JP2022054886A - Thermal barrier film - Google Patents

Abstract

To provide a thermal barrier film that is less prone to temperature rises due to light including ultraviolet and infrared rays such as sunlight, and has excellent weather resistance.SOLUTION: A thermal barrier film has at least a white reflection layer, the white reflection layer including at least one synthetic resin selected from the group consisting of polyvinyl chloride resin, acrylic resin and fluororesin, a white pigment, and a fluorescent brightener of 0.1 mass% to 5.0 mass% of the white reflection layer.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a heat shield film.

A heat-shielding film is used to improve the heat resistance of various molded products using synthetic resin. For example, the resin plate may warp over time due to infrared light.
A decorative sheet having a heat-shielding property for suppressing the occurrence of warpage due to infrared light has been proposed (see Patent Document 1). In the decorative sheet described in Patent Document 1, a printing layer and an overlay film layer are laminated in this order on a thermoplastic resin base material, and a polyester resin is used as a main chain between the printing layer and the overlay film layer. It has an adhesive layer made of a urethane-based adhesive and an anchor layer made of a urethane-based anchor agent having an acrylic resin as a main chain in this order. The overlay film layer of the decorative sheet contains an ultraviolet absorber, and the ultraviolet absorber is composed of only a triazine-based ultraviolet absorber, the printing layer contains a black pigment, and the black pigment is a perylene-based black pigment. It is described that when the UV absorber of the overlay film layer is only a triazine-based UV absorber, the UV shielding ability is improved, and a decorative sheet having excellent weather resistance as well as heat resistance and adhesion can be obtained.

Further, the heat shield film is composed of a resin composition containing a resin having a refractive index of less than 1.52 and a fine powder filler having a refractive index of 1.60 or more, and has an average reflectance of 80 at a wavelength of 810 nm to 2100 nm. A heat-shielding film having a percentage of% or more has been proposed (see Patent Document 2).
As the resin having a refractive index of less than 1.52, a polylactic acid-based polymer having a low refractive index is preferable, and the reflectance of the film is improved by increasing the difference in the refractive index from the fine powder filler. ing.

Japanese Unexamined Patent Publication No. 2016-165865 Japanese Unexamined Patent Publication No. 2007-88930

The decorative sheet containing an ultraviolet absorber absorbs ultraviolet rays contained in external light such as sunlight and converts them into heat to reduce the influence of the ultraviolet rays on the base material coated with the decorative sheet. However, since the ultraviolet absorber converts the energy of ultraviolet rays into heat, in the decorative sheet described in Patent Document 1, the temperature of the decorative sheet itself rises due to sunlight, and the temperature of the base material covered with the decorative sheet rises. It is feared that it will lead to.
The heat-shielding film described in Patent Document 2 is designed to increase the reflectance by using a specific resin having a specified reflectance in combination with a specific filler to increase the reflectance, but the durability of the film, particularly the weather resistance, is considered. And there is still room for improvement.

An object of the embodiment of the present invention is to provide a heat-shielding film having good weather resistance by suppressing a temperature rise due to ultraviolet rays such as sunlight and light including infrared rays.

Means for solving the problem include the following aspects.
<1> It has at least a white reflective layer, and the white reflective layer is composed of at least one synthetic resin selected from the group consisting of a polyvinyl chloride resin, an acrylic resin and a fluororesin, a white pigment, and a white reflective layer. A heat shield film containing 0.1% by mass to 5.0% by mass of a fluorescent whitening agent with respect to the total solid content.

<2> The heat-shielding film according to <1>, wherein the white reflective layer does not contain an ultraviolet absorber.
<3> The heat shield film according to <1> or <2>, wherein the synthetic resin contains at least one selected from the group consisting of a polyvinyl chloride resin and an acrylic resin.

<4> One of <1> to <3>, which has a colored transmission layer containing a synthetic resin and a colorant on one surface of the white reflective layer, and the colorant does not contain carbon black. The heat shield film described in.
<5> The heat shield film according to <4>, wherein the synthetic resin contained in the colored transparent layer contains at least one selected from the group consisting of a polyvinyl chloride resin and an acrylic resin.
<6> The heat shield film according to any one of <1> to <5>, which is a vehicle exterior material.
<7> The heat shield film according to any one of <1> to <5>, which is an exterior material of a building.

According to one embodiment of the present invention, it is possible to provide a heat shield film having good weather resistance by suppressing a temperature rise due to ultraviolet rays such as sunlight and light including infrared rays.

It is the schematic sectional drawing which shows an example of the aspect of the heat-shielding film of this disclosure which has a colored transmission layer and a white reflection layer.

Hereinafter, the heat shield film of the present disclosure will be described in detail.
The description of the constituents described below may be based on the representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments.
In the present disclosure, "-" indicating a numerical range is used to mean that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
In the present disclosure, the amount of each component in the composition is the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. means.
In the present disclosure, the term "process" is included in this term not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes.

In the present disclosure, the front surface of the heat-shielding film refers to the incident side of light such as sunlight for which the heat-shielding film is intended to shield heat, and the back surface of the heat-shielding film is the surface opposite to the incident side of light. Point to. When the heat shield film is used by being attached to the surface of the protected object, the side where the heat shield film comes into contact with the protected object to be protected is referred to as the back surface, and the heat shield film comes into contact with the protected object. The surface opposite to the side may be referred to as the surface.
The "layer containing a resin" in the present disclosure refers to a "layer formed containing a resin which is the main component of the layer". Here, the "resin as the main component" refers to a resin contained in an amount of 60% by mass or more with respect to the total amount of the resin composition containing the component. In the present disclosure, the resin which is the main component constituting the layer is also referred to as "main agent resin".
In the present disclosure, the "total solid content" of a composition means the total mass of all the components of the composition excluding the solvent. When the composition contains a liquid component such as a polymerizable monomer, the liquid component is contained in the solid content.

[Heat shield film]
The heat-shielding film of the present disclosure has at least a white reflective layer, and the white reflective layer comprises at least one synthetic resin selected from the group consisting of a polyvinyl chloride resin, an acrylic resin and a fluororesin, and a white pigment. , 0.1% by mass to 5.0% by mass of a fluorescent whitening agent with respect to the total solid content of the white reflective layer.
The heat-shielding film of the present disclosure contains a predetermined amount of a fluorescent whitening agent in addition to the white pigment, so that the reflectivity of ultraviolet rays is improved and the heat-shielding is improved without using an ultraviolet absorber that may generate heat due to light reception. It is possible to suppress heat generation and accumulation of generated heat due to light reception of the thermal film.

(White reflective layer)
The heat shield film of the present disclosure has at least one white reflective layer.
The white reflective layer in the present disclosure refers to a layer that is visually white and has a reflectance of light having a wavelength of 260 nm to 2500 nm of 80% or more.
The light reflectance is measured at a wavelength of 260 nm to 2500 nm using an integrating sphere spectrophotometer (for example, V-670, manufactured by Nippon Kogaku Co., Ltd.) in accordance with the method described in JIS A 5759 (2008). The light reflectance of the white reflective layer can be measured as the diffuse reflectance.
The heat shield film may have two or more white reflective layers.
The white reflective layer includes at least one synthetic resin selected from the group consisting of a polyvinyl chloride resin, an acrylic resin and a fluororesin, a white pigment, and 0.1% by mass or more based on the total solid content of the white reflective layer. Contains 5.0% by mass of optical brightener.

-At least one synthetic resin selected from the group consisting of polyvinyl chloride resin, acrylic resin and fluororesin-
The white reflective layer contains at least one synthetic resin (hereinafter, also referred to as a specific resin) selected from the group consisting of polyvinyl chloride resin, acrylic resin and fluororesin. Since the polyvinyl chloride resin, the acrylic resin and the fluororesin all have good light transmittance, the effects of the white pigment and the fluorescent whitening agent contained in the white reflective layer are more favorably exhibited. Further, the synthetic resin is useful for forming a film as a film-forming base material.
Among them, from the viewpoint of better adhesiveness between different materials, it is preferable that the synthetic resin contained in the white reflective layer contains at least one selected from the group consisting of polyvinyl chloride resin and acrylic resin.

The heat-shielding film of the present disclosure may be used as a single film, or may be used by being attached to a base material as an exterior of a vehicle, an exterior of a building, etc., and from such a viewpoint, it is different as a synthetic resin. It is preferable that the material adhesiveness is good.
Further, the polyvinyl chloride resin and the acrylic resin are general-purpose resins and have advantages such as good processability, easy availability, and low price.

The polyvinyl chloride resin can be used without particular limitation as long as the film forming property is good. Specifically, for example, a vinyl chloride homopolymer having an average degree of polymerization of 650 to 2000, preferably an average degree of polymerization of about 650 to 1800, vinyl chloride as a main material, ethylene, vinyl acetate, and methacrylic. Examples thereof include a copolymer with an acid ester and the like.
Further, a vinyl chloride homopolymer, a copolymer containing vinyl chloride, a polyester resin, an epoxy resin, an acrylic resin, a vinyl acetate resin, a urethane resin, an acrylonitrile, a styrene-butadiene copolymer resin, a partially saponified vinyl alcohol, etc. A mixed resin or the like can be used.

Specific examples of the acrylic resin include, for example, a homopolymer or copolymer of methacrylic acid or methacrylic acid ester represented by polymethylmethacrylate (PMMA), and the co-weight of alkyl methacrylate, alkyl acrylate, and styrene. Coalescence etc. can be mentioned.
Acrylic resin is excellent in weather resistance, stretchability and flexibility, and has good adhesiveness to different materials. Therefore, since the white reflective layer contains an acrylic resin, good shape follow-up can be expected even when the heat shield film is attached to the base material as an exterior material of a vehicle or a building. Further, the acrylic resin has an advantage that it is hard to discolor even when heated.

The fluororesin is not particularly limited as long as it is a resin obtained by polymerizing at least one kind of a monomer containing a fluorine atom as a polymerization component, but a resin obtained by polymerizing an olefin containing a fluorine atom can be used. preferable. Examples of the fluororesin include a resin composed of a polymerization component selected from ethylene tetrafluoride, ethylene trifluoride, vinyl fluoride, and vinylidene fluoride.
More specifically, a homopolymer of a polymerization component containing a fluorine atom such as a tetrafluorinated ethylene resin, a vinyl fluoride resin, and a vinylidene fluoride resin, and a copolymer containing the above-mentioned polymerization component, trifluoride chloride. Examples thereof include ethylene-vinylidene fluoride copolymer, vinylidene fluoride-6 propylene fluoride copolymer, vinylidene fluoride-6 propylene fluoride-4 ethylene fluoride copolymer and the like.

The synthetic resin contained in the white reflective layer may be only one kind or two or more kinds.
When the white reflective layer contains two or more kinds of synthetic resins, they may be made of different kinds of synthetic resins, or they may be made of the same kind of resins but have different degrees of polymerization, and may contain a copolymerization component derived from the same monomer. Synthetic resins with different values may be used.

-White pigment-
The white reflective layer contains a white pigment. When the white reflective layer contains a white pigment, the infrared reflectivity is improved, and the heat storage action of the white reflective layer and the heat storage action of the heat shield film having the white reflective layer can be suppressed.
The white pigment is not particularly limited, and any pigment that has good infrared reflectivity and looks white visually can be used.
White pigments include titanium oxide (also called titanium white and titanium white), barium titanate, zinc oxide (also called zinc oxide), basic lead carbonate (also called white lead), basic lead sulfate, zinc sulfide, and lithopone. (Mixed mixture of barium sulfate and zinc sulfide), Titanox (trade name: titanium dioxide particles manufactured by Kronos) and the like can be mentioned. Of these, titanium oxide or the like is preferable from the viewpoint of having better light reflectivity.

The particle size of the white pigment is preferably in the range of 0.05 μm to 10 μm in average particle size.
When the particle size of the white pigment is in the above range, the light reflectivity is good and a uniform white reflective layer is easily formed, which is preferable.
The average particle size of the white pigment can be obtained by photographing the white pigment with an electron microscope, randomly selecting 50 white pigments existing in the viewing angle, and arithmetically averaging the results of measuring the particle size. .. If the pigment is not spherical, the maximum diameter of the particles is measured.
Regarding the average particle size of the white pigment, if the average particle size of the white pigment to be used is specified in the catalog value, the catalog value is adopted.

The white reflective layer may contain only one type of white pigment or may contain two or more types of white pigment.
The content of the white pigment is preferably in the range of 1% by mass to 30% by mass with respect to the total solid content of the white reflective layer from the viewpoint of improving the light reflectivity of the heat shield film, and is preferably 2% by mass. It is more preferably in the range of% to 20% by mass, further preferably in the range of 3% by mass to 10% by mass.

-Optical brightener-
The white reflective layer contains an optical brightener. When the white reflective layer contains a fluorescent whitening agent, the white reflective layer effectively reflects ultraviolet rays and can suppress the heat storage action of the heat shield film. The present inventor believes that the fluorescent whitening agent replaces the ultraviolet absorber and plays a role as an ultraviolet stabilizer in a heat shield film.
The fluorescent whitening agent refers to an organic compound that absorbs ultraviolet rays and emits fluorescence, specifically, an organic compound that absorbs ultraviolet rays and emits pale light visually.
Examples of the fluorescent whitening agent include stilbene derivatives such as bis (triazinylamide) stilbene disulfonic acid derivatives, benzoimidazole derivatives, coumarin derivatives, aminocoumarin derivatives, benzoxazole derivatives and the like. Among them, a bis (triazinylamide) stilbene disulfonic acid derivative or the like is preferable from the viewpoint of better suppressing the heat storage action.

The white reflective layer may contain only one type of fluorescent whitening agent, or may contain two or more types of fluorescent whitening agent.
The content of the fluorescent whitening agent is preferably in the range of 0.1% by mass to 6.0% by mass with respect to the total solid content of the white reflective layer, and the effect of suppressing the heat storage action of the heat shield film is further improved. From the viewpoint, it is more preferably in the range of 0.5% by mass to 5.0% by mass, and further preferably in the range of 1.0% by mass to 5.0% by mass.

The white reflective layer is obtained by preparing a composition for forming a white reflective layer containing a specific resin, a white pigment, a predetermined amount of a fluorescent whitening agent, and other additives used as desired. It can be formed by molding the forming composition into a film.
A known additive may be added to the composition for forming a white reflective layer as long as the effect is not impaired.

Additives that can be contained in the composition for forming a white reflective layer include a plasticizer, a heat-resistant stabilizer for Ba / Zn-based vinyl chloride, a heat-resistant stabilizer such as a Ba / Zn-based vinyl chloride heat-stabilizing agent, and a fatty acid ester-based lubricant. Examples thereof include lubricants, fillers, colorants, film forming aids, flame retardants and the like.
By adding a known flame retardant such as a phosphorus-based, halogen-based, or inorganic metal-based composition to the composition for forming a white reflective layer, the flame retardancy of the white reflective layer can be improved. When a polyvinyl chloride resin is used as the specific resin, the processability and the feel of the obtained white reflective layer are further improved by adding a plasticizer.

The white reflective layer according to the present disclosure is excellent in heat shielding property and protective property of the base material when used by being attached to the base material, and therefore, it is not necessary to contain an ultraviolet absorber in particular.
The white reflective layer can contain an ultraviolet absorber. However, when the obtained white reflective layer contains an ultraviolet absorber, when the white reflective layer is irradiated with light, especially ultraviolet rays, the ultraviolet absorber converts the energy of the ultraviolet rays into heat, and the temperature of the white reflective layer rises. May rise. Therefore, from the viewpoint of the heat shielding effect, it is preferable that the white reflective layer does not contain an ultraviolet absorber.

The method for forming the white reflective layer is not particularly limited, and any known film forming method can be applied as long as the white reflective layer can be formed into a sheet.
In order to form a white reflective layer, first, a composition for forming a white reflective layer containing a synthetic resin, a white pigment, a fluorescent whitening agent, and other additives contained if desired is prepared. The obtained composition for forming a white reflective layer may be formed into a sheet.
The composition for forming a white reflective layer used for forming the white reflective layer may be prepared by dissolving a synthetic resin in an appropriate solvent, but from the viewpoint of the uniformity of the formed white reflective layer, the synthetic resin may be used. It is preferable to heat-melt to prepare a uniform composition by melting and mixing a white pigment, a fluorescent whitening agent, an additive contained if desired, and the like. As a method for forming the white reflective layer, a method of preparing a melt-mixed composition and forming it into a sheet is preferable.
Examples of the sheet forming method include a calendar method, an extrusion method, a casting method and the like. Of these, the calendar method is preferable from the viewpoint of good workability.

The thickness of the white reflective layer is preferably 40 μm to 200 μm, more preferably 50 μm to 80 μm from the viewpoint of maintaining the strength of the film.
The heat shield film of the present disclosure has at least one white reflective layer. The heat shield film may have two or more white reflective layers. When the heat-shielding film has two or more white reflective layers, the composition of each white reflective layer may be the same or different from each other.
Even when the heat-shielding film has two or more white reflective layers, the total thickness of the plurality of white reflective layers is preferably in the above range.
The thickness of the white reflective layer and the thickness of any layer described later in the heat-shielding film, for example, the thickness of each layer such as a colored transmission layer, shall be measured by observing a cut surface obtained by cutting the heat-shielding film vertically in the plane direction. Can be done. In the present disclosure, the thicknesses of five randomly selected white reflective layers on the cut surface are measured, and the arithmetic mean value is taken as the thickness of the white reflective layer. The thickness of the other layers can be measured in the same manner.

(Colored transparent layer)
The heat-shielding film of the present disclosure preferably has a colored transmission layer containing a synthetic resin and a colorant on one surface of the white reflective layer, and the colorant does not contain carbon black.
The colored transparent layer can be provided to impart a hue to the heat-shielding film and improve the design. The colored transparent layer is a colored colored layer containing a colorant, and the colored transparent layer included in the heat-shielding film of the present disclosure does not visually include the colorless layer.
The colored transparent layer is preferably a layer in which the presence of the white reflective layer cannot be visually recognized via the colored transparent layer when the heat shield film is visually recognized from the side having the colored transparent layer.
From the viewpoint of not impairing the effect of the white reflective layer, the colored transmissive layer is preferably a layer that transmits light in the infrared region and the ultraviolet region in which the white reflective layer reflects and suppresses the heat storage action.
Therefore, the colored transparent layer may be a dark color layer such as black, and the white reflective layer may not be visible through the colored transparent layer. That is, the colored transmissive layer may be a layer having a low light transmittance in the visible light region, but is preferably a layer capable of transmitting light in the infrared region and the ultraviolet region.

From the viewpoint of sufficiently obtaining the effect of the white reflective layer, the light transmittance of the colored transmittance layer is 45% or more for both infrared light having a wavelength of 780 nm to 2500 nm and ultraviolet light having a wavelength of 260 nm to 380 nm. It is preferable, and it is more preferable that the light transmittance of each of the above wavelengths is 50% or more.
The light transmittance of the colored transmissive layer can be measured using, for example, an ultraviolet-visible-infrared spectrophotometer (model number: UV-3100PC, manufactured by Shimadzu Corporation). The light transmittance in the range of each of the above wavelength ranges can be measured in increments of 10 nm, and the average value of the measurement results of the transmittance can be used as the average transmittance in the wavelength range.

FIG. 1 is a schematic cross-sectional view showing an example of an aspect of the heat shield film of the present disclosure having a colored transparent layer and a white reflective layer. The heat shield film 10 shown in FIG. 1 has a colored transmission layer 12, a white reflection layer 14, and an adhesive layer 16 in this order from the side surface that receives light. As described above, the essential layer of the heat shield film in the present disclosure is the white reflective layer 14, and the colored transparent layer 12 and the adhesive layer 16 are arbitrary layers provided as desired.
The heat-shielding film 10 shown in FIG. 1 has an adhesive layer 16 useful for adhering to a base material, and by having a colored transmission layer 12, the heat-shielding film does not impair the heat-shielding property of the white reflective layer 14. It is possible to give a hue to the appearance of 10 and give a good design.

-Synthetic resin-
The synthetic resin contained in the colored transparent layer is a resin that can be molded into a sheet shape, and the transparency of the formed sheet-shaped resin layer, that is, the transparency of infrared light, visible light, and ultraviolet light is good. Synthetic resin can be preferably used.
Examples of the synthetic resin contained in the colored transparent layer include polyvinyl chloride resin, acrylic resin, fluororesin, polyester resin, silicone resin, polyolefin resin, polystyrene elastomer, urethane resin and the like. Among them, polyvinyl chloride resin, acrylic resin, and fluororesin are preferable from the viewpoint of better transparency and weather resistance, and at least one selected from the group consisting of polyvinyl chloride resin and acrylic resin is contained. It is more preferable to do so.

The synthetic resin contained in the colored transparent layer may be the same type of resin as the synthetic resin contained in the white reflective layer described above, or may be a different type of resin. Among them, from the viewpoint of adhesion between the white reflective layer and the colored transparent layer, it is preferable to contain a synthetic resin of the same type as the synthetic resin contained in the white reflective layer.
The same type of synthetic resin is, for example, when the white reflective layer contains a polyvinyl chloride resin, the colored transparent layer also contains a polyvinyl chloride resin, and when the white reflective layer contains an acrylic resin, the colored transparent layer also contains an acrylic resin. For example. The synthetic resin of the same type is not necessarily limited to the resin having the same composition, and the resins containing the same structural unit as the structural unit constituting the main skeleton, the resin containing the same structural unit as the copolymerization component, and the like are also the same type. Included in the resin of.

-Colorant-
The colored transparent layer contains a colorant. When the colored transparent layer contains a colorant, an arbitrary hue can be imparted to the heat-shielding film.
As the colorant, a known colorant can be appropriately used depending on the desired hue. Examples of the colorant include dyes and pigments, and pigments are preferable from the viewpoint of better durability.
Coloring agents include titanium dioxide, zinc flower, ultramarine, cobalt blue, petals, vermilion, chrome yellow, titanium yellow, iron black and other inorganic pigments, quinacridone, isoindolinone, Hansa Yellow A, phthalocyanine blue, aniline black, etc. Organic pigments such as perylene black, metal pigments selected from the group consisting of metal foil powders such as aluminum and brass, pearl luster pigments selected from the group consisting of titanium dioxide-coated mica and basic lead carbonate foil powder. And so on.
When carbon black, which is a black pigment, is used, heat storage due to absorption of heat by infrared light may occur and the heat shielding property may be lowered. Therefore, the colorant in the colored transmission layer does not contain carbon black. Even if it is contained, the content of carbon black with respect to the total solid content of the colorant contained in the colored transparent layer is preferably 0.1% by mass or less, and more preferably no carbon black is contained.
When imparting a black hue to the colored transmission layer, perylene black, iron black, aniline black, or the like is used as a pigment alternative to carbon black as a colorant, or a plurality of colors having different absorption wavelengths are used. It is preferable to combine pigments to obtain a blackish hue.

The colored transparent layer may contain only one kind of colorant, or may contain two or more kinds of colorants for the purpose of achieving a desired hue or the like.
The content of the colorant in the colored transparent layer can be appropriately selected in consideration of the light transmittance and the coloring effect of the colored transparent layer. Usually, from the viewpoint of achieving both the light transmittance and the coloring effect of the colored transparent layer, it can be, for example, in the range of 0.5% by mass to 20% by mass with respect to the total solid content of the colored transparent layer. It is preferably in the range of 5% by mass to 15% by mass.

The method for forming the colored transparent layer is not particularly limited, and any known film forming method can be applied as long as the colored transparent layer can be formed into a sheet.
In order to form a colored transparent layer, first, a composition for forming a colored transparent layer containing a synthetic resin, a colorant, and other additives contained if desired is prepared, and the obtained colored transparent layer is formed. The forming composition may be formed into a sheet.
The film formation of the composition for forming a colored transparent layer can be performed in the same manner as the white reflective layer described above.
Examples of the sheet forming method include a calendar method, an extrusion method, a casting method and the like.

The thickness of the colored transparent layer is preferably 40 μm to 200 μm, more preferably 50 μm to 80 μm, from the viewpoint of better hiding property of the white reflective layer and better design of the heat shield film.

[Other layers]
The heat-shielding film of the present disclosure may further have a layer other than the white reflective layer and the colored transmissive layer which is an arbitrary layer [hereinafter, may be referred to as another layer].
Examples of other layers include an adhesive layer, a primer layer, an intermediate layer, a base material layer, a surface treatment layer and the like.

(Adhesive layer)
The heat shield film of the present disclosure may have an adhesive layer.
When the heat-shielding film is used by being attached to a base material such as a vehicle or a building, for example, by providing an adhesive layer on the surface of the heat-shielding film on the side in contact with the base material, the base material and the heat-shielding film adhere to each other. The sex can be improved. When the heat shield film is composed of only the white reflective layer, the adhesive layer may be provided on one surface of the white reflective layer. When the heat-shielding film has a white reflective layer and a colored transparent layer, the adhesive layer may be provided on the surface of the white reflective layer opposite to the side having the colored transparent layer.
The adhesive constituting the adhesive layer is not particularly limited, and examples thereof include adhesives containing resins such as acrylic resin, silicone resin, urethane resin, polyisocyanurate, polyvinyl chloride, polyvinylidene chloride, and polystyrene.
Among them, acrylic resin, silicone resin, and urethane resin are preferable, and acrylic resin is more preferable from the viewpoint of better adhesive durability. Acrylic resin has the advantages of good adhesiveness and low cost.

The adhesive layer can be formed, for example, by applying a viscosity-adjusted pressure-sensitive adhesive to one surface of the white reflective layer.
The method of applying the adhesive is not particularly limited, and a known coating method can be applied to form the adhesive layer.
Examples of the coating method include a gravure printing method and a coating method. From the viewpoint of better viscosity of the adhesive forming the adhesive layer and smoothness of the obtained adhesive layer, it is preferable to form the adhesive layer by the coating method.
The thickness of the adhesive layer is preferably 20 μm to 150 μm, more preferably 30 μm to 100 μm, from the viewpoint of further improving the adhesiveness between the heat shield film and the base material.
The thickness of the adhesive layer can be controlled by the amount of the adhesive applied.

The heat-shielding film of the present disclosure has excellent heat-shielding properties because it effectively reflects ultraviolet light and infrared light and suppresses the heat storage action of the heat-shielding film itself, and when used by being attached to a substrate. Also, the influence of heat on the base material can be suppressed.
Examples of the application mode of the heat-shielding film of the present disclosure include exterior materials for vehicles such as automobiles and railways, exterior materials for buildings, interior materials such as wall materials, and the like, which are suitably used for heat-shielding various base materials. Can be.
Since the heat-shielding film of the present disclosure suppresses the heat storage action of the film itself and has good heat-shielding properties with respect to the substrate, it can be suitably used for various applications requiring heat-shielding, and its application range is wide. wide.

Hereinafter, the skin material of the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to the following specific examples.
In the following examples, "%" indicating the concentration and the content of each component is based on mass unless otherwise specified.

[Example 1]
(I: Formation of colored transparent layer)
100 kg of a polyvinyl chloride resin having an average degree of polymerization of 1300 (hereinafter referred to as PVC resin, which is referred to as "PVC" in Tables 1 and 2), 20 kg of a plasticizer composed of a phthalate ester and an epoxidized soybean oil, and a lubricant. As a whole, 3 kg of a fatty acid ester and 3 kg of a Ba / Zn-based heat-resistant stabilizer were sufficiently mixed to obtain a PVC resin-based composition.
To the obtained PVC resin-based composition, 10 kg of an organic pigment composed of phthalocyanine blue, quinacridone, and indolinone was added as a colorant, heated to 150 ° C., melt-kneaded, and sheet-like with a thickness of 80 μm by a calendar method. To form a colored transparent layer.
The hue of the colored transparent layer containing the colored pigment was black. The light transmittance of the obtained colored transparent layer was measured by the method described above using an ultraviolet visible infrared spectrophotometer (model number: UV-3100PC, manufactured by Shimadzu Corporation), and the wavelength was 780 nm to 2500 nm. The transmittance of infrared light was 45% or more, and the transmittance of ultraviolet light having a wavelength of 260 nm to 380 nm was 45% or more.

(II: Formation of white reflective layer)
A PVC resin-based composition was prepared in the same manner as in the above I: colored transmission layer. 126 kg of the obtained PVC resin-based composition, 6 kg of titanium oxide (PO-KL white: trade name, Nikko Bix Co., Ltd., average particle size 1 μm) as a white pigment, and bis (tri) as a fluorescent whitening agent. 3 kg of azinylamide) stilbene sulfonic acid derivative was mixed, heated to 150 ° C., melt-kneaded, and formed into a sheet having a thickness of 80 μm by a calendar method to form a white reflective layer.
The obtained white reflective layer was visually white. When the light reflectance of the white reflective layer was measured by the method described above in accordance with the method described in JIS A 5759 (2008), the light reflectance in the wavelength range of 260 nm to 2500 nm was 83%.

(III: Formation of laminate)
The white reflective layer and the colored transparent layer obtained above were overlapped with each other, and a drawing roll was brought into contact with the colored transparent layer side for laminating embossing to form a laminated body of the white reflective layer and the colored transparent layer. The heating temperature at the time of laminating embossing was 130 ° C.

(IV: Formation of adhesive layer)
Acrylic adhesive [Tg: -40 ° C, molecular weight 800,000, storage elastic modulus at 25 ° C: on the surface of the laminate formed in step III opposite to the side of the white reflective layer having the colored transmission layer: 30 × 10 ⁴ Pa) was applied at a coating amount of 120 g / m ² to form an adhesive layer having a dry film thickness of 40 μm to obtain a heat-shielding film of Example 1.
The heat-shielding film of Example 1 was a black film when observed from the surface, reflecting the hue of the colored transmission layer. In the heat-shielding film of Example 1, the white reflective layer located below was not visible through the black colored transparent layer containing the colored pigment.

[Example 2]
II in Example 1: A heat-shielding film of Example 2 was obtained in the same manner as in Example 1 except that the content of the fluorescent whitening agent was changed from 3 kg to 4.5 kg in the formation of the white reflective layer.

[Example 3]
II in Example 1: A heat-shielding film of Example 3 was obtained in the same manner as in Example 1 except that the content of the fluorescent whitening agent was changed from 3 kg to 6 kg in the formation of the white reflective layer.

[Example 4]
In Example 1, the PVC resin used for forming the I: colored transparent layer and II: white reflective layer was used as an acrylic resin (Acrylic Pet (registered trademark) MF, Mitsubishi Chemical Corporation: Tables 1 and 2). The heat-shielding film of Example 4 was obtained in the same manner as in Example 1 except that it was changed to “acrylic”).

[Example 5]
II in Example 1: In the formation of the white reflective layer, the heat-shielding film of Example 5 was obtained in the same manner as in Example 1 except that the content of the white pigment was changed from 6 kg to 12 kg.

[Example 6]
II in Example 1: In the formation of the white reflective layer, a benzotriazole-based ultraviolet absorber (RUVA-93 (trade name), Otsuka Chemical Co., Ltd .: Tables 1 and 2 show "benzotriazole-based". The heat-shielding film of Example 6 was obtained in the same manner as in Example 1 except that 1 kg was added.

[Comparative Example 1]
II in Example 1: In the formation of the white reflective layer, Comparative Example 1 was carried out in the same manner as in Example 1 except that the fluorescent whitening agent was not used and 3 kg of the benzotriazole-based ultraviolet absorber used in Example 6 was added. A heat shield film was obtained.

[Comparative Example 2]
In the formation of II: white reflective layer in Example 1, a heat-shielding film of Comparative Example 2 was obtained in the same manner as in Example 1 except that a fluorescent whitening agent was not added.

[Comparative Example 3]
In the formation of II: white reflective layer in Example 1, a heat-shielding film of Comparative Example 3 was obtained in the same manner as in Example 1 except that a white pigment was not added.

[Evaluation of heat shield film]
The obtained heat shield film was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.

(1. Heat insulation)
A temperature sensor was fixed on a styrofoam pedestal having a thickness of 30 mm, and a heat shield film collected in a size of 12 cm × 12 cm was attached to the temperature sensor via an adhesive layer.
Using a xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.; which emits light very close to sunlight) under a 20 ° C. 65% RH environment, xenon light with an intensity of 160 W / m ² is directly above the heat shield film. The light was irradiated from a distance of 15 cm for 15 minutes, and the temperature of the heat shield film after the irradiation was measured by the above temperature sensor.
The temperature of the heat-shielding film of Comparative Example 1 was measured in the same manner as above, and the value was used as a control example (reference value). The difference was measured and evaluated according to the following evaluation criteria. Evaluation A was evaluated as a level at which the heat shielding effect in the present disclosure was exhibited.
(Evaluation criteria)
A: The temperature is lower than that of the heat shield film of the control example.
B: The temperature is the same or higher than that of the heat shield film of the control example.

(2. Weather resistance)
In accordance with JIS K5602 (2008), the accelerated weather resistance test of the heat shield film was performed with a metal halide lamp type super accelerated weather resistance tester (manufactured by Daipla Wintes Co., Ltd.), and the heat shield after the light resistance test was performed. The film was visually evaluated according to the following criteria.
The accelerated light resistance test was carried out using the above-mentioned device under the conditions of an irradiance of 650 W / m ² for a metal halide lamp and a black panel temperature (test piece temperature) of 53 ° C. Evaluation A was evaluated as a level at which there was no practical problem.
(Evaluation criteria)
A: No change in appearance was observed in the test piece after the accelerated weather resistance test as compared with the test piece before the accelerated weather resistance test.
B: Changes such as cracks and delamination that can be visually confirmed were observed on the test piece after the accelerated weathering test.

From the results of Tables 1 and 2, the heat-shielding films of Examples 1 to 6 both have a heat-shielding property with respect to the heat-shielding film of Comparative Example 1 containing an ultraviolet absorber and not a fluorescent whitening agent. Turns out to be excellent. In addition, all the heat-shielding films had good weather resistance and were at a level where there was no problem in practical use.

On the other hand, the heat-shielding film of Comparative Example 2 containing no fluorescent whitening agent and ultraviolet absorber has a practically problematic level of weather resistance, and the heat-shielding film of Comparative Example 3 containing no white pigment is It was inferior in heat insulation.

10 Heat-shielding film 12 Colored transparent layer 14 White reflective layer 16 Adhesive layer

Claims (7)

It has at least a white reflective layer and
The white reflective layer is 0.1% by mass based on at least one synthetic resin selected from the group consisting of a polyvinyl chloride resin, an acrylic resin and a fluororesin, a white pigment, and the total solid content of the white reflective layer. A heat shield film containing up to 5.0% by mass of a fluorescent whitening agent. The heat-shielding film according to claim 1, wherein the white reflective layer does not contain an ultraviolet absorber. The heat-shielding film according to claim 1 or 2, wherein the synthetic resin contains at least one selected from the group consisting of a polyvinyl chloride resin and an acrylic resin. A colored transparent layer containing a synthetic resin and a colorant is provided on one surface of the white reflective layer.
The heat-shielding film according to any one of claims 1 to 3, wherein the colorant does not contain carbon black. The heat shield film according to claim 4, wherein the synthetic resin contained in the colored transparent layer contains at least one selected from the group consisting of a polyvinyl chloride resin and an acrylic resin. The heat-shielding film according to any one of claims 1 to 5, which is an exterior material of a vehicle. The heat-shielding film according to any one of claims 1 to 5, which is an exterior material of a building.

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