JPH06200490A - Composite rope - Google Patents

Abstract

PURPOSE:To provide a high strength rope having light weight, high tenacity and sufficiently high elastic modulus, and substitutable it for metal fiber having high tenacity. CONSTITUTION:The rope is composed of >=20wt.%, based on the total weight, of polybenzoxazole fiber having tensile strength of >=4.0GPa and initial tensile elastic modulus of >=140GPa as the core material and thermoplastic synthetic resin having hydrothermal shrinkage of >=5% as the sheath.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rope suitable as an industrial rope which can be used in hot water or in a work site in a high temperature atmosphere outdoors.

[0002]

2. Description of the Related Art Conventionally, polyolefin fibers, polyvinyl alcohol fibers, polyester fibers, polyamide fibers, etc. have been used as synthetic fibers for industrial ropes.
However, when used in hot water, in the sea under hot weather, or in the desert, there was a practical problem such as a decrease in elastic modulus due to heat and a decrease in strength. Therefore, in such applications, metal wire ropes having excellent dimensional stability have been used.

However, the wire rope is difficult to handle because it has a heavy weight, is susceptible to kinking, and is too hard to bend. In order to eliminate this drawback, ropes made of aramid fiber, which has high heat resistance and high strength among synthetic fibers, have appeared.
However, although the aramid fiber rope is supple and easy to handle, it has a drawback that its outdoor use is restricted because it is not sufficiently high in water resistance and weather resistance.

Therefore, various materials having excellent weather resistance and having high strength and high elastic modulus even at high temperature have been studied. However, in each material, the raw yarn is expensive and the price which is an important selection point of rope material It was not enough.

[0005]

DISCLOSURE OF THE INVENTION The present invention is to provide a rope having high strength and high elastic modulus which is supple, easy to handle and excellent in weather resistance.

[0006]

That is, according to the present invention, the core contains 20% or more by weight of polybenzazole fiber having a tensile strength of at least 4.0 GPa and an initial tensile modulus of at least 140 GPa. A rope made of thermoplastic synthetic fiber with a shrinkage rate of boiling water of 5% or more in its sheath.

By using a polybenzazole fiber having a strength of at least 4.0 GPa and an initial elastic modulus of at least 140 GPa, a rope having high strength and being supple and light can be obtained. However, the rope made of 100% polybenzbisoxazole fiber is not only expensive, but also easily damaged by the force applied from the side of the fiber shaft, so that the performance tends to deteriorate with respect to the initial strength of the product. In addition, a material with a very high heat resistance such as polybenzazole fiber having a decomposition temperature of more than 500 ° C cannot substantially adjust the shape of the rope by heat setting, so that the texture of the rope becomes slightly stiff. It had a drawback that it was liable to come out.

Therefore, for example, the above problem can be solved by adopting a rope structure as shown in FIG. 1, that is, a structure in which the core is covered with polybenzazole fiber and the periphery thereof is covered with a thermoplastic synthetic fiber. The boiling water shrinkage of polybenzazole fiber is at most 4%, while the rope structure covered with 5% or more of thermoplastic synthetic fiber causes the shrinkage difference of both fibers in the heat setting process of the rope. Due to
The polybenzazole fiber of the core is fixed and the phenomenon of dislocation can be prevented. At that time, since the difference in elastic modulus between the thermoplastic synthetic fiber surrounding the core wire and the polybenzazole fiber is large, the reinforcing effect of the rope decreases when the fraction of the polybenzoxazole fiber is lowered. When a rope was experimentally manufactured and evaluated, the weight fraction of the polybenzooxosazole fiber was required to be at least 20%. Further, in order to provide a sufficient protective layer, it is preferable that the weight fraction of the polybenzoxazole fiber is 95% or less.

The polybenzazole fiber of the present invention is a fiber made of polybenzoxazole or polybenzthiazole, or a random or block copolymer thereof. The tensile strength is 4.0 GPa or more, preferably 4.1 GPa or more, and the initial tensile elastic modulus is 140 GPa or more, preferably 150 GPa or more.

The thermoplastic synthetic fibers used in the present invention include polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and copolymers with other acids or glycols, nylon 6, nylon 66, nylon 46 and modified fibers. Polyamide fiber or polyphenylene sulfide fiber,
Etc. The boiling water shrinkage is 5% or more, preferably 5 to 10
%.

In addition to the core polybenzoxazole fiber and the fiber of the outermost layer, a third component may be provided. For example, spun yarn or the like for impregnating electrical insulating oil can be used.

Further, in order to enhance the dimensional stability of the rope at high temperature, it is desirable to apply heat after molding to limit shrinkage. As a heating means, resin processing, steam, electric heating furnace, microwave, etc. are possible. By this treatment, the morphological stability of the rope is enhanced, and at the same time, the outer layer yarn can be reasonably tightened and the handling is good. As a measure of the effect that the morphological stability is enhanced, the amount of shrinkage of the rope length after soaking in boiling water for 1 hour is preferably 3% or less.

[0013]

EXAMPLES Hereinafter, the method for manufacturing the rope of the present invention will be specifically described with reference to examples. The strength and elongation characteristics of the raw yarn are JIS-
The method of L-1013 (1984) was followed. The strength and elongation characteristics of the rope were in accordance with the method of JIS-L-2707 (1984). The shrinkage rate of boiling water of the thermoplastic synthetic fiber arranged in the sheath was in accordance with the method of JIS-L-1013 (1992). The boiling water shrinkage of the rope was evaluated by immersing the rope marked with a laying yarn in boiling water for 60 minutes and the shrinkage amount was 50 cm.

Examples 1-5, Comparative Examples 1-4 1500 Denier Strength 4.1 GPa Elastic Modulus 155 GPa
Polybenzbisoxazole fiber is mixed into a strand to form 1500 denier strength 1.1 GPa elastic modulus 14
Table 1 shows the results of measuring the tenacity of the compound rope of GPa with polyethylene terephthalate fiber and about 4 mm as shown in FIG. It can be seen that when the weight fraction of the polybenzbisoxazole fiber is less than 20%, the reinforcing effect on the conventional material becomes extremely low.

[0015]

[Table 1]

Examples 6 to 11 Compound ropes composed of polyethylene terephthalate fibers having a polybenzbisoxazole fiber weight ratio of 40% were heat-treated in low-pressure steam at 175 ° C. Table 2 shows the results of experiments conducted by changing the amount of rope relaxation in the process. The result of observation of the rope form and the amount of rope shrinkage in boiling water (boiling water shrinkage) are shown together. The heat treatment improves the morphological stability of the rope.

[0017]

[Table 2]

A compound rope was prepared by coating polyethylene terephthalate fibers having various boiling water shrinkage ratios in the same manner as in Example 8 and evaluated. The results are shown in Table 3.

[0019]

[Table 3]

[0020]

According to the present invention, the following outstanding effects can be obtained. (1) An inexpensive high-performance rope with excellent durability can be provided. (2) The rope form can be stabilized even in a high temperature atmosphere.

[Brief description of drawings]

FIG. 1 is a rope sectional view showing an example of the present invention.

FIG. 2 is a graph showing the rope strength of the present invention.

[Explanation of symbols]

1: thermoplastic synthetic fiber (boiling water shrinkage of 5% or more), 2: polybenzazole fiber.

Claims (1)

[Claims] 1. The core has a tensile strength of at least 4.0 GP.
A rope comprising a thermoplastic synthetic fiber having a content of a or more and a tensile initial elastic modulus of at least 140 GPa or more in an amount of 20% or more by weight of the total polybenzazole fiber, and a sheath portion having a boiling water shrinkage ratio of 5% or more.