KR102353348B1 - Cement composition having the effect of reducing radient heat using natural meta-nano silk - Google Patents

Abstract

A cement composition having a radiant heat reduction effect of the present invention comprises a silk fibroin powder added thereto, thereby achieving a better heat shielding effect than that of the conventional heat shielding concrete composition. In addition, since a raw material of the silk fibroin powder is easily acquired by simply processing silk balls, which are by-products of silk fiber production, environmental-friendly and economical advantages can be provided at the same time. Due to the properties, the cement composition can be used for mass casting of buildings and manufacturing of large structures, and can be widely used for repair and reinforcement of sections or cracks, post-treatment of building exteriors or roofs, etc.

Description

Cement composition having the effect of reducing radient heat using natural meta-nano silk

The present invention relates to a cement composition having a radiant heat reduction effect containing natural meta nano silk, and more particularly, by containing fine silk fibroin powder having a natural meta structure, a much superior radiant heat reduction effect compared to conventional heat shielding cements or coating methods It relates to a cement composition having a radiant heat reduction effect that is easy to construct while having a low cost of materials or repair and reinforcement.

It is the roof or roof surface temperature that raises the inside temperature of a building in summer rather than the outside temperature. The average solar energy in summer in Korea reaches 5,900 ㎉/㎡, and the roof or roof surface of the building accepts it as it is, causing a problem of cooling load due to an increase in indoor temperature.

However, most of the buildings in our country are only waterproofing construction to prevent water leakage on the roof or roof, and this waterproofing layer has only a waterproof function, and there is a structural problem that the heat shielding problem cannot be solved because there is little heat shielding or thermal insulation effect.

In Korea, the urban concentration phenomenon has deepened due to rapid industrialization since the 1970s. Due to this, the area of green areas has greatly decreased and the population density has increased due to the quantitative expansion of the city. The so-called heat island effect, which is higher than the local area, has emerged as a major social and environmental problem.

The heat island phenomenon is a climatic characteristic that occurs as urbanization and high land use progress. Due to the effects of artificial heat, air pollution, buildings, and paved roads in the city, hot air in the city center is covered with an island shape compared to the surrounding suburbs. means the state of being.

For this reason, the city gives great inconvenience to people every summer due to the radiant heat emitted by a lot of concrete or asphalt, and the heat island phenomenon caused by various pollutants, and it is causing various social side effects. Urban engineers are conducting various studies using wind, green areas, water, reflection and suppression of artificial exhaust heat as an alternative to alleviate the heat island phenomenon, but the effect is insignificant so far.

Recently, in order to solve problems such as the heat island phenomenon as described above, a method of coating a paint containing a heat-shielding component on the surface of a building or block has been proposed. Specifically, if you look for technologies related to conventional heat-shielding paints, there are Republic of Korea Patent No. 10-1169183 or Korean Patent No. 10-1886687, etc., which mostly contain metal components such as metallic inorganic pigments or aluminum silicate, which is the main cause of the temperature rise. It prevents the rise of surface temperature by securing high reflectivity to light in the near-infrared region of the sunlight, and blocks or alleviates the accumulation of heat fundamentally by interfering with heat conduction to an object by including porous particles.

However, the above paints exhibit waterproofing and solar heat shielding effects in the concrete structure, and have good initial adhesion, but exhibit great differences from concrete in deformation characteristics such as coefficient of thermal expansion, drying, and shrinkage, and thus fall off from the interface of concrete in the long term. This occurs, and thus adhesive strength is lowered, and the surface has poor contamination resistance, which makes it difficult to secure long-term durability. This phenomenon shortens the lifespan of the structure, and also has a problem in that the maintenance cost is much higher than the construction cost because continuous maintenance and repair is required.

Republic of Korea Patent Registration No. 10-1169183 (July 20, 2012) Republic of Korea Patent Registration No. 10-1886687 (August 02, 2018)

The present invention has been devised to solve the above problems, and in detail, by containing fine silk fibroin powder having a natural meta-structure, it is possible to collect or strongly reflect sunlight at an ultra-high density, so that it can be applied to conventional heat-shielding cement or coating methods. It relates to a cement composition having a radiant heat reduction effect, including natural meta nano silk, which has a much superior radiation heat reduction effect compared to that, is easy to construct, and is inexpensive in materials or repair and reinforcement costs.

The present invention relates to a cement composition having a radiant heat reduction effect comprising natural meta nano silk.

One aspect of the present invention is a cement composition containing cement and fibroin powder, wherein the fibroin powder is a fine powder with an average particle diameter of 100 μm or less obtained by grinding a refined cocoon with a dry mechanical grinding means. It relates to a cement composition.

In the present invention, the cement composition contains 0.1 to 5 parts by weight of fibroin powder relative to 100 parts by weight of cement, and the fibroin powder is any one selected from an aqueous alkali solution, an acidic aqueous solution, an aqueous enzyme solution, and an aqueous amine solution set at 50 to 200 ° C. It is characterized in that it is made of fibroin fibers refined by contacting a cocoon with a plurality of scouring solutions for 0.1 to 5 hours.

In this case, the fibroin powder is

a) a refining step of refining the cocoon by contacting the refining solution to the cocoon;

b) a first pulverizing step of pulverizing the refined cocoon into short fibers using a dry mechanical pulverizing means; and

c) a second grinding step of pulverizing the short fibers into a fine powder having an average particle size of 100 μm or less by pulverizing the short fibers with a dry mechanical grinding means;

Doedoe prepared including, step b) is performed using a powder mixer equipped with an impeller, and step c) is a planetary mill equipped with three types of balls having different diameters. mill) is characterized in that it is carried out using

The cement composition having the effect of reducing radiant heat according to the present invention can achieve a much better heat shielding effect than the conventional heat shielding concrete composition by adding silk fibroin powder to the composition as described above. In addition, since the raw material of the silk fibroin powder can be easily obtained by simple processing of jellied silk, a by-product of silk fiber production, it can have environmental-friendly and economic advantages at the same time.

As the cement composition according to the present invention has the above characteristics, it is not only used for mass casting of buildings and for manufacturing large structures, but also widely used for repairing and reinforcing sections or cracks, and for post-treatment of building exteriors or roofs, etc. It is possible.

1 shows a thermo-hygrostat device and a specimen having a lamp inside used in Examples 1 to 4 and Comparative Example 1. Referring to FIG.

Hereinafter, the cement composition having the effect of reducing radiant heat according to the present invention will be described in more detail. However, the embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

Therefore, the present invention is not limited to the embodiments presented below and may be embodied in other forms, and the embodiments presented below are merely described to clarify the spirit of the present invention, and the present invention is not limited thereto.

At this time, unless there are other definitions in the technical terms and scientific terms used, it has a meaning commonly understood by a person of ordinary skill in the art to which this invention belongs, and in the following description, it may unnecessarily obscure the subject matter of the present invention. A description of possible known functions and configurations will be omitted.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms unless the context specifically dictates otherwise.

The present invention forms a kind of film by coating a composition containing a metal pigment, etc. on the surface of most structures in the conventional construction method for heat shielding and insulation. Aside from the problem of discharging substances and harmful substances, the coefficient of thermal expansion with the application target and deformation characteristics such as drying and shrinkage show a large difference, resulting in long-term drop-off at the interface of the application target, thereby lowering the adhesive strength. In the course of recognizing problems such as a significant decrease in surface contamination resistance and repeated research to solve this problem, when fibroin powder having a natural meta-structure is added to the cement composition, the existing cement or concrete composition having heat-shielding properties The present invention was completed by confirming a much more environmentally friendly and excellent temperature reduction effect compared to the present invention.

Since ancient times, clothes made of white silk give the wearer a much cooler feeling than other fabrics. In the past, this characteristic of silk was known to reflect light more simply because it had a white color. It turns out that it could be clothes like a mirror or a black hole.

In general, metamaterials or metastructures are needed to collect and resonate light with high efficiency and density. These metastructures or metamaterials are designed according to physical theories and are manufactured finely and precisely with cutting-edge technology, so they do not exist in nature. known to have physical properties.

However, there is an exceptional case in which light resonance is possible without a precisely fabricated regular structure, which is called the Anderson localization phenomenon. The Anderson agglomeration phenomenon was discovered by Phillip Anderson in 1958, and is a phenomenon in which the conduction of a wave disappears due to an irregular structure and is trapped inside.

For the Anderson light aggregation phenomenon to occur, interference must occur between the scattered light waves. Irregularly dense nanostructures must scatter light, and the scattered light waves must undergo constructive or destructive interference. In case of strong constructive interference by chance, light is condensed to form high energy inside the nanostructure.

The silk fibers obtained from the cocoon have a structure capable of generating the Anderson photocoagulation phenomenon well. The silk fibers with a diameter of 10 to 20 μm are composed of thousands of other nanofibers with a diameter of about 100 nm inside.

Each of the nanofibers inside the silk fiber acts as an individual scatterer, and the Anderson light aggregation phenomenon arises from light scattering due to the nanofiber inside. In particular, the nanofibers aligned side by side align the scattering direction of light so that the scattered waves have a good coherence and interfere with each other with high probability. Therefore, a very small fraction of visible light wavelengths are condensed inside the silk, but most wavelengths of light are strongly reflected off the silk surface.

Therefore, when the strong visible light reflection property by Anderson's photocoagulation phenomenon is combined with the high infrared emission property due to the special protein structure of silk, it can radiate more heat than it absorbs and create a cool effect without other energy. point was confirmed.

In addition, in the case of the silk, many by-products are inevitably generated in the process of producing clothing, etc., and since it is possible to obtain silk fibers that can be put into the composition by simply processing the by-products, especially the cleavage fibers, compared to other heat-blocking materials. The present invention was completed by confirming that the generation of volatile organic compounds (VOCs) can be significantly reduced due to the much more economical and eco-friendly properties of silk.

The cement composition having the effect of reducing radiant heat according to the present invention basically contains cement and fibroin powder, wherein the fibroin powder is a fine powder having an average particle diameter of 100 μm or less, which is pulverized from a refined cocoon by a dry mechanical grinding means. .

In the present invention, the cement is not limited to the type as long as it is included in mortar or concrete in the art, and preferably general Portland cement, crude steel portland cement, early steel Portland cement, medium heat Portland cement, sulfate resistant Portland cement, or white Portland cement. Any one or a mixture of cement and super-velocity cement may be used, but is not limited thereto.

The cement may be used not only in powder form but also in clinker form. However, in the case of using cement clinker, it is preferable to use what has been calcined and pulverized as a pretreatment, and in this case, the cement preferably has a specific surface area of 2,000 cm ² /g to 8,000 cm ² /g.

In the present invention, the fibroin powder is obtained by removing sericin from a common cocoon and pulverizing the remaining fibroin, wherein the fibroin is obtained through a physical grinding method rather than a chemical method.

The reason why silk fibers show Anderson's light aggregation as described above is that because silk fibers are basically made by braiding tens to thousands of nano-diameter filaments, a number of nanofibers are positioned side by side, and each nanofiber is This is because the scattered waves have a good coherence and interfere with each other with high probability by aligning the scattering direction of

Therefore, as the fibroin powder, unlike the fibroin fiber added to a general cement composition, a powder obtained by pulverizing the fibroin fiber by a physical grinding method should be used. In particular, fibroin fibers used in general cement compositions, for example, fibroin fibers disclosed in Korean Patent Registration No. 10-2179840, etc. are spun by a method such as electrospinning after completely dissolving the fibroin component in a solvent to make a spinning solution, In the fibroin fibers prepared by this method, the Anderson light aggregation phenomenon does not appear because the above-described nanofiber scattering body structure is completely destroyed.

In the present invention, the fibroin powder is basically prepared by pulverizing the fibroin fibers obtained after refining the cocoon, specifically,

a) a refining step of refining the cocoon by contacting the refining solution to the cocoon;

b) a first pulverizing step of pulverizing the refined cocoon into short fibers using a dry mechanical pulverizing means; and

c) a second grinding step of pulverizing the short fibers into a fine powder having an average particle size of 100 μm or less by pulverizing the short fibers with a dry mechanical grinding means;

It can be prepared including

Step a) is a refining step of removing unnecessary component sericin by contacting the cocoon with the refining solution.

In general, the liquid silk biosynthesized from the silk glands of silkworms composed of 18 amino acids has a high crystallinity fiber arrangement by the silt of the silkworm, and has an elongation of 18 to 24% at 3.8 to 4.2 g/d. Silk formed from two components of about 75% by weight of fibroin and about 25% by weight of sericin is produced.

Sericin is a representative water-soluble globular protein that forms a gel-like gum and wraps around fibroin, a fiber body. It acts as a bonding agent between the fibroin fibers and the cocoon and the base, and functions as a lubricant when forming fibroin fibers.

In the present invention, the cocoon is not limited to the type as long as it is commonly used for textile or bio use in the art. In the case of Korea, 17 kinds of silkworm incentives are designated for the purpose of cocoon production and educational silkworm production, and in the present invention, all of them can be used. -1, N28, Chuhwa, N74 (fusiform cocoon), Chinese silkworm, European Bagdad (1 Hwaseong), Romogua (1 Hwaseong), tropical SA6 (multiple cocoon), Korean three-sided red chrysanthemum (4 Myeonjam), Seon No. 3 (three-sided sleep), etc. may be included, and two or more of these may be mixed and used.

However, since the weight and thickness of the silk layer, the density of the silk layer, the tensile strength, etc. are different depending on the type of cocoon, it can be selectively applied depending on the conditions of the grinding process described later or the average particle size of the silk powder produced. For example, it is recommended to increase the rotation speed of the impeller or ball in the crushing stage or to take a longer crushing time for varieties such as Seon 3 or three-sided red ginseng that have high cutting strength. The particle size of silk particles can be determined by lowering the rotation speed or adjusting the size of the ball.

In the present invention, the electrostatic agent may be used as long as it is a refining agent commonly used when removing sericin from a cocoon. Aqueous alkali aqueous solution which is, for example, aqueous solutions, such as sodium hydroxide, sodium carbonate, calcium carbonate, sodium silicate, sodium phosphate, sodium bicarbonate, borax, ammonia; acidic aqueous solutions, such as lactic acid, tartaric acid, citric acid, oxalic acid, malonic acid, succinic acid, acetic acid, chloroacetic acid, dichloroacetic acid and trichloroacetic acid; Enzyme aqueous solution which is an aqueous solution, such as trypsin (Trypsin) and papain (Papain); and an amine aqueous solution containing amines such as methyl amine and ethyl amine, in addition to tallow oil, olive oil, coconut oil, caster oil, arachis oil Arachis oil, Cotton seed oil, Chrysalis oil, Sodium Laurate, Sodium Myristate, Sodium Stearate, Sodium Arachidate (Sodium Arachidate), Sodium Oleate (Sodium Oleate), Sodium Ricinoleate (Sodium Ricinoleate), etc. surfactants dissolved in water may be used.

The bath ratio of silk to the scouring bath containing the scouring agent (Bath ratio, w/v, g/mL) is preferably 1:5 to 100 by volume of silk:scouring bath. When the bath ratio is less than the above range, the scouring solution is not sufficiently immersed in the silk, so that the removal of sericin is not performed efficiently.

Step a) may be performed by contacting the refining solution set at 50 to 200° C. for 0.1 to 5 hours. Only fibroin can be effectively obtained without damage through the refining process, and when the process is performed below the above temperature or time range, sericin is not sufficiently removed. This can lead to destruction of the nanostructure.

In step a), only the fibroin component may be collected through physical stirring if necessary. At this time, as a physical stirring means, for example, there is an ultrasonic wave, a stirrer, a stirring rod, etc., and the stirring conditions using the same are not limited within the range that does not impair the object of the present invention.

In addition, after using an acid or alkali aqueous solution as the refining solution, a neutralizing step may be further added. Sericin in the hydrolyzed solution can be precipitated and precipitated as fine particles through neutralization, and only complete fibroin fibers can be obtained through filtration, desalting, drying processes, etc.

In the present invention, step b) is a first grinding step, and is a process of grinding the refined cocoon into short fibers by a dry mechanical grinding means. In this case, the 'short fiber' is formed by cutting fibroin having the shape of a filament several times, and the length is not limited, but it means having a length of about 5 cm or less.

The pulverizer usable in step b) is not limited to the type as long as it can cut long-fiber fibroin into short fibers through a dry process, for example, an air jet mill, a rotary mill, There are hammer mills, extruder mills, hydraulic crushers, powder mixers, and the like. Among them, an impeller is provided inside so that the fibroin fibers are uniformly mixed while simultaneously grinding and surface modification. It is preferable to use a powder mixer that can achieve

In the present invention, the shape and configuration of the powder mixer is not limited in the present invention, but basically, as in Korean Patent Registration No. 10-1276352, a main body to be pulverized and a blade rotatably mounted inside the main body and bent in cross section It may include an impeller having and a motor rotating the impeller.

At this time, an opening is formed on the upper side of the main body, and a lid for opening and closing the opening is mounted at one end of the opening to prevent short fibers from escaping out of the main body when the fibroin is pulverized, and the impeller is a bottom surface of the inner surface of the main body. It is preferable to be rotatably mounted to the.

The impeller may include a boss coupled to the rotation shaft and a plurality of blades formed on an outer surface of the boss, and one or two or more of the above impellers may be provided as necessary.

In addition, it is preferable to accommodate the ceramic beads together in the body in order to facilitate the grinding of the fibroin fibers separately from the impeller and to shorten the diameter (fineness) or length of the pulverized fibroin fibers. The ceramic beads cause friction with the fibroin fibers while being moved by the impeller, resulting in a shorter length or fineness of the fibers.

The boss is rotatably mounted on the bottom surface of the main body, and can move up and down inside the main body in the axial direction at the same time as the rotation if necessary. The boss may be formed with an insertion hole into which a shaft for rotation is inserted in the center, and is moved by receiving rotational force by the above-described motor.

The wings are disposed on the outer circumferential surface of the boss radially to each other in the direction of the inner circumferential surface of the main body, and may be attached to be inclined at a predetermined angle. In this case, it is preferable that the blade has a long rectangular shape in one direction and a blade portion formed in the shape of a blade for cutting the fibroin fiber is provided at the end.

The motor rotates the rotation shaft to transmit rotation to the impeller, and it is preferable to maintain a high number of rotations in order to shorten the fibroin fiber formation and grinding time. Specifically, it is preferable that the motor abduct the shaft so that the revolving speed of the impeller is 10 to 50 rpm, and the grinding speed of the cocoon is 1,000 to 15,000 rpm.

In addition, the powder mixer may further include a rotating means for rotating the main body as described in Korean Patent Registration No. 10-0935688. The rotating means increases the number of contact between the impeller and the fibroin fiber while moving up, down, left and right in addition to the movement of the fibroin fiber by the impeller by revolving the body itself, and at the same time the cut short fiber type fibroin fiber is laminated on the bottom of the body It can prevent further cuts being made.

In step b), as described above, the impeller is rotated by driving the motor to induce cutting of the fibroin fiber, but the revolving speed of the impeller is 10 to 50 rpm, and the grinding speed of the cocoon is preferably maintained at 1,000 to 15,000 rpm. do. When it is driven below the above range, the second crushing, which will be described later, is not properly performed because the fiber length becomes longer. In addition, it is preferable that step b) proceeds for 1 to 5 minutes.

Next, as in step c), a second grinding step of pulverizing the short fibroin fibers into a fine powder having an average particle size of 100 μm or less by pulverizing the fibroin short fibers with a dry mechanical pulverizing means may be performed.

In the present invention, step c) is a process for producing a fine powder form by pulverizing the fibroin fibers in the form of short fibers with a mechanical grinding means. In this case, the 'fine powder' means that the fibroin in the form of short fibers is completely abraded to form particles having a very small diameter, and the particle size is not limited, but it means having a diameter of about 100 μm or less.

The pulverizer usable in step c) is not limited to the type as long as it can cut long-fiber fibroin into short fibers through a dry process similar to step b), for example, an air jet mill, There are rotary mills, hammer mills, extruder mills, hydraulic crushers, powder mixers, planetary mills, etc. It is preferable to use a planetary mill capable of inducing grinding and abrasion of the fibroin powder.

The planetary mill is an equipment manufactured to simultaneously revolve and rotate at high speed, has one or more bowls, and is provided so that the bowls are fixed on a circular rotating plate. At the same time as the rotating plate rotates, the bowl is each independently configured to rotate in the opposite direction to the rotating direction of the rotating plate. It uses the principle of dispersion.

In the present invention, the ball inserted into the bowl is a spherical object having an overall round shape as in the term, meaning excluding angular shapes such as plate shape, and does not mean a perfect spherical shape, but an oval or its It may also include a spherical shape with some dents.

Preferably, the ball is basically formed of ceramic particles. Examples of such ceramic particles include alumina, aluminum nitride, silica, titanium oxide, zirconia, and the like, and these may be used alone or in combination of two or more.

In addition, the ball is not limited in diameter, but preferably has a diameter of 1 to 50 mm, and all balls having the same diameter may be applied, but three types of balls having different diameters are mixed and the It is preferably located inside the bowl. In this case, it is preferable that the ball is provided with a mixture of a large-diameter ball having a diameter of 10 to 30 mm, a medium-diameter ball having a diameter of 5 to 20 mm, and a small-diameter ball having a diameter of 1 to 10 mm.

As described above, taking various sizes of the balls generally increases the force applied to the balls as the number of rotations increases. This is because the fibers can be cut easily.

However, if the diameter of the ball is large, since the size of the bowl must be relatively large, the energy for applying the rotation may be excessively consumed. In particular, when the critical rotation speed is exceeded, the impact energy and crushing speed increase as the ball rotates along the bowl and the rotation speed of the ball increases to the same as the rotation speed of the bowl. Since it cannot be done, a ball with a small diameter is put together to increase the number of contact between the fibroin fiber and the ball.

The balls are preferably 1 to 5 large-diameter balls, 10 to 50 medium-diameter balls, and 100 to 1,000 small-diameter balls per bowl. If it is out of the above range, the proper ratio between the fibroin fibers and the balls is exceeded, so that the particle size of the powder is different or the grinding effect is not performed properly, and the grinding effect may be deteriorated.

In addition, in step c), it is preferable to pulverize the pulverized fibroin fibers for 0.1 to 2 hours at a speed of 100 to 500 rpm to adjust the particle size of the pulverized fibroin fibers to 100 μm or less. If it is out of the above range, the particle size may exceed 100 μm or the particle size may not be uniform, and the yield of the powder may be reduced. In addition, during the grinding process as described above, in order to prevent excessive oxidation of the fibroin powder, it is preferable to maintain the inside of the bowl in an inert gas atmosphere during the process.

Here, step c) is characterized in that the cocoon and the ball are sequentially put into a bowl and pulverized. That is, after putting the short fibroin fibers into the bowl first and placing them on the bottom surface, the balls having the three sizes of diameters are first uniformly mixed as described above, and then put into the bowl to make the balls on the short fibroin fibers. to place it. When the ball is placed on the short fibroin fibers as described above, the diameter of the fibroin powder becomes uniform to 100 μm or less, and a yield of 90% or more can be achieved.

To explain this in more detail, it is important to apply a mechanical shear force to the short fibroin fibers when performing planetary mill grinding as described above. In order to compress the fibers as much as possible, it is preferable to put the short fibroin fibers in the bowl as described above and then put the balls on them. Due to the difference, the short fibroin fibers first move toward the top surface of the bowl and the ball is located below it, so the mechanical shear force is hardly transmitted to the short fibroin fibers, and the powder diameter becomes irregular and the yield decreases.

The fibroin powder produced through the above process may be further subjected to post-treatment if necessary. In particular, since ceramic powder may be generated together during milling by a ball as described above, it is preferable to obtain only pure fibroin powder by removing large-diameter particles or heavy ball powder through a method such as centrifugation.

In the present invention, the cement composition preferably contains 0.1 to 5 parts by weight of fibroin powder, more preferably 0.5 to 1 parts by weight, based on 100 parts by weight of cement. When the fibroin powder is added below the above range, the Anderson light aggregation phenomenon is not properly expressed, and when added above the above range, mechanical properties such as tensile strength and breaking strength of the composition may be reduced.

In the present invention, the cement composition may further include water, aggregates, and other additives based on the cement and fibroin powder. In this case, the aggregate means sand or crushed stone, and in particular crushed stone may act as a criterion for classifying mortar or concrete according to the addition.

Although the type of water is not limited in the present invention, it is preferable to use clean purified water without impurities. In addition, water and binder (powder (W/B) such as cement and slag) are numerical values that determine the strength and durability of concrete such as design standard strength and blending strength, and W/B is 15 to 60% by weight. This is preferable under the condition that drying shrinkage of cement, material separation, etc. do not occur.

The crushed stone can be divided into coarse aggregate and fine aggregate according to the thickness of the particles. In detail, it can be defined as mortar when only fine aggregates are included, and concrete when both fine aggregates and coarse aggregates are included.

The coarse aggregate is generally also called gravel (gravels), as long as it is generally used in the art, it is not limited to the type. The coarse aggregate is preferably crushed aggregate or natural aggregate, preferably one that satisfies KS F 2502 or KS F 2527.

The fine aggregate is generally referred to as sand, and both fine aggregate and coarse aggregate can be used. The fine aggregate is preferably a material that almost completely passes through the No. 4 sieve (ASTM C125, 4.75 mm), and it is preferable to use silica sand or the like. The coarse aggregate is a material mainly remaining in sieve No. 4 (ASTM C125, 4.75 mm), for example, silica sand, quartz, marble, granite, limestone, calcite, feldspar, alluvial sand, other durable aggregates such as sand, or their The mixture is good. In addition, in the present invention, in order to determine the fluidity of concrete, it is preferable that the fine aggregate ratio (S/a) satisfies 35 to 55 volume %, which is the volume ratio of sand (S) to the total aggregate (sand + gravel, a) volume. can be calculated

The additive is added to achieve effects such as strength improvement or miscibility improvement depending on the application purpose of the cement, and the type is not limited. , accelerators, retarders, strength improving agents, curing retardants, wetting agents, water-soluble polymers, rheology modifiers, water repellents, permeability reducing agents, pumping aids, sterilizing agents and alkali reaction reducing agents, and the like.

The blast furnace slag is finely pulverized water slag, a by-product of the pig iron manufacturing process, and serves to increase the long-term strength of cement and increase watertightness and seawater resistance. The blast furnace slag has a fineness of 2,000 to 15,000 cm ² /g, preferably 4,000 to 8,000 cm ² /g, so that the strength of the concrete composition is not reduced while maintaining the fluidity of the concrete composition. In addition, the blast furnace slag preferably contains 2 to 6% by weight of sulfuric anhydride (SO ₃ ) based on 100% by weight of the total, and preferably 2 to 3% by weight is added. The anhydrous sulfuric acid is added when pulverizing blast furnace slag, and serves as a secondary irritant.

The fly ash serves to enhance the long-term strength of concrete by the pozzolan reaction and to strengthen the watertightness, durability, and chemical resistance of the concrete structure. , Preferably, it is preferable to use a thing falling within the range of 2.1 to 2.2, the fineness is 3,500 to 4,500 cm / g, and it is preferable to use a thing with a loss on ignition of less than 5%.

The cement composition having the effect of reducing radiant heat according to the present invention can achieve a much better heat shielding effect than the conventional heat shielding concrete composition by adding silk fibroin powder to the composition as described above. In addition, since the raw material of the silk fibroin powder can be easily obtained by simple processing of jellied silk, a by-product of silk fiber production, it can have both eco-friendly and economical advantages.

As the cement composition according to the present invention has the above characteristics, it is not only used for mass casting of buildings and for manufacturing large structures, but also widely used for repairing and reinforcing sections or cracks, and for post-treatment of building exteriors or roofs, etc. It is possible.

Hereinafter, a method for producing silk fibroin powder according to the present invention will be described in more detail by way of example. However, the following examples are only examples for explaining the present invention in more detail, and the present invention is not limited to the following examples.

The method of measuring the physical properties of the specimens prepared in Examples and Comparative Examples and the resources of the samples used are as follows.

(Specification)

Specifications of cocoons, mixers and balls used in Examples are shown in Table 1 below.

[Table 1]

(lamp irradiation)

A specimen was installed in the constant temperature and humidity device of FIG. 1, and a lamp was irradiated to the specimen to investigate the temperature change. Specifically, as shown in FIG. 1, two 'L'-shaped frames positioned side by side in a parallel direction were provided to be spaced apart from the bottom by a certain distance, and three lamps (220V, 250W) capable of irradiating light in the bottom direction on the top surface. A rectangular parallelepiped frame with a size of 900 mm × 900 mm × 1,600 mm was prepared so as to be spaced 60 cm apart from the 'L' frame. At this time, the rectangular parallelepiped frame blocks the inside and outside of the frame with glass to suppress temperature change due to convection.

And the specimens prepared in Examples 1 to 4 and Comparative Example 1 were placed on the ‘L’-shaped frame. At this time, the specimen was 300 mm × 400 mm × 20 mm in size, and a temperature measuring device (OMEGA SAI-RTD sensor-Class A) was attached to the opposite and opposite surfaces of the lamp.

In the experiment, the temperature outside the frame, the temperature inside, and the temperature of the specimen were measured respectively, then all three lamps were operated and the temperature was measured after 3 hours, and the temperature difference between the temperature inside the frame and the specimen was calculated. In addition, the experiment was repeated 3 times for each specimen.

(Production Example)

To prepare silk fibroin powder, first, sodium stearate was dissolved in a silkworm cocoon at 5 g / ℓ, and it was put into a scouring solution whose temperature was set to 80 ° C, but the liquid ratio was 3: 100 by volume, soaked for 2 hours, washed with water and dried did.

Next, the cocoon in the fibroin state was put into the powder mixer of Table 1, and the idle speed was set to 15 rpm and the grinding speed to 10,000 rpm, and then pulverized for 3 minutes. After grinding, there was a rest period of 1 minute, and then grinding was repeated for 3 minutes, followed by grinding a total of 10 times to obtain short-fiber fibroin.

Next, 3.3 g of the fibroin short fibers and the milling balls of Table 1 were put into the planetary mill, but the short fibroin fibers were first put into the bowl, and then the milling balls were added. Then, the revolution speed was set to 300 rpm and the grinding speed was set to 690 rpm, and the powder was pulverized for 90 minutes to obtain a fibroin powder.

(Examples 1 to 3 and Comparative Example 1)

To make a specimen, a composition was prepared by mixing non-shrinkable mortar (ARDEX A45 ultra-high-strength high-strength non-shrinkable mortar), water and fibroin powder in the ratio shown in Table 2 below, molded with a vibrating press and cured to prepare a specimen, fibroin Since it has the property of absorbing water, the amount of fibroin added and the amount of water added were increased together. The physical properties of the prepared specimens were measured and shown in Table 3 below.

[Table 2]

[Table 3]

As shown in Table 3, the cement composition prepared according to the present invention exhibits a maximum temperature of 2.76° C. lower than that of the specimen without the addition of fibroin powder (Comparative Example 1), so that the fibroin powder effectively inhibits the temperature rise of the specimen. can check that However, considering that Example 2 has a slightly greater effect of inhibiting the temperature rise than Example 3, which has a larger fibroin powder content, it is most preferable when the fibroin powder is added in an amount of 0.5 to 1 part by weight relative to 100 parts by weight of cement. can be checked

The above description is merely illustrative of the present invention, and various modifications will be possible without departing from the technical spirit of the present invention by those of ordinary skill in the art to which the present invention pertains, The examples do not limit the present invention. The scope of the present invention should be interpreted by the following claims, and all technologies within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (6)

A cement composition containing cement and fibroin powder, wherein the fibroin powder is a fine powder with an average particle diameter of 100 μm or less, obtained by pulverizing a refined cocoon by a dry mechanical grinding means,
The cement composition contains 0.1 to 1 part by weight of fibroin powder based on 100 parts by weight of cement,
The fibroin powder,
a) a refining step of refining the cocoon by contacting the cocoon with any one or a plurality of refining solutions selected from an aqueous alkali solution, an acid solution, an aqueous enzyme solution and an aqueous amine solution set at 50 to 200° C. for 0.1 to 5 hours;
b) a first pulverizing step of pulverizing the refined cocoon into short fibers using a dry mechanical pulverizing means; and
c) a second grinding step of pulverizing the short fibers into fine powders having an average particle diameter of 100 μm or less by pulverizing the short fibers with a planetary mill equipped with three types of balls having different diameters;
Including, wherein the balls are 1 to 5 large-diameter balls having a diameter of 10 to 30 mm, 10 to 50 medium-diameter balls having a diameter of 5 to 20 mm, and 100 to 1,000 small-diameter balls having a diameter of 1 to 10 mm A cement composition having a radiant heat reduction effect comprising natural meta nano silk, characterized in that it is prepared by including
delete delete delete The method of claim 1,
Step b) is a cement composition having a radiant heat reduction effect comprising natural meta nano silk, characterized in that it is performed using a powder mixer equipped with an impeller. delete

Images