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(ll) Patent Number: KE 384

(51)lnt.Cl.7:   

(73)0Wner:A 410 3/00, 0 OIF 6/48    KANEKA CORPORATION of , 2-4 Nllkanoshima. 3-chome Kita-ku, Osaka-shi Osaka 530-&28&, Jap:m

(ll) Application Nnmber:KEJPI 2007/000637   

(7l) Iuventor:ADACHI, Masayuki

(ll)FllingDa.te:23/02/2006   

(74) Agent/address for correspondence: Hamilton  HlllTi.SOn & Mathews,  P. 0. Box 30333-00lOO,Nairobi

(30)Priorttydata:    2005-060763  0410312005  JP   

(86) PCT data  PCT/JP2006/3032 2310212006 wo 2006/093009 08109/2006

(54) Tide: POLYVINYL CHLORIDE FIBER WITH EXCELLENT STYLE CHANGEABILITY

(57)    Abstnd: inyl chloride fibres obtained by subjecting a vinyl chloride resin for fibres to extrusion spinning are excellent in strength,
elongation, curl retention. matte properties, touch feeling. etc. and are used in large qwmtities as fibers for artificial hair for hair decoration, etc. However, such conventional vinyl chloride fibers have not had sufficient style changeability. Provided w:e vinyl chloride fibtml made of a vinyl chloride resin composition which comprises (a) a vinyl chloride resin and (b) a crosslinked vinyl cll.loride resin. which has a tetrnhydrofuran insoluble content of I 8-45 wt% and in which the t<:trahhdrofuran soluble component has a viscosity-average degree of polymerization of 500-1,300, the fibers each having a specific sectional shape. These fibers, when used as artificial hair, can have style changeability while rettli.ning the intact matte properties and touch feeling inherent in vinyl chloride fibers. These fibers can be stably produced by melt spinning and are hence industrially advantageous..


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DESCRIPTION

POLYVINYL CHLORIDE-BASED FIBER WITH EXCELLENT STYLE

CHANGEABILITY

5

Technical Field

[0001] The present invention relates to a polyvinyl chloride-based fiber that is

excellent in touch, matte properties, and style changeability.

10    BackgroundArt

[0002] Polyvinyl chloride-based fibers produced by extrusion-spinning vinyl chloride resins are excellent in, for example, strength, elongation, curl retention, matte properties, and touch, and thus they are used widely as

fibers  for  artificial hair such  as hair  decoration.   Patent Document  1 has

15    proposed a polyvinyl chloride-based fiber produced from a composition that contains a vinyl chloride resin and a matting agent such as a crosslinked vinyl chloride resin. It has been disclosed that this fiber is excellent in touch and appearance (matte properties). However, this fiber is not sufficiently

provided with style changeability (properties with which wigs and the like

20    can be changed into various styles with, for example, a brush or a comb: hereinafter, referred to as "style chaogeability'').

[0003] Patent Document 2 has proposed a fiber for artificial hair, in which a surface of the fiber has projected lines in the axial direction of the fiber and the projected lines further have projections and indentations. It has been

25    disclosed that artificial hair products such as wigs using this fiber are excellent in style changeability. However, in Patent Document 2, there is no specific disclosure of a vinyl chloride resin. It should be noted that JP

S55•76102A  has  disclosed  a  fiber  in  which  the  fiber  cross  section  has

protrusions in the !'adial direction.   This patent document also has disclosed

30    that  this  fiber  preferably  can  be  used for  wigs.   However,  in  this  patent

document, there is no statement regarding a crosslinked vinyl chloride resin

or style changeability.

Patent Document 1: JP Hll•50330A

Patent Document 2: JP S56•63006A

5

Disclosure of Invention

Problem to be Solved by Invention

[0004] The present invention is to provide a polyvinyl chloride-based fiber containing a crosslinked vinyl chloride resin, in which style changeability has

10    been improved while matte properties, touch, and other characteristics of a fiber produced from a vinyl chloride resin containing a crosslinked vinyl chloride resin are kept.

Means for Solving Problem

15    [0005] The present inventors had conducted an in•depth study in order to solve the above-described problem, and found that the above-described object can be achieved by controlling the fiber surface roughness and the

cross-sectional shape of a polyvinyl chloride-based fiber, and thus the present

invention has been achieved.

20    [0006] More specifically, the present invention is directed to a polyvinyl chloride• based fiber below.

(1)    A polyvinyl chloride-based fiber, comprising a vinyl chloride resin composition that comprises (a) 100 parts by weight of vinyl chloride resin,

and (b) 0.2 to 20 parts by weight of crosslinked vinyl chloride resin in which a

25    weight fraction of constituents that are insoluble in tetrahydrofuran is 18 to

45% and a viscosity average degree of polymerization of constituents that are soluble in tetrahydrofuran is 500 to 1800, wherein a cross-sectional shape of the fiber comprises a combination of at least two of circles.

(2)    The   polyvinyl  chlol'ide•based  fiber   according   to   (1),   wherein   a

30    cross-sectional shape of the fiber comprises a combination of at least three of

circles, ellipses, and parabolas.

(3)    The   polyvinyl   chloride-based  fiber   accordmg   to   (1),   wherein   a

cross• sectional shape of the fiber comprises a combination of at least four of

circles, ellipses, and parabolas.

(4)    The polyvinyl chloride-based fiber according to (1), wherein a ratio BIA between a minor diameter (A) and a major diameter (B) of a cross-sectional shape of the fiber is 1.2 to 2.0.
(5)    The polyvinyl chloride-based fiber according to (1), wherein a surface of

the  fiber  has  protrusions,  and  an  average  longitudinal  length  of  the

10    protrusions is 1 ~ to 30 ~-

(6)    The  polyvinyl  chloride-based fiber  according  to  any  one  of (1)  to  (5),

wherein the cross• sectional shape of the fiber further comprises an ellipses or

a parabola in addition to the combination.

15    Effect ofinvention

[0007] According to the polyvinyl chloride• based fiber ofthe present invention, it is possible to obtam a polyvinyl chloride-based fiber in which style changeability has been improved while curl retention, matte properties, touch, and other characteristics of a conventional vinyl chloride• based fiber are kept.

20

Brief Description of Drawings

[0008]

FIG.  1 is  a cross•sectional  view  of a fiber with  a six-leaved cross

section and a five-leaved cross section (showing a minor diameter (A) and a

25    major diameter (B) of the cross-sectional shape).

FIG.  2  is  a  cross-sectional  view  with  a  six-leaved  cross  section

(constituted by 12 circles).

FIG. 3 shows a mino1• diameter (A) and a major diameter (B) of an

asymmetrical cross section.

30    FIG.  •l  is  a  photograph  of  a  style  (A)  in  evaluation  of  style

changeability.

FIG. 5 is a photograph of a style (B) in evaluation of style changeability.

FIG. 6 is a schematic view of the style W.

5    FIG. 7 is a schematic view of the style (B).

Best Mode for Carrying Out the Invention

[0009] A vinyl chloride resin (a) used in the present invention refers to homopolymer resins that are conventionally known vinyl chloride

10    homopolymers, or conventionally known various copolymer resins) and there is no specific limitation on this vinyl chloride resin (a). Representative examples of the copolymer resins include: copolymer resins of vinyl chloride and vinyl esters, such as a vinyl chloride I vinyl acetate copolymer resin, and a vinyl chloride I vinyl propionate copolymer resin; copolymer resins of vinyl

15    chloride and acrylic esters, such as a vinyl chloride I butyl acrylate copolymer resin, and a vinyl chloride I 2•ethylbexyl acrylate copolymer resin; copolymer resins of vinyl chloride and olefins, such as a vinyl chloride I ethylene

copolymer resin, and a vinyl chloride I propylene copolymer resin; and a vinyl

chloride  I  acrylonitrile  copolymer  resin.   Examples  of a  preferable  vinyl

20    chloride resin include a homopolymer resin that is a vinyl chloride homopolymer, a vinyl chloride I ethylene copolymer resin, and a vinyl chloride

I vinyl acetate copolymer resin. In the copolymer resins, there is no specific limitation on comonomer content, and it can be determined according to moldability into fibers, fiber properties, and the like.

25    [0010] The viscosity average degree of polymerization of the vinyl chloride resin used in the present invention preferably is 450 or more, in 01•der to achieve sufficient strength and sufficient thermal resistance as a fiber. Furthe1•more, in order to produce a fiber safely under proper nozzle pressure,

the degree of polymerization preferably is 1800 or less.   In order to achieve

30    moldability  and  fiber   properties,  in  a   case   where   a  vinyl  chloride


homopolymer resin is used,  the viscosity average degree of polymeriZation

particularly preferably is 650 to 1450. In a case where a copolymer is used, a paxticularly preferable viscosity average degree of polymerization is 1000 to

1700,  although it depends on the comonomer content.   It should be noted

5    that the viscosity average degree of polymerization is calculated following JIS•K6721, by dissolving 200 mg of resin in 50 ml of nitrobenzene, placing this polymer solution in a 3!rC constant temperature bath, and measuring the specific viscosity using an Ubbelohde viscometer.

(00 U] The vinyl chloride resin used in the present invention can be produced,

10    for example, by emulsion polymerization, block polymerization, or suspension polymerization. In view of, for example, initial coloring of the fiber, a polymer produced by suspension polymerization is preferable.

(0012] As the vinyl chloride resin used in the present invention, a chlorinated

vinyl chloride resin also may be used.   It is preferable to use a chlorinated

15    vinyl chloride resin in which a vinyl chloride resin is used as a raw material, and chlorine is reacted therewith, thereby increasing.the chlorine content to

58 to 72%.   When a resin is chlorinated, the thermal resistance of the resin

is improved, and  thus using a chlorinated vinyl chloride resin ptovides an

effect  of reducing  thermal  contraction  of a  fiber.   The  viscosity  average

20    degree of polymerization of the chlorinated vinyl chloride resin (the viscosity average degree of polymerization of the vinyl chloride resin serving as a raw material) preferably is 300 to 1100. If the viscosity average degree of

polyme1ization  is  less  than  300,  then  the  effect  of lowering  the  thermal

contraction  ratio  of  a  fiber  becomes  small,  and  thus  a  fiber  having  a

25    comparatively high contraction ratio is obtained. If the viscosity average degree of polymerization is more than 1100, then the melt viscosity becomes high, and thus the nozzle pressure dUlmg spinning becomes high, so that

petforming  a  safe  operation  tends  to  be  difficult.   The  viscosity  average

degree of polymerization particularly preferably is 500 to 900.   Furthmmore,

30    if the  chlmme  content  is  less  than  58%,  then  the  effect  of lowering  the

thermal contraction ratio of a fiber becomes small.   If the chlorine content is

more than 72%, then the melt viscosity becomes high, and thus performing

stable operation tends to be difficult.   Thus, such chlorine contents are not

preferable.

[0013] In view of yarn breaking during spinning or coloration of a yarn due to heat, using the chlorinated vinyl chloride resin in combination with a vinyl chloride resin is more preferable than using it alone. The chlorinated vinyl chloride resin preferably is mixed in a ratio of 0 to 40 wt% with respect to 100 to 60 wt% of the vinyl chloride resin. If the chlorinated vinyl chloride resin

10    is more than 40 wt%, then yarn breaking occurs more during spinning.

[0014] In the present invention, a crosslinked vinyl chloride resin (b) is used in which the weight fraction of constituents that are insoluble in

tetrahydrofuran  (gel fraction)  is 18  to  45 wt%,  and  the  viscosity  average

degree of polymerization of constituents that are soluble in tetrahydrofuran is

15    500 to 1800. If the weight fraction of constituents that are insoluble in tetrahydrofuran is less than 18 wt%, then the matte properties of the fiber

tend to be insufficient, and the style changeability also tends to be poor. If the weight fraction is more than 45 wt%, then the touch of the obtained fiber tends to be poor, and the spinnability also tends to be poor. Furthermore, if

20    the viscosity average degree of polymerization of constituents that are soluble in tetrahydrofuran is less than 500, then the matting effects tend to be insufficient, and the style changeability also tends to be poor. If the viscosity average degree of polymerization is more than 1800, then the melt viscosity becomes high, and thus performing stable operation in the spinning process

25    tends to be difficult.

[0015] The crosslinked vinyl chloride tesin used in the present invention easily can be obtained by perfotming polymerization while adding a polyfunctional monomer, during suspension polymerization, microsuspension
potymeli.zation, or emulsion polymerization of vinyl chloride in an aqueous

:30    medium.   Pru-ticulru•ly pt•eferable examples of the polyfunctional monomer

used at that time include diacrylate compounds such as polyethylene glycol diacrylate and bisphenol A-moilified diaCl•ylate. This resin has a crosslinked structure, and is a mixture of gels mainly constituted by vinyl chloride insoluble in tetrahydrofuran, and polyvinyl chloride constituents soluble in tetrahydrofuran.

[0016] The weight fraction of constituents that are insoluble in tetrahydrofuran (gel fraction) is measured in the following manner. First, 1 g of crosslinked vinyl chloride resin is added to 60 ml of tetrahydrofuran, and the mixture is allowed to stand for approximately 24 hours. Then, the

10    resin is dissolved sufficiently using an ultrasonic cleaner. Insoluble mattezs in the tetrahydrofuran solution are separated using an ultracentrifuge (30000 rpm x 1 hour). Then, another 60 ml of tetrahydrofuran is added to the

separated insoluble matters, and the resin is dissolved sufficiently using the

ultrasonic  cleaner.   Insoluble  matters in the  tetrahydrofuran  solution  are

15    separated using the ultracentrifuge (30000 rpm x 1 hour), and dried. The gel fraction is calculated by the following formula.

Gel fraction (%) =weight of the insoluble matters (g)/1 g x 100

The crosslinked vinyl chloride resin is added, preferably in an amount

of 0.2 to 20 parts by weight, and more preferably in an amount of 1 to 5 parts

20    by weight, with respect to 100 parts by weight of the vinyl chloride resin. If the amount is less than 0.2 parts by weight, then the matte properties and the style changeability of the obtained fiber are lowered, so that such an

amount is not preferable.   Furthermore, if the amount is m01•e than 20 parts

by  weight,  then  the  spinnability and  the  touch  of the  obtained fiber  are

25    lowered, so that such an amount is not preferable

[0017] During production of the vinyl chloride resin composition of the present invention, a the1•mal stabilizer and a lubricant may be added as
appropriate.    As  the  thermal  stabilizer  used  in  the  present  invention,

conventionally  known  thermal  stabilizers  can  be  used.   Of  these,  it  is

30    preferable  to  use  at least  one  type  of thermal stabilizer seleete<l from  the

group consisting of tin•based thermal stabilizers, Ca•Zn•based thermal stabilizers, hydrotalcite•based thermal stabilizers, epoxy•based thermal stabilizers, and P•cliketone•based thermal stabilizers. The thermal stabilizer is used preferably in an amount of 0.2 to 5 parts by weight and more

5    preferably in an amount of 1 to 3 parts by weight. If the amount is less than 0.2 parts by weight, then the effect as the thermal stabilizers is poor. Even
if the  amount is  more than 5 parts by weight, the thermal stability is not

significantly increased, and thus it is disadvantageous economically.

[0018]  When the thermal stabilizer is added,  thermal decomposition of the

10    resin during spinning is prevented, and thus an effect of preventing degradation of hues of the fiber, an effect of enabling spinning to be performed stably (iong•run spinnability), and other effects are exerted. The long•run spinnability refers to properties with which fibers can be produced by continuing the operation for several days stably without stopping the

15    spinning process. When a resin composition havlllg low long•run spinnability is used, within a comparatively short time after starting the operation, a yarn starts to be broken, for example, due to plate out, or die pressure starts to increase. Accordingly, it is necessary to replace breaker plates or nozzles, and then re•start the operation, and thus the production

20    efficiency is poor. The degradation of hues of the fiber described above refers to initial coloring of the fiber during spinning.

[0019] Of the thermal stabilizers, examples of the tin•based thermal stabilizers include: mercaptotin•based thermal stabilizers such as

dimethyltin    mercapto,   dimethyltin   mercaptide,   dibutyltin   mercapto,

25    dioctyltin mercapto, dioctyltin mercapto polymer, and dioctyltin mercapto acetate: maleatetin•based thermal stabilizers such as dimethyltin maleate, dibutyltin maleate, dioctyltin maleate, and dioctyltin maleate polymer: and

lauratetin•based thermal stabilizers such as dimethyltin laurate,  dibutyltin

laurate,  and  dioctyltin  laurate.    Examples  of  the  Ca•Zn•based  thermal

:30    stabilizers include zinc stearate, calcium stearate. zinc  12•hydToxystearate,

and  calcium  12-hydroxystearate.    Examples  of  the  hydrotalcite•based thermal stabilizers ioclude ALCAMIZER manufactured by Kyowa Chemical Industry Co., Ltd.   Examples of the epoxy• based thermal stabilizers ioclude epoxidized  soybean  oil  and  epoxidized  lioseed  oil.    Examples  of  the 5    ~-diketone•based thermal stabilizers ioclude stearoylbenzoylmethane (SBM)
and dibenzoylmethane (DBM).

[0020] As the lubricant used io the present iovention, conventionally known lubricants can be used. Of these, it is particularly preferable to use at least one type of lubricant selected from the group consisting of metal soap-based

10    lubricants, polyethylene-based lubricants, higher fatty acid-based lubricants, ester-based lubricants, and higher alcohol-based lubricants. The lubricant is effective for controlliog a molten state of the composition, and a bonded state

of the composition and a metal face such as screws, cylinders, or dies in an

extruder.    The lubricant is added preferably io an amount of 0.2 to 5.0 parts

15    by weight with respect to 100 parts by weight of the vinyl chloride resio. The lubricant is added more preferably io an amount of 1 to 4 parts by weight. If the amount is less than 0.2 parts by weight, then the production efficiency

is lowered because the die pressme is increased and the ejection amount is

lowered during spinning.   Moreover, yarns tend to be broken more often, and

20    the nozzle pressure tends to be increased more often, so that pe1forming stable production becomes difficult. If the amount is more than 5 parts by weight, then the ejection amount is lowered and yarns frequently are broken, for example, and thus performiog stable production becomes difficult as io

the case where the amount is less than 0.2 parts by weight.   Moreover, the

25    fiber tends not to be clear, so that such an amount is not preferable.

[0021] Examples of the metal soap-based lubricants ioclude metal sosps such as stearate, laurate, palmitate, and oleate of Na, Mg, AI, Ca, and Ba. Examples of the higher fatty acid-based lubricants ioclude: saturated fatty

acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and capdc

.30    acid;  unsaturated  fatty  acids  such  as  oleic  acid;  and  their  mixtures.
 

Examples of the higher alcohol•based lubricants include stearyl alcohol, palmityl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohoL Examples of the ester-based lubricants include: esterbased lubricant comprising alcohol and a fatty acid; pentaerythritol•based lubricants such as

5    monoester, diester, triester, tetraester, or their mixtures comprising pentaerythritol or dipentaerythritol, and a higher fatty acid; montanoic acid wax• based lubricants such as esters comprising a montanoic acid, and higher alcohol such as stearyl alcohol, palmityl alcohol, myristyl alcohol, Iaury!

alcohol, and oleyl alcohoL

10    [0022] During 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 anti-oxidant, an antistatic agent, a flame

retardant, and a pigment may be used according to the purpose.

[0023] Of these, as disclosed in Patent Document 1, more preferably added

15    are an ethylene I vinyl acetate (EVA) resin (e.g., PES•250 manufactured by Nippon Unicar Company Limited) for further improving the quality, more

specifically,  for  obtaining  soft  touch,  and  an  acrylic  resin  (e.g.,  PA-20

manufactured    by   KANEKA   CORPORATION)   for   further   improving

extrudability.

20    [0024] In order to exert the effect of the present invention, it is necessary for the polyvinyl chloride•based fiber of the present invention to have a cross•sectional shape constituted by a combination of two or more of circles, ellipses, and parabolas. Representative examples of the cross-sectional shape include the shape of a star having five projecting portions (five• leaved

25    cross•section) or six projecting portions (six-leaved cross section) as shown in

FIG. L In the present invention, a cross section having N projecting portions is also referTed to as an N •leaved cross section. For example, a six-leaved cross section xefers to a cross•sectional shape constituted by a

combination of six large circles and six small circles as shown in FIG. 2.   In

30    the cross•sectional shape in FIG. 2,  the six large circles  and the six small
 
circles respectively have the same radiuses and symmetrical shapes, but the

radiuses need not be the same.   It would be appreciated that one of the six

projecting portions on the six-leaved cross section may be in the shape of an

ellipse or a parabola, or that circles, ellipses, and parabolas may be used :in

5    combination.

[0025] It is necessary that the projecting portion on the fiber cross section has a certain level of size. The area of the projecting portion on the cross section calculated :in the follow:ing manner is preferably 1120 or more, more
preferably 1/10 or more, and particularly preferably 1/5 or more, with respect

10    to the area of the largest inscribed circle of the cross section. Furthermore, on the fiber cross section, the number of the projecting portions havirig such an area is preferably 2 or more, more preferably 3 or more, and particularly preferably 4 or more. The number is most preferably 5 to 8.
(Area calculating method)

15 On the fiher cross section, the area of a portion enclosed by a straight lirie connecting two local miriimum points on both sides of the projecting portion, and a curved line formirig the projecting portion, is taken as the area of the projecting portion. It should be noted that a portion with an area of less than 1120 of the area of an inscribed circle is not taken as a projecting

20    portion.

[0026] In the present invention, a minor diameter A of the cross•sectional shape refers to the diameter of an inscribed circle of the cross• sectional shape, and a major diameter B refers to the diameter of a circumscribed circle of the cross-sectional shape, as shown in FIG. 1. Furthermore, in the case of an

25    asymmetrical cross•sectional shape as shown in FIG. 3, the diameter of the largest inscribed circle is taken as A, and the diameter of the smallest circumscribed circle is taken as B. In view of style changeability and matte properties, the ratio B/A preferably is 1.2 or more. In view of spinnability,

touch, and style changeability, the ratio B/A preferably is 2.0 or less. 30 Furthermore, if the ratio B/A is 1.2 to 2.0, then the style changeability is
 
exerted even when filaments with some types of cross•secti.onals shapes, such

as  ten  filaments  with  five-leaved  cross  sections  and  ten  filaments  with

six-leaved  cross  sections,  are  mixed.    Furthermo1•e,  in  the  case  of  an

asymmetrical cross-sectional shape as shown in FIG. 3, when the diameter of

5    the smallest circumscribed circle is taken as B, the center of this circle is taken as P, and the diameter of an inscribed circle centered about Pis taken as A as shown in FIG. 3, the ratio B/Amore preferably is 1.2 to 2.0.
[0027]  Furthermore,  the  polyvinyl  chloride-based  fiber  of  the  present

invention preferably has projections (protrusions) on surface at random, and

10    an average longitudinal length of the projections preferably is 1 to 30 1-1m. If the average longitudinal length of the projections is less than 1 1-1m, then the style changeability is lowered. If the average longitudinal length is more than 30 lliD• then the touch is degraded. The projections on the tiber surface

tend to be large if the fraction of gels insoluble in tetrahydrofuran is high in

15    the crosslinked vinyl chloride resin. Projections obtained in ordinary melt-spinning are in most cases in the shape of circular cones formed by smooth curved lines (in rare cases, partially in the shape of pyramids), and have a height of 30 !-1ID or less in most cases.
[0028]  The polyvinyl  chloride-based fiber  of the present invention  can be

20    produced by a known melt-spinning method. For example, a vinyl chloride resin (a), a crosslinked vinyl chloride resin (b), a thermal stabilizer, and a lubricant are mixed in a predetermined ratio, and agitated and mixed using a Henschel mixer and the like, and then an extruder is filled with the mixture. This resin is melt extruded under conditions providing good spinnability at a

25    cylinder temperature of 150 to 190°C and a nozzle temperature of 180 ± 15°C. [0029] The extruded filaments are subjected to thermal treatment for approximately 0.5 to 1.5 seconds within a heat-spinning tube (200 to 300°C atmosphere, conditions providing good spinnability) provided directly under

the nozzle.   Then, the produced undra'\\r'TI yarns are sent by a take-in roll so

30    as to be subjected to a drawing process.   Next, the undrawn yatns are drawn

to three times between the take-in roll and a drawing roll through a hot air circulation chamber in which the temperature has been adjusted to l10°C.

Furthermore, the yarns are stretched between two pairs of circular cone rolls

arranged in the hot air circulation chamber in which the temperature has been adjusted to 110 to l35°C. Relaxation treatment at approximately 25 to

40% then is performed, and multifilaments are wound, and thus the fiber of

the present invention is produced.

[0030] In order to stabilize the process during production of the fiber, an oil preferably is added to the fiber. AB the oil, it is possible to use a mixture of a

10    smoothing agent, a surfactant, an antistatic agent, and the like commonly used during production of fibers. The oil preferably is added so as to be attached to the final fiber product in an oil net content of 0.1 to 0.3 wt%. If

the  ratio  is  less  than  0.1 wt%,  then  static  electricity  is  caused  during

production  of the  fiber,  and  thus  performing  stable  production  becomes

15    difficult, so that the surface of the fiber product tends to be rough <not smooth). If the ratio is more than 0.3 wt%, then the surface of the fiber product becomes sticky, so that such a ratio is not preferable.

[0031]  The vinyl chloride resin composition used in the present invention

preferably is  used  as:  a  powder compound mixed  using  a  conventionally

20    known mixer such. as a Henschel mixer, a super mixer, or a ribbon blender; or a pellet compound produced by melt•mising this powder compound. The powder compound can be produced by either hot blending or cold blending, and ordinary conditions can be applied as the production conditions. Hot blending particularly preferably is used in which the cut temperature during

25    blending is increased up to 105 to 155°C in order to reduce volatile matters in the composition. The pellet compound can be produced as in production of ordinru•y vinyl chlol"ide•based pellet compounds. For example, the pellet

compound can be produced using a kneader such as a single screw extruder, a

counter-rotating  twin  screw  extntder,  a  conical  twin  screw  extruder,  a


roll  kneader.   There  is  no  specific  limitation  on  the  condition  used  for

production of the pellet compound, but the resin temperature preferably is set to 185°C or lower in order to prevent the vinyl chloride resin from being

deteriorated by heat.   Furthermore, in order to remove foreign substances,

such as a metal piece of a cleaner such as a wire brush, that may be mixed in the pellet compound, a stainless steel mesh with a small opening may be provided in the kneader. A cold cutting method can be applied for production of the pellet. It is possible to apply means fox removing "chips" (fine powders generated during production of the pellet) and the like that

10    may be mixed in during the cold cutting. However, it is preferable to use a hot cutting method in which less "chips" are mixed in.

[0032] Furthermore, a conventionally known extruder can be used fox processing the vinyl chloride resin composition into fibrous undrawn yams.
For example, it is possible to use a single screw extruder, a counter-rotating

15    twin screw extruder, or a conical twin screw extruder. It is particula1:ly preferable to use a single screw extruder with an aperture lrize of approximately 35 to 85 mm<j>, or a conical extruder with an aperture lrize of

approximately  35  to  50  mm<j>.   If the  aperture size is  too  large,  then  the

extrusion amount becomes large, the nozzle pressu1:e becomes too large, the

20    rate at which the undrawn yams flow out becomes too high, and thus winding of the yarns tends to be difficult, so that such an aperture size is not preferable.

[0033] With the thus obtained polyvioyl chloride• based fiber of the present invention, it is possible additionally to provide style changeability without

25    impairing matte properties and touch, which axe characteristics of a conventional vinyl chloride•based fiber. The reason of why a polyvinyl

chloride•based fiber with these characteristics is obtained is not certain, but it

seems  that  gels  of  the  crosslinked  vinyl  chloride  resin  insoluble  during

melt-spinning emerge as projections on the fiber su1face, and intertwining of

30    yarns extremely is improved with a specific fiber cross section, and thu.':l style

changeability that has not been provided in conventional examples is present.

Examples

[0034)  Hereinafter,  specific  embodiments  of  the  present  invention  are

5    described in more detail by way of examples, but the present invention is not limited to these examples.

[0035] (1) Evaluation of spinnability

In  a  melt-spinning  process,  an  occurrence  state  of yam breaking

visually was observed, and evaluated according to the following four grades.

10    4: yam breaking occurred once or less/hour.

a:    yarn breaking occurred 2 to 3 times/hour.

2:    yarn breaking occurred 4 to 6 times/hour.

1:    yarn breaking occurred 7 to 15 times/hour. [0036) (2) Matte properties

15 A bundle of fibers after melt-spinning was observed, and evaluated according to the following four grades. When judging matte properties, a vinyl chloride-based fiber ADVANTAGE-R manufactured by KANEKA CORPORATION was taken as Rank 3 (lusterless).

4: significantly lusterless

20    3: lusterless

2: comparatively lustrous

1: lustrous [0037) (3) 'lbuch

A bundle of fibers after melt-spinning was touched for judgment, and

25    evaluated according to the following four grades. When judging touch, a vinyl chloride-based fiber ADVANTAGE-R manufactured by KANEKA CORPORATION was taken as Rank 4 (very soft and flexible).

4:    very soft and flexible

3: soft and flexible

30    2: comparatively hard

1: very hard

[0038) (4) style changeability

In the following manner,  a simple wig for evaluation was produced

and evaluated.   The obtained fibers are cut into length of 25 em, 2 g of the

5    cut fibers uniformly are spread in a width of 10 em in a straight line, and the fibers are sewed on cloth or the like using a sewing machine. Ten such groups of fibers were produced and arranged spaced apart from each other by 1 em in the vertical direction, and thus a wig for evaluation was obtained. This wig was wound around a metal pipe having a diameter of 32 mm, and

10    the wig was curled by being set for one hour in a drier in which the temperature had been adjusted to 95°C. Easiness in setting style was evaluated according to the following four grades, when changing the style (A) shown in FIG. 4 into the style (B) shown in FIG. 5 by brushing the wig.

4: brushing twice or less is sufficient for changing the style (A) into

15    the style (B), that is, the style can be set very easily.

3: brushing 3 to 5 times is sufficient for changing the style (A) into the style (B), that is, the style can be set easily.

2: brushing 6 times or more is necessary for changing the style (A) into the style (B).

20 1: however many times brushing is performed, the style (A) cannot be changed into the style Ql).

[0039) (5) Major diameter and minor diameter on a cross• sectional shape

The diameters of a crosswsectional shape were measured by cutting cross sections with a cutter or the like, observing ten cross sections with a
25    SEM at a magnification of 300 times, measuring the major diameter B and the minor diameter A on each cross section, and calculating average values of the ten cross sections.
[00•10] (6) Length of projections on a fiber sw-face

A fiber surface was observed with a SEM at a magnification of 1000

30    times,  ten  projections  were  selected,   the  longitudinal  lengths  of  the

projections were measured, and an average value of the ten projections was

calculated.

[0041] (Examples 1 to 9 and Comparative Examples 1 to 5)

Vinyl chloride resins, partially crosslinked vinyl chloride resins, stabilizers, lubricants, and additives in predetermined ratios llilted in Table 1 below were agitated and mixed using a Henschel mixer, and thus compounds were produced. It should be noted that PES•250 manufactured by Nippon Unicar Company Limited was used as an EVA resin, and that PA-20 manufactured by KANEKA CORPORATION was used as a processing aid.

10    In addition to the substances listed in Table 1, 0.5 parts by weight of EW•100 manufactured by Riken Vitamin Co., Ltd. and 0.5 parts by weight ofHW400P manufactured by Mitsui Chemicals, Inc. were added as lubricants in all of the examples and the comparative examples. A nozzle was attached to an

extruder with a diameter of 30 mm,  the nozzle having 120 opeuings with a

15    cross section af 0.1 mm2 . The compounds were melt extruded under conditions providing good spinnability at a cylinder temperature of 140 to 190°C and a nozzle temperature of 180 ± 15°C. The extruded filaments were
subjected to thermal treatment for approximately 0.5 ro 1.5 seconds within a

heat•spinning  tube  (200  to  3000C  atmosphere,  conditions  providing  good

20    spinnability) provided directly under the nozzle. The produced undrawn yarns were sent by a take•in roll so as to be subjected to a drawing process. Immediately before the take•in roll, an oil was added to the undrawn yarns such that the weight fraction of an oil net content was 0.2 wt% with respect to the weight of the final product. Next, the undrawn yarns were drawn to

25    three times between the take•in roll and a drawing roll through a hot air circulation chamber at l10°C. Furthermore, the yarns were stretched between two pairs of circular cone rolls arranged in the chamber in which the temperature had been adjusted to ll0°C. Relaxation treatment at 35% then

was performed,  and multifilaments  at a single yarn fineness  of 70 decitex

30    were  wound.    The  processability  (spinnability)  at  that  time  and  the
 
properties    of   the   obtained   multifilaments   were   evaluated   by   the

above-described methods, and the results are shown in Table 1.
 

19

[0042]

                                                                            Table 1                                                                , -                               
                                                    Ex.!    EL2    Ex.3        Ex.4    EL5            Ex. 6            Ex.7        EL8            Ex.9        Com.        Com.        Com.        Com.            Com.   
                                                                                                                            Ex. I        Ex.2        Ex. 3        Ex. 4                Ex. 5       
                                                                                                                                                                                                   
                !            PVC                87    87    87        87    87            87                87        100            87        87            87            87        B7            87       
                            OPVC                13    13    13        13    13            13                13                    13        !3            13            13        !3            13       
                J  PVCre.sm        partially    (!)        3        0.5        20    3                3                    3        3            3                                        25            3       
                            crosslinktod        (2)            3                                                                                                                                                   
                            PVC    (3)                                                                                                        3                                                       
    ~,.    stabilizer                    (4)                                                                                                                    3                                           
                stabilizer (I)                I    I    I            I                        I            I        I                I        I        I    I        I    0.5        I    0.5       
                    stab.ilizar(2)                0.5    0.5    0.5        0.5                    0.5                0.5        0.5            0.5        0.5            0.5        0.5                           
        a.                stabilizer(3)                                        1.5                                                                                                                           
    •;;;                stabilizer(4)                                        0.8    t                    t        t                                                                                   
    "    lul11icant        lubricant(l)                I    I    I            I                I        I        I                                                                               
                    lubricant(2)                1.4    1.4    1.4        1.4            I        1.4        I    1.4    I    1.4        I    1.4    I    1.4        I    1.4    I    1.4    I    1.4            1.4       
                            lubricant (3)                                        0.6                                                                                                               
                                                                                                                                                                                               
                                                                                                                    - t                                                                                   
                            lubricant (4)                                        ~;    t                    t                t            t            t            t        I                           
                adchtive    EVA resin                13    13    13        !3            13            !3        2        13        !3            13            13        !3            13       
                        l    processing aid                I    I    I            I    J_ i   I    l    l    l    0.2    l        I    l    l    l    l    l    1    _j.    1                       
        spmnability!matte prope:rtieos                                                                                                                                                                       
        quality    touch                                        -:I                                                                                                                                           
                    stvlinttnronertit'!S                4    4    3            ~~~~~1=1~1~1~1~1~~~                       
        oro~    j B'Aratio                        I    1.so    1.48    1.52                                   
) ::>eciJ.on    / crnss•sectionalshape            1 su•    Six•    ~1~1~1~1~1~1=1~1~1~1~1-       
                                                    Je.¥00    leaved           
        surface proJI:tction average lJ.ln            I    10    21    s        12    n            10                12        s            10        o.s        as    r    a    l    10    _1        n   
                                                                                                                                                                       

PVC: degree of polymerization 1000 chlorinated vinyl chloride (CPVC): degree of polymerization BOO, degree of chlormation 64% partially cros.glioked vinyl chloride: (1) gel fraction 22%, degree of polymerization 1000, (2) gel fraction 43%, degree of polymerization 1000
(3) gel fraction 15%, degree of polymerization 760, (4) gel fraction 48%, degree of polymerization 1300 stabilizer: (J) butyltin mercapto stabilizer, (2) butyltin maleate stabilizer, (3) bydrutalcite, (4) dibenzoybnethane

lub1icant: (l) calcium stearate, (2) magnesium stearate, (3) calcium 12-hydruxystearate, (4) magnesium J2•hydruxystearate

[0043] In Comparative Example 1, a fiber was produced as in Example 1, except that another type of partially crosslinked vinyl chloride was used. It is shown that if the gel fraction of the crosslinked vinyl chloride is lower than

18% in this manner, then surface projections are small, and thus the style

changeability sigoificantly is lowered, and the matte properties also are lowered.

In Comparative Example 2, a fiber was produced as in Example 1, except that another type of partially crosslinked vinyl chloride was used. It is shown that if the gel fraction of the crosslinked vinyl chloride is higher

10    than 45%, then suri'ace projections are larger, and thus the spinuahility and the touch are degraded, so that this fiber is not preferable.

In Comparative Example 3, a fiber was produced as in Example  1,

except that no partially crosslinked vinyl chloride was added. In this case, the matte properties and the style changeability sigoificantly are poor as in

15    Comparative Example 1.

In Comparative Example 4, a fiber was produced as in Example 1, except that 25 parts of partially crosslinked vinyl chloride was added. In this case, the spinnahility and the touch are poor, so that this fiber is not preferable.

20 In Comparative Example 5, a fiber was produced as in Example 1, except that the cross•sectional shape is circular. In this case, the matte properties and the style changeability tend to be poor.

[0044] The results in Table 1 show that a polyvinyl chloride•based fiber, comprising a vinyl chloride resin composition that comprises (a) 100 parts by

25    weight of vinyl chloride resin, and (b) 0.2 to 20 parts by weight of crosslinked vinyl chloride resin in which the weight fraction of constituents that are insoluble in tetrahydrofuran is 18 to 45% and the viscosity average degree of polymerization of constituents that are soluble in tetrabydrofuran is 500 to

1800, wherein a cross-sectional shape of the fiber comprises a combination of

30    two  or  more  of  circles,  ellipses,   and  parabolas,  has  excellent  style
 
changeability    while   keeping   matte   properties,   touch,    and   other

chaxacteristics of a conventional vinyl chloride• based fiber.

Industrial Applicability

[0045] When the fiber of the present invention having a specific cross• sectional shape is used as artificial hair, it is possible to provide style changeability without impairing matte properties and touch of the vinyl chloride•based fiber. Furthermore, the fiber of the present invention can be produced stably by melt•spinning, and thus an industrial advantage also is
10    provided.
 
CLAIMS

1.    A polyvinyl  chloride-based  fiber,  comprising  a  vinyl  chloride  resin

composition that comprises:

5    (a) 100 parts by weight of vinyl chloride resin; and

(b)    0.2 to 20 parts by weight of crosslinked vinyl chloride resin in which a weight fraction of constituents that are insoluble in tetrahydrofuran is 18 to 45% and a viscosity average degree of polymerization of constituents that are soluble in tetrahydrofuran is 500 to 1800,

10    wherein a cross-sectional shape of the fiber comprises a combination

of at least two circles.

2.    The polyvinyl chloride-based fiber acrording to claim 1, wherein the

cross•sectional shape of the fiber comprises a combination of at least three

15    circles.

3.    The polyvinyl chloride-based fiber according to claim 1, wherein the

cross-sectional shape  of the fiber comprises  a combination of at least four

circles.

20

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

25    5. The polyvinyl chloride-based fiber according to claim 1, wherein the surface of the fiber further has protrusions, and an average longitudinal length of the protrusions is 1 ~ to 30 ~m.

6.    The polyvinyl chloride-based fiber according to any one of claims 1 to

30    5, wherein the cross-sectional shape of the tiber comprises the combination
 
and further an ellipse or a parabola.

7.    The polyvinyl chl01ide•based fiber according to any one of claims 1 to

6, wherein the cross•sectional shape of the fiber is the shape of a star having

5    five or six projecting portions.

8.    The polyvinyl chloride• based fiber according to any one of claims 1 to

7, wherein an area of the projecting portion of the cross section of the fiber is

1120 or more with respect to an area of the largest inscribed circle of the cross

10    section, the area of the projecting portion being an area of a portion enclosed by a straight line connecting two local minimum points on both sides of the projecting portion, and a curved line forming the projecting portion.

9.    The polyvinyl chloride-based fiber according to claim 1, wherein the

15    vinyl  chloride  resin  (a)  is  a  homopolymer  resin  that  is  vinyl  chloride

homopolymer, or a copolymer resin containing vinyl chloride.

10.    The polyvinyl chloride•based fiber according to claim 9, wherein the

copolymer resin is at least one  type  of copolymer selected from  the  group

20    consisting of a vinyl chloride I vinyl acetate copolymer resin, a vinyl chloride I vinyl propionate copolymer resin, a vinyl chloride I butyl acrylate copolymer resin, a vinyl chloride /2•ethylhexyl acrylate copolymer resin, a vinyl chloride I ethylene copolymer resin, a vinyl chloride I propylene copolymer resin, and a vinyl chloride I acrylonitrile copolymer resin.

25

11.    The polyvinyl chloride-based fiber  according to  claim  1, wherein  a

chlorinated vinyl chloride resin is mixed in a ratio of 0 to 40 wt% with respect

to 100 to GO wt% of the vinyl chloride resin.

30    12.    The polyvinyl chloride-based fiber according to claim 1, wherein the
 
vinyl chloride resin is  a chlorinated vinyl chloride resin having a chlorine

content of 58 to 72%.

13. The polyvinyl chloride-based fiber accorlling to clrum 1, wherein at least one type of thermal stabilizer selected from the group consisting of a tin•based thermal stabilizer, a Ca•Zn•based thermal stabilizer, a hydrotalcite•based thermal stabilizer, an epoxy•based thermal stabilizer, and a ~-diketone•based thermal stabilizer is added to the vinyl chloride resin

composition.

10

14. The polyvinyl chloride-based fiber according to clrum 13, wherein the thermal stabilizer is added in an amount of 0.2 to 5 parts by weight to the

vinyl chloride resin composition.

15    15. The polyvinyl chloride-based fiber according to claim 1, wherein at least one type of 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 vinyl chloride resin composition.

20

16.    The polyvinyl chloride-based fiber according to claim 15, wherein the

lubricant is added in an amount of 0.2  to 5.0 parts by weight  to the vinyl

chlmide resin composition.

25    17. The polyvinyl chloride-based fiber according to claim I, wherein an ethylene I vinyl acetate (EVA) resin is added to the vinyl chloride resin composition.


18.    The polyvinyl chloride-based fiber  according to claim  I, wherein an

30    acrylic resin is added to the vinyl chloride resin composition.


19.    The polyvinyl chloride-based fiber according to claim 1, wherein a viscosity average degree of polymerization of the vinyl chloride resin is at least 450 and at most 1800.

20.    The polyvinyl chloride-based fiher according to any one of claims 1 to 19, wherein the polyvinyl chloride-based fiber is a fiber for artificial hair.
 



ABSTRACT

A polyvinyl chloride-based fiber of the present invention is a fiber

formed with a vinyl chloride resin composition that comprises (a) 100 parts by

5    weight of vinyl chloride resin, and (b) 0.2 to 20 parts by weight of crosslinked vinyl chloride resin in which a weight fraction of constituents that are insoluble in tetrahydrofuran is 18 to 45% and a viscosity average degree of polymerization of constituents that are soluble in tetrahydrofuran is 500 to 1800, in which a cross-sectional shape of the fiber comprises a combination of

10    at least two of circles, ellipses, and parabolas. When this fiber is used as artificial hair, it is possible to provide style changeability without impairing matte properties and touch of the vinyl chloride-based fiber. Furthermore, the fiber of the present invention can be produced stably by melt-spinning, and thus an industrial advantage also is provided.


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