JP2006118091A - Split type conjugate fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a split type conjugate fiber precisely ground without injuring a material to be ground in grinding a precision machine such as a hard disk and the like. <P>SOLUTION: The split type conjugate fiber comprises a polyester component and a polyamide component substantially containing no titanium oxide and the content of cyclic trimers in the polyester component is <1.0%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a split type composite fiber and a method for producing the same. More particularly, the present invention relates to a split type composite fiber suitable for accurately performing a cleaning tool such as a wiping cloth, particularly a precision machine such as a hard disk, without damaging a target part when it is polished or cleaned. .

  Conventionally, in the use of polishing electronic parts, a nonwoven fabric such as polyester is used as a base fabric, and artificial leather impregnated on the surface with a urethane resin or the like as a silver surface, or a composite fiber such as polyester and / or polyamide is formed after the fabric is formed. A polishing cloth or the like that is divided into microfibers is used.

  For example, the capacity of hard disks has been increasing in recent years, and products of 100 GB or more can be seen. These have changed from traditional aluminum hard disks to glass. At the same time, miniaturization of hard disks has progressed remarkably, and in order to satisfy both the increase in capacity and the miniaturization at the same time, it is necessary to precisely polish the disk surface.

  However, in order to cope with artificial leather, the base fabric is made into microfibers and the silver surface is improved.

  On the other hand, microfiber obtained by splitting a composite fiber such as polyester and polyamide as a filament after forming a fabric is inexpensive and has performance suitable for polishing. For example, Patent Document 1 proposes a wiping cloth suitable for polishing a hard disk with a specific driving number and a cover factor by increasing the density of a composite fiber of polyester and polyamide after splitting.

  On the other hand, Patent Document 2 describes that a polyester resin not containing titanium dioxide suitable for bottles and having a low cyclic trimer content is used.

JP 2000-303300 A Japanese Patent Publication No. 7-37515

However, in the fabric of Patent Document 1, oligomers such as cyclic trimers contained in polyester are extracted by a solvent such as acetone or isopropyl alcohol used for polishing and cleaning, and the polishing and cleaning performance is inferior. There's a problem.
In addition, the split type composite fibers used in these are usually used as a matting agent used in general-purpose polyester fibers and polyamide fibers as a raw material with a resin containing not less than titanium dioxide. The titanium dioxide may damage the glass surface when it is precisely polished, particularly when it is used for a glass hard disk.

  In order to solve the above problem, for example, if the polyester resin of Patent Document 2 is used for the polyester of Patent Document 1, this polyester resin has an intrinsic viscosity subjected to solid phase polymerization treatment. It is a high polyester, and melting at a high temperature is necessary to melt spin this resin, and the polyamide used as the partner component of the composite fiber is denatured at a high temperature, making it difficult to perform composite spinning. .

  The object of the present invention is to solve the above-mentioned problems, and is suitable for polishing and cleaning that causes less oligomer elution and does not damage the hard disk surface when polished and cleaned as an abrasive cloth such as a glass hard disk. It is to provide a possible split type composite fiber.

The present inventors do not elute extra components during polishing and do not damage the disk surface. Therefore, the split-type composite fiber constituting the fabric does not contain a matting agent, and the cyclic trimer content in the polyester component Focusing on the use of a split type composite fiber in which polyamide is combined with the polyester having a reduced content, the present invention has been achieved.
That is, the present invention is a split type composite fiber comprising a polyester component and a polyamide component substantially free of titanium dioxide, wherein the cyclic trimer content in the polyester component is less than 1.0%. The gist is a split type composite fiber obtained by a production method in which the difference between the polyester-containing cyclic trimer after melt extrusion and the cyclic trimer of the polyester pellet is less than 0.3%.
Also, a method for producing a split-type composite fiber composed of a polyester component and a polyamide component, wherein the composite trim spinning is performed using a polyester chip having a cyclic trimer content of less than 1.0% in the polyester component, and melting. It is also a method for producing a split-type composite fiber, wherein the difference between the polyester-containing cyclic trimer after extrusion and the cyclic trimer of the polyester chip is less than 0.3%. In particular, it is preferable to perform melt composite spinning using a polyester chip obtained by subjecting the polyester chip after melt polycondensation to water washing with hot water and deactivating the polycondensation catalyst contained in the polyester.

  The split-type conjugate fiber of the present invention can be polished precisely without damaging the parts to be polished even when polishing a precision machine such as a hard disk. In addition, according to the production method of the present invention, when the split type composite fiber is produced, the occurrence of fluff and yarn breakage is reduced, so that the resulting product is inexpensive and has stable performance. Can do.

The present invention is described in detail below.
The present invention is a split type composite fiber in which a polyester component and a polyamide component are combined.

  As the polyester component, for example, polyester such as polyester ethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate can be used. Among these, it is preferable to use a polyester mainly composed of ethylene terephthalate.

  If necessary, the polyester may contain acid components such as sodium 5-sulfoisophthalate, adipic acid, sebacic acid, and isophthalic acid, and diol components such as diethylene glycol, triethylene glycol, polyethylene glycol, and cyclohexanedimethanol. By adopting a copolymer of three components, a desired function can be added. However, in order to reduce the content of oligomers such as a cyclic trimer, those that are not modified are preferable to polyesters modified by copolymerizing these third components.

The polyester is substantially free of titanium dioxide. Here, the phrase “substantially free of titanium dioxide” means that titanium dioxide is not actively added during polycondensation, and does not include a slight amount of contamination due to contamination. For example, it is less than 50 ppm when examined by a general ash content measurement method.
In this way, if the material does not substantially contain titanium dioxide, the surface is not damaged during hard disk polishing and cleaning.

  The content of the cyclic trimer of the polyester component is 1.0% or less. Within this range, the elution amount of the oligomer by the solvent used at the time of hard disk polishing cleaning is low, and it is possible to polish and clean precisely. Outside this range, the amount of oligomer elution is large and the eluted oligomer may damage or contaminate the disk surface. The term “cyclic trimer” as used herein refers to a precipitate of a cyclic oligomer that precipitates on the resin surface when polyethylene terephthalate is heated or exposed to a solvent vapor such as methylene chloride.

  The intrinsic viscosity of the polyester is not particularly limited, but is preferably in the range of 0.55 to 0.65. If it is in this range, it can be melted at a temperature suitable for composite spinning with polyamide, so that the cross-sectional shape is good and the spinning operability tends to be excellent.

  Moreover, it is preferable that the polyester is not subjected to solid phase polymerization treatment. This is because if a resin subjected to solid phase polymerization is used in the spinning process, it becomes necessary to melt and extrude at a high temperature, resulting in a large decrease in viscosity, resulting in poor spinning operability.

Next, the polyamide used for the polyamide component of the present invention is similar to the polyester,
It is substantially free of titanium dioxide. As a result, the disk surface is not damaged during hard disk polishing or cleaning.

  Examples of the polyamide include nylon 6, nylon 66, nylon 4, nylon 7, nylon 11, nylon 12, polymetaxylene adipamide, and the like. Of these, nylon 6 is preferred because of its versatility.

  And although the relative viscosity of the said polyamide is not specifically limited, 2.5-3.2 are preferable. If it is this range, it is suitable for a composite spinning with polyester, it is easy to keep a cross-sectional shape favorable, and it is easy to become excellent in spinning operability.

Next, the cross-sectional shape of the split-type conjugate fiber of the present invention is not particularly limited as long as it is a shape that is split and split after forming the fabric. As a suitable example, for example, if the single yarn fineness after split splitting is uniform, it is preferable in terms of excellent polishing performance and cleaning performance.
More specifically, for example, it is a split type composite fiber having a fiber cross-sectional shape having a composite form as shown in FIGS.

For example, if the one shown in FIG. 1 (a) and the one shown in FIG. 1 (d) are divided, thin fibers in which the two components are both flat can be obtained. Further, in the figure (b), the two components are alternately arranged as a large number of fan-shaped segments. In the figures (c), (g) and (j), the radial components (radial parts) ) And fan-shaped components (complementary parts that complement the radial parts). Further, those shown in (e), (h) and (i) are examples in which two components are arranged alternately in a ring and have hollow portions, and those shown in FIG. This is an example in which the components are combined alternately in the left-right direction. Further, the one shown in FIG. 6 (k) is an example of a two-component structure including a hollow radial component (radial portion), a circle complementing this hollow radial shape, and a trapezoidal component (complementary portion complementing the radial portion). . In addition to these, any composite form may be used as long as each part can be divided into segments.
Among them, the split type composite fiber composed of the radial portion shown in FIG. 1B and the complementary portion that complements the radial portion and the radial portion shown in FIGS. 1C, 1G, and 1J has a sharp edge. High polishing performance and cleaning performance are preferable.

The fiber cross-sectional shape and a suitable polymer combination are illustrated.
First, as shown in FIGS. 1 (e) and 1 (h) and (i), the split type composite fiber in which polyester and polyamide are alternately arranged in a ring and have hollow portions, the polyamide is the inner layer. Since the polyester is easily exposed to the surface layer and has a bulge due to the difference in shrinkage between the respective polymers, the polishing cleaning effect is enhanced, which is preferable.
Furthermore, it is an ultrafine fiber multifilament derived from a split type composite fiber composed of a radial part shown in (c), (g), (j), and (k) and a complementary part that complements the radial part. Is a polyamide and the complementary part is polyester, the complementary part sinks in the inner layer, the radial part is easily exposed on the surface layer, and it has sufficient swelling due to the difference in shrinkage of each polymer, so polishing performance and cleaning performance are High and optimal.
Thus, combining polyester and polyamide, the fiber cross-sectional shape as shown in the same figure (c), (e), (g), (h), (i), (j), (k) is provided, Particularly preferred is a two-layered yarn in which the inner layer of one component sinks and the other one component is exposed on the surface after being divided, and is combined so as to be sufficiently swelled by division.

  Further, the single yarn fineness of the split type composite fiber is not particularly limited, but is preferably 0.5 to 5.0 dtex from the viewpoint of excellent spinning operability and suitable for polishing and cleaning. . Of these, 1.0 to 2.5 dtex is preferable.

  Next, the specific manufacturing method of the split type composite fiber of this invention is demonstrated. Slurry 1.02-1.8 mol of ethylene glycol with respect to terephthalic acid and its ester-forming component, and if necessary, add a heat stabilizer or a catalyst to carry out a polycondensation reaction to obtain a polyester chip.

  In this case, the polymerization catalyst is not particularly limited, and for example, germanium dioxide, antimony trioxide, titanium butoxide and the like can be used. In particular, germanium dioxide is preferred in view of the increasing hue of the resin and antimony-free demand.

  Next, this polyester chip is subjected to a precrystallization treatment. The treated polyester chip is then contacted with hot water to remove the cyclic trimer. When contacting with hot water, a continuous or batch-type hot water treatment apparatus can be used. The treatment conditions at this time are preferably contacted with hot water at 80 to 100 ° C. for about 3 hours in order to efficiently remove the cyclic trimer and prevent deterioration of the chip.

  Thereafter, a dehydration drying process is performed to obtain a hot water-treated polyester chip.

  Next, the polyester chip is dried to a moisture content of 20 to 40 ppm.

  Thereafter, this polyester chip and a dried polyamide chip such as nylon 6 are put into a composite spinning machine, each is melt-extruded by an extruder and guided to a spinning head, melted and discharged from a composite spinneret, wound up, A filament composed of the above-described split type composite fiber is obtained.

  Here, the spinning winding method is not particularly limited. For example, a conventional method in which an undrawn yarn is wound and then drawn in a drawing step, a POY-DT method in which the yarn is drawn without drawing after being drawn at a high speed, and then drawn, and then a direct spinning that combines the spinning and drawing steps. A stretching method or the like can be employed. Of these, the direct spinning drawing method is preferable from the viewpoint of production efficiency.

In order to make the cyclic trimer contained in the polyester component less than 1.0%, the polyester chip is preferably brought into contact with hot water after polycondensation as described above.
The temperature of the hot water at this time is not particularly limited, but is preferably 80 to 100 ° C. If it is this range, precipitation of the cyclic trimer from within a polyester resin will advance effectively, and the cleaning effect will be acquired more. More preferably, it is 90-98 degreeC. Moreover, although washing | cleaning time is not specifically limited, In order to reduce a cyclic trimer efficiently, about 2 to 5 hours are preferable.
By such hot water washing treatment, the polymerization catalyst contained in the polyester resin is deactivated, and the cyclic trimer is efficiently converted into the above range by preventing the cyclic trimer from increasing during melt spinning. It is assumed that it can be.
In addition, since the cyclic trimer does not precipitate on the spinneret, the spinning operability is improved and fluff is not generated, which is preferable.

Further, the difference between the content of the cyclic trimer in the polyester after the polyester component is melt-extruded in the spinning process and the content of the cyclic trimer in the polyester supplied to the melt spinning is less than 0.3%. Is preferable, and more preferably less than 0.2%.
If it is such a range, spinning operativity improves and generation | occurrence | production of the fluff of the obtained fiber can be suppressed. This is presumed that the polymerization catalyst contained in the polyester is deactivated and the cyclic trimer is not increased at the melt spinning stage, so that the spinning operability is improved and the generation of fluff is suppressed. The If it is not within this range, spun yarn breakage frequently occurs, and the obtained composite fiber has a lot of fluff, which may cause frequent yarn breakage at the weaving and knitting stage.

Next, an example of a process for producing an abrasive fabric using the split-type conjugate fiber of the present invention is shown below.
The split type composite fiber obtained as described above is woven or knitted to form a fabric, and then the polyester component and the polyamide component are mechanically or chemically divided.
Here, as a preferable dividing method, for example, when a split type composite fiber made of polyester and polyamide is swollen with benzyl alcohol and the polyamide is shrunk, a raised feeling suitable for polishing and cleaning can be obtained without unevenness. To preferred.
Another suitable dividing method is to perform false twisting with a false twisting machine to physically separate the polyester component and the polyamide component.

    In the case of a polishing fabric, the fabric can be cut into a suitable tape state to obtain a texture tape. Moreover, if it is a cleaning cloth, the shape of a cloth can be processed suitably.

  Hereinafter, the present invention will be described in more detail with reference to examples. The characteristic values in the following examples are measured by the following method.

(1) Intrinsic viscosity of polyester The intrinsic viscosity [η] was measured by an ordinary method using an automatic viscometer in a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio) at 20 ° C.

(2) Polyamide relative viscosity The relative viscosity ηrel was measured by an ordinary method using an Oswald Wald Viscometer in a sulfuric acid solvent at 20 ° C.

(3) Cyclic trimer content (CT)
After dissolving the polyester chip or the melt-extruded polyester resin in a hexafluoroisopropanol: chloroform = 1: 1 solution, acetonitrile is added to precipitate the polymer, and the filtrate is subjected to high performance liquid chromatography using methanol as the mobile phase. And quantified.
CT of the polyester chip after polycondensation was CT1, CT of the polyester chip after hot water treatment was CT2, and CT of the polyester resin after melt extrusion in the spinning process was CT3. The amount of CT contained in the split type composite fiber is represented by this CT3.

(4) Breaking strength / breaking elongation Using an autograph tensile tester (manufactured by Shimadzu Corporation), a tensile test was carried out until the fracture occurred with an initial length of 200 mm, a strain rate of 100% / min, and an initial load of 1/30 cN / dtex. The breaking strength and breaking elongation were determined.

(5) Spinning operability Evaluation was made with a spinning fullness ratio of 90% or more as ◯, a spinning less than 90% as Δ, and a spinning less than 80% as x.

(6) Wiping cloth performance A tape-shaped fabric was produced using the split type composite fiber as the weft, and polishing cleaning evaluation was performed. Evaluation was made with ○ for those with good performance and × for those that could not be used.

Example 1
Using germanium dioxide as a polymerization catalyst, a polyester chip having an intrinsic viscosity of 0.635 was obtained by a conventional direct continuous polymerization method without adding titanium dioxide. The cyclic trimer content (CT1) in the polyester chip was 1.20%. Next, this polyester chip was pre-crystallized and then subjected to hydrothermal treatment with hot water at 100 ° C. for 3 hours to obtain a polyester chip having a cyclic trimer content (CT2) of 0.88%. This polyester chip was dried to a moisture content of 20 ppm, melt extruded at 295 ° C., led to a spinneret, and the cyclic trimer content (CT3) of the discharged polymer was measured to be 0.86%. Was 0.02%.
On the other hand, a nylon 6 chip having a relative viscosity of 2.70 and a titanium dioxide content of 0% is melt extruded at 280 ° C. and joined with polyester in the spinneret to form the cross-sectional shape shown in FIG. Then, 56 dtex / 25 f split-type composite fiber filaments were wound up by a direct spinning drawing method.
Table 1 shows the breaking strength, elongation, spinning operability, and fluff generation state of the obtained split composite fibers.
Next, this composite fiber was used as a weft and weaved using a 84 dtex / 36 f polyester fiber manufactured from the above-mentioned polyester chip as a warp to obtain a wiping cloth fabric.
This fabric was chemically treated to divide the polyester component and the nylon component to obtain a tape-like high-density microfiber fabric. When the obtained cloth was impregnated with isopropyl alcohol and the glass sheet was wiped off and the amount of white powder deposited, the wiping cloth performance was evaluated.

(Example 2)
Split type conjugate fibers were obtained in the same manner as in Example 1 except that the polyester chips shown in Table 1 were used and a 122 dtex / 100 f conjugate fiber was spun. As shown in Table 1, the performance and physical properties of this split type composite fiber were good.

(Example 3)
Using the polyester chips described in Table 1, 122 dtex / 100 f split-type composite fiber filaments were spun. The content (CT3) of the cyclic trimer of the obtained split type composite fiber is within the scope of the present invention, and precise polishing was possible without damaging the parts to be polished. However, since the difference between the cyclic trimer content after melt extrusion (CT3) and the cyclic trimer content after hot water treatment (CT2) exceeds 0.3%, fluff is likely to occur slightly. Although spinning was possible, the spinning operability was inferior to those of Examples 1 and 2.
In Comparative Example 2, CT3 was large and the wiping cross performance was poor.
(Comparative Example 1)
Using the polyester chips shown in Table 1, 122 dtex / 100 f split-type composite fiber filaments were spun. The composite fiber filament was fuzzy and had poor spinning operability. Comparative Example 1 was inferior in wiping cloth performance because CT3 was large and the object could be damaged.

(Comparative Examples 2 and 3)
In Comparative Example 2, the same polyamide component as in Example 3 was used, and a polyester chip containing 0.032% titanium dioxide in the polyester component was used.
Comparative Example 3 uses the same polyester component as in Example 3, and uses a nylon component having a titanium dioxide content of 0.21% and a relative viscosity of 2.90 as a polyamide component, and a 56 dtex / 25 f split-type composite. Fiber filaments were spun.
In either case, there was no problem in the spinning operability and the occurrence of fluff, but since it contained titanium dioxide, polishing the glass hard disk with high precision damages the surface of the hard disk, which was unsuitable.

Example 4
Example 1 except that a polyester chip having an intrinsic viscosity [η] of 0.635 before hydrothermal treatment was subjected to solid phase polymerization and then subjected to hydrothermal treatment, and the melt extrusion temperature of the polyester component was set to 305 ° C. In the same manner as above, split-type composite fiber filaments were spun. Although spinning was possible, since the spinning temperature of the polyester component was high, deterioration of the nylon 6 component occurred, and the spinning operability was inferior compared to Examples 1-3.

The example of the fiber cross-sectional shape of the split type composite fiber of this invention is shown.

Claims (3)

A split type composite fiber comprising a polyester component and a polyamide component substantially free of titanium dioxide, and a cyclic trimer content in the polyester component of less than 1.0%. A method for producing a split type composite fiber comprising a polyester component and a polyamide component, after melt compound spinning using a polyester chip having a cyclic trimer content of less than 1.0% in the polyester component and after melt extrusion The difference between the polyester-containing cyclic trimer and the cyclic trimer of the polyester chip is less than 0.3%. 3. The split die according to claim 2, wherein the polyester chip after the melt polycondensation is washed with hot water, and melt compound spinning is performed using the polyester chip in which the polycondensation catalyst contained in the polyester is deactivated. A method for producing a composite fiber.

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