JPH0336948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a nonwoven fabric that is strong in the vertical and horizontal directions, and more specifically, after vertically stretching an unoriented and stretchable long fiber random nonwoven fabric, The present invention relates to a method for producing a strong nonwoven fabric that is orthogonally laminated after being stretched, by laminating and bonding in warp and warp directions, or laminating and bonding a long fiber nonwoven fabric that has been stretched vertically and a long fiber nonwoven fabric that has been stretched horizontally.

[Prior art and problems to be solved by the present invention]

Conventional random non-woven fabrics have good bulk and texture, but cannot provide the strength of woven fabrics. Random nonwoven fabrics also have good water permeability and filter properties. In recent years, nonwoven fabrics have been attracting attention as geotextiles (fiber materials for civil engineering), due to their water permeability and filter properties. However, the biggest problem with using random nonwoven fabrics as geotextiles is that they lack strength. As a method for manufacturing strong nonwoven fabrics, the present inventors have proposed a number of orthogonal nonwoven fabrics in which a web strong in the vertical direction and a nonwoven fabric strong in the horizontal direction are laminated and bonded together. As an example, there is Japanese Patent Publication No. 59-6943 which uses a filament tow manufacturing device, and as a specific means for making the tows orthogonal, a lamination method using a longitudinal and longitudinal laminating machine was proposed in Japanese Patent Publication No. 53-38783. However, this method of using tow manufacturing equipment requires high-speed mass production type tow manufacturing equipment, and is not suitable for manufacturing nonwoven fabrics in high-mix, low-volume production. The present invention provides a specific means for producing an orthogonal nonwoven fabric by using a long fiber random nonwoven fabric such as a spunbond nonwoven fabric as a raw material and stretching it.

Those skilled in the art would easily think of simply stretching conventional nonwoven fabrics, but even if they were actually stretched, it would not be possible to stretch or orient the filaments or rearrange the arrangement of the filaments. I couldn't stop. This may be due to inappropriate stretching means, but there has been insufficient research into stretching nonwoven fabrics.

In the present invention, as a result of research into why conventional nonwoven fabrics cannot be sufficiently stretched, the following conclusions were reached as a result of research into both the raw material nonwoven fabric and the stretching means required for stretching. Ordinary random nonwoven fabrics are bonded by filament entanglement or adhesion, but since their bonding strength is weaker than the strength of the filaments, the stretching process simply destroys these bonds and the filaments Stretching and rearrangement could not be realized. In addition, the method of stretching is also poor, and when simply stretched, nonwoven fabrics made of entanglement and adhesive strength have uneven thickness, uneven entanglement, and uneven adhesive strength, and when stretching force is applied, the nonwoven fabric becomes wide. Stress was concentrated at the weakest point in the area, causing the film to break at that point, making it impossible to achieve high-magnification stretching.

[Means for solving problems]

As a result of intensive research into these problems, we have arrived at the solution described below.

As for random nonwoven fabrics, which are raw materials, wet or dry nonwoven fabrics are aggregates of short fibers, but unless the short fibers are strongly bonded by entanglement or adhesive force, they cannot become strong nonwoven fabrics. Even if such a nonwoven fabric is stretched, the bonded portions will interfere, making it difficult to stretch. Further, even if a stretching force is applied to a nonwoven fabric made of such short fibers, it is difficult to uniformly transmit the stretching force to all the short fibers. In addition, nonwoven fabrics that are unsuitable for stretching include nonwoven fabrics made of long fibers that have too fine a denier (0.1 denier or less), or nonwoven fabrics that are made of filaments that contain air bubbles or a large amount of foreign matter in the filaments. Bad sex. Furthermore, in order to aim for high strength, conventional long-fiber nonwoven fabrics have a problem in that they are made into strong filaments in a process prior to making the nonwoven fabric, such as the spinning stage. In this case, the strength of the filament is stronger than the entanglement and adhesive strength,
The drawing process simply breaks this bond and does not allow the filament to be drawn or realigned. One point of the present invention is that the filament, which is a raw material, is processed into a nonwoven fabric in a state in which it has hardly been stretched (unstretched or unoriented filament). Unoriented filaments have the following properties: It has a low yield point strength and can be stretched with small force. If it is stretched at the appropriate temperature, it has sufficient elongation and shows an elongation of several hundred percent. Filament stretched at the appropriate stretching temperature exhibits high strength at room temperature. Due to these characteristics, unoriented filaments can be made into sufficiently strong filaments by stretching at an appropriate temperature. When a nonwoven fabric made of these unoriented filaments is stretched at a suitable stretching temperature, the nonwoven fabric as a whole is stretched with a tension that is lower than or not significantly different from the entanglement strength. Although the filaments themselves are stretched, it has been experimentally confirmed that the filaments themselves are rearranged in the process of stretching the nonwoven fabric as a whole, and are aligned in the stretching direction as a whole. It was confirmed that by such stretching, the vertical/horizontal strength ratio of the nonwoven fabric, which was about 7:3, was increased to more than 5:1 to about 10:1.

Of course, what is defined as an unoriented filament in the present invention does not mean that the degree of orientation is zero in the strict sense, but it is possible to further stretch it by several hundred percent (preferably 200% or more) if it is stretched at an appropriate temperature. means a filament. In order to spin a filament with good drawability, it was found that the orientation could be reduced by not applying too much draft, but by air injection, etc. If a draft is applied, heating the air to above the melting point can reduce the orientation.

The long-fiber random nonwoven fabric of the present invention may be arranged somewhat vertically or horizontally, as in the case where it is produced by a normal nonwoven fabric manufacturing method, but it is usually arranged slightly in the vertical direction in many cases. . When such a nonwoven fabric arranged vertically is subjected to horizontal stretching as described below, the stretching effect is small because there are few filament components arranged horizontally. Therefore, as a method for manufacturing a nonwoven fabric made of filaments with increased horizontal content and good stretchability, several air holes are provided around the spinneret for spinning the filaments, and air is ejected diagonally to scatter the filaments in a spiral shape. Furthermore, if two air holes are provided on the outside of the nonwoven fabric and the two air jets are injected parallel to the direction of travel of the nonwoven fabric and intersect on the extension line of the spinneret, the air collides and is perpendicular to the direction of travel. It was found that the filaments of the nonwoven fabric had more components arranged horizontally. When the air is heated to a temperature higher than the melting point of the polymer to be spun, the filaments are easily scattered, and the resulting filaments have little orientation despite being drafted by the air. Based on this idea, by spreading outside air in the traveling direction of the nonwoven fabric, it is possible to manufacture a nonwoven fabric with filaments arranged vertically, and it is also suitable as a raw material for a nonwoven fabric that is vertically stretched or rolled.

When manufacturing a nonwoven fabric made of unoriented filaments, the filaments can be joined mechanically such as by needle punching, but by taking advantage of the good adhesive properties of unoriented filaments, it is possible to join them together into a nonwoven fabric only by embossing. . Further, the filament may be conjugated with an adhesive polymer, or the adhesive polymer may be separately spun and mixed. Adhesives such as powder adhesives and emulsion adhesives can also be used. These types of adhesives often require adhesives when ultimately joining webs that are strong in the vertical direction and webs that are strong in the horizontal direction, so we make a comprehensive judgment based on these factors and the requirements of the application. It is determined.

There are many methods for stretching conventional fibers and films, but as a result of intensive research on the most suitable method for stretching the nonwoven fabric made of unoriented filaments of the present invention, we found that the following method is the most suitable. It turned out to be. For vertical stretching, proximity stretching and rolling stretching are most suitable. For horizontal stretching, methods using grooved rollers and horizontal stretching using pulleys are most suitable for the present invention. For these devices,
Since this will be explained in detail in the explanation section of the drawings, only the characteristics of each stretching means will be described here.

In general, nonwoven fabrics have uneven thickness and uneven intertwining of filaments, and even worse, if the thickness is thin and the entanglement is small, this becomes doubly bad. In order to stretch such a nonwoven fabric in the vertical direction, the conventional method of simply stretching it between nip rolls under heating results in unevenness in the nonwoven fabric and unevenness in the heat when heated. As a result of experiments, it was found that even if force is applied to a wide area of a sheet in this state, the stress is concentrated at the weakest point, making it impossible to achieve uniform and stable high-magnification stretching. Therefore, if the preheated nonwoven fabric is subjected to stretching stress in a narrow range, and then rapidly stretched in that narrow range,
As the filaments are entangled or bonded within that range, it has been found through experiments that even if there is some thickness unevenness or uneven entanglement of the filaments, uniform stretching can be achieved. Specific means thereof include proximity stretching, rolling, and horizontal stretching using grooved rolls.

Proximity stretching and rolling as vertical stretching means have already been used in films and nets, and the present inventors have already made prior inventions for these. Special Publication No. 61-55456 and No. 62-97829
Therefore, the present invention can be said to be an additional invention to those earlier inventions. Proximity stretching is roller stretching, where the distance between stretches is extremely narrowed, and in normal film stretching, the width of the film after stretching is not much narrower than before stretching, and the stretched film is transparent. This technique is used for the purpose of having good properties and ensuring that the tear strength in the longitudinal direction does not become too weak even though it is a longitudinally stretched film. The use of proximity stretching in the present invention is completely different and is used as a means for uniformly stretching the nonwoven fabric. Considering the principle behind uniform stretching, if the stretching zone is set below the range where filaments are randomly reciprocated, many filaments cross between the filament being stretched and before stretching. Therefore, even if stretching stress is applied, the filament will not be stretched and the stress will not be concentrated on uneven thickness or the like and the filament will not break. Rolling is performed by making the stretching zone of this close stretching less than the thickness of the nonwoven fabric and applying stress vertically while crushing the heated nonwoven fabric, and in principle it can be said to be superior to close stretching. However, wide-width equipment has problems such as high equipment cost, narrow range of operating conditions, and the tendency for wrinkles to form in the nonwoven fabric after rolling.

Next, the horizontal stretching method will be described.

The tenter method, which is commonly used as a method for horizontally stretching webs such as films and mesh materials, has disadvantages such as a huge increase in equipment costs, the need for a large floor area, and poor heating energy efficiency. However, it cannot be said to be an appropriate stretching method, especially when a large variety of products are produced in small quantities, such as in the case of nonwoven fabrics. As a prior invention, the present inventors have proposed a simple but reliable stretching method that utilizes a pulley as a means for horizontally stretching a film or net-like body, and also allows for easily changing the stretching ratio and degree of heat treatment. (Japanese Patent Publication No. 57-30368 and Japanese Patent Publication No. 62-97825). A number of advantages were found when this method was applied to the drawing of the long fiber random nonwoven fabric made of the unoriented filaments of the present invention. In addition to the advantages of simple equipment, low equipment costs, small floor space, and good energy efficiency, nonwoven fabrics also have the need to freely change the product width depending on the application, and can be stretched depending on the thickness of the raw materials and the degree of entanglement. Since the magnification must be slightly changed, this simple stretching method allows the width and stretching magnification to be easily changed during operation.
Due to these advantages, it has been found that transverse stretching using pulleys is very suitable for the present invention. To specifically explain the horizontal stretching means using pulleys, a pair of left and right pulleys having the same circumferential speed are arranged symmetrically across the center line so that their outer peripheries have a trajectory that widens toward the end, and a pulley is formed on the outer periphery of the left and right pulleys. The belt under tension, which is fitted into the belt groove of the and a belt, and stretch it horizontally on a widening track created by a pair of pulleys. In the case of heating with hot water stretching, by immersing the widening raceways of the pulley in hot water, it is possible to make a compact stretching device by taking advantage of the good heat conductivity of hot water. In the case of hot air heating, allowing the hot air to penetrate through the nonwoven fabric has the advantage of having good thermal conductivity and making the device compact and simple. However, if the nonwoven fabric is thick and hot air cannot pass through, it is necessary to heat the nonwoven fabric from the front and back sides. When the nonwoven fabric first enters the pulley, there is a parallel section where it is not stretched too rapidly, and this section can be used as a preheating zone. There is also a part at the end of the stretching where the stretching is not very rapid, but this part can be used as a heat treatment zone. However,
Depending on the position of the nonwoven fabric away from the pulley, it is possible to take out the nonwoven fabric in a state that has hardly been heat treated, and it is possible to create various heat treatment conditions from fixed length heat treatment to contraction heat treatment.

As another horizontal stretching means, a grooved roller in which the diameter of one roller has many peaks, valleys, and valleys in the axial direction is used, and the pair of grooved rolls are combined to so that the troughs of the grooved roll and the grooved roll of the other side engage with each other,
By nipping the nonwoven fabric of the present invention between them, it is stretched horizontally. After the horizontally stretched nonwoven fabric is stretched out, it is further stretched horizontally through such a grooved roll. By performing such operations in multiple stages, the stretching ratio can be increased, and by passing through multiple stages where uneven elongation occurred in one stage, it has become possible to achieve uniform stretching in the entire transverse direction. The advantage of this method is that the equipment is very simple and that the nonwoven fabric can be divided into many pieces in the horizontal direction and stretched little by little. This is ideal for stretching materials with non-uniform thickness and entanglement, such as non-woven fabrics. Stretching using a grooved roll is a method that has already been used for films (Japanese Patent Publication No. 59-32307), but the present invention is a nonwoven fabric made of unoriented filaments, and most of the filaments are arranged horizontally. It is characterized in that it is used as a means for stretching a nonwoven fabric, and is further characterized in that the horizontally stretched nonwoven fabric and the vertically stretched nonwoven fabric are laminated and bonded.

Next, we will discuss the warp and warp stacking means.

As for means for laminating non-woven fabrics stretched in the vertical direction, the Japanese Patent Publication No. 53-38783 mentioned above is effective, and in addition to this, the Japanese Patent Publication No. 55-51058 and the Japanese Patent Publication No. 55-51058, which were also earlier inventions by the present inventors, Kosho 49-48580 etc. can also be used. To explain the method in detail, a horizontal web fed from a direction perpendicular to the running direction of the vertical web is cut to approximately match the width of the vertical web, and the overlapping of the horizontal web is adjusted to the minimum while cutting continuously. In this method, the vertical web is overlapped with the vertical web, and then the vertical web and the horizontal web are bonded to form a warp/warp orthogonal nonwoven fabric. The biggest feature of this method is that it is an extremely productive device, and even with a wide machine of 3 m or more, it can stack warp and warp at a speed of 40 to 50 m/min. Furthermore, by adhering the vertically oriented nonwoven fabric and the horizontally oriented nonwoven fabric by orthogonal lamination, there is also the effect of repairing the bonding force between filaments that have come off or broken during the stretching process. Through this orthogonal lamination,
The non-woven fabric is strong both vertically and horizontally, and has more than three times the tensile strength compared to regular random non-woven fabrics with the same basis weight, as well as impact strength, tear strength, puncture strength, etc.
The perforation strength is also improved several times. In addition, since the Young's modulus is 5 times or more and the elongation is also reduced, the dimensional stability against external forces, which has been a drawback of conventional nonwoven fabrics, can be significantly improved.

In addition, the lamination and adhesion of a vertically stretched web and a horizontally stretched web has been proposed as an earlier invention by the present inventors, such as a horizontally stretched web made from a film (Japanese Patent Publication No. 62-28226) and a filament spun by centrifugal spinning. (Japanese Patent Publication No. 57-35301), and can be said to be an additional invention to those inventions, but the present invention is characterized in that it uses an unoriented long fiber random nonwoven fabric as a raw material. When vertically stretched webs and horizontally stretched webs are laminated and bonded in this way,
In terms of physical properties, it is very strong, similar to the case of orthogonal weft/width lamination mentioned above.Another advantage over orthogonal lamination is that in the case of orthogonal weft/width, the boundaries of the horizontal webs that are lined up overlap somewhat, and there is no unevenness. However, in the case of laminated adhesion of a vertically stretched web and a horizontally stretched web, there are no such irregular parts, and the nonwoven fabric is uniform as a whole.

The present invention uses (unoriented) (long fiber) (random nonwoven fabric) as a raw material, and (stretches or rolls it vertically) to create a nonwoven fabric that is strong in the vertical direction, and then (cross-width lamination bonding). Another method of the present invention is to produce a strong nonwoven fabric by (unoriented) (long fiber).
(random nonwoven fabric) is used as a raw material, and a nonwoven fabric that is strong in the vertical direction (stretched or rolled vertically) and a nonwoven fabric that is strong in the horizontal direction (stretched horizontally) are laminated and bonded to produce a strong nonwoven fabric. This is a method of manufacturing. Each numbered item in parentheses is already known, and many of them were invented by the present inventors in other fields, but in order to make a strong nonwoven fabric, we combined them and created a high-quality product. We have now invented the most effective means of manufacturing products at high speed and stably.

Raw materials for the nonwoven fabric used in the present invention include:
Any polymer that is stretchable and whose strength increases by stretching can be used, such as polyolefins such as HDPE and PP, polyester, polyamide, vinyl chloride, acrylonitrile, polyvinyl alcohol, and polyurethane.

[Explanation with drawings]

The mode of implementation will be specifically explained below with reference to the drawings.

FIG. 1 shows a schematic diagram of a weft/warp orthogonal nonwoven fabric that is the object of the present invention, in which a horizontal web 2 ( Cut a nonwoven fabric (stretched in the length direction and with filaments oriented in the length direction) to approximately match the width of the vertical web as in 1, and adjust the overlap of the horizontal webs 2', 2'', etc. to the minimum. Then, the vertical web and the horizontal web are bonded together to form a perpendicular non-woven fabric.The details of this perpendicular laminating device are shown in the previously mentioned Japanese Patent Publication No. 53-38783, etc., and will be described here. The adhesion between the vertical nonwoven fabric and the horizontal nonwoven fabric after orthogonal to the weft and weft is omitted.
Adhesive component contained in both or one side of the horizontal nonwoven fabric (filament coextruded with the main component polymer,
Separately spun filaments, short fibers, powders,
You can heat the adhesive using foam), or soak it in a liquid adhesive such as adhesive emulsion after laminating the warp and warp.
After squeezing out excess adhesive and drying it by passing it through a heat drum (or hot air chamber, infrared oven, etc.) if necessary, it is made into a product. Of course, mechanical joining such as needle punching may be advantageous in joining the vertical web and the horizontal web.

FIG. 2 shows another embodiment of the present invention in which a vertically stretched nonwoven fabric and a horizontally stretched nonwoven fabric are laminated and bonded, and the nonwoven fabric 1 is vertically stretched and vertically oriented.
The nonwoven fabrics 3 which are horizontally stretched and horizontally oriented are laminated, passed through pinch rolls 4 and 4', passed through a heating cylinder 5, and then compressed with a thermocompression roll 6 to form a laminated nonwoven fabric 7. The adhesive for lamination is the same as in the case of FIG. 1, and in the case of emulsion, the pinch roll 4 is provided with a glue bath, and the adhesive is supplied by dipping into the glue.

Figure 3 is an example of a manufacturing device for a long fiber nonwoven fabric made of non-oriented but horizontally oriented filaments.
Figure A is a plan view of the spinning nozzle, Figures B and C are nonwoven fabric manufacturing equipment using this nozzle, and Figure B
The figure is a side view of the device, and Figure C is a front view of the device, showing a state in which the filament is spread horizontally. A filament melt constituting the desired nonwoven fabric is discharged from the spinneret 8.
Air holes (10-1, 10-2, 10
-3, . . . usually 3 to 8 pieces) are provided. These air holes are opened slightly diagonally, and the air that comes out intersects the spun polymer melt 9 within a few centimeters to more than ten centimeters from the spinneret 8, causing the melt 9 to rotate in a spiral shape. be done. Air hole 10-
1, 10-2, . . . air is ejected in the direction of travel through other air holes 11, 11' provided on the outside of the 1, 10-2, . The spun filaments that have been rotated are now scattered at right angles to the traveling direction of the nonwoven fabric. Components arranged horizontally are accumulated on the screen mesh 12 running downward, forming a nonwoven fabric 13 mainly composed of horizontally arranged components. Since the spray width of one nozzle is usually in the range of 100 to 300 mm, a large number of these nozzles are arranged horizontally to determine the width of the product. Also, when you want to increase both filament density and line speed,
It is necessary to install multiple stages in the direction of line movement.
Air holes 10-1, 10-2,..., 11, in order to spread neatly in the vertical direction and to prevent molecular orientation of the filament as much as possible.
As a result of experiments, it was found that the air blown out from 11' needs to be heated to several tens of degrees above its melting point. Depending on the type of polymer, it may be sufficient to heat only one of the two types of air. A nozzle like the one shown in Figure 3A is commercially available as a nozzle for applying hot melt adhesive (for example, Nordson Corp. Spray Gun HMS
-20), but the present invention uses such a nozzle,
It is unique in that it is used in the production of nonwoven fabrics made of filaments that are unoriented and arranged vertically.
Furthermore, it is characterized in that it is stretched vertically or horizontally to form a weft/warp orthogonal nonwoven fabric. Rotate the nozzle in Figure 3 by 90 degrees to make the pattern spread by air at 11 and 11' vertically (parallel to the direction of movement of the nonwoven fabric).
By arranging a large number of these nozzles horizontally so that they spread out, it can also be used to produce a nonwoven fabric made of vertically arranged filaments for vertical stretching.

FIG. 4 shows an example of means for longitudinal stretching, in which a long fiber nonwoven fabric 14 made of unoriented filaments is preheated by a heating cylinder 16 via pinch rolls 15, 15', and guided to small diameter rolls 17, 17'. 1
It is vertically stretched in a narrow distance between 7 and 17', heat treated in a cylinder 18, cooled in a cylinder 19, nipped with pinch rolls 20, and taken off as a wide vertically stretched nonwoven fabric 21. This process is 17,
reducing the roll diameter of 17', and 17,
The key is to make the distance between 17' as narrow as possible.

FIG. 5 shows an example of a rolling device, in which a long fiber nonwoven fabric 14 made of unoriented filaments is rolled onto pinch rolls 2.
2 and 22', the material is guided to rolling rolls 24 and 24' via a turn roll 23. rolling roll 24,
24' is heated, and 24 is stretched (rolled) vertically at a speed difference between 24 and 24' while being crushed between 24 and 24', which have been preheated and adjusted to a thickness below the thickness of the nonwoven fabric. The rolled nonwoven fabric 24 is then heat-treated at 24' and nipped at pressure rolls 25.
It was adopted as 6. The feature of this rolling method is that even if the raw nonwoven fabric has some unevenness, it can be stretched to a high magnification.Furthermore, the rolled nonwoven fabric as a whole can have a pearl-like luster, which is completely different. It is also possible to provide the performance of

Next, an example of the horizontal stretching means will be shown.

FIG. 6 shows a nonwoven fabric 27 made of unoriented filaments with many components arranged in the horizontal direction, passed through a turn roll 28, and then passed through a turn roll 28. You will be led to the narrowest part. There is a belt (or rope) 3 on the widening track of the extension pulley.
0 and 30' are circulating under tension, and at this narrowest part, both ends of the non-woven fabric 27 are gripped between the belt and the pulley, and the non-woven fabric 27 is horizontally spread on the trajectory that widens at the end formed by the stretching pulleys 29 and 29'. The nonwoven fabric 33 is stretched in the direction of width and spread out at the widest point of the trajectory, separated from the belts 30, 30' and passed through the turn rolls 31.
It will be taken over as. The extending portion that widens toward the end is covered with a chamber 32 and is heated with hot air, a hot bath, infrared rays, or the like. In the case of hot air, thermal efficiency is good if it is heated so as to penetrate the nonwoven fabric.

FIG. 7 shows an example of horizontal stretching using grooved rolls, in which grooved rolls 34 and 34' are arranged so that the peaks of 34 and the troughs of 34' engage with each other. (preferably) 35 is introduced, and the nonwoven fabric 35 is stretched horizontally using the unevenness of the peaks and valleys. The stretched nonwoven fabric is widened and this step is repeated in multiple stages to increase the stretching ratio. In this method, the stretching efficiency at both end portions deteriorates, but as a countermeasure, both ends of the grooved rolls 34, 34' are made of a low elastic material such as foam or ultra-soft rubber, so that almost the peaks of the grooved rolls 34, 34' By gripping both edge portions of the nonwoven fabric 35 with a roll having the same height as that of the nonwoven fabric 35, the stretching efficiency of both edge portions can be improved. As another method,
By performing this stretching step with a thread or thin tape (for example, polyolefin stretched tape) attached under tension to both ends of the nonwoven fabric 35, the efficiency of stretching the ends of both ends can be improved. I can do it. Alternatively, grooves for circulating a belt or rope may be cut at both end portions of the grooved rolls 34, 34', and both end portions of the nonwoven fabric may be gripped by the belt or rope and stretched horizontally.

〔Effect of the invention〕

In addition to the water permeability, filtering properties, drapability, etc. of random nonwoven fabrics, if it can be made to have the tensile strength, tear strength, and impact strength of woven fabrics, the uses of nonwoven fabrics will be dramatically expanded. I can do it. The present invention has made it possible to have such strength by using random nonwoven fabric as a raw material. Moreover, there is little variation in thickness or strength, and it is possible to achieve stable quality.

Another important property of nonwoven fabrics is that they must be low cost. Since the present invention involves an additional process after the normal nonwoven fabric production line, it is thought that this will lead to an increase in costs, but this is not necessarily the case. The reason is that if the basis weight is the same, the strength is more than three times that of a random nonwoven fabric, so even if the basis weight is reduced, the required performance can be fully satisfied.

Since the raw material non-woven fabric is stretched in the vertical direction,
The line speed is increased by the stretching ratio, and the manufacturing speed of the nonwoven fabric becomes extremely high.

The equipment used in the present invention is all simple, resulting in lower equipment costs, less floor space, and fewer workers. Therefore, the fixed cost of the process can be reduced.

The process of the present invention is fast, and the equipment is compact, so there is little energy loss in heating, driving, etc., and proportional costs do not increase.

In this way, high performance quality can be produced at low cost, opening up new fields such as nonwoven fabrics for civil engineering such as geotextiles, and nonwoven fabrics for reinforcing PVC and rubber sheets that utilize their strength and drape properties. Therefore, non-woven fabrics, which until now could only be used for limited purposes in terms of performance, have the same strength as woven fabrics, and are completely new due to their drapability, texture, water permeability, filter properties, etc. New uses can be developed.

[Brief explanation of the drawing]

FIG. 1 shows a method of laminating vertically stretched nonwoven fabrics at right angles to the warp and warp, and FIG. 2 shows a method of laminating vertically stretched nonwoven fabrics and horizontally stretched nonwoven fabrics. Figure 3A shows the bottom surface of a nozzle for spinning filaments arranged horizontally, Figure B is a side sectional view of an apparatus using this nozzle for producing nonwoven fabrics arranged horizontally, and Figure C shows the apparatus for producing nonwoven fabrics. This is a cross-sectional view of the line viewed from the front, showing the state in which the filament is spread horizontally. FIG. 4 shows an outline of a close longitudinal stretching apparatus for a nonwoven fabric, and FIG. 5 shows an outline of a rolling apparatus for a nonwoven fabric. FIG. 6 shows a device for horizontally stretching a nonwoven fabric using pulleys, and FIG. 7 shows a device for horizontally stretching a nonwoven fabric using grooved rolls. Explanation of main symbols, 1 and 2 are vertically stretched nonwoven fabric, 3 is horizontally stretched nonwoven fabric, 5 is heating cylinder, 8 is spinneret, 10-1, 10-2...11, 1
1' is an air hole, 16 and 18 are heating cylinders, 1
7 and 17' are small diameter rolls, which are used for vertical stretching.
4, 24' are rolling rolls, 29,
29' is a stretching pulley, between which horizontal stretching is carried out, 34,
34' is a grooved roll, and horizontal stretching is performed between these rolls.

Claims (1)

[Scope of Claims] 1. A long fiber random nonwoven fabric made by spinning unoriented filaments, which is stretched or rolled in the longitudinal direction so that the filaments constituting the fabric are substantially stretched and molecular orientation occurs; A method for producing a stretched orthogonal nonwoven fabric, characterized by orthogonally laminating and bonding nonwoven fabrics. 2. A method for producing a stretched orthogonally stretched nonwoven fabric according to claim 1, characterized in that the longitudinal/width tensile strength ratio of the nonwoven fabric stretched or rolled in the longitudinal direction is 5 times or more. 3. In the longitudinal stretching according to claim 1, the stretching zone of the nonwoven fabric heated to an appropriate temperature for stretching is within 1/10 of the width of the nonwoven fabric, and the stretching ratio is 2 times or more. A method for producing orthogonally stretched nonwoven fabric. 4. The vertical rolling/stretching method according to claim 1, characterized in that the nonwoven fabric is rolled while being crushed between a pair of rolling rolls arranged with a spacing smaller than the thickness of the nonwoven fabric and rotating in mutually opposite directions. A method for producing orthogonally stretched nonwoven fabric. 5. A method for producing a stretched orthogonal nonwoven fabric, characterized in that the unoriented filament according to claim 1 has an elongation of 200% or more at an appropriate temperature for stretching. 6. A method for producing a stretched orthogonal nonwoven fabric, which comprises using air heated to a temperature higher than the melting point of the polymer to be spun to scatter the filaments in the spinning of unoriented filaments according to claim 1. 7 In the method for manufacturing a nonwoven fabric for vertical stretching or rolling by spinning unoriented filaments according to claim 1, the filaments extruded from a nozzle are dispersed with heated air swirling in a spiral shape, and then further spun in the advancing direction. A method for producing a stretched orthogonal nonwoven fabric characterized by increasing the number of filaments arranged in the vertical direction by injecting air so as to cross each other. 8. In a long-fiber random nonwoven fabric made by spinning unoriented filaments, a nonwoven fabric stretched or rolled in the vertical direction and unoriented filaments are spun so that the constituent filaments are substantially stretched and molecular orientation occurs. A method for producing a stretched orthogonally stretched nonwoven fabric, which comprises laminating and bonding long-fiber random nonwoven fabrics that have been stretched in the transverse direction so that the constituent filaments are substantially stretched and molecular orientation occurs. 9. A method for producing a stretched orthogonal nonwoven fabric, characterized in that the unoriented filament according to claim 8 has an elongation of 200% or more at an appropriate stretching temperature. 10. A method for producing a stretched orthogonal nonwoven fabric, which comprises using air heated to a temperature higher than the melting point of the polymer to be spun to scatter the filaments in the spinning of unoriented filaments according to claim 8. 11 In the method for producing a horizontally stretched nonwoven fabric by spinning unoriented filaments according to claim 8, the filaments extruded from a nozzle are scattered with heated air swirling in a spiral shape, and then further spun in the direction of travel. A method for producing a stretched orthogonal nonwoven fabric, which is characterized by increasing the number of filaments arranged in the horizontal direction by jetting air so as to cross each other in the perpendicular direction. 12 In the horizontal stretching method according to claim 8, a pair of left and right pulleys having the same circumferential speed are arranged symmetrically across a center line so that their outer peripheries have a trajectory that widens toward the end, and The belt under tension, which is fitted into the belt groove of the pulley, is circulated on the track where the ends of the pulleys almost widen, and the nonwoven fabric is introduced into the narrow area between the left and right pulleys, and the ends of the nonwoven fabric are inserted into the belt groove of the pulley. A method for producing a stretched orthogonal nonwoven fabric, which is gripped between belts and stretched horizontally on a divergent track formed by a pair of pulleys. 13. In the horizontal stretching method according to claim 8, a pair of grooved rollers having multi-stage grooves are combined, arranged so that the grooves of one roll and the peaks of the other roll are engaged with each other, and the nonwoven fabric is stretched out,
A method for producing a stretched orthogonal nonwoven fabric, which is characterized by horizontally stretching the nonwoven fabric by combining these steps in multiple stages.