KR100718848B1 - Anti-static polyester film - Google Patents

Abstract

The present invention forms an antistatic layer comprising a conductive polymer on at least one surface of the polyester film, and forms a silicone resin layer on the upper layer of the antistatic layer to provide a polyester film having excellent antistatic property and mold release property.

The antistatic polyester release film according to the present invention, when used as a release film of various displays, due to the excellent antistatic function is less peeling charge at the time of peeling off the adhesive and eliminates defects due to static electricity generated during peeling Can be. Moreover, also when laminating | stacking a silicone resin layer, it exhibits stable mold release property, without deteriorating an antistatic function.

Polyester release film, conductive polymer, silicone resin layer, antistatic, release property

Description

Antistatic Polyester Film {ANTI-STATIC POLYESTER FILM}

The present invention relates to an antistatic polyester film, and more particularly, to form an antistatic layer comprising a conductive polymer on at least one surface of the polyester film, and to form a silicone resin layer on the upper layer of the antistatic layer, The present invention relates to a polyester film having improved release properties.

With the development of industrialization, the use of synthetic resins or synthetic fibers in many fields, ranging from various electronic and electrical devices, information and communication fields, and general household goods, has raised the problem of static electricity. Recently, such an antistatic function is required in a release film whose main purpose is to protect the adhesive layer. Conventionally, in order to solve the problem caused by static electricity generated when the release film is separated from the adhesive layer, an antistatic function is given to the adhesive layer. However, when the antistatic function is imparted to the pressure-sensitive adhesive layer, there is a problem in that the compatibility of the antistatic agent and the pressure sensitive adhesive is not good enough to show sufficient antistatic property. Therefore, in recent years, in addition to the pressure-sensitive adhesive layer, there have been many cases of providing an antistatic function to the release preventing layer.

On the other hand, the physical properties required for the release film is required to improve the release properties such as release peeling force, solvent resistance, non-transferability of silicon in addition to the antistatic function. In the case of the release peeling force, this is referred to in the manufacture of the pressure-sensitive adhesive, but in the case of the release preventing layer, since the peeling force from the pressure-sensitive adhesive layer should be good, it is generally advantageous to have a low release peeling force. On the other hand, if the silicone contained in the release film is not non-transferring, the silicone component may be transferred to the pressure-sensitive adhesive layer to reduce the function of the pressure-sensitive adhesive. This is because solvent resistance may lower the function of the adhesive while the silicone layer is separated by the solvent used for the adhesive in the step of laminating the release film with the adhesive.

Conventionally, a method of coating a surface of an antistatic film with a silicon coating or preparing a release film having an antistatic function or including a metal material such as lithium, copper, magnesium, calcium, iron, cobalt or nickel in a silicone composition is known. (US Pat. No. 4,764,564). However, the method is not only economically disadvantageous, but also has a limitation in that the silicone can sufficiently perform performance in the release film.

In addition, in the case of a composition in which a silicone resin and an antistatic resin are mixed together, nitrogen, phosphorus, and sulfur compounds contained in the antistatic resin interfere with the curing of the silicone resin, thereby making it difficult to obtain a release film. In addition, in the case of silicone coating on the surface of surfactant, anionic or cationic polymer type antistatic coating, it is common that the antistatic agent to be used exhibits antistatic function depending on the humidity in the air. The silicone coating film causes the antistatic function to deteriorate. In particular, in the case of the surfactant type, the adhesion between the antistatic layer and the silicon layer is lowered, so that the silicon is transferred to the pressure-sensitive adhesive surface, thereby lowering the function of the pressure-sensitive adhesive.

In order to overcome the above-mentioned problems, an object of the present invention is to prevent an antistatic effect even when forming a silicone resin layer on the upper layer of the antistatic layer, an antistatic polyester film having an antistatic layer having improved release properties To provide.

For solving the technical problem as described above, the antistatic polyester film according to an aspect of the present invention, a polyester film, a conductive polymer for the antistatic, is formed on one side or both sides of the polyester film It includes a silicone resin layer laminated on the antistatic layer to improve the antistatic layer and release properties.

The antistatic layer includes a conductive polymer, a binder resin and a crosslinking agent, and more preferably, the antistatic layer includes 200 to 2,000 parts by weight of the binder resin and 40 to 100 parts by weight of the crosslinking agent based on 100 parts by weight of the conductive polymer.

The conductive polymer is preferably prepared by polymerizing polyanions with polythiophene or derivatives thereof.

The binder resin preferably contains at least one functional group selected from the group consisting of carbonyl group, hydroxyl group, acrylic group, urethane group, carboxyl group, amide group, imide group, carboxylic acid, maleic acid and maleic anhydride.

The crosslinking agent preferably includes at least one compound selected from the group consisting of isocyanate, carbonylimide, oxazoline, epoxy and melamine.

The antistatic layer preferably contains 0.5 to 10% by weight of solids.

The silicone resin contained in the silicone resin layer preferably includes an alkylvinyl polysiloxane, an alkylhydrogen polysiloxane, a platinum compound and a silane coupling agent.

The silicone resin layer preferably contains 0.5 to 5.0% by weight of solids.

The thickness of the said polyester film becomes like this. Preferably it consists of 5-300 micrometers.

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

An antistatic polyester film according to an aspect of the present invention, the polyester film, including an electrically conductive polymer for antistatic, the antistatic layer formed on one or both sides of the polyester film to improve the release properties It includes a silicone resin layer laminated on the antistatic layer.

First, the antistatic layer will be described.

The antistatic layer of the present invention is to prevent the generation of static electricity of the polyester film, preferably the antistatic layer comprises a conductive polymer, a binder resin and a crosslinking agent, more preferably the antistatic layer is 100 parts by weight of the conductive polymer 200 to 2,000 parts by weight of the binder resin and 40 to 100 parts by weight of the crosslinking agent.

Specifically, the conductive polymer resin included in the antistatic layer is preferably used by mixing polythiophene or a derivative thereof with polyanion in order to impart antistatic properties. Specifically, the compound represented by the following general formula (1) and the following general formula (2) can be obtained by polymerizing alone or in the presence of a polyanion.

In the general formula 1, R1, R2 each independently represent an aliphatic hydrocarbon group, alicyclic hydrocarbon group or aromatic hydrocarbon group of a hydrogen atom, C _{1 ~ 12} Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and Benzene groups and the like.

In Formula 2, n is an integer of 1 to 4.

The said polyanion is an acidic polymer, and is high molecular carboxylic acid, high molecular sulfonic acid, polyvinyl sulfonic acid, etc. The polymer carboxylic acid includes polyacrylic acid, polymethacrylic acid, polymaleic acid, and the like, and the polymer sulfonic acid includes polystyrene sulfonic acid.

Meanwhile, in the present invention, an aqueous dispersion (Baytron P, Bayer) containing 0.5 wt% of poly (3,4-ethylenedioxythiophene) and 0.8 wt% of polystyrenesulfonic acid (molecular weight Mn = 150,000) is used.

The binder resin included in the antistatic layer improves the adhesion between the antistatic layer and the polyester film as the base film as a water dispersion or water-soluble binder resin, and 200 to 2000 parts by weight is added to 100 parts by weight of the conductive polymer resin. If the content of the binder resin is less than 200 parts by weight, there is a problem in providing adhesion with the substrate, and if it exceeds 2000 parts by weight, there is a problem in implementing transparency and antistatic properties.

The binder resin includes at least one functional group selected from the group consisting of carbonyl group, hydroxyl group, acrylic group, urethane group, carboxyl group, amide group, imide group, carboxylic acid, maleic acid and maleic anhydride. As the binder resin including the functional group, at least one of polyacrylic, polyurethane, epoxy, polyester, vinyl resin, and amide resin may be used. Each of the compounds may have a substantially complex structure by copolymerization, and examples of the binder having a composite structure include acrylic graft polyester, acrylic graft polyurethane, vinyl resin graft polyester, and vinyl resin graft. Polyurethane and the like.

The crosslinking agent included in the antistatic layer is used to improve the adhesion between the coating layer of the antistatic layer and the polyester film, which is a base film, and is preferably an isocyanate type, carbonylimide type, oxazoline type, and melamine type compound. Any one or more selected from the group consisting of is used. In addition, 40 to 400 parts by weight of the crosslinking agent is added with respect to 100 parts by weight of the conductive polymer resin, and if it is added below 40 parts by weight, sufficient curing is not achieved, so it is difficult to realize adhesion, and when it exceeds 400 parts by weight, transparency is inhibited. .

The antistatic layer is coated with a polyester film after dilution with a solvent so that a solid content of 0.5 to 10.0% based on the total weight. The solvent is not limited as long as it can be applied to the polyester film by dissolving the solid content of the present invention, but preferably water is used. On the other hand, if the content of the solid content is less than 0.5% by weight, there is a problem that the film formation of the coating layer and the expression of the antistatic function is not sufficient, when the content of more than 10.0% by weight there is a problem that the transparency of the film is lowered.

Next, a silicone resin layer is demonstrated.

The silicone resin layer is not limited as long as it is formed on the antistatic layer to improve the release property, but the silicone resin layer used in the present invention includes an alkylvinylpolysiloxane, an alkylhydrogenpolysiloxane, a platinum compound and a silane coupling agent. do. More specifically, 1.5 to 10 parts by weight of alkylhydrogenpolysiloxane is added to 100 parts by weight of alkylvinylpolysiloxane, preferably 2 to 5 parts by weight. The platinum complex is 10 to 500 ppm based on 100 parts by weight of the alkylvinylpolysiloxane. The silane coupling agent is 0.5 to 30 parts by weight based on 100 parts by weight of the alkylvinylpolysiloxane.

The silane coupling agent is preferably an amino silane system, a vinyl silane system, an epoxy silane system, a methacryloxy silane system, an isocyanate silane system, or the like, and more preferably an epoxy silane coupling agent.

The silicone resin layer of the present invention is diluted with a solvent so as to contain 0.5 to 10.0% solids relative to the total weight of the solvent and then coated on a polyester film. If it is 0.5% or less, sufficient release force may not be expressed, and if it is 10% or more, transparency may be poor and it may cause a change over time in silicone curing. The solvent is not limited as long as it can be applied on the antistatic layer by dissolving the solid content, but is preferably any one selected from the group consisting of methanol, ethanol, methyl ethyl ketone, toluene, normal hexane, ethyl acetate and the like. Use more than one.

The silicone resin used in the present invention is applied to the substrate in the form of an emulsion or in the form of a dispersed phase, and the dispersion may further add an aqueous polymer such as polyethylene glycol or polyvinyl alcohol and a surfactant such as alkylphenylpolyglycol ether.

Next, a polyester film is demonstrated.

The polyester film used in the present invention is not limited in kind, but a known one conventionally known as a base film of an antistatic coating can be used. Although the present invention will be described with reference to polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, the polyester film of the present invention is not limited thereto. The polyester which comprises the said film points out the polyester obtained by polycondensing aromatic dicarboxylic acid and aliphatic glycol. As aromatic dicarboxylic acid, terephthalic acid, 2, 6- naphthalenedicarboxylic acid, etc. are mentioned, As aliphatic glycol, ethylene glycol, diethylene glycol, 1, 4- cyclohexane dimethanol, etc. are mentioned. Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6- and phthalenedicarboxylate (PEN). The said polyester can also be a copolymer containing a 3rd component. Examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (for example, P-oxybenzoic acid). Examples thereof include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentylglycol, and the like. These dicarboxylic acid components and glycol components may use 2 or more types together. The film of this invention uses the uniaxial or biaxial oriented film which has high transparency and is excellent in productivity and workability.

The polyester film which is the said base film can be manufactured by a well-known method. After vacuum drying the polyester resin, the extruder was melted by an extruder, extruded into a sheet through T-DIE, adhered to a casting drum by pinning on a cooling roll, and solidified by cooling to obtain an unstretched polyester sheet. In the transverse stretching apparatus which performs longitudinal stretching 2.5-4.5 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 mechanically stretches the film bitten by a clip continuously. A stretching orientation film can be obtained by extending | stretching and heat setting 3.0-7.0 times at. The coating method performed between the longitudinal stretching process and the transverse stretching process is not particularly limited, but may be a meyer bar method, a gravure method, or the like. Corona discharge treatment is preferred to improve the adhesion and coating properties of the. In addition, ethers such as ethanol, isopropanol and isopropyl alcohol, ethyl cellosolve, t- butyl cellosolve and the like for improving stability, wetting and coating leveling of the antistatic coating solution , Ketones such as methyl ethyl ketone, acetone, amines such as dimethylethanolamine, or ionic / nonionic surfactants can be used in combination. The thickness of the said polyester film is 5-300 micrometers normally, Preferably it is 10-250 micrometers.

The antistatic layer formed on the base film is formed by applying a coating liquid diluted with water to a conductive polymer resin, a binder resin and a crosslinking agent on at least one side of the base film. As a coating method of the coating composition, a coating method using a roll such as a gravure roll or a reverse gravure roll, a coating method using a mayer bar, or an air knife General methods such as coating method can be used, and before applying, corona discharge treatment is applied to the surface of the film to increase polar group introduction and surface tension, so that the coating property of the composition is advantageous and the adhesion between the composition and the polyester resin is improved. desirable.

The silicone resin layer described above is laminated on the antistatic layer laminated on at least one side of the base film. The lamination method of the silicone resin layer is the same as the lamination method of the antistatic layer, but preferably, a polyester release film having excellent antistatic property is prepared by hot-air drying after coating by a gravure coating method.

The antistatic layer of the present invention, unlike the mechanism that implements the antistatic function by the ionic bond with the moisture of the atmosphere of the general ion type antistatic agent, due to the implementation of the antistatic effect by the mechanism by the electron conduction of the conductive polymer Even if the silicone resin layer is applied to the top of the antistatic layer has an effect that the antistatic property is maintained.

Hereinafter, the present invention will be described in more detail with reference to Examples. 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.

< Manufacture example 1>

Preparation of Polyester Film Substrate

Polyethylene terephthalate pellets having an ultimate viscosity of 0.625 µg / g containing 20 ppm of amorphous spherical silica particles having an average particle diameter of 2.5 µm were sufficiently dried at 160 ° C. for 7 hours using a vacuum dryer, and then melted and extruded. By contacting the cooling drum through the electrostatic application method through to form an amorphous non-stretched sheet, it was heated again and stretched 3.5 times in the film advancing direction at 95 ℃. Next, a corona discharge treatment was performed on the surface of the film to be coated to prepare a polyester film.

< Example  1>

100 parts by weight of a conductive polymer resin (Bayer, Baytron P; an aqueous dispersion containing 0.5% by weight of poly3,4-ethylenedioxythiophene and 0.8% by weight of polystyrenesulfonic acid) as a solid on the corona-treated side, and an acrylic binder resin 400 parts by weight of Nippon Carbide, Y8003B, and 100 parts by weight of an epoxy crosslinking agent (Nagase Chemtech Co., Ltd., DENACOL EX-313) were mixed with water to prepare an antistatic coating solution. At this time, the content of the solid content was to contain 2.0% by weight based on the total antistatic coating liquid. The antistatic coating solution was applied to the polyester film of the preparation using the # 8 Meyer bar. After coating, the coating liquid applied in the 100 ~ 130 ℃ tender section was dried, stretched 3.5 times in the direction perpendicular to the traveling direction of the film and heat-treated at 240 ℃ for 4 seconds to obtain a biaxially stretched antistatic polyester film having a thickness of 25 ㎛.

100 parts by weight of a silicone resin (Dow Corning, SYL-OFF SD 7226), 1 part by weight of anchorage additive (Dow Corning, SYL-OFF Sl 9250) and 1 part by weight of platinum catalyst (Dow Corning, 4000cat) on the surface on which the antistatic layer is formed 1900 parts by weight of a dilute solvent consisting of and hexane was mixed, and the total solid content was diluted to 1.5% by weight and then applied using a gravure coater. After the coating was dried and cured in a 70 ~ 150 ℃ section to obtain a final polyester release film.

< Example  2>

In the step of manufacturing the antistatic layer, 100 parts by weight of the conductive polymer resin (Bayer, Baytron P) based on solids, 500 parts by weight of the urethane binder resin (Japan Nippon Ink Chemical, AP-40F), melamine crosslinking agent (Cytek, CYMEL385) A polyester release film was prepared in the same manner as in Example 1, except that 150 parts by weight of water was mixed to dilute the total solid content to 2.5% by weight.

< Example  3>

In the manufacturing step of the antistatic layer, 100 parts by weight of conductive polymer resin (Bayer, Baytron P) based on solids, 400 parts by weight of polyester resin (Japan Synthetic, WOO30), epoxy crosslinking agent (Nagase Chemtech, DENACOL EX-313) A polyester release film was prepared in the same manner as in Example 1, except that 100 parts by weight of water was mixed to dilute the total solid content to 2.5% by weight.

< Comparative example  1>

In the step of preparing the antistatic layer, 100 parts by weight of a quaternary ammonium antistatic agent (Cystat, CYSTAT®609), 300 parts by weight of a urethane binder resin (Japan Nippon Chemical Co., AP-40F), melamine without addition of a conductive polymer resin A polyester release film was prepared in the same manner as in Example 1, except that 50 parts by weight of a crosslinking agent (CYMEL385) was mixed with water to prepare a dilute solution having a total solid content of 2.0 wt%.

< Comparative example  2>

In the manufacturing step of the antistatic layer, without adding the conductive polymer resin, 100 parts by weight of quaternary ammonium antistatic agent (Japan oil company, Eregan 264-A), 200 parts by weight of acrylic resin (Nippon Carbide, Y8003B), epoxy crosslinking agent (Nagase Chemtech Co., DENACOL EX-313) A polyester release film was prepared in the same manner as in Example 1, except that 50 parts by weight of water was mixed and diluted to 2.0 wt% of the total solid content. It was.

Physical properties of the biaxially oriented films prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were evaluated in the following manners, and the results are shown in Table 1 below.

1. Antistatic

The surface resistance was measured in accordance with JIS K7194 after the sample was installed in an environment of temperature 23 ° C. and humidity 50% RH using an antistatic measuring instrument (Mitsubishi Co., Ltd .; model name MCP-T600).

2. Transparency ( Haze )

A sample of 10 cm x 10 cm sample was placed vertically in an HAITMATIC DIGITAL HAZEMETER (manufactured by Nippon Densoku Co., Ltd.) in a vertical position, and light was transmitted through light having a wavelength of 400 to 700 nm in a direction perpendicular to the vertically placed sample. The value was measured.

At this time, the haze value was calculated by Equation 1 below.

      Haze (%) = (1- amount of scattered light / total transmission of light) × 100

3. Release force

Samples are stored at 25 ° C, 65% RH for 24 hours, and then a standard adhesive tape (TESA7475) is applied to the silicone coated surface. After peeling the sample for 30 minutes under a load of 20 g / cm ² at room temperature (25 ° C.), the peel force was peeled off at an angle of 180 ° at a rate of 12 in / min using a peel force measuring instrument (cheminstrument AR-1000). Measured. Peel force unit is g / in and the measured value was measured five times to represent the average value.

4. Residual adhesion rate

After preserving the sample at 25 ° C. and 65% RH for 24 hours, a standard adhesive tape (Nitto 31B) was attached to the silicon coated surface and pressed at room temperature under a load of 20 g / cm ² for 24 hours. The surface is flat and clean after collection without contamination After adhering to the PET film surface, it is reciprocally compressed three times with a tape roller of 2 kg (ASTMD-1000-55T). Then, the peel force was measured while peeling at an angle of 180 ° using a peel force measuring instrument (cheminstrument AR-1000) at a rate of 12 in / min. At this time, the residual adhesion rate value was calculated by the following equation (2).

Residual Adhesion (%) = adhered to silicone surface Peeling force of peeled adhesive tape / Peeling force of adhesive tape not in contact with silicon surface * 100

5. Solvent resistance

It carried out to measure the resistance to the solvent of the film surface. The measurement was performed by soaking ethanol in a cotton swab and maintaining the angle of the cotton swab at 45 degrees while reciprocating the coated film surface 10 times at a rate of 5 cm / sec with a load of 100 g at a rate of 5 cm / sec. Evaluation was made based on the criteria.

○: little change in antistatic properties and no scratches

X: When the antistatic property is lost or the coating surface is peeled off

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Surface resistance (Ω / sq) 10 ⁵ (10 ⁴ ) 10 ⁶ (10 ⁴ ) 10 ⁵ (10 ⁴ ) 10 ¹⁵ (10 ¹¹ ) 10 ¹⁶ (10 ¹¹ ) Transparency (%) 1.35 1.13 1.07 1.84 2.20 Release peel force (g / in) 9.2 11.2 9.8 11.4 10.5 Residual adhesion rate (%) 95 96 95 96 95 Solvent Resistance (TOL) ○ ○ ○ × × Solvent resistance (MEK) ○ ○ ○ × ×

Values in parentheses among the surface resistance item values in Table 1 refer to surface resistance values of the antistatic coating surface before forming the silicone resin layer, and values outside parentheses represent surface resistance values after forming the silicone resin layer. Solvent resistance (TOL) is a measure of solvent resistance to toluene and solvent resistance (MEK) is a measure of solvent resistance to methyl ethyl ketone.

As can be seen in Table 1, it can be seen that in the case of the conventional humidity-dependent antistatic layer as in Comparative Examples 1 and 2, the antistatic function is reduced due to the silicon film, and in the case of the conductive resin, it is stable and excellent charging with release properties. It can be seen that it can have a protection function.

The antistatic polyester release film according to the present invention, when used as a release film of various displays, due to the excellent antistatic function is less peeling charge at the time of peeling with the adhesive and eliminate the defects due to static electricity generated during peeling Can be. Moreover, also when laminating | stacking a silicone resin layer, it exhibits stable mold release property, without deteriorating an antistatic function.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such modifications and modifications belong to the appended claims.

Claims (13)

delete delete delete delete delete delete delete delete delete delete In the method for producing a polyester release film, Contacting the polyester film by electrostatic application to prepare an unstretched microcrystalline film; Preparing a uniaxially stretched film by stretching the unstretched microcrystalline film 2.5 to 4.5 times in a longitudinal direction; Any one selected from the group consisting of a conductive polymer polymerized with a polyanion and a polythiophene or a derivative thereof, and a carbonyl group, a hydroxyl group, an acryl group, a urethane group, a carboxyl group, an amide group, an imide group, a carboxylic acid, maleic acid and maleic anhydride Binder resin containing the above functional group and any one or more crosslinking agents selected from the group consisting of isocyanate, carbonylimide, oxazoline, epoxy and melamine, and the binder resin with respect to 100 parts by weight of the conductive polymer Coating an antistatic coating liquid consisting of 200 to 2,000 parts by weight and 40 to 100 parts by weight of a crosslinking agent on one or both surfaces of the uniaxial stretched film; Preparing a biaxially stretched film by stretching the coated monoaxially stretched film in a lateral direction by 3.0 to 7.0 times; At least one silicone resin selected from the group consisting of alkylvinyl polysiloxanes, alkylhydrogen polysiloxanes, platinum complexes, and silane coupling agents, wherein the silicone resin is contained as a solid content of 0.5 to 5% by weight based on the total release coating solution. Coating a release coating solution on a surface treated with an antistatic coating solution in the biaxially stretched film; a method of manufacturing a polyester release film, characterized in that the composition comprises a. The method of claim 11, The antistatic coating solution is a method for producing a polyester release film, characterized in that it contains 0.5 to 10% by weight solids. The method of claim 11, The thickness of the said polyester film is 5-300 micrometers, The manufacturing method of the said polyester release film characterized by the above-mentioned.