JP2017088716A - Thermally peelable pressure-sensitive adhesive sheet, and production method of component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally peelable pressure-sensitive adhesive sheet which is excellent in adhesiveness to an article to be processed and in peelability on heating, and with which positional displacement of the article to be processed can be prevented, and to provide a production method of a component, for which final finish by polishing or the like may not necessarily be conducted by preventing positional displacement of the article to be processed.SOLUTION: A thermally peelable pressure-sensitive adhesive sheet 1 includes: a bimetal substrate 2; and thermal-expansion type microcapsules 4 carried on the bimetal substrate 2 via a conductive pressure-sensitive adhesive layer 3. A production method of a component includes: a step to temporarily fix an article to be processed 100 to the thermally peelable pressure-sensitive adhesive sheet 1 by sticking it thereto; a step to work the article to be processed 100 which is temporarily fixed to the thermally peelable pressure-sensitive adhesive sheet 1; and a step to peel off the thermally peelable pressure-sensitive adhesive sheet 1 from the article to be processed 100 by heating the thermally peelable pressure-sensitive adhesive sheet 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat-peelable pressure-sensitive adhesive sheet used in various parts processing such as wire electric discharge machining, and a method for producing a part using the heat-peelable pressure-sensitive adhesive sheet.

Conventionally, in wire electric discharge machining using a wire electric discharge machine, parts are cut out from a workpiece (workpiece) such as a metal block. At the time of wire electric discharge machining, as the cutout progresses, the support portion of the work piece is reduced, and thus the position deviation of the work piece may occur. Therefore, processing accuracy is ensured by cutting out the workpiece and performing final finishing by polishing or the like.
However, in recent years, with the miniaturization and refinement of parts, it has become difficult to perform final finishing by polishing or the like, and it is strongly desired to prevent misalignment of the workpiece during wire electric discharge machining.
On the other hand, in the manufacture of semiconductor elements, electronic components, etc., when performing various processing such as cutting on the workpiece, temporary fixing that temporarily fixes the workpiece to prevent positional displacement of the workpiece. A heat-peelable pressure-sensitive adhesive sheet is used as the material (for example, Patent Documents 1 and 2). Here, the heat-peelable pressure-sensitive adhesive sheet means a pressure-sensitive adhesive sheet that can be peeled off by heating.

JP 2001-49211 A JP 2010-129700 A

In wire electric discharge machining, the use of a heat-peelable pressure-sensitive adhesive sheet has been studied in order to prevent positional displacement of the workpiece.
However, when a conventional heat-peelable pressure-sensitive adhesive sheet is used in wire electric discharge machining, depending on the type of parts to be manufactured, it cannot withstand the load of the work piece. There exists a problem that a processed material will peel from a heat peeling type adhesive sheet. In addition, the conventional heat-peelable pressure-sensitive adhesive sheet also has a problem that it is difficult to peel off from the component during heating.

The present invention has been made to solve the above-described problems, and is excellent in adhesion to a workpiece and peelability during heating, and can prevent displacement of the workpiece. An object of the present invention is to provide a heat-peelable adhesive sheet.
It is another object of the present invention to provide a method for manufacturing a part that prevents positional displacement of a workpiece and does not require final finishing by polishing or the like.

As a result of intensive studies to solve the above problems, the present inventors have used a bimetal substrate as a substrate to be used in the heat-peelable pressure-sensitive adhesive sheet, and heated the conductive material on the bimetal substrate via a conductive adhesive layer. By arranging the expandable microcapsules, it has been found that in addition to the supporting force of the workpiece, the adhesion to the workpiece and the peelability during heating can be improved, and the present invention has been completed.
That is, the present invention is a heat-peelable pressure-sensitive adhesive sheet comprising a bimetal substrate and a thermally expandable microcapsule supported on the bimetal substrate via a conductive pressure-sensitive adhesive layer.
The present invention also includes a step of pasting and temporarily fixing a workpiece to the heat-peelable pressure-sensitive adhesive sheet, a step of processing the workpiece temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet, and the heat-peelable die And heating the pressure-sensitive adhesive sheet to peel the heat-peelable pressure-sensitive adhesive sheet from the workpiece.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the adhesiveness with a to-be-processed object, and the peelability at the time of a heating, and can provide the heat-peelable adhesive sheet which can prevent the position shift of a to-be-processed object. In addition, according to the present invention, it is possible to provide a method for manufacturing a component that prevents the workpiece from being displaced and does not require final finishing by polishing or the like.

2 is a schematic cross-sectional view of the heat-peelable pressure-sensitive adhesive sheet of Embodiment 1. FIG. It is a state figure when the heat-peelable pressure-sensitive adhesive sheet of Embodiment 1 is stuck and fixed to a workpiece. It is a state figure when the heat-peelable adhesive sheet of Embodiment 1 is heated. It is a state figure when the workpiece temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet of Embodiment 1 is subjected to wire electric discharge machining. FIG. 3 is a state diagram when the workpiece is temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet of Embodiment 1 after a part of the workpiece is subjected to wire electric discharge machining. It is a cross-sectional schematic diagram of the heat-peelable pressure-sensitive adhesive sheet of Embodiment 2. It is a state figure when the heat peeling type adhesive sheet of Embodiment 2 is heated. 6 is a schematic cross-sectional view of a heat-peelable pressure-sensitive adhesive sheet according to Embodiment 3. FIG. It is a cross-sectional schematic diagram of the heat-peelable pressure-sensitive adhesive sheet of Embodiment 4.

The heat-peelable pressure-sensitive adhesive sheet of the present invention comprises a bimetallic substrate and thermally expandable microcapsules supported on the bimetallic substrate via a conductive adhesive layer.
In addition, the method for producing a component of the present invention includes a step of pasting a workpiece on the heat-peelable pressure-sensitive adhesive sheet of the present invention and temporarily fixing the workpiece, and processing a workpiece temporarily fixed on the heat-peelable pressure-sensitive adhesive sheet of the present invention. And a step of heating the heat-peelable pressure-sensitive adhesive sheet of the present invention to peel the heat-peelable pressure-sensitive adhesive sheet of the present invention from a workpiece.
Hereinafter, preferred embodiments of a heat-peelable pressure-sensitive adhesive sheet and a method for producing a component according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view of the heat-peelable pressure-sensitive adhesive sheet of the present embodiment. In FIG. 1, a heat-peelable pressure-sensitive adhesive sheet 1 according to the present embodiment is carried on a bimetallic base material 2, a conductive pressure-sensitive adhesive layer 3 formed on the bimetallic base material 2, and the conductive pressure-sensitive adhesive layer 3. And thermally expandable microcapsules 4.

The bimetallic base material 2 is excellent in the supporting force of the workpiece. Therefore, by using the bimetal substrate 2 as the substrate of the heat-peelable pressure-sensitive adhesive sheet 1, it is possible to withstand the load of the workpiece when the workpiece is processed, and to prevent the displacement of the workpiece. Is possible. Furthermore, the bimetal substrate 2 is easily deformed by heating. Therefore, by using the bimetal base material 2 as the base material of the heat-peelable pressure-sensitive adhesive sheet 1, the heat-peelable pressure-sensitive adhesive sheet 1 can be easily peeled from the work piece by heating after processing the work piece.
Here, “bimetal substrate 2” in the present specification means a laminate of two metal substrates having different coefficients of thermal expansion.

In the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment, a bimetal base material 2 is used in which a metal base material 2a having a low coefficient of thermal expansion and a metal substrate 2b having a high coefficient of thermal expansion are bonded together.
It does not specifically limit as a metal base material used for the bimetallic base material 2, A well-known thing can be used. Examples of metal substrates include copper, titanium, aluminum, and alloys thereof. Specifically, a bimetallic substrate 2 using copper as the metal substrate 2a having a small thermal expansion coefficient and aluminum as the metal substrate 2b having a large thermal expansion coefficient; titanium as the metal substrate 2a having a small thermal expansion coefficient, and a thermal expansion coefficient. As the metal substrate 2b having a large thickness, a bimetal substrate 2 using aluminum or the like can be used.

The bimetal substrate 2 preferably has a rigidity capable of preventing deformation due to a load of the workpiece when the workpiece is processed. When the bimetal substrate 2 having such rigidity is used, it is possible to prevent a decrease in accuracy of the wire electric discharge machining, particularly when performing the wire electric discharge machining. Specifically, it is preferable that the bending rigidity of the bimetallic base material 2 is 0.3 GN · m ² or more under room temperature (25 ° C.) conditions.
When the bimetallic base material 2 is heated, the metal base material 2b having a larger coefficient of thermal expansion is greatly expanded, and therefore, the bimetallic base material 2 is bent toward the metal base material 2a having a small coefficient of thermal expansion. The deformation behavior due to heating of such a bimetal substrate 2 is expressed by the following formulas 1 and 2.

  In the above formula, r = radius of curvature (m), α1 = linear expansion coefficient (1 / ° C.) of the metal base 2a having a small coefficient of thermal expansion, α2 = linear expansion coefficient of the metal substrate 2b having a large coefficient of thermal expansion (1 / C), T1 = initial temperature (° C.), T2 = heating temperature (° C.), h1 = thickness (m) of the metal base 2a having a small coefficient of thermal expansion, h2 = thickness of the metal substrate 2b having a large coefficient of thermal expansion. (M), E1 = longitudinal elastic modulus (Pa) of the metal substrate 2a having a small coefficient of thermal expansion, E2 = longitudinal elastic modulus (Pa) of the metal substrate 2b having a large coefficient of thermal expansion, δ = deflection of the bimetallic substrate 2 (M), L = length (m) of the bimetallic substrate 2.

  The thickness of the bimetal substrate 2 is not particularly limited, and may be set as appropriate according to the type of workpiece to be supported (fixed) by the heat-peelable pressure-sensitive adhesive sheet 1. For example, when the heat-peelable pressure-sensitive adhesive sheet 1 is used in wire electric discharge machining, the thickness of the bimetal substrate 2 is preferably 5 mm or less, more preferably 4 mm or less, and further preferably from the viewpoint of preventing the accuracy of wire electric discharge machining from being reduced. Is 3 mm or less. Further, from the viewpoint of securing the supporting force for the workpiece, the thickness of the bimetal substrate 2 is preferably 0.1 mm or more, more preferably 0.2 mm or more, and further preferably 0.3 mm or more.

The conductive pressure-sensitive adhesive layer 3 formed on the surface of the metal base 2b having a large coefficient of thermal expansion of the bimetal base 2 is a layer necessary for bonding the heat-peelable pressure-sensitive adhesive sheet 1 to a workpiece. This conductive adhesive layer 3 is formed from a conductive adhesive.
The conductive pressure-sensitive adhesive is not particularly limited, and those known in the technical field can be used, but the conductive pressure-sensitive adhesive includes a thermoplastic resin that does not inhibit the volume expansion of the thermally expandable microcapsule 4 during heating. A conductive adhesive in which a filler is dispersed is preferable. Examples of the pressure-sensitive adhesive used for the conductive pressure-sensitive adhesive having such characteristics include a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a styrene-butadiene-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a polyester-based pressure-sensitive adhesive. . Examples of the conductive filler include conductors such as carbon black, metal fine powder, metal oxide, and metal fiber, and glass or resin powder subjected to metal surface treatment such as plating. These pressure-sensitive adhesives and conductive fillers can be used alone or in combination of two or more.

  The thickness of the conductive pressure-sensitive adhesive layer 3 is not particularly limited. However, when the heat-peelable pressure-sensitive adhesive sheet 1 is bonded to the workpiece, sufficient contact between the workpiece and the conductive pressure-sensitive adhesive layer 3 is ensured. From the viewpoint, it is preferable that the particle diameter of the thermally expandable microcapsule 4 is larger. Further, when the conductive adhesive layer 3 is thick, the processing accuracy is liable to decrease due to shear deformation. Therefore, the thickness of the conductive adhesive layer 3 is preferably 200 μm or less, more preferably 100 μm or less, and still more preferably. 50 μm or less.

  The thermally expandable microcapsule 4 expands in volume by heating. Therefore, by using the heat-expandable microcapsule 4 for the heat-peelable pressure-sensitive adhesive sheet 1, the contact area between the work piece and the conductive pressure-sensitive adhesive layer 3 is reduced by heating after the work piece is processed. As a result, the adhesive force between the workpiece and the conductive pressure-sensitive adhesive layer 3 becomes weak, and the heat-peelable pressure-sensitive adhesive sheet 1 can be easily peeled from the workpiece.

The thermally expandable microcapsule 4 is not particularly limited, and a known one can be used. Examples of the thermally expandable microcapsule 4 include a material in which a substance that is easily vaporized and expanded by heating is encapsulated in an elastic shell. Isobutane, propane, pentane, or the like is used as a substance that expands by being vaporized by heating. The shell is formed using a thermoplastic resin such as vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, or polyvinylidene chloride.
Moreover, since the thermally expandable microcapsule 4 is commercially available, such a commercially available product may be used. Examples of commercially available products include “Matsumoto Microsphere” (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), “Kureha Microsphere” (manufactured by Kureha Co., Ltd.), and “Advancel” (manufactured by Sekisui Chemical Co., Ltd.). ) And the like.

Since the thermally expandable microcapsule 4 has a different thermal expansion start temperature depending on the type, an appropriate thermally expandable microcapsule 4 may be selected according to the application of the heat-peelable pressure-sensitive adhesive sheet 1. The thermal expansion start temperature of the thermally expandable microcapsule 4 is not particularly limited, but is preferably 60 ° C. or higher and 100 ° C. or lower.
When the heat-peelable pressure-sensitive adhesive sheet 1 is used for wire electric discharge machining, the thermally expandable microcapsule 4 becomes a resistor, so that the thermally expandable microcapsule 4 is electrically conductive by performing a surface treatment such as metal deposition or electroless plating. Sexuality may be imparted.
The thermally expandable microcapsule 4 has a strength capable of expanding until the volume expansion coefficient becomes three times or more in order to efficiently reduce the contact area between the workpiece and the conductive adhesive layer 3 by heating. preferable.

  The particle diameter (average particle diameter) of the thermally expandable microcapsule 4 is not particularly limited, and may be set as appropriate according to the thickness of the conductive pressure-sensitive adhesive layer 3. In particular, the particle size of the heat-expandable microcapsule 4 is such that when the heat-peelable pressure-sensitive adhesive sheet 1 is adhered to a workpiece, sufficient contact between the workpiece and the conductive pressure-sensitive adhesive layer 3 is ensured. It is preferable that the thickness is smaller than the thickness of the conductive pressure-sensitive adhesive layer 3. When the particle size of the thermally expandable microcapsule 4 is larger than the thickness of the conductive pressure-sensitive adhesive layer 3, sufficient contact between the work piece and the conductive pressure-sensitive adhesive layer 3 is not ensured, and the heat release type for the work piece is provided. Adhesive strength of the pressure-sensitive adhesive sheet 1 may not be obtained sufficiently.

The amount of the thermally expandable microcapsule 4 supported is not particularly limited, but is preferably 0.1 mg / cm ² or more, more preferably 0.2 mg / cm ^{2 in} order to sufficiently obtain the effect of the thermally expandable microcapsule 4. As mentioned above, More preferably, it is 0.3 mg / cm < ² > or more, Most preferably, it is 0.5 mg / cm < ² > or more. Further, if the amount of the heat-expandable microcapsule 4 is excessively large, sufficient contact between the workpiece and the conductive pressure-sensitive adhesive layer 3 cannot be secured, or the heat-peelable pressure-sensitive adhesive sheet 1 is used for wire electric discharge machining. In some cases, the surface resistance may increase. Therefore, the loading amount of the thermally expandable microcapsule 4 is preferably 50 mg / cm ² or less, more preferably 40 mg / cm ² or less, still more preferably 30 mg / cm ² or less, and particularly preferably 20 mg / cm ² or less.

The thickness of the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is not particularly limited, but is preferably 10 mm or less, more preferably 8 mm or less, still more preferably 5 mm or less, and particularly preferably 3 mm or less.
It does not specifically limit as a manufacturing method of the heat-peelable adhesive sheet 1 of this Embodiment, It can carry out according to a well-known method. For example, after the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment forms a conductive pressure-sensitive adhesive layer 3 by applying a conductive pressure-sensitive adhesive to the metal base 2b side where the bimetallic base 2 has a large coefficient of thermal expansion, It can be produced by spraying thermally expandable microcapsules 4 thereon.

The heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is used as a temporary fixing material that prevents positional displacement of a workpiece when performing various types of processing on the workpiece.
Here, FIG. 2 shows a state diagram (cross-sectional schematic diagram) when the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is stuck to a workpiece and fixed.
As shown in FIG. 2, when the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is attached to the workpiece 100, the conductive pressure-sensitive adhesive layer 3 is deformed and the thermally expandable microcapsule 4 becomes the conductive pressure-sensitive adhesive. It is taken into the layer 3 and integrated. Then, the conductive pressure-sensitive adhesive layer 3 including the thermally expandable microcapsule 4 is in close contact with the workpiece 100. Thus, since the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment can directly contact the conductive pressure-sensitive adhesive layer 3 with the workpiece 100 when pasted on the workpiece 100, the workpiece Adhesiveness to 100 and electrical conductivity can be ensured.

FIG. 3 shows a state diagram (sectional schematic diagram) when the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is heated after the workpiece 100 is processed.
As shown in FIG. 3, when the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is heated, the thermally expandable microcapsule 4 expands, and the contact area between the conductive pressure-sensitive adhesive layer 3 and the workpiece 100 is reduced. Let Moreover, since the bimetallic base material 2 curves to the metal base material 2a side with a small thermal expansion coefficient by heating, it peels from the edge part of the heat peeling type adhesive sheet 1. FIG.

  According to the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment having the above-described features, it is possible to withstand the load of the workpiece 100 by the supporting force of the bimetal base 2 and the conductive pressure-sensitive adhesive layer 3. Since the adhesion to the workpiece 100 is ensured by the adhesive force, it is possible to prevent the positional displacement of the workpiece 100 when the workpiece 100 is processed. Further, by heating the heat-peelable pressure-sensitive adhesive sheet 1 after the workpiece 100 is processed, the bimetallic substrate 2 is deformed and the thermally expandable microcapsules 4 are volume-expanded. The workpiece 100 can be easily peeled off.

Since the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment has the characteristics as described above, it can be used when manufacturing parts from the workpiece 100. Among these, the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment has characteristics suitable for manufacturing parts by wire electric discharge machining.
The method for producing a part from the workpiece 100 is not particularly limited except that the heat-peelable pressure-sensitive adhesive sheet 1 of the present embodiment is used as a temporary fixing material, and can be performed according to a known method. Specifically, the part manufacturing method includes a step of attaching the workpiece 100 to the heat-peelable pressure-sensitive adhesive sheet 1 and temporarily fixing it, and a step of processing the workpiece 100 temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet 1. And a step of heating the heat-peelable pressure-sensitive adhesive sheet 1 to peel the heat-peelable pressure-sensitive adhesive sheet 1 from the workpiece 100.

  The workpiece 100 used in the component manufacturing method is not particularly limited, and an appropriate material may be selected according to the processing method. For example, when wire electric discharge machining is used as the machining method, the workpiece 100 is selected from materials having conductivity. Although it does not specifically limit as a material which has electroconductivity, Steel materials, a cemented carbide alloy, a nonferrous alloy, a diamond sintered material, etc. can be used.

When the workpiece 100 is attached to the heat-peelable pressure-sensitive adhesive sheet 1 and temporarily fixed, the heat-peelable pressure-sensitive adhesive sheet 1 is provided on at least one surface of the workpiece 100.
The processing method of the workpiece 100 is not particularly limited, and various known methods can be used. The processing conditions may be set as appropriate according to the type of processing method. For example, when wire electric discharge machining is used as the machining method, the machining voltage is generally set in a range of 50V to 300V. The lower the machining voltage, the smaller the machining roughness and the machining accuracy. However, if the machining voltage is less than 50V, the machining is possible, but the discharge is less likely to occur stably, and the workability may be reduced. On the other hand, when the machining voltage exceeds 300 V, the machining roughness increases, and the machining accuracy may decrease.

Here, FIG. 4 shows a state diagram (sectional schematic diagram) when the workpiece 100 temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet 1 is subjected to wire electric discharge machining.
Wire electric discharge machining is performed using a wire electric discharge machine. The wire electric discharge machine includes a wire line, a wire wire supply unit and a recovery unit, a guide unit for guiding the wire line, a table on which the workpiece 100 is placed, a power source for applying a current, and the like. In FIG. 4, only the supply unit and the recovery unit of the wire electric discharge machine are shown for easy understanding.
As shown in FIG. 4, the workpiece 100 temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet 1 is sent out from the supply unit 50 of the wire electric discharge machine and cut out by the wire line 52 collected by the collection unit 51. A cutout portion 53 is formed.

Further, when wire electric discharge machining is used as a machining method of the workpiece 100, the method further includes a step of wire electric discharge machining of a part of the workpiece 100 before the step of temporarily fixing the workpiece 100, After the step of temporarily fixing 100, the remaining part of the workpiece 100 is preferably subjected to wire electric discharge machining.
Here, FIG. 5 shows a state diagram (upper surface schematic diagram) when the workpiece 100 is temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet 1 after wire electric discharge machining is performed on a part of the workpiece 100.
When the workpiece 100 is wire-discharge processed after the workpiece 100 is temporarily fixed, the portion to which the workpiece 100 is fixed decreases as the cutout portion 53 increases, and the workpiece 100 is at the final stage of the wire electric discharge machining. In some cases, the positional deviation is likely to occur. As shown in FIG. 5, after a part of the workpiece 100 is subjected to wire electric discharge machining, the workpiece 100 is temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet 1, and the remaining portion of the workpiece 100 (wire discharge after temporary fixing). By subjecting the processed portion 54) to wire electric discharge machining, the workpiece 100 can be fixed to the heat-peelable pressure-sensitive adhesive sheet 1 even at the final stage of wire electric discharge machining. Can be prevented.

It does not specifically limit as a heating method of the heat peeling type adhesive sheet 1, A well-known method can be used. For example, you may heat in air using a hot air dryer, an air dryer, etc., and you may heat by immersing the heat-peelable adhesive sheet 1 in warm water. In particular, when the thermal conductivity of the workpiece 100 is small, it is preferable to heat in warm water from the viewpoint of heating efficiency.
The heating temperature of the heat-peelable pressure-sensitive adhesive sheet 1 may be appropriately set according to the thermal expansion start temperature of the thermally expandable microcapsule 4 used in the heat-peelable pressure-sensitive adhesive sheet 1 and is not particularly limited. However, if the heating temperature is too high, the workpiece 100 may be thermally expanded and deformed. Therefore, the heating temperature is preferably 100 ° C. or less, more preferably 95 ° C. or less, and even more preferably 90 ° C. or less. is there. Further, if the heating temperature is too low, the heat-peelable pressure-sensitive adhesive sheet 1 may not be easily peeled off. Therefore, the heating temperature is preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and further preferably 70 ° C. or higher.

Embodiment 2. FIG.
FIG. 6 is a schematic cross-sectional view of the heat-peelable pressure-sensitive adhesive sheet of the present embodiment. In FIG. 6, the heat-peelable pressure-sensitive adhesive sheet 10 of the present embodiment is an embodiment in that a conductive pressure-sensitive adhesive layer 3 is formed on the surface of a metal substrate 2a having a low coefficient of thermal expansion of the bimetal substrate 2. 1 and different from the heat-peelable pressure-sensitive adhesive sheet 1. When the heat-peelable pressure-sensitive adhesive sheet 10 is heated, the bimetal substrate 2 is curved toward the conductive pressure-sensitive adhesive layer 3 side. In the heat-peelable pressure-sensitive adhesive sheet 10 of the present embodiment, the deformation direction of the bimetal substrate 2 is opposite to that of the heat-peelable pressure-sensitive adhesive sheet 1 of the first embodiment. 10 peelability is improved. Since the features other than this point are the same as those of the heat-peelable pressure-sensitive adhesive sheet 1 according to Embodiment 1, the description thereof is omitted.

Here, FIG. 7 shows a state diagram (sectional schematic diagram) when the heat-peelable pressure-sensitive adhesive sheet 10 of the present embodiment is heated after the workpiece 100 is processed.
As shown in FIG. 7, when the heat-peelable pressure-sensitive adhesive sheet 10 of the present embodiment is heated, the thermally expandable microcapsule 4 expands, and the contact area between the conductive pressure-sensitive adhesive layer 3 and the workpiece 100 is reduced. Let Moreover, since the bimetallic base material 2 curves to the metal base material 2a side with a small coefficient of thermal expansion by heating, it peels from the center part of the heat peeling type adhesive sheet 10. FIG.

  According to the heat-peelable pressure-sensitive adhesive sheet 10 of the present embodiment having the above-described characteristics, it is possible to withstand the load of the workpiece 100 by the supporting force of the bimetal base 2 and the conductive pressure-sensitive adhesive layer 3. Since the adhesion to the workpiece 100 is ensured by the adhesive force, it is possible to prevent the positional displacement of the workpiece 100 when the workpiece 100 is processed. In addition, by heating the heat-peelable pressure-sensitive adhesive sheet 10 after the workpiece 100 is processed, the bimetallic substrate 2 is deformed and the thermally expandable microcapsules 4 are volume-expanded. The workpiece 100 can be easily peeled off.

Embodiment 3 FIG.
FIG. 8 is a schematic cross-sectional view of the heat-peelable pressure-sensitive adhesive sheet of the present embodiment. In FIG. 8, the heat-peelable pressure-sensitive adhesive sheet 20 of the present embodiment includes a pressure-sensitive adhesive layer 5, a conductive base material 6, and a conductive pressure-sensitive adhesive layer 3 on a metal base material 2 b having a large thermal expansion coefficient of the bimetallic base material 2. Are different from the heat-peelable pressure-sensitive adhesive sheet 1 of Embodiment 1 in that they are sequentially provided. In addition, since it is the same as that of the heat-peelable adhesive sheet 1 of Embodiment 1 about structures other than this point, description is abbreviate | omitted.
The pressure-sensitive adhesive layer 5 is a layer used for bonding the conductive substrate 6 to the bimetal substrate 2. Therefore, the pressure-sensitive adhesive layer 5 may or may not have conductivity, but from the viewpoint of improving the conductivity of the heat-peelable pressure-sensitive adhesive sheet 20, the pressure-sensitive adhesive layer 5 has conductivity. It is preferable. In this case, the conductive pressure-sensitive adhesive layer 3 can be used as the pressure-sensitive adhesive layer 5.

It does not specifically limit as the electroconductive base material 6, A well-known thing can be used. Examples of the conductive substrate 6 include a cloth or a resin subjected to surface treatment such as metal foil and metal plating. Among these, from the viewpoints of availability and versatility, the conductive substrate 6 is preferably a copper foil, an aluminum foil, or a copper-plated polyester film.
The surface of the conductive substrate 6 may be subjected to a surface treatment such as polishing from the viewpoint of improving the adhesion between the two conductive pressure-sensitive adhesive layers 3.
Although the thickness of the electroconductive base material 6 is not specifically limited, From viewpoints of workability | operativity etc., it is preferable that they are 5 micrometers or more and 50 micrometers or less.

The method for sequentially forming the pressure-sensitive adhesive layer 5, the conductive base material 6, and the conductive pressure-sensitive adhesive layer 3 on the bimetal substrate 2 is not particularly limited, and can be performed according to a known method.
For example, after an adhesive is applied on the bimetal substrate 2 to form the adhesive layer 5, the conductive substrate 6 is disposed thereon, and the conductive adhesive is applied on the conductive substrate 6. What is necessary is just to form the electroconductive adhesive layer 3. FIG.

Alternatively, it can be formed by using various commercially available tapes alone or in combination. By using various commercially available tapes, the application of each pressure-sensitive adhesive becomes unnecessary, and thus the heat-peelable pressure-sensitive adhesive sheet 20 can be easily manufactured.
For example, when forming the structure which provided the conductive adhesive layer 3, the conductive base material 6, and the conductive adhesive layer 3 in order on the bimetal base material 2, the two conductive adhesive layers 3 and two electroconductive What is necessary is just to affix the electroconductive double-sided tape which has the electroconductive base material 6 pinched | interposed between the conductive adhesive layers 3 on the bimetal base material 2. FIG. Examples of such a conductive double-sided tape include trade names “AL-25DC” and “X-7001” (manufactured by 3M).
Moreover, when forming the structure which provided the adhesive layer 5, the electroconductive base material 6, and the electroconductive adhesive layer 3 in order on the bimetal base material 2, the double-sided tape which gives the adhesive layer 5 on the bimetal base material 2 After pasting, a conductive single-sided tape in which the conductive adhesive layer 3 is formed on the conductive substrate 6 may be stuck on the double-sided tape. As a double-sided tape which gives the adhesive layer 5, a brand name "VR-5300H" (made by Nitto Denko Corporation) etc. are mentioned. Moreover, as a conductive single-sided tape in which the conductive pressure-sensitive adhesive layer 3 is formed on the conductive substrate 6, a trade name “CU-35C” (manufactured by 3M Co., Ltd.) and the like can be mentioned.

  According to the heat-peelable pressure-sensitive adhesive sheet 20 of the present embodiment having the above-described features, it is possible to withstand the load of the workpiece 100 due to the supporting force of the bimetal substrate 2 and the conductive pressure-sensitive adhesive layer 3. Since the adhesion to the workpiece 100 is ensured by the adhesive force, it is possible to prevent the positional displacement of the workpiece 100 when the workpiece 100 is processed. In addition, by heating the heat-peelable pressure-sensitive adhesive sheet 20 after the workpiece 100 is processed, the bimetallic substrate 2 is deformed and the thermally expandable microcapsules 4 are volume-expanded. The workpiece 100 can be easily peeled off.

Embodiment 4 FIG.
FIG. 9 is a schematic cross-sectional view of the heat-peelable pressure-sensitive adhesive sheet of the present embodiment. In FIG. 9, the heat-peelable pressure-sensitive adhesive sheet 30 of the present embodiment includes a pressure-sensitive adhesive layer 5, a conductive base material 6, and a conductive pressure-sensitive adhesive layer 3 on a metal base material 2 a having a low coefficient of thermal expansion. Are different from the heat-peelable pressure-sensitive adhesive sheet 20 of the third embodiment in that they are sequentially provided. When the heat-peelable pressure-sensitive adhesive sheet 30 is heated, the bimetal substrate 2 is curved toward the pressure-sensitive adhesive layer 5 side. The heat-peelable pressure-sensitive adhesive sheet 30 according to the present embodiment is opposite to the heat-peelable pressure-sensitive adhesive sheet 20 according to the third embodiment in the deformation direction of the bimetal substrate 2, but the heat-peelable pressure-sensitive adhesive sheet also by this deformation. 30 peelability is improved. Since the features other than this point are the same as those of the heat-peelable pressure-sensitive adhesive sheet 20 of Embodiment 3, the description thereof is omitted.

  According to the heat-peelable pressure-sensitive adhesive sheet 30 of the present embodiment having the above-described characteristics, it is possible to withstand the load of the workpiece 100 by the supporting force of the bimetal base 2 and the conductive pressure-sensitive adhesive layer 3. Since the adhesion to the workpiece 100 is ensured by the adhesive force, it is possible to prevent the positional displacement of the workpiece 100 when the workpiece 100 is processed. In addition, by heating the heat-peelable pressure-sensitive adhesive sheet 30 after the workpiece 100 is processed, the bimetallic substrate 2 is deformed and the thermally expandable microcapsules 4 are volume-expanded. The workpiece 100 can be easily peeled off.

Hereinafter, although an Example and a comparative example demonstrate the detail of this invention, this invention is not limited by these.
Example 1
A bimetallic substrate (bending rigidity of 35) in which a copper plate (Young's modulus 129.8 GPa) having a thickness of 0.25 mm and a length of 30 mm and an aluminum plate (Young's modulus of 70.3 GPa) having a thickness of 0.25 mm and a length of 30 mm are bonded together. .6GN · m ² ) as a substrate, and a conductive double-sided tape (trade name “AL-25DC”, manufactured by 3M Corporation) was attached to the surface of the bimetal base on the aluminum plate side. Here, the conductive double-sided tape has a thickness of 85 μm, and an acrylic conductive pressure-sensitive adhesive layer (thickness 30 μm) is formed on both sides of an aluminum foil (thickness 25 μm). Next, a heat-expandable microcapsule (trade name “F-30”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) is sprayed onto the conductive double-sided tape so as to have a supported amount of 1 mg / cm ^2. An adhesive sheet was obtained. Here, the thermally expandable microcapsule has an average particle diameter of 10 to 18 μm and a thermal expansion start temperature of 70 to 80 ° C.

(Example 2)
A double-sided tape (trade name “VR-5300H”, manufactured by Nitto Denko Corporation) was attached to the aluminum plate side surface of the same bimetal substrate as that used in Example 1. Here, the double-sided tape has a thickness of 100 μm, and a special rubber-based pressure-sensitive adhesive layer (thickness 44 μm) is formed on both sides of a polyester film (thickness 12 μm). Next, a conductive single-sided tape (trade name “CU-35C”, manufactured by 3M Company) was attached onto the double-sided tape. Here, the conductive single-sided tape has a thickness of 70 μm, and an acrylic conductive adhesive layer (thickness of 35 μm) is formed on one side of a copper foil (thickness of 35 μm). Moreover, the electroconductive single-sided tape affixed the copper foil side to the double-sided tape. Next, a heat-peelable pressure-sensitive adhesive sheet is sprayed on the conductive double-sided tape by spraying the same thermally expandable microcapsule as the thermally expandable microcapsule used in Example 1 so as to have a supported amount of 1 mg / cm ^2. Got.

(Example 3)
A heat-peelable pressure-sensitive adhesive sheet was obtained using the same materials and methods as in Example 1 except that a conductive double-sided tape was affixed to the copper plate side surface of the bimetal substrate.
Example 4
A heat-peelable pressure-sensitive adhesive sheet was obtained using the same material and method as in Example 2 except that a double-sided tape was affixed to the copper plate side surface of the bimetal substrate.
(Example 5)
A heat-peelable pressure-sensitive adhesive sheet was obtained using the same materials and methods as in Example 2 except that the amount of thermally expandable microcapsules supported was changed to 50 mg / cm ² .

(Example 6)
As a bimetal substrate, a bimetal substrate in which a 0.1 mm thick and 30 mm long copper plate (Young's modulus 129.8 GPa) and an aluminum plate 0.1 mm thick and 30 mm long (Young's modulus 70.3 GPa) are bonded together A heat-peelable pressure-sensitive adhesive sheet was obtained using the same material and method as in Example 1 except that the material (flexural rigidity 2.3 GN · m ² ) was used.
(Example 7)
Other than using thermally expandable microcapsules (trade name “F-48”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) instead of thermally expandable microcapsules (trade name “F-30”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) Used the same material and method as Example 1 to obtain a heat-peelable pressure-sensitive adhesive sheet. Here, the thermally expandable microcapsule used has an average particle diameter of 9 to 15 μm and a thermal expansion start temperature of 90 to 100 ° C.

(Example 8)
Other than using thermally expandable microcapsules (trade name “FN-180SS”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) instead of thermally expandable microcapsules (trade name “F-30”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) Used the same material and method as Example 1 to obtain a heat-peelable pressure-sensitive adhesive sheet. Here, the thermal expansion microcapsule used has an average particle diameter of 15 to 25 μm and a thermal expansion start temperature of 135 to 150 ° C.

(Comparative Example 1)
A heat-peelable pressure-sensitive adhesive sheet was obtained using the same material and method as in Example 2 except that a 0.5 mm-thick copper substrate was used instead of the bimetal substrate.
(Comparative Example 2)
A heat-peelable pressure-sensitive adhesive sheet was obtained using the same materials and methods as in Example 2 except that the thermally expandable microcapsules were not sprayed.
(Comparative Example 3)
A heat-peelable pressure-sensitive adhesive sheet could not be obtained when the same materials and methods as in Example 2 were used except that the amount of thermally expandable microcapsules supported was 100 mg / cm ² . That is, the sheet obtained in this comparative example was a sheet having no adhesiveness. Therefore, the following evaluation was not performed.

As shown in FIG. 4, the heat-peelable pressure-sensitive adhesive sheets obtained in the above examples and comparative examples are pasted on the upper and lower surfaces of a workpiece (dies steel: SKD11, 20 mm × 40 mm × 150 mm), and commercially available wire discharge Wire electric discharge machining was performed using a processing machine (trade name “PA05S”, manufactured by Mitsubishi Electric Corporation). The processing conditions at this time were a processing voltage of 60 V and a processing speed of 1 mm / min. In this evaluation, the heat-peelable pressure-sensitive adhesive sheet was not peeled off from the workpiece during processing (that is, the adhesive was good), and the heat-peelable pressure-sensitive adhesive sheet was removed from the workpiece during processing. What peeled (namely, the thing whose adhesiveness was inadequate) is represented as x.
Next, the processed workpiece was immersed in warm water heated to 80 ° C. for 3 minutes, and the heat-peelable pressure-sensitive adhesive sheet was peeled off from the workpiece. Moreover, about what was not peeled with warm water, it was immersed in the silicone oil heated at 150 degreeC for 3 minutes, and the heat peelable adhesive sheet was peeled from the to-be-processed object. In this evaluation, the heat-peelable pressure-sensitive adhesive sheet that can be easily peeled off from the work piece by immersing in warm water is ○, and the heat-peelable pressure-sensitive adhesive sheet from the work piece by immersing in silicone oil Is represented by Δ, and the heat-peelable pressure-sensitive adhesive sheet cannot be easily separated from the workpiece by ×.
The results of the above evaluations are shown in Table 1.

As shown in the results of Table 1, the heat-peelable pressure-sensitive adhesive sheets of Examples 1 to 8 were not peeled from the work piece during the wire electric discharge machining, and the work piece after processing Thus, the heat-peelable pressure-sensitive adhesive sheet could be easily peeled off.
On the other hand, since the heat-peelable pressure-sensitive adhesive sheet of Comparative Example 1 does not use a bimetal base material, the base material is not deformed when the heat-peelable pressure-sensitive adhesive sheet is peeled from the processed workpiece, and thermal expansion occurs. The heat-peelable pressure-sensitive adhesive sheet could not be easily peeled only by the volume expansion of the conductive microcapsules.
Moreover, since the heat-expandable microcapsule does not use the heat-expandable microcapsule, the heat-expandable microcapsule cannot obtain the effect due to the volume expansion of the heat-expandable microcapsule. The sheet could not be easily peeled off.

  As can be seen from the above results, according to the present invention, the heat-peelable pressure-sensitive adhesive sheet is excellent in adhesion to a workpiece and peelability during heating, and can prevent positional displacement of the workpiece. Can be provided. In addition, according to the present invention, it is possible to provide a method for manufacturing a component that prevents the workpiece from being displaced and does not require final finishing by polishing or the like.

  1, 10, 20, 30 Heat-peelable pressure-sensitive adhesive sheet, 2 Bimetal base material, 2a Metal base material with low thermal expansion coefficient, 2b Metal substrate with high thermal expansion coefficient, 3 Conductive adhesive layer, 4 Thermal expansion microcapsule DESCRIPTION OF SYMBOLS 5 Adhesive layer, 6 Conductive base material, 50 Supply part, 51 Collection | recovery part, 52 Wire wire, 53 Cut-out part, 54 The part processed by wire electric discharge after temporary fixing, 100 Workpiece.

Claims (13)

  A heat-peelable pressure-sensitive adhesive sheet comprising: a bimetal base material; and a thermally expandable microcapsule supported on the bimetal base material via a conductive pressure-sensitive adhesive layer. ^2. The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the amount of the thermally expandable microcapsule supported is 0.1 mg / cm ² or more and 50 mg / cm ² or less.   A conductive substrate is disposed between the bimetal substrate and the conductive adhesive layer, and an adhesive layer is disposed between the bimetal substrate and the conductive substrate. The heat-peelable pressure-sensitive adhesive sheet according to claim 1 or 2, characterized in that   The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein a thickness of the conductive pressure-sensitive adhesive layer is larger than a particle size of the thermally expandable microcapsule.   The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the conductive pressure-sensitive adhesive layer has a thickness of 50 µm or less.   6. The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein a thermal expansion start temperature of the thermally expandable microcapsule is 60 ° C. or higher and 100 ° C. or lower. The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the bimetallic substrate has a bending rigidity of 0.3 GN · m ² or more.   The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the bimetal substrate has a thickness of 5 mm or less.   The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 8, which is used as a temporary fixing material for a workpiece.   The heat-peelable pressure-sensitive adhesive sheet according to claim 9, which is used in wire electric discharge machining. A step of pasting and temporarily fixing a workpiece to the heat-peelable pressure-sensitive adhesive sheet according to claim 9;
Processing the workpiece temporarily fixed to the heat-peelable pressure-sensitive adhesive sheet;
And heating the heat-peelable pressure-sensitive adhesive sheet to peel the heat-peelable pressure-sensitive adhesive sheet from the workpiece.   The method of manufacturing a component according to claim 11, wherein the machining is wire electric discharge machining.   Prior to the step of temporarily fixing the workpiece, the method further includes a step of wire electric discharge machining of a part of the workpiece, and after the step of temporarily fixing the workpiece, the remaining part of the workpiece is wired. The method of manufacturing a component according to claim 12, wherein electric discharge machining is performed.

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