JP5003270B2 - Vacuum film forming apparatus and method for producing polymer film laminate - Google Patents

Description

  The present invention relates to a vacuum film forming apparatus for forming a thin film on a polymer film substrate, a method for producing a polymer film laminate, and a polymer film laminate.

 Attempts to improve the gas barrier properties of polymer films have been extensively studied, and gas barrier films imparted with gas barrier properties have been used as packaging materials for foods, pharmaceuticals, electronic parts, and industrial materials. In recent years, with the development of electronic paper and organic EL, which are expected as next-generation flat panel displays (FPDs), we aim to replace glass with polymer film substrates in order to achieve flexibility in these FPDs. The demand has increased. As a matter of course, the glass substrate has a gas barrier function required for suppressing deterioration of internal elements due to oxygen and water vapor derived from the environment. Electronic paper and EL can be cited as a display to which a polymer film substrate can be applied. The required barrier level is said to be 100 to 10,000 times that of a barrier film for food packaging materials. The material barrier film does not satisfy the gas barrier properties required for EL and the like.

 As a method for imparting a gas barrier property, it is considered effective to provide a thin film layer (gas barrier layer) having a gas barrier property on a film. As a method for forming a gas barrier layer, an organic substance or an organic-inorganic hybrid layer is wet. A method of forming by a coating method and a method of forming an inorganic thin film by a dry coating method have been proposed. Compared to organic substances, an inorganic thin film having a three-dimensional network structure is expected to be uniform, high in density, dense, and have high gas barrier properties. Among inorganic thin films, inorganic oxides such as silicon oxide, aluminum oxide, and magnesium oxide are considered to be optimal as a barrier layer because they have a high density structure and high transparency.

 In order to realize such a high gas barrier property, an inorganic oxide film obtained by a dry coating method has been actively studied as one that can be expected to have a high gas barrier property. As a method for forming an inorganic oxide thin film on a film by a dry coating method, a reactive vapor deposition method using electron beam vapor deposition or induction heating vapor deposition, a sputtering method, or a plasma CVD method is generally used.

Among them, a silicon oxide film (SiOx) formed by a plasma CVD method is generally advantageous in that it has few pinholes and cracks. On the other hand, in order to obtain a high-quality silicon oxide film (SiOx) using the plasma CVD method, a special gas-designated silane (SiH ₄ ) must be used, or the film formation temperature is high. Application to a polymer film substrate was difficult. A silicon oxide film formed by plasma CVD using an improved organosilane compound has been studied and put into practical use in the food packaging field (Non-Patent Document 1).
Novel Transparent Gas Barrier Film Prepared by PECVD Method, 43rd Annual Technical Conference Proceedings, Society of Vacuum Coater, 1, (2000), P.352

 However, even if the plasma CVD method as described above is used, if a dense film is to be obtained in order to aim at a high gas barrier property toward an organic EL or the like, it is necessary to form a film with higher density or high temperature. And the thermal load tends to increase. For this reason, a dense film cannot be obtained within the usable temperature range of the polymer film substrate, and adhesion, cracks, and the like are problematic because the difference in thermal expansion coefficient between the film and the inorganic oxide film is large.

 Therefore, the present invention proposes a vacuum film forming apparatus for producing a polymer film laminate having a high gas barrier property and an optimum method for producing a polymer film laminate.

A vacuum film forming apparatus of the present invention includes a film forming chamber for forming a thin film on a polymer film substrate by a plasma CVD method, a raw material jetting part for introducing a thin film raw material into the film forming chamber, an electrode for generating plasma, The electrode is capable of generating plasma by holocathode discharge, and an ejection hole for ejecting plasma by holocathode discharge is formed on the surface of the electrode. A magnetron for 400 gauss is provided.
Moreover, it is preferable that the hole diameter of the said ejection hole is 1 to 10 mm, and it is preferable to have a function for cooling a polymer film base material in addition.

  The method for producing a polymer film laminate of the present invention is a vacuum film formation method using the vacuum film formation apparatus, wherein oxygen is used for plasma ejection, a silane compound is introduced from a raw material ejection portion, and a polymer film substrate is produced. A film is formed on the material. Furthermore, it is preferable to form a film with the pressure in the film forming chamber set to 1 Pa or less.

  In the vacuum film formation method using the vacuum film formation apparatus, the polymer film laminate of the present invention uses oxygen for plasma injection, introduces a silane compound from a raw material injection part, and a silicon oxide film (SiOx) It is obtained by forming a film on a polymer film substrate. In addition, the silane compound is preferably an organosilane.

 According to the present invention, a high gas barrier capable of obtaining a dense film in the usable temperature range of the polymer film substrate, improving the adhesion between the film and the inorganic oxide film, and suppressing the occurrence of cracks and the like. A polymer film laminate having properties can be obtained.

 Hereinafter, an embodiment according to the present invention will be described. The vacuum film forming apparatus will be described in detail with reference to FIGS. 1 to 3, and the polymer film laminate produced using this vacuum film forming apparatus will be described in detail with reference to FIG.

  FIG. 1 is a cross-sectional view of a winding type vacuum film forming apparatus which is an example of an embodiment of the present invention. The winding-type vacuum film forming apparatus 10 has an unwinding / winding chamber 12 and a film forming chamber 14, and each of the unwinding / winding chamber 12 and the film forming chamber 14 is arbitrarily set by a vacuum pump (not shown). Adjustable to pressure. The unwinding / winding chamber 12 has a winding shaft 16 having a means capable of winding with a constant tension such as a torque motor, and a polymer film base while applying a constant back tension by a torque control means such as a powder clutch. An unwinding shaft 18 that enables unwinding of the material is provided. Also, a plurality of idle rolls 22 and 24 for restricting the travel of the sheet-like film 20 during the manufacturing process, tension rolls 26 and 28 having tension detectors for appropriately adjusting the tension, and the surface of the sheet-like film 20 Temperature sensors 30 and 32 are provided for monitoring the temperature. The film formation chamber 14 has a main roll 34 having a temperature adjusting mechanism for controlling the temperature of the film surface during film formation, an electrode 36 capable of generating plasma by a holocathode discharge, and a material introduction pipe 38 serving as a material ejection portion. Is provided. The raw material introduction pipe 38 is connected to a raw material supplier (not shown) installed outside the vacuum film forming apparatus 10.

  FIG. 2 is a cross-sectional view showing an example of the electrode 36. The electrode 36 includes an electrode body 40, a surface plate 42 that covers the surface portion of the electrode, a magnetron 44, and a magnetron cover 46 that covers the magnetron 44. A plurality of ejection holes 48 for ejecting plasma gas are formed in the surface plate 42. The electrode body 40 includes a gas introduction pipe 50 and a gas reservoir chamber 52 for drawing a discharge gas used for plasma ejection into the electrode body 40. The gas introduction tube 50 is connected to a discharge gas supply device (not shown) installed outside the vacuum film forming apparatus 10.

  The electrode body 40 is capable of holocathode discharge. In the electrode 36, not only the strong discharge is concentrated in the ejection hole 48 to stabilize the discharge, but also the strong discharge is concentrated in the vicinity of the electrode to suppress ion damage to the polymer film substrate. The temperature of the material can be kept low.

  FIG. 3 shows the electrode 36 as viewed from above. The arrangement of the magnetron 44 as viewed from the upper side of the surface plate 42 is such that the N pole 54 surrounds the center of the ejection holes 48 arranged in two rows at equal intervals, and the S pole 56 surrounds the outer periphery of the ejection holes 48. It is preferable that it is installed in the lower part. The arrangement of the N pole and the S pole can be the S pole at the center and the N pole at the outer periphery. By arranging such an N pole (or S pole) so that the S pole (or N pole) surrounds, the collision frequency of charged particles is increased using the E × B drift effect, and the film formation chamber is formed. Even at low pressure, it is easy to generate and maintain high-density plasma.

If the hole diameter is less than 1 mm, the plasma cannot enter the discharge hole and a holocathode discharge is difficult to be formed. Become stable. Therefore, the diameter of the ejection hole 48 is preferably 1 to 10 mm. Further, although the arrangement of the ejection holes 48 is not particularly defined, it is preferably arranged regularly in order to maintain the uniformity of the thin film thickness and film quality.
In addition, the main roll 34 preferably has a cooling mechanism in order to prevent the sheet-like film 20 serving as a base material from being heated to a high temperature by plasma and avoid deformation of the film.

  The present invention is not limited to the illustrated winding-type vacuum film forming apparatus, and is also implemented in a batch type apparatus that forms a film for each predetermined unit of a polymer film substrate and manufactures a polymer film laminate. Is possible.

Next, an example of a method for producing a polymer film laminate using the vacuum film forming apparatus 10 will be described. The roll-shaped polymer film substrate 58 installed on the unwinding shaft 18 is unwound and transferred as a sheet-like film 20. Thereafter, the film is transferred from the unwinding / winding chamber 12 to the film forming chamber 14 through the idle roll 22 while being wound around the main roll 34 set at an arbitrary temperature. The sheet-like film 20 is transferred again to the unwinding / winding chamber 12, and the sheet-like film 20 is wound as the roll-like polymer film laminate 60 on the winding shaft 16 through the idle roll. During this time, the sheet-like film 20 is maintained at a constant tension by the tension rolls 26 and 28.
While the sheet-like film 20 is being transferred, the film forming chamber 14 is decompressed by a vacuum pump (not shown) to be in a predetermined vacuum state. Thereafter, the film forming material gas selected from the material introducing pipe 38 is introduced into the film forming chamber 14. At this time, it is desirable that the source gas be emitted in the direction of the arrow shown in FIG. 2, that is, toward the plasma gas emitted from the electrode 36. The surface of the electrode 36 is set to 30 to 400 gauss by the magnetron 44. A gas for plasma ejection is taken into a gas reservoir chamber 52 through a gas introduction pipe 50 from a gas supply device (not shown) installed outside the vacuum film forming apparatus 10. Subsequently, the electrode main body 40 is operated, and plasma gas is ejected from the ejection holes 48 toward the main roll 34 from the ejection holes 48. The plasma gas reaches the sheet-like film 20 on the surface of the main roll 34 and forms a film while taking in the raw material gas ejected from the raw material introduction pipe 38.

  In the production method, the temperature of the polymer film substrate during production is not particularly limited, but it is desirable to cool in order to suppress the load on the polymer film due to high temperature. In addition, the pressure in the film forming chamber 14 of the vacuum film forming apparatus 10 is not particularly limited, but is preferably 1 Pa or less in order to suppress the reaction in the gas layer between the electrode 36 and the main roll 34 as much as possible. .

An inert gas such as argon can be used as the discharge gas for plasma ejection, but oxygen is used as the discharge gas in order to obtain a polymer film laminate having a silicon oxide film formed thereon. Moreover, the raw material of a thin film should just be selected suitably according to the kind of thin film to form into a polymer film base material, and there is no limitation in particular. For example, when a silicon oxide film is formed, a silane compound is used. As the silane compound, a highly reactive compound such as silane (SiH ₄ ) can be used, but a more general-purpose organic silane compound can be used. Examples of organic silane compounds include tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylsilane (TMS), hexamethyldisilazane, hexamethyldisiloxane (HMDSO), tetramethyldisiloxane, methyltrimethoxysilane It is also possible to select a silane compound having a relatively low molecular weight such as one or more of these silane compounds. Of these silane compounds, TEOS, TMOS, TMS, HMDSO and the like are preferable in view of the film forming pressure and the vapor pressure.

Next, an example of the polymer film laminate of the present invention will be described with reference to FIG. The polymer film laminate is composed of a polymer film substrate 62 and a silicon oxide film 64 formed. The polymer film substrate 62 of the polymer film laminate is preferably a film that takes advantage of the transparency of the barrier layer. For example, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate films (PC), polyether sulfone (PES), polycarbonate films, polyarylate films, polyolefin films such as polyethylene and polypropylene, cyclic cyclo A cycloolefin film containing olefin, a polystyrene film, a polyamide film, a polyvinyl chloride film, a polyacrylonitrile film, a polyimide film, or the like is used. The polymer film substrate 62 may be either stretched or unstretched, and more preferably has mechanical strength and dimensional stability. There is no problem even if the film is arbitrarily stretched in the biaxial direction. Various known additives and stabilizers may be used on the surface of the polymer film substrate. For example, an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, a lubricant and the like may be used. Furthermore, in order to improve the adhesion between the polymer film substrate 62 and the thin film, a primer layer may be provided, or corona treatment, low-temperature plasma treatment, ion bombardment treatment may be performed as pretreatment, and further chemical treatment. Further, a solvent treatment or the like may be performed.
The silicon oxide film 64 is formed using oxygen for plasma ejection, and the silicon oxide film 64 is provided using silane, preferably an organic silane compound, more preferably TEOS, TMOS, TMS, HMDSO, or the like as a thin film material. Moreover, using oxygen for plasma ejection has the effect of making the silicon oxide film 64 more transparent.
Although the thickness of the silicon oxide film is not particularly limited, it is considered that 10 nm or more is necessary because it is difficult to develop barrier properties if it is too thin. As a means for improving the barrier performance, a method of increasing the film thickness is conceivable, and the desired film thickness can be controlled in consideration of the flexibility and transparency of the manufactured polymer film laminate and the economic aspect. Here, if the film thickness is less than 50 nm, sufficient barrier properties suitable for organic EL cannot be obtained, and if the film thickness exceeds 1000 nm, the flexibility of the polymer film laminate is lost. Therefore, when adapting to organic EL, it is more preferable that the film thickness is 50 to 1000 nm.

  The film thickness can be controlled by changing the manufacturing speed or the number of electrodes in the case of a winding type like the vacuum film forming apparatus 10 illustrated here. It is also possible to increase the film thickness by performing the manufacturing once and then reversing again to repeat the same manufacturing process. On the other hand, in a batch-type apparatus for producing a polymer film laminate for each predetermined unit of the polymer film substrate, this is possible by controlling the film formation time.

  As described above, according to the vacuum film forming apparatus and the polymer film laminate manufacturing method of the present invention, a silicon oxide film (SiOx) can be formed on a polymer film substrate, and the barrier property is high. A molecular film laminate can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, it is not limited to an Example.

[Example 1]
Using a biaxially stretched polyethylene terephthalate (PET) film (Mitsubishi Polyester, Diafoil) having a thickness of 100 μm as a polymer film substrate, the unwinding shaft as a roll film in the winding type plasma CVD film forming apparatus shown in FIG. The film formation chamber was evacuated to 2.0 × 10 ⁻⁴ Pa. Next, the temperature of the main roll was set to −20 ° C., 50 sccm of oxygen was introduced into the electrode part, 5 sccm of HMDSO was introduced from the raw material introduction pipe, and the film formation chamber was set to 3.0 × 10 ⁻¹ Pa. Subsequently, a high frequency of 13.56 MHz was applied to the electrode at 0.5 kW to generate a holocathode discharge. Subsequently, a PET film as a polymer film substrate was run at 0.3 m / min to produce a polymer film laminate. The thickness of the obtained silicon oxide film was 50 nm.

[Example 2]
In the film forming chamber of the winding type plasma CVD film forming apparatus shown in FIG. 1, four electrodes capable of holocathode discharge are arranged on the main roll, and a raw material introduction pipe is installed on each of them. Next, the temperature of the main roll was set to −20 ° C., 50 sccm of oxygen was introduced to each electrode as a discharge gas, 5 sccm of HMDSO was introduced from the material introduction pipe, and the film formation chamber was set to 7.0 × 10 ⁻¹ Pa. Subsequently, a high frequency of 13.56 MHz was applied to the electrode at 0.75 kW to generate a holo cathode discharge. Subsequently, a PET film as a polymer film substrate was run at 0.5 m / min to produce a polymer film laminate. The thickness of the obtained silicon oxide film was 100 nm.

[Comparative Example 1]
A polymer film laminate was obtained under the same conditions as in Example 1 except that the film forming chamber was set to 5 Pa.

[Comparative Example 2]
A polymer film laminate was obtained under the same conditions as in Example 3 except that the film forming chamber was set to 5 Pa and the temperature of the main roll was set to 50 ° C.

The gas barrier properties of the polymer film laminates obtained in the above Examples and Comparative Examples were measured. The measurement was performed using a water vapor transmission rate measuring device (PERMATRAN-W3 / 33 manufactured by MOCON) under the conditions of 40 ° C. and relative humidity of 90%. The results are shown in Table 1. The barrier property of the PET film used for the polymer film substrate is 5.0 g / m ² / day.

From the results of Examples 1 and 2, when the vacuum film forming apparatus of the present invention is used, a polymer film laminate can be manufactured even when the film forming chamber is set to 1 Pa or less, and further manufactured under these conditions. It was confirmed that the polymer film laminate had good barrier properties. On the other hand, as shown in Comparative Example 1, it can be seen that when the pressure in the film forming chamber is 5 Pa, the barrier property is greatly deteriorated. Therefore, by producing the film forming chamber at 1 Pa or less, the temperature of the polymer film substrate can be lowered, and the thermal load on the polymer film substrate can be greatly reduced.
In order to increase the film thickness, it is conceivable to install a plurality of electrodes or increase the discharge pressure. From the results of Example 2 and Comparative Example 2, unless the film forming chamber is set to 1 Pa or less and the polymer film substrate is not maintained at a low temperature, the heat load on the polymer film substrate is increased. It was found that the polymer film laminate could not be produced due to the deformation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view showing an entire winding type vacuum film forming apparatus as an embodiment of the present invention. It is sectional drawing of the electrode which can perform the holo cathode discharge inside the winding-type vacuum film-forming apparatus which is the embodiment of this invention. It is explanatory drawing which looked at the electrode which can perform the holo cathode discharge concerning this invention from the upper part. It is explanatory drawing showing the side cross section of the permeable polymer film laminated body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Winding type vacuum film-forming apparatus 12 Unwinding and winding chamber 14 Film-forming chamber 16 Winding shaft 18 Unwinding shaft 20 Sheet-like films 22 and 24 Idle rolls 26 and 28 Tension rolls 30 and 32 Temperature sensor 34 Main roll 36 Electrode 38 Raw material introduction pipe 40 Electrode body 42 Surface plate 44 Magnetron 46 Magnetron cover 48 Ejection hole 50 Gas introduction pipe 52 Gas reservoir chamber 54 N pole 56 S pole 58 Rolled polymer film substrate 60 Rolled polymer film laminate 62 Polymer film substrate 64 Silicon oxide film

Claims (5)

In a vacuum film-forming apparatus used in a method for producing a polymer film laminate for forming a film on a polymer film substrate by a vacuum film-forming method, a film-forming chamber for forming a thin film on the polymer film substrate by a plasma CVD method; , a raw material ejection portion for introducing a silane compound as a raw material for thin film deposition chamber, possess an electrode for plasma generation, said electrodes to generate plasma by hollow cathode discharge, the surface of the electrode is hollow cathode discharge A vacuum film-forming apparatus, characterized in that an ejection hole for ejecting plasma by oxygen with oxygen is formed, and a magnetron is provided to make the electrode surface 30 to 400 gauss.   The vacuum film-forming apparatus according to claim 1, wherein the diameter of the ejection hole on the electrode surface is 1 to 10 mm.   The vacuum film forming apparatus according to claim 1, further comprising a cooling mechanism for cooling the polymer film substrate. The method of manufacturing a polymer film laminate, characterized in that there use a vacuum deposition apparatus according to any one of claims 1 to 3.   The method for producing a polymer film laminate according to claim 4, wherein the film forming chamber is formed with a pressure of 1 Pa or less.

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