JP2009235633A - Production method of liquid crystal polyester fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal polyester fiber improved in higher-order process passability and product quality by decreasing faults caused by fusion in a solid phase polymerization process to improve uniformity in the fiber-length direction and then reducing fiber surface adherence of a fusion preventive agent. <P>SOLUTION: The production method of liquid crystal polyester fiber comprises adhering a fusion preventive agent on the surface of the liquid crystal polyester fiber, performing solid-phase polymerization, and removing the fusion preventive agent while travelling the solid phase-polymerized polyester fiber, so that the adhesion amount of the fusion preventive agent on the fiber is made 4.0 wt.% or less based on the fiber weight. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a liquid crystal polyester fiber which is excellent in uniformity in the fiber longitudinal direction, has few fiber surface deposits such as an anti-fusing agent, and is excellent in high-order process passability.

  Liquid crystalline polyester is a polymer composed of rigid molecular chains. In melt spinning, the molecular chains are highly oriented in the fiber axis direction, and further subjected to heat treatment (solid phase polymerization). It is known that the highest strength and elastic modulus can be obtained. In addition, it is also known that liquid crystal polyester has an increased molecular weight due to solid-phase polymerization and an increased melting point, thereby improving heat resistance and dimensional stability (see Non-Patent Document 1). Thus, liquid crystal polyester fibers exhibit high strength, high elastic modulus, excellent heat resistance, and thermal dimensional stability by solid phase polymerization.

  Solid-phase polymerization of liquid crystalline polyester fiber is industrially adopted as a method of treating the fiber as a package from the viewpoint of simplifying equipment and improving productivity, but the solid-phase polymerization reaction proceeds. There is a problem that fusion between single yarns is likely to occur in a temperature range, and the fusion part is peeled off during unwinding from the package shape. Defects deteriorate the uniformity in the longitudinal direction of the fiber, such as a decrease in strength, and also cause problems such as fiber fibrillation starting from the defects.

  In recent years, especially for filters made of monofilament and screen printing saddles, there has been a growing demand for higher weaving density (higher mesh), lowering the thickness, and improving the opening ratio of the opening (opening) to improve performance. In order to achieve this, there is a strong demand for fineness and high strength of the single fiber fineness, and at the same time, there is a demand for reducing defects in the opening for high performance. The defects of the openings are caused by friction in the fiber manufacturing process or the high-order processing process, thus reducing defects caused by fusion in solid-phase polymerization, and uniform strength and fineness in the longitudinal direction of the fiber. There is a need to improve.

  In addition, deterioration in process passability in fiber high-order processing such as weaving is caused by fluctuations in tension due to fibril catching and fibril deposition on the guide, reducing defects caused by fusion in solid phase polymerization, There is a need to improve the uniformity of strength and fineness in the direction.

  As a technique for reducing fusion in solid phase polymerization, a method of treating with talc or silica and then heat-treating (solid phase polymerization) (see Patent Document 1), a surfactant containing a fluorine atom having a decomposition temperature of 200 ° C. or higher A method of heat-treating (solid-phase polymerization) the fibers after adhering the fibers (see Patent Document 2) is disclosed. In these methods, the effect of reducing fusion is recognized, and as the amount of adhesion increases, the fusion decreases. However, since anti-fusing agents such as talc, silica, and fluorine compounds remain on the fiber surface as a deposit, weaving In addition to the adhesion of the anti-fusing agent to the guide and the like in the high-order processing step of the fiber and the like, the passability of the process deteriorates. When the adhesion amount is reduced to avoid this, there is a problem that the effect of improving the fusion is reduced, and defects due to the fusion are increased to deteriorate the uniformity in the fiber longitudinal direction.

In addition, Patent Document 2 describes that “heat-treated fibers are washed and dried after cooling if desired”, but there is no description of a specific method of washing and its effect.
Edited by Technical Information Association, “Modification of liquid crystal polymer and latest applied technology” (2006) (pages 235-256) JP 58-91817 A (page 5) JP 63-99328 A (first page)

  The object of the present invention is to reduce defects caused by fusion in solid-phase polymerization, increase the uniformity in the longitudinal direction of the fiber, and reduce the adhesion of fibers on the fiber surface such as an anti-fusing agent, and is excellent in high-order process passability. It is providing the manufacturing method of a polyester fiber.

  The present inventors have found that it is difficult to achieve both fusion suppression in solid phase polymerization and improvement in high-order process passability with the same amount of fiber surface deposits. It was found that both can be satisfied by removal.

  That is, the present invention removes the anti-fusing agent while the solid-phase polymerized liquid crystal polyester fiber is running after the anti-fusing agent is attached to the liquid crystal polyester fiber, and the anti-fusing agent to the fiber. This is a method for producing a liquid crystal polyester fiber, characterized in that the amount of adhering is 4.0% by weight or less with respect to the fiber weight.

  The present invention has few defects on the fiber surface, excellent uniformity in the longitudinal direction of the fiber, and solid-state polymerized liquid crystal polyester fibers with good high-order process passability can be obtained efficiently. When used, a fabric with improved quality can be obtained by improving the weaving properties and reducing the defects of the fabric opening.

  Hereinafter, the manufacturing method of the liquid crystalline polyester fiber of this invention is demonstrated in detail.

  The liquid crystal polyester used in the present invention is a polyester capable of forming an anisotropic melt phase (liquid crystallinity) upon melting. This characteristic can be confirmed, for example, by placing a sample made of liquid crystal polyester on a hot stage, heating and heating in a nitrogen atmosphere, and observing the transmitted light of the sample under polarized light.

  Examples of the liquid crystal polyester used in the present invention include a. A polymer of aromatic oxycarboxylic acid, b. Polymer of aromatic dicarboxylic acid and aromatic diol, aliphatic diol, c. Examples include a copolymer of a and b, and a wholly aromatic polyester that does not use an aliphatic diol is preferable for high strength, high elastic modulus, and high heat resistance. Here, examples of the aromatic oxycarboxylic acid include hydroxybenzoic acid, hydroxynaphthoic acid and the like, and alkyl, alkoxy and halogen substituted products of the above aromatic oxycarboxylic acid. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, and the like, or alkyls, alkoxys of the above aromatic dicarboxylic acids, Examples include halogen substitution products. Furthermore, examples of the aromatic diol include hydroquinone, resorcin, dioxydiphenyl, naphthalene diol, and the like, and alkyl, alkoxy, and halogen substituted products of the above aromatic diol. Examples of the aliphatic diol include ethylene glycol, propylene glycol, Examples include butanediol and neopentyl glycol.

  Preferable examples of the liquid crystalline polyester used in the present invention include a copolymer of a p-hydroxybenzoic acid component, a 4,4′-dihydroxybiphenyl component, a hydroquinone component, a terephthalic acid component and / or an isophthalic acid component, p- A copolymer of a hydroxybenzoic acid component and a 6-hydroxy 2-naphthoic acid component, a copolymer of a p-hydroxybenzoic acid component, a 6-hydroxy 2-naphthoic acid component, a hydroquinone component, and a terephthalic acid component , Etc.

  In the present invention, a liquid crystal polyester composed of the following structural units (I), (II), (III), (IV) and (V) is particularly preferable. In the present invention, the structural unit refers to a unit that can constitute a repeating structure in the main chain of the polymer.

  This combination allows the molecular chains to have appropriate crystallinity and non-linearity, i.e. a melt-spinnable melting point. Therefore, the fiber has good spinning performance at the spinning temperature set between the melting point of the polymer and the thermal decomposition temperature, and a uniform fiber can be obtained in the longitudinal direction. Can be increased.

  Furthermore, it is important to combine components composed of diols that are not bulky and have high linearity such as structural units (II) and (III). By combining these components, the molecular chains in the fibers are ordered and disordered. In addition to having a small structure, the crystallinity is not excessively increased and the interaction in the direction perpendicular to the fiber axis can be maintained. Thereby, in addition to obtaining high strength and elastic modulus, excellent wear resistance is also obtained.

  Further, the structural unit (I) is preferably 40 to 85 mol%, more preferably 65 to 80 mol%, still more preferably 68 to 85 mol% with respect to the total of the structural units (I), (II) and (III). 75 mol%. By setting it as such a range, crystallinity can be made into an appropriate range, high intensity | strength and an elasticity modulus are obtained, and melting | fusing point also becomes the range which can be melt-spun.

  The structural unit (II) is preferably 60 to 90 mol%, more preferably 60 to 80 mol%, still more preferably 65 to 75 mol%, based on the total of the structural units (II) and (III). By setting it as such a range, since crystallinity does not become high excessively and the interaction of a fiber axis perpendicular | vertical direction can be maintained, it is excellent in abrasion resistance.

  The structural unit (IV) is preferably 40 to 95 mol%, more preferably 50 to 90 mol%, still more preferably 60 to 85 mol%, based on the total of the structural units (IV) and (V). By setting such a range, the melting point of the polymer becomes an appropriate range, and has a good spinning property at a spinning temperature set between the melting point of the polymer and the thermal decomposition temperature. Uniform fibers can be obtained.

The preferred range of each structural unit of the liquid crystalline polyester used in the present invention is as follows. A particularly suitable liquid crystal polyester fiber can be obtained by adjusting the composition so as to satisfy the above-mentioned conditions within this range.
Structural unit (I) 45-65 mol%
Structural unit (II) 12-18 mol%
Structural unit (III) 3 to 10 mol%
Structural unit (IV) 5-20 mol%
Structural unit (V) 2-15 mol%
In addition to the above structural units, the liquid crystalline polyester used in the present invention includes aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid and 2,2′-diphenyldicarboxylic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid. Aliphatic dicarboxylic acids such as hexahydroterephthalic acid (1,4-cyclohexanedicarboxylic acid), chlorohydroquinone, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfide, 4 An aromatic diol such as 4,4'-dihydroxybenzophenone and p-aminophenol may be copolymerized within a range of about 5 mol% or less without impairing the effects of the present invention.

  Further, in the range of about 5% by weight or less which does not impair the effects of the present invention, a vinyl polymer such as polyester, polyolefin or polystyrene, polycarbonate, polyamide, polyimide, polyphenylene sulfide, polyphenylene oxide, polysulfone, aromatic polyketone, aliphatic polyketone. , Semi-aromatic polyester amide, polyether ether ketone, fluororesin and other polymers may be added. Polyphenylene sulfide, polyether ether ketone, nylon 6, nylon 66, nylon 46, nylon 6T, nylon 9T, polyethylene terephthalate, Polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycyclohexanedimethanol terephthalate, polyester 99M, etc. are suitable It is mentioned as examples. When these polymers are added, the melting point thereof is preferably within the melting point ± 30 ° C. of the liquid crystalline polyester so as not to impair the spinning property.

  Furthermore, within the range not impairing the effects of the present invention, various metal oxides, kaolin, silica and other inorganic substances, colorants, matting agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents In addition, various additives such as a fluorescent brightening agent, a terminal group blocking agent, and a compatibilizing agent may be contained in a small amount.

  The method for producing the liquid crystal polyester used in the present invention can be produced according to a known production method. For example, the following production methods are preferred.

  (1) Deacetic acid from acetoxycarboxylic acid such as p-acetoxybenzoic acid and diacetylated compounds of aromatic dihydroxy compounds such as 4,4′-diacetoxybiphenyl and diacetoxybenzene and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid A method for producing a liquid crystalline polyester by a condensation polymerization reaction.

  (2) Hydroxycarboxylic acid such as p-hydroxybenzoic acid and aromatic dihydroxy compounds such as 4,4′-dihydroxybiphenyl and hydroquinone and aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid are reacted with acetic anhydride to produce phenol. A method for producing a liquid crystalline polyester by deacetic acid polycondensation reaction after acylating a functional hydroxyl group.

  (3) Dephenolization from phenyl esters of hydroxycarboxylic acids such as p-hydroxybenzoic acid and aromatic dihydroxy compounds such as 4,4′-dihydroxybiphenyl and hydroquinone and diphenyl esters of aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid A method for producing a liquid crystalline polyester by a polycondensation reaction.

  (4) A predetermined amount of diphenyl carbonate is reacted with a hydroxycarboxylic acid such as p-hydroxybenzoic acid and an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid to form a diphenyl ester, and then 4,4′-dihydroxybiphenyl. A method for producing a liquid crystalline polyester by dephenol polycondensation reaction by adding an aromatic dihydroxy compound such as hydroquinone.

  Among them, hydroxycarboxylic acids such as p-hydroxybenzoic acid, aromatic dihydroxy compounds such as 4,4′-dihydroxybiphenyl and hydroquinone, and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid are reacted with acetic anhydride to produce phenolic compounds. A method of producing a liquid crystalline polyester by deacetic acid polycondensation reaction after acylating a hydroxyl group is preferred. Furthermore, the total amount of aromatic dihydroxy compounds such as 4,4'-dihydroxybiphenyl and hydroquinone and the total amount of aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid are substantially equimolar. The amount of acetic anhydride used is preferably 1.12 equivalents or less, more preferably 1.10 equivalents or less of the total of the phenolic hydroxyl groups of p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl and hydroquinone. Preferably, the lower limit is 1.0 equivalent or more.

  When the liquid crystalline polyester used in the present invention is produced by a deacetic acid polycondensation reaction, a melt polymerization method in which the polycondensation reaction is completed by reacting under reduced pressure at a temperature at which the liquid crystalline polyester melts is preferable. For example, a predetermined amount of a hydroxycarboxylic acid such as p-hydroxybenzoic acid and an aromatic dihydroxy compound such as 4,4′-dihydroxybiphenyl and hydroquinone, an aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid, and an acetic anhydride stirring blade, Charged into a reaction vessel equipped with a distillation pipe and provided with a discharge port at the bottom, heated under stirring in a nitrogen gas atmosphere to acetylate the hydroxyl group, then raised to the melting temperature of the liquid crystalline resin, and reduced pressure A method of completing the reaction by polycondensation is mentioned. The conditions for the acetylation are usually 130 to 300 ° C., preferably 135 to 200 ° C., usually 1 to 6 hours, preferably 140 to 180 ° C. for 2 to 4 hours. The polycondensation temperature is the melting temperature of the liquid crystal polyester, for example, in the range of 250 to 350 ° C., and preferably the melting point of the liquid crystal polyester polymer + 10 ° C. or higher. The degree of pressure reduction during polycondensation is usually 13.3 to 2660 Pa, preferably 1330 Pa or less, more preferably 665 Pa or less. In addition, although acetylation and polycondensation may be performed continuously in the same reaction vessel, acetylation and polycondensation may be performed in different reaction vessels.

  The obtained polymer can be pressurized in the reaction vessel to, for example, about 0.1 ± 0.05 MPa at a temperature at which it melts and discharged in a strand form from the discharge port provided at the lower portion of the reaction vessel. The melt polymerization method is an advantageous method for producing a uniform polymer, and an excellent polymer with less gas generation can be obtained, which is preferable.

  When producing the liquid crystalline polyester used in the present invention, the polycondensation reaction can be completed by a solid phase polymerization method. For example, the liquid crystal polyester polymer or oligomer is pulverized by a pulverizer, and the melting point (Tm) -5 ° C. to the melting point (Tm) −50 ° C. (for example, 200 to 300 ° C.) of the liquid crystal polyester under a nitrogen stream or reduced pressure. A method of heating for 1 to 50 hours, polycondensing to a desired degree of polymerization, and completing the reaction can be mentioned.

  However, in spinning, if the liquid crystalline resin produced by the solid phase polymerization method is used as it is, the highly crystallized portion generated by the solid phase polymerization remains unmelted, which causes an increase in spinning pack pressure and foreign matter in the yarn. Since there is a possibility, it is preferable that the highly crystallized portion is completely melted by kneading (repletizing) once with a twin screw extruder or the like.

  The polycondensation reaction of the liquid crystal polyester proceeds even without catalyst, but metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, and magnesium metal can also be used.

  The melting point of the liquid crystalline polyester polymer used in the present invention is preferably 200 to 380 ° C., more preferably 250 to 350 ° C., and further preferably 290 to 340 ° C. in order to widen the temperature range capable of melt spinning. In addition, melting | fusing point (endothermic peak) of a liquid crystal polyester polymer points out the value measured by the method of an Example description.

  The melt viscosity of the liquid crystalline polyester polymer used in the present invention is preferably 0.5 to 200 Pa · s, particularly preferably 1 to 100 Pa · s, and more preferably 10 to 50 Pa · s from the viewpoint of spinnability. The melt viscosity is a value measured with a Koka flow tester under the condition of melting point (Tm) + 10 ° C. and shear rate of 1,000 (1 / s).

  The polystyrene equivalent weight average molecular weight (hereinafter referred to as molecular weight) of the liquid crystalline polyester used in the present invention is preferably 30,000 or more, and more preferably 50,000 or more. By setting the molecular weight to 30,000 or more, the spinning property can be improved with an appropriate viscosity at the spinning temperature, and the higher the molecular weight, the higher the strength, elongation and elastic modulus of the resulting fiber. On the other hand, if the molecular weight is too high, the viscosity becomes high, the fluidity is deteriorated, and finally the fluid does not flow. Therefore, the molecular weight is preferably less than 255,000, more preferably less than 150,000.

  In melt spinning, a known method can be used for melt extrusion of liquid crystal polyester, but an extruder type extruder is preferably used in order to eliminate the ordered structure generated during polymerization. The extruded polymer is measured by a known measuring device such as a gear pump through a pipe, and after passing through a filter for removing foreign matter, it is led to a base. At this time, the temperature from the polymer pipe to the die (spinning temperature) is preferably not lower than the melting point of the liquid crystal polyester and not higher than 500 ° C., more preferably not lower than the melting point of the liquid crystal polyester + 10 ° C. and not higher than 400 ° C. More preferably, the melting point is 20 ° C. or higher and 370 ° C. or lower. It is also possible to independently adjust the temperature from the polymer pipe to the base. In this case, the discharge is stabilized by making the temperature of the part close to the base higher than the temperature on the upstream side.

  In melt spinning, in order to obtain fibers with fineness and low fineness fluctuation rate, stability during discharge and stability of thinning behavior should be improved. In industrial melt spinning, energy costs are reduced and production is reduced. In order to improve the performance, a large number of base holes are drilled in one base, and it is necessary to stabilize the discharge and thinning of each hole.

  In order to achieve this, it is important to reduce the diameter of the base hole and increase the land length (the length of the straight pipe portion equal to the diameter of the base hole). However, if the hole diameter is excessively small, clogging of the hole is likely to occur, so that the diameter is preferably 0.03 mm to 0.30 mm, more preferably 0.05 mm to 0.25 mm, and further preferably 0.08 mm to 0.20 mm. preferable. If the land length is excessively long, the pressure loss increases. Therefore, the L / D defined by the quotient obtained by dividing the land length by the hole diameter is preferably 0.5 or more and 3.0 or less, more preferably 0.8 or more and 2.5 or less. Preferably, it is 1.0 or more and 2.0 or less. In order to maintain uniformity, the number of holes in one die is preferably 50 holes or less, more preferably 40 holes or less, and even more preferably 20 holes or less. In addition, it is preferable that the introduction hole located immediately above the die hole is a straight hole having a diameter of 5 times or more the diameter of the die hole in terms of not increasing pressure loss. It is preferable to taper the connection part between the introduction hole and the base hole in order to suppress abnormal stagnation. However, the length of the taper part should be less than twice the land length without increasing pressure loss and stabilizing the streamline. This is preferable.

  The polymer discharged from the base hole passes through a heat retaining and cooling region and solidifies, and is then taken up by a roller (godet roller) that rotates at a constant speed. If the heat-retaining region is excessively long, the yarn forming property is deteriorated, so that it is preferably up to 200 mm from the base surface, and more preferably up to 100 mm. In the heat retaining region, the atmospheric temperature can be increased by using a heating means, and the temperature range is preferably 100 ° C. or higher and 500 ° C. or lower, and more preferably 200 ° C. or higher and 400 ° C. or lower. For the cooling, an inert gas, air, water vapor, or the like can be used. However, it is preferable to use an air flow that is jetted in parallel or in an annular shape from the viewpoint of reducing the environmental load.

  The take-up speed is preferably 50 m / min or more, more preferably 300 m / min or more, and further preferably 500 m / min or more in order to reduce productivity and single yarn fineness. As a preferred example, the liquid crystal polyester composed of the five components described above has a suitable spinnability at the spinning temperature, so that the take-up speed can be increased. The upper limit is not particularly limited, but is about 2000 m / min from the viewpoint of spinnability.

  The spinning draft defined by the quotient obtained by dividing the take-off speed by the discharge linear speed is preferably 1 or more and 500 or less, more preferably 5 or more and 200 or less, and even more preferably 12 or more and 100 or less. In addition, since the liquid crystalline polyester which consists of 5 components mentioned as a preferable example has a suitable spinnability, a draft can be made high and it is advantageous to refinement | definement.

  In melt spinning, it is preferable to add an oil agent between the cooling and solidification of the polymer and the winding to improve the handleability of the fiber. As the oil agent, known oil agents can be used, but it is more preferable to use an oil agent mainly composed of polysiloxane-based silicone oil that can withstand solid-phase polymerization at high temperatures.

  Winding can be carried out using a known winder to form a package such as pirn, cheese, corn, etc. However, it is not necessary to make the wrapping so that the roller does not come into contact with the surface of the package during winding. It is preferable in that it is not fibrillated.

  Next, the fiber obtained by melt spinning is subjected to solid phase polymerization. In the present invention, an anti-fusing agent is attached to the fiber surface before solid phase polymerization. The adhesion of the anti-fusing agent may be carried out between melt spinning and winding, but in order to increase the adhesion efficiency, it is performed at the time of rewinding, or a small amount is adhered by melt spinning and further added at the time of rewinding. It is preferable to do.

  The anti-fusing agent referred to in the present invention is an agent that suppresses fusion between fibers when the agent is attached to a liquid crystal polyester fiber and solid-phase polymerized, and publicly known ones can be used. High heat resistance is preferable because it does not volatilize at high temperature heat treatment in, for example, inorganic salts such as barium sulfate and barium titanate, inorganic substances such as talc, silica, smectite, synthetic mica, fluorine compounds, aromatic polyamides, polyimides, poly High heat resistant organic substances such as ether ketone, polysiloxane compounds such as dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane and modified products thereof, and mixtures thereof are preferred. Of these, polysiloxane compounds are particularly preferred because they exhibit an effect on slipperiness in addition to the effect of preventing fusion in solid phase polymerization. Polysiloxane compounds are well known as oil agents exhibiting slipperiness, but it is a new fact that they are highly effective in preventing fusion in solid phase polymerization.

  These components may be applied directly to solid or liquid substances, but in order to apply uniformly while optimizing the amount of adhesion, application with a solution or emulsion is preferred, preventing flammability when combustible materials are used, and environmental impact From the viewpoint of reducing water, an aqueous solution and water emulsion using water are particularly preferred. Therefore, it is desirable that the anti-fusing agent be water-soluble or easily form a water emulsion, and most preferably a mixture composed mainly of a water emulsion of dimethylpolysiloxane and added with a water-soluble salt or water-swellable smectite. A known method such as an oiling guide can be employed for applying the solution or emulsion, but a method of attaching using a kiss roll (oiling roll) made of metal or ceramic is preferable in order to improve the uniformity in the longitudinal direction.

  The amount of adhesion of the anti-fusing agent to the fiber is preferably large in order to suppress the fusion, preferably 0.5% by weight or more, and more preferably 1.0% by weight or more. On the other hand, if the amount is too large, the fiber tends to deteriorate sticky handling, and the amount of residue increases after removal of deposits and deteriorates processability, so 10.0% by weight or less is preferable, and 8.0% by weight or less is more preferable. It is preferably 6.0% by weight or less. In addition, the adhesion amount of the anti-fusing agent to the fiber indicates a value obtained by the method described in the examples. In this case, when measuring the adhesion amount of the anti-fusing agent, the adhesion amount of the oil agent or the like applied in the melt spinning is also added, but depending on the type of the oil agent applied by the melt spinning, an anti-fusing effect is exhibited. When the adhesion amount is large, problems similar to those of the anti-fusing agent such as deterioration in handling occur. Therefore, in the present invention, the adhesion amount of the oil agent or the like applied in melt spinning is also calculated as a total amount with the anti-fusion agent.

  Solid-phase polymerization can be processed in the form of a package, cake, tow (for example, on a metal net), or as a continuous thread between rollers, but the equipment can be simplified and produced. It is preferable to carry out in the form of a package from the viewpoint of improving the properties.

  When solid-phase polymerization is performed in a package form, a technique for preventing fusion that becomes noticeable when the single fiber fineness is reduced is also important. In order to prevent fusion, the winding density of the fiber package at the time of solid-phase polymerization is important, and the winding density is formed on the bobbin as a fiber package having a winding density of 0.01 g / cc or more and less than 0.30 g / cc, This is preferably solid phase polymerized. Here, the winding density is a value calculated by Wf / Vf from the occupied volume Vf (cc) of the package and the weight Wf (g) of the fiber obtained from the outside dimensions of the package and the dimensions of the bobbin that is the core material. The occupied volume Vf is a value obtained by actually measuring the outer dimension of the package or by taking a photograph and measuring the outer dimension on the photograph and assuming that the package is rotationally symmetric. Wf is the fineness And a value calculated from the winding length, or a value measured by a weight difference before and after winding. The lower the winding density, the weaker the adhesion between the fibers in the package and the suppression of fusion, so 0.15 g / cc or less is preferable, and if the winding density is too small, the package collapses and is 0.03 g / cc or more. It is preferable. Therefore, a preferable range is 0.03 g / cc or more and 0.15 g / cc or less. Further, it is preferable to use fibers having a total fineness of 1 dtex or more that can be handled and a total fineness of 500 dtex or less that has a large adverse effect due to fusion.

  When such a low winding density package is formed by winding in melt spinning, it is desirable to improve facility productivity and production efficiency. On the other hand, a package wound by melt spinning is formed by rewinding. Is preferable because the winding tension can be reduced and the winding density can be further reduced. In the rewinding, the winding density can be reduced as the winding tension is reduced. Therefore, the winding tension is preferably 0.15 cN / dtex or less, more preferably 0.10 cN / dtex or less, and further preferably 0.05 cN / dtex or less. In order to reduce the winding density, the surface of the fiber package is wound in a non-contact state or wound by melt spinning without using a contact roller or the like normally used to adjust the package shape and stabilize the winding tension. It is also effective to wind the package directly with a winder controlled in speed without using a speed control roller. In these cases, in order to adjust the package shape, a method in which the distance (free length) from the contact point between the traverse guide and the fiber to the fiber package is within 10 mm is preferably used. Furthermore, it is also effective to reduce the winding density by setting the winding speed to 500 m / min or less, particularly 300 m / min or less. On the other hand, a higher rewinding speed is advantageous for productivity, and it is preferably 50 m / min or more, particularly preferably 100 m / min or more.

  In addition, in order to form a stable package even in low tension winding, and in order to avoid fusion of the end face and form a stable package, the winding form should be tapered end winding with both ends tapered. preferable. At this time, the taper angle is preferably 60 ° or less, and more preferably 45 ° or less. When the taper angle is small, the fiber package cannot be enlarged, and when long fibers are required, it is preferably 1 ° or more, and more preferably 5 ° or more. The taper angle referred to in the present invention is defined by the following equation. Furthermore, in winding, the traverse width is periodically swung with respect to time, whereby a package having excellent handling and unwinding properties can be obtained.

  Furthermore, the number of winds is also important for package formation. The number of winds referred to here is the number of revolutions that the spindle rotates while the traverse makes a half-reciprocation. It is defined as the product of the time (minutes) of the traverse half-reciprocation and the spindle number of revolutions (rpm). Indicates that the twill angle is small. The smaller the number of winds, the smaller the contact area between the fibers, which is advantageous for avoiding fusion. However, the higher the number of winds under the conditions such as low tension and no contact roll, which are preferable winding conditions in the present invention. Twill fall off at the end face and the swelling of the package can be reduced, and the package shape is improved. From these points, the wind number is preferably 2.0 or more and 20.0 or less, and more preferably 5.0 or more and 15.0 or less.

  The bobbin used to form the fiber package may be of any cylindrical shape, and when wound as a fiber package, it is attached to a winder and rotated to wind the fiber and form a package. To do. In the solid-phase polymerization, the fiber package can be processed integrally with the bobbin, but the bobbin alone can be extracted from the fiber package for processing. When the treatment is carried out while being wound around the bobbin, the bobbin needs to withstand the solid phase polymerization temperature, and is preferably made of a metal such as aluminum, brass, iron or stainless steel. Further, in this case, it is preferable that the bobbin has a large number of holes because the polymerization reaction by-products can be removed quickly and solid phase polymerization can be performed efficiently. Further, when the bobbin is extracted from the fiber package and processed, it is preferable to attach an outer skin to the bobbin outer layer. In any case, it is preferable that a cushion material is wound around the outer layer of the bobbin, and the liquid crystalline polyester melt-spun fiber is wound thereon. The cushion material is preferably felt made of organic fiber or metal fiber, and the thickness is preferably 0.1 mm or more and 20 mm or less. The aforementioned outer skin can be substituted with the cushion material.

  The fiber weight of the fiber package is preferably 0.01 kg or more and 10 kg or less in consideration of productivity. The yarn length is preferably in the range of 10,000 m to 2 million m.

  Solid-phase polymerization can be carried out in an inert gas atmosphere such as nitrogen, an oxygen-containing active gas atmosphere such as air, or under reduced pressure, but it can simplify equipment and prevent oxidation of fibers or deposits. Therefore, it is preferable to carry out in a nitrogen atmosphere. At this time, the atmosphere of the solid phase polymerization is preferably a low-humidity gas having a dew point of −40 ° C. or less.

  As for the solid phase polymerization temperature, when the endothermic peak (melting point) of the liquid crystal polyester fiber to be subjected to solid phase polymerization is defined as Tm1 (° C.), it is preferable that the maximum reached temperature is Tm 1-60 ° C. or higher. By setting the temperature close to the melting point, solid phase polymerization can proceed rapidly and the strength of the fiber can be improved. In addition, Tm1 said here points out the value calculated | required by the measuring method of an Example description. It is preferable that the maximum temperature is less than Tm1 (° C.) in order to prevent fusion. Moreover, since the melting point of the liquid crystal polyester fiber increases with the progress of the solid phase polymerization, the solid phase polymerization temperature can be increased to the melting point of the liquid crystal polyester fiber subjected to the solid phase polymerization + about 100 ° C. Increasing the solid-phase polymerization temperature stepwise or continuously with respect to time is more preferable because it can prevent fusion and increase the time efficiency of solid-phase polymerization. However, also in this case, it is preferable that the maximum temperature achieved in the solid phase polymerization is Tm1-60 (° C.) or higher and less than Tm1 (° C.) of the fiber after heat treatment from the viewpoint of increasing the solid phase polymerization rate and preventing fusion. .

  The solid phase polymerization time is preferably 5 hours or more at the maximum temperature, and more preferably 10 hours or more in order to sufficiently increase the strength, elastic modulus and melting point of the fiber. The upper limit is not particularly limited, but the effect of increasing strength, elastic modulus, and melting point is saturated with the passage of time, so about 100 hours is sufficient, and in order to increase productivity, a short time is preferable, and about 50 hours is sufficient.

  The package after the solid phase polymerization is preferably rewound again to increase the winding density in order to increase the transport efficiency. At this time, when unwinding the fiber from the solid-phase polymerization package, the solid-phase polymerization package is rotated to prevent collapse of the solid-phase polymerization package due to unraveling and to suppress fibrillation when peeling a slight fusion. It is preferable that the yarn is unwound by so-called pre-winding, in which the yarn is unwound in the direction perpendicular to the rotation axis (fiber wrapping direction), and the solid-phase polymerization package is not freely rotated but is rotated by positive drive. This is preferable in that the yarn separation tension from the fiber can be reduced and fibrillation can be further suppressed.

  Next, in the present invention, the anti-fusing agent is removed from the fiber subjected to solid phase polymerization. The greater the amount of adhesion of the anti-fusing agent, the higher the effect on the suppression of fusion in solid-phase polymerization, but if there is too much anti-fusing agent in the processes after solid-phase polymerization or weaving process, It is preferable to reduce the adhesion amount of the anti-fusing agent to the minimum necessary because it causes deterioration of process passability due to deposition and generation of defects due to inclusion of the deposit into the product. For this reason, it is possible to achieve both suppression of fusion, improvement of uniformity in the longitudinal direction and improvement of process passability by removing the anti-fusing agent adhered before solid-phase polymerization after solid-phase polymerization.

  In the present invention, the anti-fusing agent is removed while running the fiber subjected to solid phase polymerization. By removing while running, a large amount of fibers can be processed continuously and uniformly, so that the removal efficiency in the longitudinal direction of the fibers can be made uniform, and the equipment can be simplified such that it can be processed continuously with the above-described unwinding step.

  The term “removal” as used in the present invention means that the adhesion amount of the anti-fusing agent adhering to the fiber is decreased and the removed anti-fusing agent is not deposited again on the fiber surface. By suppressing the amount of adhesion of the anti-fusing agent in the higher order / product and not depositing it, it is possible to suppress the problem that the anti-fusing agent adheres to the fiber again non-uniformly and becomes a disadvantage of increasing the amount of adhesion unevenly.

  When the solid phase polymerization is performed with a package, the fiber to be removed may be used as it is after the solid phase polymerization, or may be used after rewinding the package after the solid phase polymerization. When the package after the solid-phase polymerization is used as it is, the rewinding step is unnecessary, which is preferable because the equipment can be simplified. In the case of rewinding and using, the removal degree can be easily adjusted by adjusting the process speed of the unwinding and removing process, and the equipment productivity is excellent.

  As the removal method, cloth, paper, porous material, etc. can be applied to the running fiber and wiped off. However, the anti-fusing agent dissolves or disperses in that the removal efficiency can be improved without applying a mechanical load to the fiber. It is preferred to bring the fibers into contact with the liquid that can be produced. The method of contacting the liquid may be a method of continuously spraying the liquid on the fiber or contacting the liquid using a kiss roll, but the method of running the fiber in a bath filled with liquid reduces the amount of liquid used. This is preferable in that the liquid can be prevented from being scattered and the contact time with the liquid can be increased. At this time, the fiber may be passed through the bath only once. However, using a free roller, a turn roller, a Nelson roller, etc., allowing the fiber to pass through the bath a plurality of times can reduce the bath size. This is preferable in that the amount of liquid can be reduced and the contact time can be increased. Addition of surfactant to liquid, bubble or ultrasonic vibration of liquid, application of liquid flow, application of vibration to fiber immersed in liquid, contact of fiber with other objects in liquid, etc. Is particularly preferable for increasing the dissolution or dispersion rate of the anti-fusing agent in the liquid. Before removing the anti-fusing agent while running, a method such as applying a liquid in the state of the package, that is, applying a liquid to the package or immersing the package in a bath containing the liquid is a method of the anti-fusing agent. The method of improving the removal efficiency is preferable, and the method of ultrasonic cleaning by immersing the package in a bath containing a liquid is more preferable in terms of further improving the removal efficiency of the anti-fusing agent.

  As the liquid used for removal, various organic solvents can be used in addition to water. Examples include chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,2-dichloroethylene, 1,1,2,2-tetrachloroethane, Trichloroethylene, carbon disulfide, acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, ethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ortho-dichlorobenzene , Xylene (ortho), xylene (meth), xylene (para), cresol (ortho), cresol (meth), cresol (para), chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate , Ethyl acetate, butyl acetate, propyl acetate, pentyl acetate, methyl acetate, cyclohexanol, cyclohexanone, 1,4-dioxane, dichloromethane, N, N-dimethylformamide, styrene, tetrachloroethylene, tetrahydrofuran, 1,1,1 -Trichloroethane, toluene, normal hexane, 1-butanol, 2-butanol, propanol, ethanol, methanol, methyl isobutyl ketone, methyl ethyl ketone, methyl cyclohexanol, methyl cyclohexanone, methyl butyl ketone, industrial gasoline 1-5, coal tar naphtha (Solvent naphtha) Nos. 1 to 3, petroleum ether, petroleum naphtha (light and heavy), petroleum benzine (reagent), turpentine oil, mineral spirits and mixtures thereof. Eliminate the possibility of, it is preferable that the water in order to reduce the environmental impact.

  The surfactant can be appropriately used depending on the type of anti-fusing agent. For example, as an anionic surfactant, a fatty acid salt, an alpha sulfo fatty acid ester salt, an alkyl benzene sulfonate, a linear alkyl benzene sulfonate, an alkyl sulfate. , Alkyl ether sulfate ester salt, alkyl sulfate triethanolamine, alkyl phosphate ester, fatty acid diethanolamide as nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl Phenyl ethers, sorbitan alkyl esters, higher amine halogenates, alkyltrimethylammonium salts, dialkyldimethylammonium chlorides, alkylpyridines as cationic surfactants Niumukurorido, alkyl carboxy betaine and a mixture thereof can be preferably used as a zwitterionic surfactant.

  Since the higher the temperature of the liquid, the higher the removal efficiency, the boiling point of the liquid is preferably −80 ° C. or higher, the liquid boiling point −60 ° C. or higher is more preferable, and the liquid boiling point −40 ° C. or higher is more preferable. However, if the temperature is too high, the evaporation of the liquid becomes remarkable, so the boiling point of the liquid is preferably −10 ° C. or lower, more preferably the boiling point of −20 ° C. or lower.

  The longer the contact time with the liquid, the higher the removal efficiency, so 0.01 seconds or more is preferable, 0.1 seconds or more is more preferable, and 0.5 seconds or more is even more preferable. Although the upper limit is not determined, it is about 30 seconds or less in order to reduce the equipment.

  The contact length with the liquid should depend on the speed, but should be long enough to ensure the above processing time, preferably 30 cm or more, more preferably 50 cm or more, and even more preferably 1 m or more. Although the upper limit is not determined, it is about 20 m or less in order to reduce the equipment.

  The fiber traveling speed is preferably higher in order to increase the throughput per unit time, preferably 10 m / min or more, more preferably 50 m / min or more, and even more preferably 100 m / min or more. However, when the speed is excessively high, the liquid is scattered by an accompanying flow due to the fibers, resistance to the liquid is increased, and thread breakage may occur. In addition, when the running speed of the fiber is high, it is possible to remove the liquid from the fiber by a method such as blowing air in a direction opposite to the running direction of the fiber after contacting with the liquid or pressing a rotation guide. It is preferable at the point which can suppress taking out of a liquid.

  Preferred components of the anti-fusing agent to be removed are the same as those of the anti-fusing agent attached before the solid phase polymerization described above, mainly composed of dimethylpolysiloxane, which contains a water-soluble salt and water-swellable. Most preferred is a mixture to which smectite is added. The liquid used for removal is preferably water, but it is surprising that dimethylpolysiloxane disperses well in water upon removal after solid-phase polymerization, despite its inherent lipophilicity. The reason for this is not clear, but it is presumed that dispersibility has been improved by decomposing dimethylpolysiloxane by low temperature heating by high temperature and long time heating in solid phase polymerization.

  The amount of adhesion of the anti-fusing agent after removal of the anti-fusing agent in the present invention is 4.0% by weight or less. In addition, the adhesion amount of the anti-fusing agent to the fiber indicates a value obtained by the method described in the examples. By setting the content to 4.0% by weight or less, it is possible to reduce deposition of the anti-fusing agent in the high-order processing step, and to improve the process passability. Since the effect increases as the adhesion amount decreases, it is more preferably 3.0% by weight or less, and further preferably 2.0% by weight or less. In addition, when a highly slippery component such as a polysiloxane compound is used as an anti-fusing agent, it can be used as an oil agent as it is, so it is preferable that the amount of adhesion is large to some extent, and the amount of adhesion is 0.1% by weight or more. Preferably, 0.5% by weight or more is more preferable.

  After removing the anti-fusing agent, it is a preferred embodiment to apply an oil or the like for improving the slipperiness. Known components can be used as the oil agent species. For example, a monohydric or polyhydric alcohol alkylene oxide block or random addition copolymer of a C1-C20 polyether compound or a terminal hydroxyl group of an alkyl group, a fatty acid, etc. Monohydric alcohol and monobasic aliphatic carboxylic acid esters such as polyether compounds, oleyl laurate, and oleyl oleate, monovalent alcohols such as dioctyl sebacate, dioleyl adipate, and polybasic aliphatic carboxylic acids Monohydric alcohols such as esters, dilauryl phthalate, trioleyl trimellitate and esters of aromatic carboxylic acids, polyhydric alcohols such as ethylene glycol diolate, trimethylolpropane tricaprylate, glycerin trioleate, bisphenol diolate Esters of basic aliphatic carboxylic acids, or alkylene oxide addition esters such as lauryl (EO) n octanoate as derivatives of these esters, mineral oils having a viscosity measured at 30 ° C. of 30 seconds or more in Redwood seconds, such as paraffins Can be used alone or in combination.

  In this case, when measuring the adhesion amount of the anti-fusing agent on the fiber after removal, the adhesion amount of the added oil or the like is also summed up, but everything that is finally adhered to the fiber is higher order. Since there is a possibility of dropping out in the process, and in the same way the process passability may be deteriorated, in the present invention, the amount of oil added after the removal of the anti-fusing agent is also the sum of the anti-fusing agent. Calculate as a quantity. That is, in the present invention, “the amount of adhesion of the anti-fusing agent to the fiber is 4.0% by weight or less” means that the amount of adhesion of the anti-fusing agent after removal and the adhesion of the added oil agent, etc. The total amount is 4.0% by weight or less based on the fiber weight. The total of the adhesion amount of the anti-fusing agent after removal and the adhesion amount of the added oil or the like is also determined by the method described in the examples.

  The removal rate of the anti-fusing agent in the removal step is preferably 10% or more, more preferably 20% or more, more preferably 30% or more, since higher fusion removal can achieve both prevention of fusion in solid-phase polymerization and improvement in passage through higher processing steps. Is more preferable. The removal rate in the present invention is a value determined by the method described in the examples. The upper limit of the removal rate is not particularly defined, but when a highly slippery component such as a polysiloxane compound is used as an anti-fusing agent, it can be used as it is as an oil agent, so it is not necessary to remove it excessively. The degree is sufficient.

  The polystyrene-equivalent weight average molecular weight (hereinafter referred to as molecular weight) of the liquid crystalline polyester fiber obtained in the present invention is preferably from 25 million to 1550,000. Having a high molecular weight of 255,000 or more, solid-phase polymerization is sufficiently advanced and has high strength, elongation, and elastic modulus to improve fabric performance. Thread breakage in higher-order processes can be suppressed, and wear resistance is improved. Moreover, since it has a high melting point, it has excellent heat resistance. Since these characteristics improve as the molecular weight increases, it is preferably 30 million or more, more preferably 350,000 or more. The upper limit of the molecular weight is not particularly limited, but the upper limit that can be reached in the present invention is about 1550,000. The molecular weight referred to in the present invention is a value determined by the method described in the examples.

  In the fiber obtained by the present invention, the heat of fusion (ΔHm1) at the endothermic peak (Tm1) observed when the differential calorimetry is measured at a temperature rising condition of 50 ° C. to 20 ° C./min is Tm1 + 20 after the observation of Tm1. After holding at a temperature of 5 ° C. for 5 minutes, the mixture is once cooled to 50 ° C. under a temperature drop condition of 20 ° C./min, and then the heat of fusion at the endothermic peak (Tm2) observed when measured again under a temperature rise condition of 20 ° C./min. It is preferably 3.0 times or more with respect to (ΔHm2), more preferably 4.0 times or more, and even more preferably 6.0 times or more.

  In this measurement method, ΔHm1 represents the degree of crystallization of the fiber (crystallinity), and ΔHm2 represents the degree to which the liquid crystal polyester constituting the fiber is crystallized in the process of re-heating after being once melted and cooled and solidified. When ΔHm1 is 3.0 times or more than ΔHm2, the degree of crystallinity of the fiber is sufficiently high, and high strength and elastic modulus can be obtained. However, if the crystallinity is excessively high, the toughness of the fiber is impaired and the workability is deteriorated. Therefore, ΔHm1 is preferably 15.0 times or less than ΔHm2. In the liquid crystalline polyester fiber of the present invention, there is one endothermic peak at the time of temperature increase and re-temperature increase under the above-described measurement conditions, but two or more peaks are observed depending on the structural change due to the solid phase polymerization conditions and the like. May be. In this case, ΔHm1 is a value obtained by summing the heat of fusion of all endothermic peaks in the temperature raising process, and ΔHm2 is a value obtained by summing the heat of fusion of all endothermic peaks in the reheating temperature process.

  The absolute value of ΔHm1 varies depending on the composition of the structural unit of the liquid crystal polyester, but is preferably 5.0 J / g or more, more preferably 6.0 J / g or more, and even more preferably 7.0 J / g or more. The larger ΔHm1, the higher the degree of crystallinity, the greater the strength and elastic modulus of the fiber, and the better the heat resistance. Therefore, the mechanical properties and heat resistance of products such as textiles can be improved, especially when the fineness is reduced. The process passability can be improved. The upper limit of ΔHm1 is not particularly limited, but the upper limit that can be achieved in the present invention is about 20 J / g.

  The fiber obtained by the present invention has a peak half width at Tm1 of less than 15 ° C, preferably less than 13 ° C. The peak half width in this measurement method represents the completeness of the crystal, and it can be said that the smaller the full width at half maximum, the higher the completeness of the crystal. High crystal integrity increases fiber strength and elastic modulus, improves heat resistance, and improves mechanical properties and heat resistance when made into textiles and other products, especially through finer process steps Can be improved. The lower limit of the peak half-value width is not particularly limited, but the lower limit that can be achieved in the present invention is about 3 ° C.

  Further, the melting point (Tm1) of the fiber obtained in the present invention is preferably 300 ° C. or higher, more preferably 310 ° C. or higher, and further preferably 320 ° C. or higher. By having such a high melting point, heat resistance and thermal dimensional stability are excellent. In the present invention, such a high melting point can be obtained by solid-phase polymerization of melt-spun fibers. Tm2 strongly reflects the melting point of the liquid crystal polyester polymer constituting the fiber. Therefore, the higher the Tm2, the higher the heat resistance of the polymer. In the fiber of the present invention, Tm2 is preferably 290 ° C or higher, more preferably 310 ° C or higher. The upper limits of Tm1 and Tm2 are not particularly limited, but the upper limit that can be reached in the present invention is about 400 ° C.

  The single fiber fineness of the fiber obtained in the present invention is preferably 18.0 dtex or less. By reducing the single fiber fineness to 18.0 dtex or less, the flexibility of the fiber is improved, the processability of the fiber is improved, and the surface area is increased, so that the adhesiveness with a chemical such as an adhesive is increased. In addition to having a monofilament made of monofilaments, there are advantages that the thickness can be reduced, the woven density can be increased, and the opening (area of the opening) can be widened. The single fiber fineness is more preferably 10.0 dtex or less, and even more preferably 7.0 dtex or less. The lower limit of the single fiber fineness is not particularly limited, but the lower limit that can be achieved in the present invention is about 1.0 dtex.

  Moreover, the fineness variation rate of the fiber obtained by the present invention is preferably 30% or less, more preferably 20% or less, and still more preferably 10% or less. The fineness fluctuation rate referred to in the present invention refers to a value measured by the method described in the examples. When the fineness variation rate is 30% or less, the uniformity in the longitudinal direction is increased, and the variation in fiber strength (product of strength and fineness) is also reduced. Since the variation is small, the uniformity of the opening (area of the opening) when the cocoon is made increases and the cocoon performance can be improved.

  The strength of the fiber obtained by the present invention is preferably 14.0 cN / dtex or more, more preferably 18.0 cN / dtex or more, and further preferably 20.0 cN / dtex or more. The elastic modulus is preferably 600 cN / dtex or more, more preferably 700 cN / dtex or more, and still more preferably 800 cN / dtex or more. The upper limits of the strength and elastic modulus are not particularly limited, but the upper limits that can be achieved in the present invention are a strength of about 30 cN / dtex and an elastic modulus of about 1500 cN / dtex. The strength referred to in the present invention refers to the tensile strength described in JIS L1013: 1999, and the elastic modulus refers to the initial tensile resistance. High strength can be expressed even when the fineness is set due to the high strength and elastic modulus, so that the weight and thickness of the fiber material can be reduced, and yarn breakage in higher processing steps such as weaving can be suppressed.

  The strength fluctuation rate of the fiber obtained in the present invention is preferably 20% or less, more preferably 15% or less. The strength referred to in the present invention refers to the strength at the time of cutting in the measurement of tensile strength described in JIS L1013: 1999, and the strength fluctuation rate refers to a value measured by the method described in the examples. When the strength variation rate is 20% or less, the uniformity in the longitudinal direction is increased, and the variation in fiber strength (the product of strength and fineness) is also reduced. It is also possible to suppress yarn breakage in the high-order processing step.

  The elongation of the fiber obtained in the present invention is preferably 2.0% or more. When the elongation is 2.0% or more, the impact absorbability of the fiber is increased, and the process passability and the handleability in the high-order processing step are excellent. The upper limit of elongation is not particularly limited, but the upper limit that can be reached in the present invention is about 10%.

  The compression elastic modulus in the direction perpendicular to the fiber axis (hereinafter referred to as compression elastic modulus) of the fiber obtained in the present invention is preferably 1.00 GPa or less, more preferably 0.50 GPa or less, and further preferably 0.35 GPa or less. The low compressive elastic modulus provides an effect of spreading the load by spreading the contact area when the fiber is pressed against the guide or ridge by a high-order processing step or a loom. Due to this effect, the pressing stress on the fiber is lowered and the wear resistance is improved. The lower limit of the compression modulus is not particularly limited, but if it is 0.10 GPa or more, the fiber is not crushed and deformed, and the quality of the product is not impaired. In addition, the compression elastic modulus said by this invention points out the value calculated | required by the method of an Example description.

  The fiber obtained by the present invention preferably has a thermal expansion coefficient of -20 to 0 ppm / ° C, more preferably -10 to 0 ppm / ° C. The thermal expansion coefficient referred to in the present invention refers to a value measured by the method described in the examples. Since the fiber of the present invention has a negative coefficient of thermal expansion and takes a low value of -20 to 0 ppm / ° C., the thermal dimensional stability is high, and high positional accuracy such as a circuit board base fabric and a circuit printing screen wrinkle is obtained. It can be suitably used for required applications.

  The birefringence (Δn) of the fiber obtained in the present invention is preferably from 0.250 to 0.450, more preferably from 0.300 to 0.400. If Δn is within this range, the molecular orientation in the fiber axis direction is sufficiently high, and high strength and elastic modulus can be obtained.

  The fiber obtained by the present invention preferably has a half width (Δ2θ) of a peak observed at 2θ = 18 to 22 ° in the equator direction with respect to the fiber axis in wide-angle X-ray diffraction is less than 1.8 °. More preferably, it is 6 ° or less. When Δ2θ is as small as less than 1.8 °, the completeness of the crystal is high, and the strength and elastic modulus are high, so that the process passability is enhanced. The lower limit of Δ2θ is not particularly limited, but the lower limit is about 0.8 °. In the present invention, Δ2θ refers to a value obtained by the method described in the examples.

  The abrasion resistance of the fiber obtained in the present invention is preferably 5 seconds or more, and more preferably 10 seconds or more. The abrasion resistance referred to in the present invention refers to a value measured by the method described in the examples. When the wear resistance is 5 seconds or more, the generation of fibrils due to rubbing in the high-order processing step of the liquid crystal polyester fiber can be suppressed, and the uniformity in the longitudinal direction and the process passability are improved. Moreover, in the cocoon made of monofilament, clogging of the opening due to the fibrils being woven into the cocoon can be suppressed.

  The fibers obtained in the present invention can have a wide number of filaments. The upper limit of the number of filaments is not particularly limited, but the number of filaments is preferably 50 or less, and more preferably 20 or less, in order to make the fiber product thinner and lighter. The present invention is particularly suitable for monofilaments having one filament. To improve the performance of monofilament filters and printing screens, it is particularly required to increase the weaving density and the opening area. For this purpose, the fineness and the strengthening to ensure weaving are particularly strong. It has been demanded. However, if only finer and higher strength can be obtained, it can be obtained by solid-phase polymerization of finer liquid crystalline polyester fiber. However, in the conventional technology, defects occur due to increased fusion due to solid weight accompanying finer fineness. Therefore, the uniformity in the longitudinal direction and the process passability were poor. The fibers obtained in the present invention can reduce defects due to fusion with an anti-fusing agent and can also improve process passability by subsequent removal.

  The liquid crystal polyester fiber obtained in the present invention has the characteristics of solid phase polymerized liquid crystal polyester fiber, such as high strength, high elastic modulus, high heat resistance, high thermal dimensional stability, and uniformity in the longitudinal direction. Widely used in the fields of general industrial materials, civil engineering / building materials, sports applications, protective clothing, rubber reinforcement materials, electrical materials (especially as tension members), acoustic materials, general clothing, etc. It is done. Effective applications include screen kites, filters, ropes, nets, fishnets, computer ribbons, printed circuit board base fabrics, paper canvases, air bags, airships, dome base fabrics, rider suits, fishing lines, various lines (Yachts, paragliders, balloons, kites), blind cords, support cords for screen doors, various cords for automobiles and aircraft, power transmission cords for electrical products and robots, etc. Examples of the monofilament used include a mesh fabric for a filter and a screen for printing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by this. The various characteristics of the present invention were evaluated by the following methods.

(1) Weight average molecular weight in terms of polystyrene (molecular weight)
A mixed solvent of pentafluorophenol / chloroform = 35/65 (weight ratio) was used as the solvent, and the solution was dissolved so that the concentration of the liquid crystal polyester was 0.04 to 0.08 weight / volume% to obtain a sample for GPC measurement. In addition, when there was an insoluble matter even after standing at room temperature for 24 hours, the mixture was left still for 24 hours, and the supernatant was used as a sample. This was measured using a GPC measuring apparatus manufactured by Waters, and the weight average molecular weight (Mw) was determined in terms of polystyrene.
Column: Two Shodex K-806M, one K-802 Detector: Differential refractive index detector RI (type 2414)
Temperature: 23 ± 2 ° C
Flow rate: 0.8 mL / min Injection volume: 200 μL
(2) Peak half-width at Tm1, Tm1 of liquid crystal polyester fiber, ΔHm1, Tc, ΔHc, Tm2, ΔHm2, melting point of liquid crystal polyester polymer Thermal analysis of the fiber was carried out by differential calorimetry with DSC2920 manufactured by TA instruments, and from 50 ° C. The temperature of the endothermic peak observed when measured under a temperature rising condition of 20 ° C./min was Tm1 (° C.), and the peak half-value width (° C.) and heat of fusion (ΔHm1) (J / g) at Tm1 were measured.

  Subsequently, after observing Tm1, the temperature of Tm1 + 20 ° C. is maintained for 5 minutes, and the temperature of the exothermic peak observed when measured under a temperature drop condition of 20 ° C./min is defined as Tc (° C.). (ΔHc) (J / g) was measured. Subsequently, the mixture was cooled to 50 ° C., and the endothermic peak observed when the temperature was again measured at 20 ° C./min was defined as Tm2, and the heat of fusion (ΔHm2) (J / g) at Tm2 was measured.

  In addition, about the liquid crystalline polyester polymer shown in the reference example, after observing Tm1, it was held at a temperature of Tm1 + 20 ° C. for 5 minutes, then cooled to 50 ° C. under a temperature decreasing condition of 20 ° C./minute, and again increased to 20 ° C./minute. The endothermic peak observed when measured under temperature conditions was defined as Tm2, and Tm2 was defined as the melting point of the polymer.

(3) Single fiber fineness and fineness variation rate 100 m of fiber was removed with a measuring machine, the weight (g) was multiplied by 100, and 10 measurements per level were performed, and the average value was defined as fineness (dtex). . The quotient obtained by dividing this by the number of filaments was defined as the single fiber fineness (dtex). The fineness variation rate was calculated by the following equation using the larger one of the absolute values of the difference between the maximum value and the minimum value from the average value of 10 finenesses.
Fineness fluctuation rate (%) = ((| maximum value or minimum value−average value | / average value) × 100)
(4) Strength, elongation, elastic modulus, and strength fluctuation rate According to the method described in JIS L1013: 1999, using Tensilon UCT-100 manufactured by Orientec Co., Ltd. under the conditions of a sample length of 100 mm and a tensile speed of 50 mm / min. The measurement was performed 10 times per average, and the average value was defined as strength (cN), strength (cN / dtex), elongation (%), and elastic modulus (cN / dtex). The strength fluctuation rate was calculated by the following formula using the larger one of the absolute values of the differences between the maximum and minimum values from the average value of 10 strengths.
Strong fluctuation rate (%) = ((| maximum or minimum value−average value | / average value) × 100)
(5) Thermal expansion coefficient At 50 ° C when TMA-50 manufactured by Shimadzu Corporation was used and a processing load of 0.03 cN / dtex was applied in the fiber axis direction and the temperature was increased from 40 ° C to 250 ° C at a rate of 5 ° C / min. The sample length L0 and the sample length L1 at 100 ° C. were used for calculation according to the following formula.
Thermal expansion coefficient (ppm / ° C.) = ((L1-L0) / (L0 × 50)) × 10 ⁶
(6) Compression modulus in the direction perpendicular to the fiber axis (compression modulus)
Place a single fiber on a highly rigid stage such as ceramic, and apply a compression load at a constant test speed using the indenter in the diameter direction under the following conditions with the side of the indenter approximately parallel to the fiber. After obtaining the load-displacement curve, the compression elastic modulus in the direction perpendicular to the fiber axis was calculated from the following equation.

  In the measurement, in order to correct the deformation amount of the device system, a load-displacement curve is obtained without placing the sample, and this is approximated by a straight line to calculate the deformation amount of the device with respect to the load. -From the displacement of each data point when the displacement curve was measured, the amount of deformation of the apparatus with respect to the load was subtracted to obtain the displacement of the sample itself, which was used for the following calculation.

  In the calculation, the compression elastic modulus was calculated using the load and displacement at two points where linearity is established in the load-displacement curve. The point on the low load side is a point where the load is about 30 mN because there is a possibility that the indenter does not hit the entire surface of the sample at the initial stage when the load is applied. However, when the low load point determined here is in the non-linear region, a straight line is drawn on the low load side along the load-displacement curve so as to pass the yield point, and the deviation between the straight line and the displacement is within 0.1 μm. The minimum load point is The high load side was a point with a load of about 100 mN. When the point on the high load side exceeds the yield point load, a straight line is drawn on the high load side along the load-displacement curve so as to pass the point on the low load side, and the displacement deviation from that line is zero. The point of maximum load within 1 μm was taken as the point on the high load side. In addition, l in the following formula is calculated as 500 μm, and the single fiber radius is a value obtained by measuring the diameter of the sample 10 times using an optical microscope before the test and halving the average diameter obtained by averaging this. Was used. Further, the load-displacement curve was measured 5 times for the sample 1 level, the compression elastic modulus was also calculated 5 times, and the average of these was taken as the compression elastic modulus.

Apparatus: Instron super precision material testing machine Model 5848
Indenter: Diamond flat indenter (square with a side of 500 μm)
Test speed: 50 μm / min Sampling speed: 0.1 second Data processing system: “Merlin” manufactured by Instron
Measurement atmosphere: At room temperature in air (23 ± 2 ° C., 50 ± 5% RH)
(7) Peak half-width (Δ2θ) in wide-angle X-ray diffraction
The fiber was cut into 4 cm, 20 mg of the fiber was weighed and used as a sample. The measurement was performed in the equator direction with respect to the fiber axis direction, and the conditions were as follows. At this time, the half width (Δ2θ) of the peak observed at 2θ = 18 to 22 ° was measured.
X-ray generator: Rigaku Denki 4036A2 type X-ray source: CuKα ray (using Ni filter)
Output: 40kV-20mA
Goniometer: Rigaku Denki 2155D type slit: 2mmφ-1 ° -1 °
Detector: Scintillation counter counting recording device: RAD-C type measurement range manufactured by Rigaku Corporation: 2θ = 5-60 °
Step: 0.05 °
Integration time: 2 seconds (8) Abrasion resistance A fiber loaded with a load of 2.45 cN / dtex (2.5 g weight / dtex) is hung vertically and is hard with a diameter of 3.8 mm so as to be perpendicular to the fiber. A chrome-satin-finished metal rod guide (bar guide manufactured by Yuasa Yindo Kogyo Co., Ltd.) was pressed at a contact angle of 2.7 °, and the guide was rubbed in the fiber axis direction at a stroke length of 30 mm and a stroke speed of 600 times / min. Observe and measure the number of seconds until the occurrence of white powder or fibrils is confirmed on the rod guide or on the fiber surface, and obtain the average value of 5 times excluding the maximum and minimum values from the 7 measurements. Wear resistance. The abrasion resistance was evaluated by the same test method for multifilaments.

(9) Birefringence (Δn)
Using a polarizing microscope (BLY-2 manufactured by OLYMPUS), measurement was performed 5 times per one sample level by the compensator method, and the average value was obtained.

(10) Adhesion amount of anti-fusing agent, removal rate 100 mg or more of fibers were collected, and the weight after drying for 10 minutes at 60 ° C. was measured (W0). Immerse the fibers in the dispersion medium, ultrasonically wash at room temperature for 20 minutes, wash the washed fibers with water, measure the weight after drying at 60 ° C. for 10 minutes (W1), and fuse according to the following formula The amount of inhibitor adhesion was calculated. The solvent or dispersion medium was the solvent or dispersion medium when the anti-fusing agent was applied as a solution or emulsion, and water otherwise. When water was used as a dispersion medium, sodium dodecylbenzenesulfonate as a surfactant was added to 2.0% by weight of water based on the fiber weight.
(Amount of adhesion preventive agent (% by weight)) = (W0−W1) × 100 / W1
Also, the removal rate is the amount of adhesion of the anti-fusing agent to the fiber (A0) before the removal step after solid-phase polymerization and the amount of adhesion of the anti-fusing agent to the fiber after removal (after adding an oil or the like) (A1). Was calculated from the time equation.
(Removal rate (%)) = (A0−A1) × 100 / A0
(11) Process passability A 50,000-meter fiber is applied to a ceramic rod guide having a diameter of 4 mm (bar guide manufactured by Yuasa Yido Michi Kogyo Co., Ltd .: material YM-99C, hardness 1800) at a contact angle of 90 ° while applying a fiber of 200,000 m / m. It was run in minutes and the process passability was evaluated from the state of deposits deposited on the guide. The evaluation criteria are as follows.

No fibril or scum accumulation is observed visually; Excellent (◎)
Fibrils and scum are observed, but there is no hindrance to fiber running; good (○)
Fibrils and scum are observed, causing yarn swings and yarn path fluctuations; Fail (△)
Fibrils and scum accumulated, evaluation stopped; Poor (×)
Reference example 1
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 870 parts by weight of p-hydroxybenzoic acid, 327 parts by weight of 4,4′-dihydroxybiphenyl, 89 parts by weight of hydroquinone, 292 parts by weight of terephthalic acid, 157 parts by weight of isophthalic acid Then, 1433 parts by weight of acetic anhydride (1.08 equivalent of the total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 330 degreeC in 4 hours.

  The polymerization temperature was maintained at 330 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference example 2
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 907 parts by weight of p-hydroxybenzoic acid, 457 parts by weight of 6-hydroxy-2-naphthoic acid, and 946 parts by weight of acetic anhydride (1.03 mol of the total phenolic hydroxyl group) Equivalent) was charged into a reaction vessel equipped with a stirring blade and a distillation tube, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, and then the reaction was carried out at 145 ° C. for 2 hours. Then, it heated up to 325 degreeC in 4 hours.

  The polymerization temperature was maintained at 325 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference example 3
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 808 parts by weight of p-hydroxybenzoic acid, 411 parts by weight of 4,4′-dihydroxybiphenyl, 104 parts by weight of hydroquinone, 314 parts by weight of terephthalic acid, 209 parts by weight of isophthalic acid Then, 1364 parts by weight of acetic anhydride (1.10 equivalents of the total phenolic hydroxyl groups) was charged, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 300 degreeC in 4 hours.

  The polymerization temperature was maintained at 300 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference example 4
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 323 parts by weight of p-hydroxybenzoic acid, 436 parts by weight of 4,4′-dihydroxybiphenyl, 109 parts by weight of hydroquinone, 359 parts by weight of terephthalic acid, 194 parts by weight of isophthalic acid Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 325 degreeC in 4 hours.

  The polymerization temperature was maintained at 325 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference Example 5
895 parts by weight of p-hydroxybenzoic acid, 168 parts by weight of 4,4′-dihydroxybiphenyl, 40 parts by weight of hydroquinone, 135 parts by weight of terephthalic acid, 75 parts by weight of isophthalic acid in a 5 L reaction vessel equipped with a stirring blade and a distillation tube Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 365 degreeC in 4 hours.

  The polymerization temperature was maintained at 365 ° C., the pressure was reduced to 133 Pa in 1.5 hours, the reaction was continued for another 20 minutes, and the polycondensation was completed when the torque reached 15 kgcm. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference Example 6
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 671 parts by weight of p-hydroxybenzoic acid, 235 parts by weight of 4,4′-dihydroxybiphenyl, 89 parts by weight of hydroquinone, 224 parts by weight of terephthalic acid, 120 parts by weight of isophthalic acid Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 340 degreeC in 4 hours.

  The polymerization temperature was maintained at 340 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference Example 7
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 671 parts by weight of p-hydroxybenzoic acid, 335 parts by weight of 4,4′-dihydroxybiphenyl, 30 parts by weight of hydroquinone, 224 parts by weight of terephthalic acid, 120 parts by weight of isophthalic acid Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 305 degreeC in 4 hours.

  The polymerization temperature was maintained at 305 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference Example 8
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 671 parts by weight of p-hydroxybenzoic acid, 268 parts by weight of 4,4′-dihydroxybiphenyl, 69 parts by weight of hydroquinone, 314 parts by weight of terephthalic acid, 30 parts by weight of isophthalic acid Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 355 degreeC in 4 hours.

  The polymerization temperature was maintained at 355 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

Reference Example 9
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 671 parts by weight of p-hydroxybenzoic acid, 268 parts by weight of 4,4′-dihydroxybiphenyl, 69 parts by weight of hydroquinone, 150 parts by weight of terephthalic acid, 194 parts by weight of isophthalic acid Then, 1011 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) was added, and the temperature was raised from room temperature to 145 ° C. over 30 minutes with stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 310 degreeC in 4 hours.

  The polymerization temperature was maintained at 310 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the torque reached 15 kgcm, the polycondensation was completed. Next, the inside of the reaction vessel was pressurized to 0.1 MPa, the polymer was discharged to a strand through a die having one circular discharge port having a diameter of 10 mm, and pelletized by a cutter.

  The characteristics of the liquid crystalline polyester obtained in Reference Examples 1 to 9 are shown in Table 1. Each resin was heated and heated in a nitrogen atmosphere on a hot stage, and the transmitted light of the sample was observed under polarized light. As a result, optical anisotropy (liquid crystallinity) was confirmed. The melt viscosity was measured using a Koka flow tester at a temperature of melting point + 10 ° C. and a shear rate of 1000 / s.

Example 1
After vacuum drying at 160 ° C. for 12 hours using the liquid crystalline polyester of Reference Example 1, it was melt extruded with a φ15 mm single-screw extruder (heater temperature 290 to 340 ° C.) manufactured by Osaka Seiki Co., Ltd. and measured with a gear pump. However, the polymer was supplied to the spinning pack. The spinning temperature from the extruder to the spinning pack at this time was 345 ° C. In the spinning pack, the polymer is filtered using a metal nonwoven fabric filter (WLF-10 manufactured by Watanabe Yoshikazu Co., Ltd.), and the discharge rate is 3.0 g / min from a die having five holes with a hole diameter of 0.13 mm and a land length of 0.26 mm ( The polymer was discharged at a rate of 0.6 g / min per single hole.

  The discharged polymer is allowed to pass through a 40 mm heat-retaining region, and then cooled and solidified from the outside of the yarn with an annular cooling air. Thereafter, an oil containing polydimethylsiloxane as a main component is applied, and all the 5 filaments are 1200 m / min. I took it to 1 godet roll. The spinning draft at this time is 32. After passing this through the second godet roll at the same speed, four of the five filaments are sucked with a suction gun, and the remaining one is a pirn winder through the dancer arm (no contact roll contacting the winding package). Was wound up into the shape of a pan. During the winding time of about 100 minutes, yarn breakage did not occur and the yarn making property was good. Table 2 shows the physical properties of the spun fiber. The oil adhesion amount was 1.0% by weight. Table 2 shows the spinning conditions and the physical properties of the spun fiber.

A winding machine (ET-68S controlled winding by Kozu Seisakusho Co., Ltd.) that unwinds fibers from the spun fiber package in the longitudinal direction (perpendicular to the fiber circulation direction) and keeps the speed constant without using a speed control roller. Machine). At this time, polydimethylsiloxane (PDMS, SH200 manufactured by Toray Dow Corning Co., Ltd.) uses 5.0% by weight water emulsion as an anti-fusing agent, and uses a stainless steel roll (OR) with a satin finish before the winder. Went. Also, the core material for rewinding is a stainless steel perforated bobbin wound with Kevlar felt (weight per unit: 280 g / m ² , thickness 1.5 mm). The package form is a taper end winding with a taper angle of 30 °. Not used, the traverse guide and the fiber contact point were 5 mm from the fiber package, the wind number was 9.0, and the traverse width was always oscillated by modifying the taper width adjusting mechanism. Table 3 shows the winding tension, the rewinding speed, the winding amount, the adhesion amount of the anti-fusing agent, and the winding density.

  Using a closed oven, the temperature was raised from room temperature to 240 ° C. in about 30 minutes, held at 240 ° C. for 3 hours, and then raised to 295 ° C., the final temperature reached at 4 ° C./hour, Furthermore, solid state polymerization was performed under the condition of maintaining at 295 ° C. for 15 hours. The atmosphere was supplied with dehumidified nitrogen at a flow rate of 25 NL / min, and exhausted from the exhaust port so that the interior was not pressurized.

  The obtained solid-state polymerization package is attached to a feeding device that can be rotated by an inverter motor, and the fiber is sent in the transverse direction (fiber circulation direction) at a yarn feeding speed of about 200 m / min. When it was wound up by a fast winder, the entire amount could be unwound without breaking the yarn. While this fiber is unwound in the longitudinal direction again, water of 40 ° C. is put in a water bath with a bath length of 100 cm (contact length of 100 cm), and a bubbling device (holes with a diameter of about 0.3 mm at intervals of about 2 cm is formed inside the water bath. An open nylon tube with an outer diameter of 6 mm was disposed, and 0.1 MPa of air was introduced into the tube, and the solid-phase polymerized fiber was allowed to pass at a speed of 100 m / min while passing through a nip roll. After that, a water emulsion (emulsion concentration: 4% by weight) of an emulsifier mainly composed of a polyether compound and an emulsifier composed mainly of a lauryl alcohol is used as a finishing oil, and lubrication is performed using a satin finish stainless steel roll before the winder. And wound up with a winder (ET type controlled winder manufactured by Kozu Seisakusho). The properties of the obtained fiber (solid weight, unraveling, fiber properties after washing) are shown in Table 3. The high molecular weight, high strength, high elastic modulus, high melting point, which are the characteristics of solid-phase polymerized liquid crystal polyester fiber, It can be seen that it has a high ΔHm1, has a fineness variation rate and a strong variation rate, and is excellent in longitudinal uniformity. In addition, Δn of this fiber was 0.35, and it had a high orientation, and its thermal expansion coefficient was −7 ppm / ° C., and it had excellent thermal dimensional stability. The results of evaluating the process passability using this fiber are also shown in Table 3. It can be seen that the process passability is excellent.

Comparative Example 1
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. The fiber properties are shown in Table 3 (solid, unraveled, washed fiber properties). This was evaluated for process passability without washing. The results are shown in Table 3, and the evaluation was stopped because yarn breakage occurred when scum caused by the anti-fusing agent was deposited on the guide during the evaluation and unwinding was performed for about 40,000 m.

  In this way, when the adhesion amount of the anti-fusing agent is large, the uniformity in the longitudinal direction of the fiber is high as can be seen from the fineness fluctuation rate and the strong fluctuation rate, but the process passability is poor due to the deposition of the anti-fusing agent. I understand.

Comparative Example 2
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. While unwinding this again, the bottom surface of the nylon felt roll (outer diameter 80 mm) is brought into contact with a bath containing water at room temperature (25 ° C.) and rotated at a rotational speed of 5.3 rpm to make the surface water. The fibers were brought into contact with the wet cleaning roll at a speed of 200 m / min so as to have a contact length of 2 cm, passed through the nip roll, and then finished oil was applied and wound up in the same manner as in Example 1. Table 3 shows the properties of the obtained fibers (solid weight, unraveling, and fiber properties after washing). Table 3 shows the evaluation results of the process passability using this fiber. Although thread breakage did not occur, scum was deposited on the guide, and the yarn path was not constant and was rejected.

  Even when washing is performed in this manner, it is understood that the process passability is poor when the adhesion amount of the fiber anti-fusing agent is large.

Examples 2 and 3
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. Washing and finishing oil application were performed in the same manner as in Example 1 except that the liquid temperature and the traveling speed were set as described in Table 3. Table 3 shows the obtained fiber properties (solid weight, unraveling, and fiber properties after washing). It can be seen that the removal rate is higher when the liquid temperature is higher and the contact time is longer than in Example 1. Although the process passability evaluation results of these fibers are also described in Table 3, the process passability was excellent.

Example 4
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. This was washed in the same manner as in Example 1 except that a polyester non-woven fabric having a thickness of 2.27 mm and a basis weight of 215 g / m ² was installed on the liquid surface, and the fibers were passed through the lower side of the non-woven fabric to come into contact with the non-woven fabric. A finishing oil was applied. Table 3 shows the obtained fiber properties (solid weight, unraveling, and fiber properties after washing). It can be seen that the removal rate is higher when there is an object in contact with the fiber in the liquid bath as compared with Example 1. Although the process passability evaluation results of these fibers are also described in Table 3, the process passability was excellent.

Examples 5 and 6
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. This was performed without bubbling, with a bath length of 150 cm (contact length 150 cm), and in the same manner as in Example 4 except that a polyester nonwoven fabric was placed on the liquid surface, and washing and applying a finishing oil was performed. It was. At this time, in Example 5, a mixture of 50% by volume of acetone as water was added as a liquid, and in Example 6, a surfactant (polyoxyethylene alkyl ether, fatty acid alkanolamide, sodium alkyl ether sulfate ester in water as liquid) It was set as the mixture which added 0.2 volume% of "Natera" (trademark) made from Lion Corporation. The liquid temperature and running speed were the conditions shown in Table 3, respectively.

  The physical properties of the obtained fibers are shown in Table 3. It can be seen that the removal rate is improved as compared with Comparative Example 2 by adjusting the washing conditions even when the traveling speed is increased. The process passability evaluation results of these fibers are also shown in Table 3. In Example 5, the process passability is excellent, and in Example 6, although scum is generated, there is no hindrance to the fiber running and the process passability is observed. Was good.

Example 7
Spinning, rewinding, solid phase polymerization, and unwinding were performed in the same manner as in Example 1 to obtain liquid crystal polyester fibers. Using a water tank with a bath length of 100 cm, a free roller with an outer diameter of 30 mm is arranged outside the water tank, and the fiber passes through the free roller through the bathtub three times in total (contact length 300 cm). Washing was performed using a mixture of water and a surfactant, with the liquid temperature and the treatment speed as shown in Table 3. Further, after the washing, the finishing oil was applied in the same manner as in Example 1.

  Although the physical properties of the obtained fiber are described in Table 3, it can be seen that the removal rate is greatly improved by adjusting the cleaning conditions even when the traveling speed is increased. The process passability evaluation results of these fibers are also shown in Table 3, but the process passability was excellent.

Examples 8 and 9
Spinning was performed under the same conditions as in Example 1 except that the discharge amount and the number of nozzle holes were set as shown in Table 2, and all the spun filaments were collected to obtain a multifilament. Table 2 shows the physical properties of the obtained fiber. This was rewound by the same method as in Example 1 except that the winding amount was 60,000 m and the wind number was 12.1. Table 3 shows the winding tension, adhesion amount of the anti-fusing agent, and winding density. This was subjected to solid phase polymerization and unwinding in the same manner as in Example 1.

  Next, the entire package after unraveling is immersed in an ultrasonic cleaner filled with 0.05% by volume of a surfactant (“Natera” (registered trademark) manufactured by Lion Corporation) in 40 ° C. warm water. , Ultrasonic cleaning for 15 minutes was performed 6 times. Thereafter, the fibers were unwound in a state where the package was not dried, and washing and finishing oil application were performed in the same manner as in Example 1.

  Although the physical properties of the obtained fibers and the process passability evaluation results are listed in Table 3, it can be seen that the anti-fusing agent can be removed by washing even in the case of multifilaments and the process passability is excellent.

Examples 10 and 11
Spinning was performed under the same conditions as in Example 1 except that the discharge amount, the nozzle hole diameter, the land length, and the spinning speed were set as shown in Table 2. Table 2 shows the physical properties of the obtained fiber. This was rewound by the same method as in Example 1 except that the winding amount was 60,000 m. Table 4 shows the winding tension, adhesion amount of the anti-fusing agent, and winding density at this time. This was subjected to solid weight, unraveling, washing, and finishing oil application in the same manner as in Example 1.

  Although the physical properties of the obtained fibers and the process passability evaluation results are listed in Table 4, it can be seen that the anti-fusing agent can be removed by washing even if the single fiber fineness is different, and the process passability is excellent. .

Example 12
Spinning was performed under the same conditions as in Example 1 except that the discharge amount, the nozzle hole diameter, and the land length were set as shown in Table 2. At this time, a 100 mm heating cylinder (insulating region 100 mm) was provided under the base, and this temperature was set to 200 ° C. Although thread breakage occurred at the start of spinning, when threading was performed again, winding for about 100 minutes was possible. Table 2 shows the physical properties of the obtained fiber. This was rewound by the same method as in Example 1 except that the winding amount was 60,000 m and the wind number was 4.5. Table 4 shows the winding tension, adhesion amount of the anti-fusing agent, and winding density at this time. This was subjected to solid weight, unraveling, washing, and finishing oil application in the same manner as in Example 1. The yarn breakage occurred once during unwinding.

  Although the physical properties and process passability evaluation results of the obtained fibers are shown in Table 4, it can be seen that the anti-fusing agent can be removed by washing even if the single fiber fineness is small, and the process passability is excellent.

Example 13
Spinning was performed under the same conditions as in Example 12 except that the discharge amount, the number of nozzle holes, and the spinning speed were set as shown in Table 2. Although thread breakage occurred at the start of spinning, when threading was performed again, winding for about 100 minutes was possible. Table 2 shows the physical properties of the obtained fiber. Using this as an anti-fusing agent, polydimethylsiloxane (PDMS, SH200 manufactured by Toray Dow Corning) is 4.0% by weight, and hydrophilic smectite (“Lucentite (registered trademark) SWN” manufactured by Co-op Chemical) is 0.2%. Rewinding was performed in the same manner as in Example 12 except that a water% water emulsion was used. Table 4 shows the winding tension, adhesion amount of the anti-fusing agent, and winding density at this time. This was solidified and unwound in the same manner as in Example 1. Since the yarn breakage occurred once during the unwinding, the yarn breakage did not occur after the unwinding speed of 50 m / min. Thereafter, washing and finishing oil application were performed in the same manner as in Examples 8 and 9.

  Although the physical properties of the obtained fibers and the process passability evaluation results are listed in Table 4, even when the single yarn fineness is 2.5 dtex, the anti-fusing agent can be removed by washing, and the process passability is It turns out that it is favorable.

Examples 14-21
Spinning was carried out in the same manner as in Example 10 except that the resins of Reference Examples 2 to 9 were used and the spinning temperature was set as shown in Table 5. In Example 17 using the resin of Reference Example 5, yarn breakage occurred at the start of spinning, but when threading was performed again, winding for about 100 minutes was possible. Table 5 shows the physical properties of the obtained fiber. This was wound up in the same manner as in Example 10. Table 4 shows the winding tension, adhesion amount of the anti-fusing agent, and winding density at this time. Solid phase polymerization was carried out in the same manner as in Example 1 except that the final ultimate temperature of solid phase polymerization was set as described in Table 4. This was unwound, washed and applied with a finishing oil in the same manner as in Example 1.

  Although the physical properties of the obtained fibers and the process passability evaluation results are described in Table 4, the anti-fusing agent can be removed by washing even if the resin composition is different, and the process passability is excellent or good. I understand.

Claims (5)

  After the solid phase polymerization is performed by attaching an anti-fusing agent to the liquid crystal polyester fiber, the anti-fusing agent is removed while the solid phase polymerized liquid crystal polyester fiber is running, and the amount of adhesion of the anti-fusing agent to the fiber is reduced. The manufacturing method of the liquid-crystal polyester fiber characterized by being 4.0 weight% or less with respect to a weight.   2. The method for producing a liquid crystal polyester fiber according to claim 1, wherein the removal rate of the anti-fusing agent is 10% or more.   3. The method for producing a liquid crystalline polyester fiber according to claim 1, wherein the fiber is brought into contact with a liquid capable of dissolving or dispersing the anti-fusing agent to remove the anti-fusing agent.   4. The method for producing a liquid crystal polyester fiber according to claim 3, wherein the liquid is water.   The method for producing a liquid crystal polyester fiber according to any one of claims 1 to 4, wherein the liquid crystal polyester fiber is a monofilament.