Molded body having thermal controlling

Abstract

The present invention relates to a molded body with thermal control capability, comprising: a core layer comprising a phase change material; and surface layers laminated on both surfaces of the core layer and containing a first polymer resin. The present invention also relates to a method for manufacturing a molded body having thermal control ability, comprising: a core layer composition forming step for forming a core layer composition containing a phase change material; a surface layer composition forming step for forming a surface layer composition containing a first polymer resin; and a heterogeneity injection step for heterogeneously injecting the composition for the core layer and the composition for the surface layer to form a molded body. According to the molded body having the heat control capability, the phenomenon that the temperature of the molded body is easy to rise can be controlled through the latent heat of the phase change material without additionally performing a microencapsulation process, and the heat absorption and reflection performance of the molded body can be controlled, so that the indoor environment temperature can be effectively controlled.

Description

Molded bodies with thermal control capabilities and their manufacturing methods Technical Field

[0001] This invention relates to a molded article with thermal control capabilities and a method for manufacturing the same. More specifically, it relates to a molded article with thermal control capabilities and a method for manufacturing the same, which has a sandwich structure consisting of a core layer and a surface layer containing a phase change material (PCM), thereby controlling the tendency of the molded article to rise in temperature through the latent heat of the phase change material without the need for an additional microencapsulation process, and controlling the heat absorption and reflection properties of the molded article, and can also effectively control the indoor ambient temperature. Background Technology

[0002] With the development of the automotive industry, plastics have replaced metals in many materials, and are now widely used in various automotive applications, including car bodies, exteriors, interiors, trim, and engine rotation. Plastics offer advantages such as ease of molding and processing, light weight, and economy. In particular, the use of plastics in the automotive industry is especially relevant to reducing fuel consumption through lightweighting.

[0003] In the automotive industry, efforts have long focused on lightweighting vehicle bodies to achieve reduced environmental impact or improved operational performance through enhanced fuel efficiency. Recently, with the increasing severity of air pollution, countries worldwide are gradually tightening fuel efficiency restrictions to reduce exhaust emissions; therefore, improving fuel efficiency through lightweighting is a crucial issue.

[0004] To improve fuel efficiency, powertrains are shifting from gasoline engines to hybrid and EV models. However, the heavy weight of components specifically designed for environmentally friendly vehicles, such as batteries, contributes to the overall weight of these vehicles compared to existing internal combustion engine vehicles. Increased weight leads to decreased energy efficiency, making lightweight vehicle technology a crucial issue in the future automotive market. Furthermore, consumer demands for safety and convenience also contribute to increased vehicle weight. Therefore, the automotive industry urgently needs to reduce the weight of existing components, and product performance differences based on lightweight technologies are expected to become a key factor determining competitiveness in the future.

[0005] Based on the total weight of a car, plastics currently account for approximately 20% of its composition, and this figure is expected to increase further with the development of engineering plastics, plastic alloys, and composite materials. As a new material in the automotive industry, plastics have unlimited development prospects and possibilities, and will make significant contributions to reducing vehicle weight, increasing fuel efficiency, improving safety, enhancing ride comfort, reducing emissions, lowering prices, increasing performance, improving productivity, and refining styling.

[0006] However, plastic materials have high emissivity, so the temperature of interior materials made of plastic can easily rise when the vehicle interior is heated. In particular, the interior temperature of a closed vehicle can rise to 2 to 3 times the outside temperature during the day, which may cause safety issues such as the risk of explosion of flammable materials inside the vehicle or skin burns to children or toddlers, and may also cause problems such as increased energy consumption to maintain a suitable temperature inside the vehicle.

[0007] In response, various technologies are being developed to control the temperature of automotive interior materials made of plastic.

[0008] In addition, phase change materials (PCMs) are substances that can accumulate or release a large amount of latent heat without causing temperature changes during the phase change process from solid to liquid, from liquid to gas, or vice versa at phase change temperatures. Many studies and developments are underway regarding their application as thermal control materials.

[0009] However, when this phase change material is applied as is to automotive interior materials, when it is mixed into injection resin and undergoes a phase change from solid to liquid above its melting point, the phase change material is exposed on the surface of the injection resin, thus making it difficult to use as an automotive interior material.

[0010] To prevent this problem, the phase change material must be encapsulated within microcapsules through a microencapsulation process. However, this microencapsulation process is costly, increasing expenses and making it difficult to use as a material in automotive interiors in practice.

[0011] Patent Document 1 relates to automotive seat and interior materials using phase change materials, and a method for manufacturing the same. It discloses mixing phase change materials, waterborne polyurethane resin, fragrance, antibacterial agent and deodorant to form a coating liquid or impregnation liquid, and then coating or impregnating the manufactured coating liquid or impregnation liquid onto a fabric for processing and use as an automotive seat or interior material.

[0012] Patent document 2 relates to composite particles of phase change material and conductive filler for thermal control materials and its manufacturing method, and discloses a method for manufacturing nanocomposite particles by coating with phase change material as the core and conductive filler as the shell.

[0013] However, Patent Document 1 still has the problem of being exposed on the surface and difficult to handle when a phase transition to the liquid phase occurs above the melting point. In addition, Patent Document 2 is a technology applied to battery heat dissipation systems, etc. When mixed into plastic injection molding resin, there may be problems with compatibility and dispersibility with the resin, and there are concerns about reduced moldability and overall product properties.

[0014] In response, the automotive industry still needs to develop a technology that can simultaneously meet the requirements of lightweighting and ensuring physical properties, while also overcoming the problems caused by the low particle size of traditional powder-type thermally expandable microcapsules.

[0015] Prior art is technical information that the inventor possesses in order to derive the present invention or obtains in the process of deriving the present invention. It cannot be said that it necessarily constitutes publicly known technology that was disclosed to the general public before the application of this invention.

[0016] Prior art literature: Patent literature Patent literature 1: Korean Patent Publication No. 10-2015-0081953 (published on July 15, 2015) Patent literature 2: Korean Patent Publication No. 10-2013-0067128 (published on June 21, 2013) Summary of the Invention (Technical Problem to be Solved) In terms of solving the aforementioned problems, the object of the present invention is to provide a molded body with thermal control capability, which has a sandwich structure consisting of a core layer and a surface layer containing a phase change material, thereby controlling the phenomenon of easy temperature rise of the molded body through the latent heat of the phase change material, and controlling the heat absorption and reflection properties of the molded body, thereby effectively controlling the indoor ambient temperature.

[0017] Furthermore, the present invention aims to provide a method for manufacturing a molded body with thermal control capabilities, which eliminates the need for additional microencapsulation processes that complicate the process and increase costs, and enables effective temperature control through heterogeneous injection molding.

[0018] The problems to be solved by the present invention are not limited to those mentioned above. For those skilled in the art, other issues not mentioned can be clearly understood from the following description.

[0019] (Solution to the problem) A molded body with thermal control capability according to an embodiment of the present invention includes: a core layer comprising a phase change material; and a surface layer stacked on both sides of the core layer and comprising a first polymer resin.

[0020] At this point, the phase change material may contain paraffinic hydrocarbons.

[0021] Specifically, the phase change material may comprise N-eicosane, N-octadecane, N-heptadecane, or a combination thereof.

[0022] Furthermore, based on the total weight of the core layer, the phase change material may comprise 15 to 25% by weight.

[0023] At this time, the core layer may also include a second polymer resin, a first filler material, and a second filler material.

[0024] At this time, the second polymer resin may contain polypropylene (PP), acrylonitrile butadiene styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0025] In addition, the first filler material may contain talc, calcium carbonate (CaCO3), or a combination thereof.

[0026] In addition, the second filler material may contain silica, zeolite, or a combination thereof.

[0027] At this time, based on the total weight of the core layer, the core layer may contain 55-70% by weight of the second polymer resin, 10-15% by weight of the first filler material, and 4-5% by weight of the second filler material.

[0028] At this time, the core layer may also contain additives selected from antioxidants, pigments, lubricants, nucleating agents, UV stabilizers, or combinations thereof.

[0029] Based on the total weight of the core layer, the additive may contain a range of more than 0% by weight and less than 1% by weight.

[0030] In addition, the first polymeric resin may comprise polypropylene (PP), acrylonitrile butadiene styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0031] At this time, the first polymer resin and the second polymer resin may contain the same substances as each other.

[0032] Furthermore, based on the total weight of the surface layer, the first polymeric resin may contain 87 to 97% by weight.

[0033] At this time, the surface layer may also include heat-reflective fillers and heat-absorbing fillers.

[0034] The heat-reflective filler comprises alumina (Al2O3), spherical aluminum, titanium oxide (TiO2), zinc oxide (ZnO), or a combination thereof, and the heat-absorbing filler comprises carbon-based fillers.

[0035] Specifically, the heat-absorbing filler may comprise carbon nanotubes (CNTs), graphite, graphene, carbon black, or a combination thereof.

[0036] At this point, based on the total weight of the surface layer, the surface layer may contain 1 to 10% by weight of the heat-reflective filler and 1 to 5% by weight of the heat-absorbing filler.

[0037] A method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention includes: a core layer composition forming step of forming a core layer composition comprising a phase change material; a surface layer composition forming step of forming a surface layer composition comprising a first polymer resin; and a heterogeneous injection step of heterogeneous injection of the core layer composition and the surface layer composition to form a molded article.

[0038] Here, the core layer composition forming step may include the step of mixing the phase change material, the second polymer resin, the first filler material and the second filler material.

[0039] Furthermore, the core layer composition forming step may include: a first step of adding the second polymer resin in solid form; a second step of adding the first filler material and the second filler material in solid form after the first step; and a step of adding the phase change material in liquid form after the second step.

[0040] Furthermore, in the core layer composition forming step, the second polymer resin, the first filler material, and the second filler material can be directly fed into the hopper of the extrusion device in solid form, and the phase change material can be fed in liquid form through a liquid feeder.

[0041] At this time, the core layer composition forming step can be achieved by compounding and extrusion at a temperature in the range of 120 to 180°C.

[0042] In addition, the core layer composition forming step may include: mixing the phase change material in a range of 15 to 25% by weight, based on the total weight of the core layer composition.

[0043] At this point, the phase change material may contain paraffinic hydrocarbons.

[0044] Specifically, the phase change material may comprise N-eicosane, N-octadecane, N-heptadecane, or a combination thereof.

[0045] At this time, the second polymer resin may contain polypropylene (PP), acrylonitrile butadiene styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0046] In addition, the first filler material may contain talc, calcium carbonate (CaCO3), or a combination thereof.

[0047] In addition, the second filler material may contain silica, zeolite, or a combination thereof.

[0048] At this time, the core layer composition forming step may include: mixing 55-70% by weight of the second polymer resin, 10-15% by weight of the first filler material and 4-5% by weight of the second filler material based on the total weight of the core layer composition.

[0049] In addition, the core layer composition forming step may further include the step of mixing an additive selected from antioxidants, pigments, lubricants, nucleating agents, UV stabilizers, or combinations thereof.

[0050] At this time, the core layer composition forming step may include: mixing the additives in a range of more than 0% by weight and less than 1% by weight, based on the total weight of the core layer composition.

[0051] In addition, the first polymeric resin may comprise polypropylene (PP), acrylonitrile butadiene styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0052] At this time, the first polymer resin and the second polymer resin may contain the same substances as each other.

[0053] In addition, the step of forming the surface composition may include: mixing the first polymeric resin in a range of 87 to 97% by weight, based on the total weight of the surface composition.

[0054] In addition, the step of forming the surface layer composition may further include the step of mixing heat-reflective filler and heat-absorbing filler.

[0055] At this time, the heat-reflective filler comprises alumina (Al2O3), spherical aluminum, titanium oxide (TiO2), zinc oxide (ZnO) or a combination thereof, and the heat-absorbing filler comprises carbon-based fillers.

[0056] Specifically, the heat-absorbing filler may comprise carbon nanotubes (CNTs), graphite, graphene, carbon black, or a combination thereof.

[0057] Furthermore, the step of forming the surface layer composition may include: mixing 1 to 10% by weight of the heat-reflective filler and 1 to 5% by weight of the heat-absorbing filler based on the total weight of the surface layer composition.

[0058] Additionally, the heterologous injection step may include: a first injection step of injecting the surface layer composition and a second injection step of injecting the core layer composition.

[0059] At this time, the first injection step can be performed at a temperature range of 200 to 240°C, and the second injection step can be performed at a temperature range of 160 to 180°C.

[0060] (Effects of the Invention) As described above, the molded body with thermal control capability according to the embodiments of the present invention, by having a sandwich structure consisting of a core layer and a surface layer containing a phase change material, can achieve the temperature control effect caused by the heat storage of the phase change material contained in the core layer and the desired heat transfer efficiency caused by the heat reflective filler and the heat absorbent filler contained in the surface layer.

[0061] Furthermore, according to embodiments of the present invention, the molded body with thermal control capability controls the phenomenon of easy temperature rise of the molded body by using the latent heat of the phase change material, and thus can control the indoor ambient temperature without using electricity.

[0062] Furthermore, the molded body with thermal control capability according to embodiments of the present invention, when used as an automotive interior material, can control not only the temperature rise inside the vehicle caused by radiant heat, but also the temperature rise inside the vehicle caused by convective heat by controlling the heat absorption and reflection properties of the interior material. This can improve the efficiency of the automotive air conditioning and heater, and increase the driving range by improving the thermal efficiency of the electric vehicle.

[0063] Furthermore, according to the method for manufacturing a molded body with thermal control capability according to embodiments of the present invention, a molded body with thermal control capability that can effectively control temperature can be easily manufactured by heterogeneous injection molding without performing an additional microencapsulation process that complicates the process and increases costs.

[0064] The effects of the present invention are not limited to those mentioned above. Other effects not mentioned can be clearly understood by those skilled in the art through the following description. Attached Figure Description

[0065] Figure 1 is a schematic diagram showing a molded article with thermal control capability according to an embodiment of the present invention.

[0066] Figure 2 is a flowchart illustrating a method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention.

[0067] Figure 3 is a schematic diagram of an extrusion apparatus for forming a core layer composition in a method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention.

[0068] Figure 4 is a schematic diagram illustrating the co-injection process in a method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention.

[0069] Figure 5 is a graph showing the temperature change of the molded body relative to changes in the ambient temperature.

[0070] (Explanation of reference numerals in the attached diagram) 10: Molded body with thermal control capability; 11: Surface layer; 12: Core layer; 20: Extrusion device; 21: Hopper; 22: Liquid feeder; 23: Die head; 30: Mold; 31: Cavity In this invention, for the purpose of differentiation and clarity from the prior art, and to facilitate understanding of the technology, the accompanying drawings may be presented in an exaggerated form. Furthermore, the terms used below are defined in consideration of their function in this invention and may vary depending on the intention or convention of the user; therefore, the definitions of these terms should be based on the overall technical content of this specification. Additionally, the embodiments are merely illustrative examples of the constituent elements set forth in the claims of this invention, and are not intended to limit the scope of the invention; the scope of the invention should be interpreted based on the overall technical concept of this specification.

[0071] Throughout the specification, when one component is described as "containing" another component, unless there is a particularly contrary statement, it does not exclude other components, but rather implies that other components may be further included.

[0072] Furthermore, when a component is described as "connected," "continued," or "combined" with another component, this not only means "directly connected," "directly continued," or "directly combined," but also may include "connected in a manner that involves other components," "continued in a manner that involves other components," or "combined in a manner that involves other components." Conversely, when a component is described as "directly connected," "directly continued," or "directly combined" with another component, it should be understood that there are no other components in between.

[0073] Furthermore, when directional terms such as “front,” “back,” “up,” “down,” “left,” “right,” “one end,” “the other end,” and “both ends” are used, these are used exemplarily relative to the orientation of the disclosed figures and should not be interpreted restrictively. When terms such as “first” and “second” are used, these are terms used to distinguish the constituent parts and should not be interpreted restrictively.

[0074] To more clearly illustrate the features of the embodiments of the present invention, detailed descriptions of matters widely known to those skilled in the art to which the following embodiments pertain will be omitted. Furthermore, detailed descriptions of portions of the drawings unrelated to the illustrative embodiments will also be omitted.

[0075] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0076] Figure 1 is a schematic diagram showing a molded article with thermal control capability according to an embodiment of the present invention; Figure 2 is a flowchart showing a method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention; Figure 3 is a schematic diagram showing an extrusion apparatus used in the core layer composition forming step in the method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention; Figure 4 is a schematic diagram illustrating the co-injection process in the method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention; and Figure 5 is a graph showing the temperature change of the molded article relative to changes in ambient temperature.

[0077] Referring to FIG1, the molded body 10 with thermal control capability according to an embodiment of the present invention includes a core layer 12 and a surface layer 11.

[0078] The core layer 12 enables the molded body 10 to exert its thermal control capabilities.

[0079] Therefore, the core layer 12 contains a phase change material.

[0080] The phase change material is a substance that can accumulate or release a large amount of latent heat without causing a temperature change during the phase change process from solid to liquid, from liquid to gas, or in the opposite direction at the phase change temperature.

[0081] In this embodiment, by including the phase change material in the core layer 12, when the space of the molded body 10 is heated, such as inside a vehicle, the temperature of the molded body 10 can be controlled to prevent it from rising too easily by storing heat.

[0082] Furthermore, in this embodiment, the phase change material can be contained in the core layer 12 in the form of a raw material without encapsulation.

[0083] In one embodiment, the phase change material may comprise paraffinic hydrocarbons.

[0084] In one embodiment, the phase change material may comprise N-eicosane, N-octadecane, N-heptadecane, or a combination thereof, preferably N-eicosane.

[0085] The phase change materials each have different melting points, so the melting point can be taken into account when making an appropriate selection.

[0086] For example, N-eicosane has a melting point of 38°C, N-octadecane has a melting point of 28°C, and N-heptadecane has a melting point of 22°C. In one embodiment, N-eicosane, which has a melting point similar to body temperature, can be selected as the phase change material.

[0087] Based on the total weight of the core layer 12, the phase change material can be in the range of 15-25% by weight. When the content of the phase change material is less than the range, the thermal storage capacity will be insufficient, thus failing to exert the normal thermal control capability. When it exceeds the range, the dispersibility will be reduced during the mixing and extrusion process in the formation of the core layer, which may cause backflow or bridging in the hopper of the extrusion device.

[0088] The core layer 12 may also include a second polymer resin, a first filler material, and a second filler material.

[0089] The second polymer resin may be a base resin that serves as the substrate of the core layer 12.

[0090] The second polymer resin can be appropriately selected according to the physical properties required for the application of the molded body 10 with thermal control capability, such as the physical properties required for automotive interior parts.

[0091] In one embodiment, the second polymeric resin may comprise polypropylene (PP), acrylonitrile butadiene-styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0092] Based on the total weight of the core layer 12, the second polymer resin may contain 55-70% by weight. When the content of the second polymer resin is less than the range, it may be difficult to meet the required physical properties according to the application. When it exceeds the range, the thermal control capability cannot be properly exerted due to insufficient content of the phase change material, or the content of the first filler and the second filler is insufficient, making it difficult to impregnate the phase change material, which may cause problems in the formation of the composition.

[0093] The first filler material can enhance the physical properties of the core layer 12 and effectively impregnate the phase change material.

[0094] In one embodiment, the first filler material may comprise talc, calcium carbonate (CaCO3), or a combination thereof.

[0095] Based on the total weight of the core layer 12, the first filler material may contain 10-15% by weight. When the content of the first filler material is less than the range, it is difficult to achieve the normal physical property enhancement and phase change material impregnation effect. When it exceeds the range, it may cause problems with dispersibility and may lead to a decrease in physical properties.

[0096] The second filler material can effectively impregnate the phase change material.

[0097] In one embodiment, the second filler material may comprise silica, zeolite, or a combination thereof.

[0098] Based on the total weight of the core layer 12, the second filler material may contain 4-5% by weight. When the content of the second filler material is less than the range, it is difficult to achieve the proper impregnation effect of the phase change material. When it exceeds the range, it may cause problems with dispersibility and may lead to a decrease in physical properties.

[0099] To improve physical properties and prevent thermal decomposition of the phase change material, the core layer 12 may also contain additives.

[0100] The additive may be selected from antioxidants, pigments, lubricants, nucleating agents, UV stabilizers, or combinations thereof.

[0101] The antioxidant can prevent the thermal decomposition of the phase change material, and may include, for example, butylated hydroxytoluene (BHT).

[0102] Based on the total weight of the core layer 12, the additive may contain a range of more than 0% by weight and less than 1% by weight.

[0103] The surface layer 11 prevents the phase change material contained in the core layer 12 from leaking out as it changes into a liquid at its melting point, and also compensates for the decrease in physical properties caused by the phase change material. Furthermore, the surface layer 11 has heat reflection and heat absorption functions, thereby maximizing the desired heat transfer efficiency.

[0104] The surface layer 11 is stacked on both sides of the core layer 12 and may contain a first polymer resin.

[0105] In this embodiment, even if the phase change material contained in the core layer 12 is not encapsulated and is used in its raw material form, the problem of leakage of the unencapsulated phase change material can be solved by stacking the surface layer 11 on both sides of the core layer 12.

[0106] The first polymer resin may be a base resin that serves as the substrate of the surface layer 11.

[0107] The first polymer resin can be appropriately selected according to the physical properties required for the application of the molded body 10 with thermal control capability, such as the physical properties required for automotive interior parts.

[0108] The first polymeric resin may comprise polypropylene (PP), acrylonitrile butadiene styrene copolymer (ABS), polyamide 6 (PA6), polycarbonate (PC), or a combination thereof.

[0109] Based on the total weight of the surface layer 11, the first polymeric resin may contain 87-97% by weight. When the content of the first polymeric resin is less than the range, it may be difficult to meet the physical properties required for the application, and the property supplementation effect may be insufficient. When it exceeds the range, it is difficult for the surface layer 11 to perform its heat reflection and heat absorption functions normally.

[0110] In one embodiment, the first polymer resin and the second polymer resin may contain the same substances as each other.

[0111] The surface layer 11 may also include heat-reflective fillers and heat-absorbing fillers.

[0112] The heat-reflective filler and the heat-absorbing filler can enable the surface layer 11 to perform heat reflection and heat absorption functions, thereby maximizing the desired heat transfer efficiency.

[0113] The heat-reflective filler may contain alumina (Al2O3), spherical aluminum, titanium oxide (TiO2), zinc oxide (ZnO), or a combination thereof.

[0114] Based on the total weight of the surface layer 11, the heat-reflective filler can contain 1 to 10% by weight. When the content of the heat-reflective filler is less than this range, the heat reflection effect will be insufficient, thus failing to achieve the desired heat transfer efficiency. When it exceeds this range, there are concerns about dispersibility and reduced physical properties.

[0115] The heat-absorbing filler may contain carbon-based fillers, including carbon nanotubes (CNTs), graphite, graphene, carbon black, or combinations thereof.

[0116] Based on the total weight of the surface layer, the heat-absorbing filler can comprise 1 to 5% by weight. When the content of the heat-absorbing filler is less than this range, the heat absorption effect will be insufficient, thus failing to achieve the desired heat transfer efficiency. When it exceeds this range, there are concerns about dispersibility and reduced physical properties.

[0117] According to an embodiment of the present invention, the molded body 10 with thermal control capability, by having a sandwich structure consisting of a core layer 12 containing a phase change material and a surface layer 11, can achieve a temperature control effect caused by heat storage due to the phase change material contained in the core layer 12 and a desired heat transfer efficiency caused by the heat-reflective filler and the heat-absorbing filler contained in the surface layer 11. Furthermore, even without encapsulating the phase change material, the latent heat of the phase change material can be used to control the tendency for the temperature of the molded body to rise easily, thereby enabling the control of the interior ambient temperature without the use of electricity. Further, according to an embodiment of the present invention, when the molded body 10 with thermal control capability is used as an automotive interior material, by controlling the heat absorption and reflection properties of the interior material, it is possible not only to control the rise in interior temperature caused by radiant heat but also to control the rise in interior temperature caused by convective heat, thereby improving the efficiency of automotive air conditioning and heaters, and increasing the driving range by improving the thermal efficiency of electric vehicles.

[0118] Next, referring to FIGS. 1 to 4, a method for manufacturing a molded article with thermal control capability according to an embodiment of the present invention will be described. The method for manufacturing the molded article with thermal control capability shown in FIGS. 2 to 4 is a method for manufacturing the molded article with thermal control capability according to the foregoing embodiment shown in FIG. 1. Therefore, in this embodiment, to avoid repetition, detailed descriptions of the content related to the above embodiment shown in FIG. 1 will be omitted.

[0119] The method for manufacturing a molded article with heat control capability according to embodiments of the present invention may include a core layer composition forming step (S10), a surface layer composition forming step (S20), and a heterogeneous injection step. Furthermore, the method for manufacturing a molded article with heat control capability according to embodiments of the present invention may also include an extraction step (S60).

[0120] The core layer composition forming step (S10) is a step of forming a core layer composition containing a phase change material.

[0121] In the core layer composition forming step (S10), the phase change material can be mixed in the range of 15 to 25% by weight, based on the total weight of the core layer composition.

[0122] The core layer composition forming step (S10) may further include the step of mixing the phase change material, the second polymer resin, the first filler material and the second filler material.

[0123] In the core layer composition forming step (S10), based on the total weight of the core layer composition, 55-70% by weight of the second polymer resin, 10-15% by weight of the first filler material and 4-5% by weight of the second filler material can be mixed.

[0124] The core layer composition forming step (S10) can be achieved by compounding and extrusion at a temperature in the range of 120 to 180°C.

[0125] The temperature of the core layer composition forming step (S10) should be taken into account the thermal decomposition temperature of the phase change material (e.g., 220-240°C in the case of N-eicosane) and mixed at a low temperature to prevent thermal decomposition.

[0126] For example, the core layer composition forming step (S10) can be performed by the extrusion device 20 shown in FIG3, where the temperature on the hopper 21 side can be 120°C and the temperature on the extrusion device die head 23 side can be below 180°C.

[0127] In the core layer composition forming step (S10), if the temperature on the hopper 21 side is too high, or the content of the phase change material is too high, or the phase change material is not properly impregnated by the first filler material and the second filler material, or the melt index (MI) of the core layer 12 is too high, backflow or bridging may occur in the hopper 21.

[0128] The core layer composition forming step (S10) may include: a first step of adding the second polymer resin in solid form; a second step of adding the first filler material and the second filler material in solid form after the first step; and a step of adding the phase change material in liquid form after the second step.

[0129] That is, in the core layer composition forming step (S10), the components can be added in the following order: the second polymer resin, the first filler material, the second filler material, and the phase change material. The second polymer resin, the first filler material, and the second filler material can be added in solid form, and the phase change material can be added in liquid form. By adding the components in the above order in the core layer composition forming step (S10), uniform dispersion of the components and effective impregnation of the phase change material can be achieved.

[0130] In the core layer composition forming step (S10), the second polymer resin, the first filler material, and the second filler material can be directly fed into the hopper 21 of the extrusion device 20 in solid form, while the phase change material can be fed in liquid form through the liquid feeder 22. By separating the solid and liquid components in the core layer composition forming step (S10), uniform dispersion of the components and effective impregnation of the phase change material can be achieved.

[0131] The core layer composition forming step may further include: mixing an additive selected from antioxidants, pigments, lubricants, nucleating agents, UV stabilizers, or combinations thereof.

[0132] The core layer composition forming step may further include: mixing the additives in a range of more than 0% by weight and less than 1% by weight, based on the total weight of the core layer composition.

[0133] The surface composition forming step (S20) is a step of forming a surface composition comprising a first polymeric resin.

[0134] The surface composition forming step (S20) can be achieved by compounding and extrusion.

[0135] The step of forming the surface composition (S20) may include: mixing the first polymeric resin in a range of 87 to 97% by weight, based on the total weight of the surface composition.

[0136] The surface composition forming step (S20) may further include the step of mixing heat-reflective filler and heat-absorbing filler.

[0137] The surface composition forming step (S20) may further include: mixing 1 to 10% by weight of the heat-reflective filler and 1 to 5% by weight of the heat-absorbing filler based on the total weight of the surface composition.

[0138] The heterogeneous injection step is a step of heterogeneously injecting the core layer composition and the surface layer composition to form the molded body 10.

[0139] Dissimilar injection molding is a method of creating layers by sequentially molding two or more materials of different colors or different colors in a single mold using two or more injection devices, or by simultaneously injecting two different resins using two injection devices. In this embodiment, the molded body 10 can be formed using a dissimilar injection molding process known in the art.

[0140] The heterologous injection step may include: a first injection step (S30) of injecting the surface layer composition; and a second injection step (S40) of injecting the core layer composition. Furthermore, the heterologous injection step may further include: a third injection step (S50) of re-injecting the surface layer composition to remove the core layer composition from the sprue.

[0141] Referring to FIG4, in the first injection step (S30), the surface layer composition can be injected into the cavity 31 of the mold 30 to form the initial surface layer 11'.

[0142] The first injection step (S30) can be performed at a temperature in the range of 200 to 240°C. When the temperature of the first injection step (S30) is below the range, the injection of the surface layer composition cannot be performed smoothly, and when the temperature exceeds the range, there is a concern that the surface layer composition may undergo thermal decomposition.

[0143] In the second injection step (S40), the core layer composition is injected into the cavity 31 of the mold 30 to form the core layer 12, and the initial surface layer 11' can be converted into the surface layer 11.

[0144] The second injection step (S40) can be performed at a temperature in the range of 160 to 180°C. When the temperature of the second injection step (S40) is below the range, the injection of the core layer composition cannot be performed smoothly, and when the temperature exceeds the range, there is a concern that the core layer composition may undergo thermal decomposition.

[0145] Furthermore, when the content of the phase change material contained in the core layer composition is too high, in the second injection step (S40), a flow rate reversal occurs due to the increase in the melt index of the core layer 12, which may cause the positions of the surface layer 11 and the core layer 12 to reverse.

[0146] Through the first injection step (S30) and the second injection step (S40), a sandwich structure in which the surface layer 11 is stacked on both sides of the core layer 12 can be formed.

[0147] The third injection step (S50) is a step of re-injecting the surface layer composition to remove the core layer composition from the injection port, and can be performed selectively.

[0148] According to the method for manufacturing a molded body with thermal control capability according to embodiments of the present invention, a molded body with thermal control capability that can effectively control temperature can be easily manufactured by heterogeneous injection molding without performing an additional microencapsulation process that complicates the process and increases costs.

[0149] The present invention will now be described in more detail through embodiments. However, the following embodiments are merely examples of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0150] [Example] 1. Manufacturing of a molded body with thermal control capability: 65% by weight of polypropylene resin, 10% by weight of talc, 4% by weight of silica, and 1% by weight of butylated hydroxytoluene (BHT) are sequentially added to the hopper 21 of the extrusion device 20 in Figure 3. 20% by weight of N-eicosane is added to the liquid feeder 22. The temperature of the hopper 21 is set to 120°C, and the temperature of the die head 23 of the extrusion device 20 is set to below 180°C. The composition for the core layer is formed by compounding and extrusion.

[0151] 95% by weight of polypropylene resin, 3% by weight of Al2O3 and 2% by weight of CNT are added to the hopper 21 of the extrusion device 20, and a surface composition is formed by compounding and extrusion.

[0152] Using a heterogeneous injection device, the surface layer composition is injected at a temperature of 220°C, and then the core layer composition is injected at a temperature of 180°C, thereby manufacturing a molded article with heat control capability according to an embodiment of the present invention having a sandwich structure having a core layer and a surface layer stacked on both sides of the core layer.

[0153] 2. Characteristics of the molded body with heat control capability: The temperature characteristics of the molded body with heat control capability according to the embodiment of the present invention and the molded body made of polypropylene resin alone (comparative example) are evaluated according to the external temperature change, as shown in FIG5.

[0154] Referring to Figure 5, when the external temperature varies from -30°C to 50°C, it can be confirmed that, compared with the comparative example, the molded body with thermal control capability according to the embodiment exhibits a temperature difference maintenance capability of up to 10°C.

[0155] As shown above, the molded body with thermal control capability according to an embodiment of the present invention, by having a sandwich structure consisting of a core layer and a surface layer containing a phase change material, can achieve a temperature control effect caused by heat storage due to the phase change material contained in the core layer and a desired heat transfer efficiency caused by the heat-reflective filler and the heat-absorbing filler contained in the surface layer. In this way, the phenomenon of easy temperature rise of the molded body is controlled by the latent heat of the phase change material, and thus the indoor ambient temperature can be controlled without the use of electricity. Furthermore, even without encapsulating the phase change material, the phenomenon of easy temperature rise of the molded body can be controlled by the latent heat of the phase change material, and thus the indoor ambient temperature can be controlled without the use of electricity. Moreover, when the molded body with thermal control capability according to an embodiment of the present invention is used as an automotive interior material, by controlling the heat absorption and reflection properties of the interior material, not only can the phenomenon of temperature rise in the vehicle interior caused by radiant heat be controlled, but also the phenomenon of temperature rise in the vehicle interior caused by convective heat can be controlled, thereby improving the efficiency of automotive air conditioning and heaters, and increasing the driving range by improving the thermal efficiency of electric vehicles. Furthermore, according to the method for manufacturing a molded body with thermal control capability according to embodiments of the present invention, a molded body with thermal control capability that can effectively control temperature can be easily manufactured by heterogeneous injection molding without performing an additional microencapsulation process that complicates the process and increases costs.

[0156] As described above, the present invention has been illustrated with reference to the embodiments shown in the accompanying drawings. However, these are merely exemplary, and it should be understood that various modifications and equivalent embodiments are possible based on common knowledge within the art to which this invention pertains. Therefore, the true scope of protection of this invention should be determined by the appended claims and based on the specific content of the invention described above.

[0157] (Industrial Applicability) This invention relates to a molded article with thermal control capability and a method for manufacturing the same, which can be used in industrial fields related to automotive interior materials.

Claims

1. A molded body with thermal control capability, wherein, include: Core layer, the core layer comprising a phase change material; The surface layer is stacked on both sides of the core layer and contains a first polymer resin.

2. The molded article with thermal control capability according to claim 1, characterized in that, The phase change material contains paraffinic hydrocarbons.

3. The molded article with thermal control capability according to claim 1, characterized in that, Based on the total weight of the core layer, the phase change material comprises 15 to 25% by weight.

4. The molded article with thermal control capability according to claim 1, characterized in that, The core layer also includes a second polymer resin, a first filler material, and a second filler material.

5. The molded article with thermal control capability according to claim 4, characterized in that, The second polymeric resin comprises polypropylene, acrylonitrile-butadiene-styrene copolymer, polyamide 6, polycarbonate or a combination thereof, the first filler comprises talc, calcium carbonate or a combination thereof, and the second filler comprises silica, zeolite or a combination thereof.

6. The molded article with thermal control capability according to claim 4, characterized in that, Based on the total weight of the core layer, the core layer comprises 55-70% by weight of the second polymer resin, 10-15% by weight of the first filler material, and 4-5% by weight of the second filler material.

7. The molded article with thermal control capability according to claim 1, characterized in that, The first polymeric resin comprises polypropylene, acrylonitrile-butadiene-styrene copolymer, polyamide 6, polycarbonate, or a combination thereof.

8. The molded article with thermal control capability according to claim 1, characterized in that, Based on the total weight of the surface layer, the first polymeric resin comprises 87 to 97% by weight.

9. The molded article with thermal control capability according to claim 1, characterized in that, The surface layer also includes heat-reflective filler and heat-absorbing filler. The heat-reflective filler includes alumina, spherical aluminum, titanium oxide, zinc oxide, or a combination thereof, and the heat-absorbing filler includes carbon-based fillers.

10. The molded article with thermal control capability according to claim 9, characterized in that, Based on the total weight of the surface layer, the surface layer contains 1 to 10% by weight of the heat-reflective filler and 1 to 5% by weight of the heat-absorbing filler.

11. A method for manufacturing a molded article with thermal control capability, wherein, include: The process includes a core layer composition forming step, which forms a core layer composition comprising a phase change material; a surface layer composition forming step, which forms a surface layer composition comprising a first polymer resin; and a heterogeneous injection step, which heterogeneously injects the core layer composition and the surface layer composition to form a molded article.

12. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The core layer composition forming step includes: mixing the phase change material, the second polymer resin, the first filler material, and the second filler material.

13. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The core layer composition formation step is achieved by compounding and extrusion at a temperature in the range of 120–180°C.

14. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The core layer composition forming step includes: mixing the phase change material in a range of 15 to 25% by weight, based on the total weight of the core layer composition.

15. The method for manufacturing a molded article with thermal control capability according to claim 12, characterized in that, The second polymeric resin comprises polypropylene, acrylonitrile-butadiene-styrene copolymer, polyamide 6, polycarbonate or a combination thereof, the first filler comprises talc, calcium carbonate or a combination thereof, and the second filler comprises silica, zeolite or a combination thereof.

16. The method for manufacturing a molded article with thermal control capability according to claim 12, characterized in that, The core layer composition forming step includes: mixing 55-70% by weight of the second polymer resin, 10-15% by weight of the first filler material and 4-5% by weight of the second filler material based on the total weight of the core layer composition.

17. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The first polymeric resin comprises polypropylene, acrylonitrile-butadiene-styrene copolymer, polyamide 6, polycarbonate, or a combination thereof.

18. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The step of forming the surface layer composition includes: mixing the first polymeric resin in a range of 87-97% by weight, based on the total weight of the surface layer composition.

19. The method for manufacturing a molded article with thermal control capability according to claim 11, characterized in that, The surface composition forming step further includes the step of mixing a heat-reflective filler and a heat-absorbing filler, wherein the heat-reflective filler comprises alumina, spherical aluminum, titanium oxide, zinc oxide or a combination thereof, and the heat-absorbing filler comprises carbon-based fillers.

20. The method for manufacturing a molded article with thermal control capability according to claim 19, characterized in that, The step of forming the surface layer composition includes: mixing 1 to 10% by weight of the heat-reflective filler and 1 to 5% by weight of the heat-absorbing filler based on the total weight of the surface layer composition.

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