WO2023058563A1 - 液晶ポリエステル繊維およびその製造方法 - Google Patents

液晶ポリエステル繊維およびその製造方法 Download PDF

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Publication number
WO2023058563A1
WO2023058563A1 PCT/JP2022/036593 JP2022036593W WO2023058563A1 WO 2023058563 A1 WO2023058563 A1 WO 2023058563A1 JP 2022036593 W JP2022036593 W JP 2022036593W WO 2023058563 A1 WO2023058563 A1 WO 2023058563A1
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Prior art keywords
liquid crystalline
crystalline polyester
polyester fiber
fiber
liquid crystal
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PCT/JP2022/036593
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English (en)
French (fr)
Japanese (ja)
Inventor
幸広 寺本
拓哉 辻本
英樹 鎌田
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Kuraray Co Ltd
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Kuraray Co Ltd
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Priority to EP22878432.8A priority Critical patent/EP4414486A4/en
Priority to US18/699,015 priority patent/US20240417511A1/en
Priority to JP2023552844A priority patent/JP7714669B2/ja
Priority to CN202280067596.XA priority patent/CN118076770A/zh
Priority to KR1020247013123A priority patent/KR20240056782A/ko
Publication of WO2023058563A1 publication Critical patent/WO2023058563A1/ja
Anticipated expiration legal-status Critical
Priority to JP2025119507A priority patent/JP2025143512A/ja
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
    • C08G63/065—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids the hydroxy and carboxylic ester groups being bound to aromatic rings
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
    • D01F6/84—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from copolyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/08—Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D1/00—Treatment of filament-forming or like material
    • D01D1/04—Melting filament-forming substances
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/08—Melt spinning methods
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters
    • D01F6/625—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters derived from hydroxy-carboxylic acids, e.g. lactones
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B29K2067/04—Polyesters derived from hydroxycarboxylic acids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0041—Crystalline
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0077—Yield strength; Tensile strength
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2250/00—Compositions for preparing crystalline polymers
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2331/00—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products
    • D10B2331/04—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products polyesters, e.g. polyethylene terephthalate [PET]
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2401/00—Physical properties
    • D10B2401/06—Load-responsive characteristics
    • D10B2401/062—Load-responsive characteristics stiff, shape retention
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2401/00—Physical properties
    • D10B2401/06—Load-responsive characteristics
    • D10B2401/063—Load-responsive characteristics high strength
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2505/00—Industrial
    • D10B2505/02—Reinforcing materials; Prepregs
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2505/00—Industrial
    • D10B2505/12—Vehicles

Definitions

  • the present invention relates to a liquid crystal polyester fiber and a method for producing the same.
  • thermoplastic fibers in the case of intermediate materials for fiber-reinforced composite materials, the thermoplastic fibers are heat-sealed in a post-process, so hereinafter referred to as fusion (sometimes referred to as fibers) are known.
  • Patent Document 1 Japanese Unexamined Patent Publication No. 1-280031 discloses a method for producing a flexible composite fiber useful for composite products, which consists of combining a reinforcing multifilament and a thermoplastic multifilament in layers. ing.
  • Patent Document 2 Japanese Patent Application Laid-Open No.
  • Patent Document 3 Japanese Patent Application Laid-Open No. 4-732257 discloses a method for producing a mixed yarn for a thermoplastic composite of continuous thermoplastic fibers and continuous reinforcing fibers.
  • Composite yarns containing such continuous reinforcing fibers and continuous thermoplastic fibers are generally used as precursors for fiber-reinforced composite materials. It is more flexible than intermediate materials made by melting and impregnating thermoplastic resin into reinforced fiber tows and fabrics, and can be shaped into various shapes such as cylindrical and dome shapes by weaving and knitting. It is easy to form a fabric with a large three-dimensional deformation. Therefore, it can be effectively used as a raw material for sheet-like fiber-reinforced moldings having three-dimensional features such as duct tubes and automobile bumpers.
  • liquid crystal polyester fibers made of liquid crystal polyester which is a thermoplastic resin with excellent vibration damping properties, are used.
  • a reinforcing fiber or fusible fiber it can be expected that a molded article having excellent damping properties can be obtained.
  • liquid crystalline polyester fibers are used as fusible fibers
  • thermal decomposition gas is generated from the liquid crystalline polyester fibers when heated to a temperature at which fusion processing is possible, and many bubbles are formed inside and on the surface of the resulting fiber-reinforced molding.
  • the object of the present invention is to provide a liquid crystalline polyester fiber that does not generate air bubbles when used as a fusible fiber and is heat fused, and that can be used to produce a molded product with excellent hue.
  • the inventors of the present invention made intensive studies to achieve the above object, and found that the thermal decomposition gas generated from the liquid crystalline polyester fiber when heated to a predetermined temperature is at the end of the liquid crystalline polyester constituting the liquid crystalline polyester fiber. It was found that when a carboxy group is present, the occurrence of decarboxylation at the carboxy group is the trigger. Furthermore, the liquid crystal polyester constituting the liquid crystal polyester fiber contains ketone bonds generated by a side reaction, and the ketone bond affects the hue of the liquid crystal polyester fiber, which led to the completion of the present invention. .
  • the total carboxy terminal content is 5.0 meq/kg or less (preferably 4.0 meq/kg or less, more preferably 3.0 meq/kg or less, still more preferably 2.5 meq/kg or less, still more preferably 2.0 meq/kg or less) and a ketone bond amount of 0.05 mol% or less (preferably 0.04 mol% or less, more preferably 0.03 mol% or less).
  • a method for producing a liquid crystalline polyester fiber comprising at least: [Aspect 7]
  • the heat history TH represented by the following formula (1) is 250 to 1100 (preferably 300 to 1000, more preferably 350 to 950, more preferably 400 ⁇ 900), a method for producing a liquid crystal polyester fiber.
  • Mp 0 is the melting point (° C.) of the liquid crystalline polyester
  • x 1, 2, ... during residence
  • T x (T 1 , T 2 , . is the heating temperature (° C.) of
  • y is the residence time (minutes) in the heating temperature region where T x ⁇ (Mp 0 +10) after the input.
  • M and y are not integers, they are rounded off and calculated as integers
  • M is an integer that satisfies M ⁇ y+1.
  • liquid crystalline polyester fiber of the present invention it is possible to suppress the generation of gas during heating and melting, and it is possible to produce a molded product with few air bubbles and excellent hue.
  • the liquid crystalline polyester fiber of the present invention is composed of liquid crystalline polyester.
  • the liquid crystalline polyester includes structural units derived from, for example, an aromatic diol, an aromatic dicarboxylic acid, an aromatic hydroxycarboxylic acid, and the like, and unless the effects of the present invention are impaired, an aromatic diol, an aromatic dicarboxylic acid, an aromatic hydroxy
  • the structural unit derived from carboxylic acid is not particularly limited in its chemical constitution.
  • the liquid crystalline polyester may contain structural units derived from aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids to the extent that the effects of the present invention are not impaired.
  • preferred structural units include those shown in Table 1.
  • Y in the formula is independently a hydrogen atom, a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (e.g., alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, isopropyl group, t-butyl group, etc.), alkoxy group (e.g., methoxy group, ethoxy group, isopropoxy group, n-butoxy group, etc.), aryl group (e.g., phenyl group, naphthyl group, etc.), aralkyl group (e.g., benzyl group (phenylmethyl group), phenethyl group (phenylethyl group), etc.), aryloxy groups (eg, phenoxy group), aralkyloxy groups (eg, phenoxy group), aralkyloxy groups (eg, phen
  • More preferred structural units include structural units described in Examples (1) to (18) shown in Tables 2, 3 and 4 below.
  • the structural unit in the formula is a structural unit capable of exhibiting multiple structures, two or more of such structural units may be combined and used as a structural unit that constitutes the polymer.
  • n is an integer of 1 or 2
  • Y 1 and Y 2 are each independently a hydrogen atom, a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), an alkyl group (e.g., methyl group, ethyl group, isopropyl group, t-butyl group, etc.) Alkyl groups having 1 to 4 carbon atoms, etc.), alkoxy groups (e.g., methoxy, ethoxy, isopropoxy, n-butoxy, etc.), aryl groups (e.g., phenyl, naphthyl, etc.), aralkyl groups (e.g., , benzyl group (phenylmethyl group), phenethyl group (phenylethyl group), etc.), aryl
  • Z includes a substituent represented by the following formula.
  • the liquid crystalline polyester may preferably be a combination having a naphthalene skeleton as a structural unit. It is particularly preferred to contain both structural units (A) derived from hydroxybenzoic acid and structural units (B) derived from hydroxynaphthoic acid.
  • the structural unit (A) includes the following formula (A)
  • the structural unit (B) includes the following formula (B).
  • the ratio of units (B) may preferably range from 9/1 to 1/1, more preferably from 7/1 to 1/1, even more preferably from 5/1 to 1/1.
  • the total amount of the structural units (A) and the structural units (B) may be, for example, 65 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% of all structural units. % or more. Liquid crystalline polyesters containing 4 to 45 mol % of the constituent units of (B) in the polymer are particularly preferred.
  • the liquid crystalline polyester contains a structural unit derived from 4-hydroxybenzoic acid as an aromatic hydroxycarboxylic acid, and may contain a structural unit derived from an aromatic dicarboxylic acid and a structural unit derived from an aromatic diol.
  • a structural unit derived from an aromatic dicarboxylic acid may contain at least one selected from the group consisting of the following formula (C) and the following formula (D) as a structural unit derived from an aromatic dicarboxylic acid, and as a structural unit derived from an aromatic diol, the following formula At least one selected from the group consisting of (E) and formula (F) below may be used.
  • a liquid crystal polyester comprising a structural unit (D) derived from an acid (formula (D) below) and a structural unit (E) derived from 4,4'-dihydroxybiphenyl as an aromatic diol (formula (E) below),
  • the liquid crystalline polyester may contain structural units derived from 4-hydroxybenzoic acid, preferably 50 mol% or more, more preferably 53 mol% or more, still more preferably 60 mol% or more.
  • the upper limit of the content of structural units derived from 4-hydroxybenzoic acid in the liquid crystal polyester is not particularly limited, but may be, for example, 90 mol% or less, preferably 88 mol% or less, more preferably 85 mol%. It may be below.
  • the melting point (hereinafter sometimes referred to as Mp 0 ) of the liquid crystalline polyester used in the present invention is preferably in the range of 250 to 380°C, more preferably 255 to 370°C, still more preferably 260 to 360°C. may Further, the melting point of the liquid crystalline polyester may be more preferably 250 to 330° C., still more preferably 260 to 320° C. from the viewpoint of using the obtained liquid crystalline polyester fiber as a fusible fiber.
  • the melting point referred to here is the main absorption peak temperature measured and observed with a differential scanning calorimeter (DSC; "TA3000" manufactured by Mettler Co., Ltd.) in accordance with JIS K 7121 test method.
  • the liquid crystalline polyester fiber contains thermoplastic polymers such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyamide, polyphenylene sulfide, polyether ether ketone, and fluororesin within a range that does not impair the effects of the present invention. good too.
  • various additives such as inorganic substances such as titanium oxide, kaolin, silica, and barium oxide, carbon black, colorants such as dyes and pigments, antioxidants, ultraviolet absorbers, and light stabilizers may be included.
  • the liquid crystalline polyester fiber of the present invention may contain a metal catalyst acting on the decarboxylation reaction of the aromatic carboxylic acid. It may be less than ppm by weight, preferably less than 5 ppm by weight, more preferably less than 1 ppm by weight.
  • the liquid crystalline polyester fiber of the present invention may contain 50% by weight or more of the liquid crystalline polyester, preferably 80% by weight or more, more preferably 90% by weight or more, still more preferably 95% by weight or more, and even more preferably 99% by weight. .9% by weight or more may be contained.
  • the liquid crystalline polyester fiber of the present invention has a total carboxy terminal content (total CEG content) of 5.0 meq/kg or less.
  • the total amount of CEG means the amount of carboxyl groups present at the ends of the molecules constituting the liquid crystal polyester fiber per 1 kg of the liquid crystal polyester fiber, and is a value measured by the method described in Examples below. be.
  • the carboxy group present at the polymer terminal in the liquid crystalline polyester a structural unit derived from a monomer having a carboxy group such as an aromatic hydroxycarboxylic acid or an aromatic dicarboxylic acid forms the polymer terminal. It may be a carboxy group remaining unreacted in a structural unit present at the end of the polymer.
  • the liquid crystalline polyester fiber of the present invention preferably has a total CEG content of 4.0 meq/kg or less, more preferably 3.0 meq/kg or less, and still more preferably 2.5 meq. /kg or less, even more preferably 2.0 meq/kg or less.
  • the lower limit of the total CEG amount is not particularly limited, it may be, for example, 0.1 meq/kg or more.
  • the liquid crystal polyester fiber of the present invention has a ketone bond amount of 0.05 mol% or less.
  • the amount of ketone bonds means the ratio of the molar amount of ketone bonds to the total molar amount of ester bonds and ketone bonds (molar amount of ketone bonds/(molar amount of ester bonds + molar amount of ketone bonds)). and is a value measured by the method described in Examples below.
  • the inventors of the present invention found that when a liquid crystal polyester resin is melt-processed, a ketone bond is formed from an ester bond due to a side reaction, and that the ketone bond affects the hue of the liquid crystal polyester fiber.
  • the liquid crystalline polyester fiber of the present invention suppresses the formation of ketone bonds.
  • the ketone bond amount may be preferably 0.04 mol % or less, more preferably 0.03 mol % or less.
  • the lower limit of the ketone bond amount is not particularly limited, it may be, for example, 0.005 mol % or more.
  • liquid crystal polyester fibers can exhibit extremely high mechanical properties by increasing the molecular weight of the polymer by heat-treating the spun raw yarn obtained by melt spinning and solid phase polymerization.
  • the liquid crystalline polyester fiber of the present invention may be a spun yarn, or may be a heat-treated yarn obtained by solid phase polymerization within a range that does not impair the effects of the present invention.
  • the melting point (Mp) of the liquid crystalline polyester fiber is raised from the melting point (Mp) of the raw yarn by solid state polymerization
  • the liquid crystalline polyester fiber of the present invention is preferably a raw yarn when used as a fusible fiber. .
  • the liquid crystalline polyester fiber of the present invention may have a total end weight of 50 meq/kg or more, preferably 60 meq/kg or more, more preferably 70 meq/kg or more.
  • the total single end weight indicates the number of polymer chains and is used as an index for evaluating molecular weight. Considering that it is difficult to quantify all kinds of terminals depending on the composition of the liquid crystalline polyester, in the present invention, the total amount of one terminal is based on 1 kg of the liquid crystalline polyester fiber.
  • the total amount (meq/kg) of the carboxy group derived from the carboxylic acid and the terminal from which carbon dioxide was eliminated by the decarboxylation reaction was calculated as the molar ratio of the structural unit derived from the hydroxycarboxylic acid to the total structural units in the liquid crystal polyester (hydroxycarboxylic acid It is defined as a numerical value obtained by dividing by (molar amount of acid-derived structural unit/molar amount of all structural units), and is a value measured by the method described in Examples below.
  • the total amount of one end is within the above range, the polymerization of the liquid crystalline polyester does not proceed more than necessary and the molecular weight is relatively low, so that it can be used as a fusible fiber.
  • the upper limit of the total amount of one end is not particularly limited, but if the molecular weight is too low, the strength required for processing the fiber may not be obtained, so for example, it may be 100 meq/kg or less, preferably 90 meq. /kg or less.
  • the liquid crystalline polyester fiber of the present invention does not need to have high strength from the viewpoint of use as a fusible fiber.
  • the strength may be less than 18 cN/dtex, preferably 2 to 16 cN/dtex, more preferably It may be 6 to 12 cN/dtex.
  • the strength of the liquid crystalline polyester fiber refers to tensile strength, which is a value measured by the method described in Examples below.
  • the liquid crystalline polyester fiber of the present invention may have a melting point of 380°C or less, preferably 250 to 350°C, more preferably 260 to 300°C, from the viewpoint of use as a fusible fiber.
  • the melting point of the liquid crystal polyester fiber is a value measured by the method described in Examples below.
  • the single fiber fineness of the liquid crystalline polyester fiber of the present invention can be appropriately selected depending on the application, etc.
  • the single fiber fineness may be 0.5 to 50 dtex, preferably 1.0 to 35 dtex, more preferably. It may be 1.0 to 15 dtex, more preferably 1.5 to 10 dtex.
  • the liquid crystalline polyester fiber of the present invention may be monofilament or multifilament.
  • the number of filaments can be appropriately selected depending on the application, etc.
  • the number of filaments may be 2 to 5000, preferably 3 to 4000, more preferably 5 to 3000.
  • the total fineness of the liquid crystalline polyester fiber of the present invention can be appropriately selected depending on the application and the like. may be from 10 to 600 dtex.
  • the CO 2 gas generation amount measured by the examples described later may be 2.0 mmol/kg or less, preferably 1.5 mmol/kg or less, more preferably 1.0 mmol/kg. /kg or less.
  • the liquid crystalline polyester fiber of the present invention can keep the amount of ketone bonds low, it is excellent in hue. or more.
  • the L * value indicates the L * value representing the lightness of the L * a * b * color system standardized by the Commission Internationale de l'Eclairage (CIE), and is measured by the method described in Examples below. value. The larger the L * value, the brighter the image, and the smaller the value, the darker the image. Although the upper limit of the L * value is not particularly limited, it may be 85 or less, for example.
  • the liquid crystalline polyester fiber of the present invention can reduce the surface roughness of the fiber, probably because the amount of ketone bonds can be kept low.
  • the surface roughness of the liquid crystalline polyester fiber affects the workability when used as a fusible fiber and the adhesiveness to reinforcing fibers, leading to deterioration of physical properties.
  • the surface roughness Ra may be 1.0 ⁇ m or less, preferably 0.8 ⁇ m or less, more preferably 0.6 ⁇ m or less.
  • the lower limit of the surface roughness Ra is not particularly limited, it may be, for example, 0.1 ⁇ m or more.
  • Surface roughness Ra is the arithmetic average roughness measured according to JIS B 0601-2001, and in the roughness curve of the reference length, the unevenness of that section is the absolute deviation from the average line to the roughness curve It is expressed as the average value of the values.
  • the surface roughness Ra is measured by the method described in Examples below.
  • the method for producing the liquid crystalline polyester fiber of the present invention is not particularly limited as long as the total amount of CEG and the amount of ketone bonds in the liquid crystalline polyester fiber can be adjusted to the specific amounts as described above. and a step of discharging the melt-kneaded material from a nozzle and spinning it.
  • the heat history TH represented by the following formula (1) may be 250 to 1100 in the melt-kneading step.
  • Mp 0 is the melting point (° C.) of the liquid crystalline polyester
  • x 1, 2, ...
  • x M is the time (minutes) when the melt-kneaded product is discharged from the nozzle, and T x (T 1 , T 2 , . is the heating temperature (° C.) of , and y is the residence time (minutes) in the heating temperature region where T x ⁇ (Mp 0 +10) after the input.
  • M and y are not integers, they are rounded off and calculated as integers, and M is an integer that satisfies M ⁇ y+1.
  • TH represented by the above formula (1) is a residence time from when the liquid crystalline polyester is put into the extruder until it is discharged from the nozzle as a melt-kneaded product, and the liquid crystalline polyester has a carboxyl at the molecular terminal. It refers to the index of thermal history that indicates the degree of exposure to high temperatures that cause decarboxylation of groups and side reactions of ester bonds.
  • the inventors of the present invention have found that when a liquid crystal polyester fiber has a carboxyl group at the end of the liquid crystalline polyester, when it is used as a fusible fiber and heated, the carboxyl group undergoes a decarboxylation reaction, and carbon dioxide is generated as a pyrolysis gas. found to occur. Therefore, in the manufacturing method of the liquid crystalline polyester fiber, it was found that the decarboxylation reaction of the carboxyl groups at the ends of the molecules can be reduced in advance by melt-kneading in the extruder at high temperatures for a long time, thereby reducing the carboxyl groups at the ends of the molecules. .
  • the inventors have also found that when melt-kneaded for a long time at high temperature, the ester bond of the liquid crystalline polyester undergoes a side reaction to form a ketone bond. Therefore, in the present invention, the heat history of the liquid crystalline polyester is adjusted by adjusting the heating temperature and residence time in relation to its melting point, so that the decarboxylation reaction of the carboxy group at the end of the molecule proceeds while the side reaction of the ester bond occurs. can be suppressed.
  • FIG. 1 is a schematic diagram showing an apparatus 100 used to produce liquid crystalline polyester fibers in accordance with one embodiment of the present invention.
  • the apparatus 100 comprises an extruder 10, a gear pump 30, a spinning head 40, and a pipe 20 connecting them.
  • the extruder 10 includes a hopper 11 into which liquid crystalline polyester is introduced, a barrel 12, a screw 13 rotating inside the barrel 12, and a vent 14.
  • FIG. 1 illustrates the equipment necessary for explaining the method for producing the liquid crystalline polyester fiber of the present invention, the apparatus 100 may be equipped with other equipment as required.
  • the solid liquid crystalline polyester charged from the hopper 11 is transported in the X direction, which is the traveling direction, in the barrel 12 by the rotation of the screw 13, and is heated by a known heater such as a heater installed in the barrel 12. Heated by a heating means. In addition to the heat transfer from the heating means, mechanical energy such as friction and shear is efficiently imparted between the inner wall of the barrel 12 and the screw 13, so that the solid state progresses in the X direction. Liquid crystalline polyester melts. Thereafter, the liquid crystalline polyester in a molten state is metered by a gear pump 30, passed through a pipe 20, transported to a spinning head 40, and discharged through a nozzle 41 at a predetermined spinning temperature. , can produce liquid crystal polyester fiber.
  • the liquid crystalline polyester may be introduced into the extruder 10 as a resin composition containing the above-described thermoplastic polymer, various additives, catalysts, and the like.
  • the heat history of the liquid crystal polyester in the apparatus 100 the heat history that affects the decarboxylation reaction of the carboxy group at the molecular terminal and the side reaction of the ester bond can be grasped by TH represented by the above formula (1).
  • the liquid crystalline polyester is heated as it progresses in the X direction.
  • the heating temperature T x in the device 100 every minute with x being an integer of 1 or more the heating temperature T x is until the residence time M, after the liquid crystalline polyester is put into the extruder 10
  • the temperature of the device 100 at the position of the liquid crystalline polyester after x minutes is shown.
  • the position after x minutes have passed since the injection is indicated by the distance in the X direction that the liquid crystalline polyester is transported in x minutes from the injection position.
  • the distance can be calculated from the volume of the device 100, the transport speed of the screw 13, the transport speed of the gear pump 30, the predetermined time x minutes, and the like.
  • the residence time M is the period from when the liquid crystalline polyester is put into the extruder 10 from the hopper 11 to when the liquid crystalline polyester is discharged from the nozzle 41 as a melt-kneaded product. indicates the dwell time.
  • the residence time M can be calculated from the volume of the entire device 100 from the time the liquid crystalline polyester is charged until it is discharged, the transportation speed of the gear pump 30, etc.
  • the entire device in FIG. 1, the barrel 12 + pipe 20 + gear pump 30 + volume of spinning head 40) [cm 3 ]/ ⁇ (rotation speed of gear pump [RPM] ⁇ transfer capacity per rotation speed of gear pump [cm 3 ]) ⁇ . is rounded off and calculated as an integer.
  • the heating temperature T x does not rise sufficiently with respect to the melting point Mp 0 , and does not affect the heat history.
  • y can be calculated from the volume of the device, the transportation speed of the gear pump, the area set to the low temperature, etc. If it is not an integer, it is rounded off and calculated as an integer.
  • the temperature in the extruder 10 is set to start at a temperature of Mp 0 +10 ° C. or less, and then the set temperature is increased in the X direction. Increase and set the temperature above Mp 0 +10°C.
  • the extruder In addition, from the viewpoint of adjusting the viscosity of the liquid crystalline polyester in a molten state when transported from the extruder 10 toward the spinning head 40, outside the extruder 10 (pipe 20, gear pump 30, and spinning head 40), the extruder Although the temperature may be less than or equal to the maximum temperature in 10, it is preferable to heat at a temperature above Mp 0 +10°C.
  • T x when x is 1 to y satisfies the relationship T x ⁇ (Mp 0 +10)
  • T x when x is y+1 to M is T x > (Mp 0 +10)
  • TH is the sum of T x ⁇ (Mp 0 +10), which is a positive value, for all time x that satisfies the relationship T x >(Mp 0 +10) among the residence times M. It shows summation.
  • T x -(Mp 0 +10) in the above formula (1) is an index of how high the temperature the liquid crystalline polyester is exposed to as a temperature condition that causes the decarboxylation reaction of the carboxy group at the end of the molecule and the side reaction of the ester bond.
  • TH causes a decarboxylation reaction of the carboxy group at the end of the molecule and a side reaction of an ester bond during the residence time from when the liquid crystalline polyester is put into the extruder 10 until it is discharged from the nozzle 41 as a melt-kneaded product. It means an index related to thermal history that shows how much it has been exposed to such high temperatures.
  • TH is too high, that is, if the heating temperature in the extruder is too high and/or the residence time is too long, the side reaction of the ester bonds in the liquid crystalline polyester will occur excessively, and the formation of ketone bonds cannot be suppressed. , the amount of ketone bonds increases, and the hue and surface roughness of the fiber tend to deteriorate.
  • the value of TH is relatively large, the decarboxylation reaction of the terminal carboxyl groups of the liquid crystalline polyester proceeds sufficiently, so that the total amount of CEG becomes small and the amount of gas generated during heating is small.
  • TH when the value of TH is too small, that is, when the heating temperature in the extruder is too low and/or the residence time is too short, the decarboxylation reaction of the carboxy group at the terminal of the liquid crystalline polyester does not easily proceed, and the molecular terminal Carboxy groups cannot be reduced, the total amount of CEG tends to increase, and the amount of gas generated during heating tends to increase. If the value of TH is relatively small, the amount of ketone bonds does not increase, so that the hue and surface roughness of the fiber do not deteriorate.
  • TH may be preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more. From the viewpoint of suppressing the formation of ketone bonds, TH may be preferably 1000 or less, more preferably 950 or less, and even more preferably 900 or less.
  • the residence time M may be 6 minutes or longer, preferably 8 minutes or longer, and more preferably 10 minutes or longer, from the viewpoint of reducing carboxyl groups at the ends of the molecules. Also, from the viewpoint of suppressing the formation of ketone bonds, the time may be 40 minutes or less, preferably 30 minutes or less, more preferably 25 minutes or less. Further, of the residence time M, the time y for the liquid crystalline polyester to stay in the initial low temperature region of the melting point (Mp 0 ) of the liquid crystalline polyester + 10 ° C. or less is not particularly limited, but may be 1 minute or more, preferably It may be 2 minutes or longer, or 5 minutes or shorter.
  • the maximum temperature of T x may be Mp 0 +30° C. or higher, preferably Mp 0 +40° C. or higher, more preferably Mp 0 +50° C. or higher, and still more preferably Mp from the viewpoint of reducing the carboxy group at the end of the molecule. 0 +55°C or higher. From the viewpoint of suppressing the formation of ketone bonds, the temperature may be Mp 0 +100° C. or lower, preferably Mp 0 +90° C. or lower, and more preferably Mp 0 +85° C. or lower.
  • the decarboxylation reaction Since the decarboxylation reaction is progressing in the extruder 10, carbon dioxide is generated as a pyrolysis gas. From the viewpoint of removing carbon dioxide generated by the decarboxylation reaction to the outside of the system, further promoting the decarboxylation reaction, and reducing inclusion of the generated gas as bubbles in the fiber, for example, the vent 14 of the extruder 10 It is preferable to deaerate by connecting a vacuum pump or the like to reduce the pressure in the extruder 10 .
  • the degree of vacuum may be 100 kPa or less in absolute pressure, preferably 80 kPa or less, and more preferably 60 kPa or less.
  • a known extruder such as a single-screw extruder and a multi-screw extruder (two or more screws) can be used, and a twin-screw extruder is preferable from the viewpoint of improving kneading and degassing properties.
  • melt-kneaded material containing the liquid crystalline polyester in the extruder 10 After obtaining a melt-kneaded material containing the liquid crystalline polyester in the extruder 10, it may be weighed by the gear pump 30, supplied to the spinning head 40, discharged from the nozzle 41, and melt-spun.
  • Melt spinning can be performed by a known or commonly used method, and can be obtained by discharging from a nozzle at a predetermined spinning temperature and winding with a godet roller or the like.
  • the liquid crystalline polyester fiber of the present invention can be used as a fusible fiber for producing a molding using it as a matrix.
  • a fiber structure at least partially containing liquid crystalline polyester fibers can be used as an intermediate material for producing a molded product.
  • the fiber structure containing the liquid crystalline polyester fiber of the present invention can be used in any fiber form such as staple fiber, shortcut fiber, filament yarn, spun yarn, string-like material, rope, etc., and liquid crystalline polyester fiber can be used. It can also be used as various cloths such as nonwoven fabrics, woven fabrics, and knitted fabrics. Such fibers and cloths can be produced using liquid crystalline polyester fibers by known methods.
  • the fiber structure of the present invention may be a combination of liquid crystalline polyester fibers and other fibers as long as the effects of the present invention are not impaired.
  • a composite yarn using a liquid crystal polyester fiber and another fiber for example, a mixed fiber yarn obtained by mixing a liquid crystal polyester fiber and another fiber, etc.
  • composite fabrics using liquid crystal polyester fibers and other fibers for example, mixed fabrics in which liquid crystal polyester fibers are mixed with other fibers, fabrics made from liquid crystal polyester fibers and fabrics made from other fibers
  • Laminates with other types, etc. can be used.
  • the fiber structure is used for manufacturing a reinforced fiber molding (fiber reinforced composite material)
  • the fiber structure may be a composite yarn or composite cloth containing reinforcing fibers as other fibers.
  • the type of reinforcing fiber is not particularly limited as long as it has a melting point higher than that of the liquid crystal polyester fiber of the present invention. At least one selected from the group consisting of benzobisimidazole fibers, polyparaphenylenebenzobisthiazole fibers, ceramic fibers, and metal fibers. These reinforcing fibers may be used singly or in combination of two or more.
  • the molded body may be obtained by molding a fiber structure.
  • the molded body can be obtained by heating and molding the fiber structure above the melting point of the liquid crystal polyester fiber.
  • the molding method is not particularly limited as long as the liquid crystalline polyester fibers are melted and integrated, and known molding methods for molding can be used. Since the liquid crystalline polyester fiber of the present invention has excellent hue and can suppress the generation of air bubbles during heat fusion, a molded article having excellent appearance can be obtained.
  • the obtained molded product has excellent vibration damping properties, and can be effectively used for applications that generate vibration, such as duct tubes and automobile bumpers. can be done.
  • total fineness, single fiber fineness Based on JIS L 1013: 2010 8.3.1 A method, the liquid crystal polyester fiber is wrapped around 1 m ⁇ 100 rounds (total 100 m) using a measuring instrument "Wrap Reel by Motor Driven” manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd. The weight (g) was multiplied by 100 and measured twice per standard, and the average value was taken as the total fineness (dtex) of the obtained liquid crystalline polyester fiber. The quotient obtained by dividing this value by the number of filaments was taken as the single fiber fineness (dtex).
  • the degradation product is separated by HPLC, and the peak area of the degradation product having a carboxy group is compared with a calibration curve prepared by HPLC analysis of each standard to determine the amount of carboxy terminal derived from each monomer. (meq/kg) was quantified.
  • the amount of CEG derived from monovalent carboxylic acids such as 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid can be obtained by directly quantifying 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.
  • the amount of CEG derived from divalent carboxylic acids such as terephthalic acid, isophthalic acid and 6-naphthalenedicarboxylic acid is terephthalic acid mono n-propylamide, isophthalic acid mono n-propylamide and 2,6-naphthalenedicarboxylic acid mono n- It is obtained by quantifying a substance in which one carboxyl group is amidated, such as propylamide. The total amount of all carboxy termini contained in each sample was taken as the total carboxy terminus content (total CEG content) (meq/kg) of that sample.
  • the liquid crystal polyester fiber sample was decomposed using n-propylamine, and the carboxy terminal amount derived from hydroxycarboxylic acid and the terminal carboxy group derived from hydroxycarboxylic acid were decarboxylated.
  • the total amount of terminals derived from hydroxycarboxylic acid is calculated as the number of structural units derived from hydroxycarboxylic acid with respect to all the structural units in the liquid crystalline polyester of the sample. The value obtained by dividing by the molar ratio was taken as the total single terminal amount (meq/kg) of the sample.
  • ketone binding amount The amount of ketone binding was calculated by the pyrolysis gas chromatography method described in Polymer Degradation and Stability, 76, 85-94 (2002). Specifically, using a pyrolyzer ("PY2020iD” manufactured by Frontier Lab Co., Ltd.), a liquid crystal polyester fiber sample is heated in the presence of tetramethylammonium hydroxide (TMAH), and is pyrolyzed/methylated into gas. generated. This gas was analyzed using gas chromatography (manufactured by Agilent Technologies, Inc., "GC-6890N”), and the ketone bond amount (mol%) was determined from the peak area derived from the ketone bond and the peak area derived from the ester bond. Calculated.
  • TMAH tetramethylammonium hydroxide
  • the L * value was measured using a spectrophotometer "CM-3700A” manufactured by Konica Minolta Co., Ltd., specular reflection processing: SCE, measurement diameter: LAV (25.4 mm), UV conditions: 100% Full, field of view: 2 degrees, Main light source: Measured under the condition of C light source.
  • CM-3700A manufactured by Konica Minolta Co., Ltd.
  • specular reflection processing SCE
  • measurement diameter LAV (25.4 mm)
  • UV conditions 100% Full
  • field of view 2 degrees
  • Main light source Measured under the condition of C light source.
  • GC gas chromatograph
  • a second polyimide film (same as above) was placed on the metal plate. This was sandwiched from above and below with a flat plate heating press apparatus under a pressure of 0.1 MPa or less, and contact-heated for 5 minutes at +20° C., the melting point of the liquid crystalline polyester fiber. Then, after applying a pressure of 2 MPa for 1 minute, the plate was opened to the atmosphere and cooled to 100° C. or less to obtain a liquid crystal polyester fiber-derived resin plate as a sample for appearance evaluation. The front and back of a square area of 6 cm on a side in the center of this sample for appearance evaluation was observed with a magnifying glass, and the number of air bubbles with a major axis of 1 mm or more was counted.
  • Example 1 Liquid crystal polyester ( ⁇ ) (Mp 0 : 281 ° C.) chip (granular molded body )It was used. The chips are put into a ⁇ 15mm twin-screw extruder (manufactured by Technobell Co., Ltd., "KZW15TW-45MG-NH (-700)”), melt-kneaded at a maximum temperature of 365 ° C., and weighed with a gear pump while being melt-kneaded at the spinning head. supplied things.
  • the residence time and temperature profile from the twin-screw extruder to the spinning head were set as shown in Table 5, and TH was adjusted to 553.
  • a decompression pump (dry pump manufactured by Orion Machinery Co., Ltd., "KRF40A-V-01B") is connected through a metal pipe from the vent part in the middle of the twin-screw extruder, and the resin non-filled space in the twin-screw extruder is connected.
  • the spinning head was equipped with a spinneret with a hole diameter of 0.1 mm ⁇ , a land length of 0.14 mm, and 40 holes.
  • a liquid crystalline polyester fiber (spun raw yarn) was obtained by winding on a bobbin in minutes.
  • Example 1 A method for calculating TH will be described using the manufacturing conditions of Example 1 as an example.
  • Table 5 shows the values of the heating temperature T x per minute at the residence time M, T x ⁇ (Mp 0 +10) in formula (1), and TH in Example 1.
  • Mp 0 is 281° C.
  • T x ⁇ (Mp 0 +10) is satisfied when T x is 260° C. and x is 1 to 2.
  • Time y is 2
  • T x ⁇ (Mp 0 +10) shows a positive value when x is y+1 (that is, 3) or more.
  • TH 553 can be calculated by adding all numerical values of T x ⁇ (Mp 0 +10) when x is y+1 to M (that is, 3 to 14). It was calculated in the same manner in the following examples and comparative examples.
  • Example 2 After setting the maximum temperature in the twin-screw extruder to 340 ° C., the temperature profile was changed to obtain a liquid crystal polyester fiber (spun yarn) in the same manner as in Example 1 except that TH was adjusted to 403. rice field. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 3 After setting the residence time to 11 minutes and the maximum temperature in the twin-screw extruder to 340 ° C., the TH was adjusted to 335 by changing the temperature profile, and the hole diameter was 0.1 mm ⁇ , the land length was 0.14 mm, A liquid crystalline polyester fiber (spun Raw thread) was obtained. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 4 A liquid crystal polyester fiber ( Spinning raw yarn) was obtained.
  • Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 5 After setting the residence time to 11 minutes and the maximum temperature in the twin-screw extruder to 360 ° C., the TH was adjusted to 435 by changing the temperature profile, and the hole diameter was 0.1 mm ⁇ , the land length was 0.14 mm, A liquid crystalline polyester fiber (raw yarn) was obtained in the same manner as in Example 1, except that a spinneret with 100 holes was used and the melt-kneaded material was discharged at a discharge rate of 56.0 g/min. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 6 After setting the residence time to 27 minutes and the maximum temperature in the twin-screw extruder to 340° C., TH was adjusted to 836 by changing the temperature profile, and the hole diameter was 0.125 mm ⁇ , the land length was 0.175 mm, Using a spinneret with 20 holes, the melt-kneaded material is discharged at a discharge rate of 11.0 g/min, and 5 of the 20 discharged filamentous materials are divided and wound at a winding speed of 1000 m/min. A liquid crystalline polyester fiber (spun raw yarn) was obtained in the same manner as in Example 1 except that the fiber was removed. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 7 A liquid crystal polyester fiber ( Spinning raw yarn) was obtained. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • Example 8 Liquid crystal polyester ( ⁇ ) chips are put into a ⁇ 30mm single-screw extruder (manufactured by Osaka Seiki Co., Ltd., "3VSE-30-32N type"), melt-kneaded at a maximum temperature of 340 ° C., and weighed with a gear pump while spinning heads. The melt-kneaded material was supplied to. Here, the residence time and temperature profile from the single screw extruder to the spinning head were set as shown in Table 6, and TH was adjusted to 452. The spinning head was equipped with a spinneret with a hole diameter of 0.1 mm ⁇ , a land length of 0.14 mm, and 100 holes. A liquid crystalline polyester fiber (spun raw yarn) was obtained in the same manner as in Example 1 except that the fiber was wound at a minute. Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • a certain liquid crystalline polyester ( ⁇ ) Mp 0 : 348 ° C.
  • TH A liquid crystalline polyester fiber (raw yarn) was obtained in the same manner as in Example 1, except that the was adjusted to 308.
  • Table 7 shows the analysis results of the obtained liquid crystalline polyester fiber.
  • the heat history of the liquid crystalline polyester was adjusted by the heating temperature and residence time in relation to its melting point, so that the total CEG amount could be reduced and the ketone bond amount can be suppressed. Therefore, the liquid crystalline polyester fibers of Examples 1 to 10 can suppress the amount of gas generated, and the resin plates produced using them can suppress the generation of air bubbles. In addition, the obtained liquid crystalline polyester fiber has an excellent hue and a small surface roughness, so that it can be suitably used for producing a molded article having excellent appearance and physical properties.
  • Comparative Examples 1 to 3 and 5 since the heat history of the liquid crystalline polyester is small, the amount of ketone bonds can be suppressed, but the total amount of CEG cannot be sufficiently reduced. Therefore, the liquid crystalline polyester fibers of Comparative Examples 1 to 3 and 5 generate more CO 2 gas than those of Examples 1 to 10, and the resin plates produced using them also have air bubbles compared to those of these Examples. and many occur.
  • Comparative Examples 4 and 6 the total amount of CEG can be reduced because the liquid crystalline polyester has a large heat history, but a large amount of ketone bonds is generated. Therefore, the liquid crystalline polyester fibers of Comparative Examples 4 and 6 have lower L * values and are inferior in hue as compared with Examples 1-10. Further, the liquid crystalline polyester fibers of Comparative Examples 4 and 6 have a larger surface roughness Ra than those of Examples 1-10.
  • the liquid crystalline polyester fiber of the present invention can suppress the generation of gas during heating and has an excellent hue, so it can be used as a fusible fiber for producing a molded article (for example, a fiber reinforced composite material). .

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JPWO2023058563A1 (https=) 2023-04-13
US20240417511A1 (en) 2024-12-19
KR20240056782A (ko) 2024-04-30

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