Silicone composition and cured article

Abstract

The present disclosure provides a silicone composition and a cured article obtained by curing the silicone composition. Provided in some embodiments disclosed in the present specification are a cured article with excellent chemical resistance, and a silicone composition capable of forming the cured article. The silicone composition according to the present disclosure comprises: (A) an organohydrogenpolysiloxane that has a cyanoalkyl group and a hydrogen atom directly bonded to a silicon atom and has a prescribed chemical structure; (B) an organopolysiloxane that has two or more alkenyl groups per molecule; and (C) a curing catalyst.

Description

Silicone composition and cured product

[0001] The present disclosure relates to a silicone composition and a cured product thereof.

[0002] In this section, background information related to the present disclosure is provided, which is not necessarily prior art. Silicone compositions are known to form cured products having excellent heat resistance, cold resistance, electrical insulation, weather resistance, water repellency, and transparency, and are used in a wide range of fields. For example, in Patent Document 1, a curable silicone composition containing an organopolysiloxane containing a cyanoalkyl group and a monovalent hydrocarbon group having an aliphatic unsaturated bond, an organohydrogenpolysiloxane represented by a predetermined average composition formula and containing a cyanoalkyl group, and a platinum group metal-based catalyst is disclosed. And according to the literature, the curable silicone composition is excellent in handleability, and it is reported that a cured product obtained by heating the composition at, for example, 100 ° C or higher exhibits excellent dielectric properties.

[0003] Japanese Patent Application Laid-Open No. 2002-265788

[0004] The present disclosure provides a silicone composition and a cured product obtained by curing the silicone composition.

[0005] In a first aspect, a silicone composition is disclosed. The silicone composition according to the embodiments disclosed herein comprises the following components (A) to (C): (A) the following formula (I): 〔In the above formula (I), R １ are each independently an alkyl group or an aromatic hydrocarbon group, R ２ is a cyanoalkyl group, x is 0.0 or more and 50.0 or less, y is 1.0 or more and 100.0 or less, and z is 1.0 or more and 50.0 or less.〕 a cyano group-containing organohydrogenpolysiloxane represented by, (B) an organopolysiloxane having two or more alkenyl groups per molecule, and (C) a curing catalyst.

[0006] In a second embodiment, a cured product is disclosed. The cured product according to the embodiments disclosed herein can be obtained by curing the silicone composition of the first embodiment of this disclosure. These and other embodiments are described in detail below.

[0007] This disclosure provides silicone compositions and cured products obtained by curing the silicone compositions. In some embodiments disclosed herein, cured products with excellent chemical resistance and silicone compositions capable of forming such cured products can be provided.

[0008] Unless otherwise stated, implied in the context, or customary in the art, all "parts" and "%" are based on weight, all temperatures are in "°C", and all test methods are current as of the filing date of this disclosure. In this disclosure, the term "composition" refers to a mixture of materials constituting the composition, as well as reaction and decomposition products formed from the materials of the composition. In this disclosure, the term "polymer" refers to a compound prepared by polymerizing identical or different types of monomers. In this disclosure, the term "organopolysiloxane" refers to a polymer containing multiple siloxane bonds and having at least one organic group. Organopolysiloxanes are SiO ４／２ (“Q” type), RSiO ３／２ (“T” type), R ２ SiO ２／２ (Type "D"), and R ３ SiO １／２The D-type siloxane unit includes a siloxane unit selected from those known in the art as ("M" type). The subscript R group indicates the number of R groups bonded to the silicon atom. The subscript oxygen indicates the number of oxygen atoms bonded to the silicon (i.e., how the silicon atom participates in the siloxane bond, "Si-O-Si" bond), and since the oxygen is shared with another silicon atom, it is considered that only half of each oxygen is bonded to each silicon atom, so the number is divided by two. Thus, a D-type siloxane unit contains a silicon atom bonded to two R groups and two and a half oxygen atoms, since it shares two oxygen atoms with another silicon atom. In general, the R group can be any substituent other than -OSi (i.e., a siloxane bond to silicon). In general, the R group is a hydrocarbyl bonded to a silicon atom via hydrogen or a carbon-silicon bond. However, in the broadest sense herein, the R group can also be a group bonded to a silicon atom with an atom other than hydrogen or carbon, such as sulfur or oxygen. For example, the R group can be selected from a hydroxyl group or an alkoxyl group, which are collectively referred to as the "OZ" group. In this disclosure, the term "organohydrogenpolysiloxane" refers to an organopolysiloxane having at least one hydrogen atom directly bonded to a silicon atom (hereinafter sometimes referred to as "silicon-bonded hydrogen atom"). In this disclosure, the term "chemical resistance" means resistance to swelling in toluene, which can be evaluated by the method described in the examples below. In this disclosure, the term "photocuring catalyst" means a compound that promotes the hydrosilylation reaction between an alkenyl group and a silicon-bonded hydrogen atom by irradiation with electromagnetic waves such as light (e.g., ultraviolet (UV) and visible light) or electron beams. In some embodiments, the photocuring catalyst may be a compound that promotes the hydrosilylation reaction at a temperature of 35°C or below, or 10 to 35°C, or 15 to 25°C by irradiation with electromagnetic waves or electron beams. In this disclosure, the term "thermosetting catalyst" means a compound that, when heated, promotes a hydrosilylation reaction between an alkenyl group and a silicon-bonded hydrogen atom.In some embodiments, the thermosetting catalyst may be a compound that promotes the above hydrosilylation reaction without irradiation with light. In some embodiments, the thermosetting catalyst may be a compound that promotes the above hydrosilylation reaction in a temperature range above 35°C, or above 40°C, or above 50°C. Also, in some embodiments, from the definition of "thermosetting catalyst", a compound that promotes the hydrosilylation reaction between an alkenyl group and a silicon-bonded hydrogen atom by irradiation with electromagnetic waves such as light (e.g., ultraviolet (UV) or visible light) or electron beams may be excluded. In the present disclosure, the term "silicone composition" refers to a composition containing an organopolysiloxane. In the present disclosure, the chemical structure of the organopolysiloxane is standard. １ H, １３ C, and ２９ It can be determined by Si nuclear magnetic resonance (NMR) analysis. In the present disclosure, the weight average molecular weight and the number average molecular weight refer to polystyrene conversion values measured by gel permeation chromatography using toluene as the developing solvent. In the present disclosure, the viscosity refers to the value measured at 25°C using a B-type viscometer in accordance with the provisions of JIS K 7117-1:1999. In the present disclosure, the kinematic viscosity refers to the value measured at 25°C using an Ubbelohde viscometer in accordance with the provisions of JIS Z8803.

[0009] (Silicone Composition) The present disclosure provides a silicone composition. In some embodiments, the silicone composition is curable, and the cured product obtained from the silicone composition can exhibit excellent chemical resistance.

[0010] The silicone composition contains (A) a cyano group-containing organohydrogenpolysiloxane, (B) an organopolysiloxane, and (C) a curing catalyst. The silicone composition may optionally contain components other than components (A) to (C). In the present disclosure, "(A) cyano group-containing organohydrogenpolysiloxane" may be abbreviated as "(A) cyano group-containing polysiloxane", "(B) organopolysiloxane" may be abbreviated as "(B) polysiloxane", and "components other than components (A) to (C)" may be abbreviated as "other components", respectively.

[0011] <(A) Cyano group-containing organohydrogen polysiloxane> (A) cyano group-containing polysiloxane has silicon-bonded hydrogen atoms. In some embodiments, the silicon-bonded hydrogen atoms in (A) cyano group-containing polysiloxane react with the alkenyl groups of (B) polysiloxane by a curing reaction (hydrosilylation reaction) in the presence of (C) curing catalyst. In addition, (A) cyano group-containing polysiloxane has a cyanoalkyl group. It is presumed that due to this cyanoalkyl group, the cured product obtained from the silicone composition can exhibit excellent chemical resistance. Note that (A) cyano group-containing polysiloxane may be used alone or in combination of any selected multiple types.

[0012] Furthermore, (A) the cyano group-containing polysiloxane has the chemical structure of the following formula (I).

[0013] In the above formula (I), R １ Each of these is independently an alkyl group or an aromatic hydrocarbon group, and R ２ A is a cyanoalkyl group, where x is between 0.0 and 50.0, y is between 1.0 and 100.0, and z is between 1.0 and 50.0.

[0014] Note that the above formula (I) is a combination of three types of D-type siloxane units (i.e., (R １ ２ SiO ２／２ ) Unit, (R １ R ２ SiO ２／２ ) units and (R １ HSiO ２／２ This does not specify the bonding order of the units. Formula (I) above specifies the average number of each of the three types of D-type siloxane units per molecule. In other words, in (A) cyano group-containing polysiloxane, the three types of D-type siloxane units may exist forming blocks, or the three types of D-type siloxane units may exist in any bonding order (i.e., randomly).

[0015] In the above formula (I), (R １ ２SiO ２／２ ) The unit does not have to exist, or there may be only one type of unit, or there may be two or more types. In the above formula (I), (R １ R ２ SiO ２／２ ) There may be only one type of unit, or there may be two or more types. In the above formula (I), (R １ HSiO ２／２ There may be only one type of unit, or there may be two or more types.

[0016] In the above formula (I), R １ As mentioned above, each is independently an alkyl group or an aromatic hydrocarbon group. １ Non-limiting examples of alkyl groups that can constitute the R include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and combinations thereof. １ Non-limiting examples of aromatic hydrocarbon groups that can constitute R include phenyl groups, tolyl groups, xylyl groups, naphthyl groups, and combinations thereof. In some embodiments, R １ This may be an alkyl group, or selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group, or it may be a methyl group.

[0017] In the above formula (I), R ２ As described above, is a cyanoalkyl group. In some embodiments, the number of carbon atoms in the cyanoalkyl group may be 1 or more, or 2 or more, or 3 or more. At the same time, the number of carbon atoms in the cyanoalkyl group may be 9 or less, or 6 or less, or 5 or less. In some embodiments, R ２This may be a cyanoalkyl group having 1 to 9 carbon atoms, or 2 to 6 carbon atoms, or 3 to 5 carbon atoms. Non-limiting examples of cyanoalkyl groups include cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 1-cyanopropyl group, 2-cyanopropyl group, 3-cyanopropyl group, 1-cyanobutyl group, 2-cyanobutyl group, 3-cyanobutyl group, 4-cyanobutyl group, 5-cyanopentyl group, 6-cyanohexyl group, and combinations thereof. In some embodiments, R ２ This may be at least one selected from the group consisting of 2-cyanobutyl groups, 3-cyanobutyl groups, and 4-cyanobutyl groups, and may be a 3-cyanobutyl group.

[0018] In the above formula (I), the subscript x represents the amount of (R) contained in one molecule of (A) cyano group-containing polysiloxane. １ ２ SiO ２／２ ) is the average number of units, and as mentioned above, it is between 0.0 and 50.0. In some embodiments, x may be 1.0 or more, or 3.0 or more, or 4.5 or more, or 7.0 or more, or 9.0 or more, or 11.0 or more. At the same time, x may be 40.0 or less, or 30.0 or less, or 25.0 or less, or 20.0 or less. In some embodiments, x may be between 1.0 and 40.0, or 1.0 and 30.0, or 1.0 and 25.0, or 3.0 and 25.0, or 4.5 and 20.0, or 7.0 and 40.0, or 9.0 and 30.0, or 11.0 and 25.0.

[0019] In the above formula (I), the subscript y represents the amount of (R) contained in one molecule of (A) cyano group-containing polysiloxane. １ R ２ SiO ２／２) is the average number of units, and as mentioned above, is between 1.0 and 100.0. In some embodiments, y may be 2.0 or more, or 3.0 or more, or 4.0 or more, or 5.0 or more. At the same time, y may be 75.0 or less, or 50.0 or less, or 40.0 or less, or 30.0 or less, or 20.0 or less. In some embodiments, y may be between 2.0 and 75.0, or 3.0 and 50.0, or 4.0 and 40.0, or 5.0 and 30.0, or 5.0 and 20.0.

[0020] In the above formula (I), the subscript z represents the amount of (R) contained in one molecule of (A) cyano group-containing polysiloxane. １ HSiO ２／２ ) is the average number of units, and as mentioned above, is between 1.0 and 50.0. In some embodiments, z may be 2.0 or more, or 3.0 or more, or 4.0 or more, and at the same time, z may be 40.0 or less, or 30.0 or less, or 20.0 or less, or 10.0 or less, or 9.0 or less. In some embodiments, it may be between 2.0 and 40.0, or 3.0 and 30.0, or 4.0 and 20.0, or 4.0 and 10.0, or 4.0 and 9.0.

[0021] In some embodiments, the cyano group content in (A) cyano group-containing polysiloxane (hereinafter sometimes referred to as "CN content in component (A)") may be 1.0% by weight or more, or 2.0% by weight or more, or 4.0% by weight or more, or 6.0% by weight or more, on a weight basis of (A) cyano group-containing polysiloxane (i.e., with the weight of (A) cyano group-containing polysiloxane as 100% by weight). At the same time, the cyano group content in component (A) may be 20.0% by weight or less, or 18.0% by weight or less, or 16.0% by weight or less, or 14.0% by weight or less. In some embodiments, the cyano group content in component (A) may be 1.0 to 20.0% by weight, or 2.0 to 18.0% by weight, or 4.0 to 16.0% by weight, or 6.0 to 14.0% by weight.

[0022] In some embodiments, the content of silicon-bonded hydrogen atoms in (A) cyano group-containing polysiloxane may be 0.05% by weight or more, or 0.10% by weight or more, or 0.20% by weight or more, based on the weight of (A) cyano group-containing polysiloxane. At the same time, the content of silicon-bonded hydrogen atoms may be 0.90% by weight or less, or 0.60% by weight or less, or 0.30% by weight or less. In some embodiments, the content of silicon-bonded hydrogen atoms may be 0.05 to 0.90% by weight, or 0.10 to 0.60% by weight, or 0.20 to 0.30% by weight.

[0023] In some embodiments, the number-average molecular weight (Mn) of the cyano group-containing polysiloxane (A) may be 500 or more, or 1,000 or more, or 2,000 or more. At the same time, the number-average molecular weight may be 10,000 or less, or 8,000 or less, or 6,000 or less. In some embodiments, the number-average molecular weight may be 500 to 10,000, or 1,000 to 8,000, or 2,000 to 6,000.

[0024] In some embodiments, the molecular weight distribution (weight-average molecular weight / number-average molecular weight, Mw / Mn) of the cyano group-containing polysiloxane (A) may be 1.10 to 4.00, or 1.40 to 3.00.

[0025] In some embodiments, (A) the kinematic viscosity of the cyano group-containing polysiloxane is 10 mm². ２ It may be 100 mm or more ２ It may be 300 mm or more, and the speed may be 300 mm or more. ２ It may be 1,000 mm or more ２ It may be greater than or equal to / s. Furthermore, the kinematic viscosity may be 10,000 mm ２ It may be less than / s, and 5,000 mm ２ It may be less than / s, and 1,500 mm ２ It may be less than / s, and 1,000 mm ２ It may be less than / s, and 500 mm ２ It may be less than / s, and 200 mm ２It may be less than or equal to / s. In some embodiments, the kinematic viscosity of (A) the cyano group-containing polysiloxane is 10 to 10,000 mm². ２ It may also be / s, and 10 to 1,500 mm ２ It may also be / s, and 10 to 500 mm ２ It may also be / s, and 10-200 mm ２ It may also be / s, and 100 to 10,000 mm ２ It may also be / s, and 100 to 1,500 mm ２ It may also be / s, and 100-500 mm ２ It may also be / s, and 300 to 10,000 mm ２ It may also be / s, and 300 to 1,500 mm ２ It may also be / s, and 300-500 mm ２ It may also be / s, and 1,000 to 10,000 mm ２ / s is also acceptable.

[0026] In some embodiments, the cyano group content in the silicone composition (hereinafter sometimes referred to as "CN content in the composition") may be 2.00% by weight or more, or 3.50% by weight or more, or 5.00% by weight or more, based on the total weight of the silicone composition (i.e., with the total weight of the silicone composition as 100% by weight). At the same time, the CN content in the composition may be 15.00% by weight or less, or 13.00% by weight or less, or 11.00% by weight or less. In some embodiments, the CN content in the composition may be 2.00 to 15.00% by weight, or 3.50 to 13.00% by weight, or 5.00 to 11.00% by weight.

[0027] In some embodiments, the content of (A) cyano group-containing polysiloxane in the silicone composition may be 50.00% by weight or more, or 65.00% by weight or more, or 80.00% by weight or more, based on the total weight of the silicone composition. At the same time, the content of (A) cyano group-containing polysiloxane may be 99.00% by weight or less, or 95.00% by weight or less, or 90.00% by weight or less. In some embodiments, the content of (A) cyano group-containing polysiloxane may be 50.00 to 99.00% by weight, or 65.00 to 95.00% by weight, or 80.00 to 90.00% by weight.

[0028] <(B) Organopolysiloxane> (B) Polysiloxane has two or more alkenyl groups per molecule and can react with the above-mentioned (A) cyano group-containing polysiloxane to form a cured product. (B) Polysiloxane may be used alone or in combination of any selected types.

[0029] Non-exclusive examples of alkenyl groups include vinyl, allyl, isopropenyl, butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, and combinations thereof.

[0030] (B) The number of alkenyl groups contained in one molecule of polysiloxane is two or more, or may be three or more, as described above. At the same time, the number of alkenyl groups may be 100 or less, or 50 or less, or 20 or less, or 10 or less, or 5 or less. In some embodiments, the number of alkenyl groups may be 2 or more and 100 or less, or 2 or more and 50 or less, or 2 or more and 20 or less, or 2 or more and 10 or less, or 3 or more and 10 or less, or 3 or more and 5 or less. In addition, in (B) polysiloxane, the alkenyl groups may be directly bonded to the silicon atoms, or they may be bonded to the silicon atoms via other groups.

[0031] In some embodiments, the number of silicon atoms contained in one molecule of (B) polysiloxane may be 2 or more, or 3 or more, or 4 or more. At the same time, the number of silicon atoms may be 150 or less, or 100 or less, or 50 or less, or 20 or less, or 10 or less, or 5 or less. In some embodiments, the number of silicon atoms may be 2 to 150, or 2 to 100, or 2 to 50, or 2 to 20, or 2 to 10, or 3 to 10, or 4 to 5 or less.

[0032] In some embodiments, the (B) polysiloxane contains silicon atom bonding groups (groups that bond to silicon atoms) that do not contain alkenyl groups. Non-limiting examples of such silicon atom bonding groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, phenyl, tolyl, xylyl, naphthyl, and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine and / or cyano groups, as well as combinations thereof. In some embodiments, the (B) polysiloxane may not contain halogen atoms.

[0033] In some embodiments, (B) polysiloxane may not have a cyano group.

[0034] (B) Polysiloxane may include linear, branched, cyclic, resinous (i.e., having a three-dimensional network), or combinations of different structures. For example, (B) polysiloxane may include any combination of M-type, D-type, T-type, and / or Q-type siloxane units. By combining these siloxane units in various ways, linear, branched, cyclic, and / or resinous (B) polysiloxanes can be formed. In some embodiments, (B) polysiloxane may be cyclic.

[0035] (B) Non-limiting examples of polysiloxanes include dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylpolysiloxane with diphenylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylphenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / diphenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylphenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, and dimethylvinylsiloxy groups sealed at both ends of the molecular chain. Examples include methylsiloxane / methylphenylsiloxane / methylvinylsiloxane copolymers, dimethylsiloxane / diphenylsiloxane / methylvinylsiloxane copolymers with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, methylvinylpolysiloxane with trimethylsiloxy groups sealed at both ends of the molecular chain, methylvinylsiloxane / methylphenylsiloxane copolymers with trimethylsiloxy groups sealed at both ends of the molecular chain, methylvinylsiloxane / diphenylsiloxane copolymers with trimethylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylvinylsiloxane copolymers with trimethylsiloxy groups sealed at both ends of the molecular chain, vinyl group-containing cyclic siloxanes, and combinations thereof.

[0036] In some embodiments, the kinematic viscosity of (B) polysiloxane is 0.5 mm ２ It may be more than / s, and 1 mm ２ It may be 2 mm or more ２ It may be 1 / s or more. At the same time, the viscosity of the (B) polysiloxane is 500 mm ２ It may be less than / s, and 300 mm ２ It may be less than / s, and 100 mm ２ It may be less than / s, and 50 mm ２ It may be less than or equal to / s. In some embodiments, the viscosity of the (B) polysiloxane is 0.5 to 500 mm ２ It may also be / s, and 0.5 to 300 mm ２ It may also be / s, and 1 to 100 mm ２It may also be / s, and 2 to 50 mm ２ / s is also acceptable.

[0037] In some embodiments, the content of (B) polysiloxane in the silicone composition may be 0.50% by weight or more, or 2.00% by weight or more, or 6.00% by weight or more, or 10.00% by weight or more, based on the total weight of the silicone composition. At the same time, the content of (B) polysiloxane may be 35.00% by weight or less, or 30.00% by weight or less, or 25.00% by weight or less, or 20.00% by weight or less. In some embodiments, the content of (B) polysiloxane may be 0.50 to 35.00% by weight, or 2.00 to 30.00% by weight, or 6.00 to 25.00% by weight, or 10.00 to 20.00% by weight.

[0038] In some embodiments, the total content of (A) cyano group-containing polysiloxane and (B) polysiloxane in the silicone composition may be 60.00 to 99.95% by weight, or 70.00 to 99.95% by weight, or 80.00 to 99.95% by weight, or 90.00 to 99.95% by weight, or 95.00 to 99.90% by weight, based on the total weight of the silicone composition.

[0039] <(C) Curing Catalyst> The (C) curing catalyst is not particularly limited as long as it is a substance that can promote the hydrosilylation reaction between the (A) cyano group-containing polysiloxane and the (B) polysiloxane. For example, the (C) curing catalyst can be a photocuring catalyst, a thermocuring catalyst, or a combination thereof. The (C) curing catalyst may be used alone or in combination of two or more types.

[0040] The photocuring catalyst is not particularly limited as long as it is a substance that can promote the hydrosilylation reaction between (A) the cyano group-containing polysiloxane and (B) the polysiloxane by irradiation with electromagnetic waves such as light or electron beams. Non-limiting examples of photocuring catalysts include cyclopentadienyl platinum complexes, cyclooctadienyl platinum complexes, platinum(II)-β-diketnate complexes, and combinations thereof.

[0041] Non-limiting examples of cyclopentadienyl platinum complexes include η5-cyclopentadienyl)tri(α-alkyl)platinum(IV), cyclopentadienyltrimethylplatinum(IV), and trimethyl(methylcyclopentadienyl)platinum(IV). Non-limiting examples of cyclooctadienyl platinum complexes include η4-1,5-cyclooctadienediarylplatinum complexes. Non-limiting examples of platinum(II)-β-diketnate complexes include bis(acetylacetonate)platinum(II).

[0042] Examples of cyclopentadienyl platinum complexes are known in the art and are disclosed, for example, in U.S. Patent No. 4,510,094 by Drahnak, U.S. Patent No. 4,600,484 by Drahnak, U.S. Patent No. 4,916,169 by Boardman et al., U.S. Patent No. 6,127,446 by Butts, U.S. Patent No. 6,451,869 by Butts, U.S. Patent No. 6,376,569 by Oxman et al., U.S. Patent No. 8,088,878 by Koellnberger, and CN101925608B. Examples of cyclooctadienyl platinum complexes are known in the art and are disclosed, for example, in U.S. Patent No. 6,046,250 by Bordman et al. Examples of platinum(II) β-diketnate catalysts are known in the art and are disclosed, for example, in Oxman et al. EP0398701(B1), Ikeno U.S. Patent No. 8,642,674, and CN104031602A.

[0043] The thermosetting catalyst is not particularly limited as long as it is a substance that can promote the hydrosilylation reaction between (A) the cyano group-containing polysiloxane and (B) the polysiloxane upon heating. Non-limiting examples of thermosetting catalysts include platinum group metal catalysts, peroxide catalysts, and combinations thereof.

[0044] The platinum group metal catalyst may be at least one platinum group metal selected from the group consisting of platinum, rhodium, ruthenium, palladium, osmium, and iridium, or a platinum group metal selected from the group consisting of platinum, ruthenium, and iridium, or platinum. The platinum group metal catalyst may be a compound containing the above-mentioned platinum group metals, for example, a rhodium diphosphine chelate such as chloride tris(triphenylphosphane)rhodium(I) (Wilkinson catalyst), [1,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2-bis(diethylphosphino))ethane]dichlorodirhodium, chlorplatinic acid (Spier catalyst), chlorplatinic acid hexahydrate, or platinum dichloride. The platinum group metal catalyst may be a complex of the aforementioned platinum group metal with an alkenyl-functional organopolysiloxane oligomer, or a platinum group metal microencapsulated in a matrix or core-shell structure. An example of such a complex is the platinum complex of 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane (Karstedt catalyst). The platinum group metal catalyst may also contain the above complex microencapsulated in a resin matrix. These platinum group metal catalysts may be used individually or in combination of two or more types.

[0045] Non-limiting examples of peroxide catalysts include benzoyl peroxide, tert-butyl perbenzoate, orthomethylbenzoyl peroxide, paramethylbenzoyl peroxide, ditert-butyl peroxide, dicumyl peroxide, 1,1-bis(tert-butyl peroxy)3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexine, and combinations thereof.

[0046] In some embodiments, the (C) curing catalyst in the silicone composition may include a platinum-containing catalyst (for example, the catalysts exemplified as the photocuring catalyst and thermocuring catalyst described above). The content of the (C) curing catalyst in the silicone composition depends on various factors such as the selection of components (A), (B), and (C) described above, the content of alkenyl groups in the silicone composition, and the proportion of silicon-bonded hydrogen atoms. For example, in embodiments where a platinum-containing catalyst is used as the (C) curing catalyst, the content of the (C) curing catalyst may be such that the amount of platinum is 1 to 6,000 ppm by weight, or 1 to 5,200 ppm by weight, or 1 to 1,000 ppm by weight, or 1 to 100 ppm by weight, based on the total weight of the silicone composition. In some embodiments, the content of the (C) curing catalyst may be 0.01 to 5.00% by weight, based on the total weight of the silicone composition.

[0047] <Other Components> The other components that the silicone composition may optionally include are not particularly limited. Non-limiting examples of other components include (D) organohydrogenpolysiloxanes (crosslinking agents, chain length extenders) having two or more silicon-bonded hydrogen atoms per molecule and not having alkenyl groups or cyano groups, (E) adhesion promoters, (F) fillers, and (G) curing inhibitors, as well as combinations thereof. These components (D) to (G) are not particularly limited, and known components can be used.

[0048] In some embodiments, the content of other components in the silicone composition may be 0.00 to 30.00% by weight, or 0.00 to 20.00% by weight, or 0.00 to 10.00% by weight, based on the total weight of the silicone composition.

[0049] <Preparation of Silicone Composition> The method for preparing the silicone composition is not particularly limited. A silicone composition can be obtained by mixing the above-mentioned components using known methods. In some embodiments, vinyl groups (CH) in the silicone composition are used. ２ The ratio of the total number of moles of silicon-bonded hydrogen atoms to the total number of moles of (=CH-) (hereinafter sometimes abbreviated as "SiH / Vi") may be 0.90 to 1.50, or 1.00 to 1.40, or 1.10 to 1.30.

[0050] (Cured product) This disclosure provides a cured product obtained by curing the above-described silicone composition. In some embodiments, the cured product may exhibit excellent chemical resistance.

[0051] The curing method for obtaining curing from a silicone composition is not particularly limited and includes light irradiation, heating, and combinations thereof. The curing conditions are also not particularly limited. When curing is performed by ultraviolet irradiation (light irradiation), known lamps such as high-pressure mercury lamps, medium-pressure mercury lamps, Xe-Hg lamps, and deep UV lamps can be used as ultraviolet sources. In addition, the amount of ultraviolet irradiation is not particularly limited, but for example, 100 to 8,000 mJ / cm². ２ It can be within this range. When curing by heating, the heating conditions during curing may be 70 to 200°C for 10 minutes to 5 hours. Furthermore, after the above ultraviolet irradiation and / or heating, the cured product may be cured as needed.

[0052] The applications of the silicone compositions and cured products of this disclosure described above are not particularly limited. In some embodiments, the cured products of this disclosure have advantages such as excellent chemical resistance and poor swelling and dissolution in organic solvents such as toluene. Therefore, the silicone compositions and cured products of this disclosure can be used in any application where chemical resistance is required. Non-limiting examples of such applications include protective agents used in electronic devices such as sensors. Conventionally, perfluoroalkyl substances (PFAS) have been widely used in applications where chemical resistance is required. However, PFAS have a heavy burden on the environment, and in recent years there has been a demand for alternative materials. Under these circumstances, the silicone compositions and cured products of this disclosure are useful as chemically resistant materials that can replace PFAS.

[0053] The silicone compositions and cured products of this disclosure will be further described below based on examples, but this disclosure is not limited to the following examples.

[0054] <Chemical Resistance 1: Swelling Degree> A silicone composition coating film measuring 20 mm in width, 30 mm in length, and 2 mm in thickness was pressed and mold-cured at 150°C for 30 minutes, and then heated in an oven at 150°C for another 30 minutes to obtain a cured product. A circular sample with a diameter of 8 mm and a thickness of 2 mm was cut from the obtained cured product, and the weight W0 of this circular sample was measured. Next, this circular sample was immersed in 10 g of toluene at room temperature (25°C) for 120 hours. After immersion, excess toluene adhering to the surface of the circular sample was wiped off, and the weight W1 of the sample was immediately measured, and the weight increase rate (weight %) = (W1 - W0) / W0 × 100 was calculated. This operation was performed at least twice in total for each example and comparative example, and the average value of the weight increase rate (swelling degree) was calculated. The smaller the value of this swelling degree, the better the chemical resistance of the cured product. <Chemical Resistance 2: Toluene Absorption> A silicone composition coating with dimensions of 20 mm width x 30 mm length x 2 mm thickness was pressed and mold-cured at 150°C for 30 minutes, and then heated in an oven at 150°C for another 30 minutes to obtain a cured product. A circular sample with a diameter of 8 mm and a thickness of 2 mm was cut from the obtained cured product, and the weight w0 of this circular sample was measured. Next, this circular sample was immersed in 10 g of toluene at room temperature (25°C) for 120 hours. After immersion, excess toluene adhering to the surface of the circular sample was wiped off, and the weight w1 of the sample was immediately measured. Subsequently, the circular sample was heated under vacuum at 50°C for 5 hours to remove the toluene absorbed inside the circular sample. The weight w2 of the circular sample after this operation was measured. The amount extracted from the circular sample into toluene (the amount of cured product eluted from the circular sample into toluene) w3 = w0 - w2 was calculated for Examples 1-2 and Comparative Example 1. The value of the extracted amount w3 was approximately 10% by weight relative to w0 in all cases. Next, the amount of toluene absorbed into the circular sample, w4 = (w1 + w3) - w0, was calculated. This procedure was performed at least twice in total for each example and comparative example, and the average value of the amount of toluene absorbed into the circular sample (i.e., the cured product) (toluene absorption amount) was calculated. The smaller this toluene absorption amount, the better the chemical resistance of the cured product. <Storage modulus> For dynamic viscoelasticity measurement (DMA), an Anton Paar MCR302 was used. Circular samples were prepared using the same procedure as for "chemical resistance" above.This circular sample was clamped between an upper parallel plate and a lower Peltier plate (connected to MCR302) with a normal force of 0.5 N. The measurement temperature was set to 23°C, the shear strain amplitude to 0.2%, and the vibration frequency was varied from 0.01 Hz to 10 Hz, and the storage modulus (Pa) at 0.1 Hz was recorded. This storage modulus serves as an indicator of the degree of hardening (crosslinking) in the hardened material.

[0055] <Production Example 1: (A1) Cyano Group-Containing Polysiloxane> -Preparation of Prepolymer- 50 g of hydrochloric acid (35-37% by weight), 150 g of deionized water, and 150 g of toluene were added to a 1-liter glass reactor equipped with a stirrer, reflux condenser, thermometer, and dropping funnel. To this mixture in the reactor, 150 g of 3-cyanobutylmethyldimethoxysilane was added dropwise over 0.5 hours at room temperature using a dropping funnel while stirring. Then, the hydrolysis reaction was carried out for 2 hours while maintaining the room temperature at 25-35°C (see chemical reaction below). After cooling, the aqueous layer was removed by liquid-liquid separation, and the organic layer was washed three times with 200 g of water. Next, it was neutralized with 220 g of a 20% by weight sodium bicarbonate aqueous solution. After further washing twice with 200 g of water, it was dried with sodium sulfate. Toluene was removed from the organic layer under reduced pressure to obtain 102 g of prepolymer.

[0056] - (A1) Synthesis of cyano group-containing polysiloxane - 48.78 g of the above prepolymer, 10.30 g of tetramethylcyclotetrasiloxane, 12.62 g of octamethylcyclotetrasiloxane, and 3.79 g of hexamethyldisiloxane were added to a 0.2 liter glass reactor equipped with a stirrer, reflux condenser, and thermometer. To the mixture in the reactor, 0.05 g of trifluoromethanesulfonic acid and 5 μL of deionized water were added under stirring, and the reaction was carried out at room temperature for 6 hours (see chemical reaction below). After the reaction, the mixture was neutralized with 0.014 g of ammonia gas, the neutralized salt was removed by filtration, and then the low-siloxane component was removed from the filtrate under reduced pressure to obtain 57.35 g of (A1) polysiloxane.

[0057] <Production Example 2: (A2) Cyano Group-Containing Polysiloxane> A prepolymer was prepared in the same manner as in Production Example 1. Then, 83.92 g of (A2) polysiloxane was obtained in the same manner as in Production Example 1, except that the amount of prepolymer was 36.96 g, the amount of tetramethylcyclotetrasiloxane was 38.81 g, the amount of octamethylcyclotetrasiloxane was 15.73 g, and the amount of hexamethyldisiloxane was 8.50 g.

[0058] The properties of the (A1) to (A2) cyano group-containing polysiloxanes obtained above are shown in Table 1 below.

[0059]

[0060] Table 2 below shows the components other than the polysiloxanes (A1) and (A2) used in the examples and comparative examples. All of these components are available from Dow Chemical Company.

[0061]

[0062] <Examples 1-2 and Comparative Example 1> Silicone compositions were prepared by mixing the components listed in Tables 1 and 2 above in the proportions (weight %) shown in Table 3. The chemical resistance 1 and 2 (swelling degree and toluene absorption) and storage modulus of the cured product were evaluated using the obtained silicone compositions. The results are shown in Table 3.

[0063]

[0064] Comparing the results of Examples 1 and 2 with those of Comparative Example 1, it can be seen that while they have similar storage moduli and degrees of hardening, the cured products of Examples 1 and 2 exhibit superior chemical resistance compared to the cured product of Comparative Example 1.

[0065] This disclosure provides silicone compositions and cured products obtained by curing the silicone compositions. In some embodiments disclosed herein, cured products with excellent chemical resistance and silicone compositions capable of forming such cured products are provided.

Claims

1. (A) Formula (I) below: [In the above formula (I), R １ Each of these is independently an alkyl group or an aromatic hydrocarbon group, and R ２ A cyano group-containing organohydrogenpolysiloxane represented by (A) a cyanoalkyl group, where x is 0.0 to 50.0, y is 1.0 to 100.0, and z is 1.0 to 50.0; (B) an organopolysiloxane having two or more alkenyl groups per molecule; and (C) a curing catalyst, comprising a silicone composition.

2. The silicone composition according to claim 1, wherein the content of the cyano group-containing organohydrogenpolysiloxane (A) is 50.00% by weight or more and 99.00% by weight or less based on the total weight of the silicone composition.

3. The silicone composition according to claim 1, wherein the cyano group content is 2.00% by weight or more and 15.00% by weight or less based on the total weight of the silicone composition.

4. The aforementioned R ２ The silicone composition according to claim 1, wherein is a cyanoalkyl group having 2 to 6 carbon atoms.

5. The aforementioned R ２ The silicone composition according to claim 1, wherein is a 3-cyanobutyl group.

6. The kinematic viscosity of the organopolysiloxane (B) is 0.5 mm ２ / s or more 500mm ２ The silicone composition according to claim 1, wherein the value is less than or equal to / s.

7. The silicone composition according to claim 1, wherein the number of silicon atoms contained in one molecule of the organopolysiloxane (B) is 2 or more and 150 or less.

8. The silicone composition according to claim 1, wherein the (B) organopolysiloxane does not have a cyano group.

9. The silicone composition according to claim 1, wherein the content of (B) organopolysiloxane is 0.50% by weight or more and 35.00% by weight or less based on the total weight of the silicone composition.

10. The silicone composition according to claim 1, wherein the sum of the content of (A) cyano group-containing organohydrogenpolysiloxane and the content of (B) organopolysiloxane is 60.00% by weight or more and 99.95% by weight or less based on the total weight of the silicone composition.

11. A cured product obtained by curing a silicone composition according to any one of claims 1 to 10.

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