KR20200084070A - Display protective film with improved smooth surface lift - Google Patents

Abstract

Disclosed is a liquid crystal protective film with an improved surface lifting phenomenon and more specifically, to a liquid crystal protective film with an improved surface lifting phenomenon, comprising: a substrate layer; a binder elastic layer formed on one surface of the substrate layer; a self-recovery layer formed on an upper surface of the binder elastic layer; a protective film layer formed on an upper surface of the self-recovery layer; a curl forming layer formed on the other surface of the substrate layer; and an adhesive layer formed on a lower surface of the curl forming layer. The liquid crystal protective film is applied to a curved surface part of a display and then improves feeling of touch by suppressing a lifting phenomenon, and a curl is formed on a side surface without forming by using contraction generated in a radical polymerization reaction so as to be applied to a curved surface part of a display with a large angle.

Description

LCD protective film with improved surface lift {DISPLAY PROTECTIVE FILM WITH IMPROVED SMOOTH SURFACE LIFT}

Disclosed is a liquid crystal protective film having improved curved surface lift, more specifically, it is applied to the curved surface of the display to improve the touch feeling by suppressing the floating phenomenon, and the side surface without forming by using shrinkage generated in the radical polymerization reaction. The present invention relates to a liquid crystal protection film having an improved curling phenomenon that can be applied to a curved portion of a large-angle display by forming an curl.

In general, the LCD protective film is used to prevent scratches on the surface of tempered glass and hard coating on the surface of smartphones or tablet PCs, which are small display devices, and to prevent damage.

Recently, both ends of the small display devices being produced are curved to make the appearance gorgeous.

However, most of the liquid crystal protective films produced in the past are adhesive products on a thick and hard film so that they can be attached to a flat surface, and thus, when applied to a curved display, there is a problem that excitation occurs in the curved portion.

This method of giving up the curved portion clearly shows the boundary between the film-attached and non-film-attached parts when attached to the display. Also, regardless of the thickness of the film, it is not possible to give a neat appearance, so many users are choosing a direction that does not stick.

In order to solve this problem, a product using a thermoplastic polyurethane, a soft material, has been developed on existing LCD protective films and can be attached to the curved surface, but this product is not easily restored due to its soft material and marks cannot be restored. It has a problem that hard coating treatment is difficult and scratches are easily generated.

That is, in view of the production process, the film using soft TPU has a very high defect rate of the product due to the insufficient optical properties of the TPU fabric itself, and the yield is greatly reduced, and the adhesive and the surface treatment are difficult due to poor surface even when coated.

In addition, its hardness and elasticity are low in actual use, and when a film is attached to a mobile phone, its marks are clearly formed even when pressed or stamped, and do not disappear. As a result of purchasing a commercially available product and applying it to a liquid crystal, there are currently products that can completely cover the curved surface, but when pasted, the pressing marks are very clear, and even if attached by hand, the air bubbles generated in the middle of the attachment can be removed. The marks are very difficult to attach and take a long time.

In addition, a method of forming and attaching a curved surface by foaming an existing rigid film at a high temperature is used. Using the forming method causes a lot of problems because the curved surface of the mobile phone is slightly different for each lot, so it is impossible to give the curved surface perfectly suited to all mobile phones by forming.

Occasionally, a product may be produced using thin PET, but in this case, the pressing mark problem is not solved, and the high hardness of PET often falls off from the curved portion. In addition, since the product is too thin, there is little protection function, so it cannot serve as a'protective film'.

Korean Patent Registration No. 10-1221441 (2013.01.07) Korean Patent Registration No. 10-1329049 (2013.11.07)

The disclosed contents are applied to the curved portion of the display to improve the touch feeling by suppressing the excitation phenomenon, and also apply to the curved portion of the large-angle display by forming curls on the side surface without forming by using the shrinkage generated in the radical polymerization reaction. It is to provide a liquid crystal protective film having an improved surface lifting phenomenon.

As one embodiment, the contents of this disclosure are formed on a base layer, a binder elastic layer formed on one surface of the base layer, a self-recovery layer formed on an upper surface of the binder elastic layer, and an upper surface of the self-restore layer. A liquid crystal protection film having improved curved surface lift, characterized by comprising a protective film layer, a curling layer formed on the other surface of the base layer, and an adhesive layer formed on a lower surface of the curling layer.

Preferably, the base layer is formed to a thickness of 25 to 100㎛, may be made of corona or primer-treated polyethylene terephthalate.

More preferably, the binder elastic layer is formed to a thickness of 30 to 300㎛, it may be formed by thermal curing or UV curing a resin containing an acrylate-based, urethane-based and urethane methacrylate-based.

More preferably, the self-recovery layer is formed to a thickness of 10 to 40㎛, may be made of a urethane mixture.

Even more preferably, the urethane mixture may be made of a urethane resin, isocyanate, curing agent and solvent.

Even more preferably, the protective film layer is self-adhesive and may be made of polypropylene or polyethylene.

Even more preferably, the curl-forming layer may include 100 parts by weight of a photocurable oligomer, 1 to 15 parts by weight of a photocurable monomer, and 1 to 15 parts by weight of a photopolymerization initiator and/or photosensitizer.

Even more preferably, the adhesive layer is formed to a thickness of 50 to 250㎛, it may be made of a transparent adhesive film for curing after ultraviolet light.

The liquid crystal protection film with improved curved surface lift as described above is applied to the curved surface of the display to improve the touch feeling by suppressing the floating phenomenon, and curling on the side surface without forming by using the shrinkage generated in the radical polymerization reaction. It forms an excellent effect of providing a liquid crystal protective film that can be applied to the curved portion of a large-angle display.

1 is an exploded perspective view showing a liquid crystal protective film with improved curvature of the disclosed surface.
FIG. 2 is a photograph showing a phenomenon of lifting the curved portion of the liquid crystal protection film manufactured through the disclosed Examples 1 and 3 and Comparative Examples 1 to 3.

Hereinafter, the preferred embodiment of the present invention and the physical properties of each component will be described in detail, but it is intended to be described in detail so that those skilled in the art to which the present invention pertains can easily implement the invention. This does not mean that the technical spirit and scope of the present invention is limited.

The disclosed liquid crystal protective film with improved surface lift is a base layer 10, a binder elastic layer 20 formed on one surface of the base layer 10, and a self-recovery formed on an upper surface of the binder elastic layer 20. The layer 30, the protective film layer 40 formed on the upper surface of the self-recovery layer 30, the curl forming layer 50 formed on the other surface of the base layer 10, and the lower part of the curl forming layer 50 It consists of an adhesive layer 60 formed on the surface.

The substrate layer is a layer that serves as a substrate for the disclosed liquid crystal protective film with improved excitation, and is made of polyethylene terephthalate having a thickness of 25 to 100 µm, which improves the shape stability of the liquid crystal protective film with improved disclosed excitation to improve external force. It serves to suppress the deformation of the protective film.

At this time, the base layer 10 is more preferably made of corona or primer-treated polyethylene terephthalate. As described above, the corona or primer-treated base layer 10 has a binding force with the binder elastic layer or the curl forming layer. It can be improved to improve the peeling phenomenon.

When the thickness of the substrate layer 10 is less than 25 μm, the above effect is negligible. When the thickness of the substrate layer 10 exceeds 100 μm, the overall thickness of the liquid crystal protective film is not significantly improved. It is not desirable because it increases the manufacturing cost.

The binder elastic layer 20 is formed to a thickness of 30 to 300㎛ on one surface of the base layer 10, and is formed by thermal curing or UV curing resins containing acrylate-based, urethane-based and urethane methacrylate-based resins. , By imparting impact resistance to the improved liquid crystal protective film having improved surface lift-off phenomenon, it serves to suppress the deformation of the liquid crystal protective film from external impact.

At this time, if the thickness of the binder elastic layer 20 is less than 30 μm, the smoothness is improved, but impact resistance is lowered. When the thickness of the binder elastic layer 20 exceeds 300 μm, the impact resistance of the liquid crystal protective film is improved. The smoothness is lowered so that the binder elastic layer 20 of a uniform thickness cannot be formed.

The self-recovery layer 30 is formed to a thickness of 10 to 40 µm on the upper surface of the binder elastic layer 20, and is made of a urethane mixture, and the liquid crystal protection film is deformed from micro-scratches or external impacts and pressing phenomena. It plays a role in allowing it to be restored to its original shape later.

The urethane mixture is made of a urethane resin, an isocyanate, a curing agent, and a solvent, preferably 100 parts by weight of a urethane resin, 40 to 60 parts by weight of an isocyanate, 60 to 90 parts by weight of a curing agent, and 45 to 75 parts by weight of a solvent.

At this time, the curing agent is not particularly limited as long as it can cure the mixture consisting of a urethane resin and isocyanate, and any one can be used, but any one selected from the group consisting of benzophenone, ketone-based initiator, benzoic acid, anthraquinone and acylphosphine desirable.

In addition, the solvent is preferably made of propylene glycol methyl ether acetate (PMA, Propylene Glycol Methyl Ether Acetate) or butyl acetate (BA, Butyl Acetate).

When the thickness of the self-recovery layer 30 is less than 10 μm, the resilience to fine scratches and the like decreases. When the thickness of the self-recovery layer 30 exceeds 40 μm, the self-recovery layer is not significantly improved ( 30) In the process of forming, the curing time is excessively increased to decrease production efficiency and increase the thickness of the liquid crystal protective film.

The protective film layer 40 is formed on the upper surface of the self-recovery layer 30 to a thickness of 25 to 50 μm, and is made of polypropylene having self-adhesive property or polyethylene having self-adhesive property. ).

When the thickness of the protective film layer 40 is less than 25 μm, the protective effect on the self-recovery layer 30 is negligible, and when the thickness of the protective film layer 40 exceeds 50 μm, the self-recovery layer ( The protective effect against 30) is not significantly improved, but the thickness of the liquid crystal protective film is increased.

The curl forming layer 50 is formed to a thickness of 5 to 15 μm on the other surface of the base layer 10, 100 parts by weight of a photocurable oligomer, 1 to 15 parts by weight of a photocurable monomer, and a photopolymerization initiator and/or photosensitizer It comprises 1 to 15 parts by weight, it serves to suppress the lifting phenomenon when the disclosed liquid crystal protective film is applied to the curved portion of the display.

When the thickness of the curl forming layer 50 is less than 5 μm, the above effect is insignificant. When the thickness of the curl forming layer 50 exceeds 15 μm, the thickness of the liquid crystal protective film is not significantly improved. It is not preferable because it is excessively increased.

At this time, a thermoplastic resin, a thermosetting resin and a solvent may be additionally added to the curl forming layer 50 in order to supplement the processing properties of the coating process for forming the curl forming layer 50 and the properties of the coated curl forming component. have.

The photocurable oligomer used in the curl-forming layer 50 is a compound capable of polymerizing by radicals or cations generated by a light source such as ultraviolet light, urethane acrylate, epoxy acrylate, 　polyester acrylate, 이polyester acrylate, and 　alicyclic Epoxy, 　 aromatic epoxy, and the like. Specific examples include Japanese Chemicals UX-2201, UX7101, Cytec's EB1290, EB600, EB830, Miwon Corporation's PU2200, MU9800, and Kukdo Chemical's YD128, KDU-651.

In addition, specific examples of the monomer used in the curl forming layer 50 are 　2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 소isocarbonyl (meth)acrylate, 1,6-hexane Dioldi(meth)acrylate,　trimethylolpropanetri(meth)acrylate,　pentaerythritol tri(meth)acrylate,　dipentaerythritolpenta(meth)acrylate and dipentaerythritolhexa(meth)acrylate, etc. Can be heard.

Further, specific examples of the photopolymerization initiator used in the curl-forming layer 50 include: 　1-hydroxy cyclohexylphenylketone, 　benzyldimethylketal, 　hydroxydimethylacetophenone, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. And the like.

In addition, specific examples of the photosensitizer include n-butylamine, triethylamine, poly(n-butylphosphine), and the like. The photopolymerization initiator and/or photosensitizer may be used as a mixture of "1" or "2" or more.

In addition, as an additive used in the curl forming layer 50, a leveling agent, an antioxidant, an ultraviolet absorber, an adhesion enhancer, an intensity enhancer, an silane coupling agent, an nano metal oxide sol, etc. can be used. can do.

In addition, specific examples of the thermoplastic resin and thermosetting resin used in the curl forming layer 50 include acrylic resin, cellulose derivative, vinyl chloride resin, silicone resin, urea resin, melamine resin, epoxy resin, polyester resin, and the like. It is not limited to the types listed above.

Further, specific examples of the solvent include acetone, 　diethyl ketone, 케dipropyl ketone, 　methylethyl ketone, 　methylbutyl ketone, 　methyl isobutyl ketone, 　cyclohexanone, 　ethyl acetate, 　butyl acetate, 　ethyl cellosolve, 　butyl cellosolve, and 　propylene Glycol methyl ether, "ethanol," propanol, "butanol," toluene, and xylene can be used alone or in combination.

Amorphous monomers and oligomers, such as urethane acrylate, have a wide spread form, and polymerization reaction occurs by radicals generated by an ultraviolet light source, etc. The chains combine to form a gathering and contraction. Generally, 5~10% of volume contraction occurs. Therefore, when the amorphous monomer and the oligomer are applied to the base film and irradiated with ultraviolet rays, shrinkage may occur toward the coated surface while photopolymerization reaction occurs, thereby generating curl.

The adhesive layer 60 is formed to a thickness of 50 to 250 μm on the lower surface of the curl forming layer 50, and is made of an optically clear adhesive (OCA) after ultraviolet rays. It is formed through a method of curing by irradiating with ultraviolet rays after application in an amount of 1300 to 1500g/25mm.

The above adhesive layer not only adheres the disclosed liquid crystal protective film to the display surface, but also exhibits excellent transparency.

As described above, the adhesive layer 60 made of an optically transparent adhesive exhibits non-yellowing properties as a curable adhesive after UV light, and is low in viscosity as a solvent-free type, and has excellent permeability and wetting properties.

The liquid crystal protective film having an improved curved surface lifting structure made of the above structure is 100 parts by weight of a photocurable oligomer on one surface of a base layer 10 made of corona or primer-treated polyethylene terephthalate having a thickness of 25 to 100 μm, and a photocurable monomer 1 To 15 parts by weight of the photopolymerization initiator and/or photosensitizer 1 to 15 parts by weight of the coating for a curling mixture, and irradiated with ultraviolet rays to form a curling layer 50, with silicone release treated polyethylene terephthalate After the ultraviolet rays are coated on the surface of the release paper made of the curable optical transparent adhesive and irradiated with ultraviolet rays, an adhesive layer 60 having a thickness of 50 to 250 μm is formed, and the adhesive layer 60 is brought into contact with the curl forming layer 50 After lamination to produce a laminate, the binder elastic layer 20 formed by thermosetting or UV curing a resin containing an acrylate-based, urethane-based and urethane-methacrylate-based resin on the other surface of the base layer 10 formed on the laminated body 20 Is formed to a thickness of 30 to 300㎛, the self-recovery layer 30 made of urethane resin, isocyanate, curing agent and solvent on the upper surface of the binder elastic layer 20 is formed to a thickness of 10 to 40㎛, Self-adhesive on the upper surface of the self-recovery layer 30, and may be manufactured by a process of forming a protective film layer 40 made of polypropylene or polyethylene to a thickness of 25 to 50 μm.

Hereinafter, a method for manufacturing a liquid crystal protection film having improved disclosed surface lifting phenomenon and physical properties of the liquid crystal protection film produced through the manufacturing method will be described with reference to examples.

<Example 1>

A mixture for a curl-forming layer on one surface of a substrate layer made of a 25 µm thick corona-treated polyethylene terephthalate (photocurable oligomer (urethane acrylate) 100 parts by weight, photocurable monomer (2-ethylhexyl methacrylate) 8 parts by weight, and Coating the photopolymerization initiator (1-hydroxy cyclohexylphenyl ketone) 8 parts by weight}, and irradiated with ultraviolet rays with a UV lamp (48W/3000) to form a 75 µm-thick curl forming layer, and 50 µm-thick polyethylene with silicone release treatment. After ultraviolet rays are coated on the surface of the release paper made of terephthalate in an amount of 1400 g/25 mm after curing with ultraviolet rays, and irradiated with ultraviolet rays to form an adhesive layer having a thickness of 75 μm, and the adhesive layer is laminated to abut against the curling layer. After preparing the laminate, a binder elastic layer formed by thermosetting an acrylate resin on the other surface of the base layer formed on the laminate to a thickness of 30 to 300 μm is formed, and a self-recovering layer is formed on the upper surface of the binder elastic layer. {100 parts by weight of urethane resin, 50 parts by weight of isocyanate, 75 parts by weight of curing agent (benzophenone) and 60 parts by weight of solvent (propylene glycol methyl ether acetate)} are formed to a thickness of 25 μm, and the upper surface of the self-recovery layer is formed. A protective film layer made of self-adhesive polypropylene was formed to a thickness of 40 µm to prepare a liquid crystal protective film with improved surface lift.

<Comparative Example 1>

Proceeding in the same manner as in Example 1, a protective film layer was formed of a silicone adhesive film formed by applying a silicone adhesive to a thickness of 8 μm on one surface of a polyethylene terephthalate having a thickness of 50 μm, and the amount of the silicone adhesive in an amount of 210 g/25 mm. A liquid crystal protective film was prepared by forming an adhesive layer formed by coating with.

<Comparative Example 2>

Proceeding in the same manner as in Example 1, an urethane adhesive was applied in an amount of 1000 g/25 mm to form an adhesive layer to prepare a liquid crystal protective film.

<Comparative Example 3>

The same procedure as in Example 1 was carried out, but an adhesive layer formed by applying a urethane adhesive in an amount of 1500 g/25 mm was formed to prepare a liquid crystal protective film.

After applying the liquid crystal protection film prepared through Examples 1 and 1 to 3 to the mobile phone (Galaxy S9) having a curved surface at the edge portion, it is shown in FIG.

(However, the occurrence of the excitation phenomenon was applied to the liquid crystal protective film prepared through Example 1 and Comparative Examples 1 to 3 to the mobile phone, and a method of photographing the shape of the curvature after 24 hours was used.)

As shown in FIG. 2 below, the liquid crystal protection film manufactured through Example 1 of the present invention did not exhibit an excitation phenomenon in the curved portion, but the liquid crystal protection film manufactured through Comparative Examples 1 to 3 exhibits an excitation phenomenon in the curved portion. Occurred.

Therefore, the disclosed liquid crystal protective film with improved surface lift-off phenomenon is applied to the curved surface of the display to improve the touch feeling by suppressing the lift-up phenomenon, and forms a curl on the side surface without forming by using the shrinkage generated in the radical polymerization reaction. Thus, it provides a liquid crystal protection film that can be applied to the curved portion of a large-angle display.

10; Base layer
20; Binder elastic layer
30; Self-restoration
40; Protective film layer
50; Curl forming layer
60; Adhesive layer

Claims (8)

Base layer;
A binder elastic layer formed on one surface of the base layer;
A self-recovery layer formed on the upper surface of the binder elastic layer;
A protective film layer formed on an upper surface of the self-recovery layer;
A curl forming layer formed on the other surface of the base layer; And
An adhesive layer formed on the lower surface of the curl forming layer; A liquid crystal protection film having improved curved surface lifting.
The method according to claim 1,
The substrate layer is formed of a thickness of 25 to 100㎛, a liquid crystal protection film with improved curved surface lifting, characterized in that consisting of corona or primer-treated polyethylene terephthalate.
The method according to claim 1,
The binder elastic layer is formed to a thickness of 30 to 300㎛, liquid crystal protection with improved surface excitation phenomenon characterized in that it is formed by thermosetting or UV curing a resin containing an acrylate-based, urethane-based and urethane methacrylate-based film.
The method according to claim 1,
The self-recovery layer is formed of a thickness of 10 to 40㎛, the liquid crystal protective film is improved curved surface lifting phenomenon characterized in that it is made of a urethane mixture.
The method according to claim 4,
The urethane mixture is a liquid crystal protective film having improved curved surface lifting, characterized in that consisting of a urethane resin, isocyanate, curing agent and solvent.
The method according to claim 1,
The protective film layer is a self-adhesive, the liquid crystal protective film is improved curved surface lifting phenomenon characterized in that it is made of polypropylene or polyethylene.
The method according to claim 1,
The curl-forming layer is 100% by weight of a photocurable oligomer, 1 to 15 parts by weight of a photocurable monomer and a photopolymerization initiator and/or 1 to 15 parts by weight of a photosensitizer.
The method according to claim 1,
The adhesive layer is formed of a thickness of 50 to 250㎛, a liquid crystal protective film having improved curvature of the curved surface, characterized in that consisting of a transparent adhesive film for curing after ultraviolet light.

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