PT100138B - Non-woven fabrics and machinery and processes for their production - Google Patents

Abstract

A non-interwoven fabric which consists of a multiplicity of fibrous groups with the appearance of threads, these groups being interconnected at their joins by common fibres to a diversity of the said groups in order to define a predetermined configuration of perforations in the fabric, these fibrous groups being similar to threads consisting of a diversity of parallel and firmly compacted fibrous segments, at least some of these fibrous groups similar to threads having fibrous segments wrapped circumferentially around at least a portion of the periphery of the said parallel and firmly compacted fibrous segments. <IMAGE>

Description

DESCRIPTION

GIVES

INVENTION PATENT

No. 100 138

APPLICANT: CHICOPEE, North American, established at 317 George Street, New Brunswick, New Jersey 08903, United States of America

EPIGRAPH: NEW FABRICS NOT INTERESTED AND PERFORATED AND MACHINE AND PROCESS FOR ITS PRODUCTION

INVENTORS: Arthur Drelich, Alton H. Bassett, William LJames, John W. Kennette and Linda J. McMeekin, residing in the United States of America

Claim of the right of priority under Article 4 of the Paris Convention of 20 March 1883.

INPI. MOD. 113 R F 18732

Description referring to the CHICOPEE invention patent, American, industrial and commercial, established was 317 George Street, New Brunswick, New Jersey 08903, United States of America (inventors: Arthur Drelich, Alton H. Bassett, William LJames, John W Kennette and

Linda J * McMeekin, residing in the United States of America), for: NEW FABRICS NOT INTERESTED AND PERFORATED AND MACHINE AND PROCESS FOR ITS PRODUCTION

For many years, attempts have been made to produce fabrics that have the strength and other characteristics of woven or knotted fabrics without having to resort to the numerous steps required to produce these fabrics. In order to produce a woven or knotted fabric, it is necessary to produce a thread first * The threads are normally produced by opening and carding the filaments and producing a filament weave. The filament web is condensed into a loose fiber from which a preliminary spinning is produced by bending and stretching these loose fibers. Then proceed to the new rewinding and drawing of several preliminary spinning machines to produce a yarn. In order to produce the final fabric, the threads are woven by a loom to create a woven fabric or are knotted in a complicated gill machine. It is often necessary to treat the yarn with starch or other materials before it can be subjected to processing on the weaving or gillging machines. / <»*

During the last twenty or thirty years, several processes were developed and several attempts were also made to directly produce a fabric from a filament weave, eliminating most and eventually all the steps previously described # Some of these methods involved the use of pins or needles arranged in a matrix · According to these methods the needles are inserted through a filament web to produce openings in the web and to simulate the appearance of a woven fabric · The resulting product is weak and requires the addition of a binder chemical that provides the desired resistance. The addition of the binder substantially modifies the feel, feel, flexibility, appearance and other desirable physical properties and makes it virtually impossible to duplicate the desired properties of the woven or knotted fabric. There are other techniques that imply the use of forces transmitted by gases or liquids, these forces being directed to the filament web arranged in a matrix with a predetermined configuration and in order to manipulate these filaments which allows to obtain the finished product with any of the characteristics of woven or woven fabrics. According to some of these prior techniques, the filament web is supported on a component that has a predetermined topography while being treated by forces transmitted by fluids that alter the configuration of the filaments and produce a non-woven fabric. As examples of the method for producing non - woven fabrics refers US patents ^Nos 1978620 s; 2862251; 3033721; 3081515; 3485706 and 3498874.

Although fabrics produced according to some of the methods previously described have been a great success from a commercial point of view, it does not mean that these fabrics have all the desired characteristics typical of many woven and / or woven fabrics. <All of these techniques were unable to provide combines ··

Desired properties of physical properties in the final fabric or the desired appearance of a woven or woven fabric or both * The prior art methods have also not been able to accurately control the placement of the filaments and the control of the forces on the weft filamentous ·

In general, the fabric must be of uniform construction and must have good resistance. A fabric must have adequate brightness or clarity even if that fabric is of relatively high density. The fabric should not practically release fluff, even if absorbent. The desired combination of properties must be possible to obtain without the addition of chemical binders. The process must be controllable in order to allow the production of fabrics that have desired combinations of physical properties.

Summary of the Present Invention

It is an object of the present invention to provide a non-woven fabric that has excellent resistance in the absence of chemical binding additives.

It is another object of the present invention to provide a fabric that has a uniform appearance and that has uniform and controlled physical properties. It is also another objective of the present invention to provide fabrics that have an excellent pattern of clarity and open areas.

According to some aspects of the present invention, this new nonwoven fabric consists of a multiplicity of yarn-like filament groups in which these groups are virtually as dense and thin as spinning yarns. These groups are interconnected in several joints by fibers that are

- 3 '

common to a multiplicity of groups. These groups define a certain pattern of openings in the final fabric. Each group consists of a multiplicity of parallel and heavily compacted filament segments. At least some of these groups have intricate areas of filamentous segments wound circumferentially around a portion of the periphery of the parallel and strongly corápactated filament segments and also through the filament group. According to these tissue variants according to the present invention there are intricate areas that have a bundle of filaments that project in opposite directions from the intricate area. According to some aspects of the new non-woven fabrics of the present invention, the parallel and strongly compacted filament segments are twisted. This twisting develops from an interconnected area to another adjacent interconnected area or alternatively they are opposed twisting, one of the twisting developing from an interconnected area to an intricate portion by the winding and the other opposite twisting develops from that intricate portion by winding to the adjacent interconnected area. According to several variants of the present invention, the interconnected joints are dense, constituting highly intricate areas consisting of a multiplicity of filament segments. Some of the filament segments in these areas are linear, while others are curved at 90 ° in the segment. There are also other filament segments in the joints arranged according to a diagonal stroke as the segment passes through the joint. Some filament segments develop in the * Z * direction within the intricate areas. The direction * Z 'is considered to be determined according to the thickness of the fabric, thus differentiating from the length or width of the fabric *

According to some variants, the portions intricate by the winding may be located in the center between two joints whereas according to other variants the portions intricate by the winding may be ^- - 4 -

Λ

-U i.

off-center. Still according to other variants, there may be a multiplicity of intricate portions by winding between adjacent interconnected unions.

The brightness and clarity characteristics of the fabrics of the present invention are exceptional, as is the density of the compacted filament groups and interconnected joints, which is higher than that of the non-interwoven fabrics obtained according to the prior art. In some cases, the density of the groups and / or joints may be of the same order of magnitude as the density of the threads in woven or woven fabrics. In addition, in many fabrics of the present invention, the density of the filament group and interconnected joints is quite uniform when compared to the nonwoven fabrics of the prior art. The new methods of the present invention intertwine and intricate filaments with greater accuracy and perfection than the prior art methods, thereby providing fabrics with superior properties.

The fabrics according to the present invention are produced by bringing controlled forces and transmitted by fluids onto a surface of a layer of filaments at the same time that this layer is supported by its opposite surface on a component that has a predetermined topography and also a predetermined pattern of open areas within this topographic space. According to a specific method for the manufacture of new non-woven fabrics, the support component that supports the filament weave is three-dimensional and has a multiplicity of pyramids exposed in a matrix on a surface of that support component. The sides of these pyramids form an angle greater than 55 ° with the horizontal surface of the supporting component. It is preferable that this angle is of the order of 65 ° or higher, emphasizing in advance that the angle of 75 ° provides excellent fabrics was in accordance with the present

-4 * 4 invention. This support component also has a multiplicity of openings which are arranged in the areas where the sides of the pyramids intersect the support component »There are also devices to project adjacent currents of fluid simultaneously against the apex and / or against the sides of the pyramids while the filament layer is supported by the pyramids.

Brief description of the drawings

Figure 1 represents a schematic view of a fabric according to the present invention;

Figure 2 represents a schematic section of the apparatus used to produce fabrics according to the present invention;

Figure 3 represents an expanded perspective of a filamentous web and a topographic support component;

Figure 4 represents a block diagram that summarizes the various steps of the process for the production of fabrics according to the present invention;

Figure 5 represents a diagram of a type of apparatus for the production of fabrics according to the present invention;

Figure 6 represents a diagram of another type of apparatus for the production of fabrics according to the present invention;

Figure 4 represents a diagram of a preferred type of apparatus for the production of fabrics according to the present invention;

Figure 8 represents an enlarged cross section of a topographic support component;

* 6 Figure 9 represents the topographic component represented in figure 8 in plan;

Figure 10 represents an enlarged straight section of a topographic support component;

Figure 11 represents in plan the topographic support component represented in Figure 10;

Figure 12 represents an enlarged cross section of a topographic support component;

Figure 13 represents in plan the topographic support component represented in figure 12;

Figure 14 represents an enlarged cross section of a topographic support component;

Figure 15 represents in plan the topographic support component represented in figure 14;

Figure 16 represents a plan view of a partial topographic component;

Figure 17 represents a cross section in section along line 17-17 of Figure 16;

Figure 18 represents a plan view of a partial topographic support component;

Figure 19 represents a plan view of a partial topographic component;

Figure 20 represents a microphotograph of the fabric schematically illustrated in Figure 1 with a magnification of about 20 times;

Figure 21 represents a photomicrograph of an area of the “tissue joining loops shown in Figure 20 but enlarged even more approximately 4 times;

Figure 22 represents a microphotography of an interconnected union of the fabric represented in

- 7> · Λ

figure 20 but enlarged even more approximately 4 times;

Figure 23 represents a microphotograph of a cross section of a tie ”of the fabric shown in Figure 20 but enlarged approximately 4 more times;

Figure 24 represents a photomicrograph of a fabric according to the present invention but enlarged about 25 times;

Figure 25 represents a photomicrograph of one of the tissue joining loops shown in Figure 24 but enlarged approximately 3 more times;

Figure 26 represents a microphotograph of an interconnected joint of the fabric of Figure 24 but enlarged salts approximately 3 times;

Figure 27 represents a microphotograph of a fabric according to the present invention enlarged about 25 times;

Figure 28 represents a microphotograph of an area of a fabric tie loop according to the present invention enlarged about 50 times;

Figure 29 represents a photomicrograph of a tissue of the present invention enlarged about 20 times;

Figure 30 represents a microphotograph of an area of a bonding loop ”of the fabric of Figure 29 but magnified approximately 2.5 times more;

Fig. 31 represents a microphotograph of another variant of a fabric of the present invention enlarged 15 times in which the filament segments contain a sprain;

Figure 32 represents a microphotograph of the fabric of Figure 31 but enlarged approximately two more times;

tography of another tissue variant according to the present invention magnified about 15 times;

Figure 34 represents a microphotograph of yet another fabric variant according to the present invention enlarged about 35 times;

Fig. 35 represents a photomicrograph of a flat cross section of an interconnected joint of a fabric according to the present invention enlarged about 88 times;

Figure 36 represents a photomicrograph of a flat, straight section of an interconnected joint of a fabric produced according to the prior art, enlarged about times;

The figures from 37A to 37F correspond to micro photographs of a test tissue in sequential phases obtained by analyzing the image of the test tissue to determine the transparency characteristics of the tissue holes.

Detailed description of the drawings

Referring to the drawings, figure 1 represents a perspective view of a fabric 50 according to the present invention. As can be seen in this figure, the fabric consists of a multiplicity of bundles of filaments 51 with the aspect of threads, which develop between the joints 52 interconnecting them · These bundles of filaments and joints define a pattern of openings 53 which generically have the approximate configuration of a square. Each of these filament bundles consists of segments of filaments that have been compressed and compacted. In these filament bundles many of the filament segments are parallel to each other. As can be seen in the drawing, practically in the center of the filament bundle between * - 9 J ·>

adjacent joints, there is another intricate area 54 where the fibers tend to wrap circumferentially around the periphery of the compacted parallel filament segments. As can be seen, the bundle of filaments protrudes from the opposite sides of the circumferentially intricate zone, this configuration will hereinafter be referred to as the bond loop or the bond loop zone ”.

represents a section for producing fabrics

The schematic cross-sectional figure 2 of an apparatus according to the present invention. In this apparatus there is a movable conveyor belt 55 and placed on that belt, in order to move with the belt, there is a support component 56 that has a new topographic configuration. This support component has a multiplicity of pyramids and also has a multiplicity of openings arranged on the said topographic component, which is described in more detail below. On this topographic support component, a 57 filament web is placed. It may be a non-interwoven web consisting of carded filaments, filaments layered in the air, filaments obtained by fusion or similar type. There is a fluid system 59 on the filamentous web, this tubular distribution web 58 for the application of preferably water, to the filament web when filament supported on the topographic component * on the conveyor belt under this system. Water can be applied according to

Under the conveyor belt there is a tube with variable pressure tubular distribution.

tubular collector 60 driven by vacuum to remove the water in that area as the weft and topographic support component pass under the topographic filament topographic tubular distribution system

Water is applied to the fibrous web to moisten it and ensure that the web is not removed or displaced from its fluid position. When in operation, the steel is placed over the fiber component and this fibrous web and this fiber component pass under the tubular braid distributor support fluid support, to

- 10 on the topographic support component when submitted to any other treatment. Then, the topographic support component and the fibrous web pass under the tubular distributor a number of times »During these passages, the water pressure in the tubular distributor increases from an initial pressure of approximately 7 x 10 ^ Pa to pressures corresponding to 7 x IO * p _{a or} higher * the tubular distributor itself consists of a multiplicity of perforations varying in number between approximately 2 and 40 per centimeter. Preferably, the number of perforations in the tubular dispenser varies between 12 and 28 per centimeter. These perforations have a diameter that measures approximately 0.18 millimeters. After the filamentous web and topographic support component have passed under the tubular distributor a number of times the water supply is interrupted and the vacuum action is maintained to help it rinse the filamentous web. This web is then removed from the topographic support component and dried to provide a fabric in accordance with the description made in relation to figure 1.

Figure 3 represents an expanded perspective view of a portion of a filamentous web and a support component described in Figure 2. The filamentous web 57 is constituted practically by filaments 63 lying flat. The length of these filaments can vary from approximately 6 millimeters or less to about 38 millimeters or more. In the case of using filaments of the shortest type (including wood pulp filaments) it is convenient to mix them with longer filaments. The usable filaments can be of any known type, both artificial, natural or synthetic filaments, for example, cotton, rayon, naylon, polyester or similar filaments. The filamentous web can be formed using any of the several techniques well known in the art, for example, by carding, by air casting, by wet bedding, by melting and blowing and the like.

The critical part of the apparatus of the present invention is the topographic support component * In figure 3 there is shown a variant of the support component that allows the filamentous web to form the single fabric in accordance with the present invention * As noted , component 56 consists of rows of pyramids 61. The vertices 65 of these pyramids are aligned in two perpendicular directions. The inclined side surfaces of the pyramids will now be designated only by the term "sides" 66 and in the spaces between pyramids will now be designated only by the term valleys 67 (or uphill).

The multiplicity of perforations 68 existing throughout the support component are arranged according to a certain pattern in that support component. According to this variant there is a perforation in each valley in the center of the sides of adjacent pyramids and each corner was also defined by the meeting point of four pyramids. The perforations on the sides of the pyramids extend at least partially on the sides of the adjacent pyramids. The criticality of the topographic support component of the present invention lies in the angle that the side of the pyramid makes with the horizontal plane of that component in the support and also resides in the placement and configuration of said perforations and also with the dimensions and configuration of said valleys. * When a filamentous web is placed on top of a topographic support component of the aforementioned type and the filaments are forced to become intricate by the action of a fluid as described in relation to figure 2, a fabric is produced that unexpectedly has excellent earacteristieas of clarity and whose structure is quite regular * In addition, when using the topographic support component as described in relation to figure 3, the fabric produced has ties of union as described above. The angle that the sides of the pyramids make with the horizontal plane must be at least 55 and preferably 65 ° or higher. It turned out

that if the angle is between 65 ° and 75 °, it is especially suitable for the production of fabrics according to the present invention. In order for bonding to form or circumferentially curled intricate filamentous zones, the perforations in the topographic support component must be positioned on the sides of the pyramids * There may also be perforations in other positions, for example, in the corners of the pirtaids. The perforations in the corners of the pyramids tend to improve the intricacy in the joints and the clarity characteristics of the final fabric. This is especially effective with fabrics with a higher density. The width of the valleys at its base will allow you to control the width or dimensions of bundles of thread-like filaments between interconnected joints.

When producing the fabric as described according to figure 2, when the fluid reaches the filamentous mesh, it forces the filaments down against the surface of the valleys and compresses the filaments in the available space. Theoretical considerations lead to the admission that the fluid also causes a “swirl or circular movement as it forces the fibers downwards against the surface of the valleys. The combination of the openings on the sides of the pyramids and the forces transmitted by the fluid means that the filamentous segments are circumferentially wrapped around other filamentary segments. During the process practically all the filaments are forced downwards following the sides of the pyramids in such a way that the area of the fabric corresponding to the base of any pyramid is virtually free of fibers.

THE. figure 4 represents a nozzle diagram demonstrating the various steps of the process for the production of new fabrics and in accordance with the present invention. The first step of this process is to place a filament web over the topographic support component (rectangle 1). The filamentous weave is previously soaked or moistened when it is still in that component

- support (rectangle 2) to ensure that while it is being treated it remains on the support component · That support component on it containing the filamentous web passes under nozzles that emit a jet of fluid under high pressure (rectangle 3) · The preferred fluid is water. This water is then removed from the support component, preferably using a vacuum system (rectangle 4). Next, the filamentous weft is wiped (rectangle 5), the wiped pitchfork 2 is removed from the support component (rectangle 6). Then the fabric so formed is passed over a series of drying drums to obtain a dry fabric (rectangle 7). The fabric can then be finished or possibly subjected to any type of processing desired (rectangle 8). Figure 5 is a schematic representation of a type of apparatus for carrying out the process and for producing the fabrics according to the present invention. In this apparatus there is a foraminous conveyor belt 70 that moves continuously between two rotating cylinders 71 and 72 conveniently apart.

This conveyor belt is driven by a system that allows reversing the direction of its movement, that is, it can move both in the dextrogiro and senuX / levogiro directions. uu certain position of the conveyor belt, ..and precisely at the upper level 73 of the conveyor belt *, there is conveniently placed on that conveyor belt a tubular distributor 74 that adequately emits water jet · This tubular distributor has a multitude of perforations in diameter very thin, its dimensions being approximately 0.13 millimeters and there are about 12 perforations per centimeter. · Through these perforations water comes out under pressure. On top of the conveyor belt, the topographic support component 75 is placed. On top of that topographic support component, 2 filamentous webs 76 are intended to form. Directly under the tubular water dispenser, but under the upper level of the conveyor belt, there is a tubular suction manifold 77 which helps to break the water and prevent excessive soaking of the filamentous web. Water from the

tubular distributor focuses on the filaseate web passing through the topographic support component and is removed by the suction tube collector. As noted, the topographic support component on it containing the filamentous web can pass under the tubular distributor as many times as necessary to produce a fabric in accordance with the present invention »

Figure 6 shows an apparatus for continuously producing fabrics according to the present invention. This schematic representation of the apparatus comprises a conveyor belt 80 which actually serves as a topographic support component according to the present invention. This conveyor belt moves continuously in a levy-rotating direction around cylindrical components properly spaced as is known in the art. On this conveyor belt there is a tubular distributor 79 that connects a plurality of lines or groups of orifices 81 for the injection of fluid. Each of these groups has one or more rows of very fine diameter perforations, with about 12 per cent perforations and possibly more. The tubular distributor is equipped with pressure gauges 87 and control valves 88 to regulate the fluid pressure each, line c'j> group of orifices. Below each line or group of orifices there is a suction component 32 for removing excess water and for keeping the corresponding area free from any flooding. The filamentous web 83 which is intended to be transformed into fabric according to the present invention will feed the conveyor belt which in this case constitutes the topographic support component. Through a suitable needle 34 and sprinkled water on the filamentous web to pre-soak or pre-moisten said web and to help control the filaments as they pass under the tubular fluid distributors under pressure. Under this water nozzle there is a suction slit 85 to remove excess water. The filamentous weft passes under the distributor

J tubular fluid injection, with variable pressure being preferred in that tubular distributor. For exemple, the first lines of perforations or podex holes provide forces imparted by a fluid UAA próziaa pressure of 7 x 1θ5 P _ _{the £>} whereas the following rows of holes can provide forces transmitted by the fluid corresponding to UIAA pair Pressure m value close to 21 z 10 $? a and the last lines of orifices can provide forces transmitted by the fluid corresponding to a pressure of about 49 x 105 p _a> Although the figure shows six lines of fluid injector orifices, the number of lines or rows of holes is not critical, it will depend on the plot weft, the speed, the pressure values used, the number of rows of perforations existing in each line, etc. After passing between the tubular fluid injection manifold and the tubular suction manifold, the formed fabric will pass under another suction slit 36 where the excess water in the web is removed. The topographic support component may be made of relatively rigid material and may have a plurality of crosspieces.

Each crosspiece extends across the width of the conveyor belt and has a trailing edge on one side and on the opposite side has a leading edge such that the leading edge of a crosspiece meshes with the trailing edge of the adjacent crossover the movement between adjacent sleepers and also allowing this relatively rigid component to be used in the conveyor belt configuration shown in figure 6.

A preferred machine for producing fabrics according to the present invention is shown schematically in figure 7. In this machine the topographic support component is a 90 «rotating drum. The tasbor rotates in an outward direction and has a multiplicity of curved plates $ 1 which have a top-16 configuration -

desired graphic, being arranged so as to form the outer surface of the drum. Near a peripheral zone of the drum there is a tubular distributor 89 that connects using a plurality of bands with holes 92 for applying water or other fluid to the filamentous web 93 placed on the outer surface of the curved plates. Each band of holes may have water. or several rows of perforations with small suction diameters ranging from approximately 0.12 mm to 0.25 mm. There may be between 20 and 2.6 perforations per centimeter or possibly more if desired. Water or any other fluid is guided through the rows of holes. The pressure in each group of orifices increases from a first group to a last group under which the filamentous web passes. The pressure is controlled by suitable control valves 97 and pressure gauges 96. The drum is connected to a sump 94 to which a vacuum system adapts which by suction helps to remove water and keep the sound free from flooding. When the entire system is in operation, the filamentous web 93 is placed on topographic support components 91 before the tubular distributor 39 that emits water jets. The filamentous trough weighs under the bands of holes * transformed into a fabric in accordance with the present invention. The fabric thus formed then passes over a section of the topographic support component and drum 95 where there are no orifice bands but the action of the applied vacuum continues to be felt. After being dried, the fabric is removed from the drum and passed around a series of drying rollers 96 to dry the fabric.

Figures 8 to 19 represent various cross-sectional views of projections on the plan of various topographic support components that> 3 can be used in accordance with the present invention. In these figures there are several configurations of pyramids and opening patterns that can be used in the topographic support component.

Δ figure 8 is uue. cross section of the topographic support component shown in figure 3 and figure 9 represents a projection and plan of the same component. The component of the support shown in figures S and 9 produces a fabric, which corresponds to the description made in relation to figure 1. As shown in figure 9, the base of © pyramids 61 is of square section. The pyramids have a uniform nature with each of their side faces 66 an isasceles triangle · These side faces of the pyramids intersect at a point or vertex 65 with these vertices aligned in two perpendicular directions ♦ The bases of the pyramids confina® practically one with the others in such a way that the valleys formed 67 have a practically negligible width between the lateral faces of the believed pyramids. The angle ^M a ”that the lateral phase of a pyramid makes with the horizontal plane is approximately 70 ^o » the topographic support component also has opening 68 existing on the lateral faces of the. pyramids and also in the corners of these pyramids as shown in the figures. The openings in the pyramid side faces extend through those side faces of the pyramids as shown in figure 8.

Figures 10 and 11 represent another topographic support component that can be used in accordance with the present invention. Figure 1 represents a cross section and Figure 11 represents a plan view. The pyramids 100 have practically the same configuration and are arranged according to the same type of alignment represented in figures 8 and 9. However, the spacing between the lateral faces of the pyramids for the formation of valley 101 is much higher, so the openings 102 existing in the topographic support component does not extend over the lateral faces of these pyramids · The configuration shown in figures 10 and 11 can be used with filamentous threads of a denser type once there is more space for compacting the filaments between the lateral faces of the pyramids.

Figures 12 and 13 also represent a variant of a topographic support component according to the present invention. In this variant, the lateral faces of the pyramids 104 intersect the horizontal plane at different angles * The portion 105 of the lateral phase of the pyramid intersects the valley 106 making the horizontal plane an angle of approximately 80 °. The portion 107 intersects the interior portion at the apex of pyramid 108 and makes the horizontal plane an angle of approximately 55 °. The advantage of this type of pyramid configuration lies in the fact that it is easier to remove the fabric thus formed from the topographic support component. In this variant the openings 109 are arranged on the side faces of the pyramids and the openings 110 are arranged on the corners formed by the intersection of four pyramids. Still according to this variant the openings on the side faces of the pyramids are slightly larger than the openings in the corners.

Figures 14 and 15 represent yet another variant of a topographic support component in accordance with the present invention. In this type of variant the side faces of the pyramids are not uniform. The trailing edge 113 of each pyramid is practically vertical whereas the leading edge 114 of each pyramid makes the horizontal plane an angle of approximately 70 °. The support member has openings 116 as shown. By changing the configuration of the pyramids as described above, it is possible to control the forces transmitted by the fluids that fall on the filaments, so that in the valleys 115 existing between the pyramids, a higher rotational action occurs *

Figure 16 represents a plan view of a topographic support component in accordance with the present invention and Figure 17 represents a cross section taken along line 17-17 of * 19 -

figure 16. According to this variant the side faces of the pyramids 120 are the same, making each of them with an horizontal plane an angle of about 70¾ There are two openings 121 in each side phase of each pyramid * The existence of two openings in each phase side of the pyramid allows for the eventual formation of a multiplicity of ¹ * connection loops between adjacent interconnected unions in the final fabric *

Figures 18 and 19 represent plan views of preferred variants of the topographic support components of the present invention. In any of these figures, the pyramids have four side faces and have a uniform configuration. Figure 18 shows an opening 126 placed or disposed adjacent to each side phase of the pyramids. Figure 19 shows the openings 128 on the side faces of the pyramids * There are also openings 129 in the corners formed by the intersection of four pyramids. The openings on the side faces of the pyramids are slightly larger in diameter than the openings on the corners of the pyramids.

Any topographic support component according to the present invention can be made from diversified materials such as plastic products, metals and the like. The materials used must practically not be deformable under the impact of fluid that reaches its surface. The surface of the support component must be free of burrs or other imperfections, and must be a relatively smooth surface. It is preferable that this support component is not a highly polished surface since it is assumed that a surface that has some friction parameters and is desirable for the production of fabrics according to the present invention * Machined surfaces have been found to be especially suitable for the production of fabrics according to the present invention.

In all cases, the topographic support component has a multiplicity of openings arranged according to one. predetermined pattern and also has a multiplicity of pyramids with both a square section base and a triangular section base * making? the lateral faces of the pyramids with the horizontal plane an angle of at least 55 ° and preferably an angle between 60 ° _and 75 ^to 75 °. It is preferable that the openings in the plate continue through the lateral faces of the pyramids although this is not absolutely necessary but it is admitted that if so, it is easier to obtain the desired compaction between the filaments that. if you want to intricate · Please note that not all the perforations or openings in the support component need to develop completely through the support component. It is enough that at least some of the perforations develop only partially through the support component, as long as they have a sufficient depth to reduce or avoid the undesirable fluid backflow · If there is a lot of fluid backflow or some fluid driven by a very large force on the filament rearrangement zone this can cause the desired filament rearrangement to disrupt.

Figures 20 and 23 represent microphotographs of a fabric according to the present invention. The fabric is made of filaments of * rayoã ^w and has a density corresponding to 600 grains, these filaments being 1.5 denier and having a length of 32 millimeters »The fabric was made on a plate similar to that shown in figure 3, with perforations existing on the lateral faces of the pyramids with a slightly larger diameter than the perforations on the corners of the pyramids * The plate had pyramids whose base was square in section and in which the angle between the lateral faces and the horizontal plane was approximately 75 °. Figure 20 represents a plan view of the tissue, taken at a magnification of 20 times *

As can be seen, the portions of the filaments of the fabric are very dense and compacted while the open area is relatively free from filamentous ends and is well defined and sharp * The fabric is made up of a multiplicity of 200-thread-like filament groups » These groups are interconnected in joints 201 by filaments common to a multiplicity of groups and define a regular pattern of openings of square section * Between interconnected joints there are zones of connection loops 202 »

Fig. 21 represents the tissue of Fig. 20 amplified 76 times and shows one of the groups of filaments or bonding zones of the tissue. As observed »approximately in the center of this group of filaments» there are segments of filaments that are wrapped around at least a part of the periphery of the parallel and strongly compacted filament segments that constitute this group of filaments similar to a thread, that is, a bonding loop * Figure 22 represents an amplification of one of the joints of the fabric represented in figure 20. This union is constituted by a multiplicity of filament segments, some of which are practically linear through the union while other segments are they curve almost 90 ° inside the structure and there are still other segments arranged diagonally in the region that cross the union.

Figure 23 is a cross section of a fabric tie shown in Figures 20 and 21. The nearly parallel filament segments penetrate and in some cases pass through the area of the tie loops. In addition, there are also segments of filaments in the area of the connecting loops that are circumferentially wound around the filament-like filament group *

The following describes four specific examples of a method for the production of fabrics according to the present invention.

EXAMPLE 1

An identical device shown in figure 2 was used to produce the fabric * According to the method described in U.S. Patent No. ² 4475271, a uniformly carded fibrous web with a density of 300 grains and 1.5 denier consisting of filaments was produced rayon ”with a length corresponding to 32 millimeters. This weft was placed on a plate supported by a metallic mesh conveyor belt. This 12 x 10 metallic belt is smooth and consists of polyester-coated metal monofilaments and is supplied by Appleton Uire Líorlcs ”from Appleton, Fosisconsin * A Conveyor belt has 2 mm diameter long and transversal wires and an open area corresponding to 44%. The forming plate has a profile as shown in figure 12. The side face of the valley (105) of a pyramid is at an angle of 74o. with the horizontal plane and the opposite face that intersects that at the apex (107) makes an angle of 56 ° with the horizontal plane. The distance measured vertically from the base on the part corresponding to the side face 105 to the apex of the pyramid 108 is 1.14 millimeters and the vertical distance from the bottom of the valley 106 to the apex of the pyramid 108 is 2.29 millimeters. The radius of curvature of the bottom of each valley corresponds to 0 * 076 mm * The pyramids are arranged in a pattern corresponding to squares with the dimensions of 12 x 12 as shown in figure 13 * 0 spacing between the central points of the bases of each pyramid is 2 * 1 millimeter * The perforations on the sides of the pyramids have a diameter of 0.8 and the perforations on the corners of the pyramids have a diameter corresponding to 0 * 64 mm, the tubular distributor has about 11 * 8 perforations per centimeter (approximately 12) each of these holes having a diameter of 0.18 millimeters * The filamentous web placed on the plate passes over the tubular distributor and is moistened with water that positions the web in the forming component. The tickets

Subsequent strokes are carried out under pressures of 7 x 10 ^ p _3j 42 x 10 ^ Pa and finally three passes at 7 x 10 ^ p _a . All passes are made at a speed of about 9.1 meters per minute and at a vacuum pressure corresponding to 61 centimeters of water. Figures 24, 25 and 26 represent microphotographs of the resulting fabric * Figure 24 is a microphotograph of the plan projection of the fabric produced at 25 times magnification * Θ The fabric consists of a multiplicity of bundles or groups of filaments 205 with the appearance of strands * These bundles are interconnected at joints 206 by filaments common to a multiplicity of bundles so as to form a pattern of practically square openings 207. In the center of each bundle there is an intricate area (spleen) 208 and from of this intricate area the bundle would develop in opposite directions * The enlargement of figure 25 allows a clearer visualization since it corresponds to a 70 times magnification of an area of a bond '' of the fabric represented in figure 24, being the area intricate constituted. by a multiplicity of filament segments that are intertwined and intricate which extend along a part of the periphery of the bundle in order to keep the filaments very strongly compacted * Figure 26 is a 70-fold amplification of one of the interconnected joints of the fabric of this example * Some of the segments of the filaments pass directly through the joint while other segments of filaments are curved in that same joint at an angle of 90 °, with still other parts of the filaments that are intertwined and strongly intricate with the joint.

The resulting fabric was tested to determine the Calculated Density for the Yarns and to determine the Clarity Index as described below * The Calculated Density for the Fabric Yarns corresponds to 0 * 192 g / cm ^ and the Clarity Index of the fabric corresponds to the value of

1,119 *

EXAMPLE 2

A fabric was produced with the apparatus described above in example 1. All conditions and parameters are the same except that the density of the starting wefts corresponds to 1700 grains per square meter. In this process, after a pressure passage of 7 x 10 ⁵ p _a and a pressure passage of 42 x 10 ^ p _a? the web was exposed to nine passages under pressure. approximately 7 x 10θ Pa. Figure 27 represents a microphotograph of the plan view of the resulting tissue. As can be seen * although this fabric is about 5 times heavier than the fabric shown in figure 24, it still has extreme clarity and the portions of the filaments are very dense and very compact. The fabric is made up of groups of filament segments in which these filament segments are generally parallel and strongly compacted. In the center of each of these groups there is an intricate area with a portion of the circumfereucialmeute filament segments wrapped around a part of the periphery of the filament group with the aspect of threads, that is, an area of the type of bonding loop ”. These groups of filaments are interconnected in the joints by filaments common to a multiplicity of groups defining a predetermined pattern of openings of practically square section. It is surprising to see that the clarity of the pattern practically does not diminish with the increase in the density of the fabric »This fact is clearly contrary to what happens in most conventional processes of intricate or producing non-woven fabrics since in these processes, as which increases the density of the fabric, the clarity of the fabric pattern deteriorates rather quickly *

The fabric of this example was tested to determine the calculated density for the yarns and the. clarity index as described below * The density calculated for the yarns in the case of this fabric was 0.256 g / cm ^ of the clarity of the fabric corresponds to the value of 0.426.

and the index

Figure 28 represents a microphotograph of a 50-fold magnification of another variant of an area of a "fabric tie loop" according to the present invention. In this variant, the topographic support component is used to produce the fabric as previously described in relation to figure 16. There are two intricate areas in each of the yarn-like filament groups, each of these intricate areas being replaced by a multiplicity of segments of filaments that are circumferentially wound around a portion of the periphery of the parallel filament segments and tightly compacted within each of the yarn-like filament groups »

Figures 29 and 30 show yet another variant of a fabric according to the present invention. Figure 29 represents a plan view corresponding to a 20-fold amplification of a fabric made from a filamentous weave with a corresponding density. to 600 grains in which the filaments are 1.5 denier and whose length of these rayon filaments corresponds to approximately 31.5 millimeters. The filament weave was processed in accordance with the present invention using a topographic support component similar to that shown in figures 10 and 11 except that the perforations are relatively longer, so they take on the aspect of cracks narrower than the characteristic circular appearance * These slits are uniformly wide and round at their ends * These slits are long enough to develop along the valley floor from the center of the sides between two pyramids and through a intersection to the center of the sides of adjacent pyramids. Figure 29 shows a fabric made up of a multiplicity of groups of - 26

thread-like filaments in which the filament segments are relatively parallel and compacted. The groups are interconnected in filament unions that are common to a multiplicity of groups in order to form a predetermined pattern of openings of square and chamfered section »As can be seen more clearly in the micrograph of figure 30 which is a 50-fold amplification of one of the yarn-like filament groups, that yarn-like filament group gradually decreases in thickness as it moves from an interconnected joint to another adjacent interconnected joint »In general, at the midpoint of this group of filaments with the yarn aspect exists in the highly intricate area which includes some filament segments. which are circumferentially wound around a part of the periphery of the filament group with the thread aspect. As can be seen in this microphotography, in the thin section of the filament group with the aspect of yarn in which the section is decreasing, many of the segments of the filaments are practically parallel to one or more of the segments of the adjacent filaments, whereas there widest part of this variable thickness zone, the outer periphery of this variable thickness part comprises filament segments placed in parallel at the same time as the inner part of that same periphery constitutes an intricate area »The narrower (rather dense) areas of similar filament groups threads are made up of a structure of fine capillaries and provide the fabric with a fast absorbency regime »The wider part (less dense) provides a structure of larger capillaries that allows a high absorbent capacity. In this way it is possible to vary and adjust the absorbent properties of the fabric.

As noted, one of the things that provides excellent resistance to woven or knotted fabrics is the fact that the yarn produced from the filaments is twisted »How it is evident that this compacts the yarn filaments in some way and puts them in close contact increasing friction intrigue between fibers »w 27 *

When the yarn is stretched or pulled, this friction intrigue increases the yarn strength * In some variants of the fabric of the present invention it is possible to achieve a twist in the groups of yarn-like fibers that develop between joints * In figure 31 and figure 32 a fabric of the present invention is shown in which the filament segments between interconnected joints have been twisted * Figure 32 represents an enlarged part of the fabric of figure 31. In both figures the fabric was photographed while it was still on the forming plate *

The following describes a specific example of a method for producing a fabric according to the present invention in which the filament segments are twisted between interconnected joints *

EXAMPLE 3

The procedural parameters, the

The conditions and equipment used in this example are the same as in the previous examples with the exception that the initial weave has an approximate density corresponding to 330 grains per square meter of bleached cotton filaments having a micrometry of 4 * 8, an average length of 23 millimeters and a resistance of 22 grams per tex * The forming component has a pattern of 12 x 12 pyramids arranged in a square configuration * Each pyramid has a vertical height corresponding to 3 * 9 mm measured from the bottom of the valley to the apex of the pyramid * The lateral faces of each pyramid make an angle of 75 ° with the horizontal plane * The bottom of the valley has a width of 0.15 mm * The perforations are located in the corners of the pyramids and are 1 mm in diameter * The process consists of making a passage at about 1.4 x 10 ^ Pa in the absence of any vacuum action and then sequentially passage at 7 x 10 ⁵ _a passage at 4 * 2 x 10 ^ô Pa and three passages at 7 x 10 & Pa for a vacuum pressure

corresponding to Õ3.5 centimeters of water * Figure 33 is a raicrophotography of the projection of the plant with a 15-fold amplification of the resulting tissue observing the twists between intersections similar to those of the threads * The tissue in this example was tested for density determination calculated for the threads and for the determination of the index of clarity as described below. The calculated density for the yarns for the fabric in question was 0.142 g / cm3 and the index of clarity was 1.080 «

Although all the previous tissues were made with topographic plates in which square-based pyramids were used, in figure 34 there is a microphotography with a 15-fold magnification of a fabric that was made using a topographic plate in which the pyramids had triangular base instead of square base. In the present case, the fabric has three axes instead of the usual two axes. This fact gives the product very different and unusual stress properties observed in three directions * This configuration reduces the elasticity of the fabric. As shown in figure 34, each joint has six groups of thread-like filaments emanating from the joint. Any of the yarn-like filament groups has an intricacy area where at least some segments of filaments are wrapped around a periphery of the yarn-like filament group.

It is interesting to note that in the joints of the fabrics according to the present invention the filaments are extremely compact and of uniform density. Some segments of filaments pass directly through the joint whereas other segments of filaments are curved at right angles when they pass through the joint, and there are still other segments of filaments that pass through the Z plane of the joint, squeezing it and forming a very intricate area . Figures 35 and 36 are micrographs of the cross section with an enlargement of 88 times. The figure

represents a photomicrograph of a joint of a fabric according to the present invention · This fabric is made of a uniformly carded rayon filament weave with an approximate density of 400 grains per square meter in which said filaments are 1 » 5 denier and have an average length of 38 mm the formation plate corresponds to a square configuration pattern of 12 x 12 pyramids whose centers are approximately 2.1 mm apart and in which the lateral faces make an angle of 75 ° with the horizontal plane · As perforations existing at the midpoint of the lateral faces of the pyramids have a diameter of approximately 0.8 mm. The perforations in the front of the pyramids have a diameter of approximately 0.6 millimeters. The holes, the support belt, etc., are identical to those described in relation to the previous examples. The process consists of making a pressure passage of 7 x 10 ^ Pa, another pressure passage of 4.2 x 10θ p _a and three pressure passages of 7 x 10 ^ Pa, using in all cases a vacuum action corresponding to the pressure of 63.5 centimeters of water. The microphotography shows the filament segments arranged in parallel developing through the joint and the filament segments that are curved at 90 ° through the joint. It also shows a large number of filament segments that pass through the Z plane of the joint, all forming together the highly intricate joint. In contrast to all of this, figure 36 shows a joining of a fabric manufactured in accordance with the prior art * This fabric was manufactured as described in United States patent 3485706 * The forming component is a polyester filament band of square warp with a 12 x 12 distribution »The weft is a uniform 1.5 denier carding type with rayon filaments having an average length of approximately 38 millimeters * The density of this weft is approximately 440 grains per square meter. The first tubular distributor works at 7 x IO ⁵ Pa, the second tubular distributor works at 4 * 2 x 1 $ Pa and the third,

fourth and fifth dispensers operate at 7 x 10 ^ Pa »In each of these dispensers the vacuum corresponding to a pressure 63 * 5 cm of water was used. As noted, there is some intricacy in the joint and some segments of filaments are arranged in parallel * However, the joint is by no means so compacted and densified and there is considerably more randomness in the arrangement of the filaments of this joint than in the joints of the fabrics of the present invention. As concluded by observing the microphotographs corresponding to figures 20 to 34, the fabrics of the present invention have unique structural characteristics * These characteristics reside in the fact that the filamentous areas of the fabrics are very dense and compacted, on a much larger scale compared to non-woven fabrics. woven from the prior art. The density or solidity is uniform in the filament groups and is similar to that which occurs in the yarns obtained by spinning identical filaments of similar denier. Another unique feature that is observed in all fabrics of the present invention is the degree of clarity of the open areas of these fabrics * There are few terminal loops or filamentary segments that penetrate the open areas to reduce the clarity of the fabric. This property makes the resulting fabric resemble woven fabrics * In addition, the interconnected areas of these fabrics are not dilated as with the fabrics of the prior art * This fact also contributes to the woven aspect of the fabrics of the present invention. These structural characteristics allow the development of highly improved physical properties in all final fabrics. The fabrics of the present invention have good strength. In addition, the fabrics of the present invention can have both controlled and simultaneously good absorbent characteristics, especially with regard to the characteristics of twisting *

EXAMPLE 4

The following describes another

- example of a fabric variant according to the present invention. A bleached cotton weave was produced using the method described by Lovgren et al., In US patent N ⁹ 4475271. The density of the weave corresponding to approximately 580 grains per square meter is with a 5 * 0 micrometry, having these filaments of bleached cotton an average length of approximately 25.4 mm. The initial weave is supported by a flat-woven polyester monofilament forming belt in the 103 x 88 (nominal value 100) configuration obtained from ** Appleton Wire, Portland, Tennessee. The forming belt has metal warp threads with a diameter of 0.15 mm, metal closure threads with a closing diameter of 0.15 mm and an open area corresponding to the value of 17.4% of the total area * 0 tubular fluid injection distributor it is associated and consists of ten rows of holes * There are approximately 11.8 holes per centimeter in each row with each hole having a diameter of approximately 0.18 millimeters. The rows of holes are separated by a distance corresponding to approximately 51 millimeters. The filamentous web is placed on the forming belt, moistened with water to allow the web to be positioned on the belt and passed over the tubular fluid injection dispenser at a speed of approximately 91.4 meters per minute. The holes in the first row provide water at an approximate pressure of 7 x 10> Pa, the holes in the next row provide water at an approximate pressure of 2.8 x 10 ° Pa and the holes in the last eight rows provide water at an approximate pressure of 5.6 x 10 ^ Pa. There is a tubular suction distributor placed under the forming belt and under the tubular fluid injection distributor which ensures a vacuum action corresponding to 63 * 5 centimeters of water. The formed fabric is returned and the second side is formed, i.e. the side of the weft in contact with the forming belt during the first processing step is now subjected to water injected in a second processing step * second step, the fabric formed over a second

forming surface »The second forming surface consists of rows of pyramids in such a way that the vertices of these pyramids are aligned in two perpendicular directions. Each pyramid has a base with a rectangular section. On average, there are approximately 3 * 15 pyramids per centimeter in the machine direction and about 7.75 pyramids per centimeter in the transversal direction. The base of the pyramid is approximately 31.3 mm long in the machine direction and approximately 1.27 mm wide in the transverse direction. The base of the valley between pyramids has a circular cross-section with a radius of curvature of approximately 0.076 mm e. the height of each pyramid measured from its apex to the said valley corresponds to approximately 1.65 millimeters. The perforations are arranged on the forming surface according to a regular pattern, that is, in the valleys in the center of the larger sides of adjacent pyramids and at the point of intersection of four pyramids. Each perforation has a diameter of approximately 0.84 mm. The tubular fluid injection dispenser associated with the second forming surface has nine rows of holes »There are approximately 11 * 8 holes per centimeter, in each row each hole having a diameter of approximately 0 * 18 millimeters * After forming the weft, moisten with water and passed under the tubular fluid injection dispenser at a speed of approximately 91 * 4 meters per minute »The holes in the first row provide water at a pressure of 2.8 x 10θ Pa and the holes in the last eight rows provide water at an approximate pressure of 11 * 2 X 10 ^ Pa. There is a tubular suction collector under the second forming surface that allows maintaining a vacuum action corresponding to 63 * 5 centimeters of water. The resulting tissue thus formed. it has a calculated density for strands whose average value corresponds to 0 * 154 grams per cubic centimeter and an index of clarity corresponding to the value 0 * 66 when subjected to a test as described below *

DETERMINATION OF THE CLARITY INDEX

The analysis is described below by. images specified for the determination of the clarity index of perforated non-woven fabrics * The clarity index measure is measured in perforated non-woven fabrics that do not contain any binder. The clarity of a perforated fabric without any binder is a function of the distribution of the filaments in a fabric, increasing this index of clarity as a larger portion of filaments is placed in different areas covered by the filaments surrounding the holes in the fabric. In order to determine the index of clarity of a fabric without binders and with holes, several fractions from different areas are measured · The quantity of filament coverage (CF) is the fraction of area that represents, for example, gauze threads woven or different bundles of fabric filaments not interwoven with holes · The filament size in the openings (or holes) (EA) is the fraction of area that represents the filaments that are not part of the bundles of the filaments but that penetrate the open spaces, for example example, between woven gauze threads or that penetrate the holes or openings of non-woven fabrics. The magnitude of the area of the openings with clarity (AC) represents the fraction of the area of the openings or holes in the tissue | is the sum of the fraction of the area corresponding to the open area (AA) and the fraction of the area corresponding to the AF | » The index of clarity (IG) of a fabric with holes is calculated as the ratio between the fraction of the area of the openings with clarity (AC) and the sum of the large filaments in the openings (EA) and coverage by filaments (CF) represented by next expression;

IC - AC / (FA. * CF) resulting Clarity index increases with the clarity of tissue formation with holes · Clarity index of tissues with holes can be measured using image analysis * Essentially, image analysis implies the use of computers that allow the calculation and processing of the numerical information provided by the images * The image of the tissue is obtained using a microscope with an amplification in order to reproduce the same pattern several times on the screen at the same time as the visualization of existing individual filaments on the tissue * The optical image of the tissue is formed by a great lens placed on a video camera and transformed into an electronic signal. Suitable for analysis * The microscope uses a stabilized light source that is transmitted in order to produce an image on the monitor with a visual contrast such that the areas covered by filaments have different shades from gray to black and in such a way that the open or filament-free areas are white * Each line of the image is divided into sampling points or pixels for measurement. The magnitude of the average opening area can also be determined by analyzing images in the form of the average value of the individual areas, usually in square millimeters, this value representing this value the openings involved by areas covered with filaments identified as being the area corresponding to the magnitude. fiber coverage (CF) *

These analyzes are carried out using a Leica Quantimet Q520 image analyzer equipped with the option of storing shades of gray and with the computer application in version 4 * 02, all of which can be obtained from leica, Inc. of Deerfield, Illinois, USA . The optical microscope using is an “Olympus SZH” microscope with 10 times magnification using a 0 »5X lens and a 20X eyepiece» This microscope is equipped with a stabilized transmitted light source * A “Cohu Model 4812 video camera provides the connection between the microscope and the image analyzer *

It is considered adequate as an element

a commercially available woven gauze fabric with U * S »P« type VII features for comparison on the image analyzer. The woven gauze package is opened, a single sponge is removed and unfolded until a layer of elementary thickness is obtained * Place the woven gauze layer between two clean glass slides on the microscope stage and look for to get a very vivid image on the video screen. Orient the tissue pattern so that it is possible to see it repeatedly on the screen * See figure 37A * Using the Leica Quantimet Q520 image analyzer configured with the Olympus SZH microscope, with an established amplification as described before , an analyzer calibration corresponding to 0.021 mm / pixel is achieved and it is possible to analyze an area containing between 14 and 24 repetitions of the integral USP gauze pattern type VII in the single optical field. The brightness and contrast of the image (gain and compensation) are determined to encompass the full scale of gray levels in the displayed image (a visual representation of the gray level histogram contains all possible gray levels on the scale). A procedure of this type allows the detection of the threads, the areas of clear or unimpeded openings and allows the detection of the filaments that extend from the threads reaching the orifice areas. Then the sample is removed from the microscope stage and the two clean glass slides are used to perform a tonal correction in order to eliminate the effects of any diffused light that passes through the optical field. Then the sample is placed on the microscope stage again.

To measure the index of clarity, several operations for obtaining images are performed as described below:

. First, the level of detection of the black area of the image is adjusted so that it is equal only to the bundled filament yarns and to the interconnected unions without detecting the individual filaments that leave the wires and penetrate the openings.

ras. See figure 37S. The gray level is recorded in the black detection for future reference.

2. Using the “Amend function, the corresponding detected image of wires in the detected plane 1 is stored in plane 3 for measurement at a later time. This image on the image plane 3 represents the fiber coverage area (CF). See figure 37C. Note: if necessary, to fully detect the filament coverage area, the image in plane 1 is expanded a certain number of cycles until the perforations contained in the filament coverage area are eliminated; then the image is blurred the same number of cycles to return the edges of the coverage area by filaments to their original limits as specified in the detection menu.

3 »Next, the level of white detection is established so that it is equal to the areas that are free of filaments inside each opening contained in the optical field, the level of white detection for future reference is also recorded. This image detected in the image plane 1 represents the open area (AA) of the tissue. See figure 37D.

4. Using the Logical function, the images in plane 1 and plane 3 are combined according to the following expression: Invert (Plane 1 XOR Plane 3). This means that an image is created of all pixels that are neither in plane 1 nor in plane 3. This operation generates an image in plane 4 of the filaments that come out of the threads and penetrate the fabric openings or filaments in the openings ( AND THE). See * figure 37E.

5. The following measurements of the image field and the values of the area fraction recorded are performed for the calculation of the clarity index;

- 37 -

Plan 1 (AA) (Figure 37D) Plan 3 (CF) (Figure 37C) Plan 4 (FA) (Figure 37E)

The fraction of the area of the openings is calculated clearly or exempt (AC) by determining the sum of the open area (AA) and the filament in the openings (FA). The clarity index (CI) is also calculated by determining the quotient between the magnitude of the area of openings with clarity (AC) and the sum of the two fractions of areas, that is, the magnitude of the filaments in the openings (FA) and coverage of filaments (CF):

IC = AC / (FA + CF)

Other woven gauze fields are measured by an identical process using the black detection level and the white detection level chosen in steps 1 and 3. The results of several representative areas of the fabric are averaged (for each fabric analyzed at least ten fields) to obtain the average clarity index.

Image analysis is also used to determine the dimensions of the openings by specifying the area of an average opening in square millimeters. For each field examined in steps 1 to 5, proceed as described below in the remaining steps after having recorded the field measurements and before moving the tissue to the next field:

6. Using the Logical function again, the images in plane 1 (AA) and plane 4 (FA) are combined (Figure 37E) using the image addition function (OS) to form an image of the area fraction of clear or exempt openings (AC) in plane 5. See figure 37F · The image equation is as follows:

Plan 5 (AC)

7.

8.

9.

The characteristics measurement menu establishes the parameters for measuring plan 5 (AC) *

In the histogram menu, the area parameters are selected and marked by graphic selection * Then select the Measure function to analyze the image of the plane 5 (AC) for the areas with individual characteristics »

Repeating steps 6 to 8 for each field after the analysis performed for the clarity index (steps 1 to 5 described above) will generate a cumulative histogram of AC areas with the corresponding mean and standard deviation values (the histogram does not has clarity between the different fields of the same tissue sample) *

10 * At the end of the series of fields for the woven gauze fabric, the average of the area of openings and the standard deviation specified in square millimeters is recorded * index of clarity and the average opening area for the fabrics according to the present invention and for fabrics according to the prior art are analyzed by a similar process using the detection levels determined during the analysis of the woven gauze * For the Clarity index, field measurements are stored and calculation of results, for example, using the Lotus 1-2-3 spreadsheet * The index of clarity for each fabric represents the average index of clarity * After the accumulation of parametric data for each field, the average value and the standard deviation in the spreadsheet, this value being called the average opening area * The fabrics of the present invention have a clarity index, measured as described above, corresponding to the value or 0 * 5 or higher. The most desired fabrics of the present invention have a lightness index corresponding to the value 0 * 6 or higher whereas

Preferred fabrics of the present invention have a Clarity Index corresponding to the value 0 * 75 or higher *

DETERMINATION OF THE CALCULATED DENSITY FOR THE YARNS term density calculated for the yarns refers to the density of the yarns. bundles of filaments in the fabric without binder and with holes. The density density calculated for the threads is determined from the fraction of area that represents the area of the filament covered pattern and from a density of the fabric calculated using the mass of the fabric in grams per square centimeter divided by the average thickness, in centimeters, of bundles of filaments. The measurements for determining the calculated density for the yarns are carried out on non-woven fabrics without binder * The method for determining the calculated density for the yarns, which is expressed in grams per cubic centimeter, for fabrics is described below. not woven with holes *

This analysis requires determining the tissue mass (M) in grams per square centimeter (g / cm2), measuring the thickness (Z) of the filament bundles in centimeters (cm) and analyzing the clarity index to provide the fraction of area (CF) representing the area of the pattern covered by filaments *

A standard test method such as ASTM D-3776 is used to determine the mass of a tissue. The thickness of the filament bundles can be determined using a Leica Quantimet Q520 image analyzer that allows the measurement of cross sections of the filament bundles * To prepare a fabric for the corresponding image analysis of the embedded filament bundle thickness. a representative sample of the fabric is made of a transparent resin (Araldite MG type resin) and cross sections of the block made up of the * 40 fabric / resin are performed using a low speed saw such as a Buehler Isomet San type saw equipped with a dialy. A series of cross sections is cut each 0.27 mm thick both in the machine direction and in the fabric's cross direction and is mounted on microscope slides using the mounting medium, for example, Norland Optical Adhesive 60. From the microscope examination of the series of sections by comparison with the original tissue piece to be analyzed, the cross sections representative of the filament bundles are marked for measurement purposes. The sections of the filament bundles of the nonwoven fabric are selected with the cut made in the region located approximately in the middle zone between the joint loop configuration and an interconnected joint or, if there is no union loop configuration, between two interconnected unions »The sections of the filament bundles in non-woven fabrics of the prior art are selected by making the cut approximately in the middle zone located between interconnected unions.

The thickness of each selected filament bundle is identified as being a length of a line drawn across the cross section from the border region that represents a fabric surface to the border region that represents the opposite surface. The length of the lines that represent the thickness of each bundle of yarn is measured and the average value of the thickness (2) of the bundle of yarn is recorded in centimeters. the area fraction (CF) that represents the area covered by the filaments for the sample is obtained from the analysis of the clarity index »

Following determines the magnitude calculated density for the yarn in grams per cubic centimeter (g / cni ^) _EIA according to the following expression:

Density calculated for the wires = M / (Z * CF)

DETERMINATION OF THE TISSUE DENSITY A method for determining the density of the fabric for a type of non-woven fabric with holes is described below. The density of the fabric is a quantity calculated from the mass of the fabric. Per unit area in grams per square centimeter, from the thickness of the fabric in centimeters and a. from the fraction of area that represents the corresponding area of woven pattern covered in filaments. The high tissue density is specified in grams per cubic centimeter.

Standardized test methods (for example, according to ASTM D-1777 and D3776) are used to measure mass per unit area and thickness. The density of the fabric is then calculated by dividing the mass per unit area by the thickness and this quantity is expressed in grams per cubic centimeter »The fraction of area that represents the area of the pattern covered in filaments in the fabric corresponds to the value of the covering quantity by filaments (CF) obtained from the analysis of the clarity index. See the previous description. Next, the density of the tissue is calculated by dividing the tissue specific mass by the area fraction (CF).

The fabrics of the present invention have a calculated density for the threads, measured as previously described, of at least 0.14 grams / cubic centimeter. The most desired fabrics of the present invention have a calculated yarn density corresponding to 0 * 15 grams / cubic centimeter and higher whereas the preferred fabrics of the present invention have a calculated density for yarns of at least 0.17 grams per cubic centimeter *

Having just described the present invention with specific details and with examples that elude its practical embodiment, it is noted that for

experts in the field it is evident that numerous variants, applications, modifications and extensions of the basic principles involved are possible without departing from their spirit or scope.

Claims (1)

- 1® Non-woven fabric characterized by being constituted by a multiplicity of fibrous groups with the aspect of threads, these groups being interconnected in their joints by fibers common to a diversity of said groups to define a predetermined configuration of perforations in the fabric, these strand-like fibrous groups being constituted by a diversity of parallel and tightly compacted fibrous segments, having at least some of these strand-like fibrous groups surrounded circumferentially at least a portion of the periphery of said parallel and tightly compacted segments » - 2® non-woven fabric according to claim 1, characterized in that the circumferentially wrapped portion has fibrous segments that extend at least partially into the yarn-like fibrous groups » A non-woven fabric according to claim 1, characterized in that the circumferentially wrapped portion is arranged practically in the center of the. group of fibers between interconnected joints * Non-woven fabric according to claim 1, characterized in that the diversity of parallel and compacted fibrous segments in some groups of fibers has a helical configuration, Non-woven fabric according to claim 1, characterized in that it comprises a variety of circumferentially wrapped portions arranged between the interconnected joints. - 6® - Non-woven fabric according to claim 1, characterized in that the joints are constituted by a diversity of fibrous segments, some of which are fibrous segments of linear configuration, while others of these fibrous segments have a 90 ° fold, and there are still other fibrous segments that have a diagonal arrangement inside the joint. - y 2 * · Nonwoven fabric according to claim 6 characterized in that said joints have fibrous segments that develop in the 'Z' direction of the fabric. - ₈ ã Non-woven fabric characterized by constituting a diversity of fibers rearranged to form yarn-like fibrous groups in which the fibrous segments belonging to a group are compacted and arranged practically in parallel and constituted. also due to a diversity of highly tangled areas, interconnecting some of these tangled areas, the referred thread-like fibrous groups while others of these tangled areas are arranged in a fibrous group similar to a thread. Non-woven fabric according to claim 8 characterized in that the tangled area arranged in a thread-like fibrous group is practically centered between adjacent tangled areas that interconnect the thread-like fibrous groups. . 10 § Non-woven fabric characterized by being constituted by a diversity of fibrous groups similar to threads interconnected by joints by fibers common to a diversity of the referred groups to define a predetermined configuration of perforations, these fibrous groups being similar to threads constituted by an urn diversity of parallel fibrous segments and tightly compacted, the fibrous segments being twisted in at least some of these groups similar to threads, so the fibrous segments are arranged along a helical line when passing through the fibrous group similar to a thread * - lis Machine for producing a non-woven fabric characterized by a pre-determined configuration of perforations defined by the fibrous groups similar to threads interconnected in the joints of a layer of initial fibrous material, whose individual fibrous elements are able to move under the influence of forces applied by fluids, consisting of a support component. three-dimensional that has a specific topographic configuration to support a fibrous web, these support components having a diversity of pyramids arranged according to a certain configuration on a surface, each pyramid having a vertex and a base and a diversity of faces that extend from the apex to the base, making the faces of the pyramid an angle greater than 55 ° with the horizontal surface of the support component, these support components having a variety of openings-, these openings being arranged according to a predetermined configuration relative to those pyramids and having means to project adjacent fluid currents simultaneously against the upper part of these pyramids while the fibrous layer is disposed there. - 12.s - Machine according to claim 11, characterized in that the openings are arranged in areas where the lateral faces of the pyramids intersect said support component * - 13a - Machine according to claim 12, characterized in that the openings extend from the side faces of the pyramids * - 14® - Machine according to claim 11, characterized in that each pyramid has four side faces · » 15§ Machine according to claim 14, characterized in that the apexes of the pyramids are aligned longitudinally and transversely in relation to the support component » Machine according to claim 11, characterized by openings in the lateral faces of the pyramids and openings in the corners of the pyramids. - 17 * ~ Machine according to claim 11, characterized in that the openings have an oval configuration. - 18 to - Machine according to claim 11, characterized in that the openings have an oval configuration and extend along a portion of the lateral faces of the adjacent pyramids and through the corner four pyramids intersect. - 193 - Machine according to claim 11, characterized in that the side faces of the pyramids develop at an angle of at least 70 ° with the horizontal surface of the support component for a portion of the side face of the pyramid and then make an angle of less than 70 ° côa that horizontal surface from that portion to the apex of the pyramid. - 20 ^s - Machine according to claim 11 characterized in that the side faces of the pyramids make an angle greater than 65 ° with the horizontal surface of the support component * · 21 ^s Machine according to claim 11 characterized in that the openings are of circular configuration and have a diameter that is practically equal to the distance between the base of adjacent pyramids. - 22 s Machine to produce a non-woven fabric rearranged from an initial layer of fibrous material, whose initial fibrous elements are able to move under the influence of forces applied by fluids, characterized by being constituted by: a hollow rotating drum that it has a diversity of pyramids that develop from the outer surface of said drum, these pyramids being axially and circumferentially arranged in relation to the drum, each pyramid having a vertex and a base and a diversity of lateral faces that develop from the apex to at the base, making the lateral faces of the pyramids an angle greater than 55 ° with the surface of the drum, this drum surface having a variety of openings arranged according to a predetermined configuration, means for positioning said fibrous layer at the vertices of the pyramids on a portion- of the periphery of the drum, means located in and rear of the drum to project adjacent streams of fluids simultaneously against that fibrous layer and then against the pyramids and then through the openings and into the drum, means for rotating said drum while said fluid is being projected against said surface outside, means existing inside the drum to remove fluid from the drum surface and means to remove said rearranged fabric from the drum surface. * 233 Process to produce a non-woven fabric containing distant openings defined by groups of fibrous segments of a layer of overlapping fibers according to a random rearrangement with mutual adjustments by friction, these fibers being able to move in response to forces applied by fluids, characterized in that it consists of supporting the layer locally through the area to be affected to maintain its integrity at the same time that the layer is thus supported; move the fiber segments in that layer, laterally from the areas of the layer spaced laterally and longitudinally from another layer, causing them to come closer and that there is greater parallelism with the segments of adjacent slits existing between these remote areas, simultaneously moving the fiber segments according to a circumferential arrangement around the fiber segments that move in the direction of greater proximity and increased parallelism by applying to the approximate centers of each to immediately adjacent areas at a distance forces that have opposite lateral translation components that act in parallel to the layer plane and which cooperate with rotational force components, a portion of these rotational force components acting in the plane of the fibrous layer and parallel to that plane, while other rotational forces act in the plane of the fibrous layer and perpendicularly to that plan. - 24 § Non-woven fabric characterized by being constituted by a multiplicity of fibrous groups similar to threads, these groups being interconnected in the connections by fibers common to a diversity of said groups in order to define a pre-determined configuration of perforations in the fabric, having this fabric has a Clarity Index of at least 0.5 and a calculated Fiber Density of at least 0.14 grams per cubic centimeter »~ 49 25® Nonwoven fabric according to claim 24 characterized by o. Clarity index is at least 0.6. 26. Non-woven fabric according to claim 25, characterized in that the calculated fiber density is at least 0.15 grams per cubic centimeter. - 27- - Nonwoven fabric according to claim 24, characterized in that the Clarity index is at least 0.75. - 28 ^ _ Nonwoven fabric according to claim 27 characterized in that the calculated fiber density is at least 0.17 grams per cubic centimeter.