KR20090116863A - Polyurethane protection film with double protective function from ultraviolet rays - Google Patents

Abstract

PURPOSE: A polyurethane protective film having double ultraviolet protection functions is provided to prevent deformation and discoloration of the protective film due to ultraviolet rays, and to offer good applicability. CONSTITUTION: A polyurethane protective film having double ultraviolet protection functions includes a urethane substrate film containing an inorganic ultraviolet screening agent and a urethane coating layer which is formed by applying urethane coating liquid on a side of the urethane substrate film. The urethane coating liquid comprises the inorganic ultraviolet screening agent and an organic ultraviolet screening agent. An acryl-based adhesive layer is formed on a rear side of the urethane substrate film.

Description

Polyurethane protective film with double UV protection function {POLYURETHANE PROTECTION FILM WITH DOUBLE PROTECTIVE FUNCTION FROM ULTRAVIOLET RAYS}

The present invention relates to a polyurethane protective film having a double UV protection function, and more particularly, ultraviolet rays are primarily blocked by a sunscreen contained in a urethane coating layer located on the outermost side of the protective film, where the inside of the film is not blocked. It relates to a polyurethane protective film that is completely blocked in the entire wavelength range of the ultraviolet rays by the secondary ultraviolet rays transmitted by the secondary blocking by the sunscreen contained in the substrate film.

The internal and external appearance of structures such as buildings, automobiles, ships, etc. are the external physical harmful substances such as stones, sand, and artificial collisions, and UV, acid rain, yellow sand, snow calcium chloride, salt-containing wind, emissions and algae Constant exposure to chemical hazards such as As a result, the structure is changed in its own color, luster and appearance and is easily damaged, and living organisms living inside the structure are directly or indirectly affected.

Therefore, most of the methods developed to protect the appearance of structures such as buildings, automobiles, ships, etc. from external harmful substances are related to protective films manufactured using various polymers. [Japanese Patent Laid-Open No. 1995-029399] And United States Patent No. 6,709,738.

At this time, the polyurethane in the polymer has a variety of physical and chemical properties according to the manufacturing method, in particular, it has a high elasticity, wear resistance, impact resistance, weather resistance and chemical resistance is suitable for use as a protective film.

However, the polyurethane film exhibits discoloration and discoloration such as yellowing when exposed to ultraviolet rays for a long time due to its structural characteristics, and is discolored by external colorants introduced from rainwater or detergents concentrated in the film, and thus there is a limit to application to exterior structures.

In order to solve this problem, US Pat. No. 6,395,390 is a protective film for protecting the exterior coating of automobiles and ships, and has developed a polyurethane film having a pressure-sensitive adhesive layer on the surface. There has been known a method for preventing discoloration or deionization. However, this method did not fundamentally solve the problem of discoloration of the polyurethane itself.

In general, the surface of the structure and the discoloration of the protective film is known to be caused by long-term exposure to ultraviolet light, but only a technique of adding a sunscreen has been disclosed, resulting in less than 10% transmittance at 190 ~ 370nm wavelength have.

In Japanese Patent Laid-Open No. 7-29399, an acrylic resin, ethylene-vinyl acetate copolymer resin, and polyester resin having excellent durability on one surface of a flexible resin film for the purpose of remarkably discoloration or gloss reduction due to long-term outdoor use of a car. The protective film which laminates the colored film obtained from etc., and adheres an adhesive and a release paper on the back surface is known. At this time, the colored film is metal powder such as gold, silver, copper, aluminum powder, inorganic pigments such as titanium dioxide, organic pigments such as cyanine, quinacridone, ultraviolet absorber, radical scavenging agent, antioxidant Agents and the like can be used together.

As another example, Japanese Laid-Open Patent Publication No. 7-291680 discloses a small amount of a specific dope metal in zinc oxide powder in order to improve the infrared and ultraviolet blocking functions of glass for building and vehicle use and to provide an economical construction method. In combination with resins, various compositions have been formed, and new compositions having a UV blocking function and near-infrared reflectivity have been published.

However, the above technique does not reach the ultraviolet perfection blocking purpose because the blocking of the entire ultraviolet wavelength range (200 to 400nm) is not complete.

In general, ultraviolet light has a wavelength of 200 to 400 nm, more specifically UVC (short wavelength ultraviolet light) having a wavelength of 200 to 280 nm, UVB (medium wavelength ultraviolet light) having a wavelength of 280 to 320 nm and UVA (long wavelength) having a wavelength of 320 to 400 nm. Ultraviolet light). UVC is of little concern in UV protection because it has the shortest wavelength and is scattered and removed before reaching most of the earth's surface. Most products that require UV protection have been focused on blocking UVB, but recently, a lot of harmful effects on UVA have been raised. It has been active.

UVA does not cause immediate harmful effects such as erythema like UVB, but has the highest amount of reaching the surface and continues to accumulate over long-term exposure, resulting in more dangerous results than UVB. In particular, UVA has a relatively long wavelength and can penetrate deep into the protective film, resulting in discoloration of the protective film and deformation of the adhesive layer connecting the protective film and the protective surface, or further promoting the appearance change of the protective surface itself. In addition, the high permeability to the building wall or glass wall not only causes discoloration or glossiness of the exterior of the vehicle or building, but also easily reaches the people inside and penetrates into the skin, causing skin aging, genetic modification, and cancer. .

Accordingly, the present inventors have steadily tried to completely block ultraviolet rays in the entire UV region, and as a result, a poly urethane substrate layer containing an inorganic sunscreen and an urethane coating layer containing an inorganic sunscreen and an organic sunscreen on the urethane substrate film The present invention was completed by confirming that the urethane protective film blocks UV rays at 99% or more in the entire UV wavelength range (200 to 400 nm).

It is an object of the present invention to provide a polyurethane protective film that blocks ultraviolet rays at 99% or more in the entire wavelength range of 200 to 400 nm.

Another object of the present invention is to improve the discoloration and deformation of the protective film by ultraviolet light, to provide a polyurethane protective film applicable to the external structure exposed to ultraviolet light for a long time.

In order to achieve the above object, the present invention is a structure consisting of a urethane substrate film containing an inorganic sunscreen agent and a urethane coating layer formed by coating a urethane coating liquid mixed with an inorganic sunscreen agent and an organic sunscreen agent on at least one surface of the urethane substrate film. , To provide a polyurethane protective film having a double UV protection function.

In this case, an acrylic adhesive layer may be further formed on the rear surface of the urethane substrate film having the urethane coating layer formed thereon.

The urethane substrate film contains 0.1 to 20% by weight of an inorganic sunscreen, the urethane coating solution is a known urethane coating liquid used in forming a conventional urethane bond, 0.1 to 20% by weight of an inorganic sunscreen and 0.1 to an organic sunscreen. 20% by weight is mixed, more preferably 10 to 65% by weight of polyisocyanate, 10 to 65% by weight of polyol, 0.1 to 20% by weight of inorganic sunscreen and 0.1 to 20% by weight of organic sunscreen, and 0.1 to 2 catalyst % By weight is in the form of dispersion in a solvent. In this case, any one or more selected from the group consisting of titanium dioxide, zinc oxide, manganese oxide, zirconium dioxide, and cerium dioxide having an aperture of 200 nm or less may be used, and the inorganic sunscreen may be silicon, metal It may be surface treated with any one selected from the group consisting of fatty acids and silicas.

The organic sunscreen may be any one selected from the group consisting of p-aminobenzoic acid derivatives, benzylidene camphor derivatives, cinnamic acid derivatives, benzophenone derivatives and benzotriazole derivatives.

The polyol may be used any one or more selected from the group consisting of polycarbonate, polyester, polyacrylate and poly alkylene, wherein the weight average molecular weight is preferably 50 to 5,000. In addition, the polyol may contain a low molecular weight crosslinking agent having a weight average molecular weight of 20 to 500 within 50% by weight.

Furthermore, the polyurethane protective film having a double UV protection function of the present invention can be applied to the exterior structure of automobiles, ships or buildings.

Polyurethane protective film of the present invention is blocked more than 99% in the full wavelength range (200 ~ 400nm) of the ultraviolet rays as the ultraviolet rays are blocked, in particular, as the UVA is completely blocked, discoloration and deformation of the protective film and the protective surface This remarkably improved polyurethane protective film can be provided.

Thus, the polyurethane protective film of the present invention, while maintaining the high elasticity and high-strength properties of the polyurethane, and completely block the ultraviolet rays due to the double UV protection function, there is no discoloration and discoloration of the appearance of the product even in the long-term use and maintain the gloss As the surface is protected from physicochemical and harmful substances, the original shape of the product can be maintained for a long time, so it can be used for exterior structures of automobiles, ships or buildings.

Furthermore, the polyurethane protective film of the present invention can also prevent the occurrence of diseases such as skin diseases, genetic modification and cancer caused by ultraviolet rays reaching living organisms living in cars, ships, buildings.

Hereinafter, the present invention will be described in more detail.

The present invention is a urethane substrate film containing an inorganic sunscreen; And it provides a polyurethane protective film having a double UV protection function consisting of a urethane coating layer formed by coating a urethane coating liquid mixed with an inorganic sunscreen and an organic sunscreen on at least one surface of the urethane substrate film.

In addition, the present invention is the structure of the acrylic pressure-sensitive adhesive layer formed by coating an acrylic resin such as methyl methacrylate, n-butyl acrylate, n-octyl acrylate and acrylic acid on the back surface of the urethane substrate film formed with the urethane coating layer Polyurethane protective film.

1. Urethane Substrate Film

The urethane substrate film serves as a physicochemical protective function, the urethane substrate film of the present invention 0.1 to 20% by weight of inorganic sunscreen, more preferably 0.2 to 5% by weight, even more preferably 0.5 to 2% by weight It is prepared in the form of a transparent film by mixing and extruding. If the inorganic sunscreen is less than 0.1% by weight, the blocking effect of the UVA is not sufficient, if more than 20% by weight, there is a problem that the physical properties of the urethane substrate film such as transparency and elasticity of the film is lowered.

At this time, the inorganic sunscreen is to block the ultraviolet light through the absorption or scattering of ultraviolet light, titanium dioxide (TiO ₂ ) or zinc oxide (ZnO) having a diameter of 200nm or less is used alone or in a mixed form, in addition to manganese oxide ( MnO), zirconium dioxide (ZrO ₂ ), cerium dioxide (CeO ₂ ), and the like may be used.

In particular, titanium dioxide and zinc oxide are excellent materials for absorbing and scattering ultraviolet rays in the UVA region. In particular, titanium dioxide and zinc oxide have the best effect on absorption and scattering ability when used in a particulate state of 200 nm or less. That is, the titanium dioxide (TiO ₂ ) absorbs the wavelength of 405nm or less mainly and scatters the wavelength above it to block ultraviolet rays, and zinc oxide (ZnO) absorbs the wavelength of 385nm or less and scatter the wavelength above the ultraviolet ray Block it.

The inorganic sunscreen agent is mainly effective to block ultraviolet rays of the UVA region and is chemically stable, but when present in the form of fine particles, it exhibits photoactivity, thus affecting stability by radical generation when directly used. In particular, in order to realize the transparency of the substrate film required in the present invention, the diameter of the inorganic sunscreen particles is preferably 1 μm or less, and in order to maximize the absorption and scattering power of ultraviolet rays, 200 nm or less, more preferably 50 to 200 nm in size. As the particles are used, a surface treatment for suppressing photoactivity is required. In addition, the inorganic sunscreens are poor in solubility in hydrophilic dispersions and require surface treatment for easy use.

In this case, the surface treatment is surface-treated with any one surface treatment agent selected from the group consisting of silicon, metal fatty acid and silica on the selected inorganic sunscreen, thereby improving stability and solubility. More preferably, surface treatment using silicon is preferable.

The urethane base film is made of a transparent urethane substrate film that provides physical and chemical protection of 10 to 500 mm in thickness, breaking strength of about 400 kg / cm and elongation rate of 200 to 600% by extrusion molding a mixture of urethane resin and inorganic sunscreen. .

2. Urethane coating layer

The urethane coating layer is located on the outermost layer of the polyurethane protective film of the present invention, by containing an inorganic sunscreen agent and an organic sunscreen agent in the usual urethane coating liquid, thereby primarily blocking ultraviolet rays from the outside.

The urethane coating liquid of the present invention contains a mixing ratio between the main polyisocyanate and the polyol within a range satisfying 0.8 to 1.2 equivalent ratio, more preferably 1: 1 equivalent ratio. More specifically, the urethane coating liquid of the present invention is 10 to 65% by weight of polyisocyanate, 10 to 65% by weight of polyol, 0.1 to 20% by weight of inorganic sunscreen, 0.1 to 20% by weight of organic sunscreen and 0.1 to 2% by weight of catalyst. It is prepared by dispersing in an organic solvent. Coating on at least one surface of the urethane base film to produce a urethane protective film of the present invention. At this time, the coating method may be used maya coating, spray coating, screen printing, rotary screen coating and gravure coating.

Looking at each composition constituting the urethane coating solution of the present invention, the polyisocyanate is preferably a chain isocyanate to minimize discoloration of the protective film, it contains 10 to 65% by weight relative to the total coating liquid, more preferably 40 to 50 It contains% by weight. At this time, if the polyisocyanate is less than 10% by weight, an excessive amount of unreacted polyol is present, resulting in physicochemical defects such as water resistance or reduced strength of the coated surface. The physical properties of the resin are not sufficient, and problems such as stability and discoloration of the coated surface occur, which is not preferable.

The polyol may be used alone or in a mixed form selected from the group consisting of polycarbonates, polyesters, polyethers, polyacrylates and polyalkylenes, and it is preferable to use materials having an average molecular weight of 50 to 5,000. At this time, if the average molecular weight is less than 50, the strength, elongation and flexibility of the coated surface is not sufficient, and if the average molecular weight is more than 5,000, it is not preferable because there is a problem in physical properties such as strength due to failure to obtain an appropriate amount of crosslinking.

The polyol preferably contains 10 to 65% by weight with respect to the total coating liquid. When the polyol is less than 10% by weight, the target elongation or flexibility is not obtained. When the polyol is more than 65% by weight, the unreacted polyol is present in an excessive amount to provide stability and It is not preferable because there is a problem in physical properties such as strength.

In addition, the polyol solution may contain a low molecular weight crosslinking agent having an average molecular weight of 20 to 500 within 50% of the total polyol usage. When the content of the crosslinking agent exceeds 50% of the polyol content, the target strength and flexibility are increased. It is not desirable because it is not obtained. At this time, the crosslinking agent includes butanediol, hexanediol, ethylene glycol, propylene glycol, pentaerythritol, glycerin, sucrose, sorbitol, trimethanol propane, ethylenediamine and the like.

Since the inorganic sunscreen used in the urethane coating layer of the present invention uses the same material as the inorganic sunscreen contained in the urethane base film, detailed description of the material will be omitted. However, the inorganic sunscreen used in the urethane coating layer is used in an amount of 0.1 to 20% by weight, more preferably 0.5 to 5% by weight, even more preferably 1 to 5% by weight based on the total coating liquid. At this time, if the content of the inorganic sunscreen is less than 0.1% by weight, the blocking effect of the UVA is not sufficient, if the content exceeds 20% by weight, the physical properties of the urethane substrate film such as transparency and elasticity of the film is lowered.

The organic sunscreen used in the urethane coating layer of the present invention has a maximum absorption wavelength of 280 to 350 nm and is used for UVB blocking purposes. Preferred examples include a group consisting of a p-aminobenzoic acid derivative, a benzylidene camphor derivative, a cimmamic acid derivative, a benzophenone derivative and a benzotriazole derivative. The use of any one selected from is preferred, the manufacturing environment of the protective film is a high temperature of 120 ℃, considering the long-term use of the protective film under UV conditions, the use of benzotriazole derivatives is particularly preferred.

The organic sunscreen agent is preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, even more preferably 0.5 to 5% by weight based on the total coating liquid. At this time, if less than 0.1% by weight, the ultraviolet ray blocking function is not sufficient, if it exceeds 20% by weight, the solubility is lowered during the production of the urethane coating solution and the physical properties of the coating surface is not preferable.

As the catalyst used in the urethane coating solution of the present invention, a metal compound catalyst such as Sn, Pb, Hg and an amine catalyst may be used, but it is important to use a metal compound catalyst to prevent discoloration of the protective film, which is an important object of the present invention. It is preferable to use tin compounds, such as dibutyl tin diacetate and dibutyl tin dilaurate, in particular at a concentration of 0.1 to 2%.

In addition, in consideration of the solubility and viscosity of the material used, an organic solvent may be used, and any one selected from the group consisting of toluene, methyl ethyl ketone, ethyl acetate, cyclohexane, and tetrahydrofuran may be used. In particular, use of methyl ethyl ketone is preferable. If necessary, additives such as antioxidants and light stabilizers may be further contained.

Furthermore, the polyurethane protective film having a double UV protection function of the present invention can be utilized as a product protective film in various fields, and particularly, it is advantageous to apply to exterior structures of structures such as automobiles, ships, and buildings. That is, the polyurethane protective film having a double UV protection function of the present invention is primarily blocked by UVA and UVB on the urethane coating layer containing an inorganic sunscreen and an organic sunscreen, the extra UVA penetrating the urethane coating layer is an inorganic sunscreen As the secondary block on the urethane substrate film containing the UV entire wavelength region (200 ~ 400nm) is blocked with a high efficiency of more than 99%.

Accordingly, the polyurethane protective film of the present invention can improve the discoloration of the protective film and the protective surface and deformation of the adhesive layer by UVA, in addition to the basic physicochemical protective function as a protective film by maintaining high elasticity and high strength properties from the polyurethane. When applied to the exterior of structures such as automobiles, ships, and buildings, it is possible to improve problems such as aging of organisms inside the structure, genetic modification, and cancer.

Hereinafter, the present invention will be described in detail by way of examples.

The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

< Example  1> Preparation of Polyurethane Protective Film 1

Step 1: Preparation of Urethane Substrate Film

The mixture containing 1 part by weight of titanium dioxide and 1 part by weight of zinc oxide as an inorganic sunscreen agent in 100 parts by weight of the soft urethane resin was 150 µm thick, breaking strength 400kg / cm ² , and elongation 300% by extrusion molding by a T-die method. A transparent urethane substrate film was prepared.

Step 2: forming a urethane coating layer

48.6 g of polyacryl polyol (equivalent molecular weight 486), 13.3 g of polyisocyanate (equivalent molecular weight 178) and 2.5 g of 1,4-butylene glycol were dissolved in 35 g of ethyl acetate, and then 2,2'-methylene-bis- was used as an organic sunscreen agent. 1 g of [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3, -tetramethylbutyl) phenol] (molecular weight 658.86), 1 g of titanium dioxide and 1 g of zinc oxide as an inorganic sunscreen To prepare a urethane coating solution by adding 0.5 g of Tinuvin-292 as a light stabilizer, 0.05 g of dibutyltin dilaurate as a catalyst, and evenly applying it to a surface of the urethane substrate film prepared in Step 1 with a knife coater 110 Hot air drying at 0 ° C. formed a urethane coating layer having a thickness of 30 μm.

Step 3: acrylic Adhesive layer  formation

50 parts by weight of n-butyl acrylate, 45 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of acrylic acid were dissolved in ethyl acetate to form a 40% solution, and then evenly coated on the back side of the urethane substrate film with a knife coater at 80 ° C. After drying by hot air to form an acrylic pressure-sensitive adhesive layer of 50㎛ thickness, the release paper was bonded to prepare a polyurethane protective film.

< Example  2> Preparation of Polyurethane Protective Film 2

A polyurethane protective film was prepared in the same manner as in Example 1, except that the acrylic adhesive layer was not formed.

< Comparative example  1>

The flexible urethane resin was extruded by a T-die method to prepare a transparent urethane film having a thickness of 150 μm, breaking strength of 400 kg / cm ² , and an elongation rate of 300%.

< Comparative example  2>

The polyurethane protective film was prepared in the same manner as in Example 1, except that the urethane base film was prepared by extrusion molding the soft urethane resin by the T-die method without containing the inorganic sunscreen agent.

< Comparative example  3>

The same procedure as in Example 1 was carried out except that a urethane base film prepared without containing an inorganic sunscreen was used, and a urethane coating layer was prepared without containing titanium dioxide and zinc oxide as an inorganic sunscreen in the urethane coating solution. To prepare a polyurethane protective film.

< Comparative example  4>

A polyurethane protective film was prepared in the same manner as in Example 1 except that a urethane base film prepared without containing an inorganic sunscreen agent was used and a urethane coating layer was prepared without containing an organic sunscreen agent in the urethane coating solution. Prepared.

< Comparative example  5>

The same procedure as in Example 1 was carried out except that the urethane base film was prepared without containing the inorganic sunscreen, and the urethane coating solution was prepared without the organic sunscreen and the inorganic sunscreen. Urethane protective film was prepared.

< Comparative example  6>

A polyurethane protective film was prepared in the same manner as in Example 1, except that the urethane coating solution did not contain titanium dioxide and zinc oxide as an inorganic sunscreen agent, and prepared a urethane coating layer.

< Comparative example  7>

A polyurethane protective film was prepared in the same manner as in Example 1, except that the urethane coating liquid was not contained in the urethane coating solution and thus the urethane coating layer was prepared.

< Experimental Example 1 >

In order to measure the ultraviolet protective ability of the polyurethane protective film prepared in Example 1 and Comparative Examples 1 to 7 prepared above, the film piece from which the release paper was removed was prepared using an ultraviolet spectrophotometer (UV / VIS spectrometer UV2, Unicam). The transmittance in the 200-400 nm wavelength range was measured and shown in Table 1 below.

UV protection of polyurethane protective film division        Total transmittance (%)        % Of total blocks Example 1 <1            > 99 Comparative Example 1 99 One Comparative Example 2 7 93 Comparative Example 3 15 85 Comparative Example 4 17 83 Comparative Example 5 95 5 Comparative Example 6 35 65 Comparative Example 7 40 60

< Experimental Example 2 >

In order to measure the weather resistance of the polyurethane protective film prepared in Example 1 and Comparative Examples 1 to 7 prepared above, the film piece from which the release paper was removed was attached to an aluminum plate and was severely subjected to QUV / Spray (Q-Lab). It evaluated on condition. The test method was measured using ASTM G154cycle 1 with a panel temperature of 60 ° C. and a UVA-340 lamp. Evaluation was performed and evaluated according to the ASTM standard grading system, the experimental results are shown in Table 2 below.

Weather resistance measurement results of polyurethane protective film division       Rating Film quality after severe conditions      Change of appearance of protective film Example 1 10 Excellent No change Comparative Example 1 4 Fair Pronounced change Comparative Example 2 9 * Very slight change Comparative Example 3 8 Very good Slight change Comparative Example 4 8 Very good Slight change Comparative Example 5 6 Good Moderate change Comparative Example 6 5 ** ** Comparative Example 7 5 ** **

* State of first detectable change

** Values between 4 and 6

According to the test results, in order to provide a polyurethane protective film having a double UV protection function, a laminated structure consisting of a urethane substrate film and a urethane coating layer is preferable, and by containing a sunscreen in each layer, the primary ultraviolet ray in the outermost layer After blocking, when blocking the second ultraviolet rays in the inner layer, the optimum conditions were met with a protective film.

In other words, the polyurethane protective film prepared in Example 1 exhibits an efficiency of blocking more than 99% in the entire wavelength range (200-400 nm) of the ultraviolet light and does not show any change in physical properties even under the harsh conditions of UVA. The effect of blocking completely to UVA was confirmed.

On the other hand, the urethane protective film prepared without the inorganic sunscreen and / or the organic sunscreen showed a UV blocking efficiency of 93% or less, and exhibited a change in physical properties when exposed to UV light under severe conditions.

First of all, the present invention is blocked by more than 99% in the entire wavelength range (200 ~ 400nm) as the ultraviolet rays are blocked by double, in particular, as UVA is completely blocked, discoloration and deformation of the protective film and the protective surface is significantly improved. Polyurethane protective film can be provided.

Second, the polyurethane protective film of the present invention, while maintaining the high elasticity and high-strength properties of the polyurethane, and completely block the ultraviolet rays due to the double UV protection function, there is no discoloration and discoloration of the appearance of the product even in the long-term use and maintain the gloss As the surface is protected from physicochemical and harmful substances, the original shape of the product can be maintained for a long time, so it can be used for exterior structures of automobiles, ships or buildings.

Third, the polyurethane protective film of the present invention can also prevent the occurrence of diseases such as skin diseases, genetic modification and cancer caused by ultraviolet rays reaching living organisms living in cars, ships, buildings.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (11)

Urethane substrate film containing an inorganic sunscreen; And A urethane coating layer formed on at least one surface of the urethane substrate film by coating a urethane coating liquid mixed with an inorganic sunscreen and an organic sunscreen; Polyurethane protective film having a double UV protection function, characterized in that consisting of. The polyurethane protective film of claim 1, wherein an acrylic adhesive layer is further formed on a rear surface of the urethane substrate film on which the urethane coating layer is formed. The polyurethane protective film according to claim 1, wherein the urethane substrate film contains 0.1 to 20% by weight of an inorganic sunscreen. According to claim 1, wherein the urethane coating solution is 10 to 65% by weight of polyisocyanate, polyol The polyurethane protective film, characterized in that 10 to 65% by weight, 0.1 to 20% by weight of inorganic sunscreen, 0.1 to 20% by weight of organic sunscreen and 0.1 to 2% by weight of catalyst are dispersed in an organic solvent. The polyurethane protective film according to claim 1, wherein the inorganic sunscreen is at least one selected from the group consisting of titanium dioxide, zinc oxide, manganese oxide, zirconium dioxide and cerium dioxide having an aperture of 200 nm or less. 6. The polyurethane protective film of claim 5, wherein the inorganic sunscreen is surface treated with any one selected from the group consisting of silicon, metal fatty acid and silica. According to claim 1, wherein the organic sunscreen is any one selected from the group consisting of p-aminobenzoic acid derivatives, benzylidene campo derivatives, cinnamic acid derivatives, benzophenone derivatives and benzotriazole derivatives Urethane Protective Film. The polyurethane protective film of claim 4, wherein the polyol is at least one selected from the group consisting of polycarbonate, polyester, polyacrylate, and polyacylene. 9. The polyurethane protective film of claim 8, wherein the polyol has a weight average molecular weight of 50 to 5,000. 5. The polyurethane protective film according to claim 4, wherein the polyol contains a crosslinking agent of a low molecular weight having a weight average molecular weight of 20 to 500 within 50%. Polyurethane protective film of claim 1 is applied to any one of the exterior structure selected from the group consisting of automobiles, ships and buildings.