JP2021008390A - Titanium oxide material, heat storage/radiation device, and method for producing titanium oxide material - Google Patents

Abstract

To provide a titanium oxide material that contains trititanium pentoxide particles and readily exhibits excellent heat-absorbing properties.SOLUTION: A titanium oxide material contains trititanium pentoxide. The trititanium pentoxide has a phase transition temperature for phase transition to occur between solid phases, and has a median size D50 of 3 μm or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a titanium oxide-based material, a heat storage / heat dissipation device, and a method for manufacturing a titanium oxide-based material. More specifically, the present invention relates to a titanium oxide-based material, a storage / heat dissipation device including the titanium oxide-based material, and a method for producing the titanium oxide-based material.

When trititanium pentoxide is heated, it undergoes a phase transition between solid phases and absorbs heat accordingly. Trititanium pentoxide can be used as a heat storage and heat dissipation material by utilizing the characteristic of endothermic heat due to the phase transition between solid phases (Patent Document 1).

International Publication No. 2015/050269

The inventors examined the use of various forms of trititanium pentoxide, and attempted to develop a device utilizing the endothermic properties of particulate trititanium pentoxide.

However, as the inventors proceeded with the development, it was found that the amount of heat absorbed by the phase transition of particulate trititanium pentoxide is low, and it is difficult to obtain a device having a stable heat storage and heat dissipation function.

An object of the present invention is to provide a titanium oxide-based material containing trititanium pentoxide particles and easily exhibiting good endothermic characteristics, a heat storage and heat dissipation device provided with the titanium oxide-based material, and a method for producing the titanium oxide-based material. That is.

The titanium oxide-based material according to one aspect of the present disclosure contains trititanium pentoxide particles. The trititanium pentoxide particles have a phase transition temperature at which a phase transition occurs between solid phases and have a median diameter D50 of 3 μm or more.

The heat storage / heat dissipation device according to one aspect of the present disclosure includes the titanium oxide-based material.

The method for producing a titanium oxide-based material according to one aspect of the present disclosure is a method for producing a titanium oxide-based material containing trititanium pentoxide particles, and includes a step of pulverizing massive trititanium pentoxide.

According to the titanium oxide-based material and the heat storage / heat dissipation device of the present disclosure, it contains trititanium pentoxide particles and easily exhibits good endothermic characteristics.

According to the method for producing a titanium oxide-based material of the present disclosure, a titanium oxide-based material containing trititanium pentoxide particles and easily exhibiting good endothermic properties can be obtained.

FIG. 1 is a graph showing an example of the relationship between the temperature and the amount of heat absorbed when the titanium oxide-based material according to the present embodiment is heated and cooled. FIG. 2 is a graph plotting the amount of heat absorbed at each average particle size (median diameter D50) of the trititanium pentoxide particles in the titanium oxide-based materials of Examples 1 to 6. 3A to 3C are SEM images showing an example of the state of the trititanium pentoxide particles of Examples 1 and 4 after pulverization. FIG. 3D is an SEM image showing an example of the state of the trititanium pentoxide particles of Example 6. 4A to 4F are graphs showing examples of particle size distribution of trititanium pentoxide particles of Examples 1 to 5 and Comparative Example 1. FIG. 5 is a schematic view showing an example of the heat storage / heat dissipation device of one embodiment of the present embodiment.

The titanium oxide-based material according to one embodiment of the present embodiment contains trititanium pentoxide particles. The trititanium pentoxide particles have a phase transition temperature at which a phase transition occurs between solid phases and have a median diameter D50 of 3 μm or more. When the median diameter of the trititanium pentoxide particles is 3 μm or more, it has an endothermic property that it absorbs heat due to the phase transition due to heating, and after the heat-absorbing trititanium pentoxide dissipates heat, it absorbs heat when it is heated again. .. Therefore, the titanium oxide-based material of the present embodiment tends to exhibit good endothermic characteristics even if it contains particles of trititanium pentoxide. Therefore, the titanium oxide-based material can be stably used as a heat storage and heat dissipation material even if it is used for a heat storage and heat storage device having a stable heat storage and heat dissipation function.

The titanium oxide-based material of the present embodiment will be specifically described.

Due to the difference in crystal structure, trititanium pentoxide includes β-trititanium pentoxide (hereinafter, also referred to as β phase) having a β-type monoclinic crystal structure and α having an α-type rectangular crystal structure. There are −trititanium pentoxide (hereinafter, also referred to as α phase) and λ−trititanium pentoxide (hereinafter, also referred to as λ phase) having a λ-type monoclinic crystal structure. The trititanium pentoxide phase transitions to the α phase when the β phase is heated, and to the β phase when the α phase is cooled. Further, the trititanium pentoxide particles undergo a phase transition in the same manner when the β phase is heated again and then cooled. That is, the titanium oxide-based material containing the trititanium pentoxide particles has thermal reversibility.

The trititanium pentoxide particles of the present embodiment contain a β phase, and the β phase is heated to the α phase at the first endothermic phase transition temperature, for example, as shown by the thermal behavior of the broken line shown in FIG. It undergoes a phase transition to and absorbs the first endothermic amount. When the trititanium pentoxide particles are heated again after the α phase that has undergone a phase transition at the first endothermic phase transition temperature is cooled and undergoes a phase transition to the β phase, the thermal behavior of the solid line shown in FIG. As described above, the β phase undergoes a phase transition to the α phase at the second endothermic phase transition temperature, and absorbs the second endothermic amount. Then, it is preferable that the second heat absorption amount is larger than the first heat absorption amount of the trititanium pentoxide particles. In this case, the titanium oxide-based material can maintain a high endothermic amount even if it contains trititanium pentoxide particles, and therefore tends to exhibit good endothermic characteristics.

Here, the "first endothermic phase transition temperature" is the temperature at which the β phase of the trititanium pentoxide particles undergoes a phase transition to the α phase for the first time by heating. The "second heat-absorbing phase transition temperature" means that the β-phase of trititanium pentoxide undergoes a phase transition to the α-phase at least once by heating, is cooled, and undergoes a phase transition from the α-phase to the β-phase, and then is heated again. This is the temperature at which the phase transition from the β phase to the α phase occurs. Further, the "first heat absorption amount" is defined as an arbitrary baseline drawn in the graph showing the thermal behavior of the β phase of the trititanium pentoxide particles based on the DSC (Differental scanning calorimetry) measurement of the trititanium pentoxide. Sometimes it refers to the amount of heat absorbed calculated from the heat absorption curve when heat is absorbed at the first phase transition temperature, and the "second amount of heat absorbed" is the β phase of trititanium pentoxide particles based on DSC measurement. It refers to the amount of heat absorbed calculated from the heat absorption curve when heat is absorbed at the second phase transition temperature when an arbitrary baseline is drawn in the graph showing thermal behavior. When the first endothermic phase transition temperature and the second endothermic phase transition temperature are not particularly distinguished, they are also simply referred to as "endothermic phase transition temperature", and when the first endothermic amount and the second endothermic amount are not particularly distinguished. Is also simply referred to as "heat absorption". The DSC measurement can be performed using an appropriate measuring device, and the measurement conditions may be, for example, the conditions presented in the examples described later.

In the present embodiment, the β phase of trititanium pentoxide particles before absorbing heat at the first endothermic phase transition temperature and the pentoxide undergoing phase transition by absorbing heat at the first endothermic phase transition temperature and then radiating heat after passing through the α phase. The endothermic characteristics are different from the β phase of the trititanium particles. In the trititanium pentoxide particles of the present embodiment, the β phase undergoes a phase transition at the second heat absorbing phase transition temperature, then undergoes a phase transition to the α phase, and the α phase is further cooled to undergo a phase transition to the β phase, and then again. When heated, for example, the heat-absorbing phase transition temperature and the amount of heat-absorbing when the phase transition by heating and cooling is performed two or more times are substantially the same as the second heat-absorbing phase transition temperature and the second heat-absorbing amount.

In the present embodiment, the second endothermic phase transition temperature of the trititanium pentoxide particles is lower than the first endothermic phase transition temperature. The second endothermic phase transition temperature is, for example, 191 ° C. or lower. In this case, when the titanium oxide-based material is subjected to heat reaching a relatively high temperature such as 200 ° C. or higher, the trititanium pentoxide particles having a second endothermic phase transition temperature absorb heat from a lower temperature. can do.

The second heat absorption amount of the trititanium pentoxide particles in the titanium oxide-based material of the present embodiment is 20 J / g or more. Therefore, the titanium oxide-based material can exhibit good endothermic properties.

It is also preferable that the first heat absorption amount of the trititanium pentoxide particles is 20 J / g or more. In this case, the titanium oxide-based material can have particularly excellent endothermic properties. Therefore, the titanium oxide-based material can be easily used as a heat storage and heat dissipation material without controlling the endothermic characteristics by heating at a temperature exceeding the first endothermic phase transition temperature.

The second heat absorption amount of the trititanium pentoxide particles is preferably larger than the first heat absorption amount. In this case, the titanium oxide-based material can be suitably used as a heat storage and heat dissipation material having an excellent heat absorption amount.

The endothermic characteristics of the trititanium pentoxide particles in the titanium oxide-based material as described above can be realized by adjusting the particle size of the titanium pentoxide particles.

As already described, the titanium oxide-based material according to the present embodiment contains trititanium pentoxide particles. The median diameter D50 of the trititanium pentoxide particles is 3 μm or more. The median diameter D50 is an average particle diameter calculated from a particle size distribution measured on a volume basis by a laser diffraction / scattering method, and the cumulative frequency in the particle size distribution is 50%. The median diameter D50 can be measured using, for example, a measuring device such as a microtrack particle size distribution measuring device (model number MT3000II) manufactured by Nikkiso Co., Ltd.

The median diameter D50 of the trititanium pentoxide particles is preferably 15 μm or more. When the median diameter D50 of the trititanium pentoxide particles is 15 μm or more, the first heat absorption amount of the trititanium pentoxide particles is larger than that when the median diameter is less than 15 μm. Therefore, the titanium oxide-based material is good because it can achieve a higher endothermic amount even if the trititanium pentoxide particles do not undergo a phase transition from the β phase to the α phase at the first endothermic phase transition temperature. Has endothermic properties. Therefore, the titanium oxide-based material is easy to use as a heat storage and heat dissipation material. Further, in this case, for example, when applying a titanium oxide-based material to a storage / heat dissipation device or the like, it is possible to make it difficult for the thermal history to vary. The upper limit of the median diameter D50 of the trititanium pentoxide particles is preferably 500 μm or less, and more preferably 100 μm or less.

Further, when the median diameter D50 of the trititanium pentoxide particles is 3 μm or more and less than 15 μm, the first heat absorption amount is very small as compared with the second heat absorption amount. Therefore, the titanium oxide-based material containing the trititanium pentoxide particles having a median diameter D50 of 3 μm or more and less than 15 μm is high because it is heated beyond the second endothermic phase transition temperature by passing heat dissipation. It may have an endothermic amount. Therefore, the titanium oxide-based material can be applied according to the above endothermic characteristics. For example, if a titanium oxide-based material having the above characteristics is used, a resin containing a component of a thermosetting resin such as an epoxy resin and a silicone resin, which requires heat treatment at a temperature exceeding the endothermic phase transition temperature two or more times. In the material, the amount of heat given to the material can be controlled by the first heating and the second heating. Further, when the titanium oxide-based material is used, the first and second heat absorption amounts (that is, the first heat absorption amount and the second heat absorption amount) are evaluated without using an optical analyzer or the like. It can also be used as a measurement system capable of evaluating the size of trititanium pentoxide particles only by measuring the calorific value of the titanium oxide-based material or the composition containing the titanium oxide-based material as a component. Further, when the median diameter D50 of the trititanium pentoxide particles is 3 μm or more and less than 15 μm, it is possible to improve the processability when molding the titanium oxide-based material. The reason for exhibiting the above-mentioned endothermic characteristics when the median diameter D50 is 3 μm or more and less than 15 μm is considered as follows, for example. For example, the crystal lattice is disturbed by the trititanium pentoxide particles receiving mechanical energy or thermal energy from the surroundings in the process of reducing the particle size of the trititanium pentoxide particles by the crushing step described later for the manufacturing method or the like. , The proportion of β phase that causes thermal vibration is reduced, and the amount of heat that can be absorbed is relatively reduced. However, after passing through the first endothermic phase transition temperature, it becomes the α phase, and when it is subsequently dissipated, it becomes the β phase in which the disorder of the crystal lattice is recovered, that is, it returns to the endothermic phase again. As a result, it is considered that the second endothermic amount can be increased when the β phase is heated to a temperature exceeding the second endothermic phase transition temperature. It is more preferable that the median diameter D50 of the trititanium pentoxide particles is 3 μm or more and 11 μm or less. The results of confirming the relationship between the particle size (median diameter D50) and the endothermic characteristics of the titanium oxide-based material containing the trititanium pentoxide particles will be presented in the examples below.

As described above, the titanium oxide-based material according to the present embodiment can have different endothermic characteristics depending on the particle size of the trititanium pentoxide particles, and the phase transition accompanied by heat absorption and heat dissipation is repeatedly performed by heating and cooling. It is also possible. Therefore, it can be suitably used as a heat storage and heat dissipation material having a function of repeatedly absorbing and radiating heat. Further, the titanium oxide-based material can store the heat history including the temperature and the amount of heat transferred by heating and cooling.

The titanium oxide-based material according to the present embodiment may contain components other than the trititanium pentoxide particles having a median diameter D50 of 3 μm or more described above, as long as the effects of the present disclosure are not impaired. For example, the titanium oxide-based material may contain trititanium pentoxide particles that undergo a phase transition to λ-trititanium pentoxide by heating. Further, for example, the titanium oxide-based material may contain an oxide containing other titanium, or may contain a component other than the oxide containing titanium.

In the above, the case where the titanium oxide-based material is applied to the heat storage and heat dissipation material has been described as an example, but the present invention is not limited to this, and it can be applied as an appropriate material depending on the purpose, for example, an optical material, a semiconductor material, and the like. And may be used for electronic materials and the like.

[Manufacturing method of titanium oxide-based material]
The method for producing the titanium oxide-based material of the present embodiment will be described.

It is a method for producing a titanium oxide-based material containing trititanium pentoxide particles, and the method for producing a titanium oxide-based material includes a step of pulverizing massive trititanium pentoxide. Therefore, the titanium oxide-based material can have absorption and heat dissipation characteristics according to the particle size of the trititanium pentoxide particles.

The method for pulverizing the massive trititanium pentoxide is not particularly limited, and examples thereof include a planetary ball mill, an attritor mill, a bead mill, and a hammer mill. When pulverizing, it may be a dry type or a wet type. In addition, "lumpy" means a shape that is not particulate, and "lumpy" includes, for example, one having a maximum particle size of 0.5 mm or more.

Hereinafter, a case where massive trititanium pentoxide is pulverized with a wet ball mill will be described as an example. However, the method for producing a titanium oxide-based material is not limited to this.

First, a bulk trititanium pentoxide as a raw material having appropriate dimensions is prepared. The massive trititanium pentoxide used as a raw material may be obtained by synthesizing it by a chemical reaction or the like, or may be commercially available. The shape and size of the massive trititanium pentoxide are not particularly limited, but for example, the particle size of each of the massive trititanium pentoxide may be 0.8 mm or more and 4.0 mm or less. The raw material is placed in a container made of, for example, zirconia, and then water is added.

Subsequently, a zirconia ball for crushing is put into the container, and then the container is covered and placed in a crushing device (for example, a planetary ball mill). The number, material, and dimensions of the balls may be adjusted as appropriate. Examples of the crushing device include a planetary ball mill manufactured by Fritsch (model number P-5). The raw material trititanium pentoxide can be pulverized by appropriately adjusting the rotation speed and the processing time of the pulverizer. The conditions for pulverization can be, for example, a rotation speed of 150 rpm or more and 200 rpm or less. When the rotation speed is 150 rpm or more, the massive trititanium pentoxide particles can be efficiently pulverized. Further, the pulverization processing time can be 5 minutes or more and 120 minutes or less.

As a result, trititanium pentoxide particles having an appropriate particle size in the titanium oxide-based material can be obtained. The average particle size (median diameter D50) of the obtained trititanium pentoxide particles is calculated from the results obtained by the particle size distribution measurement as described above. The trititanium pentoxide particles obtained by the method for producing a titanium oxide-based material of the present embodiment can have an appropriate average particle size (median diameter D50) by being pulverized.

[Heat storage device]
The outline of the heat storage / heat storage device 1 according to the present embodiment will be described.

The heat storage / heat storage device 1 includes the titanium oxide-based material described above. The heat storage / heat storage device 1 has a function of absorbing heat around the heat storage / heat storage device 1. That is, since the heat storage / heat storage device 1 of the present embodiment can absorb heat and can store the absorbed heat, it can be applied to a heat storage device for storing heat and a device such as a heat storage / heat storage device. In this case, the heat storage / heat storage device 1 can function as an endothermic device. Specifically, in the heat storage / heat dissipation device 1, for example, the temperature of the heat storage / heat storage device 1 rises due to the transfer of ambient heat, and the titanium oxide-based material in the heat storage / heat dissipation device 1 reaches a temperature exceeding the phase transition temperature. When it reaches, it absorbs heat. Then, the heat storage / heat dissipation device 1 can store the absorbed heat. As a result, the heat storage / heat dissipation device 1 has the temperature of the electronic component, the electronic device, the electronic device, etc. due to the heat generated from the heat generating portion of the electronic component, the electronic device, the electronic device, etc., around the storage / heat dissipation device 1. Even when the temperature rises, the heat storage and heat storage device 1 can prevent the ambient temperature from rising to a high temperature. Therefore, the heat storage / heat dissipation device 1 can suppress the temperature of the surrounding heat-generating parts and the like from rising too high (runaway due to heat generation, etc.).

It is also preferable that the heat storage / heat dissipation device 1 has a function of dissipating the heat stored in the titanium oxide-based material. In this case, the heat storage / heat dissipation device 1 can function as a heat dissipation (heat generation) device. Therefore, the heat storage / heat dissipation device 1 can be applied to, for example, a heat supply device that requires heat supply. Examples of the heat supply device include a fluid heating device that heats a fluid in an air conditioner mounted on a vehicle or the like, a fluid heating device that heats a working fluid flowing in an internal combustion engine, and a fluid in a fluid flow path such as a semiconductor device. Examples include a heating device. The heat dissipation of the heat storage / heat dissipation device 1 is to cool the α-phase trititanium pentoxide particles that have been put into a heat storage state by applying heat to the titanium oxide-based material, and to cool the temperature above the temperature at which the trititanium pentoxide particles undergo a phase transition. Can be achieved with. As described above, the α-phase trititanium pentoxide in the heat storage state can dissipate the heat absorbed by cooling, but unless it is rapidly cooled, the amount of heat absorbed at the phase transition temperature during heating is released at once. It's not a thing. The term "quenching" as used herein means, for example, a case of cooling at a cooling rate of 100 ° C./min or more.

The trititanium pentoxide particles of the titanium oxide-based material in the storage / heat dissipation device 1 may undergo a change in physical properties when they absorb heat and undergo a phase transition. Therefore, the storage / heat dissipation device 1 can detect whether or not the temperature around the storage / heat dissipation device 1 has reached the phase transition temperature by detecting the change in the physical properties of the trititanium pentoxide particles. Therefore, the heat storage / heat dissipation device 1 can also be used as a temperature sensor. In this case, for example, the heat storage / heat storage device 1 can also be used in an electronic device such as an electronic device that performs a control operation based on a detection result using the heat storage / heat dissipation device 1. Applicable. Further, since the storage / heat dissipation device 1 absorbs heat at the phase transition temperature, it may be a target for detecting the amount of heat to be absorbed. In this case, it is possible to detect the amount of heat energy that can be absorbed and released when a temperature change occurs with respect to the total amount of heat energy (heat absorption amount) that the titanium oxide-based material can store heat. That is, the heat storage / heat dissipation device 1 can also be used as a heat quantity sensor. The application of the heat storage / heat dissipation device 1 is not limited to the above, and for example, the heat storage / heat storage device 1 may be used as a sheet having a heat storage / heat dissipation function.

A case where the storage / heat storage device 1 functions as, for example, a sensor will be specifically described.

As described above, since the storage / heat dissipation device 1 includes a titanium oxide-based material, a temperature change or a change in heat absorption amount is based on a change in physical properties accompanying a phase transition between solid phases of trititanium pentoxide particles. Can be detected. Therefore, the heat storage / heat dissipation device 1 can be used as a sensor element that functions as a sensor for detecting, for example, temperature or heat absorption. In this case, the sensor element causes, for example, a discontinuous change in the physical properties of the trititanium pentoxide particles due to the phase transition or a phenomenon caused by this change when the temperature of the trititanium pentoxide particles exceeds the phase transition temperature. Can be output.

When the storage / heat dissipation device 1 functions as a sensor element, the output of the sensor element includes electrical conductivity (electrical conductivity), color, magnetism (magnetic susceptibility), and volume change (specific gravity), which are physical properties that change with the phase transition. (Change) or thermal conductivity (thermal conductivity) and the like.

Regarding electrical conductivity, in trititanium pentoxide, which is a titanium oxide-based material, the β phase is a semiconductor, and the λ phase and the α phase are conductors. Therefore, the sensor element can output the change in electrical conductivity. The sensor element has electrical conductivity such as a change in voltage due to a change in electrical conductivity when a constant current is flowing, and a change in current due to a change in electrical conductivity when a constant voltage is applied. You may output the phenomenon that occurs with the change of.

Regarding the color, for example, β-trititanium pentoxide is red or reddish brown, and λ-trititanium pentoxide is black blue or blue. Therefore, the sensor element can output the color change due to the trititanium pentoxide particle phase transition of the titanium oxide-based material.

In terms of magnetism, β-trititanium pentoxide is non-magnetic, and α-trititanium pentoxide and λ-trititanium pentoxide are paramagnetic. Therefore, the sensor element can output the change in magnetism due to the phase transition of the trititanium pentoxide particles of the titanium oxide-based material.

Regarding the thermal conductivity, since the specific heat of the trititanium pentoxide particle of the titanium oxide material changes with the phase transition, for example, the change in thermal conductivity and thermal diffusivity based on the change in the specific heat is output. May be good.

Further, regarding the volume, since the volume change may occur at the time of the phase transition of the trititanium pentoxide particles of the titanium oxide-based material, the change in physical properties based on the volume change or the change in specific gravity may be output.

The output of the sensor element is not limited to the above. Further, the output described above is not limited to the case where the storage / heat storage device 1 functions as a sensor element, and may be the output of the storage / heat storage device 1 itself.

The sensor element includes, for example, a molded product containing a titanium oxide-based material. The molded product may contain the trititanium pentoxide particles described above, and the molded product may contain components other than trititanium pentoxide, if necessary, as long as the intended use of the sensor element is not impaired. .. Examples of components other than trititanium pentoxide include resin components that function as binders. Therefore, the molded product may be produced from a composition prepared by blending a titanium oxide-based material with a resin component or the like. The molded body can have an appropriate shape. For example, a titanium oxide-based material can be molded with a molding machine to obtain a cylindrical molded body, but the present invention is not limited to this. The dimensions of the sensor element may be appropriately adjusted according to the application and the like. The shape of the molded body is also preferably sheet-like. That is, it is also preferable that the storage / heat dissipation device 1 has a sheet shape. The case where the heat storage / heat dissipation device 1 is in the form of a sheet will be described in detail later.

The sensor element may include electrodes that are electrically connected to the molded body. The sensor element includes, for example, two electrodes, and the electrodes and the molded body are laminated so that the molded body is interposed between the two electrodes. When the sensor element includes an electrode, the sensor element can emit an output through the electrode. The sensor element itself does not have an electrode, and the electrode may be electrically connected to the sensor element when an output is obtained from the sensor element.

The electrode is made of, for example, a metal, a conductive oxide, a carbon material, a conductive polymer, or the like. Examples of the metal include Al, Ag, Au, Cu, Pt and the like. Examples of the conductive oxide include indium tin oxide (ITO: Indium Tin Oxide). Examples of the carbon material include graphite and the like. Examples of the conductive polymer include a polythiophene-based polymer, a polyaniline-based polymer, and a polyacetylene-based polymer.

The device for detecting the output of the sensor element is, for example, a device for detecting a change in the electric resistance value, but the device is not limited to this. For example, the device for detecting the output of the sensor element is a specific heat measuring device configured to detect a specific thermal change by an appropriate method, a spectrum measuring device configured to detect a color change, and a magnetic measurement for detecting a magnetic change. It may be a device, a specific gravity measuring device for measuring a change in specific gravity, or the like.

As described above, the heat storage / heat dissipation device 1 according to the present embodiment can be used as a sensor for various purposes capable of responding to external stimuli in the surroundings. That is, the heat storage / heat dissipation device 1 can have a function as a sensor for detecting the temperature. For example, the heat storage / heat dissipation device 1 may be a sensor element alone, or may be a device having a sensor function and other functions.

The application of the storage / heat dissipation device 1 will be described with reference to FIG. 5 with a specific example.

In FIG. 5, the heat storage / heat storage device 1 is formed in a sheet shape. Specifically, the heat storage / dissipation device 1 includes a sheet material 11, a first electrode 12, a second electrode 13, and a detection unit 16. The sheet material 11 contains a titanium oxide-based material containing trititanium pentoxide particles having a median diameter D50 of 3 μm or more. The sheet material 11 may have one or both functions of endothermic and heat dissipation. The first electrode 12 is arranged on the first surface 11a of the sheet material 11. The second electrode 13 is arranged on the second surface 11b on the side opposite to the first surface 11a of the sheet material 11. The first electrode 12 and the second electrode 13 are electrically connected to each other via the sheet material 11, and in FIG. 5, they are a pair of electrodes located on opposite sides of the sheet material 11. The detection unit 16 is electrically connected to the sheet material 11 via the first electrode 12 and the second electrode 13. Therefore, the heat storage / heat dissipation device 1 can detect heat from, for example, a heating element 4 located outside or inside the heat storage / heat storage device 1 with the sheet material 11.

The positions, shapes, and dimensions of the first electrode 12 and the second electrode 13 which are a pair of electrodes are not particularly limited. For example, both the first electrode 12 and the second electrode 13 may be arranged on the same surface of the sheet material 11 (for example, on the first surface 11a). Each of the first electrode 12 and the second electrode 13 may be the same as those described for the electrodes in the sensor element described above.

The detection unit 16 can detect the electrical characteristics of the sheet material 11 by using the first electrode 12 and the second electrode 13. As a result, for example, when the storage / heat dissipation device 1 and the heating element 4 capable of generating heat are thermally connected, the storage / heat dissipation device 1 has the electrical characteristics of the titanium oxide-based material in the sheet material 11 at the detection unit 16. By detecting the change in, it is possible to detect that the temperature has reached the phase transition temperature.

The detection unit 16 may be, for example, an electric resistance detector having a function of detecting electric resistance. In this case, the storage / heat dissipation device 1 can detect, for example, that the trititanium pentoxide in the sheet material 11 has reached the phase transition temperature by receiving the heat generated by the heating element 4, for example.

The heating element 4 is not particularly limited and may be provided around or inside the heat storage / radiation device 1. The heating element 4 may be, for example, a heating component or the like that generates heat by supplying power from an external power source or the like. The heat-generating component is, for example, an electronic component that converts a part of energy given for driving into heat and releases it. The heat-generating component is not particularly limited, but specific examples of the heat-generating component include integrated circuits such as a central processing device (CPU), a power management IC (PMIC), a power amplifier (PA), a transceiver IC, and a voltage regulator (VR). (IC); Light emitting elements such as light emitting diodes (LEDs), incandescent bulbs, semiconductor lasers; Active elements such as field effect transistors (FETs); Passive elements such as coils, capacitors, resistors, etc. At least one selected from the group. including. Specific examples of the heating element 4 include home appliances, lighting fixtures, medical equipment, electric furnaces, switchboards, water heaters, anti-fog devices, anti-freezing devices, and the like.

The detection unit 16 detects changes in physical properties such as thermal conductivity, magnetism, specific gravity, and wavelength characteristics, which may change during a phase transition of trititanium pentoxide in a titanium oxide-based material in the sheet material 11, for example. There may be. In particular, the heat storage / heat dissipation device 1 preferably detects changes in the physical properties of either or both of the electric conductivity and the thermal conductivity of the titanium oxide-based material. The number of detection units 16 in the storage / heat dissipation device 1 is not particularly limited, and the number of detection units 16 may be one or a plurality.

The storage / heat dissipation device 1 is not limited to the above configuration, and may include a member having an appropriate function. For example, the heat storage / heat dissipation device 1 may include a control unit 17 that controls the operation of the heat storage / heat storage device 1 or the heating element 4 based on the result detected by the detection unit 16. When the storage / heat storage device 1 includes the control unit 17, the operation of the storage / heat storage device 1 can be relaxed or stopped even when the storage / heat storage device 1 receives excessive heat from the heating element 4, for example. Further, the heat storage / heat dissipation device 1 may include, for example, a support member (not shown) that supports the sheet material 11, the first electrode 12, and the second electrode 13. The material, dimensions, and shape of the support member are not particularly limited.

Hereinafter, specific examples of the present invention will be presented. However, the present invention is not limited to the examples.

(1) Preparation of titanium oxide-based material Prepare trititanium pentoxide (product number 100097, minimum particle size 0.8 mm, maximum particle size 4.0 mm) manufactured by Merck Co., Ltd. as a raw material, and put it in a zirconia container. Titanium oxide (10 to 20 g) and 150 g of water were added. 450 g of a zirconia ball (ball diameter φ10 mm) was put into a container, the above container was placed on a crushing device, and crushing was performed at a rotation speed of 150 to 200 rpm. As a crushing device, a planetary ball mill (manufactured by Fritsch: model number P-5) was used. The specific conditions of the pulverization treatment in each example are as follows.

In Example 1, 10 g of trititanium pentoxide was treated at a rotation speed of 150 rpm for 120 minutes to obtain trititanium pentoxide particles having the particle size distribution shown in FIG. 4A. FIG. 3A is an SEM image obtained by measuring the trititanium pentoxide particles obtained in Example 1 with an SEM (scanning electron microscope). The median diameter D50 was 3.164 μm.

In Example 2, 20 g of trititanium pentoxide was treated at a rotation speed of 150 rpm for 120 minutes to obtain trititanium pentoxide particles having the particle size distribution shown in FIG. 4B. FIG. 3B is an SEM image obtained by measuring the trititanium pentoxide particles obtained in Example 2 by an SEM (scanning electron microscope). The median diameter D50 was 5.713 μm.

In Example 3, 20 g of trititanium pentoxide was treated at a rotation speed of 150 rpm for 30 minutes to obtain trititanium pentoxide particles having the particle size distribution shown in FIG. 4C. The median diameter D50 was 10.21 μm.

In Example 4, 20 g of trititanium pentoxide was treated at a rotation speed of 150 rpm for 15 minutes to obtain trititanium pentoxide particles having the particle size distribution shown in FIG. 4D. FIG. 3C is an SEM image obtained by measuring the trititanium pentoxide particles obtained in Example 3 with an SEM (scanning electron microscope). The median diameter D50 was 16.49 μm.

In Example 5, 20 g of trititanium pentoxide was treated at a rotation speed of 200 rpm for 5 minutes to obtain trititanium pentoxide particles having the particle size distribution shown in FIG. 4E. The median diameter D50 was 21.39 μm.

The trititanium pentoxide particles of Comparative Example 1 were obtained by treating trititanium pentoxide (3 g) of Example 1 at a rotation speed of 200 rpm for 120 minutes. The trititanium pentoxide particles of Comparative Example 1 had a particle size distribution shown in FIG. 4F, and the median diameter D50 was 1.572 μm.

Further, in Example 6, the size of the particles as a sample used for the measurement by the DSC device was measured without performing the pulverization treatment of Examples 1 to 5 (see Table 1). Note that FIG. 3D is an SEM image obtained by measuring the trititanium pentoxide particles of Example 6 by SEM (scanning electron microscope).

(2) Evaluation of Titanium Oxide Material The phase transition temperature and heat absorption amount of the trititanium pentoxide particles of each Example and Reference Example obtained in (1) were measured by differential scanning calorimetry. In the measurement, a DSC device (model number DSC 220c manufactured by Seiko Denshi Kogyo Co., Ltd.) was used, Air gas was flowed at 100 mL / min, and the temperature was raised from room temperature to 300 ° C at a heating rate of 10 ° C./min. After reaching 300 ° C., the temperature was lowered (cooled) at 10 ° C./min to room temperature. After reaching room temperature, the temperature was raised again from room temperature to 300 ° C. at a rate of 10 ° C./min. The phase transition temperature and heat absorption amount obtained from the results are shown in Table 1 below.

FIG. 1 is a graph showing the results of DSC measurement of trititanium pentoxide particles of Example 4, the broken line shows the thermal behavior due to the first temperature rise and fall, and the solid line shows the second temperature rise and temperature decrease. It shows the thermal behavior due to the temperature drop.

FIG. 2 is a graph plotting the amount of heat absorbed calculated from the results obtained by DSC measurement with respect to the median diameter D50 of the trititanium pentoxide particles of each Example and Reference Example. The plot indicated by the white circle is the amount of heat absorbed during the first temperature rise, and the plot indicated by the black square is the amount of heat absorbed during the second temperature rise.

Table 1 shows the relationship between the median diameter D50 of the trititanium pentoxide particles of each example and the reference example, the amount of heat absorbed, and the phase transition temperature.

The amount of heat absorbed by the trititanium pentoxide particles of Examples 1 to 3 was small due to the first temperature rise, but the amount of heat absorbed by the second temperature rise was significantly increased as compared with the first temperature rise. In Examples 4 and 5, the amount of heat absorbed by the first temperature rise was 20 J / g or more, and the amount of heat absorbed by the second temperature rise was further increased. Further, Example 5 showed the same behavior as the thermal behavior of Example 4 shown in FIG.

In Comparative Example 1, no endotherm due to the first temperature rise was observed. In addition, although heat absorption was observed by the second temperature rise, the amount of heat absorption was lower than that of any of the examples.

As a result, when the median diameter D50 of the trititanium pentoxide particles is 10 μm or less (Examples 1 to 3), the amount of heat absorbed in the first time is very small (about 0 J / g), whereas the amount of heat absorbed in the second time is very small. It was suggested that the calorific value would be 20 J / g or more. Further, in Examples 1 to 5, it was suggested that as the median diameter D50 increased, the second phase transition temperature increased more than the first phase transition temperature. Further, in Example 6, the phase transition temperature and the heat absorption amount did not change between the first time and the second time due to the temperature rise, but the heat absorption amount was 20 J / g or more in both the first time and the second time. Further, in Comparative Example 1, since the heat absorption amount was 0 J / g at the first temperature rise, the phase transition temperature could not be obtained.

[Summary]
As is clear from the above, the titanium oxide-based material of the first aspect of the present disclosure contains trititanium pentoxide particles. Trititanium pentoxide has a phase transition temperature at which a phase transition occurs between solid phases and has a median diameter D50 of 3 μm or more.

According to the first aspect, the titanium oxide-based material can reversibly undergo a phase transition by heating and cooling, and can have an excellent heat absorption amount. As a result, the titanium oxide-based material contains trititanium pentoxide particles and tends to exhibit good endothermic properties.

In the first aspect, the titanium oxide-based material of the second aspect contains the β phase of the trititanium pentoxide particles, and the β phase is heated to the α phase at the first endothermic phase transition temperature. It transfers and absorbs the first endothermic amount. The α phase undergoes a phase transition to the β phase after being cooled, and then undergoes a phase transition to the α phase at the second endothermic phase transition temperature when heated again, and absorbs the second endothermic amount. The trititanium pentoxide particles have a second heat absorption amount larger than that of the first heat absorption amount.

According to the second aspect, the titanium oxide-based material can reversibly undergo a phase transition by heating and cooling, and can have an excellent heat absorption amount.

The titanium oxide-based material of the third aspect has a second heat absorption amount of 20 J / g or more in the second aspect.

According to the third aspect, the titanium oxide-based material can be suitably used as a heat storage and heat dissipation material which can reversibly undergo a phase transition by heating and cooling and has an excellent heat absorption amount.

In the second or third aspect, the titanium oxide-based material of the fourth aspect has a lower endothermic phase transition temperature than the first endothermic phase transition temperature.

According to the fourth aspect, the titanium oxide-based material can absorb heat even at a temperature lower than that of the conventional trititanium pentoxide, and can reversibly undergo a phase transition by heating and cooling.
it can.

In any one of the second to fourth aspects, the titanium oxide-based material of the fifth aspect has a second endothermic phase transition temperature of 191 ° C. or lower.

According to the fifth aspect, heat reaching a relatively high temperature such as 200 ° C. or higher can be absorbed from a lower temperature.

The titanium oxide-based material of the sixth aspect has a first heat absorption amount of 20 J / g or more in any one of the second to fifth aspects.

According to the sixth aspect, the titanium oxide-based material can have particularly excellent endothermic properties.

The titanium oxide-based material of the seventh aspect has a trititanium pentoxide particle median diameter D50 of 15 μm or more in any one of the first to sixth aspects.

According to the seventh aspect, when the median diameter D50 of the trititanium pentoxide particles is 15 μm or more, the titanium oxide-based material is higher even without heating at a temperature exceeding the first phase transition temperature. The amount of heat absorption can be achieved.

The titanium oxide-based material according to the eighth aspect has a trititanium pentoxide particle median diameter D50 of 3 μm or more and less than 15 μm in any one of the first to sixth aspects.

According to the eighth aspect, when the median diameter D50 of the trititanium pentoxide particles is 3 μm or more, the trititanium pentoxide can have absorption and heat dissipation characteristics as described above. In particular, when the median diameter D50 of the trititanium pentoxide particles is less than 15 μm, the thermal history of the phase transition temperature can be stored when heating at a temperature exceeding the first phase transition temperature. On the other hand, in this case, the trititanium pentoxide can have a high amount of heat absorption in the second and subsequent heatings by passing heat dissipation.

The heat storage / heat dissipation device (1) of the ninth aspect includes a titanium oxide-based material according to any one of the first to eighth aspects.

In the ninth aspect, it is possible to output a discontinuous change in the physical properties of the trititanium pentoxide particles of the titanium oxide-based material due to the phase transition, or a phenomenon caused by this change.

In the ninth aspect, the heat storage / heat dissipation device (1) of the tenth aspect absorbs heat or dissipates heat at the phase transition temperature of the titanium oxide-based material.

According to the tenth aspect, the storage / heat dissipation device (1) can detect that the temperature of the detection target exceeds the phase transition temperature, and can store the thermal history that the temperature exceeds the phase transition temperature.

The heat storage / heat dissipation device (1) of the eleventh aspect detects a change in the physical properties of either one or both of the electric conductivity and the thermal conductivity of the titanium oxide-based material in the ninth or tenth aspect.

In the eleventh aspect, it is possible to output a discontinuous change in the physical properties of the trititanium pentoxide particles in the titanium oxide-based material accompanying the phase transition, or a phenomenon caused by this change. In addition, it can be used as a sensor for various purposes capable of responding to external stimuli around it.

The method for producing a titanium oxide-based material containing trititanium pentoxide particles according to a twelfth aspect includes a step of pulverizing trititanium pentoxide.

According to the twelfth aspect, trititanium pentoxide particles having a controlled particle size can be obtained.

1 Storage and heat dissipation device

Claims (12)

A titanium oxide-based material containing trititanium pentoxide particles.
The trititanium pentoxide particles have a phase transition temperature at which a phase transition occurs between solid phases and have a median diameter D50 of 3 μm or more.
Titanium oxide material. The trititanium pentoxide particles contain a β phase and contain a β phase.
When the β phase is heated, the phase transitions to the α phase at the first endothermic phase transition temperature, and the first endothermic amount is absorbed.
The α phase undergoes a phase transition to the β phase after being cooled, and then undergoes a phase transition to the α phase at the second endothermic phase transition temperature when heated again, and absorbs the second endothermic amount.
The second heat absorption amount is larger than the first heat absorption amount.
The titanium oxide-based material according to claim 1. The second heat absorption amount is 20 J / g or more.
The titanium oxide-based material according to claim 2. The second endothermic phase transition temperature is lower than the first endothermic phase transition temperature.
The titanium oxide-based material according to claim 2 or 3. The second endothermic phase transition temperature is 191 ° C. or lower.
The titanium oxide-based material according to any one of claims 2 to 4. The first heat absorption amount is 20 J / g or more.
The titanium oxide-based material according to any one of claims 2 to 5. The median diameter D50 of the trititanium pentoxide particles is 15 μm or more.
The titanium oxide-based material according to any one of claims 1 to 6. The median diameter D50 of the trititanium pentoxide particles is 3 μm or more and less than 15 μm.
The titanium oxide-based material according to any one of claims 1 to 6. The titanium oxide-based material according to any one of claims 1 to 8 is provided.
Storage and heat dissipation device. Endothermic or heat dissipates at the phase transition temperature of the titanium oxide material.
The storage and heat storage device according to claim 9. Detects the physical properties of either or both of the electrical conductivity and thermal conductivity generated by heating or cooling.
The storage and heat storage device according to claim 9 or 10. A method for producing a titanium oxide-based material containing trititanium pentoxide particles.
Including the step of crushing the massive trititanium pentoxide,
A method for manufacturing a titanium oxide-based material.