JPH0621594A - Integral printed circuit board molded form and manufacture thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] The printed wiring board sheet and the injection-molded body are firmly adhered to each other, and they can withstand high temperatures during the mounting of electronic and electrical components, and do not swell or delaminate Provided is a printed wiring board molded body. [Structure] A one-component curing type epoxy adhesive is applied to the other surface of a plastic composite having a circuit formed on one surface to a predetermined thickness, and this is mounted on an injection molding die to form an aromatic compound. An integrated printed wiring board molded body obtained by subjecting a polyamide resin to injection molding on an adhesive surface and then subjecting it to heat treatment under predetermined conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated printed wiring board molding by injection molding and a method for manufacturing the same.
Particularly, when an electronic component is mounted by soldering or the like, an integrated printed wiring board molded body excellent in heat resistance, which does not cause swelling or delamination between the molded body and the plastic composite with circuit, and the manufacturing thereof Regarding the method.

[0002]

2. Description of the Related Art In recent years,
BACKGROUND ART Electrical products such as audios, computers, 8 mm video, and mobile phones have advanced in performance, and along with this, there is an increasing need for miniaturization, weight reduction, and thinning. Printed circuit board wiring boards for such electrical products have conventionally been made of a copper foil on the surface of an electrically insulating base material such as glass-based epoxy resin or paper-based phenolic resin having a rigid property, or a flexible base material such as polyimide or polyester. And the like are attached, and then a circuit is formed by etching (subtractive method), or a circuit is formed on a substrate by electroless plating or electrolytic plating (additive method).

In recent years, as a method of manufacturing a printed wiring board, a method has been used in which an injection-molded resin molded body is electrolessly plated, etched to form an electric circuit, and a solder resist is provided thereon. ing.

In the above method, the printed wiring board can be formed into a three-dimensional shape without being limited to a flat surface, and therefore the wiring board itself can be used as a part of the housing or a part of parts. In addition, there is an advantage that holes for mounting a wiring board and mounting electric parts can be simultaneously formed by injection molding.

However, in the above method, it is necessary to perform metal plating, etching, and further solder resist processing on the printed wiring board molded body having a desired three-dimensional shape, which is a problem that the process is complicated. is there.

In order to solve the above-mentioned problems, a so-called printed wiring board sheet having a conductive circuit formed therein is inserted into an injection molding die and injection-molded to form a three-dimensional printed wiring board. A method for manufacturing a body has been proposed (Japanese Patent Laid-Open No. 2-7592).

However, the printed wiring board molded body formed by the above method has a high temperature of about 250 ° C. when mounting an electronic component by soldering, so that the temperature between the injection molded body and the printed wiring board is increased. There is a problem that swelling and delamination easily occur.

Therefore, the object of the present invention is that the sheet of the printed wiring board and the injection-molded article are firmly adhered to each other and can withstand the high temperature at the time of mounting the electronic / electrical parts without causing swelling or delamination An object is to provide an integrated printed wiring board molded body and a method for manufacturing the same.

[0009]

As a result of intensive studies in view of the above object, the present inventors have found that a one-component curing type epoxy adhesive is applied to the other surface of a plastic composite having a circuit formed on one surface. Molded into an integrated printed wiring board by applying it to a specified thickness, mounting it in an injection mold, injection molding aromatic polyamide resin on the adhesive surface, and then heat-treating it under specified conditions. The body has a good adhesion between the plastic composite and the aromatic polyamide molding, and even if electronic parts are mounted on the circuit surface by soldering, the plastic composite and the aromatic polyamide molding are The present invention was conceived by finding that swelling, delamination, etc. do not occur on the surface.

That is, the integrated printed wiring board molded body of the present invention is formed by integrally molding a plastic composite body having a predetermined pattern circuit formed on one surface and an aromatic polyamide molded body via an adhesive layer. A printed wiring board molded body obtained by forming the above-mentioned adhesive layer from a one-component curing type epoxy adhesive, having a thickness of 5 μm or more. Characterized by heat treatment for up to 10 hours.

Further, the method of the present invention for producing the above-mentioned integral type printed wiring board molded body includes (a) an adhesive on the surface opposite to the circuit of the plastic composite body having a predetermined pattern circuit formed on one surface. Is applied to form an adhesive layer having a thickness of 5 μm or more, and (b) the plastic composite is placed in the cavity of an injection molding die at 100 to 150 ° C. with the adhesive layer side facing outward. Then, (c) an aromatic polyamide is injection-molded to form an aromatic polyamide molded body on the adhesive layer of the plastic composite, and (d) the obtained integral molded body is coated with 100
It is characterized in that it is subjected to a heat treatment at a temperature of 150 ° C for 1 to 10 hours.

The present invention will be described in detail below. As illustrated in FIG. 1, an integrated printed wiring board molded body 1 of the present invention
Is formed by adhering the plastic composite 2 and the aromatic polyamide resin molded body 3 with the adhesive layer 4.

As shown in FIG. 2, the plastic composite body 2 used in this integrated type printed wiring board molded body is as follows.
The base film 21, and the pattern circuit 22 on one surface thereof,
In addition, an insulating resin layer is provided on the outside of the circuit except for the junction points
23 are provided.

The base film 21 is not particularly limited, but it is preferable that the base film 21 has heat resistance and is excellent in flexibility, flexibility, and insulation because the electronic parts are welded with solder or the like. , For example, glass-based epoxy resin, paper-based rigid resin such as phenol resin, polyethylene terephthalate, polyester such as polyethylene-2,6-naphthalate, polyether sulfone, polyether ether ketone, aromatic polyamide, polyarylate, A flexible film made of polyimide, polyamideimide, polyetherimide, polyphenylene sulfide (PPS), or a plastic such as a halogen group- or methyl group-substituted product thereof can be used. Of these, a polyimide film is particularly preferable.

The base film 21 as described above has a thickness of 20.
˜300 μm is preferable, and 35 to 200 μm is particularly preferable.

The pattern circuit 22 formed on the base film 21 can be formed using a conductive material such as copper or aluminum by a conventional method such as a subtractive method or an additive method. The circuit can also be formed by a screen printing method using a conductive ink.

The insulating resin layer 23 is formed by screen-printing a resin such as polyester, acrylic or polyurethane on the entire circuit pattern, and then a hole is formed at a predetermined position of the circuit by a photoresist method or the like to form a circuit. It may be formed by exposing the bonding point.

An electromagnetic wave shield layer may be formed on the surface opposite to the circuit, if necessary. The electromagnetic wave shield layer may be formed of a metal such as copper by a vapor deposition method, an electrolytic plating method, an electroless plating method, or the like.

Aromatic polyamide resin is used as the resin that substantially forms a molded product by injection molding, because heat resistance is required. Examples of the aromatic polyamide resin include poly-m-phenylene isophthalamide,
Polyamide 6T or the like can be used. Aromatic polyamides have an aromatic ring in the basic skeleton, as compared with aliphatic polyamides such as nylon 66, so they have a high melting point and high rigidity, and have improved water absorption, which is a drawback of aliphatic polyamides. is there.

In the present invention, for the purpose of further improving the heat resistance of the aromatic polyamide resin, it is possible to use a mixture of an inorganic filler such as glass fiber or talc. The compounding amount of the above-mentioned inorganic filler is 100 in total of the aromatic polyamide resin + the inorganic filler.
The weight% is preferably 10 to 50% by weight, particularly preferably 15 to 40% by weight. If the content of the inorganic filler is less than 10% by weight, the heat resistance cannot be sufficiently improved by the addition, and
When the content exceeds the weight%, not only the moldability is deteriorated but also the appearance is deteriorated, which is not preferable.

As an adhesive for joining such a plastic composite and an aromatic polyamide resin molding,
A one-component curing type epoxy adhesive is used. The one-component curing type epoxy adhesive basically contains an epoxy resin and a curing agent. The epoxy resin has two or more epoxy groups in the molecule (for example, epi-
(Bis type, polyether type, glycidyl ester type, etc.) are preferably used. The curing agent is preferably an anionic one such as a boron trifluoride complex compound, dicyandiamide, an organic acid anhydride, or diaminodiphenyl sulfone.

Further, it is preferable that the epoxy resin and the curing agent contain an elastomer component for the purpose of relaxing the internal stress generated when the adhesive force of the adhesive is developed. As the elastomer component, an olefin-based elastomer, various other rubber-based elastomers, or the like can be used, but since the adhesive strength is particularly good,
It is preferable to use an olefin elastomer.

The composition of the adhesive containing the above-mentioned elastomer component is such that the total amount of the epoxy resin + curing agent + elastomer component is 100% by weight, and the epoxy resin is 35 to 35%.
It is preferably 45% by weight, 5 to 15% by weight of curing agent and 40 to 50% by weight of elastomer component. The adhesive preferably comprises 20 to 30% by weight of solid content (epoxy resin + curing agent + elastomer component) and 70 to 80% by weight of solvent. As the solvent, it is preferable to use a ketone solvent such as methyl isobutyl ketone (MIBK).

The thickness of the adhesive layer as described above is 5 μm or more, preferably 5 to 15 μm. The thickness of the adhesive layer is 5
If it is less than μm, it becomes difficult to firmly bond the plastic composite and the aromatic polyamide resin molded body.

Next, a method for producing the integrated printed wiring board molded product of the present invention using the plastic composite, the aromatic polyamide resin and the adhesive will be described.

First, the above-mentioned adhesive is applied to the surface of the plastic composite opposite to the circuit surface. The amount of adhesive applied can be appropriately set so that the thickness of the adhesive layer is desired.

Subsequently, the plastic composite is placed in the cavity of the injection mold and injection molding is performed. An outline of an injection molding apparatus to which the method of the present invention using such a resin can be applied is shown in FIG.

In FIG. 3, the injection molding die 30 is a male die.
It consists of 31 and female mold 32, and when male 31 and female mold 32 are closed,
A cavity 33 is formed. Male 31
Has a slippery surface (Teflox, etc.), and various three-dimensional surfaces are formed according to the inner wall surface of the integrated printed wiring board molding. Such a ring-shaped through hole 34 is opened. on the other hand,
A gate 35 is provided at the center of the female die 32. The male die 31 is movable in the left-right direction in the figure with respect to the female die 32.

In such an apparatus, first, the male die 31 is set to the retracted position (moved from the position in FIG. 3 to the right side), the male die 31 and the female die 32 are opened, and the plastic die 31 is made of plastic. The composite 36 is placed with the adhesive layer on the outside.
By sucking air through the through hole 33, the plastic composite body 36 installed on the male die 31 is held in a state of being perfectly positioned on the surface of the tip portion of the male die. The plastic composite 36 is preferably pre-molded in advance so as to conform to the shape of the male mold.

At this time, the temperature of the mold is 100 to 150 ° C, preferably 110 to 130 ° C. If the mold temperature is less than 100 ° C, it will be difficult to firmly bond the plastic composite and the aromatic polyamide resin molded product, while if it exceeds 150 ° C, the base film will be curled or wrinkled. Easier to do.

Next, the male die 31 is advanced and connected to the female die 32.
(Figure 3). As a result, the gap between the two is completely closed, and the cavity 33 is in a sealed state. Then, the molten aromatic polyamide resin is injected through the gate 35 into the cavity 33 formed between the plastic composite 36 and the female mold 32. At this time, the resin temperature is preferably 300 to 350 ° C, and particularly preferably 320 to 330 ° C.

After the injection molding is completed and cooled in this way,
The male die 31 retracts (moves from the position in Fig. 3 to the right), and ejector pin or stopper plate (not shown)
By the action, the mold release is performed, and an integrated printed wiring board molded body can be obtained.

In this embodiment, the integrated printed wiring board molded body is subjected to a heat treatment for the purpose of strengthening the bonding between the plastic composite and the polyamide resin by the adhesive layer. . Heat treatment condition is 10
0 to 150 ° C, 1 to 10 hours, preferably 100 to 120 ° C
And, it is 1 to 3 hours. If the heat treatment temperature is less than 100 ° C, it will be difficult to firmly bond the plastic composite and the aromatic polyamide resin molded product, while if it exceeds 150 ° C, the film due to decomposition of the components of the adhesive and the like. Blisters are likely to occur. If the heat treatment time is less than 1 hour, it becomes difficult to firmly bond the plastic composite and the aromatic polyamide resin molded body,
On the other hand, if it exceeds 10 hours, the production efficiency will decrease. The heat treatment may be performed in an oven or the like.

In the integrated printed wiring board molded body of the present invention thus obtained, the plastic composite having a circuit and the aromatic polyamide which substantially forms the molded body are firmly bonded via the adhesive layer. Since it is adhered to the substrate, delamination or swelling does not occur even when exposed to high temperature by soldering or the like.

[0035]

In the integrated printed wiring board molding of the present invention, a one-component curing type epoxy adhesive is applied to a predetermined thickness on the other surface of a plastic composite having a circuit formed on one surface,
This is mounted on an injection molding die, and an aromatic polyamide resin is injection-molded on the adhesive surface, and then heat-treated under predetermined conditions. It is firmly adhered to the molded body,
Even if the electronic component is mounted on the circuit surface by soldering, swelling or delamination does not occur between the plastic composite and the aromatic polyamide molded body.

Although the reason why such an effect is obtained is not always clear, the one-component curing type epoxy resin adhesive has excellent adhesiveness to both the aromatic polyamide excellent in heat resistance and the plastic composite. This is considered to be good, and it is considered that, by performing heat treatment under the conditions of the present invention after injection molding of the aromatic polyamide, the adhesiveness between them, particularly the heat resistant adhesiveness, becomes even better.

[0037]

The present invention will be described in more detail with reference to the following specific examples. Example 1 Polyimide film (manufactured by Toray Industries, Inc .: Kapton, thickness 25)
After forming a conductive circuit made of copper with a thickness of 8 μm on one surface of the resin by a subtractive method, a portion other than the junction point of the circuit was covered with resist ink (insulating resin layer) to prepare a plastic composite.

A one-component curing type epoxy adhesive (manufactured by ThreeBond Co., Ltd .: 1570) was applied to the surface of the plastic composite thus obtained opposite to the circuit in a thickness of 7 μm.

The plastic composite thus obtained was mounted on a male mold of an injection molding mold at 130 ° C. so that the adhesive layer was on the outside, and after completion of the mold clamping, the aromatic polyamide
(Modified polyamide 6T, Aren A315 manufactured by Mitsui Petrochemical Co., Ltd.) was injected at 330 ° C. to obtain a molded product.

Then, the obtained molded body was placed in an oven.
Heat treatment was performed at 120 ° C. for 3 hours. Electronic components were mounted on the thus-obtained integrated printed wiring board molded body by soldering, and soldering suitability was evaluated. The results are shown in Table 1 together with the type of adhesive, the thickness of the adhesive layer, the type of resin for injection molding and the heat treatment conditions.

Examples 2 and 3 and Comparative Examples 1 to 9 The same as Example 1 except that the type and thickness of the adhesive as shown in Table 1 were used and the injection molding resin shown in Table 1 was used. To produce an integrated printed wiring board molded body.

The integrated printed wiring board compact thus obtained was placed in an oven and heat-treated under the conditions shown in Table 1. Electronic components were mounted on the thus-obtained integrated printed wiring board molded body by soldering, and soldering suitability was evaluated. The results are shown in Table 1 together with the type of adhesive, the thickness of the adhesive layer, the type of molding resin and the heat treatment conditions.

Table 1 Adhesive Layer Adhesive Type Thickness (μm ) Injection Molding Resin Example 1 1570 7 Modified Polyamide 6T Example 2 1570 5 Modified Polyamide 6T Example 3 1570 10 Modified Polyamide 6T Comparative Example 1 1570 2 Modified Polyamide 6T Comparative Example 2 1570 5 Modified Polyamide 6T Comparative Example 3 1570 5 Polyamide 66 Comparative Example 4 1570 5 Polyarylate Comparative Example 5 1570 5 Polybutylene Terephthalate Comparative Example 6 1570 5 Polysulfone Comparative Example 7 1570 5 Polyethersulfone Comparative Example 8 Polyester-based ⁽¹⁾ 5 Modified Polyamide 6T Comparative Example 9 Vinyl chloride-based ⁽²⁾ 5 Modified Polyamide 6T Note) (1): As a polyester-based adhesive, Toyobo Co., Ltd.
Made by Byron. (2): Showa Ink Co., Ltd. PVHS is used as a vinyl chloride-vinyl acetate copolymer adhesive.

Table 1 (continued) Heat treatment conditions Electronic component soldering temperature (° C) Time (hr ) Mounting suitability evaluation ⁽¹⁾ Example 1 120 3 ○ Example 2 120 3 ○ Example 3 120 3 ○ Comparative example 1 120 3 × Comparative Example 2 80 10 × Comparative Example 3 120 3 × Comparative Example 4 120 3 × Comparative Example 5 120 3 × Comparative Example 6 120 3 × Comparative Example 7 120 3 × Comparative Example 8- ⁽²⁾ - ^{(2 )} × Comparative example 9 − ⁽²⁾ − ⁽²⁾ × Note) (1) Evaluation of soldering mountability of electronic parts: After mounting electronic parts, the reflow condition was 230 ° C for 10 seconds, and peeling and swelling were observed. The evaluation is made by ◯ when it is not possible, and x when it is recognized as either peeling or swelling. (2): No heat treatment was applied.

[0045]

As described in detail above, in the integrated printed wiring board molding of the present invention, the one-component curing type epoxy adhesive is applied to the other surface of the plastic composite having the circuit formed on one surface. It is obtained by applying heat treatment under prescribed conditions after applying it to an injection molding die, injection-molding an aromatic polyamide resin on the adhesive surface, and applying it to an injection molding die. The composite and the aromatic polyamide molded body are firmly adhered, and swelling or delamination occurs between the plastic composite and the aromatic polyamide molded body even when electronic components are mounted on the circuit surface by soldering. Etc. does not occur.

The integrated printed wiring board molded body of the present invention as described above is particularly suitable for the field of miniaturized electronic products.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of an integrated printed wiring board molded body of the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of the layer structure of a plastic composite used in the integrated printed wiring board molded body of the present invention.

FIG. 3 is a cross-sectional view schematically showing an example of an injection molding die used for manufacturing an integrated printed wiring board molded body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Integrated printed wiring board molded body 2, 36 ... Plastic composite body 3 ... Aromatic polyamide molded body 4 ... Adhesive layer 21 ... Base film 22 ... Pattern circuit 23 ... Insulating resin layer 30 ... Injection mold 31 ... Male mold 32 ... Female mold 33 ... Cavity 34 ... Through hole 35 ... Gate

Claims (3)

[Claims] 1. A printed wiring board molded body obtained by integrally molding a plastic composite body having a predetermined pattern circuit formed on one surface and an aromatic polyamide molded body via an adhesive layer, The adhesive layer is made of a one-component curing type epoxy adhesive, has a thickness of 5 μm or more, and is formed by subjecting the printed wiring board molded body to heat treatment at 100 to 150 ° C. for 1 to 10 hours. An integrated printed wiring board molded body. 2. The integrated printed wiring board molded body according to claim 1, wherein the one-component curing type epoxy adhesive is
An integrated printed wiring board molded article comprising an epoxy resin, an anionic curing agent, and an elastomer. 3. (a) An adhesive agent is applied to a surface of a plastic composite having a predetermined pattern circuit formed on one surface thereof on the side opposite to the circuit to form an adhesive layer having a thickness of 5 μm or more,
(b) The plastic composite is placed in the cavity of an injection mold at 100 to 150 ° C with the adhesive layer side facing outward, and (c) the aromatic polyamide is injection-molded to form the plastic composite. Aromatic polyamide molding is formed on the adhesive layer of the body, and (d) 100-150 ° C is added to the obtained monolithic molding.
Then, a method for manufacturing an integrated printed wiring board molded body, characterized by performing heat treatment for 1 to 10 hours.