ES2231892T3 - TRAINED FABRICS APPEAR THREADS OF HIGH MODULE COATED MATERIALS. - Google Patents

Abstract

The present invention is directed towards yarns of covered high modulus filament materials and fabrics which are formed therefrom. The present invention is intended to provide a composite filamentary material which exhibits the advantages of high modulus materials while providing a means for compensating the diminished properties exhibited by such fibers in the direction normal to molecular chain orientation. The composite filament structure of the present invention is a high modulus filament material covered with bicomponent filaments. The composite filament structure has a first interior layer of high modulus filament material and a second exterior layer of bicomponent fibers, the second exterior layer of bicomponent fibers being covered around the first interior layer of high modulus material along its entire length. The entire surface area of the high modulus material should be covered.

Description

Fabrics formed from threads of materials High modulus coated.

Field of the Invention

The present invention is directed to tissues that comprise threads of high modulus materials, such as materials polymers, coated with a second material. The tissues are can be used in fabrics for papermaking machines and other industrial applications of fabrics.

Background of the invention

Paper machine fabric is the expression used for industrial fabrics in the forming, pressing and Drying paper machines. Generally, they are manufactured with multifilaments either polyester or polyamide and / or braided monofilaments in large conventional textile looms.  Generally, these fabrics have been manufactured using techniques Conventional weaving.

The primary function of all fabric machine Paper (TMP) is to separate the water from the sheet of paper. Like both the manufacturer of papermaking machines like the paper maker work to increase the speed of the papermaking process and improve the quality of paper, new obstacles to the tissues of TMP that demand an innovation in the materials and design of the tissues. On the other hand, the TMP manufacturer is also looking for a more efficient production of TMP fabrics and improve key quality characteristics thereof.

Today, machines for manufacturing paper are reaching speeds so fast that the thickness of the tissue structure is beginning to limit the speed of water separation, especially in the section of conformed. Insufficient dehydration results in Low blade resistance. Blade strength is critical. to transfer and maintain sheet properties through the following and more aggressive stages of dehydration of the leaf. One possible solution is to lengthen the forming section of the machine, but this is quite expensive and therefore feasible limited The other approach is for the TMP manufacturer to produce thinner fabrics, but in a weaving procedure the smallest possible dimensions are the combined diameters of the filaments used in the warp and weft directions. Criteria such as dimensional stability, resistance of tissue and tissue life result in a practical limit for the fineness of the diameter of the filament and, thus, for the overall thickness of the fabric. In many TMP applications, it is not feasible or practical a waiver of these properties and, in fact, higher machine speeds currently require a further increase of these properties.

There is a clear need for fabrics with a high strength, low weight, and relatively thinner than They are currently available.

The surface topography of TMP tissues Contributes to the quality of the paper product. Have been made efforts to create a contact surface with the sheet smoother paper. However, the surface smoothness of the tissues twisted TMP is limited by the topography resulting from the weaving pattern and the physical properties of the filament. In a braided fabric (or in a puckered fabric), the smoothness is inherently limited by the nodes formed at the points of crossing of the threads that cross.

The high modulus materials are materials potential for use in applications that require high properties Mechanical and light weight. Based on the ownership of the weight, the high modulus polymers have a clear advantage over metals and ceramic materials.

High modulus polymers are highly anisotropic, and the high modulus is only achieved in the direction of the orientation of the molecular chain. In fact, properties normal to the molecular axis have considerably more values lower than the properties presented in the longitudinal direction. Therefore, in the normal direction to the molecular axis They have low cutting and compression properties.

Design concepts are known in the art of a composite material in order to compensate for the discrepancy of properties. U.S. Patent is representative. No. 4,927,698 which describes the threads of a core of filaments resistant to fire, such as Kevlar® and Nomex®, inside a fiber cover contractable cuts such as threads that appear to be chemically bonded to the fire-resistant core through reactions between a first crosslinkable resin, a second resin crosslinkable, the Kevlar® / Nomex® component, and the cut fiber

By US Pat. No. 5,617,903, published on April 8, 1997, a fabric for manufacturers is also known of paper that is constructed from polymer fibers, with 15 per one hundred or more of the tissue fibers greater than 100 deniers, and multipolymer fibers. Multipolymer fibers contain two or more different polymer regions within their cross sections. The multipolymer fibers can be constructed as a core deck, side by side, or islands in the form of the current. Each component of the multipolymer fibers is select to provide a combination of properties not available in any single polymer fiber.

Compendium of the invention

The present invention is directed towards tissues according to claim 1, which are formed by threads of materials coated with high modulus filament. The present invention aims to provide a material filament material  compound that presents the advantages of module materials high, while providing a means to compensate for diminished properties presented by said fibers in the normal direction to the orientation of the molecular chain.

The present invention is a structure of filament of composite material in which a filament material High module is coated with two component filaments. The composite filament structure has a first inner layer of a high modulus filament material and a second outer layer of two component fibers, the second outer layer of two component fibers covering its around the first inner layer of a high modulus material to throughout its entire length. All surface area of the material High module must be coated.

The two component fibers of the present invention may be either of an arrangement of core cover or side arrangement with side, the cover-core being preferred. It is further preferred that the cover component has a point lower melting than the core component.

Suitable two component fibers include cover-core combinations of copolyester / poly (ethylene terephthalate), polyamide / poly (ethylene terephthalate), polyamide / polyamide, polyethylene / poly (ethylene terephthalate), polypropylene / poly (ethylene teref-talate), polyethylene / polyamide, polypropylene / polyamide, polyurethane thermoplastic / polyamide and polyurethane thermoplastic / poly (ethylene terephthalate).

"Module", as used here, refers to the tensile modulus defined as the slope of the linear portion initial response to elongation by load (curve of tension-elongation) of a test tube deformed to the room temperature.

The high modulus material, as used herein, includes high modulus polymers having a tensile modulus greater than about 25% of theory. Alternatively, a high modulus polymer is one that has a tensile modulus greater than about 25 GPA. Encyclopedia of Polymer Science, 2nd edition, volume 7, p. 699-722 . It should be noted that highly oriented polymer structures are anisotropic, and as the module increases by increasing the degree of orientation of the molecular chain, in other directions the module decreases proportionally.

Suitable high modulus polymers include, but they are not limited to them, aramids, such as poly (p-phenylenterephthalamide), available in Dupont under the trade name Kevlar®, other aramids such as Kermel® (available in Rhone-Poulenc), Arenka®, available in Akzo, Nomex (available in DuPont), poly (ethylene naphthalate) (PNE), poly (p-phenylenebenzobistiazole), polyesters, glass, aromatic polyamide resins, Arenka®, an aramid available in Akzo, thermotropic copolyesters such as Vectra® (Celanese) and Xydar® (Dart), high modulus polyethylene fibers such as Spectra 900 (Allied).

Skilled craftsmen should appreciate that there are several ways by which the inside of the module can be coated tall, such as braiding and wrapping. A fiber braid of two components around the inside of high module It provides a structure with good stability. Wrap the High modulus fibers with the two component fiber material is Another suitable method. The fibers can be coated well with a single coating machine or with a machine double coating. In both cases, the core fibers are Coil spirally with a selected step.

In the construction of fabrics of the present invention, you have the advantage of the unique structure of the filament of two components. The melting point of the component of the cover is less than the melting point of the core component, and less than the melting point of the high module interior. Be communicates improved structural integrity by heating the tissue, that has been formed from the threads that cross each other in the tissue, at a temperature above the melting point of the cover but less than the melting point of the core and the high module interior, and then cooling later. This procedure, referred to herein as heat fusion, causes the two-component fiber cover components enter in a softened state and, consequently, the threads melt each other at the contact points when they cool to temperatures below the melting point of the cover material. In its for the most part, such contact points are the points where threads cross each other.

Due to improved tissue stability of the present invention, it is believed that a single layer fabric constructed with the composite threads of the present invention can work successfully in a machine for the paper making That is, the present invention provides a means to produce single layer fabrics capable of resisting demanded conditions to which the fabrics of the paper machines Generally, tissues should be constructed with at least two layers, to ensure that the tissues have the dimensional stability and strength needed in order to Resist the demanded operating conditions.

The present invention can also be used as the upper stratified structure of a multilayer structure, and it is believed that its use as such a layer offers advantages over conventional materials due to the small size of the knots in the surface of the fabric and the small size of the fabric. He Small knot size creates a smoother fabric surface, a feature desired by paper manufacturers. It is also it is possible that a thinner fabric can be made using the high modulus composite yarns of the present invention, since the excellent tensile properties possessed by high modulus materials imply that less can be used material to achieve the degree of resistance possessed by conventional fabrics. The present invention can also be used as the base layer of a multilayer structure. Stability improved dimensional of this layer makes it very suitable for this use. The use of a fabric according to the invention as a base layer communicates certain advantages to the overall construction of the fabric. Market Stall that the composite threads of the present invention they have a relatively high degree of resistance throughout the thread axis, the use of this fabric layer as the base layer will provide the required stability and strength of the global structure of the tissue. Therefore, in other layers of fabric can be used less rigid materials, allowing the paper manufacturer, for example, select fine denier fibers to build other layers. Therefore in this way Thinner fabrics can also be manufactured. A fabric is desired thinner as drainage properties are improved.

Threads may be the only constituents of At least one layer of a fabric. In the case of a layered fabric multiple, at least one layer is constructed with the threads of the present invention and preferably constitutes the layer surface that is in contact with the sheet of paper. Whether the fabric is single layer as multilayer fibers two components must be arranged in an orderly manner not random Arranged in a non-random orderly way you want say that some fibers of the fabric run in a first direction, those fibers of the first direction do not intersect with other fibers that run in the first direction; and what about fabric fibers run in a second direction, those fibers of the second direction does not intersect with other fibers that run in the second address; the fibers that run in the first direction intersect with the fibers that run in the second address, and vice versa. For example, the fibers arranged in the machine direction will not cross each other and such fibers they will only cross with fibers that run in the direction transverse to the machine. Fabrics can be built with fibers that run in the directions of the machine or transverse to the machine, but such fabrics can also be built with fibers that run in directions that form a certain angle with the machine directions and transverse to the machine for the paper making

Brief description of the drawings

Figure 1 is a braided fabric of material compound of the present invention.

Figure 2 is another braided fabric of material compound of the present invention.

Figure 3 is a cross section of a wire of The present invention.

Detailed description of the preferred embodiment

Figure 1 is a fabric comprised of threads of The present invention. The fabric is a weaving construction smooth, with threads in the direction of the warp and the weft, being comprised of threads of the present invention. Figure 1 shows You can see that the wires are interconnected with other wires at the points where the threads intersect. This is attributable to the fusion of the threads by heat, in which the covers of the two component materials melt together after heat the tissue at a temperature above the melting point of the cover material, but less than the melting point of the core material.

Both warp and weft threads of the tissue shown in Figure 1 are of the same structure. He High modulus interior of the threads are approximately 134 Kevlar® 49 filaments. Around the interior of Kevlar®se twisted eight wires of two components. Each thread is constituted by sixteen (16) two component filaments. The filaments are Bellcouple® by Kanebo, denier 250, 16 filament beads that they have a temperature copolyester cover material of low melting and a core of poly (styylene terephthalate), the melting point of the copolyester cover being less than the melting point of the PTE.

The eight wires of two components are braided around the inside of Kevlar®. The braid forms a structure relatively stable, and the high modulus coated wires are They can be used to form tissues as shown in Figure 1. Such tissues are formed according to the methods easily appreciated by Those skilled in the art. After the tissue has formed, it is put under tension, it is heated to a temperature higher than the melting point of the cover, but less than the melting point of the core, and then cooled to a temperature lower than the point cover melting.

Due to improved tissue stability of the present invention, it is believed that a single layer fabric constructed with the composite threads of the present invention can work successfully in a machine for the paper making That is, the present invention provides a means to produce single layer fabrics capable of resisting demanded conditions to which the fabrics of the paper machines

Generally, tissues should be constructed with at least two layers to ensure that the tissues have the dimensional stability and strength needed in order to Resist the demanded operating conditions. With everything, because the paper machine fabrics of the present invention are characterized by low elongation and high modulus materials, the high module material layer provides the stiffness and dimensional stability of the tissue and, consequently, the tissues of a layer are possible. In other words, due to high degree of resistance provided by such materials, is possible to use less material to build a fabric while communicates equal or even greater resistance compared to multilayer materials that contain considerably more material. Getting a single layer fabric design is a breakthrough substantial in the design of TMP. As the speed of the machine, reducing the time for drainage, becomes more significant ability to achieve the smallest caliber possible, since a single layer fabric is thinner than a multilayer tissue, reducing the distance that the liquid should cross in order to drain.

The present invention can also be used as the upper stratified structure of a multilayer structure, and it is believed that its use as such a layer offers advantages over conventional materials due to the increased planarity of the surface. An increased planarity is the result of a reduced size of the knots at the points where the threads intersect. Low heat fusion of the tissue, the melting temperature component Low two-component fiber collapses and flows, reducing the knot size of the crossing points.

The present invention can also be used as the base layer of a multilayer structure. Dimensional stability Improved this layer makes it very suitable for this use. Of this mode, in other layers other materials, such as those of fine diameter, since by means of the layer built with the High modulus material communicates stability and resistance. He use of thin-diameter materials in contact layers for sheets paper will improve surface smoothness, a feature desirable of paper machine fabrics.

Figure 2 shows a fabric in which the threads described in relation to Figure 1 above are used in the warp address. The threads of the plot address They comprise a 9 layer material. That is, they are a layer of nine two component material threads as described in Figure 1. The folded threads loosely intertwine each other. The folded threads have a clearly smoothed appearance. That is to say, after heat fusion, the threads take on an appearance similar to a tape.

Figure 3 shows a cross section of a composite yarn according to the present invention. Inside of Kevlar® is visible as a different region. The exterior of two Components is not discreet.

When operating on a machine for manufacturing of paper, a fabric according to the present invention must remain longer clean than a fabric comprised of conventional monofilaments. Heat fusion of a fabric comprised of two fibers components is characterized in part by crossover threads melted On the contrary, conventional monofilaments have  interstices at the points where the threads intersect. The merger in the crossings of the two component fibers decreases, and possibly eliminates such interstices. The interstices are constriction points where remains can be trapped and accumulate over time. Therefore, crossover threads heat melts produced with two component fibers they provide a structure that must remain relatively longer clean than a fabric comprised of monofilaments conventional.

Another advantage that is believed to possess the fabrics of paper machine of the present invention, on fabrics conventional comprised of monofilaments, is that such fabrics present at the crossing points surfaces without knots and relatively flat You can easily see that when fibers are braided (or gathered), knots are formed with a smoothness Shallow diminished As noted, the size of the knot is reduces with the fusion of the two component fibers by heat, what It improves surface smoothness. The surface smoothness is a factor that affects the quality of the paper. Therefore, the Enhanced smoothness fabrics are of interest to the paper manufacturer and related products. With the heat fusion of a fabric comprised of two component fibers a network of junctions between the crossover fibers. A physical union of this kind improve dimensional stability on a conventional fabric built with monofilament. Due to the nature of the fibers of two components and the unique structures that can form, it they can use denier fibers smaller than those required for conventional monofilaments. The use of smaller denier fibers offers the advantage of a thinner fabric than the fabric included by a conventional monofilament, without sacrificing resistance of the tissue.

Claims (13)

1. A fabric for use in the sections of forming, pressing or drying of a machine for the manufacture of paper, the fabric having at least one layer comprised of a thread of composite material comprised of: a first thread of a filament material of high module within a second thread, in which the second thread is a material of two component filament, having the filament material of two components a cover component and a component of core, in which the two component filament material Coats the first high modulus filament material, and encloses to the first high modulus filament material along the Length of composite thread. 2. The fabric according to claim 1, wherein the threads that comprise the fabric are braided. 3. The fabric according to claim 1, wherein the threads that comprise the fabric are gathered together. 4. The fabric according to claim 1, wherein composite threads extend in the directions of The warp and the weft. 5. The fabric according to claim 1, wherein the composite threads extend in the direction of the warp. 6. The fabric according to claim 1, wherein the composite threads extend in the direction of the plot. 7. The fabric of claim 1, wherein the first high module material is selected from the group consisting in high modulus polyamides, aramid, poly (naphthalate ethylene), fiberglass, thermotropic materials, copolyesters aromatic, poly (p-phenylenebenzobistiazole), polyesters, and high modulus polyethylene fibers, and their mixtures 8. The fabric of claim 1, wherein the
cover-core combinations of the two fibers
components are selected from copolyester / poly (ethylene terephthalate), polyamide / poly (ethylene terephthalate), polyamide / polyamide, polyether combinations
tylene / poly (ethylene terephthalate), polypropylene / poly (ethylene terephthalate), polyethylene / polyamide, poly-
propylene / polyamide, thermoplastic polyurethane / poly-
liamide and thermoplastic polyurethane / poly (ethylene terephthalate). 9. The fabric of claim 1, wherein the high modulus filament material is further comprised of a plurality of high modulus filaments. 10. The fabric of claim 1, wherein the two component filament material is further included by a plurality of two component threads, being comprised in addition each thread of two components by filaments of two components that have a cover and core arrangement. 11. The fabric of claim 1, wherein the tissue is heated to a temperature greater than the point of fusion of the cover component, but less than the point of melting of the core component, and cools to a temperature less than the melting point of the roof component. 12. The fabric of claim 1, wherein the composite yarn is melted by heat before the tissue formation 13. The fabric of claim 1, wherein The fabric is a single layer fabric.