JP2011058122A - Polyester textured yarn - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester textured yarn which is suitable for reinforcement whose strength and adhesion are both established. <P>SOLUTION: A polyester textured yarn, having fluff consisting of polyethylene naphthalate fiber on the surface, is characterized in that a crystal volume obtained by the X-ray wide angle diffraction of the polyethylene naphthalate fiber is ranging from 550 to 1,200 nm<SP>3</SP>, and in that crystallinity is ranging from 30 to 60%. Also, it is desired that the textured yarn is spun yarn, and that the polyethylene naphthalate fiber contains phosphorus atom by 0.1 to 300 mmol% with respect to an ethylene naphthalate unit, and that the phosphorus atom is originated from phenyl phosphinic acid or phenylphosphonic acid, and that the polyethylene naphthalate fiber contains metallic elements. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester processed yarn, and more particularly to a polyester processed yarn suitable for reinforcing industrial materials made of polyethylene naphthalate fibers.

  Among the general-purpose polyester fibers, polyethylene naphthalate fibers exhibit high strength, high modulus and excellent dimensional stability, and are processed for industrial materials such as rubber cords such as tire cords and transmission belts. Widely used as a thread. For example, Patent Document 1 discloses that a polyethylene naphthalate short fiber having a uniform fiber cross-sectional diameter is used as a spun yarn and used as a reinforcing fiber. However, the spun yarn has fluff and increased adhesion, but has a problem that the fiber strength is inevitably inferior to that of the long fiber filament yarn which is a normal reinforcing fiber.

On the other hand, as one means for improving the physical properties of such polyester processed yarn, there is a method of improving the physical properties of polyethylene naphthalate fiber itself used for the processed yarn. For example, Patent Document 2 proposes a polyethylene naphthalate fiber having excellent heat resistance by performing high-speed spinning. However, when the melting point is high, the strength is low, and when the strength is high, the melting point is low. The strength and heat resistance could not be satisfied at a high level. Also, for example, in Patent Document 3, a heated spinning cylinder heated to 390 ° C. is installed directly under the melt spinning base, and a high-speed polyethylene naphthalate having excellent strength is obtained by performing high-speed spinning of a draft of about 300 times and hot drawing. A fiber is disclosed. However, the melting point of the obtained fiber was still as low as 288 ° C., the strength was insufficient at 8.0 g / de (about 6.8 N / dtex), and the heat resistance was not yet satisfactory. In addition, Patent Document 4 and Patent Document 5 propose polyethylene naphthalate fibers having high strength and excellent thermal stability by optimizing spinning conditions and the like. However, by any of these methods, although the physical strength of the obtained fiber is high, its melting point is as low as 284 ° C. or less, and the polyethylene naphthalate fiber having a satisfactory level of heat resistance is Not obtained.
That is, when a conventionally known polyethylene naphthalate fiber is used, a polyester processed yarn satisfying sufficient adhesiveness and strength, particularly heat resistance, has not yet been obtained.

JP 2008-057090 A Japanese Patent Laid-Open No. 62-155631 Japanese Patent Laid-Open No. 06-184815 Japanese Patent Laid-Open No. 04-352811 JP 2002-339161 A

  An object of the present invention is to provide a polyester processed yarn that has both strength and adhesiveness and is suitable for reinforcement.

The polyester processed yarn of the present invention is a polyester processed yarn having fluffs made of polyethylene naphthalate fiber on the surface, the crystal volume obtained from X-ray wide angle diffraction of the polyethylene naphthalate fiber is 550 to 1200 nm ³ , and The crystallinity is 30 to 60%.

Further, the polyester processed yarn is a check yarn, the polyethylene naphthalate fiber contains a phosphorus atom in an amount of 0.1 to 300 mmol% with respect to an ethylene naphthalate unit, the polyethylene naphthalate fiber The phosphorus atom is preferably derived from phenylphosphinic acid or phenylphosphonic acid, and the polyethylene naphthalate fiber preferably contains a metal element.
Another fiber polymer composite of the present invention is a fiber polymer composite reinforced with the above-described polyester processed yarn of the present invention.

  According to the present invention, a polyester processed yarn having both strength and adhesiveness and suitable for reinforcement is provided.

It is an example of a check-up processing apparatus.

  The polyester processed yarn of the present invention has fluff made of polyethylene naphthalate fiber on the surface. The fiber having such fluff may be a spun yarn made of short fibers, but in order to fully exhibit the strength of the fibers, a check yarn obtained by processing long fibers is preferable.

  The total fineness of the polyester processed yarn of the present invention is preferably in the range of 50 to 5000 dtex, and more preferably in the range of 200 to 3000 dtex. And although the polyester processed thread | yarn of this invention has a fluff, it is preferable that the fineness of the single yarn which comprises the fluff is 1 dtex or more and 7 dtex or less. Furthermore, it is a range of 1 dtex or more and 5 dtex or less, and most preferably 1 dtex or more and 3 dtex or less. When the single yarn fineness is too thin, the strength of the fluff is lowered, and it tends to be difficult to use for reinforcing applications required for industrial materials. On the other hand, when the single yarn fineness is large, the number of single yarns in the processed yarn filament is reduced, and the entanglement of the yarn is reduced. For this reason, not only does the final processed yarn tend to have low strength, but also the process passability during production tends to decrease. In particular, in the case of a check yarn, a high tension is applied to the yarn as compared with the spun yarn, and therefore entanglement during the process is particularly important. As a balance between the single yarn fineness and the total fineness of the filament, the number of filament yarns forming the processed yarn is preferably 50 or more and 1000 or less. When the number of constituents decreases, each single yarn fineness increases. Conversely, when the number of constituents is too large, each single yarn fineness becomes too small.

  Moreover, it is also preferable that such a polyester processed yarn of the present invention is obtained by combining a plurality of yarns. The fineness of the yarn before the combined yarn is preferably 400 to 700 dtex. Furthermore, it is preferable that the yarn is twisted when the yarns are combined. By performing twisting, the single yarn strength can be effectively utilized, and finally the strength of the polyester processed yarn can be effectively increased.

  The polyester processed yarn of the present invention is made of polyethylene naphthalate fiber. The polyethylene naphthalate fiber may be a fiber whose main repeating unit is ethylene naphthalate, but ethylene-2, Polyethylene naphthalate fibers containing 6-naphthalate units of 80% or more, particularly 90% or more are preferred. If it is a small amount, it may be a copolymer containing an appropriate third component.

  In the polyethylene naphthalate, various additives such as matting agents such as titanium dioxide, heat stabilizers, antifoaming agents, color modifiers, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers. Additives such as montmorillonite, bentonite, hectorite, plate-like iron oxide, plate-like calcium carbonate, plate-like boehmite, or carbon nanotubes as additives for fluorescent brighteners, plasticizers, impact agents, or reinforcing agents It may be.

The polyethylene naphthalate fiber used in the present invention is a fiber made of polyethylene naphthalate as described above, and further has a crystal volume of 550 to 1200 nm ³ obtained by X-ray wide-angle diffraction and a crystallinity of 30 to It is essential to be 60%. Furthermore, the crystal volume is preferably 600 to 1000 nm ³ . The crystallinity is preferably 35 to 55%.

  Here, the crystal volume of the fiber is a product of crystal sizes obtained from diffraction peaks having diffraction angles of 15 to 16 degrees, 23 to 25 degrees, and 25.5 to 27 degrees in the wide-angle X-ray diffraction of the fibers. Incidentally, each of these diffraction angles is due to surface reflection at the crystal planes (010), (100), and (1-10) of the polyethylene naphthalate fiber, and theoretically corresponds to each Bragg reflection angle 2θ. However, it has a peak slightly shifted due to a change in the entire crystal structure. Moreover, such a crystal structure is peculiar to polyethylene naphthalate fiber. For example, even if it is the same polyester fiber, it does not exist in polyethylene terephthalate fiber.

The crystallinity (Xc) of the fiber is a value obtained by the following (Equation 1) from the specific gravity (ρ), the complete amorphous density (ρa) and the complete crystal density (ρc) of polyethylene naphthalate. .
Crystallinity Xc = {ρc (ρ−ρa) / ρ (ρc−ρa)} × 100 (Equation 1)
In the formula
ρ: Specific gravity of polyethylene naphthalate fiber ρa: 1.325 (fully amorphous density of polyethylene naphthalate)
ρc: 1.407 (complete crystal density of polyethylene naphthalate).

This polyethylene naphthalate fiber used in the present invention achieves high thermal stability and a high melting point by maintaining a high crystallinity similar to that of conventional high-strength fibers while achieving a high crystal volume that has never existed before. The feature is that it was able to be obtained. When the crystal volume is less than 550 nm ³ (550,000 angstrom ³ ), such a high melting point cannot be obtained. The higher the crystal volume, the better the thermal stability and the better. However, in this case, since the crystallinity tends to decrease and the strength tends to decrease, the upper limit is 1200 nm ³ (1.2 million angstrom ³ ) in the present invention. . On the other hand, if the degree of crystallinity is less than 30%, the amorphous portion is liable to undergo thermal deterioration and sufficient heat resistance cannot be ensured.

  In order to increase the fiber crystal volume in this way, a method of spinning while keeping the temperature below the die during spinning is effective. A large crystal volume can also be obtained by increasing the spinning draft ratio, the draw ratio, etc., and stretching the fiber. However, if the spinning draft ratio is increased, the polyethylene naphthalate fiber, which is a rigid fiber, is likely to be broken, and it is particularly effective to keep the spinning draft ratio at about 100 to 5000 and increase the draw ratio. Normally, when drafting is performed to increase the crystal volume while keeping the temperature below the die at the time of spinning, yarn breakage occurs during spinning, making it difficult to produce fibers. The polyethylene naphthalate fiber used in the present invention can realize such a crystal volume by using a specific phosphorus compound described later.

In order to increase the degree of crystallinity of the fiber, it can be obtained by increasing the spinning draft ratio, the draw ratio, etc., and stretching the fiber at a high ratio, as in the case of increasing the crystal volume. However, as the crystal volume increases and the degree of crystallinity increases, the polyethylene naphthalate fiber, which is a rigid fiber, is more likely to break. Therefore, in the polyethylene naphthalate fiber used in the present invention, the crystal volume, which is a contradictory property, is within the range of 550 to 1200 nm ³ and the degree of crystallinity is 30 to 60%. It is important to form a uniform crystal structure. For example, such a uniform crystal structure can be realized by including a specific phosphorus compound described later in the polymer.

  Further, the polyethylene naphthalate fiber used in the present invention preferably has a maximum peak diffraction angle of X-ray wide angle diffraction in the range of 25.5 to 27.0 degrees. The reason is not clear, but among the (010), (100), and (1-10) crystal planes, the (1-10) plane crystal grows greatly on the fiber axis, resulting in greatly improved heat resistance. To be improved. The size of the crystal parallel to the fiber axis can be increased by stretching the fiber in a certain direction at a high magnification, for example, by increasing the spinning draft ratio, the draw ratio, and the like.

  The polyethylene naphthalate fiber used in the present invention preferably contains 0.1 to 300 mmol% of phosphorus atoms with respect to the ethylene naphthalate unit. Furthermore, the phosphorus atom content is preferably 10 to 200 mmol%. This is because it becomes easy to control crystallinity by the phosphorus compound. On the other hand, when the amount is too large, foreign matter defects are generated during spinning, so that the spinning property is lowered and the physical properties tend to be lowered.

  In addition, the polyethylene naphthalate fiber usually contains a metal element as a catalyst, but in the present invention, it preferably contains a metal element, and more preferably a divalent metal. Moreover, it is preferable that the metal element contained in this fiber is at least one or more metal elements selected from the group consisting of metal elements of Group 4 to Group 5 and Group 12 and Period 4 and Mg in the periodic table. In particular, the metal element contained in the fiber is preferably at least one metal element selected from the group consisting of Zn, Mn, Co, and Mg. The reason is not clear, but when these metal elements are used in combination with a phosphorus compound, a uniform crystal with little variation in crystal volume is easily obtained.

  As content of such a metal element, it is preferable to contain 10-1000 mmol% with respect to an ethylene naphthalate unit. The P / M ratio, which is the abundance ratio of the phosphorus element P and the metal element M, is preferably in the range of 0.8 to 2.0. When the P / M ratio is too small, the metal concentration becomes excessive, and the excess metal component tends to accelerate the thermal decomposition of the polymer and impair the thermal stability. On the other hand, when the P / M ratio is too large, the phosphorus compound is excessive, so that the polymerization reaction of the polyethylene naphthalate polymer is inhibited and the fiber physical properties tend to be lowered. A more preferable P / M ratio is preferably 0.9 to 1.8.

  The strength of the polyethylene naphthalate fiber used in the present invention is preferably 4.0 to 10.0 cN / dtex. Furthermore, it is preferably 5.0 to 9.0 cN / dtex, more preferably 6.0 to 8.0 cN / dtex. When the strength is too low, the durability tends to be inferior when the strength is too high. In addition, when production is performed with a very high strength, yarn breakage tends to occur in the yarn making process, and there is a tendency for quality stability as an industrial fiber.

  The melting point of the fiber is preferably 285 to 315 ° C. Furthermore, it is optimal that it is 290-310 degreeC. When the melting point is too low, heat resistance and dimensional stability tend to be inferior. On the other hand, if it is too high, melt spinning tends to be difficult. When the fiber has a high melting point, the heat resistance and strength maintenance rate of the fiber can be kept high, which is optimal as a reinforcing fiber for a composite material used in a high temperature atmosphere.

  The dry heat shrinkage at 180 ° C. is preferably 0.5 to less than 4.0%. Furthermore, it is preferable that it is 1.0 to 3.5%. If the dry heat shrinkage is too high, the dimensional change during processing tends to be large, and the dimensional stability of a molded product using fibers tends to be poor. Such a high melting point and a low dry heat shrinkage rate are achieved by increasing the crystal volume of the polymer constituting the fiber of the present invention.

  Moreover, it is preferable that the peak temperature of tan-delta of the polyethylene naphthalate fiber used by this invention is 150-170 degreeC. The tan δ of the conventional polyethylene naphthalate fiber is usually around 180 ° C., but the polyethylene naphthalate fiber of the present invention has a low tan δ value with high orientation crystallization, and the fiber reinforced resin composition of the present invention is In the case of a molded product, advantageous characteristics in terms of impact resistance can be exhibited.

  The birefringence (ΔnDY) of the polyethylene naphthalate fiber is preferably in the range of 0.15 to 0.35. And as a density ((rho) DY), it is preferable that it is 1.350-1.370. When the birefringence index (ΔnDY) and density (ρDY) are small, a sufficiently developed fiber structure is not formed, and the heat resistance and dimensional stability of the fiber tend to decrease, and the physical properties of the final molded product also It tends to decrease. On the other hand, if the birefringence (ΔnDY) or density (ρDY) is increased too much, it is necessary to adopt conditions such as increasing the draw ratio to the vicinity of the break draw ratio in the production process, and yarn breakage is likely to occur and is stable. Since it is difficult to obtain a finished fiber, the physical properties of the final molded product tend to be difficult to improve. Further, the birefringence (ΔnDY) of the polyethylene naphthalate fiber is preferably in the range of 0.18 to 0.32, and the density (ρDY) in the range of 1.355 to 1.365.

  Polyethylene naphthalate fibers having the above characteristics have a higher melting point than conventional polyethylene naphthalate fibers, and can sufficiently exhibit performance even when used under high temperature conditions. The polyester processed yarn of the present invention comprising such a polyethylene naphthalate fiber is effectively used as a yarn for industrial materials for reinforcement requiring particularly high-temperature physical properties.

  Such polyethylene naphthalate fiber can be obtained, for example, by the following production method. That is, a method for producing a polyethylene naphthalate fiber in which a polymer whose main repeating unit is ethylene naphthalate is melted and discharged from a spinneret, and at least one kind represented by the following general formula (1) in the polymer at the time of melting After the addition of the phosphorus compound, a spinning draft ratio after discharging from the spinneret is 100 to 5000, and immediately after discharging from the spinneret, a heated spinning cylinder having a temperature within ± 50 ° C. of the molten polymer temperature is provided. It can be obtained by a production method that passes and stretches.

［上の式中、Ａｒは炭素数６〜２０個の炭化水素基であるアリール基であり、Ｒ^１は水素原子又は炭素数の１〜２０個の炭化水素基であるアルキル基、アリール基又はベンジル基、Ｘは、水素原子または−ＯＨ基である。］

[In the above formula, Ar is an aryl group which is a hydrocarbon group having 6 to 20 carbon atoms, and R ¹ is an alkyl group, an aryl group or a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms] A benzyl group, X is a hydrogen atom or —OH group. ]

  The polymer whose main repeating unit used for production is ethylene naphthalate can be produced according to a conventionally known polyester production method. That is, after an ester exchange reaction between a dialkyl ester of 2,6-naphthalenedicarboxylic acid represented by naphthalene-2,6-dimethylcarboxylate (NDC) and ethylene glycol as a glycol component as an acid component, this reaction is performed. The product can be heated under reduced pressure and polycondensed while removing excess diol component. Alternatively, it can also be produced by a conventionally known direct polymerization method by esterifying with 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol as a diol component.

  The transesterification catalyst used in the case of the method utilizing the transesterification reaction is not particularly limited, but from the viewpoint of the melt stability of the polyester, the hue, the small amount of insoluble foreign matter in the polymer, and the stability of spinning, Magnesium and zinc compounds are preferred. Also, the polymerization catalyst is not particularly limited, but is excellent in polyester polymerization activity, solid-phase polymerization activity, melt stability and hue, and the resulting fiber has high strength, excellent spinning properties and stretchability. In this respect, antimony compounds are particularly preferable.

Preferable compounds of the general formula (1) which are phosphorus compounds contained in the polymer at the time of melting include, for example, phenylphosphonic acid and phenylphosphinic acid.
Further, the hydrocarbon group of R ¹ used in the general formula (1) is preferably an alkyl group, an aryl group, or a benzyl group, and these may be unsubstituted or substituted. . At this time, it is preferable that the substituent of R ¹ does not inhibit the steric structure, and for example, a substituent substituted with a hydroxyl group, an ester group, an alkoxy group or the like is preferable. The aryl group represented by Ar in (1) above may be substituted with, for example, an alkyl group, an aryl group, a benzyl group, an alkylene group, a hydroxyl group, or a halogen atom.

［上の式中、Ａｒは炭素数６〜２０個の炭化水素基であるアリール基であり、Ｒ^２は水素原子又は未置換もしくは置換された１〜２０個の炭素元素を有する炭化水素基である。］ Among these, in order to improve crystallinity, the phosphorus compound is preferably phenylphosphonic acid represented by the following general formula (2) and derivatives thereof.

[In the above formula, Ar is an aryl group which is a hydrocarbon group having 6 to 20 carbon atoms, and R ² is a hydrogen atom or an unsubstituted or substituted hydrocarbon group having 1 to 20 carbon elements. is there. ]

  In the polyethylene naphthalate fiber used in the present invention, the crystallinity of polyethylene naphthalate is improved by adding these specific phosphorus compounds directly into the molten polymer, and the crystallinity is kept high under the subsequent production conditions. However, a polyethylene naphthalate fiber having a large crystal volume could be obtained. This is considered to be due to the effect of this specific phosphorus compound to suppress coarse crystal growth that occurs in the spinning and stretching steps and to finely disperse the crystals. In addition, it has been very difficult to spin polyethylene naphthalate fibers at high speeds. However, the addition of these phosphorus compounds has greatly improved spinning stability and is practical because it does not break. It became possible to increase the strength of the fiber by increasing the stretch ratio.

For stable production, the formula (1) will be described as an example. The carbon number of R ¹ is preferably 4 or more, more preferably 6 or more, and particularly preferably an aryl group. Further, since X is a hydrogen atom or a hydroxyl group, there is an effect that it is difficult to scatter in a vacuum during the process.

In order to show a high crystallinity improvement effect, R ¹ is preferably an aryl group, more preferably a benzyl group or a phenyl group. In the production method of the present invention, the phosphorus compound is phenylphosphinic acid. Or it is especially preferable that it is phenylphosphonic acid. Of these, phenylphosphonic acid and its derivatives are optimal, and phenylphosphonic acid is most preferable from the viewpoint of workability. Since phenylphosphonic acid has a hydroxyl group, it has a higher boiling point than other alkyl esters such as dimethyl phenylphosphonate, and has the advantage that it is difficult to scatter under vacuum. That is, the amount of the added phosphorus compound remaining in the polyester is increased, and the effect of comparing the added amount is increased. It is also advantageous in that the vacuum system is less likely to be clogged.

  For stable production, formula (1) will be described as an example. When X is a hydrogen atom or a hydroxyl group, there is an effect that it is less likely to be scattered under vacuum during the process. In order to show a high crystallinity improvement effect, it is preferable that the aryl group of Ar is further a benzyl group or a phenyl group. In the production method of the present invention, the phosphorus compound is phenylphosphinic acid or phenylphosphonic acid. It is particularly preferred that Of these, phenylphosphonic acid and its derivatives are optimal, and phenylphosphonic acid is most preferable from the viewpoint of workability. Since phenylphosphonic acid has a hydroxyl group, it has a higher boiling point than other alkyl esters such as dimethyl phenylphosphonate, and has the advantage that it is difficult to scatter under vacuum. That is, the amount of the added phosphorus compound remaining in the polyester is increased, and the effect of comparing the added amount is increased. It is also advantageous in that the vacuum system is less likely to be clogged.

  Although the polyethylene naphthalate fiber used in the present invention can be obtained by such a production method, the polyethylene naphthalate fiber contains 0.1 to 300 mmol% of phosphorus atoms with respect to the ethylene naphthalate unit. Is preferred.

  Further, it is preferable to add a metal element together with such a phosphorus compound, and further to add a divalent metal. In addition, it is preferable that at least one metal element selected from the group consisting of a metal element of 4th to 5th period and 3-12 group and Mg in the periodic table is added to the molten polymer. In particular, the metal element contained in the fiber is preferably at least one metal element selected from the group consisting of Zn, Mn, Co, and Mg. These metal elements may be added as a transesterification catalyst or a polymerization catalyst, or may be added separately. As content of such a metal element, it is preferable to contain 10-1000 mmol% with respect to an ethylene naphthalate unit. The P / M ratio, which is the abundance ratio of the phosphorus element P and the metal element M, is preferably in the range of 0.8 to 2.0.

The polyethylene naphthalate fiber having a crystal volume of 550 to 1200 nm ³ and a crystallinity of 30 to 60% used in the present invention is obtained by melting the polyethylene naphthalate polymer as described above and spinning it after discharging from the spinneret. The draft ratio is 100 to 5000, and it can be obtained by passing through a heat-insulated spinning cylinder set within a range of plus or minus 50 ° C. of the molten polymer temperature immediately after discharging from the spinneret and drawing.

Here, the spinning draft is defined as the ratio of the spinning winding speed (spinning speed) and the spinning discharge linear speed, and is expressed by the following (Equation 2).
Spinning draft = πD ² V / 4W (Formula 2)
(In the formula, D represents the hole diameter of the die, V represents the spinning take-up speed, and W represents the volume discharge amount per single hole)

  By increasing the spinning draft ratio, the crystal volume and crystallinity in the polymer can be increased. In order to obtain such a high spinning draft, the spinning speed is preferably high, preferably 1500 to 6000 m / min, and more preferably 2000 to 5000 m / min.

  Furthermore, in order to obtain such a polyethylene naphthalate fiber, it is preferable to pass through a heat-insulated spinning cylinder set within a range of plus or minus 50 ° C. of the molten polymer temperature immediately after discharging from the spinneret. Furthermore, it is preferable that the set temperature of the heat retaining spinning cylinder is not higher than the melt polymer temperature. Further, the length of the heat insulating spinning cylinder is preferably 10 to 300 mm, and more preferably 30 to 150 mm. The passing time of the heat-insulating spinning cylinder is preferably 0.2 seconds or longer.

  Usually, in the method for producing polyethylene naphthalate fiber, when a high draft condition is adopted as described above, a heated spinning cylinder that is several tens of degrees higher than the molten polymer temperature is used. This is because the polyethylene naphthalate polymer, which is a rigid polymer, is easily oriented immediately after being discharged from the spinneret, and is likely to cause single yarn breakage, so that it has been necessary to use a heated spinning cylinder to delay cooling. This is because when the spinning tube temperature is close to the molten polymer temperature, the delayed cooling state does not occur because the speed of the discharged polymer is high.

  However, the polyethylene naphthalate fiber used in the present invention can have a uniform structure even with the same degree of orientation by forming microcrystals using the specific phosphorus compound as described above. And since it has a uniform structure, no single yarn breakage occurs without using a heated spinning cylinder, and it is possible to ensure high yarn production. And it became possible to increase the crystal volume of the polyethylene naphthalate fiber more effectively by using such a low-temperature insulated spinning cylinder. This is because in a high-temperature spinning cylinder, the molecular motion in the polymer is intense and the formation of large crystals is hindered. By having a large crystal volume, the melting point and heat fatigue resistance of the resulting fiber can be effectively increased.

The spun yarn that has passed through the heat-insulating spinning cylinder is preferably cooled by blowing cold air of 30 ° C. or lower. Furthermore, it is preferable that it is a cold wind of 25 degrees C or less. The cooling air blowing rate is preferably ² to 10 Nm ³ / min, and the blowing length is preferably about 100 to 500 mm. Next, it is preferable to apply an oil agent to the cooled thread form.

  The undrawn yarn spun in this way preferably has a birefringence (ΔnUD) in the range of 0.10 to 0.28 and a density (ρUD) in the range of 1.345 to 1.365. When the birefringence index (ΔnUD) and the density (ρUD) are small, orientation crystallization of the fiber during the spinning process becomes insufficient, and heat resistance and excellent dimensional stability tend not to be obtained. On the other hand, if the birefringence index (ΔnUD) or density (ρUD) is too large, it is assumed that coarse crystal growth has occurred during the spinning process, which tends to inhibit spinnability and cause frequent breakage. Manufacturing tends to be difficult. Moreover, since the subsequent drawability is also inhibited, it tends to be difficult to produce fibers having high physical properties. Further, the birefringence (ΔnUD) of the spun undrawn yarn is more preferably in the range of 0.11 to 0.26, and the density (ρUD) is preferably in the range of 1.350 to 1.360.

  In order to obtain the fiber of the present invention, it is preferable to carry out a high spinning draft as described above. When drafting at a normal level, the crystal volume is small and the melting point is low, so that high dimensional stability cannot be obtained as in the present invention. On the other hand, when delayed cooling is performed using a heated spinning cylinder even with a high-spinning draft, the crystal volume is also small and the melting point is low, and the dimensional stability is high unlike the case of using the insulated spinning cylinder of the present invention. Because you can't get.

  After that, stretching is performed. However, when the production is performed under such conditions, the high-spinning draft is performed on the fibers having uniform crystals, so that the yarn breakage is effectively prevented. And although the degree of crystallinity is high, fibers with a large crystal volume can be obtained. Stretching may be performed by winding it once from a take-up roller and stretching it by a so-called separate stretching method, or by stretching it by a so-called direct stretching method in which undrawn yarn is continuously supplied from the take-up roller to the stretching process. I do not care. The stretching conditions are one-stage or multi-stage stretching, and the stretching load factor is preferably 60 to 95%. The drawing load factor is the ratio of the tension at the time of drawing to the tension at which the fiber actually breaks. By increasing the draw ratio and the draw load factor, the crystal volume and crystallinity can be effectively increased.

  The preheating temperature at the time of drawing is preferably performed at a temperature not lower than the glass transition point of the polyethylene naphthalate undrawn yarn and not higher than 20 ° C. lower than the crystallization start temperature, and preferably 120 to 160 ° C. The stretching ratio depends on the spinning speed, but it is preferable to perform stretching at a stretching ratio that gives a stretching load factor of 60 to 95% with respect to the breaking stretch ratio. Further, in order to maintain the strength of the fiber and improve the dimensional stability, it is preferable to perform heat setting at a temperature from 170 ° C. to the melting point of the fiber or less in the drawing process. Furthermore, it is preferable that the heat setting temperature at the time of Enjin is in the range of 170 to 270 ° C. By such heat setting at a high temperature, the draw ratio can be effectively increased and the crystal volume can be increased.

  In the above production method, by using a specific phosphorus compound, it is possible to adopt a cooling condition with a high draft rate and a heat-retaining spinning cylinder, and a high dimensional stability and fatigue resistance even though it is a production method with high yarn production properties. It was possible to obtain the most suitable fiber for the present invention. By the way, when not using the specific phosphorus compound described above, it is necessary to lower the draft rate for spinning or delay cooling using a heated spinning cylinder, which has the high physical properties and high melting point required in the present invention. You can't get fiber.

The polyethylene naphthalate fiber obtained by such a production method has a high crystal volume and a high crystallization rate, has a high melting point and a high dimensional stability as well as high strength, and also has excellent resistance to resistance. It becomes a fiber that also satisfies fatigue properties, and can be effectively used for the polyester processed yarn of the present invention.
Now, the polyester processed yarn of the present invention has fluffs made of polyethylene naphthalate fibers as described above on the surface.

  As a method for obtaining the polyester processed yarn of the present invention, for example, as a method for producing a check yarn, it can be produced by an apparatus as shown in FIG. This will be described more specifically with reference to the drawings. First, the filament A of polyethylene naphthalate fiber passes through the supply nip roller 1 while being combined in front of the supply nip roller 1, and then is simultaneously torn at the check position 2 by the check nip roller 3, and is uniformly drafted. To get a short fiber bundle. Next, the air is pulled off from the check roller 3 by the suction air nozzle 4, and further, the swirl conjugation nozzle 5 is wound with the fluff of short fibers together with the entanglement, and is then taken up by the delivery roller 6. As a result, the check yarn B is obtained in which fluffs of short fibers are randomly wound. Here, it is preferable that the filament yarn of the polyethylene naphthalate fiber to be subjected to the checkering machine is combined just before the checkering as described above. The total number of yarns before processing is preferably set to be 8000 dtex or more and 10,000 dtex or less, and the fineness of the check yarn after the check processing is preferably set to 400 dtex or more and 700 dtex or less. That is, the fineness of the entire filament to be input to the check processing and the check yarn after the check processing so that the check magnification (= fineness of the combined yarn filament / fineness of the check yarn) is 15 times or more and 20 times or less. It is preferable to adjust the fineness. If the check magnification is too low, the generation of fuzz is small, and conversely if the check magnification is too high, the yarn is cut and stable check processing tends to be difficult.

  The polyethylene naphthalate-processed yarn of the present invention preferably further obtains a desired fiber cord by twisting or combining yarns. Furthermore, an adhesion treatment agent can be applied to the surface to further increase the adhesive force. As an adhesive treatment agent, for example, for rubber reinforcement applications, it is optimal to treat an RFL adhesive treatment agent, and it is also a preferable method to perform pretreatment with an epoxy compound before the RFL adhesive treatment.

  More specifically, such a fiber cord is subjected to heat treatment by adding a twisted yarn according to a conventional method to the polyethylene naphthalate check yarn of the present invention or by attaching an RFL treatment agent in a non-twisted state. Such a fiber becomes a treated cord that can be suitably used for rubber reinforcement.

  The polyester processed yarn of the present invention thus obtained can be made into a fiber / polymer composite by reinforcing the polymer. At this time, the polymer is preferably a rubber elastic body. This is because the effect of improving the adhesion by fluff is particularly effective. And this composite_body | complex becomes very excellent in the moldability when it is set as a composite_body | complex since the polyethylene naphthalate check yarn of this invention used for reinforcement is excellent in heat resistance and dimensional stability. Moreover, since the polyethylene naphthalate check yarn of the present invention intentionally generates fluff by performing check processing, it is excellent in adhesiveness with a polymer and has a higher reinforcing effect. Furthermore, since polyethylene naphthalate fibers are stretched to the limit by the check-off process, the single yarn strength of the polyethylene naphthalate check yarn is higher than the single yarn strength of the polyethylene naphthalate fiber before the check processing, The reinforcing effect can also be enhanced by further increasing the adhesiveness of.

  The present invention will be further described in the following examples, but the scope of the present invention is not limited by these examples. Various characteristics were measured by the following methods.

(1) Intrinsic viscosity IVf
The chip or fiber was dissolved in a mixed solvent of phenol and orthodichlorobenzene (volume ratio 6: 4) and measured at 35 ° C. using an Ostwald viscometer.

(2) Strength of polyethylene naphthalate check yarn Measured according to JIS L1013.

(3) Strength utilization rate The strength utilization rate (%) before and after the check-off processing was calculated by the following formula.
(Strength of parent yarn) / (Strength of check yarn) × 100
Parent yarn: Polyethylene naphthalate fiber before check-out.

(4) Strength retention at high temperature The strength of polyethylene naphthalate check yarn was measured in the same manner as (2) in an atmosphere at 100 ° C., and the strength retention (%) at high temperature was calculated according to the following formula.
(Strength at 100 ° C.) / (Strength at normal temperature) × 100

(5) Dry heat shrinkage rate of fiber Based on JIS L1013 B method (filament shrinkage rate), the shrinkage rate was 180 ° C. for 30 minutes.

(6) Crystallinity of fiber First, the specific gravity of the fiber was measured at 25 ° C. using a carbon tetrachloride / n-heptane density gradient tube. From the specific gravity thus obtained, the crystallinity was determined from the following (Equation 1).
Crystallinity Xc = {ρc (ρ−ρa) / ρ (ρc−ρa)} × 100 (Equation 1)
In the formula, ρ: specific gravity of polyethylene naphthalate fiber ρa: 1.325 (complete amorphous density of polyethylene naphthalate)
ρc: 1.407 (complete crystal density of polyethylene naphthalate)

（ここで、Ｄは結晶サイズ、Ｂは回折ピーク強度の半価幅、Θは回折角、λはＸ線の波長（０．１５４１７８ｎｍ＝１．５４１７８オングストローム）を表す。）
より算出し、下式により結晶１ユニットあたりの結晶体積とした。
結晶体積（ｎｍ^３）＝結晶サイズ（２Θ＝１５〜１６°）×結晶サイズ（２Θ＝２３〜２５°）×結晶サイズ（２Θ＝２５．５〜２７°） (7) Fiber crystal volume Fiber crystal volume was determined by wide-angle X-ray diffraction using a D8 DISCOVER with GADDS Super Speed manufactured by Bruker.
The crystal volume is determined from the full width at half maximum of the diffraction peak intensity at 2Θ of 15 to 16 °, 23 to 25 °, and 25.5 to 27 ° in the wide-angle X-ray diffraction of the fiber. Formula 3),

(Where D is the crystal size, B is the half width of the diffraction peak intensity, Θ is the diffraction angle, and λ is the X-ray wavelength (0.154178 nm = 1.54178 angstrom).)
The crystal volume per unit of crystal was calculated by the following formula.
Crystal volume (nm ³ ) = crystal size (2Θ = 15-16 °) × crystal size (2Θ = 23-25 °) × crystal size (2Θ = 25.5-27 °)

(8) Melting point Tm
Using a Q10 differential scanning calorimeter manufactured by TA Instruments, the temperature of an endothermic peak that appeared when a sample of 10 mg was heated to 320 ° C. under a temperature rising condition of 20 ° C./min under a nitrogen stream was defined as the melting point Tm.

(9) Rubber adhesiveness 25 cords were evaluated by the adhesive strength when peeling from the rubber. The check yarn cord was made by aligning three 560 dtex processed yarns (check yarn) and adding 100 T / m twist in the S direction to produce a 1680 dtex check cord. Further, as a cord of the raw yarn (filament yarn), a 1680 dtex raw yarn was added to the S direction in a twist of 100 T / m to produce a 1680 dtex filament cord. On the other hand, as evaluation rubber, H-NBR rubber produced with the following composition was used.
(Composition composition of H-NBR rubber)
Carbon black: 50 parts Zinc oxide: 5 parts Plasticizer TOTM: 5 parts Stearic acid: 0.5 parts Antioxidant (Naugard 445): 1.5 parts Anti-aging agent (NOCRACK MBZ): 1 part Silica: 8 parts

[Example 1]
In a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 50 parts by weight of ethylene glycol, 0.030 parts by weight of manganese acetate tetrahydrate and 0.0056 parts by weight of sodium acetate trihydrate were stirred, Charged to a reactor equipped with a methanol distillation condenser, the temperature was gradually raised from 150 ° C to 245 ° C, and the ester exchange reaction was carried out while distilling the methanol produced as a result of the reaction out of the reactor. Before the exchange reaction was completed, 0.03 part by weight (50 mmol%) of phenylphosphonic acid (PPA) was added. Thereafter, 0.024 parts by weight of diantimony trioxide is added to the reaction product, transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port and a distillation apparatus, heated to 305 ° C., and 30 Pa or less. A condensation polymerization reaction was performed under high vacuum, and a chip was formed according to a conventional method to obtain a polyethylene naphthalate resin chip having an intrinsic viscosity of 0.62. This chip was preliminarily dried at 120 ° C. for 2 hours under a vacuum of 65 Pa, and then subjected to solid phase polymerization at 240 ° C. for 10 to 13 hours under the same vacuum to obtain a polyethylene naphthalate resin chip having an intrinsic viscosity of 0.74.
This chip was spun from a spinneret having a diameter of 0.8 mm and a 500 hole diameter at a polymer melting temperature of 310 ° C., and was heated to 330 ° C. with a length of 50 mm provided directly under the die (heat-retaining spinning cylinder). Then, a cooling air adjusted to a humidity of 25 ° C. and 65% RH is blown from a cylindrical chimney with a blowing distance of 450 mm to cool the spun yarn, and then an oil agent that is metered and supplied by an oil agent applicator is applied. Then, it was taken up at a speed of 2500 m / min with a roller. Next, the unstretched yarn was used for the following stretching process. The draw ratio was set so that the draw load factor was 92% with respect to the break draw ratio.

That is, as the drawing process, after applying 1% pre-stretch to the undrawn yarn, the first-stage drawing is performed between the 150 ° C. heating supply roller rotating at a peripheral speed of 130 m / min and the first-stage drawing roller. Next, a constant-length heat set is passed through a non-contact type set bath (length 70 cm) heated to 230 ° C. between the first-stage stretching roller heated to 180 ° C. and the second-stage stretching roller heated to 180 ° C. After going, it was wound on a winder. The obtained drawn yarn had a fineness of 1680 dtex, a crystal volume of 952 nm ³ (952000 angstrom ³ ), and a crystallinity of 47%. The strength of the obtained polyethylene naphthalate fiber was 7.4 cN / dtex, 180 ° C. dry yield 2.6%, melting point 297 ° C., and was excellent in high heat resistance and low shrinkage.
Five unprocessed 1680 dtex polyethylene naphthalate fibers were combined and performed at a check length of 1 m, a processing speed of 200 m / s, and a supply speed of 13 m / s. went. The fineness of the obtained polyethylene naphthalate-processed yarn (checkout yarn) was 560 dtex. Table 1 shows the physical properties of the obtained processed yarn.

[Example 2]
In Example 1, a polyethylene naphthalate-processed yarn (checkout yarn) was obtained in the same manner as in Example 1 except that the number of holes in the spinneret was changed from 500 to 249. The physical properties of the obtained processed yarn are also shown in Table 1.

[Comparative Example 1]
The polymerization of polyethylene-2,6-naphthalate was carried out in the same manner as in Example 1 except that 40 mmol% of regular phosphoric acid was added instead of phenylphosphonic acid (PPA), which is a phosphorus compound, before the transesterification reaction was completed. Thus, a polyethylene naphthalate resin chip (intrinsic viscosity 0.75) was obtained. Using this resin chip, melt spinning was carried out in the same manner as in Example 1. However, it was not possible to produce the yarn satisfactorily due to frequent yarn breakage during spinning.
Therefore, the spinning speed of Example 1 was changed from 2500 m / min to 496 m / min, and other conditions were changed. That is, in order to match the fineness of the obtained fiber, the cap base diameter was changed from 0.8 mm to 0.55 mm, the temperature of the heat-retaining spinning cylinder just below the base was changed to 400 ° C., and the length was changed to 250 mm, and undrawn yarn Got. Further, the subsequent draw ratio was changed from 1.08 times of Example 1 to 5.65 times to obtain drawn yarns. The obtained drawn yarn had a crystal volume of 298 nm ³ (298000 Å ³ ) and a crystallinity of 48%. The strength of the obtained polyethylene naphthalate fiber was 7.4 cN / dtex, 180 ° C. dry yield 6.0%, melting point 271 ° C. and poor heat resistance.
Using the obtained polyethylene naphthalate fiber, a check-out process was performed in the same manner as in Example 1. The physical properties of the obtained processed yarn are also shown in Table 1.

[Comparative Example 2]
The polyethylene naphthalate fiber obtained in Comparative Example 1 was used as an unprocessed filament yarn that was not subjected to a check-out process. The adhesiveness was evaluated using this yarn, but the peel strength was inferior. The obtained physical properties are also shown in Table 1.

  The polyester processed yarn of the present invention thus obtained is characterized by excellent dimensional stability and heat resistance and good adhesiveness while having a high modulus. It can be used in industrial material applications that require these characteristics, and is particularly useful in reinforcement applications such as rubber reinforcement applications such as tires, belts and hoses.

DESCRIPTION OF SYMBOLS 1 Supply nip roller 2 Check position 3 Check nip roller 4 Suction air nozzle 5 Turning conjugation nozzle 6 Delivery roller A Unprocessed thread (filament)
B Polyester processed yarn (Check yarn)

Claims (6)

A polyester processed yarn having fluffs made of polyethylene naphthalate fiber on the surface, the crystal volume obtained from X-ray wide-angle diffraction of the polyethylene naphthalate fiber is 550 to 1200 nm ³ , and the crystallinity is 30 to 60%. Polyester processed yarn characterized by being.   The polyester processed yarn according to claim 1, wherein the polyester processed yarn is a check yarn.   The polyester processed yarn according to claim 1 or 2, wherein the polyethylene naphthalate fiber contains 0.1 to 300 mmol% of phosphorus atoms with respect to ethylene naphthalate units.   The polyester processed yarn according to claim 3, wherein the phosphorus atom in the polyethylene naphthalate fiber is derived from phenylphosphinic acid or phenylphosphonic acid.   The polyester processed yarn according to any one of claims 1 to 4, wherein the polyethylene naphthalate fiber contains a metal element.   A fiber polymer composite reinforced with the polyester processed yarn according to any one of claims 1 to 5.

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