JP2008305817A - Cushion sheet for manufacturing fpc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cushion sheet for manufacturing a FPC equipped with a silicone rubber layer which has improved thermal conductivity to be used in a quick press compression-bonding and is pasted on at least one of surfaces of a metallic plate. <P>SOLUTION: The cushion sheet to be used in the quick press compression-bonding and pasting step during a manufacturing process of the FPC (flexible printed circuit) is equipped with the thermally conductive silicone rubber layer with a thermal conductivity of 0.4 W/mK or higher on at least one of surfaces of the metallic plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cushion sheet used in a quick press pressure bonding process in an FPC (flexible printed circuit board) manufacturing process.

  FPC (Flexible Printed Circuits): During the manufacturing process of a flexible printed circuit board, there is a process of bonding a cover lay film or a reinforcing plate. In this step, the member is attached with a thermosetting epoxy adhesive or the like, and heating under uniform pressure is required. Currently, there are two typical methods for the pressure bonding process in this heating press. One is a quick press system, in which a press molding machine with cushion sheets attached to the top and bottom of the press plate is always heated to a predetermined temperature, and the FPC is placed on the press molding machine on one side and bonded by pressure bonding. It is a method to do. The other is a multi-stage press method in which a plurality of FPCs are stacked and set on a press molding machine near room temperature via a cushion sheet, and after pressurization and temperature rise, cooling and pressure bonding are performed. At present, the quick press method has become mainstream because of its good productivity and fine adjustment.

  In either method, the cushion sheet is used when the FPCs are bonded together, and the effect of maintaining the adhesive in a uniform thickness and the deformation of the product due to the unevenness of the FPC pattern and the flow of the adhesive during pressurization. It is an extremely important part that has the effect of preventing wire breakage.

  As a recent trend, the demand for a so-called multilayer FPC in which a plurality of substrates are stacked for the purpose of being small and highly integrated is increasing. In this multi-layer FPC, heat transfer is difficult in the pressure bonding process, so conventional cushion sheets made of rubber materials do not have sufficient thermal conductivity and can be made with longer molding cycles or higher set temperatures and pressures. is doing. When the molding cycle is lengthened, the productivity is naturally deteriorated. When the temperature and pressure are set high, deformation of the FPC is likely to occur and the yield decreases, and thermal deterioration of the cushion sheet itself is promoted, and the life of the cushion sheet is shortened.

  In this bonding step, since the curing temperature of the adhesive is as high as 100 ° C. or higher, the temperature of the cushion sheet may rise to nearly 200 ° C. in consideration of the thermal resistance of each member. Therefore, since heat resistance is required for the cushion sheet, at present, silicone rubber and fluororubber are mainly used.

  Generally, although fluororubber is excellent in heat resistance, it is difficult to produce a soft rubber hardness, and only a relatively hard one can be prepared. Therefore, sufficient cushioning properties may not be obtained. In addition, fluororubber has very poor wettability to various fillers, so that it is difficult to fill other than the limited carbon black and it is difficult to impart thermal conductivity. Further, in the case of fluororubber, it is also a problem that in the FPC bonding step, the release from the protective film used between the cushion sheet and the FPC is poor.

  In addition, although the pressure bonding method which does not use an elastic body is also examined, it is difficult to stabilize the quality and is not practically used at present.

In addition, although there exist the following as a well-known literature relevant to this invention, all were not sufficient in heat conductivity.
Japanese Patent Laid-Open No. 2-310990 JP-A-4-201441 Japanese Patent Laid-Open No. 4-201442 JP-A-4-201443 JP-A-4-350992 JP-A-4-351546 JP 2003-170300 A JP 2003-170458 A JP 2002-368387 A JP 2002-335064 A JP 2002-144484 A JP 2007-098816 A Japanese Patent Laid-Open No. 2005-002148

  The present invention has been made in view of the above circumstances, and provides a cushion sheet for FPC manufacturing in which a silicone rubber layer having an increased thermal conductivity used in a quick press pressure bonding process is provided on at least one surface of a metal plate. With the goal.

  As a result of intensive studies on a method for shortening the molding cycle and improving the productivity in the quick press method, the present inventors have found that the material of the silicone rubber layer conventionally used as a cushioning material has a thermal conductivity of 0. It has been found that good results can be obtained by using a silicone rubber layer having a thermal conductivity of 4 W / mK or more, and has led to the present invention.

  Therefore, the present invention is a cushion sheet used in the quick press pressure bonding process in the FPC manufacturing process, and a thermally conductive silicone rubber layer having a thermal conductivity of 0.4 W / mK or more is at least on one side of the metal plate. Provided is a cushion sheet for manufacturing an FPC.

  The cushion sheet for FPC production of the present invention has excellent thermal conductivity and good cushioning properties, so that heat transfer from the press molding machine to the FPC is good. Therefore, the molding cycle can be shortened and productivity can be improved. In addition, since the set temperature can be lowered, the cost can be reduced by reducing the electric power and extending the life by reducing the thermal deterioration of the cushion sheet itself.

  The cushion sheet for FPC production of the present invention is a cushion sheet used in a quick press pressure bonding process in the FPC production process, and a thermally conductive silicone rubber layer having a thermal conductivity of 0.4 W / mK or more is at least a metal. It is provided on one side of the plate.

  The heat conductive silicone rubber used in the cushion sheet for FPC production of the present invention is not particularly limited as long as the heat conductivity is 0.4 W / mK or more, preferably 0.6 to 5.0 W / mK. Absent. In the present invention, the thermal conductivity is measured by the ASTM E 1530 protective heat flow meter method.

As such a heat conductive silicone rubber, (A) 100 parts by mass of an organopolysiloxane having an average degree of polymerization of 100 or more, (B) 0 to 100 parts by mass of carbon black, and (C) a BET specific surface area of 50 m ² / g. 0 to 1,600 parts by mass of fine powdered silica as described above, (D) metal, metal oxide other than component (C), metal nitride, and metal carbide. It is preferable that it is a hardened | cured material of the silicone rubber composition formed by containing a mass part and (E) hardening | curing agent. Moreover, in order to ensure the thermal conductivity of 0.4 W / mK or more, it is necessary that the total of the component (B), the component (C), and the component (D) is 50 to 1,600 parts by mass.

The organopolysiloxane having an average degree of polymerization of 100 or more as the component (A) is preferably represented by the following average composition formula.
R ¹ _a SiO _{(4-a) / 2}
(In the formula, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and a is a positive number of 1.95 to 2.05.)

Here, R ¹ in the above formula represents a substituted or unsubstituted monovalent hydrocarbon group. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, vinyl group, allyl group, propenyl group, butenyl group and hexenyl group. An aryl group such as alkenyl group, phenyl group, tolyl group and xylyl group, aralkyl group such as benzyl group and 2-phenylethyl group, or part or all of hydrogen atoms bonded to carbon atoms of these groups. , A chloromethyl group substituted with a halogen atom, a cyano group, or the like, a trifluoropropyl group, a cyanoethyl group, or the like, the same or different, unsubstituted or substituted one having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms And valent hydrocarbon groups. In the present invention, when the component (A) is oily, it preferably contains at least two alkenyl groups in one molecule. In the case of raw rubber, 0.001 to 5 mol%, particularly 0.01 to 1 mol% of R ¹ is preferably an alkenyl group.

  The average degree of polymerization of the organopolysiloxane is 100 or more, preferably 150 to 20,000, more preferably 3,000 to 20,000. If the degree of polymerization is less than 100, the mechanical strength after curing may be inferior and brittle. If the degree of polymerization is greater than 20,000, the processability may deteriorate. In addition, an average degree of polymerization is a value calculated | required by converting using the analytical curve created with the polystyrene standard sample by GPC (gel permeation chromatography) measurement data.

  The component (B), carbon black, not only improves the heat resistance and thermal conductivity of the silicone rubber layer, but also improves mechanical strength and imparts antistatic properties by making the silicone rubber sheet conductive. .

  In general, since the heat resistance of silicone rubber is affected by the pH, moisture or impurities in the composition, it is necessary to pay close attention to the selection of additives. Although carbon black can improve the heat resistance of silicone rubber, it is necessary to consider its impurities and volatile components. The volatile content of carbon black corresponds to the mass of oxygen compounds (acidic components such as carboxyl, quinone, lactone, hydroxyl, etc.) that are chemically adsorbed on the surface, but this oxygen compound is vaporized from the surface by heating. Therefore, it adversely affects the heat resistance of the silicone rubber. Accordingly, it is preferable to use a material having a low volatile content. Specifically, a carbon black having a volatile content other than water of 1.0% by mass or less and further a volatile content of 0.5% by mass or less is used. Is preferred.

  Here, as a method for measuring volatile matter in the present invention, the method described in “Testing method of carbon black for rubber” of JIS K 6221 is used. Specifically, a specified amount of carbon black is put into a crucible, and the volatilization loss after heating at 950 ° C. for 7 minutes is measured.

  Carbon black is classified into furnace black, channel black, thermal black, acetylene black, etc. according to the manufacturing method. In the present invention, any of these carbon blacks may be used. As the carbon black having a volatile content of 1.0% by mass or less, acetylene black, conductive carbon black and the like are suitable (for example, Japanese Patent Laid-Open No. Hei 1). No. 272667, page 3, lines 36-40).

A carbon black having a large specific surface area has a greater effect of improving heat resistance and suppressing a decrease in mechanical strength at high temperatures. Therefore, in the present invention, a carbon black having a BET specific surface area of 30 m ² / g or more is preferable. It is preferably 50 m ² / g or more, and more preferably 100 m ² / g or more. The upper limit of the BET specific surface area is preferably 1,000 m ² / g or less, particularly preferably 500 m ² / g or less.

  The blending amount of the component (B) is preferably 0 to 100 parts by mass, more preferably 0 to 70 parts by mass, and 0 to 50 parts by mass with respect to 100 parts by mass of the component (A). Is more preferable. If the amount is more than 100 parts by mass, the plasticity of the silicone rubber composition may be too high, resulting in poor moldability, or the cured rubber may be too hard. In addition, when mix | blending, it is preferable to mix | blend 1 mass part or more with respect to 100 mass parts of (A) component.

(C) The fine powder silica whose BET specific surface area of a component is 50 m < ² > / g or more is used as a reinforcement component of silicone rubber. The finely divided silica may be of even hydrophobic ones hydrophilic, but preferably from the viewpoint of reinforcing the BET specific surface area of 50 to 800 m ² / g, especially of 100 to 500 m ² / g Is good. When the specific surface area is less than 50 m ² / g, the reinforcing effect cannot be obtained sufficiently.

  The compounding amount of the component (C) is preferably 0 to 100 parts by mass, more preferably 0 to 70 parts by mass, and 0 to 50 parts by mass with respect to 100 parts by mass of the component (A). Is more preferable. If the amount is more than 100 parts by mass, the plasticity of the silicone rubber composition may be too high, resulting in poor moldability, or the cured rubber may be too hard. In addition, when mix | blending, it is preferable to mix | blend 1 mass part or more with respect to 100 mass parts of (A) component.

  The component (D) is at least one heat conductive powder selected from metals, metal oxides other than the component (C), metal nitrides, and metal carbides, and provides thermal conductivity to the silicone rubber sheet of the present invention. It is given. Examples of these include silver, copper, iron, metallic silicon, nickel, aluminum, etc. for metals, zinc oxide, aluminum oxide, magnesium oxide, silicon dioxide, iron oxide, etc. for metal oxides, boron nitride for metal nitrides, Examples of metal carbides such as aluminum nitride and silicon nitride include silicon carbide and boron carbide.

The average particle size of the heat conductive powder is not particularly limited, but is preferably 0.1 to 100 μm, and more preferably 0.5 to 50 μm. When the average particle size is less than 0.1 μm, the specific surface area of the powder becomes relatively large, so that high filling becomes difficult, the thermal conductivity becomes insufficient, and the cured rubber may become too hard. When the average particle size is larger than 100 μm, the cured rubber becomes brittle and unevenness is easily formed on the surface, which is not preferable. In the present invention, the average particle diameter is a volume-based cumulative average diameter by laser diffraction. Specifically, it can be measured by, for example, Microtrack, which is a particle size analyzer manufactured by Nikkiso Co., Ltd.
The particle shape of the heat conductive powder includes a spherical shape, an elliptical shape, a flat shape, an angular irregular shape, a rounded irregular shape, and a needle shape, but is not particularly limited in the present invention.

  (D) It is preferable that the compounding quantity of a component is 0-1,600 mass parts with respect to 100 mass parts of (A) component, and it is preferable to use in the range of 0-1,000 mass parts especially. When the amount is more than 1,600 parts by mass, blending becomes difficult and molding processability deteriorates. In addition, when mix | blending, it is preferable to mix | blend 10 mass parts or more with respect to 100 mass parts of (A) component.

  Moreover, it is preferable that the total compounding quantity of (B) component in this invention, (C) component, and (D) component is 50-1,600 mass parts with respect to 100 mass parts of (A) component, 100- The amount is more preferably 1,200 parts by mass, and still more preferably 120 to 800 parts by mass. If the total blending amount of the component (B), the component (C) and the component (D) is too small, the thermal conductivity may not be sufficient. If the blending amount is too large, the blending becomes difficult and the processability may be deteriorated. is there.

  The curing agent of component (E) can be appropriately selected from known curing agents that are usually used for curing silicone rubber. Examples of these curing agents include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide and the like used for radical reactions. When the organic peroxide or the organopolysiloxane of component (A) has two or more alkenyl groups, it contains two or more hydrogen atoms bonded to silicon atoms in one molecule as an addition reaction curing agent. For those composed of organohydrogenpolysiloxane and platinum-based catalyst, or when the organopolysiloxane of component (A) contains two or more silanol groups, alkoxy group, acetoxy group, ketoxime as condensation reaction curing agent And organosilicon compounds having two or more hydrolyzable groups such as a group and a propenoxy group. In the present invention, it is preferable to cure by radical reaction and / or addition reaction.

  The addition amount of these curing agents may be the same as in the case of ordinary silicone rubber. For example, in the case of radical reaction, the organic peroxide is added in an amount of 0.1 to 10 parts per 100 parts by mass of component (A). In an amount of mass part, in the case of addition reaction, the amount that the SiH group of the organohydrogenpolysiloxane is 0.5 to 5 moles relative to the alkenyl group of the component (A) and the amount that the platinum-based catalyst is 1 to 1,000 ppm It is preferable to use it. In addition, organic peroxide, organohydrogenpolysiloxane, and platinum-based catalyst can be added at the same time and cured by two reactions of radical reaction and addition reaction. It is preferable to add according to the above.

In the present invention, although optional, the heat resistance can be improved by adding cerium oxide powder (component (F)) to the silicone rubber composition as necessary. The addition amount of the cerium oxide is in the range of 0.1 to 5 parts by mass, preferably 0.2 to 2 parts by mass with respect to 100 parts by mass of the component (A). On the contrary, when the addition amount exceeds 5 parts by mass, the heat resistance may decrease. As the cerium oxide powder, it is preferable to use a powder having a relatively large specific surface area of BET specific surface area of 50 m ² / g or more.

  In the silicone rubber composition, a filler such as clay, calcium carbonate, diatomaceous earth, titanium dioxide, a dispersant such as low molecular siloxane ester, silanol, silane, etc., as long as the object of the present invention is not impaired. As other components, adhesion imparting agents such as coupling agents and titanium coupling agents, platinum group metal catalysts for imparting flame retardancy, tetrafluoropolyethylene particles for increasing the green strength of rubber compounds, and the like may be added.

The silicone rubber composition may be prepared by kneading the above components using a mixer such as a planetary mixer, a kneader, a two-roll, a three-roll, or a Banbury mixer, but a curing agent is used. It is preferable to add it immediately before.
Here, the curing conditions for curing the silicone rubber composition are appropriately selected. The heat curing conditions are 60 to 200 ° C., particularly 80 to 180 ° C. for 1 to 60 minutes, particularly 5 to 5 minutes. Preferably it is 30 minutes.

  The metal plate of the cushion sheet for FPC production of the present invention is preferably iron, stainless steel, aluminum, copper, or an alloy thereof in terms of thermal conductivity, cost, and availability.

The thickness of the metal plate of the cushion sheet for FPC production is preferably 0.02 to 10 mm. If the thickness is less than 0.02 mm, handling during manufacture of the cushion sheet for FPC manufacture becomes difficult, and the reinforcing effect of the completed cushion sheet for FPC manufacture may not be sufficient. If it is thicker than 10 mm, the mass may be too heavy and handling may be worse.
The thickness of the heat conductive silicone rubber is preferably 0.05 to 10 mm, particularly 0.1 to 10 mm. If it is thinner than 0.05 mm, the cushion effect is insufficient, and there is a possibility that uniform pressure bonding cannot be performed. If it is thicker than 10 mm, heat transfer may not be sufficient.

  Although the following methods can be considered as a manufacturing method of the cushion sheet for FPC manufacture of this invention, it is not limited to these.

  As a method of laminating and molding the silicone rubber composition obtained above with a metal plate, the silicone rubber composition containing up to a curing agent is dispensed to a predetermined thickness with a calendar molding machine or an extruder and then the metal plate. And a method of curing by applying a liquid silicone rubber composition or a silicone rubber composition liquefied by dissolving in a solvent such as toluene on a metal plate. In order to further strengthen the adhesion between the thermally conductive silicone rubber layer and the metal plate, the metal plate surface may be subjected to a primer treatment as necessary.

The cushion sheet for FPC production of the present invention has a thermally conductive silicone rubber layer provided on at least one side of a metal plate, and the thermally conductive silicone rubber layer may be provided only on one side of the metal plate. You may provide a heat conductive silicone rubber layer on both surfaces of a board. When providing a heat conductive silicone rubber layer on both surfaces of a metal plate, those materials may be the same or different. Moreover, the thickness of each of the heat conductive silicone rubber layers may be the same or different. However, when silicone rubber layers are provided on both sides of the metal plate, the silicone rubber layer on the surface that contacts the press machine is mainly intended to reduce the contact thermal resistance between the press plate of the press machine and the cushion sheet for FPC manufacturing. Therefore, the thinner one is desirable. Specifically, the thickness is desirably 0.05 to 0.5 mm. On the other hand, the silicone rubber layer facing the FPC is required to have a certain thickness because it is required to have cushioning properties as well as heat conduction. Specifically, the thickness is desirably 0.1 to 10 mm.

  By using the cushion sheet for manufacturing the FPC of the present invention thus obtained, heat transfer from the press molding machine to the FPC is improved, so that the molding cycle can be shortened and the productivity can be improved. . In addition, since the set temperature can be lowered, the cost can be reduced by reducing power consumption and extending the life of the cushion sheet itself.

  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. In the following examples, the average particle size of the carbon black component (B) is a method of taking a photograph with an electron microscope and measuring the primary particle diameter with the photograph, an arithmetic operation of the particle diameter obtained by so-called electron microscopy. Say the average value. Carbon black usually exists in the form of aggregated particles in which primary particles are aggregated, but the average particle size referred to here is not the average particle size of aggregated particles but the average particle size of primary particles. The average particle diameter of the thermally conductive powder of component (D) is a volume-based cumulative average diameter by laser diffraction.

[Examples 1 to 5, Comparative Examples 1 and 2]
(Manufacture of cushion sheets for evaluation)

<< Preparation of thermally conductive silicone rubber composition >>
The following raw materials were prepared.
・ Organopolysiloxane:
(A-1) Methyl vinyl polysiloxane having 99.85 mol% of dimethyl siloxane units and 0.15 mol% of methyl vinyl siloxane units and having an average degree of polymerization of 8,000 and both ends of the molecular chain blocked with dimethyl vinyl siloxy groups (A-2) Methyl vinyl polysiloxane having an average degree of polymerization of 8,000 consisting of 99.5 mol% of dimethyl siloxane units and 0.5 mol% of methyl vinyl siloxane units and having both molecular chain ends blocked with dimethyl vinyl siloxy groups (A-3) dimethylpolysiloxane having an average degree of polymerization of 750 and having both molecular chain ends blocked with dimethylvinylsiloxy groups (a-4) average polymerization consisting of 95 mol% of dimethylsiloxane units and 5 mol% of methylvinylsiloxane units Methylvinylpolysiloxane having both molecular chain ends blocked with trimethylsiloxy groups at a degree of 200 Sun

·Carbon black:
(B-1) Acetylene black / fine powder silica having an average particle size of 35 nm, a volatile content other than water of 0.10% by mass, and a BET specific surface area of 69 m ² / g:
(C-1) Hydrophobic silica having a BET specific surface area of 110 m ² / g (trade name: Aerosil R-972, manufactured by Degussa Corporation)
・ Thermal conductive powder:
(D-1) crystalline silicon dioxide powder having an average particle diameter of 4 μm (d-2) metal silicon powder having an average particle diameter of 11 μm (d-3) aluminum powder having an average particle diameter of 2.5 μm

・ Curing agent:
(E-1) 2,5-dimethyl-2,5-di (t-butylperoxy) hexane: 50% by mass, 99.85 mol% of dimethylsiloxane units, 0.15 mol% of methylvinylsiloxane units Methylvinylpolysiloxane having an average degree of polymerization of 8,000 and having both molecular chain ends blocked with dimethylvinylsiloxy groups: 50% by mass paste (e-2) Vinylsiloxane complex of chloroplatinic acid (platinum content 1% by mass) )
(E-3) The following formula (1):
Methyl hydrogen polysiloxane (e-4) represented by the following formula (2):
Methyl hydrogen polysiloxane represented by

・ Other ingredients:
(F-1) Cerium oxide powder having a BET specific surface area of 140 m ² / g (f-2) 50% by mass toluene solution of ethynylcyclohexanol

The base compound of the heat conductive silicone rubber layer was produced by the following method.
Base compound 1:
The raw materials shown in Table 1 were kneaded uniformly without heating using a pressure kneader to obtain a base compound 1.
Base compounds 2-4:
The raw materials shown in Table 1 were uniformly kneaded using a pressure kneader, further heat-mixed at 150 ° C. for 2 hours, and then cooled to obtain base compounds 2 to 4.
Base compound 5:
The base compound 5 was obtained by uniformly mixing the raw materials shown in Table 1 at room temperature using a planetary mixer.

Using the base compound, rubber compositions 1 to 5 were produced by the following method.
Rubber compositions 1 to 4:
To 100 parts by mass of the base compound obtained above, the curing agents e-1 to 3 shown in Table 2 below, f-1: cerium oxide powder and f-2: control agent are uniformly kneaded with two rolls. Thus, rubber compositions 1 to 4 which are curable thermally conductive silicone rubber compositions were obtained.
Rubber composition 5:
To the 100 parts by mass of the base compound obtained above, the curing agents e-2 and 4 shown in Table 2 below, f-1: cerium oxide powder and f-2: control agent are uniformly kneaded with a planetary mixer. Thus, a rubber composition 5 which is a curable thermally conductive silicone rubber composition was obtained.

<Measurement of various physical properties of thermally conductive silicone rubber>
Using the obtained rubber composition, physical properties and thermal conductivity were measured by the following methods. Table 2 shows the composition of the rubber composition and the measurement results of the physical properties.

[Hardness (durometer type A), elongation at break, tensile strength]
The rubber composition was heat press molded at 150 ° C. for 10 minutes to produce a 2 mm thick sheet. Further, the sheet was heat-treated at 200 ° C. for 4 hours and measured according to JIS K 6249.

[Thermal conductivity]
The rubber composition was subjected to hot press molding at 150 ° C. for 10 minutes to produce a disk having a diameter of 50 mm and a thickness of 9 mm. Further, the disk was heat-treated at 200 ° C. for 4 hours, and measured according to ASTM E 1530.

<< FPC cushion sheet production >>
In the following steps, FPC cushion sheets of Examples 1 to 4 and Comparative Examples 1 and 2 of the present invention were produced. Each configuration is shown in Tables 3 and 4.
(1) Preparation of 500 × 500 mm metal plate (2) Surface degreasing with acetone (3) Primer coating (4) The rubber compositions 1 to 3 are calendered to a predetermined thickness on a PET film In some cases, both sides are molded)
(5) Bonding to a metal plate (In the case of a double-sided silicone layer, bonding to both sides)
(6) Heat press molding: 150 ° C., 30 minutes (7) PET film is peeled off and heat treatment: 200 ° C., 4 hours

The FPC cushion sheet of Example 5 of the present invention was produced through the following steps. Each configuration is shown in Table 4.
(1) Preparation of 500 × 500 mm metal plate (2) Surface degreasing with acetone (3) Primer application (4) Silicone layer 1 is applied on metal plate to a predetermined thickness with a bar coater (5) HAV vulcanization as it is: 150 ° C., 30 minutes (6) Primer application on the other side of the metal plate (7) The rubber composition 5 is applied to the metal plate with a bar coater to a predetermined thickness. (8) HAV vulcanization: 150 ° C, 30 minutes (9) Heat treatment: 200 ° C, 4 hours

<< Evaluation of FPC cushion sheet >>
Set the FPC cushion sheet of Example 1 or Comparative Example 1 on the upper plate surface of the press molding machine having a 500 × 500 mm press plate surface so that the silicone layer 1 faces the surface opposite to the plate surface of the press molding machine. Then, the FPC cushion sheets of Examples 2 to 5 or Comparative Example 2 were set on the lower plate surface of the press molding machine, and the thermal conductivity was evaluated by the method described below.

[Evaluation of thermal conductivity]
A temperature when a thermocouple of φ50 μm is set at the center of the surface of the silicone layer 1 of the FPC cushion sheet set on the lower press plate, and the press molding machine is set to 200 ° C. and pressed at a pressure of 1 MPa for 240 seconds. The rise was measured. The results are shown in the graph of FIG.

  By using the FPC cushion sheet in which the silicone rubber layer having a thermal conductivity of 0.4 W / mK or more, which is an example of the present invention, is used, the conventionally used silicone having a low thermal conductivity shown in the comparative example. It can be seen that the rate of temperature increase is much faster than the FPC cushion sheet with the rubber layer disposed, and the maximum temperature reached is high.

It is a graph which shows the heat conduction evaluation result of the FPC cushion sheet in the Example of this invention.

Claims (6)

  A cushion sheet used in a quick press pressure bonding process in the FPC (flexible printed circuit board) manufacturing process, and a thermal conductive silicone rubber layer having a thermal conductivity of 0.4 W / mK or more is provided on at least one surface of a metal plate. A cushion sheet for manufacturing FPC. The thermally conductive silicone rubber is (A) 100 parts by mass of an organopolysiloxane having an average degree of polymerization of 100 or more, (B) 0 to 100 parts by mass of carbon black, and (C) a BET specific surface area of 50 m ² / g or more. 0 to 1,600 parts by mass of powder silica (0) to 1,600 parts by mass of (D) metal, metal oxide other than component (C), metal nitride and metal carbide , (B) component, (C) component, and (D) component is 50 to 1,600 parts by mass), and (E) a cured product of a thermally conductive silicone rubber composition containing a curing agent. The cushion sheet for FPC manufacture of Claim 1.   Component (D) is selected from silver, copper, iron, metallic silicon, nickel, aluminum, zinc oxide, aluminum oxide, magnesium oxide, silicon dioxide, iron oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, and boron carbide. The cushion sheet for FPC manufacture according to claim 2, wherein the cushion sheet is at least one kind.   The cushion sheet for FPC manufacture according to claim 2 or 3, wherein the thermally conductive silicone rubber composition further contains 0.1 to 5 parts by mass of (F) cerium oxide powder with respect to 100 parts by mass of the component (A). .   The cushion sheet for FPC manufacture of any one of Claims 1-4 in which a metal plate consists of iron, stainless steel, aluminum, copper, or those alloys.   The cushion sheet for FPC manufacture according to any one of claims 1 to 5, wherein the thickness of the metal plate is 0.02 to 10 mm, and the thickness of the thermally conductive silicone rubber layer is 0.05 to 10 mm.