JP2007045895A - Colored polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colored polyester film having high glossiness, satisfying a prescribed color tone, and having high design. <P>SOLUTION: The colored polyester film has 70-200 glossiness at least on one surface, and satisfies the expression (A): 100≥¾a*¾+¾b*¾≥5 (wherein, a* value and b* value are measured based on JIS-Z-8722). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a colored polyester film. Specifically, it is a colored polyester film having high glossiness and satisfying a predetermined color tone.

  Polyester films are used in a wide range of fields such as industrial materials, magnetic recording materials, optical materials, information materials, and packaging materials because of their excellent mechanical strength, thermal characteristics, humidity characteristics, and many other excellent characteristics.

In recent years, polyester films have been widely used as containers or the like by taking advantage of their excellent characteristics and forming them after being bonded to a base material, or forming polyester films themselves. At that time, in order to impart design properties, a polyester film exhibiting a high glossiness has been proposed (for example, Patent Document 1). However, since it is a white polyester film, the application to be used is limited, and it has been impossible to impart designability in various applications. Moreover, the polyester film excellent in the beauty is prescribed | regulated by prescribing | regulating a value and b value (for example, patent document 2). However, the glossiness is not described at all, and by using it as a bonding material on the outer surface side of a metal can or a metal can lid, an excellent beauty can be expressed, but the design property of the film itself Was inferior.
JP 2004-255636 A JP 2001-301025 A

  The object of the present invention is to solve the above-mentioned problems, high glossiness and satisfying a predetermined color tone, so that it has excellent design properties and high glossiness. It is providing the colored polyester film which can be used for a use.

In order to solve the above problems, the colored polyester film of the present invention is
(1) A colored polyester film having a gloss value of 70 to 200 on at least one side of the film, and a ^* value and b ^* value based on JIS Z-8722 satisfying the following formula (A):
100 ≧ | a ^* | + | b ^* | ≧ 5 (A)
(2) The colored polyester film according to claim 1, wherein a ^* value and b ^* value based on JIS-Z-8722 satisfy the following formula (B):
50 ≧ | a ^* | + | b ^* | ≧ 15 (B)
(3) The coloring according to (1) or (2), wherein a ^* value, b ^* value, and L ^* value based on JIS-Z-8722 satisfy the following formulas (C) to (E): Polyester film,
20 ≧ a ^* ≧ −50 (C)
50 ≧ b ^* ≧ −20 (D)
80 ≧ L ^* ≧ 30 (E)
(4) The colored polyester film according to any one of (1) to (3), wherein the total light transmittance is 50% or less,
(5) The colored polyester film according to any one of (1) to (4), which contains 0.1 to 30% by mass of an inorganic pigment based on 100% by mass of the entire colored polyester film,
(6) The colored polyester film according to any one of (1) to (5), wherein the pigment mass ratio in the film satisfies the following formula (F):
0.95 ≧ (white pigment) / (total pigment) ≧ 0.2 (F)
(7) The colored polyester film according to any one of (1) to (6), wherein the entire colored polyester film is 100% by mass and the oligomer is contained in an amount of 0.1 to 0.8% by mass.
(8) The colored polyester film according to any one of (1) to (7), comprising at least two layers of a base polyester (I) layer and a surface polyester (II) layer,
(9) The total surface polyester (II) layer is 100% by mass, and 0.1 to 0.5% by mass of ethylene terephthalate cyclic trimer is contained in the surface polyester (II) layer. A polyester film according to
(10) The polyester film according to (8) or (9), wherein the surface layer polyester (II) layer does not contain a colorant,
(11) The polyester film according to any one of (1) to (10), wherein the film has a melting point of 246 to 270 ° C.
(12) The colored polyester film according to any one of (1) to (11), which is biaxially oriented,
(13) The colored polyester film according to any one of (1) to (12), which is used for molding processing
It is.

  The colored polyester film of the present invention has a high glossiness and satisfies a predetermined color tone, so it has excellent design properties, and since it has a high glossiness, it is also easy to wash and has a long high designability. Since it can be maintained, it can be used for various purposes. For this reason, when a shaping | molding process is given after bonding together to a base material, or the film itself is shape-processed and used, the shaping | molding processed goods excellent in the designability can be provided.

  The colored polyester film of the present invention needs to have a glossiness of 70 to 200 on at least one side of the film. Here, the glossiness indicates a value of 60-degree specular gloss measured based on JIS Z-8741 (1997). If the glossiness is less than 70, the gloss of the film surface is not recognized, and the design is not only inferior, but also the cleaning property is deteriorated, and even after washing, the surface is difficult to remove. It becomes difficult to maintain sex. The glossiness is largely attributed to the surface shape of the film, and the glossiness can be increased by smoothing the surface of the film. In order to make the glossiness 70 or more, it is preferable that the center line average roughness is less than 20 nm. Here, the center line average roughness is a value measured with a contact-type two-dimensional roughness meter. In order to make the center line average roughness less than 20 nm, a colorant such as a pigment added to obtain a predetermined color tone or a particle having a small particle size such as a particle for controlling the handleability of the film is selected. Can be achieved. The particle size of the colorant and particles is preferably 2 μm or less.

  Further, even if the glossiness is larger than 200, the gloss is not substantially changed, and the effect of easy cleaning is almost the same, so it is not essential for practical use.

  More preferably, the glossiness of at least one surface of the film is 75 to 190, and most preferably 80 to 180.

The colored polyester film of the present invention needs to satisfy the following formula (A) in terms of a ^* value and b ^* value based on JIS Z-8722.
100 ≧ | a ^* | + | b ^* | ≧ 5 (A)
Here, the a ^* value and the b ^* value are values measured by the reflection method. If | a ^* | + | b ^* | <5, the color saturation of the film becomes low, and the color of the film becomes white or black, which is not preferable in appearance. Further, if 100 <| a ^* | + | b ^* |, the saturation is too high, resulting in an unnatural color tone, and conversely, the design may be deteriorated.

It is preferable that the a ^* value and the b ^* value satisfy the following formula (B) because the design property is further improved.
50 ≧ | a ^* | + | b ^* | ≧ 15 (B)
In the colored polyester film of the present invention, it is preferable that a ^* value, b ^* value, and L ^* value based on JIS-Z-8722 satisfy the following formulas (C) to (E). Here, the a ^* value, b ^* value, and L ^* value are values measured by the reflection method.
20 ≧ a ^* ≧ −50 (C)
50 ≧ b ^* ≧ −20 (D)
80 ≧ L ^* ≧ 30 (E)
When the a ^* value and b ^* value of the colored polyester film of the present invention satisfy the formulas (C) and (D), a clear color tone can be exhibited and the design can be further improved. It is more preferable that the a ^* value and the b ^* value satisfy the expressions (C ′) and (D ′), and it is most preferable that the expressions (C ″) and (D ″) are satisfied.
20 ≧ a ^* ≧ −40 (C ′)
15 ≧ a ^* ≧ −30 (C ″)
40 ≧ b ^* ≧ −20 (D ′)
30 ≧ b ^* ≧ −15 (D ″)
If the L ^* value of the colored polyester film of the present invention is less than 30, the light-shielding property is lowered and the concealing property may be inferior. When the colored polyester film of the present invention is used by being bonded to a base material, if the concealing property is low, the base material cannot be concealed, and the polyester film of the present invention itself is molded and processed as a container. When used, the contents cannot be concealed, so that the designability may be deteriorated, and the contents retainability may be affected. On the other hand, if it exceeds 80, the density increases due to the addition of a large amount of pigment into the film, and consequently, energy loss during transportation as a packaging material and other film properties are impaired. The L ^* value is more preferable if the expression (E ′) is satisfied, and most preferable if the expression (E ″) is satisfied.
75 ≧ L ^* ≧ 30 (E ′)
75 ≧ L ^* ≧ 35 (E ″)
In the colored polyester film of the present invention, in order for the a ^* value, b ^* value, and L ^* value based on JIS Z-8722 to satisfy the formulas (A) to (E), a colorant is added and the color is adjusted. The method can be preferably used.

A method for performing the toning is not particularly limited, but as a general toning work, the following procedure is often performed. 1. Look at the color swatch and determine the target color. 2. Select the colorant to be used. Select the amount of colorant to be mixed 4. 4. Mix them to make a sample 5. Compare sample color and color sample (visual and color measurement) 6. If the color is equal to the color sample, end the work, otherwise enter the correction work. Determine the tendency of difference between sample and color sample (from visual and color difference) 8. Select the colorant and the amount of mixture necessary for correction. The following 4 to 6 are repeated to adjust the target color. In order to improve the efficiency of these operations, CCM (Computer Color Matching) technology is also preferably used. With CCM, a colorant is selected in advance and its colorimetric data is registered in the computer, and the color sample is displayed. The color sample is immediately measured, and the data is sent to the computer. This is a technique for calculating a blending ratio of a colorant and blending a colorant based thereon.

The L ^* value is a change in brightness. The larger the value, the brighter the value, and the smaller the value, the darker. Further, the a ^* value is a change value of red and green colors. The larger the positive value, the red direction, and the negative value is the green direction. The b ^* value is a change value of yellow and blue colors. The larger the positive value, the yellow direction, and the negative value is the blue direction. In order to obtain a predetermined color tone satisfying the expressions (A) to (E), the color can be adjusted by adding a red, green, yellow or blue colorant. Write L ^* value is added a high colorant, a ^* value, the amount of change in the b ^* value becomes when many large, a ^* value, when you want significantly alter the b ^* values, L ^* value The use of high colorants tends to be advantageous.

  Examples of the colorant used include dyes, inorganic pigments, and organic pigments. However, since dyes tend to sublime from polyester and may contaminate the production process, inorganic and organic pigments are preferably used. Examples of inorganic pigments used include red pigments such as Bengala, molybdenum red, and cadmium red, orange pigments such as red-mouthed yellow lead and chrome permillion, blue pigments such as ultramarine, bitumen, cobalt blue, and cerulean blue, and oxidation. Examples thereof include green pigments such as chromium, pyridian, emerald green, and cobalt green, yellow pigments such as yellow lead, cadmium yellow, yellow iron oxide, and titanium yellow, and purple pigments such as manganese violet and mineral violet. Further, white pigments such as titanium oxide, barium sulfate, zinc white and zinc sulfate, and black pigments such as carbon black and black iron oxide may be added as long as the saturation is not significantly reduced. Examples of the organic pigment used include condensed azo, phthalocyanine, quinacridone, dioxazine, isoindolinone, quinophthalone, and anthraquinone.

  Inorganic pigments are more preferably used because they have better heat resistance than organic pigments. The colored polyester film of the present invention may heat the molded product during molding and preferably contains an inorganic pigment from the viewpoint of preventing discoloration during heating. In order to impart designability, the inorganic pigment is preferably contained in an amount of 0.1 to 30% by mass with respect to 100% by mass of the entire colored polyester film. More preferably, the content is preferably 0.2 to 25% by mass, and most preferably 0.5 to 20% by mass.

  The method of adding a colorant to the colored polyester film of the present invention and coloring is not particularly limited, but the colorant is melt-kneaded in advance in a polyester resin as a raw material at a high concentration, and at a predetermined concentration with a diluted resin during film formation. The masterbatch method which makes it become can be used preferably.

  Here, a specific method for manufacturing the master batch will be described. For example, a polyethylene terephthalate resin is freeze-pulverized at a low temperature, and a predetermined colorant is added to a powdered product, mixed uniformly, and then supplied to a vent type twin screw extruder and melt-kneaded. At this time, 0.01 to 1% by mass of stearyl stearate, magnesium stearylate or the like as a dispersion aid for the colorant may be added based on 100% by mass of the entire master batch. The resin thus colored and kneaded is extruded into a strand shape, cooled and solidified in water, and then cut to a desired size with a cutter to obtain a master batch. The colorant concentration in the masterbatch is preferably a high concentration from an economical viewpoint, for example, the total masterbatch is 100% by mass, preferably 30% by mass or more, etc. From the viewpoint of preventing uneven color, the colorant concentration in the master batch is preferably 1 to 30% by mass, and more preferably 1.5 to 20% by mass.

In the colored polyester film of the present invention, the pigment mass ratio in the film preferably satisfies the following formula (F).
0.95 ≧ (white pigment) / (total pigment) ≧ 0.2 (F)
Here, as the white pigment, the white pigment system shown in Pigment Handbook (edited by the Japan Pigment Technical Association) can be preferably used. Since the white pigment has a very large coloring power and hiding power, if (white pigment) / (total pigment) is less than 0.2, the light shielding performance is lowered and the hiding power may be inferior, which is not preferable. . On the other hand, if (white pigment) / (total pigment) is greater than 0.95, the whiteness of the film becomes too strong, the color tone becomes unnatural, and the design properties may deteriorate. It is not preferable.

The colored polyester film of the present invention is more preferably when the pigment mass ratio in the film satisfies the formula (F ′), and most preferably when it satisfies (F ″).
0.9 ≧ (white pigment) / (total pigment) ≧ 0.2 (F ′)
0.9 ≧ (white pigment) / (total pigment) ≧ 0.3 (F ″)
The total light transmittance of the colored polyester film of the present invention is preferably 50% or less. If the total light transmittance is higher than 50%, the light-shielding property is lowered and the concealing property is inferior. More preferably, the total light transmittance is 45% or less, and most preferably 40% or less.

  The method for setting the total light transmittance to the above range is not particularly limited, and for example, a method using a pigment having excellent concealability can be mentioned. As the pigment having excellent hiding properties, it is preferable to use white pigments such as titanium oxide, barium sulfate, zinc white, and zinc sulfate, and black pigments such as carbon black. Here, for these pigments having a concealing property, the addition amount in the film is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on 100% by mass of the entire film. .

  In addition, the opacity of the pigment largely depends on the particle size. When the pigment having a particle size of 0.1 to 0.3 μm is used, the opacity is increased. When it is larger than 0.3 μm, the opacity similarly decreases. Further, by increasing the opaque pigment concentration, the concealability can be further increased. As used herein, the particle size refers to the arithmetic average value of the major axis diameter. In addition, although the measuring method of a particle size is not specifically limited, For example, the cross section of a film is observed by observing an arbitrary number of particles by changing the location at a magnification of about 10,000 to 100,000 times using a scanning electron microscope or the like. The measured image can be measured by taking the image into an image analyzer and analyzing the image.

  The colored polyester film of the present invention preferably contains an oligomer in an amount of 0.1 to 0.8% by mass with the entire film as 100% by mass. The oligomer here refers to an ethylene terephthalate cyclic trimer. Ethylene terephthalate cyclic trimer is a kind of low molecular weight substance existing in polyethylene terephthalate resin, and is produced by intermolecular transesterification and intramolecular transesterification. The three monomers have a cyclic structure and occupy about 80% of the low molecular weight substance in the polyethylene terephthalate resin. The cyclic trimer can be extracted from an organic solvent such as chloroform, dioxane, xylene and separated from other low molecular weight substances by thin film chromatography, liquid chromatography, gel permeation chromatography, and the like.

  Although it is theoretically possible to make the oligomer content less than 0.1% by mass, it is not preferable because the production cost becomes enormous and disadvantageous economically. Moreover, when the amount exceeds 0.8% by mass, precipitation of a trimer and crystallized product are observed when heat treatment such as preheating step during molding processing, retort heat treatment or dry heat treatment after molding processing is performed, and appearance. There is a problem that damages. More preferably, it is 0.15-0.75 mass%, and if it is 0.2-0.7 mass%, it is the most preferable.

  As a method of setting the oligomer content in the above range, it is preferable to reduce the oligomer content in the raw resin stage before film formation. An example of the method is a solid phase polymerization method. That is, the polyester resin is pre-crystallized in air, an inert gas, or hot water at a temperature not lower than the glass transition point and not higher than the melting point. Thereafter, under reduced pressure or under an inert gas atmosphere, a range of (glass transition temperature +5) ° C. or higher and (melting point −5) ° C. or lower, preferably (glass transition temperature +10) ° C. or higher, (melting point −10 ) Solid phase polymerization is carried out in the range of ° C or below.

  Moreover, the method of heat-processing the resin solidified in water and the method of extracting an oligomer from resin solidified with the solvent can also be mentioned.

  In addition, a copolymerization or polymer blending method within a range that does not impair the heat resistance can be preferably used. For example, in the case of isophthalic acid copolymerized polyethylene terephthalate, it does not go through a special step such as solid phase polymerization. If the copolymerization rate is 0 mol%, the amount of oligomer is usually 1.1 to 1.2 mass%. When 5 mol% isophthalic acid is copolymerized, the amount of oligomer in the resin can be reduced to 1 mass% and 10 mol% when the copolymer is 0.9 mass%. However, in the case of these copolymerizations, the amount of oligomers having other compositions increases, so the copolymerization ratio of isophthalic acid to polyethylene terephthalate is preferably 5 mol% or less.

The colored polyester film of the present invention preferably comprises at least two layers of a base layer polyester (I) layer and a surface layer polyester (II) layer. Since it is possible to improve the characteristics of the colored polyester film by using a laminated film, it is a preferred embodiment. For example, the amount of cyclic trimer in the surface polyester (II) layer is extremely small, or polyester having high crystallinity. Can be used to suppress precipitation of the cyclic trimer on the surface when the colored polyester film of the present invention is heated.

  In order to achieve the above example, the colored polyester film of the present invention comprises an ethylene terephthalate cyclic trimer in the surface polyester (II) layer, 100 mass% of the entire surface polyester (II) layer, It is preferable to contain 0.5 mass%. When the content of the cyclic trimer in the surface polyester (II) layer is in the above range, the cyclic trimer when the preheating step during the molding process, the retort heat treatment after the molding process or the heat treatment such as the dry heat treatment is performed. This is preferable because the effect of suppressing precipitation on the surface is greatly enhanced. More preferably, it is 0.1-0.45 mass%, and if it is 0.1-0.4 mass%, it is the most preferable.

  In addition, when a pigment having a large particle size is added to obtain a predetermined color tone in the base polyester (I) layer, a surface polyester (II) layer containing no pigment is laminated to obtain high glossiness. The preferable color tone and glossiness can be easily achieved. Moreover, when it is set as said structure, the precipitation on the surface of a pigment at the time of using the pigment which is easy to precipitate on the surface with time, heating, etc. can also be suppressed.

  In order to achieve the above example, the colored polyester film of the present invention preferably contains no colorant in the surface polyester (II) layer. High glossiness can be achieved by not containing a colorant in the surface polyester (II) layer.

  When making a laminated film of two or more layers, the thickness of the surface layer is preferably 1 to 20% of the thickness of the entire film, more preferably 2 to 15%. As a method for producing such a laminated film, a method of performing melt extrusion using a plurality of extruders, joining them in a feed block installed on the top of the T die, and laminating can be preferably used. Here, the laminated film having two or more layers refers to A / B2 layers, A / B / A and A / B / C3 layers, and further laminated films.

  In addition, the colored polyester film of the present invention contains internal particles, inorganic particles and / or organic particles having an average particle diameter of 0.01 to 10 μm in addition to the inorganic pigment and organic pigment described above in order to improve the handleability and processability. It is preferable to contain 0.01-3 weight% with respect to the whole colored polyester film. Examples of the method for precipitating the internal particles include the techniques described in JP-A-48-61556, JP-A-51-12860, JP-A-53-41355, JP-A-54-90397, and the like. Can be adopted. In addition, other particles such as JP-B-55-20496 and JP-A-59-204617 can be used in combination. It should be noted that the use of particles having an average particle diameter exceeding 10 μm may cause defects in the film. Examples of the inorganic particles that can be used include wet and dry silica, colloidal silica, aluminum silicate, calcium phosphate, barium sulfate, aluminum oxide, mica, kaolin, and clay. Moreover, as organic particles, particles containing styrene, silicone, acrylic acids, methacrylic acids, polyesters, divinyl compounds and the like as constituent components can be used. Of these, inorganic particles such as wet and dry silica and alumina, and particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components are preferably used. Furthermore, two or more kinds of these internal particles, inorganic particles, and organic particles may be used in combination.

  Moreover, when setting it as a laminated film of two or more layers, you may add the said particle | grain for a handleability and workability improvement in the surface layer polyester (II) layer, if it is a grade which does not reduce glossiness.

  Here, the polyester resin constituting the colored polyester film of the present invention is a general term for polymer compounds in which the main bonds in the main chain are ester bonds, and usually a polycondensation reaction between a dicarboxylic acid component and a glycol component. Can be obtained. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, and 5-sodiumsulfoisophthalic acid. Aromatic dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexyne dicarboxylic acid and other alicyclic dicarboxylic acids, p-oxybenzoic acid, etc. The oxycarboxylic acid of these can be mentioned.

  Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-butanediol, 1,6-butanediol, Aliphatic glycols such as hexanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polyoxyalkylene glycols such as polytetramethylene glycol, alicyclic glycols such as 1,4-cyclohexanedimethanol, bisphenol A, bisphenol S And aromatic glycols. Two or more of these dicarboxylic acid components and glycol components may be used in combination. The polyester used in the present invention may be one type of polyester or a blend of two or more types of polyester.

  Particularly preferred polyester is mechanical strength, workability, and thermal properties, with terephthalic acid or dimethyl terephthalate and ethylene glycol as the main constituents, which can be obtained by polycondensation reaction by esterification or transesterification. It is preferable because of its excellent humidity characteristics. Here, “mainly” means that the ethylene terephthalate component in the polyester is 30 mol% or more.

  The colored polyester film of the present invention preferably has a melting point of 246 to 270 ° C. from the viewpoints of heat resistance and resin handling properties. Here, the melting point of the colored polyester film of the present invention is an endothermic peak temperature expressed by a melting phenomenon when measured at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter (DSC). When a polyester resin having a different composition is blended and used as a film, a plurality of endothermic peaks due to melting may appear. In that case, the endothermic peak temperature appearing at the highest temperature is set to the temperature of the colored polyester film of the present invention. The melting point. The melting point is more preferably 250 to 270 ° C. As a method of setting the temperature range to apply the melting point of the polyester film, it is preferable to set the melting point in the range of 246 to 270 ° C. in the polyester resin stage used at the time of film formation, and even when a polyester resin having a different composition is used. In order to suppress a melting point drop due to a transesterification reaction between resins during melt kneading even when a polyester resin having a melting point of 246 ° C. or higher is used and a polyester resin having a low melting point is used. In order to deactivate the catalyst remaining in the resin in advance or to reduce the catalytic ability, a phosphorus compound is added. Further, by preparing a polyester resin having a low residual catalyst amount, the melting point can be adjusted to a range of 246 to 270 ° C.

  In producing the polyester resin constituting the polyester film of the present invention, a reaction catalyst and an anti-coloring agent can be used. Examples of the reaction catalyst include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, and titanium compound germanium compounds. Although a compound etc. can be used, in this invention, it does not specifically limit to these.

  In general, it is preferable to add an antimony compound, a germanium compound and / or a titanium compound as a polymerization catalyst at an arbitrary stage before the production of the polyester is completed. As such a method, for example, when a germanium compound is taken as an example, a method of adding a germanium compound powder as it is, or a method of dissolving a germanium compound in a glycol component which is a starting material of polyester, and using it. Can do.

  Examples of such germanium compounds include germanium dioxide, germanium hydroxide hydrate or germanium alkoxide compounds such as germanium tetramethoxide and germanium ethyleneglycoxide, germanium phonoxide compounds, phosphorous such as germanium phosphate and germanium phosphite. An acid-containing germanium compound, germanium acetate, or the like can be used. Of these, germanium dioxide is preferably used.

  The antimony compound is not particularly limited, and for example, an oxide such as antimony trioxide, antimony acetate and the like can be used. Further, the titanium compound is not particularly limited, but titanium tetraalkoxide such as titanium tetraethoxide and titanium tetrabutoxide can be preferably used.

  The method for producing the colored polyester film of the present invention is not particularly limited. For example, after drying the polyester resin as necessary, it is supplied to a melt extruder, extruded into a sheet form from a slit die, and a system such as electrostatic application Can be brought into close contact with the casting drum, cooled and solidified to obtain an unstretched sheet. The unstretched sheet thus obtained may be used as it is without being wound, but the colored polyester film of the present invention is biaxial for the purpose of increasing toughness, dimensional stability, heat resistance and mechanical strength. It is preferable that the film is stretched and biaxially oriented. As a biaxial stretching method, the film is stretched in the longitudinal direction and then stretched in the width direction, or the film is stretched in the width direction and then stretched in the longitudinal direction, or the longitudinal direction and the width direction of the film are Stretching can be performed by a simultaneous biaxial stretching method that stretches substantially simultaneously.

  Such a stretching method may be simultaneous biaxial stretching or sequential biaxial stretching. That is, a method is employed in which an unstretched sheet is stretched and heat-treated in the longitudinal direction and the width direction of the film to obtain a film having a desired plane orientation degree. Among these methods, the tenter method is preferable in terms of film quality, and after stretching in the longitudinal direction, a sequential biaxial stretching method in which the film is stretched in the width direction, or the longitudinal direction and the width direction are stretched almost simultaneously. The simultaneous biaxial stretching method is preferably used from the viewpoint of suppressing variation in the plane orientation coefficient and suppressing unevenness in thickness.

  In such a stretching method, the stretching ratio employed is preferably 1.6 to 4.2 times, more preferably 2.4 to 4.0 times in each direction. The stretching speed is desirably 100 to 200000% / min, and the stretching temperature can be any temperature as long as it is in the temperature range of the glass transition point of the polyester to the glass transition point + 100 ° C., preferably 80 to 170 ° C., particularly preferably, the stretching temperature in the longitudinal direction is 90 to 150 ° C., and the stretching temperature in the width direction is 95 to 150 ° C. In order to impart a very excellent moldability to the film, it is particularly preferable that the stretching temperature in the longitudinal direction is 100 to 130 ° C. It is preferable to stretch the film after preheating in a range that does not change, from the viewpoints of excellent flatness by uniform stretching and expression of excellent moldability by suppressing uneven orientation. Further, the stretching may be performed a plurality of times in each direction.

  Furthermore, the film can be heat-treated after biaxial stretching. This heat treatment can be performed by any method such as in an oven or on a heated roll. The heat treatment temperature can be any temperature within the range of the stretching temperature to the melting point of the raw material, but is preferably a heat treatment temperature of 160 to 235 ° C. from the viewpoint of molding processability and impact resistance. If the temperature is lower than this temperature, the impact resistance is deteriorated. If the temperature is higher, the moldability may be deteriorated. Further, the heat treatment time can be arbitrarily set within a range not deteriorating other characteristics, but it is usually preferable to carry out for 1 to 30 seconds. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction.

  The colored polyester film of the present invention preferably has a film thickness of 5 to 500 μm. When used as an unstretched film, it is more preferable in it being 100-500 micrometers. Moreover, even if it is a biaxially oriented film, when it is used for a food container etc. with a film single-piece | unit as a secondary process after film manufacture, it is more preferable if it is 75-250 micrometers, and if it is 100-200 micrometers, it is especially preferable. Furthermore, when it is used by being bonded to another substrate, it is preferably 6 to 38 μm, more preferably 7 to 25 μm, and particularly preferably 8 to 20 μm.

  The colored polyester film of the present invention is preferably used for molding processing. For example, the molding process is an application in which processing is performed by bonding to a substrate or processing the film itself into a container or the like. Although it does not specifically limit with a base material here, Natural materials, such as a resin sheet, paper, and wood, etc. are mentioned.

  When the colored polyester film of the present invention is used by being bonded to a base material, a configuration in which the surface having a high glossiness and the opposite surface side are bonded to the base material is preferable in terms of the design properties of the bonded product. In addition, when the colored polyester film of the present invention is processed and used in the form of a container or the like, it is processed so that the surface on the outer side of the container has a high glossiness in terms of the design of the processed product. It is preferable.

(Evaluation of the physical properties)
The physical properties and characteristics of the polymer and film were measured and evaluated by the following methods.

(1) Color tone Based on JIS-Z-8722 (2000), each using a spectroscopic color difference meter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., light source halogen lamp 12V4A, 0 ° to −45 ° post-spectral method) The color tone (L * value, a ^* value, b ^* value) of the film was measured by the reflection method. The measurement was performed in an atmosphere at a temperature of 23 ° C. and a humidity of 65%. Measurement was carried out by selecting five arbitrary positions on the film, and the average value was adopted.

(2) Glossiness According to the method prescribed in JIS-Z-8741 (1997), 60 ° specular glossiness was measured using a digital variable angle glossiness meter UGV-5D manufactured by Suga Test Instruments. The measurement was performed at n = 5, and the average value excluding the maximum value and the minimum value was defined as the glossiness.

(3) Total light transmittance It measured with the haze meter HGM-2DP (Suga Test Instruments Co., Ltd.). Measurement was performed at n = 5, and an average value excluding the maximum value and the minimum value was defined as the total light transmittance.

(4) Pigment content in film The content of the inorganic pigment was determined by fluorescent X-ray measurement as the residual amount of the metal element. The quantification was performed using a calibration curve of the strength and each element amount prepared using a sample with a known metal amount quantified in advance using an atomic absorption method or the like. The content of the organic pigment was determined by measuring the colorant concentration using ¹ H-NMR and ¹³ C-NMR after dissolving the film in hexafluoroisopropanol (HFIP). The organic pigment can be identified by changing the excitation wavelength of the Raman band from the pigment in the film using the resonance Raman effect in Raman spectroscopy and comparing it with the Raman band of the pigment standard sample. it can. In addition, when measuring pigment content in surface layer polyester (II) layer, the sample was extract | collected by scraping only the surface layer polyester (II) layer part, and the measurement was performed.

(5) Amount of oligomer in film 100 mg of film was dissolved in 1 mL of orthochlorophenol, and the amount of cyclic trimer was measured by liquid chromatography (Varian model 8500). In addition, when measuring the amount of the cyclic trimer in the surface layer polyester (II) layer, a sample was collected by scraping only the surface layer polyester (II) layer portion, and the measurement was performed.

(6) Melting | fusing point of film It measured using the differential scanning calorimeter (the Seiko Denshi Kogyo make, RDC220). When 5 mg of the sample is used as a sample and there are multiple endothermic peaks with the endothermic peak temperature at 25 ° C. up to 300 ° C. as the melting point, the peak temperature of the endothermic peak on the highest temperature side is the melting point It was.

(7) Particle size The cross section of the film was observed with a field emission scanning electron microscope (manufactured by JEOL, JSM-6700F) at 100 arbitrary particles (100,000 times), and the image was taken into an image analyzer. It is. From the captured image, the major axis diameter was measured, and the arithmetic average value was obtained to determine the particle diameter.

(8) Designability Show the film sample to 25 people, have a high designability, no designability, and evaluate in three stages, neither design, 4 points with high designability, 2 points that are neither, no designability The score was given as 0 and evaluated as follows.
○: 80 points or more Δ: 50 to 80 points ×: less than 50 points.

(9) Easy cleaning After storing the film in an atmosphere of 23 ° C. and 65% RH for one week, a field emission scanning electron microscope (manufactured by JEOL Ltd., JSM-6700F) was used to remove any 10 locations on the film surface. Observation (350 times), the number of dusts with a diameter of 5 μm or more was counted, and the average value was calculated. Then, the film surface was wiped off with an industrial wiper (Kimwipe, manufactured by Crecia Co., Ltd., wiper S-200) (3 times in the vertical and horizontal directions). Thereafter, similarly, arbitrary 10 locations on the film surface were observed, and the reduction rate of the number of dusts having a diameter of 5 μm or more before and after wiping was calculated from the following formula and evaluated.
Decrease rate (%)
= (Number of dust before wiping-number of dust after wiping) / (number of dust before wiping) × 100
○: Reduction rate of 80% or more △: Reduction rate of 40-80%
X: Reduction rate is less than 40%.

(10) Oligomer precipitation resistance The film was framed and heat-treated at 120 ° C. for 2 hours in a hot air oven. The fill surface after the heat treatment was observed (500 times) with a field emission scanning electron microscope (manufactured by JEOL, JSM-6700F) and evaluated according to the following criteria.
A: No precipitation of oligomers or the like was observed on the film surface.
Δ: Oligomer precipitation was observed on the film surface.
X: Powder was deposited just by touching with hands.

(11) Thermoformability Using a far infrared heater heated to 300 ° C, the film is heated to a temperature of (melting point of the film-20) ° C and vacuum-molded using a cylindrical mold (bottom diameter 50 mm). To form a film into a container. The state of being molded along the mold was evaluated according to the following criteria using the molding degree (drawing ratio: molding height / bottom diameter).
○: Molding was possible with a drawing ratio of 0.7 or more.
Δ: Molding was possible with a drawing ratio of 0.7 to 0.3.
X: Breakage occurred and molding could not be performed with a drawing ratio of 0.3.

(Production method of polyester)
The polyester resin used in the following experiments was produced as follows.

(Polyester W)
0.04 parts by mass of manganese acetate is added to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, the temperature is gradually raised, and finally transesterification is performed while distilling methanol at 220 ° C. It was. Next, 0.025 parts by mass of 85% phosphoric acid aqueous solution and 0.02 parts by mass of germanium dioxide were added, and the temperature was gradually raised and reduced. Finally, the temperature was raised to 290 ° C. and 1 hPa, and the intrinsic viscosity was 0. The polycondensation reaction was carried out until it became .67, then discharged into a strand, cooled, and cut to obtain polyethylene terephthalate (polyester W).

(Polyester X)
Polyester W was subjected to solid-phase polymerization using a rotary vacuum polymerization apparatus at 230 ° C. under a reduced pressure of 1 hPa until the intrinsic viscosity became 0.75, whereby polyester X was obtained.

(Polyester Y)
A mixture of 100 parts by mass of terephthalic acid and 110 parts by mass of 1,4-butanediol was heated to 140 ° C. under a nitrogen atmosphere to obtain a homogeneous solution, and then 0.054 parts by mass of tetra-n-butyl orthotitanate. Then, 0.054 parts by mass of monohydroxybutyltin oxide was added to carry out an esterification reaction. Next, 0.066 parts by mass of tetra-n-butyl orthotitanate was added and a polycondensation reaction was performed under reduced pressure to prepare a polybutylene terephthalate resin having an intrinsic viscosity of 0.88. Thereafter, crystallization was performed at 140 ° C. in a nitrogen atmosphere, followed by solid phase polymerization at 200 ° C. for 6 hours in a nitrogen atmosphere to obtain a polybutylene terephthalate resin (polyester Y) having an intrinsic viscosity of 1.20.

(Polyester Z)
To a mixture of 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol and 7 parts by weight of 1,4-cyclohexanedimethanol, 0.04 parts by weight of manganese acetate is added, and the temperature is gradually raised. Transesterification was carried out while distilling methanol at 0 ° C. Next, 0.045 parts by mass of 85% phosphoric acid aqueous solution and 0.01 parts by mass of germanium dioxide were added, and the temperature was gradually raised and reduced. Finally, the temperature was raised to 275 ° C. and 1 hPa, and the intrinsic viscosity was reduced. The polycondensation reaction was carried out until 0.67, and then discharged into a strand, cooled, and cut to obtain a polyethylene terephthalate resin copolymerized with 4 mol% of 1,4-cyclohexanedimethanol. The polymer was cut into cubes having a diameter of 3 mm, and solid phase polymerization was performed using a rotary vacuum polymerization apparatus under a reduced pressure of 1 hPa at 225 ° C. until the intrinsic viscosity became 0.8, whereby polyester Z was obtained.

(Pigment Master A)
Polyester W freeze-pulverized into powder and titanium oxide having an average particle size of 0.2 μm are mixed at a mass ratio of 50:50, and mixed uniformly, then supplied to a twin-screw vent type extruder, melt-kneaded, Extruded into a strand, cooled in water, then cut into a chip to obtain Pigment Master A.

(Pigment Master B)
Polyester W freeze-pulverized into powder and titanium yellow are mixed at a mass ratio of 75:25 and mixed uniformly, then supplied to a twin-screw vent type extruder, melt kneaded, extruded into a strand, and cooled in water Thereafter, it was cut into chips to obtain Pigment Master B.

(Pigment Master C)
Polyester W freeze-pulverized into powder and Bengala are mixed at a mass ratio of 95: 5 and mixed uniformly, then supplied to a twin-screw vent type extruder, melt-kneaded, extruded into a strand, and cooled in water The pigment master C was obtained by cutting into chips.
(Pigment Master D)
Polyester W freeze-pulverized into powder and carbon black are mixed at a mass ratio of 98.5: 1.5 and mixed uniformly, then supplied to a twin-screw vent type extruder, melt-kneaded, and extruded into a strand. After cooling in water, it was cut into chips to obtain Pigment Master D.

(Pigment Master E)
Polyester W freeze-pulverized into powder and ultramarine are mixed at a mass ratio of 95: 5 and mixed uniformly, then supplied to a twin-screw vent type extruder, melt-kneaded, extruded into a strand, and cooled in water The pigment master E was obtained by cutting into chips.

(Pigment Master F)
Polyester W freeze-pulverized into powder and chromium oxide are mixed at a mass ratio of 95: 5 and mixed uniformly, then supplied to a twin-screw vent type extruder, melt kneaded, extruded into a strand, and cooled in water Thereafter, it was cut into chips to obtain a pigment master F.

(Pigment Master G)
Polyester W freeze-pulverized into powder and condensed azo organic pigment Color Index Pigment Yellow 180 are mixed at a mass ratio of 95: 5 and mixed uniformly, then supplied to a twin-screw vent extruder and melt-kneaded. Then, it was extruded into a strand shape, cooled in water, then cut into a chip shape, and a pigment master G was obtained.

(Particle Master P)
0.04 parts by mass of manganese acetate is added to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, the temperature is gradually raised, and finally transesterification is performed while distilling methanol at 220 ° C. It was. Subsequently, 0.025 mass part of 85% phosphoric acid aqueous solution and 0.02 mass part of germanium dioxide were added. Further, an ethylene glycol slurry of wet silica agglomerated particles having an average particle size of 2.2 μm is added so that the particle concentration becomes 2% by mass, the temperature is gradually raised and reduced, and finally the temperature is raised to 290 ° C. and 1 hPa. Then, the pressure was reduced and a polycondensation reaction was performed until the intrinsic viscosity became 0.63, and then the particles were discharged in a strand, cooled, and cut to obtain a particle master Q.

(Particle Master Q)
0.04 parts by mass of manganese acetate is added to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, the temperature is gradually raised, and finally transesterification is performed while distilling methanol at 220 ° C. It was. Subsequently, 0.025 mass part of 85% phosphoric acid aqueous solution and 0.02 mass part of germanium dioxide were added. Further, an ethylene glycol slurry of wet silica agglomerated particles having an average particle size of 4 μm is added so that the particle concentration becomes 6% by mass, the temperature is gradually raised and reduced, and finally the temperature is raised to 290 ° C. and 1 hPa. Then, a polycondensation reaction was carried out until the intrinsic viscosity became 0.63, and then discharged into a strand, cooled, and cut to obtain a particle master Q.

Example 1
It was set as the two-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, the weight ratio of polyester W, polyester Y, pigment master A, pigment master B, pigment master C, pigment master D, and particle master P is 36.2: 30: 3. A mixture of 8: 16: 2: 8: 4 was used. As the polyester resin constituting the surface layer, polyester X and particle master P were mixed and used at a mass ratio of 96: 4.

  Each mixed polyester resin was individually dried in a vacuum dryer at 180 ° C. for 4 hours, and after sufficiently removing moisture, supplied to separate single screw extruders, melted at 280 ° C., and filtered through separate paths. After removing the foreign matter and leveling the extrusion amount through a gear pump, the base layer / surface layer (lamination thickness ratio 10.5: 1.5) is laminated in the feed block installed on the top of the T-die. After that, the sheet was discharged from a T die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.2 times in the longitudinal direction at a film temperature of 100 ° C. and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 70 ° C. and a stretching temperature of 95 ° C. with a tenter type horizontal stretching machine, and the temperature was maintained at 230 ° C. for 5 seconds while relaxing 4% in the width direction in the tenter. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 12 μm.

(Example 2)
It was set as the two-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As the polyester resin constituting the base layer, the mass ratio of polyester X, polyester Y, pigment master A, pigment master C, pigment master D, pigment master G, and particle master P is 56: 10: 8: 8: 6: 8: 4 was mixed and used. As the polyester resin constituting the surface layer, polyester X and particle master P were mixed and used at a mass ratio of 96: 4.

  A biaxially oriented film having a film thickness of 15 μm was obtained in the same manner as in Example 1 except that the raw material was used and the base layer / surface layer (lamination thickness ratio 13: 2) was used.

(Example 3)
It was set as the 2 layer laminated film of the base layer and surface layer containing a coloring agent. As a polyester resin constituting the base layer, polyester X, polyester Y, pigment master A, pigment master B, pigment master D, and particle master Q are mixed at a mass ratio of 51: 20: 15: 5: 5: 4. Used. As the polyester resin constituting the surface layer, polyester X, pigment master E, and particle master Q were mixed and used in a mass ratio of 91: 5: 4.

  A biaxially oriented film having a film thickness of 20 μm was obtained in the same manner as in Example 1 except that the above raw materials were used and the base layer / surface layer (lamination thickness ratio 18: 2) was used.

Example 4
It was set as the two-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As polyester resin constituting the base layer, polyester X, polyester Y, pigment master A, pigment master E, pigment master F, and particle master Q are mixed at a mass ratio of 46: 20: 10: 10: 10: 4. Used. As the polyester resin constituting the surface layer, polyester W, pigment master Z, and particle master Q were mixed and used at a mass ratio of 36: 61: 3.

  A biaxially oriented film having a film thickness of 13 μm was obtained in the same manner as in Example 1 except that the raw material was used and the base layer / surface layer (lamination thickness ratio 11: 2) was used.

(Example 5)
It was set as the two-layer laminated film of the layer (base layer) containing an organic pigment, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, polyester X, pigment master A, pigment master E, and pigment master F were mixed at a mass ratio of 60: 15: 15: 10. Polyester X was used as the polyester resin constituting the surface layer.

  Each mixed polyester resin is individually dried in a vacuum dryer at 180 ° C for 4 hours, and after sufficiently removing moisture, supplied to a separate single-screw extruder, melted at 280 ° C, and filtered through separate paths. After passing through the gear pump, removing the foreign matter and leveling the extrusion amount, after laminating so as to be the base layer / surface layer (lamination thickness ratio 130: 20) in the feed block installed on the top of the T die, The sheet was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film having a film thickness of 150 μm.

(Example 6)
It was set as the three-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, polyester W, polyester Z, pigment master A, pigment master C, pigment master D, pigment master E, and particle master P are in a mass ratio of 24: 40: 8: 10: A mixture of 4: 10: 4 was used. As the polyester resin constituting the surface layer, polyester X and particle master P were mixed and used at a mass ratio of 96: 4.

  Each mixed polyester resin was individually dried in a vacuum dryer at 180 ° C. for 4 hours, and after sufficiently removing moisture, supplied to separate single screw extruders, melted at 280 ° C., and filtered through separate paths. After removing the foreign matter and leveling the extrusion amount through the gear pump, the layers are laminated so that the surface layer / base layer / surface layer (lamination thickness ratio 1: 10: 1) is in the feed block installed on the top of the T-die. After that, the sheet was discharged from a T die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.2 times in the longitudinal direction at a film temperature of 105 ° C. and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 120 ° C. with a tenter type horizontal stretching machine, and the temperature was kept at 215 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 12 μm.

(Example 7)
Polyester X, pigment master A, and pigment master G were mixed at a mass ratio of 70:20:10 and dried in a vacuum dryer at 180 ° C. for 4 hours to sufficiently remove moisture. Then, it supplied to the single screw extruder, melted at 280 ° C., and discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film having a film thickness of 100 μm.

(Example 8)
It was set as the two-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, polyester Z, pigment master F, pigment master G, and particle master P were mixed and used at a mass ratio of 79: 10: 10: 1. As the polyester resin constituting the surface layer, polyester X and particle master P were mixed and used at a mass ratio of 98: 2.

  A biaxially oriented film having a film thickness of 20 μm was obtained in the same manner as in Example 1 except that the above raw materials were used and the base layer / surface layer (lamination thickness ratio 18: 2) was used.

(Comparative Example 1)
It was set as the two-layer laminated film of the layer (base layer) containing a coloring agent, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, polyester X, pigment master A, and particle master P were mixed at a mass ratio of 66: 30: 4. As the polyester resin constituting the surface layer, polyester X and particle master P were mixed and used at a mass ratio of 96: 4.

  Using the raw materials, a biaxially oriented film having a film thickness of 12 μm was obtained in the same manner as in Example 1.

(Comparative Example 2)
Polyester W, pigment master G, and particle master P were mixed at a mass ratio of 80: 15: 5 and dried in a vacuum dryer at 180 ° C. for 4 hours to sufficiently remove moisture. Then, it supplied to the single screw extruder, melted at 280 ° C., and discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically, and was brought into close contact with the cooling drum to obtain an unstretched film.

  Next, the film temperature was raised with a heating roll before stretching in the longitudinal direction, and finally the film was stretched 3.2 times in the longitudinal direction at a film temperature of 105 ° C. and immediately cooled with a metal roll whose temperature was controlled at 40 ° C. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 120 ° C. with a tenter type horizontal stretching machine, and the temperature was kept at 215 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 20 μm.

(Comparative Example 3)
It was set as the three-layer laminated film of the layer (base layer) containing an organic pigment, and the layer (surface layer) which does not contain. As a polyester resin constituting the base layer, polyester X, pigment master A, pigment master D, and particle master Q were mixed in a mass ratio of 46: 20: 4: 30. As a polyester resin constituting the surface layer, polyester X and particle master Q were mixed and used at a mass ratio of 70:30.

  Each mixed polyester resin was individually dried in a vacuum dryer at 180 ° C. for 4 hours, and after sufficiently removing moisture, supplied to separate single screw extruders, melted at 280 ° C., and filtered through separate paths. After removing the foreign matter and leveling the extrusion amount through the gear pump, the layers are laminated so that the surface layer / base layer / surface layer (lamination thickness ratio 2: 16: 2) is formed in the feed block installed on the top of the T die. After that, the sheet was discharged from a T die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.2 times in the longitudinal direction at a film temperature of 95 ° C. and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 120 ° C. with a tenter type horizontal stretching machine, and the temperature was kept at 215 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 20 μm.

  The colored polyester film of the present invention is suitable for molding processing applications such as bonding to a base material, or processing the film itself and molding it into a container. Since the molded article using the colored polyester film of the present invention is very excellent in design properties and also in easy cleaning properties, high design properties can be maintained for a long time. Therefore, specifically, it is suitable for packaging materials, packaging containers, and the like.

Claims (13)

A colored polyester film, wherein the glossiness of at least one surface of the film is 70 to 200, and a ^* value and b ^* value based on JIS-Z-8722 satisfy the following formula (A):
100 ≧ | a ^* | + | b ^* | ≧ 5 (A) The colored polyester film according to claim 1, wherein a ^* value and b ^* value based on JIS-Z-8722 satisfy the following formula (B).
50 ≧ | a ^* | + | b ^* | ≧ 15 (B) The colored polyester film according to claim 1 or 2, wherein a ^* value, b ^* value, and L ^* value based on JIS-Z-8722 satisfy the following formulas (C) to (E).
20 ≧ a ^* ≧ −50 (C)
50 ≧ b ^* ≧ −20 (D)
80 ≧ L ^* ≧ 30 (E) The colored polyester film according to any one of claims 1 to 3, wherein the total light transmittance is 50% or less. The colored polyester film according to any one of claims 1 to 4, wherein the inorganic pigment is contained in an amount of 0.1 to 30% by mass based on 100% by mass of the entire colored polyester film. The colored polyester film according to any one of claims 1 to 5, wherein the pigment mass ratio in the film satisfies the following formula (F).
0.95 ≧ (white pigment) / (total pigment) ≧ 0.2 (F) The colored polyester film according to any one of claims 1 to 6, wherein the entire colored polyester film is 100% by mass and the oligomer is contained in an amount of 0.1 to 0.8% by mass. The colored polyester film according to claim 1, comprising at least two layers of a base polyester (I) layer and a surface polyester (II) layer. The surface polyester (II) layer is 100% by mass as a whole, and the surface polyester (II) layer contains 0.1 to 0.5% by mass of an ethylene terephthalate cyclic trimer. Polyester film. The polyester film according to claim 8 or 9, wherein the surface polyester (II) layer does not contain a colorant. The polyester film according to claim 1, wherein the melting point of the film is 246 to 270 ° C. The colored polyester film according to claim 1, wherein the colored polyester film is biaxially oriented. It uses for a shaping | molding process use, The colored polyester film in any one of Claims 1-12 characterized by the above-mentioned.