JPS6052614A - Production of electrically conductive polyethylene fiber - Google Patents

Abstract

PURPOSE:To obtain the titled fibers having a low resistivity (tens of OMEGA.cm) and improved mechanical strength, by incorporating a linear low-density polyethylene resin having a specific melt index with a specific amount of electrically conductive fine powder, and drawing the resultant fibers at a low draw ratio. CONSTITUTION:A linear low-density polyethylene resin having 0.3-5.0 melt index and 0.91-0.95g/cm<3> density is incorporated with electrically conductive fine powder, e.g. carbon black, and the resultant mixture is then melted under heating, extrusion molded, cooled in water, etc., solidified and then drawn at 2- 5 times draw ratio to give the aimed fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for producing conductive polyethylene fibers.

(Prior art) Conventionally, as a method for manufacturing conductive polyethylene fibers, for example, a predetermined amount of conductive powder such as carbon black is mixed into powder or pellets of high-density polyethylene resin, and the mixture is melted using an extruder or the like and then passed through a nozzle. There is a method in which after extrusion, the material is cooled and solidified, then further stretched at a predetermined stretching ratio and wound up.

However, since the high-density polyethylene resin used in this manufacturing method has a linear molecular structure as shown in Figure 1, the minimum stretching ratio to obtain a uniform stretching state in the stretching process is 6 times. It is necessary to set it to a higher value. When the fibers are stretched at such a high stretching ratio, the conductive powder within the fibers is disconnected,
This leads to a decrease in conductivity and only a resistivity of 10 5 to IC Ω·cm can be obtained.

If the stretching ratio is set low in order to avoid this, the mechanical strength of the fiber itself may drop significantly and the fiber may become useless as a fiber. Also, in order to compensate for the decrease in conductivity, it may be possible to increase the amount of conductive powder mixed into the high-density polyethylene resin, but even if this amount is increased, the degree of bonding of the resin will become weaker and the fibers will become weaker. The mechanical strength of the material is significantly reduced.

Furthermore, it is also possible to use low-density polyethylene resin instead of high-density polyethylene resin, but this low-density polyethylene resin has a molecular structure with many long chain branches as shown in Figure 2, so it is difficult to stretch. It's impossible and la
It is inappropriate for maintenance.

(Name of the Invention) This invention has been made in view of the above points, and its purpose is to create an electrically conductive material that has a low resistivity of about several tens of Ωcm and has sufficient mechanical strength as a fiber. An object of the present invention is to provide a manufacturing method for obtaining polyethylene m-fiber.

(Structure of the Invention) In order to achieve the above objects, the present invention has a melt index of 0.3 to 5.0 and a density of 0.91 to 0.85 g/
10-35 cm for linear low-density polyethylene resin
It is made by mixing % by weight of conductive powder and stretching at a stretching ratio of 2 to 5 times.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

Now, in this embodiment, a linear low-density polyethylene resin is used in place of the high-density polyethylene resin in the conventional method described above. This linear low-density polyethylene resin has a molecular structure that is linear and has many short branches, as shown in FIG. Therefore, the minimum stretching ratio of this resin is 2 to 5 times, which is very low compared to 6 times or more for the above-mentioned high-density polyethylene resin, and if it is stretched at this stretching ratio, fibers with sufficient mechanical strength can be obtained. It is something that can be done.

And in this linear low density polyethylene resin,
In particular, the melt index is 0.3 to 5.0 and the density is 0.
A resin within the range of 91 to 95 g/crn" is used. If the melt index value is smaller than the same range, thread breakage is likely to occur and spinning becomes difficult.
Moreover, if it exceeds the same range, the viscosity becomes too high and spinning becomes difficult, so it is necessary to set it appropriately within this range.

An example of a method for producing conductive polyethylene #Il fibers using this linear low-density polyethylene resin will be described with reference to FIG. 4.

In this example, first, in the kneading step (1), 10 to 35% by weight of carbon black powder is mixed into the resin powder or pellets, and the mixture is kneaded, and in the pelletizing step (2), the resin is pelletized. Ru. here,
If the mixing ratio of the carbon black powder is too small, the conductivity will deteriorate, and if it is too large, the fiber strength will decrease, so it is desirable to set it within the above range.

The pellets thus produced are heated and melted in a heating step (3), extruded from a nozzle in an extrusion step (4), and then cooled and solidified in water or the like in a cooling step (5). After that, this solidified lol! In the drawing step (8), the U fiber is heated and drawn at a draw ratio of 2 to 5 times, and then
In the ring process (7), it is heat-shrinked with clean water to remove distortion, etc., and then wound in the winding process (8) to a fineness of 500.
Make fibers of ~3000 d.

As described above, in this example, a linear low density polyethylene resin with a low minimum draw ratio is used, this resin and carbon black powder are kneaded, and after heating, extrusion and cooling, Since it is drawn at a low draw ratio of 2 to 5 times, it is possible to produce conductive polyethylene fibers that have a low resistivity of about several tens of Ω/cm and also have sufficient mechanical strength as m-fibers. . By the way, the melt index is 0.64 and the density is 0.917g.
/ cm' linear low-density polyethylene resin mixed with 28% by weight of carbon black powder with an average particle size of 0.3 microns and stretched at a stretching ratio of 4 times, the fineness was 207.
1d, strength 1.12g/d, resistance 145Ω/10
cm of conductive polyethylene fibers could be obtained.

The fibers made in this way are then used as a heating element for carpets, blankets, etc., as shown in FIG.
2) is incorporated and used. In this heating element, when a voltage of about 50V was applied between a pair of conductive wires (13) provided at both ends, electric heat of about 20W could be obtained.

(Effect of the invention) As detailed above, the present invention has a melt index of 0.
．． 3-5.0, density 0.91-0.95g/c
10 to 35% by weight of conductive powder is mixed into the linear low-density polyethylene resin of M' and stretched at a stretching ratio of 2 to 5 times, so it has a low resistivity of about several tens of Ωcm. Moreover, it has the excellent effect of being able to obtain conductive polyethylene m fibers having sufficient mechanical strength as fibers.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the molecular structure of high-density polyethylene resin, Figure 2 is a diagram showing the molecular structure of low-density polyethylene resin, and Figure 3 is a diagram showing the molecular structure of linear low-density polyethylene resin used in this invention. 4 is a flowchart of a manufacturing process showing an embodiment of the present invention, and FIG. 5 is a schematic diagram showing an example of the use of conductive polyethylene fibers. 1: Kneading process, 4: Extrusion process, 6: Stretching process, 8: Winding process. Patent applicant Thailand 17 Co., Ltd.

Claims (1)

[Claims] Melt index 0.3-5.0, density 0.91-0
゜95g/crn' of linear low density polyethylene resin was mixed with 10 to 35% by weight of conductive powder, and the stretching ratio was 2.
A method for producing conductive polyethylene fiber, characterized by stretching the fiber by a factor of ~5.