JP2014125626A - Heat storage sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage sheet excellent in processability, especially capable of making thin walls available for mobile communication terminals.SOLUTION: There is provided a heat storage sheet obtained by impregnating a heat storage material composition containing (A) paraffin of 100 pts.mass and (B) a polymer binder component of 1 to 20 pts.mass, and being solid in a temperature range of 100°C or lower into a fiber base material selected from a synthetic fiber woven fabric, a synthetic fiber nonwoven fabric and paper for resolving the above problem.

Description

  The present invention is a sheet-like molded article impregnated with a specific heat storage material composition, and more specifically, a heat storage sheet, a heat storage pressure-sensitive adhesive sheet, and a heat storage adhesive sheet for preventing failure and operation stop due to heat generation of electronic equipment. The present invention relates to a mobile communication terminal having a built-in electronic device part.

  Conventionally, in order to prevent the surface temperature from malfunctioning or stopping operation due to long-term use of electronic equipment, it has been common to use a heat dissipation material, quickly move the heat from the heating element, and dissipate the heat to the outside using a fan. It is. However, since the mobile communication terminal is small and hermetically sealed, it is difficult to dissipate heat with the heat dissipating material and the fan. Therefore, a heat storage resin molded body has been used as a buffer that absorbs and stores heat transferred from the heating element. As such a heat storage resin molded body, a heat storage resin molded body in which a microcapsule containing a heat storage material is contained in a resin or a fiber base material to prevent the heat storage material from flowing out due to a solid-liquid transition is used. Yes (Patent Documents 1 and 2).

  In the molded product containing the microcapsules encapsulating the heat storage material, when the microcapsules are contained in a high ratio, the viscosity of the resin becomes high and kneading becomes difficult. Since the agglomerates aggregate and settle at an early stage, it may be difficult to form a sheet, and there is a problem of workability.

  As another method for preventing the heat storage material from flowing out due to the solid-liquid transition, a method of blending the heat storage material into the polymer binder has been proposed (Patent Document 3).

  However, in order to increase the heat storage capacity, it is necessary to increase the blending amount of the heat storage material. However, since the strength of the heat storage material composition decreases, there is a problem that it is difficult to reduce the thickness of the sheet. In particular, in recent years, consumers have been demanding further downsizing (thinning) of mobile communication terminals such as mobile phones. Therefore, a thin sheet-shaped heat storage material is considered to be very useful for such electronic devices.

JP 2005-023229 A JP 2001-279582 A Japanese Patent Laid-Open No. 04-072383

  The present invention solves the problems of workability of a heat storage material composition using microcapsules and the thinning of the heat storage material composition in which a heat storage material is blended with a polymer binder, and is used for electronic devices caused by heat generation, particularly for mobile communication terminals. It aims at providing the heat storage material which can be used with a thin form especially in the heat storage material which prevents a failure and a stop.

  As a result of intensive investigations to solve the above problems, the present inventors impregnated the heat storage material composition blended with the polymer binder at a specific ratio into the heat storage material into the fiber base material, so that the workability and thinning are reduced. It was found that it is possible to produce a sheet having a high heat storage material content.

That is, the present invention is as follows.
[1] (A) 1 to 20 parts by mass of (B) polymer binder component with respect to 100 parts by mass of paraffin, and a heat storage material composition that is solid in a temperature range of 100 ° C. or less, synthetic fiber woven fabric, A heat storage sheet formed by impregnating a fiber substrate selected from synthetic nonwoven fabric or paper.
[2] The heat storage sheet according to [1], wherein the fiber base material is selected from paper, and the paper is Japanese paper.
[3] A heat storage pressure-sensitive adhesive sheet obtained by applying a pressure-sensitive adhesive to one side or both sides of the heat storage sheet according to [1] or [2].
[4] A mobile communication terminal obtained by attaching the heat storage adhesive sheet according to [3] to a heat generating portion of an electronic device component.

  The heat storage sheet according to the present invention is excellent in processability and can be easily thinned. For this reason, it is possible to suppress breakdown or stop due to heat generation of an electronic device, particularly a mobile communication terminal such as a mobile phone, and to withstand long-term use.

It is the figure explaining the content of the experiment in the following Example.

  The paraffin (A) used in the present invention is preferably an aliphatic hydrocarbon having a melting point or softening point of 100 ° C. or less, and examples thereof include pentadecane, hexadecane, heptadecane, octadecane, nonadecane, icosane, and the like. It is not limited. You may mix and adjust 2 or more types so that solid-liquid transition may be carried out in the heat_generation | fever temperature vicinity of an apparatus.

  Examples of the polymer binder (B) used in the present invention include, but are not limited to, olefin polymers, thermoplastic elastomers, hydrocarbon rubbers, and the like. Two or more polymer binders may be mixed and used, but those having a melting point or softening point of 110 ° C to 130 ° C are preferred from the viewpoint of processability.

  The blending ratio of (A) paraffin and (B) polymer binder component is 1 to 20 parts by mass of the polymer binder with respect to 100 parts by mass of paraffin. Is more preferable. If the polymer binder component is less than 1 part by mass, the outflow of paraffin (A) that has become liquid due to heat cannot be suppressed, and if it exceeds 20 parts by mass, sufficient heat storage capacity cannot be obtained.

  The fiber base material to be impregnated with (A) paraffin and (B) the polymer binder component is a synthetic woven fabric, a synthetic fiber non-woven fabric or paper, preferably paper is used, and the base material is impregnated with the heat storage material composition. Japanese paper is particularly preferred from the standpoints of quantity, thinning, and flexibility. The Japanese paper used here can be a commercially available Japanese paper.

  Examples of synthetic fibers include polyolefin fibers, polyamide fibers, polyacrylic resins, vinylon resins, vinylidene, polyvinyl chloride, polyester fibers, nylon fibers, polyolefin fibers, benzoates, polyclares, phenol fibers, and the like. In the present invention, a woven or non-woven fabric of these fibers can be used as the fiber base material.

  The method of impregnating the fiber base material with the heat storage material composition may be a known one, and the fiber base material is impregnated with the heat storage material composition which has been melted or softened, and then heated, pressed, heated, or water-cooled. Can be molded.

  The amount of impregnation of the heat storage material composition with respect to the fiber base material is preferably 60 to 99% by weight of the heat storage material composition with respect to 100% by weight of the heat storage sheet, and 80% to 98% by weight from the viewpoint of heat storage performance and thinning. More preferably. If it is less than 60% by mass, a sufficient heat storage capacity cannot be obtained, and thinning becomes difficult.

The heat storage sheet of the present invention can be used by being attached to a heat generating portion of an electronic device component. In particular, it is preferably used for electronic equipment parts of mobile communication terminals where thinning is desired. The mobile communication terminal refers to a terminal having an information processing function such as a portable mobile PC in addition to a mobile phone.
Moreover, as an adhesive for sticking to this heat_generation | fever site | part, if it does not inhibit the effect of this invention, it can be especially used without a restriction | limiting.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, parts and% in the examples mean parts by mass and% by mass, respectively.
[Example 1]
With respect to 100 parts of F paraffin wax (paraffin), 15 parts of a thermoplastic elastomer (binder) and 5 parts of a hydrocarbon wax were heated and kneaded at 130 to 140 ° C. to obtain a heat storage material composition (1). Japanese paper (thickness 0.07 mm) was used as a fiber base material, impregnated with a heat storage material composition melted at 130 to 140 ° C., and a heat storage sheet was formed by water cooling (Product 1 of the present invention). The results are shown in Table 1.

[Comparative Example 1]
100 parts of an olefin polymer was added to 100 parts of the heat storage material composition of the product 1 of the present invention, followed by heating and kneading at 130 to 140 ° C. to obtain a heat storage material composition (2). A heat storage sheet was formed with a calender roll at 130 to 140 ° C. using a polypropylene non-woven fabric as a fiber substrate (Comparative Product 1).
[Comparative Example 2]
Without using a fiber base material, the heat storage composition (1) was melted at 140 ° C., cooled on a tray with water, and a heat storage sheet was formed (Comparative Product 2).

  Flexibility was determined by bending the obtained sheet 180 °, ◯ indicating no cracks or cracks, and × indicating cracks or cracks.

[Example 2]
The heat storage sheet of the product 1 of the present invention was affixed to the exterior of a commercially available smart phone (with an automatic stop function for temperature rise), and a temperature change was measured with a thermocouple when moving images were taken and charged simultaneously. The pasting locations are shown in FIG. 1 and the measurement results are shown in Table 2.
[Comparative Example 3]
The temperature was measured by the same operation as in Example 2 except that the measurement was performed without attaching the heat storage sheet to the locations 1 to 3 in FIG.

  In Comparative Example 3, since the automatic stop function was activated after 32 minutes, the measurement was continued with the function stopped after 30 minutes. From this result, it was confirmed that by using the heat storage sheet according to the present invention, the temperature rise due to the heat generation of the device was suppressed and the operation was stable.

1: Near the camera module 2: Near the battery 3: Near the charging terminal 4: Smartphone

Claims (4)

  (A) The heat storage material composition containing 1-20 parts by mass of the polymer binder component (B) and solid in a temperature range of 100 ° C. or less, synthetic fiber woven fabric, synthetic fiber nonwoven fabric with respect to 100 parts by mass of paraffin Or the heat storage sheet formed by impregnating the fiber base material selected from paper.   The heat storage sheet according to claim 1, wherein the fiber base material is selected from paper, and the paper is Japanese paper.   The heat storage adhesive sheet formed by apply | coating an adhesive to the single side | surface or both surfaces of the heat storage sheet of Claim 1 or 2.   A mobile communication terminal comprising the heat storage adhesive sheet according to claim 3 attached to a heat generating portion of an electronic device component.

Images