JPH02139216A - Method of forming three-dimensional molded circuit - Google Patents

Abstract

PURPOSE:To prevent a circuit from peeling from the surface of a molded body or cracking by a method wherein electrically conductive paste, the binder of which is a thermosetting resin, is printed along the predetermined circuit pattern onto the inner surface of an injection mold and then brought into a semi-cured state by heating the mold and, after that, a thermosetting resin, which is the same one employed as the binder, is injected in the mold. CONSTITUTION:Electrically conductive paste 3, the binder of which is thermosetting resin, is printed along the predetermined circuit onto the inner surfaces of injection molds 1 and 2 and then brought into semi-cured state 3' by heating the molds and, after that, thermosetting resin, which is the same one employed as the binder, is injection-molded in the molds 1 and 2 so as to obtain a molded body P having the desired three-dimensional shape. Thus, a product, in which a circuit 3'' produced through the curing of the electrically conductive pastes 3 and 3' is transferred to the surface of the molded body P, is obtained. As the electrically conductive paste 3, low-temperature curing silver paste or copper paste, the binder of which is phenolic or epoxy-based thermosetting resin or the like, is preferably used.

Description

Translated fromJapanese

【発明の詳細な説明】〔卒業上の利用分野〕本発明は、電気接続箱や計器盤などの電気機器のケース
の壁面を利用して立体成形回路を形成する方法に関する
。DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a method for forming a three-dimensional molded circuit using the wall surface of a case of an electrical equipment such as an electrical connection box or an instrument panel.

〔従来の技術〕[Conventional technology]

従来、立体成形回路を形成する方法として、第２図ない
し第４図に示すように、導電性ペーストや金属蒸着法な
どにより回路ａを形成した転写フィルムｂを射出成形金
型ｃ　、　ｃ’内にセットし、注入口ｄから樹脂ｅを射
出充填し、この射出成形と同時に転写フィルムｂ上の回
路ａを成形体Ｐに転写する方法がある。Conventionally, as shown in Figs. 2 to 4, a method for forming a three-dimensional molded circuit is to transfer a transfer film b on which a circuit a is formed using a conductive paste or a metal vapor deposition method into injection molds c and c'. There is a method in which the resin e is injected and filled from the injection port d, and the circuit a on the transfer film b is transferred to the molded body P at the same time as this injection molding.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

従来の転写成形方法では、回路（導体）ａが剛性を有す
るため、立体形状への追従性が悪く、導体の亀裂発生や
導体が完全に転写されない場合があり、不良品が生じや
すい欠点があった。In conventional transfer molding methods, because the circuit (conductor) a has rigidity, it has poor followability to three-dimensional shapes, and there are cases where cracks occur in the conductor and the conductor is not completely transferred, resulting in the production of defective products. Ta.

本発明の課題は、かかる欠点のない立体成形回路の形成
方法を提供することにある。An object of the present invention is to provide a method for forming a three-dimensional molded circuit without such drawbacks.

〔課題を解決するための手段〕[Means to solve the problem]

図面を参照して説明すると、本発明の立体成形回路の形
成方法は、第１図ａ　−ｄに示すように、射出成形金型
１，２の内面に、熱硬化性樹脂をバインダとする導電性
ペースト３を所定の回路に沿って印刷し、金型の加熱に
より前記導電性ペーストを半硬化状態３′にした後、金
型１，２内に前記バインダと同種の熱硬化性樹脂４を射
出成形して所望の立体形状を有する成形体Ｐを得ること
を特徴とする。To explain with reference to the drawings, the method for forming a three-dimensional molded circuit according to the present invention is as shown in FIGS. 1a to 1d. After printing the conductive paste 3 along a predetermined circuit and making the conductive paste into a semi-hardened state 3' by heating the mold, a thermosetting resin 4 of the same type as the binder is placed in the molds 1 and 2. The method is characterized in that a molded article P having a desired three-dimensional shape is obtained by injection molding.

これにより、成形体Ｐの表面に導電性ペースト３　（３
’　）の硬化により形成された回路３“が転写された製
品が得られる。As a result, the conductive paste 3 (3
A product having the circuit 3'' formed thereon is obtained by curing the circuit 3''.

第１図ａにおいて、５はシリコンゴム類のパッドを示し
、その弧状面５ａに予め所定の回路パターンに沿って導
電性ペースト３を塗布しておく。In FIG. 1a, reference numeral 5 indicates a pad made of silicone rubber, and a conductive paste 3 is previously applied to the arcuate surface 5a of the pad along a predetermined circuit pattern.

導電性ペースト３は、フェノール系、エポキシ系などの
熱硬化性樹脂をバインダとする低温硬化型の銀ペースト
や銅ペーストを用いるのが好ましい。As the conductive paste 3, it is preferable to use a low-temperature curing type silver paste or copper paste using a thermosetting resin such as a phenol type or an epoxy type as a binder.

第１図ａのように、パッド５を下金型１の内面１ａに押
しつ・けるなどの方法により、所定の回路パターンを有
した導電性ペースト３を印刷する。As shown in FIG. 1a, a conductive paste 3 having a predetermined circuit pattern is printed by pressing the pad 5 against the inner surface 1a of the lower mold 1.

印刷された導電性ペースト３は、第１図すのように、下
金型１の加熱により半硬化状態３′になる。加熱温度は
１５０〜２００°Ｃとくに１７０〜１８０°Ｃの範囲が
好ましい。The printed conductive paste 3 becomes a semi-hardened state 3' by heating the lower mold 1, as shown in FIG. The heating temperature is preferably in the range of 150 to 200°C, particularly 170 to 180°C.

次いで、第１図Ｃのように上金型２をセットし、その注
入口２ａから樹脂４を射出成形する。樹脂４は前記導電
性ペースト３のバインダと同種の熱硬化性樹脂を用いる
。射出成形は１００〜１０００ｋｇ／ｃｆｆｌ、とくに
２００〜５００ｋｇ／ｃ艷の低中圧力下で行うのが好ま
しい。射出圧力が高すぎると、導電性ペースト３′の位
置ずれが発生し、また低すぎると硬化後に良好な導電性
が得られない。Next, the upper mold 2 is set as shown in FIG. 1C, and the resin 4 is injected from the injection port 2a. As the resin 4, the same type of thermosetting resin as the binder of the conductive paste 3 is used. The injection molding is preferably carried out under a low to medium pressure of 100 to 1000 kg/cffl, particularly 200 to 500 kg/cffl. If the injection pressure is too high, misalignment of the conductive paste 3' occurs, and if it is too low, good conductivity cannot be obtained after curing.

成形後、金型１，２から第１図ｄのように成形体Ｐを取
り出すと、成形体表面に回路３“が転写、埋設された立
体成形回路体が得られる。After molding, when the molded body P is taken out from the molds 1 and 2 as shown in FIG.

なお、この成形体Ｐは電気接続箱を構成する下部ケース
として形成した例を示し、その鍔縁部ｐには回路３“か
ら延設されたラウンド状の接続部３ａが設けられている
。Note that this molded body P is shown as an example formed as a lower case constituting an electrical connection box, and a round-shaped connection portion 3a extending from the circuit 3'' is provided on the flange portion P thereof.

（作　用）回路３“の初期形成は、柔軟な導電性ペースト３を直接
金型の内面に印刷（または塗布）することにより行われ
るから、亀裂の発生や追従性の悪さといった従来技術の
欠点が解消する。(Function) The initial formation of the circuit 3'' is performed by directly printing (or coating) the flexible conductive paste 3 on the inner surface of the mold, which eliminates the drawbacks of the conventional technology such as the occurrence of cracks and poor followability. is resolved.

導電性ペースト３は、射出成形樹脂４と同種のバインダ
を使用しているから、成形中に両者の界面で熱硬化性樹
脂特有の架橋反応が進行し、回路と成形樹脂とが強固に
化学結合する。Since the conductive paste 3 uses the same type of binder as the injection molding resin 4, the crosslinking reaction peculiar to thermosetting resins proceeds at the interface between the two during molding, creating a strong chemical bond between the circuit and the molding resin. do.

従って、回路３“と成形体表面との密着性がきわめて良
好な回路体が得られる。Therefore, a circuit body with extremely good adhesion between the circuit 3'' and the surface of the molded body can be obtained.

また、金型１，２内の成形圧力により導電性ペースト３
　（３’　）の硬化収縮が促進され、導電性が向上する
とともに、導電性ペーストの硬化が成形中に行われるの
で生産性が向上する。In addition, the conductive paste 3 is
Curing shrinkage of (3') is promoted, improving conductivity, and since the conductive paste is hardened during molding, productivity is improved.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、本発明によれば、転写フィルムは
不要であり、回路の成形体表面からの剥がれや亀裂のな
い信頼性の高い立体成形回路が得られるとともに、回路
を構成する導電性ペーストの硬化を樹脂の射出成形と同
時に行うことができるので生産性も向上する。As explained above, according to the present invention, there is no need for a transfer film, and a highly reliable three-dimensional molded circuit without peeling or cracking from the surface of the molded circuit can be obtained, and a conductive paste constituting the circuit can be obtained. Since curing can be performed simultaneously with injection molding of the resin, productivity is also improved.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図ａ　％　ｄはそれぞれ本発明の一実施例を示し、
ａ　”−’　ｃは立体成形回路の形成過程の説明図、ｄ
はその成形体の斜視図、第２図は従来の転写フィルムの平面図、第３図は第２図
のＩＩ［−ＩＩｌ線断面図、第４図は従来の成形方法の
説明図である。１・・・下金型、２・・・上金型、３，３′・・・導電
性ペースト、３“・・・回路、４・・・熱硬化性樹脂、
５・・・パッド、Ｐ・・・成形体。Figures 1a and 1d each show an embodiment of the present invention;
a ''-' c is an explanatory diagram of the formation process of the three-dimensional molded circuit, d
2 is a plan view of a conventional transfer film, FIG. 3 is a sectional view taken along the line II[-IIl in FIG. 2, and FIG. 4 is an explanatory diagram of a conventional molding method. DESCRIPTION OF SYMBOLS 1... Lower mold, 2... Upper mold, 3, 3'... Conductive paste, 3"... Circuit, 4... Thermosetting resin,
5... Pad, P... Molded object.

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]射出成形金型の内面に、熱硬化性樹脂をバインダとする
導電性ペーストを所定の回路パターンに沿って印刷し、
金型の加熱により前記導電性ペーストを半硬化状態にし
た後、金型内に前記バインダと同種の熱硬化性樹脂を射
出して所望の立体形状を有する成形体を得ることを特徴
とする立体成形回路の形成方法。A conductive paste containing a thermosetting resin as a binder is printed along a predetermined circuit pattern on the inner surface of an injection mold.
A three-dimensional structure characterized in that after the conductive paste is semi-hardened by heating a mold, a thermosetting resin of the same type as the binder is injected into the mold to obtain a molded article having a desired three-dimensional shape. How to form a molded circuit.