JP2014167174A - Liquid crystal polyester fiber and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal polyester fiber which has high strength and a high elastic modulus, causes less fusion between fibers, is excellent in step passability in high-order processing step and adhesiveness to e.g. resins and is formed by solid phase polymerization.SOLUTION: A method of producing a liquid crystal polyester fiber comprises applying an inorganic particle (A) and a phosphoric acid based compound (B) to yarn obtained by melt spinning of a liquid crystal polyester, subjecting the resultant body to solid phase polymerization and cleaning. With the adhesion ratio of the phosphoric acid based compound (B) as (b) wt.%, the method meets the condition b≥26. A liquid crystal polyester fiber obtained by the method is also provided.

Description

  The present invention relates to a liquid crystal polyester fiber having high strength and high elastic modulus, and excellent process passability and post-processability, and a method for producing the same.

  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. It is also known that liquid crystalline polyesters have increased molecular weight due to solid phase polymerization and increased melting point, so that heat resistance and dimensional stability are improved (for example, 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.

  Liquid crystal polyester fibers are commonly used for industrial materials. When fishing nets and ropes are used, nets and ropes are used, and when used as monofilaments for screen rods and filters, weaving is performed. In such high-order processing, the liquid crystalline polyester fiber is inferior in wear resistance, so that the fiber is cracked (fibrillated) due to friction with the yarn guide or the roller, so that reduction of surface friction is required.

  In addition, when the final product is used, the tension member and the resin / rubber reinforcing agent have a step of bonding to the matrix resin, but the liquid crystal polyester fiber is required to have improved adhesion.

  It is known that the formation of irregularities on the fiber surface is effective for reducing the surface friction of the fiber and improving the adhesion, and is also applied to liquid crystal polyester fibers. In Patent Document 1, gentle irregularities are formed on the surface of the core-sheath composite spinning by making the sheath component a blend of liquid crystalline polyester and flexible thermoplastic. Although this technique can surely form surface irregularities, it is necessary to make the sheath component a blend of two components, so that debris at the interface generates and deposits debris called scum, which deteriorates process passability. The quality of the fabric may be impaired. In addition, since components other than liquid crystal polyester are essential, unevenness is likely to occur in the fiber, and in high-order processing, there is a problem that the weaving property is impaired due to the occurrence of thread breakage starting from that.

  By the way, the solid phase polymerization of the liquid crystalline polyester is generally performed at a high temperature that does not exceed the melting point. Therefore, it is important to provide a solid phase polymerization oil for the purpose of preventing fusion of yarns.

  On the other hand, the solid phase polymerization oil agent becomes a scrap called scum by being deposited on a guide, a roller, etc. in the process after the solid phase polymerization process, and causes problems such as deterioration of process passability due to tension fluctuation. Remaining solid-phase polymerization oil in the fiber deteriorates the post-processability, for example, when applying a resin as a tension member (coating), or when performing chemical or resin impregnation as a resin or rubber reinforcement. There was a problem.

For example, Patent Documents 2 and 3 disclose techniques for suppressing sticking between fibers by applying inorganic particles having high heat resistance to the fiber surface. Although this technique is certainly effective in suppressing sticking, the inorganic particles adhere firmly to the fiber surface or between the fibers, and the excessively adhered inorganic particles easily fall off from the fiber surface, resulting in poor post-processability. There was a problem.
Patent Documents 4 and 5 disclose techniques for suppressing fusion between fibers by using inorganic particles and polysiloxane for fibers after melt spinning. Although it has been shown in this technique that a combination of inorganic particles and polysiloxane exhibits a high effect in suppressing fusion (Patent Document 4), it has been found that the polysiloxane used in combination has a problem.

  That is, polysiloxane undergoes gelation due to cross-linking reaction between polysiloxanes under solid-state polymerization conditions, and this gelled product adheres firmly to the fiber surface. During processing, it was found that scum accumulates on the guide and the roller and deteriorates the process passability. In addition, the polysiloxane gelled product has high tackiness, and when it is deposited as scum, it causes a large fluctuation in tension due to the adhesive force with the fiber.

  Furthermore, since the gelated product of polysiloxane adheres firmly to the fiber surface, it has also been found that it remains on the fiber even when mechanical cleaning such as ultrasonic cleaning is performed in addition to cleaning with a surfactant. From this, the problem of deteriorating the post-processability of the fiber, particularly the adhesiveness, has been clarified.

  Therefore, in order to avoid such problems caused by polysiloxane, Patent Document 6 discloses a technique for suppressing fusion between fibers and improving process passability by using inorganic particles and a phosphoric acid compound. Has been.

  Phosphoric acid compounds undergo dehydration and decomposition of organic components under solid-state polymerization conditions to form phosphate condensation salts that can be easily removed from fibers with inorganic particles by washing with water. , Scum accumulation in the next process is reduced, and process passability is improved.

  However, since the fiber surface is smooth, there is room for further improvement in post-processability, particularly adhesion to the chemical solution or resin, due to the influence of the contact area with the chemical solution or resin.

  Thus, the compatibility of the high-order processing passability and adhesiveness of the liquid crystal polyester fiber has been a problem.

JP 11-81031 A (page 5) JP 2004-107826 A (page 2) JP 2006-336147 A (page 6) JP 2009-228177 A (second page) JP 2008-240229 A (15th and 16th pages) International Publication No. 2012 / 132855A1 (23rd, 24th pages)

Edited by Technical Information Association, “Modification of liquid crystal polymer and latest applied technology” (2006) (pages 235-256)

  The object of the present invention is high-strength and high-elastic modulus, less fusion between fibers, excellent processability in high-order processing, and solid-phase polymerization excellent in adhesion to resins and the like It is in providing a liquid crystal polyester fiber and its manufacturing method.

  The present inventors have focused on the solid-phase polymerization process, which is important when obtaining liquid crystal polyester fibers, and optimized the type and amount of oil for solid-phase polymerization to deal with the above-mentioned problems. It has been found that fine irregularities can be formed on the fiber surface during solid-phase polymerization, and that the oil agent for solid-phase polymerization can be easily washed in a subsequent step, leading to the present invention.

That is, the object of the present invention is achieved by the following means.
(1) In a method for producing a liquid crystal polyester fiber, a solid phase polymerization is performed after applying inorganic particles (A) and a phosphoric acid compound (B) to a yarn obtained by melt spinning a liquid crystal polyester. When the adhesion rate of the acid compound (B) is (b) wt%,
b ≧ 26
The manufacturing method of the liquid crystalline polyester fiber characterized by satisfy | filling.
(2) Liquid crystal polyester fiber obtained by the production method described in the above item (1).

  Since the liquid crystalline polyester fiber of the present invention has high strength and high elastic modulus, there is little fusion between the fibers, and it is excellent in process passability in a high-order processing step, and further has excellent adhesion to a resin, etc. The productivity of textile products can be increased. In particular, it is excellent in adhesiveness with a chemical solution or resin when used as a tension member, resin or rubber reinforcement. In addition, because product defects due to product pull-in and scum mixing can be suppressed and the product yield can be improved, for filters and screen 織物 applications that require high mesh fabrics, weaving density is increased to improve performance. (High meshing), large area of opening (opening), reduction of defects in opening, and improvement of weaving can be achieved. Moreover, the liquid crystalline polyester fiber of the present invention can be efficiently produced by the production method of the present invention.

  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 (i) a polymer of aromatic oxycarboxylic acid, (ii) a polymer of aromatic dicarboxylic acid and aromatic diol, aliphatic diol, and (iii) aromatic oxycarboxylic acid. , A polymer composed of an aromatic dicarboxylic acid, an aromatic diol, and an aliphatic diol, and the like. Among these, a polymer composed only of an aromatic is preferable. Polymers composed only of aromatics exhibit excellent strength and elastic modulus when made into fibers. Moreover, conventionally well-known method can be used for the polymerization prescription of liquid crystalline polyester.

  Here, examples of the aromatic oxycarboxylic acid include hydroxybenzoic acid, hydroxynaphthoic acid and the like, or alkyl, alkoxy and halogen substituted products thereof.

  Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, and the like, or alkyl, alkoxy, and halogen substitution thereof. Examples include the body.

  Furthermore, examples of the aromatic diol include hydroquinone, resorcin, dihydroxybiphenyl, naphthalene diol, and the like, or alkyl, alkoxy, and halogen-substituted products thereof. Examples of the aliphatic diol include ethylene glycol, propylene glycol, and butanediol. And neopentyl glycol.

  Preferred examples of the liquid crystal polyester used in the present invention include a liquid crystal polyester obtained by copolymerizing a p-hydroxybenzoic acid component and a 6-hydroxy-2-naphthoic acid component, a p-hydroxybenzoic acid component and 4,4′-dihydroxybiphenyl. Examples thereof include liquid crystal polyester in which a component, an isophthalic acid component and / or a terephthalic acid component are copolymerized, and a p-hydroxybenzoic acid component, a 4,4′-dihydroxybiphenyl component, an isophthalic acid component, and a terephthalic acid component are particularly preferable. Examples thereof include liquid crystal polyester in which a hydroquinone component is copolymerized.

  With the combination as described above, the symmetry of the molecular chain is lowered, so that the melting point of the liquid crystal polyester is lowered below the decomposition point and has a melting point capable of melt spinning. Therefore, the fiber has a good spinning property at the spinning temperature set between the melting point of the polymer and the thermal decomposition temperature, and a uniform fiber is obtained in the longitudinal direction. The rate can be increased. In the present invention, a liquid crystal polyester composed of structural units (I), (II), (III), (IV) and (V) represented by the following chemical formula is 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. The combination of the above (I) to (V) is preferable because it has high linearity and can increase the elastic modulus.

  Combining components made of diols that are not bulky and highly linear, such as structural units (II) and (III), the molecular chain has an ordered and less disturbed structure, and the crystallinity is not excessively high. Interaction in the direction perpendicular to the axis can also be maintained. Thereby, in addition to obtaining high strength and elastic modulus, particularly excellent wear resistance can be obtained by performing high-temperature heat treatment after solid-phase polymerization.

  The structural unit (I) is preferably 40 to 85 mol%, more preferably 65 to 80 mol%, still more preferably 68 to 75 mol% with respect to the total of the structural units (I), (II) and (III). It is. 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% with respect to 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, wear resistance can be improved by performing high temperature heat processing after solid-phase polymerization.

  The structural unit (IV) is preferably 40 to 95 mol%, more preferably 50 to 90 mol%, still more preferably 60 to 85 mol% with respect to 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 it has good spinnability at a spinning temperature set between the melting point of the polymer and the thermal decomposition temperature, so that a uniform fiber can be obtained in the longitudinal direction. Since the linearity of the polymer is moderately disturbed, the fibril structure is easily disturbed by the high-temperature heat treatment after the solid phase polymerization, and the interaction in the direction perpendicular to the fiber axis is increased, thereby improving the wear resistance.

  In addition, the preferable range of each structural unit of liquid crystalline polyester preferably used by the said invention is as follows. The total of the following structural units (I) to (V) is 100 mol%. The liquid crystal polyester fiber of the present invention can be suitably obtained by adjusting the composition within this range.

Structural unit (I): 45 to 65 mol%
Structural unit (II): 12-18 mol%
Structural unit (III): 3 to 10 mol%
Structural unit (IV): 5 to 20 mol%
Structural unit (V): 2 to 15 mol%
Furthermore, the total amount of the structural unit (IV) and the structural unit (V) and the total amount of the structural unit (II) and the structural unit (III) are preferably substantially equimolar.

  In addition, the liquid crystal polyester used in the present invention can be copolymerized with other monomers in addition to the above monomers as long as the liquid crystallinity is not impaired. For example, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid Aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and the like, polyethers such as polyethylene glycol, polysiloxane, aromatic iminocarboxylic acid, aromatic diimine, and aromatic hydroxyimine It is done.

  In addition, other polymers can be added to and used in combination with the liquid crystalline polyester used in the present invention as long as the effects of the present invention are not impaired. Addition / combination means mixing two or more polymers, using one component or two or more components partially mixed in a composite spinning of two or more components, or using all of them. Say. Examples of other polymers include polyester, vinyl polymers such as polyolefin and polystyrene, polycarbonate, polyamide, polyimide, polyphenylene sulfide, polyphenylene oxide, polysulfone, aromatic polyketone, aliphatic polyketone, semi-aromatic polyesteramide, and polyether. Polymers such as ether ketone and fluororesin 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 Preferred examples include phthalate, polycyclohexanedimethanol terephthalate, and polyester 99M. In addition, when these polymers are added and used in combination, the melting point thereof is preferably within the melting point of liquid crystal polyester ± 30 ° C. in order not to impair the yarn-forming property. In addition, in order to improve the strength and elastic modulus of the obtained fiber, and to suppress the generation of fluff and yarn breakage due to peeling at the polymer interface, the amount added and used is preferably 50% by weight or less, and 5% by weight or less Is more preferable, and it is most preferable that no other polymer is added or used in combination.

  The liquid crystalline polyester used in the present invention includes various metal oxides, inorganic substances such as kaolin and silica, colorants, matting agents, flame retardants, antioxidants and ultraviolet absorbers within the range not impairing the effects of the present invention. In addition, additives such as infrared absorbers, crystal nucleating agents, fluorescent brighteners, end group capping agents, and compatibilizers may be contained in small amounts.

  The melting point of the liquid crystalline polyester used in the present invention is preferably 200 to 380 ° C. in order to widen the temperature range in which melt spinning is possible, and more preferably 250 to 360 ° C. in order to improve the spinnability. The melting point of the liquid crystal polyester polymer is a value measured by the method described in the examples.

  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. By setting the molecular weight to 30,000 or more, it has an appropriate viscosity at the spinning temperature and can improve the spinning property. The higher the molecular weight, the higher the strength, elongation and elastic modulus of the resulting fiber, but if the molecular weight is too high, the viscosity will be high and the fluidity will be poor, and eventually it will not flow, so the molecular weight is preferably less than 25 million, More preferably less than 20 million. Here, the weight average molecular weight in terms of polystyrene refers to a value measured by the method described in the examples.

  The liquid crystalline polyester used in the present invention is preferably dried before being subjected to melt spinning in order to suppress foaming due to water mixing and to improve the yarn-making property. Moreover, since the monomer which remain | survives in liquid crystalline polyester can also be removed by performing vacuum drying, a yarn-making property can be improved further and it is more preferable. As drying conditions, vacuum drying at 100 to 200 ° C. for 8 to 24 hours is usually used.

  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, is guided to a base. At this time, the temperature from the polymer pipe to the die (spinning temperature) is preferably not less than the melting point of the liquid crystal polyester, and more preferably not less than the melting point of the liquid crystal polyester + 10 ° C. in order to improve fluidity. However, if the spinning temperature is excessively high, the viscosity of the liquid crystal polyester increases, leading to deterioration of fluidity and yarn-making property. Therefore, the temperature is preferably 500 ° C. or less, and more preferably 400 ° C. or less. 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 discharging, it is preferable to reduce the diameter of the mouthpiece hole and to increase the land length (the length of the straight pipe portion that is the same as the diameter of the mouthpiece hole) from the viewpoint of improving the yarn-making property and improving the uniformity of the fineness. However, when the hole diameter is excessively small, clogging of the hole is likely to occur, and the diameter is preferably 0.05 mm or more and 0.50 mm or less, and more preferably 0.10 mm or more and 0.30 mm or less. 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. preferable.

  In order to maintain uniformity, the number of holes in one die is preferably 500 holes or less, and more preferably 100 holes or less. The lower limit of the number of holes may be one hole. In addition, it is preferable that the introduction hole located immediately above the die hole is a straight hole in terms of not increasing pressure loss. In order to suppress abnormal stagnation, it is preferable that the connecting portion between the introduction hole and the die hole is tapered.

  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 500 m / min or more in order to reduce productivity and single yarn fineness. The liquid crystalline polyester mentioned as a preferred example in the present invention has a suitable spinnability at the spinning temperature, so that the take-up speed can be increased, and 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-up speed by the discharge linear speed is preferably 1 or more and 500 or less, and more preferably 10 or more and 100 or less from the viewpoint of improving the spinning property and improving the uniformity of the fineness.

  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 ones can be used. However, it is generally used in terms of improving the unwinding property when unwinding the fiber obtained by melt spinning in the rewinding step before the solid phase polymerization (hereinafter referred to as the spinning yarn). It is preferable to use a typical spinning oil agent or a mixed oil agent of inorganic particles (A) / phosphoric acid compound (B) described later.

  Winding can be carried out using a known winding machine to form a package such as pirn, cheese, corn, etc. However, wrapping with a roller that does not contact the surface of the package during winding does not give the fiber a frictional force. It is preferable in that it is not fibrillated.

  The present invention is characterized in that solid-phase polymerization is performed after applying inorganic particles (A) and a phosphoric acid compound (B) to liquid crystal polyester fibers. In addition to the effect of suppressing fusion occurring between fibers during solid phase polymerization by applying inorganic particles (A) and phosphoric acid compound (B), the component is thermally denatured in the solid phase polymerization step. It excels in process passability in the post-process, and is excellent in post-processability when making a product. In the present invention, since the inorganic particles (A) and the phosphoric acid compound (B) are used as the oil for solid phase polymerization, the oil component is not used, but the inorganic particles (A) and the phosphoric acid compound (B) are also used. Expressed as “oil agent for solid phase polymerization”.

  The inorganic particles (A) in the present invention are known inorganic particles, and examples include minerals, metal hydroxides such as magnesium hydroxide, metal oxides such as silica and alumina, and carbonates such as calcium carbonate and barium carbonate. In addition to compounds, sulfate compounds such as calcium sulfate and barium sulfate, carbon black and the like can be mentioned. By applying such heat-resistant inorganic particles onto the fibers, it is possible to reduce the contact area between the single yarns and avoid the fusion that occurs during solid phase polymerization.

  The inorganic particles (A) are easy to handle in consideration of the coating process, are preferably easy to disperse in water from the viewpoint of reducing the environmental load, and are preferably inert under solid-state polymerization conditions. From these viewpoints, it is preferable to use silica or silicate. In the case of a silicate, a phyllosilicate having a layered structure is particularly preferable. Examples of phyllosilicates include kaolinite, halloyite, serpentine, siliceous ore, smectite group, granite, talc, and mica. Of these, talc and mica are considered in view of availability. Most preferably, is used.

  Moreover, as a median diameter (D50) of an inorganic particle (A), 10 micrometers or less are preferable. This is because, by setting D50 to 10 μm or less, the probability that the inorganic particles (A) are held between the fibers is increased, and the fusion suppressing effect becomes remarkable. For the same reason, D50 is more preferably 5 μm or less. In addition, the lower limit of D50 is preferably 0.01 μm or more in consideration of the cost and the detergency in the washing step after solid phase polymerization. The median diameter (D50) here is a value measured by the method described in the examples.

  In addition, as the phosphoric acid compound (B) in the present invention, compounds represented by the following chemical formulas (1) to (3) can be used.

Here, R ₁ and R ₂ are hydrocarbons, M ₁ is an alkali metal, M ₂ is any one of an alkali metal, hydrogen, a hydrocarbon, and an oxygen-containing hydrocarbon.

  Note that n represents an integer of 1 or more. The upper limit of n is preferably 100 or less, more preferably 10 or less, from the viewpoint of suppressing thermal decomposition.

As R ₁ , in consideration of the gas generated by thermal decomposition during solid phase polymerization, it is preferable that the structure does not contain a phenyl group, and more preferably an alkyl group, from the viewpoint of reducing the environmental load. The carbon number of R ₁ is preferably 2 or more from the viewpoint of affinity for the fiber surface, and suppresses the weight loss rate due to decomposition of the organic component accompanying solid phase polymerization, and is generated by decomposition during solid phase polymerization. Is preferably 20 or less from the viewpoint of preventing the remaining on the fiber surface.

R ₂ is preferably a hydrocarbon having 5 or less carbon atoms from the viewpoint of solubility in water, and more preferably 2 or 3 carbon atoms.

M ₁ is preferably sodium or potassium from the viewpoint of production cost.

  By using the phosphoric acid compound (B) in combination with the inorganic particles (A), the dispersibility of the inorganic particles (A) can be increased, enabling uniform application to the fibers, and exhibiting an excellent anti-fusing effect. Since the inorganic particles (A) can be prevented from sticking to the fiber surface, the residual amount of the inorganic particles (A) on the fibers after washing is reduced, and the effect of suppressing the occurrence of scum in the subsequent processing step. Is expressed. In addition, the inventors of the present application have made extensive studies, and the phosphate compound (B) is subjected to a dehydration reaction and the organic component contained in the phosphate compound (B) is decomposed under solid-state polymerization conditions, thereby causing phosphate. From the formation of this condensation salt, it was found that it can be easily removed from the fiber with water in the washing step after solid phase polymerization. On the other hand, when the phosphoric acid compound (B) is applied alone, the decontamination property of the condensed salt causes the phosphate to absorb moisture and deliquesce on the fiber surface even under normal fiber storage conditions, resulting in a decrease in detergency. Also confirmed. That is, it has been found that excellent detergency is expressed only when the inorganic particles (A) and the phosphoric acid compound (B) are used in combination. As a mechanism for expressing this excellent detergency, since the inorganic particles (A) have hygroscopicity when the inorganic particles (A) are used in combination, the condensed salt of the phosphoric acid compound (B) naturally absorbs moisture. It is presumed that the condensed salt of the phosphoric acid compound (B) expands by absorbing water only when passing through water, preventing deliquescence, and peels off in layers from the fiber surface together with the inorganic particles (A). .

  In order to uniformly apply the inorganic particles (A) and the phosphoric acid compound (B) with an appropriate amount of adhesion, use a mixed oil obtained by adding the inorganic particles (A) to the diluted solution of the phosphoric acid compound (B). It is preferable to use water as the diluent from the viewpoint of safety. From the viewpoint of suppressing fusion, the concentration of the inorganic particles (A) in the diluted solution is desirably high and is preferably 0.01% by weight or more, more preferably 0.1% by weight or more. To 10% by weight or less, more preferably 5% by weight or less. The concentration of the phosphoric acid compound (B) is desirably high from the viewpoint of uniform dispersion of the inorganic particles (A), and is 0.1% by weight or more, more preferably 1.0% by weight or more. The upper limit of the concentration of the phosphoric acid compound (B) is not particularly limited, but is preferably 50% by weight or less for the purpose of avoiding excessive adhesion due to an increase in the viscosity of the mixed oil agent and adhesion spots due to an increase in temperature dependency of the viscosity. More preferably, it is 30% by weight or less.

  In addition, as a method of applying the inorganic particles (A) and the phosphoric acid compound (B) to the fiber, it may be performed from melt spinning to winding, but in order to increase the adhesion efficiency, melt spinning is performed. It is preferable that the wound yarn is applied to the yarn while being rewound, or a small amount is adhered by melt spinning, and the wound yarn is additionally applied while being rewound.

  The adhering method may be a guide oiling method, but in order to uniformly adhere to fine fibers such as monofilaments, adhering with a metal or ceramic kiss roll (oiling roll) is preferable. In addition, when a fiber is a cake shape and a tow shape, it can apply | coat by immersing in a mixed oil agent.

  In the present invention, when the adhesion rate of the inorganic particles (A) to the fiber is (a) wt% and the adhesion rate of the phosphate compound (B) is (b) wt%, the phosphate compound (B) The adhesion rate (b) is 26% by weight or more. As a result of intensive studies, the inventors of the present invention formed a concavo-convex on the fiber surface by subjecting it to a solid phase polymerization step in a state where the adhesion rate (b) of the phosphate compound (B) was 26% by weight or more, and the yarn surface It has been found that since the frictional resistance is reduced, the passability in the subsequent process is improved, and the specific surface area of the fiber is increased to improve the adhesion to the resin. The reason for forming the irregularities is considered to be due to the decomposition of the fiber surface by the phosphoric acid compound (B). That is, the phosphoric acid compound (B) is obtained by performing a solid phase polymerization reaction at a high temperature for a long time in a state where the phosphoric acid compound (B) is attached to the surface of the liquid crystalline polyester fiber. Does not penetrate into the inside of the fiber, but only the liquid crystalline polyester present on the very surface of the yarn is accelerated by the phosphoric acid compound (B) to lower the molecular chain, and is removed along with the solid-phase polymerization oil in the subsequent washing step. As a result, irregularities are formed on the yarn surface. In this way, according to the production method of the present invention, the liquid crystal polyester inside the fiber is not affected by the decomposition, so that the surface of the fiber is formed without damaging the excellent strength and elastic modulus of the liquid crystal polyester fiber. It is possible.

Here, when the fiber is observed from a microscopic viewpoint, the adhesion rate of the phosphoric acid compound to the fiber actually varies slightly in the longitudinal direction of the fiber and between the filaments. For the purpose, as described in the Examples, the target fiber is observed to observe a total of 20 surface forms of 5 mm in length and count the number of yarns having irregularities on the surface of the yarn over the entire sampled length of 5 mm. went. In addition, when there is a portion where there is no unevenness in the sampled length of 5 mm, if the maximum length of the portion where there is no unevenness does not continuously exceed 1 mm, the entire sampled length of 5 mm Including the number of yarns with unevenness on the surface of the yarn, the length of the portion with no unevenness exceeding 1 mm was excluded from the number. In addition, it is important in terms of adhesiveness that the yarn surface has irregularities throughout the entire length of 5 mm. The greater the number, the better the adhesion.
As described above, the unevenness of the fiber surface is estimated from the reaction between the liquid crystalline polyester present on the very surface of the yarn and the phosphoric acid compound (B). It was thought that the number of yarns with unevenness gradually increased as the adhesion rate (b) increased. Interestingly, the number of yarns with unevenness suddenly increased when the amount became 26% by weight or more from 26% by weight. Became clear. That is, when the adhesion rate (b) of the phosphoric acid compound (B) is around 26% by weight, there is a mixture of uneven portions and uneven portions in the longitudinal direction of one fiber. The maximum length of the part where there is no unevenness at the boundary does not exceed 1 mm continuously, so that the number of threads with unevenness is rapidly increased, and the adhesiveness to the resin is greatly improved. It became clear. When the state of the fiber is considered at a micro level for this phenomenon, the adhesion rate (b) of the phosphate compound (B) is observed locally, although there are some adhesion spots of the phosphate compound (B) in the longitudinal direction. It is presumed that the adhesiveness is improved because the number of sites where the amount becomes 26% by weight or more increases, and the portion with less unevenness becomes less than 26% by weight.
On the other hand, when the adhesion rate (b) of the phosphoric acid compound is less than 26% by weight, the number of smooth yarns where irregularities are not formed on the yarn surface increases, and the number of yarns where irregularities are observed on the yarn surface over the entire length of 5 mm. Is drastically reduced. For this reason, the frictional resistance with the guides in the subsequent process is increased, and the fibrillation is liable to occur by rubbing, and the adhesiveness with the resin is remarkably lowered. That is, since the portion where the adhesion rate (b) of the phosphoric acid compound (B) is less than 26% by weight increases over the entire fiber, the liquid crystal polyester on the surface of the yarn by the phosphoric acid compound (B) proceeds, but falls off. Since the molecular weight is not lowered as much as possible, the number of places where the smoothness of the yarn surface is maintained even after the washing step is increased, and it is assumed that the adhesiveness of the whole fiber is drastically lowered because the adhesiveness is poor at this place.
The adhesion rate (b) of the phosphoric acid compound (B) is preferably more than 30% by weight, more preferably 35% by weight or more, from the viewpoint of forming irregularities uniformly in the longitudinal direction of the fiber. . The upper limit is approximately 95% by weight or less from the viewpoint of suppressing adhesion spots in the longitudinal direction.

In addition, although the oil component adhesion rate (a + b) of the solid phase polymerization oil agent exceeds 26% by weight, the solid phase polymerization is performed by attaching a large amount of oil component exceeding 26% by weight. A high inhibitory effect on the fusion of fibers is obtained. The greater the oil adhesion rate (a + b) of the solid phase polymerization oil agent, the higher the fusing suppression effect. Therefore, the oil adhesion rate is preferably 35% by weight or more, and more preferably 40% by weight or more. On the other hand, if the oil adhesion rate is too high, the fiber becomes sticky and the washability after the solid weight process is lowered to increase the amount of scum. Therefore, it is preferably 100% by weight or less, more preferably 80% by weight or less. The oil adhesion rate (a + b) of the solid phase polymerization oil to the fiber refers to the value of the oil adhesion rate obtained by the technique described in the examples for the fiber after application of the solid phase polymerization oil.
Moreover, it is preferable that the following conditions are satisfied for the adhesion rate (a) wt% of the inorganic particles (A) and the adhesion rate (b) wt% of the phosphoric acid compound (B).
Condition 1. a ≧ 0.01
Condition 2. b / a ≧ 1
Under Condition 1, the adhesion rate (a) of the inorganic particles (A) is 0.01% by weight or more, so that the effect of suppressing the fusion caused by the inorganic particles becomes remarkable. The upper limit of the adhesion rate (a) is approximately 10% by weight or less from the viewpoint of uniform adhesion.

In condition 2, by forming the adhesion rate (b) of the phosphoric acid compound (B) to be equal to or higher than the adhesion rate (a) of the inorganic particles (A), condensation salt formation during solid phase polymerization of the phosphoric acid compound (B) The excellent detergency derived from the above appears more remarkably, and is also preferable from the viewpoint of suppressing sticking and dropping between the inorganic particles (A) and the fibers.
Here, the adhesion rate (a) of the inorganic particles (A) and the adhesion rate (b) of the phosphoric acid compound (B) refer to values calculated by the following equations.
(Adhesion rate of inorganic particles (A) (a)) = (a + b) × Ca ÷ (Ca + Cb)
(Adhesion rate of phosphoric acid compound (B) (b)) = (a + b) × Cb ÷ (Ca + Cb)
Here, Ca indicates the concentration of the inorganic particles (A) in the solid phase polymerization oil, and Cb indicates the concentration of the phosphoric acid compound (B) in the solid phase polymerization oil.

  In the present invention, solid phase polymerization is performed after coating the inorganic particles (A) and the phosphoric acid compound (B). By performing solid phase polymerization, the molecular weight is increased, thereby increasing strength, elastic modulus, and elongation. Solid-phase polymerization can be processed in the form of a cake, tow (for example, carried on a metal net), or continuously as a thread between rollers, but the equipment can be simplified and productivity can be improved. It is preferable to carry out in the form of a package in which fibers are wound around a core from the point.

  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 core materials. 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.

When the endothermic peak temperature of the liquid crystal polyester fiber subjected to solid phase polymerization is defined as Tm ₁ (° C.), the maximum attainment temperature is preferably 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. Incidentally, Tm ₁ referred to herein is generally a melting point of liquid crystal polyester fiber, in the present invention indicates a value determined by the measuring method described in Examples. It is preferable that the maximum temperature be less than Tm ₁ (° C.) in order to prevent fusion. Further, it is more preferable to raise the solid-phase polymerization temperature stepwise or continuously with respect to time because it can prevent fusion and increase the time efficiency of solid-phase polymerization. In this case, 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 about Tm ₁ + 100 ° C. of the liquid crystal polyester fiber before the solid phase polymerization. However preventing maximum temperature enhances the solid phase polymerization rate be less than Tm 1 _-60 of the fiber after solid phase polymerization (℃) than Tm 1 _(℃) and fused in the solid phase polymerization in this case It is preferable from the point which can be performed.

  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 molecular weight, that is, strength, elastic modulus, and elongation of the fiber. On the other hand, the effects of increasing the strength, elastic modulus, and elongation are saturated with the elapsed time.

  In the present invention, from the viewpoint of improving process passability and product yield in the weaving process, washing is performed after solid-phase polymerization. By removing the solid-phase polymerization oil agent for preventing fusion by washing, deterioration of the process passability due to deposition on the guide of the solid-phase polymerization oil agent in the subsequent process, for example, weaving process, the deposit to the product It is possible to suppress generation of defects due to mixing.

  The cleaning method includes a method of wiping the fiber surface with cloth or paper, but fibrillation occurs when a mechanical load is applied to the solid-phase polymerized yarn, so that the fiber is immersed in a liquid that can dissolve or disperse the solid-phase polymerized oil. The method is preferred. A method of blowing off using a fluid in addition to immersion in a liquid is more preferable because the solid-phase polymerization oil swollen by the liquid can be efficiently removed.

  The liquid used for cleaning is preferably water in order to reduce the environmental load. The higher the temperature of the liquid, the higher the removal efficiency. The temperature is preferably 30 ° C or higher, more preferably 40 ° C or higher. However, if the temperature is too high, the liquid will evaporate significantly, so the boiling point of the liquid is preferably −20 ° C. or lower, more preferably the boiling point of −30 ° C. or lower.

  A surfactant is preferably added to the liquid used for cleaning from the viewpoint of improving cleaning efficiency. The addition amount of the surfactant is preferably 0.01 to 1% by weight, more preferably 0.1 to 0.5% by weight in order to increase the removal efficiency and reduce the environmental load.

  Furthermore, in order to increase the cleaning efficiency, it is preferable to impart vibration or a liquid flow to the liquid used for cleaning. In this case, there is a method of ultrasonically vibrating the liquid, but it is preferable to apply a liquid flow from the viewpoint of simplifying the equipment and saving energy. There are liquid flow application methods such as stirring in the liquid bath and liquid flow application at the nozzle, but it can be easily implemented by supplying with the nozzle when circulating in the liquid bath. Is preferred.

  The degree of removal of the solid-phase polymerization oil agent by washing is appropriately adjusted according to the purpose, but the solid phase remaining in the washed fiber from the viewpoint of improving the processability of the fiber in the higher processing and weaving processes and improving the quality of the fabric. The oil adhesion rate of the polymerized oil is preferably 2.0% by weight or less, more preferably 1.0% by weight or less, and most preferably 0.5% by weight or less. In addition, the adhesion rate of a residual solid heavy oil agent refers to the value calculated | required by the method of an Example description about the fiber wound up immediately after the washing | cleaning process.

  Since washing increases the throughput per unit time, the fibers may be immersed in liquid in the form of a cake, tow, or package, but the fibers are continuously removed for uniform removal in the fiber longitudinal direction. It is preferable to immerse in the liquid while running. The method of continuously immersing the fiber in the liquid may be a method of guiding the fiber into the bath using a guide or the like, but in order to suppress fibrillation of the solid-phase polymerized fiber due to contact resistance with the guide, slits are provided at both ends of the bath. It is preferable to allow the fiber to pass through the slit through the slit and not to provide a yarn path guide in the bath.

  When the packaged solid-phase polymerized yarn is continuously run, the fibers are unwound, but in order to suppress fibrillation when peeling the slight fusion caused by solid-phase polymerization, the solid-phase polymerized package is used. It is preferable that the yarn is unwound by so-called side cutting, in which the yarn is unwound in the direction perpendicular to the rotation axis (fiber wrapping direction) while being rotated.

  Such unwinding methods include a method of actively driving at a constant rotation speed using a motor, etc., a method of speed-control unwinding while controlling the rotation speed using a dancer roller, and a solid-state polymerization package on a free roll. Then, a method of unwinding while pulling the fiber with a speed control roller can be mentioned. A method of immersing the liquid crystal polyester fiber in a liquid in a package state and unwinding it as it is is a preferable embodiment because the oil component can be efficiently removed.

  In addition, it is preferable that the fluid used when blowing off using a fluid is air or water. In particular, when air is used as the fluid, it is possible to expect the effect of drying the liquid crystal polyester fiber surface, so that it is possible to prevent the accumulation of dirt in the subsequent process, that is, the yield can be improved. Therefore, this is a preferred embodiment.

  Moreover, since the liquid used for washing | cleaning has adhered to the liquid crystal polyester fiber surface after washing | cleaning, it is also a preferable aspect. If the liquid used for cleaning remains on the surface of the liquid crystal polyester fiber, it will eventually dry and become foreign matter on the yarn surface, so that the surface of the liquid crystal polyester fiber can be made more uniform by rinsing. It is possible to suppress fluctuations in the unwinding tension.

  The fluid used for rinsing is preferably water. Rinsing is performed for the purpose of removing the cleaning liquid component adhering to the surface of the liquid crystal polyester fiber, so that it is possible to perform cleaning efficiently by using water capable of dissolving the component. It is also a preferred embodiment to warm water for the purpose of increasing the solubility of the component. The upper temperature is not particularly limited because the higher the temperature, the higher the solubility and the higher the efficiency of rinsing, so the energy consumption required for heating should be reduced and the energy cost reduced. Considering the loss due to evaporation, 80 ° C. is a good guideline.

  It becomes a more preferable aspect by combining the removal of the water | moisture content which remained on the liquid-crystal polyester fiber surface by blowing off after rinsing.

In addition, when it is necessary to improve the abrasion resistance of the fiber depending on the purpose of use of the liquid crystal polyester fiber such as a screen wrinkle or a monofilament for a filter, it is preferable to perform a high temperature heat treatment at a temperature of Tm ₁ + 10 ° C. or higher after washing. Incidentally, Tm ₁ here refers to a value obtained by a measuring method described in Examples. Tm ₁ is the melting point of the fiber, but when the liquid crystal polyester fiber is heat-treated at a high temperature of melting point + 10 ° C. or higher, the peak half width at Tm ₁ becomes 15 ° C. or higher, and the crystallinity of the whole fiber and the completeness of the crystal are improved. By reducing it, the wear resistance is greatly improved.

In terms of heat treatment, there is solid-state polymerization of liquid crystalline polyester fibers, but if the treatment temperature in this case is not lower than the melting point of the fibers, the fibers will be fused and melted. In the case of solid-phase polymerization, the melting point of the fiber increases with the treatment, so the final solid-phase polymerization temperature may be equal to or higher than the melting point of the fiber before the treatment. It is lower than the melting point, that is, the melting point of the fiber after heat treatment. That is, the high temperature heat treatment here is not solid phase polymerization, but reduces the structural difference between the dense crystalline portion and the amorphous portion formed by solid phase polymerization, that is, the degree of crystallinity and completeness of the crystal. The wear resistance is improved by reducing the property. Thus also the processing temperature changes is Tm ₁ by heat treatment, preferably greater than or equal to Tm 1 ₊ 10 ° C. of the treated fiber, the process temperature from this point be Tm 1 ₊ 10 ° C. or more fibers after treatment Preferably, Tm ₁ + 40 ° C. or higher is more preferable, Tm ₁ + 60 ° C. or higher is further preferable, and Tm ₁ + 80 ° C. or higher is particularly preferable. The upper limit of the treatment temperature is the temperature at which the fibers are melted, and is about Tm ₁ + 300 ° C. although it varies depending on the tension, speed, single fiber fineness, and treatment length.

Another heat treatment is the thermal stretching of liquid crystalline polyester fiber, but the thermal stretching is to tension the fiber at high temperature, the fiber structure has higher molecular chain orientation, the strength and elastic modulus increase, and the crystallization The degree of crystal integrity is maintained, that is, ΔHm ₁ remains high, and the peak half-width of Tm ₁ remains small. Accordingly, the heat treatment of the present invention aims to improve the wear resistance by reducing the crystallinity (decreasing ΔHm ₁ ) and decreasing the crystal perfection (increasing peak half-value width), resulting in a fiber structure inferior in wear resistance. Is different. The high temperature heat treatment referred to in the present invention does not increase the strength and elastic modulus because the crystallinity is lowered.

  The high temperature heat treatment is preferably performed while continuously running the fibers because fusion between the fibers can be prevented and the uniformity of the treatment can be improved. At this time, non-contact heat treatment is preferably performed in order to prevent generation of fibrils and perform uniform treatment. Heating means include atmospheric heating and radiant heating using laser and infrared rays, but heating with a slit heater using a block or plate heater has both the effects of atmospheric heating and radiant heating, increasing the stability of processing. Therefore, it is preferable.

  The treatment time is preferably longer in order to lower the crystallinity and crystal perfection, preferably 0.01 seconds or more, more preferably 0.05 seconds or more, and further preferably 0.1 seconds or more. Further, the upper limit of the treatment time is preferably 5.0 seconds or less, more preferably 3.0 seconds or less, because the equipment load is reduced, and if the treatment time is long, the orientation of the molecular chain is relaxed and the strength and elastic modulus are lowered. Preferably, it is 2.0 seconds or less.

  When the fiber tension at the time of processing is excessively high, fusing is likely to occur, and when heat treatment is performed in an excessive tension state, the effect of improving wear resistance is low because the decrease in crystallinity is small. It is preferable to make the tension as low as possible. This is clearly different from thermal stretching. However, if the tension is low, the fiber travel becomes unstable and the treatment becomes non-uniform, so 0.001 cN / dtex or more and 1.0 cN / dtex or less is preferable, and 0.1 cN / dtex or more and 0.3 cN / dtex or less. More preferred.

  When heat treatment is performed while running, the tension is preferably as low as possible, but stretching and relaxation may be added as appropriate. However, if the tension is too low, the fiber travel becomes unstable and the treatment becomes non-uniform, so the relaxation rate is preferably 2% or less (stretching ratio 0.98 times or more). Also, when the tension is high, fusing due to heat is likely to occur, and when heat treatment is performed in an excessive tension state, the reduction in crystallinity is small and the effect of improving wear resistance is low. Depending on the temperature, it is preferably less than 10% (stretching ratio: 1.10 times). More preferably, it is less than 5% (stretching ratio: 1.05 times), more preferably less than 3% (1.03 times). The draw ratio is defined as a quotient obtained by dividing the second roller speed by the first roller speed when the heat treatment is performed between the rollers (between the first roller and the second roller).

  Although the treatment speed depends on the treatment length, the higher the speed, the higher the temperature and short time treatment becomes possible, and the effect of improving wear resistance is further enhanced, and the productivity is also improved, preferably 100 m / min or more, more preferably 200 m / min or more, More preferably, it is 300 m / min or more. The upper limit of the processing speed is about 1000 m / min from the running stability of the fiber.

  The treatment length depends on the heating method, but in the case of non-contact heating, it is preferably 100 mm or more, more preferably 200 mm or more, and even more preferably 500 mm or more in order to perform uniform treatment. In addition, if the treatment length is excessively long, processing unevenness and fiber fusing occur due to yarn swinging inside the heater, and therefore it is preferably 3000 mm or less, more preferably 2000 mm or less, and even more preferably 1000 mm or less.

  In addition, it is preferable to perform above-described washing | cleaning and heat processing within one continuous process, without winding up in the middle once. When winding liquid crystal polyester fiber after solid-phase polymerization in particular, fiber fibrillation occurs due to abrasion with a winder, etc., so that after washing, heat treatment is subsequently performed to increase wear resistance. preferable.

  Moreover, it is preferable to apply a finishing oil from the viewpoint of improving process passability in subsequent processes such as washing and heat treatment. As the finishing oil, a finishing oil generally used for polyester fibers can be preferably applied, but it is more preferable that the finishing oil does not contain particles from the viewpoint of suppressing fluctuations in running tension due to dropping during the process.

  The oil adhesion rate of the finishing oil is preferably 0.1% by weight or more with respect to the fiber in order to exert effects such as lubricity by the finishing oil, and is 3 for the purpose of preventing soiling in the post-processing step due to excessive application. 0.0% or less is preferable. The oil adhesion rate of the finishing oil referred to here is obtained by subtracting the value of the oil adhesion rate of the residual solid-phase polymerization oil of the fiber from the value of the oil adhesion rate obtained by the method described in the examples for the fiber after the finishing oil is applied. Value.

  Next, the liquid crystal polyester fiber obtained by the production method of the present invention will be described in detail.

  The number of filaments of the fiber of the present invention can be arbitrarily selected according to the use of the fiber product. For example, the number of filaments is preferably 50 or less, more preferably 20 or less, in order to reduce the thickness and weight of the fiber product. In particular, since the monofilament having 1 filament is a field in which it is strongly desired to suppress the occurrence of scum during weaving and to improve the adhesion with a resin during plate making, the fiber of the present invention can be used particularly suitably. Further, in the reinforcing material application, it is preferable that the number of filaments is large from the viewpoint of productivity, but if the number of filaments is excessively large, the handleability is inferior, so the upper limit is about 5000.

  The single fiber fineness of the fiber of the present invention is preferably 18.0 dtex or less. The single fiber fineness referred to here is a value obtained by the method described in the examples. By reducing the single fiber fineness to 18.0 dtex or less, the molecular weight of the polymer constituting the fiber is easily increased when solid-phase polymerization is performed in the fiber state, and the strength, elongation, and elastic modulus are improved. In addition to having the properties of improving the flexibility of the fiber and improving the processability of the fiber, increasing the surface area and improving the adhesion with chemicals such as adhesives, in addition to the case of a cocoon made of monofilament There are also advantages that the thickness can be reduced, the weave 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 by the above-described manufacturing method is about 1.0 dtex.

  The strength of the fiber of the present invention is preferably 12.0 cN / dtex or more, more preferably 14.0 cN / dtex or more, and further preferably 15.0 cN / dtex or more in order to increase the strength of the final product such as woven fabric or knitted fabric. The upper limit of the strength is not particularly limited, but the upper limit that can be reached by the above-described manufacturing method is about 30.0 cN / dtex. In addition, the intensity | strength said here is the value calculated | required by the method of an Example description.

  The elongation of the fiber of the present invention is preferably 1.0% or more, and more preferably 2.0% or more. When the elongation is 1.0% or more, the impact absorbability of the fibers is increased, the process passability and the handleability in the high-order processing step are excellent, and the impact absorbability is increased, so that the wear resistance is also increased. The upper limit of elongation is not particularly limited, but the upper limit that can be reached by the above-described manufacturing method is about 10.0%. Here, the elongation is a value obtained by the method described in the examples.

  The elastic modulus is preferably 500 cN / dtex or more, more preferably 600 cN / dtex or more, and further preferably 700 cN / dtex or more in order to increase the elastic modulus of the fabric. The upper limit of the elastic modulus is not particularly limited, but the upper limit that can be reached by the above-described manufacturing method is about the elastic modulus of 1500 cN / dtex. The elastic modulus in the present invention is a value obtained by the method described in the examples.

  High strength and elastic modulus make it suitable for applications such as ropes, tension members and other reinforcing fibers, printing screens, filter meshes, etc. And thinning can be achieved, and yarn breakage in higher processing steps such as weaving can be suppressed.

The liquid crystal polyester fiber of the present invention has a peak half-value width of 15 ° C. or more in an endothermic peak (Tm ₁ ) observed when measured under a temperature rising condition of 50 ° C. to 20 ° C./min in differential calorimetry. preferable. Tm ₁ in this measurement method represents the melting point of the fiber, and the peak shape is higher in crystallinity as the area is larger, that is, as the heat of fusion ΔHm ₁ is larger, and as the half value width is narrower, the completeness of the crystal is higher. I can say that. Liquid crystalline polyesters are spun and then subjected to solid-phase polymerization to increase Tm ₁ , increase ΔHm ₁ , decrease half-width, and increase crystallinity and crystal perfection to increase fiber strength, elongation, and elasticity. The rate is increased and the heat resistance is improved. On the other hand, the wear resistance deteriorates, but this is thought to be due to the fact that the structural difference between the crystal part and the amorphous part becomes remarkable due to the increase in crystal perfection, so that the interface breaks down. Therefore, in the fiber of the present invention, while maintaining the high Tm ₁ , high strength, elongation, and elastic modulus, which are characteristics of the solid phase polymerized fiber, the peak half-value width is 15 like that of a liquid crystal polyester fiber not solid phase polymerized. By increasing to a value above ℃, the crystallinity is lowered, the crystal / amorphous structural difference that is the starting point of fracture is reduced, the fibril structure is disturbed, and the entire fiber is softened, thereby improving the wear resistance. It is preferable to increase. The peak half width at Tm ₁ is more preferably 20 ° C. or higher because higher wear resistance is higher. The upper limit is not particularly limited, but the upper limit that can be industrially reached is about 80 ° C.

  In the liquid crystal polyester fiber of the present invention, there is one endothermic peak, but two or more peaks may be observed depending on the fiber structure, such as when solid phase polymerization is insufficient. In this case, the peak half-value width is the sum of the half-value widths of the respective peaks.

The melting point (Tm ₁ ) of the fiber of the present invention is preferably 300 ° C. or higher, more preferably 310 ° C. or higher, and further preferably 320 ° C. or higher. Since it has such a high melting point, heat resistance and thermal dimensional stability are excellent, so that it can be processed at a high temperature even after it is made into a product, and post-processability is excellent. The upper limit of Tm ₁ is not particularly limited, but the upper limit that can be reached in the present invention is about 400 ° C.

The value of heat of fusion ΔHm ₁ varies depending on the composition of the structural unit of the liquid crystal polyester, but is preferably 6.0 J / g or less. ΔHm ₁ is reduced to 6.0 J / g or less, the crystallinity is lowered, the fibril structure is disturbed, the entire fiber is softened, and the crystal / amorphous structural difference that is the starting point of fracture is reduced. Improves wear resistance. As ΔHm ₁ is lower, the wear resistance is improved, so 5.0 J / g or less is more preferable. The lower limit of ΔHm ₁ is not particularly limited, but 0.5 J / g or more is preferable in order to obtain high strength and elastic modulus.

When the liquid crystalline polyester fiber is solid-phase polymerized, the molecular weight is increased and the strength, elongation, elastic modulus, and heat resistance are improved. At the same time, the crystallinity is increased and ΔHm ₁ is increased. When the degree of crystallinity increases, the strength, elongation, elastic modulus, and heat resistance are further improved, but the structural difference between the crystal part and the amorphous part becomes remarkable, the interface is easily broken, and the wear resistance is lowered. . On the other hand, it has high molecular weight, which is one of the characteristics of solid-phase polymerized fibers, and maintains high strength, elongation, elastic modulus, and heat resistance, and is low like liquid crystal polyester fibers that are not solid-phase polymerized. From the viewpoint of improving the wear resistance, it is preferable to have a crystallinity, that is, a low ΔHm ₁ .

In order to achieve such a fiber structure, for example, the liquid crystal polyester fiber solid-phase polymerized as described above can be realized by heat-treating the liquid crystal polyester fiber at Tm ₁ + 10 ° C. or higher.

In addition, Tm _{1 of} the above-mentioned liquid crystalline polyester fiber, the peak half width at Tm _{1 and} the heat of fusion ΔHm ₁ indicate values obtained by the method described in the examples.

  The fibers of the present invention preferably have a finishing oil attached to improve wear resistance and process passability by improving the surface smoothness, and the oil adhesion rate of the finishing oil is 0.1 weight relative to the fiber weight. % Is preferred. The oil adhesion rate in the present invention refers to a value obtained by the method described in the examples. Since the effect increases as the amount of oil increases, 0.5% by weight or more is more preferable. However, if the oil content is too much, the adhesive strength between the fibers is increased, the process passability is hindered, and process stains are generated, so 3.0% by weight or less and 2.0% by weight or less are preferable.

  The liquid crystal polyester fiber obtained by the production method of the present invention has high strength, high elastic modulus, less fusion between fibers, and less residue of solid-phase polymerization oil, so that surface irregularities are formed and higher order. It is excellent in process passability in the processing process, and further excellent in adhesion with resin and the like.

  For this reason, it is widely used in the fields of general industrial materials, civil engineering / building materials, sports applications, protective clothing, reinforcing materials, electrical materials (particularly as tension members), acoustic materials, and general clothing. 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 in automobiles and aircraft, power transmission cords for electrical products and robots, etc. It can be most suitably used as a printing screen wrinkle or a mesh fabric for a filter that requires suppression of fluctuations in tension due to generation of deposits in the process in order to improve materials, weaving properties, and fabric quality.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, each characteristic value in an Example was calculated | required with the following method.

A. Single fiber fineness 10 m of fiber was removed with a measuring instrument, the weight (g) was multiplied by 1000, 10 measurements were performed per level, 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).

B. Strength, elongation, elastic modulus 10 measurements per standard using Tensilon UCT-100 manufactured by Orientec under the conditions of sample length 100 mm and tensile speed 50 mm / min according to the method described in JIS L1013: 1999 The average value was defined as strength (cN), strength (cN / dtex), elongation (%), and elastic modulus (cN / dtex). The elastic modulus is the initial tensile resistance.

C. The fiber adhesion rate 100 ± 10 mg of fiber was collected and weighed after drying for 10 minutes at 60 ° C. (W ₀ ), and fiber weight of sodium dodecylbenzenesulfonate in 100 times or more of the fiber weight The fiber was immersed in a solution added at 2.0% by weight, and subjected to ultrasonic cleaning at room temperature for 20 minutes, and the washed fiber was washed with water and dried at 60 ° C. for 10 minutes (W ₁ ). The oil adhesion rate was calculated by the following formula.

(Oil content adhesion rate (% by weight)) = (W ₀ −W ₁ ) × 100 / W ₁
D. Peak half width at _Tm 1, Tm ₁ of the liquid crystal polyester fiber, heat of fusion .DELTA.Hm _1, performs a differential calorimetry by melting TA instruments Co. DSC2920 liquid crystal polyester polymer, was measured at a Atsushi Nobori condition of 20 ° C. / min from 50 ° C. The temperature of the endothermic peak observed at this time was defined as Tm ₁ (° C.), and the peak half-value width (° C.) and heat of fusion (ΔHm ₁ ) (J / g) at Tm ₁ were measured.

Incidentally, after observing the Tm ₁ for a liquid crystal polyester polymer shown in Reference Examples, it was held 5 minutes at a temperature of Tm 1 + ₂₀ ° C., once cooled to 50 ° C. at a cooling condition of 20 ° C. / min, again 20 ° C. / The endothermic peak observed when measured under the temperature rise condition for 2 minutes was defined as Tm _2, and Tm ₂ was defined as the melting point of the polymer.

E. Polystyrene equivalent weight average molecular weight (molecular weight)
A mixed solvent of pentafluorophenol / chloroform = 35/65 (weight ratio) was used as a solvent, and the solution was dissolved so that the concentration of 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 by polystyrene conversion.
Column: Two Shodex K-806M, one K-802 Detector: Differential refractive index detector RI
Temperature: 23 ± 2 ° C
Flow rate: 0.8 mL / min Injection volume: 200 μL
F. Median diameter (D50)
The particle size was measured with a Shimadzu laser diffraction particle size distribution analyzer SALD-2000J, and the median diameter (D50) was determined.

G. Morphological Observation of Fiber Surface Using a scanning electron microscope ESEM-2700 manufactured by Nikon Corporation, morphological observation was performed in the longitudinal direction for all the fibers on a total of 20 fiber surfaces with a length of 5 mm at an acceleration voltage of 15 kV and 1000 times. The surface of the yarn is observed over the entire area of 5 mm in the length of the sampled yarn, and when the number of yarns having irregularities on the surface of the yarn over the entire area of the sampled length of 5 mm is 10 or more, it is determined that there is unevenness, When the number of irregularities was 9 or less, it was determined that there were no irregularities. In addition, when there is a portion where there is no unevenness in the sampled length of 5 mm, if the maximum length of the portion where there is no unevenness does not continuously exceed 1 mm, the entire sampled length of 5 mm Including the number of yarns with unevenness on the surface of the yarn, the length of the portion with no unevenness exceeding 1 mm was excluded from the number.
In addition, when the object was 20 filaments or more, sampling was arbitrarily selected from 20 different filaments, and the sampling was performed so as to have a length of 5 mm. When the number of filaments is 20 or less, 20 pieces are arbitrarily selected from the fibers collected by sampling so that the length is 5 mm every 5 m in the fiber axis direction by the number obtained by adding 1 to the quotient obtained by dividing 20 by the number of filaments. Selected.
H. Fusing suppression effect The package after solid-phase polymerization is fitted into a free-roll creel (having a shaft and bearings, the outer layer can rotate freely. There is no brake and drive source), and the yarn is transverse (fiber circulation direction) from here The surface of the solid-phase polymerization package after being unwound at 400 m / min for 30 minutes was observed, and the fusing suppression effect was evaluated according to the following criteria based on the presence or absence of fluff.

  A: No fluff is seen.

  ○: 1 to 2 fluffs are observed.

  X: 3 or more fluffs are seen.

I. Amount of scum The liquid crystal polyester fiber washer washer tensor Y-601L manufactured by Yuasa Yidomichi Co., Ltd., and the dial scale was set to 0 (At this time, the fiber was allowed to run outside one of the two pipe guides. , Insert two washers (TW-3) into the running pipe guide, and let the fiber run between them (the angle formed by the running yarn is about 90 °). And the weight of the washer before and after running the fiber was measured with an analytical electronic balance (EP214C) manufactured by METTLER TOLEDO, Inc. The fiber length to run is 25,000 m. When the fiber length is less than 100,000 m, the scum generation amount corresponding to the fiber length of 100,000 m was proportionally calculated from the traveled fiber length.

Scum generation amount (g) = (Washer weight after running fiber) − (Washer weight before running fiber)
J. et al. Process passability, weavability, and fabric characteristics (textile quality) evaluation Using a 13 dtex polyester monofilament for warp with a rapier weaving machine, weaving density and weft of 250 / inch (2.54 cm), and driving speed of 100 The test weaving was performed by setting the weft yarn to liquid crystal polyester fiber at a turn / min. At this time, the process passability is evaluated from the accumulation of scum on the yarn feeder (ceramic guide) in the trial weaving with a width of 180 cm and a length of 10 m, and the weaving property is evaluated from the number of stops due to yarn breakage. The quality of the fabric was evaluated from the number of scum. The criteria for each are described below. When the number of stops exceeded 15 times, weaving evaluation was interrupted by determining that weaving was impossible.
<Process passability>
A: Scum accumulation is not observed visually even after weaving. ; Excellent ○: Scum is recognized after weaving, but there is no hindrance to fiber running. Good: scum is observed during weaving and fiber running is hindered.
<Weaving properties>
◎: Stopping 5 times or less; Excellent ○: Stopping 6 to 10 times; Good ×: Stopping 11 times or more; Defect <Textile quality>
A: Number of mixed scum of 5 or less; Excellent ○: 6 to 10; Good ×: 11 or more; Resin adhesiveness After weaving a 250 mesh fabric using liquid crystalline polyester fiber, the resulting fabric was coated with a urethane resin to a thickness of 0.5 mm. After drying at 150 ° C., a reciprocal bending test was performed using a MIT type tester by a method according to JIS P8115. The bending part was observed with the microscope after the bending test, and adhesiveness was evaluated according to the following criteria from the presence or absence of peeling.

◎: No peeling even when the number of folding times is 5000; Excellent ○: Peeling when the number of folding times is 3000 or more and less than 5000; Good Δ: Peeling when the number of folding times is 1000 or more and less than 3000 times; Slightly good ×: Number of folding times 500 times Less than 1000 times and peeling; somewhat poor XX: Folding less than 500 times and peeling; poor Reference Example 1
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 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, 1460 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 335 degreeC in 4 hours.

  The polymerization temperature was maintained at 335 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 40 minutes. When the torque reached 28 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 composition, melting point and molecular weight of the obtained liquid crystal polyester are as shown in Table 1.

Example 1
After vacuum drying at 160 ° C. for 12 hours using the liquid crystal polyester of Reference Example 1, melt extrusion with a φ15 mm single screw extruder manufactured by Osaka Seiki Machine Co., Ltd., and supplying the polymer to the spinning pack while measuring with a gear pump did. In the spinning pack, the polymer was filtered using a metal nonwoven fabric filter, and the polymer was discharged from a 10-hole die. The discharged polymer is allowed to pass through a heat-retaining region of 40 mm, and then cooled and solidified from the outside of the yarn with an annular cooling air flow at 25 ° C., and then a spinning oil mainly composed of a fatty acid ester compound is applied to the polymer. The filament was taken up on the first godet roll. After passing this through the second godet roll at the same speed, all but one of the filaments is sucked with a suction gun, and the remaining one filament fiber is passed through a dancer arm through a pan winder (EFT take by Kozu Seisakusho). It was wound up in the shape of a pan with an upwinder and no contact roll in contact with the winding package. During winding, yarn breakage did not occur, and the yarn forming property was good. The obtained fiber had a fineness of 6.0 dtex, a strength of 6.4 cN / dtex, an elongation of 1.4%, and an elastic modulus of 495 cN / dtex.

The spun fiber package was rewound using an SSP-MV type rewinder (contact length (winding stroke of the innermost layer) 200 mm, wind number 8.7, taper angle 45 °) manufactured by Kozu Seisakusho. The spinning fiber is unwound in the longitudinal direction (perpendicular to the fiber circulation direction), without using a speed control roller, but using an oiling roller (satin-finished stainless steel roll) as a phosphate compound (B) Talc having a median diameter of 1.0 μm shown as talc 1 in Table 2 as inorganic particles (A) in an aqueous solution containing 12.0% by weight of the phosphoric acid compound (B ₁ ) represented by (4), SG-2000 (Japan) The solid phase polymerization oil agent in which 1.0% by weight of Talc Co., Ltd. was dispersed was supplied.

As the core material for rewinding, a bobbin made of stainless steel wound with Kevlar felt (weight per unit area 280 g / m ² , thickness 1.5 mm) was used, and the surface pressure was 100 gf. The oil adhesion rate (a + b) of the solid phase polymerization oil to the fiber after rewinding was 43.3% by weight.

  Next, the bobbin made of stainless steel was removed from the wound package, and solid state polymerization was performed in a package state in which the fiber was wound around Kevlar felt. In solid-phase polymerization, using a closed oven, the temperature is raised from room temperature to 240 ° C. in about 30 minutes, held at 240 ° C. for 3 hours, then heated to 290 ° C. at 4 ° C./hour and held for 20 hours. Solid-state polymerization was performed under the following conditions. The atmosphere was supplied with dehumidified nitrogen at a flow rate of 20 NL / min and exhausted from the exhaust port so that the interior was not pressurized.

The resulting fiber after solid phase polymerization has a fineness of 6.0 dtex, a strength of 22.3 cN / dtex, an elongation of 2.4%, and an elastic modulus of 1079 cN / dtex, compared to the fiber before solid phase polymerization. It was confirmed that the strength, elongation, and elastic modulus were improved and solid phase polymerization was progressing. Incidentally, Tm ₁ is 346 ° C. The resulting fibers, .DELTA.Hm ₁ is peak half width at 7.9J / g, Tm ₁ was 6.1 ° C..

  Fibers were unwound from the thus-obtained package after solid-phase polymerization, and washed to remove the solid-phase polymerization oil agent.

  That is, the package after solid-phase polymerization is fitted into a freeroll creel (having a shaft and a bearing, and the outer layer portion can freely rotate. There is no brake and drive source), and the yarn is pulled out in the lateral direction (fiber circulation direction) from here. Continuously, the fiber was passed through a 150 cm bath (contact length 150 cm) bath (no guide contacting the fiber inside) with slits at both ends, and the oil agent was washed away. The cleaning liquid is 50 ° C. warm water containing 0.2% by weight of nonionic / anionic surfactant (Granup US-30 manufactured by Sanyo Kasei Co., Ltd.). Supplied to. When supplying to the water tank, a pipe having holes formed at intervals of 5 cm was passed through the water tank, and a liquid flow was given to the water tank by supplying the pipe. A cleaning liquid overflowing from the slit and the liquid level adjusting hole is collected and returned to the external tank.

  The washed fiber was then passed through a bath with a bath length of 23 cm (contact length: 23 cm) with slits at both ends (without a guide contacting the fiber inside) and rinsed with hot water at 50 ° C. The fiber after the rinsing was passed through a bearing roller guide, blown away with air flow, and then passed through a first roller with a separation roller of 400 m / min. In addition, since a creel is a free roll, by applying tension | tensile_strength to a fiber with this roller, the unwinding from a solid-phase polymerization package will be performed and a fiber will run.

The fiber that passed through the roller was run between slit heaters having a length of 1 m in which the fibers were heated to 510 ° C., and high-temperature non-contact heat treatment was performed. No guides are provided in the slit heater, and the heater and fiber are not in contact with each other. The fiber after passing through the heater was passed through a second roller with a separate roller. The first roller and the second roller were at the same speed. The fiber that passed through the second roller was provided with a finishing oil mainly composed of a fatty acid ester compound by a ceramic oiling roller, and wound with an EFT type bobbin traverse winder (manufactured by Kozu Seisakusho). The fiber obtained by this high-temperature non-contact heat treatment has a strength of 17.9 cN / dtex and an elastic modulus of 753 cN / dtex, which are lower than those after solid-phase polymerization, but Tm ₁ is 334 ° C. and ΔHm ₁ is 0.00. The peak half-value width at 5 J / g and Tm ₁ is 31 ° C., which is a decrease in crystallinity, and an improvement in wear resistance is expected.

  As shown in Table 2, the physical properties of the obtained fiber were such that the residual solid-phase polymerization oil agent had a very low oil adhesion rate, suppressed scum generation, and had excellent process passability, fabric quality, and weaving properties.

  Formation of uniform unevenness along the longitudinal direction of the fiber could be confirmed, and as a result of the adhesion test, no peeling was observed even after the folding was repeated 5000 times, and the adhesion with the resin was excellent.

  From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

Examples 2-9
A liquid crystal polyester fiber was obtained in the same manner as in Example 1, except that the number of rotations of the oiling roller during rewinding was changed and the oil adhesion rate (a + b) of the solid phase polymerization oil to the fiber after rewinding was changed as shown in Table 2. .

As shown in Table 2, the physical properties of the obtained fibers were extremely low in the oil content adhesion rate of the remaining solid-phase polymerization oil agent, suppressed scum generation, and excellent in process passability, fabric quality, and weaving properties. . Due to the formation of irregularities on the fiber surface, the adhesion was slightly good in Example 2, good in Examples 3 and 4, and Examples 5 to 9 were all excellent.
From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.
In Examples 2 to 4, the reason why the comparative adhesiveness slightly decreased in Example 1 was that, from the observation result of the fiber surface form, the number of uneven fibers was decreased compared to Example 1, A part where unevenness is not partially formed in the longitudinal direction is generated, and the contact area with the resin is small in such a part, and it is estimated that the adhesiveness is slightly lowered.

Examples 10-14
A liquid crystal polyester fiber was prepared in the same manner as in Example 1 except that the dispersion amount of the inorganic particles (A) in the solid phase polymerization oil agent was changed and the adhesion rate (a) wt% of the inorganic particles to the fibers was changed as shown in Table 3. Obtained.

  As shown in Table 3, the physical properties of the obtained fibers are extremely low in the oil adhesion rate of the residual solid-phase polymerization oil agent, the occurrence of scum is suppressed, the process passability and the fabric quality are both excellent, and weaving The properties were good for Examples 10 and 14, and good for Examples 12 and 13. In addition, the adhesiveness was excellent due to the formation of irregularities on the fiber surface.

  From the above results, tension fluctuation is small even in high-order processes such as actual weaving, scum generation is suppressed, and there are few defects when mesh fabrics are used for printing screens, filters, etc. You can expect to have. Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

  In addition, in Examples 10 and 14, the reason why the process passability, weaving property, and fabric quality of the Example 1 were slightly lowered is that the amount of inorganic particles (A) added in Example 10 is low, so solid phase polymerization It is presumed that a slight amount of fusion sometimes occurred, resulting in a decrease in fiber properties, leading to yarn breakage during weaving.

Examples 15 and 16
As shown in Table 4, the phosphoric acid compound (B) was changed to the phosphoric acid compound (B ₂ ) represented by the following chemical formula (5) or the phosphoric acid compound (B ₃ ) represented by the following chemical formula (6). Except for the above, liquid crystal polyester fibers were obtained in the same manner as in Example 1.

  As shown in Table 4, since the physical properties of the obtained fibers were extremely low in the oil adhesion rate of the remaining solid-phase polymerization oil agent, scum generation was suppressed, and the process passability and fabric quality were excellent. The weaving property was also excellent. In any case, the adhesion was excellent due to the formation of irregularities on the fiber surface.

From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.
Example 17
As in Example 1, except that talc having a median diameter of 7.0 μm shown as talc 2 in Table 4 and “Microace” (registered trademark) P-2 (manufactured by Nippon Talc Co., Ltd.) were used as the inorganic particles (A). Liquid crystal polyester fiber was obtained.

  As shown in Table 4, the physical properties of the obtained fiber were such that the residual solid-phase polymerization oil agent had an extremely low oil content adhesion rate, so that scum generation and tension fluctuation were suppressed, and the process passability and fabric quality were excellent. The weaving property was good with 6 stops. The adhesiveness was excellent due to the formation of irregularities on the fiber surface.

  From the above results, although there are some concerns about thread breakage even in high-order processes such as actual weaving, the occurrence of scum is suppressed, and there are few drawbacks when making mesh fabrics such as printing screen wrinkles and filters, It can be expected to have good characteristics. Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

  In addition, since the median diameter of the inorganic particles is large as a factor that slightly reduces the weaving property compared with Example 1, a very slight fusion occurred during the solid-phase polymerization of the fibers, resulting in a decrease in fiber properties. It is presumed that this led to thread breakage during weaving.

Example 18
Liquid crystal in the same manner as in Example 1 except that talc having a median diameter of 11 μm shown as talc 3 in Table 4 and “Talcan Powder” (registered trademark) PK-C (manufactured by Hayashi Kasei Co., Ltd.) were used as inorganic particles (A). Polyester fibers were obtained.

  As shown in Table 4, the physical properties of the obtained fibers were such that the residual solid-phase polymerization oil agent had a very low oil adhesion rate, so that the occurrence of scum was suppressed, and the process passability and fabric quality were excellent. In addition, weaving was good with 9 stops. The adhesiveness was excellent due to the formation of irregularities on the fiber surface.

  From the above results, although there are some concerns about thread breakage even in high-order processes such as actual weaving, the occurrence of scum is suppressed, and there are few drawbacks when making mesh fabrics such as printing screen wrinkles and filters, It can be expected to have good characteristics. Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

In addition, as a factor that the weaving property compared with Example 1 and Example 17 slightly decreased, the median diameter of the inorganic particles is large, so the effect of suppressing fusion is slightly inferior, and very slight fusion occurs during solid-phase polymerization of fibers. It is presumed that due to this, the physical properties of the fiber were lowered, and the yarn was easily broken during weaving.
Example 19
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that Silica 310P (manufactured by Fuji Silysia Chemical Ltd.), which is silica, was used as the inorganic particles (A).

  As shown in Table 4, the physical properties of the obtained fibers were such that the residual solid-phase polymerization oil agent had a very low oil adhesion rate, so that the occurrence of scum was suppressed, and the process passability and fabric quality were excellent. The weaving property was also excellent. The adhesiveness was excellent due to the formation of irregularities on the fiber surface.

  From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

Example 20
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that the temperature of the slit heater was not raised and high temperature non-contact heat treatment was not performed.

As shown in Table 4, the physical properties of the obtained fibers were such that the residual solid-phase polymerization oil agent had a very low oil adhesion rate, so that the occurrence of scum was suppressed, and the process passability and fabric quality were excellent. The weaving property was also excellent. The adhesiveness was excellent due to the formation of irregularities on the fiber surface.
From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

Examples 21-23
In the spinning step, liquid crystal polyester fibers were obtained in the same manner as in Example 1 except that the number of filaments was changed as shown in Table 5 and high temperature non-contact heat treatment was not performed.
As shown in Table 5, the physical properties of the obtained fibers are very low in oil adhesion rate of the remaining solid-phase polymerization oil agent, scum generation is suppressed, and the process passability, fabric quality, and weaving properties are all excellent. there were. In any case, the adhesion was excellent due to the formation of irregularities on the fiber surface.
From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . Furthermore, it has high adhesiveness with the matrix and can be expected to have good properties as a reinforcing material.

Comparative Example 1
When the solid phase polymerization was performed in the same manner as in Example 1 except that only the inorganic particles (A) were used as the oil agent for solid phase polymerization and the phosphoric acid compound (B) was not used, the fibers were fused. Since the fibrils occurred frequently at the time of unwinding and the yarn was broken, it was not possible to carry out the washing process and subsequent steps.
Comparative Example 2
Liquid crystal polyester fibers were obtained in the same manner as in Example 1 except that the inorganic particles (A) were not used as the oil agent for solid phase polymerization.

  Fibril generation was observed in the obtained fiber, which is presumed to be caused by fusion between fibers because inorganic particles (A) were not used as the solid phase polymerization oil agent. As shown in Table 6, the physical properties of the obtained fiber have a high oil content adhesion rate of the residual solid phase polymerized oil, so that the amount of scum accumulated on the yarn feeder is large, and many yarn breaks that are considered to be caused by scum and fibrils occur frequently. Therefore, weaving was stopped.

From the above results, a large amount of scum is generated even in high-order processes such as actual weaving, and yarn breakage due to scum and fibrils occurs frequently.
Comparative Example 3
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that a spinning oil mainly composed of polyethylene glycol laurate was used in place of the phosphoric acid compound (B) as an oil for solid phase polymerization.

  As shown in Table 6, the physical properties of the obtained fibers are high in the adhesion rate of the residual solid-phase polymerization oil agent, so that the amount of scum accumulated on the yarn feeder is large, scum is frequently mixed into the product, and the quality of the fabric and adhesion are It was bad. In addition, yarn breakage occurred frequently, which is presumed to be due to fiber fibrillation due to fusion during solid phase polymerization in addition to yarn breakage due to increased tension fluctuation due to scum deposition.

  From the above results, a large amount of scum is generated even in high-order processes such as actual weaving, fluctuations in running tension increase, thread breakage occurs, and mesh fabrics for printing screens and filters are used. In some cases, defects are expected to occur frequently. In addition, due to poor adhesion, it is expected that the properties as a reinforcing material will be insufficient.

Comparative Example 4
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that an oil agent mainly composed of polydimethylsiloxane was used instead of the inorganic particles (A) and the phosphoric acid compound (B) as the oil agent for solid phase polymerization. .

  As shown in Table 6, the physical properties of the obtained fibers are small in the amount of solid-phase polymerization oil remaining in the calculation, but a small amount of scum is accumulated in the yarn feeder during weaving, and scum is mixed into the product that is considered to be caused by this. There has occurred. In addition, thread breakage, which seems to be due to fluctuations in tension, occurred frequently. Unevenness was not recognized on the fiber surface, and the adhesiveness was somewhat poor. In addition, it became clear from the result of IR measurement of the scum component adhering to the yarn feeder at the time of weaving evaluation that the gelated product derived from polydimethylsiloxane was adhering on the fiber. That is, it is presumed that polydimethylsiloxane gels during solid-phase polymerization and remains on the fiber even after the washing step, causing tension fluctuations.

  From the above results, increase in tension fluctuation is promoted in higher-order processes such as actual weaving, etc., in addition to yarn breakage due to tension fluctuation during weaving, tension weaving during weaving and poor weaving due to occurrence of thread breakage, It is expected that scum will be mixed. Moreover, since the adhesiveness is slightly poor, it is expected that the properties as a reinforcing material are slightly insufficient.

Comparative Example 5
Liquid crystal polyester fibers were obtained in the same manner as in Example 1 except that the number of rotations of the oiling roller during rewinding was changed and the oil adhesion rate (a + b) of the solid phase polymerization oil to the fibers after rewinding was changed as shown in Table 6. .

  As shown in Table 6, the physical properties of the obtained fibers were such that the residual solid-phase polymerization oil agent had a very low oil adhesion rate, so that scum generation was suppressed, and the process passability and fabric quality were excellent. The weaving property was also excellent. However, no irregularities were observed on the fiber surface, and the adhesion was somewhat poor. This is presumed to be because the amount of adhesion of the phosphoric acid compound (B) is small, so that unevenness is not formed on the fiber surface in the solid phase polymerization step, and the contact area with the resin is reduced.

  From the above results, the occurrence of scum is suppressed even in high-order processes such as actual weaving, and it can be expected to have good characteristics with few defects when made into mesh fabrics for printing screens and filters. . On the other hand, the adhesion with the matrix is somewhat poor, and it is expected that the properties as a reinforcing material are slightly insufficient.

Comparative Example 6
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that no washing was performed after the solid phase polymerization step.

As shown in Table 6, the physical properties of the obtained fiber were high in the adhesion rate of the residual solid-phase polymerization oil agent, so that the amount of scum accumulated at the yarn feeder was large, scum was frequently mixed into the product, and the fabric quality was poor. . In addition, yarn breakage occurred frequently, which is presumed to be caused by an increase in tension fluctuation due to scum accumulation.
From the above results, a large amount of scum is generated even in high-order processes such as actual weaving, fluctuations in running tension increase, thread breakage occurs, and mesh fabrics for printing screens and filters are used. In some cases, defects are expected to occur frequently. In addition, the adhesiveness is poor due to a large amount of scum, and the properties as a reinforcing material are expected to be insufficient.

Comparative Example 7
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that solid phase polymerization was not performed.

  The physical properties of the obtained fibers are as shown in Table 6 and are not solid-phase polymerized, so there is no fusion between the fibers, but wefting trial weaving frequently causes yarn breaks and weaving cannot be performed. It was. This is presumed to be because the solid phase polymerization was not performed, so that the strength was insufficient and the abrasion resistance in the test fabric could not be withstood.

Claims (2)

In the method for producing liquid crystal polyester fiber, the inorganic compound (A) and the phosphoric acid compound (B) are applied to the yarn obtained by melt spinning the liquid crystalline polyester, followed by solid phase polymerization, and then washed. When the adhesion rate of (B) is (b) wt%,
b ≧ 26
The manufacturing method of the liquid crystalline polyester fiber characterized by satisfy | filling. A liquid crystal polyester fiber obtained by the production method according to claim 1.