JPH0598247A - Method for molding heat storage material - Google Patents

Abstract

PURPOSE:To mold a paraffin-based heat storage material into a desired shape in a short time at a high productivity. CONSTITUTION:A raw material compsn. comprising a paraffin and a hydrocarbon polymer is melt mixed, cooled, formed into particles or a band, and extrusion molded at a temp. at least 5 deg.C higher than the heat storage temp. and at least 5 deg.C lower than the m.p. of the polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage material forming method.

[0002]

2. Description of the Related Art Regarding heat storage materials, various heat storage materials have been developed so far, and one of them has been newly developed by the present inventor (filed on July 27, 1990, Japanese Patent Application No. 2-200916). This heat storage material has extremely excellent heat storage characteristics and can be cast into a mold to be formed into a desired shape, for example, a sheet shape or a plate shape. Therefore, it was difficult to say that the work efficiency was never excellent in the molding process, because it was difficult to cool and the molding took a long time.

[0003]

Therefore, the problem to be solved by the present invention is to carry out the above-mentioned forming step in the heat storage material based on the new heat storage material already developed by the present inventor (hereinafter referred to as the prior application heat storage material). It is to eliminate the difficulties in it. More specifically, in forming a heat storage material based on the heat storage material of the prior application, it is to provide a most preferable forming method for this heat storage material.

[0004]

This problem is solved by melting and mixing a heat storage material raw material composition, particularly preferably a heat storage material raw material composition comprising 100 parts by weight of paraffins and 5 to 30 parts by weight of a hydrocarbon organic polymer. After cooling to a granular or band-like or string-like shape, at least 5 ° C higher than the heat storage temperature
It is solved by extruding at a temperature higher than the melting point of the hydrocarbon-based organic polymer by at least 5 ° C.

[0005]

In the present invention, the heat storage material raw material composition is melt-mixed, and the mixture is cooled to form a granular or strip shape, which is extruded.
The band shape includes a string shape. For this reason, the molding can be performed without adopting the conventional means for molding the molten material of the heat storage material into the mold. Therefore, there are no problems such as the mold being unable to move while being cooled in the mold for a long time or being solidified in the mold. In other words, by cooling the molten mixture as in the present invention and then forming it into a granular form or a strip form, the cooling rate is remarkably improved and the work efficiency is remarkably improved. Next, as a result of studying an extrusion molding method as a molding method, it was found that extrusion molding was possible while the hydrocarbon-based organic polymer component was an abnormally low content of 5 to 30 parts by weight, and the hydrocarbon used. A unique method of extrusion-molding at a temperature lower than the melting point of the organic polymer is found, and the extrusion-molding method of the present invention can be effectively adopted.

The heat storage material raw material composition of the present invention is a binder component composed of paraffins as a heat storage component and preferably 5 to 30 parts by weight of a hydrocarbon organic polymer per 100 parts by weight of the paraffins.

As the paraffins used as the heat storage component, T _max measured according to JIS K 7121 (Plastic transition temperature measuring method) is at a working temperature, that is, room temperature to 100 ° C., preferably room temperature to 80 ° C. Organic compounds in the temperature range are used. However, the room temperature at this time means the lowest temperature that the heat storage material of the present invention encounters during its operation.

Preferred specific examples of paraffins include:
Examples thereof include various paraffins, waxes, waxes, fatty acids such as stearic acid and palmitic acid, and polyethylene glycols, and one of these may be used alone or as a mixture of two or more.

In the hydrocarbon organic polymer used in the present invention, the main chain is basically a hydrocarbon, and other components in the main chain (for example, O, N, Si, halogen, etc.)
One or two or more hydrocarbon-based organic polymers having a content of 10% by weight or less, preferably 5% by weight or less are used. Examples of such hydrocarbon organic polymers are shown below.

(1) Polyolefin polymers: homopolymers of α-olefins such as polymethylene, polyethylene and polypropylene, copolymers of olefins,
Other monomers with α-olefins such as vinyl acetate,
Examples thereof include copolymers with ethyl acrylate, ethyl methacrylate and the like, and these lightly halogenated polymers. It may be amorphous to low crystalline,
It may be crystalline.

(2) Thermoplastic elastomers: Among those known or known as "plastic elastomers" in the fields of rubber and plastics, T _{max of} paraffins used at least at the above room temperature and above. In the temperature range of + 10 ° C., preferably, one having rubber elasticity is used at least at room temperature or higher and in the temperature range of T _max + 20 ° C. Of course, a material that maintains rubber elasticity even at a temperature higher than T _max + 20 ° C can be used.

Specifically, styrene type, olefin type,
Various conventionally known thermoplastic elastomers such as urethane type and ester type can be exemplified.

(3) Hydrocarbon rubbers: natural rubber, styrene-butadiene-copolymer rubber, butyl rubber, isoprene rubber, ethylene-propylene copolymer rubber, acetylene-propylene-diene terpolymer rubber, ethylene −
Examples thereof include vinyl acetate copolymer rubber and ethylene-ethyl acrylate copolymer rubber.

The hydrocarbon-based organic polymer as the binder component may be either crosslinkable or non-crosslinkable, but it is preferable that each has rubber-like properties rather than plastic properties.

In the present invention, the amount of the hydrocarbon organic polymer used is preferably 5 to 30 parts by weight based on 100 parts by weight of paraffins. If the amount is less than 5 parts by weight, the flexibility of the resulting composition tends to be low and the composition tends to be brittle.
Above Tmax, paraffins tend to exude or melt and tend to melt. On the other hand, if the amount exceeds 30 parts by weight, the amount of paraffins used tends to decrease and the heat storage amount tends to decrease in proportion thereto.

When it is desired to crosslink or vulcanize a hydrocarbon-based organic polymer (hereinafter collectively referred to as "crosslinking"), they can be carried out before extrusion molding, during extrusion molding, or after extrusion molding. The latter is common.

As the method of crosslinking, any of generally used chemical crosslinking, silane crosslinking (water crosslinking), irradiation crosslinking and the like can be adopted.

When the heat storage material of the present invention is crosslinked, whichever crosslink method is adopted, the degree of crosslinking is JIS.
1% by weight in terms of gel fraction measured according to C 3005
Above (as a composition), preferably at least 2% by weight. By setting the degree of cross-linking to 1% or more, preferably 2% or more, the temperature of the heat storage material can be T _{max of} paraffins used.
Even in the above case, the shape can be maintained without melting or dropping.

In the present invention, the binder component consisting of a hydrocarbon-based organic polymer is particularly preferably the following A or its crosslinked material or B material. In such a case, the affinity between the paraffins and the binder component is particularly good. The amount of the molecule is 5 to 30 parts by weight) can be included in the hydrocarbon-based organic polymer particles.

A. A combination system of the hydrocarbon rubber of (3) and the polyolefin polymer of (1);

In this case, as the polyolefin-based polymers, homopolymers of polymethylene, polyethylene, polystyrene, etc., copolymers of olefins, copolymers of olefins with other monomers such as vinyl acetate, acrylic acid, methacrylic acid etc. And the like, and these are used in one kind or in two or more kinds, and in particular, the maximum crystal transition temperature (usually corresponding to the melting point) measured by JIS K 7121 (Plastic transition temperature measuring method) is used. Highly crystalline at least 10 ° C. above the T _max of the prepared paraffins, preferably T _max
What is used is at least 20 ° C. higher. This crystalline polyolefin, while being used in combination with a hydrocarbon rubber, has appropriate flexibility and surely achieves shape retention. In addition, it is not brittle and does not crack even when molded, and maintains sufficient holding properties. The mixing ratio of the three components is 100 parts by weight of paraffins, 1 to 20 parts by weight of hydrocarbon rubbers, preferably 5 to 15 parts by weight, 1 to 20 parts by weight of polyolefin polymers, preferably 5 to 15 parts by weight. Is. In this mixed system, the heat storage material may be in a non-crosslinked state, but a suitable method such as a gel fraction of at least 1% by weight, preferably at least 2% by weight, for example, the above-mentioned chemical crosslinking method, water crosslinking method and irradiation crosslinking method is used. In particular, it is preferably crosslinked by the water crosslinking method.

B. (2) Thermoplastic elastomers: Paraffins preferably exhibiting rubber elasticity at least at T _max or less. In this case, at a temperature of T _max or lower, since it has rubber elasticity and can be favorably supported by the thermoplastic elastomer in a state of wrapping the paraffins well, the mixture is easy to handle, crack resistant, and easy to mold. Furthermore, since the above-mentioned elastomer maintains rubber elasticity even at a temperature higher than T _max , the heat storage material of the present invention does not melt or drip.

In the present invention, this composition is first melted and mixed. The melting temperature is at least the melting temperature of paraffins and hydrocarbon organic polymers. As long as the mixing is performed by mechanical means, any of various mixing means may be adopted, and typical examples thereof include stirring, mixing, kneading and the like. The mixing by mechanical means means that the remaining component is at least swollen, preferably dissolved in the melt of at least one component in both the paraffins and the hydrocarbon-based organic polymer, or by the high temperature. , Refers to the act of stirring, mixing, or kneading in a state in which any component to be mixed can be flow-deformed by an external force. For example, a mode in which a hydrocarbon-based organic polymer is dissolved in a melt of paraffins maintained at 100 to 200 ° C, and the resulting high-temperature solution is stirred and mixed, a temperature at which each mixed component is softened, for example, 50 to 250 ° C. In this case, an embodiment in which the kneading and mixing is performed by using an ordinary kneader such as a two-roll, a Banbury mixer, an extruder and a twin-screw kneading extruder is exemplified. It is preferred that the degree of mixing is as sufficient as possible, but generally 1
The mixing is performed for about 150 minutes, and it is judged to be visually uniform.

In the present invention, the above-mentioned molten mixture is cooled to be in the form of granules, strips or strings. There are no particular restrictions on the means for forming the granules or strips, but a typical means is, for example, for granulating, the molten mixture is poured into a sieve or sieve or a container having a large number of holes at the bottom. It is possible to efficiently cool and granulate by a method such as dropping in water. Water should be stirred.

Alternatively, the dissolved mixture may be poured into water to form a random block, and when the surface is solidified, it may be left outdoors, for example, to wait for natural cooling, and then it may be pulverized by a pulverizer to be granulated. .. It is also possible to pelletize the random block with a pelletizer to obtain pelletized granules. Natural cooling does not reduce work efficiency. The granular material obtained in this way is φ0.5 to φ1
The shape does not matter, such as a spherical shape of 0 mm, a square shape of 1 mm to 10 mm square, or a granular shape of random shape passing through holes of φ5 to φ40 mm. In order to form a strip or a string, if the above-mentioned container is moved and dropped into water, a strip or a string is formed, and since the wall thickness is thin, it can be efficiently cooled.

Alternatively, a thin plate may be left as it is. The width of the strip or string thus obtained is 1 mm to 200 m.
m, the thickness is 1 mm to 20 mm, and the width is wide and the thickness is thin, and the band is roughly the same. The granules or strips thus obtained are extruded. At this time, the extrusion molding temperature must be at least 5 ° C. higher than the heat storage temperature and at least 5 ° C. lower than the melting point of the hydrocarbon organic polymer. The heat storage temperature at this time is the T _max . If the temperature of the extrusion molding is not higher than the heat storage temperature by 5 ° C, it cannot be extruded, and if the temperature is 5 ° C lower than the melting point of the hydrocarbon-based organic polymer, the appearance of the extrusion is impaired and the molding is successful. The drawback is that it cannot be done. Extrusion conditions other than the extrusion temperature are not particularly limited, and conventional conditions are appropriately adopted. Particularly, by appropriately changing the shape of the die, a long heat storage material having a desired cross section can be obtained, for example, a rectangular cross section, a circle, a star shape or the like can be obtained.

The heat storage material that has been extruded is appropriately cut or used effectively as it is. For example, when a molded product having a circular or angular cross section is to be obtained, it can be easily manufactured by extrusion molding as in the present invention and appropriately cutting the molded product of a long product obtained. Further, since extrusion molding is possible, a long heat storage material can be formed, and a linear heat storage material or the like using a reinforcing material such as a reinforcing wire can be manufactured very easily. It can also be formed into other pipe-shaped heat storage materials. The linear heat storage material containing the reinforcing wire is extremely useful for a direct heat exchange type heat storage device. By performing extrusion molding in this manner, the heat storage material, which has been difficult to form in the past, can be formed into various shapes.

[0028]

EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples.

[0029]

Examples 1 to 4 A heat storage material raw material composition comprising paraffin and a hydrocarbon-based organic polymer (binder resin) shown in Table 1 was melted at 150 ° C. and mixed with stirring. This is then cooled in water into strips and pelletized (about 3
mm square) was created. These pellets are used for φ30 extruder (L
/ D = 28) was extruded at a predetermined temperature to form a rod-shaped body having a diameter of 6 mm. The extrusion results at this time are shown in Table 1.

However, the binder resin A used in Table 1
B is as follows. Binder resin A: thermoplastic elastomer Binder resin B: 50/50 blend of ethylene propylene copolymer and polyethylene

The temperatures in parentheses for paraffin and binder resin in Table 1 indicate the heat storage temperature and the melting point, respectively. The heat storage temperature at this time is a melting peak temperature measured by JIS K 7121, and the melting point of the binder resin is the same as above.

[0032]

Comparative Examples 1 and 2 The components shown in Table 1 were used and treated in the same manner as in the above Examples to obtain extruded products. The results are also shown in Table 1.

[0033]

[Table 1]

[0034]

According to the method of the present invention, since the heat storage material can be formed by extrusion molding, the heat storage material can be formed extremely efficiently and economically. Since a long heat storage material can be formed, a sheet-like material or a plate-like material having a desired cross section can be easily formed simply by cutting it, and also a linear material containing a reinforcing material (for example, a wire). The heat storage material can also be easily manufactured.

Claims (2)

[Claims] 1. A heat storage material raw material composition comprising paraffins and a hydrocarbon organic polymer is melt-mixed and cooled to form a granular or band-like shape, which is at least 5 ° C. higher than the heat storage temperature and at least the above carbonization. A method for forming a heat storage material, which comprises extruding at a temperature 5 ° C. lower than the melting point of the hydrogen-based organic polymer. 2. The heat storage material raw material composition is paraffin 1
The heat storage material molding method according to claim 1, wherein the heat storage material is composed of 100 parts by weight and 5 to 30 parts by weight of the hydrocarbon organic polymer.