JP2012174610A - Method for manufacturing wire covered with porous ultraviolet curable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire covered with a porous ultraviolet curable resin composition having a stable outer diameter by reducing the influence of heat from a light source radiating ultraviolet light.SOLUTION: A method for manufacturing a wire covered with a porous ultraviolet curable resin composition comprises the steps of: covering an outer periphery of a metal conductor with an ultraviolet curable resin composition, in which a hydrated water absorbent polymer that is water-absorbed and swollen is distributed therein; and irradiating the ultraviolet curable resin composition covering the outer periphery of the metal conductor with ultraviolet light to cure by crosslinking of the ultraviolet curable resin composition, and also making the composition porous by dehydrating the hydrated water absorbent polymer. At a first ultraviolet light radiating furnace that irradiates the ultraviolet curable resin composition with ultraviolet light, the ultraviolet curable resin composition is irradiated with ultraviolet light in a coolant for cooling the composition to be cured by crosslinking, and after that, the hydrated water absorbent polymer is dehydrated.

Description

本発明は、金属導体の外周に多孔質の紫外線硬化型樹脂組成物被覆を施した多孔質紫外線硬化型樹脂組成物被覆電線の製造方法に関する。   The present invention relates to a method for producing a porous ultraviolet curable resin composition-coated electric wire in which a porous ultraviolet curable resin composition coating is applied to the outer periphery of a metal conductor.

近年、医療分野をはじめとする精密電子機器類や通信機器類の小型化や高密度実装化が進むなかで、これらに使用される電線・ケーブルもますます細径化が図られている。特に信号線等では、伝送信号の一層の高速化を求める傾向が顕著であり、これに使用される電線の絶縁体層を薄くかつ可能な限り低誘電率化することにより伝送信号の高速化を図ることが望まれている。   In recent years, with the progress of miniaturization and high-density mounting of precision electronic devices and communication devices such as medical fields, the diameters of electric wires and cables used for these devices have been further reduced. Especially for signal lines, etc., the tendency to further increase the speed of transmission signals is remarkable, and by increasing the transmission signal speed by reducing the dielectric constant as much as possible, the insulation layer of the wire used for this is thin. It is desired to plan.

この絶縁体層には従来、ポリエチレンやふっ素樹脂などの誘電率の低い絶縁材料を発泡（多孔質化）させたものが使われている。発泡した絶縁体層の形成は、予め発泡させたフィルムを導体上に巻き付ける方法や押出方式が知られており、特に押出方式が広く用いられている。   Conventionally, an insulating material having a low dielectric constant, such as polyethylene or fluorine resin, is foamed (porous). For forming the foamed insulator layer, a method of winding a previously foamed film on a conductor and an extrusion method are known, and the extrusion method is particularly widely used.

押出方式により発泡を形成する方法は、大きく物理的な発泡方法と化学的な発泡方法に分けられる。物理的な発泡方法としては、液体フロンのような揮発性発泡用液体を溶融樹脂中に注入し、その気化圧により発泡させる方法や窒素ガス、炭酸ガスなど押出機中の溶融樹脂に直接気泡形成用ガスを圧入させることにより一様に分布した細胞状の微細な独立気泡体を樹脂中に発生させる方法などがある。化学的な発泡方法としては、樹脂中に発泡剤を分散混合した状態で成形し、その後熱を加えることにより発泡剤の分解反応を発生させ、分解により発生するガスを利用して発泡させる方法がよく知られている。   The method of forming foam by the extrusion method is roughly divided into a physical foaming method and a chemical foaming method. As a physical foaming method, a volatile foaming liquid such as liquid chlorofluorocarbon is injected into the molten resin and foamed by its vaporization pressure, or bubbles are formed directly in the molten resin in the extruder such as nitrogen gas or carbon dioxide gas. For example, there is a method of generating fine closed cells in the form of cells uniformly distributed by injecting a working gas into the resin. As a chemical foaming method, there is a method in which a foaming agent is dispersed and mixed in a resin, then a heating agent is applied to cause a decomposition reaction of the foaming agent, and foaming is performed using a gas generated by the decomposition. well known.

押出方式に代わる薄肉被覆方式として、エナメル線に代表される熱硬化樹脂のコーティングや光ファイバの紫外線硬化樹脂のコーティングなどのコーティング方式が知られている。   As a thin coating method instead of the extrusion method, a coating method such as a coating of a thermosetting resin typified by an enameled wire or an ultraviolet curable resin coating of an optical fiber is known.

また、押出方式やコーティング方式に代わる方法として、予め水を吸収させ膨潤させた含水吸水性ポリマを液状の架橋硬化型樹脂に分散させた有機樹脂組成物を、紫外線又は熱により架橋硬化後に含水吸水性ポリマの水分を除去することにより、空孔を形成し多孔質層とする方法が提案されている（特許文献１参照）。特許文献１によれば、薄肉で細径の発泡絶縁層の形成を高速化することが容易となり、また、環境負荷も抑制することが可能となる。   As an alternative to the extrusion method or coating method, an organic resin composition in which a water-absorbing water-absorbing polymer that has been absorbed and swollen in advance is dispersed in a liquid cross-linkable curable resin is subjected to water-absorbing water absorption after being cured by UV or heat. There has been proposed a method of forming pores to form a porous layer by removing moisture from a conductive polymer (see Patent Document 1). According to Patent Document 1, it is easy to speed up the formation of a thin and thin foam insulating layer, and it is also possible to suppress environmental loads.

特開２００９−２０９１９０号公報JP 2009-209190 A

しかしながら、上記の物理的な発泡方法において、溶融樹脂中に揮発性発泡用液体を注入する方法は、気化圧が大きく気泡の微細形成が難しいため薄肉成形に限界があり、揮発性発泡用液体の注入速度が遅いため、高速成形が難しく生産性に劣るという問題がある。また、押出機中で直接気泡形成用ガスを圧入する方法は、細径薄肉化に限界があること、安全面で特別な設備や技術を必要とするため、生産性に劣ることや製造コストの上昇を招いてしまう問題がある。また、フロン、ブタン、炭酸ガス等を用いる物理的な発泡方法は
環境負荷が大きい問題がある。 However, in the physical foaming method described above, the method of injecting the volatile foaming liquid into the molten resin has a limit in thin-wall molding because the vaporization pressure is large and it is difficult to form fine bubbles. Since the injection speed is slow, there is a problem that high-speed molding is difficult and productivity is poor. In addition, the method of directly injecting the gas for forming bubbles in the extruder is limited in reducing the diameter and thickness, and requires special equipment and technology in terms of safety. There is a problem that causes an increase. In addition, a physical foaming method using chlorofluorocarbon, butane, carbon dioxide, or the like has a problem of a large environmental load.

また、上記の化学的な発泡方法においては、予め樹脂中に発泡剤を混練し、発泡剤を反応分解させて発生したガスにより発泡させるため、樹脂の成形加工温度は、発泡剤の分解温度より低く保持しなければならない問題がある。さらに、素線の径が細くなると、押出被覆では樹脂圧により断線が起こりやすく、高速化が難しくなるという別の問題もある。また、化学的な発泡方法に用いる発泡剤は価格が高いといった問題がある。   In the above chemical foaming method, the foaming agent is kneaded in advance in the resin, and the foaming agent is foamed by the gas generated by reaction decomposition of the foaming agent. Therefore, the resin molding temperature is higher than the decomposition temperature of the foaming agent. There is a problem that must be kept low. Furthermore, when the diameter of the wire becomes thin, there is another problem that the extrusion coating tends to cause disconnection due to the resin pressure, and it is difficult to increase the speed. Further, there is a problem that the foaming agent used in the chemical foaming method is expensive.

さらに、コーティング方式においては、薄肉被覆に有効な熱硬化樹脂や紫外線硬化樹脂などの液状材料を被覆させるが、熱硬化樹脂の場合、材料のかなりの部分を占める溶剤を揮散させるとともに焼付する必要がある。このため、１回のコーティングで得られる膜厚は数μｍ以下となり、多層塗りを必要とし、発泡層（多孔質層）の形成が困難である。また、撚導体では導体の隙間に溶剤が入り込み、溶剤の揮散がしにくく、被覆のふくれなどが発生しやすい。さらに溶剤を使用するため環境負荷が大きい問題がある。   Furthermore, in the coating method, a liquid material such as a thermosetting resin or an ultraviolet curable resin that is effective for thin coating is coated. However, in the case of a thermosetting resin, it is necessary to evaporate the solvent that occupies a considerable part of the material and to bake it. is there. For this reason, the film thickness obtained by one-time coating becomes several μm or less, requires multi-layer coating, and formation of a foamed layer (porous layer) is difficult. In addition, with a twisted conductor, a solvent enters the gap between the conductors, so that the solvent is not easily volatilized, and the blistering of the coating tends to occur. Furthermore, there is a problem that the environmental load is large because a solvent is used.

また、特許文献１の方法を紫外線硬化型樹脂組成物被覆電線の製造に用いた場合、紫外線硬化型樹脂組成物被覆電線の外径変動が生じやすいという問題があった。この問題を検討したところ、紫外線硬化型樹脂組成物を架橋硬化する際に用いる紫外線ランプに原因があることが明らかになった。
すなわち、紫外線ランプからは紫外線だけでなく赤外線や輻射熱が放射されるため、含水吸水性ポリマ中の水分が急激に熱せられることになる。さらに、紫外線硬化型樹脂組成物の架橋硬化にともなう反応熱（重合熱）により水分が熱せられることになる。このため、紫外線硬化型樹脂組成物が架橋硬化する前に含水吸水性ポリマ中からの水分の放出、および紫外線硬化型樹脂組成物の急激な粘性変化により、紫外線硬化型樹脂組成物被覆電線に外径変動が生じていた。 Moreover, when the method of patent document 1 was used for manufacture of an ultraviolet curable resin composition coated electric wire, there existed a problem that the outer diameter fluctuation | variation of an ultraviolet curable resin composition coated electric wire was easy to produce. Examination of this problem revealed that there is a cause in the ultraviolet lamp used when the ultraviolet curable resin composition is crosslinked and cured.
That is, since not only ultraviolet rays but also infrared rays and radiant heat are emitted from the ultraviolet lamp, the water in the water-containing water-absorbing polymer is rapidly heated. Furthermore, moisture is heated by reaction heat (polymerization heat) accompanying the crosslinking and curing of the ultraviolet curable resin composition. For this reason, before the UV curable resin composition is crosslinked and cured, the moisture is released from the water-absorbing polymer and the viscosity of the UV curable resin composition is suddenly changed. Diameter variation occurred.

本発明は、紫外線を照射する光源による熱の影響を低減して、外径の安定した多孔質紫外線硬化型樹脂組成物被覆電線が得られる多孔質紫外線硬化型樹脂組成物被覆電線の製造方法を提供することを目的とする。   The present invention relates to a method for producing a porous ultraviolet curable resin composition-coated electric wire that can reduce the influence of heat from a light source that irradiates ultraviolet rays and obtain a porous ultraviolet curable resin composition-coated electric wire having a stable outer diameter. The purpose is to provide.

本発明の第１の態様は、吸水膨潤させた含水吸水性ポリマが分散された紫外線硬化型樹脂組成物を金属導体の外周に被覆する工程と、前記金属導体の外周に被覆された前記紫外線硬化型樹脂組成物に紫外線を照射し架橋硬化させるとともに、前記含水吸水性ポリマの水分を脱水処理して多孔質化する工程と、を含む多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記紫外線硬化型樹脂組成物に紫外線を照射する１灯目の紫外線照射炉では、前記紫外線硬化型樹脂組成物を冷却する冷却液中で紫外線を照射し架橋硬化させて、その後に前記含水吸水性ポリマの水分を脱水処理する多孔質紫外線硬化型樹脂組成物被覆電線の製造方法である。   The first aspect of the present invention includes a step of coating an outer periphery of a metal conductor with an ultraviolet curable resin composition in which a water-absorbing water-absorbing polymer dispersed is absorbed, and the ultraviolet curing coated on the outer periphery of the metal conductor. In the method for producing a porous ultraviolet curable resin composition-covered electric wire, comprising irradiating the mold resin composition with ultraviolet rays and crosslinking and curing, and dehydrating the water-containing water-absorbing polymer to make it porous. In the first ultraviolet irradiation furnace for irradiating the ultraviolet curable resin composition with ultraviolet rays, the ultraviolet curable resin composition is irradiated with ultraviolet rays in a cooling liquid that cools the ultraviolet curable resin composition, followed by crosslinking and curing. This is a method for producing a porous ultraviolet curable resin composition-coated electric wire in which the moisture of the polymer is dehydrated.

上記記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記冷却液は水であることが好ましい。   In the method for producing a porous ultraviolet curable resin composition-coated electric wire as described above, the cooling liquid is preferably water.

上記記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記紫外線硬化型樹脂組成物の被覆された前記金属導体は、紫外線を照射する紫外線照射炉の、紫外線に対して透明な材料からなる透明管内に給排され又は充填されている前記冷却液中に導入されることが好ましい。   In the method for manufacturing a porous ultraviolet curable resin composition-coated electric wire as described above, the metal conductor coated with the ultraviolet curable resin composition is a material transparent to ultraviolet rays in an ultraviolet irradiation furnace for irradiating ultraviolet rays. It is preferable to introduce into the cooling liquid supplied or filled in the transparent tube made of

上記記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記透明管は前記冷却液が給排され又は充填されている内管と前記内管を囲む外管とを有する二重管構
造であって、前記外管内は乾燥ガス雰囲気または真空であることが好ましい。 In the method of manufacturing a porous ultraviolet curable resin composition-coated electric wire as described above, the transparent tube has a double tube having an inner tube in which the cooling liquid is supplied or discharged and an outer tube surrounding the inner tube. Preferably, the outer tube has a dry gas atmosphere or a vacuum.

本発明によれば、紫外線を照射する光源による熱の影響を低減して、外径の安定した多孔質紫外線硬化型樹脂組成物被覆電線を提供できる。   ADVANTAGE OF THE INVENTION According to this invention, the influence of the heat | fever by the light source which irradiates an ultraviolet-ray can be reduced, and the porous ultraviolet curable resin composition covering electric wire with which the outer diameter was stabilized can be provided.

本発明の一実施形態にかかる多孔質紫外線硬化型樹脂組成物被覆電線の製造方法で用いた製造装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the manufacturing apparatus used with the manufacturing method of the porous ultraviolet curable resin composition covering electric wire concerning one embodiment of the present invention. （ａ）は脱水処理前の紫外線硬化型樹脂組成物被覆電線の断面図であり、（ｂ）は（ａ）の脱水処理後の断面図である。(A) is sectional drawing of the ultraviolet curable resin composition covering electric wire before a dehydration process, (b) is sectional drawing after the dehydration process of (a). 図１の製造装置の紫外線照射炉を示すもので、（ａ）は冷却液が給排され又は充填される透明管を備える紫外線照射炉の一例を示す概略構成図であり、（ｂ）は（ａ）における透明管が二重管構造の紫外線照射炉の一例を示す概略構成図である。1 shows an ultraviolet irradiation furnace of the manufacturing apparatus of FIG. 1, and (a) is a schematic configuration diagram showing an example of an ultraviolet irradiation furnace including a transparent tube into which a coolant is supplied or discharged, and (b) is ( It is a schematic block diagram which shows an example of the ultraviolet irradiation furnace in which the transparent tube in a) has a double tube structure. （ａ）は実施例の多孔質紫外線硬化型樹脂組成物被覆電線の外観を示す電子顕微鏡写真であり、（ｂ）は（ａ）の電線の拡大した断面を示す電子顕微鏡写真である。(A) is an electron micrograph which shows the external appearance of the porous ultraviolet curable resin composition coating | coated electric wire of an Example, (b) is an electron micrograph which shows the expanded cross section of the electric wire of (a). 比較例における紫外線硬化型樹脂組成物被覆電線の外観を示す電子顕微鏡写真である。It is an electron micrograph which shows the external appearance of the ultraviolet curable resin composition covering electric wire in a comparative example.

上述したように、従来にあっては、紫外線ランプを用いて紫外線を照射する際に、樹脂組成物の架橋硬化と同時に、含水吸水性ポリマから水分が加熱、脱水されていた。すなわち、樹脂が十分に架橋硬化する前に脱水が生じるため、空孔の形成が阻害され、製造される電線の外径が不安定となっていた。このことから、本発明者らは紫外線を照射する光源による熱の影響を鋭意研究した。その結果、紫外線照射の１灯目において、含水吸水性ポリマ分散紫外線硬化型樹脂組成物を冷却する冷却液中で樹脂組成物の架橋硬化を行うことによって、紫外線ランプの輻射熱および紫外線硬化型樹脂組成物の反応熱（重合熱）による脱水を抑制するとともに、紫外線硬化型樹脂組成物の急激な粘性変化を抑える。これにより、架橋硬化後の脱水処理において、所定の寸法、分布を有する空孔を形成でき、電線の外径を安定化できることを見出し、本発明を創作するに至った。   As described above, conventionally, when ultraviolet rays are irradiated using an ultraviolet lamp, moisture is heated and dehydrated from the water-absorbing polymer simultaneously with the crosslinking and curing of the resin composition. That is, since dehydration occurs before the resin is sufficiently crosslinked and cured, the formation of pores is hindered, and the outer diameter of the manufactured electric wire has become unstable. From this, the present inventors diligently studied the influence of heat by the light source that irradiates ultraviolet rays. As a result, the radiation heat of the ultraviolet lamp and the ultraviolet curable resin composition are obtained by crosslinking and curing the resin composition in a cooling liquid for cooling the water-containing water-absorbing polymer-dispersed ultraviolet curable resin composition in the first lamp of ultraviolet irradiation. It suppresses dehydration due to reaction heat (polymerization heat) of the product, and suppresses a sudden viscosity change of the ultraviolet curable resin composition. As a result, in the dehydration treatment after crosslinking and curing, it has been found that pores having predetermined dimensions and distribution can be formed and the outer diameter of the electric wire can be stabilized, and the present invention has been created.

以下に、本発明にかかる多孔質紫外線硬化型樹脂組成物被覆電線を、図１に示す製造装置を用いて製造する製造方法について説明する。図１は本発明の一実施形態にかかる多孔質紫外線硬化型樹脂組成物被覆電線を製造する製造方法に用いた製造装置の一例を示す概略構成図である。図１に示すように、製造装置は、金属導体２を送り出す送出機３０と、送出機３０から送り出された金属導体２に多孔質紫外線硬化型樹脂組成物を被覆形成して巻き取る引取・巻取機３３と、の間の搬送経路には、垂直下方に電線を搬送する垂直搬送ラインを有する。この垂直搬送ラインには、上から順に、垂直下方に送られる金属導体２の外周に含水吸水性ポリマが分散された紫外線硬化型樹脂組成物を塗布する加圧塗布槽３１と、冷却液が給排される透明管を備える１段目の紫外線照射炉１０と、２段目の紫外線照射炉２１と、被覆層が硬化した電線の外径を測定する外径測定機３２と、が配置されている。さらに、上記搬送経路には、金属導体２をガイドする複数のローラ３４が配置されるとともに、引取・巻取機３３は乾燥部３５内に設置されている。   Below, the manufacturing method which manufactures the porous ultraviolet curable resin composition coating | coated electric wire concerning this invention using the manufacturing apparatus shown in FIG. 1 is demonstrated. FIG. 1 is a schematic configuration diagram showing an example of a production apparatus used in a production method for producing a porous ultraviolet curable resin composition-coated electric wire according to an embodiment of the present invention. As shown in FIG. 1, the manufacturing apparatus includes a delivery machine 30 that sends out the metal conductor 2, and a take-up / winding-up process in which the metal conductor 2 delivered from the delivery machine 30 is coated with a porous ultraviolet curable resin composition and wound. The transport path between the take-up machine 33 and the take-up machine 33 has a vertical transport line that transports the electric wires vertically downward. The vertical conveying line is supplied with a pressure application tank 31 for applying an ultraviolet curable resin composition in which a water-absorbing polymer is dispersed on the outer periphery of the metal conductor 2 that is sent vertically downward, and a coolant. A first-stage ultraviolet irradiation furnace 10 having a transparent tube to be discharged, a second-stage ultraviolet irradiation furnace 21, and an outer diameter measuring device 32 for measuring the outer diameter of the electric wire whose coating layer is cured are arranged. Yes. Further, a plurality of rollers 34 for guiding the metal conductor 2 are arranged in the transport path, and the take-up / winding machine 33 is installed in the drying unit 35.

本実施形態にかかる多孔質紫外線硬化型樹脂組成物被覆電線１の製造方法は、図１に示すように、含水吸水性ポリマが分散された紫外線硬化型樹脂組成物を金属導体２の外周に被覆する工程と、冷却液が給排される透明管を備える紫外線照射炉１０で金属導体２上の含水吸水性ポリマ分散紫外線硬化型樹脂組成物に紫外線を照射して被覆層５を形成する工程と、紫外線照射炉で被覆層５に紫外線を照射する工程と、被覆層５の含水吸水性ポリマ中の水分を脱水処理して、空孔を形成し被覆層５を多孔質化する工程と、を含む。   As shown in FIG. 1, the manufacturing method of the porous ultraviolet curable resin composition-covered electric wire 1 according to the present embodiment covers the outer periphery of the metal conductor 2 with an ultraviolet curable resin composition in which a water-absorbing water-absorbing polymer is dispersed. And a step of forming the coating layer 5 by irradiating the water-containing water-absorbing polymer-dispersed UV-curable resin composition on the metal conductor 2 with UV rays in an UV irradiation furnace 10 having a transparent tube through which coolant is supplied and discharged. A step of irradiating the coating layer 5 with ultraviolet rays in an ultraviolet irradiation furnace, and a step of dehydrating the moisture in the water-absorbing polymer of the coating layer 5 to form pores to make the coating layer 5 porous. Including.

まず、液状の紫外線硬化型樹脂組成物に、予め吸水し膨潤させた吸水性ポリマを分散させて、含水吸水性ポリマ分散紫外線硬化型樹脂組成物を準備する。
吸水性ポリマとは、非常に良く水を吸い込み、保水力が強いため多少の圧力を加えても吸水した水を放出しない高分子物質で、含水吸水性ポリマとは、吸水性ポリマに水を吸水させたものである。吸水性ポリマとしては、電気絶縁性を低下させる要因となるナトリウムを含まないものが好ましく、例えばポリアルキレンオキサイド系樹脂などがあげられる。含水吸水性ポリマは、吸水性ポリマ１ｇあたりに吸水する水の量を示す吸水量が、２０〜１００ｇ／ｇの範囲内の数値であることが好ましい。これは、吸水量が２０ｇ／ｇより少ないと、多孔質化する際の高い空隙率を得るために吸水性ポリマの添加量を多くする必要があり、コスト面や機械的特性面での問題や空孔形成効率の低下が生じやすくなるためである。一方、吸水量が１００ｇ／ｇより多いと、多孔質化する際の脱水効率が低下することや微細な空孔形成が難しくなるためである。 First, a water-absorbing polymer dispersed and swollen in advance is dispersed in a liquid UV-curable resin composition to prepare a hydrous water-absorbing polymer-dispersed UV-curable resin composition.
A water-absorbing polymer is a high-molecular substance that absorbs water very well and has a strong water-holding capacity and does not release the absorbed water even when a certain pressure is applied. A water-absorbing polymer absorbs water into the water-absorbing polymer. It has been made. The water-absorbing polymer is preferably one that does not contain sodium which causes a decrease in electrical insulation, and examples thereof include polyalkylene oxide resins. The water-absorbing water-absorbing polymer preferably has a water absorption amount indicating the amount of water absorbed per gram of water-absorbing polymer within a range of 20 to 100 g / g. If the amount of water absorption is less than 20 g / g, it is necessary to increase the amount of water-absorbing polymer in order to obtain a high porosity when making it porous. This is because the hole formation efficiency is likely to be lowered. On the other hand, if the amount of water absorption is more than 100 g / g, the dewatering efficiency at the time of making it porous is lowered and it becomes difficult to form fine pores.

また、吸水膨潤させた含水吸水性ポリマを分散させるのは、空孔のサイズや形状が、吸水性ポリマの粒子径と吸水量で制御できることや、吸水膨潤によりゲル状となった吸水性ポリマが水を多く含み、水と液状の紫外線硬化型樹脂組成物とは非相溶なので、撹拌分散の際に、独立分散しやすく、且つ球状となって分散しやすくなるからである。このため硬化後の脱水によって得られる空孔形状を球に近い形状とすることができ、つぶれに対して強いものが得られやすくなる。   In addition, the water-absorbing polymer that has been swollen with water can be dispersed because the size and shape of the pores can be controlled by the particle diameter and the amount of water absorbed by the water-absorbing polymer, This is because it contains a large amount of water and is incompatible with water and the liquid ultraviolet curable resin composition, and therefore, when stirred and dispersed, it is easily dispersed independently and becomes spherical and easily dispersed. For this reason, the hole shape obtained by dehydration after curing can be made into a shape close to a sphere, and it becomes easy to obtain a strong one against crushing.

なお、紫外線硬化型樹脂組成物としては、紫外線により硬化するもので、ウレタン系、シリコーン系、ふっ素系、エポキシ系、ポリエステル系、ポリカーボネート系など公知の樹脂組成を選択できるが、樹脂成分の誘電率が４以下であることが好ましく、３以下であるとさらに好ましい。また、紫外線硬化型樹脂組成物に添加される光重合開始剤は、使用する紫外線照射ランプの波長領域に適したものが、公知の光重合開始剤から選択される。また、金属導体２としては、銅、アルミ、ニッケルなど、またはこれらをベースとした合金があげられ、例えば、銅メッキ線た錫メッキ線などが用いられる。   The ultraviolet curable resin composition is cured by ultraviolet rays, and a known resin composition such as urethane, silicone, fluorine, epoxy, polyester or polycarbonate can be selected, but the dielectric constant of the resin component Is preferably 4 or less, and more preferably 3 or less. The photopolymerization initiator added to the ultraviolet curable resin composition is selected from known photopolymerization initiators suitable for the wavelength region of the ultraviolet irradiation lamp to be used. Further, examples of the metal conductor 2 include copper, aluminum, nickel, and alloys based on these, for example, a tin-plated wire that is a copper-plated wire.

次に、送出機３０から金属導体（撚り線）２を送り出し、ローラ３４により金属導体２をガイドして加圧塗布槽３１に送る。この加圧塗布槽３１において、塗布ダイス（図示せず）により、金属導体２の外周に、上記の含水吸水性ポリマが分散された液状の紫外線硬化型樹脂組成物を塗布して、含水吸水性ポリマ分散紫外線硬化型樹脂組成物被覆電線３（以下、被覆電線３とする）を形成する。被覆電線３は、金属導体２の外周に、含水吸水性ポリマが分散した紫外線硬化型樹脂組成物が所定の厚さで塗布されている。   Next, the metal conductor (stranded wire) 2 is sent out from the feeder 30, and the metal conductor 2 is guided by the roller 34 and sent to the pressure application tank 31. In this pressure application tank 31, a liquid ultraviolet curable resin composition in which the above water-absorbing water-absorbing polymer is dispersed is applied to the outer periphery of the metal conductor 2 by a coating die (not shown). A polymer-dispersed ultraviolet curable resin composition-coated wire 3 (hereinafter referred to as a coated wire 3) is formed. In the coated electric wire 3, an ultraviolet curable resin composition in which a water-containing water-absorbing polymer is dispersed is applied to the outer periphery of the metal conductor 2 with a predetermined thickness.

次に、図１、図２（ａ）に示すように、冷却液としての水が給排され、紫外線に対して透明な材料からなる透明管としての石英管を備える紫外線照射炉１０に被覆電線３を送り、水中で金属導体２の外周の紫外線硬化型樹脂組成物６に紫外線を照射し、紫外線硬化型樹脂組成物６が架橋硬化され被覆層５の形成された、硬化した含水吸水性ポリマ分散紫外線硬化型樹脂組成物被覆電線４（以下、硬化した被覆電線４とする）を形成する。この被覆層５は、金属導体２の外周に形成され、硬化した紫外線硬化型樹脂組成物６中に含水吸水性ポリマ７が分散した構造となっている。   Next, as shown in FIG. 1 and FIG. 2 (a), water as a coolant is supplied and discharged, and an ultraviolet irradiation furnace 10 having a quartz tube as a transparent tube made of a material transparent to ultraviolet rays is covered with a covered electric wire. The cured water-containing water-absorbing polymer in which the ultraviolet curable resin composition 6 on the outer periphery of the metal conductor 2 is irradiated with ultraviolet rays in water, and the ultraviolet curable resin composition 6 is crosslinked and cured to form the coating layer 5. A dispersed ultraviolet curable resin composition-coated wire 4 (hereinafter referred to as a cured coated wire 4) is formed. The coating layer 5 is formed on the outer periphery of the metal conductor 2 and has a structure in which the water-absorbing polymer 7 is dispersed in the cured ultraviolet curable resin composition 6.

水が給排される石英管を備える紫外線照射炉１０（以下、紫外線照射炉１０とする）は、図３（ａ）に示すように、炉内には紫外線を照射する紫外線ランプ１１が設けられるとともに、被覆電線３が垂直に通過する石英管１２が設置されている。また、紫外線照射炉１０の内壁面部には、赤外線を透過させ紫外線を反射する反射鏡としてのコールドミラー（図示せず）を備えている。紫外線ランプ１１は紫外線を発光し、石英管１２内を通過する金属導体２外周の紫外線硬化型樹脂組成物６を架橋硬化するが、紫外線ランプ１１とし
て、高圧水銀ランプやメタルハライドランプなどの放電ランプなどが用いられる場合、発光する光には紫外線以外に赤外線が含まれることになる。また、紫外線ランプ１１は発光に伴って発熱して、紫外線照射炉１０内の温度を上昇させる。
本実施形態において、石英管１２は、水Ｗを供給する供給口１４を下部に、水Ｗを排出する排出口１５を上部にそれぞれ備えている。石英管１２は、水Ｗが供給口１４から供給されるとともに排出口１５から排出されて、石英管１２内の水Ｗ中を通過する被覆電線３を冷却して、紫外線ランプ１１からの赤外線照射による熱の影響を低減している。
すなわち、水Ｗが給排される石英管１２内の被覆電線３に紫外線ランプ１１で照射する際に、紫外線ランプ１１から照射される紫外線に含まれる赤外線による輻射熱を水Ｗで冷却することができる。また、被覆電線３を水Ｗ中に導入することにより架橋硬化にともなう反応熱（重合熱）も冷却できるとともに、紫外線ランプ１１の発光にともなう紫外線照射炉１０内の温度上昇から被覆電線３を保護することが可能となる。さらに、被覆電線３の発熱を低減して、樹脂中に含まれる低分子量成分の揮発を抑制できるので、揮発成分の石英管１２への付着、および付着にともなう紫外線の透過率の低下を抑制することができる。
このように、紫外線照射の一段目（１灯目）の紫外線照射炉１０において、水Ｗ中で紫外線を照射することにより、輻射熱および重合熱による紫外線硬化型樹脂組成物６の温度上昇を抑制するとともに、発光に伴い上昇する紫外線照射炉１０の炉内温度から被覆電線３を保護しつつ架橋硬化させることができる。
したがって、紫外線硬化型樹脂組成物６の硬化過程（硬化が不十分な状態）において、含水吸水性ポリマ７中の水分の加熱による放出、および紫外線硬化型樹脂組成物６の急激な粘性変化を抑制でき、空孔形成の阻害および樹脂組成物被覆電線の外径変動を抑制することができる。 As shown in FIG. 3A, an ultraviolet irradiation furnace 10 (hereinafter referred to as an ultraviolet irradiation furnace 10) having a quartz tube through which water is supplied and discharged is provided with an ultraviolet lamp 11 for irradiating ultraviolet rays. In addition, a quartz tube 12 through which the covered electric wire 3 passes vertically is installed. The inner wall surface of the ultraviolet irradiation furnace 10 is provided with a cold mirror (not shown) as a reflecting mirror that transmits infrared rays and reflects ultraviolet rays. The ultraviolet lamp 11 emits ultraviolet rays and crosslinks and cures the ultraviolet curable resin composition 6 on the outer periphery of the metal conductor 2 that passes through the quartz tube 12. As the ultraviolet lamp 11, a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp is used. Is used, the emitted light contains infrared rays in addition to ultraviolet rays. Further, the ultraviolet lamp 11 generates heat with light emission and raises the temperature in the ultraviolet irradiation furnace 10.
In the present embodiment, the quartz tube 12 includes a supply port 14 for supplying water W at the lower portion and an outlet 15 for discharging water W at the upper portion. The quartz tube 12 is supplied with water W from the supply port 14 and is discharged from the discharge port 15 to cool the covered electric wire 3 passing through the water W in the quartz tube 12 and irradiate infrared rays from the ultraviolet lamp 11. The effect of heat due to is reduced.
That is, when the coated wire 3 in the quartz tube 12 to which the water W is supplied and discharged is irradiated with the ultraviolet lamp 11, the radiant heat generated by the infrared rays contained in the ultraviolet light irradiated from the ultraviolet lamp 11 can be cooled by the water W. . Further, by introducing the covered electric wire 3 into the water W, the reaction heat (polymerization heat) accompanying the crosslinking and curing can be cooled, and the covered electric wire 3 is protected from the temperature rise in the ultraviolet irradiation furnace 10 caused by the light emission of the ultraviolet lamp 11. It becomes possible to do. Furthermore, since the heat generation of the covered electric wire 3 can be reduced and volatilization of the low molecular weight component contained in the resin can be suppressed, the adhesion of the volatile component to the quartz tube 12 and the decrease in the transmittance of ultraviolet rays accompanying the adhesion are suppressed. be able to.
In this way, in the ultraviolet irradiation furnace 10 in the first stage (first lamp) of ultraviolet irradiation, the temperature rise of the ultraviolet curable resin composition 6 due to radiant heat and polymerization heat is suppressed by irradiating ultraviolet light in water W. At the same time, it is possible to crosslink and cure the coated electric wire 3 while protecting the covered electric wire 3 from the temperature inside the ultraviolet irradiation furnace 10 that rises with light emission.
Therefore, in the curing process of the ultraviolet curable resin composition 6 (in a state where the curing is insufficient), the release of moisture in the water-containing water-absorbing polymer 7 and the sudden viscosity change of the ultraviolet curable resin composition 6 are suppressed. It is possible to inhibit hole formation and fluctuation of the outer diameter of the resin composition-covered electric wire.

上記実施形態において、冷却液として水を用いたが、冷却液は、紫外線の吸収が少なく、かつ含水吸水性ポリマ中の水分を脱水しないものであれば、水に限らない。水は、赤外線を一部吸収するため、赤外線による輻射熱を低減し金属導体２などの温度上昇を抑制することができる。さらに、被覆電線３を水環境下に導入することで、含水吸水性ポリマ中の水分量を低減することなく一定とすることが可能となる。   In the above embodiment, water is used as the cooling liquid. However, the cooling liquid is not limited to water as long as it absorbs less ultraviolet light and does not dehydrate the water in the water-absorbing polymer. Since water partially absorbs infrared rays, it is possible to reduce radiant heat due to infrared rays and suppress temperature rise of the metal conductor 2 and the like. Furthermore, by introducing the covered electric wire 3 into a water environment, it becomes possible to make the water content in the water-containing water-absorbing polymer constant without reducing it.

上記実施形態において、透明管として石英管を用いたが、透明管の材料には、紫外線に対して透明であれば石英に限定されず、紫外線透過率の高い石英以外のガラスや樹脂などを用いることができる。石英管は耐熱性が高く紫外線の透過率が高いため透明管に好適である。
また、透明管は、冷却液が給排される内管と内管を囲む外管とを有する二重管構造の石英管であって、外管内は乾燥ガス雰囲気または真空とすることが好ましい。二重管構造石英管１６とは、図３（ｂ）に示すように、供給口１４および排出口１５を有し、水Ｗが給排される内管１７と、ガス供給口１９およびガス排出口２０を有し、乾燥ガス雰囲気にある外管１８と、を備える構造を示す。乾燥ガス雰囲気とは、乾燥ガスＧが給排又は充填され、雰囲気中に含まれる水分（水蒸気）が少ない又は実質的にない状態をいう。
図３（ａ）に示すような石英管１２の表面においては、水Ｗが給排される石英管１２の内部とその外部とでは温度差が大きいため、石英管１２の表面に結露が生じ、その結露により透明管１２の表面における紫外線の透過率が低下することになる。一方、透明管を二重管構造石英管１６とすることによって、内管１７を覆う外管１８中の水分（水蒸気）を減少し結露の発生を抑制することができる。しかも、外管１８を設けて断熱効果を得ることにより給排される水Ｗの温度上昇を抑えることができる。なお、用いる乾燥ガスとしては、水蒸気を含有しないものであればよく、取り扱い性などの観点から乾燥空気が好ましい。また、外管１８内を真空状態として、結露の発生を防止しても良い。 In the above embodiment, the quartz tube is used as the transparent tube. However, the material of the transparent tube is not limited to quartz as long as it is transparent to ultraviolet rays, and glass or resin other than quartz having high ultraviolet transmittance is used. be able to. A quartz tube is suitable for a transparent tube because of its high heat resistance and high ultraviolet transmittance.
The transparent tube is a quartz tube having a double tube structure having an inner tube through which coolant is supplied and discharged and an outer tube surrounding the inner tube, and the outer tube is preferably a dry gas atmosphere or a vacuum. As shown in FIG. 3B, the double-pipe structure quartz tube 16 has a supply port 14 and a discharge port 15, an inner tube 17 through which water W is supplied and discharged, a gas supply port 19 and a gas discharge port. A structure having an outlet 20 and an outer tube 18 in a dry gas atmosphere is shown. The dry gas atmosphere refers to a state in which the dry gas G is supplied or discharged or filled, and moisture (water vapor) contained in the atmosphere is little or substantially absent.
On the surface of the quartz tube 12 as shown in FIG. 3A, since there is a large temperature difference between the inside and outside of the quartz tube 12 through which water W is supplied and discharged, dew condensation occurs on the surface of the quartz tube 12, Due to the condensation, the transmittance of ultraviolet rays on the surface of the transparent tube 12 is lowered. On the other hand, by making the transparent tube a double tube structure quartz tube 16, moisture (water vapor) in the outer tube 18 covering the inner tube 17 can be reduced and the occurrence of condensation can be suppressed. And the temperature rise of the water W supplied / exhausted can be suppressed by providing the outer tube | pipe 18 and obtaining the heat insulation effect. In addition, as dry gas to be used, what does not contain water vapor | steam should just be used, and dry air is preferable from viewpoints, such as handleability. Further, the inside of the outer tube 18 may be evacuated to prevent the occurrence of condensation.

続いて、被覆層５が形成され、硬化した被覆電線４を、紫外線照射炉２１に送り紫外線
を照射して、被覆層５をさらに十分に架橋硬化する。紫外線照射炉２１は、図示しないが、上述した紫外線照射炉１０と同様に、紫外線ランプ、石英管、コールドミラーを備えており、紫外線照射炉１０とは、冷却液としての水が石英管内に給排されない点だけが異なる。
本実施形態においては、被覆層５に紫外線をさらに照射するに際して、冷却液としての水を用いずに大気中で紫外線を照射している。紫外線ランプを用いることにより含水吸水性ポリマの水分が加熱されるが、上述した一段目の冷却液としての水が給排される石英管を備える紫外線照射炉１０において、被覆電線３は外径変動が生じない程度に架橋硬化された被覆層５が形成されるので、外径の変動は生じにくい。しかも、２段目の紫外線照射炉２１において、紫外線ランプにより被覆層５の架橋硬化に加えて脱水処理も同時になされ、後述する脱水工程において、脱水処理時間の短縮や脱水処理装置の縮小などが可能となる。 Subsequently, the coated electric wire 4 on which the coating layer 5 is formed and cured is sent to the ultraviolet irradiation furnace 21 and irradiated with ultraviolet rays, so that the coating layer 5 is further sufficiently crosslinked and cured. Although not shown, the ultraviolet irradiation furnace 21 includes an ultraviolet lamp, a quartz tube, and a cold mirror, similar to the ultraviolet irradiation furnace 10 described above. The ultraviolet irradiation furnace 10 supplies water as a coolant into the quartz tube. The only difference is that it is not eliminated.
In the present embodiment, when the coating layer 5 is further irradiated with ultraviolet rays, the ultraviolet rays are irradiated in the atmosphere without using water as a coolant. The moisture of the water-absorbing water-absorbing polymer is heated by using the ultraviolet lamp. In the ultraviolet irradiation furnace 10 provided with the quartz tube through which the water as the first-stage cooling liquid is supplied and discharged, the coated wire 3 has an outer diameter variation. Since the coating layer 5 that is cross-linked and cured to such an extent that no occurrence occurs, fluctuations in the outer diameter are unlikely to occur. In addition, in the ultraviolet irradiation furnace 21 in the second stage, the dehydration process is simultaneously performed in addition to the cross-linking and curing of the coating layer 5 by the ultraviolet lamp. In the dehydration process described later, the dehydration process time can be shortened and the dehydration apparatus can be reduced. It becomes.

続いて、図１に示すように、硬化した被覆電線４は外径測定機３２を通過することにより、その外径が連続的に測定され、搬送速度の制御などに利用される。外径測定機３２としては非接触のレーザ方式などが用いられる。   Subsequently, as shown in FIG. 1, the cured covered electric wire 4 passes through the outer diameter measuring device 32, so that the outer diameter is continuously measured and used for controlling the conveyance speed and the like. A non-contact laser system or the like is used as the outer diameter measuring device 32.

続いて、被覆層５が形成され、硬化した被覆電線４は、乾燥部３５内の引取・巻取機３３へと巻き取られる。乾燥部３５は、図１に示すように、硬化した被覆電線４の搬送距離を長くして乾燥時間を長くするために、硬化した被覆電線４を反転などするための複数のローラ３４が配置される。この乾燥部３５において、硬化した被覆電線４の搬送中（あるいは更に引取・巻取機３３に巻き取った硬化した被覆電線４を放置することにより）、被覆層５中に分散した含水吸水性ポリマ７の水分を自然乾燥し脱水する。この乾燥による脱水処理で、含水吸水性ポリマ７中の水分が脱水、除去され、図２（ｂ）に示すような空孔８が形成され、被覆層５が多孔質化された多孔質紫外線硬化型樹脂組成物被覆電線１が形成される。
上記実施形態においては、脱水処理を自然乾燥により行ったが、乾燥部内を高温に保持し乾燥による脱水処理を促進するようにしてもよい。また、マイクロ波により加熱して脱水することも可能である。マイクロ波による加熱によれば水分を急速に加熱できるので、吸水性ポリマや周囲の樹脂などに影響をあたえることなく、短時間で効率よく空孔を形成できる。また、電線を搬送する距離を低減することができるので、装置を小型化・縮小化することができる。 Subsequently, the coating layer 5 is formed, and the cured coated electric wire 4 is wound around the take-up / winding machine 33 in the drying unit 35. As shown in FIG. 1, the drying unit 35 is provided with a plurality of rollers 34 for inverting the cured coated electric wire 4 in order to increase the transport distance of the cured coated electric wire 4 and increase the drying time. The In this drying unit 35, the water-containing water-absorbing polymer dispersed in the coating layer 5 during conveyance of the cured coated electric wire 4 (or by leaving the cured coated electric wire 4 wound around the take-up / winding machine 33 left). 7 water is dried naturally and dehydrated. By this dehydration treatment by drying, moisture in the water-containing water-absorbing polymer 7 is dehydrated and removed to form pores 8 as shown in FIG. 2 (b), and the coating layer 5 is made porous. A molded resin composition-covered electric wire 1 is formed.
In the above embodiment, the dehydration process is performed by natural drying. However, the inside of the drying unit may be maintained at a high temperature to accelerate the dehydration process by drying. It is also possible to dehydrate by heating with microwaves. By heating with microwaves, moisture can be rapidly heated, so that pores can be efficiently formed in a short time without affecting the water-absorbing polymer or the surrounding resin. Moreover, since the distance which conveys an electric wire can be reduced, an apparatus can be reduced in size and reduced.

上述したように、本実施形態においては、金属導体の外周に塗布された、含水吸水性ポリマを分散した紫外線硬化型樹脂組成物に紫外線を照射する１灯目において、水中（冷却液中）で紫外線を照射する。この構成により、輻射熱および重合熱による金属導体などの温度上昇を抑制するとともに、紫外線ランプの発光による紫外線照射炉内の温度上昇から含水吸水性ポリマ分散紫外線硬化型樹脂組成物被覆電線を保護するため、含水吸水性ポリマ分散紫外線硬化型樹脂組成物の硬化過程（架橋硬化が不十分な状態）において、含水吸水性ポリマからの水分の加熱、脱水を最小限に抑制することができる。そして、含水吸水性ポリマ分散紫外線硬化型樹脂組成物の硬化前における急速な粘性や流動性変化による空孔の形成の阻害を抑制し、被覆樹脂の塗りムラがなく外径の安定した多孔質紫外線硬化型樹脂組成物被覆電線を形成することができる。また、被覆樹脂を多孔質化して誘電率を低下することができるので、細径、薄肉化した伝送速度の高い信号線などを形成することができる。   As described above, in the present embodiment, in the first lamp for irradiating ultraviolet rays to the ultraviolet curable resin composition dispersed with the water-absorbing water-absorbing polymer applied to the outer periphery of the metal conductor, in water (in the coolant) Irradiate ultraviolet rays. This structure suppresses the temperature rise of the metal conductor due to radiant heat and polymerization heat, and protects the water-absorbing polymer-dispersed UV-curable resin composition-covered wire from the temperature rise in the UV irradiation furnace caused by the UV lamp emission. In the curing process of the water-absorbing water-absorbing polymer-dispersed ultraviolet curable resin composition (in a state where crosslinking curing is insufficient), heating and dehydration of water from the water-absorbing water-absorbing polymer can be suppressed to a minimum. In addition, porous ultraviolet light with stable outer diameter without coating unevenness of coating resin is suppressed by inhibiting the formation of pores due to rapid viscosity and fluidity change before curing of water-absorbing polymer-dispersed UV curable resin composition A curable resin composition-coated electric wire can be formed. In addition, since the dielectric constant can be lowered by making the coating resin porous, it is possible to form a signal line having a small diameter and a small thickness and a high transmission speed.

なお、上記実施形態では水（冷却液）が給排される場合について説明したが、本発明はこれに限定されない。例えば、冷却液を循環させたり、あるいは透明管内に冷却液を流さずに充填させた状態のままとしてもよい。また、上記実施形態では、二段（２灯）ある紫外線照射炉の一段目において冷却液中で紫外線を照射し、二段目において冷却液を用いず
に紫外線を照射した場合について説明したが、本発明はこれに限定されない。紫外線照射工程の１灯目において、冷却液中で紫外線照射を行えばよく、例えば、二段以上の冷却液中での紫外線照射、または冷却液中での紫外線照射と冷却液を用いない紫外線照射を組み合わせた三段以上の紫外線照射としてもよい。 In addition, although the said embodiment demonstrated the case where water (coolant) was supplied / discharged, this invention is not limited to this. For example, the coolant may be circulated, or the transparent tube may be filled without flowing the coolant. Further, in the above embodiment, the case where the ultraviolet ray is irradiated in the cooling liquid in the first stage of the two-stage (two lamps) ultraviolet irradiation furnace and the ultraviolet ray is irradiated without using the cooling liquid in the second stage, The present invention is not limited to this. In the first lamp of the UV irradiation process, UV irradiation may be performed in a cooling liquid, for example, UV irradiation in two or more stages of cooling liquid, or UV irradiation in a cooling liquid and UV irradiation without using a cooling liquid. It is good also as ultraviolet irradiation of 3 steps | paragraphs or more which combined these.

また、上記実施形態において、紫外線照射炉に備える紫外線ランプは、特に限定されず、放電ランプやＬＥＤランプなどを好適に用いることが可能である。   Moreover, in the said embodiment, the ultraviolet lamp with which an ultraviolet irradiation furnace is equipped is not specifically limited, A discharge lamp, an LED lamp, etc. can be used suitably.

また、本発明の金属導体は、複数の金属導体を撚りあわせた撚り線に限らず、単線の金属導体の電線にも適用可能である。また、本発明は、電線に限定されず、多孔質紫外線硬化型樹脂組成物被覆電線の外周に、さらに金属導体およびシースを設けた同軸ケーブルや、複数の多孔質紫外線硬化型樹脂組成物被覆電線を用い、これら電線などを平行に束ねたりして、その外周にシースを設けたケーブルなどにも適用できる。   Moreover, the metal conductor of this invention is applicable not only to the strand wire which twisted the some metal conductor but to the electric wire of a single wire metal conductor. Further, the present invention is not limited to electric wires, and a coaxial cable in which a metal conductor and a sheath are further provided on the outer periphery of a porous ultraviolet curable resin composition-coated electric wire, and a plurality of porous ultraviolet curable resin composition-coated electric wires Can be applied to a cable or the like in which these electric wires are bundled in parallel and a sheath is provided on the outer periphery thereof.

次に、本発明の実施例を説明する。   Next, examples of the present invention will be described.

まず、本発明の実施例において用いる含水吸水性ポリマ含有の紫外線硬化型樹脂組成物について説明する。
紫外線硬化型樹脂組成物には、オリゴマー成分として、Ｈ−ＭＤＩ変性ポリエチレングリコールアジペートジメタクリレートオリゴマ（UA-4002HM、新中村化学）を１００重量
部、モノマー成分として、シクロペンタニルアクリレート（FA-513AS、日立化成工業）を５５重量部、光重合開始剤として１-ヒドロキシシクロヘキシルフェニルケトン（IRGACURE 184、チバスペシャリテイケミカルズ）を３重量部、および２，４，６−トリメチルベ
ンゾイルジフェニルフォスフィンオキサイド（DAROCUR TPO、チバスペシャリテイケミカ
ルズ）を４．５重量部、酸化防止剤として２，２−チオジエチレンビス［３−（３，５−ジ−t−ブチル−４−ヒドロキシフェニル）プロピオネート］（IRGANOX1035、チバスペシャリテイケミカルズ）を０．１５重量部、安定剤としてヒドロキノンを０．１５重量部、を添加して混練機により混練した、紫外線硬化型樹脂組成物Ａを使用した。 First, the ultraviolet curable resin composition containing a water-absorbing polymer used in the examples of the present invention will be described.
In the ultraviolet curable resin composition, 100 parts by weight of H-MDI-modified polyethylene glycol adipate dimethacrylate oligomer (UA-4002HM, Shin-Nakamura Chemical) as an oligomer component, and cyclopentanyl acrylate (FA-513AS, 55 parts by weight of Hitachi Chemical Co., Ltd., 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184, Ciba Specialty Chemicals) as a photopolymerization initiator, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (DAROCUR TPO) , Ciba Specialty Chemicals), 2,2-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (IRGANOX1035, Ciba Specialty) 0.15 parts by weight of chemicals) 0.15 parts by weight of hydroquinone were kneaded by a kneader was added to using an ultraviolet-curable resin composition A.

紫外線硬化型樹脂組成物Ａに分散させる含水吸水性ポリマは、平均粒径５０μｍの吸水性ポリマ（アクアコークＴＷＰ−ＰＦ 住友精化製）と蒸留水とを１：３１の比率で混ぜ合わせ２４時間静置した後、高圧ホモジナイザー（PANDA 2K型 Niro Soavi社製）を用い
圧力１３０ＭＰａで、１回処理した含水吸水性ポリマＢを使用した。 The water-absorbing water-absorbing polymer dispersed in the ultraviolet curable resin composition A is obtained by mixing a water-absorbing polymer having an average particle diameter of 50 μm (Aqua Coke TWP-PF, manufactured by Sumitomo Seika) at a ratio of 1:31 for 24 hours. After standing still, a water-absorbing polymer B treated once using a high-pressure homogenizer (PANDA 2K type, manufactured by Niro Soavi) at a pressure of 130 MPa was used.

上記紫外線硬化型樹脂組成物Ａに、含水率が６０％となるように含水吸水性ポリマＢを添加して、５０℃に加温しながら３０分、回転数６００ｒｐｍで攪拌分散し、含水吸水性ポリマ分散紫外線硬化型樹脂組成物Ｃを準備した。   A water-absorbing polymer B was added to the ultraviolet curable resin composition A so that the water content was 60%, and the mixture was stirred and dispersed at 600 rpm for 30 minutes while heating to 50 ° C. A polymer-dispersed ultraviolet curable resin composition C was prepared.

（実施例１）
金属導体として、４０ＡＷＧ（素線本数７、素線直径０．０３ｍｍ）の銀メッキ銅撚り線の外周に、加圧塗布槽を用いて、４０℃に加温した含水吸水性ポリマ分散紫外線硬化型樹脂組成物Ｃを速度１００ｍ／ｍｉｎで被覆（厚さ１１０μｍ）した。そして、含水吸水性ポリマ分散紫外線硬化型樹脂組成物Ｃに被覆された撚り線を、一段目の紫外線照射炉として、二重管構造の石英管を備え、内管の中に水を循環させ、外管に乾燥空気を給排させた紫外線照射炉（メタルハライドランプ:アイグラフィックス製、６ｋＷ、ランプ長２５
０ｍｍ、波長２３０〜６００ｎｍ）に通して、紫外線硬化型樹脂組成物を架橋硬化して被覆層を形成した。さらに、二段目の紫外線照射炉として、通常の石英管を備えた紫外線照射炉（メタルハライドランプ:アイグラフィックス製、６ｋＷ、ランプ長２５０ｍｍ、波
長２３０〜６００ｎｍ）に通して、さらに架橋硬化して、被覆厚が約１１０μｍの被覆層
を形成した。硬化された被覆層は、その後乾燥、もしくはマイクロ波などにより加熱され、被覆層中の含水吸水性ポリマの水分を除去して空孔を形成することにより、多孔質紫外線硬化型樹脂組成物被覆電線を得た。 Example 1
As a metal conductor, a water-absorbing polymer-dispersed UV curable type heated to 40 ° C. on the outer periphery of a silver-plated copper stranded wire of 40 AWG (7 strands, strand diameter 0.03 mm) using a pressure coating tank Resin composition C was coated (thickness: 110 μm) at a speed of 100 m / min. The stranded wire coated with the water-absorbing polymer-dispersed UV curable resin composition C is used as a first stage UV irradiation furnace, equipped with a double-pipe quartz tube, and water is circulated in the inner tube. Ultraviolet irradiation furnace (metal halide lamp: made by iGraphics, 6 kW, lamp length 25)
0 mm, wavelength 230 to 600 nm), and the ultraviolet curable resin composition was crosslinked and cured to form a coating layer. Furthermore, as a second stage ultraviolet irradiation furnace, it was passed through an ultraviolet irradiation furnace (metal halide lamp: made by iGraphics, 6 kW, lamp length 250 mm, wavelength 230 to 600 nm) equipped with a normal quartz tube, and further crosslinked and cured. A coating layer having a coating thickness of about 110 μm was formed. The cured coating layer is then dried or heated by microwaves or the like to remove moisture from the water-absorbing polymer in the coating layer to form pores, thereby forming a porous ultraviolet curable resin composition-coated electric wire. Got.

上記で得られた多孔質紫外線硬化型樹脂組成物被覆電線を、電子顕微鏡を用いて観察した。その結果、図４（ａ）に示すように、電線の外径は安定しており、その外径変動は±１０μｍ以下となっていた。また、図４（ｂ）に示すように、空孔は潰されることなく被覆層中に分散されて形成されていた。なお、外径変動の許容範囲は被覆層の厚さにより変化して、被覆層の厚さが１１０μｍの場合は±２０μｍ以下であれば実用上問題はない。   The porous ultraviolet curable resin composition-covered electric wire obtained above was observed using an electron microscope. As a result, as shown in FIG. 4A, the outer diameter of the electric wire was stable, and the outer diameter fluctuation was ± 10 μm or less. Moreover, as shown in FIG.4 (b), the void | hole was dispersed and formed in the coating layer, without being crushed. The permissible range of fluctuations in the outer diameter varies depending on the thickness of the coating layer. When the thickness of the coating layer is 110 μm, there is no practical problem as long as it is ± 20 μm or less.

（比較例１）
比較例１では、紫外線照射の一段目および二段目のそれぞれにおいて、通常の石英管を装着した紫外線照射炉（メタルハライドランプ:アイグラフィックス製、６ｋＷ、ランプ
長２５０ｍｍ、波長２３０〜６００ｎｍ）を用いて、大気中で紫外線を照射した点が実施例１と異なるだけで、その他の構成については実施例１と同じである。 (Comparative Example 1)
In Comparative Example 1, an ultraviolet irradiation furnace (metal halide lamp: made by Eye Graphics, 6 kW, lamp length 250 mm, wavelength 230 to 600 nm) equipped with a normal quartz tube was used in each of the first and second stages of ultraviolet irradiation. The other points are the same as those of the first embodiment except that the ultraviolet rays are irradiated in the atmosphere.

実施例１と同様に、電子顕微鏡により観察した結果、図５に示すように、電線の外径が不安定となり、空孔の潰れや金属導体の露出が観察された。また、電線の外径変動は±５０μｍ以上となっており、実用上問題が生じる。   As in Example 1, as a result of observation with an electron microscope, as shown in FIG. 5, the outer diameter of the electric wire became unstable, and collapse of the holes and exposure of the metal conductor were observed. Further, the outer diameter fluctuation of the electric wire is ± 50 μm or more, which causes a practical problem.

実施例及び比較例から明らかなように、含水吸水性ポリマを分散させた紫外線硬化型樹脂組成物を金属導体上に被覆して架橋硬化させる際に、少なくとも紫外線照射の１灯目において、冷却液中で紫外線を照射して架橋硬化することで安定した外径の多孔質紫外線硬化型樹脂組成物被覆電線を得られることがわかった。   As is clear from the examples and comparative examples, when the ultraviolet curable resin composition in which the water-containing water-absorbing polymer is dispersed is coated on the metal conductor and crosslinked and cured, at least in the first lamp irradiated with ultraviolet rays, It was found that a porous ultraviolet curable resin composition-coated electric wire having a stable outer diameter can be obtained by irradiating ultraviolet rays therein and curing by crosslinking.

１ 多孔質紫外線硬化型樹脂組成物被覆電線
２ 金属導体
３ 含水吸水性ポリマ分散紫外線硬化型樹脂組成物被覆電線
４ 硬化した含水吸水性ポリマ分散紫外線硬化型樹脂組成物被覆電線
５ 被覆層
６ 紫外線硬化型樹脂組成物
７ 含水吸水性ポリマ
８ 空孔
１０ 水が給排される石英管を備える紫外線照射炉
１１ 紫外線ランプ
１２ 石英管（透明管）
１６ 二重管構造石英管
１７ 内管
１８ 外管
２１ 紫外線照射炉
３１ 加圧塗布槽
３５ 乾燥部
Ｗ 水（冷却液）
Ｇ 乾燥ガス DESCRIPTION OF SYMBOLS 1 Porous ultraviolet curable resin composition coated electric wire 2 Metal conductor 3 Water-containing water-absorbing polymer-dispersed UV-curable resin composition-coated electric wire 4 Cured water-absorbing polymer-dispersed UV-curable resin composition-coated electric wire 5 Coating layer 6 Ultraviolet curing Mold resin composition 7 Water-containing water-absorbing polymer 8 Hole 10 Ultraviolet irradiation furnace 11 equipped with quartz tube through which water is supplied and discharged Ultraviolet lamp 12 Quartz tube (transparent tube)
16 Double tube structure quartz tube 17 Inner tube 18 Outer tube 21 Ultraviolet irradiation furnace 31 Pressure coating tank 35 Drying section W Water (coolant)
G Dry gas

Claims (4)

吸水膨潤させた含水吸水性ポリマが分散された紫外線硬化型樹脂組成物を金属導体の外周に被覆する工程と、
前記金属導体の外周に被覆された前記紫外線硬化型樹脂組成物に紫外線を照射し架橋硬化させるとともに、前記含水吸水性ポリマの水分を脱水処理して多孔質化する工程と、を含む多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、
前記紫外線硬化型樹脂組成物に紫外線を照射する１灯目の紫外線照射炉では、前記紫外線硬化型樹脂組成物を冷却する冷却液中で紫外線を照射し架橋硬化させて、その後に前記含水吸水性ポリマの水分を脱水処理することを特徴とする多孔質紫外線硬化型樹脂組成物被覆電線の製造方法。 Coating the outer periphery of the metal conductor with an ultraviolet curable resin composition in which a water-absorbing water-absorbing polymer dispersed in water is dispersed;
A step of irradiating the ultraviolet curable resin composition coated on the outer periphery of the metal conductor with ultraviolet rays to crosslink and curing, and dehydrating the water-containing water-absorbing polymer to make it porous. In the method for producing a curable resin composition-coated electric wire,
In the first ultraviolet irradiation furnace for irradiating the ultraviolet curable resin composition with ultraviolet rays, the ultraviolet curable resin composition is irradiated with ultraviolet rays in a cooling liquid that cools the ultraviolet curable resin composition, followed by crosslinking and curing. A method for producing a porous ultraviolet curable resin composition-coated electric wire, comprising dehydrating a moisture of a polymer. 請求項１に記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記冷却液は水であることを特徴とする多孔質紫外線硬化型樹脂組成物被覆電線の製造方法。   2. The method for manufacturing a porous ultraviolet curable resin composition-coated electric wire according to claim 1, wherein the cooling liquid is water. 請求項１または２に記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記紫外線硬化型樹脂組成物の被覆された前記金属導体は、紫外線を照射する紫外線照射炉の、紫外線に対して透明な材料からなる透明管内に給排され又は充填されている前記冷却液中に導入されることを特徴とする多孔質紫外線硬化型樹脂組成物被覆電線の製造方法。   3. The method for producing a porous ultraviolet curable resin composition-coated electric wire according to claim 1 or 2, wherein the metal conductor coated with the ultraviolet curable resin composition is exposed to ultraviolet rays in an ultraviolet irradiation furnace that irradiates ultraviolet rays. On the other hand, a method for producing a porous ultraviolet curable resin composition-coated electric wire, which is introduced into the cooling liquid that is supplied or discharged into a transparent tube made of a transparent material. 請求項３に記載の多孔質紫外線硬化型樹脂組成物被覆電線の製造方法において、前記透明管は前記冷却液が給排され又は充填されている内管と前記内管を囲む外管とを有する二重管構造であって、前記外管内は乾燥ガス雰囲気または真空であることを特徴とする多孔質紫外線硬化型樹脂組成物被覆電線の製造方法。   4. The method for producing a porous ultraviolet curable resin composition-coated electric wire according to claim 3, wherein the transparent tube has an inner tube in which the cooling liquid is supplied or discharged and an outer tube surrounding the inner tube. A method for producing a porous ultraviolet curable resin composition-coated electric wire, characterized in that it has a double-tube structure, and the inside of the outer tube is a dry gas atmosphere or a vacuum.