JP6411923B2 - Atypical synthetic fiber multifilament - Google Patents

Description

  The present invention relates to an atypical synthetic fiber multifilament, and more particularly to a lightweight and bulky atypical synthetic fiber multifilament.

  Synthetic fibers have various excellent properties including mechanical properties and are used in various industrial applications and fields. More recently, not only is the strength simply required, but there is a demand for a high-strength fiber product while maintaining its bulkiness when it is low in density and excellent in strength, that is, finally made into a fiber product. There is a field.

  For example, in the field of industrial materials such as ropes and nets, if the fibers are simply strengthened, the final product having the same strength is composed of thin yarns. In that case, however, stress concentrates on the held portion. For example, when a thin and high-strength rope is used, there is a problem in that it tends to bite into a hand holding the rope, causing pain and injury more easily than using a thick rope.

  Therefore, a technique is known in which fibers are hollowed out to obtain a low-density fiber product. For example, the spinneret is hollow and a hollow fiber is obtained. However, the hollow fiber obtained by such a method is easily crushed in the hollow part in an industrial fiber application where a strong force is applied, and has not been able to exhibit sufficient bulkiness. In addition, when adopting a spinning method that changes to a complicated die shape, a high bonding technology (die design) of the polymer that is melted and discharged from the die discharge hole is required, and there is a basic problem that the fiber is easily broken. It was.

  In addition, for example, fibers having various cross-sectional shapes are known in the carpet field (for example, Patent Document 1 and Patent Document 2). There is a problem in that the strength is greatly reduced, and fluff is generated in the intermediate process such as the stretching process, and deformation of the cross-sectional shape such as crimping is large. There has been a long-awaited demand for lightweight, high-bulk multifilament fibers suitable for industrial materials.

JP 2002-88564 A JP 2005-126841 A

  An object of the present invention is to solve the above-described problems of the prior art and to provide a high-strength atypical synthetic fiber multifilament that is lightweight and bulky.

The atypical synthetic fiber multifilament of the present invention is an aggregate of atypical synthetic fibers comprising a core part and a fin part, wherein the specific gravity of the atypical synthetic fiber is 1.3 or less and satisfies the following requirements: And
a) The fin portion protrudes from the outer surface of the core portion so as to intersect the center point of the core portion, and extends along the length direction of the core portion.
b) The porosity of the following formula (1) in the cross section orthogonal to the fiber axis of the atypical fiber is 5 to 20%, and the core cross-sectional area ratio of the following formula (2) is 30 to 45%.
Porosity (%) = {(B−A) / B} × 100 (1)
Core cross-sectional area ratio (%) = (C / A) × 100 (2)
(Here, A: the area of the polymer part in the cross section orthogonal to the fiber axis, B: the area of the cross section orthogonal to the fiber axis, the area of the fin portion extending in the fiber axis length direction and connected in a straight line, C: The area of the core part connecting the bases of the fin part extending in the fiber axis length direction with a straight line in a cross section perpendicular to the fiber axis)
c) The strength of the fiber is 5 cN / dtex or more.

Furthermore, it is preferable that the synthetic fiber is a polyolefin fiber, the number of fin portions is 4 or more, and the aggregate is a multifilament composed of 12 or more deformed fibers.
And this invention includes the textiles which consist of the above-mentioned atypical synthetic fiber multifilament of this invention.

  According to the present invention, an atypical synthetic fiber multifilament having high strength while being lightweight and bulky is provided.

It is a schematic diagram of one specific example of the spinneret used when manufacturing the single yarn which comprises the atypical synthetic fiber multifilament of this invention. It is a schematic diagram of the cross section orthogonal to the fiber axis of the single yarn which comprises the atypical synthetic fiber multifilament of this invention, Comprising: The white background part in a chain line is a "gap area." It is a schematic diagram of the cross section orthogonal to the fiber axis of the single yarn which comprises the atypical synthetic fiber multifilament of this invention, Comprising: The part in a chain line is a "cross-sectional area of a core part."

Hereinafter, embodiments of the present invention will be described in detail.
The atypical synthetic fiber multifilament of the present invention is an aggregate of atypical synthetic fibers comprising a core portion and a fin portion, and the specific gravity of the atypical synthetic fiber is required to be 1.3 or less. Thus, it is a multifilament excellent in lightweight property and bulkiness by using the atypical fiber which consists of a synthetic fiber with low specific gravity.

  The synthetic fiber preferably used in the present invention is preferably a polyolefin fiber, and more preferably a polypropylene fiber. Furthermore, as a fiber of this invention, it is preferable that a melt flow index (MFR) is the range of 20-22. Here, MFR is a value obtained by measurement using a die according to JIS K7210 under a temperature of 230 ° C. and a loading load of 2.160 kg.

Further, the specific gravity of the atypical synthetic fiber is required to be 1.3 or less, more preferably 0.8 to 1.2, and particularly preferably 0.9 to 0.98. Moreover, as melting | fusing point, it is preferable that it is the range of 160-180 degreeC, and it is especially preferable that it is 164-165 degreeC.
Furthermore, it is also a preferable aspect that a UV absorbent, a flame retardant, and an original master chip are added to the polymer forming the synthetic fiber as necessary to provide functionality.

  The atypical synthetic fiber multifilament of the present invention is composed of the above-described synthetic fiber, and the cross-sectional shape orthogonal to the fiber axis of each constituent single yarn constituting the multifilament is a deformed fiber having a core portion and a fin portion. is necessary.

The present invention further satisfies the following requirements.
a) The fin portion protrudes from the outer surface of the core portion so as to intersect the center point of the core portion, and extends along the length direction of the core portion.
b) The porosity of the following formula (1) in the cross section orthogonal to the fiber axis of the atypical fiber is 5 to 20%, and the core cross-sectional area ratio of the following formula (2) is 30 to 45%.
Porosity (%) = {(B−A) / B} × 100 (1)
Core cross-sectional area ratio (%) = (C / A) × 100 (2)
(Here, A: the area of the polymer part in the cross section orthogonal to the fiber axis, B: the area of the cross section orthogonal to the fiber axis, the area of the fin portion extending in the fiber axis length direction and connected in a straight line, C: The area of the core part connecting the bases of the fin part extending in the fiber axis length direction with a straight line in a cross section perpendicular to the fiber axis)
c) The strength of the fiber is 5 cN / dtex or more.

  The atypical synthetic fiber multifilament fiber of the present invention is a multifilament suitable for industrial materials by realizing the high strength of the fiber while taking the atypical shape as described above.

  Further, the atypical fiber constituting the atypical synthetic fiber multifilament of the present invention includes a plurality of fins that protrude radially from the core portion outer surface with respect to the core portion center point and extend along the length direction of the core portion. Part is preferably present. The number of fins is preferably 4 or more, particularly preferably 4 fin portions. When the number of fin portions is too small, the porosity is too low, and when the number of fin portions is too large, the core cross-sectional ratio tends to be too large. And by using each discharge slit of the spinneret as shown in FIG. 1, it is possible to obtain a higher bonding property between the respective discharge polymers, and to stably obtain the target single yarn cross-sectional shape.

  In the present invention, a single yarn in a multifilament state is formed by having a shape that has a fin portion that protrudes radially from the core portion outer surface to the core portion center point and extends along the length direction of the core portion. A high volume exclusion effect due to the interference between the two can be obtained, and a high void formation rate can be obtained.

  The number of single yarns constituting the multifilament of the present invention is preferably 12 or more multifilaments, more preferably 40 to 500, especially 60 to 250 single yarns. preferable. Such a multifilament of the present invention has a more effective volume exclusion effect due to the attachment of the fins, and can obtain a sufficient bulkiness.

In the atypical synthetic fiber multifilament of the present invention, in the cross section of each constituent single yarn, the porosity of the single yarn of the following formula (1) existing in the region surrounded by the tips of the plurality of fin portions is 5 to 20%. It is necessary to be. Furthermore, the porosity is preferably in the range of 5 to 12%.
Porosity (%) = {(B−A) / B} × 100 (1)
(Here, A: the area of the polymer part in the cross section orthogonal to the fiber axis, B: the area of the cross section orthogonal to the fiber axis, the area of the fin portion extending in the fiber axis length direction and connected in a straight line, And)

  Thus, by suppressing the value of the porosity of each single yarn to a low value, it has become possible to obtain high-strength physical properties while achieving both light weight and bulkiness. Here, the porosity is a void other than the area (A) of the polymer constituting the fiber, present in the enclosed region (B) connecting the tips of the plurality of fin portions in the fiber cross section orthogonal to the fiber axis. Is the proportion occupied. In addition, the area of this area | region can be easily obtained from an electron micrograph, and the value calculated from the fineness (dtex) and the density of a polymer can be used for the area made into the cross section of the polymer which comprises a fiber.

Furthermore, the atypical synthetic fiber multifilament of the present invention simultaneously has a core cross-sectional area ratio of a single yarn of the following formula (2) existing in a region surrounded by the roots of a plurality of fin portions in the cross section of each constituent single yarn. It is necessary to be in the range of 30 to 45%. Furthermore, the core cross-sectional area ratio is preferably in the range of 33 to 40%.
Core cross-sectional area ratio (%) = (C / A) × 100 (2)
(Here, A: the area of the polymer part in the cross section perpendicular to the fiber axis, C: the area of the core part in the cross section perpendicular to the fiber axis, and connecting the base of the fin part extending in the fiber axis length direction with a straight line) )

  Thus, by setting the value of the core cross-sectional area ratio of each single yarn high, the multifilament of the present invention achieves both high-strength physical properties and bulkiness in a higher dimension by combining with the above void ratio. It became possible to do. In particular, the porosity is preferably in the range of 5 to 12%, and the core cross-sectional area ratio is preferably in the range of 33 to 40%. Here, the core cross-sectional area is the area occupied by the polymer constituting the fiber (C) surrounded by connecting the roots in contact with the core portion of the plurality of fin portions in the fiber cross section perpendicular to the fiber axis ( A ratio to A). The area of the C region of the core part can be easily obtained from an electron micrograph.

The strength of the high strength atypical multifilament of the present invention needs to be 5 cN / dtex or more. Further, it is preferably in the range of 5.5 to 8 cN / dtex. Thus, it is extremely difficult to achieve both high strength and high hollowness. In the present invention, the high strength hollow multifilament manufacturing method described later was obtained for the first time.
Furthermore, the total fineness of the multifilament is preferably 50 to 1700 dtex, more preferably 80 to 1600 dtex. The fineness of the single yarn constituting the multifilament is preferably in the range of 0.5 to 20 dtex, and particularly preferably in the range of 1 to 10 dtex.

  Such an atypical synthetic fiber multifilament of the present invention can be obtained by a known melt spinning and stretching method using a die having a discharge shape schematically shown in FIG. 1 and a heater under the die. At this time, in addition to the die shape, the void ratio and the core cross-sectional area ratio can be adjusted by changing the stretching load factor.

  Although the atypical synthetic fiber multifilament of the present invention thus obtained has a low specific gravity and a high strength, many voids can be formed between a plurality of single fibers in the fiber cross section. As a result, it is possible to obtain a multifilament in which the apparent specific gravity of the fiber is further lowered than the specific gravity of the fiber. For example, when a high-strength atypical multifilament of the present invention is used to form a rope or net, it is possible to obtain an easy-to-handle product having an appropriate bulk and thickness. When high-strength fibers are used, there is a problem that the rope or net becomes too thin and the visibility is lowered, or that a cut is caused in a portion in contact with a person. These problems can be effectively solved by making the atypical synthetic fiber multifilament of the present invention bulky.

Moreover, the atypical synthetic fiber multifilament of the present invention is also effectively applied to a nori culture net and the like. The surface area of the fiber increases and its effectiveness is further improved. Furthermore, since the effect of improving the surface area contributes to the improvement of adhesion, it is also effective as a reinforcing fiber for various resins.
The modified synthetic fiber multifilament of the present invention can be optimally used in a wide range of fields such as ropes for industrial materials, civil engineering work sheets, nets, fishing nets and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, each item in an Example was calculated | required with the following method.

(1) Melt flow index (MFR)
In accordance with JIS K7210, measurement using a die was performed under conditions of a temperature of 230 ° C. and a loading load of 2.160 kg, and a melt flow index (MFR) value was obtained.

(2) Porosity (%), core area (%)
The porosity is determined by cutting a section of multifilament that has been spin-cut and taking a cross-sectional photograph (560 to 35000 times) perpendicular to the fiber axis of a single yarn by SEM (scanning electron micrograph). The area of the polymer part in the cross section perpendicular to the fiber axis of each single yarn was defined as area A. Further, an area of a region in which the vertices of the fin portions extending in the fiber axis length direction in a cross section perpendicular to the fiber axis of the filament yarn are connected by a straight line is defined as an area B.
Then, the area of the core portion where the root of the fin portion extending in the fiber axis length direction of the cross section perpendicular to the fiber axis of the filament yarn is connected in a straight line is defined as area C.
Using these areas A to C, the single yarn void ratio and the core part cross-sectional area ratio were determined by the following equations. The measurement was performed at five fiber cross sections, and the average value was used.
Porosity (%) = {(B−A) / B} × 100 (1)
Core cross-sectional area ratio (%) = (C / A) × 100 (2)
A: Area B of the polymer part in a cross section perpendicular to the fiber axis; Area C of the cross section perpendicular to the fiber axis, where the vertices of the fins extending in the fiber axis length direction are connected by straight lines; orthogonal to the fiber axis Area of the section where the base of the fin part extending in the fiber axis length direction is connected by a straight line

[Example 1]
Polypropylene resin (MFR = 22, specific gravity 0.9) was melted at 235 ° C. and discharged from a spinneret having 72 discharge holes shown in FIG. The discharged yarn is heated by a heated spinning cylinder having a length of 45 mm and a temperature of 235 ° C. under a base, and then cooled at 25 ° C. and a wind speed of 0.1 Nm / min, and oil is applied by an oiling roller to 500 m / min. Winded up at speed. The obtained undrawn yarn was drawn at a temperature of 70 ° C. to 100 ° C. and drawn with a draw rate of 85%, and then heat-set at a temperature of 160 ° C. Fiber). The number of fins was four and the direction of the fins with respect to the hollow center point of the core portion was crossed. The obtained fiber was excellent in lightweight feeling with a porosity of 11%. The core part cross-sectional area of the fiber axis cross section was 35%, and there was little breakage of single yarn on the drawing roller, and it was a highly stable, high-strength irregular multifilament.

[Example 2]
Except having changed the draw load factor from 85% to 80%, it carried out similarly to Example 1 and obtained the atypical synthetic fiber. The obtained fiber had 99 dtex, strength 6.3 cN / dtex, elongation 26%, and porosity 7%. The core area cross-sectional area of the fiber axis cross section was 39%, and there was little breakage of single yarn on the drawing roller, and it was a highly stable, high-strength irregular multifilament.

[Comparative Example 1]
Except having changed the draw load factor from 85% to 90%, it carried out similarly to Example 1 and obtained the atypical synthetic fiber. The obtained fiber had physical properties of 85 dtex, strength 7.6 cN / dtex, elongation 20.0%, and porosity was 15%. However, the core area cross-sectional area of the fiber axis cross section was 29%, and there were many single yarn breaks on the drawing roller, which hindered stable production.

A: Polymer part B having a cross section perpendicular to the fiber axis; region C in which the vertices of the fin part are connected by a straight line (chain line); core part in which the root of the fin part is connected by a straight line (chain line)

Claims (5)

An atypical synthetic fiber multifilament characterized in that it is an aggregate of atypical synthetic fibers comprising a core portion and a fin portion, wherein the specific gravity of the atypical synthetic fiber is 1.3 or less and satisfies the following requirements.
a) The fin portion protrudes from the outer surface of the core portion so as to intersect the center point of the core portion, and extends along the length direction of the core portion.
b) The porosity of the following formula (1) in the cross section orthogonal to the fiber axis of the atypical fiber is 5 to 20%, and the core cross-sectional area ratio of the following formula (2) is 30 to 45%.
Porosity (%) = {(B−A) / B} × 100 (1)
Core cross-sectional area ratio (%) = (C / A) × 100 (2)
(Here, A: the area of the polymer part in the cross section orthogonal to the fiber axis, B: the area of the cross section orthogonal to the fiber axis, the area of the fin portion extending in the fiber axis length direction and connected in a straight line, C: The area of the core part connecting the bases of the fin part extending in the fiber axis length direction with a straight line in a cross section perpendicular to the fiber axis)
c) The strength of the fiber is 5 cN / dtex or more.   The atypical synthetic fiber multifilament according to claim 1, wherein the synthetic fiber is a polyolefin fiber.   The atypical synthetic fiber multifilament according to claim 1 or 2, wherein the number of fin portions is 4 or more.   The atypical synthetic fiber multifilament according to any one of claims 1 to 3, wherein the aggregate is a multifilament composed of 12 or more irregular fibers.   A fiber product comprising the atypical synthetic fiber multifilament according to any one of claims 1 to 4.