JP2013010815A - Water-absorptive fine particle, porous film, porous film-covered wire, method for producing water-absorptive fine particle, method for producing porous film, and method for producing porous film-covered wire - Google Patents
Water-absorptive fine particle, porous film, porous film-covered wire, method for producing water-absorptive fine particle, method for producing porous film, and method for producing porous film-covered wire Download PDFInfo
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本発明は、吸水性微粒子、多孔質膜、多孔質膜被覆電線、吸水性微粒子の製造方法、多孔質膜の製造方法、および多孔質膜被覆電線の製造方法に関する。 The present invention relates to water-absorbing fine particles, a porous membrane, a porous membrane-coated electric wire, a method for producing water-absorbing fine particles, a method for producing a porous membrane, and a method for producing a porous membrane-coated electric wire.
吸水性微粒子は、紙おむつなどの衛生用品や農業用保水材、遮水材など多くの分野に利用されている。紙おむつなどに用いられる吸水性微粒子においては、吸水量が大きいことが求められている。 Water-absorbing fine particles are used in many fields such as sanitary goods such as disposable diapers, agricultural water retention materials, and water shielding materials. Water-absorbing fine particles used in paper diapers and the like are required to have a large water absorption amount.
また、吸水性微粒子は、上記紙おむつに限らず、絶縁性の多孔質膜の製造においても用いられる（例えば、特許文献１参照）。特許文献１においては、乾燥した吸水性微粒子を後に吸水させて用いる紙おむつの場合とは異なり、吸水性微粒子に予め吸水させ膨潤させてから用いる。具体的には、予め吸水させ膨潤させた吸水性微粒子を、紫外線硬化型樹脂前駆体に分散して塗液（ワニス）を調整する。調整されたワニスを導体の周囲に被覆させ、紫外線を照射し架橋硬化することによって、絶縁層を形成する。そして、絶縁層を乾燥し、吸水性微粒子中の水分を除去することによって、空孔を形成し、多孔質化された絶縁層（多孔質膜）を形成する。特許文献１によれば、物理的発泡や化学的発泡を用いないため、環境にやさしく容易に多孔質膜を製造することができる。 Further, the water-absorbing fine particles are not limited to the above-mentioned paper diaper, but are also used in the production of an insulating porous film (for example, see Patent Document 1). In Patent Document 1, unlike the case of a paper diaper in which dried water-absorbing fine particles are used for water absorption later, the water-absorbing fine particles are pre-absorbed and swollen before use. Specifically, the water-absorbing fine particles previously absorbed and swollen are dispersed in the ultraviolet curable resin precursor to adjust the coating liquid (varnish). The adjusted varnish is coated around the conductor, and irradiated with ultraviolet rays to be crosslinked and cured, thereby forming an insulating layer. Then, the insulating layer is dried to remove moisture in the water-absorbing fine particles, thereby forming pores and forming a porous insulating layer (porous film). According to Patent Document 1, since physical foaming or chemical foaming is not used, a porous film can be easily produced in an environmentally friendly manner.
しかしながら、特許文献１においては、乾燥した吸水性樹脂を微粉砕処理したものを、吸水性微粒子として用いるため、製造工程が複雑になる。
しかも、特許文献１の吸水性微粒子は、膨潤率が大きく空孔を形成できるが、乾燥状態での粒子径が大きく、粒子径のばらつき（粒子径分布）が大きい。この乾燥した吸水性微粒子は、吸水され吸水膨潤状態で用いられるが、吸水によって粒子径がさらに増加して不均一となり、粒子径分布が大きくなる。このため、特許文献１の方法で形成される多孔質膜は、空孔径が大きく、不均一なものとなり、潰れやすく、変形が生じやすい。また、空孔率が低く、低誘電率化が困難となる。この多孔質膜を電線の絶縁層として用いても、信号送信の高速化は困難である。
However, in Patent Document 1, since a finely pulverized dry water-absorbing resin is used as the water-absorbing fine particles, the manufacturing process becomes complicated.
Moreover, the water-absorbing fine particles of Patent Document 1 have a large swelling rate and can form pores, but have a large particle size in a dry state and a large variation in particle size (particle size distribution). The dried water-absorbing fine particles absorb water and are used in a water-absorbing swollen state, but due to water absorption, the particle size further increases and becomes non-uniform, and the particle size distribution increases. For this reason, the porous film formed by the method of Patent Document 1 has a large pore size, becomes non-uniform, is easily crushed, and is likely to be deformed. In addition, the porosity is low and it is difficult to reduce the dielectric constant. Even if this porous film is used as an insulating layer of an electric wire, it is difficult to increase the speed of signal transmission.
本発明は、このような問題を鑑みて成されたもので、その目的は、吸水膨潤状態での粒子径が均一で小さく、膨潤率が大きい吸水性微粒子およびその製造方法を提供することにある。また、吸水性微粒子を用いて形成され、均一で小さな空孔を有する多孔質膜および多孔質絶縁電線、並びにそれぞれを製造する方法を提供することにある。 The present invention has been made in view of such problems, and an object of the present invention is to provide water-absorbing fine particles having a uniform and small particle size in a water-absorbing swollen state and a high swelling rate, and a method for producing the same. . Another object of the present invention is to provide a porous film and a porous insulated wire that are formed using water-absorbing fine particles and have uniform and small pores, and a method for manufacturing each of them.
本発明の第１の態様は、予め吸水させた吸水膨潤状態の吸水性微粒子であって、不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物から重合され、重合の際に、前記組成物重量の１０倍重量以上の水を含水している吸水性微粒子である。 A first aspect of the present invention is a composition comprising water-absorbing fine particles in a water-absorbing swollen state that has been previously absorbed, and comprising an unsaturated organic acid, an unsaturated organic acid salt, an unsaturated amide, a crosslinking agent, and a polymerization initiator. And water-absorbing fine particles containing 10 times or more of water by weight of the composition during polymerization.
本発明の第２の態様は、第１の態様の吸水性微粒子において、吸水膨潤状態での最大粒子径が１００μｍ以下、平均粒子径が２０μｍ以下である吸水性微粒子である。 The second aspect of the present invention is the water-absorbent fine particle in the water-absorbent fine particle of the first aspect having a maximum particle diameter of 100 μm or less and an average particle diameter of 20 μm or less in the water-absorbing swollen state.
本発明の第３の態様は、第１の態様または第２の態様の吸水性微粒子を用いて空孔が形成された多孔質膜において、前記空孔は、該空孔を占めていた前記吸水性微粒子が吸水膨潤状態の水を放出することにより形成されている多孔質膜である。 According to a third aspect of the present invention, in the porous film in which pores are formed using the water-absorbing fine particles according to the first or second aspect, the pores occupy the pores. Is a porous film formed by releasing water in a water-absorbing swollen state.
本発明の第４の態様は、第３の態様の多孔質膜によって、導体が被覆されている多孔質膜被覆電線である。 A fourth aspect of the present invention is a porous film-coated electric wire in which a conductor is covered with the porous film of the third aspect.
本発明の第５の態様は、逆相懸濁重合法による吸水性微粒子の製造方法であって、不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物が前記組成物の重量の１０倍重量以上の水に溶解された水相と、水に不溶な有機溶剤を含む油相と、からなる混合物を攪拌し、油中水滴型のエマルジョンとした状態において、前記混合物を加熱、重合し、当該加熱重合の際に、前記組成物重量の１０倍重量以上の水を含水させることを特徴とする吸水性微粒子の製造方法である。 5th aspect of this invention is a manufacturing method of the water-absorbing microparticles | fine-particles by a reverse phase suspension polymerization method, Comprising: An unsaturated organic acid, unsaturated organic acid salt, unsaturated amide, a crosslinking agent, and a polymerization initiator are included. A mixture composed of an aqueous phase in which the composition is dissolved in water at least 10 times the weight of the composition and an oil phase containing an organic solvent insoluble in water is stirred to form a water-in-oil emulsion. In this state, the mixture is heated and polymerized, and the water-absorbing fine particles are produced by water containing at least 10 times the weight of the composition in the heat polymerization.
本発明の第６の態様は、第５の態様の吸水性微粒子の製造方法において、前記不飽和有機酸塩がアクリル酸またはメタクリル酸のナトリウム塩である吸水性微粒子の製造方法である。 A sixth aspect of the present invention is the method for producing water-absorbing fine particles according to the fifth aspect, wherein the unsaturated organic acid salt is a sodium salt of acrylic acid or methacrylic acid.
本発明の第７の態様は、第５の態様または第６の態様の吸水性微粒子の製造方法において、前記不飽和有機酸が、アクリル酸またはメタクリル酸である吸水性微粒子の製造方法である。 A seventh aspect of the present invention is the method for producing water-absorbing fine particles according to the fifth aspect or the sixth aspect, wherein the unsaturated organic acid is acrylic acid or methacrylic acid.
本発明の第８の態様は、第５〜第７の態様のいずれかの吸水性微粒子の製造方法において、前記不飽和アミドが、アクリルアミドまたはメタクリルアミドである吸水性微粒子の製造方法である。 An eighth aspect of the present invention is the method for producing water-absorbing fine particles according to any one of the fifth to seventh aspects, wherein the unsaturated amide is acrylamide or methacrylamide.
本発明の第９の態様は、第５〜第８の態様のいずれかの製造方法により得られる吸水性微粒子を用いて形成される多孔質膜の製造方法であって、前記吸水性微粒子が分散された紫外線硬化型樹脂前駆体に紫外線を照射して、前記紫外線硬化型樹脂前駆体を硬化させ、絶縁層を形成する工程と、前記絶縁層を乾燥させ、前記吸水性微粒子中の水を除去することによって、空孔を形成し、前記絶縁層を多孔質化する工程と、を含む多孔質膜の製造方法である。 A ninth aspect of the present invention is a method for producing a porous film formed using the water-absorbing fine particles obtained by the production method according to any of the fifth to eighth aspects, wherein the water-absorbing fine particles are dispersed. Irradiating the ultraviolet curable resin precursor with ultraviolet rays to cure the ultraviolet curable resin precursor and forming an insulating layer; drying the insulating layer; and removing water in the water-absorbing fine particles Forming a pore and making the insulating layer porous, thereby producing a porous film.
本発明の第１０の態様は、第５〜第８の態様のいずれかの製造方法により得られる吸水性微粒子を用いて形成される多孔質膜被覆電線の製造方法であって、前記吸水性微粒子が分散された紫外線硬化型樹脂前駆体を導体の外周に被覆する工程と、前記導体の外周に被覆された前記紫外線硬化型樹脂前駆体に紫外線を照射し、架橋硬化させて、絶縁層を形成する工程と、前記絶縁層を乾燥させ、前記吸水性微粒子中の水を除去することによって、空孔を形成し、前記絶縁層を多孔質化する工程と、を含む多孔質膜被覆電線の製造方法である。 A tenth aspect of the present invention is a method for producing a porous membrane-covered electric wire formed using the water-absorbing fine particles obtained by the production method according to any of the fifth to eighth aspects, wherein the water-absorbing fine particles A step of coating the outer periphery of the conductor with the UV curable resin precursor in which the resin is dispersed, and irradiating the UV curable resin precursor coated on the outer periphery of the conductor with ultraviolet rays to crosslink and cure to form an insulating layer A porous film-covered electric wire comprising: a step of drying the insulating layer and removing water in the water-absorbing fine particles, thereby forming pores and making the insulating layer porous Is the method.
本発明によれば、吸水膨潤状態での粒子径が均一で小さく、膨潤率が大きい吸水性微粒子を得ることができる。また、空孔の径が小さく均一な多孔質膜および多孔質膜被覆電線を得ることができる。 According to the present invention, water-absorbing fine particles having a uniform and small particle diameter in a water-absorbing swollen state and a large swelling rate can be obtained. In addition, it is possible to obtain a porous film having a small pore diameter and a porous membrane-coated electric wire.
上述したように、多孔質膜の空孔径は、吸水膨潤状態の吸水性微粒子の粒子径と同等になる。このため、均一で小さな空孔径を有する多孔質膜を形成するには、吸水膨潤状態での粒子径が均一で小さな吸水性微粒子を用いる必要性がある。すなわち、吸水膨潤状態の吸水性微粒子の粒子径を適正化する必要性がある。この点、本発明者らは、粒子径を適正化すべく、吸水性微粒子の製造方法について検討を行った。 As described above, the pore diameter of the porous membrane is equivalent to the particle diameter of the water-absorbing fine particles in the water-absorbing and swelling state. For this reason, in order to form a porous film having a uniform and small pore diameter, it is necessary to use water-absorbing fine particles having a uniform and small particle diameter in a water-absorbing swollen state. That is, it is necessary to optimize the particle diameter of the water-absorbing fine particles in a water-absorbing state. In this regard, the present inventors have studied a method for producing water-absorbing fine particles in order to optimize the particle diameter.
吸水性微粒子の製造方法としては、例えば、逆相懸濁重合法や分散重合法などがある。 Examples of the method for producing the water-absorbing fine particles include a reverse phase suspension polymerization method and a dispersion polymerization method.
逆相懸濁重合法は、特開昭５６−２５９２１号公報および特開昭５７−１５３０１０号公報に示すように、水溶性のモノマー成分が溶解された水と、水に溶解しない有機溶媒と、を機械的に攪拌し懸濁させて、油中水滴型のエマルジョン状態において重合する方法である。逆相懸濁重合法による吸水性微粒子は、水を含む水滴中で重合反応が生じるため、一部含水した状態の微粒子として重合される。特開平９−１２６１３号公報、特許２６１１１２５号公報、および特許２９３８９２０号公報によれば、粒子径が１００μｍ以上であって、１０倍以上の吸水特性を有する吸水性樹脂を得ることができる。
逆相懸濁重合法で得られる吸水性微粒子は、１０倍以上の吸水特性を有しており、高い膨潤率を有する。しかし、乾燥状態での粒子径が大きい上に、粒子径分布が広く（例えば、数十μｍから数百μｍまで）、ばらつきを有している。このため、従来の逆相懸濁重合法による吸水性微粒子は、多孔質膜の形成に適さない。
As shown in JP-A-56-25921 and JP-A-57-153010, the reversed-phase suspension polymerization method includes water in which a water-soluble monomer component is dissolved, an organic solvent insoluble in water, Is polymerized in a water-in-oil emulsion state by mechanically stirring and suspending. The water-absorbing fine particles obtained by the reverse phase suspension polymerization method are polymerized as fine particles partially containing water because a polymerization reaction occurs in water droplets containing water. According to Japanese Patent Application Laid-Open Nos. 9-12613, 261125, and 29389920, a water-absorbing resin having a particle diameter of 100 μm or more and 10 times or more water-absorbing characteristics can be obtained.
The water-absorbing fine particles obtained by the reverse-phase suspension polymerization method have a water absorption property of 10 times or more and a high swelling rate. However, the particle size in a dry state is large, and the particle size distribution is wide (for example, from several tens of μm to several hundreds of μm), and there are variations. For this reason, the water-absorbing fine particles by the conventional reverse phase suspension polymerization method are not suitable for forming a porous film.
分散重合法（沈殿重合法）は、原料である単量体や重合開始剤を溶媒に溶解させた後に加熱重合して、重合により高分子量化したポリマを析出させ、微粒子として沈殿させる重合方法である（例えば、特開平１−３１５４０８号参照）。分散重合法によって、水膨潤状態における粒子径が０．１〜１０μｍの親水性ゲル微粒子（吸水性微粒子）を得ることができる。
分散重合法により得られる吸水性微粒子は、粒子径が小さく、粒子径のばらつきも小さいため、小さく均一な空孔を形成できるものと考えられる。しかし、実際には、膨潤率が小さく、吸水膨潤状態からの収縮率が小さい。このため、この吸水性微粒子を多孔質膜の製造に用いても、空孔を形成しにくく、均一な空孔径の多孔質膜の形成は困難である。
The dispersion polymerization method (precipitation polymerization method) is a polymerization method in which monomers and polymerization initiators as raw materials are dissolved in a solvent and then heat-polymerized to precipitate a polymer having a high molecular weight by polymerization and precipitate as fine particles. (For example, see JP-A-1-315408). By the dispersion polymerization method, hydrophilic gel fine particles (water-absorbing fine particles) having a particle diameter of 0.1 to 10 μm in a water-swelled state can be obtained.
Since the water-absorbing fine particles obtained by the dispersion polymerization method have a small particle size and a small variation in particle size, it is considered that small and uniform pores can be formed. However, actually, the swelling rate is small, and the shrinkage rate from the water-absorbing swelling state is small. For this reason, even if this water-absorbing fine particle is used in the production of a porous film, it is difficult to form pores, and it is difficult to form a porous film having a uniform pore diameter.
このように、従来の製造方法により得られる吸水性微粒子では、吸水膨潤状態での粒子径と膨潤率とをともに適正化することは困難であった。これは、乾燥状態の吸水性微粒子の粒子径や吸水量を評価するだけで、吸水膨潤による粒子径の変動について考慮していないためである。 As described above, it is difficult for the water-absorbing fine particles obtained by the conventional production method to optimize both the particle diameter and the swelling rate in the water-absorbing swollen state. This is because only the particle diameter and the amount of water absorption of the water-absorbing fine particles in the dry state are evaluated, and the change in the particle diameter due to the water absorption swelling is not taken into consideration.
そこで、本発明者らは、一部含水状態の吸水性微粒子が形成される逆相懸濁重合法に着目した。逆相懸濁重合法においては、モノマー成分を溶解する水の添加量を調整することによって、形成される吸水性微粒子の含水量を調整することができる。この点、おむつ用の吸水性微粒子は、重合された後に脱水・乾燥されるため、水の添加量が少なかった。一方、多孔質膜の製造用の吸水性微粒子は、吸水させ膨潤状態で用いられるため、水の添加
量は問題とならない。むしろ、水の添加量を増加させ、膨潤状態まで水を吸水させて重合する方が、膨潤状態で比較的小さく、均一な粒径を有する吸水性微粒子を得ることができる。従来の水の添加量が少ない状態での逆相懸濁重合法では、重合後の吸水性微粒子は粒径が小さいものの、さらに吸水することが可能であり、吸水後に粒径が大きくなってしまう。そうすると、目的とする粒径とするためには、吸水性微粒子を粉砕する粉砕工程などをさらに設ける必要があり、製造工程が増加することになる。
Therefore, the present inventors have paid attention to a reverse phase suspension polymerization method in which partially water-containing water-absorbing fine particles are formed. In the reverse phase suspension polymerization method, the water content of the formed water-absorbing fine particles can be adjusted by adjusting the amount of water that dissolves the monomer component. In this respect, since the water-absorbing fine particles for diapers are dehydrated and dried after being polymerized, the amount of water added is small. On the other hand, since the water-absorbing fine particles for producing the porous membrane absorb water and are used in a swollen state, the amount of water added is not a problem. Rather, it is possible to obtain water-absorbing fine particles having a relatively small and uniform particle size in the swollen state by increasing the amount of water added and absorbing the water to the swollen state for polymerization. In the conventional reversed-phase suspension polymerization method with a small amount of water added, although the water-absorbing fine particles after polymerization have a small particle size, they can further absorb water, and the particle size becomes large after water absorption. . Then, in order to obtain the target particle size, it is necessary to further provide a pulverization step for pulverizing the water-absorbing fine particles, which increases the number of manufacturing steps.
以上のことから、本発明者らは、逆相懸濁重合法において、水の添加量を増加させ、膨潤状態の吸水性微粒子を形成することによって、膨潤状態での粒子径と膨潤率との関係について検討した。具体的には、従来の逆相懸濁重合法と比較して、モノマー成分を溶解する水の量を増加させ、重合の際に吸水させることで、吸水性微粒子を構成する組成物重量の１０倍重量以上の水を含水した、吸水膨潤状態の吸水性微粒子を形成した。その結果、吸水膨潤状態の吸水性微粒子を形成できる上に、吸水膨潤状態での粒子径および膨潤率を適正化できることを見出し、本発明を創作するに至った。 From the above, the present inventors increased the amount of water added in the reverse phase suspension polymerization method to form the swollen water-absorbing fine particles, whereby the particle diameter and the swelling ratio in the swollen state were The relationship was examined. Specifically, as compared with the conventional reverse phase suspension polymerization method, the amount of water that dissolves the monomer component is increased, and water is absorbed during the polymerization, so that the weight of the composition constituting the water-absorbing fine particles is 10%. Water-absorbing fine particles in a water-absorbing swollen state containing water more than double weight were formed. As a result, it was found that water-absorbing fine particles in a water-absorbing swollen state can be formed, and that the particle diameter and swelling rate in the water-absorbing swollen state can be optimized, and the present invention has been created.
以下に、本発明の一実施形態にかかる吸水性微粒子およびその製造方法について説明する。 Hereinafter, water-absorbing fine particles and a method for producing the same according to an embodiment of the present invention will be described.
（吸水性微粒子）
本発明の一実施形態にかかる吸水性微粒子は、予め吸水させた吸水膨潤状態の吸水性微粒子であって、不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物から重合され、当該重合の際に、前記組成物重量の１０倍重量以上の水を含水している。
(Water-absorbing fine particles)
Water-absorbing fine particles according to an embodiment of the present invention are water-absorbing fine particles in a water-absorbing swollen state that have been absorbed beforehand, and are unsaturated organic acid, unsaturated organic acid salt, unsaturated amide, crosslinking agent, and polymerization initiator The composition is polymerized from the composition containing water, and water of 10 times or more weight of the composition weight is contained in the polymerization.
不飽和有機酸は、重合される吸水性微粒子の原料であり、水溶性のものが選択される。不飽和有機酸としては、例えば、アクリル酸またはメタクリル酸が好ましい。 The unsaturated organic acid is a raw material for the water-absorbing fine particles to be polymerized, and a water-soluble one is selected. As the unsaturated organic acid, for example, acrylic acid or methacrylic acid is preferable.
不飽和有機酸塩は、吸水性微粒子の吸水性を向上させるものであって、アクリル酸またはメタクリル酸の塩が好ましい。特に、入手性や、吸水性の点から、アクリル酸またはメタクリル酸のナトリウム塩が好ましい。 The unsaturated organic acid salt improves water absorption of the water-absorbing fine particles, and a salt of acrylic acid or methacrylic acid is preferable. In particular, sodium salt of acrylic acid or methacrylic acid is preferable from the viewpoint of availability and water absorption.
不飽和アミドとしては、アクリルアミドまたはメタクリルアミドが好ましい。 As the unsaturated amide, acrylamide or methacrylamide is preferable.
架橋剤としては、メチレンビスアクリルアミドやメチレンビスメタクリルアミドなどが好ましい。 As the crosslinking agent, methylene bisacrylamide and methylene bismethacrylamide are preferable.
重合開始剤としては、水溶性のものであれば限定されず、例えば、Ｎ，Ｎ’−アゾビスイソブチロニトリル、Ｎ，Ｎ’−アゾビスイソバレロニトリル、アゾビス（イソ酪酸）ジメチル等のアゾビス系化合物や、ベンゾイルパーオキサイド、ラウロイルパーオキサイド、ジクミルパーオキサイドなどの有機過酸化物系化合物や、過硫酸アンモニウム、過硫酸カリウムなどの過硫酸系化合物を用いることができる。 The polymerization initiator is not limited as long as it is water-soluble, and examples thereof include N, N′-azobisisobutyronitrile, N, N′-azobisisovaleronitrile, and azobis (isobutyric acid) dimethyl. An azobis compound, an organic peroxide compound such as benzoyl peroxide, lauroyl peroxide, and dicumyl peroxide, and a persulfate compound such as ammonium persulfate and potassium persulfate can be used.
本実施形態において、吸水性微粒子は、重合の際に、吸水性微粒子を構成する組成物重量の１０倍重量以上の水を含んでいる。
“重合の際に”とは、吸水性微粒子が吸水膨潤状態まで水を含む段階が、吸水性微粒子を重合する時であって、この時点で上記規定量の水を含水していることである。すなわち、吸水性微粒子は、所定量の水を含水して、吸水膨潤状態となった吸水性微粒子として重合される。しかも、吸水膨潤状態での粒子径が制御された吸水性微粒子となっている。この吸水性微粒子は、十分に含水しており、大きな吸水能力を有さないため、吸水にともなう粒子径の変動が少なく、粒子径のばらつきも少ない。一方、従来の吸水性微粒子におい
ては、重合された時点での水の吸水量（含水量）が少なく、大きな吸水能力を有するため、吸水にともなう粒子径の変動が大きく、粒子径のばらつきも大きくなる。
したがって、本実施形態の吸水性微粒子は、従来の吸水性微粒子と比較して、吸水膨潤状態での粒子径が小さく均一であって、吸水にともなう粒子径の変動が少ない。
In the present embodiment, the water-absorbing fine particles contain water at least 10 times the weight of the composition constituting the water-absorbing fine particles during polymerization.
“At the time of polymerization” means that the stage in which the water-absorbing fine particles contain water until the water-absorbing and swelling state is the time when the water-absorbing fine particles are polymerized, and at this point, the above-mentioned prescribed amount of water is contained. . That is, the water-absorbing fine particles are polymerized as water-absorbing fine particles containing a predetermined amount of water and in a water-absorbing swollen state. In addition, the water-absorbing fine particles have a controlled particle size in the water-absorbing swollen state. Since the water-absorbing fine particles are sufficiently water-containing and do not have a large water-absorbing ability, there are few fluctuations in the particle diameter due to water absorption, and there is little variation in the particle diameter. On the other hand, the conventional water-absorbing fine particles have a small water absorption amount (water content) at the time of polymerization and a large water absorption capability, so that the particle size variation due to water absorption is large and the particle size variation is also large. Become.
Therefore, the water-absorbing fine particles of the present embodiment have a small and uniform particle size in the water-absorbing swollen state compared to conventional water-absorbing fine particles, and the variation in the particle size due to water absorption is small.
吸水性微粒子の含水量は、重合される吸水性微粒子の吸水倍率以下の範囲内において、できるだけ多いことが好ましい。ここで、吸水倍率は、単位当たりの吸水性微粒子において、吸水される水分量が、吸水性微粒子の重量に対して何倍であるかを示しており、下記式で算出される。
（吸水倍率）＝（吸水後のポリマの質量）／（乾燥時のポリマの質量）
この吸水倍率は、吸水性微粒子の原料組成によって変化するため、特に限定されないが、本実施形態における不飽和有機酸などを含む組成物の場合、組成物の全重量の１００倍重量以下の水であれば、重合される吸水性微粒子の吸水倍率以下の範囲内とすることができる。つまり、吸水性微粒子の含水量は、組成物重量の１０倍重量以上１００倍重量以下とすることが好ましい。含水量が１０倍重量よりも小さいと、吸水性微粒子は、十分に膨潤した状態とはならず、さらに多量の水を吸水できる余地を残している。すなわち、浸水により、さらに多量の水を吸水し、重合時に制御した粒子径が大きく増加し、粒子径がばらつくことになる。一方、吸水性微粒子は、吸水倍率を超えて吸水することはないので、含水量が１００倍重量よりも大きくなると、吸水性微粒子の強度が弱くなり、紫外線硬化型樹脂前駆体中に分散、塗布し、硬化させる際に吸水性微粒子が潰れてしまう。
The water content of the water-absorbing fine particles is preferably as large as possible within the range of the water absorption fine particle to be polymerized or less. Here, the water absorption ratio indicates how many times the amount of water absorbed in the water-absorbing fine particles per unit is larger than the weight of the water-absorbing fine particles, and is calculated by the following equation.
(Water absorption ratio) = (Mass of polymer after water absorption) / (Mass of polymer when dried)
The water absorption ratio varies depending on the raw material composition of the water-absorbing fine particles, and is not particularly limited. However, in the case of a composition containing an unsaturated organic acid or the like in the present embodiment, the amount of water is 100 times or less the total weight of the composition. If it exists, it can be in the range below the water absorption magnification of the water-absorbing fine particles to be polymerized. That is, the water content of the water-absorbing fine particles is preferably 10 to 100 times the weight of the composition. If the water content is less than 10 times the weight, the water-absorbing fine particles are not sufficiently swollen, leaving a room for absorbing a larger amount of water. That is, a larger amount of water is absorbed by the water immersion, and the particle diameter controlled at the time of polymerization greatly increases and the particle diameter varies. On the other hand, since the water-absorbing fine particles do not absorb water exceeding the water absorption ratio, if the water content exceeds 100 times the weight, the strength of the water-absorbing fine particles becomes weak and dispersed and coated in the UV curable resin precursor. In addition, the water-absorbing fine particles are crushed when cured.
含水量を上記範囲内とすることによって、吸水膨潤状態の吸水性微粒子の含水量を好適に調節して、吸水にともなう粒子径の変動がより少ない吸水性微粒子を得ることができる。 By setting the water content within the above range, it is possible to suitably adjust the water content of the water-absorbing fine particles in a water-absorbing swollen state, and to obtain water-absorbing fine particles with less variation in particle diameter due to water absorption.
また、本実施形態の吸水性微粒子は、吸水膨潤状態での最大粒子径は１００μｍ以下、その平均粒子径は２０μｍ以下であることが好ましい。最大粒子径が１００μｍよりも大きくなると、これらを紫外線硬化型樹脂前駆体に分散させた塗料を塗布して、１００μｍ以下の多孔質膜を形成する場合に、ピンホールや膜厚のムラが生じる。また、平均粒子径が２０μｍよりも大きくなると、前述の１００μｍ以上の粒子径の吸水性微粒子の混入確率が高くなり、ピンホールや膜厚のムラが生じる。しかも、紫外線硬化型樹脂前駆体に分散させたときに塗布性が悪くなるとともに、形成される空孔が粗大となり、潰れやすくなる。 Further, the water-absorbing fine particles of the present embodiment preferably have a maximum particle size of 100 μm or less and an average particle size of 20 μm or less in a water-absorbing swollen state. When the maximum particle diameter is larger than 100 μm, pinholes and film thickness unevenness occur when a porous film having a thickness of 100 μm or less is formed by applying a coating material in which these are dispersed in an ultraviolet curable resin precursor. On the other hand, when the average particle diameter is larger than 20 μm, the mixing probability of the water-absorbing fine particles having a particle diameter of 100 μm or more is increased, and pinholes and film thickness unevenness are generated. In addition, when dispersed in the ultraviolet curable resin precursor, the coatability is deteriorated, and the formed pores become coarse and easily crushed.
（吸水性微粒子の製造方法）
上記実施形態の吸水性微粒子は、以下のような製造方法により形成される。
(Method for producing water-absorbing fine particles)
The water-absorbing fine particles of the above embodiment are formed by the following manufacturing method.
本発明の一実施形態にかかる吸水性微粒子の製造方法は、逆相懸濁重合法により、不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物が前記組成物の重量の１０倍重量以上の水に溶解された水相と、水に不溶な有機溶剤を含む油相と、からなる混合物を攪拌し、油中水滴型のエマルジョンとした状態において、前記混合物を加熱、重合し、当該加熱重合の際に、前記組成物重量の１０倍重量以上の水を含水させる。 A method for producing water-absorbing fine particles according to an embodiment of the present invention includes a composition comprising an unsaturated organic acid, an unsaturated organic acid salt, an unsaturated amide, a crosslinking agent, and a polymerization initiator by a reverse phase suspension polymerization method. Is a water-in-oil emulsion in which a mixture of an aqueous phase dissolved in water at least 10 times the weight of the composition and an oil phase containing an organic solvent insoluble in water is stirred. The mixture is heated and polymerized, and at the time of the heat polymerization, water containing 10 times or more weight of the composition is added with water.
逆相懸濁重合法とは、重合に不活性な疎水性の有機溶剤（油相）中で、水溶性の単量体（不飽和有機酸）を懸濁させて重合を行う方法である。具体的には、図１（ａ）に示すように、不飽和有機酸や重合開始剤などを含む水相１１と、重合に不活性な疎水性の有機溶剤を含む油相１０と、を混合する。水相１１と油相１０との混合物を混合攪拌することにより、水相１１が油相１０中に懸濁し、分散した油中水滴型のエマルジョン（逆相エマルジョン）状態を形成する。油中水滴型のエマルジョン状態は、図１（ｂ）に示すように、
水相１１が水滴１２として、油相１０中に分散した状態である。そして、このエマルジョン状態の混合物を加熱し、水滴１２内において、単量体である不飽和有機酸などを重合することによって、吸水性微粒子を形成する。
The reverse phase suspension polymerization method is a method of performing polymerization by suspending a water-soluble monomer (unsaturated organic acid) in a hydrophobic organic solvent (oil phase) inert to polymerization. Specifically, as shown in FIG. 1A, an aqueous phase 11 containing an unsaturated organic acid or a polymerization initiator and an oil phase 10 containing a hydrophobic organic solvent inert to the polymerization are mixed. To do. By mixing and stirring the mixture of the water phase 11 and the oil phase 10, the water phase 11 is suspended in the oil phase 10 to form a dispersed water-in-oil emulsion (reverse phase emulsion) state. The water-in-oil type emulsion state is as shown in FIG.
The water phase 11 is in the state of being dispersed in the oil phase 10 as water droplets 12. Then, the emulsion-like mixture is heated to polymerize the unsaturated organic acid as a monomer in the water droplets 12, thereby forming water-absorbing fine particles.
まず、不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤をそれぞれ選択し、これらを含む組成物を調整する。 First, an unsaturated organic acid, an unsaturated organic acid salt, an unsaturated amide, a crosslinking agent, and a polymerization initiator are selected, and a composition containing them is prepared.
続いて、不飽和有機酸などを含む組成物に、組成物の重量の１０倍重量以上の水を添加して溶解し、水相１１を調整する。この際に添加する水は、重合により得られる吸水性微粒子中に含まれることになる。このため、添加する水の量は、重合される吸水性微粒子に含水させる量によって調整される。上述したように、吸水性微粒子は、１０倍重量以上１００倍重量以下となる場合に、粒子径が均一で小さく、吸水にともなう変動が少なくなる。したがって、添加する水の量は、１０倍重量以上１００倍重量以下とすることが好ましい。
添加する水の量を、１０倍重量よりも小さくすると、形成される吸水性微粒子は、十分に膨潤した状態とはならず、さらに多量の吸水能力を有することになる。その結果、浸水により、さらに多量の水を吸水し、重合時に制御した粒子径が大きく増加し、粒子径がばらつくことになる。一方、１００倍重量よりも大きくすると、重合される吸水性微粒子の強度が弱くなり、紫外線硬化型樹脂前駆体中に分散し、塗布、硬化される際に、吸水性微粒子のゲルが破壊されてしまう恐れがある。しかも、組成物が水に対して希薄となるため、吸水性微粒子の形成が困難となる。
Subsequently, water of at least 10 times the weight of the composition is added to and dissolved in the composition containing an unsaturated organic acid, and the aqueous phase 11 is adjusted. The water added at this time is contained in the water-absorbing fine particles obtained by polymerization. For this reason, the amount of water to be added is adjusted by the amount of water contained in the water-absorbing fine particles to be polymerized. As described above, when the water-absorbing fine particles are 10 times or more and 100 times or less the weight, the particle diameter is uniform and small, and fluctuation due to water absorption is reduced. Therefore, the amount of water to be added is preferably 10 times or more and 100 times or less.
If the amount of water to be added is less than 10 times the weight, the water-absorbing fine particles formed will not be sufficiently swollen and will have a greater amount of water absorption. As a result, a larger amount of water is absorbed by the water immersion, and the particle size controlled during the polymerization is greatly increased, resulting in a variation in the particle size. On the other hand, when the weight is more than 100 times, the strength of the water-absorbing fine particles to be polymerized is weakened and dispersed in the ultraviolet curable resin precursor, and the gel of the water-absorbing fine particles is broken when applied and cured. There is a risk. In addition, since the composition is diluted with water, it becomes difficult to form water-absorbing fine particles.
一方、油相として、水に不溶な有機溶剤を用意する。使用する有機溶剤としては、水に不溶であることが必要であり、逆相エマルジョンを安定に形成することが求められる。例えば、ｎ- ヘキサン、シクロヘキサン、石油エーテルなど挙げられる。
また、油相としての有機溶剤に、界面活性剤を添加してもよい。界面活性剤は、水相と油相との２相間のエネルギー状態（界面張力）を小さくして、逆相エマルジョンを安定させることができる。界面活性剤としては、例えば、ソルビタンアルキレート化合物、ポリオキシアルキレンエーテル化合物、シリコーン系化合物、ふっ素系化合物などを用いることができる。
On the other hand, an organic solvent insoluble in water is prepared as the oil phase. The organic solvent to be used needs to be insoluble in water, and is required to form a reversed-phase emulsion stably. For example, n-hexane, cyclohexane, petroleum ether and the like can be mentioned.
Further, a surfactant may be added to the organic solvent as the oil phase. The surfactant can stabilize the inverse emulsion by reducing the energy state (interface tension) between the two phases of the aqueous phase and the oil phase. As the surfactant, for example, a sorbitan alkylate compound, a polyoxyalkylene ether compound, a silicone compound, a fluorine compound, or the like can be used.
続いて、上記水相と油相との混合物を攪拌混合することにより、油中水滴型のエマルジョン（逆相エマルジョン）を形成する。この水滴１２は、水相１１と同じ組成であり、吸水性微粒子となるモノマー成分（不飽和有機酸など）と、所定量の水と、が含有されている。エマルジョン状態において、混合物を加熱して、水滴１２内のモノマー成分を重合反応することによって、吸水膨潤状態の吸水性微粒子を形成する。なお、吸水性微粒子の粒子径は、混合物を攪拌する回転速度や界面活性剤の添加量を調節することにより、適宜制御される。 Subsequently, the mixture of the water phase and the oil phase is stirred and mixed to form a water-in-oil type emulsion (reverse phase emulsion). The water droplet 12 has the same composition as the water phase 11 and contains a monomer component (such as an unsaturated organic acid) that becomes water-absorbing fine particles and a predetermined amount of water. In the emulsion state, the mixture is heated to polymerize the monomer component in the water droplets 12 to form water-absorbing fine particles in a water-absorbing swollen state. The particle diameter of the water-absorbing fine particles is appropriately controlled by adjusting the rotational speed at which the mixture is stirred and the amount of surfactant added.
最後に、攪拌を停止し、分離後の上澄みとなる油相１０（有機溶剤など）を除去することにより、本実施形態における、吸水膨潤状態の吸水性微粒子を得る。この吸水性微粒子は、十分に膨潤した状態での粒子径が小さく、均一である。 Finally, stirring is stopped, and the oil phase 10 (organic solvent or the like) that becomes the supernatant after separation is removed, thereby obtaining water-absorbing fine particles in a water-absorbing state in this embodiment. The water-absorbing fine particles have a small particle diameter in a sufficiently swollen state and are uniform.
本実施形態の逆相懸濁重合法により形成される吸水性微粒子が小さくなる理由は以下のことが推測される。
上述したように、逆相懸濁重合においては、水滴内で重合反応が生じ、吸水性微粒子が形成される。このため、水滴の大きさ（体積）が小さいほど、重合される吸水性微粒子の大きさ（粒子径）は小さくなる。これは、水滴の体積が減少することによって、水滴内に含まれるモノマー成分量が減少し、重合されるポリマ（吸水性微粒子）が小さくなるためである。
この点、従来の水相（水滴）には、モノマー成分の１重量に対して、２倍重量の水が添加されており、モノマー成分の濃度は１／３となっている（後述する比較例１を参照）。これに対して、本実施形態の水相（水滴）には、モノマー成分の１重量に対して、５０倍重量（１０倍重量以上）の水が添加されており、モノマー成分の濃度は１／５１となっている（後述する実施例１を参照）。すなわち、本実施形態においては、水相中のモノマー成分の濃度が希釈されて低くなっており、水滴の単位体積あたりに含まれるモノマー成分量が、従来と比較して少ない。このため、本実施形態の吸水性微粒子は、吸水膨潤状態での粒子径が従来と比較して小さく形成されることになる。
The reason why the water-absorbing fine particles formed by the reversed-phase suspension polymerization method of the present embodiment is small is estimated as follows.
As described above, in reverse phase suspension polymerization, a polymerization reaction occurs in water droplets, and water-absorbing fine particles are formed. For this reason, the size (particle diameter) of the water-absorbing fine particles to be polymerized becomes smaller as the size (volume) of the water droplet is smaller. This is because when the volume of the water droplet is reduced, the amount of monomer components contained in the water droplet is reduced, and the polymer (water-absorbing fine particles) to be polymerized is reduced.
In this regard, in the conventional aqueous phase (water droplets), twice the weight of water is added to 1 weight of the monomer component, and the concentration of the monomer component is 1/3 (Comparative Example described later). 1). On the other hand, the water phase (water droplets) of the present embodiment is added with 50 times weight (10 times weight or more) of water with respect to 1 weight of the monomer component, and the concentration of the monomer component is 1 / 51 (see Example 1 described later). That is, in the present embodiment, the concentration of the monomer component in the aqueous phase is diluted and lowered, and the amount of the monomer component contained per unit volume of the water droplet is small compared to the conventional case. For this reason, the water-absorbing fine particles of the present embodiment are formed to have a smaller particle size in the water-absorbing swollen state compared to the conventional case.
また、本実施形態の逆相懸濁重合法により形成される吸水性微粒子が、ばらつきが少なく、比較的均一となる理由は以下のことが推測される。
逆相懸濁重合法においては、攪拌により生じる複数の水滴は均一の大きさ（体積）ではなく、水滴中のモノマー成分量は均一でない。複数の水滴中で形成される吸水性微粒子の粒子径は均一とはならず、多少のばらつきを有することになる。このばらつきが粒子径分布の広がりとなり、吸水性微粒子は所定の粒子径範囲を有することになる。
上述したように、従来においては、水滴中のモノマー成分の濃度が高い。このため、水滴の体積の相違がモノマー成分量の相違に大きく反映され、吸水性微粒子の粒子径が大きくばらつくことになる。これに対して、本実施形態においては、水滴中のモノマー成分の濃度が低く、水滴の体積の相違にともなう水滴中のモノマー成分量の相違が抑制される。すなわち、本実施形態の吸水性微粒子は、粒子径のばらつきが抑制され、比較的均一な粒子径を有することになる。
Moreover, the reason why the water-absorbing fine particles formed by the reverse phase suspension polymerization method of the present embodiment is relatively uniform with little variation is assumed as follows.
In the reverse phase suspension polymerization method, the plurality of water droplets generated by stirring are not uniform in size (volume), and the amount of monomer components in the water droplets is not uniform. The particle diameter of the water-absorbing fine particles formed in a plurality of water droplets is not uniform and has some variation. This variation results in a broadening of the particle size distribution, and the water-absorbing fine particles have a predetermined particle size range.
As described above, conventionally, the concentration of the monomer component in the water droplet is high. For this reason, the difference in the volume of the water droplet is largely reflected in the difference in the amount of the monomer component, and the particle diameter of the water-absorbing fine particles greatly varies. On the other hand, in this embodiment, the concentration of the monomer component in the water droplet is low, and the difference in the amount of the monomer component in the water droplet due to the difference in the volume of the water droplet is suppressed. That is, the water-absorbing fine particles of the present embodiment have a relatively uniform particle size with variations in particle size suppressed.
以上をまとめると、本実施形態の吸水性微粒子の製造方法においては、不飽和有機酸を含む組成物を、その重量の１０倍重量以上の水に溶解し、水相としている。このため、重合に際して、吸水性微粒子の粒子径を小さく、均一とすることができる。しかも、重合と同時に、吸水膨潤状態として水を含水させることができるので、多孔質膜の製造において、従来のように市販の吸水性微粒子に吸水させる吸水工程を省略することができる。さらに、本実施形態の吸水性微粒子の製造方法によれば、重合時に十分な量の水を吸水させることで、十分に膨潤した状態での吸水性微粒子の粒子径を制御することができる。このため、従来の重合法で製造した吸水性微粒子のように、さらに吸水しても粒子径が大きく増大することがなく、粉砕工程を省略することができる。 In summary, in the method for producing water-absorbing fine particles of the present embodiment, a composition containing an unsaturated organic acid is dissolved in 10 times or more by weight of water to form an aqueous phase. For this reason, the particle diameter of the water-absorbing fine particles can be made small and uniform during the polymerization. Moreover, since water can be contained in the water-absorbing swollen state simultaneously with the polymerization, the water-absorbing step of absorbing water in the commercially available water-absorbing fine particles as in the prior art can be omitted in the production of the porous membrane. Furthermore, according to the method for producing water-absorbing fine particles of the present embodiment, the particle diameter of the water-absorbing fine particles in a sufficiently swollen state can be controlled by absorbing a sufficient amount of water during polymerization. For this reason, unlike the water-absorbing fine particles produced by the conventional polymerization method, the particle diameter does not increase greatly even if water is further absorbed, and the pulverization step can be omitted.
（多孔質膜）
次に、上述した吸水性微粒子を用いて形成される多孔質膜およびその製造方法について説明する。
(Porous membrane)
Next, a porous film formed using the water-absorbing fine particles described above and a method for manufacturing the same will be described.
本発明の一実施形態にかかる多孔質膜は上記吸水性微粒子を用いて空孔が形成されており、空孔は、空孔を占めていた吸水性微粒子が吸水膨潤状態の水を放出することにより形成されている。上述したように、上記実施形態にかかる吸水性微粒子は、吸水膨潤状態での粒子径が小さく均一であり、膨潤率が大きい。この吸水性微粒子によって形成される多孔質膜の空孔は、小さく、均一な空孔径を有している。そして、空孔径が大きすぎないため、多孔質膜はつぶれにくく、変形しにくい。 In the porous membrane according to an embodiment of the present invention, pores are formed using the water-absorbing fine particles, and the water-absorbing fine particles occupying the pores release water in a water-absorbing and swollen state. It is formed by. As described above, the water-absorbing fine particles according to the above embodiment have a small and uniform particle diameter in the water-absorbing swollen state and a large swelling rate. The pores of the porous film formed by the water-absorbing fine particles are small and have a uniform pore diameter. And since the pore diameter is not too large, the porous film is not easily crushed and is not easily deformed.
上記多孔質膜は、以下の製造方法により形成される。
まず、上述した吸水性微粒子の製造方法により、吸水膨潤状態まで水が含水された吸水性微粒子を準備する。吸水性微粒子は、吸水膨潤状態であるため、従来必要とされた、吸水性微粒子の吸水工程を省略することができる。この吸水性微粒子を、液状の紫外線硬化型樹脂前駆体に分散させて、吸水性微粒子含有の紫外線硬化型樹脂前駆体を調整する。
The porous membrane is formed by the following manufacturing method.
First, water-absorbing fine particles containing water up to a water-absorbing swollen state are prepared by the method for producing water-absorbing fine particles described above. Since the water-absorbing fine particles are in a water-absorbing swollen state, the water-absorbing step of the water-absorbing fine particles that has been conventionally required can be omitted. The water-absorbing fine particles are dispersed in a liquid ultraviolet curable resin precursor to prepare a water-absorbing fine particle-containing ultraviolet curable resin precursor.
紫外線硬化型樹脂前駆体としては、特に限定されず、紫外線により架橋硬化するもので
あれば良い。樹脂としては、例えば、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を選択できるが、樹脂前駆体の成分の誘電率が４以下であることが好ましく、３以下であることがさらに好ましい。また、紫外線硬化型樹脂前駆体に添加される光重合開始剤は、公知のものから選択される。
The ultraviolet curable resin precursor is not particularly limited as long as it can be crosslinked and cured by ultraviolet rays. As the resin, for example, known resins such as urethane, silicone, fluorine, epoxy, polyester, and polycarbonate can be selected, and the dielectric constant of the resin precursor component is preferably 4 or less. More preferably, it is as follows. The photopolymerization initiator added to the ultraviolet curable resin precursor is selected from known ones.
続いて、吸水性微粒子含有の紫外線硬化型樹脂前駆体をガラス板上に塗布する。紫外線硬化型樹脂前駆体に紫外線を照射して、架橋硬化させて、絶縁層を形成する。この絶縁層は、硬化した紫外線硬化型樹脂中に、吸水膨潤状態まで水を含水した吸水性微粒子が分散した構造となっている。その後、絶縁層を加熱して、吸水性微粒子中の水を脱水除去する。水の脱水除去とともに、吸水膨潤状態の吸水性微粒子の占有していた領域は空孔となる。すなわち、吸水性微粒子の分散された絶縁層は、水の脱水除去により多孔質化され、多孔質膜となる。なお、空孔の径は、吸水膨潤状態の吸水性微粒子の大きさと同等となる。 Subsequently, an ultraviolet curable resin precursor containing water-absorbing fine particles is applied on the glass plate. The ultraviolet curable resin precursor is irradiated with ultraviolet rays to be crosslinked and cured to form an insulating layer. This insulating layer has a structure in which water-absorbing fine particles containing water to a water-absorbing swelling state are dispersed in a cured ultraviolet curable resin. Thereafter, the insulating layer is heated to dehydrate and remove the water in the water-absorbing fine particles. Along with the dehydration and removal of water, the area occupied by the water-absorbing fine particles in the water-absorbing swollen state becomes pores. That is, the insulating layer in which the water-absorbing fine particles are dispersed is made porous by dehydration and removal of water to form a porous film. The diameter of the pores is equivalent to the size of the water-absorbing fine particles in the water-absorbing and swelling state.
上記多孔質膜は、電線の導体を被覆する絶縁層、特に低誘電率特性が求められる高周波信号用電線の絶縁体に用いられる。 The porous film is used for an insulating layer that covers a conductor of an electric wire, particularly an insulator for a high-frequency signal electric wire that requires low dielectric constant characteristics.
（多孔質膜被覆電線）
次に、上述した吸水性微粒子を用いて形成される多孔質膜被覆電線およびその製造方法について説明する。
本実施形態における多孔質膜被覆電線は、上記多孔質膜によって導体が被覆されている。上述したように、多孔質膜は均一で小さな空孔を有している。多孔質膜は、複数の空孔を有し、空孔率が向上することによって、低誘電率となる。このため、本実施形態における多孔質膜被覆電線は、低誘電率であって、伝送信号の高速化に優れている。さらに、多孔質膜中の空孔がつぶれにくく、外径の変動の少ない電線となっている。
(Porous membrane covered electric wire)
Next, a porous membrane-coated electric wire formed using the above-described water-absorbing fine particles and a method for producing the same will be described.
The porous membrane-covered electric wire in this embodiment is covered with a conductor by the porous membrane. As described above, the porous film has uniform and small pores. The porous film has a plurality of pores, and has a low dielectric constant when the porosity is improved. For this reason, the porous film-coated electric wire in the present embodiment has a low dielectric constant and is excellent in speeding up transmission signals. Furthermore, the pores in the porous film are not easily crushed, and the electric wire has little fluctuation in outer diameter.
上記多孔質膜被覆電線の製造方法について、図を用いて説明する。図２は、本発明の一実施形態にかかる多孔質膜被覆電線の製造方法で用いた製造装置２０の一例を示す概略構成図である。図２に示すように、製造装置２０は、導体送出機２１と、塗布ダイスを備える塗布槽２２と、紫外線ランプを備える紫外線照射装置２３と、乾燥機２４と、電線巻き取り機２５と、を有している。 The manufacturing method of the said porous membrane covering electric wire is demonstrated using figures. FIG. 2 is a schematic configuration diagram illustrating an example of a manufacturing apparatus 20 used in the method for manufacturing a porous membrane-covered electric wire according to an embodiment of the present invention. As shown in FIG. 2, the manufacturing apparatus 20 includes a conductor feeder 21, a coating tank 22 including a coating die, an ultraviolet irradiation device 23 including an ultraviolet lamp, a dryer 24, and a wire winder 25. Have.
本実施形態の多孔質膜被覆電線の製造方法は、吸水性微粒子が分散された紫外線硬化型樹脂前駆体を導体の外周に被覆する工程と、紫外線硬化型樹脂前駆体に紫外線を照射して、絶縁層を形成する工程と、絶縁層を乾燥させ、吸水性微粒子中の水を除去することによって、空孔を形成し、絶縁層を多孔質化する工程と、を含む。 The manufacturing method of the porous membrane-covered electric wire of the present embodiment includes a step of coating the outer periphery of the conductor with an ultraviolet curable resin precursor in which water-absorbing fine particles are dispersed, and irradiating the ultraviolet curable resin precursor with ultraviolet rays. A step of forming an insulating layer; and a step of drying the insulating layer and removing water in the water-absorbing fine particles to form pores and making the insulating layer porous.
まず、上述した多孔質膜の製造方法と同様にして、吸水膨潤状態の吸水性微粒子が分散された、液状の紫外線硬化型樹脂前駆体を調整する。上述したように、吸水性微粒子は、吸水性微粒子を構成する組成物重量の１０倍重量以上の水を吸水し、十分に膨潤状態となっている。この吸水性微粒子は、形成後にさらに水を吸水させる必要がない。また、重合後に吸水したとしても、吸水量が少量であり、吸水による粒子径の増加が少ないので、粉砕工程を必要としない。このため、本実施形態の吸水性微粒子は、そのまま紫外線硬化型樹脂前駆体に分散させ、使用することができる。 First, a liquid ultraviolet curable resin precursor in which water-absorbing fine particles in a water-absorbing and swollen state are dispersed is prepared in the same manner as the above-described porous membrane manufacturing method. As described above, the water-absorbing fine particles absorb water at least 10 times the weight of the composition constituting the water-absorbing fine particles and are sufficiently swollen. The water-absorbing fine particles do not need to further absorb water after formation. Further, even if water is absorbed after polymerization, the amount of water absorption is small, and the increase in particle diameter due to water absorption is small, so that a pulverization step is not required. For this reason, the water-absorbing fine particles of the present embodiment can be used by being dispersed as they are in the ultraviolet curable resin precursor.
続いて、導体送出機２１から長尺状の導体２を送り出し、塗布ダイスを備える塗布槽２２に送る。この塗布槽２２において、塗布ダイス（図示せず）により、長尺状の導体２の外周に液状の紫外線硬化型樹脂前駆体を塗布して、紫外線硬化型樹脂前駆体被覆電線を形成する。紫外線硬化型樹脂前駆体被覆電線は、導体２の外周に、吸水膨潤状態の吸水性微粒子の分散した紫外線硬化型樹脂前駆体が所定の厚さで塗布されている。 Subsequently, the long conductor 2 is sent out from the conductor feeder 21 and sent to the coating tank 22 equipped with a coating die. In this coating tank 22, a liquid ultraviolet curable resin precursor is applied to the outer periphery of the long conductor 2 by a coating die (not shown) to form an ultraviolet curable resin precursor coated electric wire. In the ultraviolet curable resin precursor-coated electric wire, an ultraviolet curable resin precursor in which water-absorbing fine particles in a water-absorbing and swollen state are dispersed is applied to the outer periphery of the conductor 2 with a predetermined thickness.
続いて、紫外線硬化型樹脂前駆体被覆電線を、紫外線ランプを備える紫外線照射装置２３に導入する。紫外線照射装置２３において、紫外線硬化型樹脂前駆体は、紫外線が照射されて、紫外線硬化型樹脂前駆体が架橋硬化された絶縁層３となる。絶縁層３は、図３（ａ）に示すように、導体２を被覆しており、吸水性微粒子を構成する組成物重量の１０倍重量以上の水を含水した吸水性微粒子４が分散した構造となっている。 Subsequently, the ultraviolet curable resin precursor-coated electric wire is introduced into an ultraviolet irradiation device 23 having an ultraviolet lamp. In the ultraviolet irradiation device 23, the ultraviolet curable resin precursor is irradiated with ultraviolet rays to become the insulating layer 3 in which the ultraviolet curable resin precursor is crosslinked and cured. As shown in FIG. 3 (a), the insulating layer 3 covers the conductor 2 and has a structure in which water-absorbing fine particles 4 containing water at least 10 times the weight of the composition constituting the water-absorbing fine particles are dispersed. It has become.
続いて、絶縁層３の形成された電線（絶縁層被覆電線１´）を乾燥機２４に導入する。乾燥機２４において、絶縁層被覆電線１´は、加熱乾燥されて、吸水性微粒子４中の水分が脱水される。この脱水において、図３（ｂ）に示すように、吸水膨潤状態の吸水性微粒子４の領域が空孔６となる。この空孔６の形成により、絶縁層３は多孔質膜５となり、多孔質膜被覆電線１を得る。そして、形成された多孔質膜被覆電線１は、電線巻取り機２５により巻き取られる。 Subsequently, the electric wire (insulating layer-covered electric wire 1 ′) on which the insulating layer 3 is formed is introduced into the dryer 24. In the dryer 24, the insulating layer-covered electric wire 1 ′ is heat-dried to dehydrate the water in the water-absorbing fine particles 4. In this dehydration, the regions of the water-absorbing fine particles 4 in the water-absorbing and swollen state become pores 6 as shown in FIG. By forming the holes 6, the insulating layer 3 becomes the porous film 5, and the porous film-covered electric wire 1 is obtained. The formed porous membrane-covered electric wire 1 is taken up by the electric wire winder 25.
本実施形態にかかる多孔質膜被覆電線の製造方法によれば、外径変動が少なく、伝送信号の高速化に優れた電線を形成することができる。また、十分に吸水膨潤した状態の吸水性微粒子を用いるため、従来のように市販の吸水性微粒子に吸水させる吸水工程を省略することができる。さらに、吸水性微粒子は、重合時に十分な量の水を吸水させ、十分に膨潤した状態での粒子径が制御されるため、吸水にともなう粒子径の増加が少なく、粉砕工程を省略することができる。 According to the method for manufacturing a porous membrane-coated electric wire according to the present embodiment, it is possible to form an electric wire with less fluctuation in outer diameter and excellent in speeding up transmission signals. Moreover, since the water-absorbing fine particles in a sufficiently water-absorbing state are used, a water absorption step for absorbing water by commercially available water-absorbing fine particles as in the past can be omitted. Furthermore, since the water-absorbing fine particles absorb a sufficient amount of water during polymerization and the particle size in a sufficiently swollen state is controlled, there is little increase in the particle size due to water absorption, and the pulverization step can be omitted. it can.
（実施例１）
以下の方法および条件で、本発明にかかる吸水性微粒子を製造した。
不飽和有機酸としてのアクリル酸(和光純薬社製)１．１３g、不飽和有機酸塩としての
アクリル酸ナトリウム(和光純薬社製)１．３０ｇ、不飽和アミドとしてのアクリルアミド(和光純薬社製)１．９３ｇ、架橋剤としてのＮ，Ｎ’−メチレンビスアクリルアミド(和
光純薬社製)０．５７ｇ、重合開始剤としてのペルオキソ二硫酸アンモニウム(和光純薬社製)０．０７ｇからなる組成物（総重量５．００ｇ）に、組成物の５０倍重量の水２５０
ｇを加え溶解し、水相を調整した。一方、水に不溶な有機溶剤としてのシクロヘキサン５００ｇに、界面活性剤としてのソルビタンモノラウレート（花王株式会社製、レオドールＳＰ−Ｌ１０）１５ｇを添加して、油相を調整した。
続いて、上記水相と油相とを混合し、その混合物をホモジナイザー（（株）日本精機製作所製、エクセルオートＥＤ−１０）により３０００回転／分で５分間攪拌し逆相エマルジョン状態とした。この混合物を、還流冷却基が取り付けられたセパラブルフラスコに入れ、窒素ガスを液中にバブリングさせ、二枚羽式の攪拌機で４００回転/分で攪拌し、水
浴中で６５℃に４時間加温し、重合した。その後、加温、攪拌を停止し、１昼夜静置した。
静置された混合物は２層に分離しており、分離した上層の油相を除去することにより、吸水膨潤状態の吸水性微粒子を得た。
Example 1
Water-absorbing fine particles according to the present invention were produced by the following method and conditions.
1.13 g of acrylic acid as an unsaturated organic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 1.30 g of sodium acrylate as an unsaturated organic acid salt (manufactured by Wako Pure Chemical Industries, Ltd.), acrylamide as an unsaturated amide (Wako Pure Chemical Industries, Ltd.) 1.93 g, 0.57 g of N, N′-methylenebisacrylamide (manufactured by Wako Pure Chemical Industries) as a crosslinking agent, and 0.07 g of ammonium peroxodisulfate (manufactured by Wako Pure Chemical Industries) as a polymerization initiator. To the composition (total weight 5.00 g), 50 times the weight of water 250
g was dissolved to adjust the aqueous phase. On the other hand, to 500 g of cyclohexane as an organic solvent insoluble in water, 15 g of sorbitan monolaurate (manufactured by Kao Corporation, Rhedol SP-L10) as a surfactant was added to adjust the oil phase.
Subsequently, the aqueous phase and the oil phase were mixed, and the mixture was stirred for 5 minutes at 3000 rpm with a homogenizer (manufactured by Nippon Seiki Seisakusho, Excel Auto ED-10) to obtain a reverse phase emulsion state. This mixture was put into a separable flask equipped with a reflux cooling base, nitrogen gas was bubbled into the liquid, stirred at 400 rpm with a two-blade stirrer, and heated at 65 ° C. for 4 hours in a water bath. Warmed and polymerized. Thereafter, heating and stirring were stopped, and the mixture was allowed to stand for one day.
The mixture that was allowed to stand was separated into two layers, and the water phase of the water-absorbing swollen state was obtained by removing the separated upper oil phase.
得られた吸水性微粒子を顕微鏡で観察し、その粒子径を測定した。得られた吸水性微粒子には、粗大な粒子はなく、その粒子径が５〜１５μｍ程度、平均粒子径が１０μｍであった。これらの吸水性微粒子には、添加された水量分（２５０ｇ）の水が含水されている。また、得られた吸水性微粒子が十分に膨潤量の水を含水しているかを確認するため、吸水性微粒子を蒸留水中に一定時間浸水した。浸水前後において、吸水性微粒子の重量および粒子径は変化が確認されなかった。この結果から、実施例１の吸水性微粒子は、十分に膨潤状態まで水を含水しており、吸水膨潤状態での粒子径が５〜１５μｍ程度、平均粒子径が１０μｍであることがわかった。 The obtained water-absorbing fine particles were observed with a microscope, and the particle diameter was measured. The obtained water-absorbing fine particles had no coarse particles, and had a particle size of about 5 to 15 μm and an average particle size of 10 μm. These water-absorbing fine particles contain water corresponding to the amount of water added (250 g). Further, in order to confirm whether or not the obtained water-absorbing fine particles contained a sufficient amount of water, the water-absorbing fine particles were immersed in distilled water for a certain period of time. No change was observed in the weight and particle size of the water-absorbing fine particles before and after the immersion. From this result, it was found that the water-absorbing fine particles of Example 1 sufficiently contained water to the swollen state, the particle size in the water-absorbing swollen state was about 5 to 15 μm, and the average particle size was 10 μm.
（実施例２）
実施例２では、実施例１の水相を構成する組成物の添加量、および、組成物の重量に対する水の重量を変化させただけで、その他の条件については、実施例１と同様にして、吸水性微粒子を製造した。
具体的には、不飽和有機酸としてのアクリル酸１．１３g、不飽和有機酸塩としてのア
クリル酸ナトリウム１．３０ｇ、不飽和アミドとしてのアクリルアミド１．９３ｇ、架橋剤としてのＮ，Ｎ’−メチレンビスアクリルアミド０．５７ｇ、重合開始剤としてのペルオキソ二硫酸アンモニウム０．０７ｇからなる組成物（総重量５．００ｇ）に、組成物の３０倍重量の水１５０ｇを加え溶解し、水相を調整した。
(Example 2)
In Example 2, the amount of the composition constituting the aqueous phase of Example 1 and the weight of water relative to the weight of the composition were changed, and the other conditions were the same as in Example 1. Water-absorbing fine particles were produced.
Specifically, 1.13 g of acrylic acid as an unsaturated organic acid, 1.30 g of sodium acrylate as an unsaturated organic acid salt, 1.93 g of acrylamide as an unsaturated amide, N, N′— as a crosslinking agent To a composition (total weight: 5.00 g) consisting of 0.57 g of methylenebisacrylamide and 0.07 g of ammonium peroxodisulfate as a polymerization initiator, 150 g of water 30 times the weight of the composition was added and dissolved to prepare an aqueous phase. .
実施例１と同様に、実施例２で得られた吸水性微粒子を顕微鏡で観察し、その粒子径を測定した。実施例１と同様に、粗大な粒子はなく、その粒子径は５〜１５μｍ程度、平均粒子径は１０μｍであった。これらの吸水性微粒子には、添加された水量分（１５０ｇ）の水が含水されている。また、実施例１と同様に、実施例２の吸水性微粒子を蒸留水中に一定時間浸水し、十分に膨潤量の水を含水しているかを確認した。浸水させた結果、吸水性微粒子は、浸水の前後で、その全量に対して、さらに１００ｇの水を吸水した。吸水により個々の粒子径に多少の変動が確認されたものの、平均粒子径は１０μｍと変化しなかった。以上から、予め重合時に組成物重量の１０倍重量以上の水で重合することで、膨潤状態となっても平均２０μｍ以下の微細な吸水性微粒子を得られることが分かった。また、微細な粒子径の吸水性微粒子であるため、粉砕工程を設けることなく、多孔質膜の製造に使用できることが分かった。 Similarly to Example 1, the water-absorbing fine particles obtained in Example 2 were observed with a microscope, and the particle diameter was measured. As in Example 1, there were no coarse particles, the particle size was about 5 to 15 μm, and the average particle size was 10 μm. These water-absorbing fine particles contain water corresponding to the amount of water added (150 g). Further, similarly to Example 1, the water-absorbing fine particles of Example 2 were immersed in distilled water for a certain period of time, and it was confirmed whether or not a sufficient amount of water was contained. As a result of the immersion, the water-absorbing fine particles absorbed 100 g of water with respect to the total amount before and after the immersion. Although some variation in individual particle size was confirmed by water absorption, the average particle size did not change to 10 μm. From the above, it has been found that fine water-absorbing fine particles having an average of 20 μm or less can be obtained even in a swollen state by polymerizing with water at least 10 times the weight of the composition at the time of polymerization. Moreover, since it was a water-absorbing fine particle of a fine particle diameter, it turned out that it can be used for manufacture of a porous membrane, without providing a grinding | pulverization process.
（比較例１）
比較例１では、組成物を溶解する水の重量を、組成物重量の２倍重量である１０ｇと変更した点を除いて、実施例１と同様の方法および条件で吸水性微粒子を製造した。
得られた吸水性微粒子は、その粒子径が５〜１５μｍ、平均粒子径が１０μmの大きさ
であった。これらの吸水性微粒子には、添加された水量分（１０ｇ）の水が含水されている。さらに、吸水性微粒子を蒸留水に一定時間浸水させ、取り出した後、この吸水性粒子の重量および粒子径を測定した。吸水性微粒子は、その全量に対して、さらに２４０ｇの水を吸水し、その粒子径が１０〜５０μｍ、平均粒子径が３０μmとなり、浸水前よりも
増加していた。
この結果から、比較例１における吸水性微粒子は、形成された時点では、十分な膨潤量まで水を含水せず、大きな吸水能力を有していたため、浸水により多量の水を吸水し、重合時に制御された粒子径よりも大きくなったものと考えられる。そして、吸水にともなう粒子径の変動により、粒子径が１０〜５０μｍとなり、浸水前よりも粒子径分布が広く、ばらつきが生じた。また、平均粒子径が３０μｍに増加しているため、多孔質膜の製造に用いる場合、粉砕工程を設ける必要性があり、製造工程が複雑になる。さらに、粒子径が疎らになっていることから、吸水性微粒子のそれぞれは、吸水量が異なることがわかった。
(Comparative Example 1)
In Comparative Example 1, water-absorbing fine particles were produced by the same method and conditions as in Example 1 except that the weight of water in which the composition was dissolved was changed to 10 g, which was twice the weight of the composition.
The obtained water-absorbing fine particles had a particle size of 5 to 15 μm and an average particle size of 10 μm. These water-absorbing fine particles contain water corresponding to the added amount of water (10 g). Further, after the water-absorbing fine particles were immersed in distilled water for a certain time and taken out, the weight and particle diameter of the water-absorbing particles were measured. The water-absorbing fine particles absorbed 240 g of water with respect to the total amount of the water-absorbing fine particles, and had a particle size of 10 to 50 μm and an average particle size of 30 μm, which were larger than before water immersion.
From this result, the water-absorbing fine particles in Comparative Example 1 did not contain water up to a sufficient swell amount at the time of formation, and had a large water-absorbing ability. It is considered that the particle size was larger than the controlled particle size. And due to the fluctuation of the particle diameter due to water absorption, the particle diameter became 10 to 50 μm, the particle diameter distribution was wider than before the immersion, and variation occurred. In addition, since the average particle diameter is increased to 30 μm, it is necessary to provide a pulverization step when used for the production of a porous membrane, which complicates the production process. Furthermore, since the particle diameter was sparse, it was found that each of the water-absorbing fine particles had a different amount of water absorption.
（実施例３）
以下の方法および条件で、本発明にかかる多孔質膜を製造した。
オリゴマーとしての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）１００重量部、モノマーとしてのシクロペンタニ
ルアクリレート(FA-513AS、日立化成工業)５５重量部、光開始剤としての１-ヒドロキシ
シクロヘキシルフェニルケトン(IRGACURE 184、チバスペシャリティケミカルズ)３重量部、光重合開始剤としての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、チバスペシャリティケミカルズ)４．５重量部、酸化防止剤として
の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、チバスペシャリティケミカルズ)０．１５重量部、
および安定剤としてのヒドロキノン０．１５重量部を混練機に投入し混練し、紫外線硬化
型樹脂前駆体を調整した。
(Example 3)
A porous membrane according to the present invention was produced by the following method and conditions.
100 parts by weight of H-MDI-modified polyethylene glycol adipate dimethacrylate oligomer (UA-4002HM, Shin-Nakamura Chemical) as an oligomer, 55 parts by weight of cyclopentanyl acrylate (FA-513AS, Hitachi Chemical) as a photoinitiator 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184, Ciba Specialty Chemicals) 3 parts by weight, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (DAROCUR TPO, Ciba Specialty Chemicals) 4.5 parts by weight as a photopolymerization initiator 2,2-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (IRGANOX 1035, Ciba Specialty Chemicals) as an antioxidant,
Then, 0.15 part by weight of hydroquinone as a stabilizer was put into a kneader and kneaded to prepare an ultraviolet curable resin precursor.
上記した液状の紫外線硬化型樹脂前駆体に実施例１で得た吸水性ポリマ微粒子５０重量％加えた組成物をアプリケータで２５℃のガラス板上に塗布し紫外線を照射硬化させ、吸水性微粒子を分散させた紫外線硬化型樹脂膜を形成した。さらに１１０℃で３０分間膜を加熱し、紫外線硬化型樹脂膜の吸水性微粒子中の水を除去することで、吸水性微粒子が点在していた部分は空孔となり、空孔径５〜１５μｍ、平均空孔径１０μｍで、膜厚１００μｍの多孔質膜を得た。この多孔質膜は、空孔の潰れによる外径変動は確認されなかった。 A composition obtained by adding 50% by weight of the water-absorbing polymer fine particles obtained in Example 1 to the above-described liquid ultraviolet-curable resin precursor was applied onto a glass plate at 25 ° C. with an applicator, and was cured by irradiation with ultraviolet rays. An ultraviolet curable resin film in which was dispersed was formed. Further, the film was heated at 110 ° C. for 30 minutes to remove water in the water-absorbing fine particles of the ultraviolet curable resin film, whereby the portions where the water-absorbing fine particles were scattered became pores, and the pore diameter was 5 to 15 μm. A porous film having an average pore diameter of 10 μm and a film thickness of 100 μm was obtained. This porous membrane was not observed to change in outer diameter due to void collapse.
（実施例４）
以下の方法および条件で、本発明にかかる多孔質膜被覆電線を製造した。
実施例３と同様にして、実施例１の吸水性微粒子を液状の紫外線硬化型樹脂前駆体に５０重量％加えた組成物を塗料（ワニス）として、図２に示すような塗布硬化乾燥装置を用いて多孔質膜被覆電線を作製した。
導体送出機により、導体としての２５μｍ径を有する銅撚り線（素線本数７本）を一定の速度で送り出し、塗布槽において、その外周に紫外線硬化型樹脂前駆体を被覆した（厚さ４０μｍ）。そして、紫外線硬化型樹脂前駆体に被覆された撚り線を、紫外線ランプとしてのメタルハライドランプ（１ｋＷ）を備える紫外線照射装置内に導入した。ハライドランプにより紫外線硬化型樹脂前駆体を架橋硬化して、絶縁層を形成した。硬化された絶縁層を有する電線を乾燥機に導入し、２５０℃熱風方式で１秒加熱した。この加熱により、絶縁層に分散した吸水性微粒子中の水分を脱水、除去して、絶縁層を多孔質化した。多孔質化された絶縁層（多孔質膜）を有する電線を電線巻取り機（１００ｍ／分）により巻き取った。
得られた多孔質膜被覆電線は、平均空孔径１０μｍ程度であって、気泡が全多孔質膜の体積中で５０％を有していた。また、多孔質膜被覆電線には、空孔の潰れによる外径変動は確認されなかった。また、多孔質膜被覆電線は、導体が低誘電率の多孔質膜に被覆されるため、信号送信の高速化に優れた電線である。
Example 4
The porous membrane-coated electric wire according to the present invention was manufactured by the following method and conditions.
In the same manner as in Example 3, a coating / drying apparatus as shown in FIG. 2 was prepared using as a paint (varnish) a composition obtained by adding 50% by weight of the water-absorbing fine particles of Example 1 to a liquid UV-curable resin precursor. A porous membrane-coated electric wire was produced using this.
A conductor stranding machine sent out a twisted copper wire having a diameter of 25 μm (number of strands: 7) as a conductor at a constant speed, and in the coating tank, the outer periphery thereof was coated with an ultraviolet curable resin precursor (thickness: 40 μm). . And the strand wire coat | covered with the ultraviolet curable resin precursor was introduce | transduced in the ultraviolet irradiation apparatus provided with the metal halide lamp (1 kW) as an ultraviolet lamp. The ultraviolet curable resin precursor was crosslinked and cured with a halide lamp to form an insulating layer. The electric wire having the cured insulating layer was introduced into a dryer and heated by a hot air method at 250 ° C. for 1 second. By this heating, the water in the water-absorbing fine particles dispersed in the insulating layer was dehydrated and removed to make the insulating layer porous. An electric wire having a porous insulating layer (porous membrane) was wound by an electric wire winder (100 m / min).
The obtained porous membrane-covered electric wire had an average pore diameter of about 10 μm, and bubbles had 50% in the volume of the total porous membrane. Moreover, the outer diameter fluctuation | variation by the crushing of a void | hole was not confirmed by the porous membrane covering electric wire. The porous film-covered electric wire is an electric wire excellent in speeding up signal transmission because the conductor is covered with a porous film having a low dielectric constant.
１ 多孔質膜被覆電線
１´ 絶縁層被覆電線
２ 導体
３ 絶縁層
４ 吸水膨潤状態の吸水性微粒子
５ 多孔質膜
６ 空孔
DESCRIPTION OF SYMBOLS 1 Porous membrane covering electric wire 1 'Insulating layer covering electric wire 2 Conductor 3 Insulating layer 4 Water-absorbing fine particle of a water absorption swelling state 5 Porous membrane 6 Hole
Claims (10)
不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物から重合され、重合の際に、前記組成物重量の１０倍重量以上の水を含水していることを特徴とする吸水性微粒子。 Water-absorbing fine particles in a water-absorbing swollen state absorbed beforehand,
Polymerized from a composition containing an unsaturated organic acid, an unsaturated organic acid salt, an unsaturated amide, a cross-linking agent, and a polymerization initiator, and containing at least 10 times the weight of the composition during the polymerization Water-absorbing fine particles characterized by
不飽和有機酸、不飽和有機酸塩、不飽和アミド、架橋剤、および重合開始剤を含む組成物が前記組成物の重量の１０倍重量以上の水に溶解された水相と、水に不溶な有機溶剤を含む油相と、からなる混合物を攪拌し、油中水滴型のエマルジョンとした状態において、
前記混合物を加熱、重合し、当該加熱重合の際に、前記組成物重量の１０倍重量以上の水を含水させることを特徴とする吸水性微粒子の製造方法。 A method of producing water-absorbing fine particles by a reverse phase suspension polymerization method,
An aqueous phase in which a composition containing an unsaturated organic acid, an unsaturated organic acid salt, an unsaturated amide, a crosslinking agent, and a polymerization initiator is dissolved in water at least 10 times the weight of the composition, and insoluble in water In a state where a mixture comprising an oil phase containing an organic solvent is stirred to form a water-in-oil emulsion,
A method for producing water-absorbing fine particles, characterized in that the mixture is heated and polymerized, and at the time of the heat polymerization, water at least 10 times the weight of the composition is added with water.
前記吸水性微粒子が分散された紫外線硬化型樹脂前駆体に紫外線を照射して、前記紫外線硬化型樹脂前駆体を硬化させ、絶縁層を形成する工程と、
前記絶縁層を乾燥させ、前記吸水性微粒子中の水を除去することによって、空孔を形成し、前記絶縁層を多孔質化する工程と、
を含むことを特徴とする多孔質膜の製造方法。 A method for producing a porous film formed using the water-absorbing fine particles obtained by the production method according to any one of claims 5 to 8,
Irradiating the ultraviolet curable resin precursor in which the water-absorbing fine particles are dispersed with ultraviolet rays, curing the ultraviolet curable resin precursor, and forming an insulating layer;
Drying the insulating layer and removing water in the water-absorbing fine particles to form pores and making the insulating layer porous;
A method for producing a porous membrane, comprising:
前記吸水性微粒子が分散された紫外線硬化型樹脂前駆体を導体の外周に被覆する工程と、
前記導体の外周に被覆された前記紫外線硬化型樹脂前駆体に紫外線を照射し、架橋硬化させて、絶縁層を形成する工程と、
前記絶縁層を乾燥させ、前記吸水性微粒子中の水を除去することによって、空孔を形成し、前記絶縁層を多孔質化する工程と、
を含むことを特徴とする多孔質膜被覆電線の製造方法。 A method for producing a porous membrane-coated electric wire formed using the water-absorbing fine particles obtained by the production method according to any one of claims 5 to 8,
Coating the outer periphery of the conductor with an ultraviolet curable resin precursor in which the water-absorbing fine particles are dispersed;
Irradiating the ultraviolet curable resin precursor coated on the outer periphery of the conductor with ultraviolet rays, crosslinking and curing, and forming an insulating layer;
Drying the insulating layer and removing water in the water-absorbing fine particles to form pores and making the insulating layer porous;
The manufacturing method of the porous membrane-coated electric wire characterized by including.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103965397A (en) * | 2014-04-23 | 2014-08-06 | 杭州电子科技大学 | Preparation method for porous type polyacrylamide macromolecule hygroscopic material |
| JP2018057157A (en) * | 2016-09-29 | 2018-04-05 | 三菱電機エンジニアリング株式会社 | Electric power conversion system |
| CN111466810A (en) * | 2013-10-18 | 2020-07-31 | 赛尔格有限责任公司 | Porous membrane wipes and methods of making and using same |
-
2011
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111466810A (en) * | 2013-10-18 | 2020-07-31 | 赛尔格有限责任公司 | Porous membrane wipes and methods of making and using same |
| CN103965397A (en) * | 2014-04-23 | 2014-08-06 | 杭州电子科技大学 | Preparation method for porous type polyacrylamide macromolecule hygroscopic material |
| JP2018057157A (en) * | 2016-09-29 | 2018-04-05 | 三菱電機エンジニアリング株式会社 | Electric power conversion system |
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