Addition-curing silicone composition

Abstract

The present invention provides an addition-curing silicone composition that yields a cured product with excellent oil resistance. [Solution] The present invention relates to an addition-curing silicone composition comprising (A) a polyorganosiloxane having alkenyl groups bonded to silicon atoms; (B) a polyorganohydrogensiloxane having hydrogen atoms bonded to silicon atoms; (C) a platinum catalyst; and (D) a flake-like inorganic filler with an average particle diameter of 100 μm or less.

Description

[Technical Field]

[0001] The present invention relates to an addition-curing silicone composition. [Background technology]

[0002] Traditionally, oil-resistant gasket materials have been used to seal automotive oils such as engine oil, gear oil, and automatic transmission fluid in automobile engines. However, the oil resistance of gasket materials (cured products) can be reduced due to the effects of acidic additives such as metal phosphates and metal phosphites contained in automotive oils, which can result in deterioration of rubber properties and reduced adhesion. Therefore, metal oxides or carbonates are usually added to the compositions used as gasket materials to neutralize the acidic additives.

[0003] As a composition used for such gasket materials, Patent Document 1 discloses a room-temperature curable organopolysiloxane composition containing (A) a diorganopolysiloxane in which both ends of the molecular chain are sealed with hydroxyl groups and has a viscosity of 25 to 1,000,000 cSt at 25°C, (B) an organosilane and / or a partial hydrolysate thereof containing three or more hydrolyzable groups selected from the group consisting of ketoxime groups and alkenoxy groups in one molecule, and (C) a flaky inorganic powder with an average particle size of 50 μm or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-17773 [Overview of the project] [Problems that the invention aims to solve]

[0005] Room-temperature curable organopolysiloxane compositions, such as those described in Patent Document 1, require time to cure at room temperature, resulting in a problem of long cycle times during manufacturing. Therefore, there was a demand for addition-curing silicone compositions with short cycle times during manufacturing.

[0006] The present invention aims to provide an addition-curing type silicone composition that yields a cured product with excellent oil resistance. [Means for solving the problem]

[0007] The present invention relates to the following [1] to [6]. [1](A) Polyorganosiloxanes having two or more alkenyl groups bonded to silicon atoms in the molecule; (B) Polyorganohydrogensiloxanes containing three or more hydrogen atoms bonded to silicon atoms in the molecule; (C) Platinum catalyst; (D) Scale-like inorganic fillers with an average particle size of 100 μm or less An addition-curing silicone composition containing the above. [2] The addition-curing silicone composition according to [1], further comprising (E) an acid acceptor. [3](E) The addition-curing silicone composition according to [1] or [2], wherein the acid acceptor comprises one or more selected from the group consisting of zinc oxide, titanium oxide, iron oxide, and calcium carbonate. [4] The addition-curing silicone composition according to any one of the items [1] to [3], further comprising one or more selected from the group consisting of (F) other inorganic fillers (excluding components (D) and (E)), (G) adhesion promoters, and (H) reaction inhibitors. [5] Component (A) is, (A1) Both ends are R3SiO 1 / 2 The unit is sealed, and the intermediate unit is R 2 2SiO 2 / 2 The unit is a linear polyorganosiloxane, (A2)SiO 4 / 2 Units and R3SiO 1 / 2 Includes units, and R2SiO as any unit.2 / 2 units and / or RSiO 3 / 2 The addition-curable silicone composition according to any one of [1] to [4], comprising a branched polyorganosiloxane containing units. A cured product obtained by curing the addition-curable silicone composition according to any one of [1] to [5]. [Advantages of the Invention]

[0008] The present invention provides an addition-curable silicone composition that gives a cured product excellent in oil resistance. [Modes for Carrying Out the Invention]

[0009] [Definition of Terms] The structural units of siloxane compounds may be described by the following abbreviations (hereinafter, these structural units may be referred to as "M units", "D H units", etc.). M<� :(CH3)3SiO 1 / 2 M H :H(CH3)2SiO 1 / 2 M Vi :(CH2=CH)(CH3)2SiO 1 / 2 D :(CH3)2SiO 2 / 2 D H :H(CH3)SiO 2 / 2 D Vi :(CH2=CH)(CH3)SiO 2 / 2 Q:SiO 4 / 2

[0010] In the present specification, specific examples of groups are as follows. Examples of the monovalent hydrocarbon group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. Examples of the monovalent hydrocarbon group having no aliphatic unsaturated bond include the above monovalent hydrocarbon groups other than the alkenyl group. Alkenyl groups are linear or branched groups having 2 to 6 carbon atoms, and examples include vinyl groups, allyl groups, 3-butenyl groups, and 5-hexenyl groups. Alkyl groups are linear or branched groups having 1 to 18 carbon atoms, and examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, hexadecyl, and octadecyl groups. Cycloalkyl groups are monocyclic or polycyclic groups having 3 to 20 carbon atoms, such as cyclopentyl and cyclohexyl groups. Aryl groups are aromatic groups containing monocyclic or polycyclic groups with 6 to 20 carbon atoms, such as phenyl groups and naphthyl groups. An aralkyl group is an alkyl group substituted with an aryl group, such as a 2-phenylethyl group or a 2-phenylpropyl group. Alkylene groups are linear or branched groups having 1 to 18 carbon atoms, and examples include methylene groups, ethylene groups, trimethylene groups, 2-methylethylene groups, and tetramethylene groups. Alkenyl groups, alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, and alkylene groups may be substituted with halogens such as chlorine, fluorine, and bromine; or with cyano groups. Examples of halogen-substituted groups include chloromethyl, chlorophenyl, and 3,3,3-trifluoropropyl groups, while examples of cyano-substituted groups include 2-cyanoethyl groups.

[0011] In this specification, "(A) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule" is also referred to as "component (A)". The same applies to "(C) platinum catalyst", etc. In this specification, "room temperature" means a temperature between 5°C and 40°C, preferably between 10°C and 35°C, and particularly preferably between 23°C.

[0012] [Addition-curing silicone composition] The addition-curing silicone composition (hereinafter also simply referred to as "the composition") is as follows: (A) Polyorganosiloxanes containing two or more alkenyl groups bonded to silicon atoms in the molecule; (B) Polyorganohydrogensiloxanes containing three or more hydrogen atoms bonded to silicon atoms in the molecule; (C) Platinum catalyst; and (D) Scale-like inorganic fillers with an average particle size of 100 μm or less Includes.

[0013] The addition-curing silicone composition according to the present invention can be cured in a shorter time by heating than condensation-type polyorganosiloxane compositions, resulting in a shorter cycle time in the production of cured products. Therefore, the addition-curing silicone composition according to the present invention has the advantage of a shorter curing time compared to room-temperature curable organopolysiloxane compositions containing diorganopolysiloxanes in which both ends of the molecular chain are sealed with hydroxyl groups or hydrolyzable groups. However, since addition-curing polyorganosiloxane compositions require heating for curing, their use has been avoided in environments where room-temperature curable organopolysiloxane compositions are used. The addition-curing polyorganosiloxane composition has the advantage of being usable not only in environments near room temperature but also in heated environments, thus shortening the curing time.

[0014] <(A) Polyorganosiloxanes having two or more alkenyl groups bonded to silicon atoms in the molecule> (A) A polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in its molecule (hereinafter also referred to as "(A) alkenyl group-containing polyorganosiloxane") is a base polymer component in the composition. Component (A) is not particularly limited as long as it has an average of two or more alkenyl groups bonded to silicon atoms in one molecule and can form a network structure by addition reaction with the hydrosilyl group (Si-H group) of component (B). It is preferable that component (A) does not have any reactive organic functional groups other than the alkenyl groups bonded to silicon atoms, such as epoxy groups, silanol groups, or alkoxysilyl groups.

[0015] (A) Component is typically represented by general formula (I): (R 1 ) a (R 2 ) b SiO (4-a-b) / 2 (I) (In the formula, R 1 is an alkenyl group; R 2 It is a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond; a is an integer between 1 and 3; b is an integer between 0 and 2, where a + b is between 1 and 3. The molecule contains at least two alkenyl group-containing siloxane units, as shown by .

[0016] R 1 A vinyl group is preferred because it is easy to synthesize and does not impair the fluidity of the composition before curing or the heat resistance of the composition after curing. A is preferred because it is easy to synthesize. 2 A methyl group is preferred because it is easy to synthesize and has an excellent balance of properties such as mechanical strength and fluidity before curing.

[0017] (A) Examples of organic groups bonded to the silicon atoms of other siloxane units in component (A) include monovalent hydrocarbon groups that do not have aliphatic unsaturated bonds. The said organic group is R 2 For similar reasons, a methyl group is preferred.

[0018] R 1 It may be present at either the end or in the middle of the molecular chain of component (A), or both.

[0019] The siloxane skeleton of component (A) can be linear or branched. That is, component (A) can be (A1) a linear alkenyl group-containing polyorganosiloxane or (A2) a branched alkenyl group-containing polyorganosiloxane.

[0020] (A1) As a linear alkenyl group-containing polyorganosiloxane, both ends are R3SiO 1 / 2 The unit is sealed, and the intermediate unit is R 2 2SiO 2 / 2 A linear polyorganosiloxane is an example of a unit. Here, R is R 1 or R 2 However, in R, there are 2 or more per molecule. 1 (A1) Component R3SiO 1 / 2 The unit is R 1 R 2 2SiO 1 / 2 Unit, R 1 2R 2 SiO 1 / 2 Unit or R 1 3SiO 1 / 2 It is preferable that it be a unit, R 1 R 2 2SiO 1 / 2 It is particularly preferable that the units are M. In particular, component (A1) has M at both ends. vi A linear polyorganosiloxane that is occluded by units (dimethylvinylsiloxane units) and whose intermediate units consist only of D units (dimethylsiloxane units) is particularly preferred.

[0021] (A2) Branched alkenyl group-containing polyorganosiloxanes include SiO 4 / 2 Units and R3SiO 1 / 2 Includes units, and any unit R2SiO 2 / 2 Units and / or RSiO 3 / 2 Examples include branched polyorganosiloxanes containing units, where R is R 1 or R 2 However, in R, there are 2 or more per molecule. 1 Therefore, in the hardening reaction, at least 3 R molecules per molecule are present in R so that they act as crosslinking sites. 1 And the remainder is R 2 Preferably, the cured product of the composition has excellent mechanical strength, and R3SiO 1 / 2 Units and SiO 4 / 2The ratio of the units is preferably a resinous substance that is solid or viscous semi-solid at room temperature in the range of 1:0.8 to 1:3 as a molar ratio. The R3SiO unit in the (A2) component 1 / 2 unit is preferably R 1 R 2 2SiO 1 / 2 unit, R 1 2R 2 SiO 1 / 2 unit or R 1 3SiO 1 / 2 unit, and it is particularly preferably R 1 R 2 2SiO 1 / 2 unit. Also, the R2SiO unit is preferably R 2 / 2 R 1 R 2 SiO 2 / 2 unit or R 1 2SiO 2 / 2 unit, and it is particularly preferably R 1 R 2 SiO 2 / 2 unit. Further, R 1 is preferably present as R in the R3SiO unit or R2SiO unit.

[0022] (In the (A2) component, R 1 may be present as R in the R3SiO unit, or may be present as R in the R2SiO unit or the RSiO unit. From the viewpoint of obtaining fast curing at room temperature, part or all of the R3SiO units are R 1 / 2 R 2 / 2 R 3 / 2 2SiO 1 / 2 units, and / or part or all of the R2SiO units are R 1 R 2 R 1 / 2 SiO 2 / 2 units, which is preferable.

[0023] <Preferred embodiments of the (A) component> ​​​​​​​​​​The viscosity of component (A) is preferably 0.1 to 500 Pa·s, more preferably 0.5 to 300 Pa·s, and particularly preferably 1.0 to 200 Pa·s at 23°C. When the viscosity of (A) is within the above range, adhesion to various substrates can be efficiently enhanced, and the uncured composition exhibits good fluidity, resulting in excellent workability during casting and potting. Furthermore, when the viscosity of (A) is within the above range, the cured composition can exhibit excellent mechanical strength and appropriate elasticity and hardness. Here, if component (A) is a combination of two or more types, the viscosity of component (A) refers to the viscosity of the mixed alkenyl group-containing polyorganosiloxane.

[0024] In this specification, the viscosity of component (A) is the value measured at 23°C using a rotational viscometer, with the spindle number and rotation speed appropriately set in accordance with JIS K6249:2003.

[0025] Component (A) may be one type or a combination of two or more types. From the viewpoint of providing a cured product with better oil resistance, it is preferable that component (A) contains component (A2). Also, from the same viewpoint, it is more preferable that component (A) is a mixture of component (A1) and component (A2).

[0026] Component (A) has R at both ends (A1'). 1 R 2 2SiO 1 / 2 The unit is sealed, and the intermediate unit is R 2 2SiO 2 / 2 The unit is a linear polyorganosiloxane with a viscosity of 0.1 to 500 Pa·s at 23°C, as well as (A2')SiO 4 / 2 Units and R3SiO 1 / 2 It includes units and any unit R2SiO 2 / 2 Units and / or RSiO 3 / 2 Branched polyorganosiloxanes containing units (in the above formulas, R is R 1 or R 2 And R 1 is an alkenyl group, and R 2It is a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and has two or more R groups in the molecule. 1 It is particularly preferable that it be a mixture of (containing)

[0027] <(B) Polyorganohydrogensiloxane containing three or more hydrogen atoms bonded to silicon atoms in the molecule> (B) Polyorganohydrogensiloxanes having three or more hydrogen atoms bonded to silicon atoms in the molecule (hereinafter also referred to as "(B) polyorganohydrogensiloxane") have hydrosilyl groups contained in the molecule that are R of component (A). 1 It functions as a crosslinking agent for component (A) by undergoing an addition reaction with (B). Component (B) is not particularly limited as long as it has three or more hydrogen atoms bonded to the silicon atoms involved in the addition reaction in order to form a network in the cured product. It is preferable that component (B) does not have any reactive organic functional groups other than the hydrogen atoms bonded to the silicon atoms, such as epoxy groups, silanol groups, or alkoxysilyl groups. It is also preferable that component (B) does not have any divalent aromatic groups other than the hydrogen atoms bonded to the silicon atoms.

[0028] (B) Component is typically represented by general formula (II): (R 5 ) c H d SiO (4-c-d) / 2 (II) (In the formula, R 5 This represents a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond; c is an integer between 0 and 2; d is an integer between 1 and 3, where c + d is an integer between 1 and 3. It has three or more units represented by in its molecule.

[0029] R 5 A methyl group is preferred for d because it is easy to synthesize. Also, 1 is preferred for d because it is easy to synthesize.

[0030] Because it is easy to synthesize, component (B) preferably consists of three or more siloxane units. Furthermore, because it does not volatilize when heated to the curing temperature and has excellent fluidity, making it easy to mix with component (A), the number of siloxane units in component (B) is preferably 6 to 200, and particularly preferably 10 to 150.

[0031] The siloxane skeleton in component (B) may be linear, branched, or cyclic, with linear being preferred.

[0032] (B) Component (B1) has both ends independently, R 6 3SiO 1 / 2 The unit is closed, and the intermediate unit is R 6 2SiO 2 / 2 Linear polyorganohydrogensiloxanes consisting only of units, or (B2)R 6 3SiO 1 / 2 Units and SiO 4 / 2 Polyorganohydrogensiloxane consisting only of units (in each of the above formulas, R 6 Each of these is independently a monovalent hydrocarbon group that does not have a hydrogen atom or an aliphatic unsaturated bond, however, R 6 It is preferable that at least three hydrogen atoms are present on average per molecule. In the cases of (B1) and (B2), R 6 3SiO 1 / 2 The unit is HR. 7 2SiO 1 / 2 Units and R 7 3SiO 1 / 2 The units are listed, R 6 2SiO 2 / 2 The unit is HR. 7 SiO 2 / 2 Units and R 7 2SiO 2 / 2 Unit (In the above formulas, R 7 Examples include a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond. In the case of (B1), the hydrogen atom bonded to the silicon atom may be located at the terminal or in the intermediate unit, but it is preferable that it be located in the intermediate unit.

[0033] (B) is such that both ends of (B1-1) are occluded with M units (trimethylsiloxane units), and the intermediate unit is D H A linear polymethylhydrogensiloxane consisting only of units (methylhydrogensiloxane units), (B1-2) both ends occluded with M units (trimethylsiloxane units), and the intermediate units are D units (dimethylsiloxane units) and D H A linear polymethylhydrogensiloxane consisting solely of units (methylhydrogensiloxane units), where 0.1 to 2.0 moles of methylhydrogensiloxane units are present per mole of dimethylsiloxane units, or (B2-1)M H Units (dimethylhydrogensiloxane units) and Q units (SiO 4 / 2 Polymethylhydrogensiloxane consisting only of units is particularly preferred.

[0034] <Preferred embodiment of component (B)> The viscosity of component (B) is preferably 1.0 to 1000 cSt, more preferably 5 to 500 cSt, and particularly preferably 10 to 100 cSt at 23°C. When component (B) is within the above range, the adhesion to various substrates can be efficiently enhanced, the uncured composition exhibits good fluidity, and the cured composition exhibits excellent mechanical strength and appropriate elasticity and hardness. Here, if component (B) is a combination of two or more types, the viscosity of component (B) refers to the viscosity of the mixed polyorganohydrogensiloxane.

[0035] In this specification, the viscosity of component (B) is the value measured at 23°C using a Cannon-Fenske viscometer capable of measuring the viscosity range. (B) may be one type or a combination of two or more types.

[0036] <(C) Platinum catalyst> (C) The platinum catalyst is a catalyst for promoting the addition reaction between the alkenyl group in component (A) and the hydrosilyl group in component (B).

[0037] Examples of component (C) include platinum compounds such as chloroplatinic acid, reaction products of chloroplatinic acid and alcohol, platinum-alcohol complexes (Lamoreau catalyst (platinum-octanol complex)), platinum-olefin complexes, platinum-vinylsiloxane complexes (Karlsted complex, platinum-1,1,3,3-tetramethyl-1,3-divinyldisiloxane complex (platinum-methylvinylsiloxane dimer complex), Ashby complex, platinum-2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane complex (platinum-methylvinylsiloxane tetramer complex)), platinum-ketone complexes, and platinum-phosphine complexes. Of these, reaction products of chloroplatinic acid and alcohol and platinum-vinylsiloxane complexes (Karlsted complex and Ashby complex) are preferred due to their good catalytic activity. (C) Component may be one component or a combination of two or more components.

[0038] <(D) Scale-like inorganic filler with an average particle size of 100 μm or less> Component (D) is a flake-shaped inorganic filler with an average particle size of 100 μm or less. Component (D) is an ingredient that imparts oil resistance to the composition. For example, when the cured product of the composition is immersed in oil, it helps to maintain the rubber properties (i.e., tensile strength, elongation, etc.) or adhesiveness of the cured product of the composition.

[0039] In component (D), "scaly" refers to a form other than spherical, fibrous, or needle-shaped.

[0040] The average particle size of component (D) is 100 μm or less. If the average particle size of component (D) exceeds 100 μm, the composition tends to thicken significantly, reducing workability. Also, if the average particle size of the flake-like inorganic filler exceeds 100 μm, the elongation, tensile strength, or adhesive strength of the cured composition tends to decrease, resulting in reduced oil sealing properties. The average particle size of component (D) is preferably 1 μm or more and 60 μm or less, more preferably 5 μm or more and 60 μm or less, and particularly preferably 10 μm or more and 40 μm or less.

[0041] The aspect ratio of component (D) is not particularly limited and may be between 10 and 500, or between 20 and 250. The average particle size of component (D) refers to the average value of the maximum diameter of the flattened surface. The aspect ratio of component (D) refers to the ratio of the major axis to the thickness of component (D).

[0042] Component (D) includes components that can take the form of thin flakes due to their crystalline structure. Specific examples of component (D) include talc, mica, kaolin, and alumina prepared in the form of thin flakes by a synthesis process. Component (D) is preferably talc, mica, or alumina, and is particularly preferably mica. Mica is generally a flat powder. Examples of mica include natural mica such as muscovite, phlogopite, and biotite, as well as synthetic mica. Muscovite is preferred because it has few impurities and gives excellent mechanical properties to the hardened rubbery elastic material.

[0043] (D) Component may be one component or a combination of two or more components.

[0044] <Further ingredients> The composition may contain further components, as long as they do not impair the effects of the present invention. Further components include (E) acid acceptors, (F) other inorganic fillers (excluding components (D) and (E)), (G) adhesion promoters, (H) reaction inhibitors, and (I) other components.

[0045] <<(E) Acid absorber>> Component (E) is an acid acceptor. Component (E) is a component that captures acidic and basic compounds derived from additives contained in engine oil, automatic transmission oil, etc., and suppresses the decomposition of the cured silicone composition and the reduction of adhesion to various materials.

[0046] Component (E) may be an oxide or carbonate of a metal selected from Group 2 of the periodic table and transition metals. The transition metals shall include metals of Group 12. Examples of Group 2 metals include beryllium, magnesium, calcium, strontium, barium, and radium. Examples of transition metals are not particularly limited and include titanium, iron, cobalt, nickel, copper, zinc, etc.

[0047] Component (E) is preferably an oxide or carbonate of a metal selected from magnesium, calcium, iron, titanium, and zinc, as this enhances the scavenging effect of the acid component.

[0048] Component (E) preferably contains one or more selected from the group consisting of zinc oxide, titanium oxide, iron oxide, and calcium carbonate, and is particularly preferably one or more selected from the group consisting of zinc oxide, titanium oxide, iron oxide, and calcium carbonate. (E) Component may be one component or a combination of two or more components.

[0049] <<(F) Other inorganic fillers (excluding components (D) and (E))>> Component (F) is an inorganic filler other than components (D) and (E). Examples of component (F) include inorganic fillers other than flake-shaped fillers and flake-shaped inorganic fillers with an average particle diameter exceeding 100 μm. Examples of shapes other than flake-shaped fillers include spherical, fibrous, needle-shaped, etc. If component (F) has a shape other than flake-shaped fillers, its average particle diameter is defined as the particle size (D50) corresponding to a cumulative mass percentage of 50% in the particle size distribution measured based on the laser diffraction scattering method. If component (F) has a flake-shaped filler, its average particle diameter and aspect ratio can be measured by the method described for component (D).

[0050] (F) Component may include reinforcing fillers such as aerosol silica, calcined silica, silica aerogel, and precipitated silica, as well as non-reinforcing fillers such as diatomaceous earth, crushed silica, aluminosilicate, and calcium silicate, and is selected according to the ease of application and the physical properties required of the cured product. (F) Component may include reinforcing fillers, silica such as aerosol silica, calcined silica, silica aerogel, and precipitated silica is more preferred, and aerosol silica is particularly preferred.

[0051] Furthermore, the reinforcing filler may be a reinforcing filler whose surface has been hydrophobized with polyorganosiloxanes, hexamethyldisilazane, etc. (hereinafter also referred to as "hydrophobic inorganic filler"). When component (F) is a hydrophobic inorganic filler, its carbon content is preferably 1.0 to 15.0% by weight, more preferably 1.5 to 10.0% by weight, and particularly preferably 2.8 to 8.0% by weight. With such a carbon content, the hydrophobic treatment with hexamethyldisilazane, etc., is sufficient. The carbon content of the hydrophobic inorganic filler can be determined by thermally decomposing the hydrophobic groups chemically bonded to the hydrophobic inorganic filler into CO2 at 1300°C in an oxygen atmosphere, and then measuring the CO2 using a trace carbon analyzer.

[0052] The BET specific surface area of ​​component (F) (also referred to simply as "specific surface area" in this specification) is 50 to 500 m². 2 It is preferable that the specific surface area of ​​component (F) is within the above range. When the specific surface area of ​​component (F) is within the above range, the composition has appropriate fluidity and the cured product is given high mechanical strength. The specific surface area of ​​component (F) is 50 to 500 m². 2 It is preferable that the value be / g, and 80-400m 2 It is more preferable that it be / g, and 100-300m 2 It is even more preferable that the amount be / g, and 110-240m 2 It is particularly preferable that the value be / g. (F) Component may be one component or a combination of two or more components.

[0053] <<(G) Adhesion-improving agent>> (G) The adhesion-imparting agent is a component that imparts adhesion to various substrates to the composition. It is preferable that component (G) includes at least one selected from the group consisting of components (G1) to (G4) below.

[0054] (G1) A hydrogen atom bonded to a silicon atom and the following formula (1): [ka] An organosilicon compound having a side chain represented by, (G2)Si(OR 3 ) n Organosilicon compounds having a group and an epoxy group-containing group, and / or partially hydrolyzed condensates thereof, (G3)Si(OR 3 ) n Silane compounds having a group and an aliphatic unsaturated hydrocarbon group, and / or partially hydrolyzed condensates thereof, (G4)Si(OR 4 A tetraalkoxysilane compound represented by 4, and / or a partially hydrolyzed condensate thereof. (In each formula above, L 1 L represents a linear or branched alkylene group that forms a carbon chain having two or more carbon atoms between a silicon atom and an ester bond; 2 R represents a linear or branched alkylene group that forms a carbon chain having three or more carbon atoms between the oxygen atom and the silicon atom of the side chain; 3 R represents an alkyl group having 1 to 4 carbon atoms or a 2-methoxyethyl group; 4 (where n represents an alkyl group with 1 to 3 carbon atoms; n is an integer between 1 and 3.)

[0055] Components (G1), (G2), (G3), and (G4) may each consist of one or more types. For example, component (G) may be a combination of one (G1) component, two (G2) components, and two (G3) components.

[0056] <<(G1) Ingredients>> Component (G1) undergoes an addition reaction with component (A) during the curing of the composition and is introduced into the siloxane structure crosslinked by the addition reaction with components (A) and (B). The side chain of formula (1) is the part that exhibits adhesiveness and contributes to the adhesion of the composition. In addition, the alkoxy group (hereinafter referred to as OR) present in the side chain of component (G1) 3 (where represents an alkoxy group or 2-methoxyethoxy group having 1 to 4 carbon atoms) also contribute to the introduction of components (G2), (G3), and / or (G4) into the siloxane structure through co-hydrolysis and condensation reactions with the alkoxy groups of components (G2), (G3), and / or (G4).

[0057] L 1 Ethylene groups and 2-methylethylene groups are preferred because they are easy to synthesize and handle. 2 Trimethylene groups are preferred because they are easy to synthesize and handle. 3 Because it provides good adhesion and the alcohol produced by hydrolysis is easily volatile, methyl and ethyl groups are preferred, with methyl groups being particularly preferred.

[0058] The hydrogen atoms and side chains characteristic of component (G1) are preferably bonded to separate silicon atoms, as this facilitates synthesis. Therefore, the basic portion of component (G1) preferably forms a chain-like, branched, or cyclic siloxane skeleton, and a cyclic siloxane skeleton is particularly preferred because it allows for controlled synthesis and purification of specific compounds. The number of Si-H bonds in component (G1) is one or more, and in the case of cyclic siloxane compounds, two or three bonds are preferred.

[0059] The following compounds are examples of component (G1). [ka]

[0060] <<(G2) component>> Component (G2) is introduced into the crosslinked siloxane structure through a co-hydrolysis and condensation reaction between an alkoxy group bonded to a silicon atom and the alkoxy groups bonded to the silicon atoms of components (G1), (G3), and / or (G4). The epoxy group acts as the part that exhibits adhesiveness, contributing to the improvement of the adhesion of the composition.

[0061] R 3 Since it provides good adhesion, methyl and ethyl groups are preferred, with methyl groups being particularly preferred. n is preferably 2 or 3. As for epoxy group-containing groups, aliphatic epoxy group-containing groups containing an ether oxygen atom, such as 3-glycidoxypropyl group; and alicyclic epoxy group-containing groups, such as 2-(3,4-epoxycyclohexyl)ethyl group are preferred because they are easy to synthesize, not hydrolyzable, and exhibit excellent adhesion. Si(OR 3 ) n The group may have two or more elements in the molecule. 3 The number of groups in the molecule is preferably two or more. 3 The group and the epoxy group-containing group may be bonded to the same silicon atom or to different silicon atoms.

[0062] (G2) components include alkoxysilanes containing 3-glycidoxypropyl groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyl(methyl)dimethoxysilane; alkoxysilanes containing 2-(3,4-epoxycyclohexyl)ethyl groups such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyl(methyl)dimethoxysilane; partially hydrolyzed condensates of these silanes with n of 2 or more; and carbon / silicon bifunctional siloxanes in which some of the methyl groups of a linear or cyclic methylsiloxane are replaced with a trimethoxysiloxy group or a 2-(trimethoxysilyl)ethyl group and the epoxy group-containing group mentioned above.

[0063] <<(G3) component>> Component (G3) undergoes an addition reaction with component (B) during the curing of the composition, and is introduced into the siloxane structure crosslinked by the addition reaction with components (A) and (B). The alkoxy group present in the side chain acts as the adhesive portion, contributing to the improvement of the composition's adhesion. Furthermore, the alkoxy group of component (G3) also contributes to the introduction of components (G1), (G2), and / or (G4) into the siloxane structure crosslinked by components (G1), (G2), and / or (G4) through co-hydrolysis and condensation reactions with the alkoxy groups of other components (G3) and (G2). When the alkoxy group is used in combination with other alkoxy groups of component (G3) and component (G2), it introduces the other components (G3) and / or (G2) into the siloxane structure through co-hydrolysis and condensation reactions with the alkoxy group of component (G2).

[0064] R 3 The group provides good adhesion, so methyl and ethyl groups are preferred, with methyl groups being particularly preferred. n is preferably 2 or 3. The aliphatic unsaturated hydrocarbon group is preferably a monovalent group. In the case of alkenyl groups such as vinyl, allyl, and 3-butenyl, the aliphatic unsaturated hydrocarbon group may be directly bonded to the silicon atom, or, as in 3-acryloxypropyl and 3-methacryloxypropyl, an unsaturated acryloxy group may be bonded to the silicon atom via three or more carbon atoms. As unsaturated hydrocarbon group-containing groups, vinyl groups, methacryloxypropyl groups, etc. are preferred because they are easy to synthesize and handle. Si(OR 3 ) n The group may have two or more elements in the molecule. 3 The number of groups in the molecule is preferably two or more. 3 The group and the aliphatic unsaturated hydrocarbon group may be bonded to the same silicon atom or to different silicon atoms.

[0065] Examples of component (G3) include alkenylalkoxysilanes and / or their partial hydrolysis condensates, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, methylvinyldimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, and methylallyldimethoxysilane; and (meth)acryloxypropyl(methyl)di- and (meth)acryloxypropyltri-alkoxysilanes and / or their partial hydrolysis condensates, such as 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyl(methyl)dimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-methacryloxypropyl(methyl)dimethoxysilane.

[0066] <<(G4) Ingredients>> Component (G4) is an ingredient that further improves the adhesion of the composition. 4 Examples of alkyl groups include linear or branched alkyl groups such as methyl, ethyl, propyl, and isopropyl. Methyl and ethyl groups are preferred because they are readily available, easy to handle, and significantly improve adhesion. Furthermore, while component (G4) can be used as a tetraalkoxysilane compound alone, it is preferable that it be a partially hydrolyzed condensate of a tetraalkoxysilane compound due to its excellent hydrolysis properties and lower toxicity.

[0067] <<Other adhesion promoters>> Other adhesion-imparting agents besides components (G1) to (G4) include metal alkoxides and metal chelates. Specific examples include aluminum alkoxides such as aluminum triethoxide, aluminum trippropoxide, and aluminum tributoxide; titanium alkoxides such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide, and titanium tetraisopropenyloxide; zirconium acylates such as zirconium octanoate, tetra(2-ethylhexanoate) zirconium, and zirconium stearate; zirconium alkoxides such as n-propyl zirconate and n-butyl zirconate (excluding zirconium chelates); and zirconium chelates such as tributoxyzirconium acetylacetonate, dibutoxyzirconium bis(ethylacetoacetate), zirconium tetraacetylacetonate, zirconium monoacetylacetonate, and zirconium ethylacetoacetate. Furthermore, zirconium chelates may have alkoxy groups insofar as they contain one or more chelate ligands (e.g., C5H7O2, C6H9O3, etc.) in their molecule.

[0068] Other adhesion-improving agents include, [ka] [ka] Compounds having hydrolyzable silyl groups and reactive organic functional groups in their molecules and / or partially hydrolyzed condensates thereof (but not including components (G1) to (G4)); [ka] Compounds having a hydrogen atom bonded to a silicon atom and a reactive organic functional group in the molecule; [ka] Examples include compounds having a hydrogen atom bonded to a silicon atom and a divalent aromatic group in a single molecule (wherein k is an integer from 1 to 3). The adhesive strength can be further enhanced by using other adhesion promoters in combination.

[0069] <<Preferred Embodiment>> Component (G) preferably includes a combination of components (G1), (G2), (G3), and / or (G4). Components (G1) to (G4) may each be one or a combination of two or more.

[0070] <<(H) Reaction Inhibitor>> (H) Examples of reaction inhibitors include organic compounds having polar groups in their molecules, such as diallyl maleate; and organic compounds having unsaturated bonds, such as acetylene alcohols and their derivatives. Reaction inhibitors suppress the curing reaction rate of the composition, contributing to improved handling workability and a better balance between adhesion development and curing speed.

[0071] <<(J) Other further ingredients>> (J) Other further components are components other than components (F), (G), and (H). Examples of component (J) include (J1) polyorganosiloxanes having one alkenyl group bonded to a silicon atom in the molecule, (J2) polyorganohydrogensiloxanes having two hydrogen atoms bonded to a silicon atom in the molecule, organic solvents, pigments, conductive fillers such as carbon black, thixotropy imparters, viscosity modifiers to improve coating workability, ultraviolet absorbers, antifungal agents, heat resistance improvers, flame retardants, etc.

[0072] (J1) A polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule. The siloxane skeleton in component (J1) is as described above for component (A), including preferred embodiments.

[0073] Component (J1) is preferably a linear polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule. Component (J1) has one end which is R 1 R 2 2SiO 1 / 2 It is sealed as a unit, and the other end is R 2 3SiO 1 / 2 The unit is sealed, and the intermediate unit is R 2 2SiO 2 / 2 It is more preferable that the (J1) component is a linear polyorganosiloxane consisting only of units. vi D n It is particularly preferable that the linear polyorganosiloxane is represented by M.

[0074] (J2) A polyorganohydrogensiloxane having two hydrogen atoms bonded to a silicon atom in the molecule. Component (J2) can function as a chain extender by reacting with (A), etc., through an addition reaction. Component (J2) is as described for component (B), except that it has two hydrogen atoms bonded to silicon atoms in its molecule. Component (J2) has two units represented by the general formula (II) described above in (B).

[0075] The siloxane skeleton in component (J2) may be linear, branched, or cyclic, with linear being preferred. Furthermore, both ends of component (J2) independently contain R 6 3SiO 1 / 2 The unit is closed, and the intermediate unit is R 6 2SiO 2 / 2 Consists of units only (in the formula, R 6 Each of these is independently a monovalent hydrocarbon group that does not have a hydrogen atom or an aliphatic unsaturated bond, however, R 6 It is more preferable that the (J2) component is a linear polyorganohydrogensiloxane (of which two are hydrogen atoms). The hydrogen atoms bonded to the silicon atoms may be located at the ends or in intermediate units, but it is preferable that they be located at the ends. Therefore, the (J2) component is one in which both ends are M HIt is particularly preferable that the polymethylhydrogensiloxane is occluded by units (dimethylhydrogensiloxane units) and the intermediate units consist only of D units (dimethylsiloxane units).

[0076] Organic solvents Organic solvents are components that can dissolve or disperse other components in a composition. Examples of organic solvents include aromatic organic solvents such as toluene and xylene.

[0077] Other components (J) can be appropriately selected from the components used in addition-curing silicone compositions.

[0078] [Content] The following are preferred content levels for each component in the addition-curing silicone composition.

[0079] The content of component (A) is preferably 10 to 5,000 parts by mass, more preferably 50 to 4,000 parts by mass, and particularly preferably 100 to 3,000 parts by mass, based on 100 parts by mass of the total of components (B), (C), and (D).

[0080] The content of component (A2) is preferably 0 to 80 parts by mass, and particularly preferably 0 to 60 parts by mass, based on 100 parts by mass of the total of components (A1) and (A2). If the content of component (A2) is 80 parts by mass or less, the crosslinking density does not become too high, and the flexibility of the cured product is better.

[0081] The content of component (B) is preferably such that the ratio of the number of hydrogen atoms (H) bonded to the silicon atoms of component (B) to the number of alkenyl groups (Vi) of component (A) (H / Vi) is 0.1 or more and less than 10, more preferably 0.2 to 5, and particularly preferably 0.5 to 3.0. When the H / Vi ratio in the composition is 0.1 or more, the mechanical strength of the cured product tends to be excellent, and when it is less than 10, the adhesion of the composition to various materials tends to be improved.

[0082] The content of component (C) is preferably 0.1 to 1,000 ppm by weight, and particularly preferably 0.5 to 200 ppm by weight, relative to component (A) in terms of platinum metal atoms. When the content of component (C) is within the above range, sufficient curability is likely to be achieved.

[0083] The content of component (D) is preferably 1 to 200 parts by mass, more preferably 3 to 100 parts by mass, and particularly preferably 5 to 80 parts by mass, per 100 parts by mass of component (A). When the content of component (D) is within the above range, the oil resistance tends to improve further. In addition, when the content of component (D) is within the above range, the curability of the composition tends to improve further, and the workability tends to improve.

[0084] The content of component (E) is preferably 0 to 200 parts by mass, more preferably 5 to 150 parts by mass, and particularly preferably 10 to 100 parts by mass, per 100 parts by mass of component (A). When the content of component (E) is within the above range, acidic compounds and basic substances can be efficiently captured, and the oil resistance tends to be further improved. In addition, when the content of component (E) is within the above range, the curability of the composition tends to be further improved, and the workability tends to be improved.

[0085] The content of component (F) is preferably 0 to 80 parts by mass, more preferably 0.5 to 50 parts by mass, and particularly preferably 1 to 30 parts by mass, per 100 parts by mass of component (A). When the content of component (F) is within the above range, for example, if component (F) is aerosolized silica, the physical strength of the cured composition tends to be higher.

[0086] Furthermore, the total content of components (D), (E), and (F) relative to the entire composition is preferably 0.1 to 80% by mass, more preferably 10 to 60% by mass, even more preferably 20 to 60% by mass, and particularly preferably 28 to 60% by mass. When the total content of components (D), (E), and (F) is within the above range, the deterioration of physical properties when continuously in contact with automotive oils such as engine oil, gear oil, and automatic transmission fluid in the automobile engine is suppressed. Note that if the composition does not contain component (E), the content of component (E) in the above is zero. The same applies to component (F).

[0087] If the composition contains components (G1), (G2), and / or (G3), the total amount of components (G1), (G2), and / or (G3) is preferably 0.1 to 20 parts by mass, and particularly preferably 0.5 to 10 parts by mass, per 100 parts by mass of component (A). Within this range, sufficient adhesion after heat curing from room temperature to 200°C is easily achieved, and the mechanical strength and flexibility of the cured product of the composition are easily improved. Furthermore, if the composition contains component (G4), the content of component (G4) is preferably 0.01 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, per 100 parts by mass of component (A), as it imparts excellent adhesion to metal to the cured silicone rubber. Furthermore, if component (G) is a mixture of two components selected from the group consisting of components (G1) to (G4), it is preferable that the weight ratio of one component (G1) to (G4) is in the range of 0.02 to 50 times that of the other in order to obtain good adhesion. Also, if component (G) is a mixture of three or four components selected from the group consisting of components (G1) to (G4), it is preferable that each component is included in an amount of 3% by mass or more of component (G). Furthermore, when considering the content of component (G), if the composition contains component (A) that functions as component (G), the content of the component that functions as component (G) shall be excluded from the content of component (A). The same shall apply if the composition contains component (B) that functions as component (G).

[0088] The content of components (H) and (J) is not particularly limited as long as it does not impair the intended use of the composition.

[0089] The viscosity of the composition is not particularly limited and can be adjusted as appropriate depending on the application, ranging from fluid to semi-fluid and non-fluid.

[0090] (Method for manufacturing addition-curing silicone composition) Addition-curing silicone compositions can be manufactured by uniformly kneading one or more components selected from the group consisting of essential components (A), (B), (C), and (D), and optional components (F), (G), (H), and (J), using a mixing means such as a universal kneader or a kneader.

[0091] (cured product) A cured product obtained by curing an addition-curing silicone composition can be obtained by curing the addition-curing silicone composition. The curing conditions (i.e., heating temperature and heating time) can be appropriately adjusted according to the heat resistance temperature of the component to which the addition-curing silicone composition is applied. From the viewpoint of the heat resistance and operability of the component, the heating temperature is preferably 20 to 200°C, and particularly preferably more than 23°C and 150°C or less. The heating time depends on the amount of material to be cured and the heating output of the curing equipment, but from the viewpoint of simplicity of the curing process, it is preferably 15 minutes to 3 hours, and particularly preferably 30 minutes to 2 hours.

[0092] (Application) Cured products of addition-curing silicone compositions exhibit excellent oil resistance, thus preventing deterioration of their properties even when in contact with automotive oils. Therefore, addition-curing silicone compositions can be used as sealing materials for automotive parts. Specifically, addition-curing silicone compositions can be used as oil sealing materials for automotive parts that come into contact with automotive oils. Examples of automotive oils include engine oil, gear oil, and automatic transmission fluid (ATF oil). [Examples]

[0093] The present invention will be described in further detail below with reference to examples and comparative examples. In these examples, parts represent parts by mass, and viscosity represents viscosity at 23°C. The present invention is not limited to these examples.

[0094] (Ingredients used) The components used in the examples and comparative examples are as follows: (A) Alkenyl group-containing polyorganosiloxane A-1:M vi D n M vi Linear polymethylvinylsiloxane A-1-1, represented by (wherein n is a value such that the viscosity at 23°C is 100 Pa·s), and M units, D vi It consists only of units and Q units, and the molar unit ratio is M5D vi A mixture of branched polymethylvinylsiloxane A-2-1 (weight-average molecular weight 4,000, average of 4 vinyl groups per molecule) as shown in Q8 (weight ratio A-1-1:A-2-1 = 75:25) A-2:M vi D n M vi Linear polymethylvinylsiloxane A-1-2, represented by (wherein n is a value such that the viscosity at 23°C is 3 Pa·s), and M units, D vi It consists only of units and Q units, and the molar unit ratio is M5D vi A mixture with branched polymethylvinylsiloxane A-2-1 (weight-average molecular weight 4,000, average of 4 vinyl groups per molecule) as shown in Q8 (weight ratio A-1-2:A-2-1 = 60:40) A-3: Linear polymethylvinylsiloxane A-1-1 A-4:M vi D n M vi Linear polymethylvinylsiloxane A-1-3 (wherein n is a value such that the viscosity at 23°C is 10 Pa·s) (B) Polyorganohydrogensiloxane B:MD H 23 D 16 A linear polymethylhydrogensiloxane (an average of 23 hydrogen atoms per molecule) denoted by M, with a viscosity of 20 cSt at 23°C. (C) Platinum catalyst C: Platinum-octanol complex (Lamoreau catalyst, platinum content 3.4% by mass) (D) Scale-like inorganic fillers with an average particle size of 50 μm or less D: Mica (Yamaguchi Mica Co., Ltd. A-21, average particle size: 25 μm, aspect ratio 70)

[0095] (E) Acid absorber E-1: Titanium dioxide (Ishihara Sangyo Co., Ltd., Typeque A-100, average particle size: 0.15 μm) E-2: Zinc oxide (Mitsui Mining & Smelting Co., Ltd., Zinc Oxide No. 1, Average particle size: 0.75 μm) E-3: Iron oxide (LANXESS Corporation, BAYFERROX 130M) E-4: Calcium carbonate (Nitto Powdering Industry Co., Ltd., NS#400, average particle size: 1.7 μm) (F) Other inorganic fillers F-1: Specific surface area 200m 2 Silica (unsurface-treated) of 1 / g atomized silica (surface area 150m²) surface-treated with hexamethyldisilazane (HMDZ) 2 / g, carbon content 3.8% by weight) <Carbon Content> The carbon content of the surface-treated inorganic filler was determined by thermally decomposing the hydrophobic groups chemically bonded to the silica surface into CO2 at 1300°C in an oxygen atmosphere, and then measuring the amount of CO2 using a trace carbon analyzer (HORIBA "EMIA-110"). F-2: Crushed quartz (Ryumori Co., Ltd. CRYSTALITE VX-S, average particle size: 5μm)

[0096] (G) Adhesion-improving agent G-1: Vinyltriethoxysilane G-2:3-Glycidoxypropyltrimethoxysilane G-3:Formula: [ka] Cyclic siloxanes represented by G-4: Tetraethoxysilane (H) Reaction inhibitor H-1: Surfinol 61 H-2: Diallyl maleate H-3: Triallyl isocyanurate

[0097] (Method for preparing the composition) The entire contents of component (A), component (D), component (E), and component (F) were transferred to a universal kneader and stirred at room temperature (23°C; the same applies hereafter) for 60 minutes, then stirred under reduced pressure at 150°C for 60 minutes. After cooling to room temperature below 30°C, component (C) was added and stirred at room temperature for 30 minutes, then the entire contents of component (H) were added and stirred at room temperature for 30 minutes. Furthermore, the entire contents of components (B) and (G) were added and stirred at room temperature for 10 minutes to prepare the addition-curing silicone composition.

[0098] (Evaluation method) Adhesion test <Creation of rubber pieces for tensile properties> The prepared silicone composition was poured into a metal container (aluminum) measuring 150 mm (length) x 150 mm (width) x 2 mm (depth) coated with Teflon®, and a metal lid, also coated with Teflon®, was placed over it. The mixture was then cured in a hot air circulating dryer at 150°C for 1 hour. After cooling to room temperature, the cured material was removed from the mold, and a 2 mm thick evaluation rubber piece was prepared by punching it out in a dumbbell shape (size 2) in accordance with JIS K6249:2003.

[0099] <Preparation of adhesive test specimens> In accordance with JIS K6249:2003, test specimens for shear adhesion testing were prepared as follows. Specifically, they were prepared as follows: Silicone compositions were filled into cokers respectively. Two metal plates (80 mm × 25 mm × 2 mm) of aluminum test specimens (A1050P) were prepared. On one side of one metal plate, the composition was extruded from the coker and applied so that the application length from one short side was 10 mm, the applied part was 25 mm × 10 mm, and the thickness was 1.0 mm. Another metal plate was overlapped on the part where the composition was applied from one short side so that the bonding part was 25 mm × 10 mm, and the overlapped part was fixed with a jig. The resin plate fixed in this way was heated at 150°C for 1 hour to cure the composition and bond the metal plates together to obtain test specimens.

[0100] <ATF 150°C Immersion Test> Dumbbell-shaped rubber pieces and test specimens for shear adhesion tests were immersed in Toyota-made ATF oil WS and subjected to accelerated tests at 150°C for 100 and 250 hours, and were used for the evaluation of the tensile properties, shear adhesion tests, and cohesion failure rates of the following rubber pieces.

[0101] Evaluation Tests One day after production for initial evaluation, and each test specimen after 100 and 250 hours of accelerated tests after immersion in 150°C ATF was returned to room temperature.

[0102] <Tensile Property Test> In accordance with JIS K6249:2003, for hardness (Type A), the above rubber pieces were stacked three layers to a thickness of 6 mm for measurement, and for tensile strength and elongation at break, they were measured as they were (2 mm thick).

[0103] <Shear Adhesion Test> In accordance with JIS K6249:2003, the shear adhesion force (lap share strength) was evaluated. However, the tensile speed was 10 mm / min.

[0104] <Evaluation of Cohesion Failure Rate> The bonding surface of the test specimens after the shear bonding test was observed, and the cohesive failure rate was evaluated as the percentage of the total bonding area to which the cured material adhered to the aluminum metal plate. The cohesive failure rate was calculated as a value in 10% increments. A higher cohesive failure rate indicates stronger adhesion at the interface between the aluminum metal plate and the cured material of the composition.

[0105] The results are summarized in the table. "-" indicates that the measurement was not taken. "Filler content" refers to the total content of components (D), (E), and (F) relative to the total amount of the composition. The decrease in tensile strength was calculated using the formula: "Initial tensile strength - Tensile strength after 100 hours or 250 hours of treatment = Decrease in tensile strength (MPa)". The percentage decrease in tensile strength was calculated using the formula: "Decrease in tensile strength ÷ Initial tensile strength × 100 = Percentage decrease in tensile strength (%)".

[0106] [Table 1]

[0107] As is clear from the table, the addition-curing silicone composition of the example showed a small decrease in tensile strength and excellent oil resistance after treatment at 150°C. Furthermore, the addition-curing silicone composition of the example showed excellent shear adhesion and cohesive failure rate after 250 hours of treatment. Moreover, the shear adhesion and cohesive failure rate after 100 hours of treatment were even better than those after 250 hours.

[0108] When comparing Comparative Example 1 with Examples 1-3 after treatment at 150°C for 100 hours, the decrease in tensile strength was smaller for Examples 1-3. Therefore, it can be seen that Examples 1-3 had superior oil resistance compared to Comparative Example 1.

[0109] When comparing Examples 1-2 and Example 3 after treatment at 150°C for 100 hours, Example 3 showed a smaller decrease in tensile strength and superior oil resistance. Furthermore, when comparing Examples 1 and Examples 3-6 after treatment at 150°C for 250 hours, Examples 3-6 showed a smaller decrease in tensile strength and superior oil resistance.

[0110] In a 250-hour treatment at 150°C, a comparison of Example 1 with Examples 3, 5, and 6 showed that when the composition contained (E-2) zinc oxide and / or (E-3) iron oxide, the rate of decrease in tensile strength was smaller and the oil resistance was superior. A comparison of Example 3 with Example 6 showed that when component (E) contained (E-2) zinc oxide, the rate of decrease in tensile strength was smaller and the oil resistance was superior. Furthermore, a comparison of Examples 3 and 6 with Example 5 showed that when the composition contained both (E-2) zinc oxide and (E-3) iron oxide, the rate of decrease in tensile strength was smaller and the oil resistance was superior. Examples 4 and 5 show the same rate of decrease in tensile strength. A comparison between Example 4 and Example 5 revealed that when component (A) contains a larger proportion of component (A2), the decrease in tensile strength is smaller, and the oil resistance is superior.

[0111] On the other hand, in the 150°C 100-hour treatment, Comparative Example 1 exhibited inferior oil resistance compared to Examples 1-3. Furthermore, considering the results of Examples 1 and 3 in the 150°C 100-hour and 150°C 250-hour treatments, the rate of decrease in tensile strength increased with longer treatment times. Therefore, it is clear that in Comparative Example 1, when the treatment time was 250 hours, the oil resistance was inferior compared to Examples 1-6.

Claims

1. (A) Polyorganosiloxanes having two or more alkenyl groups bonded to silicon atoms in the molecule; (B) Polyorganohydrogensiloxanes containing three or more hydrogen atoms bonded to silicon atoms in the molecule; (C) Platinum catalyst; and (D) Scale-like inorganic fillers with an average particle size of 100 μm or less An addition-curing silicone composition containing the above.

2. Furthermore, the addition-curing silicone composition according to claim 1, further comprising (E) an acid acceptor.

3. (E) The addition-curing silicone composition according to claim 1, wherein the acid acceptor comprises one or more selected from the group consisting of zinc oxide, titanium oxide, iron oxide, and calcium carbonate.

4. Furthermore, the addition-curing silicone composition according to claim 1, comprising one or more selected from the group consisting of (F) other inorganic fillers (excluding components (D) and (E)), (G) adhesion promoters, and (H) reaction inhibitors.

5. (A) Component is (A1) Both ends are R ３ SiO １／２ The unit is sealed off, and the intermediate unit is R ２ ２ SiO ２／２ The unit is a linear polyorganosiloxane, (A2) SiO ４／２ units and R ３ SiO １／２ units, and as optional units R ２ SiO ２／２ units and / or RSiO ３／２ units, comprising a branched polyorganosiloxane The addition-curing silicone composition according to claim 1, comprising:

6. A cured product obtained by curing an addition-curing silicone composition according to any one of claims 1 to 5.

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