JPS6385105A - Organic high-strength yarn with excellent abrasion resistance - Google Patents

Abstract

PURPOSE:To produce the titled yarn having a high strength, a high elastic modulus and excellent flexural abrasion resistance and useful for producing ropes, hoses, fishing nets, etc., comprising filaments having a melting point, a tensile strength and a tensile modulus of higher than specific respective levels and also having a flexural abrasion strength of higher than a specific level. CONSTITUTION:The objective yarn comprises filaments having a melting point of >=160 deg.C, a tensile strength of >=15kg/d, preferably >=20g/d and a tensile modulus of >=300g/d, preferably >=350g/d and also having a flexural abrasion strength of >=2,000, preferably >=3,500. The yarn is preferably composed essentially of PVA.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an organic high-strength fiber with excellent abrasion resistance, particularly for use in industrial materials such as ropes, hoses, seat belts, sewing threads, fishing nets, and marine materials. This invention relates to high-strength fiber materials with excellent abrasion resistance.

[Prior art] Various techniques for obtaining organic high-strength fibers have been studied in the past.
It is known that arranging polymer molecular chains in the fiber axis direction is effective in increasing strength and elastic modulus.

For example, in the spinning process of nylon fibers and polyester fibers, by increasing the stretching ratio in the drawing process, the tensile strength and tensile modulus of the drawn yarn obtained by 1q can be increased. This is because stretching increases the degree of molecular chain orientation in the crystalline and non-crystalline parts of the fiber.

In addition, it is well known that loosely oriented aramid fibers can be spun from a spinneret, removed from the solvent, and taken as is, and then subjected to a drawing process to achieve high strength and elastic modulus ( For example, Japanese Patent Publication No. 47-2489). This is because the spinning stock solution forms a liquid crystal structure under certain conditions, and when it is extruded from the hole in the spinneret, the liquid crystals align in the fiber axis direction due to shear stress.

It is believed that as a result, the polymer molecular chains are well oriented in the fiber axis direction through the stretching process.

Recently, after melt-spinning aromatic copolyester (polyarylate), which forms a liquid crystal structure when heated and melted, to form fibers with a high degree of molecular chain orientation,
It is also known that 1q of fibers with high strength and high elastic modulus can be obtained by heating in an inert atmosphere for a long time and proceeding with solid phase polymerization (for example, 1 q of fibers with high strength and high modulus of elasticity can be obtained).
Publication No.). The MA formation of this fiber can be understood in almost the same way as the above-mentioned aramid fiber.

Problems to be Solved by the Invention According to the above-mentioned fiberizing means, especially liquid crystal spinning, organic fibers having significantly higher strength and modulus of elasticity than conventional general-purpose synthetic fibers can be produced. In both cases, the linear polymer molecular chains are extremely one-dimensionally arranged in the fiber axis direction.
Only weak intermolecular forces act in the direction perpendicular to the fiber axis,
Since the binding force is small, the fiber structure is weak in the transverse direction. Therefore, in order to increase the strength and modulus of elasticity, the higher the degree of orientation of the polymer molecular chains, the more fibrils will develop in the fiber axis direction, and since the interaction between fibrils is small, repeated bending deformation and friction will occur. In applications where the product is used under heavy loads, durability becomes a problem.

Nylon fibers and polyester fibers are relatively susceptible to bending deformation,
It has excellent durability compared to polyester fibers, but its strength and modulus of elasticity are significantly lower than those of para-oriented aramid fibers.

In the field of industrial materials such as ropes, hoses, seat belts, sewing thread, and fishing nets, fiber materials with significantly higher strength and elasticity than conventional general-purpose fibers (nylon, polyester, vinylon, and acrylic) are required. Various high-strength fiber materials have been developed to meet this demand, but as mentioned above, all of them have problems with durability when used in situations where they are subjected to repeated bending deformation or frictional loads.

An object of the present invention is to eliminate the above-mentioned problems of the prior art and to provide an organic 41i fiber made of filaments that has significantly higher tensile strength than general-purpose fibers and excellent bending abrasion resistance.

[Means for Solving the Problems] The present invention has a melting point of 160'C or more, a tensile strength of 15 g/d or more, a tensile modulus of 300 a/d or more, and a flexural abrasion strength. This article relates to organic high-strength fibers with excellent abrasion resistance and consisting of filaments with a molecular weight of 2,000 or more.

In other words, when the spinning dope (solution or melt) has a liquid crystal structure, such as the para-oriented aramid or polyarylate, the fiber obtained by spinning has a structure in which columnar fibrils are concentrated, and the fibrils are in the form of independent fibrils. As a result, a force is applied from the side to the fiber axis. Or, when a compressive force is applied in the axial direction, it tends to crack or buckle in the axial direction. For example, the structural model of polyparaphenylene terephthalamide fiber as proposed by Yabuki et al. [Journal of the Japan Institute of Fiber Science and Technology, Vol. 31. No, 11. T-528 (1
975)], the structure of fibers obtained by liquid crystal spinning is weak against loads in the transverse direction to the fiber axis. As a result of intensive research into strengthening the bonds between fibrils, we selected a polymer species with relatively strong intermolecular forces in order to strengthen the bonds between the molecules within the fibrils and between the fibrils.

■Increase the molecular weight of the polymer to increase the degree of molecular chain penetration of fibrils.

■Increase the polymer concentration in the spinning stock solution in order to appropriately increase the entanglement between molecules, slow down the desolvation rate, and form a dense fiber structure.

By skillfully combining these three elements,
The fiber of the present invention is obtained.

The polymer in the present invention has a tensile strength of 15 c+
/d or more, preferably 18 g/d or more, more preferably 20 c+/d or more, a tensile modulus of 300 g/d or more, preferably 350 q/d or more, and a flexural abrasion strength of 20
00 or more, preferably 3000 or more.

More preferably, in order to form fibers of 3,500 or more, a polymer with particularly strong intermolecular force, such as a polyamide system, is used.

Examples include polyester polymers, polyvinyl alcohol polymers, and the most preferred polymer is highly crystalline polyvinyl alcohol polymers.

Further, in order to make the melting point of the fibers 160°C or higher, a polymer having a melting point of 150°C or higher should be selected. In other words, when organic high-strength fibers are used for various industrial material applications, they are often heated during processing and use. was set at 160°C or higher.

In addition, in the present invention, in order to make the tensile strength of the fiber as high as possible, a material having a high molecular weight is used as the raw material polymer, for example, a number average molecular weight of 1×105°, preferably 1.5×1
Use one that exceeds 05.

In order to spin this type of polymer, the viscosity of the melt is extremely high in the melt spinning method, making it difficult to spin the material stably. For this reason, it is necessary to dissolve it in a certain kind of solvent to lower the spinning viscosity, that is, to use solution spinning.

Conventionally, there are two methods for solution spinning: dry spinning and wet spinning. In dry spinning, the polymer concentration in the spinning dope is as high as possible, for example, 35%, in order to speed up solvent removal under the spinneret. However, since a polymer with a high molecular weight is used, the viscosity of the stock solution suitable for dry spinning is too high, making spinning difficult.

On the other hand, in conventional wet spinning, increasing the polymer concentration of the spinning stock solution reduces the desolvation rate and creates a dense @
It is known that a coagulated thread with a structure can be obtained, but because the ferrule is in the coagulation bath.

The spinning temperature cannot be increased, and therefore, the spinning dope using a high molecular weight polymer has a high viscosity, resulting in extremely poor spinning properties.

These obstacles placed the spinneret outside the coagulation bath. This problem can be solved by adopting the so-called wet-dry spinning method.

In other words, in the ``wet-dry spinning method,'' by separating the spinning dope discharge part from the coagulation bath, it is possible to set the temperature of the spinning dope independently of the coagulation bath, so the temperature can be set relatively freely and high. be able to.

Therefore, in the dry-wet spinning method, the spinning temperature can be set appropriately high in order to appropriately lower the viscosity of a high-concentration spinning dope using a high molecular weight polymer.

The polymer Q degree of the above-mentioned spinning stock solution is closely related to the polymerization degree from the viewpoint of the viscosity of the spinning stock solution, but in consideration of spinning stability, it is 13% by weight to 24% by weight, preferably 15% by weight to 22% by weight. % by weight.

As a manufacturing example of the fiber of the present invention, polyvinyl alcohol fiber will be described below.

A polyvinyl alcohol fiber with significantly higher strength and modulus of elasticity than conventional general-purpose vinylon fibers was published in Japanese Patent Application Laid-open No. 60-12.
It is known from the publication No. 6312. According to this publication, a polymer having a relatively high degree of polymerization is dissolved in a solvent (dimethyl sulfoxide (D)fsO), spun in a coagulation bath containing methanol as a main component, and then stretched approximately 20 times or more to obtain high strength. It is described that the fibers have a weight of 1q, and the tensile strength and tensile modulus of these fibers are certainly significantly higher than those of general-purpose nylon fibers, polyester fibers, vinylon fibers, etc. However, there is no disclosure of the bending abrasion characteristics of the fibers or any means for improving them.

In order to improve bending abrasion resistance while maintaining high strength and modulus of elasticity, the fiber of the present invention specifies the relationship between the degree of polymerization of the polymer used and the concentration of the spinning stock solution, thereby achieving The intended purpose of the present invention was achieved without drawing at a high magnification exceeding 1.

That is, the relationship between the degree of polymerization of the polymer and the temperature of the spinning dope in the present invention is as shown by the shaded area in FIG. 2 to 24% by weight) and then formed into a dense coagulated thread, which is then drawn at a relatively low magnification of about 14 to 20 times.

The manufacturing method of the present invention differs greatly from that of JP-A-60-126312 in the degree of polymerization of the polymer and the concentration range of the spinning dope. That is, a polymer having a higher degree of polymerization is wet-dry spun at a higher stock solution concentration.

According to the method disclosed in this publication, the viscosity of the spinning dope becomes extremely high in this concentration range, and stable spinning cannot be performed. In addition, in order to lower the viscosity of the spinning dope, the temperature of the spinning dope is raised (for example, 90° C. or higher), but since the solvent DMSO is relatively strongly alkaline (for example, E)H=12), the polymer deteriorates with this DMSO.

A decrease in molecular strength occurs, and the quality of the fiber obtained by spinning becomes significantly inferior. Therefore, acid is added to increase the p.p. of the spinning stock solution.
When H was adjusted to be in the range of about 5 to 10 and then subjected to spinning, it was found that spinning could be performed without causing a decrease in molecular weight. With this invention, for the first time, it has become possible to stably spin a spinning stock solution with a high polymer concentration exceeding the range described in the above publication, and the resulting fibers are of high quality and have excellent bending abrasion strength.

If the relationship between the degree of polymerization of the polymer and the concentration of the spinning dope is outside the range shown by the shaded area in Figure 1, it may be substantially difficult to form fibers, or even if fibers exhibit high strength and high modulus of elasticity cannot be obtained. However, the bending abrasion resistance is insufficient, and the filaments that make up the yarn in rope yarn knitted fabrics are damaged by rubbing against each other, making it difficult to use ropes and knitted fabrics that are highly durable for their intended purpose. I can't get it.

It should be noted that all other than the above-mentioned yarn spinning conditions may be in accordance with known yarn spinning conditions.

Thus, the melting point is 160°C or higher and the tensile strength is 1597d.
As described above, a polyvinyl alcohol fiber having a tensile modulus of 300 a/d or more and a bending abrasion strength of 2000 or more, which is particularly excellent in abrasion resistance compared to conventional fibers, can be obtained.

The melting point, tensile strength, tensile modulus, and bending abrasion strength here were measured according to the following measurement method.

(1) Melting point measured using a differential scanning calorimeter (OSC) at a heating rate of 10°C/min. The temperature at which the melting curve peaks is defined as the melting point.

(2) Tensile strength, tensile modulus Measured by a method according to ASTM D3379.

The sample fiber (multifilament yarn) was left for 48 hours in an atmosphere with a temperature of 20°C and a relative humidity of 65%.
It was adjusted.

A single filament constituting the prepared sample fiber is taken out and attached to a mount so that the gauge length is 2Qll1m. The tensile speed was 10 mm/min, and the strength was calculated from the average strength of 30 samples.

Furthermore, the tensile modulus is assumed to have been corrected for system compliance.

(3) Bending abrasion strength Using the measuring device shown in Figure 2, two filaments 1.
2 are crossed in a loop shape and attached to the clamp 3 and bars 4 and 4 degrees of the measuring device so that the crossing angle α is 60 degrees.

A load 5 of 200 ma per filament denier is suspended from the other end of the filament 1 attached to the clamp 3 (6
is a pulley).

6 per minute of filament 2 attached to bar 4, 4°
The filament is reciprocated at a speed of 0 rotations, and the number of reciprocations until the filament breaks is determined as the bending abrasion strength.

Note that the sample adjustment method is the same as in the above section (2).

[Effects of the Invention] The fiber of the present invention has high strength and high modulus of elasticity, and has excellent bending abrasion resistance, and can be used for ropes, hoses, seat belts, sewing threads,
The biggest advantage of the present invention is that it can be used as industrial materials such as fishing nets, or as marine materials, to make the product highly strong, or to make it thinner or thinner by taking advantage of its high strength (reducing the amount used). One of its characteristics is that it can greatly improve durability against loads such as bending, compression, and friction.

Hereinafter, the effects of the present invention will be specifically explained using examples.

Example 1 Degree of polymerization: 2600. Complete raw polyvinyl alcohol with a melting point of 226° C. was dissolved in DMSO to prepare spinning stock solutions with concentrations of 18% and 20%. The pI-1 of the spinning dope is p
-Toluenesulfonic acid was added to adjust the pH to 6.8.

These spinning stock solutions were subjected to dry-wet spinning at a spinning temperature of 100° C. in a coagulation bath solution consisting of methanol containing 10% DMSO.

The length of the space under the spinneret in wet-dry spinning is 7 m.
It was set as m.

The obtained undrawn yarn was washed with methanol to remove DMSO, and then hot-stretched in heated air at 230°C to obtain a drawn fiber (fineness: 2.5 d) with a draw ratio of 19.5 times.

For comparison, the same dry-wet spinning and hot stretching as above were performed for spinning stock solutions with polymer concentrations of 16% and 25% (fineness: 2.5 d).

The physical properties of the obtained fibers (filaments) are shown in Table 1. Moreover, the melting point of the fiber was 238-240°C.

(Hereinafter, blank spaces) Table 1*; Comparative Example Comparative Example 1 The same polymer as in Example 1 was dissolved in water as a solvent to prepare a spinning stock solution with a polymer concentration of 18%. This was wet-spun using a saturated aqueous solution of sodium sulfate as a coagulation bath.

The obtained undrawn yarn was subjected to moist heat stretching to 4 times, and after drying,
It was further stretched 3.5 times in heated air at 230°C.

The physical properties of the obtained fiber 111 (filament) are as follows: strength: 10
, 3a/d, elastic modulus of 164a/d, and bending abrasion strength of 780.

Example 2 Completely saponified polyvinyl alcohol with a degree of polymerization of 3500 and a melting point of 228° C. was dissolved in DMSO to prepare spinning stock solutions with concentrations of 15% and 17%. The pH of the spinning dope was adjusted to 1f=6.5 by adding p-toluenesulfonic acid.

These spinning stock solutions were mixed with DMSO at a spinning temperature of 110°C.
Wet-dry spinning was carried out in a coagulation bath solution containing 7% methanol. The length of the space under the spinneret in wet-dry spinning was 5 mm.

The obtained undrawn yarn was washed with methanol to remove DMSO, and then stretched 4 times in a methanol bath and dried. Subsequently, the film was stretched 4.9 times in heated air at 240°C (total stretching ratio: 19.6 times).

For comparison, dry-wet spinning and stretching were performed in the same manner as above for spinning stock solutions with polymer concentrations of 13% and 25%. However, when the polymer concentration was 25@R%, stable spinning could not be achieved.

The physical properties of the obtained fibers (filaments) are shown in Table 2.

Table 2: Comparative Example Example 3 A spinning dope having a concentration of 16% was prepared by dissolving completely carbon-based polyvinyl alcohol having a degree of polymerization of 5500 and a melting point of 232°C in DMSO. These spinning stock solutions were subjected to dry-wet spinning, stretching in a methanol bath, and stretching in heated air in the same manner as in Example 2 (total stretching ratio: 18.5 times).

For comparison, the polymerization degree was 12% and 20%.
The spinning dope was subjected to dry-wet spinning and stretching in the same manner as described above. When the polymer concentration was 20% by weight, the viscosity of the spinning dope was extremely high and spinning was unstable.

Table 3 shows the physical properties of the obtained fibers (filaments).

(Hereinafter, blank spaces) Table 3 Book: Comparative Example Comparative Example 2 In order to determine the performance of the fiber of the present invention, Table 4 summarizes the results of comparison with the performance of various commercially available high-strength fibers.

(Hereafter, margin)

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the relationship between the degree of polymerization and polymer concentration in a spinning dope for polyvinyl alcohol fibers according to the present invention, and FIG. 2 is a schematic diagram of a measuring device for bending abrasion strength according to the present invention.

Claims (2)

[Claims] (1) has a melting point of 160°C or higher, a tensile strength of 15 g/d or higher, and a tensile modulus of 300 g/d or higher;
An organic high-strength fiber with excellent abrasion resistance comprising filaments having a bending abrasion strength of 2000 or more. (2) The organic high-strength fiber with excellent abrasion resistance according to claim (1), wherein the polymer constituting the fiber is substantially polyvinyl alcohol.