JPS588636A - Photo polymerizing element wound in roll form - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photopolymerizable element wound into a roll for manufacturing flexible printed circuit boards.

Flexible printed circuit boards have various advantages over hard circuit boards. Firstly, it is flexible and highly flexible, allowing three-dimensional wiring to fit around five curved surfaces and corners.
Second, since it is thin, it can be made into a thin film, and third, it can be wired to moving objects. What is even more unique is that a reinforcing plate is applied to a part of the board to create a hard part, and 91 parts are mounted on it to serve as a hard board, while the part that is not reinforced can be used as a connection cable by taking advantage of its flexibility. The ability to use one board for different purposes.

Due to the advantages mentioned above, flexible printed circuit boards have been increasingly used in recent years.

The method of manufacturing a flexible printed circuit board is to apply a liquid resist to a flexible copper-clad board or to laminate a dry film resist under pressure, to create a desired pattern by image exposure and development, and finally to perform an etching process or The process involves plating to obtain the final metal pattern.

However, in the conventional method, in the case of a liquid resist, skill is required to apply it to a uniform thickness, and in the case of a dry film resist, when laminating it on a copper surface, vibrations of the laminating equipment and swivels of the film may occur. I was born 9, pasted on the copper surface 9
There are various inconveniences such as air being trapped when the product is attached.

In either case, a coating device and a laminating device are required.

The present invention overcomes the above drawbacks and relates to a photopolymerizable element for efficiently producing a flexible printed circuit board, which element comprises: (1) a protective film; (2) photopolymerizable resist formation It has flexibility, consisting of layers and (5) a flexible copper-clad substrate that are sequentially laminated, and is wound into a roll.

According to the element of the present invention, the resist forming layer is laminated on the flexible substrate from the beginning4, so there is no need for the conventional coating or laminating process, and there is no need for any equipment for that process, resulting in loss caused by that process. It is very efficient and convenient. Manufacturers of flexible printed circuit boards can manufacture printed circuit boards without traditional operations.

Moreover, such an element for manufacturing flexible printed circuit boards has not been invented to date.

The protective film used in the element of the present invention is preferably a film that can be easily peeled off from the resist forming layer. For example, a polyolefin film such as polyethylene or polypropylene, a biaxially oriented polyethylene terephthalate film, a polyamide film, a polyacetal film, etc. be.

When removing the protective film, the protective film must be selected so that the adhesion between the protective film and the resist forming layer is smaller than the adhesion between the resist forming layer and the copper surface.

The photopolymerizable resist forming layer has a structure in which it is sandwiched between a protective film and a flexible copper-clad substrate, and may be stored, so it is preferable to use a solid form from the viewpoint of handling.

As for the composition of the resist forming layer, the composition of a dry film resist is optimal, and the resist composition generally consists of: ■ an organic polymer binder, ■ an ethylenically unsaturated compound having two or more unsaturated bonds, and ■ a photopolymerization initiator. It is true. Specifically, 1% Publication No. 45-25231, JP-A-54-
The composition disclosed in Publication No. 18732 can be used.

The material used for the flexible copper-clad board is a base film such as a biaxially oriented polyethylene terephthalate film, a polyimide film, or a thin glass cloth film impregnated with epoxy resin, to which copper foil is bonded. The thickness of the film is 20-200μ.

The thickness of copper foil is generally 18 to 200μ.

This flexible board is not limited to one in which copper foil is bonded to one side; a double-sided copper-clad board in which copper foil is bonded to both sides of a base film can also be used. There are also elements with .

6 One element can be prepared by applying a photopolymerizable solution on the copper surface of a flexible copper-clad board, drying it, and laminating a protective film under pressure, or by applying a photopolymerizable solution on the protective film in the same way. After drying, the copper surface and the resist surface of the flexible copper-clad substrate are laminated under pressure to manufacture the substrate.

As described above, with the elements of the present invention, flexible printed circuit boards can be manufactured more easily and efficiently than with conventional methods.

Example 1 The following resist composition was prepared.

Polymethyl methacrylate (MW=120,000)
Sooo? trimethylolpropane triacrylate
300 f triethylene glycol diacetate 40? Benzophenone 30
f mi hira ke ton
10F Victoria Pure Blue 1F Methyl Ethyl Ketone
2000 f The above solution was coated from a resist solution tank (2 people) onto a biaxially stretched poly 6-ethylene terephthalate film (1) with a thickness of 25 μm and a width of 30 tM as shown in Figure 1, and then dried in a dryer (3A). ) and dried at 80° C. to form a resist layer (2) with a thickness of 25 μm. Then, the polyimide thickness of the base film is 100μ (4) S copper foil embedded 35μ
Figure 2 shows the cross section of this element, which was laminated under pressure on the flexible pull board (3) (5), wound up into a roll (6), and finally rolled up to 100 m. 30 of this element
It was cut into 15cm squares and exposed through a transparent image using an ultra-high pressure mercury lamp manufactured by Oak (Phoenix 3000. Output 3KW).
Exposure for seconds.

Next, the polyethylene terephthalate film was peeled off, and 1.1-trichloroethane was sprayed onto it using a shower device to remove the unexposed areas and form an image. Then, the exposed copper surface was etched away by immersion in a ferric chloride solution (Bohr 45°), leaving only the copper under the resist. Furthermore, this resist was removed with methylene chloride to obtain a copper pattern.

The obtained circuit board was flexible and had good flexibility, and no phenomena such as cracking of the circuit board occurred even when it was bent at 180°.

One Example 2 The following resist composition was prepared.

Polymethyl methacrylate) (MW=80,000) e
oo f trimethylolpropane triacrylate
150 f Tetraethylene glycol diacrylate 150t2-ethylanthraquinone
369 Crystal Violet 1f Methyl Ethyl Ketone 2000 was uniformly stirred into the above solution, and a 7 lexiple substrate with a width of 20tn1 (biaxially stretched polyethylene terephthalate 50μ,
Coat the copper foil (18μ) and dry to form a resist forming layer with a thickness of 20μ.
The biaxially oriented polypropylene films were laminated under pressure and wound once to obtain an element of the present invention.

This element was subjected to image exposure in the same manner as in Example 1.

A pattern was obtained by developing.

The resulting circuit board is flexible and highly flexible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for explaining the manufacturing process of the element of the present invention, and FIG. 2 is a partially sectional 8-sectional view of the element of the present invention. 1... Protective film 2... Resist layer 2...- Resist solution bath 3... Copper foil 3A... -... Dryer 4, River... Base film 5... Flexible copper-clad board 6...
・・・・・・ Photopolymerizable element wound into a roll Patent applicant Asahi Kasei Corporation

Claims (1)

[Scope of Claims] L A photopolymerizable element 2 wound into a roll formed by sequentially laminating (1) a protective film, (2) a photopolymerizable resist forming layer, and (5) a flexible copper-clad substrate. Forming layer (2) and flexible copper-clad substrate (
5) The photopolymerizable element λ wound into a roll according to claim 1, wherein the adhesive force with the protective film (1) is much greater than the adhesive force between the protective film and the resist forming layer. A photopolymerizable element book wound into a roll according to claim 1, which is a film that substantially transmits active light; Copper foil (
1-