JPH0593311A - Method for producing nonwoven fabric - Google Patents

Abstract

(57) [Summary] [Purpose] Widening the product with a narrow-width spinning machine
Provided is a novel method for producing a non-woven fabric, in which the unit weight can be easily changed and the unit weight and the tenacity of strength are excellent even in production. When a nonwoven fabric of a thermoplastic fiber-forming polymer is produced using a spinneret having a series of many spinning orifices and gas ejection slits arranged adjacent to the orifices, the both ends of the spinneret are The spinning orifice pitch is twice as large as the central spinning orifice pitch, and the net surface of the collecting net provided below the spinning orifice is in the same direction as the arrangement direction of the spinning orifices. A method for producing a non-woven fabric, characterized in that the entire collecting net is traversed at an integer number of one or more reciprocations in a direction perpendicular to the direction in which the spinning orifices are arranged while moving the length of the spinneret.

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 non-woven fabric, and in particular, it has a feature that the product width can be freely controlled by a narrow spinning machine with a spinneret width and the width can be easily widened. It relates to the cloth making method.

[0002]

2. Description of the Related Art In recent years, the market for nonwoven fabrics has been expanding rapidly. Among them, the demand for non-woven fabrics produced by the melt blow method is rapidly increasing because they have softness, drapeability, excellent filtration characteristics and the like. On the other hand, even in the field of such non-woven fabrics, materials having higher performance and higher functionality are required, and in addition, there are a wide variety of applications, and a production method corresponding to various kinds is required.

As a method for producing a non-woven fabric by the melt blow method, there are disclosed in JP-A-49-48921 and JP-B-60-5.
It is proposed in Japanese Patent No. 6825. However, although these methods have relatively low equipment costs and are suitable for small-scale production,
Since the manufacturing width is determined by the width of the spinneret, it was necessary to prepare various kinds of spinners to match the product width or prepare for loss due to width cutting. When the width is further increased, it is more difficult to achieve uniformity by squareness, and in actual production, a very advanced technique is required to obtain a uniform and good nonwoven fabric with a wide width.

Therefore, there has been a demand for realizing a method for producing a non-woven fabric capable of efficiently producing a non-woven fabric with a more uniform quality, capable of efficiently controlling the product width with simpler equipment. In response to the above demand, the present inventors have previously proposed a method for manufacturing a nonwoven fabric for widening the product by traversing the collecting net in a direction perpendicular to the arrangement direction of the spinning orifices even in a narrow spinning machine with a spinneret width. ..

However, with such a method, it is possible to easily achieve product widening, change the basis weight, etc., and to operate stably, but since the orifice pitch of the spinneret used is the same over the entire width, it is inevitable There is a problem in that the overlapping portion of the parts is likely to be thick and the uniformity of the areal weight is lacking. Therefore, there has been a demand for the development of a method for manufacturing a non-woven fabric with improved uniformity, which solves the above problems.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to make it possible to easily widen the product and change the date by using a spinning machine with a narrow spinneret. The present invention also provides a novel method for producing a non-woven fabric which is excellent in unit weight and strength uniformity in production.

[0007]

The method for producing a nonwoven fabric of the present invention which achieves the above object uses a spinneret having a series of many spinning orifices and a gas ejection slit arranged adjacent to the orifices. In producing a nonwoven fabric of a thermoplastic fiber-forming polymer, a spinneret in which the spinning orifice pitch at both ends of the spinneret is processed at a pitch twice that 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 arranging direction of the spinning orifices, the entire collecting net is perpendicular to the arranging direction of the spinning orifices. It is characterized in that it traverses one or more round trips in the direction.

The present invention will be described below 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 supplied to a spinneret 2 via a gear pump in a fixed amount, and continuously fed from a series of many spinning orifices incorporated in the spinneret 2. Spun. Also the base 2
A gas jet slit connected to the high-speed gas source 3 is arranged adjacent to the fiber, and the spun yarn from the spinning orifice is drawn and thinned by the high-speed air stream jetted from the gas jet slit to form a fiber stream 4.

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

Further, in the spinneret, as shown in FIG. 2, the spinning orifice pitch at both ends (l) is twice the orifice pitch at the central portion (L) (usually 1.5 to 2.5 times, preferably 1). It is processed and arranged at a pitch of 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 direction of arrangement of the spinning orifices, and the movement of the net surface of the collecting net is in the same direction as the direction of arrangement of the spinning orifices. It is in. This means that the product width can be adjusted arbitrarily. That is, the traverse width of the collection net can be arbitrarily changed by changing the position of the limit switch 9.10, so that even if the mouthpiece width is narrow, the width can be easily widened. In the conventional method, since the moving direction of the net surface of the collecting net is a direction perpendicular to the arrangement direction of the spinning orifices, therefore, the product width is determined by the spinneret width, but the method of the present invention is adopted. By doing so, it is not necessary to prepare many things with different base widths,
Also, there is almost no loss due to ear cutting.

The second point of the present invention is that the orifice pitch at both ends of the spinneret is doubled with respect to the central orifice pitch. This means that when a nonwoven fabric is manufactured, the discharge amount of the polymer per orifice is the same, so that the dates of the narrow orifice pitch portions at both ends are half of the basis weight of the dense orifice pitch portion at the central portion. And by superimposing the both ends, the same basis weight is obtained as a whole. Therefore, it is possible to manufacture a non-woven fabric having an extremely smooth overlap in which the overlapping portions are hardly noticeable, instead of overlapping in a stepwise manner as in the case where the orifice pitches of the spinneret are the same pitch over the entire width. As a result, a non-woven fabric excellent in unit weight and tenacity is obtained. The length (l) of both ends of the spinneret is not particularly limited, but is preferably 10 mm or more and 70 mm or less, more preferably 20 mm or more and 50 mm or less.

A third point of the present invention is that the length of the spinneret width (the length of L + 1 is referred to as spinneret width. The same applies hereinafter) in the same direction as the arrangement direction of the spinning orifices on the net surface of the collecting net. The point is that the whole collecting net is traversed at an integer number of times of one reciprocation or more in a direction perpendicular to the arrangement direction of the spinning orifices during the movement. This means that the number of layers of the product (the number of layers for the L portion; hereinafter the same) can be arbitrarily adjusted. That is, if the collecting net is reciprocated n times while the net surface moves by the length of the mouthpiece, the product is laminated in 2n layers (n: positive integer) in a V shape as shown in FIG. is there. However, when the number of reciprocations of the plaverse is not an integral number of times, the product does not have a uniform V-shaped lamination and the number of laminations becomes uneven. Also, if the traverse is less than one round trip, the end of the product will not be connected. From the above, while the collection net surface moves by the length of the mouthpiece, the entire collection net will make one round trip or more. Traversing an integral number of times is important. The product can be widely used for various purposes by freely adjusting the number of laminated layers according to the purpose of use of the product. It is easy to understand that the reason for setting the length of movement of the net surface to the length of (L + l) instead of the actual mouthpiece width (L + 2l) is that it is a necessary condition that the 1 part comrades are stacked while overlapping exactly. Will be done.

Examples of the thermoplastic fiber-forming polymer used in the present invention include polyester type polyamide type, polyacrylic type, polyolefin type, polyvinyl chloride type,
Various materials such as polyurethane-based and polyfluoroethylene-based homopolymers and copolymers that can be formed into fibers can be used.

Further, a sea-island type, a peel-and-divide composite type, a special polymer blend type, etc. are also applicable. In particular, the sea-island type or the peeling-divided composite type is preferable because it is possible to obtain ultrafine fibers by chemical treatment, physical treatment, or a combination thereof after forming a nonwoven fabric.

Further, the distance between the die surface and the collecting net surface or the suction force from the back surface of the collecting net to be adjusted by a suction device is appropriately adjusted in consideration of the type of the polymer used, the unit weight of the product, the thickness and the like. It is important to select the optimum conditions.

The non-woven 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 the homogeneity of the non-woven fabric having a relatively weak self-adhesive property depending on the polymer used. Entangling treatment, needle punching treatment, fusion treatment, adhesion treatment, etc. are performed depending on the purpose.

In the method of the present invention, since the product width can be widened by the narrow spinning machine having a spinneret width, there is little loss of product type switching (unit weight, product width, resin change, etc.), and it is advantageous for a wide variety of products. The method for producing a nonwoven fabric of the present invention can be applied to the production of various nonwoven fabrics such as a spunbond method and a flash spinning method, but is particularly suitable for a melt blow method.

[0020]

EXAMPLES The embodiments of the present invention are shown below, but the present invention is not limited thereto. Example 1 A polyurethane resin having a spinning temperature of 225 ° C., a spinning orifice diameter of 0.3 mm, and a central orifice pitch of 1.
The length is 270 mm at 0 mm pitch, and the orifice pitch at both ends is 2.0 mm pitch, 30 mm each.
Using a spinneret with the same length as above, the discharge amount per orifice was 0.3 g / min, and heated air of 225 ° C. was jetted at 2300 Nl / min from the adjacent gas jet slits to continuously discharge it with the device shown in FIG. A non-woven fabric was manufactured. At this time, the traverse width of the collecting net is 1200 mm, and while the net surface moves 300 mm in the same direction as the spinning orifice, the entire collecting net is reciprocated once in the direction perpendicular to the spinning orifice and laminated in two layers in a V shape. It was The obtained non-woven fabric has an average basis weight of 75 g / m ² and has a uniform basis weight on the entire surface of the product.
It showed a good appearance with almost no noticeable lamination marks, and was suitable as a base fabric for clean engineering, textiles, base fabric for sports clothing, or a base material for industrial materials.

Example 2 Using the same spinneret apparatus as in Example 1, the polyester elastomer resin was spun at a spinning temperature of 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 non-woven fabric was laminated in four layers and had an average basis weight of 50 g / m ² . This product had a uniform basis weight and excellent uniformity of breaking strength in the vertical and horizontal directions, and could be applied to various fields as a clothing material or an industrial material.

[0022]

The present invention has the following unique effects. (B) Since a wide non-woven fabric can be obtained even with a narrow spinning machine having a spinneret and the product width can be made according to the purpose of use, there is almost no ear loss. (B) Since it is laminated in a V shape, a nonwoven fabric having excellent unit weight in the vertical direction and horizontal direction of the product and uniformity of strength can be obtained. (C) Suitable for small lot high-efficiency production because there is little loss of product type switching (weight, product width, resin change, etc.). (D) The nonwoven fabric obtained by the present invention can be widely used in various applications such as filter materials, leather substrates, cleaners, wipers and clothing materials.

[Brief description of drawings]

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

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

FIG. 3 shows an example of a non-woven fabric in which a fiber stream produced by the method of the present invention is laminated in two layers in a V shape.

Claims (1)

[Claims] 1. A process for producing a nonwoven fabric of a thermoplastic fiber-forming polymer using a spinneret having a series of spinning orifices and gas ejection slits arranged adjacent to the orifices, wherein both ends of the spinneret are manufactured. Is a spinneret in which the spinning orifice pitch of the portion is twice as large as the pitch of the spinning orifice in the central portion, and the net surface of the collecting net provided below the spinneret is the arrangement direction of the spinning orifices. A method for producing a non-woven fabric, which comprises traversing the entire collecting net in an orthogonal number of one or more reciprocations in a direction perpendicular to the arrangement direction of the spinning orifices while moving in the same direction by the length of the spinneret width.