Cellulose acetate tow band and method for producing cellulose acetate tow band
阅读说明：本技术 乙酸纤维素丝束带及乙酸纤维素丝束带的制造方法 (Cellulose acetate tow band and method for producing cellulose acetate tow band ) 是由 小国数马 于 2017-11-22 设计创作，主要内容包括：本发明要解决的课题是通过防止对乙酸纤维素纤维进行纺丝时的断丝,从而使得提高乙酸纤维素丝束带的制造效率成为可能。本发明的乙酸纤维素丝束带为由乙酸纤维素纤维构成的丝束带,其总旦数被设定为8000以上且44000以下的范围的值,二氧化钛含量被设定为0重量％以上且0.01重量％以下的范围的值,丝束带的由乙醚提取法测得的纤维油剂的含量被设定为相对每1m而言大于5mg且为65mg以下的范围的值。(The invention aims to prevent the breakage of cellulose acetate fibers during spinning, thereby improving the production efficiency of cellulose acetate tow bands. The cellulose acetate tow band of the present invention is a tow band composed of cellulose acetate fibers, the total denier of which is set to a value in the range of 8000 or more and 44000 or less, the titanium dioxide content is set to a value in the range of 0% by weight or more and 0.01% by weight or less, and the content of a fiber finish measured by an ether extraction method of the tow band is set to a value in the range of more than 5mg and 65mg or less per 1 m.)
1. A cellulose acetate tow band which is a tow band composed of cellulose acetate fibers,
the total denier thereof is set to a value in the range of 8000 or more and 44000 or less, the titania content is set to a value in the range of 0 wt% or more and 0.01 wt% or less, and the content of the fiber finish of the tow band measured by ether extraction is set to a value in the range of more than 5mg and 65mg or less per 1 m.
2. The cellulose acetate tow band according to claim 1, wherein the denier per filament is set to a value in the range of 1.0 or more and 12.0 or less.
3. The cellulose acetate tow band according to claim 1 or 2, wherein the denier per filament is set to a value in the range of 1.0 or more and less than 5.0,
the cellulose acetate fiber is crimped, and the crimp percentage (%) of the tow band calculated by formula 1 is set to a value in the range of 10% to 40%,
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when the tow band having a length of 250mm is loaded with a load of 250g in a direction that straightens the crimp of the cellulose acetate fiber; l1 is the length of the tow band when loaded with 2500g of load along the direction for the tow band having a length of 250 mm.
4. The cellulose acetate tow band according to claim 1 or 2, wherein the denier per filament is set to a value in the range of 5.0 or more and 9.0 or less, the total denier is set to a value in the range of 15000 or more and 20000 or less, the content of the fiber finish measured by ether extraction of the tow band is set to a value in the range of 10mg or more and 30mg or less per 1m,
the cellulose acetate fiber is crimped, and the crimp percentage (%) of the tow band calculated by formula 1 is set to a value in the range of 10% to 30%,
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when the tow band having a length of 250mm is loaded with a load of 250g in a direction that straightens the crimp of the cellulose acetate fiber; l1 is the length of the tow band when loaded with 2500g of load along the direction for the tow band having a length of 250 mm.
5. A method for producing a cellulose acetate tow band, comprising the steps of:
a spinning dope preparation step in which a spinning dope is prepared;
a spinning step in which a plurality of cellulose acetate fibers are spun using the spinning dope so that the total denier of the manufactured tow band is set to a value in the range of 8000 or more and 44000 or less; and
an addition step of adding a fiber finish to the cellulose acetate fiber so that the fiber finish content of the produced tow band measured by an ether extraction method is set to a value in a range of more than 5mg and 65mg or less per 1 m;
in the spinning dope preparation step, the spinning dope is prepared so that the titania content of the produced tow band is set to a value in the range of 0 wt% to 0.01 wt%.
6. The method for producing a cellulose acetate tow band according to claim 5, wherein the cellulose acetate fibers having a denier per filament set to a value in the range of 1.0 to 12.0 are spun in the spinning step.
7. The method for producing a cellulose acetate tow band according to claim 5 or 6, further comprising a crimping step in which the cellulose acetate fiber is crimped so that a crimp percentage (%) of the tow band after production, which is calculated by the formula 1, is set to a value in a range of 10% to 40%,
in the spinning step, the cellulose acetate fiber having a denier per filament set to a value in the range of 1.0 or more and less than 5.0 is spun,
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when the manufactured tow band having a length of 250mm is loaded with a load of 250g in a direction to straighten the crimp of the cellulose acetate fiber; l1 is the length of the tow band when loaded with 2500g of load along the direction against the manufactured tow band having a length of 250 mm.
8. The method for producing a cellulose acetate tow band according to claim 5 or 6, further comprising a crimping step in which the cellulose acetate fiber is crimped so that a crimp percentage (%) of the tow band after production, which is calculated by the formula 1, is set to a value in a range of 10% to 30%,
in the spinning step, the plurality of cellulose acetate fibers are spun so that the produced tow band has a denier per filament in the range of 5.0 to 9.0 inclusive and a total denier in the range of 15000 to 20000 inclusive,
in the attaching step, a fiber finish is attached to the cellulose acetate fiber so that the content of the fiber finish measured by an ether extraction method in the tow band is set to a value in a range of 10mg to 30mg per 1m,
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when the manufactured tow band having a length of 250mm is loaded with a load of 250g in a direction to straighten the crimp of the cellulose acetate fiber; l1 is the length of the tow band when loaded with 2500g of load along the direction against the manufactured tow band having a length of 250 mm.
9. The method for producing a cellulose acetate tow band according to any one of claims 5 to 8, further comprising a conveying step of winding the cellulose acetate fiber around a godet roller and conveying the cellulose acetate fiber to a predetermined downstream side in a carrying-out direction,
in the spinning step, the spinning dope is discharged from the plurality of spinning holes of the spinneret in which the plurality of spinning holes are formed,
the winding speed V2 when the cellulose acetate fiber is wound by the godet is set to a value in the range of 400m/min to 900m/min, and the ratio V2/V1 between the winding speed V2 and the discharge speed V1 when the spinning dope is discharged from the plurality of spinning holes of the spinneret is set to a value in the range of 1.0 to 1.8.
Technical Field
The present invention relates to a cellulose acetate tow band and a method for producing a cellulose acetate tow band.
Background
In the present specification, the terms defined as follows are used.
TD: the total fiber (total denier) means the fiber (grams per 9000 m) of a tow aggregate (tow band).
FD: is single fiber (denier per filament) and means the fiber (grams per 9000 m) of a single fiber (1 filament). Also referred to as filament denier.
Monofilament: refers to continuous long fibers (long fibers), and particularly to single fibers that are ejected from the spinning orifices described below.
Spinning holes: refers to the holes of the spinneret described below through which the monofilaments are discharged.
A tow band: the filament bundle, which is an aggregate of monofilaments (single fibers) discharged from a plurality of spinning tubes, is united, and TD is set to a predetermined value. The united tow having TD set to a predetermined value is crimped. The crimped tow (filament aggregate) is a tow band. That is, the tow band has a TD and a crimp number. The tow band is baled into a bundle.
Tow: refers to an assembly of a plurality of monofilaments discharged from a spinning hole. Rovings (end) or yarns (yam) are also one form of tow.
Roving: the present invention refers to a monofilament assembly in which a plurality of monofilaments discharged from a plurality of spinning holes are united (bundled) to have a predetermined total denier.
Yarn: refers to a bundle of monofilaments spun from 1 spinning cylinder. Therefore, the yarn is an aggregate of monofilaments before being united.
Fibers made of cellulose acetate, particularly cellulose diacetate, are useful as materials for cigarette filters used in cigarettes including electronic cigarettes, as materials for absorbers of sanitary goods, and the like. In these applications, cellulose acetate tow bands composed of cellulose acetate fibers may be used.
In general, when cellulose acetate fibers are spun, a spinning dope (also referred to as dope) obtained by dissolving cellulose acetate in an organic solvent is ejected from spinning holes of a spinneret. Then, the solvent in the spinning dope is evaporated to perform spinning (shaping). In a conventional dope, titanium dioxide is contained as an essential component in the form of a matting agent for cellulose acetate fibers or the like. In spinning cellulose acetate fibers, acetone is often used as an organic solvent contained in a spinning dope (non-patent document 1).
As disclosed in patent document 1, when a cellulose acetate tow band (hereinafter, also simply referred to as a tow band) is manufactured, a yarn is formed from a plurality of cellulose acetate fibers. The plurality of yarns are integrated to form a tow. Tow bands are produced by crimping tow. The tow band is packed in a packing box and compressed.
Here,
Disclosure of Invention
Problems to be solved by the invention
Tow bands have excellent properties brought about by cellulose acetate fibers, but it is desirable to increase manufacturing efficiency to reduce production costs. However, when cellulose acetate fibers are spun at high speed, yarn breakage may occur, and it is difficult to improve production efficiency.
Accordingly, an object of the present invention is to improve the production efficiency of a cellulose acetate tow band by preventing yarn breakage during spinning of cellulose acetate fibers.
Means for solving the problems
Through the research of the present inventors, it was found that one of the causes of yarn breakage occurring when cellulose acetate fibers are spun is titanium dioxide contained in a tow band. It has also been found that such yarn breakage can be prevented by spinning cellulose acetate fibers in such a manner that the titanium dioxide content of the tow band produced is reduced as much as possible. In particular, it has also been found that in the case of manufacturing tow bands having a large denier per filament, it is preferable to spin cellulose acetate fibers in such a manner that the titanium dioxide content of the resulting tow band is reduced as much as possible.
Further, as a general technical common knowledge, titanium dioxide is considered to reduce the frictional resistance of cellulose acetate fibers by increasing the unevenness of the fiber surface. However, in the studies of the present inventors, when the content of titanium dioxide in the produced tow band is reduced, the frictional resistance of the cellulose acetate fiber is reduced. Therefore, when the cellulose acetate fiber is guided in a predetermined direction in the manufacturing apparatus, or is curled in particular, the friction force to which the cellulose acetate fiber is externally subjected is reduced.
When the frictional force received by the cellulose acetate fibers from the guide (guide) member is too large, the cellulose acetate fibers become a factor of fly (fluff or filament of short fibers). On the other hand, when the frictional force of the cellulose acetate fiber received by the guide member is too small, the guide position of the cellulose acetate fiber (yarn or roving) in the guide member becomes unstable. In particular, the relative positional relationship between the roving and the nip roller when the roving enters the crimping device may vary, and the crimping may not be performed constantly. The crimped state of the tow band thus crimped is not constant. Therefore, when the tow band is used for manufacturing a cigarette filter, the ventilation resistance of the cigarette filter varies in the longitudinal direction of the tow band, which causes a problem.
Therefore, it is important to properly guide and crimp the cellulose acetate fibers, and for this reason, it is necessary to set the frictional resistance of the cellulose acetate fibers within a certain range. The above problems are clearly observed, particularly in the case of tow bands having a high crimp ratio. The above problems are particularly found in tow bands having a small total denier. Therefore, it is difficult to manufacture a tow band having a small total denier, a high crimp rate, and a small titanium dioxide content. In addition, even if crimping is possible, the quality of the tow band may be reduced. The present invention is based on such an insight.
An acetate tow band according to one embodiment of the present invention is a tow band made of acetate fibers, the total denier of which is set to a value in the range of 8000 or more and 44000 or less, the titania content of which is set to a value in the range of 0% by weight or more and 0.01% by weight or less, and the content of a fiber finish agent measured by an ether extraction method of the tow band is set to a value in the range of more than 5mg and 65mg or less per 1 m.
According to the above configuration, in the case of manufacturing a cellulose acetate tow band in which the total denier is set to a value in the range of 8000 or more and 44000 or less, the content of titanium dioxide in the cellulose acetate tow band can be reduced as much as possible to the extent that the cellulose acetate tow band does not substantially contain titanium dioxide. Therefore, when cellulose acetate fibers are spun at high speed, yarn breakage just below the spinneret can be prevented favorably.
In addition, according to the above configuration, the content of the fiber finish in the tow band measured by the ether extraction method is set to a value in a range of more than 5mg and 65mg or less per 1 m. Therefore, when the cellulose acetate fiber having the titanium dioxide content set as described above is guided or curled in a predetermined direction, for example, a reduction in the frictional force to which the cellulose acetate fiber is externally subjected can be prevented. In particular, defective curling due to a decrease in frictional resistance when cellulose acetate fibers are curled can be suppressed. Therefore, a high-quality cellulose acetate tow band can be stably produced.
The filament denier may be set to a value in the range of 1.0 or more and 12.0 or less. This prevents yarn breakage during spinning of the cellulose acetate fiber. In addition, the degree of freedom in setting the denier per filament in the cellulose acetate tow band can be improved.
The following may be the case: the denier per filament is set to a value in the range of 1.0 or more and less than 5.0, the cellulose acetate fiber is crimped, and the crimp percentage (%) of the tow band calculated by the formula 1 is set to a value in the range of 10% or more and 40% or less.
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when a load of 250g is applied to the tow band having a length of 250mm in the direction in which the curl of the cellulose acetate fiber is straightened. L1 is a length of the tow band when 2500g of load is applied to the tow band having a length of 250mm in the above direction.
According to the above configuration, yarn breakage can be prevented when spinning fine cellulose acetate fibers having a denier per filament set to a value in the range of 1.0 or more and less than 5.0. Further, by setting the crimping rate (%) of the cellulose acetate tow band to a value in the range of 10% to 40%, it is possible to stably produce a suitably crimped cellulose acetate tow band.
The following may be the case: the denier per filament is set to a value in the range of 5.0 to 9.0, the total denier is set to a value in the range of 15000 to 20000, the content of the fiber finish of the tow band measured by the ether extraction method is set to a value in the range of 10mg to 30mg per 1m, the cellulose acetate fiber is crimped, and the crimp ratio (%) of the tow band calculated by the formula 1 is set to a value in the range of 10% to 30%.
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when a load of 250g is applied to the tow band having a length of 250mm in the direction in which the curl of the cellulose acetate fiber is straightened. L1 is a length of the tow band when 2500g of load is applied to the tow band having a length of 250mm in the above direction.
According to the above configuration, the filament denier is set to a value in the range of 5.0 or more and 9.0 or less, and the total denier is set to a value in the range of 15000 or more and 20000 or less, whereby even if the filament denier is set to be large and the total denier is set to be small, a tow band which is well crimped so that the crimp percentage (%) is set to the value in the above range can be obtained.
A method for producing a cellulose acetate tow band according to an embodiment of the present invention includes the steps of: a spinning dope preparation step in which a spinning dope is prepared; a spinning step in which a plurality of cellulose acetate fibers are spun using the spinning dope so that the total denier of the manufactured tow band is set to a value in the range of 8000 or more and 44000 or less; and an addition step of adding a fiber finish to the cellulose acetate fiber so that the content of the fiber finish of the produced tow band measured by an ether extraction method is set to a value in a range of more than 5mg and not more than 65mg per 1m, wherein the spinning dope preparation step prepares the adjusted spinning dope so that the content of titanium dioxide of the produced tow band is set to a value in a range of 0 wt% or more and not more than 0.01 wt%.
According to the above method, it is possible to reduce the content of titanium dioxide in the cellulose acetate tow band as much as possible in the case of manufacturing the cellulose acetate tow band in which the total denier is set to a value in the range of 8000 or more and 44000 or less, to the extent that the cellulose acetate tow band does not substantially contain titanium dioxide. Therefore, when cellulose acetate fibers are spun at high speed in the spinning step, yarn breakage just below the spinneret can be prevented favorably.
Further, according to the above method, the fiber finish is added to the cellulose acetate fiber in the adding step so that the content of the fiber finish measured by the ether extraction method of the manufactured tow band is set to a value in a range of more than 55mg and 65mg or less per 1 m.
Therefore, the content of the finish oil in the cellulose acetate tow band can be set to be small within a range necessary for producing the cellulose acetate tow band. Thus, when the cellulose acetate fiber having the titanium dioxide content set as described above is guided in a predetermined direction or curled, for example, the friction force to which the cellulose acetate fiber is externally subjected can be prevented from being reduced. In particular, defective curling due to a decrease in frictional resistance when cellulose acetate fibers are curled can be suppressed. Therefore, a high-quality cellulose acetate tow band can be stably produced.
In the spinning step, the cellulose acetate fiber having a denier per filament set to a value in the range of 1.0 to 12.0 may be spun. According to this method, the filament denier is set to a value in the range of 1.0 or more and 12.0 or less. In addition, a cellulose acetate tow band substantially free of titanium dioxide can be stably produced.
The method may further comprise a crimping step of crimping the cellulose acetate fiber so that a crimp percentage (%) of the manufactured tow band calculated by the formula 1 is set to a value in a range of 10% to 40%, and the spinning step may spin the cellulose acetate fiber having a denier per filament set to a value in a range of 1.0 to less than 5.0.
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when a load of 250g is applied to the tow band after production having a length of 250mm in the direction in which the crimp of the cellulose acetate fiber is straightened. L1 represents the length of the tow band when 2500g of load is applied to the tow band after manufacture, which has a length of 250mm, in the above direction.
According to the above method, it is possible to prevent yarn breakage when spinning fine cellulose acetate fibers having a denier per filament set to a value in the range of 1.0 or more and less than 5.0 in a spinning device. The cellulose acetate fibers were crimped with a crimping device so that the crimping rate (%) was set to a value in the range of 10% to 40%. This enables stable production of a suitably crimped cellulose acetate tow band.
The method may further include a crimping step of crimping the cellulose acetate fiber so that a crimp percentage (%) of the manufactured tow band calculated by the formula 1 is set to a value in a range of 10% to 30%, and the spinning step may be performed so that the plurality of cellulose acetate fibers are spun so that a denier per filament of the manufactured tow band is set to a value in a range of 5.0 to 9.0 and less and a total denier is set to a value in a range of 15000 to 20000, and the applying step may be performed so that a fiber finish is applied to the cellulose acetate fiber so that a content of the fiber finish measured by an ether extraction method of the tow band is set to a value in a range of 10mg to 30mg per 1 m.
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Wherein L0 is the length of the tow band when a load of 250g is applied to the tow band after production having a length of 250mm in the direction in which the crimp of the cellulose acetate fiber is straightened. L1 represents the length of the tow band when 2500g of load is applied to the tow band after manufacture, which has a length of 250mm, in the above direction.
According to the above method, the filament denier is set to a value in the range of 5.0 or more and 9.0 or less, and the total denier is set to a value in the range of 15000 or more and 20000 or less, whereby even a tow band having a large filament denier and a small total denier can be well crimped so that the crimp ratio (%) is set to the value in the above range.
The method may further include a conveying step of winding the cellulose acetate fiber around a godet and conveying the cellulose acetate fiber to a downstream side in a predetermined carrying-out direction, wherein in the spinning step, the spinning dope is discharged from the plurality of spinning holes of a spinneret in which the plurality of spinning holes are formed, a winding speed V2 at the time of winding the cellulose acetate fiber around the godet is set to a value in a range of 400m/min to 900m/min, and a ratio V2/V1 of the winding speed V2 to a discharge speed V1 at the time of discharging the spinning dope from the plurality of spinning holes of the spinneret is set to a value in a range of 1.0 to 1.8.
According to the above method, yarn breakage can be prevented when the cellulose acetate fiber is spun in the spinning step. The ratio V2/V1 is set to a value in the range of 1.0 to 1.8. This allows cellulose acetate fibers to be spun more efficiently while imparting tension.
In addition, a wide setting range of the ratio V2/V1 can be ensured. Therefore, for example, a plurality of types of cellulose acetate fibers having different deniers per filament can be efficiently spun by adjusting the ratio V2/V1 while using the same spinneret.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, the production efficiency of a cellulose acetate tow band can be improved by preventing yarn breakage during spinning of cellulose acetate fibers.
Drawings
Fig. 1 is an overall view of a tow band manufacturing apparatus according to an embodiment.
Fig. 2 is a graph showing the relationship between the winding speed of the yarn and the maximum draft (draft) in examples and comparative examples.
Detailed Description
(embodiment mode)
Embodiments of the present invention will be described with reference to the drawings. In the following description, the conveying direction refers to a conveying direction of a monofilament (fiber) 30 of cellulose acetate (hereinafter, also referred to as CA), a yarn 31, a roving 32, and a CA tow band 33 (hereinafter, also referred to as a tow band 33).
Fig. 1 is an overall view of a cellulose acetate tow band manufacturing apparatus 1 (hereinafter, also referred to as a manufacturing apparatus 1). In the manufacturing apparatus 1, the
The manufacturing apparatus 1 uses a spinning dope 22 obtained by dissolving a cellulose acetate sheet such as cellulose diacetate in an organic solvent. The spinning dope 22 is mixed in the
The
The yarn 31 to which the fiber finish has been added can be further narrowed in width by the guide pins 7 and 8. Then, the yarn 31 is wound by the godet 6. The yarn 31 is drawn by a predetermined winding device after traveling around the peripheral surface of the godet 6 for only about 3/4 cycles. A series of units for producing the yarn 31, that is, a spinning unit 4 for ejecting a dope 22 from a spinneret 15 and spinning a
The yarn 31 is pulled in a horizontal direction from the peripheral surface of the godet roller 6 by a winding device. For the yarn 31 passing from each station, the direction of guiding can be turned by 90 ° by means of the guide pins 7, 8. Each yarn 31 is carried along the arrangement direction of the stations, and is sequentially gathered or stacked. Thereby, the plurality of yarns 31 are gathered into a bundle to form a roving (tow) 32 as a flat aggregate of the yarns 31. The
The crimping device 9 includes a pair of nip rollers 16 and 17 for pressing the roving 32 into a stuffer box (crimping box) 18. As the roving 32 is pressed into the stuffer box 18 by the pair of nip rollers 16, 17, resistance is generated from within the stuffer box 18. However, the
Here, the method for manufacturing the tow band 33 according to the present embodiment includes a spinning dope preparation step, a spinning dope filtration step, a spinning dope conveyance step, a spinning step, an attachment step, a guide step, and a crimping step.
In the spinning dope preparation step, a spinning dope 22 is prepared. Specifically, as the dope 22, a dope adjusted so that the titania content (hereinafter, also simply referred to as titania content) of the manufactured tow band 33 is set to a value in the range of 0 wt% or more and 0.01 wt% or less is prepared. That is, the tow band 33 of the present embodiment may not contain titanium dioxide. Therefore, the case where the titanium dioxide is 0% by weight or more includes: the case of no titanium dioxide; and the case where titanium dioxide is contained only in a trace amount below the analysis limit value.
However, as described above, the method for producing the tow band 33 includes the dope producing step, the dope filtering step, and the dope conveying step. In the production of a normal tow band, a tow band containing titanium dioxide is produced. Therefore, the method for producing the tow band 33 according to the present embodiment also includes a case where titanium dioxide is unintentionally contained in the dope producing step, the dope filtering step, or the dope carrying step.
The titanium dioxide content in the manufactured tow band 33 can be measured by atomic absorption spectrometry or the like. The titania content in the manufactured tow band 33 may be determined according to the chemical fiber monofilament test method defined in JIS L1013: 2010 the measurement is carried out. As the instrument used in the test method defined in JIS L1013, an instrument defined in JIS K0050 can be used. The test method is specifically described below.
a) The oven-dried mass of about 5g of the sample of the manufactured tow band 33 was determined, and the sample was ashed in an electric furnace so as to avoid burning. This was transferred to a 200mL beaker with a small amount of water, and the beaker was heated to remove water. Then, 15mL of special concentrated sulfuric acid (specific gravity 1.84) specified in JIS K8951 and about 10g of special ammonium sulfate specified in JIS K8960 were added, and the mixture was covered with a petri dish. Then, the liquid was heated first slowly on a sand bath and at the end strongly until the liquid became transparent.
b) After leaving to cool, water was added to the reaction solution so that the total amount of the solution became about 100mL, with care taken not to make the solution temperature 50 ℃ or higher. It was transferred to a 1L volumetric flask and diluted with water to the mark. From this liquid, a mL (an amount such that the absorbance of the color developing solution becomes 0.3 to 0.5 depending on the content of titanium dioxide and the thickness of a cell) of the liquid was transferred to a 50mL volumetric flask with a pipette. Then, 5mL of a special grade aqueous hydrogen peroxide solution (3%) defined in JIS K8230 and 10mL of special grade 1mol/L sulfuric acid defined in JIS K8951 were added to the liquid in the flask to develop the color of the liquid. The liquid was then diluted with water to the scale line.
c) The liquid in the flask was transferred to a cuvette and the absorbance at a wavelength of 420nm was measured with a photoelectric colorimeter. From the measured value, the titania concentration (g/50mL) was determined using a calibration curve prepared in advance. Then, the percentage of titanium dioxide was calculated by the following
[ formula 2]
T1(％)＝((B×1000)/(C×A))×100
Wherein T1 is titanium dioxide (%), A is the collected diluted solution (mL), B is the titanium dioxide concentration (g/50mL), and C is the oven-dried mass (g) of the sample. The titanium dioxide content in the manufactured tow band 33 can be measured by a gravimetric method in addition to the atomic absorption spectrometry and JIS method described above.
In the filtration step, the spinning dope 22 is filtered. In the spinning step, the spinning dope 22 prepared in the above manner is used to spin a plurality of
In the conveyance step, the
The winding speed V2 is preferably a value in the range of 500m/min to 900m/min, and more preferably a value in the range of 550m/min to 900 m/min. The lower limit of the ratio V2/V1 is preferably 1.1 or more, and more preferably 1.2 or more. The upper limit of the ratio V2/V1 is preferably 1.7 or less, and more preferably 1.4 or less.
In the attaching process, a fiber finish is attached to the
Specifically, in the attaching step, the fiber finish is attached to the
The oven-dried mass of about 5g of the sample of the manufactured tow band 33 was obtained, and the sample was gently placed in a soxhlet extractor specified in JIS R3503 without using a cylindrical filter paper. Then, 100mL to 150mL of special grade diethyl ether defined in JIS K8103 was added to the accompanying flask. The subsidiary flask was placed on a water bath, and heated for 1.5 hours to such an extent that the extract kept slightly boiling (to such an extent that the solvent was refluxed by passing through a siphon tube at a frequency of 1 time for 10 minutes). Then, the solution accumulated in the sample portion was returned to the attached flask. The contents of the accompanying flask were concentrated to 10mL to 15mL, and then filtered using a glass filter of 1G1 or 3G1 as needed. This was transferred to a weighing flask in which a constant weight was determined in advance at 105. + -. 2 ℃.
The extraction flask (attached flask) was washed with diethyl ether, and the washing solution was collectively added (after filtration with the above glass filter in the case of using a glass filter) to a weighing bottle, and the solvent was evaporated on a water bath. Then, the mixture was placed in a thermostatic dryer at 105. + -. 2 ℃ for 1.5 hours, cooled in the dryer, and the mass of the extracted component was weighed.
The extracted components were expressed as a percentage of the ether extraction amount with respect to the mass of an oven-dried sample, and the average of 2 times was rounded to the 2 nd decimal place according to rule B (rounding method) defined in JIS Z8401.
In the attaching step of the present embodiment, the fiber finish emulsion is attached to the
When the content of the fiber finish measured by the ether extraction method in the produced tow band exceeds 65mg per 1m, the production cost of the tow band may be increased. In addition, it may be difficult to guide the yarn and the tow by means of the guide pins 7, 8. In addition, the tow may not be properly crimped in the crimping device 9. In addition, when a cigarette filter is manufactured using the tow band, the weight of the tow band per unit weight of the cigarette filter may be reduced, and the necessary ventilation resistance may not be obtained.
Further, if the tow band is not added with the fiber finish or the content of the fiber finish measured by the ether extraction method of the tow band after production is less than 5mg per 1m, friction of the yarn and the tow received from contact with the guide pins 7, 8 and the like increases. This may cause damage and fly.
Further, if the content of the fiber finish measured by the ether extraction method of the manufactured tow band is less than 5mg per 1m, the amount of the fiber finish attached to the yarn 31 may decrease during the conveyance of the yarn 31, and it may be difficult to maintain an oil film. As a result, the traveling position of the yarn 31 may become unstable. In addition, the crimp of the roving 32 in the crimping step described later may become unstable. As a result, the amount of fly may increase. In the manufacturing apparatus 1, the frictional resistance to which the yarn 31 and the roving 32 are externally applied may be excessive.
In the guiding step, the
In the crimping process, the roving 32 is crimped. For example, in the spinning step, the
[ formula 1]
The percentage of crimp (%) [ (L1-L0)/L0] × 100
Here, L0 is the length of the tow band 33 when a load of 250g is applied to the manufactured tow band 33 having a length of 250mm in the direction in which the crimp of the
As described above, when the CA monofilament is spun by the dry spinning method, acetone is used as a solvent for the spinning dope. Here, a significant problem in spinning a CA monofilament by a dry spinning method using a spinning dope obtained by dissolving cellulose acetate in acetone is yarn breakage. The yarn breakage means that the CA monofilament in dry spinning is broken in the middle of the dry spinning process. There are multiple locations where yarn breakage occurs. The main yarn breakage portions are portions where friction is generated with the CA monofilament, such as a godet and a leader pin.
In recent years, as the use of CA monofilaments has expanded from the use for cigarettes to the use for materials for absorbent bodies of sanitary products, etc., attempts have been made to increase the spinning speed and increase the production amount of tow bands. Accordingly, the number of broken filaments immediately below the spinning hole of the spinneret 15 increases. In this embodiment, yarn breakage just below the spinning holes of the spinneret 15 can be prevented.
Increasing the manufacturing speed of the tow band means increasing the spinning speed. Increasing the spinning speed while obtaining tow bands of the same single fiber diameter (in other words, the same FD) means increasing the speed at which the dope passes through the spinning hole (the speed at which the dope is ejected from the spinning hole [ the amount of ejection per unit time ]).
Here, the present inventors found out that one of the causes of such yarn breakage is titanium dioxide contained in the produced tow band. When the spinning dope contains titanium dioxide, yarn breakage occurs when the discharge speed at the time of spinning the CA monofilament is increased to a certain level or more.
The cause of the yarn breakage is unclear. However, it is considered that the flow of the dope discharged from the spinning hole becomes unstable due to the change in physical properties such as viscosity and fluidity of the dope by titanium dioxide. In addition, primary particles of titanium dioxide contained in a solid form in the spinning dope may be aggregated to become secondary particles. It is considered that the secondary particles block at least a part of the spinning holes of the spinneret to inhibit the flow of the spinning solution in the vicinity of the spinning holes. Therefore, when the discharge speed of the dope is increased, the fluidity of the dope in the spinning hole may become unstable due to the problem of the liquid viscosity of the dope, and the yarn breakage frequency may increase.
Therefore, in the present embodiment, it is specified that the titania in the dope 22 is reduced as much as possible. Specifically, in the dope preparation step of the present embodiment, the amount of titanium dioxide added to the dope 22 is adjusted so as to be substantially 0. Thus, the titania content of the produced tow band 33 is in the range of 0 wt% to 0.01 wt%. In the spinning step of the present embodiment, the plurality of
In the addition step, the fiber finish is added to the
Thus, the tow band 33 is composed of the
The content of the fiber finish measured by the ether extraction method after production of the tow band 33 is set to a value in a range of more than 5mg and 65mg or less per 1 m.
Thus, when the tow band 33 is produced, the content of titanium dioxide in the spinning solution can be reduced as much as possible, and the spinning solution can be set to a level substantially free of titanium dioxide. Therefore, when the
The CA monofilament containing substantially no titanium dioxide has a difference in physical properties from the CA monofilament containing substantially titanium dioxide, and thus the friction force received from the guide member such as the guide pin is reduced. This makes it difficult for the CA monofilament to be stably guided by the guide member.
In this case, when the yarn is not guided well, the yarn distribution in the roving in which a plurality of yarns carried out from the spinning cylinders are aligned becomes uneven. Therefore, it is difficult to uniformly crimp the roving using the crimping device. In addition, it is difficult to increase the number of crimps of the tow band. In addition, the frictional resistance between the roving and the pair of nip rollers of the crimping device is reduced. Therefore, each grip roller rubs the roving, whereby the generation amount of fly may increase.
On the other hand, the frictional resistance of the
In addition, in the case of manufacturing a cigarette filter using the tow band 33, the tow band 33 is drawn out from the packing box. Then, the tow band 33 is opened, and may be formed into a cylindrical shape with the addition of a plasticizer. The higher viscosity fiber finish is added to the tow band 33 by the
The TD of the tow band 33 is preferably a value in the range of 10000 to 37000, more preferably 12000 to 25000, and particularly preferably 12000 to 22000. The FD of the tow band 33 is preferably a value in the range of 3.0 to 10.0, more preferably a value in the range of 3.3 to 9.0, and particularly preferably a value in the range of 5.0 to 9.0.
The content of the fiber finish in the manufactured tow band 33 measured by the ether extraction method is preferably a value in a range of more than 5mg and 45mg or less per 1m, more preferably a value in a range of more than 5mg and 38mg or less, and particularly preferably a value in a range of more than 5mg and 35mg or less.
In addition, with the tow band 33, FD is set to a value in a range of 1.0 or more and 12.0 or less, and TD is set to a value in a range of 15000 or more and 44000 or less. Therefore, yarn breakage can be prevented when the
In the tow band 33 of the present embodiment, FD is set to a value in the range of 1.0 or more and less than 5.0, and the crimping rate (%) is set to a value in the range of 10% or more and 40% or less, as an example. Therefore, yarn breakage can be prevented when the
Here, in the tow band 33, it is preferable that FD is set to a value in a range of 5.0 to 9.0 inclusive, TD is set to a value in a range of 15000 to 20000 inclusive, the content of titanium dioxide is set to a value in a range of 0 wt% to 0.01 wt% inclusive, and the content of the fiber finish measured by the ether extraction method is set to a value in a range of 10mg to 30mg per 1 m. In this case, the crimping rate (%) of the tow band 33 is preferably set to a value in the range of 10% to 30%.
In the case of tow bands having a large FD, curling is difficult, particularly high-curling is difficult, without titanium dioxide. However, in the tow band 33 of the present embodiment, FD is set to a value in the range of 5.0 to 9.0 inclusive, and TD is set to a value in the range of 15000 to 20000 inclusive, whereby even if FD is set to be large and TD is set to be small, the fiber finish is contained in the above content, and therefore, the tow band can be curled well so that the crimp ratio (%) is set to a value in the range of 10% to 30%.
Specifically, the crimping of the
Further, according to the above-described method for manufacturing the tow band 33, yarn breakage can be prevented when the
In addition, a wide setting range of the ratio V2/V1 can be ensured. Therefore, for example, by adjusting the ratio V2/V1 while using the same spinneret 15, it is possible to efficiently spin a plurality of kinds of
In addition, the tow band 33 contains substantially no titanium dioxide. Therefore, for example, when the tow band 33 is used as a material of an absorbent body of a sanitary product, the sanitary product can be favorably used even by a user or the like who has an allergic reaction to titanium dioxide.
It is needless to say that the ratio V2/V1 may be set to a value in a range other than the above range (for example, a value in a range of more than 1.8 and not more than 10.0). The winding speed V2 can be set to a value in the range of 100m/min or more and less than 400m/min, for example. Even if the ratio V2/V1 and the winding speed V2 are set to values within such a numerical range, the
(confirmation test)
[ test 1]
A plurality of tow bands No.1 to 6 having different FD and TD were produced, and the preferable range of the fiber finish oil content in each tow band was measured. Specifically, a spinning dope 22 was prepared by dissolving CA (acetyl degree of substitution 2.5) in acetone with a target composition of 29.0 wt% of CA, 68.5 wt% of acetone, and 2.5 wt% of water for the spinning dope 22.
A spinneret 15 having a plurality of spinning holes (having a triangular opening shape with one side having a predetermined length) formed therein is prepared. The spinning dope 22 was heated to 50 ℃, filtered by the
The fiber finish emulsion of the
The contact pressure of the yarn 31 and the finish
The
No. 1: a tow band (3Y 35000 in table 1) in which FD was set to 3.0 and TD was set to 35000 and the radial cross-sectional shape was Y-shaped.
No. 2: a tow band (3Y 28000 in table 1) in which FD is 3.0 and TD is 28000 and the radial cross-sectional shape is Y-shaped.
No. 3: a tow band in which FD is set to 4.0 and TD is set to 25000 and the radial cross-sectional shape is Y-shaped (described as 4Y25000 in table 1).
No. 4: a tow band in which FD is set to 5.0 and TD is set to 20000, and the radial cross-sectional shape is a Y shape (described as 5Y20000 in table 1).
No. 5: a tow band in which FD is set to 6.0 and TD is set to 17000 and the radial cross-sectional shape is Y-shaped (described as 6Y17000 in table 1).
No. 6: a tow band in which FD is set to 8.0 and TD is set to 15000, and the radial cross-sectional shape is Y-shaped (described as 8Y15000 in table 1).
The yarn 31 guiding stability and roving stability in the crimping apparatus were evaluated in the production of the tow bands 33 of nos. 1 to 6. The evaluation of the guiding stability of the yarn 31 is performed by confirming whether or not the yarn 31 is guided properly by the guide pins 7, 8.
Specifically, a case where the position of the yarn 31 during travel is constant and does not vary with respect to the positions of the guide pins 7 and 8 is evaluated as a 1. A condition in which the yarn 31 is spinnable despite the position of the running yarn being varied with respect to the positions of the guide pins 7 and 8 is evaluated as a 2. In addition, a case where the yarn 31 was wound around the guide pins 7 and 8 during the long-time manufacturing process of the tow band 33 was evaluated as a 3. The evaluation was decreased in the order of A1, A2 and A3.
Further, a case where the position of the running roving 32 is constant and does not vary with respect to the position of the nip rollers 16 and 17 at the position immediately before the nip rollers 16 and 17 of the crimping device 9 was evaluated as B1. Further, a case where the position of the running roving 32 may fluctuate with respect to the position of the nip rollers 16 and 17 at a position immediately before the nip rollers 16 and 17 was evaluated as B2.
A case where the position of the running roving 32 is unstable with respect to the position of the nip rollers 16 and 17 at a position immediately before the nip rollers 16 and 17 was evaluated as B3. Further, a case where the position of the running roving 32 constantly fluctuates with respect to the position of the nip rollers 16 and 17 at the position immediately before the nip rollers 16 and 17 was evaluated as B4. The evaluations were decreased in the order of B1, B2, B3 and B4.
In this test, the range of the fiber finish content per 1m of the tow band 33 in which relatively good evaluation results were obtained is shown in table 1. Table 1 shows the content (mg) of the fiber finish per 1m of the produced tow band 33 measured by the ether extraction method.
In this test, the results of evaluation of the guiding stability of the yarn 31 and the stability of the roving 32 at the entrance of the crimping device 9 (the position immediately before the pair of nip rollers 16 and 17) are shown in table 2.
Table 2 shows the oil agent application conditions X1 to X10. In the finish oil application conditions X1 to X10, the contact pressure of the yarn 31 with the finish
[ Table 1]
＊ measurement based on Ether extraction
[ Table 2]
As shown in table 1, it is understood that all the tow bands 33 of nos. 1 to 6 have good results when the content of the fiber finish agent per 1m of the tow band is in the range of 11.0mg or more and 64.1mg or less.
As shown in table 2, it is found that, in the case of nos. 4 to 6, that is, FD is set to a value in the range of 5.0 to 8.0 inclusive, and TD is set to a value in the range of 15000 to 20000 inclusive, good results are obtained particularly when the content of the finish oil per 1m of the tow band 33 is in the range of 11.0 to 27mg inclusive.
Further, as a result of other studies by the present inventors, it was found that in all of the tow bands of nos. 1 to 6, when the content of the fiber finish per 1m of the tow band is in the range of 15.0mg or more and less than 42.8mg, more favorable results were obtained.
Further, it is found that the tow bands of Nos. 1 to 6 showed good results when the content of the fiber finish per 1m of each tow band was more than 5.0mg, particularly 11.0mg or more.
Therefore, it is understood that, even when the tow band does not contain titanium dioxide, good results are obtained to some extent even when the tow band has a value in a range smaller than the lower limit value (mg) shown in table 1.
As is clear from tables 1 and 2, it is important to obtain production stability of a tow band containing no titanium dioxide and having a large FD and a small TD, if the content of the fiber finish is less than that of a normal tow band (tow band of 3Y35000 of No. 1). Subsequently, examples 1 to 4 and comparative examples 1 to 2 were produced in the following manner, and a plurality of confirmation tests were performed. The number of crimps (in/inch) of examples 1 to 4 and comparative examples 1 to 2 was measured in the following manner: in the measurement method described in japanese patent application laid-open No. 7-316975, the surface of the illuminated tow band is photographed by a photographing means, and the photographed image is subjected to computer processing.
[ example 1]
A spinning dope 22 was prepared by dissolving CA (degree of substitution of acetyl group 2.5) in acetone with a target composition of 29.0 wt% of CA, 68.5 wt% of acetone, and 2.5 wt% of water for the spinning dope 22. That is, the tow band 33 of example 1 does not contain titanium dioxide.
A spinneret 15 having 600 spinning holes formed therein, which has a triangular opening shape with one side of 60 μm, was prepared. The spinning dope 22 was heated to 50 ℃, filtered by the
The fiber finish emulsion of the
Using the
[ example 2]
A tow band 33 of example 2 was obtained in the same manner as in example 1 except that the content of the fiber finish measured by the ether extraction method in the manufactured tow band 33 was adjusted to 41.0mg per 1m, and 67.5 parts of mineral oil having a saybolt universal viscosity of 100 seconds at 210 ℃ was used as the mineral oil contained in the fiber finish emulsion, and FD was set to 3.0 and TD was set to 35000. That is, the tow band 33 of example 2 does not contain titanium dioxide. The number of crimps of the tow band 33 of example 2 was set to 34.0 per 1 inch.
[ example 3]
A tow band 33 of example 3 was obtained in the same manner as in example 1 except that the tow band 33 after production was spun using a spinneret 15 having 350 spinning holes (having an opening shape with a triangle having 58 μm side), and the content of the fiber finish measured by the ether extraction method was adjusted to 41.0mg per 1m, and the value of FD was set to a range of more than 2.7 and less than 3.0, and the TD was set to 35000. That is, the tow band 33 of example 3 does not contain titanium dioxide. The number of crimps of the tow band 33 of example 3 was set to 34.0 per 1 inch.
[ example 4]
A tow band 33 of example 4 was obtained in the same manner as in example 1 except that spinning was performed using a spinneret 15 having 600 spinning holes (having an opening shape with one side being a triangle of 56 μm) and the number of crimps was changed by setting the crimping device 9, and that the FD was set to 2.7 and the TD was set to 35000. That is, the tow band 33 of example 4 does not contain titanium dioxide. The number of crimps of the tow band 33 of example 4 was set to 33.5 per 1 inch.
Comparative example 1
A tow band of comparative example 1 was obtained in the same manner as in example 1 except that a dope was prepared so that the target composition of the dope was CA 28.9 wt%, titanium dioxide 0.1 wt%, acetone 68.5 wt%, and water 2.5 wt%. The number of crimps of the tow band 33 of comparative example 1 was set to 34.0 per 1 inch.
Comparative example 2
A tow band of comparative example 2 was obtained in the same manner as in example 3 except that a dope was prepared so that the target composition of the dope was CA 28.9 wt%, titanium dioxide 0.1 wt%, acetone 68.5 wt%, and water 2.5 wt%. The number of crimps of the tow band 33 of comparative example 2 was set to 34.0 per 1 inch. The setting conditions of examples 1 to 4 and comparative examples 1 to 2 are shown in Table 3.
[ Table 3]
[ test 2]
The dynamic friction coefficient between each yarn and the guide pin 7 when each yarn of example 1 and comparative example 1 was guided by the guide pin 7 of the manufacturing apparatus 1 was measured. Specifically, a plurality of guide pins 7 (10 mm in diameter) having a constant surface roughness in the contact area with the yarn were prepared. The contact angle theta of the yarn with the guide pin 7 is set to 135 deg.. The contact angle θ is defined as an angle between the yarn on the side of the guide pin 7 in the conveying direction and the yarn on the side of the guide pin 7 in the discharging direction, when viewed in the axial direction of the guide pin 7.
Using these guide pins 7, the yarn is wound at a predetermined winding speed using a winding device on the downstream side in the carrying-out direction of the guide pins 7 in the manufacturing apparatus 1. The difference (T2 to T1) between the yarn tension T1 between the godet 6 and the leader 7 at the time of winding and the yarn tension T2 between the leader 7 and the winding device was calculated as the frictional tension. For the calculation method, for example, see japanese patent application laid-open No. 2004-.
The winding speed of the yarn in the winding device is set to any one of 200, 400, 600, 800 and 1000 m/min. The dynamic friction coefficient was calculated by using the friction tension value and the contact angle θ [ rad ] calculated above and using the following
[ formula 3]
Coefficient of kinetic friction (μ d) ═ 1/θ Log (T2/T1)
The measurement results are shown in table 4.
[ Table 4]
As is clear from table 4, the coefficient of dynamic friction of the yarn 31 of example 1 changes depending on the winding speed. The coefficient of dynamic friction of the yarn 31 of example 1 was maximized at a winding speed of 600m/min, and the dynamic friction resistance was reduced in both cases where the winding speed was set to the low speed side and the high speed side. In contrast, the yarn of comparative example 1 exhibited a substantially constant high dynamic frictional resistance with respect to the winding speed. From the results shown in table 3, it was confirmed that the case where the yarn does not contain titanium dioxide is smaller than the case where the yarn contains titanium dioxide in terms of the coefficient of dynamic friction between the yarn and the leader pin.
[ test 3]
Low-speed frictional force (g) acting on the yarn from the guide pins 7, 8 when the yarn is guided by the guide pins 7, 8 in examples 1, 2 and comparative example 1 was measured. Specifically, the following states are obtained: the yarn was wound at 450 ° (5/4 cycles) around a metal pin (referred to as a guide pin 7, 8) having a diameter of 1.5mm, which was arranged to extend in the horizontal direction.
In this state, the yarn hangs down with a predetermined load S1 (30 g in this case) applied to one end portion thereof, and the other end portion of the yarn is inserted into the pulley-equipped spring gauge disposed above the metal pin.
Then, the other end of the yarn was guided downward by turning it 180 ° toward the one end by a pulley of a spring gauge with a pulley, and was wound at a winding speed of 3cm/min by a winding roller. The tension S2 acting on the yarn during winding is measured. Using the measured value, the low-speed frictional force (g) is calculated by the following
[ formula 3]
Low speed friction (g) ═ S2-S1)/2
S1 is a measurement value measured by a pulley-equipped spring gauge. S2 is a load (30 g in the above case) applied to the one end of the yarn. The calculation results are shown in table 5.
[ Table 5]
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