KR20220054505A - A polyurethane foam for liquefied gas storage tank and manufacturing method thereof - Google Patents

Abstract

The present invention provides a polyurethane foam for a liquefied gas storage tank comprising a polyol-containing compound, an isocyanate-containing compound, and glass bubbles. According to the present invention, the mechanical strength and insulation performance of polyurethane foam can be dramatically improved, and through the same, the thickness can be reduced compared to conventional insulation materials, thereby increasing the volume space of a fuel in a storage tank.

Description

Polyurethane foam for liquefied gas storage tank and manufacturing method thereof

The present invention relates to a polyurethane foam for a liquefied gas storage tank and a method for manufacturing the same, and more particularly, to a polyurethane foam for a liquefied gas storage tank that can improve the mechanical strength and thermal insulation performance of an insulating material applied to a liquefied gas storage tank. and to a method for manufacturing the same.

Recently, as energy storage and transportation-related technologies are drawing attention around the world due to environmental problems, research on cryogenic insulation materials for liquefying and storing gases such as natural gas, nitrogen, hydrogen and helium is being actively conducted around the world.

In particular, as regulations on exhaust gas from ships continue to be strengthened, the use of natural gas and hydrogen is spotlighted as a solution.

Since natural gas and hydrogen have a cryogenic liquefaction temperature, the development of adiabatic storage technology is essential to efficiently store and transport them.

On the other hand, polyurethane foam is currently used as an insulating material for insulation in a liquefied gas storage tank for storing cryogenic fuel, and research to improve the performance of the polyurethane foam is continuously being made.

Polyurethane foam is a porous material that insulates through the pores in the polyurethane foam, and transmits or resists a load through a structure that maintains the pores.

In addition, in order to increase the strength of the polyurethane foam, the density can be adjusted. When the density is increased, the density of the structure increases and the strength can be increased. The performance is deteriorated, which leads to an increase in the thickness of the insulating material, thereby reducing the volumetric volume of the fuel.

The reduction in the thickness of the insulation in the liquefied gas storage tank provided in the ship can act as a great advantage in increasing the cargo and fuel loading of the space-limited ship.

In addition, in order to improve the storage space, mechanical performance to withstand the sloshing load caused by the movement of liquid cargo and thermal insulation performance to reduce the vaporization rate of fuel must be secured.

Accordingly, it is possible to satisfy the mechanical properties required by the structural load and temperature characteristics of the liquefied gas storage tank for storing cryogenic fuel of a ship, and it is equipped with improved mechanical strength and thermal insulation performance to develop a technology for efficient fuel transport I need this.

Registered Patent No. 10-1004963 (Registration date: December 23, 2010) "Polyurethane foam using eco-friendly foaming agent and cryogenic insulation for LPG vessels using the same"

In the present invention, polyurethane foam for a liquefied gas storage tank and a method for manufacturing the same, specifically, by improving the mechanical strength and thermal insulation performance of the polyurethane foam, it is possible to reduce the thickness compared to the conventional insulation material, and through this, the volume of fuel in the storage tank To provide a polyurethane foam for a liquefied gas storage tank that can increase the space.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

In order to solve the above problems, the present invention provides a polyurethane foam for a liquefied gas storage tank comprising a polyol-containing compound, an isocyanate-containing compound and a glass bubble.

On the other hand, in another aspect of the present invention for solving the above-mentioned problems, the step of mixing an isocyanate-containing compound with a glass bubble to produce an intermediate mixture, adding a polyol-containing compound and a blowing agent to the intermediate mixture and stirring the polymer It provides a method for producing a polyurethane foam for a liquefied gas storage tank comprising the steps of producing a mixture and injecting a polymer mixture into a mold to prepare a polyurethane foam.

Polyurethane foam for a liquefied gas storage tank according to an embodiment of the present invention is an isocyanate-containing compound, a polyol-containing compound, a foaming agent and a glass bubble, preferably a glass bubble having a density of 0.1 g/cc to 0.3 g/cc isocyanate-containing compound By adding 1 to 3 parts by weight based on 100 parts by weight of the polyurethane foam to form a polyurethane foam, the mechanical strength and thermal insulation performance of the polyurethane foam can be remarkably improved, and through this, the thickness can be reduced compared to the conventional insulation material, so that the storage tank I can increase the volumetric space of my fuel.

Furthermore, polyurethane foam can be manufactured by further including glass fibers to easily resist the bending load of the hull, and through this, the compressive strength and tensile strength of the polyurethane foam used as an insulator of the liquefied gas storage tank can be further improved. can be improved

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

1 is a flowchart illustrating a manufacturing process of polyurethane for a liquefied gas storage tank according to an embodiment of the present invention.
2 is a photograph of the glass bubble polyurethane foam prepared according to the first embodiment of the present invention with a scanning electron microscope (SEM).
Figure 3 is a stress-strain diagram of the glass bubble polyurethane foam and the polyurethane foam manufactured according to the first embodiment of the present invention.
4 is a view showing the stress-strain diagram for the tensile test results of the glass bubble glass fiber polyurethane foam and the glass fiber polyurethane foam manufactured according to the second embodiment of the present invention.
5 is a view showing a stress-strain diagram for the compression test results of the glass bubble glass fiber polyurethane foam and the glass fiber polyurethane foam manufactured according to the second embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION The detailed description set forth below in conjunction with the appended drawings is intended to describe exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced.

In order to clearly explain the present invention in the drawings, parts not related to the description may be omitted, and the same reference numerals may be used for the same or similar components throughout the specification.

In an embodiment of the present invention, expressions such as “or” and “at least one” may indicate one of the words listed together, or a combination of two or more.

Polyurethane foam for a liquefied gas storage tank according to an embodiment of the present invention is an insulator applied to a liquefied gas storage tank for storing cryogenic liquefied gas, and includes an auxiliary agent such as glass bubble, to the conventional polyurethane foam insulation. Compared to that, the thickness can be reduced, and mechanical strength and thermal insulation performance can be remarkably improved.

Specifically, the polyurethane foam for a liquefied gas storage tank according to an embodiment of the present invention includes an isocyanate-containing compound, a polyol-containing compound, a foaming agent and a glass bubble, and can be manufactured through this.

The isocyanate-containing compound reacts with a polyol to form a urethane group, and may consist of an aliphatic, cycloaliphatic or aromatic polyfunctional isocyanate known in the art, and preferably an aromatic polyfunctional isocyanate.

Polyfunctional isocyanates of this type are known in the art or obtainable by methods known in the art.

At this time, the polyfunctional isocyanate may be used as a mixture, and may have two isocyanate groups (hereinafter referred to as 'diisocyanate') or more groups per molecule.

More specifically, although not necessarily limited thereto, the isocyanate-containing compounds described above include alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as dodecane 1,12-diisocyanate, 2-ethyltetramethylene 1 ,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate, preferably hexamethylene 1,6-diisocyanate; Cycloaliphatic diisocyanates such as cyclohexane 1,3- and 1,4-diisocyanate and also any mixtures of the above isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), hexahydrotolylene 2,4- and 2,6-diisocyanate and also the corresponding isomer mixtures, dicyclohexylmethane 4,4′-, 2,2′- and 2,4′-diisocyanate and Also the corresponding isomer mixtures, preferably aromatic polyisocyanates such as tolylene 2,4- and 2,6-diisocyanate and the corresponding isomer mixtures, diphenylmethane 4,4'-, 2,4'- and 2, 2'-diisocyanates and mixtures of the corresponding isomers, diphenylmethane 4,4'- and 2,2' diisocyanates, mixtures of polyphenylpolymethylene polyisocyanates, diphenylmethane 4,4'-, 2,4'- and mixtures of 2,2'-diisocyanate and polyphenylpolymethylene polyisocyanate (crude MDI) and mixtures of crude MDI and tolylene diisocyanate.

The polyol-containing compound is a liquid high molecular material in which two or more alcohol groups are attached to a hydrocarbon chain, and may be composed of polyether polyol or polyester polyol.

More specifically, the polyether polyol is ethylene glycol, 1,2-propane glycol, 1,3-propylene glycol, butylene glycol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 2-methyl -1,3-propanediol, glycerol, trimethylolpropane, 1,2,3-hexanetriol, 1,2,4-butanetriol, trimethylolmethane, pentaerythritol, diethylene glycol, triethylene glycol, Polyethylene glycol, tripropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, sorbitol, sucrose, hydroquinone, resorcinol, catechol, bisphenol, or two or more polyols and ethylene oxide, propylene oxide or It may be prepared by polymerizing a mixture thereof.

In addition, the polyester polyol may be prepared by polymerizing phthalic anhydride or dipic acid with ethylene oxide, propylene oxide, or a mixture thereof.

The foaming agent is used for foaming of polymer composite materials. It is a substance that forms bubbles during a polymer reaction, and is a physical foaming agent and chemical foaming agent that vaporizes (sublimes) by the heat of reaction to form bubbles (reacts with isocyanate to generate carbon dioxide) ) can be used alone or in combination.

Here, the physical foaming agent is vaporized (sublimated) by the heat of reaction, and the resulting gas is surrounded by the cells of the foam, so that the manufactured foam may exhibit low thermal conductivity.

At this time, although not particularly limited thereto, hydrocarbon-based C-pentane, hydrochlorofluorocarbon-based HCFC-141b (1,1-dichloro-1-fluoroethane), and hydrofluorocarbon (HFC)-based HFC-245fa (1, 1,1,3,3-pentafluoropropane), HFC-365mfc (1,1,1,3,3-pentafluorobutane), mixed HFC-365mfc/227ea (1,1,1,3,3- It may be preferable to use pentafluorobutane/1,1,1,2,3,3,3-heptafluoropropane), mixtures thereof, etc. as blowing agents.

The amount of the physical foaming agent can be determined according to the required characteristics such as the density of the polyurethane foam to be manufactured, for example, 30 parts by weight or less, preferably 3 to 25 parts by weight, based on 100 parts by weight of the polyol-containing compound; More preferably, it may be in the range of 4 to 20 parts by weight.

In addition, since the chemical foaming agent foams from carbon dioxide generated by reaction with water or the like using the activity of isocyanate, water may be used as the foaming agent.

In this case, the amount of water used may be in the range of 0 to 10 parts by weight, more preferably 0 to 5 parts by weight, based on 100 parts by weight of the polyol-containing compound.

The glass bubble may be formed in a bead shape and may have a hollow shell structure, or may be formed as a low-density glass bubble.

Glass bubble is a white powder-type microsphere material with a particle size of 0.01 to 100 μm. It has a very light density of 0.1 to 0.6 g/cc and a thermal conductivity of 0.04 to 0.2 W/mK, so it can be applied to insulation, paints and coatings. and the strength is 250 to 28000 psi, and it can be used for the purpose of improving the strength.

Such a glass bubble can be formed by adjusting the diameter according to the required physical properties of the product to be applied, and when applied to the polyurethane foam of this embodiment, as a preferred example, 0.1 g/cc to 0.3 g to improve mechanical strength and thermal insulation performance It can be formed at a density of /cc.

More specifically, the inside of the glass bubble is empty and the shell portion may be formed of a glass bubble made of Soda Lime Borosilicate Glass or silica (SiO2) having a thickness of 50 nm to 300 nm.

Since the inside of these glass bubbles is empty, they can be formed with a relatively low density compared to general Soda Lime Borosilicate Glass or silica (SiO₂) formed with a dense core.

In addition, the glass bubble may be included in an amount of 1 to 3 parts by weight based on 100 parts by weight of the isocyanate-containing compound.

As described above, the polyurethane foam for the liquefied gas storage tank of this embodiment may be prepared by adding a foaming agent to the intermediate mixture in which the glass bubble is added isocyanate-containing compound and the polyol-containing compound are mixed, and the prepared polyurethane foam By interposing a glass bubble serving as a reinforcement in the pores between the cells constituting the silver foam, the density of the structure may increase and thermal conductivity may be lowered, thereby improving the mechanical strength and thermal insulation performance of the polyurethane foam.

On the other hand, below, the manufacturing process of the polyurethane foam for a liquefied gas storage tank configured as described above will be described in more detail.

1 is a flowchart illustrating a manufacturing process of polyurethane for a liquefied gas storage tank according to an embodiment of the present invention.

Referring to FIG. 1 , a glass bubble may be added to the isocyanate-containing compound and stirred (S110).

In this process, 1 to 3 parts by weight of glass bubbles are added to the isocyanate-containing compound based on 100 parts by weight of the isocyanate-containing compound, and the glass bubbles are mixed with the isocyanate-containing compound by physically stirring through a stirrer.

In this case, it can be stirred at a low speed of 3000 rpm or less for 3 minutes using a mechanical stirring device such as a homogenizer.

If the stirring is performed at a speed exceeding 3000 rpm, the possibility of damage to the glass bubble such as breakage of the glass bubble is greatly increased, and the degree of residual micropores in the solution is greatly increased according to the stirring, and unnecessary pores are formed in the subsequent foaming step can be

Next, a polyol-containing compound and a foaming agent may be added to the intermediate mixture in which the isocyanate-containing compound is mixed with glass bubbles and stirred (S120).

In this stirring process, the isocyanate-containing compound may react with the polyol-containing compound to form a urethane group.

In this case, the polyol-containing compound may be added in an amount of 83 to 91 parts by weight based on 100 parts by weight of the isocyanate-containing compound.

In addition, the foaming agent is added for foaming of the polymer composite material, and as an example, when HFC-245fa is used as the foaming agent, it may be added in an amount of 4 to 12 parts by weight based on 100 parts by weight of the polyol-containing compound.

In addition, in the process of mixing and stirring by adding the polyol-containing compound and the foaming agent to the intermediate mixture as described above, it can be stirred at a speed of 5000 rpm for 1 minute using a mechanical stirring device, through which the glass bubble is mixed with the isocyanate-containing compound It is possible to form a polymer mixture in which the intermediate mixture, the polyol-containing compound, and the blowing agent are mixed.

At this time, as an example, the stirring as described above is preferably performed at a speed of 5000 rpm or less in a temperature range of 10 to 40 ° C. Conversely, when the temperature exceeds the above range, a problem in which the reaction proceeds too quickly may occur. there is.

Then, the polymer mixture prepared as described above may be injected into the mold to prepare a glass bubble polyurethane foam (S130).

In this case, a mold corresponding to the size and shape of the polyurethane foam to be molded is provided, and a release agent can be applied to the surface in contact with the polymer mixture in the mold in advance, and then the polymer mixture is injected into the mold to form the polyurethane foam can be manufactured.

In addition, in the process of manufacturing the polyurethane foam, the mold in which the polymer mixture is injected can be accommodated in the control device, and the foaming conditions and environment for molding the polyurethane foam can be adjusted through the control device.

As an example, the control device may include a chamber accommodating the mold therein, a thermometer and a hygrometer installed in the chamber, a heat inlet and a circulator provided at one side of the chamber, and a circulator for circulating air in the chamber.

Accordingly, the mold in which the polymer mixture is injected can be accommodated in the chamfer, the temperature inside the chamber can be controlled through the heat inlet, and the air in the chamber can be circulated through the circulator by checking the thermometer and the hygrometer.

At this time, as the foaming conditions for molding the polyurethane foam, it is preferable to maintain the internal temperature of the chamber in the range of 25° C. to 40° C., and the humidity at 70% or less.

As such, the polyurethane foam according to this embodiment can be prepared by adding a foaming agent and glass bubble to an intermediate mixture in which an isocyanate-containing compound and a polyol-containing compound are mixed, and mechanical strength and heat insulation by controlling temperature and humidity during the foaming process It is possible to uniformly control the shape of the cell that affects the performance.

In addition, the polyurethane foam according to the present embodiment, since the glass bubble is filled in the space between the cells of the foam and cells, the thermal conductivity is lower than that of the conventional heat insulator, and the compressive strength can have improved performance.

On the other hand, the polyurethane foam for a liquefied gas storage tank according to an embodiment of the present invention may further include a fiber reinforcement.

Fiber reinforcement is for further strengthening the mechanical strength of polyurethane foam, and synthetic fibers such as glass fibers, polyamides, polyesters, etc., and inorganic fibers such as carbon fibers and ceramic fibers, etc. may be used. In particular, laminated glass fiber mats It is preferable to use a sieve.

The fiber reinforcing material is preferably 5 to 40 parts by weight based on 100 parts by weight of the polyol-containing compound.

At this time, if the content of the glass fiber is less than 5 parts by weight of the polyol-containing compound, the low-temperature shrinkage stability and the effect of preventing cracks are reduced, and if it exceeds 40 parts by weight, abnormal foaming of the foam and the foam Cracking may occur.

In the manufacturing process of the polyurethane foam according to this embodiment, as an example, the polyurethane solution prepared by the manufacturing process of the first embodiment described above (a polymer mixture comprising an isocyanate-containing compound, a glass bubble, a polyol-containing compound and a blowing agent) It can be prepared by impregnating the glass fiber mat laminate.

On the other hand, below, the polyurethane foam prepared according to the preferred embodiment and comparative example of the present invention will be described.

However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

1. Polyurethane Foam Manufacturing

[Example 1]

Based on 100 parts by weight of the methylene diphenyl diisocyanate (MDI)-containing compound, 2 parts by weight of soda lime borosilicate glass having a density of 0.1 g/cc was mixed, followed by stirring at a low speed of 3000 rpm for 3 minutes using a mechanical stirring device.

Thereafter, 91 parts by weight of the polyol-containing compound based on 100 parts by weight of the MDI-containing compound and 7 parts by weight of a blowing agent (HFC-245fa) based on 100 parts by weight of the polyol-containing compound were added, and then together with a catalyst (CF3CH2CHF2) at room temperature After stirring at 5000 rpm for 1 minute using a mechanical stirring device, polyurethane foam was prepared in a mold.

The reaction temperature in the stirring step was 15°C to 25°C, and stirring was performed using a general manual rotary stirring device.

[Comparative Example 1]

A polyurethane foam was prepared in the same manner as in Example 1, except that glass bubbles were not added.

The results of measuring the compressive strength and thermal conductivity of the glass bubble polyurethane foam prepared according to Example 1 and Comparative Example 1 are shown in Table 1 below.

division Example 1 Comparative Example 1
Compressive strength (MPa)
(20℃) 1.653 1.358 Compressive strength (MPa)
(-163℃) 4.25 3.618 thermal conductivity
(W/mK) 0.03247 0.0349 density
(Kg/m3) 130 130

Referring to Table 1, the polyurethane foam to which glass bubbles are added according to an embodiment of the present invention has the same density at room temperature and 163 degrees below zero where liquefied gas is stored, respectively, compared to the comparative example in which glass bubbles are not added. It can be seen that the compressive strength is greatly increased and the thermal conductivity is greatly decreased.

2. Manufacturing of glass fiber polyurethane foam

[Example 2]

A glass bubble glass fiber polyurethane foam was prepared by impregnating the glass fiber mat laminate with the polyurethane solution (polymer mixture containing isocyanate, glass bubble and polyol) prepared in the same manner as in Example 1.

[Comparative Example 2]

A glass fiber polyurethane foam was prepared by impregnating a glass fiber mat laminate with a polyurethane solution (a polymer mixture containing isocyanate and polyol) prepared in the same manner as in Comparative Example 1.

The results of measuring the compressive strength and thermal conductivity of the glass bubble glass fiber polyurethane foam prepared according to Example 2 and Comparative Example 2 are shown in Table 2 below.

division Example 2 Comparative Example 2
Compressive strength (MPa)
(20℃) 0.837 0.739 Tensile strength (MPa)
(20℃) 2.145 1.477 Compressive strength (MPa)
(-163℃) 1.756 1.518 Tensile strength (MPa)
(-163℃) 2.276 2.181 thermal conductivity
(W/mK) 0.025 0.025 density
(kg/m3) 110 110

Referring to Table 2, the glass fiber polyurethane foam to which glass bubbles are added according to Example 2 of the present invention is compared to Comparative Example 2 in which glass bubbles are not added, at room temperature and 163 degrees below zero where liquefied gas is stored, respectively. , it can be seen that the compressive strength and tensile strength are greatly increased while maintaining the thermal conductivity within the same density.

Meanwhile, FIG. 2 is a photograph taken with a scanning electron microscope (SEM) of the glass bubble polyurethane foam prepared according to the first embodiment of the present invention.

Referring to FIG. 2, it can be seen that glass bubbles are located between the cells (generated by the isocyanate-containing compound and the polyol-containing compound) constituting the polyurethane foam, and heat conduction is improved because heat inflow is suppressed due to the hollow glass bubble. It can be lowered, and the glass bubble provided between the cells acts as a reinforcing material, so that the improvement of mechanical strength can also be ensured.

Figure 3 is a stress-strain diagram of the glass bubble polyurethane foam and the polyurethane foam manufactured according to the first embodiment of the present invention.

3, in order to evaluate the mechanical performance of the glass bubble polyurethane foam (Example 1) and the polyurethane foam (Comparative Example 1) prepared according to the above-described embodiment, compression tests were performed at room temperature and cryogenic temperature, As a result, it can be seen that the glass bubble polyurethane foam has improved strength compared to the polyurethane foam.

4 is a view showing a stress-strain diagram for the tensile test results of the glass bubble glass fiber polyurethane foam and the glass fiber polyurethane foam manufactured according to the second embodiment of the present invention, and FIG. 5 is the second embodiment of the present invention. It is a view showing the stress-strain curve for the compression test results of the glass bubble glass fiber polyurethane foam and the glass fiber polyurethane foam manufactured according to the embodiment.

4 and 5, in order to evaluate the mechanical performance of the glass bubble glass fiber polyurethane foam (Example 2) and the glass fiber polyurethane foam (Comparative Example 2) prepared according to the above-described embodiment, room temperature and cryogenic temperature Tensile test was performed in , and as a result, it can be confirmed that the glass bubble glass fiber polyurethane foam has significantly improved tensile strength and compressive strength compared to the glass fiber polyurethane foam.

As described above, the polyurethane foam for a liquefied gas storage tank according to an embodiment of the present invention is an isocyanate-containing compound, a polyol-containing compound, a foaming agent and a glass bubble, preferably 1 to 100 parts by weight of the isocyanate-containing compound. By forming using 3 parts by weight of glass bubbles (0.1 g/cc to 0.3 g/cc), the mechanical strength and thermal insulation performance of the polyurethane foam can be remarkably improved, and through this, the thickness of the insulating material compared to the conventional insulating material It is possible to reduce the volumetric space of the fuel in the storage tank.

Furthermore, polyurethane foam can be manufactured by further including glass fibers to easily resist the bending load of the hull, and through this, the compressive strength and tensile strength of the polyurethane foam used as an insulator of the liquefied gas storage tank can be further improved. can be improved

The embodiments of the present invention disclosed in the present specification and drawings are merely provided for specific examples in order to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention.

Therefore, the scope of the present invention should be construed as including all changes or modifications derived based on the technical spirit of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

Claims (2)

polyol containing compounds;
isocyanate-containing compounds; and
Polyurethane foam for liquefied gas storage tank containing glass bubbles.
mixing the isocyanate-containing compound with glass bubbles to form an intermediate mixture;
adding a polyol-containing compound and a blowing agent to the intermediate mixture and stirring to form a polymer mixture; and
A method of producing a polyurethane foam for a liquefied gas storage tank comprising the step of preparing a polyurethane foam by injecting the polymer mixture into a mold.

Images