Refrigerator

Abstract

This refrigerator comprises: an inner case for forming storage chambers; an outer case on the outside the inner case; a main body including an insulating material between the inner case and the outer case; and doors for opening / closing the storage chambers, wherein the main body includes: the inner case; the outer case disposed outside the inner case; and the insulating material disposed between the inner case and the outer case. The insulating material includes hard polyurethane foam, and the hard polyurethane foam includes: fine particles, each having a surface layer including a hydrophobic group and a hydrophilic group; and urethane resin containing a polyol-derived structural unit and an isocyanate-derived structural unit.

Description

refrigerator

[0001] The present invention relates to a refrigerator comprising a rigid polyurethane foam that can be used as an insulating material for home appliances, such as refrigerators.

[0002] In rigid polyurethane foam, if the bubbles become too large, the thermal conductivity increases, so in order to keep the thermal conductivity small, it is necessary to suppress excessive bubble growth.

[0003] Therefore, in order to make the rigid polyurethane foam have a lower thermal conductivity, it is thought that hollow fine particles made of aluminosilicate or hollow fine particles made of hydrophobic silica are included in the rigid polyurethane foam, as described in patent documents 1 or 2, and that these fine particles physically suppress the growth of bubbles when the rigid polyurethane foam is foamed.

[0004] [Prior Art Literature]

[0005] [Patent Document]

[0006] Patent Document 1: Japanese Patent Laid-Open Publication No. 2021-102664

[0007] Patent Document 2: Japanese Patent Laid-Open No. 2016-194034

[0008] In order to achieve the effect of reducing thermal conductivity in the rigid polyurethane foam described in Patent Documents 1 or 2, it is necessary to increase the content of fine particles to a relatively high level of at least 3 wt% or more.

[0009] However, as examined by the present inventors, when manufacturing a rigid polyurethane foam using hollow fine particles made of aluminosilicate as described in Patent Document 1, if an amount of fine particles to exhibit the aforementioned effect is included in a polyol premix, which is a material for the rigid polyurethane foam, the fine particles themselves are hydrophilic, so that after mixing for some time, a hydrophobic component (e.g., cyclopentane contained in the polyol premix as a blowing agent) that was dissolved or dispersed in the polyol premix is ​​separated, resulting in a problem in that the foaming rate of the rigid polyurethane foam is reduced.

[0010] In addition, even in the case where a rigid polyurethane foam is to be manufactured using hydrophobic fine particles as described in Patent Document 2, it was found that in order to contain the amount of hydrophobic fine particles necessary to exhibit the aforementioned effect in the polyol premix, which is a material for the rigid polyurethane foam, in this case as well, the fine particles separate from the polyol premix after mixing for a period of time, making it difficult to uniformly disperse the fine particles, and as a result, it is impossible to efficiently suppress the growth of bubbles.

[0011] The present invention has been made in consideration of these problems, and its main purpose is to provide a refrigerator including a rigid polyurethane foam having lower thermal conductivity than conventional foam while maintaining a sufficient foaming ratio.

[0012] That is, the rigid polyurethane foam according to the present invention is as follows.

[0013] According to an embodiment, a main body forming a storage room;

[0014] trauma on the outside of the above inner surface; and

[0015] A main body including an insulating material between the inner and outer surfaces; and

[0016] It includes a door configured to open and close the storage room,

[0017] The above insulation material comprises rigid polyurethane foam,

[0018] The above rigid polyurethane foam

[0019] Fine particles each comprising a surface layer including a hydrophobic group and a hydrophilic group; and

[0020] A refrigerator is provided comprising a urethane resin containing a constituting unit derived from polyol and a constituting unit derived from isocyanate.

[0021] According to another embodiment, the surface layer includes a modifying group chemically bonded to the surface of the fine particles,

[0022] The above-mentioned modifier is derived from a surface treating agent and may include a hydrophobic group and a hydrophilic group.

[0023] In another embodiment, the hydrophilic group may be an amino group or a hydroxyl group.

[0024] According to another embodiment, the above group may be a straight-chain alkyl group having 1 to 10 carbon atoms.

[0025] In another embodiment, the hydrophilic group may be between the hydrophobic group and the urethane resin.

[0026] In another embodiment, the above group may further include an aryl group having 4 to 10 carbon atoms.

[0027] In another embodiment, the microparticles may include an inorganic material.

[0028] In another embodiment, the microparticles may be hollow particles or porous particles.

[0029] In another embodiment, the surface treatment agent and the fine particles may include silicone.

[0030] According to another embodiment, the microparticles include a core, a shell on the core, and a surface layer on the shell,

[0031] The density of the core may be lower than the density of the shell.

[0032] According to another embodiment, the rigid polyurethane foam includes a backbone comprising a urethane resin, and includes a plurality of pores defined by the backbone, wherein the microparticles are arranged within the backbone, and each microparticle can be spaced apart from the pores in the urethane resin at least.

[0033] According to another embodiment, the microparticles may be fixed inside the skeleton through chemical bonding with the urethane resin.

[0034] In another embodiment, the chemical bond may include a urea group, a urethane group, or a combination thereof.

[0035] According to another embodiment, the content of the above fine particles in the entire rigid polyurethane foam may be 0.01% by volume or more and 0.5% by volume or less.

[0036] According to another embodiment, the content of the fine particles relative to the entire rigid polyurethane foam may be 0.1 wt% or more and 1.5 wt% or less.

[0037] According to another embodiment, the average particle diameter of the fine particles may be 0.03 μm or more and 20 μm or less.

[0038] In another embodiment, the apparent density of the fine particles is 200 kg / m 3 It could be as follows:

[0039] According to another embodiment, the rigid polyurethane foam may further include a blowing agent comprising an organic compound.

[0040] According to another embodiment, the storage room may further include a cold air supply device configured to supply cold air.

[0041] According to another embodiment, the refrigerator may further include a machine room accommodating at least some of the components belonging to the refrigeration supply device and one or more processors controlling the refrigerator.

[0042] According to the present invention, a refrigerator can be provided in which the thermal conductivity of rigid polyurethane foam is further reduced compared to conventional ones.

[0043] FIG. 1 is a perspective view of a refrigerator according to one embodiment of the present disclosure.

[0044] FIG. 2 is a front view showing the interior of a refrigerator according to one embodiment of the present disclosure.

[0045] Figure 3 is a schematic diagram showing the structure of fine particles contained in a rigid polyurethane foam according to one embodiment of the present invention.

[0046] Fig. 4 is a schematic diagram showing a specific example of a modifier forming a surface layer of fine particles contained in a rigid polyurethane foam according to the present embodiment.

[0047] Fig. 5 is a schematic diagram showing the appearance of suppression of bubble growth of rigid polyurethane foam according to the present embodiment.

[0048] Fig. 6 is a schematic diagram showing the flow of heat in a rigid polyurethane foam according to the present embodiment and a conventional rigid polyurethane foam.

[0049] Figure 7 is a microscopic photograph of a rigid polyurethane foam according to an embodiment and a comparative example of the present invention.

[0050] Figure 8 is a graph showing the relationship between the content of fine particles and thermal conductivity of rigid polyurethane foam according to examples and comparative examples of the present invention.

[0051] It should be understood that the various implementations of the present disclosure and the terminology used therein are not intended to limit the technical features described in the present disclosure to specific implementations, but rather to encompass various modifications, equivalents, or alternatives of the implementations.

[0052] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0053] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0054] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0055] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0056] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0057] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0058] Terms such as "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0059] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0060] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0061] In this disclosure, the “size” of a particle refers to the “particle diameter” of the particle unless otherwise defined.

[0062] In the present disclosure, the "particle diameter" of a particle refers to the average diameter when the particle is spherical, and refers to the average major axis length when the particle is non-spherical. The particle diameter of a particle can be measured using a particle size analyzer (PSA). The "particle diameter" of a particle is, for example, the "average particle diameter." The "average particle diameter" is, unless explicitly stated otherwise, the median particle diameter (D50). The median particle diameter (D50) is the size of the particle corresponding to the 50% cumulative value calculated from the particle side having the smallest particle size in a cumulative distribution curve of particle sizes in which particles are accumulated in order of particle size from the smallest particle to the largest particle. The cumulative value can be, for example, the cumulative volume. The median particle diameter (D50) can be measured, for example, by laser diffraction. Alternatively, the "average particle diameter" can be measured manually or by software from a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image.

[0063] In the present disclosure, a "hydrophilic group" is a functional group that is attracted to water and has a tendency to dissolve in water. Examples of hydrophilic groups include hydroxyl groups, carboxyl groups, amino groups, and the like.

[0064] In the present disclosure, a "hydrophobic group" is a functional group that is not attracted to water and tends not to dissolve in water. Hydrophobic groups include, for example, alkyl groups, aryl groups, and the like.

[0065] In the present disclosure, a “refrigerator” is a home appliance that supplies cold air generated by a compressor of a cold air supply device to a storage room to keep various foods fresh for a long period of time.

[0066] A refrigerator may include, for example, a main body, and the main body may include an inner case, an outer case disposed on the outside of the inner case, and an insulating material provided between the inner case and the outer case.

[0067] In the present disclosure, the "inner case" refers to a component forming a storage compartment. The inner case may include, for example, a case, a plate, a panel, or a liner. The inner case may be formed as a single body, or may be formed by assembling a plurality of plates.

[0068] In the present disclosure, the "outer case" refers to a member forming the outer appearance of the main body. The outer case may be joined to the outer side of the inner case so that an insulating material is placed between the inner case and the outer case.

[0069] In the present disclosure, "insulating material" refers to a material that blocks or inhibits heat transfer. The insulating material may, for example, insulate the interior and exterior of a storage room so that the temperature inside the storage room can be maintained at a set temperature without being affected by the external environment of the storage room. The insulating material may include, for example, foamed insulating material. For example, the foamed insulating material may be placed by fixing the inner and outer layers using a jig or the like, and then injecting and foaming urethane foam, a mixture of urethane resin and a foaming agent, between the inner and outer layers.

[0070] The insulation may further include, for example, a vacuum insulation material in addition to the foam insulation material. For example, the insulation material may consist solely of the vacuum insulation material instead of the foam insulation material. The vacuum insulation material may, for example, include a core material and an outer shell material that accommodates the core material and seals the interior under a vacuum or near-vacuum pressure. The vacuum insulation material may further include an adsorbent that absorbs gases and moisture to maintain a stable vacuum state. The insulation material is not limited to the foam insulation material and / or vacuum insulation material described above, and any material used as an insulation material in the art may be used.

[0071] In the present disclosure, a "storage compartment" refers to a space within a refrigerator for storing items. The storage compartment may include, for example, a space defined by an inner box. The storage compartment may further include, for example, an inner box defining a space corresponding to the storage compartment. The storage compartment may store various items, such as food, medicine, and cosmetics, and may be configured such that at least one side is open for inserting and removing items.

[0072] A refrigerator may, for example, include one or more storage compartments. When a refrigerator has two or more storage compartments, each compartment may have a different purpose and be maintained at different temperatures. To achieve this, each storage compartment may be separated from the others by a partition wall containing insulation.

[0073] Storage rooms may be designed to maintain appropriate temperature ranges, for example, depending on their intended use, and may include "refrigerators," "freezers," and / or "variable temperature rooms," which are distinguished by their intended use and / or temperature range. Refrigerators may be maintained at temperatures appropriate for refrigerated storage, for example. Freezers may be maintained at temperatures appropriate for frozen storage, for example.

[0074] As used herein, "refrigeration" means cooling an item to a temperature that does not freeze. For example, a refrigerator may be maintained at a temperature ranging from 0 degrees Celsius to +7 degrees Celsius.

[0075] As used herein, "freezing" means cooling an item to keep it frozen or in a frozen state. For example, a freezer may be maintained at a temperature ranging from -20 degrees Celsius to -1 degree Celsius.

[0076] The variable temperature room can be used as either a refrigerator or a freezer, with or without the user's choice.

[0077] Storage rooms may be referred to by various names, including "refrigerator," "freezer," and "variable temperature room," as well as "vegetable room," "fresh room," "cooling room," and "ice room." The terms "refrigerator," "freezer," and "variable temperature room" used hereinafter should be understood to encompass storage rooms with corresponding uses and temperature ranges.

[0078] The refrigerator may include at least one door configured to open and close an open side of the storage compartment.

[0079] In the present disclosure, a "door" is a member provided to open and close one or more storage compartments, or a single door provided to open and close multiple storage compartments. The door may be installed on the front of the main body in a rotational or sliding manner.

[0080] The door may be configured to seal the storage compartment when the door is closed, for example. The door may include insulation, similar to the body, to insulate the storage compartment when the door is closed, for example.

[0081] The door may include, for example, a door outer panel forming the front of the door, a door inner panel forming the back of the door and facing the storage compartment, an upper cap, a lower cap, and door insulation provided inside these.

[0082] The door inner panel may be provided with a gasket, for example, that seals the storage compartment by pressing against the front of the body when the door is closed. The door inner panel may include a dyke that protrudes rearward to accommodate a door basket for storing items, for example.

[0083] A door may include, for example, a door body and a front panel detachably connected to the front side of the door body and forming the front of the door. The door body may include, for example, a door outer panel forming the front of the door body, a door inner panel forming the rear of the door body and facing the storage compartment, an upper cap, a lower cap, and door insulation provided inside these.

[0084] Refrigerators can be classified into French door type, side-by-side type, bottom mounted freezer (BMF), top mounted freezer (TMF), or single-door refrigerators, for example, depending on the arrangement of the door and storage compartment.

[0085] The refrigerator may include a cold air supply device arranged to supply cold air to the storage compartment.

[0086] In this disclosure, “refrigeration supply device” means a machine, mechanism, electronic device and / or a system combining these that can generate cold air and guide the cold air to cool a storage room.

[0087] A refrigeration supply device can generate cold air through a refrigeration cycle that includes the processes of compression, condensation, expansion, and evaporation of a refrigerant. To this end, the refrigeration supply device can include a compressor, a condenser, an expansion device, and an evaporator capable of driving the refrigeration cycle.

[0088] The refrigerator may include a mechanical room in which at least some components belonging to the refrigeration supply unit are arranged.

[0089] In this disclosure, the term "machine room" refers to a space where at least some components belonging to a refrigeration supply device are placed. To prevent heat generated by components placed in the machine room from being transferred to the storage room, the machine room may be provided with partitions and insulation. To dissipate heat from components placed within the machine room, the interior of the machine room may be configured to be connected to the exterior of the main body.

[0090] The refrigerator may further include a dispenser provided on the door to provide water and / or ice. The dispenser may be provided on the door so that it is accessible to the user without having to open the door.

[0091] A refrigerator may include an ice-making device configured to produce ice. The ice-making device may include an ice-making tray that stores water, an ice-separating device that separates ice from the ice-making tray, and an ice bucket that stores ice produced in the ice-making tray.

[0092] The refrigerator may include a processor for controlling the refrigerator.

[0093] In this disclosure, a "processor" controls the overall operation of the refrigerator. A processor refers to a hardware device (chip) that includes an integrated circuit (IC) in which electrical circuits are integrated. The processor can control components of the refrigerator by executing a program stored in memory. The processor may include a separate NPU that performs the operation of an artificial intelligence model. The processor may also include a central processing unit (CPU), a graphics processor (GPU), and the like. The processor may generate control signals for controlling the operation of the cold air supply unit. For example, the processor may receive temperature information of a storage compartment from a temperature sensor and generate a cooling control signal for controlling the operation of the cold air supply unit based on the temperature information of the storage compartment.

[0094] Additionally, the processor may process user input of the user interface and control the operation of the user interface based on programs and / or data stored / stored in the memory. The user interface may be provided using an input interface and an output interface. The processor may receive user input from the user interface. Additionally, the processor may transmit display control signals and image data to the user interface for displaying an image on the user interface in response to the user input.

[0095] In this disclosure, "memory" stores or records various information, data, commands, programs, etc. required for the operation of the refrigerator. Memory refers to a hardware device (chip) that includes an integrated circuit in which electrical circuits are integrated. The memory can store temporary data generated during the generation of control signals for controlling components included in the refrigerator. The memory may include at least one of volatile memory and non-volatile memory, or a combination thereof. The processor and memory may be provided integrally or separately. The processor may include one or more processors. For example, the processor may include a main processor and at least one sub-processor. The memory may include one or more memories.

[0096] For example, a refrigerator may include a processor and memory that control all components within the refrigerator, and may also include multiple processors and multiple memories that individually control the components within the refrigerator. For example, the refrigerator may include a processor and memory that control the operation of a cooling device based on the output of a temperature sensor. The refrigerator may also include a separate processor and memory that control the operation of a user interface based on user input.

[0097] In the present disclosure, a “control unit” means a part including a memory that stores or memorizes a program and / or data for controlling a refrigerator, and a processor that outputs a control signal for controlling a cold air supply device, etc. according to the program and / or data memorized in the memory.

[0098] The communication module can communicate with external devices, such as servers, mobile devices, and other home appliances, via a nearby access point (AP). The AP can connect the local area network (LAN) to which the refrigerator or user device is connected to the wide area network (WAN) to which the server is connected. The refrigerator or user device can then connect to the server via the WAN.

[0099] The input interface may include keys, a touchscreen, a microphone, etc. The input interface may receive user input and transmit it to the processor.

[0100] The output interface may include a display, a speaker, and the like. The output interface may output various notifications, messages, information, etc. generated by the processor. An embodiment of the present invention will be described in detail below with reference to the drawings.

[0101] Fig. 1 is a perspective view of a refrigerator according to one embodiment of the present disclosure. Fig. 2 is a front view showing the interior of a refrigerator according to one embodiment of the present disclosure.

[0102] Referring to FIGS. 1 and 2, another embodiment of the present disclosure includes a refrigerator (1000) having a main body (1) having a storage compartment (2, 2a, 2b) and a door (3, 3a, 3b, 3c, 3d) coupled to the main body (1) to open and close the storage compartment.

[0103] The main body (1) of the refrigerator (100) may include an inner case; an outer case disposed outside the inner case; and an insulating material disposed between the inner cases. Since the main body (1) includes the insulating material, the temperature inside the storage compartment (2) can be maintained at a set appropriate temperature without being affected by the environment outside the storage compartment. The refrigerator (1000) includes doors (3, 3a, 3b, 3c, 3d) configured to open and close an open side of the storage compartment (2). Although the refrigerator (1000) is illustrated with four doors (3), the number of doors (3) is not limited thereto, and the upper door (3a) and the lower door (3b) on the right side of the refrigerator (1000) may be configured as one door, and the upper door (3c) and the lower door (3d) on the left side of the refrigerator (1000) may be configured as one door. In addition, the number of doors of the refrigerator (1000) may be more or less than four. In addition, the position of the door (3) can also be varied. Between the plurality of doors (3a, 3b, 3c, 3d), there may be a handle area (4), which is a space where a user can insert a hand to open and close the door (3). The door (3) may be configured to seal the storage compartment when the door (3) is closed. The door (3) may include an insulating material, like the main body (1), to insulate the storage compartment (2) when the door (3) is closed.

[0104] The insulation material comprises rigid polyurethane foam. The rigid polyurethane foam comprises a urethane resin and microparticles containing polyol-derived structural units and isocyanate-derived structural units. The microparticles comprise a surface layer, which contains both hydrophobic and hydrophilic groups.

[0105] Since the surface layer of the fine particles simultaneously contains hydrophobic and hydrophilic groups, the balance between hydrophilicity and hydrophobicity in the polyol premix containing the fine particles is maintained, thereby suppressing phase separation and achieving a more uniform dispersion of the fine particles. Consequently, the rigid polyurethane foam produced from the polyol premix can have smaller, more uniform bubbles. Consequently, the insulation effect of a refrigerator equipped with an insulation material comprising the rigid polyurethane foam can be further enhanced. For example, the thickness of the insulation material can be reduced, thereby increasing the storage space.

[0106] Since the surface layer of the fine particles simultaneously contains hydrophobic and hydrophilic groups, the fine particles in the rigid polyurethane foam can be chemically bonded with the urethane resin and positioned within the skeleton comprising the urethane resin. Therefore, heat conduction through the skeleton comprising the urethane resin in the rigid polyurethane foam can be more effectively blocked or suppressed. Consequently, the insulation effect of a refrigerator equipped with an insulation material comprising the rigid polyurethane foam can be further enhanced. For example, the weight of the insulation material can be further reduced by reducing the content of the fine particles used in the polyurethane foam.

[0107] <Composition of rigid polyurethane foam according to the present embodiment>

[0108] The rigid polyurethane foam according to the present embodiment is formed by foaming and curing, thereby forming a plurality of bubbles, more preferably independent bubbles, inside. The overall density of this rigid polyurethane foam is 30 kg / m. 3 More than 45 kg / m 3 Below 32 kg / m 3 More than 40 kg / m 3 or less, or 32 kg / m 3 More than 38 kg / m 3 It could be as follows:

[0109] The above rigid polyurethane foam contains a urethane resin composed of a polyol-derived structural unit and an isocyanate-derived structural unit, a blowing agent forming the above-described bubbles, and fine particles.

[0110] Also, rigid polyurethane foam is a urethane foam that loses its resilience and cushioning properties after hardening, and is often used for insulation purposes.

[0111] Examples of the above polyol include polyether polyol and / or polyester polyol.

[0112] It is preferable that the above polyol-derived structural unit contains a structural unit (also referred to as a first structural unit) derived from an aromatic amine compound having 2 or more and 6 or less functional groups, to which both ethylene oxide and propylene oxide are added. Specific examples of the aromatic amine compound constituting the first structural unit include, for example, 2,3-toluenediamine, 2,4-toluenediamine, and 2,6-toluenediamine. The content of the first structural unit may be in the range of 65 mass% to 99 mass%, when the total of the polyol-derived structural units is 100 mass%.

[0113] The above polyol-derived structural unit may further contain a structural unit (also referred to as a second structural unit) derived from an aliphatic non-amine compound having 2 to 4 functional groups, to which ethylene oxide is added. Specific examples of the aliphatic non-amine compound constituting the second structural unit include ethylene glycol, propylene glycol, glycerin, pentaerythritol, and the like. In this case, the content of the second structural unit may be in the range of 1 to 10 mass%, based on 100 mass% of the total polyol-derived structural unit. By containing the aliphatic non-amine compound in the above-described range in the polyol-derived structural unit, steric hindrance due to aromatic rings can be suppressed, thereby improving the strength of the foam film. As a result, the foam can be made finer and a high gas barrier property can be imparted, so it is thought that the thermal conductivity of the fine particle-containing rigid polyurethane foam can be further reduced.

[0114] The above polyol-derived structural unit may contain a structural unit (also referred to as a third structural unit) derived from a compound to which a diol is added as an aromatic dicarboxylic acid having 2 to 4 functional groups in addition to the above-mentioned first structural unit. Specific examples of the aromatic dicarboxylic acid constituting the third structural unit include phthalic anhydride and terephthalic acid. Examples of the diol include diethylene glycol, 1,4-butanediol, 1,3-propanediol, and 3-methyl-1,5-pentanediol. In this case, when the total of the polyol-derived structural units is 100 mass%, the first structural unit may be contained in a range of 65 mass% to 99 mass%, and the third structural unit may be contained in a range of 1 mass% to 10 mass%. Since the above polyol-derived structural unit contains the first structural unit and the third structural unit, the aromatic rings of these structural units stack to further enhance the strength of the foam membrane. As a result, the foam can be made finer and a high gas barrier property can be imparted, thereby further reducing the thermal conductivity of the fine particle-containing rigid polyurethane foam.

[0115] In addition, the names of the first component unit, second component unit, and third component unit mentioned above are for convenience only and do not have any special meaning, such as, for example, when the third component unit is included, the first or second component unit must be included as a prerequisite.

[0116] As the above isocyanate, those conventionally used in rigid polyurethane foam can be widely used, but for example, polymeric MDI can be used.

[0117] Any foaming agent used in the manufacture of rigid polyurethane foam may be used as the foaming agent. However, for example, it is particularly preferable to use an organic solvent with a relatively low boiling point as the foaming agent. Specifically, a foaming agent having a boiling point of 55°C or lower, or a foaming agent having a boiling point of 50°C or lower, may be used. In the present embodiment, cyclopentane is used as an example of such a foaming agent.

[0118] The rigid polyurethane foam according to the present embodiment may contain additives such as a catalyst or a foaming agent (binder) in addition to the components described above.

[0119] Examples of catalysts include resinification catalysts, saturation catalysts, and trimerization catalysts. Using these catalysts containing tertiary amines can produce polyurethane foam that is as environmentally friendly as possible while minimizing manufacturing costs.

[0120] The foaming agent can be widely used as conventionally used in rigid polyurethane foam, but for example, a silicone-based foaming agent can be used.

[0121] The fine particles contained in the rigid polyurethane foam according to the present embodiment have an air layer (core), a spherical or polygonal shell, and a surface layer formed to cover the surface of the shell, as shown in FIG. 3.

[0122] The above-mentioned fine particles include a core, a shell disposed on the core, and a surface layer disposed on the shell, wherein the density of the core may be lower than the density of the shell.

[0123] The above shell may be made of an inorganic material having excellent strength or heat resistance, and examples thereof include hollow particles, porous particles, aerogels, and xerogels made of oxides such as silica or alumina.

[0124] The surface layer has both hydrophobic and hydrophilic groups. The surface layer is formed by a modifying group having both hydrophobic and hydrophilic groups, for example, a modifying group fixed through a chemical bond, such as a covalent bond, to the aforementioned shell.

[0125] The above-mentioned modifier is not particularly limited as long as it has one or more hydrophobic groups and one or more hydrophilic groups, but it is preferably a straight chain in which a bonding group for chemically bonding the shell and the modifier group, a hydrophobic group, and a hydrophilic group are bonded in this order from the side closer to the shell, as shown in Fig. 4. In addition, it may have a structure in which a bonding group, a hydrophobic group, and a hydrophilic group are arranged from the side closer to the shell, and then an additional hydrophobic group is present, or a structure in which pairs of hydrophobic groups and hydrophilic groups are repeated.

[0126] The above surface layer may be composed of only one type of modifier as described above, or may include two or more types of modifiers as described above.

[0127] Anything that can chemically bond the shell and the modifier may be used as the above bonding group. For example, if the shell is silica, a silane compound such as trimethoxysilane may be used.

[0128] As the hydrophobic group, examples thereof include a straight-chain hydrocarbon group having 1 to 10 carbon atoms, such as an ethyl group, a methyl group, a propyl group, or a cyclic hydrocarbon group, such as a benzene ring. The hydrophobic group may further include, for example, an aryl group having 4 to 10 carbon atoms.

[0129] As a hydrophilic group, it may have, for example, an amino group or a hydroxyl group.

[0130] One type or more types of hydrophobic groups from the surface treatment agent-derived group of one molecule may be included, and one type or more types of hydrophilic groups may be included. In addition, when multiple types of hydrophobic groups and / or hydrophilic groups are included in one modifying group, if the structure is such that a bonding group is present first, and then hydrophobic groups and hydrophilic groups are arranged alternately, the number and order thereof are not limited by the present disclosure.

[0131] The surface layer as described above can be formed by surface treating the shell using a surface treating agent such as a silane coupling agent having both a hydrophobic group and a hydrophilic group in a single molecule, for example. The surface treating agent may contain the same element as the fine particles, and the same element may include silicon. More specifically, the surface layer may be formed by chemically bonding the surface of the shell and the surface treating agent, for example, by covalent bonds, so that a plurality of the modifying groups are arranged to cover the surface of the shell. When the surface treating agent is linear, the modifying groups derived from the surface treating agent are arranged to extend outward from the surface of the shell. The surface layer may have hydrophobic groups and hydrophilic groups, and the hydrophilic groups may be arranged between the hydrophobic groups and the urethane resin. For example, the hydrophobic groups may be arranged on the fine particles, the hydrophilic groups may be arranged on the hydrophobic groups, and the urethane resin may be arranged on the hydrophilic groups.

[0132] From the perspective of lowering the thermal conductivity of the rigid polyurethane foam as much as possible, the thermal conductivity of the fine particles may be lower than the thermal conductivity of the urethane resin. The thermal conductivity of the fine particles may be, for example, 50 mW / m·K or less, 30 mW / m·K or less, or 20 mW / m·K or less. The thermal conductivity of the fine particles may be 90% or less, 80% or less, 70% or less, 50% or less, or 30% or less of the thermal conductivity of the urethane resin.

[0133] The apparent density of the above fine particles is 200 kg / m 3 or less, or 150 kg / m 3 It may be less than 200 kg / m2. The apparent density of the fine particles may be less than 200 kg / m2. 3 Below this, the viscosity of the polyol mix does not become too high, which is preferable because it can further suppress the occurrence of the aforementioned voids. As the apparent density of the fine particles decreases, the insulating performance of the rigid polyurethane foam improves, so the smaller the apparent density of the fine particles, the better.

[0134] In addition, the apparent density can be obtained by converting the apparent density (g / ml) obtained by placing 100 g of fine particle powder in a measuring cylinder, smoothing the upper surface, and reading the apparent volume (V0) (unit: ml).

[0135] The average particle size of the above-mentioned fine particles may be 0.03 μm or more and 20 μm or less, 0.05 μm or more and 10 μm or less, or 0.04 μm or more and 5 μm or less. When the average particle size of the fine particles is 0.03 μm or more, the bubble growth inhibition effect due to the presence of the fine particles can be sufficiently exerted. In addition, when the average particle size of the fine particles is 20 μm or less, the number of fine particles contained in the rigid polyurethane foam can be sufficiently secured to sufficiently exert the bubble growth inhibition effect. The average particle size of the fine particles can be measured by observation with a scanning electron microscope.

[0136] In addition, the shape of the fine particles may be any shape such as a sphere, a spherical ellipse, other geometric shapes, or an irregular shape, but may be, for example, a sphere or a spherical ellipse. The shape factor, which is the quotient of the sum of the major axis length divided by the minor axis length and the irregularity coefficient (the cross-sectional area in a plane including the major axis and the minor axis divided by the square of the outer circumference length) divided by 2, may be, for example, 120 or less, 115 or less, 110 or less, or 105 or less.

[0137] In the rigid polyurethane foam according to the present embodiment, the content of the fine particles may be, for example, 0.01% by volume or more and 1.0% by volume or less, or 0.05% by volume or more and 0.5% by volume or less, when the volume of the entire rigid polyurethane foam is 100% by volume.

[0138] By setting the content of fine particles to 0.01% by volume or more, the number of particles per bubble can be set to 1 or more, so that bubbles can be reliably made fine. In addition, by setting the content of fine particles to 1.0% by volume or less, the viscosity of the polyol mix, which is a material of rigid polyurethane foam containing polyol and the like before foaming and curing, can be suppressed from becoming too high, thereby suppressing an increase in thermal conductivity caused by large bubbles generated in the urethane foam not being eliminated but being formed as voids.

[0139] In addition, the viscosity of the polyol premix can be adjusted depending on the type of polyol mix or isocyanate used in addition to the above, and may be, for example, 500 mPa·s or more and 2000 mPa·s or less, 500 mPa·s or more and 1500 mPa·s or less, or 700 mPa·s or more and 1300 mPa·s or less.

[0140] <Method for producing rigid polyurethane foam according to the present embodiment>

[0141] The rigid polyurethane foam according to the present embodiment can be manufactured, for example, by the following sequence and process.

[0142] First, a mixture containing polyether polyol and / or polyester polyol is adjusted, and this mixture and fine particles are mixed in an open atmosphere at room temperature, and then a foaming agent is added and mixed in a closed space at 20 to 25 degrees Celsius, thereby adjusting a polyol premix.

[0143] A rigid polyurethane foam can be manufactured by adding isocyanate to the above polyol premix, stirring, pouring the mixture into an appropriate mold, and allowing it to foam freely at an appropriate temperature.

[0144] The above polyol premix may further contain a foaming aid, and when containing the foaming aid, the content of the foaming aid in the polyol premix may be 0.5 mass% or more and 2.0 mass% or less. There is no particular limitation on the foaming aid, but water may be used from the viewpoint of achieving both high reaction efficiency and low cost.

[0145] <Effects of this embodiment>

[0146] According to the rigid polyurethane foam of the present embodiment, since the fine particles have a surface layer having hydrophobic and hydrophilic groups, even when the fine particles are incorporated into a polyol premix, the balance between hydrophilicity and hydrophobicity in the polyol premix is ​​not disrupted, thereby suppressing the separation of hydrophobic components or fine particles. As a result, as illustrated in Fig. 5, the size of the bubbles can be made small and uniform throughout the rigid polyurethane foam.

[0147] In addition, if the number of hydrophilic groups included in the surface layer is large, the formation of chemical bonds forming the urethane resin can be further promoted, thereby promoting the curing of the urethane resin, so that the urethane resin can be cured before the bubbles become too large, and the growth of the bubbles can be more effectively suppressed.

[0148] Referring to FIG. 6, the rigid polyurethane foam may include, for example, a skeleton comprising the urethane resin; and a plurality of pores defined by the skeleton; and may include the microparticles disposed within the skeleton and spaced apart from the pores. The microparticles may be fixed within the skeleton through chemical bonding with the urethane resin. The chemical bond may include a urea group, a urethane group, or a combination thereof.

[0149] The hydrophilic group included in the aforementioned modifier can form a direct chemical bond with the urethane resin constituting the urethane resin through a urethane bond or urea bond. Therefore, fine particles with lower thermal conductivity than the urethane resin are introduced into the urethane framework forming the urethane resin, making it difficult for heat, which was previously transmitted along the urethane framework of the urethane resin, to be transmitted, as illustrated in Fig. 6.

[0150] Since the surface layer is formed by a linear modifying group in which hydrophobic and hydrophilic groups appear in this order from the side closer to the shell, and further by a modifying group having a structure in which hydrophobic and hydrophilic groups appear repeatedly, the hydrophilic groups included in these modifying groups are easily accessible to polyol or isocyanate, making it easy for the fine particles to be introduced into the urethane skeleton.

[0151] According to the rigid polyurethane foam containing fine particles according to the present embodiment, the fine particles are contained in a ratio of 0.05% by volume or more and 0.35% by volume or less per 100% by volume of the rigid polyurethane foam containing fine particles after foaming and curing, so that the number of fine particles contained per volume of the rigid polyurethane foam is prevented from becoming extremely large or small, and even when the type of fine particles is changed, the number of fine particles necessary to make the bubbles fine is present in the rigid polyurethane foam containing fine particles, thereby suppressing the growth of bubbles during foaming.

[0152] The fine particle-containing rigid polyurethane foam according to the present embodiment can be used for various purposes as an insulating material. Since the thermal conductivity is sufficiently low and the manufacturing cost can be suppressed within an appropriate range, it can be suitably used as an insulating material for home appliances such as refrigerators, for example.

[0153] Since the rigid polyurethane foam containing fine particles has lower thermal conductivity than conventional foam, it can exhibit insulation performance equivalent to that of conventional foam even with a smaller thickness. Furthermore, when used as insulation between the outer case and inner case of a refrigerator, the thickness of the insulation layer between the outer case and inner case can be reduced, thereby increasing the volume of the inner case (refrigerating compartment) compared to conventional foam.

[0154] Below, the definitions of substituents used in chemical formulas are explained.

[0155] The term "alkyl" as used in chemical formulas refers to a fully saturated branched or unbranched (or straight-chain or linear) hydrocarbon.

[0156] Non-limiting examples of the above “alkyl” include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, and the like.

[0157] One or more hydrogen atoms of the above "alkyl" are selected from the group consisting of a halogen atom, a C1-C30 alkyl group substituted with a halogen atom (e.g., CCF3, CHCF2, CH2F, CCl3, etc.), a C1-C30 alkoxy, a C2-C30 alkoxyalkyl, a hydroxy group, a nitro group, a cyano group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxyl group or a salt thereof, a sulfonyl group, a sulfamoyl group, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, or a C1-C30 alkyl group, a C2-C30 alkenyl group, a C2-C30 alkynyl group, a C1-C30 heteroalkyl group, a C6-C30 aryl group, a C7-C30 arylalkyl group, a C2-C30 heteroaryl group, a C3-C30 It may be substituted with a heteroarylalkyl group, a C2-C30 heteroaryloxy group, a C3-C30 heteroaryloxyalkyl group, or a C6-C30 heteroarylalkyloxy group.

[0158] The term "alkylene" as used in chemical formulas refers to the diradical "alkyl," where alkyl is as described above. A diradical is, for example, an alkyl group requiring two bonding points. Alkylene groups include, for example, diradicals such as -CH2-, -CH2CH2-, -CH2CH(CH3)CH2-, etc.

[0159] Non-limiting examples of the above “alkylene” include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, sec-butylene, n-pentylene, isopentylene, neopentylene, n-hexylene, 3-methylhexylene, 2,2-dimethylpentylene, 2,3-dimethylpentylene, n-heptylene, and the like.

[0160] The term "aryl" group as used in chemical formulas, used alone or in combination, refers to an aromatic hydrocarbon group containing one or more rings. The number of carbon atoms in an aryl group is, for example, 4 to 20, 4 to 15, or 4 to 10.

[0161] The term "aryl" also includes groups in which an aromatic ring is fused to one or more cycloalkyl rings.

[0162] Non-limiting examples of the above “aryl” include phenyl, naphthyl, tetrahydronaphthyl, etc.

[0163] Additionally, one or more hydrogen atoms in the above “aryl” group may be substituted with a substituent similar to that in the case of the above-described alkyl group.

[0164] The present invention is not limited to the above-described embodiments, and various modifications or combinations of embodiments may be made as long as they do not conflict with the spirit of the present invention.

[0165] Example

[0166] Hereinafter, the present invention will be described in more detail based on specific examples. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0167] First, each mixture as described in Table 1 or Table 2 below was prepared. In these Examples and Comparative Examples, the viscosity of the polyol premix measured under 20°C conditions using TVC-10 manufactured by Toki Sangyo was 950 mPa·s. The mixture, adjusted to a liquid temperature of 25°C, was stirred at 5000 rpm for 4 seconds with a hand mixer. Thereafter, the mixture was poured into a 300 mm Х 300 mm Х 30 mm wooden box controlled at a temperature of 42°C to 44°C and allowed to foam freely, thereby preparing rigid polyurethane foams of the Examples and Comparative Examples. Table 1 shows the content of the chemical component including fine particles in wt% with respect to the entire rigid polyurethane foam for the Examples and Comparative Examples, and Table 2 shows the content of fine particles in volume% with respect to the entire rigid polyurethane foam after foaming for the Examples and Comparative Examples shown in Table 1.

[0168]

[0169] The specific details of each component in Table 1 are as follows.

[0170] Polyol: 70 wt% aromatic amine polyol, 30 wt% sorbitol polyol, 3.0 wt% tertiary amine catalyst, 2.5 wt% silicone foam stabilizer, 1.8 wt% water

[0171] Blowing agent: Cyclopentane Maruzen Petroleum Manufacturing Marucazole FH

[0172] Isocyanate: Tosoh Manufacturing MR200 Index 110

[0173] Particulate shell A: Hollow silica with an apparent density of 90 kg / m 3 More than 140 kg / m 3 Below, average particle diameter (D50) 2 μm

[0174] Particulate shell B: Hollow silica with an apparent density of 40 kg / m 3 More than 90 kg / m 3 Below, average particle diameter (D50) 0.1 μm

[0175] Surface Formula I: 3-(N-phenyl)aminopropyltrimethoxysilane

[0176] Surface Formula II: Aminopropyltrimethoxysilane

[0177] Surface Formula III: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane

[0178]

[0179] The volume of the rigid polyurethane foam in Table 2 was calculated from the density of each rigid polyurethane foam and the total mass of the polyol, blowing agent, and isocyanate in Table 1.

[0180] Next, the performance of these examples and comparative examples was evaluated by the method shown below, and the results are shown in Table 3. In addition, microscopic photographs for each example and comparative example are shown in Figs. 7 and 8.

[0181] <Measurement of thermal conductivity>

[0182] For each example and comparative example of a rigid polyurethane foam containing fine particles or a rigid polyurethane foam not containing fine particles after foaming and curing, the thermal conductivity of a rigid polyurethane foam having a size of 300 mm Х 300 mm Х 30 mm thick was measured at an average temperature of 20°C using a NETZSCH normal method thermal conductivity measuring device (HFM436).

[0183] <Measurement of bubble size>

[0184] Using a digital microscope VHX-5000 manufactured by Keyence, the bubble diameters of 10 random bubbles within the field of view were measured, and the bubble size (D50) was calculated from the average value.

[0185] <Measurement of the density of the entire fine particle rigid polyurethane foam>

[0186] The weight of rigid polyurethane foam measuring 300 mm Х 300 mm Х and 30 mm thick was measured using an electronic balance, and the density of the entire foam was calculated from the volume of the entire rigid polyurethane foam.

[0187]

[0188] From the results of the examples and comparative examples shown in Table 3, Figures 7 and 8, it can be seen that when the surface layer of the fine particles contained in the rigid polyurethane foam has both hydrophobic and hydrophilic groups as shown in Examples 1 to 9, a rigid polyurethane foam can be made with a sufficient expansion ratio without phase separation occurring at the stage of adjusting the polyol premix, and the thermal conductivity can be made smaller compared to the case where the fine particles are not added.

[0189] On the other hand, as shown in Comparative Examples 10 to 13, when the surface layer of the fine particles contained in the rigid polyurethane foam is hydrophobic, even when the content is 0.14 wt%, the hydrophobic fine particles are separated from the polyol premix, and not only is the effect of reducing the thermal conductivity by including the fine particles not observed, but on the contrary, the thermal conductivity becomes greater than that of Comparative Example 14 in which the fine particles are not added. In addition, in Comparative Examples 11 to 13 in which the surface of the fine particles is hydrophilic, the polyol premix is ​​foamed and cured immediately after mixing, so the thermal conductivity can be reduced, but when the polyol premixes of these Comparative Examples 11 to 13 are left to stand for 10 hours or more as in mass production, the hydrophobic blowing agent is separated from the polyol premix, resulting in a failure to obtain a sufficient foaming ratio.

[0190] According to the present invention, a refrigerator can be provided in which the thermal conductivity of rigid polyurethane foam is further reduced compared to conventional ones.

Claims

1. Internal cavity forming a storage room; trauma to the outer surface of the above-mentioned inner surface; and A body including an insulating material between the inner and outer surfaces; and A door configured to open and close the storage room is included, The above insulation material comprises rigid polyurethane foam, The above rigid polyurethane foam Fine particles each comprising a surface layer comprising a hydrophobic group and a hydrophilic group; and A refrigerator comprising a urethane resin containing a constituent unit derived from polyol and a constituent unit derived from isocyanate.

2. In paragraph 1, The above surface layer includes a modifying group chemically bonded to the surface of the fine particles, A refrigerator, wherein the above-mentioned modifier is derived from a surface treatment agent and contains a hydrophobic group and a hydrophilic group.

3. In paragraph 1, The above hydrophilic group is an amino group or a hydroxyl group, A refrigerator, wherein the above-mentioned hydrocarbon group is a straight-chain alkyl group having 1 to 10 carbon atoms.

4. In paragraph 1, A refrigerator, wherein the hydrophilic group is between the hydrophobic group and the urethane resin.

5. In paragraph 1, A refrigerator, wherein the above-mentioned hydrocarbon group comprises an aryl group having 4 to 10 carbon atoms.

6. In paragraph 1, The above fine particles contain inorganic materials, A refrigerator, wherein the above particles are hollow particles or porous particles.

7. In paragraph 2, A refrigerator, wherein the surface treatment agent and the fine particles contain silicon.

8. In paragraph 1, The above fine particles include a core, a shell on the core, and a surface layer on the shell, A refrigerator wherein the density of the core is lower than the density of the shell.

9. In paragraph 1, The above rigid polyurethane foam, A skeleton comprising the above urethane resin; and A plurality of pores defined by the above skeleton; A refrigerator wherein the above particles are arranged inside the frame and each particle is separated from the pores by at least a urethane resin.

10. In paragraph 1, The above particles are each fixed inside the skeleton through chemical bonding with the urethane resin, A refrigerator, wherein the chemical bond comprises a urea group, a urethane group or a combination thereof.

11. In paragraph 1, A refrigerator, wherein the content of the above fine particles in the rigid polyurethane foam is 0.01% by volume or more and 0.5% by volume or less.

12. In paragraph 1, A refrigerator, wherein the content of the above fine particles in the rigid polyurethane foam is 0.1 wt% or more and 1.5 wt% or less.

13. In paragraph 1, The average particle size of the above fine particles is 0.03 μm or more and 20 μm or less, The apparent density of the above particles is 200 kg / m 3 Lee Ha-in, refrigerator.

14. In paragraph 1, A refrigerator, wherein the rigid polyurethane foam further comprises a blowing agent containing an organic compound.

15. In paragraph 1, A cold air supply device that supplies cold air to the above storage room, A machine room accommodating at least a portion of the components belonging to the above refrigeration supply device; and A refrigerator further comprising a processor controlling the refrigerator.

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