KR100193689B1 - Polymer film and its manufacturing method - Google Patents

Abstract

In the present invention, a polyester resin, a polyolefin-based resin and a methacrylate compound represented by the following Chemical Formula 1 are mixed to prepare a mixed resin composition, and then inorganic particles are added to the mixed resin composition, followed by melt kneading, extrusion, A method of manufacturing a polymer film is disclosed by quenching and forming a sheet, followed by drawing the sheet. The polymer film produced by this method has a proper balance of the properties of the material resin, The texture is suitable for use as a paper substitute.

Wherein R is an epoxy, lactam, caprolactam or oxazoline group.

Description

Polymer film and its manufacturing method

The present invention relates to a polymer film based on polyester and a method for manufacturing the same, and more particularly, to a method for producing a polymer film and a method for improving the texture of a film by improving compatibility between a polyester resin and a polyolefin resin. It relates to a polymer film produced by.

As the industry advances, the need for new materials with properties for a variety of applications is increasing. In particular, if paper has been used as a basic material, which has been widely used at a very low price, manufacturing costs will gradually increase due to rising raw material costs due to rising paper prices, regulations on nature conservation, and supply imbalance due to resource limitations. In addition, due to the inherent properties of the paper, which is difficult to preserve for a long time due to the penetration of moisture and bacteria, and weak strength, heat resistance, etc., the need for the development of a plastic material that can replace the paper is increasing day by day.

The most widely used resins in the present industry include polyolefin resins represented by polyethylene and polypropylene, polyester resins represented by polyethylene terephthalate, and polyvinyl chloride and polystyrene. However, polyvinyl chloride has tended to be stagnant or gradually decreased due to the toxicity of chlorine gas generated during combustion, while polystyrene is excellent in transparency and post-processing, but the price of raw resin in the product continues to rise. In addition, due to the toxic gas generated in the manufacturing process and the black dust generated during the combustion, there is a significant burden in terms of environmental protection. On the other hand, polyolefin resins, which have no concern about environmental pollution, have the disadvantage of low price and good processability but poor mechanical properties.Polyester resins have excellent mechanical properties and dimensional stability but lack post-processing and flexibility. The disadvantage is that.

More specifically, polyester resins include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, etc. In particular, polyethylene terephthalate (PET) is chemically and physically stable, high mechanical strength, heat resistance, durability, It is widely used as a material for medical and various industrial equipments because of its excellent chemical resistance. Especially, it has excellent properties such as elastic modulus, dimensional stability, and activity, and it is used for magnetic recording media, capacitors, packaging materials, photographic films, labels, etc. Widely used for various purposes. In particular, the amount of usage is increasing as a material such as an award paper for label printers, an award paper for barcode printers, poster papers, calendars, maps, photo papers, copy papers and printed publications for special purposes. However, polyester alone is excessively stiff and not only different from the texture, but also does not give a paper-like feeling in transparency or color, and has a disadvantage in that the density of the polyester itself is high.

On the other hand, polyolefin resins include low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polybutylene, polymethylphenene, etc. Among these, polypropylene, which is widely used for stretched films, has a density of 0.90 to 0.92 g in general-purpose plastics. It is one of the lightest / cm3 and is transparent, it is excellent in heat resistance, electric heat resistance, chemical resistance and bending resistance, and it is harmless and nontoxic, so it has excellent workability but cold resistance is weak. In order to compensate for these drawbacks, ethylene and other olefinic monomers are copolymerized and used and classified into homopolymers, random copolymers and impact copolymers according to the presence or absence of such low molecular copolymers and copolymerization structure. Homopolymers have high crystallinity, high melting point and good rigidity. Random copolymers have excellent transparency but low crystallinity, melting point and stiffness, and impact copolymers have particularly good impact resistance.

Therefore, in order to improve the impact resistance, heat resistance, durability, chemical resistance, environmental resistance and post-processing properties to be used not only as a simple paper substitute material but also as a variety of packaging materials, the polyethylene terephthalate resin and the polyethylene resin are blended to provide excellent characteristics of each other. Various methods have been developed to supplement the shortcomings of each other while giving a paper-like texture.

In Japanese Patent Laid-Open Nos. 62-243120 and Pyeongseong 2-206622, inorganic particles are added to polyesters. In Japanese Patent Laid-Open Nos. 58-50625, a polyester is used to reduce the weight of the polyester. In Japanese Patent Laid-Open No. 57-49648 and No. 63-166441, polyolefin resin is blended and stretched in polyester to form fine pores on the surface and inside of the film to simultaneously improve the surface properties and tendency of the film. Pursued. However, since polyester resin and polyolefin have very poor compatibility, simple kneading by the above method has many problems. That is, layer separation between resins may occur, and micropores (voids) may be generated in the manufacturing process of the film to reduce weight, but surface characteristics may be poor, resulting in poor printability and mechanical properties.

Therefore, in the present invention, by adding a compatibilizer to form a specific functional group in the polyester resin, the kneading compatibility with the polyolefin is improved to improve texture, at least uniaxially stretched polymer film with improved mechanical properties, light weight, and post-processability. It is an object of the present invention to provide a method for producing and a polymer film produced by the method.

In order to achieve the above object, in the present invention, (a) a polyester resin having an intrinsic viscosity of 0.4 to 0.9 dl / g, and a melt index of 5 to 40% by weight relative to the polyester resin is 1.0 to 20 (g / 10 minutes) to prepare a mixed resin composition by mixing a polyolefin resin, 1 to 10% by weight of the methacrylate compound represented by the formula (1) relative to the polyolefin resin, (b) a composition solid content in the mixed resin composition Adding 5-30% by weight of inorganic particles by weight, (c) melting and kneading, extruding and quenching the composition obtained in step (b) to form a sheet, and (d) drawing the sheet. There is provided a method of producing a polymer film comprising:

[Formula 1]

Wherein R is an epoxy, lactam, caprolactam or oxazoline group.

Preferably, the stretching step further includes (e) applying heat to the surface of the stretched sheet and then applying a dispersion containing an antistatic material to the heat setting.

As the antistatic material, a quaternary ammonium salt represented by the following Chemical Formula 2 is preferable.

[Formula 2]

Wherein R ₁ is an alkyl group having 10 to 20 carbon atoms, R ₃ and R ₄ are alkyl groups having less than 5 carbon atoms, R ₂ is a hydrocarbon having a chain structure of less than 4 carbon atoms, and X ⁻ is a counter anion .

Preferably, in the step (e), the coating treatment is performed such that 0.01 to 0.1 g / m 2 exists on the surface of the film on which the solid active ingredient is prepared.

Preferably, the methacrylate compound represented by the formula (1) has a molecular weight of 2,000 to 30,000.

The inorganic particles have an average particle diameter of 0.1 to 10 μm, and are at least one selected from the group consisting of titanium compounds, barium sulfide, kaolin, calcium carbonate, silica, and talc.

Preferably, the melt kneading step is performed using a compound under the following conditions.

1.Temperature condition (T _i : initial inlet temperature of compounder, T _f : final outlet temperature)

210 ℃ <T _i <250 ℃

T _f = T _i + 40 ° C

2. Residence time in compounder (t)

1 minute 〈t 〈5 minutes

3. Final discharge resin temperature (t)

T _f + 5 ° C <T _p <T _f +10 ° C

At least one axial stretching is performed in the stretching step, and the stretching conditions are not particularly limited.

Another object of the present invention is achieved by a polymer film produced by the above method. The polymer film produced by the method of the present invention has a specific gravity of 0.9 to 1.2 g / cm 3 and is suitable for use as a paper substitute substrate.

Hereinafter, the present invention will be described in more detail.

Polyester polycondenses the acid component which has aromatic dicarboxylic acid as a main component, and the glycol component which has alkylene glycol as a main component. Specific examples of the aromatic dicarboxylic acid include dimethyl terephthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid and diphenyl ether dicarboxylic acid. Carboxylic acid, anthracenedicarboxylic α, β-bis (2-chlorophenoxy) ethane-4,4 'dicarboxylic acid, and the like, among which dimethyl terephthalic acid and terephthalic acid are particularly preferred. Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol and the like, and among these, ethylene glycol is particularly preferable. The polyester of the present invention is preferably at least 60 parts by weight copolymerized within 40 parts by weight of a homo polyester or polyethylene terephthalate. Specific examples of the copolymerization components include diol compounds such as diethylene glycol, propylene glycol, neopentyl glycol, ethylene glycol, p-xylene glycol, 1,4-cyclohexanedimethanol, 5-sodium sulforezocin, adipic acid, And dicarboxylic acids such as 5-sodium sulfoisophthalic acid, trimellitic acid and pyromellitic acid.

In addition to the polyester, additives such as polycondensation catalysts, dispersants, electrostatic agents, crystallization promoters, nucleating agents, antiblocking agents and the like may be added within a range that does not impair the effects of the present invention.

As the polypropylene, at least one selected from the group consisting of low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, and polybutylene is preferably used. In the present invention, in order to improve the properties and the like of the stretched film to a desired level, it is preferable to use a propylene copolymer resin having a melt index of 1 to 20 (g / 10 minutes) and a melting point of 140 to 180 ° C.

In the present invention, the methacrylate compound serves as a medium for improving the compatibility with the polyolefin resin by easily reacting with the polyester resin to form a hydroxyl group (-OH) or a carboxyl group (-COOH) on the resin surface.

A step-by-step process of first reacting the polyester and the methacrylate-based compound and then kneading the polyolefin resin is also possible, but for simplicity of the process, the reaction and the kneading are preferably performed simultaneously. Thus, in order to simultaneously perform reaction and kneading | mixing, it is preferable to use a compound reactor.

Compounds can be used in either a uniaxial screw type or a twin screw type, but mixing of polyester is preferably carried out using a twin screw type compounder. According to the direction of the screw is divided into two directions and the same direction, they show a difference in kneading, but all can be used. Compounding refers to the incorporation of two or more solids at a constant component ratio to remove (mix) the heterogeneity of the mixture components at a constant temperature and a certain residence time, and to discharge, cool, and cut (chip-form) the outside to move and transport. This is a series of processes that make it easy and then melted again if necessary to form a film-like form. The compounder in charge of this process is divided into solid transfer zone, melting zone, and discharge zone according to the area, and the solid transfer zone transfers the powder in the solid state along the berel and transfers it to the melting zone. The region induces the flow of the fluid by heat conduction from the heat source around the barrel and activates the flow of the fluid through heat exchange so as to uniformly advance the melting, or by converting the mechanical energy generated by the rotation of the screw into the plastic deformation of the solid, The frictional heat with the berel, the viscous flow of the fluid is converted into thermal energy to play a role in melting. The melt mixed resin is pushed out through the discharge area. In compounding, the optimum process condition is to maintain the lowest potential energy while maintaining the highest dispersibility. The variables controlling this include berel temperature, screw rotation speed, and L / D ratio. In particular, in the case of mixing the two polymer resins that are not miscible with each other as in the present invention, a dispersion technique in the compound is further required to increase the degree of mixing. In order to increase the shear stress, it is also a preferable method to allow sufficient mixing to be performed by passing the injected resin through the wide melting zone (melting point).

In order to increase the mixing degree between the polyester resin and the polyolefin resin, the dispersion index K value defined as follows should be high.

: 전단응력.

: 전단속도here,

: Shear stress.

: Shear rate

: 계면장력,

: 분산상의 폴리올레핀 수지 입경.

: Interfacial tension,

: Polyolefin resin particle size of dispersed phase.

In order to increase the K value, it is necessary to set the process conditions so that the shear stress and the shear rate are large, and the interfacial tension and the particle size in the emulsion state (here, the particle diameter of the polyolefin resin particles) are as small as possible.

When the methacrylate-based compound reacts with the polyester, -OH group or -COOH group is generated to decrease the interfacial tension of the resin, thereby increasing the dispersion index and improving compatibility with the polyolefin. At this time, the amount of the methacrylate compound is preferably 1 to 10% by weight based on the weight of the polyolefin resin. When the added amount of the methacrylate compound exceeds 10% by weight, a self-reaction between the methacrylate compounds may occur, and thus the dispersion index may fall. In this case, the addition of a small amount of polystyrene may prevent the lowering of the dispersion index, but it is not preferable in that other by-products are generated.

In the kneading process, the mixing ratio of the polyolefin resin is suitably 5 to 40% by weight with respect to the polyester resin, when the two resins are mixed in this range can achieve a light and paper-like texture at a desirable level Because.

The reaction and kneading process conditions in the compounding as described above are as follows.

That is, when uniformly mixing polyester and polyolefin resin, although there is a slight difference depending on the physical properties and the amount of the polyolefin resin to be mixed, the initial inlet temperature (T _i ) is preferably in the range of 210 ℃ to 250 ℃, 220 ℃ ~ 240 It is more preferable if it is ° C. If it is less than 210 ℃, it will not only damage the equipment due to excessive load on the screw, but also cause unmelted resin, and if it is higher than 250 ℃, the reverse flow of molten resin will occur, making it difficult to produce smoothly and used as a compatibilizer. The decomposition of organic compounds is accelerated. The final outlet temperature T _f , which is in the form of a mixed molten resin, is preferably in the range of 250 ° C. to 290 ° C., more preferably in the range of 260 ° C. to 280 ° C. If it is lower than 250 ℃, effective dispersion between two resins cannot be expected. If it is higher than 290 ℃, thermal decomposition may occur due to excessive high temperature, resulting in sulfidation or extremely low viscosity, resulting in high quality film or molded product. Can't expect

In compounding, the residence time t in the compound is preferably 1 minute to 5 minutes, and more preferably 2 minutes to 4 minutes. If the residence time is less than 1 minute, the contact time and contact area between the polyester resin and the polyolefin resin may not be sufficient to obtain a desirable mixing effect. If the residence time exceeds 5 minutes, thermal degradation may occur due to excessive heat supply, resulting in deterioration of quality.

In addition, the final discharge resin temperature (T _P ) is preferably in the range of 255 ° C to 300 ° C, more preferably in the range of 270 ° C to 290 ° C. In the case of melting and mixing the polyester resin and the polyolefin resin, it is necessary to apply more heat than the polyester resin alone to obtain desirable physical properties through smooth melt mixing. Such process conditions are not only possible by temperature control but can be achieved by appropriately adjusting variables such as the specifications of the compounder (L / D), the resin discharge amount, the rotational axial flow rpm, and the like.

In general, as the amount of polyolefin added increases, it is desirable to adjust the process temperature and rotation speed up, since sufficient energy is required to mix. In addition, the mixed melt between two resins having poor compatibility with each other is more effective to use a biaxial rotary shaft compounder than a uniaxial rotary shaft.

In order to produce good quality mixed-melted master chips, it is necessary to remove the generated moisture, and in particular, it is more effective to use a resin sufficiently dried in advance.

In addition, in order to retain the whiteness and concealability such as paper, there is a limit only in the resin itself, and it is preferable to add inorganic particles having an average particle diameter of 0.1 to 10 µm. As the inorganic particles, at least one selected from the group consisting of a titanium compound, barium sulfide, kaolin, calcium carbonate, silica, and talc is used in an amount of 5 to 30 wt% based on the weight of the final film. In the compounding, the inorganic particles may be simultaneously introduced through a polyester or polyolefin resin inlet, and may be separately added through a separate side feeder. If the average particle size of the particles is smaller than 0.1 μm, a large amount of particles will not only escape through the vacuum outlet in the compounding process, but also agglomerates will appear severely on the film. . On the other hand, when the average particle diameter exceeds 10 μm, the pressure applied to the compounder or the extruded filter may be high, which makes it difficult to use the device for a long time, resulting in poor productivity and uniform dispersion in the resin.

The good kneading | mixing chip manufactured by the above process is extended | stretched by the conventional film extending | stretching method.

Step-by-step process operation from heat melting to heat setting will be described in detail.

First, the resin is extruded in a conventional manner to form a sheet. In this molding process, it is common to form a predetermined shape after heat melting using an extrusion molding machine, but the molding material may be molded in a softened state without heat melting. At this time, as the extrusion machine, both a single screw extrusion machine, a biaxial coaxial or a two-way extrusion machine can be used. In addition, the molten resin can be obtained at the same time by passing through a filter having a mesh of a constant size kneading effect and foreign matter removal effect, the filter used is more than 100 mesh, but more preferably 400 mesh or more. As a mesh filter, it is good to select a suitable filter in consideration of pressure resistance and strength, and the shape of the mesh can be used by selecting a suitable one such as a flat plate or a cylinder. Here, the extrusion conditions are not particularly limited, but may be appropriately adjusted according to a given situation. Preferably, the extrusion temperature is selected from the melting point of the resin to a temperature range about 50 ° C. higher than the decomposition temperature. Melting is not possible at a temperature lower than the melting point. If it is too high, the decomposition phenomenon becomes remarkable, causing sulfidation and deterioration and foaming in the extruder. Dies to be used include a tee-die and a ring holder.

Next, the sheet obtained by extrusion molding is cooled and solidified. In this case, a metal roll using a refrigerant such as gas or liquid is generally used. In the case of using a metal roll, it is possible to obtain an effect of making the thickness of the sheet uniform or improving the surface properties. The cooling temperature is generally selected within the glass transition temperature range of the sheet, and is generally selected within the range of 0 ° C to 20 ° C, and the cooling rate is determined within the range of 3 to 200 ° C / sec. If the temperature is below 0 ℃, the cooling speed is faster than necessary and the rigidity of the sheet is increased momentarily, so that the melt flows in the wave shape during the solidification, so that stable molding cannot be achieved. If the temperature exceeds 20 ℃, the crystallinity of the solidified molding is increased. Elongation is poor.

Subsequently, a process of simultaneously or sequentially performing cooling solidified sheets on at least one axis is performed. At this time, in order to raise the uniformity of film thickness, sequential stretching is more preferable. In particular, multi-stretching can provide better mechanical properties.

In the case of longitudinal stretching, ie, uniaxial stretching in the film forming line direction, it is necessary to heat the sheet surface. The stretching temperature is not particularly limited, but a temperature between the glass transition temperature of the sheet and the cold crystallization temperature is preferable. If the stretching temperature is lower than the glass transition temperature, the stretching becomes poor because the softening is not sufficiently performed. If the stretching temperature is exceeded, the crystallization proceeds excessively and uniform mechanical properties cannot be obtained. The draw ratio is not particularly limited and is usually in the range of 2 to 5 times. If the stretching ratio is less than 2 times, the stretching effect cannot be obtained, and if the stretching ratio exceeds 5 times, the lateral stretching becomes difficult.

The film first drawn in the longitudinal direction is stretched again in the transverse direction, ie, in the 90 ° direction of the film continuous direction. The stretching method is not particularly limited. The temperature at the time of transverse stretching is generally selected within a temperature range of 5 ° C or higher above the glass transition temperature and 30 ° C below the melting point. If the stretching temperature is too low, the softening is insufficient, and the stretching becomes difficult. On the contrary, if the stretching temperature is too high, the surface is partially dissolved to obtain a uniform thickness. Lateral draw ratio is not particularly limited, but generally 3 to 10 times the range is good. If the draw ratio is less than 3 times, the transverse mechanical strength is not sufficient, and if it exceeds 10 times, the breakage is likely to occur. The stretching speed is usually 1 × 10 to 1 × 10 ⁵ % min.

In order to improve the surface properties of the stretched film and impart antistaticity, a process of applying an additive may be performed. At this time, the coating method may be any known coating method such as roll coating, extrusion coating, spray coating, curtain coating, it is preferable to use a roll method in terms of processability and workability. This coating step may be carried out before the stretching step. The coating amount is adjusted so that the solid active ingredient of the additive is present in the film surface of 0.01 ~ 0.1g / ㎡. If the coating amount on the surface of the film is less than 0.01g / ㎡ can not be expected antistatic effect, if it exceeds 0.1g / ㎡, the antistatic properties are good, but the adhesion phenomenon between the film occurs difficult to normal production. In the present invention, the additive applied to impart an antistatic effect is preferably a quaternary ammonium salt compound. Examples thereof include butyloxyethylammonium, hydroxyethylammonium, orthodecyloxyethylammonium salt, bishydroxydecylpropylammonium salt, hydroxybutylammonium salt, dodecyloxybutylammonium salt, ethylammonium salt and the like, but are not limited thereto. no. The ammonium salt is preferably dissolved in purified water and used at a concentration of 1 to 10% by weight. If the aqueous solution concentration is less than 1% by weight, sufficient antistatic properties cannot be imparted, and uncoated areas are generated, resulting in uneven physical property variation. It may occur. In addition, when the aqueous solution concentration exceeds 10% by weight, undissolved particles are present, resulting in a problem of poor appearance and adhesive strength after printing.

In addition to the above resin, known additives such as antistatic agents, slip agents, antioxidants, ultraviolet stabilizers and the like can be added within a range that does not impair the effects of the present invention.

In order to impart dimensional stability, heat resistance and uniformity of strength to the stretched film obtained as described above, it is preferable to perform heat setting at a high temperature. Although heat setting is a conventional process, the stretched state, relaxed state or limited shrinkage of the stretched film is preferred. It is preferably carried out for 0.5 to 120 seconds at a temperature about 100 ℃ lower than the melting point of the film under the condition. In addition, the heat setting may be carried out two or more times by changing the conditions within the above range, it can be carried out in the atmosphere as well as argon gas or nitrogen gas or a mixed gas thereof as well as general air. If the heat-setting step is not performed, deformation may occur particularly near the glass transition temperature, and problems may occur during post-processing or actual use. The heat setting temperature should be determined according to the speed of the film passing through the atmosphere, that is, the treatment time, and the treatment time is determined according to various conditions, but it is generally good to be 3 minutes or less. If the heat treatment time is long, deformation occurs, such as an increase in the film during molding.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited only to the following examples.

Evaluation of various performances on the film and process prepared in Examples and Comparative Examples of the present invention was carried out by the following method.

(1) apparent density

The density gradient tube consisting of carbon tetrachloride and normal heptane was maintained at 25 ° C. and measured by ups and downs.

(2) breaking strength

Breaking strength was measured using an Instrong measuring instrument (Model: 4206) according to ASTM D882.

(3) surface roughness

The surface roughness (Ra) was measured under the condition of cut-off 0.25 mm using a contact type two-dimensional surface roughness measuring instrument (model name: SE-30D) manufactured by Kosaka (Kosaka, Japan).

(4) coefficient of friction

It measured on the conditions of the load of 205g and the speed | rate 150mm / min using the surface tester (model name: Heidon-14) of Heidon (Japan).

(5) whiteness

The whiteness was measured at 550 nm among visible wavelengths using the colorimeter (model name: SZS-∑ 80) of the full color industry (Japan).

(6) surface resistance

The surface resistance was measured using the insulation resistance measuring device of the United States Hewlett, the temperature of 20 ℃, 65% relative humidity, 500V applied voltage.

(7) polyolefin particle size measurement

The size of the polyolefin spherical particles dispersed in the film was measured and statistically arithmetic averaged by using SEM (model name: JSM-840A) manufactured by Zeol Corporation.

Example 1

After terephthalic acid and ethylene glycol were added in a 1: 2 equivalent ratio to form bis-2-hydroxyethyl terephthalate as a polyethylene terephthalate monomer, a polycondensation catalyst was added to complete the condensation condensation reaction, and the ultimate viscosity was 0.610 dl / g. Phosphorus polyester resin was obtained. Here, 20% by weight of the final film weight of homo polypropylene resin having a melt index of 16.6 (g / 10min) and a melting point of 160 ° C, 2% by weight of glycidyl methacrylate (GMA) of the polypropylene resin, particle diameter 15 weight% of this 0.8 μm titanium compound was put into a biaxial coaxial compounder (device name: ZSK25) having an L / D of 40 and kneaded to obtain a polymer chip. At this time, the initial inlet temperature of the compounder was 240 ° C, the final outlet temperature was 280 ° C, the screw rpm was 350, and the temperature of the mixed molten resin discharged was 285 ° C. The chip with improved kneading property is discharged under the conditions of the extrusion temperature of 205 ℃, screw rpm 120, and 270kg of discharge rate per hour through the drying process, and then quenched by passing the casting roll (cooling) at 10 ℃. I made a transparent sheet. The quenched sheet was uniaxially stretched three times in the longitudinal direction at 120 ° C., and then stretched four times in the transverse direction at 150 ° C. and heat-set at 200 ° C. with a thickness of 20 μm. The coating of the film surface was carried out in the state of being stretched in the longitudinal direction, but by applying a 3% aqueous solution of butyloxyethylhydroxyethylammonium, the coating amount of the film surface finally obtained was 0.03 g / m 2.

The 20μm thick film wound through this step process has a breaking strength of 17kg / mm2, specific gravity of 1.05, surface roughness (Ra) of 0.025㎛, coefficient of friction of 0.26, and excellent texture and mechanical properties. Excellent. In particular, a film having a good surface resistance of 10 ¹⁰ Ω and good antistatic property and good stretching balance in the longitudinal and transverse directions was obtained. As a result of observing the dispersion state and particle diameter of the polyolefin in the film cross section, it was confirmed that the dispersion was satisfactory with an average particle diameter of 8 μm.

Examples 2-5

Example 1 was carried out in the same manner as the final concentration of the composition and the process conditions were changed as shown in Table 1. The physical properties of the film thus prepared are shown in Table 1.

Comparative Example 1-5

Example 1 was carried out in the same manner as the final concentration of the composition and the process conditions were changed as shown in Table 1. The physical properties of the film thus prepared are shown in Table 1.

TABLE 1

Polyolefin Inorganic particles Methacrylate Melt extrusion conditions Application amount Characteristics of the final film Kinds Melt index Amount Kinds Particle diameter Amount Temperature conditions Residence time importance Breaking strength Surface roughness Coefficient of friction Whiteness Specimen resistance PO particle size Ti T ₃ T ₅ Tf Tp - g / 20 minutes wt.% - Μm wt.% wt.% ℃ g / m ² - kg / mm ² Μm - % Ω Μm Example One PP 16.6 20 titanium 0.8 15 2 240 260 275 280 285 2.5 0.03 1.05 17 0.025 0.26 91 10 ¹⁰ 8 2 HDPE 7.2 10 titanium 1.2 12 One 245 263 271 285 290 3.2 0.05 1.18 18 0.019 0.32 90 10 ¹⁰ 8.5 3 PP 6.0 15 Talc 2.0 10 4 242 265 270 282 287 3.1 0.02 1.12 17 0.027 0.30 89 10 ¹⁰ 7.1 4 LDPE 1.5 30 Silica 0.6 20 8 240 263 276 280 285 2.5 0.06 1.02 19 0.016 0.25 90 10 ⁹ 6.5 5 PMP 9.1 40 titanium 0.4 11 3 241 266 270 281 286 2.2 0.04 1.11 19 0.011 0.26 91 10 ¹⁰ 6.1 Comparative example One PP 15 30 - 0 0 0 205 218 221 220 230 2.1 0 1.32 8 0.027 0.32 82 10 ¹⁵ 25 2 HDPE 12 20 Silica 0.05 15 2 260 279 297 305 342 2.4 0.02 1.35 7 0.021 0.29 91 10 ¹² 12 3 PP 19 20 titanium 0.4 2.4 3 240 256 266 274 281 0.5 0.30 1.25 14 0.019 0.21 85 10 ¹⁰ 18 4 PP 16 10 titanium 0.6 4.1 15 240 261 268 271 275 6.4 0 1.28 15 0.020 0.27 83 10 ¹⁵ 19 5 PP 15 10 Talc 2.9 2.5 One 240 261 268 271 275 6.4 0.01 1.35 15 0.019 0.22 81 10 ¹¹ 12

Note: ^{1 Addition} is weight percent based on the weight of polyester resin

^{2 The} amount added is based on the weight of the film by weight ³

% By weight based on weight of polyolefin resin.

Ti: Initial inlet temperature of the compounder, T ₃ : Melting temperature, T ₅ : Extrusion temperature

Tf: final outlet temperature of the compounder, Tp: discharge resin temperature

As described above, according to the present invention, the miscibility between the polyester resin and the polyolefin resin is greatly improved by the addition of a compatibilizer, thereby obtaining a polymer film having a texture suitable for replacing paper. Therefore, it can be widely used in many related industries using paper.

Claims (9)

In the manufacturing method of the polymer film, (a) a polyester resin having an intrinsic viscosity of 0.4 to 0.9 dl / g, a polyolefin resin having a melt index of 5 to 40% by weight with respect to the polyester resin of 1.0 to 20 (g / 10 minutes), and the polyolefin resin. Preparing a mixed resin composition by mixing 1 to 10% by weight of a methacrylate compound represented by Formula 1; (b) adding 5 to 30% by weight of inorganic particles based on the weight of the composition solids in the mixed resin composition, (c) melting and kneading, extruding and quenching the composition obtained in step (b) to form a sheet, and (d) a method for producing a polymer film comprising stretching the sheet: [Formula 1]

Wherein R is an epoxy, lactam, caprolactam or oxazoline group. The method according to claim 1, wherein the molecular weight of the methacrylate compound represented by the formula (1) is 2,000 to 30,000. The method of claim 1, wherein the inorganic particles have an average particle diameter of 0.1 to 10 µm and at least one selected from the group consisting of titanium compounds, barium sulfide, kaolin, calcium carbonate, silica, and talc. The method of claim 1, wherein the melt kneading step is performed using a compound under the following conditions: 1.Temperature condition (T _i : initial inlet temperature of compounder, T _f : final outlet temperature) 210 ℃ <T _i <250 ℃ T _f = T _i + 40 ° C 2. Residence time in compounder (t) 1 minute 〈t 〈5 minutes 3. Final discharge resin temperature (t) T _f + 5 ° C <T _p <T _f +10 ° C At least one axial stretching is performed in the stretching step, and the stretching conditions are not particularly limited. The method of claim 1, further comprising: (e) applying heat to the surface of the stretched sheet after the stretching step and then heat-setting the dispersion. The method of claim 5, wherein the antistatic material is a quaternary ammonium salt represented by the following formula (2): [Formula 2]

Wherein R ₁ is an alkyl group having 10 to 20 carbon atoms, R ₃ and R ₄ are alkyl groups having less than 5 carbon atoms, R ₂ is a hydrocarbon having a chain structure of less than 4 carbon atoms, and X ⁻ is a counter anion . 6. The method according to claim 5, wherein in step (e), the solid active ingredient is applied to the surface of the film so that 0.01 to 0.1 g / m 2 is present. A polymer film produced by the method of any one of claims 1 to 7. The polymer film of claim 8, wherein the film has a specific gravity of 0.9 to 1.2 g / cm 3 and can be used as a paper substitute substrate.