JP2018054800A - Thermoplastic resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal free thermoplastic resin film with high reflection of visible light and a large coloring in front vision which has remarkable color saturation change with a small angle change.SOLUTION: The thermoplastic resin film is characterized in that: an average reflectance in a wavelength band of 400-750 nm measured at an incident angle of 12° is 30% or more; and the color tone value (a[12°],b[12°]), (a[30°],b[30°]) which is calculated using a calculation formula prescribed in JIS Z 8781, the spectral reflectance measured at incident angles of 12° and 30°, satisfies the following formula (i): formula (i) √{(a[12°]-a[30°])+(b[12°]-b[30°])}≥25.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin film and an anti-counterfeit sheet using the same.

  Films that change color depending on the viewing angle may be used for home appliances, art and craft decorations, and anti-counterfeit sheets. In recent years, in order to produce various expressions, a film having a highly accurate color change pattern is required.

  As a typical method for obtaining a film whose color changes depending on the viewing angle, there is one using an embossed hologram technique. By applying fine optical unevenness to the film surface, it becomes possible to change the color to iridescent depending on the viewing angle, but the construction method is complicated and there are problems in cost and mass productivity.

  As another means for achieving a film whose color changes depending on the angle, a hologram sheet is proposed in which a pseudo hologram is formed by screen printing, the pattern changes depending on the observation angle, and the manufacturing process is simplified (see Patent Document 1). ). In addition, there is known an optical interference multilayer film in which a large number of two kinds of resins having different refractive indexes are alternately stacked and a specific wavelength is reflected by structural optical interference between layers. In this method, a multilayer laminated film is proposed in which the wavelength of reflected light is designed to be close to the primary color of light by selective wavelength reflection, and the reflection peak wavelength is greatly shifted with respect to the incident angle ( Patent Document 2).

JP 2014-12388 A JP 2005-59332 A

The hologram sheet described in Patent Document 1 has a convex curved surface by printing halftone dots twice on a vapor-deposited paper or the like having a halftone underprint layer on the surface, changing the angle in the range of 0.2 to 1 °. A pattern of pseudo-hologram is formed by forming dots of the above-ground printing. However, in order to realize high reflection, vapor deposition paper, mirror ink, or the like is required for the base material. Therefore, there is a problem that cannot be applied to a member that contains a metal and requires recyclability and electromagnetic wave transmission.
In the method described in Patent Document 2, although the color tone change due to the angle is large, reflection in a narrow band results in a color tone close to a single color, and a high-quality feeling or counterfeit due to realization of a deep color tone and high reflection in the visible light band. There was a problem that the expression of the unique color necessary for prevention could not be achieved.

  Accordingly, the present invention provides a thermoplastic resin film that solves the above-described problems of the prior art, highly reflects visible light, has a large coloration when viewed from the front, and has a remarkable saturation change with a slight angle change. It is in.

The present invention employs the following means in order to solve such problems. That is,
A color tone calculated using a calculation formula stipulated in JISZ8781 with an average reflectance of 30% or more in a wavelength band of 400 to 750 nm measured at an incident angle of 12 °, and a spectral reflectance measured at an incident angle of 12 ° and 30 °. Thermoplastic resin characterized by values (a ^* [12 °], b ^* [12 °]) and (a ^* [30 °], b ^* [30 °]) satisfying the following formula (i) the film.
Formula (i) √ {(a ^* [12 °] −a ^* [30 °]) ² + (b ^* [12 °] −b ^* [30 °]) ² } ≧ 25
(The value in [] indicates the measurement incident angle)

  According to the present invention, it is possible to obtain a thermoplastic resin film that highly reflects visible light, has a large coloration when viewed from the front, and has a remarkable saturation change with a slight angle change.

The figure which shows the design layer thickness of Examples 1-6 and Comparative Examples 1-5 The figure which shows the design layer thickness of Example 7 The figure which shows the design layer thickness of Example 8 and 9 The figure which shows the design layer thickness of Example 10 The figure which shows the design layer thickness of the comparative example 6 An example of a configuration diagram of a feed block used in the present invention Configuration diagram of slit plate and slit Cross-sectional configuration diagram of slit

The thermoplastic resin film of the present invention needs to have an average reflectance of 30% or more in a wavelength band of 400 to 750 nm measured at an incident angle of 12 ° determined by a measurement method described later. It is preferably 40% or more, and more preferably 50% or more. The incident angle in the present invention is an angle parallel to the film thickness direction of 0 ° and an angle perpendicular to the film thickness direction of 90 °. The reflectivity of a film using interference reflection generally tends to be higher when the incident angle is close to 90 °. Therefore, when the average reflectance in the wavelength band 400-750 nm measured at an incident angle of 12 ° is 30% or more, a film having a high reflectance at a wide angle can be obtained. And when the average reflectance in the wavelength band of 400 to 750 nm is high, the saturation becomes high, so that the change in saturation when the incident angle changes is likely to increase. When the average reflectance measured at an incident angle of 12 ° is less than 30%, the saturation is low, and the change in saturation when the incident angle changes is small. The saturation is a numerical value indicating the size of the color represented by √ (a ^{* 2} + b ^{* 2} ).

The thermoplastic resin film of the present invention has a color tone value (a ^* [12 °) calculated using a calculation formula that prescribes the spectral reflectance measured at an incident angle of 12 ° and 30 ° determined by a measurement method described later in JISZ8781. ], B ^* [12 °]), (a ^* [30 °], b ^* [30 °]) must satisfy the following formula (i).
Formula (i) √ {(a ^* [12 °] −a ^* [30 °]) ² + (b ^* [12 °] −b ^* [30 °]) ² } ≧ 25
In the present invention, √ {(a ^* [12 °] −a ^* [30 °]) ² + (b ^* [12 °] −b ^* [30 °]) ² } is hereinafter expressed as ΔC ^* (angle-dependent saturation). May be called difference. ΔC ^* is an index representing the degree of change in saturation depending on the viewing angle (angle-dependent saturation difference). By setting ΔC ^* within the above range, the color tone changes with a slight change in the incident angle of light, and it is possible to produce colors and high-class feelings that cannot be achieved with existing technologies, and can be applied to anti-counterfeit sheets. It is possible to achieve a unique color. ΔC ^* is preferably 30 or more, more preferably 40 or more, and preferably 90 or less. When ΔC ^* is less than 25, the angle dependency of the saturation change becomes small, and the color change can be achieved with the existing technology.

In the thermoplastic resin film of the present invention, it is preferable that a ^* [12 °, b ^* [12 °]) at an incident angle of 12 ° determined by a measurement method described later satisfy the following formula (ii).
Formula (ii) √ (a ^* [12 °] ² + b ^* [12 °] ² ) ≧ 30
In the present invention, √ (a ^* [12 °] ² + b ^* [12 °] ² ) may be hereinafter referred to as C ^* (saturation). By setting C ^* to 30 or more, a film having a large color and a high design property can be obtained. C ^* is preferably 40 or more, and more preferably 50 or more. When C ^* is less than 30, high designability cannot be achieved, and even when the incident angle is changed, the change in ΔC ^* may be small. The spectral reflectance is measured at an incident angle of about 10 °, which is the minimum measurement angle, and the saturation is closest to that seen from the front. In the present invention, the measured value at the incident angle of 12 ° is viewed from the front. It may be a numerical value when doing.

  The thermoplastic resin film of the present invention preferably has a haze of 0.1% to 2.0%. Preferably they are 0.1% or more and 1.5% or less, More preferably, they are 0.1% or more and 1.0% or less. If the haze of the film exceeds 2.0%, the visibility of the printed matter may be lowered when a printed layer is provided on the back side of the film sheet.

  In the thermoplastic resin film of the present invention, it is preferable that delamination does not occur in an adhesion test by a cross-cut method according to JISK5600. When delamination occurs by the cross-cut method, delamination may occur due to stress at the time of cutting in the film processing step, and the processing yield may be reduced.

The thermoplastic resin film of the present invention, _R 80 obtained by the following formula from the reflectance in the wavelength band 400-750nm, measured at an incident angle of 12 ° as determined by a measuring method described later (iii), formula (iv), R seeking _20, lowest wavelength band of low wavelength side lambda ₈₀ wavelengths exceeding the reflectivity of R _80, lower wavelength a wavelength closest to lambda ₈₀ that exceeds the reflectance R ₂₀ in the low-wavelength-side lambda ₈₀ low-wavelength-side a side lambda _20, the low-wavelength-side lambda ₈₀ - low-wavelength-side ₈₀ the low-wavelength-side lambda the wavelength band of lambda ₂₀ 1-? _20, the high wavelength side lambda ₈₀ wavelength exceeding reflectance _{R 80} at the highest wavelength band, high a wavelength closest to lambda ₈₀ that exceeds the reflectance R ₂₀ from wavelengths lambda ₈₀ with high wavelength side and high wavelength side lambda _20, the high wavelength side lambda _{20 -} higher wavelength side lambda ₂₀ wavelength bands of high wavelength side lambda ₈₀ When −λ ₈₀ is set, the lower wavelength side λ ₈₀ −λ The wavelength band of ₂₀ and the high wavelength side λ ₂₀ -λ ₈₀ is preferably 65 nm or less. More preferably, it is 55 nm or less, More preferably, it is 45 nm or less. When the values of the low wavelength side λ ₈₀ -λ ₂₀ and the high wavelength side λ ₂₀ -λ ₈₀ are decreased, the rise of reflection reaching the high reflection region from the low reflection region in the wavelength band 400-750 nm and the reflection The falling of the reflection reaching the low reflection region from the high region changes sharply at short wavelength intervals. Since the rise and fall of the reflection become sharp, only the target wavelength can be selectively reflected, and ΔC ^* with a slight change in the incident angle becomes large.
Formula (iii) R ₈₀ = {(maximum reflectance−minimum reflectance) × 0.8} + minimum reflectance (%)
Formula (iv) R ₂₀ = {(maximum reflectance−minimum reflectance) × 0.2} + minimum reflectance (%)
The thermoplastic resin film of the present invention has a layer composed of a thermoplastic resin A (hereinafter referred to as “A layer”) and a layer composed of a thermoplastic resin B layer containing an amorphous resin (hereinafter referred to as “B layer”). It is preferable that a total of 200 or more layers are alternately laminated in the direction. More preferred is a structure in which 300 layers or more are alternately laminated in the thickness direction, and still more preferred is a structure in which 400 layers or more are alternately laminated in the thickness direction. In the case of a laminate of less than 200 layers, only some wavelengths of visible light are reflected, and reflection close to a single color may result in failure to achieve high designability due to color depth and high reflection.

In the thermoplastic resin film of the present invention, the thickness of the outermost layer on both sides is preferably 1 μm or more and 10 μm or less. More preferably, it is 2 μm or more and 7 μm or less. When the thickness is less than 1 μm, stacking unevenness due to stacking failure occurs, the reflection rising and falling bands become wide, and ΔC ^* may be reduced. When the thickness exceeds 10 μm, delamination may easily occur in the vicinity of the surface thick film layer.

The thermoplastic resin film of the present invention preferably has one or more layers having a thickness of 2 μm or more and 6 μm or less as an inner layer. More preferably, it is 3 μm or more and 4 μm or less. If the thickness is less than 1 μm, uneven stacking due to stacking failure may occur, and the target optical performance may not be obtained, and ΔC ^* may be reduced. When it exceeds 6 μm, delamination may easily occur near the inner thick film layer.

In the thermoplastic resin film of the present invention, in a thin film layer having a layer thickness of less than 1 μm, the thickness difference between adjacent layers of the A layer and the B layer continuously increases or decreases monotonously within a range of 50 nm or less. It is preferable to have two or more inclined structures. If it does not have an inclined structure of two or more steps, a slight stacking fault occurs in a very small part of the layer, and if it deviates from the design value, there is no layer of the same thickness in the other part. In some cases, the rising and falling bands are widened and ΔC ^* cannot be reduced. The figure which shows the design layer thickness is demonstrated as an example of the preferable layer structure of the thermoplastic resin film in this invention. FIG. 1 shows a film in which layers composed of two types of thermoplastic resins (hereinafter also referred to as “resin A” and “resin B”) are alternately laminated in the thickness direction. FIG. The layer thickness corresponds only to the integer layer number in the figure, the A layer made of the crystalline thermoplastic resin A corresponds to the odd number, and the B layer made of the thermoplastic resin B containing the amorphous resin is Corresponds to an even number. The thick film layer is preferably formed of an A layer made of resin A which is a crystalline resin. The same applies to FIG. In addition, the layer structure changes from decreasing to increasing, and the portion where increasing to decreasing tends to cause a stacking failure, and the rising and rising bands of reflection are widely caused. Therefore, the thickness of the inner layer having a thickness of 2 μm to 6 μm. By providing the film layer at the above location, the thick film layer can absorb the shear stress generated in the extrusion process at the time of manufacture, which causes the stacking failure. When the inner thick film layer is less than 2 μm, it is possible to suppress the stacking fault because the layer configuration changes from decrease to increase, and the shear stress due to stacking fault at the location where the increase or decrease changes is not sufficient. In addition, since the reflection of light at a specific wavelength is different from the design value, ΔC ^* with a slight angle change may be small. When the inner thick film layer exceeds 6 μm, the elastic modulus is different between the thick film layer made of the crystalline resin A and the portion other than the thick film layer. Therefore, if shear stress is applied in the thickness direction during cutting in processing, the thick film layer Stress may concentrate in the vicinity, and delamination may occur easily. FIG. 3 shows a structure with 349 layers in FIG. 1, and FIG. 4 shows a structure with 249 layers in FIG. FIG. 5 shows a structure in which the number of layers is 149 in FIG. In some cases, the average reflectance in the band of 400 to 700 nm cannot be increased to 30% or more.

  Further, in the present invention, for convenience, the layer thickness configuration of FIGS. 1, 3, 4 and 5 is referred to as a two-step inclined structure, and the layer thickness configuration of FIG. 2 is referred to as a three-step inclined structure. Here, the “two-step inclined structure” referred to in the present invention refers to a structure that can be approximated by two monotonically increasing curves and / or monotonically decreasing curves.

  The two types of resins, the crystalline thermoplastic resin A and the thermoplastic resin B containing an amorphous resin in the present invention, may be a copolymer or a mixture of two or more resins. Among these, it is particularly preferable to use a polyester resin. The crystallinity here means that the heat of fusion is 5 J / g or more in differential scanning calorimetry (DSC). On the other hand, “amorphous” means that the heat of fusion is similarly less than 5 J / g.

  As the polyester resin, a polyester obtained by polymerization from a monomer mainly composed of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol is preferable. Here, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′- Examples thereof include diphenyl dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl sulfone dicarboxylic acid, and the like. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid and ester derivatives thereof. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid having a high refractive index are preferable. Only one kind of these acid components may be used, or two or more kinds may be used in combination, and further, an oxyacid such as hydroxybenzoic acid may be partially copolymerized. Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-hexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4- Hydroxyethoxyphenyl) propane, isosorbate, spiroglycol and the like. Of these, ethylene glycol is preferably used. These diol components may use only 1 type and may use 2 or more types together.

  Among the polyesters, polyethylene terephthalate and copolymers thereof, polyethylene naphthalate and copolymers thereof, polybutylene terephthalate and copolymers thereof, polybutylene naphthalate and copolymers thereof, and polyhexamethylene terephthalate and copolymers thereof. It is preferable to use a polymer, polyhexamethylene naphthalate, a copolymer thereof, and the like.

  As a preferable combination of the resin A and the resin B selected from thermoplastic resins, it is preferable to use a resin containing the same basic skeleton as one of the resins. Here, the “basic skeleton” referred to in the present invention refers to a repeating unit constituting a resin. For example, when one resin is polyethylene terephthalate, ethylene terephthalate is the basic skeleton. Examples of the polymer include a polymer (copolymer) composed of an ethylene terephthalate unit and a cyclohexane 1,4-dimethylene terephthalate unit. As another example, when one resin is polyethylene, ethylene is a basic skeleton. When resins having the same basic skeleton are used, problems such as delamination are less likely to occur in the production of a thermoplastic resin film.

  As the crystalline thermoplastic resin A, it is preferable to use polyethylene terephthalate or polyethylene naphthalate from the viewpoints of stamping resistance (dentation resistance) and stiffness of the film itself.

  As an amorphous resin of the thermoplastic resin B containing an amorphous resin, from the viewpoint of suppressing an increase in refractive index, it contains isophthalic acid, naphthalenedicarboxylic acid, diphenyl acid, cyclohexanedicarboxylic acid, or spiroglycol, The copolymer of the resin A containing cyclohexanedimethanol, bisphenoxyethanol fluorene, and bisphenol A component is preferably mixed with the resin A or used alone.

  FIG. 6 shows an example of a feed block which is a preferred embodiment for obtaining a thermoplastic resin film having an inclined structure in the present invention. The feed block is a laminating apparatus for laminating two kinds of resins A and B, and details thereof will be described below. In FIG. 6, member plates 6 to 16 are stacked in this order to form a feed block 17.

  The feed block 17 in FIG. 6 is derived from the resin introduction plates 7, 9, 11, 13, 15 and has five resin introduction ports. For example, the resin A is fed from the introduction ports 18 of the resin introduction plates 7, 11, 15. The resin B is supplied from the introduction port 18 of the resin introduction plates 9 and 13. Then, the slit plate 8 receives the resin A from the resin introduction plate 7 and the resin B from the resin introduction plate 9, and the slit plate 10 receives the resin A from the resin introduction plate 11 and the resin B from the resin introduction plate 9. The slit plate 12 receives the resin A from the resin introduction plate 11 and the resin B from the resin introduction plate 13. The slit plate 14 receives the resin A from the resin introduction plate 15 and the resin B from the resin introduction plate 13. Will receive.

Here, the type of resin introduced into each slit plate is determined by the positional relationship between the bottom surface of the liquid reservoir 19 in the resin introduction plates 7, 9, 11, 13 and 15 and the end of each slit in the slit plate. The That is, as shown in FIG. 6, the ridgeline 20 at the top of each slit in the slit plate has an inclination with respect to the thickness direction of the slit plate (FIGS. 7B and 7C). However, as shown in FIG. 7A, the slit width for forming the thick film layer located at both ends of the slit plate is 2 from the viewpoint of preventing the thin film layer from being broken. It is necessary to be more than twice. Here, the slit width forming another thin film layer is an average value of the widths of the slit portions forming the thin film layer in at least one slit plate. More preferably, it is 3 times or more. In particular, the slit corresponding to each outermost layer portion of the film of the slit plate 8 and the slit plate 14 needs to be 10 times or more the slit width into which the resin A is introduced and other thin film layers are formed. At this time, by continuously arranging the slits into which the resin A flows, the widths can be totaled to be 10 times or more the slit width for forming another thin film layer. In this way, by providing a thick film layer at the location where the resin fed from the feed block merges and at the location where the resin block wall meets the boundary with the wall surface of the pipe, the change in the layer thickness distribution immediately after merging In addition, it is possible to prevent fluctuations in the resin velocity in the multilayer flow near the pipe, so that the bandwidth of the rise and fall of the reflection is narrow and the ΔC ^* Can be obtained.

  As shown in FIG. 8, the height of the bottom surface of the liquid reservoir 19 in the resin introduction plates 7, 9, 11, 13, and 15 (13 and 15 are omitted from FIG. 8 because they are repetitive structures) It is located at a height between the upper end 21 and the lower end 22 of the ridge line 20. Thus, resin is introduced from the liquid reservoir 19 of the resin introduction plates 7, 9, 11, 13, and 15 from the side where the ridge line 20 is raised (23 in FIG. 8), but the ridge line 20 is lowered. From the side, the slit is sealed and no resin is introduced. Thus, since the resin A or B is selectively introduced for each slit, the flow of the resin having a laminated structure is the slit plates 8, 10, 12, and 14 (12 and 14 are omitted because they are repetitive structures). It is formed inside and flows out from the outlet 24 below the slit plates 8, 10, 12, 14.

  As the shape of the slit, it is preferable that the slit area on the side where the resin is introduced is not the same as the slit area on the side where the resin is not introduced. With such a structure, the flow rate distribution on the side where the resin is introduced and the side where the resin is not introduced can be reduced, so that the laminating accuracy in the width direction is improved. Further, (slit area on the side where no resin is introduced) / (slit area on the side where the resin is introduced) is preferably 0.2 or more and 0.9 or less. More preferably, it is 0.5 or less. Moreover, it is preferable that the pressure loss in a feed block will be 1 Mpa or more. Moreover, it is preferable that the slit length (the longer one of the slit lengths in the Z direction in FIG. 6) is 20 mm or more. On the other hand, the gap width of the slit is preferably 0.3 mm or more from the viewpoint of processing accuracy, more preferably 0. It is 5 mm or more and 3 mm or less.

  Thus, by adjusting the width and length of the slit, it is possible to control the thickness of each layer and obtain a thermoplastic resin film having an inclined structure. Further, in each slit, the slit gap width is preferably in the range of −3% to + 3% of the target value. More preferably, it is in the range of -2% to + 2%. When the slit gap width is in the range of −3% to + 3% of the target value, local increase / decrease in the density of the layer thickness can be prevented. Note that the slit is preferably manufactured by wire electric discharge machining from the viewpoint of requiring high machining accuracy in which the width and length are finely adjusted.

  It is also preferable to have a manifold portion corresponding to each slit plate. Since the manifold section makes the flow velocity distribution in the width direction (Y direction in FIG. 6) inside the slit plate uniform, the lamination ratio in the width direction of the laminated films can be made uniform, and a large area film However, it becomes possible to laminate with high accuracy, and the reflectance in the film width direction can be controlled with high accuracy. Moreover, it is preferable that the 2nd manifold which has a larger dimension of a lamination direction than a slit gap | interval is provided in all the slit width directions in the part connected to each slit from the said manifold. The second manifold is preferably at least twice the slit gap. In addition, it is preferable that the second manifold is inclined in the downstream direction as it is separated from the manifold of the resin introduction plate communicating with the slit. By adopting such a structure, the molten material can easily flow into the slit far from the manifold of the resin introduction plate, and the difference in flow rate between the near side and the far side of the first manifold of the slit becomes small. The flow rate of the molten material becomes uniform. More preferably, the resin is supplied from one liquid reservoir to two or more slit plates. In this way, for example, even if there is a flow distribution in the width direction slightly inside the slit plate, because it is further laminated in the merging device described below, the lamination ratio is made uniform in total, It is possible to reduce unevenness in the high-order reflection band.

  The polymer passing through the slit is generally represented by the formula (v).

That is, assuming that the pressure in the liquid reservoir is uniform and the pressure drop ΔP is constant, the flow rate Q corresponding to one layer thickness can be easily adjusted by adjusting one slit size. it can. In this apparatus, since the thickness of each layer can be adjusted by a slit shape (length, width), it is possible to achieve an arbitrary layer thickness. For example, a method for achieving the structure as shown in FIG. 1 will be described. In this case, the slit plate has a structure of two sheets, and the slit length of each slit plate has a distribution of monotonically increasing and monotonically decreasing slit lengths, and between adjacent slit plates (here monotonic). Distribution of length and width of at least 10 or more slits arranged at the front and back, respectively, centering on the slits forming the thick film layer that becomes the joint of the layers at the points where the increase and decrease or monotonous decrease and increase occur) Is achieved by designing to be the same before and after.

Q: Resin flow rate t: Slit width W: Slit depth μ: Resin viscosity L: Slit length ΔP: Pressure drop The resin that flows out from each slit plate is a merging device arranged just below the feed block in FIG. Are merged as one laminated flow. Thereafter, the molten resin flow is filled in the manifold portion inside the T die, further widened, and then extruded into a sheet form from the die slit. At this time, the sheet width direction dimension of the arbitrary cross section perpendicular to the flow path direction in the flow path connecting the feed block and the base is W, the sheet thickness direction dimension is T, and the sheet width direction dimension of the discharge port of the base is And Wd, and L being the minimum sheet thickness direction dimension of the outermost layer of the laminate, it is preferable that both the relations of formulas (vi) and (vii) are satisfied.

In order for the thermoplastic resin film to reflect only the design wavelength in the wavelength band of 400 to 750 nm, it is necessary to design the layer thickness of each layer based on the following formula (viii). The thermoplastic resin film in the present invention can reflect / transmit light, but the reflectance can be controlled by the refractive index difference between the resin A and the resin B and the number of layers.
Formula (viii) 2 × (na · da + nb · db) = λ
na: In-plane average refractive index of a layer made of crystalline thermoplastic resin A nb: In-plane average refractive index of a layer made of thermoplastic resin B containing an amorphous resin da: Layer thickness of a layer made of resin A (Nm)
db: Layer thickness of the layer made of resin B (nm)
λ: main reflection wavelength (primary reflection wavelength)
The in-plane average refractive index (n _a , n _b ) of the A layer and the B layer is 5 mm (width direction) × 20 mm (longitudinal direction) × 0.5 mm (thickness direction) of a single film oriented film. It is obtained by measuring the refractive index of the film at a temperature of 23 ° C. and a wavelength of 589 nm five times with an Abbe refractometer, and calculating the average value.

  In the thermoplastic resin film of the present invention, in order to make the lamination of the resins A and B as designed, it is necessary to control the lamination unevenness immediately after the resin A and the resin B merge at the feed block. Resin A and Resin B merged in the feed block have different melt viscosities, so uneven stacking occurs near the interface between Resin A and Resin B, and stacking unevenness grows before the die discharges, resulting in a change in design and layer thickness. However, reflection in a desired wavelength band may not be achieved. In order to achieve high reflection, resin A may be a PET resin, and resin B may be a resin having a low refractive index copolymerized with spiroglycol (SPG) and cyclohexanedicarboxylic acid (CHDC). In a temperature range of 270 to 290 ° C., which is a high melting temperature, the melt viscosity of the resin A may be low, and shear stress caused by the viscosity difference may occur due to the distribution of shear stress in the layer of the resin B. In order to reduce the shear distribution in the layer of the resin B due to the resin A, the viscosity of the resin A is low, and by increasing the viscosity of the resin B, it is preferable because uneven lamination can be suppressed.

  In the thermoplastic resin film of the present invention, the difference between the in-plane average refractive index of the A layer of the thermoplastic resin film and the in-plane average refractive index of the B layer is preferably from 0.055 to 0.120. More preferably, it is 0.060 or more and 0.115 or less. When the difference in the in-plane average refractive index is less than 0.055, sufficient reflectance may not be obtained, and high designability may not be achieved.

  In the thermoplastic resin film of the present invention, it is preferable that an easy-adhesion layer comprising an acrylic / urethane copolymer resin and two or more kinds of crosslinking agents is provided on at least one surface of the thermoplastic resin film. When a print layer or a hard coat layer is applied to a thermoplastic resin film, the adhesion at the interface may be reduced if an easy adhesion layer is not provided on the treated surface. Moreover, when applying a printing layer and a hard-coat layer on both surfaces of a thermoplastic resin film, it is preferable that the easily bonding layer is provided in both surfaces.

  As the acrylic / urethane copolymer resin constituting the easy-adhesion layer preferably used in the present invention, an acrylic monomer is, for example, an alkyl acrylate (the alkyl group is methyl, ethyl, n-propyl, n-butyl, isobutyl, t- Butyl, 2-ethylhexyl, cyclohexyl, etc.), 2-hydroxylethyl acrylate, 2-hydroxylethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and other hydroxy group-containing monomers, acrylamide, methacrylamide, N-methyl methacrylamide N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate Amino group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and other glycidyl group-containing monomers, acrylic acid, methacrylic acid and their salts (sodium salts, potassium salts, ammonium salts, etc.) carboxyl groups or monomers containing such salts, etc. Can be used. Moreover, as the urethane component in the present invention, a resin obtained by reacting a polyhydroxy compound and a polyisocyanate compound by a known urethane resin polymerization method such as emulsion polymerization or suspension polymerization can be used. Examples of the polyhydroxy compound constituting the urethane component include polyethylene glycol, polypropylene glycol, polyethylene / polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, poly Caprolactone, polyhexamethylene adipate, polyhexamethylene sebacate, polytetramethylene adipate, polytetramethylene sebacate, trimethylolpropane, trimethylolethane, pentaerythritol, polycarbonate diol, glycerin and the like can be used.

  As the crosslinking agent constituting the easy-adhesion layer in the present invention, it is preferable to copolymerize a crosslinkable functional group, for example, a melamine crosslinking agent, an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, or a methylolation. Alternatively, alkylolized urea crosslinking agents, acrylamide crosslinking agents, polyamide crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, various silane coupling agents, various titanate coupling agents, and the like can be used. Further, from the viewpoint of heat-and-moisture resistance to the hard coat layer and the silicone-based adhesive layer, it is preferable to use two or more types of crosslinking agents. Specifically, at least one of the crosslinking agents is an oxazoline-based crosslinking agent or a carbodiimide. It is preferable to use a system crosslinking agent.

  Furthermore, since only the components of the easy-adhesion layer are easily charged, as a result, foreign matters may be mixed during processing due to static electricity, resulting in a problem of appearance defects. Therefore, it is preferable that the component of the easily adhesive layer contains a conductive polymer from the viewpoint of antistatic. As the conductive polymer, polypyrrole, polyaniline, polyacetylene, polythiophene vinylene, polyphenylene sulfide, poly-p-phenylene, polyheterocycle vinylene, particularly preferably (3,4-ethylenedioxythiophene) (PEDOT) is there.

  By providing a hard coat layer on the surface of the thermoplastic resin film of the present invention, the thermoplastic resin film can be prevented from being damaged, and scratch resistance can be imparted. However, for applications that do not require a hard coat layer in terms of cost, it is not always necessary to provide a hard coat layer.

  As the hard coat layer, for example, acrylic resins, urethane resins, melamine resins, organic silicate resins, silicone resins, and the like can be used. Among these, from the viewpoints of hardness, durability and productivity, silicone resins and acrylic resins are preferable, acrylic resins are more preferable, and active ray curable acrylic resins are most preferable.

  In the composition of the hard coat layer, various additives can be blended as necessary within a range not impairing the effects of the present invention. For example, stabilizers such as antioxidants, light stabilizers, ultraviolet absorbers, surfactants, leveling agents, antistatic agents, and the like can be used. The thickness of the hard coat layer in the present invention is determined according to the use, but is usually preferably 0.1 μm or more and 30 μm or less, and more preferably 1 μm or more and 15 μm or less. When the thickness of the hard coat layer is less than 0.1 μm, even if the composition of the hard coat layer is sufficiently cured, the film thickness is too thin, so that the surface hardness is low and the surface may be easily damaged. When the thickness of the hard coat layer exceeds 30 μm, the cured film may easily crack due to stress such as bending.

  In the thermoplastic resin film of the present invention, in addition to the easy-adhesion layer, hard coat layer and antistatic layer, an abrasion resistant layer, an antireflection layer, a color correction layer, an ultraviolet absorbing layer, a printing layer, a metal layer, a transparent conductive layer Functional layers such as a gas barrier layer, a hologram layer, a release layer, an adhesive layer, an emboss layer, and an adhesive layer may be formed.

  Next, although an example of the preferable manufacturing method of the thermoplastic resin film of this invention is demonstrated below, it is not restrict | limited by this.

  First, two types of resins A and B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to each of two extruders. In each extruder, the resin melted by heating to a temperature equal to or higher than the melting point makes the amount of resin extruded uniform with a gear pump or the like, and removes foreign matter or modified resin through a filter or the like. Resin A and resin B sent out from different flow paths using two extruders are sent into the multilayer laminating apparatus. As a multilayer laminating apparatus, it is desirable to use a feed block including at least two members having a large number of fine slits separately. When such a feed block is used, the apparatus does not become extremely large, so that foreign matter due to thermal deterioration is small, and even when the number of layers is extremely large, it is possible to stack with high accuracy. Also, the stacking accuracy in the width direction is significantly improved as compared with the prior art. It is also possible to form an arbitrary layer thickness configuration.

  When the inclined structure has two or more steps, the change from the thin layer to the thick layer or the change in the layer thickness from the thick layer to the thin layer becomes very steep. In the present invention, a feed block including at least two members having a large number of fine slits is used. However, the layer thickness distribution changed immediately after merging at the location where the resins fed from the separate feed blocks merged, which was a major factor in varying the color tone in the width direction. Therefore, it is necessary to adjust the flow rate so that the lamination ratio becomes 0.7 to 1.3 so that the flow rate of the resin A and the resin B does not change greatly in the portion corresponding to the layer having a thickness of 1 μm or less in the laminated film. It is. In addition, the resin A has a low viscosity and the resin B has a high viscosity so that the unevenness of the lamination is small so that the resin B, which has a higher viscosity than the resin A in the molten state, does not generate distortion due to the shear stress difference in the layer. Thus, a desired layer thickness distribution is obtained. Furthermore, since the resin speed near the pipe decreases due to the influence of the wall surface of the pipe in the path from the feed block to the base, the film lamination accuracy is further deteriorated due to the difference in flow velocity between the pipe wall surface and the pipe center. Therefore, by replacing a certain distance between the resin outermost layer part and the resin merging part of the separate feed block with the same polymer, a thermoplastic resin having a narrow wavelength band in which rise and fall of reflection are narrow without breaking the lamination ratio A film can be obtained. At this time, when the outermost thick film layer on both sides of the laminated film is the resin A, the layer made of the resin A corresponds to the outer thick film layer (the outermost layer on both sides). Moreover, it is preferable that the resin used for the inner thick film layer is a highly crystalline resin in order to improve the anti-scratch resistance. If the inner thick film layer is less than 2 μm, the suppression of the change in the layer thickness distribution at the merging portion is not sufficient, and it is necessary that the thickness is 2 μm or more. In adjusting the thickness of the thick film layer, it is preferable to adjust each flow rate corresponding to the thickness of the corresponding layer by the gap between the slits. In this case, the gap accuracy of each slit gap is preferably ± 10 μm or less. By using such a special feed block, it is possible to obtain a thermoplastic resin film that forms an inclined structure of two or more stages with high accuracy.

  The molten laminate formed in the desired layer configuration in this way is then formed into a desired shape with a die and then discharged. And the sheet | seat laminated | stacked in the multilayer discharged | emitted from die | dye is extruded on rotary cooling bodies, such as a casting drum, and is cooled and solidified, and a casting film (non-stretched film) is obtained. At this time, it is preferable to use a wire-like, tape-like, wire-like, or knife-like electrode to be brought into close contact with a rotating cooling body such as a casting drum by an electrostatic force and rapidly solidify. Also preferred is a method in which air is blown out from a slit-like, spot-like or planar device and brought into close contact with a rotating cooling body such as a casting drum, or rapidly cooled and solidified by being brought into close contact with the rotating cooling body with a nip roll.

  The casting film (unstretched film) thus obtained is preferably biaxially stretched as necessary. Biaxial stretching refers to stretching in the longitudinal direction and the width direction. Stretching may be performed sequentially in biaxial directions or simultaneously in two directions. Further, the film may be re-stretched in the longitudinal direction and / or the width direction. In particular, in the present invention, it is preferable to use simultaneous biaxial stretching from the viewpoint of suppressing in-plane orientation differences and from the viewpoint of suppressing surface scratches.

  First, the case of sequential biaxial stretching will be described. Here, the stretching in the longitudinal direction refers to stretching for imparting molecular orientation to the film in the longitudinal direction. Usually, the stretching is performed by a difference in the peripheral speed of the roll. You may carry out in multiple steps using a roll pair of books. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for a thermoplastic resin film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature of the resin which comprises a thermoplastic resin film-glass transition temperature +100 degreeC is preferable.

  When providing an easily bonding layer in the thermoplastic resin film of this invention, the method of coating and laminating | coating a coating agent is preferable. As a method of coating the coating agent, a method of coating in a process separate from the polyester film manufacturing process in the present invention, a so-called off-line coating method, and an easy adhesion by performing coating during the polyester film manufacturing process of the present invention. There is a so-called in-line coating method in which the layers are laminated at once. It is preferable to adopt an in-line coating method from the viewpoint of cost and uniform coating thickness, and the solvent of the coating liquid used in that case is preferably an aqueous system from the viewpoint of environmental pollution and explosion-proof property, and water is used. It is the most preferred embodiment to use.

  When laminating the easy-adhesion layer by in-line coating, a coating material that forms the easy-adhesion layer is continuously applied to the uniaxially stretched polyester film. As a coating method of a coating (water-based coating) using water as a solvent, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

  Before applying the water-based coating, it is preferable to subject the surface of the polyester film to a corona discharge treatment or the like. This is because the adhesion between the polyester film and the coating material is improved and the coating property is also improved.

  The easy-adhesive layer has a crosslinking agent, antioxidant, heat-resistant stabilizer, anti-glare stabilizer, ultraviolet absorber, organic easy-to-lubricant, pigment, dye, organic or inorganic as long as the effect of the invention is not impaired. You may mix | blend particle | grains, a filler, surfactant, etc.

  Subsequent stretching in the width direction refers to stretching for imparting molecular orientation in the width direction of the film, usually using a tenter, transporting the film while holding both ends with clips, and applying heat to the film. After preheating, the film is stretched in the width direction. The aqueous coating applied just before the tenter is dried during this preheating. The stretching ratio varies depending on the type of resin, but usually 2 to 15 times is preferable, and 2 to 7 times is particularly preferable when polyethylene terephthalate is used for any of the resins constituting the polyester film in the present invention. . Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises the polyester film in this invention are preferable. The biaxially stretched polyester film is preferably subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter in order to impart flatness and dimensional stability. 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 use a relaxation process etc. together in the case of annealing from heat processing as needed.

  Next, the case of simultaneous biaxial stretching will be described. In the case of simultaneous biaxial stretching, the coating material which comprises an easily bonding layer is apply | coated continuously to the obtained cast film. As a coating method of a coating (water-based coating) using water as a solvent, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, or the like can be used.

  Before applying the aqueous coating material, it is preferable to subject the surface of the thermoplastic resin film in the present invention to corona discharge treatment or the like. This is because the adhesion between the polyester film and the coating material is improved and the coating property is also improved. Next, the cast film (non-stretched film) coated with the coating agent is guided to the simultaneous biaxial tenter, and conveyed while holding both ends of the film with clips, and stretched in the longitudinal and width directions simultaneously and / or stepwise. To do. 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. The stretching magnification varies depending on the type of resin, but usually, the area magnification is preferably 6 to 50 times, and the area magnification is particularly preferably 8 to 30 times. 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 of the resin which comprises a polyester film-glass transition temperature +120 degreeC is preferable. 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 impart flatness and dimensional stability. In this heat treatment, in order to suppress the distribution of the main orientation axis in the width direction, it is preferable to perform a relaxation treatment instantaneously 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. It is preferable to perform relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone.

  The thermoplastic resin film of the present invention thus obtained highly reflects visible light, is highly colored when viewed from the front, and has a noticeable change in saturation due to a slight angle change. It can be suitably used for decorations such as decorations and home appliances, and decorative films used for art and crafts. Moreover, since the thermoplastic resin film of the present invention achieves high visible light reflectivity and saturation change with a slight angle change without using metal, the thermoplastic tax resin film of the present invention was used. Since the anti-counterfeit sheet is excellent in recyclability and electromagnetic wave permeability, it can be suitably used for various IC cards and securities.

  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) Layer structure and layer thickness of film Using a transmission electron microscope (H-7100FA type, manufactured by Hitachi, Ltd.) with a sample cut out by a microtome, the cross section of the film was measured at an acceleration voltage of 75 kV. The film was observed at a magnification of 1,000,000, and the cross-sectional portion was photographed to measure the layer structure and the layer thickness. Moreover, the total thickness of each layer was made into the laminated film whole thickness. In order to obtain a high contrast, the sample was stained with RuO ₄ .

  A specific method for obtaining the layer structure and layer thickness of the film will be described. About 40,000 times TEM photographs were captured with CanonScan D123U (manufactured by Canon Inc.) at an image size of 729 dpi. The image was saved in JPEG format, and then the JPEG file was opened and image analysis was performed using image processing software (sales company Planetron Co., Ltd., Imagc-Pro Plus ver. 4). In the image analysis processing, in the vertical thick profile mode, the relationship between the average brightness in the region sandwiched between the two lines in the thickness direction and the width direction was read as numerical data. Using spreadsheet software (Excel2010), the position (nm) and brightness data were sampled in sampling step 1 (thinning 1) and subjected to numerical processing of a 5-point moving average. Furthermore, the data obtained by periodically changing the brightness is differentiated, and the maximum and minimum values of the differential curve are read by a VBA (Visual Basic For Applications) program. Calculated as the layer thickness. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated. Of the obtained layer thickness, the thin film layer was a layer having a thickness of less than 1 μm. A group in which the thickness difference between adjacent layers in the A layer and the B layer is continuously monotonously increasing or monotonically decreasing in a range of 50 nm or less is defined as an inclined structure. The inclined structure has a positive or negative inclination in which the square of R becomes 0.90 or more when the relation between the layer number and the layer thickness of each of the A layer and the B layer is approximated by least squares. The two-stage inclined structure and the configuration in FIG. 2 are referred to as a three-stage inclined structure.

(2) 400-750 nm average reflectance The sample of 5 cm square was cut out from the thermoplastic resin film. Subsequently, the relative reflectance in incident angle (PHI) = 12 was measured using the spectrophotometer (The Hitachi, Ltd. make, U-4100 Spectrophotometer). The inner wall of the attached integrating sphere is barium sulfate, and the standard plate is aluminum oxide. The measurement wavelength was 250 nm to 1200 nm, the slit was 2 nm (visible) / automatic control (infrared), the gain was set to 2, and the measurement was performed at a scanning speed of 600 nm / min. The back of the sample was painted black with oil-based ink. Next, the average reflectance in the wavelength band of 400 to 750 nm was calculated. The average reflectance is calculated by calculating the area surrounded by the reflection curve and the wavelength band based on the Simpson method formula using absolute reflectance data for each wavelength of 1 nm, and dividing by the wavelength band width of 350 nm. Thus, the average reflectance was obtained. A detailed explanation of the Simpson method is described in “Numerical calculation method I for electronic computers” (Baifukan) (1965) by Jiro Yamauchi et al.

  The absolute reflectivity at an incident angle Φ = 30 ° was measured under the same conditions as when the incident angle Φ = 12 ° using an angle variable absolute reflectivity accessory device, and the average reflectivity was calculated.

(3) Low wavelength side λ ₈₀ -λ ₂₀ , High wavelength side λ ₂₀ -λ ₈₀
A 5 cm square sample was cut out from the thermoplastic resin film. R ₈₀ and R ₂₀ defined by the following formulas were determined from the reflectance in the wavelength band 400 to 750 nm measured by the method (2).
The wavelength exceeding the reflectivity of R _{80 in} the lowest wavelength band is defined as the low wavelength side λ ₈₀ , and the wavelength closest to λ ₈₀ exceeding the reflectivity of R ₂₀ from the low wavelength side λ ₈₀ to the low wavelength side is defined as the low wavelength side λ _20. , the low-wavelength-side lambda ₈₀ - and the wavelength band of the low-wavelength-side lambda ₂₀ and the low-wavelength-side λ ₈₀ -λ _20.
The wavelength exceeding the reflectance of R _{80 in} the highest wavelength band is defined as the high wavelength side λ ₈₀ , and the wavelength closest to λ ₈₀ exceeding the reflectance of R ₂₀ from the high wavelength side λ ₈₀ to the high wavelength side is defined as the high wavelength side λ _20. , high wavelength side lambda ₂₀ - and the wavelength band of the high wavelength side lambda ₈₀ and the high wavelength side λ ₂₀ -λ _80.
Formula (iii) R ₈₀ = {(maximum reflectance−minimum reflectance) × 0.8} + minimum reflectance (%)
Formula (iv) R ₂₀ = {(maximum reflectance−minimum reflectance) × 0.2} + minimum reflectance (%)
(4) Color tone (a ^* [12 °], b ^* [12 °]), (a ^* [30 °], b ^* [30 °])
From the spectral reflectance data obtained in (2), a spectral reflection curve obtained by averaging the P wave and S wave of the respective spectral reflection curves at the incident angles of 12 ° and 30 ° was obtained. Next, from the average spectral reflection curve at each angle, a ^* [12 °], b ^* [12 °], a ^* [30 °], b ^* [ 30 °] was calculated.

(5) Saturation C ^* [12 °]
The saturation C ^* [12 °] was determined from the following equation from the numerical values (a ^* [12 °], b ^* [12 °]) obtained in (4).
Formula (ii) C ^* [12 °] = √ (a ^* [12 °] ² + b ^* [12 °] ² )
(6) ΔC ^* (angle-dependent saturation difference) (incident angle 12 ° / 30 ° saturation difference)
From the numerical values of (a ^* [12 °], b ^* [12 °]) and (a ^* [30 °], b ^* [30 °]) obtained in (4), ΔC ^* (angle dependence) Saturation difference) (incident angle 12 ° / 30 ° saturation difference) was calculated.
Formula (i) √ {(a ^* [12 °] −a ^* [30 °]) ² + (b ^* [12 °] −b ^* [30 °]) ² }
(7) Haze It was performed using a turbidimeter NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd. at 23 ° C. and relative humidity 65%. The average value measured three times was taken as the haze value.

(8) Colorability at front view (5) Saturation C ^{* From} the measurement result of [12 °], the following criteria were used for evaluation.
A: C ^* [12 °] = 40 or more ○: C ^* [12 °] = 30 or more and less than 40 ×: C ^* [12 °] = less than 30

(9) Angular color change (6) From the measurement results of ΔC ^* (angle-dependent saturation difference), the following criteria were used for evaluation.
A: ΔC ^* (angle-dependent saturation difference) = 40 or more ○: ΔC ^* (angle-dependent saturation difference) = 30 or more and less than 40 Δ: ΔC ^* (angle-dependent saturation difference) = 25 or more and less than 30 ×: ΔC ^* (Angle-dependent saturation difference) = less than 25.

(10) High reflectivity (2) From the measurement result of 400-750 nm average reflectance, it evaluated on the following references | standards.
A: 400-750 nm average reflectance = 50% or more B: 400-750 nm average reflectance = 40% or more and less than 50% Δ: 400-750 nm average reflectance = 30% or more and less than 40% ×: 400-750 nm average reflectance = Less than 30%.

(11) Interlayer adhesion In accordance with JIS K5600-5-6-1999, a cross-cut spacing spacer (Cortech Co., Ltd .: model number CROSS CUT GUIDE 1.0) and a cutter knife were used, and the test specimen for evaluation was 6 in the vertical direction. Cut 6 times in the horizontal direction at intervals of 1 mm (this operation creates a grid of 5 × 5 = 25 squares). A transparent pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation: Model No. 31B) was pressure-bonded on the prepared grid, and the pressure-bonded tape was peeled off in a direction of about 60 ° to determine the number of peeled grids. The measurement was performed at N = 5, and the average value was evaluated according to the following criteria.
○: No peeling in all 25 grids (peeling number is 0 square or more and less than 1 square)
Δ: Lattice of 1 square or more and less than 2 squares in 25 squares peeled ×: Lattice of 2 squares or more in 25 squares peeled off.

(material)
(Resin A-1)
To a mixture of 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, 0.09 parts by weight of magnesium acetate and 0.03 parts by weight of antimony trioxide are added with respect to the amount of dimethyl terephthalate, and the temperature is raised by a conventional method. Then, a transesterification reaction is performed. Subsequently, 0.020 part by weight of 85% aqueous solution of phosphoric acid is added to the transesterification reaction product with respect to the amount of dimethyl terephthalate, and then transferred to a polycondensation reaction tank. Furthermore, the reaction system was gradually depressurized while being heated and heated, and a polycondensation reaction was conducted at 290 ° C. under a reduced pressure of 1 mmHg by a conventional method. Polyethylene terephthalate having an intrinsic viscosity (IV) of 0.61 (hereinafter referred to as PET) Got).

(Resin A-2)
Polymerization was carried out in the same manner as Resin A-1, except that a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol was used. , Sometimes referred to as PEN).

(Resin A-3)
The polycondensation reaction time was adjusted during polymerization of Resin A-1 to obtain polyethylene terephthalate (hereinafter sometimes referred to as PET) having an intrinsic viscosity (IV) of 0.66.

(Resin B-1)
A copolymerized polyethylene terephthalate obtained by mixing polyethylene terephthalate copolymerized with 21 mol% of spiroglycol (SPG) having an intrinsic viscosity (IV) of 0.60 and 24 mol% of cyclohexanedicarboxylic acid (CHDC) and resin A-3 at a ratio of 4: 1.
(Resin B-2)
Copolymerized polyethylene terephthalate in which polyethylene terephthalate copolymerized with 30 mol% of cyclohexanedimethanol (CHDM) having an intrinsic viscosity (IV) of 0.75 and resin A-3 are mixed at a ratio of 4: 1.
(Resin B-3)
Copolymerized polyethylene terephthalate obtained by mixing polyethylene terephthalate copolymerized with 30 mol% of cyclohexanedimethanol (CHDM) having an intrinsic viscosity (IV) of 0.75 and resin A-3 at 3: 2.

(Resin B-4)
A copolymerized polyethylene terephthalate obtained by mixing polyethylene terephthalate copolymerized with 21 mol% of spiroglycol (SPG) having an intrinsic viscosity (IV) of 0.55 and 24 mol% of cyclohexanedicarboxylic acid (CHDC) and resin A-3 at a ratio of 4: 1.

(Resin B-5)
Copolymerized polyethylene terephthalate in which polyethylene terephthalate copolymerized with 30 mol% of cyclohexanedimethanol (CHDM) having an intrinsic viscosity (IV) of 0.70 and resin A-3 are mixed at a ratio of 4: 1.

(Resin B-6)
Copolymerized polyethylene terephthalate obtained by mixing polyethylene terephthalate copolymerized with 30 mol% of cyclohexanedimethanol (CHDM) having an intrinsic viscosity (IV) of 0.75 and resin A-3 at a ratio of 2: 3.

(Composition of easy-adhesion layer-I)
-Aqueous dispersion of acrylic / urethane copolymer resin (a): Sannaron WG658 (solid content concentration 30% by weight), manufactured by Sannan Synthetic Chemical Co., Ltd.
-Aqueous dispersion of isocyanate compound (b): Elastron E-37 (solid content concentration: 28% by weight) manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
-Aqueous dispersion of epoxy compound (c): manufactured by DIC Corporation, CR-5L (solid content concentration: 100% by weight)
An aqueous dispersion of the composition (d) comprising a compound having a polythiophene structure and a compound having an anion structure (solid content concentration: 1.3% by weight)
-Aqueous dispersion of oxazoline compound (e): Nippon Shokubai Co., Ltd., Epocross WS-500 (solid content concentration 40% by weight)
-Aqueous dispersion of carbodiimide compound (f): Nisshinbo Co., Ltd., Carbodilite V-04 (solid content concentration 40%)
-Silica particles (g): JGC Catalysts & Chemicals, Spherica slurry 140 (solid content 40%)
-Acetylene diol-based surfactant (h): manufactured by Nissin Chemical Co., Ltd., Olfine EXP4051 (solid content concentration 50%)
-Aqueous solvent (i): pure water The above-mentioned (a) to (h) in terms of solid weight ratio (a) / (b) / (c) / (d) / (e) / (f) / ( g) / (h) = 100/100/75/25/60/60/10/15 and mixed so that the solid content concentration of the aqueous coating material is 3% by weight. Mix and adjust the concentration.

Example 1
Resin A-1 and Resin B-1 were melted at 280 ° C. and Resin B-1 at 270 ° C. with separate vented twin screw extruders, respectively, through a gear pump and a filter, They were merged in a 549-layer feed block having one member having 274 slits separately. The outermost layers on both sides to be the thick film layer are resin A-1, and the resin A-1 and the resin B-1 are alternately laminated, and the layers made of the adjacent resin A-1 and the resin B-1 are formed. The layer thickness was made to be substantially the same. Next, after being led to a T-die and molded into a sheet, it was brought into close contact with a casting drum maintained at a surface temperature of 25 ° C. by applying an electrostatic force and rapidly cooled and solidified to obtain a cast film.

  The obtained cast film was heated with a roll group set at 75 ° C., then stretched 3.3 times in the longitudinal direction while rapidly heating from both sides of the stretch section with a radiation heater between 100 mm in length, and then cooled once. Thus, a uniaxially stretched film was obtained. Subsequently, both surfaces of the uniaxially stretched film were subjected to corona discharge treatment in the air, the coating tension of the film was 55 mN / m, and composition-I of the easy adhesion layer was applied to both surfaces of the film with a # 4 metabar.

  The obtained uniaxially stretched film was guided to a tenter, and after preheating with 100 ° C hot air, it was stretched 3.5 times in the transverse direction at a temperature of 110 ° C. The stretched film is directly heat-treated with hot air at 240 ° C. in the tenter, then subjected to a relaxation treatment of 7% in the width direction at the same temperature, then cooled to room temperature and wound up with a winder. An axially stretched film was obtained. The total film thickness of the obtained biaxially stretched laminated film was 70 μm. The layer design of this laminated film is as shown in FIG. 1, and the layer thickness of each layer was controlled by adjusting the slit gap. A cross section in the thickness direction of the laminated film was observed with a TEM, and a layer thickness distribution was determined by image processing. The layer thicknesses of layer number 1 and layer number 549, which are the outermost layers, were both 6 μm, and the layer thickness of layer number 275 composed of resin A-1 was 4 μm. The properties and evaluation results of this thermoplastic resin film are shown in Table 1.

(Example 2)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the total film thickness was changed from 70 μm to 80 μm. The results are shown in Table 1.

(Example 3)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the total film thickness was changed from 70 μm to 60 μm. The results are shown in Table 1.

Example 4
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the resin B-1 was changed to the resin B-2. The results are shown in Table 1.

(Example 5)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the resin B-1 was changed to the resin B-3. The results are shown in Table 1.

(Example 6)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the resin A-1 was changed to the resin A-2. The results are shown in Table 1.

(Example 7)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the thickness of the layer was adjusted by changing the slit shape of the feed block so that the layer design of the film was as shown in FIG. The layer thicknesses of layer number 1 and layer number 549, which are the outermost layers, were both 6 μm, and the layer numbers of layer number 183 and layer number 366 composed of resin A-1 were 4 μm. The properties and evaluation results of this thermoplastic resin film are shown in Table 1.

(Example 8)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the thickness of the feed block was changed by changing the slit shape of the feed block so that the layer design of the film was as shown in FIG. The layer thicknesses of layer number 1 and layer number 349, which are the outermost layers, were both 6 μm, and the layer thickness of layer number 175 composed of resin A-1 was 4 μm. The properties and evaluation results of this thermoplastic resin film are shown in Table 1.

Example 9
A thermoplastic resin film was obtained in the same manner as in Example 8 except that the total film thickness was changed from 45 μm to 35 μm. The results are shown in Table 1.

(Example 10)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the thickness of the feed block was changed by changing the slit shape of the feed block so that the layer design of the film was as shown in FIG. The layer thicknesses of the layer number 1 and the layer number 249 that are the outermost layers were both 6 μm, and the layer thickness of the layer number 125 composed of the resin A-1 was 4 μm. The properties and evaluation results of this thermoplastic resin film are shown in Table 1.

(Comparative Example 1)
Resin A-1 was changed to Resin A-3, Resin B-1 was changed to Resin B-4, and Resin B-4 was changed to a molten state at 280 ° C. with a vented twin screw extruder. Thus, a thermoplastic resin film was obtained. The results are shown in Table 1.

(Comparative Example 2)
A thermoplastic resin film was obtained in the same manner as in Comparative Example 1 except that the total film thickness was changed from 70 μm to 80 μm. The results are shown in Table 1.

(Comparative Example 3)
A thermoplastic resin film was obtained in the same manner as in Comparative Example 1 except that the total film thickness was changed from 70 μm to 60 μm. The results are shown in Table 1.

(Comparative Example 4)
A thermoplastic resin film was obtained in the same manner as in Comparative Example 1 except that the resin B-1 was changed to the resin B-5. The results are shown in Table 1.

(Comparative Example 5)
A thermoplastic resin film was obtained in the same manner as in Example 1 except that the resin B-1 was changed to the resin B-6. The results are shown in Table 1.

(Comparative Example 6)
The thermoplastic resin film was obtained in the same manner as in Example 1 except that the thickness of the layer design of the film was changed by changing the slit shape of the feed block so that the thickness was 24 μm. The layer thicknesses of the layer number 1 and the layer number 149 which are the outermost layers were both 10 μm, and the layer thickness of the layer number 75 composed of the resin A-1 was 4 μm. The properties and evaluation results of this thermoplastic resin film are shown in Table 1.

  The thermoplastic resin film of the present invention highly reflects visible light, is highly colored when viewed from the front, and has a remarkable change in saturation with a slight change in angle. Therefore, it can use suitably for the anti-counterfeit sheet | seat, IC card decoration, decorations, such as a household appliance, the decoration film used for an art or a craft, etc. using the characteristic.

1: Layer number 2: Layer thickness 3: Thick film layer 4: Layer thickness distribution of layer A 5: Layer thickness distribution of layer B 6: Member plate 7: Resin introduction plate 8: Slit plate 8a: Slit 8b: Slit 9: Resin introduction plate 10: Slit plate 11: Resin introduction plate 12: Slit plate 13: Resin introduction plate 14: Slit plate 15: Resin introduction plate 16: Member plate 17: Feed block 18: Inlet 19: Liquid reservoir 20: Each Ridge line 21 at the top of the slit: upper end part 22 of the ridge line at the top of each slit: lower end part 23 of the ridge line at the top of each slit: resin introduced into the slit 24: resin outlet

Claims (8)

A color tone calculated using a calculation formula stipulated in JISZ8781 with an average reflectance of 30% or more in a wavelength band of 400 to 750 nm measured at an incident angle of 12 °, and a spectral reflectance measured at an incident angle of 12 ° and 30 °. Thermoplastic resin characterized by values (a ^* [12 °], b ^* [12 °]) and (a ^* [30 °], b ^* [30 °]) satisfying the following formula (i) the film.
Formula (i) √ {(a ^* [12 °] −a ^* [30 °]) ² + (b ^* [12 °] −b ^* [30 °]) ² } ≧ 25 The thermoplastic resin film according to claim 1, wherein the color tone (a ^* [12 °], b ^* [12 °]) satisfies the following formula (ii).
Formula (ii) √ (a ^* [12 °] ² + b ^* [12 °] ² ) ≧ 30 A layer having a thermoplastic resin A as a main component (A layer) and a layer having a thermoplastic resin B as a main component (B layer), wherein the A layer and the B layer are adjacent to each other; The total number of B layers is 200 layers or more, The thermoplastic resin film of Claim 1 or 2 characterized by the above-mentioned. The thermoplastic resin film according to any one of claims 1 to 3, wherein delamination does not occur in an adhesion test by a cross-cut method according to JISK5600. The thermoplastic resin film according to claim 4, wherein the thermoplastic resin A is a crystalline thermoplastic resin, and the thermoplastic resin B is an amorphous thermoplastic resin. The crystalline thermoplastic resin is crystalline polyethylene terephthalate, and the amorphous thermoplastic resin is spiroglycol copolymerized polyethylene terephthalate and / or cyclohexanedimethanol copolymerized polyethylene terephthalate, Item 6. The thermoplastic resin film according to Item 5. The thermoplastic resin film according to claim 1, which is used for a forgery prevention sheet. The forgery prevention sheet using the thermoplastic resin film in any one of Claims 1-7.

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