JP2010163724A - Method for producing polyester fiber used as industrial material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester which is, without giving damage to a yarn thread traveling on rolls, capable of inhibiting the development of fluffs even on spinning at a high speed, and without reducing fluff quality even in the production for a long period of time. <P>SOLUTION: The roll used for the production of the polyester used for an industrial material by a direct spinning and stretching is provided by blasting a part or the whole surface of a base material 1 of the roll, and further applied with a diamond like carbon coating film 3 excellent in close adhesion with hard chromium plating and formed by a plasma base ion injection film-forming method on the surface of the roll treated with the hard chromium plating 2 finished as satin finished surfaces. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a high-quality polyester fiber by continuously drawing at a high speed without winding up an undrawn yarn made of a melt-spun polyester fiber for industrial materials.

  Polyester fibers are well used not only for clothing but also for industrial materials because they have excellent performance with a good balance in strength, elastic modulus, dimensional stability, and the like. In particular, polyester fibers used for heavy fabrics such as seat belts and tents are required not only to have high strength, but also to have less fluff caused by single yarn breakage during stretching. Furthermore, the cost of such industrial material fibers is extremely strong, and the production speed has been increasing year by year in accordance with the recent progress in drawing technology and winding equipment. Is significantly increased, and further suppression of fluff is required.

  Usually, high-strength polyester fibers are produced by two or more stages of multi-stage drawing, but it is known that most of the raw yarn fluff is generated on the final drawing roll. The root cause of this fluff generation is greatly influenced by melt spinning conditions, properties of the spinning oil, etc., but the yarn is scratched directly on the drawing roller, resulting in the occurrence of hair streaks. It can be said that the occurrence of fuzz greatly depends on the surface finish state of the contact surface of the drawing roller.

  Conventionally, hard chrome plating (hereinafter also referred to as “HCr plating”) and various ceramic spray coatings have been used as the surface treatment of drawing rolls used in apparatuses for directly spinning and drawing industrial polyester fibers. .

  At this time, the hard chrome plating used for the surface treatment of the drawing roll is required to obtain an appropriate coefficient of friction in order to prevent winding with the yarn running on the hard chrome plating. Therefore, for this purpose, the surface roughness is adjusted by forming irregularities consisting of a combination of a mirror surface and a satin surface, or only a satin surface. At that time, the textured portion where the unevenness is formed is required to have a smooth uneven shape with little damage to the yarn running on the surface by performing hard chrome plating to an appropriate plating thickness.

  For the reasons described above, in order to suppress the occurrence of fluff on the yarn, it is appropriate to apply hard chrome plating as the surface film of the drawing roll. However, hard chrome plating has a lower surface hardness than various ceramics. In addition, since the hardness further decreases when heated, compared to normal temperature, when manufacturing industrial polyester fiber using a heated drawing roll, the wear resistance of the hard chrome plating film is lowered and durability is increased. There was a big problem.

  Therefore, in order to suppress the progress of the wear of the roll surface with the passage of time as described above, various hard coatings having a high hardness are applied by a thermal spraying method instead of the hard chrome plating. However, in this case, it is very difficult to form a ceramic film accurately and smoothly with a uniform thickness.

  Therefore, in order to obtain a uniform thickness, grinding is performed after the thermal spray film formation. However, when grinding is performed, the surface of the ceramic sprayed coating will have an infinite number of fine and sharp projections distributed. Therefore, polishing is usually performed so that a predetermined surface roughness is obtained after this grinding. Do.

  However, this fine and sharp protrusion cannot be removed completely, damages the yarn running on the drawing roll, causes single yarn breakage, and causes fluff. This becomes more conspicuous as the production speed of the fiber increases, and there is a restriction that the production speed must be lowered when applied to a fiber having a relatively low fluff quality requirement level such as a tire cord.

From the background described above, a technique for forming a high-hardness film that can suppress damage to the yarn, has a smooth surface form, and has durability is required. As such a conventional technique, for example, Patent Document 1 proposes a technique for forming a hard film composed of fine Cr ₂ O ₃ by chemically changing CrO ₃ on a roll base material. In Document 2, etc., a hard layer such as hard chrome plating is formed on the roll base material, and an amorphous hydrogenated carbon coating film (hereinafter referred to as “DLC coating film”) is formed on the hard layer via an intermediate layer. Technologies etc. have been proposed.

  However, the technique of the former (Patent Document 1) is a technique of repeating the process of heating to a high temperature of 500 to 600 ° C. to form a dense film on the surface and increasing the hardness. Therefore, depending on the material, there is a risk of damaging the base material itself. In particular, with the wear of the film, it is not preferable for a roll on the premise that the film is removed and re-executed.

  On the other hand, in the latter technique (Patent Document 2), a plasma CVD method is a general method as a conventional method for applying a DLC coating film. This plasma CVD method is a technique in which an introduced gas is turned into plasma at a high frequency and is chemically reacted and deposited on the surface portion where the activated carbon element is coated.

  However, there is a problem that the chemical bonding force between the member surface and the DLC coating film is weak and adhesion is poor. Therefore, there is a problem in that the surface of the coating object has a low adhesion to an uneven shape such as a satin shape, and a film is missing. Because of this problem, since it is usually possible to construct only a film thickness of about 1 to 2 μm, there is a possibility that a pinhole in which a film is not formed may occur. In addition, DLC coating films have high hardness but have problems such as easy peeling and cracking.

Japanese Unexamined Patent Publication No. Sho 63-317680 JP-A-10-29762

  An object of the present invention is to solve the problems of the prior art, and even if yarns are produced at a high speed, the yarn running on the roll is not damaged and the generation of fluff is suppressed. Another object of the present invention is to provide a method for producing polyester. It is another object of the present invention to provide a method for producing a polyester that does not deteriorate the fluff quality even during long-term production.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the problem can be solved by the following drawing rolls.

Here, as the present invention for solving the above-mentioned problems, “spinning as a melted polyethylene terephthalate polyester yarn, heating the yarn immediately after spinning, solidifying it by cooling and taking it off, The unstretched yarn obtained is continuously stretched in one or more stages without being wound once, and the stretched yarn immediately after stretching is taken up at 4000 m / min or more, and finally the drawn yarn In the manufacturing method of the polyester fiber for industrial materials that winds up the strip,
With respect to the drawing roll group used when the undrawn yarn is subjected to heat drawing treatment, at least a part or the entire surface of the yarn contact surface on the base material of the final drawing roll is subjected to roughening treatment and then hard chrome plating. And adopting a drawing roll having a diamond-like carbon coating film formed by a plasma-based ion implantation / film-forming method by finishing the surface of the satin surface having a spherical surface with a convex portion of the contact surface. The manufacturing method of polyester fiber for industrial materials is provided.

  According to the present invention, it is possible to stably produce high-strength polyester fibers at a high speed of 4000 m / min or more by direct spinning and drawing with little fuzz or yarn breakage, and renewal of the surface coating applied to the drawing roll. There is a remarkable effect that the period can be made sufficiently long in practice.

It is the front sectional view which illustrated typically the extending roll used for the present invention. 1 is a schematic view of a plasma-based ion implantation / deposition apparatus that is a method of applying a DLC coating film to a stretching roll. It is a schematic apparatus block diagram which comprises the manufacturing process of the polyester fiber which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front cross-sectional view schematically illustrating a drawing roll of the present invention. In the reference symbols in the figure, 1 is a roll shell, 2 is a hard chromium film formed on the roll contact surface, and 3 is a DLC. It is a coating film.

  In the drawing roll of the present invention, first, a cleaning process is performed by degreasing or the like on the outer peripheral surface (thread contact surface) of the roll shell 1 formed of a base material made of chromium molybdenum steel or the like. Further, a sandblasting process and a buffing finish are applied as in the prior art to form a satin surface having fine surface irregularities having a smooth spherical shape and an appropriate surface roughness on the yarn contact surface. These finishes can adopt a surface form as described in, for example, Japanese Patent Application Laid-Open No. 2005-68618, and these surface finishes also reduce the coefficient of friction with the yarn.

  Next, hard chrome plating by electrolytic plating is applied to the contact surface of the roll shell to form the hard chrome plating film 2. At this time, the film thickness of the hard chrome plating film 2 is desirably 20 to 80 μm, and particularly preferably 30 to 50 μm. Due to the balance between the film thickness and the roughening treatment combining the sandblasting treatment and the polishing finishing treatment, a surface form having a preferable spherical shape is formed on the satin finish. The picker hardness of the hard chrome plating film 2 is desirably 900 Hv or more.

  A DLC coating film 3 is further formed on the hard chromium film 2 formed as described above. At this time, it is important to form the DLC coating film 3 while maintaining the surface form of the hard chrome plating film 2 having the preferable surface form having a smooth spherical shape.

  The present invention is characterized by using a stretching roll on which the DLC coating film 3 having such a smooth spherical surface form is formed. Therefore, the method for forming the DLC coating film 3 will be described in more detail below.

  First, a schematic diagram of a plasma-based ion implantation / film formation apparatus is shown in FIG. In FIG. 2, reference numeral 4 denotes a stretching roll having a hard chrome plating film 2 on which a DLC coating film 3 is formed. Reference numeral 5 denotes a vacuum chamber, and reference numeral 6 denotes an exhaust device for maintaining the inside of the vacuum chamber 5 at a predetermined degree of vacuum. Further, reference numeral 7 is an inlet for introducing a hydrocarbon gas, reference numeral 8 is a high-frequency plasma source for forming hydrocarbon gas plasma, and reference numeral 9 is a metal element for improving the adhesion of the DLC coating film 3. Is a metal plasma source for ion implantation.

  Next, reference numeral 10 denotes a high voltage negative pulse power source for applying a high voltage negative charge to the target stretching roll 1, and reference numeral 11 denotes a radio frequency (RF) power source. Here, the high voltage negative pulse power supply 10 generates a negative charge having a predetermined energy, and applies a negative charge pulse to the stretching roll 1 through a high voltage feedthrough 12. The feedthrough 12 is connected to an installation table (not shown), and this installation table is an insulator 13 and is in an electrically floating state.

  Further, when the DLC coating film is formed, power can be supplied from the high voltage feedthrough 12 through the superimposing device 14 that superimposes the high voltage pulse and the high frequency so that the supply gas can be converted into plasma so that the film can be formed. It is configured. A shield cover 15 is attached to the high voltage feedthrough 12 to protect the feedthrough 12.

  Hereinafter, the film forming method will be described in order. The inside of the vacuum chamber 5 is brought to a predetermined degree of vacuum suitable for film formation by the exhaust device 6, and argon gas is introduced to generate argon plasma to clean the roll surface with argon ions. After that, Si ions are introduced to improve the adhesion of the film, and carbon ions are introduced with high energy.

  The carbon ions introduced by such a construction method are implanted to a depth of 50 nm or more from the target surface of the drawing roll 1, whereas in the plasma CVD method or the PVD method, carbon atoms have a depth of 10 nm or more from the surface. It is never injected. Therefore, this difference leads to a difference in adhesion performance of the DLC coating film 3. Finally, the DLC coating film 3 is formed with relatively low energy while carbon ions are implanted, and the formation of the DLC coating film 3 is completed.

  At this time, the thickness of the DLC coating film 3 in FIG. 1 is desirably 2 to 50 μm, more preferably 5 μm or more. Further, it is desirable that the DLC coating film 3 has a Pickers hardness of about 1000 to 4000 Hv.

DLC coating provides a high hardness film of 5000 Hv or more depending on the film formation process, raw materials used, film formation conditions, and the like. However, on the other hand, there are problems such as high internal stress and easy peeling and cracking. In order to avoid this problem, the life and performance of the coating are improved when the hardness is reduced to an appropriate range in order to reduce the internal stress. Accordingly, in the present invention, it is desirable that the Picker hardness of the DLC coating film 3 is about 1000 to 4000 Hv.
The drawing roll apparatus described above is particularly suitable for drawing high-strength polyester fibers for seat belts at high speed. Hereinafter, the manufacturing method will be described.

  In the method for producing a polyester fiber of the present invention, a melted polyethylene terephthalate polyester is spun from a spinneret pack, and the spun yarn is cooled after passing through a heating cylinder disposed immediately below the polymer discharge surface of the spinneret. Solidify and take over. At this time, without winding up the obtained undrawn yarn, the drawn yarn is continuously drawn by a group of one or more drawing rolls and wound up through the final roll. At this time, in the present invention, the rotation speed of the final stage drawing roll is 4000 m / min or more, and at least the final stage drawing roll uses the drawing roll apparatus according to the present invention to produce polyester fiber. Is a major technical feature.

  The polyethylene terephthalate-based polyester that is the subject of the present invention is a polyester having ethylene polyethylene terephthalate as a main repeating unit and does not impair the object of the present invention, for example, 10% mol or less based on the acidic content, Preferably, the polyester may be 5% mol or less and copolymerized with other components. Preferred copolymerization components include isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, sulfoisophthalic acid, sodium salt, acid component such as sulfoisophthalic acid tetrabutylphosphonium salt, ethylene glycol, 1, 4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, 2,2-bis {4- (2-hydroxyethoxy) phenyl} propane, polyethylene glycol having a molecular weight of 4000 or less Such a glycol component is mentioned.

In the present invention, in order to obtain fibers having higher strength and durability, it is preferable to solid-phase polymerize the polyester to have an intrinsic viscosity of 0.90 or more.
Next, the manufacturing method of the polyester fiber based on this invention is demonstrated in detail, referring FIG.

  In the production method of the present invention, the melted polyester is spun from the spinneret pack 24, the spun yarn is heated by passing through a heating cylinder 11 provided immediately below the polymer discharge surface of the spinneret, The spinning oil is applied to the yarn solidified by oil agent application means such as the oiling roll 12 and taken up by the take-up roll 18.

  Next, the undrawn yarn obtained in this manner is continuously drawn without being wound once, and is drawn by the one or more drawing roll group 20.21, and then wound through the final roll 22. In this case, for example, the undrawn yarn is preheated with the preheated drawing roll 19, and the first drawing is performed 3.0 to 4.0 times with the drawing roll 20. The second stage of drawing is performed so that the draw ratio is 5.0 to 7.0, and the running yarn is relaxed between 0 and 4% with the relaxing roll 22 as the final roll, and the relaxation heat treatment is performed. It is possible to preferably adopt a method of performing and finally winding up on the winder 23.

  In the polyester production method according to the present invention, it is important to use the roll group 19.20.21.22 constituting the stretching roll apparatus for the final-stage stretching roll 21 and the relaxation roll 22, thereby Even when these rolls are rotated at a high speed of 4000 m / min or more, fluff generated on the running yarn due to scratch damage is extremely reduced, and high-quality stretched polyester fibers are stable over a long period of time. Can be manufactured.

The present invention will be specifically described below with reference to examples and comparative examples. In addition, the characteristic described in the Example was measured with the following method.
Hereinafter, the present invention will be described in more detail by experimental examples performed on the stretching roll according to the present invention. The characteristics described in the series of experimental examples were measured according to the following method.

  (1) Stretch roll surface temperature (° C): The roll surface is coated with black paint, and the surface of the roll rotating at a peripheral speed of 3663 m / min is applied to the roll with a non-contact type radiation thermometer (HORIBA IT-530S). Measurement was made at a pitch of 30 mm from the root, and the difference between the maximum value and the minimum value was defined as the temperature distribution width.

  (2) Picker's hardness (Hv): A test piece was prepared and measured with a load of 300 g applied to the measurement object in accordance with JIS Z2244.

  (3) Surface roughness (Ry): The applied roll surface was measured by a palpation scanning test method in accordance with JIS B0601-1982.

  (4) Fluff count: Using a fluff measuring device (MEINER-DEL's fluff detector, model: BFD-8P-B type) for the running yarn, per yarn length of 10,000 m The number of fluff generated was counted.

  (5) Abrasion degree: In the abrasion test conducted in advance, take a replica photograph of the surface abrasion state of the measurement sample in time series, set the abrasion grade, and evaluate the abrasion resistance by grading the abrasion degree. It was. As for the grade, “1” is the most excellent, and the grade difference is set in 10 ranks between the state of no wear and the complete wear state (the satin finish is almost disappeared).

  (6) Cutting strength and cutting elongation: measured according to JIS L 1013.

  (7) Breakage: The number of breaks per ton in terms of the polymer weight used for yarn production, and the number of breaks of less than 0.55 times / T is considered “good”. Of 0.55 times / T or more was regarded as “bad”.

  (8) Renewal period of roll surface: Direct spinning drawing described later is continuously performed, and the surface roughness is measured at intervals of 30 days by the above-described method, and Ry is smaller than 2 μm or the surface roughness Ra is smaller than 5 μm. The update cycle was taken when the time became smaller.

  The drawing roll apparatus used for drawing the polyester fiber according to the present invention is formed by forming the DCL coating illustrated in FIG. 1 using the plasma-based ion implantation / film formation method (PBII / D) (in “Table 1” below). “Sample 1”) described in 1) was used. Moreover, in the following "Table 1", what applied only hard chromium (HCr) plating was also shown as "Sample 2". Further, a sample having the same configuration as that of “Sample 1” and having a DLC coating applied by plasma CVD is shown as “Sample 3”.

  The three types of “Sample 1”, “Sample 2”, and “Sample 3” were each heated to 200 ° C., and a fretting experiment with the yarn was conducted for 5 hours. In the experiment, an evaluation pin (φ12) aimed at a surface roughness of 6S was placed between the rollers of the test drawing machine (tensile 3000 g), and the yarn contacted at an angle of about 75 °. After the experiment, the yarn contacted. The wear was evaluated by observing an enlarged photograph of the surface at the position.

  As is apparent from Table 1, the drawn roll produced by the construction method of the present invention has the same generation of fuzz as that of the hard chrome plating, but wear is remarkably reduced, and the roll renewal life is epoch-making. The possibility that it can be extended is confirmed. In addition, it was confirmed that the film formation defects and peeling that were problems in the DLC coating film by the plasma CVD method did not occur.

  Next, among the three types of “Sample 1”, “Sample 2” and “Sample 3” described above, “Sample 1” having the most excellent roll performance is used as follows. Polyester for industrial materials showing excellent quality as a seat belt was manufactured, and the superiority of its physical properties was confirmed.

  First, as a polymer, a polyethylene terephthalate chip having an intrinsic viscosity of 0.62 was preliminarily dried at 130 ° C. for 2 hours and then solid-phase polymerized at 230 ° C. for 9 hours under a vacuum of 133 Pa. A polyester fiber was obtained through the fiber manufacturing process illustrated in FIG.

  That is, a chip whose intrinsic viscosity has been increased to 1.00 by performing the above-described solid-phase polymerization is put into an extruder, melt-extruded, and melted from a spinneret attached to a spinneret pack 24 attached to a spin block. Spinning was performed at a temperature of 290 ° C. The spun yarn is passed through a heating cylinder 11 having a length of 300 mm and an internal ambient temperature set to 350 ° C., and the side of the yarn that runs cooling air whose temperature is controlled to 25 ° C. The solution was cooled and solidified. Further, to this cooled and solidified yarn, a spinning oil is applied while adjusting the oil agent pick-up amount of the yarn that has been drawn by the oiling roll 12 to 0.5%, and the take-up roll 18 applies 1020 m / It was taken up as an undrawn yarn at a rate of minutes.

  Following the take-up of the undrawn yarn, it is continuously preheated to about 100 ° C. by the preheating roll 19 without being wound once, and the surface temperature is increased to 3.0 times between the drawing roll 20 heated to about 140 ° C. Stretched. Subsequently, the film was preheated so as to be easily stretched, and the remaining stretch was performed between the stretch roll 21 and the total stretch ratio so as to be 4.4 times. The drawn fiber thus obtained is subjected to a relaxation heat treatment with a relaxation roll 22 so that the relaxation rate is 3%, wound on a winder 23 at a speed of 4500 m / min, and a polyester of 1110 dtex / 96 fil. Fiber was obtained. The obtained drawn fiber had a cutting strength as high as 9 cN / dtex, and physical properties equivalent to or higher than those obtained using “Sample 2” and “Sample 3” were obtained.

  According to the method for producing a polyester fiber of the present invention, it is possible to produce a polyester fiber for industrial materials that requires a strict fuzz quality such as a seat belt with a quality that meets the application standards.

1 Roll shell 2 Hard chromium film 3 DLC coating film 4 Roll 5 Vacuum chamber 6 Exhaust device 7 Gas inlet 8 High frequency plasma source 9 Metal plasma source 10 High voltage negative pulse power source 11 High frequency (RF) power source 12 Feedthrough 13 Insulator 14 Superimposing device 15 Shield cover 16 Heating cylinder 17 Oiling roll 18 Take-up roll 19 Preheating roll 20 First drawing roll 21 Second drawing roll 22 Relaxing roll 23 Winding machine 24 Spinneret pack

Claims (4)

Spinning as a melted polyethylene terephthalate polyester yarn, heating the yarn immediately after spinning, cooling and solidifying it to obtain an undrawn yarn, and winding the obtained undrawn yarn once In the method for producing a polyester fiber for industrial materials in which the stretched yarn immediately after stretching is taken up at a speed of 4000 m / min or more, and finally the drawn yarn is finally wound,
With respect to the drawing roll group used when the undrawn yarn is subjected to heat drawing treatment, at least a part or the entire surface of the yarn contact surface on the base material of the final drawing roll is subjected to roughening treatment and then hard chrome plating. And adopting a drawing roll having a diamond-like carbon coating film formed by a plasma-based ion implantation / film-forming method by finishing the surface of the satin surface having a spherical surface with a convex portion of the contact surface. A manufacturing method of polyester fiber for industrial materials.   The industrial material according to claim 1, wherein a stretching roll having a thickness of the hard chrome plating of 10 to 100 µm and a thickness of the diamond-like carbon coating film of 2 to 50 µm is used. Of producing polyester fiber for use in a process.   The method for producing polyester fibers for industrial materials according to claim 1 or 2, wherein the diamond-like carbon coating film has a Pickers hardness of 1000 to 4000 Hv.   The method for producing a polyester fiber for industrial materials according to any one of claims 1 to 3, wherein the finally wound polyester fiber is used for a seat belt.