PCM steel sheet for home appliances and refrigerator comprising same

Abstract

A PCM steel sheet for home appliances according to an embodiment disclosed herein may comprise: a steel sheet; a base coating layer disposed on the steel sheet and including a cured resin; a print layer disposed on the base coating layer and including a UV ink; and a film layer disposed on the print layer. The base coating layer may contain an auxiliary resin that is chemically bondable to the cured resin and the UV ink. The auxiliary resin may constitute 1.0-1.5 wt% of the total weight of the base coating layer.

Description

PCM steel sheet for home appliances and refrigerators containing the same

[0001] Various embodiments of the present disclosure relate to a PCM steel sheet for home appliances and a refrigerator including the same.

[0002] Home appliances like refrigerators may incorporate steel sheets to create their exterior appearance. These sheets can be either pre-coated metal (PCM) or vinyl-coated metal (VCM). To achieve a variety of patterns tailored to consumer needs, VCM, a high-gloss and high-reflection steel sheet, may be a better choice than PCM. However, the use of VCM has the disadvantage of increasing production costs.

[0003] Various embodiments of the present disclosure can secure interlayer adhesion of film layers by controlling the composition of the base coating layer in a PCM steel plate using a digital printing method.

[0004] A PCM steel sheet for a home appliance according to one embodiment of the present disclosure may include a steel sheet, a base coating layer disposed on the steel sheet and including a cured resin, a print layer disposed on the base coating layer and including UV ink, and a film layer disposed on the print layer. The base coating layer may include an auxiliary resin chemically bondable to the cured resin and the UV ink. The auxiliary resin may be present in an amount of 1.0 to 1.5 wt% based on the total weight of the base coating layer.

[0005] A refrigerator according to one embodiment of the present disclosure may include a main body, a storage compartment provided inside the main body, and a door coupled to the main body to open and close at least a portion of the storage compartment. The door may include a PCM steel plate. The PCM steel plate may include a steel plate, a base coating layer disposed on the steel plate and including a curable resin, a print layer disposed on the base coating layer and including UV ink, and a film layer disposed on the print layer. The base coating layer may include an auxiliary resin chemically bondable to the curable resin and the UV ink. The auxiliary resin may be present in an amount of 1.0 to 1.5 wt% based on the total weight of the base coating layer.

[0006] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from implementing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0007] Figure 1 is a perspective view of a refrigerator according to one embodiment.

[0008] FIG. 2 is a perspective view of a refrigerator with the door open according to one embodiment.

[0009] FIG. 3 is a schematic diagram illustrating a PCM steel plate for home appliances according to one embodiment.

[0010] Figures 4 and 5 are graphs showing the relationship between the gloss of the base coating layer and the gloss of the clear coating layer in the PCM steel plate of Figure 3.

[0011] Figures 6 and 7 are graphs showing the gloss and distinctness of image (DOI) of the clear coating layer according to the type of hardener and the addition ratio of the matting agent in the PCM steel plate of Figure 3.

[0012] Fig. 8 is an experimental example to explain the clarity of the print layer according to the ratio of the matting agent added to the base coating layer in the PCM steel plate of Fig. 3.

[0013] FIG. 9 is a cross-sectional view of a PCM steel plate according to one embodiment of the present disclosure.

[0014] FIG. 10 is a cross-sectional view of a PCM steel plate according to one embodiment of the present disclosure.

[0015] Figure 11 is a cross-sectional view of a PCM steel plate according to one embodiment of the present disclosure.

[0016] The accompanying drawings are referenced in the following description, and specific examples of implementations are illustrated within the drawings. Furthermore, other examples may be utilized and structural changes may be made without departing from the scope of the various examples.

[0017] It should be understood that the various embodiments of the present disclosure and the terminology used therein are not intended to limit the technical features described in the present disclosure to specific embodiments, but rather include various modifications, equivalents, or substitutes of the embodiments.

[0018] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0019] 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.

[0020] 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.

[0021] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] A refrigerator according to one embodiment may include a body.

[0028] The "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.

[0029] The "inner case" may include at least one of a case, a plate, a panel, or a liner forming a storage compartment. The inner case may be formed as a single body, or may be formed by assembling a plurality of plates. The "outer case" may form the outer appearance of the main body, and may be joined to the outer side of the inner case so that insulation is placed between the inner case and the outer case.

[0030] "Insulation" can 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. In one embodiment, the insulation can include foam insulation. The foam insulation can be formed by injecting and foaming urethane foam, a mixture of polyurethane and a foaming agent, between the inner and outer layers.

[0031] In one embodiment, the insulation may include a vacuum insulation material in addition to the foam insulation, or the insulation may consist solely of the vacuum insulation material instead of the foam insulation. The vacuum insulation material may 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. However, the insulation material is not limited to the foam insulation or vacuum insulation material described above, and may include various materials that can be used for insulation.

[0032] A "storage room" may include a space defined by an interior wall. The storage room may further include an interior wall defining a corresponding space. The storage room may store various items, such as food, medicine, and cosmetics, and the storage room may be configured to be open on at least one side for the entry and exit of items.

[0033] A refrigerator may include one or more storage compartments. When a refrigerator includes 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.

[0034] The storage room may be designed to maintain an appropriate temperature range depending on its intended use, and may include a "refrigerator," a "freezer," or a "variable temperature room," which are distinguished by their intended use and / or temperature range. A refrigerator may be maintained at a temperature appropriate for refrigerating items, and a freezer may be maintained at a temperature appropriate for freezing items. "Refrigeration" may mean cooling items to a temperature that does not freeze them, and for example, a refrigerator may be maintained at a temperature ranging from 0 degrees Celsius to +7 degrees Celsius. "Freezing" may mean cooling items to freeze them or keep them frozen, and for example, a freezer may be maintained at a temperature ranging from -20 degrees Celsius to -1 degree Celsius. A variable temperature room may be used as either a refrigerator or a freezer, at the user's option or not.

[0035] In addition to names such as "refrigerator," "freezer," and "variable temperature room," a storage room may also be called by various other names such 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 having corresponding uses and temperature ranges.

[0036] In one embodiment, the refrigerator may include at least one door configured to open and close an open side of a storage compartment. The door may be configured to open and close one or more storage compartments, or a single door may be configured to open and close multiple storage compartments. The door may be installed on the front of the main body in a pivotal or sliding manner.

[0037] The "door" may be configured to seal the storage compartment when the door is closed. The door may include insulation, similar to the body, to insulate the storage compartment when the door is closed.

[0038] According to one embodiment, the door may include 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 on the interior of these.

[0039] The door inner panel may be provided with a gasket that seals the storage compartment by contacting 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.

[0040] In one embodiment, the door may include a door body and a front panel detachably coupled to the front side of the door body and forming the front of the door. The door body may include 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.

[0041] Depending on the arrangement of the door and storage compartment, refrigerators can be classified into French door type, side-by-side type, bottom mounted freezer (BMF), top mounted freezer (TMF), or single-door refrigerator.

[0042] According to one embodiment, the refrigerator may include a cold air supply device configured to supply cold air to the storage compartment.

[0043] A "cold air supply device" may include a system of machines, devices, electronic devices and / or combinations thereof that can generate cold air and guide the cold air to cool a storage room.

[0044] In one embodiment, the cold air 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 cold air supply device can include a refrigeration cycle device having a compressor, a condenser, an expansion device, and an evaporator capable of driving the refrigeration cycle. In one embodiment, the cold air supply device can include a semiconductor, such as a thermoelectric element. The thermoelectric element can cool a storage compartment by generating heat and cooling through the Peltier effect.

[0045] According to one embodiment, the refrigerator may include a machine room in which at least some components belonging to the cold air supply device are arranged.

[0046] The "machine room" may be designed to be partitioned and insulated from the storage room to prevent heat generated by components placed within the machine room from being transferred to the storage room. The interior of the machine room may be configured to be in communication with the exterior of the main body to dissipate heat from components placed within the machine room.

[0047] In one embodiment, the refrigerator may 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 a user without having to open the door.

[0048] In one embodiment, a refrigerator may include an ice-making device configured to produce ice. The ice-making device may include an ice-making tray configured to store water, an ice-separating device configured to separate ice from the ice-making tray, and an ice bucket configured to store ice produced in the ice-making tray.

[0049] According to one embodiment, the refrigerator may include a control unit for controlling the refrigerator.

[0050] The "control unit" may include a memory that stores or memorizes a program and / or data for controlling the 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.

[0051] Memory stores or records various information, data, commands, programs, etc. necessary for the operation of the refrigerator. Memory can store temporary data generated during the generation of control signals for controlling components within the refrigerator. Memory may include at least one of volatile memory and non-volatile memory, or a combination thereof.

[0052] The processor controls the overall operation of the refrigerator. The processor can control the components of the refrigerator by executing programs stored in memory. The processor may include a separate NPU that performs the operations of an artificial intelligence model. The processor may also include a central processing unit (CPU), a graphics processing unit (GPU), or the like. The processor may generate control signals to control the operation of the cooling system. For example, the processor may receive temperature information about the storage compartment from a temperature sensor and generate a cooling control signal to control the operation of the cooling system based on the temperature information.

[0053] 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.

[0054] The processor and memory may be provided as a single unit or separately. The processor may include one or more processors. For example, the processor may include a main processor and at least one subprocessor. The memory may include one or more memories.

[0055] In one embodiment, a refrigerator may include a processor and memory that control all components within the refrigerator, and may 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. Additionally, the refrigerator may separately include a processor and memory that control the operation of a user interface based on user input.

[0056] 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.

[0057] The input interface may include keys, a touchscreen, a microphone, etc. The input interface may receive user input and transmit it to the processor.

[0058] The output interface may include a display, a speaker, etc. The output interface may output various notifications, messages, information, etc. generated by the processor.

[0059] Figure 1 is a perspective view of a refrigerator according to one embodiment.

[0060] FIG. 2 is a perspective view of a refrigerator with the door open according to one embodiment.

[0061] The refrigerators illustrated in FIGS. 1 and 2 are of the side-by-side type, but this is exemplary and the scope of the present disclosure is not limited to side-by-side type refrigerators.

[0062] Referring to FIGS. 1 and 2, the refrigerator (1) may include at least one of a main body (10), a dispenser (20), a door (30), or a cover member (50).

[0063] According to an example, the main body (10) may include an outer case (11) or an inner case (12). The inner case (12) may be provided to form, for example, an outer appearance of a storage compartment (13). The inner case (12) may be configured to define a shape of the storage compartment (13). The inner case (12) may be integrally injection-molded, for example, and made of a plastic material. The outer case (11) may be provided to form, for example, at least a portion of the outer appearance of the refrigerator (1). The outer case (11) may be made of, for example, a metal material having excellent durability and finish, but is not limited thereto.

[0064] According to one embodiment, the trauma (11) may include a PCM steel plate (e.g., PCM steel plate (300) of FIG. 3, PCM steel plates (300-1, 300-2, 300-3) of FIGS. 9 to 11) to be described later.

[0065] According to one embodiment, the inner surface (12) may include a PCM steel plate (e.g., PCM steel plate (300) of FIG. 3, PCM steel plates (300-1, 300-2, 300-3) of FIGS. 9 to 11) to be described later.

[0066] According to an example, a receiving space may be formed between the outer case (11) and the inner case (12). The main body (10) may include a foaming agent (or insulating material) for insulating the storage compartment (13). The foaming agent may be filled in the receiving space between the outer case (11) and the inner case (12). A portion of the receiving space may be provided with a foaming agent (or insulating material) of an insulating material for insulating the storage compartment (13).

[0067] According to one example, the outer surface (11) may include an upper surface (11a), a side surface (11b) extending approximately perpendicular to the upper surface (11a) and having an outer surface facing the +y direction or the -y direction, and a rear surface (11c) extending from the upper surface (11a) and having an outer surface facing the -x direction. The side surface (11b) and the rear surface (11c) may be arranged to be adjacent to each other. The side surface (11b) and the rear surface (11c) may be arranged approximately perpendicular to each other. The upper surface (11a), the side surface (11b), and the rear surface (11c) may be formed integrally, but are not limited thereto. Although not illustrated, the outer surface (11) may include a lower surface facing a bottom surface.

[0068] In one example, the front (e.g., +x direction) of the main body (10) can be opened. A user can store food in the storage compartment (13) through the front of the main body (10).

[0069] According to an example, the main body (10) may include a storage compartment (13). The storage compartment (13) may be defined by an inner case (12). The storage compartment (13) may be a space formed to store food and refrigerate or freeze it.

[0070] According to an example, the storage compartment (13) may include a first storage compartment (131) or a second storage compartment (132). The number of storage compartments (13) may vary depending on the type of refrigerator. The first storage compartment (131) and the second storage compartment (132) may be partitioned by a partition wall (14). The refrigerator (1) may include a partition wall (14) extending in a vertical direction (e.g., z-axis direction). The first storage compartment (131) may be formed on one side of the partition wall (14) and the second storage compartment (132) may be formed on the other side. The sizes of the first storage compartment (131) and the second storage compartment (132) may vary depending on the position of the partition wall (14). The space between the first storage compartment (131) and the second storage compartment (132) may be insulated by the partition wall (14). The shape and number of the bulkhead (14) may vary depending on the type of refrigerator (1).

[0071] For example, one of the first storage compartment (131) and the second storage compartment (132) may be a refrigerator and the other may be a freezer. The temperature of the freezer may be approximately -18 degrees Celsius to -23 degrees Celsius. The temperature of the refrigerator may be approximately 0 degrees Celsius to +7 degrees Celsius. For example, the first storage compartment (131) may be a freezer and the second storage compartment (132) may be a refrigerator, but is not limited thereto.

[0072] In one example, the first storage compartment (131) may be configured to store food at a first temperature. In one example, the second storage compartment (132) may be configured to store food at a second temperature. The second temperature may be higher than the first temperature. The first temperature may be a temperature between -18 degrees Celsius and -23 degrees Celsius, but the range is not limited thereto. The second temperature may be a temperature between 0 degrees Celsius and +7 degrees Celsius, but the range is not limited thereto. Hereinafter, a case in which the first storage compartment (131) is a freezer and the second storage compartment (132) is a refrigerator will be described as an example.

[0073] According to an example, the front (e.g., +x direction) of the storage room (13) can be formed to be open. The front of the storage room (13) can be opened and closed by a door (30).

[0074] According to one example, the door (30) may be provided to open and close the opening of the main body (10). The door (30) may be provided to open and close the storage compartment (13). The door (30) may be provided in a double-door type to open and close the first storage compartment (131) and the second storage compartment (132), but is not limited thereto. The door (30) may be configured to rotate around a hinge. The door (30) may be coupled to the main body (10) by the hinge so as to be rotatable with respect to the main body (10). The refrigerator (1) may include a first hinge provided to rotatably couple the first door (31) to the main body (10). The refrigerator (1) may include a second hinge provided to rotatably couple the second door (32) to the main body (10).

[0075] According to an example, the door (30) may include a first door (31) and a second door (32). The first door (31) may be arranged to open and close the first storage compartment (131). The second door (32) may be arranged to open and close the second storage compartment (132).

[0076] According to one embodiment, the door (30) may include a PCM steel plate (e.g., PCM steel plate (300) of FIG. 3, PCM steel plates (300-1, 300-2, 300-3) of FIGS. 9 to 11) to be described later.

[0077] According to one example, the dispenser (20) may be configured to supply at least one of water or ice. The dispenser (20) may include a water intake space into which a container, such as a cup, may be inserted to obtain water or ice. The dispenser (20) may include an operating lever that may be operated to discharge water or ice. The dispenser (20) may be supplied with water from an external water source. For example, the dispenser (20) may be supplied with water directly or indirectly from a water supply pipe.

[0078] In one example, the dispenser (20) may be installed in the door (30). For example, the dispenser (20) may be installed in the door that opens and closes the freezer. For example, the dispenser (20) may be installed in the first door (31) that opens and closes the first storage compartment (131).

[0079] For example, a refrigerator (1) may include an ice maker (60). Ice may be produced in the ice maker (60). A dispenser (20) may receive ice from the ice maker (60) and discharge the ice into a water intake space. A connecting space may be provided between the ice maker (60) and the dispenser (20) for the movement of ice. The ice maker (80) may receive water from an external water source. The ice maker (60) may receive water directly or indirectly from, for example, a water supply pipe (600).

[0080] According to one example, the cover member (50) may be disposed on the upper side of the outer body (11). For example, the cover member (50) may be disposed on the upper surface of the outer body (11). The cover member (50) may be formed with an open lower side. A portion of the cover member (50) may be disposed to cover a hinge that rotatably connects the door (30) to the main body (10).

[0081] According to one example, the cover member (50) may include a top surface (50a), a front surface (50b) extending in a substantially vertical direction from a front edge of the top surface (50a), and a rear surface (50c) positioned opposite the front surface (50b) and extending in a substantially vertical direction from a rear edge of the top surface (50b). The front surface (50b) may be a surface facing approximately in the +x direction. The rear surface (50c) may be a surface facing approximately in the -x direction.

[0082] According to one example, the cover member (50) may include at least one through hole (51). Outside air may flow into the interior of the cover member (50) through the at least one through hole (51). As an example, the at least one through hole (51) may be located on the upper surface (50a) of the cover member (50), but is not limited thereto.

[0083] According to an example, the cover member (50) may include a hinge cover portion (52). The hinge cover portion (52) may be a portion that covers the hinge of the door (30). The hinge cover portion (52) may be arranged as a part of the cover member (50) to cover the hinge so that it is not visible from the outside.

[0084] For example, a refrigerator (1) may include a machine room (40). The machine room (40) may be arranged at the lower part of the main body, but is not limited thereto. A cold air generating unit may be arranged within the machine room (40). The cold air generating unit may be provided within the main body (10) to supply cold air to, for example, a storage room (20).

[0085] For example, a cold air generating unit can generate cold air by utilizing a cooling cycle of compressing, condensing, expanding, and evaporating a refrigerant. For example, a compressor (not shown) that compresses a refrigerant and discharges it in a high-temperature and high-pressure state, a condenser (not shown) that condenses the high-temperature and high-pressure refrigerant compressed by the compressor through heat dissipation, and a condensing fan (not shown) that cools the condenser are disposed in the machine room (40).

[0086] FIG. 3 is a schematic diagram illustrating a PCM steel plate for home appliances according to one embodiment.

[0087] The PCM steel plate (300) of FIG. 3 may be included in the refrigerator (1) illustrated in FIGS. 1 and 2. The PCM steel plate (300) of FIG. 3 may constitute at least a portion of the outer case (e.g., the outer case (11) of FIG. 2), the inner case (e.g., the inner case (12) of FIG. 2), and the door (e.g., the door (30) of FIG. 2) of the refrigerator (1) of FIGS. 1 and 2.

[0088] Referring to FIG. 3, the PCM steel plate (300) may include a steel plate (310), a base coating layer (320) disposed on the steel plate (310), a print layer (330) disposed on the base coating layer (320), a clear coating layer (350) disposed on the print layer (330), and an adhesive layer (340) disposed to bond between the print layer (330) and the clear coating layer (350).

[0089] According to one embodiment, the steel plate (310) may be an electrolytic galvanized iron (EGI) steel plate or a galvanized iron (GI) steel plate. However, the present invention is not limited thereto, and the type of steel plate may vary depending on the purpose and function. For example, various types of steel plates, such as stainless steel and cold-rolled steel plates, may be applied as the steel plate (310).

[0090] According to one embodiment, the base coating layer (320) may be composed primarily of a polyester-based (PE) resin. The base coating layer (320) may include a melamine curing agent, an isocyanate curing agent, and a matting agent for controlling surface tension. Various colors and patterns may be applied to the base coating layer (320).

[0091] Table 1 below exemplarily shows the composition ratio of some of the materials constituting the base coating layer (320). The unit of each composition is weight %.

[0092] In addition to the materials shown in [Table 1], various materials may be added to the base coating layer (320).

[0093] Classification Example 1-1 Example 1-2 Example 1-3 Polyester (PE) resin 58 ~ 78 60 ~ 75 60 ~ 75 Melamine 1 ~ 50 1 ~ 3 Isocyanate 0 1 ~ 51 ~ 3 Matting agent 0 ~ 100 ~ 100 ~ 10

[0094] As described in [Table 1], the base coating layer (320) may have the composition of one of Example 1-1, Example 1-2, or Example 1-3, but this is exemplary, and the composition ratio of the base coating layer (320) is not limited thereto.

[0095] According to one embodiment, the base coating layer (320) may include 0 wt% to 10 wt% of a matting agent.

[0096] In one embodiment, the base coating layer (320) may include at least one of a melamine curing agent or an isocyanate curing agent. For example, the base coating layer (320) may include 1 wt% to 5 wt% of a melamine curing agent, as in Example 1-1. For example, the base coating layer (320) may include 1 wt% to 5 wt% of an isocyanate curing agent, as in Example 1-2. For example, the base coating layer (320) may include 1 wt% to 3 wt% of a melamine curing agent and 1 wt% to 3 wt% of an isocyanate curing agent, as in Example 1-3.

[0097] According to one embodiment, the base coating layer (320) may include at least one of an epoxy resin, a defoaming agent, a catalyst, an adhesion promoter, and an organic solvent. For example, the base coating layer (320) of Example 1-1, Example 1-2, or Example 1-3 of [Table 1] may include at least one of an epoxy resin, a defoaming agent, a catalyst, an adhesion promoter, and an organic solvent. For example, the base coating layer (320) may include 0 wt% to 3.0 wt% of an epoxy resin. For example, the base coating layer (320) may include 0.5 wt% to 1.0 wt% of a defoaming agent. For example, the base coating layer (320) may include 0 wt% to 1.0 wt% of an adhesion promoter to be strongly adhered to the steel plate (310). For example, the base coating layer (320) may contain 20 wt% to 30 wt% of an organic solvent.

[0098] According to one embodiment, the print layer (330) can be adhered onto the base coating layer (320) to maintain the printed color and pattern. A clear coating layer (350) is disposed on the print layer (330), so that the clear coating layer (350) can maintain the color and pattern printed on the print layer (330) clearly.

[0099] According to one embodiment, the print layer (330) may be formed using a digital printing method. The digital printing method can directly print a high-resolution image on a steel plate, and the process can be simplified compared to the printing method using a gravure roll, which is a conventional printing method. In addition, the digital printing method can precisely reproduce complex patterns, images, and / or text, and can be customized to various designs, so it can be advantageous for small-scale production. The digital printing method can provide a fast curing speed and excellent durability by using ink such as UV curing ink, for example. The print layer (330) formed using the digital printing method can maintain the printed design for a long time due to the strong adhesiveness with the base coating layer (320).

[0100] In one embodiment, the clear coating layer (350) can improve the appearance by imparting gloss to the surface. The clear coating layer (350) may be positioned to prevent damage to the print layer (330) from the outside. For example, the clear coating layer (350) may be positioned to protect the steel plate (310) and the print layer (330) from external environments such as physical damage, chemical corrosion, or ultraviolet rays. For example, the clear coating layer (350) may be a PET film layer.

[0101] According to one embodiment, the clear coating layer (350) may be composed of a polyester-based (PE) resin as a main raw material. According to one embodiment, the clear coating layer (350) may include acrylic and / or urethane.

[0102] Table 2 below exemplarily shows the composition ratio of some of the materials constituting the clear coating layer (350). The unit of each composition is weight %.

[0103] In addition to the materials shown in [Table 2], various materials may be added to the clear coating layer (350).

[0104] Example 2-1 Example 2-2 Example 2-3 Example 2-4 Example 2-5 Example 2-6 Polyester resin 60 ~ 75 60 35 ~ 40 60 35 ~ 40 60 ~ 75 Acrylic 00 5 ~ 10 10 ~ 15 10 ~ 15 0 Urethane 00 0 5 ~ 10 10 ~ 15

[0105] As described in [Table 2], the clear coating layer (350) may have a composition of one of Example 2-1, Example 2-2, Example 2-3, Example 2-4, Example 2-5, or Example 2-6, but this is exemplary, and the composition ratio of the clear coating layer (350) is not limited thereto.

[0106] In one embodiment, the clear coating layer (350) may include at least one of melamine, a leveling agent, a defoaming agent, a catalyst, an adhesion promoter, a wetting agent, and an organic solvent. For example, the clear coating layer (350) of Example 2-1, Example 2-2, Example 2-3, Example 2-4, Example 2-5, or Example 2-5 of [Table 2] may include at least one of melamine, a leveling agent, a defoaming agent, a catalyst, a wetting agent, and an organic solvent. For example, the clear coating layer (350) may include 0 wt% to 20 wt% of melamine. For example, the clear coating layer (350) may include 1.0 wt% to 2.0 wt% of the leveling agent. For example, the clear coating layer (350) may include 0.2 wt% to 0.5 wt% of the defoaming agent. For example, the clear coating layer (350) may include 0.5 wt% to 1.0 wt% of an adhesion promoter to be strongly adhered to the steel plate (310). For example, the clear coating layer (350) may include 1.0 wt% to 2.0 wt% of a wetting agent. For example, the clear coating layer (350) may include 15 wt% to 20 wt% of an organic solvent.

[0107] In one embodiment, the adhesive layer (340) may include, but is not limited to, an adhesive that cures rapidly through ultraviolet curing. The adhesive layer (340) may also be omitted from the configuration of the PCM steel plate (300).

[0108] Figures 4 and 5 are graphs showing the relationship between the gloss of the base coating layer and the gloss of the clear coating layer in the PCM steel plate of Figure 3.

[0109] [Table 3] is an experimental table comparing the gloss of the base coating layer and the gloss of the clear coating layer by changing the surface tension and degree of curing with respect to the specifications of the base coating layer (320) paint.

[0110] Here, gloss is measured by using a gloss meter to measure the amount of reflection when light is incident on the surface at a 20 degree angle.

[0111] The graphs in FIGS. 4 and 5 are graphs showing the correlation between the glossiness of the base coating layer and the glossiness of the clear coating layer, which are the experimental results of [Table 3]. The vertical axis of FIG. 4 represents glossiness. The horizontal axis of FIG. 5 represents glossiness of the base coating layer, and the vertical axis represents glossiness of the clear coating layer.

[0112] No. Surface tension (dyne) Hardness (MEK) Base coating gloss (GU) Clear coating gloss (GU) Existing 303758.076.4A-1305066.078.2A-2304062.077.4A-3304560.078.8B-1283578.079.3B-2602513.157.7B-36000.662.1C-1302057.080.7C-230543.577.6C-3301~26.868.4C-4302360.778.2C-530 3155.182.3C-63227.565.2C-7301653.079.0C-8301946.580.3D-1305550.984.0D-2305843.778.8D-33 04331.283.0D-4301745.984.2D-5301523.064.8D-6301955.375.1D-7304767.379.0D-83010070.879.5

[0113] Referring to FIGS. 4 and 5, it can be confirmed that the glossiness of the clear coating layer (350) is affected by the composition of the base coating layer (320) paint. Since an image is printed on the base coating layer (320) using a digital printing technique, the clarity of the image may vary depending on the physical properties of the base coating layer (320), and the glossiness of the clear coating layer (350) on the print layer (330) on which the image is printed may also vary due to the influence.

[0114] Based on the test examples illustrated in [Table 3], as shown in FIG. 5, the gloss of the clear coating layer (350) was compared according to the gloss of the base coating layer (320). As a result, it was experimentally confirmed that when the gloss of the base coating layer (320) is 30 or higher, the gloss of the clear coating layer can be 70 or higher. For example, as illustrated, when the gloss of the base coating layer (320) is 30.4 or higher, the gloss of the clear coating layer (350) can be 74.3 or higher.

[0115] According to one embodiment, the PCM steel plate (300) according to one embodiment can be manufactured so that the gloss of the base coating layer (320) is 30 GU or more, and the gloss of the clear coating layer (350) (or the surface of the PCM steel plate (300)) can be designed to be 70 GU or more.

[0116] Figures 6 and 7 are graphs showing the gloss and distinctness of image (DOI) of the clear coating layer according to the type of hardener and the addition ratio of the matting agent in the PCM steel plate of Figure 3.

[0117] FIGS. 6 and 7 are graphs showing the measurement of the gloss and clarity (or sharpness) of the clear coating layer (350) (or the surface of the PCM steel plate (300)) by controlling the type of hardener and the weight ratio of the matting agent (or surface tension control agent) included in the base coating layer (320). FIG. 6 is a graph showing the relationship between the gloss of the base coating layer (320) and the gloss of the clear coating layer (350) according to the type of hardener and the content of the matting agent included in the base coating layer (320). FIG. 7 is a graph showing the relationship between the gloss of the base coating layer (320) and the clarity of the clear coating layer (350) according to the type of hardener and the content of the matting agent included in the base coating layer (320).

[0118] In Figures 6 and 7, the horizontal axis may refer to a trial. M-0% is a base coating layer (320) containing a melamine hardener and 0 wt% of a matting agent, M-1% is a base coating layer (320) containing a melamine hardener and 1 wt% of a matting agent, M-2% is a base coating layer (320) containing a melamine hardener and 2 wt% of a matting agent, M-3% is a base coating layer (320) containing a melamine hardener and 3 wt% of a matting agent, M-4% is a base coating layer (320) containing a melamine hardener and 4 wt% of a matting agent, M-4.5% is a base coating layer (320) containing a melamine hardener and 4.5 wt% of a matting agent, M-5% is a base coating layer (320) containing a melamine hardener and 5 wt% of a matting agent, I-0% is a base coating layer (320) containing an isocyanate hardener and 0 wt% of a matting agent, I-1% is an isocyanate hardener and 1 A base coating layer (320) containing a matting agent of 1-2% by weight, a base coating layer (320) containing an isocyanate curing agent and 2% by weight of a matting agent, a base coating layer (320) containing an isocyanate curing agent and 3% by weight of a matting agent, a base coating layer (320) containing an isocyanate curing agent and 4% by weight of a matting agent, and a base coating layer (320) containing an isocyanate curing agent and 5% by weight of a matting agent were used.

[0119] In FIGS. 6 and 7, the vertical axis may represent gloss or depth of image (DOI).

[0120] Here, gloss is measured by using a gloss meter to measure the amount of reflection when light is incident on the surface at a 20 degree angle.

[0121] Here, sharpness is expressed as a number between 0 and 100, and a higher value means higher image clarity.

[0122] Here, the glossiness and clarity of the clear coating layer (350) may be the glossiness and clarity of the PCM steel plate (300) for home appliances.

[0123] [Table 4] is a table showing the values ​​of the gloss and clarity of the clear coating layer (350) (or the surface of the PCM steel plate (300)) measured by adjusting the type of hardener and the weight ratio of the matting agent among the materials included in the base coating layer (320).

[0124] In [Table 4], trials 1 to 7 used a melamine curing agent in the base coating layer (320), and trials 8 to 13 used an isocyanate curing agent in the base coating layer (320).

[0125] Trials 1 to 7 sequentially increased the content of a matting agent from 0% to 5% while using a melamine curing agent in the base coating layer (320). In Trials 1 to 7, the base coating layer (320) of Example 1-1 may be used, but is not limited thereto.

[0126] Trials 8 to 13 sequentially increased the content of a matting agent from 0% to 5% while using an isocyanate curing agent in the base coating layer (320). In Trials 8 to 13, the base coating layer (320) of Example 1-2 may be used, but is not limited thereto.

[0127] The clear coating layer (350) used in Trials 1 to 13 may be the clear coating layer (350) of Example 2-1, Example 2-2, Example 2-3, Example 2-4, Example 2-5, or Example 2-6, but is not limited thereto. For example, the glossiness and sharpness of the clear coating layer (350) may be improved by using the clear coating layer (350) of Example 2-4.

[0128] trial type of hardener content of matting agent surface tension (dyne) base coating layer gloss (GU) clear coating layer gloss (GU) clear coating layer Sunyoungseong1Melamine0%3073.383.37021%3265.176.16832%3243.074.26443%3424.560.16554%3817.158.06064.5%4416.855.65775%6018.059.3548Isocyanate0%3042.184.18891%3062.280.384102%3050.780.279113%3230.978.375124%4014.477.074135%6015.178.167

[0129] In order for the PCM steel plate (300) printed with an image using a digital printing method to have a high level of gloss and clarity like the VCM steel plate, the clarity of the image (DOI) of the clear coating layer (350) of the PCM steel plate (300) may be required to be 70 or higher.

[0130] Referring to the experimental values ​​in [Table 4], when the base coating layer (320) contains a melamine curing agent, it can be confirmed that the clarity of the clear coating layer (350) is 70 or higher only when the matting agent content is 0 wt%. In addition, when the base coating layer (320) contains an isocyanate curing agent, it can be confirmed that the clarity of the clear coating layer (350) is 70 or higher when the matting agent content is 0 wt% to 4 wt%. When the base coating layer (320) contains an isocyanate curing agent and the matting agent content exceeds 4 wt%, the clarity of the clear coating layer (350) may fall below 70, which may deteriorate the aesthetics of the PCM steel plate (300).

[0131] According to one embodiment, the base coating layer (320) included in the PCM steel sheet (300) having high gloss and high contrast may include a melamine curing agent and 0 wt% of a matting agent. When the base coating layer (320) includes a melamine curing agent, the addition of the matting agent may lower the contrast of the clear coating layer (350) to less than 70. In the case of the melamine curing agent, water is generated by a condensation reaction during the reaction, which may affect the printing of the print layer (330) and may also affect the surface condition of the clear coating layer (350) by lowering the gloss or contrast.

[0132] According to one embodiment, the base coating layer (320) included in the PCM steel sheet (300) having high gloss and high contrast may include an isocyanate curing agent and 0 to 4 wt% of a matting agent. When the base coating layer (320) includes an isocyanate curing agent, if the matting agent content exceeds 4 wt%, the contrast of the clear coating layer (350) may be lowered to less than 70.

[0133] According to one embodiment, the gloss of the base coating layer (320) included in the PCM steel sheet (300) having high gloss and high contrast may be 30 GU or more. Referring to the experimental values ​​in [Table 4], it can be confirmed that when the gloss of the base coating layer (320) is 30 GU or more, the clarity of the clear coating layer (350) is 70 or more. Therefore, in order to have high gloss and high contrast, the gloss of the base coating layer (320) may be 30 GU or more.

[0134] Fig. 8 is an experimental example to explain the clarity of the print layer according to the ratio of the matting agent added to the base coating layer in the PCM steel plate of Fig. 3.

[0135] Figure 8 (a) shows the experimental results of printing an image on the upper surface by digital printing without adding a matting agent to the base coating layer (320), Figure 8 (b) shows the experimental results of printing an image on the upper surface by digital printing with 2 wt% of a matting agent added to the base coating layer (320), and Figure 8 (c) shows the experimental results of printing an image on the upper surface by digital printing with 4 wt% of a matting agent added to the base coating layer (320).

[0136] Figures 8 (a), (b), and (c) are experimental examples, and the scope of the present disclosure is not limited thereto.

[0137] The clarity of the print layer (330) printed on the base coating layer (320) by digital printing may be affected by the surface tension of the base coating layer (320). If the surface tension of the ink used for digital printing is excessively lower than the surface tension of the base coating layer (320), the ink may spread, blurring the image to be printed and reducing the clarity. If the surface tension of the ink used for digital printing is excessively higher than the surface tension of the base coating layer (320), the ink may clump together, generating a crater (e.g., 810, 820). Here, the crater may refer to a portion where the ink clumps together and the surface of the base coating layer (320) is exposed to the outside. Therefore, in order to minimize the formation of craters and improve the clarity of the image, it is necessary to add an appropriate amount of a matting agent (or surface tension control agent) to the base coating layer (320).

[0138] According to one embodiment, as shown in (a) of FIG. 8, when a matting agent is not added to the surface of the base coating layer (320), a large number of craters (810) may be formed between the printed images.

[0139] According to one embodiment, as shown in (b) of FIG. 8, when 2 wt% of a matting agent is added to the surface of the base coating layer (320), a relatively small number of craters (820) can be formed compared to (a) of FIG. 8.

[0140] According to one embodiment, as shown in (c) of FIG. 8, when 4 wt% of a matting agent is added to the surface of the base coating layer (320), the ink used in digital printing may be properly spread, thereby preventing the formation of craters.

[0141] If a matting agent exceeding 4 wt% is added to the surface of the base coating layer (320), the image to be printed may become blurred due to ink spreading, thereby reducing clarity. Therefore, to improve clarity, the content of the matting agent added to the base coating layer (320) may be 0 wt% to 4 wt% or less. For example, the content of the matting agent added to the base coating layer (320) may be more than 2 wt% and less than 4 wt%.

[0142] According to one embodiment, the surface tension of the base coating layer (320) may be 30 dyne to 60 dyne to minimize the formation of craters (e.g., 810, 820) and to minimize blurring of the image to be printed by digital printing.

[0143] According to one embodiment of the present disclosure, the PCM steel plate (300) can secure printability of digital printing by adjusting the composition and properties of the base coating layer (320), thereby obtaining a high-quality exterior design.

[0144] The PCM steel plate (300) according to one embodiment of the present disclosure can print all colors and patterns at once by digital printing, so that it is not necessary to produce as many silkscreen or gravure printing rolls as there are colors and patterns, thereby saving the cost and time required for production.

[0145] A PCM steel plate (300) according to one embodiment of the present disclosure may include a base coating layer (320) suitable for a digital printing method to improve overall gloss and clarity (or sharpness) by printing colors and patterns using a digital printing method.

[0146] FIG. 9 is a cross-sectional view of a PCM steel plate for home appliances according to one embodiment of the present disclosure.

[0147] FIG. 10 is a cross-sectional view of a PCM steel plate for home appliances according to one embodiment of the present disclosure.

[0148] Fig. 11 is a cross-sectional view of a PCM steel plate for home appliances according to one embodiment of the present disclosure.

[0149] The embodiments of FIGS. 9 to 11 can be optionally combined with the embodiment of FIG. 3.

[0150] The PCM steel plate (300-1) of FIG. 9, the PCM steel plate (300-2) of FIG. 10, and the PCM steel plate (300-3) of FIG. 11 can constitute at least a part of the outer case (e.g., the outer case (11) of FIG. 2), the inner case (e.g., the inner case (12) of FIG. 2), and the door (e.g., the door (30) of FIG. 2) of the refrigerator (1) of FIG. 1 and FIG. 2.

[0151] The configuration of the PCM steel plates (300-1, 300-2, 300-3) of FIGS. 9 to 11 may be all or part of the same as the configuration of the PCM steel plate (300) of FIG. 3.

[0152] Referring to FIGS. 9 to 11, a PCM steel plate (300-1, 300-2, 300-3) according to one embodiment may include a steel plate (310), a Mars treatment layer (360), a base coating layer (320), a print layer (330), an adhesive layer (340), and a film layer (370).

[0153] According to one embodiment, the plated steel sheet (310) may include an electrolytic galvanized iron (EGI) steel sheet or a galvanized iron (GI) steel sheet.

[0154] According to one embodiment, the base coating layer (320) may be disposed on the steel plate (310). The base coating layer (320) may have various colors and / or patterns so as to impart various colors and / or patterns to the PCM steel plates (300-1, 300-2, 300-3). For example, the base coating layer (320) may have a white color that is difficult to implement with ink used for digital inkjet printing of the print layer (330). The base coating layer (320) may include at least one of a polyester resin, an auxiliary resin, a curing resin, or a matting agent.

[0155] According to one embodiment, the print layer (330) may be disposed on the steel plate (310). The print layer (330) may have various colors, patterns, and / or images by a digital inkjet printing method so as to impart various colors, patterns, and / or images to the PCM steel plates (300-1, 300-2, 300-3). The print layer (330) may be formed by, for example, pattern printing ink composed of C (Cyan), M (Magenta), Y (Yellow), and K (Black) colors through a digital inkjet printer and then curing the ink. The ink used in the digital inkjet printing may include UV ink that is cured by ultraviolet rays.

[0156] According to one embodiment, the adhesive layer (340) may be disposed on the print layer (330). The adhesive layer (340) may be provided to attach the film layer (370) to the print layer (330). The adhesive layer (340) may include, for example, a thermosetting adhesive or a UV adhesive. The print layer (330) formed through digital inkjet printing may include a step difference according to a height difference in each region. When attaching (or laminating) the film layer (370) to the PCM steel plates (300-1, 300-2, 300-3), a UV adhesive may be used to remove the step difference of the print layer (330).

[0157] According to one embodiment, the chemical treatment layer (360) may be disposed on the steel plate (310). The chemical treatment layer (360) may be disposed between the steel plate (310) and the base coating layer (320). The chemical treatment layer (360) may be subjected to a chemical conversion treatment on the steel plate (310) to secure corrosion resistance and interlayer adhesion of the steel plate (310) after a degreasing and rinsing process of the steel plate (310). For example, the chemical treatment layer (360) may be provided in the form of a chemical conversion film by a process such as a phosphate treatment or a chromate treatment.

[0158] According to one embodiment, a film layer (370) may be disposed on the print layer (330). The film layer (370) may be provided to impart gloss to the PCM steel plates (300-1, 300-2, 300-3) or to protect the print layer (330) from the outside. The film layer (370) may include a PET (polyethylene terephthalate) film. The film layer (370) may include, for example, a PET film with a glossy or matte finish. The film layer (370) may further include, for example, a hard coating layer (380) with a glossy or matte finish to ensure scratch resistance, as illustrated in FIG. 10. The film layer (370) may further include a pattern layer (390) having a three-dimensional pattern, which is formed through imprinting to impart a three-dimensional effect, as illustrated in FIG. 11.

[0159] In the case of a film layer (370) such as a PET film, a film shrinkage phenomenon may occur during the process of attaching (or laminating) the film to the steel plate (310). When the film shrinkage phenomenon occurs, peeling may occur in a portion of the layers constituting the PCM steel plate (300-1, 300-2, 300-3) where the interlayer adhesion is weak. For example, the thermosetting base coating layer (320) and the UV-curable print layer (330) have the weakest interlayer adhesion due to their different curing methods, and thus, interlayer peeling may occur between the base coating layer (320) and the print (330). Therefore, it is important for the digital printing PCM steel plate (300-1, 300-2, 300-3) using a film (e.g., PET film) to secure interlayer adhesion between the base coating layer (320) and the print layer (330).

[0160] Hereinafter, the composition of the base coating layer (320) for securing interlayer adhesion between the base coating layer (320) and the print layer (330) will be described.

[0161]

[0162] According to one embodiment, the base coating layer (320) may include an auxiliary resin having a structural formula as shown in the above [Chemical Formula 1]. The auxiliary resin may be capable of both thermal curing and UV curing. Referring to part A of [Chemical Formula 1], the auxiliary resin may include an acrylate having a double bond and a functional group (or, functional group). For example, the auxiliary resin may include polyester acrylate, urethane acrylate, or epoxy acrylate. The auxiliary resin may be UV cured through the double bond of the acrylate capable of UV radical reaction. For example, the auxiliary resin may be chemically bonded to the ink of the print layer (330) through the acrylate. Referring to part B of [Chemical Formula 1], the auxiliary resin may include a -OH group (or, hydroxyl group, hydroxyl group). The auxiliary resin may be thermally cured through the -OH group capable of thermal curing reaction. For example, the auxiliary resin may be chemically bonded to the curing resin (e.g., melamine and / or isocyanate, which will be described later) of the base coating layer (320) via the -OH group. In this way, the auxiliary resin has a heat-curable and VU-curable property, and thus may form a chemical bond with the UV ink of the print layer (330), thereby improving the interlayer adhesion between the base coating layer (320) and the print layer (330). The auxiliary resin may be called a dual resin or a dual cure resin.

[0163] Print layer thickness (um) Processing properties Auxiliary resin content (wt%) 0 wt% 0.5 wt% 1.0 wt% 1.5 wt% 2.0 wt% 2.5 wt% 3.0 wt% 3.5 wt% 4.0 wt% Below 10 um Room temperature peeling Good Good Good Good Good Good Good Good Good High temperature and high humidity peeling Good Good Good Good Good Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Peeling Printability Good Good Good Good Good Print Dry Print Dry Print Dry Print Dry

[0164] [Table 5] is a table showing the interlayer adhesion (or processing adhesion) and printability according to the content of auxiliary resin.

[0165] Referring to [Table 5], in the case of the PCM steel plate (300-1, 300-2, 300-3) according to one embodiment, when the thickness of the print layer (330) is 10 μm or less, it can be confirmed that peeling occurred between the base coating layer (320) and the print layer (330) when the content of the auxiliary resin was 0 wt% relative to the weight of the entire composition constituting the base coating layer (320) under room temperature (e.g., 21 to 23°C). On the other hand, when the content of the auxiliary resin was 0.5 wt% to 4.0 wt% relative to the weight of the entire composition constituting the base coating layer (320), it can be confirmed that peeling did not occur between the base coating layer (320) and the print layer (330) and interlayer adhesion was secured.

[0166] According to one embodiment, in the case of the PCM steel plate (300-1, 300-2, 300-3) having a thickness of the print layer (330) of 10 μm or less, it can be confirmed that peeling occurs between the base coating layer (320) and the print layer (330) when the content of the auxiliary resin is 0 wt% and 3.0 wt% to 4.0 wt% relative to the weight of the entire composition constituting the base coating layer (320) under high temperature (e.g., 65° C. or higher) and high humidity (e.g., 95% or higher) conditions. On the other hand, in the case where the content of the auxiliary resin is 0.5 wt% to 2.5 wt% relative to the weight of the entire composition constituting the base coating layer (320), it can be confirmed that peeling does not occur between the base coating layer (320) and the print layer (330) and that interlayer adhesion is secured.

[0167] According to one embodiment, in the case where the thickness of the print layer (330) is 10 μm or more, it can be confirmed that peeling occurs between the base coating layer (320) and the print layer (330) under room temperature conditions when the content of the auxiliary resin is 0 wt% relative to the weight of the entire composition constituting the base coating layer (320). On the other hand, when the content of the auxiliary resin is 0.5 wt% to 4.0 wt% relative to the weight of the entire composition constituting the base coating layer (320), it can be confirmed that peeling does not occur between the base coating layer (320) and the print layer (330) and interlayer adhesion is secured.

[0168] According to one embodiment, in the case of the PCM steel plate (300-1, 300-2, 300-3) having a thickness of the print layer (330) of 10 μm or more, it can be confirmed that peeling occurs between the base coating layer (320) and the print layer (330) under high temperature and high humidity conditions when the content of the auxiliary resin is 0 wt% to 4.0 wt% relative to the weight of the entire composition constituting the base coating layer (320).

[0169] In addition, referring to [Table 5], it can be confirmed that as the content of the auxiliary resin increases, the printability of the print layer (330) gradually decreases.

[0170] As a result, when applying the auxiliary resin to the base coating layer (320), there is no problem with interlayer adhesion under room temperature conditions, but when the thickness of the print layer (330) is 10 μm or more, it can be confirmed that interlayer adhesion is not secured under high temperature and high humidity conditions. Accordingly, a method is required to additionally secure interlayer adhesion within the content range of the auxiliary resin that satisfies printability (e.g., 1.0 wt% to 1.5 wt%).

[0171] Hereinafter, a method for improving the physical bonding strength between layers as a means for securing interlayer adhesion within the content range of the auxiliary resin (e.g., 1.0 wt% to 1.5 wt%) is described.

[0172] Print layer thickness (um) Processing properties Melamine / Isocyanate ratio 100 / 0.90 / 10.80 / 20.70 / 30.60 / 40.50 / 50.40 / 60.30 / 70.20 / 80.10 / 900 / 100.10um or more Room temperature Good Good Good Good Good Good Good Good Good Good Good Good Good High temperature and high humidity Peeling Peeling Peeling Peeling Peeling Peeling Fine Peeling Ultra-fine Peeling Ultra-fine Peeling Fine Peeling Peeling Peeling Printability Good Good Good Good Good Good Good Good Good Good Good Print drying Print drying MEK Test Rubbing count 100 times or more 100 times or more 80~90 times 60~70 times 60~70 times 40~50 times 30~40 times 20~30 times 20~30 times 10~15 times 10 times or less

[0173] [Table 6] is a table showing the results of interlayer adhesion (or processing adhesion), printability, and MEK (methylethylketone) Rubbing tests according to the ratio of the cured resin included in the base coating layer (320). [Table 6] includes data values ​​measured when the content of the auxiliary resin is 1.0 wt% to 1.5 wt% and the content of the cured resin is 4 wt% to 10 wt%.

[0174] Referring to the above [Table 6], the base coating layer (320) according to one embodiment may include melamine resin and isocyanate as a curing resin.

[0175] According to one embodiment, it can be confirmed that the PCM steel plate (300-1, 300-2, 300-3) has interlayer adhesion secured across the entire ratio of melamine resin and isocyanate resin under room temperature conditions when the thickness of the print layer (330) is 10 μm or more.

[0176] According to one embodiment, it can be confirmed that the degree of peeling of the PCM steel plate (300-1, 300-2, 300-3) is different for each predetermined content across the ratio of melamine resin and isocyanate resin under high temperature and high humidity conditions when the thickness of the print layer (330) is 10 μm or more.

[0177] For example, when the ratio of melamine resin and isocyanate resin is 100:0 to 50:50 and 0:100, it can be confirmed that complete peeling occurred between the base coating layer (320) and the print layer (330).

[0178] For example, when the ratio of melamine resin and isocyanate resin is 40:60 and 10:90, it can be confirmed that fine peeling occurred between the base coating layer (320) and the print layer (330).

[0179] For example, when the ratio of melamine resin and isocyanate resin is 30:70 to 20:80, it can be confirmed that almost no peeling occurred between the base coating layer (320) and the print layer (330).

[0180] This is a result caused by the fact that melamine resin has a three-dimensional structure, whereas isocyanate has a linear structure. Specifically, when the proportion of isocyanate in the total content of melamine resin and isocyanate increases, the surface hardness of the base coating layer (330) decreases, and the surface area per unit area where the ink of the print layer (330) and the base coating layer (320) come into contact increases, thereby improving the physical bonding force. For example, looking at the MEK test results in [Table 6], it can be confirmed that as the proportion of isocyanate in the total content of melamine resin and isocyanate increases, the number of rubbings gradually decreases (i.e., the surface hardness decreases).

[0181] In addition, referring to [Table 6], it can be confirmed that when the proportion of isocyanate increases in the ratio of melamine resin and isocyanate resin, the printability of the print layer (330) gradually deteriorates.

[0182] Consequently, when the proportion of isocyanate in the total content of melamine resin and isocyanate resin increases, interlayer adhesion can be improved or secured within a certain range. For example, the base coating layer (320) may include melamine resin and isocyanate resin in a ratio of 30 to 70 to 20 to 80.

[0183] Print layer thickness (um) Processing properties Matting agent content 0 wt% 0.5 wt% 1.0 wt% 1.5 wt% 2.0 wt% 2.5 wt% 3.0 wt% 3.5 wt% 10 um or more Room temperature Good Good Good Good Good Good Good Good Good High temperature High humidity Extremely fine peeling Extremely fine peeling Good Good Good Fine peeling Fine peeling Fine peeling Printability Good Good Good Good Good Print drying Print drying Print drying

[0184] [Table 7] is a table showing interlayer adhesion (or processing adhesion) and printability according to the content of the matting agent. [Table 7] includes data values ​​measured when the content of the auxiliary resin is 1.0 wt% to 1.5 wt% and the content of the curing resin is 4 wt% to 10 wt% (melamine resin:isocyanate = 20:80).

[0185] Referring to [Table 7], the base coating layer (320) according to one embodiment may include a matting agent. The matting agent may impart surface roughness (roughness) to the base coating layer (320). For example, the matting agent may form unevenness on the surface of the base coating layer (320), thereby increasing the surface area per unit area. The matting agent may include, for example, silica, but the present disclosure is not limited thereto.

[0186] According to one embodiment, it can be confirmed that when the thickness of the print layer (330) is 10 μm or more, the PCM steel plate (300-1, 300-2, 300-3) does not cause peeling between the base coating layer (320) and the print layer (330) and the content of the matting agent is in the range of 0 wt% to 3.5 wt% under room temperature conditions, and interlayer adhesion is secured.

[0187] According to one embodiment, it can be confirmed that the degree of peeling of the PCM steel plate (300-1, 300-2, 300-3) varies depending on the content of the matting agent under high temperature and high humidity conditions when the thickness of the print layer (330) is 10 um or more.

[0188] For example, when the content of the matting agent is in the range of 0 wt% to 0.5 wt%, it can be confirmed that almost no peeling occurs between the base coating layer (320) and the print layer (330).

[0189] For example, when the content of the matting agent is in the range of 1.0 wt% to 2.0 wt%, it can be confirmed that almost no peeling occurs between the base coating layer (320) and the print layer (330), and interlayer adhesion is secured.

[0190] For example, when the content of the matting agent is in the range of 2.5 wt% to 3.5 wt%, it can be confirmed that fine peeling occurs between the base coating layer (320) and the print layer (330).

[0191] In addition, referring to [Table 7], it can be confirmed that as the content of the quencher increases, the printability of the print layer (330) gradually deteriorates.

[0192] Consequently, when a matting agent is included in the base coating layer (320), interlayer adhesion can be improved or secured even under high temperature and high humidity conditions within a certain range. For example, the base coating layer (320) can include a matting agent having 1.0 wt% to 2.0 wt%.

[0193] Gravure Printing Digital Printing Digital Printing Clear Layer Film Clear Layer Film Gloss (Gloos 20°) 90~95 115~120 75~80 115~120 Line of Sight (DOI) 75~78 86~89 30~33 98~99 Reflective Image Quality (RIQ) 62~67 67~72 10~15 91~95

[0194] [Table 8] shows the gloss, clarity, and reflection image quality of PCM steel sheets produced using gravure printing and inkjet printing, depending on the manufacturing method (clear layer or film layer). The data values ​​in [Table 8] were measured using a Rhopoint IQ optical system.

[0195] Referring to [Table 8], the PCM steel sheets (300-1, 300-2, 300-3) having the aforementioned film layer (370) can have gloss, clarity, and / or reflective image quality similar to or better than that of a PCM steel sheet using a gravure printing method. In addition, the PCM steel sheets (300-1, 300-2, 300-3) can have gloss, clarity, and / or reflective image quality better than that of a PCM steel sheet using a digital printing method using a clear layer (350). For example, the PCM steel sheets (300-1, 300-2, 300-3) can have gloss of 115 to 120 GU, clarity of 98 to 99, and / or reflective image quality of 91 to 95.

[0196] A PCM steel plate (300) for a home appliance according to one embodiment may include a steel plate (310), a base coating layer (320) disposed on the steel plate (310) and including at least one of a melamine curing agent and an isocyanate curing agent, a print layer (330) disposed on the base coating layer (320), and a clear coating layer (350) disposed on the print layer (330). The base coating layer (320) may include 0 wt% to 10 wt% of a matting agent.

[0197] According to one embodiment, the base coating layer (320) may include 1 wt% to 5 wt% of a melamine curing agent.

[0198] According to one embodiment, the base coating layer (320) may include 1 wt% to 5 wt% of an isocyanate curing agent.

[0199] According to one embodiment, the base coating layer (320) may include 1 wt% to 3 wt% of a melamine curing agent and 1 wt% to 3 wt% of an isocyanate curing agent.

[0200] According to one embodiment, the surface tension of the base coating layer (320) may be 30 dyne to 60 dyne.

[0201] According to one embodiment, the base coating layer (320) may include 0 wt% to 4 wt% of a matting agent.

[0202] According to one embodiment, the print layer (330) can be printed using a digital printing method.

[0203] According to one embodiment, the 20 degree gloss of the base coating layer (320) may be 30 GU or more.

[0204] According to one embodiment, the 20-degree gloss of the clear coating layer (350) affected by the 20-degree gloss of the base coating layer (320) may be 70 GU or more.

[0205] According to one embodiment, the degree of sharpness (DOI) of the clear coating layer (350) affected by the 20 degree gloss of the base coating layer (320) may be 70 or more.

[0206] According to one embodiment, a refrigerator may include a main body (10), a storage compartment (13) provided inside the main body (10), and a door (30) coupled to the main body (10) to open and close at least a portion of the storage compartment (13). The door (30) may include a PCM steel plate (300). The PCM steel plate (300) may include a steel plate (310), a base coating layer (320) disposed on the steel plate (310) and including at least one of a melamine curing agent and an isocyanate curing agent, a print layer (330) disposed on the base coating layer (320), and a clear coating layer (350) disposed on the print layer (330). The base coating layer (320) may include 0 wt% to 10 wt% of a matting agent.

[0207] According to one embodiment, the base coating layer (320) may include 1 wt% to 5 wt% of a melamine curing agent.

[0208] According to one embodiment, the base coating layer (320) may include 1 wt% to 5 wt% of an isocyanate curing agent.

[0209] According to one embodiment, the base coating layer (320) may include 1 wt% to 3 wt% of a melamine curing agent and 1 wt% to 3 wt% of an isocyanate curing agent.

[0210] According to one embodiment, the surface tension of the base coating layer (320) may be 30 dyne to 60 dyne.

[0211] According to one embodiment, the base coating layer (320) may include 0 wt% to 4 wt% of a matting agent.

[0212] According to one embodiment, the print layer (330) can be printed using a digital printing method.

[0213] According to one embodiment, the 20 degree gloss of the base coating layer (320) may be 30 GU or more.

[0214] According to one embodiment, the 20-degree gloss of the clear coating layer (350) affected by the 20-degree gloss of the base coating layer (320) may be 70 GU or more.

[0215] According to one embodiment, the degree of sharpness (DOI) of the clear coating layer (350) affected by the 20 degree gloss of the base coating layer (320) may be 70 or more.

[0216] According to one embodiment, a PCM steel plate (300-1, 300-2, 300-3) for a home appliance may include a steel plate (310), a base coating layer (320) disposed on the steel plate (310) and including a cured resin, a print layer (330) disposed on the base coating layer (320) and including UV ink, and a film layer (370) disposed on the print layer (330). The base coating layer (320) may include an auxiliary resin chemically bondable with the cured resin and the UV ink. The auxiliary resin may be present in an amount of 1.0 to 1.5 wt% based on the total weight of the base coating layer (320).

[0217] According to one embodiment, the cured resin of the base coating layer (320) may include melamine resin and isocyanate resin.

[0218] According to one embodiment, the cured resin may be present in an amount of 4 to 10 wt% based on the total weight of the base coating layer (320).

[0219] According to one embodiment, the ratio of the melamine resin and the isocyanate resin may be 30:70 to 20:80.

[0220] According to one embodiment, the base coating layer (320) may include a matting agent in an amount of 1.0 to 2.0 wt% based on the total weight of the base coating layer (320).

[0221] In one embodiment, the matting agent may include silica.

[0222] According to one embodiment, the 20 degree gloss of the film layer (370) may be 115 to 120 GU, and the sharpness of the film layer (370) may be 98 to 99.

[0223] According to one embodiment, the film layer (370) may include a PET film with a glossy or matte finish.

[0224] According to one embodiment, the film layer (370) may further include a glossy or matte hard coating layer (380) or an imprinted pattern layer (390).

[0225] According to one embodiment, the print layer (330) can be printed using a digital printing method.

[0226] A refrigerator (1) according to one embodiment may include a main body (10), a storage compartment (13) provided inside the main body (10), and a door (30) coupled to the main body (10) to open and close at least a portion of the storage compartment (13). The door (30) may include a PCM steel plate (300-1, 300-2, 300-3). The PCM steel plate (300-1, 300-2, 300-3) may include a steel plate (310), a base coating layer (320) disposed on the steel plate (310) and including a cured resin, a print layer (330) disposed on the base coating layer (320) and including UV ink, and a film layer (370) disposed on the print layer (330). The base coating layer (320) may include an auxiliary resin chemically bondable to the cured resin and the UV ink.

[0227] Although the foregoing description in this disclosure has focused on specific embodiments, it should be understood that this disclosure is not limited to such specific embodiments, but rather encompasses various modifications, equivalents, and / or alternatives of the various embodiments.

Claims

1. In PCM steel plates for home appliances (300-1, 300-2, 300-3), Steel plate (310); A base coating layer (320) disposed on the above steel plate (310) and containing a cured resin; A print layer (330) disposed on the base coating layer (320) and containing UV ink; and It includes a film layer (370) placed on the above print layer (330), The above base coating layer (320) includes an auxiliary resin that can be chemically bonded with the cured resin and the UV ink, The above auxiliary resin is a PCM steel plate, which is 1.0 to 1.5 wt% based on the total weight of the base coating layer (320).

2. In paragraph 1, The cured resin of the above base coating layer (320) is a PCM steel plate including melamine resin and isocyanate resin.

3. In paragraph 2, The above-mentioned cured resin is a PCM steel plate, which is 4 to 10 wt% based on the total weight of the base coating layer (320).

4. In any one of paragraphs 2 to 3, PCM steel sheet having a ratio of the above melamine resin and isocyanate resin of 30:70 to 20:

80.

5. In any one of paragraphs 1 to 4, The base coating layer (320) is a PCM steel sheet containing a matting agent in an amount of 1.0 to 2.0 wt% based on the total weight of the base coating layer (320).

6. In paragraph 5, The above-mentioned matting agent is a PCM steel plate containing silica.

7. In any one of paragraphs 1 to 6, The 20 degree gloss of the above film layer (370) is 115 to 120 GU, PCM steel plate having a sharpness of the above film layer (370) of 98 to 99.

8. In any one of paragraphs 1 to 7, The above film layer (370) is a PCM steel plate including a PET film with a glossy or matte finish.

9. In any one of paragraphs 1 to 8, The above film layer (370) further includes a hard coating layer (380) with a glossy or matte finish or an imprinted pattern layer (390), a PCM steel plate.

10. In any one of paragraphs 1 to 9, The above print layer (330) is a PCM steel plate printed using a digital printing method.

11. In the refrigerator (1), Body (10); A storage room (13) provided inside the main body (10); and It includes a door (30) coupled to the main body (10) to open and close at least a part of the storage room (13), The above door (30) includes PCM steel plate (300-1, 300-2, 300-3), The above PCM steel plates (300-1, 300-2, 300-3) are Steel plate (310) A base coating layer (320) disposed on the above steel plate (310) and containing a cured resin; A print layer (330) disposed on the base coating layer (320) and containing UV ink; and It includes a film layer (370) placed on the above print layer (330), The above base coating layer (320) includes an auxiliary resin that can be chemically bonded with the cured resin and the UV ink, A refrigerator in which the auxiliary resin is 1.0 to 1.5 wt% based on the total weight of the base coating layer (320).

12. In paragraph 11, The cured resin of the above base coating layer (320) is a refrigerator including melamine resin and isocyanate resin.

13. In paragraph 12, A refrigerator in which the above-mentioned cured resin is 4 to 10 wt% based on the total weight of the base coating layer (320).

14. In paragraph 12 or 13, A refrigerator in which the ratio of the melamine resin and the isocyanate resin is 30:70 to 20:

80.

15. In any one of paragraphs 11 to 14, A refrigerator in which the base coating layer (320) contains a matting agent in an amount of 1.0 to 2.0 wt% based on the total weight of the base coating layer (320).

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