JP2012131904A - Adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape which comprises a substrate and an adhesive in which a temperature of the adhesive does not follow a temperature change of an object to which the adhesive tape is adhered or the environment.SOLUTION: The adhesive tape includes a substrate and an adhesive layer applied on the substrate in which a latent heat storage material is added to the adhesive of a not-adhering surface part in a thickness direction of the adhesive tape, thereby an initial adhesive force is secured, and even if a temperature of an object to which the adhesive tape is adhered changes, the decrease in an adhesion force or the like is not caused.

Description

The present invention relates to a pressure-sensitive adhesive tape, and more particularly to a pressure-sensitive adhesive tape whose pressure-sensitive adhesive performance does not change even when the temperature of an object to which the pressure-sensitive adhesive tape is bonded changes.

The pressure-sensitive adhesive tape is used for applying a pressure-sensitive adhesive to a base material such as paper, cloth, film, metal foil, etc., and adhering, fixing, filling a gap, and protecting a surface of an object.
By the way, when the temperature of the object to which the adhesive tape is bonded is changed, the properties of the adhesive may be changed, and the adhesive force may be reduced. Moreover, although there exists an idea which disperse | distributes the heat storage particle | grains to an adhesive which is disclosed by Unexamined-Japanese-Patent No. 2001-303006, the heat storage particle | grains are non-adhesive materials and initial adhesive force falls by mixing.

JP2001-303006

An object of the present invention is to provide a pressure-sensitive adhesive tape that does not cause deterioration in adhesive strength and the like, even if the temperature of an object on which the pressure-sensitive adhesive tape is bonded changes for a certain period of time. .

The pressure-sensitive adhesive tape of the present invention comprises a base material and a pressure-sensitive adhesive layer coated on the base material. The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer has a latent heat storage material on the non-adhesive surface portion in the thickness direction of the pressure-sensitive adhesive tape. Is added.
The latent heat storage material has a constant temperature at the melting point and freezing point (phase change temperature) of the material until melting or solidification is completed (heat absorption and heat generation energy at this time are referred to as latent heat). Therefore, when the temperature of the system including the latent heat storage material changes across the phase change temperature, it is fixed at the phase change temperature for a certain time. By setting this phase change temperature within a temperature range where the properties of the adhesive do not change, even if the temperature of the object to which the adhesive tape is bonded changes for a certain period of time, the properties of the adhesive will not change. Tape can be provided.
Moreover, since the latent heat storage material does not exist on the surface where the adhesive layer of the adhesive tape adheres to the object, the initial adhesive force is not hindered by the non-adhesive latent heat storage material.
Latent heat storage materials are broadly classified into organic heat storage materials such as normal paraffin and stearic acid, and inorganic heat storage materials such as sodium acetate and calcium chloride hexahydrate. The desired fixed temperature due to the changing temperature is obtained. In addition, by forming the latent heat storage material into microcapsules, it is possible to have a configuration that does not affect the adhesive even when melted.
The amount of latent heat storage material added to the adhesive increases the heat capacity at the phase change temperature and the amount added, so that the fixing temperature can be obtained stably for a long time, and the effect of maintaining the adhesive strength will be maintained. There is an upper limit to cause adhesive structural destruction in the layer.
The addition amount of the latent heat storage material needs to be determined in consideration of the application of the adhesive tape.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
Embodiment of the Invention The latent heat storage material has an effect of maintaining a constant temperature in an environment where the temperature changes. For example, when water is considered, the freezing point of water, the melting point of ice (solid-liquid phase change temperature) is 0 ° C., and all the contained water is solidified in response to a temperature change from 0 ° C. to 0 ° C. The temperature is fixed at 0 ° C. until it becomes ice. In other words, if a latent heat storage material having a unique phase change temperature is included in the system, the system temperature is kept constant during the period in which all of the latent heat storage material is solidified or melted against the temperature change across the phase change temperature. Dripping (heat storage). The total amount of heat energy that enters and exits during solidification and melting is called latent heat. The larger the latent heat, the higher the ability to keep the system temperature constant.
The latent heat storage material may be selected according to the properties of the added adhesive and the application of the adhesive tape. For example, n-tetradecane (phase change temperature 5 ° C.), n-pentadecane (phase change temperature 9 ° C.), n-hexadecane. (Phase change temperature 18 ° C), n-heptadecane (phase change temperature 22 ° C), n-octadecane (phase change temperature 28 ° C), n-nonadecane (phase change temperature 32 ° C), n-icosane (phase change temperature 36 ° C) ), Cetyl alcohol (phase change temperature 51 ° C.), stearic acid (phase change temperature 71 ° C.), water (phase change temperature 0 ° C.), sodium acetate trihydrate (phase change temperature 58 ° C.), calcium chloride hexahydrate ( Phase change temperature 27 ° C), sodium carbonate (phase change temperature -3 ° C), potassium bicarbonate aqueous solution (phase change temperature -6 ° C), potassium chloride aqueous solution (phase change temperature -11 ° C), ammonium chloride aqueous solution (phase change temperature) -16 ℃), sodium chloride Potassium solution (phase change temperature -21 ° C.), and the like.
The latent heat storage material may bleed out from the adhesive layer depending on the viscosity in the dissolved state, compatibility with the adhesive, and the like. In that case, it is preferable to encapsulate the latent heat storage material.
The greater the amount of latent heat storage material added, the greater the latent heat of the adhesive tape and the greater the ability to keep it constant at the phase change temperature, but the latent heat storage material or the microencapsulated latent heat storage material is non-adhesive, In the uniform dispersion to the adhesive layer, the initial adhesive force of the adhesive tape decreases with the addition amount. If this added latent heat storage material does not exist on the adhesive surface side in the thickness direction of the adhesive tape or if it is in a very small amount, the latent heat storage material will not hinder the adhesive and the reduction in the initial adhesive force will be improved. . Therefore, as shown in FIG. 1, a pressure-sensitive adhesive in which a latent heat storage material or a microcapsulated latent heat storage material is dispersed is applied on a base material, and after drying, an adhesive that does not contain a latent heat storage material is further applied. A pressure-sensitive adhesive tape having a layer structure was obtained. Moreover, as shown in FIG. 2, the adhesive which does not contain a latent heat storage material, the adhesive which disperse | distributed the latent heat storage material or the microcapsulated latent heat storage material, and the adhesive which does not contain a latent heat storage material are apply | coated on a separator base material. A three-layer substrate-less double-sided adhesive tape was obtained.
Hereinafter, the Example of the adhesive tape which concerns on this invention is described in detail. A comparative example serving as a comparative control of the examples will also be described.
Example 1
On the PET film, apply a paint in which a microencapsulated latent heat storage material is dispersed in an acrylic adhesive, dry it to form a 100 μm adhesive layer, and then apply an acrylic adhesive paint that does not contain a latent heat storage material Then, it was dried to obtain a two-layered adhesive tape in which a 20 μm adhesive layer was stacked. A part of this adhesive tape was bonded to a smooth surface of SUS, and the temperature until the adhesive tape was peeled was evaluated by changing and holding the SUS temperature at a constant speed while applying a weight of 1 kg to the adhesive tape. For comparison, an acrylic adhesive 150 μm single-layer adhesive tape not containing a latent heat storage material was also evaluated under the same conditions.

Table 1 summarizes the latent heat storage material, temperature change conditions, and peeling time. From this result, by adding the latent heat storage material to the adhesive of the non-adhesive surface layer in the thickness direction of the pressure-sensitive adhesive tape, it becomes a pressure-sensitive adhesive tape in which a decrease in adhesive force is suppressed with respect to the temperature change of the object to be bonded. Was confirmed.

Example 2
An acrylic pressure-sensitive adhesive paint not containing a latent heat storage material is applied onto a PET film coated with a release agent, dried to form a 20 μm pressure-sensitive adhesive layer, and then the microencapsulated latent heat storage material is an acrylic pressure-sensitive adhesive. Apply the coating material dispersed in and dry it to laminate a 200μm adhesive layer, and then apply an acrylic adhesive coating material that does not contain any latent heat storage material, and dry it to laminate a 20μm adhesive layer. A double-sided adhesive tape was used. The smooth surface of a 1 kg weight SUS plate was bonded with this double-sided pressure-sensitive adhesive tape, and the SUS temperature was changed and held at a constant speed while supporting the SUS plate on one side, and the time until the pressure-sensitive adhesive tape was peeled was evaluated. For comparison, an acrylic adhesive 250 μm single-layer adhesive tape not containing a latent heat storage material was also evaluated under the same conditions.
The latent heat storage material, temperature change conditions, and peeling time are summarized in Table 2. From this result, by adding the latent heat storage material to the adhesive of the non-adhesive surface layer in the thickness direction of the adhesive tape, the baseless double-sided adhesive that suppresses the decrease in the adhesive force against the temperature change of the object to be bonded It was confirmed that it became a tape.

Comparative Example The same microencapsulated latent heat storage material as in Example 1 coated with an acrylic adhesive was applied onto a PET film and dried to obtain a 150 μm single-layer adhesive tape. When a pressure of 1 kg was applied to this pressure-sensitive adhesive tape under the same conditions as in Example 1, it was confirmed that a shift occurred at room temperature and the adhesive strength was poor.

Cross-sectional schematic diagram of double-layer adhesive tape Cross-sectional schematic diagram of double-sided adhesive tape with three-layer structure base material

1 ... two-layer adhesive tape, 11 ... PET film, 121,221 ... acrylic adhesive,
12, 22 ... Latent heat storage material encapsulated in microcapsules, 2 ... Double-layer adhesive tape without base material of 3 layers,
21 ... Release agent-coated PET film

Claims (7)

A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive, wherein the temperature of the pressure-sensitive adhesive does not follow the temperature change of an object or environment to which the pressure-sensitive adhesive tape is bonded. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive can be peeled off from the substrate. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive comprises a layer containing a latent heat storage material and a layer not containing a latent heat storage material in the thickness direction. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the content of the latent heat storage material changes in the thickness direction. 5. The pressure-sensitive adhesive tape according to claim 3, wherein the pressure-sensitive adhesive layer on the adhesive surface side with the object does not contain a latent heat storage material. 5. An adhesive tape, wherein the latent heat storage material according to claim 3 or 4 is enclosed in a microcapsule and dispersed in an adhesive. 6. The pressure-sensitive adhesive tape according to claim 5, wherein the phase change temperature of the latent heat storage material undergoes a solid-liquid phase change at −40 ° C. or more and 100 ° C. or less.

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