JP6434794B2 - Composite fiber made of acrylic block copolymer - Google Patents

Description

  The present invention relates to a fiber nonwoven fabric, and more specifically, is composed of fibers mainly composed of a (meth) acrylic block copolymer having a specific structure, and has excellent flexibility, stretchability, and light resistance. Related to fiber nonwoven fabric

  Conventionally, a fabric made of a thermoplastic elastomer resin is known as a stretchable fabric. For example, Patent Document 1 describes a polyurethane melt blown nonwoven fabric. Patent Document 2 discloses a melt blown nonwoven fabric made of a styrene elastomer. Although these thermoplastic elastomer nonwoven fabrics have excellent stretchability, they are insufficient in light resistance, so when used for industrial materials such as agricultural materials, civil engineering materials, filter materials, etc. that are often used outdoors. In order to improve the light resistance of the nonwoven fabric, it is necessary to use a method of adding additives such as a weather resistance stabilizer and a heat resistance stabilizer. However, the method of adding the additive only improves the light resistance in the initial stage, and is often insufficient from the viewpoint of long-term light resistance, and these additives are often mixed with the raw material. When used outdoors, there are problems that the additive on the fiber surface of the nonwoven fabric dissolves or drops off, contaminates the environment, and the flexibility is impaired.

  Patent Document 3 discloses that a polyurethane elastomer having a glass transition temperature in the range of 15 ° C. to 50 ° C. and a specific thermoplastic polymer, which are suitable for fabrics that give a good wearing feeling to the dynamic movement of the human body, Combined with this thermoplastic polymer to cover a specific proportion of the circumference of the polyurethane elastomer, it is well described for fiberization and fabrication even when using a polyurethane elastomer having a low glass transition temperature. ing. However, even when it is made into fibers, it has a defect derived from polyurethane in light resistance and dyeability, and there is a problem that it is difficult to maintain long-term quality.

JP 59-223347 A JP 62-84143 A International Publication No. 2013/115094 Pamphlet

  The object of the present invention is not only to be used for fabrics including knitted fabrics, woven fabrics and nonwoven fabrics, which have excellent light resistance over a long period of time and also have flexibility and stretchability, but also pass through the process when producing fabrics. It is to provide a yarn having good properties.

  As a result of various studies on yarns suitable for fabrics that give excellent light resistance, flexibility, and stretchability, the inventors of the present invention have found that a polymer block mainly composed of specific acrylate units and methacrylate units. It is important to have a low glass transition temperature in a specific range in a fiber made of an acrylic block copolymer composed of a polymer block as a main component. On the other hand, it has such a low glass transition temperature. In some cases, fiberization and fabricization were very difficult. As a result of diligent studies to solve the above problems, the present inventors combined this acrylic block copolymer with a specific thermoplastic polymer, and this thermoplastic polymer was used to surround the acrylic block copolymer. The present invention was completed by discovering that, when a specific ratio was covered and composited, even when an acrylic block copolymer having a low glass transition temperature was used, it could be made into fibers and fabrics satisfactorily.

That is, the present invention provides an acrylic block copolymer (component A) composed of a polymer block (a1) composed of an acrylate unit and a polymer block (a2) composed of a methacrylic ester unit, and is easily soluble. Or a composite fiber composed of an easily decomposable thermoplastic polymer (component B), wherein the composite ratio (mass ratio) of component A and component B is A: B = 90: 10 to 40:60, and the fiber In the cross section, the A component is a core, and the B component is a composite fiber that covers 70% or more of the entire circumference of the A component.

  In the composite fiber, the content of the polymer block (a1) in the component A is 65% by mass or more, and the ratio of the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the component A (Mw / Mn) Is preferably 1.0 to 1.6.

  The composite fiber is preferably a triblock copolymer in which the component A is a polymer block (a2) bonded to both ends of the polymer block (a1).

  In the composite fiber, the component B is preferably formed of at least one selected from a thermoplastic polyvinyl alcohol polymer and a readily soluble polyester.

The composite fiber preferably has a single fiber fineness of 0.3 to 50 dtex .

  The composite fiber preferably has a core-sheath structure in which the A component is a core component and the B component is a sheath component.

  The present invention also includes a preparation step for preparing the conjugate fiber, a conjugate fiber fabric production step for producing a fabric composed of conjugate fibers using the conjugate fiber, and removing the B component from the fabric. A method for producing an acrylic block copolymer fabric, comprising a removal step of obtaining an acrylic block copolymer fabric.

  It should be noted that any combination of at least two components disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims recited in the claims is included in the present invention.

  In the present invention, a specific acrylic block copolymer is combined with a specific thermoplastic polymer, and these are composite-spun with a specific structure, so that an acrylic block copolymer having a low glass transition temperature is used. Even if it exists, it is possible to improve fiber process property.

  In one embodiment of the present invention, a composite fiber excellent in spinnability can be obtained even when the single fiber fineness is low.

  According to the present invention, a composite fiber having excellent flexibility, stretchability, and light resistance can be obtained, and can be suitably used for various applications that require these characteristics.

Sectional drawing which shows the composite form of the composite fiber of this invention. The other sectional view showing the compound form of the conjugate fiber of the present invention. The other sectional view showing the compound form of the conjugate fiber of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail. The conjugate fiber of the present invention comprises an acrylic block copolymer (A) composed of a polymer block (a1) mainly composed of acrylate units and a polymer block (a2) mainly composed of methacrylic ester units. Hereinafter referred to as A component)) and B component which is a readily soluble thermoplastic polymer, and in the fiber cross section, B component is a composite fiber that covers 70% or more of the total circumference of A component. is there. The A component and the B component may be compatible with each other at the interface, but are preferably incompatible with each other.

(Acrylic block copolymer (component A))
The acrylic block copolymer forming the component A of the conjugate fiber of the present invention has at least one polymer block (a1) mainly composed of acrylate units and at least one polymer composed mainly of methacrylic ester units. It is composed of a polymer block (a2). The content of the acrylate ester unit or the methacrylate ester unit in the polymer block (a1) or the polymer block (a2) is not particularly limited as long as it is an amount that is a main component, but is 60 to 100% by mass, respectively. Is preferable, and it is more preferable that it is the range of 80-100 mass%.

  In the acrylic block copolymer (component A), the polymer block (a1) mainly composed of an acrylate unit is a polymer block mainly composed of an acrylate unit, and the polymer block is formed. Examples of the acrylic acid ester include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, Amyl acrylate, Isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, acrylate Kishiechiru, 2-hydroxyethyl acrylate, can be used one or more such as 2-methoxyethyl acrylate, it is not limited to those exemplified above. Among these acrylate esters, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, phenoxyethyl acrylate, 2-acrylate It is preferable to use an acrylic acid alkyl ester such as methoxyethyl, and it is more preferable to use n-butyl acrylate and 2-ethylhexyl acrylate. In addition to the above, as long as the intended effect of the present invention is not lost, glycidyl acrylate, allyl acrylate, methacrylic acid ester, methacrylic acid, acrylic acid, aromatic vinyl compound, acrylonitrile, methacrylonitrile, olefin Other monomers may be used as a copolymerization component (small component).

  In the acrylic block copolymer (component A), the polymer block (a2) mainly composed of methacrylic acid ester units is a polymer block mainly composed of methacrylic acid ester units, and forms the polymer block. Examples of the methacrylic acid ester to be used include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, and tert-butyl methacrylate. , Amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, isobornyl methacrylate, methacrylic acid Eniru, benzyl methacrylate, phenoxyethyl, 2-hydroxyethyl methacrylate, may be used one or more methacrylic acid 2-methoxyethyl, but is not limited to those exemplified above. Among these methacrylates, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate. Is preferred, and methyl methacrylate is more preferred. In addition to the above, as long as the intended effect of the present invention is not lost, glycidyl methacrylate, allyl methacrylate, the acrylic acid ester, methacrylic acid, acrylic acid, aromatic vinyl compound, acrylonitrile, methacrylonitrile, Other monomers such as olefin may be used as a copolymerization component (small amount component).

  The acrylic block copolymer (component A) is composed of a polymer block (a1) mainly composed of acrylate units and a polymer block (a2) mainly composed of methacrylate units. It is preferable to use a triblock copolymer in which the polymer block (a2) is bonded to both ends of the combined block (a1). As long as the initial effects of the present invention are not lost, the polymer block (c) derived from a monomer other than the acrylate monomer and the methacrylic acid ester monomer may be included in a block different from these blocks. Good. The form of the bond between the polymer block (c) and the polymer block (a1) mainly composed of the acrylate unit and the polymer block (a2) mainly composed of the methacrylic ester unit is not particularly limited. , (A2)-{(a1)-(a2)} n- (c) structure (n is a natural number) or (c)-(a2)-{(a1)-(a2)} n- (c) structure Etc. Examples of monomers constituting such a polymer block (c) include olefins such as ethylene, propylene, 1-butene, isobutylene and 1-octene; conjugated diene compounds such as 1,3-butadiene, isoprene and myrcene; Aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; vinyl acetate, vinylpyridine, acrylonitrile, methacrylonitrile, vinyl ketone, vinyl chloride, vinylidene chloride, vinylidene fluoride, acrylamide, methacryl Examples thereof include amide, ε-caprolactone, and valerolactone.

  The molecular chain form of the acrylic block copolymer (component A) is not particularly limited, and may be any of linear, branched, radial, and the like. The weight average molecular weight of the acrylic block copolymer (component A) is not necessarily limited, but is usually in the range of 10,000 to 2,000,000, and in the range of 15,000 to 1,200,000. It is preferable that it exists in. In particular, it is more preferably in the range of 15,000 to 100,000. The weight average molecular weight of the polymer block (a1) mainly composed of acrylate units is not necessarily limited, but is usually in the range of 8,000 to 1,500,000, and 12,000 to 1 In the range of 1,000,000. Furthermore, the weight average molecular weight of the polymer block (a2) mainly composed of methacrylic acid ester units is not necessarily limited, but is usually in the range of 1,000 to 750,000, and 1,500 to 500,000. It is preferable to be in the range.

  Content in the acrylic block copolymer (A component) of the polymer block (a1) mainly composed of an acrylate ester unit constituting the acrylic block copolymer (A component) is 65% by mass or more. It is preferable. It is more preferably 65 to 85% by mass, and particularly preferably 75 to 85% by mass from the viewpoint of improving the spinnability and knitting of the conjugate fiber of the present invention. When the content of the polymer block (a1) mainly composed of an acrylate unit is 90% by mass or more, the composite fiber of the present invention is stuck, which is not preferable as a molding material.

  Further, the molecular weight distribution (Mw / Mn) of the acrylic block copolymer (component A) should be in the range of 1.0 to 2.0, and the content of the low polymer is extremely small. More preferably, it is in the range of .0 to 1.6.

  The acrylic block copolymer (component A) used in the present invention has a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride, or an amino group in the molecular chain or at the molecular chain end as necessary. Also good.

  As a method for producing the acrylic block copolymer (component A) used in the present invention, a method of living polymerization of monomers constituting each block is used. As a technique for such living polymerization, for example, an anionic polymerization is carried out in the presence of a mineral salt such as an alkali metal or alkaline earth metal salt using an organic alkali metal compound as a polymerization initiator (Japanese Patent Publication No. 7-25859). Gazette), an anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (see JP-A-11-335432), a method of polymerizing using an organic rare earth metal complex as a polymerization initiator (special Kaihei 6-93060), radical polymerization in the presence of a copper compound using an α-halogenated ester compound as an initiator (Macromol. Chem. Phys.) 201, 1108-1114 (2000)). Moreover, the method of polymerizing the monomer which comprises each block using a polyvalent radical polymerization initiator and a polyvalent radical chain transfer agent, and manufacturing as a mixture containing the acryl-type block copolymer (A) of this invention, etc. Also mentioned. In these methods, the block copolymer is obtained with high purity and does not contain a high molecular weight material having a narrow molecular weight distribution. Therefore, an anionic polymerization is carried out in the presence of an organic aluminum compound using an organic alkali metal compound as a polymerization initiator. Is preferred. Representative examples of the organoaluminum compound include isobutyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum, isobutyl bis (2,6-di-t-butylphenoxy) aluminum, isobutyl bis [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, n-octylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, n-octylbis (2,6 -Di-t-butylphenoxy) aluminum, n-octylbis [2,2'-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, tris (2,6-di-t-butyl-4-methyl) And phenoxy) aluminum, tris (2,6-diphenylphenoxy) aluminum, and the like. Among them, isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, isobutylbis (2,4-di-t-butylphenoxy) aluminum, n-octylbis (2,6-di-t -Butyl-4-methylphenoxy) aluminum or n-octylbis (2,4-di-t-butylphenoxy) aluminum is particularly preferred from the viewpoint of polymerization activity, block efficiency and the like.

  In addition, the composite fiber of the present invention contains other polymers and additives as required in addition to the acrylic block copolymer (A) as long as the effects of the present invention are not impaired. Also good. Examples of other polymers that can be blended include polyacrylic rubber, polybutene rubber, polyisobutylene rubber, synthetic rubbers such as EPR and EPDM. Examples of additives include mineral oil softeners such as paraffinic oil and naphthenic oil for improving fluidity during molding; carbon dioxide for the purpose of improving heat resistance, weather resistance, etc. Inorganic fillers such as calcium, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate; inorganic fibers or organic fibers such as glass fibers and carbon fibers for reinforcement; heat stabilizers; antioxidants; Light stabilizers; adhesives; tackifiers; plasticizers; antistatic agents; foaming agents. Among these additives, in order to further improve heat resistance and weather resistance, it is practically preferable to add heat stability, an antioxidant, and the like.

(Easily soluble or easily decomposable thermoplastic polymer (component B))
The easily soluble (or easily decomposable) thermoplastic polymer that is the sheath part of the conjugate fiber of the present invention can be melt-spun and is relatively solvent or chemical compared to the thermoplastic resin composition that is the core part. As long as it is easily dissolved or decomposed, any material can be used. Examples of such readily soluble polymers include thermoplastic polymers that can be dissolved and decomposed by water (including warm water), alkalis, acids, and the like, and preferably thermoplastic polyvinyl alcohol that can be dissolved and decomposed in water. And easily soluble polyester polymers that can be dissolved and decomposed in alkali.

  When using a water-soluble thermoplastic polyvinyl alcohol polymer, the polyvinyl alcohol polymer used has a viscosity average polymerization degree of 200 to 500, a saponification degree of 90 to 99.99 mol% (preferably 95 to 99 mol%), Polyvinyl alcohol having a melting point of 160 to 230 ° C. is preferable, and it may be a homopolymer or a copolymer. However, from the viewpoint of melt spinnability, water solubility, and fiber physical properties, it has 4 carbon atoms such as ethylene and propylene. It is preferable to use a copolymerized polyvinyl alcohol modified with 0.1 to 20 mol% (preferably 5 to 15 mol%) with the following α-olefin or the like.

  As the water-soluble thermoplastic polyvinyl alcohol polymer, for example, when immersed in hot water at 100 ° C. at a bath ratio of 1:30, for example, within 60 minutes, preferably within 50 minutes, more preferably within 30 minutes, especially A thermoplastic polyvinyl alcohol polymer that dissolves (decomposes) almost completely within 15 minutes is preferred.

  When using an easily soluble polyester polymer, it is preferable to use a polyester having a high alkali dissolution rate. As the easily soluble polyester polymer, for example, polar group-containing copolymer polyester, aliphatic polyester, and the like can be employed.

As the polar group-containing copolymer polyester, 1 to 5 mol% of ester-forming sulfonic acid metal salt compound (for example, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, etc.), polyalkylene glycol (for example, polypropylene glycol, Examples thereof include copolymer polyesters obtained by copolymerizing 5 to 30% by mass of a poly (C _1-4 alkylene glycol such as polyethylene glycol) and a conventionally used diol component and dicarboxylic acid component.

  Examples of the aliphatic polyester include polylactic acid; a polyester of an aliphatic diol and an aliphatic carboxylic acid such as poly (ethylene succinate), poly (butylene succinate), poly (butylene succinate-co-butylene adipate); Poly (glycolic acid), poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid), poly (6-hydroxycaproic acid) and other polyhydroxycarboxylic acids; poly (ε-caprolactone) and poly (δ-valero) Poly (ω-hydroxyalkanoate) such as lactone). Of these aliphatic polyesters, polylactic acid is preferable, and polylactic acid may be poly D-lactic acid, poly L-lactic acid, or a mixture thereof.

  As the easily soluble polyester polymer, for example, when immersed in a 2% sodium hydroxide aqueous solution at 100 ° C. at a bath ratio of 1:30, for example, within 60 minutes, preferably within 45 minutes, more preferably within 30 minutes, Particularly preferred is an alkali-soluble polyester that dissolves (decomposes) almost completely within 15 minutes.

(Manufacturing method of composite fiber)
The composite fiber of the present invention can be made into a fiber using a conventionally known composite spinning device as long as the combination of the component A and the component B is determined. It can be produced by any spinning method such as a method of drawing after melt spinning at a low speed or a medium speed, a method of direct spinning and spinning at a high speed, and a method of drawing and false twisting simultaneously or subsequently after spinning.

  In the composite fiber of the present invention, the composite ratio of the A component and the B component is preferably such that A: B is 90:10 to 40:60 (mass ratio), more preferably 85:15 to 60:40 (mass). Ratio), and the ratio of the two may be adjusted according to the fiber shape. If the component A is too much, the fiber forming processability, in particular, the occurrence of sticking after fiberizing and winding, may deteriorate the process passability of product production. On the other hand, when there are too many B components, there exists a possibility that the favorable wear feeling to the human body which is aimed at a product cannot be obtained.

  In the cross-section of the conjugate fiber of the present invention, the B component does not need to cover the entire fiber surface, but in order to ensure the winding processability of fiberization, the handleability after winding, and the processability of product production, In the fiber cross section, it is important that the A component is the core and the B component covers 70% to 100% of the total circumference of the A component, more preferably 80% or more, more preferably 90% It is particularly preferable to cover at least%. If it is less than 70%, the yarns are stuck together and cannot be unwound after winding, which is not suitable.

  The composite form of the present invention may be a concentric type, an eccentric type, or a multi-core type as long as the B component can be dissolved and removed by alkali treatment, water treatment, etc., and the A component does not crack. A core-sheath type composite structure in which the A component is a core component and the B component is a sheath component as shown in FIG. 1, and a composite structure in which the B component is intermittently covered around the A component as shown in FIG. A composite structure in which the B component covers the triangular A component as shown in FIG. In addition, the fiber cross-sectional shape of the component A may be a circular cross-sectional shape, or may be an irregular cross-sectional shape such as a triangle, a flat shape, or a multi-leaf type. Further, it is possible to provide a hollow portion inside the component A as shown in FIG. 4, and there is no problem even if it has various cross-sectional shapes such as a hollow shape such as a hollow with a single hole or a hollow with two or more holes. Among these, the composite fiber preferably has a core-sheath type composite structure in which the A component is a core component and the B component is a sheath component.

  The single fiber fineness of the conjugate fiber of the present invention can be set as appropriate according to the application, but can be set in the range of, for example, 0.3 to 50 dtex (preferably 0.3 to 40 dtex), and the fineness is reduced. In the case of fine fibers of 0.3 to 10 dtex, preferably 0.3 to 5 dtex.

  The composite fiber of the present invention obtained as described above can be used as various fiber assemblies (fiber structures). Here, examples of the fiber assembly include various woven and knitted fabrics and fabrics such as nonwoven fabrics.

  In addition, the final product (namely, the cloth which consists of acrylic block copolymers) used with respect to a human body can be obtained by removing B component from these fiber aggregates normally.

  For example, a fabric comprising such an acrylic block copolymer includes a preparation step for preparing the conjugate fiber, a conjugate fiber fabric preparation step for producing a fabric composed of conjugate fibers using the fibers, It can be obtained by a production method including a removing step of removing a B component from a fabric to obtain a fabric made of an acrylic block copolymer.

  The composite fiber fabric may be formed of the composite fiber of the present invention alone, but a woven or knitted fabric or non-woven fabric made of a part of the composite fiber of the present invention, such as natural fiber, chemical fiber, synthetic fiber, etc. It may be a cross-woven fabric with other fibers such as a fiber, a blended yarn, a woven or knitted fabric used as a blended yarn, a blended cotton nonwoven fabric, or the like. For example, when used in combination with other fibers, the proportion of the component A of the composite fiber of the present invention in the woven or knitted fabric or nonwoven fabric may be, for example, 14% by mass or more, preferably 15% by mass or more, preferably It may be 18% by mass or more, more preferably 23% by mass or more. When used as a blended yarn or a blended yarn, the proportion of the component A in the yarn may be, for example, 14 to 95% by mass, preferably 20% by mass or more, preferably 30% by mass or more, and more preferably. 40 mass% or more may be sufficient.

  The fabric made of the composite fiber fabric or the acrylic block copolymer may be subjected to a raising process such as raising a needle cloth or other finishing process as necessary after passing through the fabric forming step.

  The fiber of the present invention can be used as a long fiber, or can be cut as appropriate and used as a short fiber. And since fabrics, such as a woven fabric, a knitted fabric, and a nonwoven fabric, can be manufactured, it uses suitably for various textiles.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by this. In addition, unless otherwise indicated, the part and% in an Example are related with mass.

In the following examples and comparative examples, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of each acrylic block copolymer are determined by gel permeation chromatography (hereinafter referred to as GPC) in terms of polystyrene equivalent molecular weight. From this, the molecular weight distribution (Mw / Mn) was calculated. Moreover, the composition ratio of each polymer block in each acrylic block copolymer was determined by ¹ H-NMR ( ¹ H-nuclear magnetic resonance) measurement.

The measurement apparatus and conditions used above are as follows.
GPC:
Equipment: Tosoh GPC equipment "HLC-8020"
Separation column: “TSKgel GMHXL”, “G4000HXL” and “G5000HXL” connected in series by Tosoh Corporation Eluent: Tetrahydrofuran Eluent flow rate: 1.0 ml / min Column temperature: 40 ° C.
Detection method: differential refractive index (RI)
¹ H-NMR:
Device: JEOL Nuclear Magnetic Resonance Device “JNM-LA400”
Deuterated solvent: Deuterated chloroform

[B component outer periphery coverage in fiber cross section]
From the fiber cross-sectional photograph, for 10 randomly selected filaments, the following formula is used to calculate the percentage (coverage) of the coating section length with respect to the fiber cross-section outer periphery length, and the average value of the coverage of each filament is obtained. It was.
Peripheral coverage ratio of component B (%) = {(fiber cross-section outer periphery length) − (length of the portion exposed on the surface of the outer periphery of component A)} / (fiber cross-section outer periphery length) × 100

[Spinnability evaluation method]
Evaluation was made based on the occurrence of fluff and breakage when spinning 100 kg, and the occurrence of fluff and breakage when 1 kg of spinning yarn was unwound.
◎: No fluff / breakage during spinning, no fluff / breakage during unwinding ○: No fluff / breakage during spinning, 1 occurrence of fluff / breakage during unwinding △: During spinning 1 to 2 times of fluff and yarn breakage, 2 to 5 times of occurrence of fluff and yarn during unwinding ×: 3 times or more of fluff and yarn during spinning, occurrence of fluff and yarn during unwinding 6 times or more

[Evaluation method of knitting property]
The evaluation was based on the occurrence of fluff and yarn breakage during 10 kg knitting.
◎: Good with no fluff and breakage ○: Good with less than 2 occurrences of fluff and breakage △: Appearance of fluff and breakage is recognized 2 to 5 times ×: Generation of fluff and breakage 6 times or more

[Method for evaluating light resistance]
After 80 hours of irradiation with a fade meter, the color change by visual observation and the tensile strength retention after irradiation were determined. Tensile strength retention was determined by the following equation.
Tensile strength retention rate (%) = (G1 / G0) × 100
G0: Tensile strength before irradiation G1: Tensile strength after irradiation

[Evaluation method of stain resistance (color transfer)]
From the obtained composite fiber, a circular knitted fabric was produced using a circular knitting machine (28 gauge), and then dyed and evaluated according to JIS L0844 B-1 (first attached fabric nylon). .
1) Dyeing conditions Temperature × Time = 130 ° C. × 40 minutes Bath ratio = 1: 30
Dye: Dianix Navy Blue SPH (manufactured by DyStar) 5% owf
Dispersant: Disper TL (manufactured by Meisei Chemical Co., Ltd.) 1 g / l
Acetic acid (50%) 1cc / l
2) Reducing cleaning conditions Temperature × Time = 80 ° C. × 20 minutes Bath ratio = 1: 30
Hydrosulfite 1g / l
Sodium hydroxide 1g / l
Amiradine D (Daiichi Kogyo Seiyaku Co., Ltd.) 1g / l

[Evaluation method of acid resistance]
Tensile strength retention after acid treatment was determined. Tensile strength retention was determined by the following equation.
Tensile strength retention rate (%) = (G1 / G0) × 100
G0: Tensile strength before acid treatment G1: Tensile strength after acid treatment As an acid treatment method, “UR mini color” manufactured by Texam Giken Co., Ltd. was used, bath ratio = 1: 50, maleic acid 2 g / L, temperature It processed at 100 degreeC for 30 minutes.

(Reference Example 1) [Synthesis of acrylic block copolymer (A-1)]
A two-liter three-necked flask was fitted with a three-way cock, and the inside was deaerated and replaced with nitrogen. Then, at room temperature, 1040 g of dry toluene, 100 g of 1,2-dimethoxyethane, 30 g of toluene solution containing 21 mmol of (t-butyl-4-methylphenoxy) aluminum was added, and 8.0 mmol of sec-butyllithium was further added. To this was added 52 g of methyl methacrylate and reacted at room temperature for 1 hour, and then 0.1 g of the reaction solution was collected. This is designated as sampling sample 1. Subsequently, the internal temperature of the polymerization solution was cooled to −25 ° C., and 347 g of n-butyl acrylate was added dropwise over 2 hours. After completion of dropping, 0.1 g of the reaction solution was collected. This is designated as sampling sample 2. Subsequently, 52 g of methyl methacrylate was added, and the reaction solution was returned to room temperature and stirred for 8 hours. The polymerization was stopped by adding 4 g of methanol to the reaction solution. The reaction solution after termination of the polymerization was poured into a large amount of methanol to obtain a deposited precipitate. This is designated as sampling sample 3. ¹ H-NMR measurement and GPC measurement were performed using sampling samples 1 to 3, and based on the results, Mw (weight average molecular weight), Mw / Mn (molecular weight distribution), methyl methacrylate polymer (PMMA) block and When the mass ratio of the n-butyl acrylate polymer (PnBA) block and the like were determined, the finally obtained precipitate was a PMMA block-PnBA block-PMMA block triblock copolymer (PMMA-b- PnBA-b-PMMA), Mw of the PMMA block portion is 8,900, Mw / Mn is 1.13, and Mw of the whole triblock copolymer is 76,000, Mw / Mn is 1.24, and the ratio of each polymer block is PMMA (12% by mass) -PnBA (76% by mass) -PMMA (12% by mass). found.

(Reference Example 2) [Synthesis of acrylic block copolymer (A-2)]
A two-liter three-necked flask was fitted with a three-way cock, and the inside was deaerated and replaced with nitrogen. Then, at room temperature, 1040 g of dry toluene, 100 g of 1,2-dimethoxyethane, and isobutyl bis (2,6-di- 66 g of toluene solution containing 46 mmol of (t-butyl-4-methylphenoxy) aluminum was added, and 10 mmol of sec-butyllithium was further added. To this, 68 g of methyl methacrylate was added and reacted at room temperature for 1 hour, and then 0.1 g of the reaction solution was collected. This is designated as sampling sample 4. Subsequently, the internal temperature of the polymerization solution was cooled to −25 ° C., and 315 g of n-butyl acrylate was added dropwise over 2 hours. After completion of dropping, 0.1 g of the reaction solution was collected. This is designated as sampling sample 5. Subsequently, 68 g of methyl methacrylate was added, and the reaction solution was returned to room temperature and stirred for 8 hours. The polymerization was stopped by adding 4 g of methanol to the reaction solution. The reaction solution after termination of the polymerization was poured into a large amount of methanol to obtain a deposited precipitate. This is designated as sampling sample 6. ¹ H-NMR measurement and GPC measurement were performed using sampling samples 4 to 6, and based on the results, Mw (weight average molecular weight), Mw / Mn (molecular weight distribution), methyl methacrylate polymer (PMMA) block and When the mass ratio of the n-butyl acrylate polymer (PnBA) block and the like were determined, the finally obtained precipitate was a PMMA block-PnBA block-PMMA block triblock copolymer (PMMA-b- PnBA-b-PMMA), Mw of the PMMA block part is 9,700, Mw / Mn is 1.08, and Mw of the whole triblock copolymer is 77,000, Mw / Mn is 1.19, and the ratio of each polymer block is PMMA (15 mass%)-PnBA (70 mass%)-PMMA (15 mass%). found.

(Reference Example 3) [Synthesis of acrylic block copolymer (A-3)]
A two-liter three-necked flask was fitted with a three-way cock, and the inside was deaerated and replaced with nitrogen. Then, at room temperature, 1040 g of dry toluene, 100 g of 1,2-dimethoxyethane, and isobutyl bis (2,6-di- 17 g of a toluene solution containing 12 mmol of t-butyl-4-methylphenoxy) aluminum was added, and 3.6 mmol of sec-butyllithium was further added. To this, 68 g of methyl methacrylate was added and reacted at room temperature for 1 hour, and then 0.1 g of the reaction solution was collected. This is designated as sampling sample 7. Subsequently, the internal temperature of the polymerization solution was cooled to −25 ° C., and 315 g of n-butyl acrylate was added dropwise over 2 hours. After completion of dropping, 0.1 g of the reaction solution was collected. This is designated as sampling sample 8. Subsequently, 68 g of methyl methacrylate was added, and the reaction solution was returned to room temperature and stirred for 8 hours. The polymerization was stopped by adding 4 g of methanol to the reaction solution. The reaction solution after termination of the polymerization was poured into a large amount of methanol to obtain a deposited precipitate. This is designated as sampling sample 9. ¹ H-NMR measurement and GPC measurement are performed using sampling samples 7 to 9, and based on the results, Mw (weight average molecular weight), Mw / Mn (molecular weight distribution), methyl methacrylate polymer (PMMA) block and When the mass ratio of the n-butyl acrylate polymer (PnBA) block and the like were determined, the finally obtained precipitate was a PMMA block-PnBA block-PMMA block triblock copolymer (PMMA-b- PnBA-b-PMMA), Mw of the PMMA block part is 23,000, Mw / Mn is 1.08, and Mw of the whole triblock copolymer is 146,000, Mw / Mn is 1.35, and the ratio of each polymer block is PMMA (15 mass%)-PnBA (70 mass%)-PMMA (15 mass%). It turned out.

Example 1
As an acrylic block copolymer (component A), a block copolymer having a triblock structure of “polymethyl methacrylate” — “n-butyl polyacrylate” — “polymethyl methacrylate” in Reference Example 1 (A -1) (Mw: 76,000, Mw / Mn: 1.24, methyl methacrylate unit content: 23% by mass), on the other hand, as component B, 8% by mass of polyethylene glycol having a molecular weight of 2000 and 5-sodium sulfo Using polyethylene terephthalate having an intrinsic viscosity [η] of 0.52 copolymerized with 5 mol% of isophthalic acid, the composite ratio of component A and component B was 75:25, and each was melted in a separate extruder. The composite fiber shown by the cross section shown in FIG. 1 was discharged from the composite spinning nozzle.

  Next, after the yarn discharged from the spinneret was cooled by a horizontal blowing type cooling air device having a length of 1.0 m, it was continuously installed at a position of 1.3 m from directly below the spinneret and an inner diameter of 1.0 m. After introducing into a 30 mm tube heater (inner wall temperature: 180 ° C.) and drawing in the tube heater, an oil agent is applied to the fiber coming out of the tube heater, and subsequently at a take-up speed of 3000 m / min via a roller. The composite fiber of 111 dtex / 24 filament was manufactured by winding. A circular knitted fabric was produced from the obtained composite fiber using a circular knitting machine (28 gauge). After scouring this knitted fabric, it is immersed in an alkaline aqueous solution (solution temperature 100 ° C.) of caustic soda 20 g / L and a bath ratio of 1:30 for 30 minutes to selectively dissolve and remove the B component. A circular knitted fabric made of the polymer (A-1) was obtained. Each evaluation result is as shown in Table 1.

(Example 2)
Except that the composite ratio of the A component and the B component of the composite fiber was changed as shown in Table 1, fiberization and production of a knitted fabric and dissolution and removal of the B component were performed in the same manner as in Example 1, thereby obtaining an acrylic system. A circular knitted fabric made of the block copolymer (A-1) was obtained and evaluated. Each evaluation result is as shown in Table 1.

Example 3
Fibrosis and production of knitted fabric, B component in the same manner as in Example 1 except that the same polymer as in Example 1 was used as the A component and polylactic acid (6200D manufactured by Cargill Dow, Inc.) was used as the B component. A circular knitted fabric made of an acrylic block copolymer (A-1) was obtained and evaluated. Each evaluation result is as shown in Table 1.

(Example 4)
The same polymer as in Example 1 was used as the A component, and thermoplastic modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., saponification degree: 98.5, ethylene content 8.0 mol%, polymerization degree: 380) was used as the B component. Except for the above, fiberization was carried out in the same manner as in Example 1, and a knitted fabric was produced in the same manner. Thereafter, the knitted fabric was treated in hot water at 100 ° C. with a bath ratio of 1:30 for 40 minutes to dissolve and remove the component B, thereby obtaining a circular knitted fabric made of an acrylic block copolymer (A-1). Each evaluation result is as shown in Table 1.

(Examples 5-6)
Except that the cross-sectional shape of the fiber was changed as shown in Table 1, fiberization, production of a knitted fabric, and dissolution and removal of the B component were carried out in the same manner as in Example 1, so that an acrylic block copolymer (A-1 ) Was obtained and evaluated. Each evaluation result is as shown in Table 1. In Examples 5 to 6, fiber formation was performed using a modified nozzle for the spinneret.

(Example 7)
As a component A, a block copolymer (A-2) having a triblock structure of “polymethyl methacrylate”-“poly-n-butyl acrylate”-“polymethyl methacrylate” in Reference Example 2 (Mw: 77, 000, Mw / Mn: 1.19, methyl methacrylate unit content: 30% by mass), on the other hand, as component B, 8% by mass of polyethylene glycol having a molecular weight of 2000 and 5 mol% of 5-sodium sulfoisophthalic acid were copolymerized. Polyethylene terephthalate having an intrinsic viscosity [η] of 0.52 is used, and the composite ratio of component A and component B is set to a mass ratio of 75:25. Each is melted by a separate extruder, and is shown by the cross section shown in FIG. The composite fiber was discharged from the composite spinning nozzle. A circular knitted fabric was produced from the obtained composite fiber using a circular knitting machine (28 gauge). After scouring this knitted fabric, it is immersed in an alkaline aqueous solution (solution temperature 100 ° C.) of caustic soda 20 g / L and a bath ratio of 1:30 for 30 minutes to selectively dissolve and remove the B component. A circular knitted fabric made of the polymer (A-2) was obtained. Each evaluation result is as shown in Table 1.

(Example 8)
As a component A, a block copolymer (A-3) having a triblock structure of “polymethyl methacrylate”-“poly-n-butyl acrylate”-“polymethyl methacrylate” in Reference Example 3 (Mw: 146 000; Mw / Mn: 1.35; methyl methacrylate unit content: 30% by mass). On the other hand, as component B, 8% by mass of polyethylene glycol having a molecular weight of 2000 and 5 mol% of 5-sodium sulfoisophthalic acid were copolymerized. Using polyethylene terephthalate having an intrinsic viscosity [η] of 0.52, the composite ratio of component A and component B is set to a mass ratio of 3: 1, and each is melted by a separate extruder, and is shown by the cross section shown in FIG. The composite fiber was discharged from the composite spinning nozzle. A circular knitted fabric was produced from the obtained composite fiber using a circular knitting machine (28 gauge). After scouring this knitted fabric, it is immersed in an alkaline aqueous solution (solution temperature 100 ° C.) of caustic soda 20 g / L and a bath ratio of 1:30 for 30 minutes to selectively dissolve and remove the B component. A circular knitted fabric made of the polymer (A-3) was obtained. Each evaluation result is as shown in Table 1.

(Comparative Example 1)
A circular knitted fabric was prepared by using a polyurethane fiber ("Roika" 20T1 manufactured by Asahi Kasei Fibers) using a circular knitting machine (28 gauge), and the obtained circular knitted fabric was evaluated. Each evaluation result is as shown in Table 1, and was inferior to the present invention in all points of light resistance, stain resistance and acid resistance.

(Comparative Example 2)
Fiber formation was attempted in the same manner as in Example 1 except that the component B was not used and the composite fiber was not used. However, the fiber forming processability was remarkably deteriorated due to poor unwinding due to agglutination, and fibers could not be obtained.

(Comparative Example 3)
Using the same polymer as in Example 1, the A component and the B component are compound-spun in a side-by-side manner, and in the fiber cross section, the A component is the core and the B component covers 50% of the total circumference of the A component. Except for this, fiberization was attempted in the same manner as in Example 1. However, the obtained fiber has insufficient spinnability, particularly inferior knitting property, and a circular knitted fabric could not be produced.

  In the case of long fibers, the main use of the conjugate fiber of the present invention can be used as a clothing material in which a woven or knitted fabric or the like is produced singly or in part to develop a good wearing feeling. Such clothing materials include swimwear, lingerie, foundation, underwear, sportswear, etc., pantyhose, socks such as socks, supporters, bandages, masks, masking cloths, taping, etc., automotive seats In the case of short fibers, they can be used as staples for clothing, dry nonwoven fabrics, wet nonwoven fabrics, etc. It can also be used for non-clothing applications such as cleaning fabrics, filter materials, various living materials, and industrial materials.

  As described above, the preferred embodiment of the present invention has been described. However, those skilled in the art will readily consider various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

1: A component of composite fiber 2: B component of composite fiber

Claims (7)

An acrylic block copolymer (component A) composed of a polymer block (a1) consisting of an acrylate unit and a polymer block (a2) consisting of a methacrylic ester unit, and a readily soluble or easily decomposable thermoplastic A composite fiber composed of a polymer (component B), wherein the composite ratio (mass ratio) of component A and component B is A: B = 90: 10: 40: 60, and the component A is A composite fiber that is a core and covers 70% or more of the total circumference of the A component by the B component.   The content of the polymer block (a1) in the component A is 65% by mass or more, and the ratio (Mw / Mn) of the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the component A is 1.0 to 1. The composite fiber according to claim 1, which is .6.   The composite fiber according to claim 1 or 2, wherein the component A is a triblock copolymer in which the polymer block (a2) is bonded to both ends of the polymer block (a1).   The composite fiber according to any one of claims 1 to 3, wherein the component B is formed of at least one selected from a thermoplastic polyvinyl alcohol polymer and a readily soluble polyester.   The composite fiber according to any one of claims 1 to 4, wherein the single fiber fineness is 0.3 to 50 dtex. The composite fiber according to any one of claims 1 to 5 , which has a core-sheath structure in which the A component is a core component and the B component is a sheath component. A preparation step for preparing the conjugate fiber according to any one of claims 1 to 6 , a conjugate fiber fabric production step for producing a fabric composed of conjugate fiber using the conjugate fiber, and B to B A method for producing an acrylic block copolymer fabric, comprising removing a component to obtain an acrylic block copolymer fabric.

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