Activated carbon integrated with latent heat storage material and its manufacturing method

Abstract

This latent heat storage material-integrated active carbon contains an active carbon and a latent heat storage material having a microcapsule in which a phase-transition material, which absorbs and releases latent heat according to temperature, is encapsulated, wherein: in the latent heat storage material, the surface of the microcapsule is coated with an organic binder-containing layer including a thermosetting organic binder A; and the surface of the latent heat storage material is coated with an active carbon-containing layer. The latent heat storage material-integrated active carbon is an adsorbent which can prevent a heat transfer loss in voids between particles by integrating the latent heat storage material and the active carbon while suppressing damage to the latent heat storage material compared to the case of simply mixing a latent heat storage material and active carbon pellets, and which can maintain a high level of adsorption / desorption performance and durability by effectively controlling adsorption heat.

Description

[Technical Field]

[0001] The present invention relates to a latent heat storage material-integrated activated carbon and a method for producing the same. [Background technology]

[0002] As regulations on the emission concentration of harmful air pollutants become stricter, the demand for organic solvent-containing gas treatment equipment is increasing. In particular, organic solvent recovery systems that liquefy and recover organic solvents have the advantage of emitting less carbon dioxide than combustion systems that burn organic solvents to render them harmless, and the recovered organic solvents can be reused.

[0003] The organic solvent recovery system carries out an adsorption process in which an adsorbent adsorbs and removes organic solvents from the gas being treated, and a desorption process in which an inert gas such as heated air desorbs the organic solvent adsorbed on the adsorbent, and is configured by providing a switching means for alternately performing the adsorption process and the desorption process or a means for continuously performing the processes.

[0004] Regulations on fuel evaporative emissions are in place in each country and region, and these regulations are becoming stricter in response to the worsening air pollution problem seen in recent years.Exhaust gases emitted into the atmosphere by automobiles, which are one source of air pollutants, include exhaust gases from burning fuel in the engine, dust kicked up by tires while driving, and evaporative gases generated from the fuel loaded in the automobile and solvents used in automobile materials.

[0005] The canister, an automotive part, temporarily adsorbs (captures) gasoline vapor that evaporates inside the fuel tank onto activated carbon, preventing it from being emitted outside the vehicle. The vapor temporarily adsorbed (captured) onto the activated carbon is purged (scavenged) using the engine's intake manifold negative pressure while driving, and is then combusted by the engine, allowing for repeated performance maintenance.

[0006] As described above, there are a variety of applications in which high-quality adsorption and desorption performance is required of adsorbents. However, since adsorbents themselves have the property that their adsorption capacity increases at lower temperatures and their desorption capacity increases at higher temperatures, temperature is one of the important factors when high-quality products are required.

[0007] Conventionally, the heat that enters and leaves the adsorbent when various gases, liquids, vapors, etc. are adsorbed and desorbed onto the adsorbent can be controlled by flowing a medium such as water from the outside, or by mixing a substance with a high heat capacity by inserting a substance with high thermal conductivity, but this makes the equipment heavier and larger.

[0008] Patent Documents 1 and 2 propose a latent heat storage type adsorbent for canisters, which includes an adsorbent that adsorbs evaporated fuel and a latent heat storage material in which a phase change substance that absorbs and releases latent heat depending on the temperature is microencapsulated. This adsorbent has a significantly better adsorption and desorption performance for evaporated fuel than conventional adsorbents, due to temperature control during adsorption and desorption, and therefore has the advantage of enabling the provision of small, high-performance adsorption towers and canisters. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-179303 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-068693 Summary of the Invention [Problem to be solved by the invention]

[0010] Durability against solvent vapors is important for maintaining high levels of adsorption and desorption performance over long periods of time. During the manufacturing process of integrating latent heat storage materials with activated carbon, physical damage is caused to the surface of the latent heat storage material. When exposed to VOC vapors, the latent heat substance in the microcapsules that make up the latent heat storage material leaks out, reducing the heat capacity of the latent heat storage material and blocking the pores in the activated carbon, preventing the original performance of the adsorbent from being achieved.

[0011] Therefore, in view of the above drawbacks, the object of the present invention is to provide an adsorbent that integrates a latent heat storage material and activated carbon while suppressing damage to the latent heat storage material, that can prevent heat transfer loss in the intergranular voids more effectively than when the latent heat storage material and activated carbon pellets are simply mixed, and that can maintain high levels of adsorption / desorption performance and durability by effectively controlling the heat of adsorption, etc. [Means for solving the problem]

[0012] As a result of intensive research to solve the above problems, the present inventors have found that an adsorbent capable of maintaining high levels of adsorption / desorption performance and durability can be obtained by coating the surface of microcapsules encapsulating a phase-change material with an organic binder-containing layer containing a thermosetting organic binder A, and further coating the surface with an activated carbon-containing layer containing activated carbon. Based on this finding, the present inventors have conducted further research and completed the present invention. That is, the present invention includes the following configurations.

[0013] Item 1. Phase change material that absorbs and releases latent heat depending on temperature A latent heat storage material-integrated activated carbon containing a latent heat storage material having microcapsules encapsulating a substance, and activated carbon, The latent heat storage material has a surface of the microcapsules coated with an organic binder-containing layer containing a thermosetting organic binder A, and The surface of the latent heat storage material is coated with an activated carbon-containing layer containing activated carbon.

[0014] Item 2. The activated carbon integrated with a latent heat storage material according to Item 1, wherein the microcapsules have an average particle size of 0.1 to 500 μm.

[0015] Item 3. The activated carbon integrated with a latent heat storage material according to Item 1 or 2, wherein the activated carbon has an average particle size of 1 μm to 10 mm.

[0016] Item 4. The latent heat storage material-integrated activated carbon according to any one of Items 1 to 3, wherein the activated carbon-containing layer further contains an organic binder B.

[0017] Item 5. The latent heat storage material-integrated activated carbon according to any one of Items 1 to 4, wherein the pH of an aqueous suspension of the activated carbon-containing layer is 4.5 or higher, as measured in accordance with JIS K 1474 (2014).

[0018] Item 6. The activated carbon integrated with a latent heat storage material according to any one of Items 1 to 5, wherein the average cross-sectional diameter of the latent heat storage material is 0.75 to 1.80 mm.

[0019] Item 7. The latent heat storage material-integrated activated carbon according to any one of Items 1 to 6, wherein the content of the latent heat storage material is 7 to 30 mass % relative to 100 mass % of the total amount of the latent heat storage material-integrated activated carbon.

[0020] Item 8. The activated carbon integrated with a latent heat storage material according to any one of Items 1 to 7, having a calorific value of 10 to 100 J / g.

[0021] Item 9. The activated carbon integrated with a latent heat storage material according to any one of Items 1 to 8, which has an ASTM hardness of 45% or more.

[0022] Item 10. A method for producing a latent heat storage material-integrated activated carbon according to any one of items 1 to 9, (1) A step of mixing the microcapsules with the thermosetting organic binder A (2) a step of coating the microcapsule composition obtained in step (1) with the thermosetting organic binder A and heat-treating the coated microcapsule composition to obtain the latent heat storage material; (3) A step of mixing the latent heat storage material obtained in step (2) with a composition containing the activated carbon and granulating the mixture. A manufacturing method comprising:

[0023] Item 11. The manufacturing method according to Item 10, wherein the step (1) is a step of mixing the microcapsules and the thermosetting organic binder A, followed by extrusion granulation and subsequent granulation.

[0024] Item 12. The method according to Item 10 or 11, wherein in the step (3), the composition containing the activated carbon further contains the organic binder B.

[0025] Item 13. The method according to any one of Items 10 to 12, wherein in step (3), the composition containing activated carbon further contains a pH adjuster.

[0026] Item 14. A canister for an automobile, comprising the activated carbon integrated with a latent heat storage material according to any one of items 1 to 9.

[0027] Item 15. A canister for an automobile connected to a sealed gasoline tank, comprising the activated carbon integrated with a latent heat storage material according to any one of items 1 to 9. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide activated carbon integrated with a latent heat storage material, which can maintain high levels of adsorption / desorption performance and durability. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is an SEM image of the latent heat storage material in the latent heat storage material-integrated activated carbon coated with a thermosetting organic binder (Example 4) after Test Example 1 was carried out. [Figure 2] 1 is an SEM image of a latent heat storage material in a latent heat storage material-integrated activated carbon (Comparative Example 3) that is not coated with a thermosetting organic binder after Test Example 1 has been carried out. DETAILED DESCRIPTION OF THE INVENTION

[0030] In this specification, the term "containing" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of." Furthermore, in this specification, when a numerical range is expressed as "A to B," it means A or more and B or less.

[0031] 1. Activated carbon integrated with latent heat storage material The activated carbon integrated with a latent heat storage material of the present invention is a latent heat storage material integrated with a latent heat storage material containing a microcapsule encapsulating a phase change substance that absorbs and releases latent heat depending on the temperature, and activated carbon, in which the surface of the microcapsules of the latent heat storage material is coated with an organic binder-containing layer containing a thermosetting organic binder A, and the surface of the latent heat storage material is coated with an activated carbon-containing layer containing activated carbon.

[0032] Activated carbon integrated with latent heat storage material having such a configuration can be manufactured without physically damaging the latent heat storage material, and therefore when exposed to a solvent, the elution of inclusions from the latent heat storage material is suppressed, making it stable over the long term.In addition, its structure is such that activated carbon is coated on the surface of one latent heat storage material, and the temperature rise due to the heat of adsorption can be efficiently suppressed by the latent heat storage material, thereby demonstrating high solvent adsorption and desorption performance.

[0033] (1-1) Microcapsules The phase-change substance encapsulated in the microcapsules is not particularly limited as long as it is a compound that can absorb and release latent heat as it undergoes a phase change. An example of a phase change is a solid-liquid phase change. The temperature at which the phase-change substance undergoes a phase change (e.g., melting point, freezing point, etc.) can be appropriately selected depending on the application of the canister, but is usually about 0 to 50°C.

[0034] Preferred compounds for such phase-change materials include, for example, linear aliphatic hydrocarbons such as tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, and docosane; natural wax; petroleum wax; hydrates of inorganic compounds such as LiNO3·3H2O, Na2SO4·10H2O, and Na2HPO4·12H2O; fatty acids such as capric acid and lauric acid; higher alcohols having 12 to 15 carbon atoms; and ester compounds such as methyl palmitate and methyl stearate. Phase-change materials can be used alone, or two or more can be combined to adjust the melting point. When two or more phase-change materials are used in combination, a combination in which the difference in the temperatures at which the phase changes occur is approximately 0 to 15°C is preferred.

[0035] In some cases, in order to prevent the phase change material from being supercooled, a compound having a melting point higher than that of the phase change material may be contained.

[0036] Specific examples of the high-melting point compound include aromatic compounds, esters, carboxylic acids, alcohols, amides, etc. The high-melting point compounds may be used alone or in combination of two or more.

[0037] Examples of aromatic compounds include halogen-substituted benzenes, naphthalene, etc. Examples of halogen-substituted benzenes include dihalogenated benzenes such as dibromobenzene and dichlorobenzene.

[0038] Examples of esters include fatty acid esters of monoalcohols such as methyl eicosanoic acid; fatty acid esters of glycerin such as linoleic acid glyceride; and the like.

[0039] Examples of carboxylic acids include aliphatic carboxylic acids such as myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, eicosanoic acid, heneicosanoic acid, and behenic acid; and aromatic carboxylic acids such as benzoic acid.

[0040] Examples of alcohols include monoalcohols having 16 to 30 carbon atoms, such as cetyl alcohol, heptadecanol, stearyl alcohol, nonadecanol, and eicosanol.

[0041] Examples of amides include fatty acid amides such as eicosanoic acid amide, nonadecylic acid amide, stearic acid amide, and oleic acid amide.

[0042] When a high-melting point compound is contained, its content is preferably 0.5 to 30 parts by mass, more preferably 1 to 15 parts by mass, per 100 parts by mass of the phase-change substance, from the viewpoint of solvent adsorption / desorption performance.

[0043] Known materials can be used as the material for the microcapsules, and examples thereof include polymer compounds such as resins. Examples of polymer compounds include formaldehyde-melamine resin, melamine resin, formaldehyde-urea resin, urea resin, urea-formaldehyde-polyacrylic acid copolymer, polystyrene, polyvinyl acetate, polyacrylonitrile, polyethylene, polybutyl methacrylate, and gelatin. These materials can be used alone or in combination of two or more.

[0044] The weight ratio of the microcapsule material to the phase-change substance is not particularly limited, but from the viewpoint of solvent adsorption / desorption performance, the content of the microcapsule material can usually be 10 to 30% by mass and the content of the phase-change substance can be 70 to 90% by mass, assuming the total amount of the microcapsule material and the phase-change substance to be 100% by mass. When a high-melting point compound is used, from the viewpoint of solvent adsorption / desorption performance, the content of the microcapsule material can usually be 10 to 30% by mass and the total content of the phase-change substance and the high-melting point compound can be 70 to 90% by mass, assuming the total amount of the microcapsule material, phase-change substance, and high-melting point compound to be 100% by mass.

[0045] The phase-change material used in the present invention can be microencapsulated using existing techniques such as coacervation, interfacial polymerization, in-situ, and yeast-based methods, and the effects of the present invention can be achieved using any of these techniques.

[0046] For example, a phase-change substance (and a high-melting-point compound, if necessary) is emulsified in a liquid medium using an emulsifier or the like, and an initial condensate (prepolymer) corresponding to the desired resin is added to the emulsified mixture. The mixture is then heated and the polymerization reaction is allowed to proceed, thereby preparing a microcapsule dispersion (slurry) having a resin wall and containing the phase-change substance (and a high-melting-point compound, if necessary).

[0047] As the liquid medium, water is particularly preferred, but water-miscible solvents such as alcohols such as methanol, ethanol, and propanol, and acetone can also be used. The above solvents can be used alone or in combination of two or more.

[0048] Microcapsules are usually spherical particles (powder or granules), and the particle size of these particles varies depending on factors such as the type and concentration of emulsifier used during encapsulation, the temperature and time during emulsification, and the emulsification method, so optimal conditions can be determined through experimentation. Specifically, the average particle size of the microcapsules is preferably approximately 0.1 to 500 μm, more preferably approximately 1 to 100 μm, and even more preferably approximately 2 to 10 μm. The average particle size of the microcapsules was measured using a laser diffraction particle size distribution analyzer (Microtrac MT3300EXII, manufactured by Microtrac Bell), and the particle size at 50% cumulative volume was taken as the average particle size. The measurement sample was irradiated with ultrasound for 30 minutes to break down secondary particles into primary particles.

[0049] (1-2) Latent heat storage material In the latent heat storage material, the surfaces of the microcapsules are coated with an organic binder-containing layer containing a thermosetting organic binder A. In this case, the number of microcapsules coated with the organic binder-containing layer containing a thermosetting organic binder A is not particularly limited, and may be one or more (for example, 2 to 10), but according to the production method of the present invention described below, usually one microcapsule is often coated with an organic binder-containing layer containing a thermosetting organic binder A.

[0050] The thermosetting organic binder A can be any commonly used one without any particular limitation, and examples thereof include thermosetting resins such as phenolic resin, acrylic resin, epoxy resin, isocyanate resin, melamine resin, urethane resin, and amide ester resin. Among these, thermosetting resins that tend to increase the JIS hardness (JIS K1474 (2014)) of the resulting latent heat storage material are preferred. Furthermore, the thermosetting organic binder A is preferably a resin that has high solvent resistance (water resistance, organic solvent resistance, etc.) after molding.

[0051] By using the thermosetting organic binder A having high solvent resistance as described above, the latent heat storage material can easily prevent dispersion and swelling of the microcapsules caused by solvents that can be used in the manufacturing method described below, and the hardness of the latent heat storage material can easily be maintained. Furthermore, since the hardness of the latent heat storage material tends to be high, powdering of the latent heat storage material during molding can easily be suppressed, and destruction of the powdered microcapsules by activated carbon can also be suppressed.

[0052] In the present invention, the content of the thermosetting organic binder A in the latent heat storage material is preferably 5 to 20 parts by mass, more preferably 8 to 18.5 parts by mass, and even more preferably 14.5 to 18.5 parts by mass, relative to 100 parts by mass of microcapsules encapsulating a phase-change substance, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0053] In the present invention, the organic binder-containing layer containing the thermosetting organic binder A may be composed solely of the above-mentioned thermosetting organic binder A, or may contain additives such as a curing accelerator, a colorant, a plasticizer, a stabilizer, a release agent (metal soap such as zinc stearate), etc. The content of such additives is preferably within a range that does not impair the effects of the present invention, and is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 3% by mass, where the total amount of the organic binder-containing layer is 100% by mass.

[0054] In the present invention, the shape of the latent heat storage material including the organic binder-containing layer is not particularly limited, and any shape such as pellets (cylindrical, spherical, etc.), disks, or blocks can be used.

[0055] In the present invention, the average cross-sectional diameter of the latent heat storage material, including the organic binder-containing layer, is not particularly limited, but is preferably 0.75 to 1.80 mm, more preferably 0.78 to 1.50 mm, and even more preferably 0.80 to 1.20 mm, from the viewpoint of easily suppressing the temperature rise due to the heat of adsorption of activated carbon, easily improving the amount of latent heat, easily improving adsorption performance, and easily improving durability. Note that when passing through holes such as a die of a molding machine, it is preferable to make the diameter smaller than the hole, since this easily suppresses performance degradation due to cracking of the microcapsules. The average cross-sectional diameter of the latent heat storage material is calculated using a vernier caliper.

[0056] In the present invention, the JIS hardness of the latent heat storage material in the latent heat storage material-integrated activated carbon is preferably greater than that of the latent heat storage material-integrated activated carbon of the present invention, from the viewpoint of easily suppressing cracking and pulverization due to contact between the latent heat storage material and the activated carbon. Specifically, the JIS hardness of the latent heat storage material is, for example, preferably 90% or more, more preferably 95 to 100%. The JIS hardness of the latent heat storage material is measured in accordance with JIS K1474 (2014).

[0057] (1-3) Activated carbon integrated with latent heat storage material In the activated carbon integrated with latent heat storage material of the present invention, the surface of the latent heat storage material in which an organic binder-containing layer is formed on the surface of the above-mentioned microcapsules is further coated with an activated carbon-containing layer containing activated carbon. In this case, the number of latent heat storage materials coated with the activated carbon-containing layer containing activated carbon is not particularly limited, and may be one or more (for example, 2 to 10), but according to the manufacturing method of the present invention described below, usually, one latent heat storage material is often coated with the activated carbon-containing layer containing activated carbon.

[0058] The activated carbon used in the present invention may be any of the activated carbons commonly used for canisters. Activated carbon may be obtained from various raw materials such as coal, coconut shell, wood, or lignin, and may be activated by steam, carbon dioxide, or chemicals such as phosphoric acid, zinc chloride, or alkali metals.

[0059] The activated carbon used in the present invention may be in any form, such as powder, granules, or crushed carbon, but when used in canister applications, a powdered form having fine pores is preferred in order to increase the adsorption capacity of evaporated fuel.

[0060] In the present invention, the average particle size of the activated carbon powder is not particularly limited, but is preferably 1 μm to 10 mm, more preferably 5 μm to 1 mm, and even more preferably 10 to 100 μm, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily improving the latent heat, easily improving the adsorption performance, and easily improving durability. The average particle size of the activated carbon powder is measured using a laser diffraction particle size distribution analyzer (Microtrac MT3300EXII, manufactured by Microtrac-Bell), and the particle size at 50% cumulative volume is defined as the average particle size.

[0061] In the present invention, the specific surface area of ​​the activated carbon is not particularly limited, but is preferably 500 to 2500 m from the viewpoint of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily improving the amount of latent heat, easily improving the adsorption performance, and easily improving durability. 2 / g is preferred, and 600 to 2400m 2 / g is more preferable, and 800 to 2000m2 The specific surface area of ​​activated carbon with a diameter of 30 nm or less is measured using a specific surface area / pore size distribution analyzer (Microtrack-Bel: Belsorp mini II), and the nitrogen adsorption isotherm of the activated carbon at liquid nitrogen temperature is plotted and calculated using the Cranston-Inkley (CI) method.

[0062] The pore volume of activated carbon is not particularly limited, but is preferably 0.10 to 1.00 mL / g, more preferably 0.20 to 0.90 mL / g, and even more preferably 0.30 to 0.80 mL / g, from the viewpoints of easily suppressing temperature rise due to heat of adsorption of activated carbon, easily increasing latent heat, improving adsorption performance, and easily improving durability. The pore volume of activated carbon with a diameter of 30 nm or less is measured using a specific surface area / pore distribution analyzer (Belsorp mini II, manufactured by Microtrac-Bell Co., Ltd.), and calculated by the Cranston-Inkley (CI) method using a nitrogen adsorption isotherm of the activated carbon at liquid nitrogen temperature.

[0063] In the present invention, the pH of the activated carbon is, for example, in a carboxylate state under neutral or basic conditions, and the binder is easily soluble in water, which facilitates improving the uniformity of the binder on the surface of the activated carbon and the hardness. Therefore, although not particularly limited, the pH of an aqueous suspension of activated carbon measured in accordance with JIS K 1474 (2014) is preferably 4.0 or higher, more preferably 4.5 or higher, and even more preferably 5.0 or higher. The upper limit of the pH of an aqueous suspension of activated carbon measured in accordance with JIS K 1474 (2014) is not particularly limited, but is typically about 14.0.

[0064] In the present invention, the content of the latent heat storage material in the latent heat storage material-integrated activated carbon is preferably 7 to 30 mass%, more preferably 9 to 29 mass%, and even more preferably 14 to 19 mass%, based on 100 mass% of the total amount of the latent heat storage material-integrated activated carbon, from the viewpoints of easily suppressing the amount of temperature change, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0065] In the present invention, the content of activated carbon in the activated carbon integrated with latent heat storage material is preferably 62 to 86 mass%, more preferably 63 to 84 mass%, and even more preferably 73 to 79 mass%, based on 100 mass% of the total amount of the activated carbon integrated with latent heat storage material, from the viewpoints of easily suppressing the amount of temperature change, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0066] The activated carbon-containing layer of the activated carbon integrated with latent heat storage material of the present invention may be composed of only the activated carbon described above, but may further contain an organic binder B.

[0067] As the organic binder B, thermoplastic or thermosetting resin binders commonly used in molding adsorbents such as activated carbon can be used. Other examples include paints, adhesives, fiber treatment binders, crosslinking and adhesion promoters for coating agents such as films, thermoplastic resins, and additives. For example, commonly used binders such as cellulose derivatives (e.g., methyl cellulose and carboxymethyl cellulose), phenolic resins, melamine resins, epoxy resins, urethane resins, polyvinyl alcohol, vinyl acetate, vinylidene chloride resins, and oxazoline-containing polymers can be used without limitation. These organic binders B can be used alone or in combination of two or more. Furthermore, the binder B may be the same as or different from the thermosetting organic binder A described above.

[0068] In the present invention, the content of organic binder B in the activated carbon integrated with latent heat storage material is preferably 5 to 10 mass%, more preferably 6 to 9 mass%, and even more preferably 7 to 8 mass%, based on 100 mass% of the total amount of the activated carbon integrated with latent heat storage material, from the viewpoints of making it difficult to block the pores of the activated carbon, making it easy to suppress the amount of temperature change, making it easy to increase the amount of latent heat, making it easy to improve the adsorption performance, and making it easy to improve durability and hardness.

[0069] The activated carbon-containing layer of the activated carbon integrated with latent heat storage material of the present invention can be composed only of the above-mentioned activated carbon and, if necessary, the organic binder B. As described above, under neutral or basic conditions, it is easy to improve the uniformity of the binder on the surface of the activated carbon and to improve hardness, and therefore the pH can be adjusted with a pH adjuster.

[0070] The pH adjuster can be any acid, base, salt, buffer solution, etc. Examples include bases such as sodium hydroxide, potassium hydroxide, barium hydroxide, ammonia, magnesium hydroxide, calcium hydroxide, and aluminum hydroxide; acids such as hydrochloric acid, nitric acid, phosphoric acid, boric acid, acetic acid, citric acid, and carbonic acid; salts such as sodium hydrogencarbonate, sodium carbonate, sodium acetate, sodium dihydrogenphosphate, sodium hydrogenphosphate, and sodium hydrogensulfate; and buffer solutions that combine these.

[0071] In the present invention, the content of the pH adjuster in the latent heat storage material-integrated activated carbon is preferably 0 to 10 mass%, more preferably 0 to 5 mass%, based on the total amount of the latent heat storage material-integrated activated carbon being 100 mass%, from the viewpoint of easily improving the uniformity of the binder on the surface of the activated carbon and easily improving hardness.

[0072] In the present invention, the activated carbon-containing layer containing activated carbon may be composed only of the above-mentioned activated carbon and, if necessary, organic binder B, or may contain additives such as a crosslinking agent, a colorant, a plasticizer, a stabilizer, a release agent (metal soap such as zinc stearate), etc. The content of such additives is preferably within a range that does not impair the effects of the present invention, and is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 3% by mass, assuming the total amount of the activated carbon-containing layer to be 100% by mass.

[0073] In the present invention, the pH of the activated carbon-containing layer is, for example, in a neutral or basic state, in the form of a carboxylate, which is easily soluble in water, and therefore it is easy to improve the uniformity of the binder on the surface of the activated carbon and to improve hardness. Therefore, although not particularly limited, the pH of the aqueous suspension of the activated carbon-containing layer measured in accordance with JIS K 1474 (2014) is preferably 4.5 or higher, more preferably 5.5 or higher, and even more preferably 6.0 or higher. The upper limit of the pH of the aqueous suspension of the activated carbon-containing layer measured in accordance with JIS K 1474 (2014) is not particularly limited, but is usually about 14.0.

[0074] In the present invention, the thickness of the activated carbon-containing layer containing activated carbon is not particularly limited, but from the viewpoints of easily suppressing a temperature rise due to the heat of adsorption of activated carbon, easily improving the amount of latent heat, easily improving adsorption performance, and easily improving durability, it is preferably 180 to 2050 μm, more preferably 250 to 900 μm, and even more preferably 350 to 780 μm. The thickness of the activated carbon-containing layer is measured with a vernier caliper after splitting the monolithic carbon and removing the heat storage material.

[0075] The shape of the above-mentioned latent heat storage material-integrated activated carbon of the present invention is not particularly limited, but for example, according to the manufacturing method described below, it is likely to be spherical or oval.

[0076] The average particle size of the activated carbon integrated with latent heat storage material of the present invention is not particularly limited, but is preferably 1.0 to 4.0 mm, more preferably 1.2 to 3.4 mm, and even more preferably 1.7 to 2.8 mm, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily improving the amount of latent heat, easily improving the adsorption performance and durability, easily reducing the airflow resistance, and easily improving the air flow in the canister. The average particle size of the activated carbon integrated with latent heat storage material of the present invention is calculated as the mass average particle size by sieving using a rotor and a sieve in accordance with JIS K1474 (2014).

[0077] The calorific value of the thus obtained activated carbon integrated with latent heat storage material of the present invention can be 10 to 100 J / g, preferably 11 to 80 J / g, and more preferably 12 to 60 J / g. Therefore, the activated carbon integrated with latent heat storage material of the present invention is likely to suppress the temperature rise caused by the heat of adsorption of the activated carbon, and is likely to improve the adsorption / desorption performance, durability, hardness, etc. The calorific value of the latent heat storage material is measured using a DSC7020 (differential scanning calorimeter, manufactured by Seiko Instruments Inc.).

[0078] The pH of the activated carbon integrated with a latent heat storage material of the present invention is, for example, in a neutral or basic state, and is easily soluble in water in a carboxylate state, which facilitates improving the uniformity of the binder on the surface of the activated carbon and improving hardness. Therefore, although not particularly limited, the pH of an aqueous suspension of the activated carbon integrated with a latent heat storage material of the present invention, measured in accordance with JIS K 1474 (2014), is preferably 4.5 or higher, more preferably 5.5 or higher, and even more preferably 6.0 or higher. The upper limit of the pH of an aqueous suspension of the activated carbon integrated with a latent heat storage material of the present invention, measured in accordance with JIS K 1474 (2014), is not particularly limited, but is typically around 14.0.

[0079] The thus obtained activated carbon with integrated latent heat storage material of the present invention can have a high hardness. Specifically, the ASTM hardness of the activated carbon with integrated latent heat storage material of the present invention is preferably 45% or more, more preferably 48 to 80%, and even more preferably 50 to 80%. The ASTM hardness of the activated carbon with integrated latent heat storage material of the present invention is measured in accordance with ASTM-D5228.

[0080] The thus obtained activated carbon integrated with latent heat storage material of the present invention can have a high butane activity (BA), which indicates the fuel evaporation gas adsorption performance. Specifically, the butane activity (BA) of the activated carbon integrated with latent heat storage material of the present invention is preferably 42% or more, more preferably 43 to 60%, and even more preferably 44 to 53%. It is known that a butane activity (BA) of 42% or more indicates excellent fuel evaporation gas adsorption performance. The butane activity (BA) of the activated carbon integrated with latent heat storage material of the present invention is measured in accordance with ASTM-D5228.

[0081] The activated carbon integrated with a latent heat storage material of the present invention as described above can be filled into a canister container and evaporated fuel gas from a fuel tank can be introduced into the container to form a canister, which can adsorb the evaporated fuel gas. There is no particular limitation on the canister that adsorbs evaporated fuel generated in a fuel tank, and existing canisters can be used. For example, for automotive applications, there are canisters connected to sealed fuel tanks or regular fuel tanks. The sealed fuel tank or regular fuel tank and the canister can be connected directly, or indirectly via a shutoff valve or an open valve.

[0082] The temperatures of the gas and the container are preferably equal to or lower than the phase change temperature (usually the melting point) of the phase change substance. In other words, the activated carbon integrated with a latent heat storage material of the present invention is useful as an activated carbon integrated with a latent heat storage material for a canister.

[0083] Examples of evaporated fuel gases to which the latent heat storage material integrated spherical activated carbon of the present invention can be applied include hydrocarbons, ketones, halogens, alcohols, esters, automotive gasoline, and the like, which are often used in solvent recovery.

[0084] 2. Manufacturing method of activated carbon integrated with latent heat storage material The method for producing the latent heat storage material-integrated activated carbon of the present invention is not particularly limited, but may be, for example, (1) A step of mixing the microcapsules with the thermosetting organic binder A (2) a step of coating the microcapsule composition obtained in step (1) with the thermosetting organic binder A and heat-treating the coated microcapsule composition to obtain the latent heat storage material; (3) A step of mixing the latent heat storage material obtained in step (2) with a composition containing the activated carbon and granulating the mixture. The method can be carried out by the steps of:

[0085] (2-1) Process (1) In step (1), first, the microcapsules are mixed with the thermosetting organic binder A. Specifically, in step (1), it is preferable to mix the microcapsules with the thermosetting organic binder A, extrude the mixture, granulate it, and then size it. In this case, the thermosetting organic binder A is used to mix with the microcapsules, not to coat the surface of the microcapsules.

[0086] In the present invention, the amount of thermosetting organic binder A added is preferably 5 to 30 parts by mass, more preferably 8 to 25 parts by mass, and even more preferably 10 to 20 parts by mass, relative to 100 parts by mass of microcapsules, from the viewpoints of making it easier to improve the binding strength of the latent heat storage material obtained in step (2), making it easier to improve hardness and solvent resistance, making the microcapsules less likely to be broken, making it easier to improve the amount of latent heat and improve adsorption performance, and making it easier to improve dispersibility during mixing and suppress unevenness of the material.

[0087] In the present invention, there are no particular limitations on the method for mixing the microcapsules with the thermosetting organic binder A. For example, the microcapsules and the thermosetting organic binder A may be mixed in a solvent by a conventional method to form a slurry.

[0088] The solvent that can be used in this case is not particularly limited, and a common solvent can be used, such as water, alcohol (methanol, ethanol, etc.), a mixture thereof, etc. When the thermosetting organic binder A is in the form of a solution, dispersion, suspension, etc., a solvent may not be used.

[0089] The amount of solvent added is preferably 3 to 50 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 10 to 20 parts by mass, per 100 parts by mass of microcapsules, from the viewpoints of easily suppressing cracking and powdering after molding and easily increasing the packing density of the microcapsules. When the thermosetting organic binder A is in the form of a solution, dispersion, suspension, or the like, the total amount including the solvent present in the thermosetting organic binder A can be set within the above range.

[0090] Thereafter, extrusion granulation is not particularly limited and can be carried out by a conventional method, and molding can be performed using a general granulator such as an agitation granulator, a compression granulator, an extrusion granulator, a rolling granulator, etc. Thereafter, if necessary, the mixture can be granulated into fine particles to obtain a latent heat storage material of the desired size using a die such as a screen die, a disk die, or a dome-shaped die, and the particles can be further sized by rolling at about 50 to 1000 rpm using a pan-type granulator, a drum mixer, a marumerizer, etc.

[0091] (2-2) Process (2) Step (2) is a step in which the microcapsule composition obtained in step (1) is coated with a thermosetting organic binder A and heat-treated to obtain a latent heat storage material.

[0092] The thermosetting organic binder A used in this step may be the same as or different from the thermosetting organic binder A used in step (1).

[0093] As described above, it is preferable to use a thermosetting organic binder A that provides a latent heat storage material with high solvent resistance (water resistance, organic solvent resistance, etc.) after curing. For example, with regard to water resistance, it is preferable that the latent heat storage material does not become cloudy even when immersed in 50°C water for 24 hours after curing, and more preferably does not become cloudy even when immersed in 70°C water for 24 hours. Furthermore, with regard to organic solvent resistance, it is preferable that the amount of phase change substance leaching into an organic solvent (e.g., hexane, gasoline, etc.) after immersion in a 30°C organic solvent for 24 hours after curing is 15% by mass or less, more preferably 10% by mass or less, based on the total amount of phase change substance in the latent heat storage material. In particular, water-resistant thermosetting resin binders such as phenolic resins, acrylic resins, melamine resins, and amide ester resins are preferable.

[0094] The amount of thermosetting organic binder A added to coat the microcapsule composition obtained in step (1) is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, and even more preferably 1.5 to 3 parts by mass, based on 100 parts by mass of the total amount of the microcapsule composition obtained in step (1), from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0095] There are no particular limitations on the method for coating the microcapsule composition obtained in step (1) with the thermosetting organic binder A. For example, coating can be performed in a solvent using a one-fluid nozzle, a two-fluid nozzle, or the like.

[0096] The solvent that can be used in this case is not particularly limited, and a common solvent can be used, such as water, alcohol (methanol, ethanol, etc.), a mixture thereof, etc. When the thermosetting organic binder A is in the form of a solution, dispersion, suspension, etc., a solvent may not be used.

[0097] The amount of solvent added is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, and even more preferably 1.5 to 3 parts by mass, based on 100 parts by mass of the total amount of the microcapsule composition obtained in step (1), from the viewpoints of easily suppressing cracking and powdering after molding, easily suppressing temperature rise due to heat of adsorption of activated carbon, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability. When the thermosetting organic binder A is in the form of a solution, dispersion, suspension, or the like, the total amount including the solvent present in the thermosetting organic binder A can be within the above range.

[0098] The heating temperature during the heat treatment is not particularly limited, and is preferably 100 to 300°C, more preferably 150 to 250°C, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving the adsorption performance, and easily improving durability.

[0099] The heating time during the heat treatment is not particularly limited, but is preferably 30 to 180 minutes, more preferably 60 to 150 minutes, since this makes it easy to complete the curing reaction and improve durability.

[0100] By the above heat treatment, the thermosetting organic binder A is cured, and the latent heat storage material can be obtained.

[0101] (2-3) Process (3) Step (3) is a step of mixing the latent heat storage material obtained in step (2) with a composition containing activated carbon and granulating the mixture, thereby coating the latent heat storage material obtained in step (2) with an activated carbon-containing layer, and producing the latent heat storage material-integrated activated carbon of the present invention.

[0102] The composition containing activated carbon is capable of forming the activated carbon-containing layer described above, and may contain, in addition to activated carbon, the organic binder B and a pH adjuster as necessary.

[0103] In a composition containing activated carbon, the content of organic binder B is preferably 0.5 to 20 parts by mass, and more preferably 6 to 11 parts by mass, relative to 100 parts by mass of activated carbon, from the viewpoints of easily suppressing a temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0104] In a composition containing activated carbon, the content of the pH adjuster is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, per 100 parts by mass of activated carbon, from the viewpoint of easily improving the uniformity of the binder on the surface of the activated carbon and easily improving hardness.

[0105] When using activated carbon obtained by chemical activation such as alkali activation, zinc chloride activation, or phosphoric acid activation, it is preferable to wash or neutralize the activated carbon before mixing to remove the chemicals contained in the activated carbon. The washing method may be a general washing method for chemically activated carbon. For example, in the case of phosphoric acid activated carbon, it can be washed with hot or cold water and then dried. A basic aqueous solution such as an aqueous ammonium carbonate solution may be used instead of hot or cold water.

[0106] The composition containing activated carbon may contain a solvent from the viewpoint of easily suppressing cracking and powdering after molding.

[0107] The solvent that can be used in this case is not particularly limited, and a common solvent can be used, such as water, alcohol (methanol, ethanol, etc.), a mixture thereof, etc. When the organic binder B is in the form of a solution, dispersion, suspension, etc., a solvent may not be used.

[0108] The amount of solvent added is preferably 50 to 1500 parts by mass, more preferably 100 to 500 parts by mass, and even more preferably 300 to 650 parts by mass, per 100 parts by mass of activated carbon, from the viewpoints of easily suppressing cracking and powdering after molding, easily suppressing temperature rise due to heat of adsorption of activated carbon, easily increasing latent heat, easily improving adsorption performance, and easily improving durability. When organic binder B is in the form of a solution, dispersion, suspension, or the like, the total amount including the solvent present in organic binder B can be within the above range.

[0109] Thereafter, the method for mixing the latent heat storage material obtained in step (2) with a composition containing activated carbon and granulating it (coating the latent heat storage material obtained in step (2) with an activated carbon-containing layer) is not particularly limited, and any conventionally known granulation method can be used. Examples of the method include, without limitation, an extrusion granulation method, in which a binder is added to the composition containing the latent heat storage material and activated carbon obtained in step (2), kneading the mixture, and extruding the mixture through a screen to form granules; a crushing granulation method, in which the kneaded mass prepared by the above-mentioned method is cut with the rotating blade of a granulator and ejected through the outer screw holes by centrifugal force; a tumbling granulation method, in which a binder is added to the composition containing the latent heat storage material and activated carbon obtained in step (2), and the humidified powder is subjected to rotational motion or vibration to agglomerate and obtain nearly spherical particles; a fluidized bed granulation method, in which the composition containing the latent heat storage material and activated carbon obtained in step (2) is fluidized from below by a hot air current, and a binder is sprayed onto it to granulate; and an agitation granulation method, in which the composition containing the latent heat storage material and activated carbon obtained in step (2) is placed in a container, and water or a granulation liquid is added while stirring with a rotating blade, thereby agglomerating the raw material powder particles into spherical shapes. In this case, molding can be performed using a marumerizer, spray granulation, fluidized bed granulation, stirring granulator, pan type granulator, or the like.

[0110] The amount of the composition containing activated carbon to be used is not particularly limited, and is preferably 200 to 1000 parts by mass, more preferably 250 to 600 parts by mass, relative to 100 parts by mass of the latent heat storage material obtained in step (2), from the viewpoints of easily suppressing cracking and powdering after molding, easily suppressing temperature rise due to heat of adsorption of activated carbon, easily increasing the amount of latent heat, easily improving adsorption performance, and easily improving durability.

[0111] In this case, the binder is not particularly limited, and examples thereof include cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hypromellose, and carboxymethyl cellulose; crystalline cellulose, polyvinyl alcohol, polyvinylpyrrolidone (povidone), vinylpyrrolidone copolymer (copolyvidone), acrylic acid polymers, gelatin, gum arabic, pullulan, agar, tragacanth, sodium alginate, propylene glycol alginate, pregelatinized starch, dextrin, macrogol, and sucrose. These binders can also be used in the form of a solution such as an aqueous solution. These binders can be used alone or in combination of two or more.

[0112] The amount of the binder used is preferably 15 to 100 parts by mass, more preferably 17 to 85 parts by mass, in terms of solid content, per 100 parts by mass of the latent heat storage material obtained in step (2), from the viewpoint of easily suppressing cracking and powdering after molding.

[0113] Thereafter, it is preferable to carry out a heat treatment in order to facilitate molding of the activated carbon integrated with latent heat storage material of the present invention.

[0114] The heating temperature during the heat treatment is not particularly limited, and is preferably 80 to 250°C, more preferably 100 to 200°C, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving the adsorption performance, and easily improving durability.

[0115] The heating time during the heat treatment is not particularly limited, and can be set to a time period that allows for the production of spherical activated carbon with a sufficiently small particle size and high sphericity, and is preferably 10 minutes to 12 hours, more preferably 30 minutes to 6 hours, from the viewpoints of easily suppressing the temperature rise due to the heat of adsorption of the activated carbon, easily increasing the amount of latent heat, easily improving the adsorption performance, and easily improving durability. In this case, it is preferable to adjust the moisture content of the obtained activated carbon integrated with latent heat storage material of the present invention to 10 mass % or less, particularly 5 mass % or less. [Example]

[0116] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the embodiments of the examples.

[0117] In the following examples and comparative examples, the average particle size of the microcapsules was measured using a laser diffraction particle size distribution measuring device (Microtrac MT3300EXII, manufactured by Microtrac-Bell Co., Ltd.), the average cross-sectional diameter of the latent heat storage material was measured for 10 pellets using a vernier caliper, and the calorific value of the latent heat storage material was measured using a DSC7020 (differential scanning calorimeter, manufactured by Seiko Instruments Inc.).

[0118] In the following examples and comparative examples, the term "existing method" refers to an in-situ method using a formalin-condensed resin precondensate. The microcapsules were prepared by the following procedure: A styrene-maleic anhydride copolymer sodium salt aqueous solution, adjusted to pH 4.5, was vigorously stirred with a homomixer. A phase-change substance with a predetermined phase transition temperature was gradually added to the aqueous solution, with twice the molar ratio of the emulsifier. The mixture was emulsified until the average particle size reached 3.0-4.0 μm. Meanwhile, melamine, formaldehyde, and water were mixed in a molar ratio of 1:2:7, adjusted to pH 10, and heated to 60°C with stirring to obtain a precondensate. The emulsion was transferred to a separate container, to which melamine-formaldehyde precondensate was added. The mixture was then reacted at 80°C for 3 hours to obtain an aqueous dispersion (40% solids by weight) of microcapsules with a 17% melamine membrane ratio. The pH was then adjusted to 9, and encapsulation was performed. Polyvinyl alcohol was added to the aqueous dispersion of the microcapsules so that the content was 0.5% by mass, and the mixture was stirred again, and then dried by spray drying to obtain microcapsules.

[0119] The pH of the activated carbon or activated carbon with integrated latent heat storage material was measured in accordance with JIS K 1474 (2014) by adding 1.0 g of activated carbon, or 3.0 g of the activated carbon with integrated latent heat storage material or the molded products of the manufacturing examples and comparative manufacturing examples to 100 mL of water, heating for 5 minutes so that the water continued to boil, and then cooling to room temperature. Water was added to make 100 mL, and the pH of the resulting aqueous suspension was measured using a pH meter.

[0120] Example 1 The microcapsules used were covered with a melamine membrane and were prepared by a conventional method, and contained straight-chain aliphatic hydrocarbons with a phase transition temperature of 50-52°C.

[0121] To 100 parts by mass of the above-mentioned microcapsules, 17 parts by mass of a thermosetting phenolic organic binder (Phenolite 1480 manufactured by DIC Corporation; solid content 68.7% by mass) and 18 parts by mass of water were added and mixed. The mixture was then molded using an extruder (Disc Pelleter F5 manufactured by Dalton Co., Ltd.). At this time, the particles were refined using a screen die with an opening of 1.0 mm. Thereafter, the particles were sized at 275 rpm for 2 minutes using a Marumerizer (QJ-400 manufactured by Dalton Co., Ltd.) to obtain a microcapsule composition.

[0122] Next, the obtained microcapsule composition was used to coat with the same thermosetting phenolic binder as above. Specifically, 1.5 parts by mass of the above thermosetting phenolic binder and an equal part of water as a solvent were added to 100 parts by mass of the obtained microcapsule composition, and the thermosetting phenolic binder was coated on the microcapsules using a one-fluid nozzle, and the material temperature was set to 160°C or higher, and dried for 2 hours to obtain a latent heat storage material.

[0123] Activated carbon, an organic binder, and water were kneaded and crushed to obtain a mixture (a composition containing activated carbon). The organic binders were selected from carboxymethylcellulose sodium salt (F30MC manufactured by Nippon Paper Industries Co., Ltd.), Epocross WS-700 (an oxazoline group-containing water-soluble polymer manufactured by Nippon Shokubai Co., Ltd.), and ADEKA Resin (an aqueous epoxy resin EM-0180 manufactured by ADEKA Corporation), with solid contents of 7.2 parts by mass, 1.2 parts by mass, and 2.1 parts by mass, respectively, for a total of 10.5 parts by mass per 100 parts by mass of activated carbon. 160.5 parts by mass of water was added per 100 parts by mass of activated carbon.

[0124] Next, using the obtained latent heat storage material of Example 1 as a core, 250 g was put into a granulator (manufactured in-house), and while spraying 1.5 to 2.0 L of 0.01 mass% PVA solution water, while fluidizing, the above mixture (composition containing activated carbon) was coated (thickness 730 μm) so that 1540 g of the total amount was used (latent heat storage material: activated carbon: organic binder = 250: 1395: 146 (mass ratio)). Then, it was dried at 115 ° C. for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass%, and the average particle size was adjusted to 2.4 to 2.8 mm, and the latent heat storage material-integrated activated carbon of Example 1 was obtained.

[0125] Example 2 A latent heat storage material was obtained in the same manner as in Example 1, except that microcapsules covered with a melamine film and produced by an existing method, containing a linear aliphatic hydrocarbon having a phase transition temperature of 45 to 47°C as an encapsulant, were used. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Example 2 was obtained.

[0126] Example 3 A latent heat storage material was obtained in the same manner as in Example 1, except that melamine-coated microcapsules, produced by a conventional method and containing linear aliphatic hydrocarbons (carbon number 22) with a phase transition temperature of 42 to 45°C as encapsulants, were used and pulverized using a screen die with an opening of 0.8 mm. A composition containing activated carbon was then subjected to coating (thickness: 660 μm) so that a total of 1924 g was used (latent heat storage material: activated carbon: organic binder = 250:1742:182 (mass ratio)). The resulting product was then dried at 115°C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass% and the average particle size was adjusted to 2.0 to 2.4 mm. A latent heat storage material-integrated activated carbon of Example 3 was obtained in the same manner as in Example 1, except that the activated carbon was then coated (thickness: 660 μm) so that a total of 1924 g was used. The resulting product was then dried at 115°C for 3 hours or more, and the molded product was adjusted to have a moisture content of less than 5 mass% and an average particle size of 2.0 to 2.4 mm.

[0127] Example 4 A latent heat storage material was obtained in the same manner as in Example 1, except that microcapsules covered with a melamine film and produced by an existing method, containing a linear aliphatic hydrocarbon (having a carbon number of 22) having a phase transition temperature of 42 to 45°C, were used. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Example 4 was obtained.

[0128] Example 5 A latent heat storage material was obtained in the same manner as in Example 1, except that melamine-coated microcapsules, produced by a conventional method and containing linear aliphatic hydrocarbons (carbon number 22) with a phase transition temperature of 42 to 45°C as encapsulants, were used and pulverized using a screen die with an opening of 1.2 mm. A composition containing activated carbon was then coated (thickness: 535 μm) so that a total of 640 g was used (latent heat storage material: activated carbon: organic binder = 250:579:61 (mass ratio)). The resulting product was then dried at 115°C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass% and the average particle size was adjusted to 2.0 to 2.4 mm. A latent heat storage material-integrated activated carbon of Example 5 was obtained in the same manner as in Example 1, except that the composition was dried at 115°C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass%, and the average particle size was adjusted to 2.0 to 2.4 mm.

[0129] Example 6 A latent heat storage material was obtained in the same manner as in Example 1, except that microcapsules covered with a melamine film and produced by an existing method, containing a linear aliphatic hydrocarbon (having 20 carbon atoms) with a phase transition temperature of 32 to 37°C, were used. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Example 6 was obtained.

[0130] Example 7 A latent heat storage material was obtained in the same manner as in Example 1, except that microcapsules covered with a melamine film and produced by an existing method, containing a linear aliphatic hydrocarbon (carbon number 16) having a phase transition temperature of 18°C, were used. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Example 7 was obtained.

[0131] Comparative Example 1 A microcapsule composition was produced in the same manner as in Example 1 using the microcapsules used in Example 1 as microcapsules covered with a melamine film, which were produced by a conventional method and contained a linear aliphatic hydrocarbon having a phase transition temperature of 50 to 52°C as an inclusion. This was used as a latent heat storage material. In other words, the surface of the microcapsules was not coated with a thermosetting organic binder. Thereafter, a latent heat storage material-integrated activated carbon of Comparative Example 1 was obtained in the same manner as in Example 1.

[0132] Comparative Example 2 A microcapsule composition was produced in the same manner as in Example 1 using microcapsules covered with a melamine film, which were produced by a conventional method and contained a linear aliphatic hydrocarbon having a phase transition temperature of 45 to 47°C as an inclusion. This was used as a latent heat storage material. In other words, the surface of the microcapsules was not coated with a thermosetting organic binder. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Comparative Example 2 was obtained.

[0133] Comparative Example 3 A microcapsule composition was produced in the same manner as in Example 1 using microcapsules covered with a melamine film, which were produced by a conventional method and contained a linear aliphatic hydrocarbon (having 22 carbon atoms) with a phase transition temperature of 42 to 45°C as an inclusion. This was used as a latent heat storage material. In other words, the surface of the microcapsules was not coated with a thermosetting organic binder. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Comparative Example 3 was obtained.

[0134] Comparative Example 4 A microcapsule composition was produced in the same manner as in Example 1 using microcapsules covered with a melamine film, which were produced by a conventional method and contained a linear aliphatic hydrocarbon (having 20 carbon atoms) with a phase transition temperature of 32 to 37°C as an inclusion, and used as a latent heat storage material. In other words, the surface of the microcapsules was not coated with a thermosetting organic binder. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Comparative Example 4 was obtained.

[0135] Comparative Example 5 A microcapsule composition was produced in the same manner as in Example 1 using microcapsules covered with a melamine film, which were produced by a conventional method and contained a linear aliphatic hydrocarbon (carbon number 16) having a phase transition temperature of 18°C ​​as an inclusion, and used as a latent heat storage material. In other words, the surface of the microcapsules was not coated with a thermosetting organic binder. Thereafter, in the same manner as in Example 1, a latent heat storage material-integrated activated carbon of Comparative Example 5 was obtained.

[0136] Comparative Example 6 A latent heat storage material was obtained in the same manner as in Example 1, except that melamine-coated microcapsules, which were produced by a conventional method and contained linear aliphatic hydrocarbons (22 carbon atoms) with a phase transition temperature of 42 to 45°C, were pulverized using a screen die with an opening of 0.7 mm. A composition containing activated carbon was subjected to coating (thickness: 800 μm) so that a total of 4140 g was used (latent heat storage material: activated carbon: organic binder = 250:3748:392 (mass ratio)). The resulting mixture was then dried at 115°C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass% and the average particle size was adjusted to 2.0 to 2.4 mm. A latent heat storage material-integrated activated carbon of Comparative Example 6 was obtained in the same manner as in Example 1, except that the composition was dried at 115°C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass%, and the average particle size was adjusted to 2.0 to 2.4 mm.

[0137] Test Example 1 Three grams of the activated carbon with integrated latent heat storage material obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were placed in a portable pressure reactor (TVS-1 model, manufactured by Taiatsu Glass Industry Co., Ltd.), and 10 mL of gasoline was added. After heat treatment at 70°C for 48 hours, the activated carbon with integrated latent heat storage material was placed on a petri dish, rinsed with 30 mL of hexane (special grade reagent, manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), and then dried at 40°C for 2 hours using a low-temperature air blower dryer (DK340S, manufactured by Yamato Scientific Co., Ltd.). The calorific value was then measured using a DSC7020 differential scanning calorimeter (manufactured by Seiko Instruments Inc.). The calorific value after gasoline treatment was divided by the calorific value before treatment to calculate the residual calorific value. The results are shown in Table 1.

[0138] [Table 1]

[0139] Comparing Examples 1 to 7 with Comparative Examples 1 to 5, it was found that coating the outer surface of the microcapsules with a thermosetting organic binder resulted in a high residual rate of 93% or more of the calorific value of the latent heat storage material after the gasoline immersion test, whereas the absence of the coating significantly reduced the residual calorific value (53 to 56%). This demonstrates the significant effect of coating the microcapsules with a thermosetting organic binder. Furthermore, the same tendency was observed regardless of the type of phase-change material.

[0140] On the other hand, when the average cross-sectional diameter of the latent heat storage material is smaller than 0.7 mm as in Comparative Example 6, the durability test using a gasoline immersion test results in a significant decrease in durability performance because more gasoline penetrates into the pellets.

[0141] After carrying out Test Example 1, SEM images of the latent heat storage material in the latent heat storage material-integrated activated carbon coated with a thermosetting organic binder (Example 4) and the latent heat storage material in the latent heat storage material-integrated activated carbon not coated with a thermosetting organic binder (Comparative Example 3) are shown in Figures 1 and 2. Each latent heat storage material was evaluated by hitting it with a hammer to remove the activated carbon-containing layer from the surface of the latent heat storage material-integrated activated carbon. The material coated with the thermosetting organic binder had few cracks, while the material not coated with the thermosetting organic binder had many cracks, indicating that the inclusions inside were released by the solvent, resulting in a decrease in the residual heat.

[0142] Example 8 Activated carbon, an organic binder, and water were kneaded and crushed to obtain a mixture (a composition containing activated carbon). The organic binders were selected from carboxymethylcellulose sodium salt (F30MC manufactured by Nippon Paper Industries Co., Ltd.), Epocross WS-700 (an oxazoline group-containing water-soluble polymer manufactured by Nippon Shokubai Co., Ltd.), and ADEKA Resin (an aqueous epoxy resin EM-0180 manufactured by ADEKA Corporation), with solid contents of 7.2 parts by mass, 1.2 parts by mass, and 2.1 parts by mass, respectively, for a total of 10.5 parts by mass per 100 parts by mass of activated carbon. 160.5 parts by mass of water was added per 100 parts by mass of activated carbon.

[0143] Next, using the latent heat storage material obtained in Example 3 as a core, 250 g was put into a granulator (manufactured in-house), and while spraying 1.5 to 2.0 L of 0.01 mass% PVA solution water, the mixture (composition containing activated carbon) was coated (thickness 760 μm) so that the total amount of 2560 g was used (latent heat storage material: activated carbon: organic binder = 250: 2317: 242 (mass ratio)). After that, it was dried at 115 ° C for 3 hours or more, and the moisture content of the molded product was adjusted to less than 5 mass%, and the average particle size was adjusted to 2.0 to 2.4 mm, and the latent heat storage material-integrated activated carbon of Example 8 was obtained.

[0144] Example 9 The latent heat storage material obtained in Example 4 was used as the latent heat storage material, and the activated carbon mixture (composition containing activated carbon) was subjected to coating (thickness 640 μm) so that a total of 1,187 g was used (latent heat storage material: activated carbon: organic binder = 250:1074:112 (mass ratio)), and the rest was the same as in Example 8, to obtain the latent heat storage material-integrated activated carbon of Example 9.

[0145] Example 10 The latent heat storage material obtained in Example 5 was used as the latent heat storage material, and the activated carbon mixture (composition containing activated carbon) was coated (thickness 530 μm) so that a total of 620 g was used (latent heat storage material: activated carbon: organic binder = 250:562:59 (mass ratio)), and the rest was the same as in Example 8, to obtain the latent heat storage material-integrated activated carbon of Example 10.

[0146] Test Example 2 Butane activity (BA), which indicates the fuel evaporative gas adsorption performance, was measured in accordance with ASTM-D5228 (hereinafter abbreviated as BA). The spherical activated carbon integrated with latent heat storage material used was limited to those with an average particle diameter of 2.36 mm or more and less than 2.80 mm. The results are shown in Tables 2 and 3.

[0147] [Table 2]

[0148] The diameter size and blending ratio of the latent heat storage material suitable for the latent heat storage material-integrated spherical activated carbon can be confirmed from Examples 8 to 10. That is, if the diameter of the latent heat storage material is within an appropriate range, the BA value is 42% or more, which also means that high adsorption and desorption capacity can be obtained.

[0149] Example 11 The latent heat storage material obtained in Example 4 was used as a core, and the activated carbon mixture (composition containing activated carbon) was coated (thickness 1000 μm) so that 2854 g of the total amount was used (latent heat storage material: activated carbon: organic binder = 250:2583:270 (mass ratio)), and the other procedures were the same as in Example 8 to obtain latent heat storage material-integrated activated carbon of Example 11. At this time, the mixture was sieved using a sieve with a mesh size of 3.5 (mesh size 5.6 mm) to 10 Mesh (mesh size 1.7 mm) (JIS standard), and any latent heat storage material-integrated spherical activated carbon was obtained, excluding the fraction larger than the target particle size and the fraction finer than 10 Mesh.

[0150] Example 12 The latent heat storage material obtained in Example 4 was used as the core of the latent heat storage material, and the activated carbon mixture (composition containing activated carbon) was coated (thickness 840 μm) so that 2000 g of the mixture was used in total (latent heat storage material: activated carbon: organic binder = 250:1811:189 (mass ratio)), and the same procedure as in Example 11 was otherwise carried out to obtain the latent heat storage material-integrated activated carbon of Example 12.

[0151] Example 13 The latent heat storage material obtained in Example 4 was used as a core for the latent heat storage material, and the activated carbon mixture (composition containing activated carbon) was coated (thickness 680 μm) so that a total of 1,347 g was used (latent heat storage material: activated carbon: organic binder = 250:1220:127 (mass ratio)), and the rest was the same as in Example 11, to obtain the latent heat storage material-integrated activated carbon of Example 12.

[0152] Example 14 The latent heat storage material obtained in Example 5 was used as a core for the latent heat storage material, and the activated carbon mixture (composition containing activated carbon) was coated (thickness 560 μm) so that a total of 691 g was used (latent heat storage material: activated carbon: organic binder = 250:625:65 (mass ratio)). Except for this, the latent heat storage material-integrated activated carbon of Example 12 was obtained in the same manner as in Example 11.

[0153] Reference example 1 We used existing activated carbon (BAX1100 manufactured by Ingevity Corporation) that does not use latent heat storage material.

[0154] Reference example 2 We used existing activated carbon (BAX1700 manufactured by Ingevity Corporation) that does not use latent heat storage material.

[0155] Test Example 3 A canister case with an L / D ratio of 3.0 was used, and 1000 mL of activated carbon integrated with a latent heat storage material or activated carbon was filled. The refueling conditions (ORVR test conditions specified by the EPA) were the temperature of the remaining liquid gasoline in the tank at 26.8°C, the temperature of the gasoline being refueled at 19.2°C, and the gasoline stop condition at 3000 ppm breakthrough. Adsorption and desorption were repeated six times using gasoline fuel as pretreatment for the activated carbon integrated with a latent heat storage material or activated carbon. L / D is the value calculated by dividing the length L [mm] in the central axis direction of the activated carbon layer by the average diameter D [mm]. The results are shown in Table 3 as relative values, with Reference Example 1 as the standard (100).

[0156] Test Example 4 The ASTM hardness was measured with reference to ASTM-D5228, and the results are shown in Table 3.

[0157] [Table 3]

[0158] By comparing Examples 11 to 14 with Reference Examples 1 and 2, it can be seen that the use of activated carbon integrated with latent heat storage material significantly improves GWC (relative value of 172 or more) compared to existing activated carbon (BAX1100 manufactured by Ingevity Corporation) that does not use latent heat storage material.

[0159] Manufacturing Example 1 The activated carbon used was one with a pH of 4.19 in its aqueous suspension, measured according to JIS K 1474 (2014). This activated carbon was mixed with an organic binder and water, and extruded using an extruder (Dalton Co., Ltd., Disc Pellet F5) with a die with a hole diameter of 2.2 mm and a thickness of 15 mm. The pellets were then refined using a Marumerizer (Dalton, Q-400T) to obtain a molded product with the same material composition as the activated carbon-containing layer of the heat storage material-integrated activated carbon. The pH of the resulting molded product, measured according to JIS K 1474 (2014), was 4.97 in its aqueous suspension. There is a positive correlation between the hardness of the molded product and the hardness of the heat storage material-integrated activated carbon. The organic binders selected were carboxymethylcellulose sodium salt (F30MC manufactured by Nippon Paper Industries Co., Ltd.), Epocross WS-700 (an oxazoline group-containing water-soluble polymer manufactured by Nippon Shokubai Co., Ltd.), and ADEKA Resin (aqueous epoxy resin EM-0180 manufactured by ADEKA Corporation), with solid contents of 6.8 parts by mass, 1.2 parts by mass, and 1.9 parts by mass, respectively, for a total of 9.9 parts by mass per 100 parts by mass of activated carbon, and 220.0 parts by mass of water was added per 100 parts by mass of activated carbon.

[0160] Manufacturing Example 2 A molded product having a pH of 5.87 in aqueous suspension measured in accordance with JIS K 1474 (2014) was obtained in the same manner as in Production Example 1, except that activated carbon having a pH of 4.50 in aqueous suspension measured in accordance with JIS K 1474 (2014) was used.

[0161] Manufacturing Example 3 A molded product having a pH of 6.58 in aqueous suspension measured in accordance with JIS K 1474 (2014) was obtained in the same manner as in Production Example 1, except that activated carbon having a pH of 7.35 in aqueous suspension measured in accordance with JIS K 1474 (2014) was used.

[0162] Manufacturing Example 4 A molded product having a pH of 9.13 in an aqueous suspension measured in accordance with JIS K 1474 (2014) was obtained in the same manner as in Production Example 1, except that activated carbon having a pH of 9.54 in an aqueous suspension measured in accordance with JIS K 1474 (2014) was used.

[0163] Production Example 5 50 g of sodium hydroxide was dissolved in 250 g of distilled water, 100 g of activated carbon was added, and the mixture was dried at 120 °C for 3 hours to produce activated carbon with a pH of 11.27 in aqueous suspension, as measured according to JIS K 1474 (2014). This activated carbon was mixed with an organic binder and water, and extruded using an extruder (Dalton Co., Ltd., Disc Pellet F5) with a 2.2 mm hole diameter and 15 mm thickness die. The pellets were then refined using a Marumerizer (Dalton, Q-400T) to obtain a molded product with a material composition similar to the activated carbon-containing layer of the heat storage material-integrated activated carbon. The pH of the resulting molded product was measured according to JIS K 1474 (2014) and found to be 10.43 in aqueous suspension. There is a positive correlation between the hardness of the molded product and the hardness of the heat storage material-integrated activated carbon. The organic binders selected were carboxymethylcellulose sodium salt (F30MC manufactured by Nippon Paper Industries Co., Ltd.), Epocross WS-700 (an oxazoline group-containing water-soluble polymer manufactured by Nippon Shokubai Co., Ltd.), and ADEKA Resin (an aqueous epoxy resin EM-0180 manufactured by ADEKA Corporation), with solid contents of 6.8 parts by mass, 1.2 parts by mass, and 1.9 parts by mass, respectively, for a total of 9.9 parts by mass per 100 parts by mass of activated carbon, and 215.0 parts by mass of water was added per 100 parts by mass of activated carbon.

[0164] Comparative Manufacturing Example 1 A molded product having a pH of 2.88 in aqueous suspension measured in accordance with JIS K 1474 (2014) was obtained in the same manner as in Production Example 1, except that activated carbon having a pH of 2.92 in aqueous suspension measured in accordance with JIS K 1474 (2014) was used.

[0165] Test Example 5 The ASTM hardness was measured with reference to ASTM-D5228. The results are shown in Table 4. In Table 4, the pH of each molded product is indicated as A if it is 4.5 or higher, and B if it is less than 4.5.

[0166] [Table 4]

[0167] By comparing Production Examples 1 to 5 and Comparative Production Example 1, it can be seen that the base carbon can be used regardless of its pH as long as it has a pH of 3 or higher, and that the pH of the activated carbon-containing layer of the heat storage material-integrated activated carbon is preferably A (4.5 or higher).

Claims

1. A latent heat storage material-integrated activated carbon containing a latent heat storage material having microcapsules encapsulating a phase change substance that absorbs and releases latent heat depending on temperature, and activated carbon, The latent heat storage material has a surface of the microcapsules coated with an organic binder-containing layer containing a thermosetting organic binder A, The surface of the latent heat storage material is coated with an activated carbon-containing layer containing activated carbon and an organic binder B, and The activated carbon integrated with a latent heat storage material, wherein the pH of an aqueous suspension of the activated carbon-containing layer is 4.5 or more, as measured in accordance with JIS K 1474 (2014).

2. 2. The activated carbon integrated with latent heat storage material according to claim 1, wherein the average particle diameter of the microcapsules is 0.1 to 500 μm.

3. 3. The activated carbon integrated with latent heat storage material according to claim 1, wherein the activated carbon has an average particle size of 1 μm to 10 mm.

4. The latent heat storage material-integrated activated carbon according to any one of claims 1 to 3, wherein the average cross-sectional diameter of the latent heat storage material is 0.75 to 1.80 mm.

5. The content of the latent heat storage material is 7 to 30 mass%, based on 100 mass% of the total amount of the latent heat storage material-integrated activated carbon. The latent heat storage material-integrated activated carbon according to any one of claims 1 to 4.

6. The activated carbon integrated with a latent heat storage material according to any one of claims 1 to 5, wherein the calorific value is 10 to 100 J / g.

7. The activated carbon integrated with a latent heat storage material according to any one of claims 1 to 6, having an ASTM hardness of 45% or more.

8. A method for producing a latent heat storage material-integrated activated carbon according to any one of claims 1 to 7, (1) A step of mixing the microcapsules with the thermosetting organic binder A (2) a step of coating the microcapsule composition obtained in step (1) with the thermosetting organic binder A and heat-treating the coated microcapsule composition to obtain the latent heat storage material; (3) A step of mixing the latent heat storage material obtained in step (2) with a composition containing the activated carbon and organic binder B and granulating the mixture. A manufacturing method comprising:

9. The method according to claim 8, wherein the step (1) is a step of mixing the microcapsules and the thermosetting organic binder A, followed by extrusion granulation and subsequent granulation.

10. The method according to claim 8 or 9, wherein in the step (3), the composition containing the activated carbon and the organic binder B further contains a pH adjuster.

11. A canister containing the latent heat storage material-integrated activated carbon according to any one of claims 1 to 7.

12. A canister for an automobile connected to a sealed gasoline tank, which contains the activated carbon integrated with a latent heat storage material according to any one of claims 1 to 7.

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