PCM steel sheet for home appliance and washing machine including the same

Abstract

A pre-coated metal (PCM) steel sheet for a home appliance may include: a steel sheet; a chemical conversion coating layer on the steel sheet; a primer on the chemical conversion coating layer; a base coating layer on the primer, the base coating layer including a pigment; a print layer on the base coating layer; and a clear coating layer on the print layer, the clear coating layer including a polyester resin, wherein an average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application is a continuation of an International application No. PCT / KR2025 / 007251 designating the United States, filed on May 28, 2025, in the Korean Intellectual Property Receiving Office, which claims priority from Korean Patent Application No. 10-2024-0107070, filed on Aug. 9, 2024, in the Korean Intellectual Property Office, the disclosures of each of which are incorporated by reference herein in their entireties.TECHNICAL FIELD

[0002] Various embodiments of the disclosure relate to a pre-coated metal (PCM) steel sheet and a washing machine including the same.BACKGROUND ART

[0003] Home appliances, such as washing machines, may include a steel sheet for implementing the exterior. Pre-coated metal (PCM) steel sheets or vinyl-coated metal (VCM) steel sheets may be adopted as such steel sheets. To implement various patterns to suit the needs of consumers, it may be appropriate to use VCM steel sheets, which are high-gloss and high-DOI steel sheets, instead of PCM steel sheets. However, use of VCM steel plates may increase the production costs.

[0004] The above-described information may be provided as related art for the purpose of helping understanding of the disclosure. No claim or determination is made as to whether any of the foregoing is applicable as background art in relation to the disclosure.DISCLOSURE OF INVENTIONSolution to Problems

[0005] Various embodiments of the disclosure may implement high gloss, high DOI, or high luminance at the level of the VCM by adopting a digital printing method and adjusting the composition the coating layer.

[0006] In accordance with the present disclosure, a pre-coated metal (PCM) steel sheet for a home appliance may include: a steel sheet; a chemical conversion coating layer on the steel sheet; a primer on the chemical conversion coating layer; a base coating layer on the primer, the base coating layer including a pigment; a print layer on the base coating layer; and a clear coating layer on the print layer, the clear coating layer including a polyester resin, wherein an average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0007] In accordance with the present disclosure, a washing machine may include: a casing including a plurality of panels; a tub in the casing; and a drum in the tub, the drum configured to rotate in the tub, wherein the plurality of panels may include a pre-coated metal (PCM) steel sheet, and the PCM steel sheet may include: a steel sheet, a chemical conversion coating layer on the steel sheet, a primer on the chemical conversion coating layer, a base coating layer on the primer, the base coating layer including a pigment, a print layer on the base coating layer, and a clear coating layer on the print layer, the clear coating layer including a polyester resin, and average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0008] The disclosure is not limited to the foregoing embodiments but various modifications or changes may rather be made thereto without departing from the spirit and scope of the disclosure.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a perspective view illustrating a washing machine according to an embodiment;

[0010] FIG. 2 is a cross-sectional view illustrating a washing machine according to an embodiment;

[0011] FIG. 3 is a view schematically illustrating a PCM steel sheet for a home appliance according to an embodiment;

[0012] FIG. 4 is a graph illustrating the gloss, processability, and hardness according to the molecular weight of a polyester resin of a clear coating layer according to an embodiment of the disclosure;

[0013] FIG. 5 is a graph illustrating the DOI and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure;

[0014] FIG. 6 is a graph illustrating the DOI and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure; and

[0015] FIG. 7 is a graph illustrating the gloss, DOI, and luminance according to the particle size, per particle shape, of an aluminum paste according to an embodiment of the disclosure.

[0016] Reference may be made to the accompanying drawings in the following description, and specific examples that may be practiced are shown as examples within the drawings. Other examples may be utilized and structural changes may be made without departing from the scope of the various examples.MODE FOR THE INVENTION

[0017] It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment.

[0018] With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements.

[0019] It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise.

[0020] As used herein, each of such phrases as “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 all possible combinations of the items enumerated together in a corresponding one of the phrases.

[0021] The term “and / or” may denote a combination(s) of a plurality of related components as listed or any of the components.

[0022] As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order).

[0023] As used herein, the terms ‘front surface,’‘rear surface,’‘upper surface,’‘side surface,’‘left side,’‘right side,’‘upper portion,’ and ‘lower portion’ are defined with respect to the drawings, and the shape and position of each component are not limited by the terms.

[0024] It will be further understood that the terms “comprise” and / or “have,” as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] It will be understood that when a component is referred to as “connected to,”“coupled to”, “supported on,” or “contacting” another component, the components may be connected to, coupled to, supported on, or contact each other directly or via a third component.

[0026] Throughout the specification, when one component is positioned “on” another component, the first component may be positioned directly on the second component, or other component(s) may be positioned between the first and second component.

[0027] A home appliance according to various embodiments may include a clothing treatment device. The washing machine, which is a clothing treatment device, may perform washing, rinsing, spinning, and drying cycles. The washing machine is an example of the clothing treatment device. The clothing treatment device encompasses devices for washing clothes (objects to be washed or objects to be dried), devices for drying clothes, and devices capable of performing both washing and drying of clothes.

[0028] The washing machine according to various embodiments may include a top-loading washing machine in which a laundry inlet for inserting or withdrawing laundry faces upward, or a front-loading washing machine in which a laundry inlet faces forward. The washing machine according to various embodiments may include a washing machine having various loading schemes other than the top-loading and front-loading washing machines described above.

[0029] The top-loading washing machine may wash laundry using a water flow generated by a rotating body such as a pulsator. The front-loading washing machine may wash laundry by repeatedly raising and dropping the laundry by rotating the drum. The front-loading washing machine may include a dryer cum washing machine capable of drying laundry accommodated in the drum. The dryer cum washing machine may include a hot air supply device for supplying high-temperature air into the drum and a condensation device for removing moisture from the air discharged from the drum. For example, the dryer cum washing machine may include a heat pump device. The washing machine according to various embodiments may include a washing machine of a washing method other than the above-described washing method.

[0030] The washing machine according to various embodiments may include a housing accommodating various components therein. The housing may be provided in the form of a box having a laundry inlet formed in one side thereof.

[0031] The washing machine may include a door for opening and closing the laundry inlet. The door may be rotatably mounted on the housing by a hinge. At least a portion of the door may be provided to be transparent or translucent so that the inside of the housing is visible.

[0032] The washing machine may include a tub provided inside the housing to store water. The tub may be provided in a substantially cylindrical shape with a tub opening formed in one side thereof, and may be disposed inside the housing so that the tub opening is disposed to correspond to the laundry inlet.

[0033] The tub may be connected to the housing by a damper. The damper may absorb vibrations generated when the drum rotates and attenuate vibrations transferred to the housing.

[0034] The washing machine may include a drum provided to accommodate laundry.

[0035] The drum may be disposed inside the tub so that a drum opening provided in one side corresponds to the laundry inlet and the tub opening. The laundry may be accommodated in the drum or withdrawn from the drum by sequentially passing through the laundry inlet, the tub opening, and the drum opening.

[0036] The drum may perform each operation according to washing, rinsing, and / or spinning cycles while rotating inside the tub. A plurality of through holes may be formed in the cylindrical wall of the drum to allow water stored in the tub to flow into or out of the drum.

[0037] The washing machine may include a driving device configured to rotate the drum. The driving device may include a driving motor and a rotation shaft for transferring the driving force generated by the driving motor to the drum. The rotating shaft may be connected to the drum through the tub.

[0038] The driving device may perform each operation according to washing, rinsing, and / or spinning, or drying cycle by rotating the drum forward or backward.

[0039] The washing machine may include a water supply device configured to supply water to the tub. The water supply device may include a water supply pipe and a water supply valve provided in the water supply pipe. The water supply pipe may be connected to an external water supply source. The water supply pipe may extend from an external water supply source to the 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.

[0040] The water supply valve may open or close the water supply pipe in response to an electrical signal from the controller. The water supply valve may allow or block water from being supplied from an external water supply source to the tub. The water supply valve may include, e.g., a solenoid valve that is opened and closed in response to an electrical signal.

[0041] The washing machine may include a detergent supply device configured to supply detergent to the tub. The detergent supply device may include a manual detergent supply device in which the user needs to put a detergent to be used for each washing, and an automatic detergent supply device in which a large amount of detergent is stored and a predetermined amount of detergent is automatically put into the washing. The detergent supply device may include a detergent container for storing the detergent. The detergent supply device may be configured to supply detergent into the tub during a water supply process. Water supplied through the water supply pipe may be mixed with the detergent via the detergent supply device. Water mixed with the detergent may be supplied into the tub. Detergent is used as a term encompassing a detergent for pre-washing, a detergent for main washing, a fabric softener, a bleach, or the like, and the detergent container may be divided into a pre-washing detergent storage area, a main washing detergent storage area, a fabric softener storage area, and a bleach storage area.

[0042] The washing machine may include a drain device configured to discharge water contained in the tub to the outside. The drain device may include a drain pipe extending from a lower portion 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 from the drain pipe to the outside of the housing.

[0043] The washing machine may include a control panel disposed on one side surface of the housing. The control panel may provide a user interface for the user and the washing machine to interact with each other. The user interface may include at least one input interface and at least one output interface.

[0044] At least one input interface may convert sensory information received from the user into an electrical signal.

[0045] The at least one input interface may include a power button, an operation button, a course selection dial (or a course selection button), and a washing / rinsing / spinning setting button. The at least one input interface may include, e.g., 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.

[0046] The at least one output interface may visually or audibly transfer information related to the operation of the washing machine to the user.

[0047] For example, the at least one output interface may transfer information related to the washing course, the operation time of the washing machine, and the washing setting / rinsing setting / spinning setting to the user. The information about the operation of the washing machine may be output as a screen, an indicator, a voice, etc. The at least one output interface may include, e.g., a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, a speaker, or the like.

[0048] The washing machine may include a communication module for wired and / or wireless communication with an external device.

[0049] The communication module may include at least one of a short-range communication module or a long-range communication module.

[0050] The communication module may transmit data to an external device (e.g., a server, a user device, and / or a home appliance) or may receive data from the external device. For example, the communication module may establish communication with a server and / or the user device and / or a home appliance, and transmit and receive various data.

[0051] To that end, the communication module may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between external devices and performing communication through the established communication channel. According to an 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 (PLC) module). A corresponding one 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 (Wi-Fi) 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., local area network (LAN) or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other.

[0052] The short-range wireless communication module may include, but is not limited to, a Bluetooth communication module, a BLE communication module, a near field communication module, a WLAN (Wi-Fi) communication module, a Zigbee communication module, an infrared data association (IrDA) communication module, a Wi-Fi direct (WFD) communication module, an ultrawideband (UWB) communication module, an Ant+ communication module, and a microwave (uWave) communication module.

[0053] The long-range communication module may include a communication module that performs various types of long-range communication, and may include a mobile communication unit. The mobile communication unit transmits and receives a wireless signal to and from at least one of a base station, an external terminal, and a server over a mobile communication network.

[0054] In an embodiment, the communication module may communicate with an external device such as a server, a user equipment, another home appliance, or the like through an access point (AP). The AP may connect the local area network (LAN) to which the washing machine or the user equipment is connected to the wide area network (WAN) to which the server is connected. The washing machine or the user device may be connected to the server through the wide area network (WAN). The controller may control various components (e.g., a driving motor and a water supply valve) of the washing machine. The controller may control various components of the washing machine to perform at least one cycle including water supply, washing, rinsing, and / or spinning according to the user input. For example, the controller may control the driving motor to adjust the rotational speed of the drum, or control the water supply valve of the water supply device to supply water to the tub.

[0055] The controller may include hardware such as a CPU or a memory, and software such as a control program. For example, the controller may include an algorithm for controlling operations of the components in the washing machine, at least one memory for storing data in the form of a program, and at least one processor for performing the above-described operations using the data stored in the at least one memory. The memory and the processor may be implemented as separate chips, respectively. The processor may include one or more processor chips or may include one or more processing cores. The memory may include one or more memory chips or may include one or more memory blocks. Further, the memory and the processor may be implemented as a single chip.

[0056] FIG. 1 is a perspective view illustrating a washing machine according to an embodiment of the disclosure;

[0057] FIG. 2 is a cross-sectional view illustrating a washing machine according to an embodiment of the disclosure.

[0058] Specifically, FIG. 1 is a perspective view illustrating a state in which a door 40 of a washing machine 1 according to an embodiment is opened.

[0059] Referring to FIGS. 1 and 2, a washing machine 1 according to an embodiment may include a cabinet 10 forming an outer appearance and accommodating various components therein, a tub 20 provided inside the cabinet 10 to store mixed water in which water and detergent are mixed, 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 rotating the drum 30, a detergent supply unit 90 for supplying the detergent to the tub 20, and a detergent cartridge 100 provided to be drawn in / out the detergent supply unit 90.

[0060] According to an embodiment, the cabinet 10 may have a hexahedral shape as a whole. In an embodiment, the cabinet 10 may be formed in a box shape with an open front.

[0061] According to an embodiment, the cabinet 10 may include a plurality of panels 11. According to an embodiment, at least one of the plurality of panels 11 may include a PCM steel sheet (e.g., the PCM steel sheet 200 of FIG. 3) to be described below. The cabinet 10 may include a front panel 11a provided in the open front (e.g., the +x-axis direction), side panels 11b and 11c disposed on two opposite side surfaces (e.g., the surfaces facing in the ±y-axis directions) rearward of the front panel 11a, a rear panel 11d provided at the rear (e.g., the −x-axis direction) of the cabinet 10, and a top cover 11e provided on an upper surface (e.g., the surface facing in the +z-axis direction) thereof. An example in which in the cabinet 10, the rear panel 11d and two opposite side panels 11b and 11c are integrally formed is illustrated, but the disclosure is not limited thereto.

[0062] According to an embodiment, an opening 12 may be formed in the front panel 11a to allow laundry to be put into the drum 30. Openings may be formed in the tub 20 and the drum 30 to allow laundry to be put in or out 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.

[0063] According to an embodiment, the cabinet 10 may include a base 13 provided at the bottom. In an embodiment, the base 13 may include a lower frame 13a formed to cover a lower portion of the cabinet 10 and a lower reinforcing frame 13b formed to extend from the lower frame 13a.

[0064] According to an embodiment, a water supply device 14 including a water supply pipe 14a for supplying washing water to the detergent supply unit 90 and / or the tub 20, and a water supply valve 14b for controlling water supply of the water supply pipe 14a may be provided above the tub 20. Further, the water supply device 14 may further include a water supply nozzle (not shown) for jetting washing water into the detergent supply unit 90. The water supply device 14 may be referred to as a water supply unit.

[0065] According to an embodiment, the detergent supply unit 90 having an opening (or inlet) 90a through which the detergent cartridge 100 is drawn in / out may be provided above the tub 20. In an embodiment, a cover 15 may be provided in the front of the washing machine 1 to open / close the opening 90a. The cover 15 may be rotatably connected to the front surface (e.g., the front panel 11a) of the washing machine 1.

[0066] According to an embodiment, the detergent supply unit 90 may be connected to the water supply pipe 14a from the rear. In an embodiment, the detergent supply unit 90 may be connected to an upper portion of the tub 20 through a supply pipe 16. The water supplied through the water supply pipe 14a may be mixed with the detergent via the detergent supply device 90 through the water supply nozzle (not shown), and the mixed water in which the water and the detergent are mixed may be supplied into the tub 20 through the supply pipe 16.

[0067] According to an 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.

[0068] According to an embodiment, the tub 20 may store mixed water in which water and a detergent are mixed. The tub 20 may be formed in a cylindrical shape as a whole. In an embodiment, the tub 20 may be fixed inside the cabinet 10. Although not specifically shown in the drawings, a drain 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 under the tub 20. The drain device may be referred to as a drain unit.

[0069] According to an embodiment, the tub 20 may be provided to be elastically supported from the cabinet 10 by an upper spring (not shown) and lower dampers 80. When vibration generated when the drum 30 rotates is transferred to the tub 20 and the cabinet 10, the spring and dampers 80 may absorb vibration energy between the tub 20 and the cabinet 10 to attenuate the vibration.

[0070] According to an embodiment, the drum 30 may perform a washing cycle of raising and dropping laundry while rotating inside the tub 20. A lifter 31 and / or a plurality of through-holes 32 may be provided in the inner circumferential surface of the drum 30. The lifter 31 may lift the laundry while the drum 30 rotates so that the laundry repeatedly rises and falls, thereby evenly washing laundry on several surfaces thereof. The through hole 32 may be a passage formed so that the water or washing water accommodated in the tub 20 flows into the drum 30 or the water or washing water inside the drum 30 is discharged to the outside.

[0071] According to an embodiment, the door 40 may be rotatably coupled to the front panel 11a of the cabinet 10. In an embodiment, the door 40 may rotate to open and close the opening 12 of the front panel 11a. In an embodiment, the door 40 may include a door frame 41 and a door glass 43. The door glass 43 may be formed of a transparent tempered glass material to see through the inside of the cabinet 10.

[0072] According to an embodiment, a control panel 50 including an input unit 51 for receiving an operation command of the washing machine 1 from the user and an output unit 52 for outputting operation information about the washing machine 1 may be disposed on the front surface of the cabinet 10. The input unit 51 may be implemented as an input means such as a dial switch as shown in the drawings, but the 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 the drawings, but the disclosure is not limited thereto.

[0073] According to an embodiment, the driving device 60 may be disposed behind the drum 30. In an embodiment, the driving device 60 may be provided to rotate the drum 30 by transferring the driving force generated by a motor 61 to the drum 30 through a rotation shaft 67. In an embodiment, the motor 61 may include a fixed stator 63 and a rotor 65 that rotates by electromagnetically interacting with the stator 63 to convert an electric force into a rotational force.

[0074] According to an embodiment, a spray nozzle 70 connected to a circulation hose 71 to spray the circulating mixed water into the drum 30 may be provided on one side of the diaphragm 17. In an embodiment, the spray nozzle 70 may be configured to evenly spray mixed water to the entire laundry accommodated in the drum 30. In an embodiment, the circulation hose 71 may be connected to a circulation pump 73 for pumping mixed water stored under the tub 20.

[0075] According to an embodiment, the detergent cartridge 100 may be disposed on the front upper portion of the tub 20. In an embodiment, the detergent cartridge 100 may be drawn into the washing machine 1 or withdrawn out of the washing machine 1 through the opening 90a of the detergent supply unit 90. In an embodiment, the detergent cartridge 100 may store a detergent for washing therein. The detergent may include a general detergent, a neutral detergent, a baby detergent, or a softener. In an embodiment, the detergent cartridge 100 may automatically supply detergent to the inside (e.g., the tub 20) of the washing machine 1 by interaction with a nozzle pressing device (not shown) when drawn in the detergent supply unit 90. The detergent cartridge 100 may also be referred to as an automatic detergent container.

[0076] FIG. 3 is a view schematically illustrating a PCM steel sheet for a home appliance according to an embodiment of the disclosure.

[0077] The PCM steel sheet 200 of FIG. 3 may constitute at least part of a plurality of panels (e.g., the plurality of panels 11 of FIGS. 1 and 2) of a cabinet (e.g., the cabinet 10 of FIGS. 1 and 2) of the washing machine 1 of FIGS. 1 and 2.

[0078] Referring to FIG. 3, the PCM steel sheet 200 may include steel sheet 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.

[0079] According to an embodiment, the steel sheet 210 may include an electro-galvanized iron (EGI) steel sheet or a galvanized iron (GI) steel sheet. However, the type of the steel sheet 210 is not limited thereto, and the type of the steel sheet 210 may vary depending on the purpose and function. For example, the steel sheet 210 may further include stainless steel or cold rolled steel sheet.

[0080] According to an embodiment, the chemical conversion coating layer 220 may be disposed on the steel sheet 210. The chemical conversion coating layer 220 may be disposed between the steel sheet 210 and the primer 230. The chemical conversion coating layer 220 may be obtained by performing chemical conversion treatment on the steel sheet 210 to secure corrosion resistance and interlayer adhesion of the steel sheet 210 after degreasing and rinsing the steel sheet 210. For example, the chemical conversion coating layer 220 may be provided in the form of chemical conversion coating by a process, such as phosphate treatment or chromate treatment.

[0081] According to an embodiment, the primer 230 may be disposed on the chemical conversion coating layer 220. The primer 230 may be provided to fix a paint (or coating) applied to the steel sheet 210. The primer 230 may be referred to as an adhesive layer. The primer 230 may include, e.g., a polyester resin. For example, the thickness of the primer 230 may be about 4 μm to 6 μm. For example, the thickness of the primer 230 may be about 5 um.

[0082] According to an embodiment, the base coating layer 240 may be disposed on the primer 230. The base coating layer 240 may include a main resin, a curing resin, a pigment, a defoamer, a leveling agent, and a solvent. For example, the thickness of the base coating layer 240 may be about 12 μm to 24 μm. For example, the thickness of the base coating layer 240 may be 15 μm to 20 μm.

[0083] Table 1 is a table illustrating the types and contents of the components 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 component is wt %.TABLE 1itemscomponentscontent (wt %)main resinpolyester resin50 to 70curing resinmelamine resin5 to 15pigmentmetallic pigment3 to 8colored pigment3 to 7defoamer and / oracrylic polymer1 to 5leveling agentsolventester-based thinner5 to 10ketone-based thinner5 to 10

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

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

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

[0087] According to an 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 wt % to 7 wt % of colored pigment.

[0088] According to an embodiment, the defoamer 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 wt % to 5 wt % of acrylic polymer.

[0089] According to an 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 wt % to 10 wt % of ester-based thinner. For example, the base coating layer 240 may include 5 wt % to 10 wt % of ketone-based thinner.

[0090] According to an 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 μm. For example, the thickness of the print layer 250 may be 1 to 2 μm.

[0091] According to an embodiment, the print layer 250 may be formed by a digital printing method. The digital printing method may directly print a high-resolution image on the steel sheet, and have a simplified process compared to a printing method using gravure roll, which is a conventional printing method. Further, the digital printing method may accurately reproduce complex patterns, images and / or text, and may be customized for various designs, which may be advantageous for small-scale production. The digital printing method may provide fast curing speed and excellent durability using, e.g., UV curing ink. The print layer 250 formed by the digital printing method may maintain a printed design for a long time by a strong adhesive force to the base coating layer 240.

[0092] According to an embodiment, the clear coating layer 260 may be disposed on the print layer 250. The clear coating layer 260 may be provided to give gloss to the surface of the PCM steel sheet 200 to enhance appearance. 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 outside the steel sheet 210 and the print layer 250 to protect the steel sheet 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 μm to 12 μm. For example, the thickness of the clear coating layer 260 may be about 10 um.

[0093] According to an embodiment, the clear coating layer 260 may include a main resin, a curing resin, a defoamer, a leveling agent, and a solvent.

[0094] Table 2 is a table illustrating the types and contents of the components constituting the clear coating layer 260. In addition to the components shown in Table 2, various substances may be included in the clear coating layer 260. The unit of each component is wt %.TABLE 2itemscomponentscontent (wt %)main resinpolyester resin60 to 75curing resinmelamine resin10 to 20defoamer and / oracrylic polymer1 to 5leveling agentsolventester-based thinner5 to 15ketone-based thinner5 to 15

[0095] Referring to Table 2, the main resin of the clear coating layer 260 according to an embodiment may include a polyester resin. For example, the clear coating layer 260 may include 60 wt % to 75 wt % of polyester resin relative to the total weight.

[0096] According to an embodiment, the curing resin of the clear coating layer 260 may include a melamine resin. For example, the clear coating layer 260 may include 10 wt % to 20 wt % of melamine resin relative to the total weight.

[0097] According to an embodiment, the defoamer and / or leveling agent of the clear coating layer 260 may include an acrylic polymer. For example, the clear coating layer 260 may include 1 wt % to 5 wt % of acrylic pigment.

[0098] According to an 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 wt % to 15 wt % of ester-based thinner. For example, the clear coating layer 260 may include 5 wt % to 15 wt % of ketone-based thinner.

[0099] According to an embodiment, an adhesive layer may be provided between the print layer 250 and the clear coating layer 260. The adhesive layer may include a UV adhesive that is rapidly cured through ultraviolet curing, but is not limited thereto. The adhesive layer may be omitted from the configuration of the PCM steel sheet 200.

[0100] FIG. 4 is a graph illustrating the gloss, processability, and hardness according to the molecular weight of a polyester resin of a clear coating layer according to an embodiment of the disclosure.

[0101] According to an embodiment, the clear coating layer 260 of the PCM steel sheet 200 may include a polyester resin as the main resin.

[0102] For the PCM steel sheet used for the cabinet (e.g., the front panel 11a) of the washing machine 1, a polyester resin having a high-molecular weight (e.g., a polyester resin of 10,000 to 30,000 Mw) is used to ensure moldability. As its molecular weight increases, the polyester resin increases the elongation of the coating film, which may increase the moldability of the PCM steel sheet. However, as the molecular weight of 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. As the molecular weight of polyester increases, the hardness (scratch resistance) of the PCM steel sheet may decrease. For these reasons, the PCM steel sheet may have inferior appearance quality compared to the VCM steel sheet. Accordingly, there is a need to develop PCM steel sheets that have the same appearance quality and hardness as the VCM steel sheet.

[0103] The composition of the PCM steel sheet 200 to secure the appearance quality and hardness of the PCM steel sheet is described below.

[0104] Table 3 is a table illustrating the results of gloss, distinctness of reflective image (DOI), moldability test, and surface hardness of the clear coating layer 260 according to the molecular weight of the polyester resin of 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 sheet was bent to bring the portions into contact with each other. Here, as the gloss, the amount of reflected light when light is incident on the surface at an angle of 20 degrees was measured using a gloss meter.TABLE 3molecular weight (Mw)5000 to 80008000 to 1200020000 to 2500020° gloss (GU)91.282.180.3distinctness of47.141.739.4reflective image(DOI)bending test (0 T)no crackno crackno crackcupping testcrackno crackno crackimpact testwhiteningno whiteningno whiteningpress testwhiteningno whiteningno whiteningsurface hardnessFHB2B to B

[0105] Referring to Table 3, when the molecular weight of the polyester resin of the clear coating layer 260 is 5000 to 8000 Mw, it may be identified that the clear coating layer 260 has a gloss of 91.2 gloss units (GU) and a distinctness of image (DOI) of 47.1. Further, it may be identified that cracks and whitening occur in the moldability test of the clear coating layer 260 except for the bending test. Further, it may be identified that the hardness of the clear coating layer 260 is F.

[0106] When the molecular weight of the polyester resin of the clear coating layer 260 is 8000 to 12000 Mw, it may be identified that the clear coating layer 260 has a gloss of 82.1 GU and a DOI of 41.7. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0107] When the molecular weight of the polyester resin of the clear coating layer 260 is 20000 to 25000 Mw, it may be identified that the clear coating layer 260 has a gloss of 80.3 GU and a DOI of 39.4. Further, it may be identified that cracks and whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is 2B to B.

[0108] Referring to FIG. 4 based on the data values in Table 3, it may be identified again that as the molecular weight of the polyester resin included in the clear coating layer 260 increases, the moldability is good, but the gloss, DOI, and surface hardness decrease.

[0109] As a result, the clear coating layer 260 may 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.

[0110] According to an embodiment, the clear coating layer 260 may include a polyester resin and an acrylic resin. The acrylic resin is an amorphous resin and has low light scattering and high transparency due to its structural and optical properties. When an acrylic resin is included in the clear coating layer 260, the gloss of the clear coating layer 260 may be enhanced by the physical properties of the acrylic resin.

[0111] Table 4 is a table illustrating the gloss, moldability, and surface hardness according to the ratio of polyester resin and acrylic resin in the clear coating layer 260.TABLE 4polyester:acrylic100:095:590:1085:1580:20gloss82.185.586.086.886.5bending testno crackno crackno crackno crackno crack(0 T)impact testnononowhiteningwhiteningwhiteningwhiteningwhiteningsurfaceBHBHBHBFhardness

[0112] 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 may be identified that the gloss of the clear coating layer 260 has a value of 82.1 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is B.

[0113] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 95 to 5, it may be identified that the gloss of the clear coating layer 260 has a value of 85.5 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0114] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 90 to 10, it may be identified that the gloss of the clear coating layer 260 has a value of 86.0 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0115] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 85 to 15, it may be identified that the gloss of the clear coating layer 260 has a value of 86.8 GU. Further, it may be identified that cracks do not occur in the moldability test of the clear coating layer 260. But it may be identified whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0116] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 80 to 20, it may be identified that the gloss of the clear coating layer 260 has a value of 86.5 GU. Further, it may be identified that cracks do not occur in the moldability test of the clear coating layer 260. But it may be identified that whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is F.

[0117] It may be identified that as the content proportion of acrylic resin relative to polyester resin increases, the gloss increases, but the gloss converges when the proportion of acrylic resin is 15% or more. Further, it may be identified that a hardness of HB or higher is secured when the proportion of acrylic resin is 5% or higher. However, it may be identified that the moldability is not secured as whitening occur when the proportion of acrylic resin exceeds 15%.

[0118] As a result, the clear coating layer 260 may secure a gloss of about 85.5 GU to 86.0 GU, moldability, and a hardness of HB or higher when the proportion of the acrylic resin relative to the polyester resin is 5 to 10%.

[0119] FIG. 5 is a graph illustrating the distinctness of image (DOI) and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure.

[0120] FIG. 6 is a graph illustrating the distinctness of image (DOI) and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure.

[0121] According to an embodiment, the base coating layer 240 of the PCM steel sheet 200 may include a metallic pigment. In an embodiment, the metallic pigment of the base coating layer 240 may include aluminum paste. The aluminum paste may be used to enhance the gloss and / or luminance of the PCM steel sheet 200 by utilizing the mirror effect. However, in the case of PCM steel sheets, as the particle size of the pigment increases, the surface roughness increases, which may reduce the gloss and / or distinctness of image (DOI).

[0122] Referring to FIGS. 5 and 6, in the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 61.8 and a luminance of 9.12 candela per square meter (cd / m2) when the particle size of the aluminum paste is 12 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 53.6 and a luminance of 9.42 cd / m2 when the particle size of the aluminum paste is 19 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 50.5 and a luminance of 9.34 cd / m2 when the particle size of the aluminum paste is 23 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 42 and a luminance of 11.2 cd / m2 when the particle size of the aluminum paste is 32 μm.

[0123] In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 56.5 and a luminance of 9.31 cd / m2 when the particle size of the aluminum paste is 12 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 46.7 and a luminance of 10.9 cd / m2 when the particle size of the aluminum paste is 19 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 34.6 and a luminance of 10.46 cd / m2 when the particle size of the aluminum paste is 23 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 24.4 and a luminance of 12.46 cd / m2 when the particle size of the aluminum paste is 32 μm.

[0124] As a result, as the particle size of the aluminum paste decreases, the density of particles per unit area increases, which may increase the DOI. As the size of the aluminum paste increases, the interference between particles decreases, which may decrease diffuse reflection, leading to higher luminance. However, it may be identified that the difference in luminance is insignificant, as compared with the DOI, according to changes in particle size.

[0125] FIG. 7 is a graph illustrating the gloss, the distinctness of image (DOI), and luminance according to the particle size, per particle shape, of an aluminum paste according to an embodiment of the disclosure.

[0126] According to an embodiment, in the base coating layer 240, the aluminum paste, which is a metallic pigment, may have various forms. For example, the aluminum paste may have the form of cornflakes (or flakes) or silver dollars. The aluminum paste in the form of cornflakes may be referred to as aluminum flakes.

[0127] Referring to FIG. 7, in the case of aluminum paste in the form of cornflakes, when the content of aluminum paste is 12 wt % and the particle size is 10 to 12 μm, the gloss may have a value of 94.3 GU, the distinctness of image (DOI) may have a value of 57.7, and the luminance (F.I) may have a value of 10.11 cd / m2. When the content of aluminum paste is 6 wt % and the particle size is 19 to 21 μm, the gloss may have a value of 84.9 GU, the distinctness of image (DOI) may have a value of 44.5, and the luminance (F.I) may have a value of 12.9 cd / m2. When the content of aluminum paste is 2.5 to 3 wt % and the particle size is 30 to 32 μm, the gloss may have a value of 74.8 GU, the distinctness of image (DOI) may have a value of 33.4, and the luminance (F.I) may have a value of 11.23 cd / m2.

[0128] In the case of aluminum paste in the form of silver dollar, when the content of aluminum paste is 12 wt % and the particle size is 10 to 12 μm, the gloss may have a value of 94.5 GU, the distinctness of image (DOI) may have a value of 57.3, and the luminance (F.I) may have a value of 11.23 cd / m2. When the content of aluminum paste is 6 wt % and the particle size is 19 to 21 μm, the gloss may have a value of 84.6 GU, the distinctness of image (DOI) may have a value of 43.7, and the luminance (F.I) may have a value of 11.64 cd / m2. When the content of aluminum paste is 2.5 to 3 wt % and the particle size is 30 to 32 μm, the gloss may have a value of 64.3 GU, the distinctness of image (DOI) may have a value of 16.4, and the luminance (F.I) may have a value of 11.17 cd / m2.

[0129] In the case of aluminum paste in the form of silver dollar, as the shape of the particles is rounded and regular, the circumferential length is shorter in relation to the surface area compared to aluminum paste in the form of irregular cornflake structure, which may reduce light scattering.

[0130] As a result, the aluminum paste in the form of silver dollar may secure high luminance (e.g., a luminance of 9 cd / m2 or more) while ensuring gloss and DOI even when it has a small particle size of 10 to 12 μm.

[0131] A PCM steel sheet 200 for a home appliance according to an embodiment of the disclosure may comprise a steel sheet 210, a chemical conversion coating layer 220 disposed on the steel sheet 210, a primer 230 disposed on the chemical conversion coating 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. An average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0132] According to an embodiment, the clear coating layer 260 may further include an acrylic resin.

[0133] According to an embodiment, a content proportion of the acrylic resin relative to the polyester resin may be 5% to 10%.

[0134] According to an embodiment, a pigment of the base coating layer 240 may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0135] According to an embodiment, the aluminum paste may have particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

[0136] According to an embodiment, the particles may have a particle size of 10 μm to 20 μm.

[0137] According to an embodiment, the clear coating layer may have a surface hardness of HB or more.

[0138] According to an embodiment, the clear coating layer may have a 20-degree gloss of 80GU or more.

[0139] According to an embodiment, the clear coating layer may have a distinctness of image of 40 or more.

[0140] According to an embodiment, the clear coating layer may have a luminance of 9 cd / m2 or more.

[0141] A washing machine 1 according to an embodiment of the disclosure may comprise a casing 10 including a plurality of panels 11, a tub 20 disposed in the casing 10, and a drum 30 in the tub 20 and configured to rotate in the tub 20. The plurality of panels 11 may include a PCM steel sheet 200. The PCM steel sheet 200 may comprise a steel sheet 210, a chemical conversion coating layer 220 disposed on the steel sheet 210, a primer 230 disposed on the chemical conversion coating 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. An average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0142] According to an embodiment, the clear coating layer 260 may further include an acrylic resin.

[0143] According to an embodiment, a content proportion of the acrylic resin relative to the polyester resin may be 5% to 10%.

[0144] According to an embodiment, a pigment of the base coating layer 240 may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0145] According to an embodiment, the aluminum paste may have particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

[0146] According to an embodiment, the particles may have a particle size of 10 μm to 20 μm.

[0147] According to an embodiment, the clear coating layer may have a surface hardness of HB or more.

[0148] According to an embodiment, the clear coating layer may have a 20-degree gloss of 80GU or more.

[0149] According to an embodiment, the clear coating layer may have a distinctness of image of 40 or more.

[0150] According to an embodiment, the clear coating layer may have a luminance of 9 cd / m2 or more.

[0151] In the disclosure, the above-described description has been made mainly of specific embodiments, but the disclosure is not limited to such specific embodiments, but should rather be appreciated as covering all various modifications, equivalents, and / or substitutes of various embodiments.

Examples

Embodiment Construction

[0017]It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment.

[0018]With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements.

[0019]It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise.

[0020]As used herein, each of such phrases as “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 all possible combinations of the items enumerated together in a corresponding one of the phrases.

[0021]The term “and / or” may denote a combination(s) of a plurality of related components as listed or any...

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application is a continuation of an International application No. PCT / KR2025 / 007251 designating the United States, filed on May 28, 2025, in the Korean Intellectual Property Receiving Office, which claims priority from Korean Patent Application No. 10-2024-0107070, filed on Aug. 9, 2024, in the Korean Intellectual Property Office, the disclosures of each of which are incorporated by reference herein in their entireties.TECHNICAL FIELD

[0002] Various embodiments of the disclosure relate to a pre-coated metal (PCM) steel sheet and a washing machine including the same.BACKGROUND ART

[0003] Home appliances, such as washing machines, may include a steel sheet for implementing the exterior. Pre-coated metal (PCM) steel sheets or vinyl-coated metal (VCM) steel sheets may be adopted as such steel sheets. To implement various patterns to suit the needs of consumers, it may be appropriate to use VCM steel sheets, which are high-gloss and high-DOI steel sheets, instead of PCM steel sheets. However, use of VCM steel plates may increase the production costs.

[0004] The above-described information may be provided as related art for the purpose of helping understanding of the disclosure. No claim or determination is made as to whether any of the foregoing is applicable as background art in relation to the disclosure.DISCLOSURE OF INVENTIONSolution to Problems

[0005] Various embodiments of the disclosure may implement high gloss, high DOI, or high luminance at the level of the VCM by adopting a digital printing method and adjusting the composition the coating layer.

[0006] In accordance with the present disclosure, a pre-coated metal (PCM) steel sheet for a home appliance may include: a steel sheet; a chemical conversion coating layer on the steel sheet; a primer on the chemical conversion coating layer; a base coating layer on the primer, the base coating layer including a pigment; a print layer on the base coating layer; and a clear coating layer on the print layer, the clear coating layer including a polyester resin, wherein an average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0007] In accordance with the present disclosure, a washing machine may include: a casing including a plurality of panels; a tub in the casing; and a drum in the tub, the drum configured to rotate in the tub, wherein the plurality of panels may include a pre-coated metal (PCM) steel sheet, and the PCM steel sheet may include: a steel sheet, a chemical conversion coating layer on the steel sheet, a primer on the chemical conversion coating layer, a base coating layer on the primer, the base coating layer including a pigment, a print layer on the base coating layer, and a clear coating layer on the print layer, the clear coating layer including a polyester resin, and average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0008] The disclosure is not limited to the foregoing embodiments but various modifications or changes may rather be made thereto without departing from the spirit and scope of the disclosure.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a perspective view illustrating a washing machine according to an embodiment;

[0010] FIG. 2 is a cross-sectional view illustrating a washing machine according to an embodiment;

[0011] FIG. 3 is a view schematically illustrating a PCM steel sheet for a home appliance according to an embodiment;

[0012] FIG. 4 is a graph illustrating the gloss, processability, and hardness according to the molecular weight of a polyester resin of a clear coating layer according to an embodiment of the disclosure;

[0013] FIG. 5 is a graph illustrating the DOI and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure;

[0014] FIG. 6 is a graph illustrating the DOI and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure; and

[0015] FIG. 7 is a graph illustrating the gloss, DOI, and luminance according to the particle size, per particle shape, of an aluminum paste according to an embodiment of the disclosure.

[0016] Reference may be made to the accompanying drawings in the following description, and specific examples that may be practiced are shown as examples within the drawings. Other examples may be utilized and structural changes may be made without departing from the scope of the various examples.MODE FOR THE INVENTION

[0017] It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment.

[0018] With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements.

[0019] It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise.

[0020] As used herein, each of such phrases as “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 all possible combinations of the items enumerated together in a corresponding one of the phrases.

[0021] The term “and / or” may denote a combination(s) of a plurality of related components as listed or any of the components.

[0022] As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order).

[0023] As used herein, the terms ‘front surface,’‘rear surface,’‘upper surface,’‘side surface,’‘left side,’‘right side,’‘upper portion,’ and ‘lower portion’ are defined with respect to the drawings, and the shape and position of each component are not limited by the terms.

[0024] It will be further understood that the terms “comprise” and / or “have,” as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] It will be understood that when a component is referred to as “connected to,”“coupled to”, “supported on,” or “contacting” another component, the components may be connected to, coupled to, supported on, or contact each other directly or via a third component.

[0026] Throughout the specification, when one component is positioned “on” another component, the first component may be positioned directly on the second component, or other component(s) may be positioned between the first and second component.

[0027] A home appliance according to various embodiments may include a clothing treatment device. The washing machine, which is a clothing treatment device, may perform washing, rinsing, spinning, and drying cycles. The washing machine is an example of the clothing treatment device. The clothing treatment device encompasses devices for washing clothes (objects to be washed or objects to be dried), devices for drying clothes, and devices capable of performing both washing and drying of clothes.

[0028] The washing machine according to various embodiments may include a top-loading washing machine in which a laundry inlet for inserting or withdrawing laundry faces upward, or a front-loading washing machine in which a laundry inlet faces forward. The washing machine according to various embodiments may include a washing machine having various loading schemes other than the top-loading and front-loading washing machines described above.

[0029] The top-loading washing machine may wash laundry using a water flow generated by a rotating body such as a pulsator. The front-loading washing machine may wash laundry by repeatedly raising and dropping the laundry by rotating the drum. The front-loading washing machine may include a dryer cum washing machine capable of drying laundry accommodated in the drum. The dryer cum washing machine may include a hot air supply device for supplying high-temperature air into the drum and a condensation device for removing moisture from the air discharged from the drum. For example, the dryer cum washing machine may include a heat pump device. The washing machine according to various embodiments may include a washing machine of a washing method other than the above-described washing method.

[0030] The washing machine according to various embodiments may include a housing accommodating various components therein. The housing may be provided in the form of a box having a laundry inlet formed in one side thereof.

[0031] The washing machine may include a door for opening and closing the laundry inlet. The door may be rotatably mounted on the housing by a hinge. At least a portion of the door may be provided to be transparent or translucent so that the inside of the housing is visible.

[0032] The washing machine may include a tub provided inside the housing to store water. The tub may be provided in a substantially cylindrical shape with a tub opening formed in one side thereof, and may be disposed inside the housing so that the tub opening is disposed to correspond to the laundry inlet.

[0033] The tub may be connected to the housing by a damper. The damper may absorb vibrations generated when the drum rotates and attenuate vibrations transferred to the housing.

[0034] The washing machine may include a drum provided to accommodate laundry.

[0035] The drum may be disposed inside the tub so that a drum opening provided in one side corresponds to the laundry inlet and the tub opening. The laundry may be accommodated in the drum or withdrawn from the drum by sequentially passing through the laundry inlet, the tub opening, and the drum opening.

[0036] The drum may perform each operation according to washing, rinsing, and / or spinning cycles while rotating inside the tub. A plurality of through holes may be formed in the cylindrical wall of the drum to allow water stored in the tub to flow into or out of the drum.

[0037] The washing machine may include a driving device configured to rotate the drum. The driving device may include a driving motor and a rotation shaft for transferring the driving force generated by the driving motor to the drum. The rotating shaft may be connected to the drum through the tub.

[0038] The driving device may perform each operation according to washing, rinsing, and / or spinning, or drying cycle by rotating the drum forward or backward.

[0039] The washing machine may include a water supply device configured to supply water to the tub. The water supply device may include a water supply pipe and a water supply valve provided in the water supply pipe. The water supply pipe may be connected to an external water supply source. The water supply pipe may extend from an external water supply source to the 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.

[0040] The water supply valve may open or close the water supply pipe in response to an electrical signal from the controller. The water supply valve may allow or block water from being supplied from an external water supply source to the tub. The water supply valve may include, e.g., a solenoid valve that is opened and closed in response to an electrical signal.

[0041] The washing machine may include a detergent supply device configured to supply detergent to the tub. The detergent supply device may include a manual detergent supply device in which the user needs to put a detergent to be used for each washing, and an automatic detergent supply device in which a large amount of detergent is stored and a predetermined amount of detergent is automatically put into the washing. The detergent supply device may include a detergent container for storing the detergent. The detergent supply device may be configured to supply detergent into the tub during a water supply process. Water supplied through the water supply pipe may be mixed with the detergent via the detergent supply device. Water mixed with the detergent may be supplied into the tub. Detergent is used as a term encompassing a detergent for pre-washing, a detergent for main washing, a fabric softener, a bleach, or the like, and the detergent container may be divided into a pre-washing detergent storage area, a main washing detergent storage area, a fabric softener storage area, and a bleach storage area.

[0042] The washing machine may include a drain device configured to discharge water contained in the tub to the outside. The drain device may include a drain pipe extending from a lower portion 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 from the drain pipe to the outside of the housing.

[0043] The washing machine may include a control panel disposed on one side surface of the housing. The control panel may provide a user interface for the user and the washing machine to interact with each other. The user interface may include at least one input interface and at least one output interface.

[0044] At least one input interface may convert sensory information received from the user into an electrical signal.

[0045] The at least one input interface may include a power button, an operation button, a course selection dial (or a course selection button), and a washing / rinsing / spinning setting button. The at least one input interface may include, e.g., 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.

[0046] The at least one output interface may visually or audibly transfer information related to the operation of the washing machine to the user.

[0047] For example, the at least one output interface may transfer information related to the washing course, the operation time of the washing machine, and the washing setting / rinsing setting / spinning setting to the user. The information about the operation of the washing machine may be output as a screen, an indicator, a voice, etc. The at least one output interface may include, e.g., a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, a speaker, or the like.

[0048] The washing machine may include a communication module for wired and / or wireless communication with an external device.

[0049] The communication module may include at least one of a short-range communication module or a long-range communication module.

[0050] The communication module may transmit data to an external device (e.g., a server, a user device, and / or a home appliance) or may receive data from the external device. For example, the communication module may establish communication with a server and / or the user device and / or a home appliance, and transmit and receive various data.

[0051] To that end, the communication module may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between external devices and performing communication through the established communication channel. According to an 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 (PLC) module). A corresponding one 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 (Wi-Fi) 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., local area network (LAN) or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other.

[0052] The short-range wireless communication module may include, but is not limited to, a Bluetooth communication module, a BLE communication module, a near field communication module, a WLAN (Wi-Fi) communication module, a Zigbee communication module, an infrared data association (IrDA) communication module, a Wi-Fi direct (WFD) communication module, an ultrawideband (UWB) communication module, an Ant+ communication module, and a microwave (uWave) communication module.

[0053] The long-range communication module may include a communication module that performs various types of long-range communication, and may include a mobile communication unit. The mobile communication unit transmits and receives a wireless signal to and from at least one of a base station, an external terminal, and a server over a mobile communication network.

[0054] In an embodiment, the communication module may communicate with an external device such as a server, a user equipment, another home appliance, or the like through an access point (AP). The AP may connect the local area network (LAN) to which the washing machine or the user equipment is connected to the wide area network (WAN) to which the server is connected. The washing machine or the user device may be connected to the server through the wide area network (WAN). The controller may control various components (e.g., a driving motor and a water supply valve) of the washing machine. The controller may control various components of the washing machine to perform at least one cycle including water supply, washing, rinsing, and / or spinning according to the user input. For example, the controller may control the driving motor to adjust the rotational speed of the drum, or control the water supply valve of the water supply device to supply water to the tub.

[0055] The controller may include hardware such as a CPU or a memory, and software such as a control program. For example, the controller may include an algorithm for controlling operations of the components in the washing machine, at least one memory for storing data in the form of a program, and at least one processor for performing the above-described operations using the data stored in the at least one memory. The memory and the processor may be implemented as separate chips, respectively. The processor may include one or more processor chips or may include one or more processing cores. The memory may include one or more memory chips or may include one or more memory blocks. Further, the memory and the processor may be implemented as a single chip.

[0056] FIG. 1 is a perspective view illustrating a washing machine according to an embodiment of the disclosure;

[0057] FIG. 2 is a cross-sectional view illustrating a washing machine according to an embodiment of the disclosure.

[0058] Specifically, FIG. 1 is a perspective view illustrating a state in which a door 40 of a washing machine 1 according to an embodiment is opened.

[0059] Referring to FIGS. 1 and 2, a washing machine 1 according to an embodiment may include a cabinet 10 forming an outer appearance and accommodating various components therein, a tub 20 provided inside the cabinet 10 to store mixed water in which water and detergent are mixed, 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 rotating the drum 30, a detergent supply unit 90 for supplying the detergent to the tub 20, and a detergent cartridge 100 provided to be drawn in / out the detergent supply unit 90.

[0060] According to an embodiment, the cabinet 10 may have a hexahedral shape as a whole. In an embodiment, the cabinet 10 may be formed in a box shape with an open front.

[0061] According to an embodiment, the cabinet 10 may include a plurality of panels 11. According to an embodiment, at least one of the plurality of panels 11 may include a PCM steel sheet (e.g., the PCM steel sheet 200 of FIG. 3) to be described below. The cabinet 10 may include a front panel 11a provided in the open front (e.g., the +x-axis direction), side panels 11b and 11c disposed on two opposite side surfaces (e.g., the surfaces facing in the ±y-axis directions) rearward of the front panel 11a, a rear panel 11d provided at the rear (e.g., the −x-axis direction) of the cabinet 10, and a top cover 11e provided on an upper surface (e.g., the surface facing in the +z-axis direction) thereof. An example in which in the cabinet 10, the rear panel 11d and two opposite side panels 11b and 11c are integrally formed is illustrated, but the disclosure is not limited thereto.

[0062] According to an embodiment, an opening 12 may be formed in the front panel 11a to allow laundry to be put into the drum 30. Openings may be formed in the tub 20 and the drum 30 to allow laundry to be put in or out 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.

[0063] According to an embodiment, the cabinet 10 may include a base 13 provided at the bottom. In an embodiment, the base 13 may include a lower frame 13a formed to cover a lower portion of the cabinet 10 and a lower reinforcing frame 13b formed to extend from the lower frame 13a.

[0064] According to an embodiment, a water supply device 14 including a water supply pipe 14a for supplying washing water to the detergent supply unit 90 and / or the tub 20, and a water supply valve 14b for controlling water supply of the water supply pipe 14a may be provided above the tub 20. Further, the water supply device 14 may further include a water supply nozzle (not shown) for jetting washing water into the detergent supply unit 90. The water supply device 14 may be referred to as a water supply unit.

[0065] According to an embodiment, the detergent supply unit 90 having an opening (or inlet) 90a through which the detergent cartridge 100 is drawn in / out may be provided above the tub 20. In an embodiment, a cover 15 may be provided in the front of the washing machine 1 to open / close the opening 90a. The cover 15 may be rotatably connected to the front surface (e.g., the front panel 11a) of the washing machine 1.

[0066] According to an embodiment, the detergent supply unit 90 may be connected to the water supply pipe 14a from the rear. In an embodiment, the detergent supply unit 90 may be connected to an upper portion of the tub 20 through a supply pipe 16. The water supplied through the water supply pipe 14a may be mixed with the detergent via the detergent supply device 90 through the water supply nozzle (not shown), and the mixed water in which the water and the detergent are mixed may be supplied into the tub 20 through the supply pipe 16.

[0067] According to an 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.

[0068] According to an embodiment, the tub 20 may store mixed water in which water and a detergent are mixed. The tub 20 may be formed in a cylindrical shape as a whole. In an embodiment, the tub 20 may be fixed inside the cabinet 10. Although not specifically shown in the drawings, a drain 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 under the tub 20. The drain device may be referred to as a drain unit.

[0069] According to an embodiment, the tub 20 may be provided to be elastically supported from the cabinet 10 by an upper spring (not shown) and lower dampers 80. When vibration generated when the drum 30 rotates is transferred to the tub 20 and the cabinet 10, the spring and dampers 80 may absorb vibration energy between the tub 20 and the cabinet 10 to attenuate the vibration.

[0070] According to an embodiment, the drum 30 may perform a washing cycle of raising and dropping laundry while rotating inside the tub 20. A lifter 31 and / or a plurality of through-holes 32 may be provided in the inner circumferential surface of the drum 30. The lifter 31 may lift the laundry while the drum 30 rotates so that the laundry repeatedly rises and falls, thereby evenly washing laundry on several surfaces thereof. The through hole 32 may be a passage formed so that the water or washing water accommodated in the tub 20 flows into the drum 30 or the water or washing water inside the drum 30 is discharged to the outside.

[0071] According to an embodiment, the door 40 may be rotatably coupled to the front panel 11a of the cabinet 10. In an embodiment, the door 40 may rotate to open and close the opening 12 of the front panel 11a. In an embodiment, the door 40 may include a door frame 41 and a door glass 43. The door glass 43 may be formed of a transparent tempered glass material to see through the inside of the cabinet 10.

[0072] According to an embodiment, a control panel 50 including an input unit 51 for receiving an operation command of the washing machine 1 from the user and an output unit 52 for outputting operation information about the washing machine 1 may be disposed on the front surface of the cabinet 10. The input unit 51 may be implemented as an input means such as a dial switch as shown in the drawings, but the 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 the drawings, but the disclosure is not limited thereto.

[0073] According to an embodiment, the driving device 60 may be disposed behind the drum 30. In an embodiment, the driving device 60 may be provided to rotate the drum 30 by transferring the driving force generated by a motor 61 to the drum 30 through a rotation shaft 67. In an embodiment, the motor 61 may include a fixed stator 63 and a rotor 65 that rotates by electromagnetically interacting with the stator 63 to convert an electric force into a rotational force.

[0074] According to an embodiment, a spray nozzle 70 connected to a circulation hose 71 to spray the circulating mixed water into the drum 30 may be provided on one side of the diaphragm 17. In an embodiment, the spray nozzle 70 may be configured to evenly spray mixed water to the entire laundry accommodated in the drum 30. In an embodiment, the circulation hose 71 may be connected to a circulation pump 73 for pumping mixed water stored under the tub 20.

[0075] According to an embodiment, the detergent cartridge 100 may be disposed on the front upper portion of the tub 20. In an embodiment, the detergent cartridge 100 may be drawn into the washing machine 1 or withdrawn out of the washing machine 1 through the opening 90a of the detergent supply unit 90. In an embodiment, the detergent cartridge 100 may store a detergent for washing therein. The detergent may include a general detergent, a neutral detergent, a baby detergent, or a softener. In an embodiment, the detergent cartridge 100 may automatically supply detergent to the inside (e.g., the tub 20) of the washing machine 1 by interaction with a nozzle pressing device (not shown) when drawn in the detergent supply unit 90. The detergent cartridge 100 may also be referred to as an automatic detergent container.

[0076] FIG. 3 is a view schematically illustrating a PCM steel sheet for a home appliance according to an embodiment of the disclosure.

[0077] The PCM steel sheet 200 of FIG. 3 may constitute at least part of a plurality of panels (e.g., the plurality of panels 11 of FIGS. 1 and 2) of a cabinet (e.g., the cabinet 10 of FIGS. 1 and 2) of the washing machine 1 of FIGS. 1 and 2.

[0078] Referring to FIG. 3, the PCM steel sheet 200 may include steel sheet 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.

[0079] According to an embodiment, the steel sheet 210 may include an electro-galvanized iron (EGI) steel sheet or a galvanized iron (GI) steel sheet. However, the type of the steel sheet 210 is not limited thereto, and the type of the steel sheet 210 may vary depending on the purpose and function. For example, the steel sheet 210 may further include stainless steel or cold rolled steel sheet.

[0080] According to an embodiment, the chemical conversion coating layer 220 may be disposed on the steel sheet 210. The chemical conversion coating layer 220 may be disposed between the steel sheet 210 and the primer 230. The chemical conversion coating layer 220 may be obtained by performing chemical conversion treatment on the steel sheet 210 to secure corrosion resistance and interlayer adhesion of the steel sheet 210 after degreasing and rinsing the steel sheet 210. For example, the chemical conversion coating layer 220 may be provided in the form of chemical conversion coating by a process, such as phosphate treatment or chromate treatment.

[0081] According to an embodiment, the primer 230 may be disposed on the chemical conversion coating layer 220. The primer 230 may be provided to fix a paint (or coating) applied to the steel sheet 210. The primer 230 may be referred to as an adhesive layer. The primer 230 may include, e.g., a polyester resin. For example, the thickness of the primer 230 may be about 4 μm to 6 μm. For example, the thickness of the primer 230 may be about 5 um.

[0082] According to an embodiment, the base coating layer 240 may be disposed on the primer 230. The base coating layer 240 may include a main resin, a curing resin, a pigment, a defoamer, a leveling agent, and a solvent. For example, the thickness of the base coating layer 240 may be about 12 μm to 24 μm. For example, the thickness of the base coating layer 240 may be 15 μm to 20 μm.

[0083] Table 1 is a table illustrating the types and contents of the components 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 component is wt %.TABLE 1itemscomponentscontent (wt %)main resinpolyester resin50 to 70curing resinmelamine resin5 to 15pigmentmetallic pigment3 to 8colored pigment3 to 7defoamer and / oracrylic polymer1 to 5leveling agentsolventester-based thinner5 to 10ketone-based thinner5 to 10

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

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

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

[0087] According to an 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 wt % to 7 wt % of colored pigment.

[0088] According to an embodiment, the defoamer 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 wt % to 5 wt % of acrylic polymer.

[0089] According to an 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 wt % to 10 wt % of ester-based thinner. For example, the base coating layer 240 may include 5 wt % to 10 wt % of ketone-based thinner.

[0090] According to an 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 μm. For example, the thickness of the print layer 250 may be 1 to 2 μm.

[0091] According to an embodiment, the print layer 250 may be formed by a digital printing method. The digital printing method may directly print a high-resolution image on the steel sheet, and have a simplified process compared to a printing method using gravure roll, which is a conventional printing method. Further, the digital printing method may accurately reproduce complex patterns, images and / or text, and may be customized for various designs, which may be advantageous for small-scale production. The digital printing method may provide fast curing speed and excellent durability using, e.g., UV curing ink. The print layer 250 formed by the digital printing method may maintain a printed design for a long time by a strong adhesive force to the base coating layer 240.

[0092] According to an embodiment, the clear coating layer 260 may be disposed on the print layer 250. The clear coating layer 260 may be provided to give gloss to the surface of the PCM steel sheet 200 to enhance appearance. 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 outside the steel sheet 210 and the print layer 250 to protect the steel sheet 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 μm to 12 μm. For example, the thickness of the clear coating layer 260 may be about 10 um.

[0093] According to an embodiment, the clear coating layer 260 may include a main resin, a curing resin, a defoamer, a leveling agent, and a solvent.

[0094] Table 2 is a table illustrating the types and contents of the components constituting the clear coating layer 260. In addition to the components shown in Table 2, various substances may be included in the clear coating layer 260. The unit of each component is wt %.TABLE 2itemscomponentscontent (wt %)main resinpolyester resin60 to 75curing resinmelamine resin10 to 20defoamer and / oracrylic polymer1 to 5leveling agentsolventester-based thinner5 to 15ketone-based thinner5 to 15

[0095] Referring to Table 2, the main resin of the clear coating layer 260 according to an embodiment may include a polyester resin. For example, the clear coating layer 260 may include 60 wt % to 75 wt % of polyester resin relative to the total weight.

[0096] According to an embodiment, the curing resin of the clear coating layer 260 may include a melamine resin. For example, the clear coating layer 260 may include 10 wt % to 20 wt % of melamine resin relative to the total weight.

[0097] According to an embodiment, the defoamer and / or leveling agent of the clear coating layer 260 may include an acrylic polymer. For example, the clear coating layer 260 may include 1 wt % to 5 wt % of acrylic pigment.

[0098] According to an 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 wt % to 15 wt % of ester-based thinner. For example, the clear coating layer 260 may include 5 wt % to 15 wt % of ketone-based thinner.

[0099] According to an embodiment, an adhesive layer may be provided between the print layer 250 and the clear coating layer 260. The adhesive layer may include a UV adhesive that is rapidly cured through ultraviolet curing, but is not limited thereto. The adhesive layer may be omitted from the configuration of the PCM steel sheet 200.

[0100] FIG. 4 is a graph illustrating the gloss, processability, and hardness according to the molecular weight of a polyester resin of a clear coating layer according to an embodiment of the disclosure.

[0101] According to an embodiment, the clear coating layer 260 of the PCM steel sheet 200 may include a polyester resin as the main resin.

[0102] For the PCM steel sheet used for the cabinet (e.g., the front panel 11a) of the washing machine 1, a polyester resin having a high-molecular weight (e.g., a polyester resin of 10,000 to 30,000 Mw) is used to ensure moldability. As its molecular weight increases, the polyester resin increases the elongation of the coating film, which may increase the moldability of the PCM steel sheet. However, as the molecular weight of 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. As the molecular weight of polyester increases, the hardness (scratch resistance) of the PCM steel sheet may decrease. For these reasons, the PCM steel sheet may have inferior appearance quality compared to the VCM steel sheet. Accordingly, there is a need to develop PCM steel sheets that have the same appearance quality and hardness as the VCM steel sheet.

[0103] The composition of the PCM steel sheet 200 to secure the appearance quality and hardness of the PCM steel sheet is described below.

[0104] Table 3 is a table illustrating the results of gloss, distinctness of reflective image (DOI), moldability test, and surface hardness of the clear coating layer 260 according to the molecular weight of the polyester resin of 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 sheet was bent to bring the portions into contact with each other. Here, as the gloss, the amount of reflected light when light is incident on the surface at an angle of 20 degrees was measured using a gloss meter.TABLE 3molecular weight (Mw)5000 to 80008000 to 1200020000 to 2500020° gloss (GU)91.282.180.3distinctness of47.141.739.4reflective image(DOI)bending test (0 T)no crackno crackno crackcupping testcrackno crackno crackimpact testwhiteningno whiteningno whiteningpress testwhiteningno whiteningno whiteningsurface hardnessFHB2B to B

[0105] Referring to Table 3, when the molecular weight of the polyester resin of the clear coating layer 260 is 5000 to 8000 Mw, it may be identified that the clear coating layer 260 has a gloss of 91.2 gloss units (GU) and a distinctness of image (DOI) of 47.1. Further, it may be identified that cracks and whitening occur in the moldability test of the clear coating layer 260 except for the bending test. Further, it may be identified that the hardness of the clear coating layer 260 is F.

[0106] When the molecular weight of the polyester resin of the clear coating layer 260 is 8000 to 12000 Mw, it may be identified that the clear coating layer 260 has a gloss of 82.1 GU and a DOI of 41.7. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0107] When the molecular weight of the polyester resin of the clear coating layer 260 is 20000 to 25000 Mw, it may be identified that the clear coating layer 260 has a gloss of 80.3 GU and a DOI of 39.4. Further, it may be identified that cracks and whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is 2B to B.

[0108] Referring to FIG. 4 based on the data values in Table 3, it may be identified again that as the molecular weight of the polyester resin included in the clear coating layer 260 increases, the moldability is good, but the gloss, DOI, and surface hardness decrease.

[0109] As a result, the clear coating layer 260 may 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.

[0110] According to an embodiment, the clear coating layer 260 may include a polyester resin and an acrylic resin. The acrylic resin is an amorphous resin and has low light scattering and high transparency due to its structural and optical properties. When an acrylic resin is included in the clear coating layer 260, the gloss of the clear coating layer 260 may be enhanced by the physical properties of the acrylic resin.

[0111] Table 4 is a table illustrating the gloss, moldability, and surface hardness according to the ratio of polyester resin and acrylic resin in the clear coating layer 260.TABLE 4polyester:acrylic100:095:590:1085:1580:20gloss82.185.586.086.886.5bending testno crackno crackno crackno crackno crack(0 T)impact testnononowhiteningwhiteningwhiteningwhiteningwhiteningsurfaceBHBHBHBFhardness

[0112] 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 may be identified that the gloss of the clear coating layer 260 has a value of 82.1 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is B.

[0113] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 95 to 5, it may be identified that the gloss of the clear coating layer 260 has a value of 85.5 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0114] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 90 to 10, it may be identified that the gloss of the clear coating layer 260 has a value of 86.0 GU. Further, it may be identified that cracks and whitening do not occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0115] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 85 to 15, it may be identified that the gloss of the clear coating layer 260 has a value of 86.8 GU. Further, it may be identified that cracks do not occur in the moldability test of the clear coating layer 260. But it may be identified whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is HB.

[0116] When the ratio of polyester resin and acrylic resin included in the clear coating layer 260 is 80 to 20, it may be identified that the gloss of the clear coating layer 260 has a value of 86.5 GU. Further, it may be identified that cracks do not occur in the moldability test of the clear coating layer 260. But it may be identified that whitening occur in the moldability test of the clear coating layer 260. Further, it may be identified that the hardness of the clear coating layer 260 is F.

[0117] It may be identified that as the content proportion of acrylic resin relative to polyester resin increases, the gloss increases, but the gloss converges when the proportion of acrylic resin is 15% or more. Further, it may be identified that a hardness of HB or higher is secured when the proportion of acrylic resin is 5% or higher. However, it may be identified that the moldability is not secured as whitening occur when the proportion of acrylic resin exceeds 15%.

[0118] As a result, the clear coating layer 260 may secure a gloss of about 85.5 GU to 86.0 GU, moldability, and a hardness of HB or higher when the proportion of the acrylic resin relative to the polyester resin is 5 to 10%.

[0119] FIG. 5 is a graph illustrating the distinctness of image (DOI) and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure.

[0120] FIG. 6 is a graph illustrating the distinctness of image (DOI) and luminance according to the particle size, per content, of an aluminum paste, which is a metallic pigment of a base coating layer, according to an embodiment of the disclosure.

[0121] According to an embodiment, the base coating layer 240 of the PCM steel sheet 200 may include a metallic pigment. In an embodiment, the metallic pigment of the base coating layer 240 may include aluminum paste. The aluminum paste may be used to enhance the gloss and / or luminance of the PCM steel sheet 200 by utilizing the mirror effect. However, in the case of PCM steel sheets, as the particle size of the pigment increases, the surface roughness increases, which may reduce the gloss and / or distinctness of image (DOI).

[0122] Referring to FIGS. 5 and 6, in the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 61.8 and a luminance of 9.12 candela per square meter (cd / m2) when the particle size of the aluminum paste is 12 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 53.6 and a luminance of 9.42 cd / m2 when the particle size of the aluminum paste is 19 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 50.5 and a luminance of 9.34 cd / m2 when the particle size of the aluminum paste is 23 μm. In the case of 4 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 42 and a luminance of 11.2 cd / m2 when the particle size of the aluminum paste is 32 μm.

[0123] In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 56.5 and a luminance of 9.31 cd / m2 when the particle size of the aluminum paste is 12 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 46.7 and a luminance of 10.9 cd / m2 when the particle size of the aluminum paste is 19 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 34.6 and a luminance of 10.46 cd / m2 when the particle size of the aluminum paste is 23 μm. In the case of 8 wt % of the aluminum paste relative to the total weight of the base coating layer 240, the PCM steel sheet 200 may have a DOI of 24.4 and a luminance of 12.46 cd / m2 when the particle size of the aluminum paste is 32 μm.

[0124] As a result, as the particle size of the aluminum paste decreases, the density of particles per unit area increases, which may increase the DOI. As the size of the aluminum paste increases, the interference between particles decreases, which may decrease diffuse reflection, leading to higher luminance. However, it may be identified that the difference in luminance is insignificant, as compared with the DOI, according to changes in particle size.

[0125] FIG. 7 is a graph illustrating the gloss, the distinctness of image (DOI), and luminance according to the particle size, per particle shape, of an aluminum paste according to an embodiment of the disclosure.

[0126] According to an embodiment, in the base coating layer 240, the aluminum paste, which is a metallic pigment, may have various forms. For example, the aluminum paste may have the form of cornflakes (or flakes) or silver dollars. The aluminum paste in the form of cornflakes may be referred to as aluminum flakes.

[0127] Referring to FIG. 7, in the case of aluminum paste in the form of cornflakes, when the content of aluminum paste is 12 wt % and the particle size is 10 to 12 μm, the gloss may have a value of 94.3 GU, the distinctness of image (DOI) may have a value of 57.7, and the luminance (F.I) may have a value of 10.11 cd / m2. When the content of aluminum paste is 6 wt % and the particle size is 19 to 21 μm, the gloss may have a value of 84.9 GU, the distinctness of image (DOI) may have a value of 44.5, and the luminance (F.I) may have a value of 12.9 cd / m2. When the content of aluminum paste is 2.5 to 3 wt % and the particle size is 30 to 32 μm, the gloss may have a value of 74.8 GU, the distinctness of image (DOI) may have a value of 33.4, and the luminance (F.I) may have a value of 11.23 cd / m2.

[0128] In the case of aluminum paste in the form of silver dollar, when the content of aluminum paste is 12 wt % and the particle size is 10 to 12 μm, the gloss may have a value of 94.5 GU, the distinctness of image (DOI) may have a value of 57.3, and the luminance (F.I) may have a value of 11.23 cd / m2. When the content of aluminum paste is 6 wt % and the particle size is 19 to 21 μm, the gloss may have a value of 84.6 GU, the distinctness of image (DOI) may have a value of 43.7, and the luminance (F.I) may have a value of 11.64 cd / m2. When the content of aluminum paste is 2.5 to 3 wt % and the particle size is 30 to 32 μm, the gloss may have a value of 64.3 GU, the distinctness of image (DOI) may have a value of 16.4, and the luminance (F.I) may have a value of 11.17 cd / m2.

[0129] In the case of aluminum paste in the form of silver dollar, as the shape of the particles is rounded and regular, the circumferential length is shorter in relation to the surface area compared to aluminum paste in the form of irregular cornflake structure, which may reduce light scattering.

[0130] As a result, the aluminum paste in the form of silver dollar may secure high luminance (e.g., a luminance of 9 cd / m2 or more) while ensuring gloss and DOI even when it has a small particle size of 10 to 12 μm.

[0131] A PCM steel sheet 200 for a home appliance according to an embodiment of the disclosure may comprise a steel sheet 210, a chemical conversion coating layer 220 disposed on the steel sheet 210, a primer 230 disposed on the chemical conversion coating 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. An average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0132] According to an embodiment, the clear coating layer 260 may further include an acrylic resin.

[0133] According to an embodiment, a content proportion of the acrylic resin relative to the polyester resin may be 5% to 10%.

[0134] According to an embodiment, a pigment of the base coating layer 240 may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0135] According to an embodiment, the aluminum paste may have particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

[0136] According to an embodiment, the particles may have a particle size of 10 μm to 20 μm.

[0137] According to an embodiment, the clear coating layer may have a surface hardness of HB or more.

[0138] According to an embodiment, the clear coating layer may have a 20-degree gloss of 80GU or more.

[0139] According to an embodiment, the clear coating layer may have a distinctness of image of 40 or more.

[0140] According to an embodiment, the clear coating layer may have a luminance of 9 cd / m2 or more.

[0141] A washing machine 1 according to an embodiment of the disclosure may comprise a casing 10 including a plurality of panels 11, a tub 20 disposed in the casing 10, and a drum 30 in the tub 20 and configured to rotate in the tub 20. The plurality of panels 11 may include a PCM steel sheet 200. The PCM steel sheet 200 may comprise a steel sheet 210, a chemical conversion coating layer 220 disposed on the steel sheet 210, a primer 230 disposed on the chemical conversion coating 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. An average molecular weight (Mw) of the polyester resin may be 8000 to 12000.

[0142] According to an embodiment, the clear coating layer 260 may further include an acrylic resin.

[0143] According to an embodiment, a content proportion of the acrylic resin relative to the polyester resin may be 5% to 10%.

[0144] According to an embodiment, a pigment of the base coating layer 240 may include a metallic pigment. The metallic pigment may include an aluminum paste.

[0145] According to an embodiment, the aluminum paste may have particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

[0146] According to an embodiment, the particles may have a particle size of 10 μm to 20 μm.

[0147] According to an embodiment, the clear coating layer may have a surface hardness of HB or more.

[0148] According to an embodiment, the clear coating layer may have a 20-degree gloss of 80GU or more.

[0149] According to an embodiment, the clear coating layer may have a distinctness of image of 40 or more.

[0150] According to an embodiment, the clear coating layer may have a luminance of 9 cd / m2 or more.

[0151] In the disclosure, the above-described description has been made mainly of specific embodiments, but the disclosure is not limited to such specific embodiments, but should rather be appreciated as covering all various modifications, equivalents, and / or substitutes of various embodiments.

Examples

Embodiment Construction

[0017]It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment.

[0018]With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements.

[0019]It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise.

[0020]As used herein, each of such phrases as “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 all possible combinations of the items enumerated together in a corresponding one of the phrases.

[0021]The term “and / or” may denote a combination(s) of a plurality of related components as listed or any...

Claims

1. A pre-coated metal (PCM) steel sheet for a home appliance, comprising:a steel sheet;a chemical conversion coating layer on the steel sheet;a primer on the chemical conversion coating layer;a base coating layer on the primer, the base coating layer including a pigment;a print layer on the base coating layer; anda clear coating layer on the print layer, the clear coating layer including a polyester resin,wherein an average molecular weight (Mw) of the polyester resin is 8000 to 12000.

2. The PCM steel sheet of claim 1, wherein the clear coating layer further includes an acrylic resin.

3. The PCM steel sheet of claim 2, wherein a content proportion of the acrylic resin relative to the polyester resin is 5% to 10%.

4. The PCM steel sheet of claim 1, whereinthe pigment of the base coating layer includes a metallic pigment, andthe metallic pigment includes an aluminum paste.

5. The PCM steel sheet of claim 4, wherein the aluminum paste includes particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

6. The PCM steel sheet of claim 5, wherein the particles have a particle size of 10 μm to 20 μm.

7. The PCM steel sheet of claim 1, wherein the clear coating layer has a surface hardness of HB or more.

8. The PCM steel sheet of claim 1, wherein the clear coating layer has a 20-degree gloss of 80 GU or more.

9. The PCM steel sheet of claim 1, wherein the clear coating layer has a distinctness of image (DOI) of 40 or more.

10. The PCM steel sheet of claim 1, wherein the clear coating layer has a luminance of 9 cd / m2 or more.

11. A washing machine, comprising:a casing including a plurality of panels;a tub in the casing; anda drum in the tub, the drum configured to rotate in the tub,wherein the plurality of panels include a pre-coated metal (PCM) steel sheet, andthe PCM steel sheet includes:a steel sheet,a chemical conversion coating layer on the steel sheet,a primer on the chemical conversion coating layer,a base coating layer on the primer, the base coating layer including a pigment,a print layer on the base coating layer, anda clear coating layer on the print layer, the clear coating layer including a polyester resin, andan average molecular weight (Mw) of the polyester resin is 8000 to 12000.

12. The washing machine of claim 11, wherein the clear coating layer further includes an acrylic resin.

13. The washing machine of claim 12, wherein a content proportion of the acrylic resin relative to the polyester resin is 5% to 10%.

14. The washing machine of claim 11, whereinthe pigment of the base coating layer includes a metallic pigment, andthe metallic pigment includes an aluminum paste.

15. The washing machine of claim 14, wherein the aluminum paste includes particles that have a shape that is rounded and regular corresponding to a shape of a silver dollar.

16. The washing machine of claim 15, wherein the particles have a particle size of 10 μm to 20 μm.

17. The washing machine of claim 11, wherein the clear coating layer has a surface hardness of HB or more.

18. The washing machine of claim 11, wherein the clear coating layer has a 20-degree gloss of 80 GU or more.

19. The washing machine of claim 11, wherein the clear coating layer has a distinctness of image (DOI) of 40 or more.

20. The washing machine of claim 11, wherein the clear coating layer has a luminance of 9 cd / m2 or more.

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