KR101771966B1 - Construction Method for Suppressing Crack Formation of Urethane Foam-based Insulator in Refrigeration Warehouses - Google Patents

Abstract

Disclosed is a construction method of effectively restraining crack formation of an insulation material, spray-coating a raw material to form urethane foam on a wall of a cold storage at time intervals in a lattice pattern through a zigzag method; and using one or more technical elements to absorb (or remove) contraction effects induced under an operation condition inside the cold storage in a process of spray-coating in order to effectively restrain crack formation of an insulation material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing crack formation in a urethane foam material in a freezing warehouse,

The present invention relates to a construction method for suppressing the formation of cracks in a heat insulating material made of a urethane foam material in a freezing warehouse. More specifically, the present invention relates to a method of spray coating a urethane foam-forming raw material on a wall of a freezing warehouse in a zigzag manner in a lattice pattern with a time difference, and further to absorb the shrinkage phenomenon caused under operating conditions in a freezing warehouse Which is capable of effectively suppressing the formation of cracks in the heat insulating material by introducing one or more technical elements for spray coating.

Recently, there has been a rapid increase in the necessity of low temperature storage or storage technology in accordance with the improvement of living standard and change of eating patterns, advancement of logistics distribution structure, increase of low temperature logistics, activation of courier service industry, integration and enlargement of logistics centers . In addition, in a situation where the market environment is changing due to market opening, domestic agriculture and livestock products are required to maintain long - term storage and storage quality in order to secure market competitiveness. Therefore, for long-term storage of various agricultural and livestock products, the spread of low-temperature storage facilities, especially freezing warehouses, is rapidly increasing. In this regard, the freezer warehouse may be classified as Class C, Class F, and Class SF according to the room temperature set according to the storage.

Generally, the freezing warehouse is an independent structure, its walls, ceilings and floors are installed to keep indoor temperature and humidity at a constant level by intercepting hot air of outside air, especially in summer. For example, the refrigeration warehouse can be maintained at a low temperature of -60 to -18 占 폚. In order to keep the internal space of the freezer compartment at a low temperature, it is necessary to block heat exchange with the outside. In order to maintain the internal space of the freezer compartment at a low temperature, the urethane foam material having low thermal conductivity is sprayed onto the bottom and / .

In this connection, the urethane foam, specifically the rigid urethane foam, has excellent heat resistance, strength (for example, compressive strength and shear strength), workability, adhesiveness, compatibility, heat stability and water resistance, . A typical construction method of a urethane foam is an insulation construction method in which a spray coating is sprayed directly onto a structure. In particular, spray coating not only allows the formation of a continuous layer of urethane foam on the faces of various geometric shapes, but also minimizes crevices and joints.

Specifically, a spray coating method for forming a urethane foam involves rapid volume expansion (foaming) by mixing a two-component urethane raw material (resin premix (liquid A) and isocyanate (liquid B) The urethane foam is formed, and the temperature is raised to about 120 캜 due to the reaction heat. The resin premix refers to a stock solution containing a mixture of a polyol, a catalyst, a foam stabilizer, and other additives. Urethane foam having a predetermined thickness is formed by foaming (volume expansion) in accordance with the urethane reaction of the reaction raw material. However, cracks are formed in the urethane foam when the reaction heat does not escape to the outside during the process of forming the foam by the foaming reaction by the spray coating.

After the urethane foam insulation is applied, it is cooled to the operating temperature in the freezing warehouse, and the insulation of the applied urethane foam also undergoes shrinkage due to cooling. Specifically, the urethane foam typically has a coefficient of linear expansion of about 6 x 10 < ^-6 > / DEG C, so that it shrinks while being cooled under the operating conditions of the freezing storage. As a result, the heat insulating material of the applied urethane foam shrinks to form a crack. Cracking due to shrinkage occurs throughout the wall, particularly cracking at the corner where the vertical wall and ceiling (or bottom) wall meet. As described above, under the freezing temperature, the urethane foam often fails to overcome the inherent physical property limit compared with the ordinary insulated layer in the warehouse, which causes an increase in crack formation.

In order to alleviate the above-mentioned problem, there has been developed a technique for mitigating crack formation by forming a urethane foam after interposing a mesh structure on a surface (i.e., a wall surface) on which a heat insulating material is formed Korean Patent Nos. 1027618 and 544059, and International Patent Publication No. 2015-0143243).

However, the urethane foam applied to the wall surface of the freezing warehouse must have a significantly higher heat insulating property than that of other buildings in order to provide a good refrigeration effect and energy efficiency. To this end, the urethane foam layer in the refrigeration warehouse needs to be formed to have an increased thickness, for example, up to about 100 mm, and even up to about 500 mm, as compared to other applications. As described above, since the crack formation due to the shrinkage also increases with the increase of the thickness of the urethane foam, it is not effective to form a heat insulating layer of the urethane foam only on the surface where the mesh structure is provided.

Therefore, there is a demand for a construction method capable of effectively suppressing the formation of cracks in a urethane foam, which is a heat insulating material formed on a wall of a freezing warehouse.

In order to prevent the formation of cracks in the urethane foam which is applied to the wall of the freezer warehouse by the spray coating method, the inventors of the present invention have found out that the urethane foam raw material is sprayed by the lattice construction method by pre- (I) providing a mesh structure at a specific location in the thickness direction during the spray coating step by step, and / or (ii) providing a plurality of And a step of introducing a wooden frame.

Accordingly, the present invention provides a construction method capable of suppressing crack formation caused during the process of applying urethane foam on a wall of a freezing warehouse and / or cracking caused by cooling process of the heat insulating material.

According to a first aspect of the present invention,

Forming a heat insulating material by spray coating a urethane foam forming raw material on a wall of a freezing warehouse by a zigzag method with a time difference in a grid pattern,

Further comprising the step of installing a mesh structure at a position corresponding to 65 to 85% of the total thickness of the heat insulating material from the surface of the wall during the process of forming the heat insulating material, and

Wherein a thickness of the heat insulating material is in the range of 150 to 500 mm.

According to a second aspect of the present invention,

Forming a heat insulating material by spray coating a urethane foam forming raw material on a wall of a freezing warehouse by a zigzag method with a time difference in a grid pattern,

Wherein at least two wooden frames are arranged at regular or irregular intervals in the longitudinal direction of the heat insulating material at a predetermined height from the wall surface in the thickness direction of the heat insulating material prior to the spray coating, The frame is buried, and

Wherein a thickness of the heat insulating material is in the range of 150 to 500 mm.

According to an exemplary embodiment, the wooden frame may be arranged so as to be connected to an anchor member which is fixed to the wall surface of the freezing warehouse and extends in the thickness direction of the heat insulating material.

According to an exemplary embodiment of the present invention, a plurality of wooden frames are embedded in the heat insulating material layer along the extending direction of the anchor member. Between the plurality of wooden frames, a boundary line between the spray coating layers adjacent in the thickness direction of the heat insulating material Can be located.

According to a third aspect of the present invention,

Forming a heat insulating material by spray coating a urethane foam forming raw material on a wall of a freezing warehouse by a zigzag method with a time difference in a grid pattern,

Wherein at least two wooden molds are arranged at regular or irregular intervals in the longitudinal direction of the heat insulating material at a height corresponding to 40 to 60% of the heat insulating material from the wall surface prior to the spray coating, The at least two wooden frames are embedded in the frame,

A mesh structure is installed at a position corresponding to 65 to 85% of the total thickness of the heat insulating material from the surface of the wall during the process of forming the heat insulating material,

Wherein a thickness of the heat insulating material is in the range of 150 to 500 mm.

The method of applying urethane foam as a thermal insulator in a freezing warehouse according to the present invention is based on a method of spray coating a urethane foam raw material in a zigzag manner in a lattice pattern with a time difference. In the step spray coating process, Or at least two timber frames are embedded at regular or irregular intervals in the heat insulating material, thereby causing shrinkage occurring in the process of the urethane foam material insulation and shrinkage caused by keeping the inside of the freezing warehouse at a low temperature Cracks can be effectively suppressed.

In particular, since the construction method provided by the present invention can be implemented without substantially changing the structure of the existing refrigeration warehouse, the construction cost for suppressing the crack formation of the heat insulating material can be minimized. Therefore, wide commercialization is expected in the future.

Each of Figs. 1A and 1B is a plan view and an example of an example in which the urethane foam forming raw material is spray coated on the wall of the freezing warehouse in a zigzag manner at a time difference in a lattice pattern, ego;
The present invention relates to a process for spraying a urethane foam-forming raw material on a wall of a freezing warehouse by a zigzag method, (Installation), and Fig.
Each of Figures 3a and 3b is a schematic view of a refrigerator according to another embodiment of the present invention. Figure 3 is a cross-sectional view of a frozen warehouse according to another embodiment of the present invention. ≪ / RTI > is a view showing an example in which four wooden frames are embedded (installed); And
4 is a view illustrating a method of spraying a urethane foam-forming raw material on a wall of a freezing warehouse by spraying a mesh structure and a plurality of wooden frames together in a zigzag manner, (See FIG.

The present invention can be all accomplished by the following description. The following description should be understood to describe preferred embodiments of the present invention, but the present invention is not necessarily limited thereto. It is to be understood that the accompanying drawings are included to provide a further understanding of the invention and are not to be construed as limiting the present invention. The details of the individual components may be properly understood by reference to the following detailed description of the related description.

The terms used in this specification can be defined as follows.

By "freezing warehouse" may mean any building structure capable of achieving refrigeration and / or refrigeration effects for the purpose of preserving freshness or preventing deterioration of the contents (e.g., food and other products).

It is understood that the term "wall" includes both vertical structures forming the height in the freezer compartment and horizontal structures forming the ceiling and the floor, .

"Urethane foam" refers to a reaction product of a di- or polyisocyanate with an isocyanate-reactive hydrogen-containing compound (polyfunctional alcohol (specifically polyol), aminoalcohol and / or polyamine) and a blowing agent The cellulosic foamed product obtained by the method of the present invention. Here, "urethane" may refer to a polymer having a urethane (-NHCOO-) bond, and "foam" may refer to a honeycomb material produced by a polymer reaction (foaming reaction) to generate bubbles. The urethane foam is classified into an open cell and a closed cell depending on the pore type. Depending on mechanical properties, the urethane foam may be divided into a hard urethane foam, a soft urethane foam and a semi-hard urethane foam.

"NCO%" means the weight percentage of NCO contained in the isocyanate compound.

"Isocyanate index" means the amount of isocyanate used relative to the ratio of the number of hydroxyl groups (-OH) present in the polyol component to the number of equivalents of isocyanate (-NCO), ie the theoretical equivalent, in the urethane reactants . Thus, an isocyanate index of less than 100 means that an excess of polyol component is present, while an isocyanate index of more than 100 means that an excess of isocyanate component is present.

"Spray coating" may refer to a process of applying a raw material for polymer formation (urethane forming raw material in the case of urethane) onto the surface of the adherend by spraying through a nozzle.

The "zigzag method" is a method in which, in forming a heat insulating material by laminating urethane foam layers formed by spray coating a urethane foam raw material in a lattice pattern, the boundary of the grid pattern of the underlying urethane foam layer in the thickness direction of the heat insulating material from the wall surface (Or coating) method in which the coating layer is overlaid on the coating layer.

The expression "with a lattice pattern" means that when the adherend faces are divided into arbitrary lattice forms (consisting of a first pattern portion and a second pattern portion which are arranged alternately adjacent to each other without overlapping each other), the urethane foam- To form a urethane foam layer (unit urethane foam layer) having a continuous surface by performing spray coating on the second pattern portion that is not coated with a time difference after spray coating the first surface of the substrate.

When "comprising" includes any element, it is understood that it may include other elements and / or steps, unless the context requires otherwise.

According to the present invention, instead of forming the heat insulating material by spray coating the urethane foam on the wall in the freezing warehouse, the heat of reaction during the foaming reaction of the raw material for forming the urethane foam is insufficient by using the lattice construction method by pre- And the shrinkage of the urethane foam can be alleviated by introducing the mesh structure and / or a plurality of spaced apart wooden frames into the heat insulating material during the stepwise construction process. As a result, it is possible to suppress the formation of cracks during the construction and operation of the urethane foam material in the freezer warehouse. That is, the formation of cracks can be suppressed by a construction method in which the time-dependent characteristics of the urethane foam spray coating method of each step are combined with the additional components for shrinkage relaxation of the urethane foam.

1A and 1B are a plan view and a flowchart showing an example in which the urethane foam-forming raw material is spray-coated on a wall of a freezing warehouse in a zigzag manner at a time difference in a lattice pattern.

In this figure, the heat insulating material provided on the wall of the freezing warehouse is formed of a laminated structure of a plurality of urethane foam layers. For example, a second urethane foam layer (10) formed on the first urethane foam layer 10 ') are stacked on a substrate. Although the first pattern portion 11 and the second pattern portion 12 constituting the grating pattern for convenience are distinguished from each other in order to easily understand the grid pattern, It can be understood that the raw material for forming urethane foam having substantially the same composition is used.

According to the above description, the material for forming urethane foam is first spray-coated on the surface of the wall of the freezing warehouse corresponding to the plurality of first pattern portions 11. Rapid volume expansion (specifically, volume expansion and curing) by the foaming reaction occurs after spray coating and shrinks as the heat of reaction (or bubbles) is discharged. Thereafter, the first urethane foam layer 10 forms a continuous surface through volume expansion and contraction due to the foaming reaction by spray coating on the region corresponding to the second pattern portion 12. At this time, the time interval of spray coating between the first pattern layer 11 and the second pattern layer 12 is, for example, about 5 to 50 minutes (specifically about 10 to 40 minutes, more specifically about 20 to 30 minutes ) Range.

The thickness of the first urethane foam layer 10 can be selected within a range in which the foaming reaction heat can be effectively discharged. When the thickness of the first urethane foam layer 10 is excessively small, However, the time required for forming the heat insulating material may be excessively long. On the other hand, when the thickness of the first urethane foam layer 10 is excessively large, the reaction heat is not sufficiently discharged, which may lead to crack formation. In view of the above, the thickness of the first urethane foam layer 10 can be adjusted, for example, in the range of about 20 to 90 mm, specifically about 30 to 70 mm, more specifically about 40 to 60 mm.

The urethane foam-forming raw material is not particularly limited as long as it is a raw material for forming a urethane foam suitable as a heat insulating material. According to an exemplary embodiment, the raw material for forming the urethane foam is mainly composed of liquid A (resin premix) and liquid B (containing isocyanate).

At this time, the liquid A is typically a polyfunctional alcohol, specifically including a polyol, and a urethane reaction catalyst, a foaming agent, a surfactant (optional), and other additives such as a chain extender, a cell modifier, , ≪ / RTI > Thus, the urethane foam can be formed by reacting the polyol component and the isocyanate component as basic reactants and in the presence of a foaming agent, a reaction catalyst, a surfactant, and other additives.

Polyol component

The polyol component may be an ether polyol, an ester polyol or a mixture thereof. Examples of the ether polyol include glycerine, trimethanolpropane, pentaerythritol, dipentaerythritol, Polyfunctional alcohols such as? -Methylglucoside, xylitol, sorbitol and sucrose; (For example, ethylene oxide, propylene oxide, and the like) with a polyfunctional amine, such as ethylene oxide, propylene oxide and / or ortho-toluene diamine, ethylene diamine, triethanol amine, Oxides, butylene oxides, or mixtures thereof). Examples of ester polyols include reaction products of polyhydric alcohols with polyhydric acids (especially polyhydric carboxylic acids). At this time, an anhydride thereof, an ester compound with a lower alcohol or a mixture thereof may be used instead of the polyvalent acid. More specifically, it is possible to use a polyhydric alcohol such as dicarboxylic acid (e.g., phthalic anhydride, terephthalic acid, suberic acid, sebacic acid, isophthalic acid, trimellitic acid, succinic acid, adipic acid, fumaric acid, , Diethylene glycol, 1,4-butanediol, glycerin, trimethylol propane, propylene glycol, etc.) can be used. Further, a single ester polyol may be used, or two or more ester polyols may be used in combination.

According to the exemplary embodiment, the hydroxyl value of the usable polyol (ether polyol and / or ester polyol) is, for example, about 170 to 500 mg KOH / g to satisfy various physical properties required as a heat insulating material for a refrigeration warehouse, Can be in the range of about 250 to 400 mg KOH / g, more specifically about 300 to 370 mg KOH / g in terms of the desired properties (e.g., thermal conductivity, moisture resistance Mechanical strength (compressive strength, flexural strength, etc.)) can be controlled.

Isocyanate component

The isocyanate components that can be used in the urethane reaction typically include compounds in which isocyanate groups are linked by aromatic, cycloaliphatic and / or aliphatic groups, and these isocyanates may be used alone or in combination. The isocyanate reacts with the polyol component to form a urethane bond in the urethane foam. The isocyanate is an isocyanate compound for producing polyurethane which is known in the art, and examples thereof include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane ( Diisocyanate (hydrogenated MDI, or HMDI), 1,3- and 1,4-diisocyanates (e.g., isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene diisocyanate, dicyclohexylmethane- (TDI), diphenylmethane-2,4'- and / or -4,4'-diisocyanate (MDI), naphthylene-1, 2,4,6-toluene diisocyanate 5-diisocyanate, triphenylmethane-4,4 ', 4 "-triisocyanate, polyphenyl-polymethylene- Modified polyisocyanates, urethane-modified polyisocyanates, urea-modified polyisocyanates, urea-modified polyisocyanates, urethane-modified polyisocyanates, urethane-modified polyisocyanates, , Isocyanurate-modified polyisocyanates, urea-modified polyisocyanates, burette-containing polyisocyanates, isocyanate-terminated prepolymers, or mixtures thereof.

According to an exemplary embodiment, the isocyanate component is a functional group of 2.5 to 3.5, and its molecular weight as MDI, polymeric MDI, etc. having a NCO% of 15 to 35 (M _w) is from about 300 to 450 Lt; / RTI > In particular, p-MDI is brown at room temperature, and its liquid viscosity range can range from about 150 to 400 cps (25 DEG C). Further, considering the physical properties of the urethane foam suitable for the heat insulating material of the insulating warehouse, the isocyanate index may be in the range of, for example, about 80 to 300, specifically about 100 to 250, more specifically about 120 to 180.

blowing agent

The blowing agent serves to generate bubbles during the urethane reaction. The blowing agent is classified into a component that forms vapor bubbles (sublimation) by reaction heat and does not participate in the urethane reaction, and a chemical foaming agent (generates water by reacting with isocyanate) . In the case of the former, the foaming agent component is vaporized (sublimed) due to the generated heat during the foaming reaction, and the resulting gas is accumulated by the cells surrounded by the foam, so that the urethane foam can exhibit a low thermal conductivity. As the foaming agent, hydrocarbon type C-pentane, hydrogenated chloroform fluorocarbon type HCFC-141b, hydrofluorocarbon (HFC) type HFC-245fa, HFC-365mfc, etc. may be used singly or in combination. However, the use of the CFC foaming agent is not excluded, but it may cause environmental problems and it may be preferable to exclude the use as much as possible. Preferably, more environmentally friendly components such as C-pentane, HFC, and the like can be used.

Illustratively, the amount of the blowing agent to be used can be determined according to the required properties of the polyurethane foam to be produced (for example, density, etc.). For example, the amount of the foaming agent is at most about 30 parts by weight based on 100 parts by weight of the polyol, To about 5 to 25 parts by weight, more specifically about 7 to 20 parts by weight.

Alternatively, water can be used as a blowing agent, and it can react with isocyanate to generate carbon dioxide gas. In this case, the amount of water used is about 0.1 to 20 parts by weight, more preferably about 0.1 to 20 parts by weight, May range from about 0.5 to 10 parts by weight.

Urethane reaction catalyst

As a reaction catalyst between a polyol and an isocyanate for forming a urethane foam, for example, a catalyst such as triethylamine, tripropylamine, triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N- N, N, N-diethanolamine, N, N-dimethylethanolamine, diethylenetriamine, N, N-dimethylethanolamine, triethanolamine, N-methyldiethanolamine, N, N ', N'-tetraethylhexamethylenediamine, bis [2- (N (N, N'-tetramethylbutanediamine) N, N ', N', n-pentamethyldiethylenetriamine, triethylenediamine, N, N-dimethylaminoethyl) Formic acid and other salts of triethylenediamine, amino groups and oxyalkylene adducts of primary and secondary amines, and azo compounds such as N, N-dialkylpiperazines , A number of the N, N ', N' '- can be used to trialkyl-amino-alkyl-hexahydro-triazol jinryu of β- aminocarbonyl catalyst such as amine-based catalysts.

The urethane reaction catalyst may be used alone or in combination. The amount of the urethane reaction catalyst may be selected in the range of about 0.5 to 2 parts by weight, specifically about 0.5 to 1 part by weight based on 100 parts by weight of the polyol component.

Surfactants

In some cases, the surfactant can be selectively used in the urethane reaction product, and the reaction stabilization of the reaction raw material, the generation of bubbles and the stabilization of the bubbles can be performed. For example, it is possible to increase the surface area by decreasing the surface tension by decreasing the surface tension, and by increasing the surface elasticity, it is possible to recover the film which expands critically before the cell destruction occurs, thereby improving the stability of the foam .

As described above, the type of the surfactant can be appropriately selected in consideration of the cell structure in the foamed polyurethane. Specific examples thereof include silicone surfactants. For example, a polyalkylene glycol silicone copolymer Can be used. The molecular weight of such a surfactant can range, for example, from about 2000 to 9000 g / mol, more specifically from about 4,000 to 8000 g / mol. The amount of the surfactant to be used may be, for example, about 1 to 4 parts by weight, specifically about 1.5 to 3 parts by weight, based on the weight of the polyol component.

Other ingredients added

Illustratively, optional components such as a crosslinking agent, a chain extender, a cell modifier, a reaction inhibitor, and a flame retardant may be contained in the liquid A singly or in combination.

In the case of a crosslinking agent, the components used for reinforcing the strength of the urethane foam and shortening the curing time include, for example, compounds such as ethylene glycol, propylene glycol, butanediol, glycerol and the like. It is possible. In the case of the chain extender, it is preferable to use a low molecular weight polyhydric alcohol (e.g., ethylene glycol, 1,4-butanediol, glycerin, etc.), a low molecular weight amine polyol (diethanolamine, triethanolamine, Lendiamine, etc.) can be used. In addition, the flame retardant is added to impart heat resistance to the heat insulating material for freezing storage, and it can be used in an appropriate amount in consideration of the level required when necessary. For example, a phosphorus flame retardant (TCPP, TCEP, etc.) can be used.

Urethane foam forming process

According to one embodiment, the liquid A and the liquid B constituting the raw material for forming a urethane foam are separately prepared and mixed in the mixer, and after the mixing, the mixture is rapidly discharged (injected) from the vaporizer and expanded and cured, .

The foaming temperature may be, for example, from about 15 to 45 DEG C (specifically about 20 to 35 DEG C) and the foaming pressure is about 7 to 15 MPa (specifically about < RTI ID = 9 to 12 MPa). Particularly, the nozzle of the blowing machine is in a horizontal state, and the discharge amount can be set to be, for example, about 30 kg / minute or less, specifically about 10 to 25 kg / minute, specifically about 15 to 20 kg / minute. This is low as compared with the case where it is employed in a typical urethane foam forming process. In order to suppress the occurrence of cracks, the reaction heat is effectively discharged during foaming. In this case, the nozzle provided in the foaming machine is, for example, of a cylindrical shape having an inner diameter of, for example, about 12 to 20 mm (specifically about 15 to 18 mm) and a length of about 150 to 320 mm, To 250 mm. In a specific embodiment, the discharge end of the nozzle may be formed so as to be inclined upward.

Referring to FIG. 1B, after the first urethane foam layer 10 is formed in a lattice manner, a first pattern portion 11 'and a second pattern portion 12' are formed thereon in a similar lattice pattern, The second urethane foam layer 10 'may be laminated on the corresponding region. At this time, the second urethane foam layer 10 'may be formed in a lattice pattern covering the boundary line 14 of the grid pattern of the lower first urethane foam layer 10 (i.e., in a zigzag manner in the thickness direction) . This method can maximize the pre-shrinkage effect of each section, and is effective in suppressing the formation of cracks due to the heat of reaction generated in the foaming reaction.

In an exemplary embodiment, the second urethane foam layer 10 'may be formed under the same or different spray coating conditions as the first urethane foam layer 10, and may also be formed with the same or different dimensions (e.g., ). In this regard, although the thickness of the first urethane foam layer 10 and the second urethane foam layer 10 'is shown to be the same in FIG. 1B, alternatively, the thickness of the second urethane foam layer 10' Can be set in the range of about 60 to 95%, specifically about 80 to 90%, of the first urethane foam layer 10. This is because it is possible to provide advantages such as facilitating the installation of the mesh structure at a specific position in the heat insulating material as described later.

As described above, in the present invention, a subsequent urethane foam layer (specifically, a third urethane foam layer, a fourth urethane foam layer, and the like) is formed in the same manner as described above (that is, a zigzag grating pattern) It can be sequentially formed step by step. Again, the third urethane foam layer may have the same thickness as the second urethane foam layer 10 ', or alternatively may be spray coated to have a thinner thickness. At this time, the reduction degree of the thickness can be selected within the above-mentioned ratio range. The fourth urethane foam layer can also be dimensioned in the same manner as in the third urethane foam layer.

As described above, the laminated structure of the urethane foam layers formed in a zigzag fashion forms a heat insulating material that is applied on the wall of the freezing warehouse. In an embodiment of the present invention, the overall thickness of the insulation may be in the range of, for example, about 150 to 500 mm, specifically about 200 to 450 mm, more specifically about 250 to 400 mm.

First embodiment

According to the present invention, as described above, the urethane foam is formed in a staggered manner with a time difference, and an additional crack formation inhibiting element is introduced in the process of installing the heat insulating material.

According to one embodiment of the present invention, the mesh structure is embedded (introduced) into the heat insulating material at a certain distance from the surface of the heat insulating material (surface opposite to (opposite to) the surface of the heat insulating material in contact with the wall). Particularly, it should be noted that if a temperature difference (specifically, an initial temperature difference) is induced in the cooling process by the operation temperature of the freezing warehouse by disposing the mesh structure at a relatively close position from the surface of the heat insulating material, Crack formation can be suppressed.

In this regard, FIG. 2 shows an example in which the mesh structure 21 is introduced at a specific thickness position in the insulation material based on the step-by-step spray coating method shown in FIGS. 1A and 1B described above for the urethane foam-forming raw material.

As described above, the mesh structure 21 can be installed on the laminated structure before the entire heat insulating material 20 is formed by using a method in which the insulating material of the urethane foam is not formed at one time but is formed in a time- .

2, a first urethane foam layer 10, a second urethane foam layer 10 'and a third urethane foam layer 10 "are sequentially formed on a wall of a freezing storage, and then a mesh structure 21 And a fourth urethane foam layer 10 '' 'is formed in a lattice pattern on the second urethane foam layer 10' '' to form a heat insulating material. In the figure, three urethane The number of the urethane foam layers is not limited thereto. In some cases, the urethane foam layers may include two urethane foam layers on the lower side of the mesh structure 21, or alternatively, It may also comprise four or more urethane foam layers.

According to this embodiment, a thickness direction position corresponding to about 65 to 85%, specifically about 70 to 80%, more specifically about 72 to 78% of the total insulation thickness from the wall surface (or the contact surface of the wall and the insulation) The mesh structure 21 can be provided. In this way, embedding the mesh structure 21 at a specific location in the heat insulating material 20 provides a significant technical advantage, such that the mesh structure is buried in the central region (approximately 50% of the location) in the heat insulating material 20 The crack formation due to the shrinkage due to the cooling in the freezing storage can be significantly suppressed.

In this connection, when the mesh structure 21 is located at a position that is excessively adjacent to the surface of the heat insulating material 20 (for example, when it is installed at a position corresponding to about 95% from the wall surface) It is difficult to achieve the effect of suppressing crack formation across the entire heat insulating material by providing only the mitigating effect. On the other hand, when the heat insulating material 20 (for example, in a position corresponding to about 40% from the wall surface) ) Cracks on the surface can be increased. Therefore, it may be advantageous to provide the mesh structure 21 in the above-mentioned positional interval in the heat insulating material 20. [

According to an exemplary embodiment, the mesh structure 21 may be made of a plastic material, a metal material (e.g., stainless steel), a glass fiber material, or the like. At this time, the mesh size (or diameter) of the mesh structure 21 is determined considering the factors affecting shrinkage and crack formation such as the material of the mesh structure, the thermal properties of the urethane foam, the dimensions (for example, And can be selected in an appropriate range. The diameter of the strands constituting the mesh structure 21 may be, for example, in the range of about 5 to 2000 m, specifically about 10 to 1000 m, but it may be varied depending on the material of the mesh structure 21, But the present invention is not limited thereto.

According to an exemplary embodiment, the mesh structure 21 can be made of a glass fiber material, and the molten glass can be formed, for example, in a range of about 10 to 300 mu m, specifically about 20 to 100 mu m, 80 < RTI ID = 0.0 > um, < / RTI > and can be used to form a mesh structure. In the case of such a glass fiber material mesh structure, since the heat insulating property is excellent, it is possible to enhance the adiabatic effect as compared with other materials when introduced into the heat insulating material for the freezing storage, and it has good mechanical strength and chemical durability, It is possible to provide an advantage that it is less influenced by the user.

After the introduction of the mesh structure 21 as described above, one or more urethane foam layers, such as a fourth urethane foam layer 10 '' ', may be applied in the manner previously described (i.e., in a zig- ). ≪ / RTI >

Second Embodiment

According to another embodiment of the present invention, at least two timber frames are provided at regular or irregular intervals in the longitudinal direction of the heat insulating material at a predetermined height on the basis of the thickness direction of the heat insulating material from the wall surface of the freezing storage before spray coating of the urethane foam- The crack formation can be suppressed. In this connection, each of Figs. 3A and 3B shows an example in which at least two wooden frames spaced apart from each other are embedded (installed) in a heat insulating material made of a urethane foam material.

Referring to FIG. 3A, a wall constituting a horizontally extending ceiling surface in a freezing warehouse is formed by joining a vertically elongated wall to form a corner, and a heat insulating material 30 made of a urethane foam material having a predetermined thickness forms a corner portion And is formed on the wall. At this time, a plurality of wooden frames 31 are arranged at predetermined intervals (regular or irregular intervals) in the heat insulating material. As described above, the plurality of wooden frames 31 embedded in the thermal insulation material induce the shrinkage phenomenon of the urethane foam, which is generated due to cooling under the operating conditions of the freezing warehouse, to disappear in the middle without affecting the entire heat insulating material, Crack formation can be effectively suppressed.

3A, the plurality of wooden frames 31 are fixed to the surface of the wall of the freezing warehouse, and anchor members 32 extending in the thickness direction of the heat insulating material 30, specifically, anchor members 32, A wooden frame 31 is connected to the front end of the frame 31. [ The anchor member 32 is not limited to a particular shape or material, but is typically made of a metal material (e.g., iron or an alloy thereof) so long as the wooden frame 31 can be fixed at a predetermined position in the heat insulating material. And may be a linear or rod-shaped fixed (supporting) structure made of a plastic material (e.g., polypropylene) or the like.

Illustratively, the diameter of the anchor member 32 is not particularly limited as long as it can sufficiently support the wood frame 32 in the process of forming the urethane foam, but may be, for example, about 0.1 to 5 mm, specifically about 0.5 To about 3 mm, and more specifically from about 1 to about 2 mm. In addition, the anchor member and the wooden frame 31 can be connected in various ways such as an interference fit type, a screw connection type, and a circumferential bundle type.

In the above embodiment, after the wooden frame 31 is connected to and fixed (supported) by the anchor member, by forming the urethane foam layer in the grid pattern of zigzag pattern by spray coating with a time difference as described above, The mold 31 can be embedded in the heat insulating material.

The plurality of wooden frames 31 may have a hexahedral shape, but the present invention is not limited thereto, and various shapes such as spherical shapes are also possible. In the illustrated example, the width and length of the wooden frame 31 can be selected in the range of about 20 to 60 mm (specifically about 30 to 50 mm, more specifically about 40 to 45 mm), respectively. According to a specific embodiment, the material of the wooden frame 31 may be, for example, chrysanthemum, mulberry, duck, ash, maple, chestnut, elm, walnut or birch. More specifically, it is possible to use an untransferable sheet. Since the untransformed sheet is softwood as a kind of conifer, when it is embedded in a heat insulating material of a urethane foam, the shrinkage of the urethane foam due to cooling can be effectively absorbed and eliminated, And thus can be preferably used in this embodiment.

Further, the distance between the plurality of wooden frames 31 may be in the range of, for example, about 5 to 100 cm, specifically about 10 to 50 cm, and more specifically about 15 to 30 cm, The size of the wall in the warehouse, the operating temperature, and the like.

3B shows another example of the present embodiment. In this embodiment, a plurality of wooden frames are connected to each of the plurality of anchor members 32 spaced apart from each other in the heat insulating material. In particular, the individual anchor members 32 The two wooden frames 31 'and 31 "are connected at a certain distance.

According to an illustrative embodiment, a first wood frame 31 'in a second urethane foam layer 10' and a second wood frame 31 'in a third urethane foam layer 10 " in combination with a stepwise lamination of urethane foams It is possible to embed the wooden frames 31 'and 31 "in the heat insulating material in such a manner as to locate the frame 31 ". When the wooden frame is introduced into each of the adjacent urethane foam layers in the heat insulating material having the laminated structure (In particular, when a wood frame is introduced into the urethane foam layer near the surface of the heat insulating material), the shrinkage removing effect is high at the surface of the heat insulating material which is exposed to the direct cooling process and is likely to be cracked, or in the vicinity of the heat insulating material adjacent thereto. , The distance between the two wooden molds 31 'and 31' 'can be appropriately adjusted according to the thickness of the urethane foam layer into which the respective wooden molds are introduced.

Third Embodiment

According to another embodiment of the present invention, the above-described step-by-step spray coating method can be used to include all of the two crack-inhibiting elements described above in a single thermal insulation material 40. [ In this regard, Fig. 4 shows an example in which a mesh structure and a wood frame are introduced together while spraying the urethane foam-forming raw material on the wall of the freezing depot.

In the illustrated embodiment, the wooden frame 41 is located in a central region (e.g., a position corresponding to about 40 to 60%) on the basis of the thickness of the heat insulating material 40, (For example, a position corresponding to about 65 to 85%) near the surface of the heat insulating material 40 by the heat insulating material 42. For this purpose, for example, a wooden frame 41 may be embedded in a second urethane foam layer 10 'and a mesh structure 51 may be formed between the second urethane foam layer 10' and the third urethane foam layer 10 ' "). ≪ / RTI >

The present invention can be more clearly understood by the following examples, and the following examples are merely illustrative of the present invention and are not intended to limit the scope of the invention.

Example 1

As shown in Table 1 below, liquids A and B were prepared, respectively.

ingredient Amount used (parts by weight) A sum Polyol (polypropylene glycol; hydroxyl value: 350 KOH / g) 100 Blowing agent (HCFC-141b) 15 Amine-based catalysts (pentamethyldiethylenetriamine and triethylenediamine) 0.9 Surfactant (B8465) 1.5 Flame retardant (tris (2-chloropropyl) phosphate 5 Other additives 8 B solution p-MDI (NCO%: 32%; viscosity: 250 cps) 135

As shown in FIG. 1A, the two pattern portions (the first pattern portion and the second pattern portion) as shown in FIG. 1A were prepared by using a concrete plate material (100 cm x 200 cm) Pattern part). Thereafter, the liquid A and the liquid B were introduced into the mixing head, mixed at about 35 ° C, and sprayed to a region corresponding to the first pattern portion of the concrete plate surface using a spray gun equipped with a spray nozzle. At this time, the discharge pressure was set to 12 MPa and the discharge amount was set to 27 kg / min. Thereafter, the heat generated in the foaming process was waited until sufficient heat was released.

Then, a urethane foam-forming raw material was sprayed to a region corresponding to the second pattern portion on the concrete plate surface to form a urethane foam.

The thickness of the urethane foam layer (first urethane foam layer) spray-coated in a lattice pattern manner with a time difference as described above was about 45 mm.

Thereafter, a second urethane foam layer was formed on the first urethane foam layer in the same manner, and the second urethane foam layer was formed so as to overlap the boundary line between the first pattern portion and the second pattern portion of the first urethane foam layer so as to be laminated in a zigzag manner in the thickness direction Spray coating was carried out and, in the same manner, a third urethane foam layer was formed in a zigzag manner on the second urethane foam layer.

Subsequently, a mesh structure having a strand diameter of 500 탆 was placed on the third urethane foam layer, and then a fourth urethane foam layer was formed in a staggered manner to complete the process of forming the insulating material (total thickness of the insulating material: about 181 mm ).

As a result, the mesh structure was located at a position corresponding to about 73% of the total thickness of the heat insulating material from the surface of the concrete plate. As a result of performing visual observation on the thus formed heat insulating material, cracks were hardly found on the surface of the heat insulating material.

The physical properties and thermal insulation performance of the insulation were evaluated according to KS M 3809, and the results are shown in Table 2 below.

Properties Measures Remarks Foam density (kg / m3) 33 KSM 3809 Thermal conductivity (W / mK) 0.020 Compressive strength (N / cm2) 12 Water absorption rate (g / 100 cm 2) 2.1 Independent air bubble rate 92.3% ASTM D-2856 Flammability Flame retardant grade 3 KSF 2271

As shown in the above table, the heat insulating material sprayed with the urethane foam raw material in a lattice pattern zigzag manner satisfies the specification relating to the heat insulating material of the urethane foam material as in the present embodiment, and the heat insulating performance and the mechanical properties . ≪ / RTI >

In order to confirm the degree of crack formation due to cooling at the freezing temperature, the heat insulating material formed on the concrete plate was allowed to stand for about 96 hours in a freezing warehouse maintained at -35 ° C, and the degree of crack formation was visually observed. As a result, it was confirmed that the formation of cracks was insignificant in the heat insulating material as compared with before the freezing test.

Example 2

A heat insulating material having a laminated structure of first to fourth urethane foam layers was prepared by using the same urethane foam forming raw material as in Example 1. [ However, in this embodiment, 10 anchors (diameter: 1 mm) made of ten ferroalloys are arranged at intervals of 15 cm on the surface of the concrete plate, and a wood frame (45 mm x 45 mm) And then spray-coated to form an insulating material. Finally, the untreated wood frame was embedded in the intermediate region based on the thickness of the heat insulating material.

Further, as a result of observing the tendency of crack formation at low temperature in the same manner as in Example 1, the degree of crack formation was insignificant in the heat insulating material before and after freezing. This is probably because the untreated wood frame embedded in the insulation effectively absorbed the shrinkage caused by the temperature difference during the cooling process.

Example 3

In this embodiment, the same urethane foam-forming raw material as in Examples 1 and 2 was used to apply a heat insulating material having substantially the same dimension on a concrete plate material, but simultaneously provided with the shrinkage removing elements introduced in Examples 1 and 2 .

First, 10 anchors (diameter: 1 mm) made of ferroalloys were arranged at intervals of 15 cm on the concrete plate surface, and a wood frame (45 mm x 45 mm) was fastened to the tip of the anchor Spray coating is carried out in a zigzag manner in accordance with the time difference so that the untreated wood frame is located in a region located at about 50% of the total thickness of the heat insulating material, and between the third urethane foam layer and the fourth urethane foam layer during the subsequent spray coating process Mesh structure.

As a result of the production of the heat insulating material as described above, crack formation in the heat insulating material applied on the concrete plate material was not found, and as a result of performing a freezing test on the heat insulating material formed on the concrete plate material, Were substantially not found.

Comparative Example 1

Using the same urethane foam-forming raw material as in Example 1, a heat insulating material made of urethane foam material having a thickness of about 180 mm was applied on the concrete surface. As a result of visually observing the applied heat insulation material, it was confirmed that a considerable number of cracks were formed.

Subsequently, the tendency of crack formation at the low temperature with respect to the heat insulator was observed, and it was remarkably increased in the formation frequency as well as the crack size as compared with Example 1. In particular, it was confirmed that the number of cracks increased by about 50% or more as compared with Example 1.

According to the above-mentioned experimental results, when the urethane foam raw material is spray coated by a grid pattern zigzag method with a time difference as in the embodiment, the heat generated during the foaming (or foaming / curing) The shrinkage phenomenon due to the urethane reaction was suppressed. Further, the shrinkage action according to the temperature gradient applied to the insulating material at the freezing operation temperature is absorbed by the mesh structure (Example 1), the wooden frame (Example 2), or the combination of the mesh structure and the wooden frame (Example 3) Cracks due to the cracks can be effectively suppressed. Particularly, it is preferable in view of workability that a mesh structure and / or a wood frame, which is a crack formation inhibiting element, can be introduced into a heat insulating material by a stepwise lamination method in a refrigeration experiment.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

10: first urethane foam layer 10 ': second urethane foam layer
10 ": third urethane foam layer 10 ''': fourth urethane foam layer
11, 11 ', 11 ": first pattern portion 12, 12', 12"
20, 30, 40: insulation material 21, 51: mesh structure
31, 41: Timber frame 31 ': First timber frame
31 ": second wooden frame 32, 42: anchor member

Claims (5)

Forming a heat insulating material having a thickness of 150 to 500 mm by spray coating a urethane foam forming raw material at a discharging amount of 10 to 25 kg / minute by a zigzag method with a time difference in a grid pattern on a wall of a freezing warehouse,
At least two wooden frames are arranged with a regular or irregular spacing in the range of 5 to 100 cm in the longitudinal direction of the insulation from the wall surface at a height corresponding to 40 to 60% Wherein said at least two wooden frames are embedded in a heat insulating material formed by spray coating,
Wherein each of the at least two wooden frames is arranged so as to be connected to an anchor member fixed to the wall surface of the freezing warehouse and extending in the thickness direction of the heat insulating material,
The boundary between the spray coating layers adjacent to each other in the thickness direction of the heat insulating material is located between the plurality of wooden frames,
A mesh structure having a strand diameter of 5 to 2000 탆 is provided at a position corresponding to 65 to 85% of the total thickness of the heat insulating material from the surface of the wall during the process of forming the heat insulating material,
At least two wooden frames arranged in the longitudinal direction of the heat insulating material and a plurality of wooden frames connected to each other along the extending direction of the anchor member have a hexahedron shape and the width and length thereof are in the range of 20 to 60 mm A method for constructing a heat insulating material made of a urethane foam material. The method of claim 1, wherein spray coating the urethane foam forming material is performed using a foamer equipped with a cylindrical nozzle having an inner diameter of 12 to 20 mm and a length of 150 to 320 mm, Is formed to be inclined toward the upper direction. The method according to claim 1, wherein the diameter of the anchor member is in the range of 0.1 to 5 mm, and the wooden frame is a non-conveying material. The method according to claim 1, wherein the hydroxyl value of the polyol in the urethane foam-forming raw material ranges from 300 to 370 mg KOH / g. delete

Images