KR100959867B1 - Method for producing ultra high strength polyethylene fiber and ultra high strength polyethylene fiber produced therefrom - Google Patents

Abstract

The present invention relates to a method for preparing an ultra high strength polyethylene fiber and to an ultra high strength polyethylene fiber prepared therefrom, wherein the method for preparing an ultra high strength polyethylene fiber is obtained by mixing polyethylene having a weight average molecular weight of 200,000 to 5 million with a first solvent of a nonvolatile organic compound. Forming a gel solution having an inherent viscosity of 23 dl / g; Spinning the gel solution with a die to form gel fibers; Immersing and cooling the gel fibers in a second solvent of a liquid volatile organic compound having a high temperature near a volatilization point; And extracting the first solvent by jet spraying a second solvent of a gaseous volatile organic compound to the cooled gel fibers and simultaneously stretching the gel fibers in a draw ratio of 30: 1 to 50: 1.

According to the production method according to the present invention it is possible to produce an ultra-high strength polyethylene fiber having excellent chemical resistance with excellent mechanical properties such as high strength and high elongation.

Ultra High Strength Polyethylene, Strength, Elongation

Description

Manufacturing Method of Ultra High Strength Polyethylene Fiber and Ultra High Strength Polyethylene Fiber Manufactured Therefrom

The present invention relates to a method for producing an ultra high strength polyethylene fiber and to an ultra high strength polyethylene fiber prepared therefrom, and more particularly, to provide an ultra high strength polyethylene fiber having excellent chemical resistance along with excellent mechanical properties such as high strength and high elongation. The present invention relates to a method for producing an ultra high strength polyethylene fiber and an ultra high strength polyethylene fiber produced therefrom.

High-strength polyethylene fiber has been widely used in various fields in various fields due to its excellent mechanical properties such as high strength and high elongation and excellent chemical properties such as excellent chemical resistance.

As a method for producing such a high strength polyethylene fiber, there are an ultra-high stretching method, a solid state extrusion method, a band stretching method, a gel spinning method, etc. Among these, a gel spinning method capable of mass production is widely used.

In the gel spinning method, ultra-high molecular weight polyethylene is mixed with a nonvolatile first solvent to form a gel solution, gel fibers are formed through spinning in a cooling bath, and the nonvolatile first solvent is removed using a volatile second solvent. And stretching the gel fibers.

In this process, ultra-high molecular weight polyethylene is lined with thin fibers in a long line, and in order to break the fiber, it is necessary to break the linkage of many molecules very much and thus has high strength.

However, as a volatile solvent used in the related art, not only the non-volatile solvent dissolving high-strength polyethylene fibers can be completely extracted but also the separation of the volatile solvent and the non-volatile solvent is difficult and cannot be reused.

In addition, the fiber produced by the manufacturing method has a creep and stress inherently generated during the solidification and stretching process, causing a breakage due to cracks, and the first solvent is not completely removed In the state, it cannot have sufficient rigidity.

The present invention is to solve the above problems, by using ultra-high molecular weight polyethylene (UHMwPE -Ultra High Molecular Weight PE) of the molecular weight of several hundred thousand to millions of moles excellent mechanical properties and excellent resistance such as ultra high strength, high elongation An object of the present invention is to provide a method for producing an ultra high strength polyethylene fiber capable of producing a fiber having chemical properties and the like.

It is another object of the present invention to provide a method for producing ultra high strength polyethylene fiber which can remove creep and stress in the fiber while completely removing the nonvolatile first solvent.

The present invention also provides an ultra high strength polyethylene fiber produced by the above production method.

However, technical problems to be achieved by the present invention are not limited to the above-mentioned problems, and other technical problems will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention,

Mixing a weight average molecular weight of 200,000 to 5 million polyethylene with a first solvent of a nonvolatile organic compound to form a gel solution having an inherent viscosity of 17 to 23 dl / g;

Spinning the gel solution with a die to form gel fibers;

Immersing and cooling the gel fibers in a second solvent of a liquid volatile organic compound having a high temperature near a volatilization point; And

Jetting a second solvent of a gaseous volatile organic compound to the cooled gel fibers to extract the first solvent and stretching the gel fibers at a draw ratio of 30: 1 to 50: 1.

It provides a method for producing ultra high strength polyethylene fiber comprising a.

In another aspect, the present invention provides an ultra-high strength polyethylene fiber produced by the above production method.

Other specific details of embodiments of the present invention are included in the following detailed description.

As described above, according to the ultra-high strength polyethylene fiber manufacturing method of the present invention, it is possible to produce ultra-high strength polyethylene fiber having excellent mechanical resistance such as ultra high strength and high elongation and excellent chemical resistance. Such ultra high strength polyethylene fibers can be used in various applications in various fields such as body armor, safety gloves, medical, various ropes, helmets, ski boards.

In addition, according to the manufacturing method of the present invention, it is possible to completely remove the first solvent from the gel fiber and to remove creep and stress generation.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, whereby the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

Unless otherwise specified in the present specification, "ultra high molecular weight" means a weight average molecular weight of 200,000 or more, and "ultra high strength" means having an intensity of 30 g / d or more.

In addition, in this specification, "total draw ratio" means the value obtained by dividing the maximum roller speed by one stage high roller speed among rollers from single stage high roller to winding roller.

Ultra high strength polyethylene fiber manufacturing method according to an embodiment of the present invention

Mixing a weight average molecular weight of 200,000 to 5 million polyethylene with a first solvent of a nonvolatile organic compound to form a gel solution having an inherent viscosity of 17 to 23 dl / g (S1);

Spinning the gel solution with a die to form gel fibers (S2);

Immersing and cooling the gel fiber in a second solvent of a high temperature liquid volatile organic compound near a volatilization point (S3); And

Jet spraying a second solvent of a gaseous volatile organic compound on the cooled gel fibers to extract the first solvent and stretching the gel fibers at a draw ratio of 30: 1 to 50: 1 (S4)

It provides an ultra-high strength polyethylene fiber manufacturing method comprising a.

Hereinafter, the ultra high strength polyethylene fiber manufacturing method of the present invention will be described in more detail in each step.

(S1) gel solution forming step

First, the ultrahigh molecular weight polyethylene is dissolved using a nonvolatile organic compound first solvent to form a gel solution (S1).

The ultra-high molecular weight polyethylene is a polyethylene homopolymer having only repeating units made of ethylene, or the repeating unit consists essentially of ethylene, and air copolymerized with 5 mol% or less of other monomers copolymerizable with ethylene such as alkene. It is a copolymer.

The ultra high molecular weight polyethylene has a weight average molecular weight of 200,000 or more, and preferably has a weight average molecular weight of 200,000 to 5 million. If the weight average molecular weight is out of the range is too small, the number of end groups of the polymer chain is increased to act as a weak part in the final polyethylene fiber is difficult to obtain high strength properties. Therefore, it is preferable to use polyethylene having a weight average molecular weight within the above range.

In addition, the polyethylene preferably has a ratio (Mw / Mn ratio) of the number average molecular weight to the weight average molecular weight of 10 or less, and more preferably 5 to 8 Mw / Mn ratio. When having a narrow molecular weight distribution as described above it can be produced a polyethylene fiber having superior strength characteristics.

As the first solvent, a nonvolatile organic compound may be used. Preferably, a hydrocarbon-based organic compound having a boiling point of 350 ° C. or higher and more preferably 350 to 500 ° C. under atmospheric pressure is used. The first solvent having the above characteristics is excellent in solubility in ultra high molecular weight polyethylene, and can be easily extracted by the second solvent in the subsequent extraction process, and can be reused, and there is no fire risk, so it is excellent in handling. Do.

Specifically, the first solvent may be an aromatic hydrocarbon such as xylene, toluene, fluorene, or the like; Aromatic hydrocarbons such as trichlorobenzene; Decalin; Tetralin; Paraffin oil; Petroleum mineral oils; Mineral oils can be used.

In preparing the gel solution, the ultra high molecular weight polyethylene is preferably used in an amount of 5 to 20 parts by weight based on 100 parts by weight of the first solvent. If the content of ultra high molecular weight polyethylene is too low outside the above range, there is a fear that the strength characteristics such as strength, elongation, etc. of the final polyethylene fiber is lowered, and if the content of ultra high molecular weight polyethylene is too high, the solubility may be lowered. Not desirable Therefore, it is preferable to be used in the above content range in terms of the physical properties of the final prepared ultra-high strength polyethylene fibers and the solubility balance of the ultra high molecular weight polyethylene.

In addition, the ultra-high molecular weight polyethylene dissolution step is preferably carried out at 135 to 150 ℃. The solubility of ultra high molecular weight polyethylene in the first solvent is excellent when the dissolution process is carried out in the above temperature range.

It is preferable that the gel solution of ultra high molecular weight polyethylene prepared by the above method has an intrinsic viscosity of 17 to 23 dl / g. When it has intrinsic viscosity in the said range, since it has the outstanding crystallinity degree, extending | stretching is made smoothly and it is preferable because it can obtain the outstanding strength and elongation.

(S2) gel fiber forming step

Next, the prepared gel solution is spun with a die to form gel fibers (S2).

The gel fiber forming process may be carried out by spinning the prepared gel solution through a plurality of spinneret formed in the die through an extruder.

The spinning temperature at the time of spinning is preferably 120 ° C. or more, more preferably 120 to 210 ° C. The spinning pressure is preferably 5 kPa or less, more preferably 1.5 kPa or less. More specifically, it is preferable to maintain the temperature in an extruder at 160-180 degreeC, and it is preferable to maintain the temperature of the said dice | dies at 190 degreeC-210 degreeC.

In addition, the ratio of the length to the diameter (L / D ratio) of the die is preferably 25: 1 to 60: 1. When within the above range, the gel solution passing through the spinneret of the die can be maintained at an optimum intrinsic viscosity to produce polyethylene fibers having excellent strength and elongation.

(S3) immersion and cooling step of gel fibers

The gel fiber having passed through the spinneret of the die is immersed in the second solvent of the liquid volatile organic compound and cooled (S3).

The gel fiber passing through the spinneret passes through an air gap, which is a gap between the tip of the die and the surface of the second solvent, before being immersed in the second solvent. At this time, the length of the air gap is preferably 2 to 10mm. In addition, the air gap is preferably blown with an inert gas such as N ₂ to prevent air, more preferably oxidation, at a rate of 1 m / min.

As the second solvent, a volatile organic compound that is harmless to the human body can be used without changing the polyethylene gel structure, and preferably, a liquid volatile organic compound having a boiling point of 60 to 80 ° C. under atmospheric pressure is used. When having such a boiling point range, it can remain on the surface of the gel fiber for a desired time of operation without fear of premature evaporation, and then can also be easily removed without fear of remaining.

Specifically, alcohol, such as ethanol; Ethers such as diethyl ether and the like; Ketones such as acetone, cyclohexanone, 2-methylpentanone, and the like; Alkanes such as ethane and n-hexane; Haloalkanes such as dichloromethane and trichlorotrifluoroethane; And mixtures thereof.

When the gel fiber is cooled, the temperature of the second solvent is preferably high temperature close to the volatilization point, and more preferably, the volatilization point of the second solvent is performed at ± 10 ° C.

By immersing and cooling the gel fibers in the high temperature second solvent as described above, cooling can be slowly performed from the core portion to the outer portion of the gel fibers, and as a result, generation of stress and creep can be suppressed.

(S4) jet spraying and stretching step

Next, a jet of a second solvent of a gaseous volatile organic compound is jetted onto the cooled gel fibers to extract the first solvent and to stretch the gel fibers (S4).

The extraction process of the first solvent using the second solvent may be carried out by jet spraying the second solvent when the cooled gel fibers for the stretching process passes through the rollers.

As described above, by carrying out the stretching process simultaneously with the extraction process of the first solvent by jet injection, the intrinsic stress and creep can be removed to improve the uniformity, and also the trimming can be generated during the stretching process, thereby improving workability. . In addition, the orientation of the fibers is directly related to the strength, and jet orientation may increase the orientation of the fibers.

The stretching process as described above is preferably drawn in a total draw ratio of 30: 1 to 50: 1, the stretching process may be carried out in one step, but at least two steps in order to prevent the trimming during stretching and to perform uniform stretching. It is preferable to carry out. More preferably, it is good to carry out in three or more steps.

For example, in the case where stretching is performed in three steps, a primary stretching step of stretching while jet-spraying a second solvent having a high temperature (volatile point of the second solvent + 50 to 80 ° C.) beyond the volatile point; A secondary stretching step of stretching while jet-spraying a second solvent having a medium temperature (volatile point of the second solvent + 20 to 50 ° C.) just above the volatile point with respect to the primary stretched fiber; And a third stretching step of stretching the secondary stretched fiber at a low temperature (volatile point of the second solvent + 5 to 20 ° C).

The primary stretching step is carried out by jet spraying a high temperature second solvent that exceeds a volatilization point of the second solvent when passing through the primary roller. Specifically, it is preferable that the temperature of the said 2nd solvent is 120-150 degreeC. The first solvent remaining in the stretched fiber in the above temperature range is preferably volatilized and at the same time prevents the fiber from rapidly cooling from the surface.

In this case, the injection speed of the second solvent is preferably 10 to 20 times faster than the stretching speed. If it is too fast beyond the stretching speed, the fiber may be damaged. If too slow, the annealing effect may occur only for a short distance. Not desirable

Moreover, it is preferable that the temperature of the said roller is very high temperature, specifically, 120-150 degreeC. At this time, the draw ratio is preferably 70% or more of the total draw ratio.

Subsequently, the secondary stretching is performed on the primary stretched gel fibers.

Secondary stretching may be carried out by jet-jetting a medium temperature second solvent just beyond the volatilization point of the second solvent when passing through the secondary roller. At this time, the injection speed of the second solvent is preferably 20 to 40 times faster than the spinning speed.

Moreover, it is preferable that the temperature of the said roller is medium temperature, specifically, 100-130 degreeC. At this time, the draw ratio is preferably 20% or less of the total draw ratio.

Tertiary stretching is then effected by passing a tertiary roller (roller temperature low temperature) through the secondary stretched gel fibers without jet spraying.

The temperature of the roller at the time of tertiary stretching is low temperature, specifically, it is preferable that it is 80-120 degreeC.

Optionally, the process of connecting the ethylene molecules broken by the last annealing may be further carried out by spraying a high temperature second solvent beyond the volatilization point to the fiber at a rate of 5 to 10 times.

The ultra high strength polyethylene fiber produced by the above manufacturing method has excellent mechanical properties such as excellent strength and elongation as well as excellent chemical resistance. Specifically, it has a strength of 30 g / d or more and a high elongation of 3% or more.

Accordingly, according to another embodiment of the present invention provides an ultra-high strength polyethylene fiber produced by the manufacturing method. The ultra high strength polyethylene fiber has excellent mechanical properties and chemical resistance, and can be used in various fields such as cables, canvas, body armor, safety gloves, medical, various ropes, helmets, ski boards, sports and automobile equipment, and building materials. have.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

<Example 1>

Ultra high molecular weight polyethylene (weight average molecular weight: 2 million, molecular weight distribution (Mw / Mn ratio) = 5) slurry containing a mixture of 95% by weight and 5% by weight of hydrocarbon paraffin oil having a boiling point of 350 ℃ as the first solvent The mixture was added to a stirrer holding a temperature atmosphere of 140 ° C. to form a gel solution having an intrinsic viscosity of 20 dl / g.

The formed gel solution was spun through a spinneret of a die having an L / D ratio of 25: 1 using an extruder of 170 ± 10 ° C., precipitated in a second solvent of trichlorotrifluoroethane at 70 ± 10 ° C., and cooled to a gel. Fibers were formed. At this time, the air gap, which is the distance between the die and the second solvent, was set to 3 mm, and N ₂ gas was blown in.

Subsequently, the second solvent of trichlorotrifluoroethane at 150 ° C. was jet sprayed 10 times faster than the drawing speed while passing through the roller at 135 ° C. to primary cooling at a draw ratio of 70%.

The second solvent of 120 ° C. trichlorotrifluoroethane was jet sprayed 20 times faster than the drawing speed while passing through the roller at 115 ° C. for the first drawn fiber, and the second drawing was performed at a draw ratio of 20%. The third stretching was carried out through a roller at 80 ° C. without.

Ultra high strength polyethylene fibers were prepared by spraying trichlorotrifluoroethane at 90 ° C. at a rate of 5 times with respect to polyethylene fibers drawn at a total draw ratio of 30: 1 through three-step stretching.

<Example 2>

The ultra-high strength polyethylene fibers were prepared in the same manner as in Example 1 except that the draw was performed at a total draw ratio of 40: 1 through three-stage stretching.

<Example 3>

The ultra-high strength polyethylene fibers were prepared in the same manner as in Example 1 except that the draw was performed at a total draw ratio of 50: 1 through three-stage stretching.

The strength and elongation of the polyethylene fiber prepared in Example 1 were measured by the following method.

Tensile properties were measured using an Instron material tester at a tensile rate of 300 mm / min, a sample length of 250 mm, and an atmosphere of 20 ° C. × 65% RH. Denier krill was used to measure the denier of the sample and applied to the strength calculation. .

As a result of the measurement, the polyethylene fibers produced according to Examples 1 to 3 all exhibited strengths of 30 g / d or more and high elongation of 3% or more.

The present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is possible.

Claims (5)

Mixing a weight average molecular weight of 200,000 to 5 million polyethylene with a first solvent of a nonvolatile organic compound to form a gel solution having an inherent viscosity of 17 to 23 dl / g; Spinning the gel solution with a die to form gel fibers; Immersing and cooling the gel fibers in a second solvent of a liquid volatile organic compound having a high temperature near a volatilization point; And Extracting the first solvent by jet-jetting a second solvent of a gaseous volatile organic compound to the cooled gel fibers, and simultaneously stretching the gel fibers at a draw ratio of 30: 1 to 50: 1. The stretching step A primary stretching step of stretching the second solvent having a high volatile point over 50 to 80 ° C. while jet spraying at a speed of 10 to 20 times faster than the stretching speed; A secondary stretching step of stretching while jet-spraying a second solvent having a medium temperature exceeding a volatile point of 20 to 50 ° C with respect to the primary stretched fiber; And Method for producing a very high strength polyethylene fiber comprising a tertiary stretching step of stretching at a low temperature of more than 5 to 20 ℃ volatilization point for the secondary stretched fiber. The method of claim 1, Wherein the first solvent is a hydrocarbon solvent having a boiling point of 350 ℃ or more under atmospheric pressure ultra high strength polyethylene fiber manufacturing method. The method of claim 1, The second solvent is a liquid volatile organic compound having a boiling point of 60 to 80 ℃ under atmospheric pressure manufacturing method of ultra high strength polyethylene fiber. delete Ultra-high strength polyethylene fibers having a strength of at least 30 g / d and a high elongation of at least 3%, produced by the manufacturing method according to any one of claims 1 to 3.