JPH0766996B2 - Flexible printed circuit board and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flexible printed circuit board, and more particularly to a flexible printed circuit board having a relatively small shape, which is thin and highly flexible, and a manufacturing method thereof. is there.

"Prior Art" Conventionally, a flexible printed circuit board manufacturing means in which a plurality of small, thin, and highly flexible printed circuit boards are arranged on a base sheet in an easily peelable state for the purpose of improving workability during mounting. For example, JP-A-60
-31290 and Japanese Patent Laid-Open No. 60-52082, individual flexible printed circuit boards are separated by cutting all unnecessary portions of one flexible substrate on which a plurality of flexible printed circuit boards are formed. In order not to be in such a state, remove appropriate parts by leaving some parts for temporary connection,
Then, on the back side of the flexible printed circuit board,
The flexible printed circuit boards are bonded with a base sheet, etc., which has the most convenient width and has been treated with an appropriate adhesive so that the individual flexible printed circuit boards are connected, and then the individual flexible printed circuit boards There is a means to obtain a finished product by cutting and removing the unnecessary connecting portion left in order to keep the connected state.

In a certain type of flexible printed circuit board in the "problem to be solved by the invention", a pressure-sensitive adhesive layer is provided in advance on the back surface of a necessary portion such as a terminal portion or a flexible portion, and by this pressure-sensitive adhesive, There is one in which a flexible printed circuit board is mounted by being adhered to a device. In this case, if the flexible printed circuit board is divided into individual pieces, it takes time to peel off small and thin release paper, and punching process and inspection process due to unnecessary sticking between products. Etc., the handling is likely to be complicated.

In order to eliminate such inconvenience, for example, Japanese Patent Laid-Open No. 60-3129
There were inventions such as JP-A No. 0 and JP-A-60-52082, and attempts were made to eliminate the above-mentioned drawbacks, which resulted in a considerable improvement, but the manufacturing process was rather complicated, and the release paper was also fundamental. The peeling work cannot be omitted during the manufacturing process or when mounting the product.

The present invention solves the problems of the prior art,
A flexible printed circuit board and a method of manufacturing the flexible printed circuit board, which are developed mainly for the purpose of automatically peeling a small, thin release paper which is difficult to peel off at the time of mounting.

"Means for Solving the Problems" That is, the flexible printed circuit board of the present invention is one in which a plurality of required flexible printed circuit boards are arranged on one base sheet with an adhesive mount partially interposed therebetween. The adhesive mount is one in which a pressure-sensitive adhesive layer is formed on one surface of a release paper via a release agent treatment layer, and a heat-sensitive adhesive layer is formed on the back surface, and the pressure-sensitive adhesive layer is a flexible printed circuit board. Of the heat-sensitive adhesive layer is thermocompression-bonded to a base sheet, and the overlapping portion of the pressure-sensitive adhesive layer and the flexible printed circuit board have the same shape. (See FIG. 4, which will be described later).

Further, the method for manufacturing a flexible printed circuit board according to the present invention uses one flexible base material on which a plurality of flexible printed circuit boards to be products are formed, and a release paper is attached to a predetermined portion in contact with the flexible printed circuit board. A base that covers an adhesive layer with a release agent treatment layer on one side and an adhesive mount with a heat-sensitive adhesive layer on the back side with the heat-sensitive adhesive layer on the outside, and then covers the flexible substrate on the outside. Sheets are stacked, the adhesive layer is adhered to a predetermined portion of the flexible printed circuit board, and the heat-sensitive adhesive layer is thermocompression-bonded onto the base sheet, and then the base is formed along the necessary outer circumference of the flexible printed circuit board. Do not cut the sheet, but cut the flexible printed circuit board and the adhesive layer to obtain the required flexible printed layer with adhesive layer. It is characterized in that arranged on the base sheet substrate plurality, in an easily peelable state (see below Fig. 1 - Fig. 4).

[Operation] (Refer to Examples below) In the flexible printed circuit board of the present invention, when mounting, the individual flexible printed circuit boards with the adhesive layer are automatically transferred from the base sheet to the protective paper of the adhesive layer. Flexible printed circuit board with necessary adhesive layer removed (the release paper is strongly thermocompression bonded to the base sheet with a heat-sensitive adhesive, and the adhesive layer is peeled off from the release paper by the release agent treatment layer) Only can be stripped off.

Further, in the method for manufacturing a flexible printed circuit board according to the present invention, in order to prevent the flexible printed circuit board from being separated individually during the conventional manufacturing process, "the product is suitable for a flexible printed circuit board during product cutting. Such a connection part is left → The position of each flexible printed circuit board is kept as it is by pasting the base sheet etc. → To keep the connection initially, the unnecessary part that retains the cutting is removed. The method is simplified by using a pressure-sensitive adhesive layer having adhesive strengths different from each other on both sides or a pressure-sensitive adhesive mount having adhesive layers formed on both sides and a conventional technique of half-cutting.

In the product and the manufacturing method of the present invention, the flexible printed circuit board and thus the flexible base material are, as is well known, a base film, an adhesive, and a conductor (copper) coverlay (insulating layer) forming a wiring pattern. )) (See FIG. 4 described later).

Further, as the base sheet, for example, a paper sheet having a thickness of about 50 to 200 μm, a plastic sheet such as polypropylene or polyethylene terephthalate is used.

As the release agent on one surface of the release paper, a release agent such as silicone is used.

The pressure-sensitive adhesive layer is formed using, for example, a rubber-based, acrylic-based, or silicone-based pressure-sensitive adhesive.

As the heat-sensitive adhesive layer, for example, polyolefin-based,
A resin based on a polyamide-based or rubber-based resin that does not become sticky at room temperature, has adhesiveness at about 80 to 120 ° C., and has an adhesive layer thickness of about 10 to 50 μm is used.

"Examples" Hereinafter, the present invention will be described in detail with reference to Examples in order to facilitate understanding of the present invention.

FIG. 4 shows a sectional view of the flexible printed circuit board of the present invention (a sectional view of a completed product). This flexible printed circuit board of the present invention can be manufactured by the manufacturing method of the present invention described later.

In FIG. 4, (2) is a flexible printed circuit board, which is, as is well known, a base film (10), an adhesive (11), and a conductor (copper) (12) forming a wiring pattern. , A coverlay (insulating layer) (13). (5) is a base sheet.

(4) is an adhesive mount between the flexible printed circuit board (2) and the base sheet (5), and this adhesive mount has an adhesive layer (8) on the release agent (6) application side on the upper surface of the release paper (7). )
However, a heat-sensitive adhesive layer (9) is formed on the opposite surface.

The product of the present invention shown in FIG. 4 is made up of a plurality of flexible printed circuit boards fixed on a base sheet with an adhesive mount. When peeling and separating individual flexible printed circuit boards from this product for mounting (for example, sucking around the middle of the product without the adhesive mount), only the necessary adhesive layer is added to the back surface of the flexible printed circuit board. In this state, the work of removing the release paper for protecting the adhesive is unnecessary. (The release paper is strongly thermocompression-bonded to the base sheet by the heat-sensitive adhesive and remains on the base sheet.) Next, the production method of the present invention will be described.

In FIG. 1, one flexible base material (1) is formed with a plurality of flexible printed circuit boards (2) to be products according to a conventional method. As an example, it is assumed that this flexible printed circuit board is required to have an adhesive material layer having a required strength required for mounting only the back surface of the terminal portion shown in (3).

FIG. 2 is a preferred embodiment of the present invention, in which an adhesive mount (4) is provided on the back surface of the flexible printed circuit board corresponding to the terminal portion shown in (3), and a flexible substrate is provided on the lower surface of the adhesive mount as shown. Base sheets (5) having the same dimensions as the width of the material are laminated.

FIG. 3 is a cross-sectional view showing the structure of the adhesive mount (4) only, showing the necessary adhesive strength on the release agent treated side of the release paper (7) treated on one side with the silicone type release agent (6). The acrylic pressure-sensitive adhesive layer (8) is provided, and the olefin heat-sensitive adhesive layer (9) is formed on the opposite surface.

The process of manufacturing the flexible printed circuit board of the present invention is
Flexible printed circuit board (2) as shown in FIG.
Adhesive mount (4) explained in detail in Fig. 3 on the required parts of
Is laminated underneath with a base sheet (5) having an appropriate rigidity and heated and laminated at 100 ° C. with a slight pressure (as a result, the heat-sensitive adhesive produces an adhesive force by heating. Power increases).

The base material with the base sheet, which has been integrated through the above steps, is half-cut along the outer periphery of the required flexible printed circuit board (2) to the depth of the board (2) and the adhesive layer (8). Therefore, the overlapping portions of the adhesive layer and the flexible printed circuit board have the same shape.

Depending on the shape, structure, etc. of the product, there may be a case where the necessary punching and partial peripheral punching are performed in any step before the half-cutting.

In addition, during this half-cutting process, the total thickness of the appropriate position is appropriately adjusted for the purpose of facilitating the subsequent removal of unnecessary portions of the flexible printed circuit board and the work of peeling off the individual flexible printed circuit boards from the finished product. Sometimes punching and increasing the number of half cuts.

Thus, by half cutting, unnecessary parts of the substrate are removed from the semi-finished product to obtain a finished product. FIG. 4 is a sectional view of the finished product.

As described above, according to the production method of the present invention, the pressure-sensitive adhesive layer and the adhesive layer (specifically, the pressure-sensitive adhesive (8) and the heat-sensitive adhesive layer (9)) having different adhesive strengths are formed on both surfaces. The product can be easily obtained by using the adhesive mount and the technique of half-cut.

In FIGS. 1 and 2, the flexible printed circuit board (2) and the flexible base material (1) are the base film (10), the adhesive material (11), and the wiring as described in FIG. Although it is composed of a conductor (copper) (12) and a coverlay (insulating layer) (13) that form a pattern, it is illustrated in a simplified manner.

"Effects of the Invention" As described above, the flexible printed circuit board of the present invention has effective advantages described in (a) and (b) below in the subsequent steps such as mounting the flexible printed circuit board.

Further, the production method of the present invention has the effective advantages described in the following item C.

(1) Especially when manufacturing and mounting flexible printed circuit boards that are small, thin, and highly flexible, there is no work to remove thin release paper with a small area, and it is easy to handle, reducing man-hours. , Yield improvement can be expected.

(B) Since the flexible printed circuit board is arranged on the base sheet in a continuous and easily peelable manner, the above mounting work is also an example. Makes automation easy.

(C) The production method of the present invention is a conventional production method developed in expectation of the above effects (a) and (b).
0-52082 etc.), I) the manufacturing process is simple, II) there is no trouble such as transfer of the adhesive due to the first unnecessary part cutting and its removal work, and III) completed product Since it is always lined with the entire base sheet, it maintains the desired rigidity as a whole and the position accuracy of each flexible printed circuit board is good. This is convenient for automating the work of peeling off the flexible printed circuit board and the operation of adding necessary parts to the flexible printed circuit board.

[Brief description of drawings]

FIG. 1 is a perspective view of a flexible substrate on which a plurality of flexible printed circuit boards are formed, and FIG. 2 is
In the process of manufacturing the flexible printed circuit board of the present invention, a perspective view of a substrate, an adhesive mount and a base sheet that are superposed, FIG. 3 is a sectional view showing the structure of the adhesive mount shown in FIG. FIG. 4 exemplifies a cross-sectional view of the finished product of the present invention (a cross-sectional view of the finished product cut at a position corresponding to the position of the line AA in FIG. 2 showing the manufacturing process). . (1) ... Flexible substrate, (2) ... Flexible printed circuit board, (3) ... Terminal part, (4) ... Adhesive mount, (5) ... Base sheet, (6) ... Release Agent,
(7) ... Release paper, (8) ... Adhesive, (9) ... Heat sensitive adhesive.

Claims (2)

[Claims] 1. A plurality of required flexible printed circuit boards are arranged on one base sheet with an adhesive mount partially interposed therebetween, the adhesive mount being separated from one side of a release paper. A pressure-sensitive adhesive layer is formed via a mold treatment layer, and a heat-sensitive adhesive layer is formed on the back surface. The pressure-sensitive adhesive layer is adhered to a predetermined portion of the flexible printed circuit board, and the heat-sensitive adhesive layer is A flexible printed circuit board, which is formed by thermocompression bonding to a base sheet, and has the same shape in the overlapping portion of the adhesive layer and the flexible printed circuit board. 2. A single flexible substrate on which a plurality of flexible printed circuit boards to be products are formed,
At a predetermined portion in contact with the flexible printed circuit board, an adhesive layer is provided on one surface of the release paper via a release agent treatment layer,
An adhesive backing sheet having a heat-sensitive adhesive layer formed on the back side is laminated with the heat-sensitive adhesive layer as the outer side, and then a base sheet covering the flexible base material is further laid on the outer side thereof, and the pressure-sensitive adhesive layer is provided on the flexible printed circuit board in a predetermined manner. Stick to the part,
Also, the heat-sensitive adhesive layer is thermocompression-bonded on the base sheet,
After that, along the required outer circumference of the flexible printed circuit board, do not cut the base sheet, but cut the flexible printed circuit board and the adhesive layer to easily obtain the required flexible printed circuit board with the adhesive layer. A method of manufacturing a flexible printed circuit board, characterized in that the flexible printed circuit board is arranged on a base sheet in a peelable manner.