JP2888679B2 - Nonwoven fabric manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a nonwoven fabric, and more particularly to a direct nonwoven fabric having such features that the width of a product can be freely controlled by a spinning machine having a narrower width and that the width can be easily increased. The present invention relates to a fabric manufacturing method.

[0002]

2. Description of the Related Art In recent years, the market for nonwoven fabrics has been rapidly expanding. Above all, the demand for nonwoven fabrics produced by the meltblowing method is rapidly increasing because they have both softness, drapeability and excellent filtration characteristics. On the other hand, in the field of nonwoven fabrics as well, materials having higher performance and higher functionality are demanded, and in addition, the applications are diversified, and a production method that can handle a wide variety of products is demanded.

A method for producing a nonwoven fabric by a melt blow method is disclosed in JP-A-49-48921, and JP-B-60-5.
No. 6825, for example. However, although these methods are relatively low in equipment costs and suitable for small-quantity production,
Since the production width is determined by the width of the spinneret, it was necessary to prepare various types of spinnerets corresponding to the product width, or to be prepared for losses due to width cut. Further, when the width is increased, the difficulty of achieving uniformity increases by itself, and in order to obtain a uniform and good nonwoven fabric with a wide width in actual production, a very advanced technique is required.

[0004] For this reason, there has been a demand for a method of manufacturing a nonwoven fabric which can efficiently control a product width with simpler equipment and can manufacture a nonwoven fabric of more uniform quality. In response to the above demands, the present inventors have previously proposed a method for producing a nonwoven fabric which widens the product by traversing the collection net in a direction perpendicular to the arrangement direction of the spinning orifices even in a narrow spinning machine having a die width. .

[0005] However, such a method can easily achieve widening of the product, change of the basis weight, and the like, and can operate stably. However, since the orifice pitch of the spinneret used is the same over the entire width, it is inevitable that the ear is not used. There is a problem that the overlapping portion of the portion tends to be thick and lacks uniformity of the basis weight. Therefore, development of a method of manufacturing a nonwoven fabric which has solved the above problems and has improved uniformity has been demanded.

[0006]

[SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, it is an object of broadening of the product by narrow spinning machine of spinneret width, easily it can be changed with the eye Another object of the present invention is to provide a novel method for producing a nonwoven fabric having excellent uniformity of basis weight and strength during production.

[0007]

According to the present invention, there is provided a method for producing a nonwoven fabric, which comprises a series of a large number of spinning orifices and a spinneret having a gas ejection slit disposed adjacent to the orifice. In producing a thermoplastic fiber-forming polymer nonwoven fabric, the spinning orifice pitch at both ends of the spinneret is a spinneret processed at twice the pitch of the central spinning orifice pitch,
In addition, while the net surface of the collecting net provided below the double spinneret moves by the length of the spinneret in the same direction as the arrangement direction of the spinning orifices, the entire collection net is perpendicular to the arrangement direction of the spinning orifices. It is characterized in that it is traversed one or more rounds in the direction an integer number of times.

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing an embodiment of the method for producing a nonwoven fabric of the present invention, and FIG. 2 is a plan view of a die.

In FIG. 1, a thermoplastic fiber-forming polymer heated and melted by an extruder 1 is metered into a die 2 via a gear pump, and is continuously fed from a series of many spinning orifices incorporated in the die 2. Spun. Also base 2
A gas ejection slit connected to the high-speed gas source 3 is disposed adjacent to the fiber, and the spun yarn from the spinning orifice is drawn and thinned by the high-speed airflow ejected from the gas ejection slit to form a fiber stream 4.

Then, the fiber stream 4 moves in the same direction as the fiber stream 4 with the net surface of the collection net and the collection net 5
The whole is collected on a collection net 5 traversing in a direction perpendicular to the fiber flow 4 to form a nonwoven fabric 6 of ultrafine fibers. The nonwoven fabric 6 is sequentially taken up by a take-up nip roll 7 and taken up by a take-up roll 8. At this time, the movement of the net surface can be separately changed by the drive motor 12 and the traverse operation of the entire collection net can be separately changed by the drive motor 11.

Further, as shown in FIG. 2, the spinneret has a spinning orifice pitch at both ends (l) twice as large as the orifice pitch at the center (L) (normally 1.5 to 2.5 times, preferably 1 to 1.5 times). (0.8 to 2.2 times).

The first point of the present invention is that the entire collecting net is traversed in a direction perpendicular to the arrangement direction of the spinning orifices, and the movement of the net surface of the collecting net is made in the same direction as the arrangement direction of the spinning orifices. It is in. This means that the product width can be adjusted arbitrarily. That is, the traverse width of the collecting net can be arbitrarily changed by changing the position of the limit switch 9.10, so that even if the base width is narrow, the width can be easily increased. In the conventional method, the direction of movement of the net surface of the collecting net is perpendicular to the arrangement direction of the spinning orifices, and therefore the product width is determined by the width of the die. However, the method of the present invention is adopted. It is not necessary to arrange many things with different cap widths,
Also, loss due to ear cutting hardly occurs.

A second point of the present invention is that the orifice pitch at both ends of the spinneret is doubled with respect to the orifice pitch at the center. This is the discharge amount of the polymer per 1 orifice upon producing nonwoven becomes half with eyes mining lease orifice pitch portion of both end portions with respect to the basis weight of the dense orifice pitch portion of the central portion are the same. By overlapping these two ends, the same unit weight is obtained as a whole. Therefore, it is possible to produce a nonwoven fabric having an extremely smooth overlap, in which the orifice pitch of the spinneret does not overlap stepwise as in the case where the orifice pitch is the same over the entire width, and the overlap portion is hardly noticeable. As a result, the nonwoven fabric has excellent uniformity of the basis weight and the strength. Then both ends portion of the length of the spinneret (l) is not preferably 10mm or more 70mm or less limited in particular, and more preferably 20mm or more 50mm or less.

A third point of the present invention is that the net surface of the collecting net has the length of the die width (the length of L + 1 is called the die width, the same applies hereinafter) in the same direction as the direction of arrangement of the spinning orifices. In this case, the entire collection net is traversed one or more rounds in the direction perpendicular to the direction in which the spinning orifices are arranged during the movement. This means that the number of layers of the product (the number of layers for the L portion; the same applies hereinafter) can be arbitrarily adjusted. That is, if the trapping net is reciprocated n times while the net surface moves by the length of the base width, the product is stacked in 2n layers (n: a positive integer) in a V shape as shown in FIG. is there. However, the preparative mule <br/> over 'products reciprocal number became stacking number of plaque not if not an integer times the uniform V-shaped stack of. When the traverse is less than one round trip, the end of the product is not connected . From the above, it is important that the entire collection net is traversed one or more rounds an integral number of times while the collection net surface moves by the length of the base. By freely adjusting the number of layers according to the intended use of the product, the product can be widely used for various purposes. Here, the reason why the length of the movement of the net surface is not the actual die width (L + 2l) but the length (L + 1) is that it is easy to understand that it is a necessary condition that the l-parts overlap exactly and are stacked. Will be done.

The thermoplastic fiber-forming polymer used in the present invention includes, for example, polyester polyamide, polyacryl, polyolefin, polyvinyl chloride, and the like.
Polyurethane and polyfluoroethylene-based homopolymers, copolymers, and other various fiberizable materials can be used.

Further, a sea-island type, a separation-split composite type, or a special polymer blend type is also applicable. In particular, it is preferable to use a sea-island type or a split-split composite type, since ultrafine fibers can be obtained by a chemical treatment, a physical treatment, or a combination thereof after forming a nonwoven fabric.

Adjustment of the distance between the base surface and the collecting net surface or the suction force from the back surface of the collecting net by a suction device is appropriately performed in consideration of the type of polymer used, the basis weight of the product, the thickness, and the like. It is important to select the optimal conditions.

The nonwoven fabric obtained by the method of the present invention can be used as it is, but it is preferable to improve the physical properties and uniformity of those having relatively low self-adhesion depending on the polymer used. A confounding process, a needle punching process, a fusion process, a bonding process, and the like are performed according to the purpose.

According to the method of the present invention, products can be widened with a narrow spinner having a spinneret width, so that there is little loss of product change (weight per unit, product width, change of resin, etc.), and it is advantageous for handling various products. Further, the method for producing a nonwoven fabric of the present invention is applicable to the production of various nonwoven fabrics such as a spun bond method and a flash spinning method, and is particularly suitable for a melt blow method.

[0020]

EXAMPLES Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto. Example 1 A polyurethane resin was spun at a spinning temperature of 225 ° C., the spinning orifice diameter was 0.3 mm, and the center orifice pitch was 1.
270 mm length at 0 mm pitch, and orifice pitch at both ends is 2.0 mm pitch, each 30 mm
Using a spinneret having a length of 0.3 g / min and a discharge rate per one orifice of 0.3 g / min, heating air at 225 ° C. was spouted at 2300 Nl / min from an adjacent gas jet slit, and continuously fed to the apparatus shown in FIG. A nonwoven fabric was manufactured. At this time, the traverse width of the collecting net is 1200 mm, and the entire collecting net is reciprocated once in a direction perpendicular to the spinning orifice while the net surface moves 300 mm in the same direction as the spinning orifice, and laminated in two layers in a V shape. Was. The obtained nonwoven fabric has an average weight per unit area of 75 g / m ² and is uniform over the entire surface of the product.
The laminate had a good appearance with little traces of lamination, and was suitable as a base cloth for clean engineering, textile, sports clothing, or a base material for industrial materials.

Example 2 Using a spinneret similar to that used in Example 1, a polyester elastomer resin was spouted at 265 ° C. and heated air at 270 ° C. at 2500 Nl / min to produce a nonwoven fabric. At this time, the traverse width was 900 mm, and the entire collection net was reciprocated twice while the net surface moved 300 mm. The obtained nonwoven fabric was laminated in four layers, and the average basis weight was 50 g / m ² . This material had a uniform basis weight and excellent uniformity of breaking strength in the vertical and horizontal directions, and could be used in various fields as a material for clothing or an industrial material.

[0022]

The present invention has the following specific effects. (A) Even a narrow spinning machine having a spinneret width can produce a wide nonwoven fabric and can have a product width suitable for the intended use, so that ear loss is hardly caused. (B) Since the layers are laminated in a V-shape, a nonwoven fabric having excellent product weight in the vertical and horizontal directions and uniformity of strength can be obtained. (C) Suitable for small lot high-efficiency production due to low loss of product change (weight per unit, product width, resin change, etc.). (D) The nonwoven fabric obtained by the present invention can be widely used for various uses such as filter materials, leather base materials, cleaners, wipers, and clothing materials.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus suitable for the production method of the present invention.

FIG. 2 is a plan view showing an example of a spinneret suitable for the production method of the present invention.

FIG. 3 shows an example of a nonwoven fabric in which two layers of fiber streams produced by the method of the present invention are laminated in a V-shape.

Claims (1)

(57) [Claims] In producing a nonwoven fabric of a thermoplastic fiber-forming polymer using a spinneret having a series of multiple spinning orifices and a gas ejection slit disposed adjacent to the orifice, both ends of the spinneret are used. The spinning orifice pitch of the portion is a spinneret arranged at twice the pitch of the central spinning orifice pitch, and the net surface of the collecting net provided below the spinneret has an orientation direction of the spinning orifice. A method for manufacturing a nonwoven fabric, wherein the entire collecting net is traversed one or more rounds in a direction perpendicular to a direction in which the spinning orifices are arranged while moving in the same direction by the length of the die width.