KR102239262B1 - Release film - Google Patents

Abstract

The release film of the present invention is a base film; A release layer applied to at least one surface of the base film; Including, After applying the pressure-sensitive adhesive on one side of the release film, peeling force (A) at the time of peeling at a peeling rate of 0.1 to 30m/min and the peeled release film are re-laminated with the pressure-sensitive adhesive and peeled at the same speed. It is characterized in that the ratio (B/A) of the peel force (B) at the time is 0.5 to 3.0.
The release film has little change in peeling force even when relaminated after peeling, and little damage to the adhesive layer upon peeling.

Description

Release film {RELEASE FILM}

The present invention relates to a release film, and more particularly, comprises a release layer applied to at least one side of a base film, and by adjusting the composition and thickness of the release layer, the release film is re-laminated after peeling. It relates to a release film having little change in peel force and less damage to the adhesive layer.

Release film is a film that has so-called release properties that do not adhere well to the sticky and adhesive components.

It is generally attached to a sticky adhesive film or tape for a protective film, and is used to prevent the sticky adhesive from being adhered to unwanted adherends or contaminated by dust or foreign matter before use. In addition, it plays a role of preventing the mold and the molded object from sticking in the heating and press molding process, such as printed wiring boards and in-mold molding, or used as a carrier film for forming thin ceramic sheets such as dielectrics for multilayer ceramic capacitors. It is also possible.

After the release film is laminated to protect the adhesive layer, it is removed at the stage where the final adhesive product is used. In the adhesive processing process, the release film may be temporarily removed and then relaminated for the purpose of improving the yield and process capability.In this case, the peeling force and physical properties of the release film should not change even after the relamination, and the adhesive layer is also damaged. There shouldn't be.

The release film usually forms a thin-film release layer in which a silicone component is crosslinked, and its durability is not high due to external temperature, humidity, and friction. When the release layer is exposed to the outside for a long period of time, the peel strength and adhesion tend to change significantly due to the influence of temperature, humidity, and fine foreign matter. If the release film is peeled and relaminated in the adhesion process, the physical properties of the release film release layer are deteriorated after the relamination, resulting in increased peeling force, and in the case of a soft adhesion layer, damage such as irregularities on the surface of the adhesion layer. Was confirmed.

Republic of Korea Patent Registration No. 10-1493832 is a release film in which at least one side of a polyester film is coated with a curable silicone-based paint, which is light when peeling, has excellent retention power during storage, and has excellent atmospheric exposure and non-compliance. The film is disclosed. However, the patent does not describe changes in peeling force and changes in physical properties of the adhesive layer during re-peeling.

KR 10-1493832 B1

An object of the present invention is to provide a release film with little change in peeling force even when the adhesive layer and the adhesive layer are relaminated after peeling.

Another object of the present invention is to provide a release film with less damage to the adhesive layer during peeling.

The release film of the present invention for achieving the above object, a base film; A release layer applied to at least one surface of the base film; Including, After applying the pressure-sensitive adhesive on one side of the release film, peeling force (A) at the time of peeling at a peeling rate of 0.1 to 30 m/min and the peeled release film are re-laminated with the pressure-sensitive adhesive, and then peeled at the same speed. It is characterized in that the ratio (B/A) of the peel force (B) at the time is 0.5 to 3.0.

The low-speed (0.3m/min) peeling force of the release layer is 10 to 40gf/25mm, and the ratio of the low-speed (0.3m/min) peeling force (a) and the high-speed (30m/min) peeling force (b) (a/ b) is 0.3 to 4.0, and the low-speed peeling force and the high-speed peeling force are measured by peeling after attaching a standard adhesive tape.

The release layer is characterized in that it contains a polyorganosiloxane.

The base film is characterized in that the thickness is 25 to 75㎛.

The release film of the present invention has little change in peel force of the release film even when the release film is peeled and then relaminated by adjusting the composition and thickness of the release layer.

In addition, when the release film is peeled, the adhesive layer is less damaged.

1 is a schematic cross-sectional view of a release film according to an embodiment of the present invention.

Hereinafter, a release film of the present invention will be described with reference to the accompanying drawings.

1, the present invention is composed of a base film 100 and a release layer 200.

1. Base film (100)

The type of the base film 100 of the present invention is not limited. Polyester film, polyethylene film, polypropylene film, polyvinyl film, polycarbonate film, paper, etc. may be used. However, it is preferable to use a polyester film having excellent optical transparency and easy operation.

The thickness of the base film 100 is used in various types from 20 µm to 150 µm, but it is preferably 25 to 75 µm in consideration of ease of operation. If the thickness is less than 25㎛, there is a problem that it is vulnerable to external pressing (dent) and wrinkles occur during processing. If it exceeds 75㎛, the weight of the film increases, and as a result, production is degraded by exceeding the general equipment weight limit, and the film is pressed inside the roll (near the core) and deformed due to the increase in the residual stress inside the film. have.

In order to increase the adhesion between the base film 100 and the release layer 200, surface treatment may be performed on one side or both sides of the base film 100. In general, it is possible to improve adhesion with the base film 100 after coating the release layer 200 through treatments such as primer treatment, corona discharge, plasma discharge, etc., and there is no problem in implementing the release characteristics even without surface treatment.

2. Release layer (200)

The release layer 200 of the present invention is formed by applying a release composition including a release agent, a crosslinking agent, and a catalyst to one surface of the base film 100.

Silicone-based, fluorine-based, polyolefin-based and the like can be used as the release agent, but in the present invention, a silicone-based release agent was used. The crosslinking reaction of the silicone-based mold release agent includes an addition reaction type, a condensation reaction type, and an ultraviolet curing type, and can be selected and used depending on the manufacturing equipment and environment used. Typically, the addition reaction type silicone-based release composition is composed of a polyorganosiloxane, a crosslinking agent containing SiH, and a catalyst. The crosslinking reaction is performed through the addition reaction of the alkenyl group contained in the polyorganosiloxane and SiH of the crosslinking agent. As a catalyst, platinum, rhodium, ruthenium chelate compounds, and the like are used. The content of the metal component in the catalyst is about 100 to 5000 ppm of the content of the silicone release agent and crosslinking agent. In addition, a reaction retardant is included to prevent the silicone-based release agent from being cured or gelled before processing. If necessary, an antistatic agent, an antioxidant, an antifouling coating agent, etc. may be added.

In the present invention, an addition reaction-type silicone-based release agent was used, and the addition reaction-type silicone polyorganosiloxane contains 0.01 to 0.1 mol/100 g of an alkenyl group. The alkenyl group is a vinyl group, a hexenyl group, an aryl group, an octenyl group, and the like. If the alkenyl group content is high, it may remain after the curing reaction and react with the pressure-sensitive adhesive, so it is preferable to adjust the content to an appropriate amount.

Crosslinking agents include organohydrogen polysiloxanes. For the crosslinking reaction, the number of hydrogen atoms contained in the organohydrogen polysiloxane needs to be 1 or more times the alkenyl group contained in the polyorganosiloxane composition, and is preferably 1 to 3 times. When the number of hydrogen atoms contained in the crosslinking agent is excessive, a crosslinking reaction occurs with the adhesive component, so a range of 1 to 3 times is appropriate.

In order to increase the peeling force, organopolysiloxane may be added as a peeling force control agent, which is a resin having an MQ silica structure, and when added, the elasticity of the release layer 200 is reduced and the interaction with the pressure-sensitive adhesive increases, thereby increasing the peeling force.

In addition to using the peeling force adjusting agent to adjust the peeling force, the content of the alkenyl group and the crosslinking agent of the polyorganosiloxane may be adjusted or the thickness of the release layer 200 may be adjusted. The polyorganosiloxane composition is usually prepared at a 30% solvent dilution ratio, and includes 1 to 5 parts by weight of a crosslinking agent and a peel force control agent based on 100 parts by weight of the polyorganosiloxane. The peeling force adjusting agent may be added according to the required peeling force level. Polyorganosiloxane itself has a high viscosity of 5000 to 20000 cp and has a problem in coating processing. Therefore, it is preferable to dilute it with an organic solvent so as to be suitable for application and lower the viscosity to a range of 1 to 10 cp. Examples of organic solvents include aromatic and aliphatic hydrocarbon-based solvents such as toluene, xylene, benzene, hexane, heptane, and octane, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone, and a single solvent is used or It is also possible to mix and use according to the application method.

As a method of applying the release composition to the base film 100, known methods such as gravure roll coating, slot die coating, reverse roll coating, and air knife coating may be employed. A hot air drying method is used. During drying, the higher the curing temperature, the shorter the curing time, but it is better to cure the release film in an appropriate time so as not to deform. Preferably, drying conditions of 5 seconds to 40 seconds at 80 to 180°C are suitable.

It is preferable that the thickness of the release layer 200 formed after the coating and drying is 40 to 500 nm. If it is less than 40 nm, a uniform coating distribution cannot be formed on the entire surface of the base film 100, causing partial variation in peeling force, and if it exceeds 500 nm, the curing characteristics of the release layer 200 deteriorate, resulting in uncured polyorganosiloxane. After lamination with the adhesive layer, a small amount of transfer to the adhesive surface is caused.

As a method of adjusting the thickness of the release film release layer 200, a conventional method of adjusting the solid content of the coating liquid can be used, but in this case, when the solid content is high, the viscosity of the coating liquid may increase, leading to a decrease in workability. . Alternatively, the operating conditions of the coating equipment can be adjusted. In the case of gravure roll coating, it is possible by changing the circumferential speed of the gravure roll or by adjusting the volume ratio of the gravure roll. In slot die coating, the amount of coating can be controlled by adjusting the width or spacing of the die. The optimum conditions are found by controlling the solid content of the coating liquid and operating conditions of the coating equipment. In the present invention, the mesh was changed to control the volume ratio of the gravure roll by the gravure roll coating method, and in parallel, the solid content was tested for each level to obtain a desired coating amount. The method of measuring the coating amount was quantitatively analyzed for the silicon content of the coating layer using XRF (X-ray fluorescence) analysis. XRF analysis is most commonly used when analyzing the coating thickness of the release layer 200, and in addition, the coating thickness can be analyzed through XRD, SEM-EDX, TEM analysis, and the like.

3. Release film

Factors determining the peeling force of the release film are the degree of crosslinking of the release layer 200, the fluidity, and the reactivity of the silicone composition functional group and the adhesive layer of the release layer 200. During the first lamination, a reaction occurs between the release layer 200 and the adhesive layer, and the adhesive penetrates into the surface of the release layer 200 and changes the surface of both layers. Therefore, when relaminating after peeling, peeling force increases and surface damage of the adhesive layer occurs. Accordingly, as the surface damage of the adhesive layer increases, the peeling force increases during secondary peeling after re-lamination. In addition, damage to the surface of the adhesive layer may cause a problem of the appearance quality of the product.

There is a method of increasing the surface hardness of the release layer 200 by improving the degree of crosslinking in order to minimize the surface change of the release layer 200 during the first peeling. However, this may reduce the surface change of the release layer 200 of the release film during the first peeling, but the degree of crosslinking may increase, resulting in heavy peeling characteristics. This may exhibit a peel force of 50 to 200 gf/25 mm, which exceeds the light peeling range of 10 to 40 gf/25 mm, which is commonly used in adhesive products. In the present invention, characteristics were implemented for a release film corresponding to a peel force of 10 to 40 gf/25 mm during light peeling, which is most widely used in adhesive products. Currently, peeling force of less than 10gf/25mm is difficult to secure physical properties and quality with a release film applied with a silicone release agent, and a range exceeding 40gf/25mm is less demanded in displays and general adhesive products.

By controlling the composition and thickness of the release layer 200, the release film of the present invention secures a peeling force in the above range, thereby improving the problem that the peeling force increases during secondary peeling after re-bonding with an adhesive. After applying the adhesive to the release film having the above range of peeling force, the peeling force (A) and the peeled release film at the first peeling at a peeling rate of 0.1 to 30m/min are re-laminated with the pressure-sensitive adhesive, and then at the same speed. It is characterized in that the ratio (B/A) of the peel force (B) at the time of secondary peeling is 0.5 to 3.0. If the ratio (B/A) is less than 0.5, it is difficult to derive experimentally, and if the ratio (B/A) exceeds 3.0, the peeling characteristics of the release film are greatly changed, thereby increasing the surface damage of the adhesive layer.

The low-speed (0.3m/min) peeling force of the release layer 200 is 10 to 40gf/25mm, and the ratio of the low-speed (0.3m/min) peeling force (a) and the high-speed (30m/min) peeling force (b) It is characterized in that (a/b) is 0.3 to 4.0. In fact, since it is difficult to measure the film strength and crosslinking degree of the release layer, and it is inaccurate even if it is measured, the low-speed peeling force and the high-speed peeling force were measured as corresponding characteristics. The higher the peel force value, the higher the degree of crosslinking tends to be. By controlling the ratio (a/b) to 0.3 to 4.0, the change in the peeling force of the release film is small even when the release film is relaminated after peeling, and the damage to the adhesive layer during peeling is reduced. The low-speed peeling force and high-speed peeling force are measured by attaching a standard adhesive tape and leaving it for 24 hours at room temperature and then peeling the tape.

Hereinafter, the present invention will be described in more detail through examples. This is the foot

In order to explain the name more specifically, the scope of the present invention is to these Examples

It is not limited.

< Example 1-7 and Comparative example >

For the production of the release film, a 38 μm-thick polyester film (Toray Advanced Materials, XD500) was used as the base film 100. After making a release composition having the mixing ratio of Table 1, it was applied to the base film 100 by the gravure coating method. The coating thickness was adjusted using various gravure roll meshes.

As an adhesion processing process, the adhesive composition having the blending ratio of Table 2 was applied to the release film prepared in Table 1 by the gravure coating method, and after drying, a 50 μm-thick protective film (Toray Advanced Materials, XD500P) was laminated at room temperature. . The coating thickness of the adhesive composition was adjusted to 50㎛ after drying by adjusting the mesh of the gravure roll. Both the release film and the adhesive film were dried by a heat drying method.

Mixing ratio (% by weight) Ingredients Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Silicon main material
(Shin-Etsu Corporation KS847
Solid content 30%)
5.80
5.80
5.80
5.80
5.80
5.80
5.80
5.80 catalyst
(Shin-Etsu Pt-based catalyst) 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 Crosslinking agent
(Shin-Etsu Corporation X-92-122) 0.00 0.12 0.18 0.18 0.19 0.23 0.23 0.19 Solvent (toluene) 93.9 93.8 93.7 93.7 93.7 93.7 93.7 93.7 Total amount 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Gravure roll mesh (burn) 150 150 150 200 200 150 200 200

Ingredients Mixing ratio (% by weight) Acrylate resin
(Toyo Ink EX332, 30% solid content) 43.5 Hardener (Toyo Ink Co., Ltd. BK432) 0.5 Solvent (toluene) 56 Total amount 100

The following physical properties were evaluated for the Comparative Examples and Examples, and are shown in Tables 3 and 4.

(1) Primary peeling force (A)

The release film on which the adhesive film was laminated was aged at room temperature for 1 day after processing.

Thereafter, the film was sampled with a width of 2 inches and a length of 150 mm. The peel force meter was peeled off at 180° for each peeling speed using the AR-1000 of Chem-instrument.

(2) Secondary peeling force (B)

The release film on which the adhesive film was laminated was aged at room temperature for 1 day. Thereafter, the film is sampled with'width 20 cm x length 20 cm', and peeled by hand at a speed of about 10 m/min. Immediately after peeling, re-laminate at room temperature using a small laminating machine. The re-laminated release film was aged at room temperature for 1 day. Thereafter, the film was sampled in a width of 2 inches X 150 mm in length. Using Chem-instrument's AR-1000 as a peel force meter, the release film was peeled at 180° for each peeling speed. The ratio (B/A) of the secondary peeling force (B) to the primary peeling force (A) was considered to be 3.0 or less as good.

(3) Damage to the adhesive surface

After the second peeling, the adhesive side was sampled as'width 1 cm x length 1 cm'. Using a microscope, count the number of areas where irregularities of 50㎛ or more occurred on the adhesive surface. What had two or less irregularities was considered favorable.

(4) Low-speed peeling force (a), High-speed peeling force (b)

The release films produced through Comparative Examples and Examples 1-7 were sampled with'width 2 inches X length 150 mm'. A standard adhesive tape (product name tesa7475, width 1 inch) on the release layer 200 was reciprocated once using a roller weighing 1.5 kg, and then aging at room temperature for 1 day after lamination. Using Chem-instrument's AR-1000 as a peel force meter, the standard adhesive tape was peeled at 180° for each peel rate.

(5) Coating thickness

As a method of quantitatively analyzing the silicon content of the release film release layer 200, XRF was used, and in this experiment, ZSX-mini of Rigaku was used. After sampling the release film using a cutter, it was quantitatively analyzed using XRF. After making a calibration curve using a sample whose application amount was verified in advance, quantitative analysis was performed on the sample.

(6) residual adhesion rate

① Sample peeling force (C)

The release films produced through Comparative Examples and Examples 1-7 were sampled with'width 2 inches x length 150 mm'. After that, the standard adhesive tape (product name tesa7475, width 1 inch) is laminated on the release layer by reciprocating once using a rubber roller with a weight of 1.5 kg, and then left at 60° C. for 20 hours, and then the standard adhesive tape is peeled off. The peeled standard adhesive tape was laminated to a SUS plate using a rubber roller having a weight of 1.5 kg, and then aged at room temperature for 1 hour. The sample peeling force (C) was measured by peeling the standard adhesive tape at 180° using an AR-1000 manufactured by Chem-instrument as a peel force measuring instrument.

② Standard sample peeling force (D)

The Teflon coating film was sampled as'width 2 inches x length 150 mm'. A standard adhesive tape (product name tesa7475, width 1 inch) is laminated to the Teflon coating layer by reciprocating once using a rubber roller with a weight of 1.5 kg, and then allowed to stand at 60° C. for 20 hours and then peeled off the standard adhesive tape. The peeled standard adhesive tape was laminated to a SUS plate using a rubber roller having a weight of 1.5 kg, and then aged at room temperature for 1 hour. The standard sample peeling force (D) was measured by peeling the standard adhesive tape at 180° using Chem-instrument's AR-1000 as a peel force measuring instrument. The measured peel force is calculated as follows.

Residual adhesion (%) = (Sample peeling force (C) / Standard sample peeling force (D)) X 100

Exfoliation
speed Measure
Item demand
quality compare
Yes practice
Example 1 practice
Example 2 practice
Example 3 practice
Example 4 practice
Example 5 practice
Yes 6 practice
Yes 7

0.1
(m/min)

Primary peeling force
(A, gf/25㎜) 5.1 4.9 5.5 4.3 6.0 3.9 5.9 3.7 Secondary peeling force
(B, gf/25㎜) 2.4 2.7 5.9 9.0 16.7 13.6 34.7 27.5 Peel force ratio
(B/A) 3.0
Below 0.5 0.6 1.1 2.1 2.8 3.5 5.9 7.4 Adhesive surface damage
(Number of irregularities/㎠) 2
Below 0 0 0 0 0 3 11 21

0.3
(m/min)

Primary peeling force
(A, gf/25㎜) 6.3 5.9 7.2 8.1 7.6 5.8 6.3 5.1 Secondary peeling force
(B, gf/25㎜) 3.1 3.2 6.9 15.4 16.4 21.5 22.0 28.4 Peel force ratio
(B/A) 3.0
Below 0.5 0.5 1.0 1.9 2.2 3.7 3.5 5.6 Adhesive surface damage
(Number of irregularities/㎠) 2
Below 0 0 0 0 0 5 18 24

30
(m/min)

Primary peeling force
(A, gf/25㎜) 11.4 10.8 9.9 12.2 9.7 9.5 10.7 8.0 Secondary peeling force
(B, gf/25㎜) 5.3 6.9 11.0 18.4 20.7 33.7 38.4 28.1 Peel force ratio
(B/A) 3.0
Below 0.5 0.6 1.1 1.5 2.1 3.5 3.6 3.5 Adhesive surface damage
(Number of irregularities/㎠) 2
Below 0 0 0 0 One 6 27 25

When the peeling force after the first and second lamination with the adhesive film is checked, when the ratio (B/A) of the first peeling force (A) and the second peeling force (B) is 0.5 to 3.0, It was confirmed that there was little damage. Through the above analysis, when the peel force ratio (B/A) exceeds 3.0, it can be predicted that the damage to the adhesive surface will increase.

evaluation
Item Exfoliation
speed demand
quality compare
Yes practice
Example 1 practice
Example 2 practice
Example 3 practice
Example 4 practice
Example 5 practice
Yes 6 practice
Yes 7 Coating thickness (nm) 103 99 98 73 48 101 62 51 Slow peeling force
(a, gf/25mm) 0.3
(m/min) 40
Below 11.2 13.4 12.8 15.6 20.3 20.5 23.6 25.3 High speed peeling force
(b, gf/25mm) 30
(m/min) 39.2 30.6 32.8 15.8 5.3 8.8 7.8 5.6 Peel force ratio (a/b) 0.29 0.44 0.39 0.99 3.83 2.33 3.03 4.52 Residual adhesion rate
(%) 90
More than 91 93 92 94 98 90 93 97

When the coating thickness was 40 to 500 nm, the low-speed peeling force was 40 gf/25 mm or less, exhibiting light peeling characteristics, and the residual adhesion rate was more than 90%. If the residual adhesion rate is less than 90%, the component of the release layer 200 may be transferred to the pressure-sensitive adhesive, so the adhesive maker typically requires a residual adhesion rate of 90% or more. By analogy with the above results, it can be predicted that the thicker the coating thickness, the lower the residual adhesion rate.

Examples 1 to 4 satisfying the required quality in the peeling force ratio (B/A) of Table 3 and the adhesive surface damage items are the ratio of the low-speed peeling force (a) and the high-speed peeling force (b) in Table 4 (a/ b) was confirmed to be 0.3 to 4.0.

100: base film
200: release layer

Claims (4)

In the release film,
Base film;
A release layer applied to at least one surface of the base film; Including,
After applying the adhesive to one side of the release film, the peeling force (A) at the time of peeling at a peeling rate of 0.1 to 30m/min and the peeling force at the same speed after re-laminating the peeled release film with the adhesive (B) a release film, characterized in that the ratio (B / A) is 0.5 to 3.0. The method of claim 1, wherein the release layer has a low-speed (0.3m/min) peeling force of 10 to 40gf/25mm, a low-speed (0.3m/min) peeling force (a) and a high-speed (30m/min) peeling force (b ) The ratio (a/b) is from 0.3 to 4.0, and the low-speed peeling force and the high-speed peeling force are measured by peeling after attaching a standard adhesive tape. The release film according to claim 1, wherein the release layer comprises polyorganosiloxane. The release film of claim 1, wherein the base film has a thickness of 25 to 75 μm.

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