Room-temperature-curable silicone composition

Abstract

To provide a moisture-curable silicone composition which can achieve both sufficient adhesiveness and compression set at low temperatures and in a short time in various sealants and potting agents for automotive industrial products or the like in which high reliability is required.SOLUTION: There is provided a moisture-curable silicone composition which comprises (A) a polyorganosiloxane having two or more hydroxyl groups or hydrolyzable groups in one molecule, (B) a siloxane having two or more -OR2 groups bonded to a silicon atom, (C) a condensation catalyst, (D) a silicon-based adhesiveness-imparting agent which is a compound having in one molecule one or more groups selected from the group consisting of an aromatic hydrocarbon-containing group, an epoxy group-containing group and a linear, branched-chain or cyclic aliphatic unsaturated hydrocarbon group and having at least one or more heteroatoms in one molecule other than the adhesiveness-imparting functional group and (E) an inorganic filler.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a room temperature curable silicone composition that is particularly useful as an adhesive. [Background technology]

[0002] Curable polyorganosiloxane compositions that exhibit fluidity in an uncured state and form a rubber-like elastomer (silicone rubber) upon curing are known as materials with excellent heat resistance, cold resistance, weather resistance, and electrical insulation. Curable polyorganosiloxane compositions are used in various industrial fields for parts such as O-rings, packings, and gaskets, and as adhesives between substrates. In particular, there is an increasing demand for bonding metals such as aluminum and aluminum die casting, and engineering plastics such as PBT and PET with silicone. In response to these demands, silicone resin compositions to which sulfur-based compounds have been added have been proposed to improve adhesion to substrates and compression set (Patent Documents 1 and 2).

[0003] Curable silicone compositions are classified into addition reaction type and condensation reaction type according to the curing mechanism. The addition reaction type can be cured in a short time by heating, and has the characteristic of excellent curing properties even in areas where the supply of moisture in the air is insufficient. The condensation reaction type requires a long time to cure, but has the characteristic of curing at room temperature and exhibiting good adhesive properties. Room temperature curing silicone compositions do not require a lot of energy for curing conditions, so they function as adhesives that are suitable for recent changes in environmental awareness. In condensation reaction type (room temperature) curable polyorganosiloxane compositions, there have been proposed curable polyorganosiloxane compositions in which the fluidity, non-sag properties, extrusion properties, adhesive properties, and adhesive durability are improved by blending additives such as fillers and light stabilizers (e.g., Patent Documents 3 and 4).

[0004] Attempts have been made to use curable silicone compositions to bond metal components, but moisture-curable silicone compositions use titanium as a curing catalyst, which does not provide very good adhesion to metals or engineering plastics, and so an adhesion promoter that does not inhibit the titanium catalyst is usually used in combination (Patent Document 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-27997 A [Patent Document 2] Special Publication No. 2018-505917 [Patent Document 3] JP 2001-152020 A [Patent Document 4] JP 2002-302606 A [Patent Document 5] Japanese Patent Publication No. 54-090350 Summary of the Invention [Problem to be solved by the invention]

[0006] When a sealant or adhesive made of a silicone rubber composition is applied to metal, the durability of the adhesive is measured from the viewpoint of water resistance by tests such as salt spray tests and water immersion tests. In particular, in automotive applications, the adhesive part is often exposed to wind and rain, as well as harsh environments accompanied by heating. Furthermore, in automotive applications, contact with oil at the adhesive part is also possible. Therefore, it is necessary for the adhesive to have water and oil resistance to increase its reliability. It is desirable to be able to maintain adhesion for a long period of time, such as several years. However, existing products do not yet have sufficient water and oil resistance. In addition, it is known that conventionally used adhesion promoters such as aminosilanes couple with condensation catalysts, and when the catalyst is a Group IV metal atom such as titanium, this significantly reduces the curing property and ultimately the adhesion.

[0007] An object of the present invention is to provide a moisture-curable silicone composition that has high adhesive properties and also has excellent resistance to water, salt water, and oil. [Means for solving the problem]

[0008] The present inventors have conducted research and found that a silicone composition that can solve the above-mentioned problems can be obtained by using, in combination with an adhesive aid, a hydrolyzable compound that has a cyclic structure, in particular an aromatic ring or heterocycle, and that contains a thioether bond, which has been used in the compound. This led to the completion of the present invention. Effect of the Invention

[0009] The present invention provides a moisture-curable silicone composition that has high adhesiveness and excellent resistance to water, salt water, and oil. That is, the present invention relates to the following [1] to [6]. [1] (A) a polyorganosiloxane having two or more hydroxyl groups or hydrolyzable groups bonded to silicon atoms in each molecule; (B) -OR bonded to silicon atom 2 Group (where R 2 each occurrence of each independently represents a hydrogen atom or a monovalent organic group) in one molecule; (C) Condensation catalyst; (D) silicon-based adhesion promoters (excluding those falling under (A) or (B) above) which are compounds having in one molecule one or more adhesion-imparting functional groups selected from the group consisting of aromatic hydrocarbon-containing groups, epoxy group-containing groups, and linear, branched, or cyclic aliphatic unsaturated hydrocarbon groups, and which have in one molecule at least one heteroatom other than the adhesion-imparting functional groups; and (E) Inorganic filler and the content of the component (D) is 0.05 to 20 parts by mass per 100 parts by mass of the component (A). [2] The moisture-curable silicone composition according to [1] above, wherein the component (D) is at least one compound selected from the group consisting of sulfur compounds, nitrogen compounds, and phosphorus compounds. [3] The component (D) is SiR 5 3-n (OR 5 ) n Group (where R 5 is a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and n is 1, 2, or 3), and / or a partial hydrolysis condensate thereof. [4] The moisture-curable silicone composition according to [3] above, wherein the component (D) further has one or more groups selected from the group consisting of an aromatic hydrocarbon-containing group, an epoxy group-containing group, and an aliphatic unsaturated hydrocarbon group. [5] (A) component has R at both ends a 3-m R 3 m SiO 1 / 2 Blocked in units, intermediate unit is R 3 2SiO 2 / 2 The unit is a linear polyorganosiloxane (where R a is a hydroxyl group or a hydrolyzable group, R 3 is a hydrogen atom or a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and m is 0, 1, or 2. [6] The component (B) is represented by the following formula: R 1 n Si(OR 2 ) 4-n (In the formula, R 1 is independently in each occurrence a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms; R 2wherein each occurrence independently represents a hydrogen atom or an alkyl or alkenyl group having 1 to 12 carbon atoms (wherein R' is an alkyl group having 1 to 6 carbon atoms and may form a ring together with a carbon portion of the alkyl or alkenyl group), which optionally has a -C(=O)-, -NR'-, or -N=C(R')- group at a terminal and one or more hydrogen atoms are optionally substituted with a halogen or an alkoxy group, and n is 0, 1, or 2), or a partial hydrolysis condensate thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] As described above, the present invention relates to a polyorganosiloxane having, in one molecule, two or more hydroxyl groups or hydrolyzable groups bonded to silicon atoms; 2 Group (where R 2 is independently a hydrogen atom or a monovalent organic group in each occurrence) in one molecule; (C) a condensation catalyst; (D) a silicon-based adhesion promoter (excluding those corresponding to (A) or (B) above) which is a compound having one or more adhesion-imparting functional groups selected from the group consisting of an aromatic hydrocarbon-containing group, an epoxy group-containing group, and a linear, branched, or cyclic aliphatic unsaturated hydrocarbon group in one molecule, and having at least one heteroatom in one molecule other than the adhesion-imparting functional groups; and (E) an inorganic filler, the content of the (D) component being 0.05 to 20 parts by mass relative to 100 parts by mass of the (A) component. Hereinafter, the composition of the present invention will be described in detail for each item. In this specification, the term "to" indicating a numerical range is used to mean that the numerical values ​​before and after it are included as the lower and upper limits.

[0011] As used herein, "organic group" refers to a group containing carbon. The valence of an organic group is indicated by describing it as "n-valent", where n is any natural number. Thus, for example, a "monovalent organic group" refers to a carbon-containing group having only one bond. The bond may be possessed by an element other than carbon. Even if the valence is not specifically stated, a person skilled in the art can grasp the appropriate valence from the context.

[0012] As used herein, the term "hydrocarbon group" refers to a group containing carbon and hydrogen, with at least one hydrogen atom being removed from the molecule. Such a hydrocarbon group is not particularly limited, and examples thereof include a hydrocarbon group having 1 to 20 carbon atoms, which may be substituted with one or more substituents, such as an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The above-mentioned "aliphatic hydrocarbon group" may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The hydrocarbon group may have one or more heteroatoms or structures containing heteroatoms, such as nitrogen atoms (N), oxygen atoms (O), sulfur atoms (S), phosphorus atoms (P), silicon atoms (Si), amide bonds, sulfonyl bonds, siloxane bonds, carbonyl groups, and carbonyloxy groups, at its terminals or in the molecular chain.

[0013] As used herein, examples of the substituents of the "hydrocarbon group" include, but are not limited to, halogen atoms; C 1-6 Alkyl group, C 2-6 Alkenyl group, C 2-6 Alkynyl group, C 3-10 Cycloalkyl groups, C 3-10 Unsaturated cycloalkyl groups, 5-10 membered heterocyclyl groups, 5-10 membered unsaturated heterocyclyl groups, C 6-10 Examples of the group include groups selected from aryl groups and 5- to 10-membered heteroaryl groups.

[0014] In this specification, alkyl groups and phenyl groups may be unsubstituted or substituted unless otherwise specified. Substituents for such groups are not particularly limited, but include, for example, halogen atoms, C 1-6 Alkyl group, C 2-6 Alkenyl groups and C 2-6 alkynyl groups.

[0015] Ingredient (A) The curable polyorganosiloxane composition of the present invention contains, as component (A), at least one polyorganosiloxane having two or more hydroxyl groups or hydrolyzable groups bonded to silicon atoms in one molecule. Component (A) functions as a base polymer of the curable polyorganosiloxane composition. The hydroxyl group or hydrolyzable group can be present at any position of the polyorganosiloxane molecule. For example, the hydroxyl group or hydrolyzable group may be present at a molecular end, or may be present as a side chain at a site other than the end. In the case of a linear polyorganosiloxane, at least one hydroxyl group or hydrolyzable group is preferably present at each end of the molecular main chain of component (A). Here, in this specification, the molecular main chain of component (A) refers to the relatively longest bond chain in the molecule of component (A).

[0016] The term "hydrolyzable group" refers to a group that can undergo hydrolysis, that is, a group that can be removed from the main skeleton of a compound by hydrolysis. Examples of hydrolyzable groups include -OR', -OCOR', -ON=CR'2, -NR'2, -NHR', and halogen atoms (wherein R' represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms), and preferably -OR' (i.e., an alkoxy group). Examples of R' include unsubstituted alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, and isobutyl; and substituted alkyl groups such as chloromethyl. Among them, alkyl groups, particularly unsubstituted alkyl groups, are preferred, and methyl or ethyl groups are more preferred. The hydroxyl group is not particularly limited, and may be one that is generated by hydrolysis of a hydrolyzable group. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, and among these, chlorine atoms are preferred.

[0017] The molecular skeleton of component (A) is not particularly limited as long as the siloxane bond is the main skeleton. The siloxane skeleton may be interrupted by a divalent organic group. Herein, in explaining the structure of the siloxane compound in this specification, the structural units of the siloxane compound may be described by the following abbreviations. Hereinafter, these structural units may be referred to as "M unit", "D unit", etc. M: -Si(CH3)3O 1 / 2 D: Si(CH3)2O 2 / 2 T: Si(CH3)O 3 / 2 Q:SiO 4 / 2 Hereinafter, in this specification, the siloxane compound is constructed by combining the above structural units, but may at least partially contain those in which the methyl groups of the above structural units are replaced with other groups, such as halogens such as fluorine, or hydrocarbon groups such as phenyl groups. In this case, to indicate a state of being replaced with a substituent, the D unit replaced with a phenyl group is referred to as D. Ph For example, D Ph20 D 20 When written as D, the notation is intended to include a total of 20 phenyl groups in the 40 D units. Ph It is not intended that 20 units be followed by 20 D units. Each unit may be arranged in any order, and that SiPh2O 2 / 2 (D Ph2 It is understood that the siloxane compound may contain structural units such as those represented by the following formula: (hereinafter, the formula is expressed as follows): The siloxane compound can have various three-dimensional structures due to the T unit or Q unit, but the component (A) can have a linear molecular skeleton formed by any combination of the above M and D units.

[0018] In one embodiment of the present invention, component (A) is a compound having an average of two or more hydroxyl groups or hydrolyzable groups bonded to silicon atoms in one molecule, and containing the -OR group of (B) described below. 2 There are no particular limitations on the component (A) as long as it is capable of forming a network structure by a condensation reaction with a group. (R a ) s (R 3 ) t SiO (4-s-t) / 2 (1) (In the formula, R a is a hydroxyl group or a hydrolyzable group; R 3 is a monovalent hydrocarbon group having no aliphatic unsaturated bonds; s is an integer from 1 to 3; t is an integer of 0 to 2, with the proviso that s+t is 1 to 3. The molecule has at least two units represented by the following formula:

[0019] A specific example of the component (A) is a compound represented by the following general formula (2): (R a ) 3-p R p Si-O-(Si(R) r (R a ) 2-r O) n -SiRq (R a ) 3-q (2) (In the formula, R a are each independently a hydroxyl group or a hydrolyzable group, Each R is independently a monovalent organic group, p and q are each independently 0, 1 or 2; Each r is independently 0, 1, or 2; n is a number that gives a viscosity of 0.1 to 500 Pa s at 23°C. Examples of the polyorganosiloxane include linear polyorganosiloxanes represented by the formula (2) below. R is preferably a hydrocarbon group, particularly an alkyl group, an alkenyl group, or an aryl group. From the viewpoint of controlling physical properties such as the refractive index, at least a part of R may be an aryl group such as a phenyl group. Polyorganosiloxanes in which all R are methyl are particularly preferably used because of their ease of availability. Regarding the position of the curable functional group, polyorganosiloxanes in which r is 2 in the above formula (2), that is, linear polyorganosiloxanes in which at least one curable functional group exists only at each of both ends of the molecule, are preferred. As such component (A), polyorganosiloxanes in which both ends are R a 3-m R 3 m SiO 1 / 2 Blocked in units, intermediate unit is R 3 2SiO 2 / 2 The unit is a linear polyorganosiloxane (where R a is a hydroxyl group or a hydrolyzable group, R 3 is a monovalent hydrocarbon group, and m is 0, 1 or 2).

[0020] As the polyorganosiloxane having a hydroxyl group or a hydrolyzable group bonded to a silicon atom, it is preferable that p and q are 0 or 1 in the above formula (2), that is, that each has two or more hydroxyl groups or hydrolyzable groups at the molecular end. Such polyorganosiloxanes usable as component (A) can be commercially available. Polyorganosiloxanes into which hydroxyl groups or hydrolyzable groups have been introduced by known reactions may also be used. As component (A), only one type of compound may be used, or two or more types of compounds may be mixed and used, classified according to the position or type of the substituent, the degree of polymerization, etc. Since component (A) is a polyorganosiloxane, it may be a mixture of polyorganosiloxanes having various degrees of polymerization.

[0021] The amount of component (A) is not particularly limited as long as the curable polyorganosiloxane composition has a viscosity within a range that allows it to be handled. Based on the amount of component (A), the amounts of the other components can be appropriately set within the preferred ranges shown below.

[0022] ·Component (B) The crosslinking agent in the curable composition of the present invention is an -OR bonded to a Si atom. 2 It is a compound having at least two groups or a partial hydrolysis condensate thereof (hereinafter also referred to as "crosslinking agent"), and is a compound that undergoes a crosslinking reaction (condensation reaction) with component (A), specifically, with a hydroxyl group or a hydrolyzable group bonded to a Si atom of component (A). In the formula, R 2 is independently a hydrogen atom or a monovalent organic group in each occurrence, and is preferably a monovalent organic group. The monovalent organic group means a group containing monovalent carbon. Such a monovalent organic group is not particularly limited, but may be a monovalent hydrocarbon group. The hydrocarbon group has the same meaning as above.

[0023] The crosslinking agent is Si-OR 2The crosslinking agent may or may not have a reactive functional group other than the group, but from the viewpoint of crosslinking, it is preferable that the crosslinking agent does not have the reactive functional group. In the present invention, the other reactive functional group refers to a primary amino group, an epoxy group, a (meth)acryloyl group, a (meth)acryloxy group, a mercapto group, an isocyanato group, etc. Hereinafter, the crosslinking agent will be described by dividing it into (B1) a crosslinking agent having no reactive functional group and (B2) a crosslinking agent having a reactive functional group.

[0024] <<(B1) Crosslinking agent having no reactive functional group>> (B1) Examples of crosslinking agents having no reactive functional groups include R 1 n Si(OR 2 ) 4-n (In the formula, R 1 is independently in each occurrence a substituted or unsubstituted monovalent hydrocarbon group; R 2 are each independently a hydrogen atom or a monovalent organic group, and n is 0, 1, or 2.

[0025] R 1 R is preferably, independently in each occurrence, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. 1 Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; alkenyl groups such as vinyl, allyl, propenyl, and butenyl; alkynyl groups such as ethynyl and propynyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, chlorine, and bromine (for example, a chloromethyl group, a bromoethyl group, a chloropropyl group, a trifluoropropyl group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group).

[0026] R 2 are each independently in each occurrence a hydrogen atom or an alkyl or alkenyl group having 1 to 12 carbon atoms (wherein R' is an alkyl group having 1 to 6 carbon atoms which may form a ring together with the carbon portion of the alkyl or alkenyl group) which may optionally have a -C(=O)-, -NR'- or -N=C(R')- group at the terminal and in which one or more hydrogen atoms may be substituted by a halogen or an alkoxy group, specifically, CH3-, C2H5-, C3H7-, CF3CH2-, CH3CO-, CH2=C(CH3)-, CH3CH2C(CH3)=N-, (CH3)2N-, (C2H5)2N-, CH2=C(OC2H5)-, (CH3)2C=C(OC8H 17 )- or [ka] It is preferable that R 2 is more preferably a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, and particularly preferably CH3- or C2H5-.

[0027] It is preferred that n is 1 or 2.

[0028] (B1) The crosslinking agent having no reactive functional group further includes at least one [Si(XOR g3 )(CH3)O] units and sometimes [Si(R g4 )(CH3)O] units, and these units are bonded in a ring. g3 Units including R g4 It is understood that the units containing the above may be arranged in any order, such as alternately existing between the above and the above.

[0029] R g3 is a monovalent organic group, and the specific R g3 is an alkyl group having 1 to 12 carbon atoms, preferably 1 to 4 carbon atoms, -Si(OR") 3-w R” w(wherein R″ is an alkyl group having 1 to 4 carbon atoms, and w is an integer of 0 to 3). g3 Examples of the silyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl groups, trimethoxysilyl, triethoxysilyl, dimethoxymethylsilyl, and diethoxyethylsilyl groups. X is a single bond or a divalent alkylene group having 1 to 12 carbon atoms.

[0030] R g4 R is independently at each occurrence a monovalent organic group. g4 R is preferably a substituted or unsubstituted monovalent hydrocarbon group, and more preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. g4 Specific examples of the alkyl group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, and decyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, and cycloheptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, and naphthyl group; aralkyl groups such as benzyl group, phenylethyl group, and phenylpropyl group; alkenyl groups such as vinyl group, allyl group, propenyl group, and butenyl group; alkynyl groups such as ethynyl group and propynyl group; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, chlorine, and bromine atoms (for example, a chloromethyl group, a bromoethyl group, a chloropropyl group, a trifluoropropyl group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group).

[0031] [Si(XOR g3 The number of [Si(R g4 The number of [Si(XOR g3 When the number of [Si(XOR)(CH3)O] units in one molecule is 1, the number is 1 or more.g3 )(CH3)O] units and [Si(R g4 The total number of the units is preferably 2 or more and 4 or less.

[0032] Preferably, the (B1) crosslinking agent having no reactive functional group is represented by the formula: R 1 n Si(OR 2 ) 4-n (wherein R 1 , R 2 and n is as defined above).

[0033] In a preferred embodiment, the crosslinking agent (B1) having no reactive functional group is an alkoxy group-containing compound such as tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, decyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, dimethyldimethoxysilane, vinylmethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, and 3-chloropropyltrimethoxysilane, and partial hydrolysis condensates thereof; tetrakis(2-ethoxy)silane; substituted alkoxy group-containing compounds such as methyltripropenoxysilane, methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltriisopropenoxysilane, dimethyldiisopropenoxysilane, methylvinyldiisopropenoxysilane, and partial hydrolysis condensation products thereof; enoxy group-containing compounds such as methyltriacetoxysilane and partial hydrolysis condensation products thereof; [ka] Examples of the cyclic siloxane compounds include those represented by the following formula:

[0034] <<(B2) Crosslinking agent having reactive functional group>> The crosslinking agent having a reactive functional group (B2) is a compound that not only contributes to the crosslinking reaction (condensation reaction) with the component (A) but also functions as an adhesion promoter. [ka] It is possible to use a compound represented by the following formula:

[0035] In formula (B2), R g3 and R g4 has the same meaning as above.

[0036] In formula (B2), R g6 each occurrence independently represents R g8 -R g7 - represents.

[0037] R g7 represents, independently at each occurrence, a single bond, an oxygen atom, or a divalent organic group, where the divalent organic group is as defined above.

[0038] R g7 is preferably an alkylene group having 1 to 10 carbon atoms, or a group having 1 to 10 carbon atoms and containing a nitrogen atom or an oxygen atom in the main chain.

[0039] R g7 is more preferably an alkylene group having 1 to 3 carbon atoms; CH2CH2-NH-CH2CH2CH2, or CH2-O-CH2CH2CH2.

[0040] R g8 is a reactive functional group. g8is preferably, each independently at each occurrence, a primary amino group, an epoxy group, a (meth)acryloyl group, a (meth)acryloxy group, a mercapto group, or an isocyanato group, and is more preferably a primary amino group.

[0041] In formula (B2), ε4 is 2 or 3, more preferably 3. In formula (B2), ε5 is 0 or 1. In formula (B2), ε6 is 1 or 2, preferably 1. However, the sum of ε4, ε5 and ε6 is 4. Particularly preferably, ε4 is 3, ε5 is 0 and ε6 is 1.

[0042] (B2) Examples of crosslinking agents having a reactive functional group include substituted or unsubstituted amino group-containing silanes such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropyltriacetamidosilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and N,N-dimethyl-3-aminopropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3, Examples include epoxy group-containing silanes such as 4-epoxycyclohexylethyltrimethoxysilane; isocyanato group-containing silanes such as 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropylmethyldimethoxysilane; (meth)acryloxy group-containing silanes such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane; mercapto group-containing silanes such as 3-mercaptopropyltrimethoxysilane; and mixtures or reaction products of primary amino group-containing silanes and epoxy group-containing silanes.

[0043] The crosslinking agent may be used alone or in combination of two or more. When two or more types are used in combination, it may be two or more types of (B1), two or more types of (B2), or one or more types of each of (B1) and (B2). From the viewpoint of crosslinking property, it is preferable that the crosslinking agent (b) contains at least one type of (B1).

[0044] In addition, as a crosslinking agent, 1 n Si(OR 2 ) 4-n In the case where two or more kinds of alkoxysilanes or the like represented by the formula are contained, it is preferable to use two kinds having different values ​​of n in the above formula in combination. In this case, the smaller the value of n, the more preferable the R 1 and R 2 For example, when a tetrafunctional alkoxysilane or the like in which the value of n is 0 and a trifunctional alkoxysilane or the like in which the value of n is 1 are used, R 1 and R 2 At least one of the R 1 and R 2 The number of carbon atoms in the R 1 and R 2 Both of the carbon numbers are 4 and the R 1 and R 2 It is preferable that the number of carbon atoms is smaller than that.

[0045] The crosslinking agent may be contained in the curable composition in an amount of, for example, 0.1 part by mass or more, specifically 0.3 part by mass or more, and 30 parts by mass or less, specifically 20 parts by mass or less, and more specifically 10 parts by mass or less, relative to 100 parts by mass of component (A).

[0046] The crosslinking agent can be contained in the curable composition in an amount of, for example, 0.1 to 30 parts by mass, specifically, 0.3 to 10 parts by mass, and more specifically, 0.3 to 5.0 parts by mass, relative to 100 parts by mass of component (A).

[0047] The crosslinking agent is, for example, -OR 2 The crosslinking agent may contain 1 mole or more, specifically 2 moles or more, of a hydroxyl group or hydrolyzable group bonded to a Si atom of component (A), for example, -OR 2 The group may include 30 moles or less, specifically 20 moles or less, and more specifically 10 moles or less.

[0048] The crosslinking agent is a -OR 2 The group can be contained in the range of, for example, 1 to 30 mol, specifically, 2 to 20 mol.

[0049] (Condensation catalyst) The (C) condensation catalyst is a component that promotes hydrolysis and condensation between the above-mentioned component (A) and the above-mentioned crosslinking agent. As the condensation catalyst, a metal catalyst, an organic acid catalyst, an inorganic acid catalyst, a base catalyst, etc. can be used. From the viewpoint of the curing speed of the composition, the condensation catalyst is preferably a metal catalyst.

[0050] Examples of the metal atom contained in the metal catalyst include titanium, zirconium, tin, etc. In particular, organotin compounds or alkoxytitaniums are preferred.

[0051] As an embodiment of the metal catalyst, an alkoxide (-OR h When a compound having an alkoxide is used as the metal catalyst, the above R h is preferably an alkyl group having 1 to 4 carbon atoms. When such a catalyst is used, the condensation reaction is further promoted. When a compound having an alkoxide is used as the metal catalyst, the above R hThe catalyst is preferably an alkyl group having 1 to 3 carbon atoms. The use of such a catalyst particularly accelerates the condensation reaction. The catalyst is easily dissolved or dispersed in the curable composition, and can contribute to the promotion of a uniform reaction. The catalyst contains little foreign matter, and can contribute to the formation of a transparent cured product of the curable composition.

[0052] Preferred metal catalysts include metal carboxylates such as iron octoate, manganese octoate, zinc octoate, tin naphthate, tin caprylate, and tin oleate; organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis(triethoxysiloxy)tin, dioctyltin dilaurate, and dimethyltin dineodecanoate; and organotin compounds such as tetraethoxytitanium, tetrapropoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, and diisopropoxytitanium. Examples of the organic titanium compounds include titanium bis(ethylacetoacetate) and 1,3-propanedioxytitanium bis(ethylacetoacetate); aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate, and triethoxyaluminum; and zirconium compounds such as zirconium tetraacetylacetonate, tetraisopropoxyzirconium, tetrapropoxyzirconium, tetra-n-butoxyzirconium, tetraisobutoxyzirconium, tributoxyzirconium acetylacetonate, and tributoxyzirconium stearate.

[0053] Examples of the organic acid catalyst include compounds having a carboxylic acid, a sulfonic acid, or a phosphoric acid. Specific examples of the organic acid catalyst include acetic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid, and alkylphosphoric acid.

[0054] Examples of the inorganic acid catalyst include hydrochloric acid and sulfuric acid.

[0055] Examples of the basic catalyst include ammonia, amine compounds such as triethylamine and diethylamine, dialkylhydroxylamines such as dimethylhydroxylamine and diethylhydroxylamine, tetramethylguanidine, and guanidyl compounds such as guanidyl group-containing silanes or siloxanes.

[0056] The condensation catalyst is preferably contained in an amount of 0.01 to 10.0 parts by mass, and more preferably 0.03 to 5.0 parts by mass, relative to 100 parts by mass of component (A) in the curable composition of the present invention. Only one type of condensation catalyst may be used, or two or more types may be used simultaneously.

[0057] ·Component (D) The composition of the present invention contains a specific adhesion promoter. Specifically, the composition contains a silicon-based adhesion promoter, which is a compound having, in one molecule, at least one adhesion-imparting functional group selected from a linear, branched, or cyclic aliphatic unsaturated hydrocarbon group, an epoxy group, an alkoxy group bonded to a silicon atom, and a hydrogen atom bonded to a silicon atom, and which has, in addition to the adhesion-imparting functional group, at least one heteroatom in one molecule (excluding those falling under (A) or (B)).

[0058] The simplest structure of the compound corresponding to component (D) is a compound in which the above-mentioned adhesive functional group and a functional group having a hetero atom are bonded. Examples of such compounds include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane. However, in consideration of improving adhesion and durability by molecular design, a structure in which an adhesive functional group is bonded to the structure of an organic molecule that is the main skeleton of the compound via a spacer group is a preferred structure. When a heteroatom is present in addition to the main skeleton of the compound, that is, when there is a reactive group of a heteroatom at the end of the molecule, it may couple with a condensation catalyst to affect the curing property, resulting in poor curing. Therefore, a structure in which an adhesive functional group is bonded via a spacer group in the molecular chain is preferred.

[0059] As the main skeleton of the compound corresponding to component (D), it is preferable to use a polyhydric alcohol, an aromatic compound, or a heterocyclic compound, since it is possible to introduce multiple adhesion-imparting functional groups and it is easy to design them to occupy an equivalent positional relationship in the geometric structure of the molecule. In addition, it is preferable that there is a part to which a spacer group can be introduced in a positional relationship that maintains the symmetry of the compound. Since the part to which a spacer group can be introduced can easily introduce a spacer group by a substitution reaction, it is preferable that it has a structure that can form an ether bond or an ester bond, in addition to being able to use halogens or amines. As the structure that can be adopted as the main skeleton, the following are preferred examples, since the raw materials are easily available. [ka]

[0060] The spacer group is a portion that connects the adhesiveness-imparting functional group and the main skeleton. The location of the spacer group in the skeleton is not particularly limited as long as it is in the middle of the molecular chain other than the terminal. It is preferable that a heteroatom exists in the skeleton of this spacer group. As the spacer group, a divalent alkylene group in which at least one position is replaced with a heteroatom is cited as a preferred example because it is easy to design. However, as long as the spacer group is selected so that one heteroatom is introduced in one molecule, a spacer group that does not have a heteroatom, for example, a divalent alkylene group such as ethylene (-CH2-), may be used. From the viewpoint of ensuring sufficient compatibility with silicone such as component (A) and component (B), the divalent alkylene group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 8 carbon atoms. The spacer group may have any structure of a straight chain, a branched chain, or a cyclic structure. In addition, it is preferable that the following adhesiveness-imparting functional group exists at the terminal portion of the spacer group from the viewpoint of molecular design.

[0061] Examples of heteroatoms include oxygen atom (O), nitrogen atom (N), sulfur atom (S), and phosphorus atom (P). These heteroatoms may be contained as structures such as carbonyl, thiocarbonyl, and imine. These heteroatoms are preferably contained as ether structures, thioether structures, amine, or phosphine structures. The compound composed of heteroatoms as component (D) is preferably at least one selected from the group consisting of sulfur compounds, nitrogen compounds, and phosphorus compounds. It is more preferable to have at least one sulfur atom in order to further improve adhesion. When a heteroatom is present in the spacer group, its positional relationship is not particularly limited.

[0062] Component (D) has at least one adhesion-imparting functional group selected from a linear, branched, or cyclic aliphatic unsaturated hydrocarbon group, an epoxy group, an alkoxy group bonded to a silicon atom, and a hydrogen atom bonded to a silicon atom. Although one adhesion-imparting functional group is sufficient to contribute to the impartation of adhesion, it is preferable to have two or more adhesion-imparting functional groups per molecule. It is preferable to have an epoxy group or an alkoxy group bonded to a silicon atom. Component (D) is preferably SiR 5 3-n (OR 5 ) n Group (where R 5 is a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and n is 1, 2, or 3). 5 is particularly preferably a methyl group or an ethyl group. When component (D) is an alkoxysilyl compound having the above group, its partial hydrolysis condensate is also preferred as component (D).

[0063] In addition to the above structure, component (D) may have any organic group. For example, component (D) may further have one or more groups selected from the group consisting of an aromatic hydrocarbon-containing group, an epoxy group-containing group, and an aliphatic unsaturated hydrocarbon group. Specific examples of component (D) include the following compounds, but are not limited thereto as long as they satisfy the above requirements. [ka] TIFF2025032201000006.tif153165

[0064] The content of component (D) is in the range of 0.05 to 20 parts by mass relative to 100 parts by mass of component (A). By setting it in this range, higher adhesion to the substrate can be exhibited. By using 0.05 parts by mass or more, sufficient adhesion can be easily exhibited. In addition, by setting it to 20 parts by mass or less, the concentration of components (A) and (B) in the composition can be kept at an appropriate level, the effect of increasing adhesion can be easily obtained, and the resinification of the surface and the occurrence of cracks can be suppressed to exhibit a more sufficient cured state. A more preferred content range is 0.1 to 15 parts by mass, and even more preferred is a range of 0.5 to 10 parts by mass.

[0065] ·Component (E) The composition of the present invention further contains an inorganic filler to suppress the fluidity of the composition.The inorganic filler includes reinforcing fillers such as fumed titanium oxide; oxides such as silica, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, and aluminum oxide; carbonates such as calcium carbonate, magnesium carbonate, and zinc carbonate; silicates such as aluminosilicate, calcium silicate, and mica; talc; conductive fillers such as carbon black, copper powder, and nickel powder; and those whose surfaces are treated with a hydrophobizing agent.Among these, the inorganic filler is preferably silica, surface-treated silica, carbon black, or calcium carbonate, and more preferably silica or surface-treated silica.

[0066] The curable composition of the present invention particularly preferably contains surface-treated silica as an inorganic filler. By using surface-treated silica, the fluidity of the composition can be suppressed and mechanical strength can be imparted to the cured product of the composition. In this specification, the term "surface treatment" refers to treating silanol groups on the silica surface with a compound that is reactive with the silanol groups of another type of group by covalent bonding.

[0067] Examples of silica include fumed silica, calcined silica, silica aerogel, precipitated silica, and pulverized silica. Among these, fumed silica is preferred because it suppresses the flowability of the composition with a small amount of compounding and imparts mechanical strength to the cured product of the composition. In addition, the surface-treated silica is preferably a silica having a BET specific surface area of ​​50 to 500 m.2 / g is preferable, and 80 to 400m 2 / g is more preferable, and 100 to 300m 2 It is more preferred that the molecular weight is / g.

[0068] Surface treatment methods include silazane compounds (hexamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 1,3-bis(chloromethyl)tetramethyldisilazane, 1,3-bis(3,3,3-trifluoropropyl)-1,1,3,3-tetramethyldisilazane, 1,3-diphenyltetramethyldisilazane, heptamethyldisilazane, 2,2,4,4,6,6-hexamethylcyclotrisilazane, octamethylcyclotetrasilazane, 1,1,3,3-tetramethyldisilazane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane, etc.), alkoxysilane compounds (methyltrimethy Examples of the treatment include treatment with silane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, hexadecyltrimethoxysilane, etc.), chlorosilane compounds (methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, etc.), octamethylcyclotetrasiloxane, dimethylsiloxane oligomers, etc. Among these, chemical treatment with a silazane compound or a chlorosilane compound is preferred because it can hydrophobize the silica surface with a small amount of treatment. In particular, hexamethyldisilazane and dimethyldichlorosilane are preferred. In addition, hexamethyldisilazane is preferred from the viewpoints of the degree of treatment and the stability (inactivation) of the surface state after treatment. The surface treatment agent may be added to the silica during preparation of the curable composition and kneaded to treat the surface of the silica. Alternatively, commercially available materials may be used.

[0069] The inorganic filler preferably has a primary particle diameter of 0.01 to 0.1 μm. By setting the primary particle diameter of the inorganic filler within the above range, a composition with reduced fluidity can be obtained. The primary particle diameter of the inorganic filler is preferably 0.02 to 0.08 μm, and more preferably 0.03 to 0.07 μm. The primary particle diameter is measured by an electron microscope.

[0070] The amount of inorganic filler to be blended may be such that the shape of the curable composition is maintained after application, and is preferably adjusted appropriately within that range. Specifically, the inorganic filler is preferably contained in an amount of 1 to 500 parts by mass, preferably 1 to 200 parts by mass, and more preferably 1 to 100 parts by mass, relative to 100 parts by mass of component (A). In addition, only one type of inorganic filler may be used, or two or more types may be used simultaneously.

[0071] [Curable polyorganosiloxane composition] The curable polyorganosiloxane of the present invention contains the above-mentioned components (A) to (E).

[0072] The polyorganosiloxane composition of the present invention is not particularly limited in its properties as long as each component is uniformly mixed and has a degree of fluidity that allows application to a substrate. The viscosity can be appropriately adjusted by using the resin and solvent described below. The polyorganosiloxane composition can be a one-liquid type composition in which all components are mixed, or a two-liquid type composition in which component (B) and component (C) are mixed separately. The one-liquid type or two-liquid type composition can be appropriately selected in consideration of workability, curing conditions, etc., and the method is known to those skilled in the art.

[0073] The curable polyorganosiloxane composition of the present invention may contain other known components as long as they do not impair the purpose and effect of the composition. As additives, flame retardants, adhesion promoters other than (D), heat resistance promoters, diluents, organic solvents, inorganic or organic pigments, etc. may be appropriately blended. In addition, siloxane resins that do not fall under the above-mentioned components (A) and (B) may also be blended. Examples of such resins include polyorganosiloxanes having only one curable functional group, polyorganosiloxanes having no curable functional group such as dimethylsiloxane, etc. These resins can be used as diluents.

[0074] <Other resins> The curable polyorganosiloxane composition may further contain a siloxane resin that does not fall under the component (A) or (B). Such a resin can also be used as a diluent for adjusting viscosity. Such a siloxane resin is a resin obtained by combining the M, D, T, and Q units, which does not have a hydroxyl group or a hydrolyzable group or has only one of them, particularly a resin represented by the following formula: (R a ) 3-p R p Si-O-(SiRO) n -SiR3 (In the formula, R a , R, p, and n are as defined in general formula (2). and siloxanes having only one hydroxyl group or hydrolyzable group, such as those represented by the following formula: R3Si-O-(SiRO) n -SiR3 (In the formula, R and n are as defined in general formula (2)). It is possible to use a siloxane having no hydroxyl group or hydrolyzable group, which is represented by the following formula: By using such a siloxane resin, it is possible to control the hardness when the curable polyorganosiloxane composition is cured, and to control the viscosity of the composition, and it is possible to widely respond to handling properties and required physical properties.

[0075] Such a resin can be contained in the curable polyorganosiloxane composition in an amount of, for example, 50 parts by mass or less, specifically, 0.1 to 50 parts by mass, and more specifically, 1 to 30 parts by mass, per 100 parts by mass of component (A).

[0076] <Adhesion promoter> The curable polyorganosiloxane composition may further contain an adhesion promoter other than (D). The adhesion promoter is a component that improves the adhesion of the cured product of the composition to substrates such as glass, metal, and plastic. Examples of the adhesion promoter include metal alkoxides, compounds having a hydrolyzable silyl group, compounds having a hydrolyzable silyl group and a reactive organic functional group in one molecule, compounds having a hydrogen atom bonded to a silicon atom and a divalent aromatic group in one molecule, compounds having a hydrogen atom bonded to a silicon atom and a reactive organic functional group in one molecule, and / or partial hydrolysis condensates thereof (excluding those corresponding to (D)). Examples of the metal alkoxide include metal alkoxides such as aluminum alkoxides such as aluminum triethoxide, aluminum tripropoxide, and aluminum tributoxide; titanium alkoxides such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide, and titanium tetraisopropenyl oxide. Examples of organic compound adhesion promoters include amino group-containing silanes, isocyanurates, and carbasilatrane compounds.Specific examples include tetraethoxysilane, tetramethoxysilane oligomers, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3,4-epoxycyclohexylethyltrimethoxysilane.

[0077] The adhesion promoter is, for example, Si(OR 4 ) n Group (where R 4represents an alkyl group having 1 to 4 carbon atoms or a 2-methoxyethyl group; and n is an integer of 1 to 4), and when n is 1 to 3, an organosilicon compound having an epoxy group-containing group and / or a partial hydrolysis condensate thereof are included.

[0078] Specific examples of adhesion promoters other than (D) include aluminum alkoxides such as aluminum triethoxide, aluminum tripropoxide, and aluminum tributoxide; titanium alkoxides such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide, and titanium tetraisopropenyl oxide; zirconium acylates such as zirconium octanoate, zirconium tetra(2-ethylhexanoate), and zirconium stearate; zirconium alkoxides such as n-propyl zirconate and n-butyl zirconate (excluding zirconium chelates); and metal alkoxides such as tributoxy zirconium acetylacetonate, dibutoxy zirconium bis(ethylacetoacetate), zirconium tetraacetylacetonate, zirconium monoacetylacetonate, and zirconium ethylacetoacetate. The adhesive strength can be further increased by using other adhesion promoters in combination.

[0079] The additional adhesion promoter may be contained in the curable polyorganosiloxane composition in an amount of, for example, 10 parts by mass or less, specifically, 0.01 to 10 parts by mass, and more specifically, 0.1 to 5 parts by mass, per 100 parts by mass of component (A). One type of adhesion promoter may be used alone, or two or more types may be used in combination.

[0080] <Solvent> The curable polyorganosiloxane composition may contain a solvent. In this case, the curable polyorganosiloxane composition may be dissolved in a suitable solvent at a desired concentration depending on its application and purpose. The concentration of the solvent may be, for example, 80 parts by mass or less, 50 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less, relative to 100 parts by mass of the composition. From the viewpoint of adjusting the viscosity of the curable composition, it is preferable to contain a solvent. By containing a solvent, the handleability of the curable composition may be improved.

[0081] One aspect of the present invention is an adhesive comprising the curable polyorganosiloxane composition. In an article using the curable polyorganosiloxane composition of the present invention as an adhesive, the cured product of the composition and various substrates may have an adhesive portion, and the shape of the adhesive portion is not limited. For example, one aspect of a method for producing an article comprising an adhesive portion between a substrate and a cured product of a composition includes a step of preparing a component and a composition comprising a substrate; a step of applying the composition to the surface of the substrate; and a step of curing the composition to adhere the substrate and the cured product of the composition.

[0082] The substrate to which the adhesive containing the curable polyorganosiloxane composition of the present invention is applied is not particularly limited in terms of its material. As the substrate, metals such as aluminum, copper, nickel, iron, steel, brass, and stainless steel; engineering plastics such as epoxy resin, polyester resin such as polyethylene terephthalate and polybutylene terephthalate (PBT) resin, polycarbonate resin, acrylic resin, polyimide resin, phenolic resin, polyamide resin, polyphenylene sulfide (PPS) resin, and modified polyphenylene ether (PPE) resin; and glass can be used. In addition, if necessary, the wall surface of the gap may be subjected to a primer treatment according to a conventional method. The shape and thickness of the substrate are not particularly limited.

[0083] The adhesive containing the curable polyorganosiloxane composition is applied to the surface of the part including the substrate at a predetermined thickness by a method such as dripping, pouring, casting, extrusion from a container, coating such as bar coating and roll coating, screen printing, dipping, brushing, spraying, and dispensing. These methods are known to those skilled in the art. The composition may be applied entirely and uniformly on the surface of the part, or may be applied unevenly or partially, such as in lines, stripes, dots, etc. The application thickness of the composition is usually 0.01 to 3 mm, preferably 0.05 to 2 mm.

[0084] The composition can be attached to the object to be bonded by injection, dripping, casting, pouring, extrusion from a container, or by integral molding such as transfer molding or injection molding, and then left at room temperature (e.g., 23°C) to harden, thereby simultaneously adhering to the object to be bonded. The hardening time is preferably one week or less, more preferably 72 hours or less, and particularly preferably 24 hours or less from the viewpoint of productivity.

[0085] The article using the curable polyorganosiloxane composition of the present invention as an adhesive has excellent durability, including water resistance and oil resistance of the adhesive surface, so that it can meet the demand for bonding metals such as aluminum and aluminum die casting, and engineering plastics such as PBT and PET with silicone.The article can be used effectively as various parts in aircraft, automobile applications, and electronic materials fields. EXAMPLES

[0086] The composition of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the embodiments of these examples.

[0087] (1) Preparation of Moisture-Curable Silicone Composition The components in the composition shown in Table 1 were kneaded and mixed as follows. (A) 800g of polydimethylsiloxane capped with trimethoxysilyl groups at the end with a viscosity of 20,000 mPas and 120g of fumed silica surface-treated with 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane were kneaded at room temperature for 20 minutes, then kneaded under reduced pressure for 1 hour, then 200g of polydimethylsiloxane capped with trimethoxysilyl groups at the end with a viscosity of 20,000 mPas was added, kneaded at room temperature for 20 minutes, further added polydimethylsiloxane capped with trimethylsilyl groups at the end with a viscosity of 20, kneaded at room temperature for 20 minutes, and then kneaded under reduced pressure for 1 hour. Next, the components shown in Table 1 were mixed in the ratios shown and kneaded under reduced pressure for 20 minutes to defoam the mixture, thereby preparing a moisture-curable silicone composition. Here, compound 1 is a compound having the following structure. [ka] Compound 1 was synthesized as follows. 74.5 g of triallyl isocyanurate, 98 g of 3-mercaptopropyltrimethoxysilane, and 200 g of toluene were added in this order to a 500 mL separable flask, and the mixture was stirred at room temperature for 10 minutes. 0.5 g of AIBN (azobisisobutyronitrile) was added, and the mixture was stirred at room temperature for 10 minutes under a nitrogen atmosphere. The mixture was heated to 50° C. while continuing to stir, and the reaction was continued for 6 hours. Next, while continuing stirring, the toluene and unreacted precursor, 3-mercaptopropyltrimethoxysilane contained in the compound were removed at 120° C. and a vacuum of 10 mmHg or less for 3 hours. The mixture was cooled to room temperature to obtain compound 1.

[0088] <Preparation of Moisture-Curable Silicone Composition> As Examples 2 and 3, moisture-curable silicone compositions were prepared according to the procedure of Example 1, except that the amount of compound 1 was adjusted as shown in Table 1. As Examples 4 to 10, the compound corresponding to (D) was changed to the following compounds 2 to 8, and the amount added was adjusted as shown in Table 1. As a result, moisture-curable silicone compositions were prepared according to the procedure of Example 1, except that the compound corresponding to (D) was not added (Comparative Example 1), 0.5 parts by mass of 1,3,5-tris(trimethoxysilylpropyl)isocyanurate was added instead of the compound corresponding to (D) (Comparative Example 2), and the amount of compound 1 was 20.41 parts by mass (Comparative Example 3). As a result, moisture-curable silicone compositions of the comparative examples were prepared according to the procedure of Example 1, except that the compound corresponding to (D) was not added (Comparative Example 1), 0.5 parts by mass of 1,3,5-tris(trimethoxysilylpropyl)isocyanurate was added instead of the compound corresponding to (D) (Comparative Example 2), and the amount of compound 1 was 20.41 parts by mass (Comparative Example 3). Compound 2 is a compound having the following structure. Compound 2 was obtained by adjusting the amount of raw materials in the same manner as compound 1. Compound 3 was obtained by changing the number of epoxy groups from compound 1 in a similar manner. Compounds 4 to 8 were obtained in the same manner by changing the substance that becomes the main skeleton from compound 1. The structures of each compound are as follows: [ka]

[0089] [Table 1]

[0090] (Evaluation method) <Hardness (Type-A hardness), tensile strength and elongation> The polyorganosiloxane composition was dispensed and molded into a 2 mm sheet, and then left to cure for 7 days in an atmosphere of 23°C and 50% RH to obtain a cured product of the polyorganosiloxane composition. The hardness (initial hardness) of the obtained cured product was measured using a type A hardness tester. In addition, the tensile strength was measured according to JIS K 6249. Furthermore, the elongation was measured according to JIS K 6249.

[0091] <Tuck free time> The polyorganosiloxane composition was applied to the surface of a 5 cm diameter aluminum petri dish whose surface had been cleaned with an organic solvent, and the time it took to touch the surface with a finger and confirm that it was dry was measured in an environment of 23°C and 50% relative humidity (RH).

[0092] <Shear adhesive strength> The following method was used to evaluate the shear adhesive strength. The silicone composition was applied to one end of the test piece and spread evenly, and then the other end of the test piece was attached to the other end so that the adhesive surface was 25 mm in the width direction and 10 mm in the length direction to obtain a test piece. The test piece was placed in an oven adjusted to the temperature of the curing conditions while fixed with a jig, and cured for the time period of the curing conditions. After the temperature of the test piece returned to room temperature (23°C), the prepared test piece was measured with a tensile tester at a tensile speed of 10 mm / min, and the "tensile shear adhesive strength" (MPa) was obtained. The details of the test were in accordance with JIS K 6249.

[0093] <Cohesive failure rate> The cohesive failure rate is the percentage of silicone layers that break without peeling at the interface of the opposing adherends in a shear bond strength test. A cohesive failure rate of 100% indicates that the adhesive strength (adhesion) is adequately maintained. After measuring the shear bond strength as described in "shear bond strength" above, the area of ​​the silicone layer bonded to each adherend was divided by the coating area to determine the cohesive failure rate (area%). For details of the test, please refer to JIS K 6249.

[0094] <Test 1: Water resistance test> Regarding the shear bond strength and cohesive failure rate related to adhesive force, the compositions of the examples and comparative examples were applied to glass, aluminum, copper, and PPS, and the shear bond strength and cohesive failure rate were measured immediately after application (0:00). The samples were then immersed in 70°C water or a 50°C sodium chloride aqueous solution (salt water), and similar measurements were performed after 7 days and after 14 days in the case of 70°C water. These evaluation results are summarized in Tables 2 to 6.

[0095] [Table 2]

[0096] [Table 3]

[0097] [Table 4]

[0098] [Table 5]

[0099] [Table 6]

[0100] <Test 2: Oil resistance test> Using the same method as in Test 1, the compositions of the Examples and Comparative Examples were applied to aluminum and mild steel, and immersed in automobile transmission oil (Toyota Autofluid Type T-IV) in an environment of 120°C. The shear bond strength and cohesive failure rate, which are related to adhesive strength, were measured for the aluminum after 100 hours and 240 hours, and for the mild steel after 100 hours and 14 days. The evaluation results are summarized in Tables 7 and 8.

[0101] [Table 7]

[0102] [Table 8]

[0103] From Tables 2 to 6, in the comparative example not having the component (D) specified in the present invention, the adhesive strength and cohesive failure rate for each substrate are significantly reduced by contact with moisture (salt water), whereas the composition of the present invention has high adhesion to all substrates and high water resistance. In addition, by appropriately adjusting the amount of the component (D), it was shown that the composition has high adhesion to all substrates and high water resistance. This tendency is also the same when it comes into contact with oil. Since silicone is compatible with oil, there is concern about swelling due to oil and deterioration of physical properties and adhesiveness due to additives contained in the oil. However, the composition of the present invention was able to maintain high adhesion even in the presence of oil. Overall, it was shown that the composition of the present invention is also excellent as an adhesive for the internal structure of an automobile, which is likely to come into contact with hot oil. [Industrial Applicability]

[0104] The composition of the present invention is a moisture-curable silicone composition that has high adhesion and excellent water resistance, salt water resistance, and oil resistance, and the present invention provides a moisture-curable silicone composition that has excellent adhesion to various substrates that come into frequent contact with moisture or oil.

Claims

1. (A) a polyorganosiloxane having two or more hydroxyl groups or hydrolyzable groups bonded to silicon atoms in each molecule; (B) -OR bonded to a silicon atom ２ A group, where R ２ each occurrence of each independently represents a hydrogen atom or a monovalent organic group; (C) condensation catalyst; (D) silicon-based adhesion promoters (excluding those falling under (A) or (B) above) which are compounds having in one molecule one or more adhesion-imparting functional groups selected from the group consisting of aromatic hydrocarbon-containing groups, epoxy group-containing groups, and linear, branched, or cyclic aliphatic unsaturated hydrocarbon groups, and which have in one molecule at least one heteroatom other than the adhesion-imparting functional groups; and (E) Inorganic filler and the content of the component (D) per 100 parts by mass of the component (A) is 0.05 to 20 parts by mass.

2. 2. The moisture-curable silicone composition according to claim 1, wherein the component (D) is at least one compound selected from the group consisting of sulfur compounds, nitrogen compounds, and phosphorus compounds.

3. The component (D) is SiR ５ ３－ｎ (OR ５ ) ｎ A group, where R ５ is a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and n is 1, 2, or 3), and / or a partial hydrolysis condensate thereof.

4. 4. The moisture-curable silicone composition according to claim 3, wherein component (D) further has one or more groups selected from the group consisting of an aromatic hydrocarbon-containing group, an epoxy group-containing group, and an aliphatic unsaturated hydrocarbon group.

5. The component (A) has R at both ends. ａ ３－ｍ R ３ ｍ SiO １／２ It is blocked by units, and the intermediate unit is R ３ ２ SiO ２／２ The linear polyorganosiloxane unit (where R ａ is a hydroxyl group or a hydrolyzable group, R ３ is a hydrogen atom or a monovalent hydrocarbon group that has no aliphatic unsaturated bonds, and m is 0, 1, or 2.

6. The component (B) is represented by the following formula: R １ ｎ Si(OR ２ ) ４-ｎ (In the formula, R １ is independently in each occurrence a substituted or unsubstituted monovalent hydrocarbon radical having 1 to 12 carbon atoms; R ２ each occurrence independently represents a hydrogen atom or an alkyl or alkenyl group having 1 to 12 carbon atoms, which optionally has a -C(=O)-, -NR'- or -N=C(R')- group at its terminal and in which one or more hydrogen atoms are optionally substituted by a halogen or an alkoxy group (wherein R' is an alkyl group having 1 to 6 carbon atoms, which may form a ring together with the carbon portion of the alkyl or alkenyl group); n is 0, 1 or 2. The curable composition according to any one of claims 1 to 4, comprising a compound represented by the following formula (I): or a partial hydrolysis condensate thereof.

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