Transparent dielectric heater composition and transparent dielectric heater

Abstract

The present invention relates to a transparent dielectric heater composition and a thermochromic dielectric heater. One embodiment exhibits high performance and high flexibility by addition of PC and EC. A dielectric heater composition according to an embodiment of the present invention comprises: a polymer resin; a main plasticizer; propylene carbonate (PC); and ethylene carbonate (EC).

Description

Transparent dielectric heater composition and transparent dielectric heater

[0001] The present invention relates to a transparent dielectric heater composition and a transparent dielectric heater. One embodiment has high performance and high flexibility by adding PC and EC.

[0002] The present invention is the result of research conducted with funding from the Ministry of Science and ICT and supported by the National Research Foundation of Korea (RS-2024-00348475).

[0003] Flexible transparent heaters are a technology that provides high thermal conductivity performance through electrical heat generation while maintaining a thin and flexible structure. These heaters can be used in various fields such as electronic devices, displays, and wearable devices, and their transparent and flexible properties are particularly useful in applications such as displays or touchscreens.

[0004] Conventional flexible transparent heater technology primarily utilizes materials such as metal nanowires, carbon nanotubes (CNT), and graphene to form transparent electrodes and fabricate heaters based on them. While this approach offers excellent electrical properties, metal nanowires and carbon nanotubes are expensive, have poor transparency, and suffer from performance degradation due to reduced resistance caused by mechanical deformation. In particular, there is a problem in achieving uniform heat distribution. Furthermore, their lack of durability against mechanical deformation can lead to performance degradation during long-term use.

[0005] In particular, plasticizers used in conventional technology are primarily materials such as DBA (Dioctyl Sebacate). While dielectric layers using these plasticizers are effective in imparting flexibility, their dielectric performance is relatively insufficient. This issue degrades the thermal conductivity of flexible heaters, leading to increased power consumption or limitations in practical applications due to the inability to provide sufficient heat.

[0006] The present invention aims to provide a dielectric heater composition capable of manufacturing a dielectric heater having high transparency.

[0007] In addition, the dielectric heater provided by the present invention has excellent dielectric properties.

[0008] In addition, the dielectric heater provided by the present invention has excellent heater performance and thermal stability.

[0009] A dielectric heater composition according to an embodiment of the present invention comprises a polymer resin; a main plasticizer; propylene carbonate (PC) and ethylene carbonate (EC).

[0010] The combined content ratio of the polymer resin, the main plasticizer, propylene carbonate, and ethylene carbonate may be 1:5.5 to 1:6.5 based on weight.

[0011] The combined content ratio of the above main plasticizer, propylene carbonate, and ethylene carbonate may be 2.5:1 to 3.5:1 based on weight.

[0012] The content ratio of the above propylene carbonate and ethylene carbonate may be 1:8.5 to 1:9.0 based on weight.

[0013] The content ratio of the polymer resin and the main plasticizer may be 1:4 to 1:5 based on weight.

[0014] The combined content ratio of the polymer resin, propylene carbonate, and ethylene carbonate may be 1:1 to 1:2 based on weight.

[0015]

[0016] A method for manufacturing a dielectric heater layer according to an embodiment of the present invention comprises the steps of: dissolving a polymer resin in a solvent to prepare a polymer resin solution; mixing a main plasticizer, propylene carbonate, and ethylene carbonate with the polymer resin solution to prepare a mixture; and drying the mixture.

[0017] The combined content ratio of the polymer resin, the main plasticizer, propylene carbonate, and ethylene carbonate added in the step of preparing the above mixture may be 1:5.5 to 1:6.5 based on weight.

[0018]

[0019] A dielectric heater according to an embodiment of the present invention includes the dielectric heater layer described above.

[0020] A dielectric heater composition according to an embodiment of the present invention can manufacture a dielectric heater having high transparency.

[0021] In addition, the dielectric heater provided by the present invention has excellent dielectric properties.

[0022] In addition, the dielectric heater provided by the present invention has excellent heater performance and thermal stability.

[0023] FIG. 1 is a flowchart of a method for manufacturing a transparent dielectric heater according to an embodiment of the present invention.

[0024] Figure 2 shows the results of measuring the dielectric constant of the dielectric heater layer.

[0025] FIG. 3 shows the results of measuring the dielectric constant of a dielectric heater layer of another embodiment.

[0026] Figure 4 shows the results of the loss factor analysis of the dielectric heater layer.

[0027] Figure 5 is the result of the stress-strain curve analysis of the dielectric heater layer of another embodiment.

[0028] Figure 7 shows the results of measuring the transmittance of the dielectric heater layer, gel electrode, etc.

[0029] Figure 8 is a photograph showing the temperature change according to the applied voltage and extension of the dielectric heater.

[0030] Figure 9 is a graph showing the change in temperature over time according to the applied voltage and elongation of the dielectric heater.

[0031] Hereinafter, preferred embodiments of the present invention are described as follows with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0032]

[0033] A dielectric heater composition according to an embodiment of the present invention comprises a polymer resin; a main plasticizer; propylene carbonate (PC) and ethylene carbonate (EC).

[0034]

[0035] The above polymer resin serves as a substrate for the dielectric heater. The polymer resin acts as an electrical insulator, providing stability during the process of converting electrical energy into thermal energy, and imparts flexibility, enabling its use in various application environments. Furthermore, the polymer resin enhances thermal conductivity. Additionally, the polymer resin possesses high heat resistance, ensuring that its physical and chemical properties are maintained even during prolonged use, thereby maintaining the heater's performance stably.

[0036] The above polymer resin may be polyvinyl chloride (PVC), polyurethane (PU), polysiloxane (silicone resin), polyethylene terephthalate (PET), etc., and preferably may be polyvinyl chloride.

[0037]

[0038] The above-mentioned primary plasticizer improves the mechanical properties of the polymer resin and makes the material more flexible, thereby enhancing processability and processability. Preferably, the above-mentioned primary plasticizer may be dibutyl adipate (DBA).

[0039] The content ratio of the polymer resin and the main plasticizer may be 1:4 to 1:5 based on weight. If the content of the main plasticizer is low, flexibility and mechanical properties decrease, whereas if it is too high, there is a problem of reduced mechanical strength and reduced heat resistance.

[0040]

[0041] The above propylene carbonate (PC) and ethylene carbonate (EC) function as auxiliary plasticizers. The above propylene carbonate and ethylene carbonate work together with the main plasticizer to improve the flexibility of PVC, improve dielectric performance, and increase thermal stability.

[0042] The above propylene carbonate serves to enhance electrical properties by improving dielectric performance. This enables the dielectric heater to generate higher heat and utilize power efficiently. The above propylene carbonate can be represented by Structural Formula 1.

[0043] [Structural Formula 1]

[0044]

[0045] The above ethylene carbonate (EC) is a material having a high dielectric constant, which increases the ratio of energy dissipated from electrical energy to thermal energy. The above ethylene carbonate can be represented by structural formula 2.

[0046] [Structural Formula 2]

[0047]

[0048] The content ratio of the above propylene carbonate and ethylene carbonate may be 1:8.5 to 1:9.0 based on weight. When the content ratio of propylene carbonate is high, dielectric properties deteriorate and mechanical strength decreases, and when the content of ethylene carbonate is high, there is a problem of reduced flexibility.

[0049] The combined content ratio of the polymer resin and the main plasticizer, propylene carbonate, and ethylene carbonate may be 1:5.5 to 1:6.5 based on weight, and the combined content ratio of the polymer resin and the propylene carbonate and ethylene carbonate may be 1:1 to 1:2 based on weight, preferably 1:1.5 to 1:1.7. If the combined content ratio of the main plasticizer, propylene carbonate, and ethylene carbonate is high, dielectric properties are improved, but there is a problem that mechanical properties deteriorate due to the inclusion of a large amount of plasticizer, and conversely, if the content ratio is low, dielectric properties are not improved.

[0050] The combined content ratio of the above main plasticizer, propylene carbonate, and ethylene carbonate may be 2.5:1 to 3.5:1 based on weight. If the combined content ratio of propylene carbonate and ethylene carbonate is too high, exceeding 50% of the main plasticizer by weight, water forms in the manufactured dielectric heater layer, thereby reducing dielectric performance; conversely, if the content ratio is low, dielectric properties are not improved.

[0051]

[0052] A method for manufacturing a dielectric heater layer according to an embodiment of the present invention comprises the steps of: dissolving a polymer resin in a solvent to prepare a polymer resin solution; mixing a main plasticizer, propylene carbonate, and ethylene carbonate with the polymer resin solution to prepare a mixture; and drying the mixture.

[0053]

[0054] In the step of preparing a polymer resin solution by dissolving a polymer resin in the above solvent, the polymer resin is the one described above, and the solvent may be an organic solvent capable of dissolving the polymer resin. Preferably, the solvent may be tetrahydrofuran (THF). This step may be performed at room temperature, and a sufficient amount of solvent to dissolve the polymer resin may be used.

[0055]

[0056] In the step of preparing the above mixture, each component is as previously described, and the content of each component added in this step is also the same as previously described. This step can be performed by introducing each component into a stirrer and stirring.

[0057]

[0058] The step of drying the above mixture can be performed by pouring the mixture into a mold or Petri dish, etc., and drying the solvent by applying room temperature or a constant temperature.

[0059]

[0060] A dielectric heater according to an embodiment of the present invention includes the dielectric heater layer described above. The dielectric heater may further include components such as electrodes in contact with the transparent dielectric heater layer.

[0061]

[0062] Experiment for Optimizing the PC:EC Content Ratio

[0063] Example: Preparation of a dielectric assisted plasticizer

[0064] Example 1 (PC:EC 1:9): 9g of ethylene carbonate (DAEJUNG) was added to 1g of propylene carbonate (Sigma Aldrich) and sonication was performed for 30 minutes.

[0065]

[0066] Example 2 (PC:EC 1:7): ​​Prepared in the same manner as Example 1, except that 1 g of PC and 7 g of EC were added.

[0067]

[0068] Example 3 (PC:EC 1:5): Prepared in the same manner as Example 1, except that 1 g of PC and 5 g of EC were added.

[0069]

[0070] Example 4 (PC:EC 1:3): Prepared in the same manner as Example 1, except that 1 g of PC and 3 g of EC were added.

[0071]

[0072] Example 5 (PC:EC 1:1): Prepared in the same manner as Example 1, except that 1 g of PC and 1 g of EC were added.

[0073]

[0074] In manufacturing the dielectric heater layer, if the EC content exceeded 9 times that of PC, the PC did not dissolve the EC. Therefore, the maximum ratio of PC to EC content was set to 1:9.

[0075]

[0076] Experimental Example: Measurement of Dielectric Constant

[0077] The dielectric constants of Examples 1 to 5 were measured using an Impedance Analyzer from Solartron, and the results are shown in Figure 2.

[0078] Referring to Figure 2, it can be seen that the dielectric constant of Example 1 is the best.

[0079]

[0080] Main Plasticizer: Experiment for Optimizing Content Ratio of PC and EC

[0081] Example: Preparation of a dielectric heater layer

[0082] Example 6 (D-PE6(6:0)): A PVC solution was prepared by dissolving 0.8787 g of PVC powder (Scientific Polymer Products, Inc., Mw 275,000) in 50 mL of tetrahydrofuran. 5.2722 g of DBA (TCI), 0 g of PC (Sigma Aldrich), and 0 g of EC (DAEJUNG) were added to the PVC solution, and sonication was performed for 30 minutes. The mixture was poured into a Petri dish and the solvent was removed by solution casting to prepare a dielectric heater layer.

[0083]

[0084] Example 7 (D-PE6(6:1)): Prepared in the same manner as Example 6, except that 1.0125g of PVC, 5.0627g of DBA, 0.1012g of PC, and 0.9113g of EC were added.

[0085]

[0086] Example 8 (D-PE6(6:2)): Prepared in the same manner as Example 6, except that 1.0960 g of PVC, 4.9321 g of DBA, 0.1096 g of PC, and 0.9864 g of EC were added.

[0087]

[0088] Example 9 (D-PE6(6:3)): Prepared in the same manner as Example 6, except that 1.1966 g of PVC, 4.7795 g of DBA, 0.1194 g of PC, and 1.0750 g of EC were added.

[0089]

[0090] Experimental Example: Measurement of Dielectric Constant

[0091] The dielectric constants of Examples 6 to 9 were measured in the same manner as the previous method, and the results are shown in Fig. 3.

[0092] Referring to Fig. 3, it can be seen that the dielectric constant of Example 8 is the best. For reference, in Example 9, it is determined that the dielectric properties decreased because water was generated in the dielectric heater layer.

[0093]

[0094] Polymer Resin: Experiment for Optimizing Content Ratios of Main Plasticizer, PC, and EC

[0095] Example: Preparation of a dielectric heater layer

[0096] Example 10 (D-PE2): A PVC solution was prepared by dissolving 2.1687 g of PVC powder (Scientific Polymer Products, Inc., Mw 275,000) in 100 mL of tetrahydrofuran. 4.3684 g of DBA (TCI), 0.2169 g of PC (Sigma Aldrich), and 1.9518 g of EC (DAEJUNG) were added to the PVC solution, and sonication was performed for 30 minutes. The mixture was poured into a Petri dish and the solvent was removed by solution casting to prepare a dielectric heater layer.

[0097]

[0098] Example 11 (D-PE4): Prepared in the same manner as Example 10, except that 1.4561g of PVC, 4.3684g of DBA, 0.1456g of PC, and 1.3105g of EC were added.

[0099]

[0100] Example 12 (D-PE6): Prepared in the same manner as Example 10, except that 1.0960 g of PVC, 4.9321 g of DBA, 0.1096 g of PC, and 0.9864 g of EC were added.

[0101]

[0102] Example 13 (D-PE8): Prepared in the same manner as Example 10, except that 0.8787 g of PVC, 5.2722 g of DBA, 0.0879 g of PC, and 0.7908 g of EC were added.

[0103]

[0104] Experimental Example: Measurement of Dissipation Factor

[0105] The loss coefficients of Examples 10 to 13 were measured using an Impedance Analyzer from Solartron, and the results are shown in Fig. 4.

[0106] Referring to Fig. 4, Examples 12 and 13 showed high loss coefficients, indicating that they are suitable for dielectric heaters requiring high dielectric properties.

[0107]

[0108] Experimental Example: Stress-Strain Curve Analysis

[0109] The stress-strain of Examples 10 to 13 was analyzed using the same method as described above, and the results are shown in Fig. 5.

[0110] Referring to FIG. 5, it can be seen that the mechanical properties of Example 12 are the best, and the mechanical properties of Example 13 are significantly poor.

[0111]

[0112] Experimental Example: Measurement of Pyrolysis Temperature

[0113] The pyrolysis temperatures of Examples 10 to 13 were measured using Perkin Elmer’s TGA 4000, and the results are shown in Fig. 6.

[0114] Referring to FIG. 6, the pyrolysis temperature in all embodiments is 200 to 300 ℃, and in particular, the pyrolysis temperature of Examples 12 and 13 is high, so it can be confirmed that there is no problem with using it as a heater.

[0115]

[0116] Experimental Example: Transmittance Measurement

[0117] The transmittance was measured for Example 12 (P(PVC gel)), the gel electrode (H(Hydrogel)), the stack of Example 12-gel electrode (HP), and the stack of gel electrode-Example 12-gel electrode (HPH), respectively, and the results are shown in Fig. 7.

[0118] For reference, the gel electrode was prepared by adding 1.98g of acrylamide, 2.38g of LiCl, and 0.0021g of N,N'-methylenebisacrylamide to 5.6323g of distilled water and performing ultrasonic treatment for 30 minutes, adding 0.0056g of ammonium persulfate and 0.00655g of tetramethylethylenediamine on ice to slow down the curing speed, injecting the mixture into a mold prepared with a pre-gel, curing it in a UV curer for 10 minutes, and then reversing the process to manufacture the back electrode.

[0119] In addition, to laminate the dielectric heater layer and the gel electrode of Example 12, a solution of ethanol and benzophenone mixed in a 1:9 ratio was spray-coated on one or both sides of the dielectric heater layer, and then the gel electrode was placed to laminate them.

[0120] Referring to Fig. 7, it can be seen that the transmittance is excellent in all objects.

[0121]

[0122] Experiment on the characteristics of dielectric heaters

[0123] Manufacturing Example: Manufacturing of an oil field heater

[0124] A dielectric heater was manufactured using the dielectric heater layer of Example 12. After spray-coating a solution of ethanol and benzophenone mixed in a 1:9 ratio on both sides of the dielectric heater layer of Example 12, the previously prepared gel electrodes were placed on each side.

[0125]

[0126] Experimental Example: Observation of temperature change according to applied voltage and elongation

[0127] Using the transparent dielectric heater manufactured in the example, 1 cm 2 X 1 cm 2After cutting to the size of [size], elongation was performed from 0% to 300% in 100% increments under conditions of 350Hz and 350V, and the color change at this time was observed and the results are shown in Figures 8 and 9.

[0128] Referring to Figures 8 and 9, as the thickness of the dielectric layer decreases with increasing heater, the electric field increases and the saturation temperature also increases.

[0129]

[0130] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, without departing from the technical spirit of the invention, and such are also to be considered to fall within the scope of the present invention.

[0131]

Claims

1. Polymer resin; Plasticizer; Propylene carbonate (PC) and Containing ethylene carbonate (EC), Oilfield heater composition.

2. In Paragraph 1, The combined content ratio of the above polymer resin and the above main plasticizer, propylene carbonate, and ethylene carbonate is 1:5.5 to 1:6.5 based on weight, Oilfield heater composition.

3. In Paragraph 1, The combined content ratio of the above main plasticizer, propylene carbonate, and ethylene carbonate is 2.5:1 to 3.5:1 by weight, Oilfield heater composition.

4. In Paragraph 1, The content ratio of the above propylene carbonate and ethylene carbonate is 1:8.5 to 1:9.0 based on weight, Oilfield heater composition.

5. In Paragraph 1, The content ratio of the polymer resin and the main plasticizer is 1:4 to 1:5 based on weight, Oilfield heater composition.

6. In Paragraph 1, The combined content ratio of the above polymer resin, propylene carbonate, and ethylene carbonate is 1:1 to 1:2 based on weight, Oilfield heater composition.

7. A step of preparing a polymer resin solution by dissolving a polymer resin in a solvent; A step of preparing a mixture by mixing a main plasticizer, propylene carbonate, and ethylene carbonate into the above polymer resin solution, and A step comprising drying the above mixture, Method for manufacturing an oil field heater layer.

8. In Paragraph 7, The combined content ratio of the polymer resin, the main plasticizer, propylene carbonate, and ethylene carbonate added in the step of preparing the above mixture is 1:5.5 to 1:6.5 based on weight, Method for manufacturing an oil field heater layer.

9. A dielectric heater comprising the dielectric heater layer of claim 7.

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