HK1112269B - Polyvinyl chloride fiber with excellent style changeability - Google Patents

Description

Polyvinyl chloride fiber with excellent style changeability

Technical Field

The present invention relates to a polyvinyl chloride fiber excellent in touch, matting property and pattern change property.

Background

Polyvinyl chloride fibers obtained by extrusion-spinning a polyvinyl chloride resin have excellent strength, elongation, curl retention, dullness, touch feeling, and the like, and are used in large amounts as fibers for artificial hair such as hair decoration. Patent document 1 proposes a polyvinyl chloride fiber produced from a composition containing a matting agent, such as a polyvinyl chloride resin and a crosslinked polyvinyl chloride resin, and discloses that the fiber has excellent touch and appearance (matting property). However, the fibers do not have a possibility of sufficient pattern change (property of changing the wig or the like into various patterns by a brush, a comb, or the like, hereinafter referred to as pattern adjustability).

Patent document 2 proposes an artificial hair fiber having protrusions in the fiber axis direction on the fiber surface and the protrusions having recesses and protrusions, and discloses that an artificial hair product such as a wig using the fiber has excellent style adjustability (style array). However, patent document 2 does not specifically disclose a polyvinyl chloride resin. In addition, Japanese patent application laid-open No. 55-76102 discloses a fiber having a fiber cross section with protrusions in the radial direction. In this patent it is also disclosed that the fibres can suitably be used in wigs. However, the crosslinked polyvinyl chloride-based resin and the style-adjusting property are not mentioned in the patent.

Patent document 1: japanese unexamined patent publication No. 11-50330

Patent document 2: japanese patent laid-open publication No. 56-63006

Disclosure of Invention

The invention provides a polyvinyl chloride fiber containing a crosslinked polyvinyl chloride resin, which maintains the characteristics of the polyvinyl chloride fiber containing the crosslinked polyvinyl chloride resin, such as matting property and touch, and improves the style adjustment property.

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that the above objects can be achieved by controlling the fiber surface roughness and the cross-sectional shape of a polyvinyl chloride fiber, thereby completing the present invention.

That is, the present invention relates to the following polyvinyl chloride-based fibers.

(1) A polyvinyl chloride fiber comprising a polyvinyl chloride resin composition containing (a) 100 parts by weight of a polyvinyl chloride resin and (b) 0.2 to 20 parts by weight of a crosslinked polyvinyl chloride resin having a tetrahydrofuran-insoluble component in a weight fraction of 18 to 45% and a tetrahydrofuran-soluble component having a viscosity average degree of polymerization of 500 to 1800, wherein the cross-sectional shape of the fiber is a combination of 2 or more circles, ellipses and parabolas.

(2) The polyvinyl chloride-based fiber according to item (1) above, wherein the cross-sectional shape of the fiber is a combination of 3 or more circles, ellipses, or parabolas.

(3) The polyvinyl chloride-based fiber according to item (1) above, wherein the cross-sectional shape of the fiber is a combination of 4 or more circles, ellipses, and parabolas.

(4) The polyvinyl chloride-based fiber according to the above (1), wherein the cross-sectional shape of the fiber has a short diameter

(A) And the ratio B/A of the major axis (B) is 1.2 to 2.0.

(5) The polyvinyl chloride-based fiber according to item (1) above, wherein the fiber has protrusions on the surface thereof, and the average major axis of the protrusions is 1 to 30 μm.

According to the polyvinyl chloride fiber of the present invention, a polyvinyl chloride fiber having improved design adjustability can be obtained while retaining the characteristics of crimp retention, matting property, touch and the like of conventional polyvinyl chloride fibers.

Drawings

FIG. 16 is a cross-sectional view of a fiber having a leaf-like shape and a 5-leaf-like shape (a short diameter (A) and a long diameter (B) in the cross-sectional view)

FIG. 26 is a sectional view of a leaf shape (formed by 12 circles)

FIG. 3 is a cross-sectional view showing the minor axis (A) and major axis (B) of the asymmetric cross-section

FIG. 4 photograph of Pattern (A) evaluated for Pattern-adjusting Properties

FIG. 5 photograph of the form (B) evaluated for style adjustability

FIG. 6 is a schematic view of pattern (A)

FIG. 7 is a schematic view of pattern (B)

Detailed Description

The polyvinyl chloride resin (a) used in the present invention is a homopolymer resin, which is a conventionally known homopolymer of vinyl chloride, or various conventionally known copolymer resins, and is not particularly limited. Representative examples of the copolymer resin include a copolymer resin of vinyl chloride and vinyl esters such as a vinyl chloride-vinyl acetate copolymer resin and a vinyl chloride-vinyl propionate copolymer resin, a copolymer resin of vinyl chloride and acrylic esters such as a vinyl chloride-butyl acrylate copolymer resin and a vinyl chloride-2-ethylhexyl acrylate copolymer resin, a copolymer resin of vinyl chloride and olefins such as a vinyl chloride-ethylene copolymer resin and a vinyl chloride-propylene copolymer resin, and a vinyl chloride-acrylonitrile copolymer resin. Examples of the preferable polyvinyl chloride resin include homopolymer resins, vinyl chloride-ethylene copolymer resins, and vinyl chloride-vinyl acetate copolymer resins, which are polymers of vinyl chloride alone. The content of the comonomer in the copolymer resin is not particularly limited, and may be determined depending on the molding processability of the fiber, the characteristics of the fiber, and the like.

The polyvinyl chloride resin used in the present invention preferably has a viscosity average degree of polymerization of 450 or more in order to obtain sufficient strength and heat resistance as fibers. In addition, the polymerization degree is preferably 1800 or less in order to safely produce fibers under an appropriate nozzle pressure. In order to achieve these moldability and fiber characteristics, it is particularly preferable that the viscosity average degree of polymerization is in the range of 650 to 1450 in the case of using a homopolymer resin of vinyl chloride. When a copolymer is used, the viscosity average degree of polymerization is particularly preferably in the range of 1000 to 1700, although it depends on the content of the comonomer. Further, the above viscosity average polymerization degree was calculated by dissolving 200mg of the resin in 50ml of nitrobenzene, measuring the specific viscosity of the polymer solution with an Ubbelohde type viscometer in a 30 ℃ thermostat, and according to JIS-K6721.

The polyvinyl chloride resin used in the present invention can be produced by emulsion polymerization, bulk polymerization, suspension polymerization, or the like. In view of initial colorability of the fiber, a polymer produced by suspension polymerization is preferable.

As the polyvinyl chloride resin used in the present invention, a chlorinated polyvinyl chloride resin may also be used. As the chlorinated polyvinyl chloride resin, it is preferable to use a polyvinyl chloride resin as a raw material, and react the polyvinyl chloride resin with chlorine so that the chlorine content is as high as 58 to 72%. Since chlorination improves the heat resistance of the resin, the use of chlorinated polyvinyl chloride resin has the effect of preventing thermal shrinkage of the fibers. The chlorinated polyvinyl chloride resin preferably has a viscosity average degree of polymerization (viscosity average degree of polymerization of the raw polyvinyl chloride resin) of 300 to 1100, and if the viscosity average degree of polymerization is less than 300, the effect of reducing the thermal shrinkage of the fiber is small, and the fiber has a slightly high shrinkage. Conversely, if the viscosity average polymerization degree exceeds 1100, the melt viscosity becomes high, and the nozzle pressure during spinning tends to become high, making safe handling difficult. The viscosity average polymerization degree is particularly preferably 500 to 900. When the content of chlorine is less than 58%, the effect of reducing the thermal shrinkage of the fiber is small, and when the content exceeds 72%, the melt viscosity tends to be high, which makes stable operation difficult, which is not preferable.

The chlorinated polyvinyl chloride resin is preferably used in combination with a polyvinyl chloride resin rather than alone, from the viewpoint of yarn breakage during spinning and coloring of yarn due to heat. Preferably, the chlorinated polyvinyl chloride resin is mixed in a ratio of 0 to 40 wt% with respect to 100 to 60 wt% of the polyvinyl chloride resin. When the content of the chlorinated polyvinyl chloride resin exceeds 40% by weight, yarn breakage is likely to occur during spinning.

The present invention uses a crosslinked polyvinyl chloride resin (b) having a tetrahydrofuran insoluble component weight fraction (gel fraction) of 18 to 45 wt% and a tetrahydrofuran soluble component viscosity average degree of polymerization of 500 to 1800. If the weight fraction of the tetrahydrofuran insoluble component is less than 18% by weight, the extinction of the fiber becomes insufficient, and the style-adjusting property tends to be poor. On the other hand, if the amount exceeds 45% by weight, the touch of the resulting fiber tends to be poor, and the spinnability tends to be poor. If the viscosity average degree of polymerization of the tetrahydrofuran-soluble component is less than 500, the matting effect is insufficient and the style-adjusting property tends to deteriorate. On the other hand, if the melt viscosity exceeds 1800, the melt viscosity becomes high, and stable operation of the spinning step tends to be difficult.

The crosslinked polyvinyl chloride resin used in the present invention can be easily obtained by adding a polyfunctional monomer to vinyl chloride and polymerizing the monomer in suspension, microsuspension or emulsion polymerization in an aqueous medium. In this case, the polyfunctional monomer used is particularly preferably a diacrylate compound such as polyethylene glycol diacrylate or bisphenol a-modified diacrylate. The resin has a crosslinked structure and is a mixture of a gel fraction containing as a main component vinyl chloride insoluble in tetrahydrofuran and a polyvinyl chloride component soluble in tetrahydrofuran.

The weight fraction (gel fraction) of the tetrahydrofuran insoluble component was measured by the following method. 1g of a crosslinked polyvinyl chloride-based resin was added to 60ml of tetrahydrofuran and left to stand for about 24 hours. The resin was then thoroughly dissolved with an ultrasonic cleaner. The insoluble fraction in the tetrahydrofuran solution was separated using an ultracentrifuge (3 ten thousand rpm. times.1 hour). Then, 60ml of tetrahydrofuran was added to the separated insoluble fraction, and the resin was sufficiently dissolved with an ultrasonic cleaner, and the insoluble fraction in the tetrahydrofuran solution was separated with an ultracentrifuge (3 ten thousand rpm. times.1 hour) and dried. The gel fraction was calculated by the following formula.

Gel fraction (%) (weight (g) of the insoluble fraction)/1 g × 100

The crosslinked polyvinyl chloride resin is preferably added in an amount of 0.2 to 20 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin. If the amount is less than 0.2 parts by weight, the resulting fibers will have reduced dulling and style-adjusting properties, which is not preferred. Further, if the amount exceeds 20 parts by weight, the spinnability and the touch of the obtained fiber are reduced, which is not preferable.

In the production of the polyvinyl chloride resin composition of the present invention, a heat stabilizer and a lubricant may be appropriately added. The heat stabilizer used in the present invention may be any conventionally known heat stabilizer, and among them, at least one heat stabilizer selected from tin-based heat stabilizers, Ca — Zn-based heat stabilizers, hydrotalcite-based heat stabilizers, epoxy-based heat stabilizers, and β -diketone-based heat stabilizers is preferable. The heat stabilizer is preferably used in an amount of 0.2 to 5 parts by weight, more preferably 1 to 3 parts by weight. If the amount is less than 0.2 part by weight, the effect as a heat stabilizer is poor. Even if the amount exceeds 5 parts by weight, the thermal stability cannot be greatly improved, and this is economically disadvantageous.

Since the thermal decomposition of the resin during spinning can be prevented by adding the above-mentioned thermal stabilizer, the effect of enabling stable spinning (long-term spinnability) without lowering the color tone of the fiber is exhibited. The long-term spinnability is a property that the spinning process can be stably and continuously operated for several days without stopping, and fiber production can be performed. In the resin composition having a low long-term spinnability, for example, filament breakage starts to occur due to precipitation or the like within a relatively short time after the start of operation, and the molding starts to rise, so that it is necessary to replace a breaker plate (breaker plate) or a nozzle and restart the operation, and the production efficiency is poor. The decrease in the color tone of the fiber means initial coloration of the fiber during spinning.

Among the heat stabilizers, tin-mercapto stabilizers such as dimethyltin mercaptide, dibutyltin mercaptide, dioctyltin mercaptide polymer and dioctyltin thioglycolate; tin maleate-based heat stabilizers such as dimethyltin maleate, dibutyltin maleate, dioctyltin maleate and dioctyltin maleate polymers; tin laurate-based heat stabilizers such as dimethyltin laurate, dibutyltin laurate and dioctyltin laurate. Examples of Ca-Zn based heat stabilizers include zinc stearate, calcium stearate, zinc 12-hydroxystearate, calcium 12-hydroxystearate and the like. As the hydrotalcite-based heat stabilizer, there are ALCAMIZER and the like manufactured by Kyowa chemical industries Co. Examples of the epoxy heat stabilizer include epoxidized soybean oil and epoxidized linseed oil. Examples of the β diketone heat stabilizer include Stearoylbenzoylmethane (SBM) and Dibenzoylmethane (DBM).

The lubricant used in the present invention may be any conventionally known lubricant, but is preferably at least one selected from a metal soap lubricant, a polyethylene lubricant, a higher fatty acid lubricant, an ester lubricant, and a higher alcohol lubricant. This lubricant is effective for controlling the molten state of the composition and the adhesion state of the composition to the metal surface of a screw, a cylinder, a die, or the like in an extruder. The lubricant is preferably used in an amount of 0.2 to 5.0 parts by weight based on 100 parts by weight of the polyvinyl chloride resin. More preferably 1 to 4 parts by weight. If the amount is less than 0.2 parts by weight, the productivity will be reduced due to the increase in molding pressure and the decrease in discharge amount during spinning, and the yarn breakage, the increase in nozzle pressure, and the like will be liable to occur, making it difficult to stabilize the production. If the amount is more than 5 parts by weight, the discharge amount is decreased, the yarn breakage frequently occurs, and the like, and it is difficult to stably produce the fiber in the same manner as when the amount is less than 0.2 parts by weight, and the fiber having a transparent feeling tends not to be obtained, which is not preferable.

Examples of the metal soap lubricant include metal soaps such as stearates, laurates, hexadecanoates, and oleates of Na, Mg, Al, Ca, and Ba. Examples of the higher fatty acid-based lubricant include saturated fatty acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and capric acid, unsaturated fatty acids such as oleic acid, and mixtures thereof. Examples of the higher alcohol-based lubricant include stearyl alcohol, cetyl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohol. Examples of the ester lubricant include ester lubricants formed from an alcohol and a fatty acid, pentaerythritol lubricants formed from a mono-ester, a di-ester, a tri-ester, a tetra-ester of pentaerythritol or dipentaerythritol and a higher fatty acid, or a mixture thereof, and octacosanoic acid paraffin lubricants formed from esters of octacosanoic acid and a higher alcohol such as stearyl alcohol, cetyl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohol.

In the production of the polyvinyl chloride-based fiber of the present invention, for example, a processing aid, a matting agent, a filler, a plasticizer, an ultraviolet absorber, an antioxidant, an antistatic agent, a flame retardant, a pigment, and the like may be used as necessary.

Among them, as shown in patent document 1, in order to further improve the quality, it is more preferable to add an ethylene-vinyl acetate (EVA) resin for obtaining a soft touch, such as PES-250 manufactured by Nippon Unicar, and an acrylic resin for further improving the extrusion processability, such as PA-20 manufactured by KANEKA.

The cross-sectional shape of the polyvinyl chloride fiber of the present invention has a shape in which 2 or more circles, ellipses, and parabolas are combined, and is essential for exhibiting the effects of the present invention. As typical examples of the cross-sectional shape, a star shape (5-leaf shape) having 5 protrusions and a shape (6-leaf shape) having 6 protrusions are given as shown in fig. 1. In the present invention, a cross section having N protrusions is also referred to as an N-lobe cross section. For example, as shown in fig. 2, the 6-leaf-shaped cross section has a cross-sectional shape formed by combining 6 large circles and 6 small circles. In the sectional shape of fig. 2, the 6 large circles and the 6 small circles each have the same radius and assume a symmetrical shape, but the same radius is not essential. Of course, one of the 6 protruding parts of the 6-leaf shaped cross section may be an ellipse or a parabola, or a combination of a circle, an ellipse and a parabola.

It is necessary that the protrusions in the fiber profile have a certain size. The area of the protrusion in the cross section calculated as follows is preferably 1/20 or more, more preferably 1/10 or more, and particularly preferably 1/5 or more, of the area of the maximum inscribed circle of the cross section. The protrusion having such an area in the fiber cross section is preferably 2 or more, more preferably 3 or more, and particularly preferably 4 or more. Most preferably 5 to 8.

(area calculating method)

In the cross section of the fiber, the area of a portion surrounded by a straight line connecting 2 minimum points on both sides of the protrusion and a curve forming the protrusion was defined as the area of the protrusion. However, the protrusion is not considered to have an area less than 1/20 of the inscribed circle area.

As shown in fig. 1, the minor axis a of the cross-sectional shape in the present invention represents the diameter of the inscribed circle of the cross-sectional shape, and the major axis B represents the diameter of the circumscribed circle of the cross-sectional shape. In the case of the asymmetric cross-sectional shape shown in fig. 3, the diameter of the largest inscribed circle is defined as a, and the diameter of the smallest circumscribed circle is defined as B. The ratio of B/A is preferably 1.2 or more from the viewpoint of the pattern-adjusting property and the matting property, and the ratio of B/A is preferably 2.0 or less from the viewpoint of the spinning property, the touch and the pattern-adjusting property. Further, if the ratio of B/A is 1.2 to 2.0, the style adjustment can be also exhibited by mixing several kinds of monofilaments having a cross-sectional shape, for example, 10 monofilaments (ten filaments) having a 5-leaf-shaped cross-section and 10 monofilaments having a 6-leaf-shaped cross-section. In the case of the asymmetrical cross-sectional shape of fig. 3, it is more preferable that the ratio of B/a is 1.2 to 2.0 when the diameter of the smallest circumscribed circle is B, the center thereof is P, and the diameter of an inscribed circle centered on P is a as shown in fig. 3.

The polyvinyl chloride fiber of the present invention has irregular convex shapes (protrusions) on the side surfaces, and the average length and diameter of the convex shapes is preferably 1 to 30 μm. If the average value of the major axes of the convex shapes is less than 1 μm, the pattern adjustability is reduced, and if it exceeds 30 μm, the touch feeling is reduced. The crosslinked polyvinyl chloride resin has a high tetrahydrofuran insoluble gel fraction, and the fibers tend to have a large convex shape. The convex shape obtained by ordinary melt spinning is almost a cone composed of a smooth curve (in some cases, a pyramid is formed), and the height is almost 30 μm or less.

The polyvinyl chloride-based fiber of the present invention is produced by a known melt spinning method. For example, the polyvinyl chloride resin (a), the crosslinked polyvinyl chloride resin (b), the heat stabilizer and the lubricant are mixed at a predetermined ratio, stirred and mixed by a henschel mixer or the like, and then filled into an extruder, and the resin is extruded under good spinnability conditions at a barrel temperature of 150 to 190 ℃ and a nozzle temperature of 180 ± 15 ℃ to perform melt spinning.

The extruded monofilament is subjected to a heat treatment for about 0.5 to 1.5 seconds in a heated spinning tube (under conditions of good spinnability in an atmosphere of 200 to 300 ℃) provided immediately below the nozzle, and the produced undrawn yarn is sent to a drawing step by a drawing roll. The undrawn yarn was then passed through a hot air circulation box adjusted to a temperature of 110 ℃ between a drawing roll and a stretching roll to be stretched 3 times. Then, the fiber of the present invention is produced by drawing between 2 pairs of conical rolls installed in a hot air circulating box adjusted to a temperature of 110 to 135 ℃, continuously performing a relaxation treatment of about 25 to 40%, and winding the multifilament.

In order to stabilize the process in the production of the fiber, it is preferable to add an oil agent to the fiber. As the finish oil, a blend of a flatting agent, a surfactant, an antistatic agent, and the like, which is generally used in the production of fibers, can be used. The amount of the oil agent added is preferably: the amount of the oil is 0.1 to 0.3 wt% based on the net content of the oil in the final fiber product. When the amount is 0.1% by weight or less, static electricity is generated during the production of the fiber, making stable production difficult, and the surface of the fiber product tends to be rough (not smooth). On the other hand, if the amount exceeds 0.3% by weight, the surface of the fiber product becomes sticky, which is not preferable.

The polyvinyl chloride resin composition used in the present invention is preferably used as a powder mixture obtained by mixing the components using a conventionally known mixer such as a Henschel mixer, a super mixer, a ribbon blender or the like, or a pellet mixture obtained by melt-mixing the components. The powder mixture may be produced by hot mixing or cold mixing, and the production conditions may be those that are usual. In order to reduce the volatile content in the composition, it is particularly preferable to use thermal mixing in which the cutting temperature (cut temperature) during mixing is increased to 105 to 155 ℃. The pellet mixture can be produced by the same method as that for producing a usual vinyl chloride-based pellet mixture. For example, a mixer such as a single-screw extruder, a counter-screw extruder, a conical twin-screw extruder, a co-screw extruder, a kneading extruder, a planetary gear extruder, or a roll mixer can be used to form the pellet mixture. The conditions for producing the pellet mixture are not particularly limited, but the resin temperature is preferably 185 ℃ or lower in order to prevent thermal degradation of the polyvinyl chloride resin. In addition, a fine stainless mesh or the like may be provided in the kneading machine in order to remove foreign matter such as metal pieces of a cleaning tool such as a metal brush which may be mixed into the pellet mixture. The pellets can be produced by cold cutting (coldcut). A means of removing "cutting powder" (fine powder generated during production of particles) and the like that may be mixed in cold cutting may be employed, but a hot cutting method (houtcut) in which the mixing amount of "cutting powder" is small is preferably used.

In addition, when the polyvinyl chloride resin composition is formed into a fibrous undrawn yarn, a conventionally known extruder can be used. For example, a single-screw extruder, a counter-rotating twin-screw extruder, a conical twin-screw extruder, etc. can be used, but a single-screw extruder having a diameter of about 35 to 85mm Φ or a conical extruder having a diameter of about 35 to 50mm Φ is particularly preferable. If the diameter is too large, the extrusion amount becomes large, the nozzle pressure becomes too large, and the flow rate of the undrawn yarn becomes too high, which makes winding difficult, and is not preferable.

The polyvinyl chloride-based fiber of the present invention obtained as described above can be provided with a pattern-adjusting property without losing the characteristics of the conventional polyvinyl chloride-based fiber, i.e., the matting property and the touch. The reason why the polyvinyl chloride-based fiber having such characteristics can be obtained is not clear, but it is considered that the gel portion of the crosslinked polyvinyl chloride-based resin which is insoluble in melt spinning appears as a convex portion on the fiber surface, and when it exists on a specific fiber section, the entanglement of the yarn is greatly improved, and the style adjustment property which has not been achieved in the past is exhibited.

Examples

The following examples are intended to illustrate specific embodiments of the present invention in more detail, but the present invention is not limited to these examples.

(1) Evaluation of spinning Properties

In the melt spinning stage, the occurrence of yarn breakage was visually observed, and evaluation was performed in 4 stages as follows.

4: filament breakage for 1 time or less/1 hour

3: 2-3 times/1 hour of filament breakage

2: filament breakage for 4-6 times/1 hour

1: 6-15 times per 1 hour of filament breakage

(2) Extinction property

The fiber bundle after melt spinning was observed and evaluated in 4 stages as follows. When the matting property was evaluated, polyvinyl chloride fiber ADVANTAGE-R manufactured by KANEKA, Inc. was rated as class 3 (gloss disappeared).

4: severe loss of gloss

3: loss of gloss

2: slightly lustrous

1: has luster

(3) Tactile sensation

The fiber bundle after melt spinning was judged by touch and evaluated in 4 stages as follows. When the feel was judged, the polyvinyl chloride fiber ADVANTAGE-R manufactured by KANEKA was rated as class 4 (very soft and pliable).

4: is very soft and soft

3: is soft and pliable

2: is slightly hard

1: is very hard

(4) Pattern adjustability

A simple wig for evaluation was produced and evaluated as follows. The obtained fiber was cut into 25cm, and 2g of the cut fiber was uniformly laid on a straight line with a width of 10cm, and sewn to a cloth or the like with a sewing machine. 10 of the fiber assemblies were prepared at 1cm intervals in the longitudinal direction to prepare wigs for evaluation. The wig was wound around a metal tube having a diameter of 32mm, and was fixed in a drier set at a temperature of 95 ℃ for 1 hour to be curled. When the wig was changed from the style (A) shown in FIG. 4 to the style (B) shown in FIG. 5 with a brush, the ease of making the style was evaluated in the following 4 stages.

4: the pattern (A) can be changed into the pattern (B) after the brush is brushed for 2 times or less, and the pattern is very easy to control.

3: the pattern (A) can be changed into the pattern (B) 3-5 times by the brush, so that the pattern can be easily controlled.

2: it is necessary to brush more than 6 times to change from pattern (A) to pattern (B).

1: the pattern (A) cannot be changed into the pattern (B) no matter how many times the brush is made.

(5) Major and minor diameters of the cross-sectional shape

The diameter of the cross-sectional shape is measured by cutting the cross-section with a cutter or the like, observing 10 cross-sectional parts at 300 times with an SEM, measuring the longest diameter B and the shortest diameter A of the cross-section of the fiber, and calculating the average of the 10.

(6) Diameter of convex shape of fiber surface

The fiber surface was observed at 1000 times magnification by SEM, 10 convex portions were selected, the longest diameter of the 10 convex portions was measured, and the average of the 10 was calculated.

(examples 1 to 9 and comparative examples 1 to 5)

The polyvinyl chloride resin, the partially crosslinked polyvinyl chloride resin, the stabilizer, the lubricant, and the additive were mixed in a predetermined ratio shown in table 1, and stirred in a henschel mixer to prepare a mixture. As the EVA resin, PES-250 manufactured by Nippon Unicar Co., Ltd was used, and PA-20 manufactured by KANEKA, Ltd was used as a processing aid. In addition, in all examples and comparative examples, except for those shown in Table 1, 0.5 part by weight of EW-100 manufactured by Riken Vitamin K.K., and 0.5 part by weight of HW400P manufactured by Mitsui chemical Co., Ltd. The cross section of the hole is 0.1mm²And a nozzle having 120 holes was mounted on an extruder having a diameter of 30mm, and the mixture was extruded and melt-spun at a barrel temperature of 140 to 190 ℃ and a nozzle temperature of 180 + -15 ℃ under conditions of good spinnability. The extruded monofilament is heat-treated in a heating spinning cylinder (under conditions of good spinnability in an atmosphere of 200 to 300 ℃) provided just below the nozzle for 0.5 to 1.5 seconds, and the produced undrawn yarn is sent to a drawing step by a drawing roll. An oil solution was added to the undrawn yarn just before the take-off roll so that the weight fraction of the net content of the oil solution was 0.2 wt% based on the weight of the final product. Then, the undrawn yarn was drawn by 3 times through a hot air circulation box at 110 ℃ between a drawing roll and a stretching roll. Then, the resultant was stretched between 2 pairs of conical rolls placed in a box adjusted to 110 ℃ to continuously conduct 35% relaxation treatment, and the filament fineness of the wound filaments was 70 dtex ((detx) multifilament. The processability (spinnability) and the physical properties of the obtained multifilament were evaluated by the methods described above, and the results are shown in table 1.

Comparative example 1 a fiber was manufactured in exactly the same manner as in example 1, except that the kind of the partially crosslinked polyvinyl chloride was different. It is found that when the gel fraction of the crosslinked polyvinyl chloride is less than 18%, the surface roughness becomes small, the pattern controllability is greatly lowered, and the matting property is also lowered.

Comparative example 2 was manufactured in exactly the same manner as in example 1, except that the kind of the partially crosslinked polyvinyl chloride was different. When the gel fraction of the crosslinked polyvinyl chloride is higher than 45%, the surface convex shape becomes large, and the spinnability and touch are reduced, which is not preferable.

Comparative example 3 a fiber was manufactured in exactly the same manner as in example 1, except that partially crosslinked polyvinyl chloride was not added. In this case, the extinction property and the pattern adjustability were very poor as in comparative example 1.

Comparative example 4 a fiber was manufactured in exactly the same manner as in example 1, except that 25 parts of partially crosslinked polyvinyl chloride was added. In this case, spinning property and touch are not preferable.

Comparative example 5 produced a fiber in exactly the same manner as in example 1, except that the cross-sectional shape was circular. In this case, the extinction property and the pattern adjustability tend to be deteriorated.

As is clear from the results in table 1, the polyvinyl chloride-based fibers having the following characteristics have not only the matting properties, touch and the like which are the characteristics of the conventional polyvinyl chloride-based fibers but also excellent pattern adjustability. The polyvinyl chloride fiber is composed of a polyvinyl chloride resin composition obtained by mixing (a) 100 parts by weight of a polyvinyl chloride resin with (b) 0.2-20 parts by weight of a crosslinked polyvinyl chloride resin having a tetrahydrofuran-insoluble weight fraction of 18-45% and a tetrahydrofuran-soluble component having a viscosity average polymerization degree of 500-1800, and has a cross-sectional shape of a combination of 2 or more circles, ellipses and parabolas.

When the fiber of the present invention having a specific cross-sectional shape is used as artificial hair, the fiber can be provided with style-adjusting properties without losing the matting properties and touch of the polyvinyl chloride fiber. The fiber of the present invention can be produced by stable melt spinning, and therefore, is industrially advantageous.

Claims (22)

1. A polyvinyl chloride fiber comprising a polyvinyl chloride resin composition containing (a) 100 parts by weight of a polyvinyl chloride resin and (b) 0.2 to 20 parts by weight of a crosslinked polyvinyl chloride resin having a weight fraction of a component insoluble in tetrahydrofuran of 18 to 45% and a viscosity average degree of polymerization of the component soluble in tetrahydrofuran of 500 to 1800, wherein the cross-sectional shape of the fiber is a combination of 2 or more circles, ellipses and parabolas.

2. The polyvinyl chloride-based fiber according to claim 1, wherein the cross-sectional shape of the fiber is a combination of 3 or more circles, ellipses, or parabolas.

3. The polyvinyl chloride-based fiber according to claim 1, wherein the cross-sectional shape of the fiber is a combination of 4 or more circles, ellipses, or parabolas.

4. The polyvinyl chloride-based fiber according to claim 1, wherein a ratio B/A of a short diameter (A) to a long diameter (B) of a cross-sectional shape of the fiber is 1.2 to 2.0.

5. The polyvinyl chloride-based fiber according to claim 1, wherein said fiber surface further comprises protrusions, and the average major diameter of said protrusions is 1 to 30 μm.

6. The polyvinyl chloride-based fiber according to any one of claims 1 to 5, wherein the cross-sectional shape of the fiber is star-shaped and has 5 or 6 protrusions.

7. The polyvinyl chloride-based fiber according to any one of claims 1 to 5, wherein the cross-sectional shape of the fiber is: when the area of a portion surrounded by a straight line connecting 2 minimum points on both sides of the protrusion and a curve forming the protrusion is set as the area of the protrusion, the area of the protrusion is not less than 1/20 of the maximum inscribed circle area of the cross section.

8. The polyvinyl chloride-based fiber according to claim 6, wherein the cross-sectional shape of the fiber is: when the area of a portion surrounded by a straight line connecting 2 minimum points on both sides of the protrusion and a curve forming the protrusion is set as the area of the protrusion, the area of the protrusion is not less than 1/20 of the maximum inscribed circle area of the cross section.

9. The polyvinyl chloride-based fiber according to claim 1, wherein the polyvinyl chloride-based resin (a) is a homopolymer resin which is a single polymer of vinyl chloride, or a copolymer resin of vinyl chloride and a vinyl ester, a copolymer resin of vinyl chloride and an acrylate, a copolymer resin of vinyl chloride and an olefin, or a vinyl chloride-acrylonitrile copolymer resin.

10. The polyvinyl chloride-based fiber according to claim 9, wherein the copolymer resin is at least one copolymer selected from the group consisting of a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-vinyl propionate copolymer resin, a vinyl chloride-butyl acrylate copolymer resin, a vinyl chloride-2-ethylhexyl acrylate copolymer resin, a vinyl chloride-ethylene copolymer resin, a vinyl chloride-propylene copolymer resin, and a vinyl chloride-acrylonitrile copolymer resin.

11. The polyvinyl chloride-based fiber according to claim 1, wherein a chlorinated polyvinyl chloride-based resin is further mixed at a ratio of 0 to 40 wt% with respect to 100 to 60 wt% of the polyvinyl chloride-based resin.

12. The polyvinyl chloride-based fiber according to claim 1, wherein the polyvinyl chloride-based resin is a chlorinated polyvinyl chloride-based resin having a chlorine content of 58 to 72%.

13. A polyvinyl chloride-based fiber according to claim 1, wherein at least one heat stabilizer selected from the group consisting of a tin-based heat stabilizer, a Ca-Zn-based heat stabilizer, a hydrotalcite-based heat stabilizer, an epoxy-based heat stabilizer and a β -diketone-based heat stabilizer is added to said polyvinyl chloride-based resin composition.

14. The polyvinyl chloride-based fiber according to claim 1, wherein at least one lubricant selected from the group consisting of a metal soap-based lubricant, a polyethylene-based lubricant, a higher fatty acid-based lubricant, an ester-based lubricant and a higher alcohol-based lubricant is added to the polyvinyl chloride-based resin composition.

15. The polyvinyl chloride-based fiber according to claim 14, wherein the lubricant is added in an amount of 0.2 to 5.0 parts by weight based on 100 parts by weight of the polyvinyl chloride-based resin.

16. The polyvinyl chloride-based fiber according to claim 1, wherein an ethylene-vinyl acetate-based resin is further added to the polyvinyl chloride-based resin composition.

17. The polyvinyl chloride-based fiber according to claim 1, wherein an acrylic resin is added to the polyvinyl chloride-based resin composition.

18. The polyvinyl chloride-based fiber according to claim 1, wherein the polyvinyl chloride-based resin has a viscosity average degree of polymerization of 450 to 1800.

19. The polyvinyl chloride-based fiber according to any one of claims 1 to 5 and 9 to 18, wherein the polyvinyl chloride-based fiber is a fiber for artificial hair.

20. The polyvinyl chloride-based fiber according to claim 6, wherein the polyvinyl chloride-based fiber is a fiber for artificial hair.

21. The polyvinyl chloride-based fiber according to claim 7, wherein the polyvinyl chloride-based fiber is a fiber for artificial hair.

22. The polyvinyl chloride-based fiber according to claim 8, wherein the polyvinyl chloride-based fiber is a fiber for artificial hair.