JPH02170886A - Thermal energy storage pellet and production thereof - Google Patents

Abstract

PURPOSE:To obtain thermal energy storage pellets, excellent in wax barrier properties and having good mechanical strength by forming a resin layer for preventing a thermal energy storage material from bleeding on the surfaces of crosslinked polyolefin resin pellets impregnated with the thermal energy storage material. CONSTITUTION:The objective pellets obtained by forming a primer layer on the surfaces of crosslinked polyolefin resin pellets impregnated with a thermal energy storage material and then spray coating the surfaces thereof with a resin emulsion in a state of the afore-mentioned independent suspended pellets to form a resin layer for preventing the thermal energy storage material from bleeding. Furthermore, crystalline long-chain alkylhydrocarbons, crystalline higher fatty acids (esters), etc., are cited as preferred examples of the thermal energy storage material.

Description

[Detailed description of the invention] C Industrial application field] The present invention relates to heat storage pellets and a method for producing the same.

[Conventional technology]

Latent heat storage materials, which have the characteristics of a nearly constant heat radiation temperature and a high heat storage density, are being actively developed for applications in fields such as building materials and greenhouse horticulture. This latent heat storage material can be used as a heat storage tank in its bulk form, encapsulated in a small container, or encapsulated or micro-encapsulated (hereinafter referred to as ``(micro)encapsulation''). Three forms have been proposed: From the point of view of heat exchange efficiency, form (2) is preferable to forms (2) and (2), which have a small surface area per volume.

By the way, heat storage materials made of crystalline long-chain alkyl hydrocarbons, higher fatty acids, higher fatty acid esters, and crystalline organic compounds such as higher aliphatic alcohols do not undergo phase separation as seen in inorganic hydrated salt-based heat storage materials. This is preferable since there are no problems such as overcooling or overcooling. As a (micro)capsule of such a heat storage material, N-thermal pellets made by impregnating crosslinked polyolefin resin pellets with this heat storage material have been proposed (Japanese Unexamined Patent Publication No. 187782/1982). These heat storage pellets can be manufactured more economically than the conventional encapsulation method, ie, the orifice method. Furthermore, even when the heat storage material impregnated in the obtained heat storage pellets is melted, the crosslinked polyolefin resin as a carrier maintains the pellet shape with mechanical strength, making it possible to maintain the shape of the heat storage pellets with mechanical strength. It is excellent in that there is no problem of water flowing out.

However, the heat storage pellets described in the above-mentioned publication are simply impregnated crosslinked polyolefin resin pellets with a heat storage material and support the heat storage material in the resin, so when the melting-solidification cycle is repeated, the heat storage material becomes It turned out that there was a problem with it seeping out from inside.

In particular, when the amount of heat storage material impregnated is high, its seepage is significant.

In order to solve this problem, it is effective to form a seepage-preventing resin layer on the surface of the pellet as a film. Therefore, the inventors have already proposed a heat storage pellet in which a seepage-preventing resin layer is formed on the surface of an impregnated pellet made by impregnating a crosslinked polyolefin resin pellet with a heat storage material (Japanese Patent Application No. 62-294899). In this proposal, the ooze-preventing resin layer is formed, for example, by dissolving an oozing-preventing resin in an organic solvent and coating it, or by coating an emulsion of an oozing-preventing resin.

[Problem to be solved by the invention]

FIG. 2 is a schematic cross-sectional view of an example of a heat storage pellet 11 in which a seepage prevention resin layer 14 is directly formed on the surface of an impregnated pellet 12. According to the inventors' research, it is more economical to form the ooze-preventing resin layer 14 by coating emulsilane, which is an ooze-preventing resin, than to coat the ooze-preventing resin by dissolving it in an organic solvent. It is known to be superior.

However, since the emulsion uses water as a medium, it has poor wettability on a hydrophobic surface such as a polyolefin resin made by swelling a heat storage material made of a crystalline organic compound. According to subsequent research by the inventors, when the size of the resin pellets is small, the poor wettability is not so noticeable, but when the resin pellets are large or have various shapes, the emulsion It has been found that it is difficult to form a seepage-preventing resin layer by directly applying it to resin pellets.

Therefore, the first objective of this invention is to solve this problem and provide a heat storage pellet that prevents the heat storage material from seeping out using an economically advantageous emulsion coating. The second objective is to provide a manufacturing method.

[Means to solve the problem]

In order to solve the first problem, the heat storage pellet according to the invention of claim 1 has a heat storage material seeped out by a resin emulsion through a brimer layer on the surface of a crosslinked polyolefin resin pellet impregnated with a heat storage material. It is assumed that a protective resin layer is formed.

In order to solve the above second problem, the method for manufacturing heat storage pellets according to the invention of claim 2 is such that a brimer layer is formed on the surface of a crosslinked polyolefin resin pellet impregnated with a heat storage material, and the resin pellet is A resin emulsion is spray-painted on the surface of the brimer in an independent floating state to form a layer of heat storage material oozing prevention resin (hereinafter referred to as ``bleeding prevention resin'') on the brimer layer. The method of manufacturing M thermal pellets according to the invention of claim 3 is the manufacturing method of claim 2, in which cross-linked polyolefin resin pellets impregnated with a heat storage material are suspended independently, and then a brimer is spray-painted to form the resin pellets. It is characterized by forming a brimer layer on the surface.

[For production]

By forming a brimer layer in advance on the surface of the crosslinked polyolefin resin pellet impregnated with the heat storage material, the wettability of the resin emulsion is improved regardless of the shape and size of the resin pellet, and the emulsion An anti-bleed resin layer is formed.

When the resin pellets with a primer layer formed on the surface are suspended independently and a resin emulsion is spray-painted on the surface to form a seepage-preventing resin layer on the primer layer, the resin pellets are uniformly or nearly An anti-bleed resin layer having a uniform thickness is formed over the entire pellet surface.

The formation of the primer layer is also carried out by spray painting the primer while independently floating crosslinked polyolefin resin pellets impregnated with the heat storage material, so that the coating equipment can be used in common for resin emulsion coating. Alternatively, a continuous operation from brimer application to resin emulsion coating is possible.

[Example] FIG. 1 schematically represents, in cross section, one example of the N-heat pellet according to the invention of claim 1. As shown in this figure, a seepage prevention resin layer 4 made of a resin emulsion is formed on the surface of an impregnated pellet 2, which is a crosslinked polyolefin resin pellet impregnated with a heat storage material, via a primer layer 3. The primer layer 3 can be made as thin as possible since it is sufficient to improve the wettability of the resin emulsion and there is no need to prevent the heat storage material from seeping out. For this reason, the seepage prevention resin layer 4 due to the resin emulsion
without compromising the economic benefits of forming a

The heat storage material used in this invention is a so-called latent heat type material that stores and radiates heat through a phase change. Examples of this heat storage material include, but are not particularly limited to, crystalline long-chain alkyl hydrocarbons that are compatible with polyolefin resins and have a melting point and freezing point of approximately 5 to 50°C, crystalline higher fatty acids, and crystalline higher fatty acids. Preferred are esters and crystalline organic compounds (hereinafter referred to as "waxes") such as crystalline higher aliphatic alcohols. these are,
Each can be used alone or in a mixture of two or more.

The polyolefin resin used as a carrier for the heat storage material in the present invention is not particularly limited, but as described in JP-A-62187782 etc., polyethylene, polypropylene, polybutene (including polybutylene),
Crystalline polystyrene, poly(4-methyl-pentene-
1) etc. Crosslinking of polyolefin resins can be carried out by known or well-known methods such as electron beam irradiation, T-ray irradiation, peroxide treatment, and silane crosslinking, as described in JP-A-62-187782. can.

The degree of crosslinking of the crosslinked polyolefin resin is such that the gel content (gel residual amount) after xylene extraction is 10 to 90% by weight.
(hereinafter simply referred to as "%" unless otherwise specified), and more preferably 30 to 50%. If the gel content is less than 10%, the impregnated pellets may become soft and sticky (for example, "glutinous") and tend to stick to each other. Furthermore, if the gel content exceeds 90%, wax impregnation may become difficult.

As the polyolefin resin, polyethylene is preferred because of ease of crosslinking, ease of impregnation, and ease of availability.

For impregnation of the heat storage material, for example, the molten heat storage material is heated to a temperature higher than the crystal melting point of the crosslinked polyolefin resin, the crosslinked polyolefin resin pellets are placed therein, and heating and stirring are continued. Although this is carried out by impregnating with water, other methods may also be used.

If you use a heat storage material that has good compatibility with polyolefin resin, such as the wax mentioned above, the heat storage material will be contained in the crosslinked polyolefin resin. +m to swell the pellet and fix it in the resin molecules. After heating and stirring for a desired time, the pellets are taken out from the heat storage material to obtain impregnated pellets. The amount of N-thermal material impregnated varies depending on the degree of crosslinking of the pellet, the impregnation temperature, and time, but it is preferably 40 to 85% based on 100% of the total weight of the crosslinked polyolefin resin pellet and the impregnated N-thermal material. .

The shape of the pellet is generally spherical or cylindrical, but is not limited to these shapes, and may be flat, fibrous, cubic, rectangular, irregular, or the like. The shape of the pellets is preferably a shape without sharp corners in order to make the thickness of the seepage-preventing resin layer uniform and to make coating easier. Although the size of the pellets is not intended to be limited, it is preferable that the maximum size after impregnation is 0.5 to 20 mm.

As the size increases, it becomes difficult to flow the pellets using air currents (for example, air currents) when forming a primer layer or seepage prevention resin layer using a fluid coating method, and pellets smaller than 0.5 mm are difficult to handle. Become.

Impregnated pellets impregnated with a heat storage material are obtained as described above. This impregnated pellet has a function as a heat storage pellet and stores and radiates heat, but there is a problem that the heat storage material seeps into the heat storage material as the melting-solidification cycle is repeated. Particularly, when the amount of impregnation of the heat storage material becomes high, such as 70% or more, the seepage becomes significant. In heat storage pellets, the higher the content of heat storage material, the greater the amount of heat storage and the better the efficiency. Therefore, it is necessary to prevent the heat storage material from seeping out.

In this invention, in order to prevent the heat storage material from seeping out, an economically advantageous resin emulsion is used to form a seepage-preventing resin layer so as to cover the entire surface of the impregnated pellet. Since the wettability of impregnated pellets is poor, a seepage prevention resin layer is formed via a primer layer.

The primer layer is formed using a primer that has good wettability on the surface of the impregnated pellets. The brimer is not particularly limited, but at least one selected from a solution prepared by dissolving a certain type of resin in an organic solvent, a surfactant, and a coupling agent is suitable. Note that the surface of the primer layer naturally has better wettability with the resin emulsion than the surface of the impregnated pellet.

When a liquid obtained by dissolving a certain type of resin in an organic solvent is used as the brimer, the resin is preferably one that is soluble in a volatile organic solvent and has excellent film-forming properties. Examples of such resins include polycarbonate resins, polyurethane resins (including urethane elastomers), methacrylic resins, polyphenylene oxides,
Modified polyphenylene oxide (modified PPE), polysulfone, and nitrile rubber, each alone or a blend of two or more thereof, are useful, but are not limited thereto.

The organic solvent is preferably a solvent that is a good solvent for the resin for the brimer and has a boiling point of 150° C. or lower from the viewpoint of volatility. For example, tetrahydrofuran (THF
), dichloromethane, etc., but are not limited to these.

Further, since the surfactant has a hydrophilic group and a lipophilic group (hydrophobic group) in one molecule, it can be used as a brimer in the present invention. When a brimer consisting of a solution of a surfactant is applied to the surface of the impregnated pellet, the lipophilic groups of the surfactant are oriented toward the pellet surface, and the hydrophilic groups are oriented outward, improving the wettability of the resin emulsion. Surfactants include ionic surfactants, nonionic surfactants, and amphoteric surfactants, and there are many types, and although it is impossible to list them all, there are a number of types of surfactants that can be used. Typical examples that can be performed are shown in Table 1.

The brimer is, for example, a surfactant of 0°01 to
It is used in the form of a 10% aqueous solution or a solution in an organic solvent such as benzene, trichloroethylene (for example, Toagosei Kagaku Kogyo Co., Ltd.'s trademark Trichlene), carbon tetrachloride, isopropanol, ethanol, or the like. These solvents may be used alone or in the form of a mixed solvent of two or more.

Examples of coupling agents used in the brimer include silane coupling agents and titanium coupling agents used for surface treatment of inorganic materials. These may be used alone or in combination of two or more.

For example, the silane coupling agent has the general formula % formula % (
), and the titanium-based coupling agent is, for example, one whose general formula is ROT i -R' (bl), where R is hydrogen, methyl, ethyl RL represents a C1-C6 (substituted) alkyl group, vinyl group, epoxy group, methacrylic group, amino group, mercapto group, etc. In formula (b), three R
' can be the same, two can be the same and one can be different,
All three may be separate.

The silane camping agent represented by the above formula (a) is not particularly limited, but includes T-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane,
γ-methacryloxypropyltrimethoxysilane, β-
(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Aminopropyltriethoxysilane, N-β-(aminoethyl)-r-aminopropyltrimethoxysilane, γ
-ureidopropyltriethoxysilane, N-β-(aminoethyl)-β-aminopropylmethyldimethoxysilane, and the like.

The titanium-based coupling agent represented by the above formula (b1) is not particularly limited, but examples include isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraisopropyl bis(dioctyl phosphate), and phyto) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(di-tridecyl) phosphite titanate,
Bis(dioctylpyrophosphate) oxyacetate titanate, tris(dioctylpyrophosphate) ethylene nathanate, and the like.

The coupling agent is dissolved in an organic solvent such as acetone, ethyl acetate, or toluene to a concentration of 1 to 20%, and used as a brimer.

As a method for applying the brimer, it is preferable to use a fluid coating method, as in the case of coating the seepage prevention resin layer. This is advantageous because the coating apparatus can be used in common for coating the brimer and coating the resin emulsion, or it is possible to perform continuous operation from coating the brimer to resin emulsion silane coating. However, the method for applying the brimer may include, but is not limited to, a dipping method in which the impregnated pellets are soaked in a container containing the brimer, or a roller method using a roller impregnated with the brimer. The thickness of the coating layer is not particularly limited, but as long as it can improve wettability with the resin emulsion, it is desirable to coat it as thinly as possible economically, for example, from 0.5 to 0.5. The brimer layer does not need to cover the entire surface of the impregnated pellet, but only partially, as long as it can improve the wettability with the resin emulsion. It may be.

After forming a brimer layer on the surface of the impregnated pellet, a seepage prevention resin layer is formed using a resin emulsion over the entire surface of the impregnated pellet via the brimer layer. The seepage prevention resin layer does not need to expand or contract following the expansion or contraction of the impregnated pellets, and may be separated from the impregnated pellets.

The resin of the resin emulsion must (a) be capable of forming a continuous coating film without pinholes on the surface of the crosslinked polyolefin resin pellets impregnated with the heat storage material (having film formability), and (2) use the above wax as the heat storage material. When used, since the heat storage material has non-polar long-chain alkyl groups as its entire or main component, it must be a polar resin with excellent wax barrier properties that prevent the impregnated heat storage material from seeping out. (C1) It has the mechanical strength to withstand the expansion and contraction of the pellets due to solidification and melting of the heat storage material due to temperature changes, and to withstand the impact and scratches caused by collisions between pellets or between pellets and surrounding objects during pellet handling. to have,
is preferred.

The so-called fluid coating method is useful as a method for independently forming such a resin film on each heat storage pellet. A roller method of coating using a roller or the like may be used.

Emulsion resins are generally not composed of a single monomer, but rather a skeletal monomer (which accounts for the majority of the polymer components and determines major physical properties such as Young's modulus and water resistance).
, adhesion monomers (seven monomers with groups that contribute to adhesion such as carboxyl groups and amino groups), cross-linking monomers (seven monomers with two or more vinyl groups, which form a cross-linking polymer inside the particle through polymerization) ), reactive monomers (during polymerization,
There is almost no reaction while the emulsion is stored, but it cross-links when treated by heating after film formation), a stabilizing monomer (It is an aqueous hexamer, and copolymerizes to stabilize the emulsion. Emulsions with desired performance are designed by combining these seven factors. Furthermore, pigments, dispersants, thickeners, and other additives are generally added to make this emulsion into a paint. The skeleton monomer itself
In many cases, various heptamers are copolymerized.

In this invention, the resin emulsion used for forming the seepage prevention resin layer is preferably, for example, an emulsion having the following resin skeleton, but is not limited thereto. That is, it is an emulsion in which the main component of the resin skeleton is an epoxy resin, urethane resin, acrylic resin, polyester resin, NBR (tolyl rubber), vinylidene chloride resin, or a modified product of each of these resins. These resin emulsions can be used alone, modified, or mixed. Note that the term "emulsion" as used herein includes not only emulsion in its original meaning, but also what is called suspension, disversion, latex, and the like.

The epoxy resin emulsion is an emulsion containing an epoxy resin as a main component, and examples of its synthesis are described in, for example, JP-A-53-47454 and JP-A-54-30249. Commercially available products include, for example, a modified emulsion aqueous dispersion available from Dainippon Ink and Chemicals under the name Pateracol E-3854.

Urethane resin emulsions include, for example, prepolymers obtained from polyethers, polyesters, and diisocyanates, which are optionally emulsified using a surfactant and then chain-extended with a difunctional compound such as 1,2-diamine. There are emulsions whose main components are thermosetting resins made of a mixture of resins, blocked isocyanates, and resins with functional groups (e.g., hydroxyl groups) that are reactive with isocyanate groups. , Japanese Patent Publication No. 50-1
It is described in JP-A No. 4727, JP-A-57-159858, and JP-A-58-132051. As a commercially available product, for example, [
There are water-dispersed urethanes sold under the name ``Bondaic Series'' and ionomer type water-based urethanes sold under the name ``Idran Series.''

As the polyester resin emulsion, for example, an aromatic polyester ionomer aqueous dispersion available from Dainippon Ink and Chemicals under the name "Finetex ES series" is used.

As the acrylic emulsion, for example, various copolymer resin emulsions commercially available from Dainippon Ink and Chemicals under the trade name "Boncoat" can be used.

The NBR emulsion has acrylonitrile-butadiene as its main component, and for example, carboxylated NBR commercially available from Dainippon Ink & Chemicals (2) under the trade name "Luckstar" is used.

As the vinylidene chloride resin emulsion, for example, a vinylidene chloride resin emulsion commercially available from Kenbetsu Kagaku Kogyo under the trade name "Tarehalon Latex" is used.

These emulsions have excellent wax barrier properties because the main component resin is polar. Among the various emulsions mentioned above, it is preferable to select one that is formed into a film at a drying temperature of 50 to 80°C and has excellent mechanical properties.

In order to generally improve film-forming properties, commercially available emulsions may have a dry film that is sticky (tarky) depending on the product number, even if they are of the same type of resin. When such an emulsion is used in the present invention, the resin films may adhere to each other during fluid coating, resulting in the film peeling off from the impregnated pellets or the pellets becoming unable to flow. To prevent this,
It is preferable to select a commercially available emulsion product with a product number such that the dried film does not have tackiness. Alternatively, it is preferred to mix a non-tacky part number emulsion with an emulsion that provides a tacky dry film to reduce tackiness. Needless to say, when mixing, it is preferable to select a combination that provides a stable mixed emulsion.

The thickness of the seepage-preventing resin layer (film) formed by this emulsion coating is not particularly limited;
．． 5-300n is preferable, and 5-200μl is more preferable. If the film is too thin, the mechanical strength of the film will decrease, and even if it is thicker than necessary, the wax barrier properties will not improve, resulting in higher costs and the disadvantage of lowering the volume ratio of the heat storage material. arise.

In this invention, it is preferable to use a fluid coating method for forming the primer layer and/or the anti-bleed resin layer. The fluid coating method uses an air current to coat the object to be coated (for example, impregnated pellets in the case of primer application, impregnated pellets with a primer layer formed on the surface in the case of emulsion application of exudation prevention resin). ) are made to flow independently one by one, and the coating liquid is spray-painted onto the object to be coated in a fluidized state, and the solvent is removed by evaporation, etc., to form a coating layer on the surface of the object to be coated. This is the method. As the coating liquid, a resin emulsion is used to form the seepage-preventing resin layer, and a brimer is used to form the primer layer.

According to the fluid coating method, a coating layer having a uniform or substantially uniform thickness is formed over the entire surface of the object to be coated. As the air flow for volatilizing the solvent, hot air or hot air is used, but is not limited thereto. The temperature of the air stream varies depending on the solvent, but the upper limit is set at a temperature that will prevent the coating liquid from drying and becoming powdery or spidery thread-like before it is applied to the object to be coated, and to prevent the coating liquid from coagulating with each other before it dries. It is preferable to set the lower limit to a temperature that does not occur.

Various types of devices for fluidized coating are commercially available and are easy to obtain, such as Fuji Sangyo's research and development fluidized bed drying, granulation, and coating device AEROMATICAG, and fluidized granulation coating machine. FD-3-5 (3121), Doria Coater, Oyoya Seisakusho fluidized bed granulation coating machine Flow Coater,
Examples include super granulation coating equipment Spiraflow and Kikusui Seisakusho's VG Coco.

In addition, when the impregnated pellet is subjected to fluid coating, if the heat storage material is attached to the surface of the impregnated pellet,
The heat storage material may melt and become sticky due to heating during fluid coating, which may impede the fluidization of the pellets. To prevent this, before fluid coating, the heat storage material adhering to the surface of the impregnated pellets is removed by washing it off, centrifuging it to remove it, or sprinkling the heat storage material with insoluble powder. It is advisable to absorb the heat storage material. In this way, the surface of the impregnated pellet becomes less sticky and becomes easier to flow.

Hereinafter, specific examples and comparative examples of the present invention will be shown, but the present invention is not limited to the following examples. In the following examples and comparative examples, as a crosslinked polyolefin resin,
A silane cross-linked polyethylene resin "Linkron" commercially available from Mitsubishi Yuka ■ was used in the form of micro pellets. As the wax as a heat storage material, in implementation N1, crystalline fatty acid ester "Thermotop 5A" supplied by Jamineka Kogyo Co., Ltd.
J (phase change temperature 5°C), in Example 2.3,
Crystalline fatty acid ester "Thermotop 10" (phase change temperature 10° C.) commercially available from Jiraika Kogyo was used. As a primer, in Example 1-2, a solution prepared by dissolving EPL's polycarbonate resin "Lexan 101-701J in a solvent dichloromethane to a concentration of 10% was used, and in Example 3, a solution prepared by dissolving EPL's polycarbonate resin "Lexan 101-701J" to a concentration of 10% was used, and in Example 3, a solution prepared by dissolving EPL's polycarbonate resin "Lexan 101-701J at a concentration of 10%, Of the resin emulsion of the coating liquid using a 5% aqueous solution of surfactant [Nini Rex Powder F, the modified urethane resin aqueous dispersion is rEXP-382J,
Modified epoxy resin aqueous disverge a'J is rEXP-
385J (both of the above two products are products of Dainippon Ink & Chemicals) were used.

Example 1.2 - Cross-linked polyethylene resin pellets (pellet size: approx. 7
The resin pellets are placed in wax at a temperature (150°C) higher than the melting point of muφ
A 5% impregnated pellet was obtained.

Fuji Sangyo's fluid coating machine (Dria Coater 50)
0), put 3 to 3.5 kg of the impregnated pellets into a coating machine, and first, spray a 10% dichloromethane solution of polycarbonate as a primer to the surface of the fluidized impregnated pellets to a thickness of about 10μ. After the layer was formed, the impregnated pellets with the primer layer formed were brought into a fluid state using the same equipment, and the emulsion listed in Table 2 was spray coated to a thickness of about 100 #m to prevent seepage. A resin layer was formed to obtain heat storage pellets.

- Comparative Example 1 - Direct emulsion coating was applied to the impregnated pellets obtained in Example 1 using the same equipment and under the same conditions without applying the brimer, but no resin film was formed.

Comparative Example 1 The impregnated pellets obtained in Example 2 were directly coated with an emulsion using the same equipment and under the same conditions without being coated with a brimer, but no resin film was formed.

After repeating 200 cycles of solidification (-1O<0>C) and melting (30<0>C) for each of the heat storage pellets obtained in Examples 1 and 2, seepage from the pellets was examined. As a result, no seepage was observed in each of the 100 samples.

Table 2 summarizes the results of Example 1.2 and Comparative Examples 1 and 2.

-Example 3- An impregnated pellet made by impregnating 75% of a heat storage material into a polyethylene resin pellet of approximately 2 mm diameter x 2 mm, with a thickness of 0.5 to 5 mm.
A surfactant was applied as a brimer so that the amount was within 0μ, and a +lJl emulsion was further coated on top of it.

For coating with the primer, the impregnated pellets were immersed in the primer for 20 minutes, transferred to a fluidized coating machine, and dried with ventilation for 5 minutes. A bleed-out prevention resin layer was formed by spray coating until .

When we conducted a seepage test after coating with the emulsion, no seepage of the heat storage material was confirmed (1
θ out of 00 seepage).

In Example 3, polyethylene glycol oleyl ether (Dai Kogyo Seiyaku's E) was used as the primer.
Similar results were obtained using a 1% carbon tetrachloride solution of T140).

- Comparative Example 3 - The same impregnated pellets as made in Example 3 were used. The impregnated pellets were flow coated with the same emulsion used in Example 3 using the same equipment without priming. However, there were large differences in coating conditions, with some cases having good coating and others not. After coating with the emulsion, a seepage test was conducted on 100 randomly selected pellets, and 46 pellets were found to have seepage.

〔Effect of the invention〕

The heat storage pellet according to the invention of claim 1 has a seepage prevention resin layer made of a resin emulsion formed through the brimer layer, so it is economically advantageous and also prevents seepage of the heat storage material. The method for producing the heat storage pellet according to the invention of claim 2, which has a bleed-in prevention resin layer, forms the bleed-in prevention resin layer by fluid coating of a resin emulsion, so that the bleed-in prevention resin has a uniform or almost uniform thickness. Claim 3 wherein a layer is formed.
In the manufacturing method of heat storage pellets according to the invention of claim 2, since the application of the primer is also performed by fluid coating, each coating of the primer and the emulsion can be performed in the same device, and continuous operation is possible. .

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an embodiment of a heat storage pellet according to the invention of claim 1, and FIG. 2 is a schematic sectional view of an example of a conventional N heat pellet. 1... Heat storage pellet 2... Impregnated pellet 3...
・Brimer layer 4... seepage prevention resin layer Figure 1 Figure 2 Agent: Takehiko Matsumoto, patent attorney

Claims (1)

[Scope of Claims] 1. A heat storage pellet in which a resin layer made of a resin emulsion to prevent heat storage material from seeping out is formed on the surface of a crosslinked polyolefin resin pellet impregnated with a heat storage material via a primer layer. 2. A primer layer is formed on the surface of the crosslinked polyolefin resin pellets impregnated with the heat storage material, and a resin emulsion is spray-painted on the surface with the resin pellets floating independently, and then the resin emulsion is spray-painted on the surface of the cross-linked polyolefin resin pellets impregnated with the heat storage material. ,
A method for manufacturing heat storage pellets that forms a resin layer that prevents seepage of heat storage material. 3. The method for producing heat storage pellets according to claim 2, wherein a primer layer is formed on the surface of the resin pellet by spray coating the crosslinked polyolefin resin pellet impregnated with the heat storage material in a state of independent floating.