JP2009030225A - Continuous drying apparatus for head decorating regenerated collagen fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method and a continuous drying apparatus for head-decorating regenerated collagen fiber, capable of preventing occurrence of fluff (fiber breakage) to prevent a process trouble, having excellent curl retentive properties, and having less hackling loss. <P>SOLUTION: In the method and apparatus, fiber bundles 1 led into a drying chamber are twisted and drive rolls 4 and 8 are installed at an inlet and an outlet, either of the drive roller at the inlet and outlet is rotated at a constant speed, the fiber tension is detected by a tension detector 5 installed on a drying chamber 7 side of the outlet drive roll, a mechanism is provided to be for controlled so that a rotational speed of the other drive roll so that the outlet tension gives a desired value, free rolls 6 are installed between the inlet and the outlet at predetermined intervals so that the tension of the fiber bundles during drying is lower than that of outlet tension and the difference of the tension between the inlet and the outlet is reduced. Continuous drying is carried out while controlling the tension of the fiber bundle during drying by using the drying apparatus in which these freely rotatable rolls are installed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is characterized in that, in the production of regenerated collagen fibers for head ornaments such as wigs and hair accessories, the fiber bundle is twisted, and the tension of the fiber bundle during drying is controlled to a desired value. The present invention relates to an apparatus for continuously drying regenerated collagen fibers that prevent occurrence of yarn breakage, have excellent curl setting properties, and have little hackling loss.

  Regenerated collagen fiber is generally manufactured by a method in which animal skin and bone are used as raw materials, and this is subjected to alkali or enzyme treatment to decompose and remove the telopeptide part of collagen to form water-soluble collagen, which is then spun. Is done. Further, the spun fiber is subjected to various treatments depending on its use. As an example, a process combining two methods using a monofunctional epoxy compound and an aluminum salt is applied to collagen (Patent Document 1), and after that process, a drying process is performed to remove moisture contained in the fibers. Applied.

  Regenerated collagen fibers are very weak in tensile strength of the hydrated yarn before drying, and yarn breakage (fluff) is likely to occur during drying. The shrinkage behavior of this material changes greatly depending on the drying conditions. Furthermore, if there is a fear of thread breakage but the tension during drying is reduced too much, the shrinkage rate of the regenerated collagen fiber at the end of drying increases, and the curl setting that is one of the important qualities of the head decoration fiber does not appear, There is a problem that the value of the product decreases.

  As a drying method for regenerated collagen fibers, with respect to batch-type drying conditions, the drying temperature is 100 ° C. or lower, further 75 ° C. or lower, and the load is 0.01 to 0.25 g weight per 1 dtex, particularly 0.02 It is disclosed that it is preferable to dry under a gravity of ˜0.15 g (Patent Document 1). However, from the viewpoint of improving productivity, it is indispensable to develop a continuous drying method and an apparatus therefor, but problems such as generation of fluff (thread breakage) and tension control of fibers traveling in the dryer are listed. However, continuous drying of regenerated collagen fibers is not in practical use.

  Regarding the production of general synthetic fibers such as acrylic and amide fibers, unlike regenerated collagen fibers, these fibers can be stretched during drying and heat treatment, so hot air drying methods and heat rolls using multiple drive rolls. A general-purpose dryer of the type is used, and in order to adjust the fineness or to improve the quality such as strength, the drive roll The current situation is that the rotation speed is gradually increased as it approaches the exit of the process, and the film is dried while being stretched. In contrast, regenerated collagen fibers cannot be stretched when dried. If it is forcibly stretched, the fiber bundle breaks, resulting in process trouble. Furthermore, if it is continuously stretched without being stretched, dry spots are formed on the fiber bundle being dried, a difference occurs in the contraction length of the fiber, and drooping occurs in the latter half of the drying. Wrap around or roll off. As a result, it causes thread breakage or fiber bundle breakage, resulting in a situation where it cannot be operated.

  On the other hand, there are several prior literatures regarding methods and apparatuses for continuous drying while maintaining a constant tension. For example, for the purpose of improving the dimensional stability of copper ammonia rayon fiber, there is disclosed an apparatus in which a plurality of dryers are provided and a plurality of driving rolls (yarn feeders) are installed between them in order to maintain low tension ( Patent Document 2). However, when this apparatus is used for drying the regenerated collagen fibers, it is difficult to keep the fiber tension between the driving rolls constant. This is because when the regenerated collagen fiber is dried, it rapidly shrinks in the vicinity of the reduced rate drying zone, and when the drying conditions change, the shrinkage behavior of the fiber changes greatly. This is because it cannot be specified at a certain position in the dryer and the position moves in the dryer. Therefore, it is extremely difficult to match the shrinkage behavior of the fiber with the reduction ratio of the drive roll, and a section where the fiber tension is high and a section where the fiber tension is high are formed, and yarn breakage (fluff) occurs in the section where the fiber tension is high. In the lower section, thread dripping occurs, which leads to process trouble.

  In addition, there is a document that describes the use of a plurality of Nelson rollers and tapered rollers as a method for drying by applying a constant tension for the purpose of producing high modulus type PPTA fibers with less fluff (Patent Document 3). ). However, even when this device is used for drying regenerated collagen fibers, for the reasons described above, it is difficult to match the relaxation angle of the Nelson roller or tapered roller with the contraction behavior of the fibers, and the yarn is used at a place where the fiber tension becomes high. Cuts (fluff) occur, and thread dripping occurs at a location where the fiber tension is low.

  Furthermore, with the aim of producing high modulus fibers with excellent wear resistance, one method of drying under constant tension was described as passing the yarn over a heated roll (heat roll) and between rolls. There is literature (Patent Literature 4). However, when this heat roll is employed for drying the regenerated collagen fiber, with a normal straight copper type heat roll, the drying proceeds and the yarn shrinks and the tension continues to rise. As a result, the tension cannot be controlled, and the fiber bundle (tow) cannot be broken. Therefore, in the case of a regenerated collagen fiber, continuous drying operation with a heat roll alone cannot be performed.

  In addition, for the purpose of producing hollow fibers for cellulosic blood treatment that shrink slightly when wet, the method of drying while controlling the tensile tension was found to control the rotation speed of the yarn introduction roller. (Patent Document 5). A feature of this apparatus is that it has a structure in which a drive roll (a yarn introduction roller and a take-up roller) is installed at the entrance of the dryer, and is a one-pass dryer in which no roll exists in the dryer. Here, when drying the regenerated collagen fiber, if the dwelling length of the dryer is calculated from the viewpoints of operating conditions considering quality (drying time 30 minutes or more) and productivity (processing speed 3 m / minute or more), at least 90 m or more is required. It becomes. Therefore, it is extremely difficult to realize a one-pass dryer of 90 m or more in consideration of location conditions, construction costs, operability, etc., regardless of whether it is a horizontal type or a vertical type. It is not practical to employ a machine for drying regenerated collagen fibers.

From the above, in the production of regenerated collagen fibers for head ornaments, a method and apparatus for continuously drying regenerated collagen fibers having excellent quality without causing any process trouble have not yet been found.
WO02 / 52099 JP-A-48-22710 JP-A-60-88117 JP-A-4-214434 JP 57-14359 A

  The object of the present invention is to be able to produce high quality regenerated collagen fibers for head ornaments without causing process troubles even if the shrinkage behavior of the regenerated collagen fibers changes due to drying under different conditions such as temperature and humidity. To develop a continuous drying method and apparatus.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, the fiber bundle introduced into the drying chamber is twisted at a predetermined ratio, and the tension of the fiber bundle being dried is controlled within a certain range. As a result, it was found that continuous drying of the regenerated collagen fibers was possible by drying, and the present invention was completed.

  That is, in the present invention, the fiber bundle introduced into the drying chamber is twisted, and the fiber bundle being dried is controlled to be in the range of 0.01 to 0.08 gf / dtex and continuously dried. It is related with the manufacturing method of the reproduction | regeneration collagen fiber for head decoration characterized by doing. Here, it is preferable that the number of twists put in the fiber bundle is 0.2 to 5 / m. Furthermore, at this time, it is preferable to control the value of the tension at the outlet side of the drying chamber within a range of 0.02 to 0.08 gf / dtex.

  Furthermore, the present invention installs a driving roll at the entrance / exit of the drying chamber, rotates one of the entrance / exit driving rolls at a constant speed, and detects the fiber tension from the tension detector installed on the drying chamber side of the exit driving roll. And a mechanism for controlling the rotational speed of the other drive roll so that the exit tension becomes a desired value, and a freely rotating free roll for reciprocating the fiber bundle at least once in the drying chamber is provided at the exit from the entrance. It is related with the continuous drying apparatus characterized by being installed at predetermined intervals between.

  As described above, with the continuous drying method and apparatus of the present invention, in the production of regenerated collagen fibers for head ornaments, the occurrence of fluff (thread breakage) is prevented to prevent process troubles, and curl setability is excellent and hackling loss is achieved. Realized the continuous production of regenerated collagen fibers with low content.

  The present invention is described in further detail below. The regenerated collagen fiber for head decorations that is the subject of the present invention is appropriately treated with, for example, sodium hydroxide, boric acid, sodium hydrogen carbonate, sodium lactate, disodium hydrogen phosphate after acid treatment of solubilized collagen as necessary. Mono-functional epoxy compounds, aluminum salts, etc. produced by discharging fibers into an aqueous solution containing one or more inorganic salts such as sodium sulfate, sodium chloride, ammonium sulfate, etc., adjusted for pH, through a spinning nozzle or slit Regenerated collagen fibers (see Patent Document 1) obtained by treating with water to make them water resistant can be used, but can also be applied to other regenerated collagen fibers for head ornaments.

  Here, the properties of the regenerated collagen fiber will be described. FIG. 1 shows an example of the shrinkage behavior of regenerated collagen fibers during batch drying. As can be seen from FIG. 1, the regenerated collagen fiber contracts rapidly in the vicinity of entering the reduced rate drying region, that is, in the vicinity where the water content of the fiber is reduced to 50 to 70 wt% -drybase. Therefore, in the continuous drying, the contraction rate of the regenerated collagen fiber is different at each position in the continuous drying apparatus. In addition, since the shrinkage behavior varies greatly depending on the drying conditions, the position where the fiber shrinks moves in the drying device depending on the drying conditions. Furthermore, the regenerated collagen fiber shrinks when dried, but cannot be stretched, and has the property of being cut if it is forced to stretch. Therefore, if there is a fear of thread breakage but if the tension during drying is too low, the shrinkage of the product after drying will increase, and the curl setting, which is one of the important qualities of the head decoration fiber, will not be manifested. There is a problem of loss of value. Furthermore, if the fiber bundle is continuously dried as it is, thread dripping occurs in the latter half of the drying due to dry spots, and the drooped thread wraps around the roll or comes off the roll, resulting in yarn breakage or tow (fiber bundle ) There is a problem that causes cutting. The dry spots referred to here is a phenomenon that the fibers located on the surface of the fiber bundle dries and shrinks faster than the fibers located in the center. When dry spots occur, only the fibers on the contracted fiber bundle surface will support the tension of the entire fiber bundle. Become. As a result, the shrinkage rate of the quickly dried fiber is reduced, and the fiber length becomes longer in the latter half of the drying compared to the fiber at the center of the fiber bundle. In the case of a yarn that can be drawn like a general chemical fiber, dripping can be prevented if it is gradually drawn during drying, but in the case of a regenerated collagen fiber, it cannot be drawn because it cannot be drawn.

  In the present invention, when the regenerated collagen fiber having such properties is continuously dried, the above problem is solved by twisting the fiber bundle introduced into the drying chamber and controlling the tension of the fiber bundle being dried. In the present invention, the amount of fiber bundles during drying is preferably 5000 filaments or less. When it is more than that, the fiber bundle becomes thick, and the dry spots between the surface portion and the center portion of the fiber bundle tend to be too large.

  In the present invention, the method for putting a certain number of twists into the fiber bundle is not particularly limited, but the method of putting the fiber bundle into the container at a constant speed while rotating the container at a constant speed, There is a method of introducing the fiber bundle into the dryer while rotating the container at a constant speed, and any method may be adopted. The preferred number of twists for drying is 0.2 pieces / m to 5 pieces / m. When the number of twists in the fiber bundle is less than 0.2 pieces / m, the convergence of the fiber bundle is deteriorated, and it is difficult to sufficiently suppress the thread droop caused by dry spots, resulting in yarn breakage and process trouble. May be caused. On the other hand, when the number of twists is more than 5 / m, it is good in terms of improving the convergence of the fiber bundle and preventing drooping, but the twisted shape tends to remain on the dried yarn, making it difficult to use in straight applications There is.

  Furthermore, in the present invention, it is necessary to perform drying while controlling the tension of the fiber bundle during drying to be in the range of 0.01 to 0.08 gf / dtex throughout. When the tension of some fiber bundles during drying is less than 0.01 g weight / dtex, the fiber bundles droop or droop at that part, and the drooped yarn may wrap around the roll or come off the roll. It causes process trouble. Furthermore, the quality of the regenerated collagen fiber after drying, particularly curl setting, is also adversely affected. In addition, when the tension of a part of the fiber bundle during drying exceeds 0.08 gf / dtex, a load is applied to the part and thread breakage occurs.

  In the present invention, the method for controlling the tension of the fiber bundle at the time of drying to be within the range of 0.01 to 0.08 gf / dtex is not particularly limited, and any method can be used. When a continuous drying device combining a combination of a driving roll and a free roll is used, the tension value of the fiber bundle in the dryer gradually increases from the dryer inlet to the outlet. Therefore, it is a preferable method because the tension of the fiber bundle in the entire dryer can be set to a desired value only by controlling the tension value at the outlet of the dryer using the driving roll. Hereinafter, a preferable continuous drying apparatus used in the production method of the present invention and a method using the same will be described.

In FIG. 2, the outline of the preferable continuous drying apparatus of this invention is shown. Drive rolls 4 and 8 are installed on the inlet side and the outlet side of the drying chamber 7. The drive roll may be any roll that can freely control the feeding speed of the fiber bundle depending on the rotational speed thereof, and preferably capable of suppressing the sliding of the fiber bundle and further capable of preventing the sliding of the fiber bundle.
That is, it may be a multiple roll that prevents slippage by utilizing friction between the fiber and the roll surface, or a nip roll having a structure in which a roll with rubber is pressed against a metal roll. Multiple rolls and nip rolls may be used in combination.

  Between the entrance and the exit of the drying chamber 7, freely rotating free rolls 6 are installed at predetermined intervals. The free roll here is defined as one having a small frictional resistance when rotated. Generally, the tension of the fiber bundle gradually attenuates as it goes from the outlet of the drying chamber to the inlet, but the amount of attenuation of the tension is determined by the magnitude of the frictional resistance of the bearing that constitutes the free roll. The free roll used in the present invention preferably has a tension attenuation amount represented by (damping tension per free roll) × (number of free rolls) of 0.03 gf / dtex or less. Here, in place of the free roll, when a driving roll used for drying general fibers is installed, the tension rises and fluff (thread breakage) occurs in a section where the fibers contract significantly. Furthermore, if the drying conditions are changed, the shrinkage behavior of the fiber changes greatly, and the position where the fiber shrinks moves in the drying chamber. Therefore, the reduction ratio of the drive roll installed in the drying chamber is matched to the shrinkage behavior of the fiber. It becomes extremely difficult to keep the fiber tension in the drying chamber uniform. However, if a free roll that rotates freely as in the present invention is installed, the tension is dispersed regardless of the position where the fiber contracts from the inlet to the outlet, so that the fiber tension inside the dryer is lower than the outlet tension. In addition, the tension difference between the entrance and exit can be reduced.

  In the present invention, the rotational speed of one of the drive rolls at the entrance / exit is made constant, a signal is detected from the tension detector 5 installed on the drying chamber side of the exit drive roll, and the rotational speed of the other drive roll is The tension of the entire fiber bundle being dried can be controlled by drying while controlling the outlet side tension value to be constant. The tension control method may be a general method such as PID control. The PID control is one of control operations performed by the control device in the automatic control system, and is a combination of proportional operation, integration operation, and differentiation operation.

  In the present invention, the drying chamber outlet tension is controlled within the range of 0.02 to 0.08 gf / dtex from the viewpoint of the number of fluff (number of yarn breaks) at the end of drying, the amount of hackling loss, and curl setting. Is preferred. When the outlet tension is controlled to be higher than 0.08 gf / dtex, fluff (thread breakage) occurs, causing a process trouble and increasing the amount of hackling loss. On the other hand, when the outlet tension of the drying chamber is controlled to be lower than 0.02 g weight / dtex, the curl setting property, which is one of the important qualities of the head decoration fiber, is not exhibited. Moreover, when the free roll which becomes said preferable tension | tensile_strength amount is installed by controlling the value of drying chamber exit tension within the range of 0.02-0.08g weight / dtex, the tension | tensile_strength of the fiber bundle at the time of drying is set. It can be in the range of 0.01 to 0.08 gf / dtex throughout.

  Regarding the temperature condition during continuous drying, the higher the temperature, the larger the drying spots between the fiber bundle surface and the inside, and therefore, it is preferable to dry at 100 ° C. or lower, more preferably 80 ° C. or lower. The lower limit of the temperature condition is not particularly limited, but it goes without saying that if it is too low, it takes time for drying.

  As described above, the present invention is characterized in that the fiber tension during drying can be controlled to a desired value even if the shrinkage behavior of the regenerated collagen fiber changes after drying under different conditions such as temperature and humidity. If the fiber tension is controlled in this manner, the tension of the fiber bundle traveling in the drying chamber can be lower than the tension at the outlet of the drying chamber, and the tension difference between the inlet and outlet can be reduced. As a result, the fluff (thread breakage) can be reduced. It can prevent the occurrence of process trouble by preventing the occurrence, and can realize the continuous production of regenerated collagen fibers for head ornaments with excellent curl setting and little hackling loss.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. Tables 1 and 2 summarize the relationship between the drying conditions and the number of fluff (number of yarn breaks), the hackling loss rate, and the curl setting property in Examples and Comparative Examples.
FIG. 3 shows the tension fluctuation of the fiber bundle in the drying apparatus (during drying) in that example. The regenerated collagen fiber used for drying was produced according to the method described in Patent Document 1. Prior to describing the examples, measurement and evaluation methods of fiber shrinkage, curl setting, number of fluff (number of yarn breaks), and hackling loss rate will be described.

(Fiber shrinkage)
The fiber length L ₀ per unit time introduced at the drying inlet and the fiber length L ₁ per unit time coming out from the drying outlet were measured, and the fiber shrinkage was calculated by the following equation.

Fiber shrinkage (%) = (L ₀ −L ₁ ) / L ₀ × 100

(Curl setting)
Evaluation of curling shape imparting and curl set retention was performed as follows.

  (1) A sewing machine was applied to the center of a well-opened fiber bundle (6.3 g / 58.4 cm) to form eyelashes having a fiber length of 33 cm and a width of 12 cm.

  (2) The eyelashes were left standing in an atmosphere of 25 ° C. and 80% RH for 12 hours or longer.

  (3) The eyelashes were folded into four to a width of 3 cm and wound around an aluminum pipe with an outer diameter of 12 mm with one twist per pitch, and both ends were firmly fixed with rubber bands so that the fiber bundle did not shift.

  (4) The rod after winding was put into a steam setter (manufactured by Hirayama Seisakusho: HA-300P), and the eyelashes were wetted at 80 ° C. for 4 hours. Then, it was immersed in a silicon-based oil solution (0.44 wt%) for 5 minutes, dried with a hot air convection dryer (manufactured by Tabay Espec Co., Ltd .: PV-221) for 1 hour at 90 ° C., and allowed to cool for 30 minutes.

  (5) The eyelashes were removed from the aluminum pipe, and the eyelashes were loosened in an aqueous silicone oil solution (0.44 wt%), and the curled shape was adjusted on a net. Then, it dried at 50 degreeC with the hot air convection type dryer for 2 hours.

(6) The eyelashes were shampooed according to the following procedure.
1) Take 1/2 pump amount of shampoo agent (manufactured by Shiseido Co., Ltd .: Super Mild Shampoo Floral Fruity) in your hand.

    2) Apply shampoo to eyelashes and wash by hand ten times.

    3) Rinse with warm water of 40 ° C.

    4) Squeeze the eyelashes and squeeze the water.

    5) Hang the eyelashes and pass the hand comb 10 times.

    6) Again, firmly grasp the base, middle and tip of the eyelashes.

    7) Put the eyelashes in the towel and absorb moisture.

    8) Pass the hand comb through the eyelashes three times.

    9) Suspend the eyelashes at 50 ° C for 90 minutes to dry.

  (7) Curl-shaped shampoo resistance (curl shape retention by repeated shampooing) is repeated three times to observe whether the curl shape is retained, and provides good curl shape retention. What was shown was marked with ◯, those with a slight curl shape falling, and those with little curl shape observed.

(Number of fuzz (number of yarn breaks))
At the outlet of the drying chamber, the number of yarn breaks present per 72 m fiber bundle of 700 filaments was visually measured. 36 or less were accepted.

(Hackling loss rate)
Fabricate a fiber bundle of 70cm 44800 filaments, leave it in an environment of temperature 20 ± 2 ° C and humidity 65 ± 2% RH for 8 hours, then hackling 50 times from one side and 50 times from the other side for a total of 100 times. From the previous weight W ₀ and the weight W ₁ after hackling, the hackling loss rate was calculated by the following formula. 1.0% or less was regarded as acceptable.

Hackling loss rate (%) = (W ₀ −W ₁ ) / W ₀ × 100
Example 1
In FIG. 2, the schematic of the drying apparatus used in the Example is shown. 23 free rolls 6 (bearing: product name 6005ZE C3 NACHI) having a roll diameter of 140 mm, a roll length of 500 mm, and a shaft diameter of 25 mm are installed in the drying chamber 7 at intervals of 6 m, and the residence length is 144 m (6 m × 24 passes). did. Driving rolls 4 and 8 using a combination of multiple rolls and nip rolls were installed at the entrance and exit of the drying chamber to prevent slippage of the fiber bundle, and hot air at a constant wind speed was blown into the drying chamber. Also, a tension detector 5 (LX-TD type tension detector: Mitsubishi Electric Corporation) is installed in the vicinity of the entrance / exit of the drying chamber, a signal is taken out from the outlet side tension detector, and the tension value on the outlet side becomes constant. The rotational speed of the outlet drive roll was PID controlled. The drying conditions were a temperature of 65 ° C., and the outlet side tension was controlled to 0.036 g weight / dtex (20 N / 700 f). The inlet side tension at that time was 0.018 gf / dtex (10 N / 700 f).

  As shown in FIG. 3, the tension gradually attenuates from the outlet toward the inlet, and this is due to the frictional resistance of the bearing generated when the free roll rotates. Four 700 filament fiber bundles were introduced into the drying apparatus, and each fiber bundle was twisted at a rate of 0.5 pieces / m. The fineness of the single fiber was 80 dtex, the fineness of the fiber bundle was 56000 dtex, and the total fineness was 224,000 dtex.

  The shrinkage rate of regenerated collagen fibers dried under the above conditions is 7%, the number of fluff (thread breakage) at the drying chamber outlet is 8 / 700f x 72m, the hackling loss rate is 0.1%, and both evaluations pass. The standard was cleared and the curl setting property was also good (see Table 1).

(Example 2)
The experiment was performed in the same manner as in Example 1 except that the number of twists was 0.5 / m. As a result, the fiber shrinkage rate was 7%, the number of fuzz (thread breakage) and the hackling loss rate both passed the acceptance criteria, and the curl setting property was also good.

(Example 3)
An experiment was conducted in the same manner as in Example 1 except that the number of twists was 0.5 / m. As a result, the fiber shrinkage rate was 7%. Compared to Example 1, the convergence of the fiber bundle was poor and the number of fluff (thread breakage) was 30, and the hackling loss rate was increased to 0.3%. The curl setting was also good.

Example 4
The experiment was performed in the same manner as in Example 1 except that the drying temperature was changed to 65 ° C. As a result, the fiber shrinkage rate was 5%. Both the number of fluff (thread breakage) and the hackling loss rate cleared the acceptance criteria, and the curl setting was also good.

(Example 5)
The experiment was performed in the same manner as in Example 1 except that the drying temperature was changed to 65 ° C. As a result, the fiber shrinkage rate was 8%. Both the number of fluff (thread breakage) and the hackling loss rate cleared the acceptance criteria, and the curl setting was also good.

(Example 6)
The experiment was conducted in the same manner as in Example 1 except that the outlet side tension was 0.036 g weight / dtex (20 N / 700 f) and 0.054 g weight / dtex (30 N / 700 f). As a result, the inlet side tension was 0.034 g weight / dtex (19 N / 700 f), and the tension gradually decreased from the outlet toward the inlet as shown in FIG. The fiber shrinkage rate was 6%. Both the number of fluff (thread breakage) and the hackling loss rate cleared the acceptance criteria, and the curl setting was also good.

(Example 7)
The experiment was performed in the same manner as in Example 1 except that the outlet side tension was 0.036 g weight / dtex (20 N / 700 f) was changed to 0.071 g weight / dtex (40 N / 700 f). As a result, the inlet side tension was 0.050 g weight / dtex (28 N / 700 f), and the tension gradually decreased from the outlet toward the inlet. The fiber shrinkage was 4%. Compared to Example 1, the number of fluffs (yarn breaks) increased to 33 and the hackling loss rate increased to 0.4% due to higher fiber tension, but both passed and passed the pass criteria. The curl setting property was also good.

(Example 8)
The experiment was performed in the same manner as in Example 1 except that one fiber bundle of 2800 filaments was introduced into the drying apparatus. As a result, the dry spots became larger and the convergence of the fiber bundle was slightly reduced, and the number of fluff (thread breakage) and hackling loss rate increased from Example 1, but both evaluations passed the acceptance criteria, The curl setting property was also good.

Example 9
The experiment was performed in the same manner as in Example 1 except that the rotational speed of the inlet drive roll was PID controlled so that the tension value on the outlet side was constant. As a result, the fiber shrinkage rate was 7%, the number of fuzz (thread breakage) and the hackling loss rate both passed the acceptance criteria, and the curl setting property was also good.

(Comparative Example 1)
The experiment was performed in the same manner as in Example 1 except that the number of twists was 0.5 pieces / m and was 0 pieces / m (no twist). As a result, in Example 1, no thread dripping occurred, but in Comparative Example 1, thread dripping occurred in the latter half of drying, and the drooped thread wound around the roll or detached from the roll, causing thread breakage, The fiber bundle (tow) broke along the way, and the operation was stopped. In the evaluation conducted until the fiber bundle broke, the number of fluffs (thread breakage) at the drying outlet was about 200/700 f × 72 m, and the hackling loss rate was 5.2%, which did not reach the acceptance standard.

(Example 10)
The experiment was performed in the same manner as in Example 1 except that the number of twists was 0.5 pieces / m and 0.17 pieces / m. As a result, some dripping occurred in the latter half of the drying, and some thread breakage occurred. However, it was milder than Comparative Example 1, and continuous operation was possible.

(Example 11)
The experiment was performed in the same manner as in Example 1 except that the number of twists was 0.5 / m. As a result, the convergence property of the fiber bundle was high, the pass standard was satisfied for both the number of fuzz and the hackling loss rate, and the curl setting property was also good. However, since the number of twists was large, some twisted shapes remained in the obtained dried yarn.

(Comparative Example 2)
The experiment was conducted in the same manner as in Example 1 except that the outlet side tension was 0.036 g weight / dtex (20 N / 700 f) and 0.018 g weight / dtex (10 N / 700 f). As a result, the inlet side tension was 0.005 gf / dtex (3N / 700f), and the tension was gradually attenuated from the outlet toward the inlet as shown in FIG. The fiber shrinkage was as high as 11%. Because the tension was low, both the number of fluff (thread breakage) and hackling loss rate passed the acceptance criteria. However, the curl set retention was deteriorated due to the higher shrinkage during drying.

(Comparative Example 3)
The experiment was performed in the same manner as in Example 1 except that the outlet side tension was 0.036 g weight / dtex (20 N / 700 f) and 0.089 g weight / dtex (50 N / 700 f). As a result, the inlet side tension was as high as 0.066 g weight / dtex (37 N / 700 f) (see FIG. 3), and the fiber shrinkage rate was as low as 2%. The number of fluff (thread breakage) at the drying outlet was about 150/700 f × 72 m, and the hackling loss rate was 4.0%, which did not reach the acceptance standard.

(Comparative Example 4)
FIG. 4 shows a schematic diagram of a Nelson dryer. The experiment was conducted by connecting three Nelson dryers 10, 11, and 12 using a tapered roll 9 having a roll diameter of 125 mm and a length of 625 mm. The distance between the rolls in each dryer was 800 mm, and the tow (fiber bundle) was retained for 7.5 turns, and dried by blowing hot air at a constant speed. As for the Nelson roll 9 of each dryer, those having a taper angle adjusted so that the shrinkage rate was 2.4% were used for all three machines. Therefore, the shrinkage ratio of the fibers at the drying outlet connected to the three machines is 7.0%. The drying temperature was 65 ° C. The fiber bundle introduced into the dryer was 700 filaments, and the fiber bundle was twisted at a rate of 0.5 pieces / m. The fineness of the single fiber was 80 dtex, and the fineness of the fiber bundle was 56000 dtex.

  As shown in FIG. 3, the tension in the dryer rapidly increased to 0.214 g weight / dtex (120 N / 700 f) at a position where the fiber entered the reduced rate drying region and the fiber contracted significantly. As a result, although the shrinkage ratio of the fiber at the drying outlet was 7%, which was the same as in Example 1, yarn breakage occurred in the dryer, and the number of fluff was about 300/700 f × 72 m, and the hackling loss rate Was 7.8% and did not meet the acceptance criteria. In addition, the appearance of the tow (fiber bundle) was poor and there was no commercial value.

(Comparative Example 5)
The experiment was conducted by changing the free roll of the drying apparatus shown in FIG. 2 to a drive roll. About the rotational speed of each drive roll, it adjusted so that the shrinkage | contraction rate of the fiber of a drying exit might be 7.0%, ie, the rotational speed of the exit drive roll might be 93% of the inlet drive roll speed. Moreover, the speed of the drive roll in the drying chamber gradually decreased evenly as it approached the outlet from the drying inlet. The drying temperature was 65 ° C. Four 700 filament fiber bundles were introduced into the drying apparatus, and each fiber bundle was twisted at a rate of 0.5 pieces / m. The fineness of the single fiber was 80 dtex, the fineness of the fiber bundle was 56000 dtex, and the total fineness was 224,000 dtex.

  As a result, the tension fluctuation in the drying apparatus behaved in substantially the same manner as in Comparative Example 4, and the tension value increased to a maximum of 0.205 gf / dtex (115 N / 700 f). As a result, the fiber shrinkage at the outlet of the drying chamber was 7%, the same as in Example 1, but yarn breakage occurred in the drying chamber and the number of fluffs was about 300/700 f × 72 m, hackling loss. The rate was very high at 7.4% and did not meet the acceptance criteria. In addition, the appearance of the tow (fiber bundle) was poor and there was no commercial value.

(Comparative Example 6)
In FIG. 5, the schematic of a heat roll dryer is shown. The experiment was conducted using a dryer composed of 12 heat rolls having a roll diameter of 565 mm and a width of 500 mm. The tow (fiber bundle) was returned from the outlet side to the inlet side heat roll 13 via the guide roll 14, and the angle of the guide roll was adjusted to make 12 turns on the heat roll. The heat roll was a straight cylinder, the driving speed of each heat roll was constant, and the shrinkage of the fiber during drying was 0%. The drying temperature was 60 to 70 ° C. The fiber bundle introduced into the dryer was 700 filaments, and the fiber bundle was twisted at a rate of 0.5 pieces / m. The fineness of the single fiber was 80 dtex, and the fineness of the fiber bundle was 56000 dtex.

  As a result, the tension became 0.214 g weight / dtex (120 N / 700 f) or more during drying, and the tow (fiber bundle) broke, making it impossible to continue the operation.

Temporal changes in fiber shrinkage and moisture content during batch drying (fiber shrinkage behavior) Schematic of a free roll type drying apparatus (Examples 1-11, Comparative Examples 1-3) Tension fluctuation of fiber bundle in drying device (during drying) Schematic of Nelson dryer connected to 3 machines (Comparative Example 4) Schematic of heat roll dryer (Comparative Example 6)

Explanation of symbols

1 Fiber bundle (tow)
2 Roller pump 3 Oil tank 4 Drying inlet drive roll 5 Tension detector 6 Free roll 7 Drying chamber 8 Drying exit drive roll 9 Nelson roll (drive)
10 Nelson dryer 1
11 Nelson dryer 2
12 Nelson dryer 3
13 Heat roll (drive)
14 Guide roll

Claims (1)

  A drive roll is installed at the entrance and exit of the drying chamber, a tension detector is installed on the drying chamber side of the exit drive roll, and the rotation speed of the drive roll is adjusted so that the drying chamber exit tension detected from the tension detector becomes a desired value. A continuous roll characterized in that it has a control mechanism, and a freely rotating free roll for reciprocating the fiber bundle at least once in the drying chamber is installed between the inlet and the outlet. Drying equipment.

Images