JP2019218518A - Thermal storage material particle-containing resin pellet, and manufacturing method of thermal storage material particle-containing resin pellet - Google Patents

Abstract

To provide a thermal storage material particle-containing resin pellet high in heat storage amount to blended amount of a thermal storage material particle, and a manufacturing method therefor.SOLUTION: There is provided a thermal storage material particle-containing resin pellet consisting of a thermoplastic resin, and a thermal storage material particle dispersed in the thermoplastic resin and containing a thermal storage material, in which average particle diameter of the thermal storage material particle is 10 to 300 μm, and particle diameter exhibiting a peak of a particle size distribution of the thermal storage material particle is 33% or more and less than 70% of average of maximum particle diameter and minimum particle diameter of the thermal storage material particle [(maximum particle diameter+minimum particle diameter)/2].SELECTED DRAWING: Figure 3

Description

The present invention relates to a heat storage material particle-containing resin pellet and a method for producing the heat storage material particle-containing resin pellet.

Conventionally, a heat storage material such as paraffin has been used as a heat storage material, and latent heat or heat radiation due to phase transition of the heat storage material has been used. The heat storage material stores heat during the phase transition from the solid to the liquid, and releases heat during the phase transition from the liquid to the solid. As a method for repeatedly using the function of heat storage or heat radiation by this phase transition, a method of encapsulating a heat storage material in a capsule having a capsule wall made of an organic resin or an inorganic material such as a melamine resin, a formaldehyde resin, and a phenol resin is known. No. Since the heat storage material is sealed in the capsule, liquid leakage does not occur even if the heat storage material is liquefied.

In addition, in order to obtain a resin product including a heat storage material composed of a capsule in which a heat storage material is enclosed, it is necessary to produce a heat storage material particle-containing resin pellet containing a main resin and heat storage material particles. The resin pellets are molded by injection molding, extrusion molding or the like, and commercialized. These products are used for applications such as food, medicine, and housing.

Patent Literature 1 discloses that a thermoplastic polymer and a microcapsule containing a latent heat storage material (a heat storage material) and having a capsule wall made of a polymer are molded using a multi-screw extruder to obtain a thermoplastic molding composition. Have been. In this step, a technique is disclosed in which a thermoplastic polymer is heated and melted in a screw extruder, and then microcapsules are charged into the screw extruder.

In Patent Document 2, a heated heat storage material obtained by heating a heat storage material in which a heat storage material is encapsulated in a capsule to a thermoplastic resin in a softened state to a temperature higher than a phase transition temperature of the heat storage material is used as a side feeder of an extruder. It is disclosed that a thermoplastic resin composition containing a heat storage material is obtained by charging the mixture from a starting material and mixing.

JP-T-2014-500359 JP 2017-149821 A

In the techniques described in Patent Documents 1 and 2, a thermoplastic resin in a state of being heated and melted in an extruder is heated from a side feeder to a temperature equal to or higher than a phase transition temperature of capsule-type heat storage material particles or a heat storage material at room temperature. The capsule-type heat storage material particles are charged and mixed, and a thermoplastic resin composition containing the heat storage material particles is obtained by extrusion molding.

When charging the heat storage material particles at room temperature from the side feeder, the heat storage material contained in the heat storage material particles undergoes a phase transition, thereby depriving the melted thermoplastic resin of heat and decreasing the viscosity of the thermoplastic resin. The capsule-type heat storage material particles cannot be uniformly mixed, and during extrusion molding, a cut occurs at a portion where the capsule-type heat storage material particles are agglomerated. there were.

Also, when the capsule-type heat storage material particles heated to a temperature equal to or higher than the phase transition temperature of the heat storage material are injected from the side feeder, although the moldability is improved, the heat storage amount of the obtained thermoplastic resin composition containing the heat storage material particles is improved. Was sometimes lower than a design value estimated from the blending amount of the heat storage material particles.

The present invention has been made to solve the above problems, and has as its object to provide a thermoplastic resin pellet containing heat storage material particles and a method for producing a thermoplastic resin pellet containing heat storage material particles.

The heat storage material particle-containing resin pellet of the present invention for achieving the above object,
A thermoplastic resin,
Dispersed in the thermoplastic resin, comprising heat storage material particles containing a heat storage material,
The average particle diameter of the heat storage material particles is 10 to 300 μm,
33% or more and 70% or more of the average value of the maximum particle size and the minimum particle size of the heat storage material particles [(maximum particle size + minimum particle size) / 2], wherein the particle size indicating the peak of the particle size distribution of the heat storage material particles. Less than.

The heat storage material particles contained in the heat storage material particle-containing resin pellet of the present invention have an average particle size of 10 to 300 μm.
In addition, the particle diameter showing the peak of the particle size distribution of the heat storage material particles (hereinafter also referred to as peak particle diameter) is the average value of the maximum particle diameter and the minimum particle diameter of the heat storage material particles [(maximum particle diameter + minimum particle diameter) / 2] of 33% or more and less than 70% indicates that the peak particle diameter is closer to the minimum particle diameter side with respect to the average value of the maximum particle diameter and the minimum particle diameter.
This reflects that many heat storage material particles having a small particle diameter are present.
If there are many heat storage material particles having a small particle diameter, the gap between the heat storage material particles having a large particle diameter can be filled with the heat storage material particles having a small particle diameter. It becomes a thermoplastic resin pellet containing heat storage material particles having a high heat storage amount per unit volume.

The particle diameter of the heat storage material particles contained in the heat storage material particle-containing resin pellets is determined by taking a photograph using a laser microscope (for example, Keyence Corporation product number; shape measurement laser microscope VK-X210, etc.), and taking an image of the photograph. The diameter of the particles that can be distinguished from the heat storage material particles is measured by image analysis software.
Since the cross section of the heat storage material particles seen in the image is not necessarily a cross section including the diameter, the diameter (apparent diameter) obtained from the image does not represent the true diameter of the heat storage material particles. Since the apparent diameter is 0.25π times the true diameter on average, when converting the diameter, the true diameter is obtained using this value as a correction coefficient, and the true diameter is calculated as the particle size of the heat storage material particles. Diameter.
The average particle size and particle size distribution of the heat storage material particles can be obtained by statistically processing the obtained heat storage material particles.
The average particle size of the heat storage material particles is an arithmetic average of the particle sizes of the heat storage material particles.

In obtaining a particle size distribution by statistical processing, a histogram in which the number of classes is determined according to the number of measured particles is created. The rank is determined by the square root selection. The square root k of the measured number n of particles is the class number. If the measured number n of particles is about 1200 to 1500, the class number k is 35 to 39 classes.
According to the determined class number k, the class intervals are determined so that the difference obtained by converting the particle diameter into a logarithm becomes a constant value. The maximum value of the particle diameter in each class is taken as the value of the horizontal axis as a representative value of the particle diameter in that class, and the number of particles contained in each class (expressed as the frequency (%) in the measured particles) is the value on the vertical axis. Is plotted on a particle size distribution graph.

In the heat storage material particle-containing resin pellet of the present invention, the heat storage material particles are preferably formed of a capsule in which the heat storage material is sealed.
When the heat storage material is encapsulated in the capsule, there is no possibility that the heat storage material leaks from the heat storage material particles, and the durability is excellent.

In the heat storage material particle-containing resin pellet of the present invention, the heat storage material particles are preferably heat storage material particles in which the heat storage material is filled in a porous body made of an inorganic material.

The method for producing a heat storage material particle-containing resin pellet of the present invention is a mixing step of mixing a thermoplastic resin and heat storage material particles containing a heat storage material to obtain a mixture of the thermoplastic resin and the heat storage material particles,
A mixture charging step of charging the mixture comprising the thermoplastic resin and the heat storage material particles to an extruder,
A kneading step of heating and kneading the mixture of the thermoplastic resin and the heat storage material particles at a temperature equal to or higher than the melting temperature of the thermoplastic resin,
And a molding step of extruding the kneaded product comprising the thermoplastic resin and the heat storage material particles with an extruder to obtain resin pellets.

In the method for producing a resin pellet containing heat storage material particles of the present invention, a mixture of a thermoplastic resin and heat storage material particles is prepared by mixing a thermoplastic resin and heat storage material particles, and the mixture is charged into an extruder.
In the extruder, the thermoplastic resin and the heat storage material particles contained in the mixture of the thermoplastic resin and the heat storage material particles are heated at a temperature equal to or higher than the melting temperature of the thermoplastic resin, kneaded under the same heat history, and extruded. Molded.
According to this method, unlike the methods described in Patent Documents 1 and 2, the heat storage material particles having a low temperature are not mixed with the molten thermoplastic resin, and the molten thermoplastic resin is used as the heat storage material. No heat is taken away by the particles. Therefore, the viscosity of the molten thermoplastic resin is low, the molten state becomes uniform, and uniform molding is performed in the molding step.

If uniform molding is not performed in the molding step, a part of the heat storage material particles will be damaged, and it is estimated that the heat storage amount of the heat storage material particle-containing resin pellets decreases.
In the method for producing resin pellets containing heat storage material particles of the present invention, the heat storage material particles are suppressed from being damaged because the molding is performed uniformly in the forming step. And, in the manufactured heat storage material particle-containing resin pellets, the heat storage material particles having a large particle diameter and the heat storage material particles having a small particle diameter are present without being broken together, so that the filling rate of the heat storage material particles is improved, A heat storage material particle-containing resin pellet having a large heat storage amount per unit volume is obtained.

In the method for producing a heat storage material particle-containing resin pellet of the present invention, the temperature of the thermoplastic resin and the heat storage material particles at the time of the mixture charging step is equal to or higher than the phase transition temperature of the heat storage material in the heat storage material particles. Is preferred.

If the temperature of the heat storage material particles is equal to or higher than the phase transition temperature of the heat storage material at the time of injection into the extruder, the heat storage material contained in the heat storage material particles does not further absorb heat due to the phase transition. Absorption of heat is prevented by the phase transition, and heating and kneading in the extruder are smoothly performed.

In the method for producing a heat storage material particle-containing resin pellet of the present invention, the thermoplastic resin used in the mixing step is a powder, and the average particle size of the thermoplastic resin powder is the average particle size of the heat storage material particles. It is preferably at least 1/2 times and not more than 2 times.

By making the thermoplastic resin into a powder, the kneading conditions in kneading in the extruder can be relaxed. Therefore, breakage of the heat storage material particles due to kneading is suppressed.
Further, setting the average particle diameter of the thermoplastic resin powder to １ ／ times or more and twice or less of the average particle diameter of the heat storage material particles is such that the thermoplastic resin powder and the heat storage material particles have the same particle size. Since the particle diameters of both powders are substantially uniform, both can be easily kneaded, so that even if the kneading conditions in the extruder are relaxed, a suitable kneading can be performed. It is preferred.

FIG. 1 is an example of a cross-sectional micrograph of the resin pellet containing heat storage material particles of the present invention produced in Example 1 described below. FIG. 2 is an example of a cross-sectional micrograph of a heat storage material particle-containing resin pellet not included in the present invention, which was produced in Comparative Example 1 shown below. FIG. 3 is a diagram illustrating the particle size distribution of the heat storage material particle-containing resin pellets manufactured in Example 1 and the heat storage material particle-containing resin pellets manufactured in Comparative Example 1 described below. FIG. 4 is a cross-sectional view schematically showing an example of a state of extrusion molding in the method for producing a resin pellet containing heat storage material particles of the present invention. FIG. 5A is a perspective view schematically illustrating an example of a heat storage structure manufactured using the heat storage material particle-containing resin pellets of the present invention. FIG. 5B is a cross-sectional view taken along line AA of FIG.

(Detailed description of the invention)
Hereinafter, the method for producing the heat storage material particle-containing resin pellet and the heat storage material particle-containing resin pellet of the present invention will be specifically described. However, the present invention is not limited to the following configuration, and can be appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more of the individual desirable configurations of the present invention described below is also the present invention.

The heat storage material particle-containing resin pellet of the present invention,
A thermoplastic resin,
Dispersed in the thermoplastic resin, comprising heat storage material particles containing a heat storage material,
The average particle diameter of the heat storage material particles is 10 to 300 μm,
33% or more and 70% or more of the average value of the maximum particle size and the minimum particle size of the heat storage material particles [(maximum particle size + minimum particle size) / 2], wherein the particle size indicating the peak of the particle size distribution of the heat storage material particles. Less than.

The heat storage material particle-containing resin pellet includes a thermoplastic resin and heat storage material particles.
Examples of the thermoplastic resin include AS resin, ABS resin, polyethylene resin, polyester resin (polyetherester elastomer, etc.), polypropylene resin, ethylene-propylene copolymer, polyvinylidene chloride resin, polyamide resin, acetal resin, polycarbonate resin, and polyphenylene. Examples include a sulfide resin, a polyetherimide resin, an aromatic polyetherketone resin, a polysulfone resin, a fluorine resin (eg, polyvinylidene fluoride), a polyamideimide resin, and an acrylic resin. Among these, it is preferable to use a polypropylene resin, a polyethylene resin, a polyester resin, or the like in consideration of heat resistance.

The heat storage material particle-containing resin pellets of the present invention are characterized by the average particle size and the particle size distribution of the heat storage material particles.
FIG. 1 is an example of a cross-sectional micrograph of the resin pellet containing heat storage material particles of the present invention produced in Example 1 described below.
FIG. 2 is an example of a cross-sectional micrograph of a heat storage material particle-containing resin pellet not included in the present invention, which was produced in Comparative Example 1 shown below.
FIG. 3 is a diagram showing the particle size distribution of the heat storage material particle-containing resin pellets manufactured in Example 1 and the heat storage material particle-containing resin pellets manufactured in Comparative Example 1 described below.
The average particle size and particle size distribution of the heat storage material particles contained in the heat storage material particle-containing resin pellets will be described with reference to the laser microscope photographs of FIGS. 1 and 2 and further with reference to FIG.

When observing FIGS. 1 and 2, the heat storage material particles having a small particle diameter are often observed in FIG. 1 and the heat storage material particles having a large particle diameter are frequently observed in FIG. It can be seen that the number is smaller than that of. Further, the particle diameter of the largest heat storage material particle is substantially the same between FIG. 1 and FIG.
FIG. 3 shows the particle size distribution of the heat storage material particles in the two resin pellets.
One is the particle size distribution of the heat storage material particles in the resin pellets obtained in Example 1 (corresponding to the solid line), and the other is the particle size distribution of the heat storage material particles in the resin pellets obtained in Comparative Example 1 ( (The dotted line corresponds). In the particle size distribution of the heat storage material particles in these two resin pellets, both the maximum particle diameter is 300 μm and the minimum particle diameter is 10 μm.
Therefore, the average value of the maximum particle diameter and the minimum particle diameter of the heat storage material particles [(maximum particle diameter + minimum particle diameter) / 2] is 155 μm.
On the other hand, the peak particle diameter of the particle size distribution of the heat storage material particles is 85 μm in Example 1 and 115 μm in Comparative Example 1.
That is, the heat storage material particles contained in the heat storage material particle-containing resin pellets of the present invention are mainly located on the side where the particle size distribution is smaller than 100 μm in particle size, and the heat storage material particle-containing resin not included in the present invention It can be said that the heat storage material particles contained in the pellets are mainly located on the side where the particle size distribution is larger than 100 μm in particle size.

The above characteristics in the particle size distribution of the heat storage material particles, when indicated by the position of the peak particle diameter with respect to the average value of the maximum particle size and the minimum particle size of the heat storage material particles, the heat storage material particle-containing resin pellets of the present invention, the peak particles It is described that the diameter is 33% or more and less than 70% of the average value.
Here, in FIG. 3, the average value of the maximum particle diameter and the minimum particle diameter of the heat storage material particles is 155 μm, the peak particle diameter at which the average value of the peak particle diameter is 33% is 46.5 μm, and the average of the peak particle diameter is 46.5 μm. The peak particle diameter at which the value becomes 70% is 108.5 μm.
Since the peak particle diameter of the heat storage material particles of Example 1 was 85 μm, it was 55% of the average value, and the peak particle diameter was in the range of 33% or more and less than 70% of the average value, and the heat storage material of Comparative Example 1 was used. Since the peak particle diameter of the particles is 115 μm, it is 74% of the average value, and the peak particle diameter is out of the range of 33% or more and less than 70% of the average value.

FIG. 3 shows, for reference, the particle size distribution of the heat storage material particles used as the raw material in the production of the resin pellets containing the heat storage material particles in Example 1 and Comparative Example 1.
In Example 1, the particle size distribution is almost the same as that of the heat storage material particles of the raw material. On the other hand, in Comparative Example 1, the entire particle size distribution is shifted to a side where the particle diameter is larger than that of the heat storage material particles of the raw material.
From this, in Comparative Example 1, since the heat storage material particles having a small particle diameter are reduced with respect to the particle size distribution of the heat storage material particles as a raw material, the heat storage material particles having a small particle diameter are damaged during manufacturing. It is estimated that there is. In Example 1, it is estimated that the heat storage material particles of the raw material remain without being damaged.

The average particle size of the heat storage material particles is 10 to 300 μm.
When the average particle diameter of the heat storage material particles is 10 μm or more, the amount of the heat storage material contained in the heat storage material particles is sufficient, and the heat exchange efficiency of the resin product with respect to the amount of the heat storage material particles is sufficiently high.
When the average particle diameter of the heat storage material particles is 300 μm or less, the moldability at the time of forming the heat storage material particle-containing resin pellets is improved.
The average particle size of the heat storage material particles is preferably 20 to 200 μm.

The heat storage material particles include a heat storage material.
The heat storage material is preferably at least one selected from the group consisting of paraffin, sodium sulfate hydrate, sodium acetate hydrate, calcium chloride hydrate, erythritol and sodium thiosulfate. Since these substances can easily control the melting point, they can be suitably used as heat storage substances. Furthermore, it is preferable to use paraffin as the heat storage material in terms of the degree of freedom of design for use and use.
The phase transition temperature of the heat storage material is preferably from -5 to 80C. Further, the phase transition temperature is more preferably from 5 to 75 ° C, even more preferably from 30 to 70 ° C.

The type of the heat storage material is not limited, but in the phase transition of the heat storage material in the above temperature range, the change from liquid to solid or from solid to liquid is controlled because the change in volume is small. A heat storage material having such properties is preferably used.
As the heat storage materials, only those having the same phase transition temperature may be used, or a plurality of types of heat storage materials having different phase transition temperatures may be mixed and used. When two or more types of heat storage materials having different phase transition temperatures are used, these heat storage materials may be included in the same heat storage material particles, or may be included in different heat storage material particles for each heat storage material. Good.

As an embodiment in which the heat storage material particles include the heat storage material, when the heat storage material particles are capsules in which the heat storage material is enclosed (hereinafter, also referred to as capsule-type heat storage material particles), the heat storage material particles are made of a porous material made of an inorganic material. In the case where the heat storage material particles are filled with a heat storage material in the body (hereinafter, also referred to as porous heat storage material particles), there are two embodiments.

When the heat storage material particles are capsule type heat storage material particles in which a heat storage material is encapsulated, the constituent material of the capsule is an organic material or an inorganic material.
Further, it is preferable to use a material that is durable with respect to the phase transition temperature of the heat storage substance as a constituent material of the capsule.
As the organic material, a thermoplastic elastomer such as a diene resin or an olefin thermoplastic elastomer can be used, but the following types of thermosetting resins are preferable. When the organic material is a thermosetting resin, it is possible to prevent the capsule wall from being broken by heat during heat exchange.
The thermosetting resin is preferably at least one type of thermosetting resin selected from the group consisting of melamine resin, urea resin, polyurethane, polyurea, polyamide and polyacrylamide.
The inorganic material is preferably at least one selected from the group consisting of silica, alumina and carbon.

When the heat storage material particles are heat storage material particles in which a heat storage material is filled in a porous body made of an inorganic material, the inorganic material as the porous body is at least one selected from the group consisting of silica, alumina, and carbon. It is preferable that
These materials are preferable because they have a small dimensional change with respect to heat and do not hinder heat transfer due to heat storage or heat radiation due to phase transition of the heat storage material even when used in a temperature region of 50 ° C. or higher.
Further, when a resin product obtained by molding a resin pellet containing heat storage material particles is used in an environment where heat resistance is required, dimensional change due to heat hardly occurs, which is preferable. Therefore, the generation of stress in the resin product is suppressed, the product is less likely to crack or deform, and the life of the product can be extended.

Commercial names of the heat storage material particles include a product name: Thermo Memory manufactured by Mitsubishi Paper Mills Co., Ltd .; a microcapsule for heat storage manufactured by Miki Riken Co., Ltd .; a product name: Riken Redin; What is done can be used.

Further, other additives may be contained in the heat storage material particles.
The additive contained in the heat storage material particles may be contained in the heat storage material. As the additives contained in the heat storage material particles, additives that can be used for resin pellets, such as stabilizers and colorants, can be used.
Although the content of the additive contained in the heat storage material particles is not particularly limited, an amount necessary for obtaining the heat storage material particles or an amount necessary for exerting the function as the heat storage material can be used.

The shape of the heat storage material particles is preferably spherical, elliptical, polyhedral, or the like.
When the shape of the heat storage material particles is spherical or elliptical sphere, there is no apex, and no stress due to the corners of the heat storage material particles is generated.

The content of the heat storage material particles is preferably 30 to 80% by weight based on the total weight of the resin pellets containing the heat storage material particles.
When the content of the heat storage material particles is within the above range, the effect of heat storage or heat radiation by the heat storage material particles in the formed product can be suitably obtained when the heat storage material particle-containing resin pellets are molded to obtain a molded product. Further, the molded article is prevented from becoming too hard or brittle.
More preferably, the content of the heat storage material particles in the heat storage material particle-containing resin pellets is 35 to 70% by weight based on the total weight of the heat storage material particle-containing resin pellets.
In addition, the total weight of the heat storage material particle-containing resin pellets is the total amount of the thermoplastic resin, the heat storage material particles, and other additives.

It is preferable that the resin pellet containing the heat storage material particles contains a dispersant.
The dispersant is used to disperse the heat storage material particles in the thermoplastic resin when preparing the heat storage material particle-containing resin pellets. By using a dispersant, fluidity during molding can be increased, and moldability at low temperatures can be particularly improved.
In particular, when the thermoplastic resin is a polyester resin and the heat storage material particles are porous heat storage material particles, the fluidity may be reduced, but the use of a dispersant can enhance the fluidity. preferable.

The dispersant is preferably at least one selected from the group consisting of an ethylene copolymer and a carboxylic anhydride copolymer.
The above dispersant is particularly suitable for increasing the fluidity of the thermoplastic resin containing the heat storage material particles during molding.
Further, in the heat storage material particle-containing resin pellet containing the dispersant or the resin product molded from the heat storage material particle-containing resin pellet, when the heat storage material leaks from the heat storage material particle, the heat storage material is absorbed by the dispersant. Can be done. Therefore, the shape as a resin product molded from the heat storage material particle-containing resin pellet or the heat storage material particle-containing resin pellet can be maintained. As a result, the strength of the heat storage material particle-containing resin pellet and the strength of the resin product molded from the heat storage material particle-containing resin pellet can be maintained.
Examples of the ethylene copolymer include an ethylene propylene copolymer, an ethylene-vinyl acetate copolymer, and an ethylene-methacrylic acid copolymer.
Examples of the carboxylic anhydride copolymer include a maleic anhydride-grafted polyolefin resin, a maleic anhydride polyethylene resin, and a maleic anhydride high-density polyethylene resin.

The heat storage material particle-containing resin pellets may contain other additives. The additive herein is an additive contained in the thermoplastic resin.
As the additives contained in the thermoplastic resin, additives applicable to resin pellet applications can be used, and examples thereof include stabilizers, redox agents, molding aids, decomposition inhibitors, lubricants , A release agent, a coloring agent such as a pigment, a plasticizer, and the like.

Further, the heat storage material particle-containing resin pellets may further include a filler having a higher thermal conductivity than the thermal conductivity of the thermoplastic resin. When the heat storage material particle-containing resin pellets include such a filler having thermal conductivity, the heat transfer speed between the thermoplastic resin and the heat storage material particles can be improved. Further, since the heat storage material particles contain the heat storage material, as a result, the speed of heat transfer to the heat storage material or the speed of heat transfer from the heat storage material can be improved. Therefore, heat exchange can be performed efficiently.
When the heat storage material particle-containing resin pellet contains a filler, the content is preferably 10 to 30% by weight based on the weight of the heat storage material particle-containing resin pellet.
The filler is not particularly limited, for example, an inorganic filler composed of glass, silica, wollastonite, aluminum hydroxide, kaolin, titanium oxide, alumina, mica, talc, carbon, potassium titanate, and copper. For example, a metal filler or the like composed of such as can be used. The filler may be in the form of particles, fibers, or whiskers.
In addition, the metal filler may be one obtained by plating the surface of an inorganic filler or a resin particle with metal. From the viewpoint of improving the thermal conductivity of the resin product, glass fibers and carbon fibers are desirable.

The shape of the resin pellet containing the heat storage material particles is not particularly limited, and the size is not particularly limited. By setting the shape and size of the resin pellet used for the extrusion of the ordinary resin, a resin product can be obtained using an extruder used for the extrusion of the ordinary resin.
Among them, the shape of the heat storage material particle-containing resin pellet is preferably a columnar shape, a spherical shape (including an oval shape), a prismatic shape, and more preferably a cylindrical shape.
When the shape of the resin pellet containing the heat storage material particles is cylindrical, it is suitable for molding the resin.
When the shape of the heat storage material particle-containing resin pellets is cylindrical, it is preferable that the resin pellets have a height of 0.1 to 20 mm and a diameter of 0.1 to 20 mm.

The method for producing a heat storage material particle-containing resin pellet of the present invention is a mixing step of mixing a thermoplastic resin and heat storage material particles containing a heat storage material to obtain a mixture of the thermoplastic resin and the heat storage material particles,
A mixture charging step of charging the mixture comprising the thermoplastic resin and the heat storage material particles to an extruder,
A kneading step of heating and kneading the mixture of the thermoplastic resin and the heat storage material particles at a temperature equal to or higher than the melting temperature of the thermoplastic resin,
And a molding step of extruding the kneaded product comprising the thermoplastic resin and the heat storage material particles with an extruder to obtain resin pellets.

(Drying process)
First, although it is an optional step, in the method for producing resin pellets containing heat storage material particles of the present invention, it is preferable to perform a drying step for reducing the amount of moisture contained in the heat storage material particles before the mixing step.
When the amount of water contained in the heat storage material particles is reduced, aggregation of the heat storage material particles due to water is suppressed, and a mixture in which the thermoplastic resin and the heat storage material particles are uniformly mixed can be obtained.
In the drying step, it is preferable to perform drying at 50 to 80 ° C. for 1 to 5 hours.
Further, it is preferable to perform drying so that the moisture absorption of the heat storage material particles is 5% or less.

(Mixing process)
In the mixing step, the thermoplastic resin and the heat storage material particles are mixed before being fed into the extruder, to obtain a mixture composed of the thermoplastic resin and the heat storage material particles.

The mixing of the thermoplastic resin and the heat storage material particles may be performed by manual mixing and stirring, or may be performed by a mixing machine such as a mixing tank, a mixer, a V-type mixer, or a W-type mixer. The mixing time and mixing conditions are not particularly limited.
In the mixing step, the above-mentioned dispersant and other additives may be added in addition to the thermoplastic resin and the heat storage material particles.

In the mixing step, it is preferable to obtain a mixture of the thermoplastic resin and the heat storage material particles by mixing the thermoplastic resin powder and the heat storage material particles.
Usually, thermoplastic resins are often obtained in the form of pellets. Thermoplastics in the form of pellets are larger in size than the heat storage material particles.
In the extrusion molding of a normal thermoplastic resin containing no heat storage material particles, the pellets of the thermoplastic resin are put into an extruder, and the pellets of the thermoplastic resin are reduced by shearing force of a screw in kneading in the extruder. I do.
When a shearing force is applied to the mixture of the thermoplastic resin and the heat storage material particles to reduce the thermoplastic resin pellets in the extruder, the heat storage material particles are damaged when the thermoplastic resin pellets are reduced. Could be
Therefore, if a thermoplastic resin powder is prepared in advance and mixed with the heat storage material particles to obtain a mixture of the thermoplastic resin and the heat storage material particles, the size of the thermoplastic resin is reduced in the extruder. Therefore, the kneading conditions in the extruder can be reduced. As a result, breakage of the heat storage material particles due to kneading in the extruder is prevented.
In the present specification, kneading a mixture of a thermoplastic resin and heat storage material particles in an extruder using a screw or the like is referred to as “kneading”. This is a different concept from "mixing" in which the heat storage material particles are mixed.

When a thermoplastic resin powder is used, it is preferable to use a thermoplastic resin that has been pulverized to a predetermined particle size and sieved.
At this time, the shape of the thermoplastic resin powder is not particularly limited, such as a spherical shape, a cylindrical shape, and a polygonal pillar shape, but a spherical shape is more preferable.
The particle size of the thermoplastic resin is not particularly limited, but is preferably 10 to 1000 μm in sieve diameter. More preferably, it is 20 to 400 μm.
In the present specification, “powder of thermoplastic resin” means a thermoplastic resin having a sieve diameter of 1000 μm or less (particle diameter capable of passing through a sieve having a mesh size of 1000 μm).

The average particle diameter of the thermoplastic resin powder is preferably at least 倍 times and not more than twice the average particle diameter of the heat storage material particles.
The above range means that the thermoplastic resin powder and the heat storage material particles have the same particle diameter, and in this case, the thermoplastic resin particles and the heat storage material particles are easily mixed, Even if the kneading conditions in the extruder are relaxed, preferable kneading can be performed, which is preferable.

Further, the heat storage material particles may be heated beforehand so as to have a phase transition temperature of the heat storage material or higher before mixing with the thermoplastic resin.
When the heat storage material has a temperature equal to or higher than the phase transition temperature, when mixed with the thermoplastic resin, heat absorption due to the phase transition of the heat storage material is prevented from affecting the mixing state.

Alternatively, the thermoplastic resin may be heated to a temperature equal to or higher than its melting temperature in a molten state, and the melted thermoplastic resin and the heat storage material particles may be heated and mixed at the melting temperature or higher. .

(Mixture charging step)
In the mixture charging step, a mixture including the thermoplastic resin and the heat storage material particles is charged into an extruder.
In the mixture charging step, the heat storage material particles and the thermoplastic resin are charged together in an extruder in a mixed state.
In this way, in the extruder, the thermoplastic resin and the heat storage material particles are heated at a temperature equal to or higher than the melting temperature of the thermoplastic resin, kneaded under the same heat history, and extruded.
That is, unlike the methods described in Patent Documents 1 and 2, the heat storage material particles having a low temperature are not mixed with the molten thermoplastic resin later, and the molten thermoplastic resin is formed by the heat storage material particles. You will not be deprived of heat. Therefore, the viscosity of the molten thermoplastic resin is low, the molten state becomes uniform, and uniform molding is performed in the molding step.

Further, it is preferable that the temperature of the heat storage material particles be equal to or higher than the phase transition temperature of the heat storage material at the time of the mixture charging step.
If the temperature of the heat storage material particles is equal to or higher than the phase transition temperature of the heat storage material at the time of injection into the extruder, the heat storage material contained in the heat storage material particles does not further absorb heat due to the phase transition. Absorption of heat due to phase transition is suppressed, and heating and kneading in the extruder are smoothly performed.

Also, before being put into the extrusion molding machine, the mixture of the thermoplastic resin and the heat storage material particles was heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin to be in a molten state, and the heat storage material particles were melted. A mixture with a thermoplastic resin may be charged into an extruder.
If the thermoplastic resin is molten at this point, the kneading conditions in the extruder can be further relaxed.
For example, it is preferable that the thermoplastic resin is melted by heating to a temperature higher by at least 10 ° C. than the melting temperature of the thermoplastic resin.

(Kneading and molding process)
As the extruder, one having a supply port, a screw, a heater, and a die can be used. The mixture comprising the thermoplastic resin and the heat storage material particles is fed into the extruder through a supply port.
The extruder is provided with a heater, and the thermoplastic resin and the heat storage material particles can be heated in the extruder above the melting temperature of the thermoplastic resin to melt the thermoplastic resin. Then, a mixture comprising the thermoplastic resin and the heat storage material particles is kneaded using a screw or the like.
In addition, the temperature of the mixture of the thermoplastic resin and the heat storage material particles is maintained at a temperature equal to or higher than the melting temperature of the thermoplastic resin so that the molten thermoplastic resin does not solidify again.

When the mixture to be injected into the extruder is a mixture of thermoplastic resin powder and heat storage material particles, that is, when the mixture is injected into the extruder in a state where the thermoplastic resin is not melted, The extruder moves toward the die while the thermoplastic resin powder and the heat storage material particles are both heated. When the temperature of the mixture of the thermoplastic resin and the heat storage material particles becomes equal to or higher than the melting temperature of the thermoplastic resin, the phase change of the heat storage material is completed and the temperature of the heat storage material starts rising, and the thermoplastic resin is melted and melted with the heat storage material particles. As a mixture with the thermoplastic resin obtained, the mixture moves while being kneaded in the extruder, and the kneaded product composed of the thermoplastic resin and the heat storage material particles is extruded from a die and extruded to produce a heat storage material particle-containing thermoplastic resin pellet. You.
In the above process, the thermoplastic resin and the heat storage material particles contained in the mixture are extruded by receiving the same heat history, so that the heat storage material particles having a low temperature are not mixed with the molten thermoplastic resin, and The heated thermoplastic resin does not lose heat due to the phase transition or heat capacity of the heat storage material of the heat storage material particles. Therefore, the viscosity of the molten thermoplastic resin does not decrease, and uniform molding is performed in the molding step.

When the mixture of the thermoplastic resin and the heat storage material particles has been heated in advance to the melting temperature of the thermoplastic resin or higher and is a mixture of the molten thermoplastic resin and the heat storage material particles, the heat storage material in the heat storage material particles The phase transition is completed, and the mixture moves while being kneaded in the extruder as a mixture of the heat storage material particles having the same temperature and the molten thermoplastic resin. And extruded to produce resin pellets containing heat storage material particles.
The heating by the heater of the extruder is performed to maintain the temperature of the mixture of the thermoplastic resin and the heat storage material particles at or above the melting temperature of the thermoplastic resin so that the molten thermoplastic resin does not solidify again.
Also in the above process, since the thermoplastic resin and the heat storage material particles contained in the mixture are extruded by receiving the same heat history, the heat storage material particles having a low temperature with respect to the molten thermoplastic resin are not mixed. In addition, the molten thermoplastic resin does not lose heat due to the phase transition or heat capacity of the heat storage material of the heat storage material particles. Therefore, uniform molding is performed in the molding step.

In this molding step, the kneaded material composed of the thermoplastic resin and the heat storage material particles is kneaded by the shearing force of the screw and extruded from the die.
At this time, the number of revolutions of the screw of the extruder, the extrusion speed of the kneaded product composed of the thermoplastic resin and the heat storage material particles, and the like are not particularly limited, but the kneading conditions can be set to be more relaxed than in the past.
For example, the rotation speed of the screw can be set to 50 to 400 rpm, and the discharge rate can be set to 5 to 30 kg / hr.

Hereinafter, an example of an extruder that can be used in an embodiment of the method for producing resin pellets containing heat storage material particles of the present invention will be described with reference to the drawings.
FIG. 4 is a cross-sectional view schematically showing an example of a state of extrusion molding in the method for producing a resin pellet containing heat storage material particles of the present invention.
The extruder 100 shown in FIG. 4 includes a cylinder 110, a screw 120, a supply port 130, a heater 140, and a die 150.
The mixture 200 is a mixture of the powdered thermoplastic resin 210 and the heat storage material particles 220, and is supplied to the supply port 130 in a state where the thermoplastic resin 210 and the heat storage material particles 220 are mixed.
The mixture 200 charged into the extruder 100 is kneaded by the screw 120 and moves toward the die 150 while being heated by the heater 140.
When the temperature of the mixture 200 becomes equal to or higher than the melting temperature of the thermoplastic resin 210, the thermoplastic resin 210 is melted, becomes the thermoplastic resin 210 ′ fused with the heat storage material particles 220, and is formed into a kneaded product kneaded by a screw. The heat storage material particles are extruded from the die 150 as a strand 230 and extruded to produce resin pellets containing heat storage material particles.

By using the heat storage material particle-containing resin pellets of the present invention, a heat storage structure containing heat storage material particles can be manufactured. The shape of the heat storage structure is not particularly limited, and is preferably a shape that can be formed by extrusion.
For example, it is preferable to use a heat storage structure having a flow path through which the fluid flows. By flowing the fluid through this flow path, heat exchange can be performed between the fluid and the heat storage structure.
The fluid is not particularly limited, and may be a liquid or a gas, but is preferably a gas. Further, the fluid is more preferably air.

It is preferable that the heat storage structure has a plurality of flow paths.
When the heat storage structure has a plurality of flow paths, the degree of contact between the fluid and the heat storage structure can be increased. Since the heat exchange efficiency between the fluid and the structure depends on the degree of contact between the fluid and the structure, heat exchange can be performed efficiently if the heat storage structure has a plurality of flow paths.

The shape of the heat storage structure is preferably a honeycomb shape in which a plurality of flow paths are arranged in parallel in the longitudinal direction with a partition wall therebetween.
When the shape of the heat storage structure is a honeycomb shape, the degree of freedom of use and use is increased by combining the shapes of the flow passages. Further, the strength of the heat storage structure can be sufficiently increased. Further, the degree of contact between the fluid and the heat storage structure can be increased.

In the honeycomb-shaped heat storage structure, the thickness of the partition wall is not particularly limited, but is preferably 50 to 5000 μm, and more preferably 500 to 3000 μm.
When the thickness of the partition is 50 μm or more, the partition is sufficiently thick, so that the strength of the heat storage structure is sufficiently increased. Further, since the heat storage material particles contained in the partition walls can be in a sufficient amount, the heat exchange efficiency is improved.
When the thickness of the partition is 5000 μm or less, the degree of contact between the fluid and the heat storage structure can be sufficiently increased. Further, heat is easily transmitted to the inside of the partition. Therefore, the heat exchange efficiency is improved.

In the honeycomb-shaped heat storage structure, the density of the flow path is not particularly limited, but is preferably 10 to 1000 cells / square inch, and 30 to 800 cells / square in a cross section perpendicular to the longitudinal direction of the heat storage structure. More preferably, inches.
When the density of the flow path is 10 pieces / square inch or more, the degree of contact between the fluid and the heat storage structure increases. Therefore, the heat exchange efficiency is improved.
When the density of the flow path is 1,000 or less per square inch, the partition walls have a sufficient thickness, and the heat storage structure has a sufficient strength.

In the honeycomb-shaped heat storage structure, the shape of the flow path in a cross section perpendicular to the longitudinal direction is not particularly limited, and may be, for example, a triangle, a square, a pentagon, a hexagon, or an octagon.

An example of a heat storage structure manufactured using the heat storage material particle-containing resin pellets of the present invention will be described with reference to the drawings.
FIG. 5A is a perspective view schematically illustrating an example of a heat storage structure manufactured using the heat storage material particle-containing resin pellets of the present invention. FIG. 5B is a cross-sectional view taken along line AA of FIG.
The heat storage structure 1 shown in FIGS. 5A and 5B is a structure used for heat exchange with the fluid F.
The member 10 forming the heat storage structure 1 is made of heat storage material particles and a thermoplastic resin.
The heat storage structure 1 includes a plurality of inflow ports 21 through which the fluid F flows, a plurality of flow paths 22 through which the fluid F flowing from the inflow port 21 passes, and a plurality of flow paths through which the fluid F passing through the flow path 22 flows out. The heat storage structure 1 has an outlet 23, and the shape of the heat storage structure 1 is a honeycomb shape in which a plurality of flow paths 22 are arranged side by side in a longitudinal direction across a partition wall 24. The flow of the fluid F is indicated by an arrow in FIG.

(Example)
Hereinafter, examples that specifically disclose the present invention will be described. Note that the present invention is not limited to only these examples.

In the following Examples and Comparative Examples, the following were used as thermoplastic resins, heat storage materials, and additives.
(1) Thermoplastic resin Thermoplastic resin A Material: Thermoplastic polypropylene resin (Novatech PP MG05ES manufactured by Nippon Polypropylene Corporation: melting temperature 150 ° C)
Thermoplastic resin B Material: Thermoplastic polyetherester elastomer (Hytrel (registered trademark) manufactured by Du Pont-Toray Co., Ltd. Melting temperature: 160 ° C)
(2) Thermal storage material particles Thermal storage material particles A Capsule wall: melamine resin Thermal storage material: paraffin (manufactured by Mitsubishi Paper Mills, product number: Thermomemory FP-9, phase transition temperature 9 ° C)
Thermal storage material particles B Capsule wall: Melamine resin Thermal storage material: Paraffin (manufactured by Mitsubishi Paper Mills, product number: Thermo Memory FP-27, phase transition temperature 27 ° C)
Thermal storage material particles C Porous body: Silica Thermal storage material: Paraffin (manufactured by Miki Riken Kogyo Co., Ltd., product number: RIKEN Resin LA-66, phase transition temperature 66 ° C)
(3) Additive colorant: black colorant

[Example 1]
(Mixing process)
The thermoplastic resin A was freeze-pulverized to prepare 8 kg of powder having an average particle diameter of 100 μm and 12 kg of heat storage material particles A (average particle diameter: 100 μm). The thermoplastic resin A and the heat storage material particles A were placed in a resin container (30 liters) and stirred for 20 minutes to obtain a mixture containing the thermoplastic resin and the heat storage material particles.
The mixture containing the thermoplastic resin and the heat storage material particles was heated at 80 ° C. for 4 hours using a hot air drier.

(Mixture charging step)
A mixture containing the thermoplastic resin A and the heat storage material particles A was charged into a supply port of an extruder.

(Kneading and molding process)
The cylinder is heated to a temperature higher by 10 to 30 ° C. than the melting temperature of the thermoplastic resin A, and while the thermoplastic resin is being melted, the mixture containing the thermoplastic resin and the heat storage material particles is moved and kneaded in an extruder to knead the mixture. Extrusion molding was performed from a die to produce resin pellets containing heat storage material particles.
The kneading conditions in the extrusion molding were as follows: the rotation number of the screw was 150 rpm, and the discharge rate was 20 kg / hr.

[Examples 2 to 9]
In the process of Example 1, the type and weight of the thermoplastic resin and the type and weight of the heat storage material particles were changed as shown in Table 1, to produce resin pellets containing heat storage material particles.
In Examples 7 to 9 using thermoplastic resin B, the temperature of the cylinder was set to 10 to 20 ° C. higher than the melting temperature of thermoplastic resin B.

[Example 10]
In the mixing step of Example 1, 0.3 kg of the coloring agent was added, and the blending amount of the thermoplastic resin A was reduced by that amount to 7.7 kg to obtain a mixture containing the thermoplastic resin and the heat storage material particles.
Other steps were the same as in Example 1 to produce a heat storage material particle-containing resin pellet.

[Comparative Example 1]
8 kg of unmilled pellets of thermoplastic resin A (5 mm × 4 mm × 3 mm ellipsoid) and 12 kg of heat storage material particles A (average particle diameter: 100 μm) were prepared.
The heat storage material particles A were preliminarily heated at a temperature equal to or higher than the phase transition temperature of the heat storage material so that the heat storage material was in a phase-transitioned state.
The pellets of the thermoplastic resin A were put into the supply port of the extruder.

The temperature of the cylinder was set to 10 to 30 ° C. higher than the melting temperature of the thermoplastic resin A, and the heat storage material particles A were charged from the side feeder while moving the inside of the extruder while melting the thermoplastic resin. It was confirmed that the temperature of the heat storage material particles A at the time of charging was in a phase-transformed state.
The kneaded product thus mixed and kneaded was extruded from a die to produce a heat storage material particle-containing resin pellet.
The kneading conditions in the extrusion molding were as follows: the rotation number of the screw was 150 rpm, and the discharge rate was 20 kg / hr.
Table 1 shows the types and amounts of the thermoplastic resin, the heat storage material particles, and the additives of the respective Examples and Comparative Examples. The content ratio of the heat storage material particles in the resin pellet containing the heat storage material particles is also shown.

(Evaluation)
[Measurement of average particle size and particle size distribution of heat storage material particles]
Using a laser microscope (manufactured by Keyence, product number; shape measuring laser microscope VK-X210), the objective lens 10 times (magnification on a 15-type monitor 200) the resin pellet containing the heat storage material particles obtained in each of the examples and the comparative examples. X), a photograph was taken, and the diameter of the particles that could be distinguished from the heat storage material particles in the image was measured by image analysis software. The average particle size and particle size distribution of the heat storage material particles were obtained by statistically processing the particle size of each of the obtained heat storage material particles.
In each example, the average particle diameter of the heat storage material particles was in the range of 10 to 300 μm.
Further, the peak particle diameter was in the range of 33% or more and less than 70% of the average value of the maximum particle diameter and the minimum particle diameter of the heat storage material particles [(maximum particle diameter + minimum particle diameter) / 2].
In Comparative Example 1, the peak particle diameter is outside the range of 33% or more and less than 70% of the average value of the maximum particle diameter and the minimum particle diameter of the heat storage material particles [(maximum particle diameter + minimum particle diameter) / 2]. Was.
As representative examples, cross-sectional micrographs of the heat storage material particle-containing resin pellets of Example 1 and Comparative Example 1 are shown in FIGS. 1 and 2, respectively. FIG. 3 collectively shows the particle size distributions of the heat storage material particle-containing resin pellets of Example 1 and Comparative Example 1.

[Evaluation of continuous molding]
With respect to the heat storage material particle-containing resin pellets obtained in each of the examples and the comparative examples, in each of the examples, it was confirmed that the strands did not break.
In Comparative Example 1, the strand was broken.

[Heat storage measurement]
The heat storage amount of the resin pellet containing the heat storage material particles obtained in each of the examples and the comparative examples was measured by a differential scanning calorimeter. The measuring method is as follows.
Test equipment TIA Instruments Co., Ltd. Part No .: Differential scanning calorimeter PSC2500 pan Using T-Zero aluminum pan Measurement conditions Heating rate 5 ° C / min
Temperature range -20 ° C → 80 ° C (heating)
80 ℃ → -20 ℃ (cooling down)
-20 ℃ → 80 ℃ (heating)
Measurement atmosphere Room temperature Number of measurement samples 3

In each of the examples, the heat storage amount was 90% or more of the theoretical value of the heat storage amount. In Comparative Example 1, however, the sample having the heat storage amount of less than 90% of the theoretical value of the heat storage amount was used. confirmed.
From these results, in each of the examples, it was estimated that the heat storage material particles were not damaged, and in Comparative Example 1, it was estimated that some of the heat storage material particles were damaged.

DESCRIPTION OF SYMBOLS 1 Thermal storage structure 10 Member 21 Inflow port 22 Flow path 23 Outflow port 24 Partition wall 100 Extruder 110 Cylinder 120 Screw 130 Supply port 140 Heater 150 Die 200 Mixture 210 Thermoplastic resin 210 ′ Melted thermoplastic resin 220 Heat storage material Particle 230 strand

Claims (6)

A thermoplastic resin,
Dispersed in the thermoplastic resin, comprising heat storage material particles containing a heat storage material,
The average particle diameter of the heat storage material particles is 10 to 300 μm,
33% or more and 70% of the average value of the maximum particle size and the minimum particle size of the heat storage material particles [(maximum particle size + minimum particle size) / 2], wherein the particle size indicating the peak of the particle size distribution of the heat storage material particles is A resin pellet containing heat storage material particles. The heat storage material particle-containing resin pellet according to claim 1, wherein the heat storage material particles comprise a capsule in which the heat storage material is sealed. The heat storage material particle-containing resin pellet according to claim 1, wherein the heat storage material particles are heat storage material particles in which the heat storage material is filled in a porous body made of an inorganic material. A mixing step of mixing a thermoplastic resin and heat storage material particles containing a heat storage material to obtain a mixture of the thermoplastic resin and the heat storage material particles,
A mixture charging step of charging a mixture comprising the thermoplastic resin and the heat storage material particles to an extruder,
A kneading step of kneading the mixture of the thermoplastic resin and the heat storage material particles by heating the mixture to a temperature equal to or higher than the melting temperature of the thermoplastic resin,
A method for producing resin pellets containing heat storage material particles, comprising: performing a molding step of extruding a kneaded product comprising the thermoplastic resin and the heat storage material particles with an extruder to obtain resin pellets. The heat storage material particle-containing resin pellets according to claim 4, wherein the temperature of the thermoplastic resin and the heat storage material particles is set to be equal to or higher than the phase transition temperature of the heat storage material in the heat storage material particles at the time of the mixture charging step. Production method. 5. The thermoplastic resin used in the mixing step is a powder, and the average particle diameter of the thermoplastic resin powder is 倍 to 2 times the average particle diameter of the heat storage material particles. 6. Or the method for producing a resin pellet containing heat storage material particles according to 5.