KR101955817B1 - Composite structure and method of manufacture the same - Google Patents

Abstract

The present invention relates to a composite structure and a production method thereof. The composite structure of the present invention comprises a composite layer including a hydrogel having a low critical solution temperature (LCST) and a hydrophobic substance, and controls opening and closing of a pore according to the temperature. Accordingly, by promoting or suppressing vaporization of water, when the composite structure is applied to an outer wall of a building, a device and the like, the internal temperature thereof can be cooled.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a composite structure,

The present invention relates to a composite structure and a method of manufacturing the same, and more particularly, to a hydrogel having an LCST and a complex structure including a hydrophobic substance and a method of manufacturing the same.

As the global warming phenomenon deepens, the earth is getting warmer. Especially in the summer, the temperature is gradually increasing year by year, and therefore, the amount of cooling equipment used to cool the interior of the building is continuously increasing. Most cooling units use air-powered air-conditioners, which have experienced several local power failures over the past few years, exceeding their power usage limits. As a result, researchers are studying ways to reduce power consumption by developing technologies that cut the heat from the sun or lower the internal temperature than the ambient temperature without power consumption of the building itself.

Cooling techniques applied to the outer walls of buildings to lower the room temperature include methods of adhering a heat insulating film to a window, spraying water on a roof, and applying insulation to an outer wall of a building. However, in the method of adhering the heat insulating film or the heat insulating material, when the room temperature which has risen due to the high temperature of one day is at night, it is not transmitted to the outside due to the heat insulating material, and the room temperature is rather higher than the outside temperature. It is possible to block heat, but this problem is caused by low heat transfer efficiency. Another technique is spraying water on the rooftop, which is effective for cooling the room, so it is a good way to comfort the room temperature rather than using insulation. However, Is a consumed technology.

Also, a method has been developed in which the air introduced from the outside is cooled by passing through a radiating panel and supplied to the inside. It is a way to let a hot plate of hot air into the building through a gap in the building, and then place a plate in the space through which the air passes. A copyboard is usually a metal material and it radiates radiant energy constantly, making it feel colder than the surrounding area. For example, metal railing on a staircase in a building may feel colder than the surrounding area. This method can provide cooling effect without power consumption. However, the metal materials that emit radiant energy are very rare metals because they are very rare metals, and radiant energy always absorbs radiant energy from the ambient air, so there is a limit that can not be significantly lowered compared to the ambient temperature.

An object of the present invention is to provide a novel composite structure which can effectively cool the interior by applying it to a building or a device surface without power consumption.

The composite structure for one purpose of the present invention includes a water layer including an inner space in which water can be stored; And a hydrogel having an LCST and a composite layer comprising a hydrophobic substance, the hydrogel having the LCST includes a pore structure.

In one embodiment, the hydrogel having the LCST is selected from the group consisting of poly N-isopropylacrylamide, acrylic acid, acrylamide, 2-hydroxyethyl methacrylate ), Polymethyl methacrylate, vinyl pyrrolidinone, vinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylonitrile Polyacrylonitrile, PAN-methyl sulfonate, polysulfone, polycarbonate, poly ester, poly ethylene glycol, polypropylene glycol, glycol, polyvinyl alcohol, cellulose compound, and mixtures thereof.

In one embodiment, the hydrophobic material is selected from the group consisting of silicone, butadiene, chloroprene, isobutane, isopentane, isoprene, polyacrylate, styrene-butadiene butadiene, styrene-butadiene, acrylonitrile-butadiene, chlorosulphonated polyethylene, ethylene-propylene, ethylene-propylene-diene, At least one of fluorocarbon, epichlorohydrin, polydimethylsiloxane, urethane, and mixtures thereof may be used.

In one embodiment, the thickness of the composite layer may be less than 2 m.

In one embodiment, the composite structure may be applied to an exterior wall of a building or to a surface of a device requiring cooling.

A method for manufacturing a composite structure for another object of the present invention includes a first step of preparing a monomer solution by dissolving a monomer of a hydrogel having an LCST in a solvent; A second step of adding a crosslinking agent and an initiator to the monomer solution to prepare a mixed solution; A third step of preparing a hydrogel by cross-linking the mixed solution in a mold; A fourth step of mixing the hydrogel and the hydrophobic material solution to prepare a composite solution; And a fifth step of curing the composite solution.

In one embodiment, the initiator of the second step may be a photoinitiator or a photoinitiator.

In one embodiment, if the photoinitiator is added in the second step, liquid nitrogen may be used in the third step to form a pore structure in the mixed solution contained in the mold, followed by crosslinking reaction by irradiating UV.

In one embodiment, when the thermal initiator is added in the second step, heat is applied to the crosslinking reaction in the third step, and then cooling is used to form a pore structure in the hydrogel.

The present invention relates to a new composite structure applicable to a building or a device surface, and the composite structure has an effect of cooling the interior through vaporization of water without power consumption. Further, since the vaporization can be suppressed or promoted according to the temperature, the internal temperature control can be made more effective at a lower cost.

1 and 2 are views showing a composite structure according to an embodiment of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

The present invention relates to a novel composite structure utilizing the most efficient method for vaporizing water that a living body uses to lower body temperature and a manufacturing method thereof. Since water absorbs the surrounding heat when vaporized, the ambient temperature is lowered. By the same principle, living things sweat when they are hot, and body temperature can be controlled efficiently. The composite structure based on the thermosensitive hydrogel of the present invention using this principle is capable of lowering the surface temperature of the building by vaporizing the water that has been aggressively heated only when the temperature is above a predetermined temperature, Conversely, when the weather is below a certain temperature, vaporization can be suppressed as much as possible to preserve the stored water.

The composite structure of the present invention includes a water layer including an inner space in which water can be stored; And a hydrogel having an LCST and a composite layer comprising a hydrophobic substance, the hydrogel having the LCST includes a pore structure.

The hydrogel having the above-mentioned LCST has a feature that the volume is reduced while releasing the water that has been held at a certain temperature. This temperature is referred to as a low critical solution temperature (LCST), and the hydrogel having the LCST may be referred to as a thermosensitive hydrogel.

In one embodiment, the hydrogel having the LCST is selected from the group consisting of poly N-isopropylacrylamide, N, N-dimethyl-N-methacrylamidopropylammoniopropane sulfonate, N-methacrylamido propylammoniopropanesulfonate, acrylic acid, acrylamide, 2-hydroxyethyl methacrylate, polymethyl methacrylate, vinyl pyrrolidinone, ), Vinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylonitrile, PAN-methyl sulfonate, polysulfone (also referred to as " Polysulfone, Polycarbonate, Polyester, Polyethylene Glycol, Polypropylene Glycol, Polyvinyl Alcohol, Cells, Lawrence's (cellulose) may be at least one or more series, and mixtures thereof. Examples of the cellulose series include cellulose diacetate, Cuprophan, Hemophan, cellulose triacetate, cellulose acetate, chitosan, chitosan, Alginate, and the like. The hydrogel having the LCST may be a crosslinked polymer or a crosslinked polymer obtained by mixing them and may be a substance whose degree of swelling varies in response to stimulation of temperature, pH, light, electricity, and ions. In addition, the hydrogel having the LCST has a polar group such as an amine, a sulfide, a carboxyl, an epoxy, a hydroxyl, an ester, And a complex polymeric material formed through copolymerization. In particular, when synthesized by copolymerization, the LCST of the hydrogel having the LCST may be 10 ° C to 50 ° C. For example, the hydrogel having the LCST may be selected from the group consisting of poly N-isopropylacrylamide (pNIPAm), polyN, N-diethylacrylamide (pDEAM), poly Poly methyl vinyl ether (pMVE), poly N-ethylmethacrylamide (pNEMAM), poly 2-ethoxyethyl vinyl ether (pEOVE), poly- Poly-N-vinylcaprolactam (pNVCa), poly N-vinylisobutyramide (pNVIBAM) and poly N-vinyl-n- butyramide (pNVBAM) may be used. For example, the hydrogel having the LCST may be poly-N-isopropylacrylamide, acrylic acid, acrylamide, 2-hydroxyethyl methacrylate, Polymethyl methacrylate, vinyl pyrrolidinone, vinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylonitrile (also referred to as " Polyacrylonitrile, PAN-methyl sulfonate, polysulfone, polycarbonate, poly ester, poly ethylene glycol, polypropylene glycol, ), Polyvinyl alcohol, cellulose compound, and mixtures thereof, and poly (N-isopropylacrylamide) .

In the case of PNIPAm hydrogels, the swelling degree of the PNIPAm hydrogel is drastically lowered when the temperature is increased to 32 ° C to 34 ° C or more in the state of being swollen in water, so that the volume of the PNIPAm hydrogel may be shrunk and water may be released.

The hydrophobic substance may act to prevent evaporation of water as the outer wall of the skin. As the hydrophobic material, various rubber-like materials such as silicon-based materials may be used. Since the hydrophobic material itself has high mechanical properties, it can be used on the outer wall of a building. In addition, since the hydrogel has elasticity similar to that of the hydrogel, the interface can be maintained without detachment even if the volume of the hydrogel changes according to the temperature change.

In one embodiment, the hydrophobic material may be a rubbery material and may be selected from the group consisting of silicone, butadiene, chloroprene, isobutane, isopentane, isoprene, acrylonitrile Butadiene, acrylonitrile-butadiene, styrene-butadiene, polyacrylate, ethylene-propylene-diene, chlorosulphonated polyethylene, ethylene-propylene a cross-linking polymer such as ethylene-propylene, fluorocarbon, urethane, epichlorohydrin, polydimethylsiloxane, or the like, or a mixture thereof, and a mixture thereof One can be included. The hydrophobic substance may be a substance having Young's modulus value of 0.1 MPa to 100 MPa, which is related to the stretching property of the rubber.

On the other hand, when a hydrogel having LCST and PNIPAm together with methacrylate, which is a hydrophobic substance, together constitute a copolymer, the LCST becomes lower than 32 ° C to 34 ° C. On the other hand, hydrophilic properties such as acrylic acid Constituting the materials and copolymers results in higher LCST. Therefore, the temperature range in which the composite structure of the present invention can lower the temperature by releasing water can be freely set. Hydrogels having LCSTs of different chemical structures may also be used.

In one embodiment, the thickness of the composite layer may be less than 2 m. For example, the hydrogel having the LCST of the composite layer may have a thickness of 1 m or less.

In one embodiment, the hydrogel having the LCST of the composite structure may comprise pores. In one embodiment, the pores may be less than or equal to 2 m, for example less than or equal to 1 m.

In one embodiment, the composite structure may be applied to an exterior wall of a building. It can be applied to the surface of equipment requiring cooling such as factory equipment or equipment.

In one embodiment, when the composite structure is applied to a building exterior wall or a surface of a device requiring cooling, the water layer may be disposed in contact with the exterior wall of the building or the surface of the device.

The shape of the composite structure may include, but is not limited to, a transverse length of 5 m or less, a longitudinal length of 5 m or less, and a round or angular shape.

The present invention utilizes the heat of vaporization. When the new composite structure of the present invention is applied to a building surface or a device surface requiring cooling, the internal temperature can be cooled without power consumption.

The structure of the present invention includes a water layer in which water supplied through rainwater or the like is stored, water is always carried on the surface of the building by the water layer, and a hydrogel having a hydrophobic substance and an LCST And a composite layer included therein. When the weather is hot, ie when the temperature is above a certain temperature, the hydrogel with LCST will emit water and may shrink. As the hydrogel having the LCST shrinks, an empty space may be generated, thereby promoting the vaporization of water while changing the structure of the structure. On the other hand, when the weather is good, that is, when the temperature is lower than a certain temperature, the hydrogel having an LCST carries water, so that evaporation of water can be suppressed. In addition, since the hydrophilic material as well as the hydrogel having the LCST is included in the composite layer, evaporation of water in the cool weather can be suppressed to the utmost.

Since the composite structure of the present invention includes a complex layer of a hydrophobic substance and a hydrogel having an LCST, it is possible to control the temperature by regulating the vaporization by opening and closing the pores according to temperature similar to the epidermal tissue of the human body . The skin layer that protects the body from the hydrophobic substance and the hydrogel having the pore-forming LCST serve as the sweat glands to control the body temperature.

According to the present invention, it is possible to provide a structure having a cooling effect by utilizing the characteristics of a hydrogel having an LCST that releases water by reacting with a change in temperature and water vaporization.

A method for producing a composite structure according to the present invention includes a first step of preparing a monomer solution by dissolving a monomer of a hydrogel having an LCST in a solvent; A second step of adding a crosslinking agent and an initiator to the monomer solution to prepare a mixed solution; A third step of preparing a hydrogel by cross-linking the mixed solution in a mold; A fourth step of mixing the hydrogel and the hydrophobic material solution to prepare a composite solution; And a fifth step of curing the composite solution.

In one embodiment, the initiator of the second stage may be a photoinitiator or a heat initiator.

In one embodiment, if the photoinitiator is added in the second step, liquid nitrogen may be used in the third step to form a pore structure in the mixed solution contained in the mold, followed by crosslinking reaction by irradiating UV.

The crosslinking reaction may be carried out using a UV lamp, and the UV lamp may have a wavelength of 245 nm to 365 nm, and may have an output range of 1 to 40000 w.

In one embodiment, when the thermal initiator is added in the second step, heat is applied to the crosslinking reaction in the third step, and then a pore structure is formed in the hydrogel using liquid nitrogen.

The temperature in the case of subjecting the heat to the crosslinking reaction may be 10 ° C to 90 ° C.

In one embodiment, the fifth step may be to cure the composite solution at 30 ° C to 90 ° C to produce the composite structure.

In one embodiment, the monomer of the hydrogel having the LCST may be N-isopropylacrylamide.

In one embodiment, the hydrophobic material solution may comprise a silicone monomer and a curing agent.

In one embodiment, the cross-linking agent may be methylenebisacrylamide.

In one embodiment, the initiator may be IRGACURE or ammonium persulfate.

Hereinafter, embodiments of the present invention will be described in detail. However, the following examples are only a few embodiments of the present invention, and the present invention should not be construed as being limited to the following examples.

According to one embodiment, a hydrogel having the LCST of the present invention and a complex structure containing a hydrophobic substance were prepared. There are two methods for producing the composite structure.

Example 1: Preparation of composite structure 1 (Photoinitiator)

First, N-isopropylacrylamide (NIPAm) as a monomer was dissolved in water at a ratio of 20 wt%, and methylenebisacrylamide (MBA) as a crosslinking agent and IRGACURE, a kind of photoinitiator, The amount of the added NIPAm was added in an amount of 1/50 that of the added NIPAm, and the mixture was dissolved to prepare Mixed Solution 1.

Subsequently, the mixed solution 1 was introduced into a cylindrical mold having various diameters and immersed in liquid nitrogen at a rate of 1.5 cm / min to induce a pore structure in the longitudinal direction of the tube. A cooled mixture having pore structure formed by liquid nitrogen was prepared. The cooled mixture was irradiated with a UV lamp (wavelength: 365 nm) for crosslinking reaction. During this process, the temperature was maintained at minus 20 ° C.

Thereafter, the dried PNIPAm tube was obtained through a lyophilization process.

Silicone was prepared by mixing ecoflex base and curing agent at the same weight ratio. During the mixing process, air bubbles were removed through a vacuum pump, air bubbles were removed, and the dried PNIPAm tubes were put together and kept at -2 ° C for 2 days. At this time, the pores of the PNIPAm are impregnated with silicon. Since the penetration of ecoflex is relatively weak, it is possible to make local penetration only on the surface.

The ecoflex was then stored in an oven at 40 ° C for 2 days, in an oven at 80 ° C for 1 day, and again at 40 ° C in the oven for 1 day to cure the ecoflex.

As a result, silicon was permeated between the pores of the hydrogel to obtain a crosslinked composite structure.

Example 2: Preparation of composite structure 2 (thermal initiator)

First, a monomer, N-isopropylacrylamide (NIPAm), is dissolved in water at a ratio of 20 wt%, and a crosslinking agent such as methylenebisacrylamide (MBA) and ammonium persulfate A thermal initiator was added and dissolved by 1/50 of the added amount of NIPAm to prepare mixed solution 2.

Subsequently, the mixed solution 2 is placed in a cylindrical mold having various diameters. Thereafter, an elongated cylindrical rod of hydrophobic material, which would serve as a pore in the cylindrical mold, was placed and heat was applied to crosslink the hydrogel. Crosslinked and immersed in liquid nitrogen at a rate of 1.5 cm / min to induce pore structure in the longitudinal direction of the tube. The process of allowing silicone to permeate after the lyophilization process was carried out in the same manner as in Example 1.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 illustrate a composite structure according to an embodiment of the present invention, showing a composite structure including a rubber (for example, silicon) and a hydrogel having an LCST.

As shown in FIG. 1, the composite layer of the composite structure of the present invention may be formed into a structure in which hydrophobic silicon and hydrophilic hydrogel are bonded through a cross-linking process after locally penetrating the silicon on the surface of the hydrogel have. Such a structure allows the hydrogel to absorb water when the temperature is low, thereby expanding its volume and blocking pores. On the other hand, when the temperature rises, the volume can be reduced and the pores can be opened while releasing the water, so that the opening and closing of the pores can be controlled depending on the temperature. As a result, evaporation of water stored in the water layer can be controlled by the composite layer. The silicon contained in the composite layer inhibits vaporization of water and the hydrogel is a portion that vaporizes water. In the hydrogel shown in FIG. 1, it can be seen that the lower end of the hydrogel is extended toward the water stored in the water layer. As described above, a part of the hydrogel comes in contact with the water stored in the water layer, so that the water in the water layer can be absorbed by the hydrogel.

2 is a perspective view of a composite structure manufactured according to an embodiment of the present invention and an actual image of a part of the composite structure. The actual structure of the composite structure according to temperature changes can be compared. 2 (a), the hydrogel having the LCST of the composite structure shrinks and the pores are opened at a high temperature of 45 ° C. When formed on an actual water layer, it is possible to induce vaporization of water stored in the water layer by opening the pores as described above. On the other hand, at a low temperature of 25 占 폚, the hydrogel having the LCST swells and the pores are closed. The vaporization of water stored in the water layer can be suppressed when the pores are closed. The composite structure of the present invention, in which the pore opening / closing is controlled according to the temperature, can store water in the water layer for a longer time and maintains the internal temperature by continuously controlling the vaporization as long as it is stored.

Experiments were conducted to confirm the cooling effect of the composite structure of the present invention.

The surface temperature was measured while applying heat to the composite structure manufactured through the embodiment of the present invention with an infrared lamp. At this time, the distance between the infrared lamp and the complex structure was adjusted to 15 cm, and the intensity of the infrared lamp (maximum output of 250 W) was divided into three stages of 50 w, 100 w and 150 w. Under the above conditions, the composite structure was heated for 5 minutes, and the steady state surface temperature was measured according to each lamp intensity. Table 1 below summarizes the experimental results to show the cooling effect of the composite structure of the present invention.

Counting lamps 50 Watt 100 Watt 150 Watt silicon 40 ℃ 45 ° C 50 ℃ Hydrogel - Silicone 35 ℃ 35 ℃ 35 ℃

It was found that the surface temperature increases with increasing ramp strength in the case of three layers consisting only of silicon without thermosensitive hydrogel. On the other hand, when the hydrogel was included, it was confirmed that the temperature did not increase at 35 ° C. It was confirmed that the hydrogel of the composite structure was shrunk as the temperature was increased by the lamp, and thus, the pores were opened to vaporize the water and the temperature did not increase.

On the other hand, when the hydrogel having no temperature sensitive property, that is, the LCST is not applied to the outer wall of the building, the cooling effect is insignificant.

In addition, when only the thermosensitive hydrogel having no LCST is applied to the outer wall of the building without the hydrophobic substance, unlike the non-temperature sensitive hydrogel, the cooling effect is shown while releasing water according to the temperature, So that the time for carrying water is very short.

When the nanoclay was applied to a thermosensitive hydrogel having a LCST, the vaporization could be suppressed when the temperature was low, but the volume of the hydrogel having an LCST decreased sharply when the temperature was elevated There was a crack in the part where the nanoclay was placed. It was not possible to confirm the effect of vaporization continuously and the suppression of vaporization in the gap. Therefore, if the temperature is increased or decreased repeatedly, the characteristics of the nano-clay are lost and only the characteristic of the hydrogel having the LCST remains, and the vaporization of water continues to occur even at low temperatures. Once the cracked nano-clay layer can not be recovered again, there is a big disadvantage that it can be used only once.

The composite structure of the present invention includes silicon which acts as an outer wall layer for preventing water from evaporating from the outside of the body in the outer skin tissue of the human body and pores of a hydrogel having an LCST serving as a sweat gland for controlling body temperature, But also to an outer wall of a building, a facility or an apparatus of a factory requiring cooling according to an external temperature, and the like. The complex structure of the present invention can be adjusted to a specific temperature range from 25 ° C to 45 ° C by allowing the hydrogel monomer material to be added during the manufacturing process so that aggressive vaporization can occur. When the temperature is below the set temperature, the vaporization of the stored water is suppressed to the maximum. When the temperature exceeds this range, vigorous vaporization occurs and an active cooling effect is produced. In addition, hydrogels and silicon are both soft materials and can be applied to curved or uneven surfaces.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (9)

A water layer disposed in contact with the exterior wall of the building or a surface of a device requiring cooling and including an interior space in which water can be stored; And
A hydrogel having an LCST and a composite layer comprising a hydrophobic substance,
The hydrogel having the LCST includes a pore structure,
Wherein the pore structure controls the vaporization of water in the water layer by opening and closing the pores by shrinkage or expansion of the hydrogel according to temperature.
Complex structure.
The method according to claim 1,
The hydrogel having the LCST may be selected from the group consisting of poly N-isopropylacrylamide, acrylic acid, acrylamide, 2-hydroxyethyl methacrylate, Polyvinyl alcohol, polymethyl methacrylate, vinyl pyrrolidinone, vinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylonitrile, Such as PAN-methyl sulfonate, polysulfone, polycarbonate, poly ester, poly ethylene glycol, polypropylene glycol, poly A polyvinyl alcohol, a cellulose compound, and a mixture thereof.
Complex structure.
The method according to claim 1,
The hydrophobic material may be selected from the group consisting of silicone, butadiene, chloroprene, isobutane, isopentane, isoprene, polyacrylate, styrene-butadiene, ), Acrylonitrile-butadiene, chlorosulphonated polyethylene, ethylene-propylene, ethylene-propylene-diene, fluorocarbon ), Epichlorohydrin, polydimethylsiloxane, urethane, and mixtures thereof. [2] The method according to claim 1,
Complex structure.
The method according to claim 1,
Wherein the thickness of the composite layer is less than or equal to 2 m.
Complex structure.
delete delete delete delete delete

Images