JP2022049915A - Composition for low-dielectric-constant and highly heat-resistant substrate - Google Patents

Abstract

To provide a composition capable of forming a low-dielectric substrate which has a low dielectric constant in a high-frequency region and also has high heat resistance.SOLUTION: The composition for a low-dielectric-constant and highly heat-resistant substrate contains a polysiloxane copolymer comprising a repeating unit of a specific cage silsesquioxane (A) and a repeating unit of a specific chain siloxane (B). In the polysiloxane copolymer, the molar ratio of the repeating unit of the cage silsesquioxane (A) to the repeating unit of the chain siloxane (B) is 1:1-1:10. The dielectric constants at 1 GHz and 10 GHz of the polysiloxane copolymer are both 3.0 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a composition for a low dielectric constant and high heat resistant substrate using a siloxane polymer having silanol and a crosslinked product.

With the further increase in speed / wideband transmission of high-speed data communication, it is required to reduce the dielectric constant of the substrate materials of the electronic circuits and antennas used for them.

Furthermore, in transportation equipment such as automobiles, enormous data processing for autonomous driving and cooperation with high-speed communication are becoming stronger, and distance sensors are becoming millimeter-wave radars, which are used there. In addition to the conventional insulating properties, it is important to reduce the dielectric constant of the material (see, for example, Non-Patent Document 1).

In order to reduce the dielectric constant of the resin material, there are various methods such as reducing the portion having a large polarity and reducing the electron transfer, but a method of forming fine bubbles in the resin is also being studied. However, depending on the size of the pores, moisture in the air may be adsorbed, and the dielectric constant may increase under actual usage conditions.

In general, a polymer containing silsesquioxane having a cage-shaped structure has attracted attention from various fields because it has a unique structure and is expected to have a unique effect. In particular, since the inside of a car composed of silicon atoms or the like can be regarded as a cavity, it is attracting attention as a technique for lowering the dielectric constant as in the above-mentioned effect of micropores. As a polymer containing such a silsesquioxane skeleton, a silicon-based polymer having a silsesquioxane skeleton in the main chain is known (see, for example, Patent Document 1).
Further, a silicone film having excellent heat resistance has been developed by introducing a crosslinkable functional group into a silicon compound having a silsesquioxane skeleton having a cage structure in the main chain to form a crosslinkable polymer (for example, Patent Document). 2). On the other hand, many low-dielectric resins obtained by polymerizing polysilsesquioxane having a polymerizing group having various structures including a cage type and a reactive organic monomer have been developed, but the polarities of the bonding group and the organic moiety are high. The advantages of the cage-type silsesquioxane were not fully utilized (see, for example, Patent Documents 3, 4, 5 and 6).

Japanese Unexamined Patent Publication No. 2006-333007 Japanese Unexamined Patent Publication No. 2010-116464 Japanese Unexamined Patent Publication No. 2008-024894 Japanese Unexamined Patent Publication No. 2012-107121 Japanese Unexamined Patent Publication No. 2013-107121 Japanese Unexamined Patent Publication No. 2020-70432

RF World No. 40p. 97 (CQ Publisher, 2017)

As described above, there is a demand for a material for an electronic substrate having a low dielectric constant and high reliability (high heat resistance). There are various methods for this, such as reducing highly polar bond groups and side chains, increasing voids such as fine bubbles, and making it difficult for molecular chains to vibrate due to cross-linking. Low bonding groups are brittle, and fluororesins and the like have advantages and disadvantages such as poor adhesiveness and workability.

The present inventors react a silsesquioxane compound having a cage-type structure with high heat resistance and chemical stability with a compound containing a chain siloxane structure, and at that time, silsesquioxane having a cage-type structure. By optimizing the ratio of the compound to the chain siloxane structure, the dielectric constant at 1 GHz and 10 GHz is both 3 or less, and the weather resistance and heat resistance (1% or 5% weight loss temperature) are extremely high at 350 ° C or higher. We have found that a liquid composition and a film obtained by curing the liquid composition can be formed, and completed the present invention.

式（Ａ）中、
Ｒ^０は独立して、炭素数６～２０のアリールまたは炭素数５～６のシクロアルキルであり、炭素数６～２０のアリールおよび炭素数５～６のシクロアルキルにおいて、少なくとも１つの水素が、ハロゲンまたは炭素数１～２０のアルキルで置き換えられてもよく；
Ｒ^１は独立して、水素、ビニル、アリル、水酸基、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、炭素数７～４０のアリールアルキル、または炭素数１～４０のアルキルであり、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、および炭素数７～４０のアリールアルキル中のアリールにおいて、少なくとも１つの水素がハロゲンまたは炭素数１～２０のアルキルで置き換えられてもよく、炭素数７～４０のアリールアルキル中のアルキレンにおいて、少なくとも１つの水素がハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が、－Ｏ－、－ＣＨ＝ＣＨ－、または炭素数５～２０のシクロアルキレンで置き換えられてもよく、炭素数１～４０のアルキルは、少なくとも１つの水素が、ハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が－Ｏ－または炭素数５～２０のシクロアルキレンで置き換えられてもよく；
ｘは１以上であり；
式（Ｂ）中、
Ｒ^２は独立して、水素、ビニル、アリル、水酸基、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、炭素数７～４０のアリールアルキル、または炭素数１～４０のアルキルであり、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、および炭素数７～４０のアリールアルキル中のアリールにおいて、少なくとも１つの水素がハロゲンまたは炭素数１～２０のアルキルで置き換えられてもよく、炭素数７～４０のアリールアルキル中のアルキレンにおいて、少なくとも１つの水素がハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が、－Ｏ－、－ＣＨ＝ＣＨ－、または炭素数５～２０のシクロアルキレンで置き換えられてもよく、炭素数１～４０のアルキルにおいて、少なくとも１つの水素がハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が－Ｏ－または炭素数５～２０のシクロアルキレンで置き換えられてもよく；
ｙは１以上である。 The composition for a low dielectric constant and high heat resistant substrate according to the first aspect of the present invention is a cage-type silsesquioxane repeating unit represented by the formula (A) and a chain siloxane repeating unit represented by the formula (B). It contains a polysiloxane copolymer composed of a polysiloxane copolymer, and in the polysiloxane copolymer, a cage-type silsesquioxane repeating unit represented by the formula (A) and a chain-shaped siloxane repeating unit represented by the formula (B). The molar ratio of the polysiloxane copolymer is 1: 1 to 1:10, and the dielectric constants of the polysiloxane copolymer at 1 GHz and 10 GHz are both 3 or less.

In formula (A),
^R0 is independently an aryl having 6 to 20 carbon atoms or a cycloalkyl having 5 to 6 carbon atoms, and in the aryl having 6 to 20 carbon atoms and the cycloalkyl having 5 to 6 carbon atoms, at least one hydrogen is contained. It may be replaced with a halogen or an alkyl having 1 to 20 carbon atoms;
^R1 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, or alkyl having 1 to 40 carbon atoms. At least one hydrogen is replaced by a halogen or an alkyl having 1 to 20 carbon atoms in the aryl in an aryl having 6 to 20 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, and an aryl alkyl having 7 to 40 carbon atoms. Alternatively, in the alkylene in the arylalkyl having 7 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- is -O-, -CH = CH-, or. An alkyl having 5 to 20 carbon atoms may be replaced with a cycloalkylene having 1 to 40 carbon atoms, and at least one hydrogen may be replaced with a halogen, and at least one -CH _2- may be replaced with -O- or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms;
x is greater than or equal to 1;
In formula (B),
^R2 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, or alkyl having 1 to 40 carbon atoms. At least one hydrogen is replaced by a halogen or an alkyl having 1 to 20 carbon atoms in the aryl in an aryl having 6 to 20 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, and an aryl alkyl having 7 to 40 carbon atoms. Alternatively, in the alkylene in the arylalkyl having 7 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- is -O-, -CH = CH-, or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms, or in an alkyl having 1 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- may be replaced with -O- or carbon. May be replaced with the number 5-20 cycloalkylene;
y is 1 or more.

With this configuration, the density of the cage-type silsesquioxane portion is low and the dielectric constant is low, and since it is large and difficult to move molecularly, the chemically bonded polysiloxane chain is also hard to vibrate, so that the dielectric constant due to molecular vibration is low. It is possible to realize a thermosetting composition having a low dielectric constant as a whole. The higher the ratio of the cage-type silsesquioxane, the lower the dielectric constant, but the cured product becomes hard and it becomes difficult to combine it with glass cloth or the like, so it is preferable to set the ratio suitable for the application.

The composition for a low dielectric constant and high heat resistant substrate according to the second aspect of the present invention has a weight average molecular weight of the polysiloxane copolymer according to the first aspect of the present invention in the range of 2,000 to 10,000,000. be. With such a configuration, it is possible to contain a more preferable compound in that it is difficult to peel off from the substrate and has high durability.

The composition for a low dielectric constant and high heat resistant substrate according to the third aspect of the present invention has a low dielectric constant and a glass transition temperature of the polysiloxane copolymer according to the first and second aspects of the present invention is 0 ° C. or higher. It is a highly heat-resistant thermosetting composition. With such a configuration, in the temperature range in which the low-dielectric substrate is used, it is possible to contain a more preferable compound in that the fluctuation of physical properties such as elastic modulus is small and it is resistant to temperature cycles and the like.

The composition for a low dielectric constant and high heat resistant substrate according to the fourth aspect of the present invention is a polysiloxane copolymer obtained from the calculation formula represented by the formula (α) in the first to third aspects of the present invention. A thermosetting composition having a low dielectric constant and high heat resistance having a crosslink density n of 150 mol / m ³ or more.
n = E'/ 3RT ... (α)
In formula (α), n: crosslink density (mol / m ³ ), E': storage elastic modulus (Pa), R: gas constant ((Pa · m ³ ) / K · mol)), T: temperature (K). )
With such a configuration, a more preferable compound can be contained in terms of high mechanical strength.

The composition for a low dielectric constant high heat resistant substrate according to the fifth aspect of the present invention is a low dielectric constant and high heat resistant thermosetting composition further containing glass cloth as a reinforcing material in the first to fourth aspects of the present invention. Is. With this configuration, the high heat-resistant composition for a low-dielectric substrate of the present invention can be used for applications that are difficult to use with a resin alone, such as a large-area printed circuit board.

The composition for a low dielectric constant high heat resistant substrate according to the sixth aspect of the present invention has a low dielectric constant and high heat resistant thermosetting composition in which the reinforcing material is a low dielectric glass cloth in the fifth aspect of the present invention. It is a thing. With this configuration, it is possible to form an electronic circuit board with a low dielectric constant even if the glass is composited.

A seventh aspect of the present invention is an interlayer insulation for a low-dielectric substrate or a low-dielectric substrate produced by synthesizing the composition for a low-dielectric-constant high heat-resistant substrate according to the first to sixth aspects of the present invention and then curing the composition. A film or a low dielectric coating layer. When formed in this way, it is possible to form a low-dielectric and high-heat resistant substrate suitable for high-speed data communication, high-speed data processing, and manufacture of sensors and antennas having a high drive frequency.

The eighth aspect of the present invention uses a low-dielectric substrate, an interlayer insulating film for a low-dielectric substrate, and a low-dielectric coating layer comprising the composition for a low-dielectric-constant high heat-resistant substrate according to the first to sixth aspects of the present invention. The electronic circuits, sensors, antennas, radars, or electronic devices that used them. With this configuration, it is possible to configure a highly reliable electronic device that has high data transmission, few malfunctions, and does not deteriorate even at high temperatures.

The present inventors react and bond a silsesquioxane compound having a cage-type structure with high heat resistance and chemical stability and a compound containing a chain siloxane structure without using an organic bonding group such as acrylic or imide. At that time, by optimizing the ratio of the silsesquioxane compound having a cage structure and the chain siloxane structure, the dielectric constants at 1 GHz and 10 GHz are both 3.0 or less, and the weather resistance and heat resistance (weather resistance and heat resistance ( We have found a cured film having an extremely high 1% or 5% weight loss temperature (1% or 5% weight loss temperature) of 350 ° C. or higher, and a liquid composition as a raw material thereof, and completed the present invention.

It is a conceptual diagram of low dielectric constant of the material for an electronic substrate of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, the present invention is not limited to the following embodiments.

The terms used in the present invention will be described. The compound represented by the formula (1) may be referred to as a compound (1). Compounds represented by other formulas may also be abbreviated in the same manner. The expression "at least one A may be replaced by B or C" is the expression at least one A in addition to the case where at least one A is replaced by B and the case where at least one A is replaced by C. Means that at the same time that is replaced by B, at least one of the other A's may be replaced by C. In the chemical formulas described herein, Me is methyl and Ph is phenyl. In the examples, the display data of the electronic balance is shown using g (gram) which is a mass unit. Weight% and weight ratio are data based on such numerical values.

[Composition for low dielectric constant and high heat resistant substrate]
The composition for a low dielectric constant high heat resistant substrate of the present invention is composed of a polysiloxane copolymer, and is a composition capable of forming a low dielectric constant high heat resistant substrate and a low dielectric insulating layer by thermosetting or the like. FIG. 1 is a conceptual diagram of reducing the dielectric constant in the present invention. The cage-shaped silsesquioxane not only has a low dielectric constant but also has a bulky part in the polymer chain, and the cage-shaped silsesquioxane has a cage-shaped sill. The siloxane chain that binds sesquioxane also becomes difficult to move. Further, the fact that only the silicon-oxygen bond is contained in the main chain and the hydrocarbon bond group that causes the polarity is not contained not only contributes to the reduction of dielectric property but also improves the heat resistance.

<Polysiloxane copolymer>
The polysiloxane copolymer comprises a cage-type silsesquioxane repeating unit represented by the formula (A) and a chain-shaped siloxane repeating unit represented by the formula (B), and may contain other components.

Cage-type silsesquioxane repeating unit represented by the formula (A)

In formula (A), ^R0 is independently an aryl having 6 to 20 carbon atoms or a cycloalkyl having 5 to 6 carbon atoms, and in an aryl having 6 to 20 carbon atoms and a cycloalkyl having 5 to 6 carbon atoms. At least one hydrogen may be replaced with a halogen or an alkyl having 1 to 20 carbon atoms;
^R1 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, or alkyl having 1 to 40 carbon atoms. At least one hydrogen is replaced by a halogen or an alkyl having 1 to 20 carbon atoms in the aryl in an aryl having 6 to 20 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, and an aryl alkyl having 7 to 40 carbon atoms. Alternatively, in the alkylene in the arylalkyl having 7 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- is -O-, -CH = CH-, or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms, or in an alkyl having 1 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- may be replaced with -O- or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms;
x is 1 or more.

(R ⁰ in equation (A))
^R0 is independently an aryl having 6 to 20 carbon atoms or a cycloalkyl having 5 to 6 carbon atoms.
Examples of the aryl having 6 to 20 carbon atoms include phenyl, naphthyl, anthryl, phenanthryl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, perylenyl and the like. Of these, phenyl, naphthyl, anthryl, and phenanthryl are preferred, with phenyl, naphthyl and anthryl being more preferred.
Examples of the cycloalkyl having 5 to 6 carbon atoms include cyclopentyl and cyclohexyl.
^R0 is preferably phenyl or cyclohexyl.

(R ¹ in equation (A))
^R1 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl with 6 to 20 carbon atoms, cycloalkyl with 5 to 6 carbon atoms, arylalkyl with 7 to 40 carbon atoms, or alkyl with 1 to 40 carbon atoms. be.
Examples of the aryl having 6 to 20 carbon atoms and the cycloalkyl having 5 to 6 carbon atoms are the same as those described in ^R0 .
Examples of the arylalkyl having 7 to 40 carbon atoms include benzyl, phenethyl, diphenylmethyl, triphenylmethyl, 1-naphthylmethyl, 2-naphthylmethyl, 2,2-diphenylethyl, 3-phenylpropyl and 4-phenylbutyl. , 5-Phenylpentyl.
Examples of alkyl having 1 to 40 carbon atoms include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, sec-pentyl, and iso-. Examples include pentyl, tert-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, dodecyl and octadecyl.
R ¹ is preferably selected from phenyl, cyclohexyl, and alkyl having 1-5 carbon atoms, preferably phenyl or methyl.

(X in formula (A))
x is 1 or more, and the total number of cage-type silsesquioxane repeating units represented by the formula (A) contained in the polysiloxane copolymer is, for example, 1 to 500.

Chained siloxane repeating unit represented by the formula (B)

In formula (B), R ² is independently hydrogen, vinyl, allyl, hydroxyl group, aryl with 6 to 20 carbon atoms, cycloalkyl with 5 to 6 carbon atoms, arylalkyl with 7 to 40 carbon atoms, or carbon number of carbon atoms. In the aryls of 1 to 40 alkyl, 6 to 20 carbon atoms, 5 to 6 carbon atoms cycloalkyl and 7 to 40 carbon atoms arylalkyl, at least one hydrogen is halogen or 1 to 1 to carbon atoms. It may be replaced with 20 alkyl, or at least one hydrogen may be replaced with halogen in the alkylene in the arylalkyl having 7 to 40 carbon atoms, and at least one -CH _2- may be replaced with -O-,-. It may be replaced with CH = CH-, or a cycloalkylene having 5 to 20 carbon atoms, and in an alkyl having 1 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- May be replaced with —O— or a cycloalkylene with 5 to 20 carbon atoms;
y is 1 or more.

(Y in equation (B))
y represents a real number of 1 or more, and the total number of chain siloxane repeating units represented by the formula (B) contained in the polysiloxane copolymer (y1 + y2 described later) is, for example, 1 to 3000.

The polysiloxane copolymer is bonded to the surface of a substance selected from an inorganic substance and an organic substance via a chain siloxane repeating unit represented by the formula (B). Here, the bond is preferably a chemical bond. For example, a functional group such as a hydroxyl group may be imparted to the surface of the substance, and a chemical bond may be formed by a chemical reaction between the functional group and the terminal hydroxyl group of the chain siloxane repeating unit represented by the formula (B). The chain siloxane repeating unit represented by the formula (B) may be directly bonded to the surface of the substance, or may be bonded via a spacer or the like.

"The polysiloxane copolymer binds to the surface of a substance selected from an inorganic substance and an organic substance via a chain siloxane repeating unit represented by the formula (B)" is represented by the formula (B). The chain siloxane repeating unit linker portion) first binds to the surface of the substance, and then the cage-type silsesquioxane repeating unit represented by the formula (A) and the chain siloxane repeating unit represented by the formula (B) are repeated. It means that the units are combined in any proportion and in any order.
[Substances selected from inorganic and organic substances] _{-By 1- (} A _x By 2)
The number of repetitions y1 in the chain-like siloxane repeating unit (linker portion) represented by the formula (B) bonded to the surface of the substance is, for example, 1 to 1000.
In (A _x By 2), the number x of the cage-type _{silsesquioxane} repeating units represented by the continuous formula (A) is, for example, 1 to 5, and the chain shape represented by the continuous formula (B). The siloxane repeating unit y2 is, for example, 1 to 30.

式（Ｃ）中、Ｒ^４は独立して、水素、水酸基、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、炭素数７～４０のアリールアルキル、炭素数１～４０のアルキル、炭素数１～４０のアルコキシ、ビニル、またはアリルであり、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、および前記炭素数７～４０のアリールアルキル中のアリールにおいて、少なくとも１つの水素がハロゲンまたは炭素数１～２０のアルキルで置き換えられてもよく、炭素数７～４０のアリールアルキル中のアルキレンにおいて、少なくとも１つの水素がハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が、－Ｏ－、－ＣＨ＝ＣＨ－、または炭素数５～２０のシクロアルキレンで置き換えられてもよく、炭素数１～４０のアルキルにおいて、少なくとも１つの水素が、ハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が、－Ｏ－または炭素数５～２０のシクロアルキレンで置き換えられてもよく、炭素数１～４０のアルコキシにおいて、少なくとも１つの水素が独立してハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が、－Ｏ－または炭素数５～２０のシクロアルキレンで置き換えられてもよい。 In the present invention, the terminal different from the terminal bonded to the substance selected from the inorganic substance and the organic substance of the polysiloxane copolymer is not particularly limited and may be a hydroxyl group, but the group of the following formula (C) may be used. You may have.

In formula (C), ^R4 is independently hydrogen, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, and alkyl having 1 to 40 carbon atoms. , An alkoxy, vinyl, or allyl having 1 to 40 carbon atoms, and at least 1 in the aryl having 6 to 20 carbon atoms, the cycloalkyl having 5 to 6 carbon atoms, and the aryl alkyl having 7 to 40 carbon atoms. One hydrogen may be replaced with a halogen or an alkyl having 1 to 20 carbon atoms, and at least one hydrogen may be replaced with a halogen in the alkylene in the arylalkyl having 7 to 40 carbon atoms, and at least one -CH. _2- may be replaced with -O-, -CH = CH-, or a cycloalkylene having 5 to 20 carbon atoms, in which at least one hydrogen is replaced with a halogen in an alkyl having 1 to 40 carbon atoms. Also, at least one -CH _2- may be replaced with -O- or a cycloalkylene having 5 to 20 carbon atoms, and in an alkoxy having 1 to 40 carbon atoms, at least one hydrogen is independently halogen. It may be replaced, and at least one -CH _2- may be replaced with -O- or a cycloalkylene having 5 to 20 carbon atoms.

Examples of the aryl having 6 to 20 carbon atoms and the cycloalkyl having 5 to 6 carbon atoms are the same as those described in ^R0 .
Examples of the arylalkyl having 7 to 40 carbon atoms and the alkyl having 1 to 40 carbon atoms are the same as those described in ^R1 .
The alkoxy having 1 to 40 carbon atoms is not particularly limited, but is preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, and propoxy.
^R4 is preferably hydrogen, methylphenyl, vinyl, allyl, or a hydroxyl group.

In the polysiloxane copolymer contained in the composition for a low dielectric constant and high heat resistant substrate of the present invention, the molar ratio of the repeating unit represented by the formula (A) to the chain siloxane repeating unit represented by the formula (B). (X: y) is 1: 1 to 1:10.
In the polysiloxane copolymer of the present invention, the mass% occupied by the chain siloxane repeating unit represented by the formulas (A) and (B) is usually 10% or more, preferably 30% or more, more preferably. Is 50% or more, particularly preferably 70% or more, usually less than 100%, preferably 99% or less. That is, a unit other than the repeating unit represented by the formula (1) may be included as long as the effect of the present invention is not significantly impaired. Examples of such a unit include-(CH ₂ -CH ₂ )-,-(CH = CH)-,-(O-SiMe ₂ -C ₆ H ₄ -SiMe ₂ )-.

The weight average molecular weight (Mw) of the polysiloxane copolymer in the present invention is not particularly limited, but is preferably 2,000 or more, more preferably 10,000 or more, and preferably 1,000,000 or less, more preferably. Is 500,000 or less, more preferably 200,000 or less. The weight average molecular weight is determined by calculating a chromatogram obtained by gel permeation chromatography (GPC) from a calibration curve obtained with a molecular weight standard sample, as described in Examples described later.
The polydispersity is, for example, 1 to 4.

These polysiloxane copolymers can be produced, for example, by the following steps.
(I) Equilibrium polymerization of chain or cyclic siloxane on the surface of a substance selected from inorganic and organic substances, followed by
(Ii) Step of equilibrium polymerization of cage-type silsesquioxane

For example, a chain siloxane is grafted on the silica surface by reacting an inorganic oxide (silica) whose surface is a hydroxyl group with a chain or cyclic siloxane, an acid catalyst, or a solvent. Next, by adding terminal silanol-type cage-type silsesquioxane to the solution being polymerized, equilibrium polymerization with the grafted siloxane polymer is carried out, and cage-type silsesquioxane is incorporated in the middle of the chain siloxane, and the molecular necklace. Polymer-grafted silica is obtained.

Examples of the chain or cyclic siloxane include compounds represented by the formula (b) or the formula (c). Either or both of these can be used. It is preferable that a reactive functional group such as a hydroxyl group is present on the surface of a substance selected from an inorganic substance and an organic substance, and a surface treatment may be performed to introduce such a reactive functional group.

R ^{2 in the formula (b) and the formula (c) is a group defined in the same manner as R 2 in} the formula (B), and so is the preferred example. n is an integer of 2 to 30.

Examples of the compound represented by the formula (b) include 2,2,4,4,6,6-hexamethylcyclotrisiloxane and 2,4,6-triethyl-2,4,6-trimethylcyclotrisiloxane. , 2,2,4,4,6,6-hexaethylcyclotrisiloxane, 2,4,6-trimethyl-2,4,6-tripropylcyclotrisiloxane, 2,4,6-triethyl-2,4 , 6-Tripropylcyclotrisiloxane, 2,2,4,4,6,6-hexapropylcyclotrisiloxane, 2,4,6-trimethyl-2,4,6-tris (1-methylethyl) cyclotri Siloxane, 2,4,6-triethyl-2,4,6-tris (1-methylethyl) cyclotrisiloxane 2,2,4,4,6,6-hexakis (1-methylethyl) cyclotrisiloxane, 2, , 4,6-Tributyl-2,4,6-trimethylcyclotrisiloxane, 2,4,6-tributyl-2,4,6-triethylcyclotrisiloxane, 2,2,4,4,6,6-hexa Butylcyclotrisiloxane, 2,4,6-trimethyl-2,4,6-tris (1,1-dimethylethyl) cyclotrisiloxane, 2,46-triethyl-2,4,6-tris (1,1-tris) Dimethylethyl) cyclotrisiloxane, 2,4,6-tris (1,1-dimethylethyl) -2,4,6-tripropylcyclotrisiloxane, 2,2,4,4,66-hexakis (1,1) -Dimethylethyl) cyclotrisiloxane, 2,4,6-trimethyl-2,4,6-tris (trifluoromethyl) cyclotrisiloxane, 2,2,4,4,6,6-hexakis (trifluoromethyl) Cyclotrisiloxane, 2,2,4,4,6,6-hexakis (1,1,2,2,2-pentafluoroethyl) cyclotrisiloxane, 2,4,6-trimethyl-2,4,6- Tris (3,3,3-trifluoropropyl) cyclotrisiloxane, 2,2,4,4,6,6-hexakis (3,3,3-trifluoropropyl) cyclotrisiloxane, 2,4,6- Trimethyl-2,4,6-triphenylcyclotrisiloxane, 2,2,4,4,6,6-hexaphenylcyclotrisiloxane, 2,4,6-tricyclohexyl-2,4,6-trimethylcyclo Trisiloxane, 2,2,4,4,6,6-hexacyclohexylcyclotrisiloxane, 2,2,4,4,6,6-hexavinylcyclotrisiloxane, 2 , 4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 2,2,4,4,6,6,8,8-octamethylcyclotetrasiloxane, 2,4,6,8-tetraethyl -2,4,6,8-Tetramethylcyclotetrasiloxane, 2,2,4,4,6,6,8,8-octaethylcyclotrisiloxane, 2,4,6,8-tetramethyl-2, 4,6,8-Tetrapropylcyclotetrasiloxane, 2,4,6,8-tetraethyl-2,4,6,8-tetrapropylcyclotetrasiloxane, 2,2,4,4,6,6,8, 8-octapropylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis (1-methylethyl) cyclotetrasiloxane, 2,4,6,8-tetraethyl-2, 4,6,8-Tetraxane (1-methylethyl) cyclotetrasiloxane 2,2,4,4,6,6,8,8-octakis (1-methylethyl) cyclotetrasiloxane, 2,4,6,8 -Tetrabutyl-2,4,6,8-Tetramethylcyclotetrasiloxane, 2,4,6,8-Tetrabutyl-2,4,6,8-Tetraethylcyclotetrasiloxane, 2,2,4,4,6 6,8,8-Octabutylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis (1,1-dimethylethyl) cyclotetrasiloxane, 2,4,6 8-Tetraethyl-2,4,6,8-tetrakis (1,1-dimethylethyl) cyclotetrasiloxane, 2,4,6,8-tetrakis (1,1-dimethylethyl) -2,4,6,8 -Tetrapropylcyclotetrasiloxane, 2,2,4,4,6,6,8,8-octakis (1,1-dimethylethyl) cyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4 , 6,8-Tetrakiss (trifluoromethyl) cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octakis (trifluoromethyl) cyclotetrasiloxane, 2,2,4,4,6 , 6,8,8-octakis (1,1,2,2,2-pentafluoroethyl) cyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis (3, 3,3-Trifluoropropyl) cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octakis (3,3,3-trifluoropropyl) cyclotetrasiloxane, 2,4,6 8-Tetramethyl-2, 4,6,8-Tetraphenylcyclotetrasiloxane, 2,2,4,4,6,6,8,8-octaphenylcyclotetrasiloxane, 2,4,6,8-tetracyclohexyl-2,4 6,8-Tetramethylcyclotetrasiloxane, 2,2,4,4,6,6,8,8-octacyclohexylcyclotetrasiloxane, 2,2,4,4,6,6,8-octa Vinylcyclotetrasiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 2,6-dietinyl-2,4,4,6,8,8-hexamethyl Cyclotetrasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethylcyclopentasiloxane, 2,4,6,8,10-pentaethyl-2,4,6,8, 10-Pentamethylcyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decaethylcyclotrisiloxane, 2,4,6,8.10-pentamethyl-2,4 6,8-Pentapropylcyclopentasiloxane, 2,4,6,8,10-pentaethyl-2,4,6,8,10-pentapropylcyclopentasiloxane, 2,2,4,4,6,6 8,8,10,10-decapropylcyclopentasiloxane, 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentakis (1-methylethyl) cyclopentasiloxane, 2,4 , 6,8,10-Pentaethyl-2,4,6,8,10-pentakis (1-methylethyl) cyclopentasiloxane 2,2,4,4,6,6,8,8,10,10-decakis (1-Methylethyl) Cyclopentasiloxane, 2,4,6,8,10-Pentabutyl-2,4,6,8,10-Pentamethylcyclopentasiloxane, 2,4,6,8,10-Pentabutyl- 2,4,6,8,10-pentaethylcyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decabutylcyclopentasiloxane, 2,4,6,8, 10,10-Pentamethyl-2,4,6,8,10,10-pentakis (1,1-dimethylethyl) cyclopentasiloxane, 2,4,6,8,10-pentaethyl-2,4,6,8 , 10-Pentakis (1,1-dimethylethyl) cyclopentasiloxane, 2,4,6,8,10-pentakis (1,1-dimethylethyl) -2,4,6,8,10-pentapropylcyclopenta Siloxane, 2,2,4,4,6 , 6,8,8,10,10-decakis (1,1-dimethylethyl) cyclopentasiloxane, 2,4,6,8,10-pentamethyl-2,4,6,8-pentakis (trifluoromethyl) Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10.10-decakis (trifluoromethyl) cyclopentasiloxane, 2,2,4,4,6,6,8,8, 10,10-decakis (1,1,2,2,2-pentafluoroethyl) cyclopentasiloxane, 2,4,6,8,10,10-pentamethyl-2,4,6,8-pentakis (3, 3,3-Trifluoropropyl) cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decakis (3,3,3-trifluoropropyl) cyclopentasiloxane, 2, 4,6,8,10-Pentamethyl-2,4,6,8-pentaphenylcyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decaphenylcyclopentasiloxane, 2,4,6,8,10-pentacyclohexyl-2,4,6,8,10-pentamethylcyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10- Decacyclohexylcyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decavinylcyclopentasiloxane, 2,4,6,8,10-pentamethyl-2,4,6 , 8,10-Pentavinylcyclopentasiloxane, among which low molecular weight cyclic siloxanes in which ^R2 is an alkyl having 1 to 40 carbon atoms are preferable, hexamethylcyclotrisiloxane (D3) and octamethylcyclotetrasiloxane (D3). Cyclic siloxanes such as D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) are more preferred, and octamethylcyclotetrasiloxane is particularly preferred from the standpoint of availability, cost, and handling.

Examples of the compound represented by the formula (c) include, for example.
1,1,3,3-Tetramethyl-1,3-disiloxanediol, 1,1,3,3,5,5-hexamethyl-1,5-trisiloxanediol, 1,1,3,3,5 , 5,7,7-Octamethyl-1,7-tetrasiloxanediol, 1,1,3,3,5,5,7,7,9,9-decamethyl-1,9-pentasiloxanediol, 1,1 , 3,3-Tetraphenyl-1,3-disiloxanediol, 1,1,3,3,5,5-hexaphenyl-1,5-trisiloxanediol, DMS-S12 (trade name, manufactured by Gelest), DMS-S14 (trade name, manufactured by Gelest), DMS-S15 (trade name, manufactured by Gelest)
1,1,1,3,3,3-hexamethyldisiloxane, 1,1,1,3,3,5,5,5-octamethyltrisiloxane, 1,1,1,3,3,5 5,7,7-Decamethyltetrasiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3-diallyl-1,1,3,3-tetramethyldisiloxane, 1 , 5-Divinyl-1,1,3,3,5,5-heptamethyltrisiloxane, 1,5-diallyl-1,1,3,3,5,5-heptamethyltrisiloxane, DMS-V00 (Product name, manufactured by Gelest), DMS-V03 (Product name, manufactured by Gelest), DMS-V05 (Product name, manufactured by Gelest)
1,1,3,3-tetramethyldisiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane, 1,1,3,3,5,5,7,7-octamethyltetrasiloxane 1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11- Dodecamethylhexasiloxane, 1,3-dimethyl-1,3-diphenyldisiloxane, 1,1,3,3-tetraphenyldisiloxane, 1,3-cyclohexyl-1,3-dimethyldisiloxane, 1,1, 1,3,3-Tetracyclohexamethyldisiloxane, 1,3-diethyl-1,3-dimethyldisiloxane, 1,1,3,3-tetraethyldisiloxane, 1,3-dimethyl-1,3-dipropyl Disiloxane, 1,3-diethyl-1,3-dipropyldisiloxane, 1,1,3,3-tetrapropyldisiloxane, 1,3-dimethyl-1,3-bis (1-methylethyl) disiloxane 1,1,3-diethyl-1,3-bis (1-methylethyl) disiloxane, 1,1,3,3-tetrakis (1-methylethyl) disiloxane, 1,1,3,3-tetrakis (1) , 1-dimethylethyl) disiloxane, 1,3-bis (1,1-dimethylethyl) -1,3-dimethyldisiloxane, DMS-Hm15 (trade name, manufactured by Gelest), DMS-Hm25 (trade name, Gelest) , DMS-H03 (trade name, manufactured by Gelest), DMS-H11 (trade name, manufactured by Gelest), FM 1105 (trade name, manufactured by JNC Co., Ltd.), FM 1111 (trade name, manufactured by JNC Co., Ltd.) , 1,3-Difluoro-1,1,3,3-tetramethyldisiloxane, 1,5-difluoro-1,1,3,3,5,5-hexamethyldisiloxane, 1,1,3,3 -Tetramethyl-1,3-bis (trifluoromethyl) disiloxane, 1,1,3,3,5,5-hexamethyl-1,5-bis (trifluoromethyl) disiloxane, 1,3-dimethoxy- 1,1,3,3-Tetramethyldisiloxane, 1,5-dimethoxy-1,1,1,3,3,5,5-hexamethyltrisiloxane, 1,3-diethoxy-1,1,3,3- Tetramethyldisiloxane, 1,5-diethoxy-1,1,1,3,3,5,5-hexamethyltrisiloxane, 1,1,3,3-tetramethyl-1,3-dipropoxydisiloxane 1,1, 1,3,3,5,5-hexamethyl-1,5-di Propoxytrisiloxane 1,1,3,5,7,7-hexamethoxy-1,3,5,7-tetramethyltetrasiloxane, 3,3,11,11-tetramethoxy-6,6,8,8 -Tetramethyl-2,7,12-Trioxa-3,6,8,11-Tetrasilatridecan, 4,4,12,12-Tetraethoxy-7,7,9,9-Tetramethyl-3,8, 13-Trioxa-4,7,9,12-Tetrasilapentadecane, 1,3-dietinyl-1,1,1,3,3-tetramethyldisiloxane, 1,5-dietinyl l-1,1,3,3, 5,5-Hexamethyltrisiloxane, FM 2205 (trade name, manufactured by JNC Co., Ltd.), 1,1,3,3-tetramethyl-1,3-di-2-propane-1-yldisiloxane, 1, 1,3,3,5,5-hexamethyl-1,5-di-2-propane-1-yltrisiloxane, FM-4411 (trade name, manufactured by JNC Co., Ltd.), FM-4421 (trade name, JNC) (Product name, manufactured by JNC Co., Ltd.), FM-4425 (trade name, manufactured by JNC Co., Ltd.), DMS-C15 (trade name, manufactured by Gelest), DMS-C16 (trade name, manufactured by Gelest), DMS-C21 (trade name, manufactured by Gelest). ), DMS-CA21 (trade name, manufactured by Gelest).

式（ａ）におけるＲ^０は、式（Ａ）におけるＲ^０と同様に定義される基であり、好ましい例も同様である。
式（ａ）におけるＲ^１は、式（Ａ）におけるＲ^１と同様に定義される基であり、好ましい例も同様である。
式（ａ）で表される化合物は、例えば、特開２００６－０２２２０７号公報の記載を参照して合成することができ、以下に示される化合物が好ましい。この化合物において、Ｐｈはフェニルを示し、Ｃ－Ｈｅｘはシクロヘキシルを示す。 Examples of the cage-type silsesquioxane include compounds represented by the formula (a).

R ^{0 in the formula (a) is a group defined in the same manner as R 0 in} the formula (A), and so is a preferable example.
R ^{1 in the formula (a) is a group defined in the same manner as R 1 in} the formula (A), and so is a preferable example.
The compound represented by the formula (a) can be synthesized, for example, with reference to the description in JP-A-2006-022207, and the compounds shown below are preferable. In this compound, Ph represents phenyl and C-Hex represents cyclohexyl.

Further, in the polysiloxane copolymer obtained in the above step (ii), a compound represented by the formula (d) is added to a terminal different from the end bonded to the surface of a substance selected from the inorganic substance and the organic substance of the polysiloxane. By reacting, a terminal different from the end bonded to the surface of the substance of the polysiloxane copolymer may be modified.

式（ｄ）中、Ｒ^３は、式（Ｃ）におけるＲ^２で説明したとおりであり、好ましい基も同様である。
Ｒ^４は独立して、水素、ビニル、アリル、水酸基、炭素数６～２０のアリール、炭素数５～６のシクロアルキル、炭素数７～４０のアリールアルキル、または炭素数１～４０のアルキルであり、炭素数６～２０のアリール、前記炭素数５～６のシクロアルキルおよび前記炭素数７～４０のアリールアルキル中のアリールは、少なくとも１つの水素が独立してハロゲンまたは炭素数１～２０のアルキルで置き換えられてもよく、前記炭素数７～４０のアリールアルキル中のアルキレンは、少なくとも１つの水素がハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が独立して－Ｏ－、－ＣＨ＝ＣＨ－、または炭素数５～２０のシクロアルキレンで置き換えられてもよく、前記炭素数１～４０のアルキルは、少なくとも１つの水素が独立してハロゲンで置き換えられてもよく、少なくとも１つの－ＣＨ_２－が独立して－Ｏ－または炭素数５～２０のシクロアルキレンで置き換えられてもよい。
ｎは１～３０の整数である。
式（ｄ）で表される化合物としては、例えば、ヘキサメチルジシロキサン、オクタメチルトリシロキサン、デカメチルテトラシロキサン、ヘキサフェニルジシロキサン、オクタフェニルトリシロキサン、デカフェニルテトラシロキサン、Ｇｅｌｅｓｔ製 ＤＭＡ－Ｔ０７Ｒが挙げられる。 <Compound represented by the formula (d)>

In formula (d), R ³ is as described in R ² in formula (C), and so is the preferred group.
^R4 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl with 6 to 20 carbon atoms, cycloalkyl with 5 to 6 carbon atoms, arylalkyl with 7 to 40 carbon atoms, or alkyl with 1 to 40 carbon atoms. The aryl in the aryl having 6 to 20 carbon atoms, the cycloalkyl having 5 to 6 carbon atoms, and the arylalkyl having 7 to 40 carbon atoms has at least one hydrogen independently halogen or 1 to 20 carbon atoms. The alkylene in the arylalkyl having 7 to 40 carbon atoms may be replaced with an alkyl, and at least one hydrogen may be replaced with a halogen, and at least one -CH ₂ --is independently -O-,. -CH = CH-, or a cycloalkylene having 5 to 20 carbon atoms may be substituted, and the alkyl having 1 to 40 carbon atoms may have at least one hydrogen independently replaced with a halogen, and at least one. Two -CH _2- may be independently replaced with -O- or a cycloalkylene having 5 to 20 carbon atoms.
n is an integer from 1 to 30.
Examples of the compound represented by the formula (d) include hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexaphenyldisiloxane, octaphenyltrisiloxane, decaphenyltetrasiloxane, and Gelest's DMA-T07R. Can be mentioned.

Equilibrium polymerization can be adopted in the above steps (i) and (ii).
The equilibrium polymerization can be carried out, for example, with reference to the method described in JP-A-2017-014320. It is preferable to use the following solvent and acid catalyst for the reaction. Further, it is preferable to carry out the reaction in an inert atmosphere such as nitrogen (N ₂ ). Further, it is preferable to carry out the reaction while stirring. The reaction temperature is, for example, 25 to 120 ° C.

<Solvent>
The solvent used in the reaction is not particularly limited as long as it can dissolve the raw material compounds (a), (b) and / or (c). Preferred solvents are hydrocarbon solvents such as butane, hexane, heptane, octane, cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylen, anisole; diethyl ether, diisopropyl ether, 1,2-dimethoxyethane. , Ether solvent such as tetrahydrofuran (THF), dioxane, halogenated hydrocarbon solvent such as methylene chloride, carbon tetrachloride; ester solvent such as ethyl acetate; glycol ester solvent such as propylene glycol monomethyl ether acetate (PGMEA). Nitrogen-containing solvents such as dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), pyridine; alcohol solvents such as methanol, ethanol, isopropanol, butanol; acetone, It is a ketone solvent such as methyl ethyl ketone. Toluene, mesitylene, anisole, tetrahydrofuran, cyclopentyl methyl ether, propylene glycol monomethyl ether acetate and 2- (2-ethoxyethoxy) ethyl acetate are preferable, and toluene and propylene glycol monomethyl ether acetate (PGMEA) are more preferable. One type of solvent may be used, or two or more types may be used. Further, the solvent may be dehydrated before use. The amount of the solvent used is not particularly limited, but is usually 10% by mass or more, preferably 20% by mass or more, and usually 1000% by mass or less, preferably 500% by mass or less, based on the raw material compound. ..

<Catalyst>
It is preferable to use an acid catalyst for the equilibrium polymerization.
Acid catalysts include, for example, phosphoric acid, toluenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, sulfuric acid, nitric acid, acetic acid and benzoic acid, DIAION ™ RCP-160M (strongly acidic ion exchange). Resin, manufactured by Mitsubishi Chemical Co., Ltd.) can be mentioned.
The amount of the catalyst added is usually 0.001% by mass or more, preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and usually 10% by mass or less, based on the polysiloxane copolymer. It is preferably 5% by mass or less, more preferably 3% by mass or less. When two or more kinds of catalysts are used, it is preferable that the total content is within the above range.

<Glass cloth>
As the glass cloth, it is preferable to use a glass cloth having the structure used for the electronic circuit board. Even when combined with a resin, the smoothness and homogeneity required for an electric circuit board, the thickness after curing, the drilling characteristics of a drill, and the cross-sectional structure after cutting the substrate have been established. More preferably, a glass cloth using low-dielectric glass is preferable instead of ordinary glass. Not only the dielectric constant of the entire composite material is lowered, but also the difference in the dielectric constant between the glass and the polysiloxane copolymer is small, which is preferable in terms of the equivalent circuit. Further, when adjusting the coefficient of thermal expansion in order to improve the thermal cycle characteristics after the copper foil is bonded, a glass cloth for adjusting the coefficient of thermal expansion can be used. Keeping the coefficient of thermal expansion close to that of the copper foil for circuits reduces thermal strain during temperature changes and improves long-term reliability.

<Additives>
As an additive, a dispersant / defoaming agent / coloring pigment / silane coupling agent, an adhesion improver, a leveling agent, and a thixo property adjusting agent may be further added to the composition for a low dielectric constant and high heat resistant substrate.
By adding 0.1 to 35 parts by weight of the adhesiveness improving agent to 100 parts by weight of the glass cloth, peeling of the glass fiber and the polysiloxane polymer is prevented, and the mechanical strength and the drill resistance are improved. Can be done.
The defoaming agents are silicone-based defoaming agents, modified silicone-based defoaming agents, silica-based defoaming agents, waxes, polysiloxanes, polyether-modified polydimethylsiloxanes, defoaming polymers, paraffin oils, and defoaming fatty groups. Defoamers and the like can be mentioned. By adding 0.1 to 5 parts by weight with respect to 100 parts by weight of the composition, defoaming property is exhibited and the workability of glass cloth impregnation is improved.
The silane coupling agent not only enhances the affinity between the glass cloth and the polysiloxane copolymer, but can also be expected to have the effect of improving the adhesion to the underlying substrate and the copper foil for the circuit. A circuit of a copper foil formed on a base substrate by adding 0.1 to 5 parts by weight to 100 parts by weight of the composition, a copper foil bonded on the composition, and a polysiloxane copolymer. Affinity can be improved, and delamination of the base material and copper can be prevented.

<Unbound polymer compound>
The composition for a low dielectric constant and high heat resistant substrate may contain a polymer compound that adjusts the properties of the cured product as a constituent element. For example, the dielectric constant can be further reduced by adding olefinic hollow beads. As such a polymer compound, a compound that does not reduce the film-forming property and the mechanical strength is preferable. The polymer compound may be any polymer compound that does not react with the surface treatment agent and the siloxane complex or the cross-linking agent. , Polyvinyl resin, silicone resin, wax and the like.

<Solvent>
The composition for a low dielectric constant and high heat resistant substrate may contain a solvent. A dilute solvent can be added when it becomes necessary to reduce the viscosity when impregnating the glass cloth or when laminating a multilayer substrate. When the component to be polymerized is contained in the composition, the polymerization may be carried out in a solvent or in the absence of a solvent.
Preferred solvents include, for example, benzene, toluene, xylene, mesitylene, hexane, heptane, octane, nonane, decane, tetrahydrofuran, γ-butyrolactone, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, cyclohexane, methylcyclohexane, cyclopentanone. , Cyclohexanone, PGMEA and the like. The above solvent may be used alone or in combination of two or more.
It is not so meaningful to limit the ratio of the solvent used at the time of polymerization, and it may be determined for each individual case in consideration of polymerization efficiency, solvent cost, energy cost and the like.

<Others>
Stabilizers may be added to the composition for a low dielectric constant and high heat resistant substrate for ease of handling. As such stabilizers, known stabilizers can be used without limitation, and examples thereof include hydroquinone, 4-ethoxyphenol and 3,5-di-t-butyl-4-hydroxytoluene (BHT).
Further, an additive (oxide or the like) may be added to adjust the viscosity and color of the composition for a low dielectric constant and high heat resistant substrate. For example, titanium oxide for whitening, carbon black for blackening, and fine powder of silica for adjusting the viscosity can be mentioned. In addition, additives may be added to further increase the mechanical strength. For example, organic fibers and non-woven fabrics such as cellulose nanofibers, inorganic fibers and cloths such as carbon nanotubes, and fibers or long molecules such as polyvinylformal, polyvinylbutyral, polyester, polyamide, and polyimide can be mentioned as polymer additives. ..

<Manufacturing method>
Hereinafter, a method for producing a composition for a low dielectric constant and high heat resistant substrate, and a method for producing a low dielectric constant and high heat resistant substrate and a low dielectric constant and high heat resistant insulating layer from the composition will be specifically described.

To prepare a composition for a low dielectric constant and high heat resistant substrate, a necessary diluting solvent and additives are added to the solution of the polysiloxane copolymer, and the mixture is stirred and defoamed using a stirrer to the extent that the composition unevenness disappears. For example, using a rotation / revolution mixer, stirring is performed at a rotation speed of 2000 rpm for 10 minutes, and then defoaming is performed at a rotation speed of 2200 rpm for 10 minutes. In addition to the rotation / revolution mixer, it can be dispersed by using a stirring motor, a raft machine, a three-roll, a ball mill, a rotation / revolution mill, a planetary mill, a bead mill, a jet mill, or the like.

As a coating method, it is preferable to use a wet coating method in order to uniformly coat the composition for a low dielectric constant and high heat resistant substrate. Of the wet coating methods, the spin coating method, which enables simple and homogeneous film formation when producing a small amount, is preferable. When productivity is important, gravure coat method, die coat method, bar coat method, reverse coat method, roll coat method, slit coat method, dipping method, spray coat method, kiss coat method, reverse kiss coat method, air knife coat A method, a curtain coating method, an inkjet method, a flexo printing method, a screen printing method, a rod coating method and the like are preferable. The wet coating method can be appropriately selected from these methods according to the required film thickness, viscosity, curing conditions and the like.

The conditions for pre-curing the composition for a low dielectric constant and high heat-resistant substrate by thermal polymerization are a curing temperature in the range of room temperature to 350 ° C., preferably room temperature to 250 ° C., and more preferably 120 ° C. to 220 ° C. The curing time is in the range of 5 seconds to 10 hours, preferably 1 minute to 8 hours, and more preferably 5 minutes to 5 hours. After the polymerization, it is preferable to slowly cool the mixture in order to suppress stress-strain and the like. Further, the strain may be relaxed by performing a reheat treatment.

The composition for a low dielectric constant and high heat resistant substrate is used in the form of a sheet, a glass cloth composite sheet, a film, a thin film, a molded body and the like. Preferred shapes are sheets, films and thin films. The film thickness of the sheet in the present specification is 1 mm or more, the film thickness is 3 μm or more, preferably 5 to 999 μm, more preferably 20 to 300 μm, and the film thickness of the thin film is less than 3 μm. The film thickness may be appropriately changed according to the intended use. The composition for a low dielectric constant and high heat resistant substrate can be used as it is as an adhesive or a filler.

Although the present invention has been described above as being formed by controlling the composition of the polysiloxane copolymer to obtain a material for an electronic substrate having a low dielectric constant and high heat resistance, the present invention is not limited to this.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the contents described in the following examples.

The materials constituting the composition for a low dielectric constant and high heat resistant substrate used in the examples of the present invention are as follows.

<Polysiloxane copolymer>
[Synthesis Example 1]
Preparation of Silicon Compound 1 A cooling tube, a magnetic stirrer, and a thermometer protection tube were attached to a 100 mL flask, and the inside of the flask was replaced with nitrogen. In the formula (A), the compound in which R ⁰ is phenyl and R ¹ is methyl 10.0 g, octamethylcyclotetrasiloxane (D4) 2.3 g, methanesulfonic acid 0.47 g, dehydrated toluene 10.2 g, 4-methyl 2.6 g of tetrahydropyran was placed in a flask. After stirring at 80 ° C. for 7 hours, 30.0 g of water and 56.3 g of ethyl acetate were added, and the aqueous layer was extracted. After washing the organic layer with brine three times, 5.0 g of sodium sulfate and 4.2 g of Kyoward 500 were added, and the mixture was stirred overnight. The solid was filtered off by vacuum filtration and the filtrate was concentrated. Heptane and methanol were added to the concentrate, and the obtained precipitate was dried under reduced pressure at 80 ° C. to obtain 9.9 g of a white solid. The white solid obtained by ¹ H-NMR and GPC analysis is a silicon compound represented by the formula (1'), and the white solid obtained by ¹ H-NMR and GPC analysis is represented by the formula (1'). It is a silicon compound represented by a polymer in which each structural unit (silsesquioxane unit and dimethylsiloxane unit) in the formula (1') is alternately bonded, and the number n of DMS units is 2.7 on average. It turned out that there was. From GPC analysis, the number average molecular weight of silicon compound 1 was Mn = 45,300, and the weight average molecular weight was Mw = 110,000.
The number of DMS units n is such that the molar ratio of the repeating unit of the cage-type silsesquioxane (A) to the repeating unit of the chain siloxane (B) is 1: n.

The measurement conditions for GPC measurement are shown below.
<Measurement conditions>
Column: Shodex KF-804L 300 x 8.0 mm
Chromatography KF-805L 300 × 8.0mm 2 series Mobile phase: THF
Flow velocity: 1.0 ml / min
Temperature: 40 ° C
Detector: RI
Molecular Weight Standard Sample: PMMA with Known Molecular Weight

[Synthesis Example 2]
Silicon compound 2 was synthesized so that the number n of DMS (-SiMe _2- ) units in Synthesis Example 1 was 4.0 on average.

[Synthesis Example 3]
Preparation of Silicon Compound 3 Silicon compound 3 was synthesized so that the number n of DMS units in Synthesis Example 1 was 1.2 on average.

[Synthesis Example 4]
Preparation of Silicon Compound 4 Silicon compound 4 was synthesized so that the number n of DMS units in Synthesis Example 1 was 6.7 on average.

[Synthesis Example 5]
Preparation of Silicon Compound 5 In Synthesis Example 2, all the polysiloxane chains were synthesized from DMS, and a part of them synthesized a compound of HMS (-SiHMe-) (silicon compound 5). The average number of DMS units n was 3.2, and the average number of HMS units n was 0.8 so that the total number of DMS and HMS units was 4, which was the same as that of silicon compound 2.

[Example 1]
<Preparation of composition for low dielectric constant and high heat resistant substrate>
An example of preparation of a composition for a low dielectric constant and high heat resistant substrate is shown below.
To 5 g of <silicon compound 1>, 5 mL of NMP was added, and the mixture was stirred overnight. Then, this liquid was degassed twice for 3 minutes by Vacuum Foaming Rentaro (manufactured by Shinky Co., Ltd.).

-The mixed solution was applied to a non-alkali glass plate (Gorilla glass manufactured by Corning: 100 mm × 100 mm × 0.6 mm) using an applicator. The gap was adjusted so that the film thickness after drying was about 30 μm, being careful not to allow the applicator and the glass substrate to come into contact with each other (Example 1). The coated glass substrate was pre-baked on a hot plate at 110 ° C. for 30 minutes, and then fired in a clean oven at 220 ° C. for 4 hours. The cured film was peeled off from the substrate and evaluated as a low-dielectric sheet.

<Evaluation method of permittivity>
The sheet prepared by curing the silicon compound 1 was cut into strips having a width of 1.5 mm using a cutter knife. This strip was connected to a Keysight vector network analyzer, and a cavity resonator (for 1 GHz: CP431, for 10 GHz: CP531) manufactured by Kanto Electronics Applied Development Co., Ltd. was used to measure the amount of shift and attenuation of the resonance frequency. Then, the dielectric constant was calculated using the company's software.

<Heat resistance evaluation>
-Thermogravimetric (TG) measurement The 5% weight loss temperature of the composition for a low dielectric constant and high heat resistant substrate is 140 ° C to 900 ° C using a thermogravimetric / differential thermal measuring device (TG-8121 manufactured by Rigaku Co., Ltd.). It was calculated from the temperature when the amount of decrease to 5% by weight was reduced to 100% by weight. The 5% weight loss temperature was about 550 ° C.
Furthermore, the yellowing resistance of the cured film was confirmed as an index of heat resistance. Leave it in an electric oven set at 240 ° C for 4 hours, "not yellowed" is ◎, "slightly yellowed" is 〇, "deeply yellowed" is △, "brown""Things that have been burnt" to "Things that have been burnt and peeled off" are marked as x.

<Example 2>
A sample was prepared in the same manner as in Example 1 except that the silicon compound 1 was changed to the silicon compound 2, and the dielectric constant and heat resistance were evaluated.

<Example 3>
A sample was prepared in the same manner as in Example 1 except that the silicon compound 1 was changed to the silicon compound 3, and the dielectric constant and heat resistance were evaluated.

<Example 4>
A sample was prepared in the same manner as in Example 1 except that the silicon compound 1 was changed to the silicon compound 4, and the dielectric constant and heat resistance were evaluated.

<Example 5>
A sample was prepared in the same manner as in Example 1 except that the silicon compound 1 was changed to the silicon compound 5, and the dielectric constant and heat resistance were evaluated.

<Comparative Example 1>
Commercially available Kapton 500H was cut into strips having a width of 1.5 mm, and the dielectric constant and heat resistance were evaluated in the same manner as in Example 1.

Table 1 shows the evaluation of dielectric constant and yellowing resistance.
<Table 1>

From Table 1, it can be seen that the dielectric constants of 1 GHz and 10 GHz are less than 3.0 from Examples 1 to 4, and the smaller the number of DMS units, the lower the dielectric constant. It is considered that this is because Example 1 has more cage-type silsesquioxane components and more voids in the film. Further, when the sample of Example 3 was measured using a 1 GHz resonator, it was 2.3. This has a low viscosity before curing and is suitable for applications that impregnate glass cloth. Comparing Example 2 and Example 5, all the polysiloxane chains-SiMe ₂ -has a lower dielectric constant, so Example 2 is a little better as a low-dielectric material, but the adhesion to the substrate is a little better. A substrate having a low dielectric constant can also be obtained by using —SiHMe— for adjusting the above. Further, from the degree of yellowing, it can be seen that Examples 1 to 5 are superior in heat resistance as compared with Comparative Examples.

The composition for a low dielectric constant and high heat resistant substrate of the present invention has a low dielectric constant at 1 GHz and 10 GHz and has high heat resistance, so that it can be used as a composition for forming an electronic circuit board and its peripheral members used in a high frequency region. It is preferably used.

Claims (8)

It contains a polysiloxane copolymer composed of a cage-type silsesquioxane repeating unit represented by the formula (A) and a chain siloxane repeating unit represented by the formula (B), and in the polysiloxane copolymer, the above-mentioned cage. The molar ratio of the repeating unit of the type silsesquioxane (A) to the repeating unit of the chain siloxane (B) is 1: 1 to 1:10, and the dielectric constant of the polysiloxane copolymer at 1 GHz and 10 GHz is A composition for a low dielectric constant and high heat resistant substrate, both of which are 3.0 or less.

In formula (A),
^R0 is independently an aryl having 6 to 20 carbon atoms or a cycloalkyl having 5 to 6 carbon atoms, and in the aryl having 6 to 20 carbon atoms and the cycloalkyl having 5 to 6 carbon atoms, at least one hydrogen is contained. It may be replaced with a halogen or an alkyl having 1 to 20 carbon atoms;
^R1 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, or alkyl having 1 to 40 carbon atoms. At least one hydrogen is replaced by a halogen or an alkyl having 1 to 20 carbon atoms in the aryl in an aryl having 6 to 20 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, and an aryl alkyl having 7 to 40 carbon atoms. Alternatively, in the alkylene in the arylalkyl having 7 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- is -O-, -CH = CH-, or. An alkyl having 5 to 20 carbon atoms may be replaced with a cycloalkylene having 1 to 40 carbon atoms, and at least one hydrogen may be replaced with a halogen, and at least one -CH _2- may be replaced with -O- or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms;
x is greater than or equal to 1;
In formula (B),
^R2 is independently composed of hydrogen, vinyl, allyl, hydroxyl group, aryl having 6 to 20 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, arylalkyl having 7 to 40 carbon atoms, or alkyl having 1 to 40 carbon atoms. At least one hydrogen is replaced by a halogen or an alkyl having 1 to 20 carbon atoms in the aryl in an aryl having 6 to 20 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, and an aryl alkyl having 7 to 40 carbon atoms. Alternatively, in the alkylene in the arylalkyl having 7 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- is -O-, -CH = CH-, or. It may be replaced with a cycloalkylene having 5 to 20 carbon atoms, or in an alkyl having 1 to 40 carbon atoms, at least one hydrogen may be replaced with a halogen, and at least one -CH _2- may be replaced with -O- or carbon. May be replaced with the number 5-20 cycloalkylene;
y is 1 or more. The composition for a low dielectric constant and high heat resistant substrate according to claim 1, wherein the weight average molecular weight of the polysiloxane copolymer is in the range of 2,000 to 10,000,000. The composition for a low dielectric constant and high heat resistant substrate according to claim 1 or 2, wherein the glass transition temperature of the polysiloxane copolymer is 0 ° C. or higher. The low dielectric constant according to any one of claims 1 to 3, wherein the crosslink density n of the polysiloxane copolymer obtained from the calculation formula represented by the formula (α) is 150 mol / m ³ or more. Composition for heat-resistant substrate.
n = E'/ 3RT ... (α)
In formula (α), n: crosslink density (mol / m ³ ), E': storage elastic modulus (Pa), R: gas constant ((Pa · m ³ ) / K · mol)), T: temperature (K). ). The composition for a low dielectric constant and high heat resistant substrate according to any one of claims 1 to 4, further comprising a glass cloth as a reinforcing material. The composition for a low dielectric constant and high heat resistant substrate according to claim 5, wherein the reinforcing material is a low dielectric glass cloth. A low-dielectric substrate, an interlayer insulating film for a low-dielectric substrate, or a low-dielectric coating material comprising the composition for a low-dielectric-constant high-heat-resistant substrate according to any one of claims 1 to 6. A low-dielectric substrate, an interlayer insulating film for a low-dielectric substrate, an electronic circuit using a low-dielectric coating material, a sensor, and an antenna comprising the composition for a low-dielectric-constant high-heat-resistant substrate according to any one of claims 1 to 6. , Radars, or electronic devices that use them.

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