JP2014148774A - Nonwoven fabric and method for producing the same - Google Patents
Nonwoven fabric and method for producing the same Download PDFInfo
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本発明は、保水性、拡散性、吸い上げ高さに優れた不織布と、その製造方法に関する。 The present invention relates to a nonwoven fabric excellent in water retention, diffusibility, and sucking height, and a method for producing the same.
不織布は、一般に紡績工程や撚糸工程を経ることなく繊維から直接製造することができるため、その製造工程は織物や編物に比べて簡単である。このような利点を有する不織布は、衛生材料や日用品などに広く利用されている。この不織布の中でポリプロピレン系不織布は、紙おむつやナプキンの表面材、簡易ワイパー、二次電池用のセパレータ、フィルター（ろ材）など広く用いられている。表面材用途として用いられる際、不織布は高吸収体ポリマーやパルプからなる吸収性シートの上に設置されるが、吸収性シート全面に効率良く液体を拡散させるための拡散性、液体を多く吸収するための保液性、吸収体から不織布への液戻り防止性など、不織布には様々な性能が必要とされている。 Since a nonwoven fabric can generally be manufactured directly from fibers without passing through a spinning process or a twisting process, the manufacturing process is simpler than that of a woven fabric or a knitted fabric. Nonwoven fabrics having such advantages are widely used for sanitary materials and daily necessities. Among these nonwoven fabrics, polypropylene-based nonwoven fabrics are widely used such as paper diapers and napkin surface materials, simple wipers, secondary battery separators, filters (filter media) and the like. When used as a surface material, the nonwoven fabric is placed on an absorbent sheet made of a superabsorbent polymer or pulp, but absorbs a large amount of liquid, diffusibility for efficiently diffusing liquid over the entire surface of the absorbent sheet. Various performances are required for the nonwoven fabric, such as liquid retention for preventing liquid and preventing liquid from returning from the absorbent to the nonwoven fabric.
このような性能を不織布に付与するため様々な試みが報告されてきた。例えば、（１）繊維に脂肪酸グリセリド、アルコキシ化アルキルフェノール、ポリオキシアルキレン脂肪酸エステル群から選ばれた界面活性剤を０．３〜７質量％練りこみ、分割構造を用いて繊維を細分化し液体拡散性を向上させた不織布が提供されている（例えば、特許文献１）。また、（２）ポリエチレンテレフタレートとナイロン６で構成された分割型複合繊維にニードルパンチ加工を施し繊維の細分化をさせ吸収性・拡散性を向上させた不織布が提供されている（例えば、特許文献２）。 Various attempts have been reported to impart such performance to nonwoven fabrics. For example, (1) 0.3 to 7% by mass of a surfactant selected from the group consisting of fatty acid glycerides, alkoxylated alkylphenols and polyoxyalkylene fatty acid esters is kneaded into the fibers, and the fibers are subdivided using a divided structure to be liquid diffusible. A non-woven fabric with improved resistance is provided (for example, Patent Document 1). Further, (2) non-woven fabrics are provided in which split-type composite fibers composed of polyethylene terephthalate and nylon 6 are subjected to needle punching to subdivide the fibers to improve absorbability and diffusibility (for example, Patent Documents). 2).
しかし特許文献１は、例えばエトキシ化アルキルフェノール及び混合グリセリドからなる非イオン界面活性剤等をポリエチレン繊維に添加しウォータージェット加工を用いて細分化させる技術であり、界面活性剤の性能によって拡散性を向上させた技術である。また特許文献２は、例えばポリエチレンテレフタレートとナイロン６で構成された分割型複合繊維にニードルパンチ加工を施し繊維の細分化をさせ吸収性・拡散性を向上させた不織布の技術であり、ポリオレフィン繊維は用いられていない。 However, Patent Document 1 is a technology in which, for example, a nonionic surfactant composed of an ethoxylated alkylphenol and a mixed glyceride is added to polyethylene fiber and subdivided using water jet processing, and the diffusibility is improved by the performance of the surfactant. Technology. Patent Document 2 is a nonwoven fabric technology in which, for example, a split type composite fiber composed of polyethylene terephthalate and nylon 6 is subjected to needle punching to subdivide the fiber to improve absorbability and diffusibility. Not used.
本発明はこのような状況下になされたものであり、保水性、拡散性、吸い上げ高さに優れた不織布及びその製造方法を提供することを目的とする。 The present invention has been made under such circumstances, and an object of the present invention is to provide a nonwoven fabric excellent in water retention, diffusibility, and sucking height, and a method for producing the same.
本発明者らは、前記目的を達成すべく鋭意研究を重ねた結果、熱可塑性樹脂からなり、相互に離隔された少なくとも２区分の高融点成分（Ａ）と、該高融点成分（Ａ）を隔離又は囲繞する、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）とで構成される熱接着性複合繊維からなる基材繊維を熱融着してなる不織布であって、（１）該熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、（２）該低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であり、
（３）該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上であり、かつ（４）該複合繊維を熱融着した不織布において、基材繊維の複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体として該塊状部を貫く繊維状部との二成分の分離構造を呈している、の条件を満足していることを特徴とする不織布とすることによって前記目的を達成できることを見出し、本願発明を完成した。
As a result of intensive studies to achieve the above object, the inventors have made at least two high melting point components (A) made of a thermoplastic resin and separated from each other, and the high melting point component (A). A base fiber made of a heat-adhesive conjugate fiber composed of a low melting point component (B) made of a resin composition containing a crystalline resin (a) and an amorphous resin (b) is isolated or surrounded. A non-woven fabric formed by fusing, wherein (1) the mass ratio of the high melting point component (A) and the low melting point component (B) in the thermoadhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65, (2) the melting point of the crystalline resin (a) of the low melting point component (B) is a temperature below the glass transition point of the amorphous resin (b),
(3) The content of the amorphous resin (b) is 5% by mass or more with respect to the entire heat-adhesive conjugate fiber, and (4) In the nonwoven fabric obtained by heat-sealing the conjugate fiber, The condition that the composite fiber exhibits a two-component separation structure of a massive part formed by agglomeration of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) and penetrating through the massive part. It was found that the object can be achieved by using a nonwoven fabric characterized by satisfying the above, and the present invention has been completed.
すなわち、本発明は、
〔１〕熱可塑性樹脂からなり、相互に離隔された少なくとも２区分の高融点成分（Ａ）と、該高融点成分（Ａ）を隔離又は囲繞する、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）とで構成される熱接着性複合繊維からなる基材繊維を熱融着してなる不織布であって、次の（１）〜（４）の条件を満足していることを特徴とする不織布、
（１）該熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、
（２）該低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であり、
（３）該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上であり、かつ
（４）該複合繊維を熱融着した不織布において、基材繊維の複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体として該塊状部を貫く繊維状部との二成分の分離構造を呈している。
〔２〕基材繊維の熱接着性複合繊維が熱可塑性樹脂からなる高融点成分（Ａ）による２以上の島成分を有する海島構造複合繊維である〔１〕に記載の不織布、
〔３〕基材繊維を単位とする繊維軸方向における前記分離構造において、隣り合う塊状部間の平均長さが１０〜２００μｍである〔１〕又は〔２〕に記載の不織布、
〔４〕基材繊維を単位とする繊維軸方向における前記分離構造において、前記塊状部を貫く繊維状部の複数本の繊維間の平均長さが３〜１０μｍである〔１〕〜〔３〕のいずれかに記載の不織布、
〔５〕高融点成分（Ａ）の熱可塑性樹脂が結晶性ポリプロピレンまたはポリエチレンテレフタレートであり、低融点成分（Ｂ）の結晶性樹脂（ａ）が高密度ポリエチレンである〔１〕〜〔４〕のいずれかに記載の不織布、
〔６〕低融点成分（Ｂ）の非晶性樹脂（ｂ）が環状オレフィンコポリマー及び／又はポリカーボネートである〔１〕〜〔５〕のいずれかに記載の不織布、
〔７〕熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、該低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であり、かつ該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上である原料組成物を、熱可塑性樹脂からなり相互に離隔された少なくとも２区分の高融点成分（Ａ）と、該高融点成分（Ａ）を隔離又は囲繞する、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）とで構成される熱接着性複合繊維として溶融紡糸する工程、これを所定の倍率で延伸する工程、さらに捲縮付与、油剤付着、及び短繊維に切断する工程を経て得られた基材繊維としての熱接着性複合繊維を、常法によりウェブの集積体とする工程及び絡合工程、さらに低融点成分（Ｂ）の結晶性樹脂（ａ）の融点以上の温度による熱融着工程を経て不織布を製造する方法であって、
該熱融着工程を、低融点成分（Ｂ）の結晶性樹脂（ａ）の融点以上であり、かつ非晶性樹脂（ｂ）のガラス転移点以下の温度で行うことによって、基材繊維としての複合繊維に、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部とに分離した構造を発現させることを特徴とする不織布の製造方法、及び
〔８〕〔１〕〜〔６〕のいずれかに記載の不織布を表面布に用いてなることを特徴とする衛生材料、
を提供するものである。
That is, the present invention
[1] At least two high-melting-point components (A) that are made of a thermoplastic resin and are separated from each other, and the crystalline resin (a) and the amorphous resin that isolate or surround the high-melting-point components (A) (B) is a non-woven fabric obtained by heat-sealing a base fiber made of a heat-adhesive conjugate fiber composed of a low-melting-point component (B) made of a resin composition comprising the following (1) to A non-woven fabric characterized by satisfying the condition of (4),
(1) The mass ratio of the high melting point component (A) and the low melting point component (B) in the thermoadhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65. ,
(2) The melting point of the crystalline resin (a) of the low melting point component (B) is a temperature below the glass transition point of the amorphous resin (b),
(3) The content of the amorphous resin (b) is 5% by mass or more with respect to the entire heat-adhesive conjugate fiber, and (4) In the nonwoven fabric obtained by heat-sealing the conjugate fiber, The composite fiber has a two-component separation structure of a massive part formed by aggregation of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) and penetrating through the massive part.
[2] The non-woven fabric according to [1], wherein the heat-adhesive conjugate fiber of the base fiber is a sea-island structure conjugate fiber having two or more island components by a high melting point component (A) made of a thermoplastic resin.
[3] The nonwoven fabric according to [1] or [2], wherein an average length between adjacent massive portions is 10 to 200 μm in the separation structure in the fiber axis direction in which the base fiber is a unit.
[4] In the separation structure in the fiber axis direction in which the base fiber is a unit, the average length between a plurality of fibers of the fibrous portion penetrating the massive portion is 3 to 10 μm [1] to [3] Nonwoven fabric according to any one of
[5] The high melting point component (A) thermoplastic resin is crystalline polypropylene or polyethylene terephthalate, and the low melting point component (B) crystalline resin (a) is high density polyethylene. The nonwoven fabric according to any one of the above,
[6] The nonwoven fabric according to any one of [1] to [5], wherein the amorphous resin (b) of the low melting point component (B) is a cyclic olefin copolymer and / or polycarbonate.
[7] The mass ratio of the high melting point component (A) and the low melting point component (B) in the thermoadhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65, The melting point of the crystalline resin (a) of the low melting point component (B) is a temperature not higher than the glass transition point of the amorphous resin (b), and the content of the amorphous resin (b) is thermal adhesiveness. The raw material composition of 5% by mass or more with respect to the entire composite fiber is separated from at least two high melting point components (A) made of thermoplastic resin and separated from each other, or the high melting point component (A). A step of melt spinning as a heat-adhesive conjugate fiber composed of a low melting point component (B) made of a resin composition containing a crystalline resin (a) and an amorphous resin (b), It was obtained through a step of stretching at a magnification of 1, a step of crimping, adhesion of an oil agent, and a step of cutting into short fibers. The process of making the heat-adhesive conjugate fiber as a material fiber into a web aggregate by a conventional method, and the thermal fusion process at a temperature equal to or higher than the melting point of the crystalline resin (a) of the low melting point component (B) Through which a nonwoven fabric is produced,
By performing the thermal fusion process at a temperature not lower than the melting point of the crystalline resin (a) of the low melting point component (B) and not higher than the glass transition point of the amorphous resin (b), The composite fiber is made to exhibit a structure in which the low melting point component (B) is agglomerated and the high melting point component (A) as a main component and separated into a fibrous part penetrating between the bulk parts. And a sanitary material characterized in that the nonwoven fabric according to any one of [8] [1] to [6] is used as a surface cloth,
Is to provide.
本発明によれば、保水性、拡散性、吸い上げ高さに優れた不織布を提供することができる。
本発明の不織布は、該不織布を構成する基材繊維としての複合繊維に、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部とに分離した構造を持つため、塊状部間の平均長さ（間隔）が１０〜２００μｍで、繊維状部の複数本の繊維間の平均長さ（間隙）が３〜１０μｍの微細な空間が形成される。この空間に液体が保持され、高い保水性を発揮する。またこの形状により強い毛細管現象が働くため、高い拡散性、吸い上げ高さを発揮する。これにより、紙おむつやナプキンの表面材や、最近の紙おむつの３構造（吸収体／セカンドシート／トップシート）においてセカンドシート用途として用いれば高い保水性、拡散性、耐久親水性を発揮できる。また、本発明の不織布は吸い上げ高さが向上する。
According to the present invention, it is possible to provide a nonwoven fabric excellent in water retention, diffusibility, and sucking height.
The nonwoven fabric of the present invention is mainly composed of a mass part formed by agglomeration of the low melting point component (B) and the high melting point component (A) in the composite fiber as the base fiber constituting the nonwoven fabric, and the space between the mass parts is between Since it has a structure separated into the fibrous part that penetrates, the average length (interval) between the massive parts is 10 to 200 μm, and the average length (gap) between the multiple fibers of the fibrous part is 3 to 10 μm A fine space is formed. Liquid is held in this space and exhibits high water retention. In addition, this shape exerts a strong capillary phenomenon, so it exhibits high diffusivity and suction height. Thereby, if it is used as a second sheet application in the surface material of a paper diaper or napkin and the three structures of a recent paper diaper (absorber / second sheet / top sheet), high water retention, diffusibility and durable hydrophilicity can be exhibited. Moreover, the non-woven fabric of the present invention improves the sucking height.
本発明の不織布は、先ず、熱可塑性樹脂からなり、相互に離隔された少なくとも２区分の高融点成分（Ａ）と、該高融点成分（Ａ）を隔離又は囲繞する、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）とで構成される熱接着性複合繊維からなる基材繊維を熱融着してなり、さらに（１）〜（４）の４つ特定の要件を満足する不織布である。その要件のうち、特に、（４）該不織布を構成する基材繊維としての複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部との二成分の分離構造を呈する熱融着不織布であることが形態的な特徴として挙げられる。 The nonwoven fabric of the present invention is first made of a thermoplastic resin, and is separated from or surrounds the high melting point component (A) of at least two sections separated from each other, and the crystalline resin (a). And a base fiber made of a heat-adhesive conjugate fiber composed of a low-melting-point component (B) made of a resin composition containing a non-crystalline resin (b), and (1) to The nonwoven fabric satisfies the four specific requirements of (4). Among the requirements, in particular, (4) the composite fiber as the base fiber constituting the nonwoven fabric is mainly composed of the mass part formed by aggregation of the low melting point component (B) and the high melting point component (A), It is mentioned as a morphological feature that it is a heat-sealing nonwoven fabric exhibiting a two-component separation structure with a fibrous portion penetrating between the massive portions.
本発明において、「相互に離隔された少なくとも２区分の高融点成分（Ａ）」とは、繊維軸方向に直交する熱接着性複合繊維断面において、少なくとも２区分の高融点成分（Ａ）の島或いは区画を有していることを意味する。一方、「該高融点成分（Ａ）を隔離又は囲繞する・・・低融点成分（Ｂ）」とは、熱接着性複合繊維断面において、区画或いは島を構成している少なくとも２区分のそれぞれの高融点成分（Ａ）を低融点成分（Ｂ）で隔離するか、囲繞すなわち周囲を包囲していることを意味する。これらの熱接着性複合繊維断面の形状は、熱融着不織布を構成する以前の基材繊維としての接着性複合繊維に関するものである。
すなわち、本発明の二成分の分離構造を発現できる基材繊維としての複合繊維の断面形状は、少なくとも２区分の高融点成分（Ａ）を有する繊維であれば、図１（ｉ）に断面を示すような海島型複合繊維構造に限らず、分割繊維構造であってもよい。また、複合繊維の断面形状は円形でなくてもよく、矩形でもよく、また楕円形、或いは星型、十字型等の異型断面であってもよい。島成分の断面形状も同様に異型断面であってもよい。
そして、本発明の不織布は、以下の要件を満足せねばならない。
In the present invention, “at least two sections of the high melting point component (A) separated from each other” means an island of at least two sections of the high melting point component (A) in the cross section of the thermally adhesive composite fiber orthogonal to the fiber axis direction. Or it means having a section. On the other hand, “isolating or surrounding the high melting point component (A)... Low melting point component (B)” means each of at least two sections constituting a section or an island in the cross section of the thermal adhesive composite fiber. It means that the high melting point component (A) is isolated by the low melting point component (B) or surrounds the surroundings. The shape of the cross section of these heat-adhesive conjugate fibers relates to the adhesive conjugate fibers as the base fiber before constituting the heat-bonding nonwoven fabric.
That is, if the cross-sectional shape of the composite fiber as the base fiber capable of expressing the two-component separation structure of the present invention is a fiber having at least two high melting point components (A), the cross section is shown in FIG. Not only the sea-island type composite fiber structure as shown, but a split fiber structure may be used. Further, the cross-sectional shape of the composite fiber may not be circular, may be rectangular, may be elliptical, or may be an odd-shaped cross section such as a star shape or a cross shape. Similarly, the cross-sectional shape of the island component may be an irregular cross-section.
And the nonwoven fabric of this invention must satisfy the following requirements.
要件（１）：熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であることを要する。
高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５の範囲であれば、熱融着により十分な機械物性を有する不織布を得ることができる。
Requirement (1): The mass ratio of the high melting point component (A) and the low melting point component (B) in the thermoadhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65. It needs to be.
If the mass ratio of the high melting point component (A) and the low melting point component (B) is in the range of the high melting point component (A) / the low melting point component (B) = 45/55 to 35/65, the heat fusion is sufficient. A nonwoven fabric having mechanical properties can be obtained.
要件（２）：低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であることを要する。
結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点と同じ又は以上の温度であれば、不織布を熱融着処理する際の結晶性樹脂（ａ）の融点以上の温度において、非晶性樹脂（ｂ）も融解挙動を呈するので、低融点成分（Ｂ）としての凝集が起こらず、塊状部を形成し得ないので、要件（４）の特異な繊維構造が発現できない。
Requirement (2): It is necessary that the melting point of the crystalline resin (a) of the low melting point component (B) is a temperature lower than the glass transition point of the amorphous resin (b).
If the melting point of the crystalline resin (a) is equal to or higher than the glass transition point of the amorphous resin (b), it is higher than the melting point of the crystalline resin (a) when the non-woven fabric is heat-sealed. Since the amorphous resin (b) also exhibits melting behavior at temperature, the low melting point component (B) does not agglomerate and cannot form a lump, so that a unique fiber structure of the requirement (4) appears. Can not.
要件（３）：非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上であることを要する。
非晶性樹脂（ｂ）の含有率が、熱接着性複合繊維全体に対して５質量％未満では、要件（４）の特異な繊維構造が発現できない。一方、非晶性樹脂（ｂ）の含有率の上限は、特に限定されないが、経済性の観点から概ね１５質量％以下である。
Requirement (3): The content of the amorphous resin (b) is required to be 5% by mass or more with respect to the entire heat-adhesive conjugate fiber.
When the content of the amorphous resin (b) is less than 5% by mass with respect to the whole heat-adhesive conjugate fiber, the specific fiber structure of the requirement (4) cannot be expressed. On the other hand, the upper limit of the content of the amorphous resin (b) is not particularly limited, but is approximately 15% by mass or less from the viewpoint of economy.
要件（４）：複合繊維を熱融着した不織布において、基材繊維の複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体として該塊状部を貫く繊維状部との二成分の分離構造を呈していることを要件とする。
本発明の要件（４）において、「低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部との二成分の分離構造」とは、図２（Ａ）により４本の島部を有する海島構造複合繊維を基材繊維とした場合を説明するならば、不織布の熱融着時に海島型複合繊維の低融点成分（Ｂ）が分離凝集して塊状部２を形成し、高融点成分（Ａ）を主体として該塊状部を貫く４本の島部が繊維状部３を形成し、低融点成分（Ｂ）の凝集部２と高融点成分（Ａ）の繊維状部３との二成分に分離した構造を意味する。この二成分の分離構造は低融点成分（Ｂ）に配合された非晶性樹脂（ｂ）が核となり、不織布化するときの熱融着温度によって発現する。なお本発明の二成分の分離構造を発現できる基材繊維としての複合繊維の断面形状は、少なくとも２区分の高融点成分（Ａ）を有する繊維であれば、前述のように海島型複合繊維構造に限らず、分割繊維構造であってもよい。
Requirement (4): In a nonwoven fabric obtained by heat-bonding a composite fiber, the composite fiber of the base fiber is composed of a lump part formed by aggregation of the low melting point component (B) and the lump part mainly composed of the high melting point component (A). It is a requirement that it has a two-component separation structure with a fibrous part penetrating through the.
In the requirement (4) of the present invention, “separation of two components between a lump part formed by aggregation of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) and penetrating between the lump parts. The structure is a low melting point component of the sea-island type composite fiber when the nonwoven fabric is heat-sealed. B) separates and aggregates to form a lump portion 2, and four island portions penetrating through the lump portion mainly comprising the high melting point component (A) form a fibrous portion 3, and the low melting point component (B) is agglomerated. It means a structure separated into two components of the part 2 and the fibrous part 3 of the high melting point component (A). This two-component separation structure is manifested by the heat-sealing temperature when the non-woven fabric is formed by the amorphous resin (b) blended with the low melting point component (B). In addition, as long as the cross-sectional shape of the composite fiber as the base fiber capable of expressing the two-component separation structure of the present invention is a fiber having at least two high melting point components (A), the sea-island type composite fiber structure is used as described above. Not limited to this, a split fiber structure may be used.
［高融点成分（Ａ）を構成する材料］
本発明の高融点成分（Ａ）を構成する材料としては、熱可塑性樹脂が用いられる。
該熱可塑性樹脂は、その融点が低融点成分（Ｂ）の結晶性樹脂（ａ）の融点よりも高いことを要し、例えば結晶性ポリプロピレン、ポリエチレンテレフタレートやポリブチレンテレフタレートなどの結晶性ポリエステル、ポリアミド（ナイロン）、芳香族ポリエステル樹脂（液晶ポリマー）などを用いることができ、これらは１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。これらの中で、結晶性ポリプロピレン、ポリエチレンテレフタレートが好ましく、融点が比較的低く、加工性、及びコスト的に優れる、結晶性ポリプロピレンが特に好ましい。
[Material constituting high melting point component (A)]
As the material constituting the high melting point component (A) of the present invention, a thermoplastic resin is used.
The thermoplastic resin needs to have a melting point higher than that of the crystalline resin (a) of the low melting point component (B). For example, crystalline polyester, crystalline polyester such as polyethylene terephthalate and polybutylene terephthalate, polyamide (Nylon), aromatic polyester resin (liquid crystal polymer), etc. can be used, and these may be used alone or in combination of two or more. Among these, crystalline polypropylene and polyethylene terephthalate are preferable, and crystalline polypropylene having a relatively low melting point and excellent workability and cost is particularly preferable.
この結晶性ポリプロピレンとしては、アイソタクチックポリプロピレン系樹脂が好ましく用いられる。中でもアイソタクチックペンタッド分率（ＩＰＦ）が、好ましくは８５％以上、より好ましくは９０％以上のものが有利である。また分子量分布の指標であるＱ値（重量平均分子量／数平均分子量Ｍｗ／Ｍｎ比）は６以下、メルトフローレイト（ＭＦＲ）（温度２３０℃、荷重２．１６ｋｇ）は３〜１００ｇ／１０分の範囲が好ましい。上記ＩＰＦが８５％未満では立体規則性が不充分で結晶性が低く、得られる繊維における強度などの物性が劣る。 As this crystalline polypropylene, an isotactic polypropylene resin is preferably used. Among them, those having an isotactic pentad fraction (IPF) of preferably 85% or more, more preferably 90% or more are advantageous. The Q value (weight average molecular weight / number average molecular weight Mw / Mn ratio), which is an index of molecular weight distribution, is 6 or less, and the melt flow rate (MFR) (temperature 230 ° C., load 2.16 kg) is 3 to 100 g / 10 min. A range is preferred. If the IPF is less than 85%, the stereoregularity is insufficient and the crystallinity is low, and the physical properties such as strength of the resulting fiber are poor.
なお、アイソタクチックペンタッド分率（ＩＰＦ）（一般にｍｍｍｍ分率ともいわれる）は、任意の連続する５つのプロピレン単位で構成される炭素−炭素結合による主鎖に対して、側鎖である５つのメチル基がいずれも同方向に位置する立体構造の割合を示すものであって、同位体炭素核磁気共鳴スペクトル（13Ｃ−ＮＭＲ）にけるＰｍｍｍｍ（プロピレン単位が５個連続してアイソタクチック結合した部位における第３単位目のメチル基に由来する吸収強度）およびＰｗ（プロピレン単位の全メチル基に由来する吸収強度）から、下記式
ＩＰＦ（％）＝（Ｐｍｍｍｍ／Ｐｗ）×１００
によって求めることができる。
The isotactic pentad fraction (IPF) (generally also referred to as mmmm fraction) is a side chain with respect to the main chain of carbon-carbon bonds composed of any five consecutive propylene units. This shows the proportion of the three-dimensional structure in which two methyl groups are located in the same direction. Pmmmm (5 propylene units are isotactic) in the isotope carbon nuclear magnetic resonance spectrum ( 13 C-NMR). From the following formula: IPF (%) = (Pmmmm / Pw) × 100 from the absorption intensity derived from the methyl group of the third unit at the bonded site and Pw (absorption intensity derived from all methyl groups of the propylene unit)
Can be obtained.
またこのポリプロピレンはプロピレンの単独重合体であってもよいし、プロピレンとα−オレフィン（例えばエチレン、ブテン−１など）との共重合体であってもよい。
すなわち、結晶性ポリプロピレンとしては、例えば結晶性を有するアイソタクチックプロピレン単独重合体、エチレン単位の含有量の少ないエチレン−プロピレンランダム共重合体、プロピレン単独重合体からなるホモ部とエチレン単位の含有量の比較的多いエチレン−プロピレンランダム共重合体からなる共重合部とから構成されたプロピレンブロック共重合体、さらに前記プロピレンブロック共重合体における各ホモ部または共重合部が、さらにブテン−１などのα−オレフィンを共重合したものからなる結晶性プロピレン−エチレン−α−オレフィン共重合体などが挙げられる。
なお、本発明においては、前記の低融点成分（Ｂ）の材料である樹脂組成物及び高融点成分（Ａ）材料である熱可塑性樹脂には、必要に応じ、各種添加剤、例えば耐候剤、耐熱安定剤、難燃剤、着色剤、消臭剤、抗菌剤、芳香剤などを含有させることができる。
The polypropylene may be a homopolymer of propylene or a copolymer of propylene and an α-olefin (for example, ethylene, butene-1).
That is, as crystalline polypropylene, for example, isotactic propylene homopolymer having crystallinity, ethylene-propylene random copolymer having a small ethylene unit content, homo-part consisting of propylene homopolymer and ethylene unit content A propylene block copolymer composed of a copolymer part composed of an ethylene-propylene random copolymer having a relatively large amount of each of the above-mentioned propylene block copolymers, and each homo part or copolymer part in the propylene block copolymer further includes butene-1, etc. Examples thereof include crystalline propylene-ethylene-α-olefin copolymers formed by copolymerizing α-olefins.
In the present invention, the resin composition that is the material of the low-melting-point component (B) and the thermoplastic resin that is the material of the high-melting-point component (A) include various additives such as a weathering agent, if necessary. Heat stabilizers, flame retardants, colorants, deodorants, antibacterial agents, fragrances, and the like can be included.
［低融点成分（Ｂ）を構成する材料］
本発明の低融点成分（Ｂ）を構成する材料として、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを併用してなる樹脂組成物が用いられる。
（結晶性樹脂（ａ））
低融点成分（Ｂ）の一成分として用いられる結晶性樹脂（ａ）は、その融点が、高融点成分（Ａ）を構成する材料として用いられる熱可塑性樹脂の融点よりも低いことを要する。結晶性樹脂（ａ）の融点が上記条件を満たさない場合、熱接着性を有する繊維が得られにくく、熱風融着法による不織布の作製が困難となる。
該結晶性樹脂（ａ）としては、前述した性状を有するものであればよく、特に制限されず、例えば高密度、中密度、低密度ポリエチレンや直鎖状低密度ポリエチレンなどのエチレン系重合体、プロピレンと他のα−オレフィンとの共重合体、具体的にはプロピレン−ブテン−１ランダム共重合体、プロピレン−エチレン−ブテン−１ランダム共重合体、あるいは軟質ポリプロピレンなどの非結晶性プロピレン系重合体、ポリ４−メチルペンテン−１などを挙げることができる。これらの結晶性樹脂（ａ）は、１種を単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
これらの中で、曳糸（紡糸）性やコストなどを考慮すると高密度ポリエチレン（融点：１３０℃）が好適である。また高密度ポリエチレンのメルトフローレイト（ＭＦＲ）（温度１９０℃、荷重２．１６ｋｇ）は３〜６０ｇ／１０分の範囲が紡糸性や延伸性等の観点から好ましい。
[Material constituting low melting point component (B)]
As a material constituting the low melting point component (B) of the present invention, a resin composition comprising a combination of the crystalline resin (a) and the amorphous resin (b) is used.
(Crystalline resin (a))
The crystalline resin (a) used as one component of the low melting point component (B) needs to have a melting point lower than the melting point of the thermoplastic resin used as the material constituting the high melting point component (A). When the melting point of the crystalline resin (a) does not satisfy the above conditions, it is difficult to obtain a fiber having thermal adhesiveness, and it becomes difficult to produce a nonwoven fabric by a hot air fusion method.
The crystalline resin (a) is not particularly limited as long as it has the properties described above, and examples thereof include ethylene polymers such as high density, medium density, low density polyethylene and linear low density polyethylene, A copolymer of propylene and another α-olefin, specifically, a non-crystalline propylene-based heavy polymer such as propylene-butene-1 random copolymer, propylene-ethylene-butene-1 random copolymer, or soft polypropylene. Examples thereof include polymer and poly-4-methylpentene-1. These crystalline resins (a) may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, high-density polyethylene (melting point: 130 ° C.) is preferable in consideration of the spinnability and cost. The melt flow rate (MFR) (temperature 190 ° C., load 2.16 kg) of high-density polyethylene is preferably in the range of 3 to 60 g / 10 minutes from the viewpoint of spinnability, stretchability, and the like.
（非晶性樹脂（ｂ））
低融点成分（Ｂ）の成分として、前述の結晶性樹脂（ａ）と併用される非晶性樹脂（ｂ）は、非晶性樹脂（ｂ）のガラス転移温度が延伸温度より高い熱的特性を有していることを要する。その理由は、低融点成分（Ｂ）における結晶性樹脂（ａ）と非晶性樹脂（ｂ）との該延伸温度における延伸性の違いにより、非晶性樹脂（ｂ）を核として、高融点成分（Ａ）から剥離させつつ低融点成分（Ｂ）を凝集してなる塊状部を形成させるためである。
該非晶性樹脂（ｂ）としては、環状オレフィン系重合体やポリカーボネートなどを挙げることができる。
環状オレフィン系重合体としては、例えばエチレンとノルボルネンとの共重合体である環状オレフィンコポリマー［ポリプラスチックス社製、登録商標「ＴＯＰＡＳ」、５０１３のＴｇ＝１３４℃］、エチレンと環状オレフィンとの共重合体である環状オレフィンコポリマー［三井化学社製、登録商標「アペル」、ＡＰＬ５０１４ＤＰのＴｇ＝１３５℃］、ノルボルネン誘導体のメタセシス開環重合により得られたシクロオレフィンポリマー［日本ゼオン社製、登録商標「ＺＥＯＮＥＸ」、４８０ＲのＴｇ＝１３８℃］、トリシクロデカン構造を有するシクロオレフィンポリマー［ＪＳＲ社製、登録商標「ＡＲＴＯＮ」、Ｔｇ＝１７１℃］などを挙げることができる。
本発明においては、前記非晶性樹脂（ｂ）は、１種を単独で用いてもよく、２種以上を組み合わせて用いてもよいが、特に環状オレフィンコポリマー及び／又はポリカーボネートが性能の観点から好ましい。
(Amorphous resin (b))
As the component of the low melting point component (B), the amorphous resin (b) used in combination with the above-described crystalline resin (a) has a thermal characteristic in which the glass transition temperature of the amorphous resin (b) is higher than the stretching temperature. It is necessary to have. The reason is that the crystalline resin (a) and the amorphous resin (b) in the low melting point component (B) have a high melting point with the amorphous resin (b) as a core due to the difference in stretchability at the stretching temperature. This is because a lump part formed by aggregating the low-melting-point component (B) while being peeled from the component (A) is formed.
Examples of the amorphous resin (b) include cyclic olefin polymers and polycarbonate.
Examples of the cyclic olefin polymer include a cyclic olefin copolymer that is a copolymer of ethylene and norbornene [manufactured by Polyplastics Co., Ltd., registered trademark “TOPAS”, Tg of 5013 = 134 ° C.], a copolymer of ethylene and cyclic olefin. Cyclic olefin copolymer as a polymer [Mitsui Chemicals, registered trademark “Apel”, APL5014DP Tg = 135 ° C.], cycloolefin polymer obtained by metathesis ring-opening polymerization of norbornene derivative [manufactured by Nippon Zeon, registered trademark “ ZEONEX ”, Tg of 480R = 138 ° C.], cycloolefin polymer having a tricyclodecane structure [manufactured by JSR, registered trademark“ ARTON ”, Tg = 171 ° C.] and the like.
In the present invention, the amorphous resin (b) may be used singly or may be used in combination of two or more, and in particular, a cyclic olefin copolymer and / or polycarbonate is used from the viewpoint of performance. preferable.
なお、非晶性樹脂（ｂ）として環状オレフィン共重合体を用いる場合は、環状オレフィン共重合体の流動性、即ち溶融粘度の指標としては、一般的にメルトボリュームレイト（ＭＶＲ）が用いられているので、本発明の低融点成分（Ｂ）の非晶性樹脂（ｂ）としては、溶融紡糸安定、延伸性の観点から、ＭＶＲが試験法ＩＳＯ １１３３準拠、測定条件：２６０℃、２．１６ｋｇにおいて１０ｍｌ／１０分以上が好ましく、１４ｍｌ／１０分以上がより好ましい。なお、流動性の指標であるＭＶＲは、例えばエチレン単位とノルボルネン単位を含むエチレン・ノルボルネン共重合体を環状オレフィン共重合体として選択するときは、エチレン単位の重合度Ｘ、ノルボルネン単位の重合度Ｙに基づく分子量及び環状オレフィン共重合体全体の分子量分布により、調節されたものから採択することができる。 When a cyclic olefin copolymer is used as the amorphous resin (b), melt volume rate (MVR) is generally used as an index of fluidity of the cyclic olefin copolymer, that is, melt viscosity. Therefore, as the amorphous resin (b) of the low melting point component (B) of the present invention, from the viewpoints of melt spinning stability and stretchability, MVR conforms to test method ISO 1133, measurement conditions: 260 ° C., 2.16 kg. Is preferably 10 ml / 10 minutes or more, more preferably 14 ml / 10 minutes or more. The MVR, which is an index of fluidity, is, for example, when an ethylene / norbornene copolymer containing an ethylene unit and a norbornene unit is selected as the cyclic olefin copolymer, the polymerization degree X of the ethylene unit and the polymerization degree Y of the norbornene unit. The molecular weight based on the above and the molecular weight distribution of the whole cyclic olefin copolymer can be selected from those regulated.
本発明において、低融点成分（Ｂ）材料として用いられる結晶性樹脂（ａ）と非晶性樹脂（ｂ）との含有割合は、質量比で９７：３〜８０：２０であることが好ましく、９５:５〜８５:１５であることがより好ましい。
また、要件（１）該熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、かつ
要件（３）該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上の条件を満足することに配慮する必要がある。
In the present invention, the content ratio of the crystalline resin (a) and the amorphous resin (b) used as the low melting point component (B) material is preferably 97: 3 to 80:20 by mass ratio, More preferably, it is 95: 5-85: 15.
Further, requirement (1) The mass ratio of the high melting point component (A) and the low melting point component (B) in the heat-adhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35 / 65 and requirement (3) It is necessary to consider that the content of the amorphous resin (b) satisfies the condition of 5% by mass or more with respect to the whole heat-adhesive conjugate fiber.
［熱接着性複合繊維の製造方法］
本発明の不織布の基材繊維として用いられる熱接着性複合繊維は、高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、該低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であり、かつ該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上である原料組成物を、熱可塑性樹脂からなり相互に離隔された少なくとも２区分の高融点成分（Ａ）と、該高融点成分（Ａ）を隔離又は囲繞する、結晶性樹脂（ａ）と非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）とで構成される熱接着性複合繊維として溶融紡糸する工程、これを所定の倍率で延伸する工程、さらに捲縮付与、油剤付着、及び短繊維に切断する工程を経て製造することができる。
本発明の不織布の基材繊維としての熱接着性複合繊維のより具体的な製造方法としては、前記表現において「高融点成分（Ａ）を囲繞する・・・低融点成分（Ｂ）」と表現した、いわゆる海島構造繊維に該当する製造方法として、熱可塑性樹脂を含む高融点成分（Ａ）と、高融点成分（Ａ）よりも低い融点を有するポリオレフィン系樹脂（ａ）と延伸温度よりも高いガラス転移点を有する非晶性樹脂（ｂ）とを含む樹脂組成物からなる低融点成分（Ｂ）を少なくとも２つ以上の海島構造に配置した未延伸複合繊維を溶融紡糸する工程、該未延伸複合繊維を結晶性系樹脂（ａ）のＴｇ以上、融点以下の温度であって、かつ非晶性樹脂（ｂ）のＴｇ以下の温度で熱延伸する工程、を経る製造方法によれば、効率よく製造することができる。
[Method for producing heat-adhesive conjugate fiber]
In the heat-adhesive conjugate fiber used as the base fiber of the nonwoven fabric of the present invention, the mass ratio of the high melting point component (A) and the low melting point component (B) is high melting point component (A) / low melting point component (B) = 45. / 55 to 35/65, the melting point of the crystalline resin (a) of the low melting point component (B) is a temperature not higher than the glass transition point of the amorphous resin (b), and the amorphous resin ( The raw material composition whose content of b) is 5% by mass or more with respect to the whole heat-adhesive conjugate fiber is composed of a thermoplastic resin and at least two high-melting-point components (A) separated from each other, A heat-adhesive conjugate fiber composed of a low-melting-point component (B) made of a resin composition containing a crystalline resin (a) and an amorphous resin (b) that isolates or surrounds the high-melting-point component (A) A melt spinning process, a stretching process at a predetermined magnification, crimping, oil adhesion, and short fiber It can be manufactured through a step of cutting the.
As a more specific production method of the heat-adhesive conjugate fiber as the base fiber of the nonwoven fabric of the present invention, the expression “encloses the high melting point component (A) ... low melting point component (B)” in the above expression. As a production method corresponding to so-called sea-island structure fibers, a high melting point component (A) containing a thermoplastic resin, a polyolefin resin (a) having a melting point lower than that of the high melting point component (A), and higher than the stretching temperature A step of melt spinning an unstretched composite fiber in which a low-melting-point component (B) made of a resin composition containing an amorphous resin (b) having a glass transition point is disposed in at least two sea-island structures, the unstretched According to the manufacturing method, the composite fiber is subjected to a step of hot drawing at a temperature not lower than the melting point of the crystalline resin (a) and not higher than the melting point and not higher than the Tg of the amorphous resin (b). Can be manufactured well.
また、前記表現において「高融点成分（Ａ）を隔離する・・・低融点成分（Ｂ）」と表現した分割構造繊維に該当する製造方法を用いる場合は、繊維を溶融紡糸する工程において、複合繊維の径方向の断面において、繊維中央部から繊維表面に向かって高融点成分（Ａ）及び低融点成分（Ｂ）が略放射状に接合可能な紡糸ヘッド部を備えた紡糸装置を用い、紡糸ヘッド部における高融点成分（Ａ）の溶融粘度と低融点成分（Ｂ）の溶融粘度とを調整して、紡糸する繊維の製造方法とすればよい。 In addition, when using the manufacturing method corresponding to the split structure fiber expressed as “isolating the high melting point component (A) in the above expression, the low melting point component (B)”, in the step of melt spinning the fiber, Using a spinning device provided with a spinning head part capable of joining the high melting point component (A) and the low melting point component (B) almost radially from the center of the fiber toward the fiber surface in the cross section in the radial direction of the fiber, The melt viscosity of the high melting component (A) and the melt viscosity of the low melting component (B) in the part may be adjusted to produce a fiber to be spun.
（溶融紡糸工程）
本発明の製造方法における、繊維を溶融紡糸する工程は、従来の海島繊維の製造又は分割繊維の製造において使用されている公知の方法を用いることができる。例えば、前記の低融点成分および高融点成分を用い、押出し機２台と海島繊維用ノズル又は分割繊維ノズルを備えた複合紡糸装置により、紡糸温度２００〜３００℃程度で溶融紡糸することにより、海島構造又は分割構造の複合繊維を得ることができる。
(Melt spinning process)
In the production method of the present invention, the process of melt spinning the fiber may be a known method used in the production of conventional sea-island fibers or split fibers. For example, by using the above-mentioned low melting point component and high melting point component and melt spinning at a spinning temperature of about 200 to 300 ° C. with a compound spinning apparatus equipped with two extruders and a sea island fiber nozzle or a split fiber nozzle, A composite fiber having a structure or a divided structure can be obtained.
（熱延伸工程）
本発明の製造方法においては、前記溶融紡糸工程で得られた未延伸複合繊維を熱延伸処理する。この熱延伸処理は、結晶性樹脂（ａ）のガラス転移温度以上、融点以下の温度であって、かつ非晶性樹脂（ｂ）のＴｇ以下の温度で行われる。
該熱延伸工程においては、従来公知の熱延伸処理方法、例えば一般的に知られている金属加熱ロールや金属加熱板などを用いた接触加熱延伸、あるいは温水、常圧〜０．２ＭＰａ（ゲージ圧）程度の水蒸気や熱風などの加熱流体、高圧蒸気延伸、遠赤外線などの熱線を用いた非接触加熱延伸、及びこれらの組み合わせた方法などを適用することができる。
紙おむつ等、風合いを求められる用途において、延伸倍率は、繊維強度を発現させる観点から通常２〜６倍程度、好ましくは３〜５倍である。得られた延伸繊維における単糸繊度は、通常１〜１０ｄｔｅｘ程度、好ましくは２〜７ｄｔｅｘである。該延伸繊維は延伸により、特殊形状発現の起因となる低融点成分（Ｂ）の非晶性樹脂（ｂ）の海成分の剥離が起こる。
(Heat drawing process)
In the production method of the present invention, the unstretched composite fiber obtained in the melt spinning step is subjected to a heat stretching process. This heat stretching treatment is performed at a temperature not lower than the glass transition temperature of the crystalline resin (a) and not higher than the melting point, and not higher than Tg of the amorphous resin (b).
In the heat drawing step, a conventionally known heat drawing method, for example, contact heating drawing using a generally known metal heating roll or metal heating plate, or hot water, normal pressure to 0.2 MPa (gauge pressure). ) Heating fluid such as water vapor and hot air, high-pressure steam stretching, non-contact heating stretching using heat rays such as far-infrared rays, and a combination of these can be applied.
In applications where texture is required, such as paper diapers, the draw ratio is usually about 2 to 6 times, preferably 3 to 5 times, from the viewpoint of developing fiber strength. The single yarn fineness in the obtained drawn fiber is usually about 1 to 10 dtex, preferably 2 to 7 dtex. When the drawn fiber is drawn, the sea component of the amorphous resin (b) of the low melting point component (B) that causes the development of a special shape is peeled off.
（捲縮加工）
本発明においては、このようにして得られた繊維に通常は捲縮加工が施される。該捲縮加工方法としては特に制限はなく、従来ポリオレフィン系複合延伸繊維の捲縮加工に慣用されている方法を用いることができる。例えば、該延伸繊維に、常法により捲縮数１０〜１８個／２．５ｃｍ程度、好ましくは１２〜１６個／２．５ｃｍで機械捲縮を施すことにより、捲縮延伸繊維が得られる。
またこの工程で繊維に油剤を塗付（付着）させることによって、繊維及び熱風融着後の不織布特性として、カーディング等に対する高次加工性、不織布としての初期透水性、耐久親水性、撥水性、風合い等様々な性能を付与することができる。
(Crimping)
In the present invention, the fibers thus obtained are usually crimped. There is no restriction | limiting in particular as this crimping processing method, The method conventionally used for the crimping processing of the polyolefin composite stretched fiber can be used. For example, a crimped stretched fiber can be obtained by subjecting the stretched fiber to mechanical crimping by a conventional method at a crimp number of about 10 to 18 pieces / 2.5 cm, preferably 12 to 16 pieces / 2.5 cm.
In addition, by applying (attaching) an oil to the fiber in this step, the non-woven fabric characteristics after fiber and hot air fusion are high-order workability for carding and the like, initial water permeability as a non-woven fabric, durable hydrophilicity, water repellency Various performances such as texture can be imparted.
（切断工程）
必要に応じて乾燥処理を経て、１５〜１００ｍｍの短繊維に切断される。繊維長は、好ましくは２５〜６０ｍｍである。
(Cutting process)
If necessary, it is cut into short fibers of 15 to 100 mm through a drying treatment. The fiber length is preferably 25 to 60 mm.
次に本発明の不織布について説明する。
［不織布］
本発明の不織布は、結晶性樹脂（ａ）の融点以上、非晶性樹脂（ｂ）のガラス転移点以下の温度で加熱することにより、基材繊維としての複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部との二成分の分離構造を有している。
基材繊維を単位とする繊維軸方向における前記分離構造において、図２（Ｂ）に示す隣り合う塊状部２，２間の平均長さ（ｄ）が、１〜３００μｍ程度、好ましくは１０〜２００μｍであることが、保水性、耐久親水性、拡散性などの不織布の性能を向上できる観点から好ましい。
また、基材繊維を単位とする繊維軸方向における前記分離構造において、図２（Ｂ）に示す前記塊状部２を貫く繊維状部３の複数本の繊維間の長さ（ｇ）の平均長さが１〜５０μｍ程度、好ましくは３〜１０μｍであることが、保水性、耐久親水性、拡散性などの不織布の性能を向上できる観点から好ましい。
Next, the nonwoven fabric of this invention is demonstrated.
[Nonwoven fabric]
The nonwoven fabric of the present invention is heated at a temperature not lower than the melting point of the crystalline resin (a) and not higher than the glass transition point of the amorphous resin (b), so that the composite fiber as the base fiber has a low melting point component (B ) And a fibrous part mainly composed of the high melting point component (A) and penetrating between the massive parts.
In the separation structure in the fiber axis direction with the base fiber as a unit, the average length (d) between the adjacent massive portions 2 and 2 shown in FIG. 2B is about 1 to 300 μm, preferably 10 to 200 μm. It is preferable from the viewpoint of improving the performance of the nonwoven fabric such as water retention, durable hydrophilicity, and diffusibility.
Moreover, in the said separation structure in the fiber-axis direction which makes a base fiber a unit, the average length of the length (g) between several fibers of the fibrous part 3 which penetrates the said block-shaped part 2 shown to FIG. 2 (B) The thickness is preferably about 1 to 50 μm, preferably 3 to 10 μm from the viewpoint of improving the performance of the nonwoven fabric such as water retention, durable hydrophilicity, and diffusibility.
本発明の不織布の作製方法としては、熱融着法、熱ロール法、スパンレース法、ニードルパンチ法などがあるが、本発明においては、熱融着法、特に熱風融着法を採用するのが有利である。この熱融着法、特に熱風融着法で不織布を作製した場合、不織布の作製と同時に、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、塊状部間を貫く繊維状部との二成分の分離構造が発現し、所望の不織布が容易に得られるからである。
この熱風融着法による不織布の製造方法としては特に制限はなく、従来、熱風融着加工による不織布の製造において慣用されている方法を用いることができる。例えば前述したようにして得られた短繊維を、ローラーカード機にてカーディングして所望の目付重量のウェッブを作製したのち、エアースルー方式等の熱風融着法により、当該不織布が得られる。
この際、熱風融着は、結晶性樹脂（ａ）の融点以上の温度で行うことが肝要であり、特に結晶性樹脂（ａ）の融点以上、かつ非晶性樹脂（ｂ）のガラス転移点以下の温度で行うことがより好ましい。
As a method for producing the nonwoven fabric of the present invention, there are a thermal fusion method, a thermal roll method, a spunlace method, a needle punch method, etc., but in the present invention, a thermal fusion method, particularly a hot air fusion method is adopted. Is advantageous. When a nonwoven fabric is produced by this heat fusion method, particularly the hot-air fusion method, at the same time as the production of the nonwoven fabric, a lump portion formed by agglomeration of the low melting point component (B) and a high melting point component (A) are mainly formed. This is because a two-component separation structure with a fibrous portion penetrating between the portions appears and a desired nonwoven fabric can be easily obtained.
There is no restriction | limiting in particular as a manufacturing method of the nonwoven fabric by this hot-air melt | fusion method, The method conventionally conventionally used in manufacture of the nonwoven fabric by a hot-air melt | fusion process can be used. For example, after the short fiber obtained as described above is carded with a roller card machine to produce a web having a desired weight per unit area, the nonwoven fabric can be obtained by a hot air fusion method such as an air-through method.
At this time, it is important that the hot-air fusion is performed at a temperature equal to or higher than the melting point of the crystalline resin (a). In particular, the glass transition point of the amorphous resin (b) is equal to or higher than the melting point of the crystalline resin (a). It is more preferable to carry out at the following temperature.
前述のようにして得られた不織布は、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、塊状部間を貫く繊維状部との二成分の分離構造を持つため、例えば１０〜２００μｍで形成された塊状部間を貫く、繊維間の長さが３〜１０μｍの繊維状部間の微細な空間に液体が保持されるので高い保水性を発揮できる。またこの形状により、強い毛細管現象が働くため、高い拡散性、吸い上げ高さを発揮できる。 The nonwoven fabric obtained as described above is a two-component separation of a massive part formed by aggregation of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) and penetrating between the massive parts. Since it has a structure, for example, a liquid is held in a fine space between the fibrous portions having a length of 3 to 10 μm that penetrates between the massive portions formed at 10 to 200 μm, so that high water retention can be exhibited. . In addition, this shape causes a strong capillary phenomenon, so that high diffusibility and suction height can be exhibited.
［不織布の特殊形状（二成分分離構造）発現メカニズムの考察］
３〜５倍で熱延伸時、結晶性樹脂（ａ）は伸びやすく非晶性樹脂（ｂ）は伸びにくいため、結晶性樹脂（ａ）は伸ばされるが非晶性樹脂（ｂ）は低倍率で切断され、特殊形状の核が形成され、二成分分離構造の発現能を潜在的に保有した基材繊維となる。不織布作成時、結晶性樹脂（ａ）の融点以上、非晶性樹脂（ｂ）のガラス転移点以下の熱風融着処理を行うことで、延伸時に切断された非晶性樹脂（ｂ）が収縮し塊状部を形成する。溶けた結晶性樹脂（ａ）がそれに追従して動くため、高融点成分（Ａ）を主体とする成分が塊状部間を貫く繊維状部として露出した形状が形成されると考えられる。
[Consideration of mechanism for developing special shape (two-component separation structure) of nonwoven fabric]
When heat-stretched at 3 to 5 times, the crystalline resin (a) is easy to stretch and the amorphous resin (b) is difficult to stretch, so the crystalline resin (a) is stretched but the amorphous resin (b) is low To form a specially shaped nucleus, resulting in a base fiber that potentially possesses the ability to develop a two-component separation structure. At the time of making the nonwoven fabric, the amorphous resin (b) cut at the time of stretching contracts by performing hot air fusion treatment not lower than the melting point of the crystalline resin (a) and not higher than the glass transition point of the amorphous resin (b). A lumpy portion is formed. Since the melted crystalline resin (a) moves following it, it is thought that a shape in which the component mainly composed of the high melting point component (A) is exposed as a fibrous portion penetrating between the massive portions is formed.
また、本発明は、上述の本発明の不織布を表面布に用いてなる衛生材料をも提供する。 Moreover, this invention also provides the sanitary material which uses the above-mentioned nonwoven fabric of this invention for a surface cloth.
以下に本発明について実施例及び比較例によって詳細に説明するが、本発明はこれらの例によってなんら限定されるものではない。なお、以下の実施例、比較例において、共通する条件についてまとめて示す。 Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, common conditions are collectively shown.
（１）紡糸工程における冷却条件
以下の実施例及び比較例において、繊維の溶融紡糸工程における紡出繊維の冷却は、横風冷却装置を用い、冷却風速３．８ｍ／ｓｅｃ、風温２２℃として行った。
（２）延伸ローラー温度条件
分割性複合未延伸繊維を所定のトータル繊度に集束し、それぞれの表面温度に制御可能な第１〜第４の延伸ローラーを用い、第１ローラー温度８０℃、第２ローラー温度１００℃、第３ローラー温度８５℃、第４ローラー温度７５℃とし、延伸温度としてのローラー間の温度を９８℃として、第１〜第４の延伸ローラー間でトータル４倍の延伸を行った。
(1) Cooling conditions in the spinning process In the following examples and comparative examples, the spinning fiber in the fiber melt spinning process is cooled using a cross wind cooling device at a cooling air speed of 3.8 m / sec and an air temperature of 22 ° C. It was.
(2) Stretching roller temperature conditions The first to fourth stretching rollers that are capable of controlling the respective surface temperatures by focusing the splittable composite unstretched fibers to a predetermined total fineness, the first roller temperature of 80 ° C., the second The roller temperature is 100 ° C., the third roller temperature is 85 ° C., the fourth roller temperature is 75 ° C., the temperature between the rollers as the stretching temperature is 98 ° C., and the stretching is performed four times in total between the first to fourth stretching rollers. It was.
実施例、比較例における用語の定義と物性の評価方法は以下の通りである。 Definitions of terms and evaluation methods of physical properties in Examples and Comparative Examples are as follows.
（隣り合う塊状部間の平均長さ）
熱風融着後の不織布表面を電子顕微鏡で撮影した。得られた写真から、低融点成分（Ｂ）による塊状部間の、高融点成分（Ａ）（島繊維）の繊維束を任意に１００本選び、その長さ、図２（Ｂ）における（ｄ）（μｍ）を測定し、平均長さを求めた。なお隣り合う塊状部間の長さとは、塊状部間にできた空間の最大長さを意味する。また高融点成分（Ａ）（島繊維）が湾曲、もしくは折れ曲がっている場合は、その湾曲もしくは折れ曲がりに沿って空間長さを測定した、その最大の長さである。
(Average length between adjacent blocks)
The surface of the nonwoven fabric after hot air fusion was photographed with an electron microscope. From the obtained photograph, 100 fiber bundles of the high melting point component (A) (island fiber) between the block parts of the low melting point component (B) are arbitrarily selected, and the length, (d in FIG. 2B) ) (Μm) was measured to determine the average length. In addition, the length between adjacent block parts means the maximum length of the space formed between the block parts. Further, when the high melting point component (A) (island fiber) is curved or bent, the maximum length is obtained by measuring the space length along the curved or bent.
（高融点成分（Ａ）（島繊維）を主体としてなる繊維の平均太さ）
熱風融着後の不織布表面を電子顕微鏡で撮影した。得られた写真から、高融点成分（Ａ）（島繊維）を主体としてなる繊維を任意に１００本選び、繊維の太さ、図２（Ｂ）における（ｈ）（μｍ）を測定し、平均太さを求めた。なお高融点成分（Ａ）（島繊維）を主体としてなる繊維の太さとは、島繊維を芯とする繊維の太さの最大部の長さを意味する。また、島繊維を芯とする繊維とは、後述する二成分分離構造において完全に高融点成分（Ａ）の成分のみからなる形成される島繊維を意味するものではなく、高融点成分（Ａ）の成分を芯として、その外周に低融点成分（Ｂ）の被膜が存在している形態の繊維、すなわち、高融点成分（Ａ）（島繊維）を主体としてなる繊維を意味している。
(Average thickness of fiber mainly composed of high melting point component (A) (island fiber))
The surface of the nonwoven fabric after hot air fusion was photographed with an electron microscope. From the obtained photograph, 100 fibers mainly composed of the high melting point component (A) (island fibers) were arbitrarily selected, and the fiber thickness, (h) (μm) in FIG. I asked for thickness. In addition, the thickness of the fiber mainly composed of the high melting point component (A) (island fiber) means the maximum length of the fiber having the island fiber as a core. Further, the fiber having the island fiber as the core does not mean an island fiber formed entirely of the component of the high melting point component (A) in the two-component separation structure described later, but the high melting point component (A). The fiber of the form in which the coating of the low melting point component (B) exists on the outer periphery thereof, that is, the fiber mainly composed of the high melting point component (A) (island fiber).
（高融点成分（Ａ）（島繊維）を主体とする繊維状部の繊維間の平均長さ）
熱風融着後の不織布表面を電子顕微鏡で撮影し、得られた写真から、高融点成分（Ａ）（島繊維）を主体とする繊維間の長さを任意に１００箇所選び、その長さ、図２（Ｂ）における（ｇ）（μｍ）を測定し、平均長さを求めた。なお高融点成分（Ａ）（島繊維）を主体とする繊維間の長さとは、島繊維を芯とする繊維間にできた空間の最大幅を意味する。
(Average length between fibers of the fibrous portion mainly composed of the high melting point component (A) (island fiber))
The surface of the nonwoven fabric after hot air fusion was photographed with an electron microscope, and from the obtained photograph, 100 lengths between fibers mainly composed of the high melting point component (A) (island fibers) were selected, the length, (G) (micrometer) in FIG.2 (B) was measured and the average length was calculated | required. The length between fibers mainly composed of the high melting point component (A) (island fibers) means the maximum width of the space formed between the fibers having the island fibers as the core.
（二成分分離構造の形状パターン）
低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部との二成分の分離構造を有する（以下、「二成分分離構造」という。）形状パターンは以下のように評価した。
○：二成分分離構造が形成されており、その形状が顕著な場合
△：二成分分離構造が一部の繊維のみで形成されている場合
×：二成分分離構造が形成されていない場合
(Shape pattern of two-component separation structure)
It has a two-component separation structure composed of a massive part formed by agglomeration of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) (hereinafter referred to as “two-component separation”). The structure pattern was evaluated as follows.
◯: When a two-component separation structure is formed and the shape is remarkable Δ: When the two-component separation structure is formed of only some fibers ×: When a two-component separation structure is not formed
（吸い上げ高さ）
目付け２０ｇ／ｍ2で作製した不織布を、ＪＩＳ Ｌ １９０７ のバイレック法に準拠して、長さ２００ｍｍ×幅２５ｍｍの不織布の長さ方向の先端２０ｍｍを生理食塩水に浸け、１０分後の吸い上げ高さ（ｍｍ）を測定した。
(Suction height)
A nonwoven fabric produced with a basis weight of 20 g / m 2 is soaked in a normal saline 20 mm length tip of a nonwoven fabric having a length of 200 mm and a width of 25 mm in accordance with JIS L 1907 Bayrec method. The thickness (mm) was measured.
（保水率）
目付け２０ｇ／ｍ2で作製した不織布を、ＪＩＳ Ｌ １９０７ の吸水率測定に準拠して、７５ｍｍ×７５ｍｍの不織布を８０℃で３０分乾燥後、２０℃、６５％ＲＨの恒温室で２４時間調湿し、調湿後の重量をＷ1とする。次に２０℃の生理食塩水に２０分浸漬させ、その後２枚の乾燥した濾紙で挟み、ニップロールを用いて圧力０．１ＭＰａ、絞り速度２５ｍｍ／ｓｅｃで加圧し水分を搾り取り、その重量Ｗ2を測定した。保水率を下記の計算式より算出した。
保水率＝（Ｗ2−Ｗ1）／Ｗ1×１００％
(Water retention rate)
Based on the water absorption measurement of JIS L 1907, the nonwoven fabric produced with a basis weight of 20 g / m 2 was dried at 80 ° C. for 30 minutes and then adjusted in a constant temperature room at 20 ° C. and 65% RH for 24 hours. The weight after dampening and conditioning is W 1 . Next, it is immersed in physiological saline at 20 ° C. for 20 minutes, and then sandwiched between two dried filter papers. Using a nip roll, it is pressurized at a pressure of 0.1 MPa and a squeezing speed of 25 mm / sec to squeeze out moisture, and its weight W 2 Was measured. The water retention rate was calculated from the following formula.
Water retention rate = (W 2 −W 1 ) / W 1 × 100%
（耐久親水性）
目付け２０ｇ／ｍ2で作製した不織布を濾紙の上に設置し、不織布面から任意に１０箇所を選抜し生理食塩水を滴下する。滴下後２秒以内に濾紙への吸水が確認されれば透水したと判断する。滴下から３分間静置し、その後濾紙を変え同一箇所へ繰り返し滴下することを１０回行い、１０箇所中１０箇所吸収され続ける滴下回数を測定した。
(Durable hydrophilic)
A non-woven fabric produced with a basis weight of 20 g / m 2 is placed on a filter paper, 10 locations are selected arbitrarily from the non-woven fabric surface, and physiological saline is dropped. If water absorption to the filter paper is confirmed within 2 seconds after dropping, it is determined that water has permeated. The solution was allowed to stand for 3 minutes from the dropping, and then the filter paper was changed and repeatedly dropped into the same place 10 times.
（液拡散性）
目付け２０ｇ／ｍ2で３００ｍｍ×３００ｍｍの不織布を疎水性のプラスチック板の上に固定し、内径３０ｍｍの円筒を乗せ、その中に生理食塩水３０ｍｌを１ｍｌ／ｓｅｃで滴下する。滴下後に円筒をはずし、滴下終了から２分後に液体が拡散している部分の長手方向と幅方向の長さを測定する。長手方向の拡散距離ｌ1（ｍｍ）、幅方向の拡散距離をｌ2（ｍｍ）としたとき、拡散比率と拡散面積S（ｍｍ2）を下記の計算式より算出する。
拡散比率＝ｌ1／ｌ2
拡散面積Ｓ＝（ｌ1／２）×（ｌ2／２）×π
紙おむつやナプキン等の衛生材料では、長さの短い幅方向から液体の漏れが起こりやすい（一般的に横モレと言われる）。拡散比率が高ければ長手方向に優先的に液体が流れやすくなり、横モレが起こりにくくなるため好ましい。
また、拡散面積が大きいほど液体の拡散性が良くなり、下部の吸収体の利用効率が上がるため好ましい。さらに、同量の液体を吸収するとき、拡散面積が大きいほど単位面積当たりの液体吸収量が減るため、吸収体の厚み変化が小さくなり着用時の圧迫感が少なくなるため好ましい。拡散面積の増大は、本発明の繊維構造による毛細管現象が効果的に影響するものと考えられる。
(Liquid diffusibility)
A non-woven fabric of 300 mm × 300 mm with a basis weight of 20 g / m 2 is fixed on a hydrophobic plastic plate, a cylinder with an inner diameter of 30 mm is placed, and 30 ml of physiological saline is dropped into it at 1 ml / sec. After dropping, the cylinder is removed, and the length in the longitudinal direction and the width direction of the portion where the liquid is diffused is measured 2 minutes after the end of dropping. When the diffusion distance l 1 (mm) in the longitudinal direction and the diffusion distance in the width direction are l 2 (mm), the diffusion ratio and the diffusion area S (mm 2 ) are calculated from the following calculation formula.
Diffusion ratio = l 1 / l 2
Spread area S = (l 1/2) × (l 2/2) × π
In sanitary materials such as disposable diapers and napkins, liquid leakage is likely to occur from the short width direction (generally referred to as transverse mole). A high diffusion ratio is preferable because liquid tends to flow preferentially in the longitudinal direction, and horizontal leakage hardly occurs.
Moreover, the larger the diffusion area, the better the diffusibility of the liquid and the higher the utilization efficiency of the lower absorber, which is preferable. Further, when the same amount of liquid is absorbed, the larger the diffusion area, the smaller the amount of liquid absorption per unit area, so the change in the thickness of the absorbent body becomes smaller and the feeling of pressure when worn is reduced, which is preferable. It is considered that the increase in the diffusion area is effectively influenced by the capillary phenomenon due to the fiber structure of the present invention.
実施例１
（１）未延伸繊維の作製
高融点成分（Ａ）材料として、ホモポリプロピレン［プライムポリマー社製、商品名「Ｓ１３５」、ＭＦＲ（２３０℃、２．１６ｋｇ）＝９ｇ／１０分、融点：１６１℃］。
低融点成分（Ｂ）材料の結晶性樹脂（ａ）として、高密度ポリエチレン［旭化成社製、商品名「Ｊ３０２」、ＭＦＲ（１９０℃、２．１６ｋｇ）＝３８ｇ／１０分、融点：１３０℃、Ｔｇ：−１２０℃］、非晶性樹脂（ｂ）として環状オレフィンコポリマー［ポリプラスチック社製、登録商標「ＴＯＰＡＳ ５０１３」、Ｔｇ＝１３４℃、２６０℃／２．１６ｋｇでのメルトボリュームレイト（ＭＶＲ）＝４８ｍｌ／１０分］を質量比９０：１０の割合で含む樹脂組成物を用いた。
一軸押出機２台と未延伸単繊維において４つの島を形成できる６００ホールの海島繊維用ノズルを備えた複合紡糸装置により、高融点成分（Ａ）：低融点成分（Ｂ）＝質量比４０：６０の割合で、紡糸温度２８０℃、前記冷却条件、及び引取速度１５０ｍ／分で紡糸し、単糸繊度が１２．２ｄｔｅｘの未延伸繊維を作製した。
（２）延伸繊維の作製
上記（１）で得られた未延伸繊維を集束し、前記の延伸ローラー温度条件のローラー間で、延伸温度９８℃の条件で延伸処理して、延伸倍率４倍で単糸繊度が３．３ｄｔｅｘである延伸繊維を作製した。
（３）短繊維の作製
上記（２）で得られた延伸繊維に１５個／２５ｍｍの機械捲縮加工を施した。その後ロータリーカッターで５０ｍｍの長さにカットすることにより、短繊維を作製した。
（４）油剤の付着
上記（３）で得られた短繊維に耐久親水油剤（主組成：特殊グリセリンエステル）を付着率０．５質量％で付着させ、１００℃の乾燥機にて１０分間熱処理し油剤付き短繊維を作製した。
Example 1
(1) Production of unstretched fiber As a high melting point component (A) material, homopolypropylene [manufactured by Prime Polymer, trade name “S135”, MFR (230 ° C., 2.16 kg) = 9 g / 10 min, melting point: 161 ° C. ].
As the crystalline resin (a) of the low melting point component (B) material, high density polyethylene [manufactured by Asahi Kasei Co., Ltd., trade name “J302”, MFR (190 ° C., 2.16 kg) = 38 g / 10 min, melting point: 130 ° C., Tg: -120 ° C., cyclic olefin copolymer as amorphous resin (b) [manufactured by Polyplastics, registered trademark “TOPAS 5013”, Tg = 134 ° C., melt volume rate (MVR) at 260 ° C./2.16 kg = 48 ml / 10 min] was used at a mass ratio of 90:10.
A high-melting-point component (A): a low-melting-point component (B) = a mass ratio of 40 by a composite spinning apparatus equipped with two uniaxial extruders and a 600-hole sea-island fiber nozzle capable of forming four islands in unstretched monofilaments. Spinning was performed at a rate of 60 at a spinning temperature of 280 ° C., the above cooling conditions, and a take-up speed of 150 m / min to produce an undrawn fiber having a single yarn fineness of 12.2 dtex.
(2) Production of stretched fibers The unstretched fibers obtained in (1) above are converged and stretched at a stretching temperature of 98 ° C. between rollers under the above-mentioned stretching roller temperature conditions, and the stretching ratio is 4 times. A drawn fiber having a single yarn fineness of 3.3 dtex was produced.
(3) Production of short fiber The crimped fiber of 15 pieces / 25 mm was applied to the drawn fiber obtained in the above (2). Thereafter, the fiber was cut into a length of 50 mm with a rotary cutter to produce a short fiber.
(4) Adhesion of oil agent A durable hydrophilic oil agent (main composition: special glycerin ester) is attached to the short fibers obtained in (3) at an adhesion rate of 0.5% by mass and heat-treated for 10 minutes in a dryer at 100 ° C. A short fiber with coconut oil was prepared.
（５）不織布の作製
上記（４）で得られた油剤付き短繊維を用い、３６０ｍｍ幅のローラーカード機にて２０ｍ／分の速度でカーディングし、目付６．７ｇ／ｍ2のウェッブを吐出させて、これを３層に積層し、目付２０ｇ／ｍ2のウェッブを得た。次に、このウェッブを幅３５０ｍｍ、速度５ｍ／ｍｉｎの金網ベルトに載せ、風温１３５℃、風速２．７ｍ／ｓｅｃの熱風を５秒間吹きつける熱風融着法により熱融着不織布を作製した。繊維の組成、加工条件、不織布物性等をまとめて第１表に示す。また図３に熱融着不織布の走査型電子顕微鏡（ＳＥＭ）写真を示す。
得られた不織布には低融点成分（Ｂ）の塊状部、およびこの塊状部を貫く高融点成分（Ａ）を主体とする繊維状部が形成された二成分分離構造が一部の繊維で形成されていた。
(5) Fabrication of nonwoven fabric Using the short fiber with oil obtained in (4) above, carding is carried out at a speed of 20 m / min with a roller card machine having a width of 360 mm, and a web having a basis weight of 6.7 g / m 2 is discharged. This was laminated into three layers to obtain a web having a basis weight of 20 g / m 2 . Next, this web was placed on a wire mesh belt having a width of 350 mm and a speed of 5 m / min, and a heat-bonded nonwoven fabric was produced by a hot-air fusion method in which hot air having a wind temperature of 135 ° C. and a wind speed of 2.7 m / sec was blown for 5 seconds. The fiber composition, processing conditions, non-woven fabric properties, etc. are summarized in Table 1. FIG. 3 shows a scanning electron microscope (SEM) photograph of the heat-sealed nonwoven fabric.
The resulting non-woven fabric is formed of a part of a two-component separation structure in which a mass part of a low melting point component (B) and a fibrous part mainly composed of a high melting point component (A) penetrating the mass part are formed. It had been.
実施例２
実施例１（１）において、低融点成分（Ｂ）を構成する結晶性樹脂（ａ）：非晶性樹脂（ｂ）＝質量比８５：１５の割合に変えた以外は実施例１と同様にして不織布を作製した。繊維の組成、加工条件、不織布物性等をまとめて第１表に示す。また図４に熱風融着不織布の走査型電子顕微鏡（ＳＥＭ）写真を示す。
得られた不織布には、低融点成分（Ｂ）の塊状部、およびこの塊状部を貫く高融点成分（Ａ）を主体とする繊維状部による二成分分離構造が形成されており、その形状が顕著であった。
Example 2
Example 1 (1) is the same as Example 1 except that the ratio of crystalline resin (a): noncrystalline resin (b) constituting the low melting point component (B) = mass ratio 85:15 is changed. A nonwoven fabric was prepared. The fiber composition, processing conditions, non-woven fabric properties, etc. are summarized in Table 1. FIG. 4 shows a scanning electron microscope (SEM) photograph of the hot-air fused nonwoven fabric.
The resulting non-woven fabric has a two-component separation structure formed by a fibrous portion mainly composed of a low melting point component (B) and a high melting point component (A) penetrating the massive portion. It was remarkable.
比較例１
実施例１において、高融点成分（Ａ）：低融点成分（Ｂ）＝質量比５０：５０、低融点成分（Ｂ）を構成する結晶性樹脂（ａ）：非晶性樹脂（ｂ）＝質量比９２：８の割合に変えた以外は実施例１と同様に作製した。繊維の組成、加工条件、不織布物性等をまとめて第１表に示す。また図５に熱風融着不織布の走査型電子顕微鏡（ＳＥＭ）写真を示す。
得られた不織布には、低融点成分（Ｂ）の塊状部、およびこの塊状部を貫く高融点成分（Ａ）を主体とする繊維状部による二成分分離構造が形成されなかった。
Comparative Example 1
In Example 1, high melting point component (A): low melting point component (B) = mass ratio 50:50, crystalline resin (a) constituting low melting point component (B): amorphous resin (b) = mass It was produced in the same manner as in Example 1 except that the ratio was changed to a ratio of 92: 8. The fiber composition, processing conditions, non-woven fabric properties, etc. are summarized in Table 1. FIG. 5 shows a scanning electron microscope (SEM) photograph of the hot-air fused nonwoven fabric.
In the obtained non-woven fabric, a two-component separation structure was not formed by a lump part of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) penetrating the lump part.
比較例２
実施例１において、複合紡糸ノズルを海島構造ノズルから同芯複合繊維に変えた以外は実施例１と同様に作製した。繊維の組成、加工条件、不織布物性等をまとめて第１表に示す。また図６に熱風融着不織布の走査型電子顕微鏡（ＳＥＭ）写真を示す。
得られた不織布には、低融点成分（Ｂ）の塊状部、およびこの塊状部を貫く高融点成分（Ａ）を主体とする繊維状部による二成分分離構造が形成されなかった。
Comparative Example 2
In Example 1, it produced similarly to Example 1 except having changed the composite spinning nozzle from the sea-island structure nozzle to the concentric composite fiber. The fiber composition, processing conditions, non-woven fabric properties, etc. are summarized in Table 1. FIG. 6 shows a scanning electron microscope (SEM) photograph of the hot-air fused nonwoven fabric.
In the obtained non-woven fabric, a two-component separation structure was not formed by a lump part of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) penetrating the lump part.
本発明によれば、保水性、拡散性、吸い上げ高さ、耐久親水性に優れた不織布を提供することができる。本発明の不織布は、該不織布を構成する低融点成分（Ｂ）の塊状部、およびこの塊状部を貫く高融点成分（Ａ）を主体とする繊維状部による二成分分離構造が形成されるので、１０〜２００μｍで形成された塊状部間を貫く、繊維間の長さ(間隙)が３〜１０μｍの繊維状部間の微細な空間に液体が保持されるので高い保水性を発揮できる。またこの形状により強く毛細管現象が働くため、高い拡散性、吸い上げ高さを発揮する。これにより、紙おむつやナプキンの表面材や、最近の紙おむつの３構造（吸収体／セカンドシート／トップシート）においてセカンドシート用途として用いれば高い保水性、拡散性、耐久親水性を発揮できる。また、本発明の不織布は吸い上げ高さが向上する。 ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric excellent in water retention, a diffusivity, the siphoning height, and durable hydrophilic property can be provided. In the nonwoven fabric of the present invention, a two-component separation structure is formed by a mass portion of the low melting point component (B) constituting the nonwoven fabric and a fibrous portion mainly composed of the high melting point component (A) penetrating the mass portion. Since the liquid is held in a fine space between the fibrous portions having a length (gap) between the fibers of 3 to 10 μm that penetrates between the massive portions formed at 10 to 200 μm, high water retention can be exhibited. In addition, the capillary action works strongly with this shape, so it exhibits high diffusivity and suction height. Thereby, if it is used as a second sheet application in the surface material of a paper diaper or napkin and the three structures of a recent paper diaper (absorber / second sheet / top sheet), high water retention, diffusibility and durable hydrophilicity can be exhibited. Moreover, the non-woven fabric of the present invention improves the sucking height.
１． 熱接着性複合繊維
２． 塊状部
３． 繊維部
３' 繊維
Ａ 高融点成分（Ａ）
Ｂ 低融点成分（Ｂ）
ｄ 塊状部間の長さ（間隔）
ｇ 繊維状部（島繊維を芯とする）における繊維間の長さ（間隙）
ｈ 繊維状部（島繊維を芯とする）の太さ
1. 1. Thermal adhesive composite fiber 2. Bulk part Fiber part 3 'Fiber A High melting point component (A)
B Low melting point component (B)
d Length (interval) between massive parts
g Length (gap) between fibers in the fibrous part (core island fiber)
h Thickness of fibrous part (core island fiber)
Claims (8)
（１）該熱接着性複合繊維における高融点成分（Ａ）と低融点成分（Ｂ）の質量比が高融点成分（Ａ）／低融点成分（Ｂ）＝４５／５５〜３５／６５であり、
（２）該低融点成分（Ｂ）の結晶性樹脂（ａ）の融点が、非晶性樹脂（ｂ）のガラス転移点以下の温度であり、
（３）該非晶性樹脂（ｂ）の含有率が熱接着性複合繊維全体に対して、５質量％以上であり、かつ
（４）該複合繊維を熱融着した不織布において、基材繊維の複合繊維が、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体として該塊状部を貫く繊維状部との二成分の分離構造を呈している。 A high-melting-point component (A) made of a thermoplastic resin and separated from each other, and a crystalline resin (a) and an amorphous resin (b) that isolate or surround the high-melting-point component (A) A non-woven fabric formed by heat-sealing a base fiber composed of a heat-adhesive conjugate fiber composed of a low-melting-point component (B) composed of a resin composition comprising the following (1) to (4) A nonwoven fabric characterized by satisfying the following conditions.
(1) The mass ratio of the high melting point component (A) and the low melting point component (B) in the thermoadhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65. ,
(2) The melting point of the crystalline resin (a) of the low melting point component (B) is a temperature below the glass transition point of the amorphous resin (b),
(3) The content of the amorphous resin (b) is 5% by mass or more with respect to the entire heat-adhesive conjugate fiber, and (4) In the nonwoven fabric obtained by heat-sealing the conjugate fiber, The composite fiber has a two-component separation structure of a massive part formed by aggregation of the low melting point component (B) and a fibrous part mainly composed of the high melting point component (A) and penetrating through the massive part.
該熱融着工程を、低融点成分（Ｂ）の結晶性樹脂（ａ）の融点以上であり、かつ非晶性樹脂（ｂ）のガラス転移点以下の温度で行うことによって、基材繊維としての複合繊維に、低融点成分（Ｂ）が凝集してなる塊状部と、高融点成分（Ａ）を主体とし、該塊状部間を貫く繊維状部とに分離した構造を発現させることを特徴とする不織布の製造方法。 The mass ratio of the high melting point component (A) and the low melting point component (B) in the heat-adhesive conjugate fiber is high melting point component (A) / low melting point component (B) = 45/55 to 35/65, The melting point of the crystalline resin (a) of the component (B) is a temperature not higher than the glass transition point of the amorphous resin (b), and the content of the amorphous resin (b) is the entire thermoadhesive conjugate fiber. With respect to the raw material composition of 5% by mass or more, at least two high melting point components (A) made of a thermoplastic resin and separated from each other, and the high melting point component (A) are isolated or surrounded. A step of melt-spinning as a heat-adhesive conjugate fiber composed of a low-melting-point component (B) made of a resin composition containing a crystalline resin (a) and an amorphous resin (b) at a predetermined magnification Substrate fibers obtained through a drawing process, further crimping, oil agent adhesion, and cutting into short fibers The process of making the heat-adhesive conjugate fiber as an assembly of webs by a conventional method, and the heat-bonding process at a temperature equal to or higher than the melting point of the crystalline resin (a) of the low-melting-point component (B) A method for producing a nonwoven fabric, comprising:
By performing the thermal fusion process at a temperature not lower than the melting point of the crystalline resin (a) of the low melting point component (B) and not higher than the glass transition point of the amorphous resin (b), The composite fiber is made to exhibit a structure in which the low melting point component (B) is agglomerated and the high melting point component (A) as a main component and separated into a fibrous part penetrating between the bulk parts. A method for producing a nonwoven fabric.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US10494748B2 (en) | 2015-06-03 | 2019-12-03 | Polyplastics Co., Ltd. | Thermal bond non-woven fabric containing cyclic olefin resin |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2003519296A (en) * | 1999-12-30 | 2003-06-17 | ビービーエイ・ノンウォーヴンズ・シンプソンヴィル，インコーポレイテッド | Multicomponent fibers and fabrics made therefrom |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2003519296A (en) * | 1999-12-30 | 2003-06-17 | ビービーエイ・ノンウォーヴンズ・シンプソンヴィル，インコーポレイテッド | Multicomponent fibers and fabrics made therefrom |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10494748B2 (en) | 2015-06-03 | 2019-12-03 | Polyplastics Co., Ltd. | Thermal bond non-woven fabric containing cyclic olefin resin |
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