JP2013103341A - Method for manufacturing glass cloth composite silicone rubber sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable simplification of manufacturing process, and significant reduction of cost, compared with a past glass cloth composite silicone rubber sheet, and improvement of the releasability to an anisotropic conductive film in the thermocompression bonding wiring connection process of electricity and an electronic equipment component compared with the thermally conductive silicone rubber sheet of a single layer.SOLUTION: Integral moulding is achieved by lapping over and setting up the glass cloth on a heated and cured silicone rubber sheet original fabric and in addition by coating and by heating and curing a silicone elastomer formation composition that can be cured by the hydrosilylation reaction on the glass cloth.

Description

  TECHNICAL FIELD The present invention relates to a method for producing a silicone rubber sheet reinforced with glass cloth, and particularly for thermocompression bonding used for the purpose of transferring heat and applying uniform pressure in the wiring connection process of electrical / electronic equipment components. The present invention provides a method for producing a glass cloth composite silicone rubber sheet capable of producing a silicone rubber sheet at a lower cost than before.

  When manufacturing a liquid crystal panel, an anisotropic conductive adhesive (paste or film) is used to connect the transparent lead electrode of the liquid crystal panel and the lead electrode of the flexible printed circuit board (COF) on which the driving LSI is mounted to drive the liquid crystal. And the like, and thermocompression-bonded via an electrical and mechanical connection. In this case, for the purpose of applying a uniform pressure together with heat, it is common to sandwich a silicone rubber sheet between the pressurizing / heating metal tool and the COF.

  In the thermocompression bonding step, it is performed to repeatedly feed the sheet a little after being crimped several times using the same location of the silicone rubber sheet. That is, being able to use as much of the same place of the silicone rubber sheet as possible leads to the advantage of manufacturing cost. Therefore, it is proposed to improve the strength of the sheet by laminating a heat conductive silicone rubber and a glass cloth (Patent Document 1: Japanese Patent No. 3902558). In addition, by combining glass cloth, deformation at the time of thermocompression bonding is suppressed, so there is also a report that it is advantageous for joining narrow pitch electrodes accompanying high definition (Patent Document 2: Japanese Patent No. 3244187). ). Furthermore, the heat conductive sheet containing a glass cloth is also developed for heat dissipation of heat-generating electronic components (Patent Document 3: Japanese Patent No. 3029556, Patent Document 4: Japanese Patent No. 2938340).

  However, these glass cloth composite silicone rubber sheets are integrally formed by always laminating an uncured silicone rubber on a glass cloth and heat curing. In addition, glass cloth used for continuously laminating uncured silicone rubber is generally subjected to sealing treatment to improve the strength and uncured silicone rubber material comes out on the opposite side of the glass cloth. To prevent that.

  A silicone resin is widely used as the sealing agent, but a method (dip coating) in which a large amount of a resin dissolved in an organic solvent such as toluene is prepared and the cloth is dipped and scraped off is often used. In addition, there is a lot of waste of silicone resin and organic solvent, and the equipment such as a vertical drying furnace is large and the cost efficiency is poor.

Japanese Patent No. 3902558 Japanese Patent No. 3244187 Japanese Patent No. 3029556 Japanese Patent No. 2938340 JP 2010-247413 A

  The present invention has been made in view of the above circumstances, and is a method for producing a glass cloth composite silicone rubber sheet having excellent releasability at low cost, which is mainly used in a thermocompression wiring connection process of electrical / electronic equipment components. The purpose is to provide.

  The above object of the present invention is to apply a silicone elastomer-forming composition that can be placed on a heat-cured silicone rubber sheet raw material by stacking a glass cloth and further cured by a hydrosilylation reaction on the glass cloth. It is achieved by a method for producing a glass cloth composite silicone rubber sheet, which is integrally molded by heat curing.

  That is, as a result of various investigations by the present inventors, a glass cloth that has not been subjected to a sealing treatment to fill the voids of the cloth is brought into contact with the heat-cured silicone rubber sheet raw material, A silicone elastomer-forming composition that can be cured by a hydrosilylation reaction, which is a liquid, is introduced and scraped while contacting the glass cloth with a knife or the like, so that the silicone elastomer-forming composition enters the glass cloth, and the glass cloth becomes silicone. It has been found that sufficient adhesion is also exhibited by sticking uniformly on a rubber sheet and further heat-curing.

  In addition, by this method, it is not necessary to perform a sealing treatment on the glass cloth in advance, and a silicone elastomer forming composition that can be cured by a hydrosilylation reaction is composed of a low-viscosity organopolysiloxane. Coating is also possible, greatly contributing to cost reduction.

  In addition, the use of low-viscosity organopolysiloxanes for solvent-free increases the cross-linking density, and can be expected to improve the releasability of anisotropic conductive adhesives using acrylic resins. Therefore, it is also possible to expect an improvement in releasability from an anisotropic conductive adhesive using an epoxy resin by reducing the inorganic powder (filler) in the composition (Patent Document 5: JP 2010-247413 A).

Therefore, this invention provides the manufacturing method of the following glass cloth composite silicone rubber sheet.
[1]
A glass cloth is placed on the heat-cured silicone rubber sheet, and a silicone elastomer-forming composition that can be cured by a hydrosilylation reaction is applied on the glass cloth. A method for producing a glass cloth composite silicone rubber sheet, comprising molding.
[2]
The silicone rubber sheet raw material has thermal conductivity containing a thermal conductive filler, and the silicone elastomer-forming composition is (A) an organopolysiloxane having two or more alkenyl groups in one molecule, ( [B] an organohydrogenpolysiloxane having hydrogen atoms directly bonded to two or more silicon atoms in one molecule, and (C) a platinum-based catalyst and a liquid composition at 25 ° C. Method.
[3]
The manufacturing method according to [1] or [2], wherein the glass cloth is pretreated with a vinyl group-containing silane coupling agent.
[4]
The manufacturing method according to any one of [1] to [3], wherein the glass cloth composite silicone rubber sheet is a thermocompression-bonding silicone rubber sheet for a thermocompression-bonding wiring connection process of electrical / electronic device parts.

By practicing the manufacturing method of the glass cloth composite silicone rubber sheet of the present invention, the manufacturing process can be simplified as compared with the conventional glass cloth composite silicone rubber sheet, and a significant cost reduction can be realized.
Moreover, compared with a single-layer thermally conductive silicone rubber sheet, the releasability of the anisotropic conductive film in the thermocompression wiring connection process of electrical / electronic equipment components can also be improved.

It is sectional drawing of the glass cloth composite silicone rubber sheet which concerns on one Example of this invention.

In the method for producing a glass cloth composite silicone rubber sheet of the present invention, as shown in FIG. 1, the glass cloth 12 is formed on the surface of a heat conductive silicone rubber sheet 13 that is heat-cured and molded on a release film 14 such as a polyester film. By applying a silicone elastomer-forming composition 11 that can be cured by a hydrosilylation reaction on the glass cloth, the heat conductive silicone rubber sheet 13 and the glass cloth 12 are brought into close contact with each other, and further heat-cured to form an integral molding. To do.
When this sheet is used in the thermocompression wiring connection process for electrical / electronic equipment parts, the polyester film is removed so that the heat conductive silicone rubber sheet is in contact with the pressure / heating metal tool and the glass cloth is in contact with the COF. It is to be used by arranging it.

The silicone elastomer-forming composition in the present invention is
(A) an organopolysiloxane having two or more alkenyl groups in one molecule;
(B) an organohydrogenpolysiloxane having hydrogen atoms directly bonded to two or more silicon atoms in one molecule;
It is preferable that (C) platinum-based catalyst: an effective amount, and if necessary, (D) reaction control agent: an effective amount.

  The component (A) is preferably a diorganopolysiloxane having at least two alkenyl groups, particularly vinyl groups, in one molecule, and is the main agent (base polymer) of the silicone elastomer-forming composition.

  The molecular structure of the alkenyl group-containing organopolysiloxane is not limited as long as it is liquid at room temperature (25 ° C.), and examples thereof include linear, branched, and partially branched linear, but are particularly preferable. Is linear. Examples of the alkenyl group include alkenyl groups having about 2 to 8 carbon atoms such as an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, and a cyclohexenyl group. Therefore, it is preferable to use a vinyl group.

  (A) As a group bonded to a silicon atom other than an alkenyl group in the component, in addition to a methyl group, as an unsubstituted or substituted monovalent hydrocarbon group, for example, an ethyl group, a propyl group, an isopropyl group, a butyl group, Cycloalkyl groups such as isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc., cyclopentyl group, cyclohexyl group, cycloheptyl group, etc. , Aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, biphenylyl group, aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group, methylbenzyl group, and carbon atoms of these groups Some or all of the hydrogen atoms are halogen atoms such as fluorine, chlorine, bromine, cyano groups, etc. Substituted groups such as chloromethyl, 2-bromoethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, fluorophenyl, cyanoethyl, 3,3,4,4 , 5, 5, 6, 6, 6-nonafluorohexyl group and the like having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, but cost, availability, chemical stability. All of them are preferably methyl groups for reasons such as environmental impact.

  The organopolysiloxane of component (A) can be used singly or in combination of two or more having different viscosities and compositions. In this case, it is preferable that the viscosity of the organopolysiloxane is 10 to 100,000 mPa · s, particularly 100 to 10,000 mPa · s at 25 ° C. measured by a rotational viscometer.

（式中、ｘ及びｙ、ｚは上記粘度値を与える数である。） In the present invention, as the organopolysiloxane, dimethylpolysiloxane having two or more vinyl groups is preferable, and in particular, those represented by the following general formula (1) are preferably used, but are represented by the following general formula (2). Thus, it may have a vinyl group in the side chain.

(In the formula, x, y, and z are numbers giving the above viscosity values.)

  Component (B) is an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms (that is, SiH groups) in the molecular chain side chain in one molecule, and acts as a crosslinking agent for component (A). It is an ingredient to do. That is, a hydrogen atom bonded to a silicon atom in the component (B) is added by a hydrosilylation reaction with an alkenyl group such as a vinyl group in the component (A) by the action of the platinum catalyst of the component (C) described later. Thus, a cross-linked cured product having a three-dimensional network structure having a cross-linked bond is obtained.

As the organic group bonded to the silicon atom in the component (B), an unsubstituted or substituted monovalent hydrocarbon group other than the alkenyl group can be used. To a methyl group.
The structure of the component (B) is not particularly limited and may be linear, branched or cyclic, but is preferably linear.

（式中、Ｒ¹はメチル基又は水素原子であり、分子鎖側鎖に少なくとも２個の水素原子が結合している。分子鎖末端にも水素原子が結合していてもよい。ｍは２以上の整数である。）
で表される。この場合、ＳｉＨ基は側鎖に存在しているものであり、側鎖のみにＳｉＨ基を有するものであってもよいが、側鎖に加えて分子鎖末端にもＳｉＨ基が存在してもよい。
また、ｍは好ましくは２〜２００、より好ましくは２０〜２００の整数である。ｍが小さすぎると塗工後硬化するまでに、揮発あるいは基材である熱伝導性ゴムシートへ浸透するジメチルポリシロキサン量が多くなり、安定した付加反応が得られなくなる。
なお、（Ｂ）成分は、１種単独でも２種以上を組み合わせても使用することができる。 Component (B) is, for example, the following general formula (3)

(In the formula, R ¹ is a methyl group or a hydrogen atom, and at least two hydrogen atoms are bonded to the side chain of the molecular chain. A hydrogen atom may be bonded to the terminal of the molecular chain. (It is an integer above.)
It is represented by In this case, the SiH group is present in the side chain and may have a SiH group only in the side chain. However, in addition to the side chain, the SiH group may be present at the end of the molecular chain. Good.
Moreover, m is preferably an integer of 2 to 200, more preferably 20 to 200. If m is too small, the amount of dimethylpolysiloxane that volatilizes or penetrates into the thermally conductive rubber sheet as the base material increases until it is cured after coating, and a stable addition reaction cannot be obtained.
In addition, (B) component can be used even if single 1 type also combines 2 or more types.

  The amount of the component (B) added is such that the SiH group of the component (B) is 0.5 to 5.0 moles with respect to 1 mole of the alkenyl group in the component (A), preferably 0.8 to 3. The amount is 0 mol. When the amount of SiH groups in component (B) is less than 0.5 moles per mole of alkenyl groups in component (A), the hardness of the cured product cannot be sufficiently obtained. On the other hand, if the amount exceeds 5.0 mol, a large amount of SiH groups remain, so that the releasability with respect to the anisotropic conductive adhesive is lowered.

  The platinum-based catalyst of the component (C) promotes the addition reaction between the vinyl group in the component (A) and the hydrogen atom bonded to the silicon atom in the component (B), and the three-dimensional network structure from the composition of the present invention. It is a component mix | blended in order to give the crosslinked hardened | cured material of.

(C) As a component, all the well-known catalysts used for normal hydrosilylation reaction can be used. Specific examples thereof include platinum group metals such as platinum (including platinum black), rhodium and palladium, H ₂ PtCl ₄ · nH ₂ O, H ₂ PtCl ₆ · nH ₂ O, NaHPtCl ₆ · nH ₂ O. , KHPtCl ₆ · nH ₂ O, Na ₂ PtCl ₆ · nH ₂ O, K ₂ PtCl ₄ · nH ₂ O, PtCl ₄ · nH ₂ O, PtCl ₂ , Na ₂ HPtCl ₄ · nH ₂ O (where, n is an integer of 0 to 6, preferably 0 or 6.), etc.), such as platinum chloride, chloroplatinic acid and chloroplatinate, alcohol-modified chloroplatinic acid, chloroplatinic acid and olefin complex, platinum black , Platinum group metals such as palladium supported on a carrier such as alumina, silica, carbon, rhodium-olefin complex, chlorotris (triphenylphosphine) rhodium (Wilkinso Catalyst), platinum chloride, chloroplatinic acid or chloroplatinate and a vinyl group-containing siloxane. In addition, the platinum-type catalyst of (C) component can be used even if single 1 type also combines 2 or more types.

  (C) The compounding quantity of a component should just be an effective amount required in order to harden a silicone composition, Although it does not restrict | limit, Usually, 0.1 mass in conversion of the mass of the platinum group metal element with respect to (A) component ˜1,000 ppm, preferably 0.5 to 500 ppm.

  The (D) component reaction control agent is an optional component for adjusting the reaction rate of the (A) component and the (B) component that proceed in the presence of the (C) component.

  As the component (D), all known addition reaction control agents used in ordinary addition reaction curable silicone compositions can be used. Specific examples thereof include acetylene compounds such as 1-ethynyl-1-cyclohexanol and 3-butyn-1-ol, nitrogen compounds, organic phosphorus compounds, sulfur compounds, oxime compounds, and organic chloro compounds. In addition, the reaction control agent of (D) component can be used even if single 1 type also combines 2 or more types.

  The blending amount of component (D) varies depending on the amount of component (C) used, and thus cannot be defined unconditionally. However, it may be any effective amount that can adjust the progress of the hydrosilylation reaction to a desired reaction rate. It is good to set it as about 10-50,000 ppm with respect to the mass of A) component. When the amount of component (D) is too small, sufficient pot life may not be ensured, and when too large, the curability of the composition may be lowered.

  Moreover, you may add a filler component in the silicone elastomer formation composition in this invention. Examples of the filler component include metals, metal oxides, metal nitrides, and metal carbides, among which reinforcing silica is particularly preferable.

  Silicone elastomers obtained by hydrosilylation reaction of organopolysiloxane are much weaker than other synthetic rubbers, and exhibit usable strength by adding a filler, particularly reinforcing silica, to organopolysiloxane.

Reinforcing silica is intended to be formulated in order to obtain a good silicone rubber in mechanical strength, BET method specific surface area of 50 m ² / g or more, particularly preferably 100 to 400 m ² / g. Examples of the reinforcing silica include fumed silica (dry silica), precipitated silica (wet silica), and the like, and fumed silica (dry silica) with few impurities is particularly preferable. Further, the surface of the reinforcing silica may be hydrophobized with organopolysiloxane, organosilazane, chlorosilane, alkoxysilane, or the like.

  The addition amount of the reinforcing silica is not particularly limited, but is preferably 0 to 30 parts by mass, particularly 5 to 20 parts by mass with respect to 100 parts by mass of the component (A). If excessively added to the organopolysiloxane, the viscosity of the coating solution of the silicone elastomer-forming composition is increased, so that uniform coating becomes difficult, so care must be taken.

By adjusting the viscosity of the organopolysiloxane, the addition amount of reinforcing silica, and optionally the addition amount of a diluting solvent, the viscosity of the coating solution is 100 to 20,000 mPa · s at 25 ° C. by a rotational viscometer. s, particularly 1,000 to 10,000 mPa · s is preferable. When the viscosity is lower than 100 mPa · s, the coating liquid spreads too much on the glass cloth, and the operability is poor. On the other hand, when the viscosity is higher than 20,000 mPsa, the coating thickness tends to be thick, the surface tack becomes strong, and the handleability of the composite sheet is deteriorated.
Compared to the solvent dilution coating, the solventless coating can increase the speed of the coating line and is not easily restricted by production facilities, so that productivity can be improved.

  If necessary, various alkoxysilanes such as adhesion aids, color pigments, heat resistance improvers, flame retardant improvers, acid acceptors, fluorine release agents, or reinforcing silica dispersants. Diphenylsilanediol, carbon functional silane, silanol group-containing siloxane, and the like may be added.

  As a coating method of the coating solution of the silicone elastomer forming composition of the present invention, there is a method of coating molding by a method such as knife coating, comma coating, bar coating, etc., solvent removal and heat curing as it is in the atmosphere, It is not limited to this. The heat curing is preferably performed at 120 to 180 ° C. for 3 to 10 minutes, but is not limited thereto.

  As the glass cloth used in the present invention, the average filament diameter of the yarn constituting the warp and weft is 4 μm or more and 8 μm or less, and the thickness is 0.03 mm or more and 0.20 mm or less, particularly 0.03 mm or more and 0.10 mm. Hereinafter, it is preferable that the density of the warp and the weft is 40/25 mm or more and 70/25 mm or less, respectively. If the filament diameter and thickness are smaller than this, the strength is insufficient, while if the filament diameter is larger, the thermal conductivity of the glass cloth composite silicone rubber sheet is significantly lowered. Moreover, even if the density of warp and weft is reduced, the strength is insufficient.

  Further, the glass cloth is preferably treated with a silane coupling agent so that the silicone elastomer-forming composition adheres strongly to the glass fiber. The types of silane coupling agents include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Epoxy group-containing silane coupling agents such as methoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, etc. Amino group-containing silane coupling agents, (meth) acrylic group-containing silane coupling agents such as 3-methacryloxypropyltrimethoxysilane, and the like, especially when a vinyl group-containing silane coupling agent is used. Improved adhesion of silicone resin .

  The heat conductive silicone rubber sheet raw material for laminating the glass cloth is a silicone rubber sheet having a thermal conductivity of 0.3 W / mK to 5 W / mK (ASTM E 1530), particularly 0.5 to 5 W / mK. It is preferable. Although it is affected by the thickness and thermal conductivity of the glass cloth layer, if the thermal conductivity is less than 0.3 W / mK, it is necessary to increase the thermocompression bonding temperature or to increase the crimping time. There are disadvantageous cases. If it exceeds 5 W / mK, the sheet hardness increases and uniform pressure bonding becomes difficult.

  Further, the thickness is preferably 0.1 mm or more and 1 mm or less. It is difficult to produce a product having a structure of less than 0.1 mm. Moreover, since thermal conductivity will fall when it exceeds 1 mm, it is necessary to raise the preset temperature of a crimping | compression-bonding machine, and since the mass per unit length becomes heavy, workability | operativity will also worsen.

  The composition constituting the heat conductive silicone rubber sheet raw material is selected from carbon, metal, metal oxide, metal nitride, metal carbide, etc. on 100 parts by mass of the same organopolysiloxane as the resin impregnated in the glass cloth. What is obtained by adding 10-1,600 mass parts of at least 1 sort (s) of a heat conductive filler is preferable. Specific examples of these include silver powder, copper powder, iron powder, nickel powder, aluminum powder, etc. for metal, zinc oxide, metal oxides such as magnesium, aluminum, silicon, iron, boron, aluminum for metal nitride, Examples of nitrides such as silicon and metal carbides include carbides such as silicon and boron.

  Various additives such as coloring pigments, heat resistance improvers, flame retardant improvers, acid acceptors, etc., as required, various alkoxysilanes, diphenylsilanediols, carbon functional silanes, silanol group-containing siloxanes, etc. May be added.

  The composition constituting the heat conductive silicone rubber sheet raw material is uniformly mixed using a kneading machine such as a two-roll, Banbury mixer, kneader, planetary mixer, etc. It can be obtained by heat treatment at a temperature.

  The curing agent that cures the heat conductive silicone rubber composition to form a rubber elastic body may be a conventionally known one that is usually used for curing silicone rubber, and this is a di-t- used for radical reaction. Organic peroxides such as butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and dicumyl peroxide, and organopolysiloxane as an addition reaction curing agent has two or more alkenyl groups In the case of having an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to a silicon atom in one molecule and a platinum-based catalyst, and when the organopolysiloxane contains a silanol group as a condensation reaction curing agent, Organosilicon having two or more hydrolyzable groups such as alkoxy group, acetoxy group, ketoxime group, propenoxy group Although such compounds may be mentioned, this amount may be the same as ordinary silicone rubber.

  As the composition constituting the heat conductive silicone rubber sheet raw material, either a millable type silicone rubber composition or a liquid type silicone rubber composition may be used. From the viewpoint of workability and moldability, an organic peroxide curable or addition reaction curable heat conductive silicone rubber composition is preferred.

  The hardness of the heat conductive silicone rubber sheet is preferably 30 or more and 90 or less (type A durometer defined in JIS K6253).

  The heat conductive silicone rubber sheet is formed by coating and baking continuously on a release film such as a polyester film, particularly a polyethylene terephthalate film (PET film) by a knife coating method, a comma coating method, a calendar coating method, or the like. . In particular, the calendar coating can be solvent-free coating, and the amount of organic solvent used can be reduced.

  In the manufacturing method of this invention, it is preferable to laminate | stack a glass cloth continuously in the state which attached the peeling film to the heat conductive silicone rubber sheet original fabric. Since the polyester film has higher strength and is less easily stretched compared to silicone rubber, it is suitable for stably and continuously laminating glass cloth.

  The method for producing a glass cloth composite silicone rubber sheet of the present invention is not limited to the thermocompression wiring connection process for electrical and electronic equipment parts, but is widely useful for producing a silicone rubber sheet reinforced with glass cloth.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1, Comparative Example 1]
(Composition of composition for heat conductive silicone rubber sheet raw fabric)
Methyl vinyl siloxane (having 0.03 mol at the terminal and 0.12 mol of vinyl group in the side chain with respect to 100 mol of dimethyl siloxane units, average polymerization degree is about 5,000), acetylene black (average particle size 35 nm, BET specific surface area of 130 m ² / g), hydrophobic silica (BET specific surface area of 120 m ² / g), cerium oxide (BET specific surface area of 140 m ² / g) are mixed in two rolls and kneaded. A rubber compound was obtained. The amount of each component was adjusted so that the finished hardness was 60 and the thermal conductivity was 0.5 W / mK.
The obtained compound is represented by 0.2 parts by mass of 1-ethynyl-1-cyclohexanol, 0.2 parts by mass of a chloroplatinic acid vinylsiloxane complex (platinum content: 0.5% by mass), and the following formula (4). 1.0 part by mass of organohydrogenpolysiloxane was sequentially added and kneaded uniformly.

(Conditions for forming the heat conductive silicone rubber sheet)
Next, using a calendering machine, the above composition was dispensed to a thickness of 0.25 mm and then transferred onto a PET film having a thickness of 0.1 mm. Subsequently, it was cured by passing through a heating furnace at 160 ° C. for 5 minutes.
Moreover, the single-layer rubber sheet for comparison was similarly molded so as to have a thickness of 0.45 mm. After peeling off the PET film, it was further heat treated at 400 ° C. for 4 hours. The reason why the comparative sheet is formed thick is to approximate the thermal conductivity to that of the glass cloth composite silicone rubber sheet as an example.

(Glass cloth)
A commercial product obtained by subjecting a plain woven glass cloth (thickness 0.06 mm, mass 48 g / m ² -JIS R 3414 EP06 equivalent) to vinylsilane treatment with vinyltrimethoxysilane was used.

(Silicone elastomer forming composition)
100 parts by mass of methyl vinyl siloxane-A (average polymerization degree is about 1,000 and has vinyl groups at both ends), 50 parts by mass of hydrophilic silica (BET specific surface area is 300 m ² / g), hexamethyldisilazane 10 After mixing part by mass and 2 parts by mass of tap water, a base rubber compound was obtained by heat treatment at 160 ° C. for 2 hours. To 100 parts by mass of this base rubber compound, 250 parts by mass of methylvinylsiloxane-B (average polymerization degree of about 300 and having vinyl groups at both ends), 1-ethynyl-1-cyclohexanol as a reaction control agent After adding 3 parts by mass and 0.5 parts by mass of a vinylsiloxane complex of chloroplatinic acid (platinum content: 0.5% by mass), 5 parts by mass of an organohydrogenpolysiloxane represented by the following formula (5) is added. The mixture was further kneaded to obtain a coating solution having a viscosity of about 5,000 mPa · s at 25 ° C. measured by a rotational viscometer.

(Coating method)
Overlay the glass cloth on the rubber surface side of the heat conductive silicone rubber sheet with PET film, apply the coating liquid from above, apply continuously to hold the glass cloth with a knife coater, 160 ℃ And cured for 5 minutes. Further, after the PET film was peeled off, heat treatment was performed at 400 ° C. for 4 hours to obtain a glass cloth composite silicone rubber sheet having a thickness of 0.33 mm.

(Pressure test evaluation for conductive film)
Fix the sheet under pressure and heated metal tool pressure heated to 350 ° C (with the glass cloth side facing down and stretch the sheet away from the tool and glass except during crimping), and further conductive under The glass substrate onto which the film has been transferred is inserted and pressure bonded at 5 MPa for 10 seconds. The glass substrate with the new conductive film transferred is inserted and pressure-bonded with the sheet as it is. While repeating this, the number of times until the sticking between the sheet and the conductive film became heavy was confirmed with an upper limit of 30 times.
The evaluation results are shown in Table 1.

In the step of laminating the heat conductive silicone rubber sheet raw material and the glass cloth, the raw material and the cloth were uniformly adhered after passing through the coater part, and strong adhesion was obtained after firing.
Also, in the pressure-bonding test with the conductive film, the heat-conductive silicone rubber single-layer sheet was broken by strong contact between the sheet and the conductive film in about 10 times, whereas the glass cloth composite silicone rubber sheet was 30 times. Good mold release properties were maintained even after pressure bonding. Moreover, neither peeling nor surface damage of the glass cloth was observed.

DESCRIPTION OF SYMBOLS 11 Silicone elastomer formation composition 12 Glass cloth 13 Heat conductive silicone rubber sheet original fabric 14 Release film

Claims (4)

  A glass cloth is placed on the heat-cured silicone rubber sheet, and a silicone elastomer-forming composition that can be cured by a hydrosilylation reaction is applied on the glass cloth. A method for producing a glass cloth composite silicone rubber sheet, comprising molding.   The silicone rubber sheet raw material has thermal conductivity containing a thermal conductive filler, and the silicone elastomer-forming composition is (A) an organopolysiloxane having two or more alkenyl groups in one molecule, ( 2. The process according to claim 1, wherein the composition is a liquid composition at 25 ° C. containing B) an organohydrogenpolysiloxane having hydrogen atoms directly bonded to two or more silicon atoms in one molecule and (C) a platinum-based catalyst. Method.   The manufacturing method according to claim 1 or 2, wherein the glass cloth is surface-treated with a vinyl group-containing silane coupling agent in advance.   The manufacturing method according to any one of claims 1 to 3, wherein the glass cloth composite silicone rubber sheet is a silicone rubber sheet for thermocompression bonding for a thermocompression wiring connection process of electrical / electronic equipment parts.

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