JP6040549B2 - Liquid crystal polyester fiber and method for producing the same - Google Patents

Description

  The present invention relates to a liquid crystal polyester fiber having a high strength and a high elastic modulus and excellent in process passability 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. Here, the solid-phase polymerization reaction is generally performed at a high temperature near the melting point, and therefore, the yarns tend to be fused with each other, and solid-phase polymerization is performed for the purpose of preventing deterioration of the physical properties of the yarn due to the fusion and fibrillation. Giving an oil is an important technical point in the production of liquid crystal polyester fibers.

  On the other hand, the solid-phase polymerization oil agent remains on the fiber surface after the solid-phase polymerization, so that it accumulates on a guide, a roller, and a tension applying device in a post-processing step of the fiber, for example, a weaving step, and scraps called scum are generated. Mixing scum into the product may cause product defects or cause thread breakage due to increased tension fluctuations, so washing and removing solid-phase polymerized oil after solid-phase polymerization is also an important technology in the production of liquid crystal polyester fibers. It is a point.

  As the solid-phase polymerization oil agent, a fluorine-based or silicone-based heat-resistant organic compound has been applied so far. For example, it can be easily formed into a water emulsion, easily applied to the fiber surface, and has high heat resistance at high temperatures. The use of polydimethylsiloxane has been proposed (Patent Documents 1 and 2). That is, according to Patent Documents 1 and 2, as a solid phase polymerization oil agent for liquid crystal polyester fiber, polydimethylsiloxane having high heat resistance is given, and after washing and heat treatment after solid phase polymerization, a liquid crystal polyester having a very low oil adhesion amount. I'm getting fiber.

  In addition, a technique using heat-resistant inorganic particles without using an organic compound as a solid-phase polymerization oil agent is also known (Patent Documents 3 and 4).

JP 2010-209495 A (pages 6 and 7) JP 2010-248681 A (page 11) JP 2006-336147 A (page 6) JP2011-168930A (pages 2 and 8)

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

Since the polydimethylsiloxane used in the production methods described in Patent Documents 1 and 2 is gelated by the cross-linking reaction between polydimethylsiloxanes under solid-state polymerization conditions, the gelled product adheres firmly to the fiber surface. It became clear that even if mechanical cleaning such as ultrasonic cleaning was added in addition to cleaning with a surfactant, it remained on the fiber. That is, the oil adhesion amount in the above document is calculated from the weight of the yarn before washing (W ₀ ) and the weight of the yarn after ultrasonic washing (W ₁ ) by the following formula. Although it does not fall off completely, the amount of solid-phase polymerized oil attached is low in the calculation, but it can be seen that the gelled solid-phase polymerized oil that cannot be measured as the amount of oil adhered remains on the fiber. It was.

Oil adhesion amount (wt%) = (W ₀ −W ₁ ) × 100 / W ₁
For this reason, according to the production methods of Patent Documents 1 and 2, a yarn having an extremely low oil adhesion amount is obtained by strengthening washing in the washing step after solid phase polymerization. In the examples, liquid crystal polyester fibers are used as weft yarns. Although a small amount of weaving process has been confirmed to suppress the generation of scum and product contamination, a small amount of scum has been generated. It became clear that the tension fluctuation increased and yarn breakage and scum product mixing occurred.

  Patent Documents 3 and 4 apply a swellable clay mineral that swells and disperses in water and solid-phase polymerizes, so that the solid-phase polymerized oil is removed by immersing the fiber in water after solid-phase polymerization. It is possible to do that. However, when such inorganic particles are dispersed alone or in a normal spinning oil or the like and applied to the fiber, the inorganic particles adhere to the fiber surface after the solid-phase polymerization step, so that the above polydimethylsiloxane example Although the adhesion rate after cleaning is very low, as in the case of, the inorganic particles fall off by rubbing with a guide or tension applying device in the weaving process, causing the occurrence of tension fluctuations and product defects due to product contamination. It was the cause.

  As described above, as a solid phase polymerization oil agent for liquid crystal polyester fiber, a solid phase polymerization oil agent that has both an anti-fusing effect and excellent detergency has not been developed so far. For this reason, liquid crystal polyester fibers that can be used industrially, have excellent scum generation and tension fluctuation in the weaving process, and have excellent process passability and product yield, and their production technologies have not been proposed so far, and their development Was desired.

  An object of the present invention is to provide a liquid crystal polyester fiber having a small amount of deposits (scum) in the weaving process, small fluctuation in running tension, and excellent process passability and product yield in the weaving process, and a method for producing the same, and a mesh fabric. There is.

  In order to solve the above problems, the liquid crystal polyester fiber of the present invention has the following configuration. That is, the liquid crystal polyester fiber has a running tension fluctuation range (R) of 5 cN or less and an oil adhesion rate of 3.0 wt% or less.

  In order to solve the above problems, the method for producing a liquid crystal polyester fiber of the present invention has the following configuration. That is, it is a method for producing liquid crystal polyester fibers in which inorganic particles (A) and a phosphoric acid compound (B) are applied to a yarn obtained by melt spinning a liquid crystal polyester, followed by solid phase polymerization and then washing.

  In order to solve the above problems, the mesh fabric of the present invention has the following configuration. That is, it is a mesh fabric made of the above liquid crystal polyester fiber.

  The liquid crystalline polyester fiber of the present invention preferably has a scum generation amount of 0.01 g or less.

  The liquid crystal polyester fiber of the present invention preferably has a strength of 12.0 cN / dtex or more.

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.

  The liquid crystal polyester fiber of the present invention is preferably a monofilament.

  The liquid crystal polyester fiber of the present invention is preferably composed of a single polymer component.

  In the liquid crystal polyester fiber of the present invention, the liquid crystal polyester is preferably composed of the following structural units (I), (II), (III), (IV), and (V).

In the method for producing a liquid crystal polyester fiber of the present invention, it is preferable to perform a high-temperature heat treatment after the cleaning at a temperature of the endothermic peak temperature (Tm ₁ ) + 10 ° C. of the liquid crystal polyester fiber after the cleaning.

  In the method for producing a liquid crystal polyester fiber of the present invention, the inorganic particles (A) are preferably one or more selected from silica and silicate.

  In the method for producing a liquid crystal polyester fiber of the present invention, the phosphoric acid compound (B) is preferably at least one selected from compounds represented by the following chemical formulas (1) to (3).

  Since the liquid crystalline polyester fiber of the present invention has a small variation in running tension, the yarn breakage caused by the tension variation in higher-order processing of fibers such as knitting and knitting is suppressed, so that the processability is excellent and the weaving density is high. Densification and weaving can be improved. In addition, product defects due to product twitching and scum mixing can be suppressed, and the product yield is improved. Especially for filters and screens that require high mesh fabrics, weaving density is increased (higher mesh), opening area is increased, opening defects are reduced to improve performance. Improved weaving can be achieved.

  The production method of the liquid crystalline polyester fiber according to the present invention has high strength and high elastic modulus, less deposits (scum) in the weaving process, small fluctuation in running tension, and excellent processability. Fibers can be produced that can give liquid crystal polyester fibers with significantly improved rates. In such a production method, the solid phase polymerization oil agent can be easily removed by washing the liquid crystal polyester fiber after the solid phase polymerization. By washing in this way, liquid crystal polyester fibers having significantly improved process stability and product yield in the weaving process as described above can be obtained.

  Hereinafter, the liquid crystal polyester fiber of the present invention will be described 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 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 in order to suppress fluff generation and yarn breakage due to peeling at the polymer interface, the amount added and used together is preferably 50 wt% or less, more preferably 5 wt% or less. Preferably, 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 fiber in the present invention refers to a yarn spun by a normal melt spinning method.

  The liquid crystalline polyester fiber of the present invention is characterized in that the fluctuation range (R) of running tension is 5 cN or less, preferably 4 cN or less. The fluctuation range (R) of the running tension referred to here is A. The value obtained by the method described in the item. The inventors of the present invention focused on fluctuations in tension as a factor that greatly affects process passability and product yield in high-order processes such as weaving of liquid crystal polyester fibers, and as a result of intensive studies, A. It has been found that there is a good correlation between the fluctuation range (R) of the running tension obtained by the method described in the item, the process passability in the high-order processing step such as weaving and the product yield. That is, when the fluctuation range (R) of the running tension satisfies 5 cN or less, fluctuations in tension particularly when a woven fabric is manufactured can be suppressed, and process passability in the weaving process can be significantly improved.

  When the fluctuation range (R) of the running tension exceeds 5 cN, the fluctuation of the running tension is large. Therefore, the looseness due to the tension spots of the liquid crystal polyester fiber in the warping process and the weft driving process during weaving is induced. Deterioration and product defects of the resulting fabric, resulting in a decrease in product yield.

  The fiber of the present invention has an oil adhesion rate of 3.0 wt% or less. The oil adhesion rate here is the total adhesion rate of the remaining solid-phase polymerization oil and finishing oil remaining on the fiber after washing. The value obtained by the method described in the section. By adjusting the oil adhesion rate to 3.0 wt% or less, the fibers are brought together in the post-processing step, and the number of stops for cleaning of the yarn breakage and oil stains resulting from pseudo-adhesion can be reduced and weaving is improved. To do. When the oil adhesion rate exceeds 3.0 wt%, the yarns caused by excessively attached oil agent frequently come into contact with each other, and the excess oil agent falls off due to rubbing in the process, which is not preferable. Further, from the viewpoint of preventing thread breakage and process contamination caused by the oil agent and improving the weaving property, the oil adhesion rate is more preferably 2.0 wt% or less, and most preferably 1.5 wt% or less. Although there is no particular lower limit, the fiber is usually given a finishing oil for the purpose of exhibiting effects such as lubricity in weaving. From the viewpoint of preventing fiber scraping during weaving, the residual solid-phase polymerization oil and finishing oil are used. The lower limit of the oil adhesion rate, which is the total adhesion rate, is usually about 0.5 wt%, more preferably 0.8 wt% or more, although it depends on the type of oil agent.

  The viewpoint that the scum generation amount of the liquid crystal polyester fiber of the present invention is 0.01 g or less suppresses the generation of scum in the weaving process and maintains the process stability, and also suppresses the mixing of scum into the product and improves the product yield. To preferred. More preferably, it is 0.002 g or less. The amount of scum generated here is H. The value obtained by the method described in the item. The lower limit value of the scum generation amount is not particularly limited, but is practically about 0.0001 g from the viewpoint of the balance between labor and effect in cleaning.

  In addition, although the method of making scum generation amount 0.01 g or less is not specifically limited, For example, an inorganic particle (A) and a phosphate compound (B) are apply | coated to liquid crystal polyester fiber as described in the below-mentioned manufacturing method. Thereafter, solid phase polymerization is performed, and the obtained fiber is washed.

  The number of filaments of the fiber of the present invention is preferably 50 or less, more preferably 20 or less, in order to make the fiber product thinner and lighter. In particular, since the monofilament having 1 filament is a field where suppression of scum generation during weaving and running tension stability are strongly desired, the fiber of the present invention can be used particularly preferably.

  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 means B. This is the value obtained by the method described in the section. 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 manufacturing method described later 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 strength is not particularly limited, but the upper limit that can be reached by the manufacturing method described later is about 30.0 cN / dtex. In addition, the intensity | strength said here is C. in an Example. This is the value obtained by the method described in the section.

  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 manufacturing method described later is about 10.0%. In addition, the term “elongation” used herein refers to C.I. This is the value obtained by the method described in the section.

  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 achieved by the manufacturing method described later is about elastic modulus 1500 cN / dtex. The elastic modulus as used in the present invention means C.I. This is the value obtained by the method described in the section.

  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. By reducing ΔHm ₁ to 6.0 J / g or less, the degree of 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. Abrasion resistance is improved. 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, a liquid crystal polyester fiber subjected to solid phase polymerization as described later can be realized by heat-treating the liquid crystal polyester fiber at Tm ₁ + 10 ° C. or higher.

In addition, the peak half-width at Tm ₁ and Tm _{1 and} the heat of fusion ΔHm ₁ of the above-described liquid crystal polyester fiber are the same as those in the examples. It refers to the value obtained by the method described in the item.

  The finished oil is preferably attached to the fiber obtained by the present invention in order to improve the wear resistance by improving the surface smoothness and the process passability, and the oil adhesion rate of the finished oil is 0. 1 wt% or more is preferable. The oil adhesion rate referred to in the present invention refers to D.I. The value obtained by the method described in the section. Since the effect increases as the amount of oil increases, 0.5 wt% or more is more preferable. However, if there is too much oil, the adhesive strength between the fibers will increase, the adjacent yarns will approach each other and pseudo-bonding will cause thread breakage, and excess oil will accumulate on the guide and tension applying device due to rubbing during the process In order to cause process contamination and increase the number of stops for process cleaning and cause problems such as poor weaving, 3.0 wt% or less and 2.0 wt% or less are preferable.

  As the type of finishing oil, a general finishing oil for polyester monofilaments and the like can be applied, but it is preferable that the finishing oil does not contain particulates in order to avoid deterioration in processability due to scum generation in the weaving process.

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

  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 E. The value measured by the method described in the item.

  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. The weight average molecular weight in terms of polystyrene referred to here is the same as that of F. The value measured by the method described in the item.

  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 50 holes or less, and more preferably 20 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.

  In the present invention, 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 components are heated by a mechanism described later in the solid-phase polymerization process. The modification facilitates removal from the fiber in the subsequent washing step. Since the fiber obtained by washing has a small amount of solid-phase polymerization oil residue on the fiber, the occurrence of scum and fluctuation in running tension are suppressed, so that the weaving property is improved.

  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, phyllite, talc, and mica. 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) referred to here is G. The value measured by the method described in the item.

  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. Note that the concentration of the inorganic particles (A) in the diluent is desirably high from the viewpoint of suppressing fusion, and is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, and the upper limit is 10 wt% from the viewpoint of uniform dispersion. % Or less is preferable, and 5 wt% or less is more preferable. 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 wt% or more, more preferably 1.0 wt% or more. In addition, although there is no restriction | limiting in particular as an upper limit of the density | concentration of a phosphoric acid type compound (B), 50 wt% or less is preferable in order to avoid the excessive adhesion by the viscosity increase of a mixed oil agent, and the adhesion spot by the temperature dependence increase of a viscosity, More Preferably it is 30 wt% 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 addition, when the adhesion rate of the inorganic particles (A) to the fiber is (a) wt% and the adhesion rate of the phosphoric acid compound (B) is (b) wt%, it is preferable to satisfy both of the following conditions.
Condition 1. 30 ≧ a + b ≧ 2.0
Condition 2. a ≧ 0.05
Condition 3. b / a ≧ 1
In the above condition 1, since the fusion can be suppressed as the oil component adhesion rate (a + b) of the solid phase polymerization oil increases, 2.0 wt% or more is preferable. On the other hand, if the amount is too large, the sticky handling deteriorates and 30 wt% or less. Is preferred. More preferably, it is 4.0 wt% or more and 20 wt% or less. The oil adhesion rate (a + b) of the solid-phase polymerization oil to the fiber is the same as that of Example D. It refers to the value of the oil adhesion rate obtained by the method described in the section.

  Here, when an oil agent other than the solid phase polymerization oil agent is applied to the fiber before applying the solid phase polymerization oil agent, Example D. The oil adhesion rate D1 was determined by the method described in the paragraph, and Example D. was applied to the fibers after application of the solid-phase polymerization oil. The oil adhesion rate D2 is determined by the method described in the section, and the oil content adhesion rate (a + b) of the solid phase polymerization oil is defined as D2−D1 which is the difference between them.

  Under condition 2, the adhesion rate (a) of the inorganic particles (A) is 0.05 wt% 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 5 wt% or less from the viewpoint of uniform adhesion.

  Formation of condensed salt during solid-phase polymerization of phosphoric acid compound (B) by setting the adhering rate (b) of phosphoric acid compound (B) to be equal to or higher than the adhering rate (a) of inorganic particles (A) under Condition 3 The excellent detergency derived from is more prominent, and is also preferable from the viewpoint of suppressing sticking 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. The Tm ₁ referred to here is generally the melting point of the liquid crystalline polyester fiber. The value calculated | required by the measuring method of item description is pointed out. 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.

  The present invention is characterized by washing after solid phase polymerization. Since the liquid crystalline polyester fiber obtained by the production method of the present invention can be easily removed by washing, the fiber after washing does not have gelled or solid matter derived from organic components on the fiber. The amount of deposits generated during the weaving process is small, and the fluctuation in running tension is greatly improved, so that the process stability and product yield in the weaving process can be greatly improved. That is, the liquid crystal polyester fiber obtained by the production method of the present invention has a significantly improved product yield of the woven fabric due to less deposits (scum) in the weaving process and less fluctuation in running tension and excellent processability. It is suitable as a fiber that can give liquid crystal polyester fiber. As described above, the liquid crystal polyester fiber having a small amount of deposits (scum), small fluctuation in running tension, and excellent processability can be used particularly suitably for mesh fabrics such as filters and screen wrinkles.

  In the present invention, it is preferable to perform washing after solid phase polymerization from the viewpoint of process passability and product yield improvement in the weaving process. 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 wt%, more preferably 0.1 to 0.5 wt% 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 wt% or less, more preferably 1.0 wt% or less, and most preferably 0.5 wt% or less. It should be noted that the adhesion rate of the remaining solid heavy oil agent was determined in Example D. with respect to the fiber wound immediately after the washing step. The value obtained by the method described in the section.

  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 rotating.

  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.

  Moreover, it is preferable to apply a finishing oil from the viewpoint of improving process passability in a subsequent process after washing. 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 wt% or more with respect to the fiber in order to exert effects such as lubricity by the finishing oil, and for the purpose of preventing soiling in the post-processing step due to excessive application. 0% or less is preferable. The oil adhesion rate of the finishing oil referred to here is that of Example D.F. The value 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 determined by the method described in the item.

In addition, when it is particularly 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 basket 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. In addition, Tm ₁ said here is Example E.1. The value calculated | required by the measuring method of description is pointed out. 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.

  Since the liquid crystalline polyester fiber obtained by the production method of the present invention has high strength, high elastic modulus, and high heat resistance, it does not have gelled or solid matter derived from organic components on the fiber. The amount of deposit generated is small, and the running tension fluctuation is greatly improved.

  For this reason, it is widely used in the fields of general industrial materials, civil engineering / building materials, sports applications, protective clothing, rubber 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 for automobiles and aircraft, power transmission cords for electrical products and robots, etc. Monofilaments to be used include printing screens that require high strength, high elastic modulus, finer fineness, and need to suppress fluctuations in tension due to deposits generated in the process to improve weaving and fabric quality. It can be most suitably used as a mesh fabric for bags and filters.

  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. Running tension fluctuation range (R)
Using liquid crystal polyester fiber, Washer Tensor Y-601L made by Yuasa Yarnichi, dial scale is set to 0 (at this time, two pipe guides are arranged so as to be orthogonal to the fiber running direction), two pipe guides The fiber is made to travel outside one of them, and two washers (TW-3) are inserted into the traveling pipe guide so that the fiber travels between them (the angle formed by the traveling yarn is about 90 °). °), traveling at a speed of 30 m / min, and continuously measuring the tension of the running yarn for 10 minutes at a position 5 to 10 cm downstream from the tensor using a P / C compatible tension meter (model: IT-NR) manufactured by Intec Corporation. Then, the data was collected using the attached TensionStar V400 V1.14 with the EEPROM Damping-timer set to 3. The fluctuation range (R) of the running tension was calculated from the maximum value (Fmax) and the minimum value (Fmin) among the continuous data for 10 minutes by the following equation.

(Running tension fluctuation range (R)) = Fmax−Fmin
B. 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).

C. 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.

D. Oil content: 100mg or more of fiber was collected and weighed after drying for 10 minutes at 60 ° C (W0), and sodium dodecylbenzenesulfonate was added to the fiber weight with 100 times or more water. The fiber is immersed in a solution containing 2.0 wt%, ultrasonically washed at room temperature for 20 minutes, the washed fiber is washed with water, and the weight after drying at 60 ° C. for 10 minutes is measured (W1). The oil adhesion rate was calculated by the following formula.

(Oil content rate (wt%)) = (W0−W1) × 100 / W1
E. 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.

F. 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
G. 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.

H. Amount of scum generation Using liquid crystal polyester fiber, Washer Tensor Y-601L manufactured by Yuasa Yidomichi Kogyo Co., Ltd., dial scale set to 0 (at this time, the two pipe guides are arranged so as to be orthogonal to the fiber running direction. ) Run the fiber on the outside of one of the two pipe guides, insert two washers (TW-3) into the running pipe guide, and let the fiber run between them (running) When the yarn is run at a speed of 400 m / min and the weight of the washer before and after running the fiber is measured with an analytical electronic balance (EP214C) manufactured by METTLER TOLEDO The value shown by the following formula. The running fiber length can be selected from 25,000 m to 100,000 m. When the fiber length is less than 100,000 m, the amount of scum generated is equivalent to the running fiber length of 100,000 m. Was proportionally calculated.

Scum generation amount (g) = (Washer weight after running fiber) − (Washer weight before running fiber)
I. Evaluation of weaving properties and fabric characteristics Using polyester monofilament of 13 dtex for warp with rapier loom, weaving density is set to 250 weft / inch (2.54 cm), weaving speed is 100 times / min, weft is liquid crystalline polyester Weaving trials were conducted as fibers. 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 judging that weaving was impossible.
<Process passability>
Even after weaving, no accumulation of scum is observed visually; excellent (◎)
Although scum is observed after weaving, there is no hindrance to fiber running; good (○)
Scum is observed during weaving and fiber running tension increases; (×)
<Weaving properties>
Stopping 5 times or less; Excellent (◎), 6 to 10 times; Good (◯), 11 times or more; Poor (x)
<Textile grade>
Number of mixed scum: 5 or less; Excellent (◎), 6 to 10; Good (◯), 11 or more; Defective (×)
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.

Reference example 2
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 907 parts by weight of p-hydroxybenzoic acid, 457 parts by weight of 6-hydroxy-2-naphthoic acid and 946 parts by weight of acetic anhydride (1. 03 molar equivalents) was charged into a reaction vessel equipped with a stirring blade and a distillation tube, and the temperature was raised from room temperature to 145 ° C. over 30 minutes while stirring in a nitrogen gas atmosphere, followed by reaction at 145 ° C. for 2 hours. Then, it heated up to 325 degreeC in 4 hours.

  The polymerization temperature was maintained at 325 ° C., the pressure was reduced to 133 Pa in 1.5 hours, and the reaction was continued for another 20 minutes. When the predetermined torque was reached, 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 6.0 wt% of the phosphoric acid compound (B ₁ ) represented by (4), SG-2000 (Nippon Talc) The solid-phase polymerization oil agent in which 1.0 wt% 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 15 wt%.

  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 fiber after solid phase polymerization has a fineness of 6.0 dtex, a strength of 24.5 cN / dtex, an elongation of 2.6%, and an elastic modulus of 1100 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.

  Fibers were unwound from the thus obtained package after solid-phase polymerization, and continuously washed for removing the solid-phase polymerization oil agent and subjected to high-temperature non-contact heat treatment.

  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 wt% of a nonionic / anionic surfactant (Granup US-30 manufactured by Sanyo Kasei Co., Ltd.). Supplied. 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, heated to 510 ° C., and subjected to high-temperature heat treatment. 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).

  As shown in Table 2, the physical properties of the obtained fiber are such that the residual solid-phase polymerization oil has a very low oil adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was also excellent.

The obtained fiber had a Tm ₁ of 339 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 31 ° C., and a scum generation amount of 0.0003 g.

  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.

Examples 2-6
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 fiber are such that the residual solid-phase polymerization oil has a very low oil adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was also excellent.

In addition, Tm ₁ of the fiber obtained in Example 2 was 332 ° C., ΔHm ₁ was 0.6 J / g, the peak half width at Tm ₁ was 29 ° C., and the amount of scum generated was 0.0005 g. The fiber obtained in Example 3 had a Tm ₁ of 335 ° C., ΔHm ₁ of 0.7 J / g, a peak half width at Tm ₁ of 28 ° C., and a scum generation amount of 0.0007 g. The fiber obtained in Example 4 had a Tm ₁ of 337 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 26 ° C., and a scum generation amount of 0.0005 g. The fiber obtained in Example 5 had Tm ₁ of 331 ° C., ΔHm ₁ of 0.7 J / g, peak half width at Tm ₁ of 28 ° C., and scum generation amount of 0.0004 g. The fiber obtained in Example 6 had Tm ₁ of 334 ° C., ΔHm ₁ of 0.6 J / g, peak half width at Tm ₁ of 27 ° C., and scum generation amount of 0.0006 g.

  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.

Example 7
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that the number of filaments was 10 in the spinning process.

  As shown in Table 3, the physical properties of the obtained fiber are extremely low in the solid-phase polymerization oil agent, and the running tension fluctuation range (R) is small. The quality and fabric quality were excellent. The weaving property was also excellent.

The fiber obtained in Example 7 had a Tm ₁ of 338 ° C., ΔHm ₁ of 1.3 J / g, a peak half width at Tm ₁ of 25 ° C., and a scum generation amount of 0.0012 g.

  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.

  The fineness of the fiber obtained by spinning is 6.0 dtex, the strength is 6.1 cN / dtex, the elongation is 1.3%, and the elastic modulus is 463 cN / dtex. The fineness of the fiber after solid-phase polymerization is 6.0 dtex, strength is 23.6 cN / dtex, elongation is 2.5%, elastic modulus is 1058 cN / dtex, and the strength, elongation and elastic modulus are improved compared to the fiber before solid phase polymerization. It was confirmed that solid state polymerization was progressing.

Example 8
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 3, the physical properties of the obtained fiber are such that the residual solid-phase polymerization oil has a very low oil content adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was also excellent.

The fiber obtained in Example 8 had a Tm ₁ of 337 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 28 ° C., and a scum generation amount of 0.0010 g.

  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.

Example 9
As in Example 1, except that talc with a median diameter of 7.0 μm, “Microace” (registered trademark) P-2 (manufactured by Nippon Talc Co., Ltd.) shown as talc 2 in Table 3 is used as the inorganic particles (A). Liquid crystal polyester fiber was obtained.

  As shown in Table 3, the physical properties of the obtained fiber are such that the residual solid-phase polymerization oil has a very low oil content adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was good.

In addition, Tm ₁ of the fiber obtained in Example 9 was 334 ° C., ΔHm ₁ was 0.6 J / g, the peak half width at Tm ₁ was 24 ° C., and the amount of scum generated was 0.0010 g.

  From the above results, although there are some concerns about thread breakage even in high-order processes such as actual weaving, the fluctuation in tension is small, scum generation is suppressed, and when mesh fabrics are used for printing screens, filters, etc. There are few defects and it can be expected to have good characteristics.

  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 10
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 3 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 3, the physical properties of the obtained fiber are extremely low in the solid-phase polymerization oil agent, and the running tension fluctuation range (R) is small. The quality and fabric quality were excellent. The weaving property was good.

In addition, Tm ₁ of the fiber obtained in Example 10 was 334 ° C., ΔHm ₁ was 0.7 J / g, the peak half width at Tm ₁ was 28 ° C., and the amount of scum generated was 0.0009 g.

  From the above results, although there are some concerns about thread breakage even in high-order processes such as actual weaving, the fluctuation in tension is small, scum generation is suppressed, and when mesh fabrics are used for printing screens, filters, etc. There are few defects and it can be expected to have good characteristics.

  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.

Examples 11-14
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 4. Obtained.

  As shown in Table 4, the physical properties of the obtained fibers are such that the residual solid phase polymerization oil has a very low oil adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed, and the process passes. The quality and fabric quality were excellent. The weaving property was also excellent or good.

In addition, Tm ₁ of the fiber obtained in Example 11 was 336 ° C., ΔHm ₁ was 0.5 J / g, the peak half width at Tm ₁ was 29 ° C., and the amount of scum generated was 0.0012 g. The fiber obtained in Example 12 had a Tm ₁ of 337 ° C., ΔHm ₁ of 0.7 J / g, a peak half width at Tm ₁ of 27 ° C., and a scum generation amount of 0.0007 g. The fiber obtained in Example 13 had Tm ₁ of 332 ° C., ΔHm ₁ of 0.6 J / g, peak half width at Tm ₁ of 24 ° C., and scum generation amount of 0.0007 g. The fiber obtained in Example 14 had a Tm ₁ of 333 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 26 ° C., and a scum generation amount of 0.0011 g.

  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.

In Example 11, compared with Example 1, the amount of inorganic particles (A) was low as a factor that slightly reduced the weaving property, so that some fusion occurred during solid-phase polymerization, which is attributed to this. Therefore, it is assumed that the physical properties of the fibers were lowered, leading to yarn breakage during weaving.
Further, compared to Example 1 in Example 14, the amount of inorganic particles (A) added as a factor that slightly reduced the weaving occurred, adhesion spots occurred, and some fusion occurred during solid phase polymerization, It is presumed that the fiber physical properties were lowered due to this, 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, the physical properties of the obtained fiber are such that the residual solid phase polymerization oil has a very low oil adhesion rate and has a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was also excellent.

The fiber obtained in Example 15 had a Tm ₁ of 329 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 28 ° C., and a scum generation amount of 0.0006 g. The fiber obtained in Example 16 had a Tm ₁ of 330 ° C., ΔHm ₁ of 0.6 J / g, a peak half width at Tm ₁ of 27 ° C., and a scum generation amount of 0.0007 g.

  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.

Examples 17 and 18
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that the discharge amount in the spinning process was changed and the fineness was changed.

  As shown in Table 5, the physical properties of the obtained fiber have a very low oil adhesion rate of the residual solid-phase polymerization oil agent and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. The weaving property was also excellent.

The fiber obtained in Example 17 had a Tm ₁ of 338 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 29 ° C., and a scum generation amount of 0.0007 g. The fiber obtained in Example 18 had Tm ₁ of 336 ° C., ΔHm ₁ of 0.7 J / g, peak half-width at Tm ₁ of 26 ° C., and scum generation amount of 0.0006 g.

  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.

  The fiber obtained by spinning in Example 17 had a fineness of 4.0 dtex, a strength of 5.8 cN / dtex, an elongation of 1.3%, and an elastic modulus of 460 cN / dtex. The fineness of the fiber is 4.0 dtex, the strength is 21.0 cN / dtex, the elongation is 2.3%, the elastic modulus is 1059 cN / dtex, and the strength, elongation, and elastic modulus are higher than those of the fiber before solid phase polymerization. It was confirmed that solid phase polymerization was progressing.

  Further, the fineness of the fiber obtained by spinning in Example 18 was 13.0 dtex, the strength was 6.1 cN / dtex, the elongation was 1.3%, and the elastic modulus was 484 cN / dtex. The fineness of the fiber is 13.0 dtex, the strength is 20.5 cN / dtex, the elongation is 2.2%, the elastic modulus is 945 cN / dtex, and the strength, elongation, and elastic modulus are higher than those of the fiber before solid phase polymerization. It was confirmed that solid phase polymerization was progressing.

Example 19
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 increased and the high temperature heat treatment was not performed.

  As shown in Table 5, the physical properties of the obtained fiber have a very low oil adhesion rate of the residual solid-phase polymerization oil agent and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. Moreover, the weaving property was also good.

In addition, Tm ₁ of the fiber obtained in Example 19 was 345 ° C., ΔHm ₁ was 7.8 J / g, the peak half-width at Tm ₁ was 6.3 ° C., and the amount of scum generated was 0.0012 g.

  From the above results, there are concerns about slight yarn breakage even in high-order processes such as actual weaving, but the tension fluctuation is small, the occurrence of scum is suppressed, and when mesh fabrics are used for printing screens, filters, etc. Can be expected to have good characteristics with few defects.

  In addition, since heat treatment was not performed as a factor that slightly reduced the weaving property as compared with Example 1, fiber fibrils were likely to be generated by rubbing in the process, which led to yarn breakage during weaving. Infer.

Example 20
A liquid crystal polyester fiber was obtained in the same manner as in Example 19 except that the liquid crystal polyester polymer of Reference Example 2 was used at the time of spinning.

  As shown in Table 5, the physical properties of the obtained fiber have a very low oil adhesion rate of the residual solid-phase polymerization oil agent and a small running tension fluctuation range (R), so that scum generation and tension fluctuation are suppressed. Passability and fabric quality were excellent. Moreover, the weaving property was also good. The fiber before solid phase polymerization obtained by spinning has a fineness of 6.0 dtex, a strength of 8.8 cN / dtex, an elongation of 2.0%, and an elastic modulus of 532 cN / dtex. The strength, elongation, and elastic modulus were improved as compared with the above fiber, and it was confirmed that solid phase polymerization was progressing.

In addition, Tm ₁ of the fiber obtained in Example 20 was 320 ° C., ΔHm ₁ was 11 J / g, the peak half width at Tm ₁ was 7.5 ° C., and the amount of scum generated was 0.0012 g.

  From the above results, there are concerns about slight yarn breakage even in high-order processes such as actual weaving, but the tension fluctuation is small, the occurrence of scum is suppressed, and when mesh fabrics are used for printing screens, filters, etc. Can be expected to have good characteristics with few defects.

  In addition, since heat treatment was not performed as a factor that slightly reduced the weaving property as compared with Example 1, fiber fibrils were likely to be generated by rubbing in the process, which led to yarn breakage during weaving. Infer.

Examples 21-23
Liquid crystal polyester fibers were obtained in the same manner as in Example 1 except that the number of rotations of the oiling roller was changed when the finishing oil was applied, and the oil adhesion rate of the finishing oil was changed.

  As shown in Table 6, the physical properties of the obtained fiber are extremely low in the solid-phase polymerization oil agent, and the running tension fluctuation range (R) is small. The quality and fabric quality were excellent. The weaving property was also excellent or good. As the oil adhesion rate of the finishing oil increased, the frequency of yarn breakage due to the pseudo-adhesion of the fibers increased, and the tendency of the weaving to decrease was confirmed.

In addition, Tm ₁ of the fiber obtained in Example 21 was 338 ° C., ΔHm ₁ was 0.6 J / g, the peak half width at Tm ₁ was 24 ° C., and the amount of scum generated was 0.0007 g. The fiber obtained in Example 22 had a Tm ₁ of 335 ° C., ΔHm ₁ of 0.7 J / g, a peak half width at Tm ₁ of 27 ° C., and a scum generation amount of 0.0007 g. The fiber obtained in Example 23 had a Tm ₁ of 337 ° C., ΔHm ₁ of 0.5 J / g, a peak half width at Tm ₁ of 23 ° C., and a scum generation amount of 0.0009 g.

  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.

Example 24
The liquid crystal polyester of Reference Example 1 and polyether ether ketone resin PEEK90G (melting point: 344 ° C., hereinafter referred to as PEEK) manufactured by Victrex were used. Spinning, rewinding, solid phase polymerization, washing, high-temperature heat treatment in the same manner as in Example 1 except that liquid crystal polyester and PEEK were mixed in a pellet form at a weight ratio of 90/10 and then melted and kneaded with an extruder. The blend fiber which consists of liquid crystalline polyester was obtained.

  As shown in Table 6, although the physical properties of the obtained fibers were slightly reduced in strength and elastic modulus compared to the fibers of Example 1, the oil adhesion rate of the remaining solid-phase polymerization oil agent was extremely low, and the running tension fluctuated. Since the width (R) was small, scum generation and tension fluctuation were suppressed, and the process passability and the fabric quality were excellent. Moreover, the weaving property was also good.

The fiber obtained in Example 24 had a Tm ₁ of 344 ° C., ΔHm ₁ of 4.4 J / g, a peak half width at Tm ₁ of 15.47 ° C., and a scum generation amount of 0.0012 g.

  From the above results, there are concerns about slight yarn breakage even in high-order processes such as actual weaving, but the tension fluctuation is small, the occurrence of scum is suppressed, and when mesh fabrics are used for printing screens, filters, etc. Can be expected to have good characteristics with few defects.

  In addition, as compared with Example 1, as a factor that the weaving property is slightly lowered, because of the blended fibers of different polymers, fiber fibrils are likely to occur due to peeling at the polymer interface due to abrasion in the process. It is estimated that this led to an increase in the number of yarn breaks during weaving.

  The fineness of the fiber obtained by spinning is 6.0 dtex, the strength is 5.6 cN / dtex, the elongation is 1.2%, and the elastic modulus is 432 cN / dtex. The fineness of the fiber after solid-phase polymerization is 6.0 dtex, strength is 22.1 cN / dtex, elongation is 2.3%, elastic modulus is 985 cN / dtex, and the strength, elongation and elastic modulus are improved compared to the fiber before solid phase polymerization. It was confirmed that solid state polymerization was progressing.

Example 25
Spinning in the same manner as in Example 1 except that the liquid crystal polyester of Reference Example 1 was used as the core component, PEEK was used as the sheath polymer, and the liquid crystal polyester and PEEK melted by separate extruders were supplied to the die for the core-sheath composite fiber. Rewinding, solid phase polymerization, washing, and high temperature heat treatment were performed to obtain a composite fiber made of liquid crystal polyester having a core / sheath weight ratio of 70/30.

  As shown in Table 6, although the physical properties of the obtained fibers were slightly reduced in strength and elastic modulus compared to the fibers of Example 1, the oil adhesion rate of the remaining solid-phase polymerization oil agent was extremely low, and the running tension fluctuated. Since the width (R) was small, scum generation and tension fluctuation were suppressed, and the process passability and the fabric quality were excellent. Moreover, the weaving property was also good.

In addition, Tm ₁ of the fiber obtained in Example 25 was 344 ° C., ΔHm ₁ was 13 J / g, the peak half width at Tm ₁ was 16 ° C., and the amount of scum generated was 0.0010 g.

  From the above results, there are concerns about slight yarn breakage even in high-order processes such as actual weaving, but the tension fluctuation is small, the occurrence of scum is suppressed, and when mesh fabrics are used for printing screens, filters, etc. Can be expected to have good characteristics with few defects.

  As compared with Example 1, the reason why the weaving property was slightly lowered was the core-sheath composite fiber with the different polymer, so that fiber fibrils were easily generated due to peeling at the polymer interface due to abrasion in the process. It is presumed that this led to an increase in the number of yarn breaks during weaving.

  The fineness of the fiber obtained by spinning is 6.0 dtex, the strength is 4.9 cN / dtex, the elongation is 1.0%, and the elastic modulus is 343 cN / dtex. The fineness of the fiber after solid-phase polymerization is 6.0 dtex, strength is 16.7 cN / dtex, elongation is 1.7%, elastic modulus is 758 cN / dtex, and the strength, elongation and elastic modulus are improved compared to the fiber before solid phase polymerization. It was confirmed that solid state polymerization was progressing.

Comparative Example 1
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 7, the physical properties of the obtained fiber are high in the oil adhesion rate of the residual solid-phase polymerization oil agent and high in the running tension fluctuation range (R), so the amount of scum accumulated on the yarn feeder is large, and the scum on the product Mixing occurred frequently and the quality of the fabric was poor. In addition, yarn breakage occurred frequently, which is presumed to be caused by an increase in tension fluctuation due to scum accumulation. The amount of scum generated in the fiber obtained in Comparative Example 1 was 0.0636 g.

  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.

Comparative Example 2
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 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 7, the physical properties of the obtained fiber are high in the oil adhesion rate of the residual solid-phase polymerization oil agent and high in the running tension fluctuation range (R), so the amount of scum accumulated on the yarn feeder is large, and the scum on the product Mixing occurred frequently and the quality of the fabric was poor. 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.

In addition, Tm ₁ of the fiber obtained in Comparative Example 3 was 332 ° C., ΔHm ₁ was 0.7 J / g, the peak half width at Tm ₁ was 25 ° C., and the amount of scum generated was 0.0110 g.

  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.

Comparative Example 4
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. In addition, as shown in Table 7, the physical properties of the obtained fibers are high in the adhesion rate of the residual solid-phase polymerization oil agent and the running tension fluctuation range (R) is high, so that the amount of scum accumulated on the yarn feeder is large. Weaving was discontinued due to frequent thread breakage that was probably caused by fibrils.

The fiber obtained in Comparative Example 4 had a Tm ₁ of 335 ° C., ΔHm ₁ of 0.6 J / g, a peak half width at Tm ₁ of 24 ° C., and a scum generation amount of 0.0113 g.

  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 5
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 7, the physical properties of the obtained fibers are small in calculation of the remaining solid-phase polymerization oil agent, but the running tension fluctuation is large, and a small amount of scum is accumulated at the yarn feeder during weaving, which is considered to be caused by this. The running tension increased and scum was mixed into the product. In addition, thread breakage, which seems to be due to fluctuations in tension, occurred frequently. The surface of the liquid crystal polyester fiber also has irregularities that can be seen as a gel of polydimethylsiloxane from the result of scanning electron microscope, and the result of IR measurement of the scum component adhering to the yarn feeder at the time of weaving evaluation also shows polydimethylsiloxane. It was clarified from the fact that the gelled product derived from was attached 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.

The fiber obtained in Comparative Example 5 had a Tm ₁ of 336 ° C., ΔHm ₁ of 0.7 J / g, a peak half-width at Tm ₁ of 27 ° C., and a scum generation amount of 0.0025 g.

  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 and poor weaving due to occurrence of tension spots and thread breakage during weaving, as well as products It is expected that scum will be mixed.

Comparative Example 6
A liquid crystal polyester fiber was obtained in the same manner as in Example 1 except that the oiling roller rotation rate was changed at the time of applying the finishing oil, the oil adhesion rate of the finishing oil was changed, and the fiber oil adhesion rate was 3.2 wt%. It was.

  As shown in Table 7, the physical properties of the obtained fibers are such that the residual solid-phase polymerization oil has a very low oil adhesion rate and a small running tension fluctuation range (R), so that scum generation and tension fluctuations are suppressed. Passability and fabric quality were excellent. However, weaving was stopped because frequent stops due to yarn breakage due to pseudo-bonding of fibers.

The fiber obtained in Comparative Example 6 had a Tm ₁ of 333 ° C., ΔHm ₁ of 0.8 J / g, a peak half width at Tm ₁ of 29 ° C., and a scum generation amount of 0.0012 g.

  From the above results, although the effect of suppressing scum is remarkable even in high-order processes such as actual weaving, the oil adhesion rate is high, so yarn breakage frequently occurs due to pseudo-bonding of fibers, so weaving is impossible Is expected.

Claims (12)

  A liquid crystal polyester fiber having a running tension fluctuation range (R) of 5 cN or less and an oil adhesion rate of 3.0 wt% or less.   The liquid crystal polyester fiber according to claim 1, wherein the amount of scum generated is 0.01 g or less.   The liquid crystal polyester fiber according to claim 1 or 2, wherein the strength is 12.0 cN / dtex or more.   4. The peak half-value width in an endothermic peak (Tm1) observed when the temperature is measured at 50 ° C. to 20 ° C./min in differential calorimetry is 15 ° C. or more. Liquid crystal polyester fiber.   The liquid crystal polyester fiber according to any one of claims 1 to 4, which is a monofilament.   The liquid crystal polyester fiber according to any one of claims 1 to 5, comprising a single polymer component. The liquid crystal polyester fiber according to any one of claims 1 to 6, wherein the liquid crystal polyester comprises the following structural units (I), (II), (III), (IV), and (V).

  A mesh fabric comprising the liquid crystal polyester fiber according to any one of claims 1 to 7.   A method for producing a liquid crystal polyester fiber, characterized in that inorganic yarn (A) and phosphoric acid compound (B) are applied to a yarn obtained by melt spinning liquid crystal polyester, followed by solid phase polymerization and then washing .   The method for producing a liquid crystal polyester fiber according to claim 9, wherein the liquid crystal polyester fiber is subjected to a high temperature heat treatment after the cleaning at a temperature of the endothermic peak temperature (Tm1) + 10 ° C or higher after the cleaning.   The method according to claim 9 or 10, wherein the inorganic particles (A) are at least one selected from silica and silicate. The production method according to any one of claims 9 to 11, wherein the phosphoric acid compound (B) is at least one selected from compounds represented by the following chemical formulas (1) to (3).