JP2015164798A - Decorative metallic luster film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative metallic luster film having excellent designing property of a metallic luster tone and tone stability without giving a color difference in a large area, and having excellent molding property.SOLUTION: The decorative metallic luster film comprises a biaxially oriented polyester film including a polyester layer A (denoted by A-layer hereinafter) and a polyester layer B (denoted by B-layer hereinafter) and having 50 or more layers each, alternately laminated in a thickness direction; and the film satisfies all of the following conditions (1) to (6). (1) A polyester resin composition constituting the B-layer contains a residue derived from diol of ethylene glycol and spiroglycol; (2) the polyester resin composition constituting the B-layer contains a residue derived from a dicarboxylic acid of terephthalic acid and cyclohexane dicarboxylic acid; (3) an absolute reflectance of the film is 60% or more in a wavelength range from 400 to 700 nm; (4) a color difference ΔE in a 1000 mm square is less than 2.0; (5) the film shows a stretching stress of 80 N or less at 150°C; and (6) the outermost surface layer is composed of A-layer, and the A-layer as the outermost surface layer has a thickness of 1 μm or more and 15 μm or less.

Description

  The present invention relates to a decorative metallic glossy tone film having excellent metallic gloss tone design, color tone stability that does not cause a color difference in a large area, and excellent moldability.

  In recent years, with the growing awareness of the environment, there has been an increasing demand for solvent-less coating, plating replacement, etc. in the decoration of molding materials such as building materials, automobile parts, mobile phones, home appliances and personal computers, and the introduction of decoration methods using films Progressing. As a decorative design, in order to improve the design, a wood-tone and cloth-tone, or a metal-decorated one is used. Above all, there is a high need for a metallic appearance because it can bring out a high-class feeling, but since molding becomes heavy with a metal, a resin substrate such as a film is decorated with a metallic luster. As a characteristic required for the decorative film, moldability that can follow the shape of the molded member is important.For example, when used for decorating a large-sized molded member such as a large household appliance such as a refrigerator or an automobile part, If the color tone is uneven, the appearance quality is impaired, so that the color tone is also required to be stable.

  Under such circumstances, in Patent Document 1, by providing a pinhole concealing layer on the decorative sheet, even if pinholes are generated in the metal thin film layer on which the metal material is deposited, the decorative sheet using the decorative sheet is used. A decorative sheet, a decorative molded product, and a manufacturing method thereof have been proposed in which the gloss and brightness of the molded product do not decrease.

  Moreover, in patent document 2, only the support body which consists of a film containing a heat ray absorber selectively accelerates | stimulates heat absorption, and it does not impair a moldability, but a decorative layer provided with metallic luster is a resin molded body. A transfer-type decorative sheet that can be transferred to the exterior, a method of manufacturing an exterior part using the same, an exterior part, and a home appliance using the same have been proposed.

Japanese Patent No. 3637298 JP 2013-71403 A

  The decorative sheet described in Patent Document 1 is provided with a pinhole concealing layer, so that the gloss and brightness of the decorative molded product do not decrease even if pinholes are generated in the metal thin film layer. However, pinholes in the metal thin film layer itself are not suppressed, and the appearance quality is not sufficient. Also, since the decorative sheet is a composite of resin and metal, it is difficult to recycle. When molding with an infrared heater, the metal material reflects and conceals infrared rays until the entire decorative sheet reaches the target temperature. It took a long time to produce a low productivity.

  The transfer type decorative sheet described in Patent Document 2 can transfer a decorative layer having metallic luster to a resin molded body without impairing moldability by containing a heat ray absorbent. However, since the decorative layer contains a metal material, it is difficult to recycle, there is a possibility that delamination of each layer forming the composite may occur, and the design that fully considers the moldability of the resin film There wasn't.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, have excellent design properties of metallic luster tone, color tone stability that does not feel a color difference in a large area, and scratch resistance, and is also called a flow mark An object of the present invention is to provide a decorative metallic glossy film having no appearance defect and excellent moldability.

The present invention employs the following means in order to solve such problems. That is, a biaxially stretched polyester film having a polyester layer A (hereinafter referred to as “A layer”) and a polyester layer B (hereinafter referred to as “B layer”), wherein 50 or more layers are alternately laminated in the thickness direction. A metallic glossy film for decoration, which satisfies all of 1) to (6).
(1) The polyester resin composition which comprises the said B layer contains the residue derived from the diol of ethylene glycol and spiroglycol.
(2) The polyester resin composition constituting the B layer contains a residue derived from dicarboxylic acid of terephthalic acid and cyclohexanedicarboxylic acid.
(3) The absolute reflectance in the wavelength band of 400 to 700 nm is 60% or more.
(4) The color difference ΔE within 1000 mm square is less than 2.0.
(5) The stretching stress at 150 ° C. is 80 N or less.
(6) The outermost layer is the A layer, and the thickness of the outermost layer A layer is 1 μm or more and 15 μm or less.

  By the present invention, it has excellent metallic luster design and color stability in a large area without color difference, anti-scratch resistance, no appearance defect called flow mark, and further excellent for moldability A metallic glossy film can be obtained. For example, it can be suitably used for decorating large-area molded members such as large home appliances and automobile parts.

FIG. 1 is a diagram showing the design layer thickness excluding the outermost layer of Examples 1 to 4 and Comparative Examples 1 to 5.

  The decorative metallic glossy film of the present invention has a polyester layer A (hereinafter referred to as “A layer”) and a polyester layer B (hereinafter referred to as “B layer”), and two or more layers are alternately laminated in the thickness direction. It is an axially stretched polyester film. The polyester resin composition constituting the polyester layer B contains residues derived from diols of ethylene glycol and spiroglycol. By adopting such a configuration, it is possible to obtain a decorative metallic glossy film excellent in texture as a metallic glossy tone and excellent in moldability.

  In the present invention, “alternately stacked in the thickness direction” means that the A layer and the B layer have a structure that appears alternately in the thickness direction. That is, it is preferable that the arrangement in the thickness direction of the A layer and the B layer in the film of the present invention is not in a random state. In addition, when the A layer, the B layer, and the C layer made of the resin C are included, CA ( A structure in which the C layer is laminated on the outermost layer or the intermediate layer, such as BA) n, CA (BA) nC, and A (BA) nCA (BA) m, may be employed. Here, n and m are integers. For example, when n = 3 in A (BA) n, it indicates that the layers are stacked in a permutation of ABABABA in the thickness direction.

  In the present invention, 50 layers or more of the A layer and the B layer must be included alternately. More preferably, it is 200 layers or more. Further, the total number of layers of the A layer and the B layer is preferably 600 layers or more. If the structure in which 50 layers or more of the A layer and the B layer are laminated is not included, sufficient reflectivity cannot be obtained, and the appearance of high glossy metallic luster is not obtained. Further, when 200 layers or more are alternately included in the A layer and the B layer, the reflectance in the wavelength band of 400 to 700 nm can be set to 30% or more. Further, when the total number of layers of the A layer and the B layer is 600 or more, it becomes easy to set the reflectance in the wavelength band of 400 to 700 nm to 60% or more, and it has a very bright metallic luster appearance. It becomes easy. Further, the upper limit value of the number of layers is not particularly limited, but it is 3000 layers or less in consideration of a decrease in wavelength selectivity accompanying a decrease in stacking accuracy due to an increase in the size of the device or an increase in the number of layers. This is common in normal use.

  The polyester resin composition (hereinafter referred to as polyester resin A) constituting the A layer in the present invention has a structure obtained by polycondensation of a dicarboxylic acid component and a diol component. The polyester resin A may be a copolymer. Typical examples of the polyester resin A include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene diphenylate, and the like. In particular, polyethylene terephthalate is preferable because it is inexpensive and can be used in a wide variety of applications.

  In the present invention, the copolyester has a structure obtained by polycondensation using at least three or more dicarboxylic acid components and diol components. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 4,4 -Diphenylsulfone dicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexane dicarboxylic acid and ester-forming derivatives thereof. Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 2,2-bis (4, -Β-hydroxyethoxyphenyl) propane, isosorbate, 1,4-cyclohexanedimethanol, spiroglycol, and ester-forming derivatives thereof. In the decorative metallic glossy film of the present invention, the polyester resin A is preferably polyethylene terephthalate or polyethylene naphthalate.

  It is necessary that the polyester resin composition (hereinafter referred to as polyester resin B) constituting the B layer in the present invention contains residues derived from diols of ethylene glycol and spiroglycol. Examples thereof include copolymer polyesters having a structure obtained by copolymerization using ethylene glycol and spiro glycol, and polyesters obtained by blending polyesters having a structure obtained by polymerization using the diol. This structure is excellent in moldability and hardly causes delamination.

  Moreover, it is necessary for the polyester resin B in this invention to contain the residue derived from the dicarboxylic acid of a terephthalic acid and cyclohexane dicarboxylic acid. Examples of such a polyester include a copolymer polyester obtained by copolymerizing terephthalic acid and cyclohexanedicarboxylic acid, or a polyester obtained by blending a polyester containing a terephthalic acid residue and a polyester containing a cyclohexanedicarboxylic acid residue. The polyester containing a cyclohexanedicarboxylic acid residue has a large difference between the in-plane average refractive index of the A layer and the in-plane average refractive index of the B layer, and a high reflectance is obtained. Moreover, since the glass transition temperature difference with polyethylene terephthalate or polyethylene naphthalate is small, it is not over-stretched at the time of molding, and delamination hardly occurs.

  Further, the polyester resin A and the polyester resin B in the present invention may contain other resins as long as the object of the present invention is not impaired. Examples thereof include resins such as polyolefin resins, polystyrene resins, polyacrylic resins, polycarbonate resins, polysulfone resins, and cellulose resins. Moreover, there is no problem even if particles such as colloidal silica, calcium carbonate, titanium oxide, and crosslinked polystyrene are contained in order to impart functions such as winding characteristics, rigidity, and optical characteristics. The addition amount of these resins and particles is not limited as long as the effects of the present invention are not impaired, but a preferable range is less than 25% by mass.

  The in-plane average refractive indexes of the A layer and the B layer constituting the decorative metallic glossy film of the present invention are not equal in order to develop a metallic glossy tone. The in-plane average refractive index of the A layer is preferably relatively higher than the in-plane average refractive index of the B layer. The difference between the in-plane average refractive index of the A layer and the in-plane average refractive index of the B layer is preferably 0.03 or more. More preferably, it is 0.05 or more, More preferably, it is 0.1 or more. When the in-plane average refractive index difference is smaller than 0.03, sufficient reflectance cannot be obtained. Further, when the difference between the in-plane average refractive index and the thickness direction refractive index of the A layer is 0.03 or more, and the difference between the in-plane average refractive index and the thickness direction refractive index of the B layer is 0.03 or less, the incident angle Even if becomes larger, the reflectance of the reflection peak does not decrease, which is more preferable. In order to increase the difference in refractive index between the A layer and the B layer, the crystal melting temperature of the resin of the B layer is preferably 235 ° C. or less, and by doing so, the B layer is relaxed in orientation by heat treatment of the tenter. The refractive index difference becomes larger. In addition, it is preferable that the B layer is amorphous because crystallization hardly occurs even at high temperatures, so that a problem such as whitening does not occur. The term “amorphous” as used herein means that the heat of crystal melting when the temperature is raised at a rate of temperature rise of 5 ° C./min in differential calorimetry (DSC) is less than 0.1 mJ / mg. For example, polybutylene terephthalate (hereinafter referred to as “polybutylene terephthalate”) can be used as a resin that increases the content of copolymer polyester having a structure obtained by copolymerization using ethylene glycol and spiro glycol, and can relax orientation of layer B by heat treatment. , Sometimes referred to as PBT), a desired low refractive index and a high reflectivity of the film accompanying it can be obtained.

  As a preferable combination of the polyester resin A and the polyester resin B, a combination in which the glass transition temperature difference between the polyester resin A and the polyester resin B is 20 ° C. or less is preferable. When the glass transition temperature difference is larger than 20 ° C., the thickness uniformity at the time of forming the laminated film becomes poor, and the appearance of metallic luster tends to be poor. Also, when a laminated film is formed, problems such as overstretching tend to occur.

  The metallic glossy tone film for decoration of the present invention needs to have an absolute reflectance of 60% or more in a wavelength band of 400 nm to 700 nm. Thereby, the film which has the design property excellent in the metallic luster tone can be obtained. For this purpose, the band to be reflected can be brought close to a desired value by gradually increasing or decreasing the layer thickness within a range of 20 nm to 500 nm. A more ideal range of the layer thickness is 30 nm or more and 370 nm or less.

Moreover, it is more preferable that the absolute reflectance in the wavelength band of 400 nm to 1000 nm on both surfaces of the film is 20% or more. In this case, the glossy feeling is maintained after molding, and the color hardly changes depending on the viewing angle. This is because the absolute reflectance is also 20% or higher on the higher wavelength side (700 nm or more) than visible light. Even when the film thickness is reduced by stretching or the reflection band is shifted to the lower wavelength side depending on the viewing angle. This is because the absolute reflectance in the visible light region can be maintained at 20% or more. More preferably, the absolute reflectance in the wavelength band of 400 nm to 1000 nm is 60% or more. The higher the absolute reflectance, the higher the glossiness and the metallic gloss appearance. The reflection band is designed so that reflection occurs based on the thickness of each layer based on the following formula A. The reflectance is controlled by the difference in refractive index between the A layer and the B layer and the number of layers of the A layer and the B layer.
2 × (na · da + nb · db) = λ Formula A
na: In-plane average refractive index of the A layer nb: In-plane average refractive index of the B layer da: Layer thickness (nm) of the A layer
db: Layer thickness of layer B (nm)
λ: main reflection wavelength (primary reflection wavelength)
When the absolute reflectance in the wavelength band of 400 nm to 700 nm is less than 60%, the metallic luster-like appearance with high luminance is not achieved, and the designability to home appliances and automobile parts may be inferior.

  Most preferably, the decorative metallic glossy film of the present invention has an absolute reflectance of 20% or more in the wavelength band of 400 to 1400 nm. In this case, even after deep drawing at the time of high temperature molding, the color change hardly occurs. More preferably, it is 50% or more. In this case, no color change occurs even after deep drawing at high temperature. More preferably, it is 75% or more, there is no change in color, and the metal gloss tone is excellent.

The metallic glossy tone film for decoration of the present invention needs to have a color difference ΔE within 1000 mm square of less than 2.0. In such a case, the appearance quality is such that a person does not feel a color difference. More preferably, it is less than 1.0, and most preferably less than 0.5. When the color difference ΔE is less than 0.5, color unevenness hardly occurs. When the color difference is 2.0 or more, the color difference becomes as perceived by humans, and the appearance of the decorative member obtained by molding the film may not be uniform. As a specific means for achieving a color difference ΔE within 1000 mm square of less than 2.0, for example, in the production of a biaxially stretched polyester film having A layers and B layers and alternately laminated in the thickness direction by 50 layers or more, Polyester resin A and polyester resin B are co-extruded with a temperature deviation of 3% or less and a shear rate of 10 s ^-1 or less, laminated alternately in the thickness direction using a feed block having a slit-like flow path, and flow into a flat die. In this case, it can be achieved by producing a molten resin having a viscosity deviation of 6% or less from the slit flow path inlet to the outlet of the feed block.

The decorative metallic glossy film of the present invention needs to have a stretching stress at 150 ° C. of 80 N or less. In such a case, the moldability is excellent, and in any molding such as vacuum molding, vacuum pressure molding, plug assist vacuum pressure molding, in-mold molding, insert molding, cold molding, press molding, draw molding, etc. It becomes easy to mold into a shape. More preferably, the stretching stress at 150 ° C. is 70 N or less. In such a case, molding is possible even with a higher drawing ratio. In order for the stretching stress at 150 ° C. to be 80 N or less, the polyester resin A is a crystalline resin, and the polyester resin B is an amorphous resin having a bulky group such as spiroglycol, cyclohexanedimethanol, neopentylglycol or the like. Preferably there is. In such a case, since the polyester resin B is hardly oriented and crystallized even after biaxial stretching, the stretching stress can be lowered.
In the laminated film of the present invention, the outermost layer is the A layer, and the thickness of the outermost layer A layer is required to be 1 μm or more and 15 μm or less. More preferably, they are 5 micrometers or more and 10 micrometers or less. When the thickness is less than 1 μm, a flow mark due to the instability phenomenon of the laminated interface is likely to occur, resulting in poor appearance and partial coloring. When exceeding 15 micrometers, the whole thickness of a laminated | multilayer film will become thick, and it may become difficult to handle because it is too strong as a shaping | molding member for decorating.

  When the decorative metallic glossy tone film of the present invention is used in a molded product, the molded product is optionally combined with the decorative metallic glossy tone film of the present invention laminated on the surface of the base material. It is preferable to have a colored layer or a printed layer. The material of the base material is not particularly limited as long as it can be molded by various molding methods. For example, acrylic resin, polycarbonate resin, polybutylene terephthalate resin, acrylonitrile / styrene copolymer (AS resin), FPR resin, polystyrene resin. Resin such as polyether methylene resin and polypropylene foam resin, metal member, glass member and the like.

  As a method of integral molding of resin molding and film, there is a method of using a decorative molding sheet or film on which a pattern or the like is printed and integrating the sheet on the surface of the base material of the molded body by in-mold decorative molding. Although widely used, the method is not particularly limited, and other methods such as injection molding, press molding, in-mold transfer molding, thermoject method, CFI method, and the like may be used. Moreover, when the said base material is plate shape, you may laminate.

  A hard coat layer, a colored layer, an easy-slip layer, an antistatic layer, an anti-abrasion layer, an antireflection layer, an ultraviolet absorption layer, a printing layer, a transparent conductive layer, a gas barrier on the surface of the metallic glossy film for decoration of the present invention Functional layers such as a layer, a hologram layer, a release layer, an adhesive layer, an adhesive layer, and an emboss layer may be formed.

  Since the film of the present invention is composed of a polymer and basically does not contain metal or heavy metal, it has a low environmental load, is excellent in recyclability, and does not cause electromagnetic interference. In addition, since various molding methods such as vacuum molding, vacuum pressure molding, plug assist vacuum pressure molding, in-mold molding, insert molding, cold molding, and press molding can be applied, three-dimensional shapes shall be formed at low cost. Is possible. The molding method is not particularly limited, and generally known molding methods such as a vacuum molding method, a vacuum / pressure molding method, a blow (blowing) molding method, a press molding method, an insert injection molding method, an in-mold (mold) Inner) It can be molded by a molding method, an extrusion molding method or the like.

  The decorative part obtained by laminating the metallic glossy film for decoration of the present invention on glass has an excellent design property of metallic glossy tone and color stability that does not feel a color difference in a large area. It can be suitably used as a home appliance made of For example, in the configuration of resin sheet / decorative metallic glossy film for decoration / printing layer / transparent adhesive layer, the transparent adhesive layer side and the glass plate are laminated and used for decorating exterior members of large refrigerators. be able to.

  As a specific example of a preferable method for producing a decorative metallic glossy film of the present invention, a method for producing a biaxially stretched polyester film by a multilayer lamination extrusion method will be described below.

  Two types of polyester resin A and polyester resin B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to a separate extruder. The resin supplied to the extruder is heated and melted at the melting point or higher in the extruder. In the present invention, the temperature deviation of each resin in the molten state is preferably 3 ° C or lower, more preferably 2 ° C or lower, and 1 ° C or lower. Is most preferred. When the temperature deviation of each resin exceeds 3%, it is not preferable because a color difference as perceived by humans is obtained. In addition, when the feed blocks having slit-like flow paths are alternately stacked in the thickness direction and allowed to flow into the flat die, the viscosity deviation of each resin in the molten state from the slit-like flow path inlet to the outlet of the feed block is 6 % Or less, preferably 3% or less, and most preferably 1.5% or less. When deviation occurs in the viscosity of each resin, the amount of resin flowing through the slit-like flow path of the feed block changes, and the layer thickness of each resin changes. When the viscosity deviation of each resin exceeds 6%, it is not preferable because a color difference as perceived by humans is obtained.

The heat-melted polyester resins A and B are coextruded with an extruder screw, and the shear rate is 10 s ⁻¹ or less, and most preferably 5 s ⁻¹ or less. This is because a change in the viscosity of the resin may occur depending on the shear rate, and color tone fluctuation due to this phenomenon is avoided.

When the shear rate exceeds 10 s ⁻¹ , the change in the resin viscosity with respect to a minute change in the shear rate is large, which is not preferable from the viewpoint of robustness.

  The resin melted by heating to a temperature higher than the melting point is made uniform in the amount of resin extruded by a gear pump or the like, and foreign matter or modified resin is removed through a filter or the like.

  Polyester resin A and polyester resin B sent out from different flow paths using these two or more extruders are then fed into the multilayer laminating apparatus. As the multilayer stacking apparatus, a multi-manifold die or a field block can be used. Moreover, you may combine these arbitrarily. The structure of the feed block has at least one member in a comb-shaped slit plate having a large number of fine slits, and resin A and resin B extruded from two extruders pass through each manifold. Introduced into the slit plate. Here, since the resin A and the resin B selectively flow alternately into the slit through the introduction plate, finally, a multilayer film such as A / B / A / B / A... Can be formed. . In addition, the number of layers can be increased by further overlapping the slit plates. Further, when the resin C is provided on both surface layers, the resin C is introduced from the third extruder to the surface layer side of the three-layer composite device (feed block), and the multilayer film is introduced to the center layer, thereby providing C A multilayer film such as / A / B / A... A / B / A / C can be formed.

  The melt thus multilayered is discharged in the form of a sheet from the T die onto the cooling drum. In that case, for example, a method of applying static electricity using a wire-like electrode or a tape-like electrode, a casting method in which a water film is provided between a casting drum and an extruded polymer sheet, and a casting drum temperature from a glass transition point of a polyester resin to ( A sheet-like polymer is brought into close contact with the casting drum by a method of sticking the extruded polymer at a glass transition point of -20 ° C or a combination of these methods, and solidified by cooling to obtain an unstretched film. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness.

  Subsequently, the unstretched film is stretched in the longitudinal direction and then stretched in the width direction, or after being stretched in the width direction and then stretched in the longitudinal direction, or in the longitudinal direction and the width direction of the film. The film is stretched by a simultaneous biaxial stretching method or the like that stretches almost simultaneously.

  As a draw ratio in such a drawing method, preferably 2.5 to 3.5 times, more preferably 2.8 to 3.5 times, and particularly preferably 3 to 3.4 times are employed in each direction. The The stretching speed is desirably 1,000 to 200,000% / min. The stretching temperature may be a glass transition point to (glass transition point + 50 ° C.), more preferably 90 to 130 ° C., particularly preferably a longitudinal stretching temperature of 100 to 120 ° C. and a stretching in the width direction. The temperature is preferably 90 to 110 ° C. Further, the stretching may be performed a plurality of times in each direction.

  Furthermore, the film is heat-treated after biaxial stretching. The heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. This heat treatment is performed at a temperature of 120 ° C. or higher and below the melting point of the polyester, but is preferably a heat treatment temperature of 200 to 240 ° C. From the viewpoint of transparency and dimensional stability of the film, it is more preferably 210 to 235 ° C. The heat treatment time can be arbitrarily set within a range not deteriorating the characteristics, and is preferably 1 to 60 seconds, more preferably 1 to 30 seconds. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction. Further, before the transverse stretching step, at least one surface can be subjected to corona treatment or a coating layer can be provided in order to improve the adhesive force with the ink printing layer, the adhesive, and the vapor deposition layer. The coating liquid at this time is applied to the transparent substrate using a known coating means such as a roll coater, a gravure coater, a micro gravure coater, a bar coater, a die coater, or a dip coater.

  Next, the case of simultaneous biaxial stretching will be described. In the case of simultaneous biaxial stretching, the resulting cast film is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then, such as slipperiness, easy adhesion, antistatic properties, etc. The function may be imparted by in-line coating.

  Next, the cast film is guided to a simultaneous biaxial tenter, and conveyed while holding both ends of the film with clips, and stretched in the longitudinal direction and the width direction simultaneously and / or stepwise. As simultaneous biaxial stretching machines, there are pantograph method, screw method, drive motor method, linear motor method, but it is possible to change the stretching ratio arbitrarily and drive motor method that can perform relaxation treatment at any place or A linear motor system is preferred. Although the stretching magnification varies depending on the type of resin, it is usually preferably 6 to 50 times as the area magnification. When polyethylene terephthalate is used as one of the resins constituting the laminated film, the area magnification is 8 to 30 times. Is particularly preferably used. In particular, in the case of simultaneous biaxial stretching, it is preferable to make the stretching ratios in the longitudinal direction and the width direction the same and to make the stretching speeds substantially equal in order to suppress the in-plane orientation difference. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises a laminated | multilayer film are preferable.

  In order to impart flatness and dimensional stability, the biaxially stretched film is preferably subsequently subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter. In order to suppress the distribution of the main alignment axis in the width direction during this heat treatment, it is preferable to perform a relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone. After being heat-treated in this way, it is gradually cooled gradually, cooled to room temperature, and wound up by a winder. Moreover, you may perform a relaxation | loosening process in a longitudinal direction and / or the width direction at the time of annealing from heat processing as needed. In this case, the relaxation treatment is instantaneously performed in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone.

  EXAMPLES Hereinafter, although this invention is demonstrated along an Example, this invention is not restrict | limited by these Examples. Various characteristics were measured by the following methods.

(1) Intrinsic viscosity The intrinsic viscosity of the polyester resin and the film was measured at 25 ° C. using an Ostwald viscometer after dissolving the polyester in orthochlorophenol.

(2) Composition of polyester Resin or film is dissolved in hexafluoroisopropanol (hereinafter referred to as HFIP) or a mixed solvent of HFIP and chloroform, and each monomer residue and by-product using ¹ H-NMR and ¹³ C-NMR. The content of diethylene glycol was quantified.

(3) Film thickness Using a digital micrometer μ-Mate M-30 manufactured by Sony Precision Technology Co., Ltd., any 10 film thicknesses were measured, and the average value was taken as the film thickness.

(4) Stretching stress at 150 ° C. The film was cut into a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction, respectively, to prepare samples. Using a tensile tester (Orientec Tensilon UCT-100), an initial tensile chuck distance was set to 50 mm, and a tensile speed was set to 300 mm / min. For the measurement, a film sample was set in a constant temperature bath set in advance to a temperature of 150 ° C., and a tensile test was performed after preheating for 60 seconds. The maximum stretching stress in each direction is measured from the obtained load-strain curve, and each direction is performed with n number = 5, and the average value of three points excluding the maximum value and the minimum value is calculated, and the longitudinal direction and the width direction are calculated. The average value was taken as the measurement result.

(5) Absolute reflectance It measured using the spectrophotometer UV-3150 by Shimadzu Corporation.
An absolute reflectance measuring apparatus ASR-3105 having an incident angle of 5 ° was attached, and the absolute reflectance in the wavelength band of 400 to 700 nm was measured under the following conditions according to the attached instruction manual.

  Ten laminated film rolls with a winding length of 1000 m and a width of 1100 mm are manufactured, one 1000 mm square film sample is cut out from the surface layer of each film roll, and the absolute reflectance is measured at 100 mm pitches in the width direction and the longitudinal direction. The average value was used as the absolute reflectance of each sample, and the average value of the absolute reflectance of 10 samples was used as the measurement result.

Scanning speed: High speed Sampling pitch: 1 nm
Measurement mode: Single Slit width: 30nm
Light source switching wavelength: 360 nm
Detector switching wavelength: 805 nm
S / R switching: Standard Detector lock: Automatic Slit program: Standard (6) Color difference ΔE within 1000 mm square
Measurement was performed using a spectrocolorimeter CM-3600d manufactured by Konica Minolta Sensing Co., Ltd. As a measurement procedure, zero calibration of reflectance was performed with the zero calibration box attached to the spectrocolorimeter, and then 100% calibration was performed using the attached white calibration plate ^. The chromaticity (a ^* , b ^* ) was measured, and the maximum value of the color difference ΔE of the film was determined.

Specifically, ten laminated film rolls having a winding length of 1000 m and a width of 1100 mm were produced, and one 1000 mm square film sample was cut out from the surface layer of each film roll, and the brightness was measured at 100 mm pitches in the width direction and the longitudinal direction. L * and chromaticity (a ^* , b ^* ) are measured, and the average value is set as the lightness L * and chromaticity (a ^* , b ^* ) of each sample, and 10 lightness L * and chromaticity (a ^* , B ^* ) based on the average value of each sample, the color difference ΔE from the measurement location of each sample is calculated by the following formula, and the average value of the color difference ΔE is calculated for each sample. The color difference ΔE within 1000 mm square was determined. Here, the closer the color difference ΔE is to 0, the more stable the color tone. On the other hand, when the color difference ΔE is 2.0 or more, the user feels the color by visual observation.

Color difference ΔE = ((ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ) ^1/2
SCI values were used for the brightness and chromaticity used in the calculation of saturation.

Mode: Reflection, SCI / SCE simultaneous measurement Measurement diameter: 8mm
Light source: D65
Viewing angle: 10 degrees Sample: Black vinyl tape is pasted on the non-measurement side (N021 Tokuhaba manufactured by Nitto Denko)
(7) Formability From the measurement results of (4) 150 ° C. stretching stress, the formability was evaluated according to the following criteria.
(Circle): 80N or less x: More than 80N (8) Metal glossiness The metal glossiness was evaluated on the following reference | standard from the measurement result of said (5) absolute reflectance.
○: 60% or more x: less than 60% (9) Color tone stability Above (6) Color difference ΔE within 1000 mm square, the number of rejected sheets with a color difference ΔE of 2 or more in 10 samples is counted, and color tone stability Was evaluated according to the following criteria.
O: Number of rejects 0 x: Number of rejects 1 or more (10) Layer thickness, number of layers, layered structure The layer structure of the laminated film, which is a half mirror material, is transmitted through a sample cut out of a cross-section using a microtome. It was determined by observation with a scanning electron microscope (TEM). That is, using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), the cross section of the film was magnified 10000 to 40000 times under the condition of an acceleration voltage of 75 kV, a cross-sectional photograph was taken, the layer configuration, and the thickness of each layer Was measured. In some cases, in order to obtain high contrast, a dyeing technique using a known RuO4 or OsO4 is used.

Approximately 40,000 times TEM photograph image obtained from the above device is saved to a personal computer as a compressed image file (JPEG) by processing at a print magnification of 620,000 times, and then image processing software Image-Pro This file was opened and image analysis was performed using Plus ver.4 (distributor Planetron Co., Ltd.). In the image analysis processing, the relationship between the thickness in the thickness direction and the average brightness of the region sandwiched between the two lines in the width direction was read as numerical data in the vertical thick profile mode. Using spreadsheet software (Excel 2000), the data of position (nm) and brightness was adopted in sampling step 6 (decimation 6), and then numerical processing of a three-point moving average was performed. Furthermore, the data obtained by periodically changing the brightness is differentiated, and the maximum value and the minimum value of the differential curve are read by a VBA (Visual Basic For Applications) program. It was calculated as the layer thickness of one layer. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated.
(11) Method for evaluating interface instability phenomenon such as flow mark Whether or not the interface instability phenomenon has occurred is determined by visually inspecting 10 formed 1.5 m square multilayer film samples under a fluorescent lamp. It was. The thickness of the multilayer film and the layer itself are clearly disturbed, and wavy irregularities can be visually confirmed. In the case where the number of multilayer films judged to be defective was zero, it was marked as ◯, and otherwise it was marked as x.
(12) Evaluation of imprints Using a hardness meter “HARDNESS TESTER No13881” manufactured by Shimadzu Corporation, the film surface was weighted with a hardness meter under the following conditions to forcibly form “imprints” and the maximum deformation depth of the sample The maximum depth is measured using a surface shape measuring device VertScan 2.0, and the deformation amount (nm) is calculated. The deformation amount was less than 1000 nm, and 1000 nm or more was evaluated as x.
Load: 0.9kgf (11.1MPa)
Weighted time: 5 minutes Hardness meter Tip: φ1mm
Sample size: 100mm x 100mm
Surface shape measuring device: VertScan 2.0 manufactured by Ryoka System Co., Ltd.
Measurement environment: Temperature 23 ° C, humidity 65% RH

Example 1
Two types of polyester resins A and B were used. Polyester terephthalate (hereinafter sometimes referred to as PET) [Toray F20S] having an intrinsic viscosity of 0.65, a crystal melting temperature of 255 ° C., a crystal melting heat of 41 mJ / mg, and a crystallization temperature of 155 ° C. is used as the polyester resin A. As resin B, PET [Toray F20S] 10% by mass, polyethylene terephthalate (hereinafter referred to as SPG copolymer) obtained by copolymerization of 29 mol% of cyclohexanedicarboxylic acid with respect to all phthalic acid components and 21 mol% of spiroglycol with respect to all diol components 70% by mass (sometimes referred to as PET), 10% by mass of polybutylene terephthalate (hereinafter, also referred to as PBT) [Toraycon 1100S manufactured by Toray], 10% by mass of polybutylene terephthalate [Toraycon 1200S manufactured by Toray], and the polyester resin composition All things Respect, extruded and melt-kneaded antioxidant [ADEKA made "Stab" (registered trademark) AS36] 0.05% by mass in a vented twin-screw extruder was used to discharge was solidified with cold water chip.

  The polyester resin A and the polyester resin B in which the crystalline resin was dispersed were respectively supplied to separate twin-screw extruders a and b with a vent.

Polyester resin A, shear rate 2.5 s ^-1 in an extruder a, polyester resin B crystalline resin is dispersed, and a molten state at a shear rate of 3.8S ^-1 in an extruder b. Here, the respective resin temperatures measured immediately before the entrance of the slit-like flow path of the feed block are polyester resin A, maximum temperature 280.2 ° C., minimum temperature 280.0 ° C., polyester resin B, maximum temperature 290.2. It controlled so that it might become a temperature range of ° C and the minimum temperature 290.0 ° C. Two types of polyester resins in the molten state were merged in a 901-layer feed block having three members each having 301 slits through individual gear pumps and filters. The surface layer portions on both sides are made of polyester resin A, polyester resin A and polyester resin B are alternately laminated, and the layer thickness of the layer made of polyester resin A and the layer made of polyester resin B is set to a discharge ratio by a gear pump. Polyester resin A / polyester resin B was adjusted while being measured so that 1.1 / 1.0. Subsequently, a rotating cooling body (casting) which is led to a flat die and continuously discharged as a sheet-like melt and is adjusted to a surface temperature of 25 ° C. while depositing an electrostatic charge from the upper surface to the extruded sheet-like melt. A cast film was obtained by bringing into close contact with a drum) and rapidly cooling and solidifying.

  The obtained cast film is heated by a roll group set at 75 ° C., and then rapidly heated by a radiation heater from both sides of the film between the stretching sections of 100 mm, and 3.3 times in the film transport direction, that is, the longitudinal direction. The film was stretched and then cooled once to obtain a uniaxially stretched film. Next, a laminate-forming film coating liquid composed of (polyester resin having a glass transition temperature of 18 ° C.) / (Polyester resin having a glass transition temperature of 82 ° C.) / Silica particles having an average particle diameter of 100 nm is applied to both sides of the uniaxially stretched film, and transparent・ Easily slippery / adhesive layer was formed.

  The obtained uniaxially stretched film was led to a tenter, preheated with hot air at 100 ° C., and stretched 3.5 times at 110 ° C. in the width direction of the film perpendicular to the conveying direction, that is, in the transverse direction. The stretched film is directly heat-treated in a tenter with hot air at 230 ° C., then subjected to a relaxation treatment of 5% in the width direction at the same temperature, cooled to room temperature, wound up with a winder, a film thickness of 100 μm, width Ten biaxially stretched polyester film rolls having a length of 1100 mm and a winding length of 1000 m were produced to obtain a metallic glossy film for decoration. The design layer thickness excluding the outermost layer of the decorative metallic glossy film is as shown in FIG. 1, and the outermost layer lamination thickness is 3 μm.

(Example 2)
The resin temperature of the polyester resin B measured immediately before the entrance of the slit-like flow path of the feed block is controlled to be within the temperature range of the highest temperature 291.0 ° C. and the lowest temperature 290.0 ° C., and the outermost layer lamination thickness is 5 μm. Except that, ten biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced in the same manner as in Example 1 to obtain a metallic glossy film for decoration.

(Example 3)
The resin temperature of the polyester resin B measured immediately before the slit-like flow path entrance of the feed block is controlled to be within the temperature range of the maximum temperature 291.5 ° C. and the minimum temperature 290.0 ° C., and the outermost layer lamination thickness is 5 μm. Except that, ten biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced in the same manner as in Example 1 to obtain a metallic glossy film for decoration.

Example 4
The resin temperature of the polyester resin B measured immediately before the entrance of the slit-like flow path of the feed block is controlled so as to be within the temperature range of the maximum temperature 293.0 ° C. and the minimum temperature 290.0 ° C., and the outermost layer lamination thickness is 10 μm Except that, ten biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced in the same manner as in Example 1 to obtain a metallic glossy film for decoration.

(Comparative Example 1)
The same as in Example 1 except that the resin temperature of the polyester resin B measured immediately before the entrance of the slit-like flow path of the feed block was controlled so as to be in the temperature range of the maximum temperature 296.0 ° C. and the minimum temperature 290.0 ° C. Thus, ten biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced.

(Comparative Example 2)
The same as in Example 1 except that the resin temperature of the polyester resin B measured immediately before the slit-like flow path entrance of the feed block was controlled to be within the temperature range of the maximum temperature 298.0 ° C and the minimum temperature 290.0 ° C. Thus, ten biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced.

(Comparative Example 3)
As polyester resin B, a copolymerized polyester obtained by copolymerizing 30 mol% of 1,4-cyclohexanedimethanol with respect to the glycol component (hereinafter sometimes referred to as PETG) [GN001 made by Eastman Chemical] 82 mass%, PET [Toray F20S] 18% by mass was mixed, and in the same manner as in Example 1 except that it was melted at a shear rate of 4.2 s ^-1 in an extruder b, a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m. Ten axially stretched polyester film rolls were produced.

(Comparative Example 4)
As polyester resin B, a copolymerized polyester obtained by copolymerizing 30 mol% of 1,4-cyclohexanedimethanol with respect to the glycol component (hereinafter sometimes referred to as PETG) [GN001 manufactured by Eastman Chemical] 41 mass%, PET [Toray F20S] In the same manner as in Example 1 except that 59% by mass was mixed and melted in the extruder b at a shear rate of 4.2 s ⁻¹ , the film thickness was 100 μm, the width was 1100 mm, and the winding length was 1000 m. Ten axially stretched polyester film rolls were produced.

(Comparative Example 5)
As the polyester resin B, PET [Toray F20S] was used, and the film thickness was 100 μm, the width was 1100 mm, and the winding length was the same as in Example 1 except that the molten state was obtained with an extruder b at a shear rate of 3.5 s ⁻¹ . Ten biaxially stretched polyester film rolls having a thickness of 1000 m were produced.
(Comparative Example 6)
10 biaxially stretched polyester film rolls having a film thickness of 100 μm, a width of 1100 mm, and a winding length of 1000 m were produced in the same manner as in Example 1 except that the outermost layer lamination thickness was set to 0.8 μm. A toned film was obtained.
(Comparative Example 7)
The resin temperature of the polyester resin B measured immediately before the slit-like flow path inlet of the feed block is controlled to be within the temperature range of the maximum temperature 291.0 ° C. and the minimum temperature 290.0 ° C. Except having set it as 8 micrometers, it carried out similarly to Example 1, and manufactured ten biaxially-stretched polyester film rolls with a film thickness of 100 micrometers, width of 1100 mm, and winding length of 1000 m, and obtained the metallic glossy tone film for decorating.

(Example 8)
The resin temperature of the polyester resin B measured immediately before the slit-like flow path entrance of the feed block is controlled so as to be within a temperature range of a maximum temperature of 291.5 ° C. and a minimum temperature of 290.0 ° C. Except having set it as 8 micrometers, it carried out similarly to Example 1, and manufactured ten biaxially-stretched polyester film rolls with a film thickness of 100 micrometers, width of 1100 mm, and winding length of 1000 m, and obtained the metallic glossy tone film for decorating.

Example 4
The resin temperature of the polyester resin B measured immediately before the slit-like flow path inlet of the feed block is controlled so as to be within a temperature range of a maximum temperature of 293.0 ° C. and a minimum temperature of 290.0 ° C. Except having set it as 8 micrometers, it carried out similarly to Example 1, and manufactured ten biaxially-stretched polyester film rolls with a film thickness of 100 micrometers, width of 1100 mm, and winding length of 1000 m, and obtained the metallic glossy tone film for decorating.

The metallic glossy tone film for decoration of the present invention has excellent design properties of metallic glossy tone, color tone stability that does not feel a color difference in a large area, anti-scratch resistance, and there is no appearance defect called flow mark, Furthermore, since the outstanding moldability can be achieved, it can be used suitably, for example, for decorating large-area molded members such as large home appliances and automobile parts.

Claims (3)

A biaxially stretched polyester film having a polyester layer A (hereinafter referred to as A layer) and a polyester layer B (hereinafter referred to as B layer), wherein 50 or more layers are alternately laminated in the thickness direction. A metallic glossy tone film for decoration, characterized by satisfying all of (6).
(1) The polyester resin composition which comprises the said B layer contains the residue derived from the diol of ethylene glycol and spiroglycol.
(2) The polyester resin composition constituting the B layer contains a residue derived from dicarboxylic acid of terephthalic acid and cyclohexanedicarboxylic acid.
(3) The absolute reflectance in the wavelength band of 400 to 700 nm is 60% or more.
(4) The color difference ΔE within 1000 mm square is less than 2.0.
(5) The stretching stress at 150 ° C. is 80 N or less.
(6) The outermost layer is the A layer, and the thickness of the outermost layer A layer is 1 μm or more and 15 μm or less. A decorative part obtained by laminating the decorative metallic glossy film according to claim 1 on glass. Home appliances comprising the decorative part according to claim 2.

Images