JP3634020B2

JP3634020B2 - Method and apparatus for producing epoxy resin castings

Info

Publication number: JP3634020B2
Application number: JP20447695A
Authority: JP
Inventors: 聡槙島; 雅文武井; 俊之中野; 以知郎市川; 康需金指
Original assignee: ティーエム・ティーアンドディー株式会社
Priority date: 1995-08-10
Filing date: 1995-08-10
Publication date: 2005-03-30
Anticipated expiration: 2015-08-10
Also published as: JPH0955119A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えばガス遮断器などの電力機器に用いる絶縁スペーサや樹脂モールドコイルなどのエポキシ樹脂注型品の製造方法および装置に関する。
【０００２】
【従来の技術】
一般に、重電機器は、充電部である導体などの金属部分をエポキシ樹脂などの絶縁体によって支持している。この場合、エポキシ注型材料は、エポキシ樹脂にアルミナやシリカ粒子などの無機充填剤を混合し調整された主剤と、硬化剤より成る。樹脂混合工程は、製品何個分かの主剤をまとめて調整した後、攪拌を継続し、充填剤の分散と樹脂温度を維持しながら次工程を待ち、注型金型に製造に必要な条件が整うと、必要量の主剤と硬化剤を混合し樹脂注入を行う。このため従来の技術では主剤を予め多量に調整するため、製品毎に主剤の混合履歴が異なる樹脂の注型が行われていた。
【０００３】
【発明が解決しようとする課題】
ところで、エポキシ樹脂中で無機充填剤を混練すると、充填剤の精製工程で残留したイオン性の不純物が溶出する。この不純物イオンは樹脂硬化の際、触媒として反応に作用し、反応速度にばらつきを生ずる原因となる。しかし、従来の技術では、主剤混合の条件管理ができないために樹脂の反応速度にばらつきを生じ、注型製品の品質を一定に保つことが困難であった。たとえば、主剤混合時間が長く不純物イオン濃度の高くなった樹脂で注型した製品は、同じ硬化温度および時間を与えても反応が速くなり離型時の反応率が高くなる。その結果、このような樹脂で注型した製品では、金型内での体積収縮も大きくなって残留歪が発生し、クラック等の機械的欠陥や部分放電等の電気的欠陥が発生する恐れがある。一方、主剤混合時間が短く不純物イオン濃度の低い樹脂で注型した製品は、離型時の反応率が低くなり強度が低下するため、離型の際の応力により製品に機械的欠陥を生じやすい。
【０００４】
以上の課題を回避するため、製品毎にその都度主剤を混合調整することも理論上は可能であるが、実際にそのような方法を行うと、製品に合わせて混合設備を用意したり、混合調整の度に洗浄工程が必要になったりして、生産性を著しく損なうおそれがあった。
【０００５】
本発明の目的は、前記のような従来技術の問題点を解決したエポキシ樹脂注型品の製造方法および装置を提供することにあり、より具体的には、エポキシ注型樹脂調整中に発生するイオン成分の濃度をコントロールし、樹脂の反応性を精密に管理することにより、製品品質の安定化を図ったエポキシ樹脂注型品の製造方法および装置を提供することにある。
【０００６】
【課題を解決するための手段】
請求項１の発明は、エポキシ樹脂に無機充填剤を混合し撹拌して主剤を生成する工程と、この主剤に硬化剤を添加し硬化剤添加樹脂を生成する工程と、この硬化剤添加樹脂を金型内で注型する工程と、この注型された前記樹脂を硬化する工程とを含むエポキシ樹脂注型品の製造方法において、前記主剤の混合時に樹脂の誘電特性を計測し、この計測結果に基づいて前記エポキシ樹脂と無機充填剤との混合時間または温度の少なくとも一方を制御することを特徴とする。この場合、混合時間の制御は、連続する撹拌作業時間を変更するか、撹拌作業を間欠的に行うことにより達成される。
【０００７】
このような構成を有する請求項１の発明では、主剤の誘電特性を検出することにより、エポキシ樹脂の反応速度に影響を与える充填剤に由来するイオン濃度を監視でき、主剤と充填剤との混合時間や温度を制御することでそのイオン濃度を所定の値に保持することが可能となる。その結果、混合方式、混合羽形状、混合槽内温度分布などが異なる樹脂撹拌設備を用いても、エポキシ樹脂の反応速度を所望の値に制御することができ、
請求項２の発明は、前記のような工程を含むエポキシ樹脂注型品の製造方法において、硬化剤添加樹脂の誘電特性を計測し、硬化剤添加後の樹脂の可使用時間を判定することを特徴とする。このような構成を有する請求項２の発明では、注入前の樹脂の特性が把握できるので、安定した材料管理が可能となる。
【０００８】
請求項３の発明は、前記のような工程を含むエポキシ樹脂注型品の製造方法において、主剤または硬化剤添加樹脂の少なくとも一方の誘電特性を計測し、この計測結果に基づいて金型内に注型された樹脂の硬化時間または硬化温度の少なくとも一方を制御することを特徴とする。このような構成を有する請求項３の発明では、たとえ主剤や硬化剤添加樹脂の反応性にばらつきを生じても、後の樹脂硬化工程を制御することによって反応性を改善し、製品の品質を保つことができる。
【０００９】
請求項４の発明は、前記のような方法を採用したエポキシ樹脂注型品の製造装置において、エポキシ樹脂に無機充填剤を混合し撹拌する主剤混合部と、この主剤混合部に設けられたエポキシ樹脂と無機充填剤の撹拌装置と、この主剤混合部に設けられて主剤の誘電特性を計測する誘電特性検出部と、前記誘電特性検出部からの検出値に基づいて前記撹拌装置の運転を制御する撹拌制御部と、
前記主剤混合部から供給された主剤に硬化剤を添加する硬化剤添加部と、この硬化剤添加部に設けられて硬化剤添加樹脂の誘電特性を検出する誘電特性検出部と、前記誘電特性検出部からの検出値に基づいて硬化剤添加樹脂の可使用時間を判定する可使用時間判定部と、
前記硬化剤添加部から供給された硬化剤添加樹脂を注型する金型と、この金型に設けられたヒータと、前記主剤混合部の誘電特性検出部と硬化剤添加部の誘電特性検出部とに接続されかつこれら誘電特性検出部からの検出値に基づいて前記金型に設けられたヒータの温度と金型内に注型した硬化剤添加樹脂の硬化時間とを設定する注型制御部とを備えていることを特徴とする。
【００１０】
このような構成を有する請求項４の発明によれば、主剤混合部に設けられた誘電特性検出部によってエポキシ樹脂と無機充填剤の混合時における誘電特性を検出し、この検出値を撹拌制御部に入力する。この撹拌制御部が前記検出値に基づいて主剤混合部に設けられた撹拌装置の運転時間を制御することにより、主剤のイオン濃度を所定の値に設定する。また、主剤混合部の誘電特性検出部は、混合作業によって得られた主剤の誘電特性の検出値を注型制御部に入力することにより、この主剤を金型に注型した場合の反応速度を判断し、注型時における適切な硬化時間を設定すると共に、ヒータを制御して金型を加熱することにより適切な反応温度を設定する。同様に、硬化剤添加部に設けられた誘電特性検出部によって硬化剤添加樹脂の誘電特性を検出し、この検出値を注型制御部に入力することにより、注型時における硬化時間と金型温度とを制御する。
【００１１】
また、硬化剤添加部に設けられた誘電特性検出部によって硬化剤添加樹脂の誘電特性を検出し、この検出値を可使用時間判定部に入力することにより、硬化剤を添加した主剤の可使用時間、すなわちポットライフを管理する。
【００１２】
【発明の実施の形態】
以下、本発明の実施の形態の一つを図面を参照して説明する。
【００１３】
（１）実施の形態の構成
図１は本発明によるエポキシ樹脂注型品の製造装置を示す構成図である。この実施の形態において、主剤混合部は、エポキシ樹脂と無機充填剤の注形材料主剤混合槽（プリミキサー）１を備えている。この主剤混合槽１には、攪拌装置としてモーター２によって回転する攪拌羽根３が設けられている。このモーター２には、その回転速度、運転時間、運転間隔を設定する攪拌制御部４が接続されている。この主剤混合槽１は配管５を介して硬化剤添加部を構成するファイナルミキサー６に接続されている。このファイナルミキサー６には、前記主剤混合槽１と同様に、モーター７によって回転する攪拌羽根８が設けられている。ファイナルミキサー６は配管９を介して注型金型１０に接続されている。この注型金型１０は、真空槽１１内に格納されており、配管９に接続された樹脂の注入口１２と、樹脂の硬化反応時に金型を所定の温度に加熱するヒーター１３を備えている。
【００１４】
前記主剤混合槽１には、その内部に供給されたエポキシ樹脂と無機充填材の誘電特性を検出するセンサー１４が設けられている。このセンサー１４は、主剤の誘電特性検出部１５に接続され、この誘電特性検出部１５が前記攪拌制御部４に接続されている。また、前記ファイナルミキサー６にも、その内部の樹脂の誘電計測用のセンサー１６が設けられている。このセンサー１６も硬化剤添加樹脂の誘電特性検出部１７に接続され、この誘電特性検出部１７に可使用時間判定部１８が接続されている。また、注型金型１０部分には、そのヒーター１３の温度を設定すると共に、金型内における樹脂の硬化時間を設定する注型制御部１９が接続され、この注型制御部１９に前記主剤混合槽１とファイナルミキサー６に接続された誘電特性検出部１５，１７が接続されている。
【００１５】
前記のような誘電特性計測用のセンサー１４，１６の一例を図２に示した。図２の３種のセンサーはポリマー計測用センサーで、（Ａ）がセラミックプレート２１上に櫛形電極２０を設けたセンサー（マイクロメット社製）、（Ｂ）がポリイミドフィルム２２上に櫛形電極２０を設けたフィルム状センサー（同社製商品名ＩＤＥＸセンサー）、（Ｃ）がガード２３表面に設けられたセラミック２４に櫛形電極２０を支持させた機器装着型センサー（同社製商品名ＴＭＳセンサー）である。これらのセンサーは、外形は異なっていてもその基本的な作用は同一であって、センサーに設けられた櫛形電極２０間に入った樹脂の誘電損失係数を計測するものである。
【００１６】
（２）実施の形態の作用
前記のような構成を有する本実施の形態の作用は次の通りである。
【００１７】
まず、エポキシ樹脂と無機充填材とを主剤混合槽１内に供給し、モーター２を駆動して攪拌羽根３を回転させることで混合する。この際、センサー１４に接続された誘電特性検出部１５によって、混合中の樹脂の誘電特性を検出する。一般に、ポリマーなどの誘電体においては、Ｄｅｂｙｅの双極子理論より誘電損失係数ε”は次式（１）で表され、
【数１】
ε”＝（ε_ｌ−ε_ｈ）ωτ／（１＋ω^２τ^２）…（１）
ε_ｈ：非緩和誘電率（高周波誘電率）
ε_ｌ：緩和誘電率（低周波誘電率）
τ：双極子緩和時間
ω：角周波数２πｆ
さらに伝導電流が流れる場合、電気伝導率をσ、真空の誘電率をε_０とすれば、ε”は次式で表される。
【数２】

（２）式において、周波数が十分低くωτ＜＜１の場合には、第２項を無視することができ、次の（３）式が得られる。
【数３】
ε”＝σ／（ωε_０） …（３）
よって電気伝導率σおよびその逆数である等価抵抗率ρは近似的に以下（４）（５）式で表される。
【数４】
σ＝ε”ε_０ω …（４）
【数５】
ρ＝１／σ＝１／ε”ε_０ω …（５）
【００１８】
図３にはエポキシ注型樹脂主剤混合中の電気伝導率の経時変化を示す。計測周波数１Ｈｚとし計算は（４）式による。エポキシ注型樹脂は、ビスフェロールＡ型エポキシ樹脂（チバガイギー社製：ＣＴ２００，エポキシ当量３９０）９０重量部、脂環式エポキシ樹脂（チバガイギー社製：ＣＹ−１７５）１０重量部に対し、充填剤として粒子状アルミナ（昭和電工社製：平均粒径１２μｍ）２５０重量部を配合し、主剤混合槽１にて１２０℃で真空混合した。混合中、充填剤から発生するアルカリ金属等の不純物イオンの影響で、樹脂中の電気伝導率が上昇する。発生するイオンの種類が同じであるならば電気伝導度はイオン濃度に比例する。従来の通常混合の場合、混合時間とともにイオン濃度が増加し、樹脂硬化の際、イオン性物質が触媒として反応に作用し、反応速度にばらつきを生ずる原因となる。
【００１９】
そこで、本実施の形態においては、主剤混合時の樹脂中のイオン濃度が一定になるよう充填剤の沈降を防止する程度に撹拌条件を制御する。すなわち、前記センサーの出力値を誘電特性検出部１５において判定し、この検出部１５に接続されている攪拌制御部４によって撹拌羽根３の回転数を低下させるか間欠撹拌を行う。本実施の形態では、主剤混合槽１に間欠撹拌を導入し混合時の樹脂の誘電特性をセンサー１４で監視して、電気伝導率が３×１０^−１０Ω・ｃｍになるように制御した。その結果、図３中に点線で示したように、樹脂の混合により成分の分散が得られたら充填剤の沈降が生じない程度に穏やかな撹拌条件を与えることにより、イオンの濃度を一定に保つことができる。
【００２０】
次に、前記のようにして得られた主剤は、配管５を通ってファイナルミキサー６に送られ、そこで硬化剤と混合された後、配管９および注入口１２を通って注型金型１０内に送り込まれる。注型金型１０には、注型制御部１９が設けられており、この注型制御部１０に前記主剤混合槽１およびファイナルミキサー６の誘電特性検出部１５，１７が接続されているため、この誘電特性検出部１５，１７からの信号により、ヒーター１３の温度を設定し、注型金型１０内における樹脂の反応温度を制御する。また、硬化時間も前記誘電特性検出部１５，１７からの信号により樹脂内のイオン濃度を判定して、それに応じた硬化時間を設定する。その結果、主剤の混合後の経時変化したり、硬化剤添加時における攪拌作業により樹脂内のイオン濃度が主剤の混合完了時点から変化しても、金型内で樹脂が製品毎に常に一定の硬化速度を得られるようヒータ温度を変化させたり、常に同じ硬化度で離型するよう硬化時間を可変制御することができる。また、各工程で使用される種々の混合撹拌設備の撹拌効率が異なっても、誘電特性検出部からの指令によりイオン濃度を管理することができる。
【００２１】
また、本実施の形態では、ファイナルミキサー６に設けられた誘電特性検出部１７に可使用時間判定部１８が接続されているので、ファイナルミキサー内に貯留されている硬化剤添加樹脂の誘電特性を検出することにより、その可使用時間を判定することができる。すなわち、硬化剤を添加した樹脂をファイナルミキサー６内に放置した場合に、徐々に硬化反応が進んでいくが、樹脂が硬化すると樹脂中のイオン成分の動きが拘束され等価抵抗率の上昇として硬化の進行を検知することができる。
【００２２】
（３）他の実施の形態
本発明は、図示の実施の形態に限定されるものではなく、誘電特性計測によるモニタリングは、ファイナルミキサー中の主剤、硬化剤の混合条件の管理や金型内部での樹脂硬化工程の管理に使用することができる。また、工程中にさらに主剤混合条件に偏差を生じ反応性に異常が起きても注型金型内部での樹脂の誘電特性をモニターすることにより、一定の品質の注型品を得ることができる。
【００２３】
【実施例】
本発明の一実施例を図４を用いて説明する。図４は混合条件の異なる注型樹脂主剤に硬化剤である無水フタル酸（チバガイギー社製：ＨＴ９０１）３０重量部を加えて混合後、１２０℃で硬化させた時の硬化特性を誘電計測による等価抵抗率の変化で示したものである。誘電計測には０．０１〜１００Ｈｚの周波数を用いた。樹脂が硬化すると樹脂中のイオン成分の動きが拘束され等価抵抗率の上昇として硬化の進行を検知することができる。図では主剤混合槽における混合作業を８時間行った主剤を硬化させた場合、４時間混合品に比べ反応が速くなることが示されている。つまり従来の製造方法ではこの実線の範囲内で硬化反応工程のばらつきを生じた。一方、本発明の撹拌制御により電気伝導度を３×１０^−１０Ω・ｃｍに保った主剤を用いると図中破線の硬化特性のように一定の反応性を得ることができる。
【００２４】
【発明の効果】
以上の通り本発明のエポキシ樹脂注型品の製造方法および装置によれば、エポキシ注型樹脂調整中に発生するイオン成分の濃度のコントロールが可能となり、樹脂の反応性を精密に管理することによって生産性を損なうことなく機械的、電気的欠陥の無い品質の安定したエポキシ樹脂注型品を得ることができる。特に、エポキシ樹脂注型工程において、混合方式、混合羽根形状、槽内温度分布など攪拌効率の異なる樹脂混合攪拌設備を用いても常に同じ反応性が得られるように工程管理することが可能となり、機械的、電気的欠陥の無い品質の安定したエポキシ樹脂注型品を得ることができる。
【図面の簡単な説明】
【図１】本発明のエポキシ樹脂注型品の製造装置の実施の形態の一つを表す構成図
【図２】図１の実施の形態に用いる誘電計測用のセンサーの構成図
【図３】本発明の作用を表すエポキシ注型材料主剤の電気伝導度の特性変化を示すグラフ
【図４】本発明の一実施例を表すエポキシ注型材料の硬化特性図
【符号の説明】
１…主剤混合槽
２，７…モーター
３，８…攪拌羽根
４…攪拌制御部
５，９…配管
６…ファイナルミキサー
１０…注型金型
１１…真空槽
１２…樹脂の注入口
１３…ヒーター
１４，１６…センサー
１５，１７…誘電特性検出部
１８…可使用時間判定部
１９…注型制御部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing an epoxy resin casting product such as an insulating spacer and a resin molded coil used in power equipment such as a gas circuit breaker.
[0002]
[Prior art]
Generally, in heavy electrical equipment, a metal part such as a conductor as a charging part is supported by an insulator such as an epoxy resin. In this case, the epoxy casting material comprises a main agent prepared by mixing an epoxy resin with an inorganic filler such as alumina or silica particles, and a curing agent. In the resin mixing process, after adjusting several main products for the product in a batch, stirring is continued and the next process is waited for while maintaining the dispersion of the filler and the resin temperature. After the preparation, the required amount of the main agent and curing agent are mixed and the resin is injected. For this reason, in the prior art, since a large amount of the main agent is adjusted in advance, a resin having a different mixing history of the main agent for each product has been cast.
[0003]
[Problems to be solved by the invention]
By the way, when an inorganic filler is kneaded in an epoxy resin, ionic impurities remaining in the filler purification step are eluted. The impurity ions act on the reaction as a catalyst when the resin is cured, causing variations in the reaction rate. However, in the conventional technique, since the conditions for mixing the main agent cannot be controlled, the reaction rate of the resin varies, and it is difficult to keep the quality of the cast product constant. For example, a product cast with a resin having a long main agent mixing time and a high impurity ion concentration has a fast reaction even at the same curing temperature and time, and a high reaction rate at the time of release. As a result, in products cast with such a resin, volume shrinkage in the mold increases, residual strain occurs, and mechanical defects such as cracks and electrical defects such as partial discharges may occur. is there. On the other hand, products cast with a resin having a short main agent mixing time and a low impurity ion concentration tend to cause mechanical defects in the product due to stress at the time of mold release because the reaction rate at the time of mold release decreases and the strength decreases. .
[0004]
In order to avoid the above problems, it is theoretically possible to mix and adjust the main agent for each product. However, when such a method is actually used, a mixing facility is prepared for each product, or mixing is performed. There is a possibility that a washing process is necessary for each adjustment, and the productivity is remarkably impaired.
[0005]
An object of the present invention is to provide an epoxy resin casting manufacturing method and apparatus that solves the above-described problems of the prior art, and more specifically, occurs during epoxy casting resin adjustment. An object of the present invention is to provide a method and an apparatus for producing an epoxy resin cast product in which the product quality is stabilized by controlling the concentration of ionic components and precisely controlling the reactivity of the resin.
[0006]
[Means for Solving the Problems]
The invention of claim 1 includes a step of mixing an inorganic filler with an epoxy resin and stirring to produce a main agent, a step of adding a hardener to the main agent to produce a hardener-added resin, and a step of adding this hardener-added resin. In a method for producing an epoxy resin casting product including a step of casting in a mold and a step of curing the cast resin, the dielectric characteristics of the resin are measured when the main agent is mixed, and the measurement result Based on the above, at least one of mixing time or temperature of the epoxy resin and the inorganic filler is controlled. In this case, the control of the mixing time is achieved by changing the continuous stirring operation time or intermittently performing the stirring operation.
[0007]
In the invention of claim 1 having such a configuration, it is possible to monitor the ion concentration derived from the filler that affects the reaction rate of the epoxy resin by detecting the dielectric characteristics of the main agent, and to mix the main agent and the filler. By controlling the time and temperature, the ion concentration can be maintained at a predetermined value. As a result, the reaction rate of the epoxy resin can be controlled to a desired value even when using a resin agitation equipment with different mixing method, mixing blade shape, temperature distribution in the mixing tank, etc.
The invention of claim 2 is a method for manufacturing an epoxy resin cast product including the steps as described above, wherein the dielectric properties of the curing agent-added resin are measured, and the usable time of the resin after the addition of the curing agent is determined. Features. In the invention of claim 2 having such a configuration, since the characteristics of the resin before injection can be grasped, stable material management is possible.
[0008]
According to a third aspect of the present invention, in the method for manufacturing an epoxy resin cast product including the steps as described above, at least one of the dielectric properties of the main agent or the curing agent-added resin is measured, and the measurement result is stored in the mold. It is characterized by controlling at least one of the curing time and the curing temperature of the cast resin. In the invention of claim 3 having such a configuration, even if the reactivity of the main agent or the curing agent-added resin varies, the reactivity is improved by controlling the subsequent resin curing step, thereby improving the quality of the product. Can keep.
[0009]
According to a fourth aspect of the present invention, there is provided an apparatus for manufacturing an epoxy resin cast product adopting the method as described above, wherein a main agent mixing section for mixing and stirring an inorganic filler in an epoxy resin, and an epoxy provided in the main agent mixing section. A stirrer for resin and inorganic filler, a dielectric property detector for measuring the dielectric properties of the main agent provided in the main agent mixing unit, and controlling the operation of the stirrer based on the detection value from the dielectric property detector An agitation control unit to perform,
A curing agent addition unit that adds a curing agent to the main agent supplied from the main agent mixing unit, a dielectric property detection unit that is provided in the curing agent addition unit and detects dielectric properties of the curing agent-added resin, and the dielectric property detection Usable time determination unit for determining the usable time of the curing agent-added resin based on the detection value from the part,
A mold for casting the curing agent-added resin supplied from the curing agent addition unit, a heater provided in the mold, a dielectric property detection unit of the main agent mixing unit, and a dielectric property detection unit of the curing agent addition unit And a casting control unit for setting the temperature of the heater provided in the mold and the curing time of the curing agent-added resin cast in the mold based on the detection values from these dielectric property detection units It is characterized by having.
[0010]
According to the invention of claim 4 having such a configuration, the dielectric property detection unit provided in the main agent mixing unit detects the dielectric property when the epoxy resin and the inorganic filler are mixed, and the detected value is used as the stirring control unit. To enter. The stirring control unit controls the operation time of the stirring device provided in the main agent mixing unit based on the detected value, thereby setting the ion concentration of the main agent to a predetermined value. In addition, the dielectric property detection unit of the main agent mixing unit inputs the detected value of the dielectric property of the main agent obtained by the mixing operation to the casting control unit, thereby determining the reaction rate when this main agent is cast into the mold. Judging and setting an appropriate curing time at the time of casting, an appropriate reaction temperature is set by controlling the heater and heating the mold. Similarly, by detecting the dielectric characteristics of the hardener-added resin by the dielectric characteristic detection section provided in the hardener addition section, and inputting this detection value to the casting control section, the curing time and mold during casting Control the temperature.
[0011]
In addition, the dielectric property detection unit provided in the curing agent addition unit detects the dielectric properties of the curing agent-added resin, and the detected value is input to the usable time determination unit, so that the main agent to which the curing agent is added can be used. Manage time, ie pot life.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
[0013]
(1) Configuration of Embodiment FIG. 1 is a configuration diagram showing an apparatus for manufacturing an epoxy resin cast product according to the present invention. In this embodiment, the main agent mixing section includes a casting material main agent mixing tank (premixer) 1 of an epoxy resin and an inorganic filler. The main agent mixing tank 1 is provided with a stirring blade 3 that is rotated by a motor 2 as a stirring device. The motor 2 is connected to an agitation controller 4 that sets the rotation speed, operation time, and operation interval. This main agent mixing tank 1 is connected via a pipe 5 to a final mixer 6 that constitutes a curing agent addition section. The final mixer 6 is provided with a stirring blade 8 that is rotated by a motor 7 in the same manner as the main agent mixing tank 1. The final mixer 6 is connected to a casting mold 10 via a pipe 9. The casting mold 10 is housed in a vacuum chamber 11 and includes a resin inlet 12 connected to a pipe 9 and a heater 13 that heats the mold to a predetermined temperature during a resin curing reaction. Yes.
[0014]
The main agent mixing tank 1 is provided with a sensor 14 for detecting the dielectric characteristics of the epoxy resin and the inorganic filler supplied therein. The sensor 14 is connected to a dielectric property detection unit 15 of the main agent, and the dielectric property detection unit 15 is connected to the stirring control unit 4. The final mixer 6 is also provided with a sensor 16 for dielectric measurement of the resin inside. This sensor 16 is also connected to a dielectric property detection unit 17 of a hardener-added resin, and a usable time determination unit 18 is connected to the dielectric property detection unit 17. The casting mold 10 is connected to a casting control unit 19 for setting the temperature of the heater 13 and setting the curing time of the resin in the mold. The main agent is connected to the casting control unit 19. Dielectric

characteristic detectors

15 and 17 connected to the mixing tank 1 and the final mixer 6 are connected.
[0015]
An example of the above-described sensors 14 and 16 for measuring dielectric characteristics is shown in FIG. The three types of sensors in FIG. 2 are sensors for polymer measurement. (A) is a sensor (commercially available from Micromet) provided with a comb-shaped electrode 20 on a ceramic plate 21, and (B) is a comb-shaped electrode 20 on a polyimide film 22. The provided film sensor (trade name IDEX sensor manufactured by the company), (C) is a device-mounted sensor (trade name TMS sensor manufactured by the company) in which the comb electrode 20 is supported on the ceramic 24 provided on the surface of the guard 23. These sensors have the same basic operation even if they have different external shapes, and measure the dielectric loss coefficient of the resin that has entered between the comb-shaped electrodes 20 provided in the sensor.
[0016]
(2) Operation of the embodiment The operation of the present embodiment having the above-described configuration is as follows.
[0017]
First, the epoxy resin and the inorganic filler are supplied into the main agent mixing tank 1 and mixed by driving the motor 2 and rotating the stirring blade 3. At this time, the dielectric characteristic detection unit 15 connected to the sensor 14 detects the dielectric characteristic of the resin being mixed. In general, in a dielectric material such as a polymer, the dielectric loss coefficient ε ″ is expressed by the following equation (1) from Debye's dipole theory:
[Expression 1]
ε ″ = (ε ₁ −ε _h ) ωτ / (1 + ω ² τ ² ) (1)
ε _h : unrelaxed dielectric constant (high frequency dielectric constant)
ε _l : relaxation dielectric constant (low frequency dielectric constant)
τ: Dipole relaxation time ω: Angular frequency 2πf
Further, when a conduction current flows, assuming that the electric conductivity is σ and the vacuum dielectric constant is ε ₀ , ε ″ is expressed by the following equation.
[Expression 2]

In the equation (2), when the frequency is sufficiently low and ωτ << 1, the second term can be ignored, and the following equation (3) is obtained.
[Equation 3]
ε ″ = σ / (ωε ₀ ) (3)
Therefore, the electrical conductivity σ and the equivalent resistivity ρ which is the reciprocal thereof are approximately expressed by the following equations (4) and (5).
[Expression 4]
σ = ε ″ ε ₀ ω (4)
[Equation 5]
ρ = 1 / σ = 1 / ε ″ ε ₀ ω (5)
[0018]
FIG. 3 shows a change with time in electrical conductivity during mixing of the epoxy casting resin main agent. The measurement frequency is 1 Hz and the calculation is based on equation (4). The epoxy casting resin is used as a filler for 90 parts by weight of bisferol A type epoxy resin (Ciba Geigy: CT200, epoxy equivalent 390) and 10 parts by weight of alicyclic epoxy resin (Ciba-Geigy: CY-175). 250 parts by weight of particulate alumina (manufactured by Showa Denko KK: average particle size 12 μm) was blended and vacuum mixed in the main agent mixing tank 1 at 120 ° C. During mixing, the electrical conductivity in the resin increases due to the influence of impurity ions such as alkali metals generated from the filler. If the types of ions generated are the same, the electrical conductivity is proportional to the ion concentration. In the case of conventional normal mixing, the ion concentration increases with the mixing time, and when the resin is cured, the ionic substance acts on the reaction as a catalyst, causing variations in the reaction rate.
[0019]
Therefore, in the present embodiment, the stirring conditions are controlled to such an extent that the filler is prevented from settling so that the ion concentration in the resin during mixing of the main agent is constant. That is, the output value of the sensor is determined by the dielectric property detection unit 15, and the rotation speed of the stirring blade 3 is decreased or intermittent stirring is performed by the stirring control unit 4 connected to the detection unit 15. In the present embodiment, intermittent stirring was introduced into the main agent mixing tank 1 and the dielectric properties of the resin during mixing were monitored by the sensor 14 to control the electrical conductivity to be 3 × 10 ⁻¹⁰ Ω · cm. As a result, as shown by the dotted line in FIG. 3, when the dispersion of the components is obtained by mixing the resin, the concentration of ions is kept constant by giving a gentle stirring condition that does not cause the sedimentation of the filler. be able to.
[0020]
Next, the main agent obtained as described above is sent to the final mixer 6 through the pipe 5, mixed with the curing agent there, and then into the casting mold 10 through the pipe 9 and the inlet 12. Is sent to. The casting mold 10 is provided with a casting control unit 19, and the casting control unit 10 is connected to the base material mixing tank 1 and the dielectric

property detection units

15 and 17 of the final mixer 6. The temperature of the heater 13 is set by the signals from the dielectric

characteristic detectors

15 and 17, and the reaction temperature of the resin in the casting mold 10 is controlled. The curing time is also determined by determining the ion concentration in the resin based on the signals from the

dielectric property detectors

15 and 17, and setting the curing time accordingly. As a result, even if the aging changes after mixing of the main agent or the ion concentration in the resin changes from the time of mixing of the main agent due to the stirring operation when adding the curing agent, the resin is always constant in each mold in the mold. The heater temperature can be changed to obtain a curing rate, or the curing time can be variably controlled so that the mold is always released with the same degree of curing. Moreover, even if the stirring efficiency of the various mixing stirring equipment used at each process differs, ion concentration can be managed by the instruction | command from a dielectric property detection part.
[0021]
In the present embodiment, since the usable time determination unit 18 is connected to the dielectric property detection unit 17 provided in the final mixer 6, the dielectric property of the curing agent-added resin stored in the final mixer is determined. By detecting it, the usable time can be determined. That is, when the resin to which the curing agent is added is left in the final mixer 6, the curing reaction gradually proceeds. However, when the resin is cured, the movement of the ionic component in the resin is constrained and the equivalent resistivity is increased. Can be detected.
[0022]
(3) Other Embodiments The present invention is not limited to the illustrated embodiment, and monitoring by dielectric property measurement is performed by managing the mixing conditions of the main agent and the curing agent in the final mixer and in the mold. It can be used for management of the resin curing process. In addition, even if there is a deviation in the mixing conditions of the main agent during the process and an abnormality occurs in the reactivity, it is possible to obtain a cast product of a certain quality by monitoring the dielectric characteristics of the resin inside the casting mold. .
[0023]
【Example】
An embodiment of the present invention will be described with reference to FIG. Fig. 4 shows the equivalent of the curing characteristics obtained by dielectric measurement after adding 30 parts by weight of phthalic anhydride (manufactured by Ciba Geigy Co., Ltd .: HT901) as a curing agent to the main component of the casting resin under different mixing conditions and then curing at 120 ° C. This is indicated by the change in resistivity. A frequency of 0.01 to 100 Hz was used for dielectric measurement. When the resin is cured, the movement of the ionic component in the resin is restricted, and the progress of curing can be detected as an increase in equivalent resistivity. In the figure, it is shown that when the main agent that has been mixed in the main agent mixing tank for 8 hours is cured, the reaction is faster than the mixed product for 4 hours. That is, in the conventional manufacturing method, the curing reaction process varies within the range of the solid line. On the other hand, when a main agent whose electrical conductivity is maintained at 3 × 10 ⁻¹⁰ Ω · cm by the stirring control of the present invention is used, a certain reactivity can be obtained as in the hardening characteristics indicated by the broken line in the figure.
[0024]
【The invention's effect】
As described above, according to the method and apparatus for producing an epoxy resin casting product of the present invention, it is possible to control the concentration of ionic components generated during the preparation of an epoxy casting resin, and by precisely controlling the reactivity of the resin. It is possible to obtain a stable epoxy resin cast product having no mechanical and electrical defects without impairing productivity. In particular, in the epoxy resin casting process, it becomes possible to manage the process so that the same reactivity can always be obtained even if using a resin mixing and stirring equipment with different stirring efficiency such as mixing method, mixing blade shape, temperature distribution in the tank, etc. It is possible to obtain a stable epoxy resin cast product with no mechanical and electrical defects.
[Brief description of the drawings]
FIG. 1 is a block diagram showing one embodiment of an apparatus for manufacturing an epoxy resin casting of the present invention. FIG. 2 is a block diagram of a sensor for dielectric measurement used in the embodiment of FIG. The graph which shows the characteristic change of the electrical conductivity of the epoxy casting material main ingredient showing the effect | action of this invention [FIG. 4] The hardening characteristic figure of the epoxy casting material showing one Example of this invention
DESCRIPTION OF SYMBOLS 1 ... Main agent mixing tank 2, 7 ...

Motor

3, 8 ... Stirring blade 4 ... Stirring control part 5, 9 ... Pipe 6 ... Final mixer 10 ... Casting die 11 ... Vacuum tank 12 ... Resin inlet 13 ... Heater 14 , 16 ...

Sensors

15 and 17 ... Dielectric property detection unit 18 ... Usable time determination unit 19 ... Casting control unit

Claims

A step of mixing an inorganic filler with an epoxy resin and stirring to produce a main agent, a step of adding a curing agent to the main agent to produce a curing agent-added resin, and casting the curing agent-added resin in a mold In a method for producing an epoxy resin cast product comprising a step and a step of curing the cast resin,
An epoxy resin cast product characterized by measuring the dielectric properties of the epoxy resin during the production of the main agent, and controlling at least one of the mixing time or temperature of the epoxy resin and the inorganic filler based on the measurement result. Production method.

A step of mixing an inorganic filler with an epoxy resin and stirring to produce a main agent, a step of adding a curing agent to the main agent to produce a curing agent-added resin, and casting the curing agent-added resin in a mold In a method for producing an epoxy resin cast product comprising a step and a step of curing the cast resin,
A method for producing an epoxy resin cast product, comprising measuring a dielectric property of the curing agent-added resin and determining a usable time of the resin after the curing agent is added.

A step of mixing an inorganic filler with an epoxy resin and stirring to produce a main agent, a step of adding a curing agent to the main agent to produce a curing agent-added resin, and casting the curing agent-added resin in a mold In a method for producing an epoxy resin cast product comprising a step and a step of curing the cast resin,
An epoxy resin characterized by measuring at least one dielectric property of the main agent or the cured additive resin and controlling at least one of a curing time or a curing temperature of the resin cast in the mold based on the measurement result Manufacturing method for cast products.

Mixing and stirring the inorganic filler in the epoxy resin, mixing the stirring agent for the epoxy resin and the inorganic filler provided in the mixing agent, and measuring the dielectric properties of the mixing agent provided in the mixing agent A dielectric property detection unit; and a stirring control unit that controls operation of the stirring device based on a detection value from the dielectric property detection unit;
A curing agent addition unit that adds a curing agent to the main agent supplied from the main agent mixing unit, a dielectric property detection unit that is provided in the curing agent addition unit and detects dielectric properties of the curing agent-added resin, and the dielectric property detection Usable time determination unit for determining the usable time of the curing agent-added resin based on the detection value from the part,
A mold for casting the curing agent-added resin supplied from the curing agent addition unit, a heater provided in the mold, a dielectric property detection unit of the main agent mixing unit, and a dielectric property detection unit of the curing agent addition unit And a casting control unit for setting the temperature of the heater provided in the mold and the curing time of the curing agent-added resin cast in the mold based on the detection values from these dielectric property detection units An apparatus for producing an epoxy resin cast product, comprising: