KR102083074B1 - Antistatic coating solution composition and antistatic polyester film using the same - Google Patents

Abstract

The present invention provides an antistatic polyester film having an antistatic coating liquid composition comprising a modified conductive composite, a crosslinking agent, a binder, and a dispersibility improving agent having excellent antistatic properties and a coating layer coated on at least one side of the polyester film. It has a good appearance quality, very good transparency and smoothness, and has a stable antistatic performance even under low humidity and has a coating layer that is difficult to deteriorate over time, which can effectively prevent the adsorption of dust and the generation of static electricity. It relates to an antistatic coating liquid composition and an antistatic polyester film using the same.

Description

Antistatic coating liquid composition and antistatic polyester film using same {ANTISTATIC COATING SOLUTION COMPOSITION AND ANTISTATIC POLYESTER FILM USING THE SAME}

The present invention relates to an antistatic coating liquid composition and an antistatic polyester film using the same, and more particularly, to an antistatic coating liquid composition and an antistatic polyester using the same, which can effectively prevent the adsorption of dust and generation of static electricity. It is about a film.

In general, the polymeric polymer film has excellent mechanical strength, dimensional stability, heat resistance, transparency, and chemical resistance, so it is widely used in all fields of industry for photography, drafting, O.P., electrical and electronic parts, general industry, and packaging materials. It is widely used throughout.

However, in spite of the excellent physical properties of the polymerized polymer film, the resistivity of the film surface is so large that the surface of the film is easily charged when friction is applied. In this case, foreign matter such as dust adheres to the film surface by static electricity or Electric shock is applied and product defect occurs.

Moreover, the film by which chemical substances, such as an organic solvent, are used may discharge in a manufacturing process or a processing process, and a fire may arise.

As a known technique of suppressing the generation of static electricity of such a film, an internal addition method of mixing organic sulfonate or organic phosphate in the production of a film, a metal deposition method of depositing a metal compound on the surface, and a method of applying conductive inorganic particles to the surface , An ionic monomolecular compound or a high molecular compound is applied to the surface.

Among these methods, the internal addition method is excellent in stability against changes over time, but has a problem in that the excellent physical properties and antistatic effects of the film are reduced, and the metal deposition method and the method of applying conductive inorganic particles are excellent in antistatic properties. Although it has been spotlighted recently, it is used only in a special field requiring a high antistatic property because the manufacturing cost is too high. In addition, as a technique for applying an ionic monomolecular compound or a polymer compound, Korean Laid-Open Patent Publication No. 2003-0022713 discloses an antistatic polyester film using polydiaryldimethylammonium chloride, which is a polymer quaternary ammonium, as an antistatic agent. Related arts are disclosed, US Patent No. 5,925,447 describes a technique using an acrylic polymer having a quaternary ammonium group attached to an acryl amide end as an antistatic agent, and Korean Patent Application Publication No. 2002-0010877 discloses a quaternary ammonium chloride. Disclosed is an antireflection film in which a silicon compound containing a cation-modified silicon compound is coated on a base film and cured to form a low reflection layer.

However, all antistatic films produced in these manners have a problem in that the antistatic properties change with humidity, so that the antistatic properties cannot be properly implemented at low humidity.

In addition, Korean Laid-Open Patent Publication No. 2006-0078766 discloses forming a coating layer on a polyester film by coating and drying a coating liquid containing a conductive polymer, a fluorine-based silane coupling agent, and a curing agent on one side of the polyester film. have.

However, since the coating layer disclosed in Korean Laid-Open Patent Publication No. 2006-0078766 may cause poor appearance such as deterioration of transparency or whitening, a polyester film having such a coating layer can be applied to optical applications. In addition, there is a disadvantage that it is difficult to apply to high-speed production due to the aggregation of the coating liquid is caused due to the stability of the coating liquid over time.

Korean Laid-Open Patent Publication No. 2003-0022713 U.S. Patent 5,925,447 Korean Unexamined Patent Publication No. 2002-0010877 Korean Laid-Open Patent Publication No. 2006-0078766

The present invention has been made to solve the above problems, the object of the present invention is good appearance quality, very good transparency and smoothness, and also has a stable antistatic performance under low humidity and difficult to deteriorate over time It is to provide an antistatic coating liquid composition and an antistatic polyester film using the same that can effectively remove the surrounding dust adsorption and static electricity by providing a.

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

The object is, as an antistatic coating liquid composition, including a conductive composite containing a π-conjugated conductive polymer and a compound having a structure of formula (1), a crosslinking agent, a binder resin and a dispersibility enhancer,

[Formula 1]

Wherein R _{1 and} R ₂ are each independently a linear or branched alkylene group having 2 to 12 carbon atoms, an alkyl group, an alkenyl group, a vinyl group, an allyl group, a phenyl group, an aryl group, and B ⁺ is a cation. It is achieved by the antistatic coating liquid composition.

Here, the compound having the structure of Formula 1 is characterized in that 3-sulfopropyl acrylate potassium salt (3-sulfopropyl acrylate potassium salt).

Preferably, the conductive composite is characterized in that it comprises 0.1 to 6 parts by weight of solids of the compound having the structure of Formula 1 per 1 part by weight of the π-conjugated conductive polymer.

Preferably, the conductive composite is a water dispersion containing a polythiophene or a derivative thereof as a π-conjugated conductive polymer and a compound having the structure of Formula (1).

Preferably, the crosslinking agent is characterized in that at least one selected from the group consisting of carbodiimide compound, isocyanate compound, oxazoline compound, melamine compound and epoxy compound.

Preferably, the molecular weight of the crosslinking agent is characterized in that 1,000 or less.

Preferably, the crosslinking agent is characterized in that it contains 10 to 85% by weight relative to the total weight of the coating liquid composition.

Preferably, the binder resin is characterized in that the thermoplastic resin having a hydrophilic group.

Preferably, the binder resin is characterized in that it comprises 10 to 1000 parts by weight based on 100 parts by weight of the conductive composite.

Preferably, the dispersibility enhancer is a nitrogen-containing compound or a hydroxyl-containing compound.

Preferably, the coating liquid composition is characterized in that it further comprises 0.002 to 10 parts by weight of the surfactant as a solid with respect to 100 weight of the coating liquid composition.

Preferably, the surfactant is characterized in that the acetylene diol-based surfactant.

Preferably, the coating liquid composition satisfies Equation 5 below,

[Equation 1]

5 ≤ Z ≤ 12

Here, Z is characterized in that the hydrogen ion concentration of the coating liquid composition.

In addition, the object includes a coating layer coated with the polyester film and the antistatic coating liquid composition described above on at least one side of the polyester film,

Satisfy all of the following Equations 2 to 5,

[Equation 2]

X ₁ <10 ¹¹ ,

[Equation 3]

X ₂ <10 ¹¹ ,

[Equation 4]

ㅣ Log X ₁ -LogX ₂ ㅣ <1

[Equation 5]

5 ≤ Y ≤ 50

Where X ₁ and X ₂ (Ω / sq) are the surface resistances of the coating layer at a temperature of 23 ° C. and 65% RH and a temperature of 23 ° C. and 30% RH, respectively, and Y is a three-dimensional surface of at least one side of the film. It is achieved by an antistatic polyester film, characterized in that it is a centerline average roughness.

According to the present invention, the appearance quality is good, the transparency and smoothness is very good, and it has a stable antistatic performance even under low humidity and has a coating layer that is difficult to deteriorate with time, thereby effectively preventing the adsorption of dust and generating static electricity. There is such an effect.

Furthermore, the present invention has the effect of improving the workability and productivity in the film manufacturing process.

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

1 is a schematic cross-sectional view of an antistatic polyester film according to a preferred embodiment of the present invention.
2 is a schematic cross-sectional view of an antistatic polyester film according to another preferred embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples. .

Unless defined otherwise, 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.

In describing and / or claiming the present invention, the term "copolymer" is used to refer to a polymer formed by copolymerization of two or more monomers. Such copolymers include dipolymers, terpolymers or higher copolymers.

The inventors of the antistatic coating liquid composition according to the present invention and the antistatic polyester film using the same have studied the problems of the prior art described above, and as a result, a modified conductive composite, a crosslinking agent, a binder, and a dispersibility enhancer having excellent antistatic properties When the coating layer is used in combination with each other, it is found that the appearance quality is good, the antistatic performance is difficult to deteriorate with time, and all the other characteristics have excellent results.

1 and 2 are schematic cross-sectional views of an antistatic polyester film according to a preferred embodiment of the present invention, respectively, wherein a coating layer is formed on at least one surface of the film and the film. That is, the antistatic polyester film according to the present invention means that the coating layers may be formed on one side of the film as shown in FIG. 1 or both sides of the film as shown in FIG. 2.

An antistatic polyester film according to an aspect of the present invention includes a coating layer coated on at least one side of a polyester film and a polyester film with an antistatic coating liquid composition described below.

The type of polyester film according to an embodiment may be used without particular limitation as long as it is a conventional resin known as a base film to which an antistatic coating layer is applied. In the present invention, polyethylene terephthalate, polybutylene terephthalate, polyethylene or Although described mainly with respect to polyester-based resins such as phthalates, it will be understood that the present invention is not limited thereto.

This polyester film refers to the polyester obtained by polycondensing aromatic dicarboxylic acid and aliphatic glycol, and aromatic dicarboxylic acid uses terephthalic acid, 2,6-naphthalenedicarboxylic acid, and the like, except for dika of copolyester. As phthalic acid component, isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, P-oxybenzoic acid, etc.) can be used. Examples of the aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol, propylene glycol, butanediol, neopentyl glycol, and the like, and these dicarboxylic acid components and glycol components are each two kinds. You may use together the above. Representative polyester films include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like, and copolymers containing a third component in polyester are also possible.

Antistatic coating liquid composition according to another aspect of the present invention is a conductive composite (A), a crosslinking agent (B), a binder resin (C) and a dispersibility enhancer comprising a π-conjugated conductive polymer and a compound having the structure of Formula 1 (D) may be included.

[Formula 1]

In Formula 1, R _{1 and} R ₂ are each independently a linear or branched alkyl group having 2 to 12 carbon atoms, an alkyl group, an alkenyl group, a vinyl group, an allyl group, a phenyl group, an aryl group, and B ⁺ is a cation. It is a cation that can dissociate and charge.

The conjugate conjugated conductive polymer according to the present invention can be used as long as the main chain is an organic polymer composed of a conjugated conjugated system. For example, polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes and copolymers thereof are mentioned. From the viewpoint of ease of polymerization and stability in air, polypyrroles, polythiophenes and polyanilines are preferred.

Specific examples of such π-conjugated conductive polymers include polypyrrole, poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-n-propylpyrrole), poly (3-butylpyrrole) and poly (3-). Octylpyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole), poly (3-carboxypyrrole) , Poly (3-methyl- 4-carboxypyrrole), poly (3-methyl- 4-carboxyethylpyrrole), poly (3-methyl- 4-carboxybutylpyrrole), poly (3-hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-hexyloxypyrrole), poly (3-methyl-4-hexyloxypyrrole), Poly (N-methylpyrrole), poly (thiophene), poly (3-methylthiophene), poly (3-ethylthiophene), poly (3-propylthiophene), poly (3-butylthiophene), Poly (3-hexylthiophene), poly (3-heptylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-octa) Decylthiophene), Paul (3-bromothiophene), poly (3-chlorothiophene), poly (3-iodinethiophene), poly (3-cyanothiophene), poly (3-phenylthiophene), poly (3,4- Dimethylthiophene), poly (3,4-dibutylthiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene), poly (3-butoxide Citofene), poly (3-hexyloxythiophene), poly (3-heptyloxythiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxy Citofene), poly (3-octadecyloxythiophene), poly (3,4-dihydroxythiophene), poly (3,4-dimethoxythiophene), poly (3,4-diethoxythiophene) ), Poly (3,4-dipropoxythiophene), poly (3,4-dibutoxythiophene), poly (3,4-dihexyloxythiophene), poly (3,4-diheptyloxythiophene) , Poly (3,4-dioctyloxythiophene), poly (3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), Poly (3,4-propylenedioxythiophene), Paul Li (3,4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly (3-carboxythiophene), poly (3 -Methyl- 4-carboxythiophene), poly (3-methyl- 4-carboxyethylthiophene), poly (3-methyl- 4-carboxybutylthiophene), polyaniline, poly (2-methylaniline), poly ( 3-isobutylaniline), poly (2-aniline sulfonic acid), poly (3-aniline sulfonic acid), and the like.

The conductive composite (A) according to one embodiment is used to give excellent antistatic performance, and preferably, an aqueous dispersion containing a compound having a structure of Formula 1 and polythiophene and / or a derivative thereof may be used. .

In one embodiment, as a preferred compound of the compound having the structure of Formula 1 (hereinafter, also referred to as “dopant”), 3-sulfopropyl acrylate potassium salt may be used, but is not limited thereto. .

The solid weight ratio of such a dopant is preferably 0.1 to 6 parts by weight, more preferably 1 to 5 parts by weight per 1 part by weight of polythiophene or polythiophene derivative. This is because the dopant is included in the above range, thereby ensuring sufficient solubility and forming sufficient doping to express excellent antistatic property.

Thus, the following examples are described using an aqueous dispersion containing 0.5 part by weight of poly (3,4-ethylenedioxythiophene) and 1.0 part by weight of 3-sulfopropyl acrylate potassium salt, but is not limited thereto.

The crosslinking agent (B) according to the present invention is used to improve the solvent resistance and coating film performance of the antistatic coating layer and the polyester film by controlling the crosslinking density. At this time, the preferred crosslinking agent may be at least one selected from the group consisting of carbodimide compounds, isocyanate compounds, oxazoline compounds, melamine compounds and epoxy compounds.

In one embodiment, the crosslinking agent is not particularly limited but it is suitable that the molecular weight of the crosslinking agent is 1000 or less. In particular, when the crosslinking agent is water-soluble and the molecular weight is 1000 or less, the flexibility and fluidity in the stretching step are expressed, the stretchability after drying of the mixture forming the coating layer is suppressed, the whitening phenomenon caused by cracking of the coating film is suppressed, and transparency is imparted. However, when the molecular weight of a crosslinking agent becomes larger than the said range, since the phenomenon which a crack enters in a coating film at the time of extending | stretching after application | coating and drying arises, transparency tends to fall. Moreover, by making molecular weight 800 or less, More preferably, 600 or less, it becomes easy to be compatible with another coating composition, and transparency can be improved.

The amount of the crosslinking agent in the total weight of the antistatic coating liquid composition is not limited, but is preferably 85% by weight or less, more preferably 65% by weight or less, even more preferably 50% by weight or less. By setting the upper limit of the amount of the crosslinking agent in this way, the appearance quality and transparency of the antistatic coating layer are further improved. In addition, the amount of the crosslinking agent in the total weight of the antistatic coating liquid composition is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more. This is because by setting the lower limit of the amount of the crosslinking agent in this way, the whitening phenomenon caused by the weakening of the solvent resistance is reduced, and it becomes difficult to deteriorate with time in the antistatic performance.

The binder resin (C) according to the present invention is a water-soluble or water dispersion type, and it is preferable to use a thermoplastic resin having at least one hydrophilic group, if necessary. Examples of such binder resins include polyether resins, polyester resins, polyurethane resins, acrylic resins, vinyl resins, epoxy resins, and amide resins. The skeleton of the binder resin may have a substantially complex structure, for example, by copolymerization. By containing binder resin in a coating liquid composition, the antistatic coating layer obtained improves strength and adhesiveness to a base film.

More specifically, preferred binder resins are polyether polyurethane water dispersions of anions containing hydroxyl groups; Functional group of a repeating unit selected from the group consisting of allylamine, vinylamine, ethyleneamine, vinyl pyridine, diethylaminoethyl methacrylate, diallyldimethylammonium chloride, methacryloyloxyethyltrimethylammonium sulfate and combinations thereof Polyether polyurethane water dispersion of anion containing; Or an anionic polyether polyurethane aqueous dispersion comprising a functional group of a repeating unit selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl and combinations thereof.

Moreover, it is preferable that the quantity of binder resin adds 10-1000 weight part of binder resin with respect to 100 weight part of conductive composites. At this time, if the amount of the binder resin added is less than 10 parts by weight, the adhesive force of the coating layer is lowered, causing problems in use, and if it exceeds 1000 parts by weight, coating defects occur, affecting product quality.

The dispersibility improving agent (D) according to the present invention may use a nitrogen-containing compound or a hydroxyl group-containing compound, and is used to improve the miscibility of the binder resin and the conductive composite and to suppress aggregation of the coating composition. Specific examples include trialkylamines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, tripentylamine and trihexylamine; Trialcoholamines such as trimethanolamine, triethanolamine, triisopropanolamine, tributanolamine, and tripentanolamine, dimethylethanolamine, 2-amino-2-methyl-1-propanol and dimethylaminohydroxypropane, ammonium hydroxide Side, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, sodium hydroxide and the like can be used. These may each be used alone or in combination. The amount of the dispersibility enhancer is not limited, but preferably the hydrogen ion concentration of the final coating liquid composition may be 5-12, more preferably 6-11, and more preferably 7-10.

This dispersibility enhancer is a basic material used to improve the miscibility of the binder resin and the conductive composite and to suppress agglomeration of the coating composition, and the amount of addition depends on the type / amount of the other coating liquid composition. As the addition amount of the enhancer increases, the hydrogen ion concentration of the coating liquid composition increases.

Moreover, surfactant can be added to the coating liquid composition used for forming the antistatic coating layer of the antistatic polyester film which concerns on this invention in order to improve the applicability | paintability to a polyester film. It is preferable that surfactant used has a structure of an acetylene diol type surfactant. Such surfactant does not impair the antistatic performance of the antistatic coating layer.

In one embodiment, the acetylene diol-based surfactant may be a compound represented by the following formula (2).

[Formula 2]

In formula (2), R ₁ , R ₄ is selected from a C2-C10 linear or branched alkyl group, cyano group, amino group, hydroxyl group, carbonyl group, ester group or carboxyl group, R ₂ , R ₃ is hydrogen or C1-C8 alkyl group , m, n, p and q are preferably integers of 0 to 20. For example, 2,5,8,11-tetramethyl-6-dodecine-5,8-diol ethoxylate.

In addition, preferable content of an acetylene diol type surfactant can be added in 0.002-10 weight part as solid content with respect to 100 weight part of all antistatic coating liquid compositions. If the amount of the surfactant added is less than 0.002 parts by weight, the wettability of the coating film is lowered, and if it exceeds 10 parts by weight, it is because coating appearance defects are caused due to fine bubbles in the coating composition.

In addition, the antistatic coating liquid composition according to the present invention is preferably prepared so that the content of solids is 0.5 to 10.0 parts by weight, and more preferably 1.0 to 5.0 parts by weight, based on 100 parts by weight of the total coating liquid composition. It can be manufactured as possible. If the content of the solid content is less than 0.5 parts by weight, it is not sufficient to express the film formation and the antistatic function of the coating layer, and if it exceeds 10.0 parts by weight, the transparency of the film is affected, which is not preferable.

In one embodiment, the solvent used in the antistatic coating liquid composition according to the present invention is preferably water based as the main medium can be substantially water.

Furthermore, for the purpose of improving the applicability to the coating liquid used in the present invention, improving the transparency, and the like, a suitable organic solvent of a degree that does not impair the effects of the present invention may be contained, and isopropyl alcohol is preferable. , Butyl cellosolve, t-butyl cellosolve, ethyl cellosolve, acetone, ethanol, methanol and the like can be used. However, when a large amount of organic solvent is contained in the coating composition, when applied to the in-line coating method, there is a risk of explosion in the drying, stretching and heat treatment processes, so that the content is 10% by weight or less, more preferably 5% by weight in the coating composition. Control is as follows.

In one embodiment of the present invention, the coating liquid composition preferably satisfies Equation 1 below.

[Equation 1]

5 ≤ Z ≤ 12

In Equation 1, Z is the hydrogen ion concentration of the coating liquid composition.

In addition, the antistatic polyester film according to an embodiment of the present invention preferably satisfies all the following Equations 2 to 5.

[Equation 2]

X ₁ <10 ¹¹ ,

[Equation 3]

X ₂ <10 ¹¹ ,

[Equation 4]

ㅣ Log X ₁ -LogX ₂ ㅣ <1

[Equation 5]

5 ≤ Y ≤ 50

Here, X ₁ and X ₂ (Ω / sq) in Equations 2 to 4 are surface resistances of the coating layer at a temperature of 23 ° C. and a relative humidity of 65% RH and a temperature of 23 ° C. and a relative humidity of 30% RH, respectively. Y is the three-dimensional centerline average roughness (nm) of at least one side of the film.

The antistatic coating layer provided on one side of the polyester film has a low surface resistivity and has a property of leaking electric charges. In order to bring good antistatic performance, the surface resistivity of the antistatic coating layer is preferably as low as possible, specifically, it is preferably less than 1 × ^{10 11} Ω / □, more preferably 1 × ^{10 9} Ω / □ or less.

In addition, it is necessary for the surface roughness of the antistatic polyester film according to the present invention to have a three-dimensional center line average roughness SRa of at least one surface of 5 to 50 nm. Thereby, when used for the polarizing plate protection use etc. which are one use of the film obtained by this invention, for example, since surface smoothness is important, it is especially preferable. In addition, the three-dimensional 10-point average roughness SRz characterizes a large protrusion or depression. If these values are large, for example, projections may be recognized as foreign matters at the time of product defect inspection, and in the present invention, SRa is more preferably 10 to 35 nm, most preferably 10 to 30 nm and SRz is 1000 nm or less. It is preferable that it is 800 nm or less more preferably.

In addition, the haze of the antistatic polyester film according to the present invention is preferably 5% or less, more preferably 4% or less, and most preferably 0.9 to 3.5%. If larger than 5%, scattering of transmitted light is large and transparency is inferior, and therefore there exists a tendency for inspectability, such as a fault, to be inferior. On the other hand, when it is extremely excellent in transparency, it shows the disadvantage of the level which does not become a problem in the said use, such as a foreign material in a film, and tends to have an adverse effect.

Next, a method of manufacturing an antistatic polyester film according to another embodiment of the present invention will be described. The manufacturing method of an antistatic polyester film is as follows.

1) uniaxially stretching the polyester film;

2) forming an antistatic layer by applying an antistatic coating composition including a conductive composite to at least one side of the uniaxially stretched polyester film by an inline coating method; And

3) re-stretching the polyester film on which the antistatic coating layer is formed in a direction perpendicular to the uniaxial stretching direction to produce a biaxially stretched polyester film.

First, the one step of uniaxially stretching a polyester film is demonstrated.

The above-mentioned polyester resin is melted by an extruder after vacuum drying, extruded onto a sheet through T-DIE, adhered to a casting drum by pinning on a cooling roll, and cooled and solidified to unstretched polyester. A sheet was obtained and uniaxially stretched 2 to 6 times by the circumferential speed ratio difference between a roll and a roll in the roll heated above the glass transition temperature of a polyester resin, and a uniaxially stretched polyester film is manufactured.

In the manufacturing method according to the present invention, step 2 is a step of forming the antistatic coating layer by applying the aforementioned antistatic coating liquid composition to at least one side of the uniaxially stretched polyester film in step 1. More specifically, the method for applying the antistatic coating liquid composition may be performed by a method such as a meyer bar method or a gravure method, and by introducing a polar group on the surface of the film before application, the coating layer and the film and Corona discharge treatment may be performed to improve the adhesion and coating properties of the. At this time, since the antistatic coating liquid composition of the present invention is the same as described in the antistatic coating liquid composition according to the above-described embodiment will not be described in detail.

Step 3 of the manufacturing method according to the present invention is a step of producing a biaxially stretched polyester film by re-stretching the polyester film on which the antistatic coating layer is formed in step 2.

At this time, the stretching in three stages is performed in the direction perpendicular to the direction of the uniaxial stretching, and the preferred stretching ratio is 3.0 to 7.0 times. After the stretching process, it is possible to produce an antistatic polyester film through heat setting. The thickness of the biaxially stretched antistatic polyester film produced from the production method of the present invention is 5 to 300 mu m, preferably 10 to 250 mu m.

The antistatic coating liquid composition and antistatic polyester film using the same according to the present invention described above are coated on one side of the polyester film with a coating liquid containing a modified conductive composite, a crosslinking agent, a binder, and a dispersibility enhancer having excellent antistatic properties. It has an antistatic coating layer obtained by coating and drying it, and this antistatic coating layer has a good appearance quality, excellent transparency and smoothness, and has a stable antistatic performance even under low humidity and difficult to deteriorate with time As a result, it is possible to have an advantage that it can be used in a wide range of applications including display applications requiring antistatic performance such as optical films.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to Examples and Comparative Examples. However, this embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

<Example 1>

Step 1: Preparation of Monoaxially Stretched Polyester Film

Polyethylene terephthalate pellets having an extreme viscosity of 0.625 dl / g containing 0.02% by weight of amorphous spherical silica particles having an average particle diameter of 1.5 µm were sufficiently dried at 160 ° C. for 7 hours using a vacuum dryer, and then melted and extruded. A non-stretched sheet was formed by bringing it into close contact with a cooling drum through a tee-die by an electrostatic application method, which was then heated again and stretched 3.5 times in a film traveling direction at 95 ° C. to prepare a uniaxially stretched polyester film. Then, a corona discharge treatment was performed on the surface of the film to be applied to prepare a polyester film.

Step 2: Preparation of Biaxially Stretched Polyester Film

On the corona-treated side, a conductive composite (coating solution A; an aqueous dispersion containing 0.5 part by weight of poly3,4-ethylenedioxythiophene and 1.0 part by weight of 3-sulfopropyl acrylate potassium salt), an epoxy crosslinking agent (coating solution B; Nagase Chemtech, DENACOL EX-614), polyurethane resin (coating solution C; polyether polyurethane water dispersion of anion containing a hydroxyl group), dispersibility enhancer (ammonium hydroxide) and acetylene diol-based surfactant (coating Solution E; 2,5,8,11-tetramethyl-6-dodecine-5,8-diol ethoxylate) was mixed with water to apply an antistatic coating liquid having a solid content of 4% by weight relative to the total coating liquid. It was. The coating liquid A, the coating liquid B, the coating liquid C and the coating liquid E were mixed with the coating liquid A / coating liquid B / coating liquid C / coating liquid E = 15/60/20/5 at a solid content weight ratio. The dispersibility enhancer was added so that the hydrogen ion concentration of the antistatic coating liquid was 7.5.

The antistatic coating liquid was applied to the uniaxial polyester film prepared in Step 1 using a gravure roll, and then the coating liquid was dried in a tenter section of 105 to 140 ° C. and stretched 3.8 times in the direction perpendicular to the traveling direction of the film. Then, heat treatment was performed at 240 ° C. for 4 seconds to prepare a biaxially stretched antistatic polyester film having a thickness of 38 μm.

<Example 2>

The coating liquid A, the coating liquid B, the coating liquid C, and the coating liquid E were mixed with the coating liquid A / coating liquid B / coating liquid C / coating liquid E = 20/55/20/5 in a solid content weight ratio. In the same manner as in Example 1, a biaxially stretched antistatic polyester film was prepared.

<Example 3>

The coating liquid A, the coating liquid B, the coating liquid C and the coating liquid E were mixed with the coating liquid A / coating liquid B / coating liquid C / coating liquid E = 15/70/10/5 at a solid weight ratio. In the same manner as in Example 1, a biaxially stretched antistatic polyester film was prepared.

<Example 4>

A uniaxially oriented polyester film was prepared using polyethylene terephthalate pellets having an intrinsic viscosity of 0.625 dl / g containing 0.05 wt% of amorphous spherical silica particles having an average particle diameter of 1.5 µm, and the coating solution A was applied. Same as Example 1 except that the liquid B, the coating liquid C, and the coating liquid E were mixed at a solid weight ratio in the coating liquid A / coating liquid B / coating liquid C / coating liquid E = 50/25/20/5. To prepare a biaxially stretched antistatic polyester film.

Example 5

The coating liquid A, the coating liquid B, the coating liquid C and the coating liquid E were mixed with the coating liquid A / coating liquid B / coating liquid C / coating liquid E = 20/45/30/5 by solid content weight ratio. In the same manner as in Example 4, a biaxially stretched antistatic polyester film was prepared.

<Example 6>

Except for setting the hydrogen ion concentration of the coating liquid to 9.5, the same procedure as in Example 4 was carried out to prepare a biaxially stretched antistatic polyester film.

Comparative Example 1

Antistatic polyester biaxially stretched in the same manner as in Example 1, except that polystyrenesulfonic acid ammonium salt (coating solution F; weight average molecular weight: 10,000, aqueous coating solution dissolved in water) was used instead of coating solution A. A film was prepared.

Comparative Example 2

Example 1 Except that the film was produced from uniaxially stretched polyester using a polyethylene terephthalate pellet having an intrinsic viscosity of 0.625 dl / g containing 0.5 wt% of amorphous spherical silica particles having an average particle diameter of 4 µm. In the same manner as in the biaxially stretched antistatic polyester film was prepared.

Comparative Example 3

Example 1 Except that the film was produced from uniaxially stretched polyester using a polyethylene terephthalate pellet having an ultimate viscosity of 0.625 dl / g containing 0.2 wt% of amorphous spherical silica particles having an average particle diameter of 1.5 µm. In the same manner as in the biaxially stretched antistatic polyester film was prepared.

<Comparative Example 4>

Except for changing the hydrogen ion concentration of the coating liquid to 4,0 was carried out in the same manner as in Example 4 to prepare a biaxially stretched antistatic polyester film. However, since many aggregates generate | occur | produced in the coating liquid, the thing filtered by the filter was used for application | coating to a film.

<Comparative Example 5>

The same procedure as in Example 4 was carried out except that the coating liquid A, the coating liquid C, and the coating liquid E were mixed in a coating weight A / coating liquid C / coating liquid E = 85/10/5 in a solid content ratio. A stretched antistatic polyester film was prepared.

Comparative Example 6

Example 2 was carried out in the same manner as in Example 1, except that the coating liquid A, the coating liquid B and the coating liquid E were mixed at a solid weight ratio to the coating liquid A / coating liquid B / coating liquid E = 90/5/5. An axially stretched antistatic polyester film was prepared.

Using the antistatic polyester film according to Examples 1 to 6 and Comparative Examples 1 to 6 to measure the physical properties through the following experimental example and the results are shown in Table 1 below.

Experimental Example

1. Optical Properties

A sample of 10 cm x 10 cm sampled coated film was placed vertically on a haze measuring instrument (AUTOMATIC DIGITAL HAZEMETER, manufactured by Nippon Densoku Co., Ltd.), and light having a wavelength of 400 to 700 nm in the perpendicular direction of the vertically placed sample was placed. The haze value was measured by permeation.

By comparing this measured haze value with the haze value measured with the polyethylene terephthalate film without an antistatic coating layer, the result of confirming how much the haze value rises because an antistatic coating layer exists is shown in Table 1, "haze." It is shown in the column. The smaller the rise of the haze value, the higher the transparency of the antistatic coating layer.

2. Antistatic

The surface resistance was measured in accordance with JIS K7194 after installing the sample under the environment of temperature 23 ℃ and relative humidity 65% RH by using an antistatic measuring instrument (Mitsubishi Co., Ltd .; model name MCP-T600 or Advan Test Co., Ltd .; model name R8340A). Measured. On the other hand, when the value of the surface resistivity exceeds 1 × ^{10 8} Ω, it cannot be measured by the MCP-T600. In this case, R8340A was used. Moreover, in order to measure the humidity dependence of electroconductivity, it measured after leaving for 1 hour to 23 degreeC and 30% of the relative humidity. Three measurements each were taken and their average was used.

In addition, after the coating film immediately after the production was stored for 14 days with the antistatic coating layer in the constant temperature room at 23 ° C. and 65% RH, the antistatic property with time was evaluated as follows.

Grade A: Antistatic change with time (0 days, 14 days) is within 10 ¹

Class B: When antistatic properties change over time (0 days, 14 days) within 10 ²

Class C: Antistatic change over time (0 days, 14 days) is more than 10 ²

3. Water resistance

The film was left in running water for 1 minute using tap water, and then dried at 50 ° C. for 10 minutes, and then the antistatic property and appearance were evaluated as follows.

(Circle): When there is no cloudiness and the change of antistatic property is within 10 ¹

X: When turbidity occurs or a change in antistatic property occurs more than 10 ¹

4. Surface Roughness

According to JIS-B-0601, three-dimensional center line average roughness (SRa) and three-dimensional ten-point average roughness (SRz) were measured using a three-dimensional surface roughness meter KOSAKA SE-3300. It measured 5 times and the average is shown in Table 1.

5. Appearance

The coated surface of the antistatic polyester film was visually observed using various light sources such as fluorescent lamps, halogens, incandescent lamps, and evaluated according to the following criteria.

◎: When appearance defects are not confirmed at all and are excellent appearance quality

(Circle): When a nonuniform defect is slightly recognized but it is a favorable appearance quality.

(Triangle | delta): When the defect in a nonuniformity is confirmed to some extent but is an acceptable appearance quality.

X: When there are many uneven defects and the appearance quality is bad

6. Tape Peeling Force

Nitto Denko tape NO.3 was applied to the surface of the antistatic polyester film using AR1000 (Chem instruments), a peel force measuring instrument, in an atmosphere of 23 ° C ± 3 ° C and 50% RH ± 5% relative humidity. After attaching 31B (thickness: 25 um, width: 25 mm) and immediately squeezing by reciprocating once with a rubber roller of 2 kg load, the peeling force value obtained at this time was measured by peeling 180 degrees at a peeling rate of 0.3 MPM.

division Surface resistance (Ω / □) Surface resistance over time
(14days) Haze
(%) Water resistance Exterior SRa SRz Adhesion RH 65%
(X ₁ ) RH 30%
(X ₂ ) nm nm g / in Example 1 5 x 10 ⁸ 6 x 10 ⁸ A 0.1 ○ ◎ 18 650 1270 Example 2 1 x 10 ⁸ 1 x 10 ⁸ A 0.1 ○ ◎ 17 650 1260 Example 3 3 x 10 ⁸ 3 x 10 ⁸ A 0.1 ○ ◎ 17 650 1120 Example 4 2 x 10 ⁷ 3 x 10 ⁷ A 0.2 ○ ○ 28 780 1230 Example 5 2 x 10 ⁸ 3 x 10 ⁸ A 0.1 ○ ◎ 28 780 1420 Example 6 3 x 10 ⁷ 4 x 10 ⁷ A 0.2 ○ ○ 27 780 1235 Comparative Example 1 8 x 10 ¹² 3 x 10 ¹⁴ A 0.3 ○ △ 18 650 1245 Comparative Example 2 7 x 10 ⁸ 8 x 10 ⁸ B 0.2 ○ ○ 78 900 1250 Comparative Example 3 6 x 10 ⁸ 6 x 10 ⁸ A 0.2 ○ ○ 100 1100 1260 Comparative Example 4 5 x 10 ¹³ 6 x 10 ¹³ B 0.2 ○ △ 28 780 1230 Comparative Example 5 1 x 10 ¹⁴ 2 x 10 ¹⁴ C 0.5 X X 27 780 1080 Comparative Example 6 2 x 10 ¹³ 3 x 10 ¹³ C 0.7 X X 17 650 820

As can be seen from Table 1, the antistatic coating liquid composition and the antistatic polyester film using the same according to an embodiment of the present invention is transparent and excellent antistatic properties, good appearance quality and the antistatic agent of the antistatic layer is dropped or It was confirmed that it exhibits excellent water resistance that does not dissolve, in particular, it has a stable antistatic performance even under low humidity and it can be confirmed that it has a characteristic that is difficult to deteriorate over time.

In addition, it can be seen that the antistatic polyester film according to the embodiment of the present invention satisfies a high acrylate-based commercial tape (NITTO # 31B) and a peel force of 1,000 g / in or more.

Furthermore, the antistatic polyester film according to the embodiment of the present invention can be confirmed that the three-dimensional centerline average roughness (SRa) is excellent in smoothness to less than 50nm.

However, in the case of the film according to Comparative Example 1, as a result of not using the conductive composite (A) containing the π-conjugated conductive polymer and the compound having the structure of Formula 1 according to the present invention, the humidity dependence is large, especially under low humidity. Since the antistatic property is very bad, the desired properties cannot be obtained.

In addition, in the case of the film according to Comparative Example 2 and Comparative Example 3, it can be seen that the smoothness is not very good as the three-dimensional center line average roughness (SRa) is 50nm or more.

In the case of the film according to Comparative Example 4, since the hydrogen ion concentration of the coating liquid is less than 5, it can be seen that aggregation of the coating liquid occurs due to a decrease in stability of the coating liquid.

In addition, in the case of the film according to Comparative Example 5, since no curing agent was used, the antistatic change over time (0 days, 14 days) was found to be 10 ² or more, water resistance was lowered, and many irregular defects were observed, resulting in poor appearance quality. You can see that.

In addition, in the case of the film according to Comparative Example 6, the result of using the curing agent in less than 10% by weight, it can be seen that in all aspects such as antistatic properties, surface resistance time-lapse characteristics, haze, water resistance, coating appearance and adhesion.

As described above, the antistatic coating liquid composition and the antistatic polyester film using the same according to the present invention have good appearance quality, are excellent in transparency and smoothness, and have stable antistatic performance even under low humidity and deteriorate with time. Because it is difficult to prevent dust adsorption and the generation of static electricity, it is difficult to use, so it can be used for magnetic recording materials, electrical insulating materials, insulating tapes, electrical materials, optics, graphics, cards, and transfer arcs. It can be used in a wide range of applications where antistatic properties are required, such as daily use, ribbons, evaporation, packaging, condensers, and various tapes.

In the present specification, only a few examples of various embodiments performed by the present inventors are described, but the technical idea of the present invention is not limited thereto, but may be variously modified and implemented by those skilled in the art.

10: coating layer
20: polyester film

Claims (14)

As antistatic coating liquid composition,
It includes a conductive composite containing a π-conjugated conductive polymer and a compound having a structure of Formula 1, a crosslinking agent, a water-soluble or water-dispersible type binder resin and a dispersibility enhancer,
[Formula 1]

Wherein R _{1 and} R ₂ are each independently a linear or branched alkylene group having 2 to 12 carbon atoms, an alkyl group, an alkenyl group, a vinyl group, an allyl group, a phenyl group, an aryl group, and B ⁺ is a cation,
The coating liquid composition is adjusted by the dispersibility enhancer to adjust the hydrogen ion concentration to satisfy the following equation 1,
[Equation 1]
5 ≤ Z ≤ 12
Where Z is the hydrogen ion concentration of the coating liquid composition
The dispersibility improving agent is a hydroxyl group-containing compound, characterized in that the antistatic coating liquid composition. The method of claim 1,
The compound having the structure of Formula 1 is 3-sulfopropyl acrylate potassium salt, characterized in that, antistatic coating liquid composition. The method of claim 1,
The conductive composite is an antistatic coating liquid composition, characterized in that it comprises 0.1 parts by weight to 6 parts by weight of solids having the structure of Formula 1 per 1 part by weight of the π-conjugated conductive polymer. The method of claim 1,
The conductive composite is an antistatic coating liquid composition, characterized in that the aqueous dispersion containing a polythiophene or a derivative thereof as a compound having the structure of Formula 1 and π-conjugated conductive polymer. The method of claim 1,
The crosslinking agent is at least one selected from the group consisting of carbodimide compounds, isocyanate compounds, oxazoline compounds, melamine compounds and epoxy compounds, antistatic coating liquid composition. The method of claim 1,
The crosslinking agent has a molecular weight of 1,000 or less, antistatic coating liquid composition. The method of claim 1,
The crosslinking agent contains 10 to 85% by weight based on the total weight of the coating liquid composition, antistatic coating liquid composition. The method of claim 1,
The binder resin is a thermoplastic resin having a hydrophilic group, antistatic coating liquid composition. The method of claim 1,
The binder resin, characterized in that 10 to 1000 parts by weight based on 100 parts by weight of the conductive composite, antistatic coating liquid composition. delete The method of claim 1,
The coating liquid composition further comprises 0.002 to 10 parts by weight of the surfactant as a solid with respect to 100 weight of the coating liquid composition, antistatic coating liquid composition. The method of claim 11,
The surfactant is an acetylene diol-based surfactant, characterized in that the antistatic coating liquid composition. delete Claims 1 to 9, 11 and 12 comprising a coating layer applied to the polyester film and the antistatic coating liquid composition according to any one of at least one side of the polyester film,
Satisfy all of the following Equations 2 to 5,
[Equation 2]
X ₁ <10 ¹¹ ,
[Equation 3]
X ₂ <10 ¹¹ ,
[Equation 4]
ㅣ Log X ₁ -LogX ₂ ㅣ <1
[Equation 5]
5 ≤ Y ≤ 50
Where X ₁ and X ₂ (Ω / sq) are the surface resistances of the coating layer at a temperature of 23 ° C. and 65% RH and a temperature of 23 ° C. and 30% RH, respectively, and Y is a three-dimensional surface of at least one side of the film. An antistatic polyester film, characterized by a centerline average roughness.

Images