JP2008068460A - Transparent polyester film for vapor deposition and transparent vapor deposition polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent polyester film for vapor deposition which enables the stable production of a transparent vapor deposition polyester film indicating high gas-barrier properties by a thin vapor deposition film. <P>SOLUTION: The transparent polyester film for vapor deposition meets the following five characteristics simultaneously: (1) the polyester film is composed of at least two layers of a layer A and a layer B, (2) the layer A contains no particle, while the layer B contains particles of number average particle size 1-6 μm, (3) when the surface roughness of the layer A is ARa and the surface roughness of the layer B is BRa, ARa<BRa and ARa≤0.02 μm, (4) the thickness of the later A is 0.05-10 times as large as the number average particle size of the particles contained in the layer B, and (5) the thermal shrinkage factor in the width direction at 190°C and for 20 min of the polyester film is 0.0-5.0%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a transparent vapor-deposited polyester film excellent in oxygen and water vapor barrier properties (gas barrier properties), and a transparent vapor-deposited polyester film suitable for that purpose.

  In order to store foods and medicines for a long period of time, it is necessary to package them with a packaging material that has the effect of blocking the entry of oxygen and water vapor from the outside in order to prevent their decay and deterioration. As a film wrapping material having excellent gas barrier properties used for this purpose, a film in which polyvinylidene chloride or ethylene vinyl alcohol copolymer is laminated is known, but the barrier property against oxygen / water vapor is not sufficient, and Especially, the barrier property is remarkably lowered during sterilization treatment at high temperature. In addition, polyvinylidene chloride generates chlorine-based gas during incineration, and it has been pointed out that corrosion of the incinerator and adverse effects on the global environment have been pointed out, and that the burden on the incinerator for purifying exhaust gas is also large. .

On the other hand, since a polyester film in which a metal film such as aluminum is formed by vapor deposition exhibits good gas barrier properties, a vapor deposited film in which a silicon oxide or aluminum oxide film is formed is often used. In recent years, a transparent vapor deposition film on which a silicon oxide or aluminum oxide film is formed is often used because of excellent visibility for confirming the state of the contents. In recent years, demands for improving the quality of these vapor-deposited films and for further improving the gas barrier properties in order to enhance the long-term storage stability of the contents have become stronger.
As the polyester film for the above purpose, for example, when the surface roughness of the surface A surface of the A layer is ARa, and the surface roughness of the surface B surface of the B layer is BRa, ARa <BRa, ARa ≦ 0.05 μm, A polyester film (see Patent Document 1) that satisfies 0.02 ≦ BRa ≦ 0.3 μm has been proposed.

Such a polyester film provides a polyester film with improved runnability during vapor deposition and excellent gas barrier properties by making the surface A surface of the A layer and the surface B surface of the B layer into desired surface forms. can do.
Further, at least one sublayer contains inert particles, the average particle diameter of the inert particles is 0.1 to 10 times the thickness of the sublayer, and the content of the particles is relative to the polyester resin of the sublayer. In addition, a polyester film for vapor deposition (see Patent Document 2), which is 0.01 to 5% by weight, has also been proposed.
Such a polyester film can improve the runnability at the time of vapor deposition by making the surface of a sublayer into a desired surface form by containing an inert particle in a sublayer.
JP-A-11-129423 (Claims) Japanese Patent Laying-Open No. 2003-200546 (Claims)

However, these polyester films have a problem that since the metal vapor-deposited film is brittle, the stability of the gas barrier is poor, and industrial production of the vapor-deposited film having good gas barrier properties is not easy and stable production is difficult. These problems are particularly prominent in a transparent deposited film on which a silicon oxide or aluminum oxide film is formed, and a film that can solve these problems has been desired.

  Therefore, the present invention provides a polyester film for transparent vapor deposition that solves the above-described problems and can stably produce a transparent vapor-deposited polyester film that exhibits high gas barrier properties even with a thin vapor deposition film. Furthermore, an object of the present invention is to provide a transparent vapor-deposited polyester film having excellent gas barrier properties.

The polyester film for transparent vapor deposition of the present invention is,
1. A polyester film for transparent vapor deposition that simultaneously satisfies the following characteristics (1) to (5):
(1) The polyester film is composed of at least two layers of an A layer and a B layer. (2) The A layer is a substantially particle-free layer, and only the B layer contains particles having a number average particle diameter of 1 to 6 μm ( 3) When the surface roughness of the surface A surface of the A layer is ARa and the surface roughness of the surface B surface of the B layer is BRa, ARa <BRa and ARa ≦ 0.02 μm
(4) The layer thickness of the A layer is 0.05 times to 10 times the average particle size of the particles contained in the B layer. (5) The thermal shrinkage rate at 190 ° C. for 20 minutes in the width direction is 0.0% to 5. 0%
2. 1. A layer surface is a surface for forming a deposited film. The polyester film for transparent vapor deposition according to
3.1. Or 2. A transparent vapor-deposited polyester film comprising a vapor-deposited film on the surface for vapor-deposited film formation of the transparent vapor-deposited polyester film,
4). 2. The deposited film contains at least one of aluminum oxide and silicon oxide. Transparent vapor-deposited polyester film,
It is.

According to the polyester film for transparent vapor deposition of the present invention, it becomes possible to stably produce a transparent vapor-deposited polyester film exhibiting a high gas barrier property even with a thin vapor-deposited film. It becomes possible to provide a vapor-deposited polyester film.

  In the polyester film for transparent vapor deposition of the present invention, the surface A surface of the A layer and the surface B surface of the B layer can be easily obtained by forming a laminated film of at least two layers of the A layer and the B layer. It can be in surface form.

  By making the A layer a non-particle layer and making the surface roughness of the surface A surface of the A layer a relatively flat surface having a specific value or less, the adhesion with the vapor deposition layer is improved, and the transparent vapor deposition layer of the thin film Even if it exists, a desired layer form can be maintained easily and favorable gas barrier property is exhibited.

The term “particle-free layer” as used herein refers to a case where the weight of the particles contained in the A layer or the B layer is 0.001% by weight or less with respect to the film weight of the A layer or the B layer.
In addition, the layer B contains particles having a number average particle diameter of 1 to 6 μm and has a surface in a specific range having a relatively large surface roughness, thereby reducing the coefficient of friction and improving running performance and handling performance. The processability when making a gas barrier film can be kept good.

The surface roughness ARa of the surface A surface of the A layer and the surface roughness BRa of the surface B surface of the B layer must satisfy the following conditions.
ARa <BRa and ARa ≦ 0.02 μm
ARa <BRa, that is, if the surface roughness of the surface A surface of the A layer is not smaller than the surface roughness of the surface B surface of the B layer, the surface A layer of the A layer is not suitable for vapor deposition, and a dense vapor deposition film The problem of not being formed arises. Further, if the surface roughness of the surface B surface of the B layer is not larger than the surface roughness of the surface A surface of the A layer, there arises a problem that handling properties are deteriorated and traveling properties are deteriorated.
Furthermore, if the surface roughness of the surface A surface of the A layer is not 0.02 μm or less, the surface A layer of the A layer is not suitable for vapor deposition and a dense vapor deposition film is not formed.

  The layer thickness of the A layer needs to be 0.05 to 10 times the average particle size of the particles contained in the B layer, and preferably 0.1 to 10 times. If it is less than 0.05 times, the gas barrier properties deteriorate, and if it exceeds 10 times, the film surface becomes smooth and the running properties of the film deteriorate.

  The particles contained in the B layer preferably contain particles inert to the polyester. The inert particles are not particularly limited as long as they are inert to the polyester, but are particles arbitrarily selected from external particles such as internal particles, inorganic particles, and / or organic particles. Examples of the inorganic particles and / or organic particles include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay and the like, styrene, and silicone. And organic particles containing acrylic acid as a constituent component. Of these, inorganic particles such as wet and dry silica, colloidal silica, aluminum silicate, alumina and calcium carbonate are preferred. These internal particles, inorganic particles and / or organic particles may be used in combination of two or more. The number average particle diameter of the particles measured by the sedimentation method or the light scattering method needs to be 1 to 6 μm, and preferably 2.0 to 5.0 μm. When the thickness is less than 1 μm, the film surface of the B layer becomes smooth, and the running property of the film deteriorates or causes blocking. On the other hand, if it exceeds 6 μm, the transparency of the film deteriorates or the gas barrier property deteriorates.

  The content of the particles is preferably 0.01 to 1.0% by weight, more preferably 0.1 to 1.0% by weight, based on the polyester resin of the B layer. When the content of the particles is less than 0.01% by weight, the surface becomes smooth and the running property of the film may deteriorate. On the other hand, if it exceeds 1.0% by weight, the transparency of the film may deteriorate, or the gas barrier property may deteriorate.

  The heat shrinkage rate at 190 ° C. for 20 minutes in the width direction of the polyester film for transparent vapor deposition of the present invention needs to be 0.0% to 5.0%, preferably 3.0 to 5.0%. is there. If the heat shrinkage rate in the width direction at 190 ° C. for 20 minutes is within this range, when the vapor deposition layer is vapor deposited, the film shrinks due to the heat during vapor deposition processing, thereby forming a dense vapor deposition film of vapor deposition molecules. The gas barrier performance of the film is increased. However, if the thermal shrinkage rate at 190 ° C in the width direction at 20 minutes exceeds 5.0%, the film shrinks excessively, wrinkles occur in the film, or the running property of the film becomes unstable and is produced. The problem arises that the speed cannot be increased. In addition, when the thermal shrinkage rate at 190 ° C. in the width direction at 20 minutes is less than 0.0%, that is, when the film is stretched, a dense vapor deposition film is not formed, and the gas barrier performance of the polyester film after vapor deposition is lowered. Problem arises.

A polyester film that satisfies the above conditions and whose surface of layer A is a surface for forming a vapor deposition film is suitable as a polyester film for transparent vapor deposition.
This is because the surface of the A layer of the polyester film of the present invention is suitable for vapor deposition, and the surface of the B layer is suitable for stabilizing handling properties and running properties.

  In addition, by setting the heat-absorbing stress within a specific range, when vapor deposition is performed, a dense vapor-deposited film is formed and the running property of the film is stabilized.

  In addition, the A layer and the B layer of the present invention include known additives, for example, a heat resistance stabilizer, an oxidation resistance stabilizer, a weather resistance stabilizer, an ultraviolet absorber, an organic lubricant, as long as the effects of the present invention are not impaired. Pigments, dyes, organic or inorganic fine particles, fillers, nucleating agents, and the like may be blended.

  Furthermore, the film of the present invention may be subjected to various coatings, and is not particularly limited. However, in consideration of production and environmental aspects, a film in which an aqueous or water-dispersed coating agent is applied during film formation is preferable.

The thickness of the polyester film of the present invention is preferably 5 to 80 μm, and more preferably 10 to 50 μm. Among these, a suitable range may be arbitrarily selected depending on the application.
The surface of the film of the present invention may be subjected to a known surface treatment, that is, a low-temperature plasma treatment or a corona discharge treatment.

  As the polyester-based resin constituting the polyester film of the present invention, those having ethylene terephthalate and / or ethylene naphthalate units as main constituent components are preferable from the viewpoint of ester bonds, and from the viewpoint of heat resistance and film-forming properties, polyesters are preferred. The melting point is preferably 250 ° C. or higher and 280 ° C. or lower.

  As this polyester-based resin, various polyesters obtained by ester-linking an acid component and a glycol component can be used in addition to the above preferred polyester. Examples of acid components in this case include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid, and cyclohexanedicarboxylic acid. And polyfunctional acids such as trimellitic acid and pyromellitic acid can be used. On the other hand, examples of the glycol component include aliphatic diols such as ethylene glycol, diethylene glycol, butanediol, and hexanediol, alicyclic diols such as cyclohexanedimethanol, aromatic glycols such as bisphenol A and bisphenol S, diethylene glycol, and polyalkylene glycols. Etc. can be used. Furthermore, polyethers such as polyethylene glycol and polytetramethylene glycol may be copolymerized. In addition, these dicarboxylic acid component and glycol component may use 2 or more types together, and may blend and use 2 or more types of polyester.

  The intrinsic viscosity of the polymer is not particularly limited, but is desirably in the range of 0.6 to 1.8 dl / g. Furthermore, the film of the present invention may be subjected to various coatings and is not particularly limited. However, in view of production and environmental aspects, a film obtained by applying an aqueous or water-dispersed coating agent to a film is preferable. The polyester film of the present invention is preferably biaxially stretched. A biaxially stretched polyester film is made by stretching a non-stretched polyester sheet or film in a so-called biaxial direction in the longitudinal direction and width direction, and forms a biaxially oriented pattern by wide-angle X-ray diffraction. Say what you indicate. The biaxial stretching method may be either sequential biaxial stretching or simultaneous biaxial stretching, but simultaneous biaxial stretching is preferable because scratches are not easily generated on the film surface.

  Examples of the deposited film provided on the polyester film of the present invention include at least aluminum, a silicon oxide film, a metal typified by aluminum oxide, and a metal oxide. Although the thickness of a vapor deposition film is not specifically limited, 5-150 nm is suitable from productivity, handling property, and external appearance. Next, although the manufacturing method of the polyester film which concerns on this invention is demonstrated, it is not limited to this example. The dried polymer chip is supplied to an extruder, heated to a temperature equal to or higher than the melting point of the polymer, and melted. Next, the molten polymer is merged according to the laminated structure, and then extruded from a T-die having a slit-like discharge port, and is firmly adhered to a cooling roll to obtain a cast film. In order to improve the adhesion between the molten sheet and the cooling roll, it is usually preferable to employ an electrostatic application adhesion method and / or a liquid surface application adhesion method. The cast film is further stretched biaxially. Preferably, it is stretched 2.3 to 7 times in the longitudinal direction (longitudinal direction) with a group of rolls heated to a glass transition temperature of the polymer or higher, for example, 40 to 130 ° C., and then preferably 45 to 130 in the width direction (transverse direction). Stretch 3 to 7 times at ° C. In addition, although the method of extending | stretching one direction in two steps or more can be used, it is preferable that the final draw ratio also falls in the said range also in that case. The cast film can be simultaneously biaxially stretched so that the area magnification is 6 to 30 times.

  The film thus obtained is heat-treated, and may be stretched again in the longitudinal and / or transverse direction before or after the heat treatment, if necessary. The heat treatment temperature is 150 to 250 ° C., preferably 200 to 240 ° C., and the heat treatment time is usually 1 second to 5 minutes. The heat shrinkage characteristics can be adjusted under these heat treatment conditions. In addition, the cooling rate of the film after heat treatment also affects the heat shrink characteristics. For example, after the heat treatment, the heat shrinkage stress can be adjusted by providing the film with rapid cooling or slow cooling, or by providing an intermediate cooling zone. Moreover, in order to give a specific heat shrink characteristic, you may relax in the vertical direction and / or the horizontal direction during the heat treatment or in the subsequent slow cooling zone.

The film can be coated as necessary. In the case of the present invention, by providing the coating layer on the film, it is possible to particularly improve the adhesion to the vapor deposition layer and the ink layer. As the coating solution, a solution which is dissolved in water, emulsified or suspended in view of explosion proof and environmental pollution is used. The coating layer may be applied to a biaxially stretched film after completion of crystal orientation, or may be stretched after being applied to a film before completion of crystal orientation, but the latter method is used in order to exhibit the effects of the present invention more remarkably. Is particularly preferred. The method of applying is not particularly limited, but it is preferable to apply using a roll coater, gravure coater, reverse coater, kiss coater, bar coater or the like. Moreover, you may corona-discharge-process in the air | atmosphere other various atmosphere before application | coating as needed before apply | coating.
In the coating layer in the present invention, an antifoaming agent, a coating crosslinker, a thickener, an organic lubricant, inorganic particles, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, and a pigment are used as necessary. Etc. may be included.

A vapor-deposited layer is provided on the biaxially oriented polyester film thus obtained. A vacuum process is used to provide a deposited metal film. Typical examples of the vacuum process include a vacuum deposition method, a sputtering method, and an ion plating method. A preferable method includes a vacuum deposition method.
A vacuum process is used to provide a deposited metal oxide film. As the vacuum process, a vacuum deposition method, a sputtering method, an ion plating method, a chemical vapor deposition method, or the like is appropriately used, and any of them is not limited, but the reactive deposition method is preferably used in terms of productivity and cost. it can. To deposit aluminum oxide in reactive vapor deposition, aluminum metal and alumina are evaporated by resistance heating boat method, crucible high frequency induction heating, electron beam heating method, and oxidized on biaxially oriented polyester film in an oxidizing atmosphere. A method of depositing aluminum is adopted. As a reactive gas for forming an oxidizing atmosphere, water or a rare gas may be added mainly with oxygen. Furthermore, a method of promoting a reaction such as adding ozone or ion assist may be employed. When the plasma treatment of the biaxially oriented polyester film surface in these vacuum processes is used in combination, gas barrier properties and moisture permeability are improved, which is more preferable. In order to deposit silicon oxide by the reactive deposition method, a method is employed in which Si metal, SiO or SiO ₂ is evaporated by an electron beam heating method, and silicon oxide is deposited on a biaxially oriented polyester film in an oxidizing atmosphere. . The method described above is used as a method of forming the oxidizing atmosphere.
<Measurement method of physical properties and evaluation method of effect>
(1) Surface roughness The centerline average roughness was measured according to JIS-B-0601-2001.

(2) Average particle size
The thermoplastic resin is removed from the surface of the film by a plasma low-temperature ashing treatment method to expose the particles. The processing conditions are selected so that the thermoplastic resin is ashed but the particles are not damaged. This is observed with a scanning electron microscope (SEM), and the image of the particles is processed with an image analyzer. The number average diameter D obtained by carrying out the following numerical processing on the number of particles of 5000 or more by changing the observation location is defined as the average particle diameter.
D = ΣDi / N
Here, Di is the equivalent circle diameter of the particles, and N is the number of particles.

(3) Heat shrinkage rate of the film sample marked line is set to 200 mm, the film is cut to 10 mm, the film sample is suspended in the length direction, a 1 g load is applied in the length direction, and the hot air oven is set to a predetermined temperature in advance. After heating for a predetermined time, the length between the marked lines was measured, and the amount of shrinkage of the film was expressed as a percentage with respect to the original dimension.
In addition, the thing which the film extended | stretched displayed minus (-).

(4) Intrinsic viscosity
The value calculated from the following equation from the solution viscosity measured at 25 ° C. in orthochlorophenol was used. ηsp / C = [η] + K [η] 2 · C
Here, ηsp = (solution viscosity / solvent viscosity) -1C: weight of dissolved polymer per 100 ml of solvent (g / 100 ml)
K: Huggins constant (0.343)
The solution viscosity and the solvent viscosity were measured with an Ostwald viscometer.

(5) Gas barrier properties of the deposited film Water Vapor Permeability 48 hours after vapor deposition, measurement was performed under the conditions of 40 ° C. and 90 RH% according to the method B described in JIS-K-7129-1992 using a modern water vapor permeability meter PERMATRAN-W1A. It evaluated as follows by the measured water-vapor-permeation rate.
A: 0 (g / m ² · day) or more, less than 2.0 (g / m ² · day)
○: 2.0 (g / m ² · day) or more and less than 3.0 (g / m ² · day)
X: 3.0 (g / m ² · day) or more.
B. Oxygen permeability 48 hours after deposition, oxygen permeation was performed under the conditions of 20 ° C. and 0% RH according to the method B described in JIS-K-7126-1987 using an oxygen permeability measuring device OX-TRAN100 manufactured by Modern Control. The rate was measured. The following evaluation was made based on the measured oxygen permeability.
◎: 0 (cc / m ² · day) or more, less than 2.0 (cc / m ² · day)
○: 2.0 (cc / m ² · day) or more, less than 3.0 (cc / m ² · day)
X: 3.0 (cc / m ² · day) or more.

  Next, the present invention will be described based on examples, but is not necessarily limited thereto.

Example 1
Polyester A is polyethylene terephthalate (inherent viscosity 0.62 dl / g), and polyester B is polyethylene terephthalate (inherent viscosity 0.62 dl / g) containing 1.0% by weight of silicon dioxide particles having an average particle size of about 3.5 μm. After vacuum drying to a moisture content of 20 ppm, each is supplied to a separate extruder, melted at 280 ° C., and the polymer is merged into two layers of A / B, and then formed into a sheet from the T-shaped die. This was extruded and cooled and solidified on a cooling drum having a surface temperature of 25 ° C. by an electrostatic contact method. The unstretched film thus obtained was heated to 90 ° C., stretched 3.6 times in the longitudinal direction at 105 ° C., and then stretched 4.0 times in the width direction while heating to 108 ° C. The film was introduced into hot air at 225 ° C., subjected to a tension heat treatment for 3 seconds, and then cooled by 5% relaxation of the original film width in the lateral direction within the same atmospheric temperature. After finally cooling to room temperature, the surface of the polyester B layer side was subjected to corona discharge treatment at a treatment strength of 20 W · min / m ² , and this was guided to a winder and wound up to obtain a mill roll. The film thickness was 1.7 μm for the A layer and 10.3 μm for the B layer, for a total of 12 μm. Aluminum oxide vapor deposition was performed on the A layer side of the film thus obtained. In the method of depositing aluminum oxide on the surface of the biaxially oriented polyester film, the film is set on a winding device of a continuous vacuum vapor deposition machine, travels through a cooling metal drum, and is wound up. At this time, the pressure of the continuous vacuum evaporator is reduced to 10 ⁻⁴ Torr or less, and the aluminum crucible is charged into the alumina crucible from the lower part of the cooling drum to heat and evaporate the metal aluminum, and oxygen is contained in the vapor. Was deposited and deposited on the film while oxidizing to form an aluminum oxide film having a thickness of 30 nm.

Example 2
In Example 1, silicon oxide was used for vapor deposition on the film A layer.

Example 3
In Example 1, the average particle diameter of silicon dioxide particles in polyester B was 2.0 μm.

Example 4
In Example 1, the average particle diameter of silicon dioxide particles in polyester B was 5.0 μm.

Example 5
In Example 1, the content of silicon dioxide particles in polyester B was 0.1% by weight.

Example 6
In Example 1, the content of silicon dioxide particles in polyester B was 0.001% by weight.

Example 7
In Example 1, the layer thickness of the A layer was set to 0.1 times the average particle diameter of the particles contained in the B layer. The stacking ratio of the A layer and the B layer was 0.35 μm / 10.3 μm.

Example 8
In Example 1, the layer thickness of the A layer was set to 10 times the average particle diameter of the particles contained in the B layer. The stacking ratio of the A layer and the B layer was 35.0 / 10.3.

Example 9
In Example 1, the relaxation in the width direction was changed to 7%.

Comparative Example 1
In Example 1, 1.0% by weight of silicon dioxide particles having an average particle diameter of 1.0 μm was contained in polyester A.
The obtained film had poor gas barrier properties.

Comparative Example 2
In Example 1, 1.0% by weight of silicon dioxide particles having an average particle size of 3.5 μm was contained in the polyester A, and the polyester B layer was a non-particle layer.
The obtained film was wrinkled during winding, and the running performance deteriorated. Further, the gas barrier property was not good.

Comparative Example 3
In Example 1, the average particle diameter of silicon dioxide particles in polyester B was 0.5 μm.
The obtained film was wrinkled during winding, and the running performance deteriorated.

Comparative Example 4
In Example 1, the average particle diameter of silicon dioxide particles in polyester B was 8.0 μm.
The obtained film had poor transparency, and in the processing step, the adhesion that seemed to drop off the particles in the film was seen in the shape of a processing roll, and the gas barrier property was not good.

Comparative Example 5
In Example 1, the content of silicon dioxide particles in polyester B was 1.5% by weight.
The obtained film had poor transparency and gas barrier properties.

Comparative Example 6
In Example 1, the layer thickness of the A layer was 0.03 times the average particle diameter of the particles contained in the B layer. The lamination ratio of the A layer and the B layer was 0.1 μm / 10.3 μm.
The obtained film had poor gas barrier properties.

Comparative Example 7
In Example 1, the layer thickness of the A layer was 12.0 times the average particle size of the particles contained in the B layer. The stacking ratio of the A layer and the B layer was 42.0 / 10.3.
The obtained film was wrinkled during winding, and the running performance deteriorated.

Comparative Example 8
In Example 1, the relaxation in the width direction was changed to 3%.
The obtained film was wrinkled during vapor deposition and the running property was deteriorated.

Comparative Example 9
In Example 1, the relaxation in the width direction was changed to 10%.
The obtained film had poor gas barrier properties.

Claims (4)

The polyester film for transparent vapor deposition which satisfy | fills the characteristic of following (1)-(5) simultaneously.
(1) The polyester film is composed of at least two layers of an A layer and a B layer.
(2) The A layer is a non-particle layer, and the B layer contains particles having a number average particle diameter of 1 to 6 μm.
(3) When the surface roughness of the surface A surface of the A layer is ARa and the surface roughness of the surface B surface of the B layer is BRa, ARa <BRa and ARa ≦ 0.02 μm.
(4) The layer thickness of the A layer is 0.05 to 10 times the number average particle size of the particles contained in the B layer.
(5) 190 degreeC in the width direction and the heat shrinkage rate for 20 minutes are 0.0% to 5.0%. The polyester film for transparent vapor deposition according to claim 1, wherein the surface of the A layer is a vapor deposition film forming surface. The transparent vapor deposition polyester film which provides a vapor deposition film in the surface side for vapor deposition film formation of the polyester film for transparent vapor deposition of Claim 1 or 2. The transparent vapor-deposited polyester film according to claim 3, wherein the vapor-deposited film contains at least either aluminum oxide or silicon oxide.