JP6580370B2 - Room temperature curable polyorganosiloxane composition and electrical / electronic equipment - Google Patents

Description

  The present invention relates to a room temperature curable polyorganosiloxane composition and an electric / electronic device, and in particular, forms a cured film excellent in scratch resistance and adhesion durability, and is useful as a coating material for electric / electronic devices. The present invention relates to a curable polyorganosiloxane composition and an electric / electronic device having a cured coating of the room temperature curable polyorganosiloxane composition.

  Conventionally, various room temperature-curable polyorganosiloxane compositions that are cured at room temperature to produce a rubber-like cured product are known. Among them, for applications such as coating materials and potting materials for electrical and electronic parts, it is a type that causes a curing reaction by contact with moisture in the air, and releases alcohol, acetone, etc. during curing Is commonly used. Such types of room temperature curable polyorganosiloxane compositions have good workability, and the alcohol and acetone released during curing are less corrosive to metals, which may corrode electrodes and wiring. There are few advantages and it has the advantage that it is excellent also in adhesiveness.

  In particular, as a conformal coating agent applied to protect the surface of an electric / electronic component or a circuit board on which the electric / electronic component is mounted from a use environment, a coating material made of a low-viscosity room temperature-curable polyorganosiloxane composition (for example, , And Patent Documents 1 and 2) and a coating material in which a silicone resin is dissolved in a solvent is used.

However, a coating material made of a low-viscosity room temperature-curable polyorganosiloxane composition has a cured film that is brittle and has low hardness, and scratch strength such as scratch resistance is not sufficient.
In addition, solvent-type coating materials containing silicone resins require a solvent removal process by heating during curing, so the volatilization of the solvent can lead to deterioration of the work environment and the electrical / electronic components and circuit boards on which they are mounted. There was a risk of causing corrosion and deterioration. Furthermore, in order to improve the working environment, a high investment was required to recover the solvent without releasing it into the atmosphere.

JP-A-7-173435 JP 7-238259 A

  The present invention has been made to solve these problems, and is a room temperature curable polyorgano that forms a cured film having a low viscosity, no solvent, good coatability, high hardness, and excellent scratch resistance. An object is to provide a siloxane composition.

The room temperature curable polyorganosiloxane composition of the present invention comprises:
A polyorganosiloxane obtained by an alkoxylation reaction of a silanol group-containing polyorganosiloxane (A1a) containing a bifunctional siloxane unit and a trifunctional siloxane unit, having a silanol group at the terminal and a three-dimensional network structure A bifunctional siloxane unit and a trifunctional siloxane unit are contained so that the molar ratio of the bifunctional siloxane unit to the trifunctional siloxane unit is 0.5 to 2.0 and bonded to a silicon atom. The first polyorganosiloxane (A1) having two alkoxy groups bonded to the terminal silicon atom and having a weight average molecular weight (Mw) of 2,000 to 100,000 is 20 to 95 masses. And
80-5 parts by mass of a second polyorganosiloxane (A2) having two or more alkoxy groups bonded to silicon atoms in the molecule and having a linear shape and a viscosity at 23 ° C. of 3 mPa · s to 500 mPa · s For 100 parts by mass of the mixed polyorganosiloxane mixture (A),
(B) It contains 0.1 to 15 parts by mass of an organic titanium compound as a curing catalyst.

  The electrical / electronic device of the present invention is characterized in that it has a film made of a cured product of the room temperature-curable polyorganosiloxane composition of the present invention on the surface of the electrode and / or wiring.

  In the present invention, the “silanol group” refers to a group in which a hydroxyl group is bonded to a silicon atom. Further, “normal temperature” means a normal temperature that is neither heated nor cooled, for example, 23 ° C.

  The room temperature curable polyorganosiloxane composition of the present invention has a low viscosity and good coating properties, and can be applied as it is by a normal coating method without being diluted with a solvent. And a coating film hardens | cures rapidly at room temperature, forms a hardened film with high hardness, excellent scratch resistance, and good adhesion durability. Therefore, it is useful for applications such as coating materials and potting materials for electric / electronic devices, and is particularly suitable for applications for coating electric / electronic components such as conformal coating agents.

It is sectional drawing which shows an example of the electric / electronic device of this invention.

Embodiments of the present invention will be described below.
A room temperature-curable polyorganosiloxane composition according to an embodiment of the present invention includes a bifunctional siloxane unit and a trifunctional siloxane obtained by an alkoxylation reaction of a silanol group-containing polyorganosiloxane (A1a) having a three-dimensional network structure. The first polyorganosiloxane (A1) containing units at a predetermined molar ratio and two or more alkoxy groups bonded to silicon atoms (hereinafter simply referred to as alkoxy groups) in the molecule, and are liquid at room temperature and predetermined 100 parts by mass of the polyorganosiloxane mixture (A) obtained by mixing the second polyorganosiloxane (A2) having a viscosity of 0.1 to 15 parts by mass of (B) organometallic compound as a curing catalyst. contains.
The room temperature curable polyorganosiloxane composition of the embodiment can further contain a silane compound represented by the formula (c1) described later as the component (C).
Hereinafter, each component which comprises the room temperature curable polyorganosiloxane composition of embodiment, a content rate, etc. are demonstrated.

[(A) Polyorganosiloxane mixture]
In the embodiment of the present invention, the polyorganosiloxane mixture as the component (A) is a polymer component serving as a base of the present composition, the first polyorganosiloxane (A1) having a three-dimensional network structure, and an alkoxy group. Is mixed with a second polyorganosiloxane (A2) having a predetermined viscosity and liquid at room temperature.

Component (A1) The first polyorganosiloxane component (A1) is a three-dimensional network having an alkoxy group at the terminal, obtained by alkoxylation of a silanol group-containing polyorganosiloxane (A1a) having a three-dimensional network structure. It is a polyorganosiloxane having a structure. The (A1) first polyorganosiloxane is represented by a bifunctional siloxane unit (hereinafter referred to as D1 unit) represented by the formula: R ⁰ ₂ SiO _2/2 and a formula: R ⁰ SiO _3/2 . The trifunctional siloxane unit (hereinafter referred to as T1 unit) has a molar ratio of D1 unit to T1 unit (number of moles of D1 unit / number of moles of T1 unit; hereinafter also referred to as D1 / T1). It contains so that it may become the range of 5-2.0.

In the formulas representing the D1 unit and the T1 unit, R ⁰ is independently a monovalent hydrocarbon group in which an unsubstituted monovalent hydrocarbon group or a part of the hydrogen atom is substituted with a halogen atom or a cyanoalkyl group. It is a hydrocarbon group. Specific examples of the unsubstituted monovalent hydrocarbon group include methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, octyl groups, decyl groups, dodecyl groups, and other alkyl groups; cyclohexyl groups, etc. Cycloalkyl groups; alkenyl groups such as vinyl groups and allyl groups; aryl groups such as phenyl groups, tolyl groups, and xylyl groups; aralkyl groups such as benzyl groups, 2-phenylethyl groups, and 2-phenylpropyl groups. . The substituted monovalent hydrocarbon group includes, for example, a chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoro in which a part of hydrogen atoms of the monovalent hydrocarbon group is substituted with a halogen atom. Examples thereof include a halogenated alkyl group such as a propyl group and a 3-cyanopropyl group in which a part of the hydrogen atoms of the monovalent hydrocarbon group is substituted with a cyanoalkyl group.

The silanol group-containing polyorganosiloxane (A1a) having a three-dimensional network structure has the D1 unit and the T1 unit, and optionally has the formula: R ⁰ ₃ SiO _1/2 (R ⁰ is the same as described above. ) Is a polyorganosiloxane having a monofunctional siloxane unit (hereinafter referred to as M1 unit). The hydroxyl group constituting the silanol group is preferably bonded to the silicon atom constituting the D1 unit and the T1 unit.

  This silanol group-containing polyorganosiloxane (A1a) is prepared by, for example, using one or more silane compounds as a D1 unit source and one or more silane compounds as a T1 unit source in a known method. It can be obtained by hydrolyzing and condensing. The “D1 unit source” means that D1 units in the silanol group-containing polyorganosiloxane (A1a) are formed by hydrolysis and condensation. Similarly, “T1 unit source” means that T1 units in the silanol group-containing polyorganosiloxane (A1a) are formed by hydrolysis and condensation.

  Here, as a silane compound which is a D1 unit source, dimethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldisilane. Examples include dialkoxysilanes such as ethoxysilane, and dichlorosilanes such as dimethyldichlorosilane, phenylmethyldichlorosilane, phenylethyldichlorosilane, diphenyldichlorosilane, vinylmethyldichlorosilane, and vinylethyldichlorosilane. From the viewpoint of economy and ease of use, dimethyldimethoxysilane is preferably used.

  Examples of the silane compound as the T1 unit source include trialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane, Mention may be made of trichlorosilanes such as methyltrichlorosilane, vinyltrichlorosilane and phenyltrichlorosilane. From the viewpoint of the reactivity of hydrolysis and condensation reaction, use of methyltrimethoxysilane, vinyltrimethoxysilane, methyltrichlorosilane, vinyltrichlorosilane, and phenyltrichlorosilane is preferable. Moreover, methyltrimethoxysilane and methyltrichlorosilane are preferable from the viewpoint of economy and flexibility of the cured film.

  The weight average molecular weight (Mw) of the silanol group-containing polyorganosiloxane as the component (A1a) is preferably from 2,000 to 100,000, more preferably from 3,000 to 70,000. Mw is a value obtained by GPC (gel permeation chromatograph) based on polystyrene.

  (A1a) Preparation of (A1) first polyorganosiloxane by alkoxylation of silanol group-containing polyorganosiloxane can be carried out, for example, by the following method.

<First method>
The silanol group-containing polyorganosiloxane (A1a) having a silanol group at the terminal is mixed with the silanol group-containing polyorganosiloxane (A1a) having the three-dimensional network structure, and this silanol group-containing polyorganosiloxane mixture is mixed. In contrast, (A1c) a silane compound having two or more alkoxy groups is added and reacted.

Here, as the linear silanol group-containing polyorganosiloxane (A1b), α, ω-dihydroxypolydialkylsiloxane having silanol groups at both ends is preferably used. The Mw of the (A1b) silanol group-containing polyorganosiloxane is preferably in the range of 200 to 200,000, more preferably in the range of 300 to 100,000.
The (A1c) silane compound added to the silanol group-containing polyorganosiloxane mixture is not particularly limited as long as it is a silane having two or more alkoxy groups. Tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, dimethyl Examples include alkoxysilanes such as dimethoxysilane and dimethyldiethoxysilane. Among these, methyltrimethoxysilane, vinyltrimethoxysilane, and tetramethoxysilane are preferable from the viewpoint of reactivity, ease of handling, and high reactivity after alkoxylation. From the viewpoint of safety and economy, methyltrimethoxysilane is preferred. Silane is particularly preferred.

(A1c) Addition of a silane compound having two or more alkoxy groups to a mixture of a three-dimensional network structure silanol group-containing polyorganosiloxane (A1a) and a linear silanol group-containing polyorganosiloxane (A1b) and reacting Then, a dealcoholization reaction occurs between the silanol group of the polyorganosiloxane (A1a) and the silanol group of the polyorganosiloxane (A1b) and the alkoxy group of the (A1c) silane compound, and the terminal is blocked with an alkoxysilyl group. Polyorganosiloxane is obtained. At this time, a part of the silanol group of the polyorganosiloxane (A1a) and a part of the silanol group of the polyorganosiloxane (A1b) are dehydrated and condensed to form a siloxane bond, resulting in an increase in molecular weight. .
Thus, a terminal alkoxy group-containing polyorganosiloxane having a three-dimensional network structure as component (A1) is obtained.

<Second method>
A linear alkoxy group-containing polyorganosiloxane (A1d) having an alkoxy group at the terminal is added to the silanol group-containing polyorganosiloxane (A1a) having the above three-dimensional network structure and reacted.

  Here, as the linear alkoxy group-containing polyorganosiloxane (A1d), it is preferable to use α, ω-alkoxypolydialkylsiloxane having an alkoxy group at both ends, and two alkoxy groups at each end. More preferred is the use of α, ω-dialkoxypolydialkylsiloxanes having Moreover, Mw of this (A1d) alkoxy group containing polyorganosiloxane has the preferable range of 2,000-150,000.

When a linear alkoxy group-containing polyorganosiloxane (A1d) is added to and reacted with a silanol group-containing polyorganosiloxane (A1a) having a three-dimensional network structure, the silanol group of the polyorganosiloxane (A1a) and an alkoxy group are contained. A dealcoholization reaction with the alkoxy group of the polyorganosiloxane (A1d) occurs. And polyorganosiloxane (A1a) and an alkoxy-group containing polyorganosiloxane (A1d) are couple | bonded through the siloxane bond produced | generated by dealcoholization reaction.
Thus, a terminal alkoxy group-containing polyorganosiloxane having a three-dimensional network structure as component (A1) is obtained.

The terminal alkoxy group-containing polyorganosiloxane (A1) having a three-dimensional network structure thus obtained is a polyorgano in which the molar ratio (D1 / T1) of D1 units to T1 units is in the range of 0.5 to 2.0. Siloxane.
When D1 / T1 is less than 0.5, a polyorganosiloxane composition having a viscosity suitable for thin film coating cannot be obtained. Moreover, also when a cured film is obtained, adhesive durability becomes inadequate. On the other hand, when D1 / T1 exceeds 2.0, a cured film excellent in scratch resistance cannot be obtained.
D1 / T1 is preferably in the range of 0.5 to 1.9.

  (A1) The terminal alkoxy group-containing polyorganosiloxane having a three-dimensional network structure may contain M1 units in addition to D1 units and T1 units. When M1 units are contained, the ratio of M units to the number of moles of all units is preferably 20 mol% or less.

The first polyorganosiloxane which is the component (A1) can be represented by an average composition formula: R ¹ _a Si (OR ² ) _b O _{{4- (a + b)} / 2} (a1).
In the present specification, the polyorganosiloxane represented by the formula (a1) is also referred to as polyorganosiloxane (a1). Hereinafter, abbreviations including symbols representing the formulas may be used for compounds represented by other formulas.

In formula (a1), R ¹ is an unsubstituted monovalent hydrocarbon group, or a monovalent hydrocarbon group in which a part of the hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group, and a plurality of R ¹ are They may be the same or different. R ² is an alkyl group or an alkoxy-substituted alkyl group in which a part of hydrogen atoms of the alkyl group is substituted with an alkoxy group. A plurality of R ² may being the same or different.

Specific examples of the unsubstituted monovalent hydrocarbon group for R ¹ include methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, octyl groups, decyl groups, dodecyl groups, and other alkyl groups; cyclohexyl A cycloalkyl group such as a vinyl group; an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group, a tolyl group or a xylyl group; an aralkyl group such as a benzyl group, a 2-phenylethyl group or a 2-phenylpropyl group; Is mentioned. The substituted monovalent hydrocarbon group includes, for example, a chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoro in which a part of hydrogen atoms of the monovalent hydrocarbon group is substituted with a halogen atom. Examples thereof include a halogenated alkyl group such as a propyl group and a 3-cyanopropyl group in which a part of the hydrogen atoms of the monovalent hydrocarbon group is substituted with a cyanoalkyl group. R ¹ is preferably a methyl group because it is easy to synthesize, has a low viscosity relative to the molecular weight, and gives good physical properties to the cured product (cured coating). However, when it is necessary to impart heat resistance or cold resistance to the cured coating, it is preferable that a part of R ¹ is an aryl group such as a phenyl group.

Specific examples of the alkyl group for R ² include a methyl group, an ethyl group, a propyl group, and a butyl group. Specific examples of the alkoxy-substituted alkyl group include a 2-methoxyethyl group and a 2-ethoxyethyl group. And 3-methoxypropyl group. R ² is preferably a methyl group.

  In the formula (a1), a and b are positive numbers satisfying 0.5 ≦ a ≦ 1.7 and 0 <b <0.5. a and b are preferably positive numbers satisfying 0.8 ≦ a ≦ 1.5 and 0 <b <0.4. It is more preferable that a and b are positive numbers satisfying 0.9 ≦ a ≦ 1.4 and 0 <b <0.3.

  The Mw of the component (A1) is preferably 2,000 to 50,000, and more preferably 3,000 to 30,000. (A1) A component consists of 1 type, or 2 or more types of polyorganosiloxane (a1). When (A1) component consists of 1 type of polyorganosiloxane (a1), Mw of this polyorganosiloxane (a1) is 2,000-100,000. When the component (A1) is composed of two or more polyorganosiloxanes (a1), if the Mw as the component (A1) is 2,000 to 100,000, the Mw of each polyorganosiloxane (a1) is not necessarily 2 , But need not be in the range.

Component (A2) The second polyorganosiloxane that is component (A2) has two or more alkoxy groups in the molecule, and the molecular structure is not particularly limited as long as the viscosity is 3 mPa · s to 500 mPa · s. For example, it may be a straight chain or a structure having a branched chain (hereinafter referred to as a branched chain). A linear polyorganosiloxane is preferred because the viscosity is easily set in the above range. In addition, when using branched polyorganosiloxane, in order to maintain the said viscosity as the whole (A2) component, it is preferable to use together with a linear polyorganosiloxane.

  When the viscosity of the component (A2) is less than 3 mPa · s, the resulting cured product has poor rubber elasticity, and when it exceeds 500 mPa · s, the compatibility with the component (A1) is deteriorated and the composition is uniform. Cannot be obtained. The viscosity of the component (A2) is preferably in the range of 5 mPa · s to 300 mPa · s, more preferably in the range of 5 mPa · s to 100 mPa · s.

  The component (A2) is composed of one or more polyorganosiloxanes. When the component (A2) is composed of one kind of polyorganosiloxane, the polyorganosiloxane has two or more alkoxy groups in the molecule and has a viscosity of 3 mPa · s to 500 mPa · s. When the component (A2) is composed of a mixture of two or more polyorganosiloxanes, each of the polyorganosiloxanes constituting the component (A2) has two or more alkoxy groups in the molecule, and the mixture is What is necessary is just to satisfy the above-mentioned definition of viscosity. Therefore, in this case, the viscosity of the individual polyorganosiloxanes constituting the component (A2) does not necessarily satisfy the above definition, but the viscosity of each polyorganosiloxane preferably satisfies the above definition.

  When the component (A2) is a linear polyorganosiloxane, each of the two or more alkoxy groups bonded to the silicon atom may be bonded to a silicon atom at the molecular end, or an intermediate silicon atom. May be bonded to. It is preferable that at least one alkoxy group is bonded to the silicon atom at the molecular end. In this case, all of the alkoxy groups of the linear polyorganosiloxane may be bonded to the silicon atom at the molecular end, or at least one alkoxy group may be bonded to the middle silicon atom. Good.

The linear polyorganosiloxane constituting the component (A2) is preferably a polyorganosiloxane having both ends alkoxysilyl group blocked represented by the following general formula (a21).

In formula (a21), R ³ is an alkyl group or an alkoxy-substituted alkyl group in which part of the hydrogen atoms of the alkyl group is substituted with an alkoxy group, and represents an average composition of the aforementioned component (A1) (a1 Group similar to R ² in the formula ( ¹ ). R ³ is preferably a methyl group.

R ⁴ is an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which a part of hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group. The plurality of R ⁴ may be the same as or different from each other. R ^{5 is} also an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which a part of hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group. Several R < ⁵ > may mutually be same or different.
Examples of R ⁴ and R ⁵ include the same groups as R ¹ in formula (a1) showing the average composition of the component (A1).

R ⁴ and R ⁵ are preferably methyl groups because they are easy to synthesize, have a low viscosity relative to the molecular weight, and give good physical properties to the cured product (cured coating). However, when it is necessary to impart heat resistance and cold resistance to the cured coating, it is preferable that a part of R ⁴ and / or R ⁵ is an aryl group such as a phenyl group.

  In formula (a21), X represents a divalent oxygen (oxy group) or a divalent hydrocarbon group. Two Xs may be the same or different. Examples of the divalent hydrocarbon group include alkylene groups such as methylene group, ethylene group, propylene group and trimethylene group, and arylene groups such as phenylene group. In view of ease of synthesis, a divalent oxygen atom (oxy group) or an ethylene group is preferable, and an oxy group is particularly preferable.

  In the formula (a21), d is 0 or 1. n is an integer with which the viscosity of the polyorganosiloxane (a21) is 3 mPa · s to 500 mPa · s, specifically, an integer of 1 ≦ n <250. The viscosity of the polyorganosiloxane (a21) is preferably in the range of 5 mPa · s to 100 mPa · s, and the value of n is preferably an integer of 3 to 100.

  Such polyorganosiloxane (a21) is obtained, for example, by ring-opening polymerization or ring-opening copolymerization of a cyclic diorganosiloxane low monomer such as octamethylsiloxane with an acidic catalyst or an alkaline catalyst in the presence of water. The obtained both-end hydroxyl group-containing diliganopolysiloxane can be obtained by encaping with methyltrimethoxysilane or the like.

  The polyorganosiloxane (a21) is preferably a methyldimethoxysilyl group or a trimethyl group at both ends represented by the following formula (where d is 0 or 1, and n is the same as in the formula (a21) including preferred embodiments). Examples thereof include polydimethylsiloxane having a methoxysilyl group.

In addition, as the component (A2), the above-described trifunctional siloxane unit (T1 unit) (wherein one organic group bonded to silicon is an unsubstituted monovalent hydrocarbon group, or a part of hydrogen atoms are halogenated) A monovalent hydrocarbon group substituted with an atom or a cyanoalkyl group) and / or a polyorgano having a three-dimensional network structure having a tetrafunctional siloxane unit (Q unit) represented by the formula: SiO _4/2 Siloxane can be used together with the linear polyorganosiloxane. The polyorganosiloxane having a three-dimensional network structure is composed of the aforementioned monofunctional siloxane unit (M1 unit) (however, the three organic groups bonded to silicon are independently an unsubstituted monovalent hydrocarbon group. Or a monovalent hydrocarbon group in which a part of hydrogen atoms are substituted with a halogen atom or a cyanoalkyl group) and / or a bifunctional siloxane unit (D1 unit) (however, two organic bonded to silicon) The group can independently have an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which some of the hydrogen atoms are substituted with halogen atoms or cyanoalkyl groups.

  Similarly to the linear polyorganosiloxane, the viscosity of the polyorganosiloxane having such a three-dimensional network structure is 3 mPa · s to 500 mPa · s when used alone, and is 5 mPa · s to 100 mPa · s. It is preferable to be in the range. The viscosity may be in the above range when the polyorganosiloxane having a three-dimensional network structure is combined with the linear polyorganosiloxane as the component (A2).

The polyorganosiloxane having a three-dimensional network structure used as the component (A2) has two or more alkoxy groups bonded to silicon atoms in the molecule. The alkoxy group may be bonded to any unit silicon atom. Examples of the alkoxy group possessed by the polyorganosiloxane having a three-dimensional network structure include groups similar to OR ^{3 in the} formula representing the polyorganosiloxane (a21). As this alkoxy group, a methoxy group and an ethoxy group are preferable. An organic group other than an alkoxy group bonded to a silicon atom, that is, an unsubstituted monovalent hydrocarbon group, or a part of the hydrogen atom of the polyorganosiloxane having a three-dimensional network structure is substituted with a halogen atom or a cyanoalkyl group Examples of the monovalent hydrocarbon group include the same groups as R ^{4 in the} formula showing the polyorganosiloxane (a21). The organic group is preferably a methyl group.

Further, as the component (A2), a polyorganosiloxane that is a partial hydrolysis condensate of a silane compound represented by the formula: R ⁶ _e Si (OR ⁷ ) _4-e (a22) It can be used together with organosiloxane, for example, polyorganosiloxane (a21). Further, as the component (A2), a mixture of the linear polyorganosiloxane, for example, the polyorganosiloxane (a21) and the polyorganosiloxane having the three-dimensional network structure is further added to the silane compound (a22). A partial hydrolysis condensate can also be blended. Each of the linear polyorganosiloxane (for example, polyorganosiloxane (a21)), the three-dimensional network structure polyorganosiloxane, and the partial hydrolysis-condensation product of the silane compound (a22) is used alone. You may use, and may mix and use 2 or more types.

In the formula (a22), R ⁶ is an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which a part of the hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group, Examples thereof are the same groups as R ⁴ in formula (a21) representing organosiloxane (a21). R ⁶ is preferably a methyl group or a vinyl group, and particularly preferably a methyl group. R ⁷ is an alkyl group or an alkoxy-substituted alkyl group, and examples thereof include the same groups as R ³ in the formula (a21) showing the linear polyorganosiloxane (a21). R ⁷ is preferably a methyl group or an ethyl group. In the formula (a22), e is 0, 1 or 2.

  Examples of the silane compound (a22) include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetra Examples include propoxysilane, tetraisopropoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, vinylmethyldimethoxysilane, and dimethyldiethoxysilane. And the partial hydrolysis-condensation product of a silane compound (a22) is obtained by, for example, partially hydrolyzing a silane compound such as methyltrimethoxysilane by the presence of water, an acidic catalyst or an alkaline catalyst. In addition, silanol groups generated by partial hydrolysis may be encapped with methyltrimethoxysilane or the like.

  The viscosity of the polyorganosiloxane that is a partial hydrolysis-condensation product of the silane compound (a22) is also combined with the linear polyorganosiloxane, for example, the polyorganosiloxane (a21) or the polyorganosiloxane having the three-dimensional network structure. (A2) The viscosity at the time of setting it as a component should just be a viscosity used as 3mPa * s-500mPa * s. The viscosity of the polyorganosiloxane that is a partial hydrolysis-condensation product of the silane compound (a22) is preferably in the range of 5 mPa · s to 100 mPa · s.

  The number of Si in the partially hydrolyzed condensate of the silane compound (a22) is selected so that the viscosity in the partially hydrolyzed condensate is in the above range.

  As the component (A2), for example, in the case where a partial hydrolysis condensate of the polyorganosiloxane (a21) and the silane compound (a22) is used in combination, the blending ratio is 100 parts by mass of the polyorganosiloxane (a21). In such a case, the proportion of the partially hydrolyzed condensate of the silane compound (a22) is preferably 1 to 200 parts by mass, and more preferably 10 to 100 parts by mass.

  The component (A) which is the base component of the room temperature curable polyorganosiloxane composition of the present invention is such (A2) second polyorganosiloxane, that is, has two or more alkoxy groups in the molecule, and Liquid polyorganosiloxane having a viscosity of 3 mPa · s to 500 mPa · s and the above-described (A1) first polyorganosiloxane, ie, terminal alkoxy group having a Mw of 2,000 to 100,000 and having a three-dimensional network structure It is a mixture of polyorganosiloxane.

  The mixing ratio of the component (A1) and the component (A2) is such that the whole component (A) is 100 parts by mass, the component (A1) is 20 to 95 parts by mass, and the component (A2) is 80 to 5 parts by mass. . When the blending amount of the component (A1) is less than 20 parts by mass and the blending amount of the component (A2) exceeds 80 parts by mass, a cured film having sufficiently good scratch resistance cannot be obtained. Moreover, when the compounding quantity of (A2) component is less than 5 mass parts and the compounding quantity of (A1) component exceeds 95 mass parts, it is difficult to obtain the composition which can be used as a coating material without a solvent. The blending ratio of the component (A1) and the component (A2) is preferably such that the component (A1) is 30 to 90 parts by mass and the component (A2) is 70 to 10 parts by mass, and the component (A1) is 40 to 80 parts by mass. More preferably, the component (A2) is in the range of 60 to 20 parts by mass.

[(B) Organometallic compound]
In the room temperature curable polyorganosiloxane composition of the present invention, the organometallic compound as component (B) is composed of (A1) component and (A2) component (A) component (polyorganosiloxane mixture) alkoxy groups, And / or a curing catalyst for reacting an alkoxy group of the component (A) and an alkoxy group of a crosslinking agent (C) described later in the presence of moisture to form a crosslinked structure.

(B) As an organometallic compound that is a curing catalyst,
Carboxylic acid metal salts such as iron octoate, cobalt octoate, manganese octoate, zinc octoate, tin naphthenate, tin caprylate, tin oleate;
Organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin oleate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dioctyltin dilaurate;
Tetraethoxy titanium, tetrapropoxy titanium, tetrabutoxy titanium, diisopropoxy-bis (ethyl acetoacetate) titanium, diisopropoxy-bis (methyl acetoacetate) titanium, diisopropoxy-bis (acetylacetone) titanium, dibutoxy-bis ( Organic titanium compounds such as ethyl acetoacetate) titanium and dimethoxy-bis (ethyl acetoacetate) titanium;
Organic zirconium compounds such as tetrapropoxyzirconium, tetrabutoxyzirconium, tetra (acetylacetic acid) zirconium, tributoxy (acetylacetic acid) zirconium, dibutoxy-bis (ethylacetoacetate) zirconium, 2-ethylhexanoic acidzirconium, tributoxystearic acidzirconium ;
Triethoxyaluminum, triisopropoxyaluminum, diisopropoxy-monosecondary butoxyaluminum, trisecondary butoxyaluminum, diisopropoxy-ethylaluminum acetoacetate, tris (ethylacetoacetate) aluminum, aluminum oxide isopropoxide trimer, aluminum oxide octyl Examples thereof include aluminum compounds such as cyclic oligomers such as rate trimers and aluminum oxide stearate trimers.

These organometallic compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them.
In the room temperature curable polyorganosiloxane composition, conventionally, an organic tin compound such as dibutyltin dioctoate or dibutyltin dilaurate may be used as a curing catalyst. In the present invention, the curability of the composition ( From the viewpoint of both the speed of curing and the scratch resistance of the cured coating, an organic titanium compound is preferred as the curing catalyst. The use of the organic titanium compound is preferable because a composition having a high catalytic ability and a small amount of impurities can be obtained in the presence of a small amount. Among organic titanium compounds, titanium chelates such as diisopropoxy-bis (ethyl acetoacetate) titanium are particularly preferable.

  (B) The compounding quantity of the organometallic compound which is a component is 0.1-15 mass parts with respect to 100 mass parts of said (A) component, Preferably it is 0.1-10 mass parts. If it is less than 0.1 parts by mass, it will not function sufficiently as a curing catalyst, and it will not only take a long time to cure, but in particular, curing at a deep part far from the contact surface with air will be insufficient. On the other hand, if it exceeds 15 parts by mass, there is no effect corresponding to the blending amount, and it is meaningless and uneconomical. In addition, the storage stability is lowered.

[Other ingredients]
In the embodiment of the present invention, a silane compound represented by the formula: R ⁸ _c Si (OR ⁹ ) _{4 -c} (c1) can be contained as the component (C). This silane compound functions as a crosslinking agent for the base polymer as the component (A).

In the formula (c1), R ⁸ is an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which a part of the hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group, Examples thereof are the same groups as R ⁴ in formula (a21) representing organosiloxane (a21). R ⁸ is preferably a methyl group or a vinyl group, and particularly preferably a methyl group. R ⁹ is an alkyl group or an alkoxy-substituted alkyl group, and examples thereof include the same groups as R ³ in formula (a21) representing the above-described linear polyorganosiloxane (a21). R ⁹ is preferably a methyl group or an ethyl group. In the formula (c1), c is 0, 1 or 2.

  Examples of the silane compound (c1) include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetra Examples include propoxysilane, tetraisopropoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, vinylmethyldimethoxysilane, and dimethyldiethoxysilane. These silane compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As a silane compound (c1) which is a crosslinking agent, it is easy to synthesize, does not impair the storage stability of the composition, has little corrosiveness to metals, and provides a high crosslinking reaction rate, that is, a curing rate. It is preferable to use tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, vinylmethyldimethoxysilane, dimethyldiethoxysilane, and particularly preferably methyltrimethoxysilane.

  (C) When mix | blending a silane compound, the compounding quantity is 15 mass parts or less with respect to 100 mass parts of said (A) component, Preferably it is 1-10 mass parts. When the compounding quantity of (C) component exceeds 15 mass parts, the shrinkage rate in the case of hardening will become large, and the physical property after hardening will fall. In addition, the curing rate is remarkably slow, which is economically disadvantageous.

  In the room temperature curable polyorganosiloxane composition of the embodiment, an isocyanurate compound such as tris (N-trialkoxysilylpropyl) isocyanurate can be blended as an adhesiveness imparting agent. Examples of the isocyanurate compound include 1,3,5-tris (N-trimethoxysilylpropyl) isocyanurate. From the viewpoint of compatibility with the composition, the amount of such an adhesion-imparting agent is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of component (A).

  In addition, the room temperature curable polyorganosiloxane composition of the embodiment includes inorganic fillers, pigments, thixotropy imparting agents, viscosity modifiers for improving extrusion workability, which are usually blended in this type of composition, Various additives such as ultraviolet absorbers, fungicides, heat resistance improvers, flame retardants and the like can be blended as necessary within a range not impairing the effects of the present invention.

  Examples of inorganic fillers include fumed silica, calcined silica, precipitated silica, fumed titanium, and those whose surfaces have been hydrophobized with organochlorosilanes, polyorganosiloxanes, hexamethyldisilazane, etc. . In addition, calcium carbonate, organic acid surface-treated calcium carbonate, diatomaceous earth, ground silica, aluminosilicate, magnesia, alumina, and the like can be used. When mix | blending an inorganic filler, 100 mass parts or less are preferable with respect to 100 mass parts of (A) component, and, as for the compounding quantity, 50 mass parts or less are more preferable.

  In the room temperature curable polyorganosiloxane composition of the embodiment, the component (A) and the component (B), and the component (C) and the components described above are mixed in a state where moisture is blocked. Can be obtained. The obtained composition has a viscosity of 20 mPa · s to 1,000 mPa · s at 23 ° C. The viscosity is preferably 20 mPa · s to 500 mPa · s. In addition, the room temperature curable polyorganosiloxane composition of the embodiment does not contain a solvent. Therefore, a solvent removal step is not required at the time of forming the cured film, and volatilization of the solvent does not cause deterioration of the working environment, and corrosion / deterioration of electric / electronic components and circuit boards on which they are mounted.

  The room temperature curable polyorganosiloxane composition obtained above is stored as it is in a sealed container and is used only as a so-called one-packaging room temperature curable composition which is cured only by exposure to moisture in the air during use. Can do. Moreover, the room temperature curable polyorganosiloxane composition of the embodiment is prepared separately, for example, separately from the component (A) and the crosslinking agent as the component (C) and the curing catalyst as the component (B). It can also be used as a so-called multi-packaging room temperature curable composition that is stored separately in separate containers and mixed at the time of use. In addition, the order of mixing of each component is not specifically limited.

  Since the room temperature curable polyorganosiloxane composition of the present invention has a sufficiently low viscosity of 20 mPa · s to 1,000 mPa · s at 23 ° C. as described above, it has good coating properties and should be diluted with a solvent. And can be applied by a normal coating method. The coating film is rapidly cured at room temperature by coming into contact with moisture in the air. The hardness (Type A) of the cured film is as high as 50 or more, and it has excellent electrical and mechanical properties, particularly scratch resistance. Further, even in a long-term test under severe conditions, the cured coating formed on the substrate is free from cracks, blisters, peeling, etc., and the adhesion durability is good.

  Therefore, the room temperature curable polyorganosiloxane composition of the present invention is useful for applications such as coating materials and potting materials for electric and electronic devices, and particularly, electric and electronic parts such as conformal coating agents and the like mounted thereon. It is suitable for use for protecting the surface of the circuit board. Specifically, for example, a wiring board in which electrodes and wirings made of ITO, copper, aluminum, silver, gold, etc. are formed on a board made of epoxy resin, phenol resin, polyimide resin, etc. or a board made of ceramic such as alumina. In addition, it is suitably used as a coating material for electrodes, wiring, and the like in electrical and electronic equipment equipped with semiconductor devices such as ICs, electronic components such as resistors and capacitors.

  When using the room temperature curable polyorganosiloxane composition of the present invention as a wiring board electrode or wiring coating material, as a coating method, a dipping method, a brush coating method, a spray method, a dispensing method, etc. can be used, The thickness of the coating layer is usually 0.01 to 3 mm, preferably 0.05 to 2 mm. If the thickness is less than 0.01 mm, scratch resistance may not be sufficiently obtained. On the other hand, if the thickness exceeds 3 mm, not only the effect can be obtained, but also it takes time to harden the inside, which is uneconomical.

  Next, the electric / electronic device of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of an electric / electronic device according to the present invention.

  The electric / electronic device 1 according to the embodiment includes a wiring board 2 in which a wiring 2b made of a conductor such as a copper foil is formed on an insulating board 2a such as a glass epoxy board. An electrical / electronic component such as an IC package 3 or a capacitor 4 is mounted at a predetermined position on one main surface of the wiring board 2 and is electrically connected to the wiring 2b. The connection between the IC package 3 or the capacitor 4 and the wiring 2b is such that the lead terminals 3a and 4a of these components are inserted into the component holes (not shown) of the wiring substrate 2 and are joined via solder or the like. It is done by doing.

  A cured film 5 made of a cured product of the above-described room temperature curable polyorganosiloxane composition of the present invention is formed on the component mounting surface of the wiring board 2 so as to cover the upper surfaces of the IC package 3 and the capacitor 4. Yes.

  In the electrical / electronic device 1 of such an embodiment, the wiring board 2 and the electrical / electronic components mounted on the main surface thereof are covered with the cured coating 5 that has excellent scratch resistance and is less likely to be peeled off or turned up due to friction. So it is highly reliable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but these examples do not limit the scope of the present invention.

In the following description, a D unit, a T unit, a ^DOM unit, and a ^MOM unit each represent a siloxane unit represented by the following formula.
D unit ………… (CH ₃ ) ₂ SiO _2/2
T unit ………… (CH ₃ ) SiO _3/2
D ^OM unit ............ (CH ₃ ) (OCH ₃ ) SiO _2/2
^MOM unit ………… (CH ₃ ) (OCH ₃ ) ₂ SiO _1/2
In addition, “part” means “part by mass”, “%” means “% by mass”, and all viscosities are values at 23 ° C. and relative humidity 50%. Moreover, a weight average molecular weight (Mw) is the value which measured and measured polystyrene using the gel permeation chromatography (GPC) apparatus (Tosoh Corporation make, apparatus name; HLC-8220 GPC) which uses toluene as a solvent. Furthermore, the nonvolatile content (mass%) is a value measured under heating conditions of 105 ° C. × 1 hour.

  As the component (A1) used in the examples, polyorganosiloxanes (A1-1) to (A1-11) having a three-dimensional network structure having an alkoxy group at the terminal were synthesized as follows.

Synthesis Example 1 (Synthesis of (A1-1))
A 5 L separable flask was charged with 1410 g of toluene and 135 g of methanol, and a mixture of 1107 g of methyltrimethoxysilane, 40 g of methyltrichlorosilane and 433 g of dimethyldimethoxysilane was added with stirring. And after raising the temperature in a flask to 35 degreeC using the mantle heater, 510 g of city water was dripped in the flask. The liquid temperature after completion of the dropwise addition was raised to 60 ° C. After heating and refluxing for 2 hours, 510 g of city water was further added for liquid separation, and the upper water / methanol / HCL layer was discarded.

After dehydrating the lower resin / toluene layer at normal pressure, excess toluene was removed by vacuum stripping to make the nonvolatile content 50%. After filtration, 780 g of polyorganosiloxane (A1-1a) having a silanol group at the end and a three-dimensional network structure was obtained. Mw of the polyorganosiloxane (A1-1a) was 7780. When the composition and structure of the obtained polyorganosiloxane (A1-1a) were examined using ¹ H-NMR and ²⁹ Si-NMR, the D unit represented by the formula: (CH ₃ ) ₂ SiO _2/2 And the formula: (CH ₃ ) _1.3 (OH) _0.16 SiO _{2.4 / 2} and an average composition composed of T0 units, and the molar ratio of each unit is D: T0 = 2. 9: 7.1. It was found to be a polyorganosiloxane having a three-dimensional network structure.

  Next, 1000 g of a 50% toluene solution of a polyorganosiloxane (A1-1a) having a three-dimensional network structure having silanol groups at the ends obtained above was charged into a 2 L separable flask, and both ends having a viscosity of 30 mPa · s. Was added with 214 g of linear polydimethylsiloxane (Mw2900) blocked with silanol groups, and toluene was distilled off by heating under reduced pressure. Next, 556 g of methyltrimethoxysilane was added, 10.6 g of diisobutylamine and 3.8 g of formic acid were added while stirring, and the mixture was stirred at room temperature for 5 minutes, and then the temperature in the flask was raised to 40 ° C. Stirring was performed for a minute. Next, the temperature in the flask was raised to 80 ° C., and the mixture was stirred for 30 minutes. Demethanol reaction of the polyorganosiloxane (A1-1a) and silanol groups of both ends silanol-blocked linear polydimethylsiloxane and methyltrimethoxysilane occurred, and methanol was by-produced. By-product methanol was removed from the flask using a drain tube. After stirring with heating at 80 ° C. for 6 hours, the mixture was cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-1) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-1) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.34 (OCH ₃ ) _0.18 It was found to be a polyorganosiloxane having a three-dimensional network structure with _SiO.1.24 . Further, the viscosity of the polyorganosiloxane (A1-1) was 423 mPa · s, and Mw was 8,800.
From these data, it is estimated that polyorganosiloxane (A1-1) has a unit formula: (D ₃₁ T ₇₆ ) (D ₃₈ ) _0.35 (D ^OM ) _0.34 (M ^OM ) ₁₂ . The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.58.

Synthesis Example 2 (Synthesis of (A1-2))
A 5 L separable flask was charged with 1410 g of toluene and 135 g of methanol, and a mixture of 1208 g of methyltrimethoxysilane, 20 g of methyltrichlorosilane, and 361 g of dimethyldimethoxysilane was added with stirring. And operation similar to the synthesis example 1 was performed, and the polyorganosiloxane (A1-2a) of the three-dimensional network structure which has a silanol group at the terminal was obtained. Mw of the polyorganosiloxane (A1-2a) was 4500.

  Next, 200 g of a 50% toluene solution of a polyorganosiloxane (A1-2a) having a three-dimensional network structure having silanol groups at the ends obtained above was charged into a 1 L separable flask, and both ends having a viscosity of 30 mPa · s. Was added 43 g of linear polydimethylsiloxane (Mw2900) blocked with silanol groups, and toluene was distilled off by heating and vacuum stripping. Next, 113 g of methyltrimethoxysilane was added, 2.2 g of diisobutylamine and 0.75 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was performed in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain a polyorganosiloxane (A1-2) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-2) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.33 (OCH ₃ ) _0.19 It was found to be a polyorganosiloxane having a three-dimensional network structure with _SiO.1.24 . The viscosity of the polyorganosiloxane (A1-2) was 265 mPa · s, and Mw was 5400.
From these data, polyorganosiloxane (A1-2) has the unit formula: (D _15.6 T _49.4 ) (D ₄₀ ) _0.33 (D ^OM ) _0.3 (M ^OM ) _7.8 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.58.

Synthesis Example 3 (Synthesis of (A1-3))
400 g of a 50% toluene solution of a polyorganosiloxane (A1-2a) having a silanol group at the end and having a silanol group obtained in the same manner as in Synthesis Example 2 was charged into a 1 L separable flask, and the viscosity was 10 mPa · s. 43 g of linear polydimethylsiloxane (Mw910) blocked at both ends with silanol groups was added, and toluene was distilled off by heating under reduced pressure. Next, 113 g of methyltrimethoxysilane was added, 2.2 g of diisobutylamine and 0.75 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was performed in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-3) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-3) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.33 (OCH ₃ ) _0.18 It was found to be a polyorganosiloxane having a three-dimensional network structure with SiO 2 _.1.25 . The viscosity of the polyorganosiloxane (A1-3) was 210 mPa · s, and Mw was 4680.
From these data, the polyorganosiloxane (A1-3) has the unit formula: (D _13.5 T _42.6 ) (D ₁₂ ) _0.91 (D ^OM ) _0.9 (M ^OM ) ₆ Presumed. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.57.

Synthesis Example 4 (Synthesis of (A1-4))
400 g of a 50% toluene solution of a polyorganosiloxane (A1-2a) having a three-dimensional network structure having a silanol group at the end, obtained in the same manner as in Synthesis Example 2, was used. Then, instead of both ends silanol group-blocked linear polydimethylsiloxane (Mw910) having a viscosity of 10 mPa · s, linear polydimethylsiloxane (Mw7400) having both ends having a viscosity of 70 mPa · s blocked with silanol groups is used. A polyorganosiloxane (A1-4) having a terminal blocked with a methoxysilyl group was obtained in the same manner as in Synthesis Example 3 except that it was used.

When the composition and structure of the polyorganosiloxane (A1-4) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.31 (OCH ₃ ) _0.19 it was found that a polyorganosiloxane of three-dimensional network structure having a SiO _.1.25. Further, the viscosity of the polyorganosiloxane (A1-4) was 280 mPa · s, and Mw was 5710.
From these data, the polyorganosiloxane (A1-4) has the unit formula: (D _16.7 T _52.7 ) (D ₁₀₀ ) _0.1 (D ^OM ) _0.1 (M ^OM ) _8.2 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.51.

Synthesis Example 5 (Synthesis of (A1-5))
In a mixture of methyltrimethoxysilane, methyltrichlorosilane and dimethyldimethoxysilane (hereinafter referred to as a silane mixture), methyltrimethoxysilane and methyltrichlorosilane which are T unit sources, and dimethyldimethoxysilane which is a D unit source The polyorgano has a three-dimensional network structure having a silanol group at the terminal in the same manner as in Synthesis Example 1, with a molar ratio of 8: 2 (the molar ratio of methyltrimethoxysilane and methyltrichlorosilane is 1000: 7). 800 g of siloxane (A1-5a) was obtained. The Mw of this polyorganosiloxane (A1-5a) was 4800.

  Next, a 2 L separable flask was charged with 800 g of a 50% toluene solution of a polyorganosiloxane (A1-5a) having a three-dimensional network structure having silanol groups at the ends obtained above, and both ends having a viscosity of 30 mPa · s. 400 g of silanol group-blocked linear polydimethylsiloxane (Mw2900) was added, and toluene was distilled off by heating under reduced pressure. Next, 450 g of methyltrimethoxysilane was added, 8.6 g of diisobutylamine and 3.0 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was carried out in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-5) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-5) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.47 (OCH ₃ ) _0.18 It was found to be a polyorganosiloxane having a three-dimensional network structure with SiO 1 _.18 . The polyorganosiloxane (A1-5) had a viscosity of 420 mPa · s and Mw of 6900.
From these data, polyorganosiloxane (A1-5) has the unit formula: (D _14.8 T _62.6 ) (D ₄₀ ) _1.31 (D ^OM ) _1.29 (M ^OM ) _12.4 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 1.07.

Synthesis Example 6 (Synthesis of (A1-6))
In the silane mixture, the molar ratio of methyltrimethoxysilane and methyltrichlorosilane which are T unit sources to dimethyldimethoxysilane which is a D unit source is 8: 2 (the molar ratio of methyltrimethoxysilane and methyltrichlorosilane is 1000: 7), and in the same manner as in Synthesis Example 1, 786 g of polyorganosiloxane (A1-6a) having a three-dimensional network structure having a silanol group at the terminal was obtained. The Mw of this polyorganosiloxane (A1-6a) was 10380.

  Next, a 2 L separable flask was charged with 800 g of a 50% toluene solution of a polyorganosiloxane (A1-6a) having a three-dimensional network structure having silanol groups at the ends obtained above, and both ends having a viscosity of 30 mPa · s. 173 g of silanol group-blocked linear polydimethylsiloxane (Mw2900) was added, and toluene was distilled off by heating under reduced pressure. Next, 450 g of methyltrimethoxysilane was added, 8.6 g of diisobutylamine and 3.0 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was carried out in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-6) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-6) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.59 (OCH ₃ ) _0.18 It was found to be a polyorganosiloxane having a three-dimensional network structure with SiO 1 _.12 . The viscosity of this polyorganosiloxane (A1-6) was 520 mPa · s, and Mw was 14,500.
From these data, the polyorganosiloxane (A1-6) is estimated to have the unit formula: (D _29.8 T ₁₂₀ ) (D ₄₀ ) _4.8 (D ^OM ) _4.7 (M ^OM ) ₃₁ The The molar ratio (D / T) between the D unit and the T unit in this unit formula is 1.85.

Synthesis Example 7 (Synthesis of (A1-7))
In the silane mixture, the molar ratio of methyltrimethoxysilane and methyltrichlorosilane which are T unit sources to dimethyldimethoxysilane which is a D unit source is 9: 1 (the molar ratio of methyltrimethoxysilane and methyltrichlorosilane is 1000: 7), and in the same manner as in Synthesis Example 1, 765 g of a polyorganosiloxane (A1-6a) having a three-dimensional network structure having a silanol group at the terminal was obtained. The Mw of this polyorganosiloxane (A1-7a) was 4780.

  Next, a 2 L separable flask was charged with 800 g of a 50% toluene solution of a polyorganosiloxane (A1-7a) having a three-dimensional network structure having silanol groups at the ends obtained above, and both ends having a viscosity of 30 mPa · s. 400 g of silanol group-blocked linear polydimethylsiloxane (Mw2900) was added, and toluene was distilled off by heating under reduced pressure. Next, 450 g of methyltrimethoxysilane was added, 8.6 g of diisobutylamine and 3.0 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was carried out in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-7) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-7) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.37 (OCH ₃ ) _0.19 it was found that a polyorganosiloxane of three-dimensional network structure having a SiO _.1.22. The viscosity of this polyorganosiloxane (A1-7) was 172 mPa · s, and Mw was 6400.
From these data, polyorganosiloxane (A1-7) has the unit formula: (D _8.1 T _65.6 ) (D ₄₀ ) _0.92 (D ^OM ) _0.89 (M ^OM ) _11.2 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.68.

Synthesis Example 8 (Synthesis of (A1-8))
In the silane mixture, only methyltrimethoxysilane and methyltrichlorosilane which are T unit sources were used, and the reaction was carried out in the same manner as in Synthesis Example 1. The molar ratio of methyltrimethoxysilane to methyltrichlorosilane was 1000: 7. Then, 746 g of a polyorganosiloxane (A1-8a) having a three-dimensional network structure having a silanol group at the terminal was obtained. The Mw of this polyorganosiloxane (A1-8a) was 7700.

  Next, a 2 L separable flask was charged with 800 g of a 50% toluene solution of a polyorganosiloxane (A1-8a) having a three-dimensional network structure having silanol groups at the ends obtained above, and both ends having a viscosity of 30 mPa · s. 400 g of silanol group-blocked linear polydimethylsiloxane (Mw2900) was added, and toluene was distilled off by heating under reduced pressure. Next, 450 g of methyltrimethoxysilane was added, 8.6 g of diisobutylamine and 3.0 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was carried out in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-8) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-8) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.41 (OCH ₃ ) _0.19 It was found to be a polyorganosiloxane having a three-dimensional network structure with SiO 2 _.1.2 . The viscosity of this polyorganosiloxane (A1-8) was 440 mPa · s, and Mw was 10380.
From these data, it is estimated that polyorganosiloxane (A1-8) has the unit formula: T ₁₁₄ (D ₄₀ ) _2.4 (D ^OM ) _2.3 (M ^OM ) ₂₁ . In this unit formula, the molar ratio (D / T) between the D unit and the T unit is 0.84.

Synthesis Example 9 (Synthesis of (A1-9))
In the silane mixture, the molar ratio of methyltrimethoxysilane and methyltrichlorosilane which are T unit sources to dimethyldimethoxysilane which is a D unit source is 5: 5 (the molar ratio of methyltrimethoxysilane to methyltrichlorosilane is 1000: 7) In the same manner as in Synthesis Example 1, 776 g of polyorganosiloxane (A1-9a) having a three-dimensional network structure having a silanol group at the terminal was obtained. The Mw of this polyorganosiloxane (A1-9a) was 2010.

  Next, a 2 L separable flask was charged with 800 g of a 50% toluene solution of a polyorganosiloxane (A1-9a) having a three-dimensional network structure having silanol groups at the ends obtained above, and both ends having a viscosity of 30 mPa · s. 172 g of silanol group-blocked linear polydimethylsiloxane (Mw2900) was added, and toluene was distilled off by heating under reduced pressure. Next, 450 g of methyltrimethoxysilane was added, 8.6 g of diisobutylamine and 3.0 g of formic acid were added with stirring, and a methanol removal reaction between a silanol group and methyltrimethoxysilane was carried out in the same manner as in Synthesis Example 1. Byproduct methanol was removed. The mixture was further stirred at 80 ° C. for 6 hours and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-9) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-9) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.46 (OCH ₃ ) _0.2 It was found to be a polyorganosiloxane having a three-dimensional network structure with _SiO.1.17 . The viscosity of this polyorganosiloxane (A1-9) was 113 mPa · s, and Mw was 2200.
These data polyorganosiloxane (A1-9) are unit _formula: is presumed to have a ^{_{(D 13.6 T 13) (M}} OM) 2.9. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 1.05.

Synthesis Example 10 (Synthesis of (A1-10))
200 g of a 50% toluene solution of a polyorganosiloxane (A1-2a) having a silanol group at the end and having a silanol group obtained in the same manner as in Synthesis Example 2 was charged into a 1 L separable flask, and methyltrimethoxysila 73 g was added, 1.4 g of diisobutylamine and 0.48 g of formic acid were added with stirring, and the mixture was stirred at room temperature for 5 minutes. Next, the temperature in the flask was raised to 40 ° C. and heated and stirred for 30 minutes, and then the temperature in the flask was raised to 80 ° C. and heated and stirred for 30 minutes. Demethanol reaction between silanol groups and methyltrimethoxysilane occurred, and methanol was by-produced. By-product methanol was removed from the flask using a drain tube. Furthermore, after heating and stirring at 80 ° C. for 4 hours, the mixture was cooled to room temperature.

  Next, 43 g of linear polydimethylsiloxane (Mw2900) blocked with silanol groups at both ends with a viscosity of 30 mPa · s was added, 40 g of methyltrimethoxysilane was further added, and 0.8 g of diisobutylamine and 0.27 g of formic acid were added while stirring. After stirring at room temperature for 5 minutes, the temperature in the flask was raised to 40 ° C. and heated and stirred for 30 minutes. Next, the temperature in the flask was raised to 80 ° C., and the mixture was stirred for 30 minutes. Demethanol reaction between silanol groups and methyltrimethoxysilane occurred, and methanol was by-produced. By-product methanol was removed from the flask using a drain tube. Furthermore, after stirring for 4 hours at 80 ° C., it was confirmed by IR spectrum measurement that the absorption peak of the silanol group had disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure, and toluene was distilled off by heating and vacuum stripping. In this way, polyorganosiloxane (A1-10) whose end was blocked with a methoxysilyl group was obtained.

When the composition and structure of the polyorganosiloxane (A1-10) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.33 (OCH ₃ ) _0.18 It was found to be a polyorganosiloxane having a three-dimensional network structure with _SiO.1.24 . The viscosity of the polyorganosiloxane (A1-10) was 298 mPa · s, and Mw was 5380.
From these data, polyorganosiloxane (A1-10) has the unit formula: (D _15.6 T _49.3 ) (D ₄₀ ) _0.32 (D ^OM ) _0.31 (M ^OM ) _7.7 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.58.

Synthesis Example 11 (Synthesis of (A1-11))
200 g of a 50% toluene solution of a polyorganosiloxane (A1-2a) having a silanol group at the end and having a silanol group obtained in the same manner as in Synthesis Example 2 was charged into a 1 L separable flask, and a viscosity of 30 mPa · s. After adding 45 g of linear polydimethylsiloxane (Mw: 3300) blocked at both ends with methyldimethoxysilyl group, 1.1 g of diisobutylamine and 0.38 g of formic acid were added with stirring, and 5 g at room temperature. Stirring was performed for a minute. Next, the temperature in the flask was raised to 40 ° C. and heated and stirred for 30 minutes, and then the temperature in the flask was raised to 80 ° C. and heated and stirred for 30 minutes. A methanol removal reaction occurred between the methoxy group of the methyldimethoxysilyl group and the silanol group, and methanol was by-produced. By-product methanol was removed from the flask using a drain tube. The mixture was further heated and stirred at 80 ° C. for 6 hours, and then cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, low boiling point substances were distilled out of the system by distillation under reduced pressure to obtain polyorganosiloxane (A1-11) whose ends were blocked with methoxysilyl groups.

When the composition and structure of the polyorganosiloxane (A1-11) thus obtained were examined by ¹ H-NMR and ²⁹ Si-NMR, the average composition formula: (CH ₃ ) _1.4 (OCH ₃ ) _0.14 It was found to be a polyorganosiloxane having a three-dimensional network structure with SiO _1.23 . The viscosity of this polyorganosiloxane (A1-11) was 312 mPa · s, and Mw was 5980.
From these data, polyorganosiloxane (A1-11) has the unit formula: (D _17.7 T _55.9 ) (D ₄₀ ) _0.61 (D ^OM ) _0.59 (M ^OM ) _7.3 Presumed to have. The molar ratio (D / T) between the D unit and the T unit in this unit formula is 0.75.

Synthesis Example 12 (Synthesis of (A2-7))
A terminal trimethylsilyl group-blocked polymethylsiloxane (A2-7) having a three-dimensional network structure used in the comparative example was synthesized as follows.

  1300 g of water was charged into a 3 L separable flask, and a mixture of 410 g of dimethyldichlorosilane, 123 g of methyltrichlorosilane and 16 g of trimethylchlorosilane was dropped into the flask while stirring.

  Next, the lower hydrochloric acid layer was removed using a separatory funnel, 650 g of water and 20 g of sodium chloride were further added and stirred, and then the sodium chloride layer was removed and filtered. Thus, 800 g of a polyorganosiloxane having a three-dimensional network structure having a terminal silanol group was obtained. Next, terminal methoxylation reaction of the obtained polyorganosiloxane was performed.

  A 1 L separable flask was charged with 200 g of a polyorganosiloxane having a silanol group at the end and having a three-dimensional network structure and 50 g of methyltrimethoxysilane, stirred for 5 minutes at room temperature, and then stirred. , 0.76 g of formic acid was added into the flask. Thereafter, the temperature in the flask was raised to 80 ° C., followed by stirring with heating. After 30 minutes, the methanol removal reaction between the silanol group and methyltrimethoxysilane started, and methanol was by-produced. By-product methanol was removed from the flask using a drain tube. After heating and stirring at 80 ° C. for 24 hours, the mixture was cooled to room temperature. And it was confirmed by IR spectrum measurement that the absorption peak of the silanol group disappeared. Subsequently, excess methyltrimethoxysilane was distilled out of the system by distillation under reduced pressure.

Thus, when the composition and structure of the resulting polyorganosiloxane (A2- ^7), were examined in 1 H-NMR and ²⁹ Si-NMR, the _{formula: (CH 3)} 3 M units represented by _{SiO 1/2} And an average composition comprising a D unit represented by the formula: (CH ₃ ) ₂ SiO _2/2 and a T unit represented by the formula: (CH ₃ ) (OCH ₃ ) _0.2 SiO _{2.8 / 2} It was found that the polyorganosiloxane has a three-dimensional network structure in which the molar ratio of each unit is M: D: T = 1: 19: 5. The viscosity of the resulting polyorganosiloxane (A2- 7) is 40 mPa · s, Mw was 2,700.

[Example 1]
A linear polydimethylsiloxane (viscosity 10 mPa · s) in which 85.7 parts of the polyorganosiloxane (A1-1) obtained in Synthesis Example 1 was blocked with (A2-1) both ends of the molecular chain with methyldimethoxysilyl groups. s) 7.15 parts, (A2-2) 7.15 parts of linear polydimethylsiloxane (viscosity 100 mPa · s) in which both ends of the molecular chain are blocked with methyldimethoxysilyl groups, (C1) methyltrimethoxysilane 5 parts, 2 parts of (B1) diisopropoxy-bis (ethyl acetoacetate) titanium, and 0.2 part of 1,3,5-tris (N-trimethoxysilylpropyl) isocyanurate were blended, and under moisture blocking To obtain a polyorganosiloxane composition.

[Examples 2 to 18]
The components shown in Table 1 and Table 2 were blended in the compositions shown in the same table and mixed in the same manner as in Example 1 to obtain a polyorganosiloxane composition.

[Comparative Examples 1 to 11]
The components shown in Table 3 and Table 4 were blended in the compositions shown in the same table and mixed in the same manner as in Example 1 to obtain a polyorganosiloxane composition.

  In Tables 1 to 4, the polyorganosiloxanes described by abbreviations (A1-12) to (A1-16) are shown below. All of these, as well as appropriately changing the molar ratio of methyltrimethoxysilane, methyltrichlorosilane, and dimethyldimethoxysilane, which are starting materials, have both ends silanol group-blocked linear polydimethylsiloxane and methyltrimethoxysilane having a viscosity of 30 mPa · s. And the molar ratio (D / T) between the D unit and the T unit in the unit formula is less than 0.5. It has become.

(A1-12) is a polyorganosiloxane having a three-dimensional network structure having an average composition formula: (CH ₃ ) _1.26 (OCH ₃ ) _0.2 SiO _1.2.27 , and a unit formula: (D _{30. 4} T _74.5 ) (M ^OM ) _11.5 . Mw is 8540, and the molar ratio (D / T) between the D unit and the T unit in the unit formula is 0.41.
(A1-13) is a polyorganosiloxane having a three-dimensional network structure having an average composition formula: (CH ₃ ) _1.21 (OCH ₃ ) _0.21 SiO _1.29 , and a unit formula: (D _{14. 6} T _48.3 ) (M ^OM ) _7.4 . Mw is 5150, and the molar ratio (D / T) between D units and T units in the unit formula is 0.30.
(A1-14) is a polyorganosiloxane having a three-dimensional network structure having an average composition formula: (CH ₃ ) ₁ (OCH ₃ ) _0.22 SiO _.1.39 , and unit formula: T ₁₁₉ (M ^OM ) ₁₅ Mw is 9650, and the molar ratio (D / T) between the D unit and the T unit in the unit formula is 0.
(A1-15) is a polyorganosiloxane having a three-dimensional network structure having an average composition formula: (CH ₃ ) _1.18 (OCH ₃ ) _0.21 SiO _.1.31 , and a unit formula: (D _{29. 1} T _116.5 ) (M ^OM ) _17.1 . Mw is 11890, and the molar ratio (D / T) of D units to T units in the unit formula is 0.25.
(A1-16), the average composition _{formula: (CH 3) 1.1 (OCH} 3) a polyorganosiloxane of the three-dimensional network structure having a 0.22 SiO _.1.34, unit formula: _{(D 7.} with a ^{_{2 T 58.1) (M OM)}} 8.07. Mw is 5340, and the molar ratio (D / T) of D unit to T unit in the unit formula is 0.12.

In Tables 1 to 4, the polyorganosiloxanes described by abbreviations (A2-3) to (A2-8) are shown below.
(A2-3) indicates a linear polydimethylsiloxane (viscosity 800 mPa · s) in which both ends are blocked with methyldimethoxysilyl groups.
(A2-4) represents a linear polydimethylsiloxane (viscosity 15 mPa · s) in which both ends are blocked with trimethoxysilyl groups.
(A2-5) represents a linear polydimethylsiloxane (viscosity: 110 mPa · s) in which both ends are blocked with a trimethoxysilyl group.
(A2-6) represents linear polydimethylsiloxane (viscosity 1000 mPa · s) having both ends blocked with trimethoxysilyl groups.
(A2-7) represents a polyorganosiloxane having a viscosity of 40 mPa · s and having a Mw of 2,700 and having a three-dimensional network structure obtained in Synthesis Example 12.
(A2-8) represents a partially hydrolyzed condensate of methyltrimethoxysilane (viscosity 20 mPa · s, Si number 8).

  About the polyorganosiloxane composition obtained in Examples 1-18 and Comparative Examples 1-11, various characteristics were measured and evaluated by the method shown below. These results together with the composition are shown in Table 1 for Examples 1 to 9, Table 2 for Examples 10 to 18, Table 3 for Comparative Examples 1 to 6, and Table 4 for Comparative Examples 7 to 11. Each is shown.

[viscosity]
The viscosity of the polyorganosiloxane composition was measured according to JIS K6249. A rotational viscometer (manufactured by Shibaura Semtec Co., Ltd., product name: Bismetron VDA-2) was used, and the rotational speed was 30 rpm. Measurements were taken at 2.

[Tack Free Time]
The tack free time of the polyorganosiloxane composition was measured according to JIS K6249. The sample was placed flat in an aluminum petri dish so that bubbles did not enter (the thickness of the sample was 3 mm), and then the surface was lightly touched with a fingertip washed with ethyl alcohol. The time when the sample did not adhere to the fingertip was defined as the tack free time (minutes).

[hardness]
The hardness of the polyorganosiloxane composition was measured as shown below according to JIS K6249. That is, after the polyorganosiloxane composition was formed into a sheet having a thickness of 2 mm, it was allowed to cure at 23 ° C. and 50% RH for 3 days. Next, three of the obtained cured sheets were stacked, and the hardness was measured with a durometer (Type A) and a micro hardness meter (manufactured by Polymer Instruments Co., Ltd., product name: M-250).

[Hardness change]
Changes in hardness after standing in an atmosphere of 85 ° C. and 85% RH for 500 hours and in an atmosphere of 150 ° C. for 500 hours were measured with a micro hardness meter.

[Scratch resistance]
The polyorganosiloxane composition was applied to a comb-shaped electrode substrate (copper electrode, pattern width 0.316 mm) defined by JIS Z3197 (ISO 9455) at a thickness of 100 μm, and allowed to stand at 23 ° C. and 50% RH for 3 days. And cured. Next, a pencil hardness test was performed on the formed cured film according to JIS K5600-5-4 to evaluate scratch resistance. In the pencil hardness test, 2B and 4B pencils were used, a line was drawn with a load of 750 g, the subsequent state of the cured film was visually observed, and when the cured film was not turned up, it was evaluated as “OK”.

[Adhesion durability]
The polyorganosiloxane composition was applied to the surface of a substrate made of glass epoxy so as to have a length of 50 mm, a width of 10 mm and a thickness of 1 mm, and allowed to cure at 23 ° C. and 50% RH for 3 days. . The cured product thus formed was subjected to (1) standing at 150 ° C. for 500 hours, (2) standing at 85 ° C. and 85% RH for 500 hours, and (3) 100 cycles of −40 ° C. to 150 ° C. thermal cycle. After applying the three conditions of application, the cured product was scraped off from the substrate surface with a metal spatula, and the state of peeling of the cured product at this time was examined. And the adhesion durability was evaluated according to the following criteria.

<Evaluation criteria>
OK: The cured product cannot be peeled off from the interface with the substrate, and the cured product is destroyed.
Peeling: Part of the cured product peels from the interface with the substrate.
Cracks and cracks: A part of the cured product is peeled off from the interface with the base material, and cracks and cracks are generated in a part of the cured product.
Swelling: A part of the cured product swells, and the cured product peels from the interface with the substrate.

  From Table 1 and Table 2, the polyorganosiloxane compositions obtained in Examples 1 to 18 have a uniform viscosity suitable for thin film application, and also have high hardness (Type A and micro hardness) It was found that a cured film excellent in scratch resistance was formed. Also, in the observation of the adhesion and appearance after applying each condition, the cured product was not observed cracks, cracks, blisters, peeling, etc., and the adhesion durability was good.

  On the other hand, as can be seen from Table 3 and Table 4, in Comparative Example 7, a polyorganosiloxane composition having a viscosity suitable for thin film coating was not obtained, and in Comparative Example 9, the cured film was brittle and the hardness and the like Measurement was impossible. Moreover, although the polyorganosiloxane composition obtained in Comparative Examples 5, 6 and 10 had a viscosity capable of thin film coating, the obtained cured film had low hardness and poor scratch resistance. Moreover, although the polyorganosiloxane composition obtained in Comparative Examples 1-4 and 8 has a relatively high hardness of the cured film, the adhesiveness and appearance after applying the above conditions (1) to (3) In the observation, cracks, swelling, peeling, etc. were observed in the cured product, and the adhesion durability was poor. Furthermore, in the polyorganosiloxane composition obtained in Comparative Example 11, cracks and blisters were observed in the cured product after the conditions (1) to (3) were applied, and the adhesion durability was poor.

  The room temperature curable polyorganosiloxane of the present invention is useful for applications such as coating materials and potting materials for electrical and electronic equipment, and in particular, conformal coating agents for electrical and electronic equipment in which electronic components are mounted on a substrate. It is suitable as.

  DESCRIPTION OF SYMBOLS 1 ... Electric / electronic device, 2 ... Wiring board, 3 ... IC package, 4 ... Capacitor, 5 ... Cured film of room temperature curable polyorganosiloxane composition.

Claims (7)

A polyorganosiloxane obtained by an alkoxylation reaction of a silanol group-containing polyorganosiloxane (A1a) containing a bifunctional siloxane unit and a trifunctional siloxane unit, having a silanol group at the terminal and a three-dimensional network structure A bifunctional siloxane unit and a trifunctional siloxane unit are contained so that the molar ratio of the bifunctional siloxane unit to the trifunctional siloxane unit is 0.5 to 2.0 and bonded to a silicon atom. The first polyorganosiloxane (A1) having two alkoxy groups bonded to the terminal silicon atom and having a weight average molecular weight (Mw) of 2,000 to 100,000 is 20 to 95 masses. And
80-5 parts by mass of a second polyorganosiloxane (A2) having two or more alkoxy groups bonded to silicon atoms in the molecule and having a linear shape and a viscosity at 23 ° C. of 3 mPa · s to 500 mPa · s For 100 parts by mass of the mixed polyorganosiloxane mixture (A),
(B) A room temperature-curable polyorganosiloxane composition comprising 0.1 to 15 parts by mass of an organic titanium compound as a curing catalyst. The (A1) first polyorganosiloxane has (A1a) a silanol group-containing polyorganosiloxane having a three-dimensional network structure, has silanol groups at both ends, and has a weight average molecular weight (Mw) of 500 to 10,000. What was obtained by mixing linear silanol group-containing polyorganosiloxane (A1b), adding (A1c) methyltrimethoxysilane to this mixture, and performing an alkoxylation reaction with dealcoholization The room temperature-curable polyorganosiloxane composition according to claim 1, wherein   The (A1) first polyorganosiloxane is a linear polyorganosiloxane having (A1a) a silanol group-containing polyorganosiloxane having a three-dimensional network structure and (A1d) an alkoxy group bonded to a silicon atom at the terminal. 2. The room temperature-curable polyorganosiloxane composition according to claim 1, wherein the composition is obtained by adding siloxane and performing an alkoxylation reaction with dealcoholization. 4. The room temperature-curable polyorganosiloxane according to claim 3, wherein the (A1d) polyorganosiloxane is a linear polyorganosiloxane having two alkoxy groups bonded to silicon atoms at both ends. Composition. Furthermore, the formula: R ⁸ _c Si (OR ⁹ ) _4-c
(In the formula, R ⁸ is an unsubstituted monovalent hydrocarbon group or a monovalent hydrocarbon group in which a part of hydrogen atoms is substituted with a halogen atom or a cyanoalkyl group, and R ⁹ is an alkyl group or an alkyl group. Containing 0.1 to 15 parts by mass of a silane compound (C) represented by an alkoxy-substituted alkyl group in which a part of the hydrogen atoms of the group is substituted with an alkoxy group, and c is 0, 1 or 2. The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 4, wherein the composition is a room temperature curable polyorganosiloxane composition.   The room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 5, which is a composition for coating electrodes and / or wirings of electric / electronic devices.   An electric / electronic device comprising a coating made of a cured product of the room temperature-curable polyorganosiloxane composition according to any one of claims 1 to 6 on the surface of an electrode and / or wiring.

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