JP2003247181A - Impact-absorbing fiber rope and safety belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight impact-absorbing fiber rope excellent in strength and an impact absorbing property and a lightweight safety belt capable of remarkably reducing damage which a worker receives by dropping impact load. <P>SOLUTION: The impact-absorbing fiber rope is obtained by twisting synthetic fibers of a polyamide, together and uses a fiber having a hollow cross section, preferably the hollow cross section having four holes, having nearly cross type crosslinking part in the center part. The safety belt is obtained by using the rope. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock-absorbing fiber rope, and more specifically, a safety belt used for construction work such as a building or a steel tower, or an aerial work on an electric pole. TECHNICAL FIELD The present invention relates to a lightweight and shock-absorbing fiber rope excellent in shock-absorbing property, which is suitable as a rope for use in a vehicle.

[0002]

2. Description of the Related Art Rope made of synthetic fiber is towed,
It is well known that it is used in a wide range of industrial fields such as suspended loads, fishing, and mooring of ships, and is also used to secure the human body at construction sites, during mountaineering, disaster rescue, etc. The one with the suitable performance is used. The main use for securing the human body is as a safety belt (so-called lifeline). When performing work at high places such as building construction or steel tower construction, or electrical work using power poles, it is possible to fall due to a trivial cause and cause a fall disaster, which is a major life-threatening disaster, and prevent such a disaster. Safety belts are used to do this. You can prevent a fall if you work while wearing a safety belt.
However, there is a problem of whether the human body can withstand the impact due to the fall prevention, and this is extremely important in designing a rope for securing the human body such as a safety belt. Even in a climbing rope and a disaster rescue rope, it is necessary to consider sudden drops when the rope is attached and prevent the rope from falling.

As for the performance of the rope used for such a safety belt, it is desirable that the strength is high, but high strength is not sufficient, and when the rope is momentarily pulled with a large force at the time of blocking the fall, It is required to have a shock absorbing property capable of absorbing the shock. If the impact is large, there is a danger that the life cannot be guaranteed even if the crash is avoided. Therefore, regarding the safety belt, there is a drop test item in the "Safety Standards" of the Ministry of Health, Labor and Welfare, and it is mounted on a 75 kg sand bag and the height is 2.
Maximum load of 7.8kN when dropped from 5m
It is prescribed as follows. Generally, the higher the strength of the rope, the higher the rigidity tends to be, and it can be said that the strength and the shock absorbing property are contradictory. Currently, ropes made of synthetic fibers such as polyamide, polyester, vinylon and polypropylene are used as ropes for safety belts, and among them, considering the balance of the above required performance, strength, elongation and toughness For this reason, polyamide ropes are often used.

However, recently, in order to further reduce the load on the human body, there is a movement to strengthen the drop test items in the "safety standard" of the above-mentioned Ministry of Health, Labor and Welfare, and the strength and shock absorption at a higher level. There is a demand for high-performance ropes equipped with. Further, not only the safety belt but also the lighter one having the same performance can reduce the burden on the operator, and thus the lighter weight is also required. Therefore, it is considered that the rope, which is lightweight and has excellent strength and shock absorption, has great needs in various industrial fields other than the purpose of securing a human body such as a safety belt.

[Problems to be Solved by the Invention]

The present invention has been made in view of the above-mentioned circumstances, and is intended to provide a lightweight, shock-absorbing fiber rope excellent in strength and shock-absorbing property, as well as strong and at the same time for a drop impact load. The technical problem is to provide a lightweight safety belt that can significantly reduce the damage to the worker.

[0006]

As a result of intensive studies to solve the above problems, the inventors of the present invention knit a rope using a synthetic fiber having a hollow cross section, and The present invention has been completed by discovering the advantageous effects of not only absorbing impact but also reducing weight. That is, the present invention is a rope formed by twisting synthetic fibers, and a gist of a shock-absorbing fiber rope characterized by using a fiber having a hollow cross section as the synthetic fiber, The gist of the present invention is a safety belt characterized by using the impact absorbing fiber rope.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The light-weight impact absorbing fiber rope of the present invention is formed by twisting synthetic fibers. The type of polymer forming the synthetic fiber is not particularly limited, and polyamide, polyester, vinylon, polypropylene, etc., which are commonly used for ropes, can be used, but they have an excellent balance of fiber strength and impact absorption. Polyamide is preferred in that respect. Examples of the polyamide include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, and polyamide 610. These can be used alone, or copolymerized or blended. Of these, polyamide 6 is preferable because it is inexpensive and has excellent strength and durability. The synthetic fiber may contain a matting agent, a modifier, an antistatic agent, a pigment and the like as long as the object of the present invention is not impaired. The fiber form is preferably filament yarn.

The most important thing in the present invention is to use synthetic fibers having a hollow cross section as synthetic fibers constituting the rope. By having a hollow cross section, the impact applied to the rope is absorbed by the hollow portion, and if the rope has the same thickness, it can be finished to be lightweight. In addition, having a hollow cross section means having at least one hollow portion in a cross section perpendicular to the length direction of the fiber, that is, in a cross section.

The number of hollow portions in the hollow cross section is as follows:
Although not particularly limited, it is preferable that there are a plurality of fibers from the viewpoint of maintaining the fiber strength and preventing collapse during rope knitting or shock absorption, and the action of the cross-linking portion existing between the hollow portions. As a result, not only shock absorption but also fiber strength and shape retention of the hollow portion are excellent.
The number and arrangement in the case of having a plurality of hollow portions can be appropriately designed so that strength, shape retention and impact absorption can be effectively exhibited.
As schematically shown in FIG. 3, the cross-sectional shape has four hollow portions so as to form the cross-shaped bridge portion in the vicinity of the central portion. Since the cross-linking portion has a cross shape, the resistance to stress from multiple directions becomes high, and by using such a fiber, a fiber rope that absorbs impact more effectively can be obtained.

Further, a synthetic fiber having a hollow cross section (hereinafter,
The hollowness of (sometimes abbreviated as hollow fiber) is 1
0 to 35% is preferable, 15 to 30% is more preferable,
18 to 25% is particularly preferable. If the hollow ratio is less than 10%, the effect of shock absorption by the hollow portion is small, which is not preferable, while if it exceeds 35%, the hollow portion tends to be crushed, which is not preferable. The hollow ratio means the ratio of the area of the hollow portion to the area of the cross section of the fiber (including the area of the hollow portion).

Although it is a physical property of the hollow fiber, the tensile strength thereof is preferably 7.0 cN / dtex or more, and the intermediate elongation under a load of 4.73 cN / dtex is preferably 10% or more. The cutting elongation is preferably 20 to 30%, and 110
The heat shrinkage stress at 0 ° C is 0.15 cN / dte.
It is preferably x or less. The tensile strength of the fiber is preferably 7.0 cN / dtex or more,
This is because the rope can be sufficiently strong. 4.73
It is preferable that the intermediate elongation at a load of cN / dtex is 10% or more, because the impact when blocking the fall of the human body with the rope attached thereto can be effectively absorbed by the extension of the rope. Is. Cutting elongation of 30
% Or less is preferable because the rope can be prevented from extending too much, and 20% or more is preferable because the impact can be effectively absorbed even when the rope is extended. Further, the reason why the heat shrinkage stress at 110 ° C. is preferably 0.15 cN / dtex or less is that it is possible to prevent the rope from being overtightened and hardened due to the heat treatment at the time of manufacturing the rope to reduce the impact absorbability.

The impact absorbing fiber rope of the present invention includes:
In order to effectively exhibit shock absorption and lightness, it is preferable that the hollow fiber is mainly composed of the above hollow fiber, and it is most preferable that the hollow fiber is composed only of the hollow fiber. However, if the use of hollow fibers is within the range where the improvement of the main object of the present invention of impact absorption is obtained,
There is no problem in using fibers other than hollow fibers in combination, and the present invention does not exclude such an aspect.

Further, in the shock absorbing fiber rope of the present invention, it is also preferable that a part of the fibers constituting the rope is impregnated with a resin. When a part of the fiber is impregnated with resin, the abrasion resistance of the rope is improved, the twisting of the rope is less likely to occur, and the rope has an appropriate stiffness, so it is easy to handle, and it is also suitable for Satsuma processing. It will be easier. As a mass ratio when impregnated with a resin, it is preferable that the fibers are impregnated with a resin having a mass of 20 to 60% with respect to the mass of all the fibers constituting the rope. Here, the mass of all fibers means the mass before resin impregnation. If the resin impregnation ratio is less than 20%, it is difficult to obtain the resin impregnation effect. On the other hand, if it exceeds 60%, the rope is cured and the impact absorbability is lowered, which is not preferable. Examples of resins used for resin impregnation include acrylic resins, vinyl acetate resins, and polyester resins, with acrylic resins being preferred.

The shock absorbing fiber rope of the present invention has a shock absorbing property of a maximum shock load of 7 which is the maximum load applied to the rope when the rope is mounted in an 85 kg sand bag and dropped from a height of 3 m. It is preferably 0.0 kN or less. This is to reduce the damage to the human body etc. where the rope is attached. At this time, the rope attachment method and other measurement methods are in accordance with the drop test items in the "Safety Standards" of the Ministry of Health, Labor and Welfare regarding safety belts. In addition, other characteristics that the shock absorbing fiber rope of the present invention has include:
Depending on its thickness and application, for example, a rope with a diameter of 10 mm has a tensile strength of 17 kN or more and a breaking elongation of 45.
% Or less is preferable. If the tensile strength is less than 17 kN, it may not be able to withstand the impact of a human body falling, which is not preferable for use in securing a human body such as a safety belt.
Further, if the cutting elongation exceeds 45%, the elongation may be too large to absorb the drop impact, which is not preferable.

Next, a method for producing the shock absorbing fiber rope of the present invention will be described. First, a method for producing hollow fibers used to construct a rope will be described by taking polyamide hollow fibers as an example. As the polyamide, various polyamides such as polyamide 6 can be used, but it is preferable to add a bisamide compound having a long-chain alkyl group to the polyamide. Examples of the bisamide compound include metaxylylenebisstearylamide, metaxylylenebisoleylamide, ethylenebisstearylamide, and the like, and ethylenebisstearylamide is particularly preferable. By adding these bisamide compounds, the shape of the hollow portion of the hollow fiber is easily maintained during spinning. The addition amount of these bisamide compounds is preferably 0.01 to 1.0% with respect to the mass of polyamide, and 0.05 to 1.0%.
0.2% is particularly preferred.

As the spinning device, a normal spinning device can be used, and a nozzle designed to obtain a desired hollow cross-sectional shape may be used.

As the spinning step, either a one-step method in which spinning is followed by stretching or a two-step method in which an unstretched yarn is once wound and then stretched may be adopted, but from the viewpoint of productivity. It is preferable to adopt the one-step method. In the case of the one-step method, after the melt-spun yarn is cooled and solidified, an oil agent is applied, and while being taken up by a plurality of rollers whose temperature is set to 100 to 200 ° C., the total draw ratio is 3.5 to 6 times. And draw at a winding speed of 2000-4000.
Wind up at m / min. In the case of the two-step method, the melt-spun yarn is cooled and solidified, then an oil agent is applied, and the undrawn yarn is
Wind up at 800 m / min. After that, the undrawn yarn is heated at a temperature of 170 to 200 with a drawing machine provided with a heat treatment heater between the rollers.
While heating at 0 ° C., it is hot-stretched at a draw ratio of 4 to 6 and wound up. In either case of the above-mentioned one-step method or two-step method, in order to prevent the occurrence of yarn breakage and fluff during drawing and to obtain fibers having excellent strength characteristics, the oil agent applied after cooling and solidification is a non-aqueous oil agent. Is preferred.

By using the hollow fiber obtained as described above, the impact absorbing fiber rope of the present invention can be manufactured, for example, as follows. First, a plurality of fibers are twisted together to produce a ring yarn. A plurality of the obtained ring yarns are further twisted to produce a rope yarn.
At this time, the twisting direction is opposite to that at the time of producing the ring yarn. A plurality of the obtained rope yarns are twisted in a direction opposite to the twisting direction of the rope yarn to prepare a strand yarn, and a plurality of strand yarns are twisted in a direction opposite to the twisting direction of the strand yarn to obtain a raw rope. Then, by heat-treating this raw rope, the impact absorbing fiber rope of the present invention can be obtained.

When the resin impregnation is performed, the rope yarn obtained by twisting the ring yarns is resin-impregnated by a conventional method when the strand yarn is produced during the above-mentioned rope manufacturing process, and the resin is impregnated with the rope yarn. It is preferable to twist a rope yarn that is not present to form a strand yarn. The ratio of the resin-impregnated rope yarn to the strand yarn is preferably 1/3 to 1/2.

[0020]

EXAMPLES Next, the present invention will be specifically described by way of examples. The characteristics of the raw materials used in the examples or the obtained ropes were measured or evaluated by the following methods. (1) Relative viscosity of polyamide 96 wt% Sulfuric acid was used as a solvent, and the sample concentration was 1 g / 100 m.
It was measured by a conventional method under the conditions of 1 and temperature of 25 ° C. (2) Tensile strength of fiber, intermediate elongation, breaking elongation Using an AG-B type autograph manufactured by Shimadzu Corporation,
It was measured at a sample length of 250 mm and a pulling speed of 300 mm / min. (3) Heat shrinkage stress of fiber It was measured at a heating rate of 100 ° C./min using a KE-2S type heat shrinkage stress machine manufactured by Kanebo Engineering Co., Ltd. (4) Fiber Hollowness A microphotographing device was attached to a Nikon Microphoto S optical microscope, the cross-sectional shape of the fiber was photographed, and the values of the total area A of the hollow portion and the area B of the non-hollow portion were calculated. Was calculated by the following formula. Hollow ratio (%) = {A / (A + B)} × 100 (5) Tensile strength and breaking elongation of the rope are measured by JI using a tensile tester manufactured by Tokyo Test Machine Co., Ltd.
Measured according to SL 2704. (6) The maximum impact load of the rope The rope was attached to a sand bag having a maximum load of 85 kg and dropped from a height of 3 m, and the maximum value of the load applied to the rope was measured by an oscillograph. (7) Rope linear density The rope linear density was measured according to JIS L 2704.

Example 1 To 100 parts by mass of pellets of polyamide 6 having a relative viscosity of 3.5 was added 0.1 part by mass of ethylenebisstearylamide, which was supplied to an extruder, melt-spun at a spinning temperature of 280 ° C., and spun. One-step method in which the yarn is cooled and a non-aqueous oil agent is applied, and then hot drawing is carried out at a total draw ratio of 4.9 times between hot rollers having a roller temperature of 180 ° C. and wound at a winding speed of 2500 m / min. Thus, a polyamide hollow fiber (1100 dtex, 68 fil) having a four-hole hollow cross section as shown in FIG.
Multifilament) was obtained. The strength of this fiber is 7.
9 cN / dtex, intermediate elongation at 4.73 cN / dtex load was 12.7%, cutting elongation was 24.5
%, And the heat shrinkage stress at 110 ° C. is 0.10 cN
/ Dtex, and the hollow ratio was 21.7%. Ten multifilaments thus obtained were twisted at a Z twist of 50 T / M to produce a ring yarn. Then, 12 of the ring yarns were twisted with an S twist of 50 T / M to produce a rope strand. In addition, Z these three rope strands
A raw rope was formed by twisting with a twist of 33 T / M. Then, this raw rope is subjected to high-frequency heat treatment at 110 ° C, and the diameter is 10 m.
m impact-absorbent fiber rope of the invention was obtained.

Comparative Example 1 To 100 parts by mass of pellets of polyamide 6 having a relative viscosity of 3.5 was added 0.1 part by mass of ethylenebisstearylamide, which was supplied to an extruder and melt-spun at a spinning temperature of 280 ° C.
After the spun yarn is cooled and a non-aqueous oil agent is applied, it is heat-stretched at a total stretching ratio of 4.8 times between heat rollers having a roller temperature of 180 ° C. and wound at a winding speed of 2600 m / min. Depending on the process method, the polyamide fiber (1
400dtex, 210fil multifilament)
Got The strength of this fiber was 8.2 cN / dtex, and the intermediate elongation under a load of 4.73 cN / dtex was 10.
0%, the cut elongation was 17.2%, and the heat shrinkage stress at 110 ° C was 0.10 cN / dtex.
Eight multifilaments thus obtained were twisted at a Z twist of 70 T / M to produce a ring yarn. Then, 12 of the ring yarns were twisted with an S twist of 60 T / M to produce a rope strand. Further, three of these rope strands were twisted with a Z twist of 20 T / M to obtain a raw rope. And
This raw rope is subjected to induction heat treatment at 110 ° C to obtain a diameter of 10
A mm rope for comparison was obtained. The properties of the ropes obtained in Examples and Comparative Examples are shown in Table 1 below.

[0023]

[Table 1]

As is clear from Table 1, the rope of Example 1 of the present invention is excellent in mechanical properties as a rope, particularly has a small maximum impact load and excellent impact absorption performance, and is suitable for safety belts. It was a suitable shock absorbing fiber rope. Further, as is clear from the linear density, it was excellent in lightness. In addition, when actually making a safety belt, the workability and handleability were excellent, and the usability was good. On the other hand, the rope of Comparative Example 1 had a high fiber strength, but was inferior in impact absorbability, and had a large mass, as can be seen from the value of linear density.

[0025]

EFFECTS OF THE INVENTION The impact absorbing fiber rope of the present invention can be made not only to absorb impact by the action of the hollow portion but also to be lightweight by knitting the rope using a synthetic fiber having a hollow cross-sectional shape. . Therefore, it is particularly suitable for use in securing a human body such as safety belts and sails, and can be widely used for applications requiring shock absorption regardless of fields, such as towing, hoisting, fishing, and mooring of ships.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of the cross-sectional form of a hollow fiber used in the present invention.

[Explanation of symbols]

1. Hollow part 2. Bridge

Continued front page    F-term (reference) 2E184 JA03 KA01 KA09 KA11 KA17                       LA02 LA14 LA23 LA33                 3B153 AA02 AA47 BB20 CC22 FF01                       FF17 FF18 FF23 FF42 GG17                 4L035 BB31 BB59 BB77 BB89 BB91                       CC01 DD05 EE01 EE08 EE20                       FF01 HH10 JJ20 KK05 LC02

Claims (6)

[Claims] 1. A shock-absorbing fiber rope, which is a rope formed by twisting synthetic fibers, wherein a fiber having a hollow cross section is used as the synthetic fiber. 2. The shock-absorbing fiber rope according to claim 1, which has a plurality of hollow portions in a hollow cross section. 3. The shock absorbing fiber rope according to claim 2, wherein the hollow cross section has four hollow portions so as to form a cross-shaped cross-linking portion near the center. 4. The shock absorbing fiber rope according to claim 1, wherein the synthetic fiber is a polyamide fiber. 5. The impact absorption according to any one of claims 1 to 4, wherein the fibers are impregnated with a resin having a mass of 20 to 60% with respect to the mass of all the fibers constituting the rope. Sex fiber rope. 6. A safety belt comprising the impact absorbing fiber rope according to any one of claims 1 to 5.