KR102392098B1 - Release film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a release film and a method for manufacturing the same. In more detail, it relates to an in-line coating carbide release film used in the field of electronic materials such as ceramic multilayer capacitors (MLCC), polarizing plate protection, and OCA (Optically Clear Adhesive).

Description

Release film and manufacturing method thereof

The present invention relates to a release film and a method for manufacturing the same. In more detail, it relates to an in-line coating carbide release film used in the field of electronic materials such as ceramic multilayer capacitors (MLCC), polarizing plate protection, and OCA (Optically Clear Adhesive).

The release film is used for an adhesive surface protection film for using an adhesive or an adhesive, or a carrier sheet for supporting a flexible material.

On the other hand, the shape of the pressure-sensitive adhesive or adhesive is changing from a liquid to a sheet in order to diversify the uses and varieties of optical products and to improve productivity.

The release film that protects the sheet shape temporarily protects the adhesive surface of the adhesive product from contamination by dust, debris, moisture or other contaminants until the label is used, and then is separated from the adhesive surface immediately before use of the adhesive product. Therefore, the release film is formed with a coating layer capable of imparting peelability to the surface of the product and at the same time providing adhesion to the product.

The release film can be prepared in a solvent type or an emulsion type depending on the coating method or use. In general, the emulsion-type composition has a problem that has poor stability and requires high temperature curing due to high latent heat of evaporation due to the use of water as a dispersion medium.

The release film applied to off-line coating has a low drying process temperature and a short drying line, so a solvent-type or solvent-free coating composition is mainly used.

Since the release film applied to in-line coating has a risk of explosion due to the use of solvents in the PET film film forming process, an emulsion-type composition is mainly used.

The reason why such an emulsion-type composition is applied to the in-line coating is that sufficient crosslinking is possible because the temperature of the tenter process is high. However, the silicone emulsion composition for in-line coating has a problem in that the raw materials used are limited due to the need to be stretchable, so the in-line coating silicone release film is extremely limitedly produced.

In order to solve the above problems, various attempts have been made to provide a composition for in-line coating that is easy to peel at the initial stage, has a sufficient curing reaction, has a high residual adhesive rate, and has a low back transfer rate, and a release film using the same.

Korean Patent Application Laid-Open No. 2014-0080659 discloses a technique for controlling a peel force ratio by including an organo polysiloxane resin including a hydroxyl group or an alkenyl group as a peel force control agent. However, in the above technique, light peeling, that is, the release force can reach only about 20 gf/inch, and it is difficult to implement ultra-hard peeling, that is, the release force is 10 gf/inch or less. In addition, the in-line coating method has a limitation in increasing the coating thickness, and as the thickness of the coating layer increases, the winding property after manufacturing decreases, the coating appearance is poor, or the unit cost of the coating raw material is increased. R&D is required.

The present invention has been derived to solve the above problems, and the initial release force can achieve super light peelability of 10 gf/inch or less, the change in the release force over time is small, and the release film has an excellent coating appearance and its An object of the present invention is to provide a manufacturing method.

In addition, an object of the present invention is to provide a release film having excellent winding characteristics and residual adhesiveness, and minimizing deviation in release force, and a method for manufacturing the same.

The present invention relates to a release film and a method for manufacturing the same.

The present invention provides a release film comprising a polyester base film and a release coating layer formed on one or both surfaces of the base film. In this case, the release coating layer includes silicon beads having an average particle diameter of 0.05 μm to 2 μm, and satisfying Equations 1 to 3 below.

[Equation 1]

R _i ≤ 10

[Equation 2]

|R _f - R _i | ≤ 20

[Equation 3]

|R _f-max - R _f-min | ≤ 1.2

In Equations 1 to 3, R _i is the release force measured after standing at 55° C. for 24 hours, R _f is the release force measured after leaving it at 55° C. for 240 hours, and R _{f -max} is 55° C. It is the maximum value among the release forces measured 5 times after leaving it at for 240 hours, and R _f-min is the minimum value among the release forces measured 5 times after leaving it for 240 hours at 55°C.

In the release film according to an embodiment of the present invention, the release coating layer may be formed of a release coating layer composition comprising a silicon compound composition and silicone beads dispersed in alcohol. At this time, the silicone beads may be mixed with the release coating layer composition in a dispersed state using any one or more alcohols selected from anhydrous ethanol and anhydrous isopropyl alcohol as a dispersion medium.

In the release film according to an embodiment of the present invention, the silicon compound composition may include a silicon compound, a platinum-based catalyst, and a silicone-based wetting agent.

The silicon compound may include any one or two or more compounds selected from the following Chemical Formulas 1 to 3 and a compound represented by Chemical Formula 4.

[Formula 1]

In Formula 1, n is 20 to 3000, m is 1 to 500, and n+m is 21 to 3000.

[Formula 2]

In Formula 2, x is 1 to 3000.

[Formula 3]

In Formula 3, R ₁ , R ₂ , R ₃ and R ₄ are each independently -CH=CH ₂ , -(SiC ₂ H ₆ O) _k CH=CH ₂ , -(SiC ₂ H ₆ O) _k ( CH ₂ ) _l CH=CH ₂ Any one selected from, k and l are each independently 0 to 300, y is 20 to 3000, z is 1 to 500, and y + z is 21 to 3000.

[Formula 4]

In Formula 4, a is 1-150, b is 3-300, and a+b is 5-300.

Also, the present invention

a) melt-extruding a polyester resin to prepare a sheet;

b) stretching the sheet in the longitudinal direction;

c) applying a release coating layer composition comprising a silicon compound composition and silicone beads to one or both surfaces of the sheet in step b) by an in-line coating method;

d) preparing a release film by drying and preheating the sheet in step c) and then stretching in the transverse direction; and

e) heat-treating the release film;

It provides a release film manufacturing method comprising a.

In the method for manufacturing a release film according to an embodiment of the present invention, the release coating layer composition may include separately mixing silicone beads dispersed in alcohol.

In the method for manufacturing a release film according to an embodiment of the present invention, the silicone beads may have an average particle diameter of 0.05 μm to 2 μm.

In the method of manufacturing a release film according to an embodiment of the present invention, the silicon compound composition may include a silicon compound, a platinum-based catalyst, and a silicone-based wetting agent.

In the manufacturing method of the release film according to an embodiment of the present invention, step d) may be performed drying and preheating at 140 ℃ or less.

In the method of manufacturing a release film according to an embodiment of the present invention, the stretching of step b) or step d) may be performed at 80 to 150°C.

The release film according to the present invention can achieve carbide peelability of 10 gf/inch or less even when the in-line coating method is applied. In addition, there is an advantage in that there is little change in release force over time, excellent coating appearance, excellent peel stability by minimizing variation in release force, and improvement of defects due to adhesive lifting that may occur during release film peeling. .

Through the realization of the above physical properties, the release film according to the present invention can be applied to various fields such as capacitors, photo films, labels, pressure-sensitive tapes, decorative laminates, transfer tapes, polarizing plates, and green sheets for ceramic release. there is.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the following specific examples or examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto and may be implemented in various forms.

Further, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention.

Further, the singular forms used in the specification and appended claims may also be intended to include the plural forms unless the context specifically dictates otherwise.

The release film according to the present invention comprises a polyester base film and a release coating layer formed on one or both sides thereof, wherein the release coating layer includes silicone beads having an average particle diameter of 0.05 μm to 2 μm, and Formulas 1 to 3 is satisfied.

[Equation 1]

R _i ≤ 10

[Equation 2]

|R _f - R _i | ≤ 20

[Equation 3]

|R _{f -max} - R _{f -min} | ≤ 1.2

In Equations 1 to 3, R _i is the release force measured after standing at 55° C. for 24 hours, R _f is the release force measured after leaving it at 55° C. for 240 hours, and R _{f -max} is 55° C. It is the maximum value among the release forces measured 5 times after leaving it at for 240 hours, and R _{f -min} is the minimum value among the release forces measured 5 times after leaving it for 240 hours at 55°C.

In the present invention, the polyester base film may be made of a polyester resin obtained by polycondensation of an acid component containing dicarboxylic acid as a main component and a glycol component containing alkyl glycol as a main component.

As the main component of the dicarboxylic acid, terephthalic acid or its alkyl ester, phenyl ester, etc. are mainly used, but a part thereof is, for example, isophthalic acid, oxyethoxybenzoic acid, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, etc. It can be used instead of difunctional carboxylic acid or its ester-forming derivative.

As the glycol component, ethylene glycol is mainly used, but a part thereof is, for example, propylene glycol, trimethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 1,4-bisoxyethoxybenzene. , bisphenol, and polyoxyethylene glycol may be used instead of, and if the content is small, a monofunctional compound or a trifunctional compound may be used in combination.

In the present invention, when the release coating layer satisfies the following formulas 1 to 3, there is little change in the release force over time, and uniform adhesive properties can be achieved.

[Equation 1]

R _i ≤ 10

[Equation 2]

|R _f - R _i | ≤ 20

[Equation 3]

|R _{f -max} - R _{f -min} | ≤ 1.2

In Equations 1 to 3, R _i is the release force measured after leaving at 55° C. for 24 hours, R _f is the release force measured after leaving it at 55° C. for 240 hours, and R _{f -max} is at 55° C. It is the maximum value among the release forces measured 5 times after standing for 240 hours, and R _{f -min} is the minimum value among the release forces measured 5 times after leaving it for 240 hours at 55°C.

Equation 1 represents the carbide peelability of the release film, and when it is out of the above range, it is difficult to achieve the carbide peelability required in the present invention. The lower limit of Formula 1 is not particularly limited, but preferably, the release force R _i is 3 or more. When the release force R _i is less than 3, the initial release force is too low, so that the adhesion to the adherend may not be properly expressed.

Equation 2 means the change with time of the release force. The smaller the change over time, the better because it can be stored and used for a long time after being made into a final product. Although the lower limit of Equation 2 is not particularly limited, it is preferable that the change over time (|R _f - R _i |) of the release force is 10 or more. If the change over time of the release force is less than 10, it is better because no trace of peeling is left when peeling the film with a machine with a width of 1,000 mm or more. On the other hand, when the change in release force over time is more than 20, high release force appears when peeling a film width of 1,000 mm or more, so traces of peeling of the release film may remain on the surface of the green sheet or sheet for electronic materials.

Equation 3 means the release force deviation, and when the deviation of the values of the measured release force after standing at 55 ° C. for 240 hours is less than 1.2, the release force deviation cannot be felt, and the noise generated during peeling does not appear. Do. On the other hand, when it exceeds 1.2, a deviation in the release force can be sensed, and a noise during peeling, that is, a clicking sound that appears when peeling occurs, as well as not uniformly peeling as a whole may cause defects.

In order to realize the balance of the physical properties, the release coating layer according to the present invention is formed of a release coating composition comprising a silicon compound composition and silicone beads dispersed in alcohol. The release coating composition is not particularly limited, but may consist of 10 to 40% by weight of the silicon compound composition, 0.1 to 5% by weight of silicone beads, 5 to 20% by weight of alcohol, and the remaining amount of the solvent. At this time, the silicone beads are preferably mixed with the release coating composition in the form of dispersion using anhydrous ethanol or anhydrous isopropyl alcohol as a dispersion medium.

The silicon compound composition may include a silicon compound, a platinum-based catalyst, and a silicon-based wetting agent.

The silicon compound may include any one or two or more compounds selected from the following Chemical Formulas 1 to 3 and a compound represented by Chemical Formula 4.

[Formula 1]

In Formula 1, n is 20 to 3000, m is 1 to 500, and n+m is 21 to 3000.

[Formula 2]

In Formula 2, x is 1 to 3000.

[Formula 3]

In Formula 3, R ₁ , R ₂ , R ₃ and R ₄ are each independently -CH=CH ₂ , -(SiC ₂ H ₆ O) _k CH=CH ₂ , -(SiC ₂ H ₆ O) _k ( CH ₂ ) _l CH=CH ₂ Any one selected from, k and l are each independently 0 to 300, y is 20 to 3000, z is 1 to 500, and y + z is 21 to 3000.

[Formula 4]

In Formula 4, a is 1-150, b is 3-300, and a+b is 5-300.

Each of the compounds represented by Chemical Formulas 1, 2 and 3 is a prepolymer state of a siloxane structure as a subject of the release coating layer. In addition, the compound represented by Chemical Formula 4 is a curing agent, and reacts with Chemical Formulas 1 to 3 to form polydimethylsilicone resin (PDMS). The vinyl group of Formulas 1 to 3 and the silane group of Formula 4 react, and in Formula 3, Silane Group (Si-H) and Si-CH ₃ Randomly cross It has the advantage of having a lower steric hindrance and a faster reaction rate than a curing agent in which only Si-H is continuous, and it is preferable because it does not impair the physical properties of the polyester base film of the present invention.

Commercialized examples of the compound represented by Formula 1 include, but are not limited to, Dehesive 490 manufactured by Wacker Chemie AG. Commercialized examples of the compound represented by Formula 2 include, but are not limited to, Dehesive 430 manufactured by Wacker Chemie AG, KM3951 manufactured by shin-etsu, and KM3952 manufactured by shin-etsu. In addition, commercialized examples of the compound represented by Chemical Formula 3 include Dehesive 440 by Wacker Chemie AG, SYL-OFF 7920 by Dowcorning, SYL-OFF 7924 by Dowcorning, and the like, but are not limited thereto. Commercialized examples of the compound represented by Formula 4 include, but are not limited to, Crosslinker V72 and Crosslinker V15 manufactured by Wacker Chemie AG.

In the present invention, the platinum-based catalyst promotes a reaction between the vinyl group of polydimethylsiloxane of the compound represented by Formulas 1 to 3 and hydrogen of the polyhydrosiloxane of the compound represented by Formula 4, whereby the coating layer adheres to the base film. It plays a role in increasing the strength, that is, adhesion. The platinum catalyst is preferably included in an amount of 1 to 20 ppm in the total silicon compound composition. When the above range is satisfied, the effect of improving the reactivity is increased, and the manufacturing cost can be reduced. Commercialized examples of the platinum-based catalyst include, but are not limited to, EM440 manufactured by Wacker Chemie AG. In addition, commercial examples of the silicone-based wetting agent include, but are not limited to, Q2-5211 manufactured by Dow Corning.

In the release coating composition according to the present invention, the solid content of the compound of Formulas 1, 2 or 3 may be 5 to 25% by weight, preferably 8 to 16% by weight. When the above range is satisfied, the surface of the polyester film can be sufficiently coated, and the residual adhesive rate can be effectively controlled by increasing the reaction conversion rate.

In addition, the solid content of the compound of Formula 4 may be 0.5 to 5% by weight, preferably 0.8 to 2% by weight. When the above range is satisfied, the release coating layer can be sufficiently cured, and the change in the release force over time can be reduced without unreacted silane groups.

In addition, the solid content of the platinum-based catalyst may be 0.001 to 3% by weight, preferably 0.005 to 0.1% by weight. In the above range, the effect of adding the catalyst is sufficiently expressed, and the non-uniformity of the release force can be suppressed.

In addition, the solid content of the silicone-based wetting agent is more preferably 0.1 to 3% by weight, preferably 0.5 to 2% by weight. When the above range is satisfied, it is possible to prevent coating stains while lowering the haze of the film to be manufactured.

In a preferred embodiment, the silicon compound composition includes the compound of Formula 1, the compound of Formula 4, a platinum-based catalyst and a silicone-based wetting agent, or the compound of Formula 2, the compound of Formula 4, a platinum-based catalyst, and a silicone-based compound A wetting agent may be included, or the compound of Formula 3, the compound of Formula 4, a platinum-based catalyst, and a silicone-based wetting agent may be included. More preferably, the silicon compound may include a combination of the compounds represented by Chemical Formulas 2 and 4 to reduce the deviation in the release force and improve the residual adhesive force.

In the present invention, the silicon compound composition may include 10 to 40% by weight of 100% by weight of the total release coating layer composition. In the above range, it is possible to suppress waste of unreacted silicon compounds while improving adhesion between the base film and the coating layer.

In the present invention, the silicone bead has a low peeling force and uniform surface roughness, and can lower the release force by lowering the contact area with the adhesive. In this case, the silicon beads may have an average particle diameter of 0.05 μm to 2 μm. If it is less than 0.05㎛, the effect is insignificant, and if it is more than 2㎛, the stability of the crude solution may be deteriorated due to the precipitation of silicon beads, and the appearance of the coating may be poor.

In addition, the silicon beads have a coefficient of variation (Coefficient of Variance, C.V. = Standard Size of silicon beads/Average Size of silicon beads used) of 20 or less, and a moisture analyzer at 120 ° C., 30 min. The measured moisture content may be 0.6% or less. When the coefficient of variation of the silicon bead is greater than 20, as the size distribution difference according to the production lot of the silicon bead is large, the difference in coating properties and runability may increase, and thus the reproducibility of the product may be deteriorated. In addition, when the moisture content is more than 0.6%, it may become an inhibitory factor of the silicone reaction according to moisture.

In the present invention, the silicone beads may include 0.1 to 5% by weight of 100% by weight of the total release coating layer composition. If it is less than 0.1% by weight, it cannot play a role of lowering the release force because it does not form roughness, and if it exceeds 5% by weight, the reaction conversion rate of the release reaction may be lowered, and the coating appearance may be poor.

In the present invention, the silicone beads are dispersed in alcohol to exhibit more uniform dispersibility, and a desired synergistic effect can be realized in combination with other components. In this case, the alcohol is preferably anhydrous alcohol, and more preferably, may be any one selected from anhydrous ethanol and anhydrous isopropyl alcohol or a mixture thereof. This is because, when water is used as a dispersing solvent, dispersibility is further deteriorated because the silicon bead itself has a small particle size and at the same time the surface of the silicon is hydrophobic. At the same time, the alcohol according to the present invention is characterized in that anhydrous alcohol is used, unlike conventional water containing about 20 to 30%. When such anhydrous alcohol is used, the dispersion of the silicone beads is further improved, and it is possible to prevent appearance defects from occurring.

The release film according to the present invention may have a residual adhesive ratio of 90% or more.

In the range where the residual adhesion rate is 90% or more, it can be determined that the unreacted material of the release film is low, so it is preferable because the amount of the unreacted material of the release film transferred to the final product after post-processing at the customer is small.

In the release film according to the present invention, the thickness of the polyester base film may be 10 to 200 µm, more preferably 10 to 50 µm, and the thickness of the release coating layer is 0.01 to 0.5 µm, more preferably 0.1 to 0.3 µm may be, but the present invention is not limited thereto.

The method of manufacturing a release film according to the present invention has the advantage of maximizing product properties by controlling the surface properties of the base film, and reducing costs by introducing an inline coating process, thereby maximizing economical and productivity.

The manufacturing method of the release film according to the present invention is

a) melt-extruding a polyester resin to prepare a sheet;

b) stretching the sheet in the longitudinal direction;

c) applying a release coating layer composition comprising a silicon compound composition and silicone beads to one or both surfaces of the sheet in step b) by an in-line coating method;

d) preparing a release film by drying and preheating the sheet in step c) and then stretching in the transverse direction; and

e) heat-treating the release film;

includes

At this time, the release coating layer composition is characterized in that the silicone beads dispersed in alcohol are mixed separately.

In step c), the release coating composition may be applied using a gravure roll. When a gravure coating roll is used, the release coating composition may be applied to a uniform thickness.

In step d), drying and preheating are preferably performed at 140° C. or less, more specifically, at 110 to 140° C. In the case of exceeding 140 ° C., the deviation of the release force may increase and thus the uniformity may be greatly reduced.

In addition, the step b) or step d) is preferably carried out at 80 to 150 ℃ stretching. If the temperature is less than 80°C, the heat required for stretching is not sufficient, so stretching does not occur properly, and if it is more than 150°C, thermal wrinkles or orange peel may occur on the film.

In addition, the stretching ratio during stretching in step d) is not particularly limited, but may be stretched 3 to 5 times in the machine direction (MD) and the width direction (TD), respectively. While maintaining the thickness uniformity of the film produced in the above range, it is possible to suppress the breakage of the film.

The heat treatment in step e) may be performed at 230 to 250 °C. If the temperature is lower than 230°C, the release coating layer may not react sufficiently, so that the release coating layer may be pushed. If it is higher than 250°C, thermal wrinkles and orange peel of the film may occur.

Hereinafter, for a more detailed description of the present invention, examples are given for description, but the present invention is not limited to the following examples.

The following physical properties were measured as follows.

1) Measurement of coating uniformity

In the polyester release film, if the area of the portion where the release layer is not formed compared to the area of the base film is 1% or less, it is indicated as good, and if it exceeds 1%, it is indicated as defective.

2) Coating thickness

After measuring the silicon content of the release layer with a calibrated XRF device (LX3500, Oxford), it was converted into a coating thickness and expressed.

3) release force

The release force was measured using TESA 7475 as a standard tape according to the method of FINAT 10.

(1) Release force R _i

TESA 7475 was placed on the release coating layer of the films prepared in Examples and Comparative Examples and reciprocated twice using a 2Kg rubber roll, and then 5 samples were prepared by cutting 50mm×15cm samples at 10cm intervals. After applying a load of 70 g/cm 2 to the prepared sample and leaving it at 55° C. for 24 hours, Peel Tester (Chem Instrument, AR-1000) was used to evaluate peel peeling at 180 degrees. The peeling rate was 300 mm/min. The release force of the five samples was measured and the average value was shown.

(2) Release force R _f

TESA 7475 was placed on the release coating layer of the films prepared in Examples and Comparative Examples and reciprocated twice using a 2Kg rubber roll, and then 5 samples were prepared by cutting 50mm×15cm samples at 10cm intervals. After applying a load of 70 g/cm 2 to the prepared sample and leaving it at 55° C. for 240 hours, Peel Tester (Chem Instrument, AR-1000) was used to evaluate peel peeling at 180 degrees. The peeling rate was 300 mm/min. The release force of the five samples was measured and the average value was shown.

(3) Change with time of release force (|R _f - R _i |)

Let the difference value between the releasing force R _f and the releasing force R _i be the change with time of the releasing force.

(4) Deviation of release force (|R _f-max R _f-min |)

The release force R _f At the time of measurement, the maximum value of the release force measured 5 times was R _{f -max} , and the minimum value was R _f-min , and the difference value was calculated.

4) Residual adhesion rate

(1) First adhesive strength: Nitto 31B Tape, a standard tape, was left at 70° C. for 24 hours, then laminated on a Teflon sheet, and compressed twice with a 2 kg rubber roll. Adhesion of the Nitto 31B Tape of the laminated sample was measured using a 180 degree peel tester (Chem Instrument's AR1000).

(2) Second adhesive strength: Nitto 31B Tape, a standard tape, was adhered to the release coating layer of the films prepared in Examples and Comparative Examples, and left at 70° C. for 24 hours under a load of 70 g/cm 2 The Nitto 31B Tape was removed. The removed Nitto 31B Tape was again laminated on a Teflon sheet, and compressed twice with a 2 kg rubber roll. Adhesion of the Nitto 31B Tape of the laminated sample was measured using a 180 degree peel tester (Chem Instrument's AR1000).

Residual adhesive force was measured as in Equation 4 below. The unit is gf/inch, and it is satisfied when the residual adhesion rate is 90% or more.

[Equation 4]

Residual adhesion rate = (second adhesion / first adhesion) × 100

The compositions used in the following Examples and Comparative Examples are as follows.

Coating solution 1: As a silicon compound of Formula 1, polydimethylsiloxane (Wacker Chemie AG, DEHESIVE® 490) as a solid content of 49.99 wt%, a platinum catalyst (Wacker Chemie AG, EM440) as a solid content of 0.01 wt%, A composition having a total solids content of 50% by weight.

Coating solution 2: The silicon compound of Formula 2 contains 49.99 wt% of polydimethylsiloxane (Shin-Etsu, KM3951) as a solid content, and 0.01 wt% of a platinum catalyst (Wacker Chemie AG, EM440) as a solid content, and the total solid content is 50% by weight of the composition.

Coating solution 3: As a silicon compound of Formula 4, a hydrogen silane compound (Wacker Chemie AG, Crosslinker V15, a compound in which a is 5, b is 95, and a weight average molecular weight of 4000 g/mol in Formula 4) as a solid content A composition comprising 50% by weight.

The weight average molecular weight is measured by gel chromatography (GPC) using styrene as a standard material.

Coating solution 4: A silicone-based wetting agent, Dow Corning, Q2-5212, a composition having a solid content of 80% by weight.

Coating solution 5: 49.99% by weight of Dow Corning, SYL-OFF ^® 7920 containing polydimethylsiloxane of Formula 3 and hydrogensilane-based compound of Formula 4, solids content of platinum catalyst (Wacker Chemie AG, EM440) As a composition comprising 0.01% by weight, the total solid content is 45% by weight.

[Example 1]

20 wt% of the coating solution 1, 1 wt% of the coating solution 3, 0.5 wt% of the coating solution 4, 0.5 wt% of silicone beads, and the remaining amount of water were used as solvents to prepare a crude solution. In addition, the silicone beads were separately dispersed using absolute ethanol and mixed to prepare a liquid. At this time, the content of absolute ethanol is 10% by weight of the total coating solution composition.

Next, 1000 g of dimethyl terephthalet, 576 g of ethylene glycol, 300 ppm of magnesium acetate and 400 ppm of trimethyl phosphate relative to the polyester resin content were put into the reactor, and the transesterification reaction was performed while flowing out methanol. Thereafter, a polycondensation reaction was performed at 285° C. under a vacuum of 0.3 torr to obtain a polyester chip having an intrinsic viscosity of 0.61.

The polyester chips were melt-extruded at 280°C and then rapidly cooled to 24°C using a large roll to obtain a polyester sheet. The obtained polyester sheet was stretched 3.5 times in the longitudinal direction at 110° C., and a coating solution was applied to the cooled film using a gravure coater.

Then, after drying and preheating at 125° C., the film was stretched 3.5 times in the transverse direction to prepare a biaxially oriented film. The obtained biaxially oriented film was heat-treated at 240° C. to obtain a release film having a thickness of 25 μm. The physical properties of the obtained release film were measured and shown in Table 2 below.

[Examples 2 to 9 and Comparative Examples 1 to 3]

As shown in Table 1 below, a release film was prepared in the same manner as in Example 1, except that the composition ratio of the coating solution and the preheating temperature were changed. The physical properties of the prepared release film were measured and shown in Table 2 below.

Release coating layer composition Preheating temperature (℃) after coating solution is applied coating solution silicone beads One 2 3 4 5 dispersion solvent
Kinds average particle diameter
(μm) addition amount
(weight%) Example 1 20 - One 0.5 - ET 0.5 0.5 125 Example 2 20 - One 0.5 - IPA 0.3 One 125 Example 3 20 - One 0.3 - IPA 0.1 3 120 Example 4 - 20 One 0.5 - ET 0.5 0.5 125 Example 5 - 20 One 0.5 - IPA 0.3 One 125 Example 6 - 20 One 0.3 - IPA 0.1 3 120 Example 7 - 20 One One - IPA One 0.05 130 Example 8 20 - One One - IPA 2 0.05 130 Example 9 0 0 0 0.5 20 IPA 0.5 0.05 125 Comparative Example 1 20 - 1.5 One - - - 0.5 130 Comparative Example 2 20 - One 0.5 - water 0.5 0.5 130 Comparative Example 3 20 - One 0.5 - ET 0.5 0.5 150

In Table 1, ET is anhydrous ethanol, and IPA is anhydrous isopropyl alcohol.

coating
uniformity coating thickness
(μm) R _i
(gf/inch) release force after aging Residual adhesion rate
(%) R _f
(gf/inch) Change of release force over time Deviation of release force Example 1 Good 0.2 4 19 15 One 93 Example 2 Good 0.2 4 18 14 0.9 92 Example 3 Good 0.2 5 21 16 0.9 92 Example 4 Good 0.2 4 17 13 0.5 92 Example 5 Good 0.2 4 15 11 0.9 92 Example 6 Good 0.25 5 19 14 0.3 94 Example 7 Good 0.2 4 18 14 0.4 92 Example 8 Good 0.2 4 18 14 0.6 91 Example 9 Good 0.2 5 19 14 0.5 93 Comparative Example 1 error 0.2 8 35 27 One 95 Comparative Example 2 error Unable to measure due to poor appearance Comparative Example 3 error 0.2 7 22 15 1.5 92

As can be seen in Table 2, the release film prepared through the present invention has good coating uniformity, and it can be seen that the release force R _i is as low as 10 or less. In addition, according to Equation 2, the change over time of the release force was 20 or less, and the deviation of the release force according to Equation 3 was 1.2 or less, all of which were satisfied. In addition, it was confirmed that the amount of unreacted material was low as the residual adhesion rate was 90% or more.

On the other hand, in the case of the comparative example, it can be seen that the initial release force is high and the deviation of the release force is large. In particular, in the case of Comparative Example 2 using water as the dispersion solvent, it was confirmed that the physical properties could not be measured due to poor appearance, and in Comparative Example 3, as the preheating temperature was 150° C. there is.

As described above in detail a specific part of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (11)

A polyester base film and a release coating layer formed on one or both sides thereof,
The release coating layer contains silicon beads having an average particle diameter of 0.05 to 2 μm,
The release coating layer is formed of a release coating layer composition comprising a silicon compound composition and silicone beads dispersed in alcohol,
The alcohol is anhydrous alcohol,
A release film, characterized in that it satisfies the following formulas 1 to 3.
[Equation 1]
R _i ≤ 10 gf/inch
[Equation 2]
|R _f - R _i | ≤ 20 gf/inch
[Equation 3]
|R _f-max - R _f-min | ≤ 1.2 gf/inch
In Equations 1 to 3, R _i is the release force measured after standing at 55 ° C. for 24 hours, R _f is the release force measured after leaving it at 55 ° C. for 240 hours, and R _f-max is 55 ° C. It is the maximum value among the release forces measured 5 times after leaving it at for 240 hours, and R _f-min is the minimum value among the release forces measured 5 times after leaving it for 240 hours at 55°C. delete delete The method of claim 1,
The silicon compound composition is a release film comprising a silicon compound, a platinum-based catalyst and a silicone-based wetting agent. 5. The method of claim 4,
The silicon compound is a release film comprising any one or two or more compounds selected from the following Chemical Formulas 1 to 3 and a compound represented by Chemical Formula 4.
[Formula 1]

In Formula 1, n is 20 to 3000, m is 1 to 500, and n+m is 21 to 3000.
[Formula 2]

In Formula 2, x is 1 to 3000.
[Formula 3]

In Formula 3, R ₁ , R ₂ , R ₃ and R ₄ are each independently -CH=CH ₂ , -(SiC ₂ H ₆ O) _k CH=CH ₂ , -(SiC ₂ H ₆ O) _k ( CH ₂ ) _l CH=CH ₂ Any one selected from, k and l are each independently 0 to 300, y is 20 to 3000, z is 1 to 500, and y + z is 21 to 3000.
[Formula 4]

In Formula 4, a is 1-150, b is 3-300, and a+b is 5-300. a) melt-extruding a polyester resin to prepare a sheet;
b) stretching the sheet in the longitudinal direction;
c) applying a release coating layer composition comprising a silicon compound composition and silicone beads to one or both surfaces of the sheet in step b) by an in-line coating method;
d) preparing a release film by drying and preheating the sheet in step c) and then stretching in the transverse direction; and
e) heat-treating the release film; including,
The release coating layer composition comprises separately mixing silicone beads dispersed in alcohol,
The alcohol is anhydrous alcohol,
The silicon beads have an average particle diameter of 0.05 to 2 μm,
The method for manufacturing the release film of claim 1. delete delete 7. The method of claim 6,
The silicon compound composition is a method for producing a release film comprising a silicon compound, a platinum-based catalyst and a silicone-based wetting agent. 7. The method of claim 6,
The step d) is a method for producing a release film to carry out drying and preheating at 140 ℃ or less. 7. The method of claim 6,
The step b) or step d) stretching the release film production method is carried out at 80 to 150 ℃.