Silicone adhesive packing material for printed circuit boards and method of use

Abstract

Provided are a silicone adhesive packing material for printed circuit boards, which can eliminate the risk of the printed circuit board being damaged by ions or the like, leading to circuit malfunction, and can prevent restrictions on the wiring and electrical connections of the printed circuit board, and a method for using the same. [Solution] A printed circuit board 1, which has multiple electronic components 3 mounted and is to be built into the e-axle of an electric vehicle, is encapsulated by sandwiching the entire board between a pair of upper and lower silicone adhesive packing materials 10 for printed circuit boards, and the peripheral edges 12 of the pair of silicone adhesive packing materials 10 for printed circuit boards are seam-jointed and pressure-welded to each other. Because the printed circuit board 1 is encapsulated, corrosion of the printed circuit board 1 by ions such as chloride ions can be prevented. Furthermore, because the silicone adhesive packing material 10 for printed circuit boards is flexible before curing, there are no restrictions on the wiring or electrical connections of the printed circuit board 1.

Description

[Technical Field]

[0001] The present invention relates to a silicone adhesive packing material for printed circuit boards used in transportation means, medical equipment, music equipment, home appliances, industrial equipment, information equipment, precision equipment, electrical equipment, electronic equipment, etc., and to a method for using the same. [Background technology]

[0002] A printed circuit board is a printed circuit assembly in which multiple electronic components are electrically connected to a printed circuit board (see Patent Documents 1, 2, 3, and 4), and is used in transportation, medical equipment, music equipment, home appliances, industrial equipment, information equipment, precision equipment, electrical equipment, electronic equipment, etc., but is also widely used in automobiles.

[0003] For example, modern automobiles are equipped with various ECUs (electronic control units) that control various functions to improve the safety, comfort, and environmental friendliness of the automobile, and printed circuit boards in these ECUs are manually housed in dedicated resin cases (see Patent Document 5). Furthermore, in recent years, electric vehicles (EVs) 20 that do not require fossil fuels have been attracting attention, and as shown in Fig. 4, these electric vehicles 20 are equipped with e-axles (eAxles: EV drive modules) 21 that contribute to size and weight reduction, space saving, improved power consumption, and cost reduction. The printed circuit boards for the inverters are manually housed in housing 22 of these e-axles 21 either directly or via dedicated resin cases. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2024-060964 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-092103 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-225393 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-209566 [Patent Document 5] Japanese Patent Application Publication No. 2019-089514 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional printed circuit boards are used as described above, but when handled manually, simply housed in a resin case lacking airtightness, or used in a high-temperature, high-humidity environment, they can be corroded by ions such as chloride ions, resulting in circuit malfunction. Furthermore, when the resin case is a specialized product, the fixed shape of the resin case can impose restrictions on the wiring and electrical connections of the printed circuit board. Furthermore, when a heavy resin case is used in an electric vehicle 20, this heavy resin case can hinder efforts to improve the electric vehicle's 20 fuel economy.

[0006] The present invention has been made in view of the above, and its object is to provide a silicone adhesive packing material for printed circuit boards that eliminates the risk of printed circuit board damage caused by ions, etc., leading to circuit malfunction, and prevents restrictions on the wiring and electrical connections of the printed circuit board, as well as a method for using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention is characterized in that a printed circuit board on which electronic components are mounted is encapsulated with a silicone adhesive packing material for printed circuit boards.

[0008] The printed circuit board may be built into at least one of the vehicle's ECU and e-axle. In addition, the silicone adhesive packing material for printed circuit boards may be formed into a rubber sheet using a moisture condensation curing silicone rubber composition, an addition curing silicone rubber composition or a combination thereof, a UV curing silicone rubber composition, a radical polymerization silicone rubber composition, a radical condensation polymerization silicone rubber composition, a polyimide-modified silicone rubber composition, or an epoxy-modified silicone rubber composition.

[0009] The silicone adhesive packing material for printed circuit boards is preferably molded into a light-transmitting rubber sheet. It is also preferable that the silicone adhesive packing material for printed circuit boards be able to form a gap between it and some of the taller electronic components on the printed circuit board by coming into contact with them.

[0010] In order to solve the above problems, the present invention also provides a method for using the silicone adhesive packing material for printed circuit boards as set forth in claim 1 or 2, which comprises the steps of: The printed circuit board is sandwiched between a pair of silicone adhesive packing materials for printed circuit boards, and the peripheral edges of the pair of silicone adhesive packing materials for printed circuit boards are pressed together to bond them together. The pair of silicone adhesive packing materials for printed circuit boards can be seamed and pressure welded together at their peripheral edges.

[0011] In order to solve the above problems, the present invention also provides a method for using the silicone adhesive packing material for printed circuit boards as set forth in claim 1 or 2, which comprises the steps of: The printed circuit board is fitted into a substantially tubular silicone adhesive packing material for printed circuit boards, and the open ends of the silicone adhesive packing material for printed circuit boards are pressed together to adhere the board to the surrounding area.

[0012] In order to solve the above problems, the present invention also provides a method for using the silicone adhesive packing material for printed circuit boards as set forth in claim 1 or 2, which comprises the steps of: The printed circuit board is sandwiched between folded pieces of silicone adhesive packing material for printed circuit boards, and the peripheral edges of the silicone adhesive packing material for printed circuit boards are pressed together to bond them together.

[0013] Here, the printed circuit board and the silicone adhesive packing material for printed circuit boards in the claims may be singular or plural. The silicone adhesive packing material for printed circuit boards may be in sheet form, envelope form, bag form, etc., and may have high or low light transmittance. Furthermore, the term "automobile" includes at least four-wheeled vehicles (electric vehicles, fuel cell vehicles, hybrid vehicles, plug-in hybrid vehicles), golf carts, electric wheelchairs, motorcycles, etc. The term "seam joint" includes at least the architectural terms standing seam, small seam, flat seam, and rolled seam.

[0014] The silicone adhesive packing material for printed circuit boards according to the present invention can be used in vehicles, medical equipment, music equipment, home appliances, industrial equipment, office equipment, information equipment, precision equipment, electrical equipment, electronic equipment, transportation equipment, etc. The up-down, front-rear, left-right directions of the silicone adhesive packing material for printed circuit boards according to the present invention are directions based on the drawings and can be appropriately changed as necessary. Furthermore, although the subject of the present invention is a silicone adhesive packing material for printed circuit boards, if the configuration of other applications is the same as the configuration of the present invention and can be converted into a silicone adhesive packing material for printed circuit boards, and the effects of the present invention are achieved, the configuration of the other applications falls within the technical scope of the present invention.

[0015] According to the present invention, a printed circuit board on which electronic components are mounted is entirely wrapped and protected from the outside with a silicone adhesive packing material for printed circuit boards, which has excellent durability, weather resistance, corrosion resistance, heat resistance, chemical resistance, flame retardancy, dielectric properties, adhesion, water repellency, etc., so the printed circuit board is less likely to be damaged by foreign matter such as ions. Furthermore, if the silicone adhesive packing material for printed circuit boards is flexible and pliable before curing, there is less risk of restrictions being placed on the wiring and electrical connections of the printed circuit board. [Effects of the Invention]

[0016] According to the present invention, a printed circuit board on which electronic components are mounted is wrapped in a silicone adhesive packing for printed circuit boards, which has the effect of eliminating the risk of the printed circuit board being damaged by ions or the like, which could lead to circuit malfunction, and also has the effect of preventing restrictions on the wiring and electrical connections of the printed circuit board.

[0017] According to the invention of claim 2, when a printed circuit board is built into at least one of an automobile's ECU or e-axle, it is possible to prevent the performance of the printed circuit board from being reduced due to the adhesion of ions, dust, etc. from the ECU or e-axle to the printed circuit board. In addition, the lightweight silicone adhesive packing for printed circuit boards can contribute to the fuel consumption rate of automobiles and the power consumption rate of electric vehicles.

[0018] According to the invention of claim 3, when the silicone adhesive packing material for printed circuit boards is molded into a rubber sheet using a moisture-condensation curing silicone rubber composition, the silicone adhesive packing material for printed circuit boards can be cured by reacting with moisture in the air. Also, when the silicone adhesive packing material for printed circuit boards is molded into a rubber sheet using an addition-curing silicone rubber composition, the silicone adhesive packing material for printed circuit boards can be cured at room temperature.

[0019] When a silicone adhesive packing material for printed circuit boards is molded into a rubber sheet using a combination of a moisture-condensation-curing silicone rubber composition and an addition-curing silicone rubber composition, the silicone adhesive packing material for printed circuit boards can be cured at room temperature. When a silicone adhesive packing material for printed circuit boards is molded into a rubber sheet using a UV-curing silicone rubber composition, the silicone adhesive packing material for printed circuit boards can be easily cured by irradiating it with ultraviolet light. Furthermore, when a silicone adhesive packing material for printed circuit boards is molded into a rubber sheet using a radical polymerization silicone rubber composition, it can be rapidly cured in a short period of time.

[0020] When silicone adhesive packing materials for printed circuit boards are molded into rubber sheets using radical-condensation silicone rubber compositions, they can be cured by condensation even when UV light does not reach them. Furthermore, when silicone adhesive packing materials for printed circuit boards are molded into rubber sheets using polyimide-modified silicone rubber compositions, they can achieve high heat resistance. Furthermore, when silicone adhesive packing materials for printed circuit boards are molded into rubber sheets using epoxy-modified silicone rubber compositions, they can bond different materials and achieve excellent elasticity.

[0021] According to the invention of claim 4, when the silicone adhesive packing material for printed circuit boards is molded into a light-transmitting rubber sheet, visual inspection of the printed circuit board becomes easier, making it possible to quickly determine the condition of electronic components, etc. According to the invention of claim 5, all electronic components can be covered and protected by the silicone adhesive packing material for printed circuit boards, without having to adhere the silicone adhesive packing material for printed circuit boards to all electronic components or seal all electronic components with epoxy resin or the like.

[0022] According to the invention of claim 6 or 7, as the peripheral edges of the silicone adhesive packing material for printed circuit boards deteriorate, gaps will form between the opposing peripheral edges, preventing the passage of ions, dust, etc. According to the invention of claim 8, rather than overlapping and adhering the front, rear, left and right peripheral edges of the silicone adhesive packing for printed circuit boards, the open ends of the silicone adhesive packing for printed circuit boards are overlapped and pressed together to adhere, which reduces the number of adhesive points, making the work simpler, faster and easier and shortening the work time.

[0023] According to the invention of claim 9, rather than overlapping and adhering the peripheral edges of the front, back, left and right four sides of the silicone adhesive packing for printed circuit boards, only the peripheral edges of three sides are overlapped and adhered. This reduces the number of adhesive points, which is expected to simplify, speed up and facilitate the work, and shorten the work time. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a side view illustrating a silicone adhesive packing material for printed circuit boards according to an embodiment of the present invention and a method of using the same. FIG. [Figure 2] FIG. 1 is a perspective view showing a schematic diagram of a seam in an embodiment of a silicone adhesive packing material for printed circuit boards according to the present invention. [Figure 3] FIG. 2 is a perspective view showing a schematic diagram of a small seam in a second embodiment of a silicone adhesive packing material for printed circuit boards according to the present invention. [Figure 4] FIG. 1 is an explanatory diagram illustrating a schematic diagram of an electric vehicle and its e-axle. DETAILED DESCRIPTION OF THE INVENTION

[0025] A preferred embodiment of the present invention will now be described with reference to the drawings. As shown in Figure 1, multiple sheets of silicone adhesive packing material 10 for printed circuit boards in this embodiment encapsulate a printed circuit board 1 on which electronic components 3 are mounted to protect it from the outside, thereby contributing to the achievement of Goal 9 of the SDGs adopted at the United Nations Summit.

[0026] The printed circuit board 1 includes a printed circuit board 2 with positioning guide holes drilled in the four corners, etc., and a plurality of electronic components 3 of different sizes are electrically connected by solder to at least the surface of the printed circuit board 2 to form a printed circuit mounted product, which is built into, for example, a housing 22 of an e-axle 21 of an electric vehicle 20 shown in Figure 4. The plurality of components is not particularly limited, but may include, for example, the required number of LSIs, ICs, CPUs, transistors, diodes, resistor elements, capacitors, electrical connectors, etc.

[0027] The multiple sheets of silicone adhesive packing material 10 for printed circuit boards consist, for example, of a pair of opposing upper and lower silicone adhesive packing materials 10 for printed circuit boards, each formed into a flat rectangular sheet that is larger than the printed circuit board 2, and by sandwiching and enclosing the entire printed circuit board 1 on which multiple electronic components 3 are mounted from above and below, they function to effectively protect the printed circuit board 1 from various external ions (e.g., chloride ions, sulfate ions, phosphate ions, etc.), dust, etc.

[0028] Each silicone adhesive packing material 10 for printed circuit boards is formed into a translucent rubber sheet with optical transparency from a deoxime-type moisture-condensation curing silicone rubber composition that reacts with moisture in the air and cures at room temperature, and is formed to a thickness of 3 mm or less to exhibit excellent durability, weather resistance, corrosion resistance, heat resistance, chemical resistance, flame retardancy, dielectric properties, adhesion, water repellency, rubber elasticity, etc. This silicone adhesive packing material 10 for printed circuit boards is mainly formed into a flat rectangular rubber sheet, but the shape can be changed to a flat polygon or other shape depending on the shape of the printed circuit board 1, etc.

[0029] The physical properties of the silicone adhesive packing material for printed circuit boards (10) after curing are, for example, a hardness of 40 to 50, preferably around 45, measured at 23°C and 50% RH using JIS K6249 Type A; a tensile strength of 5.0 MPa to 6.0 MPa, preferably around 5.4 MPa, measured at 23°C and 50% RH using JIS K6249 No. 3 dumbbell; an elongation of 680% to 800%, preferably around 730%, measured at 23°C and 50% RH using JIS K6249 No. 3 dumbbell; and a tear strength of 11 N / mm to 20 N / mm, preferably around 16 N / mm, measured at 23°C and 50% RH using JIS K6249 Unnotched Angle Tester.

[0030] The thickness of the silicone adhesive packing material 10 for printed circuit boards is 3 mm or less from the viewpoint of preventing the circulation of various ions, dust, etc., but considering factors such as ease of manufacturing and handling, it is preferably 2.5 mm or less, and more preferably around 2 mm.

[0031] Of the pair of upper and lower silicone adhesive packing materials 10 for printed circuit boards, the upper silicone adhesive packing material 10 for printed circuit boards, which covers and contacts multiple electronic components 3, may contact some of the taller electronic components 3A, thereby forming gaps 11 between it and the remaining shorter electronic components 3B. Even if gaps 11 are formed between the upper silicone adhesive packing material 10 for printed circuit boards and the remaining shorter electronic components 3B, it still covers all of the electronic components 3, thereby effectively protecting the electronic components 3 from ions and the like, and there is no need to adhere it tightly to all of the electronic components 3 to protect them. Examples of molding methods for forming the silicone adhesive packing material 10 for printed circuit boards into a rubber sheet include calendar molding and extrusion molding.

[0032] Examples of such silicone adhesive packing material 10 for printed circuit boards include, but are not limited to, Polymer Ace (registered trademark) UG (product name, manufactured by Shin-Etsu Polymer Co., Ltd.) and Polymer Ace (registered trademark) PA (product name, manufactured by Shin-Etsu Polymer Co., Ltd.).

[0033] In the above, when encapsulating and protecting a printed circuit board 1 on which a plurality of electronic components 3 are mounted, a pair of soft, uncured silicone adhesive packing materials 10 for printed circuit boards is prepared, the printed circuit board 1 is sandwiched between the pair of silicone adhesive packing materials 10 for printed circuit boards, the peripheral edges 12 of the pair of silicone adhesive packing materials 10 for printed circuit boards are positioned opposite each other, and the peripheral edges 12 of the pair of silicone adhesive packing materials 10 for printed circuit boards are pressure-welded together without heating.

[0034] During this pressure welding, the peripheral edges 12 of a pair of silicone adhesive packing materials 10 for printed circuit boards can simply be overlapped and pressure welded together, but from the standpoint of preventing gaps from forming due to deterioration of the peripheral edges 12 over time, it is preferable to seam and pressure weld the front, rear, left, and right peripheral edges 12 of a pair of silicone adhesive packing materials 10 for printed circuit boards (see Figure 2). Specifically, it is preferable to fold the peripheral edges 12 of the pair of silicone adhesive packing materials 10 for printed circuit boards together and interlock them, and then press these interlocked vertical seams together with a roller or the like.

[0035] After the peripheral edges 12 of a pair of silicone adhesive packing materials 10 for printed circuit boards are pressed together, they are left to dry for a predetermined time, which causes each silicone adhesive packing material 10 for printed circuit boards to harden and adhere, encapsulating the printed circuit board 1 and preventing corrosion of the printed circuit board 1 by ions such as chloride ions, and in this state the printed circuit board can be installed and fixed in the housing 22 of the e-axle 21.

[0036] This eliminates the risk of circuit malfunction due to corrosion of the printed circuit board 1 caused by the migration of external ions such as chloride ions. Furthermore, since there is no need to mold a bulky resin case for the printed circuit board, dedicated molds, molding machines, and other equipment can be omitted, and space savings can be expected due to the omission of the resin case. Furthermore, because the silicone adhesive packing material 10 for printed circuit boards is flexible before curing, it can be deformed, thereby reducing restrictions on the wiring and electrical connections of the printed circuit board 1. For example, if an electrical connector is mounted on the printed circuit board 1, opening a connection hole for the electrical connector in the silicone adhesive packing material 10 for printed circuit boards before curing can improve the flexibility of wiring and electrical connections.

[0037] Furthermore, because the silicone adhesive packing material 10 for printed circuit boards is lightweight, when the printed circuit board 1 and the silicone adhesive packing material 10 for printed circuit boards are used in an electric vehicle 20, it can contribute to improving the power consumption of the electric vehicle 20. Furthermore, the peripheral edges 12 of a pair of silicone adhesive packing materials 10 for printed circuit boards can be integrated by simply self-adhering them at room temperature without the need for heat pressing, which eliminates warping of the printed circuit board 2 when heated and adverse effects on the electronic components 3. Furthermore, because a translucent silicone adhesive packing material 10 for printed circuit boards is used instead of a chromatic epoxy resin or the like, it becomes easier to inspect the appearance of the printed circuit board 1 from the outside, making it possible to quickly determine whether the electronic components 3 have deteriorated or corroded over time.

[0038] Furthermore, because the silicone adhesive packing material for printed circuit boards 10 is flexible before it hardens, it is possible to insert a fastener such as a screw into the silicone adhesive packing material for printed circuit boards 10 before it hardens and pass it through a positioning guide hole in the printed circuit board 1, and then screw the fastener into the housing 22 of the e-axle 21 to firmly position and fix the printed circuit board 1. Furthermore, because the silicone adhesive packing material for printed circuit boards 10 does not contain silica, a significant vibration suppression effect on the printed circuit board 1 can be expected.

[0039] Furthermore, when multiple printed circuit boards 1 are stored together in the e-axle 21 of the electric vehicle 20, noise between the printed circuit boards 1 can become a problem, but the silicone adhesive packing material 10 for printed circuit boards that encapsulates the printed circuit boards 1 also functions as an electromagnetic wave absorbing sheet, so appropriate noise countermeasures can be implemented.

[0040] 3 shows a second embodiment of the present invention, in which the peripheral edges 12 of a pair of silicone adhesive packing materials 10 for printed circuit boards are folded and interlocked, and the interlocked portions are seamed and pressed together with a roller, etc. The rest of the structure is the same as in the above embodiment, so a description thereof will be omitted.

[0041] This embodiment is expected to have the same effects as the above embodiment, and it is clear that it can prevent gaps from forming between the peripheral edges 12 of the silicone adhesive packing material 10 for printed circuit boards, and also shorten the length of the peripheral edges 12 required for seaming.

[0042] In the above embodiment, the silicone adhesive packing material 10 for printed circuit boards was molded into a translucent rubber sheet with light transmission from a moisture-condensation-curing silicone rubber composition. However, a translucent rubber sheet with light transmission may also be molded from an addition-curing silicone rubber composition that cures at room temperature and does not require heat press molding. A light-transmitting rubber sheet may also be molded from a combination of a moisture-condensation-curing silicone rubber composition and an addition-curing silicone rubber composition. A light-transmitting rubber sheet may also be molded from a UV-curing silicone rubber composition that cures when exposed to ultraviolet light.

[0043] Alternatively, the silicone adhesive packing material 10 for printed circuit boards may be formed into a rubber sheet using a radical polymerization type silicone rubber composition that can be expected to cure quickly, a convenient radical-condensation type silicone rubber composition that cures by condensation even when UV light does not reach, a polyimide-modified silicone rubber composition that excels in low elasticity and high heat resistance, or an epoxy-modified silicone rubber composition that excels in adhesion to different materials and elasticity.

[0044] Furthermore, in the above embodiment, one printed circuit board 1 is encapsulated by a pair of silicone adhesive packing materials 10 for printed circuit boards, but multiple stacked printed circuit boards 1 can be entirely encapsulated and protected by a pair of silicone adhesive packing materials 10 for printed circuit boards. Furthermore, the silicone adhesive packing material 10 for printed circuit boards does not need to form a gap 11 between itself and the low-profile electronic component 3B. Furthermore, while the above embodiment illustrates a printed circuit board 1 for an e-axle 21 of an electric vehicle 20, the present invention is not limited to this and may be, for example, a printed circuit board 1 for an ECU in various automobiles. Furthermore, the printed circuit board 1 may be a printed circuit board 1 for an air compressor for a brake on a railroad vehicle, a bicycle, a lawnmower, a boat, or the like.

[0045] Furthermore, when encapsulating and protecting a printed circuit board 1 on which a plurality of electronic components 3 are mounted, a tube-shaped silicone adhesive packing material 10 for printed circuit boards with both ends open is prepared, the printed circuit board 1 is fitted into this tube-shaped silicone adhesive packing material 10 for printed circuit boards, and the open ends of the silicone adhesive packing material 10 for printed circuit boards are overlapped and pressed together, and then left to dry at room temperature for a predetermined time, thereby hardening and bonding the silicone adhesive packing material 10 for printed circuit boards.

[0046] Furthermore, when encapsulating and protecting a printed circuit board 1 on which multiple electronic components 3 are mounted, a large silicone adhesive packing material 10 for printed circuit boards can be prepared, folded in half to sandwich the printed circuit board 1 therebetween, and the peripheral edges of the three opposing sides of the folded silicone adhesive packing material 10 for printed circuit boards are seamed and pressed together, and then left to dry for a predetermined period of time, allowing the silicone adhesive packing material 10 for printed circuit boards to harden and adhere at room temperature.

[0047] Furthermore, when encapsulating and protecting a printed circuit board 1 on which multiple electronic components 3 are mounted, it is possible to insert the printed circuit board 1 into the cured, bag-shaped silicone adhesive packing material 10 for printed circuit boards, press the top and bottom of the opening of the silicone adhesive packing material 10 for printed circuit boards, and leave it for a predetermined time to cure and adhere the opening of the silicone adhesive packing material 10 for printed circuit boards. Furthermore, all of the technologies described in this specification are subject to the acquisition of rights through amendments, divisional applications, etc. [Industrial Applicability]

[0048] The silicone adhesive packing material for printed circuit boards and its method of use according to the present invention can be used in the manufacturing fields of transportation, medical equipment, music equipment, household appliances, industrial equipment, information equipment, precision equipment, electrical equipment, electronic equipment, etc. [Explanation of symbols]

[0049] 1 printed circuit board 2. Printed circuit board 3. Electronic Components 3A electronic components 3B Electronic parts 10 Silicone adhesive packing material for printed circuit boards 11 Gap 12 Periphery 20 Electric Vehicles (Automobiles) 21 e-axle 22 Housing

Claims

1. A silicone adhesive packing material for printed circuit boards, characterized in that it is used to encapsulate printed circuit boards on which electronic components are mounted.

2. 2. The silicone adhesive packing material for printed circuit boards according to claim 1, wherein the printed circuit board is built into at least one of an ECU and an e-axle of an automobile.

3. 3. The silicone adhesive packing material for printed circuit boards according to claim 1 or 2, which is formed into a rubber sheet from a moisture-condensation-curing silicone rubber composition, an addition-curing silicone rubber composition or a combination thereof, a UV-curing silicone rubber composition, a radical-polymerization silicone rubber composition, a radical-condensation-curing silicone rubber composition, a polyimide-modified silicone rubber composition, or an epoxy-modified silicone rubber composition.

4. 4. The silicone adhesive packing material for printed circuit boards according to claim 3, which is molded into a light-transmitting rubber sheet.

5. 5. The silicone adhesive packing material for printed circuit boards according to claim 4, which is capable of forming a gap between a shorter electronic component and a taller electronic component on the printed circuit board by contacting the taller electronic component.

6. 3. A method for using the silicone adhesive packing material for printed circuit boards according to claim 1 or 2, comprising: A method for using a silicone adhesive packing material for printed circuit boards, characterized in that a printed circuit board is sandwiched between a pair of silicone adhesive packing materials for printed circuit boards, and the peripheral edges of the pair of silicone adhesive packing materials for printed circuit boards are pressed together to bond them together.

7. 7. A method for using the silicone adhesive packing material for printed circuit boards according to claim 6, wherein the peripheral edges of a pair of silicone adhesive packing materials for printed circuit boards are seamed and pressure welded together.

8. 3. A method for using the silicone adhesive packing material for printed circuit boards according to claim 1 or 2, comprising: A method for using a silicone adhesive packing material for printed circuit boards, comprising fitting a printed circuit board into a substantially tubular silicone adhesive packing material for printed circuit boards and then pressure-welding both open ends of the silicone adhesive packing material for printed circuit boards to adhere the board.

9. 3. A method for using the silicone adhesive packing material for printed circuit boards according to claim 1 or 2, comprising: A method for using a silicone adhesive packing material for printed circuit boards, characterized in that a printed circuit board is sandwiched between folded pieces of silicone adhesive packing material for printed circuit boards, and the peripheral edges of the silicone adhesive packing material for printed circuit boards are pressed together to bond them together.

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