JPS609157B2 - Manufacturing method of biaxially oriented nonwoven fabric - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a Nimari-oriented nonwoven fabric.

According to the present invention, long fibers having a length of 1.27 skin or more and 1.
A method for manufacturing a patterned nonwoven fabric comprising pouring an aqueous suspension containing short fibers of length 27 from a head box through a mask onto a moving Fourdrinier screen, wherein the mask is arranged at regular intervals. consisting of fluid-impermeable finger-shaped resist surfaces disposed on or above the screen and extending parallel to the direction of travel of the screen, the spacing between the resist surfaces being equal to or greater than the length of the long fibers. so that most of the long fibers and most of the short fibers are placed on the screen between the resist surfaces and the fibers are aligned in a direction parallel to the length of the resist surface. A patterned nonwoven fabric characterized in that it forms stripes of high fiber density, while a small portion of the long fibers are placed across the resist surface and are aligned perpendicular to the resist surface to form stripes of low fiber density. A manufacturing method is provided. Preferably, the resist surface includes approximately equally spaced finger-like striping rods located on or above the screen, the dimensions and spacing of the striping rods being proportional to the high and low fiber densities. A nonwoven fabric consisting of alternating stripes is formed, and most of the long and short fibers in the material are passed between the stripe-forming rods and arranged in the longitudinal direction of the screen, while a small portion of the fibers in the material are passed between the stripe-forming rods. The striping bars are placed across and arranged laterally on the screen.

The present invention will now be further described with reference to the accompanying drawings.

FIG. 1 shows a single layer nonwoven fabric 10 having alternating stripes 11 of high fiber density and stripes 12 of low fiber density.

As can be seen from the figure, the majority of the fibers in the stripe 11 are oriented in a direction approximately following the direction of the moving fourdrinier screen (machine direction) on which the nonwoven is made, i.e. the fibers extend approximately along the length of the nonwoven. Extend parallel. However, the majority of the fibers in stripe 12 are arranged in a direction substantially transverse to the width of nonwoven fabric 10 (lateral alignment), i.e. they are arranged almost perpendicular to the fibers in stripe 11; Bridge these stripes. Such alternating stripe portions having different arrangements are simultaneously formed in the following manner. A nonwoven fabric as shown in FIG. 1 is manufactured by a manufacturing method.

In this method, a blended material of long fibers and short fibers is created,
This material is held in a box in a specific manner to prevent precipitation and separation of solids. The material then flows into the headbox through an inlet distribution device that spreads the flow across the width of the machine, where the flow of material is stabilized. The stabilized material is passed over a fourdrinier wire screen that moves around a perforated coach roll, and suction is applied to the roll to effect dewatering and deposit the fibers onto the screen. The screen carries a fluid-impermeable resist surface in continuous parallel stripes extending in the longitudinal direction of the screen. Alternatively, parallel stripe-forming bars (stripi) extending in the longitudinal direction of the screen may be used.
ngMrs) can also be provided above the screen in the flow path of the material onto the screen. These stripe-forming rods are used in British Patent No. 36 to form non-woven fabrics by depositing an airborne stream of fibers onto a moving screen.
It is similar to the striping rod used in the device described in 906/75. As the material flows over the screen, most of the long and short fibers are drawn to the striping surface, the surface on the screen that is outside the striping rods. This is especially true for short fibers. This is because the short fibers do not attempt to bridge the fluid-impermeable surface because they do not experience forces originating from one or more surfaces outside the fluid-impermeable surface. In effect, due to the movement of the screen, the short fibers are progressively drawn into the portion of the screen between the fluid-impermeable surfaces and are aligned parallel to the machine direction of the web of fibers formed on the screen. At the same time, a small portion of the fibers, especially long fibers, is subject to forces originating from at least two surfaces between the fluid-impermeable surfaces, and this force bridges some of the long fibers across the fluid-impermeable surfaces. Therefore, such fibers are arranged almost perpendicularly to the longitudinal direction of the screen to form long stripes. If the length is smaller than the average length, preferably less than half the average length, the fibers that do not bridge the stripe-forming resist surfaces will be carried in the high fiber density stripes between the stripe-forming resist surfaces. Will.

In high density stripes the majority of the fibers are arranged along the length of the web. As mentioned above, long fibers are 1.2
Short fibers have a length of 7 cm or more, while short fibers have a length of less than 1.27 cm, and are paper fibers, cotton linters or short fibers, thermoplastic fibers, or combinations thereof. It can be.

When short thermoplastic fibers are used alone or in conjunction with other short fibers, they are drawn into stripes of high fiber density and upon thermal activation, long bridges are incorporated into the stripes. The fibers will be bonded at their ends, leaving the bridging fibers with substantially no bonding between stripes of high fiber density, thus improving drapability and flexibility in their faces and throughout the nonwoven. Probably. The spacing between high fiber density stripes of long and short fibers should be at least the width of such stripes, but not so large that the long fibers cannot bridge between each other. Although it is true that some short fibers will be found in the stripes of low fiber density mixed with long cross-linked fibers, most of the short fibers will be located within the stripes of high fiber density. In most of the lightest nonwovens, the top of the nonwoven, the portion of the nonwoven removed furthest from the Fourdrinier screen, contains a small fraction of long and short fibers distributed irregularly, usually across the width of the web. will be covered by

As the fibers in the material flow onto the screen and resist surfaces, or pass through the stripe-forming fins in progressively thicker layers, the fibers act as a water dissipator between the fluid-permeable and fluid-impermeable surfaces. are usually difficult to control,
It falls somewhat irregularly onto the top of the weep. The web in this position can be described more as stripes of high and low fiber density with a somewhat irregular coverage of integrated long and short fibers. Nevertheless, most of the fibers are arranged in a striped pattern in an array parallel to the length of the web. A much more pronounced ribbed structure is obtained if the striping ridges or resist surfaces are moved relatively close and the centers are spaced, for example, 1.905 cm apart.

By "ribbed structure" we mean that stripes with high fiber densities contain so many fibers that the arrangement is approximately semicircular, whereas stripes with low fiber densities are somewhat flattened. The formed web is conveyed by a screen to a belt castle where the fibers are fixed by bonding in said arrangement, for example by applying adhesive to the web or passing under a heater if some of the fibers are thermoplastic. Ru.

Finally, the bonded nonwoven fabric is collected from the screen by a suitable winding device. The nonwoven fabric produced according to the present invention has a variety of uses, and can be used as a disposable curtain or drape, as a pongee-width decorative ribbon and ribbon for flower cultivation, as a sliding leather, as a close-fitting bandage, or as a disposable tablecloth.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a nonwoven fabric produced by the method of the present invention, and FIG. 2 is a flowchart for explaining the method of the present invention. In FIG. 1, 10 indicates a single-layer nonwoven fabric, 11 indicates a stripe with a high fiber density, and 12 indicates a stripe with a low total density. (ZG hit technique 2

Claims (1)

[Claims] 1. A patterned nonwoven fabric made by pouring an aqueous suspension containing long fibers with a length of 1.27 cm or more and short fibers with a length of less than 1.27 cm from a head box through a mask onto a moving Fourdrinier screen. In the manufacturing method, the mask is constituted by equally spaced fluid-impermeable finger-like resist surfaces, which resist surfaces are arranged on or above the screen and extend parallel to the direction of travel of the screen. The spacing between the resist surfaces is smaller than the average length of the long fibers, so that most of the long fibers and almost all of the short fibers are placed on the screen between the resist surfaces and the fibers are exposed to the resist. forming stripes of high fiber density oriented parallel to the length of the surface, while small sections of long fibers are placed across the resist surface and oriented perpendicular to the resist surface to form stripes of low fiber density. A method for producing a patterned nonwoven fabric characterized by forming stripes.