]

[0088] [Table 5]

[0089] [Table 6]

[0090] <Comparative Example> Table 7 shows the blending ratios of each component in the first liquid of Comparative Examples 1 to 6, and Table 8 shows the blending ratios of each component in the second liquid. Table 9 shows the blending ratios of each component when the first and second liquids of Comparative Examples 1 to 6 are mixed. Table 10 shows the evaluation results of Comparative Examples 1 to 6. The numerical values ​​for blending ratios indicate parts by mass.

[0091] [Table 7]

[0092] [Table 8]

[0093] [Table 9]

[0094] [Table 10]

[0095] (Manufacturing method) The first and second liquids shown in the examples and comparative examples were mixed together to produce the compositions. For example, 40 wt% of the liquid material in the composition (Liquid 1 or Liquid 2) and the entire amount of filler are placed in a planetary mixer and mixed for 2 minutes at a revolution speed of 660 rpm and a rotation speed of 220 rpm.Then, the remaining liquid material (60 wt%) is added and mixed for 2 minutes at the same speed as above. Next, the first liquid and the second liquid were mixed in a mass ratio of 1:1. Next, various evaluations were carried out on the uncured and cured state. The evaluation methods (measurement methods) for the various evaluations are shown below.

[0096] (Theoretical specific gravity) The theoretical specific gravity is determined from the specific gravity of each component and their blending ratio.

[0097] (molar ratio) The molar ratio [Si—H groups / alkenyl groups] is the molar ratio of the total number of alkenyl groups bonded to silicon atoms in component (A) to the total number of Si—H groups contained in the entire heat insulating silicone composition.

[0098] (thermal conductivity) The thermal conductivity of the heat-insulating cured product was measured at 25°C in accordance with ISO 22007-2. The heat-insulating silicone composition was cured at 100°C for 30 minutes. Two test pieces, each 40 mm in diameter and 10 mm in height, were used to sandwich a sensor and measure the thermal conductivity (W / mK) using a TPS-500 measuring instrument (manufactured by Hot Disk).

[0099] (penetration) The penetration of the heat-insulating cured product at 23°C was measured in accordance with ASTM D 2240. The heat-insulating silicone composition was cured in a 60 mL container at 100°C for 30 minutes, and the penetration of the cured product was measured using an automatic penetration / consistency meter (PENETROMETER RPM-101). The penetration is expressed as the length of a standard steel needle that penetrates into a sample at a constant temperature. A 100 g load was applied, and the penetration length was measured over 5 seconds. The value is the needle penetration depth, expressed in 1 / 10 mm units.

[0100] (density) The density of the heat insulating cured product was measured at 23°C in accordance with JIS K 6249. The heat insulating silicone composition was cured at 100°C for 30 minutes, and the density (g / cc) of a test piece was measured using a density meter (AUTOMATIC DENSIMETER, MODEL DSG-1) by the underwater displacement method. The difference (%) from the theoretical specific gravity was calculated.

[0101] (viscosity) The viscosity of the heat insulating silicone composition at 25°C was measured in accordance with JIS K 7117-2. The uncured heat insulating silicone composition was placed between a fixed plate and a 25 mm diameter cone rotating at an angle of 1° or 2°, and the viscosity was measured using a Physica MR 301 viscometer (manufactured by Anton Paar) at a shear rate of 10 (1 / s) and a gap of 0.106 mm. In Table 6, "First Liquid (D=10)" indicates the viscosity of the first liquid at a shear rate of 10 (1 / s), "Second Liquid (D=10)" indicates the viscosity of the second liquid at a shear rate of 10 (1 / s), and "Mixed (D=10)" indicates the viscosity at a shear rate of 10 (1 / s) when the first and second liquids are mixed.

[0102] (tensile strength) The tensile strength of the heat-insulating cured product at 25°C was measured in accordance with JIS K 6251. The heat-insulating silicone composition was cured at 100°C for 30 minutes, and a 2 mm-thick sheet was punched out into a No. 3 dumbbell shape. The breaking strength (kPa) and elongation (displacement %) were measured when pulled at a tensile speed of 500 mm / min using a tensile tester (Shimadzu Autograph AGS-X).

[0103] (Easy to float) Put 40wt% of the first or second liquid material and the entire amount of filler into a planetary mixer and mix for 2 minutes at a revolution speed of 660 rpm and a rotation speed of 220 rpm.Then add the remaining liquid material (60wt%) and mix for 2 minutes at the same speed as above. The uncured heat-insulating silicone composition was then allowed to stand for a certain period of time, after which the ease of the filler floating was determined from the position of the interface between the liquid phase (silicone phase) and the filler phase (component C phase).The material (part 1 or part 2) was poured into a 50 mL container with a diameter of 35 mm and a height of 78 mm, up to a filling height of 55 mm from the bottom, and after storage at high temperature for a specified time (for example, 1 week at 50°C), the position of the interface between the silicone phase and the filler phase was measured with a ruler or similar, and the ease of the filler floating was determined from the position of the interface and the amount of filler filled. The volume fraction of the blended amounts of component C and other components in the heat insulating silicone composition (first or second liquid) was determined. Theoretical liquid height H0 = liquid volume fraction (6 / 10) x 55 mm (filling height) After storing at high temperature for a predetermined time, the height H1 of the liquid phase was measured with a ruler. Floatability (%) = H1 / H0. In Table 6, "Liquid phase height 1st liquid" and "Difference between liquid phase height and theoretical value 1st liquid" indicate the evaluation results for the 1st liquid, while "Liquid phase height 2nd liquid" and "Difference between liquid phase height and theoretical value 2nd liquid" indicate the evaluation results for the 2nd liquid.

[0104] (Intensity of floating matter) After evaluating the ease of lifting, the strength of the filler (component C) floating on the surface of the sample was measured. The maximum load (N) when a spherical compression tool with a diameter of φ12.7 mm was pressed against the sample at a compression speed of 240 mm / min was measured using a compression tester (Shimadzu Autograph AGS-X). In Table 6, "Test force 1st liquid" indicates the strength results for the 1st liquid, and "Test force 2nd liquid" indicates the strength results for the 2nd liquid.

[0105] (Volume change rate) The heat insulating silicone composition was cured at 100°C for 30 minutes, and the weight and density of a 40mm diameter, 10mm high test piece was measured to calculate the volume (before heat shrinkage). The weight and density of the test piece, which had been heated in an oven at 200°C for 2 hours and then cooled to room temperature, were measured to calculate the volume (after heat shrinkage). The volume change rate (%) was calculated from the difference in volume before and after heating. Volume change rate = (volume after heat shrinkage - volume before heat shrinkage) / volume before heat shrinkage × 100 [%]

[0106] (Evaluation of Examples) In Example 1, by adjusting the polymer viscosity and molar ratio (Si-H group / alkenyl group), the hardness, viscosity, floatability, and suspended matter strength were improved compared to the comparative example, and the volume change rate (shrinkage) was also greater. In Example 2, the silicone resin (component E) was not included as compared with Example 1, and instead the amount of component A was increased, thereby improving the tensile strength and displacement. In Example 3, a silicone resin different from that used in Example 1 was used, and as a result, the tensile strength and displacement were improved. In Example 4, a silicone resin different from that used in Example 1 was used, and as a result, the tensile displacement was improved. In Example 5, the amounts of components B and C were increased and the amount of component A was decreased compared to Example 1, resulting in an increased viscosity. In Example 6, a filler (component C) having the same particle size and specific gravity as in Examples 1 to 5 and having a hydrophobic surface (treated with fatty acid) was used instead, which resulted in a decrease in viscosity and made the filler more likely to float. In Example 7, the amounts of components B and C were increased and the amount of component A was decreased compared to Example 1, resulting in an increased viscosity. In Example 8, a different filler (talc surface treatment) was used in place of Examples 1 to 5, resulting in an increase in thermal conductivity and a decrease in viscosity. In Example 9, the thermal conductivity increased and the viscosity decreased by replacing the inorganic filler of Examples 1 to 5 with a resin filler having a large particle size and a large amount of inorganic matter attached. In Example 10, the tensile displacement was improved by replacing the filler in Example 1 with a resin filler having a smaller particle size and the same specific gravity. In Example 11, the viscosity was reduced by replacing the filler in Example 1 with a resin filler of the same particle size and low specific gravity, which made the filler more likely to float. In Example 12, the viscosity was reduced by replacing the filler with a resin filler having the same particle size as in Example 1 and a low specific gravity. Example 13 did not contain the silicone resin (component E) as compared to Example 11, and instead contained an increased amount of component A, thereby reducing the strength of the floating matter. In Example 14, the addition of carboxyl-modified silicone oil reduced the viscosity compared to Example 13, and the strength of the suspended matter also decreased. In Example 15, the viscosity was reduced compared to Example 13 by adding the non-reactive modified silicone oil, and the strength of the suspended matter was also reduced.

[0107] (Evaluation of Comparative Examples) In Comparative Example 1, the difference from the theoretical specific gravity was large at 3% or more. The tensile strength and displacement were small, and the flexibility was low. The strength of the suspended matter after storage was high, making it difficult to re-agitate. In Comparative Example 2, the molar ratio (Si—H group / alkenyl group) was increased from that in Example 1, and therefore the penetration was low. In Comparative Example 3, the molar ratio (Si—H group / alkenyl group) was increased from that in Example 1, and therefore the penetration was low. In Comparative Example 4, the component (B) was changed from Example 1 to an organohydrogenpolysiloxane having a hydrogen content of 0.005 mol / g or more, and the molar ratio (Si-H group / alkenyl group) was changed to 2 or more. Furthermore, an adhesive aid was added to Example 1. As a result, the hardness was high and the elongation was poor. In Comparative Example 5, the molar ratio (Si—H group / alkenyl group) was lowered from that in Example 1, and therefore the penetration was high. In Comparative Example 6, the resin filler used in Example 1 was changed to one with a higher specific gravity and a smaller particle size, and therefore the hardness and viscosity increased.

Claims

1. (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule; (B) an organohydrogenpolysiloxane containing 0.0001 mol / g or more and 0.005 mol / g or less of hydrogen atoms bonded to silicon atoms; (C) an organic resin hollow filler; (D) an addition reaction catalyst; A heat insulating silicone composition comprising: When the total amount of the component (A) and the component (B) is 100 parts by mass, The content of the component (C) is 5 parts by mass or more and 25 parts by mass or less, The content of the component (D) is 0.05 parts by mass or more and 1.8 parts by mass or less, the molar ratio of the total alkenyl groups bonded to silicon atoms in component (A) to the total Si—H groups contained in the entire heat-insulating silicone composition [Si—H groups / alkenyl groups] is 0.5 or greater and 1.0 or less; A heat insulating silicone composition.

2. The heat insulating silicone composition comprises: (E) a silicone resin having a number average molecular weight of 1,000 or more and 10,000 or less and having at least one alkenyl group in the molecule; The insulating silicone composition of claim 1.

3. The true density of the component (C) is 0.2 g / cm ３ The following, and / or The average particle size of the component (C) is 150 μm or less. The insulating silicone composition of claim 1.

4. the heat insulating silicone composition has a viscosity of 10,000 mPa s or less at 25°C; The insulating silicone composition of claim 1.

5. the heat insulating cured product obtained by curing the heat insulating silicone composition has a hardness (penetration) of 10 or more and 40 or less; The heat insulating silicone composition of claim 1.

6. The heat insulating cured product obtained by curing the heat insulating silicone composition exhibits a volume shrinkage of 15% to 34% after heating compared to before heating when heated at 190°C to 210°C for 1 to 2.5 hours. The heat insulating silicone composition of claim 1.

7. A method for producing a heat-insulating cured product obtained by curing the heat-insulating silicone composition according to any one of claims 1 to 6, comprising the steps of: potting the heat insulating silicone composition onto a substrate; curing the potted layer of the heat insulating silicone composition at a temperature of 5°C or higher and 100°C or lower; A method for producing a heat-insulating cured product.

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