KR20120077793A - Release film - Google Patents

Abstract

PURPOSE: A release film is provided to prevent generation of static electricity due to low dielectric constant of silicon which comprises the release film. CONSTITUTION: A release film comprises a coating layer spread on one-side of a primer film layer and a polyester based primer film layer. The coating layer is formed by spreading a coating composition which includes the silicon based binder resin and the conductive polymer. The content ratio of the silicon based binder resin to conductive polymer is represented by the following formula: x=weight of the conductive polymer/ (weight of the conductive polymer + silicon based binder resin) * 100 (here, 10 Δ x Δ 15). The coating composition comprises silicon based binder resin, conductive polymer, platinum chelate catalyst and water. The solid content of the coating composition is 1-25 wt%. The silicon based binder resin includes polydimethylsiloxane which is represented by chemical formula 1 and poly(hydrosiloxane) which is represented by chemical formula 2 at a molar ratio of 1:0.5-2. In the chemical formula 1, X indicates an integer of 1-50. In the chemical formula 2, a indicates an integer of 1-50 and b indicates an integer of 1-50.

Description

Release film {Release film}

The present invention relates to a release film used as a temporary support of the adhesive object, and more particularly, to a silicone release composition including an excellent antistatic performance, and excellent antistatic properties prepared by coating it on a polyester base film and a peel force It is related with this excellent polyester release film.

In general, the release film is used as an adhesive surface protection film for pressure-sensitive adhesives, adhesives, adhesives, or the like, or as a carrier sheet for forming a sheet of resin, in detail, a ceramic sheet electrode sheet or the like. Recently, adhesives and adhesives are changing from a liquid state into a sheet form due to diversified uses and varieties of optical products, increased production, and improved productivity. This sheet-shaped release film temporarily protects the adhesive adhesive side of the adhesive article from contamination by dust, debris, moisture and other contaminants until the label is used, for example. In general, the release film is separated from the adhesive side immediately before use of the adhesive article. Therefore, the release film is formed with a coating layer capable of imparting adhesion to the product while providing peelability to the surface of the product.

Such a silicone-coated release film has a problem that the surface of the film is easily charged when friction is applied because the surface resistivity is very large. In this case, foreign matter such as dust adheres to the surface of the film due to static electricity, and electric shock occurs to cause product defects. In order to improve the defects caused by static electricity, antistatic performance is required for the silicone release film.

In order to add an antistatic function, the most commonly used method may be an additive in the form of a surfactant or metal particles. However, when the additive of the surfactant type is applied, when the relative humidity in the air is lowered, not only the antistatic performance is deteriorated but also the peeling force of the release film is increased and the release property is worsened. In addition, when the metal particles are added, the transparency of the film is deteriorated.

The present invention is to provide a release film that at the same time give a release property and antistatic performance for the adhesive surface on one side of the film.

More specifically, there is no change in antistatic performance due to relative humidity in the air, and to provide a release film having a low release force (peel force) when peeling off the adhesive.

More specifically, the present invention evaluates the antistatic performance through the surface resistivity measured according to JIS-K6911 method, wherein the surface resistivity is 1 × 10 ¹¹ Ohm / Sq or less, and the release force measured according to the FINAT 10 Method is To provide a release film of less than 30 gf / inch.

The present invention relates to a silicone release film, characterized in that the release film is applied to protect the adhesive surface, by adding a conductive polymer exhibiting an antistatic effect to the silicone composition at the same time having antistatic properties and mold release properties.

More specifically, the present invention relates to a release film made of a coating layer coated with a coating composition containing a silicone-based binder resin and a conductive polymer on one surface of a polyester base film layer.

More specifically, the content ratio of the silicone-based binder resin and the conductive polymer relates to a release film having a value (x) according to Equation 1 below 10 ≦ x ≦ 15.

[Equation 1]

x = weight of conductive polymer / (weight of conductive polymer + weight of silicone binder resin) × 100

Hereinafter, the present invention will be described more specifically.

In the present invention, the base film is preferably a uniaxial or biaxially stretched polyethylene terephthalate film, and after the surface treatment such as corona treatment for strong chemical bonding between the substrate and the coating layer is applied to the composition of the coating layer of the present invention. Can be. Although the thickness of the base film is not limited, it is preferable to use a 20 to 1500 μm because it is easy to peel off during release.

In the present invention, the coating composition forming the coating layer of the release film may be prepared in an emulsion type or a solvent type according to a coating method or use, and the composition of the emulsion type is mainly applied to in-line coating, and the composition of the solvent type is coated offline. Can be applied to

When using the composition of the emulsion type is environmentally stable, there is an advantage that the workability is improved by applying in-line coating. However, it is not limited thereto.

In the present invention, when the emulsion composition is used, the coating composition specifically includes a silicone-based binder resin, a conductive polymer, a platinum chelate catalyst, and water, and the solid content is preferably 1 to 25% by weight.

In the present invention, when the ratio of the silicone binder resin is increased in the ratio of the silicone binder resin and the conductive polymer, the releasability is excellent, but the conductivity disappears, and when the amount of the conductive polymer is increased, the antistatic property is excellent but the releasability is worsened. do. Through various experiments, the researchers found the optimal conditions to secure satisfactory release property and antistatic property at the same time.

In the present invention, when the content ratio of the silicone-based binder resin and the conductive polymer is used in a range in which the value (x) according to Equation 1 is 10 ≤ x ≤ 15, more excellent antistatic property and release property can be used as a release film. The release film which has at the same time can be provided.

[Equation 1]

x = weight of conductive polymer / (weight of conductive polymer + weight of silicone binder resin) × 100

An antistatic property and a release property required in the release film may be simultaneously satisfied within a range that satisfies Equation 1 above. That is, in the range where the value (x) according to Equation 1 satisfies 10 ≤ x ≤ 15, the antistatic performance measured according to JIS-K6911, that is, the surface resistivity is 1 × 10 ¹¹ Ohm / sq or less, and the FINAT 10 Method According to the present invention, it is possible to provide a release film having a release force of 30 gf / inch or less. When the antistatic performance, that is, the surface resistivity is greater than 1 × 10 ¹¹ Ohm / sq, foreign matters such as dust may occur on the surface of the film, and when the release force is more than 30 gf / inch, high peeling is performed when peeling with the adhesive layer. Force is required, which impairs fairness.

In the present invention, the silicone-based binder resin is used to adjust the molar ratio of polydimethylsiloxane of the formula 1 and polyhydrosiloxane of the formula 2 to 1: 0.5 to 2.0 in order to improve the adhesion between the coating layer and the polyester base film desirable. If the molar ratio is less than 1: 0.5, the adhesiveness may be lowered. If the molar ratio is greater than 1: 2.0, the elasticity or physical properties may be reduced after curing. In addition, when the amount of polyhydrosiloxane is too large compared to the polydimethylsiloxane, crosslinking may proceed too much, resulting in reduced flexibility and cracking of the coating layer, thereby reducing smoothness.

[Formula 1]

(Wherein x is an integer from 1 to 50).

[Formula 2]

(Wherein a is an integer of 1 to 50 and b is an integer of 1 to 50).

It is preferable to use the silicone-based binder resin having a viscosity of 500 ~ 1000cps (25 ℃). The viscosity can be controlled by adjusting the molar ratio or degree of polymerization of the polydimethylsiloxane and polyhydrosiloxane, when the viscosity of the silicone binder resin of the present invention is less than 500cps, there is a fear that the adhesion between the coating layer and the base film is lowered, 1000cps If exceeded, water dispersion may be difficult.

Specifically, the silicone binder resin may be, for example, Waker's Dehesive 430, Dehesive 440, Dowcorning's SYL-OFF 7920, SYL-OFF 7924, etc., but is not limited thereto.

In the present invention, the silicone-based binder resin is preferably used in the range of 1 to 25% by weight of the total coating composition, when less than 1% by weight there is a fear that the adhesion between the base film and the coating layer is lowered, if it exceeds 25% by weight The amount of adhesion is no longer improved, which may lead to waste of unreacted silicone-based binder resin.

The platinum chelate catalyst in the coating composition of the present invention promotes the reactivity of the silicone-based binder resin, ie, the reactivity between the vinyl group of the polydimethylsiloxane of formula 1 and the hydrogen of the polyhydrosiloxane of formula 2, the adhesive line to which the coating layer is adhered to the base film, In other words, it increases the adhesion. Such platinum catalyst is preferably included in 1 ~ 20ppm, if less than 1ppm does not increase the reactivity improvement effect, if exceeding 20ppm does not express the synergistic effect of excess amount and the cost rises.

In the coating composition of the present invention, the conductive polymer is used to exhibit an antistatic effect, and is selected from the group consisting of polyaniline, polypyrrole, polythiophene, poly (3,4-ethylenethiophene) and copolymers thereof. Can be used. Specifically, for example, Baytron P, which is a polythiophene-based conductive polymer of Bayer, may be used. The content of the conductive polymer is used in a range in which the value calculated by Equation 1 satisfies 10 ≦ x ≦ 15 in consideration of the content of the silicone binder resin.

The present invention is an additive to exhibit an antistatic effect, by using the conductive polymer, it is also possible to apply a surfactant-based antistatic agent, in the case of using a surfactant-based antistatic agent, the antistatic agent after coating the surface of the coating layer Migration occurs to increase the release force with the adhesive layer, and the surface resistance depends on the relative humidity in the atmosphere, and in the winter when the humidity is low, the antistatic performance decreases. A large amount of antistatic agent is required, resulting in a higher release force.

Therefore, as a result of the study to solve this, it is possible to solve this by using a conductive polymer has completed the present invention. In this case, by using the content of the conductive polymer in a specific range, it is possible to provide a release film having excellent adhesion and excellent release property and antistatic property.

In the coating composition, water serves as a solvent to uniformly disperse the composition, and may further add additives such as an emulsifier to further improve dispersibility.

The emulsifier may be polyethylene glycol, polyvinyl alcohol, alkyl salt, etc., polyethylene glycol is more preferred. It is preferable to add the emulsifier within the range of 0.5 to 10% by weight because of excellent compatibility.

The method of coating the polyester base film using the coating composition is not particularly limited, but it is preferable to proceed with inline coating, and the release film of the present invention may be prepared by the following process. In the present invention, the in-line coating means a process applied before biaxial stretching after uniaxial stretching in the film manufacturing process.

a) uniaxially stretching in the machine direction to produce a polyester base film having a thickness of 50 to 1500 µm;

b) forming a coating layer by coating the emulsion composition on one or both sides of the prepared base film with a gravure or bar coating method in a range of 1 to 100 μm (wet coating thickness); And

c) drying the film on which the coating layer is formed for 5 to 30 seconds at 200 to 230 ° C. and stretching the film 2 to 6 times in the width direction;

To prepare a release film, including.

After the stretching, the coating layer may have a thickness of 20 to 200 nm.

Release film according to the present invention is a release film having an antistatic performance, has an excellent release property for the protection and removal of the adhesive coating layer, and prevents the generation of static electricity due to the low dielectric constant of the silicon constituting the release layer, It is a release film without foreign matter contamination such as dust when applied.

Hereinafter, the present invention will be described in more detail by way of example, but the present invention is not limited to the following examples.

Physical properties were measured as follows.

1) Antistatic property (surface resistance)

It is measured by a high resistivity measuring instrument (Hiresta-Up, MCP-HT-450) manufactured by Mitsubishi Chemicals, manufactured according to JIS-K6911. During the measurement, the environment should be left for 12 hours at 25 ° C, 20%, 50%, and 60% relative humidity, and then measured for 10 seconds.

2) Release force (peel force)

A release force evaluation sample was prepared based on the FINAT 10 Method, and Nitto31B Tape from Nitto was used as a reference adhesive tape for measurement, and the release force was measured at 180 degrees using a Peel Tester (Chem Instruments, AR-1000). It was measured by the method, the peeling rate is carried out at 300mpm.

Example 1

The value calculated by Equation 1 was adjusted to 10.

That is, 5.28 wt% of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of the following Formula 1 and a polyhydrosiloxane of the Formula 2 at a molar ratio of 1: 1.3, platinum chelate catalyst 1.5 ppm, and a polythiophene conductive polymer. A coating composition was prepared such that the antistatic agent (Bayer, Baytron P) 0.72% by weight and the remaining water to 100% by weight.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

[Equation 1]

x = weight of conductive polymer / (weight of conductive polymer + weight of silicone binder resin) × 100

[Formula 1]

(Wherein x is 25)

[Formula 2]

(Wherein a is 3 and b is 17)

[Example 2]

The value calculated by Equation 1 was adjusted to be 15.

That is, 5.1 wt% of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of Formula 1 and a polyhydrosiloxane of Formula 2 at a molar ratio of 1: 1.3, 1.5 ppm of platinum chelate catalyst, and a polythiophene conductive polymer An inhibitor (Bayer, Baytron P) 0.9% by weight and the water content was adjusted to 100% by weight.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

[Example 3]

The value calculated by Equation 1 was adjusted to be 8.

That is, 5.52% by weight of a silicone binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of the following structural formula 1 and a polyhydrosiloxane of the following structural formula 1: 1.3, a platinum chelate catalyst of 1.5 ppm, and a polythiophene conductive polymer A coating composition was prepared to be 100% by weight using 0.48% by weight of an inhibitor (Bayer, Baytron P) and the remaining water.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

Example 4

In order to adjust the value calculated by Equation 1 to be 20, 4.8% by weight of a silicone-based binder resin having a viscosity of 1000 cps and platinum chelate mixed at a molar ratio of 1: 1.3 of polydimethylsiloxane of the formula 1 and polyhydrosiloxane of the formula 2 1.5 ppm of catalyst, 1.2 wt% of an antistatic agent (Bayer, Baytron P) composed of a polythiophene-based conductive polymer and water content were adjusted to 100 wt%.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

Comparative Example 1

5.76% by weight of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of Formula 1 and a polyhydrosiloxane of Formula 2 at a molar ratio of 1: 1.3, platinum chelate catalyst of 1.5 ppm, and as an antistatic agent [Formula 3] and [ The anionic surfactant of Structural Formula 4] was mixed at 50:50 to adjust the content of 0.24 wt% and water to 100 wt%.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

[Formula 3]

(Wherein R is lauryl)

[Structure 4]

(Wherein R is lauryl)

Comparative Example 2

5.52 wt% of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of Formula 1 and a polyhydrosiloxane of Formula 2 at a molar ratio of 1: 1.3, platinum chelate catalyst of 1.5 ppm, and an antistatic agent as described in [Formula 3] and [ 0.48% by weight of the mixture of the anionic surfactant of Structural Formula 4] at 50:50 and the water content were adjusted to 100% by weight.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

Comparative Example 3

5.76% by weight of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of Formula 1 and a polyhydrosiloxane of Formula 2 at a molar ratio of 1: 1.3, cation of 1.5 ppm in platinum chelate catalyst, and an antistatic agent. 0.24 wt% of the surfactant and the amount of water were adjusted to 100 wt%.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

[Structure 5]

[Comparative Example 4]

5.76% by weight of a silicone-based binder resin having a viscosity of 1000 cps mixed with a polydimethylsiloxane of Formula 1 and polyhydrosiloxane of Formula 2 at a molar ratio of 1: 1.3, cation of 1.5 ppm, a platinum chelate catalyst, and an antistatic agent. 0.48 wt% of the surfactant and the amount of water were adjusted to 100 wt%.

By uniaxially stretching in the machine direction to produce a polyethylene terephthalate (PET) film having a thickness of 100㎛, the surface of the prepared PET substrate film in the following structural in-line process using the Mayer Bar (Mayer Bar) It was applied at 10 μm (wet). After drying at 220 ° C. for 20 seconds, the film was stretched four times in the width direction to have a thickness of 125 nm of the final coated coating layer.

[Table 1]

As shown in Table 1, the release film according to the present invention was found to satisfy both antistatic properties and release properties at the same time. In particular, it can be seen that Example 1 and Example 2 can achieve more excellent antistatic properties and releasability in the range of the content ratio (x) according to the formula (1) is 10 ≤ x ≤ 15.

As shown in Comparative Examples 1 to 4, when the surfactant-based antistatic agent was used instead of the conductive polymer of the present invention, the antistatic property was included in the intended range, but it was found that the release force was greatly increased so that it could not be used as a release film. .

Claims (6)

A release film comprising a coating layer coated with a coating composition containing a silicone-based binder resin and a conductive polymer on one surface of a polyester base film layer. The method of claim 1,
The content ratio of the silicone-based binder resin and the conductive polymer is a release film having a value (x) according to Equation 1 below 10 ≦ x ≦ 15.
[Equation 1]
x = weight of conductive polymer / (weight of conductive polymer + weight of silicone binder resin) × 100 The method of claim 1,
The coating composition includes a silicone-based binder resin, a conductive polymer, a platinum chelate catalyst and water, and has a solid content of 1 to 25 wt%. The method of claim 1,
The silicone binder resin is a release film that is used by mixing the polydimethyl siloxane of the following structural formula 1 and the polyhydrosiloxane of the structural formula 2 1: 1: 0.5 ~ 2 molar ratio.
[Formula 1]

(Wherein x is an integer from 1 to 50).
[Formula 2]

(Wherein a is an integer of 1 to 50 and b is an integer of 1 to 50). The method of claim 1,
And the conductive polymer is selected from the group consisting of polyaniline, polypyrrole, polythiophene, poly (3,4-ethylenethiophene) and copolymers thereof. The method according to any one of claims 1 to 5,
The release film is a release film having an antistatic performance of 1 × 10 ¹¹ ohm / sq or less by surface resistivity measured according to JIS-K6911, and a release force of 30 gf / inch or less measured according to FINAT 10 Method.