JP7371827B2 - Vehicle exterior protective film and method for manufacturing vehicle exterior protective film - Google Patents

Description

The present disclosure relates to a vehicle exterior protective film and a method for manufacturing a vehicle exterior protective film.

For the exterior of vehicles such as automobiles, a protective film for vehicle exterior is pasted on the exterior of the vehicle, specifically on the painted surface of the exterior, in order to improve durability and prevent scratches. is protected. A vehicle exterior protective film is attached in a finishing process during vehicle manufacturing, and is placed on the outermost surface of the vehicle exterior. In addition, vehicle users may apply protective films to their vehicles by themselves in order to prevent damage to frequently used parts such as door handles.
Furthermore, in order to prevent the completed vehicle from being damaged during transportation, a vehicle exterior protective film may be attached to the wheels and the like.

A vehicle exterior protective film (hereinafter sometimes simply referred to as a "protective film") is required to have stretchability that allows it to easily follow the curve of the exterior surface of a vehicle when it is pasted. In addition, the protective film has flexibility to prevent scratches caused by contact with particles such as sand, scratch resistance when external frictional force is applied, high transparency that does not spoil the appearance of the vehicle itself, and long-term exposure to outside air. Weather resistance and durability are required to withstand applications exposed to high temperatures.
The protective film is made of urethane resin that is flexible and has good stretchability, and has a surface layer formed by urethane coating on the surface of the polyurethane film protective layer, that is, the outer surface, so that the polyurethane film does not come into contact with the vehicle. A layered structure having an adhesive layer on the side facing the adhesive is common, and commercially available products are also known.

Various types of protective films have been proposed to be attached to the exterior of a vehicle.
For example, a protective adhesive tape has been proposed that has chipping resistance and weather resistance and has as a base material a mixture of a urethane polymer and an acrylic polymer consisting of two or more types of acrylic monomers having a specific glass transition temperature. (See Patent Document 1).
Further, the curved portion of the surface to be protected is provided with a first layer containing specific amounts of polypropylene resin and polyethylene resin, and a second layer containing polyethylene resin and an ultraviolet absorber, and further has an adhesive layer. A surface protection film has been proposed that has excellent adhesion, moderate lubricity, and excellent transparency and weather resistance (see, for example, Patent Document 2).

Japanese Patent Application Publication No. 2010-95560 Japanese Patent Application Publication No. 2013-173355

However, the urethane resin contained in commonly used protective films is susceptible to deterioration due to ultraviolet rays, and over time, the protective properties decrease due to discoloration caused by ultraviolet rays and cracking due to embrittlement, which affects the appearance. I have something to give. Furthermore, the surface layer produced by coating has poor stretchability.
In the technique described in Patent Document 1, since the base material still contains a urethane polymer, there is still room for improvement in weather resistance in vehicle exterior applications used under severe conditions.
In addition, the technology described in Patent Document 2 is intended for temporary protection such as when transporting a vehicle, and its transparency is not sufficient from the viewpoint of not affecting the appearance of the vehicle, and it is not transparent enough for a long period of time. No consideration has been given to the durability required for application as a protective film for the exterior of a vehicle.

As described above, the protective film in the present disclosure is a film that is attached as a finishing material to the surface of a completed vehicle such as an automobile using an adhesive layer. It is also a protective film that can be applied by car owners themselves to improve the scratch resistance of the car surface, depending on the purpose. In this respect, the usage mode is completely different from the synthetic resin skin material used as a decorative film for the interior of a vehicle, which is placed on the surface of a resin molded body and fixed by heating and press-bonding to the surface of the resin molded body by heat molding. It's a different film.

An object of an embodiment of the present invention is to provide a protective film for the exterior of a vehicle that has excellent weather resistance, good molding stretchability and surface scratch resistance, and can protect the exterior of a vehicle for a long period of time. .
Another object of the present invention is to provide a method for producing a protective film for vehicle exteriors that has excellent weather resistance, good molding stretchability, and good surface scratch resistance.

Means for solving the problem include the following embodiments.
<1> A base material layer containing a thermoplastic resin that does not have a urethane bond in its molecules and has a softening point in the range of 40°C to 150°C; 20% or less, using a Sunshine carbon arc lamp type weather resistance tester, irradiance: 78.5 W/m ² , surface spray, black panel temperature (hereinafter sometimes referred to as BPT): 63°C ± A skin layer with a haze variation of 50% or less before and after conducting the test for 3000 hours under the conditions of 3°C, humidity: 50 ± 5% RH, and the base layer, provided on the opposite side of the skin layer. A protective film for a vehicle exterior, comprising an adhesive layer and a protective sheet provided on the opposite side of the adhesive layer to the base layer.

<2> The vehicle exterior protective film according to <1>, wherein the skin layer contains at least one selected from the group consisting of an acrylic resin and a fluororesin.
<3> The fluororesin is trifluorochloroethylene-vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer The protective film for vehicle exterior according to <2>, which contains at least one fluororesin selected from the group consisting of fluororesin.

<4> The thermoplastic resin includes at least one selected from the group consisting of acrylic resin, vinyl chloride resin, and acrylonitrile/butadiene/styrene copolymer according to any one of <1> to <3>. A protective film for vehicle exteriors.
<5> The vehicle exterior protective film according to any one of <1> to <4>, wherein the base layer contains a colorant.
<6> The vehicle exterior protection according to any one of <1> to <5>, which has a primer layer between the base material layer and the adhesive layer, and the primer layer contains an acrylic resin. film.

<7> A step of forming a base material layer using a thermoplastic resin that does not have a urethane bond in its molecules and has a softening point in the range of 40°C to 150°C, and a step of forming a base material layer on one surface of the base material layer. , haze is 20% or less, irradiance: 78.5 W/m ² , surface spray applied, BPT: 63°C ± 3°C, humidity: 50 ± 5% using a Sunshine carbon arc lamp type weather resistance tester. A step of forming a skin layer whose haze varies by 50% or less before and after conducting a test for 3000 hours under RH conditions, and applying an adhesive to the opposite side of the base layer from the skin layer. forming an adhesive layer; and pasting a protective sheet having a release layer on the opposite side of the adhesive layer from the base layer, with the adhesive layer and the release layer in contact with each other. A method for manufacturing a protective film for vehicle exterior.

<8> The step of forming the skin layer includes the step of bringing the pre-formed skin layer into contact with the base material layer and heat-pressing the skin layer and the base material layer with a pair of rolls. <7> A method for producing a protective film for vehicle exterior as described in .
<9> One of the pair of rolls is a embossed roll having a embossed pattern, the embossed roll is brought into contact with the skin layer side, the skin layer and the base material layer are bonded by heat and pressure, and the base material layer of the skin layer is The method for manufacturing a vehicle exterior protective film according to <8>, wherein a grain pattern is formed on the surface opposite to the side in contact with the surface.

According to one embodiment of the present invention, it is possible to provide a vehicle exterior protective film that has excellent weather resistance, good molding stretchability and surface scratch resistance, and can protect the vehicle exterior for a long period of time. .
Further, according to another embodiment of the present invention, it is possible to provide a method for producing a protective film for a vehicle exterior that has excellent weather resistance, good molding stretchability, and good surface scratch resistance.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the vehicle exterior protective film of the present disclosure.

Hereinafter, the vehicle exterior protective film of the present disclosure and the method for manufacturing the vehicle exterior protective film will be described in detail.
Although the description of the constituent elements described below may be made based on typical embodiments of the present disclosure, the present disclosure is not limited to such embodiments.
In the present disclosure, "~" indicating a numerical range is used to include the numerical values written before and after it as a lower limit value and an upper limit value.
In the numerical ranges described step by step in this disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another numerical range described step by step. . Furthermore, in the numerical ranges described in this disclosure, the upper limit or lower limit of the numerical range may be replaced with the values shown in the Examples.
In this disclosure, combinations of preferred aspects are more preferred aspects.
In the present disclosure, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition. means.
In the present disclosure, the term "step" is used not only to refer to an independent step but also to include the term "step" even if the step cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.

A "layer containing a resin" in the present disclosure refers to a "layer formed containing a resin that is the main component of the layer". That is, a "layer containing resin" in the present disclosure refers to a resin layer containing only a resin, and a resin composition that further contains optional components such as a plasticizer, a colorant, and an ultraviolet absorber in addition to the resin as a main component. It is used in a meaning that includes both formed layers.
In addition, the "resin which is a main component" in this indication refers to the resin contained 60 mass % or more with respect to the total amount of the resin composition in which the said component is contained.
Hereinafter, in this disclosure, polyvinyl chloride resin may be referred to as PVC resin. Further, a resin containing a structural unit derived from at least one of an acrylic acid monomer and a methacrylic acid monomer is sometimes referred to as an acrylic resin. Further, an acrylonitrile/butadiene/styrene copolymer is sometimes referred to as an ABS resin.

The vehicle exterior protective film of the present disclosure has a haze of 20% or less as a skin layer and has excellent transparency, and is measured using a Sunshine carbon arc lamp type weather resistance tester, and has an irradiance of irradiance as exposure energy: 78.5 W/m ² , black panel temperature (BPT): 63°C ± 3°C, humidity: 50 ± 5% RH, and a test was conducted for 3000 hours with surface spray assuming rain. The change in haze before and after is 50% or less, and the layer has excellent weather resistance and suppresses a decrease in transparency even after the weather resistance test, so the protection of the base layer is good.
In the present disclosure, a test that combines the evaluation of rain resistance and light resistance, in which exposure is performed under conditions with surface spray assuming rain, may be referred to as a "weather resistance test."
Further, the base material layer is formed using a thermoplastic resin that does not have urethane bonds in its molecules, and has good weather resistance. Furthermore, since the softening point of the thermoplastic resin contained in the base material layer is in the range of 40°C to 150°C, the base material layer has flexibility, impact resistance, and stretchability when applied to the exterior of a vehicle. It is thought that it will be good.
Therefore, even when the protective film for vehicle exterior of the present disclosure is peeled off and attached to the exterior of the vehicle via the adhesive surface, it can be easily attached by following the shape of the vehicle. After that, the functions of the transparent skin layer with good scratch resistance and the flexible base material layer can protect, for example, the painted surface of the vehicle for a long period of time.
Here, when the formed base material layer is a transparent layer with a haze of 20% or less, the vehicle exterior protective film of the present disclosure can be used without affecting the hue and texture of the painted surface of the vehicle. The surface can be effectively protected.
In addition, by incorporating a coloring agent into the base material layer or forming a grain pattern on the surface layer, various designs can be added to the vehicle exterior while protecting the vehicle exterior for a long period of time. It also has the advantage of being able to

The vehicle exterior protective film of the present disclosure includes a skin layer, a base material layer, an adhesive layer, and a protective sheet in this order, and the protective sheet is peeled off and the skin layer and base material layer are applied to the painted surface of the vehicle via the adhesive layer. The laminate can be stably and firmly fixed.

Hereinafter, preferred embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments.

<Protective film for vehicle exterior>
The vehicle exterior protective film of the present disclosure contains a thermoplastic resin (hereinafter sometimes referred to as a specific thermoplastic resin) that does not have a urethane bond in its molecules and has a softening point in the range of 40°C to 150°C. A base material layer, provided on one surface of the base material layer, haze is 20% or less, irradiance: 78.5 W/m ² using a Sunshine carbon arc lamp type weather resistance tester, surface With spraying, black panel temperature: 63 ° C ± 3 ° C, humidity: 50 ± 5% RH The skin layer has a haze variation of 50% or less before and after conducting the test for 3000 hours, and the base material layer. The device includes an adhesive layer provided on a side opposite to the skin layer, and a protective sheet provided on a side of the adhesive layer opposite to the base material layer.

The protective film of the present disclosure will be explained with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing one aspect of the layer structure of the protective film 10 of the present disclosure.
The protective film 10 has a base material layer (hereinafter referred to as the base material layer as appropriate) 14 containing a specific thermoplastic resin, and a haze provided on one surface thereof is 20% or less, and a sunshine carbon arc lamp type. Before and after conducting a test for 3000 hours using a weather resistance tester under the conditions of irradiance: 78.5 W/m ² , surface spray, black panel temperature: 63°C ± 3°C, humidity: 50 ± 5% RH. A skin layer (hereinafter referred to as the skin layer as appropriate) whose haze variation is 50% or less, an adhesive layer 16, and a surface of the adhesive layer 16 that is provided on the surface opposite to the surface in contact with the base material layer 14. , and a protective sheet 18 for protecting the adhesive layer 16 are provided in this order.
That is, one embodiment of the protective film 10 shown in FIG. 1 has a laminated structure including a skin layer 12, a base layer 14, an adhesive layer 16, and a protective sheet 18 in this order.
The surface of the skin layer 12 on the side opposite to the side in contact with the base material layer 14 may have an uneven pattern called a grain pattern. Since the side of the skin layer having the grain pattern is located at the outermost surface of the vehicle when the protective film 10 is placed on the exterior surface of the vehicle and pasted, it will be referred to as the side opposite to the side of the skin layer in contact with the base material layer. The side surface is sometimes referred to as the "surface." By forming a grain pattern on the surface of the skin layer, it is possible to give a distinctive design to the exterior of the vehicle that cannot be achieved with a painted surface.

Hereinafter, the vehicle exterior protective film will be sequentially explained along with the materials constituting it and its manufacturing method.
(1. Base material layer)
The base material layer contains a specific thermoplastic resin. The specific thermoplastic resin that can be used for the base layer is not particularly limited as long as it has the physical properties described above. In other words, in consideration of various conditions such as stretchability and weather resistance when applied to the exterior of a vehicle, we made a material from a known thermoplastic resin that does not have urethane bonds in its molecules and has stretchability and impact resistance. From this viewpoint, a thermoplastic resin having a softening point in the range of 40°C to 150°C is selected and used.

Specific thermoplastic resins that can be used for the base layer include, for example, polyethylene (PE), polypropylene (PP), PVC resin, polystyrene (PS), polyvinyl acetate (PVAc), ABS resin, and acrylonitrile/styrene copolymer. (AS resin), acrylic resins such as polymethyl methacrylate (PMMA), and fluororesins such as polytetrafluoroethylene (PTFE).
Among them, from the viewpoint of better weather resistance and impact resistance when attached to the exterior of a vehicle, the specific thermoplastic resins contained in the base material layer include acrylic resin, PVC resin, and ABS resin. Preferably, acrylic resin and PVC resin are more preferable.

(acrylic resin)
Specifically, the acrylic resin includes, for example, a polymer or copolymer of methacrylic acid or methacrylic acid ester represented by polymethyl methacrylate (PMMA), a copolymer of alkyl methacrylate, alkyl acrylate, and styrene, etc. From the viewpoint of good stretchability, mixtures of copolymers of alkyl methacrylate, alkyl acrylate, and styrene and copolymers of methyl methacrylate and methyl acrylate are preferred.

The acrylic resin that can be used for the base material layer has excellent weather resistance, stretchability, and flexibility, and has good adhesion to other resin layers provided adjacently. Therefore, by including the acrylic resin in the base layer, even when the protective film is stretched and pasted on the outside surface of the vehicle, it can be pasted while following the outside surface of the vehicle, and breakage during stretching is suppressed. . Furthermore, since it is difficult to discolor even when heated, the attached protective film maintains high transparency in combination with the function of the skin layer, and maintains the appearance of the vehicle at a good level for a long period of time. This has the secondary effect of being able to.
In addition, since acrylic resin has good transparency, it is possible to add colorants to the acrylic resin as described below, or add light-scattering colorants such as pigments with metallic luster or pearl pigments. , it is possible to arbitrarily give the vehicle a desired good hue, a design with excellent gloss, etc.

(PVC resin)
The PVC resin that can be used for the base layer is not particularly limited, and any known film-forming PVC resin can be appropriately selected and used.

(ABS resin)
The ABS resin that can be used for the base material layer is not particularly limited, and any known film-forming ABS resin can be appropriately selected and used. The copolymerization ratio of acrylonitrile, butadiene, and styrene in the ABS resin can also be arbitrarily determined depending on the purpose.
When the base material layer contains ABS resin, the ABS resin may be used alone or as a resin mixture mixed with AS resin, polycarbonate (PC), polypropylene (PP), etc.
When ABS resin is used as the resin in the base material layer, it is preferable to use the ABS resin alone or to use a resin mixture of PC and ABS resin (PC/ABS), and it is more preferable to use the ABS resin alone. preferable.
When using ABS resin as the resin in the base material layer, only one type of ABS resin may be used, or two or more types of ABS resins having different copolymerization ratios may be used in combination.

The base material layer may contain only one type of specific thermoplastic resin, or may contain two or more types of specific thermoplastic resin.

In addition to the specific thermoplastic resin described above, the base material layer may also contain various components other than the specific thermoplastic resin. Other components that the base layer may contain include thermoplastic resins other than the specific thermoplastic resin, colorants, plasticizers, fillers, lubricants, processing aids, stabilizers, and the like.

The base layer can contain a colorant as another component.
Since the base material layer contains a coloring agent, a desired hue can be imparted to the protective film, and by attaching the protective film to a vehicle, various designs can be imparted to the exterior of the vehicle.

When the base material layer contains a colorant, the colorant is not particularly limited, and dyes, pigments, etc. can be appropriately selected and used.
Colorants include inorganic pigments such as titanium white (titanium dioxide), zinc white, ultramarine, cobalt blue, Bengara, vermilion, yellow lead, titanium yellow, carbon black, quinacridone, permanent red 4R, isoindolinone, and Hansa yellow. A, organic pigments or dyes such as phthalocyanine blue, industhrene blue RS, and aniline black; metal pigments selected from the group consisting of foil powders of metals such as aluminum and brass; foil powders of titanium dioxide-coated mica and basic lead carbonate; Examples include pearlescent pigments selected from the group consisting of: Among these, colorants such as titanium white are more preferred from the viewpoint of weather resistance.
Further, the base layer may contain extender pigments (fillers) such as calcium carbonate, silica (silicon dioxide), alumina (aluminum oxide), barium sulfate, etc., if necessary.

When the base material layer contains a coloring agent, it may contain only one kind of coloring agent, or it may contain two or more kinds for the purpose of toning.
There are no particular restrictions on the type and content of the coloring agent in the resin composition used to form the base layer, and the coloring used may vary depending on the desired hue of the synthetic resin skin material, the hiding power of the molded base material, etc. The type and content of the agent may be selected as appropriate.
When the base layer contains a colorant, the general content of the colorant is more than 0% by mass and 20% by mass or less based on the total solid content of the resin composition constituting the base layer. It is preferably 1% by mass to 10% by mass. Note that the solid content herein refers to the total amount of components excluding the solvent among all components of the resin composition constituting the base layer.

The thickness of the base material layer is preferably in the range of 50 μm to 300 μm, more preferably in the range of 100 μm to 250 μm. By having a thickness within the above range, even if it is stretched when pasted on the outside surface of a vehicle, breakage is effectively suppressed, and it has appropriate cushioning properties and flexibility, so by pasting the protective film, The scratch resistance of the vehicle is improved.
The thickness of the base layer and the thickness of each layer in the protective film described below can be measured by observing a cut surface of the protective film cut perpendicularly to the surface direction. Therefore, the film thickness of each layer in the protective film in the present disclosure refers to the film thickness after drying.

There is no particular restriction on the method of forming the base material layer, and known sheet forming methods such as extrusion, calendering, and casting can be applied.
Among these, the calender method is preferred in terms of ease of production and easy maintenance of the apparatus. In particular, when the base material layer contains a colorant, the softened resin and solid colorant can be supplied to a calendar roll and formed into a sheet or film. The material layer can be easily manufactured.
Furthermore, by applying the calendering method, cleaning inside the device required when changing the type and amount of colorant added can be performed more easily than when using a molding method such as an extrusion method. Therefore, by applying the calendaring method when forming a layer containing a colorant as a base material layer, it is possible to easily manufacture various base material layers with desired hues, and small-lot production of protective films is possible. Also suitable for

(2. Epidermal layer)
The protective film of the present disclosure has a skin layer on one surface of the base layer.
The skin layer in the protective film of the present disclosure has a haze of 20% or less, and was measured using a Sunshine carbon arc lamp type weather resistance tester, irradiance: 78.5 W/m ² , with surface spray, BPT: 63°C ± The change in haze before and after conducting the test for 3000 hours at 3° C. and humidity: 50±5% RH is 50% or less.
The haze of the skin layer in the protective film can be measured according to the method described in JIS K 7136 (2000).
The haze measurement in the present disclosure is performed using a haze meter: HZ-V3 manufactured by Suga Test Instruments Co., Ltd.
In addition, with commercially available protective films, etc., it is difficult to peel off only the skin layer, so we evaluated the protective film as a laminate using the same method and measured the haze and the change in haze before and after the weather resistance test. Then, we will estimate the physical properties of the epidermal layer.

Among the weather resistance tests using the Sunshine Carbon Arc Weather-Ometer (hereinafter sometimes referred to as SWOM), the light resistance test is performed using the method described in JIS B 7753 (2004). It can be carried out according to the method.
The weather resistance test in the present disclosure was conducted using a Sunshine Carbon Arc (Open Frame Carbon Arc) lamp-type light resistance and weather resistance tester: WEL-300L manufactured by Suga Test Instruments Co., Ltd. as the SWOM, with an irradiance of 78.5 W. /m ² , with surface spray, BPT: 63°C ± 3°C, humidity: 50 ± 5% RH.
First, before the SWOM test, the haze of the epidermal layer is measured and confirmed to be 20% or less.
Thereafter, a test under the above-mentioned conditions was carried out using the SWOM tester for 3000 hours, and the haze after the test was measured in the same manner to calculate the rate of change. The test is performed on three samples, and the calculated average is used as the evaluation result.
The lower the rate of change in haze, the better the weather resistance and light resistance. In the protective film of the present disclosure, the rate of change in haze of the skin layer before and after the weather resistance test is 50% or less, preferably 40% or less.
For example, if the haze of the skin layer before the weather resistance test is 20% and the haze of the skin layer after the weather resistance test is 20%, the rate of change is 0%. On the other hand, if the haze of the epidermis layer after the weather resistance test is 25%, this means that the haze has increased by 5%, and the rate of change in haze is 25% compared to the haze of 20% before the test. When the haze after the test is 30%, the haze increases by 10%, and the rate of change in haze becomes 50%.

As the resin constituting the skin layer, it is preferable to select a resin with low haze, that is, a resin with high visible light transmittance.
As a guideline for selecting the resin used for the skin layer, a resin film with a thickness of 50 μm is formed using a single resin, and the haze measured using the resulting resin film as a test specimen is 20% or less, and One method is to select a resin whose haze change rate is 50% or less after 3000 hours of exposure using a SWOM tester under the conditions described above.

Since the skin layer is located on the outermost surface of the protective film, it is preferable that it has not only good weather resistance but also good scratch resistance.
From the viewpoint of scratch resistance, the skin layer preferably contains fluororesin, acrylic resin, polyester, etc., and has transparency, weather resistance, and molding stretchability (stretchability when manually attaching the protective film to the adherend). From the viewpoint of good performance, it is more preferable that the skin layer contains at least one selected from the group consisting of acrylic resin and fluororesin.

The fluororesin that can be used for the skin layer is not particularly limited as long as it is a resin obtained by polymerizing at least one monomer containing a fluorine atom as a polymerization component. Preferred are resins obtained by
Examples of the fluororesin include resins containing a polymeric component selected from tetrafluoroethylene, trifluorochloroethylene, vinyl fluoride, and vinylidene fluoride. More specifically, trifluorochloride, which is a homopolymer of a polymer component containing a fluorine atom such as a tetrafluoroethylene resin, a vinyl fluoride resin, or a vinylidene fluoride resin, and a copolymer containing the polymer component described above Examples include ethylene-vinylidene fluoride copolymer, vinylidene fluoride-propylene hexafluoride copolymer, and vinylidene fluoride-propylene hexafluoride-tetrafluoroethylene copolymer. Among them, from the group consisting of trifluorochloroethylene-vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer It is preferable that at least one selected fluororesin is included.

The skin layer may contain only one type of resin, or may contain two or more types of resin in combination.
When the skin layer contains two or more resins, for example, vinylidene fluoride resin, trifluorochloroethylene-vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride resin. It may be a mixture of two or more fluororesins selected from the group consisting of -6-fluorinated propylene-4-tetrafluoroethylene copolymer, and may contain an acrylic resin and a fluororesin.

When the skin layer contains two or more types of resin, it may be a mixture of two or more resins, or may have a layered structure of two or more resins.
For example, as a skin layer, the surface, that is, the outermost layer on the side opposite to the side of the protective film to be applied to the vehicle, is a layer containing a fluororesin, and the purpose is to further improve the adhesion between the skin layer and the base material layer. It is also possible to adopt an embodiment in which a layer containing an acrylic resin is provided between the layer containing a fluororesin and a base material layer, or a two-layer structure of a layer containing a fluororesin and a layer containing an acrylic resin.

The skin layer may be prepared by molding a resin onto a film using a conventional method, or a commercially available film may be used.
A commercially available film that can be used for the skin layer includes KCF film manufactured by Kureha Extech Co., Ltd. KFC film is a multilayer film having a laminated structure of a polyvinylidene fluoride layer and an acrylic resin layer.
In addition, examples of the skin layer containing an acrylic resin include Acryprene (registered trademark) manufactured by Mitsubishi Chemical Corporation. Acryprene is a film containing PMMA, and among these, a film with a laminated structure having a layer containing a photocurable acrylic resin on the surface of PMMA is preferable.

The thickness of the skin layer is preferably in the range of 5 μm to 200 μm, more preferably in the range of 10 μm to 100 μm, from the viewpoint of strength and uneven pattern retention.
When the thickness of the skin layer is within the above range, the weather resistance and scratch resistance of the surface of the protective film will be good.
In addition, the thickness of the skin layer when the skin layer has a textured pattern refers to the distance from the top of the convex part of the surface on which the textured pattern is formed to the bottom surface of the skin layer.

The skin layer may have an uneven pattern called a grain pattern on the side opposite to the surface of the skin layer on the base layer side. When the skin layer has a grain pattern, from the viewpoint of retention of the grain pattern, the thickness of the skin layer is preferably greater than the distance between the bottom of the deepest part of the concave part of the concave-convex pattern and the top of the convex part. For example, when forming an uneven pattern in which the depth of the recesses is 1 μm or less, the thickness of the skin layer can be about 5 μm, and it has shallow and deep recesses, like a natural leather-like pattern. However, when the deep recess is 2 μm to 5 μm, the thickness of the skin layer is preferably 10 μm or more.
Note that when the skin layer has a laminated structure of two or more layers as described above, the thickness of the skin layer refers to the total thickness of the plurality of layers.

(3. Adhesive layer)
The protective film has an adhesive layer on the surface of the base layer opposite to the skin layer.
The protective film is attached to the outer surface of the vehicle via an adhesive layer, and functions as an exterior material for the vehicle to suppress scratches and the like on the surface.
The adhesive layer can be formed by applying at least one of a known adhesive and a pressure-sensitive adhesive to the surface of the base material layer that is opposite to the side that contacts the skin layer.
There are no particular limitations on the adhesive used to form the adhesive layer included in the protective film. It is preferable to select an adhesive, pressure-sensitive adhesive, etc. that has good affinity with the thermoplastic resin contained in the base material layer.
As the adhesive, for example, (1) a two-component curing type polyester adhesive, (2) a two-component curing type acrylic adhesive, etc. are preferably used.
Note that the adhesive used to form the adhesive layer is also available as a commercial product, such as Olivine series [Toyo Ink Co., Ltd.], Daikarac 7250T [acrylic adhesive: Daido Kasei Kogyo Co., Ltd.] , Daikarac 7250NT [two-component curing polyester adhesive: Daido Kasei Kogyo Co., Ltd.], etc. are suitable.
The thickness of the adhesive layer is preferably in the range of 20 μm to 50 μm.

In addition, when forming an adhesive layer on the base material layer, a primer layer as detailed below is formed between the base material layer and the adhesive layer for the purpose of improving adhesion, and the surface of the formed primer layer is An adhesive layer can be formed by applying at least one of an adhesive and a pressure-sensitive adhesive.
As a method for providing an adhesive layer on the base material layer or primer layer, any known method such as a transfer method or a coating method can be used. From the viewpoint of easily forming an adhesive layer with a uniform thickness, it is preferable to use a transfer method.

(4. Protective sheet)
The protective film of the present disclosure has a protective sheet on the adhesive layer for the purpose of protecting the surface of the adhesive layer provided adjacent to the base layer.
Examples of the base material for the protective sheet include paper, resin film, and the like.
As the protective sheet, a resin film, release-treated paper, resin-laminated paper, or the like can be appropriately selected and used.
The protective sheet is peeled off when applying the protective film to the vehicle.

(5. Other layers)
In addition to the base layer, skin layer, and adhesive layer described above, the protective film may further include other layers as long as the effect is not impaired.
Examples of other layers include a primer layer, a design layer, a heat shielding layer, and an ultraviolet absorbing layer.

(Primer layer)
Between the base material layer and the adhesive layer, a resin layer as a primer layer is further bonded to the base material layer in order to further improve the adhesion between the base material layer and the adhesive layer, and between the protective film and the outer surface of the vehicle. It may be present between the layers.
The primer layer can be formed by a coating method. That is, the primer layer can be formed by dissolving the resin for forming the primer layer in an appropriate solvent, applying it to the surface of the base layer opposite to the skin layer, and drying.
The resin contained in the primer layer may be polyester resin or acrylic resin from the viewpoint of having good affinity with the thermoplastic resin contained in the base material layer and the adhesive contained in the adjoining adhesive layer. It is preferable to use a resin such as
The amount of the resin layer to be applied is not particularly limited and is appropriately selected depending on the purpose. Generally, from the viewpoint of the effect of improving adhesion, it is preferably in the range of 1 g/m ² to 5 g/m ² , more preferably in the range of 2 g/m ² to 3 g/m ² .

As for the thickness of each layer in the protective film of the present disclosure, as mentioned above, the thickness of the skin layer is preferably in the range of 5 μm to 200 μm, and the thickness of the base material layer is preferably in the range of 50 μm to 300 μm. Preferably, the thickness of the adhesive layer is in the range of 20 μm to 50 μm.
Furthermore, from the viewpoint of relative layer thickness, when the thickness of the base layer is 100, the thickness of the skin layer is preferably in the range of 10 to 150.

<Production method of protective film>
There are no particular limitations on the method for manufacturing the protective film of the present disclosure described above, and any known manufacturing method can be employed as appropriate.
Among these, it is preferable that the protective film be manufactured by the method for manufacturing a protective film of the present disclosure described in detail below.

The method for producing a protective film of the present disclosure includes a step (step (I)) of forming a base layer using a thermoplastic resin that does not have a urethane bond in its molecules and has a softening point in the range of 40°C to 150°C. ), haze is 20% or less on one side of the base material layer, irradiance: 78.5 W/m ² , surface sprayed, BPT: 63 using a Sunshine carbon arc lamp type weather resistance tester. A step (step (II)) of forming a skin layer in which the change in haze before and after conducting the test for 3000 hours under the conditions of °C ± 3 °C and humidity: 50 ± 5% RH is 50% or less (step (II)), of the base material layer, A step of applying an adhesive to form an adhesive layer on the side opposite to the skin layer (step (III)), and a protective sheet having a release layer on the side of the adhesive layer opposite to the base layer, It includes a step (step (IV)) of bringing the adhesive layer and the release layer into contact with each other and pasting them.

(Step (I))
In step (I), first, a thermoplastic resin-containing base layer is formed using a thermoplastic resin such as acrylic resin having a softening point in the range of 40° C. to 150° C.
From the viewpoint of processability, it is preferable to apply a calendering method to form the base material layer.
By forming the base material layer by a calendering method, a base material layer having a uniform thickness can be formed more easily than, for example, by an extrusion method. In addition, when adding a colorant to the base layer as desired, as mentioned above, the calendar method can be applied, making it possible to change the type and amount of colorant used in the base layer. The interior of the device can be easily cleaned.
An example of a method for forming a base material layer using an acrylic resin and a pigment as a coloring agent is to add a predetermined amount of pigment to an acrylic resin, and heat and mix the mixture at, for example, around 170° C. with a thermal mixing roll. Examples of the method include obtaining a colored acrylic resin and forming a base layer by a calendaring method using the obtained colored acrylic resin. When no colorant is used, the same procedure can be carried out except that the step of adding the pigment described above is omitted.
In addition, in step (I), components other than the pigment can also be contained in the thermoplastic resin as necessary.

(Step (II))
In step (II), haze is 20% or less on one side of the base material layer, irradiance: 78.5 W/m ² using a Sunshine carbon arc lamp type weather resistance tester, surface spraying. , black panel temperature: 63°C ± 3°C, humidity: 50 ± 5% RH A light resistance test was performed for 3000 hours to form a skin layer in which the haze variation was 50% or less before and after the exposure. Note that step (II) includes both forming a skin layer having the above physical properties and preparing a commercially available skin layer.
As mentioned above, the resin with good transparency and light resistance contained in the skin layer is preferably at least one of fluororesins and acrylic resins.
In step (II), a skin layer containing at least one selected from the group consisting of fluororesins and acrylic resins can be formed by a calendering method, an extrusion method, or the like.
When forming a skin layer having a laminated structure, a laminated film can be formed by coextruding two or more resins.
Further, step (II) includes preparing a commercially available film having the above-mentioned weather resistance and having a haze of 20% or less as a skin layer.
Thereafter, in the step of forming a skin layer on one side of the base material layer obtained in step (I), the base material layer and the skin layer are laminated and heated under pressure with a pair of rollers. Alternatively, a skin layer may be formed directly on one side of the base layer.
Further, the step (II), that is, the step of forming the skin layer, includes a step of bringing the pre-formed skin layer into contact with the base material layer and heat-pressing the skin layer and the base material layer with a pair of rolls. can be included.

(Step (III))
In step (III), an adhesive is applied to the side of the base material layer opposite to the skin layer to form an adhesive layer. In step (III), an adhesive or a pressure-sensitive adhesive may be applied to the base layer to form an adhesive layer.

(Step (IV))
In step (IV), a protective sheet having a release layer is attached to the side of the adhesive layer formed in step (III) opposite to the base layer, with the adhesive layer and the release layer in contact with each other.
In addition, as mentioned above, when an adhesive layer is formed in advance on the surface of the protective sheet, and then the formed adhesive layer and the base material layer are brought into contact and laminated, heated and pressurized, step (IV ) is included in step (III).

(Other processes)
(Process (V))
When step (II) includes the step of bringing the pre-formed skin layer into contact with the base material layer and heat-pressing the skin layer and the base material layer with a pair of rolls, one of the pair of rolls has a textured pattern. A process of bringing the shibo roll into contact with the skin layer side, heat-pressing the skin layer and the base material layer, and forming a shibo pattern on the side of the skin layer opposite to the side that contacts the base material layer. (V) may be included.

Step (V) and step (III) can be performed simultaneously. That is, the adhesive layer and the protective sheet are laminated in this order on the side of the skin layer having the base material layer to obtain a laminate, and then the laminate is embossed using a squeeze roll. It is possible to simultaneously heat and pressure bond each layer and form a desired uneven pattern on the surface of the skin layer.
In the present disclosure, laminate embossing refers to embossing using a squeeze roll on one of a pair of rolls that performs thermocompression bonding, bonding multiple resin-containing films together by thermocompression bonding, and embossing the surface of the resin-containing film in contact with the squeeze roll. Refers to forming unevenness on the surface by squeezing with a squeezing roll. In step (V), the laminate is embossed in an arrangement in which a drawing roll is located on the skin layer side and a smooth roll is located on the base material layer side. According to this method, the lamination of each layer and the formation of an uneven pattern on the surface layer can be carried out sequentially or simultaneously in one step.

By laminating and embossing multiple resin-containing films using a squeeze roll on which an arbitrary uneven pattern, such as a natural leather-like uneven pattern, has been formed on the surface of the skin layer, it can be applied to one surface of the resin-containing film. The squeezing and pressing is performed in one step, and an uneven pattern of an arbitrary design, such as natural leather-like unevenness, is transferred to the outermost surface of the skin layer of the formed protective film.
By selecting the shape of the uneven pattern formed on the drawing roll, not only a natural leather-like pattern but also a pattern having an arbitrary uneven shape can be formed on the surface of the protective film.
The heating temperature during lamination embossing is preferably 100°C to 190°C.

The protective film of the present disclosure can be manufactured by a simple method, has excellent appearance, transparency, weather resistance, and scratch resistance, and is suitably used as a protective film for vehicle exteriors. The protective film not only protects the exterior of a vehicle, but also allows various designs to be easily added to the exterior of vehicles such as automobiles and railway vehicles, and can be suitably used for vehicle exteriors for various purposes.

Hereinafter, the protective film of the present disclosure will be specifically described with reference to Examples, but the present disclosure is not limited thereto.

[Example 1]
(Production of protective film)
First, 100 kg of acrylic resin [Sumipex LG2 (trade name), Sumitomo Chemical Co., Ltd.] was heated to 170°C and molded into a sheet shape using a calendar method so that the thickness after drying was 200 μm to form a base material layer. obtained (Step (I)).
As the skin layer, KFC film FT-50Y (trade name) manufactured by Kureha Extech Co., Ltd. (a laminate of a layer containing polyvinylidene fluoride, which is a fluororesin, and a layer containing polymethyl methacrylate, which is an acrylic resin) was prepared (process (II)).
The polymethyl methacrylate-containing layer side of the skin layer and the base material layer were laminated in this order.
The obtained laminate is laminate-embossed using an embossing roll, one of which is a squeeze roll having a squeeze pattern, with the skin layer side in contact with the squeeze roll, and the surface layer is embossed onto the base material layer. A skin layer with a squeeze pattern was formed ((Step (II) + (Step (V))).The temperature conditions for laminate embossing were as follows: the surface temperature of the laminate was 170°C, and the speed was 10 m/min. .

After that, acrylic primer resin [141-1 (product name), Seiko Kasei Co., Ltd.] is applied to the surface of the base material layer opposite to the skin layer side in an amount such that the thickness after drying is 3 μm, and then dried. A resin layer (primer layer) is formed on the surface of the formed resin layer (primer layer), and an acrylic adhesive [Daikarac 7250T (product name), Daido Kasei Kogyo Co., Ltd.] is applied to the surface of the formed resin layer (primer layer) so that the film thickness after drying is An adhesive layer was formed by coating in an amount of 40 μm (step (III)).
Furthermore, an adhesive protective layer (protective sheet: H0SBK0A (product name), Fujiko Co., Ltd.) made of polypropylene (PP) resin with a thickness of 60 μm was provided, and a skin layer (thickness of 30 μm), a base material layer (thickness of 200 μm), A protective film including a resin layer (primer layer: 3 μm thick), an adhesive layer (40 μm thick), and a protective sheet (60 μm thick) in this order was produced (Step (IV)).

[Evaluation of protective film]
(1. Appearance (transparency))
Regarding the haze of the skin layer in the protective film, the haze of the skin layer alone (before lamination with the base material layer) was determined according to the method described in JIS K 7136 (2000), manufactured by Suga Test Instruments Co., Ltd. It was measured using a meter: HZ-V3 and evaluated based on the following criteria. Rank A and rank B are levels that pose no practical problems.
-Evaluation criteria-
A: Less than 20% B: More than 20% and less than 40% C: More than 40%

(2. Weather resistance)
The haze of the skin layer of the protective film was measured in advance according to the evaluation method of "1. Appearance (transparency)" described above.
Next, regarding the weather resistance of the skin layer in the protective film, the weather resistance of the skin layer alone (before lamination with the base material layer) was determined using the Suga Test Machine as a SWOM according to the method described in JIS B 7753 (2004). Using Sunshine Carbon Arc (Open Frame Carbon Arc) light resistance and weather resistance tester: WEL-300L manufactured by Co., Ltd., irradiance: 78.5 W/m2, with surface spray, BPT: 63°C ± 3 ℃, humidity: 50 ± 5% RH, the test was conducted under the above conditions using the above SWOM tester for 3000 hours, and the rate of change in haze was evaluated according to the evaluation method of "1. Appearance (transparency)" described above. evaluated.
The haze of the epidermis layer before the weather resistance test was compared with the haze after the weather resistance test, and the rate of change in haze was evaluated using the following criteria. Rank A and rank B are levels that pose no practical problems.
-Evaluation criteria-
A: Less than 50% B: More than 50% and less than 80% C: More than 80%

(3. Scratch resistance)
Using a Gakushin type friction testing machine specified in JIS L0823 (friction testing machine for color fastness testing) (1971), a friction test was conducted with white cotton cloth at a load of 500g, and the presence or absence of wear was visually observed after 30 reciprocations. was confirmed and evaluated using the following criteria. Rank A and rank B are levels that pose no practical problems.
-Evaluation criteria-
A: No scratches B: Slight scratches C: Obvious scratches

(4. Molding stretchability (stretchability when applied by hand))
When the obtained protective film was applied to a curved automobile bumper (area: approximately 1 m ² ) while being stretched by hand, the presence or absence of wrinkles in the protective film after stretching and application was visually observed. It was confirmed and evaluated based on the following criteria. Rank A and rank B are levels that pose no practical problems.
-Evaluation criteria-
A: No wrinkles occur even after 120% stretching B: No wrinkles occur even after stretching more than 110% and less than 120% C: Wrinkles occur when stretched 110%

(5. Impact resistance)
Using a DuPont drop impact tester specified in JIS K5600-5-3 (general paint test method: weight drop resistance) (1999), the drop height was 50 mm, the falling weight was 300 g, and the spherical surface of the striking center tip was R = 6. .35mm, and the spherical surface R of the concave part of the pedestal was 6.35mm.The condition of the protective film after the test (presence of cracking of the film due to drop impact, and presence or absence of film peeling from the pedestal due to impact) ) was visually confirmed and evaluated using the following criteria. Rank A and rank B are levels that pose no practical problems.
-Evaluation criteria-
A: No cracks, no peeling B: There are cracks, no peeling C: There are cracks, no peeling

[Example 2]
Example 2 was carried out in the same manner as in Example 1, except that the resin of the base material layer was changed to PVC resin, the base material layer was formed according to the following procedure, and the obtained PVC resin base material layer was used. A protective film was manufactured. The obtained protective film of Example 2 was evaluated in the same manner as in Example 1.
A base material layer was obtained by heating 100 kg of PVC resin [S1008C (trade name), Kaneka Corporation] to 170°C and molding it into a sheet shape using a calendar method so that the thickness after drying would be 200 μm (step (I)).

[Example 3]
Example was carried out in the same manner as in Example 1, except that the resin of the base material layer was changed to ABS resin, the base material layer was formed according to the following procedure, and the obtained base material layer made of ABS resin was used. A protective film of No. 3 was manufactured. The obtained protective film of Example 3 was evaluated in the same manner as in Example 1.
A base material layer was formed by heating 100 kg of ABS resin [TM-30G6 (trade name), UMG-ABS Co., Ltd.] to 170°C and molding it into a sheet shape using a calendar method so that the thickness after drying would be 200 μm. obtained (Step (I)).

[Comparative example 1]
As the protective film, 3M (registered trademark) Scratch Guard (trade name), which is a commercially available car wrapping film, was used as the film of Comparative Example 1.
The protective film of Comparative Example 1 was evaluated in the same manner as in Example 1.
In addition, commercially available products are a laminate of a skin layer and a base material layer and cannot be peeled off, so the appearance (transparency) and weather resistance cannot be evaluated based on the skin layer alone. The laminate excluding the above was evaluated as a test object.

[Comparative example 2]
In Example 1, 3 kg of pigment (PVMAF725 (trade name), Dainichiseika Kagyo Co., Ltd.) was added to 100 kg of acrylic resin [Sumipex LG2 (trade name), Sumitomo Chemical Co., Ltd.], and calendered while heating to 170°C. A base material layer was obtained by forming a sheet into a sheet having a thickness of 150 μm after drying.
Add 20 kg of plasticizer (DINP (product name), J-Plus Co., Ltd.) to 100 kg of PVC resin [TH800 (product name), Taiyo PVC Co., Ltd.], heat it to 170°C, and use a calendar method to determine the thickness after drying. A skin layer was obtained by molding into a sheet so that the thickness was 70 μm.
A protective film of Comparative Example 2 was produced in the same manner as in Example 1 except that the base layer and skin layer obtained above were used.
The obtained protective film of Comparative Example 2 was evaluated in the same manner as in Example 1.
The results are shown in Table 1 below.

From the results in Table 1, the protective film of the example has good transparency, weather resistance, scratch resistance, molding stretchability, and impact resistance, and does not break when applied to a vehicle. Since the protective properties are good, it is found that it is useful as an exterior protective film.
On the other hand, the vehicle exterior protective film of Comparative Example 1 using a resin containing urethane bonds in the skin layer and base layer had significantly poor weather resistance and had problems with transparency, and the skin layer did not meet the conditions of the present disclosure. In Comparative Example 2, which used a PVC resin without the use of PVC resin, the scratch resistance and impact resistance were significantly inferior, and there were also problems in transparency and weather resistance.

10 Vehicle exterior protective film (protective film)
12 Skin layer 14 Base material layer 16 Adhesive layer 18 Protective sheet (adhesive protective layer)

Claims (6)

At least one thermoplastic resin selected from the group consisting of vinyl chloride resin and acrylonitrile/butadiene/styrene copolymer, which does not have a urethane bond in its molecule and has a softening point in the range of 40°C to 150°C. a base layer containing no colorant ;
Provided on one surface of the base material layer, haze is 20% or less, irradiance: 78.5 W/m ² , surface sprayed, black panel using a Sunshine carbon arc lamp type weather resistance tester. The change in haze before and after conducting the test for 3000 hours under the conditions of temperature: 63°C ± 3°C and humidity: 50 ± 5% RH is 50% or less, and the difference between the layer containing fluororesin and the layer containing acrylic resin is The epidermis layer has a layered structure ,
an adhesive layer provided on the opposite side of the base layer from the skin layer;
A protective film for a vehicle exterior, comprising: a protective sheet provided on the opposite side of the adhesive layer to the base material layer. The fluororesin is composed of trifluorochloroethylene-vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer. The vehicle exterior protective film according to claim 1, comprising at least one fluororesin selected from the group consisting of: 3. The vehicle exterior protective film according to claim 1, further comprising a primer layer between the base layer and the adhesive layer, and the primer layer containing an acrylic resin. At least one thermoplastic resin selected from the group consisting of vinyl chloride resin and acrylonitrile/butadiene/styrene copolymer, which does not have a urethane bond in its molecule and has a softening point in the range of 40°C to 150°C. a step of forming a base material layer containing no colorant ;
On one side of the base layer, haze is 20% or less, irradiance: 78.5 W/m ² , surface sprayed, black panel temperature: A two-layer structure with a layer containing fluororesin and a layer containing acrylic resin , with a haze change of 50% or less before and after testing for 3000 hours at 63°C ± 3°C and humidity: 50 ± 5% RH. a step of forming an epidermal layer that is
a step of applying an adhesive to the side of the base material layer opposite to the skin layer to form an adhesive layer;
A step of attaching a protective sheet having a release layer to the side of the adhesive layer opposite to the base material layer with the adhesive layer and the release layer in contact with each other;
A method for producing a protective film for a vehicle exterior having the following. 5. The method according to claim 4 , wherein the step of forming the skin layer includes the step of bringing a pre-formed skin layer into contact with the base layer and heat-pressing the skin layer and the base layer with a pair of rolls. A method for manufacturing a protective film for vehicle exterior. One of the pair of rolls is a grained roll having a grained pattern,
According to claim 5 , the grain roll is brought into contact with the skin layer side, and the skin layer and the base material layer are bonded by heat and pressure, and a grain pattern is formed on the surface of the skin layer opposite to the side that contacts the base material layer. The method for manufacturing the vehicle exterior protective film described above.