JPS62133164A - Production of nonwoven fabric - 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 [Field of Application] The present invention relates to a method for producing a nonwoven fabric useful as a sanitary material that is thin and soft to the touch.

[Conventional technology]

Traditionally, spunbond materials such as polyester and polypropylene have been widely used for sanitary materials, especially cover stock materials such as disposable diapers and sanitary napkins.In recent years, short fiber nonwoven fabrics made from heat-fusible fibers have become rapidly popular. .

On the other hand, cellulose-based spunbond has high water absorption and tends to become sticky, so it is not used as a cover stock material but as an internal absorbent material.

Furthermore, without being limited to the manufacturing method of such non-woven fabrics, non-woven fabrics using short fibers of about 1.5 denier are generally manufactured industrially, but they are hard to the touch and the denier should be as thin as possible. It is desirable to make the skin softer.

[Problems to be Solved by the Invention] Therefore, attempts have been made to manufacture nonwoven fabrics using ultrafine short fibers such as cL5 denier, but such ultrafine denier short fibers are difficult to open. Since the speed of the spinning machine cannot be increased, productivity decreases, leading to an increase in costs, which is economically disadvantageous.

The inventors of the present invention have carried out intensive research to improve the above-mentioned problems, and as a result, they have completed the present invention. A nonwoven fabric characterized in that splittable composite short fibers consisting of the following components are made into a web using a card, and then all of the fibers are split and fibrillated by jetting a high-pressure liquid stream to randomly entangle them to form an integral structure. It is a manufacturing method.

The present invention will be explained in more detail below.

As a specific example of the cross section of the splittable composite staple fiber in the present invention, as shown in FIG. All of the above incompatible thermoplastic polymer components are arranged alternately and have a cross-sectional shape, but if they can be divided into a plurality of fibrils,
It is not limited to this.

In the present invention, the combination of two mutually incompatible thermoplastic polymer components includes combinations such as polyester and polypropylene, polyester and nylon, and nylon and polypropylene.

The splittable composite short fibers used in the present invention are
636, JP-A-50-5650, etc., composite spun undrawn yarns are bundled and stretched,
It can be obtained by mechanically crimping and cutting into finite fiber lengths to obtain short fibers. TFC, in order to obtain the nonwoven fabric of the present invention, it is preferable to heat-treat the split type composite staple fibers in a wet heat oven by an appropriate method such as dry heat to reduce the boiling water surface shrinkage to 20 inches or less. This also relieves the strain caused by the difference in heat shrinkage on the contact surfaces of the two components, and has the effect of promoting split fibrillation in post-processing.

The thickness of the splittable composite short fibers is about 1 to 5 deniers, and the denier of the split fibrillated single fibers formed by split fibrillation, which consists of at least a part of the components, is 15 deniers or less. Preferably, it should be 11 denier or less, and if it exceeds α5 denier, it will be hard to the touch! In particular, it loses its suitability as a cover stock material for sanitary materials.

Further, it is preferable that the splittable composite short fibers are 20% by weight or less in a card, and single fibers with a weight percentage of 80% or more are completely or partially split by spraying a high-pressure liquid stream. If split fibrillation of a single fiber remains midway and does not completely break apart, several different types of fibrillar fibers are formed between the unsplit thick denier single fiber and the thin denier fibrillar fiber formed by complete split fibrillation. Although denier fibers are mixed, this does not pose any problem in achieving the object of the present invention.

The number of divided segments of the splittable composite staple fiber in the present invention is determined so as to satisfy the above-mentioned denier range (t). Although the number of segments is large, it is difficult to actually increase the number of segments to more than seven, and it is usually advantageous to have a number of segments of 4 to 8 from the viewpoint of ease of manufacturing the fiber.

The denier of the individual segments need not be the same. By controlling the splitting as described above, a nonwoven fabric having the desired performance can be obtained without reducing the carding speed.

The fiber length of the split type composite staple fiber is 15 to 80, and the number of crimps is 2.
．． A range of 5 to 15 pieces/inch is preferred. Fiber length is 15
If it is less than m, it will be difficult to adjust the split fibrillation by carding, and the obtained web will be cut into pieces, making it difficult to handle. On the other hand, if the fiber length exceeds 80 fibers, problems occur during the process such as fibril fibers divided by carding being cut or neps occurring, making it difficult to maintain a uniform web.

When the number of crimps is less than 2.5 crimps/inch, the intertwining of the fibers becomes weak and the compression recovery property is also reduced. On the other hand, if it exceeds 15 pieces/inch, it is 1 yen 1! The tail becomes too fine and shrinks, and the bulk when made into a web becomes smaller.

In the present invention, such splittable conjugate short fibers are formed into a web using a card by a conventional method, and after cooling, the splittable conjugate short fibers in the web on the card are further divided into fibrils. A high-pressure liquid stream is applied to the web surface to promote fibrillation of split composite short fibers and cause random entanglement. The liquid used as the liquid stream is preferably water or warm water for ease of handling.The hole diameter of the injection nozzle for the liquid stream is preferably LO5 to 1.0, preferably L1 to α4wI&.

The injection pressure is 5 to 50K97m"G, and the spacing between the injection hole and the web is preferably 1 to 153mm, and the spacing is wide.
For example, the jetted liquid stream and air mix and the confounding effect is reduced. In this way, the basis weight of the nonwoven fabric can be increased from 10 to 10,097 m.
If it falls within the range of 2, a nonwoven fabric suitable for sanitary materials can be obtained.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

Example Polyethylene terephthalate with an intrinsic viscosity of α63 (in orthochlorophenol at 25°C) was used as the first component, and M I
The second fraction of polypropylene (A8TM D-123B, 230°C) was melt-spun at a ratio of 2:1 (volume ratio), and wound at 1000 m/min to produce the same material as in Fig. 1(a). A split type composite undrawn yarn with a full cross section was obtained. This undrawn yarn was pulled together and stretched with a roller 55 times at a drawing temperature of 80°C to make the single fiber fineness λ0 denier.
Subsequently, 10 pieces/inch of mechanical winding was applied using a push-crimping machine, and the material was once drawn into a container as a tow. This tow was transferred to an autoclave, subjected to relaxation heat treatment at 130°C for 10 minutes, and cut into 32 lengths. This short fiber was opened at a speed of 100 m/min using a roller card.
After forming a web with a basis weight of 0 g/m2, it is rolled.

Next, using the high-pressure liquid jetting device shown in FIG.
3) Side: Two injection nozzles with hole diameter α15Ia1, distance between holes 1, Omm (5) 97 cm in front and back 10 all around.
2G, in the second stage, water is jetted at a pressure of 20 Kfl/cm"G to split and entangle the constituent fibers of the web. The water used for jetting is stored in a suction box (
6) was removed. Injection nozzle (5) and net conveyor (
The interval of 4) was 501 Ia, and the speed of the net conveyor (4) was 5 m/min. This split fibrillated web is then shrunk in a boiling water bath (7) and dried W1! It was dried in a machine (8) and rolled up in @ Toriiso (9) to obtain a nonwoven fabric having a basis weight of 4597 m''.
Under an optical microscope! When observed, split fibrillated composite short fibers and unsplit composite short fibers were observed.
, is a mixture of fibers, and the single fibers of the carded sea urchin are completely or partially split fibrillated, and the unsplit fibers and split fibrillated fibers, and the split fibrillated fibers and split fibrillated fibers are randomly intertwined with each other. A friend that goes well with you.

The physical properties of the obtained AN nonwoven fabric are shown below.

1) Denier of unsplit single fiber zO denier 2) Denier of split fibrillated single fiber Polyethylene terephthalate 1.24 denier yN IJ Flopylene α13 denier 3
) Proportion of undivided single fibers: 15 cm 4) Fabric weight of non-woven fabric: 4597 m 2) Thickness of non-woven fabric
0.7 m [Effects of the Invention] According to the present invention, a nonwoven fabric can be made into a nonwoven fabric by efficiently forming a web using splittable composite short fibers and then spraying high pressure liquid. , which makes it useful as a cover stock material.

FIG. 1 (a1 to (dl) are cross sections of examples of split type composite short fibers used in the present invention, and FIG. 2 is a side view of a day pressure liquid jet injection device used in the present invention.

1.2... Mutually incompatible polymer components 3... Web, 4... Net conveyor, 5... High pressure liquid jet nozzle, 7... Boiling water bath, 8... Dryer Agent Patent Attorney Toshio Yoshizawa (′□“−＋ f
'Ejl+ (Q) (b) (C1(d
'r paralysis 2 diagram

Claims (1)

[Claims] 1. After forming a web of split composite short fibers made of components that are incompatible with each other using a card, the fibers are split into fibrils by spraying a high-pressure liquid stream to form random entanglements. A method for producing a non-woven fabric characterized by having an integral structure. 2. The method for producing a nonwoven fabric according to claim 1, wherein the splittable conjugate short fibers are a combination of splittable conjugate short fibers selected from the group of combinations of polyester and polypropylene, polyester and nylon, and nylon and polypropylene. 3. The method for producing a nonwoven fabric according to claim 1, wherein the short fibers have a fiber length of 15 to 80 mm. 4. Claim 1, in which the denier of the split fibrillated single fibers made of at least one component split and fibrillated from the splittable composite short fibers is 0.5 denier or less.
Method for manufacturing the nonwoven fabric described in Section 1.