KR100252036B1 - Three-layered polymer film - Google Patents

Abstract

PURPOSE: A three-layered polymer film and its preparation method are provided, to improve the embossing reproducibility, the heat stability and the mechanical properties and to prevent the HCl gas from being generated in firing. CONSTITUTION: The three-layered polymer film comprises a first layer which is made by diffusing 5-30 wt% of a polyolefin resin, 0.5-20 wt% of a compatibilizer and 0.5-30 wt% of a lubricant into a polyester resin with the limiting index of 0.5-0.7 dl/g which is selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate) and poly(butylene naphthalate) and comprises 80 wt% of poly(ethylene terephthalate) or more, a second layer which is made by diffusing 5-40 wt% of a flame retardant material into a polyester resin with the limiting index of 0.5-0.7 dl/g which is selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate) and poly(butylene naphthalate) and comprises 80 wt% of poly(ethylene terephthalate) or more, and is formed on any one side of the first layer; and a third layer which is made by diffusing 0.01-15 wt% of particles with the mean size of 0.1-10 micrometers which is selected from TiO2, CaCO3, BaSO4, silica, kaolin, talc and zeolite into a polyester resin with the limiting index of 0.5-0.7 dl/g which is selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate) and poly(butylene naphthalate) and comprises 80 wt% of poly(ethylene terephthalate) or more, and is formed on the other side of the first layer.

Description

3-layer polymer film

The present invention relates to a three-layer polymer film, and more specifically, to a three-layer polymer film having excellent mechanical strength and thermal stability without generating harmful gases such as hydrogen chloride when burning, unlike a conventional cosmetic material based on polyvinyl chloride. It is about.

Cosmetic materials refer to the interior and exterior of the building, printed decorative paper, cardboard. Conventionally, in order to prevent the propagation of the flame in the case of fire, a flame retardant paper or the like is coated with polyvinyl chloride (hereinafter referred to as PVC) on it, and then embossed or the like is mainly used. However, due to environmental problems due to hydrogen chloride generated during fire or incineration waste, acrylic resins or ethylene-vinyl copolymer resins have recently been used. However, the use of such a resin increases the manufacturing cost and there is a problem that the mechanical strength, thermal stability, and the reproducibility of embossing is lowered compared to the case of using PVC.

Accordingly, the technical problem to be achieved by the present invention is to provide a three-layer polymer film that can be used as a cosmetic material having excellent mechanical strength and thermal stability, does not generate hydrogen chloride during combustion, and has excellent emboss reproducibility due to its excellent weight and buffering properties. .

In order to achieve the above technical problem, the present invention is at least any one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate content of polyethylene terephthalate is 80% by weight or more and 5 to 30% by weight of a polyolefin resin in a polyester resin having an intrinsic viscosity of 0.5 to 0.7 dl / g, 0.5 to 20% by weight of a compatibilizer for improving compatibility between the polyester resin and the polyolefin resin, And a porous first layer made by dispersing 0.5-30% by weight of an organic lubricant. At least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate and having a content of polyethylene terephthalate of 80% by weight or more and an intrinsic viscosity of 0.5 to 0.7 dl / g A second layer formed by dispersing 5 to 40% by weight of a flame retardant in the ester resin and laminated on any one surface of the porous first layer; And at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, wherein the content of polyethylene terephthalate is 80% by weight or more and the ultimate viscosity is 0.5 to 0.7 dl / g. At least one selected from the group consisting of titanium dioxide, calcium carbonate, barium sulfate, silica, kaolin, talc and zeolite in a polyester resin is made by dispersing 0.01 to 15% by weight of fine particles having an average particle diameter of 0.1 to 10 μm. It provides a three-layer polymer film comprising a third layer laminated on any one surface of the porous first layer.

In the present invention, the thickness of the porous first layer is 50 to 80% of the total thickness of the three-layer polymer film, the thickness of the second layer is preferably 15% or less of the total thickness of the three-layer polymer film.

In the present invention, the density of the three-layer polymer film is preferably 0.80 to 1.10 g / cm ³ .

In the present invention, the flame retardant is preferably phosphinic acid.

In the present invention, the polyolefin-based resin is polymerized from at least one monomer selected from the group consisting of ethylene, propylene, butene, pentene, methylpentene, hexene, octene, and vinyl acetate, the melt index of 1 ~ 25gr / min Is preferably.

In the present invention, the compatibilizer is a block copolymer of styrene and ethylene copolymerized units and butylene and styrene copolymerized units (Styrene-Ethylene / Butylene-Styrene Block Copolymer: hereinafter referred to as “SEBS block copolymer”). Preference is given to grafting maleic anhydride or succinic anhydride to a polyolefin such as).

In the present invention, the organic lubricant is preferably at least one selected from the group consisting of ethylenebissteamide wax, liquid paraffin, paraffin wax, hydrocarbon process oil, and stearyl alcohol.

The three-layered polymer film according to the present invention provides a porous first layer for imparting lightweight and buffering properties necessary for exhibiting emboss reproducibility to the film, a second layer for imparting flame retardancy to the film, and imparting activity and light blocking properties to the film. It consists of a third layer. Therefore, since the three-layer polymer film according to the present invention has excellent mechanical strength, thermal stability, emboss reproducibility, and does not contain vinyl chloride, it does not generate hydrogen chloride during combustion and has excellent mechanical strength as a whole.

Hereinafter, the three-layer polymer film of the present invention and a manufacturing method thereof will be described in detail. However, unless stated otherwise, the weight percent refers to the weight percent based on the weight of the polyester resin.

The three-layer polymer film according to the present invention has a second layer in which a flame retardant is dispersed in a polyester resin on both surfaces of a porous first layer in which a polyolefin-based resin, a compatibilizer, and an organic lubricant are dispersed in a polyester resin. And a third layer formed by dispersing inorganic fine particles in the polyester resin.

In the present invention, the polyester resin is at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, the content of polyethylene terephthalate is 80% by weight or more and the limit It is preferable to use a viscosity of 0.5-0.7 dl / g. If the ultimate viscosity is less than 0.50 dl / g, the breaking strength of the final film is lowered, and if the ultimate viscosity exceeds 0.7 dl / g, there is a problem that the density of the final film is increased. The polyester resin is prepared according to a conventional polyester synthesis method, ethylene terephthalate of the repeating unit of the polyester resin is terephthalic acid or dimethyl terephthalate condensation polymerization of ethylene glycol, butylene terephthalate is terephthalic acid or dimethyl terephthalate and tetra Methylene glycol condensation polymerization, ethylene naphthalate is 2,6-naphthalenedicarboxylic acid or dimethyl-2,6-naphthalenedicarboxylate, condensation polymerization of ethylene glycol, butylene naphthalate is 2,6-naphthalenedicarboxyl It is formed by condensation polymerization of acid or dimethyl-2,6-naphthalenedicarboxylate and tetramethylene glycol.

In addition, the polyester resin may include a third copolymerization component in less than 40% by weight of the repeating unit. Monomers that can be used to form the copolymerization component are isophthalic acid, dimethyl-2,5-naphthalenedicarboxylate, 2,5-naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicar Acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, anthracenedicarboxylic acid or α, β-bis (2-chlorophenoxy) ethane-4,4-dicarboxylic acid, adipic acid Dibasic or polybasic acids such as 5-sodium sulfoisophthalic acid, trimellitic acid and pyromellitic acid, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, neopentylene glycol, polyethylene glycol, p-xylene And diols such as glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulfolesosinol.

In the present invention, the first layer is a porous layer formed by dispersing the polyester resin with a polyolefin resin, a compatibilizer for enhancing the compatibility of the polyester resin with the polyolefin resin, and an organic lubricant.

As the polyolefin resin contained in the first layer, one polymerized from at least one monomer selected from the group consisting of ethylene, propylene, butene, pentene, methylpentene, hexene, octene, and vinyl acetate is preferably used. For example, polypropylene, polyethylene, EVA resins and the like can be used. On the other hand, the melt index of the polyolefin resin is 1 to 25g / min is efficient for pore formation. The content of the polyolefin resin is preferably 5 to 30% by weight. When the content of the polyolefin resin is less than 5% by weight, it is difficult to form sufficient pores during stretching, resulting in a high density of the final film, and when the content of the polyolefin resin exceeds 30% by weight, breaking strength is lowered, resulting in poor film forming processability.

As said compatibilizer, it is preferable to use what grafted maleic anhydride or succinic anhydride to polyolefin like SEBS block copolymer. Here, in the above compatibilizer, the polyolefin has good affinity with the polyolefin resin, and the portion formed by grafting maleic anhydride or succinic anhydride has good affinity with the polyester resin. Thus, the compatibilizer promotes compatibility between the polyester resin and the polyolefin-based resin, thereby helping to uniformly mix both. The content of the compatibilizer is preferably 0.5 to 20% by weight. If the content of the compatibilizer is less than 0.5% by weight, the effect of improving the compatibility is not obvious, and if the content exceeds 20% by weight, the compatibility improvement effect no longer increases, but also increases the manufacturing cost.

As the organic lubricant, it is preferable to use 0.5 to 30% by weight of at least one selected from the group consisting of ethylenebissteamide wax, liquid paraffin, paraffin wax, process oil, and stearyl alcohol. Since the organic lubricant has a molecular structure in the form of a low molecular weight of the polyolefin-based resin, it is well kneaded with the polyolefin-based resin and maximizes the formation of micropores by increasing the incompatibility with the polyester resin during stretching. If the content of the organic lubricant is less than 0.5% by weight, fine pores are not effectively formed. If the content of the organic lubricant exceeds 30% by weight, the formation of micropores may be excessive and cause breakage during the film forming process.

The second layer laminated on one surface of the porous first layer is made by dispersing 5 to 40% by weight of a flame retardant in the polyester resin. If the flame retardant is less than 5% by weight, there is a problem that the flame retardancy is extremely weak, if the flame retardant exceeds 40% by weight, the flame retardancy does not increase any more and there is a problem that only the manufacturing cost rises. It is preferable to use phosphinic acid as said flame retardant.

The third layer, which is laminated on the surface opposite to the surface on which the second layer is laminated on one surface of the porous first layer, has optical properties such as light transmittance and color, and coefficient of friction, surface roughness, and fineness. It is made by dispersing inorganic fine particles for the purpose of adjusting the surface characteristics such as touch. At least one selected from the group consisting of titanium dioxide, calcium carbonate, barium sulfate, silica, kaolin, talc and zeolite may be used as the fine particles.

It is preferable that the average particle diameter of the said microparticles | fine-particles is 0.1-10 micrometers. If the average particle diameter is less than 0.1㎛ the effect on the optical properties and surface properties is insignificant, if it exceeds 10㎛ the surface roughness of the film is excessively increased to give a rough feeling. The content of the fine particles is preferably 0.01 to 15% by weight. If the content is less than 0.1% by weight, the control effect of the optical or surface properties is insignificant. If the content is more than 15% by weight, the optical or surface properties are deteriorated and the pressure increase is accelerated due to the clogging of the filter during the film manufacturing process. This leads to shortening, lowering production efficiency, poor dispersibility, increased breakage, and weight reduction. In addition, the polyester resins of the first to third layers include known additives such as ultraviolet absorbers, antistatic agents, heat stabilizers, electrostatic agents, crystallization accelerators, and the like within the scope of not impairing the effects of the present invention. can do.

On the other hand, in the three-layer polymer film according to the invention the thickness of the porous first layer is 50 to 80% of the total thickness of the three-layer polymer film, the thickness of the second layer is 15 of the total thickness of the three-layer polymer film It is preferable that it is% or less. If the thickness of the porous first layer is less than 50% of the total thickness of the three-layer polymer film, the buffer property and the light weight are deteriorated, so that the reproducibility of the embossing is poor, and if it exceeds 80%, the mechanical properties rapidly become poor. In addition, when the thickness of the second layer exceeds 15% of the total thickness of the three-layer polymer film, there is a problem that the manufacturing cost of the film increases.

The density of the three-layer polymer film is preferably 0.80 ~ 1.10g / cm ³ . If the density of the three-layer polymer film is less than 0.80g / cm ^3, there is a problem that the breaking strength is lowered, and the film forming process stability is lowered, and when the density of the three-layer polymer film exceeds 1.10g / cm ³ , the emboss reproducibility is lowered.

Next, the manufacturing method of the three-layer polymer film by this invention is demonstrated. In the present invention, the co-extrusion method for producing the three-layer polymer film is not particularly limited and may be a conventional known method.

For example, using a multi-manifold die or a feedblock die, the content of polyethylene terephthalate is at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. At least 80% by weight of polyester resin having an intrinsic viscosity of 0.5 to 0.7 dl / g, 5 to 30% by weight of polyolefin resin, and 0.5 to 0% of a compatibilizer for enhancing compatibility of the polyester resin with the polyolefin resin. To 20% by weight, and a polyester resin melt obtained by dispersing 0.5 to 30% by weight of an organic lubricant is extruded to form a first layer, and at the same time, 5 to 40% by weight of a flame retardant is contained in the polyester resin. Titanium dioxide, calcium carbonate, sulfur in the ester resin melt and the polyester resin At least one selected from the group consisting of barium, silica, kaolin, talc and zeolite, a polyester resin melt formed by dispersing 0.01 to 15% by weight of fine particles having an average particle diameter of 0.1 to 10 µm is disposed above and below the first layer. After stacking and co-extrusion to a second layer and a third layer, respectively, to prepare a melt sheet consisting of three layers, the melt sheet is cooled and solidified by bringing it into close contact with a cooling roll at 18 to 20 ° C. to form an unstretched sheet. .

At this time, in the final three-layer polymer film after stretching, the thickness of the first layer is 50 to 80% of the total thickness of the three-layer polymer film, the thickness of the second layer is 15% of the total thickness of the three-layer polymer film The co-extrusion rate should be adjusted so that the density of the three-layer polymer film is 0.80 to 1.10 g / cm ³ , and in the case of using a multi-manifold die, the die lip gaps of the second and third layers ( When the die lip gap) is adjusted to control the thickness, and the feed block die is used, the thickness of the second and third layers may be controlled by adjusting the discharge amount and the choke bar of each layer.

Since the organic lubricant is chemically similar to polyolefin, it is well mixed well with polyolefin resin, but maximizes incompatibility with the polyester resin while covering the outer wall of the polyolefin resin when stretched by melt extrusion. As a result, a large amount of micropores are generated in the film.

Meanwhile, the film may be lightened by containing a predetermined amount of a blowing agent in the first layer and foaming during the melt extrusion process to form fine pores in the first layer.

The blowing agent is suitably added 0.3 to 10% by weight based on the weight of the polyester resin of the first layer. If the addition amount is less than 0.3% by weight, the formation of micropores is generally uneven and the content of micropores is small, so there is no effect on light weight. When the amount is more than 10% by weight, the pores are excessively formed, which lowers heat resistance, numerical stability, and mechanical properties. And there is a problem that the process stability is poor during coextrusion. Examples of the blowing agent that can be used in the present invention include volatile blowing agents such as chlorofluorocarbon compounds such as 2-chloro-2-fluoromethane (freon 12) gas, chlorinated hydrocarbon compounds such as methylene chloride, and aliphatic hydrocarbon compounds such as propane gas and butane gas. Azo compounds such as azodicarbonamide and dazoaminobenzene, sulfohydrazide compounds such as benzene 1,3-disulfohydrazide, and N, N'-dinitroso-N, N'-dimethylterephthalamide Degradable blowing agents such as nitroso compounds such as, and amide compounds such as terephthalamide, and the like, and azo compounds, in particular azodicarbonamide, are preferred.

Subsequently, the three-layer unstretched sheet thus formed is stretched three to five times in one direction at 180 to 200 ° C, and the three-layer sheet is heat treated at 220 to 250 ° C. Subsequently, the three-layer sheet is stretched three to five times in the direction perpendicular to the one direction at 220 to 230 ° C. to form a three-layer polymer film, and the three-layer polymer film is heat treated at 200 to 250 ° C.

At this time, the organic lubricant in the stretching process can maximize the formation of micropores by increasing the incompatibility of the polyolefin resin and the polyester resin.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to the following Examples. Performance evaluation of the film produced in the following Examples was carried out in the following manner.

(1) extreme viscosity

After dissolving the polyester polymer in 25 ml of ο-chlorophenol by varying the weight, the relative viscosity was measured at 35 ° C. and then extrapolated to an infinite lean concentration (zero concentration).

(2) melt index

A sample weighing about 10 to 30 g was placed in a rheometer of DuPont, USA, and measured at a temperature of 160 to 170 ° C.

(3) film thickness

The cross section was observed using an electron scanning microscope manufactured by Jeol, Japan, and measured using an image analyzer.

(4) apparent density

The density gradient tube consisting of carbon tetrachloride and n-heptane was maintained at 25 ° C. and measured by the immersion method.

(5) breaking strength

After preparing a specimen 10cm x 30cm length using UTM 4206 of Instron of the United States, the tensile strength of the film was measured according to the ASTM D 882 method.

(6) process stability

The relative occurrence rate of the film was measured by measuring the frequency of breakage of the film for 12 hours during the film forming process.

A: 1 break or less occurs, B: 2 to 3 breaks, C: 4 or more breaks

(7) heat shrinkage

The specimen of 30 cm x 30 cm length was measured after leaving it for 30 minutes in 150 degreeC hot air oven. At this time, the heat shrinkage was calculated as follows.

Example 1

After mixing dimethyl terephthalate and ethylene glycol in a 1: 2 equivalent ratio, 0.05 wt% of tributylene titanate was added to the mixture to condensate low molecular weights of bis-2-hydroxyethyl terephthalate (BHET) and BHET. Water was formed. Here, 1.0% by weight of trimethylene terephthalate as a heat stabilizer and 1.0% by weight of antimonitriacetate as a polymerization catalyst were added, and polycondensation was completed to prepare a polyester resin having an intrinsic viscosity of 0.610 dl / g.

The polyester resin is mixed with a random polypropylene resin having a melt index of 4.0 g / min at a ratio of 80:20, and maleic anhydride is grafted to the SEBS block copolymer as a compatibilizer based on the polyester resin. % And 3.0 wt% of N, N'-ethylene bis-stearamide wax was added as a lubricant to obtain a first polyester resin by a conventional compounding method.

In the polymerization process of the polyester resin, after the transesterification reaction is finished, 20% by weight of phosphinic acid is added to the polymerization tank based on the polyester, and the polymerization reaction is completed, thereby obtaining a second polyester resin having an ultimate viscosity of 0.610 dl / g. Was prepared.

To the polyester resin was added titanium dioxide having a cubic crystal structure with an average particle diameter of 0.5 μm based on the polyester resin and compounding 5 wt% to prepare a third polyester resin.

After drying the first to third polyester resins, the first polyester resin is extruded as a first layer as a center layer by using an extruder and a feed block equipped with a die die, and at the same time, the second polyester resin And the third polyester resin to be the second layer and the third layer, respectively, which are surface layers, and further co-extruded so that the thickness ratio of the first layer: second layer: third layer is 10: 75: 15. A melt sheet was prepared. The 3-layer melt sheet was cooled and solidified by bringing it into close contact with a cooling roll at 20 ° C to form a 3-layer unstretched sheet. Subsequently, the three-layer unstretched sheet thus formed is stretched four times in the longitudinal direction at 180 ° C, and the three-layer sheet is heat-treated at 220 ° C.

Subsequently, the three-layer sheet was stretched four times in the transverse direction at 220 ° C. to form a three-layer polymer film. Subsequently, the three-layer polymer film was heat-treated at 230 ° C. to manufacture a three-layer polymer film having a thickness of 100 μm. The physical properties of the three-layer polymer film thus produced are shown in Table 1.

Example 2

The same as in Example 1, except that polyethylenenaphthalate resin having an intrinsic viscosity of 0.59 dl / g prepared using dimethyl-2,5-naphthalenedicarboxylate instead of dimethylterephthalate as a dicarboxylic acid component was used. A three-layer polymer film was produced by the method and the physical properties thereof are shown in Table 1.

Examples 3-5 ''

Except for changing the thickness of the porous first layer as shown in Table 1, a film was prepared in the same manner as in Example 1, and the physical properties thereof are shown in Table 1. The three-layer polymer film obtained in Examples 1 to 5 had a low density and was excellent in light weight.

Comparative Examples 1 to 5

Except for changing the thickness of the porous first layer as shown in Table 1, a film was prepared in the same manner as in Example 1, and the physical properties thereof are shown in Table 1. As shown in Table 1, when the thickness of the porous first layer is small, the density of the three-layer polymer film was increased and the lightness was lowered. On the contrary, when the thickness of the porous first layer was too large, coextrusion film forming processability and breaking strength were poor.

Polyester used in the first, second and third layers Porous first layer 2nd layer 3rd floor Final physical properties of three-layer polymer film Poly Olefin thickness Flame retardant thickness Inorganic particulates thickness Fairness density Hydrothermal rate Breaking strength unit - - Μm - Μm - Μm - g / cm ³ % kg / cm ² Example 1 PET PP 75 Phosphinic acid 10 TiO ₂ 15 A 0.850 0.5 1400 Example 2 PEN PP 75 Phosphinic acid 10 TiO ₂ 15 A 0.910 0.3 1520 Example 3 PET PP 50 Phosphinic acid 10 TiO ₂ 40 A 1.100 0.3 1480 Example 4 PET PP 60 Phosphinic acid 10 TiO ₂ 30 A 1.020 0.3 1440 Example 5 PET PP 80 Phosphinic acid 10 TiO ₂ 10 A 0.820 0.5 1350 Comparative Example 1 PET PP 30 Phosphinic acid 10 TiO ₂ 60 A 1.410 0.3 1750 Comparative Example 2 PET PP 40 Phosphinic acid 10 TiO ₂ 50 A 1.370 0.2 1695 Comparative Example 3 PET PP 45 Phosphinic acid 10 TiO ₂ 45 A 1.355 0.3 1550 Comparative Example 4 PET PP 48 Phosphinic acid 10 TiO ₂ 42 A 1.310 0.3 1535 Comparative Example 5 PET PP 85 Phosphinic acid 10 TiO ₂ 5 B 0.840 0.9 1250

PP: Polypropylene TiO ₂ : Titanium Dioxide

PET: Polyethylene terephthalate PEN: Polyethylene naphthalate

As described above, the three-layer polymer film according to the present invention is a porous first layer imparting the light weight and buffering properties required to exhibit emboss reproducibility to the film, a second layer imparting flame retardancy to the film, and an active film to the film. It consists of a third layer to give. Therefore, the three-layer polymer film according to the present invention is excellent in emboss reproducibility and does not contain vinyl chloride, so it does not generate hydrogen chloride during combustion, and has excellent thermal stability and mechanical strength as a whole.

Claims (8)

At least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate and having a content of polyethylene terephthalate of 80% by weight or more and an intrinsic viscosity of 0.5 to 0.7 dl / g 5 to 30% by weight of polyolefin resin in the ester resin, 0.5 to 20% by weight of a compatibilizer for improving compatibility between the polyester resin and the polyolefin resin, and 0.5 to 30% by weight of an organic lubricant. Porous first layer made by; At least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate and having a content of polyethylene terephthalate of 80% by weight or more and an intrinsic viscosity of 0.5 to 0.7 dl / g A second layer formed by dispersing 5 to 40% by weight of a flame retardant in the ester resin and laminated on any one surface of the porous first layer; And At least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate and having a content of polyethylene terephthalate of 80% by weight or more and an intrinsic viscosity of 0.5 to 0.7 dl / g At least one selected from the group consisting of titanium dioxide, calcium carbonate, barium sulfate, silica, kaolin, talc, and zeolite in the ester resin is made by dispersing 0.01 to 15% by weight of fine particles having an average particle diameter of 0.1 to 10 μm. Three-layered polymer film comprising a third layer laminated on any one surface of the porous first layer. The thickness of the porous first layer is 50 to 80% of the total thickness of the three-layer polymer film, the thickness of the second layer is characterized in that less than 15% of the total thickness of the three-layer polymer film. 3-layer polymer film. The method of claim 1, wherein the density of the three-layer polymer film, Three-layer polymer film, characterized in that 0.80 ~ 1.10g / cm ³ . The method of claim 1, wherein the flame retardant, Three-layer polymer film, characterized in that phosphinic acid (phosphinic acid). The method of claim 1, wherein the polyolefin resin, A three-layer polymer film, which is polymerized from at least one monomer selected from the group consisting of ethylene, propylene, butene, pentene, methylpentene, hexene, octene, and vinyl acetate, and has a melt index of 1 to 25 gr / min. The method of claim 1, wherein the compatibilizer, 3 layer polymer film characterized in that maleic anhydride or succinic anhydride is grafted to polyolefin resin. The method of claim 6, wherein the polyolefin resin, A three-layer polymer film, characterized in that the block copolymer of the unit copolymerized with styrene and ethylene and the unit copolymerized with butylene and styrene. The method of claim 7, wherein the organic lubricant, At least one selected from the group consisting of ethylenebissteamide wax, liquid paraffin, paraffin wax, process oil, and stearyl alcohol.