KR101794710B1 - Transparent and heat-insulating material including polymer capsule and method for preparing the same - Google Patents

Abstract

Disclosed is a transparent insulating material comprising a transparent thermally insulating resin layer containing a polymeric capsule and an optical resin, and a method for producing the same. According to the transparent heat insulator, radiant heat transmission of solar radiation coming from the outside can be reduced, heat emission of the inside can be prevented, and at the same time, transparency is high. Further, the size of the capsule contained in the transparent insulating film can be easily controlled, and the manufacturing process is simple and easy. Further, the light transmittance and the heat insulating property of the transparent heat insulator can be easily controlled.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a transparent insulator including a polymer capsule,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent insulation material including a polymer capsule and a method of manufacturing the same.

Much effort has been made to reduce the cooling and heating costs of buildings, especially glass wall buildings, which are being built many times in recent years.

In glass-walled buildings, energy consumption accounts for 24% of total energy consumption, with an average of 30% of window heat loss and over 7% of total energy loss. The heat transfer coefficient of the window is more than 5 times larger than the outer wall or roof of the building, so that the heat loss is the highest. Furthermore, since solar radiation penetrates through the window during the summer season, it causes a cooling load during cooling, resulting in a cooling load of 66%. During the winter, the heating heat escapes through the glass window during heating, % Of the heating load is lost through the window.

Therefore, much attention has been focused on improving the heat rejection rate of building windows. In order to solve this problem, a method of interrupting the heat flow by connecting the inside and the outside of the frame to a nonmetallic insulating material having a low thermal conductivity has been used. Also, an air cap may be used to prevent the external cooling air from being transmitted to the window.

In addition, efforts have been made to increase the thermal insulation performance by injecting inert fill gas such as air, argon, and krypton directly into the double-layer glass.

However, according to the studies of the present inventors, it has been found that the method of directly injecting the air cap or the conventional inert fill gas is difficult and difficult to secure related technologies such as durability when sealing the fill gas, gas mixing method, There is a problem.

On the other hand, conventionally, there is disclosed a technique of extruding a mixture of a polyvinyl chloride resin, a microsilica capsule and a plasticizer to produce a film-like glass heat insulating material (Patent Document 1).

However, according to the studies of the present inventors, there is a problem that the method can not control the size of the microsilica capsule which affects the transparency and the heat insulating property of the glass, so that it is difficult to control the transparency and the heat insulating property, and the manufacturing process is complicated.

Patent Document 1: Korean Patent No. 0870908

Embodiments of the present invention, in one aspect, provide a transparent insulating material having excellent heat insulating properties capable of reducing radiant heat transmission of solar radiation radiated from the outside, .

In embodiments of the present invention, in another aspect, there is provided a transparent insulating material which can easily control the size of capsules contained in transparent insulating material, is simple and easy to manufacture, and is suitable for mass production, and a method for producing the same.

In embodiments of the present invention, in another aspect, there is provided a method of easily controlling transparency and thermal insulation of a transparent insulation.

In an exemplary embodiment of the present invention, the transparent heat insulating material includes a transparent heat insulating resin layer, and the transparent heat insulating resin layer comprises an optical resin; And a polymer capsule.

In an exemplary embodiment of the present invention, there is provided a method of manufacturing the transparent insulating material, comprising the steps of: preparing a polymer capsule; And mixing the polymer capsules with an optical resin.

According to the embodiments of the present invention, in one aspect, a transparent insulating film having excellent heat insulating properties capable of reducing radiant heat transmission of solar radiation incoming from the outside, .

Further, according to the embodiments of the present invention, in another aspect, it is possible to easily control the size of the capsules contained in the transparent heat insulating film, to facilitate the manufacturing process, to reduce the manufacturing cost, and to be suitable for mass production.

Further, according to the embodiments of the present invention, in another aspect, the light transmittance and the heat insulating property of the transparent heat insulating film can be easily controlled.

1 is a schematic view showing a transparent insulating film according to one exemplary embodiment of the present invention.
2 is a SEM photograph of a spherical polymer capsule prepared in an embodiment of the present invention.
3 is an actual photograph of a transparent film (0 wt% of polymer capsules, Fig. 3A) and a transparent heat insulating film (containing 30 wt% of polymer capsules, Fig. 3B) of the comparative example of the present invention.
4 is a graph showing the results of measurement of the transmittance of the transparent insulating film of Example 3 of the present invention and the transparent film of the comparative example using a UV-Vis spectrophotometer. 4, the X-axis is the wavelength (unit: nm) and the Y-axis is the transmittance (unit:%).
5 is a graph showing the results of measurement of the thermal conductivity of the transparent heat insulating film of Comparative Examples and Examples of the present invention using a thermal conductivity tester. 5, the X axis is the capsule content (unit: wt%) and the Y axis is the thermal conductivity (unit: W / mK).

Hereinafter, exemplary embodiments of the present invention will be described in detail. It is to be understood that the features of the following exemplary embodiments may be applied individually or in combination, and that the present invention is not limited to any one embodiment.

In this specification, transparent adiabatic means that transparency and heat insulation are simultaneously exhibited. For example, transparency is that the light transmittance in the visible light region is 60% or more based on quartz, and the thermal conductivity is 0.15 W / mk or less.

As used herein, an optical resin means a resin having light transmittance and having a light transmittance in the visible light range of 60% or more, or 90% or more, or 92% or more, or 92-98% in terms of quartz.

Exemplary embodiments of the present invention provide a transparent insulating material such as a transparent insulating film including a transparent insulating resin layer. The transparent heat insulating resin layer includes an optical resin and a polymer capsule.

In one exemplary embodiment, there is provided a transparent heat insulating film (or sheet) comprising a substrate and a transparent heat insulating resin layer formed on the substrate.

1 is a schematic view showing a transparent insulating film according to one exemplary embodiment of the present invention.

As shown in Fig. 1, a transparent heat insulating resin layer including an optical resin 20 and a polymer capsule 10 is formed on a base material 30. Fig.

In an exemplary embodiment, the optical resin is a resin exhibiting light transmittance that can be used in a transparent heat insulating film, and has a light transmittance in a visible light range of 60% or more, preferably 90% or more, Or more, or 92% to 98%.

As the optical resin having the light transmittance, various components can be used. For example, resins having the above-mentioned light transmittance among resins such as polyacrylic, polyolefin, polyurethane, and polyepoxy resins can be used. The optical resin may be a photo-curing resin or a thermosetting resin.

In an exemplary embodiment, the optical resin should be one that does not dissolve the polymer capsules. The polymer capsules are dispersed in such an optical resin, preferably without agglomerate, more preferably with a random size, to form a transparent heat insulating resin layer.

In an exemplary embodiment, the polymer capsule is made of a polymer and may include voids therein. For example, at least some or all of the polymer capsules may comprise a void space within the capsule and a polymer membrane surrounding the void space. Here, the empty space may be filled with gas.

In a non-limiting example, the polymer capsules may contain air (or an air layer) or may contain an inert gas (or gas layer), such as akgon, krypton, or the like, with a low thermal conductivity.

When the polymer capsules are contained in the transparent heat insulating film, the thermal conductivity is lowered as compared with that before the injection, and the radiant heat transmission of the solar radiation energy introduced from the outside is reduced to improve the blocking rate of radiant heat rays. It can exhibit an adiabatic performance capable of reducing the emission of heating heat.

Since the polymer capsules are made of a polymer, their size can be easily controlled unlike inorganic capsules. The polymer capsules have an influence on the transparency of not only the heat insulation but also the transparency of the transparent heat insulating film. If the size of the polymer capsules can be controlled, the heat insulating property and transparency of the transparent heat insulating film can be easily controlled.

The transparent heat insulating film comprising the polymer capsule together with the optical resin has a light transmittance of 60% or more, preferably 63% or more, more preferably 70% or more, in terms of quartz in the visible light region.

In addition, the transparent heat insulating film including the polymer capsule together with the optical resin can exhibit an excellent heat insulating performance with a light transmittance as described above and a thermal conductivity of less than 0.2 W / mk, preferably 0.02 to 0.15 W / mk . Further, the transparent heat insulating film has no optical distortion. Accordingly, it can be attached to a glass window or used instead of a glass window. The optical distortion can be evaluated by measuring the haze. The haze can be measured, for example, via a haze meter or spectrophotometer, and in one exemplary embodiment, the transparent adiabatic film can exhibit a haze of less than or equal to 0.1%.

The polymer used in the polymer capsule should be selected so as to satisfy the light transmittance in consideration of the optical resin used together.

In an exemplary embodiment, the polymer capsule preferably has a refractive index difference of 0 to 0.1 in optical resin in terms of light transmittance and haze. The refractive index can be measured using an Abbe refractometer, for example. The transparency of the transparent insulation can be controlled through the difference in refractive index.

In an exemplary embodiment, the polymer of the polymer capsule and the optical resin have the above-described refractive index difference, and may be, for example, the following. That is, the polymer of the polymer capsule may be selected from among polyacrylic, polystyrene, polyurethane, polycarbonate, polyolefin, and polyimide polymers such as poly (methyl methacrylate).

In an exemplary embodiment, the content of the polymer capsules in the optical resin layer may be more than 0% by weight and 90% by weight or less based on 100% by weight of the polymer capsules and the optical resin. In order to increase the heat insulation performance, it is advantageous to increase the content of the polymer capsules, but the transparency can be reduced. Conversely, if the content of the polymer capsules is reduced, the transparency may increase but the heat insulating performance may be poor.

In view of the heat insulating properties (for example, thermal conductivity of 0.02 to 0.15 W / mk) and the transparency (for example, the light transmittance in the visible light range is 60% or more based on quartz) of the transparent heat insulating film, the content of the polymer capsules is Is preferably 0.1 wt% or more and 60 wt% or less based on 100 wt%. In addition, even with the inclusion of the polymer capsules, excellent heat insulating performance (for example, a thermal conductivity of 0.02 to 0.15 W / mk) can be ensured while the transparency is substantially the same (within 1% difference in transparency) The content of the polymer capsules is more preferably 10% by weight or more and 50% by weight or less based on 100% by weight of the total of the polymer capsules and the optical resin.

In an exemplary embodiment, the substrate is used as a support for forming a transparent heat insulating resin layer.

In an exemplary embodiment, the transparent heat insulating material is a transparent heat insulating film, and the transparent heat insulating film may include a substrate and a transparent heat insulating resin layer, and after forming the transparent heat insulating resin layer, the substrate may be removed and used.

In an exemplary embodiment, when the transparent insulating film includes a substrate, a transparent heat insulating resin layer may be formed on one side or both sides of the substrate, or a method of forming a transparent heat insulating resin layer between two substrates may be possible Do.

In an exemplary embodiment, the light transmittance of the substrate is such that the light transmittance in the visible light region is at least 60% of the quartz. For example, a transparent substrate such as glass or polyethylene terephthalate can be used as the substrate.

On the other hand, exemplary embodiments of the present invention provide a method of manufacturing the above-described transparent insulation.

In the above-described manufacturing method, a polymer capsule is first prepared; And mixing the polymer capsules with an optical resin.

In an exemplary embodiment, the manufacturing method is a manufacturing method of a transparent insulating film, comprising the steps of: preparing a polymer capsule; And mixing the polymer capsules with an optical resin and coating the mixture on a substrate to form a transparent heat insulating resin layer formed on the substrate and the substrate.

In an exemplary embodiment, the method may further comprise removing the substrate after the coating.

In an exemplary embodiment, the polymer capsule manufacturing can be done in a variety of ways.

In a non-limiting example, the method comprises mixing and heating a surfactant, a dispersant, an organic solvent, a radical polymerizable monomer, and a radical polymerization initiator to provide a polymeric capsule; And mixing the optical resin and the polymer capsules and coating the mixture on the substrate.

Each component will be described in detail below.

When the surfactant is dissolved in the organic solvent, spherical reverse micelles are formed. Also, the size of reverse micelles formed in the solution can be controlled according to the ratio of the surfactant. Therefore, the surfactant should be used in an amount capable of forming reverse micelles. Since the formation of reverse micelles affects the formation of the polymer capsules, the size of the polymer capsules can be controlled by controlling the size of the reverse micelles as described above.

The organic solvent may be a solvent for forming reverse micelles, for example, a polar organic solvent such as methanol.

As the surfactant, for example, sodium octylsulfosuccinate sodium salt (AOT) or the like can be used.

The initiator is an initiator used in radical polymerization. Such radicals meet a small amount of the monomer dissolved in the solution to initiate the reaction. The disclosed radicals are grown in solution to have surface activity from the moment the balance between the hydrophilic portion of the initiator and the hydrophobic portion of the monomer is adequately maintained.

As the initiator, for example, azobisisobutyronitrile (AIBN) and the like can be used.

With respect to the dispersant, the oligoradical radicals grown from the initiator radicals after polymerization initiation are separated from the continuous phase and precipitated as the size increases. The precipitated pre-particles are stabilized by the dispersant and as the size of the particles increases, they can absorb more monomers and grow as particles. As such a dispersing agent, for example, polyvinylpyrrolidone (PVP) or the like can be used.

On the other hand, the radical polymerizable monomer continuously bonds with the radical generated by the initiator upon polymerization and grows into a polymer capsule. As the monomer, for example, methyl methacrylate (MMA) may be used.

In an exemplary embodiment, it is preferable to further include performing freeze-drying after the polymer capsule polymerization. Lyophilization can prevent the capsules from clumping in the step of washing and drying the capsules, thereby advantageously dispersing the capsules uniformly without aggregation (aggregation) in the optical resin.

More specifically, in one exemplary embodiment of the method, mixing a surfactant, a dispersant, and an organic solvent; Adding a radical polymerization monomer and a radical polymerization initiator to the mixture and heating to polymerize the polymer capsules; Lyophilizing the polymer capsules; Mixing the optical resin and the lyophilized polymer capsules, and coating the mixture on the substrate.

In an exemplary embodiment, if the optical resin is a photocurable or thermosetting resin, curing may be performed by applying light (e.g. UV lamp) or heat after coating.

In an exemplary embodiment, according to the above manufacturing method, the size (average size) of the polymer capsule can be easily controlled.

That is, in the case of the radical polymerization method, for example, the uniformity of the capsules can be controlled according to the synthesis time, so that the capsules having a uniform size as well as the capsules having a random size can be produced. That is, in an exemplary embodiment, when polymer capsules are polymerized, capsules are formed after 2 hours of reaction, and capsules of uniform size may be formed. When 7 hours have elapsed after the reaction, capsules are formed at a random size . Also, if the reaction time is set to 10 hours or more, the capsules having a random size can be formed into capsules having a uniform size in order to achieve equilibrium. By controlling the polymerization time of the polymer capsules, uniform size capsules as well as random size capsules can be polymerized.

Accordingly, the average particle size of the polymer capsules can be variously varied, for example, from 0.1 to 150 mu m.

In an exemplary embodiment, the polymer capsules preferably have a random particle size. In the case of polymer capsules of uniform size (i.e., where only capsules with a certain average particle size are present), polymer capsules of a more random size (i.e., capsules having two or more different average particle sizes are mixed ) Has a low thermal conductivity and is excellent in terms of heat insulation. When the polymer capsules having different sizes (average sizes) are mixed, more polymer capsules are contained in the same volume, so that the thermal conductivity is low. A low thermal conductivity in terms of adiabatic means better insulation. Therefore, in the case of the capsules having the same content (when the polymer capsules having two or more different average particle sizes are mixed), the transparency is similar to that of the capsules having the uniform size, .

In an exemplary embodiment, additives may be further included in the production of the transparent insulating film.

As the additive, for example, a metal material or a ceramic material may be used to block light by reflecting light or absorbing light. When the additive for light reflection or light absorption is used as described above, it is possible to maximize heat shielding by reflecting or absorbing light in addition to the heat insulation performance of the above-mentioned transparent heat insulation film. Such an optical additive or light absorber additive may be contained in the transparent heat insulating resin layer of the transparent heat insulating film together with the polymer capsules or may be formed as a separate layer.

That is, in an exemplary embodiment, the transparent heat insulating film includes a substrate, a transparent heat insulating resin layer formed on one side or both sides of the substrate, a light insulating film formed on the transparent heat insulating resin layer or a substrate on which the transparent heat insulating resin layer is not formed And may further comprise a layer made of a light-absorbing additive or a light-absorbing additive.

The additive or additive layer is also added / formed so as not to impair transparency. As such additives, nanoparticles such as ceramic nanoparticles or metal nanoparticles can be used.

The transparent insulating film manufactured according to the exemplary embodiments of the present invention encapsulates the polymer capsules to have a high heat insulating performance, so that it is possible to reduce the radiant heat transmission of the incoming solar radiation energy, At the same time, the transparency of the transparent heat insulating film is high. Therefore, it can be very usefully used as a heat block or an insulating film of a building (particularly a glass wall building), a house, an automobile or the like.

Hereinafter, specific embodiments according to embodiments of the present invention will be described in more detail. It should be understood, however, that the invention is not limited to the embodiments described below, but that various embodiments of the invention may be practiced within the scope of the appended claims, It will be understood that the invention is intended to facilitate the practice of the invention to those skilled in the art.

[Examples and Comparative Examples]

Manufacture of polymer capsules

(MMA) (10 wt%), dioctyl sulfosuccinate sodium salt (AOT) (0.45 wt%), poly (vinylpyrrolidone), PVP (4 wt%), 2,2'-azobisisobutyronitrile (AIBN) (0.1 wt%), and methanol (85.45 wt%) were mixed at a weight ratio of 10: 0.45 : 4: 0.1: 85.45.

Specifically, the polymer capsules were purged with argon in a three-neck flask, and AOT (0.45 wt%, 0.9 g), PVP (4 wt%, 4 g) and MeOH (85.45 wt%, 108 mL) Lt; RTI ID = 0.0 > rm < / RTI > for about 10 minutes. MMA monomer (10 wt%, 10 m) and AIBN (0.1 wt%, 0.1 g) were added to the mixed solution and stirred at a rate of 400 rpm at 58 ° C. When the reaction is initiated, the clear solution becomes cloudy. After 2 hours of reaction, the MMA capsules begin to form. At this time, a uniform sized crumpled capsule is formed. When the reaction is completed for 7 hours, a random sized capsule is formed do. Also, if the reaction time exceeds 10 hours after the reaction, the capsules of random size are formed in a uniform size to maintain a stable state. The PMMA capsules thus obtained are washed three times using DI water and centrifuged. This is to wash unreacted monomers and solvents. The obtained PMMA capsules can be obtained as a fine powder through freeze-drying.

2 is a SEM photograph of a spherical polymer capsule prepared in an embodiment of the present invention.

As shown in FIG. 2, it can be confirmed that a spherical polymer capsule having an average particle size of 7 to 20 μm was formed. For reference, the capsule was adjusted to have a random size as shown in FIG.

Manufacture of transparent adiabatic film

(Comparative Example), 10 wt% (Example 1), 20 wt% (Example 2) and 30 wt% (Example 3) were prepared in an optical resin (acrylic resin) ), Respectively.

The refractive index of the polymer capsule was 1.49361 as measured using an Abbe refractometer, and the refractive index of the optical resin was 1.5

On the other hand, a piece of PET film is prepared, and the mixture in which the optical resin and the polymer capsules are mixed is dropped to the prepared PET film and coated using a bar coater. The bar coater conditions are adjusted by controlling the coating thickness to 80 탆 and the coating speed to 4 mm / s.

The prepared film was irradiated for 2 minutes through a UV lamp to cure the film.

3 is an actual photograph of a transparent film (0 wt% of polymer capsules, Fig. 3A) and a transparent heat insulating film (containing 30 wt% of polymer capsules, Fig. 3B) of the comparative example of the present invention.

As shown in FIG. 3, even when a polymer capsule was included in comparison with the case where an optical resin was used alone, no light distortion was observed as a result of the haze measurement.

4 is a graph showing the results of measurement of the transmittance of the transparent insulating film of Example 3 of the present invention and the transparent film of the comparative example using a UV-Vis spectrophotometer. The baseline is based on a quartz plate, the comparative example shows a PET film, and Example 3 shows a UV transmittance of a PET film + optical resin + 30 wt% polymer capsules. 4, the X-axis is the wavelength (unit: nm) and the Y-axis is the transmittance (unit:%).

Fig. 4 shows that even when the polymer capsules are contained up to 30 wt%, the difference in transmittance is almost the same within 1%.

The thermal conductivity of the transparent heat insulating films of the comparative examples and examples of the present invention was measured three times using a thermal conductivity tester to obtain an average value.

Polymer capsule content Thermal conductivity (W / mK) Average value 0 wt% (substrate / optical resin) 0.18 0.18 10wt%
(Substrate / optical resin + polymer capsule 10wt%) 0.16 0.15 0.15 0.155 20wt%
(Substrate / optical resin + polymer capsule 20wt%) 0.13 0.13 0.131 0.129 30wt%
(Substrate / optical resin + polymer capsule 30wt%) 0.10 0.10 0.11 0.11

5 is a graph showing the results of measurement of the thermal conductivity of the transparent heat insulating film of Comparative Examples and Examples of the present invention using a thermal conductivity tester. 5, the X axis is the capsule content (unit: wt%) and the Y axis is the thermal conductivity (unit: W / mK).

As can be seen from FIG. 5, it can be confirmed that the thermal conductivity decreases (the heat insulating performance increases) as the content of the polymer capsules increases.

Claims (4)

As a transparent insulating material,
Wherein the transparent heat insulating material comprises a transparent heat insulating resin layer,
Wherein the transparent heat insulating resin layer is made of an acrylic optical resin having a light transmittance in a visible light range of 90% or more based on quartz; And a polymethyl methacrylate polymer capsule,
The refractive index difference between the polymethyl methacrylate polymer capsules and the acrylic optical resin measured by an Abbe's refractive index meter is 0 to 0.1,
The polymethylmethacrylate polymer capsules are random-sized polymethylmethacrylate polymer capsules having an average particle size of 7 to 20 탆 or less and are a mixture of polymethylmethacrylate polymer capsules having two or more different average particle sizes Lt; / RTI &
The content of the polymer capsules is 20% by weight or more and 30% by weight or less based on 100% by weight of the total of the polymer capsules and the optical resin,
Wherein the transparent heat insulating material has a thermal conductivity of 0.02 to 0.15 W / mk.
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