JP2004155188A - Laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film having a high scattering prevention ability useful for protection of a glass, particularly a glass for a building material, a car, a flat display and the like. <P>SOLUTION: The laminated film is composed of at least five layers at least one surface of which has an adhesive layer having 4 N/10mm width or more of an adhesive force to a glass, and the laminated film has a tear strength of 50 N/mm or more. <P>COPYRIGHT: (C)2004,JPO

Description

   The present invention relates to a laminated film. More specifically, the present invention relates to a glass protective film suitable for protection of display glasses such as CRT displays, liquid crystal displays, plasma displays, organic EL displays, and field emission displays, window glasses for building materials, and window glasses for vehicles.

  Glass is used for various applications because of its excellent light transmittance, gas barrier properties, dimensional characteristics, and the like. In particular, in the field of flat displays represented by CRT displays, liquid crystal displays, plasma displays, organic EL displays, field emission displays, and the like, higher performance glasses are provided. However, in these applications, there is a tendency that the thickness of the display glass itself tends to be reduced due to a demand for a thinner flat display, and accordingly, there is a problem that the display glass is easily broken during use.

Various methods have been proposed for preventing such a problem of glass breakage and glass scattering caused by breakage by attaching a film made of a thermoplastic resin to glass. For example, by attaching a multilayer laminated film composed of a rigid layer and a ductile layer to the glass surface, breakage and scattering of the glass can be largely prevented (see Patent Documents 1 and 2).
JP-A-6-1990995 (page 2) JP-A-6-1990997 (page 2)

  However, the method described in the above-mentioned patent document cannot be used for a window glass for a high-grade building material or a protective film for a flat display, which requires higher scattering prevention performance and penetration resistance. Further, the ductile layer constituting the multilayer laminated film is gradually crystallized and whitened, causing a phenomenon of increasing the haze. Further, in order to actually obtain higher scattering prevention performance and penetration resistance, there is a case where improvement of the tear resistance of the film serving as the support alone is insufficient.

  An object of the present invention is to solve such a problem and to provide a laminated film suitable for protecting glass, particularly for protecting display glass such as flat displays, window glass for building materials, and window glass for vehicles.

  In order to solve the above problems, the glass protective film of the present invention has the following configuration.

  That is, it is a laminated film composed of at least five or more layers, and has an adhesive layer having an adhesive strength of 4N / 10 mm or more in adhesive strength to glass on at least one surface, and a tear strength of 50 N / mm or more. A laminated film characterized by the above-mentioned.

  Since the laminated film of the present invention has an adhesive layer having an adhesive strength of 4 N / 10 mm or more in adhesive strength to glass and a tear strength of 50 N / mm or more, it aims at preventing breakage and scattering of glass. It is possible to provide a laminated film having both of the above-mentioned tear resistance and impact resistance and the visibility when affixed to glass. In particular, it is possible to provide a glass protective film suitable as a protective film for display glass such as window glass for building materials, window glass for vehicles, and flat displays.

  Hereinafter, embodiments of the present invention will be described in detail.

  The present invention is a laminated film composed of at least 5 layers or more, having an adhesive layer having an adhesive strength of 4 N / 10 mm or more in adhesive strength with glass on at least one surface, and having a tear strength of 50 N / mm. It must be a laminated film characterized by the above.

  With the laminated film of the present invention, it is possible to prevent the scattering of higher performance glass, which cannot be achieved by the conventional technology. As a result of the inventor's diligent efforts, in order to attach a film having a high tear strength to glass and exhibit an unprecedented scattering prevention performance, the adhesive strength between the adhesive layer and the glass must be 4 N / 10 mm width or more. I found what I had to do. More preferably, the adhesive strength is 8 N / 10 mm width or more, and still more preferably 12 N / 10 mm width or more and 100 N / 10 mm width or less. When the adhesive strength of the pressure-sensitive adhesive layer is less than 4 N / mm, even if the laminated film itself is not severely torn, delamination with glass proceeds due to insufficient adhesive strength between the laminated film and glass, so that the scattering prevention performance is sufficient. Not. On the other hand, if the width is larger than 100 N / 10 mm, peeling is induced inside the film, which may not be preferable. In order to have such a high adhesive strength, it is particularly important to improve the adhesiveness of the film with the adhesive layer, and particularly when the easy adhesive layer is interposed between the film and the adhesive layer, a high adhesive strength is required. Obtainable. Further, when there is no easy-adhesion layer, an adhesive layer having higher adhesive strength may not be formed, which is not preferable.

  The glass protective film of the present invention must be composed of at least five or more layers. Preferably, it has at least 10 layers, more preferably at least 20 layers. If the number of layers is less than 5, it is not preferable because sufficient tear resistance and impact resistance cannot be obtained.

  The upper limit of the number of layers is not particularly limited, and may be, for example, about several hundred layers, but is preferably about 600 layers or 1,000 layers from the viewpoint of production. For this reason, the preferable range of the number of layers is 20 to 1000 layers, more preferably 50 to 600 layers.

  The laminated film of the present invention must have a tear strength of 50 N / mm or more. It is more preferably 80 N / mm or more, and further preferably 100 N / mm or more and 500 N / mm or less. When the tear strength is lower than 50 N / mm, it is difficult to obtain high scattering prevention performance because the tear easily propagates at the time of breaking. On the other hand, if it is less than 500 N / mm, stress is concentrated on portions other than the film, and local destruction may occur, which is not preferable. In this case, the tear strength of the film must be 50 N / mm or more in at least one direction. More preferably, the tear strength in the machine direction and the width direction of the film is 50 N / mm or more.

  In the laminated film of the present invention, it is preferable that five or more layers composed mainly of polyester and layers composed mainly of copolymerized polyester are alternately laminated in the thickness direction. As a preferred embodiment of the present invention, a film in which five or more layers are alternately laminated in the thickness direction is a film having a total of six or more layers having an adhesive layer on at least one side. When the layer mainly composed of polyester and the layer mainly composed of copolymerized polyester are alternately laminated in this way, the stress is appropriately dispersed at the time of breaking, and the tear strength can be greatly increased. Become.

  Here, the thickness of the polyester layer is preferably 1 μm or more and 30 μm or less. The thickness of the copolymerized polyester layer is preferably from 0.02 μm to 10 μm. In the case of such a configuration, it is possible to obtain a film having the highest tear strength and impact strength.

  The layer constituting the laminated film of the present invention is preferably made of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyamide resins such as nylon 6 and nylon 66; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate; Polycarbonate resin, polyarylate resin, polyacetal resin, polyphenylene sulfide resin, acrylic resin, and the like can be used. Among them, polyester is particularly preferable from the viewpoints of strength, heat resistance, and transparency. Further, among the polyester resins, polyethylene-2,6-naphthalate and polyethylene terephthalate are preferable, and polyethylene terephthalate is particularly preferable.

  Further, the polyester in the present invention includes a polyester resin which is a polycondensate of a dicarboxylic acid component skeleton and a diol component skeleton, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4 -Cyclohexane dimethylene terephthalate and the like can be used. In particular, since polyethylene terephthalate is inexpensive, it can be used in a wide variety of applications, and is highly effective.

  Further, the copolyester in the present invention is defined as a polycondensate comprising at least three or more components selected from the following dicarboxylic acid component skeleton and diol component skeleton. As the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene acid, 1,5-naphthalene acid, 2,6-naphthalene acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyl Sulfondicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid, and the like. As glycol components, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 2,2-bis (4′-β-hydroxyethoxy) Phenyl) propane, 1,4-cyclohexanedimethanol and the like.

  In the present invention, in particular, a layer mainly composed of polyethylene terephthalate or polyethylene naphthalate and a layer mainly composed of a copolymerized polyester having 1,4-cyclohexanedimethanol as a component are alternately laminated in the thickness direction. Is preferred. More preferably, a layer mainly composed of polyethylene terephthalate and a layer mainly composed of copolyester containing 1,4-cyclohexanedimethanol are alternately laminated in the thickness direction. More preferably, a layer mainly composed of polyethylene terephthalate and a layer mainly composed of polyethylene terephthalate copolymerized with 1,4-cyclohexanedimethanol of 15 mol% or more and 45 mol% or less are alternately laminated in the thickness direction. ing. In such a configuration, the tear resistance, impact resistance, and high transparency, which are the objects of the present invention, can be efficiently and simultaneously achieved. In the case of such a layer containing a polyester containing 1,4-cyclohexanedimethanol as a component, the polyester containing 1,4-cyclohexanedimethanol as a component is rigid and excellent in shock absorption. Therefore, the propagation of the cracks transmitted by the impact is suppressed by the layer containing the polyester containing 1,4-cyclohexanedimethanol as a component, so that the tear resistance and the impact resistance can be improved. Further, the layer containing a polyester containing 1,4-cyclohexanedimethanol as a component is excellent in transparency, and has almost no change with time at normal temperature and hardly whitens, so that visibility is excellent.

  Further, the polyester or copolymerized polyester of the present invention preferably has a tensile modulus of 1400 MPa or more. More preferably, it is 1600 MPa or more. The laminated film made of such a polyester is excellent in transparency, and has high penetration resistance and anti-scattering property at the time of high-speed breakage in which the high adhesive force of the present invention acts. This is because, when the polyester layer or the copolymerized polyester layer constituting the laminated film has a tensile modulus of elasticity of less than 1400 MPa, the laminated film is greatly deformed, so that the glass tends to fall off.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the laminated film of the present invention, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a cross-linked acrylic pressure-sensitive adhesive, a vinyl-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive are preferable. More preferably, it is an acrylic adhesive. More preferably, it is a cross-linkable acrylic pressure-sensitive adhesive. If necessary, a carboxylic acid compound, an isocyanate compound, a melamine compound, or a metal compound may be added to these pressure-sensitive adhesives as long as the properties are not impaired. Further, an ultraviolet absorber, a visible light absorber, a dye, an infrared absorber and the like may be added to the adhesive. Acrylic pressure-sensitive adhesives are excellent in light resistance, weather resistance, oil resistance, and the like, and are suitable for use as a shatterproof film.

  In the laminated film of the present invention, an easy-adhesion layer, an antireflection film, a hard coat layer, an ultraviolet absorbing layer, and a light transmittance control layer may be provided on at least one surface of the laminated film composed of at least five layers. These layers are not particularly limited, and various conventionally known techniques and the like can be used. By having these layers, in addition to being able to be adhered to glass such as a flat display as a glass protective film, it is possible to prevent reflection due to surface reflection and to prevent visibility deterioration due to scratches. preferable.

  In the present invention, it is preferable that the easy-adhesion layer is provided on one or both surfaces of the laminated film, and the adhesive layer is provided on the easy-adhesion layer. In such a case, since the adhesive strength between the laminated film and the pressure-sensitive adhesive is greatly improved, it is possible to further contribute to improving the adhesive strength with glass. The easy adhesion layer mentioned here includes polyester, modified polyester, acryl, modified acryl, polyurethane, modified polyurethane and the like. Further, when the particles are contained only in the very thin easy-adhesion layer, a very transparent laminated film having a high adhesive strength can be obtained while securing the winding property, which is more preferable. The thickness of the easy-adhesion layer is preferably 0.01 μm or more and 0.3 μm or less. More preferably, it is 0.02 μm or more and 0.2 μm or less.

  In the laminated film of the present invention, the haze is preferably 3% or less. It is more preferably at most 2%, further preferably at most 1%. If the haze is more than 3%, the visibility deteriorates, which is not preferable. In order to reduce the haze to 3% or less, it is preferable that the laminated film is composed of a laminated film of a rigid polyester and a rigid copolymerized polyester. Here, rigidity is defined as a material having a tensile modulus of elasticity of 1400 MPa or more. In such a case, there is no whitening over time, so that haze hardly increases. Further, as a method for reducing the haze to 3% or less, it is also preferable to reduce the particle concentration in the laminated film to 0.02% by weight or less. The particles referred to herein are particles for securing the winding characteristics of the film, and the average particle diameter is preferably 0.02 μm or more and 3.0 μm or less. More preferably, the particles are concentrated on the very surface layer of the film.

In the laminated film of the present invention, the surface impact strength is preferably 18 J / mm or more.
The surface impact strength needs to be 18 J / mm. It is more preferably 20 J / mm, particularly preferably from 25 J / mm to 100 J / mm. The surface impact strength refers to the impact absorption energy measured using a falling weight impact tester. Examples of the falling weight impact tester referred to here include a graphic impact tester manufactured by Toyo Seiki Co., Ltd. If it is less than the above range, the strength of the glass protective film is insufficient, and it is not possible to effectively prevent breakage of glass and scattering of broken glass pieces.

  In the laminated film of the present invention, it is preferable that at least one side has a pencil hardness of H or more. More preferably, it is 3H or more, and still more preferably 4H or more. When the pencil hardness is smaller than H, it is not preferable because the surface of the film is easily scratched and the visibility deteriorates when actually used as a glass protective film.

  The laminated film of the present invention preferably has an ultraviolet transmittance of 5% or less, more preferably 3% or less, and still more preferably 2% or less. If the ultraviolet transmittance is more than 5%, the laminated film is embrittled by the ultraviolet light, and the scattering prevention performance deteriorates with time, which is not preferable.

  In the present invention, the thickness of the laminated film is preferably 180 μm or more and 600 μm or less. The thickness is more preferably 200 μm or more and 550 μm or less, and further preferably 220 μm or more and 500 μm or less. When the film thickness is less than 180 μm, the penetration resistance as security performance is insufficient, which is not preferable. On the other hand, if the film thickness is 600 μm or more, it is not preferable because it is difficult to apply the film to glass.

  In the laminated film of the present invention, it is preferable that the laminated film is used by being attached to a building material window glass, a vehicle window glass, or a glass of a flat display element. Here, the flat display element is, for example, a CRT display, a liquid crystal display, a plasma display, an organic EL display, a field emission display, etc., and is particularly suitably used as a glass protective film of a flat CRT display or a plasma display.

  The laminated film of the present invention becomes a window with high security performance by being attached to a building material window glass or a vehicle window glass. The security performance is to lengthen the time required for intrusion such as breaking, prying, and burning, and the high glass protection performance of the present invention shows a high effect on these. In particular, when the laminated film of the present invention is gripped by a part of a glass fixing portion such as a sash, a dot point, and rubber together with glass, a higher effect is obtained, which is more preferable as a security window.

  Next, with respect to the laminated film of the present invention, a preferred method for producing a glass protective film will be described below as an example.

  A thermoplastic resin is prepared in the form of a pellet or the like. The pellets are pre-dried in hot air or under vacuum, if necessary, and supplied to an extruder. In the extruder, the resin that has been heated and melted to a temperature equal to or higher than the melting point is made uniform in the amount of resin extruded by a gear pump or the like, and foreign substances or denatured resin are filtered through a filter or the like. Further, the resin is discharged after being formed into a target shape by a die.

  As a method for obtaining a multilayer film, a method of laminating thermoplastic resins sent from different channels using two or more extruders into a multilayer using a multi-manifold die, a field block, a static mixer, or the like. Can be used. Further, these may be arbitrarily combined.

  The sheet having a laminated structure discharged from the die is extruded onto a cooling body such as a casting drum, and is cooled and solidified to obtain a casting film. At this time, it is preferable to use a wire-shaped, tape-shaped, needle-shaped or knife-shaped electrode to bring the electrode into close contact with a cooling body such as a casting drum by electrostatic force and to rapidly solidify.

  The casting film thus obtained may be biaxially stretched as needed. Biaxial stretching refers to stretching in the machine and transverse directions. The stretching may be performed sequentially biaxially or simultaneously in two directions. Further, re-stretching may be performed in the longitudinal and / or transverse directions.

  Here, the stretching in the longitudinal direction refers to stretching for giving the film a molecular orientation in the longitudinal direction, and is usually performed by a difference in peripheral speed of the roll. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. Although the stretching ratio varies depending on the type of the resin, it is usually preferably 2 to 15 times, and particularly preferably 2 to 7 times when polyethylene terephthalate is used.

  Further, on the surface of the film thus obtained, a coating may be applied using a coating technique such as a gravure coater or a metalling bar to provide an easy-adhesion layer, an easy-slip layer, and a high light transmittance layer. Absent.

  Further, the stretching in the transverse direction refers to stretching for giving the film orientation in the width direction. Usually, the film is conveyed while holding both ends of the film with clips using a tenter, and stretched in the width direction. The stretching magnification varies depending on the type of the resin, but usually 2 to 10 times is preferably used.

  The film thus biaxially stretched is preferably subjected to a heat treatment at a stretching temperature or higher and a melting point or lower in a tenter in order to impart flatness and dimensional stability, and after uniform slow cooling, is cooled to room temperature and wound up. .

After slitting the wound film to an arbitrary size, an adhesive layer or a hard coat layer is provided using a coater. As a coater, generally, a knife coater, a roll coater, a calendar coater, a comma coater, and the like are often used. Further, depending on the coating thickness and the viscosity of the material, the coating can be performed by a gravure coater or a rod coater. The pressure-sensitive adhesive composition can be applied by transfer from a release sheet in the same manner as in the case of transfer printing. The composition may be applied neat or with a suitable solvent or as an emulsion or latex. The appropriate monomers and additives can be applied directly to the substrate and cured in situ by heat, radiation, or other suitable methods known to those skilled in the art. Thus, a pressure-sensitive adhesive layer is formed from the adhesive composition. The thickness of the pressure-sensitive adhesive layer is preferably from 1 to 50 μm, more preferably from 1 to 15 μm.

  The glass protective film obtained in this way is a film that is compatible with both prevention of glass breakage and shattering and high transparency. In particular, it requires a high glass breakage prevention function and high transparency for flat panel CRT displays and plasma displays. It is suitable for a glass protective film for a flat display to be used.

The evaluation method of the physical properties used in the present invention will be described.
(Method of evaluating physical property values)
(1) Tear strength Tear strength was measured using a heavy load tear tester (manufactured by Toyo Seiki). The sample size was 60 mm in width, 70 mm in length, a notch of 20 mm from the end was made at the center in the width direction, and the indicated value when the remaining 50 mm was torn was read. The tear strength (N) was determined by converting the indicated value (gf). The tear strength was obtained by averaging the test results of five samples in each of the vertical direction and the horizontal direction. When the film was not torn because the film thickness was too large, measurement was impossible, but it was substantially 300 N / mm or more.

(2) Haze The haze was measured using a direct-reading haze meter (Suga Test Instruments Co., Ltd.). Haze (%) was calculated by dividing the diffuse transmittance by the total light transmittance and multiplying by 100.

(3) Adhesive strength Measured according to JIS A5759-1998 adhesive strength.

(4) Easy-adhesion layer Layer thickness The transmission electron microscope HU-12 type (manufactured by Hitachi, Ltd.) was used to determine the thickness of the laminated film provided with the easy-adhesion layer from a photograph obtained by observing the cross section. The thickness was an average value of 30 pieces in the measurement visual field.

(5) Ultraviolet transmittance The light transmittance was measured using a Hitachi spectrophotometer (U-3410 Spectrophotometer). The detection speed was 600 nm / min. And The ultraviolet transmittance was determined by averaging the transmittance every 10 nm in the wavelength range of 190 nm to 370 nm.

(6) Glass scattering prevention test Measured according to JIS A5759-1998 A method. However, the mass of the impact body was 68 kg, which is equivalent to 1.5 times the normal standard. As a result of the determination, the case where the amount of glass scattered is almost `` ◎ '' in the sense of excellent, the case where the amount of glass scattered is within the standard range is `` 良 '' in the sense of good, and the amount of scatter is out of the standard range The case was evaluated as “×” in the sense of failure. Among them, excellent and good ◎ and ○ were passed.

(7) Pencil hardness Pencils of various hardnesses were pressed against the film layer at an angle of 90 degrees according to JIS-K5400 and scratched with a load of 1 kg.

(8) Intrinsic Viscosity The value calculated from the following equation from the solution viscosity measured at 25 ° C. in orthochlorophenol was used. That is, ηsp / C = [η] + k [η] 2 · C, where ηsp = (solution viscosity / solvent viscosity) −1, C is the amount of dissolved polymer per 100 ml of solvent (g / 100 ml), and K is the Huggins constant ( 0.343). The solution viscosity and the solvent viscosity were measured with a pressing viscometer.

(9) Layer Configuration and Layer Thickness The layer configuration of the film was determined by observing the cross section of the film. That is, using a transmission electron microscope HU-12 type (manufactured by Hitachi, Ltd.), the cross section of the film was observed at a magnification of 3000 to 2000000 times, a cross-sectional photograph was taken, and the layer configuration and the thickness of each layer were measured.

(10) Security performance Compliant with European standard EN356. Detailed conditions are as follows. When the falling ball penetrated at a drop height of 1 m, the mark was x, when the drop height was 1 m, there was no penetration, and when the drop height was 1.5 m (P1A), there was no circle, and the drop height was 3.0 m. (P2A) when no penetration was observed, and when the drop height was 6 m (P3A) and there was no penetration, ◎ was observed.

Use steel ball: diameter 100mm, weight 4.1Kg
Falling method: Fall to each vertex of a regular triangle having a side of 130 mm near the center.

Test sample size: 900mm x 1100mm
Glass: float glass with a thickness of 5 mm (Example 1)
As the thermoplastic resin A, polyethylene terephthalate having an intrinsic viscosity of 0.65 was used. As the thermoplastic resin B, copolymerized polyethylene terephthalate (hereinafter abbreviated as CHDM copolymerized PET) obtained by copolymerizing 30% by mole of cyclohexanedimethanol was used. These thermoplastic resins A and B were each dried and then supplied to an extruder.
The thermoplastic resins A and B were each brought into a molten state at 280 ° C. by an extruder, passed through a gear pump and a filter, and then joined by a feed block. The combined thermoplastic resins A and B were supplied to a static mixer, and had a structure in which 16 layers of the thermoplastic resin A and 15 layers of the thermoplastic resin B were alternately laminated in the thickness direction. Here, the ejection amount was adjusted so that the lamination thickness ratio became A / B = 10. The thus obtained laminate comprising a total of 31 layers was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying static electricity.
The resulting cast film was heated with a group of rolls set at 90 ° C. and stretched 3.2 times in the machine direction. A corona discharge treatment is applied to both surfaces of the uniaxially stretched film in air, the wet tension of the base film is set to 55 mN / m, and a coating liquid for forming a laminated film comprising acrylic / silica particles having an average particle diameter of 140 nm is applied to the treated surface. Then, a slippery / adhesive layer was provided. Then, it was guided to a tenter, preheated with hot air at 100 ° C., and then stretched 3.3 times in the horizontal direction. The stretched film was directly heat-treated in a tenter with hot air at 150 ° C., gradually cooled to room temperature, and wound up. The thickness of the obtained film was 100 μm.
After slitting this film, an adhesive layer was formed by applying an adhesive compounded at the following ratio to one surface using a coater. Table 1 shows the obtained results.
Octyl acrylate 50 parts Vinyl acetate 50 parts Hydroxyethyl acrylate 5 parts Melamine resin 10.5 parts UV absorber 5 parts (Example 2)
Example 1 was the same as Example 1 except that the composition of the slippery / adhesive layer was polyurethane / silica particles having an average particle diameter of 140 nm. Table 1 shows the obtained results.

(Example 3)
The same procedure as in Example 1 was carried out except that the slippery / adhesive layer was made of polyester / melamine crosslinking agent / silica particles having an average particle diameter of 140 nm. Table 1 shows the obtained results.

(Example 4)
Two laminated films of Example 3 were laminated so that an adhesive layer was formed only on one side. The total thickness of the obtained film was 220 μm.

(Example 5)
Three laminated films of Example 3 were laminated so that an adhesive layer was formed only on one side. The total thickness of the obtained film was 330 μm.

(Example 6)
Four laminated films of Example 3 were laminated so that an adhesive layer was formed only on one side. The total thickness of the obtained film was 440 μm.

(Comparative Example 1)
Example 3 was the same as Example 3 except that the thermoplastic resin was a film consisting only of polyethylene terephthalate having an intrinsic viscosity of 0.65. Table 1 shows the obtained results.

(Comparative Example 2)
Claims 1 and 2 except that as the thermoplastic resin A, polyethylene terephthalate having an intrinsic viscosity of 0.65 to which 0.02 wt% of colloidal silica having an average particle size of 1.0 µm was added, and that an easy-slip and easy-adhesion layer was not provided. Same as above. Table 1 shows the obtained results.

  INDUSTRIAL APPLICABILITY The laminated film of the present invention can be used as a protective film for display glass such as window glass for building materials, window glass for vehicles, and flat displays.

Claims (12)

At least one side of a laminated film composed of at least five layers has an adhesive layer having an adhesive strength of at least 4 N / 10 mm width with glass and a tear strength of at least 50 N / mm. Laminated film. The laminated film according to claim 1, wherein a layer mainly composed of polyester and a layer mainly composed of copolyester are alternately laminated in a thickness direction by five or more layers. The laminated film according to claim 1, wherein the laminated film has an easy-adhesion layer on one or both surfaces thereof, and has an adhesive layer on the easy-adhesion layer. The haze is 3% or less, The laminated film in any one of Claims 1-3 characterized by the above-mentioned. The laminated film according to any one of claims 1 to 4, wherein a surface impact strength is 18 J / mm or more. The laminated film according to any one of claims 1 to 5, wherein an ultraviolet transmittance is 5% or less. The laminated film according to any one of claims 1 to 6, wherein the pencil hardness of at least one side is H or more. The laminated film according to any one of claims 1 to 7, wherein the film thickness is 180 µm or more and 600 µm or less. The laminated film according to any one of claims 1 to 8, which is used by being attached to a building material window glass or a vehicle window glass. A security window to which the laminated film according to claim 9 is attached. A security window characterized in that the laminated film is held together with the glass at the glass fixing portion. The laminated film according to any one of claims 1 to 8, wherein the laminated film is used by being attached to a front surface of a glass for a flat display element.