KR102095543B1 - Release film - Google Patents

Abstract

The present invention is a polyester base film; A release layer applied to one surface of the base film and including a silicone resin; Containing, when the release film is attached to the adhesive layer and then peeled at a rate of 0.1 to 10 m / min, the ratio (A / B) of the initial peel force maximum value (A) and the driving peeling force (B) is 9.0 or less The film is disclosed.
According to the release film of the present invention, when the release film attached to the adhesive layer is punched, the distal end portion of the punched surface does not peel off from the adhesive layer, so that the peeling defect does not occur in the punching process.

Description

Release film {Release film}

The present invention relates to a release film, and more specifically, by adjusting the ratio (A / B) of the initial peel force maximum value (A) and the driving peeling force (B) of the release film to a predetermined range, to the adhesive layer after punching The present invention relates to a release film having stable peelability by preventing a phenomenon in which the attached release film is lifted.

In the adhesive process, the release film is used as a base film for applying a liquid adhesive or used to protect one side of the adhesive layer by laminating with a secondary paper after applying the adhesive.

The polarizing plate is composed of a protective film, a TAC film, an adhesive layer, and a release film. The structure may be different depending on the request, but a release film is essential for the protection of the adhesive layer. Generally, a polarizing plate is prepared by applying a pressure-sensitive adhesive to a release film, laminating it on a TAC film, and then attaching a protective film. In order to attach the polarizing plate to the final product, the release film is punched to fit the module size. At this time, the release film on the punched surface should not be peeled off the adhesive layer.

However, the release film usually includes a release layer of a thin film in which fluorine or silicone components are crosslinked, so there is a problem in that it is peeled off at the end due to external impact, temperature, humidity, and the like because it is not durable.

Republic of Korea Patent Publication No. 2012-0044528 by containing a silicone resin, a polyol and a catalyst containing a polyorgano siloxane and hydrogen siloxane, while maintaining the physical properties such as peel strength, the surface is inert and excellent adhesion to the base film A separate surface activation process is not required, and a silicone release coating composition having excellent storage stability and residual adhesiveness and a release film using the same are disclosed. However, there is no disclosure to improve the peeling phenomenon of the punched end portion when the release film is punched.

Republic of Korea Patent Publication No. 2012-0044528

An object of the present invention is to provide a release film having a stable release property at the end of the punched out portion when the release film is punched after being laminated to an adhesive layer.

The release film of the present invention for achieving the above object is a polyester base film; A release layer applied to one surface of the base film and including a silicone resin; And, when the release film is attached to the adhesive layer and peeled at a rate of 0.1 to 10 m / min, the ratio (A / B) of the maximum initial peel force (A) and the driving peeling force (B) is 9.0 or less. It is characterized by.

At this time, the maximum value of the initial peeling force (A) is 90 gf / 25 mm or less, and the driving peeling force (B) is 3 to 10 gf / 25 mm.

At this time, the release amount of the release layer is characterized in that 0.03 to 0.40g / ㎡.

At this time, the release layer is characterized in that it further comprises a polyorganosiloxane and a platinum catalyst.

According to the release film of the present invention, when the release film attached to the adhesive layer is punched out, the end portion of the punched surface does not peel off from the adhesive layer, so that the peeling defect does not occur in the punching process.

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

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

As shown in Figure 1, the release film of the present invention includes a base film 100 and a release layer 200.

1. Substrate film (100)

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

In order to increase the adhesion between the base film 100 and the release layer 200, surface treatment may be performed on one or both surfaces of the base film 100. After coating the release layer 200 through a treatment such as primer treatment, corona discharge, plasma discharge, etc., adhesion to the base film 100 can be improved, and there is no problem in realizing release characteristics without surface treatment.

2. Release layer (200)

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

As the release agent, silicone-based, fluorine-based, polyolefin-based, or the like can be used, but a silicone-based release agent is preferred. The crosslinking reaction of the silicone-based release agent includes an addition reaction type, a condensation reaction type, and an ultraviolet curing type, and can be selected and used according to the manufacturing equipment and environment used.

The silicone-based release composition of the addition reaction type suitable for the present invention is composed of a polyorganosiloxane, a polyorganosiloxane crosslinking agent containing SiH, an additive and a catalyst. The crosslinking reaction is performed through the addition reaction of the vinyl group contained in the polyorganosiloxane and SiH of the crosslinking agent. As the catalyst, platinum, rhodium, or ruthenium chelate compounds may be used. The content of the metal component in the catalyst may be about 100 to 5000 ppm of the silicone release agent and crosslinking agent content. In addition, the silicone-based release agent may include a reaction retardant and an additive to improve adhesion to prevent curing or gelling in advance before processing.

As a method of applying the release composition to the base film 100, a known method such as a gravure roll coating method, a slot die coating method, a reverse roll coating method, or an air knife coating method can be employed. The hot air drying method is mainly used. The higher the curing temperature during drying can be cured in a short time, but it is better to cure the release film at an appropriate time so that it does not deform.

The release amount of the release layer 200 is preferably 0.03 to 0.40 g / m 2 after drying. When the coating amount is less than 0.03 g / m 2, there is a problem that the release property of the release layer does not appear uniformly, and when it exceeds 0.40 g / m 2, the residual material on the surface of the release layer is transferred to the uncoated surface.

3. Release film

When the release film of the present invention is attached to the adhesive layer and peeled at a rate of 0.1 to 10 m / min, the ratio (A / B) of the maximum initial peel force (A) and the subsequent peeling force (B) is 9.0 or less. It is characterized by.

The adhesive layer may be formed by applying an adhesive composition to a release film, and the coating method may be applied to a heat curing or ultraviolet curing method using a slot die, gravure, comma coater, or the like.

The adhesive composition may include various acrylic copolymers and epoxy curing agents or isocyanate curing agents. The acrylic copolymer is composed of a main monomer that provides tackiness, a comonomer that provides cohesiveness, and a functional group-containing monomer that provides tackiness and forms a crosslinking point. As the main monomer, an acrylic acid alkyl ester is usually used, and examples include n-butyl acrylate, 2-ethylhexyl acrylate, iso-octyl acrylate, and iso-nonyl acrylate. As the comonomer, a monomer capable of copolymerizing with a main monomer such as an acrylic acid ester, an alkyl methacrylate ester, vinyl acetate, styrene, and acrylonitrile is used. The functional group-containing monomer forms a crosslinking point of the pressure-sensitive adhesive, improves adhesion, and includes a carboxyl group-containing monomer such as acrylic acid and methacrylic acid, a hydroxyl group-containing monomer, an epoxy group-containing monomer, and an amino group-containing monomer.

The adhesive composition may include 1 to 5 parts by weight of a curing agent relative to 100 parts by weight of the acrylic copolymer.

The initial peeling force maximum value (A) and the driving peeling force (B) are laminated at a rate of 0.1 to 10 m / min after laminating and punching the release film of the present invention with an adhesive layer having an adhesive strength of 10 N / 25 mm or less. It was measured while doing. The maximum initial peel force (A) is the maximum value of the peel force measured from the point where the release film of the punched surface starts to peel off to the point of 20 mm, and the driving peeling force (B) is the peel force measured after the 20 mm point It is the average value of.

It is preferable that the ratio (A / B) of the maximum initial peel force (A) and the driving peeling force (B) is 9.0 or less. If the ratio exceeds 9.0, there is a problem in that a release phenomenon occurs in the release film when punching.

In addition, the maximum initial peel force (A) is preferably 90gf / 25mm or less. When the maximum initial peel force (A) exceeds 90 gf / 25 mm, the difference from the running peel force (B) increases, which may cause a problem of reverse peeling or damage to the adhesive layer, and poor workability.

In addition, the driving peeling force (B) is preferably 3 to 10gf / 25mm. If the driving peeling force (B) is less than 3 gf / 25 mm, there is a problem that the mold release force is low and peeling occurs during the handling process, and when it exceeds 10 gf / 25 mm, there is a workability problem, so the above range is good.

The above properties can be achieved by controlling the coating thickness, coating process and silicone hardness of the release layer 200. The surface hardness may be weakened by lowering the content of the crosslinking agent included in the release layer 200, but in this case, it is not preferable because it may affect adhesion due to uncuring.

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

For the purpose of explaining the name in more detail, the scope of the present invention is not limited to these examples.

< Example  1-2 and Comparative example >

For the production of the release film, a 38 µm thick polyester film (Toray Advanced Materials, XF60L) was used as the base film. After preparing the release composition having the mixing ratio of Table 1, it was applied to the base film by a gravure coating method. The coating thickness was adjusted using various gravure roll meshes. In order to control the peeling force range of the release film, the content and coating thickness of the crosslinking agent in the release composition were adjusted.

As an adhesive processing process, an adhesive composition having a blending ratio of Table 2 below was applied to the release film prepared above by gravure coating and thermally dried.

Mixing ratio (g) Ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 Ingredient Example 1 Example 2 Silicon main material A 1.5 5 Silicone main material C 5.5 4 Silicon main material B 5 3.5 Crosslinker A 0.1 0.1 0.1 Crosslinker C 0.03 0.03 Crosslinker B 0.1 0.1 Additive A 0.05 0.05 Peeling power regulator A 0.6 Peeling power regulator B 1.0 1.0 Catalyst A 0.2 0.2 0.2 Catalyst B 0.1 0.1 menstruum 100 100 100 menstruum 100 100 Gravure roll mesh A A A Gravure roll mesh B A

Ingredient Mixing ratio (% by weight) Mixing empty (% by weight) Acrylate resin (Toyo Ink EX332, solid content 30%) 39.5 49.5 Crosslinking agent (BK432, Toyo Ink) 1.0 1.0 Solvent (toluene) 59.5 49.5

The following physical properties were evaluated for the comparative examples and examples, and the results are shown in Table 3.

(1) Initial peeling force maximum (A) and running peel force (B)

The release film laminated with the adhesive layer was aged at 50 ° C for 1 day after processing. After that, it was sampled (bunched) with a width of 2 inches and a length of 150 mm to measure peel force.

The peeling force measuring device was used by Chem-instrument AR-1000, and the release film was peeled at an angle of 180 ° at 0.1 to 10 m / min. At this time, the maximum value (A) of the initial peeling force measured from the point where the release film of the punched surface is peeled to the point of 20 mm is measured. In addition, the average value B of the driving peeling force measured thereafter is measured.

(2) Ratio of the maximum peeling force (A) and the driving peeling force (B)

The sum / negative determination is made based on whether the ratio (A / B) of the maximum peeling force (A) and the initial peeling force (B) satisfies the range of 9.0 or less.

(3) Amount of release layer applied

As a method of quantitatively analyzing the silicon content of the release film release layer, XRF is usually used, and in this experiment, Rigaku's ZSX-mini was used. The release film was sampled using a cutter and quantitatively analyzed using XRF. After the calibration curve was made using a sample whose amount of application was verified in advance, quantitative analysis was performed on the sample.

(4) Excitation

After the application of the acrylic adhesive to the base film, the release film is laminated, and is punched according to the size of the device to be attached to the display device. At this time, depending on the initial peeling force of the release film, wrinkles (floating) in the shape of a window frame or a thread may occur in the adhesive layer, and it is checked whether the wrinkles are generated.

O: In the case of wrinkles (floating) in the shape of window frames or threads

X: When the wrinkles (floating) in the shape of a window frame or a thread did not occur

Properties Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Release layer coating amount (g / m ² ) 0.093 0.076 0.079 0.240 0.092
Longitudinal
(MD)
Maximum initial peeling force (A) (gf / 25mm) 44.4 35.6 50.9 29.5 32.1 Peeling force (B) (gf / 25mm) 4.0 4.0 5.6 3.5 5.1 Peeling Power Ratio (A / B) 11.1 8.9 9.1 8.4 6.3
Transverse
(TD)
Maximum initial peeling force (A) (gf / 25mm) 63.8 44.1 37.2 44.1 36.9 Peeling force (B) (gf / 25mm) 5.2 4.5 5.7 4.9 5.6 Peeling Power Ratio (A / B) 12.3 9.8 6.5 9.0 6.6 Excitation O O O X X

Looking at Table 3, the release film of Example 1, 2, when peeling in all directions, the ratio of the initial peeling force maximum value (A) and the driving peeling force (B) ratio (A / B) of stable property changes in the range of 9.0 or less The region was satisfied, and it was confirmed that the release of the release film in the above range did not occur.

100: base film
200: release layer

Claims (4)

In the release film,
Polyester base film;
It is applied to one surface of the base film, a release layer comprising a silicone resin; includes,
The release layer is composed of 4 to 5.5 parts by weight of a silicone resin made of polyorganosiloxane and 0.1 parts by weight of a platinum catalyst compared to 100 parts by weight of a solvent,
When the release film is attached to the adhesive layer and peeled at a rate of 0.1 to 10 m / min, the maximum value (A) of the initial peel force measured from the point where the release film of the punched surface is peeled to 20 mm is 90 gf / 25 mm or less , And when the average value (B) of the driving peeling force measured after the 20 mm point is 3 to 10 gf / 25 mm,
With respect to the longitudinal and transverse directions of the release film, the ratio (A / B) of the maximum initial peel force (A) and the driving peeling force (B) satisfies 9.0 or less, so that the peelability at the distal end is stable. Release film. delete The release film according to claim 1, wherein the release amount of the release layer is 0.03 to 0.40 g / m 2. delete

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