WO2017142287A1 - Shielding polyester film - Google Patents

Abstract

An embodiment relates to a polyester film having a high light-shielding effect by using light-absorbing particles and light-diffusing particles, wherein the polyester film has an excellent light-shielding effect since three or more layers of the polyester film are formed such that the light of a light source is firstly blocked by a first light-shielding layer, and the remaining light is scattered or reflected by a light-scattering layer and then absorbed by a second light-shielding layer, and thus the polyester film can be used in various display fields requiring high light-shielding properties.

Description

Polyester shielding film

The embodiment relates to a polyester film having a high light shielding effect by utilizing light absorbing particles and light scattering particles.

In general, a flat panel display (FPD) is classified into a light emitting type and a light receiving type. An example of a light-receiving flat panel display device is a liquid crystal display (LCD), which does not emit light by itself and forms a liquid crystal image, and light is incident from outside to form a liquid crystal image. can do. Accordingly, a liquid crystal display device which does not emit light by itself includes a backlight unit on the back side that evenly shines the display image so that the display image is visible, and the backlight unit mostly includes a light emitting diode (LED) as a light source.

The LCD transmits an image by converting an input electric signal into visual information by using a characteristic in which light transmittance of a liquid crystal changes according to an applied voltage. That is, a typical LCD is composed of two substrates provided with transparent electrodes and liquid crystal injected between the two substrates. Electricity is applied to the liquid crystals by applying different voltages to the two substrates, and the light transmittance is changed as the arrangement of the liquid crystal molecules is changed.

In order to prevent the leakage of light from LEDs, which are light sources in LCDs used in mobile phones or TVs, light black is usually applied to a transparent polyethylene terephthalate (PET) film several times (for example, six times). Degree) coating was used as a shielding film to block light. However, the multiple coating of carbon black as described above causes the blocking property of the film and has a problem that it is not economical.

On the other hand, Korean Patent No. 10-0367472 discloses a resin composition for black matrices comprising two kinds of binder resins, multifunctional monomers, carbon black, photoinitiators, silicone additives and organic solvents as main components. However, in the case of the film produced by adding the carbon black to the inside, when an excessive amount of carbon black is added to realize the shielding property, film forming becomes impossible because it affects the film forming property, and it does not affect the film forming property. When carbon black is added, there is a problem that it is difficult to realize the shielding of the film.

Therefore, the objective of the Example is to provide the polyester shielding film which has the outstanding film forming property and shielding property.

In order to achieve the above object, one embodiment is a laminated film including a three-layer structure of the first shielding layer / light scattering layer / second shielding layer,

The first shielding layer and the second shielding layer each include a polyester resin and light absorbing particles,

The light scattering layer provides a polyester shielding film comprising a polyester resin and light scattering particles.

Another embodiment includes a first shielding layer; A light scattering layer disposed on the first shielding layer; And a second shielding layer disposed on the light scattering layer, wherein the light scattering layer changes a path of light incident from the first shielding layer or the second shielding layer by light scattering. do.

According to another embodiment of the present disclosure, a method of manufacturing a shielding film may include a first shielding layer composition including a first resin and first light absorbing particles; A light scattering layer composition comprising a second resin and light scattering particles; And coextruding a second shielding layer composition comprising the third resin and the second light absorbing particles to prepare a sheet in which the second shielding layer, the light scattering layer, and the first shielding layer are sequentially stacked.

The polyester shielding film of the embodiment has no problem in film forming property, and is formed in three or more layers so that the light of the light source is first blocked by the first shielding layer, and the remaining light is reflected or scattered by the light scattering layer and then the second shielding. It is absorbed by the layer and shows a high light shielding effect. In addition, the shielding film of the embodiment is economical to exhibit an excellent light shielding effect while using a smaller amount of carbon black than the polyester film prepared by conventional carbon black coating.

1 is a cross-sectional view showing a shielding film according to an embodiment (10: shielding film, 11: first shielding layer, 12: light scattering layer, 13: second shielding layer).

2 is a cross-sectional view of a shielding film according to an embodiment (111 and 131: light absorbing particles and 121: light scattering particles).

3 and 4 show results of dark room LED transmission of Experimental Example 1. FIG.

Polyester shielding film of the embodiment is a laminated film comprising a three-layer structure of the first shielding layer / light scattering layer / second shielding layer, wherein the first shielding layer and the second shielding layer are respectively a polyester resin and light absorbing particles It includes, the light scattering layer comprises a polyester resin and light scattering particles.

1 and 2, the shielding film 10 has a three-layer structure of the first shielding layer 11 / light scattering layer 12 / the second shielding layer 13, specifically, the 3 The layer film may be coextruded. In addition, the first shielding layer 11 and the second shielding layer 13 include light absorbing particles 111 and 131, respectively, and the light scattering layer 12 includes light scattering particles 121.

The first shielding layer and the second shielding layer each include a polyester resin and light absorbing particles. In detail, each of the first shielding layer and the second shielding layer may include a polyester resin and light absorbing particles 111 and 131 in an amount of 95 wt% or less and 5 wt% or more, and the polyester shielding film may include a film total weight. The light absorbing particles may be included in an amount of 3% by weight or more based on the amount. In more detail, each of the first shielding layer and the second shielding layer includes polyester resin and light absorbing particles in an amount of 85 to 95% by weight and 5 to 15% by weight, and the polyester shielding film is based on the total weight of the film. As such, the light absorbing particles may be included in an amount of 3 to 10% by weight. In more detail, each of the first shielding layer and the second shielding layer includes a polyester resin and light absorbing particles in an amount of 90 to 95% by weight and 5 to 10% by weight, and the polyester shielding film is based on the total weight of the film. As such, the light absorbing particles may be included in an amount of 5 to 8% by weight. When the polyester resin and the light absorbing particles are included in the above range, it may have an excellent light shielding effect and high film forming properties compared to the carbon black used.

Each of the first shielding layer and the second shielding layer includes a polyester resin. In more detail, each of the first shielding layer and the second shielding layer includes at least one polyester resin. The polyester resin may be a homopolymerized polyester or a copolyester.

The polyester resin includes a diol repeating unit and a dicarboxylic acid repeating unit. In more detail, the polyester resin may be composed of a diol repeating unit and a dicarboxylic acid repeating unit.

The polyester resin may be formed by polymerization after the diol repeat unit and the dicarboxylic acid repeat unit are transesterified.

Specific examples of the diol repeating unit include ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2, 3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-butyl-2-ethyl-1 , 3-propanediol, 2,2-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,1-dimethyl -1,5-pentanediol, spiroglycol (3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane), Diethylene glycol (2- (2-hydroxyethoxy) ethan-1-ol) and mixtures thereof. In more detail, the diol repeating unit may include ethylene glycol.

Specific examples of the dicarboxylic acid repeating unit include aromatic dicarboxylic acids such as terephthalic acid, dimethyl terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and orthophthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid; Alicyclic dicarboxylic acid; Ester esters thereof; And mixtures thereof. In more detail, the dicarboxylic acid repeating unit may include terephthalic acid.

The intrinsic viscosity (IV) of the polyester resin may be 0.35 to 1.50 dl / g, more specifically 0.40 to 1.50 dl / g.

The light absorbing particles may be colored. In detail, the light absorbing particles may be at least one selected from the group consisting of carbon black, carbon nanotubes (CNT), and graphene. In more detail, the light absorbing particles may be carbon black.

The light absorbing particles may have an average particle diameter of 5 to 300 nm. In more detail, the light absorbing particles may have an average particle diameter of 10 to 100 nm.

The first shielding layer and the second shielding layer may be the same or different.

The light scattering layer 12 includes a polyester resin and light scattering particles 121. In detail, the light scattering layer includes polyester resin and light scattering particles in an amount of 95 wt% or less and 5 wt% or more, and the polyester shielding film contains an amount of light scattering particles in an amount of 1 wt% or more based on the total weight of the film. It may include. More specifically, the light scattering layer comprises a polyester resin and light scattering particles in an amount of 80 to 95% by weight and 5 to 20% by weight, the polyester shielding film is based on the total weight of the film 1 To 10% by weight. More specifically, the light scattering layer comprises a polyester resin and the light scattering particles in an amount of 85 to 90% by weight and 10 to 15% by weight, the polyester shielding film is based on the total weight of the film 2 light scattering particles To 7% by weight. When including the copolyester resin and the light scattering particles in the above range, it is possible to maximize the light reflection and scattering effect in the state of film fairness.

In addition, the light scattering layer may be a light reflection and scattering layer that can reflect and scatter incident light.

As shown in FIG. 2, the light scattering layer may change the path of the light incident from the first or second shielding layer laterally, and thus, the light scattering layer may have a higher intensity than that of the light incident from the first or second shielding layer. The light passing through the light scattering layer has a longer path. Accordingly, the light absorption efficiency in the first or second shielding layer is maximized, and the shielding property of the film can be very high.

The polyester resin is as defined in the first shielding layer and the second shielding layer.

The light scattering particles reflect and scatter incident light, whereby the light scattering particles change the path of light incident on the particle. In detail, the light scattering particles may be light reflection and scattering particles. In addition, pores may be formed between the light scattering particles and the polyester resin. Since the pores may perform a function of reflecting and scattering incident light, the pores may also play a role similar to that of light scattering particles.

The light scattering particles may be at least one selected from the group consisting of titanium dioxide (TiO ₂ ), barium (Ba), silicon dioxide (SiO ₂ ), calcium carbonate (CaCO ₃ ), and white earth (kaolin). In more detail, the light absorbing particles may be titanium dioxide (TiO ₂ ).

The titanium dioxide may be in crystalline form of anatase or rutile, and any form may be used. In more detail, the titanium dioxide may be rutile type. The rutile type has a higher absorbance property for light relative to the anatase type, and thus has a good absorbing ability against ultraviolet rays, and thus has excellent UV blocking effect, and shows high stability against UV rays (UV reliability). It doesn't work. In addition, since the rutile type has a higher refractive index of 2.7 (anatase type refractive index: 2.5) and a significantly higher dielectric constant of 114 (anatase type dielectric constant: 31) than the anatase type, it can be used more preferably.

The light scattering particles may have an average particle diameter of 100 to 1,000 nm. In more detail, the light scattering particles may have an average particle diameter of 200 to 800 nm.

The polyester shielding film may have a first shielding layer, a light scattering layer, and a second shielding layer in a thickness ratio of 0.5 to 10: 1: 0.5 to 10. In more detail, the polyester shielding film may have a first shielding layer, a light scattering layer, and a second shielding layer in a thickness ratio of 0.5 to 3: 1: 0.5 to 3.

The polyester shielding film may have a thickness of 10 to 30 ㎛. In more detail, the polyester shielding film may have a thickness of 15 to 25 ㎛.

Examples of the polyester shielding film may include polymerization catalysts, dispersants, antiblocking agents, antistatic agents, antistatic agents, antioxidants, thermal stabilizers, and sunscreen agents, which are well known in the art, within the range of not impairing the effects of the present invention. It may be, for example, added in the range of 0.001 to 10.0% by weight relative to the total weight of the shielding film.

The polyester shielding film of the embodiment may further have a multilayer structure of three or more layers, further including an additional shielding layer and a scattering layer in addition to the first shielding layer, the light scattering layer, and the second shielding layer.

Polyester shielding film according to the embodiment may be prepared by the following process.

(1) Resin containing the polyester resin and light scattering particle which comprise the resin compositions 1 and 2 containing the polyester resin and light-absorbing particle which comprise each of a 1st shielding layer and a 2nd shielding layer, and light-scattering layer Providing composition 3;

(2) coextruding the resin compositions to produce an unstretched sheet; And

(3) can be produced by a manufacturing method, including the step of stretching the unstretched sheet.

First, the polyester resin may be prepared by an esterification reaction of a diol repeating unit with a dicarboxylic acid repeating unit and a solid phase polymerization process according to a conventional method.

In addition, each of the first shielding layer and the second shielding layer may be composed of resin compositions 1 and 2 prepared by a process of mixing the polyester resin prepared as described above and the light absorbing particles according to a conventional method. . The said resin compositions 1 and 2 may be the same and may differ.

Furthermore, the light scattering layer may be composed of a resin composition 3 prepared by a process of mixing the polyester resin prepared as described above and the light scattering particles according to a conventional method.

Next, the resin compositions 1, 2, and 3 were coextruded (melt-extruded) into different layers according to a conventional method, and then cooled, and laminated in the order of the first shielding layer / light scattering layer / second shielding layer. The unstretched sheet of a three layer structure is manufactured.

Specifically, the melt extrusion may co-extrude the resin compositions 1, 2, and 3 into different layers, respectively, at a temperature of Tm + 30 ° C. to Tm + 80 ° C. Moreover, it is preferable that the said cooling is made at the temperature of 30 degrees C or less, for example, 15-30 degreeC.

Thereafter, the unstretched sheet is stretched and heat-set in one or both directions of a first direction, for example, a longitudinal direction (machine direction) and a second direction perpendicular to the first direction, for example, a width direction (tenter direction). The desired polyester shielding film can be manufactured.

Specifically, the unstretched sheet may be uniaxially or biaxially stretched.

The unstretched sheet may be stretched in the first direction, for example, 1.0 to 4.5 times in the longitudinal direction, and in the second direction, for example 1.0 to 5.0 times in the width direction. In more detail, the unstretched sheet may be stretched in a first direction, for example, 1.0 to 3.5 times in the longitudinal direction, and in a second direction, for example 3.0 to 4.5 times in the width direction.

The stretching temperature may be Tg + 5 ℃ to Tg + 80 ℃, in order to improve the brittleness of the film in more detail, the stretching temperature range may be Tg + 10 ℃ to Tg + 50 ℃. Tg is the glass transition temperature of the polyester resin.

After starting the heat setting, the film is relaxed in the longitudinal direction and / or the width direction, and the stretched sheet may be heat set at a temperature of 60 to 240 ° C., more specifically, 65 to 120 ° C.

The polyester shielding film of the embodiment thus prepared is easy to form a film, consisting of a three-layer structure, the light of the light source is first blocked by the first shielding layer, the remaining light is scattered or reflected by the light scattering layer 2 is absorbed by the shielding layer and exhibits high light shielding effect. In addition, the shielding film is economical because it exhibits an excellent light shielding effect while using a smaller amount of carbon black than the polyester film prepared by conventional carbon black coating.

One embodiment includes a first shielding layer; A light scattering layer disposed on the first shielding layer; And a second shielding layer disposed on the light scattering layer, wherein the light scattering layer changes a path of light incident from the first shielding layer or the second shielding layer by light scattering. do.

The first shielding layer and the second shielding layer may each include a first resin and light absorbing particles. In detail, the first resin may be a polyester resin. In addition, the light absorbing particles may be colored.

The type and content of the polyester resin and the light absorbing particles are as defined in the polyester shielding film.

The light scattering layer may include a second resin and light scattering particles. In detail, the difference in refractive index between the second resin and the light scattering particles may be 0.05 or more. In more detail, the difference in refractive index between the second resin and the light scattering particles may be 0.05 to 8.

The second resin may be a polyester resin.

The type and content of the polyester resin and the light scattering particles are as defined in the polyester shielding film.

The shielding film may have an optical density of 5.0 or more. In detail, the shielding film may have an optical density of 5.0 to 20.

The shielding film according to the embodiment may be prepared by the following process.

A first shielding layer composition comprising a first resin and first light absorbing particles;

A light scattering layer composition comprising a second resin and light scattering particles; And

Coextruding a second shielding layer composition comprising a third resin and second light absorbing particles to prepare a sheet in which a second shielding layer, a light scattering layer, and a first shielding layer are sequentially stacked; It can be manufactured by the manufacturing method.

Each of the first resin, the second resin, and the third resin may be a polyester resin. The polyester resin is as defined in the polyester shielding film.

The type and content of the first light absorbing particles and the second light absorbing particles are as defined in the polyester shielding film.

In addition, the coextruded sheet may be cooled to prepare an unstretched sheet. In detail, the coextrusion (melt extrusion) and cooling are as defined in the polyester shielding film.

The manufacturing method may further include stretching the unstretched sheet.

The stretching is as defined in the polyester shielding film.

After the stretching, the stretched film may be heat set. The heat setting is as defined in the polyester shielding film.

The shielding film prepared as described above has a total thickness of 10 to 30 µm, an optical density of 5.0 or more, and a thickness ratio of the first shielding layer, the light scattering layer, and the second shielding layer to 0.5 to 10: 1 0.5 to 10. Can be.

The shielding film of the embodiment thus prepared is easy to form a film, consisting of a three-layer structure, the light of the light source is first blocked by the first shielding layer, the remaining light is scattered or reflected by the light scattering layer and the second shielding It is absorbed by the layer and shows a high light shielding effect. In addition, the shielding film is economical because it exhibits an excellent light shielding effect while using a smaller amount of carbon black than the polyester film prepared by conventional carbon black coating.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

EXAMPLE

Preparation Example 1 Preparation of Shielding Layer Resin Composition

After raising the esterification reaction tube to 200 degreeC, 100 mol% of ethylene glycol and 100 mol% of terephthalic acid were added, and 0.017 weight part of manganese acetate was added as a catalyst based on 100 weight part of these raw materials, and it stirred. Then, the pressure was elevated to carry out a pressure esterification reaction at a gauge pressure of 0.34 MPa and 240 ° C., and then the esterification tube was returned to normal pressure, and then 0.014 parts by weight of phosphoric acid was added. Then, it heated up at 260 degreeC over 15 minutes, and 0.012 weight part of trimethyl phosphate was added as a stabilizer. Subsequently, after 15 minutes, the dispersion treatment was performed with a high pressure disperser. After 15 minutes, the obtained esterification product was transferred to a polycondensation reaction tube, and the polycondensation reaction was carried out at 280 ° C. under reduced pressure for 1 hour to obtain a polyester resin ( Inherent viscosity (IV viscosity) 0.61) of 3,000 cPs was obtained.

After completion of the polycondensation reaction, 8 wt% of carbon black (manufacturer: DIC, product name: KL7886) having an average particle diameter of 20 nm was added to 92 wt% of the polyester resin and mixed to prepare a shielding layer resin. Thereafter, a 95% cut size was filtered using a Naslon filter having a size of 5 μm, extruded into a strand shape from the nozzle, and cooled and solidified by using a cooling water subjected to a filtration treatment (pore size: 1 μm or less) beforehand to form a pellet By cutting, a shielding layer resin chip was produced.

Preparation Example 2 Preparation of Light Scattering Layer Resin Composition

Light scattering layer resin was prepared by adding 15 wt% of rutile titanium oxide (manufacturer: Dupont, product name: R104) having an average particle diameter of 300 nm to 85 wt% of the polyester resin prepared in the same manner as in Preparation Example 1, and mixing. Thereafter, the resultant was extruded into a strand shape, cooled and solidified using cooling water subjected to filtration treatment (pore size: 1 μm or less) in advance, and cut into pellets to form a light scattering layer resin chip.

Example 1.

The resin chips were melt coextruded through an extruder at 275 ° C. such that the shielding layer resin prepared in Preparation Example 1 constitutes the upper and lower surface layers, and the light scattering layer resin prepared in Preparation Example 2 is located between the surface layers. Then, it cooled on the casting roll of 20 degreeC, and produced the unstretched sheet. The unstretched sheet was stretched 4.0 times in the width direction at 75 ° C., heat-treated (heat-fixed) at 70 ° C. for 10 seconds, and then cooled to cool a three-layer polyester shielding film having a thickness of 20 μm (first shielding layer: light scattering layer: A thickness ratio of the second shielding layer = 1: 1: 1) was prepared.

Examples 2 to 13 and Comparative Example 1.

The polyester was prepared in the same manner as in Example 1, except that the carbon black content, the titanium oxide content, the thickness ratio of the shielding layer and the light scattering layer, and / or the thickness of the shielding film were changed as described in Table 2 below. A shielding film was prepared.

Comparative Example 2.

The shielding layer resin chip which mixed 5 weight% of carbon black with the polyester resin of the said manufacture example 1 was melt-coextruded through the extruder of 275 degreeC, and cooled by the casting roll of 20 degreeC, and the unstretched sheet was produced. . The unstretched sheet was stretched 4.0 times in the width direction at 75 ° C., heat-treated (heat-fixed) at 70 ° C. for 10 seconds, and cooled to prepare a monolayer polyester film having a thickness of 16 μm.

Comparative Example 3.

A single-layer polyester film having a thickness of 20 μm was manufactured in the same manner as in Comparative Example 2, except that a shielding layer resin chip containing 8% by weight of carbon black was used.

Comparative Example 4.

A single-layer polyester film was prepared in the same manner as in Comparative Example 3, except that a light scattering layer resin chip in which 15 wt% of titanium oxide was mixed with the polyester resin of Preparation Example 2 was used instead of the shielding layer resin chip. .

Experimental Example 1. Darkroom LED transmission measurement, darkroom luminance and color measurement

Films of Examples 1 to 4, 6 to 10, and Comparative Example 2 were closely adhered to a 0.5 Watt (W) LED light source in a dark room having luminous intensity of 1 Lux or less, and the degree of light transmission was photographed. The results are shown in FIGS. 3 and 4.

3 and 4, compared with the film of Comparative Example 2, the films of Examples 1 to 4 and 6 to 10 were excellent in shielding effect. In particular, the films of Examples 1, 3, 7, 9 and 10 showed high shielding properties.

In addition, in the dark room as described above, the film of Examples 1 to 4 and 6 to 10, and Comparative Example 2 was in close contact with the LED light source of 100 watts (W) to measure the brightness and color. The results are shown in Table 1 below.

Specifically, luminance and color were measured by closely contacting the films of Examples 1 to 4 and 6 to 10, and Comparative Example 2 with CS-2000, a high precision luminance measurement window of Konica Minolta Co., Ltd. using a 100 Watt (W) LED light source in a dark room. It was. The unit of each luminance is candela / square meter (Cd / m 2), and the color value is defined as CIE xy, which is a standard color coordinate.

Furthermore, the optical density of the film was calculated from the luminance of Examples 6 to 10 measured as described above.

	Luminance (Lv) (Cd / ㎡)	x	y	Optical density
Comparative Example 2 (Carbon Black 5 wt%)	0.5307	0.5517	0.4188	-
Example 1 (8 wt% carbon black)	0.0023	0.5070	0.3379	-
Example 2 (8% by weight of carbon black)	0.0266	0.5895	0.3905	-
Example 3 (10 wt% carbon black)	0.0021	0.5151	0.3305	-
Example 4 (10 wt% carbon black)	0.0146	0.5915	0.3799	-
Example 6 (7 wt% carbon black)	0.0266	0.589	0.391	6.0
Example 7 (7 wt% carbon black)	0.0023	0.506	0.335	7.1
Example 8 (7 wt% carbon black)	0.0146	0.591	0.380	6.2
Example 9 (7.6 weight% carbon black)	0.0020	0.516	0.324	7.1
Example 10 (7.6 weight% carbon black)	0.0008	0.348	0.261	7.5

As shown in Table 1, the films of Examples 1 to 4 and 6 to 10 showed significantly lower luminance as compared to the film of Comparative Example 2. In particular, the films of Examples 1, 3, 7, 9 and 10 showed exceptionally low brightness.

Experimental Example 2. Evaluation of Shielding

The degree of light transmission was determined by bringing the films of Examples 1 to 13 and Comparative Examples 1 to 4 into close contact with a 0.5 watt (W) LED light source in a dark room having luminous intensity of 1 Lux or less. Tables 2 and 3 below.

	Configuration				Content by weight of film (% by weight)		Thickness ratio			Total thickness of film	Shielding characteristic
	Shielding layer		Light scattering layer				1st shield layer	Light scattering layer	2nd shield layer
	ingredient	Content (% by weight)	ingredient	Content (% by weight)	Carbon black	TiO 2
Example 1	Carbon black	8	TiO 2 (Rutile)	15	5.3	5	One	One	One	20 ㎛	◎
Example 2	Carbon black	8	TiO 2 (Rutile)	15	5.3	5	One	One	One	15 μm	○
Example 3	Carbon black	10	TiO 2 (Rutile)	15	5.7	4.3	1.25	One	1.25	20 ㎛	◎
Example 4	Carbon black	10	TiO 2 (Rutile)	15	5.7	4.3	1.25	One	1.25	15 μm	◎
Example 5	Carbon black	10	TiO 2 (Rutile)	20	5.7	5.7	1.25	One	1.25	15 μm	◎
Example 11	Carbon black	4	TiO 2 (Rutile)	10	2.7	3.3	One	One	One	20 ㎛	△
Example 12	Carbon black	8	TiO 2 (Rutile)	15	2.7	10	0.5	2	0.5	20 ㎛	X
Example 13	Carbon black	5	TiO 2 (Anatase)	15	3.3	5	One	One	One	20 ㎛	△
Comparative Example 1	TiO 2 (Rutile)	15	Carbon black	8	2.7	10	One	One	One	20 ㎛	X
Comparative Example 2	Monolayer, Carbon Black 5 wt%									16 μm	X
Comparative Example 3	Monolayer, Carbon Black 8 wt%									20 ㎛	X
Comparative Example 4	Monolayer, TiO 2 15 wt%									20 ㎛	X

	Configuration				Thickness ratio			Total thickness of film	Shielding characteristic
	Shielding layer		Light scattering layer		1st shield layer	Light scattering layer	2nd shield layer
	ingredient	Content (% by weight)	ingredient	Content (% by weight)
Example 6	Carbon black	7	TiO 2 (Rutile)	13	One	One	One	15 μm	◎
Example 7	Carbon black	7	TiO 2 (Rutile)	13	One	One	One	20 ㎛	◎
Example 8	Carbon black	7	TiO 2 (Rutile)	13	1.3	One	1.3	15 μm	◎
Example 9	Carbon black	7.6	TiO 2 (Rutile)	13	1.3	One	1.3	15 μm	◎
Example 10	Carbon black	7.6	TiO 2 (Rutile)	17	One	One	One	20 ㎛	◎

◎ of the shielding characteristics are 80 to 100% shielding of the LED light source, ○ is 60 to 80% shielding of the LED light source, △ is 40 to 60% shielding of the LED light source and X is 40% shielding of the LED light source.

As shown in Tables 2 and 3 and FIGS. 3 and 4, the film of the example showed an excellent light shielding effect, but Comparative Example 1 using the resin of the shielding layer and the resin of the light scattering layer of the present example was light shielding effect. Was significantly lower. Moreover, it was confirmed that the film of Comparative Examples 2-4 using the polyester resin containing carbon black or titanium oxide as a single layer is low in light shielding effect. In particular, comparing the film of Example 1 with the film of Comparative Example 3 containing 1.5 times of carbon black, the light shielding effect of the film of Example 1 was excellent.

Claims (20)

1. A laminated film comprising a three-layer structure of the first shielding layer / light scattering layer / second shielding layer,

   The first shielding layer and the second shielding layer each include a polyester resin and light absorbing particles,

   The polyester shielding film in which the said light scattering layer contains a polyester resin and light scattering particle | grains.
2. The method of claim 1,

   The light-shielding particle is at least one member selected from the group consisting of carbon black, carbon nanotubes (CNT) and graphene (graphene), polyester shielding film.
3. The method of claim 1,

   Polyester shielding film, wherein the light absorbing particles have an average particle diameter of 5 to 300 nm.
4. The method of claim 1,

   Each of the first shielding layer and the second shielding layer comprises polyester resin and light absorbing particles in an amount of 95 wt% or less and 5 wt% or more,

   Wherein the polyester shielding film comprises light absorbing particles in an amount of at least 3% by weight based on the total weight of the film.
5. The method of claim 1,

   The light-scattering particles are at least one member selected from the group consisting of titanium dioxide (TiO ₂ ), barium (Ba), silicon dioxide (SiO ₂ ), calcium carbonate (CaCO ₃ ) and white earth (kaolin).
6. The method of claim 1,

   Polyester shielding film, wherein the light scattering particles have an average particle diameter of 100 to 1,000 nm.
7. The method of claim 1,

   The light scattering layer comprises polyester resin and light scattering particles in an amount of 95% by weight or less and 5% by weight or more,

   Wherein the polyester shielding film comprises light scattering particles in an amount of at least 1% by weight based on the total weight of the film.
8. The method of claim 1,

   The said polyester shielding film has a 1st shielding layer, a light scattering layer, and a 2nd shielding layer in thickness ratio of 0.5-10: 1: 0.5-10, The polyester shielding film.
9. The method of claim 1,

   A polyester shielding film, wherein the polyester shielding film has a thickness of 10 to 30 ㎛.
10. The method of claim 1,

    3 layer structure of the said 1st shielding layer / light-scattering layer / 2nd shielding layer is the coextrusion, The polyester shielding film.
11. The method of claim 1,

    And the polyester shielding film does not transmit light when measured with respect to a 0.5W light source in a dark room having an illuminance of 1 Lux or less.
12. A first shielding layer;

    A light scattering layer disposed on the first shielding layer; And

    A second shielding layer disposed on the light scattering layer,

    A shielding film, wherein the light scattering layer changes the path of light incident from the first shielding layer or the second shielding layer by light scattering.
13. The method of claim 12,

    The first shielding layer and the second shielding layer each include a first resin and light absorbing particles,

    The said light scattering layer contains a 2nd resin and light scattering particle | grains.
14. The method of claim 13,

    The said 1st resin and the 2nd resin are polyester films, respectively.
15. The method of claim 13,

    The shielding film whose difference in refractive index between the said 2nd resin and light scattering particle is 0.05 or more.
16. The method of claim 15,

    A shielding film, wherein said light absorbing particles are colored.
17. The method of claim 16,

    The shielding film has an optical density of 5.0 or more.
18. A first shielding layer composition comprising a first resin and first light absorbing particles;

    A light scattering layer composition comprising a second resin and light scattering particles; And

    Coextruding a second shielding layer composition comprising a third resin and second light absorbing particles to prepare a sheet in which a second shielding layer, a light scattering layer, and a first shielding layer are sequentially stacked; Manufacturing method.
19. The method of claim 18,

    The first resin, the second resin and the third resin are each a polyester resin,

    Further comprising the step of stretching the sheet, the manufacturing method of the shielding film.
20. The method of claim 19,

    The total thickness of the prepared shielding film is 10 to 30 ㎛,

    The thickness ratio of the first shielding layer, the light scattering layer and the second shielding layer is 0.5 to 10: 1: 0.5 to 10,

    The shielding film whose optical density of the produced shielding film is 5.0 or more.

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