KR101828826B1 - Film for sublimation transfer including hard-coating layer - Google Patents

Abstract

The sublimation transfer film of the present invention is formed from a hard coating composition comprising a base layer and a photocurable oligomer on one side of the base layer, wherein the content of the polyester (meth) acrylate oligomer in the total solid weight of the photopolymerizable oligomer Is at least 50% by weight. Sublimation transfer applicability is maintained, and a sublimation transfer film improved in abrasion resistance, durability and image formability by a hard coating layer is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a film for sublimation,

The present invention relates to a sublimation-use film comprising a hard coat layer. More particularly, the present invention relates to a sublimation-use film comprising a hard coating layer attached to an adherend and capable of printing by sublimation transfer.

Sublimation transfer is a method for implementing an image on a transfer object (an object to be printed) using sublimation which changes from a solid state to a gaseous state directly. For example, an ink for sublimation is output to a transfer sheet through an inkjet printer, and the output transfer sheet is thermo-compressed to the transfer subject, so that the sublimation transfer ink is infiltrated into the transfer target, Can be implemented.

The sublimation transfer can be applied to a transfer object which is difficult to realize a stable image by a general printing or dyeing method such as cloth, glass, or iron plate. For example, the sublimation transfer film may be imaged on the film before sublimation, and then the sublimation film may be adhered to a billboard such as a glass plate.

When the sublimation film is adhered indoors or outdoors for advertising purposes, it is necessary to secure durability, hardness, light fastness, etc. in addition to excellent sublimation transfer quality.

For example, Korean Patent Registration No. 10-0540727 (Dec. 27, 2005) discloses a sublimation transfer printing method and apparatus thereof, but discloses a method and system for sublimation transfer printing, Is not included.

Korean Patent Registration No. 10-0540727 (December 27, 2005)

An object of the present invention is to provide a sublimation-use film having excellent print quality and durability.

1. A hard coating layer formed from a hard coat composition comprising a substrate layer and a photocurable oligomer on one side of the substrate layer, wherein the content of the polyester (meth) acrylate oligomer in the total weight of solids of the photocurable oligomer Is at least 50% by weight.

2. The film for sublimation as in 1 above, wherein the photo-curable oligomer further comprises a urethane (meth) acrylate oligomer.

3. The photopolymerizable oligomer according to 2 above, wherein the content of the polyester-based (meth) acrylate oligomer is 50 to 90% by weight and the content of the urethane (meth) acrylate oligomer is 10 to 50 % ≪ / RTI >

4. The film for sublimation as in 1 above, wherein the hard coating composition further comprises a photopolymerizable monomer, a photopolymerization initiator, and a solvent.

5. The film for sublimation as in 4 above, wherein the photocurable oligomer is contained in an amount of 20 to 80% by weight in the total weight of the hard coating composition.

6. The film for sublimation as in 1 above, wherein the hard coat layer has a glass transition temperature of 100 ^° C or less and a melting point of 200 ^° C or more.

7. The film for sublimation as in 1 above, further comprising a white ink layer formed on the other surface opposite to the one surface of the base layer.

8. The film for sublimation as in 7 above, wherein the white ink layer is a single layer or a two-layer structure.

9. The film for sublimation as in 1 above, further comprising a pressure-sensitive adhesive layer formed on the bottom surface of the white ink layer, and a release film formed on the bottom surface of the pressure-sensitive adhesive layer.

10. A mobile phone protective case having any one of the above sub-sublimation use films attached thereto.

The sublimation transfer film according to the embodiments of the present invention includes a hard coating layer on the substrate layer, thereby protecting the surface of the sublimation film, and can have excellent durability, light resistance, and hardness. In addition, the surface of the adherend such as the advertisement on which the sublimation-use film is adhered can be protected, and the quality and life of the image realized in the advertisement can be improved.

The sublimation transfer film can be used not only for advertising but also for image decoration for decorating the back surface of a mobile phone or for decorating a surface of a mobile phone case.

1 is a schematic cross-sectional view showing a sublimation transfer film according to an embodiment of the present invention.
2 is a schematic cross-sectional view showing a sublimation transfer film according to an embodiment of the present invention.
3 is a schematic cross-sectional view showing a sublimation transfer film according to an embodiment of the present invention.

Embodiments of the present invention include a substrate layer, a hard coat layer formed on one side of the substrate layer, and a white ink layer formed on the other side opposite to the one side of the substrate layer, And is improved in properties such as durability and light fastness.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings. While the following preferred embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as defined by the following claims. It will be obvious to those skilled in the art that such modifications and variations are within the scope of the appended claims.

≪ Substrate for sublimation including hard coating layer >

Referring to FIG. 1, the sublimation transfer film according to the embodiments of the present invention includes a substrate layer 10, and a hard coating layer 20 formed on the substrate layer 10.

The substrate layer 10 may correspond to a transfer object to which an image is transferred by sublimation transfer. For example, the transfer paper on which the transfer ink is printed may be thermocompression-bonded to the sublimation transfer film, and the transfer ink printed on the transfer paper through the sublimation transfer may penetrate into the substrate layer 10 to transfer the image .

The base layer 10 may comprise a film material including a transparent resin. For example, the substrate layer 10 may be formed of a resin material such as polyethylene terephthalate (PET), polyurethane (PU), polycarbonate (PC), and cellulose acetate . ≪ / RTI >

The hard coating layer 20 may be laminated on one surface (for example, the upper surface of the base layer 10) of the base layer 10. [ The hard coating layer 20 is formed of a material that can be transferred into the base layer 10 by permeation of the transfer ink during the sublimation transfer. In addition, it may be formed of a material having transparency and having appropriate durability and hardness so as to protect the outer surface of the substrate layer 10 on which the image is transferred and ensure resistance to the external environment.

The hard coat layer 20 may be formed by applying a hard coating composition on the substrate layer 10 and then through a curing process (e.g., an ultraviolet curing process). According to exemplary embodiments, the hard coating composition may comprise a photocurable oligomer, a photopolymerizable monomer, a photopolymerization initiator, and a solvent.

The photo-curable oligomer may comprise a polyester-based (meth) acrylate oligomer. The term "(meth) acrylic-" as used herein refers to 'acryl-', 'methacrylic-', or both.

The polyester-based (meth) acrylate can be produced by reacting a polyester polyol and acrylic acid according to a method known in the art. For example, the polyester-based (meth) acrylate may be a polyester acrylate, a polyester diacrylate, a polyester tetraacrylate, a polyester hexaacrylate, a polyester pentaerythritol triacrylate, a polyester pentaerythritol tetra Acrylate or polyester pentaerythritol hexaacrylate, and the like. These may be used alone or in combination of two or more.

In some embodiments, the photocurable oligomer may comprise two or more oligomers. For example, the photocurable oligomer may further include at least one other oligomer besides the polyester-based (meth) acrylate oligomer. In one embodiment, the photocurable oligomer may further comprise a urethane (meth) acrylate oligomer.

The urethane (meth) acrylate oligomer can be prepared, for example, by reacting a polyfunctional (meth) acrylate having a hydroxyl group in a molecule with a compound having an isocyanate group.

The multifunctional (meth) acrylate having a hydroxyl group in the molecule includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl Caprolactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra (meth) acrylate mixture or dipentaerythritol penta / hexa (meth) acrylate, and the like. These may be used alone or in combination of two or more.

Examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 1,5 Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, -Methylenebis (cyclohexylisocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene- Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate Derived trifunctional isocyanate, or trimethane propanol adduct < RTI ID = 0.0 > It can include such sites. These may be used alone or in combination of two or more.

In some embodiments, the content of the polyester-based (meth) acrylate oligomer in the total weight of solids of the photo-curable oligomer may be at least about 50% by weight. When the content of the polyester-based (meth) acrylate oligomer is less than about 50% by weight, the hardness of the hard coat layer 20 and sufficient penetration of the transfer ink may not be ensured during sublimation transfer

In one embodiment, the photocurable oligomer comprises the polyester-based (meth) acrylate oligomer and the urethane (meth) acrylate oligomer, wherein the total weight of solids of the photocurable oligomer, ) Acrylate oligomer may be about 50 to 90% by weight, and the content of the urethane (meth) acrylate oligomer may be about 10 to 50% by weight.

In one embodiment, the photocurable oligomer is substantially comprised of the polyester (meth) acrylate oligomer and the urethane (meth) acrylate oligomer, and does not include oligomers of other families for sublimation transferability .

The photocurable oligomer in the total weight of the hard coating composition may be included in an amount of about 20 to 80% by weight. When the content of the photo-curable oligomer is less than about 20% by weight, sufficient durability and hardness of the film for sublimation may not be ensured. When the content of the photo-curable oligomer is more than about 80% by weight, sufficient penetration of the transfer ink may not be ensured when sublimation transfer is carried out.

The photopolymerizable monomer can be used without any particular limitation as far as it is a compound capable of photopolymerization and capable of forming a transparent resin film. For example, the photopolymerizable monomer may be a compound containing at least one of (meth) acryloyl group, vinyl group, styryl group or allyl group.

Preferably, the photopolymerizable monomer may be a monomer having a (meth) acryloyl group. Examples of the monomer having a (meth) acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di Acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethane tri (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol hexa (metha) acrylate, bis (2-hydroxyethyl) isocyanurate di (Meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobutyl (meth) acrylate, , Phenoxyethyl (meth) acrylate, isobonol (meth) acrylate, and the like, but are not limited thereto.

The content of the photopolymerizable monomer is not particularly limited, but may be in the range of about 5 to 20% by weight based on the total weight of the hard coating composition.

The photopolymerization initiator used in the technical field can be used without any particular limitation. For example, the photopolymerization initiator may be selected from the group consisting of benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chronoloacetophenone, 4,4-dimethoxy Methyl-1-phenyl-1-one, 1-hydroxycyclohexyl phenyl ketone, 4-hydroxycyclohexyl phenyl ketone, Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl- 2- 2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methyl anthraquinone, 2 - ethyl anthraquinone, 2-t-butyl anthraquinone, 2-methylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone], 2,4 , 6-trimethylbenzoyldiphenylphosphine oxide, fluorene, triphenylamine, carbazole, and the like. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, but may be in the range of about 0.1 to 5% by weight based on the total weight of the hard coating composition.

Any agent known in the art capable of dissolving or dispersing the above-mentioned components as the solvent can be used without any particular limitation. Examples of the solvent include alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol and the like), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, ), Ethers (propylene glycol monomethyl ether, etc.), acetate (methyl acetate, ethyl acetate, butyl acetate, propylene glycol methoxy acetate and the like), cellosolve type (methyl cellosolve, ethyl cellosolve, , Hydrocarbons (normal hexane, normal heptane, benzene, toluene, xylene, etc.) can be used. These may be used alone or in combination of two or more.

The content of the solvent is not particularly limited, but may be included in an amount of about 10 to 50% by weight based on the total weight of the hard coating composition.

In order to improve the physical properties (e.g., abrasion resistance, scratch resistance, pencil hardness, etc.) of the hard coat layer 20 or the coatability of the hard coat composition, an additive may be further included in the hard coat composition. Examples of the additives include leveling agents, inorganic particles, ultraviolet absorbers, and light stabilizers.

The hard coating layer 20 is formed by applying and hardening the above-mentioned hard coating composition on the base layer 10 and may be formed by a slit coating method, a knife coating method, a spin coating method, a casting method, a microgravure coating method, There can be used various coating methods such as coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, gravure printing method, flexo printing method, offset printing method, ink jet coating method, A coating method, a capillary coating method, and the like can be used.

According to exemplary embodiments, the glass transition temperature (Tg) and melting point (Tm) of the hard coat layer 20 can be adjusted in consideration of the sublimation transfer temperature. For example, the sublimation transfer temperature may range from about 100 to 250 ^° C, preferably from 130 to 200 ^° C. In this case, the glass transition temperature of the hard coat layer 20 may be controlled to be 100 ^° C or less and the melting point may be 200 ^° C or more. The content of the photocurable oligomer and the content of the polyester-based (meth) acrylate oligomer in the photocurable oligomer may be adjusted as described above in consideration of the glass transition temperature and melting point of the hard coat layer 20.

The thickness of the hard coat layer 20 can be set in consideration of mechanical properties such as durability, abrasion resistance and hardness of the hard coat layer 20, and sublimation transfer applicability. In one embodiment, the thickness of the hard coat layer 20 can be about 1 to 30 microns, and preferably about 10 to 30 microns.

In one embodiment, the thickness ratio of the hard coat layer 20 to the substrate layer 10 can be set in the range of about 0.5 to 2. When the thickness ratio is less than about 0.5, the above-mentioned mechanical properties may be deteriorated. On the other hand, if the thickness ratio exceeds about 2, the possibility of sublimation transfer may be reduced.

In one embodiment, the pencil hardness of the hard coat layer 20 may be at least 2H to provide abrasion resistance and scratch resistance.

Referring to FIG. 2, the sublimation transfer film according to the embodiments of the present invention may further include a white ink layer 30. According to exemplary embodiments, the white ink layer 30 is deposited on the other side (e.g., the bottom of the substrate layer 10) opposite the one side of the substrate layer 10 in which the hard coat layer 20 is laminated . The sublimation ink may not contain white so that a white ink layer 30 may be additionally formed on the other side of the substrate layer 10 for white implementation.

In some embodiments, the white ink layer 30 may be formed as a single layer structure or a two layer structure. For example, the white ink layer 30 can be formed through a single application of a white ink or two application processes. By limiting the number of layers of the white ink layer 30 to two or less, the number of interfaces in the white ink layer 30 can be reduced to prevent a decrease in optical characteristics due to a change in the refractive index or the like.

Referring to FIG. 3, the sublimation transfer film according to the embodiments of the present invention may further include an adhesive layer 40 and a release film 50.

The adhesive layer 40 may be formed to impart adhesion between the sublimation transfer film and adherend such as a billboard. The adhesive layer 40 may be provided as a transparent adhesive layer or a white adhesive layer.

The adhesive layer 40 can be formed, for example, by applying a pressure-sensitive adhesive composition containing an acrylic copolymer and a solvent to the bottom surface of the white ink layer 30 and then curing the adhesive composition. For example, the acrylic copolymer may be formed from a mixture of monomers comprising at least one acrylate-based compound and acrylic acid. Examples of the acrylate-based compound include 2-ethylhexyl acrylate, butyl acrylate, vinyl acrylate, and cyclohexylmethyl acrylate. The pressure-sensitive adhesive composition may include a silicone-based pressure-sensitive adhesive.

When the adhesive layer 40 is provided as the white adhesive layer, a white pigment such as titanium oxide may be further added to the adhesive composition.

The release film 50 is attached for protection of the adhesive layer 40 and can be removed before it is applied to the adherend. As the release film 50, for example, a silicon-based or polyethylene-based resin film or a paper-made film can be used.

As described above, according to the embodiments of the present invention, the sublimation transfer applicability is retained on the base layer 10 included in the sublimation film, and the hard coating layer (for the sublimation transfer application) for abrasion resistance, scratch resistance, 20 may be formed. Therefore, it is possible to protect the surface of the transferred image and to preserve the desired quality image for a long time.

The sublimation film according to embodiments of the present invention can be applied to a cellular phone and a cellular phone case.

In some embodiments, the sublimation transfer film onto which an image has been transferred by the sublimation transfer process can be applied to, for example, a back surface (e.g., a battery cover) of the cellular phone. For example, as shown in FIG. 3, the release film 50 may be removed, and the adhesive layer 40 may be attached to the back surface to be used as a decorative article of a mobile phone.

In some embodiments, the sublimation transfer film onto which an image has been transferred by the sublimation transfer process can be applied to, for example, a mobile phone case for mobile phone protection. For example, as shown in FIG. 3, the release film 50 may be removed and the adhesive layer 40 may be attached to the inner plane or the outer plane of the cell phone case, so that the cell phone can be used as a cellular phone decorating device at the same time as the cell phone protecting performance .

Hereinafter, the characteristics of the sublimation-use film including the hard coating layer according to the embodiments of the present invention will be described in more detail through specific experimental examples. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments within the scope and spirit of the present invention, It is obvious that such variations and modifications are included in the appended claims.

Preparation Example 1: Preparation of hard coating composition (Example 1)

A photo-curable oligomer was prepared by mixing 50 wt% of polyester acrylate as a polyester (meth) acrylate oligomer and 50 wt% of SC2100 as a urethane (meth) acrylate oligomer. The hard coat composition of Preparation Example 1 was prepared by mixing 40 wt% of the photo-curable oligomer, 10 wt% of pentaerythritol tri (meth) acrylate, 5 wt% of benzoin and 45 wt% of isopropanol.

Preparation Example 2: Preparation of hard coating composition (Example 2)

The hard coat composition of Production Example 2 was prepared in the same manner as in Production Example 1, except that 100 wt% of polyester acrylate was used as the photo-curable oligomer.

Preparation Example 3: Preparation of hard coating composition (Comparative Example 1)

The hard coat composition of Production Example 3 was prepared in the same manner as in Production Example 1, except that the weight% of the polyester acrylate was 30 wt% (urethane (meth) acrylate oligomer 70 wt%).

Preparation Example 4: Preparation of hard coating composition (Comparative Example 2)

The hard coat composition of Production Example 4 was prepared in the same manner as in Production Example 1, except that 100 wt% of the urethane (meth) acrylate oligomer was used as the photo-curable oligomer.

Examples and Comparative Examples

The hard coating composition of Preparation Example 1 and Preparation Example 2 was applied to a PET base layer having a thickness of 10 占 퐉 and hardened to form a hard coat layer having a thickness of 10 占 퐉 to prepare the sublimation used films of Examples 1 and 2, Respectively.

The hard coating compositions of Production Example 3 and Production Example 4 were applied and cured as described above to form hard coating layers to prepare the sublimation films of Comparative Examples 1 and 2, respectively.

Experimental Example

The surface hardness (pencil hardness) and the color coordinate difference (DELTA E) of the films used before sublimation in Examples 1, 2, and 1 and Comparative Example 2 were measured and the measurement results are shown in Table 1 below .

Specifically, the surface hardness was measured by a surface pencil hardness test method using the ASTM D3363-00 standard. The color coordinate difference is a numerical value indicating the difference in distance between different colors in the color space coordinates. For example, if ΔE is less than 0.5, it is recognized as the same color, and if it is about 1.0, it may not be visually distinguished. That is, as ΔE is larger, the color difference becomes larger and can be distinguished visually.

In this experimental example, a sublimation transfer sheet printing a circular image of four colors of black, yellow, red, and blue is prepared, and a sublimation transfer sheet before transfer is transferred to a reference E was measured with the color remaining after the sublimation transfer paper. The larger ΔE indicates that the ink on the sublimation transfer paper was transferred to the sublimation transfer film. "Node + chromaPro" of Variable INC. Was used as the analysis equipment, and the results were recorded using the mean and standard deviation of five measurements.

The images transferred to the sublimation transfer films according to Examples and Comparative Examples were visually compared with each other to evaluate the image transfer state. More specifically, the sharpness was visually evaluated based on the image transferred to the sublimation transfer fabric (fabric) used in common.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Surface hardness 2H 2H 2H 1H ΔE Black 36.9 ± 1.1 25.9 ± 1.0 11.1 ± 0.7 10.0 + - 0.4 Yellow 11.5 ± 0.3 8.5 ± 0.2 4.4 ± 2.3 3.3 ± 0.4 Red 31.2 ± 1.0 23.2 ± 1.1 9.8 ± 0.8 8.0 ± 0.5 Blue 26.8 ± 0.8 18.8 ± 0.8 12.1 ± 0.4 10.0 ± 0.6 Image transfer status ○ ○ X X

Referring to Table 1, a large ΔE value was exhibited in the examples formed using the photo-curable oligomer containing 50% by weight or more of the polyester acrylate oligomer in comparison with the comparative examples, Images or colors on the sublimation transfer film were more clearly implemented. In particular, in the case of Comparative Example 2 in which the urethane (meth) acrylate oligomer was 100%, the surface hardness was measured to be less than 2H.

On the other hand, in the case of Example 2 in which the urethane (meth) acrylate oligomer was excluded and 100 wt% of the polyester acrylate was used, the DELTA E value was somewhat reduced as compared with Example 1, but significantly higher DELTA E and image transfer The state was obtained.

10: base layer 20: hard coat layer
30: white ink layer 40: adhesive layer
50: release film

Claims (12)

A substrate layer provided as a transfer object onto which an image is transferred by a sublimation transfer; And
A hard coat layer formed on the one surface of the base layer, the hard coat layer being formed from a hard coat composition comprising a photocurable oligomer and permeating the sublimed transfer ink,
Wherein the content of the polyester-based (meth) acrylate oligomer in the total weight of solids of the photocurable oligomer is 50% by weight or more. The sublimation film of claim 1, wherein the photo-curable oligomer further comprises a urethane (meth) acrylate oligomer. (Meth) acrylate oligomer is contained in an amount of 50 to 90% by weight, the content of the urethane (meth) acrylate oligomer is 10 to 50% by weight, and the content of the urethane (meth) acrylate oligomer in the total solid weight of the photo- In, a film used before sublimation. The sublimation-use film according to claim 1, wherein the hard coating composition further comprises a photopolymerizable monomer, a photopolymerization initiator, and a solvent. 5. The film for sublimation as claimed in claim 4, wherein the photocurable oligomer is contained in an amount of 20 to 80% by weight in the total weight of the hard coating composition. The sublimation-use film according to claim 1, wherein the hard coating layer has a glass transition temperature of 100 ^° C or lower and a melting point of 200 ^° C or higher. The sublimation film according to claim 1, further comprising a white ink layer formed on the other surface opposite to the one surface of the base layer. 8. The film for sublimation as claimed in claim 7, wherein the white ink layer has a single layer or a two-layer structure. The film for sublimation as claimed in claim 7, further comprising an adhesive layer formed on the bottom surface of the white ink layer, and a release film formed on the bottom surface of the adhesive layer. A cell phone protective case with the sublimation film of any one of claims 1 to 9 attached thereto. Preparing a substrate layer;
Forming a hard coating layer from a hard coating composition comprising a photo-curable oligomer on one side of the substrate layer to produce a film for sublimation;
Pressing the transfer paper onto which the transfer ink is printed onto the hard coat layer; And
Transferring the transfer ink through the hard coat layer through a sublimation transfer to transfer an image to the substrate layer. 12. The sublimation transfer method according to claim 11, wherein the hard coat layer remains on the base layer after the sublimation transfer to protect the base layer.

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