JP6166146B2 - Electromagnetic shield sheet - Google Patents

Description

  The present invention relates to an electromagnetic wave shielding sheet.

In recent years, with the advancement of electronics technology, various electronic devices such as home appliances and mobile phones have been widely used, and technologies for connecting these electronic devices wirelessly have also been developed. However, there are concerns about the influence of electromagnetic waves on others, such as other electronic devices malfunctioning due to electromagnetic waves generated from the electronic devices.
Therefore, conventionally, an electromagnetic shielding material that shields (shields) electromagnetic waves is known in order to reduce the influence of electromagnetic waves. For example, there is known an electromagnetic wave shielding material in which a shield layer made of metal is formed on the surface of a fiber fabric such as a nonwoven fabric by a vacuum deposition method, an ion plating method, a sputtering method, an electroless metal plating method, or the like.

In the conventional electromagnetic shielding material provided with a shield layer made of metal, the flexibility and extensibility of the shield layer made of metal is not sufficient. There was a possibility that the electromagnetic wave shielding property of the part where the crack or the like occurred was lowered.
In order to solve the above problem, Patent Document 1 discloses an electromagnetic wave shielding material including a shield layer made of a metal-containing resin. However, even the shielding material uses metal particles and conductive fillers, and thus has a problem of poor flexibility and powder deposition from the end face.

JP 2003-69284 A

  An object of the present invention is to provide an electromagnetic wave shielding sheet excellent in flexibility and extensibility.

（式中、Ｍは、水素原子、有機遊離基又は無機遊離基であり、ｍ’はＭの価数である。
Ｒ^１３及びＲ^１４は、それぞれ独立に、炭化水素基又は−（Ｒ^１５Ｏ）_ｒ−Ｒ^１６で表わされる基である。
Ｒ^１５はそれぞれ独立に炭化水素基又はシリレン基であり、Ｒ^１６は水素原子、炭化水素基又はＲ^１７ _３Ｓｉ−で表わされる基であり、ｒは１以上の整数である。
Ｒ^１７はそれぞれ独立に炭化水素基である。）
７．前記組成物がフェノール性水酸基を有する化合物を含む１〜６のいずれかに記載の電磁波シールドシート。
８．前記組成物中のフェノール性水酸基を有する化合物の含有量が５〜６０重量％である７に記載の電磁波シールドシート。
９．前記組成物がナフタレンスルホン酸を含む１〜８のいずれかに記載の電磁波シールドシート。
１０．前記組成物中のπ共役系導電性高分子の含有量が５〜３０重量％である１〜９のいずれかに記載の電磁波シールドシート。
１１．厚みが０．１５ｍｍ以上である１〜１０のいずれかに記載の電磁波シールドシート。
１２．キャスト法を用いて形成した１〜１１のいずれかに記載の電磁波シールドシート。
１３．溶剤に溶解可能なπ共役系導電性高分子を含む組成物を用いてキャスト法で電磁波シールドシートを形成する工程を含む電磁波シールドシートの製造方法。
１４．溶剤に溶解可能なπ共役系導電性高分子を含む組成物をスプレー法を用いて塗工することで表面に電磁波シールドシート層を形成した成形品。 According to the present invention, the following electromagnetic wave shielding sheet and the like are provided.
1. An electromagnetic wave shielding sheet formed from a composition containing a π-conjugated conductive polymer soluble in a solvent,
An electromagnetic wave shielding sheet having a surface resistance of 5Ω / □ or less.
2. The electromagnetic wave shielding sheet according to 1, which can shield an electric field component of an electromagnetic wave of 0.15 MHz by 40 dB or more.
3. The electromagnetic wave shielding sheet according to 1 or 2, which can shield an electrolytic component of an electromagnetic wave of 10 MHz by 60 dB or more.
4). The electromagnetic wave shielding sheet according to any one of 1 to 3, which does not contain a metal component.
5. The electromagnetic wave shielding sheet according to any one of 1 to 4, wherein the π-conjugated conductive polymer is a composite of substituted or unsubstituted polyaniline.
6). 6. The electromagnetic wave shielding sheet according to 5, wherein the substituted or unsubstituted polyaniline complex is a complex of unsubstituted polyaniline and a sulfosuccinic acid derivative represented by the following formula (III).

(In the formula, M is a hydrogen atom, an organic free radical or an inorganic free radical, and m ′ is the valence of M.
R ¹³ and R ¹⁴ are each independently a hydrocarbon group or a group represented by — (R ¹⁵ O) _r —R ¹⁶ .
R ¹⁵ is independently a hydrocarbon group or a silylene group, R ¹⁶ is a hydrogen atom, a hydrocarbon group or a group represented by R ¹⁷ ₃ Si—, and r is an integer of 1 or more.
R ¹⁷ is each independently a hydrocarbon group. )
7). The electromagnetic wave shielding sheet according to any one of 1 to 6, wherein the composition contains a compound having a phenolic hydroxyl group.
8). 8. The electromagnetic wave shielding sheet according to 7, wherein the content of the compound having a phenolic hydroxyl group in the composition is 5 to 60% by weight.
9. The electromagnetic wave shielding sheet according to any one of 1 to 8, wherein the composition contains naphthalenesulfonic acid.
10. The electromagnetic wave shielding sheet according to any one of 1 to 9, wherein the content of the π-conjugated conductive polymer in the composition is 5 to 30% by weight.
11. The electromagnetic wave shielding sheet according to any one of 1 to 10 having a thickness of 0.15 mm or more.
12 The electromagnetic wave shielding sheet according to any one of 1 to 11 formed by using a casting method.
13. The manufacturing method of the electromagnetic wave shield sheet including the process of forming an electromagnetic wave shield sheet by the casting method using the composition containing (pi) conjugated system conductive polymer soluble in a solvent.
14 A molded article in which an electromagnetic wave shielding sheet layer is formed on the surface by coating a composition containing a π-conjugated conductive polymer that can be dissolved in a solvent using a spray method.

  According to the present invention, an electromagnetic wave shielding sheet excellent in flexibility and extensibility can be provided.

It is a figure which shows the apparatus used for evaluation of the shielding performance of an electromagnetic wave shield sheet.

[Electromagnetic wave shield sheet]
The electromagnetic wave shielding sheet of the present invention is a sheet formed from a composition containing a π-conjugated conductive polymer that can be dissolved in a solvent, and has a surface resistance of 5Ω / □ or less.
A sheet formed from a composition containing a π-conjugated conductive polymer that can be dissolved in a solvent has the above-mentioned surface resistance, and can efficiently conduct a current induced from an electric field component of an electromagnetic wave. Therefore, the electromagnetic wave absorbing sheet of the present invention does not need to contain a metal component and is excellent in flexibility and extensibility.
The lower limit of the surface resistance of the electromagnetic wave shielding sheet is not particularly limited, but is, for example, 0.01Ω / □. The surface resistance of the shield sheet can be measured by using a commercially available surface measuring device based on JIS K-7194.

The electromagnetic wave shielding sheet of the present invention can shield an electric field component of an electromagnetic wave of 0.15 MHz preferably 40 dB or more.
The electromagnetic wave shielding sheet of the present invention can shield an electric field component of an electromagnetic wave of 10 MHz preferably 60 dB or more.
The electromagnetic shielding effect of the electromagnetic shielding sheet can be evaluated by the KCE method.

The electromagnetic wave shielding sheet of the present invention preferably has a thickness of 0.15 mm or more, more preferably 0.2 mm or more.
Although the upper limit of the thickness of a shield sheet is not specifically limited, For example, it is 2.0 mm. The thickness of the shield sheet can be measured by using, for example, a contact-type film thickness meter.

The electromagnetic wave shielding sheet of the present invention is a sheet formed from a composition containing a π-conjugated conductive polymer that can be dissolved in a solvent. The composition that forms the shielding sheet is (1) π that is soluble in a solvent. A conjugated conductive polymer may be included, and (2) a solvent, (3) a compound having a phenolic hydroxyl group, and (4) a heat-resistant stabilizer may be further included.
Hereinafter, these components will be described.

(1) π-conjugated conductive polymer soluble in solvent The π-conjugated conductive polymer soluble in the solvent is preferably a substituted or unsubstituted polyaniline complex, and the polyaniline complex is substituted or substituted. It is a composite in which an unsubstituted polyaniline molecule is doped with a dopant.

The weight average molecular weight (hereinafter referred to as molecular weight) of the polyaniline molecule is preferably 20,000 or more. If the molecular weight is less than 20,000, the strength and stretchability of the shield sheet may be reduced. Molecular weight becomes like this. Preferably it is 20,000-500,000, More preferably, it is 20,000-300,000, More preferably, it is 20,000-200,000. The molecular weight is, for example, 50,000 to 200,000, 53,000 to 200,000.
Here, the weight average molecular weight is not the molecular weight of the polyaniline complex but the molecular weight of the polyaniline molecule.

The molecular weight distribution of the polyaniline molecule is preferably 1.5 or more and 20.0 or less, more preferably 1.5 or more and 5.0 or less, still more preferably 1.5 or more and 4.5 or less, and particularly preferably. Is 1.5 or more and 4.0 or less, and most preferably 1.5 or more and 3.6 or less. Here, the molecular weight distribution is not the molecular weight distribution of the polyaniline complex, but the molecular weight distribution of the polyaniline molecules, as described above.
The molecular weight distribution is a value represented by weight average molecular weight / number average molecular weight, and the molecular weight distribution is preferably smaller from the viewpoint of electrical conductivity. Moreover, the said weight average molecular weight and molecular weight distribution are obtained as a polystyrene conversion value which can be measured with a gel permeation chromatograph (GPC).

Examples of the substituent of the substituted polyaniline include linear or branched hydrocarbon groups such as methyl group, ethyl group, hexyl group and octyl group; alkoxy groups such as methoxy group and ethoxy group; aryloxy groups such as phenoxy group; Halogenated hydrocarbons such as a fluoromethyl group (—CF ₃ group) are exemplified.
The polyaniline molecule is preferably an unsubstituted polyaniline molecule from the viewpoint of versatility and economy.

  Examples of the dopant of the polyaniline complex include Bronsted acid ions generated from Bronsted acid or Bronsted acid salts, preferably organic acid ions generated from organic acids or salts of organic acids, and more preferably the following formula: It is an organic acid ion generated from the compound (proton donor) represented by (I).

M (XARn) m (I)
M in the formula (I) is a hydrogen atom, an organic radical or an inorganic radical.
Examples of the organic free radical include a pyridinium group, an imidazolium group, and an anilinium group. Examples of the inorganic free radical include lithium, sodium, potassium, cesium, ammonium, calcium, magnesium, and iron.
X in the formula (I) is an anionic group, for example, —SO ₃ ^— group, —PO ₃ ^{2 —} group, —PO ₄ (OH) ^{2 —} , —OPO ₃ ^{2 —} group, —OPO ₂ (OH) ^—. group, -COO ^- group, and preferably -SO ₃ ^- is a group.

A in formula (I) is a substituted or unsubstituted hydrocarbon group.
The hydrocarbon group is a chain or cyclic saturated aliphatic hydrocarbon group, a chain or cyclic unsaturated aliphatic hydrocarbon group, or an aromatic hydrocarbon group.

Examples of the chain saturated aliphatic hydrocarbon group include a linear or branched saturated aliphatic hydrocarbon group. Carbon number is 1 or more and 24 or less, for example, and 2 or more and 8 or less.
Examples of the cyclic saturated aliphatic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The cyclic saturated aliphatic hydrocarbon group may be a condensation of a plurality of cyclic saturated aliphatic hydrocarbon groups. Examples thereof include a norbornyl group, an adamantyl group, and a condensed adamantyl group.

  Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the chain unsaturated aliphatic hydrocarbon include a linear or branched alkenyl group.

  Here, when A is a substituted hydrocarbon group, the substituent is alkyl group, cycloalkyl group, vinyl group, allyl group, aryl group, alkoxy group, halogen group, hydroxy group, amino group, imino group, nitro group. Group, silyl group or ester group.

R in formula (I) is bonded to A, and each independently represents —H, —R ¹ , —OR ¹ , —COR ¹ , —COOR ¹ , — (C═O) — (COR ¹ ). Or a substituent represented by-(C = O)-(COOR ¹ ), wherein R ¹ is a hydrocarbon group, silyl group, alkylsilyl group,-(R ² O) x -R which may contain a substituent. ³ or-(OSiR ³ ₂ ) x -OR ³ (R ² is independently an alkylene group, R ³ is each independently a hydrocarbon group, and x is an integer of 1 or more).

Examples of the hydrocarbon group for R ¹ include a chain or cyclic saturated aliphatic hydrocarbon group, a chain or cyclic unsaturated aliphatic hydrocarbon group, and an aromatic hydrocarbon group. Specific examples include methyl group, ethyl group, linear or branched butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, pentadecyl group and eicosanyl group. The substituent of the hydrocarbon group is an alkyl group, a cycloalkyl group, a vinyl group, an allyl group, an aryl group, an alkoxy group, a halogen group, a hydroxy group, an amino group, an imino group, a nitro group, or an ester group. The hydrocarbon group for R ³ is the same as R ¹ .

Examples of the alkylene group for R ² include a methylene group, an ethylene group, and a propylene group.
N in the formula (I) is an integer of 1 or more, and m in the formula (I) is a valence of M / a valence of X.

（式中、Ｍ及びＸは、式（Ｉ）と同様である。Ｘは、−ＳＯ_３ ⁻基が好ましい。） As the compound represented by the formula (I), dialkylbenzenesulfonic acid, dialkylnaphthalenesulfonic acid, or a compound containing two or more ester bonds is preferable.
The compound containing two or more ester bonds is more preferably a sulfophthalic acid ester or a compound represented by the following formula (II).

(In the formula, M and X are the same as those in formula (I). X is preferably a —SO ₃ ^— group.)

R ⁴ , R ⁵ and R ^{6 in} formula (II) are each independently a hydrogen atom, a hydrocarbon group or an R ⁹ ₃ Si— group (wherein R ⁹ is a hydrocarbon group, and three R ⁹ are They may be the same or different).
Examples of the hydrocarbon group when R ⁴ , R ⁵ and R ⁶ are hydrocarbon groups include linear or branched alkyl groups having 1 to 24 carbon atoms, aryl groups containing aromatic rings, and alkylaryl groups. It is done.
The hydrocarbon group for R ⁹ is the same as in the case of R ⁴ , R ⁵ and R ⁶ .

R ⁷ and R ^{8 in} formula (II) are each independently a hydrocarbon group or — (R ¹⁰ O) _q —R ¹¹ group [wherein R ¹⁰ is a hydrocarbon group or a silylene group, and R ¹¹ is A hydrogen atom, a hydrocarbon group, or R ¹² ₃ Si— (R ¹² is a hydrocarbon group, three R ¹² may be the same or different, and q is an integer of 1 or more]. .

Examples of the hydrocarbon group when R ⁷ and R ⁸ are hydrocarbon groups include a chain or cyclic saturated aliphatic hydrocarbon group, a chain or cyclic unsaturated aliphatic hydrocarbon group, or an aromatic hydrocarbon group Etc. Examples thereof include a linear or branched alkyl group having 1 to 24 carbon atoms, preferably 4 to 24 carbon atoms, an aryl group containing an aromatic ring, and an alkylaryl group.
Specific examples of the hydrocarbon group when R ⁷ and R ⁸ are hydrocarbon groups include, for example, a linear or branched butyl group, pentyl group, hexyl group, octyl group, and decyl group. Preferably, it is a linear or branched octyl group. More preferably, it is a 2-ethylhexyl group.

Examples of the hydrocarbon group in R ⁷ and R ⁸ when R ¹⁰ is a hydrocarbon group include a linear or branched alkylene group having 1 to 24 carbon atoms, an arylene group containing an aromatic ring, an alkylarylene group, An arylalkylene group. In addition, the hydrocarbon group in the case where R ¹¹ and R ¹² in R ⁷ and R ⁸ are hydrocarbon groups is the same as in the case of R ⁴ , R ⁵ and R ⁶ , and q is 1 to 10 Preferably there is.

（式中、Ｘは式（Ｉ）と同様である。） Specific examples of the compound represented by the formula (II) when R ⁷ and R ⁸ are — (R ¹⁰ O) _q —R ¹¹ group include two compounds represented by the following formulas.

(Wherein X is the same as in formula (I).)

（式中、Ｍは、式（Ｉ）と同様である。ｍ’は、Ｍの価数である。） The compound represented by the above formula (II) is more preferably a sulfosuccinic acid derivative represented by the following formula (III).

(In the formula, M is the same as in formula (I). M ′ is the valence of M.)

R ¹³ and R ^{14 in} the formula (III) are each independently a hydrocarbon group or — (R ¹⁵ O) _r —R ¹⁶ group [wherein R ¹⁵ is independently a hydrocarbon group or a silylene group, R ¹⁶ is a hydrogen atom, a hydrocarbon group, or an R ¹⁷ ₃ Si— group (wherein R ¹⁷ is independently a hydrocarbon group, and r is an integer of 1 or more).

The hydrocarbon group when R ¹³ and R ¹⁴ are hydrocarbon groups is the same as R ⁷ and R ⁸ . For example, a linear saturated aliphatic hydrocarbon group or a linear or branched alkyl group having 4 to 24 carbon atoms. Specific examples include a linear or branched butyl group, pentyl group, hexyl group, octyl group, and decyl group. Preferably, it is a linear or branched octyl group. More preferably, it is a 2-ethylhexyl group.
In R ¹³ and R ¹⁴ , the hydrocarbon group when R ¹⁵ is a hydrocarbon group is the same as R ¹⁰ described above. In R ¹³ and R ¹⁴ , the hydrocarbon group in the case where R ¹⁶ and R ¹⁷ are hydrocarbon groups is the same as R ⁴ , R ⁵ and R ⁶ described above.
r is preferably from 1 to 10.

Specific examples in the case where R ¹³ and R ¹⁴ are — (R ¹⁵ O) _r —R ¹⁶ groups are the same as those for — (R ¹⁰ O) _q —R ¹¹ in R ⁷ and R ⁸ .
The hydrocarbon group for R ¹³ and R ¹⁴ is the same as R ⁷ and R ⁸ and is preferably a butyl group, a hexyl group, a 2-ethylhexyl group, or a decyl group.

It is known that the conductivity of the polyaniline complex and the solubility in a solvent can be controlled by changing the structure of the above dopant (Japanese Patent No. 338466). In the present invention, an optimum dopant can be selected according to required characteristics for each application.
As the compound represented by the formula (I), di-2-ethylhexylsulfosuccinic acid and sodium di-2-ethylhexylsulfosuccinate are preferable. As the dopant of the present invention, di-2-ethylhexyl sulfosuccinate ion is preferable.

  It can be confirmed that the dopant of the polyaniline complex is doped to the substituted or unsubstituted polyaniline by ultraviolet / visible / near-infrared spectroscopy or X-ray photoelectron spectroscopy. As long as it has sufficient acidity to generate odor, it can be used without any restriction on the chemical structure.

The polyaniline complex can be produced by a well-known production method. For example, the polyaniline complex contains a proton donor, phosphoric acid, and an emulsifier different from the proton donor. It can be produced by chemical oxidative polymerization of substituted anilines. Moreover, it can manufacture by adding an oxidation polymerization agent in the solution which contains the emulsifier different from a substituted or unsubstituted aniline, a proton donor, phosphoric acid, and a proton donor, and has two liquid phases.
In addition, it is thought that the emulsifier plays the role which prevents the phase inversion mentioned later. When a polyaniline complex is produced by chemically oxidatively polymerizing a substituted or unsubstituted aniline in a solution containing a proton donor and phosphoric acid and having two liquid phases, compared to the case where hydrochloric acid is used instead of phosphoric acid. , Low molecular weight components will increase. From the state during polymerization when phosphoric acid is used, it is considered that the two liquid phases cause phase inversion during the polymerization. And it is thought that this phase inversion increases the low molecular weight component. This phenomenon of phase inversion is a phenomenon in which the liquid phase that was a continuous phase changes to a dispersed phase, and the other liquid phase that was a dispersed phase changes to a continuous phase.

Here, the “solution having two liquid phases” means a state in which two liquid phases that are incompatible with each other exist in the solution. For example, it means a state in which a “high polarity solvent phase” and a “low polarity solvent phase” exist in the solution.
Further, “a solution having two liquid phases” includes a state in which one liquid phase is a continuous phase and the other liquid phase is a dispersed phase. For example, a state where the “high polarity solvent phase” is a continuous phase and the “low polarity solvent phase” is a dispersed phase, and the “low polarity solvent phase” is a continuous phase and the “high polarity solvent phase” is a dispersed phase. Is included.

  As the high polarity solvent used in the method for producing the polyaniline complex, water is preferable, and as the low polarity solvent, aromatic hydrocarbons such as toluene and xylene are preferable.

  The proton donor is preferably a compound represented by the above formula (I), more preferably a compound represented by the above formula (II), and still more preferably a compound represented by the above formula (III).

  The emulsifier can be either an ionic emulsifier whose hydrophilic part is ionic or a nonionic emulsifier whose non-ionic hydrophilic part is used, or a mixture of one or more emulsifiers. May be used.

Examples of the ionic emulsifier include a cationic emulsifier, an anionic emulsifier, and a zwitter emulsifier.
Specific examples of the anionic emulsifier (anionic emulsifier) include fatty acids, disproportionated rosin soaps, higher alcohol esters, polyoxyethylene alkyl ether phosphates, alkenyl succinic acids, sarcosinates, and salts thereof.
Specific examples of the cationic emulsifier (cationic emulsifier) include alkyl dimethyl benzyl ammonium salt and alkyl trimethyl ammonium salt.
Specific examples of the zwitterionic emulsifier (both ion emulsifier) include alkyl betaine type, alkyl amide betaine type, amino acid type, and amine oxide type.
Specific examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polypropylene glycol polyethylene glycol ether, polyoxyethylene glycerol borate fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

Of the above emulsifiers, anionic emulsifiers and nonionic emulsifiers are preferred.
As the anionic emulsifier, an anionic emulsifier having a phosphate ester structure is more preferable. Further, as the nonionic emulsifier, a nonionic emulsifier having a polyoxyethylene sorbitan fatty acid ester structure is more preferable.

The amount of the proton donor used is preferably 0.1 to 0.5 mol, more preferably 0.3 to 0.45 mol, and still more preferably 0.35 to 0, relative to 1 mol of the aniline monomer. .4 mol.
When the amount of the proton donor used is larger than the above range, for example, there is a possibility that the “high-polar solvent phase” and the “low-polar solvent phase” cannot be separated after completion of polymerization.

  The use concentration of phosphoric acid is 0.3 to 6 mol / L, more preferably 1 to 4 mol / L, still more preferably 1 to 2 mol / L with respect to the highly polar solvent.

The amount of the emulsifier used is preferably 0.001 to 0.1 mol, more preferably 0.002 to 0.02 mol, and still more preferably 0.003 to 0.01 mol with respect to 1 mol of the aniline monomer. is there.
When the amount of the emulsifier used is larger than the above range, the “high polar solvent phase” and the “low polar solvent phase” may not be separated after the completion of the polymerization.

The oxidizing agent used for chemical oxidative polymerization (hereinafter sometimes referred to as "oxidizing polymerizer") includes peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, and hydrogen peroxide; ammonium dichromate, perchloric acid. Ammonium, potassium iron sulfate (III), iron trichloride (III), manganese dioxide, iodic acid, potassium permanganate, iron paratoluenesulfonate, etc. can be used, and persulfates such as ammonium persulfate are preferred.
These oxidizing agents may be used alone or in combination of two or more.

The amount of the oxidizing agent used is preferably 0.05 to 1.8 mol, more preferably 0.8 to 1.6 mol, still more preferably 1.2 to 1.4 mol, relative to 1 mol of the aniline monomer. It is. A sufficient degree of polymerization can be obtained by setting the amount of the oxidizing agent used within the above range. Further, since aniline is sufficiently polymerized, it is easy to recover the liquid separation, and there is no possibility that the solubility of the polymer is lowered.
The polymerization temperature is usually −5 to 60 ° C., preferably −5 to 40 ° C. The polymerization temperature may be changed during the polymerization reaction. Side reactions can be avoided when the polymerization temperature is within this range.

Specifically, the polyaniline complex can be produced by the following method.
A solution in which a proton donor and an emulsifier are dissolved in toluene is placed in a separable flask placed in a stream of inert atmosphere such as nitrogen, and a substituted or unsubstituted aniline is added to the solution. Thereafter, phosphoric acid containing no chlorine is added to the solution, and the solution temperature is cooled.
After the solution internal temperature is cooled, stirring is performed. A solution in which ammonium persulfate is dissolved in phosphoric acid is dropped using a dropping funnel and reacted. Thereafter, the solution temperature is raised and the reaction is continued. After completion of the reaction, the aqueous phase separated into two phases by standing is separated. Toluene is added to the organic phase side and washed with phosphoric acid and ion-exchanged water to obtain a polyaniline complex (protonated polyaniline) toluene solution.
Some insolubles contained in the obtained complex solution are removed, and a toluene solution of the polyaniline complex is recovered. The solution is transferred to an evaporator, heated and decompressed to evaporate and remove volatile components, whereby a polyaniline complex is obtained.

Polyaniline molecules that are not polyaniline complexes can be produced by well-known methods. A specific example is the production method described in JP-A-3-28229. While maintaining the temperature of aniline in a solvent at a temperature of, for example, 5 ° C. or lower in the presence of a protonic acid, one mole of oxidant and one molecule of oxidant are reduced per mole of aniline. An equivalent amount defined as the amount divided by the number of electrons required for the reaction, for example, 2 equivalents or more, is gradually added to bring about the oxidized polymer of aniline doped with the protonic acid, and then the polymer. Can be produced by undoping with a basic substance.
In addition, a polyaniline molecule solution can be produced by mixing the polyaniline complex described above with a 1M aqueous sodium hydroxide solution to produce a dedoped polyaniline powder and dissolving it in NMP (N-methylpyrrolidone). .

The content of the π-conjugated conductive polymer that can be dissolved in the solvent in the composition forming the shield sheet is preferably 5% by weight to 50% by weight, more preferably 10% by weight to 30% by weight. .
When the content of the π-conjugated conductive polymer is in the above range, for example, the thickness of the shield sheet can be 0.2 mm or more.

(2) Solvent The solvent may be an organic solvent or an inorganic solvent such as water, and may be a single type or a mixed solvent of two or more types. An organic solvent is preferable.
The organic solvent may be a water-soluble organic solvent or an organic solvent that is substantially immiscible with water (water-immiscible organic solvent).

  The water-soluble organic solvent may be a protic polar solvent or an aprotic polar solvent. For example, alcohols such as isopropanol, 1-butanol, 2-butanol, 2-pentanol, and benzyl alcohol; ketones such as acetone; Ethers such as tetrahydrofuran and dioxane; aprotic polar solvents such as N-methylpyrrolidone and the like.

  Examples of the water-immiscible organic solvent include hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and tetralin; halogen-containing solvents such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, and tetrachloroethane; ethyl acetate, Examples thereof include ester solvents such as isobutyl acetate and n-butyl acetate, ketone solvents such as methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone and cyclohexanone, and ether solvents such as cyclopentyl methyl ether. Of these, toluene, xylene, methyl isobutyl ketone (MIBK), chloroform, trichloroethane, and ethyl acetate are preferred because of their excellent solubility.

  A combination of a water-soluble organic solvent and a water-immiscible organic solvent may be used as a mixed solvent of two or more. For example, when using toluene, isopropyl alcohol and methyl isobutyl ketone as the solvent, the content in the composition should be 20 to 50% by weight, 0.1 to 15% by weight and 0.1 to 40% by weight, respectively. Can do.

(3) Compound having phenolic hydroxyl group The composition forming the shield layer preferably contains a compound having a phenolic hydroxyl group. When the composition contains a compound having a phenolic hydroxyl group, the solubility of the π-conjugated conductive polymer can be improved.
The compound having a phenolic hydroxyl group is a polymer compound composed of a compound having one phenolic hydroxyl group, a compound having a plurality of phenolic hydroxyl groups, and a repeating unit having one or more phenolic hydroxyl groups.

（式中、ｎは１〜５の整数であり、好ましくは１〜３であり、より好ましくは１である。
Ｒは、炭素数１〜２０のアルキル基、アルケニル基、シクロアルキル基、アリール基、アルキルアリール基又はアリールアルキル基である。） The compound having one phenolic hydroxyl group is preferably a compound represented by the following formulas (A), (B) and (C).

(In formula, n is an integer of 1-5, Preferably it is 1-3, More preferably, it is 1.
R is an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group. )

  In the phenolic compound represented by the formula (A), the substitution position of -OR is preferably a meta position or a para position with respect to the phenolic hydroxyl group. By making the substitution position of —OR the meta position or the para position, the steric hindrance of the phenolic hydroxyl group is reduced, and the conductivity of the composition can be further increased.

  Specific examples of the phenolic compound represented by the formula (A) include methoxyphenol (for example, 4-methoxyphenol), ethoxyphenol, propoxyphenol, isopropoxyphenol, butyloxyphenol, isobutyloxyphenol, and tertiary butyloxyphenol. Can be mentioned.

（式中、ｎは０〜７の整数であり、好ましくは０〜３であり、より好ましくは１である。
Ｒは、それぞれ炭素数１〜２０のアルキル基、アルケニル基、アルキルチオ基、炭素数３〜１０のシクロアルキル基、炭素数６〜２０のアリール基、アルキルアリール基又はアリールアルキル基である。）
式（Ｂ）で表わされるフェノール性化合物の具体例としては、ヒドロキシナフタレンが挙げられる。

(In formula, n is an integer of 0-7, Preferably it is 0-3, More preferably, it is 1.
R is an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkylthio group, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, or an arylalkyl group. )
Specific examples of the phenolic compound represented by the formula (B) include hydroxynaphthalene.

（式中、ｎは１〜５の整数であり、好ましくは１〜３であり、より好ましくは１である。
Ｒは、それぞれ炭素数１〜２０のアルキル基、アルケニル基、アルキルチオ基、炭素数３〜１０のシクロアルキル基、炭素数６〜２０のアリール基、アルキルアリール基又はアリールアルキル基である。）
式（Ｃ）で表わされる化合物の具体例としては、ｏ−，ｍ−若しくはｐ−クレゾール、ｏ−，ｍ−若しくはｐ−エチルフェノール、ｏ−，ｍ−若しくはｐ−プロピルフェノール（例えば４−イソプロピルフェノール）、ｏ−，ｍ−若しくはｐ−ブチルフェノール、ｏ−，ｍ−若しくはｐ−ペンチルフェノール（例えば、４−ｔｅｒｔ−ペンチルフェノール）が挙げられる。

(In formula, n is an integer of 1-5, Preferably it is 1-3, More preferably, it is 1.
R is an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkylthio group, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, or an arylalkyl group. )
Specific examples of the compound represented by the formula (C) include o-, m- or p-cresol, o-, m- or p-ethylphenol, o-, m- or p-propylphenol (for example, 4-isopropyl). Phenol), o-, m- or p-butylphenol, o-, m- or p-pentylphenol (for example, 4-tert-pentylphenol).

Regarding R in formulas (A), (B), and (C), examples of the alkyl group having 1 to 20 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl.
Examples of the alkenyl group include groups having an unsaturated bond in the molecule of the alkyl group described above.
Examples of the cycloalkyl group include cyclopentane and cyclohexane.
Examples of the aryl group include phenyl and naphthyl.
Examples of the alkylaryl group and the arylalkyl group include groups obtained by combining the above-described alkyl group and aryl group.

（式中、Ｒは炭化水素基、ヘテロ原子含有炭化水素基、ハロゲン原子、カルボン酸基、アミノ基、ＳＨ基、スルホン酸基、又は水酸基であり、複数のＲはそれぞれ互いに同一であっても異なっていてもよい。ｎは０〜６の整数である。） Although the example of the compound which has one said phenolic hydroxyl group was shown, a phenol, o-, m- or p-chlorophenol, a salicylic acid, hydroxybenzoic acid is mentioned as a specific example of substituted phenols. Specific examples of the compound having a plurality of phenolic hydroxyl groups include catechol, resorcinol, and a compound represented by the following formula (D).

(In the formula, R is a hydrocarbon group, a hetero atom-containing hydrocarbon group, a halogen atom, a carboxylic acid group, an amino group, an SH group, a sulfonic acid group, or a hydroxyl group. May be different, n is an integer from 0 to 6.)

The phenolic compound represented by the formula (D) preferably has two or more hydroxyl groups that are not adjacent to each other.
Specific examples of the phenolic compound represented by the formula (D) include 1,6 naphthalenediol, 2,6 naphthalenediol, and 2,7 naphthalenediol.

  Specific examples of the polymer compound composed of a repeating unit having one or more phenolic hydroxyl groups include phenol resin, polyphenol, and poly (hydroxystyrene).

Content of the compound which has a phenolic hydroxyl group in the composition which forms an electromagnetic wave shield sheet becomes like this. Preferably it is 5 to 60 weight%, More preferably, it is 15 to 40 weight%.
When the content of the compound having a phenolic hydroxyl group is in the above range, the solvent can be prevented from remaining and precipitating in the obtained shield sheet.

(4) Heat Stabilizer The heat stabilizer is an acidic substance or a salt of an acidic substance, and the acidic substance may be either an organic acid (an acid of an organic compound) or an inorganic acid (an acid of an inorganic compound).
The acidic substance that is a heat-resistant stabilizer is preferably an organic acid, more preferably an organic acid having one or more sulfonic acid groups, carboxy groups, phosphoric acid groups, or phosphonic acid groups, and more preferably sulfonic acid. An organic acid having one or more groups. Examples of salts of acidic substances that are heat stabilizers include salts of these acidic substances.

The organic acid having one or more sulfonic acid groups is preferably a cyclic, linear or branched alkylsulfonic acid, substituted or unsubstituted aromatic sulfonic acid, or polysulfonic acid having one or more sulfonic acid groups.
Examples of the alkylsulfonic acid include methanesulfonic acid, ethanesulfonic acid, and di-2-ethylhexylsulfosuccinic acid. The alkyl group here is preferably a linear or branched alkyl group having 1 to 18 carbon atoms.
Examples of the aromatic sulfonic acid include a sulfonic acid having a benzene ring, a sulfonic acid having a naphthalene skeleton, a sulfonic acid having an anthracene skeleton, a substituted or unsubstituted benzenesulfonic acid, a substituted or unsubstituted naphthalenesulfonic acid, and a substituted Alternatively, unsubstituted anthracene sulfonic acid may be mentioned, and naphthalene sulfonic acid is preferable. Specific examples include naphthalene sulfonic acid, dodecylbenzene sulfonic acid, and anthraquinone sulfonic acid.
Here, the substituent is, for example, a substituent selected from the group consisting of an alkyl group, an alkoxy group, a hydroxy group, a nitro group, a carboxy group, and an acyl group, and one or more substituents may be substituted.
The polysulfonic acid is a sulfonic acid in which a plurality of sulfonic acid groups are substituted on the main chain or side chain of the polymer chain. For example, polystyrene sulfonic acid is mentioned.

The organic acid having one or more carboxy groups is preferably a cyclic, linear or branched alkyl carboxylic acid, substituted or unsubstituted aromatic carboxylic acid, or polycarboxylic acid having one or more carboxy groups.
Examples of the alkyl carboxylic acid include undecylenic acid, cyclohexane carboxylic acid, and 2-ethylhexanoic acid. Here, the alkyl group is preferably a linear or branched alkyl group having 1 to 18 carbon atoms.
Examples of the substituted or unsubstituted aromatic carboxylic acid include substituted or unsubstituted benzene carboxylic acid and naphthalene carboxylic acid. Here, the substituent is, for example, a substituent selected from the group consisting of a sulfonic acid group, an alkyl group, an alkoxy group, a hydroxy group, a nitro group, and an acyl group, and one or more substituents may be substituted. Specific examples include salicylic acid, benzoic acid, naphthoic acid, and trimesic acid.

The organic acid having at least one phosphoric acid group or phosphonic acid group is preferably a cyclic, linear or branched alkylphosphoric acid or alkylphosphonic acid having at least one phosphoric acid group or phosphonic acid group; substituted or unsubstituted aromatic An aromatic phosphoric acid or an aromatic phosphonic acid; a polyphosphoric acid or a polyphosphonic acid.
Examples of the alkyl phosphoric acid or alkylphosphonic acid include dodecyl phosphoric acid and bis (2-ethylhexyl) hydrogen phosphate. Here, the alkyl group is preferably a linear or branched alkyl group having 1 to 18 carbon atoms.
Examples of the aromatic phosphoric acid and aromatic phosphonic acid include substituted or unsubstituted benzene sulfonic acid or phosphonic acid, and naphthalene sulfonic acid or phosphonic acid. Here, the substituent is, for example, a substituent selected from the group consisting of an alkyl group, an alkoxy group, a hydroxy group, a nitro group, a carboxy group, and an acyl group, and one or more substituents may be substituted. An example is phenylphosphonic acid.

The composition forming the shield sheet may contain two or more acidic substances and / or salts of acidic substances that are heat-resistant stabilizers. Specifically, a plurality of different acidic substances and / or salts of different acidic substances may be included.
The content of the heat stabilizer in the composition forming the shield sheet is preferably 0.1% by weight to 3.0% by weight.

(5) Other components The composition forming the electromagnetic wave shielding sheet of the present invention is, for example, 90% by weight or more, 95% by weight or more, 99% by weight or more, and 100% by weight of (1) a π-conjugated conductive material that can be dissolved in a solvent. May comprise a functional polymer, (2) a solvent, (3) a compound having a phenolic hydroxyl group, and (4) a heat-resistant stabilizer, and may further contain additives such as other resins.

Other resin is added as a binder base material, a plasticizer, and a matrix base material, for example.
Specific examples of other resins include, for example, polyolefins such as polyethylene and polypropylene, chlorinated polyolefins, polystyrene, polyester, polyamide, polyacetal, polyethylene terephthalate, polycarbonate, polyethylene glycol, polyethylene oxide, polyacrylic acid, polyacrylic acid ester, Examples thereof include polymethacrylic acid ester and polyvinyl alcohol.
Further, instead of the above resin, together with the resin, a thermosetting resin such as an epoxy resin, a urethane resin, or a phenol resin, or a precursor capable of forming these thermosetting resins may be included.
Furthermore, as other components, components such as carbon fibers such as graphene and carbon nanotubes may be included.

  The manufacturing method of the composition containing the said component is not specifically limited, It can prepare by a well-known method, For example, it can prepare by the method disclosed by WO05 / 052058.

[Other configurations of electromagnetic shielding sheet]
In the electromagnetic wave shielding sheet of the present invention, a protective layer, a pressure-sensitive adhesive layer and the like may be further laminated. For example, a laminate having a three-layer structure of a protective layer / shield layer / adhesive layer can be used.
Examples of the material for the protective layer include polyurethane, polyester, polyamide, acrylic, silicone, fluorine, polyethylene, styrene butadiene, nitrile butadiene, and epoxy synthetic resins. Moreover, the thickness of a protective layer can be 0.5-80 micrometers, for example.
Examples of the material for the adhesive layer include urethane-based hot-melt resins and acrylic-based adhesive resins. Moreover, the thickness of the adhesion layer can be 10-100 micrometers, for example.

[Method of manufacturing electromagnetic shielding sheet]
For example, an electromagnetic wave shielding sheet can be obtained by drying the composition forming the electromagnetic wave shielding sheet and removing the solvent. For example, an electromagnetic wave shielding sheet can be produced by applying a composition for forming a shielding sheet to a substrate such as glass, resin film, sheet or nonwoven fabric having a desired shape and removing the solvent.
By processing the electromagnetic wave shielding sheet into a desired shape by a known method such as vacuum forming or pressure forming, a conductive article can be manufactured. From the viewpoint of molding, the substrate is preferably a resin film, a sheet, or a nonwoven fabric.

As a method for applying the composition to the substrate, known methods such as a casting method, a spray method, a dip coating method, a doctor blade method, a bar coating method, a spin coating method, an electrospinning method, screen printing, and a gravure printing method are used. The casting method is preferable.
When drying the coating film obtained by applying the composition, the coating film may be heated depending on the type of the solvent. For example, it is heated at a temperature of 250 ° C. or lower, preferably 50 or higher and 200 ° C. or lower under an air stream, and further heated under reduced pressure as necessary. The heating temperature and the heating time are not particularly limited and may be appropriately selected depending on the material to be used.

The electromagnetic wave shielding sheet of the present invention is a self-supporting molded article composed only of a shielding sheet having no substrate. The electromagnetic wave shield sheet coated with a conductive polymer such as PEDOT / PSS has a problem of insufficient adhesion to the base material, but the self-supporting electromagnetic wave shield sheet does not cause an adhesion problem.
The electromagnetic wave shielding sheet of the present invention can exhibit desired mechanical strength by appropriately including, for example, the above-described other resin in the composition forming the shielding sheet.

  As described above, the electromagnetic wave shielding sheet of the present invention can be produced as a self-supporting molded article composed only of a shielding sheet having no substrate, and a composition for forming an electromagnetic wave shielding sheet on the surface of an object to be electromagnetic wave shielded. An electromagnetic wave shielding sheet layer may be formed on the object to be shielded by coating using an appropriate technique such as direct spraying.

Example 1
[Production of polyaniline complex]
37.8 g of aerosol OT (sodium di-2-ethylhexylsulfosuccinate) and 1.47 g of sorbon T-20 (manufactured by Toho Chemical Co., Ltd.) which is a nonionic emulsifier having a polyoxyethylene sorbitan fatty acid ester structure are dissolved in 600 mL of toluene. did. The resulting solution was placed in a 6 L separable flask placed under a nitrogen stream, and 22.2 g of aniline was added to this solution. Thereafter, 1800 mL of 1M phosphoric acid was added to the solution, and the temperature of the solution having two liquid phases of toluene and water was cooled to 5 ° C.
When the internal temperature of the solution reached 5 ° C., stirring was performed at 390 rpm. A solution obtained by dissolving 65.7 g of ammonium persulfate in 600 mL of 1M phosphoric acid was dropped using a dropping funnel over 2 hours. The reaction was carried out while maintaining the internal temperature of the solution at 5 ° C. for 18 hours from the start of dropping. Thereafter, the reaction temperature was raised to 40 ° C., and the reaction was continued for 1 hour. Then, it left still and isolate | separated the toluene phase. 1500 ml of toluene is added to the obtained toluene phase, 500 mL of 1M phosphoric acid is washed once with 500 mL of ion-exchanged water, the toluene phase is left to stand, concentrated for concentration adjustment, and a polyaniline complex toluene solution 900 g was obtained. The polyaniline complex concentration of this polyaniline complex toluene solution was 5.7% by weight.
The obtained polyaniline / AOT complex toluene solution was dried under reduced pressure in a 60 ° C. hot water bath and dried to obtain 51.3 g of a polyaniline complex.

[Production and evaluation of electromagnetic shielding sheet]
12 g of the above polyaniline complex was dissolved in a solvent in which 24 g of toluene, 4 g of isopropyl alcohol, 20 g of methyl isobutyl ketone, 19.2 g of 4-methoxyphenol, and 1.1 g of 2-naphthalenesulfonic acid were dissolved to obtain a polyaniline complex solution. .

  The obtained solution was poured into a Teflon-coated container (20 cm × 27 cm) and dried for 1 day on a horizontal table in a nitrogen atmosphere. Thereafter, it was dried at 120 ° C. for 30 minutes to produce an electromagnetic wave shielding sheet.

The thickness of the obtained electromagnetic shielding sheet was measured using a contact-type film thickness meter (Ono Sokki Linear Gauge Sensor GS-3813). The results are shown in Table 1.
Moreover, evaluation of the shielding performance of the obtained electromagnetic wave shielding sheet was implemented using the apparatus shown in FIG. The unit of the numbers in FIG. 1 is “mm”. Using two devices shown in FIG. 1, a measurement sample (shield sheet) was sandwiched between jigs for transmission and reception, and how much the signal was attenuated on the reception side was evaluated by the KEC method. The results are shown in Tables 1 and 2. Table 2 is a graph showing the frequency characteristics of the electromagnetic wave shielding effect.

  The electromagnetic wave shielding sheet of the present invention is excellent in flexibility, and can be suitably used for applications such as electronic equipment housings, gaskets, wall materials, curtains, and blinders.

DESCRIPTION OF SYMBOLS 1 Electric field shielding effect evaluation apparatus 10 Center conductor 20 Outer conductor 30 Input / output

Claims (10)

An electromagnetic wave shielding sheet formed from a composition comprising a compound having a π-conjugated conductive polymer soluble in a solvent and a phenolic hydroxyl group ,
The π-conjugated conductive polymer is a complex of a substituted or unsubstituted polyaniline, which is a complex of a substituted or unsubstituted polyaniline and a sulfosuccinic acid derivative represented by the following formula (III):
Surface resistance 5 [Omega / □ Ri der hereinafter without metal components, electromagnetic wave shielding sheet.

(In the formula, M is a hydrogen atom, an organic free radical or an inorganic free radical, and m ′ is the valence of M.
R ¹³ and R ¹⁴ are each independently a hydrocarbon group or a group represented by — (R ¹⁵ O) _r —R ¹⁶ .
R ¹⁵ is independently a hydrocarbon group or a silylene group, R ¹⁶ is a hydrogen atom, a hydrocarbon group or a group represented by R ¹⁷ ₃ Si—, and r is an integer of 1 or more.
R ¹⁷ is each independently a hydrocarbon group. )   The electromagnetic wave shielding sheet according to claim 1, wherein an electric field component of an electromagnetic wave of 0.15 MHz can be shielded by 40 dB or more. The electromagnetic wave shielding sheet according to claim 1, wherein an electric field component of an electromagnetic wave of 10 MHz can be shielded by 60 dB or more. The electromagnetic wave shielding sheet according to any one of claims 1 to 3, wherein the content of the compound having a phenolic hydroxyl group in the composition is 5 to 60% by weight. The electromagnetic wave shielding sheet according to any one of claims 1 to 4 , wherein the composition contains naphthalenesulfonic acid. Electromagnetic wave shielding sheet according to any one of claims 1 to 5 -containing amount of π-conjugated conductive polymer in the composition is 5-30 wt%. Electromagnetic wave shielding sheet according to any one of claims 1 to 6 thickness is 0.15mm or more. The electromagnetic wave shield sheet according to any one of claims 1 to 7 , formed by a casting method. Including a step of forming an electromagnetic wave shield sheet by a casting method using a composition comprising a π-conjugated conductive polymer soluble in a solvent and a compound having a phenolic hydroxyl group, and having a surface resistance of 5Ω / □ or less, a metal A method for producing an electromagnetic wave shielding sheet containing no components,
In the electromagnetic wave shielding sheet, the π-conjugated conductive polymer is a composite of a substituted or unsubstituted polyaniline, which is a composite of a substituted or unsubstituted polyaniline and a sulfosuccinic acid derivative represented by the following formula (III) : Production method.

(In the formula, M is a hydrogen atom, an organic free radical or an inorganic free radical, and m ′ is the valence of M.
R ¹³ and R ¹⁴ are each independently a hydrocarbon group or a group represented by — (R ¹⁵ O) _r —R ¹⁶ .
R ¹⁵ is independently a hydrocarbon group or a silylene group, R ¹⁶ is a hydrogen atom, a hydrocarbon group or a group represented by R ¹⁷ ₃ Si—, and r is an integer of 1 or more.
R ¹⁷ is each independently a hydrocarbon group. ) A molded article in which an electromagnetic wave shielding sheet layer is formed on the surface by applying a composition containing a compound having a π-conjugated conductive polymer soluble in a solvent and a phenolic hydroxyl group using a spray method ,
The electromagnetic wave shielding sheet layer has a surface resistance of 5Ω / □ or less, does not contain a metal component,
A molded article , wherein the π-conjugated conductive polymer is a composite of a substituted or unsubstituted polyaniline, which is a composite of a substituted or unsubstituted polyaniline and a sulfosuccinic acid derivative represented by the following formula (III) .

(In the formula, M is a hydrogen atom, an organic free radical or an inorganic free radical, and m ′ is the valence of M.
R ¹³ and R ¹⁴ are each independently a hydrocarbon group or a group represented by — (R ¹⁵ O) _r —R ¹⁶ .
R ¹⁵ is independently a hydrocarbon group or a silylene group, R ¹⁶ is a hydrogen atom, a hydrocarbon group or a group represented by R ¹⁷ ₃ Si—, and r is an integer of 1 or more.
R ¹⁷ is each independently a hydrocarbon group. )

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