JP2003334907A - Releasable multi-layer film and cover lay molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a releasable multi-layer film which significantly eliminates the exudation of a cover lay adhesive and the generation of FPC finish appear ance creases unsatisfactory in a conventional release single-layer film, while retaining outstanding characteristics such as releasability, shape followability FPC moldability and platability, and a cover lay molding method. <P>SOLUTION: In the releasable multi-layer film with two layers, that is, a releasable side layer and a releasable opposite side layer, the releasable side layer is formed of a polymethylpentene a copolymer of the polymethylpentene and an α-olefin and has a thickness of 10-50 μm. The opposite side layer is formed of a polypropylene or a mixture of a polyethylene and the polypropylene. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release multilayer film used in the manufacturing process of flexible printed wiring boards.

[0002]

2. Description of the Related Art Flexible printed wiring boards (hereinafter referred to as F
In the manufacturing process of (PC), a coverlay (hereinafter referred to as a heat-resistant resin film with an adhesive for the purpose of insulation and circuit protection) on an insulating substrate, for example, a flexible circuit board having a predetermined circuit on the surface of a polyimide resin film. , CL), and press lamination using a release film is usually performed. In this manufacturing process, the mold releasability between the FPC and the contact plate, the adhesive flow from the CL end face is suppressed by sufficiently following the irregularities of the FPC, the conductor is prevented from being contaminated, and the pressure is made uniform by wrapping the entire FPC. , That is, releasability, conformability to shape,
Devoid property due to uniform pressure on the entire FPC (hereinafter, F
In addition to the moldability of PC) and the wrinkle of the finished appearance of FPC, there is a demand for a release film that is excellent in plating on the circuit in the subsequent process.

[0003]

DISCLOSURE OF THE INVENTION The present invention is unsatisfactory with conventional release single-layer films while maintaining excellent properties such as releasability, conformability to shape, moldability of FPC, and plating property. Another object of the present invention is to provide a release multi-layer film which improves the appearance of the cover lay adhesive and the appearance of wrinkles on the finish of FPC, and a cover lay molding method using the same.

[0004]

Means for Solving the Problems The present invention provides a release multilayer film having two layers, a release side layer and a release opposite side layer, wherein the release side layer has a thickness of 10 to 50 μm, such as polymethylpentene or poly. A release multi-layer film comprising a copolymer of methylpentene and α-olefin, wherein the resin of the release-opposite side layer is polypropylene or a mixture of polyethylene and polypropylene; Point average roughness 70-2000
The release multilayer film according to [1], wherein the average surface roughness of the layer on the side opposite to the release is 70 to 20.
The release multilayer film according to [1] or [2], which has a thickness of 00 nm, in the manufacturing process of the flexible printed wiring board,
It is a coverlay molding method which uses the release multilayer film as described in [1] to [3] as a release film for coverlay press lamination.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The resin used in the release side layer of the present invention is polymethylpentene or a copolymer of polymethylpentene and α-olefin. Polymethylpentene is represented by the following formula (1).

[Chemical 1]

The copolymerization ratio of the copolymer of polymethylpentene and α-olefin and the type of α-olefin are not particularly limited.

The thickness of polymethylpentene or a copolymer of polymethylpentene and α-olefin is 10 to 50 μm.
m, and preferably 20 to 40 μm. Thickness is 1
If it is less than 0 μm, the polymethylpentene or the copolymer of polymethylpentene and α-olefin may be broken after press lamination, and when the FPC and the release multilayer film are separated, polymethylpentene or polymethyl may be added to the FPC side. A copolymer of pentene and α-olefin may remain. On the contrary, when the thickness exceeds 50 μm, the conformability to the shape is deteriorated, the flow amount of the adhesive adhering to the CL is increased, and the plating property is also insufficient. Further, when polypropylene is used for the release side layer, the conformability to the shape is deteriorated, the flow amount of the adhesive adhering to the CL is increased, and the plating property is insufficient.

The resin of the layer opposite to the mold release used in the present invention is polypropylene or a mixture of polyethylene and polypropylene. The types of polypropylene are random copolymers, homopolymers, and block copolymers.
When polypropylene or a mixture of polyethylene and polypropylene is used, the softening point is lower than that of a single-layer film using polymethylpentene or a copolymer of polymethylpentene and α-olefin, and the pressure applied to FPC is easily transmitted uniformly. , FPC moldability is improved. Also, in terms of cost, it can be manufactured at a lower cost than the above-mentioned monolayer film.

An adhesive resin may be interposed between the releasing side layer and the releasing side layer. The type of adhesive resin is not particularly limited, but examples thereof include maleic anhydride-modified polyolefin, nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, natural rubber, butyl rubber and the like.

The surfaces of the release-side layer and the release-opposing side layer of the present invention may be embossed in-line or off-line. The embossing treatment includes a method of passing the film through a mat roll at a high temperature and a high pressure, and a method of pressing the film coming out of the die against an embossing cooling roll with a touch roll. Regarding the method using the mat roll, the temperature is preferably 50 to 220 ° C, more preferably 100 to 190 ° C. The linear pressure applied to the roll is preferably 200 to 2500 N / cm, more preferably 230 to 2000 N / cm. Further, the roughness of the mat roll is 10-point average roughness (hereinafter abbreviated as Ra).
The thickness is preferably 0.05 μm to 1 mm, and the surface roughness of the film is preferably Ra = 70 to 2000 nm. Within this range, the appearance of wrinkles on the finish of the FPC will not occur, and the embossed pattern will not be transferred to the FPC.

The release multilayer film of the present invention may be produced by any method such as a coextrusion laminating method, an extrusion laminating method and a dry laminating method, and is not particularly limited.

The release multilayer film of the present invention is used for press laminating a cover lay in the FPC manufacturing process,
As a molding method for pressure lamination, for example, between hot plates,
SUS board, rubber cushion, release multilayer film, single-sided F
A structure in which a PC, a PP single layer film, and a SUS plate are stacked in this order is placed, and after heating and pressurizing under predetermined conditions, post-curing may be performed.

[0013]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The raw materials used in Examples and Comparative Examples are as follows. Copolymer of polymethylpentene and α-olefin (TP
X): Part number MX004 (manufactured by Mitsui Chemicals, Inc.) Homopolypropylene (PP): Part number FS2011DG
(Sumitomo Chemical Co., Ltd.) Polyethylene (PE): Part number L211 (Sumitomo Chemical Co., Ltd.)

The release multilayer film is extruded by supplying TPX as a release layer and PP and a mixture of PP and PE as an intermediate layer to two extruders in two extruders.
It was made by laminating and integrating. Moreover, in Examples 6 to 12,
A mat roll is used for the layer on the release side or the layer on the side opposite to the release, and Ra on the mat surface is 8.3, the temperature is 160 ° C., and the linear pressure is 14
The embossing treatment was performed under the condition of 00 N / cm. Next, a stainless plate, a rubber cushion, the prepared release multilayer film, a single-sided FPC, a PP single layer film, and a stainless plate were laminated, and a multi-stage press machine was used.
After pressure molding at 0 ° C. and 30 kg / cm ² for 60 minutes, pressure cooling was performed until the temperature reached 50 ° C., and the following evaluation items were evaluated. The types, characteristics and evaluation results of the resins used in the examples and comparative examples are shown in Table 1 and Table 2, respectively. The evaluation is JPC
It complies with the A standard (design guide manual, single-sided and double-sided flexible printed wiring board, JPCA-DG02).

Formability (JPCA-DG02 7.5.
Section 3.3, "Bubbles") A: Void generation rate less than 2.0% X: Void generation rate 2.0% or more CL adhesive flow amount (JPCA-DG02 7.5.
Section 3.6, “Flow of adhesive on coverlay and bleeding of cover coat” ○: Flow amount less than 150 μm ×: Flow amount 150 μm or more Exudation amount of film end face (resin exudation from the film end face after pressing) Length: ◯: Exudation amount less than 5 mm ×: Exudation amount 5 mm or more Finished appearance wrinkle (JPCA-DG02 7.5.7.
Item 2, "wrinkle") ◎: Wrinkle occurrence rate less than 1.0% ○: Wrinkle occurrence rate 1.0 or more, less than 2.0% ×: Wrinkle occurrence rate 2.0% or more Film (release side layer) (Due to “7.5.7.1” of JPCA-DG02, “adhesion on the surface”) ○: Breakage occurrence rate less than 2.0% ×: Breakage occurrence rate 2.0% or more Platability (required plating) Goods with 90% or more of the area plated are good: JPCA-DG02 7.5.
According to item 4, “Appearance of plating” ○: 98% or more of non-defective products ×: Less than 98% of non-defective products

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

INDUSTRIAL APPLICABILITY As described above, the present invention is a release multilayer film having excellent properties as a release film for cover lay press lamination in the process of manufacturing a flexible printed wiring board. Depending on the lay molding method, releasability, conformability to shape, moldability of FPC,
It was possible to remarkably improve the appearance of wrinkles of the cover lay adhesive and the wrinkle of the finished appearance of the FPC, which were unsatisfactory with the conventional release single-layer film, while maintaining excellent characteristics of plating property.

Claims (4)

[Claims] 1. A release multi-layer film having two layers, a release side layer and a release opposite layer, wherein the release side layer has a thickness of 10 to 50.
μm polymethylpentene or polymethylpentene and α
A release multi-layer film comprising a copolymer with an olefin, wherein the resin in the layer opposite to the release layer is polypropylene or a mixture of polyethylene and polypropylene. 2. The 10-point average roughness of the surface of the release side layer is 70.
The release multilayer film according to claim 1, which has a thickness of ˜2000 nm. 3. The release multilayer film according to claim 1, wherein the surface of the layer opposite to the release has a 10-point average roughness of 70 to 2000 nm. 4. A cover lay molding method in which the release multilayer film according to claim 1 is used as a release film for cover lay press lamination in the process of manufacturing a flexible printed wiring board.