KR20060094779A - Polyester film having superior conductivity and mechanical quality and its manufacturing process - Google Patents

Abstract

The present invention provides at least a uniaxially oriented polyester film having excellent conductivity and mechanical properties capable of manufacturing a wide range of conductive polyester film and capable of being used as a film for electronic component materials such as displays, touch panels, thermal barriers, and electromagnetic shielding; The present invention relates to a method for producing the same, in which the indium tin oxide nanoparticles having a molecular ratio of 4.0 to 8.0 are coated on one surface of an unstretched film, and 0.01 to 0.1 g / m ² of indium tin oxide active ingredient is present on at least the uniaxially stretched film surface. A non-oriented film manufacturing step (10) of preparing a polyester resin having a predetermined thickness by preparing a polyester resin in chip form and then melt extruding at a temperature of 300 to 320 ° C .; Preparing an indium tin oxide emulsion solution in which an indium chloride and tin chloride are added to the alcohol solvent, followed by stirring to perform a heat treatment; An application step 30 of applying an indium tin oxide emulsion solution having an indium / tin molecular ratio of 4.0 to 8.0 on the surface of the unstretched film; An orientation step 40 of at least uniaxially orientating the unstretched film to which the indium tin oxide emulsion solution is applied at a draw ratio of 1: 1.1 to 1: 5 in a temperature range of 60 to 240 ° C .; Characterized in that is made sequentially.

 Conductivity, mechanical properties, polyester film, conductivity, wide

Description

A polyester film having superior conductivity and mechanical quality and its manufacturing process}

1 is a process chart showing a polyester film production method of the present invention.

 <Brief description of symbols for the main parts of the drawings>

10: unstretched film manufacturing step

20: step of preparing indium tin oxide emulsion solution

30: application step

40: orientation step

The present invention relates to a method for producing at least uniaxially oriented polyester film having excellent conductivity and mechanical properties, and is capable of producing a wide range of conductive polyester film and for electronic component materials such as displays, touch panels, thermal barriers, and electromagnetic shielding. It relates to an at least uniaxially oriented polyester film excellent in conductivity and mechanical properties that can be used as a film, and a method for producing the same.

With the rapid development of the information industry, the demand for films with excellent electrical conductivity and mechanical properties as well as good transparency and printability is increasing. In particular, as the display structure for various uses has been released from the CRT-oriented display structure, demand demands for weight reduction and thinning are increasing, and new material researches that can satisfy the market demand are needed. Display is divided into CRT, PDP (Plasma Display), LCD (Liquid Crystal Display), OELD (Organic Electro Lubrication Display), FLD (Magnetic Emission Display), VFD (Fluorescent Display Tube) and LED (Light Emitting Diode). Display materials are also rapidly changing according to the display market demand for precision. In addition, the demand for touch panel films is increasing as office automation and production process automation proceed.

Excessive solar energy flowing into the car glass or indoor window hurts the skin. In the case of high-density color sunscreens, UV light is easy to block, but there are many problems such as obstructing the view at night or cloudy days. .

In the prior art of manufacturing a film which improves the conductivity of a polyester film, Korean Patent Registration No. 133226 incorporates a sulfonic acid metal salt derivative into a polyester film or applies a quaternary ammonium salt to a surface thereof. Japanese Patent Publication 83-12910 imparted conductivity by containing polyethylene glycol and sulfonic acid derivatives, and Japanese Patent Publication 84-15148 discloses a polyester composition comprising a styrene oligomer and an alkyl sulfonic acid metal salt. In Japanese Patent Publication 93-310975, a conductive polymer was applied to the film surface. However, the above-mentioned conductive technology in the polyester film has a limitation in improving the conductivity, especially the conductive polymer added therein may reduce the polymerization degree of the polyester, thus limiting the amount of use. Since the ammonium salt is mainly used, it can be easily removed by water or a solvent and can be damaged by external friction, so that a long-term conductive effect cannot be obtained.

In order to improve such a problem, application of indium tin oxide having excellent conductivity has been examined and used as a material for electronic parts. In US Pat. Nos. 4,000,346 and 5,607,731, Japanese Patent Laid-Open No. 05-342927, a display was manufactured by applying indium tin oxide or metal oxide particles having similar properties to a glass plate on a glass plate with a thickness of 200 to 2,000 nm. However, when the glass plate is used as a substrate, there is an advantage that the transparency is excellent and the manufacturing process is easy, and there is a limit to easily cracking and reducing the weight by a small external impact. In order to improve these technical limitations, U.S. Patent 5,834,549 fixes organic particles on a polymethyl methacrylate, polyvinyl chloride resin, and polycarbonate film having excellent transparency and fixed conductive particles thereon within a range of 2,000 to 4,000 nm. In Japan Open 60-65036, UV curable resin was applied to polyethylsulfone (PES) or polystyrene (PS) resin, and an indium oxide-based film was formed thereon to produce transparency and a conductive film. In 60-131238, a laminated film composed of a polymer film layer, a polyurethane compound layer, and a layer coated with indium oxide was prepared.

However, when such a polymer material is used as a substrate, the surface tension of the resin is weak and the adhesion to fix the nanoparticles is poor. Therefore, pretreatment with organic materials serving as a binder is difficult. There exists a possibility of bringing about the fall of transparency of a film.

The conductive indium-based particles used in the polymer resin having excellent transparency mainly use a technology synthesized by a conventional sol-gel method as in Japanese Patent Laid-Open No. 6-234521. In this case, coagulation between powders is so severe that uniform transparency and conductivity cannot be expected.

In order to improve the non-uniformity of surface properties that may be caused by such coating, a method of fixing a conductive material on the surface of a substrate by a sputtering method using high pressure, such as Japanese Patent Application Laid-Open No. 5-333329, has also been proposed. Although it is possible to supply conductive layers, existing equipment is expensive and has low productivity and high manufacturing cost because it cannot operate at an average production speed of 10 m / min or more due to the characteristics of the process. In addition, the formation of the conductive film on the oriented film as described above has the advantage of easy manufacturing technology, but there is a limit to the improvement of the productivity and the manufacturing cost is expensive, there is a disadvantage that the production cost increases.

When the conductive material is coated on the non-stretched film and then oriented, the coated conductive material may be cracked to form a space between the conductive materials, thereby causing a problem of poor conductivity. Therefore, a method of making a non-stretched film at least uniaxially in advance to a width and a thickness to be used and then applying a conductive material thereon was used.

However, this method has a problem that it is difficult to manufacture a wide conductive film because the width of the equipment for applying the conductive material solution on the film is limited. In order to manufacture a wide conductive film, it is necessary to manufacture a coating machine suitable for the width, which causes a difficult problem in reality.

The present invention improves these problems and makes it possible to prepare and use a film for an electronic component having excellent conductivity and mechanical properties when at least uniaxially oriented after applying a conductive material on a non-stretched film in advance, and manufacturing a wide conductive polyester film. It is an object of the present invention to provide at least a uniaxially oriented polyester film having excellent conductivity and mechanical properties, and a method for producing the same.

In addition, even when at least uniaxially stretching after applying the indium tin oxide emulsion liquid to produce a wide conductive polyester film, the purpose is not only to lower the conductivity but also to reduce the mechanical properties.

In order to achieve the above object, the present invention applies indium tin oxide nanoparticles having a molecular ratio of 4.0 to 8.0 to one surface of an unstretched film, and at least 0.01 to 0.1 g / m ² of indium tin oxide on the surface of the film uniaxially stretched. A polyester film and polyester resin having at least uniaxially oriented conductivity and mechanical properties characterized by the presence of powder are prepared in the form of chips and then melt-extruded at a temperature of 300 to 320 ° C. to produce a non-stretched polyester having a predetermined thickness. An unstretched film manufacturing step of manufacturing a film; Preparing an indium tin oxide emulsion solution in which an indium chloride and tin chloride are added to the alcoholic solvent, followed by stirring to perform a heat treatment; An indium tin oxide emulsion solution having an indium / tin molecular ratio of 4.0 to 8.0 on the surface of the unstretched film; An orientation step of at least uniaxially aligning the unstretched film to which the indium tin oxide emulsion solution is applied at a draw ratio of 1: 1.1 to 1: 5 in a temperature range of 60 to 240 ° C .; It is characterized in that it is made sequentially, the indium tin oxide is applied to the thickness of 5 to 50 kPa in the coating step, the polyester resin is more than 60% by weight of homo-polyester consisting of ethylene terephthalate, within 40% by weight Diol compounds of diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylene glycol, 1,4-cyclohexanedimethanol and 5-sodium sulfolezocin and It is composed by copolymerizing with the copolymerization component of the polyfunctional dicarboxylic acid, the alcohol solvent of the indium tin oxide emulsion solution preparation step is either isopropyl alcohol or 1,4 butanol, 100 to alcohol 0.8 to 1.0 ml of indium chloride, 0.2 tin tin To 0.5 ml is added and reacted, and heat-treated at a temperature range of 100 to 300 ° C. for 1 to 2 hours at a high pressure of 100 to 120 psi. At least uniaxially oriented polyester film having excellent conductivity and mechanical properties, characterized in that the pH of the mixture is adjusted to 3 to 5 and stirred at a speed of 2000 to 5000 rpm when the tin chloride and the indium chloride are mixed and reacted with alcohol. It provides a manufacturing method.

Among the polyesters, polyethylene terephtalate is stable in chemical properties, excellent in chemical resistance, good mechanical strength, surface properties and thickness uniformity over a wide temperature range from low temperature to high temperature, as well as various applications and process conditions. As it has excellent adaptability to, it is widely used in industrial, medical, magnetic tape, condenser, packaging, photo film and label. Recently, it is widely used for automotive wind film, interior decoration. In addition, as the weight reduction and miniaturization of electronic components are required, the possibility of application to component parts of electronic products, especially display materials, is being actively considered. Polyester is an environmentally friendly resin and has the advantage that little harmful components are generated during combustion.

Hereinafter, the present invention will be described in detail as follows.

The polyester used by this invention 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 terephthalate, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, anthracenedicarboxylic acid and α, β -Bis (2-chlorophenoxy) ethane-4, 4'-dicarboxylic acid, and the like, among which dimethyl terephthalate and terephthalic acid are particularly preferable.

Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, and the like. Of these, ethylene glycol is preferable.

The at least uniaxially oriented polyester film having excellent conductivity and mechanical properties of the present invention is coated with indium tin oxide nanoparticles having a molecular ratio of 4.0 to 8.0 on one surface of the non-stretched film, and at least 0.01 to 0.1 g / on the surface of the film uniaxially stretched. The main composition is such that the m ² indium tin oxide active ingredient is present, and the indium tin oxide nanoparticles are applied to the unstretched polyester film and then oriented so that the indium tin oxide active ingredient is present in the range of 0.01 to 0.1 g / m ² . . If the molecular ratio exceeds the above-mentioned range, the fluidity is lowered and the surface is cracked during stretching.

The method for producing at least uniaxially oriented polyester film having excellent conductivity and mechanical properties according to the present invention is subjected to the following steps.

First, the unstretched film manufacturing step 10 prepares the polyester resin in the form of a chip, and then melt-extrudes at a temperature of 300 to 320 ° C. to produce an unstretched polyester film having a predetermined thickness.

The polyester of the present invention is a homopolyester consisting of at least 60% by weight of ethylene terephthalate and within 40% by weight of diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylene glycol, 1, 4-cyclohexane Diol compounds such as dimethanol and 5-sodium sulfolezocin; It can copolymerize with copolymerization components, such as dicarboxylic acid, such as adipic acid and 5-sodium sulfoisophthalic acid, and polyfunctional dicarboxylic acid, such as trimellitic acid and pyromellitic acid. The polyester resin thus prepared is prepared in the form of a chip, and then melted and extruded at a temperature of 300 to 320 ° C. to produce an unstretched film.

In addition, the indium tin oxide emulsion solution preparation step 20 is performed, and in this step, an indium tin oxide solution, which is a conductive solution applied to an unstretched polyester film, is prepared.

The indium tin oxide emulsion solution is completed by adding an indium chloride and tin chloride to an alcoholic solvent, stirring and reacting, followed by heat treatment.

Indium tin oxide is synthesized using a solvent of alcohols, it is better to use isopropyl alcohol or 1,4 butanol, and indium tin oxide is prepared by reacting an indium compound with a tin compound.

Although it is possible to prepare under ordinary synthetic conditions, it is most preferable to add 0.8-1.0 ml of indium chloride and 0.2-0.5 ml of tin chloride to 100 ml of alcohol for use in the purpose of the present invention.

While the reaction is in progress, the pH of the mixture is adjusted to 3 to 5 and stirred at a speed of 2,000 to 5,000 rpm to maintain a uniform solution. In addition, when the heat treatment is performed at 100 to 300 ° C. for 1 to 2 hours at a high pressure of 100 to 120 psi, an emulsion phase solution containing indium tin oxide particles in an amorphous state can be obtained.

If more than 20% of the surface crystals are formed in the indium tin oxide manufacturing process, not only the adhesion to the film surface is poor, but also the dispersibility and transparency are poor.

Thereafter, the application step 30 is applied to the surface of the unstretched film. An indium tin oxide emulsion solution having an indium / tin molecular ratio of 4.0 to 8.0 is applied.

A solution in which amorphous indium tin oxide particles are synthesized is first applied to the surface of an unstretched polyester film by a conventional coating method, in particular, a gravure roll method or a Meyer bar method.

The surface tension of the polyester film is not less than 39 dyne / cm excellent in adhesion and the coating property of the indium tin oxide emulsion solution prepared by the present invention is not necessary to use a separate binder. When the binder is added and used, discoloration may occur due to side reactions, and in particular, protrusions may occur on the surface of the film due to aggregation.

As can be seen from the experiment, the molecular ratio of indium / tin of the indium tin compound coated on the unstretched film is most suitable. When the indium / tin molecule ratio is less than 4.0, the conductivity is inferior and cannot be used as an electronic component material film. When it is more than 8.0, the manufacturing cost is too high compared to the conductivity improvement effect.

If it is out of the above-described range, the flowability of the indium tin oxide nanoparticles are inferior, and when the non-stretched film is stretched, the coated indium tin oxide nanoparticles are divided and the conductivity is degraded.

Finally, the alignment step 40 is performed, wherein the oriented conditions are at least uniaxially oriented to the unstretched film coated with the indium tin oxide emulsion solution at a draw ratio of 1: 1.1 to 1: 5 in a temperature range of 60 to 240 ° C. Let's do it.

The polyester unstretched film to which the indium tin oxide is first applied is uniaxially oriented at a draw ratio of 1: 1.1 to 1: 5 at a temperature range of 60 to 240 ° C. to induce 0.01 to 0.1 g / m 2 of indium tin on the surface of the film. It is desirable to have an oxide active ingredient present and to apply a thickness of 5 to 50 GPa.

If the indium tin oxide active ingredient is 0.01 g / m ² or less, the conductivity becomes low and it cannot be used as an electronic component film. If it is 0.1 g / m ² or more, the surface hardness becomes excessively high, causing local splitting and a large variation in coating thickness. There is concern.

In addition, there is a fear that the light transmittance decreases and the haze increases. If the thickness of the coating layer is 5 kPa or less, the conductivity becomes poor and the uncoated portion is likely to occur, and there is a possibility that the coating layer may easily fall off even with a small external impact. If it is 50 kPa or more, a lot of drying time is required, and in the previous process, it is difficult to raise the indium tin coating layer on the unstretched film too thick.

The longer the drying time, the higher the energy cost, the higher the hardness of the coated surface may cause partial cracking of the surface and, in severe cases, breakage during the orientation process. In addition, when the draw ratio is less than 1: 1.1, the mechanical properties are inferior, and when the draw ratio is oriented at a high draw ratio of 1: 5 or more, crystals are excessively oriented in one direction, causing breakage that is easily torn by a small external force.

In the above-described manufacturing method, the thickness of the indium tin oxide solution applied in the applying step 30 should be determined by the ratio oriented in the alignment step 40.

The polyester film made of the above-mentioned steps was made to have a strength of 10 to 50 kg / ㎜ in the film thickness range of 5 to 200 ㎛ and the surface resistance is 10 ³ Ω · cm or less, excellent in conductivity and mechanical properties. It could be used as a film for electronic component materials such as displays, touch panels, thermal barriers, and electromagnetic shielding.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto, and various performance evaluations of the films prepared in Examples and Comparative Examples of the present invention were performed by the following methods.

(1) transparency

Transparency was measured by haze and light transmittance. The measuring instrument was a haze meter (Motel name: SEP-H) manufactured by Seimitsu Kogaku Co., Ltd., Japan, and measured the incident light and scattered light using a C-light source.

Haze = scattered light / (scattered light + transmitted light)

(2) conductivity

The conductivity was determined by the surface resistance value, and the insulation resistance meter of the US Hewlett-Packard company was used. It measured on the conditions of 23 degreeC, 60% of relative humidity, and 500V of applied voltages.

(3) breaking strength

The breaking strength of the film was measured by ASTM D 882 using Instron.

(Example 1)

After mixing dimethyl terephthalate and ethylene glycol in an equivalent ratio of 1: 2 and adding a yester exchange reaction catalyst to produce a lollyethylene terephthalate monomer (bis-2-hydroxyethyl terephthalate), a conventional polycondensation catalyst The polycondensation reaction was completed to prepare a polyester resin chip having an ultimate viscosity of 0.760 dl / g, a glass transition point of 65 ° C., and a crystallization temperature of 130 ° C. A non-oriented film having a thickness of 144 μm was prepared using this chip. Indium tin oxide was applied to one side of the film.

Indium tin oxide used at this time was added 0.8 ml of indium chloride and 0.5 ml of tin chloride to 100 ml of isopropyl alcohol at pH 3, and synthesized at 150 psi for 1 hour at a pressure of 100 psi. The composition ratio of indium / tin was 4.8 Phosphorus emulsion solution was obtained.

This solution was applied to the surface of the film by a Mayer coating method.

The applied film was sequentially oriented at 85 ° C. under draw ratio conditions of machine direction (MD) 1: 3 and width direction (TD) 1: 4 times, respectively, to prepare a 12 μm biaxially oriented polyester film.

The active ingredient of indium tin oxide applied to the final film was 0.09 g / m 2 and the coating thickness was 35 mm 3. The light transmittance was 90%, the haze was 23, the transparency was excellent, and the surface resistance was 10 ³ Ω · cm, and the conductivity was very good. The breaking strength was 25 kg / mm2 in the machine direction (MD) and 23 kg / mm2 in the width direction (TD). The mechanical properties were very good, and the surface condition was good.

(Examples 2 to 5 and Comparative Examples 1 to 5)

In the same manner as in Example 1, using the polyethylene terephthalate film as a substrate, the synthesis conditions, coating and film orientation conditions of the indium tin oxide was prepared as shown in Table 1 below, to prepare a film for electronic component material and compare the physical properties did.

Condition  Film thickness (㎛) Indium / Tin Composition Active ingredient (g / m ² ) Coating thickness (Å) Light transmittance (%)  Haze (%)  Surface resistance (Ωcm)  Elongation Ratio (MD / TD) Breaking Strength (MD / TD) (kg / mm ² ) Example 1 12 4.8 0.09 35 90 2.1 10 ³ 1: 3/1: 4 25/23 Example 2 50 4.6 0.05 41 89 2.5 10 ² 1: 4/1: 1 13/11 Example 3 180 7.1 0.03 35 88 2.7 10 ² 1: 3/1: 3 11/12 Example 4 20 5.1 0.06 31 90 2.2 10 ³ 1: 3/1: 1 18/11 Example 5 8 6.0 0.08 15 90 2.5 10 ² 1: 5/1: 4 32/29 Comparative Example 1 25 1.2 0.03 31 90 2.3 10 ² 1: 1/1: 1 9/3 Comparative Example 2 120 4.6 0.06 25 83 3.3 10 ² 1: 1/1: 1 9/6 Comparative Example 3 12 3.9 0.005 20 90 2.2 10 ² 1: 3/1: 4 21/16 Comparative Example 4 20 5.2 0.3 25 80 3.5 10 ² 1: 7/1: 4 Breaking Comparative Example 5 15 6.1 0.05 86 85 3.6 10 ² 1: 5/1: 4 Breaking

As shown in the above table, when the indium tin component ratio is in the range of 4.0 to 8.0, the mechanical properties and conductivity are most excellent, and the orientation ratio is preferably between 1: 1.1 and 1: 5 when oriented.

The polyester film produced by the present invention has a strength of 10 to 50 kg / mm ² in the film thickness range of 5 to 200 ㎛, the surface resistance is 10 ³ Ω · cm or less, excellent in conductivity and mechanical properties have.

In addition, since indium tin oxide is applied to the film in the unstretched state, the film can be stretched after coating to produce a film having a wide width in which conductivity is not lowered.

Claims (6)

Indium tin oxide nanoparticles having a molecular ratio of 4.0 to 8.0 are coated on one surface of the unstretched film, and at least uniaxially oriented, characterized in that an indium tin oxide active ingredient of 0.01 to 0.1 g / m ² exists on the surface of the film uniaxially stretched. Polyester film with excellent conductivity and mechanical properties. A non-stretched film manufacturing step 10 of preparing a polyester resin having a predetermined thickness by manufacturing a polyester resin in chip form and then melt extruding at a temperature of 300 to 320 ° C .; Preparing an indium tin oxide emulsion solution in which an indium chloride and tin chloride are added to the alcohol solvent, followed by stirring to perform a heat treatment; An application step 30 of applying an indium tin oxide emulsion solution having an indium / tin molecular ratio of 4.0 to 8.0 on the surface of the unstretched film; An orientation step 40 of at least uniaxially orientating the unstretched film to which the indium tin oxide emulsion solution is applied at a draw ratio of 1: 1.1 to 1: 5 in a temperature range of 60 to 240 ° C .; At least uniaxially oriented polyester film manufacturing method excellent in the conductivity and mechanical properties, characterized in that is made sequentially. The method of claim 2, wherein indium tin oxide is applied in a coating step (30) to a thickness of 5 to 50 kPa. The polyester resin of claim 2, wherein the polyester resin is a homopolyester composed of at least 60% by weight of ethylene terephthalate, and within 40% by weight of diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylene glycol, 1 The electroconductivity and mechanical properties are characterized by copolymerizing with a copolymer of a diol compound of 4-cyclohexanedimethanol and 5-sodium sulfolezocin and a polyfunctional dicarboxylic acid of dicarboxylic acid, trimellitic acid and pyromellitic acid. Excellent method for producing at least uniaxially oriented polyester film. The alcohol solvent of the step 20 of preparing the indium tin oxide emulsion solution is either isopropyl alcohol or 1,4butanol, and 0.8 to 1.0 ml of indium chloride and 0.2 to 0.5 ml of tin chloride are added to 100 ml of alcohol. At least uniaxially oriented polyester film having excellent conductivity and mechanical properties, characterized in that heat treatment is carried out at a high temperature of 100 to 120 psi for 1 to 2 hours in a temperature range of 100 to 300 ° C. 6. The electroconductive and mechanical properties according to claim 2 or 5, wherein when the tin chloride and indium chloride are mixed with the alcohol and reacted, the pH of the mixture is adjusted to 3-5 and stirred at a speed of 2000 to 5000 rpm. This excellent at least uniaxially oriented polyester film production method.

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