Organopolysiloxane composition, cured product thereof, sealing agent for electronic component, electronic component, and method for protecting semiconductor chip

Abstract

The present invention relates to a hydrosilylation-curable organopolysiloxane composition, which contains: an organopolysiloxane and an organohydrogenpolysiloxane that are crosslinked by a hydrosilylation reaction; a non-reactive organopolysiloxane resin having a mass reduction rate of 2.0 mass% or less when exposed at 200 DEG C for 1 hour; and a reaction product of any alkali metal silanolate with at least one chloride and / or carboxylate of cerium. The composition provides a cured product which has low elastic modulus, low stress, high strength, cold resistance and excellent transparency, maintains these characteristics even under high-temperature conditions for a long period of time by adding a cerium compound, and is particularly less susceptible to cracking, peeling and the like even when a strong temperature gradient occurs inside the cured product.

Description

Technical Field

[0001] The present invention relates to an organopolysiloxane composition which, after curing, provides a cured product having excellent transparency and strength, and further relates to an organopolysiloxane composition which provides heat resistance, particularly an organopolysiloxane cured product having excellent crack resistance even when a temperature difference occurs inside a member at high temperatures, through a specific additive. In addition, the present invention also relates to an electronic component sealant containing the organopolysiloxane composition and an electronic component having the organopolysiloxane cured product. Background Art

[0002] A curable organopolysiloxane composition contains an organopolysiloxane formed by polymerization of siloxane units as a main agent, and becomes an organopolysiloxane cured product by reacting with a crosslinking agent or the like. A composition cured by a hydrosilylation reaction in a curable organopolysiloxane composition generally contains an organopolysiloxane having an alkenyl group such as vinyl bonded to a silicon atom, an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom (also referred to as a SiH group), and a hydrosilylation catalyst, and is a composition cured by an addition reaction between the SiH group and the alkenyl group (for example, Patent Documents 1 to 4). The curable organopolysiloxane composition can design the crosslink density of its cured product through the ratio of the SiH group to the alkenyl group or the like, thereby imparting desired physical / chemical properties to the cured product. In particular, an organopolysiloxane cured product having a low crosslink density, called "organosilicon gel", is mostly excellent in heat resistance, weather resistance, oil resistance, cold resistance, electrical insulation properties, etc., and has a low elastic modulus and low stress. Utilizing the characteristics of low elastic modulus and low stress that are not found in other materials such as various elastomers, the gel-like organopolysiloxane cured product is used as a sealing material for protecting electronic components such as in-vehicle electronic components, consumer electronic components, and display members, or for bonding members. In recent years, due to requirements for higher reliability of these members and the like, more excellent strength is required for organopolysiloxane materials containing gel-like organopolysiloxane cured products. In particular, since displays as in-vehicle components or small cameras for outdoor sports are exposed to strong or continuous vibrations, etc., the strength of the bonding part is required.

[0003] Furthermore, depending on the application, the cured organopolysiloxane is required to have higher cold resistance and heat resistance than before, and it is desired to improve the reliability including physical strength in a wide temperature range. As an example, in recent years, with the popularization of applications of electronic components that operate at high voltages / large currents for power control or conversion, which are called power devices, the operating temperature of these electronic components, especially silicon chips, has risen from about 150°C in the past to about 175°C. Furthermore, due to the popularization of SiC semiconductors, the requirement for an operating temperature of 200°C or higher is increasing. Therefore, methods have been proposed to improve the heat resistance of gel-like cured organopolysiloxanes used as protective materials in these devices by adding various heat-resistant additives (for example, Patent Documents 4 to 7). Among the cured organopolysiloxanes obtained by curing organopolysiloxane compositions containing these heat-resistant additives, there are also cured organopolysiloxanes that show only low elastic modulus heat resistance even when exposed to temperatures exceeding 200°C for a long time.

[0004] However, in order to ensure the reliability of power devices, it is not sufficient for the cured organopolysiloxane used to have only high heat resistance. The power semiconductor module used in a power device generates heat during its operation, but the heat source is the bottom surface of the module. Depending on the shape or structure of the device, only the vicinity of the bottom surface of the module is exposed to high heat in the cured organopolysiloxane used as a protective material, and sometimes a large temperature difference is generated within the same component. Such a temperature gradient caused by the temperature difference within the component generates internal stress as a difference in the expansion rate within the cured organopolysiloxane. In particular, there is the following problem: cracks (crazing or fissures) are generated in the cured organopolysiloxane along with the passage of time / thermal cycling, and its protective function deteriorates. The organopolysiloxane compositions described in Patent Document 4 and the like provide cured organopolysiloxanes with excellent elastic properties even at high temperatures exceeding 200°C, but there is still room for improvement in the technical problem of preventing cracks caused by the temperature difference within the component.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. Sho 48-017847

[0008] Patent Document 2: Japanese Patent Laid-Open No. Sho 56-143241

[0009] Patent Document 3: International Publication No. WO2015 / 034029

[0010] Patent Document 4: Japanese Patent Laid-Open No. Hei 08-225743

[0011] Patent Document 5: International Publication No. WO2015 / 111409

[0012] Patent Document 6: Japanese Patent Application Laid-Open No. 2018-053015

[0013] Patent Document 7: Japanese Patent Application Laid-Open No. 2021-011510 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] The present invention has been completed in view of the above circumstances, and its object is to solve the problems of storage, preservation, and reliability of an electronic component sealant composed of an organopolysiloxane composition and a bonding member for electronic components composed of a cured product of an organopolysiloxane composition. In addition, its object is to: improve the performance of an organopolysiloxane cured product obtained by curing an organopolysiloxane composition, that is, to improve the following problems: the strength of a conventional organopolysiloxane cured product does not meet the desired strength; the deterioration of the elastic modulus, stress, and high transparency due to long-term use at high temperatures; and further, cracks are likely to occur inside the organopolysiloxane cured product when a large temperature difference is generated inside the member. Further, the object of the present invention is to improve the insufficient strength or heat resistance of an organopolysiloxane cured product for electronic components, and the reduction in the reliability or service life of electronic components caused by its deterioration or the like.

[0016] Solutions to the Problems

[0017] The inventors of the present invention have conducted in-depth research and found that, in order to solve the above problems, it is effective to prepare a hydrosilylation reaction curable organopolysiloxane composition and use its cured product. The hydrosilylation reaction curable organopolysiloxane composition contains an organopolysiloxane resin that does not contain a low-molecular-weight siloxane oligomer, has a certain amount or more of branched siloxane units, and does not contain an alkenyl group in the composition. That is, the inventors of the present invention have found that the problems related to strength and adhesive strength in the above problems can be solved by using a curable organopolysiloxane composition containing: (A) an organopolysiloxane having a viscosity at 25°C in the range of 10 to 10,000 mPa·s and having an average of at least two alkenyl groups bonded to silicon atoms in one molecule; (B) a mass reduction rate of 2.0 mass% or less when exposed at 200°C for 1 hour, represented by the general formula:

[0018] (R 1 3 SiO 1 / 2 ) a (SiO 4 / 2 ) b (R 2 O 1 / 2 ) c

[0019] (In the formula, each R 1 is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms and not containing a carbon-carbon double bond, R 2 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and a, b, and c satisfy 0.35 ≤ a ≤ 0.55, 0.45 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.05, and a + b = 1) an organopolysiloxane resin; (C) a branched organohydrogenpolysiloxane having a viscosity at 25 °C in the range of 2 to 10,000 mPa·s and having at least two silicon-bonded hydrogen atoms in one molecule; and (D) a hydrosilylation curing catalyst. Further, it has been found that by adding (E) a reaction product of a specific amount of (e1) an alkali metal silanol compound and (e2) a cerium chloride salt or a carboxylate salt of cerium, problems related to heat resistance and cracks can be solved, thus completing the present invention. In addition, it has been found that by using an electronic component sealant or an adhesive composed of the organopolysiloxane composition, an organopolysiloxane cured product obtained by curing the organopolysiloxane composition, a bonding member composed of the same, and an electronic component further including these, the above problems can be solved, thus completing the present invention.

[0020] More specifically, the organopolysiloxane composition of the present invention contains, based on 100 parts by mass of the component (A): 10 to 80 parts by mass of the above component (B); the above component (C) in an amount such that the number of silicon-bonded hydrogen atoms is 0.5 to 2.0 per vinyl group bonded to a silicon atom in the whole composition; and a catalytic amount of the above component (D) sufficient to cause the reaction and curing of (A) to (C). Further, in the case where heat resistance is required, the composition contains 0 to 10.0 parts by mass of the above component (E). The component (E) may contain 0.5 to 5.0 mass% of cerium atoms or the like, and when added, the amount thereof may be such that the content of cerium atoms or the like in the component (E) is 0.005 to 0.15 mass% based on the whole organopolysiloxane composition.

[0021] In addition, the component (A) and the component (C) may be in the form of a branched chain, a straight chain, or a mixture thereof.

[0022] Further, the present invention provides an electronic component sealant containing the organopolysiloxane composition, particularly a sealant for power devices. The sealant may be substantially transparent. In addition, the present invention provides a bonding member for electronic components containing the organopolysiloxane composition.

[0023] The organopolysiloxane composition of the present invention is curable and can obtain a cured product through a hydrosilylation reaction. The present invention provides such an organopolysiloxane cured product. The organopolysiloxane cured product of the present invention is substantially transparent, and immediately after the curing reaction is completed, the direct reading value of the 1 / 4 consistency specified in JIS K2220 is in the range of 10 to 150. In the case of the cured product with improved heat resistance containing the (E) component in the present invention, even after being held at 225 °C for 1000 hours, it still maintains more than 50% of the direct reading value of the 1 / 4 consistency immediately after the curing reaction. The organopolysiloxane cured product can be used for protecting electronic components and maintaining adhesion. The organopolysiloxane cured product of the present invention can be substantially transparent.

[0024] The organopolysiloxane composition of the present invention and its sealing materials or bonding members can come into contact with electronic components such as semiconductors or be arranged around them, and can be cured by heating and the cured product can be arranged in situ. Therefore, the present invention provides an electronic component having such an organopolysiloxane cured product. In addition, if the electronic component is an optical component or optoelectronic component such as a light-emitting diode, a general lighting fixture, an optical member or an optoelectronic member having the organopolysiloxane cured product is provided. In particular, a semiconductor chip and a device having the same are provided. The semiconductor chip has an organopolysiloxane cured product containing the (E) component and is used in a harsh environment. The semiconductor chip includes a light-emitting semiconductor element such as an LED or a power semiconductor. The present invention particularly provides a power device having heat resistance / cold resistance.

[0025] Furthermore, the present invention provides a method for protecting a semiconductor chip using the organopolysiloxane composition of the present invention and its cured product. In particular, an application in the case where heat resistance and cold resistance are required is provided.

[0026] Effects of the Invention

[0027] The organopolysiloxane composition of the present invention is characterized in that after curing, it provides a cured product with excellent gel strength in essence and excellent mass productivity with reduced batch-to-batch deviation of the gel hardness measured by penetrometer, which is generally considered difficult. In addition, an organopolysiloxane cured product can be provided. If a cerium-containing component is added to the composition, it has excellent heat resistance and transparency at temperatures above 200 °C, can maintain a low elastic modulus, low stress and high transparency even after long-term use at high temperatures, and is not prone to cracking even in the case where a large temperature difference is generated inside the member over a long time, such as when a high-temperature heat source is only provided on the bottom surface of the cured product. Further, according to the present invention, an electronic component sealant composed of the composition and an electronic component having the organopolysiloxane cured product can be provided.

[0028] The cured product of the organopolysiloxane of the present invention has more excellent strength than the conventional cured product of organopolysiloxane. Therefore, when it is used as a sealant or a bonding member for electronic components such as in-vehicle electronic components, consumer electronic components, and display components, these components can be protected for a longer period and their reliability can be improved. Further, in the case where the cured product of the organopolysiloxane of the present invention imparting heat resistance is used for the protection of electronic components such as ICs or hybrid ICs, transparency is maintained even at a high temperature of 200 °C or higher required for SiC semiconductors, and at the same time, it has excellent strength, excellent heat resistance, and cold resistance. Therefore, an improvement in long-term durability can be expected. In addition, even under usage conditions where a large temperature difference is generated inside the organopolysiloxane cured product due to the configuration of heat sources or the like, or in outer space or extreme environments exposed to extreme or local temperature changes, problems such as cracks are difficult to occur, and deterioration over time is difficult to cause. Therefore, electronic components with high reliability and high durability under such usage conditions can be provided. Detailed Description of Embodiments

[0029] Hereinafter, each component will be described in detail. It should be noted that in this specification, the siloxane unit is sometimes represented as an M unit (A 3 SiO 1 / 2 ), a D unit (A 2 SiO 2 / 2 ), a T unit (ASiO 3 / 2 ), or a Q unit (SiO 4 / 2 ) according to the number of oxygen atoms of the siloxane adjacent to the silicon atom. Here, A is a group or atom other than -OSi. In addition, the viscosity is a value measured at 25 °C using a B-type viscometer in accordance with JIS K7117-1.

[0030] [Curable Organopolysiloxane Composition]

[0031] (A) Organopolysiloxane having an alkenyl group

[0032] (A) component is an organopolysiloxane having alkenyl groups and is one of the main components (base polymers) of the organopolysiloxane composition of the present invention. This organopolysiloxane contains on average at least two alkenyl groups bonded to silicon atoms (hereinafter, also referred to as "silicon atom-bonded alkenyl groups") in the molecule and has a viscosity in the range of 10 to 10,000 mPa·s at 25°C. More specifically, the (A) component is any one of the following (A-1) component and (A-2) component or a mixture of these, and further, an organopolysiloxane resin containing alkenyl groups may be optionally included as the (A-3) component. The (A-1) component can impart cold resistance to the organopolysiloxane cured product, and the (A-2) component can improve the strength of the organopolysiloxane cured product. Depending on the properties to be exhibited, the (A-1) component and the (A-2) component can also be combined. In addition, cold resistance can also be improved by combining with the (B) component described later, so the combination of these will also be described below.

[0033] (A-1) component is a branched organopolysiloxane and contains on average at least two alkenyl groups bonded to silicon atoms in the molecule. The (A-1) component may have a structure branched by a certain amount of RSiO 3 / 2 (wherein, R is a monovalent hydrocarbon group) units. The (A-1) component is preferably represented by the following average structural formula (1):

[0034] (R 3 SiO 1 / 2 ) d (R 2 SiO 2 / 2 ) e (RSiO 3 / 2 ) f (1)

[0035] In Formula 1, R represents a monovalent hydrocarbon group, and d, e, and f are positive numbers, and the percentages relative to the sum of d, e, and f satisfy 0.1 ≤ d ≤ 10.0, 80.0 ≤ e ≤ 99.8, and 0.1 ≤ f ≤ 10.0.

[0036] The branched organopolysiloxane of the (A-1) component has a specific amount of branched structure. Specifically, among all the siloxane units constituting the (A-1) component, the R 3 SiO 1 / 2 units are 0.1 mol% or more, 1.0 mol% or more, or 3.0 mol% or more and at the same time 10.0 mol% or less, and the R 2 SiO 2 / 2 units are 80.0 mol% or more and at the same time 99.8 mol% or less, 98.9 mol% or less, or 96.9 mol% or less, and RSiO 3 / 2The unit is 0.1% or more, 1.0% or more, or 3.0% or more in mole % and at the same time 10.0% or less. That is, the ratio of d∶e∶f in Formula 1 corresponds to the ratio of these mole %. By having such a branched structure in the (A-1) component, an organopolysiloxane cured product excellent in cold resistance at a particularly low temperature can be obtained. It should be noted that the above R 2 SiO 2 / 2 The ratio of the unit to the RSiO 3 / 2 unit to the R 3 SiO 1 / 2 The molar ratio of the unit is a value determined by nuclear magnetic resonance (NMR) measurement.

[0037] In the (A-1) component, the monovalent hydrocarbon group (i.e., the above R) bonded to the silicon atom in the siloxane structural unit is located on the side chain or the end of the main chain or the branched chain, and is i) an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, or ii) a monovalent alkenyl group. The (A-1) component has at least two alkenyl groups bonded to silicon atoms in the molecule.

[0038] When R is i) an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, its carbon number can be any integer in the range of 1 or more and at the same time 2 or less, 3 or less, 4 or less, 6 or less, 8 or less, 9 or less, or 10 or less. The carbon number of R is preferably a number in the range of 1 to 6. Specific examples of the unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond include: alkyl group; aryl group; aralkyl group; among them, methyl group, ethyl group, phenyl group, benzyl group, and further, from the aspect of easy synthesis, methyl group and phenyl group can be particularly exemplified. Or, a group in which a part or all of the hydrogen atoms of these groups are substituted by halogen atoms such as chlorine, bromine, and fluorine, for example, chloromethyl group, 3,3,3-trifluoropropyl group, etc. can be listed.

[0039] When R is ii) a monovalent alkenyl group, such an alkenyl group is an arbitrary integer in the range of 2 or more and at the same time 3 or less, 4 or less, or 6 or less, and is an alkenyl group having 2 to 4 or 2 to 3 carbon atoms. As specific examples thereof, vinyl group, allyl group, isopropenyl group, butenyl group, isobutenyl group, etc. can be listed, and vinyl group can be particularly exemplified.

[0040] In the above average structural formula (1) of the (A-1) component, the ratio of the alkenyl group bonded to the silicon atom among all the monovalent hydrocarbon groups R bonded to the silicon atom is 0.10% or more, 0.25% or more, or 0.50% or more in mole %, and can be at the same time 4.00 mole % or less or 2.00 mole %. It should be noted that the amount of the above alkenyl group is a value quantified by a Fourier transform near-infrared spectroscopic analyzer.

[0041] The viscosity of the component (A-1) at 25°C is in the range of 10 to 10,000 mPa·s, but it can be in the range of 10 to 5,000 mPa·s or 10 to 1,000 mPa·s at 25°C.

[0042] The branched organic polysiloxane as the component (A-1) can be synthesized by a known method with a desired viscosity and design structure. For example, it can be prepared as follows: According to the description in the examples of Japanese Patent Laid-Open No. 61-16295, etc., in the presence of potassium silanol, hydrolyzates of each siloxane unit having RSiO 3 / 2 , R 2 SiO 2 / 2 and R 3 SiO 1 / 2 and the hydrolyzates of ViR 0 2 SiOSiR 0 2 Vi and cyclic polysiloxane (R 0 2 SiO) y (In each formula, R is a monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond such as an alkyl group, and Vi is an alkenyl group such as a vinyl group) are heated to carry out equilibrium polymerization for preparation.

[0043] By including the above-mentioned amount of silicon atom-bonded alkenyl in the component (A-1), a so-called gel-like organic polysiloxane cured product having flexibility with a direct reading value of 10 to 150 for the 1 / 4 consistency specified in JIS K 2220 after curing can be obtained. In the present invention, "after curing" means leaving the curable organic polysiloxane composition standing at 80°C for 1 hour.

[0044] The component (A-1) having the above-mentioned viscosity helps to make the handling workability and fluidity of the organic polysiloxane composition of the present invention and the strength of the obtained cured product good. Here, the strength of the cured product refers to the degree to which the cured product can withstand without being damaged when stressed. That is, it can be said that the greater the stress that causes the destruction of the cured product, the higher the strength of the cured product. In the present invention, it is measured by the same method as the measurement of the adhesive strength. That is, when measuring the adhesive strength, when cohesive failure occurs without peeling, the cured product itself is destroyed to end the measurement. Therefore, the strength of the organic polysiloxane cured product as the object is represented by the value of the stress at which cohesive failure occurs in the adhesive strength test.

[0045] By using the component (A-1), the organic polysiloxane composition of the present invention provides an organic polysiloxane cured product that is excellent in cold resistance especially even at a low temperature below -40°C in addition to the above-mentioned strength.

[0046] The component (A-2) is a linear organopolysiloxane, and on average contains at least two alkenyl groups bonded to silicon atoms in the molecule. The component (A-2) preferably can be represented by the following average structural formula (2):

[0047] R 3 SiO(R 2 SiO) h SiR 3 (2)

[0048] (In formula (2), R represents the same monovalent hydrocarbon group as R in general formula (1) of the above-mentioned component (A-1), and is i) an unsubstituted or substituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond, or ii) a monovalent alkenyl group. h represents a positive number and is a number in the range of 100 or more, 150 or more, or 200 or more and at the same time 300 or less, 400 or less, or 500 or less.)

[0049] Among all the siloxane units constituting the component (A-2), the R 3 SiO 1 / 2 units are in an amount in the range of 0.1 mol% or more, 0.5 mol% or more, or 1.0 mol% or more and at the same time 10.0 mol% or less, 5.0 mol% or less, or 3.0 mol% or less, and the R 2 SiO 2 / 2 units account for the remainder thereof, that is, 90.0 mol% or more, 95.0 mol% or more, or 97.0 mol% or more and at the same time 99.9 mol% or less, 99.5 mol% or less, or 99.0 mol% or less. Here, the ratio of g:h in formula 2 corresponds to the ratio of these mol%. It should be noted that the ratio of the above-mentioned R 2 SiO 2 / 2 units to the R 3 SiO 1 / 2 units is a value obtained by measurement using nuclear magnetic resonance (NMR).

[0050] In the above average structural formula (2) of the component (A-2), the ratio of the alkenyl group bonded to the silicon atom among all the monovalent hydrocarbon groups R bonded to the silicon atom can be 0.25 mol% or more, 0.50 mol% or more, or 1.00 mol% or more, and at the same time 4.00 mol% or less, 3.00 mol% or less, or 2.00 mol%. It should be noted that the amount of the above-mentioned alkenyl group can be quantified using a Fourier transform near-infrared spectroscopic analyzer.

[0051] (The viscosity of the component (A-2) at 25 °C is in the range of 10 to 10,000 mPa·s, but at 25 °C it can be 1.0 or more or 5.0 or more, and at the same time can also be in the range of 5000 or less or 1000 or less mPa·s value.)

[0052] Due to the (A-2) component having the above structure, a flexible so-called gel-like organopolysiloxane cured product can be obtained, where the direct reading value of the 1 / 4 consistency specified in JIS K 2220 after curing is in the range of 10 to 150. Due to having the above viscosity, the (A-2) component contributes to good handling workability, fluidity of the organopolysiloxane composition of the present invention, and the strength of the obtained cured product.

[0053] Examples of the linear organopolysiloxane represented by the above average structural formula (2) include polymers composed of dimethylsiloxane. However, further, for example, polymers composed of methyltrifluoropropylsiloxane can be cited, or copolymers containing methylvinylsiloxane and / or diphenylsiloxane / phenylmethylsiloxane in any proportion in addition to dimethylsiloxane and / or methyltrifluoropropylsiloxane. In addition, both ends of these polymers are capped with dimethylethenylsilanoxy, methyldivinylsilanoxy, or trivinylsilanoxy, or one end is capped with trimethylsilanoxy and the other end is capped with dimethylethenylsilanoxy; copolymers capped with trimethylsilanoxy at both ends, containing vinylmethylsiloxane and dimethylpolysiloxane and / or methyltrifluoropropylpolysiloxane in any proportion, and further optionally containing diphenylsiloxane or phenylmethylsiloxane, etc.

[0054] Among the linear organopolysiloxanes exemplified above, the linear organopolysiloxane without phenyl, that is, the so-called dimethylpolysiloxane, has the effect of improving the mechanical strength of the cured product obtained by curing the organopolysiloxane composition of the present invention, but cannot impart cold resistance like the above (A-1) component. In contrast, copolymers containing phenyl such as dimethylsiloxane / diphenylsiloxane copolymers capped with dimethylethenylsilanoxy at both ends (so-called phenyl-containing organopolysiloxanes) contribute to cold resistance. Therefore, when cold resistance is not required, the (A-2) component containing only dimethylpolysiloxane can be used as the (A) component without adding the (A-1) component. However, in order to balance cold resistance and mechanical strength, it is only necessary to use the (A-1) component in combination and / or make the (A-2) component contain phenyl-containing polysiloxane. At this time, by controlling the content of phenyl in the composition to the amount described below, cold resistance can be imparted to the obtained cured product.

[0055] Regardless of (A-1) and (A-2), when using an organopolysiloxane containing a phenyl group as part or all of the component (A), the content of the phenyl group can be 1% or more, or 3% or more, and at the same time within the range of 10% or less, or 7% or less, in terms of mol% based on the total functional groups bonded to silicon atoms. This is because if the content of the phenyl group exceeds 10 mol%, the hardness of the organopolysiloxane cured product sometimes increases due to the phenyl group in the cured product, and the flexibility is impaired. Depending on the blending amount, it is sometimes difficult to form a low-hardness gel-like cured product required for stress relaxation characteristics. In addition, this is because when the content of the phenyl group is less than the above lower limit of 1 mol%, sufficient cold resistance sometimes cannot be imparted to the organopolysiloxane cured product having a dimethylpolysiloxane backbone.

[0056] It should be noted that regardless of the component (A-1) and the component (A-2), by using the so-called organopolysiloxane containing a phenyl group as the main agent and adding the so-called dimethylpolysiloxane, the mechanical strength of the organopolysiloxane cured product of the present invention can be improved. In this case, the content of the phenyl group in the curable organopolysiloxane composition is preferably within the range exemplified in the previous paragraph. In particular, if the content of the phenyl group exceeds the above upper limit, it is difficult to mutually dissolve with the dimethylpolysiloxane used in combination, and sometimes the uniformity of the whole composition is impaired.

[0057] Regarding the relationship between the amounts of the component (A-1) and the component (A-2), as described above, they can be used separately or in combination. However, from the viewpoint of being able to balance the cold resistance and mechanical strength of the obtained organopolysiloxane cured product, the dimethylpolysiloxane-based component (A-2) can be set to 2 to 150 parts by mass, or 2 to 100 parts by mass, relative to 100 parts by mass of the component (A-1). By setting the ratio within this amount range, the cold resistance of the obtained organopolysiloxane cured product can be improved, its physical properties can be improved, the operability of the organopolysiloxane composition before curing can be further improved, and it is also advantageous in terms of cost.

[0058] The component (A-3) as an optional component is an organopolysiloxane resin containing an alkenyl group, which is a resinous, i.e., an organopolysiloxane component having a three-dimensional branched structure. The component (A-3) contains on average at least two alkenyl groups in the molecule and is selected from the group consisting of R r SiO 3 / 2 (wherein R r is a monovalent organic group) and the siloxane units shown by SiO 4 / 2 and the total number of moles of the siloxane units is at least 20 mol% of all the siloxane units of the organopolysiloxane resin. R ris the same monovalent organic group as R in the general formula (1) of the component (A-1), that is, i) an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond, or ii) a monovalent alkenyl group, or a hydroxyl group.

[0059] In the present application, the description of the alkenyl group of the component (A-1) applies to the alkenyl group of the component (A-3). Such alkenyl groups can be exemplified by vinyl or hexenyl in particular. Since the alkenyl group has hydrosilylation reactivity, it is introduced into the crosslinking reaction for forming the organopolysiloxane cured product, and an effect of improving the mechanical strength of the obtained cured product can be expected.

[0060] As the group other than the alkenyl group among the groups bonded to the silicon atom in the component (A-3), a hydroxyl group or an unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond can be exemplified. The number of carbon atoms can be any integer in the range of 1 or more and simultaneously 2 or less, 3 or less, 4 or less, 6 or less, or can be 6 or more or 7 or more and simultaneously 8 or less, 9 or less, 10 or less, 12 or less, 16 or less, 18 or less, or 20 or less. Specific examples of the unsubstituted or substituted monovalent hydrocarbon group not containing an aliphatic unsaturated bond include: an alkyl group; an aryl group; an aralkyl group; or a group in which a part or all of the hydrogen atoms of these groups are substituted by halogen atoms such as chlorine, bromine, and fluorine, or an alkoxy group substituted by a hydroxyl group. Among them, methyl, ethyl, phenyl, and benzyl can be exemplified. Further, from the viewpoint of easy synthesis, methyl, phenyl, or 3,3,3-trifluoropropyl can be particularly exemplified. From the viewpoint of mutual solubility with other components contained in the composition, an alkyl group is preferred, and methyl is particularly preferred.

[0061] The addition amount when adding the component (A-3) is arbitrary, but based on the whole organopolysiloxane composition of the present invention, it can be added in a value exceeding 0.0, or in the range of 0.10 or more and simultaneously 10 or less, 7.5 or less, or 5.0 or less in terms of mass%. In addition to the above-mentioned components (A-1) and (A-2), by setting the amount of the component (A-3) within this range, the mechanical strength of the obtained organopolysiloxane cured product can be improved. It can be said that the effect of improving the mechanical strength by the addition amount of the component (A-3) can be significantly observed when the addition amount is 0.10 mass% or more. In addition, when it exceeds 10 mass%, the viscosity of the organopolysiloxane composition at 25 °C sometimes becomes too high, and further, the obtained cured product becomes too hard, so it is not preferred in practical use. (B) An organopolysiloxane resin having a low content of low-molecular-weight molecular species and not containing an alkenyl group

[0062] (B) The component is one of the main components of the present invention and is an organopolysiloxane resin not containing an alkenyl group. Specifically, it is composed of (R 13 SiO 1 / 2 )-shown siloxane unit (M unit) and the siloxane unit (Q unit) shown by (SiO 4 / 2 )-constituted organopolysiloxane resin called MQ resin. In the present invention, as described later, the content of the low-molecular-weight production reaction by-products of the component (B) is small, so the mass reduction rate when exposed at 200 °C for 1 hour is 2.0 mass% or less. The present invention is characterized in that the content of the low-molecular-weight production reaction by-products in this MQ resin is small.

[0063] (B) The organopolysiloxane resin of the component can be specifically shown by the following average structural formula (3):

[0064] (R 1 3 SiO 1 / 2 ) a (SiO 4 / 2 ) b (R 2 O 1 / 2 ) c (3)

[0065] (In the formula, a, b, c are 0.35 ≤ a ≤ 0.55, 0.45 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.05, and a + b = 1)

[0066] In the above average structural formula (3), each R 1 is an independent monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and the number of carbon atoms thereof can be 1 or more, and at the same time any integer within the range of 2 or less, 3 or less, 4 or less, 6 or less, 8 or less, 9 or less, or 10 or less. Its structure is a group selected from the group consisting of an alkyl group, an aryl group, and an aralkyl group, and specifically, methyl and phenyl can be exemplified. Here, 70 mol% or more of all R 1 in one molecule is an alkyl group having 1 to 10 carbon atoms. Specifically, the component (B) is exemplified as methyl. Further, from the viewpoints of industrial production and the technical effects of the invention, 88 mol% or more of all R 1 in one molecule is an alkyl group having 1 to 10 carbon atoms, and particularly methyl has attracted attention.

[0067] In addition, in the above formula (3), R 2 is a hydrogen atom or an alkyl group. In the case of an alkyl group, the number of carbon atoms thereof can be 1 or more and at the same time any integer within the range of 2 or less, 3 or less, 4 or less, 6 or less, 8 or less, 9 or less, or 10 or less. As the alkyl group of R 2 , the following can be exemplified: methyl, ethyl, propyl, butyl, pentyl, heptyl. The group R 2 containing this R 2 O1 / 2 is equivalent to a hydroxyl group or an alkoxy group, and its oxygen atom is bonded to the silicon atom of the siloxane unit.

[0068] In the above formula (3), a, b, and c respectively represent the siloxane unit represented by R 1 3 SiO 1 / 2 shown as the M unit, the siloxane unit shown by SiO 4 / 2 as the Q unit, or the ratio of the hydroxyl group or alkoxy group shown by R 2 O 1 / 2 shown.

[0069] In the above formula (3), a is a number in the range of 0.35 or more, 0.40 or more, or 0.45 or more and at the same time 0.60 or less, or 0.55 or less. If a is above the lower limit of the above range, the viscosity of the composition containing this component can be prevented from becoming too high. On the other hand, if a is below the upper limit of the above range, the mechanical strength (hardness, elongation, etc.) of the organopolysiloxane cured product obtained by curing the curable organosilicon composition of the present invention does not become too low.

[0070] In the above formula (3), b is a number in the range of 0.40 or more, or 0.45 or more and at the same time 0.7 or less, or 0.65 or less. If b is within the above numerical range, the viscosity of the composition containing this component will not become too high, and the cured product obtained by curing the composition can be a cured product with excellent mechanical strength.

[0071] In the above formula (3), c is sometimes 0, but in any case is a number in the range of 0.0 or more and at the same time 0.05 or less or 0.03 or less. If c is below the upper limit of the range, the composition containing this component exhibits excellent thermal curability.

[0072] Component (B) is generated by providing a balanced reaction of the raw materials for the Q unit constituting the resinous polymer part and the M unit as its terminal. Therefore, the molecular weight of component (B) can be controlled by the ratio of the M unit and the Q unit, that is, the values of a and b above. In the range of a and b above, the value measured by gel permeation chromatography (GPC) (based on polystyrene standard substance) using toluene as a solvent is in the range of 2,000 to 25,000.

[0073] The so-called MQ resin, which is the main molecular species of the component (B), can be synthesized by a known method with a desired molecular weight and designed structure. However, in the present invention, the MQ resin formulated in the composition is characterized in that the mass reduction rate when exposed at 200 °C and normal pressure for 1 hour is 2.0% by mass or less. The mass reduction under this condition is attributed to the presence of low molecular weight components that volatilize under this condition. In the production process of the component (B), when polymerizing an organopolysiloxane resin composed of M units and Q units, volatile low molecular weight components appear as by-products. This volatile low molecular weight component is referred to as "M" in this specification. 4 Q structure". If the M 4 Q structure is mixed into the organopolysiloxane composition of the present invention, it has the effect of significantly reducing the hardness of the organopolysiloxane cured product obtained by curing the organopolysiloxane composition. Depending on its content, the hardness of the obtained organopolysiloxane cured product changes significantly, and the change in the number of penetration, which represents hardness, is also obvious.

[0074] It is known that such M 4 Q structure will decrease or eventually disappear when the organopolysiloxane resin containing it is maintained at a temperature of 200 °C or higher. This means that if the organopolysiloxane cured product having an organopolysiloxane resin containing the M 4 Q structure as a part of its composition is aged at a temperature of 200 °C or higher, the M 4 Q structure gradually volatilizes, and through the progress of volatilization, the penetration of the organopolysiloxane cured product significantly decreases, that is, the hardness of the cured product increases. That is, if the MQ resin is manufactured by a known method, it contains an M 4 Q structure in a certain amount or more. Therefore, if an existing MQ resin without special refining is used to prepare the organopolysiloxane composition, the heat resistance characteristics of the cured product obtained by curing are deteriorated, especially over time. In addition, since the content of the M 4 Q structure is usually different between batches of MQ resin, when using such MQ resin in the curable organopolysiloxane composition, there is a problem of mass stability that the penetration of the obtained cured product varies with each batch. Therefore, the curable organopolysiloxane composition of the present invention is characterized by not containing the M 4 Q structure. For this purpose, it is necessary to remove the M 4 Q structure after synthesizing the organopolysiloxane resin of the component (B) and before the organopolysiloxane composition of the present invention is cured into a cured product.

[0075] In order to make the curable organopolysiloxane composition of the present invention not contain the M 4 Q structure, it is possible to remove the M after synthesizing the organopolysiloxane resin of the component (B) and before formulating it into the organopolysiloxane composition of the present invention.4 Q structure. As its methods, the following can be listed: in the manufacturing process of the organopolysiloxane resin, after the polymerization reaction, after obtaining the particulate organopolysiloxane resin as the crude raw material, drying it with an oven or the like; or a method of removing it together with the above-mentioned organic solvent using a twin-screw kneader, etc. More specifically, by heating an organopolysiloxane resin containing M at a high temperature of about 200°C 4 The organopolysiloxane resin containing the Q structure is treated for a certain period of time according to the surface area of the resin until no further mass reduction is observed, and volatile components can be removed. For example, when an organopolysiloxane cured product obtained by curing 1 g of an organopolysiloxane composition in an aluminum cup with a diameter of 50 mm is heated in an oven set at 200°C, its mass decreases for about 1 hour and then becomes constant. In addition, organic solvents and M 4 volatile components such as the Q structure can be removed simultaneously from the organopolysiloxane resin as component (B) using a twin-screw kneader set at 200°C. At this time, if it is set at around 200°C, the residence time in the twin-screw kneader is about 5 minutes. In addition, if the treated organopolysiloxane cured product is granular and heated to this temperature while stirring in the atmosphere, etc., since its surface area relative to the volume is large, the volatile low-molecular-weight M 4 The Q structure can be removed within a few minutes.

[0076] It should be noted that such an organopolysiloxane resin is manufactured by polymerization reaction in the presence of an organic solvent having high compatibility with the raw material monomers, and the organic solvent is removed by reduced-pressure drying or the like, whereby the organopolysiloxane resin as the product can be obtained. However, the M 4 The Q structure has higher compatibility with the organopolysiloxane resin than such an organic solvent and is difficult to remove under drying conditions where only the organic solvent is removed. In addition, since such an M 4 The Q structure is not generated in the production process of component (A), component (C), component (D), or any optional component (E) of the curable organosiloxane composition of the present invention, the curable organopolysiloxane composition of the present invention or its cured product and a composition containing an MQ resin containing the M 4 Q structure as the prior art instead of component (B) and its cured product can be distinguished by preheating these compositions or cured products at 150°C to volatilize organic solvents, etc., and then heating at 200°C to measure their mass reduction. Further, the volatile components can be identified by gas chromatography or the like. As described above, since the M 4 The Q structure itself is difficult to volatilize compared to solvents, etc., and thus cannot be removed by the general raw material preparation method. It is necessary to remove it through the steps within a specific process aimed at removing the M 4 Q structure as described above. In addition, the molecular weight is larger than that of M4 Compounds with a high Q structure, such as those composed of M 6 Q 2 or M Vi 4 The structure represented by Q does not volatilize at a temperature of about 200 °C. Therefore, it can be said that this step is specifically for removing M 4 The step of the Q structure. It should be noted that the monovalent vinyl-containing organosiloxane unit represented by ViR 3 2 SiO 1 / 2 is represented as the M Vi unit.

[0077] Relative to 100 parts by mass of component (A), component (B) can be exemplified as 10 to 80 parts by mass. More specifically, it can be exemplified as an amount within the range of 10 or more, 15 or more, 20 or more, 40 or more, or 50 or more and simultaneously 60 or less, 70 or less, or 80 or less. Specifically exemplified are the ranges of 10 to 80 parts by mass, or 15 to 80 parts by mass, 40 to 70 parts by mass. If component (B) is used within the above range, the amount of the M 4 Q structure that can enter the composition of the present invention is 1.0 part by mass or less, or 0.5 part by mass or less. Of course, the closer to 0 part by mass, the more preferable. By chromatographic formulation analysis of the composition of the present invention, the residual amount can be quantified based on the peak of the molecular weight of the M 4 Q structure.

[0078] (C) Organohydrogenpolysiloxane crosslinking agent

[0079] Component (C) is a crosslinking agent, which is an organohydrogenpolysiloxane having at least two silicon atoms bonded to hydrogen atoms (also represented as SiH groups) in one molecule. Through the reaction of the SiH groups of component (C) with the carbon-carbon double bonds contained in the above component (A) and other components in the presence of a hydrosilylation reaction catalyst, the organopolysiloxane composition of the present invention as a crosslinkable composition is cured.

[0080] (C) Component has a monovalent organohydrogensiloxane unit represented by HR 3 2 SiO 1 / 2 (represented as the M H unit. R 3 is independently a monovalent organic group), or a divalent organohydrogensiloxane unit represented by HR 3 SiO 2 / 2 (represented as the D H unit. R 3An organohydrogenpolysiloxane (independently a monovalent organic group) is sufficient. Its structure is not particularly limited and can be linear, branched, cyclic, or resinous. As a specific structure of the component (C), examples include a linear organohydrogenpolysiloxane containing only M H units, or a combination of linear and branched organohydrogenpolysiloxanes. Among them, when the organopolysiloxane cured product obtained by curing the curable organopolysiloxane composition of the present invention is used for applications requiring heat resistance, if unreacted SiH components remain in the system, there is a possibility of further crosslinking at high temperatures and a change in penetration. Therefore, compared with the D H units with low reactivity and not easily reactive with all SiH groups, it is preferable to use an organohydrogenpolysiloxane containing M H units with good reactivity and capable of rapidly reacting with all SiH groups in the system. It should be noted that the amount of hydrogen atoms bonded to silicon atoms in the component (C) can be measured using an infrared spectroscopic device.

[0081] (C) component may consist only of (C-1) linear organohydrogenpolysiloxane, or may be a mixture of (C-1) linear organohydrogenpolysiloxane and (C-2) branched organohydrogenpolysiloxane. Each component will be described below.

[0082] (C-1) The linear organohydrogenpolysiloxane of the component reacts with the above-mentioned (A) component and functions as a crosslinking agent for this composition. Such a linear organohydrogenpolysiloxane has hydrogen atoms (SiH groups) bonded to two silicon atoms in one molecule and has a viscosity in the range of 2 to 10,000 mPa·s. The (C-1) component has almost or no branched structure, and most of its structure is linear. In particular, it may have a linear structure, and examples include the positions of SiH groups at both ends of the chain. Such a (C-1) component can be represented by the following average structural formula (4):

[0083] (HR 3 2 SiO 1 / 2 ) 2 (R 3 2 SiO 2 / 2 ) v (4)

[0084] In formula (4), R 3 represents the same group as the monovalent hydrocarbon group i) without an aliphatic unsaturated carbon bond in the above-mentioned (B) component. From an industrial perspective, examples include a methyl group or a phenyl group. In addition, in the formula, v is a number of 1 or more, and preferably 2 + v is 500 or less. As a specific structure, examples include the following average structural formula:

[0085] (H(Me)2 SiO 1 / 2 )(Me 2 SiO 2 / 2 ) v1 (SiO 1 / 2 (Me) 2 H)

[0086] (where Me is methyl)

[0087] A straight-chain dimethylpolysiloxane having no branches and having the two ends of the molecular chain capped with dimethylhydroxysilyloxy groups. Here, v1 is a number in the range of 2.0 to 500 mPa·s or 2.0 to 150 mPa·s at 25°C. That is, v1 is an integer that is 1 or more and at the same time 50 or less, 100 or less, or 200 or less. In addition, the following chain-like organohydrogenpolysiloxanes can be exemplified. It should be noted that in the formula, Me and Ph represent methyl and phenyl, respectively, v2 is an integer from 1 to 100, and v3 is an integer from 1 to 50.

[0088] HMe 2 SiO(Ph 2 SiO) v2 SiMe 2 H

[0089] HMePhSiO(Ph 2 SiO) v2 SiMePhH

[0090] HMePhSiO(Ph 2 SiO) v2 (MePhSiO) v3 SiMePhH

[0091] HMePhSiO(Ph 2 SiO) v2 (Me 2 SiO) v3 SiMePhH

[0092] (C-1) The content of the chain-like organohydrogenpolysiloxane in the organopolysiloxane composition can be exemplified by: a quantity in the range where the number of hydrogen atoms bonded to silicon atoms exceeds 0, or the number is 0.1 or more and at the same time 1.5 or less, or 1.2 or less, relative to one alkenyl group of the component (A).

[0093] (C-1) component has a viscosity at 25 °C in the range of 2.0 to 10,000 mPa·s, but may also be in the range of 2.0 to 5000 mPa·s or in the range of 2.0 to 1000 mPa·s. The (C-1) component having such a viscosity contributes to good handling workability and fluidity of the organopolysiloxane composition of the present invention and the strength of the resulting cured product.

[0094] (C-2) component, a branched organohydrogenpolysiloxane, is used in combination with the above-mentioned (C-1) component, reacts with the above-mentioned (A) component, and functions as a crosslinking agent for this composition. In order to have a branched structure, such a branched organohydrogenpolysiloxane contains, in a proportion of at least 20 mol% of all the siloxane units in the molecule, the siloxane units represented by R 4 SiO 3 / 2 or SiO 4 / 2 shown. If the amount of these branched units is less than the above lower limit, the penetration of the resulting organopolysiloxane cured product may sometimes not be effectively adjusted.

[0095] In addition, the (C-2) component has at least three hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The SiH groups of the (C-2) component are 3 or more in one molecule, but may also be 4 or more, 5 or more, or 10 or more, and at the same time may be 500 or less, 200 or less, 100 or less, or 80 or less.

[0096] (C-2) component may be an organohydrogenpolysiloxane represented by the following average unit formula (5):

[0097] (R 4 3 SiO 1 / 2 ) j (R 4 2 SiO 2 / 2 ) k (R 4 SiO 3 / 2 ) m (SiO 4 / 2 ) n (R 5 O 1 / 2 ) p (5)

[0098] (In the formula, j, k, m, n, and p are numbers satisfying the following: 0.1 ≤ j ≤ 0.80, 0 ≤ k ≤ 0.5, 0 ≤ m ≤ 0.8, 0 ≤ n ≤ 0.6, 0 ≤ p ≤ 0.05, where m + n ≥ 0.2, and j + k + m + n = 1)

[0099] In the formula, each R 4Identical or different, they are monovalent hydrocarbon groups having 1 to 10 carbon atoms without aliphatic unsaturated carbon bonds or hydrogen atoms, where at least three Rs in one molecule 4 are hydrogen atoms. Regarding the monovalent hydrocarbon groups as Rs other than hydrogen atoms 4 , the number of carbon atoms is any integer in the range of 1 or more and at the same time 2 or less, 3 or less, 4 or less, 6 or less, or can be 6 or more or 7 or more, and can also be any integer in the range of 8 or less, 9 or less, or 10 or less. Unsubstituted or substituted monovalent hydrocarbon groups without aliphatic unsaturated bonds specifically include: alkyl groups; aryl groups; aralkyl groups; alkyl groups; aryl groups; aralkyl groups; or groups in which a part or all of the hydrogen atoms of these groups are substituted by halogen atoms such as chlorine, bromine, and fluorine. Among them, methyl, ethyl, phenyl, and benzyl can be exemplified. Further, from an industrial perspective and from the perspective of easy synthesis, methyl or phenyl can be particularly exemplified.

[0100] On the other hand, R 5 is a hydrogen atom or an alkyl group having 1 or more and at the same time any integer in the range of 2 or less, 3 or less, 4 or less, 6 or less, or can be 6 or more or 7 or more and at the same time an integer in the range of 8 or less, 9 or less, or 10 or less. That is, R 5 O 1 / 2 represents a hydroxyl group or an alkoxy group. As R 5 , hydrogen atom, methyl, or ethyl can be particularly exemplified. Therefore, as OR 5 , hydroxyl group, methoxy group, or ethoxy group can be exemplified.

[0101] In the formula, j, k, m, n, and p are numbers satisfying the following: 0.1 ≤ j ≤ 0.80, 0 ≤ k ≤ 0.5, 0 ≤ m ≤ 0.8, 0 ≤ n ≤ 0.6, 0 ≤ p ≤ 0.05, where m + n ≥ 0.2 and j + k + m + n = 1, and k = 0 is particularly exemplified. When this composition is used for heat-resistant applications, as an example resinous organohydrogenpolysiloxane resin as the (C-2) component, specifically, the following can be exemplified: M H MT resin, M H MTT H resin, M H MTQ resin, M H MQ resin, M H MTT H Q, M H Q resin. Here, these resins are indicated by the siloxane units they contain. For example, M H MTQ resin is a resin containing M units, M H units, T units, and Q units in any proportion. It should be noted that M units, M H units, T units, and Q units are as described above, TH The unit represents HSiO 3 / 2 . In particular, the (C-2) component may be composed of:

[0102] (H(CH 3 ) 2 SiO 1 / 2 ) j1 (SiO 4 / 2 ) n1

[0103] the M shown H Q resin. Here, j1 + n1 = 1, and examples thereof include 0.1 ≤ j1 ≤ 0.80 and 0.20 ≤ n1 ≤ 0.90.

[0104] The content of the (C-2) component may be exemplified by an amount of 0.05 to 0.8 SiH groups relative to one alkenyl group of the (A) component. More specifically, an amount in the range of more than 0.05, or more than 0.1 and simultaneously 0.8 or less, or 0.75 or less is particularly exemplified. By making the content of the (C-2) component in the organopolysiloxane composition within this range, the hardness can be effectively controlled within a range where the penetration of the organopolysiloxane cured product is not excessively reduced. If the SiH group contained in the (C-2) component is less than the above lower limit relative to one alkenyl group of the (A) component, it is difficult to adjust the penetration of the organopolysiloxane cured product due to this component.

[0105] The viscosity of the (C-2) component at 25 °C is in the range of 2.0 to 10,000 mPa·s, preferably in the range of 2.0 to 5000 mPa·s, and more preferably in the range of 2.0 to 1000 mPa·s. The addition of the (C-2) component having such a viscosity results in good handling workability, fluidity of the composition, and strength of the obtained cured product.

[0106] (C-2) component not only adjusts the penetration of the obtained organopolysiloxane cured product, but also has the effect of improving crack resistance (especially cracks / breakage, etc. based on internal stress caused by internal temperature differences). From the viewpoint of the physical properties including heat resistance / cold resistance and crack resistance of the organopolysiloxane cured product formed by curing the organopolysiloxane composition according to the present invention, the total number of hydrogen atoms bonded to silicon atoms in the (C-1) component and the (C-2) component is a number in the range of 0.7 or more, or 0.8 or more and simultaneously 1.2 or less, or 1.0 or less relative to 1.0 alkenyl groups contained in the whole composition.

[0107] (D) Catalyst for hydrosilylation reaction

[0108] Component (D) of the present invention is used as a catalyst for promoting the hydrosilylation reaction of the silicon atom-bonded alkenyl group in component (A) with the silicon atom-bonded hydrogen atom in component (C). Examples of component (D) include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts. Further examples include non-platinum-based catalysts such as iron, ruthenium, and iron / cobalt. However, from the perspective of significantly promoting the curing of this composition, platinum-based catalysts are specifically exemplified. This platinum-based catalyst can be appropriately selected from known catalysts, but is represented by a platinum-vinylsiloxane complex. The structure of the vinylsiloxane is not limited, but from the perspective of good stability of the complex, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane can be exemplified, and it is preferably added in the form of a solution of the vinylsiloxane of this complex. In addition, from the perspective of improving the operability and pot life of the composition, a particulate platinum-containing hydrosilylation reaction catalyst dispersed or encapsulated with a thermoplastic resin can also be used. These hydrosilylation reaction catalysts can be used alone or in combination of two or more.

[0109] In the case of a particulate platinum-containing hydrosilylation reaction catalyst dispersed or encapsulated with a thermoplastic resin, the platinum-based addition reaction catalyst as component (D) can also be a catalyst dispersed or encapsulated in a thermoplastic resin such as an organosilicon resin, a polycarbonate resin, or an acrylic resin, that is, thermoplastic resin particles containing a platinum-containing hydrosilylation reaction catalyst. In addition, part or all of component (D) can be a catalyst that first exhibits activity in the composition upon irradiation with high-energy rays, or can be a high-energy ray-activated catalyst or a photo-activated catalyst represented by (methylcyclopentadienyl)trimethylplatinum(IV), bis(2,4-pentanedionato)platinum(II), etc.

[0110] The blending amount of component (D) can be an effective amount, and can be appropriately increased or decreased according to the desired curing rate. However, for example, when it is a platinum-based catalyst, the amount in terms of platinum metal is usually in the range of 0.1 to 1,000 ppm, preferably 1 to 300 ppm, relative to the total mass of the composition. Even if the blending amount exceeds the upper limit of the above range, there is no superiority in terms of the curing rate, and it is economically disadvantageous from the perspective of the price (cost) of platinum.

[0111] (E) The reaction product of (e1) an alkali metal silanolate and (e2) at least one cerium salt selected from cerium chloride and carboxylates of cerium

[0112] (E) component is an optional component, and can be used when the organopolysiloxane composition and / or its cured product containing the organopolysiloxane composition of the present invention are used in applications requiring higher heat resistance. This reaction product as the (E) component is described together with its production method, for example, in JP-A-49-83744 and further in JP-A-60-240761. However, each component for producing the (E) component and their reactions are summarized as follows.

[0113] (e1) Alkali metal silanolates can further react to obtain an organopolysiloxane with a viscosity at 25 °C in the range of 10 to 10,000 mPa·s in a reaction product obtained by subjecting (e1-1) one or more cyclic organopolysiloxanes and (e1-2) an alkali metal hydroxide to a ring-opening reaction.

[0114] (e1-1) The cyclic organopolysiloxane of the component is not particularly limited. For example, cyclic organopolysiloxanes having the following general formula (6) can be cited.

[0115] [Chemical formula 1]

[0116]

[0117] In formula (6), R represents the same monovalent hydrocarbon group as R in the general formula (1) of the above (A) component, and s and t are each an integer from 0 to 8, where 3 ≤ s + t ≤ 8. Specifically, as the (e1-1) cyclic organopolysiloxane, in addition to hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), substances in which a part of these methyl groups is substituted by other hydrocarbon groups, hydrogen groups, or reactive groups such as (meth)acryloyloxy, carboxyl, vinyl, aminopropyl, etc. can also be used. In addition, mixtures of these various organopolysiloxanes can also be used.

[0118] The alkali metal hydroxide as the (e1-2) component is not particularly limited. For example, sodium hydroxide and potassium hydroxide can be cited. The amount of such (e1-2) component is usually 0.1 to 10 parts by mass relative to 100 parts by mass of the (e1-1) component, but is not limited thereto, and can be adjusted according to the reaction conditions.

[0119] (Component (e1-3)) The organopolysiloxane may be a conventionally known chain organopolysiloxane having a viscosity at 25 °C in the range of 10 to 10,000 mPa·s, and may include some branched chains within the range of remaining liquid at normal temperature. In addition, a monovalent hydrocarbon group (which may be a monovalent alkenyl group) that is unsubstituted or contains a substituent and is the same as the group exemplified as R in the general formula (1) of component (A) is bonded to the silicon atom of the siloxane unit. In addition, as the molecular chain ends of the organopolysiloxane, examples include those capped with a trialkylsiloxy group such as trimethylsiloxy, an alkenyldialkylsiloxy group such as vinyldimethylsiloxy, a dialkenylalkylsiloxy group such as divinylmethylsiloxy, a trivinylsiloxy group such as trivinylsiloxy, or a hydroxyl group, an alkoxy group, etc.

[0120] Regarding the viscosity of the organopolysiloxane of component (e1-3), the viscosity at 25 °C is 10 mPa·s or more, or 50 mPa·s or more, and at the same time is within the viscosity range of 1,000 mPa·s or 10,000 mPa·s. When the viscosity of component (e1-3) is 10 mPa·s or less, there is a problem that the amount of silicon evaporation at high temperature tends to increase and the mass change becomes large. The amount of component (e1-3) is not particularly limited, but is usually 0.1 to 10 parts by mass relative to 100 parts by mass of component (e1-1).

[0121] The reactions of components (e1-1), (e1-2), and (e1-3) for obtaining component (e1) are known from the aforementioned Japanese Patent Application Laid-Open No. Sho 60-240761, etc., and examples include adding component (e1-2) to component (e1-1) at room temperature to open the ring of component (e1-1), adding component (e1-3) thereto, and reacting under a nitrogen stream at 115 °C for 2 hours, for example.

[0122] The cerium salt of component (e2) refers to a chloride or carboxylate of cerium or a rare earth element mixture mainly composed of cerium. That is, it is a chloride represented by M 1 Cly and a carboxylate represented by (R 4 COO)yM 1 (wherein R 4 is the same or different monovalent hydrocarbon group, M 1 is cerium or a rare earth element mixture mainly composed of cerium, and y is 1 to 3 according to the valence of M 1 ). Examples of the carboxylic acid include 2-ethylhexanoic acid, naphthenic acid, oleic acid, lauric acid, stearic acid, etc. It should be noted that this M 1The chloride or carboxylate salt can be used as a solution in lower alcohols or organic solvents in terms of the ease of its operation. Examples of the lower alcohols include methanol or ethanol, and examples of the organic solvents include petroleum-based solvents such as dry cleaning oil (solvent oil), light petroleum, and petroleum ether; aromatic solvents such as toluene and xylene.

[0123] (e2) The amount of the component is, with respect to 100 parts by mass of the total amount of the above (e1) component, exemplified by M 1 The amount is 0.05 parts by mass or more, or 0.1 parts by mass or more, and at the same time is 5 parts by mass or less, or 3 parts by mass or less, but is not limited thereto, and can be adjusted according to the reaction conditions.

[0124] (E) The component, with respect to 100 parts by mass of the (A) component, can be added in an amount of 0.20 parts by mass or more, or 0.3 parts by mass or more, and at the same time in the range of 10.0 parts by mass or less, 5.0 parts by mass or less, or 0.5 parts by mass or less. More specifically, it is added in a small amount of about 0.2 parts by mass, 0.3 parts by mass, or 0.4 parts by mass. Further, regarding the addition amount of the (E) component, it can be exemplified that, with respect to the whole composition, the M 1 content in the (E) component is 0.005 or more, or 0.01 or more, and at the same time is in the range of 0.15 or 0.1 mass%. This M 1 mostly exists in the form of a silanol salt, which is a silicon-containing compound having at least one unit in which its M 1 atom is bonded to a silicon atom through an oxygen atom. However, even in other forms, it is measured as a substance contained in the (E) component. By setting the amount of the (E) component within this range, it is advantageous in terms of the heat resistance of the obtained organopolysiloxane composition. When the addition amount of the (E) component is less than 0.20 parts by mass, no effect of improving the heat resistance at high temperatures is found. On the contrary, when it exceeds 10 parts by mass, not only does the transparency of the organopolysiloxane cured product decrease, but also the cost of the organopolysiloxane composition increases, which is economically disadvantageous.

[0125] (E) The component can be obtained, for example, as follows: Dissolve the (e1) component obtained as described above in an appropriate solvent (e.g., isopropyl alcohol), dropwise add the solution of the (e2) component at room temperature, mix the (e1) and (e2) components, and then perform heat treatment at a temperature of 150 °C or higher. Filter and recover the solid reactant, and remove the solvent under reduced pressure and gentle heating. The heating temperature in the heat treatment can be in the range of 150 °C or higher, 200 °C or higher, or 250 °C or higher, and at the same time in the range of 310 °C or lower, 305 °C or lower, or 300 °C or lower. When the heating temperature is less than 150 °C, it is difficult to obtain a uniform composition. If it exceeds 310 °C, there is a problem that, for example, the thermal decomposition rate of the (e1-3) component becomes large.

[0126] The high-strength silicone oxide solidified product of the present invention further contains component (E), and maintains flexibility even under high-temperature conditions for a long time, continuously exhibiting the desired characteristics of a low elastic modulus and low stress. That is, if component (E) is added to the organopolysiloxane composition of the present invention, an organopolysiloxane solidified product can be formed that has excellent heat resistance and transparency at a high temperature exceeding 200 °C, maintains a low elastic modulus, low stress, and high transparency even when used at a high temperature for a long time, and has crack resistance.

[0127] Any other components

[0128] In the composition of the present invention, in addition to the above components (A) to (D) and component (E) as an optional component, within the scope not impairing the object of the present invention, for example, reaction inhibitors, inorganic fillers, organopolysiloxanes that do not contain hydrogen atoms bonded to silicon atoms and alkenyl groups bonded to silicon atoms, tackifiers, heat resistance imparting agents, flame retardancy imparting agents, thixotropy imparting agents, pigments, dyes, and other optional components can be formulated.

[0129] The tackifier is a component that improves the adhesiveness of the organopolysiloxane to a substrate or the like, and can be appropriately selected from substances generally known to those skilled in the art. The type and amount of the tackifier are preferably selected within the range of substances or amounts that do not reduce the transparency of the organopolysiloxane solidified product or cause curing inhibition. The organopolysiloxane solidified product of the present invention can be arbitrarily used within the range of an organopolysiloxane composition that provides substantially transparent and has a direct reading value of 200 or less for the 1 / 4 consistency specified in JIS K2220 when evaluated by the method described in the items of the examples of the present application. Examples of those to be added to the organopolysiloxane composition of the present invention include titanium compounds such as tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra(2-ethylhexyl) titanate, ethyl acetate titanate, and acetylacetone titanate; silanes represented by the general formula (R a O) z SiR b (4-z) (wherein R a represents an alkyl group or an alkoxyalkyl group, R b represents an unsubstituted or substituted monovalent hydrocarbon group, and z is 3 or 4) and their partial hydrolysis condensates or combinations thereof, particularly silane coupling agents such as methyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane. Here, the content of the above-mentioned tackifier is not limited and can be appropriately designed, but is usually in the range of 0.001 to 5% by mass based on the whole composition.

[0130] Reaction inhibitors are components used to inhibit the hydrosilylation reaction of organopolysiloxane compositions and can be appropriately selected from substances commonly known to those skilled in the art. For example, reaction inhibitors such as acetylene-based, amine-based, carboxylic acid ester-based, and phosphite-based can be cited. The addition amount of the reaction inhibitor is usually 0.001 to 5% by mass of the entire organopolysiloxane composition. In particular, for the purpose of improving the operability of the organopolysiloxane composition of the present invention, the following reaction inhibitors can be used without particular limitation: acetylene alcohol-based compounds such as ethynylcyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol; enyne compounds such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne; cycloalkenyl siloxanes such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; and triazole compounds such as benzotriazole, etc.

[0131] In order to further improve the mechanical strength, an inorganic filler can also be added. The type thereof is not particularly limited. However, in the case where the organopolysiloxane composition requires low viscosity and transparency, an inorganic filler is usually not formulated. In the case of formulation, if the amount is 20% by mass or less, especially 10% by mass or less, the cured product can be made transparent. In addition, if nano-particles are used, transparency can sometimes be maintained. Without considering transparency, for example, inorganic fillers such as fumed silica, crystalline silica, precipitated silica, hollow fillers, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, layered mica, carbon black, diatomaceous earth, glass fiber, etc.; fillers obtained by surface hydrophobization treatment of these fillers with organosilane compounds, organochlorosilane compounds, organosilazane compounds, low molecular weight siloxane compounds, etc. In addition, silicone rubber powder, silicone resin powder, etc. can also be blended.

[0132] [Preparation of Organopolysiloxane Composition]

[0133] The organopolysiloxane composition of the present invention can be prepared by mixing the above components (A) to (D) (in the case of formulating component (E) or any other arbitrary component, it also includes the arbitrary component) according to a conventional method. At this time, the components to be mixed can be divided into two or more parts as needed for mixing. For example, it can be divided into: a part composed of a part of component (A) and components (B), (C) and arbitrary components; a part composed of the remaining part of component (A) and component (D). After mixing them separately, these two parts are mixed to prepare. In particular, it is preferred that the reaction inhibitor described above is included as an arbitrary component in any part.

[0134] The mixing method of each component of the organosilicon composition may be a conventionally well-known method, and there is no particular limitation. Usually, a uniform mixture is formed by simple stirring. In addition, in the case of containing solid components such as inorganic fillers as optional components, mixing using a mixing device is more preferable. There is no particular limitation on such a mixing device, and examples thereof include single-screw or twin-screw continuous mixers, two-roll mills, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneading mixers, Henschel mixers, etc.

[0135] The organopolysiloxane composition thus obtained can be suitably used as a sealant for electronic components or an adhesive for displays. In particular, by using the organopolysiloxane composition containing component (E) as a sealant for semiconductor chips or an adhesive for displays, even in a harsh environment where excellent heat resistance is required after the composition is cured, it is possible to effectively protect the semiconductor chip or display without generating cracks for heat sources or local heating.

[0136] [Curing of the organopolysiloxane composition]

[0137] The organopolysiloxane composition of the present invention is cured by a hydrosilylation reaction at normal temperature or temperature conditions according to the use, thereby becoming a gel-like, i.e., an organopolysiloxane cured product having a hardness such that the direct reading value of the 1 / 4 consistency specified in JIS K2220 below is within the measurable range. The temperature conditions for curing are not particularly limited, but are generally in the range of 60°C to 150°C for practical use. The organopolysiloxane prepared in this way is also one aspect of the present invention.

[0138] [Organopolysiloxane cured product]

[0139] The cured product of the organopolysiloxane of the present invention has excellent mechanical strength and adhesion properties, and thus can be suitably used as an adhesive for displays that are scaled up in area and have a wide temperature range for reliability. In addition, by using the component (E) in combination, it has the following properties: excellent heat resistance and transparency at temperatures exceeding 200°C, and can maintain a low elastic modulus, low stress, and high transparency even after long-term use at high temperatures. Moreover, even when placed for a long time in a state where only one direction of the organopolysiloxane cured product is exposed to high temperature, such as when a high-temperature heat source is provided only on one surface (e.g., the bottom surface) of the organopolysiloxane cured product, it is not likely to cause defects such as cracks in the organopolysiloxane cured product due to the temperature difference and internal stress inside the component. When the component (E) is included, further, in the case of being used for protecting electronic components such as semiconductor chips, SiC semiconductor chips, ICs, hybrid ICs, and power devices, it has the following advantages: it not only maintains transparency at high temperatures, has excellent heat resistance and thus is expected to improve long-term durability, but also is not likely to deteriorate at low temperatures. Therefore, it can provide highly reliable and highly durable electronic components even under severe use conditions with a large temperature difference. In particular, electronic components having the organopolysiloxane cured product as a sealant or the like have high reliability and high durability even under severe use conditions with a large temperature difference. It should be noted that the semiconductor chips mentioned above include light-emitting semiconductor elements such as LEDs.

[0140] (1 / 4 consistency)

[0141] The cured product of the organopolysiloxane of the present invention is a cured product within the range where the direct reading value (the reading unit is 1 / 10 mm) of the 1 / 4 consistency specified in JIS K2220 is 10 or more, 20 or more, or 30 or more and simultaneously 150 or less, 120 or less, or 100 or less. The cured product of the organopolysiloxane having a direct reading value of the 1 / 4 consistency specified in JIS K2220 within such a range has characteristics of an organopolysiloxane cured product such as a low elastic modulus and low stress. When its penetration is less than 10, it is difficult to exhibit the characteristics of an organopolysiloxane cured product such as a low elastic modulus and low stress. When it exceeds 150, it is difficult to maintain the form of an organopolysiloxane cured product, resulting in flow. It should be noted that the "direct reading value of the 1 / 4 consistency" means that using a 1 / 4 consistency meter of JIS K2220, in the same way as the penetration test of the 1 / 4 cone specified in JIS K2220, the 1 / 4 cone is allowed to fall from the surface of the specimen, and the value of the depth at which the cone penetrates is read.

[0142] (Transparency)

[0143] The cured product of the organopolysiloxane of the present invention is preferably transparent, particularly when used for display applications. On the other hand, when used as a sealant for power devices or the like, it may be colored or the like, but it is preferably substantially transparent industrially. "Substantially transparent" means that the silicone gel composition that has been degassed in advance is gently poured into an aluminum cup to a thickness of 10 mm, visually confirmed to have no bubbles, and then heated at any temperature between 80°C and 150°C to obtain an organopolysiloxane cured product with a thickness of 10 mm. When viewed from the upper surface, it is transparent enough to visually see the bottom surface of the aluminum cup. The organopolysiloxane cured product has such transparency, and thus is useful as a sealant for semiconductors such as power devices and the like.

[0144] The cured product of the organopolysiloxane of the present invention imparts excellent durability to the electronic components equipped with it. Therefore, one aspect of the present invention is a method for protecting electronic components, and the method is as follows: 1) contacting the organopolysiloxane composition and its sealing materials or bonding members with electronic components such as semiconductors or arranging them around the electronic components; 2) curing the composition by heating and arranging the obtained cured product in situ. The heating also depends on the heat resistance of the electronic components and the base on which they are mounted, but it can be carried out in the range of about 80°C to 150°C until the composition loses fluidity.

[0145] In addition, one aspect of the present invention is an electronic component equipped with the above-mentioned organopolysiloxane cured product, and examples thereof include in-vehicle electronic components, consumer electronic components, and display components. The electronic component can be an optoelectronic component, and examples thereof include light-emitting semiconductor elements such as LEDs, and general lighting fixtures equipped with the light-emitting semiconductor elements are also part of the present invention. In particular, the electronic component equipped with the organopolysiloxane cured product containing the component (E) can be exposed to severe temperature changes such as outer space. In addition, an electronic component containing a power semiconductor, particularly a SiC semiconductor, or a device equipped with the same that is exposed to a high temperature of 200°C or higher and a cooling cycle is also one aspect of the present invention. Examples of power devices equipped with power semiconductors include motor control, conveyor motor control, power generation systems, or space transportation systems.

[0146] Examples

[0147] Hereinafter, the organopolysiloxane composition and the silicone cured product of the present invention will be described in detail by way of examples. It should be noted that the present invention is not limited to the description of the following examples as long as it does not exceed its gist. The viscosity in the examples is the value at 25°C.

[0148] [Generation of component (E)]

[0149] The (E) component is produced by the following method. A potassium silanol compound is prepared by subjecting a mixture of hexamethylcyclotrisiloxane and octamethylcyclotetrasiloxane to a ring-opening reaction with potassium hydroxide. 100 g of this potassium silanol compound is dissolved in 150 g of isopropyl alcohol, and while stirring it, a mixture of 2.5 g of anhydrous cerium chloride, 50 g of ethanol, and 50 g of methanol is added dropwise to carry out the reaction. After filtering the reaction mixture, the filtrate is heated to 40 - 50 °C under reduced pressure to distill off ethanol and methanol. Then, it is filtered again to prepare a pale yellow liquid reaction product. The cerium content in this reaction product is 1.4 mass%.

[0150] [Evaluation of Organopolysiloxane Composition and Organopolysiloxane Cured Product]

[0151] The transparency, 1 / 4 consistency, heat resistance, and crack resistance of the organopolysiloxane cured product of the present invention were measured as follows.

[0152] (Production of Organopolysiloxane Cured Product)

[0153] The organopolysiloxane composition was slowly poured into a 50 ml glass beaker until the height from the bottom of the beaker became 3 cm, and then heated at 80 °C for 1 hour to produce an organopolysiloxane cured product.

[0154] (Measurement of 1 / 4 Consistency)

[0155] In the same manner as the penetration test using a 1 / 4 cone specified in JIS K2220, using a 1 / 4 consistency meter of JIS K2220, the 1 / 4 cone was allowed to fall from the surface of the organopolysiloxane cured product as the object, and the depth of penetration of the cone (the unit of reading is 1 / 10 mm) was read and recorded as the "direct reading value".

[0156] (Heat Resistance of Organopolysiloxane Cured Product)

[0157] The organopolysiloxane cured product cured by the above method was left standing in an oven at 225 °C, taken out after 1000 hours, and naturally cooled to 25 °C at room temperature. Then, the 1 / 4 consistency of this organopolysiloxane cured product was measured, and the direct reading value (the unit of reading is 1 / 10 mm) was recorded as the 1 / 4 consistency.

[0158] (Crack Resistance of Organopolysiloxane Cured Product)

[0159] The organopolysiloxane cured product cured by the above method was left standing on a hot plate heated to 225 °C, and the appearance state of the organopolysiloxane was continuously observed through the beaker for 1000 hours. When cracks were confirmed to have occurred by visual observation within 1000 hours, the time was recorded.

[0160] (Mechanical strength / Adhesion strength of the cured organopolysiloxane)

[0161] Using two aluminum plates of 25 mm×75 mm×1 mm, the adhesion strength and mechanical strength were measured by the method specified in JIS K6850 / 1999. It should be noted that in the case where the test ends with the cohesive failure of the organopolysiloxane, the adhesion strength directly represents the mechanical strength of the organopolysiloxane.

[0162] [Examples 1 to 8 and Comparative Examples 1 to 13]

[0163] The components shown in Tables 1, 2, 3 and 4 below were uniformly mixed according to the compositions (parts by mass) shown in Tables 5 and 6 to prepare 21 organopolysiloxane compositions. These organopolysiloxane compositions were cured by the methods described in the respective evaluation methods, and the 1 / 4 consistency, heat resistance and crack resistance of the obtained cured organopolysiloxane were evaluated, and the results were integrated in Tables 5 and 6 below. It should be noted that SiH / Vi in the table represents the number of moles of hydrogen atoms bonded to silicon atoms in components (C-1) and (C-2) relative to 1 mole of vinyl contained in the total of components (A-1), (A-2) and (D). In addition, the platinum metal content of component (D) is expressed in ppm in the composition.

[0164] [Table 1]

[0165]

[0166] ※The weight average molecular weight (Mw) is the weight average molecular weight determined by gel permeation chromatography (GPC) method and converted to standard polystyrene.

[0167] [Table 2]

[0168]

[0169]

[0170] ★The volatile content is the amount of mass reduction expressed as % when about 1 g of the organopolysiloxane resin is weighed into an aluminum cup with a diameter of 50 mm and placed at 200 °C for 1 hour. As described above, this value is consistent with the amount of M 4 Q structural units remaining in component B.

[0171] [Table 3]

[0172]

[0173] *SiH content = content of hydrogen atoms bonded to silicon atoms

[0174] [Table 4]

[0175]

[0176] [Summary]

[0177] As shown in Table 5, in Examples 1 to 5 of the present application, the properties of the basic organopolysiloxane compositions of the present invention are shown. The cured products of these compositions contain the characteristic component (B) in the present invention. Compared with Comparative Examples 1 and 2 that do not contain a sufficient amount of component (B), high adhesive strength and mechanical strength are observed. Therefore, it can be known that the composition containing component (B) can provide a tougher organopolysiloxane composition. In addition, from Comparative Examples 3 and 4, the contribution of component (C) within the scope of the present invention to the properties can be confirmed. Further, Comparative Examples 5 and 6 have the same composition as Example 4 except that the component (B) contains volatile components, but the strength is relatively poor, the 1 / 4 consistency is high, and there are deviations. Therefore, the basic organopolysiloxane cured product of the present invention stably exhibits high strength, and thus can be suitably used for applications requiring strength. Table 6 shows Examples 6 to 8 and Comparative Examples further adding component (E) as an optional component. The heat resistance of the organopolysiloxane cured products obtained from these compositions and the crack resistance during long-term heating at 225 °C in one direction are generally good, and the 1 / 4 consistency after 1000 hours at high temperature also does not change significantly. However, the strength in the case of not containing component (B) as in Comparative Examples 7 to 11 is significantly worse. In addition, the compositions of Comparative Examples 12 and 13 have the same composition as Example 7 and Example 8 respectively except that the component (B) contains volatile components. However, since the component (B) is not the one with a mass reduction rate of 2.0% by mass or less when exposed at 200 °C for 1 hour, which is a feature of the present invention, the crack resistance is significantly worse.

[0178] Properties of the basic compositions

[0179] [Table 5]

[0180]

[0181] (*1) Calculated from the amount of the component that volatilizes at 200 °C contained in component B, i.e., M 4 Calculated from the amount of the Q structure body.

[0182] (*2) Since the failure mode of the adhesion test is all cohesive failure, the adhesive strength = the mechanical strength of the organopolysiloxane cured product.

[0183] Effect of component (B) in the heat-resistant organopolysiloxane composition containing component (E)

[0184] [Table 6]

[0185]

[0186] (*1) The component that volatilizes at 200 °C contained in Component B, namely M 4 is calculated from the amount of the Q structure.

[0187] (*2) All of the failure modes of the adhesion test are cohesive failures. Therefore, the adhesion strength = the mechanical strength of the organopolysiloxane cured product.

[0188] Industrial applicability

[0189] The organopolysiloxane cured product obtained from the organopolysiloxane composition of the present invention has strength and transparency. Therefore, examples thereof include sealants, protective materials, optical element sealants, adhesive members for displays, optical members or optoelectronic members for general lighting fixtures, lenses (including secondary optical lens materials provided outside an LED package) or light diffusion members, white reflector members, wavelength conversion members, optical waveguides or light guide members. When used as an optical member or an optoelectronic member, various functional filler materials (fluorescent, light-diffusing, light-transmitting, coloring, reinforcing filler materials, etc.) can be added to the organopolysiloxane composition of the present invention. The organopolysiloxane composition of the present invention can be used in the same manner as existing organopolysiloxane compositions having the same optical properties. Due to its high strength, it is excellent in protecting devices or components containing the organopolysiloxane composition and has improved reliability compared to existing organopolysiloxane compositions.

[0190] Furthermore, the organopolysiloxane cured product obtained from the organopolysiloxane composition of the present invention containing Component (E) is difficult to crack even when a high temperature is applied only from one direction in addition to the heat resistance of 200 °C or higher required for SiC semiconductor chips. Therefore, there is a high degree of freedom in circuit design including thermal management, and it is also suitable for use as a sealant or protective material for power devices that generate heat only from the lower part of the device, and can improve the durability and reliability of such power devices. Examples of such power devices that require heat resistance and crack resistance include general inverter control, servo motor control, motor control for machine tools / elevators, etc., motor control for electric vehicles, hybrid vehicles or railway conveyors, generator systems for solar / wind / fuel cell power generation, and space transportation systems used in space.

Claims

1. An organopolysiloxane composition, comprising: (A) An organopolysiloxane having on average at least two alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 °C in the range of 10 to 10,000 mPa·s: 100 parts by mass; (B) Having a mass reduction rate of 2.0% by mass or less relative to the mass of component (B) when exposed at 200 °C for 1 hour, represented by the following formula: (R 1 3 SiO 1 / 2 ) a (SiO 4 / 2 ) b (R 2 O 1 / 2 ) c (In the formula, each R 1 is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms and not containing an aliphatic carbon-carbon double bond; R 2 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; a, b, and c are numbers satisfying 0.35 ≤ a ≤ 0.55, b = 1 - a, and 0 ≤ c ≤ 0.05) of an organopolysiloxane resin: 10 to 80 parts by mass; (C) An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule and having a viscosity at 25 °C in the range of 2 to 10,000 mPa·s: an amount such that the number of hydrogen atoms bonded to silicon atoms is 0.5 to 2.0 per alkenyl group bonded to a silicon atom in the whole composition; (D) A catalyst for hydrosilylation reaction: an amount sufficient to cause the reaction and curing of (A) to (C); and optionally (E) A reaction product of (e1) an alkali metal silanolate and (e2) at least one salt selected from the chlorides represented by 1 Cl y and the carboxylates represented by (R 4 COO) y M 1 (wherein R 4 is the same or different monovalent hydrocarbon groups, M 1 is cerium or a rare earth element mixture mainly composed of cerium, and y is 1 to 3 according to the valence of M 1 ): 0 to 10 parts by mass.​​​​​​​​​​​​​​​​ 2. The organopolysiloxane composition according to claim 1, wherein, M 4 The content of the Q structure is 1.0 part by mass or less.

3. The organopolysiloxane composition according to claim 1 or 2, wherein, The component (A) is any one or a mixture of the following: (A-1) A branched organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, having a viscosity at 25 °C in the range of 10 to 10,000 mPa·s, and represented by the following general formula (1) (R 3 SiO 1 / 2 ) d (R 2 SiO 2 / 2 ) e (RSiO 3 / 2 ) f (1) (In the formula, each R independently represents a monovalent hydrocarbon group, at least two of all of them being alkenyl groups, and d, e, and f are numbers such that the percentages relative to the sum of d, e, and f satisfy 0.1 ≤ d ≤ 10.0, 80.0 ≤ e ≤ 99.8, and 0.1 ≤ f ≤ 10.0); and (A-2) A linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 °C in the range of 10 to 10,000 mPa·s.

4. The organopolysiloxane composition according to claim 3, wherein, Among all the monovalent hydrocarbon groups bonded to the silicon atom in the component (A-1), 0.25 to 4.00 mol% are alkenyl groups.

5. The organopolysiloxane composition according to any one of claims 1 to 4, characterized in that, The component (C) comprises: (C-1) A linear organohydrogenpolysiloxane having a viscosity at 25 °C in the range of 2 to 1,000 mPa·s and having two hydrogen atoms bonded to silicon atoms in one molecule: an amount such that the number of hydrogen atoms bonded to silicon atoms is more than 0 and 2.0 or less per alkenyl group bonded to a silicon atom in the whole composition; optionally (C-2) has a viscosity at 25 °C in the range of 2 to 1,000 mPa·s, has three or more hydrogen atoms bonded to silicon atoms in the molecule, and contains at least 20 mol% of all siloxane units of R 4 SiO 3 / 2 (wherein R 4 is a monovalent hydrocarbon group) or a branched organohydrogen polysiloxane of the siloxane unit represented by SiO 4 / 2 : The amount of hydrogen atoms bonded to silicon atoms is 0.1 to 0.8 per vinyl group bonded to a silicon atom in the whole composition.

6. The organopolysiloxane composition according to claim 1 or 2, wherein, The component (E) contains 0.5 to 5.0% by mass of M 1 atoms.

7. An electronic component sealant, comprising the organopolysiloxane composition according to any one of claims 1 to 6.

8. The electronic component sealant according to claim 7, which is substantially transparent.

9. An organopolysiloxane cured product, which is obtained by curing the organopolysiloxane composition according to any one of claims 1 to 6, and has a direct reading value of 1 / 4 consistency specified in JIS K2220 in the range of 10 to 150.

10. The organopolysiloxane cured product according to claim 9, which is substantially transparent.

11. An electronic component, which includes the electronic component sealant according to claim 7 or 8, or the organopolysiloxane cured product according to claim 9 or 10.

12. The electronic component according to claim 11, which is mounted on a power device.

13. The electronic component according to claim 11, wherein, the electronic component is an optoelectronic component.

14. The electronic component according to claim 13, which is mounted on a general lighting fixture, a component for a display, an optical component, or an optoelectronic component.

15. A method for protecting a semiconductor chip, characterized in that the organopolysiloxane composition according to any one of claims 1 to 6, the electronic component sealant according to claim 7, or the organopolysiloxane cured product according to claim 9 is used.

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