KR101693792B1 - Anti-static polyester film having excellent oligomer blocking property - Google Patents

Abstract

The present invention relates to an antistatic polyester film having excellent oligomer barrier properties and antistatic properties, which are difficult to be compatibilized with conventional oligomers at the same time, and more specifically to an antistatic polyester film excellent in blocking oligomers of a coating layer, To an antistatic polyester film excellent in oligomer blocking property capable of eliminating oligomer precipitation on the surface and imparting antistatic property to eliminate quality defects and process anxiety due to static electricity accumulated on the film surface. To this end, the oligomer blocking antistatic polyester film according to the present invention is formed by coating a coating composition containing an optimal ratio of a conductive polymer resin, a water-dispersible acrylic resin, a crosslinking agent and a surfactant on at least one surface of a polyester base film And a coating layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an antistatic polyester film excellent in oligomer blocking property.

The present invention relates to an antistatic polyester film having excellent oligomer barrier properties and antistatic properties, which are difficult to be compatibilized with conventional oligomers at the same time, and more specifically to an antistatic polyester film excellent in blocking oligomers of a coating layer, To an antistatic polyester film excellent in oligomer blocking property capable of eliminating oligomer precipitation on the surface and imparting antistatic property to eliminate quality defects and process anxiety due to static electricity accumulated on the film surface.

In general, polyester films are excellent in mechanical properties, heat resistance, transparency and chemical resistance while being well-elastic, so that they can be used for optical members, photographs, schemes, oh-echipi, electric and electronic parts, It is widely used across all industries.

However, in spite of the excellent physical properties of the polyester film described above, there is a problem in that due to the whitening phenomenon in which a film is present in the film or hydrolyzed oligomers are precipitated on the surface during heat treatment at a high temperature, If the polyester film is used in a product that requires high transparency even after the heat treatment step in the process, it is necessary to further hard coat the product. In addition, the polyester film has a problem that the surface of the film is easily charged if friction is applied because the resistivity of the film surface is very large. When the polyester film is charged, foreign matter such as dust tends to adhere to the film surface due to static electricity, and electrical shock is likely to be applied to the product to which the film is applied, thereby causing defective products.

As a means for suppressing the whitening phenomenon due to oligomer precipitation of the polyester film, attempts have been made to produce a film using a polyester raw material having a reduced oligomer content in the polymerization process, but it is insufficient to sufficiently block oligomer precipitation. There are also attempts to control the outflow of oligomers by forming an oligomer barrier coating layer on the polyester film, and many techniques have been reported to give oligomer blocking performance at a certain level.

In the case of a product requiring an oligomer blocking performance at the time of the high-temperature heat treatment as described above, antistatic properties are often required simultaneously, but a coating composition in which oligomer blocking performance and antistatic property are simultaneously achieved, and a polyester film produced therefrom have been reported It does not exist.

Accordingly, the present inventors have made a polyester film having an excellent appearance and high durability at the same time by having an oligomer blocking property and an antistatic property by an in-line coating method by applying an optimum content of a conductive polymer resin, a water-dispersible acrylic resin, a crosslinking agent and a surfactant Thereby completing the present invention.

Korean Patent Publication No. 10-2014-0092290

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an antioxidant composition capable of simultaneously imparting an oligomer blocking property and an antistatic property at high temperature heat treatment, And to provide such an excellent antistatic polyester film.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The object is achieved by a coating composition comprising a coating layer formed on at least one side of a polyester base film by applying an oligomeric blocking antistatic coating composition, wherein the oligomeric blocking antistatic coating composition comprises a conductive polymer resin (A) (B) a water-dispersible acrylic resin containing at least one functional group selected from the group consisting of a carboxyl group, an N-methylol group, an alkoxymethylol group, an acrylate group and an acryloyl group, an isocyanate-, melamine-, epoxy-, (C) and at least one surfactant (D) selected from the group consisting of an isocyanate-based monomer, an imide-based monomer, an imide-based monomer and a midazoline-based monomer.

The oligomer-barrier antistatic coating composition is prepared by mixing 300 to 3000 parts by weight of the water-dispersible acrylic resin (B), 30 to 2000 parts by weight of the cross-linking resin (C) with 100 parts by weight of the conductive polymer resin (A) And 0.001 to 30 parts by weight of a surfactant (D).

Preferably, the conductive polymer resin (A) may be an aqueous dispersion containing a polyanion and a polythiophene or an aqueous dispersion containing a polyanion and a polythiophene derivative.

Preferably, the oligomeric barrier antistatic coating composition may have a solids content of 0.5 to 15.0 wt% based on 100 wt% of the total coating composition.

Preferably, the water-dispersible acrylic resin (B) may be a water-dispersible acrylic resin containing a hydroxyl group, a carboxyl group and an N-methylol group.

Preferably, the non-coated surface of the polyester film is hard coated with an acrylate-based UV resin, and after heating at 150 DEG C for 60 minutes, a haze change rate (DELTA Haze) defined by the following formula (1) p or less.

(1)

After heating at? Haze = 150 占 폚 for 60 minutes, the haze of the film - the haze

More preferably, the surface resistance of the applied layer to which the oligomer barrier coating composition of the polyester film is applied may be from 10 ⁵ to 10 ¹¹ Ω / sq.

According to the present invention, an oligomer barrier property is imparted to prevent whitening of a film after heat treatment, antistatic property is imparted, and an effect of preventing process anxiety and quality defect due to static electricity at the time of friction and peeling can be obtained have.

The present invention also provides an oligomer-barrier antistatic polyester film excellent in oligomer blocking, antistatic property and abrasion resistance even in an in-line coating method by applying an oligomer-barrier antistatic coating composition to one side or both sides of a polyester film by an in- Can be provided.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

Hereinafter, the present invention will be described in detail with reference to examples of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. Also, although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

The antistatic polyester film having excellent oligomer blocking property according to one aspect of the present invention includes a coating layer formed by coating an oligomer-blocking antistatic coating composition on at least one side of a polyester base film, wherein the oligomer barrier antistatic The coating composition comprises a water-dispersible acrylic resin (A) containing at least one functional group selected from the group consisting of a conductive polymer resin (A), a hydroxyl group, a carboxyl group, an N-methylol group, an alkoxymethylol group, an acrylate group and an acryloyl group B), an isocyanate-based, melamine-based, epoxy-based, carbodiimide-based and oxazoline-based crosslinking agent resin (C) and a surfactant (D).

Hereinafter, each composition of the oligomer-barrier antistatic coating composition according to one embodiment of the present invention will be described in detail.

Conductive polymer resin (A)

The conductive polymer resin (A) contained in the oligomer-barrier antistatic coating composition according to one embodiment of the present invention is preferably an aqueous dispersion containing a polyanion and a polythiophene or a polyanion And a polythiophene derivative are 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 poly maleic acid, and examples of the polymeric sulfonic acid include polystyrene sulfonic acid and the like.

In the case of the polythiophene or polythiophene derivative, it is preferable that the solid weight ratio of the polyanion is excessively present in terms of imparting conductivity. For example, when 1 wt% of the polythiophene or polythiophene derivative is used, the amount of the polyanion is preferably greater than 1 wt%, and more preferably 5 wt% or less. More preferably in the range of 1 to 3% by weight. In one embodiment of the present invention, an aqueous dispersion containing 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000) is used, but the present invention is not limited thereto.

The water-dispersible acrylic resin (B), the crosslinking agent (C)

The water-dispersible acrylic resin (B) and the cross-linking agent (C) contained in the oligomer-barrier antistatic coating composition according to one embodiment of the present invention are applied to the polyester film at an optimum ratio to form an oligomer- Can be given. The water-dispersible acrylic resin is preferably a water-dispersible acrylic resin containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an N-methylol group, an alkoxymethylol group, an acrylate group and an acryloyl group .

Preferably, the water-dispersible acrylic resin (B) may be a water-dispersible acrylic resin containing a hydroxyl group, a carboxyl group and an N-methylol group.

The crosslinking agent may be at least one crosslinker resin selected from the group consisting of isocyanate-based, melamine-based, epoxy-based, carbodiimide-based and oxazoline-based resins.

At this time, the acrylic resin (B) and the crosslinking agent (C) may be applied to the polyester film at an optimum ratio to form an oligomer blocking property by forming a dense coating film. The crosslinking agent may be 10-50 wt% If the amount is less than 10 parts by weight or more than 50 parts by weight, the blocking performance of the oligomer is deteriorated.

Surfactant (D)

The oligomer-barrier antistatic coating composition according to an embodiment of the present invention is preferably added with a surfactant for improving the stability, wetting, and leveling of the coating composition.

In addition, by containing a small amount of inorganic nanoparticles other than the above-mentioned components, the running property of the film can be improved.

In one embodiment of the present invention, the oligomer-barrier antistatic coating composition comprises 300 to 3000 parts by weight of the water-dispersible acrylic resin (B), 30 to 2000 parts by weight of the crosslinking agent resin (C) per 100 parts by weight of the conductive polymer resin (A) And 0.001 to 30 parts by weight of a surfactant (D).

The oligomer-barrier antistatic coating composition is preferably prepared so that the solid content is 0.5 to 15.0 wt%, more preferably 7.0 to 12.0 wt%, based on 100 wt% of the entire coating composition . If the content of the solid content is less than 0.5% by weight, it is not sufficient to exhibit the coating film formation and antistatic function of the coating layer, and if it exceeds 15% by weight, it affects the transparency of the film.

In addition, the oligomeric barrier antistatic coating composition is an aqueous coating solution as the solvent used therein is substantially water-based.

The antistatic polyester film having excellent oligomer blocking properties according to an embodiment of the present invention is obtained by hard coating an uncoated surface of a polyester film with an acrylate-based UV resin, heating it at 150 占 폚 for 60 minutes, The defined haze change rate (ΔHaze) may be less than 0.1% p.

(1)

After heating at? Haze = 150 占 폚 for 60 minutes, the haze of the film - the haze

Also, the surface resistance of the coated layer to which the oligomer barrier coating composition of the polyester film is applied may be 10 ⁵ to 10 ¹¹ Ω / sq.

Next, a method for producing an antistatic polyester film excellent in oligomer blocking property according to another aspect of the present invention is as follows.

A first step of preparing the aforementioned oligomer-barrier antistatic coating composition comprising a conductive polymer resin and a water-dispersible acrylic resin, a crosslinking agent and a surfactant;

A second step of uniaxially stretching the polyester film,

A third step of coating the polyester film obtained by the first step on one side or both sides of the uniaxially stretched polyester film with an oligomer blocking antistatic coating composition by an inline coating method to form a coating layer,

And a fourth step of re-stretching the polyester film on which the coating layer is formed in the direction perpendicular to the uniaxial stretching direction to produce a biaxially stretched polyester film.

Therefore, according to another aspect of the present invention, an oligomer blocking antistatic polyester film excellent in oligomer blocking, antistatic property and abrasion resistance can be produced even in an in-line coating method.

The antistatic polyester film having excellent oligomer blocking properties prepared as described above contains an acrylic resin, a conductive polymer resin, a crosslinking agent, and a surfactant at an optimum ratio by the inline coating method and has excellent oligomer blocking property and antistatic property It is excellent in coating appearance and excellent in durability, so that it is possible to prevent the oligomer from precipitating on the surface after heating the polyester film and to have an antistatic property.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

The binder resins used in Examples and Comparative Examples are as follows.

1) A-30 binder

An ethylenically unsaturated monomer having a carboxyl group in the molecule, an ethylenically unsaturated monomer having a hydroxyl group in the molecule, an unsaturated carboxylic acid having an N-methylol group in the molecule, and an unsaturated carboxylic acid having an N-methylol group in the molecule, as an aqueous dispersion of an aqueous acrylic copolymer having a weight average molecular weight of 2,000,000. An aqueous dispersion of an acrylic copolymer comprising an ethylenically unsaturated monomer having a hydroxy group in an amount of 40% by weight based on the total monomer components, the aqueous emulsion being prepared through copolymerization of a carboxylic acid amide monomer.

2) A-07 binder

A water-dispersible acrylic copolymer aqueous dispersion having a weight average molecular weight of 2,000,000, an aqueous dispersion prepared by copolymerizing a methacrylic acid ester monomer, an ethylenically unsaturated monomer having a carboxyl group in a molecule, and an unsaturated carboxylic acid amide monomer having an N- emulsion.

≪ Example 1 >

100 parts by weight of a conductive polymer resin (aqueous dispersion containing 0.5% by weight of poly 3,4-ethylenedioxythiophene and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000)), 1000 parts by weight of A-30 binder, Chemicals, MW12LF) and 1 part by weight of a surface active agent (DYNOL-607, manufactured by Air Products Co.) were mixed with water to prepare a coating composition, which was then applied to a polyester film having a thickness of 125 μm. At this time, the solid content of the coating composition is supposed to contain 10 wt% of the total coating composition, and the thickness of the coating layer is 150 nm.

≪ Example 2 >

100 parts by weight of a conductive polymer resin (aqueous dispersion containing 0.5% by weight of poly 3,4-ethylenedioxythiophene and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000)), 2000 parts by weight of A-30 binder, Chemicals, MW12LF) and 2 parts by weight of a surface active agent (DYNOL-607, manufactured by Air Products Co.) were mixed with water to prepare a coating composition, and the coating composition was applied to a polyester film having a thickness of 125 μm. At this time, the solid content was 10 wt% of the total coating solution, and the thickness of the coating layer was 150 nm.

≪ Comparative Example 1 &

A polyester film was produced in the same manner as in Example 1, except that the conductive polymer resin was not added.

≪ Comparative Example 2 &

The procedure of Example 1 was repeated except that the A-07 binder was used to prepare a polyester film.

The polyester films of Examples 1 and 2 and Comparative Examples 1 and 2 were used to measure physical properties through the following experimental examples, and the results are shown in Table 1 below.

[Experimental Example]

1. Antistatic measurement

The sample was placed under an environment of a temperature of 23 DEG C and a humidity of 50% RH using an antistatic measuring device (Mitsubishi KK; model name: MCP-T600), and the surface resistance of the film was measured according to JIS K7194.

2. Measurement of oligomer blocking property

The haze was measured using a haze meter manufactured by Nippon Denshoku, and the haze change before and after the heating was measured by the following equation (1). At this time, the uncoated surface of the polyester film was hard coated with an acrylate-based UV resin to measure the haze, and the haze after heating at 150 DEG C for 60 minutes was measured.

(1)

ΔHaze = (haze of film after heating at 150 ° C. for 60 minutes - haze of film before heating)

division Surface resistance (Ω / sq) ΔHaze Example 1 1 x ^{10 8} 0.07% p Example 2 6x10 ⁸ 0.03% p Comparative Example 1 1x10 ¹² or more 0.01% p Comparative Example 2 4x10 ⁸ 1.5% p

As can be seen from the above Table 1, it can be seen that the lower the content of the conductive polymer, the lower the antistatic property and the higher the oligomer barrier property. That is, increase in haze due to surface run-off of the oligomer is suppressed. It can also be seen that there is a large difference in the oligomer blocking property depending on the type of acrylic resin. That is, in the acrylic resin of Example 1, the barrier properties of the oligomer were poor in the case of Comparative Example 2 using an acrylic resin not containing hydroxy.

Therefore, according to the present invention, oligomer blocking and antistatic properties can be achieved by optimizing the ratio of the acrylic resin and the antistatic agent.

The antistatic polyester film having excellent oligomer blocking property according to the present invention can provide a film simultaneously providing oligomer blocking and antistatic property at high temperature heat treatment which has been difficult to achieve in the prior art. In particular, The value of industrial use as a member for TSP is very high.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (7)

A coating layer formed on at least one side of the polyester base film by applying an oligomeric blocking antistatic coating composition,
The oligomer-barrier antistatic coating composition is a water-dispersible acrylic resin (B) containing a conductive polymer resin (A), a methacrylic ester, a hydroxyl group, a carboxyl group and an N-methylol group, an isocyanate-based, melamine- (C) and a surfactant (D) selected from the group consisting of a carbodiimide-based compound and an oxazoline-based compound, and an antioxidant (D). The method according to claim 1,
The oligomer blocking antistatic coating composition is prepared by mixing 300 to 3000 parts by weight of the water-dispersible acrylic resin (B), 30 to 2000 parts by weight of the crosslinking resin (C), and 100 to 2000 parts by weight of the surfactant (B) with respect to 100 parts by weight of the conductive polymer resin (D) in an amount of from 0.001 to 30 parts by weight. The method according to claim 1,
The conductive polymer resin (A) is an aqueous dispersion containing a polyanion and a polythiophene-containing aqueous dispersion or a polyanion and a polythiophene derivative. The method according to claim 1,
Wherein the oligomer blocking antistatic coating composition has a solid content of 0.5 to 15.0% by weight based on 100% by weight of the total coating composition. delete The method according to claim 1,
The non-coated surface of the polyester film is hard coated with an acrylate-based UV resin, and after heating at 150 캜 for 60 minutes, the haze change rate (ΔHaze) defined by the following formula (1) By mass, and having excellent oligomer blocking property.
(1)
After heating at? Haze = 150 占 폚 for 60 minutes, the haze of the film - the haze The method according to claim 1,
Wherein the coating layer on which the oligomer barrier coating composition of the polyester film is applied has a surface resistance of 10 ⁵ to 10 ¹¹ Ω / sq.