JP7168348B2 - Graphic film for license plate, graphic film laminated plate, license plate and manufacturing method thereof - Google Patents

Description

The present disclosure relates to graphic films for license plates, graphic film laminate plates, license plates and methods of making the same.

A decorated license plate (also referred to as a “license plate”; the same shall apply hereinafter in the present disclosure) is used. Decoration is performed by painting the baseplate, printing on the baseplate, or attaching a graphic film to the baseplate. Decorations using graphic films are expected to become more popular as license plate decorations because of their high designability and environmental friendliness during production.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2016-215672) describes "a graphic film for a license plate, comprising a base film layer having an upper surface and a lower surface, and a pressure-sensitive adhesive layer disposed on the lower surface of the base film layer. , the pressure-sensitive adhesive layer comprises (a) a carboxyl group-containing adhesive (meth)acrylic polymer having a glass transition temperature of −50° C. or lower, and (b) an amino group containing no monomer unit derived from an aromatic vinyl monomer. a dispersant containing a (meth)acrylic polymer; at least one tackifier selected from the group consisting of terpene resins; ) a graphic film containing 10 parts by mass or more of a white pigment with respect to a total of 100 parts by mass of a dispersant and a tackifier containing an acrylic polymer.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2017-177481) describes "a graphic film for license plates, comprising a polyurethane surface protective layer to which a printing layer is applied, wherein the polyurethane surface protective layer comprises at least a polyester skeleton or a polycarbonate skeleton. and a polyfunctional aliphatic isocyanate reaction product, or a water-based polyurethane.

JP 2016-215672 A JP 2017-177481 A

A graphic film for a license plate using a polyvinyl chloride (hereinafter also referred to as "PVC" in the present disclosure) film is known. On the other hand, a non-PVC-based graphic film for a license plate containing no PVC is desired by some applications or consumers. However, the non-PVC film may not follow the embossed portion of the license plate as well as the PVC film, which has excellent workability. And there was a tendency for the graphic film to break at the portion where it was stretched by the projections. On the other hand, PVC film has low impact resistance at low temperatures. For example, when the ambient temperature drops below freezing or even -20°C in winter, when a pebble or the like hits the license plate, the graphic film will be perforated or cracked. I was afraid.

The present disclosure provides a non-PVC-based graphic film for license plates that has excellent conformability to embossed portions and excellent impact resistance at low temperatures.

According to one embodiment of the present disclosure, a non-PVC graphic film for license plates comprising (A) an overlaminate film and (B) an image-bearing film, wherein the overlaminate film comprises (a1) a non-yellowing comprising a transparent polyurethane layer and (a2) a transparent adhesive layer, said image carrying film comprising (b1) a graphic image layer, (b2) a non-yellowing polyurethane image-receiving layer, and (b3) a white adhesive layer, said overlaminate A film is laminated to the image-bearing film via the transparent adhesive layer so as to cover at least a portion of the graphic image layer, and the total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer is is less than the combined thickness of the transparent adhesive layer and the white adhesive layer.

According to another embodiment of the present disclosure, there is provided a graphic film laminate plate including the above graphic film and a base plate.

According to yet another embodiment of the present disclosure, there is provided a license plate including the graphic film described above and a base plate.

According to yet another embodiment of the present disclosure, providing a base plate; applying the graphic film on or above the base plate to form a graphic film laminate plate; and applying a printing layer to the embossed or debossed graphic film laminate plate in the raised or recessed areas.

The non-PVC-based graphic film for license plates of the present disclosure is excellent in conformability to embossed portions and impact resistance at low temperatures such as 0°C to -20°C.

The above description should not be considered to disclose all embodiments of the invention or all advantages associated with the invention.

1 is a schematic cross-sectional view of a non-PVC-based graphic film for license plates according to one embodiment of the present disclosure; FIG. FIG. 2 shows cross-sectional views of a procedure for manufacturing a license plate according to an embodiment of the present disclosure. FIG. FIG. 2 shows cross-sectional views of a procedure for manufacturing a license plate according to an embodiment of the present disclosure. FIG. FIG. 2 shows cross-sectional views of a procedure for manufacturing a license plate according to an embodiment of the present disclosure. FIG. FIG. 2 shows cross-sectional views of a procedure for manufacturing a license plate according to an embodiment of the present disclosure. FIG. FIG. 2 shows cross-sectional views of a procedure for manufacturing a license plate according to an embodiment of the present disclosure. FIG.

Hereinafter, the present invention will be described in more detail with reference to the drawings for the purpose of illustrating representative embodiments of the invention, but the invention is not limited to these embodiments. With respect to drawing reference numbers, like-numbered elements in different drawings indicate similar or corresponding elements.

In this disclosure, "non-PVC-based" means that the graphic film is substantially free of polyvinyl chloride, such as polyvinyl chloride film or polyvinyl chloride layer. In some embodiments, the graphic film has a polyvinyl chloride content of about 1 wt% or less, about 0.5 wt% or less, or about 0.1 wt% or less.

In the present disclosure, "non-yellowing polyurethane" refers to polyurethanes that do not undergo substantial discoloration when exposed to outdoor vertical surfaces for at least 5 years or more. "No substantial color change occurs" means that the color difference ΔE ^* ab when the chromaticity of the non-yellowing polyurethane is measured in the L ^* a ^* b ^* color system of CIE (International Commission on Illumination) 1976 is about 5 or less, preferably about 4 or less, more preferably about 3 or less.

In the present disclosure, "film" also includes an article called "sheet".

In the present disclosure, "(meth)acrylic" means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate.

In the present disclosure, "pressure-sensitive adhesive" means that it is permanently tacky in the temperature range of use, e.g. solid) means the property of a material or composition that does not exhibit

In the present disclosure, "transparent" means that a certain material or article has a total light transmittance of about 85% or more in the wavelength range of 400 to 700 nm, and "translucent" means that a certain material or article has a wavelength range It means that the total light transmittance at 400-700 nm is about 20% or more and less than about 85%, and "opaque" means that a material or article has a total light transmittance of about 20% in the wavelength range of 400-700 nm. means less than Total light transmittance is determined according to JIS K 7361-1:1997 (ISO 13468-1:1996).

A graphic film for a license plate of one embodiment (hereinafter sometimes simply referred to as "graphic film") includes (A) an overlaminate film and (B) an image-bearing film, and is non-PVC-based. The overlaminate film comprises (a1) a non-yellowing transparent polyurethane layer and (a2) a transparent adhesive layer. The image-bearing film comprises (b1) a graphic image layer, (b2) a non-yellowing polyurethane image-receiving layer, and (b3) a white adhesive layer. The overlaminate film is adhered to the image carrier film via a transparent adhesive layer so as to cover at least a portion of the graphic image layer. The total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer is less than the total thickness of the transparent adhesive layer and white adhesive layer. By setting the thickness relationships of the constituent elements of the graphic film as described above, a graphic film that is non-PVC but has good conformability to embossed parts and exhibits excellent impact resistance at low temperatures is provided. can do.

FIG. 1 shows a schematic cross-sectional view of a non-PVC-based graphic film 10 for license plates according to one embodiment. The graphic film 10 includes (A) an overlaminate film 20 and (B) an image-bearing film 30 . The overlaminate film 20 includes (a1) a non-yellowing transparent polyurethane layer 22 and (a2) a transparent adhesive layer 24 . The image bearing film 30 includes (b1) a graphic image layer 32, (b2) a non-yellowing polyurethane image-receiving layer 34, and (b3) a white adhesive layer . The overlaminate film 20 is laminated to the image carrier film 30 via the transparent adhesive layer 24 so as to cover the graphic image layer 32 .

As shown in FIG. 1, the non-yellowing transparent polyurethane layer 22 and the transparent adhesive layer 24 may be directly adhered or may be adhered via a bonding layer. The non-yellowing transparent polyurethane layer 22 may have a surface treatment such as primer treatment or corona treatment on the surface to be adhered to the transparent adhesive layer 24 .

As shown in FIG. 1, the non-yellowing polyurethane image-receiving layer 34 and the white adhesive layer 36 may be directly adhered or may be adhered via a bonding layer. The non-yellowing polyurethane image-receiving layer 34 may have a surface treatment such as primer treatment or corona treatment on the surface to be adhered to the white adhesive layer 36 .

The non-yellowing transparent polyurethane layer imparts excellent weatherability, chemical resistance and impact resistance to the graphic film. In one embodiment, the non-yellowing transparent polyurethane layer also functions as an ink-receiving layer, and pigments and binders such as melamine resins, alkyd resins, urethane resins, and mixed resins thereof are placed on the non-yellowing transparent polyurethane layer. The ink composition containing the compound can also be used to form a printed layer that constitutes a display portion for numbers, characters, and the like.

Various polyurethane resins can be used for the non-yellowing transparent polyurethane layer. In one embodiment, the non-yellowing transparent polyurethane layer comprises a polyurethane resin that is a polycondensate of polyol and polyisocyanate. A reactive polyurethane composition containing a polyol and a polyisocyanate, or a polyurethane resin composition containing a polyurethane resin and an organic solvent or water is coated, for example, by knife coating, bar coating, blade coating, doctor coating, roll coating, cast coating, etc. A non-yellowing transparent polyurethane layer can be formed by applying it to the liner and heating or drying as necessary. In the reactive polyurethane composition, the polyol and the polyisocyanate react with each other during heating or drying to form a polyurethane resin. A non-yellowing transparent polyurethane layer may be formed by a casting method using a reactive polyurethane composition or a polyurethane resin composition.

Polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4 - low-molecular-weight polyols having 2 to 20 carbon atoms such as butanediol, 1,6-hexanediol, glycerin; methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene glycol ( A (meth)acrylic that is a copolymer of a hydroxyl-free (meth)acrylate such as a meth)acrylate diester and a hydroxyl-containing (meth)acrylate such as 2-hydroxyethyl (meth)acrylate or ethylene glycol methacrylic acid monoester. Polyols; Polyurethane polyols; Polyester polyols such as polycaprolactone diol and polycaprolactone triol; Polycarbonate polyols such as cyclohexanedimethanol carbonate and 1,6-hexanediol carbonate; propylene oxide adducts of glycerin, propylene oxide adducts of sugars such as sorbitol and sucrose, and polyether polyols such as propylene oxide adducts of compounds having active hydrogen such as ethylenediamine. Polyols are generally aliphatic or cycloaliphatic compounds.

Aliphatic polyisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate as polyisocyanate; isophorone diisocyanate, trans and/or cis-1, Alicyclic polyisocyanates such as 4-cyclohexane diisocyanate, norbornene diisocyanate, hydrogenated diphenylmethane diisocyanate, and non-yellowing polyisocyanates such as burettes, isocyanurates and adducts thereof can be used. The polyisocyanate may be a blocked isocyanate blocked with a blocking agent.

The equivalent ratio of polyisocyanate to polyol is generally about 0.7 equivalents or more, about 0.9 equivalents or more, about 2 equivalents or less, or about 1.2 equivalents or less of polyisocyanate to 1 equivalent of polyol. .

The reactive polyurethane composition may contain a catalyst. Catalysts commonly used in polyurethane resin formation, such as di-n-butyltin dilaurate, zinc naphthenate, zinc octenoate, triethylenediamine and the like can be used. The amount of the catalyst used is generally about 0.005 parts by weight or more, or about 0.01 parts by weight or more, and about 0.5 parts by weight or less, or about 0.2 parts by weight or less based on 100 parts by weight of the composition. .

For the purpose of improving workability and coatability, the reactive polyurethane composition and the polyurethane resin composition are prepared by using ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetylacetone, aromatic hydrocarbons such as toluene and xylene, ethanol and isopropyl alcohol. alcohols such as ethyl acetate, esters such as butyl acetate, and ethers such as tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate. The amount of the organic solvent used is generally about 1 part by mass or more, or about 5 parts by mass or more, and about 90 parts by mass or less, or about 80 parts by mass or less based on 100 parts by mass of the composition.

The polyurethane resin composition may be an aqueous polyurethane resin composition containing water as a solvent. The polyurethane resin contained in the aqueous polyurethane resin composition may have chain extender components such as diamines, anionic groups such as carboxyl groups and sulfonic acid groups, and the like.

In one embodiment, the non-yellowing transparent polyurethane layer comprises at least one polyol selected from the group consisting of (meth)acrylic polyols, polyurethane polyols and polycarbonate polyols, particularly (meth)acrylic polyols, and a non-yellowing polyisocyanate. It contains a cured product of a reactive polyurethane composition containing and. According to this embodiment, a graphic film having excellent solvent resistance and weather resistance can be obtained.

The glass transition temperature Tg of the non-yellowing transparent polyurethane layer may be about 50° C. or higher, or about 60° C. or higher, about 100° C. or lower, or about 80° C. or lower. Tg in the present disclosure is the loss tangent tan δ (loss elastic modulus E "/storage modulus E') peak temperature. The non-yellowing transparent polyurethane layer having the above glass transition temperature can impart excellent weather resistance and chemical resistance to the graphic film.

The loss tangent tan δ at 120° C. of the non-yellowing transparent polyurethane layer may be about 0.1 or less, or about 0.05 or less. The loss tangent tan δ in the present disclosure is a value obtained by performing viscoelasticity measurements in shear mode at a frequency of 0.01 Hz. The non-yellowing transparent polyurethane layer having the above loss tangent can impart excellent weather resistance and chemical resistance to the graphic film.

The non-yellowing transparent polyurethane layer may contain other optional additives such as UV absorbers, light stabilizers, heat stabilizers, dispersants, plasticizers, flow improvers and leveling agents.

The thickness of the non-yellowing transparent polyurethane layer is generally about 3 μm or greater, about 5 μm or greater, or about 10 μm or greater. By setting the thickness of the non-yellowing transparent polyurethane layer within the above range, it is possible to impart weather resistance and chemical resistance to the graphic film. The thickness of the non-yellowing transparent polyurethane layer is generally no greater than about 50 microns, no greater than about 30 microns, or no greater than about 20 microns. By setting the thickness of the non-yellowing transparent polyurethane layer within the above range, the conformability to the embossed portion of the graphic film and the impact resistance at low temperatures can be improved.

Weather resistance, solvent resistance, chemical resistance, ink adhesion, etc. can be improved by providing a transparent layer on the non-yellowing transparent polyurethane layer. The thickness of the transparent layer is generally greater than or equal to about 1 μm, greater than or equal to about 2 μm, or greater than or equal to about 3 μm, less than or equal to about 20 μm, less than or equal to about 10 μm, or less than or equal to about 5 μm.

Adhesives that can be used for the transparent adhesive layer include, but are not limited to, (meth)acrylic polymers, natural rubbers, butyl rubbers, isobutyl rubbers, synthetic rubbers such as SBR, polyesters, polyethers, and silicones. , a tacky polymer such as polyurethane or a heat-sensitive adhesive polymer, and optionally additives such as tackifiers, antioxidants, UV absorbers, fillers, plasticizers, etc. can be used. The adhesive may be thermally crosslinked or radiation (eg, electron beam or ultraviolet) crosslinked by means of a crosslinking agent.

The thickness of the transparent adhesive layer can vary and can generally be greater than or equal to about 3 μm, greater than or equal to about 5 μm, or greater than or equal to about 10 μm, less than or equal to about 50 μm, less than or equal to about 30 μm, or less than or equal to about 20 μm. This makes it possible to improve the conformability to the embossed portion of the graphic film and the impact resistance at low temperatures.

The graphic image layer can be used to impart decorative or design qualities to the graphic film. When a graphic film including a graphic image layer is used for a license plate, it is possible to add a picture, pattern, etc. to the background portion of the license plate other than numbers and characters. Examples of graphic image layers include color layers exhibiting special hues, metallic colors, etc., and pattern layers such as wood grain, stone grain, logos, and designs. As a material for the graphic image layer, for example, an ink composition in which a pigment such as an inorganic pigment, an organic pigment, or a luster material is dispersed in a polyvinyl chloride/polyvinyl acetate mixture or a binder containing an acrylic resin can be used. can. In some embodiments, the graphic image layer can be formed using inkjet printing, screen printing, offset printing, electrostatic printing, gravure printing, and the like.

In one embodiment, the graphic image layer is an inkjet printing layer that can be formed using an inkjet printing ink composition.

The thickness of the graphic image layer may vary, and may generally be about 1 μm or more, or about 2 μm or more, about 8 μm or less, or about 5 μm or less when solvent-based inks are used. When UV curable ink is used, the thickness can be about 1 μm or more, or about 5 μm or more, about 30 μm or less, or about 20 μm or less.

The non-yellowing polyurethane image-receiving layer receives the ink composition and carries the graphic image layer. The non-yellowing polyurethane image-receiving layer can also function as a support for graphic films. The non-yellowing polyurethane image-receiving layer may contain the polyurethane resins exemplified for the non-yellowing transparent polyurethane layer, and may be formed using the same reactive polyurethane composition or polyurethane resin composition.

In one embodiment, the non-yellowing polyurethane image-receiving layer comprises a polyether-based polyurethane. A non-yellowing polyurethane image-receiving layer comprising a polyether-based polyurethane is suitable for receiving ink compositions, particularly ink compositions for ink jet printing. A polyether-based polyurethane can be formed, for example, by using a polyether polyol as the polyol. The polyether-based polyurethane is advantageously an aliphatic polyether-based polyurethane in terms of non-yellowing.

In one embodiment, the non-yellowing polyurethane image-receiving layer further comprises an acrylic polyurethane in addition to the polyether-based polyurethane. In this embodiment, the weather resistance of the graphic film can be further enhanced. The blending ratio of the polyether-based polyurethane and the acrylic polyurethane can be 70:30 to 97:3 or 80:20 to 95:5 in solid content mass ratio. The acrylic polyurethane is advantageously an aliphatic acrylic polyurethane in terms of non-yellowing.

In one embodiment, the non-yellowing polyurethane image-receiving layer further comprises a polyester-based polyurethane in addition to the polyether-based polyurethane. In this embodiment, the oil resistance of the graphic film can be further enhanced. The blending ratio of the polyether-based polyurethane and the polyester-based polyurethane can be 70:30 to 97:3 or 80:20 to 95:5 in solid content mass ratio. It is advantageous that the polyester-based polyurethane is an aliphatic polyester-based polyurethane in terms of non-yellowing.

The non-yellowing polyurethane image-receiving layer may be pigmented white or another color, and may be transparent. In one embodiment the non-yellowing polyurethane image-receiving layer is transparent. In this embodiment, when a portion of the ink composition permeates the non-yellowing polyurethane image-receiving layer, the permeated portion can be visually recognized without changing the chroma. Even when used to form a thin graphic image layer, it is possible to provide a graphic film having graphic images that exhibit high definition over a wide range of angles.

The non-yellowing polyurethane image-receiving layer may contain other optional additives such as UV absorbers, light stabilizers, heat stabilizers, dispersants, plasticizers, flow improvers and leveling agents.

The thickness of the non-yellowing polyurethane image-receiving layer is generally about 5 μm or greater, about 10 μm or greater, or about 15 μm or greater. By setting the thickness of the non-yellowing polyurethane image-receiving layer within the above range, sufficient strength can be imparted to the graphic film. The thickness of the non-yellowing polyurethane image-receiving layer is generally no greater than about 50 microns, no greater than about 40 microns, or no greater than about 30 microns. By setting the thickness of the non-yellowing polyurethane image-receiving layer within the above range, the ink composition is reliably received, the clarity of the graphic image layer is ensured, and the followability to the embossed portion of the graphic film and low-temperature performance are ensured. Good impact resistance can be achieved.

In one embodiment, the total thickness of the non-yellowing transparent polyurethane layer of the overlaminate film and the non-yellowing polyurethane image-receiving layer of the image-bearing film is about 80 μm or less, about 70 μm or less, or about 60 μm or less. As a result, the followability of the graphic film to the embossed portion can be further enhanced.

The white adhesive layer hides the color of the underlying baseplate to which the graphic film is applied. The white adhesive layer can be formed using a white adhesive or a white pressure-sensitive adhesive obtained by mixing the same adhesive or pressure-sensitive adhesive as the transparent adhesive layer with a white pigment.

White pigments include, for example, zinc carbonate, zinc oxide, zinc sulfide, and titanium dioxide (titanium oxide). Titanium dioxide can be used particularly advantageously due to its high whiteness and excellent dispersibility. The white pigment may be particles of various shapes such as spherical, needle-like, tabular or flake-like, and spherical particles are preferred because of their good dispersibility. The white pigment may be surface-treated with a coupling agent such as silane or titanate in order to further enhance dispersibility. A polymeric dispersant such as an amino-modified acrylic polymer may be used to enhance the dispersibility of the white pigment.

The average primary particle size of the white pigment may be about 0.10 μm or more, about 0.12 μm or more, or about 0.15 μm or more, about 0.50 μm or less, about 0.40 μm or less, or about 0.30 μm or less. . By setting the average primary particle size of the white pigment within the above range, the white pigment can be more uniformly dispersed in the adhesive. The average primary particle size of the white pigment is the volume cumulative particle size _D50 which can be determined using laser diffraction/scattering particle size distribution.

The thickness of the white adhesive layer can vary and can generally be greater than or equal to about 10 μm, greater than or equal to about 15 μm, or greater than or equal to about 20 μm, less than or equal to about 100 μm, less than or equal to about 80 μm, or less than or equal to about 70 μm. By setting the thickness of the white adhesive layer to about 30 μm or more, or about 50 μm or more, the concealability of the white adhesive layer can be further enhanced, and a license plate can be provided in which a clear graphic image can be visually recognized. In one embodiment, the thickness of the white adhesive layer is greater than the thickness of the non-yellowing polyurethane image-receiving layer. This makes it possible to improve the conformability to the embossed portion of the graphic film and the impact resistance at low temperatures. Pigments such as aluminum flakes, carbon black, and phthalocyanine may be added to the white adhesive layer to improve the hiding power of the white adhesive layer and/or adjust the hue.

In the graphic film of the present disclosure, the total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer is less than the total thickness of the transparent adhesive layer and white adhesive layer. By making the total thickness of the relatively rigid and brittle polyurethane layer smaller than the total thickness of the adhesive layer, both the conformability to the embossed portion of the graphic film and the impact resistance at low temperatures can be enhanced. Ratio of total thickness of non-yellowing transparent polyurethane layer and non-yellowing polyurethane image-receiving layer to total thickness of transparent adhesive layer and white adhesive layer (total thickness of non-yellowing transparent polyurethane layer and non-yellowing polyurethane image-receiving layer/transparent The total thickness of the adhesive layer and the white adhesive layer) is less than 1, preferably about 0.7 or less, more preferably about 0.5 or less.

Ratio of total thickness of non-yellowing transparent polyurethane layer and non-yellowing polyurethane image-receiving layer to total thickness of transparent adhesive layer and white adhesive layer (total thickness of non-yellowing transparent polyurethane layer and non-yellowing polyurethane image-receiving layer/transparent The total thickness of the adhesive layer and the white adhesive layer) is generally about 0.15 or greater, about 0.2 or greater, or about 0.3 or greater. This makes it possible to impart sufficient strength to the graphic film.

The graphic film may have a retroreflective layer between the non-yellowing polyurethane image-receiving layer and the white adhesive layer of the image-bearing film. In this embodiment, the transparency of the non-yellowing polyurethane image-receiving layer is advantageous for the retroreflective performance of the retroreflective layer. The retroreflective layer can include beads or cube-corner elements configured to reflect incident light back toward the light emitting source.

The thickness of the retroreflective layer can vary and can generally be greater than or equal to about 40 microns, or greater than or equal to about 50 microns, or less than or equal to about 100 microns, or less than or equal to about 60 microns.

The retroreflective layer and the non-yellowing polyurethane image-receiving layer may be adhered via a transparent bonding layer. The transparent bonding layer can be formed using the same adhesive or pressure-sensitive adhesive as the transparent adhesive layer. The thickness of the transparent bonding layer can generally be about 1 μm or more, or about 2 μm or more, about 30 μm or less, or about 15 μm or less.

In embodiments where the graphic film has a retroreflective layer, any layer of the graphic film that is in the path of light incident on and reflected from the graphic film contains an infrared absorber, such as cesium tungsten oxide (CWO), an oxidizing Whiteness enhancing materials such as titanium, zinc oxide, and optical brighteners may also be included.

The graphic film should be applied on the non-yellowing transparent polyurethane layer and/or the white adhesive layer for the purpose of protecting the non-yellowing transparent polyurethane layer and/or the white adhesive layer during manufacturing, transportation, storage or use. may have a liner in the

Liners include, for example, paper; plastic materials such as polyethylene, polypropylene, polyester, cellulose acetate; laminated paper coated with such plastic materials; These liners may have a release treated surface such as with silicone. The thickness of the liner can generally be greater than or equal to about 5 μm, greater than or equal to about 15 μm, or greater than or equal to about 25 μm, less than or equal to about 300 μm, less than or equal to about 200 μm, or less than or equal to about 150 μm.

In one embodiment, the thickness of the graphic film is no greater than about 200 microns, no greater than about 150 microns, or no greater than about 120 microns. The thickness of the graphic film does not include the thickness of the liner. In this embodiment, the followability of the graphic film to the embossed portion can be further enhanced.

In one embodiment, the thickness of the graphic film is about 50 μm or greater, about 60 μm or greater, or about 80 μm or greater. This embodiment can impart the required strength to the graphic film for license plate applications.

From a durability standpoint, the graphic film advantageously has a breaking strength of about 5 N/25 mm or more, about 10 N/25 mm or more, or about 20 N/25 mm or more. The graphic film advantageously has a breaking strength of about 200 N/25 mm or less, about 175 N/25 mm or less, or about 150 N/25 mm or less from the standpoint of manufacturability. In the present disclosure, breaking strength is a value measured according to JIS Z 0237.

The graphic film advantageously has a 5% elongation tension of about 60 N/25 mm or less, or about 50 N/25 mm or less from the viewpoint of preventing cracking during embossing or debossing and preventing lifting from the base plate. . The graphic film advantageously has a 5% elongation tension of about 1 N/25 mm or more, or about 2 N/25 mm or more, from a mechanical strength point of view. In the present disclosure, the 5% elongation tension is a value measured according to JIS Z 0237.

The graphic film of the present disclosure has excellent impact resistance at low temperatures. In one embodiment, according to JIS K5600-5-3 (ASTM D 2794), the film does not crack when an impact resistance test is performed at a test temperature of 0 ° C., -10 ° C., or -20 ° C. . In the impact resistance test, IM-201 DuPont (registered trademark) type testing machine (Tester Sangyo Co., Ltd.) was used, and the weight was dropped onto the surface of the graphic film with a weight of 500 gf, a drop height of 500 mm, and a striking core diameter of 6.3 mm. This is done by checking the appearance of the

A graphic film can be produced, for example, by the following method. The image-receiving layer composition is coated and dried on the release-treated liner to form a non-yellowing polyurethane image-receiving layer. Next, a white adhesive is applied onto the liner with release treatment and dried to form a white adhesive layer. By laminating the image-receiving layer and the white adhesive layer facing each other, an image-receiving film sandwiched between the liners is produced. The liner on the image-receiving layer of the image-receiving film is removed, and a graphic image layer is formed on the image-receiving layer by ink jet printing or the like to produce an image-bearing film.

Then, the transparent polyurethane layer composition is applied onto the liner with release treatment and dried to form a non-yellowing transparent polyurethane layer. Next, a transparent adhesive is applied onto the liner with release treatment and dried to form a transparent adhesive layer. An overlaminate film is produced by laminating a non-yellowing transparent polyurethane layer and a transparent adhesive layer facing each other and removing the liner.

The graphic film can be obtained by laminating the overlaminate film to the image carrier film such that the transparent adhesive layer of the overlaminate film faces the graphic image layer of the image carrier film.

Usual coaters such as bar coaters, knife coaters, roll coaters, die coaters and gravure coaters can be used as coating means. An image-receiving layer composition or a transparent polyurethane layer composition may be formed into a film by melt extrusion or the like, and laminated to a white adhesive layer or a transparent adhesive layer to produce an image-bearing film or an overlaminate film.

In one embodiment, a graphic film laminate plate is provided comprising the above graphic film and a base plate. A graphic film laminate plate can be formed by applying a graphic film on or over a base plate. "Above the baseplate" means that the graphic film is applied in direct contact with the baseplate, and "above the baseplate" means that the graphic film is not in direct contact with the baseplate, e.g. It means that it is arranged via other layers such as a base coating layer. The same applies to the definitions of "upper" and "above" referred to other layers in this disclosure.

A metal plate or a resin plate can generally be used as the base plate. Examples of metal plates include aluminum plates, stainless steel plates, and iron plates. Examples of resin plates include polycarbonate plates, polyester plates, and vinyl chloride plates. If necessary, these plate materials may be molded into a shape such as a frame.

In one embodiment, a license plate is provided that includes the above graphic film and a base plate. In one embodiment, the license plate is non-reflective.

License plates may generally include numbers, letters, graphics, patterns, or combinations thereof. In one embodiment, the appearance of the license plate is government and/or jurisdictional. In another embodiment, the display of numbers, letters, etc. can be formed using a printed layer. In still another embodiment, the display portion can be formed by combining an embossed portion (convex portion) or debossed portion (concave portion) and a printed layer. The depth of the embossed and debossed portions is generally about 1 mm or more and about 2 mm or less, respectively, but is not limited to this range.

The print layer is generally formed using a solvent-based ink called roll coat ink. The printing layer is formed by applying an ink composition containing a pigment and a binder such as a melamine resin, an alkyd resin, a urethane resin, or a mixed resin thereof using roll coating onto the non-yellowing transparent polyurethane layer of the graphic film, It can be formed by baking at a predetermined temperature and time. As the ink composition, specifically, NSP-UP 401K-1 Green (Nikko Vicks Co., Ltd.), MEG screen ink (Teikoku Ink Mfg. Co., Ltd.), which is a one-component heat-curable ink, and the like can be used. .

In one embodiment, a method of manufacturing a license plate includes the steps of providing a base plate, applying a graphic film as described above on or above the base plate to form a graphic film laminate plate, and embossing the graphic film laminate plate. The steps of texturing or debossing and forming a print layer in the raised or recessed portions of the embossed or debossed graphic film laminate plate.

A method of manufacturing a license plate of the present disclosure will be exemplarily described with reference to FIGS. 2A to 2E, but the method of manufacturing a license plate is not limited thereto.

The graphic film shown in FIG. 2A has a liner 40 disposed over the white adhesive layer of graphic film 10 .

As shown in FIG. 2B, a graphic film laminate plate 60 is formed by removing the liner 40 and adhering and laminating the white adhesive layer to a base plate 50 such as an aluminum plate.

Next, as shown in FIG. 2C, a blank press die 70 is used to blank press and cut the graphic film laminate plate 60 into a desired size.

As shown in FIG. 2D, the cut-out graphic film laminate plate 60 is embossed and/or debossed at room temperature to form the display portion and peripheral frame portion of the license plate. In FIG. 2D, the raised portion (embossed portion) is shown as the base of the display portion. The frame portion can give strength to the license plate to prevent deformation of the license plate.

As shown in FIG. 2E, a printed layer 62 is formed on the convex portions (embossed portions) of the embossed graphic film laminate plate 60 by roll coating or the like. In this manner, a license plate containing the graphic film 10 can be produced. In one embodiment, the graphic film has excellent solvent resistance and can be used as is after printing a printing layer without further applying a clear protective layer to the top surface of the license plate.

The graphic film of the present disclosure can be applied, for example, to traffic signs, billboards, etc., in addition to the license plates described above. The graphic films of the present disclosure can also be used as automotive or architectural decorative films or sheets, and the like.

The following examples illustrate specific embodiments of the present disclosure, but the invention is not limited thereto. All parts and percentages are by weight unless otherwise specified.

Table 1 shows the materials used in this example.

Example 1
Preparation of Image-Receiving Layer Composition PU1 and PU2 were mixed using a mixer (TK Auto Homo Mixer, Primix Co., Ltd.) to prepare an image-receiving layer composition (polyurethane resin composition). The compounding ratio of PU1 and PU2 was 100:10 in terms of solid content. The solids content of the composition was about 30%.

Preparation of White Adhesive A premix of white pigment and dispersant was prepared. The premix contained PG1, D1 and methyl ethyl ketone (MEK), and the mixing ratio of PG1 and D1 was 5:1 in terms of solid content. The solids content of the composition was about 66%. A white adhesive was prepared by mixing the premix with ADH1. The compounding ratio of ADH1, PG1 and D1 was 100:50:10 in terms of solid content. CL1 was added to the white adhesive. The compounding ratio of ADH1 and CL1 was 100:0.2 in terms of solid content. The solids content of the composition was about 35%.

Preparation of image-bearing film The image-receiving layer composition was coated on a 50 µm-thick polyester film (JCW2000, 3M Japan Co., Ltd.) with release treatment using a knife coater and dried at 95°C for 5 minutes to obtain a transparent film having a thickness of about 20 µm. A non-yellowing polyurethane image-receiving layer was obtained. Next, the white adhesive was coated on a silicone-treated double-sided polyethylene laminated release paper with a knife coater and dried at 95° C. for 5 minutes to obtain a white adhesive layer having a thickness of about 65 μm. The white adhesive layer and the image-receiving layer were laminated, the polyester film was removed, and a graphic image layer having a thickness of 6 μm was formed on the image-receiving layer by inkjet printing to obtain an image-bearing film.

Preparation of Overlaminate Film A reactive polyurethane composition (two-part type) was prepared using AP1 and ISO1. The compounding ratio of AP1 and ISO1 was 100:39 in terms of solid content. A mixture of AP1 and ISO1 was coated on a 50 μm thick polyester film (ACW200, 3M Japan Co., Ltd.) with a release treatment using a knife coater, dried at 95° C. for 2 minutes and 155° C. for 2 minutes, and dried to a thickness of about 5 μm. A non-yellowing transparent polyurethane layer was obtained. ADH1 and CL2 were then mixed to prepare a transparent adhesive. The compounding ratio of ADH1 and CL2 was 100:0.2 in terms of solid content. The transparent adhesive was coated on a silicone-treated double-sided polyethylene-laminated release paper with a knife coater and dried at 95° C. for 5 minutes to obtain a transparent adhesive layer with a thickness of about 10 μm. The transparent adhesive layer and the non-yellowing transparent polyurethane layer were laminated together, and the polyester film was removed to obtain an overlaminate film.

Preparation of Graphic Film The graphic film of Example 1 was obtained by laminating the overlaminate film to the image carrier film such that the transparent adhesive layer of the overlaminate film faced the graphic image layer of the image carrier film. The graphic film of Example 1 comprises, from the top, an overlaminate film (a non-yellowing transparent polyurethane layer with a thickness of 5 μm and a transparent adhesive layer with a thickness of 10 μm), an image carrier film (inkjet printing layer, a transparent non-yellowing polyurethane image with a thickness of 20 μm). a receiving layer, a white adhesive layer having a thickness of 65 μm), and a release paper.

Example 2
A graphic film of Example 2 was prepared in the same manner as in Example 1, except that the thickness of the non-yellowing transparent polyurethane layer was changed to 10 μm.

Example 3
A graphic film of Example 3 was prepared in the same manner as in Example 1, except that the thickness of the non-yellowing transparent polyurethane layer was changed to 20 μm.

Example 4
A graphic film of Example 4 was prepared in the same manner as in Example 1, except that the thickness of the non-yellowing transparent polyurethane layer was changed to 30 μm.

example 5
Preparation of Image-Receiving Layer Composition PU1 and PU2 were mixed using a mixer (TK Auto Homo Mixer, Primix Co., Ltd.) to prepare an image-receiving layer composition (polyurethane resin composition). The compounding ratio of PU1 and PU2 was 100:10 in terms of solid content. The solids content of the composition was about 30%.

Preparation of White Adhesive A premix of white pigment and dispersant was prepared. The premix contained PG1, D1 and methyl ethyl ketone (MEK), and the mixing ratio of PG1 and D1 was 5:1 in terms of solid content. The solids content of the composition was about 66%. A white adhesive was prepared by mixing the premix with ADH1. The compounding ratio of ADH1, PG1 and D1 was 100:50:10 in terms of solid content. CL1 was added to the white adhesive. The compounding ratio of ADH1 and CL1 was 100:0.2 in terms of solid content. The solids content of the composition was about 35%.

Preparation of image-bearing film The image-receiving layer composition was coated on a 50 µm-thick polyester film (JCW2000, 3M Japan Co., Ltd.) with release treatment using a knife coater and dried at 95°C for 5 minutes to obtain a transparent film having a thickness of about 20 µm. A non-yellowing polyurethane image-receiving layer was obtained. Next, the white adhesive was coated on a silicone-treated double-sided polyethylene laminated release paper with a knife coater and dried at 95° C. for 5 minutes to obtain a white adhesive layer having a thickness of about 30 μm. The white adhesive layer and the image-receiving layer were laminated, the polyester film was removed, and a graphic image layer having a thickness of 6 μm was formed on the image-receiving layer by inkjet printing to obtain an image-bearing film.

Preparation of Overlaminate Film The image-receiving layer composition was coated on a 50 μm-thick polyester film (ACW200, 3M Japan Co., Ltd.) with release treatment using a knife coater and dried at 95° C. for 5 minutes to form a non-yellow film having a thickness of about 20 μm. A modified transparent polyurethane layer was obtained. ADH1 and CL2 were then mixed to prepare a transparent adhesive. The compounding ratio of ADH1 and CL2 was 100:0.2 in terms of solid content. The transparent adhesive was coated on a silicone-treated double-sided polyethylene-laminated release paper with a knife coater and dried at 95° C. for 5 minutes to obtain a transparent adhesive layer with a thickness of about 30 μm. The transparent adhesive layer and the non-yellowing transparent polyurethane layer were laminated together, and the polyester film was removed to obtain an overlaminate film.

Preparation of Graphic Film The graphic film of Example 5 was obtained by laminating the overlaminate film to the image carrier film such that the transparent adhesive layer of the overlaminate film faced the graphic image layer of the image carrier film. The graphic film of Example 5 comprises, from the top, an overlaminate film (a 20 μm thick non-yellowing transparent polyurethane layer and a 30 μm thick transparent adhesive layer), an image carrier film (an inkjet printing layer, and a 20 μm thick transparent non-yellowing polyurethane image. A receiving layer, a white adhesive layer having a thickness of 30 μm), and a release paper.

Example 6
A graphic film of Example 6 was prepared in the same manner as in Example 5 except that the thickness of the non-yellowing transparent polyurethane layer was changed to 10 μm.

Example 7
A graphic film of Example 7 was produced in the same manner as in Example 5, except that the thickness of the white adhesive layer of the image carrier film was changed to 65 μm.

Example 8
A graphic film of Example 8 was produced in the same manner as in Example 5 except that the thickness of the non-yellowing transparent polyurethane layer was changed to 10 μm and the thickness of the white adhesive layer of the image carrier film was changed to 65 μm.

Example 9
A graphic film of Example 9 was produced in the same manner as in Example 5 except that the thickness of the white adhesive layer of the image carrier film was changed to 40 μm.

example 10
A graphic film of Example 10 was prepared in the same manner as in Example 5 except that the thickness of the non-yellowing transparent polyurethane layer was changed to 10 μm and the thickness of the white adhesive layer of the image carrier film was changed to 40 μm.

Comparative example 1
An overlaminate film consisting of a non-yellowing transparent polyurethane layer with a thickness of 150 μm and a transparent adhesive layer with a thickness of 40 μm was produced. An image carrier film was prepared comprising a 6 μm thick inkjet printed layer, a 70 μm thick transparent non-yellowing polyurethane image receiving layer, and a 30 μm thick white adhesive layer. A graphic film of Comparative Example 1 was produced by laminating the ink-jet printed surfaces of the overlaminate film and the image-bearing film.

Comparative example 2
An overlaminate film consisting of a 50 μm thick transparent polyvinyl chloride film layer and a 30 μm thick transparent acrylic adhesive layer was produced. An image-bearing film comprising an ink-jet printing layer with a thickness of 6 μm, a white polyvinyl chloride film image-receiving layer with a thickness of 90 μm, and a transparent acrylic pressure-sensitive adhesive layer with a thickness of 30 μm was prepared. A graphic film of Comparative Example 2 was produced by laminating the ink-jet printed surfaces of the overlaminate film and the image-bearing film.

Comparative example 3
An overlaminate film comprising a non-yellowing transparent polyurethane layer with a thickness of 20 μm and a transparent adhesive layer with a thickness of 10 μm was produced. An image carrier film was prepared comprising a 6 μm thick inkjet printed layer, a 50 μm thick transparent non-yellowing polyurethane image receiving layer, and a 20 μm thick white adhesive layer. A graphic film of Comparative Example 3 was produced by laminating the ink-jet printed surfaces of the overlaminate film and the image-bearing film.

Comparative example 4
An overlaminate film consisting of a non-yellowing transparent polyurethane layer with a thickness of 10 μm and a transparent adhesive layer with a thickness of 10 μm was produced. An image carrier film was prepared comprising a 6 μm thick inkjet printed layer, a 40 μm thick transparent non-yellowing polyurethane image receiving layer, and a 20 μm thick white adhesive layer. A graphic film of Comparative Example 4 was produced by laminating the ink-jet printed surfaces of the overlaminate film and the image-bearing film.

5% Elongation Tensile Test piece was measured according to JIS Z 0237.

Embossability test A test piece was attached to a 1 mm thick aluminum plate (A1100) at room temperature. Chinese characters and numerals were embossed on the test piece with an embossing machine (Amada Co., Ltd.). The embossing pressure was approximately 15 MPa. The embossing die spacing was about 1.25 mm. A cross section of the test piece was observed with an optical microscope. When no lift of the test piece was confirmed from the aluminum plate, it was judged as "good". When it was confirmed that the test piece was lifted from the aluminum plate, it was determined as "defective".

Impact resistance test An impact resistance test was performed according to JIS K5600-5-3 (ASTM D 2794). An IM-201 DuPont® type tester (Tester Sangyo Co., Ltd.) was used. A weight of 500 gf, a drop height of 500 mm, and a striking core diameter of 6.3 mm were dropped on the surface of the graphic film to check the appearance. The test temperatures were 0°C, -10°C and -20°C. When no film crack was confirmed, it was judged as "good". When film cracking was confirmed, it was determined as "defective".

Table 2 shows the evaluation results.

Some of the embodiments of the present invention are described in aspects 1-10 below.
[Aspect 1]
A non-PVC graphic film for license plates, comprising (A) an overlaminate film and (B) an image-bearing film,
The overlaminate film comprises (a1) a non-yellowing transparent polyurethane layer and (a2) a transparent adhesive layer,
The image-bearing film comprises (b1) a graphic image layer, (b2) a non-yellowing polyurethane image-receiving layer, and (b3) a white adhesive layer,
the overlaminate film is laminated to the image carrier film via the transparent adhesive layer so as to cover at least a portion of the graphic image layer;
A graphic film, wherein the total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer is smaller than the total thickness of the transparent adhesive layer and the white adhesive layer.
[Aspect 2]
The graphic film of aspect 1, wherein said non-yellowing polyurethane image-receiving layer of said image bearing film is transparent.
[Aspect 3]
3. The graphic film of any of aspects 1 or 2, wherein the non-yellowing polyurethane image-receiving layer of the image-bearing film comprises a polyether-based polyurethane.
[Aspect 4]
The graphic film according to any one of aspects 1 to 3, wherein the graphic film has a thickness of 200 μm or less.
[Aspect 5]
The graphic film according to any one of modes 1 to 4, wherein the total thickness of the non-yellowing transparent polyurethane layer of the overlaminate film and the non-yellowing polyurethane image-receiving layer of the image-bearing film is 80 μm or less.
[Aspect 6]
The graphic film of any one of aspects 1-5, wherein the graphic image layer of the image bearing film is an inkjet printed layer.
[Aspect 7]
According to any one of aspects 1 to 6, wherein the non-yellowing transparent polyurethane layer of the overlaminate film comprises a cured product of a reactive polyurethane composition containing a (meth)acrylic polyol and a non-yellowing polyisocyanate. graphic film.
[Aspect 8]
A graphic film laminate plate comprising the graphic film of any one of aspects 1-7 and a base plate.
[Aspect 9]
A license plate comprising a graphic film according to any one of aspects 1-7 and a base plate.
[Aspect 10]
providing a base plate;
applying a graphic film according to any one of aspects 1 to 7 onto or above said base plate to form a graphic film laminate plate;
embossing or debossing the graphic film laminate plate;
applying a printing layer to the raised or depressed portions of the embossed or debossed graphic film laminate plate;
A method of manufacturing a license plate, comprising:

REFERENCE SIGNS LIST 10 graphic film 20 overlaminate film 22 non-yellowing transparent polyurethane layer 24 transparent adhesive layer 30 image carrier film 32 graphic image layer 34 non-yellowing polyurethane image-receiving layer 36 white adhesive layer 40 liner 50 base plate 60 graphic film laminate plate 62 printing layer 70 blank press die

Claims (10)

A non-PVC graphic film for license plates, comprising (A) an overlaminate film and (B) an image-bearing film,
The overlaminate film comprises (a1) a non-yellowing transparent polyurethane layer and (a2) a transparent adhesive layer,
The image-bearing film comprises (b1) a graphic image layer, (b2) a non-yellowing polyurethane image-receiving layer, and (b3) a white adhesive layer,
the overlaminate film is laminated to the image carrier film via the transparent adhesive layer so as to cover at least a portion of the graphic image layer;
The total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer is smaller than the total thickness of the transparent adhesive layer and the white adhesive layer,
Ratio of the total thickness of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer to the total thickness of the transparent adhesive layer and the white adhesive layer (the ratio of the non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer) total thickness/total thickness of transparent adhesive layer and white adhesive layer) is less than 1,
The non-yellowing transparent polyurethane layer and the non-yellowing polyurethane image-receiving layer are each composed of a polyol that is an aliphatic compound or an alicyclic compound, an aliphatic polyisocyanate, an alicyclic polyisocyanate, and their burettes and isocyanates. A graphic film formed from a reactive polyurethane composition comprising a polyisocyanate selected from the group consisting of a nurate form or an adduct form . 2. The graphic film of claim 1, wherein said non-yellowing polyurethane image-receiving layer of said image-bearing film is transparent. 3. The graphic film of claim 1, wherein said non-yellowing polyurethane image-receiving layer of said image-bearing film comprises polyether-based polyurethane. The graphic film according to any one of claims 1 to 3, wherein the graphic film has a thickness of 200 µm or less. 5. The graphic film according to claim 1, wherein the total thickness of the non-yellowing transparent polyurethane layer of the overlaminate film and the non-yellowing polyurethane image-receiving layer of the image-bearing film is 80 μm or less. . A graphic film according to any preceding claim, wherein the graphic image layer of the image bearing film is an inkjet printed layer. The non-yellowing transparent polyurethane layer of the overlaminate film is selected from the group consisting of (meth)acrylic polyols, aliphatic polyisocyanates, alicyclic polyisocyanates, and burettes, isocyanurates or adducts thereof. The graphic film according to any one of claims 1 to 6, comprising a cured product of a reactive polyurethane composition containing a non-yellowing polyisocyanate. A graphic film laminate plate comprising the graphic film of any one of claims 1-7 and a base plate. A license plate comprising a graphic film according to any one of claims 1 to 7 and a base plate. providing a base plate;
applying a graphic film according to any one of claims 1 to 7 on or above said base plate to form a graphic film laminate plate;
embossing or debossing the graphic film laminate plate;
applying a printing layer to the raised or depressed portions of the embossed or debossed graphic film laminate plate;
A method of manufacturing a license plate, comprising:

Images