JPS60185812A - Production of polyethylene fiber - Google Patents

Abstract

PURPOSE:A polyethylene solution is extruded out and a plurality of the resultant gel filaments are taken up under heat melting to enable easy production of polyethylene fibers of high thickness, high strength and high elasticity. CONSTITUTION:A polyethylene solution is extruded and at least 2 of the resultant gel filaments are collected and taken up as they are fused under heating to give the objective fiber. In the fusion of the gel filaments, these filaments are passed through a die which has a narrower cross section than the total cross section of the filaments B as well as the inlet of a conical shape A. Further, the molecular weight of the polyethylene used is preferably more than 200,000.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyethylene fibers, and more specifically to a method for producing high strength, high modulus, and thick gIL fibers by spinning a polyethylene solution. be.

Conventional high strength, high modulus polyethylene fiber? In the method of fabrication E-, a gel-like fiber is produced by spinning a polyethylene solution with a large average amount of -f in L2 and cooling it. A method of further heating and stretching is known.

However, the problem with this method is that the final pL
Fibers such as thick fibers tend to have low tensile strength and modulus, and it has been difficult to obtain thick, high strength, and high modulus fibers.

Therefore, with this method, υ can be used as a tensile strength wire, for example, with a cross-sectional area of 0.01- or more, and with high strength.
It has also been extremely difficult to produce polyethylene fibers with a high elastic modulus.

The present invention provides a new improvement to such a method with a thicker cutting edge, high strength, and 2 high modulus. M of polyethylene fiber with
This made it possible to completely construct it.

The present inventors have paid special attention to the fact that the thicker the gel-like fibers spun from a solution, the more difficult it is to stretch them at a high magnification. As a result of our efforts, we have finally arrived at the present invention which solves the above-mentioned problems.

That is, according to the present invention, two or more gel-like fibers obtained by spinning a polyethylene solution are pulled together, heated, fused, and taken off. , le.

The polyethylene solution of the present invention preferably has an average molecular weight (
Viscosity method) is prepared by heating and dissolving polyethylene of 200,000 or more in the solvent. For the solvent and 12, decalin or fluidized ζ rough-in can be used.

In general, the higher the average molecular weight of polyethylene, the higher the strength.
High Moji, Russ? Is it suitable for obtaining high strength and high modulus fibers for less than 200,000 yen? It is difficult to obtain, and it becomes difficult to obtain.

For spinning, the polyethylene solution was heated to 1.2 mm (1.2 mm) and cooled to 1 mm containing the solvent.
(This is done by hitting.

In order to heat the gelled fibers vf-2 or more obtained in this way and heat them together, the required force'(j
710, f-, but during the fusion, the number of gel foreshadowing lines ta to be aligned is adjusted so that the thickness of the fiber after drawing becomes the thickness VC that suits the purpose of use. The thicker the fiber, the more difficult it is to stretch at a high magnification.
In order to obtain high modulus fibers, it is preferable that the original gel-like fibers be thinner.

However, the thinner the original gel-like fibers are, the greater the number of fibers that must be pulled to obtain the required thickness, which requires more equipment and time.L
Therefore, the practically preferable thickness of the gel-like fibers is determined by these considerations.

The fusion of the gel-like fibers arranged in the bow 1 is performed by heating 1. This is done by adding chips to the gel-like fibers that have been pulled out in order to bundle and integrate them.

Any method of applying force may be used as long as it is convenient for the fusion of the gel-like fibers, but in order to create well-fused fibers with a circular cross section, gel-like fibers should be Is the cross-sectional area smaller than the sum of its cross-sectional areas? A circular hole with? The method of passing all the motsu dai and taking it is @
suitable for

Of course, holes of arbitrary cross-sectional shape to create fibers of arbitrary cross-sectional shape? It is also possible to let it pass.

It is also possible to actively stretch the fibers during take-off by utilizing the resistance when the key money passes through.

The smaller the cross-sectional area of the pores is compared to the cross-sectional area of the gel-like fibers, the stronger the fusing force is, but it is limited to the extent that the pulling resistance increases and the fibers do not break.

If the hole [is provided with a conical introduction part, the purpose can be achieved more smoothly. FIG. 1 is a schematic diagram showing an example of a method for converging and integrating two or more gel-like fibers using a hole (die) having a conical introduction section.

There is also a method of adding chips to align the gel-like fibers so that they are bundled and integrated, and a method of running the fibers while pressing them between rollers. FIG. 2 is a schematic diagram showing an example of a method for converging and integrating gel-formed fibers while pressing between two or more rollers.

Heating during fusing facilitates fusing and is also advantageous for stretching. The heating temperature is preferably as high as possible within a range that does not reduce the strength and modulus of the drawn fibers.

If necessary, the fused fibers are further subjected to hot stretching to produce the desired polyethylene fiber.

As the stretching method, methods such as stretching in a heated air tank or liquid heat medium, dielectric heating stretching, and drawing stretching using a heating die can be used.

As a method for complete fusion, there is a method of combining two or more liquid fibers immediately after spinning but before solidifying, but there is no big difference between spinning one fiber corresponding to the combined thickness and the present invention. No such effect was observed.

Note that it is clear that it is difficult to obtain a high modulus even if a large number of fibers are arranged in the fused yarn +, which is incompletely fused.

As mentioned earlier, the conventional method of hot-drawing gel-like fibers obtained by solution spinning polyethylene is a high-strength, high-modulus fiber. Is thick fiber suitable for manufacturing? There is a problem in that the more one attempts to obtain a fiber, the lower the strength and elastic modulus of the fiber obtained, making it impossible to achieve the intended purpose.

The reason for this is that the spun gel fibers are contained in a large amount of the solution, making their cross-sectional area extremely large.
It is presumed that this is because the thicker the gel fiber is, the more likely it is that unevenness of the fiber in the cross-sectional direction of the fiber, ie, the difference between the inner and outer layers, and other unevenness will occur when the gel fiber is formed by spinning.

In the present invention, relatively thin gel-like fibers are spun and the i'L
It is possible to obtain all the drawn yarns of the required thickness by fusing all the yarns together.

The fusion effect differs from the known fused yarn in which only the surfaces of the fibers are fused together, and the effect of the fusion depends on the way the force is applied to fuse the fibers and the action of the solvent contained. The cross-sectional shape can be completely formed, and F+l') is accompanied by almost complete integration.

According to the present invention, is it thick and has high strength and high modulus? It is relatively easy to produce polyethylene fibers having the following properties.

For example, if the cross-sectional area of the monofilament is 0.01- or more, the tensile strength is t s o Kt/- or more, and the tensile modulus is 3.5.
Polyethylene fibers of 0.00 Kf/- or more can be produced more easily than with the prior art.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A solution consisting of 4% by weight of polyethylene having an average molecular weight (viscosity method) of 2 x 10' and 96% by weight of decalin was extruded through the holes of a spinneret. After cooling and solidifying 1. A gel-like fiber was prepared.

At that time, the temperature of the solution was 130 °C, and the cooling assimilation was 30 °C.
It was forced into the water.

The pore diameter of the spinneret was 0.7mm, the number of filaments in the gel-like fiber obtained was 180, and the cross-sectional area of each filament was 0.71mm on average in a state containing 94.5% by weight of decalin. Met.

All of this gel-like fiber was passed through a die having holes in the shape shown in FIG. 1, and drawn while being stretched to double its length.

At that time, the temperature in Thailand was maintained at 100°C.

Subsequently, the film was stretched 8.8 times through a heated air tank at 130°C, and then stretched 2x through a heated air tank at 140°C, resulting in a substantially decalinge-free stretching film with a total stretching ratio of 35x. Obtained fiber.

Stretching the line! ! During the manufacturing process, all the monofilaments that make up the original gel fiber are fused together.1. It had a completely single circular cross section, and its cross-sectional area was 0.205-.

The drawn fibers had a tensile strength of 301 KP/-, a tensile modulus of 8,400 KP/-, and exhibited sufficient bending resistance even at 1-.

Examples 2-4 Average molecular weight (viscosity method J2X1 (16 polyethylene 3.
A gel-like fiber was prepared by extruding a solution consisting of 5-nail abscess and 96.5% by weight of decalin through the holes of a spinneret, cooling and solidifying it.

At that time, the temperature of the solution was 130°C, and the cooling solidification was performed in water at 30°C. . Subsequently, gel-like fibers consisting of a large number of filaments were fused together and further drawn in the same manner as in Example 1.

The cross-sectional area of the hole in the die used for fusion corresponded to 70 to 90% of the cross-sectional area of the gel-like fibers.

The number of filaments of the gel-like fibers, the cross-sectional area of each filament of the gel-like fibers, the total stretching ratio, the cross-sectional area of the drawn nt#, the tensile strength, and the tensile modulus of the drawn fibers were as shown in Table 1.

Comparative Example Gel-like fibers were obtained by spinning in the same manner as in Examples 2 to 4, but in this case, the filaments of gel-like fibers were number 1, and their cross-sectional area was particularly large compared to other Examples. This gel-like fiber was similarly drawn, but the drawing ratio that was reasonably possible was lower than in the other examples, and both the tensile strength and tensile modulus of the drawn GL fiber were low.

Those values are shown in Table 1 as in Examples 2-4.

m1 table

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a method for converging and integrating two or more gel-like fibers using a hole having a conical introduction section. FIG. 2 is a schematic diagram showing an example of a method of converging and integrating two or more gel-like fibers while pressing them with an open roller. A. Shape the circle Φ and φ1. Grooved part B...Gel granulation l fiber D...0.Take-off direction d...Diameter of hole R1R'...Roller patent applicant Toyo Spinning Co., Ltd.

Claims (1)

[Claims] l. A method for producing polyethylene fibers, which comprises spinning a polyethylene solution completely, pulling two or more gel-like fibers together, heating them, fusing them together, and taking them off. The polyethylene according to claim 1, wherein the method of fusing and taking off the 22 ν fibers is a method of passing gel-like fiber gold and a key metal having a cross-sectional area smaller than the sum of the cross-sectional areas thereof and taking it off. Fiber manufacturing method.