JP7724627B2 - Gas barrier film materials - Google Patents

Description

The present invention relates to a silicon oxide film that has high gas barrier properties and a high film formation rate even when thin, a gas barrier film material containing a silicon hydride compound that is useful for creating silicon oxide films, and a method for producing silicon oxide films.

Silicon dioxide (silica) is a representative metal oxide material that combines high chemical and thermal stability with favorable physical properties (high strength, transparency, and insulating properties). It is used industrially in a variety of forms, from bulk to nano-sized materials. While wet and dry processes are primarily used to fabricate silicon dioxide thin films, dry processes, particularly chemical vapor deposition (CVD), are primarily used to deposit silicon oxide thin films on substrates because they require fewer steps and produce high-density, highly functional films. In particular, CVD is often used to deposit transparent silicon oxide films on polymeric film materials to impart oxygen and water vapor barrier properties while maintaining their transparency. CVD film formation requires the use of a vaporizable silicon compound as a silicon oxide thin film precursor. Previously, methods have been established for depositing silicon-containing thin films with desired compositions and properties using CVD, using various organosilicon compounds as precursors.

When designing the molecular structure of a silicon oxide thin film precursor for CVD deposition, it is important that it has a high vapor pressure, can be deposited in a plasma atmosphere at a good film-forming rate, and has a molecular structure that allows the silicon oxide thin film to exhibit the desired functions and physical properties. Monosilane compounds with a single silicon atom and alkyl-alkoxy groups are typically used, but there is still significant room for improvement in their film-forming speed. Furthermore, with the trend toward thinner substrates, gas barrier films that exhibit high gas barrier performance at even thinner thicknesses are required. Furthermore, from the perspective of improving productivity, there is a demand for gas barrier film materials with a high film-forming rate that allows for film formation in a short period of time.

Patent Document 1 discloses a method for producing a polyethylene naphthalate (PEN) film with a _SiO2 gas barrier layer formed thereon by a PECVD method using tetraethoxysilane and oxygen as raw materials. Although the water vapor transmission rate (WVTR) of this film is 1.7 × ^10-3 g/ ^m2 ·day, which shows sufficient gas barrier performance, the film formation rate is 67 nm/min, which leaves room for improvement.

Patent Document 2 describes a method for forming a gas barrier film by PECVD using an alkylhydrodisiloxane compound at a film formation rate of 257 nm/min. This gas barrier film is a single layer film with a thickness of 2570 nm, and exhibits a low water vapor transmission rate (WVTR) of 4.0 × 10 ^-3 g/m ² ·day, indicating poor gas barrier properties.

Japanese Patent Application Laid-Open No. 2016-176091 Patent No. 6007662

The object of the present invention is to provide a silicon oxide film that can be formed in a short time, has high gas barrier performance and a high film formation rate, showing a WVTR of the order of 9.0 × 10 ^-3 g/m ² · day or less even at a film thickness of 500 nm or less, a gas barrier film material, and a method for producing a silicon oxide film using the gas barrier film material.

As a result of extensive research to solve the above problems, the inventors discovered that a silicon hydride compound containing two silicon atoms in its molecule, with one hydrogen atom, one alkyl group, and one alkoxy group on the silicon atom, exhibits high vaporization properties, and that it is possible to deposit a silicon oxide thin film on a substrate using plasma-enhanced chemical vapor deposition (hereinafter also referred to as PECVD). They also discovered that the above problems can be solved by using this compound as a gas barrier film material to produce a silicon oxide film, which led to the completion of the present invention.

That is, the present invention comprises the following configurations.
[1]
A silicon oxide film characterized by satisfying the following requirements (1) to (3):
(1) A water vapor transmission rate (WVTR) of 9.0 × 10 ⁻³ g/m ² · day or less at a film thickness of 500 nm or less; (2) A film formation rate of 100 nm/min or more by plasma enhanced chemical vapor deposition; (3) A carbon concentration in the film measured by X-ray photoelectron spectroscopy (XPS) of 3.0 atom% or less [2]
General formula (1)

(1)
(wherein A represents an oxygen atom or a methylene group; R ¹ represents an alkyl group having 1 to 6 carbon atoms; and R ² represents an alkyl group having 1 to 3 carbon atoms),
[3]
The gas barrier film material according to [2], wherein R ¹ is a methyl group, an ethyl group, a propyl group, or an isopropyl group, and R ² is a methyl group, an ethyl group, a propyl group, or an isopropyl group.
[4]
The gas barrier film material is 1,3-dimethyl-1,3-dimethoxydisiloxane, 1,3-dimethyl-1,3-diethoxydisiloxane, 1,3-dimethyl-1,3-di(isopropyloxy)disiloxane, 1,3-diethyl-1,3-dimethoxydisiloxane, 1,3-diethyl-1,3-diethoxydisiloxane, 1,3-diethyl-1,3-di(isopropyloxy)disiloxane, 1,3-diisopropyl The gas barrier film material according to [2] or [3], further comprising at least one selected from the group consisting of 1,3-propyl-1,3-dimethoxydisiloxane, 1,3-diisopropyl-1,3-diethoxydisiloxane, 1,3-diisopropyl-1,3-di(isopropyloxy)disiloxane, bis(methoxymethylsilyl)methane, bis(ethoxymethylsilyl)methane, and bis(isopropylmethoxysilyl)methane.
[5]
[1] A method for producing a silicon oxide film, comprising forming a film from the gas barrier film material according to any one of [2] to [4] by plasma-enhanced chemical vapor deposition under a film-forming pressure of 0.01 Pa or more and less than 50 Pa.
[6]
The method for producing a silicon oxide film according to [5], wherein the film is formed by plasma-enhanced chemical vapor deposition under conditions where the power of a high-frequency power source (RF power source) is 100 W or more.
[7]
The method for producing a silicon oxide film according to [5] or [6], wherein the film is formed by plasma-enhanced chemical vapor deposition under conditions where the power density of a high-frequency power source (RF power source) is ^0.1 W/cm 2 or more.

The present invention is described in detail below.

<Silicon oxide film>
The silicon oxide film of the present invention is characterized by a water vapor transmission rate (WVTR) of 9.0×10 ⁻³ g/m ² ·day or less at a film thickness of 500 nm or less, preferably 50 to 500 nm, more preferably 100 to 500 nm, and particularly preferably 200 to 500 nm, with the WVTR preferably being in the range of 1.0×10 ⁻⁶ to 9.0×10 ⁻³ g/m ² ·day, more preferably 1.0×10 ⁻⁶ to 9.0×10 ⁻⁴ g/m ² ·day, and particularly preferably 1.0×10 ⁻⁴ to 9.0×10 ⁻⁴ g/m ² ·day.

Here, the water vapor transmission rate (WVTR) was measured using gas chromatography (GC).

The silicon oxide film of the present invention has a deposition rate by plasma-enhanced chemical vapor deposition of 100 nm/min or more, preferably 100 to 1000 nm/min, more preferably 100 to 500 nm/min, 100 to 300 nm/min, and particularly preferably 100 to 200 nm/min.

Here, the film formation rate was determined from the film thickness and film formation time obtained by photographing a cross-sectional image of the film using a field emission scanning electron microscope (FE-SEM, manufactured by JEOL Ltd.) JSM-7600F.

The silicon oxide film of the present invention is also characterized by a carbon concentration in the film measured by X-ray photoelectron spectroscopy (XPS) of 3.0 atom% or less, preferably 1.5 atom% or less, and more preferably 1.0 atom% or less. A lower carbon concentration in the film is preferable because it has higher transmittance to visible light and a lower WVTR.

Furthermore, the thickness of the silicon oxide film is preferably 10 nm or more to achieve high gas barrier performance, more preferably a thickness selected appropriately from the range of 50 nm to 1000 nm, and even more preferably a thickness selected appropriately from the range of 100 nm to 1000 nm.

In this invention, the gas barrier performance of a silicon oxide film refers to its impermeability to gases such as oxygen, nitrogen, carbon dioxide, and water vapor. Furthermore, the gas barrier performance is evaluated using the water vapor transmission rate (WVTR), as this is commonly used as a measurement and evaluation index by those skilled in the materials field.

The silicon oxide film of the present invention can also be a laminated film consisting of a silicon oxide layer and a substrate.

Substrates include, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), cycloolefin polymer (COP), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), polyethersulfone (PES), cycloolefin copolymer (COC), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymer (EVOH), ABS resin, methacrylic resin, epoxy resin, modified polyphenylene ether, poly Examples of suitable resins include acetal, polybutylene terephthalate, polyacrylate, polyarylate, polysulfone, polyamideimide, polyetherimide, polyphenylene sulfide, polyetheretherketone, and fluororesin. Of these, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), cycloolefin polymer (COP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), polyethersulfone (PES), methacrylic resin, and epoxy resin are preferred. Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), and cycloolefin polymer (COP) are particularly preferred.

The laminated film preferably has a visible light transmittance of 80% or more, more preferably 84% or more, and even more preferably 86% or more.

Here, visible light transmittance is the average transmittance (including the substrate) at wavelengths of 380 to 780 nm measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation). The average transmittance of the substrate is also a measurement value using the same device.

There are no particular restrictions on the thickness of the laminated film (total thickness of the silicon oxide film and substrate), but it is preferably 10 μm or more, more preferably 50 μm to 2000 μm, and even more preferably 100 μm to 1000 μm. The preferred thickness of the silicon oxide film in the laminated film is as described above.

<Gas barrier film materials>
Next, the gas barrier film material will be described.

The gas barrier film material of the present invention is a gas barrier film material for chemical vapor deposition, containing a silicon hydride compound (1) represented by the following general formula (1):

(1)
(In the formula, A represents an oxygen atom or a methylene group, ^R1 represents an alkyl group having 1 to 6 carbon atoms, and ^R2 represents an alkyl group having 1 to 3 carbon atoms.)
First, A, ^R1 and ^R2 in general formula (1) will be explained.

A is a linker moiety that connects two silicon atoms and is an oxygen atom or a methylene group. An oxygen atom is preferred because it provides excellent evaporation characteristics.

^R1 is an alkyl group having 1 to 6 carbon atoms, and may be linear, branched, or cyclic. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, pentyl, cyclopentyl, 1-methylbutyl, 2-ethylpropyl, neopentyl, hexyl, 1-methylpentyl, 2-ethylbutyl, and cyclohexyl. Of these, from the standpoints of the cost of the silicon hydride compound, high vapor pressure, and the gas barrier performance of the formed silicon oxide film, methyl, ethyl, propyl, or isopropyl is preferred, methyl, ethyl, or isopropyl is more preferred, and methyl or isopropyl is particularly preferred.

^R2 is an alkyl group having 1 to 3 carbon atoms, and may be linear, branched, or cyclic. Examples of such alkyl groups include methyl, ethyl, propyl, isopropyl, and cyclopropyl. Of these, from the viewpoints of production costs of the silicon hydride compound, high vapor pressure, and the water vapor barrier properties of the formed silicon oxide film, methyl, ethyl, propyl, or isopropyl is preferred, methyl, ethyl, or isopropyl is more preferred, and methyl or isopropyl is particularly preferred.

The silicon hydride compound (1) in general formula (1) can occur in three isomers: the (1R,3R) isomer, the (1R,3S) isomer, and the (1S,3S) isomer, depending on the stereochemistry of the two silicon atoms. The (1R,3R) isomer and the (1S,3S) isomer are enantiomers of each other. The silicon hydride compound (1) may be a mixture of these isomers, or may contain one of them predominantly.

Examples of silicon hydride compounds represented by general formula (1) include the following compounds. Note that, throughout this specification, Me, Et, Pr, i-Pr, Bu, i-Bu, sec-Bu, and tert-Bu represent methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl groups, respectively.

Of these, 1,3-dimethyl-1,3-dimethoxydisiloxane (1-1-1), 1,3-dimethyl-1,3-diethoxydisiloxane (1-1-2), 1,3-dimethyl-1,3-di(isopropyloxy)disiloxane (1-1-4), 1,3-diethyl-1,3-dimethoxydisiloxane (1-2-1), 1,3-diethyl-1,3-diethoxydisiloxane (1-2-2), and 1,3-diethyl-1,3-diethoxydisiloxane (1-2-3) are preferred due to their high vapor pressure, the high barrier properties of the silicon oxide film after deposition, and their economical efficiency. 2), 1,3-diethyl-1,3-di(isopropyloxy)disiloxane (1-2-4), 1,3-diisopropyl-1,3-dimethoxydisiloxane (1-4-1), 1,3-diisopropyl-1,3-diethoxydisiloxane (1-4-2), 1,3-diisopropyl-1,3-di(isopropyloxy)disiloxane (1-4-4), bis(methoxymethylsilyl)methane (1-14-1), bis(ethoxymethylsilyl)methane (1-14-2) or bis (Isopropylmethoxysilyl)methane (1-17-1) is preferred, and 1,3-dimethyl-1,3-dimethoxydisiloxane (1-1-1), 1,3-dimethyl-1,3-di(isopropyloxy)disiloxane (1-1-4), 1,3-diisopropyl-1,3-dimethoxydisiloxane (1-4-1), 1,3-diisopropyl-1,3-diethoxydisiloxane (1-4-2), 1,3-diisopropyl-1,3-di(isopropyloxy)disiloxane (1 1-4-4), bis(methoxymethylsilyl)methane (1-14-1), or bis(isopropylmethoxysilyl)methane (1-17-1) are more preferred, and 1,3-dimethyl-1,3-dimethoxydisiloxane (1-1-1), 1,3-dimethyl-1,3-di(isopropyloxy)disiloxane (1-1-4), 1,3-diisopropyl-1,3-dimethoxydisiloxane (1-4-1), or bis(methoxymethylsilyl)methane (1-14-1) are especially preferred.

Silicon hydride compound (1) can be obtained commercially or synthesized using known production methods. These synthesis methods include hydrolysis of functional silanes (Synthesis Examples 1 and 2) or alkoxylation of 1,3-dihalo-1,3-dialkyldisiloxane when A in general formula (1) is an oxygen atom, and alkoxylation of bis(chloroalkylsilyl)methane (Synthesis Example 3) when A in general formula (1) is a methylene group. These methods are easily accomplished by those skilled in the art. The synthesized organosilane compound can also be purified using commonly used methods such as concentration, distillation, and column chromatography before use in film formation.

These silicon hydride compounds (1) may be used alone as gas barrier film materials, or multiple types may be mixed in any ratio and used as gas barrier film materials. They may also contain another organosilicon compound capable of producing a silicon oxide film. Examples of such organosilicon compounds include tetramethoxysilane, tetraethoxysilane, hexamethoxydisiloxane, and hexamethyldisiloxane.

<Method for producing silicon oxide film>
Next, the method for producing a silicon oxide film of the present invention will be described.

The silicon oxide film of the present invention is produced by depositing the above-mentioned gas barrier film material under a deposition pressure of 0.01 Pa or more and less than 50 Pa by plasma-excited chemical vapor deposition.

In addition, the silicon oxide film manufacturing method involves producing a silicon oxide film on a substrate as described below, and therefore can also produce a laminated film at the same time.

In the method for producing a silicon oxide film of the present invention, deposition is performed by plasma-enhanced chemical vapor deposition (PECVD), during which oxygen must be supplied in addition to the silicon hydride compound (1). Specifically, when producing a silicon oxide film using the silicon hydride compound (1) and oxygen as raw materials by PECVD, the silicon hydride compound (1) is vaporized and supplied to a deposition chamber containing a substrate for deposition. Vaporization methods that can be used include, for example, placing a container containing the silicon hydride compound (1) in a heated thermostatic chamber and reducing the pressure using a vacuum pump or the like; placing a container containing the silicon hydride compound (1) in a heated thermostatic chamber and blowing in a carrier gas such as helium, neon, argon, krypton, xenon, or nitrogen; or sending the silicon hydride compound (1) directly or in solution to a vaporizer, heating it, and vaporizing it in the vaporizer (liquid injection method).

Examples of solvents that can be used to prepare a solution include ethers such as 1,2-dimethoxyethane, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), 1,4-dioxane, tetrahydrofuran, and cyclopentyl methyl ether, and hydrocarbons such as hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, octane, nonane, decane, benzene, toluene, ethylbenzene, and xylene. As the solvent, one of these may be used alone, or two or more may be mixed in any ratio.

The silicon hydride compound (1) and oxygen supplied to the film formation chamber in this manner react with the plasma generated in the film formation chamber, forming a silicon oxide film on the film formation substrate. Film formation can proceed using plasma alone, but light irradiation or heating of the film formation substrate may also be used in combination.

There are no particular limitations on the plasma generation source, and examples include capacitively coupled plasma, inductively coupled plasma, helicon wave plasma, surface wave plasma, and electron cyclotron resonance plasma.

The film-forming equipment used to produce silicon oxide films can be any chemical vapor deposition equipment commonly used by those skilled in the art, and substrate transport methods include, for example, batch, single-wafer, and roll-to-roll methods.

The film formation pressure must be in the range of 0.01 Pa or more and less than 50 Pa, and it is preferable that the pressure be appropriately selected from the range of 0.1 Pa or more and 40 Pa or less, in order to ensure a low WVTR of the resulting silicon oxide film and to facilitate control of the degree of vacuum.

The power of the radio frequency power source (RF power source) is preferably 100 W or more, more preferably 200 W to 1500 W, and even more preferably 700 W to 1500 W, as this results in a low WVTR of the resulting silicon oxide film.

The density of the power applied to the electrodes for plasma discharge is preferably 0.1 W/cm ² or more, more preferably 2.0 W/cm ² to 100 W/cm ² in view of the low WVTR of the resulting silicon oxide film.

There are no particular restrictions on the temperature of the film-forming substrate during film formation, but it is preferable that the temperature be below the heat-resistant temperature of the film-forming substrate and be appropriately selected from the range of 0°C to 300°C.

There are no particular limitations on the type of substrate material used for film formation, and examples include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), cycloolefin polymer (COP), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), polyethersulfone (PES), cycloolefin copolymer (COC), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymer (EVOH), ABS resin, methacrylic resin, epoxy resin, modified polyphenylene ether, polyacetal, polybutylene terephthalate, polyacrylate, polyarylate, polysulfone, polyamideimide, polyetherimide, polyphenylene sulfide, polyether ether ketone, fluororesin, etc. Of these, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), cycloolefin polymer (COP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), polyethersulfone (PES), methacrylic resin, or epoxy resin is preferred. Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyamide (PA), polyimide (PI), or cycloolefin polymer (COP) is even more preferred.

When the supply flow rate of silicon hydride compound (1) during film formation is X and the supply flow rate of oxygen is Y, the flow rate ratio of oxygen to silicon hydride compound (1) (Y/X) is preferably 1 or greater, and a flow rate ratio appropriately selected from the range of 5 to 100 is even more preferable.

By using a gas barrier film material for chemical vapor deposition containing the silicon hydride compound (1) of the present invention as a CVD precursor, a transparent silicon oxide film exhibiting extremely high oxygen and water vapor barrier properties can be applied to the treated substrate in a short period of time. This is particularly suitable for improving the oxygen and water vapor barrier properties of organic polymer film substrates.

Because the silicon oxide film of the present invention exhibits high gas barrier properties, it can be suitably used as a packaging material for food products, packaging material for electronic devices, and as an encapsulation film for electronic devices such as solar cells and EL devices. Furthermore, as a thin, high-strength silicon oxide film, it is believed that thin-film processing with improved thermal, chemical, and mechanical properties will be possible for the surfaces of various types of substrates.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the scope of the present invention should not be construed as being limited by the specific examples shown below.

A silicon oxide film was deposited on a substrate using a standard CVD apparatus for film deposition using the capacitively coupled PECVD method. A 125 μm-thick polyethylene naphthalate (PEN) film (visible light transmittance 88.3%) was used as the substrate. The source gases used were silicon hydride compound (1), oxygen gas, and argon gas vaporized in a thermostatic chamber. Furthermore, a high-frequency power source with a frequency of 13.56 MHz was used as the power source.

The thickness of the deposited silicon oxide film was roughly estimated by photographing a cross-sectional image of the silicon oxide film using a field emission scanning electron microscope (FE-SEM, manufactured by JEOL Ltd.) JSM-7600F.

Water vapor transmission rate (WVTR), an indicator of gas barrier performance, was measured by gas chromatography (GC) using a moisture transmission rate measuring device (GTR Tech, GTR3000 series).

The film composition (including carbon concentration) of the silicon oxide film was analyzed using an X-ray photoelectron spectrometer (ULVAC-PHI, XPS) PHI5000 VersaProbe II.

The synthesized silicon hydride compound (1) was analyzed by ¹ H-NMR (proton nuclear magnetic resonance spectroscopy), ¹³ C-NMR (carbon-13 nuclear magnetic resonance spectroscopy), and ²⁹ Si-NMR (silicon-29 nuclear magnetic resonance spectroscopy) using a Bruker-Avance DPX-400 nuclear magnetic resonance spectrometer, with deuterated chloroform as the measurement solvent. IR (infrared absorption) spectroscopy was performed using a Horiba FT-720 spectrophotometer and a SensIR technologies DuraSamplIRII (reflection type). Mass spectroscopy was performed using a gas chromatography mass spectrometer (Shimadzu Corporation, GCMS-QP2010 model), with an Agilent Technologies DB-5MS capillary column.

The following substances used in the preparation were commercially available and used as they were: trichlorosilane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), dichloroethylsilane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), dichloromethylsilane (Sigma-Aldrich Japan K.K.), 2-chloropropane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), dibromomethane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), dibromoethane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), magnesium metal (reagent manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), dehydrated diethyl ether (reagent manufactured by Kanto Chemical Co., Ltd.), dehydrated tetrahydrofuran (hereafter abbreviated as THF) (reagent manufactured by Kanto Chemical Co., Ltd.), dehydrated hexane (reagent manufactured by Kanto Chemical Co., Ltd.), dehydrated methanol (reagent manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), dehydrated ethanol (reagent manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), pyridine (reagent manufactured by Kanto Chemical Co., Ltd.), quinoline (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), diethylamine (reagent manufactured by Kanto Chemical Co., Ltd.), and triethylamine (reagent manufactured by Kanto Chemical Co., Ltd.).

(Synthesis Example 1) Synthesis of 1,3-diethyl-1,3-dimethoxydisiloxane (compound (1-2-1))

<Preparation of chloro(diethylamino)ethylsilane>
A 300 mL three-neck flask equipped with a magnetic stir bar, dropping funnel, Dimroth condenser, and three-way stopcock was purged with argon and charged with 12.1 g (93.8 mmol) of dichloroethylsilane and 160 mL of THF. 25.1 g (0.194 mol) of quinoline and 6.85 g (93.6 mmol) of diethylamine were added to the dropping funnel. The reaction vessel was cooled to 0°C and the mixture was added dropwise over 1 hour, followed by stirring for 1.5 hours.
<Preparation of ethyl(diethylamino)methoxysilane>
10 mL of THF and 3.06 g (95.6 mmol) of methanol were placed in the dropping funnel and added dropwise over 40 minutes while the reaction vessel was cooled to 0° C. After the dropwise addition was completed, the temperature was returned to room temperature and the mixture was stirred for 4 hours.
<Synthesis of 1,3-diethyl-1,3-dimethoxydisiloxane>
To the reaction mixture, 0.856 g (47.5 mmol) of distilled water was added via syringe over 5 minutes, and the mixture was stirred for 22 hours. The mixture was filtered using a Schlenk tube equipped with a filter and lined with Celite under an argon atmosphere, and the resulting liquid was concentrated. This was distilled under reduced pressure to obtain 2.69 g (yield 29.5%) of 1,3-diethyl-1,3-dimethoxydisiloxane (compound (1-2-1)) (boiling point 83°C/7.3 kPa) as a colorless liquid.
Mass spectrum (electron impact ionization, 70 eV), m/z (%): 193 ([MH] ⁺ , 2), 165 ([M-Et] ⁺ , 100), 135 (74); ¹ H-NMR (400 MHz, CDCl ₃ ) δ (ppm): 0.643 (q, 4H, J = 7.8Hz), 0.99 (t, 6H, J = 7.9Hz), 3.56 (s, 6H), 4.55 (t, 2H, J = 1.3Hz); ^13C -NMR (101MHz, CDCl ₃ ) δ (ppm): 5.325, 6.822, 51.03; ²⁹ Si-NMR (79 MHz, CDCl ₃ ) δ (ppm): -21.78; Infrared spectrum (neat, cm ^-1 ): 2960, 2939, 2918, 2893, 2879, 2837, 2135, 1460, 1414, 1381, 1240, 1190, 1086, 1065, 1009, 966, 829, 771, 704.

(Synthesis Example 2) Synthesis of 1,3-diisopropyl-1,3-dimethoxydisiloxane (compound (1-4-1))

<Preparation of dichloroisopropylsilane>
9.40 g (387 mmol) of magnesium metal turnings were placed in a 500 mL three-neck flask equipped with a magnetic stirrer, a dropping funnel, a Dimroth condenser, and a three-way stopcock, and the atmosphere inside the flask was replaced with argon. 10 mL of anhydrous THF was placed in the three-neck flask, and 0.1 mL of 1,2-dibromoethane was added to activate the magnesium. Next, a solution of 29.9 g (381 mmol) of 2-chloropropane in 190 mL of anhydrous THF was added dropwise from the dropping funnel over 1.5 hours, and after the dropwise addition, the mixture was stirred at room temperature for an additional 1.5 hours to prepare an isopropyl magnesium chloride solution.

Separately, a 1000 mL three-neck flask equipped with a magnetic stirrer, a dropping funnel, a Dimroth condenser, and a three-way stopcock was purged with argon, and 50.9 g (376 mmol) of trichlorosilane and 300 mL of dehydrated THF were placed in the reaction vessel. The reaction vessel was cooled to -10°C, and the previously prepared isopropyl magnesium chloride solution was added dropwise from the dropping funnel over 4.5 hours. After the dropwise addition was completed, the reaction vessel was returned to room temperature and stirred for 72 hours to prepare a solution containing isopropyldichlorosilane.
<Preparation of (diethylamino)isopropylmethoxysilane>
The above solution containing isopropyldichlorosilane was cooled to 0°C, and a mixture of 77.5 g (0.765 mol) of triethylamine and 27.1 g (0.376 mol) of diethylamine was added dropwise from the dropping funnel over 1 hour, followed by stirring for an additional 2 hours. Furthermore, a solution of 12.1 g (0.376 mol) of methanol in 40 mL of dehydrated THF was added dropwise to this mixture from the dropping funnel over 2 hours at 0°C. After the addition was completed, the mixture was stirred at room temperature for 16 hours to prepare a solution of (diethylamino)isopropylmethoxysilane.
<Synthesis of 1,3-diisopropyl-1,3-dimethoxydisiloxane>
3.99 g (0.188 mol) of distilled water was slowly added via syringe to the three-neck flask containing the reaction mixture while stirring, and the mixture was then heated to reflux for 2 hours. The solution was concentrated to approximately half its original volume under reduced pressure, to which 300 mL of dehydrated hexane was added, and the solids were filtered out using a sintered glass filter under an argon atmosphere. The concentration, hexane dilution, and filtration procedures were repeated once more. After concentration, the crude product was distilled under reduced pressure (boiling point 86°C/4.8 kPa) to obtain 22.6 g (yield 54%) of 1,3-diisopropyl-1,3-dimethoxydisiloxane (compound (1-4-1)) as a colorless liquid.

This compound contains isomers with the stereochemistry at the silicon atom being (1R,3R), (1S,3S), and (1R,3S). The former two and the latter are diastereomers, so two very close signals were observed in silicon NMR.
Mass spectrum (electron impact ionization, 70 eV), m/z (%): 179 ([M-Pr] ⁺ , 100), 151 (72), 121 (65); ¹ H-NMR (400 MHz, CDCl ₃ ) δ (ppm): 0.842 to 0.932 (m, 2H), 1.01 (dd, 12H, J = 7.12, 1.32Hz), 3.57 (s, 6H), 4.44 (d, 2H, J = 0.68Hz); ^13C -NMR (101MHz, CDCl ₃ ) δ (ppm): 13.49, 15.67, 51.28; ²⁹ Si-NMR (79 MHz, CDCl ₃ ) δ (ppm): -21.90, -21.87; Infrared spectrum (neat, cm ^-1 ): 2945, 2897, 2868, 2837, 2131, 1464, 1385, 1246, 1190, 1165, 1088, 1057, 1001, 922, 881, 825, 766, 683, 661, 648.

(Synthesis Example 3) Synthesis of bis(ethoxymethylsilyl)methane (compound (1-14-2)) <Preparation of bis(chloromethylsilyl)methane>

A 300 mL three-neck flask equipped with a Dimroth condenser and a three-way stopcock was charged with a magnetic stirrer and 10.0 g (0.412 mmol) of magnesium metal turnings, and the atmosphere was purged with argon. This vessel was charged with 10 mL of THF, 1.00 g of dibromomethane, and 80.1 g (0.696 mol) of methyldichlorosilane. A dropping funnel was charged with 170 mL of THF and 29.0 g (0.173 mmol) of dibromomethane, and the mixture was added dropwise over 7.5 hours. After reacting at room temperature for one day, the mixture was filtered under an argon atmosphere using a Schlenk flask equipped with a glass filter and lined with Celite. The solvent was removed under reduced pressure, and 15.5 g (51.9% yield) of bis(chloromethylsilyl)methane was obtained by vacuum distillation (106 °C/35.1 kPa).
<Synthesis of bis(ethoxymethylsilyl)methane>

A 300 mL three-neck flask equipped with a magnetic stir bar, Dimroth condenser, and three-way stopcock was purged with argon. 100 mL of diethyl ether and 23.5 g (0.136 mol) of bis(chloromethylsilyl)methane were placed in the vessel. The reaction vessel was cooled to 0°C, and a mixture of 30 mL of diethyl ether, 23.7 g (0.300 mol) of pyridine, and 19.0 g (0.412 mol) of dehydrated ethanol was added dropwise from the dropping funnel over 1.5 hours. The mixture was stirred at room temperature for one day and then filtered under an argon atmosphere using a Schlenk flask equipped with a glass filter and lined with Celite. The solvent was removed under reduced pressure, and 14.2 g (yield 54.3%) of bis(ethoxymethylsilyl)methane (compound (1-14-2)) was obtained by vacuum distillation (82°C/6.5 kPa).
Mass spectrum (electron impact ionization, 70 eV), m/z (%): 191 ([MH] ⁺ , 40), 177 ([M-CH ₃ ] ⁺ , 70), 163 ([M-CH ₂ CH ₃ ] ⁺ , 12), 147 ([M-OCH ₂ CH ₃ ] ⁺ , 47), 119 (100); ¹ H-NMR (400 MHz, CDCl ₃ ) δ (ppm): 0.15-0.21 (m, 2H), 0.26 (d, 6H, J = 2.80Hz), 1.21 (t, 6H, J = 7.00Hz), 3.71 (qd, 4H, J = 6.97, 0.64Hz), 4.64-4.69 (m, 2H); ¹³ C-NMR (101 MHz, CDCl ₃ ) δ (ppm): -1.023, -0.928, 2.639, 18.19, 59.76; ²⁹ Si-NMR (79 MHz, CDCl ₃ ) δ (ppm): 2.746, 2.763; infrared spectrum (neat, cm ⁻¹ ): 2972, 2925, 2891, 2871, 2106, 1481, 1442, 1390, 1352, 1292, 1254, 1165, 1105, 1076, 1041, 997, 945, 887, 866, 849, 764.

Example 1 Film Formation Using 1,3-Diethyl-1,3-Dimethoxydisiloxane (Compound (1-2-1)) A silicon oxide film was formed on a PEN film by PECVD using 1,3-diethyl-1,3-dimethoxydisiloxane (Compound (1-2-1)) together with oxygen. The film formation was carried out for 3 minutes under the following conditions: the supply flow rate of 1,3-diethyl-1,3-dimethoxydisiloxane (Compound (1-2-1)) was 18 sccm, the oxygen supply flow rate was 180 sccm, the film formation chamber pressure was 40 Pa, and the power of the high-frequency power supply (RF power supply) with a power frequency of 13.56 MHz was 900 W. The ratio (Y/X) of the supply flow rate of oxygen to the supply flow rate of 1,3-diethyl-1,3-dimethoxydisiloxane (Compound (1-2-1)) was 10.0.

The thickness of the obtained silicon oxide film was 324 nm. The film formation rate was 108 nm/min. The film composition was Si=33 atom %, O=67 atom %, and the carbon concentration was less than 1.0 atom %. The WVTR was 3.9×10 ⁻⁴ g/m ² ·day.

The visible light transmittance of the laminated film consisting of a silicon oxide film and a PEN film was 87.7%.

When 1,3-diethyl-1,3-dimethoxydisiloxane (compound (1-2-1)) was used together with oxygen to form a film by PECVD, even a thin silicon oxide film with a thickness of 300 nm exhibited high gas barrier performance with a WVTR on the order of 10 ⁻⁴ g/m ² ·day, and the film formation rate was also high at 100 nm/min or more, making it suitable as a gas barrier film.

Example 2 Film Formation Using 1,3-Diisopropyl-1,3-Dimethoxydisiloxane (Compound (1-4-1)) A silicon oxide film was formed on a PEN film by PECVD using 1,3-diisopropyl-1,3-dimethoxydisiloxane (Compound (1-4-1)) together with oxygen. The film formation was carried out for 2 minutes under the following conditions: the supply flow rate of 1,3-diisopropyl-1,3-dimethoxydisiloxane (Compound (1-4-1)) was 13 sccm, the oxygen supply flow rate was 90 sccm, the film formation chamber pressure was 40 Pa, and the power of the high-frequency power supply (RF power supply) with a power frequency of 13.56 MHz was 900 W. The ratio (Y/X) of the supply flow rate of oxygen to the supply flow rate of 1,3-diisopropyl-1,3-dimethoxydisiloxane (Compound (1-4-1)) was 6.9.

The thickness of the obtained silicon oxide film was 306 nm. The film formation rate was 153 nm/min. The film composition was Si=33 atom %, O=67 atom %, and the carbon concentration was less than 1.0 atom %. The WVTR was 6.4×10 ⁻³ g/m ² ·day.

The visible light transmittance of the laminated film consisting of a silicon oxide film and a PEN film was 86.8%.

When 1,3-diisopropyl-1,3-dimethoxydisiloxane (compound (1-4-1)) was used together with oxygen to form a film by PECVD, even a thin silicon oxide film with a thickness of 300 nm exhibited high gas barrier performance with a WVTR on the order of ^{10 g} /m day, and the film formation rate was also high at 100 nm/min or more, making it suitable as a gas barrier film.

Example 3: Film formation using bis(ethoxymethylsilyl)methane (compound (1-14-2)) Using bis(ethoxymethylsilyl)methane together with oxygen, a silicon oxide film was formed on a PEN film by PECVD. The bis(ethoxymethylsilyl)methane supply flow rate was 16 sccm, the oxygen supply flow rate was 90 sccm, the film formation chamber pressure was 40 Pa, and the power of the high-frequency power supply (RF power supply) with a power frequency of 13.56 MHz was 900 W, and film formation was carried out for 2 minutes. The ratio of the oxygen supply flow rate to the bis(ethoxymethylsilyl)methane supply flow rate (Y/X) was 5.6.

The thickness of the obtained silicon oxide film was 290 nm. The film formation rate was 145 nm/min. The film composition was Si=35 atom %, O=65 atom %, and the carbon concentration was less than 1.0 atom %. The WVTR was 4.4×10 ⁻³ g/m ² ·day.

The visible light transmittance of the laminated film consisting of a silicon oxide film and a PEN film was 86.4%.

When bis(ethoxymethylsilyl)methane is used together with oxygen to form a film by the PECVD method, even a thin silicon oxide film with a thickness of 290 nm exhibits high gas barrier performance with a WVTR on the order of 10 ⁻³ g/m ² ·day, and the film formation rate is high at 100 nm/min or more, making it suitable as a gas barrier film.

Comparative Example 1: Film formation using tert-butyltriethoxysilane. Tert-butyltriethoxysilane was synthesized with reference to the method described in K. Lin, R. J. Wiles, C. B. Kelly, G. H. M. Davies, and G. A. Molander, ACS Catalysis, 2017, Vol. 7, pp. 5129-5133. Using tert-butyltriethoxysilane, together with oxygen, a silicon oxide film was formed on a PEN film by PECVD. The film formation was performed for 14 minutes with the tert-butyltriethoxysilane supply flow rate set to 80 sccm, the oxygen supply flow rate set to 2100 sccm, the film formation chamber pressure set to 8 Pa, and the power of a high-frequency power source (RF power source) with a power frequency of 13.56 MHz set to 1000 W. The ratio Y/X of the supply flow rate of oxygen to the supply flow rate of tert-butyltriethoxysilane was 26.3.

The resulting silicon oxide film had a thickness of 800 nm. The film had a composition of Si=33 atom %, O=67 atom %, and a carbon concentration of less than 1.0 atom %. The WVTR value was 2.0×10 ⁻⁴ g/m ² ·day.

The visible light transmittance of the laminated film consisting of a silicon oxide film and a PEN film was 88.2%.

A silicon oxide film was deposited on a PEN film using PECVD with tert-butyltriethoxysilane and oxygen. The tert-butyltriethoxysilane supply flow rate was 80 sccm, the oxygen supply flow rate was 2100 sccm, the deposition chamber pressure was 8 Pa, and the power of the radio frequency power supply (RF power supply) with a power frequency of 13.56 MHz was 1000 W. Deposition was carried out for 7 minutes. The ratio of the oxygen supply flow rate to the tert-butyltriethoxysilane supply flow rate, Y/X, was 26.3.

The thickness of the obtained silicon oxide film was 400 nm. The film formation rate was 57 nm/min. The WVTR value was 4.3×10 ⁻⁴ g/m ² ·day. The visible light transmittance of the laminated film consisting of the silicon oxide film and the PEN film was 88.5%.

When a film is formed by PECVD using tert-butyltriethoxysilane together with oxygen, even a thin silicon oxide film with a thickness of 400 nm exhibits a WVTR of the order of 10 ⁻⁴ g/m ² ·day, which is less than 10 ⁻³ g/m ² ·day, but the film formation rate is low at 57 nm/min, resulting in poor productivity.

Comparative Example 2: Film formation using hexamethyldisiloxane. Hexamethyldisiloxane was used together with oxygen to form a film on a PEN film by PECVD. The hexamethyldisiloxane supply flow rate was 80 sccm, the oxygen supply flow rate was 2100 sccm, the pressure in the film formation chamber was 6 Pa, and the power of the high-frequency power source (RF power source) with a power frequency of 13.56 MHz was 1000 W. Film formation was performed for 2 minutes. The ratio of the oxygen supply flow rate to the hexamethyldisiloxane supply flow rate, Y/X, was 26.3.

The film obtained had a thickness of 200 nm, a film formation rate of 117 nm/min, and a high WVTR of 2.4×10 ⁻² g/m ² ·day.

When a film was formed by PECVD using hexamethyldisiloxane together with oxygen, the film formation rate was high at 117 nm/min for a thin silicon oxide film with a thickness of 200 nm, but the WVTR was high at 2.4×10 ⁻² g/m ² ·day.

Claims (3)

General formula (1)
(1)
(wherein A represents an oxygen atom or a methylene group; R ¹ represents an alkyl group having 1 to 6 carbon atoms; and R ² represents an alkyl group having 1 to 3 carbon atoms), 2. The gas barrier film material according to claim 1 , wherein ^R1 is a methyl group, an ethyl group, a propyl group, or an isopropyl group, and ^R2 is a methyl group, an ethyl group, a propyl group, or an isopropyl group. The gas barrier film material is 1,3-dimethyl-1,3-dimethoxydisiloxane, 1,3-dimethyl-1,3-diethoxydisiloxane, 1,3-dimethyl-1,3-di(isopropyloxy)disiloxane, 1,3-diethyl-1,3-dimethoxydisiloxane, 1,3-diethyl-1,3-diethoxydisiloxane, 1,3-diethyl-1,3-di(isopropyloxy)disiloxane, 1,3-diisopropyl 3. The gas barrier film material according to claim 1, comprising one or more compounds selected from the group consisting of 1,3- diisopropyl-1,3-dimethoxydisiloxane, 1,3-diisopropyl-1,3-diethoxydisiloxane, 1,3-diisopropyl-1,3-di(isopropyloxy)disiloxane, bis(methoxymethylsilyl)methane, bis(ethoxymethylsilyl)methane, and bis (isopropylmethoxysilyl)methane.