JP7180316B2 - Heat storage material and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat storage material and a manufacturing method thereof.

In recent years, for the purpose of more efficient heat utilization, there has been a demand for a technique for storing the generated thermal energy and generating heat according to the situation. As heat storage materials, hydrated salts such as sodium sulfate decahydrate, paraffin, linear aliphatic amines, and the like are known (Patent Document 1). However, since this latent heat storage material undergoes liquid-solid phase transition, it has problems such as volume fluctuation and thermal resistance, and needs to be dealt with by means of a container, microencapsulation, or the like.

In addition to the latent heat storage described above, there are also known latent heat storage systems that utilize solid-solid phase change. There is no need to consider wettability with the material. For example, Patent Document 2 describes a thermal energy storage material containing a heat storage material such as 2-amino-2-methyl-1,3-propanediol and a resin. However, 2-amino-2-methyl-1,3-propanediol is highly hydrophilic, and the method of Patent Document 2 results in a high water content, resulting in an insufficient calorific value.

JP 2018-145219 A JP-A-61-233904

An object of the present invention is to provide a heat storage and heat release material that has a high heat storage amount and heat generation amount, has excellent heat storage and heat release properties, and is excellent in resistance to repeated heat storage and release.

The present invention relates to the following [1] to [4].

[1] A heat storage/radiation material containing 2-amino-2-methyl-1,3-propanediol, wherein the moisture content of the heat storage/radiation material is 5% by mass or less, and the material is heated from -50°C to 70°C. A heat storage and heat release material having a calorific value of 50 J/g or more under hot conditions.

[2] The heat storage material according to [1], wherein the 2-amino-2-methyl-1,3-propanediol has an average primary particle size of 0.2 to 20 μm.

[3] A method for producing a heat storage material containing 2-amino-2-methyl-1,3-propanediol, comprising a mixture containing 2-amino-2-methyl-1,3-propanediol and an organic solvent A method for producing a heat storage material, characterized by removing the organic solvent after dispersing the liquid with a media dispersing machine.

[4] The method for producing a heat storage material according to [3], wherein the organic solvent has a solubility of 2-amino-2-methyl-1,3-propanediol at 25°C of 2% by mass or less.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a heat storage and release material that has high heat storage and heat generation, excellent heat storage and heat release properties, and excellent resistance to repeated heat storage and release.

<Heat storage material>
The heat storage and heat storage material of the present invention contains 2-amino-2-methyl-1,3-propanediol, has a water content of 5% by mass or less, and is heated from -50°C to 70°C. It is characterized by having a calorific value of 50 J/g or more under certain conditions. The calorific value is preferably 100 J/g or more. When the water content of the heat and heat storage material is 5% by mass or less, the 2-amino-2-methyl-1,3-propanediol contained in the heat and heat storage material is in a crystalline state, exhibiting good heat and heat storage properties.
The present invention will be described in detail below.

<2-amino-2-methyl-1,3-propanediol>
2-Amino-2-methyl-1,3-propanediol is a material that exhibits heat storage properties due to a phase change due to a solid-solid phase transition. It absorbs heat and maintains the endothermic state even if the temperature is lowered to around -50°C in the endothermic state. After that, heat is generated by heating from around -50°C to around 0°C to 70°C, physical stimulation, introduction of seed crystals, and the like.
More specifically, it absorbs heat in the process of increasing the temperature from 25°C to 95°C, does not generate heat when the temperature is decreased from 95°C to -50°C, but maintains the endothermic state, and generates heat when the temperature is increased from this state to 70°C. Even if it is repeated, heat absorption and heat generation occur again. Specifically, from the state where heat is generated when the temperature is raised to 70° C., heat is absorbed again in the process of raising the temperature to 95° C., and when the temperature is lowered from 95° C. to −50° C., the endothermic state is maintained without generating heat. to 70°C.

A general latent heat storage material absorbs heat when the temperature rises and releases heat when the temperature drops. In addition, 2-amino-2-methyl-1,3-propanediol has the property of absorbing heat when the temperature rises but not releasing heat when the temperature drops. Therefore, unlike general latent heat storage materials, there is no need to maintain heat retention above the phase change temperature, and unused heat can be utilized in various ways.

In addition, 2-amino-2-methyl-1,3-propanediol is very hydrophilic, so when the amount of water in the vicinity increases, the water content increases and becomes a dissolved state, and the heat storage property decreases significantly. Resulting in. Therefore, it is very important to set the water content of the heat storage and heat storage material to 5% by mass or less, that is, to lower the water content of 2-amino-2-methyl-1,3-propanediol. The moisture content of the heat storage and heat storage material is preferably 3% by mass or less, particularly preferably 1% by mass or less, from the viewpoint of heat storage property and heat resistance to repeated heat storage.

The heat storage material of the present invention may contain a heat storage material other than 2-amino-2-methyl-1,3-propanediol as long as the heat storage property is not impaired. Examples include paraffin wax and titanium oxide. and inorganic oxides such as vanadium oxide, and polyhydric alcohols such as 2-methyl-2-nitro-1,3-propanediol.
From the viewpoint of heat storage property, the ratio of 2-amino-2-methyl-1,3-propanediol in the total heat storage material is preferably 50% by mass or more. From the viewpoint of heat storage property, the content of 2-amino-2-methyl-1,3-propanediol is more preferably 50 to 100% by mass based on the total solid content in the heat storage material. 80 to 100% by mass.

Also, the average primary particle size of 2-amino-2-methyl-1,3-propanediol is preferably 0.2 to 20 μm. It is more preferably 0.5 μm to 10 μm, particularly preferably 1 μm to 5 μm. A particle size of 0.2 μm or more is preferable because it has a particle shape unlike a completely dissolved state, thereby increasing the amount of stored heat and heat, and further improving resistance to repeated heat storage and heat release. In addition, when the particle size is 20 μm or less, an appropriate particle state is obtained, and the amount of heat and heat storage increases, and the resistance to repeated heat and heat storage is improved, which is preferable.

The method for adjusting the average primary particle size of 2-amino-2-methyl-1,3-propanediol to 0.2 to 20 μm is not particularly limited, but the above particle size can be easily obtained by performing a dispersion treatment. be able to. For example, a method of dispersing a mixture containing 2-amino-2-methyl-1,3-propanediol and an organic solvent with a media disperser and then removing the organic solvent is preferably used.

<Organic solvent>
The method for producing a heat storage material of the present invention comprises dispersing a mixed liquid containing 2-amino-2-methyl-1,3-propanediol and an organic solvent with a media dispersing machine, and then removing the organic solvent. Characterized by
As the organic solvent, a medium that is liquid at 25°C is preferable. Specifically, ester solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, and propylene glycol monomethyl ether acetate; alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; and benzene. , Toluene, xylene and other aromatic solvents, acetone, methyl ethyl ketone, diisopropyl ketone, cyclohexanone and other ketone solvents, and n-octane and other hydrocarbon solvents can be used alone or in combination.

When 2-amino-2-methyl-1,3-propanediol dissolves in an organic solvent, the dispersing effect of 2-amino-2-methyl-1,3-propanediol decreases. -2-Methyl-1,3-propanediol with low solubility is preferred. Among them, the solubility of 2-amino-2-methyl-1,3-propanediol at 25° C. is preferably 10% or less, more preferably 2% or less, particularly preferably 1% or less. is a solvent. A preferable example of the organic solvent having a solubility of 1% or less is methyl ethyl ketone.

There are no particular restrictions on the disperser, and examples include kneaders, attritors, ball mills, sand mills using glass beads or zirconia beads, scandex, Eiger mills, paint conditioners, media dispersers such as paint shakers, and colloid mills. can.

<Other ingredients>
The heat storage material of the present invention can further contain pigment dispersants, pigment derivatives, surfactants, flame retardants, fillers, and various other additives.
A pigment derivative is obtained by introducing a specific substituent into an organic pigment residue described in the Color Index. Examples of flame retardants include aluminum hydroxide, magnesium hydroxide, and phosphoric acid compounds. Additives include, for example, a coupling agent for enhancing adhesion to a substrate, an ion scavenger/antioxidant for enhancing reliability during moisture absorption and at high temperatures, and a leveling agent.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. Parts and % in the present invention represent parts by mass and % by mass unless otherwise specified.

<Moisture content of heat storage material>
The moisture content of the heat-storage layer was obtained by the Karl Fischer titration method (moisture vaporization method) of JIS K0068:2001 (method for measuring moisture content of chemical products). Specifically, 50.0 mg of the heat storage material is sampled using an electronic balance, and set in a Karl Fischer moisture meter (coulometric method) MKC-610 manufactured by Kyoto Electronics Industry Co., Ltd. and a moisture vaporizer ADP-611 to measure the moisture content. The moisture content was converted into a ratio per unit mass of the composition to determine the moisture content of the heat storage/radiation layer. The measurement was carried out using ChemAqua anolyte AKE and ChemAqua catholyte CGE manufactured by Kyoto Electronics Industry Co., Ltd. as the anolyte and catholyte, respectively, at a measurement temperature of 140° C., using nitrogen as the carrier gas, and at a flow rate of 200 mL/ I went as min.

<Production of heat storage material>
[Example 1]
(Storage and heat release material 1)
2-Amino-2-methyl-1,3-propanediol with a water content of 10% was dried at a temperature of 60° C. for 48 hours to obtain a heat-storage material 1 with a water content of 0.2%.

[Example 2]
(Storage and heat release material 2)
A heat and storage material 2 having a moisture content of 2.3% was obtained in the same manner as for the heat and heat storage material 1, except that the drying time was changed to 24 hours.

[Example 3]
(Storage and heat release material 3)
A heat and storage material 3 having a moisture content of 4.5% was obtained in the same manner as for the heat and heat storage material 1, except that the drying time was changed to 17 hours.

[Example 4]
(Storage and heat release material 4)
10.0 parts of heat-storage material 1 having a water content of 0.2%, 30.0 parts of methyl ethyl ketone, and 20 parts of glass beads with a diameter of 3 mm were placed in a container, stirred and mixed, and dispersed with a paint shaker for 1.5 hours. After that, the obtained dispersion was dried at a temperature of 50° C. for 2 hours to remove the organic solvent, thereby obtaining a heat storage/radiation material 4a. The heat storage/radiation material 4a thus obtained was allowed to stand at a temperature of 25° C. and a humidity of 80% RH for 2 hours to obtain a heat storage/radiation material 4b having a moisture content of 10%. Next, heat storage material 4b was dried at a temperature of 60° C. for 48 hours to obtain heat storage material 4 with a moisture content of 0.2%. The solubility of 2-amino-2-methyl-1,3-propanediol in methyl ethyl ketone at 25° C. is 1% or less.

[Example 5]
(Storage and heat release material 5)
A heat and storage material 5 having a moisture content of 2.4% was obtained in the same manner as for the heat and heat storage material 4, except that the drying time in the 48-hour drying process at a temperature of 60°C was changed to 24 hours.

[Example 6]
(Storage and heat release material 6)
A heat-storage material 6 having a moisture content of 4.5% was obtained in the same manner as the heat-storage material 4, except that the drying time in the 48-hour drying process at a temperature of 60°C was changed to 17 hours.

[Example 7]
(Storage and heat release material 7)
Heat storage material 7 having a water content of 0.2% was obtained in the same manner as heat storage material 4, except that the dispersion time in the paint shaker was 3.5 hours.

[Example 8]
(Storage and heat release material 8)
Heat storage material 8 having a water content of 0.2% was obtained in the same manner as heat storage material 4, except that the dispersion time in the paint shaker was 5.5 hours.

[Comparative Example 1]
(Storage and heat release material 101)
2-Amino-2-methyl-1,3-propanediol having a moisture content of 10% was used as the heat-storage material 101 .

[Comparative Example 2]
(Storage and heat release material 102)
2-Methyl-2-nitro-1,3-propanediol with a water content of 0.1% was used as the heat-storage material 102 .

<Evaluation of heat storage material>
The following evaluations were carried out on the obtained heat storage/radiation material. Table 1 shows the results.

[Average primary particle size]
The heat-storage material was observed with a scanning electron microscope (SEM), 10 particles of the heat-storage material were arbitrarily selected, and the primary particle diameters were visually measured, and the average value was taken as the average primary particle diameter.

[Heat generation amount under heating conditions from -50°C to 70°C, repeated resistance to storage and heat release]
Using Mettler-Toledo's "DSC-1", about 5 mg of the obtained heat storage and heat storage material is weighed in an aluminum standard container, the following 4-cycle test is performed, and the endothermic amount is determined from the differential heat curve of the reversible component. and the calorific value were calculated.
(first cycle)
The temperature was raised from 25°C to 95°C at a rate of 10°C/min. After maintaining the temperature at 95° C. for 5 minutes, the temperature was lowered from 95° C. to −50° C. at a rate of 10° C./min, and the temperature was maintained at −50° C. for 5 minutes. Next, the temperature was raised from -50°C to 70°C at a rate of 10°C/min, and the amount of heat generated during that time was calculated.
(second cycle)
After the end of the first cycle, the temperature was raised to 95°C at a rate of 10°C/min, and the amount of heat absorbed during that time was calculated. After maintaining the temperature at 95° C. for 5 minutes, the temperature was lowered from 95° C. to −50° C. at a rate of 10° C./min, and the temperature was maintained at −50° C. for 5 minutes. Next, the temperature was raised from -50°C to 70°C at a rate of 10°C/min, and the amount of heat generated during that time was calculated.
(3rd cycle)
The temperature was raised, lowered, and raised in the same manner as in the second cycle, and the amount of heat absorbed and the amount of heat generated were calculated.
(4th cycle)
The temperature was raised, lowered, and raised in the same manner as in the second cycle, and the amount of heat absorbed and the amount of heat generated were calculated.

For the calorific value under heating conditions from -50°C to 70°C, the minimum calorific value among the calculated calorific values was used, except when the calorific value was 0 J/g. For example, in the case of Example 1, the calorific value under heating conditions from -50°C to 70°C is 131 J/g.

Abbreviations in Table 1 are shown.
AMP: 2-amino-2-methyl-1,3-propanediol

From the evaluation results in Table 1, it was confirmed that all of the examples using heat and energy storage materials with a water content of 5% by mass or less have heat and energy storage properties and are excellent in repeated resistance to heat and heat storage properties. Further, when the water content was 1% by mass or less, a more excellent heat storage amount was exhibited (Examples 1 to 3, 4 to 6). On the other hand, Comparative Example 1, which has a high moisture content, did not exhibit heat storage properties.

Furthermore, in Examples 4 to 6, the average primary particle size is reduced through the dispersion step, so compared to Examples 1 to 3 that have not undergone the dispersion step, even when the water content is the same, the heat storage amount is increased. was increasing.

In Examples 7 and 8, the dispersion time was changed, and Example 7 showed performance equal to or better than Example 4. On the other hand, in Example 8, an increase in the average primary particle diameter presumed to be due to fusion of primary particles due to overdispersion was confirmed, but good heat storage properties and resistance to repeated heat storage and heat release were observed.

Since Comparative Example 102 did not use 2-amino-2-methyl-1,3-propanediol, it did not develop heat storage properties regardless of the water content.

Claims (3)

A heat-storage material containing 2-amino-2-methyl-1,3-propanediol,
The water content of the heat storage and heat release material is 5% by mass or less, the calorific value under heating conditions from −50° C. to 70° C. is 50 J/g or more, and the 2-amino-2-methyl-1, A heat-storage material in which 3-propanediol has an average primary particle size of 0.2 to 20 μm . A method for producing a heat storage material containing 2-amino-2-methyl-1,3-propanediol,
1. A method for producing a heat storage material, comprising dispersing a mixed liquid containing 2-amino-2-methyl-1,3-propanediol and an organic solvent with a media dispersing machine, and then removing the organic solvent. 3. The method for producing a heat storage material according to claim 2 , wherein the organic solvent has a solubility of 2-amino-2-methyl-1,3-propanediol at 25° C. of 2% by mass or less.