JPH0665563A - Production of heat storage composition - Google Patents

Abstract

PURPOSE:To obtain a heat storage compsn. scarcely allowing an oily substance to ooze out and excellent in heat resistance by mixing a silane-modified polyolefin, a low-density ethylene-alpha-olefin copolymer, and the oily substance and subjecting the mixture to a specific crosslinking treatment. CONSTITUTION:This compsn. is produced by mixing a silane-modified polyolefin (e.g. a silane-modified polyethylene), an ethylene-alpha-olefin copolymer having a density lower than 0.925g/cm<2> (e.g. an ethylene-propylene copolymer), and an oily substance (e.g. n-paraffin) pref. at higher than the m.p. of the modified polyolefin and subjecting the mixture to such a treatment that only the modified polyolefin is crosslinked, e.g. by holding the mixture in water vapor, water, or moist air. The compsn. is suitable for a heat storage material for a hot curler and for applications where heat resistance at 130 deg.C or higher is required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heat storage composition utilizing latent heat associated with melting and solidification of a substance. The heat storage composition obtained by this production method is particularly useful for applications requiring heat resistance of 130 ° C. or higher, such as a heat storage material for hot curlers.

[0002]

2. Description of the Related Art Various oily substance-supporting bodies in which a liquid oily substance is supported on a substrate to form a solid have been proposed. Among them, in particular, an oily substance carrier in which an oily substance such as paraffin is supported on a substrate resin has been proposed as a heat storage body, and one using ultra-high molecular weight polyethylene as the substrate resin is disclosed in JP-A-59-170180. Japanese Unexamined Patent Publication (Kokai) No. Sho 62-62 uses a high-density polyethylene crosslinked body as a substrate resin.
No. 187782.

This heat storage body (heat storage composition) is a latent heat storage material that utilizes the latent heat required for the phase transition between the solid phase and the liquid phase of an oily substance. Latent heat storage materials utilizing the phase transition between the solid phase and the liquid phase generally have a problem in handling, that is, when the liquid becomes a liquid due to the phase transition, consideration needs to be taken to prevent it from flowing out. Therefore, such a latent heat storage material usually has to be stored in a container made of metal or resin, but the above-mentioned heat storage composition is a substrate resin and an oily material such as paraffin which is a latent heat storage component. Since it is mixed with a substance and is contained in a state where the oily substance is dispersed in the substrate resin to form a solid state, it does not become liquid even when the oily substance is melted and can be handled as a solid. Have.

[0004]

However, the above-described conventional heat storage composition has a problem that the exudation of the oily substance is large. As a heat storage composition which hardly exudes an oily substance, a heat storage composition containing paraffins, hydrocarbon rubber and crystalline polyolefin as main components is disclosed in JP-A-3-66.
Japanese Patent Laid-Open No. 3-66787 discloses a heat storage composition containing a paraffin, a hydrocarbon polymer, a silane compound and an organic peroxide as main components. However, the heat storage composition disclosed in Japanese Unexamined Patent Publication (Kokai) No. 3-66789 liquefies at a temperature equal to or higher than the melting point of the crystalline polyolefin, resulting in poor heat resistance. Further, the heat storage composition disclosed in Japanese Patent Laid-Open No. 3-66787 has a problem in that paraffins, which are heat storage components, are cross-linked and the heat storage amount is reduced.

Therefore, the present invention aims to provide a method capable of obtaining a heat storage composition in which the oily substance is less exuded as compared with the conventional products, is excellent in heat resistance, and has a heat storage amount maintained. To do.

[0006]

In order to solve the above problems, a method for producing a heat storage composition according to the present invention comprises a silane-modified polyolefin and an ethylene-α-olefin copolymer having a density of less than 0.925 g / cm ^3. After mixing with the oily substance, only the silane-modified polyolefin is subjected to a crosslinking treatment.

The silane-modified polyolefin used in the present invention can be obtained, for example, by mixing a polyolefin, a silane compound and a peroxide at a temperature equal to or higher than the melting point of the polyolefin and grafting the silane compound on the polyolefin. The silane compound is not particularly limited, but examples thereof include vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane. As a polyolefin,
Although not particularly limited, for example, polyethylene, ethylene-α-olefin copolymer and the like are desirable. Examples of the ethylene-α-olefin copolymer that can be used as the polyolefin when synthesizing the silane-modified polyolefin include ethylene, propylene, and 1
-Butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like α-olefin copolymerized in a proportion of about several mol%, but,
It is not limited to this.

In the present invention, the ethylene-α-olefin copolymer mixed with the oily substance and the silane-modified polyolefin has a density of less than 0.925 g / cm ³ . Its density is preferably 0.910
g / cm ³ or less, more preferably 0.89 g / cm ³ or less. Examples of the ethylene-α-olefin copolymer include the same ones used when synthesizing the silane-modified polyolefin described above,
It is not limited to that.

The oily substance used in the present invention includes:
A silane-modified polyolefin, especially one having compatibility with an ethylene-α-olefin copolymer is desirable, and its specific examples are not particularly limited, but for example, hydrocarbons (normal paraffin, isoparaffin,
Polyethylene wax and the like), fatty acids and fatty acid esters, and the like. These may use only 1 type and may use 2 or more types together. The oily substance is preferably a crystalline substance. This is because when such an oily substance is used, a heat storage composition having a large heat storage amount can be obtained.

Silane-modified polyolefin and ethylene-α
The mixing ratio of the olefin copolymer and the oily substance is appropriately set according to the application of the heat storage composition and the like, and is not particularly limited. For example, silane-modified polyolefin: 5 to 65 parts by weight ethylene-α-olefin copolymer Polymer: 5 to 65 parts by weight Oily substance: 30 to 90 parts by weight is preferable. However, the total of the silane-modified polyolefin and the ethylene-α-olefin copolymer is 10
Up to 70 parts by weight, and the total of oily substances added to this is 10
0 parts by weight. If the ratio of the ethylene-α-olefin copolymer is less than the above range, the exudation of the oily substance may increase, and if it exceeds the above range, the heat storage amount may be too low. If the ratio of the silane-modified polyolefin is less than the above range, the shape may not be maintained, and if it exceeds the above range, the heat storage amount may be too low.

Silane-modified polyolefin and ethylene-α
-The method of mixing the olefin copolymer and the oily substance is not particularly limited, for example, melt mixing such as a method of kneading with a kneader or the like at a temperature equal to or higher than the melting point of the silane-modified polyolefin. The method and the like are preferable. This is because such a method makes it possible to obtain a uniform mixture. After mixing, it may be molded into a desired shape such as a pellet shape, a strand shape, a film shape, a sheet shape, or a net shape using an extruder or the like, if necessary.

Silane-modified polyolefin and ethylene-α
If necessary, components other than these three components, for example, antioxidants, flame retardants, various inorganic fillers, etc. may be added to the mixture of the olefin copolymer and the oily substance.
In addition, a crosslinking aid such as dibutyltin dilaurate may be added to the above mixture, if necessary, in order to accelerate the crosslinking of the silane-modified polyolefin. The crosslinking aid is
For example, it may be added by a method such as mixing with a silane-modified polyolefin in the form of pellets of a master badge dispersed in polyolefin.

In the present invention, after the silane-modified polyolefin, the ethylene-α-olefin copolymer and the oily substance are mixed, only the silane-modified polyolefin is subjected to a crosslinking treatment. The method of the cross-linking treatment is not particularly limited as long as it is a method in which only the silane-modified polyolefin is cross-linked. For example, a mixture of the silane-modified polyolefin, the ethylene-α-olefin copolymer, and the oily substance is steamed. , A method of maintaining in water or wet air, and the like.

[0014]

In the present invention, the silane-modified polyolefin, the ethylene-α-olefin copolymer having a density of less than 0.925 g / cm ³ and the oily substance are mixed, and then only the silane-modified polyolefin is subjected to a crosslinking treatment. There is.
Then, the use of the ethylene-α-olefin copolymer having a density of less than 0.925 g / cm ³ reduces the exudation of the oily substance. If the density is 0.925
When an ethylene-α-olefin copolymer of g / cm ³ or more is used, the effect of suppressing exudation of the oily substance decreases.

By crosslinking the silane-modified polyolefin, it becomes possible to obtain a heat storage composition having excellent heat resistance which does not liquefy even at a temperature above the melting point of the silane-modified polyolefin. Since the cross-linking is limited to only the silane-modified polyolefin, the cross-linking is efficiently performed and the decomposition of the oily substance by the cross-linking agent and the reduction of the heat storage amount due to the cross-linking are eliminated. If the above-mentioned Japanese Patent Laid-Open No. 3-66787 is used.
When the paraffins, the hydrocarbon polymer, the silane compound and the organic peroxide are mixed as in the heat storage composition disclosed in Japanese Patent Laid-Open Publication No. 2003-242, the silane compound and the organic peroxide are mixed with the paraffins and the hydrocarbon polymer. It disperses in both and decomposes and crosslinks paraffins. For this reason,
The amount of silane compound and organic peroxide required for crosslinking increases, and paraffins are decomposed and crosslinked, so that the amount of heat storage decreases. Other cross-linking methods include a method in which a peroxide, an oily substance, a polyolefin and an ethylene-α-olefin copolymer are melt-mixed to cause a cross-linking reaction at a high temperature.
Even oily substances are decomposed and cross-linked, reducing the amount of heat storage. Further, there is also a method of mixing an oily substance, a polyolefin and an ethylene-α-olefin copolymer, followed by molding, and then irradiating with radiation to crosslink, but in this case as well, decomposition into an oily substance and crosslinking occur, The heat storage amount decreases.

[0016]

EXAMPLES Next, examples of the present invention will be shown together with comparative examples, but the present invention is not limited to the following examples. In the following examples, "parts" means "parts by weight" unless otherwise specified. —Example 1— 10 parts of XF-700A (silane-modified polyethylene, manufactured by Mitsubishi Petrochemical Co., Ltd.) as a silane-modified polyolefin, and Toughmer P068 as an ethylene-α-olefin copolymer.
0 (manufactured by Mitsui Petrochemical Co., Ltd.), 125 parts of paraffin as an oily substance, 70 parts of manufactured by Nippon Seiro Co., Ltd., and 0.5 part of dibutyltin dilaurate as a cross-linking aid are biaxial type. After using a kneading extruder (S1-KRC kneader, manufactured by Kurimoto Iron Works Co., Ltd.) to heat to 150 ° C. and kneading,
It was extruded into a strand having a diameter of 5 mm, cooled and solidified. This molded product is kept in hot water at 100 ° C. for 30 minutes,
A heat storage composition was obtained by crosslinking.

Example 2 In Example 1, a polyethylene wax (Mitsui High Wax 1 was used as the oily substance instead of the paraffin 125 product.
A heat storage composition was prepared in the same manner as in Example 1 except that the same amount of 00P and Mitsui Petrochemical Industry Co., Ltd. were used. -Example 3-A heat storage composition was produced in the same manner as in Example 1 except that butyl stearate was used in the same amount as the oily substance instead of 125 paraffin.

Example 4-A heat storage composition was prepared in the same manner as in Example 1 except that the same amount of capric acid was used instead of 125 paraffin as the oily substance. -Example 5- In Example 1, it carried out similarly to Example 1 except having used VL100 (Sumitomo Chemical Co., Ltd. product) instead of Tufmer P0680 as an ethylene-alpha-olefin copolymer, and the heat storage composition. The thing was made.

-Comparative Example 1-FZ50D (Mitsubishi Petrochemical Co., Ltd.) as high-density polyethylene
10 parts, Tufmer P0680 (manufactured by Mitsui Petrochemical Industry Co., Ltd.) as an ethylene-α-olefin copolymer 20
Part, 125 parts of paraffin as an oily substance (70 parts by Nippon Seiro Co., Ltd.), 0.5 part of dibutyltin dilaurate as a crosslinking aid, and Kayacum Mill D as a peroxide.
(Dicumyl peroxide, manufactured by Kayaku Nouri Co., Ltd.) 2
The parts were heated to 150 ° C. for kneading using a twin-screw kneading extruder (S1-KRC kneader, manufactured by Kurimoto Iron Works Co., Ltd.), and then extruded into a strand having a diameter of 5 mm to be cooled and solidified. This molded product was held in hot water at 100 ° C. for 30 minutes and crosslinked to obtain a heat storage composition.

Comparative Example 2 10 parts of XF-700A (silane-modified polyethylene, manufactured by Mitsubishi Yuka Co., Ltd.) as a silane-modified polyolefin, 20 parts of F15 (manufactured by Tosoh Corp.) as an ethylene-α-olefin copolymer. , 70 parts of 125 paraffin oil (manufactured by Nippon Seiro Co., Ltd.) as an oily substance, and 0.5 part of dibutyltin dilaurate as a cross-linking aid were used in a twin-screw kneading extruder (S1-KRC kneader, Kurimoto Iron Works ( (Manufactured by K.K.) and heated to 150 ° C. for kneading, and then extruded into a strand having a diameter of 5 mm to cool and solidify. 100 this molded product
By holding in hot water at ℃ for 30 minutes and crosslinking,
A heat storage composition was obtained.

-Comparative Example 3-FZ50D (Mitsubishi Petrochemical Co., Ltd.) as high-density polyethylene
10 parts, Tufmer P0680 (manufactured by Mitsui Petrochemical Industry Co., Ltd.) as an ethylene-α-olefin copolymer 20
Part, and 70 parts of paraffin 125 product (manufactured by Nippon Seiro Co., Ltd.) as an oily substance, a twin-screw kneading extruder (S1-K
An RC kneader manufactured by Kurimoto Iron Works Co., Ltd. was used to heat and knead the mixture at 150 ° C., and then the mixture was extruded into a strand having a diameter of 5 mm, cooled and solidified to obtain a heat storage composition.

-Comparative Example 4-FZ50D (Mitsubishi Petrochemical Co., Ltd.) as high-density polyethylene
10 parts, Tufmer P0680 (manufactured by Mitsui Petrochemical Industry Co., Ltd.) as an ethylene-α-olefin copolymer 20
Part, and 70 parts of paraffin 125 product (manufactured by Nippon Seiro Co., Ltd.) as an oily substance, a twin-screw kneading extruder (S1-K
An RC kneader manufactured by Kurimoto Iron Works Co., Ltd. was used to heat and knead the mixture at 150 ° C., and the mixture was extruded into a strand having a diameter of 5 mm to be cooled and solidified. This molded product has an acceleration voltage of 1.5
A heat storage composition was obtained by irradiation with an electron beam of 30 Mrads at MV and a current of 50 μA for crosslinking.

The resins used in Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 1 below, and the oily substances are shown in Table 2 below. Table 1 shows the product number and density (test method: JIS-K67
60) and the type of α-olefin. Table 2 shows the product number, type, chemical structure, melting point and latent heat amount. Regarding the heat storage compositions produced in the above Examples 1 to 5 and Comparative Examples 1 to 4, when the oily substance was 125 paraffin (Examples 1 and 5 and Comparative Examples 1 to 4), the atmosphere of the temperature condition shown in FIG. 1 was used. In the atmosphere of the temperature conditions shown in FIG. 2 when the oily substance is butyl stearate (Example 3) or capric acid (Example 4), and when the oily substance is polyethylene wax (Example 2) 2 in the atmosphere of the temperature conditions shown in 3.
A cold heat test of 00 cycles (1 cycle = 1.6 hours) was performed. After the test, take out the heat storage composition, wipe off the oily substance exuding around the heat storage composition at a temperature equal to or higher than the melting point of the oily substance (= melting point of the oily substance + 20 ° C.), and exude the oily substance from the reduced weight. The rate was measured.

Here, the exudation rate of the oily substance is obtained according to the following relational expression (I). Exudation rate (%) = (weight reduction amount of heat storage composition / initial oily substance content) × 100 (I) The results are shown in Table 3 below.

As shown in Table 3, the density is 0.925 g /
It was confirmed that when an ethylene-α-olefin copolymer having a cm ³ or more was used, the exudation amount of the oily substance was extremely increased (see Comparative Example 2). Next, with respect to the heat storage compositions prepared in Examples 1 to 5 and Comparative Examples 1 to 4, DS
The latent heat quantity was measured using C (differential scanning calorimeter), and the results are shown in Table 3 below.

As shown in Table 3, in Comparative Examples 1 and 4, it was confirmed that the latent heat amount was reduced. Next, the heat storage compositions prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were examined for deformation when left for 1 hour in an air atmosphere at 150 ° C. The results are shown in Table 3 below.

As shown in Table 3, in Examples 1 to 5, Comparative Examples 1 to 2 and Comparative Example 4, there was no deformation, whereas
In Comparative Example 3, the shape could not be maintained and the material melted (liquefied).

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a heat storage composition in which an oily substance as a heat storage component is less exuded, heat resistance is excellent, and a heat storage amount is maintained as compared with a conventional product.

[Brief description of drawings]

FIG. 1 is a graph showing the temperature conditions of a cold heat test for heat storage compositions prepared in Examples 1 and 5 and Comparative Examples 1 to 4.

FIG. 2 is a graph showing temperature conditions of a cold heat test for the heat storage compositions prepared in Examples 3 and 4.

FIG. 3 is a graph showing the temperature conditions of a cold heat test for the heat storage composition prepared in Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuhiro Tsurugi, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Ltd. (72) Inventor, Ryo Sugawara, 1048, Kadoma, Kadoma, Osaka Prefecture

Claims (6)

[Claims] 1. A silane-modified polyolefin having a density of 0.
A method for producing a heat storage composition, wherein an ethylene-α-olefin copolymer having a weight of less than 925 g / cm ³ is mixed with an oily substance, and then only the silane-modified polyolefin is subjected to a crosslinking treatment. 2. The method for producing a heat storage composition according to claim 1, wherein the silane-modified polyolefin is silane-modified polyethylene. 3. A silane-modified polyolefin and ethylene-
The method for producing a heat storage composition according to claim 1 or 2, wherein the α-olefin copolymer and the oily substance are mixed at a temperature equal to or higher than the melting point of the silane-modified polyolefin. 4. The method for producing a heat storage composition according to claim 1, wherein the oily substance is at least one selected from the group consisting of hydrocarbons, fatty acids and fatty acid esters. 5. The method for producing a heat storage composition according to claim 1, wherein the oily substance is a crystalline substance. 6. A silane-modified polyolefin and ethylene-
The heat storage composition according to any one of claims 1 to 5, wherein only the silane-modified polyolefin is subjected to a crosslinking treatment by holding a mixture of an α-olefin copolymer and an oily substance in steam, water or wet air. How to make things.