KR20190030939A - Display panel protective film with curved surface - Google Patents

Abstract

As the display panel of a portable terminal such as a smart phone, a tablet PC, and a digital camera is gradually enlarged due to technological development, the display panel is extended to a portion adjacent to a rim portion commonly referred to as an edge, The present invention relates to a protective film for a display panel which can be curved so as to protect not only a display panel but also a side surface formed by a curved surface from an external impact by forming a curved surface having gradually curved sides. A TPU film having a silicone adhesive layer formed on a lower surface thereof, an acrylic adhesive layer formed on the upper surface of the TPU film, a PET film formed on the acrylic adhesive layer, and a hard coating layer formed on the upper surface of the PET film A body; A fluorine-coated release film adhered to a lower portion of the silicone adhesive layer on the lower surface of the TPU film of the film body; And a linear PET release film formed on the lower surface of the film body to be adhered to the upper surface of the hard coating layer and formed on the upper surface of the hard coating layer by forming a silicone mucous layer coated with silicone on the lower surface thereof. .

Description

[0001] The present invention relates to a display panel protective film,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a protective film for a display panel capable of attaching a curved surface. More specifically, the present invention relates to a protective film for a display panel, And the edge portion and the side surface (hereinafter collectively referred to as " side surface " together with the edge portion and the side surface) are gradually formed into a curved surface having a curvature, To a side surface of a display panel that can be protected from external shocks.

In general, the display panel is mounted on a mobile device such as a mobile phone, a tablet PC, and a living device widely used around living such as an ATM, an automatic ticketing device, and the like, and is contacted by a user using a finger or a special pen, So that the display panel adheres the protective film on the panel to protect it from external impact such as scratches due to such external contact.

On the other hand, mobile devices such as smart phones and tablet PCs, which are central to the daily lives of modern people, tend to increase convenience and aesthetics by gradually applying curved surfaces to users for convenience of carrying, using, and storing In recent years, mobile devices having a three-dimensional curved shape with a larger curvature than the center plane on which the display panel is disposed are widely used. Therefore, a protective film that can be attached to a flat and curved mobile device has been proposed in order to protect not only the display panel of the center of the mobile device but also curved side and back sides from external impacts.

As a conventional example, Korean Patent Laid-Open Publication No. 10-2014-0013155, entitled " Protective cover for a portable terminal made of a curved touch screen and its manufacturing method " has been proposed as an example of the invention, According to the proposal, there are provided a tempered glass, a coating layer coated on one side of the tempered glass, a print layer printed on the edge of the other side of the tempered glass, a curved surface portion curved on the print layer, A protective cover having a curved surface composed of a rubbing adhesive and a shatterproof film adhered to the rim and an optical adhesive surface is attached on the touch screen. However, since the above method employs a flat tempered glass and the edge adopts a method of attaching the protective cover to the front, it can not be employed in the curved reinforced glass, the manufacturing process is very complicated, and the protective cover As the size of the edge increases, the curved portion of the protective sheet expands to increase the gap with the edge excessively, and the shape of the edge is appropriately corresponded to the shape of the various edges. It was a disadvantage that was difficult to do.

According to another proposed method, Korean Patent No. 10-1717507, entitled " Composite protective sheet attached to a portable device having a curved portion and method of manufacturing the same, " has been proposed. According to the proposal, A polymer substrate having a transparent sheet made of glass or plastic, an adhesive layer adhered to the transparent sheet under the transparent sheet and having an adhesive layer or an adhesive layer formed on one side thereof and a transparent adhesive layer for curved surface formed on the other side, A composite protective sheet comprising a side surface and a transparent hard layer formed on the upper surface of the polymer substrate is attached to the side surface including the display panel and the rim portion of the portable device. The present invention provides a composite protective sheet for attaching a portable device, which has excellent scratch resistance, is easy to discharge bubbles, and adheres to the shape of a curved surface while overcoming a spring back phenomenon in which the film is restored to its original shape. The rim portion of the composite protective sheet according to the present invention must be precisely curved in the preforming step because the rim portion of the composite protective sheet is molded into the curved surface in advance according to the material of the polymer substrate and attached to the curved surface of the portable device. There is a problem that a curved layer is formed on a part of the upper surface of the transparent sheet and the other upper surface is exposed to the outside as it is, The sheet can be made of a material that can prevent scattering of tempered glass or plastic Scattering prevention layer. In addition, the above-mentioned method is particularly advantageous in that the transparent sheet and the polymer substrate are not laminated in the same size but the step is necessarily formed at the rim portion and the polymer substrate is not formed. The edge portion has a problem in that a precise curved surface forming step has to be performed as described above.

As described above, the protective film for protecting both the side surface of the mobile device formed with a curved surface and the central portion where the display panel including a substantially flat display panel is disposed is made of hard glass, polycarbonate, or polyester material having hardness, stiffness, transparency A protective film adhered to a part of a side surface formed of a curved surface of a mobile device in order to solve a springback phenomenon which is difficult to be molded and restored to its original shape even if it is molded, As shown in the figure, flexible TPU (thermoplastic polyurethane) is applied and the adhesive layer is formed on both sides thereof. However, soft TPU has weak hardness and is particularly vulnerable to scratches. Unexpected scratching by special pen It is hard to overcome external shock And it is a protective film which has a disadvantage in that the adhesive strength of the adhesive layer for adhering must be considerably increased.

(Prior Art 1) Korean Patent Publication No. 10-2014-0013155 (Prior Art 2) Korean Patent No. 10-1717507

The present invention has been made to solve the problems of the above-described prior arts, in particular, to solve the problem of hardness, scratch resistance and adhesion force, which are disadvantages of the TPU protective film applied to correspond to the curved surface, It is possible to stably attach to the side of the curved surface of the mobile device without laminating a step between the TPU film as the base film and the PET film as the laminated film to improve the protection function for protecting the display panel and the side surface from external impact And a hard coat layer formed on a PET film as a laminated film to form a curvilinear surface which can be adhered to a linear PET release film which is an upper release film laminated on a PET film without using a double sided tape The purpose.

The above object of the present invention can be also achieved by a TPU film comprising a TPU film as a substrate film and a silicone adhesive layer formed on the lower surface of the TPU film, wherein an acrylic adhesive layer is formed on the upper surface of the TPU film, And a hard coating layer formed on the upper surface of the PET film; A fluorine-coated release film adhered to a lower portion of the silicone adhesive layer on the lower surface of the TPU film of the film body; A linear PET releasable film formed on the lower surface of the film body by a silicone adhesive layer formed on the lower surface of the hard coating layer and adhered to the upper surface of the hard coating layer, .

Preferably, the TPU film is a TPU film having a thickness of 100 to 150 mu m.

Preferably, the PET film is a PET film having a thickness of 19 to 38 탆.

Preferably, the hard coat layer is a hard coat layer having a thickness of 2 to 5 mu m and a hardness of 2H to 4H.

Preferably, the acrylic adhesive layer for adhering the TPU film and the PET film is formed to a thickness of 5 to 15 mu m.

The curved surface-adhering display panel protective film according to the present invention has a structure in which a PET film and a hard coating layer are laminated on a TPU film as a base film to improve the hardness and scratch resistance of the TPU film, Acrylic adhesive layer and has the flexibility to overcome the springback phenomenon of the PET film due to the adhesive strength of the acrylic adhesive layer so that it can be stably attached to the curved side of the mobile device and the hard coating layer is formed on the PET film, There is an advantageous effect that the film can be laminated and laminated without using a linear PET release film and a double-sided tape which are laminated on an upper release film.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a general protective film for a curved surface-mounting display panel to which a conventional technique is applied; FIG.
2 is a schematic cross-sectional view of a protective film for a display panel according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: (Or thin) or expressed in a simplified form, but the protection scope of the present invention should not be construed as being limited.

The display panel protection film according to the embodiment of the present invention includes a film body 10 to be attached to a display panel which is a central portion of a mobile device and a side having a curvature, And a linear PET release film (30) adhered to the upper surface of the film body (10).

The TPU film 11 is formed on the lower surface of the TPU film 11. The film main body 10 includes a TPU film 11 as a base film and a silicone adhesive layer 12 as a lower surface of the TPU film 11, A PET film 14 is formed on the acrylic adhesive layer 13 and a hard coating layer 15 is formed on the upper surface of the PET film 14.

The TPU film 11 is formed of a thermoplastic polyurethane material as a base film for forming the film body 10 and is made of a transparent material. In addition to the above-mentioned TPU, a synthetic resin that can be applied as a base film of a protective film for protecting a display panel portion and side portions of a mobile device includes PET, polyethylene naphthalate, polyester sulfone, polyimide, polyarylate, polycarbonate, Acrylate, polyethylene, polypropylene and the like, but the TPU-based film is most preferred for flexibility and adhesive layer formation. The TPU film 11 has a thickness of 100 to 150 탆, which is an optimal thickness for forming. When the thickness is less than 100 탆, the TPU film 11 hardly functions as a base film. When the thickness exceeds 150 탆, This is because it may be difficult to secure the flexibility of

In this case, the thermoplastic polyurethane which is the raw material of the TPU film 11 serving as the base film should not contain any additive. The TPU film prepared by using the thermoplastic polyurethane raw material containing the additive may be formed by applying The silicone adhesive layer 12 to be described later is not cured. In this case, an acrylic adhesive layer should be used in place of the silicone adhesive layer 12, which is problematic in that the acrylic adhesive layer generates bubbles when attached to the surface of the display panel, do. Therefore, a silicone adhesive layer is formed on the TPU film 11 so as not to include additives, so that the generation of bubbles is minimized and the generated bubbles can be easily removed when attached to the surface of the display panel.

A silicone adhesive layer 12 is formed on the lower surface of the TPU film 11 and an acrylic adhesive layer 13 is formed on the upper surface.

The silicone adhesive layer 12 is formed on the lower surface of the TPU film 11 so that a fluorine-releasing film 20 described later is detachably adhered to the TPU film 11. When the thickness of the silicone adhesive layer 12 is 20 μm to 25 μm, if the thickness of the silicone adhesive layer 12 is less than 20 μm, air bubbles are formed when the silicone adhesive layer 12 is in close contact with the liquid crystal. .

The acrylic adhesive layer 13 is formed on the upper surface of the TPU film 11 so that a PET film 14 described later is laminated on the TPU film 11 to be attached thereto. When the thickness of the acrylic adhesive layer 13 is less than 5 탆, adhesion of the PET film 14 to be described later to the TPU film 11 is insufficient Particularly when the TPU film 11 is attached to the side surface of the mobile device having a curvature, a springback phenomenon may occur and the PET film 14 may be lifted from the TPU film 11, The hardness of the adhering portion increases and a phenomenon that the adhering portion is separated from the liquid crystal occurs.

The PET film 14 is stacked on the acrylic adhesive layer 13 and adhered to the TPU film 11 in a stable manner without touching the display panel and the curved surface of the TPU film 11, As shown in FIG. If the thickness of the PET film 14 is less than 19 m, wrinkles occur during the manufacturing process. When the thickness of the PET film 14 exceeds 38 m, the thickness of the PET film 14 becomes too thick, So that it is difficult to adhere to the curved surface, and even if the curved surface is adhered to the curved surface, a springback phenomenon may be caused by the separation from the acrylic adhesive layer 13.

The hard coating layer 15 is a coating layer coated on the PET film 14. When the PET film 14 is attached to the surface of a mobile device and used, external impact such as nail marks, And protects the outer surface of the display panel protective film according to an embodiment of the present invention from external impact such as scratches, marks or pencil marks, The linear PET film 30 can be directly laminated on the hard coat layer 15 without the need to adhere to the hard coating layer 15, thereby avoiding the use of the double-sided tape. The composition for forming the hard coating layer 15 may be a composition for forming a known ultraviolet curable hard coating layer, for example, an ultraviolet curable resin, a reactive fluorine compound, a photopolymerization initiator, a solvent, etc., The composition is not particularly limited as long as it is a composition, so a detailed description thereof will be omitted. If the thickness of the hard coat layer 15 is less than 2 탆, the hard coat layer 15 can not perform the function of a hard coating. If the thickness exceeds 5 탆, the hard coat layer 15 has a high hardness, This phenomenon of cracking occurs. Therefore, the hard coat layer 15 having a thickness of 2 to 5 탆 preferably has a hardness of 3H with a glass surface hardness, thereby ensuring flexibility that is not easily cracked.

As described above, the film body 10 protecting the mobile device by attaching to the side surface of the flat display panel and the curved surface of the center of the mobile device has the silicone adhesive layer 12, the TPU film The adhesive layer 11, the acrylic adhesive layer 13, the PET film 14, and the hard coat layer 15 are laminated in this order. In order to solve this problem, It is possible to easily form the curved surface without bubbles and to solve the problems of the related art by forming the pressure sensitive adhesive layer or forming the curved surface without forming the pressure sensitive adhesive layer, There will be one excellent effect.

A fluorine-releasing film 20 is adhered to a lower portion of the silicone adhesive layer 12 formed on the lower surface of the TPU film 11 of the film body 10. The fluorine-coated release film 20 is a release film to be removed when the film body 10 is attached to the surface of a mobile device, and a conventional PET film is applied thereto. The fluorine-coated release film 20 is fluorine- And is detachably attached to the silicon adhesive layer 12 formed at the lowermost part and functions to protect the film body 10 from external shocks during storage, transportation, and use. The fluorine-containing release film has a thickness of 38 to 50 탆. When the thickness is less than 38 탆, it is difficult to maintain the film shape at the time of forming, and when the thickness exceeds 50 탆, only the production cost of the release film And the effect is the same, so that there is no economical efficiency.

A linear PET release film 30 is laminated on the upper surface of the hard coat layer 15 of the film body 10. The linear PET release film 30 is a release film that is removed when the film body 10 is attached to the surface of a mobile device as in the case of the fluorine release film 20. The conventional PET film is applied to the linear PET release film 30, 31) is detachably attached to the hard coating layer 15 formed on the upper portion of the film body 10 and protects the film body 10 from external shocks during storage, transportation and use of the film body 10 . The linear PET release film 30 has a thickness of 45 to 55 탆. If the thickness is less than 45 탆, the linear PET release film 30 is insufficient in thickness for protecting the external impact. If it exceeds 55 탆, The coating thickness of the silicon mucous membrane layer 31 becomes thick, and the thickness of the entire protective film becomes thick. The silicon mucosal layer 31 for adhering the linear PET release film 30 to the film body 10 is coated to have a coating thickness of 1 to 10 탆.

The display panel protection film according to the embodiment of the present invention can solve the scratch resistance problem of the soft TPU film to protect the display panel from external impacts such as fingernails and pen marks, A hard coat layer 15 is formed on the upper side of the film body 10 so that the upper side linear PET film 12 is formed as it is without using a separate double- (30) can be laminated on the hard coat layer (15) so as to solve the problems and inconveniences of the prior art.

Table 1 shows test items and test results for various characteristics of a protective film for a display panel according to a preferred embodiment of the present invention. The materials and processing method of the test specimen applied to this test are as follows.

The display panel protective film made of the specimen was made from a fluorine-coated release film having a thickness of 50 mu m, a silicone adhesive layer having a thickness of 25 mu m, a TPU film having a thickness of 100 mu m, an acrylic adhesive layer having a thickness of 10 mu m, A hard coat layer having a thickness of 2 to 4 占 퐉, and a linear PET release film having a thickness of 10 占 퐉 and having a thickness of 50 占 퐉 coated on one side thereof are laminated in this order on a TPU film, The layer is applied, the film is lapped and processed, and wound uniformly around the inside diameter of 6 inches.

              Item                      Characteristics             Total thickness (탆)                    273 占 퐉 (占 19)              Transmittance (%)                     92 ± 2 (%)              Hardness (H)                      3H ± 1            Adhesion (gf / in.)   top 5 to 6 gf / in., back 150 to 200 gf / in. (sus304)            Adhesion (1,500 gf / in.)                   1,500 gf / in. More than             Heat temperature (℃)                     80 ° C / 3hrs

1. Test Method

  Test conditions: Unless otherwise specified, it shall be at room temperature (25 ± 2 ℃) and normal humidity (65 ± 20%) specified in KS A1107.

  Pretreatment: Leave at room temperature and normal for 2 hours.

2. Thickness measurement

  Test method: See KS A1107. Use standardized guage.

            1) Size of specimen

               1,080 mm (width direction) X 30 mm (length direction) X N (3)

            2) Measuring equipment

               Using Digital Thickness Gauge of 0.0001mm scale

            3) Test method

               Measure 12 points in the width direction of each sample and calculate the average value.

3. Adhesive Strength Test

  Purpose: This test is to measure adhesion of protective film for display panel. Adhesion is the force that the film will continue to adhere to the adherend, and the force (strength) that destroys the adherence by peeling off the film is measured.

  Test method: All test methods and specifications are in accordance with KS A1107.

            1) Size of specimen

               25 mm X 400 mm X N (3)

            2) Measuring instrument

               Tensile Strength Tester

            3) Test method

               The specimens cut to 25mm are attached to SUS plate (SUS304) and then reciprocated once with a 2Kg load press. Using a tensile strength tester, measure the value three times when the specimen is pulled off at a speed of 300 ± 30 mm / min.

4. Heat resistance test

            1) Size of specimen

               50 mm X 150 mm X N (3)

            2) Measuring instrument

               Drying Oven

            3) Test method

               Three specimens cut to 50 mm are attached to SUS 304, and are heated at 80 ° C for 30 minutes in a drying oven, and then cooled at room temperature for 10 minutes. Remove the specimen from the test plate and visually confirm whether the test plate has been peeled off.

5. Color

  1) Color: White

  2) Inspection: Visual inspection

6. Transmittance

  1) Size of specimen 50mm X 150mm X N (3)

  2) Measuring equipment: VL transmission VL 100

  3) The measurement shall be carried out in accordance with Korean standard KS M ISO 13468.

7. Hardness

  1) The hardness measurement shall be carried out in accordance with Korean Standard KS M ISO 15184.

8. Test Results

  As shown in Table 1, the curved surface-adhering display panel protective film according to the present invention has a transmittance of 92 ± 2%, a glass surface hardness of 3 ± 1H, an adhesion strength of 5 to 6 gf / in, 200 gf / in., Adhesion 1,500 gf / in. Or more, and a heat-resistant temperature of 80 DEG C / 3hrs.

It is possible to repeatedly manufacture the same product by the same manufacturing method in the manufacturing industry for manufacturing the protective film for protecting the display panel according to the present invention, something to do.

10: Film body 11: TPU film
12: silicone adhesive layer 13: acrylic adhesive layer
14: PET film 15: hard coat layer
20: Fluorine-coated release film
30: Linear PET release film 31: Silicone mucosa layer

Claims (4)

1. A protective film for protecting a surface of a mobile device by being attached to a flat display panel of a mobile device and a curved side surface,
The curved surface-mountable display panel protection film is characterized in that,
A TPU film 11 as a base film and a silicone adhesive layer 12 as a lower surface of the TPU film 11. An acrylic adhesive layer 13 is formed on the upper surface of the TPU film 11, A film body 10 on which a PET film 14 is formed on the acrylic adhesive layer 13 and a hard coating layer 15 is formed on the upper surface of the PET film 14;
A fluorine-coated release film 20 adhered to a lower portion of the silicone adhesive layer 12 on the lower surface of the TPU film 11 of the film body 10;
A Linear PET release film adhered onto the hard coating layer 15 of the film body 10 and formed with a silicone mucosal layer 31 coated on the lower surface thereof and adhered to the upper portion of the hard coat layer 15 30). ≪ / RTI >
The method according to claim 1,
Wherein the TPU film (11) of the film body (10) has a thickness of 100 to 150 占 퐉. The method according to claim 1,
Wherein the PET film (14) of the film body (10) has a thickness of 19 to 38 占 퐉. The method according to claim 1,
Wherein the hard coating layer (15) of the film body (10) has a thickness of 2 to 5 mu m and the glass surface hardness has a hardness of 3H.

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