JPH11256421A - High-strength and high-hollowness thermoplastic synthetic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high-strength and high-hollowness thermoplastic synthetic fiber that has excellent bulkiness and high strength and high elasticity. SOLUTION: This is a hollow and non-crimpy fiber made of a thermoplastic polymer and has the following properties (1)-(6): (1) 10<=P<=50; (2) D>=600; (3) D>=5; (4) T>=6; (5) Y>=80; and (6) To>=100 (P is the percentage of hollowness of the filament in %; D is the total fiber fineness in dtex; (d) is the filament fineness in dtex; T is the strength at break in cN/dtex; To is the fiber toughness in cN.%/detex).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength high-hollow thermoplastic synthetic fiber, and more particularly to a high-strength high-hollow thermoplastic synthetic fiber suitable for industrial materials.

[0002]

2. Description of the Related Art Thermoplastic synthetic fibers are widely used in the world because of their excellent performance such as high strength in one axis direction, quality stability, and low price. Among its uses, it is widely and effectively used as a material for maintaining strength by utilizing its high strength properties for industrial materials.

On the other hand, it absorbs a load from the side,
There are many fields where bulkiness is required for fibrous materials in order to improve heat retention and cold retention, or to impart flexibility and swelling to fiber products, and it is usually necessary to express bulkiness And crimping.

However, the crimped fiber loses linearity in the direction of the fiber axis, so that its strength and elastic modulus are inferior, and it is disadvantageous as a high-strength fiber.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic synthetic fiber which compensates for the above-mentioned drawbacks, is excellent in bulkiness, and has high strength and high elastic modulus.

[0006]

Means for Solving the Problems To solve the above-mentioned problems, the high-strength high-hollow thermoplastic synthetic fiber of the present invention mainly has the following constitution. That is, it is a high-strength high-hollow thermoplastic synthetic fiber which is a hollow fiber made of a thermoplastic polymer and has the characteristics of (1) to (6) and is non-crimpable.

(1) 10 ≦ P ≦ 50 (2) D ≧ 600 (3) d ≧ 5 (4) T ≧ 6 (5) Y ≧ 80 (6) To ≧ 100 (where P is the hollow ratio (% ), D is the total fineness (dte
x) and d are single yarn fineness (dtex), T is breaking strength (cN
/ Dtex), Y is Young's modulus (cN / dtex), To
Is toughness (cN ·% / dtex)

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The high-strength high-hollow thermoplastic synthetic fiber of the present invention is made of a thermoplastic polymer. As the thermoplastic polymer, polyethylene, polypropylene, polyvinyl alcohol, ethylene vinyl acetate copolymer, polyolefin polymer such as polystyrene, or polyhexamethylene adipamide, polytetramethylene adipamide,
Polyamide polymers such as polycapramide, and polyester polymers such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, aliphatic polyester, and liquid crystal polyester.

Among them, polyester polymers and polyamide polymers are preferably employed in order to obtain high-strength fibers, and polyester polymers are more preferable in view of the retention of weather strength and dimensional stability. At this time, the intrinsic viscosity of the polyester-based polymer is preferably 0.8 or more, more preferably 0.9 or more, from the viewpoint of increasing the strength.

The thermoplastic polymer may contain a small amount of additives. For example, known flame retardants, antistatic agents,
Matting agents, crystal nucleating agents, viscosity reducing agents, hydrolysis inhibitors, weathering agents, deterioration inhibitors, pigments and the like. Further, it is preferable to contain a low molecular weight compound containing an aromatic component which has high strength and high toughness.

The high-strength high-hollow thermoplastic synthetic fiber of the present invention has a hollow ratio P (%) of 10% or more and 50% or less. The hollow ratio is a ratio of the cross-sectional area of the hollow portion to the total cross-sectional area of the fiber including the hollow portion. If the hollow ratio is less than 10%, the desired bulkiness of the present invention cannot be obtained. On the other hand, if the hollow ratio exceeds 50%, it is difficult to maintain the hollow shape after the product is formed. The hollow ratio is preferably 20% or more and 40% or less from the viewpoint of obtaining better bulkiness and hollow shape maintenance.

The cross-sectional shape of the high-strength high-hollow thermoplastic synthetic fiber of the present invention is not particularly limited as long as the hollow ratio is in the above range, and may be a circle, Y, T, flat, cross, or the like.
The number of hollow portions may be one or two or more. From the viewpoint of high strength, the degree of irregularity expressed by the ratio of the inscribed circle to the circumscribed circle is preferably 2 or less, and the number of hollow portions is preferably one.

The high-strength high-hollow thermoplastic synthetic fiber of the present invention has a total fineness D (dtex) of 600 dtex or more. 6
If less than 00 dtex, even if the strength of each single fiber is high, the strength as a whole fiber cannot be increased,
It becomes inferior as a strong holding material. From the viewpoint of increasing the strength as a whole fiber, the total fineness is 10
00 dtex or more, preferably 1500 dt
It is more preferably ex or more. On the other hand, from the viewpoint of production of a synthetic fiber, it is preferably 5000 dtex or less.

The high-strength high-hollow thermoplastic synthetic fiber of the present invention has a single fiber fineness d (dtex) of 5 dtex or more. 5
If it is less than dtex, the hollow form after the product cannot be maintained, and the bulky effect cannot be exhibited. From the viewpoint of further exhibiting the effect of bulkiness, the single yarn fineness is preferably 10 dtex or more,
More preferably, it is 20 dtex or more. However,
When used for fabrics and net products that require moderate suppleness as a product, the single fiber fineness is, for example, 10 dt.
ex or less is preferable. The single fiber fineness is the total fineness D (d
tex) may be divided by the number of filaments of the fibers constituting the tex), and the thick yarn and the fine yarn may be mixed. From the viewpoint of high strength, the fineness of each single fiber is preferably substantially the same.

The breaking strength T (cN / dtex) of the high-strength high-hollow thermoplastic synthetic fiber of the present invention is 6 cN / dtex or more. When it is less than 6 cN / dtex, the high-strength fiber aimed at by the present invention cannot be obtained. From the viewpoint of further increasing the strength, the strength is preferably 7 cN / dtex or more, more preferably 8 cN / dtex or more. On the other hand, if the strength is too high, the molecular chains are aligned in one direction inside the fiber, so that the hollow shape as a product cannot be maintained and fibrillation is caused. It is preferred that

The high-strength high-hollow thermoplastic synthetic fiber of the present invention has a Young's modulus (cN / dtex) of 80 cN / dtex or more. Conventional bulky fibers are crimped and thus easily deformed under a low load, and the Young's modulus required for high-strength fibers is insufficient, which is unsuitable. 80cN /
If it is less than dtex, it becomes impossible to suppress deformation under a low load. Further, the Young's modulus is preferably 110 cN / dtex or more, more preferably 150 cN / dtex or more, from the viewpoint of suppressing deformation under a low load. On the other hand, if the Young's modulus is too high, the molecular chains are aligned in one direction inside the fiber, so that the hollow shape of the product cannot be maintained and fibrillation is caused. From this viewpoint, 250 cN / It is preferably dtex or less.

The toughness To (cN.% / Dtex) of the high-strength high-hollow thermoplastic synthetic fiber of the present invention is 100 or more. Toughness To is calculated by the following equation: To = T × E. Here, T is the aforementioned breaking strength (cN / d
tex), and E is the elongation at break (%). The toughness is a value indicating the energy absorbed by the fiber before the fiber breaks, and it is necessary that not only the breaking strength be high but also the breaking elongation be high. That is, the toughness is 100 cN ·% /
By being dtex or more, it becomes a practical high-strength fiber. From this viewpoint, the toughness is 150 cN ·% / dte
x or more is preferable, and 200 cN ·% / dtex or more is more preferable.

An example of the method for producing the high-strength high-hollow thermoplastic synthetic fiber of the present invention is shown below.

[0020] A polyethylene terephthalate chip having an intrinsic viscosity of 1.2 to 1.5 or a nylon 6 or nylon 66 chip having a relative viscosity of 2.8 or more is melted, filtered, and the melt is discharged from a die. 1 just below the base
After passing through a heated zone of 0 to 50 cm, the mixture is cooled and solidified to supply oil, and is drawn by a roller to form an undrawn yarn. The mouthpiece is preferably of a type in which gas is injected into the hollow portion, a type in which a melt discharged from one or a plurality of straight or curved slits is fused immediately after discharge, and the like.
The one having 50 or more hollow discharge portions is used. The take-off speed is 300-4000 m / min.

When producing high-strength hollow fibers, it is preferable to use a raw material having an intrinsic viscosity of 1.2 or more for polyester and a relative viscosity of sulfuric acid of 3.3 or more for nylon. Further, for filtering the molten resin, it is preferable to employ a filter having an absolute filtration diameter of 15 μm or less, and a plurality of slits are provided on the circumference of the base discharge hole, and a diameter of an inscribed circle of the slit is 1.2 mm. It is preferably not less than 2.5 mm and not more than 2.5 mm, and it is preferable to pass through a zone heated directly below the die by 10 to 50 cm to obtain the fiber of the present invention.

Then, the film is wound up once, or stretched and heat-treated without winding up. At this time, 0
Stretching of up to 5% and stretching in multiple stages are suitable for stably producing high-strength fibers without thread breakage, and heat treatment is performed at (melting point −50 ° C.) or higher and melting point or lower. In addition, it is suitable to perform a relaxation treatment of 3% or more and 20% or less after the heat treatment to achieve high toughness.

The high-strength high-hollow thermoplastic synthetic fiber of the present invention can be used for known industrial materials, such as heavy cloths, seat belts, airbags, slings, fishing nets, nets, heat- and cold-insulating sheets, curing sheets, Used for rubber reinforcement applications such as ropes, electric wire coverings, dry filters, wet filters, tire cords, hoses, belts, sewing threads, geogrids, etc. Among them, the bulky material can absorb the load from the side direction, and as a result, it can improve the safety and prevent the destruction of the textile product itself. Or, it is suitable for a sewing thread used for these.

[0024]

The present invention will be described below in detail with reference to examples. In addition, the physical property in an Example was measured as follows.

A. Breaking strength, breaking elongation, Young's modulus After leaving the sample in a temperature control room at 20 ° C. and 65% RT for 24 hours or more, using a Tensilon tensile tester manufactured by Orientec Co., Ltd., a test length of 25 cm and a take-up speed of 30 cm / S in minutes
A curve was obtained and the strength and elongation were calculated.

B. Intrinsic viscosity: A sample of 8 g in terms of the amount of polymer from which particles were removed by centrifugation was dissolved in 100 ml of orthochlorophenol, and the solution viscosity (η) was measured at 25 ° C. using an Ostwald viscometer. The intrinsic viscosity (IV) was calculated.

IV = 0.0242 · ηrp + 0.2634 where ηrp = (t × d) / (t ₀ × d ₀ ) t: Fall time of solution (second) t ₀ : Fall time of orthochlorophenol (second) d: density of solution (g / cc) d ₀ : density of orthochlorophenol (g / cc) Hollow defect ratio Using a 500D-96F PET fiber as a warp, a sample was driven as a weft to obtain a woven fabric having a warp density of about 25 yarns / inch. The cross section of the sample after weaving was observed, and the hollow defect ratio (%) was determined from the ratio of the single yarn in which the crack occurred.

[Examples 1 to 4 and Comparative Examples 1 and 2] Polyethylene terephthalate (PET) having an intrinsic viscosity of 1.29
Was prepared by a solid phase polymerization method, melted by an extruder type spinning machine, introduced into a spinning pack, filtered through a stainless steel nonwoven fabric filter having a filtration diameter of 15 μm, and spun from a 60-hole hollow die. The hollow mouthpiece has a hole depth of 0.5 mm,
Using a slit width of 0.15 mm and a circumference of 4 slits, the inner diameter of the circumference constituted by the 4 slits was changed as shown in Table 1, and the hollow ratio was changed. A heating cylinder of 20 cm was attached immediately below the base, and the inside of the cylinder was heated to an ambient temperature of 320 ° C. The ambient temperature in the cylinder is 10 cm from the base
The ambient temperature was measured at a position below and 1 cm away from the outermost yarn.

An annular chimney having a length of 40 cm was attached to the bottom of the heating cylinder, and the yarn was cooled by blowing cold air at a temperature of 25 ° C. and at a speed of 40 m / min. Next, after applying the oil agent, the yarn speed was controlled by a take-off roller of 500 m / min, and then the film was continuously drawn without being wound once.

The stretching is carried out by three pairs of Nelson-type rollers at a draw ratio of 3.5 times at the first stage and 1.6 times at a second stage.
After the step stretching, the film was wound with 8% relaxation between the following Nelson rollers. The take-up roller temperature was set to 100 ° C., and the first-stage stretching was performed between the take-up roller and the first stretch roller heated to 170 ° C.
The second stage of stretching was performed between the second stretching rollers heated to ° C. The next Nelson roller was used without heating. The discharge amount was adjusted so that the fineness of the wound yarn was 560 dtex, and the two yarns were combined to give a total fineness D of 1120 dtex. The single fiber fineness d is 9.3 dtex.

The evaluation results of the hollow fibers thus obtained are shown in Table 1.

Comparative Example 1 had a low hollow ratio and poor bulkiness, and Comparative Example 2 had a too high hollow ratio and a high hollow defect ratio, but the hollow ratio was within the range of the present invention. All of them were good ones having low physical properties and a low hollow defect ratio.

[0033]

[Table 1] [Example 5 and Comparative Examples 3 and 4] In Example 1, 560 dtex-60F fiber was used in Comparative Example 3 without doubling.
Was similarly evaluated.

Further, in Example 1, the discharge amount was changed to 280 dtex and 420 dtex, and four ply yarns and three ply yarns were used to make 1120 dtex and 1260 dtex, respectively.
The same evaluation was performed as Comparative Example 4 and Example 5 respectively. Table 2 shows the results.

[0035]

[Table 2]

[0036]

According to the present invention, there is provided a high-strength high-hollow thermoplastic synthetic fiber having excellent bulkiness and high strength and elastic modulus.

Claims (2)

[Claims] 1. A high-strength, high-hollow, thermoplastic synthetic fiber comprising a thermoplastic polymer, having the characteristics of (1) to (6) and being non-crimpable. . (1) 10 ≤ P ≤ 50 (2) D ≥ 600 (3) d ≥ 5 (4) T ≥ 6 (5) Y ≥ 80 (6) To ≥ 100 (where P is the hollow ratio (%), D Is the total fineness (dte
x) and d are single yarn fineness (dtex), T is breaking strength (cN
/ Dtex), Y is Young's modulus (cN / dtex), To
Is toughness (cN ·% / dtex) 2. The high-strength high-hollow thermoplastic synthetic fiber according to claim 1, wherein the thermoplastic polymer is a polyester.