JP2007152930A - Anti-static polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-static polyester film having an anti-static layer capable of enhancing a mold-releasing property without deteriorating the anti-static effect even in a case of forming a silicone resin layer on the upper surface of the anti-static layer. <P>SOLUTION: The mold-releasing polyester film has an anti-static coating layer containing a polyester film and a conductive polymer for preventing the anti-static property and formed on one surface or both surfaces of the polyester film, and a silicone resin layer laminated on the anti-static layer to enhance the mold-releasability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antistatic polyester film. More specifically, an antistatic layer containing a conductive polymer is formed on at least one surface of a polyester film, and a silicon resin layer is formed on the antistatic layer to form a charge. The present invention relates to a polyester film with improved prevention and release properties.

  With the development of industrialization, as the use of synthetic resins or synthetic fibers rapidly increases in various fields ranging from various electronic and electrical devices, information and communication fields, and general household goods, the problem of static electricity has been greatly increased. Recently, many such antistatic functions are also required for release films 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 pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer has been provided with an antistatic function. However, when an antistatic function is imparted to the pressure-sensitive adhesive layer, there is a problem that the compatibility between the antistatic agent and the pressure-sensitive adhesive is not good and the antistatic property is not sufficiently exhibited. Therefore, recently, in addition to the pressure-sensitive adhesive layer, an antistatic function is often given to the release prevention layer.

  On the other hand, in addition to the antistatic function, the physical properties required for the release film are required to improve the release properties such as the release force, solvent resistance, and non-transferability of silicon. The mold release force is referred to during the production of the pressure-sensitive adhesive, but the release force from the pressure-sensitive adhesive layer should be good also in the case of the mold release preventing layer, and generally has a low mold release force. preferable. On the other hand, when the silicon contained in the release film is not non-transferable, the silicon component can be transferred to the pressure-sensitive adhesive layer and the function of the pressure-sensitive adhesive can be reduced. The solvent resistance is that the silicon layer is separated by the solvent used for the adhesive in the process of interleaving the release film with the adhesive, and this separated silicon adheres to the adhesive surface and reduces the function of the adhesive. There is also.

  Conventionally, in order to produce a release film having an antistatic function, the surface of the static elimination film is coated with silicon, or a metal material such as lithium, copper, magnesium, calcium, iron, cobalt or nickel is added to the silicon composition. The method of making it contain was performed (for example, patent document 1). However, the above method is not only economically disadvantageous, but also has a limit for the silicon to exhibit sufficient performance in the release film.

In the case of a composition in which a silicone resin and an antistatic resin are mixed, nitrogen, phosphorus and sulfur compounds contained in the antistatic resin interfere with the curing of the silicone resin, making it difficult to obtain a release film. It was. Furthermore, when a silicone coating is applied to a surface active agent or an anionic or cationic polymer type antistatic coating surface, the antistatic agent used generally exhibits an antistatic function depending on the humidity in the atmosphere. The antistatic function is lowered by the silicon coating film on the antistatic layer. In particular, in the case of the surfactant type, there is a problem in that the adhesion between the antistatic layer and the silicon layer is reduced and silicon is transferred to the pressure-sensitive adhesive surface, thereby reducing the function of the pressure-sensitive adhesive.
US Patent Publication No. 4,764,564.

  In order to overcome the above-mentioned problems, the object of the present invention is to provide an antistatic layer that improves the release properties without deteriorating the antistatic effect even when a silicon resin layer is formed on the antistatic layer. It is in providing the antistatic polyester film provided.

  In order to achieve the above object, a polyester release film according to the present invention includes a polyester film, and an antistatic coating layer formed on one or both sides of the polyester film, including a conductive polymer for antistatic, A silicon resin layer laminated on the antistatic layer in order to improve release properties.

  The antistatic layer includes a conductive polymer, a binder resin, and a crosslinking agent, and the antistatic layer includes 200 to 2,000 parts by weight of a binder resin and 40 to 100 parts by weight of a crosslinking agent with respect to 100 parts by weight of the conductive polymer. It is preferable to contain.

  The conductive polymer is preferably produced by polymerizing a polyanion and polythiophene or a derivative thereof.

  The binder resin contains one or more functional groups 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. It is preferable.

  The cross-linking agent preferably contains any one or more compounds selected from the group consisting of isocyanate, carbonylimide, oxazoline, epoxy, and melamine.

  The antistatic layer preferably contains a solid content of 0.5 to 10% by weight.

  The silicon resin contained in the silicon resin layer preferably contains an alkyl vinyl polysiloxane, an alkyl hydrogen polysiloxane, a platinum complex compound, and a silane coupling agent.

  The silicon resin layer preferably contains a solid content of 0.5 to 5.0% by weight.

  The polyester film preferably has a thickness of 5 to 300 μm.

  The antistatic polyester release film according to the present invention, when used as a release film for various displays, has an excellent antistatic function so that there is little peeling charge at the time of peeling from the adhesive and can eliminate defects caused by static electricity generated at the time of peeling. . In addition, when a silicon resin layer is laminated, stable release properties are exhibited without deteriorating the antistatic function.

  The present invention will be described in detail below.

  The antistatic polyester film according to the present invention includes a polyester film, a conductive polymer for antistatic, and in order to improve the antistatic layer formed on one or both sides of the polyester film and the release physical properties, A silicon resin layer laminated on the antistatic layer;

  First, the antistatic layer will be described.

  The antistatic layer of the present invention is for preventing the generation of static electricity in the polyester film, and the antistatic layer preferably contains a conductive polymer, a binder resin and a cross-linking agent. It is preferable that 200 to 2,000 parts by weight of a binder resin and 40 to 100 parts by weight of a crosslinking agent are included with respect to 100 parts by weight of the conductive polymer.

  The conductive polymer resin contained in the antistatic layer is used by mixing polythiophene or a derivative thereof with polyanion in order to impart antistatic properties. Specifically, the compounds represented by the following general formula 1 (Chemical formula 1) and general formula 2 (Chemical formula 2) can be obtained individually or mixed and polymerized in the presence of a polyanion.

In the above general formula 1, R ₁ and R ₂ represent a hydrogen atom, a C _1-12 aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, respectively. , Methyl group, ethyl group, propyl group, isopropyl group, butyl group, benzene group, and the like.

  In the above general formula 2, n is an integer of 1 to 4.

  The poly anion is an acidic polymer, such as a high-molecular carboxylic acid, high-molecular sulfonic acid, or polyvinyl sulfonic acid. Examples of the polymeric carboxylic acid include polyacrylic acid, polymethacrylic acid, and polymaleic acid. Examples of the polymeric sulfonic acid include polystyrene sulfonic acid.

  On the other hand, in the present invention, an aqueous dispersion (Baytron) of a polymer containing 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrenesulfonic acid (molecular weight Mn = 150,000). P, Bayer).

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

  The binder resin has 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. Including. As the binder resin containing the functional group, one or more of polyacrylic, polyurethane, epoxy, polyester, vinyl resin and amide resin can be used. Each of the compounds has a substantially complex structure due to copolymerization or the like in each skeleton structure. Examples of the binder having the complex structure include acrylic graft polyester, acrylic graft polyurethane, vinyl resin graft polyester, and vinyl resin graft polyurethane. is there.

  The crosslinking agent contained in the antistatic layer is used to improve the adhesion between the coating layer of the antistatic layer and the polyester film as the base film, and is based on isocyanate, carbonylimide, oxazoline and melamine. It is preferable to use any one or more selected from the group consisting of series compounds. Further, 40 to 400 parts by weight of the crosslinking agent is added to 100 parts by weight of the conductive polymer resin. In addition, when the addition amount is less than 40 parts by weight, sufficient curing is not performed and it is difficult to realize adhesion, and when it exceeds 400 parts by weight, transparency is hindered.

  The antistatic layer is coated with a polyester film after being diluted with a solvent so that the solid content is 0.5 to 10.0% based on the total weight. The solvent is not particularly limited as long as it can dissolve the solid content of the present invention and can be applied onto the polyester film, but it is preferable to use water. When the solid content is less than 0.5% by weight, there is a problem that the coating layer is not sufficiently formed and the antistatic function is not sufficiently exhibited. There is a problem that the performance is lowered.

  Next, the silicon resin layer will be described.

  The type of the silicone resin layer is not limited as long as it can be formed on the antistatic layer and can improve the release properties. However, the silicone resin layer used in the present invention is an alkyl vinyl polysiloxane or an alkyl hydrogen polysiloxane. A platinum complex compound and a silane coupling agent. More specifically, the alkyl hydrogen polysiloxane is added in an amount of 1.5 to 10 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the alkyl vinyl polysiloxane. The platinum complex compound is 10 to 500 ppm based on 100 parts by weight of the alkyl vinyl polysiloxane. The silane coupling agent is 0.5 to 30 parts by weight with respect to 100 parts by weight of the alkyl vinyl polysiloxane.

  As the silane coupling agent, amino silane, vinyl silane, epoxy silane, methacryloxy silane, isocyanate silane, or the like is used, and an epoxy silane coupling agent is preferably used.

  The silicon resin layer of the present invention is coated on a polyester film after being diluted with a solvent so that a solid content of 0.5 to 10.0% is contained with respect to the total weight. When it is 0.5% or less, sufficient release force cannot be expressed, and when it is 10% or more, the transparency is poor and a change with time can be induced in silicon curing. The solvent is not particularly limited as long as it can dissolve the solid content and can be applied on the antistatic layer, but any one selected from the group consisting of methanol, ethanol, methyl ethyl ketone, toluene, normal hexane, ethyl acetate, and the like. Or 1 or more.

  The silicone resin used in the present invention is applied to the substrate in the form of an emulsion or dispersed phase, and in the dispersion, an aqueous polymer such as polyethylene glycol or polyvinyl alcohol and a surfactant such as alkylphenyl polyglycol ether are further added. You can also

  Next, the polyester film will be described.

  Although there is no restriction | limiting in the kind in the polyester film used for this invention, What is well-known as a base film of the conventional antistatic coating can be used. In the present invention, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate will be mainly described. However, the polyester film of the present invention is not limited to this. The polyester constituting the film is a polyester obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyesters include polyethylene terephthalate (PET) and polyethylene-2,6-naphthalenedicarboxylate (PEN). The polyester may be a copolymer containing a third component. Examples of the dicarboxylic acid component of the copolymer polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (for example, P-oxybenzoic acid). Examples of the glycol component include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like. Two or more of these dicarboxylic acid components and glycol components may be used in combination. As the film of the present invention, a uniaxial or biaxially oriented film having high transparency and excellent productivity and workability is used.

  The polyester film as the base film can be produced by a known method. The polyester resin is vacuum dried and then melted in an extruder, extruded onto a sheet through a tee die (T-DIE), closely attached to a casting drum by an electrostatic application method (pinning) on a cooling roll, cooled and solidified, and an unstretched polyester sheet Get. In addition, this roll is heated at a temperature higher than the glass transition temperature of the polyester resin, and stretched in the longitudinal direction by 2.5 to 4.5 times depending on the peripheral speed ratio difference between the rolls. A stretched and oriented film can be obtained by stretching and heat-setting the resulting film by 3.0 to 7.0 times in a transverse stretching apparatus that mechanically stretches the film. The coating method performed between the longitudinal stretching process and the transverse stretching process is not particularly limited, but a Mayer bar system, a gravure system, etc. are used, and a polar group is introduced to the film surface before coating. Then, it is preferable to perform corona discharge treatment so as to improve the adhesion and coating properties between the coating layer and the film. Also, in order to improve the safety, wetting and coating leveling of the antistatic coating solution, alcohols such as ethanol, isopropanol and isopropyl alcohol, and ethers such as ethyl cellosolve and t-butyl cellosolve , Ketones such as methyl ethyl ketone and acetone, amines such as dimethylethanolamine, or one or more ionic / nonionic surfactants may be mixed and used. The thickness of the polyester film is usually 5 to 300 μm, preferably 10 to 250 μm.

  The antistatic layer formed on the base film is formed by applying a coating liquid obtained by diluting a conductive polymer resin, a binder resin, and a crosslinking agent with water on at least one surface of the base film. Examples of the coating composition coating method include a coating method using a roll such as a gravure roll and a reverse gravure roll, a coating method using a Mayer bar, an air knife. A general method such as a coating method is used, and a corona discharge treatment is performed before coating, a polar group is introduced to the film surface to increase the surface tension, and the coating property of the composition is improved. It is preferable to improve the adhesive strength with the polyester resin.

  The silicon resin layer is laminated on the antistatic layer laminated on at least one surface of the base film. The method for laminating the silicon resin layer is the same as the method for laminating the antistatic layer, but it is preferable to produce a polyester release film having excellent antistatic properties by coating with a gravure coating method and then drying with hot air.

  The antistatic layer of the present invention is different from the mechanism in which a general ion-type antistatic agent achieves an antistatic function by ionic bonding with moisture in the atmosphere, and has an antistatic effect due to the mechanism of electronic conduction of a conductive polymer. By realizing it, there is an effect that the antistatic property is maintained even if a silicon resin layer is applied to the upper end of the antistatic layer.

  Hereinafter, the present invention will be described in more detail through examples. The present examples specifically illustrate the present invention, and the scope of the present invention is not limited to these examples.

[Production Example 1; Production of polyester film substrate]
After polyethylene terephthalate pellets having an intrinsic viscosity of 0.625 μm / g containing 20 ppm of amorphous spherical silica particles having an average particle diameter of 2.5 μm are sufficiently dried at 160 ° C. for 7 hours using a vacuum dryer. The film was melted at, and adhered to the cooling drum through an extrusion tee die by an electrostatic application method to form an amorphous unstretched sheet, which was heated again and stretched 3.5 times in the film traveling direction at 95 ° C. Next, the film surface to be coated was subjected to corona discharge treatment to produce a polyester film.

[Example 1]
Water dispersion containing conductive polymer resin (Bayer, Baytron P; 0.5% by weight of poly3,4-ethylenedioxythiophene and 0.8% by weight of polystyrene sulfonic acid as solids on the corona-treated surface 100 parts by weight of the body), 400 parts by weight of an acrylic binder resin (Nippon Carbide, Y8003B) and 100 parts by weight of an epoxy crosslinking agent (Nagase Chemtech, DENACOLLEX-313) were mixed with water to produce an antistatic coating solution. At this time, the solid content was 2.0% by weight based on the whole antistatic coating solution. The antistatic coating solution was applied to the polyester film of the production example using a # 8 Mayer bar. After coating, the coating liquid applied in the 100-130 ° C. tender section is dried, stretched 3.5 times in the direction perpendicular to the film traveling direction, heat treated at 240 ° C. for 4 seconds, and biaxially stretched to a thickness of 25 μm. An antistatic polyester film was obtained.

  In the formation surface of the antistatic layer, 100 parts by weight of a silicone resin (Dow Corning, SYL-OFF * SD 7226), 1 part by weight of an anchorage additive (Dow Corning, SYL-OFF * Sl 9250) and a platinum catalyst ( 1 part by weight of Dow Corning Co., Ltd., 4000 cat) was mixed with 1900 parts by weight of a diluent solvent consisting of toluene and hexane, and the total solid content was diluted to 1.5% by weight, followed by coating using a gravure coater. After the coating, the polyester was dried and cured at 70 to 150 ° C. to obtain a final polyester release film.

[Example 2]
In the production stage of the antistatic layer, 100 parts by weight of conductive polymer resin (Bayer, Baytron P), 500 parts by weight of urethane binder resin (Dainippon Ink Chemical, AP-40F) based on solid content, melamine cross-linking agent ( Cytech, CYMEL 385) Polyester release film by the same method as in Example 1 except that 150 parts by weight is mixed with water and the total solid content is diluted to 2.5% by weight. Manufactured.

[Example 3]
In the production stage of the antistatic layer, 100 parts by weight of conductive polymer resin (Bayer, Baytron P), 400 parts by weight of polyester resin (Nippon Gosei, WOO30) based on solid content, epoxy cross-linking agent (Nagase Chemtech, DENACOL EX) -313) A polyester release film is produced by the same method as in Example 1 except that 100 parts by weight is mixed with water and the total solid content is diluted to 2.5% by weight. did.

[Comparative Example 1]
100 parts by weight of quaternary ammonium antistatic agent (Cytech, CYSTAT 609), 300 parts by weight of urethane binder resin (Dainippon Ink Chemical, AP-40F) without adding a conductive polymer resin in the production stage of the antistatic layer The same method as in Example 1 except that 50 parts by weight of a melamine cross-linking agent (Cytech, CYMEL 385) was mixed with water and diluted to a total solid content of 2.0% by weight. A polyester release film was produced.

[Comparative Example 2]
100 parts by weight of quaternary ammonium antistatic agent (Nippon Yushi Co., Ltd., Elegan 264-A), 200 parts by weight of acrylic resin (Nippon Carbide, Y8003B) without adding a conductive polymer resin in the production stage of the antistatic layer , Except that 50 parts by weight of an epoxy crosslinking agent (Nagase Chemtech, DENACOL EX-313) was mixed with water to dilute the total solid content to 2.0% by weight. The method was followed to produce a polyester release film.

  The physical properties of the biaxially stretched films produced in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated by the following methods. The results are shown in Table 1.

<1. Antistatic property>
A sample was placed under an environment of a temperature of 23 ° C. and a humidity of 50% RH using an antistatic measuring machine (Mitsubishi Corporation; model name MCP-T600), and then the surface resistance was measured based on JIS K7194.

<2. Transparency (Haze)>
A sample sampled in a size of 10 cm × 10 cm was placed vertically on a haze measuring machine (AUTOMATIC DIGITAL HAZEMETER, produced by Nippon Denso Co., Ltd., Japan), and 400 to 700 μm in the perpendicular direction of the vertically placed sample. The value shown was measured by transmitting light having a wavelength.

  At this time, the haze value was calculated by the following mathematical formula 1.

Haze (%) = (1− (amount of scattered light / total amount of transmitted light)) × 100 (1)
<3. Release force>
After the sample is stored at 25 ° C. and 65% RH for 24 hours, a standard adhesive tape (TESA7475) is applied to the silicon coating surface. This sample was pressure-bonded at a load of about 1.962 MPa (20 g / cm ² ) for 30 minutes under normal temperature (25 ° C.) conditions, and then 30.48 cm / min (12 in / min) using a peeling force measurement equipment (cheminstrument AR-1000). The peeling force was measured while peeling at an angle of 180 ° at a speed of min). The unit of peeling force was g / in, and the measured value was measured 5 times and the average value was shown.

<4. Residual adhesion rate>
The sample is stored at 25 ° C. and 65% RH for 24 hours, and then a standard adhesive tape (Nitto 31B) is attached to the silicon coating surface, and pressure-bonded at a load of about 1.962 MPa (20 g / cm ² ) at room temperature for 24 hours. After the adhesive tape adhered to the silicon surface is collected without contamination, it is adhered to a clean PET film surface with a flat surface, and is then reciprocated three times with a 2 kg tape roller (ASTMD-1000-55T). Thereafter, the peeling force was measured while peeling at an angle of 180 ° at a speed of 30.48 cm / min (12 in / min) using a peeling force measuring equipment (cheminstrength AR-1000). At this time, the residual adhesion value was calculated by the following mathematical formula 2.

Residual adhesive rate (%) = (“peeling force of the adhesive tape peeled after bonding to the silicon surface” / “peeling force of the adhesive tape not contacting the silicon surface”) × 100 (2)
<5. Solvent resistance>
This was done to measure the resistance of the film surface to the solvent. The measurement was carried out after wetting the cotton swab with ethanol and reciprocating the coated film surface 10 times at a speed of 5 cm / sec with a load of 100 g while maintaining the angle of the swab at 45 degrees. The state of the coating surface was evaluated according to the following criteria. The symbol “O” in the table indicates that there is almost no change in antistatic property and there is no scratched mark, and the symbol “X” indicates that there is no antistatic property or the coating surface is peeled off. To do.

  In Table 1 above, the value in parentheses among the surface resistance item values indicates the surface resistance value of the antistatic coating surface before forming the silicon resin layer, and the value outside the parentheses is after forming the silicon resin layer. The surface resistance value is shown. The value in the parenthesis among the release release force value indicates a value converted in the unit N / cm, and the value outside the parenthesis indicates the value in the unit g / in. The solvent resistance (TOL) is a value obtained by measuring the solvent resistance against toluene, and the solvent resistance (MEK) is a value obtained by measuring the solvent resistance against methyl ethyl ketone.

  As shown in Table 1, in the case of conventional humidity-dependent antistatic layers such as Comparative Examples 1 and 2, it can be seen that the antistatic function is lowered by the silicon coating. In the case of a conductive resin, the release properties are It can also be seen that a stable and excellent antistatic function can be possessed.

  Although the present invention has been described in detail only with respect to the above-described embodiments, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. It goes without saying that it belongs to the appended claims.

Claims (10)

Polyester film,
An antistatic coating layer comprising a conductive polymer for antistatic and formed on one or both sides of the polyester film;
A silicon resin layer laminated on the antistatic layer in order to improve release properties;
An antistatic polyester film comprising:   The antistatic polyester film according to claim 1, wherein the antistatic layer includes a conductive polymer, a binder resin, and a crosslinking agent.   The antistatic polyester film according to claim 2, wherein the antistatic layer comprises 200 to 2,000 parts by weight of a binder resin and 40 to 100 parts by weight of a crosslinking agent with respect to 100 parts by weight of the conductive polymer.   The antistatic polyester film according to any one of claims 1 to 3, wherein the conductive polymer is produced by polymerizing a polyanion and polythiophene or a derivative thereof.   The binder resin contains one or more functional groups 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 antistatic polyester film according to claim 2 or 3, wherein:   The antistatic agent according to claim 2 or 3, wherein the crosslinking agent is one or more compounds selected from the group consisting of isocyanate, carbonylimide, oxazoline, epoxy, and melamine. Polyester film.   The antistatic polyester film according to claim 1, wherein the antistatic layer contains a solid content of 0.5 to 10% by weight.   The antistatic polyester film according to claim 1, wherein the silicone resin contained in the silicone resin layer contains an alkyl vinyl polysiloxane, an alkyl hydrogen polysiloxane, a platinum complex compound, and a silane coupling agent.   The antistatic polyester film according to claim 1 or 8, wherein the silicone resin layer contains a solid content of 0.5 to 5.0% by weight.   The antistatic polyester film according to claim 1, wherein the polyester film has a thickness of 5 to 300 μm.