JPS6017116A - Polyamide fiber having coarse surface and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the production of synthetic fibers by melt spinning blends of fiber-forming polyamides and immiscible polymers.

Recently, literature has appeared regarding the production of melt-spun polyamide fibers from fiber-forming polyamides to which other polymers have been added prior to melt-spinning.

JP-A No. 56-85420 (Teijin Ltd.) has a polymerization degree of 2.
The present invention relates to the production of unoriented polyamide yarn containing 0 or more polycarbonates of the bisphenol type in an amount between 0.5 and 10 parts by weight.

U.S. Pat. No. 3,475,898 discloses blends of polyethylene glycol and polyamide that are melt spun to form antistatic filaments. From the draw ratios shown in that example, it can be inferred that the winding speed of the spun filaments was substantially less than 1 km/min.

In European Patent Application No. 82305737.7, the inventors have disclosed that prior to melt spinning, a fiber-forming thermoplastic polymer is injected with 0.1 and 10 weights of other polymers which are immiscible in the melt of the polymer. A method has been described for melt spinning the thermoplastic polymer added in interweight amounts at a minimum take-up speed of 1 km/min.

In this method, the other polymer has an average particle size of between 0.5 and 6 microns in the fiber-forming polymer melt just before spinning. Example 4 of this European patent application relates to the production of fibers formed from a blend of hexaweight polyethylene and nylon 66. In this example, the fabric produced is characterized in that the fiber has a rough surface due to the depressions formed on its surface.

The present inventors have developed a fiber-forming polyamide that is immiscible with the melt of the polyamide and has a melt viscosity lower than that of the polyamide at the melt spinning temperature.
The novel rough surface polyamide yarn is produced by melt spinning a blend formed from a 45 weight plate or less with other polymers at a take-up speed of at least 2 km/min. It was discovered that it can be manufactured.

By "immiscible polymer" is meant that at the spinning temperature such polymer forms a two-phase melt with the fiber-forming thermoplastic polymer. When such melts are examined microscopically and optically photographed, biphasic melts show that the immiscible polymers form a circular shape (
This shows that it is a two-phase system in which the particles are dispersed (indicating that they are spherical particles).

However, this term "immiscible polymer" does not include liquid crystal polymers; that is, the additive polymer used in the present invention is anisotropic in the temperature range that allows thermoplastic polymers to be melt-spun. It does not form a melt.

This anisotropic state can be created when the liquid crystal polymer is heated or by applying shear to the polymer, but in the latter case the state must be maintained for several seconds.

The inventor has stated that the blend can include other polymers in as much as 45% by weight, but the actual proportions of other polymers that can be used in a particular polymer combination may vary depending on the phase inversion. It depends, but that transmission will not come. That is, in the present invention, it is not intended that a small proportion of the components by weight in the blend become a continuous phase, and the major components by weight are dispersed therein as a discontinuous phase.

The inventor has mentioned above that other polymers in the blend have a melt viscosity lower than that of the fiber-forming polyamide, which means that the other polymer has a melt viscosity of less than 25 parts of the melt viscosity of the polyamide at the spinning temperature. This means that it has a melt viscosity.

According to the invention, therefore, there is also provided a melt-spun fiber comprising at least 10 weight classes of other polymers as defined above, comprising:
Melt-spun fibers with rough surfaces are provided of fiber-forming polyamides in which the containing polymer is present in the fibers as microfibrils.

These microfibrils are very large, eg, typically have an aspect ratio, or length/diameter ratio, of 50 or more, and such microfibrils have a diameter of about 0.5 microns.

The method of the present invention applies to the more common fiber-forming polyamides,
For example, it is compatible with melt spinning of nylon 66 and nylon 6. However, this method is particularly suited for melt spinning nylon 66.

Suitable immiscible polymers are polyolefins such as polyethylene and polypropylene, and polyethylene glycols.

A feature of the method of the invention is that fibers with a novel rough surface are thereby produced.

Polyamide fibers produced by melt-spinning extrusion through small orifices usually have a smooth, shiny surface. Although the cross-section of filamentary fibers may be other than circular.

Fabrics made from such fibers have a slimy feel and are cool to the touch. Furthermore, when these fibers are made into staple fibers, the smooth feather surface makes it more difficult to process the stable fibers into yarn. The desired fiber enveloping force cannot be obtained either. Natural fibers such as wool and cotton have rough surfaces and tend to entangle in yarn. The rough surface also provides better thermal insulation and gives a warm feel to fabrics made from such spun yarns.

For this purpose, either finely divided photonic agents such as Merck, metal whiskers, alumina or silica carbide; or blowing agents are incorporated into the fiber-forming polymer before spinning, or the fibers are rapidly cooled with water or a solvent. Attempts have been made to obtain synthetic fibers with rough surfaces.

The method of the present invention provides polyamide fibers having a rough surface without using the methods described above.

For example, partially oriented fibers of the invention melt-spun at take-up speeds between 2 and 5 km/min are desirably subjected to a draw-texturing process. . Fibers produced by such a draw-texturing method retain a rough surface, but differ in details from fibers produced according to the method of the present invention. For example, more fully oriented fibers of the present invention melt-spun at take-up speeds of 5 kilometers per minute or higher can be used without further processing.

The invention will now be described with reference to the following examples. In these examples, the additive polymer is an immiscible polymer and forms a two-phase melt with the fiber-forming polymer.

Example 1 Industrial grade polyethylene-Alkatlene Grade as additive polymer
The polymer had a melt flow index of 200 and a melt viscosity of 12 Ns/yr+j at 10'N/rrl and 180°C.

The polyamide is industrial grade nylon 66 - Imperial Chemical Industries PLO Grade 5GS.
(Imperial Chemical Industry
ries PLC grade 5GS)-. The viscosity of this nylon was 8 ONS/'M2 at 104 N/nN and 285°C. Polyethylene of 10% by weight was mixed with nylon 66 as a chip blend, and the temperature was 290°C and the output rate was 110% using a laboratory melt spinning machine.
F/waiting time/holes The fibers were spun through 9 thousand spinning holes. No quenching or conditioner was used. The yarn was 2000-600'b. Scanning electron micrographs of the surface of the fiber spun at 3000 m/min showed that the surface was very rough and covered with bumps several microns in size. 60
Fibers spun at 00 m10 also have a rough, irregular surface, with a length of approximately 5μ9 and a width of approximately 0.5μ aligned along the fiber axis.
It was covered with μ fissures. Photographs of this spun fiber are shown in Figure 1 (600x magnification) and Figure 2 (
(Magnification: 3,000x). In contrast, 100% nylon 6 spun at the above winding speed under the same spinning conditions
6 fibers were perfectly smooth and cylindrical.

This spun yarn did not fall off the bobbin at any winding speed, even without a conditioner.

Scragg DC is a polyethylene blend yarn spun at 3000 m/min.
Stretch texture processing was performed using an 81,000 machine. Stretching ratio: 1.
65, stretching speed 40rrL/min, temperature of -next heater 1
The temperature was 90°C and the length of the heater was 5 m. The surface of this textured fiber is still rough and has a length of about 5-10μ, axially 0, which is at a small angle to the fiber axis due to the blending that occurred during draw texturing.
．． It had 5 micron cracks and in addition other scaly surface textures several microns in size. A photograph (000 magnification) of this textured fiber is shown in FIG.

Example 2 Melt flow index 2 as additive polymer
EXAMPLE 42 of specially prepared gray low viscosity propylene was mixed with nylon 66 as a chip blend and spun on a laboratory melt spinning machine under the same spinning conditions as in Example 1. The yarn was wound at 1,000 to 6,000 mm.

Scanning electron micrographs of the surface of the fiber spun at 3000 m15+ showed that the surface was very rough and had a similar appearance to the spun fiber of Example 1. This spun yarn did not fall off the bobbin at any speed, even without the use of conditioner.

[Brief explanation of the drawing]

Figure 1 shows polyethylene-containing nylon 66 fiber at a magnification of 60.
Figure 2 is an electron micrograph at 5000x magnification of a polyethylene-containing nylon 66 fiber, and Figure 3 is an electron micrograph at 3000x magnification of a textured polyethylene-containing nylon 66 fiber. It's a photo.

Claims (1)

Scope of Claims: (1) A melt containing at least 10 weight percent of another polymer that is immiscible with the melt of the fiber-forming polyamide and has a melt viscosity lower than that of the fiber-forming polyamide at the melt spinning temperature. 1. A melt-spun fiber having a rough surface and made of a fiber-forming polyamide, characterized in that the polymer contained therein exists as microfibrils in the fiber. Claim (1) wherein the other immiscible polymer is either polyethylene or polypropylene.
A melt-spun fiber having a rough surface made of the fiber-shaped polyamide according to 1. (3) a fiber-forming polyamide that is immiscible with the melt of the fiber-forming polyamide and has a melt viscosity lower than that of the fiber-forming polyamide at the melt spinning temperature; 1. A method for producing a polyamide yarn, characterized in that a blend formed from the following polymers is melt-spun at a minimum winding speed of 2 km/min. (4) Claim 3, wherein the other immiscible polymer is either polyethylene or polypropylene.
) Method described in section.