Adhesive laminate

Abstract

To create an adhesive laminate that achieves both conformability to uneven surfaces and heat resistance. [Solution] This adhesive laminate has a base material made of rolled copper foil and an adhesive layer made of a silicone-based adhesive laminated on the base material, and is used for attaching to uneven surfaces.

Description

Technical Field

[0001] The present invention relates to an adhesive laminate.

Background Art

[0002] Patent Document 1 discloses a thermally conductive composite sheet used for heat dissipation of electronic components in an electronic terminal. This thermally conductive composite sheet has a thermally conductive layer having thermal conductivity in the plane direction and a thermally conductive adhesive layer laminated on the thermally conductive layer. Then, this thermally conductive composite sheet is used by being attached to a case of an electronic terminal so as to face an electronic component through, for example, an air gap.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There may be a case where an adhesive laminate having a heat-conductive base material and an adhesive layer laminated on this base material is used by being attached to a concavo-convex object which is a three-dimensional object having concavities and convexities on its surface. In this case, in order to enhance the adhesion between the adhesive laminate and the concavo-convex object, it is preferable that the adhesive laminate follows the surface of the concavo-convex object. Further, when the concavo-convex object to which the adhesive laminate is attached becomes high in temperature, it is preferable that the adhesive laminate has high heat resistance in order to suppress peeling of the adhesive laminate from the concavo-convex object.

[0005] An object of the present invention is to realize an adhesive laminate that achieves both followability with respect to a concavo-convex object and heat resistance.

Means for Solving the Problems

[0006] The adhesive laminate of the present invention comprises a base material made of rolled copper foil and an adhesive layer laminated on the base material, and is used for attaching to uneven surfaces. Here, the base material consists of rolled copper foil that has undergone annealing. Furthermore, the adhesive layer does not contain fillers. From another perspective, the adhesive laminate of the present invention is used for bonding to uneven surfaces where the substrate thickness is in the range of 9 μm to 140 μm, and the difference between the recessed and convex portions is greater than 0 mm and 10 mm or less. Furthermore, the adhesive laminate of the present invention can be used to attach a temperature sensor to an object whose temperature is to be measured. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize an adhesive laminate that achieves both conformability to uneven surfaces and heat resistance. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the configuration of an adhesive laminate to which this embodiment is applied. [Figure 2] This figure shows an example of the use of the adhesive laminate of this embodiment. (a) is a plan view, and (b) is a cross-sectional view taken along the line IIB-IIB in (a). [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the attached drawings. [Structure of the adhesive laminate] Figure 1 shows an example of the configuration of an adhesive laminate 1 to which this embodiment is applied. The adhesive laminate 1 of this embodiment is used, for example, for adhesion to uneven surfaces.

[0010] As shown in Figure 1, the adhesive laminate 1 has a structure in which an adhesive layer 3 is laminated on a base material 2. Although not shown in the figure, the adhesive laminate 1 may optionally include an anchor coat layer between the base material 2 and the adhesive layer 3 to enhance adhesion between the base material 2 and the adhesive layer 3. Furthermore, the surface of the base material 2 (the surface opposite to the surface facing the adhesive layer 3) may be surface-treated. In addition, a release film may be provided on the surface of the adhesive layer 3 (the surface opposite to the surface facing the base material 2).

[0011] <Base material> The base material 2 in this embodiment is made of rolled copper foil. Compared to electrolytic copper foil, rolled copper foil has superior flexibility and ductility, and is also less prone to tearing. Therefore, the adhesive laminate 1 having the base material 2 made of rolled copper foil has high conformability to uneven surfaces and can be attached tightly without tearing. Furthermore, because copper has high thermal conductivity, heat spreads in the planar direction of the adhesive laminate 1, making the temperature of the adhesive laminate 1 uniform.

[0012] The base material 2 is preferably rolled copper foil that has undergone annealing. Annealing increases the flexibility of the rolled copper foil, further improving its ability to conform to uneven surfaces. The annealing conditions are, for example, a temperature of 150°C to 250°C for 3 to 10 hours. The thickness of the base material 2 is preferably in the range of 9 μm to 140 μm, and more preferably in the range of 18 μm to 70 μm. If the thickness of the base material 2 is less than 9 μm, it becomes difficult to maintain a shape that conforms to uneven surfaces. Also, if the thickness of the base material 2 is less than 9 μm, there is a risk that the adhesive laminate 1 will tear during the application process. If the thickness of the base material 2 is greater than 140 μm, the cost will increase. Also, the ability to conform to uneven surfaces will decrease.

[0013] <Adhesive layer> The adhesive layer 3 in this embodiment is made of a silicone-based adhesive. The silicone-based adhesive used in the adhesive layer 3 may be either an addition-type silicone or a peroxide-curing type silicone, or a mixture of an addition-type silicone and a peroxide-curing type silicone. Because the adhesive layer 3 is made of a silicone-based adhesive, the adhesive laminate 1 will not peel off even if the temperature of the uneven surface rises to 200°C.

[0014] Addition-reaction type silicone adhesives are not particularly limited, but examples include KR3700, KR3701, X-40-3237-1, X-40-3240, X-40-3291-1, X-40-3229, X-40-3270, and X-40-3306 from Shin-Etsu Chemical Co., Ltd., TSR1512, TSR1516, and XR37-B9204 from Momentive Performance Materials, Inc., and SD4584, SD4585, SD4560, SD4570, SD4600PFC, and SD4593 from Toray Dow Corning Co., Ltd. Also, in M ​​units (R3SiO 1 / 2 ) and Q units (SiO 4 / 2 A silicone resin that is an organopolysiloxane containing ) can be used. R represents a hydrogen atom, a hydroxyl group, or an organic group, and from the viewpoint of being easily soluble in organic solvents, a methyl group is preferred. The organopolysiloxane may also contain an OH group, a vinyl group, or a phenyl group. SD4580 and SD4584 are examples of such adhesives.

[0015] While there are no particular limitations on the crosslinking agents effective for addition-reaction type silicone adhesives, examples include X-92-122 manufactured by Shin-Etsu Chemical Co., Ltd., CR50 manufactured by Momentive Performance Materials, Inc., and BY24-741 manufactured by Toray Dow Corning Co., Ltd.

[0016] The peroxide-curable silicone adhesive is not particularly limited. For example, there are KR100, KR101-10 manufactured by Shin-Etsu Chemical Co., Ltd., YR3340, YR3286, PSA610-SM, XR37-B6722 manufactured by Momentive Performance Materials Inc., and SH4280 manufactured by Toray Dow Corning Co., Ltd.

[0017] The crosslinking agent effective for the peroxide-curable silicone adhesive is not particularly limited. As the types of organic peroxides, for example, there are benzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1′-di-t-butylperoxy-3,3,5-trimethylenecyclohexane, 1,3-di-(t-butylperoxy)-diisopropylbenzene, and the like.

[0018] The adhesive layer 3 preferably does not contain a filler for enhancing thermal conductivity. By not containing a filler, the adhesive layer 3 can maintain flexibility and adhesive strength without reduction. The thickness of the adhesive layer 3 is preferably in the range of 10 μm or more and 100 μm or less, and more preferably in the range of 20 μm or more and 50 μm or less. When the thickness of the adhesive layer 3 is less than 10 μm, the adhesive force may not be sufficiently high, and the adhesive laminate 1 may be peeled off from the uneven object. When the thickness of the adhesive layer 3 is thicker than 100 μm, the thermal conductivity from the uneven object to the base material 2 decreases.

[0019] The adhesive force of the adhesive laminate 1 measured in accordance with the test of the holding force described in JIS Z 0237(2009) is preferably in the range of 4.5 N / 10 m or more and 5.5 N / 10 mm or less. The adhesive strength of the adhesive laminate 1 can be measured by the following method. First, the adhesive laminate 1 is attached to a stainless steel plate (SUS304) with surface finish BA, and pressed down by rolling a 2000g roller back and forth twice at a speed of 10mm / s. Then, within 1 minute, the adhesive laminate 1 is peeled off the stainless steel plate at a speed of 300mm / min in a 180° direction, and the adhesive strength is measured. The adhesive laminate 1 used should be 19mm or 25mm wide, and the measured adhesive strength result should be converted to a 10mm width (unit: N / 10mm).

[0020] The adhesive laminate 1 preferably has a holding force of 0.1 mm or less, as measured in accordance with the holding force test described in JIS Z 0237 (2009). If the holding force is greater than 0.1 mm, the adhesive laminate is more likely to shift when attached to uneven surfaces caused by the adherend. The holding force of the adhesive laminate 1 can be measured by the following method. First, the adhesive laminate 1 is attached to a stainless steel plate (SUS304) with surface finish BA, and a predetermined weight is attached and it is held in place for 24 hours. Then, the amount of displacement (mm) of the adhesive laminate 1 after holding is measured and defined as the holding force.

[0021] The adhesive laminate 1 of this embodiment, comprising the above-described base material 2 and adhesive layer 3, can be used for bonding to uneven surfaces where the difference between recesses and protrusions is greater than 0 mm and 10 mm or less. It is also more suitable for bonding to uneven surfaces where the difference between recesses and protrusions is between 0.001 mm and 8 mm. Furthermore, it is suitable for bonding to uneven surfaces where the difference between recesses and protrusions is greater than 0.001 mm and 5 mm or less.

[0022] [Method for manufacturing adhesive laminates] Next, the method for manufacturing the adhesive laminate 1 of this embodiment will be described. Note that the method for manufacturing the adhesive laminate 1 described below is just one example, and the method for manufacturing the adhesive laminate 1 is not limited to this example.

[0023] In manufacturing the adhesive laminate 1, first, a silicone-based adhesive and a crosslinking agent are dissolved in a general-purpose organic solvent such as toluene or ethyl acetate to obtain an adhesive solution. Subsequently, this adhesive solution is applied to the surface of the substrate 2, which has undergone surface treatment and anchor coat layer formation as necessary, to a predetermined thickness using a comma coater or the like. Next, the substrate 2 to which the adhesive solution has been applied is heated at a temperature of 60°C to 180°C for several minutes to several tens of minutes to dry and harden the adhesive solution, thereby forming an adhesive layer 3. Through the above process, an adhesive laminate 1 is obtained in which an adhesive layer 3 is laminated on a substrate 2, as shown in Figure 1.

[0024] [How to use adhesive laminates] The adhesive laminate 1 of this embodiment is used for attaching to uneven surfaces. A specific example of its use is for attaching a temperature sensor to an object whose temperature is to be measured. More specifically, it is used to fix a thermocouple to the surface of a power semiconductor chip that drives a lithium-ion battery or an electric motor.

[0025] Figure 2 shows an example of the use of the adhesive laminate 1 of this embodiment. (a) is a plan view, and (b) is a cross-sectional view taken along the line IIB-IIB in (a). As shown in Figure 2(a), a thermocouple 5, as an example of a temperature sensor, is fixed to the surface of the object to be measured 4 by the adhesive laminate 1. In this case, if there is a gap between the object to be measured 4 and the thermocouple 5 and the adhesive laminate 1, the tip of the thermocouple will be in contact with the object to be measured 4 and the low-temperature air in the gap. As a result, it becomes impossible to accurately measure the temperature of the object to be measured 4.

[0026] To accurately measure the temperature of the object to be measured 4, it is necessary to attach the adhesive laminate 1 tightly so that there are no gaps between the object to be measured 4, the thermocouple 5, and the adhesive laminate 1. In this embodiment, the base material 2 of the adhesive laminate 1 is made of rolled copper foil, so it has high conformability to uneven surfaces, and the adhesive laminate 1 can be attached tightly without gaps. Furthermore, even if the adhesive laminate 1 is deformed to prevent gaps between the object to be measured 4 and the thermocouple 5 and the adhesive laminate 1, the adhesive laminate 1 can be attached without tearing. In addition, since copper used as the material for the base material 2 has high thermal conductivity, the adhesive laminate 1 reaches a uniform temperature. Therefore, the tip of the thermocouple 5 comes into contact with the object to be measured 4 and the adhesive laminate 1, which are at a uniform temperature, enabling accurate temperature measurement.

[0027] If the object to be measured (object 4) is a lithium-ion battery or a power semiconductor chip that drives an electric motor in a vehicle, the temperature of the lithium-ion battery or power semiconductor chip is measured while the vehicle is actually driven. When the vehicle is driven and a load is placed on the lithium-ion battery or power semiconductor chip, the lithium-ion battery or power semiconductor chip generates heat and becomes hot. The adhesive laminate 1 of this embodiment includes an adhesive layer 3 made of a silicone-based adhesive. Therefore, even when the temperature of the lithium-ion battery or power semiconductor chip reaches 200°C, the adhesive strength does not decrease, and accurate temperature measurement can be continued.

[0028] Although embodiments have been described above, the technical scope of the present invention is not limited to the embodiments described above. It is clear from the claims that combinations of two or more of the above embodiments, as well as various modifications or improvements to the above embodiments, are also included in the technical scope of the present invention. [Examples]

[0029] Next, the present invention will be described in more detail using examples. However, the present invention is not limited to the following examples.

[0030] (Fabrication of adhesive laminate 1) Toluene, an addition-type silicone adhesive, and a crosslinking agent were mixed and stirred to prepare the adhesive solution. As the addition-type silicone adhesive, an addition-reaction type silicone adhesive consisting of an organopolysiloxane having a vinylsilyl group as a silicon atom-bonded alkenyl group in the molecule was used. Next, this adhesive solution was applied to a substrate 2 made of rolled copper foil with a thickness of 35 μm, and then heated at a temperature of 180°C for 3 minutes to form an adhesive layer 3 with a thickness of 30 μm after drying. This resulted in an adhesive laminate 1 with a total thickness of 65 μm after drying.

[0031] (evaluation) Using the adhesive laminate 1 prepared by the method described above, a test was conducted to attach a thermocouple 5 to an aluminum plate. The diameter of the ball at the tip of the thermocouple 5 was 1 mm. The thermocouple 5 was placed on the aluminum plate, and the adhesive laminate 1 was attached on top of it. Furthermore, the adhesive laminate 1 was deformed to eliminate the gap between the aluminum plate, the ball portion of the thermocouple 5, and the adhesive laminate 1. Since the base material 2 of the adhesive laminate 1 is made of rolled copper foil that has high conformability to uneven surfaces and is resistant to tearing, it was confirmed that the adhesive laminate 1 can be attached without tearing, without creating any gaps between the aluminum plate, the ball portion of the thermocouple 5, and the adhesive laminate 1, and that it does not peel off easily. [Explanation of Symbols]

[0032] 1...Adhesive laminate, 2...Substrate, 3...Adhesive layer, 4...Object to be measured, 5...Thermocouple

Claims

1. A base material made of rolled copper foil, It consists of a silicone-based adhesive, and the adhesive layer laminated on the substrate and An adhesive laminate having the properties of an adhesive laminate used for attaching to uneven surfaces.

2. The adhesive laminate according to claim 1, wherein the substrate is made of rolled copper foil that has been annealed.

3. The adhesive laminate according to claim 1, wherein the adhesive layer does not contain a filler.

4. The thickness of the substrate is in the range of 9 μm or more and 140 μm or less. The adhesive laminate according to claim 1, which is used for attaching to an uneven surface in which the difference between the concave and convex portions is greater than 0 mm and less than or equal to 10 mm.

5. The adhesive laminate according to claim 1, used for attaching a temperature sensor to an object whose temperature is to be measured.

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