PCM steel sheet for home appliances and washing machine comprising same

Abstract

A PCM steel sheet for home appliances according to an embodiment of the present disclosure may comprise: a steel sheet; a chemical conversion treatment layer disposed on the steel sheet; a primer disposed on the chemical conversion treatment layer; a base coating layer disposed on the primer and containing a pigment; a print layer disposed on the base coating layer; and a clear coating layer disposed on the print layer and containing a polyester resin. The polyester resin may have an average molecular weight (Mw) of 8000 to 12000.

Description

PCM steel sheet for home appliances and washing machines containing the same

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

[0002] Home appliances like washing machines may incorporate steel sheets to achieve 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] The above information may be provided as background art to aid in understanding the present disclosure. No claim or determination is made as to whether any of the above is applicable as prior art related to the present disclosure.

[0004] Various embodiments of the present disclosure can implement high gloss, high contrast, or high brightness at the level of VCM steel sheets by introducing a digital printing method and controlling the composition of the coating layer.

[0005] A PCM steel sheet for home appliances according to one embodiment of the present disclosure may include a steel sheet, a chemical treatment layer disposed on the steel sheet, a primer disposed on the chemical treatment layer, a base coating layer disposed on the primer and including a pigment, a print layer disposed on the base coating layer, and a clear coating layer disposed on the print layer and including a polyester resin. The average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0006] According to one embodiment of the present disclosure, a washing machine may include a casing including a plurality of panels, a tub disposed within the casing, and a drum rotatably disposed within the tub. The plurality of panels may include a PCM steel plate. The PCM steel plate may include a steel plate, a chemical treatment layer disposed on the steel plate, a primer disposed on the chemical treatment layer, a base coating layer disposed on the primer and including a pigment, a print layer disposed on the base coating layer, and a clear coating layer disposed on the print layer and including a polyester resin. The average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0007] However, the problem to be solved in this disclosure is not limited to the problem mentioned above, and may be determined in various ways without departing from the spirit and scope of this disclosure.

[0008] Figure 1 is a perspective view of a washing machine according to one embodiment.

[0009] Figure 2 is a cross-sectional view of a washing machine according to one embodiment.

[0010] FIG. 3 is a schematic diagram illustrating a PCM steel plate for home appliances according to one embodiment.

[0011] FIG. 4 is a graph showing the gloss, processability, and hardness according to the molecular weight of the polyester resin of the clear coating layer according to one embodiment of the present disclosure.

[0012] FIG. 5 is a graph showing the clarity and brightness according to particle size and content of aluminum paste, which is a metallic pigment of a base coating layer according to one embodiment of the present disclosure.

[0013] FIG. 6 is a graph showing the clarity and brightness according to particle size and content of aluminum paste, which is a metallic pigment of a base coating layer according to one embodiment of the present disclosure.

[0014] FIG. 7 is a graph showing the gloss, clarity, and brightness according to particle size and particle shape of an aluminum paste according to one embodiment of the present disclosure.

[0015] The following description refers to the attached drawings, 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.

[0016] 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 to encompass various modifications, equivalents, or substitutes of the embodiments.

[0017] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0018] 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.

[0019] 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.

[0020] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0021] 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).

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] According to various embodiments, home appliances may include a clothing treatment device. A washing machine, one such clothing treatment device, can perform washing, rinsing, dehydration, and drying processes. A washing machine is an example of a clothing treatment device, and the term "clothing treatment device" encompasses devices that wash clothing (laundry items, drying items), devices that dry clothing, and devices capable of both washing and drying clothing.

[0027] Washing machines according to various embodiments may include top-loading washing machines in which the laundry inlet for loading or removing laundry is provided facing upward, or front-loading washing machines in which the laundry inlet is provided facing forward. Washing machines according to various embodiments may include washing machines of other loading methods other than top-loading washing machines and front-loading washing machines.

[0028] In the case of a top-loading washing machine, laundry can be washed using a water current generated by a rotating body such as a pulsator. In the case of a front-loading washing machine, laundry can be washed by rotating the drum to repeatedly raise and lower the laundry. The front-loading washing machine may include a washing machine with a dryer that can dry the laundry contained inside the drum. The washing machine with a dryer may include a hot air supply device for supplying high-temperature air into the drum and a condensing device for removing moisture from the air discharged from the drum. For example, the washing machine with a dryer may include a heat pump device. The washing machine according to various embodiments may include a washing machine with a washing method other than the washing method described above.

[0029] Washing machines according to various embodiments may include a housing that accommodates various components therein. The housing may be provided in the form of a box with a laundry inlet formed on one side.

[0030] A washing machine may include a door for opening and closing the laundry compartment. The door may be rotatably mounted to the housing by a hinge. At least a portion of the door may be transparent or translucent to allow the interior of the housing to be viewed.

[0031] A washing machine may include a tub provided within a housing to store water. The tub may be provided in a generally cylindrical shape with a tub opening formed on one side, and may be positioned within the housing such that the tub opening corresponds to a laundry inlet.

[0032] The tub may be connected to the housing by a damper. The damper can absorb vibrations generated when the drum rotates, thereby reducing the vibrations transmitted to the housing.

[0033] A washing machine may include a drum configured to accommodate laundry.

[0034] The drum may be positioned within the tub such that the drum opening provided on one side corresponds to the laundry inlet and the tub opening. Laundry may be sequentially passed through the laundry inlet, the tub opening, and the drum opening to be accommodated within the drum or taken out from the drum.

[0035] The drum rotates within the tub and can perform each of the washing, rinsing, and / or dehydration operations. The cylindrical wall of the drum is formed with a number of perforations, allowing water stored in the tub to flow into or out of the drum.

[0036] A washing machine may include a drive device configured to rotate a drum. The drive device may include a drive motor and a rotating shaft for transmitting driving force generated by the drive motor to the drum. The rotating shaft may be connected to the drum by penetrating the tub.

[0037] The driving device can rotate the drum forward or backward to perform each operation according to the washing, rinsing, and / or dehydration, or drying cycle.

[0038] A washing machine may include a water supply device configured to supply water to a tub. The water supply device may include a water supply pipe and a water supply valve provided on the water supply pipe. The water supply pipe may be connected to an external water source. The water supply pipe may extend from the external water source to a detergent supply device and / or the tub. Water may be supplied to the tub via the detergent supply device. Water may be supplied to the tub without passing through the detergent supply device.

[0039] The water supply valve can open or close the water supply pipe in response to an electrical signal from the control unit. The water supply valve can allow or block the supply of water to the tub from an external water source. The water supply valve may include, for example, a solenoid valve that opens and closes in response to an electrical signal.

[0040] A washing machine may include a detergent supply device configured to supply detergent to a tub. The detergent supply device may include a manual detergent supply device that requires a user to add detergent for each wash cycle, and an automatic detergent supply device that stores a large amount of detergent and automatically supplies a predetermined amount of detergent during a wash cycle. The detergent supply device may include a detergent compartment for storing detergent. The detergent supply device may be configured to supply detergent into the tub during a water supply process. Water supplied through a water supply pipe may be mixed with detergent via the detergent supply device. The water mixed with detergent may be supplied into the tub. Detergent is used as a comprehensive term for pre-wash detergent, main wash detergent, fabric softener, bleach, etc., and the detergent compartment may be divided into a pre-wash detergent storage area, a main wash detergent storage area, a fabric softener storage area, and a bleach storage area.

[0041] A washing machine may include a drainage device configured to discharge water contained in a tub to the outside. The drainage device may include a drain pipe extending from the bottom of the tub to the outside of the housing, a drain valve provided in the drain pipe to open and close the drain pipe, and a pump provided on the drain pipe. The pump may pump water in the drain pipe to the outside of the housing.

[0042] The washing machine may include a control panel positioned on one side of the housing. The control panel may provide a user interface for a user to interact with the washing machine. The user interface may include at least one input interface and at least one output interface.

[0043] At least one input interface can convert sensory information received from a user into an electrical signal.

[0044] At least one input interface may include a power button, an operation button, a course selection dial (or a course selection button), and a wash / rinse / spin setting button. The at least one input interface may include, for example, a tact switch, a push switch, a slide switch, a toggle switch, a micro switch, a touch switch, a touch pad, a touch screen, a jog dial, and / or a microphone.

[0045] At least one output interface can visually or audibly convey information related to the operation of the washing machine to the user.

[0046] For example, at least one output interface may transmit information related to the washing cycle and operating time of the washing machine, as well as washing / rinsing / spin settings to the user. Information related to the operation of the washing machine may be output via a screen, indicator, voice, etc. At least one output interface may include, for example, a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, a speaker, etc.

[0047] The washing machine may include a communication module for communicating with external devices via wires and / or wirelessly.

[0048] The communication module may include at least one of a short-range communication module or a long-range communication module.

[0049] The communication module can transmit data to or receive data from external devices (e.g., a server, a user device, and / or a home appliance). For example, the communication module can establish communication with a server, a user device, and / or a home appliance, and transmit and receive various data.

[0050] To this end, the communication module may support the establishment of a direct (e.g., wired) communication channel or a wireless communication channel between external devices, and the performance of communication through the established communication channel. According to one embodiment, the communication module may include a wireless communication module (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module (e.g., a local area network (LAN) communication module, or a power line communication module). Any of these communication modules may communicate with the external device via a first network (e.g., a short-range communication network such as Bluetooth, wireless fidelity (WiFi) direct, or infrared data association (IrDA)) or a second network (e.g., a long-range communication network such as a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or WAN)). These various types of communication modules may be integrated into a single component (e.g., a single chip) or implemented as multiple separate components (e.g., multiple chips).

[0051] The short-range wireless communication module may include, but is not limited to, a Bluetooth communication module, a BLE (Bluetooth Low Energy) communication module, a near field communication module, a WLAN (Wi-Fi) communication module, a Zigbee communication module, an infrared (IrDA, infrared Data Association) communication module, a WFD (Wi-Fi Direct) communication module, an UWB (ultrawideband) communication module, an Ant+ communication module, a microwave (uWave) communication module, etc.

[0052] The remote communication module may include a communication module that performs various types of remote communication and may include a mobile communication unit. The mobile communication unit transmits and receives wireless signals with at least one of a base station, an external terminal, and a server on a mobile communication network.

[0053] In one embodiment, the communication module can communicate with external devices such as a server, a user device, and other home appliances through a peripheral access point (AP). The access point (AP) can connect a local area network (LAN) to which the washing machine or the user device is connected to a wide area network (WAN) to which the server is connected. The washing machine or the user device can be connected to the server through the wide area network (WAN). The control unit can control various components of the washing machine, such as a drive motor and a water inlet valve. The control unit can control various components of the washing machine to perform at least one cycle, including water supply, washing, rinsing, and / or spin-drying, according to a user input. For example, the control unit can control the drive motor to adjust the rotation speed of the drum, or control the water inlet valve of the water supply device to supply water to the tub.

[0054] The control unit may include hardware such as a CPU or memory, and software such as a control program. For example, the control unit may include an algorithm for controlling the operation of components within the washing machine, at least one memory storing program-type data, and at least one processor performing the aforementioned operation using data stored in the at least one memory. The memory and the processor may each be implemented as separate chips. The processor may include one or more processor chips or one or more processing cores. The memory may include one or more memory chips or one or more memory blocks. Additionally, the memory and the processor may be implemented as a single chip.

[0055] FIG. 1 is a perspective view of a washing machine according to one embodiment of the present disclosure.

[0056] FIG. 2 is a cross-sectional view of a washing machine according to one embodiment of the present disclosure.

[0057] Specifically, FIG. 1 is a perspective view showing a state in which the door (40) of a washing machine (1) according to one embodiment is open.

[0058] Referring to FIGS. 1 and 2, a washing machine (1) according to one embodiment may include a cabinet (10) that forms an exterior and accommodates various components therein, a tub (20) provided inside the cabinet (10) to store a mixture of water and detergent, a drum (30) provided inside the tub (20) to accommodate laundry and rotate, a door (40) rotatably coupled to the cabinet (10), a driving device (60) that rotates the drum (30), a detergent supply unit (90) for supplying detergent to the tub (20), and a detergent cartridge (100) provided to be inserted into / withdrawn from the detergent supply unit (90).

[0059] In one embodiment, the cabinet (10) may have an overall hexahedral shape. In one embodiment, the cabinet (10) may be formed in a box shape with an open front.

[0060] According to one embodiment, the cabinet (10) may include a plurality of panels (11). According to one embodiment, at least one of the plurality of panels (11) may include a PCM steel plate (e.g., a PCM steel plate (200) of FIG. 3) to be described later. The cabinet (10) may include a front panel (11a) provided on an open front (e.g., in the +x-axis direction), side panels (11b, 11c) provided on both sides (e.g., sides facing the ±y-axis direction) behind the front panel (11a), a rear panel (11d) provided on the rear of the cabinet (10) (e.g., in the -x-axis direction), and a top cover (11e) provided on an upper surface (e.g., a side facing the +z-axis direction). Although the cabinet (10) is illustrated as an example in which the rear panel (11d) and both side panels (11b, 11c) are formed integrally, the present disclosure is not limited thereto.

[0061] According to one embodiment, an opening (12) may be formed in the front panel (11a) to allow laundry to be fed into the drum (30). Openings may be formed in the tub (20) and the drum (30) to allow laundry to be fed into or taken out from the front of the cabinet (10), and the openings of the tub (20) and the drum (30) may be positioned to correspond to the opening (12) of the front panel (11a).

[0062] According to one embodiment, the cabinet (10) may include a base (13) provided on the floor. In one embodiment, the base (13) may include a lower frame (13a) formed to cover the lower portion of the cabinet (10) and a lower reinforcing frame (13b) formed to extend from the lower frame (13a).

[0063] According to one embodiment, a water supply device (14) including a water supply pipe (14a) for supplying washing water to a detergent supply unit (90) and / or the tub (20) and a water supply valve (14b) for controlling the water supply of the water supply pipe (14a) may be provided on the upper part of the tub (20). In addition, the water supply device (14) may further include a water supply nozzle (not shown) for spraying washing water into the detergent supply unit (90). The water supply device (14) may be referred to as a water supply unit.

[0064] According to one embodiment, a detergent supply portion (90) having an opening (or, inlet) (90a) through which a detergent cartridge (100) is introduced / withdrawn may be provided on the upper portion of the tub (20). In one embodiment, a cover (15) for opening and closing the opening (90a) may be provided on the front of the washing machine (1). The cover (15) may be rotatably connected to the front of the washing machine (1) (e.g., the front panel (11a).

[0065] In one embodiment, the detergent supply unit (90) may be connected to the water supply pipe (14a) from the rear. In one embodiment, the detergent supply unit (90) may be connected to the upper part of the tub (20) via the supply pipe (16). Water supplied through the water supply pipe (14a) is mixed with detergent through the detergent supply unit (90) via a water supply nozzle (not shown), and the mixed water of water and detergent may be supplied into the interior of the tub (20) via the supply pipe (16).

[0066] According to one embodiment, a diaphragm (17) connecting the opening (12) of the front panel (11a) and the opening of the tub (20) may be provided between the front panel (11a) and the tub (20).

[0067] According to one embodiment, the tub (20) can store a mixture of water and detergent. The tub (20) may be formed in an overall cylindrical shape. In one embodiment, the tub (20) may be fixed inside the cabinet (10). Although not specifically shown in this drawing, a drainage device (not shown) including a drain pipe (not shown) for draining water inside the tub (20) and a drain valve (not shown) may be installed at the bottom of the tub (20). The drainage device may be called a drainage unit.

[0068] According to one embodiment, the tub (20) may be provided to be elastically supported from the cabinet (10) by upper springs (not shown) and lower dampers (80). The springs and dampers (80) may absorb vibration energy between the tub (20) and the cabinet (10) to attenuate vibration when vibration generated when the drum (30) rotates is transmitted to the tub (20) and the cabinet (10).

[0069] According to one embodiment, the drum (30) can perform a washing cycle of raising and lowering laundry while rotating inside the tub (20). A lifter (31) and / or a plurality of holes (32) can be provided on the inner surface of the drum (30). The lifter (31) lifts laundry while the drum (30) rotates, thereby causing the laundry to repeatedly rise and fall, thereby allowing multiple sides of the laundry to be washed evenly. The holes (32) can be passages formed so that water or washing water contained in the tub (20) can flow into the inside of the drum (30), or water or washing water inside the drum (30) can be discharged to the outside.

[0070] According to one embodiment, the door (40) can be rotatably coupled to the front panel (11a) of the cabinet (10). In one embodiment, the door (40) can rotate to open and close the opening (12) of the front panel (11a). In one embodiment, the door (40) can include a door frame (41) and a door glass (43). The door glass (43) can be formed of a transparent tempered glass material so as to allow the interior of the cabinet (10) to be viewed.

[0071] According to one embodiment, a control panel (50) including an input unit (51) for receiving an operation command of the washing machine (1) from a user and an output unit (52) for outputting operation information of the washing machine (1) may be arranged on the front of the cabinet (10). The input unit (51) may be implemented as an input means in the form of a dial switch, as illustrated in this drawing, but the present disclosure is not limited thereto. The output unit (52) may be implemented as an output means in the form of a display, as illustrated in this drawing, but the present disclosure is not limited thereto.

[0072] According to one embodiment, the driving device (60) may be arranged at the rear of the drum (30). In one embodiment, the driving device (60) may be arranged to transmit driving force generated from the motor (61) to the drum (30) through the rotation shaft (67) to rotate the drum (30). In one embodiment, the motor (61) may be configured with a fixed stator (63) and a rotor (65) that rotates by electromagnetically interacting with the stator (63) to convert electrical power into rotational power.

[0073] According to one embodiment, a spray nozzle (70) connected to a circulation hose (71) and spraying the circulated mixed water into the interior of the drum (30) may be provided on one side of the diaphragm (17). In one embodiment, the spray nozzle (70) may be configured to spray the mixed water evenly over the entire laundry accommodated inside the drum (30). In one embodiment, the circulation hose (71) may be connected to a circulation pump (73) for pumping the mixed water stored in the lower part of the tub (20).

[0074] According to one embodiment, the detergent cartridge (100) may be placed at the front upper portion of the tub (20). In one embodiment, the detergent cartridge (100) may be introduced into the washing machine (1) through the opening (90a) of the detergent supply portion (90), or may be withdrawn from the outside of the washing machine (1). In one embodiment, the detergent cartridge (100) may store detergent for washing therein. The detergent may include a general detergent, a neutral detergent, a baby detergent, or a fabric softener. In one embodiment, the detergent cartridge (100), when introduced into the detergent supply portion (90), may automatically supply detergent into the inside of the washing machine (1) (e.g., the tub (20)) by interaction with a nozzle pressurization device (not shown). The detergent cartridge (100) may also be called an automatic detergent drawer.

[0075] FIG. 3 is a schematic diagram illustrating a PCM steel plate for home appliances according to one embodiment of the present disclosure.

[0076] The PCM steel plate (200) of FIG. 3 can constitute at least a portion of a plurality of panels (e.g., a plurality of panels (11) of FIG. 1 and FIG. 2) of a cabinet (e.g., a cabinet (10) of FIG. 1 and FIG. 2) of a washing machine (1) of FIG. 1 and FIG. 2.

[0077] Referring to FIG. 3, the PCM steel plate (200) may include a steel plate (210), a chemical conversion coating layer (220), a primer (230), a base coating layer (240), a print layer (250), and a clear coating layer (260).

[0078] According to one embodiment, the steel plate (210) may include an electrolytic galvanized iron (EGI) steel plate or a galvanized iron (GI) steel plate. However, the type of the steel plate (210) is not limited thereto, and the type of the steel plate (210) may vary depending on the purpose and function. For example, the steel plate (210) may further include stainless steel and cold-rolled steel.

[0079] According to one embodiment, the chemical treatment layer (220) may be disposed on the steel plate (210). The chemical treatment layer (220) may be disposed between the steel plate (210) and the primer (230). The chemical treatment layer (220) may be subjected to a chemical conversion treatment on the steel plate (210) to secure corrosion resistance and interlayer adhesion of the steel plate (210) after a degreasing and rinsing process of the steel plate (210). For example, the chemical treatment layer (220) may be provided in the form of a chemical conversion film by a process such as a phosphate treatment or a chromate treatment.

[0080] According to one embodiment, the primer (230) may be disposed on the Mars treatment layer (220). The primer (230) may be provided to fix a paint (or coating) applied on the steel plate (210). The primer (230) may be referred to as an adhesive layer. The primer (230) may include, for example, a polyester resin. For example, the thickness of the primer (230) may be about 4 um to 6 um. For example, the thickness of the primer (230) may be about 5 um.

[0081] According to one embodiment, a base coating layer (240) may be disposed on a primer (230). The base coating layer (240) may include a main resin, a curing resin, a pigment, a deformer, a leveling agent, and a solvent. For example, the thickness of the base coating layer (240) may be about 12 to 24 μm. For example, the thickness of the base coating layer (240) may be 15 to 20 μm.

[0082] [Table 1] is a table showing the types and contents of the compositions constituting the base coating layer (240). In addition to the components shown in [Table 1], various substances may be included in the base coating layer (240). The unit of each composition is weight %.

[0083] Item composition Ingredient content (wt%) Main resin Polyester resin 50~70 Cured resin Melamine resin 5~15 Pigment Metallic pigment 3~8 Color pigment 3~7 Antifoaming agent and / or leveling agent Acrylic polymer 1~5 Solvent Ester thinner 5~10 Ketone thinner 5~10

[0084] Referring to [Table 1], the main resin of the base coating layer (240) according to one embodiment may include a polyester resin. For example, the base coating layer (240) may include 50 to 70 wt% of the polyester resin relative to the total weight.

[0085] According to one embodiment, the cured resin of the base coating layer (240) may include a melamine resin. For example, the base coating layer (240) may include 5 to 15 wt% of the melamine resin relative to the total weight.

[0086] According to one embodiment, the pigment of the base coating layer (240) may include a metallic pigment. For example, the base coating layer (240) may include 3 to 8 wt% of the metallic pigment.

[0087] In one embodiment, the pigment of the base coating layer (240) may include a colored pigment. For example, the colored pigment may include a pigment of a color such as black, blue, or red. For example, the base coating layer (240) may include 3 to 7 wt% of the colored pigment.

[0088] In one embodiment, the defoaming agent and / or leveling agent of the base coating layer (240) may include an acrylic polymer. For example, the base coating layer (240) may include 1 to 5 wt % of the acrylic polymer.

[0089] According to one embodiment, the solvent of the base coating layer (240) may include an ester-based thinner and / or a ketone-based thinner. For example, the base coating layer (240) may include 5 to 10 wt % of an ester-based thinner. For example, the base coating layer (240) may include 5 to 10 wt % of a ketone-based thinner.

[0090] In one embodiment, the print layer (250) may be disposed on the base coating layer (240). For example, the print layer (250) may be adhered to the base coating layer (240) to maintain the printed color and / or pattern. For example, the thickness of the print layer (250) may be 0.8 to 2.4 um. For example, the thickness of the print layer (250) may be 1 to 2 um.

[0091] According to one embodiment, the print layer (250) may be formed by 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 according 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, for example, UV-curable ink. The print layer (250) formed by the digital printing method can maintain the printed design for a long time due to its strong adhesiveness with the base coating layer (240).

[0092] According to one embodiment, a clear coating layer (260) may be disposed on the print layer (250). The clear coating layer (260) may be provided to improve the appearance by imparting gloss to the surface of the PCM steel plate (200). The clear coating layer (260) may be provided to protect the print layer (250) from the outside. For example, the clear coating layer (260) may be disposed on the outer surface of the steel plate (210) and the print layer (250) to protect the steel plate (210) and the print layer (250) from external environments such as physical impact, corrosion, or ultraviolet rays. For example, the thickness of the clear coating layer (260) may be about 8 um to 12 um. For example, the thickness of the clear coating layer (260) may be about 10 um.

[0093] According to one embodiment, the clear coating layer (260) may include a main resin, a curing resin, a deformer, a leveling agent, and a solvent.

[0094] [Table 2] is a table showing the types and contents of the compositions constituting the clear coating layer (260). In addition to the compositions shown in [Table 2], various substances may be included in the clear coating layer (260). The unit for each composition is weight %.

[0095] Item composition Ingredient content (wt%) Main resin Polyester resin 60~75 Cured resin Melamine resin 10~20 Defoamer and / or leveling agent Acrylic polymer 1~5 Solvent Ester thinner 5~15 Ketone thinner 5~15

[0096] Referring to [Table 2], the main resin of the clear coating layer (260) according to one embodiment may include a polyester resin. For example, the clear coating layer (260) may include 60 to 75 wt% of the polyester resin relative to the total weight.

[0097] According to one embodiment, the cured resin of the clear coating layer (260) may include melamine resin. For example, the clear coating layer (260) may include 10 to 20 wt% of the melamine resin relative to the total weight.

[0098] In one embodiment, the clear coating layer (260) may include an acrylic polymer as a defoaming agent and / or leveling agent. For example, the clear coating layer (260) may include 1 to 5 wt% of the acrylic polymer.

[0099] According to one embodiment, the solvent of the clear coating layer (260) may include an ester-based thinner and / or a ketone-based thinner. For example, the clear coating layer (260) may include 5 to 15 wt % of an ester-based thinner. For example, the clear coating layer (260) may include 5 to 15 wt % of a ketone-based thinner.

[0100] According to one embodiment, an adhesive layer may be provided between the print layer (250) and the clear coating layer (260). The adhesive layer may include, but is not limited to, a UV adhesive that rapidly cures through ultraviolet curing. The adhesive layer may also be omitted from the configuration of the PCM steel plate (200).

[0101] FIG. 4 is a graph showing the gloss, processability, and hardness according to the molecular weight of the polyester resin of the clear coating layer according to one embodiment of the present disclosure.

[0102] According to one embodiment, the clear coating layer (260) of the PCM steel plate (200) may include a polyester resin as the main resin.

[0103] In the case of PCM steel sheets used in the cabinet (e.g., front panel (11a)) of a washing machine (1), a polyester resin having a high molecular weight (e.g., a polyester resin having a molecular weight of 10,000 to 30,000 Mw) is used to ensure formability. In the case of polyester resins, the higher the molecular weight, the higher the elongation of the paint film, which may increase the formability of the PCM steel sheet. However, as the molecular weight of the polyester increases, the viscosity and fluidity of the resin decrease, which may reduce the gloss and / or distinctness of reflective image (DOI) of the PCM steel sheet. In addition, as the molecular weight of the polyester increases, the hardness (or scratch resistance) of the PCM steel sheet may decrease. For these reasons, the appearance quality of the PCM steel sheet may be inferior to that of the VCM steel sheet. Therefore, there is a need to develop a PCM steel sheet that secures the appearance quality and hardness at the level of the VCM steel sheet.

[0104] Below, the composition of the PCM steel plate (200) to secure the appearance quality and hardness of the PCM steel plate will be described.

[0105] [Table 3] is a table showing the gloss, clarity of image (DOI), moldability test results, and surface hardness of the clear coating layer (260) according to the molecular weight of the polyester resin of the clear coating layer (260). The moldability test may include a bending test, a cupping test, an impact test, and a press test. The bending test was performed under 0T conditions where the steel plates were bent and brought into contact with each other. Here, the gloss was measured by using a gloss meter to measure the amount of reflection when light was incident on the surface at a 20 degree angle.

[0106] Molecular Weight (Mw) 5000~8000 8000~12000 20000~25000 20˚ Gloss (GU) 91.28 2.18 0.3 Clearness (DOI) 47.141.739.4 Bending Test (0T) No Crack No Crack No Crack Cup Test Crack No Crack No Crack Impact Test Whitening Occurrence No Whitening No Whitening Press Test Whitening Occurrence No Whitening No Whitening Surface Hardness FHB2B~B

[0107] Referring to [Table 3], when the molecular weight of the polyester resin of the clear coating layer (260) is 5000 to 8000 mw, it can be confirmed that the clear coating layer (260) has a gloss of 91.2 GU and a sharpness of 47.1. In addition, it can be confirmed that cracks and whitening occurred in the molding processability test of the clear coating layer (260) excluding the bending test. In addition, it can be confirmed that the hardness of the clear coating layer (260) is F.

[0108] When the molecular weight of the polyester resin of the clear coating layer (260) is 8000 to 12000 mw, it can be confirmed that the clear coating layer (260) has a gloss of 82.1 GU and a sharpness of 41.7. In addition, it can be confirmed that no cracks or whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is HB.

[0109] When the molecular weight of the polyester resin of the clear coating layer (260) is 20,000 to 25,000 mw, it can be confirmed that the clear coating layer (260) has a gloss of 80.3 GU and a sharpness of 39.4. In addition, it can be confirmed that cracks and whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is 2B to B.

[0110] Referring to FIG. 4 based on the data values ​​of [Table 3], it can be confirmed again that as the molecular weight of the polyester resin included in the clear coating layer (260) increases, the molding processability is good, but the gloss, clarity, and surface hardness decrease.

[0111] As a result, the clear coating layer (260) can secure a gloss of about 82 GU, moldability, and a hardness of HB or higher when the molecular weight of the polyester resin is 8000 to 12000 Mw.

[0112] According to one embodiment, the clear coating layer (260) may include a polyester resin and an acrylic resin. The acrylic resin is an amorphous resin that exhibits low light scattering and high transparency due to its structural and optical properties. When the clear coating layer (260) includes an acrylic resin, the glossiness of the clear coating layer (260) may be improved due to the physical properties of the acrylic resin.

[0113] [Table 4] is a table showing the gloss, moldability, and surface hardness according to the ratio of polyester resin and acrylic resin in the clear coating layer (260).

[0114] Polyester: Acrylic 100:09 5:59 0:10 85:15 80:20 Gloss 82.1 85.5 86.0 86.8 86.5 Bending Test (0T) No Crack No Crack No Crack No Crack No Crack Impact Test No Whitening No Whitening No Whitening Occurrence Whitening Occurrence Surface Hardness BHBHBHBF

[0115] Referring to [Table 4], when the ratio of polyester resin and acrylic resin included in the clear coating layer (260) is 100 to 0, it can be confirmed that the gloss of the clear coating layer (260) has a value of 82.1 GU. In addition, it can be confirmed that no cracks or whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is B.

[0116] When the ratio of polyester resin and acrylic resin included in the clear coating layer (260) is 95 to 5, it can be confirmed that the gloss of the clear coating layer (260) has a value of 85.5 GU. In addition, it can be confirmed that no cracks or whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is HB.

[0117] When the ratio of polyester resin and acrylic resin included in the clear coating layer (260) is 90 to 10, it can be confirmed that the gloss of the clear coating layer (260) has a value of 86.0 GU. In addition, it can be confirmed that no cracks or whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is HB.

[0118] When the ratio of polyester resin and acrylic resin included in the clear coating layer (260) is 85 to 15, it can be confirmed that the gloss of the clear coating layer (260) has a value of 86.8 GU. In addition, it can be confirmed that no cracks occurred in the molding processability test of the clear coating layer (260). On the other hand, it can be confirmed that whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is HB.

[0119] When the ratio of polyester resin and acrylic resin included in the clear coating layer (260) is 80 to 20, it can be confirmed that the gloss of the clear coating layer (260) has a value of 86.5 GU. In addition, it can be confirmed that no cracks occurred in the molding processability test of the clear coating layer (260). On the other hand, it can be confirmed that whitening occurred in the molding processability test of the clear coating layer (260). In addition, it can be confirmed that the hardness of the clear coating layer (260) is F.

[0120] As the acrylic resin content in polyester resin increases, glossiness improves. However, it can be confirmed that glossiness converges when the acrylic resin content is 15% or higher. In addition, it can be confirmed that surface hardness exceeding HB is secured when the acrylic resin content is 5% or higher. However, it can be confirmed that moldability is not secured when the acrylic resin content is 15% or higher because whitening occurs.

[0121] As a result, the clear coating layer (260) can secure a gloss of 85.5 to 86.0 GU, moldability, and surface hardness of HB or higher when the ratio of acrylic resin to polyester resin is 5 to 10%.

[0122] FIG. 5 is a graph showing the clarity and brightness according to particle size and content of aluminum paste, which is a metallic pigment of a base coating layer according to one embodiment of the present disclosure.

[0123] FIG. 6 is a graph showing the clarity and brightness according to particle size and content of aluminum paste, which is a metallic pigment of a base coating layer according to one embodiment of the present disclosure.

[0124] In one embodiment, the base coating layer (240) of the PCM steel sheet (200) may include a metallic pigment. In one embodiment, the metallic pigment of the base coating layer (240) may include an aluminum paste. The aluminum paste may be used to improve the gloss and / or brightness of the PCM steel sheet (200) by utilizing a mirror effect. However, in the case of the PCM steel sheet, as the particle size of the pigment increases, the surface roughness increases, which may reduce the gloss and / or clarity.

[0125] Referring to FIGS. 5 and 6, in the case of aluminum paste at 4 wt% relative to the total weight of the base coating layer (240), when the particle size of the aluminum paste is 12 μm, the PCM steel plate (200) can have sharpness of 61.8 and luminance of 9.12 cd / ㎡. In the case of aluminum paste at 4 wt% relative to the total weight of the base coating layer (240), the PCM steel plate (200) can have sharpness of 53.6 and luminance of 9.42 cd / ㎡ when the particle size of the aluminum paste is 19 μm. In the case of aluminum paste at 4 wt% relative to the total weight of the base coating layer (240), the PCM steel plate (200) can have sharpness of 50.5 and luminance of 9.34 cd / ㎡ when the particle size of the aluminum paste is 23 μm. In the case of 4 wt% of aluminum paste relative to the total weight of the base coating layer (240), the PCM steel plate (200) can have a sharpness of 42 and a brightness of 11.2 cd / ㎡ when the particle size of the aluminum paste is 32 um.

[0126] In the case of 8 wt% of aluminum paste relative to the total weight of the base coating layer (240), the PCM steel sheet (200) can have a sharpness of 56.5 and a luminance of 9.31 cd / ㎡ when the particle size of the aluminum paste is 12 um. In the case of 8 wt% of aluminum paste relative to the total weight of the base coating layer (240), the PCM steel sheet (200) can have a sharpness of 46.7 and a luminance of 10.9 cd / ㎡ when the particle size of the aluminum paste is 19 um. In the case of 8 wt% of aluminum paste relative to the total weight of the base coating layer (240), the PCM steel sheet (200) can have a sharpness of 34.6 and a luminance of 10.46 cd / ㎡ when the particle size of the aluminum paste is 23 um. In the case of 8 wt% of aluminum paste relative to the total weight of the base coating layer (240), the PCM steel plate (200) can have a sharpness of 24.4 and a brightness of 12.46 cd / ㎡ when the particle size of the aluminum paste is 32 um.

[0127] Consequently, as the particle size of the aluminum paste decreases, the particle density per unit area increases, which can improve sharpness. As the aluminum paste size increases, interference between particles decreases, which reduces diffuse reflection and can therefore increase brightness. However, compared to sharpness, the difference in brightness due to changes in particle size is minimal.

[0128] FIG. 7 is a graph showing the gloss, clarity, and brightness according to particle size and particle shape of an aluminum paste according to one embodiment of the present disclosure.

[0129] According to one embodiment, the aluminum paste, which is a metallic pigment in the base coating layer (240), may have various forms. For example, the aluminum paste may have a cornflake (or flake) shape or a silver coin (e.g., a silver dollar) shape. The aluminum paste in the cornflake form may be called aluminum flake.

[0130] Referring to Fig. 7, in the case of the aluminum paste in the form of corn flakes, when the content of the aluminum paste is 12 wt% and the particle size is 10 to 12 μm, the glossiness may have a value of 94.3 GU, the clarity of image (DOI) may have a value of 57.7, and the luminance (FI) may have a value of 10.11 cd / ㎡. When the content of the aluminum paste is 6 wt% and the particle size is 19 to 21 μm, the glossiness may have a value of 84.9 GU, the clarity of image (DOI) may have a value of 44.5, and the luminance (FI) may have a value of 12.9 cd / ㎡. When the content of the aluminum paste is 2.5 to 3 wt% and the particle size is 30 to 32 μm, the glossiness may have a value of 74.8 GU, the clarity of image (DOI) may have a value of 33.4, and the luminance (FI) may have a value of 11.23 cd / ㎡.

[0131] In the case of the aluminum paste in the form of a silver dollar, when the content of the aluminum paste is 12 wt% and the particle size is 10 to 12 μm, the glossiness can have a value of 94.5 GU, the clarity of image (DOI) can have a value of 57.3, and the luminance (FI) can have a value of 11.23 cd / ㎡. When the content of the aluminum paste is 6 wt% and the particle size is 19 to 21 μm, the glossiness can have a value of 84.6 GU, the clarity of image (DOI) can have a value of 43.7, and the luminance (FI) can have a value of 11.64 cd / ㎡. When the content of the aluminum paste is 2.5 to 3 wt% and the particle size is 30 to 32 μm, the glossiness can have a value of 64.3 GU, the clarity of image (DOI) can have a value of 16.4, and the luminance (FI) can have a value of 11.17 cd / ㎡.

[0132] In the case of aluminum paste in the form of silver dahlias, the particle shape is round and regularized, so the circumference length is shorter in relation to the surface area compared to aluminum paste in the form of irregular corn flakes, which can reduce light scattering.

[0133] As a result, the aluminum paste in the form of a silver dollar can secure high brightness (e.g., brightness of 9 cd / ㎡ or more) while securing gloss and sharpness even when the particle size is small, such as 10 to 12 μm.

[0134] A PCM steel plate (200) for a home appliance according to one embodiment of the present disclosure may include a steel plate (210), a chemical treatment layer (220) disposed on the steel plate (210), a primer (230) disposed on the chemical treatment layer (220), a base coating layer (240) disposed on the primer (230) and including a pigment, a print layer (250) disposed on the base coating layer (240), and a clear coating layer (260) disposed on the print layer (250) and including a polyester resin. The average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0135] According to one embodiment, the clear coating layer (260) may further include an acrylic resin.

[0136] According to one embodiment, the content ratio of the acrylic resin relative to the polyester resin may be 5 to 10%.

[0137] According to one embodiment, the pigment of the base coating layer (240) may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0138] In one embodiment, the aluminum paste may include round, regular particles corresponding to silver dollars.

[0139] In one embodiment, the particles may have a particle size of 10 to 20 um.

[0140] According to one embodiment, the clear coating layer (260) may have a surface hardness of HB or higher.

[0141] According to one embodiment, the clear coating layer (260) may have a 20 degree gloss of 80 GU or more.

[0142] According to one embodiment, the clear coating layer (260) may have a depth of image (DOI) of 40 or more.

[0143] According to one embodiment, the clear coating layer (260) may have a luminance of 9 cd / ㎡ or more.

[0144] A washing machine (1) according to one embodiment of the present disclosure may include a casing (10) including a plurality of panels (11), a tub (20) disposed within the casing (10), and a drum (30) rotatably disposed within the tub (20). The plurality of panels (11) may include a PCM steel plate (200). The PCM steel plate (200) may include a steel plate (210), a chemical treatment layer (220) disposed on the steel plate (210), a primer (230) disposed on the chemical treatment layer (220), a base coating layer (240) disposed on the primer (230) and including a pigment, a print layer (250) disposed on the base coating layer (240), and a clear coating layer (260) disposed on the print layer (250) and including a polyester resin. The average molecular weight (Mw) of the above polyester resin may be 8000 to 12000.

[0145] According to one embodiment, the clear coating layer (260) may further include an acrylic resin.

[0146] According to one embodiment, the content ratio of the acrylic resin relative to the polyester resin may be 5 to 10%.

[0147] According to one embodiment, the pigment of the base coating layer (240) may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0148] In one embodiment, the aluminum paste may include round, regular particles corresponding to silver dollars.

[0149] In one embodiment, the particles may have a particle size of 10 to 20 um.

[0150] According to one embodiment, the clear coating layer (260) may have a surface hardness of HB or higher.

[0151] According to one embodiment, the clear coating layer (260) may have a 20 degree gloss of 80 GU or more.

[0152] According to one embodiment, the clear coating layer (260) may have a depth of image (DOI) of 40 or more.

[0153] According to one embodiment, the clear coating layer (260) may have a luminance of 9 cd / ㎡ or more.

[0154] 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 plate (200) for home appliances, Steel plate (210); A Mars treatment layer (220) disposed on the above steel plate (210); A primer (230) placed on the above Mars treatment layer (220); A base coating layer (240) disposed on the above primer (230) and containing a pigment; A print layer (250) placed on the base coating layer (240); and A clear coating layer (260) is disposed on the above print layer (250) and includes a polyester resin, PCM steel sheet, wherein the average molecular weight (Mw) of the above polyester resin is 8000 to 12000.

2. In paragraph 1, The above clear coating layer (260) is a PCM steel plate further containing acrylic resin.

3. In paragraph 2, A PCM steel sheet having a content ratio of the acrylic resin relative to the polyester resin of 5 to 10%.

4. In any one of paragraphs 1 to 3, The pigment of the above base coating layer (240) includes a metallic pigment, The above metallic pigment is a PCM steel sheet containing aluminum paste.

5. In paragraph 4, The above aluminum paste is a PCM steel sheet containing round and regular particles corresponding to silver dollars.

6. In paragraph 5, The above particles are PCM steel sheets having a particle size of 10 to 20 um.

7. In any one of paragraphs 1 to 6, The above clear coating layer (260) is a PCM steel plate having a surface hardness of HB or higher.

8. In any one of paragraphs 1 to 7, The above clear coating layer (260) is a PCM steel plate having a 20 degree gloss of 80GU or more.

9. In any one of paragraphs 1 to 8, The above clear coating layer (260) is a PCM steel plate having a depth of image (DOI) of 40 or more.

10. In any one of paragraphs 1 to 9, The above clear coating layer (260) is a PCM steel plate having a brightness of 9 cd / ㎡ or more.

11. In the washing machine (1), A casing (10) comprising a plurality of panels (11); A tub (20) placed within the above casing (10); and It includes a drum (30) that is rotatably arranged within the above tub (20), The above plurality of panels (11) include PCM steel plates (200), The above PCM steel plate (200) is Steel plate (210); A Mars treatment layer (220) disposed on the above steel plate (210); A primer (230) placed on the above Mars treatment layer (220); A base coating layer (240) disposed on the above primer (230) and containing a pigment; A print layer (250) placed on the base coating layer (240); and A clear coating layer (260) is disposed on the above print layer (250) and includes a polyester resin, A washing machine, wherein the average molecular weight (Mw) of the polyester resin is 8000 to 12000.

12. In paragraph 11, A washing machine, wherein the above clear coating layer (260) further contains acrylic resin.

13. In paragraph 12, A washing machine having a content ratio of the acrylic resin relative to the polyester resin of 5 to 10%.

14. In any one of paragraphs 11 to 13, The pigment of the above base coating layer (240) includes a metallic pigment, The metallic pigment is a washing machine containing aluminum paste.

15. In paragraph 14, The above aluminum paste is a washing machine containing round and regular particles corresponding to a silver dollar.

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