JP6438740B2 - Method for producing heat storage adhesive sheet - Google Patents

Description

The present invention relates to a method for producing a heat-sensitive adhesive sheet, and more specifically, self-adhesive that can be directly attached to a device or equipment that requires heat countermeasures without providing a separate adhesive layer. It is related with the manufacturing method of the thermal storage adhesive sheet provided with.

  Machines and appliances equipped with electronic components (hereinafter simply referred to as “electronic devices”) have become indispensable in modern life, and mobile phones, smartphones, laptop PCs, tablet PCs can be seen only by looking around. Control for video / audio equipment such as TVs and DVD players, lighting equipment such as LED lamps, home appliances such as refrigerators, air conditioners, washing machines, microwave ovens, automobile parts, and other various devices Power devices such as semiconductor devices and inverters are installed so that it can be said.

  In such an electronic device, the amount of heat generation increases as the CPU is highly integrated, the LED brightness is increased, and a lithium ion battery that easily generates heat is mounted. However, the electronic device itself is required to be downsized. Since the devices are mounted on the substrate with high density, the inside of the casing tends to be hot.

  And if the temperature inside the electronic device becomes high, the processing speed of the CPU will be slowed down due to the effect of heat, or the function of various devices such as LED brightness will be reduced and the life of the device itself will be shortened. There is a risk of causing the user to feel uncomfortable with fever and in some cases causing low-temperature burns.

  In particular, the electrical resistance of semiconductors increases as the temperature rises, and as a result, the rise in temperature induces a thermal runaway that induces further heat generation. In some cases, thermal deformation of plastic parts such as casings or contact with electronic equipment There is also a risk of deformation or discoloration of the contact part of a machine or appliance used (for example, furniture such as a personal computer stand or desk), a strange odor, smoke or fire from an electronic device.

  For this reason, the importance of heat countermeasures for devices that generate such heat is screamed.

  As countermeasures against heat in such electronic equipment, a method of introducing cooling air into the heat generating part with a fan, a method of improving heat dissipation by attaching a heat sink or heat spreader to a heat generating device, a material with good heat conductivity as a heat generating component A method of attaching heat between casings to release heat outside the machine is generally adopted.

  Although it is not related to heat countermeasures for electronic devices, a “heat storage capsule” is formed by encapsulating a heat storage agent that stores heat by phase transition in a resin capsule (microcapsule) with a particle size of several μm to several tens of μm. By adding such a heat storage capsule to a heat medium such as water, it is possible to transport heat efficiently by transporting heat in a state where it is accumulated as latent heat in the heat storage agent. (Claim 1, [0003] column of Patent Document 1).

  In addition, it has also been proposed to apply the above-mentioned heat storage capsule to building materials. As an example, starch, dextrin, and glue are applied to the surface of a sheet body such as paper, wood board, metal plate, synthetic resin sheet, and fiber sheet. In addition, a heat storage sheet for housing interior is also proposed in which a heat storage capsule is attached with a binder such as gelatin and attached to a wall, floor, ceiling or the like (claims 1, [0038] and [0039] of Patent Document 2). , [0042] column).

  Furthermore, as a heat storage sheet similarly provided with a heat storage capsule, a heat storage capsule in which a heat storage agent is enclosed in a capsule having a glass transition point (Tg) of −140 ° C. to −20 ° C. as an outermost layer is manufactured. There has also been proposed a heat storage sheet formed by combining the outermost resin layers of the heat storage capsule into a sheet (claim 1 of Patent Document 3).

Japanese Patent Laid-Open No. 7-26251 JP 2004-270043 A JP 2001-207164 A

(1) Problems in heat countermeasures for electronic devices The above-described method for providing a fan as a heat countermeasure for electronic devices requires a space for housing the fan in the casing of the electronic device. However, it cannot be used as a heat countermeasure for, for example, mobile phones, smartphones, tablet PCs, etc., in which a space for housing the fan cannot be secured.

  In addition, heat countermeasures that improve heat dissipation performance by attaching heat sinks, heat spreaders, and materials with good thermal conductivity are effective in terms of cooling electronic components housed inside, but on the other hand, electronic components Because much of the heat generated in the machine is released to the outside of the machine, it is easy to cause heat damage to machines and equipment used in contact with such electronic devices, and the heat dissipation temperature is increased. For example, the user feels more uncomfortable with the heat released from the electronic device, and the user is at higher risk of low temperature burns.

  On the other hand, in order to protect machines, instruments, and users in contact with electronic equipment from heat, it may be possible to install foamed resin as a heat insulating material inside the casing of the electronic equipment. Even when touching the casing of an electronic device, the user does not feel the heat or can reduce the felt heat.

  However, if such a heat insulating material is attached, the heat generated by the electronic components housed in the casing will be dissipated more in the casing. It will be exposed to high temperatures.

  As described above, in order to prevent the performance degradation and shortening of the life of the electronic component housed in the casing in the electronic device, it is necessary to dissipate the electronic component housed inside and cool it. If the heat generated by electronic components, etc. is released as it is, the machine, equipment, and user that are used in contact with the electronic equipment will be exposed to this heat. It is required to satisfy these two requirements at the same time, and this requirement cannot be satisfied by the existing heat countermeasures described above.

  Therefore, the inventors of the present invention suitably cool the electronic component by storing the heat generated by the electronic component in the heat storage agent as a method of simultaneously satisfying the two conflicting requirements described above, We thought that external devices and users could be protected from heat by suppressing or delaying the release of heat to the outside.

(2) Issues of thermal storage sheet with thermal storage capsule attached to sheet body The thermal storage sheet as the building material introduced earlier as Patent Document 2 is a thermal storage capsule in sheet bodies such as paper, wood board, metal plate, synthetic resin sheet, fiber sheet, etc. When the heat storage sheet is used to take measures against heat of the electronic device, for example, as shown in FIG. 9 (A), the heat storage sheet is mounted on an electronic component or a base on which the electronic component is mounted. It is attached by being sandwiched in a gap between an object to be cooled such as a battery and a casing (a cover portion configured to be detachable in the casing), or the inner surface of the casing (cover portion) as shown in FIG. The heat storage sheet should be affixed to the main body of the casing so that it will come into contact with the object to be cooled. It is thought.

  However, in any of the above configurations, the surface of the heat storage sheet is only in contact with the surface of the object to be cooled, and if the surface of the object to be cooled has irregularities, it is made to follow the surface shape completely. Cannot be contacted in the state.

  For this reason, a non-contact portion that floats is generated between the surface of the heat storage sheet and the object to be cooled. This non-contact portion becomes a resistance to heat conduction, and the heat absorption by the heat storage sheet is reduced.

  In addition, when the heat storage sheet is attached in such a state that it is simply in contact with the object to be cooled, the device that is used while being carried, such as a portable information terminal, may be affected by vibration during carrying. By rubbing, there is a possibility of generating new heat due to friction.

  Furthermore, in the heat storage sheet equipped with the heat storage capsule, heat storage is performed by the phase transition of the heat storage agent enclosed in the heat storage capsule. Therefore, when the phase transition of the heat storage agent is completed, the subsequent heat storage performance is greatly reduced. Will be. Therefore, in order to improve the heat storage performance of the heat storage sheet, it is advantageous to attach more heat storage capsules.

  However, in the conventional heat storage sheet described with reference to Patent Document 2, since the sheet body occupies a large part of the thickness, it is difficult to improve the heat storage performance as a result of restricting the amount of the heat storage capsule attached. .

  In addition, in the configuration in which the surface of the heat storage sheet is only in contact with the inner surface of the casing (cover), the followability with respect to the inner surface of the casing (cover) is poor, and a gap is generated at the joint interface. The problems described above also occur in this part, such as rubbing the inner surface and the heat storage sheet.

  In order to solve such a problem, it is also conceivable to stick the heat storage sheet to both the object to be cooled and the inner surface of the casing by providing an adhesive layer on both surfaces of the heat storage sheet.

  However, the heat storage sheet must be placed in a limited space such as the gap between the object to be cooled and the inner surface of the casing (cover), and the thickness of the entire heat storage sheet is limited by the width of this space. When the pressure-sensitive adhesive layer is separately provided on the front and back surfaces of the sheet, the heat storage performance of the heat storage sheet is further deteriorated because the amount of the pressure-sensitive adhesive layer and the amount of the heat storage capsule attached are reduced.

(3) Problem of heat storage sheet in which heat storage capsule is embedded in pressure-sensitive adhesive As a method for solving the above problem, it is conceivable to manufacture a heat storage pressure-sensitive adhesive sheet having self-adhesive properties in which the heat storage capsule is dispersed in the pressure-sensitive adhesive.

  However, even if it is attempted to add a heat storage capsule having a relatively fine particle size of several μm to several tens of μm directly in the resin forming the adhesive, it is difficult to uniformly disperse the heat storage capsule in the adhesive. Therefore, it is difficult to obtain a heat storage adhesive sheet with a certain quality.

  In addition, in order to increase the heat storage performance, when adding a large amount of heat storage capsules, uniform mixing and dispersion become more difficult, and as the amount of heat storage capsules added increases, the stickiness, elongation rate, Breaking strength is reduced, sticking to the object to be cooled and casing, surface followability cannot be demonstrated, and strength (breaking strength) required to mechanize sticking work can be maintained. Disappear.

  As introduced in Patent Document 3, a heat storage capsule in which a heat storage agent is sealed in a capsule having a glass transition point of −140 ° C. to −20 ° C. and an outermost layer formed therein is manufactured in advance. It is considered that a heat storage sheet formed by bonding each other through the outermost resin can obtain a heat storage sheet containing a large amount of heat storage capsules and having a uniform dispersion state of the heat storage capsules.

  However, the heat storage sheet manufactured by the above method can be obtained by developing a dried microcapsulated heat storage material powder on a release paper, heating it, adjusting the thickness with a rolling roll, and forming a sheet containing microcapsules. It is formed by applying it on a release paper as it is and then heating it to evaporate the water to form a sheet (Patent Document 3 [0024] column). In the former manufacturing method, a microencapsulated heat storage material is used. The air existing between the powders remains as innumerable bubbles in the heat storage sheet, and in the latter manufacturing method, innumerable bubbles are formed between the capsules by evaporation of moisture.

  As a result, the bubbles formed between the heat storage capsules are considered to be the starting point when the heat storage tape breaks, and the elongation rate and break strength of the heat storage tape are reduced.

  In addition, since the heat storage sheet with the heat storage capsule does not perform new heat storage once the phase transition of the heat storage agent in the heat storage capsule is completed, the heat exceeding the storage capacity is stored inside the electronic device. It will be necessary to release it outside the aircraft.

  However, as described above, the heat storage sheet in which a large number of bubbles are formed, like the foamed resin, exhibits high heat insulation due to the presence of the bubbles, so that heat is easily trapped in the casing of the electronic device. When heat generation exceeding the heat storage amount of the heat storage sheet is performed, the components housed inside may be damaged by heat.

Therefore, the present invention has been made to eliminate the above-mentioned drawbacks of the prior art and includes a large amount of heat storage capsules and exhibits high heat storage performance, but has no voids or bubbles and is subject to cooling. It aims at providing the manufacturing method of the heat storage adhesive sheet which has the self-adhesiveness which can be directly affixed with a thing etc., and was provided with high adhesive force, elongation rate, and breaking strength.

In order to achieve the above object, the method for producing a heat storage pressure-sensitive adhesive sheet of the present invention comprises 20 to 250 parts by weight of a heat storage capsule formed by encapsulating a heat storage agent that stores heat by phase transition in a microcapsule, and an acrylic reactive dilution. After mixing 115 to 125 parts by weight of the agent, 75 to 85 parts by weight of the acrylic base polymer and 0.55 to 0.65 parts by weight of the photopolymerization initiator are stirred and defoamed to obtain a mixed resin material. It is characterized by comprising an acrylic viscoelastic body obtained by photoreaction after the material is formed into a film shape (Claim 1).

  In the heat storage pressure-sensitive adhesive sheet having the above-described configuration, it is preferable that the viscosity of the acrylic reaction diluent is 5 to 300 (mPa · s / 23 ° C.).

  Furthermore, the content of the heat storage capsule in the heat storage pressure-sensitive adhesive sheet is preferably 50 to 60 wt%.

  The film preferably has an adhesive strength of 3.8 (N / 25 mm) or more at 25 ° C. (Claim 4).

  The film preferably has a thickness of 80 μm or more, an elongation of 235 (%) or more, and a breaking strength of 0.5 (N / 10 mm) or more.

With the configuration of the present invention described above, the following remarkable effects could be obtained in the method for producing a heat storage pressure-sensitive adhesive sheet of the present invention.

  A reactive diluent having a lower viscosity than that of an acrylic base polymer, in particular, an acrylic reactive diluent having a viscosity in the range of 5 to 300 (mPa · s / 23 ° C.) and a heat storage capsule are mixed, and then acrylic. It is possible to uniformly disperse the heat storage capsules with fine particle size in the acrylic adhesive by mixing it with the base polymer and the photopolymerization initiator, and the familiarity between the heat storage capsule and the acrylic adhesive. As a result of the favorable prevention of bubbles and the like in the obtained adhesive film, heat storage capsules can be included in a large amount of about 60 wt% at maximum. However, it was possible to obtain a heat storage adhesive sheet having high mechanical properties (adhesive strength, elongation, breaking strength).

  As a result, the heat storage pressure-sensitive adhesive sheet thus obtained is adhered to a cooling object such as an electronic component housed in an electronic device, a heat generating component such as a battery, or a base on which the heat generating component is mounted, or By adhering to the object to be cooled and the inner surface of the casing, the heat generated by the object to be cooled is stored in the heat storage adhesive sheet, thereby suppressing the heat radiation to the outside while suitably cooling the object to be cooled or As a result, it is possible to prevent other machinery and equipment used in contact with electronic equipment from being damaged by heat, and to make the user feel uncomfortable heat. I was able to prevent it.

  In addition, since the heat storage pressure-sensitive adhesive sheet of the present invention uses an acrylic base polymer as a main component, it is not affected by siloxane volatilization as in the case of using a silicon base polymer.

  The adhesive strength tends to decrease under high temperature conditions. However, if it has an adhesive strength of 3.8 (N / 25mm) or higher at 25 ° C, the required adhesive strength is also required under high temperature conditions. You can show your power.

  Furthermore, the heat storage pressure-sensitive adhesive sheet of the present invention has a thickness of 80 μm or more, a breaking strength of 0.5 (N / 10 mm) or more, and has achieved a high elongation rate of 235 (%) or more. Even when combined, it was difficult to peel off.

Explanatory drawing of the measuring method of the thermal storage performance evaluation test 2 (a restriction | limiting of heat transfer, or measurement of delay performance). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement base temperature of 40 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature 50 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature 60 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature 70 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature 80 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature 90 degreeC). The graph which shows the measurement result of the thermal storage performance evaluation test 2 (measurement stand temperature of 100 degreeC). The assumption figure of the attachment state of the heat storage sheet with respect to an electronic device.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

〔overall structure〕
The heat storage pressure-sensitive adhesive sheet manufactured by the manufacturing method of the present invention has a structure in which a heat storage capsule in which a heat storage agent that stores heat by phase transition is dispersed in an acrylic pressure-sensitive adhesive. The heat storage agent enclosed in the capsule is configured to be able to store heat by changing the phase from solid to liquid without changing the state of the capsule.

[Heat storage capsule]
The heat storage capsule used in the heat storage pressure-sensitive adhesive sheet of the present invention is an encapsulated resin capsule (microcapsule) having a particle size of several μm to several tens of μm that forms an outer shell so as not to leak the heat storage agent. Such heat storage capsules are known per se.

  When the melting point of the heat storage agent enclosed in the capsule is lower than the outside air temperature, the heat storage agent is always in the state after the phase transition (liquid state), so it does not store heat even if it receives heat from the object to be cooled. .

  On the other hand, if the melting point of the heat storage agent is too high, heat absorption by the phase transition is not performed until the temperature of the object to be cooled rises near the melting point temperature, and the object to be cooled may be damaged by the heat, and the heat may not be stored. The casing temperature rises due to the heat released to the outside of the machine, and there is a risk of damaging the casing, equipment, equipment, or user in contact with the casing due to heat.

  From the above points, the melting point of the heat storage agent used in the heat storage pressure-sensitive adhesive sheet of the present invention is preferably, for example, in the range of 40 to 60 ° C., and the material and the like are not particularly limited. Paraffin which can set the melting point temperature relatively easily by selection can be suitably used as the heat storage agent.

  Also, the material of the capsule that is the outer shell is not particularly limited as long as the required heat resistance is obtained, and various known materials can be used as the material of the outer shell (capsule) of the heat storage capsule. In this embodiment, a melamine resin capsule is used as an example.

  The above-described heat storage capsule may be dispersed in the adhesive in units of individual particles (primary particles), or secondary particles in which a plurality of heat storage capsules (primary particles) are aggregated or combined. As an example, in the present embodiment, a heat storage capsule having a particle size of several tens of μm by combining many primary particles of about several μm is dispersed (secondary particles). Yes.

[Acrylic adhesive]
The pressure-sensitive adhesive constituting the heat storage pressure-sensitive adhesive sheet of the present invention is a photocurable acrylic pressure-sensitive adhesive, and includes an acrylic base polymer, an acrylic reactive diluent, and a polymerization reaction initiator.

  The acrylic pressure-sensitive adhesive may contain pigments and various adjusting agents as necessary.

Examples of the resin that can be used as the acrylic base polymer include a photocurable resin having an unsaturated carboxylic acid represented by a chemical formula CH ₂ ═CHCOOH, such as 2-ethylhexyl acrylate.

  As the acrylic reactive diluent, a relatively low viscosity acrylic reactive resin can be used, preferably having a viscosity of 5 to 300 mPa · s / 23 ° C., more preferably 200 to 300 mPa · s / 23 ° C. Use one. Examples of such an acrylic reactive diluent include “light acrylate LA” (Kyoeisha Chemical Co., Ltd.), which is a long chain acrylate.

  As the polymerization reaction initiator, α-hydroxyalkylphenone (1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, etc.) can be exemplified.

[Production method of heat storage adhesive sheet]
Table 1 shows the composition of the raw materials used.

  The heat storage pressure-sensitive adhesive sheet is manufactured by first mixing and stirring the heat storage capsule with the acrylic reaction diluent, dispersing the heat storage capsule in the acrylic reaction diluent, and applying the acrylic reaction diluent on the surface of the heat storage capsule. Make sure you are fully familiar.

  Next, the acrylic reaction diluent in which the heat storage capsules are dispersed, the acrylic base polymer, and the polymerization initiator are mixed and stirred, bubbles generated during the stirring are defoamed, and thickening during stirring is prevented. Prepare the mixture at room temperature and normal pressure, and thoroughly degas the mixture.

  The mixed resin material manufactured as described above is processed to a certain thickness while preventing reaction inhibition by physical force through release paper or the like, and then irradiated with light (UV). By starting the polymerization reaction, a heat storage adhesive sheet having a smooth surface with a thickness of 80 μm or more, preferably 80 to 500 μm is obtained.

  The heat storage pressure-sensitive adhesive sheet obtained as described above contains a large amount of heat storage capsules of 50 to 60 wt%, but has an adhesive strength of 3.8 (N / 25 mm) or more at 25 ° C. It had excellent mechanical properties such as a rate of 235 (%) or more and a breaking strength of 0.5 (N / 10 mm) or more.

  The above mechanical characteristics are slightly inferior to the mechanical strength of the adhesive film that does not include the heat storage capsule and is composed of only acrylic adhesive, but the electronic component, the substrate on which it is mounted, and the liquid crystal display It has sufficient adhesive strength to adhere directly to the object to be cooled, such as the back surface of the battery, the surface of the battery, and the inner surface of the casing, and has the strength necessary for use as an adhesive film.

  In addition, the heat storage pressure-sensitive adhesive sheet of the present invention having a relatively high elongation rate is excellent in stress relaxation characteristics and deformability, and has good surface followability with respect to the shape and step of the sticking surface. It can be performed efficiently and there is no risk of heat generation due to friction with the object to be cooled.

  Examples of the present invention will be described below.

[Production Examples]
The heat storage pressure-sensitive adhesive sheets having four different blending patterns shown in Table 3 were produced according to the materials and blending ratios shown in Table 2.

[Confirmation test of mechanical properties]
Three types of heat storage adhesive sheets (3 sheets each) having a thickness (80 μm, 100 μm, and 200 μm) were manufactured according to the combination pattern of “Pattern 2”, and the mechanical characteristics were measured. The results are shown in Table 4.

  The “acrylic pressure-sensitive adhesive” shown for comparison in the table below has the same composition as the acrylic pressure-sensitive adhesive constituting the heat storage pressure-sensitive adhesive sheet except that it does not include a heat storage capsule.

  In the table below, “Adhesive strength” is measured by the 180 ° peel test specified in JIS Z 0237, and “Elongation rate” is determined by pulling the heat storage adhesive sheet (10 mm width) at a speed of 200 mm / min until it breaks. The original length is L1, the length at break is L2, and is calculated as [(L2−L1) / L1] × 100 (%). The load in the tensile direction applied to the sheet was measured under a temperature condition of 25 ° C.

  From the results of the above mechanical properties, in the comparison of films having a thickness of 100 μm, the heat storage pressure-sensitive adhesive sheet of the present invention including the heat storage capsule is somewhat inferior in adhesive strength and elongation rate compared with the acrylic pressure-sensitive adhesive not including the heat storage capsule. It has become. However, the measured adhesive strength and elongation were sufficient for use as an adhesive film.

  The breaking strength was almost the same as that of the acrylic pressure-sensitive adhesive without heat storage capsule, and there was almost no decrease in strength due to mixing of the heat storage capsule.

  As for the relationship between thickness and mechanical properties, it has been confirmed that both properties improve as the thickness increases. If the thickness is 80 μm or more, it is directly attached to the cooling object such as electronic parts. It has been confirmed that the necessary adhesiveness to achieve the desired elongation, the elongation required to obtain surface followability, and the breaking strength capable of preventing breakage during the sticking operation can be obtained.

[Evaluation test for heat storage]
(1) Thermal storage evaluation test 1 (measurement with a differential scanning calorimeter)
Using a differential scanning calorimeter (“EXSTAR6000” manufactured by Hitachi High-Tech Science Co., Ltd.), using a DSC thermogram obtained by measuring at a temperature rising / falling rate of 1 ° C./min, The thermal characteristics of the heat storage adhesive sheet and the heat storage adhesive sheet of Pattern 2 were evaluated.

  From the measurement result by the differential scanning calorimeter, the heat amount (heat absorption amount) at the time of temperature rise of the heat storage adhesive sheet of the present invention is 76.2 mJ / mg in Pattern 1 (heat storage agent melting point 39 ° C., heat storage capsule content 50 wt%), In pattern 3 (heat storage agent melting point 58 ° C., heat storage capsule content 50 wt%), it is 52.3 mJ / mg, all exhibiting high endothermic properties, and the components for which the heat storage adhesive sheet of the present invention is to be cooled It has been confirmed that the use of these parts in contact with both the cooling of these parts, etc., and the effect of suppressing or delaying heat radiation to the outside of the machine can be achieved.

  The thermogram of the heat storage adhesive sheet of pattern 1 (heat storage agent melting point 39 ° C) showed an exothermic peak due to crystallization at 30 ° C and an endothermic peak due to melting at 39 ° C, whereas the heat storage agent used In pattern 3 (heat storage agent melting point 58 ° C), the exothermic peak due to crystallization is 52 ° C and the endothermic peak due to melting is 60 ° C, and both the exothermic peak and endothermic peak are shifted to the high temperature side. Was confirmed.

  From the above results, it can be seen that more appropriate heat countermeasures can be taken by selecting the melting point of the heat storage agent to be used according to the difference in the heat generation temperature of the heat source.

  For example, for applications where the temperature rises and falls drastically and ease of cooling is required, the use of a heat storage adhesive sheet (pattern 1 in this example) using a heat storage agent with a relatively low melting point is suitable, while the temperature of the heat source is always high. When transitioning in the region (50 ° C to 100 ° C), it is appropriate to use a heat storage adhesive sheet (pattern 3 in this example) that uses a heat storage agent with a relatively high melting point. By using different sheets, you can take better heat countermeasures.

(2) Thermal storage performance evaluation test 2 (measurement of heat transfer limitation or delay performance)
Test Method As shown in FIG. 1, the heat storage adhesive sheet of the present invention was sandwiched between two aluminum plates (both 90 mm long, 50 mm wide and 0.2 mm thick), and a heater was built in this state. Press on the measuring table with a pressure of 0.15 MPa, raise the temperature of the measuring table to 40 ° C, 50 ° C, 60 ° C, 70 ° C, 80 ° C, 90 ° C and 100 ° C, respectively, for a predetermined time (1 minute) , 5 minutes, 10 minutes, 20 minutes, 30 minutes, 60 minutes), the change in the surface temperature of the upper aluminum plate was measured with a thermal sensor (thermocouple).

  As the heat storage pressure-sensitive adhesive sheet sandwiched between the aluminum plates, as shown in Table 5 below, eight types of heat storage pressure-sensitive adhesive sheets (Examples 1 to 8) with different addition states and thicknesses were prepared.

  The comparative example is a result of measuring the change in the surface temperature of the upper aluminum plate in a state where the upper and lower aluminum plates are in direct contact with nothing being sandwiched.

Test results The measurement results of the surface temperature of the upper aluminum plate are shown in FIGS.
2-8, in all of Examples 1-8, the rising rate of the surface temperature of the upper aluminum plate is gradual and the maximum temperature reached is lower than that of the comparative example at any temperature increase temperature. Therefore, it was confirmed that the increase in the surface temperature of the upper aluminum plate was suppressed, and heat transfer to the upper aluminum plate could be limited or delayed by heat storage.

  Further, in comparison with the measurement results of Examples 1 to 4 shown in FIG. 8A, the measurement results of Examples 5 to 8 shown in FIG. 8B are all the surface temperature (maximum value) of the upper aluminum plate. ) Can be kept lower, and it was confirmed that higher heat storage performance can be achieved by increasing the amount of heat storage capsule added when the temperature rise is high.

  On the other hand, in comparison with Examples 1, 3, 5, and 7 using a heat storage adhesive sheet having a thickness of 80 μm and Examples 2, 4, 6, and 8 using a heat storage adhesive sheet having a thickness of 500 μm, No change was observed, and it was confirmed from this measurement result that high heat storage performance can be exhibited even with a relatively thin heat storage adhesive sheet of about 80 μm.

Claims (5)

After mixing 200 to 250 parts by weight of a heat storage capsule formed by encapsulating a heat storage agent that stores heat by phase transition in a microcapsule and 115 to 125 parts by weight of an acrylic reactive diluent, 75 to 85 weight of an acrylic base polymer And a photopolymerization initiator (0.55 to 0.65 parts by weight) with stirring and defoaming to obtain a mixed resin material. The mixed resin material was formed into a film and then photoreacted to obtain an acrylic viscosity. A method for producing a heat storage pressure-sensitive adhesive sheet comprising an elastic body. The method for producing a heat storage pressure-sensitive adhesive sheet according to claim 1, wherein the viscosity of the acrylic reaction diluent is 5 to 300 (mPa · s / 23 ° C). 3. The method for producing a heat storage pressure-sensitive adhesive sheet according to claim 1, wherein the content of the heat storage capsule in the heat storage pressure-sensitive adhesive sheet is 50 to 60 wt%. The method for producing a heat storage pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the film has an adhesive strength under a condition of 25 ° C of 3.8 (N / 25 mm) or more. 5. The heat storage according to claim 1, wherein the film has a thickness of 80 μm or more, a breaking strength of 0.5 (N / 10 mm) or more, and an elongation of 235 (%) or more. A method for producing an adhesive sheet.

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