Patent Application
20250206997
The present invention relates to a window material and a light-transparent roof material. The present invention also relates to architecture, and vehicles, ships, or aircraft including the window material and/or the light-transparent roof material.
There are needs for architectures such as office buildings and arcades, and transports such as vehicles, ships, and aircraft, to reduce direct sunlight at high temperatures in summer and to let in solar radiation at low temperatures in winter. For this, a temperature-sensitive dimming liquid laminated body in which the degree of cloudiness changes autonomously in response to temperature stimulation has been proposed as a structure to be provided in a window (Patent Document 1).
However, there is a problem that providing the above-mentioned laminated body requires a dedicated structure body to maintain the shape of the temperature-sensitive dimming liquid, and a window provided with the above-mentioned laminated body has a complicated structure and time and labor are required for manufacturing.
The present invention was made in view of the above problems and has an object to provide a window material and a light-transparent roof material capable of autonomously changing the degree of cloudiness in response to temperature and being easily manufactured without having a complicated structure, and architectures, and vehicles, ships, or aircraft, including the window material and/or the light-transparent roof material.
A first aspect of the present invention is
A second aspect of the present invention is
A third aspect of the present invention is an architecture including the window material as described in the first aspect and/or a light-transparent roof material as described in the second aspect.
A fourth aspect of the present invention is a vehicle, a ship, or an aircraft including the window material as described in the first aspect and/or the light-transparent roof material as described in the second aspect.
A fifth aspect of the present invention is
A sixth aspect of the present invention is
The present invention can provide a window material and a light-transparent roof material capable of autonomously changing the degree of cloudiness in response to temperatures and being easily manufactured without having a complicated structure, and architectures, vehicles, ships, or aircrafts including the window material and/or light-transparent roof material.
Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications added within the scope of the purpose of the present invention. Note here that each drawing shown below is a schematic view, and the size and shape of each part are appropriately exaggerated or omitted for easy understanding.
In
Note here that it can also be designed so that the difference in the refractive index between the temperature-sensitive fine particles 12b and 22b and the adhesive agents becomes smaller as the temperature rises.
In this case, for example, when the temperature is relatively low and the amount of sunlight is low, such as in the morning or at night, the window material functions as frost glass. Meanwhile, when the temperature rises as the amount of sunlight increases during the day time, the window material becomes transparent, so sunlight can be allowed to enter into the room.
Furthermore, when the above window materials are installed in a location exposed to the outside air, the above window material become cloudy or transparent as the outside temperature rises, so it also has a function of making people being in air-conditioned rooms be visually aware of the rise in outside temperature.
Hereinafter, each layer constituting the first window material 10 and the second window material 20 is described.
A light-transparent base material constituting a light-transparent base material layer is not particularly limited as long as it is a base material that can be used as window materials for architectures, vehicles, ships, and aircraft, and, for example, a glass plate or a resin plate can be used. Examples of the material for the glass plate include soda lime glass, borosilicate glass, high silica glass, and the like. Examples of the material for the resin plate include polyalkyl methacrylates such as polymethyl methacrylate, polyalkyl acrylate, polycarbonate, polymethylstyrene, acrylonitrile-styrene copolymers, and the like.
A thickness of the light-transparent base material layer is not particularly limited, but is, for example, 0.1 mm or more and 10 mm or less. Examples of the shape of the light-transparent base material layer include a planar shape like the first window material 10 and the second window material 20, a curved shape, and the like.
The light-transparent base material layer includes at least one layer, and may include a single layer like the first window material 10, or two or more layers like the second window material 20. When the light-transparent base material layer includes two or more layers, each layer may be made of the same type of base material, or may be made of different types of base materials. Furthermore, the layers may have the same thickness, or different thicknesses.
The adhesive layer is a layer made of an adhesive composition containing 1 to 100 parts by mass of temperature-sensitive fine particles with respect to 100 parts by mass of the adhesive agent, and has the function of autonomously changing the degree of cloudiness depending on the temperature.
A thickness of the adhesive layer is not particularly limited, but is preferably 5 μm or more and 1 mm or less, and more preferably 10 μm or more and 100 μm or less. Note here that the thicker the adhesive layer is, the more the dimming function tends to be exhibited with addition of a small amount of temperature-sensitive fine particles. As the thickness is smaller, the larger amount of the temperature-sensitive fine particles needs to be added in order to exhibit the dimming function.
The adhesive layer includes at least one layer. The adhesive layer may include a single layer like the first window material 10 and the second window material 20, or may include two or more layers. The arrangement of the adhesive layer with respect to the light-transparent base material layer is not particularly limited. The adhesive layer may be disposed on a side of the light-transparent base material layer where sunlight enters, or may be disposed on the opposite side. When the light-transparent base material layer includes two or more layers, the adhesive layer may be disposed between the light-transparent base material layers like the second window material 20.
Note here that the adhesive layer may cover the entire surface of a surface where the adhesive layer and the light-transparent base material layer are in contact with each other, or may cover a part of the surface.
When the adhesive layer covers a part of the surface where the adhesive layer and the light-transparent base material layer are in contact with each other, a character, a symbol, a pattern, a figure, a picture, and the like, may be drawn on the light-transparent base material layer by the adhesive layer. In this case, the adhesive layer may form a character or a pattern, or a region surrounded by the adhesive layer may form a character or a pattern. Such window materials have excellent design properties when haze appears or disappears at high temperatures.
Furthermore, the adhesive layer may have a plurality of types of regions with different haze values at high temperatures or low temperatures. The haze value of the adhesive layer can be changed by changing the type of adhesive agents or temperature-sensitive fine particles, or by changing the amount of temperature-sensitive fine particles used.
For example, by continuously forming a plurality of adhesive layers having different haze values at high temperatures or low temperatures on a light-transparent base material in a belt-like shape, a window material excellent in design property exhibiting gradated haze at high temperatures or low temperatures can be provided.
The haze value of the adhesive layer at 40° C. is preferably higher by 10% or more than the haze value at 23° C. This tends to make it easier to visually recognize changes in degree of cloudiness depending on temperature. Note here that in this description, the haze value of the adhesive layer is a value measured by the method described in Examples below.
The haze value of the adhesive layer at 23° C. is preferably 10% or less, and more preferably 5% or less. The lower limit of the haze value at 23° C. is not particularly limited. Furthermore, the haze value of the adhesive layer at 40° C. is preferably 12% or more, more preferably 20% or more, and still more preferably 30% or more. The upper limit of the haze value at 40° C. is not particularly limited, but is, for example, 70% or less, or 50% or less.
The transmittance of solar radiation through the adhesive layer at 40° C. is preferably lower by 10% or more than the transmittance of solar radiation at 23° C. Note here that in this description, the transmittance of solar radiation through the adhesive layer is a value measured by the method described in Examples below.
The transmittance of solar radiation through the adhesive layer at 23° C. is preferably 50% or more, more preferably 60% or more, and still more preferably 70% or more. The upper limit of the transmittance of solar radiation at 23° C. is not particularly limited, but is, for example, 95% or less, or 85% or less. Furthermore, the transmittance of solar radiation of the adhesive layer at 40° C. is preferably 70% or less, more preferably 60% or less, and still more preferably 50% or less. The lower limit of the transmittance of solar radiation at 40° C. is not particularly limited.
The refractive index of the temperature-sensitive fine particles at (melting point +7°) C is preferably lower by 0.02 or more than the refractive index of the temperature-sensitive fine particles at (melting point −10° C.) This tends to make it easier to visually recognize changes in the degree of cloudiness depending on temperature. Note here that in this description, the refractive index is a value measured by the method described in Examples below.
The melting point of the temperature-sensitive fine particles is preferably 20° C. or higher, and more preferably 25° C. or higher. Furthermore, the melting point is preferably 100° C. or lower, more preferably 60° C. or lower, and still more preferably 40° C. or lower. Note here that in this description, the melting point of the temperature-sensitive fine particles is a value measured by the method described in Examples below.
The melting point of the temperature-sensitive fine particles can be adjusted, for example, by changing the composition of the monomer components constituting the side chain crystalline polymer included in the temperature-sensitive fine particles. Specifically, for example, by changing a length of a side chain in a side chain crystalline polymer, the melting point can be adjusted. When the length of the side chain is long, the temperature-sensitive fine particle tends to have a high melting point.
The average particle diameter of the temperature-sensitive fine particles is preferably 1 μm or more, and more preferably 3 μm or more. Furthermore, the above average particle diameter is preferably 100 μm or less, and more preferably 30 μm or less. In particular, from the viewpoint of easily increasing the haze, the average particle diameter is more preferably 3 μm or more and 10 μm or less, and most preferably 3 μm or more and 6 μm or less. From the viewpoint of easily suppressing the transmission of solar radiation, the average particle diameter is more preferably 6 μm or more and 14 μm or less, and most preferably 6 μm or more and 10 μm or less. From the viewpoint of easily shielding heat, the average particle diameter is more preferably 6 μm or more and 25 μm or less, and most preferably 14 μm or more and 25 μm or less.
Furthermore, the D90 particle diameter of the temperature-sensitive fine particles is preferably not more than the thickness of the adhesive layer, and is, for example, 1 μm or more and 1000 μm or less, or 3 μm or more and 100 μm or less. When the D90 particle diameter is not more than the thickness of the adhesive layer, the surface of the adhesive layer becomes uniform and the adhesive force tends less likely to be impaired.
Note here that in this description, the average particle diameter and D90 particle diameter of the temperature-sensitive fine particles are values measured by the method described in Examples below.
The temperature-sensitive fine particle preferably includes a side chain crystalline polymer. The side chain crystalline polymer preferably includes a constituent unit derived from a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms. In the constituent unit derived from a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms, the linear alkyl group having 14 or more carbon atoms acts as a side chain crystalline site in the side chain crystalline polymer. In other words, the side chain crystalline polymer is, for example, a comb-shaped polymer including a linear alkyl group having 14 or more carbon atoms in the side chain. When the side chains are aligned in an ordered arrangement by intermolecular force or the like, the side chain crystalline polymer crystallizes. Note that the above-mentioned (meth)acrylic monomer is an acrylic monomer or a methacrylic monomer. The upper limit of the number of carbon atoms in the linear alkyl group is preferably 50 or less, and more preferably 30 or less.
Examples of the (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms include cetyl (meth)acrylate, stearyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, and the like. These may be used alone or in combination of two or more of these.
The ratio of the mass of the constituent unit derived from the (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms to the mass of the side chain crystalline polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more. The above ratio may be 100% by mass, but is preferably 95% by mass or less.
The side chain crystalline polymer may include a constituent unit derived from any other monomer copolymerizable with a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms. Examples of other monomers include monofunctional monomers, polyfunctional monomers, and refractive index adjusting monomers. In other words, the side chain crystalline polymer may include a constituent unit derived from a monofunctional monomer, a polyfunctional monomer, or a refractive index adjusting monomer.
Examples of monofunctional monomers include (meth)acrylic monomers having an alkyl group having 1 to 12 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, lauryl (meth)acrylate, and 2-ethylhexyl acrylate. These may be used alone or in combination of two or more of these. Note here that when any function is preferably added in addition to temperature sensitivity, any monomer that can be copolymerized with a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms and has the function can be freely copolymerized.
The ratio of the mass of the constituent unit derived from the monofunctional monomer to the mass of the side chain crystalline polymer is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 20% by mass or less, and more preferably 10% by mass or less.
The polyfunctional monomer can crosslink a plurality of molecular chains included in the side chain crystalline polymer. From the viewpoint of the dispersion state of the temperature-sensitive fine particles during use, suppressing deformation, and maintaining repeatability of functions, the side chain crystalline polymer preferably includes a constituent unit derived from a polyfunctional monomer. In other words, the temperature-sensitive fine particles and the side chain crystalline polymer are preferably crosslinked. The polyfunctional monomer has two or more, preferably 2 to 4, radically polymerizable double bonds in the molecule. Examples of the polyfunctional monomer include bifunctional (meth)acrylate, trifunctional (meth)acrylate, tetrafunctional (meth)acrylate, and the like. Specific examples include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyethylene glycol 200 di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, and the like. These may be used alone or in combination of two or more of these. The polyfunctional monomer may be at least one selected from bifunctional (meth)acrylate, trifunctional (meth)acrylate, and tetrafunctional (meth)acrylate.
The ratio of the mass of the constituent unit derived from the polyfunctional monomer to the mass of the side chain crystalline polymer is preferably 0.10% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 20% by mass or less, and more preferably 10% by mass or less.
The refractive index adjusting monomer may be a monomer having a refractive index of 1.300 to 1.600. Examples of the refractive index adjusting monomer include 2-(0-phenylphenoxy)ethyl acrylate (refractive index: 1.577), 2-propenoic acid (3-phenoxyphenyl)methyl ester (refractive index: 1.566), 1-naphthyl acrylate (refractive index: 1.595), acrylamide (refractive index: 1.515), hydroxyacrylamide (refractive index: 1.515), EO-modified bisphenol A diacrylate (refractive index: 1.537), acrylamide (refractive index: 1.515), 2,2,2-trifluoroethyl acrylate (refractive index: 1.348), methacryl-modified poly dimethylsiloxane (refractive index: 1.408), and the like. These may be used alone or in combination of two or more of these.
The ratio of the mass of the constituent unit derived from the refractive index adjusting monomer to the mass of the side chain crystalline polymer is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less.
Since dispersibility in adhesive agent tends to be good, the temperature-sensitive fine particles preferably do not include a constituent unit derived from a reactive emulsifier. A reactive emulsifier is an emulsifier having a polymerizable unsaturated bond such as a vinyl group in its molecule. A reactive emulsifier is a polymerizable monomer that has an emulsifying function and has a polymerizable group having an unsaturated bond such as a vinyl group in its molecule, and a hydrophilic group.
In the adhesive composition, the content of the temperature-sensitive fine particles is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the adhesive agent. The content is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and still more preferably 40 parts by mass or more. Furthermore, the above content is preferably 70 parts by mass or less.
The method for producing temperature-sensitive fine particles is not particularly limited, and conventionally known polymerization methods such as miniemulsion polymerization and suspension polymerization can be employed.
The adhesive agent is not particularly limited, and conventionally known adhesive agents such as acrylic adhesive agents, natural rubber adhesive agents, synthetic rubber adhesive agents, silicone adhesive agents, and urethane adhesive agents can be used. Among them, acrylic adhesive agents are preferable.
The polymer constituting the adhesive agent preferably includes a constituent unit derived from an adhesive monomer that contributes to adhesiveness and a constituent unit derived from a functional group monomer for crosslinking. The polymer constituting the adhesive agent may include constituent units derived from other monomers copolymerizable with these monomers. Examples of other monomers include refractive index adjusting monomers. In other words, the polymer constituting the adhesive agent may include a constituent unit derived from a refractive index adjusting monomer.
Examples of adhesive monomers include (meth)acrylates having an alkyl group having 1 to 12 carbon atoms, such as ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; (meth)acrylates with ethylene glycol groups such as 2-ethylhexyl-diglycol (meth)acrylate, methoxyethyl (meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, ethoxy-diethylene glycol (meth)acrylate; ethylenically unsaturated monomers such as styrene and vinyl acetate; and the like. These may be used alone or in combination of two or more of these. Among these, (meth)acrylates having an alkyl group having 1 to 12 carbon atoms are preferred.
The ratio of the mass of the constituent unit derived from the adhesive monomer to the mass of the polymer constituting the adhesive agent is preferably 50% by mass or more, and more preferably 70% by mass or more. Furthermore, the above ratio is preferably 99.9% by mass or less, and more preferably 90% by mass or less.
Examples of functional group monomers include (meth)acrylates having a hydroxyalkyl group such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxyhexyl (meth)acrylate; ethylenically unsaturated monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; and the like. These may be used alone or in combination of two or more of these. Among these, ethylenically unsaturated monomers having a carboxyl group are preferred.
The ratio of the mass of the constituent unit derived from the functional group monomer to the mass of the polymer constituting the adhesive agent is preferably 0.10% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less. When the ratio is 0.10% by mass or more, shape retention property tends to be good. When the ratio is 30% by mass or less, the viscosity is not excessively high and coating property tends to be good.
The refractive index adjusting monomer may be a monomer having a refractive index of 1.300 to 1.600. Examples of the refractive index adjusting monomer include 2-(0-phenylphenoxy)ethyl acrylate (refractive index: 1.577), 2-propenoic acid (3-phenoxyphenyl) methyl ester (refractive index: 1.566), 1-naphthyl acrylate (refractive index: 1.595), acrylamide (refractive index: 1.515), hydroxyacrylamide (refractive index: 1.515), EO-modified bisphenol A diacrylate (refractive index: 1.537), acrylamide (refractive index: 1.515), 2,2,2-trifluoroethyl acrylate (refractive index: 1.348), methacryl-modified poly dimethylsiloxane (refractive index: 1.408), and the like. These may be used alone or in combination of two or more of these.
The ratio of the mass of the constituent unit derived from the refractive index adjusting monomer to the mass of the polymer constituting the adhesive agent is preferably 0.10% by mass or more, more preferably 1% by mass or more, and still more preferably 10% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less.
The weight average molecular weight of the adhesive agent is preferably 200,000 or more, and more preferably 300,000 or more. The above weight average molecular weight is preferably 2,000,000 or less, more preferably 1,000,000 or less, and still more preferably 600,000 or less. When the weight average molecular weight is 200,000 or more, the shape retention property tends to be good. When the weight average molecular weight is 2,000,000 or less, the viscosity is not excessively high and coating property tends to be good. Note here that in this description, the weight average molecular weight of an adhesive agent is a value measured by the method described in Examples below.
The glass transition temperature (Tg) of the adhesive agent is preferably 25° C. or lower from the viewpoint that high adhesive force is exhibited. In this description, the glass transition temperature is a value measured by the method described in Examples below.
The difference in refractive index at 23° C. between the adhesive agent and the temperature-sensitive fine particles is preferably less than 0.015, and more preferably less than 0.010. Furthermore, the refractive index difference at 40° C. is preferably 0.015 or more. The upper limit of the refractive index difference at 40° C. is not particularly limited, but is, for example, 0.1.
Thus, in general, the adhesive layer exhibits high light-transparency in a warm atmosphere where humans and pets can live comfortably, and in high-temperature atmospheres such as summer, the adhesive layer exhibits haze and light-transparency decreases.
Furthermore, by adjusting the refractive indices of the adhesive agent and the temperature-sensitive fine particles, the refractive index difference between the adhesive agent and the temperature-sensitive crosslinked fine particles at 23° C. can be designed to be 0.015 or more, and the refractive index difference at 40° C. be less than 0.015.
In this case, for example, when an adhesive agent is applied to a window glass, the window glass functions as frost glass under the condition that the temperature is relatively low and the amount of sunlight is small, such as in the morning and at night, and on the other hand, when the temperature rises with the increase of the amount of sunlight in the daytime, the window glass becomes transparent and the room can be efficiently lightened. Thus, lightening to a room only in the daytime can be easily carried out without opening and closing a curtain.
The ratio of the mass of the adhesive agent to the mass of the solid content of the adhesive composition is not particularly limited, but is, for example, 50% by mass or more and 95% by mass or less. Note here that in this description, the solid content of the adhesive composition means all the components except a solvent such as an aqueous solvent and an organic solvent from the adhesive composition.
The method for producing the adhesive agent is not particularly limited, and the adhesive agent can be obtained by conventionally known polymerization methods such as solution polymerization and UV polymerization.
The adhesive composition may contain a crosslinking agent for crosslinking the adhesive agent. In other words, the adhesive agent may be crosslinked. Examples of the crosslinking agents used include aziridine crosslinking agents, metal chelate crosslinking agents, epoxy crosslinking agents, and isocyanate crosslinking agents.
In the adhesive composition, the content of the crosslinking agent is not particularly limited, but is, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the adhesive agent. When the content is 0.1 parts by mass or more, the shape retention property tends to be less likely to decrease. Furthermore, when the content is 10 parts by mass or less, high adhesive force tends to be easily exhibited.
The adhesive composition may include other additives such as a solvent such as an organic solvent, an inhibitor that suppresses the progress of crosslinking, an adhesion giving resin (tackifier), an ultraviolet (UV) absorber, a light stabilizer (HALS), an antioxidant, an infrared absorber, dyes and pigments.
The above window material may or may not include a base material sheet. The base material sheet has a function as a support when laminating the adhesive layer on the light-transparent base material layer, and a function as a protective layer for the adhesive layer.
The base material constituting the base material sheet is not particularly limited as long as it is a light-transparent base material. Examples of the base material include PET such as corona treated PET, untreated PET, highly transparent PET, annealed PET, UV cut PET, heat shielding PET, anti-fog PET, hard coat PET, blasted PET; transparent PI, and the like.
The method for producing the above window material is not particularly limited, and examples thereof include a method of coating a base material sheet with an adhesive composition to produce an adhesive sheet, and then pasting the adhesive sheet on a light-transparent base material, and the like. The adhesive layer may be formed by directly coating the light-transparent base material with the adhesive composition. In this case, it is preferable to cover the exposed surface of the adhesive layer formed on the light-transparent base material with a base material sheet so that a tacky surface of the adhesive layer is not exposed indoors or outdoors. Furthermore, when the light-transparent base material layer includes two or more light-transparent base material layers like the second window material 20, the method also includes a method of arranging an adhesive layer between the light-transparent base material layers, and the like. In this case, after applying an adhesive composition on one base material layer to form an adhesive layer, another base material layer may be pasted onto the exposed surface of the adhesive layer.
Furthermore, the second window material 20 including an adhesive layer between light-transparent base materials can be produced by preparing two laminated bodies in which one light-transparent base material layer and one adhesive layer are laminated so that they are in contact with each other, and pasting the two laminated bodies together on the exposed surface of the adhesive layer.
The mode of use of the window material described above is not particularly limited. The mode of use of the window material described above can be appropriately selected depending on the purposes. The window material described above can be suitably used, for example, in architecture such as houses, buildings, warehouses, and arcades, as well as in vehicles, ships, and aircraft.
In
Note here that it can also be designed so that the difference in the refractive index between the temperature-sensitive fine particles 32b and the adhesive agent 32a becomes smaller as the temperature rises.
For the light-transparent roof material, each layer of the light-transparent base material layer, the adhesive layer, the base material sheet, the production method, and application of use are the same as each layer, production method, and application of use of the window material.
The adhesive composition contains 1 to 100 parts by mass of temperature-sensitive fine particles with respect to 100 parts by mass of the adhesive agent.
The refractive index of temperature-sensitive fine particles decreases as the temperature rises, and the refractive index reduction rate, as an amount of decrease in the refractive index per 1° C. being larger near the melting point than in a temperature range not near the melting point. Therefore, when an adhesive layer is formed from an adhesive composition, when the temperature of the adhesive layer increases due to solar radiation or air temperature, the difference in refractive index between the temperature-sensitive fine particles and the adhesive agent increases, and a haze value becomes high. On the other hand, when the temperature of the adhesive layer decreases, the difference in refractive index between the temperature-sensitive fine particles and the adhesive agent becomes smaller, resulting in a lower haze value. On the contrary, when each refractive index is adjusted so that the difference in refractive index between the temperature-sensitive fine particles and the adhesive agent becomes small at high temperatures, the haze value decreases as the temperature of the adhesive layer rises, and the haze value increases as the temperature of the adhesive layer decreases.
As a result, in the former case, the degree of cloudiness can be autonomously changed depending on temperatures, and direct sunlight can be softened during high temperatures in summer, and sunlight can be allowed to enter during low temperatures in winter.
Furthermore, when an adhesive layer is formed using an adhesive composition so that designs such as a character, a symbol, a pattern, a figure, a picture, and the like, are drawn, when haze appears or disappears due to high temperatures by heat sources such as lighting, sunlight, and air temperature, the design can be allowed to appear or disappear. This makes it possible to impart excellent display properties (designs such as a character and a symbol) and decorative properties (designs such as a pattern, a figure, and a picture) to the object provided with the adhesive layer.
The refractive index of the temperature-sensitive fine particles decreases as the temperature rises, and the refractive index reduction rate, which is the amount of decrease in the refractive index per 1° C., decreases more near the melting point than in a temperature range not near the melting point.
The refractive index of the temperature-sensitive fine particles at (melting point +7°) C is preferably lower by 0.02 or more than the refractive index of the temperature-sensitive fine particles at (melting point −10° C.) This tends to make it easier to visually recognize changes in the degree of cloudiness depending on temperature.
The melting point of the temperature-sensitive fine particles is preferably 20° C. or higher, and more preferably 25° C. or higher. Furthermore, the melting point is preferably 100° C. or lower, more preferably 60° C. or lower, and still more preferably 40° C. or lower.
The melting point of the temperature-sensitive fine particles can be adjusted, for example, by changing the composition of the monomer components constituting the side chain crystalline polymer included in the temperature-sensitive fine particles. Specifically, for example, by changing a length of a side chain in a side chain crystalline polymer, the melting point can be adjusted. When the length of the side chain is long, the temperature-sensitive fine particle tends to have a high melting point.
The average particle diameter of the temperature-sensitive fine particles is preferably 1 μm or more, and more preferably 3 μm or more. Furthermore, the above average particle diameter is preferably 100 μm or less, and more preferably 30 μm or less. In particular, from the viewpoint of easily increasing the haze, the average particle diameter is more preferably 3 μm or more and 10 μm or less, and most preferably 3 μm or more and 6 μm or less. From the viewpoint of easily suppressing the transmission of solar radiation, the average particle diameter is more preferably 6 μm or more and 14 μm or less, and most preferably 6 μm or more and 10 μm or less. From the viewpoint of easily shielding heat, the average particle diameter is more preferably 6 μm or more and 25 μm or less, and most preferably 14 μm or more and 25 μm or less.
Furthermore, the D90 particle diameter of the temperature-sensitive fine particles is preferably not more than the thickness of the adhesive layer, and is, for example, 1 μm or more and 1000 μm or less, or 3 μm or more and 100 μm or less. When the D90 particle diameter is not more than the thickness of the adhesive layer, the surface of the adhesive layer becomes uniform and the adhesive force tends less likely to be impaired.
The temperature-sensitive fine particle preferably includes a side chain crystalline polymer. The side chain crystalline polymer preferably includes a constituent unit derived from a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms. In the constituent unit derived from a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms, the linear alkyl group having 14 or more carbon atoms acts as a side chain crystalline site in the side chain crystalline polymer. In other words, the side chain crystalline polymer is, for example, a comb-shaped polymer including a linear alkyl group having 14 or more carbon atoms in the side chain. When the side chains are aligned in an ordered arrangement by intermolecular force or the like, the side chain crystalline polymer crystallizes. Note that the above-mentioned (meth)acrylic monomer is an acrylic monomer or a methacrylic monomer. The upper limit of the number of carbon atoms in the linear alkyl group is preferably 50 or less, and more preferably 30 or less.
Examples of the (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms include cetyl (meth)acrylate, stearyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, and the like. These may be used alone or in combination of two or more of these.
In the side chain crystalline polymer, the constituent unit derived from a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms is preferably 70% by mass or more, more preferably 80% by mass or more, and further more preferably 90% by mass or more. The above constituent unit may be 100% by mass, but preferably 95% by mass or less.
The side chain crystalline polymer may include a constituent unit derived from any other monomer copolymerizable with a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms. Examples of other monomers include monofunctional monomers, polyfunctional monomers, and refractive index adjusting monomers. In other words, the side chain crystalline polymer may include a constituent unit derived from a monofunctional monomer, a polyfunctional monomer, or a refractive index adjusting monomer.
Examples of monofunctional monomers include (meth)acrylic monomers having an alkyl group having 1 to 12 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, lauryl (meth)acrylate, and 2-ethylhexyl acrylate. These may be used alone or in combination of two or more of these. Note here that when any function is preferably added in addition to temperature sensitivity, any monomer that can be copolymerized with a (meth)acrylic monomer including a linear alkyl group having 14 or more carbon atoms and has the function can be freely copolymerized.
The ratio of the mass of the constituent unit derived from the monofunctional monomer to the mass of the side chain crystalline polymer is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 20% by mass or less, and more preferably 10% by mass or less.
The polyfunctional monomer can crosslink a plurality of molecular chains included in the side chain crystalline polymer. From the viewpoint of the dispersion state of the temperature-sensitive fine particles during use, suppressing deformation, and maintaining repeatability of functions, the side chain crystalline polymer preferably includes a constituent unit derived from a polyfunctional monomer. In other words, the temperature-sensitive fine particles and the side chain crystalline polymer are preferably crosslinked. The polyfunctional monomer has two or more, preferably 2 to 4, radically polymerizable double bonds in the molecule. Examples of the polyfunctional monomer include bifunctional (meth)acrylate, trifunctional (meth)acrylate, tetrafunctional (meth)acrylate, and the like. Specific examples include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyethylene glycol 200 di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, and the like. These may be used alone or in combination of two or more of these. The polyfunctional monomer may be at least one selected from bifunctional (meth)acrylate, trifunctional (meth)acrylate, and tetrafunctional (meth)acrylate.
The ratio of the mass of the constituent unit derived from the polyfunctional monomer to the mass of the side chain crystalline polymer is preferably 0.10% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 20% by mass or less, and more preferably 10% by mass or less.
The refractive index adjusting monomer may be a monomer having a refractive index of 1.300 to 1.600. Examples of the refractive index adjusting monomer include 2-(0-phenylphenoxy)ethyl acrylate (refractive index: 1.577), 2-propenoic acid (3-phenoxyphenyl)methyl ester (refractive index: 1.566), 1-naphthyl acrylate (refractive index: 1.595), acrylamide (refractive index: 1.515), hydroxyacrylamide (refractive index: 1.515), EO-modified bisphenol A diacrylate (refractive index: 1.537), acrylamide (refractive index: 1.515), 2,2,2-trifluoroethyl acrylate (refractive index: 1.348), methacryl-modified poly dimethylsiloxane (refractive index: 1.408), and the like. These may be used alone or in combination of two or more of these.
The ratio of the mass of the constituent unit derived from the refractive index adjusting monomer to the mass of the side chain crystalline polymer is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less.
Since dispersibility in adhesive agent tends to be good, the temperature-sensitive fine particles preferably do not include a constituent unit derived from a reactive emulsifier. A reactive emulsifier is an emulsifier having a polymerizable unsaturated bond such as a vinyl group in its molecule. A reactive emulsifier is a polymerizable monomer that has an emulsifying function and has a polymerizable group having an unsaturated bond such as a vinyl group in its molecule, and a hydrophilic group.
In the adhesive composition, the content of the temperature-sensitive fine particles is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the adhesive agent. The content is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and still more preferably 40 parts by mass or more. Furthermore, the above content is preferably 70 parts by mass or less.
The method for producing temperature-sensitive fine particles is not particularly limited, and conventionally known polymerization methods such as miniemulsion polymerization and suspension polymerization can be employed.
The adhesive agent is not particularly limited, and conventionally known adhesive agents such as acrylic adhesive agents, natural rubber adhesive agents, synthetic rubber adhesive agents, silicone adhesive agents, and urethane adhesive agents can be used. Among them, acrylic adhesive agents are preferable.
The polymer constituting the adhesive agent preferably includes a constituent unit derived from an adhesive monomer that contributes to adhesiveness and a constituent unit derived from a functional group monomer for crosslinking. The polymer constituting the adhesive agent may include constituent units derived from other monomers copolymerizable with these monomers. Examples of other monomers include refractive index adjusting monomers. In other words, the polymer constituting the adhesive agent may include a constituent unit derived from a refractive index adjusting monomer.
Examples of adhesive monomers include (meth)acrylates having an alkyl group having 1 to 12 carbon atoms, such as ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; (meth)acrylates with ethylene glycol groups such as 2-ethylhexyl-diglycol (meth)acrylate, methoxyethyl (meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, ethoxy-diethylene glycol (meth)acrylate; ethylenically unsaturated monomers such as styrene and vinyl acetate; and the like. These may be used alone or in combination of two or more of these. Among these, (meth)acrylates having an alkyl group having 1 to 12 carbon atoms are preferred.
The ratio of the mass of the constituent unit derived from the adhesive monomer to the mass of the polymer constituting the adhesive agent is preferably 50% by mass or more, and more preferably 70% by mass or more. Furthermore, the above ratio is preferably 99.9% by mass or less, and more preferably 90% by mass or less.
Examples of functional group monomers include (meth)acrylates having a hydroxyalkyl group such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxyhexyl (meth)acrylate; ethylenically unsaturated monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; and the like. These may be used alone or in combination of two or more of these. Among these, ethylenically unsaturated monomers having a carboxyl group are preferred.
The ratio of the mass of the constituent unit derived from the functional group monomer to the mass of the polymer constituting the adhesive agent is preferably 0.10% by mass or more, and more preferably 1% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less. When the ratio is 0.10% by mass or more, shape retention property tends to be good. When the ratio is 30% by mass or less, the viscosity is not excessively high and coating property tends to be good.
The refractive index adjusting monomer may be a monomer having a refractive index of 1.300 to 1.600. Examples of the refractive index adjusting monomer include 2-(0-phenylphenoxy)ethyl acrylate (refractive index: 1.577), 2-propenoic acid (3-phenoxyphenyl) methyl ester (refractive index: 1.566), 1-naphthyl acrylate (refractive index: 1.595), acrylamide (refractive index: 1.515), hydroxyacrylamide (refractive index: 1.515), EO-modified bisphenol A diacrylate (refractive index: 1.537), acrylamide (refractive index: 1.515), 2,2,2-trifluoroethyl acrylate (refractive index: 1.348), methacryl-modified poly dimethylsiloxane (refractive index: 1.408), and the like. These may be used alone or in combination of two or more of these.
The ratio of the mass of the constituent unit derived from the refractive index adjusting monomer to the mass of the polymer constituting the adhesive agent is preferably 0.10% by mass or more, more preferably 1% by mass or more, and still more preferably 10% by mass or more. Furthermore, the above ratio is preferably 30% by mass or less.
The weight average molecular weight of the adhesive agent is preferably 200,000 or more, and more preferably 300,000 or more. The above weight average molecular weight is preferably 2,000,000 or less, more preferably 1,000,000 or less, and still more preferably 600,000 or less. When the weight average molecular weight is 200,000 or more, the shape retention property tends to be good. When the weight average molecular weight is 2,000,000 or less, the viscosity is not excessively high and coating property tends to be good.
The glass transition temperature (Tg) of the adhesive agent is preferably 25° C. or lower from the viewpoint that high adhesive force is exhibited.
The difference in refractive index at 23° C. between the adhesive agent and the temperature-sensitive fine particles is preferably less than 0.015, and more preferably less than 0.010. Furthermore, the refractive index difference at 40° C. is preferably 0.015 or more. The upper limit of the refractive index difference at 40° C. is not particularly limited, but is, for example, 0.1.
The ratio of the mass of the adhesive agent to the mass of the solid content of the adhesive composition is not particularly limited, but is, for example, 50% by mass or more and 95% by mass or less. Note here that in this description, the solid content of the adhesive composition means all the components except a solvent such as an aqueous solvent and an organic solvent from the adhesive composition.
The method for producing the adhesive agent is not particularly limited, and the adhesive agent can be obtained by conventionally known polymerization methods such as solution polymerization and UV polymerization.
The adhesive composition may contain a crosslinking agent for crosslinking the adhesive agent. In other words, the adhesive agent may be crosslinked. Examples of the crosslinking agents used include aziridine crosslinking agents, metal chelate crosslinking agents, epoxy crosslinking agents, and isocyanate crosslinking agents.
In the adhesive composition, the content of the crosslinking agent is not particularly limited, but is, for example, 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the adhesive agent. When the content is 0.1 parts by mass or more, the shape retention property tends to be less likely to decrease. Furthermore, when the content is 10 parts by mass or less, high adhesive force tends to be easily exhibited.
The adhesive composition may include other additives such as a solvent such as an organic solvent, an inhibitor that suppresses the progress of crosslinking, an adhesion giving resin (tackifier), an ultraviolet (UV) absorber, a light stabilizer (HALS), an antioxidant, an infrared absorber, dyes and pigments.
The mode of use of the above-mentioned adhesive composition is not limited. The mode of use of the above-mentioned adhesive composition can be appropriately selected depending on the purpose.
When the adhesive composition is designed to produce haze at high temperatures, the adhesive composition can be used suitably, for example, for window materials, light-transparent roof material, and the like, because direct sunlight can be softened during high temperatures in summer and sunlight can be allowed to enter during low temperatures in winter.
On the other hand, when the adhesive composition is designed to produce haze at low temperatures, for example, when the adhesive composition is applied to window glass, the window glass functions as frost glass in a condition in which the temperature is relatively low and the amount of sunlight is low, such as in the morning or at night, while the window glass becomes transparent and sunlight can be allowed to enter the room efficiently when the temperature rises with increase in the amount of sunlight during daytime.
Furthermore, the above adhesive composition can allow designs such as a character, a symbol, a pattern, a figure, and a picture to appear or disappear when haze appears or disappears at high temperatures due to heat sources such as lighting, solar radiation, or air temperatures, and can give excellent display properties (designs such as a character and a symbol) and decorative properties (designs such as a pattern, a figure, and a picture) to an object including an adhesive layer. Therefore, the adhesive composition can be suitably used, for example, for decoration of light covers, for decoration of light-transparent base materials of window materials and light-transparent roof materials, and for display of light-transparent base materials such as window materials and light-transparent roof materials.
The adhesive sheet includes an adhesive layer made of an adhesive composition.
As described above, the temperature-sensitive dimming liquid laminated body of Patent Document 1 requires a dedicated structure body for maintaining the shape of the temperature-sensitive dimming liquid. Therefore, when installing it later on existing windows or roofs, large-scale construction work such as replacing the entire window is required, which makes it difficult to be introduced.
In contrast, it is advantageous that adhesive sheets do not require a dedicated structure body to maintain their shape, and can be easily installed by simply pasting them onto existing windows or roofs, and can autonomously change the degree of cloudiness depending on temperatures.
A thickness of the adhesive layer is not particularly limited, but is preferably 5 μm or more and 1 mm or less, and more preferably 10 μm or more and 100 μm or less. Note here that the thicker the adhesive layer is, the more the dimming function tends to be exhibited with addition of a small amount of temperature-sensitive fine particles. The thinner the thickness is, the more temperature-sensitive fine particles tend to need to be added in order to exhibit the light dimming function.
The haze value of the adhesive layer at 40° C. is preferably higher by 10% or more than the haze value at 23° C. This tends to make it easier to visually recognize changes in degree of cloudiness depending on temperature.
The haze value of the adhesive layer at 23° C. is preferably 10% or less, and more preferably 5% or less. The lower limit of the haze value at 23° C. is not particularly limited. Furthermore, the haze value of the adhesive layer at 40° C. is preferably 12% or more, more preferably 20% or more, and still more preferably 30% or more. The upper limit of the haze value at 40° C. is not particularly limited, but is, for example, 70% or less, or 50% or less.
The transmittance of solar radiation at 40° C. is preferably lower by 10% or more than the transmittance of solar radiation at 23° C.
The transmittance of solar radiation of the adhesive layer at 23° C. is preferably 50% or more, more preferably 60% or more, and still more preferably 70% or more. The upper limit of the transmittance of solar radiation at 23° C. is not particularly limited, but is, for example, 95% or less, or 85% or less. Furthermore, the transmittance of solar radiation through the adhesive layer at 40° C. is preferably 70% or less, more preferably 60% or less, and still more preferably 50% or less. The lower limit of the transmittance of solar radiation at 40° C. is not particularly limited.
The peel strength of the adhesive layer against stainless steel (SUS) at 23° C. is preferably 1.0 N/25 mm or more. Furthermore, the peel strength against polyethylene terephthalate (PET) at 23° C. is preferably 1.0 N/25 mm or more. Note here that in this description, peel strength is a value measured by the method described in Examples below.
The adhesive sheet may include a base material sheet. The base material constituting the base material sheet is not particularly limited as long as it is a light-transparent base material. As a base material, for example, PET such as corona treated PET, untreated PET, highly transparent PET, annealed PET, UV cut PET, heat shielding PET, anti-fog PET, hard coat PET, blasted PET; transparent PI, and the like, can be used.
The adhesive layer may be formed only on one surface of the base material sheet, or may be formed on both surfaces. Alternatively, an adhesive layer may be formed on one surface of the base material sheet, and an adhesive layer other than the adhesive layer described above may be formed on the other surface.
A release sheet may be laminated on the surface of the adhesive layer in the same manner as the base material sheet.
The adhesive sheet can be produced by a usual method using the adhesive composition described above. For example, a method may be used in which a coating solution prepared by adding a solvent agent and a crosslinking agent to an adhesive composition as necessary is applied to a base material sheet using a coater or the like, and then dried by heating or the like to form an adhesive layer.
Examples of the coater include a knife coater, roll coater, calendar coater, comma coater, and the like. Furthermore, depending on the coating thickness and the viscosity of the coating liquid, gravure coater, rod coater, and the like may also be used.
Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited to these Examples.
Hereinafter, various chemicals used in Examples will be collectively described.
A side chain crystalline monomer, a polyfunctional monomer, and an initiator were added to the reaction vessel in the proportions shown in Table 1. The mixture in the reaction vessel was stirred with a spatula to uniformly mix. Next, an aqueous medium and an emulsifier in the proportions shown in Table 1 were added to the reaction vessel to obtain a mixed solution. Water was used as the aqueous medium. The aqueous medium was added so that the ratio of the mass of the side chain crystalline monomer to the total mass of the side chain crystalline monomer and the mass of the aqueous medium in the mixed solution was 40% by mass. Furthermore, the mixed solution was stirred for 5 minutes at 7500 rpm using a homogenizer manufactured by IKA (main body: T 25 digital ULTRA-TURRAX, shaft generator: S25N-25F) to form monomer components into particles. Finally, nitrogen was introduced into the mixed solution, bubbled, and air (oxygen) in the mixture was removed, and then heated and stirred at 67° C. for 2 hours and at 80° C. for 2 hours to polymerize the monomer components. Then, the aqueous medium was removed from the generated fine particles by suction filtration and vacuum drying to obtain temperature-sensitive fine particles 1.
Temperature-sensitive fine particles 2 were obtained in the same manner as in the method for producing the temperature-sensitive fine particles 1, except that the mixed solution was stirred for 5 minutes at 14,000 rpm using a homogenizer.
Temperature-sensitive fine particles 3 were obtained in the same manner as in the method for producing the temperature-sensitive fine particles 1, except that the mixed solution was stirred for 5 minutes at 6800 rpm using a homogenizer.
Temperature-sensitive fine particles 4 were obtained in the same manner as in the method for producing the temperature-sensitive fine particles 1, except that the mixed solution was stirred for 3 minutes at 5500 rpm using a homogenizer.
The particle size distribution of the temperature-sensitive fine particles was measured using a laser diffraction particle size distribution meter “Mastersizer 3000” manufactured by Malvern. In the particle size distribution, the particle diameter corresponding to a cumulative volume frequency of 50% calculated from the smaller particle diameter of the temperature-sensitive fine particles is defined as the “average particle diameter”, and the particle diameter corresponding to a cumulative volume frequency of 90% is defined as the “D90 particle size.”
The results are shown in Table 1.
Using a DSC (differential scanning calorimeter) manufactured by Seiko Instruments Inc., the melting point of the temperature-sensitive fine particles was measured from the temperature at the top of the endothermic peak measured in the range of −30° C. to 100° C. at a sweep rate of 10° C./min. The results are shown in Table 1.
Monomers were charged into the reaction vessel in the proportions shown in Table 2. A solvent agent (ethyl acetate/methyl ethyl ketone=90/10 (mass ratio)) was added to the reaction vessel to dilute the monomer so that the monomer concentration was 38% by mass. Next, the diluted monomer solution was stirred and heated while nitrogen was introduced into the diluted monomer solution and bubbled. When the liquid temperature reached 55° C., an initiator was added to the diluted monomer solution in the proportions shown in Table 2. Furthermore, after heating and stirring the liquid in the reaction vessel at 55° C. for 4 hours, the temperature of the oil bath was raised to 80° C. When the liquid temperature exceeded 70° C., a promoter was added to the reaction solution in the proportions shown in Table 2. Finally, heating and stirring were carried out at 80° C. for 2 hours to obtain an adhesive agent.
Measurement was carried out by gel permeation chromatography (GPC), and the obtained measured value was converted into polystyrene. The results are shown in Table 2.
Using a dynamic viscoelasticity measuring device “HAAKE MARS III” manufactured by Thermo Scientific, tan 6 (loss tangent) was measured at 20 Hz, 5° C./min, and in a temperature increasing process from −100° C. to 100° C. The glass transition temperature (Tg) was obtained from the peak temperature of tan 6 obtained. The results are shown in Table 2.
The obtained temperature-sensitive fine particles were added to a solvent agent (heptane) and stirred with a spatula to obtain a dispersion solution. The dispersion solution was added to the obtained adhesive agent. The temperature-sensitive fine particles and the adhesive agent were added in the proportions shown in Tables 3 and 4, and the solvent agent was added in a proportion such that the solid content concentration was 30% by mass.
An inhibitor was added to this adhesive composition in the proportions shown in Tables 3 and 4, and the obtained mixture was stirred uniformly with a spatula, and then a crosslinking agent was added in the proportions shown in Tables 3 and 4. The adhesive composition was applied to the corona-treated surface of a PET film (thickness: 100 μm) using a bar coater. Thereafter, the PET film was dried by heating at 110° C. for 3 minutes in a hot air circulating oven to obtain adhesive sheets (Examples 1 to 7) having an adhesive layer (thickness: 40 μm) made of a crosslinked adhesive composition.
The refractive indices at 23° C. and 40° C. of the obtained temperature-sensitive fine particles and adhesive agent was measured using an automatic refractometer “Abbemat 350” manufactured by Anton Paar. The results are shown in Tables 3 and 4.
The haze value of the adhesive layer of the obtained adhesive sheet at 23° C. and 40° C. was measured in accordance with ASTM D1003 using a spectrophotometer “CM3600” (C light source) manufactured by Konica Minolta, Inc. With ITO glass as a reference, measurement was carried out by pasting an adhesive sheet on the ITO glass surface. The results are shown in Tables 3 and 4.
The 180° peel strength of the obtained adhesive sheets of Examples 1 to 4 against stainless steel (SUS) or polyethylene terephthalate (PET) at 23° C. was measured in accordance with JIS Z0237. Specifically, the adhesive sheet was pasted to SUS or PET, left to stand for 20 minutes, and then peeled off by 180° using a load cell at a speed of 300 mm/min. As the SUS, plate-shaped SUS304 was used. As PET, an untreated film having a thickness of 25 μm was used. The adhesive sheet was attached to SUS or PET by moving a 2 kg roller back and forth 5 times on the adhesive sheet. The results are shown in Table 3.
For the obtained adhesive sheets of Examples 2 and 5 to 7, transmittance of solar radiation at 23° C. and 40° C. were measured using a spectrophotometer “V770DS” manufactured by JASCO Corporation in accordance with JIS A5759:2016 6.5. Since the measurement was carried out after warming to 40° C., ITO glass (GMT-100-12, manufactured by Geomatec) having a thickness of 1.1 mm was used as the object to which the adhesive sheet was attached. Specifically, a test piece was prepared by attaching an adhesive sheet on one surface of the ITO glass. At 23° C. and 40° C. (the surface temperatures of the ITO glass, measured by a contact surface thermometer), the spectral transmittance of each wavelength from 300 to 2500 nm was measured using a spectrophotometer with the glass surface of the test piece facing the light source. The transmittance of solar radiation was calculated based on the relative spectral distribution of solar radiation as specified in JIS A5759:2016. The results are shown in Table 4.
The heat shielding properties of the obtained adhesive sheets of Examples 2 and 5 to 7 were evaluated as shown in
As is apparent from Table 3, according to Examples 1 to 4, it can be seen that the adhesive layers of Examples 1 to 4 having the above-mentioned predetermined configuration can autonomously change the degree of cloudiness depending on the temperature. Therefore, from Examples 1 to 4, it can be seen that window materials and light-transparent roof materials including the above-mentioned adhesive layer can autonomously change the degree of cloudiness depending on temperatures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-048301 | Mar 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/011833 | 3/24/2023 | WO |
