JPWO2015005421A1 - Method for producing moisture-proof substrate, moisture-proof substrate, polarizing plate using the moisture-proof substrate, and liquid crystal display panel - Google Patents

Abstract

Provided is a method for producing a moisture-proof substrate that has sufficient moisture-proof properties even if it is thin, and that can significantly suppress warpage and deformation caused by a hygroscopic substrate. The method for producing a moisture-proof substrate according to the invention comprises a moisture-absorbing substrate having a water absorption rate of 1% or more and a moisture-proof film formed on at least one surface side of the moisture-absorbing substrate. A silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less on at least one surface side of the hygroscopic substrate. Including forming a moisture-proof film having a film thickness of 30 nm or more by a plasma chemical vapor deposition method.

Description

  The present invention relates to a moisture-proof substrate that is used as, for example, a packaging material or a substrate material for electronic devices or the like and hardly generates a warp having a very low moisture permeability.

  Various devices such as optical devices, display devices such as liquid crystal display panels and organic EL (Electro-Luminescence) display panels, semiconductor devices, and solar cell modules have many parts and parts that require moisture resistance. For example, a polarizing plate used in a liquid crystal display panel is known to have problems such as a change in polarization characteristics due to humidity.

  For these problems, by attaching a resin film with a metal or inorganic compound thin film on the surface as a moisture-proof substrate, it is possible to give moisture-proof properties to parts and parts that require moisture resistance. It has been known. For example, it is known to attach a moisture-proof substrate as described above to a polarizing plate to impart moisture resistance.

  In addition, with respect to the problem that the optical properties of the polarizing plate are deteriorated or discolored due to the interaction between heat and humidity, Japanese Patent Application Laid-Open No. 03-148603 (hereinafter referred to as Patent Document 1) has a transparent layer having a moisture-proof layer. It has been proposed to provide a protective layer on one or both sides of the polarizing film. Patent Document 1 describes that a polyester-based resin, a polyether sulfone-based resin, a polycarbonate-based resin, a polyamide-based resin, a polyimide-based resin, an acrylic resin, and an acetate-based resin can be used as the transparent protective layer forming material. In addition, vacuum deposition is performed using a compound such as silicon oxide, indium oxide, tin oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium fluoride, and zinc oxide on at least one surface side of the transparent protective layer. It describes that a moisture-proof layer is formed by a method, a sputtering method, or an ion plating method.

In JP-A-2001-235625 (hereinafter referred to as Patent Document 2), in a polarizing plate provided with a triacetyl cellulose (TAC) film as a protective layer, the thickness of the protective layer is reduced for the purpose of reducing the thickness and weight of the polarizing plate. If the thickness is reduced, the humidification reliability of the polarizing plate deteriorates (that is, the amount of change in light transmittance increases and the amount of change in polarization degree increases), and an environment of 40 ° C. × 90% RH has been pointed out. by the moisture permeability of the protective layer under the following 0.04g / cm ² / 24h, it is proposed that can maintain moisture transmission reliability. Patent Document 2 discloses a protective layer having moisture permeability as described above by forming a deposition film such as a transparent thin film of various metals, an ITO thin film, or a transparent metal oxide thin film by a vapor deposition method or a sputtering method. It is described that

  Incidentally, in recent years, there has been a demand for further lighter and thinner products in display devices such as liquid crystal display panels. As the glass substrate to be used, glass having a glass thickness of about 0.5 to 0.7 mm was used. However, use of a thin glass having a thinner glass thickness of 0.3 mm is desired. Attempts have been made to further reduce the thickness of each layer constituting the panel as well as the glass substrate.

  Since the rigidity of the panel is reduced as the thickness of each layer is reduced, there is a problem that the panel is warped as well as the above-described problem that the moisture-proof reliability is lowered. For example, when the liquid crystal display panel is warped, there is a problem that display defective portions called white spots are generated at the four corners of the panel, and the display stability for a long time is deteriorated.

Japanese Patent Laid-Open No. 03-148603 JP 2001-235625 A

  Deposition film made of silicon oxide, indium oxide, tin oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium fluoride, zinc oxide described in Patent Document 1, transparent thin films of various metals described in Patent Document 2, ITO thin film The transparent metal oxide thin film can impart moisture resistance to the protective film. However, since these moisture barrier films hardly expand / shrink with respect to moisture absorption / drying, the protective film warps with expansion / contraction due to moisture absorption / drying of the base film on which the moisture barrier film is provided. As a result, the problem that the warp of the protective film induces the warp of the display panel itself, whose rigidity has been reduced due to the reduction in thickness, has become apparent.

  Such warpage of the protective layer due to moisture absorption is particularly noticeable when a hygroscopic substrate having a water absorption rate of 1% or more such as a triacetyl cellulose (TAC) film is used as a substrate film for providing a moisture-proof film.

  Moreover, since the moisture-proof film described in Patent Document 1 and Patent Document 2 hardly expands / shrinks even with respect to temperature changes, the protective layer warps with expansion / contraction due to temperature changes of the base film. . The warp caused by such a temperature change cannot be ignored in combination with the warp caused by moisture absorption / drying.

  Moreover, the moisture-proof film described in Patent Document 1 and Patent Document 2 is formed on a base film by a vacuum deposition method, a sputtering method, or an ion plating method. In such a film forming method, the vapor deposition particles and sputtered particles having high temperature and high energy come into contact with the base film, so that the base film is damaged. In particular, since the hygroscopic base film as described above has low heat resistance, the flatness of the base film cannot be maintained after film formation, and as a result, the surface of the protective layer is swollen, the end floats, curls, etc. Shape deformation occurs.

  Furthermore, when a moisture-proof film is provided on a hygroscopic substrate film, high-temperature and high-energy vapor-deposited particles or sputtered particles reach the surface of the hygroscopic substrate film by using a vacuum deposition method, sputtering method, or ion plating method. Then, a dehydration phenomenon occurs from the surface of the hygroscopic substrate film. As a result, a dense film cannot be formed and sufficient moisture resistance cannot be obtained, and the adhesion between the hygroscopic substrate film and the moisture barrier film is also lowered, so that a protective film having excellent durability cannot be obtained. There's a problem.

  The present inventors have provided a moisture-proof base material in which a moisture-proof film is provided on a hygroscopic base material having a water absorption rate of 1% or more, a moisture-proof film made of a silicon oxide film or a silicon oxynitride film having a predetermined carbon content, As a result, it has been found that a moisture-proof substrate capable of realizing sufficient moisture-proof properties even when thin and capable of significantly suppressing warpage and deformation caused by the hygroscopic substrate can be realized. The present invention is based on this finding.

  Accordingly, an object of the present invention is to provide a method for producing a moisture-proof substrate that has sufficient moisture resistance even if it is thin, and that can significantly suppress warping and deformation caused by the hygroscopic substrate.

  Another object of the present invention is to provide a moisture-proof substrate obtained by the production method, and a polarizing plate and a liquid crystal display panel using the moisture-proof substrate.

The method for producing a moisture-proof substrate according to the first invention is a method for producing a moisture-proof substrate,
It is composed of a silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less on at least one surface side of a hygroscopic substrate having a water absorption of 1% or more. A moisture-proof film having a thickness of 30 nm or more is formed by a plasma chemical vapor deposition method;
It is meant to include.

  In the first invention, the film formation is preferably performed by a plasma chemical vapor deposition method using a film forming material gas containing an organosilicon monomer.

The moisture-proof substrate according to the second invention comprises a moisture-absorbing substrate having a water absorption rate of 1% or more, and a moisture-proof film formed on at least one surface side of the moisture-absorbing substrate. Because
The moisture-proof film is made of a silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less, and has a film thickness of 30 nm or more.

Moisture resistant substrate according to the second invention, it is preferable that the moisture permeability in an environment of 25 ° C. 90% RH is less than 6.0g / m ² / 24h.

  The polarizing plate provided with the moisture-proof base material by 2nd invention, and the liquid crystal display panel provided with the polarizing plate are also provided.

  According to the present invention, since the moisture-proof film is formed by the plasma chemical vapor deposition method, damage to the hygroscopic substrate due to heat and particle collision energy can be greatly reduced. Therefore, even if the film thickness of the moisture-proof substrate is reduced, a moisture-proof substrate that can greatly reduce substrate deformation and warpage can be realized.

  Further, according to the present invention, since the moisture-proof film is formed of a silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less, the water absorption is 1%. Even when a moisture-proof film is provided on the above-described hygroscopic substrate, the moisture-proof substrate has sufficient moisture resistance even if it is thin, and can greatly suppress warpage and deformation caused by the hygroscopic substrate. Can be realized.

It is a schematic sectional drawing of 1st embodiment of the moisture-proof base material by this invention. It is a schematic sectional drawing of 2nd embodiment of the moisture-proof base material by this invention. It is a schematic sectional drawing which shows the application form of the moisture proof base material by this invention. (A) shows a 1st application form, (b) shows a 2nd application form. It is a schematic sectional drawing which shows the application form of the moisture proof base material by this invention. (A) shows a 3rd application form, (b) shows a 4th application form. It is a schematic sectional drawing which shows the applied form of the polarizing plate by this invention. (A) shows a 1st application form, (b) shows a 2nd application form. It is a schematic sectional drawing which shows the application form of the liquid crystal display panel by this invention. It is the schematic which shows the 1st example of the plasma CVD apparatus used for manufacture of this invention. It is the schematic which shows the 2nd example of the plasma CVD apparatus used for manufacture of this invention. It is the schematic which shows the evaluation method of the curvature of this invention.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment at all, In the range of the objective of this invention, it can add and change suitably.

[Definition]
In this specification, “moisture permeability” means a value measured under the condition of 25 ° C. and 90% Rh in accordance with JIS Z 0208 “Method of testing moisture permeability of moisture-proof packaging material”.

  In this specification, “at%” is a unit indicating an atomic composition percentage which is a ratio of the number of atoms, and is also described as “atom% (atomic percent)”. As described later, the atomic composition percentage is a value measured by X-ray photoelectron spectroscopy. X-ray photoelectron spectroscopy is sometimes referred to as an XPS (X-ray Photoelectron Spectroscopy) method or an ESCA (Electron Spectroscopy for Chemical Analysis) method. As a specific example, the atomic composition percentage is measured by an X-ray photoelectron spectrometer (ESCA LAB220i-XL manufactured by VG Scientific), but is not limited to this measuring apparatus.

In this specification, “water absorption” means a value measured according to JIS K7209 (plastic water absorption and boiling water absorption test method), and the original mass of the test piece and the mass before and after the water absorption. It is displayed as the ratio of the increase. Specifically, the water absorption is measured as follows.
(1) As a rule, the test specimen is a circular plate with a diameter of 50 ± 1 mm or a square plate with a side of 50 ± 1 mm and a thickness of 3 ± 0.2 mm.
(2) The test piece is dried for 24 ± 1 hours in a thermostatic chamber maintained at 50 ± 2 ° C. and allowed to cool in a desiccator.
(3) Next, the mass of the test piece is measured to a unit of 0.1 mg, and the measured value is M1.
(4) After that, put the test piece into a container containing water kept at 23 ± 2 ° C., and after 24 ± 1 hour, remove the test piece from the water and measure to 0.1 mg unit. And
(5) From the measured M1 and M2, the water absorption is determined according to the following formula.
Water absorption rate = (M2-M1) / M1 × 100

  In this specification, “(meth) acrylate” means both acrylate and methacrylate.

[Moisture-proof substrate]
As shown in FIGS. 1 to 2, the moisture-proof substrate 1 according to the present invention has a moisture-absorbing substrate 2 having a water absorption rate of 1% or more and a moisture-proof substrate formed on at least one surface side of the moisture-absorbing substrate 2. And a membrane 3. Moreover, unless the objective of this invention is impaired, the moisture-proof base material 1 by this invention is as shown in FIGS. 3-4, as needed, the hard-coat layer 4, the optical adjustment layer 5, the antifouling layer 6, etc. The functional layer may be further provided. Hereinafter, each layer which comprises the moisture-proof base material by this invention is demonstrated.

(Hygroscopic substrate)
In the present embodiment, the hygroscopic substrate 2 is a substrate that functions as a base film of the moisture-proof substrate 1. The film needs to be capable of holding the moisture-proof film 3, but what kind of film is used may be selected depending on the use of the moisture-proof substrate 1.

  For example, when the moisture-proof substrate 1 is used as a protective layer for a polarizing plate of a liquid crystal display panel, the light transmittance is preferably 70% or more, and preferably has no polarization characteristics. Moreover, since it may be exposed to the process of 150 degreeC or more if it is an electronic component use and a laminated film for a display, a linear expansion coefficient is 15 ppm / K-100 ppm / K, and the glass transition point Tg is 150 degreeC-300. ° C is preferred. In this embodiment, the glass transition point in this embodiment is measured by JIS K 7121 “Plastic Transition Temperature Measurement Method”.

  Depending on the performance required in this way, the hygroscopic substrate 2 cannot always select a material having a low water absorption rate. As a result, as the display panel or the like becomes thinner, the panel is warped due to moisture absorption / drying of the moisture-proof substrate 1 when the panel is made. Such warpage accompanying moisture absorption / drying of the moisture-proof substrate 1 itself is difficult to ignore when the material of the moisture-absorbing substrate 2 has a water absorption rate of 1% or more. In this embodiment, the case where it is a hygroscopic base material with a water absorption rate of 1% or more is targeted. Although there is no restriction | limiting in particular about the upper limit of a water absorption, In a general plastic material, it is 10% or less, Preferably it is 5% or less.

  Materials used for the hygroscopic substrate 2 are triacetyl cellulose (TAC) film, polyamide film, polyaramid film, polyvinyl alcohol (PVA) film, ethylene-vinyl alcohol copolymer resin film, polyethylene glycol (PEG) film, polyimide ( PI) film, polyurethane resin film, polyethersulfone (PES) film, and the like.

  Moreover, as thickness of the hygroscopic base material 2, it is about 5 micrometers-220 micrometers, Preferably it is 10 micrometers-50 micrometers. Below this range, pinholes are generated due to discharge due to static electricity, resulting in deterioration of barrier properties. Exceeding this range is not preferable because the production amount of one lot is reduced even if the same performance can be maintained.

  The surface of the hygroscopic substrate 2 may be subjected to surface treatment such as corona treatment, flame treatment, plasma treatment, glow discharge treatment, roughening treatment, heat treatment, chemical treatment, and the like. As a specific method of such surface treatment, a conventionally known method can be appropriately used. Further, an anchor coat agent film may be formed on the surface of the hygroscopic substrate 2 for the purpose of improving the adhesion with the moisture-proof film 3 or the like. As such an anchor coat agent film, a conventionally known film may be appropriately used. Further, a barrier layer may be provided between the hygroscopic substrate 2 and the moisture-proof film 3 for the purpose of improving gas barrier properties. A conventionally known material may be appropriately used as the barrier layer forming material and forming method.

(Dampproof film)
The moisture-proof film 3 formed on at least one surface side of the hygroscopic substrate 2 is a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less formed by plasma chemical vapor deposition. A silicon oxide film or a silicon oxynitride film is included. Hereinafter, a method for forming the moisture-proof film will be described.

  Plasma chemical vapor deposition is also called plasma CVD (plasma CVD, plasma-enhanced chemical vapor deposition, PECVD), and is a type of chemical vapor deposition. In plasma enhanced chemical vapor deposition, the raw material for film formation is vaporized and supplied during plasma discharge, an additive gas is added as necessary, and the gases in the system are mutually activated by collision to generate radicals and ions. Reactions at low temperatures are possible, which is impossible only by mechanical excitation. In the hygroscopic substrate 2, a moisture-proof film 3 is formed by a reaction during discharge between the electrodes. Depending on the frequency used to generate the plasma, it is classified into low frequency (LF, several tens to several hundreds kHz), high frequency (RF, 13.56 MHz), and microwave (2.45 GHz). When microwaves are used, the method is broadly divided into a method of exciting a reaction gas and forming a film in an afterglow, and an ECR plasma CVD in which microwaves are introduced into a magnetic field (875 Gauss) that satisfies the ECR condition. Further, when classified by the plasma generation method, it is classified into a capacitive coupling method (parallel plate type) and an inductive coupling method (coil method). Further, if necessary, a magnetron structure made of magnets may be installed in the reaction system, and a space where the density of ions and electrons becomes high may be appropriately provided. Depending on the installation position of this magnetron, the damage to the film-forming substrate is reduced, and on the contrary, the damage to the film-forming substrate is increased, thereby improving the adhesion to the film-forming substrate. Can be adjusted.

  FIG. 7 is a structural diagram showing an example of a plasma CVD apparatus for forming a film by the plasma chemical vapor deposition method used in this embodiment. In FIG. 7, a plasma CVD apparatus 31 includes a chamber 32, a lower electrode 33 and an upper electrode 34 disposed in the chamber 32, a plasma generator (power source) 35 connected to the lower electrode 33, and a chamber 32. And an exhaust device 37 such as an oil rotary pump and a turbo molecular pump connected to each other through an exhaust valve 36, and a gas inlet 38 for introducing a film forming source gas into the chamber 32. The gas inlet 38 is connected to additive gas supply sources 39a, 39b, 39c and flow meters 40a, 40b, 40c for the respective gases. Further, the film forming raw material supply sources 39d and 39e, the flow meters 40d and 40e, and the vaporizers 41d and 41e as necessary are connected.

  Next, the manufacturing method of the moisture-proof base material 1 which uses such a plasma CVD apparatus is demonstrated. After mounting the film-forming surface of the hygroscopic substrate 2 on the lower electrode 33, the inside of the chamber 32 is decompressed to a predetermined vacuum level by the exhaust device 37. Next, in order to introduce a film forming raw material gas into the chamber 32, first, a film forming raw material containing an organosilicon monomer in a film forming raw material supply source 39d, 39e is supplied by adjusting the flow rate with flow meters 40d, 40e, and a vaporizer. After the film forming raw material is vaporized using 41d and 41e, it is supplied to the gas inlet 38 in a gaseous state. At the same time, the additive gas is supplied from the additive gas supply sources 39a, 39b, and 39c to the gas inlet 38 after the flow rate is adjusted by the flow meters 40a, 40b, and 40c as necessary. These gases may be mixed uniformly before the gas inlet 38 and then supplied into the chamber 2 or may be supplied separately from the gas inlet 38 for each gas type. Then, the inside of the chamber 32 is set to a predetermined pressure by controlling the degree of opening and closing of the exhaust valve 36 between the exhaust device 37 and the chamber 32. When power having a predetermined frequency is applied to the lower electrode 33 using the power source 35 in a state where the gas flow is stable inside the chamber 32, a plasma discharge is formed between the lower electrode 33 and the upper electrode 34, thereby absorbing moisture. The moisture-proof film 3 is deposited on the conductive substrate 2 to form a film.

  Although the plasma CVD apparatus shown in FIG. 7 is a system for forming a film on the sheet-shaped hygroscopic substrate 2, a roll-up type plasma CVD apparatus may be used.

  FIG. 8 is a configuration diagram showing another example of a plasma CVD apparatus for forming a film by the plasma chemical vapor deposition method used in this embodiment. In FIG. 8, the plasma CVD apparatus includes a chamber 50 having a film formation zone, and a transport system including a feed roller 51, a take-up roller 52, and a guide roller 61 for transporting the hygroscopic substrate 2 in the chamber 50. I have. In the film formation zone, a lower electrode 53 and a coating drum (upper electrode) 54 that also serves as an upper electrode are connected to a power source. Further, the chamber 50 is provided with an exhaust device 56b such as an oil rotary pump and a turbo molecular pump connected through an exhaust valve 55b, and further connected to the film formation zone through an exhaust valve 55a. Exhaust devices 56a such as an oil rotary pump and a turbo molecular pump, and gas introduction ports 57a, 57b and 57c for introducing the source gas into the film formation zone are installed. The gas inlets 57a, 57b, and 57c are connected to additive gas supply sources 58a, 58b, and 58c, and the film forming raw material supply sources 59a and 59b are connected via the flow meters 60a and 60b and the vaporizers 61a and 61b. It is connected to the.

  Next, the manufacturing method of the moisture-proof base material 1 which uses such a plasma CVD apparatus is demonstrated. First, the hygroscopic substrate 2 is mounted on the transport system of the plasma CVD apparatus so that the film formation surface is outside the coating drum 54. Next, the inside of the chamber 50 is depressurized to a predetermined degree of vacuum by the exhaust devices 56 and 56 '. Subsequently, for example, oxygen, carbon monoxide, carbon dioxide, methane, ethylene, and the like are supplied from the additive gas supply sources 58a, 58b, and 58c after the flow rate is adjusted by the flowmeters 62a, 62b, and 62c, and further, the film forming raw material The flow rate is adjusted from the supply sources 59a and 59b by the flow meters of the flow meters 60a and 60b, and the film forming raw material containing the organosilicon monomer is supplied in a gaseous state via the vaporizers 61a and 61b, and the gas introduction ports 57a and 57b, The inside of the film formation zone is maintained at a predetermined pressure by controlling the degree of opening and closing of the exhaust valves 55a and 55b introduced from 57c and between the exhaust devices 56a and 56b and the film formation zone. Subsequently, conveyance of the hygroscopic substrate 2 in a desired direction is started, and power having a predetermined frequency is applied to the coating drum (upper electrode) 54 and the lower electrode 53 in the film formation zone by a power source. Thereby, the film forming source gas and the additive gas are introduced in the film forming zone, and a plasma discharge is formed between the lower electrode 53 and the coating drum (upper electrode) 54. And the moisture-proof film | membrane 3 is formed into a film on the hygroscopic base material 2 currently conveyed.

  In any plasma CVD apparatus, the moisture-proof film 3 is preferably formed at a discharge frequency of 10 Hz or more and 300 kHz or less so that excellent adhesion can be obtained by the ion implantation effect on the hygroscopic substrate 2.

  In addition, it is preferable to provide a magnetron mechanism in the vicinity of the surface of the moisture-absorbing substrate 2 where the moisture-proof film 3 is formed to form a plasma discharge from the viewpoint of improving productivity and reducing production cost. That is, by forming a plasma discharge by providing a magnetron mechanism, the plasma density is increased and the deposition rate is improved. In addition, the installation position of this magnetron reduces the damage to the film-forming substrate, and conversely increases the adhesion to the film-forming substrate by increasing the damage to the film-forming substrate. Adjustment is possible.

  In addition, when the moisture-proof film 3 is formed, it is preferable that the upper electrode 34 in FIG. 7 and the coating drum 54 in FIG. 8 that are in contact with the hygroscopic substrate 2 are cooled by providing a cooling mechanism. By forming the moisture-proof film 3 while cooling the lower electrode 33 in FIG. 7 and the coating drum 54 in FIG. 8 with which the hygroscopic substrate 2 is in contact, heat damage to the hygroscopic substrate 2 is further reduced and moisture-proof. The deformation and waviness of the conductive substrate 1 can be reduced.

  An organic silicate compound is used as a film forming raw material gas used when forming a moisture-proof film by plasma chemical vapor deposition. In particular, an organosilicon monomer is suitable because it is easy to introduce a prescribed carbon content into the moisture-proof film 3. Examples of the organic silicon compound constituting the film forming monomer gas include 1.1.3.3-tetramethyldisiloxane, hexamethyldisiloxane (HMDSO), vinyltrimethylsilane, methyltrimethylsilane, hexamethyldisilane, and methylsilane. , Dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, Hexamethyldisilazane or the like can be used alone or in combination.

  In the present embodiment, among the organosilicon compounds as described above, 1.1.3.3-tetramethyldisiloxane or hexamethyldisiloxane is used because of its handleability and the characteristics of the formed continuous film. Particularly preferred raw materials. In the present embodiment, as the inert gas, for example, argon gas, helium gas, or the like can be used. As the additive gas, oxygen, carbon monoxide, carbon dioxide, water, methane, ethylene, or the like can be used.

  Further, in the present embodiment, in order to adjust the carbon content of the moisture-proof film, oxygen, carbon monoxide, carbon dioxide, methane, ethylene, or the like may be added to the film forming raw material gas during film formation as an additive gas. Good. Appropriately selected the type of organic silicon monomer contained in the film-forming raw material gas used for forming the moisture-proof film, and adding an appropriate amount of additive gases such as oxygen, carbon monoxide, carbon dioxide, methane, and ethylene, makes it suitable for moisture-proof films. It becomes possible to form a moisture-proof film having a carbon content. The moisture-proof film 3 functions in the moisture-proof substrate 1 to reduce the moisture permeability (water vapor permeability) of the moisture-proof substrate 1 itself. In addition, by preventing moisture from entering the hygroscopic substrate 2, it functions to reduce warpage of the moisture-proof substrate caused by moisture absorption and drying of the moisture-proof substrate 1.

The silicon oxide film formed as described above is a thin film in which silicon, oxygen, and carbon are mainly detected by measurement by X-ray photoelectron spectroscopy, and Si—O—Si stretch in infrared absorption measurement. absorption peak due to vibration 1045~1060cm ^-1, absorption peaks due to Si-CH ₃ stretching vibration is generally detected 1274 ± 8 cm ^-1. The silicon oxide film containing a carbon component in this embodiment has a carbon content of 2.0 at% or more and 20.0 at% or less as measured by X-ray photoelectron spectroscopy, and the carbon is in the form of Si—CH ₃ bonds. Existing.

In the present embodiment, the silicon oxynitride film is a thin film in which silicon, oxygen, nitrogen, and carbon are mainly detected by measurement with X-ray photoelectron spectroscopy. In the infrared absorption measurement in the infrared absorption measurement, Si-O, the absorption peak by Si-N stretching vibration in the range of 830~1060cm ^-1, absorption peaks due to Si-CH ₃ stretching vibration is generally detected 1274 ± 8 cm ^-1. The silicon oxynitride film containing a carbon component in this embodiment has a carbon content of 2.0 at% or more and 20.0 at% or less as measured by X-ray photoelectron spectroscopy, and the carbon is in the form of Si—CH ₃ bonds. Exists.

The presence of the contained carbon in the form of Si—CH ₃ bonds is also a feature when the film is formed by plasma chemical vapor deposition. That is, when the silicon oxide or silicon oxynitride film is formed, decomposition products such as carbon atoms contained in the film forming source gas and additive gas, or ion species formed by plasma during film formation form the substrate surface. Carbon atoms generated for etching are taken into the film to form Si—CH ₃ bonds. With this feature, the water repellency of the Si—CH ₃ bond formed on the film surface reduces the water vapor from adsorbing on the moisture-proof film surface, and the water molecules diffusing into the moisture-proof film are greatly reduced. Accordingly, since the intrusion of moisture into the hygroscopic substrate 2 is greatly reduced, it is possible to reduce the warpage of the moisture-proof substrate caused by moisture absorption / drying of the moisture-proof substrate 1 to a level with no problem.

In addition, the presence of contained carbon in the form of Si—CH ₃ bonds in the silicon oxide film or the silicon oxynitride film is more hygroscopic than in the case where a film made of only an inorganic compound is used as the moisture-proof film 3. It is considered that the difference in thermal contraction rate (thermal expansion coefficient) with the base material 2 is relaxed and the warp due to the temperature difference is also mitigated.

  If the carbon content measured by the X-ray photoelectron spectroscopy is less than 2.0 at%, moisture adsorption on the surface of the moisture-proof film 3 cannot be sufficiently reduced, so that the moisture permeability increases. In addition, since the organic component in the moisture-proof film 3 is reduced, the flexibility of the moisture-proof film 3 is lowered, and the moisture-proof film 3 is easily cracked and moisture permeability is increased. Therefore, the warp due to moisture absorption and drying of the moisture-proof substrate 1 cannot be sufficiently reduced, which is not preferable. The carbon content is preferably 2.4 at% or more.

  When the carbon content measured by X-ray photoelectron spectroscopy exceeds 20.0 at%, the moisture-proof film becomes stronger in organic film properties, the film becomes less dense, and the moisture permeability increases. Decreasing is not preferable. The carbon content is preferably 18.0 at% or less.

  It can be confirmed that the moisture-proof film 3 has a predetermined carbon content by determining the ratio of the number of atoms of Si, O, C, and N. As a method for obtaining such an atomic ratio, a conventionally known method can be used. In the present embodiment, evaluation is performed based on results obtained by an analyzer such as an X-ray photoelectron analyzer (XPS). In the present embodiment, XPS is measured by XPS (ESCA LAB220i-XL manufactured by VG Scientific). As the X-ray source, MgKα ray which is an X-ray source having an Ag-3d-5 / 2 peak intensity of 300 Kcps to 1 Mcps is used, and a slit having a diameter of about 1 mm is used. The measurement is performed with the detector set on the normal line of the sample surface subjected to the measurement, and appropriate charge correction is performed. The analysis after the measurement uses the software Eclipse version 2.1 attached to the above-mentioned XPS apparatus, and uses peaks corresponding to the binding energies of Si: 2p, C: 1s, N: 1s, and O: 1s. Is going. At this time, among the peaks of C: 1s, each peak shift is corrected with the peak corresponding to the hydrocarbon as a reference, and the binding state of the peaks is attributed. Then, background of Shirley is removed for each peak, and sensitivity coefficient correction of each element is performed on the peak area (Si = 0.87, N = 1.77, O = 2 for C = 1.0). .85) to obtain the atomic ratio. With respect to the obtained atomic ratio, the sum of the numbers of Si, C, N, and O atoms is defined as 100, and the atomic composition percentage of C is obtained.

  The thickness of the moisture-proof film 3 in the present embodiment can be measured with a contact-type step meter, and specifically, measured using a step meter (manufactured by ULVAC, Inc., DEKTAK IIA). The measurement was performed with the scan range set to 2 mm and the scan speed set to Low. In the present embodiment, the moisture-proof film needs to have a thickness of 30 nm or more. When the thickness of the moisture-proof film 3 is less than 30 nm, sufficient moisture resistance cannot be obtained. On the other hand, when the thickness of the moisture-proof film 3 is 500 nm or more, the productivity may be significantly reduced. The thickness of the moisture-proof film 3 is particularly preferably 100 nm or more and 300 nm or less.

(Hard coat layer)
The hard coat layer 4 that may optionally be provided on the moisture-proof substrate 1 according to the present invention is provided for the purpose of preventing scratches on the surface of the polarizing plate. The hard coat layer 4 is provided on at least one surface of the moisture-proof substrate 1. More specifically, the hard coat layer 4 can be provided on the surface of the hygroscopic substrate 2 on which the moisture-proof film 3 is formed. Thereby, since the moisture-proof base material 1 is protected by the hard-coat layer 4, the moisture-proof base material 1 which is hard to be damaged as a result can be provided.

  The hard coat layer 4 can be formed by, for example, a method of adding a cured film excellent in hardness, slipperiness, and the like with an appropriate ionizing radiation curable resin such as silicone to the surface of the transparent protective film. As the hard coat layer 4, a conventionally known layer can be appropriately used. Specifically, as the material of the hard coat layer 4, those having an acrylate functional group that is an ionizing radiation curable resin, that is, those having an acrylic skeleton and those having an epoxy skeleton are suitable. Considering the hardness, heat resistance, solvent resistance, and scratch resistance of the layer 4, it is preferable to have a high crosslink density structure. As materials for obtaining such a structure, for example, ethylene glycol di (meth) acrylate, 1,6-hexanediol diacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta Bifunctional or higher acrylate monomers such as (meth) acrylate and dipentaerythritol hexa (meth) acrylate can be exemplified.

  When the above-mentioned ionizing radiation curable resin is used as the material for the hard coat layer 4, a known photopolymerization initiator or photosensitizer can be used in combination. Such photopolymerization initiators and photosensitizers are preferably used when the ionizing radiation curable resin is cured by irradiating ultraviolet rays. This is because ionizing radiation curable resins tend to be sufficiently cured when irradiated with an electron beam. The addition amount of the photopolymerization initiator or photosensitizer is generally 0.1 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the ionizing radiation curable resin. In addition to these materials, various inorganic and organic additives such as a solvent, a curing catalyst, a wettability improver, a plasticizer, an antifoaming agent, and a thickener can be added as necessary.

The hard coat layer 4 can be formed by applying and curing the above material on the moisture-proof substrate 1 as a coating solution. Here, the coating amount of the coating solution is usually 0.5 g / m ² or more and 15.0 g / m ² or less as the solid content. In addition, as an ultraviolet-ray source used for hardening, an ultrahigh pressure mercury lamp etc. can be mentioned, for example. As a wavelength of ultraviolet rays, a wavelength range of 190 nm or more and 380 nm or less can be used normally, and as an electron beam source, various electron beam accelerators such as a cockcroft-walt type can be used.

  The thickness of the hard coat layer 4 is usually 1 μm or more, preferably 3 μm or more, and usually 10 μm or less, preferably 8 μm or less. Within this range, the transparency of the moisture-proof substrate 1 is unlikely to be impaired, and the scratch resistance is likely to be good.

(Optical adjustment layer)
Further, the moisture-proof substrate 1 according to the present invention may be provided with an optical adjustment layer 5 such as an antireflection film or an antiglare film. The optical adjustment layer 5 is provided for the purpose of preventing reflection of external light and the like, and is realized by forming the optical adjustment layer 5 according to the conventional method. For example, an anti-glare layer, which is one of the antiglare films, is provided for the purpose of preventing external light from being reflected on the surface of the polarizing plate and obstructing the viewing of the light transmitted through the polarizing plate. The antiglare layer can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a roughening method such as a sand blasting method or an embossing method, or a blending method of transparent fine particles.

  Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 μm to 20.0 μm. Fine particles may be used, and organic fine particles composed of crosslinked or uncrosslinked polymer particles may be used. The amount of transparent fine particles used is generally 2 to 70 parts by mass, more preferably 5 to 50 parts by mass, per 100 parts by mass of the transparent resin.

  The antiglare layer containing transparent fine particles can be provided as a layer that also serves as a hard coat layer or as a coating layer on the surface of the moisture-proof substrate 1. The antiglare layer may also serve as a diffusion layer (viewing angle compensation function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle. The antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and the like described above can be provided separately from the transparent protective layer as an optical layer composed of a sheet provided with these layers.

(Other membranes)
In addition to the hard coat layer 4 and the optical adjustment layer 5 described above, other films can be used as necessary. Examples of these include an antifouling film 6, an antistatic film, and a smoothing film. The antifouling film 6 and the antistatic film may be bonded to the moisture-proof substrate 1 of the present embodiment via an optical adhesive to obtain a desired function.

  As such other films, conventionally known films may be used as appropriate, but they are often formed on the surface of the hard coat layer 4. However, an antireflection function, a viewing angle control function, and the like can be attached to the hard coat layer 4.

  The anti-reflective film has a function to suppress the reflection of external light, the anti-static film has a function to prevent dust and dirt from adhering, and the anti-fouling film inhibits adhesion of oil such as fingerprints. Conventionally known materials may be used as appropriate, but they are often formed on the surface of the hard coat layer 4. However, an antireflection function or a transparent conductive function can be added to the hard coat layer 4. The smoothing film is used for flattening the surface, and may be formed on the surface of the moisture-proof film 3, for example.

[Polarizer]
In the present embodiment, as illustrated in FIG. 5, the polarizing plate 10 includes a polarizer 11 having a polarization function that allows only polarized light in a specific direction or light that has been polarized to pass through, and moisture resistance bonded to the polarizer 11. A substrate 1 is provided. The moisture-proof substrate 1 is used for the purpose of protecting the polarizer 11 from moisture and giving the polarizing plate 10 rigidity. Usually, the polarizer 11 generally uses uniaxially stretched polyvinyl alcohol or the like. Such a polarizer has drawbacks such as being easily torn in the direction of the stretching axis and inferior in water resistance, and is thin and weak in strength. In the present invention, in order to compensate for these drawbacks, both surfaces of the polarizer 11 are sandwiched by the moisture-proof substrate 1 and used as the polarizing plate 10. As the hygroscopic substrate 2 that is the base film of the moisture-proof substrate 1, triacetyl cellulose (hereinafter sometimes referred to as TAC) is applied from the viewpoint of transparency, adhesion, and moisture permeability.

  As the polarizer 11, for example, a film made of an appropriate vinyl alcohol-based polymer according to the prior art, such as polyvinyl alcohol or partially formalized polyvinyl alcohol, and a dyeing treatment or stretching treatment with a dichroic substance made of iodine, a dichroic dye, or the like. Appropriate treatments such as cross-linking treatment and cross-linking treatment can be performed in an appropriate order and manner, and an appropriate material that transmits linearly polarized light when natural light is incident can be used. In particular, those excellent in light transmittance and degree of polarization are preferable.

  It is preferable that the total thickness of the polarizer 11 and the moisture-proof substrate 1 provided on one or both surfaces thereof is 135 μm or less. Of these, the polarizer 11 preferably has a thickness of about 15 to 30 μm, and the moisture-proof substrate 1 has a thickness of 60 to 25 μm, more preferably about 50 to 25 μm. The thickness is preferably used. In the case where the moisture-proof substrate 1 is formed on both sides of the polarizer 11, the thickness of the moisture-proof substrate 1 is almost twice as large in total on the front and back sides, and the polarizer is also considered in consideration of the thickness of the adhesive layer. In the state where the moisture-proof substrate 1 is formed on both sides of the substrate 11, the thickness of the polarizer 11 and the moisture-proof substrate 1 is appropriately selected so that the total thickness of the obtained polarizing plate 10 is 135 μm or less. If the thickness of the moisture-proof substrate 1 becomes too thin, the production becomes difficult and the handleability becomes difficult, so it is usually preferable not to make it thinner than about 25 μm.

  As the hygroscopic substrate 2 that becomes the base film of the moisture-proof substrate 1 provided on one side or both sides of the polarizer 11, an appropriate transparent film can be used. As an example of the polymer, an acetate-based resin such as triacetyl cellulose is generally used, but is not limited thereto.

  The TAC film is required to have no birefringence at all because the birefringence of the polarizer is finely controlled. When a film is formed by extrusion, which is a general method for producing polymer films, the resin molecules are oriented in a certain direction and birefringence occurs. Therefore, as a method for producing a TAC film, a solution casting film forming method is generally used in which a polymer is dissolved in a solvent and spread thinly on a wide plate, and the film is produced while volatilizing the solvent.

  A polyvinyl alcohol-based adhesive or a urethane-based adhesive is used for bonding the polarizer 11 and the moisture-proof substrate 1, particularly the moisture-proof substrate 1 made of a triacetyl cellulose film.

  The polarizing plate 10 according to the present embodiment can be used as an optical member that is laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, a reflection plate, a transflective plate, a retardation plate (including a λ plate such as a half-wave plate and a quarter-wave plate), a visual compensation film, and a brightness enhancement plate. One or two or more suitable optical layers that may be used for forming a liquid crystal display panel or the like can be used. Particularly, from the polarizer 11 and the moisture-proof substrate 1 of the present embodiment described above. The polarizing plate 10 further comprises a reflecting plate or a semi-transmissive reflecting plate laminated with a reflecting plate or a semi-transmissive reflecting plate, and comprises the polarizer 11 and the moisture-proof substrate 1 of the present embodiment described above. A viewing angle compensation film is further laminated on an elliptical or circularly polarizing plate on which a retardation plate is further laminated on the polarizing plate 10, or on the polarizing plate 10 comprising the polarizer 11 and the moisture-proof substrate 1 of the above-described embodiment. Polarizing plate 10 or the above-described implementation A polarizing plate 10 consisting of the polarizer 11 and the moisture resistant substrate 1 state, preferably polarizer 10 is further laminated brightness enhancement film.

  The polarizing plate 10 according to the present embodiment may be provided with an adhesive layer for bonding with other members such as the liquid crystal cell 21. The pressure-sensitive adhesive layer can be formed of an appropriate pressure-sensitive adhesive according to the conventional type such as acrylic. In particular, the moisture absorption rate is from the viewpoints of prevention of foaming phenomenon and peeling phenomenon due to moisture absorption, deterioration of optical characteristics due to thermal expansion difference and the like, prevention of warpage of the liquid crystal cell, and formation of the liquid crystal display panel 20 having high quality and excellent durability. It is preferably an adhesive layer having a low heat resistance and excellent heat resistance. Moreover, it can also be set as the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility. What is necessary is just to provide an adhesion layer in a required surface as needed.

  When the adhesive layer provided on the polarizing plate 10 is exposed on the surface, it is preferable to temporarily cover with a separator for the purpose of preventing contamination until the adhesive layer is put to practical use. The separator is formed by, for example, a method in which a release coat with an appropriate release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide is provided on an appropriate thin leaf according to the above-described transparent protective film or the like. be able to.

  In addition, each layer, such as the polarizing plate 10, the polarizer 11 that forms the optical member, the moisture-proof substrate 1, the optical layer, and the adhesive layer, includes, for example, salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, and cyanoacrylate compounds. In addition, a material having an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorber such as a nickel complex compound may be used.

  The polarizing plate 10 according to the present embodiment can be preferably used for forming various devices such as the liquid crystal display panel 20.

[LCD panel]
The liquid crystal display panel 20 according to the present embodiment is a conventional transmission type, a reflection type, or a transmission / reflection type, in which the polarizing plate 10 according to this embodiment is arranged on one side or both sides of the liquid crystal cell 21 as shown in FIG. It can be formed as having an appropriate structure according to the above. Accordingly, the liquid crystal cell 21 forming the liquid crystal display panel 20 is arbitrary. For example, an active matrix drive type represented by a thin film transistor type, a simple matrix drive type represented by a twist nematic type or a super twist nematic type, etc. An appropriate type of liquid crystal cell 21 may be used.

  Moreover, when providing the polarizing plate 10 in the both sides of the liquid crystal cell 21, they may be the same and may differ. Further, when the liquid crystal display panel 20 is formed, for example, appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged in one or more layers at appropriate positions.

  The use of the moisture-proof substrate according to the present invention is not particularly limited. However, it is thin and light, high moisture resistance is required, and it is suitable for applications that require deformation such as warpage. In addition to the liquid crystal display panel described above, the present invention can be widely applied to electronic displays such as organic EL.

  EXAMPLES Hereinafter, although an Example etc. are given and this invention is demonstrated further in detail, this invention is not limited to the following Example etc. at all.

[Example 1]
As the hygroscopic substrate, a 40 μm thick triacetyl cellulose (TAC) film was used. On this hygroscopic substrate, a silicon oxide film was formed as a moisture-proof film by plasma chemical vapor deposition. In the plasma chemical vapor deposition method, a parallel plate type plasma CVD apparatus as shown in FIG. 7 was used, and the distance between the electrode plates was set to 25 mm. The hygroscopic substrate was set on the lower electrode, and the inside of the chamber was evacuated to 1 × 10 ⁻² Pa or less with a vacuum pump. After that, hexamethyldisiloxane 2 sccm as a film forming raw material gas, argon gas 10 sccm and oxygen gas 30 sccm as an additive gas are introduced between the electrodes from the gas inlet 38, and the pressure in the chamber is adjusted by adjusting the opening degree of the exhaust valve of the chamber. Set to 7 Pa. Thereafter, a plasma discharge was formed from the plasma generator at a frequency of 40 kHz and an input power of 200 W, and a silicon oxide film having a thickness of 102 nm was formed as a moisture-proof film, whereby a moisture-proof substrate 1 was produced.

[Example 2]
In Example 1, a silicon oxide film having a film thickness of 103 nm is formed on one surface (described as a surface in Table 1) of the hygroscopic substrate, and a film thickness of 102 nm is formed on the other surface (described as a back surface in Table 1). A moisture-proof substrate 2 was produced in the same manner as in Example 1 except that the silicon oxide film was formed.

[Example 3]
In Example 1, the moisture-proof base material 3 was produced in the same manner as in Example 1 except that the film forming raw material gas was changed to 2 sccm of hexamethyldisilazane and a 100 nm-thick silicon oxynitride film was formed as the moisture-proof film. did.

[Example 4]
In Example 3, a silicon oxynitride film having a film thickness of 105 nm is formed on one surface (described as the surface in Table 1) of the hygroscopic substrate, and the film thickness is formed on the other surface (described as the back surface in Table 1). A moisture-proof substrate 4 was produced in the same manner as in Example 3 except that a 101 nm silicon oxide film was formed.

[Example 5]
In Example 1, the oxygen addition amount at the time of forming the silicon oxide film was increased to 75 sccm, and a moisture-proof film having a film thickness of 103 nm with a carbon content measured as follows was 2.4 at% was implemented. In the same manner as in Example 1, a moisture-proof substrate 5 was produced.

[Example 6]
In Example 1, the oxygen addition amount at the time of forming the silicon oxide film was increased to 35 sccm, and a moisture-proof film having a film thickness of 78 nm having a carbon content measured as follows of 12.3% was implemented. In the same manner as in Example 1, a moisture-proof substrate 6 was produced.

[Example 7]
In Example 1, the amount of oxygen added during the formation of the silicon oxide film was increased to 40 sccm, and the moisture content was measured as follows, and the carbon content was 7.8%. In the same manner as in Example 1, a moisture-proof substrate 7 was produced.

[Example 8]
In Example 1, the moisture-proof substrate 8 was produced in the same manner as in Example 1 except that the moisture-proof film was formed so that the thickness of the silicon oxide film was 195 nm.

[Example 9]
In Example 1, a moisture-proof substrate 9 was produced in the same manner as in Example 1 except that the moisture-proof film was formed so that the thickness of the silicon oxide film was 308 nm.

[Comparative Example 1]
In Example 1, a moisture-proof substrate 10 was produced in the same manner as in Example 1 except that the moisture-proof film was formed so that the thickness of the silicon oxide film was 25 nm.

[Comparative Example 2]
In Example 1, except that the amount of oxygen added during the formation of the silicon oxide film was reduced to 6 sccm, and a moisture-proof film having a film thickness of 102 nm with a carbon content of 25.2 at% measured as follows was used. In the same manner as in Example 1, a moisture-proof substrate 11 was produced.

[Comparative Example 3]
As a hygroscopic substrate, a triacetylcellulose film having a thickness of 40 μm was used. A silicon oxide film was formed as a moisture-proof film on this hygroscopic substrate by a vacuum deposition method. A hygroscopic substrate was set in a film forming chamber, and SiO was used as a film forming material for the moisture-proof film, and the film was formed while oxygen gas was added. At this time, the distance between the hygroscopic substrate and the film forming material was set to 500 mm. A hygroscopic substrate and a vapor deposition material are set in a vacuum chamber, evacuated to 1 × 10 ⁻³ Pa or less, and then the vapor deposition material is heated and evaporated using an EB gun, and oxygen gas is introduced at 20 sccm, Reactive vapor deposition was performed to form a silicon oxide film having a thickness of 105 nm as a moisture-proof film, and a moisture-proof substrate 12 was produced.

[Comparative Example 4]
In Comparative Example 3, a silicon oxide film having a film thickness of 103 nm is formed on one surface (described as a surface in Table 1) of the hygroscopic substrate, and a film thickness of 103 nm is formed on the other surface (described as a back surface in Table 1). A moisture-proof substrate 13 was produced in the same manner as in Comparative Example 3 except that the silicon oxide film was formed.

[Comparative Example 5]
As a hygroscopic substrate, a triacetylcellulose film having a thickness of 40 μm was used. A silicon oxide film was formed as a moisture-proof film on the hygroscopic substrate by a sputtering method. A hygroscopic substrate is set in a film forming chamber, the inside of the chamber is evacuated to 1 × 10 ⁻³ Pa or less, Si is used as a film forming target material, and argon gas and oxygen gas are introduced as a reactive gas. Then, a silicon oxide film having a film thickness of 105 nm was formed as a moisture-proof film by a dual magnetron sputtering method (frequency: 40 kHz) with a film-forming pressure of 0.3 Pa and an input power of 2 kW, and a moisture-proof substrate 14 was produced.

[Comparative Example 6]
In Comparative Example 5, a silicon oxide film having a film thickness of 105 nm was formed on one surface (described as the surface in Table 1) of the hygroscopic substrate, and a film thickness of 105 nm was formed on the other surface (described as the back surface in Table 1). A moisture-proof substrate 15 was produced in the same manner as in Comparative Example 5 except that the silicon oxide film was formed.

[Evaluation of film thickness of moisture barrier film]
For the hygroscopic substrates 1 to 15 obtained as described above, the film thickness of the moisture-proof film is set using a step gauge (manufactured by ULVAC, Inc., DEKTAK IIA), the scan range is set to 2 mm, and the scan speed is set to Low. And measured. The measured film thickness was as shown in the “film thickness” column of Table 1.

[Evaluation of flatness after film formation]
The flatness of the hygroscopic substrates 1 to 15 obtained as described above was evaluated. First, the moisture-proof substrate was cut out to 15 cm × 15 cm to obtain a moisture-proof substrate sample 10 shown in FIG. Then, as shown in the figure, the moisture-proof substrate sample 72 was placed on a stainless steel substrate 71, and the orthogonal distance L between the apex 8 of the moisture-proof substrate sample 72 and the stainless steel substrate 6 was measured. . Further, the swell was visually observed. And according to the magnitude | size of the orthogonal distance L and the state of a wave | undulation, the generation | occurrence | production degree of the curl of a hygroscopic base material was evaluated on the following evaluation criteria.
Good: The orthogonal distance L is 1 mm or less, and no undulation is observed.
Defect: The orthogonal distance is greater than 1 mm or undulation is observed.
The evaluation results were as shown in the column “Flatness after film formation” in Table 1.

[Dampproofness evaluation]
For the hygroscopic substrates 1 to 15 obtained as described above, the moisture permeability was measured under the condition of 25 ° C. and 90% Rh in accordance with JIS Z 0208 “Moisture permeability test method for moisture-proof packaging material”. The moisture resistance was evaluated. The evaluation results are as shown in the column of “moisture permeability” in Table 1.

[Measurement of carbon content]
For the hygroscopic substrates 1 to 15 obtained as described above, after removing contaminants adsorbed on the surface of the moisture-proof film using argon, composition analysis of the moisture-proof film using an X-ray photoelectron spectrometer is performed. The carbon content was determined. The carbon content was measured using XPS (ESCA LAB220i-XL manufactured by VG Scientific). As the X-ray source, MgKα ray which is an X-ray source having an Ag-3d-5 / 2 peak intensity of 300 Kcps to 1 Mcps was used, and a slit having a diameter of about 1 mm was used. The measurement was performed with the detector set on the normal line of the sample surface used for the measurement, and appropriate charge correction was performed. The analysis after the measurement uses the software Eclipse version 2.1 attached to the above-mentioned XPS apparatus, and uses peaks corresponding to the binding energies of Si: 2p, C: 1s, N: 1s, and O: 1s. went. C: Among the peaks of 1 s, each peak shift was corrected based on the peak corresponding to the hydrocarbon, and the binding state of the peak was assigned. Then, background of Shirley is removed for each peak, and sensitivity coefficient correction of each element is performed on the peak area (Si = 0.87, N = 1.77, O = 2 with respect to C = 1.0). .85) and the atomic ratio was determined. About the obtained atomic ratio, the sum of the number of atoms of Si, C, N, and O was set to 100, and it was set as the atomic composition percentage of C. The carbon content (at%) of the moisture-proof film calculated by the analysis was as shown in Table 1.

[Panel evaluation]
A liquid crystal display panel shown in FIG. 6 was prepared using the hygroscopic substrate obtained as described above, and stored in an environmental tester at 60 ° C. and 90% RH for one week. Then, the panel display state was confirmed visually and the presence or absence of white spot generation | occurrence | production of a display part was evaluated. The evaluation criteria were as follows.
Good: No white spots are seen on the display.
Defect: White spots are seen on the display.
The evaluation results were as shown in the “Panel Evaluation” column of Table 1.

1: Moisture proof substrate 2: Hygroscopic substrate 3: Moisture proof film 4: Hard coat layer 5: Optical adjustment layer 6: Antifouling layer 10: Polarizing plate 11: Polarizer 20: Liquid crystal display panel 21: Liquid crystal cell 22: Glass substrate 23: Adhesive layer 31: Plasma CVD device 32: Chamber 33: Lower electrode 34: Upper electrode 35: Plasma generator 36: Exhaust valve 37: Exhaust device 38: Gas inlets 39a, 39b, 39c: Additional gas supply device 39d, 39e: Film forming material supply devices 40a, 40b, 40c, 40d, 40e: Flow meters 41d, 41e: Vaporizer 50: Chamber 51: Delivery roller 52: Winding roller 53: Lower electrode 54: Coating drum (upper electrode) )
55a, 55b: exhaust valves 56a, 56b: exhaust devices 57a, 57b, 57c: gas introduction ports 58a, 58b, 58c: additive gas supply sources 59a, 59b: film forming raw material supply sources 60a, 60b: flow meter 61: guide roller 62a, 62b: vaporizers 63a, 63b, 63c: flow meter 71: substrate made of stainless steel 72: moisture-proof substrate sample

Claims (6)

A method for producing a moisture-proof substrate,
It is composed of a silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less on at least one surface side of a hygroscopic substrate having a water absorption of 1% or more. A moisture-proof film having a thickness of 30 nm or more is formed by a plasma chemical vapor deposition method;
The manufacturing method of a moisture-proof base material comprising this.   The method for producing a moisture-proof substrate according to claim 1, wherein the film formation is performed by a plasma chemical vapor deposition method using a film forming source gas containing an organosilicon monomer. A moisture-proof substrate comprising a moisture-absorbing substrate having a water absorption rate of 1% or more and a moisture-proof film formed on at least one surface side of the moisture-absorbing substrate,
The moisture-proof film is a moisture-proof substrate made of a silicon oxide film or a silicon oxynitride film containing a carbon component having a carbon content of 2.0 at% or more and 20.0 at% or less and having a film thickness of 30 nm or more. Moisture permeability in an environment of 25 ° C. 90% RH is less than 6.0g / m ² / 24h, moisture-proof substrate according to claim 3.   The polarizing plate provided with the moisture-proof base material as described in any one of Claim 3 or Claim 4.   A liquid crystal display panel comprising the polarizing plate according to claim 5.

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