KR20150051913A - Protective film for display panel and method for3 manufacturing the same - Google Patents

Abstract

The present invention relates to a protective film for a display panel cover glass and a manufacturing method thereof and, more specifically, a protective film for improving not only physical properties but also productivity and usability wherein the protective film comprises a transparent base film layer; an impact absorbing layer stacked on the base film layer; a silicon adhesive layer formed on the impact absorbing layer; and a release layer laminated on the silicon adhesive layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a protective film for protecting a display panel cover,

The present invention relates to a protective film for protecting a display panel cover and a method of manufacturing the same, and more particularly, to a protective film for a display panel cover glass which protects a cover glass of a display panel by improving physical properties, And a display panel cover glass protection film which can remarkably protect a cover glass of a display panel from physical impact without deteriorating the sharpness of the display panel cover glass protection film.

In addition to the rapidly developing semiconductor technology, there is a growing demand for display devices with improved performance.

Such a display device necessarily includes a panel made of a transparent substrate such as a glass. Such a transparent substrate is very vulnerable to impact. In addition, the cover glass for protecting the display panel is thinner and thinner than the display panel, so that it is weakened by the impact. Therefore, there is a high concern about the protection solution of the display panel. There are many studies on mobile phone cover glasses.

Conventionally, in order to maintain optical characteristics such as sharpness and transparency, it has been important to manufacture a cover glass protective film of a display panel thinly. However, if the thin film is manufactured, the optical characteristics can be maintained, but the display panel can not be sufficiently protected from physical external impact.

Korean Patent Registration No. 20-0423548 discloses a protective film for a liquid crystal display device manufactured using a film made of polyethylene terephthalate, but it is difficult to sufficiently protect the liquid crystal from physical impact.

Korean Registration Practice No. 20-0423548

The present invention improves physical properties and protects a cover glass of a display panel to prevent breakage of a display screen together with a cover glass due to impact during use of a portable display such as a portable telephone or a notebook, A method for manufacturing a display panel cover glass protection film is provided.

The present invention also provides a display panel cover glass protection film that can dramatically protect a display panel cover glass from physical impact without compromising sharpness.

According to the present invention, a transparent base film layer; An impact absorbing layer laminated on the base film layer; A silicone adhesive layer formed on the impact absorbing layer; And a releasing layer laminated on the silicon adhesive layer.

The material of the impact absorbing layer is preferably polyurethane.

It is preferable that a transparent resin layer is additionally formed between the polyurethane layer and the silicone adhesive layer. The transparent resin layer is formed to solve the difficulty of directly applying the silicone adhesive layer on the polyurethane layer immediately.

The transparent polyurethane layer is preferably composed of a two-component curing polyurethane having impact absorbing capability.

The transparent base film layer may be formed of at least one selected from the group consisting of polyester, diacetylcellulose, triacetylcellulose, acetylcellulose butylate, isobutylester cellulose, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, polystyrene, poly Amide, polyetherimide, polyacrylate, polyimide, polyether sulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, poly May be composed of any one selected from the group consisting of ether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, thermoplastic polyurethane layer (TPU) and polycarbonate The And may be made of polyester.

The transparent resin layer may be formed of at least one selected from the group consisting of polyester, diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, isobutylester cellulose, cellulose acetate, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, , Polyamide, polyetherimide, polyacryl, polyimide, polyether sulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone , Polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, thermoplastic polyurethane layer (TPU) and polycarbonate. And it is particularly preferable to be composed of polyacrylic.

Wherein the transparent base film layer comprises a polyester film comprising at least one functional coating selected from the group consisting of a hard coating, an anti-fouling coating, an anti-fingerprint coating, an oil resistant (anti-oil coating) Lt; / RTI >

Alternatively, various transparent functional films such as anti-peeling films may be used instead of the transparent base film

The functional coating may be on the side not in contact with the polyurethane layer.

On the other hand, the transparent base film may be replaced with various functional films separately prepared such as anti-peeling films.

In addition, a functional coating such as a hard coating may be applied to the other surface of the transparent base film (the surface on which the functional coating is not performed), and a corona treatment (a method of providing fine scratches on the surface of the electric spark film) A primer coating or the like can be used. The primer coating may be a urethane primer coating.

The transparent base film layer can be produced using a comma coater, a roll coater, a gravure coater, a microgravure coat, a slot die coater, or the like. The surface of the transparent film is subjected to corona treatment and primer treatment, and a surface functional coating such as a hard coating for preventing scratch is formed thereon.

An impact absorbing layer is formed on the transparent base film layer.

The impact absorbing layer is preferably made of a polyurethane layer.

For this purpose, liquid polyurethane is prepared by mixing liquid polyol and liquid isocyanate.

The liquid polyol may include at least one selected from the group consisting of a polyether polyol and a polyester polyol.

The liquid isocyanate may include at least one selected from the group consisting of TDI (toluene diisocyanate), MDI (diphenylmethane diisocyanate), HMDI (hexamethylene diisocyanate) and IPDI (isophorone diisocyanate) .

The impact absorbing layer is formed using a comma coater, a roll coater, a gravure coater, a micro gravure coater, and a slot die coater. On one side of the completed transparent base film, that is, on the side not having a protective film attached, liquid polyurethane And is crosslinked by heat. The crosslinking may be carried out by heating at 60 to 120 ° C for 4 to 10 minutes.

As described above, the film of the present invention, on which a shock absorbing layer such as a polyurethane layer is formed on a transparent base film, is used as a liquid crystal protective film since the base film (polyester film, etc.) It is possible to use a soft polyurethane which is softer than that of the thermoplastic polyurethane, and can exhibit an excellent effect on the impact absorption side. In addition, since selection of a material having excellent transparency is easy since the strength of the polyurethane is less restricted, shock absorption and transparency can be further improved as compared with a protective film using a conventional thermoplastic polyurethane. Therefore, the shock absorption can be further improved as compared with the conventional protective film in which the silicone adhesive layer is coated on the polyester film.

On the other hand, the self-adhesive force of the fully crosslinked polyurethane is not fast at attaching to the cover glass surface of the mobile phone display, and there is a problem in workability because much air bubbles remain when the adhesive is applied. In addition, it is not completely bonded and has a re-adhesion function, but it has a good late adhesive strength, which is not easy to peel off once it is bonded, and may cause damage to the film such as stretching the transparent base film layer. Therefore, if the attachment position is incorrect or is wrong, it is not easy to detach and reattach.

In order to solve such a problem, it is preferable to form a polyurethane layer on the transparent base film layer and form a silicone adhesive layer on the polyurethane layer. When the silicone adhesive layer is formed, the adhesion speed to the cover glass is increased due to adhesiveness. Moreover, it is advantageous in that it can be easily detached after once attached due to its low adhesive property.

The silicone adhesive layer is formed using a comma coater, a roll coater, a gravure coater, a micro gravure coat, a slot die coater, or the like. At this time, it is not easy to directly coat the silicone adhesive layer on the roll state fabric due to the tackiness of the polyurethane layer. Therefore, a process of separately manufacturing an adhesive layer may be performed. In this case, the silicone adhesive layer is first formed on the first release film, and the first release film of the adhesive layer is removed from the uncured polyurethane surface while adhering the adhesive layer, followed by curing.

In this case, since the completely crosslinked silicone adhesive layer does not adhere well to the polyurethane, it is preferable to further form a transparent resin layer so that the fully crosslinked silicone adhesive layer and the polyurethane layer can be adhered to each other.

For this purpose, a transparent resin is coated on the first release layer, dried, and then a silicone adhesive is applied on the first release layer to crosslink the second release layer. At this time, a transparent resin is adhered to the first release layer, which is lower than the adhesion of the second release layer adhering to the silicone adhesive layer. Therefore, the first release layer can be easily removed.

Thus, the transparent resin film from which the first release layer has been removed is adhered to the polyurethane layer, whereby the protective film of the present invention constituted in the order of the transparent base film as a whole, the polyurethane impact absorbing layer, the transparent resin, the silicone pressure- .

The transparent resin is preferably an acrylic resin or cellulose acetate, but not limited thereto, and a transparent resin surface can be used. An acrylic resin not mixed with another adhesive resin has good adhesion to both the silicone adhesive layer and polyurethane, and has excellent transparency. The thickness of the transparent resin layer is preferably 1 to 10 mu m.

On the other hand, the thickness of the transparent base film layer may be 50 to 200 탆.

The thickness of the polyurethane layer may be 100 to 500 mu m.

When the film layer is formed in the above range, the display panel can be protected remarkably from the physical impact without deteriorating the sharpness.

The polyurethane layer may be soft.

The hardness of the polyurethane layer may be 80 or less based on Shore A hardness. And more preferably 5 to 50 on the basis of Shore A hardness.

The thickness of the silicone adhesive layer is preferably 10 to 80 mu m.

In the film of the present invention having such a constitution, the transparent base film layer functions as a scratch-preventing and anti-polluting function, and the polyurethane of the impact absorbing layer performs the shock absorbing function while maintaining high transparency. Silicone adhesive improves wettability when attached, making it easier to bond quickly and gently, and to facilitate re-work, which is easy to peel off and stick to when reattached. The transparent resin layer allows the polyurethane and silicone adhesive to adhere well.

On the other hand, the release films may be a PET film formed of polyester and may have a thickness of 25 to 200 탆

According to the present invention, by introducing a material having high transparency as an impact absorbing layer, it is possible to manufacture a protective film having a thicker thickness than the conventional one. Thus, the display panel cover glass can be remarkably protected from physical impact without damaging the sharpness. In addition, the touch feeling and softness inherent to the polyurethane are transmitted through the base film, thereby providing an optimum touch feeling.

Further, the film of the present invention has a silicone adhesive layer below the impact absorbing layer and is excellent in wettability and reattachibility, and is advantageous for rework.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically showing a side cross-section of a display panel cover glass protection film according to an embodiment of the present invention; Fig.
2 is a diagram schematically showing a side cross-section of a display panel cover glass protection film according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. The objects, features and advantages of the present invention will be readily understood by the following examples. The present invention is not limited to the embodiments described herein, but may be embodied in other forms. The embodiments described herein are provided to enable those skilled in the art to fully understand the spirit of the present invention. Therefore, the present invention should not be limited by the following examples.

≪ Example 1 >

A hard coat was applied on both sides of the corona discharge treated and primer treated PET film 100 占 퐉, completely cured (crosslinked) by heat, and then a protective film (prepared by applying a silicone adhesive on a PET film 50 占 퐉 and thermosetting) Completed.

On the PET 50 μm film (first release film), which had not been subjected to corona treatment or primer treatment, a solvent was sufficiently diluted with an acrylic resin to which an adhesion enhancer or the like had not been added by a micro gravure coater, and the coating was dried to form a 5 μm dry film The silicone adhesive and the curing agent were mixed and coated with a micro-gravure coater and completely cured at 120 ° C to form a 30 탆 cured film. Thereafter, a PET 50 탆 film (second release film) was laminated on the upper and lower portions of the roll, and the film was aged in an aging chamber at an internal temperature of 50 캜 for 24 hours to form a first release film, a transparent resin, a silicone adhesive layer, A film composed of the film sequence was completed.

Further, 1000 g of the liquid polyol and 500 g of the liquid isocyanate were mixed for 20 seconds so that the bubbles were not mixed therein, and the polyurethane having a thickness of 250 탆 was coated thereon. Heat was applied at 100 캜 for 3 minutes with hot air to lose fluidity, The first release layer of the silicone adhesive layer film was removed and adhered to the polyurethane surface. The adhesion was carried out by applying pressure to the surface of the surface from which the first release film was removed with the upper and lower rollers, and the polyurethane was cured by applying heat at 100 캜 with hot air for 3 minutes, .

The first release film of the finished adhesive film layer was removed and bonded to the polyurethane layer formed as above.

Finally, a display panel cover glass protective film having a total thickness of 385 mu m and having a thickness of 250 mu m and a silicone adhesive layer having a thickness of 30 mu m was provided on the base film hard coated with 100 mu m thick PET .

≪ Example 2 >

 A hard coat was applied on both sides of the corona discharge treated and primer treated PET film 100 占 퐉, completely cured (crosslinked) by heat, and then a protective film (prepared by applying a silicone adhesive on a PET film 50 占 퐉 and thermosetting) It completes.

Then, a solvent was sufficiently diluted with an acrylic resin to which no adhesion enhancer or the like was added by a micro-gravure coater on a PET 50 μm film (first release film) which had not undergone corona treatment or primer treatment, followed by coating and drying to form a dry film of 5 μm The silicone adhesive and the curing agent were mixed and coated with a microgravure coating machine. The cured film was completely cured at 120 ° C to form a 30 탆 cured coating film, and a PET 50 탆 film (second release film) was laminated on the upper and lower rollers.

1000 g of the liquid polyol and 500 g of the liquid isocyanate were mixed for 20 seconds so that the bubbles could not be mixed, and the first release film of the completed film was removed from the 250 탆 -thick polyurethane film and heated at 100 캜 by hot air for 3 minutes (About 50%) crosslinked, and the other surface which is not hard coated with the finished base film on the surface of the viscous polyurethane was adhered to the joint portion provided with the upper and lower rollers, Heat of 100 캜 was applied by hot air for curing the applied polyurethane and allowed to stand in the atmosphere for 24 hours for aging. As a result, the liquid polyurethane was completely cured.

Thus, a display panel cover glass protective film having a total thickness of 385 mu m and having a urethane impact absorbing layer of 250 mu m thickness and a silicon adhesive layer of 30 mu m thickness on a base film hard- .

≪ Example 3 >

 A peek-resistant film having a hard coating on its surface was prepared

Then, a solvent was sufficiently diluted with an acrylic resin to which no adhesion enhancer or the like was added by a micro-gravure coater on a PET 50 μm film (first release film) which had not undergone corona treatment or primer treatment, followed by coating and drying to form a dry film of 5 μm A silicone adhesive and a curing agent were mixed and coated with a micro gravure coater. The film was completely cured at 120 ° C to form a 30-μm cured film. A 50 μm PET film (second release film) was laminated on the upper and lower rollers. And aged at 50 deg. C in the aging room for 24 hours to complete the adhesive layer film.

On the other hand, 1000 g of the liquid polyol and 500 g of the liquid isocyanate were mixed for 20 seconds so that the bubbles were not mixed, and the first release film of the completed film was removed from the polyurethane film having a thickness of 200 탆 and applied thereon. (About 50%) crosslinked to form a polyurethane layer having a viscosity of not more than 3 parts by weight, and the upper and lower rollers were pressed against the surface of the polyurethane film, Min for 10 minutes, followed by curing of the polyurethane, followed by aging for 24 hours in the atmosphere. This completely cured the liquid polyurethane.

The first release film of the finished adhesive film layer was removed and bonded to the polyurethane layer formed as above.

A peel-preventing film for protecting a display panel cover glass having a polyurethane impact-absorbing layer having a thickness of 200 mu m and a silicone adhesive layer having a thickness of 30 mu m was formed on a hard-coated anti-peeling film.

≪ Test example >

The impact absorption performance was evaluated by attaching a protective film to OLED cells of 55 mm in width and 95 mm in length. The OLED cell was placed on a flat plate made of steel and the fall angle of the OLED cell was set to 90 degrees at a specific height to drop the falling object (bearing + chain bank, 700.9 g). The results are shown in Table 1. In the following Table 1, Example 1 shows a case where the protective film prepared according to Example 1 is attached to an OLED cell, and Comparative Example 1 shows a case where no protective film is attached.

division Example 1 Comparative Example 1 Cell broken height (mm) 1590 320

As shown in Table 1, in the case of the first embodiment of the present invention, since the broken height of the cell is very high, the effect of shock absorption can be sufficiently obtained.

Claims (15)

A transparent base film layer;
An impact absorbing layer laminated on the base film layer;
A silicone adhesive layer formed on the impact absorbing layer; And
And a releasing layer laminated on the silicon adhesive layer. The method according to claim 1,
Wherein the impact absorbing layer is a polyurethane layer. The method according to claim 1,
Wherein a transparent resin layer is additionally formed between the impact absorbing layer and the silicone adhesive layer. The method of claim 3,
Wherein the transparent resin layer is an acrylic resin or a cellulose acetate. The method according to claim 1,
Characterized in that said transparent base film layer comprises one or more functional coatings selected from the group consisting of a hard coating, an anti-fouling coating, an anti-fingerprint coating, an oil-repellent coating and an anti-skid coating (blue light- Display panel cover glass protection film. The method according to claim 1,
Wherein the base film layer is a film having anti-peeling function. The method according to claim 1,
The thickness of the transparent base film layer is 50 to 200 탆,
Wherein the thickness of the impact absorbing layer is 100 to 500 mu m. The method according to claim 1,
Wherein the release layer is a PET film. Forming a transparent base film layer;
Forming an impact absorbing layer on the transparent base film layer;
Forming a silicone adhesive layer on the impact absorbing layer; And
And laminating a release layer on the silicon adhesive layer. The method of claim 9,
And forming a transparent resin layer on the opposite side of the silicone adhesive layer to which the release layer is adhered. The method of claim 10,
And forming a release layer on the transparent resin layer. The method of claim 11,
And removing the release layer on the transparent resin layer to attach the transparent resin layer to the impact absorption layer. The method of claim 9,
Wherein the impact absorbing layer is a polyurethane layer. The method of claim 9,
Wherein the transparent base film layer comprises a polyester film comprising at least one functional coating selected from the group consisting of a hard coating, an anti-fouling coating, an anti-fingerprint coating, an oil resistant (anti-oil coating) And forming a cover film on the cover film. The method of claim 9,
Wherein the transparent base film layer is a peeling-preventive film.

Images