JPH02154010A - Fiber for sling and sling - Google Patents

Abstract

PURPOSE:To obtain the subject fiber of constant quality excellent in high strength and high durability and having improved dimensional stability by using a polyester the main component of which is ethylene terephthalate as the core component and a polyamide as the sheath component. CONSTITUTION:The objective fiber is composed of (A) 30-90wt.% core compo nent consisting of a polyester (e.g. >=0.8 intrinsic viscosity, 160 X 10<-3>-190 X10<-3> birefringence eta, >= 1.380g/cm<3> density, >=247 deg.C melting peak temperature by DSC) the main component of which is ethylene terephthalate and (B) the sheath component consisting of a polyamide (e.g. >=2.8 relative viscosity to sulfuric acid etar, >=50 X 10<-3> birefringence and >=1.140g/cm<3> density) as the main component and has >=7.5g/d strength, <=20% elongation and >=60g/d initial resistance to stretching.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a sling suitable for use as a sling wrapped around a suspended object when the suspended object is lifted and moved by a crane, hoist, etc. and a sling obtained using the fiber.

[Conventional technology]

Conventionally, tM! used for slings. Polyamide fibers, polyester fibers, etc. are known as IT fibers, and by combining the above polyamide fibers and polyester fibers, the polyamide fibers with excellent abrasion resistance are arranged on the outer periphery of the sling, and the polyester fibers with low elongation are arranged on the center part. Japanese Utility Model Publication No. 53-14777 discloses a sling consisting of a double-woven belt whose central part and outer periphery have different colors in order to easily identify wear on the outer periphery. Publication, Utility Model Publication No. 53-29811, Utility Model Publication No. 58-348
It is known from Publication No. 71.

[Problem to be solved by the invention]

The above-mentioned Utility Model Publication No. 14777, Utility Model Publication No. 53-2
In the case of the slings described in Japanese Utility Model Publication No. 9811 and Japanese Utility Model Application Publication No. 58-34871, two different types of fibers, polyamide fibers and polyester fibers, are used. The problem was that it didn't.

In addition, using two types of 100% fibers in the - process may cause troubles such as contamination of fibers, such as polyamide fibers being contaminated with polyester fiber creel, and the sling obtained with this contamination will be a substandard product. The disadvantage is that the quality is not constant, and the sling in this case is not of practical use.

Furthermore, the two types of fibers in the prior art mentioned above are polyester fibers in the center of the sling! Polyamide fibers are placed on the outer periphery of the sling to maintain the strength of the entire sling! However, the strength and durability are separated, making it difficult to maintain sufficient strength and durability in the entire sling.
The strength retention of polyamide fibers and the durability retention of polyester fibers tend to deteriorate, and the life of the sling ultimately depends on the characteristics of one of the fibers.

An object of the present invention is to solve the problems of the prior art described above and to provide fibers for slings that have high strength and excellent durability.

Another object of the present invention is to provide a sling that is highly strong and highly durable.

[Means and effects for solving the problems] The constitution of the present invention is as follows: (1) A fiber for a sling, the fiber having a core component of polyester containing ethylene terephthalate as a main component;
It is a core-sheath type conjugate fiber in which a sheath component mainly composed of polyamide is arranged around the core component, and the proportion of the core component made of the polyester in the conjugate fiber is 30 to 90% by weight. A fiber for slings characterized by having a strength of 7.5 g/d or more, an elongation of 20% or less, and an initial tensile resistance of 60 g/d or more, (2) the composite according to (1) above. The polyester that forms the core component of the fiber has an intrinsic viscosity [η] of 0.8 or more, a birefringence of 160X10-3 to 190X10-3, and a density of 1.38.
0g/cm3 or more, the melting peak temperature measured by DSC is 247℃ or more, the sulfuric acid relative viscosity [ηr] of the polyamide forming the sheath component is 2.8 or more, and the birefringence is 50X10.
-3 or more, and a density of 1°140g/cm3 or more; (3) A sling, characterized in that the fibers described in (2) above are made into a multi-layered fabric. .

The contents and effects of each element constituting the present invention will be explained in detail below.

The composite fiber for sling according to the present invention is made of conventional polyamide! This is something that could not be obtained with 1lli fiber, polyester fiber, or their composite fiber technology, and has a high modulus close to that of polyester, a durability close to that of polyamide,
and peeling durability of the polymer at the core-sheath interface, and the composite fiber has properties of strength of 7.5 g/d or more, elongation of 20% or less, and initial bowing resistance of 60 g/d or more.

These properties are based on the specified physical properties of the polyester and polyamide fibers forming the core and sheath, namely, the intrinsic viscosity [η] of the polyester forming the core component is 0.8 or more, and the birefringence is 160X10-3 to 190X10-3. , the density is 1.
380 g/cm3 or more, the melting peak temperature measured by DSC is 247°C or more, the sulfuric acid relative viscosity [ηr] of the polyamide forming the sheath component is 2.8 or more, and the birefringence is 50
This can be indicated by X10-3 or more and a density of 1.140 g/cm3 or more.

The polyester serving as the core component of the composite S[ is preferably a polyester consisting essentially of polyethylene terephthalate units. An amount that does not substantially reduce the physical and chemical properties of the polyethylene terephthalate polymer, e.g. 10
% of the copolymerized component may be included. Copolymerization components may include dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid and diphenylcarboxylic acid, and diol components such as ethylene oxide, butylene glycol and butylene glycol.

The core component polyethylene terephthalate (1) fiber for obtaining a composite i-fiber strength of 7.5 g/d or more has a high intrinsic viscosity [η] of 0.7 or more, preferably 0°8 or more.

On the other hand, the polyamide that becomes the sheath component is made of ordinary polyamides such as polycabramide, polyhexamethylene adipamide, polytetramethylene adipamide, polyhexamethylene adipamide, polyhexamethylene dodecamide, etc. Methylene adipamide type is preferred.

Similar to the polyester core component, the polyamide sheath component polymer also requires a high degree of polymerization in order to obtain a high-strength conjugate fiber, and the relative viscosity of the sulfuric acid is 2.8 or more, preferably 3.0 or more.

The ratio of the polyester core component of the composite fiber is 30 to 9.
It is 0% by weight. If the polyester core component is less than 30% by weight, a composite fiber that can effectively utilize the high modulus of the polyester component cannot be obtained, and a preferred fiber for slings cannot be obtained.

On the other hand, if the polyester core component accounts for 90% by weight or more, the durability of the polyamide sheath component cannot be sufficiently exhibited, making it impossible to obtain a preferred fiber for a sling.

In the composite fiber, both the polyester core component and the polyamide sheath component are highly oriented and crystallized, and the polyester core component has a birefringence of 160X10-3 to 190X10-3.
It is 3. If it is less than 180X10-3, the strength of the composite fiber may not be 7.5 g/d or more, and the initial tensile resistance may not be 60 g/d or more.On the other hand, if it exceeds 190X10-3, fatigue resistance may deteriorate. .

On the other hand, the birefringence of the polyamide sheath component is 50×1□−3 or more, which is highly oriented. If the birefringence is 50 x 10-3, it is difficult to obtain a composite fiber with high strength and high modulus.

The birefringence of the core-sheath composite III can be measured as follows. That is, the sheath portion is directly measured using a transmission interference microscope, and the core portion is measured using a transmission interference microscope after dissolving the polyamide sheath component in formic acid, sulfuric acid, fluorinated alcohol, or the like.

The polyester core component has a density of 1.380 g/cm3 or more, the polyamide sheath component has a density of 1.140 g/am3 or more, and is highly crystallized.

If the density is not above the above-mentioned specific value, the fatigue resistance of the composite fiber will not be significantly improved, and a preferred fiber for slings will not be obtained.

The density of the polyester core component is measured by dissolving and removing the polyamide sheath component with formic acid, Vt acid, fluorinated alcohol, etc., and the density of the polyamide sheath component is calculated from the density of the composite fiber and the density of the polyester core. .

DSC showing the characteristics of the crystal structure of the polyester core component
The melting peak temperature of is 247°C, preferably 248°C.
This is a high temperature. The higher the peak temperature, the larger the crystals and/or the better the crystal integrity, which corresponds to a more stable fiber structure. If the melting peak temperature of the polyester core component is 247°C, the desired modulus may not be obtained, and a desirable fiber for slings may not be obtained.

The conjugate fiber characterized as described above has a high strength of 7.5 g/d or more, an initial tensile resistance of 60 g/d or more, and an elongation of 20% or less, so that a preferred fiber for slings can be obtained.

The composite fiber is manufactured by the novel method shown below.

In order to obtain the above-mentioned polymer physical properties of the polyester core component, a polymer consisting essentially of polyethylene terephthalate and having an intrinsic viscosity [η] of 0.75 or more, usually 0.85 or more is used.

As the polyamide sheath component polymer, a high polymerization degree polymer having a Wit acid relative viscosity of 2.8 or more, usually 3.0 or more is used.

It is preferable to use two extruder type spinning machines for melt spinning the polymer. The polyester and polyamide polymers melted by each extruder are introduced into a composite spinning pack, and spun into a composite fiber with polyester in the core and polyamide in the sheath through a composite spinning nozzle.

The spinning speed is 1000 m/min or more, preferably 1500 m/min.
The speed should be at least 1/min. Immediately below the spinneret, there is a waft of 10 cm or more, and within 1 m, a waft of 200'C or more, preferably 26
A heating atmosphere of 0°C or higher is created by providing a heat insulating cylinder and a heating cylinder. After passing through the above-mentioned heating atmosphere, the spun yarn is quenched and solidified with cold air, then applied with an oil agent, and then taken off by a take-off roll that controls the spinning speed. Control of the heating atmosphere directly below the spinneret is important in order to maintain spinnability during high-speed spinning. The undrawn yarn that has been bowed is usually drawn continuously without being wound up, but it can also be drawn in a separation step after being wound up. The birefringence of the undrawn yarn sampled on a take-up roll in order to understand the physical properties of the undrawn yarn before stretching was 20XIO-3 or higher for the polyamide sheath, and 20XIO-3 or higher for the polyester core, indicating that it was highly oriented. are doing.

The adoption of high-speed spinning has the effect of improving the modulus of the composite fiber, but what is even more surprising is that the durability of the core-sheath composite interface is significantly improved.

Unlike the conventional low-speed spinning method, in which a highly hygroscopic and crystallized polyamide component is combined with an amorphous polyester component, in the high-speed spinning method, the polyamide component,
It is thought that the fact that both the polyester components are in a state where oriented crystallization progresses, and that the stretching ratio after spinning is small can contribute to the durability of the composite interface.

Next, the undrawn yarn is heated to a temperature of 180°C or higher, preferably 200°C.
It is hot stretched at a temperature higher than that. Stretching is done in 2 or more stages, usually 3
The stretching is carried out in multiple stages, and the stretching ratio is in the range of 1.4 to 3.5 times. The use of high-temperature hot stretching according to the present invention also contributes to improving the composite interface durability. If the stretching temperature in the third stage of the stretching is low, for example 160° C., interfacial peeling between the polyester core component and the polyamide sheath component may often occur due to stretching.

Using the composite fiber thus obtained, a multilayer fabric is produced into a sling. The structure of the multilayer fabric may be a generally known structure.

A sling manufactured using the composite fiber has sufficient strength and is highly durable.

〔Example〕

Examples 1, 2) Comparative Examples 1, 2 Intrinsic viscosity [η)], 05, carboxyl end group concentration 10
, 5eq/106g of polyethylene terephthalate) (
PET) and polyhexamethylene adipamide (N66
, sulfuric acid relative viscosity ηr3.3), or copolymer polyamide of hexamethylene diammonium adipate and hexamethylene diammonium terephthalate (66/6T:
Copolymerization ratio 80:20 weight ratio) were respectively melted in a 40φ spinner type spinning machine and introduced into a composite spinning pack.
A composite yarn with polyethylene terephthalate in the core and polyamide in the sheath was spun from a core-sheath composite spinneret. The proportions of the core and sheath components were varied as shown in Table 1.

The cap used had a hole diameter of 0.4 mmφ and 120 holes.

Polymer temperature is 295℃ for polyethylene terephthalate.
and polyamide were melted at 290°C and spun at a spinning back temperature of 300'C. 15c right below the base
A heating cylinder of m was attached, and the atmosphere inside the cylinder was heated to 290°C. Ambient temperature is 10cI from the mouth surface.
This is the ambient temperature measured at a position below n and at a position 1 cm away from the outermost circumferential yarn. There is a length of 40a under the heating cylinder.
Attach a circular chimney of 25°C to 25°C from the circumference of the yarn.
The yarn was cooled by blowing cold air at 40 m/min at right angles to the yarn. After controlling the yarn speed with a take-up roll rotating at the speed shown in Table 1, the yarn was drawn continuously without being wound up. The film was stretched in three stages using five pairs of Nelson type rolls, then subjected to a relaxation heat treatment with 3% relaxation, and then wound up. The stretching conditions were as follows: the take-up roll temperature was 60°C.
Stretching roll temperature is 1.20°C, 2nd stretching roll temperature is 190°C, 3rd stretching roll temperature is 225°C, the tension adjustment roll after stretching is not heated, and the 1st stage stretching ratio is the total stretching ratio. 70% of the total and the remainder were divided into two stages and stretched. The yarn was produced by varying the spinning speed, total draw ratio, etc., and the discharge amount was changed in accordance with the spinning speed and draw ratio so that the fineness of the drawn yarn was about 500 denier. The obtained drawn yarn is 2
This yarn was doubled to give I 000 denier.

In Comparative Examples 1 and 2, the birefringence of the polyester forming the core component of the composite fiber, which is a component of the present invention, is 160X10-
3 to 190X10-3, and the melting peak temperature measured by DSC does not satisfy the range of 247°C or higher.

Next, multiple fabrics were woven into slings using these drawn yarns, and the toughness and durability of the slings were evaluated. The results are also listed in Table 1.

In addition, the performance of the sling is 1 when the sling is bent at a 90 degree angle.
Judgment was made after bending fatigue for 000 minutes.

◎ indicates extremely good, O indicates good, and Δ indicates a problem.

As is clear from the results in Table 1, the slings woven using composite fibers satisfying the constituent requirements of the present invention were excellent in toughness and durability.

〔Effect of the invention〕

The fiber for slings according to the present invention has a modulus equal to or higher than that of conventional polyester, and has excellent dimensional stability and durability.

Further, the sling according to the present invention has extremely good durability by using the sling fiber.

Furthermore, since it is possible to manufacture products using only one type of fiber, it is possible to prevent troubles such as mixing of different types of fibers, and it is easier to maintain constant quality.

Claims (3)

[Claims] (1) In the fiber for sling, the fiber has a core component of polyester containing ethylene terephthalate as a main component,
It is a core-sheath type conjugate fiber in which a sheath component mainly composed of polyamide is arranged around the core component, and the proportion of the core component made of the polyester in the conjugate fiber is 30 to 90% by weight. A fiber for slings having a strength of 7.5 g/d or more, an elongation of 20% or less, and an initial tensile resistance of 60 g/d or more. (2) In claim 1, the polyester forming the core component of the composite fiber has an intrinsic viscosity [η] of 0.8 or more and a birefringence of 160 x 10^-^3 to 190 x 10^-
^3, the density is 1.380 g/cm^3 or more, the melting peak temperature measured by DSC is 247°C or more, the sulfuric acid relative viscosity [ηr] of the polyamide forming the sheath component is 2.8 or more, and the birefringence is 50×10^-^3 or more, density 1.14
A fiber for slings characterized by having a weight of 0 g/cm^3 or more. (3) A sling characterized in that it is made of a multilayer fabric made of the fibers described in claim 2.