JP2023087838A - Organopolysiloxane composition, cured product of the same, electronic component sealing agent, electronic component, and semiconductor chip protecting method - Google Patents

Abstract

To provide a curable organopolysiloxane composition which enables production of a cured product that has low elastic modulus and low stress, excellent in strength, cold resistance and transparency, maintains the above features under a long-time high-temperature condition by addition of a cerium compound, and prevents cracking and peeling even when a strong temperature gradient occurs inside.SOLUTION: A hydrosilylated curable organopolysiloxane composition contains organopolysiloxane and organohydrogenpolysiloxane which are crosslinked by hydrosilylation reaction, a non-reactive organopolysiloxane resin having a mass reduction ratio when being exposed at 200°C for 1 hour of 2.0 mass% or less, and arbitrarily contains a reaction product of alkali metal silanolate, and at least one or more kinds of cerium chlorides and/or carboxylates.SELECTED DRAWING: None

Description

The present invention relates to an organopolysiloxane composition that cures to give a cured product that is excellent in transparency and strength, and furthermore has heat resistance, particularly crack resistance even when temperature differences occur inside the member at high temperatures due to specific additives. It relates to an organopolysiloxane composition that gives an organopolysiloxane cured product excellent in The present invention also relates to an electronic part sealant containing the organopolysiloxane composition and an electronic part provided with the organopolysiloxane cured product.

The curable organopolysiloxane composition contains, as a main component, an organopolysiloxane in which siloxane units are polymerized, and reacts with a cross-linking agent or the like to form an organopolysiloxane cured product. Among curable organopolysiloxane compositions, compositions that cure by hydrosilylation reaction are generally organopolysiloxanes having alkenyl groups such as vinyl groups bonded to silicon atoms, hydrogen atoms bonded to silicon atoms (SiH groups and a hydrosilylation catalyst, and cured by the addition reaction of the SiH group and the alkenyl group (for example, Patent Documents 1 to 4). The curable organopolysiloxane composition allows the crosslink density of the cured product to be designed by adjusting the ratio of SiH groups and alkenyl groups, etc., and imparts desirable physical and chemical properties to the cured product. In particular, many of the low-crosslinking density organopolysiloxane cured products called "silicone gels" are excellent in heat resistance, weather resistance, oil resistance, cold resistance, electrical insulation, etc., and have a low elastic modulus and low stress. . Taking advantage of this low elastic modulus and low stress, which are not found in other materials such as various elastomers, gel-like organopolysiloxane cured products are used in electronic parts such as automotive electronic parts, consumer electronic parts, and display members. It is used as a sealing material for protection or for bonding members together. In recent years, due to the demand for higher reliability of these members and the like, higher strength is required for organopolysiloxane materials including gel-like organopolysiloxane cured products. In particular, a display as an in-vehicle component and a small camera for outdoor sports are exposed to strong or continuous vibrations, so the strength of the bonded portion is required.

Furthermore, depending on the application, the cured product of organopolysiloxane is required to have higher resistance to cold and heat than ever before, and improvements in reliability, including physical strength, over a wide temperature range are desired. there is As an example, in recent years, with the widespread use of electronic components called power devices that operate under high voltages and large currents for power control and conversion, the operating temperature of these electronic components, especially silicon chips, has increased from the conventional 150°C. °C to about 175°C. Furthermore, with the widespread use of SiC semiconductors, an operating temperature of 200° C. or higher is often required. For this reason, methods have been proposed for improving the heat resistance of cured gel-like organopolysiloxanes used as protective materials in these devices by adding various heat-resistant additives (for example, Patent Documents 4 to 7). . An organopolysiloxane cured product obtained by curing an organopolysiloxane composition containing these heat-resistant additives may exhibit heat resistance sufficient to retain its low elastic modulus even when exposed to temperatures exceeding 200° C. for a long period of time. be.

However, in order to ensure the reliability of power devices, it is not sufficient for the cured organopolysiloxane to be used only to have high heat resistance. Power semiconductor modules used in power devices generate heat during operation, and the heat source is the bottom surface of the module. Only the vicinity of the bottom surface is exposed to high heat, and a large temperature difference may occur within the same member. The temperature gradient caused by such a temperature difference in the member generates internal stress as a difference in the expansion coefficient inside the cured organopolysiloxane product, and particularly with the passage of time/thermal cycles, cracks occur in the cured organopolysiloxane product. There is a problem that the protective function deteriorates due to the occurrence of cracks). The organopolysiloxane composition described in Patent Document 4 and the like provides an organopolysiloxane cured product that has excellent elastic properties even at high temperatures exceeding 200° C. However, it prevents the occurrence of cracks due to temperature differences within the member. There is still room for improvement with respect to this technical problem.

JP-A-48-017847 JP-A-56-143241 International Publication No. WO2015/034029 JP-A-08-225743 International Publication No. WO2015/111409 JP 2018-053015 A Japanese Patent Application Laid-Open No. 2021-011510

The present invention has been made in view of the above circumstances, and provides a method for storing, preserving, and storing an electronic component sealing agent comprising an organopolysiloxane composition and an electronic component bonding member comprising a cured product of the organopolysiloxane composition. The purpose is to solve the problem of reliability. In addition, the performance of the cured organopolysiloxane obtained by curing the organopolysiloxane composition has been improved. It is an object of the present invention to solve the problems of deterioration of modulus, stress and high transparency, and that cracks tend to occur inside the organopolysiloxane cured product when a large temperature difference occurs inside the member. A further object of the present invention is to improve the reliability of electronic parts and the deterioration of the duration of use due to insufficient strength and heat resistance of the cured organopolysiloxane used in electronic parts, and deterioration thereof. and

As a result of intensive studies, the inventors of the present invention have found that in order to solve the above problems, 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 is added to the composition. It has been found that it is effective to prepare a hydrosilylation reaction-curable organopolysiloxane composition containing, and use the cured product thereof. That is, the inventors of the present invention have found that (A) the viscosity at 25° C. is within the range of 10 to 10,000 mPa s, and the number of alkenyl groups bonded to silicon atoms on average per molecule is at least two. (B) a mass loss rate of 2.0% by mass or less when exposed at 200° C. for 1 hour, general formula (R ¹³ SiO _1/2 ) _a ( _{SiO 4/2} ) _b ( ^R2O1 _/2 ) _c
(wherein each R ¹ is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms and contains no carbon-carbon double bonds; R ² is a hydrogen atom or 1 to 10 carbon atoms; and the alkyl groups a, b, and c satisfy 0.35 ≤ a ≤ 0.55, 0.45 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.05, and a + b = 1) Organopolysiloxane resin, (C) a branched organohydrogenpolysiloxane having a viscosity in the range of 2 to 10,000 mPa·s at 25° C. and having at least two silicon-bonded hydrogen atoms in one molecule, (D) Among the above problems, the problems related to strength and adhesive strength can be solved by using a curable organopolysiloxane composition containing a catalyst for hydrosilylation curing, and (E) a specific amount of (e1) an alkali metal The inventors have found that the problems of heat resistance and crack generation can be solved by adding a reaction product of a silanol compound and (e2) a cerium chloride salt or a cerium carboxylate. In addition, an electronic component sealant or bonding agent comprising the organopolysiloxane composition, an organopolysiloxane cured product obtained by curing the organopolysiloxane composition, a bonding member comprising the same, and an electronic device comprising these The inventors have found that the above problems can be solved by the parts, and arrived at the present invention.

More specifically, the organopolysiloxane composition of the present invention contains 10 to 80 parts by mass of component (B) per 100 parts by mass of component (A), and 10 to 80 parts by mass of component (C). Component (D) is added in an amount such that the number of silicon-bonded hydrogen atoms is 0.5 to 2.0 per silicon-bonded alkenyl group, and (A) to (C) are reacted and cured. Sufficient catalytic amount, included. Furthermore, when heat resistance is required, the composition contains 0 to 10.0 parts by mass of component (E). Component (E) may contain 0.5 to 5.0% by mass of cerium atoms, etc., and when added, the amount of cerium atoms, etc. in component (E) relative to the entire organopolysiloxane composition. The content of may be 0.005 to 0.15% by mass.

Also, the components (A) and (C) may be branched, linear, or a mixture thereof.

Furthermore, the present invention provides an electronic component encapsulant, particularly a power device encapsulant, containing the organopolysiloxane composition. This encapsulant may be substantially transparent. Further, the present invention provides an electronic component lamination member containing the organopolysiloxane composition.

The organopolysiloxane composition of the present invention is curable, and a cured product can be obtained by a hydrosilylation reaction. The present invention provides this organopolysiloxane cured product. The organopolysiloxane cured product of the present invention is substantially transparent and has a direct reading value of 1/4 penetration defined by JIS K2220 within the range of 10 to 150 immediately after the completion of the curing reaction. In the case of the cured product with improved heat resistance containing the component (E) of the present invention, even after being held at 225 ° C. for 1000 hours, 50% or more of the direct reading value of 1/4 consistency immediately after the completion of the curing reaction is maintained. It is. The cured organopolysiloxane can be used for protection of electronic parts and maintenance of adhesion. The cured organopolysiloxane of the present invention may be substantially transparent.

The organopolysiloxane composition of the present invention and the encapsulant or bonding member thereof can be placed in contact with or around electronic components such as semiconductors, and cured by heating to place the cured product on the spot. Accordingly, the present invention provides an electronic component comprising such an organopolysiloxane cured product. If the electronic component is an optical component such as a light emitting diode or an optoelectronic component, the present invention provides a general lighting fixture, an optical member or an optoelectronic component comprising the organopolysiloxane cured product. In particular, the present invention provides a semiconductor chip that is used in a harsh environment and a device that includes the cured organopolysiloxane containing the component (E). The semiconductor chips include light-emitting semiconductor elements such as LEDs and power semiconductors, and the present invention particularly provides power devices having heat resistance and cold resistance.

Furthermore, a method for protecting a semiconductor chip is provided using the organopolysiloxane composition of the present invention and a cured product thereof. It also provides applications where heat resistance and cold resistance are particularly required.

After curing, the organopolysiloxane composition of the present invention has excellent intrinsic gel strength, and is mass-producible by suppressing lot-to-lot variations in gel hardness measured by penetration, which is generally considered difficult. It is characterized by giving a cured product that is excellent in In addition, when a component containing cerium is added to this composition, it has excellent heat resistance and transparency at high temperatures exceeding 200°C, and maintains low elastic modulus, low stress and high transparency even after long-term use at high temperatures. and even when a large temperature difference occurs inside the member for a long time, as typified by installing a high-temperature heat source only on the bottom surface of the cured product, cracks are unlikely to occur. An organopolysiloxane cured product can be provided. Further, according to the present invention, it is possible to provide an electronic component sealant comprising this composition and an electronic component comprising the organopolysiloxane cured product.

The organopolysiloxane cured product of the present invention has a strength superior to that of conventional organopolysiloxane cured products. When used on parts, it can protect those parts longer and improve their reliability. Furthermore, when the heat-resistant organopolysiloxane cured product of the present invention is used to protect electronic components such as ICs and hybrid ICs, it maintains transparency even at high temperatures of 200°C or higher, which is required for SiC semiconductors. In addition, since it is excellent in strength, heat resistance and cold resistance, improvement in long-term durability can be expected. Also, depending on the location of the heat source, problems such as cracks may occur under usage conditions where there is a large temperature difference inside the organopolysiloxane cured product, or in outer space or extreme environments where it is exposed to extreme or partial temperature changes. Since it is hard to cause deterioration over time, it is possible to provide an electronic component with high reliability and high durability even under such conditions of use.

Each component will be described in detail below. In this specification, the siloxane units are M units (A ₃ SiO _1/2 ), D units (A 2 SiO 2/2 ), D units (A ₂ SiO _2/2 ), It may be expressed as a T unit (ASiO _3/2 ) or a Q unit (SiO _4/2 ), where A is a group or atom other than -OSi. The viscosity is a value measured at 25° C. using a Brookfield viscometer in accordance with JIS K7117-1.

[Curable organopolysiloxane composition]
(A) Alkenyl Group-Containing Organopolysiloxane Component (A) is an alkenyl group-containing organopolysiloxane, 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 silicon-bonded alkenyl groups (hereinafter also referred to as "silicon-bonded alkenyl groups") in the molecule, and has a viscosity of 10 to 10,000 mPa·s at 25°C. Has a range of viscosities. More specifically, component (A) is any one of the following components (A-1) and (A-2) or a mixture thereof, and optionally alkenyl as component (A-3) A group-containing organopolysiloxane resin may also be included. The (A-1) component can impart cold resistance to the cured organopolysiloxane product, and the (A-2) component can improve the strength of the cured organopolysiloxane product. The (A-1) component and the (A-2) component may be combined depending on the properties desired to be expressed. In addition, since it is possible to improve the cold resistance by combining with the component (B) described later, these combinations will also be described below.

Component (A-1) is a branched organopolysiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule. The component (A-1) may have a branched structure with a certain amount of RSiO _3/2 (wherein R is a monovalent hydrocarbon group) units. Component (A-1) can be suitably represented by the following average structural formula (1):
(R ₃ SiO _1/2 ) _d (R ₂ SiO _2/2 ) _e (RSiO _3/2 ) _f (1)
In Formula 1, R represents a monovalent hydrocarbon group, d, e and f are positive numbers, respectively, and 0.1≤d≤10.0, 80.0≤e≤99.8, 0.1≤d≤10.0. It satisfies 1≦f≦10.0 and d+e+f=1. The degree of polymerization (DP) of component (A-1) is preferably 200 or less.

The branched organopolysiloxane of component (A-1) has a specific amount of branched structures. Specifically, among all the siloxane units constituting component (A-1), R ₃ SiO _1/2 units are 0.1 or more, 1.0 or more, or 3.0 or more as mol %, and at the same time 10 .0 or less, and the R ₂ SiO _2/2 units are 80.0 or more and 99.8 or less, 98.9 or less, or 96.9 or less, and the RSiO _3/2 units are mol % % is 0.1 or more, 1.0 or more, or 3.0 or more and 10.0 or less at the same time. That is, the d:e:f ratio in Formula 1 corresponds to these mol % ratios. When component (A-1) has such a branched structure, it is possible to obtain an organopolysiloxane cured product that is excellent in cold resistance, especially at low temperatures. The molar ratio of R ₂ SiO _2/2 units, RSiO _3/2 units, and R ₃ SiO _1/2 units is a value determined by nuclear magnetic resonance (NMR).

In component (A-1), the silicon-bonded monovalent hydrocarbon group in the siloxane structural unit (that is, R described above) is located at the side chain or end of the main chain or branched chain, i ) unsubstituted or substituted monovalent hydrocarbon groups containing no aliphatic unsaturation, or ii) monovalent alkenyl groups. Component (A-1) has an average of at least two silicon-bonded alkenyl groups in the molecule.

When R is i) an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturation, the number of carbon atoms is 1 or more and simultaneously 2 or less, 3 or less, 4 hereinafter may be any integer within the range of 6 or less, 8 or less, 9 or less, or 10 or less. The number of carbon atoms in R is preferably in the range of 1-6. The unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturation is specifically an alkyl group; an aryl group; an aralkyl group; groups, especially methyl group and phenyl group because of ease of synthesis. Alternatively, groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms such as chlorine, bromine and fluorine, such as chloromethyl and 3,3,3-trifluoropropyl groups.

When R is ii) a monovalent alkenyl group, such alkenyl group may have at least 2 carbon atoms and may simultaneously be any integer within the range of up to 3, up to 4, or up to 6 carbon atoms. It is an alkenyl group whose number is 2 to 4, or 2 to 3. Specific examples thereof include a vinyl group, an allyl group, an isopropenyl group, a butenyl group, an isobutenyl group and the like, and a vinyl group is particularly exemplified.

In the above average structural formula (1) of component (A-1), the proportion of silicon-bonded alkenyl groups in all monovalent hydrocarbon groups R bonded to silicon atoms is 0.10 or more in terms of mol %, and 0.10 or more. It may be 25 or more, or 0.50 or more, and at the same time, 4.00 mol or less, or 2.00 mol %. The amount of alkenyl groups described above is a value quantified using a Fourier transform near-infrared spectrometer.

The viscosity of the component (A-1) at 25°C is in the range of 10 to 10,000 mPa s, but in the range of 10 to 5,000 mPa s at 25°C, or in the range of 10 to 1,000 mPa s. may be within the range.

The branched organopolysiloxane, component (A-1), can be synthesized with a desired viscosity and designed structure by a known method. For example, a hydrolyzate having RSiO _3/2 , R ₂ SiO _2/2 , and R ₃ SiO _1/2 siloxane units according to the description of Examples in JP-A-61-16295, ViR ⁰ ₂ SiOSiR ⁰ ₂ Vi and cyclic polysiloxane (R ⁰ ₂ SiO) _y (wherein R is a monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond such as an alkyl group, and Vi is a vinyl group is an alkenyl group such as ) in the presence of potassium silanolate and is heated for equilibrium polymerization.

(A-1) Flexibility in which the direct reading value of 1/4 penetration specified in JIS K 2220 after curing is in the range of 10 to 150 due to the above amount of silicon-bonded alkenyl groups contained in component (A-1). It is possible to obtain a so-called gel-like organopolysiloxane cured product having a In the present invention, "completion of curing" means that the curable organopolysiloxane composition was allowed to stand at 80°C for one hour.

Component (A-1), having the viscosity described above, contributes to improving the handling workability and fluidity of the organopolysiloxane composition of the present invention and the strength of the resulting cured product. Here, the strength of the cured product is the degree to which the cured product withstands stress without being broken. That is, it can be said that the strength of the cured product increases as the stress that causes breakage of the cured product increases. In the present invention, this was measured by the same method as the measurement of adhesive strength. That is, when cohesive failure occurs without peeling when measuring the adhesive strength, the cured product itself is destroyed and the measurement ends, so the stress value at which cohesive failure occurred in the adhesive strength test Expresses the strength of siloxane cured products.

By using the component (A-1), the organopolysiloxane composition of the present invention can provide an organopolysiloxane cured product which, in addition to the strength described above, has excellent cold resistance even at low temperatures below -40°C. can be done.

Component (A-2) is a straight-chain organopolysiloxane containing on average at least two silicon-bonded alkenyl groups per molecule. Component (A-2) can be suitably represented by the following average structural formula (2):
(R ₃ SiO _1/2 ) _g (R ₂ SiO _2/2 ) _h (2)
(In formula (2), R represents the same monovalent hydrocarbon group as R in general formula (1) of component (A-1) described above, i) unsubstituted aliphatic unsaturated bond or ii) a monovalent alkenyl group. g and h each represent a positive number; or more, or 200 or more, and at the same time within the range of 300 or less, 400 or less, or 500 or less.

(A-2) Among all the siloxane units constituting the component, R ₃ SiO _1/2 units are 0.1 or more, 0.5 or more, or 1.0 or more and at the same time 10.0 or less, 5 0.0 or less, or 3.0 or less, with R ₂ SiO _2/2 units accounting for the balance, i. and at the same time 99.9 or less, 99.5 or less, or 99.0 or less. Here, the g:h ratio in Equation 2 corresponds to these mol % ratios. The molar ratio of the R ₂ SiO _2/2 units and the R ₃ SiO _1/2 units can be determined by nuclear magnetic resonance (NMR).

(A-2) In the average structural formula (2) of component (A-2), the ratio of silicon-bonded alkenyl groups in all monovalent hydrocarbon groups R bonded to silicon atoms is 0.25 or more in terms of mol %; It may be 50 or more, or 1.00 or more and at the same time 4.00 or less, 3.00 or less, or 2.00. The amount of alkenyl groups can be quantified using a Fourier transform near-infrared spectrometer.

The viscosity of component (A-2) at 25°C is in the range of 10 to 10,000 mPa·s, but it may be 1.0 or more, or 5.0 or more at 25°C. It may be within the range of the following mPa·s values.

(A-2) Component has the above structure, so that the direct reading value of 1/4 penetration defined by JIS K 2220 after curing is within the range of 10 to 150, so-called flexible A gel-like organopolysiloxane cured product can be obtained. By having the above viscosity, the component (A-2) contributes to improving the handling workability and fluidity of the organopolysiloxane composition of the present invention and the strength of the resulting cured product.

The linear organopolysiloxane represented by the average structural formula (2) is exemplified by a polymer comprising dimethylsiloxane, furthermore, for example, a polymer comprising methyltrifluoropropylsiloxane, or a polymer comprising dimethylsiloxane and・Or, in addition to methyltrifluoropropylsiloxane, a copolymer containing methylvinylsiloxane and/or diphenylsiloxane/phenylmethylsiloxane in an arbitrary ratio, and both ends of these polymers are dimethylvinylsiloxy groups, methyl capped with a divinylsiloxy group or a trivinylsiloxy group, or one end capped with a trimethylsiloxy group and the other end capped with a dimethylvinylsiloxy group; both ends capped with a trimethylsiloxy group, a vinyl a copolymer containing methylsiloxane, dimethylpolysiloxane and/or methyltrifluoropropylpolysiloxane in an arbitrary ratio and optionally containing diphenylsiloxane or phenylmethylsiloxane; and the like.

Among the linear organopolysiloxanes exemplified above, those containing no phenyl group, so-called dimethylpolysiloxane, have the effect of improving the mechanical strength of the cured product obtained by curing the organopolysiloxane composition of the present invention. However, unlike the above component (A-1), it cannot impart cold resistance. On the other hand, copolymers containing phenyl groups (so-called phenyl group-containing organopolysiloxanes), such as dimethylsiloxane-diphenylsiloxane copolymers blocked with dimethylvinylsiloxy groups at both ends, contribute to cold resistance. Therefore, if cold resistance is not required, component (A-2) containing only dimethylpolysiloxane without adding component (A-1) may be used as component (A). In order to achieve compatibility, the component (A-1) may be used in combination, and/or the component (A-2) may contain a phenyl group-containing polysiloxane. At this time, cold resistance can be imparted to the obtained cured product by controlling the content of the phenyl group in the composition to the amount described below.

Regardless of (A-1) or (A-2), when a phenyl group-containing organopolysiloxane is used as part or all of component (A), the content of phenyl groups is the entire functional groups bonded to silicon atoms. 1 or more, or 3 or more, and at the same time, 10 or less, or 7 or less as mol %. If the phenyl group content exceeds 10 mol %, the hardness of the cured organopolysiloxane may increase due to the phenyl groups in the cured product, resulting in loss of flexibility. This is because it may be difficult to form a gel-like cured product having a low hardness required for stress relaxation properties. Also, if the phenyl group content is less than the lower limit of 1 mol %, it may not be possible to impart sufficient cold resistance to the cured organopolysiloxane having a dimethylpolysiloxane skeleton.

Regardless of the component (A-1) or component (A-2), the above-described so-called phenyl group-containing organopolysiloxane is used as a main component, and the above-described so-called dimethylpolysiloxane is added to the above-described so-called phenyl group-containing organopolysiloxane. It is possible to improve the mechanical strength of the cured organopolysiloxane. Also in this case, the content of phenyl groups in the curable organopolysiloxane composition is preferably within the range exemplified in the preceding paragraph. In particular, if the phenyl group content exceeds the above upper limit, mutual dissolution with the dimethylpolysiloxane used in combination becomes difficult, and the uniformity of the composition as a whole may be impaired.

Regarding the quantitative relationship between component (A-1) and component (A-2), as described above, each may be used alone or in combination. From the viewpoint of achieving both physical strength, it is preferable to use 2 to 150 parts by mass, or 2 to 100 parts by mass of the dimethylpolysiloxane-based component (A-2) with respect to 100 parts by mass of the component (A-1). By setting the ratio within this quantitative range, it is possible to improve the physical properties while improving the cold resistance of the obtained organopolysiloxane cured product, and further improve the handleability of the organopolysiloxane composition before curing. , and is advantageous in terms of cost.

Component (A-3), which is an optional component, is an alkenyl group-containing organopolysiloxane resin, and is an organopolysiloxane component having a resinous, ie, three-dimensional, branched structure. Component (A-3) contains an average of at least two alkenyl groups in the molecule, a siloxane unit represented by R ^r SiO _3/2 (wherein R ^r is a monovalent organic group) and SiO _4/ An organopolysiloxane resin in which the total molar amount of siloxane units selected from the siloxane units represented by ₂ is at least 20 mol % of all siloxane units. R ^r is the same monovalent organic group as R in general formula (1) of component (A-1), i.e. i) an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bond; or ii) a monovalent alkenyl group or a hydroxyl group.

The description of the alkenyl group in component (A-1) in this application applies to the alkenyl group in component (A-3). Such alkenyl groups are particularly exemplified by vinyl groups or hexenyl groups. Since the alkenyl group has hydrosilylation reactivity, it can be expected to be incorporated into the cross-linking reaction forming the organopolysiloxane cured product, thereby improving the mechanical strength of the resulting cured product.

Examples of silicon-bonded groups other than alkenyl groups in component (A-3) include hydroxyl groups and unsubstituted or substituted monovalent hydrocarbon groups containing no aliphatic unsaturated bonds. and the number of carbon atoms is any integer within the range of 1 or more and simultaneously 2 or less, 3 or less, 4 or less, 6 or less, or 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. Unsubstituted or substituted monovalent hydrocarbon groups free of aliphatic unsaturation are specifically alkyl groups; aryl groups; aralkyl groups; or some of the hydrogen atoms of these groups. Alternatively, groups in which all of them are substituted with halogen atoms such as chlorine, bromine and fluorine, and alkoxy groups substituted with hydroxyl groups are included. Among them, methyl group, ethyl group, phenyl group, benzyl group, and especially methyl group, phenyl group and 3,3,3-trifluoropropyl group are exemplified because they are easy to synthesize. From the viewpoint of mutual solubility with other components contained in the composition, it is preferably an alkyl group, particularly a methyl group.

When component (A-3) is added, the amount added is arbitrary. At the same time, it can be added in the range of 10 or less, 7.5 or less, or 5.0 or less. In addition to the above components (A-1) and (A-2), by adjusting the amount of component (A-3) within this range, the mechanical strength of the resulting cured organopolysiloxane is improved. Is possible. It can be said that the effect of improving the mechanical strength by adding the amount of component (A-3) can be significantly observed when the amount added is 0.10% by mass or more. On the other hand, if it exceeds 10% by mass, the viscosity of the organopolysiloxane composition at 25° C. may become too high, and the resulting cured product may become too hard, which is not practically preferable.

(B) an alkenyl group-free organopolysiloxane resin having a low content of low-molecular-weight molecular species. Component (B) is one of the main components of the present invention and is an alkenyl group-free organopolysiloxane resin. . Specifically, an organopoly called MQ resin composed of siloxane units (M units) represented by (R ¹ ₃ SiO _1/2 ) and siloxane units (Q units) represented by (SiO _4/2 ) It is a siloxane resin. In the present invention, component (B) has a low content of low-molecular-weight formation reaction by-products, as described later, and therefore has a mass reduction rate of 2.0% by mass or less when exposed at 200° C. for 1 hour. The present invention is characterized in that the content of low-molecular weight reaction by-products in this MQ resin is low.

The (B) component organopolysiloxane resin can be specifically represented by the following average structural formula (3):
(R ¹ ₃ SiO _1/2 ) _a (SiO _4/2 ) _b (R ² O _1/2 ) _c (3)
(Wherein, a, b, and c are 0.35 ≤ a ≤ 0.55, 0.45 ≤ b ≤ 0.65, 0 ≤ c ≤ 0.05, and a + b = 1)
In the average structural formula (3) above, each R ¹ is an independent monovalent hydrocarbon group containing no aliphatic unsaturation, and the number of carbon atoms thereof is 1 or more, and simultaneously 2 or less and 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 is particularly exemplified by a methyl group and a phenyl group. Here, 70 mol% or more of all R ¹ in one molecule are exemplified by an alkyl group having 1 to 10 carbon atoms, especially a methyl group, and furthermore, all R 1 in one molecule It is noteworthy from the viewpoint of industrial production and the technical effects of the invention that 88 mol % or more of R ¹ are alkyl groups having 1 to 10 carbon atoms, especially methyl groups.

In the above formula (3), R ² is a hydrogen atom or an alkyl group, and in the case of an alkyl group, the number of carbon atoms is 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 any integer in the range of 10 or less. Examples of alkyl groups for ^R2 include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups. The group R ² O _1/2 containing R ² corresponds to a hydroxyl group or an alkoxy group, the oxygen atom of which is bonded to the silicon atom of the siloxane unit.

In the above formula (3), a, b, and c are each a siloxane unit represented by R ¹³ SiO _1/2 which is an M unit, a siloxane unit represented by SiO _{4/2 which} is a Q unit, and R ² It shows the ratio of hydroxyl groups or alkoxy groups represented by O _1/2 .

In the above formula (3), a is a number within the range of 0.35 or more, 0.40 or more, or 0.45 or more and simultaneously 0.60 or less, or 0.55 or less. When a is at least the lower limit of the above range, it is possible to prevent the viscosity of the composition containing this component from increasing. On the other hand, if a is equal to or less than the upper limit of the above range, the cured organopolysiloxane obtained by curing the curable silicone composition of the present invention will not have excessively low mechanical strength (hardness, elongation, etc.).

In the above formula (3), b is a number within the range of 0.40 or more, or 0.45 or more, and simultaneously 0.7 or less, or 0.65 or less. When b is within the above numerical range, the viscosity of the composition containing this component does not become too high, and the cured product obtained by curing the composition can be excellent in mechanical strength.

In the above formula (3), c may be 0, but in any case, it is a number within the range of 0.0 or more and 0.05 or less or 0.03 or less. When c is at or below the upper limit of the range, compositions containing this component exhibit excellent thermosetting properties.

Since the component (B) is produced by an equilibrium reaction of raw materials that provide the Q units forming the resinous polymer portion and the terminal M units, the ratio of the M units to the Q units, that is, the numerical values of a and b The molecular weight of component (B) can be controlled, and within the ranges of a and b above, gel permeation chromatography (GPC) measurement (based on polystyrene standard substance) measured using toluene as a solvent is 2,000 to 25, It will be a numerical value in the range of 000.

The so-called MQ resin, which is the main molecular species of component (B), can be synthesized with a desired molecular weight and designed structure by a known method. It is characterized by having a mass reduction rate of 2.0% by mass or less when exposed for a long period of time. The mass loss under these conditions is due to the presence of low molecular weight components that volatilize under these conditions. In the process of producing component (B), volatile low-molecular-weight components appear as by-products when an organopolysiloxane resin composed of M units and Q units is polymerized. This volatile low molecular weight component is referred to herein as the " _M4Q structure". When the M ₄ Q structure is incorporated into the organopolysiloxane composition of the present invention, it has the effect of significantly lowering the hardness of the cured organopolysiloxane obtained by curing the organopolysiloxane composition. The hardness of the organopolysiloxane cured product changes remarkably, and the change is evident in the number of penetration, which represents hardness.

Although it is known that such M ₄ Q structures are reduced and eventually lost when an organopolysiloxane resin containing them is kept at a temperature of 200° C. or higher, this is an organopolysiloxane containing M ₄ Q structures. It means that when an organopolysiloxane cured product containing a resin as a part of its composition is aged at a temperature of 200° C. or higher, the M ₄ Q structure gradually volatilizes. Penetration of is significantly reduced, that is, the hardness of the cured product is increased. That is, when an MQ resin is produced by a known method, it contains a certain amount or more of the M ₄ Q structure. The properties become inferior, and in particular deteriorate with time. In addition, since the content of the M ₄ Q structure is usually different for each lot of MQ resin, the penetration of the cured product obtained by using such MQ resin in a curable organopolysiloxane composition varies from lot to lot. There is also the problem of quality stability, which changes from time to time. Therefore, the curable organopolysiloxane composition of the present invention is characterized in that it does not contain an M ₄ Q structure. It is necessary to remove the M ₄ Q structure before it cures into a cured product.

In order to prevent the curable organopolysiloxane composition of the present invention from containing the M ₄ Q structure, after the organopolysiloxane resin of component (B) is synthesized, it is added to the organopolysiloxane composition of the present invention. The M ₄ Q structure can be removed prior to assembling. As a method for this, in the production process of the organopolysiloxane resin, after obtaining the particulate organopolysiloxane resin which is the crude raw material obtained after the polymerization reaction, it is dried in an oven or the like, or biaxially A method of removing it together with the above-described organic solvent in a kneader can be used. More specifically, the organopolysiloxane resin containing the M ₄ Q structure is treated at a high temperature of about 200° C. for a certain period of time depending on the surface area of the resin until no further mass reduction is observed, thereby removing the 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., the mass decreases for about 1 hour and then becomes constant. . It is also possible to simultaneously remove the organic solvent and volatile components such as the M ₄ Q structure from the organopolysiloxane resin, which is the component (B), using a twin-screw kneader set at 200°C. At this time, if the temperature is set to about 200° C., a residence time of about 5 minutes in the twin-screw kneader is sufficient. Also, if the cured organopolysiloxane to be processed is in the form of granules and heated to this temperature while being stirred in an atmosphere, the volatile low-molecular-weight M ₄ Q structure can be removed in a few minutes because of its large surface area relative to its volume. can.

Such an organopolysiloxane resin is produced by a polymerization reaction in the presence of an organic solvent that is highly compatible with raw material monomers. However, the M ₄ Q structure is more compatible with the organopolysiloxane resin than with such organic solvents and is difficult to remove under dry conditions that simply remove the organic solvent. In addition, such an M ₄ Q structure is added to component (A), component (C), component (D), or optional component (E) constituting the curable organosiloxane composition of the present invention during the process of its production. Therefore, the curable organopolysiloxane composition of the present invention or its cured product and the prior art MQ resin containing M ₄ Q structure instead of the component (B) and its cured product are These compositions or cured products are heated at 150° C. in advance to volatilize the organic solvent and the like, and then heated at 200° C. and measured for mass reduction. Further, volatilized components can be identified by gas chromatography or the like. As described above, the M ₄ Q structure itself is more difficult to volatilize than a solvent or the like, so it cannot be removed by a general raw material preparation method _. It must be removed by a step within a specific process. In addition, since compounds having a higher molecular weight than the M ₄ Q structure, such as structures represented by M ₆ Q ₂ and MVi ₄ Q, do not volatilize at a _temperature of about 200° C., this step It can be said that it is specialized for removing structures.

Component (B) is exemplified in an amount of 10 to 80 parts by mass per 100 parts by mass of component (A). More specifically, an amount within a range such as 10 or more, 15 or more, 20 or more, 40 or more, or 50 or more and at the same time 60 or less, 70 or less, or 80 or less is exemplified. In particular, ranges of 10 to 80 parts by mass, 15 to 80 parts by mass, and 40 to 70 parts by mass are exemplified. When component (B) is used within the above range, the amount of M ₄ Q structure that can be incorporated into the composition of the present invention is 1.0 parts by mass or less, or 0.5 parts by mass or less. Needless to say, the closer to 0 parts by mass, the better. By analyzing the composition of the present invention with a chromatographic formula, the remaining amount can be quantified from the molecular weight peak of the M ₄ Q structure.

(C) Organohydrogenpolysiloxane Crosslinking Agent Component (C) is a crosslinking agent and is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms (also referred to as SiH groups) per molecule. The present invention, wherein the SiH groups of component (C) are crosslinkable by reacting with the carbon-carbon double bonds contained in component (A) and other components in the presence of a hydrosilylation reaction catalyst. of the organopolysiloxane composition.

Component (C) is a monovalent hydrogen organosiloxy unit represented by HR ³ ₂ SiO _1/2 (represented by ^MH unit; R ³ is independently a monovalent organic group), or HR ³ SiO _2/2 Any organohydrogenpolysiloxane having a divalent hydrogen organosiloxy unit (represented by a D ^H unit; R ³ is independently a monovalent organic group) represented by the following may be used. Its structure is not particularly limited and may be linear, branched, cyclic or resinous. Specific examples of the structure of the component (C) include the use of only straight-chain organohydrogenpolysiloxanes containing ^MH units, or a combination of straight-chain and branched-chain organohydrogenpolysiloxanes. However, when an organopolysiloxane cured product obtained by curing the curable organopolysiloxane composition of the present invention is used for applications that require heat resistance, if unreacted SiH components remain in the system, Since there is a concern that further cross-linking will proceed and the penetration will change, all SiH groups in the system have good reactivity and react quickly rather than the ^DH unit, which has low reactivity and does not react easily with all SiH groups. It is preferred to use organohydrogenpolysiloxanes containing M ^H units that are reactive to . The amount of silicon-bonded hydrogen atoms in component (C) can be measured with an infrared spectrometer.

Component (C) consists of (C-1) chain organohydrogenpolysiloxane alone, or (C-1) chain organohydrogenpolysiloxane and (C-2) branched organohydrogenpolysiloxane. A mixture may be used. Each component is described below.

The chain organohydrogenpolysiloxane of component (C-1) reacts with component (A) and acts as a cross-linking agent for the present composition. Such a chain organohydrogenpolysiloxane has two silicon-bonded hydrogen atoms (SiH groups) in one molecule and has a viscosity within the range of 2 to 10,000 mPa·s. Component (C-1) has little or no branched structure and most of its structure is chain-like, and may particularly have a linear structure, and SiH groups are positioned at both ends of the chain. is exemplified. Such a (C-1) component can be represented by the following average structural formula (4):
(HR ³ ₂ SiO _1/2 ) ₂ (R ³ ₂ SiO _2/2 ) _v (4)
In formula (4), R ³ represents the same group as i) monovalent hydrocarbon group having no aliphatic unsaturated carbon bond in component (B) described above, and from an industrial point of view, a methyl group or A phenyl group is exemplified. In the formula, v is a number of 1 or more, preferably 2+v is 500 or less. As a specific structure, the following average structural formula:
(H(Me) ₂ SiO _1/2 )(Me ₂ SiO _2/2 ) _v1 (SiO _1/2 (Me) ₂ H)
(In the formula, Me is a methyl group)
An unbranched dimethylpolysiloxane in which both ends of the molecular chain are blocked with dimethylhydrogensiloxy groups is exemplified. Here, v1 is a number that makes the viscosity at 25° C. within the range of 2.0 to 500 mPa·s, or within the range of 2.0 to 150 mPa·s. That is, v1 is an integer that is greater than or equal to 1 and less than or equal to 50, less than or equal to 100, or less than or equal to 200. The following chain organohydrogenpolysiloxanes are also exemplified. In the formula, Me and Ph represent a methyl group and a phenyl group, respectively, v2 is an integer of 1-100, and v3 is an integer of 1-50.
_HMe2SiO ( _{Ph2SiO ) v2SiMe2H}
HMePhSiO( _Ph2SiO ) _v2SiMePhH
HMePhSiO( _Ph2SiO ) _v2 (MePhSiO) _v3 SiMePhH
HMePhSiO( _Ph2SiO ) _v2 ( _Me2SiO ) _v3 SiMePhH

(C-1) The content of chain organohydrogenpolysiloxane in the organopolysiloxane composition is the number of silicon-bonded hydrogen atoms exceeding 0 per alkenyl group of component (A), or The number is 0.1 or more, and at the same time the number is 1.5 or less, or the amount within the range of 1.2 or less is exemplified.

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

The branched organohydrogenpolysiloxane of component (C-2) is used in combination with component (C-1) described above, and reacts with component (A) to act as a cross-linking agent for the present composition. do. Such a branched organohydrogenpolysiloxane contains siloxane units represented by R ⁴ SiO _3/2 or SiO _4/2 in a ratio of at least 20 mol % of all siloxane units in the molecule to have a branched structure. . If the amount of these branching units is less than the above lower limit, it may not be possible to effectively adjust the penetration of the organopolysiloxane cured product obtained.

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

Component (C-2) may be an organohydrogenpolysiloxane represented by the following average unit formula (5):
(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)
(wherein j, k, m, n and p are numbers that satisfy the following: 0.1 ≤ j ≤ 0.80, 0 ≤ k ≤ 0.5, 0 ≤ m ≤ 0.8, 0 ≤ n≦0.6, 0≦p≦0.05, provided that m+n≧0.2, and j+k+m+n=1)
wherein each R ⁴ is the same or different, a monovalent hydrocarbon group of 1 to 10 carbon atoms or a hydrogen atom having no aliphatic unsaturated carbon bonds, provided that in one molecule, at least 3 ^R4 is a hydrogen atom. Regarding the monovalent hydrocarbon group represented by R ⁴ other than a hydrogen atom, the number of carbon atoms is 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, or 6 or more or 7 It may be any integer within the range of 8 or less, 9 or less, or 10 or less. An unsubstituted or substituted monovalent hydrocarbon group free of aliphatic unsaturation is specifically an alkyl group; an aryl group; an aralkyl group; an alkyl group; an aryl group; an aralkyl group; Groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms such as chlorine, bromine and fluorine. Among them, a methyl group, an ethyl group, a phenyl group, a benzyl group, and from an industrial point of view, a methyl group or a phenyl group are particularly exemplified because synthesis is easy.

On the other hand, R ⁵ is a hydrogen atom or any integer within the range of 1 or more, 2 or less, 3 or less, 4 or less, 6 or less, or 6 or more or 7 or more, and simultaneously 8 or less, 9 or less, 10 or less. is an alkyl group having an integer number of carbon atoms within the range of . That is, R ⁵ O _1/2 represents a hydroxyl group or an alkoxy group. R ⁵ is particularly exemplified by a hydrogen atom, a methyl group or an ethyl group, and thus OR ⁵ is exemplified by a hydroxyl group, a methoxy group or an ethoxy group.

where j, k, m, n, and p are numbers that satisfy: 0.1≤j≤0.80, 0≤k≤0.5, 0≤m≤0.8, 0≤ n≦0.6, 0≦p≦0.05, provided that m+n≧0.2, and j+k+m+n=1, where k=0 is particularly exemplified. When the present composition is used for heat-resistant applications, the resinous organohydrogenpolysiloxane, which is an example of component (C-2), is specifically M ^H MT resin, M ^H MTTT ^H resin, M ^H MTQ resin. , M ^H MQ resin, M ^H MTT ^HQ , and M ^HQ resin. Here, these resins are indicated by the siloxane units they contain, for example, M ^H MTQ resins are resins containing M units, M ^H units, T units, and Q units in arbitrary proportions. The M unit, M ^H unit, T unit, and Q unit are as described above, and the T ^H unit represents HSiO _3/2 . In particular, the (C-2) component is
(H( _CH3 ) _{2SiO1 /2} ) _j1 (SiO4 _/2 ) _n1
It may be an M ^HQ resin represented by Here, j1+n1=1, 0.1≦j1≦0.80 and 0.20≦n1≦0.90 are exemplified.

The content of component (C-2) is exemplified by such an amount that the number of SiH groups is 0.05 to 0.8 per alkenyl group of component (A). More specifically, the amount in the range of 0.05 or more, or 0.1 or more and simultaneously 0.8 or less, or 0.75 or less is particularly exemplified. By controlling the content of the component (C-2) in the organopolysiloxane composition within this range, the hardness of the cured organopolysiloxane composition can be effectively controlled without excessively lowering the penetration. is possible. If the number of SiH groups contained in component (C-2) is less than the above lower limit with respect to one alkenyl group in component (A), it is difficult to control the penetration of the organopolysiloxane cured product due to this component. Become.

Component (C-2) has a viscosity at 25°C of 2.0 to 10,000 mPa s, preferably 2.0 to 5000 mPa s, more preferably 2.0 to 5,000 mPa s. It is within the range of 1000 mPa·s. Addition of component (C-2) having such a viscosity improves the handling workability and fluidity of the composition, and the strength of the resulting cured product.

Component (C-2) adjusts the penetration of the obtained organopolysiloxane cured product and improves crack resistance (especially cracks and breakage due to internal stress caused by temperature differences inside the member). have the effect of 1.0 alkenyl groups contained in the entire composition from the standpoint of physical properties including heat/cold resistance and crack resistance of the cured organopolysiloxane obtained by curing the organopolysiloxane composition according to the present invention. On the other hand, the total number of hydrogen atoms bonded to silicon atoms in components (C-1) and (C-2) is 0.7 or more, or 0.8 or more and simultaneously 1.2 or less , or a number in the range of 1.0 or less.

(D) Catalyst for hydrosilylation reaction The component (D) of the present invention promotes the hydrosilylation reaction between the silicon-bonded alkenyl groups in the component (A) and the silicon-bonded hydrogen atoms in the component (C). It is used as a catalyst for Examples of component (D) include platinum-based catalysts, rhodium-based catalysts, palladium-based catalysts, and non-platinum-based metal catalysts such as iron, ruthenium, and iron/cobalt. System catalysts are particularly exemplified. This platinum-based catalyst can be appropriately selected from known catalysts, and a typical example is a platinum-alkenylsiloxane complex. ,3-divinyl-1,1,3,3-tetramethyldisiloxane, which is preferably added in the form of an alkenylsiloxane solution of the complex. In addition, from the viewpoint of improving workability in handling and pot life of the composition, a particulate platinum-containing hydrosilylation reaction catalyst dispersed or encapsulated in a thermoplastic resin may be used. These hydrosilylation reaction catalysts may be used singly or in combination of two or more.

In the case of a particulate platinum-containing hydrosilylation reaction catalyst dispersed or encapsulated in a thermoplastic resin, the platinum-based addition reaction catalyst, which is the component (D), is dispersed in a thermoplastic resin such as a silicone resin, a polycarbonate resin, or an acrylic resin. It may be a thermoplastic resin fine particle containing a platinum-containing hydrosilylation reaction catalyst, which is a dispersed or encapsulated catalyst. In addition, part or all of component (D) may be a catalyst that exhibits activity in the composition only upon irradiation with high-energy rays, such as (methylcyclopentadienyl)trimethylplatinum (IV), bis(2, A high-energy beam-activated catalyst or a photo-activated catalyst typified by 4-pentanedionato)platinum (II) may also be used.

The amount of component (D) may be an effective amount, and can be appropriately increased or decreased depending on the desired curing speed. For example, in the case of a platinum-based catalyst, the amount of platinum metal is usually It is in the range of 0.1 to 1,000 ppm, preferably 1 to 300 ppm. Even if the compounding amount exceeds the upper limit of the above range, there is no superiority in terms of curing speed, and it is economically disadvantageous in terms of the price (cost) of platinum.

(E) The reaction product of (e1) an alkali metal silanolate and (e2) at least one cerium salt selected from cerium chloride or cerium carboxylates. It can be used when an organopolysiloxane composition containing an organopolysiloxane composition and/or a cured product thereof is used in applications requiring higher heat resistance. This reaction product, which is component (E), is described, for example, in JP-A-49-83744 and JP-A-60-240761 together with its production method. and their reactions are summarized below.

(e1) alkali metal silanolate is, for example, a reaction product obtained by ring-opening reaction of (e1-1) one or more cyclic organopolysiloxanes with (e1-2) alkali metal hydroxide, (e1 -3) It can be obtained by further reacting an organopolysiloxane having a viscosity of 10 to 10,000 mPa·s at 25°C.

式（６）中、Ｒは、上述した（Ａ）成分の一般式（１）におけるＲと同様な一価炭化水素基を表し、ｓおよびｔは、それぞれ０～８の整数であり、但し、３≦ｓ＋ｔ≦８である。（ｅ１-１）環状オルガノポリシロキサンとしては、具体的にはヘキサメチルシクロトリシロキサン（Ｄ３）、オクタメチルシクロテトラシロキサン（Ｄ４）、デカメチルシクロペンタシロキサン（Ｄ５）、ドデカメチルシクロヘキサシロキサン（Ｄ６）、の他、これらのメチル基の一部がその他の炭化水素基、水素基、または（メタ）アクリロキシ基、カルボキシル基、ビニル基、アミノプロピル基などの反応性の基に置換されたものでもよく、また、これらの各種オルガノポリシロキサンの混合物であってもよい。 Although the cyclic organopolysiloxane of component (e1-1) is not particularly limited, examples thereof include cyclic organopolysiloxanes having the following general formula (6).

In formula (6), R represents the same monovalent hydrocarbon group as R in general formula (1) of component (A) described above, and s and t are each an integer of 0 to 8, provided that 3≤s+t≤8. Specific examples of (e1-1) cyclic organopolysiloxanes include hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6 ), and some of these methyl groups are substituted with other hydrocarbon groups, hydrogen groups, or reactive groups such as (meth)acryloxy groups, carboxyl groups, vinyl groups, aminopropyl groups, etc. It may also be a mixture of these various organopolysiloxanes.

Alkali metal hydroxides as the component (e1-2) are not particularly limited, but examples thereof include sodium hydroxide and potassium hydroxide. The amount of such component (e1-2) is generally 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of component (e1-1), but is not limited thereto, depending on the reaction situation. You can adjust.

The organopolysiloxane of component (e1-3) may be any conventionally known linear organopolysiloxane having a viscosity at 25° C. within the range of 10 to 10,000 mPa·s, as long as it remains liquid at room temperature. It may contain some branches. In addition, the silicon atom of the siloxane unit may be an unsubstituted or substituted monovalent hydrocarbon group (a monovalent alkenyl group may be used) similar to those exemplified as R in the general formula (1) of component (A). ) is what joins. The molecular chain ends of this organopolysiloxane are trialkylsiloxy groups such as trimethylsiloxy groups, alkenyldialkylsiloxy groups such as vinyldimethylsiloxy groups, dialkenylalkylsiloxy groups such as divinylmethylsiloxy groups, trivinylsiloxy groups, and the like. and those blocked with a triorganosiloxy group such as a trialkenylsiloxy group of , a hydroxyl group, an alkoxy group, or the like.

The organopolysiloxane of component (e1-3) has a viscosity at 25° C. of 10 mPa·s or more, or 50 mPa·s or more, and at the same time, a viscosity of 1,000 mPa·s or 10,000 mPa·s. Within range. If the viscosity of the component (e1-3) is 10 mPa·s or less, there is a problem that the amount of evaporation at high temperatures tends to increase, resulting in a large change in mass. The amount of component (e1-3) is not particularly limited, but is generally 0.1 to 10 parts by mass per 100 parts by mass of component (e1-1).

The reaction of components (e1-1), (e1-2), and (e1-3) to obtain component (e1) is known from JP-A-60-240761 and the like, and (e1-1 ) to the component (e1-2) at room temperature to open the ring of the component (e1-1), then the component (e1-3) is added thereto and reacted under a nitrogen stream at, for example, 115° C. for 2 hours. be.

The (e2) component cerium salt is a chloride or carboxylate of cerium or a mixture of rare earth elements containing cerium as a main component. That is, a chloride represented by M ¹ Cly and a carboxylate represented by (R ⁴ COO) y M ¹ (wherein R ⁴ is the same or different monovalent hydrocarbon group, M ¹ is cerium or cerium as a main component) and y is 1 to 3) depending on the valence of ^M1 . Examples of carboxylic acids include 2-ethylhexanoic acid, naphthenic acid, oleic acid, lauric acid, and stearic acid. From the standpoint of ease of handling, the chloride or carboxylate of ^M1 is preferably used as a lower alcohol or organic solvent solution. The lower alcohol is methanol or ethanol, and the organic solvent is , Stoddard solvent (mineral spirit), ligroin, petroleum solvents such as petroleum ether, and aromatic solvents such as toluene and xylene.

The amount of component (e2) is such that the amount of ^M1 is 0.05 or more, or 0.1 or more parts by mass, and at the same time 5 parts by mass or less, or 3 parts by mass, per 100 parts by mass of the total amount of component (e1). The amount is exemplified as 1 part or less, but it is not limited to this, and may be adjusted depending on the reaction situation.

The amount of component (E) may be 0.20 or more, or 0.3 or more as parts by mass per 100 parts by mass of component (A), and at the same time, 10.0 or less, 5.0 or less, or 0.5 or less. It is added in parts by mass within a certain range, more specifically, in small amounts such as 0.2 parts by mass, 0.3 parts by mass, and 0.4 parts by mass. Furthermore, the amount of component (E) added is such that the M ¹ content in component (E) is 0.005 or more, or 0.01 or more, and at the same time 0.15 or 0.1 An amount within the range of % by mass is exemplified. Most of this M ¹ exists as a silanolate, which is a silicon-containing compound having at least one unit in which the M ¹ atom is bonded to a silicon atom via an oxygen atom, but other forms (E) Weigh as contained in the ingredients. Setting the amount of component (E) within this range is advantageous in terms of the heat resistance of the resulting organopolysiloxane composition. If the amount of component (E) added is less than 0.20 parts by mass, the effect of improving heat resistance at high temperatures cannot be seen, and if it exceeds 10 parts by mass, the transparency of the cured organopolysiloxane is reduced. In addition, the cost of the organopolysiloxane composition increases, which is economically disadvantageous.

Component (E) can be obtained, for example, by dissolving component (e1) obtained as described above in an appropriate solvent (e.g., isopropanol), and dropping the solution of component (e2) at room temperature to obtain (e1) and (e2). After the components are mixed, they are heat-treated at a temperature of 150° C. or higher, and a solid reactant can be obtained by filtering, recovering, and removing the solvent under reduced pressure and mild heating. The heating temperature in the heat treatment can be 150° C. or higher, 200° C. or higher, or 250° C. or higher, and at the same time, the heat treatment can be performed within a temperature 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, and when it exceeds 310°C, there is a problem that the thermal decomposition rate of component (e1-3) increases, for example.

The high-strength organosiloxane cured product of the present invention further contains component (E) so that it maintains flexibility even under high temperature conditions for a long period of time, and continuously exhibits the desirable characteristics of low elastic modulus and low stress. In other words, when the component (E) is added to the organopolysiloxane composition of the present invention, it has excellent heat resistance and transparency at high temperatures exceeding 200°C, and even after long-term use at high temperatures, it has a low elastic modulus, low stress and high heat resistance. It is possible to form an organopolysiloxane cured product that maintains transparency and has crack resistance.

Other Optional Components In addition to the above components (A) to (D) and the optional component (E), the composition of the present invention may contain, as long as the object of the present invention is not impaired, for example, a reaction inhibitor, Optional ingredients such as inorganic fillers, organopolysiloxanes that do not contain silicon-bonded hydrogen atoms and silicon-bonded alkenyl groups, adhesion imparting agents, heat resistance imparting agents, flame retardant agents, thixotropic agents, pigments, dyes, etc. May be mixed.

The tackifier is a component that improves the adhesiveness of organopolysiloxane to substrates and the like, and can be appropriately selected from those generally known to those skilled in the art. It is preferable to select and use a substance or a quantitative range in which the type and amount of the tackifier do not reduce the transparency of the cured organopolysiloxane or cause curing inhibition. , When the organopolysiloxane cured product of the present invention is evaluated by the method described in the Examples section of the present application, it is substantially transparent, and the direct reading value of 1/4 penetration specified in JIS K2220 is 200 or less. Any range can be used as long as it provides a range of organopolysiloxane compositions. To be added to the organopolysiloxane composition of the present invention, titanium compounds such as tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra(2-ethylhexyl) titanate, titanium ethylacetonate, titanium acetylacetonate, etc., JP-A-2002. The general formula (R ^a O) _z SiR ^b _(4-z) disclosed in JP-A-322364 (where R ^a represents an alkyl or alkoxyalkyl group and R ^b is an unsubstituted or substituted monovalent and z is a silane represented by 3 or 4), a partial hydrolysis condensate thereof, or a combination thereof, particularly methyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, Silane coupling agents such as methoxysilane are exemplified. Here, the content of the adhesion imparting agent is not limited and can be appropriately designed, but is generally within the range of 0.001 to 5% by mass based on the entire composition.

The reaction inhibitor is a component for inhibiting the hydrosilylation reaction of the organopolysiloxane composition, and can be appropriately selected from those generally known to those skilled in the art. Reaction inhibitors such as carboxylic acid ester-based and phosphite-based inhibitors are included. The amount of the reaction inhibitor added is generally 0.001 to 5% by mass of the total organopolysiloxane composition. In particular, for the purpose of improving the handling workability of the organopolysiloxane composition of the present invention, ethynylcyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, acetylenic alcohol compounds such as 3-phenyl-1-butyn-3-ol; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexene-1-yne; cyclotetrasiloxane such as 3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; Alkenyl siloxane; triazole compounds such as benzotriazole, etc. can be used without particular limitation.

Inorganic fillers can be added to further increase the mechanical strength, and the type thereof is not particularly limited. A filler is generally not blended, and when it is blended, the cured product can be made transparent if the amount is 20% by mass or less, particularly 10% by mass or less. In some cases, the use of nanoparticles can maintain transparency. When transparency is not a concern, for example, fumed silica, crystalline silica, precipitated silica, hollow filler, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, Inorganic fillers such as calcium carbonate, zinc carbonate, layered mica, carbon black, diatomaceous earth, and glass fibers; Examples include fillers whose surface has been treated with a compound to make the surface hydrophobic. In addition, silicone rubber powder, silicone resin powder, etc. may be blended.

[Preparation of organopolysiloxane composition]
The organopolysiloxane composition of the present invention is prepared by mixing the above components (A) to (D) (including optional components when component (E) and other optional components are blended) in a conventional manner. It can be prepared by At that time, the components to be mixed may be divided into two or more parts if necessary and mixed, for example, part of (A) component and (B), (C) and optional components and a part consisting of the rest of the component (A) and the component (D). In particular, any one of the parts preferably contains the reaction inhibitor as an optional component.

The method of mixing each component of the silicone composition is not particularly limited and may be conventionally known methods, but usually a uniform mixture can be obtained by simple stirring. Moreover, when a solid component such as an inorganic filler is included as an optional component, mixing using a mixing device is more preferable. Such a mixing apparatus is not particularly limited, and examples thereof include a single-screw or twin-screw continuous mixer, two-roll mixer, Ross mixer, Hobart mixer, dental mixer, planetary mixer, kneader mixer, Henschel mixer, and the like.

The organopolysiloxane composition thus obtained can be suitably used as a sealant for electronic parts or a laminating agent for displays. In particular, by using an organopolysiloxane composition containing the component (E) as a sealing agent for semiconductor chips or a bonding agent for displays, the composition is cured in a harsh environment where excellent heat resistance is required. It can effectively protect the semiconductor chip or display without causing cracks due to heat sources or local heating even under low temperatures.

[Curing of Organopolysiloxane Composition]
The organopolysiloxane composition of the present invention can be cured by a hydrosilylation reaction at room temperature or at a temperature suitable for the intended use to form a gel. An organopolysiloxane cured product having a hardness within the measurable range is obtained. The temperature conditions for curing are not particularly limited, but are usually within the range of 60°C to 150°C for practical use. The organopolysiloxane cured product thus prepared is also a uniform product of the present invention.

[Organopolysiloxane cured product]
The organopolysiloxane cured product of the present invention is excellent in mechanical strength and adhesive properties, and therefore can be suitably used as a laminating agent for displays, which are becoming larger in area and have a wider temperature range for reliability. In addition, by using the component (E) in combination, excellent heat resistance and transparency at high temperatures exceeding 200°C can be maintained, and low elastic modulus, low stress and high transparency can be maintained even after long-term use at high temperatures. And, as typified by placing a high-temperature heat source only on one side (for example, the bottom) of the cured organopolysiloxane, it is left for a long time in a state where only one direction of the cured organopolysiloxane is exposed to high temperatures. However, the cured product of organopolysiloxane is less prone to defects such as cracks due to the temperature difference and internal stress inside the member. When it contains the component (E), and when it is used to protect electronic components such as semiconductor chips, SiC semiconductor chips, ICs, hybrid ICs, and power devices, it maintains transparency even at high temperatures and has excellent heat resistance. Not only is it expected to improve long-term durability, but it also resists deterioration even at low temperatures, so it has the advantage of being able to provide highly reliable and highly durable electronic components even under harsh operating conditions with large temperature differences. . In particular, electronic parts comprising cured organopolysiloxane as a sealant or the like have high reliability and high durability even under severe operating conditions with large temperature differences. Note that the semiconductor chip includes a light-emitting semiconductor element such as an LED.

(1/4 consistency)
The organopolysiloxane cured product of the present invention has a direct reading value of 1/4 penetration defined by JIS K2220 (reading unit is 1/10 mm) of 10 or more, 20 or more, or 30 or more and 150 or less or 120 at the same time. less than or equal to 100 or less. An organopolysiloxane cured product exhibiting a direct reading value of 1/4 penetration defined by JIS K2220 in such a range has characteristics of an organopolysiloxane cured product such as a low elastic modulus and a low stress. If the penetration is less than 10, it is difficult to exhibit the features of the cured organopolysiloxane such as low elastic modulus and low stress. difficult to hold and flow. In addition, the "direct reading of 1/4 consistency" means that the sample surface This is the value obtained by dropping a 1/4 cone from the top and reading the depth to which this cone entered.

(transparency)
The organopolysiloxane cured product of the present invention is preferably transparent, especially when used for display applications. On the other hand, when used as a sealant for power devices and the like, it may be colored, but it is industrially preferable to be substantially transparent. The term “substantially transparent” means that the pre-degassed silicone gel composition is gently poured into an aluminum cup to a thickness of 10 mm, visually confirms that there are no air bubbles, and then the temperature rises from 80°C to 150°C. It means that an organopolysiloxane cured product having a thickness of 10 mm obtained by heating at an arbitrary temperature is transparent to the extent that the bottom surface of the aluminum cup can be visually observed when viewed from above. Having such transparency, the organopolysiloxane cured product is useful as a sealing agent for semiconductors such as power devices.

Since the cured organopolysiloxane product of the present invention imparts excellent durability to electronic components comprising the cured product, one aspect of the present invention is a method for protecting electronic components. 2) The composition is cured by heating, and the resulting cured product is placed on the spot. Depending on the heat resistance of the electronic components and the substrate on which they are mounted, the heating can be carried out within the range of approximately 80° C. to 150° C. until the composition loses its fluidity.

Further, one aspect of the present invention is an electronic component comprising the cured organopolysiloxane described above, and examples thereof include automotive electronic components, consumer electronic components, and display members. The electronic component may be an optoelectronic component, exemplified by a light-emitting semiconductor device such as an LED, and a general luminaire comprising this is also part of the present invention. In particular, an electronic component comprising a cured organopolysiloxane containing component (E) may be exposed to severe temperature changes such as in outer space. Further, an electronic component including a power semiconductor, particularly a SiC semiconductor, exposed to a high temperature of 200° C. or higher and a cooling cycle, and a device mounted thereon are also an aspect of the present invention. Power devices with power semiconductors include motor controls, transport motor controls, power generation systems, and space transportation systems.

EXAMPLES The organopolysiloxane composition and silicone cured product of the present invention will be described in detail below with reference to examples. It should be noted that the present invention is not limited to the description of the following examples as long as the gist of the present invention is not exceeded. Viscosities in the examples are values at 25°C.

[Generation of (E) component]
The (E) component was produced|generated by the following method. A mixture of hexamethylcyclotrisiloxane and octamethylcyclotetrasiloxane was subjected to a ring-opening reaction with potassium hydroxide to prepare a potassium silanolate compound. 100 g of this potassium silanolate compound was dissolved in 150 g of isopropanol, and a mixture of 2.5 g of anhydrous cerium chloride, 50 g of ethanol, and 50 g of methanol was added dropwise to react with stirring. After filtering this reaction mixture, the filtrate was heated to 40 to 50° C. under reduced pressure to distill off ethanol and methanol. Next, this was filtered again to prepare a pale yellow liquid reaction product. The content of cerium in this reaction product was 1.4% by mass.

[Evaluation of Organopolysiloxane Composition and Organopolysiloxane Cured Product]
The transparency, 1/4 consistency, heat resistance and crack resistance of the cured organopolysiloxane of the present invention were measured as follows.

(Preparation of organopolysiloxane cured product)
After gently pouring the organopolysiloxane composition into a 50 ml glass beaker until it reached a height of 3 cm from the bottom of the beaker, the composition was heated at 80° C. for 1 hour to prepare an organopolysiloxane cured product.

(Measurement of 1/4 penetration)
Similar to the penetration test with a 1/4 cone specified in JIS K2220, a 1/4 cone is dropped from the surface of the target organopolysiloxane cured product using a JIS K2220 1/4 consistency meter. , the depth to which this cone penetrated was read (the reading unit is 1/10 mm), and this value was recorded as a "direct reading".

(Heat resistance of cured organopolysiloxane)
The organopolysiloxane cured product cured by the above method was placed in an oven at 225°C, removed after 1000 hours, left at room temperature, and naturally cooled to 25°C. After that, the 1/4 consistency of this cured organopolysiloxane was measured and the direct reading value (reading unit: 1/10 mm) was recorded as 1/4 consistency.

(Crack resistance of cured organopolysiloxane)
After the cured organopolysiloxane product cured by the above method was placed on a hot plate heated to 225° C., the appearance of the organopolysiloxane was observed through a beaker for 1000 hours. When the occurrence of cracks was visually confirmed within 1000 hours, the time was recorded.

(Mechanical strength and adhesive strength of cured organopolysiloxane)
Using two aluminum plates of 25 mm×75 mm×1 mm, adhesive strength and mechanical strength were measured by the method specified in JIS K6850/1999. When the test ends with cohesive failure of the organopolysiloxane, the adhesion strength directly indicates the mechanical strength of the organopolysiloxane.

[Examples 1 to 8 and Comparative Examples 1 to 13]
The components shown in Tables 1, 2, 3 and 4 below were uniformly mixed in the compositions (parts by mass) shown in Tables 5 and 6 to prepare 21 types of organopolysiloxane compositions. These organopolysiloxane compositions were cured by the methods described in the respective evaluation methods above, and the 1/4 consistency, heat resistance, and crack resistance of the resulting cured organopolysiloxane compositions were evaluated. These are summarized in Tables 5 and 6 below. In addition, SiH/Vi in the table is (C-1) component and (C-2) component per 1 mol of vinyl groups contained in the total of (A-1) component, (A-2) component and (D) component. It shows the number of moles of silicon-bonded hydrogen atoms in the total. In addition, the platinum metal content of component (D) is shown in ppm in the composition.

★ 揮発量とはこのオルガノポリシロキサン樹脂約１gを直径５０ｍｍのアルミカップに計量して２００℃にて１時間放置したときの質量減少を％で表したもの。この数値は前述の通りＢ成分中に残るＭ_４Ｑ構造体の量と一致する。

* The volatilization amount is the weight reduction in % when about 1 g of this organopolysiloxane resin is weighed into an aluminum cup with a diameter of 50 mm and left at 200°C for 1 hour. This number agrees with the amount of M ₄ Q structures remaining in the B component, as described above.

*ＳｉＨ含有量=ケイ素原子結合水素原子の含有量

*SiH content = content of silicon-bonded hydrogen atoms

[Summary]
As shown in Table 5, Examples 1-5 demonstrate the performance of the basic organopolysiloxane compositions of the present invention. The cured products of these compositions contain the component (B), which is characteristic of the present invention, and exhibit higher adhesive strength and mechanical strength than Comparative Examples 1 and 2, which do not contain a sufficient amount of the component (B). Therefore, it was found that a composition containing component (B) could provide a tougher organopolysiloxane composition. Also, from Comparative Examples 3 and 4, it is possible to confirm the contribution of the component (C) within the scope of the present invention to the performance. Furthermore, Comparative Examples 5 and 6 had the same composition as Example 4 except that the component (B) contained a volatile component, but the strength was relatively inferior, the 1/4 consistency was high, and there was variation. Therefore, the basic organopolysiloxane cured product of the present invention stably exhibits high strength and can be suitably used in applications requiring strength. Table 6 shows Examples 6 to 8 and Comparative Examples in which an optional component (E) was further added. The heat resistance of the cured organopolysiloxane obtained from these compositions and the crack resistance when heated from one direction at 225° C. for a long period of time are generally good. The consistency did not change significantly, but the strength was significantly inferior in the case where the component (B) was not included as in Comparative Examples 7 to 11. In addition, the compositions of Comparative Examples 12 and 13 had the same compositions as those of Examples 7 and 8, respectively, except that the component (B) contained a volatile component. Since the component (B) does not have a mass reduction rate of 2.0% by mass or less upon exposure, the crack resistance is remarkably inferior.

（＊１）Ｂ成分に含まれる２００℃にて揮発する成分、つまりＭ_４Ｑ構造体の量から算出した。
（＊２）接着試験の破壊モードは全て凝集破壊となったので、接着強度＝オルガノポリシロキサン硬化物の機械的強度となる。 Table 5 Performance of basic composition

(*1) Calculated from the amount of the component that volatilizes at 200°C contained in the B component, that is, the amount of the M ₄ Q structure.
(*2) Since the failure mode of the adhesion test was all cohesive failure, the adhesion strength = the mechanical strength of the cured organopolysiloxane.

（＊１）Ｂ成分に含まれる２００℃にて揮発する成分、つまりＭ_４Ｑ構造体の量から算出した。
（＊２）接着試験の破壊モードは全て凝集破壊となったので、接着強度＝オルガノポリシロキサン硬化物の機械的強度となる。 Table 6 Effect of component (B) in heat-resistant organopolysiloxane composition containing component (E)

(*1) Calculated from the amount of the component that volatilizes at 200°C contained in the B component, that is, the amount of the M ₄ Q structure.
(*2) Since the failure mode of the adhesion test was all cohesive failure, the adhesion strength = the mechanical strength of the cured organopolysiloxane.

Since the organopolysiloxane cured product obtained from the organopolysiloxane composition of the present invention has strength and transparency, it can be used as a sealant for various semiconductor elements, a protective material, an optical element sealant, a laminated member for displays, and general lighting. Optical or optoelectronic components, lenses (including secondary optical lens materials provided on the outside of LED packages), light diffusion components, white reflector components, wavelength conversion components, optical waveguides and guides used in equipment, etc. A light guide and the like are exemplified. When used as an optical member or optoelectronic member, various functional fillers (fluorescent, light diffusing, translucent, coloring, reinforcing fillers, etc.) are added to the organopolysiloxane composition of the present invention. Also good. The organopolysiloxane composition of the present invention can be used in the same manner as conventional organopolysiloxane compositions having similar optical properties, and due to its high strength, it is more excellent in protecting devices and parts containing it than conventional compositions. Increase reliability.

Furthermore, the cured organopolysiloxane obtained from the organopolysiloxane composition of the present invention containing the component (E) has heat resistance of 200° C. or higher, which is required for SiC semiconductor chips, and is subjected to high temperatures only in one direction. Since it is difficult to crack even when it is subjected to heat, it has a high degree of freedom in terms of circuit design, including thermal management. The durability and reliability of power devices can be improved. Power devices that require such heat resistance and crack resistance include, for example, general-purpose inverter control, servo motor control, motor control for machine tools and elevators, motor control for electric vehicles, hybrid cars, and railway transport equipment, solar power Systems for generators such as light, wind power, and fuel cell power generation, space transportation systems used in space, and the like.

Claims (15)

(A) an organopolysiloxane having an average of at least two silicon-bonded alkenyl groups per molecule and a viscosity at 25° C. within the range of 10 to 10,000 mPa·s: 100 parts by mass;
(B) 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, the following formula:
( ^R13SiO1 _{/ 2} ) _a (SiO4 _/2 ) _b (R2O1 _/ ² ) _c
(wherein each R ¹ is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms and no aliphatic carbon-carbon double bonds; R ² is a hydrogen atom or 1 to 10 Alkyl groups having carbon atoms; a, b, and c are numbers satisfying 0.35 ≤ a ≤ 0.55, b = 1-a, 0 ≤ c ≤ 0.05) Organopolysiloxane resin: 10 to 80 parts by mass,
(C) Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule and having a viscosity at 25° C. within the range of 2 to 10,000 mPa·s: Silicon accounts for the entire composition an amount such that there are 0.5 to 2.0 silicon-bonded hydrogen atoms per atom-bonded alkenyl group;
(D) a catalyst for the hydrosilylation reaction: in an amount sufficient to react and cure (A) through (C), and optionally (E) (e1) an alkali metal silanolate and (e2) M ¹ Cl _y Chloride and carboxylate represented by (R ⁴ COO) _y M ¹ (wherein R ⁴ is the same or different monovalent hydrocarbon group, M ¹ is cerium or a mixture of rare earth elements containing cerium as the main component, y is at least one salt selected from 1 to 3) depending on the valence of M ¹ , the reaction product of: 0 to 10 parts by mass,
An organopolysiloxane composition containing 2. The organopolysiloxane composition of claim 1, wherein the content of the _M4Q structure is 1.0 parts by mass or less. Component (A) has (A-1) at least two silicon-bonded alkenyl groups in one molecule, and has a viscosity at 25° C. within the range of 10 to 10,000 mPa s. Branched organopolysiloxane represented by 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 which are alkenyl groups, and d, e, and f are 0.1 ≤ d ≤ 10.0, 80.0. ≤ e ≤ 99.8, 0.1 ≤ f ≤ 10.0, and a number that satisfies d + e + f = 1), and (A-2) having at least two alkenyl groups bonded to silicon atoms in one molecule, a linear organopolysiloxane having a viscosity at 25° C. in the range of 10 to 10,000 mPa·s;
3. The organopolysiloxane composition according to claim 1 or 2, which is any one or a mixture of 4. The organopolysiloxane according to claim 3, wherein 0.25 to 4.00 mol % of all monovalent hydrocarbon groups bonded to silicon atoms in component (A-1) are alkenyl groups. Composition. The component (C) is (C-1) a linear organohydrogenpolysiloxane having a viscosity at 25° C. within the range of 2 to 1,000 mPa·s and having two silicon-bonded hydrogen atoms per molecule. : an amount such that the number of silicon-bonded hydrogen atoms exceeds 0 and is 2.0 or less per silicon-bonded alkenyl group in the entire composition, and optionally (C-2) at 25 ° C. It has a viscosity within the range of 2 to 1,000 mPa·s, has 3 or more silicon-bonded hydrogen atoms in its molecule, and is R ⁴ SiO _3/2 (wherein R ⁴ is a monovalent carbonized Hydrogen groups) or branched organohydrogenpolysiloxanes containing at least 20 mol % of all siloxane units of siloxane units represented by SiO _4/2 : one silicon atom per silicon-bonded alkenyl group in the total composition The amount of hydrogen atoms bonded to 0.1 to 0.8,
The organopolysiloxane composition according to any one of claims 1 to 4, characterized in that it contains 3. The organopolysiloxane composition according to claim 1, wherein component (E) contains 0.5 to 5.0% by mass of M ¹ atoms. An electronic component sealant comprising the organopolysiloxane composition according to any one of claims 1 to 6. 8. The electronic component encapsulant of claim 7, which is substantially transparent. Organopolysiloxane obtained by curing the organopolysiloxane composition according to any one of claims 1 to 6, and having a direct reading value of 1/4 penetration defined by JIS K2220 in the range of 10 to 150 Cured siloxane. 10. The cured organopolysiloxane of claim 9, which is substantially transparent. 11. An electronic component comprising the electronic component sealant according to claim 7 or claim 8 or the organopolysiloxane cured product according to claim 9 or 10. 12. The electronic component according to claim 11, mounted on a power device. 12. The electronic component according to claim 11, wherein said electronic component is an optoelectronic component. 14. The electronic component according to claim 13, which is mounted in general lighting fixtures, display members, optical members or optoelectronic members. 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, A method of protecting a semiconductor chip.