JPS58218710A - Thermoconductive electrically insulating sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat-conductive electrical insulating sheets used for heat-generating electrical components such as power transistors and iris resistors. be.

What is the heat dissipation insulation material for heat-generating electrical parts? However, since mica is hard, it has poor adhesion to heat-generating electrical parts and heat sinks.
In response to the trend of increasing thermal resistance.

For this reason, it is necessary to cover it with H51 thermal grease.

In recent years, thermal insulation materials that do not use thermal grease have been developed, such as solid silicone rubber with large amounts of fillers (alumina, quartz, boron nitride, magnesium oxide, etc.) that increase thermal conductivity. Heat dissipation insulating sheets with additives/j are known.

However, when processing such a heat dissipating insulating sheet, the rubber and filler are uniformly kneaded using a Banbury Miki 1-no or [1-ru], then formed into a sheet using an extruder or calender roll, and then (Crosslinking is done using a hot air oven or press. In this case, a large amount of filler is added to improve the thermal conductivity, but because the viscous of the mixed product is stiff, the 11-hole, screw , will wear out processing machines such as dies.In particular, alumino is effective in increasing heat conductivity, but since it has a hardness of 9, the thickness gap of the processing machine becomes thick 41b.

-/j, 1m sheet filled with 1n is tear resistant! The mechanical strength of the 1st class is weakened, and J
(Because it is easily damaged, it must be reinforced with glass cloth.)

Based on the above circumstances, we investigated a thermally conductive electrical insulating sheet made by coating a glass cloth with a composition C, which is a mixture of zero-weighted liquid silicone rubber and a filler that increases thermal conductivity, and curing it. is being done.

Such liquid silicone rubber has a lower viscosity than solid silicone rubber, and a large amount of thermally conductive filler can be added. Since there is no need for a processing machine such as this, it has excellent I fL.

However, when coating glass fli with a composition in which a filler is added to liquid silicone rubber, the glass cloth needs to have a certain degree of strength, and when coating the composition, it is difficult to apply the composition to the glass fabric. Pass it through the circle and put it on the back side of the kimono, and let it harden regardless of the size of the sheet! I-h Ei1. There is a problem of

The present invention has been made based on the above, and aims to provide a thermally conductive electrically insulating sheet that is superior to JL1 and has a uniform thickness. .

That is, the thermally conductive electrical insulation sheet I of the present invention has f=
Heat transfer to J-additional liquid silicone-rm39? 4.The composition part formed by adding a filler that increases the
50 pieces with a light density of 1 good in at least one direction, longer than m,
/ 25 mm 11J or more] There is a type C which is characterized by having a hardened coating.

In the present invention, JJI's f=I weighted wave-type liquid silicone rubber is defined as C1) diornoJnovo1nosi1.
Kirin (2J) A liquid A containing a small number of silicon-bonded hydrogen atoms in one molecule [11 Phosphorus (3) 4J addition reaction catalyst J, and the above components (1) is the main component, which is crosslinked by component (2) under the catalytic action of component (3) to form a rubber bullet (A).

tl In other words, the silicon atom j'-bonded 1-rukenyl group in component (1) and the water atom-bonded water atom r in component (2) undergo J, i=J polymerization due to the action of component (3). and cross-link, gol＼
A bullet body is formed.

In addition to the above components (1) and (3), viscosity modifier J3 and/or
'Alternatively, it is possible to mix a curing inhibitor.

The curing inhibitor C may be benzo-1 to linozole or a hydroperoxide compound.

Fillers used in the present invention that increase thermal conductivity include alumina, quartz, boron nitride, zinc oxide, calcium fluoride, etc., but alumina is preferable from the viewpoint of thermal conductivity and ease of handling. These fillers may be used alone or in combination of two or more.These fillers may be used as is or may be treated with a silane coupling agent or the like.
You can also use C.

The processed liquid silicone rubber and the thermally conductive filler are mixed by a method that is applied to liquid substances in the standard 7C, for example, in a stirrer 11', and the Banbury rubber used in ordinary rubber processing is mixed with the heat conductive filler. Mixers and [1-ru are unavoidable.

After the composition is coated on a glass cloth,
It is heated and hardened (formed into a sheet) in a normal hot air oven, infrared heater oven, etc.

In order for the above-mentioned sheet reinforced with glass 11C' to function as a heat dissipation sheet 1, the thermal conductivity of the cured composition must be 1.
It is preferable for IT to be on 8X 10' cat/cmsec LJ.

In addition, the thickness of the glass cloth used is GJ O, 03mm LJ
If the glass cloth is less than this, the strength of the glass cloth will be low and the glass cloth will have a strong tendency to break or tear when it is coated with the composition.

Furthermore, the thread density of Glass Zu b is 55 threads/2 mm l1
It is necessary to use more than 1 of these, and if C is less than this, the coating composition will penetrate through the meshes of A11 and adhere to the back side, and this will harden, resulting in non-uniformity in the sheet J9 thickness.

Generally, the composition is coated and cured on one side of the crow yarn.
(This is to avoid curing the coating on the other side, but if the cured product ends up adhering to the back side when curing the coating on the other side,
If the other side is coated, the coating will be 4J thicker due to the presence of the cured product, resulting in non-uniformity of the surface area.

In order to improve the adhesion of the glass cloth composition, the glass cloth is subjected to heat treatment (heat cleaning, heat treatment), and in addition, a silane cutting agent, a coupling agent, etc. C'primer surface treatment may be performed. If the mechanical strength of the glass 5 is particularly required, only the primer surface treatment may be performed without heat treatment.

The composition is coated on a glass cloth using the usual gluing method such as dipping, coating, coating, etc., and the composition of the present invention is particularly suitable for knife coating. It is dynamic.

Since the composition is a liquid, it may be coated as a undiluted solution (C), or it may be coated with an organic solvent (C) or diluted (C).

The attached drawing shows an example of coating and curing the composition on Glass IrJ.

A glass cloth (1j2) is supplied from the delivery device 1 with a brine treatment solution applied in a brine treatment device 3 and then dried in a heating furnace 4, and then one side of the glass cloth 2 is coated with a composition 6 by a knife yoke 5. , and is heated and hardened in a heating furnace 7 and wound up in a winding device 8.

In this way, the composition 6 is coated and cured on one side of the C glass RI 2, and the composition is coated and cured on the other side of the IJ receipt sheet with a knife, thereby completing the C sheet.

If oh, braai? The processing device 3 a3 and the heating furnace 1 may be omitted, or C pretreatment III! (heat cleaning, and -1- treatment) equipment is installed.
t) J.

Hereinafter, examples of the present invention will be explained in comparison with comparative examples.

Example 1 (1) 100 parts by weight of 4-phosphorus dimethyl borosilicate I, whose both ends were capped with dimethyl vinylsilyl groups (2)
Silanol groups blocked at both ends J Rubolisi [11 phosphorus (utilization regulator) 12 double part (3) Norlumina 2 O heavy part (4)
Both ends have trimebyl silyl groups and j-chain mebylhydrogen 1-'xane 2.0 parts (5) chloroplatinic acid solution of
J addition reaction catalyst) Type 1 opening (6) Benzotriazole 301 rβ (tail solution (hardening inhibitor)
Composition C was obtained by mixing 0.2 parts by weight until uniform. The thermal conductivity of the cured product of the composition is 2
There were 3X 10'cat,/cm'cscc'c.

This composition was applied to a glass substrate whose surface had been previously treated with N-β (amine ethyl)
] (thickness 0.10mm, light density iK 58 wood/'25
One side of C (mm medium x 57 wood/25 mm 1 l) was coated with Noifcoat and cured in an oven at 120°C, and then one side of C (l!!) was similarly coated and cured with tI.
C 0.20mm thick sheet f7k.

During the production of this sheet, there was no cutting of the crow 11'', and a sheet of uniform thickness was obtained.

The tensile strength of Sea 1~ is 5 K'j/mrM,
The thermal resistance in the case of the power transistor heat dissipation sveza To-3 was 0.60°C/WC.

Example 2 A glass cloth with a thickness of 0.03 mm whose surface was previously treated with N-β (amino del) γ-aminopropylmethoxysilane,
Thread density 60 / 25ml 1l JX 75 wood / 25mm
rll) was coated with the same composition as in Example 1 and cured in the same manner to obtain a sheet having a thickness of 0.15 mm.

In the production of Seat 1-, the glass cloth was not cut, and Seat 1- of uniform thickness was obtained.

The tensile strength of the sheet was 3 to 9/-, and the thermal resistance in the case of TO-3 was 0.50°C, /W-r.

Example 3 Heat cleaned C glass cloth, thickness 0.13mm,
Thread density: 50 threads / 25 mm width x 30 threads, /'25 mm
The same composition as in Example 1 was applied to both sides of the Fliti
, harden +'? Sa0, 25mm sheet for 19k
.

When manufacturing the sheet, there is no cutting of glass 1j;
A sheet of uniform thickness was obtained.

The tensile strength of Sea 1~ was 5 to 9/-, and the thermal resistivity of TO-3 was 0.70°C 7/W.

Example 4 Among the components of Example 1, j'lumina of (3) was 1801
A -C composition was obtained by mixing all the same components except for the fFi part. The thermal conductivity of the cured product of the composition is 18 x 10-
'cal/cm'C3ec.

This composition was coated and cured in the same manner as in Example 1 to obtain a sheet of 0.20 mm in thickness. A sheet was obtained.

The tensile strength of the sheet is 68! j/mA and To-
The thermal resistance in case No. 3 was 0.75° C./W.

Comparative Example 1 A glass cloth (thickness 0.0
2mm, yarn density 60 wood/25mm1lJ x 70 pieces/25mm1lJ) was coated with the same composition as in Example 1 in the same manner, lI! l! A sheet was obtained, but during production, the Karasui [I] was cut several times.

Comparative Example 2 A glass cloth whose surface was previously treated with N-β (amino-■del)γτ aminopropyltrimethyl-1-xysilane C had a thickness of 0.
10mm, thread density 45/25mm1lJ X30
The same composition as in Example 1 was coated and cured in the same manner as in Example 1 to obtain C sheet, but sheet 1 of uniform thickness was obtained.
- was not obtained.

J3, measurements of various characteristics are as follows.

Thermal conductivity: 5S-TC-18 type (manufactured by Shiba-dokuchi Gakukikai Seisakusho) was used.

The solvent used is benzene-azetone.

Thermal resistance: power transistor 2SD676 and thickness 3.
A thermally conductive electrical insulation sheet is inserted between 2mm copper plates.

Power] - Drive the transistor, measure the collector current and the voltage between the two-meter and one-meter transistor, and calculate the collector loss (w
a t'? ). Measure the coos temperature and fin humidity of the transistor at various collector losses.

The heat resistance (° C./W) between booths was determined from these cracks.

As explained above, the thermally conductive electrical insulating composition of the present invention has a low viscosity and is easy to coat, so it can be processed from Sea 1 to Sea 1 with simple equipment.

In addition, by selecting the thickness of the glass cloth and the thread density within a predetermined range, there is no need to cut the glass cloth when adding the sheet, and it is possible to obtain sheets of uniform thickness. becomes.

[Brief explanation of the drawing]

The attached drawing is crow 0. FIG. 6 is an explanatory diagram of an example of coating a cloth with a composition and curing it. 2 glass cloth, 3: primer treatment device, 5: knife coater, 6: composition, 7: heating furnace.

Claims (1)

[Scope of Claims] 1. A thermally conductive electrical insulating composition made by adding a filler to increase the conductivity of a liquid silicone rubber with a thickness of 0.03711111 or more and having a small ζ8 in one direction. A thermally conductive electrical insulating sheet characterized by being coated and cured on a glass cloth having a thread density of 50 threads/25 mm or more. 2. The polymerized liquid silicone rubber described above contains at least two silicon atoms in the molecule, a di-arganoborisilane 1-1 group having a j-linked alkenyl group, and at least two silicon A patent claim characterized in that the liquid organoborysilane containing atomically bonded hydrogen atoms is a component, and is cross-linked and cured under a J reaction catalyst to form a rubber elastic body. The thermally conductive electrical insulating sheet according to item 1.