KR930012186B1 - Sheath core fiber and its method of manufacture - Google Patents

Abstract

A sheath core fiber having an inner core (10) made from an oriented thermoplastic material, such as polyester, nylon, acrylic, and olefin, and a sheath (18) made of a nonthermoplastic material, such as regenerated cellulose and protein. The fiber maintains the crease and tear resistance of the core material, yet has the water sorptivity and dyeability of the sheath material. A method of manufacturing such a fiber is also disclosed.

Description

[Name of invention]

Sheath core fiber and manufacturing method thereof

[Brief Description of Drawings]

1 is a schematic view of the fiber production method of the present invention.

2 is a perspective view of a single fiber.

3 is a scanning electron micrograph (1250x ratio) of the fibers produced by the present invention.

Detailed description of the invention

[Background of invention]

There has been some recognition of the desire to combine the optimal characteristics of orienter thermoplastics, such as maintaining wrinkles and tear resistance, with the saltiness and sortivity of natural materials. Attempts in this direction usually ended with mixing the two materials together, so that the properties of the materials were averaged rather than each of the most desirable properties of the component being optimized.

)도중 휘발성 용매는 성형 레이온을 통해 확산되어, 채색물질만 남게 된다. 염료는 레이온을 향한 경사(gradient)를 만들기 때문에 내부의 심부는 분리된 별개의 지역으로 존재하지 않는다.Co-extrusion of the other two materials to make side-by-side bicomponent fibers has been extensively performed, primarily to develop corrugated products. For example, US Pat. No. 2,439,813 to Culpe describes such a product in which both components are viscose with different shrinkage due to different concentrations of cellulose, carbon disulfide or sodium hydroxide and different maturation times. In addition, sheaths were usually constructed for pleating purposes. Bragow, for example, US Pat. No. 3,458,615 describes co-extrusion of two streams in molten state and inducing orientation under the die. Bragow's patent relates to the production of light guides in which a well-regulated smooth interface is important for sustaining the internal reflection of light passing through the core and reflecting off the surface. Ditchi US Patent No. 2,932,079 discloses a sheath core structure that must contain at least two cores of different materials and a sheath of a third material. Thus, wrinkles can be made by the heat shrinkage difference between the non-concentric core and the outer layer. Vannermann's US Pat. No. 2,989,789 also relates to the production of sheath core fibers in which both layers are polyamide. Deep polyamides are selected or modified to provide better dye solubility. Meyer's US Pat. No. 2,063,180 discloses a coextrusion process in which an internal stream of volatile solvents with colored material passes through a wick and then is covered by a viscose solution. radiation(

In the process, the volatile solvent diffuses through the molded rayon, leaving only the colored material. Since the dye creates a gradient towards rayon, the inner core does not exist as a separate, separate area.

Overview of the Invention

The present invention relates to interior cores made of oriented thermoplastics and other oriented thermoplastics such as nylon, polyester, acrylics and olefins, and to sheaths made of non-thermoplastics such as rayon or regenerated proteins and other suitable non-thermoplastics. It relates to the calculation of the outer core fiber comprising a.

The present invention also relates to a process for producing such fibers in which the core fibers are drawn through a liquid sheath-forming material and drawn through a die. Since the core fibers are already oriented and also in solid form, there is a very low tensile load on the sheath material so it will not exhibit significant crystallographic orientation during the drawing process as it would be when drawn alone from the die. This produces a sheathing material that is not oriented and as a result has increased absorbency and saltability. However, because the core material accounts for most of the fiber cross section, the wrinkle, tear resistance and strength characteristic of the core material will be maintained. In producing such fibers, it is not necessary to solidify the sheath material immediately after it exits the die due to the tensile strength of the inner core structure present. The die front therefore does not have to come into contact with an acid bath as in the case of drawing viscose fibers from the die. This reduces the need to make the front of the die precious metal and significantly reduces and simplifies manufacturing costs.

It is therefore an object of the present invention to provide sheath core fibers that combine the most preferred features of the core with the most preferred features of the sheath.

The object of the invention also relates to a method of making such a product. These and other objects and advantages of the present invention will be apparent from the detailed description of the invention which follows.

Now, in the method of making the fibers of the present invention, with reference to the drawings, in particular FIG. 1, the core material 10 is introduced into a chamber 11 having a die 12 provided at its lower end. The liquid sheath-forming material is introduced into the chamber 11 through the member 13 by gravity or pressure flow. The fibrous solution contact zone is designed to be sufficient to allow the core 10 to be completely covered with sheath-forming material prior to entering the die 12. The relative amount of solution coated on the core fiber is controlled by the geometry of the die opening, the rheological properties of the solution, and the drag and pressure driven flow. The bonded sheath core fiber 14 exits the die 12 and enters the acid bath 15 where the sheath material solidifies. The outer core fiber 14 exits the acid bath 15 and is washed with the water washing liquid 16 and then collected on the take-up roll 17.

Referring now to FIG. 2 more specifically, the core material 10 is shown having a sheath material 18 surrounding the core material. Satisfactory fibers are produced in which the core 10 is 20 microns in diameter and the sheath material 18 is 1 micron thick. Thicker outer layers are also produced by increasing the pressure imposed on the member 13.

In Figure 3, a 1250x magnification scanning electron micrograph of the sheath core fiber shown in FIG. 2, the unstretched dents appear, indicating that the surface is not oriented and the surface area is improved. Both of these properties contribute to high absorbency and thereby comfort and saltiness. Methods of producing such fibers are described in detail in the following examples using nylon 66 for the core and viscose rayon for the exterior. Although the present invention has been described with respect to these two materials and this is a preferred combination, it should be borne in mind that other core materials and other exterior materials are anticipated within the scope of the present invention.

Example 1

The already oriented nylon fibers were passed through a commercial viscose rayon solution and then drawn through a die. The core fiber was nylon 66 and 20 microns in diameter. The die opening was about 800 microns and the resulting rayon shell was 1 micron thick. A linear velocity of 30.48 m / min (100 feet / min) was used with a commercial concentration spinning bath consisting of 9 wt% sulfuric acid and 13 wt% sodium sulfate. Of course, much larger linear velocities can be used and other die openings and / or higher pressure heads can also be used. The resulting fiber essentially retains the bulk mechanical properties of the nylon core and is rayon-flammable.

Typically, commercial rayon fibers are made from a solution containing about 7% cellulose and 7% alkali in the form of sodium xanthate. Acceptable viscosities for spinning are achieved by aging the viscose solution for 4-5 days. The fibers are made by extruding a thin filament of this solution from a spinning bath where cellulose is regenerated and solidified from its xanthate form. This is done under tension and orientation occurs in the rayon fiber bundle whose level is controlled by the tension, the cellulose source and properties, and the concentration and temperature of the spinning bath.

In the present invention, the core material has a tensile load so that the sheath material exhibits very little orientation even if it is damaged, as opposed to conventional rayon fibers that are spun under tension to show the orientation-related strength. This results in ripples on the surface, which results in an improved surface area that contributes to high absorbency and great salting. Moreover, because the core material has a tensile load, the acid bath as shown in FIG. 1 may be remote from the front face of the die, thus eliminating the need for a die having a precious metal front face when practicing the present invention. In addition, a wider variety of types of viscose solutions can be used since this process does not require a viscose solution that can be drawn into fibers.

Although core material 10 is shown as a single monofilament, it should be borne in mind that multiple filament bundles, such as yarns, which can also be used as core material, fall within the scope of the present invention.

Although the present invention has been described in the preferred embodiments, it is believed that slight changes can be made without departing from the spirit and scope of the invention.

Claims (5)

It is formed from a polymer-formed material in liquid form and is not easily separated from the inner continuous core, remains on the core during the final use of the fiber, is made from a non-thermoplastic material, and has a continuous attachment with minimal orientation. Sexual organic polymeric sheath: consisting of an inner continuous core made of oriented thermoplastic, completely enclosed by an external field, and characterized by an exterior core fiber characterized by a recessed micro-surface which yields an improved surface area with high absorbency and excellent flammability. The exterior core fiber according to claim 1, wherein the core inside is made of a material selected from the group consisting of polyester, nylon, acrylic, and olefin as a raw material. The sheath core fiber according to claim 1, wherein the sheath is made of a material selected from the group consisting of regenerated cellulose and regenerated protein. The cladding core fiber according to claim 2, wherein the sheath is made from a material selected from the group consisting of regenerated cellulose and regenerated protein. A material selected from the group consisting of regenerated fibers and regenerated proteins that are formed from a polymeric sheath forming material in liquid form, are not readily separated from the inner continuous core, remain on the core during the final use of the fiber, and have minimal orientation A continuous adherent organic polymeric sheath; And an inner continuous core composed of oriented thermoplastics selected from the group consisting of nylon, polyester, polyacrylic and polyolefin completely enclosed, yielding an improved surface area of high absorption and good salting property on the recessed micro surface. Exterior core fiber.

Images