JP2019056061A - Colored polyester film, supporting body for inspection, and light-shielding member - Google Patents

Abstract

To provide a colored polyester film capable of easily performing a defect inspection at a high level as a supporting body for inspection when producing various kinds of display-composing members such as a polarization plate for LCD, a retardation plate, an organic EL-composing member, and a touch panel-composing member.SOLUTION: The colored polyester film comprises polyester, a coloring agent, and a resin composition containing a particle having an average particle size of 3.5 μm or more, where the transmission density is 1.0 or more, and the absolute reflectivity in a wave length region of 400 nm-800 nm is 6.0% or more.SELECTED DRAWING: None

Description

  The present invention relates to a colored polyester film. More specifically, the present invention relates to, for example, a polarizing plate used for a liquid crystal display (hereinafter abbreviated as LCD), an LCD component such as a retardation plate, an organic electroluminescence (hereinafter abbreviated as organic EL) component. The present invention relates to a colored polyester film suitable as an inspection support for various display structural members such as a touch panel structural member or a light shielding member for various optical devices such as a camera, a video camera, a copying machine, and a developing machine.

  Conventionally, a functional film based on a polyester film has been used as a member for manufacturing various display constituent members such as a polarizing plate for LCD, a retardation plate, and an organic EL constituent member.

  Among them, in the inspection process with optical evaluation, when the member is inspected by transmitting light, the member is inspected in a state of being bonded to a polyester film in which an adhesive layer is laminated as an inspection support. . At this time, if the transparency of the polyester film used for the inspection support is high, it may be difficult to detect a foreign substance to be detected due to glare of the film itself.

  Therefore, when optical evaluation is performed with a laminated structure in which the member and the inspection support are bonded, a light-shielding property is imparted by using a colored polyester film provided with a colored layer on the polyester film used in the inspection support. Since the glare of the film is suppressed, the inspection accuracy is improved.

  Further, since the colored polyester film has a light shielding property, it is also used as a light shielding member for various optical devices such as a camera, a video camera, a copying machine, and a developing machine. Conventionally, metals have been used for light shielding members such as shutters and diaphragms, but with the reduction in size, weight, and cost, colored polyester films are increasingly used.

  Patent Document 1 suggests the existence of a technical problem in which reflected light from the back side of the polyester film base material becomes an obstacle to inspection when coating defects are inspected. As a countermeasure against the technical problem, a countermeasure is proposed in which oil-based ink is simply applied to a polyester film on the back surface.

JP 2014-184656 A

However, the technique of Patent Document 1 lacks the stability of inspection due to the nature of application of oil-based ink, and the area of application of oil-based ink to the film increases as the area to be inspected increases. As a result, depending on the location where oil-based ink is applied, density unevenness may occur and problems such as poor uniformity may occur, so when a high level of defect inspection is required in a large area The method was unsuitable.
For this reason, a polyester film having both a light shielding property and an antireflection property at a higher level is particularly required as an inspection support.

  The present invention has been made in view of the above circumstances, and the problem to be solved is as an inspection support when manufacturing various display components such as a polarizing plate for LCD, a retardation plate, an organic EL component, a touch panel component, etc. Provided is a colored polyester film that can be easily inspected for defects at a high level.

  As a result of intensive studies in view of the above-described actual situation, the present inventors have found that the above-mentioned problems can be easily solved by using a colored polyester film having a specific configuration, and have completed the present invention.

  That is, the gist of the present invention consists of polyester, a colorant, and a resin composition containing particles having an average particle size of 3.5 μm or more, and has an absolute reflection in a wavelength region of 400 nm to 800 nm with a transmission density of 1.0 or more. It exists in the colored polyester film characterized by a rate being 6.0% or less.

  When the colored polyester film according to the present invention is used, for example, when used as an inspection support through an adhesive layer, defect detection is facilitated in an inspection process involving optical evaluation such as foreign object inspection. Further, in the process of transporting the colored polyester film by the roll-to-roll method, since the scratch caused by the friction between the roll and the film can be suppressed, the above inspection is not hindered and the industrial value is high.

[Colored polyester film]
Hereinafter, the present invention will be described in more detail.
The colored polyester film of the present invention may have a single layer structure or a laminated structure of two or more layers.

  The polyester used for the colored polyester film may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyester includes polyethylene terephthalate (PET) and the like. On the other hand, examples of the dicarboxylic acid component of the copolyester include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and the like. One kind or two or more kinds of glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like can be mentioned. In any case, the term “polyester” as used in the present invention refers to a polyester having an ethylene terephthalate unit of usually 60 mol% or more, preferably 80 mol% or more.

In the colored polyester film, it is necessary to contain a colorant in order to impart light shielding properties.
When the colorant in the present invention is in the form of particles, the colorant has a primary particle diameter of 0.001 to 3 μm. The primary particle size is preferably 0.005 to 2 μm, more preferably 0.01 to 1.5 μm.
When the primary particle size is 0.001 μm or more, the particles in the film are dispersed, so that color unevenness can be suppressed. On the other hand, the variation in the light shielding performance in the film width direction is suppressed by being 3 μm or less.

The colorants can be used alone or in combination of two or more. The content of the colorant is preferably 0.01 to 10% by weight, more preferably 0.05 to 7.5% by weight, and still more preferably 0.1 to 5% by weight.
When the content is 0.01% by weight or more, the content is sufficiently colored, and a desired light-shielding property can be obtained. On the other hand, when it is 10% by weight or less, sufficient productivity can be obtained.

Specific examples of the colorant include dyes and pigments.
The dyes contained in the colored polyester film can be classified into natural dyes and synthetic dyes, and examples of natural dyes include indigo (indigo). Synthetic dyes include azo dyes, anthraquinone dyes, indigoid dyes, sulfur dyes, triphenylmethane dyes, pyrazolone dyes, stilbene dyes, diphenylmethane dyes, xanthene dyes, alizarin dyes, acridine dyes, quinoneimine dyes (for example, azine dyes, oxazine dyes) , Thiazine dyes), thiazole dyes, methine dyes, nitro dyes, nitroso dyes, cyanine dyes and the like.

  The pigments contained in the colored polyester film can be classified into organic pigments and inorganic pigments. Examples of organic pigments include phthalocyanine-based, dioxazine-based, and anthraquinone-based pigments, and typical examples include quinacridone, watch ang red, and dioxazine violet. Examples of inorganic pigments include titanium white, zinc white, lead white, carbon black, bengara, vermilion, cadmium red, yellow lead, ultramarine, cobalt blue, cobalt purple, zinc chromate and the like.

Among the colorants, it is preferable to use carbon black particles in that the light shielding property and the antireflection property in the inspection wavelength region (400 nm to 800 nm) can be efficiently obtained with respect to the added amount. Specific examples of the carbon black particles include channel black, thermal black, furnace black and the like. The primary particle size of the carbon black particles is preferably 10 to 100 nm, more preferably 15 to 70 nm, and still more preferably 20 to 50 nm. When the primary particle size of the carbon black particles is 10 nm or more, the particles are dispersed in the film, so that the color unevenness of the film is suppressed, the filter life in the melt extruder is increased, and sufficient productivity is achieved. Or can be obtained.
Moreover, the dispersion | variation in the light-shielding performance in a film width direction may be suppressed because the primary particle diameter of carbon black particle shall be 100 nm or less.

In addition, from the viewpoint of handleability and light shielding properties of the colored polyester film, it is important to include particles having an average particle size of 3.5 μm or more in addition to the colorant.
When the colored polyester film of the present invention contains particles having an average particle size of 3.5 μm or more, it can impart light scattering properties and film transportability by roughening the surface of the colored polyester film.
In the production of the colored polyester film, the influence of the wavelength dependency of the colorant itself is increased only with the colorant. Even if the content of the colorant is increased, it is difficult to maintain a light shielding property and an antireflection property at a high level in all inspection wavelength regions (400 nm to 800 nm). Therefore, by containing a colorant and particles having an average particle size of 3.5 μm or more in the colored polyester film, it is possible to maintain light shielding properties and antireflection properties in all inspection wavelength regions (400 nm to 800 nm). Become.

The type of the particle is not particularly limited as long as it does not impair the gist of the present invention. Specific examples include particles of silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide, and the like. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.
Among these, silica particles are more preferable because they can be used for general purposes.

  On the other hand, the shape of the particles is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

The lower limit of the average particle diameter of the particles is 3.5 μm or more, preferably 4 μm or more. When the average particle size is 3.5 μm or more, a sufficient light scattering effect is obtained in the visible light region, which contributes to light shielding properties. Further, the colored polyester film can have sufficient scratch resistance.
On the other hand, the upper limit of the average particle diameter of the particles is not particularly limited, but is preferably 20 μm or less, and more preferably 10 μm or less. When the average particle diameter is 20 μm or less, dropping of the particles is suppressed during conveyance of the colored polyester film.

  The content of the particles is preferably in the range of 0.01 to 10% by weight, more preferably 0.1 to 5% by weight. When the content of the particles is 0.01% by weight or more, sufficient light scattering properties and mechanical properties can be obtained. On the other hand, when it is 10% by weight or less, it is possible to reduce scratches on the film surface due to friction with the roll in the step of transporting the film by the roll-to-roll method.

  In addition to the particles, the colored polyester film may be added with a conventionally known antioxidant, antistatic agent, thermal stabilizer, lubricant, ultraviolet absorber, etc. as necessary, as long as the gist of the present invention is not impaired. Can do.

In the present invention, the transmission density of the colored polyester film needs to be 1.0 or more. The transmission density conforms to the ISO 5/2 method, and is calculated by the following equation using the light transmittance (%). When the transmission density is less than 1.0, the light shielding property is insufficient, and thus there is a possibility of causing an inspection failure in the inspection process.
Transmission density = log (100 / light transmittance)

  In the present invention, a roughened film can be obtained by containing particles having an average particle size of 3.5 μm or more. In order to achieve both light scattering properties and film transportability of the colored polyester film, the arithmetic average roughness (Ra) of the colored polyester film is preferably 80 nm or more, more preferably 90 nm or more, and even more preferably 100 nm or more. is there.

  When the arithmetic average roughness (Ra) of the colored polyester film is 80 nm or more, not only a sufficient light scattering property can be obtained, but also in the process of transporting the film by a roll-to-roll method, the friction between the roll and the film This is preferable because scratches are reduced on the film surface.

  As a standard of the light scattering property of the colored polyester film of the present invention, the absolute reflectance in the wavelength region of 400 nm to 800 nm is 6.0% or less, preferably 5.0% or less, more preferably 4.5%. It is as follows. By setting the absolute reflectance in the wavelength region to 6.0% or less, the influence of light reflection from the colored polyester film can be suppressed, the occurrence of defects in the inspection process can be suppressed, and it is also effective as a light shielding member. is there.

In order to increase the inspection accuracy in each wavelength region, the difference (ΔR) between the maximum and minimum absolute reflectances in the wavelength region of 400 nm to 800 nm is preferably 1.0% or less, 0.8 % Or less is more preferable, and 0.5% or less is more preferable.
The absolute reflectance and ΔR can be achieved by adjusting the type and content of the colorant, the average particle size and content of the particles, and the like.

  The thickness of the colored polyester film is not particularly limited as long as it can be formed as a film, but is preferably 9 μm to 250 μm, more preferably 12 μm to 100 μm, and still more preferably 25 μm to 75 μm for use. It is.

  Then, although the manufacture example of a colored polyester film is demonstrated concretely, it is not limited to the following manufacture examples at all.

The method for adding the colorant and the particles to the colored polyester film is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester, but it may be preferably at the stage of esterification or the stage after completion of the transesterification reaction.
Also, a method of blending the colorant dispersed in ethylene glycol or water with a vented kneading extruder and a slurry of the polyester and a polyester raw material, or the colorant dried using a kneading extruder And a method of blending the particles and the polyester raw material.

  A method of using the above-mentioned polyester raw material and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed.

Next, the obtained unstretched sheet is preferably stretched at least in a uniaxial direction, and more preferably stretched in a biaxial direction.
In the case of sequential biaxial stretching, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is preferably 70 to 120 ° C, more preferably 80 to 110 ° C, and the stretching ratio is preferably 2.5 to 7 times, more preferably 3.0 to 6 times. Next, the film is stretched in a direction orthogonal to the first-stage stretching direction. The stretching temperature is usually 70 to 170 ° C., and the stretching ratio is preferably 3.0 to 7 times, more preferably 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the biaxial stretching, a method of performing unidirectional stretching in two or more stages may be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  For the production of the colored polyester film, a simultaneous biaxial stretching method can also be adopted. In the simultaneous biaxial stretching method, the unstretched sheet is preferably stretched simultaneously in the machine direction (longitudinal direction) and in the width direction (transverse direction) in a state where the temperature is controlled preferably at 70 to 120 ° C., more preferably at 80 to 110 ° C. The stretching ratio is preferably 4 to 50 times, more preferably 7 to 35 times, and still more preferably 10 to 25 times as an area ratio. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a biaxially stretched film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  In addition, a coating layer such as a pressure-sensitive adhesive layer, a release layer, an antistatic layer, and an oligomer precipitation preventing layer may be provided on at least one surface of the colored polyester film as long as the gist of the present invention is not impaired.

One method for providing the coating layer is a so-called coating stretching method (inline coating) in which the film surface is treated during the stretching step of the colored polyester film. For example, in the sequential biaxial stretching, the first stage of stretching is completed, and the coating treatment can be performed before the second stage of stretching.
When a coating layer is provided on a colored polyester film by a coating stretching method, coating can be performed simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, which is suitable as a colored polyester film. A film can be manufactured.

  As a method of providing the coating layer on the colored polyester film, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, or the like can be used. Regarding the coating method, there is a description example in “Coating method bookstore Yuji Harasaki published in 1979”.

  The curing conditions for forming the coating layer on the colored polyester film are not particularly limited. When the coating layer is provided by off-line coating, it is preferably 120 to 200 ° C. for 1 minute to 10 minutes, more preferably 100. Heat treatment is preferably performed at ˜180 ° C. for 1 minute to 10 minutes. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and an energy source can be used as an energy source for hardening by active energy ray irradiation.

  In addition, you may perform surface treatment, such as a corona treatment and a plasma treatment, as needed for the colored polyester film before providing an application layer.

[Inspection support]
Subsequently, the inspection support will be described. The inspection support in the present invention refers to a laminate in which a pressure-sensitive adhesive layer is laminated on a colored polyester film.

  The said adhesive layer means the layer comprised from the material which has adhesiveness, and uses a conventionally well-known material, such as a silicone type adhesive and an acrylic adhesive, in the range which does not impair the main point in this invention. it can.

  The pressure-sensitive adhesive layer may be provided on a colored polyester film in the film production process such as the above-described coating stretching method (inline coating), and employs a so-called off-line coating that is applied outside the system on the produced film. Any method may be adopted.

  Moreover, in the range which does not impair the main point of this invention, you may provide coating layers, such as a mold release layer, an antistatic layer, and an oligomer precipitation prevention layer, in the test | inspection support body in the surface in which the adhesive layer is not provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Primary particle size of colorant A sample film piece was fixed and molded with an epoxy resin, cut with a microtome, and the cross section of the film was observed with a transmission electron microscope. The maximum diameter (a) of the colorant observed in the cross section of the film and the diameter (b) orthogonal thereto were measured, and the primary particle diameter was determined from the following formula. The same measurement was performed on 500 colorants extracted at random, and the arithmetic average was defined as the primary particle size of the colorant.
Primary particle size = (a + b) / 2

(4) Thickness measurement of colored polyester film The sample film was measured with a thickness meter (Mahr 1301, Millimar 1240, manufactured by Mahr).

(5) Arithmetic average roughness (Ra) measurement of colored polyester film Ra was measured according to the method of JIS-B-0601-1994 using a surface roughness measuring machine (SE3500, manufactured by Kosaka Laboratory). The cut-off value was measured as 80 μm.

(6) Absolute reflectance measurement of colored polyester film Using an ultraviolet-visible infrared spectrophotometer (manufactured by JASCO Corporation, V-670), the polarizer is N-polarized light, the incident angle is 5 °, the scanning speed is 1000 nm / min, and data The absolute reflectance was measured continuously in the wavelength region of 300 nm to 800 nm with the capture interval being 1.0 nm. Absolute reflectances at wavelengths of 400 nm, 500 nm, 600 nm, 700 nm, and 800 nm were extracted from the measurement results. Further, the maximum and minimum absolute reflectance values at wavelengths of 400 nm to 800 nm were extracted, and the difference between them was taken as ΔR.

(7) Transmission Density of Colored Polyester Film and Light-shielding Evaluation The transmission density of a single obtained film was measured using a portable black and white transmission densitometer (Ihara Electronics Co., Ltd., Ihac-T5). The measured value of the obtained transmission density was evaluated for light shielding properties according to the following evaluation criteria.
"Evaluation criteria"
A: Transmission density is 2.0 or more (practically preferred level)
B: Transmission density is 1.0 or more and less than 2.0 (practical level)
C: Transmission density less than 1.0 (practical level)

(8) Scratch resistance evaluation of colored polyester film A rubbing tester (manufactured by Ohira Rika Kogyo Co., Ltd.), the total weight of the arm to which a flat stainless steel (SUS) plate (50 mm × 70 mm) was attached was 725 g, the scanning speed was 6 m / min, The number of reciprocations was 10, and a flat SUS plate and a colored polyester film (200 mm × 100 mm) fixed on the operation plate side were rubbed together, and then scratches on the colored polyester film surface were evaluated. The scratch described here refers to a scratch that is so tight that a crease is formed in the film. The scratch resistance was evaluated according to the following evaluation criteria.
"Evaluation criteria"
A: There is no scratch at all. (Practically preferred level)
B: One or more scratches enter. (Practical difficulty level)

(9) Evaluation of inspection suitability A light source (tungsten bulb), C light source (light source equivalent to average daylight) as a light source, argon laser (Spectra Physic, wavelength: 514.5 nm), ruby laser (Apollo) as a laser source Manufactured, wavelength: 694 nm), YAG laser excitation dye laser (Continuum, variable wavelength range: 420 to 560 nm “THG excitation”), YAG laser excitation dye laser (550 to 740 nm “SHG excitation”), a total of six light sources, transmission A detector using a source lamp or laser (manufactured by Mec Co., Ltd., LSC-6000) was used to detect defects in the laminate in which a resin sheet was provided on the inspection support. Inspection suitability was evaluated according to the following evaluation criteria.
<Criteria>
A: All detectors can be inspected. (Practically preferred level)
B: Even one cannot be inspected. (Practical difficulty level)

(10) Comprehensive evaluation Based on the evaluation result in each item of a sample film, it evaluated by the following evaluation criteria.
"Evaluation criteria"
○: All of light shielding properties, scratch resistance, and inspection suitability are practically preferable or at a practical level.
X: Any one of light shielding properties, scratch resistance, and inspection suitability is difficult to use.

  The polyester used in Examples and Comparative Examples is as follows.

<Manufacture of polyester>
Production Example 1 (Polyethylene terephthalate A)
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol and 0.09 parts by weight of magnesium acetate tetrahydrate are placed in a reactor, heated to a temperature and distilled off of methanol to carry out a transesterification reaction. In short, the temperature was raised to 230 ° C., and the transesterification reaction was substantially completed. Next, 0.04 part by weight of ethylene glycol slurry of ethyl acid phosphate and 0.03 part by weight of antimony trioxide were added, and then the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. Was finally reduced to 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyethylene terephthalate A having an intrinsic viscosity of 0.65 dl / g.

Production Example 2 (Polyethylene terephthalate B)
80 parts by weight of polyethylene terephthalate A produced in Production Example 1 and 20 parts by weight of carbon black particles having a primary particle diameter of 20 nm were dry blended and extruded using a twin-screw kneading extruder to obtain polyethylene terephthalate B. The intrinsic viscosity of the obtained polyethylene terephthalate B was 0.58 dl / g.

Production Example 3 (Polyethylene terephthalate C)
Polyethylene terephthalate C ′ was obtained in the same manner as in Production Example 1, except that it took 4 hours from the start of the transesterification reaction and the temperature was raised to 240 ° C. 96.5 parts by weight of the polyethylene terephthalate C ′ and 3.5 parts by weight of silica particles having an average particle size of 4.1 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyethylene terephthalate C. The intrinsic viscosity of the obtained polyethylene terephthalate C was 0.70 dl / g.

Production Example 4 (Polyethylene terephthalate D)
98.75 parts by weight of polyethylene terephthalate A produced in Production Example 1 and 1.25 parts by weight of silica particles having an average particle diameter of 3.2 μm were dry blended and extruded using a twin-screw kneading extruder to obtain polyethylene terephthalate D. Obtained. The intrinsic viscosity of the obtained polyethylene terephthalate D was 0.64 dl / g.

Example 1
The raw materials in which the above polyethylene terephthalates A, B, and C are mixed at a ratio of 87% by weight, 5% by weight, and 8% by weight are melt extruded by a melt extruder, and the sheet is coextruded on a cooled casting drum to be cooled and solidified. Thus, a single-layer non-oriented sheet was obtained. Subsequently, the film was stretched 3.3 times at 86 ° C. in the machine direction (longitudinal direction), and further stretched 4.3 times at 115 ° C. in the direction perpendicular to the machine direction (lateral direction) through a preheating step in a tenter. After biaxial stretching, a heat treatment was performed at 235 ° C. for 3 seconds, followed by a 2.0% relaxation treatment in the width direction to obtain a colored polyester film having a thickness of 38 μm.
Next, after applying an offline pressure-sensitive adhesive layer comprising the following pressure-sensitive adhesive composition by a reverse gravure coating method so that the coating amount (after drying) is 25 g / m ² , and then drying at 100 ° C. for 5 minutes. An inspection support was obtained. The evaluation results are shown in Table 2 below.
<< Adhesive composition >>
A solution of an acrylic copolymer having a weight average molecular weight of 600,000 (polystyrene equivalent) by copolymerizing butyl acrylate (100 parts by weight, acrylic acid 6 parts by weight) in ethyl acetate by a conventional method (solid content 30% by weight) ) To 100 parts by weight (solid content) of an acrylic copolymer, N, N-dimethylaminoethyl acrylate, 0.2 parts by weight, and 6 parts by weight of Tetrad C (manufactured by Mitsubishi Gas Chemical), which is an epoxy-based crosslinking agent, are added. A pressure-sensitive adhesive composition was obtained.

(Examples 2-5, Comparative Examples 1-4)
A test support was obtained in the same manner as in Example 1 except that the raw material composition of the colored polyester film was changed as shown in Table 1. The evaluation results are shown in Table 2 below.

(Comparative Example 5)
A raw material in which polyethylene terephthalate A and D were mixed at a ratio of 86% by weight and 14% by weight was used as a raw material for the surface layer, and a raw material containing 100% by weight of polyethylene terephthalate A was used as a raw material for the intermediate layer. The sheets were melt-extruded by different melt extruders and co-extruded on a cooled casting drum and cooled and solidified to obtain a non-oriented sheet of two types and three layers (surface layer / intermediate layer / surface layer). Subsequently, the film was stretched 3.3 times at 86 ° C. in the machine direction (longitudinal direction), and further stretched 4.3 times at 115 ° C. in the direction perpendicular to the machine direction (lateral direction) through a preheating step in a tenter. After biaxial stretching, a heat treatment was performed at 235 ° C. for 3 seconds, followed by a 2.0% relaxation treatment in the width direction to obtain a colored polyester film having a thickness of 38 μm.
Next, the pressure-sensitive adhesive layer was laminated off-line in the same manner as in Example 1 to obtain an inspection support. The evaluation results are shown in Table 2 below.

  When the colored polyester film of the present invention is used for inspection of various members, it has a light shielding property and antireflection property at a high level, so that it is easy to inspect defects such as foreign matter inspection in an inspection process involving optical evaluation. , LCD backlight, organic EL, inorganic EL, etc., as well as inspection support when manufacturing various display optical members, and also suitable as a light-shielding member for optical devices such as cameras, video cameras, copying machines, developing machines, etc. be able to.

Claims (7)

  A resin composition comprising polyester, a colorant, and particles having an average particle diameter of 3.5 μm or more, having a transmission density of 1.0 or more and an absolute reflectance of 6.0% or less in a wavelength region of 400 nm to 800 nm. A colored polyester film characterized by being.   The colored polyester film according to claim 1, wherein the colorant is carbon black particles.   The colored polyester film according to claim 1 or 2, wherein the content of the colorant is 0.01 to 10% by weight.   The colored polyester film according to any one of claims 1 to 3, wherein an arithmetic average roughness (Ra) of at least one surface is 80 nm or more.   The colored polyester film according to any one of claims 1 to 4, wherein a difference (ΔR) between a maximum value and a minimum value of absolute reflectance in a wavelength region of 400 nm to 800 nm is 1.0% or less.   The test support body which laminated | stacked the colored polyester film and adhesive layer in any one of Claims 1-5.   The light-shielding member using the colored polyester film in any one of Claims 1-5.