KR20150077745A - Polyester film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an antistatic polyester film and, specifically, to a polyester film, which is coated with a conductive polymer antistatic agent for packaging, processing an electronic material, and protecting a product, and has a surface resistance lower than the existing polyester film, and to a manufacturing method thereof. A polyester film comprises: a substrate layer comprising a polyester resin; and an antistatic layer stacked on one side or both sides of the substrate layer.

Description

[0001] POLYESTER FILM AND MANUFACTURING METHOD THEREOF [0002]

The present invention relates to an antistatic polyester film, and relates to a polyester film coated with a conductive polymeric antistatic agent on packaging, electronic material processing, and product protection, which has lower surface resistance than conventional polyester films, and a method for producing the same.

The antistatic polyester film produced by the production method of the present invention is useful as a film for a process or a protective film because it is improved in resistance to moisture or a solvent.

Recently, due to the rapid development of various electronic, electrical and information communication fields, there have been problems caused by static electricity in many fields ranging from industrial appliances and household appliances to which they have been applied, and antistatic functions in these devices and on the spot have become essential functions . Antistatic means discharging the charge accumulated on the surface of the insulator by an appropriate method. Such antistatic property is required because static electricity is generated in the film manufacturing process or film processing process to adhere dust or foreign matter to the product and cause a discharge phenomenon, which causes a risk of flammability when an organic solvent is used. Therefore, it is an essential requirement to provide antistatic performance.

In order to impart such an antistatic property, an antistatic layer is formed on the film. When the crosslinking density of the binder resin used for forming the antistatic layer is low, the coating film is damaged by the solvent used in the subsequent (post) There is a possibility. Therefore, there has been a study to improve the solvent resistance of the binder resin forming the antistatic layer.

Korean Patent No. 10-0902033 (2009.06.03)

An object of the present invention is to provide a polyester film having an antistatic coating layer which is improved in resistance to moisture or a solvent and has excellent surface resistance, and a process for producing the polyester film. That is, a polyester film having a low swelling ratio and a high gel fraction of an antistatic layer and a method for producing the polyester film are provided.

In order to achieve the above object, the present invention is as follows.

The present invention relates to a polyester film comprising a substrate layer made of a polyester resin and an antistatic layer laminated on one side or both sides of the base layer,

Wherein the antistatic layer comprises a water dispersible polyurethane resin consisting of 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups or a branched polymer having 3 or more terminal groups, The present invention relates to a polyester film formed by coating and drying an aqueous coating composition comprising a conductive polymer resin selected from polythiophenes or polythiophene derivatives and water.

Also,

a) melt-extruding a polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups on one side or both sides of the machine direction-stretched polyester film, A water-dispersible polyurethane resin, a conductive polymer resin selected from a polythiophene or a polythiophene derivative, and water, and then stretching in the transverse direction; And

d) opening and fixing the biaxially stretched polyester film;

To a process for producing a polyester film.

The polyester film according to the present invention has an antistatic property on the coated surface and has an effect of preventing stacking due to static electricity between films during off-sheet operation and preventing problems caused by static electricity in the applied product.

In addition, the antistatic layer has excellent antistatic properties and solvent resistance, has an adhesive strength to a tape, printability, and one side of a substrate layer on which an antistatic layer is not formed has adhesiveness and printability. Particularly, the solvent resistance to solvents such as n-hexane, toluene, and ethyl acetate is very excellent, so that the solvent can be freely selected in a subsequent step.

One aspect of the present invention is a polyester film comprising a substrate layer made of a polyester resin and an antistatic layer laminated on one surface or both surfaces of the substrate layer, wherein the antistatic layer comprises 10 to 75% by weight of a linear polymer having two terminal groups, And 25 to 90% by weight of a branched polymer having three or more terminal groups, or a water-dispersible polyurethane resin consisting of a branched polymer having three or more terminal groups, a conductive polymer resin selected from polythiophenes or polythiophene derivatives, and Wherein the water-based coating composition is formed by coating and drying a water-based coating composition.

In one embodiment of the present invention, the antistatic layer may have a surface resistance of 10 ⁵ to 10 ⁹ Ω / sq.

In one embodiment of the present invention, the water-based coating composition may further comprise any one or two or more additives selected from a wetting agent, an alcohol-based solvent, a particle, a slip agent, a crosslinking agent, and a hardener.

In one embodiment of the present invention, the coating composition comprises 0.1 to 10 wt% of a water dispersible polyurethane resin, 0.1 to 10 wt% of a conductive polymer resin, 0.1 to 1 wt% of a wetting agent, 0.1 to 10 wt% of an alcoholic solvent, 0.1 To 10% by weight and the balance of 100% by weight.

In one embodiment of the present invention, the terminal group may be an isocyanate group in which some or all of the terminal groups are blocked with an inorganic acid base.

In one embodiment of the present invention, the water dispersible polyurethane resin is prepared by reacting 39 to 45% by weight of a polyol, 0.3 to 1.2% by weight of trimethylolpropane and 50 to 57% by weight of an isocyanate compound to prepare a prepolymer having isocyanate as an end group , And then reacting the salt of an inorganic acid with 3 to 4% by weight to block the ionic group at the end of the isocyanate.

In one embodiment of the present invention, the water dispersible polyurethane resin may have a weight average molecular weight of 10,000 to 20,000.

In one embodiment of the present invention, the antistatic layer may be coated by an in-line coating method.

In one embodiment of the present invention, the antistatic layer may have a dry coating thickness of 10 to 500 nm.

In one embodiment of the present invention, the polyester film may have a total thickness of 12 to 250 mu m.

Further, the present invention relates to a method for producing a polyester film,

a) melt-extruding a polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups on one side or both sides of the machine direction-stretched polyester film, A water-dispersible polyurethane resin, a conductive polymer resin selected from a polythiophene or a polythiophene derivative, and water, and then stretching in the transverse direction; And

d) opening and fixing the biaxially stretched polyester film;

. ≪ / RTI >

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

The present invention is characterized in that an antistatic layer for imparting antistatic properties to one side or both sides of a polyester film is formed by an in-line coating method.

In the case of forming the antistatic layer on the polyester film by applying it off-line, there is a problem in that the cost is increased because the process is further increased, and the cost is increased as compared with the in-line coating method because the coating thickness is increased. Therefore, the present inventors have found that the application of the water-based coating composition for forming the antistatic layer, which is applied by the in-line coating method and dried and cured in the stretching process, makes the coating thickness thin and the adhesive strength to the polyester film is excellent, It is characterized by excellent resistance to moisture and solvents.

In the present invention, the base layer may be a film made of a polyester resin, more specifically polyethylene terephthalate or polyethylene naphthalate. More preferably, polyethylene terephthalate having an intrinsic viscosity in the range of 0.6 to 0.7 is used because it is excellent in weather resistance and hydrolysis resistance. The polyester film having a thickness of 12 to 300 mu m is preferable because it is advantageous in production and can realize various laminated structures.

The opposite surface of the polyester film as the substrate layer on which the antistatic coating layer is formed may be subjected to corona treatment to impart printability.

In the present invention, the antistatic layer preferably comprises 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups, or a water-dispersible poly A conductive polymer resin selected from a urethane resin, a polythiophene or a polythiophene derivative, and water, and is coated by an in-line coating method.

Further, if necessary, the water-based coating composition may further include any one or two or more additives selected from a wetting agent, an alcohol-based solvent, a particle, a slip agent, a crosslinking agent, and a curing agent.

In order to enable in-line coating, a water-based composition should be used. In the case of an aqueous composition, durability of water or a solvent is weakened in a post-process. However, the inventors of the present invention have found that mixing a specific water-dispersible polyurethane resin with a conductive polymer The present inventors have found that the antistatic coating layer formed is excellent in physical properties and has excellent water resistance and durability so that it can exhibit physical properties equal to or higher than those of conventional offline coatings.

The antistatic layer may have a dry coating thickness of 10 to 500 nm and a surface resistance of 10 ⁵ to 10 ⁹ Ω / sq. If the dry coating thickness is less than 10 nm, the surface resistance may be high, and if it exceeds 500 nm, the cost may increase, and the viscosity may increase and the processability may be deteriorated. And is suitable for application as a substrate film such as an ITO process in a range of surface resistivity of 10 ⁵ to 10 ⁹ Ω / sq.

More specifically, the water-based coating composition comprises 0.1 to 10 wt% of a water-dispersible polyurethane resin, 0.1 to 10 wt% of a conductive polymer resin, 0.1 to 1 wt% of a wetting agent, 0.1 to 10 wt% of an alcoholic solvent, By weight, and the balance of 100% by weight.

The water-dispersible polyurethane resin has three or more isocyanate functional groups, which are terminal groups, and a part or all of the isocyanate groups are blocked with an inorganic acid base, more specifically, a branched polymer blocked with an inorganic salt such as sulfate, A linear polymer in which two or more isocyanate functional groups are blocked and part or all of the isocyanate groups are blocked with an inorganic acid base and more specifically blocked with an inorganic salt such as sulfate.

The water-dispersible polyurethane resin is composed of 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups or 100% by weight of a branched polymer having 3 or more terminal groups Lt; / RTI > By using such a resin, crosslinking density is improved and solvent resistance is improved.

When the content of the branched polymer is less than 25% by weight, the intended degree of swelling and gel fraction in the present invention can not be satisfied, and it may be difficult to obtain a coating film excellent in adhesion under high temperature and high humidity. In the present invention, the branched polymer means a resin having three or more isocyanate functional groups.

As a method for producing the water-dispersible polyurethane resin, for example, a prepolymer having isocyanate as a terminal group is prepared by reacting 39 to 45% by weight of a polyol, 0.3 to 1.2% by weight of trimethylolpropane and 50 to 57% by weight of an isocyanate compound And then reacting the salt with 3 to 4% by weight of an inorganic acid salt to block the ionic group of the sulfate at the end of the isocyanate.

In addition, it is preferable that a coating film having a weight average molecular weight of 10,000 to 20,000 is not gelated and a water-dispersible, coating film having excellent physical properties at high temperature and high humidity can be obtained.

The weight average molecular weight can be measured using a GPC-MALS (Multi Angle Light Scattering) system (Wyatt). The MALS system has the following structure.

MALS System Configuration

- GPC; Water 1525 Binary HPLC Pump

- RI detector; Optilab rex

- MALS; Wyatt Dawn 8+

- Column; PLgel 5 占 퐉 Mixed-C (7.5 mm? 300 mm) 占 2 (Polymer Laboratories)

- mobile phase: DMF (50 mM LiCl)

- Flow rate: 0.5 mL / min

- Temperature: 50 ℃

- Injection volume: 0.5%, 500 μ

The polyol may be a polyester-based polyol or a polyether-based polyol, and preferably a polyester-based polyol. The polyester-based polyol is a polyol produced from the reaction of a carboxylic acid, sebacic acid, or acid anhydride with a polyhydric alcohol. The kind of the polyol is not limited, and it is preferable to use a polyester polyol having a weight average molecular weight of 600 to 3000. Polyester-based polyols include polyols prepared from the reaction of carboxylic acids, sebacic acids, or acid anhydrides with polyhydric alcohols. The kind of the polyol is not limited, and it is preferable to use a polyester polyol having a weight average molecular weight of 600 to 3000. The content thereof is preferably 39 to 45% by weight. If it is used in an amount less than 39% by weight, the molecular weight will be small, the primer layer will become too hard, the stretching will be difficult and the appearance of the coating will not be excellent. If it exceeds 45% by weight, the ILC layer will become too soft, .

The trimethylolpropane is used for producing a prepolymer having three functional groups, and it is preferable to use 0.3 to 1.2% by weight. If it is used in an amount less than 0.3% by weight, the crosslinking density may be lowered and anti-blocking may be deteriorated. When the amount is more than 1.2% by weight, the crosslinking density becomes excessively high, Is not excellent, and adhesion may be deteriorated.

The isocyanate compound is not limited, but hexamethylene diisocyanate is preferably used. It is possible to prepare a prepolymer having three functional groups within the range of 50 to 57% by weight.

The inorganic acid salt is preferably sodium hydrogen sulfate, and its content is preferably 3 to 4% by weight.

The water-dispersible polyurethane resin is preferably used in an amount of 0.1 to 10% by weight based on the total weight of the water-based coating composition. When the water-dispersible polyurethane resin is used in an amount of less than 0.1% by weight, adhesion of an aqueous dispersion containing a polythiophene or a polythiophene derivative In case of using more than 10% by weight, surface resistance may not be obtained after stretching.

The conductive polymer resin is used for imparting antistatic properties, and may include a polythiophene or a polythiophene derivative. More preferably, an aqueous dispersion of a polyanion and a polythiophene or an aqueous dispersion of a polyanion and a polythiophene derivative can be used. The polyanion is an acidic polymer, such as a polymeric carboxylic acid or a polymeric sulfonic acid, or polyvinylsulfonic acid. Examples of the polymeric carboxylic acid include polyacrylic acid, polymethacrylic acid and the like. Polymeric sulfonic acids include polystyrene sulfonic acid and the like. The amount of the polyanion is preferably greater than 1% by weight based on 1% by weight of the polythiophene or polythiophene derivative, more preferably, less than 1% by weight of the polythiophene or polythiophene derivative. By weight or less is preferable. The conductive polymer resin is preferably used in an amount of 0.1 to 10% by weight based on the total weight of the water-based coating composition. If the conductive polymer resin is less than 0.1% by weight, the surface resistance may be high. So that the antistatic layer having the best antistatic property in the above range can be formed.

It is most preferable that the mixing ratio of the polyurethane resin to the water dispersant or polythiophene derivative containing polythiophene is 50 to 150% by weight. When the mixing ratio is less than 50% by weight, surface resistance may not be obtained. If it is more than 150% by weight, adhesion of the polythiophene-containing water dispersant or polythiophene derivative may be weakened and desorbed.

The wetting agent used for uniformly spreading the emulsion on the polyester film is selected from polyethylene glycol, polyethylene ester, modified silicone, fluorine mixture and the like, and it is preferable that the wetting agent is 0.1 By weight to 0.5% by weight is preferable because of excellent adhesiveness.

Specific examples thereof include isopropyl alcohol, ethyl cellosolve, methylcellosolve, butyl cellosolve and the like. The alcohol solvent is used in an amount of 0.1 to 10% by weight, Is preferred for reasons of coating properties and processability.

The crosslinking agent is used for improving the solvent resistance. Specifically, for example, any one or more compounds selected from the group consisting of block isocyanate type, carbodiimide type, oxazoline type, epoxy type and melamine type can be used . The content is preferably 0.1 to 10% by weight, more preferably 0.1 to 0.5% by weight. If it is used in an amount less than 0.1% by weight, the solvent resistance may be lowered, and when it is used in an amount exceeding 10% by weight, surface resistance may not be obtained.

If necessary, particles can be added to improve the blocking property of the coating layer using an emulsion, and inorganic particles, organic particles and the like can be added. The content thereof is preferably 0.01 to 10% by weight.

In addition, additives such as a UV stabilizer, a slip agent, and a hardener, which are conventionally used in the field, can be further added as needed.

In addition,

a) melt-extruding a polyester resin to produce a polyester sheet;

b) stretching the polyester sheet in the machine direction;

c) 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups on one side or both sides of the machine direction-stretched polyester film, A water-dispersible polyurethane resin, a conductive polymer resin selected from a polythiophene or a polythiophene derivative, and water, and then stretching in the transverse direction; And

d) opening and fixing the biaxially stretched polyester film;

To a process for producing a polyester film.

Further, the method may further comprise a step of coating a polyacrylic resin or a polyurethane resin on the opposite side of the polyester film on which the antistatic layer is formed after the step c), if necessary, or after the step d) And a step of corona treating the surface of the substrate. When the polyacrylic resin or the polyurethane resin is coated as described above, the adhesiveness and the printability can be further improved, and it may be formed by an in-line coating method. The coating thickness is preferably 50 to 150 nm in the dry coating thickness.

The corona treatment is intended to further improve printability, and the corona treatment is not limited as long as it is customary in the art.

In the step a), a resin is melt-extruded in a cylinder to produce a polyester film.

The step b) is preferably a process for producing a polyester film by biaxially stretching a polyester sheet, and the machine direction stretching is preferably performed by using one or more rollers.

Next, in step c), an antistatic layer is formed by an in-line coating method, and it is preferable to use an emulsion that is water-dispersible so that it can be used for in-line coating. At this time, the composition of the coating composition for forming the antistatic layer is as described above, and it is preferable that the coating composition is applied so that the thickness of the dried coating after stretching upon application becomes 10 to 500 nm. After the antistatic layer is formed by applying the coating composition, the film is stretched in the transverse direction. At this time, it is preferable to use a tenter for the transverse drawing.

Next, the water used for the antistatic layer is removed, the antistatic layer is cured, and the film is dried and heat-set to prevent the film from shrinking.

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

The physical properties of the present invention were measured as follows.

1) Surface resistance

The surface resistance of the antistatic layer of the present invention was evaluated. The measurement method is described in Mitsubishi Chemical Corp. The surface resistivity was measured using a Hiresta-Up MCP-HP450 instrument at 25 ° C, 50% RH, 10 V (or 100 V) for 10 seconds.

2) Solvent resistance

The antistatic property of the antistatic layer of the present invention was evaluated. The measurement method was to measure the solvent resistance by rubbing 10 times with a metal plate of 25 mm x 25 mm in width and 915 g in weight on a microfiber cloth impregnated with isopropyl alcohol, ethyl alcohol, normal hexane, toluene and ethyl acetate. The state of the coated surface was evaluated according to the following criteria.

&Amp; cir &: When there is almost no change in antistatic property and there is no degree of scrubbing on the microfiber cloth

O: When there is almost no change in antistatic property and the degree of scrubbing on the microfiber cloth is small

△: Change in antistatic property is less than 10 ² Ω / sq, and the degree of scrubbing on the microfiber cloth is about ~

X: When the antistatic property is lost or the degree of scrubbing on the microfiber cloth is severe

3) Measurement of Physical Properties of Coating Film Using Coating Composition

Water-dispersible polyurethane 15 g of the conductive polymer binder applied is placed in a bowl with a diameter of 80 mm and a height of 15 mm and dried at 65 ° C for 72 hours and at 120 ° C for 3 hours. 1 g of the dried film was immersed in 50 g of distilled water and allowed to stand at 70 ° C for 24 hours. Take out the coated film and measure the swelling ratio. The dried film was dried at 120 ° C for 3 hours, and the weight was recorded to measure the gel fraction.

A. Swelling Ratio: About 1 g of dry film is immersed in 50 g of distilled water and left at 70 ° C for 24 hours. Take out the coated film and record the weight.

Swelling Ratio = (Initial weight) / Initial weight * 100

N. Gel Fraction: After leaving the dried film at 120 ℃ for 3 hours, record the weight.

Gel Fraction = (weight after drying / initial weight) * 100

[Production Example 1]

Preparation of Water-dispersible Polyurethane Binder (1) and Preparation of Conductive Polymer Mixture

The water-dispersed polyurethane having a theoretical linear polymer content of 100% by weight was prepared.

40% by weight of polyol (Polyethyleneadipate Diol) and 58% by weight of hexamethylene diisocyanate were reacted to prepare a prepolymer having an isocyanate functional group as a terminal group, and then sodium hydrogen sulfate 2% by weight of isocyanate was reacted with isocyanate, which is a terminal functional group of the prepolymer, to prepare a polyurethane having an ionic group and having a weight average molecular weight of 8,000. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane binder (1) having a solid content of 20% by weight. The water-dispersible binder thus prepared was blended with a conductive polymer resin (SY-CP-E421A, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Production Example 2]

Preparation of Water-dispersible Polyurethane Binder (1) and Preparation of Conductive Polymer Mixture

The water-dispersed polyurethane having a theoretical linear polymer content of 100% by weight was prepared.

40% by weight of polyol (Polyethyleneadipate Diol) and 58% by weight of hexamethylene diisocyanate were reacted to prepare a prepolymer having an isocyanate functional group as a terminal group, and then sodium hydrogen sulfate 2% by weight of isocyanate was reacted with isocyanate, which is a terminal functional group of the prepolymer, to prepare a polyurethane having an ionic group and having a weight average molecular weight of 8,000. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane binder (1) having a solid content of 20% by weight. The resulting water-dispersible binder was blended with a conductive polymer resin (SY-CP-E421M, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Production Example 3]

Preparation of Water-dispersible Polyurethane Binder (2) and Preparation of Conductive Polymer Mixture

Theoretically, a water-dispersed polyurethane having a linear polymer content of 50% by weight and a branched polymer content of 50% by weight was prepared.

A prepolymer having an isocyanate functional group as a terminal group was prepared by reacting 40 wt% of polyol (Polyethyleneadipate Diol), 0.6 wt% of trimethylol propane, and 55.9 wt% of hexamethylene diisocyanate, 3.5% by weight of sodium hydrogen sulfate as an ionic group was reacted with an isocyanate as a terminal functional group of the prepolymer to prepare a polyurethane having an ionic group and having a weight average molecular weight of 14,400. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane (2) having a solid content of 20% by weight. The water-dispersible binder thus prepared was blended with a conductive polymer resin (SY-CP-E421A, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Production Example 4]

Preparation of Water-dispersible Polyurethane Binder (2) and Preparation of Conductive Polymer Mixture

Theoretically, a water-dispersed polyurethane having a linear polymer content of 50% by weight and a branched polymer content of 50% by weight was prepared.

A prepolymer having an isocyanate functional group as a terminal group was prepared by reacting 40 wt% of polyol (Polyethyleneadipate Diol), 0.6 wt% of trimethylol propane, and 55.9 wt% of hexamethylene diisocyanate, 3.5% by weight of sodium hydrogen sulfate as an ionic group was reacted with an isocyanate as a terminal functional group of the prepolymer to prepare a polyurethane having an ionic group and having a weight average molecular weight of 14,400. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane (2) having a solid content of 20% by weight. The resulting water-dispersible binder was blended with a conductive polymer resin (SY-CP-E421M, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Production Example 5]

Preparation of Water-dispersible Polyurethane Binder (3) and Preparation of Conductive Polymer Mixture

Theoretically, a water-dispersed polyurethane having a content of the branched polymer of 100% by weight was prepared.

A prepolymer having an isocyanate functional group as a terminal group was prepared by reacting 40 wt% of polyol (Polyethyleneadipate Diol), 1.2 wt% of trimethylol propane, and 54.8 wt% of hexamethylene diisocyanate, 4.0% by weight of sodium hydrogen sulfate as an ionic group was reacted with an isocyanate as a terminal functional group of the prepolymer to prepare a polyurethane having an ionic group and having a weight average molecular weight of 19,000. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane having a solid content of 20% by weight. The water-dispersible binder thus prepared was blended with a conductive polymer resin (SY-CP-E421A, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Production Example 6]

Preparation of Water-dispersible Polyurethane Binder (3) and Preparation of Conductive Polymer Mixture

Theoretically, a water-dispersed polyurethane having a content of the branched polymer of 100% by weight was prepared.

A prepolymer having an isocyanate functional group as a terminal group was prepared by reacting 40 wt% of polyol (Polyethyleneadipate Diol), 1.2 wt% of trimethylol propane, and 54.8 wt% of hexamethylene diisocyanate, 4.0% by weight of sodium hydrogen sulfate as an ionic group was reacted with an isocyanate as a terminal functional group of the prepolymer to prepare a polyurethane having an ionic group and having a weight average molecular weight of 19,000. 20% by weight of the polyurethane thus prepared was dispersed in 80% by weight of water to prepare a water-dispersible polyurethane having a solid content of 20% by weight. The resulting water-dispersible binder was blended with a conductive polymer resin (SY-CP-E421M, available from Suyang Chemtech Co., Ltd.) at a weight ratio of 30:70 to prepare a mixed solution.

[Example 1]

Preparation of coating composition (1)

(Coating composition) was prepared by mixing 15% by weight of the mixed liquid of Preparation Example 3, 0.4% by weight of a wetting agent (Zonyl FSH from DuPont), 5% by weight of isopropyl alcohol and 0.2% by weight of a crosslinking agent (Trixene BI 7987, Baxenden) (1).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Thereafter, the coating composition (1) was coated on one side by a bar coating method, preheated at 140 ° C, and dried, and then stretched 3.5 times in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Example 2]

Preparation of Coating Composition (2)

(Coating composition) was prepared by mixing 15% by weight of the mixed liquid of Production Example 4, 0.4% by weight of a wetting agent (Zonyl FSH from DuPont), 5% by weight of isopropyl alcohol and 0.2% by weight of a crosslinking agent (Trixene BI 7987 from Baxenden) (2).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Then, the coating composition (2) was coated on one side by a bar coating method, and then preheated at 140 ° C, dried and stretched 3.5 times in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Example 3]

Preparation of Coating Composition (3)

15% by weight of the mixed liquid of Production Example 5, 0.4% by weight of a wetting agent (Du Pont's Zonyl FSH), 5% by weight of isopropyl alcohol, and 0.2% by weight of a crosslinking agent (Trixene BI 7987 from Baxenden) (3).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Thereafter, the coating composition (3) was coated on one side by a bar coating method and then preheated at 140 ° C, dried and stretched 3.5 times in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Example 4]

Preparation of coating composition (4)

(Coating composition) was prepared by mixing 15% by weight of the mixed liquid of Preparation Example 6, 0.4% by weight of a wetting agent (Zonyl FSH from DuPont), 5% by weight of isopropyl alcohol and 0.2% by weight of a crosslinking agent (Trixene BI 7987, Baxenden) (4).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Then, the coating composition (4) was coated on one side by a bar coating method, followed by preheating at 140 ° C, followed by drying and 3.5 times stretching in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Comparative Example 1]

Preparation of coating composition (5)

15% by weight of the mixed liquid of Preparation Example 1, 0.4% by weight of a wetting agent (Zonyl FSH from DuPont), 5% by weight of isopropyl alcohol and 0.2% by weight of a crosslinking agent (Trixene BI 7987 from Baxenden) (5).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Then, the coating composition 5 was coated on one side by a bar coating method and then preheated at 140 ° C, dried and stretched 3.5 times in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Comparative Example 2]

Preparation of Coating Composition (6)

15% by weight of the mixed liquid of Production Example 2, 0.4% by weight of a wetting agent (Zonyl FSH from DuPont), 5% by weight of isopropyl alcohol and 0.2% by weight of a crosslinking agent (Trixene BI 7987 from Baxenden) (6).

Production of polyester film for back sheet

The polyethylene terephthalate chip having a water content of less than 100 ppm was injected into a melt extruder and melted. The extruded product was rapidly cooled and solidified by a casting drum having a surface temperature of 20 캜 to prepare a polyethylene terephthalate sheet having a thickness of 2000 탆 .

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 110 ° C and then cooled to room temperature. Thereafter, the coating composition 6 was coated on one side by a bar coating method, preheated at 140 ° C, and dried, and then stretched 3.5 times in the transverse direction (TD). Thereafter, the film was heat-treated at 235 DEG C in a 5-stage tenter, relaxed 10% in the machine direction and transverse direction at 200 DEG C, and heat set to prepare a 100 mu m biaxially oriented film having an antistatic layer on one surface. The antistatic layer had a dry coating thickness after stretching of 75 nm.

The physical properties of the thus obtained film are shown in Table 1 below.

[Table 1]

As shown in the above table, it can be seen that the swelling ratio of the antistatic agent containing the antistatic layer according to the present invention is low and the higher the gel fraction, the higher the solvent resistance to normal hexane, toluene and ethyl acetate. When the antistatic agent having the impurity ion removed was used, it was found that the surface resistance was higher than that of the antistatic agent without the removal of the impurity ion.

On the other hand, as shown in Comparative Examples 1 and 2, when it contained only linear polyurethane resin, it was found that the solvent resistance to n-hexane, toluene, and ethyl acetate was low.

Claims (14)

A polyester film comprising a substrate layer made of a polyester resin and an antistatic layer laminated on one surface or both surfaces of the substrate layer,
Wherein the antistatic layer comprises a water dispersible polyurethane resin consisting of 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups or a branched polymer having 3 or more terminal groups, Wherein the water-based coating composition is formed by coating and drying a water-based coating composition comprising a conductive polymer resin selected from polythiophenes or polythiophene derivatives and water. The method according to claim 1,
Wherein the antistatic layer has a surface resistance of 10 ⁵ to 10 ⁹ Ω / sq. The method according to claim 1,
Wherein the water-based coating composition further comprises one or two or more additives selected from a wetting agent, an alcohol-based solvent, particles, a slip agent, a crosslinking agent, and a hardener. The method of claim 3,
Wherein the coating composition comprises 0.1 to 10 wt% of a water dispersible polyurethane resin, 0.1 to 10 wt% of a conductive polymer resin, 0.1 to 1 wt% of a wetting agent, 0.1 to 10 wt% of an alcohol solvent, 0.1 to 10 wt% 100% by weight of water. The method according to claim 1,
Wherein the terminal group is an isocyanate group in which part or all of the terminal group is blocked with an inorganic acid base. The method according to claim 1,
The water-dispersible polyurethane resin is prepared by reacting 39 to 45% by weight of a polyol, 0.3 to 1.2% by weight of trimethylolpropane and 50 to 57% by weight of an isocyanate compound to prepare a prepolymer having isocyanate as an end group, And 4% by weight of the polyisocyanate compound were reacted to block the ionic group at the end of the isocyanate. The method according to claim 6,
The water-dispersible polyurethane resin has a weight average molecular weight of 10,000 to 20,000. The method according to claim 1,
Wherein the antistatic layer is coated by an in-line coating method. The method according to claim 1,
Wherein the antistatic layer has a dry coating thickness of 10 to 500 nm. The method according to claim 1,
Wherein the polyester film has a total thickness of 12 to 250 탆. a) melt-extruding a polyester resin to produce a polyester sheet;
b) stretching the polyester sheet in the machine direction;
c) 10 to 75% by weight of a linear polymer having 2 terminal groups and 25 to 90% by weight of a branched polymer having 3 or more terminal groups on one side or both sides of the machine direction-stretched polyester film, A water-dispersible polyurethane resin, a conductive polymer resin selected from a polythiophene or a polythiophene derivative, and water, and then stretching in the transverse direction; And
d) opening and fixing the biaxially stretched polyester film;
≪ / RTI > 12. The method of claim 11,
Wherein the water-based coating composition further comprises one or two or more additives selected from a wetting agent, an alcohol-based solvent, a particle, a slip agent, a crosslinking agent, and a curing agent. 12. The method of claim 11,
Wherein the coating composition comprises 0.1 to 10 wt% of a water dispersible polyurethane resin, 0.1 to 10 wt% of a conductive polymer resin, 0.1 to 1 wt% of a wetting agent, 0.1 to 10 wt% of an alcohol solvent, 0.1 to 10 wt% By weight of water and 100% by weight of water. 12. The method of claim 11,
Wherein the terminal group is an isocyanate group in which part or all of the terminal group is blocked with an inorganic acid base.