KR102747453B1 - Manufacturing method of feed storage tank - Google Patents

Abstract

The present invention relates to a method for manufacturing a feed storage tank, and more specifically, to a method for manufacturing a feed storage tank, which exhibits excellent mechanical strength, so that it can be used for a long period of time without changing its shape, is easy to change its design, and is cost-effective, so that mass production is possible. To this end, the manufacturing method comprises the steps of: preparing a mold that exhibits a tank shape when joined; applying a gel coat to an inner surface of the mold; curing the gel coat to form a first layer; attaching glass fibers to the first layer and applying a liquid composition containing an unsaturated polyester resin; curing the liquid composition to form a glass fiber layer; applying a gel coat to the glass fiber layer; curing the gel coat to form a second layer; and removing the mold from the mold to obtain a feed storage tank.

Description

MANUFACTURING METHOD OF FEED STORAGE TANK

The present invention relates to a method for manufacturing a feed storage tank, and more specifically, to a method for manufacturing a feed storage tank which exhibits excellent mechanical strength, can be used for a long period of time without changing its shape, is easy to change in design, and is cost-effective, enabling mass production.

In general, feed storage tanks are installed in open areas such as livestock farms where livestock is raised on a large scale, and are used as storage places for feed. The feed storage tanks store feed that can be administered to livestock for a certain period of time, and an appropriate amount is withdrawn and supplied manually as needed.

Since these feed storage tanks are fixed in a state where they are directly exposed to the outdoors, if various nutrients contained in the stored feed are destroyed by direct sunlight, etc., nutritional efficiency will decrease, and since the feed storage tanks are made of non-combustible materials, there is a risk of damage if a fire breaks out as it cannot be extinguished.

If the feed in the feed storage tank is severely dried or contaminated with a large amount of moisture, not only will the freshness be reduced and the nutrients destroyed, but the storage period of the feed will be shortened, which will increase transportation costs, and there will also be a problem in that the feed cannot fall naturally during the discharge process, which will delay the discharge process.

Accordingly, there is a method of covering the feed storage tank with a protective cover as a means of preventing the feed storage tank from being directly exposed to the external environment, but since the structure and size of the protective cover are simple, not only is the scope of application limited when the volume of the feed storage tank changes, but there is also the problem of it being easily separated by wind, etc.

Conventional feed storage tanks are made of a single sheet of iron, etc., and feed storage tanks constructed of a single layer using such materials can easily cause feed to spoil and become tangled due to radiant heat and feed heat generation when stored for a long time. This phenomenon is particularly severe in the summer when the amount of radiation and feed heat generation increase. When feed spoils, nutrients are destroyed and freshness decreases, making it unusable as feed. In addition, when feed tangle occurs, it acts as a factor that interferes with smooth supply in automatic supply lines, causing various difficulties in the supply of feed to livestock farms.

In livestock farms, feed is an important element for providing necessary nutrients when raising livestock, and when raising them in groups, a feed storage tank is essential for supplying feed. Generally, feed stored in a feed storage tank is consumed over several hours, so it is necessary to effectively separate the inside and outside of the tank to prevent deterioration of the feed and maintain freshness.

Republic of Korea Patent Publication No. 10-1436860

The present invention is intended to solve the above problems, and to provide a method for manufacturing a feed storage tank that exhibits excellent mechanical strength and sealing power to effectively separate the inside and outside of the tank, thereby preventing deterioration of feed and maintaining freshness.

The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The above object can be achieved by a method for manufacturing a feed storage tank, comprising: a step of preparing a mold having a tank shape when combined; a step of applying a gel coat to an inner surface of the mold; a step of curing the gel coat to form a first layer; a step of attaching glass fibers to the first layer and applying a liquid composition containing an unsaturated polyester resin; a step of curing the liquid composition to form a glass fiber layer; a step of applying a gel coat to the glass fiber layer; a step of curing the gel coat to form a second layer; and a step of demolding from the mold to obtain a feed storage tank.

Specifically, the gelcoat may be characterized by including an unsaturated polyester resin and a reactive solvent.

Specifically, the step of attaching glass fibers to the first layer and applying a liquid composition containing an unsaturated polyester resin may be characterized in that it is repeated 2 to 5 times.

Specifically, the step of applying a gel coat to the inner surface of the mold may be characterized by performing a masking process on a part of the inner surface of the mold and applying the gel coat, and the step of attaching glass fibers to the first layer and applying a liquid composition containing an unsaturated polyester resin may be characterized by performing a masking process after attaching the glass fibers and applying a liquid composition containing an unsaturated polyester resin, thereby forming a transparent window in the feed storage tank.

Specifically, it may be characterized by further including, after the step of obtaining a feed storage tank by demolding from the mold, a step of reapplying a gel coat to a portion of the obtained feed storage tank that requires maintenance and curing the same.

According to the present invention, it is possible to manufacture a feed storage tank that exhibits excellent mechanical strength and can be used for a long period of time without changing its shape.

In addition, the feed storage tank manufactured by the method according to the present invention has the inside and outside of the tank clearly separated and blocked, so that the odor of the feed, etc. does not leak out to the outside, and even if the external temperature and environment change rapidly, the internal feed product can be prevented from spoiling and the freshness can be maintained.

In addition, it has the advantage of being able to easily check the status of feed stored in the feed storage tank in real time, being easy to change the design, and being able to mass-produce with significantly reduced production costs.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Figure 1 is a flow chart showing a method for manufacturing a feed storage tank according to one embodiment of the present invention.
Figures 2 (a) to (d) are images showing a method for manufacturing a feed storage tank according to one embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to examples and drawings of the present invention. It will be apparent to those skilled in the art that these examples are merely presented as examples to more specifically explain the present invention, and that the scope of the present invention is not limited by these examples.

Additionally, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in case of conflict, the description in this specification, including definitions, shall prevail.

In order to clearly explain the invention proposed in the drawings, parts that are not related to the description have been omitted, and similar parts have been given similar drawing reference numerals throughout the specification. In addition, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components can be further included, unless otherwise specifically stated. In addition, a "part" described in the specification means a single unit or block that performs a specific function.

The identification codes (1st, 2nd, etc.) for each step are used for convenience of explanation and do not describe the order of each step. Each step may be performed in a different order than stated unless the context clearly indicates a specific order. That is, each step may be performed in the same order as stated, may be performed substantially simultaneously, or may be performed in the opposite order.

Hereinafter, implementation examples and embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention may not be limited to these implementation examples and embodiments and drawings.

One aspect of the present invention provides a method for manufacturing a feed storage tank, comprising the steps of: preparing a mold having a tank shape when combined; applying a gel coat to an inner surface of the mold; curing the gel coat to form a first layer; attaching glass fibers to the first layer and applying a liquid composition containing an unsaturated polyester resin; curing the liquid composition to form a glass fiber layer; applying a gel coat to the glass fiber layer; curing the gel coat to form a second layer; and demolding the mold to obtain a feed storage tank.

According to the present invention, a feed storage tank exhibiting excellent mechanical strength and usable for a long period of time without change in shape can be manufactured.

In addition, the feed storage tank manufactured by the method according to the present invention has the inside and outside of the tank clearly separated and blocked, so that the odor of the feed, etc., does not leak out to the outside, and even if the external temperature and environment change rapidly, the internal feed product can be prevented from spoiling and the freshness can be maintained. In addition, it has the advantage that the condition of the feed stored in the feed storage tank can be easily checked in real time, the design can be easily changed, and the production cost is greatly reduced, so that mass production is possible.

Hereinafter, a method for manufacturing a feed storage tank according to the present invention will be described in detail with reference to FIG. 1.

First, prepare a mold that represents the tank shape when combined.

In one embodiment, the mold may be formed of a left mold and a right mold that are symmetrical to each other in the left-right direction and exhibit a tank shape when combined. Since the mold is formed of a left mold and a right mold rather than a conventional mold, the problem of not being able to easily demold can be solved.

Next, a gelcoat is applied to the inner surface of the mold. For example, if the molds are formed into a left mold and a right mold that are symmetrical to each other in the left-right direction and exhibit a tank shape when combined, a gelcoat may be applied to the inner surface after the left mold and the right mold are combined.

In one embodiment, the gelcoat may be characterized by comprising an unsaturated polyester resin and a reactive solvent.

The unsaturated polyester resin as the above component refers to a resin obtained by esterifying an unsaturated polybasic acid such as maleic anhydride or phthalic anhydride, or an acid anhydride with a polyhydric alcohol such as propylene glycol, and the curing reaction of the resin occurs by radical polymerization. Radical polymerization reaches curing through the processes of decomposition, initiation, growth, termination, and chain transfer reaction. For example, the unsaturated polyester resin can be selected and used from among modified bisphenol resins, bisphenol resins, iso-based resins, ortho-based resins, terephthalic resins, and vinyl ester resins.

In one embodiment, the unsaturated polyester resin may be included in an amount of about 45 to 65 wt% based on 100 wt% of the entire gelcoat. If it is less than about 45 wt%, mechanical strength may decrease, and if it exceeds about 65 wt%, compatibility with other components may be impaired.

As the above components, the reactive solvent is selected from the group consisting of styrene monomer, butyl methyl methacrylate, 2-hydroxy ethyl methacrylate, butylacrylate, hydroxy ethyl acrylate, acrylic acid, methacrylic acid, dipropylene glycol diacrylate, hydroxy methacrylate, hydroxypropyl acrylate, hexanediol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, vinyltoluene, chlorostyrene, 2-phenoxy ethyl methacrylic acid, 2-phenoxyethyl acrylic acid, ethoxylated bisphenol A diacrylate, ethoxylated nonyl phenol acrylate, and mixtures thereof, and may preferably include a styrene monomer.

In one embodiment, the reactive solvent may be included in an amount of about 30 to 45 wt% based on 100 wt% of the entire gelcoat. If it is less than about 45 wt%, problems such as increased viscosity and deteriorated appearance may occur, and if it exceeds about 45 wt%, there is a high possibility of crystallization.

In one embodiment, the gelcoat may further include about 1 to 10 wt% of titanium dioxide as a filler and to enhance mechanical strength. If the titanium dioxide is included in an amount less than about 1 wt%, the mechanical strength may decrease, and if it exceeds about 10 wt%, the gelcoat may not be uniformly applied to the mold.

In one embodiment, the gelcoat may further include about 1 to 5 wt% of fumed silica as a filler and to enhance mechanical strength. If the fumed silica is included in an amount less than about 1 wt%, the mechanical strength may decrease, and if it exceeds about 5 wt%, porosity may be caused in the manufactured feed storage tank.

In one embodiment, the gelcoat can be mass-produced by shortening the curing time by additionally including about 0.1 to 1 wt% of a curing accelerator. The curing accelerator can be used without limitation as long as it can rapidly advance the curing time of the gelcoat including the unsaturated polyester resin and the styrene monomer, and may include, for example, a cobalt-based accelerator. Preferably, the curing accelerator may include cobalt bis(2-ethylhexanoate).

In one embodiment, if the curing accelerator is included in an amount of less than about 0.1 wt% of the gelcoat, the curing time shortening effect by the curing accelerator may not be sufficiently exerted, and if it exceeds about 1 wt%, workability may actually decrease.

In one embodiment, the gelcoat can exhibit high heat resistance, corrosion resistance, and thermal conductivity by additionally including about 0.1 to 1 wt% of aluminum nitride. The aluminum nitride is a ceramic material represented by the chemical formula of AlN, and is characterized by high heat resistance, corrosion resistance, and thermal conductivity. By additionally including the aluminum nitride in the mixture, it is possible to manufacture a feed storage tank that exhibits high heat resistance and is not easily deformed even under rapid temperature changes.

In one embodiment, if the aluminum nitride is included in an amount of less than about 0.1 wt%, the effect of improving heat resistance may not be sufficiently achieved, and if it exceeds about 1 wt%, the mixing property with other components may be impaired.

In one embodiment, the gelcoat can exhibit a pollutant adsorption and removal performance that causes an unpleasant odor by including activated carbon in an amount of about 0.1 to 1 wt%. If the activated carbon is included in an amount less than about 0.1 wt%, the pollutant adsorption and removal effect may not be sufficiently exhibited, and if it exceeds about 1 wt%, the gelcoat may not be uniformly coated on the mold.

The above activated carbon may include at least one selected from the group consisting of palm-based activated carbon, charcoal-based activated carbon, pitch-based activated carbon, granular activated carbon, impregnated activated carbon, powdered activated carbon, carbon fiber, and combinations thereof, and may specifically mean impregnated activated carbon.

In one embodiment, the impregnated activated carbon is one in which an impregnating material including one or more alkali metal hydroxides or carbonates is evenly impregnated and included in the activated carbon, for example, an impregnating material including one or more alkali metal hydroxides or carbonates selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, and combinations thereof may be evenly impregnated on the activated carbon by heating and stirring.

Next, the gel coat is cured to form the first layer.

The above curing may be performed at a temperature range of about 20°C to about 60°C for about 10 to 120 minutes. If the curing is performed at a temperature lower than about 20°C or for less than 10 minutes, the curing may not progress sufficiently, which may cause cracks or the like to occur later. In addition, if the temperature exceeds about 60°C or for more than about 120 minutes, the gel coat may not be uniformly cured. Preferably, the curing may be performed at a temperature of about 45°C to 55°C for about 10 to 30 minutes.

In one embodiment, the curing may be performed using a hot air method that raises the air temperature of a space being manufactured using a heating device such as a fan, or a convection method that raises the temperature of the radiator by using hot water or steam heated in a boiler installed in a separate location to raise the temperature of the air.

Next, glass fibers are attached to the first layer, a liquid composition including an unsaturated polyester resin is applied, and the liquid composition is cured to form a glass fiber layer. For example, after glass fibers are attached to the first layer, a liquid composition including an unsaturated polyester resin, a reactive solvent, and a curing agent is applied through a roller to cure the liquid composition together with the glass fibers to form glass fibers. Preferably, after glass fibers are attached to the first layer, a liquid composition is obtained by including a first agent including an unsaturated polyester resin and a reactive solvent and a second agent including a curing agent, and the liquid composition is applied through a roller to cure the liquid composition together with the glass fibers to form glass fibers.

The above glass fiber is included as a reinforcing agent to improve the mechanical strength of the unsaturated polyester resin, and can be laminated in the form of a chopped strand mat, a woven roving mat, a cloth mat, or a yarn mat. In addition, the glass fiber can be used in a mixture with a fiber selected from the group consisting of carbon fiber, basalt fiber, fiber manufactured from biomass, and combinations thereof.

In one embodiment, the curing agent may be used without limitation as long as it can cure the liquid composition, and may include, for example, at least one selected from the group consisting of dimethyl phthalate (1,2-benzenedicarboxylic acid, diethyl ester, Diethyl phthalate), methyl ethyl ketone peroxide, methyl ethyl ketone (2-butanone), and combinations thereof.

The above curing may be performed at a temperature range of about 20°C to about 60°C for about 10 to 120 minutes. If the above curing is performed at a temperature lower than about 20°C or for less than 10 minutes, the curing may not progress sufficiently, which may cause cracks to occur later. In addition, if the temperature exceeds about 60°C or for more than about 120 minutes, the gel coat may not be uniformly cured. Preferably, the curing during the manufacture of the glass fiber layer may be performed at a room temperature of 20°C to 30°C.

In one embodiment, the step of attaching glass fibers to the first layer and applying a liquid composition including an unsaturated polyester resin may be repeated 2 to 5 times. By repeating the steps of attaching glass fibers and applying a liquid composition, excellent mechanical strength can be exhibited.

In one embodiment, the unsaturated polyester resin may be included in an amount of about 45 to 65 wt% based on 100 wt% of the total first component of the liquid composition. If it is less than about 45 wt%, mechanical strength may decrease, and if it exceeds about 65 wt%, miscibility with other components may be impaired.

As the above-mentioned component, the reactive solvent may be a styrene monomer, and in one embodiment, the reactive solvent may be included in an amount of about 30 to 45 wt% based on 100 wt% of the total first agent of the liquid composition. If it is less than about 45 wt%, there are problems such as increased viscosity and deteriorated appearance, and if it exceeds about 45 wt%, there is a high possibility of crystallization.

In one embodiment, the second agent may be mixed in a ratio of about 200 to 300 g based on about 10 to 20 L of the first agent.

Next, a gel coat containing an unsaturated polyester resin and a reactive solvent is applied to the glass fiber layer and cured to form a second layer.

In one embodiment, the gel coat applied to the glass fiber layer may be different from the gel coat applied to the inner surface of the mold. For example, a first gel coat may be applied to the inner surface of the mold and cured to form a first layer, a glass fiber layer may be formed on the first layer, and a second gel coat may be applied to the glass fiber layer and cured to form a second layer.

In one embodiment, the unsaturated polyester resin may be included in an amount of about 45 to 65 wt% based on 100 wt% of the total weight of the second gelcoat. If it is less than about 45 wt%, mechanical strength may decrease, and if it exceeds about 65 wt%, compatibility with other components may be impaired.

As the above components, the reactive solvent is selected from the group consisting of styrene monomer, butyl methyl methacrylate, 2-hydroxy ethyl methacrylate, butylacrylate, hydroxy ethyl acrylate, acrylic acid, methacrylic acid, dipropylene glycol diacrylate, hydroxy methacrylate, hydroxypropyl acrylate, hexanediol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, vinyltoluene, chlorostyrene, 2-phenoxy ethyl methacrylic acid, 2-phenoxyethyl acrylic acid, ethoxylated bisphenol A diacrylate, ethoxylated nonyl phenol acrylate, and mixtures thereof, and may preferably include a styrene monomer.

In one embodiment, the reactive solvent may be included in an amount of about 30 to 45 wt% based on 100 wt% of the entire second gelcoat. If it is less than about 45 wt%, problems such as increased viscosity and deteriorated appearance may occur, and if it exceeds about 45 wt%, there is a high possibility of crystallization.

In one embodiment, the second gelcoat may further include about 1 to 10 wt% of titanium dioxide as a filler and to enhance mechanical strength. If the titanium dioxide is included in an amount less than about 1 wt%, the mechanical strength may decrease, and if it exceeds about 10 wt%, the gelcoat may not be uniformly applied to the mold.

In one embodiment, the second gelcoat can exhibit high heat resistance, corrosion resistance, and thermal conductivity by additionally including about 0.1 to 1 wt% of aluminum nitride. The aluminum nitride is a ceramic material represented by the chemical formula of AlN, and is characterized by high heat resistance, corrosion resistance, and thermal conductivity. By additionally including the aluminum nitride in the mixture, it is possible to manufacture a feed storage tank that exhibits high heat resistance and is not easily deformed even under rapid temperature changes.

In one embodiment, the second gelcoat may exhibit a pollutant adsorption and removal performance that causes an odor by including about 0.1 to 1 wt% of the impregnated activated carbon. If the impregnated activated carbon is included in an amount less than about 0.1 wt%, the pollutant adsorption and removal effect may not be sufficiently exhibited, and if it exceeds about 1 wt%, the gelcoat may not be uniformly coated on the mold.

Next, the feed storage tank is obtained by demolding from the mold.

In one embodiment, the method may further include, after the step of obtaining a feed storage tank by demolding from the mold, a step of reapplying a gel coat to a portion of the obtained feed storage tank that requires maintenance and curing the same. For example, after the step of obtaining a feed storage tank by demolding from the mold, a step of reapplying a gel coat to a joint portion between the left mold and the right mold and curing the same may be further included. The joint portion between the molds may be sanded to make it smooth, and then the first gel coat may be reapplied to fill a gap that may exist in the joint portion to enhance sealing force.

In one embodiment, the step of applying a gel coat to the inner surface of the mold may include performing a masking process on a part of the inner surface of the mold and applying the gel coat, and the step of attaching glass fibers to the first layer and applying a liquid composition including an unsaturated polyester resin may include performing a masking process after attaching the glass fibers and applying the liquid composition including an unsaturated polyester resin, thereby forming a transparent window in the feed storage tank. That is, after masking the inner surface of the mold using a tape and coating the gel coat, and then re-masking the same position using a tape after attaching the glass fibers, the coating process is performed so that the portion is not coated, so that the internal environment of the feed storage tank can be observed later through the transparent window. At this time, the tape used for the masking process may be characterized in that it is a special tape that can withstand heat during the curing process.

In one embodiment, the above-described effects and advantages are achieved by the organic interaction of all of the above-described components and component steps, and thus, the above-described effects may not be achieved if the above-described components and component steps are selectively included.

Hereinafter, the configuration of the present invention and the effects thereof will be described in more detail through specific examples and comparative examples. However, these examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited to these examples.

[Examples 1 to 3]

First, a semicircular mold having a left mold and a right mold that are symmetrical to each other in the left-right direction and exhibit a tank shape when combined was manufactured, and a first gel coat manufactured by mixing the components shown in Table 1 below was applied to the inside of the left mold and the right mold. Curing was performed at 50° C. for about 15 minutes to form a first layer. After attaching glass fiber to the formed first layer, a liquid composition was applied by mixing 18 L of the first agent containing 60 wt% of an unsaturated polyester resin and 40 wt% of a styrene monomer and 300 g of the second agent containing 59 wt% of dimethyl phthalate, 38 wt% of methyl ethyl ketone peroxide, and 3 wt% of methyl ethyl ketone, and curing at room temperature for about 30 minutes to form a glass fiber layer. The steps of attaching the glass fiber and applying the liquid composition were repeated three times.

After the formation of the glass fiber layer, the second gel coat manufactured by mixing the components of Table 2 below was applied, and cured at 50° C. for about 15 minutes to form a second layer. After the feed storage tank was removed from the mold, the surface was sanded, and the first gel coat was applied to the joint area between the left and right molds, and cured at 50° C. for about 15 minutes to fill the gap and repair it. The feed storage tanks manufactured according to the type of gel coat used were named Example 1, Example 2, and Example 3, respectively.

1st gelcoat composition (weight%) Example 1 Example 2 Example 3 Unsaturated polyester resin 55.00 55.00 55.00 styrene monomer 35.00 34.75 34.5 Titanium Dioxide 5.00 5.00 5.00 Fumed silica 4.50 4.50 4.55 Cobalt bis(2-ethylhexanoate) 0.50 0.50 0.50 Aluminum nitride 0.00 0.25 0.25 Lithium hydroxide impregnated activated carbon 0.00 0.00 0.20 total 100.00 100.00 100.00

Second gelcoat composition (weight%) Example 1 Example 2 Example 3 Unsaturated polyester resin 59.50 60.00 60.00 styrene monomer 34.50 35.00 35.00 Titanium Dioxide 5.80 4.65 4.60 Aluminum nitride 0.00 0.15 0.10 Lithium hydroxide impregnated activated carbon 0.00 0.00 0.10 Pigment 0.20 0.20 0.20 total 100.00 100.00 100.00

[Comparative example]

First, a semicircular mold having a left mold and a right mold that are symmetrical to each other in the left-right direction and exhibit a tank shape when combined was manufactured, and a liquid composition containing 18 L of a first agent containing 60 wt% of an unsaturated polyester resin and 40 wt% of a styrene monomer and 300 g of a second agent containing 59 wt% of dimethyl phthalate, 38 wt% of methyl ethyl ketone peroxide, and 3 wt% of methyl ethyl ketone was mixed and applied to the inside of the left mold and the right mold, and the mixture was cured at room temperature for about 30 minutes to form a first layer. Glass fiber was applied to the first layer, and the same liquid composition was applied and cured to form a glass fiber layer. The step of forming the glass fiber layer was repeated three times, and the feed storage tank was demolded from the mold, and the surface was sanded to finish, thereby obtaining a feed storage tank of a comparative example.

[Experimental Example 1: Mechanical strength measurement]

The mechanical strength of the feed storage tanks manufactured in the above Examples 1 to 3 and Comparative Examples was measured. The measurement method was as follows: First, a plate-shaped mold measuring 30 cm in width and 30 cm in length was manufactured, and then a feed storage tank specimen was manufactured in the same manner as in the above Examples and Comparative Examples. For each specimen, the tensile strength (ASTM D638), flexural strength (ASTM D790), flexural modulus (ASTM D790), and impact strength (ASTM D256) were measured according to standard test methods (ASTM, etc.), and the results are shown in Table 3.

　 Example 1 Example 2 Example 3 Comparative example Tensile strength (kgf/cm ² ) 1050 1080 1230 820 Flexural strength (kgf/cm ² ) 1310 1420 1570 1030 Flexural modulus (kgf/cm ² ) 52000 54000 58000 52000 Impact strength (kgfcm/cm) 5 5.5 5.9 4.4

As shown in Table 3 above, it was confirmed that the feed storage tank manufactured by the method according to the present invention exhibited superior mechanical strength compared to the comparative example.

[Experimental Example 2: Measurement of water resistance and chemical resistance]

The water resistance and chemical resistance of the feed storage tanks manufactured in the above Examples 1 to 3 and Comparative Examples were measured. The measurement method was as follows: First, a plate-shaped mold measuring 30 cm in width and 30 cm in length was manufactured, and then a feed storage tank specimen was manufactured in the same manner as in the above Examples and Comparative Examples. Each specimen was immersed in salt water having a salt concentration of 35‰ and a sulfuric acid solution having a concentration of 2% for 1 hour every day, and whether the surface of the reinforcing material was damaged was checked every day for 60 days. The results of checking the date of damage are shown in Table 4 below.

item Example 1 Example 2 Example 3 Comparative example Salt water (35‰) 58 - (Undamaged) - (Undamaged) 48 Sulfuric acid solution (2%) 37 42 56 17

As shown in Table 4 above, it was confirmed that the feed storage tank manufactured by the method according to the present invention exhibited superior water resistance and chemical resistance compared to the comparative example.

[Experimental Example 3: Measurement of insulation properties]

The insulation properties of the feed storage tanks manufactured in the above Examples 1 to 3 and Comparative Examples were measured. The measurement method was as follows: First, a plate-shaped mold measuring 30 cm in width and 30 cm in length was manufactured, and then a feed storage tank specimen was manufactured in the same manner as in the above Examples and Comparative Examples. For each specimen, an insulation performance test was conducted based on the total calorific value measurement. The results are shown in Table 5 below.

classification Total calorific value (MJ/m ² ) Example 1 4.5 Example 2 4.9 Example 3 5.2 Comparative example 3.7

As shown in Table 5 above, the feed storage tank manufactured by the method according to the present invention exhibited a lower total calorific value than the comparative example, indicating excellent insulation performance, and thus, it was confirmed that feed could be stably stored even in rapid environmental changes.

Although this specification describes only a few examples among various embodiments performed by the inventors of the present invention, the technical idea of the present invention is not limited or restricted thereto, and can be modified and implemented in various ways by those skilled in the art.

Claims (5)

A step for preparing a mold, characterized in that it comprises a left mold and a right mold which are symmetrical to each other in the left-right direction and exhibit a tank shape when combined;
A step of applying a first gel coat to the inner surface of the mold;
A step of forming a first layer by curing the first gel coat at a temperature range of 45°C to 55°C for 10 to 30 minutes;
A step of attaching glass fiber to the first layer;
A step of obtaining a liquid composition by mixing 10 to 20 L of a first agent containing an unsaturated polyester resin and a styrene monomer and 200 to 300 g of a second agent containing a curing agent;
A step of repeatedly applying the liquid composition onto the first layer to which the glass fiber is attached two to five times;
A step of forming a glass fiber layer by curing the liquid composition at 20°C to 30°C for 10 to 120 minutes;
A step of applying a second gel coat to the above glass fiber layer;
A step of curing the second gel coat to form a second layer;
A step of obtaining a feed storage tank by demolding from the above mold; and
A step of reapplying the first gel coat or the second gel coat to a part of the feed storage tank requiring maintenance and curing it; including,
The step of applying a gel coat to the inner surface of the mold is to perform masking treatment on a part of the inner surface of the mold and apply a gel coat.
The step of attaching glass fiber to the first layer and applying a liquid composition is to attach the glass fiber, perform masking treatment, and apply a liquid composition to form a transparent window in the feed storage tank.
The first gelcoat comprises 45 to 65 wt% of an unsaturated polyester resin, 30 to 45 wt% of a styrene monomer, 1 to 10 wt% of titanium dioxide, 1 to 5 wt% of fumed silica, 0.1 to 1 wt% of cobalt bis(2-ethylhexanoate), and 0.1 to 1 wt% of aluminum nitride.
A method for manufacturing a feed storage tank, characterized in that the second gelcoat comprises 45 to 65 wt% of an unsaturated polyester resin, 30 to 45 wt% of a styrene monomer, 1 to 10 wt% of titanium dioxide, and 0.1 to 1 wt% of aluminum nitride. delete delete delete delete