JP2009160942A - Adhesive structure and adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive structure having an adhesive layer having both of high heat resistant adhesiveness and insulating property, and comprising an adhesive material composed essentially of a composition containing extremely small quantity of or completely no residual low molecular weight siloxane, and also to provide an adhesive film comprising the adhesive material. <P>SOLUTION: A pair of materials to be bonded are bonded with the adhesive layer comprising the adhesive material composed essentially of a composition obtained by hydrolysis reaction and condensation reaction of a mixture having a silicate compound and a poly dimethyl siloxane having a silicate-modified terminal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adhesive structure in which a pair of adherends are bonded by an adhesive layer made of an adhesive, and an adhesive film using the adhesive as a material.

  Conventionally, an epoxy resin, a silicone resin, and a polyimide resin are mainly used as an adhesive (adhesive) used for bonding an adherend used in a high temperature environment of 150 ° C. or higher (for example, Patent Document 1). ~ 5).

JP-A-6-237559 JP-A-5-263062 JP 2002-277185 A JP 2004-107652 A JP 2005-320461 A

  However, several problems occur in the epoxy resin, silicone resin and polyimide resin used as the adhesive.

  Since the epoxy resin and polyimide resin are hard, it is difficult to relieve stress against deformation of the adherend in a high temperature range, and the adhesive layer has a fracture phenomenon such as cracking or peeling. There is a problem that deformation such as warpage occurs. Furthermore, these adhesives lack insulation at high temperatures.

  In addition, silicone resin is remarkably deteriorated at a high temperature around 200 ° C., and the adhesive force is lowered, making it difficult to use.

  Furthermore, since a small amount of low molecular weight siloxane remains in the silicone resin, and the low molecular weight siloxane volatilizes to generate cyclic siloxane, the following problems arise. In other words, in the electrical and electronic fields that employ silicone resin adhesives, this cyclic siloxane adheres to the surface of electrical contacts such as terminals and becomes an insulating film, resulting in contact failure, causing poor conduction and malfunction. There's a problem.

  The present invention has been made in view of the above-mentioned problems, and has a composition having both high heat-resistant adhesiveness and insulating properties, and the amount of low-molecular siloxane remaining is extremely small or not contained at all. It is an object of the present invention to provide an adhesive structure having an adhesive layer made of an adhesive having a main component, and an adhesive film made of the adhesive.

  The present invention provides an adhesive layer comprising an adhesive mainly composed of a composition obtained by subjecting a mixture having a silicate compound and polydimethylsiloxane having a terminal silicate-modified polydimethylsiloxane to a hydrolysis reaction and a condensation reaction. The present invention relates to an adhesive structure characterized by adhering a material to be bonded.

First, the adhesive which adhere | attaches a pair of to-be-adhered material concerning this invention is demonstrated.
This adhesive mainly contains a composition obtained by subjecting a silicate compound and a polydimethylsiloxane having a silicate-modified end to a hydrolysis reaction and a condensation reaction.
Hereinafter, polydimethylsiloxane is abbreviated as “PDMS”, and polydimethylsiloxane whose terminal is silicate-modified is abbreviated as “modified PDMS”.

(Silicate compound)
The silicate compound of the present invention is an oligomer of a metal alkoxide made of silicon (Si), having a siloxane (-Si-O-Si-) skeleton in the main chain and introducing an alkoxy group (RO) in the outer chain. It is a compound. Here, (R) which is the alkyl part of the alkoxy group (RO) is exemplified by a methyl group, an ethyl group, a propyl group, and the like. This silicate compound has the property of easily reacting with water.

  Since the silicate compound is an oligomer of a metal alkoxide, it has a higher molecular weight than the metal alkoxide, and is therefore less likely to volatilize. For this reason, when the silicate compound is hydrolyzed, volatilization of the low-molecular siloxane having high volatility contained in the modified PDMS can be further suppressed. Moreover, the silicate compound has high chemical reactivity, and can smoothly advance the condensation reaction.

  Examples of the silicate compound used in the present invention include TEOS (tetraethoxysilane), methyl silicate, ethyl silicate, propyl silicate, and the like. Ethyl silicate is preferred from the standpoints of quality stability and safety. In the case of using methyl silicate for the purpose of increasing the reactivity, it is necessary to reliably carry out the treatment of volatile methanol.

(Modified PDMS)
The modified PDMS of the present invention is obtained by modifying the end of PDMS with a silicate compound, PDMS having silanol groups at both ends, and an alkoxy group that is a hydrolyzable functional group on one or both sides of the main chain. What is obtained by making it react with the alkoxysilane partial condensate which has this.

  This modified PDMS has a much higher functional group concentration than ordinary PDMS. Further, since the modified PDMS has high condensation reactivity with the silicate compound, the alkoxysilane partial condensate contained in the modified PDMS can be smoothly polymerized by being subjected to a condensation reaction smoothly.

  As the modified PDMS used in the present invention, those having a mass average molecular weight in the range of 5000 to 100,000 are used.

(Adhesive generation)
In the present invention, the adhesive mainly comprises a composition obtained by subjecting a mixture having the above-described silicate compound and the above-described modified PDMS to hydrolysis and condensation.

Since the silicate compound is easily hydrolyzed in the presence of water, the alkoxy group in the molecule of the silicate compound becomes a highly reactive silanol group (—OH group).
On the other hand, the modified PDMS is also hydrolyzed to form a silanol group (also referred to as “silanol modification”) due to the presence of water.

  Since both of these silanol groups have high reactivity and at the same time have similar reactivity, aggregation of silanol is caused by hydrolyzing the mixture containing the silicate compound and the modified PDMS. The condensation reaction with the modified PDMS proceeds smoothly without being accelerated. Thereby, the low molecular weight siloxane contained in the modified PDMS is also taken into the reaction product (composition).

In other words, the low molecular weight siloxane becomes a part of the material constituting the composition by the hydrolysis reaction and the condensation reaction, and does not exist as a simple substance, or the amount existing as a simple substance is very small (the valence of the siloxane is up to 15). ) For this reason, the low molecular weight siloxane does not volatilize from the composition, or the volatilization amount becomes extremely small.
An additive etc. can be mixed with this composition as needed.

(Adhesive material)
The pair of materials to be bonded is generally a synthetic resin, metal or ceramic.

  Examples of the adhesive material used in the present invention include epoxy resin, silicone resin, polystyrene (PS), high impact polystyrene (HIPS), polyvinyl chloride (PVC), polyamide (PA), polyester (PE), and polyacetal ( POM), polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polysulfone (PSF), polyethersulfone (PES), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyarylate (PAR) , Polyetheretherketone (PEEK), polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polyaminobismaleimide, methylpentene copolymer (TPX), cell Synthetic materials such as acetoacetate (CA), amorphous polymer, polyaminobismaleimide, bismaleimide-triazine thermosetting aromatic polyimide, urea resin, melamine resin, phenol resin, organic materials such as wood, plywood and wood fiber board, machinery Structural carbon steel, alloy steel, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, aluminum chrome molybdenum steel, austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, copper and copper alloys, gold silver and their alloys, Metal materials such as metals surface-treated with dissimilar metals, simple oxide alumina, magnesia, beryllia, zirconia, silicate silica, holsterite, steatite, zircon, double oxide aluminum titanate , Sialon, nitride nitride Containing, titanium nitride, carbide, boride-based ceramic materials such as silicides system, glass, ceramics, concrete and the like, the adhesive of the present invention are any useful adhesion with the adherend.

(Manufacturing method of adhesion structure)
The adhesive material having the composition as a main component is applied to one or both adhesive surfaces of the pair of adherends, and if desired, the adhesive surfaces of the pair of adherends via a predetermined thickness interval Overlap each other.

  Next, since the adhesive is in a liquid state (also referred to as “sol”), when the adhesive is formed as an adhesive layer, the adhesive is heat-treated at a temperature of usually 200 ° C. or higher by a drying and firing treatment, By curing, an adhesive layer is formed.

  In order to achieve the above-mentioned object, after applying the adhesive to the adhesive surface of the adherend, the silicate compound and the terminal are silicate-modified by heating at a temperature of usually 200 ° C. to 250 ° C. and leaving it for a predetermined time. The hydrolysis reaction and condensation reaction of the mixture having the polydimethylsiloxane proceeded to such an extent that the adhesiveness is not lost, and part or all of the volatile components of the mixture is volatilized to form a cured adhesive layer. desirable.

  And by adhering the said adhesive material and shape | molding an adhesive layer, to-be-adhered materials are adhere | attached and an adhesion structure can be provided.

  The use of a high-temperature furnace (also referred to as “oven”) is generally used as a drying and baking treatment for heat-curing the adhesive.

  The method for applying the adhesive is not particularly limited, but in general, it is desirable to use a coating apparatus that can apply the adhesive quantitatively.

The silicate compound is
[Chemical Formula 1] SinO (n-1) (RO) 2 (n + 1) (R = alkyl group, n = 4 to 16)
The modified PDMS is represented by [Chemical Formula 2] SinO (n-1) (RO) 2 (n + 1) (OSi (CH3) 2) m (RO) 2 (n + 1) SinO (n-1) (R = alkyl group, n = 4 to 16, m> 50).

  Moreover, it is preferable that the mixing | blending ratio of the said silicate compound (A) and the said modified | denatured PDMS (B) is the range of 0.1-10, in the molar ratio of A / B. The optimum blending ratio is around 1 in terms of A / B molar ratio.

  The composition contained in the adhesive according to the present invention is based on the ratio of the optimum blend. When the flexibility is required, the modified PDMS (B) is increased. On the contrary, the silicate compound is required when high hardness is required. (A) should be increased.

  However, in the composition, when the silicate compound (A) is increased, if the molar ratio exceeds 10, the volatile component of low-molecular siloxane increases. That is, since the amount of low molecular weight siloxane as a simple substance increases, problems such as shrinkage and thinning during curing and occurrence of cracks in some cases occur, and the effects of the present invention are not achieved.

  On the other hand, when the molar ratio is less than 0.1, the hydrolysis reaction and condensation reaction of the silicate compound (A) and the modified PDMS (B) are not performed smoothly, resulting in an uncured state and low molecular weight siloxane. It remains, and the effect of the present invention is not achieved.

  The silicate compound is preferably a trimer to a 12-mer (a trimer to a 12-mer). This is because, if it is less than a trimer, the effect of the properties of the silicate is small, and the viscosity of the silicate compound above that of the 12-mer is high, which makes it difficult to handle at the time of synthesis.

  Moreover, when the said composition is measured by a gas chromatograph (GC-MS) at 260 degrees C or less, it is suitable that a valence 15 or less siloxane is not included.

(Formation of adhesive film)
Further, in the present invention, the adhesive is applied to the surface of the releasable substrate, and the condensation reaction is carried out at room temperature or by heating, and part of the adhesive is volatilized to be semi-cured in a semi-cured state. It can also provide as an adhesive film obtained by forming an adhesive layer and peeling off the semi-cured adhesive layer from the surface of the releasable substrate.

  The releasable substrate used in the present invention is not particularly limited, and a substrate having releasability and a release treatment are applied to an adhesive film (semi-cured adhesive layer) formed from an adhesive. Any substrate may be used.

First, in order to form an adhesive film (semi-cured adhesive layer) from the adhesive, the adhesive is applied to the surface of a glass tray as a releasable substrate, and is usually 120 ° C. in an oven as a drying and firing treatment. The adhesive film is formed by heat treatment at the above temperature and curing.
The method of applying the adhesive used here and the drying and firing treatment as described above may be generally used in completing the present invention, and are not limited to this mechanism. Needless to say.

  In order to achieve the above-mentioned object, after applying an adhesive to the surface of the glass tray, it is usually heated in an oven at a temperature of 120 ° C. to 150 ° C. and left for a predetermined time of 2 to 3 hours. The hydrolysis reaction and condensation reaction of the mixture having the silicate compound contained and the polydimethylsiloxane having a terminal silicate modified are advanced to the extent that the adhesiveness is not lost, and the semi-cured adhesive layer (adhesive film) in a semi-cured state It is desirable to form.

  That is, the semi-cured state is a state in which a part or all of the volatile components of the composition contained in the semi-cured adhesive layer is volatilized and the condensation reaction is advanced, and the semi-cured adhesive layer is completely bonded. It means a state where it can be bonded without losing its sex. The standing time in this case is influenced by the temperature applied, but is usually about 10 minutes to 10 hours, and the semi-cured adhesive layer in a semi-cured state obtained under these conditions contains 5% by mass or less of volatile components such as a composition, It is contained in an amount of 0% by mass or more, and the semi-cured adhesive layer (adhesive film) is in a state of having adhesiveness.

  The shape of the adhesive film may be any shape as long as it can be placed on the bonding surface of the material to be bonded and can be bonded, but is generally formed into a sheet shape or a plate shape. The cured state of the adhesive film is preferably semi-solid (also referred to as “semi-cured” or “gel”).

(Adhesive film adhesion method)
The adhesive film (semi-cured adhesive layer) formed into a sheet shape as described above is fixed (held) by adhering or adhering to one or both adhesive surfaces of the pair of adherends, and if desired, predetermined The bonding surfaces of the pair of materials to be bonded are overlapped with each other through the thickness interval.

Next, the pair of materials to be bonded to which the adhesive film (semi-cured adhesive layer) is bonded,
The adhesive film (semi-cured adhesive layer) is formed as an adhesive layer by heating and curing at a temperature of usually 200 ° C. or higher by an oven as a drying and firing process.

  Then, by curing the adhesive film included in the adherend and forming it as an adhesive layer, the adherends are bonded to each other, and an adhesive structure can be provided.

  That is, the adhesive film is placed on one or both adhesive surfaces of a pair of adherends, and in this state, the adhesive surfaces of the pair of adherends are overlapped, and the adhesive film is heat-cured and bonded. By this, it is the adhesion method of the adhesive film which can provide an adhesion structure.

  Silicone resins that have been used as adhesives have become turbid and yellowish brown due to deterioration over time, and in the case of adhesives mainly composed of epoxy resins, they are brown and blackish brown. It was difficult to find foreign matter adhering to the surface. However, since the adhesive according to the present invention does not deteriorate over time and is always colorless and transparent, it is easy to find foreign matter.

In addition, a small amount of low molecular weight siloxane remains in the conventional silicone resin, and when the silicone resin is heated at a high temperature by reflow or the like, the siloxane is volatilized, and the flexibility and adhesiveness of the silicone resin are increased. It was damaged.
However, the adhesive layer formed from the adhesive according to the present invention does not contain low-molecular siloxane, or the amount existing as a single siloxane is very small (the valence of siloxane is up to 15). Boils and bubbles are less likely to occur in the adhesive, and the flexibility and tackiness are not impaired, and the effects of being resistant to aging are obtained.

  The adhesive layer made of the adhesive of the present invention and the adhesive film made of the adhesive have heat resistance that can withstand a high temperature range of 200 ° C. or higher, good insulation, and flexibility. The stress is easily relieved with respect to the deformation of the adhesive, does not show a fracture phenomenon such as cracking or peeling, and is relatively inexpensive.

  The present invention has an adhesive layer composed of an adhesive mainly composed of a composition that has both high heat-resistant adhesiveness and insulating properties, and has little or no residual low-molecular-weight siloxane. It is an object of the present invention to provide an adhesive structure and an adhesive film made of the adhesive.

It is a whole lineblock diagram showing the power module which has the adhesion structure concerning the present invention. Example 1 It is the block diagram which showed the experiment jig | tool. Example 1

Examples for more specifically explaining the present invention will be described below.
In addition, this invention is not limited at all by these Examples. In the examples and comparative examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

  The present invention is described in detail below.

[Adhesive structure]
In the first embodiment, an example of an adhesive structure employed as a part of a power module, which is applied to a vehicle such as an electric vehicle (hybrid car) having an electric motor as a part of a drive source, will be described.

  The power module is a structure that has a function of controlling the power supplied to the electric motor according to the driving state of the vehicle, which is mounted on the hybrid car described above. As shown in FIG. 1, the structure of the power module 1 includes a semiconductor element P called an IGBT (Insulated Gate Bipolar Transistor) that controls electric power supplied to the electric motor, and a semiconductor element P in the lower surface direction of the semiconductor element P. The aluminum plate 2 as the heat sink 2 having a rectangular shape that is long in the front-rear direction, which efficiently dissipates heat generated from the element P and keeps the temperature below a predetermined temperature, and a space in the front-rear direction on the upper surface of the heat sink 2 The warping of the heat sink 2 caused by the difference in the linear expansion coefficient between the adhesive layer 3 formed of the adhesive film of the present invention bonded to the semiconductor element P and the adhesive layer 3 and the heat sink 2 The restraint plate 4 to be restrained, the heat sink 5 as the radiation fin 5 joined to the surface of the restraint plate 4 opposite to the side joined to the heat sink 2, and the lower surface of the heat sink 2 so as to cover the heat sink 5 Solid And a cooling jacket 6 which is.

[Heatsink]
The heat sink 2 is made of a highly heat conductive material such as aluminum or copper (including a copper alloy; hereinafter the same), here, aluminum.

[Restraining plate]
The restraint plate 4 may be made of any material as long as the linear expansion coefficient and Young's modulus are about the same as those of the adhesive layer 3, and is made of ceramics, invar alloy, electromagnetic soft iron, or the like. When formed from ceramics, aluminum oxide, aluminum nitride, silicon nitride or the like is used. However, the constraining plate 4 is preferably made of the same material as that of the adhesive layer 3 and has the same thickness as the adhesive layer 3.

  Further, the restraint plate 4 is disposed symmetrically with respect to the adhesive layer 3 with the heat sink 2 interposed therebetween. Furthermore, the same number of constraining plates 4 as the adhesive layer 3 may be used, or a smaller number of constraining plates 4 than the adhesive layer 3 may be used across the plurality of adhesive layers 3. In the former case, it is preferable to use a rectangular constraining plate 4 whose dimensions in the front-rear direction and the left-right direction are substantially the same as those of the adhesive layer 3. In the latter case, the horizontal dimension is substantially the same as that of the adhesive layer 3, and the longitudinal dimension is substantially the same as the distance between the front edge of the front adhesive layer 3 and the rear edge of the rear adhesive layer 3. It is preferable to use the restraining plate 4.

  The heat sink 5 is made of a highly heat conductive material such as aluminum or copper, here aluminum, and has a corrugated shape including a wave crest part, a wave bottom part, and a connecting part that connects the wave crest part and the wave bottom part. The top plate and the wave bottom are brazed to the constraining plate 4 with the length direction of the top and the wave bottom being directed in the front-back direction. When a plurality of restraint plates 4 are brazed to the heat radiating plate 2, the same number of heat sinks 5 as the restraint plates 4 are brazed to the respective restraint plates 4, and there are fewer heat sinks 5 than the restraint plates 4. There is a case where it is brazed across a plurality of restraining plates 4.

  The cooling jacket 6 has a box-like shape as a whole, and a heat radiating fin housing portion 11 that is surrounded by the peripheral wall 9 and that opens upward is provided therein. A cooling liquid inlet pipe (not shown) is connected to the front wall portion of the peripheral wall 9 of the cooling jacket 6, and a cooling liquid outlet pipe (not shown) is connected to the rear wall portion so as to communicate with the inside of the radiation fin housing portion 11. Connected by such as.

  A plurality of screw holes 14 are formed in the left and right wall portions of the cooling jacket 6 at intervals in the front-rear direction. And the peripheral part of the heat sink 2 is mounted on the peripheral wall 9 of the cooling jacket 6, and the cooling jacket 6 is made to heat sink 2 by screwing the external screw 15 (fastener) which penetrated the heat sink 2 in the screw hole 14. Thus, the upper end opening of the radiating fin housing portion 11 is closed by the radiating plate 2 in a state where the heat sink 5 is accommodated in the radiating fin housing portion 11.

Although not shown, the space between the lower surface of the peripheral portion of the heat sink 2 and the upper end surface of the peripheral wall 9 of the cooling jacket 6 is sealed in a liquid-tight manner by a known appropriate sealing means such as an O-ring or a gasket. Yes. Therefore, the coolant sent from the inlet pipe flows rearward through the radiating fin housing portion 11 in the cooling jacket 6 and is sent out from the outlet pipe.
[Adhesive film]
Next, the manufacturing method of the adhesive film which concerns on this invention is demonstrated.
First, the production | generation of the composition which makes the main component of an adhesive film is demonstrated below. Incidentally, the adhesive layer is formed by subjecting an adhesive film to main baking and curing.

(Production of composition)
The composition according to the present invention is obtained by subjecting a mixture having a silicate compound and a polydimethylsiloxane having a silicate-modified end to a hydrolysis reaction and a condensation reaction. First, the manufacturing method of this composition is demonstrated concretely below.

In a reaction vessel equipped with a stirrer, a thermometer and a dropping line, 1.0 g of ethyl silicate (manufactured by Tama Chemical Co., Ltd., silicate 40 n = 4 to 6 or silicate 45 n = 6 to 8) and ethyl silicate 32.0 g of alkoxy-modified polydimethylsiloxane (mass average molecular weight; equivalent to 32,000) (HBSIL039 manufactured by Arakawa Chemical Co., Ltd.) was added to the terminal, and the mixture was stirred and mixed in the atmosphere (room temperature) for about 30 minutes. A raw material liquid A was obtained.
Here, silicates having the same type and the same characteristics were used as silicates used in ethyl silicate and polydimethylsiloxane obtained by alkoxy-modifying ethyl silicate at both ends.

Then, in the hydrolysis step and the condensation step, the raw material liquid A was added dropwise with a required amount of 0.93 g of water over about 1 hour and stirred and mixed.
Then, it naturally cooled to room temperature over about 30 minutes, stirring, and obtained the composition (adhesive).

[Formation of adhesive film]
Since the adhesive is in liquid form (also referred to as “sol”), in order to form an adhesive film from an adhesive, the adhesive is applied to a tray such as a mold, and is applied by a drying and firing process. It is also called “semi-cured” or “gel”.

  The adhesive is uniformly applied to a tray such as a mold so as to have a final thickness of 200 μm, and then placed in a high temperature furnace (also referred to as “oven”) DRC433FA manufactured by Advantech Toyo Co., Ltd. at 120 ° C. 3 Dry baking treatment was performed for a time, the adhesive was cured, and the adhesive film was completed.

[Manufacturing method of power module]
The power module base 1 is manufactured as follows.
That is, the heat radiating plate 2 is laminated on the surface side where the adhesive layer 3 is provided, the restraint plate 4 is laminated on the surface of the heat radiating plate 2 opposite to the adhesive layer 3, and the heat radiating plate 2 on the restraint plate 4 is opposite to the heat radiating plate 2. The heat sink 5 is disposed on the side surface. Between the heat sink 2 and the restraint plate 4 and between the restraint plate 4 and the heat sink 5, sheet-like aluminum brazing materials made of Al—Si alloy, Al—Si—Mg alloy, etc. are interposed, respectively. Keep it.

  Next, the heat sink 2, the restraint plate 4 and the heat sink 5 are temporarily fixed by appropriate means, and heated to 570 to 600 ° C. in a vacuum atmosphere or an inert gas atmosphere while applying an appropriate load to the joint surface. Thus, the radiator plate 2 and the restraint plate 4 and the restraint plate 4 and the heat sink 5 are brazed simultaneously. Thereafter, the cooling jacket 6 is fixed to the heat sink 2. So far, it will be completed as a base for power modules.

  A film-like FPC [flexible printed wiring board (not shown) for wiring the semiconductor film P, which is a material to be bonded, to the electric motor provided in the hybrid car vehicle, the adhesive film (semi-cured adhesive layer). )] And the adhesive surface of both the upper surface of the aluminum flat plate 2 as the heat radiating plate 2 of the power module base, and are fixed (held) in close contact with each other. Then, the bonding surfaces of the materials to be bonded are overlapped.

  Next, the pair of adherends to which the adhesive film is bonded are heat-treated (mainly fired) at a temperature of usually 200 ° C. or higher by an oven as a drying and firing process, and cured to form an adhesive film (half-finished). The cured adhesive layer) is formed as an adhesive layer, and the adherends are bonded to each other. Then, the semiconductor element P is mounted on the upper surface of the bonded FPC and is joined by soldering. Thus, the power module is manufactured.

  In the said Embodiment 1, although the adhesive film is used as adhesive joining of FPC and the heat sink 2, it replaces with this and you may bond using the adhesive material of this invention.

[Evaluation 1 Measurement of volatilization of low molecular siloxane]
(Measurement specimen sheet)
The above composition was poured into a petri dish (diameter 103 mm) to a final thickness of 1 mm, and dried in a high temperature furnace (also called “oven”) DRC433FA manufactured by Advantech Toyo Co., Ltd. at 200 ° C. for 2 hours. After baking, the mold was removed from the petri dish to obtain a measurement specimen sheet (diameter 103 mm, thickness 1 mm).

(silicone rubber)
In addition, as a conventional silicone resin to be compared, a silicone rubber mainly composed of a silicone resin is adopted, and a commercially available SR-50 manufactured by Tigers Polymer Co., Ltd. is adopted, and a sheet having a diameter of 103 mm and a thickness of 1 mm. It was created.

(Evaluation equipment)
In order to measure the remaining amount of cyclic siloxane which is a volatile component of low-molecular-weight siloxane, an evaluation apparatus is a cooled injection system (Gerstel) of a thermal desorption unit (hereinafter referred to as “TDU”). Hereinafter, it was abbreviated as “CIS”.) A gas chromatograph mass spectrometer (Gas Chromatography Mass Spectrometry (hereinafter abbreviated as “GC-MS”)) was used. The GC-MS apparatus is a 5975B system manufactured by Agilent Technologies.

(Evaluation methods)
In order to vaporize the volatile components in the sample, heating was performed while flowing helium gas through the sample in the sample holder by TDU. And after making the outgas vaporized in helium adsorb | suck to the adsorption tube in a CIS unit, the outgas collected by the adsorption tube was flowed to GC-MS apparatus, and the kind and quantity of the volatile component were measured. The column of the GC-MS apparatus is a capillary column (liquid layer: phenylmethylsiloxane).

(Details of measurement conditions)
The heating unit was heated by TDU at 160 ° C./min from 40 ° C. to 200 ° C. (hold time 5 minutes), and mass spectrometry was performed through an inert capillary tube (temperature: 350 ° C.).

The GC-MS apparatus has an inlet temperature of −150 ° C. to 12 ° C./second to 325 ° C., and a column of Agilent.
19091S-433 (column length 60 m, column inner diameter 0.25 mm, column film thickness 0.25 μm), oven: 40 ° C. to 25 ° C./min to 300 ° C. (hold time 10 minutes), helium flow rate: 1.2 mL / min, MS Ion source temperature 230 ° C .: MS quadrupole temperature: 150 ° C., MS ionization voltage: 69.9 eV), scan range: m / z 100-1000
It is. Here, MS is an abbreviation for Mass Spectrometry.

(Evaluation results)
The evaluation results are shown in Table 1. This Table 1 classifies the volatile components in the valence range of D3 to D15 siloxanes that are likely to volatilize at high temperatures of 150 ° C. or higher and 260 ° C. or lower, and summarizes the amount of each volatile component. .

  According to Table 1, when the measurement test piece sheet made of the composition according to the present invention is compared with the conventional silicone rubber, the conventional silicone rubber shows the volatilization of the cyclic siloxane at a valence of 3 to 15, It can be seen that the test specimen sheet shows no volatilization of the cyclic siloxane. That is, it can be seen that the low molecular weight siloxane does not remain in the composition according to the present invention (the siloxane having a valence of up to 15 is not included).

In Table 1, the vertical axis represents the volatilization amount, “0.00E + 00” means 0.00 × 10 ^0, that is, 0, and “3.50E + 08” means 3.50 × 10 ⁸ .
The volatilization amount is expressed as a peak area, and the unit is Counts (abbreviated as “ct”). The horizontal axis is the valence of cyclic siloxane.

[Evaluation 2 Heat-resistant adhesive strength test]
(Measurement specimen S)
Each of the above-described compositions was applied to each bonding surface (area 20 mm × 15 mm = 300 mm ² ) of a pair of materials to be bonded, each being an aluminum plate (length 80 mm, width 20 mm, thickness 2 mm) to a thickness of 100 μm. These were used as measurement test pieces, pre-heated at 120 ° C. for 60 minutes, and then pre-cured (pre-treatment stage firing) at 200 ° C. for 3 hours. The composition coating thickness after precure was 40 μm.

  A pair of adhesive surfaces (composition application surfaces) of the above pre-cured measurement test pieces are overlapped with each other at an interval of 80 μm thickness, and tightened with a tightening jig at a pressure of 5 N / cm and subjected to main firing at 250 ° C. for 5 hours. went. After the main baking, the test piece S was left at room temperature for 30 minutes or more. The thickness of the adhesive layer is 40 × 2 = 80 μm.

(Comparative Example 1)
Further, as a conventional silicone resin to be compared, Super X Clear (product number AX-041, manufactured by Cemedine Co., Ltd.) was used as a representative silicone resin adhesive. The same aluminum plate as described above was used as the adherend, and the thickness of the adhesive applied to the adherend and the area of the adhesive surface were the same as those of the measurement test piece. That is, the adhesive material was applied to each of the pair of surfaces to be bonded in a thickness of 40 μm and allowed to stand for 10 minutes, and then the adhesive surfaces were overlapped with an interval of 80 μm thickness, and a pressure of 5 N / cm was applied by a clamping jig. The silicone resin test piece was completed by allowing it to stand at room temperature for 24 hours in the clamped state.

(Comparative Example 2)
As a typical epoxy resin, High Super 30 (Cemedine, product number CA-193) was used. The main components of the adhesive are A liquid: 100% epoxy resin and B liquid: 100% polythiol. After sufficiently mixing the same amount of both A and B solutions in a volume ratio, each was applied to a pair of surfaces of a material to be bonded, which is an aluminum plate, to a thickness of 40 μm and allowed to stand for 10 minutes. The epoxy resin test piece was prepared by applying heat treatment at 100 ° C. for 10 minutes after being allowed to stand at room temperature for 24 hours while being overlapped at intervals and tightened at a pressure of 5 N / cm with an attaching jig.

(Evaluation methods)
A heat-resistant adhesive strength test was performed on the measurement test piece S, the silicone resin test piece of Comparative Example 1, and the epoxy resin test piece of Comparative Example 2. As a heat-resistant adhesive strength test, the adhesive strength before and after the test in a storage test at 200 ° C. for 500 hours was measured. As the adhesive strength, a tensile shear test (JIS) was performed at normal temperature on each measurement specimen using an autograph AGS-J 5kN tensile tester manufactured by Shimadzu Corporation.
K 6831). Furthermore, the presence or absence of the adhesive layer fracture | rupture was investigated in the 200 degreeC 1 hour->-196 degreeC 10-minute cold-heat repeated test. The results of the heat-resistant adhesive strength test are shown in Tables 2-3.

(Evaluation results)
The evaluation results are shown in Tables 2-3. From Table 2, the measurement test piece S has a slightly improved adhesive strength after the test in the storage test at 200 ° C. and 500 hours than before the test, but Comparative Example 1 (silicone resin test piece) has a large adhesion. The strength decreased, and Comparative Example 2 (epoxy resin test piece) had an adhesive strength of 0 due to the destruction of the adhesive layer. The mass reduction rate after storage at 200 ° C. for 500 hours is also lower for the measurement test piece S than the test pieces of Comparative Example 1 and Comparative Example 2, and the test piece of Comparative Example 1 is overwhelming with a mass reduction rate of 42%. Big. Further, in the cold and hot repeated adhesion test, the measurement specimen S did not break the adhesive layer even after repeated 50 times. However, in the specimen of Comparative Example 1, the test of Comparative Example 2 was only 3.8 times. In the piece, the adhesive layer was broken only by being placed at a low temperature without repeating.

  Further, from Table 3, there is no particular difference in the shear adhesive strength when the test temperature is 0 ° C. for the measurement test piece S, the silicone resin test piece of Comparative Example 1 and the epoxy resin test piece of Comparative Example 2. From the test temperature of 50 ° C. or higher, the adhesive strength of the measurement specimen S is almost unchanged, whereas the adhesive strength of the test specimen of Comparative Example 1 and the specimen of Comparative Example 2 is drastically decreased. I understand that. That is, it turns out that the measurement test piece S is excellent in heat resistance.

In Table 2, the unit of tensile shear (shear) force was “N / mm ² ”, and the unit of mass reduction rate was “%”. In Table 3, the vertical axis represents shear (shear) adhesive strength, the unit is “Mpa” (megapascal), the horizontal axis represents temperature, and the unit is “° C.”.

[Evaluation 3 Insulation test]
(Measurement specimen V)
The above composition was poured into a petri dish (diameter 103 mm) to a final thickness of 250 μm and dried in a high temperature furnace (also called “oven”) DRC433FA manufactured by Advantech Toyo Co., Ltd. at 200 ° C. for 2 hours. After baking, the mold was removed from the petri dish to obtain a measurement specimen V (diameter 103 mm, thickness 40 μm). Five test specimens V were prepared.

(Evaluation methods)
An insulation test was performed on the measurement specimen V. As the insulation test, the measurement was performed based on the dielectric strength (dielectric breakdown voltage) measurement (JIS C2110) as JIS standard. Further, at the fixed time, a short-time breakdown method is employed, and a breakdown measurement is obtained when the voltage is increased from 0 to 5 kv at a constant speed at which dielectric breakdown occurs in an average of 10 seconds.
The experimental jig is configured as shown in FIG. The measurement specimen V is sandwiched between electrodes and placed in a fluorine inert liquid (FC-72 Fluorinart manufactured by Sumitomo 3M Co., Ltd.) immersed in a test container. As the withstand voltage tester, TOS5050A manufactured by Kikusui Electronics is used, and the voltage is increased to 0 to 5 kv.
The dielectric breakdown voltage (kv), the strength of dielectric breakdown strength (kv / s), and the withstand voltage indicating the ability of the solid electrical insulating material to withstand the voltage are measured.

(Evaluation results)
From the evaluation results, V5 measurement test pieces were able to withstand the voltage up to a withstand voltage of 4 to 5 kv. That is, it has an insulating property.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto, and can be recognized by those skilled in the art from the description of the claims, the specification, and the drawings. Modifications, deletions, and additions are possible without departing from the technical idea of the present invention.

  In Example 1 described above, silicates having the same type and the same characteristics were used as ethyl silicate and silicate used in polydimethylsiloxane obtained by alkoxy-modifying ethyl silicate at both ends. In this case, since they have similar reactivity, the reaction rate is about the same, which is preferable.

  However, the present invention is not limited to this, and silicates of different types and characteristics (for example, when using ethyl silicate and methyl silicate, when using ethyl silicates having different purity) may be used. . In this case, since a difference occurs between the reaction rates, it is necessary to adjust the synthesis time to make the reaction rates the same and to change the manufacturing conditions.

  A high-temperature furnace (also referred to as “oven”) is generally used as a drying and baking treatment for heat-curing the composition. However, a curing method in which a curing agent is mixed with the composition without requiring an oven may be used.

  In Example 1 described above, after applying the composition to the adherend, regarding the initial heating when performing the drying and firing treatment, the temperature in the heater such as an oven is set to the adherend to which the composition is applied. It is desirable that the temperature is set to a sufficiently high temperature before charging the material, and the material to be bonded is applied to the heater, and rapid heating is performed from the beginning. Thereby, the dispersion | variation in the characteristic of the to-be-adhered material which has the said composition can be minimized.

  Moreover, you may use a silane coupling agent for the said composition with the said modified | denatured PDMS as needed.

  Examples of the silane coupling agent include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, and dipropyl. Dialkyl dialkoxysilanes such as dimethoxysilane, dipropyldiethoxysilane, dipropyldipropoxysilane, dipropyldibutoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldibutoxysilane, N-hexyltri Methoxysilane, N-hexyltriethoxysilane, N-octyltriethoxysilane, N-decyltrimethoxysilane, phenyltrimethoxysilane Phenyltriethoxysilane, diphenyl trimethoxysilane, alkyltrialkoxysilane such as diphenyl silane, vinylsilane, .gamma.-methacryloxypropyltrimethoxysilane polymerizable silane coupling agent such as and the like. When the silane coupling agent is added, the flexibility and adhesiveness of the adhesive layer are improved.

  Further, it is desirable that a filler is mixed in the adhesive layer, and the filler is preferably a metal nitride and / or a nitride metal and / or a metal oxide and / or an oxide metal.

  As the filler used above, there are mainly fine particles of metal, metal oxide, metal nitride and metal carbide. Specific examples of the filler include metal powders such as copper, aluminum, silver, and stainless steel, aluminum oxide, tin oxide, zinc oxide, nickel oxide, titanium oxide, silicon oxide, vanadium oxide, cerium oxide, Oxidation of metals or similar metals such as copper oxide, iron oxide, silver oxide, or nitriding of metals or similar metals such as aluminum nitride, boron nitride, silicon nitride, chromium nitride, tungsten nitride, magnesium nitride, molybdenum nitride, lithium nitride And fine particles of metal such as silicon carbide, zirconium carbide, tantalum carbide, titanium carbide, iron carbide and boron carbide, or carbides of similar metals. The particle shape of the filler may be spherical, flaky, or needle-shaped, but the average particle size is usually preferably in the range of 0.1 μm to 50 μm (by laser scattering method). The filler used in the present invention is preferably used as a mixture of two or more of the same or different types having different particle diameters. The difference in particle diameter of the filler is desirably 3 times or more. The fillers, particularly metal nitrides, nitride metals, metal oxides and oxide metals, improve the thermal conductivity, insulation and conductivity of the composition.

  Further, the adhesive of the present invention includes ferrite, a magnetic material containing rare earth elements, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, Inorganic filling of diatomaceous earth, dolomite, gypsum, talc, clay, mica, sepiolite, calcium silicate, bennite, white carbon, carbon black, iron powder, aluminum powder, stone powder, blast furnace slag, fly ash, cement, zirconia powder, etc. Materials, asbestos fibers, glass fibers, carbon fibers, ceramic fibers, metal fibers, rock wool, whiskers and other inorganic fibers, synthetic resins, rubbers, elastomers, and the like may be added.

  Examples of a method for applying the adhesive on the adhesion surface of the material to be bonded include a screen printing method, a doctor blade method, and a dip coating method. Prior to applying the composition onto the adhesion surface of the adherend, the adhesion surface may be degreased and washed in advance. Moreover, you may improve the adhesiveness of the contact bonding layer formed by primer-processing the said contact surface and a contact surface if desired.

Moreover, this invention can be grasped | ascertained as follows.
(Fifth invention)
A composition comprising as a main component a product obtained by subjecting a mixture having a silicate compound and a polydimethylsiloxane having a terminal silicate-modified polydimethylsiloxane to a hydrolysis reaction and a condensation reaction is used as one or both of a pair of adherends. Apply to the adhesive surface,
A bonding method in which the bonding surfaces of the pair of materials to be bonded are overlapped and heat cured to bond.

(Sixth invention)
The adhesive film according to the fifth aspect of the invention is placed on one or both adhesive surfaces of a pair of adherends, and the adhesive surfaces of the pair of adherends are superposed in this state, and the adhesive film is heated. A bonding method characterized by curing and bonding.

(Seventh invention)
The adhesion structure according to any one of claims 1 to 4, wherein the adhesion structure is provided in a power module applied to a vehicle such as an electric vehicle (hybrid car).

  The method and application device for applying the adhesive are not limited to this, and any method and means can be used as long as the adhesive can be applied.

  The adhesive structure and adhesive film according to the present invention have a composition having both high heat-resistant adhesiveness and insulating properties, and a composition containing little or no low-molecular-weight siloxane as a main component. An adhesive structure having an adhesive layer made of the adhesive material and an adhesive film made of the adhesive material can be provided.

DESCRIPTION OF SYMBOLS 1 ... Power module, 2 ... Heat sink (for example, aluminum flat plate), 3 ... Adhesive layer,
4 ... restraint plate, 5 ... radiating fin (for example, heat sink), 6 ... cooling jacket,
9 ... Peripheral wall, 11 ... Radiation fin housing part, P ... Semiconductor element (for example, IGBT)

Claims (5)

By an adhesive layer comprising an adhesive mainly composed of a composition obtained by subjecting a mixture having a silicate compound and a polydimethylsiloxane having a terminal silicate-modified polydimethylsiloxane to a hydrolysis reaction and a condensation reaction,
A bonded structure characterized by bonding a pair of materials to be bonded. The silicate compound is
[Chemical Formula 1] SinO (n-1) (RO) 2 (n + 1) (R = alkyl group, n = 4 to 16)
And
Polydimethylsiloxane having a silicate-modified terminal is
[Chemical Formula 2] SinO (n-1) (RO) 2 (n + 1) (OSi (CH3) 2) m (RO) 2 (n + 1) SinO (n-1)
(R = alkyl group, n = 4 to 16, m> 50)
It is represented by these, The adhesion structure of Claim 1 characterized by the above-mentioned. The silicate compound (A);
The blending ratio of the polydimethylsiloxane (B) having a silicate-modified terminal is as follows:
The adhesive structure according to claim 1 or 2, wherein the molar ratio of A / B is in a range of 0.1 or more and 10 or less.   4. The composition according to claim 1, wherein the composition does not contain a siloxane having a valence of 15 or less when measured by a gas chromatograph (GC-MS) at 260 ° C. or less. 5. Adhesive structure. Applying an adhesive comprising the composition according to any one of claims 1 to 4 to a releasable substrate surface,
While proceeding the condensation reaction at room temperature or heating, volatilize part of the adhesive to form a semi-cured adhesive layer in a semi-cured state,
An adhesive film obtained by peeling the semi-cured adhesive layer from the surface of the releasable substrate.