JP2013129077A - Laminated polyester film for in-mold transfer foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyester film for in-mold transfer foil which can apply more superior matte appearance than that of a conventional film to a molded product surface, reduces unevenness of the matte appearance and has resistance to scraping during handling.SOLUTION: A laminated polyester film includes: a base material layer comprising polyester having ≥245°C of a melting point; and a matte layer located on one face of the base material layer and comprising polyester having 220-235°C of a melting point. The matte layer includes, on the basis of the weight thereof, ≥15 wt.% and ≤33 wt.% of particles. A relationship between thickness (t) of the matte layer and an average particle size (r) of the matte layer is in a range of 1.0≤r-t≤4.0 (μm), and film surface glossiness (G) on a matte face side is ≥5 and ≤25. A void generation rate of the film is ≤1.0%.

Description

  The present invention relates to a laminated polyester film for in-mold transfer foil. More specifically, the present invention relates to a laminated polyester film for in-mold transfer foil that is useful as a support film for a transfer foil for in-mold molding and transfer that is transferred and printed simultaneously with molding in injection molding or the like.

Conventionally, as a transfer foil for in-mold molding transfer (hereinafter sometimes referred to as in-mold molding transfer foil), a polyester film such as a polyethylene terephthalate film is used as a base film, and a release layer (hereinafter, referred to as a release film) A laminated film in which a printing layer is coated thereon is used.
This in-mold molding transfer foil is transferred to a molded product using an in-mold molding method, and then peeled and separated between the release layer surface and the printing layer surface. That is, after molding transfer, the printed layer is adhered to the surface of the molded product and taken out as a product, and the release layer is removed after molding in a state of being laminated on the base film.

Conventionally, a flat base film has been used for in-mold molding transfer foil to obtain a clear molded product appearance, but in recent years, the surface appearance of molded products with a matte appearance has also been applied using the in-mold transfer method. Attempts to do so are being made. Accordingly, there has been a demand for a base film that has excellent matte appearance transferability and has moldability with respect to the transfer foil base film.
As such a base film, for example, Patent Document 1 discloses a composite film in which two or more layers are laminated by a coextrusion method, and the glossiness Gs (60 °) on one side of the film is 10 to 45%. A film has been proposed. However, the gloss of the specifically described laminated polyester film is 28-30, and the matting effect is insufficient. Further, in order to improve the matting effect, it is necessary to increase the particle content of the matting layer. However, according to our study, simply increasing the particle content does not reduce the surface gloss (matte effect) of the in-mold transfer molded product, even if the gloss of the film can be reduced. Also, glossy spots were likely to occur.

Patent Document 2 proposes a biaxially stretched coextruded laminated polyester film having a matte property. However, even when this film is used as a support film for an in-mold molding transfer foil, the amount of particles added to the layer for obtaining a matting effect is 1 to 10% by weight, so that it has a good matte appearance. An in-mold transfer molded product was not obtained.
Patent Document 3 proposes a laminated polyester film for molding simultaneous transfer containing 0.3 to 20% by weight of particles having an average particle diameter of 1.0 to 20 μm in a matte layer. However, the particle content of the laminated polyester film specifically described is as small as 3.3% by weight, and an in-mold transfer molded product having a good matte appearance cannot be obtained. Further, just by increasing the particle content in order to improve the matting effect, the matting effect of the obtained in-mold transfer molded product can be improved even if the matting effect of the film itself can be improved as in the above-mentioned Patent Document 1. Insufficient glossy spots are also likely to occur.

Japanese Patent Laid-Open No. 04-110147 JP 2002-200723 A JP 2010-201858 A

  The object of the present invention is to provide a laminated polyester for in-mold transfer foil that can give a matte appearance on the surface of a molded product that is even better than before, has few spots on the matte appearance, and is excellent in abrasion resistance during handling. To provide a film.

  As a result of intensive studies to solve the above problems, the present inventors have increased the particle content to increase the matting effect of the film, but the matting effect of the obtained in-mold transfer molded product is insufficient, The reason that glossy spots are likely to occur is that the surface protrusions of the film are crushed by the resin pressure during in-mold molding. Specifically, the amount of voids between the matte layer particles and the matrix polymer is small. As a result of investigating that the void is crushed by the resin pressure at the time of in-mold molding and further studying it, the present invention has been completed.

That is, the object of the present invention is “a laminated polyester film having a base material layer made of polyester having a melting point of 245 ° C. or more and a matte layer made of polyester having a melting point of 220 to 235 ° C. on one side, The mat layer contains particles in the range of 15 wt% to 33 wt% based on the weight of the layer, and the relationship between the thickness (t) of the mat layer and the average particle diameter (r) of the mat layer is 1. 0.0 ≦ r−t ≦ 4.0 (μm), the film surface glossiness (G ₆₀ ) on the matte surface side is 5 or more and 25 or less, and the void generation rate of the film is 1.0% or less. This is achieved by a “laminated polyester film for in-mold transfer foil”.
In the laminated polyester film for in-mold transfer foil of the present invention, as a preferred embodiment, the maximum particle size of the particles contained in the matte layer is 16 μm or less, and the particles contained in the matte layer are made of synthetic zeolite. What has at least any one of these is also included.

  By using the laminated polyester film for in-mold transfer foil of the present invention, it is possible to produce a molded product that exhibits an excellent matte appearance and small spots of the matte appearance. Moreover, since it is excellent in abrasion resistance during handling, its industrial value is extremely large.

The present invention will be described in detail below.
<Polyester film>
The laminated polyester film for transfer foil of the present invention is a laminated polyester film having a base material layer made of polyester and a matte layer made of polyester on one side.

(Base material layer)
The polyester constituting the base material layer of the laminated polyester film for in-mold transfer foil needs to have a melting point of 245 ° C. or higher, preferably in the range of 250 to 270 ° C. By supporting, an excellent matte appearance can be imparted to the in-mold transfer molded product while maintaining a sufficient in-mold moldability, and a small matte appearance spot can be obtained.

  The polyester constituting the base material layer used in the present invention is a linear saturated polyester composed of an aromatic dibasic acid component and a diol component, and specifically, polyethylene terephthalate, poly (1,4-cyclohexene). Silylene methylene terephthalate), polyethylene-2,6-naphthalate, and polyesters in which the third component is copolymerized therewith, and polyesters having a melting point of 245 ° C. or higher are exemplified. Of these, polyethylene terephthalate, polyethylene-2,6-naphthalate, and those obtained by copolymerizing a third component are preferable because of a good balance between mechanical properties and optical properties, and homopolyesters are particularly preferable. When the melting point of the polyester of the base material layer is less than 245 ° C., the film tends to break during high-temperature heat treatment for reducing voids described later.

  When the polyester is copolymerized polyethylene terephthalate, isophthalic acid is most preferable as the copolymer component, but as other copolymer components, aromatic dicarboxylic acids such as phthalic acid and 2,6-naphthalenedicarboxylic acid, adipic acid, Examples include aliphatic dicarboxylic acids such as azelaic acid, sebacic acid and 1,10-decanedicarboxylic acid, and aliphatic diols such as 1,4-butanediol, 1,6-hexanediol and neopentyl glycol. And alicyclic diols such as 1,4-cyclohexanedimethanol. These can be used alone or in combination of two or more.

  The intrinsic viscosity (η) of the polyester is preferably in the range of 0.50 to 0.70 dl / g (measured with an o-chlorophenol solution at 35 ° C.). The lower limit of the intrinsic viscosity is preferably 0.55 dl / g. The upper limit is preferably 0.65 dl / g, more preferably 0.60 dl / g. When the intrinsic viscosity is less than the lower limit, the tear is likely to occur during in-mold molding. On the other hand, when exceeding an upper limit, melt viscosity becomes high too much, the load in a film forming process increases, and productivity falls.

The base material layer does not contain particles, or the content of the particles is more than 0% by weight and 2.9% by weight or less based on the weight of the base material layer. When the particles are included, the concentration of the particles in the base material layer is more preferably 2.5% by weight or less, and further preferably 2.0% by weight or less.
When the content of particles in the base material layer exceeds the upper limit value, in-mold moldability and surface resistance characteristics of the antistatic layer may be deteriorated.

The kind of particle | grains used for a base material layer will not be specifically limited if it is a particle normally added to a film, Any of an inorganic particle and an organic particle may be sufficient. Specifically, amorphous silica (colloidal silica), silica, talc, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, alumina, carbon black, titanium dioxide, kaolin Synthetic zeolite, crosslinked polystyrene particles, crosslinked acrylate particles, and the like. One kind of these particles, or two or more kinds of different particles may be contained, or a mixture of particles of the same kind and different particle sizes may be used.
For the base material layer, other resins than the polyester, colorant, antistatic agent, stabilizer, antioxidant, ultraviolet absorber, fluorescent whitening agent, etc. are required as long as the object of the present invention is not impaired. It can be contained accordingly.

(Matte layer)
The polyester constituting the mat layer of the present invention reduces the void generation rate to 1.0% or less while maintaining the film properties described later. Since heat treatment is performed at a temperature of the melting point of polyester + 10 ° C. or higher, the melting point needs to be 235 ° C. or lower. On the other hand, if the melting point is too low, the matte layer tends to flow during in-mold molding and light spots are likely to occur, so it is necessary that the temperature be 220 ° C. or higher. A particularly preferable melting point range is 225 to 230 ° C.
Examples of the polyester constituting the mat layer include copolymer polyethylene terephthalate having a melting point of 220 to 235 ° C., copolymer poly (1,4-cyclohexylenedimethylene terephthalate), and copolymer polyethylene-2,6-naphthalate. It is possible. Among these, copolymerized polyethylene terephthalate and copolymerized polyethylene-2,6-naphthalate are preferable, and it is preferable to use a polyester of the same system as the base material layer (polyester having the same main repeating unit).

In addition, the melting point of the polyester used for the matte layer does not need to be low from the stage before forming the film, and may be low after the stretching treatment. For example, homopolyethylene terephthalate and other polyesters may be prepared, and these may be melt-kneaded and transesterified during film formation to bring the melting point to the above range.
The intrinsic viscosity (η) of the polyester is preferably in the range of 0.50 to 0.70 dl / g (measured with an o-chlorophenol solution at 35 ° C.). The lower limit of the intrinsic viscosity is preferably 0.55 dl / g. The upper limit is preferably 0.65 dl / g, more preferably 0.60 dl / g. When the intrinsic viscosity is less than the lower limit, the tear is likely to occur during in-mold molding. On the other hand, when exceeding an upper limit, melt viscosity becomes high too much, the load in a film forming process increases, and productivity falls.

  In the mat layer of the present invention, it is necessary to contain particles in the range of 15 wt% to 33 wt% based on the weight of the mat layer, and preferably 20 wt% to 30 wt%. When the content of the particles is less than the lower limit value, the glossiness described later cannot be achieved, and a sufficient matte appearance cannot be imparted to the surface of the molded product. On the other hand, when the content of the particles exceeds the upper limit value, the film-forming property is lowered and the film is easily broken, and the film formation itself becomes difficult.

  The average particle diameter of the particles is preferably 2.5 μm or more and 5.5 μm or less. When the average particle diameter of the particles is less than the lower limit, the effect of lowering the glossiness is lowered, and if the amount of particles added is further increased to lower the glossiness, sufficient moldability may not be obtained. If the average particle size of the particles exceeds the upper limit, printing omission may occur on the surface of the molded product.

Further, the relationship between the thickness (t) of the matte layer and the average particle diameter (r) of the matte layer needs to satisfy 1.0 ≦ rt−4.0 (μm). When rt is less than 1.0 μm, the particles are buried in the matte layer and the matting effect becomes insufficient, and the glossiness described later increases. On the other hand, when rt exceeds 4.0 μm, the particles are likely to be scraped because they come out of the surface of the matte layer, and the irregularities are so severe that problems such as printing omission may occur.
The maximum particle size of the particles is preferably 16 μm or less, more preferably 15 μm or less, and still more preferably 12 μm or less. Here, the maximum particle size is represented by the particle size (d ₉₈ ) at 98% of the cumulative particle size distribution curve. When the maximum particle diameter of the particles in the matte layer satisfies the above, printing omission can be suppressed.

  In the present invention, the type of particles is not particularly limited, and may be either inorganic particles or organic particles, amorphous silica (colloidal silica), silica, talc, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate. Examples thereof include lithium phosphate, calcium phosphate, magnesium phosphate, alumina, carbon black, titanium dioxide, kaolin, synthetic zeolite, crosslinked polystyrene particles, and crosslinked acrylate particles. Among these particles, at least one of amorphous silica and synthetic zeolite is more preferable, and any one of them may be used or used in combination. Moreover, you may use the mixture of the particle | grains from which the particle size differs in the same kind.

In addition, in the case of amorphous silica, a surface treated with a silane coupling agent is preferable in order to reduce moisture adsorption.
Particularly preferred particles are synthetic zeolite, and in order to reduce the adsorptivity of the synthetic zeolite, in particular the moisture adsorptivity, those having an acid treatment to such an extent that the particle shape is not destroyed with an acid having a pH of 5 or more are preferred. What was heat-processed at the above temperature is preferable.

The shape of the particle is not particularly defined, but if it is indefinite, the particle size distribution is widened, and coarse protrusions due to aggregation are likely to occur, and printing omission may occur. Therefore, the shape of the particles is preferably spherical or multifaceted. Examples of preferable particles include spherical or multi-faceted synthetic zeolite. In the case of multi-faceted particles, a matte effect is easily obtained. Among the polyhedral particles, cubic particles are particularly preferable.
The method of adding these particles is not particularly limited, and examples thereof include a method of adding to a glycol dispersion during polycondensation of polyester, or a method of adding to a matte layer via a master batch during extrusion.

  The particles contained in the matte layer have a weight loss rate of 0% or more and 3% or less at 300 ° C. when the temperature is increased from 30 ° C. to 500 ° C. at a temperature increase rate of 10 ° C./min. It is preferable that it is 1.5% or more and 2.0% or less. If the weight reduction rate exceeds the upper limit, it may cause foaming in the polyester film production process or molding process or reduce the molecular weight of the polyester to reduce the film formability and processability of the film, In particular, when a large amount of particles are contained, the film forming property and workability of the film may be significantly reduced.

In addition to the above, the matte layer of the present invention needs to have a surface glossiness (G ₆₀ ) of 5 or more and 25 or less. The surface glossiness (hereinbelow, simply referred to as glossiness) here is defined by values measured at 60 ° for both the incident angle and the light receiving angle in accordance with JIS standard Z8741. When the laminated polyester film of the present invention has a matte layer having the glossiness, when used as a support film for a transfer foil for in-mold molding transfer, the matte surface appearance having a low glossiness is imparted to the surface of the molded product. Can do. In addition, when the easily bonding layer mentioned later is provided in the matte layer surface, surface glossiness is the value measured in the state with an easily bonding layer.

The lower limit of the glossiness is preferably 8. Further, the upper limit of the glossiness is preferably 20, and more preferably 18. When such glossiness is less than the lower limit, not only in-mold moldability becomes insufficient due to excessive inclusion of particles, but it is also technically difficult to reduce the glossiness to below the lower limit. . On the other hand, when the glossiness exceeds the upper limit, it becomes difficult to impart an excellent matte surface appearance with low glossiness to the surface of the molded product.
In order to obtain such surface glossiness, as described above, the particle content in the mat layer and the relationship between the average particle diameter and the mat layer thickness may be adjusted.

In the matte layer of the present invention, the 10-point average roughness Rz of the surface is preferably 5000 nm or more and 8000 nm or less, and particularly preferably 5500 nm or more and 6500 nm or less. When the 10-point average roughness Rz on the surface of the matte layer is within such a range, it is possible to eliminate printing omission while improving the matte appearance of the molded product after transfer. When the 10-point average roughness Rz on the surface of the matte layer is less than the lower limit value, it may not be possible to impart a sufficient matte appearance to the surface of the molded product. Further, when the 10-point average roughness Rz on the surface of the matte layer exceeds the upper limit value, although the matte appearance is good, the surface irregularities are too severe, so that a problem such as printing omission may occur. is there.
The 10-point average roughness Rz on the surface of the matte layer is achieved by adjusting the average particle size of the particles in the matte layer and the maximum particle size.

(Void occurrence rate)
It is essential that the laminated polyester film for in-mold transfer foil of the present invention has a void generation rate of 1.0% or less, preferably 0.5% or less, more preferably 0.3% or less. In addition, a void generation rate is the value calculated | required by following formula (2).
_{d = d T × Wα × t} / T / 100 + 1.4 (100-Wα × t / T) / 100 (1)
(Where d is the true density, d _T is the particle density (g / cm ³ ), Wα is the particle content (% by weight), t is the mat layer thickness (μm), and T is the film thickness (μm). 1.4 represents the polyester density)
Void generation rate (%) = (d−d ₀ ) / d × 100 (2)
(In the above formula, d represents the true density and d ₀ represents the apparent density.)

  A laminated polyester film having a matte layer containing a large amount of particles in order to lower the glossiness is presumed to be because voids are likely to be formed around the particles. In conventional films with a void generation rate of 1.0% or more, The void is crushed by the resin pressure at the time of in-mold transfer molding, and the surface of the portion is flattened to generate gloss spots. In contrast, the film of the present invention, as described later, uses polyester having a specific melting point for the base layer and matte layer, and adjusts the heat setting temperature during film formation to crush voids formed on the particle surface. Since the void generation rate is adjusted to 1.0% or less, partial flattening of the film surface due to resin pressure during molding can be suppressed while maintaining moldability during in-mold transfer molding. . As a result, it is possible to obtain a molded product that exhibits an excellent matt appearance and also has a small matt appearance.

(Total film thickness)
The laminated polyester film of this invention should just have the thickness used as a support film for in-mold transfer foil, Preferably it is 10-150 micrometers, Most preferably, it is 20-100 micrometers.

(Antistatic layer)
The laminated polyester film for in-mold transfer foil of the present invention may further have an antistatic layer on the side opposite to the surface on which the matte layer of the base material layer is laminated, and the surface resistance of the antistatic layer is 1 ×. It is preferably 10 ¹³ Ω / □ or less. By having such an antistatic layer, sticking of the transfer foils due to charging and adhesion of dust and dirt to the transfer foil surface during handling of the in-mold transfer foil are suppressed. In such an antistatic layer, it is preferable to use a cationic polymer as an antistatic agent, and it is preferable to use a silicone or wax having a reactive group as a releasing component in combination. In the antistatic layer, various crosslinking agents may be used in order to further improve the cohesive strength of the coating film, and other surfactants may be used in order to improve the coating property of the coating film.

(Easily adhesive layer)
The laminated polyester film for in-mold transfer foil of the present invention can further have an easy-adhesion layer on the matte surface side for the purpose of enhancing the adhesion to the release layer (medium layer). The easy adhesion layer is preferably an easy adhesion coating layer provided by coating. For the easy adhesion layer, it is preferable to use a copolymerized polyester in order to obtain high adhesion to a release layer provided when used as an in-mold transfer foil. A cross-linking agent, particles, a surfactant and the like may be further used for the easy adhesion layer.

(Film production method)
The laminated polyester film for in-mold transfer foil of the present invention can be produced, for example, by the following method. That is, the matte layer and the base material layer are laminated and extruded by a co-extrusion method, cooled and solidified with a casting drum to form an amorphous unstretched film, and then the machine direction (hereinafter, machine axis direction, continuous film forming direction, longitudinal direction or MD direction). And the transverse direction (hereinafter, sometimes referred to as the width direction and the TD direction).

  Stretching in the machine direction is, for example, drawn at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., in the machine direction of 2.0 to 4.0 times, preferably 2.5 to 3.5 times. Stretching in the transverse direction is, for example, stretched at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., 2.0 to 4.0 times, preferably 3.0 to 4.0 times. In addition, it is preferable that the area magnification after biaxial stretching is 13 or less. Moreover, although the method of extending | stretching of one direction can also be used by the multistage of 2 steps | paragraphs or more, it is preferable that the final draw ratio exists in the above-mentioned range.

  After stretching the film, it is necessary to perform heat setting treatment. The heat setting temperature is set to a temperature range of 10 ° C. or more higher than the polyester melting point of the matte layer and not more than the polyester melting point of the base layer, and the void generation rate is It is preferable to adjust appropriately within the time of 1 to 30 seconds so that it may become 1.0% or less. At that time, it may be performed under a limited contraction or expansion within 20%, or under a constant length, or may be performed in two or more stages.

When the antistatic layer is provided, it is provided by applying a coating agent containing an antistatic layer forming component on the surface of the base material layer opposite to the matte layer. As the film at the time of application, a polyester film before completion of crystal orientation is preferable. In this case, it is preferable to perform a stretching process for completing the crystal orientation on the film after the coating, and further a heat setting process.
Moreover, when providing an easily bonding layer, it provides by apply | coating the coating agent containing an easily bonding layer forming component on the matte layer of a polyester film. In this case, it is preferable to provide an easy adhesion layer simultaneously with the antistatic layer.

(In-mold transfer foil)
The laminated polyester film of the present invention is used for in-mold transfer applications, has a higher matte property than conventional ones, and can impart a matte appearance with smaller spots to the surface of the molded product, and is sufficient for in-mold transfer foil It also has sex.
If the laminated polyester film for in-mold transfer foil of the present invention is provided with an easy-adhesion layer on the matte surface side, it should be used in a mode in which a release layer (medium layer) and a printing layer are further formed on the easy-adhesion layer. The printed layer is transferred and adhered to the surface of the molded product and taken out as a product, and the other parts are used in a form that is removed from the product.

  Hereinafter, the present invention will be further described with reference to examples. In addition, the characteristic in an example was calculated | required with the following method.

1. Gloss _{(G 60)}
Based on JIS standard (Z8741), it measured using the gloss meter "VGS-SENSOR" by Nippon Denshoku Industries Co., Ltd. The incident angle and the light receiving angle were measured in increments of N = 5 at 60 °, and the average value was used. Further, the matte property was judged according to the following criteria.
◎: 5 or more and 18 or less ・ ・ ・ Excellent mattness ○: More than 18 and 25 or less ・ ・ ・ Good mattness ×: More than 25 ・ ・ ・ Poor mattness

2. Average particle diameter, maximum particle diameter (d ₉₈ )
The particles were stirred with a mixer so as to have a concentration of 3% in ethylene glycol, and measured using a laser scattering particle size distribution analyzer SALD-7000 manufactured by Shimadzu Corporation. The 50% volume particle size (D50) was determined from the particle size distribution measurement result, and this was used as the average particle size.
The maximum particle size was a median particle diameter d _98. Note the value of d ₉₈ is the particle diameter at 98% cumulative particle size distribution curve.

3. Particle content Cut out the matte layer from the film, select a solvent that dissolves the polyester resin and does not dissolve the particles, dissolves the sample, and then centrifuges the particles from the polyester resin to give a ratio to the total weight of the particles (weight %) Is the particle content.

4). Melting point
By using TA Instruments Q100 DSC, a method for obtaining a melting peak at a heating rate of 20 ° C./min. Samples are taken from each layer, and the amount is about 20 mg.

5. Each layer thickness of the film A sample was cut into a triangle, fixed in an embedded capsule, and then embedded in an epoxy resin. Then, after embedding the sample with a microtome (ULTRACUT-S) into a thin film section having a thickness of 50 nm in parallel with the microtome, the specimen was observed and photographed with a transmission electron microscope at an acceleration voltage of 100 kv. The thickness of each layer was measured at 10 points, and the average thickness was determined for each layer. As for the thickness of the matte layer, the thickness of the portion where no particles exist was measured.

6). Abrasion resistance Using a film sample cut to a width of 20 mm, the matte surface side of the film was applied to a cylindrical stainless steel fixing bar having a diameter of 10 mm, and a load of 200 g was applied for 80 m. The powder is observed and the abrasion resistance is evaluated as follows.
○: No sticking of powder to the bar (good wear resistance)
×: White powder adheres to the bar (poor abrasion resistance)

7). Printability A methyl ethyl ketone / toluene solution of melamine resin was applied on the surface opposite to the antistatic layer of the film to form a release layer film having a thickness of 1 μm. Here, for the adjustment of the thickness of 1 μm, the solution concentration is adjusted to be 1 μm in thickness on a smooth polyethylene terephthalate film not containing particles, and after checking the thickness, it is applied to the matte layer side under the same conditions. Went in the way.
Further, an ultraviolet curable hard coat layer (thickness: 5 μm) mainly composed of urethane acrylate was printed on the entire surface by a gravure printing method, and further a pattern layer was printed on the entire surface with an acrylic resin ink by a gravure printing method. The results were evaluated according to the following criteria.
○: Print appearance is good ×: Pattern layer is unclear (missing etc.)

8). Appearance of molded product (spot occurrence)
An in-mold transfer foil was placed on the mold so that the pattern layer (ink) side was the injection side, and a tray-like molded product having a size of 10 cm square, a rising edge of 15 mm, and a corner portion R of 2 mm was injection molded. At this time, polycarbonate / ABS resin alloy was used as the molding resin, and the resin temperature was 260 ° C., the mold temperature was 50 ° C., and the resin pressure was about 350 MPa. From the tray-shaped molded product, the transfer foil was peeled off at the interface between the release layer and the pattern layer to obtain a decorated molded part. The appearance of the molded part was evaluated by the following indicators. Appearance spots occur particularly at the injection site of the molded resin.
○: Spots are not visible on molded parts (appearance is good)
×: There are gloss spots on the molded parts (defective appearance)

9. Void generation rate The void generation rate was calculated | required from following formula (2) about the obtained film sample.
_{d = d T × Wα × t} / T / 100 + 1.4 (100-Wα × t / T) / 100 (1)
(Where d is the true density, d _T is the particle density (g / cm ³ ), Wα is the particle content (% by weight), t is the mat layer thickness (μm), and T is the film thickness (μm). 1.4 represents the polyester density)
Void generation rate (%) = (d−d ₀ ) / d × 100 (2)
(In the above formula, d represents the true density and d ₀ represents the apparent density.)

[Examples 1 to 15 and Comparative Examples 1 to 11]
The base material layer side is made of polyethylene terephthalate with no particles added (inherent viscosity 0.63 dl / g), and the matte layer side is made by adding particles to the copolymerized polyester shown in Table 1 and heated to 280 ° C., respectively. Supplied to an extruder, and the base layer polymer (A) and matte layer polymer (B) are merged using a two-layer feed block device in which the A / B laminate type is used, and the laminated state is maintained. As is, the sheet was melt-extruded from a die onto a rotary cooling drum maintained at 20 ° C. to form an unstretched film, and the unstretched film was stretched 3.4 times in the longitudinal direction. (Easily adhesive layer: 4% by weight, antistatic layer 3% by weight, each coating thickness (Wet) 4-5 μm) were each uniformly applied by a roll coater. The coated film was subsequently dried at 105 ° C., stretched 3.5 times in the transverse direction at 140 ° C., and further subjected to heat setting treatment at the temperature shown in Table 1 for 5 seconds to obtain a biaxially stretched laminated polyester film (thickness). 50 μm) was obtained. The evaluation results for each film are shown in Table 1.

As can be seen from Table 1, each of the films of Examples 1 to 15 according to the present invention can impart an excellent matte appearance to the molded product, and also has very few spots of the matte appearance in the molded product. there were.
On the other hand, the films of Comparative Examples 1, 3, and 4 did not have sufficient matting properties and could not give a sufficient matte appearance to the molded product. In the film of Comparative Example 2, since the particle concentration of the matte layer was too high, it was difficult to form a film due to tearing during film formation.
Although the film of Comparative Example 5 had good matting properties, the particle size was too large with respect to the thickness of the matting layer, so that the abrasion resistance was not sufficient.
The films of Comparative Examples 6 and 7 had good matting properties, but the heat setting temperature was too low, so the void generation rate could not be reduced to 1.0% or less, and the resulting molded product had a matte appearance. The spots were noticeable.
The films of Comparative Examples 8 and 9 had good matting properties, but the heat setting temperature could not be sufficiently increased because the melting point of the matting layer was too high. The molded product has a noticeable matte appearance.
The film of Comparative Example 10 had good matting properties, but the melting point of the matting layer was too low, so that the polymer of the matting layer flowed during molding, and the resulting molded product had noticeable matte appearance spots. It was.
Since the film of Comparative Example 11 had a polymer melting point of the base material layer that was too low, it was difficult to form a film due to tearing during film formation.

Abbreviations of polyesters in Table 1 are as follows.
PET: Polyethylene terephthalate IAx-PET: Isophthalic acid x mol% copolymerized polyethylene terephthalate NDCx-PET: 2,6-naphthalenedicarboxylic acid x mol% copolymerized polyethylene terephthalate

The components used in Table 2 are as follows: Copolyester: Acid component 50 mol% terephthalic acid / 45 mol% isophthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, glycol component 90 mol% ethylene glycol / It is comprised with 10 mol% of diethylene glycol (Tg = 40 degreeC). The polyester was produced as follows. That is, 30 parts of dimethyl terephthalate, 27 parts of dimethyl isophthalate, 5 parts of dimethyl 5-sodiumsulfoisophthalate, 36 parts of ethylene glycol and 3 parts of diethylene glycol were charged into the reactor, and 0.05 part of tetrabutoxy titanium was added thereto. Then, the temperature was controlled at 230 ° C. in a nitrogen atmosphere, and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C., and the inside of the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a copolyester. In addition, the manufacturing method of this copolyester is based on the method of Example 1 of Unexamined-Japanese-Patent No. 06-116487.

（上式（１）中、Ｒ^１、Ｒ^２はそれぞれＨであり、Ｒ^３は炭素数が３のアルキレン基であり、Ｒ^４、Ｒ^５はそれぞれ炭素数が１の飽和炭化水素基であり、Ｒ^６は炭素数が３のヒドロキシアルキレン基であり、Ｙ⁻はメチルスルホネートイオンである。） Cationic polymer: a copolymer having a structure represented by the following formula (1) consisting of 80 mol% / methyl acrylate 15 mol% / N-methylolacrylamide 5 mol%.

(In the above formula (1), R ¹ and R ² are each H, R ³ is an alkylene group having 3 carbon atoms, and R ⁴ and R ⁵ are each a saturated hydrocarbon group having 1 carbon atom. R ⁶ is a hydroxyalkylene group having 3 carbon atoms, and Y ⁻ is a methyl sulfonate ion.)

-Release agent 1: Amino group-containing silicone (trade name TSF4700, manufactured by GE Toshiba Silicones Co., Ltd.)
-Mold release agent 2: Polyethylene wax (trade name Pororin L-618, manufactured by Chukyo Yushi Co., Ltd.)
・ Crosslinking agent: Oxazoline compound (product name Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd.)
Surfactant: Polyoxyethylene (n = 7) lauryl ether (trade name NAROACTY N-70, manufactured by Sanyo Chemical Co., Ltd.)

The laminated polyester film of the present invention exhibits an excellent matte appearance and has a low void generation rate. Therefore, when used for an in-mold transfer foil, the laminated polyester film has a matte appearance superior to the conventional one and a molded product with less unevenness. It can be manufactured and has sufficient moldability for in-mold transfer foil.
Furthermore, when an easy-adhesion layer is provided on the matte surface side, it can be used in a form in which a release layer (medium layer) and a print layer are formed on the easy-adhesion layer. In other words, the printed layer is placed in the mold so that it comes into contact with the surface of the molded product, and after in-mold molding, the printed layer is transferred and bonded to the molded product surface and taken out as a product, and other parts are removed from the product. Is done.

Claims (3)

A laminated polyester film having a base material layer made of polyester having a melting point of 245 ° C. or higher and a matte layer made of polyester having a melting point of 220 to 235 ° C. on one side, the matte layer having a weight of the layer As a reference, particles are contained in the range of 15 wt% to 33 wt%, and the relationship between the thickness (t) of the matte layer and the average particle diameter (r) of the matte layer is 1.0 ≦ rt−4. In-mold transfer, characterized in that it is in the range of 0 (μm), the film surface glossiness (G ₆₀ ) on the matte side is 5 or more and 25 or less, and the void generation rate of the film is 1.0% or less Laminated polyester film for foil.   The laminated polyester film for in-mold transfer foil according to claim 1, wherein the maximum particle size of the particles contained in the matte layer is 16 µm or less.   The laminated polyester film for in-mold transfer foil according to claim 1 or 2, wherein the particles contained in the matte layer are made of synthetic zeolite.