RU2205911C2 - Flexible structure comprising starch filaments - Google Patents

Abstract

FIELD: manufacture of flexible structures. SUBSTANCE: flexible structure is manufactured with the use of starch filaments and has at least first and second portions, each of said portions possessing at least one common intensive property selected from group of properties such as density, basic weight, height, non-transparency, creping frequency or any combination thereof. Common intensive property of first portion differs from that of second portion in value. EFFECT: improved strength, absorbing capacity and softness of flexible structure composed of plurality of starch filaments. 33 cl, 11 dwg, 1 tbl

Description

 The invention relates to flexible structures containing starch filaments, and more particularly, flexible structures having different regions.

 Cellulose fiber nonwovens, such as paper, are well known in the art. Currently, low density nonwoven fibrous materials are commonly used for the manufacture of paper towels, toilet paper, handkerchiefs, wipes, wet wipes, etc. The great demand for such paper products caused the need for improved varieties of these products and methods for their manufacture. To meet these needs, manufacturers in the paper industry must balance the cost of equipment and resources with the total cost of delivering products to the consumer.

 In conventional paper manufacturing processes, wood pulp fibers are pulled, ground, or refined to achieve a certain degree of hydration of the fibers to form an aqueous fiber slurry. Paper material manufacturing processes for use in the manufacture of tissue paper, tissue paper, and hygiene products typically include preparing an aqueous suspension and then removing water from the suspension while rearranging the fibers therein to form a paper web. After dewatering, the web is processed to produce a dry roll or sheets and, ultimately, converted into a consumer packaging container. To carry out the dehydration process and processing operations, it is necessary to use equipment of various types, which requires significant investment.

 Another aspect of the conventional papermaking process is the incorporation of various additives into the pulp in order to achieve certain final properties. For example, additives are often used in the paper industry, such as resins, loosening surfactants, plasticizers, pigments, latexes, polymer microspheres, flame retardants, dyes, perfumes, etc. The effective retention of these additives on the wet side of the papermaking process is a challenge for the manufacturer, since the portion that is retained not only leads to economic losses, but also creates significant pollution problems if it becomes part of industrial waste water. In addition, additives can be added to the paper web after the dehydration step by means of coating or impregnation operations generally known in the art. These operations typically require the consumption of additional thermal energy for re-drying the paper after coating. In addition, in some cases, solvent-based coating compositions are necessary, which increases capital costs and requires the extraction of volatile substances to meet the requirements of regulatory authorities.

 For the manufacture of paper, other natural fibers other than cellulose and various synthetic fibers were used, however, all these substitutes were unsuitable as industrially acceptable substitutes for cellulose due to their high cost, poor binding ability, chemical incompatibility and difficulties in handling them. production equipment. As a substitute for cellulose in various fields of papermaking, starch yarns have been proposed, but attempts to use such starch yarns in industry have been unsuccessful. As a result, paper materials are still made exclusively from wood-based cellulosic ingredients.

Closest to the claimed invention is a flexible structure containing starch filaments, and a method for its production, disclosed in EP 1035239 A2, IPC D 01 F 9/00, 09/13/2000 of the same applicant. The known flexible structure contains many starch filaments and has a density of from 0.02 g / cm ³ to 0.20 g / cm ³ , the bulk is from 10 g / m ² to 450 g / m ² , while starch fibers have a size of from 0 , 01 decitex to 135 decitex, glass transition temperature from -30 ^o C to 150 ^o C. This flexible structure is obtained by a method involving the manufacture of many starch filaments, depositing them on the receiving side of the forming element.

 From patent GH 609539, IPC7 A 41 B 13/02, 03/15/1979, a flexible structure is known - absorbent litter - from cellulose pulp having sections with a high density and sections with a low density.

 The objective of the invention is to remedy the above disadvantages.

 Thus, the present invention provides a flexible structure containing long starch fibers, and a method for their manufacture. In particular, the present invention provides a flexible structure comprising a plurality of starch filaments, the structure comprising one or more regions having distinct intense properties with respect to improved strength, absorbency and softness.

 In addition, the present invention provides methods for making starch filaments. In particular, the present invention provides an electroforming process for manufacturing a plurality of starch filaments.

 The flexible structure contains many starch filaments. At least some of the many starch filaments have a size of from about 0.001 decitex to about 135 decitex, and more particularly from 0.01 decitex to 5 decitex. The ratio of the length of the main axis of at least some starch filaments to the equivalent cross-sectional diameter perpendicular to the main axis of starch filaments is greater than 100/1, more specifically more than 500/1, more specifically more than 1000/1 , and more specifically, more than 5000/1.

 The structure contains at least a first region and a second region, wherein each of the first and second regions has at least one common intense property selected from the group consisting of density, bulk, height, opacity, frequency, creping and any combination thereof. At least one common intensive property of the first region is different in magnitude from at least one common intensive property of the second region.

 In one embodiment of the invention, one of the first and second regions is a substantially continuous grid, and the other of the first and second regions is a plurality of distinct regions dispersed throughout a substantially continuous grid. In another embodiment of the invention, at least one of the first and second regions is a semicontinuous mesh.

 The flexible structure may further comprise at least a third region having at least one intense property that is common with the intensive property of the first region and the intensive property of the second region, but differs in magnitude. In one embodiment, at least one of the first, second, and third regions may be a substantially continuous grid. In another embodiment, the at least one of the first, second, and third regions may comprise separate or discontinuous portions. In yet another embodiment of the invention, at least one of the first, second, and third regions may comprise substantially semi-continuous portions. In yet another embodiment of the invention, at least one of the first, second, and third regions may comprise a plurality of distinct regions dispersed throughout a substantially continuous grid.

 In an embodiment of the invention in which the flexible structure comprises at least one substantially continuous mesh region and a plurality of discrete sections dispersed throughout the substantially continuous mesh region, the substantially continuous mesh region may have a relatively high density compared to a relatively low density of the plurality separate sites. When the structure is located on the horizontal reference plane, the first region defines the first height, and the second region extends outward from the first region, determining the second height more (relative to the horizontal reference plane) than the first height.

 In an embodiment of the invention containing at least three regions, the first region may determine a first height, the second region may determine a second height, and the third region may be a third height when the structure is located on a horizontal reference plane. At least one of the first, second, and third heights may be different from at least one of the other heights, for example, the second height may be intermediate between the first height and the third height.

 In one embodiment of the invention, the second region comprises a plurality of starch cushions, at least some of the cushions may comprise a protruding portion extending from a first height to a second elevation and a cantilever portion extending laterally from the protruding portion at a second height. The density of the starch cantilever part may be equal to, at least one of the density of the first region and the density of the second region, or be intermediate between the density of the first region and the density of the protruding part. The cantilever portions are usually elevated above the first plane to form substantially free spaces between the first region and the cantilever portions.

A flexible structure can be made by forming a plurality of starch filaments by melt spinning, dry spinning, wet spinning, electrospinning, or any combination thereof; the use of a forming element that is permeable to the fluid and containing a reinforcing element connected to the embossed polymer base having at least one through hole, a thread receiving side, made with a relief for receiving a plurality of starch filaments, and a back side opposite to the thread receiving side wherein the reinforcing element is located between the thread receiving side and at least a portion of the back side of the base, and the thread receiving side contains a substantially continuous relief, essentially lunepreryvny relief intermittent relief or any combination thereof,
depositing a plurality of starch filaments on the thread receiving side of the forming element, while the plurality of starch filaments are at least partially snug against the relief of the thread receiving side of the warp,
applying a fluid pressure differential to the plurality of starch filaments to thereby form the first regions of the plurality of filaments supported by the corrugated base and the second regions of the plurality of starch filaments deflected into at least one opening thereof and supported by a reinforcing element, and
separating the plurality of starch filaments from the forming element, thereby forming a flexible structure comprising a first region and a second region.

 A flexible structure containing starch filaments can also be made by a method that comprises the steps of manufacturing a plurality of starch filaments, using a forming element having a filament receiving side and a reverse side opposite thereto, wherein the filming side has a three-dimensional relief, and depositing a plurality of starch filaments on the take-up side of the forming element, and cause many starch filaments to at least partially fit snugly against the three-dimensional relief.

 The step of using a forming element may include using a forming element in which the three-dimensional relief of the take-up side comprises a substantially continuous relief, a substantially semi-continuous relief, a relief containing many individual protrusions, or any combination thereof. The step of using a forming member also includes using a forming member that comprises a polymer base coupled to the reinforcing member, or using a forming member that is breathable.

 The base may contain many through holes, which can be continuous, separate or semi-continuous, similar to or opposite to the relief of the base.

 In one embodiment of the invention, the forming element is formed by a reinforcing element located at a first height, and a polymer base connected to the reinforcing element when the surface is located to the surface and extends outward from the reinforcing element to the second height. The forming element may consist of many interwoven threads, cloth or any combination thereof.

 When a plurality of starch filaments are deposited on the take-up side of the forming element, due to their flexibility and / or as a result of the application of a differential pressure of the fluid, they tend to at least partially fit snugly against the three-dimensional relief of the forming element, and the first regions of the plurality of starch filaments are formed, supported by a corrugated base, and second regions of a plurality of starch filaments deflected into its opening or openings and supported by a reinforcing element.

 In addition, the step of using a forming element includes the use of a forming element having suspended parts.

 In one embodiment of the invention, the forming member comprises hanging parts. The polymer base of such a forming element comprises a plurality of supports extending outward from the reinforcing element, and a plurality of cantilever parts extending laterally from the supports at a second height to form free spaces between the cantilever parts and the reinforcing element, wherein the plurality of supports and the plurality of cantilever parts in combination form a three-dimensional take-up side of the forming element. Such a forming element can be formed by at least two layers joined together to position the surface to the surface, so that parts of the mesh of one of the layers correspond to holes in the other layer. A forming element containing suspension parts can be formed by differential curing of the photosensitive polymer layer through a mask having a pattern with areas of different opacity.

 The step of depositing a plurality of starch filaments onto the take-up side of the forming element and causing at least a partial snug fit of the plurality of starch filaments to its three-dimensional relief involves applying a pressure differential of the fluid to the plurality of starch filaments.

 The method may further comprise the step of compacting selected portions of the plurality of starch filaments, which includes applying mechanical pressure to the plurality of starch filaments.

 In this case, the step of depositing a plurality of starch filaments on the thread receiving side of the forming element includes deposition of starch filaments at an acute angle thereto, the acute angle being from about 5 degrees to about 85 degrees.

 The step of manufacturing a plurality of starch filaments includes melt spinning, dry spinning, wet spinning, or any combination thereof.

 The ratio of the length of the main axis of at least some starch filaments to the equivalent cross-sectional diameter perpendicular to the main axis of starch filaments is at least 100/1.

 In this case, starch filaments have a size from about 0.001 decitex to about 135 decitex.

 The method may further comprise the step of pre-cutting a plurality of starch filaments, which includes creping, micro-shortening, or a combination thereof.

 An electroforming method for making starch filaments comprises the steps of forming a starch composition having a tensile viscosity of from about 50 Pa • s to about 20,000 Pa • s, and electroforming from a starch composition of starch filaments ranging in size from about 0.001 dtex to about 135 dtex. The step of electroforming from a starch composition is typically carried out by electroforming through a die.

 The starch in the starch composition has a weight average molecular weight of from about 1,000 to about 2,000,000, and the starch composition has a capillary number of at least 0.05 and more specifically at least 1.00. In one embodiment, the starch composition comprises from about 20% to about 90% by weight of amylopectin. The starch in the starch composition may have a weight average molecular weight of from about 1,000 to about 2,000,000. The starch composition may contain a high molecular weight polymer having a weight average molecular weight of at least 500,000.

The starch composition may contain from about 10 wt.% To about 80 weight. % starch and from about 20 wt.% to about 90 wt.% additives. Such a starch composition may have a tensile viscosity of from about 100 Pa • s to about 15000 Pa • s at a temperature of from about 20 ^{° C.} to about 180 ^° C.

The starch composition may contain from about 20 wt.% To about 70 weight. % starch and from about 30 wt.% up to about 80 wt.% additives. Such a starch composition may have a tensile viscosity of from about 200 Pa • s to about 10,000 Pa • s at a temperature of from about 20 ^{° C.} to about 100 ^° C.

 A starch composition having a tensile viscosity of from about 200 Pa • s to about 10,000 Pa • s may have a capillary number of from about 3 to about 50. More specifically, a starch composition having a tensile viscosity of from about 300 Pa • s to about 5,000 Pa. • s, may have a capillary number from about 5 to about 30.

 In one embodiment, the starch composition comprises from about 0.0005% to about 5% by weight of a high molecular weight polymer that is substantially compatible with starch and has a weight average molecular weight of at least 500,000.

 The starch composition may contain additives selected from the group consisting of plasticizers and diluents. Such a starch composition, in addition, may contain from about 5 wt.% To about 95 wt.% Protein, while the protein may be corn protein, soy protein, wheat protein, or any combination thereof.

 A method of manufacturing starch filaments, in addition, may include the stage of stretching starch filaments with air jets.

 In one embodiment of the invention, a method for manufacturing a flexible structure comprising starch filaments comprises the steps of: forming a starch composition having a tensile viscosity of from about 100 Pa • s to about 10,000 Pa • s; using a forming element having a three-dimensional thread receiving side and a rear side opposite to it, while the thread receiving side has a substantially continuous relief, a substantially semi-continuous relief, an intermittent relief, or any combination thereof; electroforming a starch composition, thereby producing a plurality of starch filaments; and depositing a plurality of starch filaments on the take-up side of the forming element, wherein the starch threads adapt to the three-dimensional topography of the take-up side.

 In an industrial process, the forming element continuously moves in the longitudinal direction.

Brief Description of the Drawings
Figure 1 is a schematic top view of one embodiment of a flexible structure according to the present invention;
figa is a schematic view in section along the line 1A-1A in figure 1;
FIG. 2 is a schematic top view of another embodiment of a flexible structure according to the present invention;
FIG. 3 is a schematic sectional view of another embodiment of a flexible structure according to the present invention;
FIG. 4 is a schematic top view of one embodiment of a forming member that can be used to form a flexible structure according to the present invention;
figa is a schematic view in section along the line 4A-4A in figure 4;
FIG. 5 is a schematic top view of another embodiment of a forming element that can be used to form a flexible structure according to the present invention;
Fig. 5a is a schematic sectional view taken along line 5A-5A of Fig. 5;
FIG. 6 is a schematic sectional view of yet another embodiment of a forming element that can be used to form a flexible structure according to the present invention;
FIG. 7 is a schematic partial side and cross-sectional view of an embodiment of an electrospinning method and apparatus for manufacturing a flexible structure containing starch filaments;
Fig. 7a is a schematic sectional view taken along line 7A-7A in Fig. 7;
FIG. 8 is a schematic side view of another embodiment of a method according to the present invention;
FIG. 9 is a schematic side view of another embodiment of a method according to the present invention;
FIG. 9A is a schematic partial side view of another embodiment of a method according to the present invention;
10 is a schematic view of an embodiment of a segment of a starchy filament having different cross-sectional areas perpendicular to the main (longitudinal) axis of the filament;
figa is a schematic view of several exemplary, non-exclusive variants of the cross-sectional area of the starch filament;
FIG. 11 is a schematic view of a section of a starch filament having a plurality of notches in at least a portion of the length of the filament.

 The following terms have the following meanings when used in the description.

 A “flexible structure containing starch filaments” or simply a “flexible structure” is a structure containing a plurality of starch filaments that are mechanically intertwined to form a sheet-like material having defined microscopic geometric, physical or aesthetic properties.

 A “starch yarn” is a thin and very flexible item containing starch and having a main axis that is very long compared to two mutually perpendicular yarn axes that are perpendicular to the main axis. The ratio of the length of the main axis to the equivalent diameter of the cross section of the thread perpendicular to the main axis is more than 100/1, more specifically, more than 500/1, more specifically more than 1000/1, and more specifically more than 5000/1. Starch filaments may contain another substance, such as, for example, water, plasticizers and other optional additives.

"Equivalent diameter" is used here to determine the cross-sectional area and surface area of an elementary starch filament regardless of the shape of the cross-sectional area. Equivalent diameter is a parameter that satisfies the equation S = 1 / 4πD ² , where S is the cross-sectional area of the starch filament (regardless of its geometric shape), π = 3.14159 and D is the equivalent diameter. For example, a rectangular cross-section formed by two mutually opposite sides of "A" and two mutually opposite sides of "B" can be expressed as: S = AxB. At the same time, this cross-sectional area can be expressed as the area of a circle having an equivalent diameter D. Further, the equivalent diameter D can be calculated by the formula S = 1 / 4πD ² , where S is the known area of the rectangle. (Of course, the equivalent diameter of a circle is the actual diameter of a circle). Equivalent radius is 1/2 equivalent diameter.

 "Pseudo-thermoplastic" in connection with "materials" or "compositions", as is meant, means materials and compositions that, under the influence of elevated temperatures, dissolution in an appropriate solvent or otherwise, can be softened to such an extent that they can be given in a fluid state in which they can be molded as desired, and more specifically processed to form starch filaments suitable for forming a flexible structure. Pseudo-thermoplastic materials can be molded under the combined action of heat and pressure. Pseudo-thermoplastic materials differ from thermoplastic materials in that the softening or liquefaction of pseudo-thermoplastics is caused by the present softeners and solvents, without which it would not be possible to bring them by any temperature or pressure into the soft or fluid state necessary for molding, since pseudo-thermoplastics as such are not “melted”. The effect of moisture content on the glass transition temperature and melting point of starch can be measured by differential scanning calorimetry described by Zeleznak and Hoseny in "Cereal Chemistry", Vol. 64 2, pp. 121-124, 1987. A pseudo-thermoplastic melt is a pseudo-thermoplastic material in a fluid state.

 "Microgeometry" and its changes refer to the relatively small (i.e., "microscopic") details of a flexible structure, such as, for example, the surface texture, regardless of the general configuration of the structure, as opposed to its general (i.e., "macroscopic") geometry. Terms containing “macroscopic” or “macroscopically” refer to the general geometry of a structure or part thereof when considered in a two-dimensional configuration, for example, in the X-Y plane. For example, at the macroscopic level, a flexible structure, when it is located on a flat surface, is a relatively thin and flat sheet. However, at the microscopic level, the structure may contain many first regions that form a first plane having a first height (vertical section), and many bulges or “pillows” scattered throughout the mesh region and extending outward from it to a second height.

 "Intensive properties" are properties that do not have a value that depends on the totality of values within the plane of the flexible structure. A common intensive property is an intensive property that more than one area possesses. Such intense properties of the flexible structure of the present invention include, but are not limited to, density, bulk, height, opacity, and creping frequency (if the structure is subject to prior reduction). For example, if density is a common intense property of two different regions, then the density in one region may differ from the density in another. Regions (such as, for example, the first region and the second region) are recognizable zones distinguished from one another by individual intense properties.

 “Base weight” is the weight (measured in gram-force) of a unit area of a starch flexible structure, and the unit of area is measured in the plane of the structure of starch filaments. The size and shape of the unit of area by which the base weight is measured depends on the relative and absolute sizes and shapes of areas having different base weights.

"Density" is the ratio of the base weight to the thickness (measured perpendicular to the plane of the flexible structure) of the area. Apparent density is the bulk of the sample divided by the thickness in thousandths of an inch using the appropriate conversion factors from one unit to another. The apparent density used here is expressed in units of grams / cubic centimeter (g / cm ³ ).

 “Thickness in thousandths of an inch” is the macroscopic thickness measured as described below. This thickness should be distinguished from the height of the various regions, which is a microscopic characteristic of the regions.

"Glass transition temperature", T _g is the temperature at which the material changes from a viscous or elastic state to a solid or relatively brittle state.

 A “longitudinal direction” (or PN) is a direction parallel to the technological route of a flexible structure being manufactured through production equipment. A “transverse direction" is a direction perpendicular to the longitudinal direction and parallel to the general plane of the flexible structure being produced.

 “X”, “Y” and “Z” denote the usual Cartesian coordinate system in which the mutually perpendicular coordinates “X” and “Y” define the reference plane, and “Z” defines the perpendicular to the X-Y plane. "Z-direction" means any direction perpendicular to the X-Y plane. Similarly, the term "Z-dimension" refers to a dimension, distance, or parameter measured parallel to the Z-direction. When an element, such as a forming element, bends or otherwise ceases to be flat, the X-Y plane follows the configuration of the element.

 “Essentially continuous” area (section / grid / base) is the area within which any two points can be connected by a continuous line that runs completely within this area throughout its entire length. Namely, a substantially continuous region has substantial “continuity” in all directions parallel to the first plane, and ends only at the edges of this region. The term “substantially” in combination with the term “continuous” as meant, indicates that although absolute continuity is preferred, slight deviations from absolute continuity may be allowed, as long as these deviations do not significantly affect the intended and intended characteristics of the flexible structure (or forming element).

 An “essentially semicontinuous” region (section / grid / base) is an area that has “continuity” in all but at least one direction parallel to the first plane, and in which it is impossible to connect any two points with a continuous line passing completely within this area throughout its entirety. A semicontinuous base can have continuity in only one direction parallel to the first plane. By analogy with the continuous region described above, although absolute continuity is preferred in all but at least one direction, slight deviations from such continuity can be allowed until these deviations have a noticeable effect on the characteristics of the structure (forming element).

 “Discontinuous” areas are areas that are separate or separated from one another, which are discontinuous in all directions parallel to the first plane.

 "Absorbent ability" is the ability of a material to perceive liquids by various means, including capillarity, osmosis, solvent or chemical action, and to retain such liquids. Absorbency can be measured in accordance with the test described below.

 "Flexibility" is the ability of a material or structure to not deform under a given load without breaking, regardless of the ability or inability of the material or structure to return to its shape before deformation.

 A “forming element” is a structural element that can be used as a support for starch filaments, which can be deposited on it during the manufacturing process of the flexible structure according to the present invention, and as a forming device for the formation (or “molding”) of the desired microscopic geometry of the flexible structure according to the present invention. The forming element can be any element that has the ability to give a three-dimensional relief to the structure made on it, and is made in the form (but not limited to) of a plate, tape, woven fabric and strip.

 "Reinforcing element" is a desirable but optional element in some embodiments of the forming element, serving mainly to ensure or promote the integrity, stability and durability of the forming element containing, for example, a polymeric material. The reinforcing element may be permeable, impermeable or partially permeable to the fluid and may consist of interwoven yarns, cloth, plastic, other suitable synthetic material, or any combination thereof.

 A “pressing surface” is a surface that can be pressed against the thread receiving side of a forming element having a plurality of starch filaments in it to bend, at least partially, the starch filaments into a forming element having a three-dimensional relief with depressions and protrusions.

 "Decitex" or "dtex" is a unit of measure for starch filament, expressed in grams per 10,000 meters, g / 10,000 m.

 “Melt forming” is a method in which a thermoplastic or pseudoplastic material is converted into a fibrous material by a pulling force. Melt forming may include mechanical stretching, melt spinning with gas flow, spinning (spinning) bonding and electrospinning.

 "Mechanical drawing" is a method of applying force to an elementary thread by bringing it into contact with a moving surface, for example, a roller for applying force to the melt and thereby making the filament.

 “Gas-jet melt spinning” is a method of manufacturing fibrous non-woven materials or articles directly from polymers or resins using a high-speed air stream or other suitable force to draw threads. With this method, the pulling force is applied in the form of a high-speed air stream when the material leaves the die.

 "Spinning" is a method in which an elementary fiber is allowed to fall a predetermined distance under the influence of flow forces and gravity and then subjected to the action of a force exerted by a high-speed air stream or other appropriate source.

 "Electroforming" is a method in which an electric potential is used as a force for drawing fibers.

 "Dry spinning", also commonly known as "spin-molding", includes drying from a solvent to stabilize the spinning of the fiber. The material is dissolved in an appropriate solvent and stretched by mechanical stretching, drawing by high-speed gas flow, spun and / or electrospinning. As the solvent evaporates, the fiber becomes stable.

 "Wet forming" includes dissolving a material in an appropriate solvent and spinning small fibers by mechanical drawing, drawing by high speed gas flow, spun and / or electrospinning. After forming the fiber, it is introduced into a coagulation device, usually a bath filled with an appropriate solution that cures the desired material, whereby stable fibers are produced.

 A high molecular weight polymer that is “substantially compatible with starch” means that the high molecular weight polymer is capable of forming a substantially uniform starch composition (i.e., a composition that looks transparent or translucent to the naked eye) when the composition is heated to a temperature above its softening temperature and / or melting.

 "Melting point" means the temperature or temperature range at which or above which the starch composition melts or softens sufficiently to be capable of being processed into starch filaments according to the present invention. It should be noted that some starch compositions are pseudo-thermoplastic compositions and, as such, may not manifest themselves as truly “melting” compositions.

 "Processing temperature" means the temperature of the starch composition at which the starch filaments of the present invention can be formed, for example, by drawing.

Flexible structures
Referring to FIG. 1-3, in which a flexible structure 100 containing pseudo-thermoplastic starch filaments has at least a first region 110 and a second region 120. Each of the first and second regions has at least one common intense property, such as a main weight or density. The overall intensive property of the first region 110 is different in magnitude from the general intensive property of the second region 120. For example, the density of the first region 110 may be greater than the density of the second region 120.

 The first and second regions 110 and 120 of the flexible structure 100 according to the present invention may also differ in their respective microgeometry. For example, in FIG. 1, the first region 110 is a substantially continuous grid defining a first plane at a first height when the structure 100 is located on a flat surface, and the second region 120 may be a plurality of distinct regions dispersed throughout a substantially continuous grid. In some embodiments of the invention, these individual sections may be separate protrusions or "cushions" extending outward from the mesh area to a second height that is larger than the first height relative to the first plane. It will be appreciated that the pillows can also form a substantially continuous pattern and a substantially semi-continuous pattern.

 In one embodiment, the substantially continuous mesh region may have a relatively high density and the pillows a relatively low density. In another embodiment, the substantially continuous net area may have a relatively small base weight, and the pillows a relatively large base weight. In yet another embodiment, the substantially continuous mesh region may have a relatively low density, and the pillows a relatively high density. An embodiment of the invention is possible in which a substantially continuous net region may have a relatively large base weight and the pillows a relatively small base weight.

 In other embodiments, the second region 120 may be a semicontinuous mesh. In FIG. 2, the second region 120 comprises separate sections 122, similar to those shown in FIG. 1, and semicontinuous sections 121, as seen, extending in at least one direction in the X-Y plane (i.e. in the plane formed by the first region 110 of the structure 100 located on a flat surface).

 In the embodiment of the invention shown in FIG. 2, the flexible structure 100 comprises a third region 130 having at least one intense property that is common with, but differs from, the intensive property of the first region 110 and the intensive property of the second region 120 size. For example, the first region 110 may have a common intensive property having a first magnitude, the second region 120 may have a common intensive property having a second magnitude, and the third region 130 may have a common intensive property having a third magnitude, wherein the first magnitude may differ from the second magnitude, and the third value may differ from the second value and the first value.

 When the structure 100, containing at least the three different regions described above 110, 120, 130, is located on a horizontal reference plane (for example, the X-Y plane), the first region 110 defines a plane having a first height, and the second region 120 extends from her, defining a second height. An embodiment of the invention is possible in which the third region 130 defines a third height, wherein at least one of the first, second and third heights is different from at least one of the other heights. For example, the third height may be intermediate between the first and second heights.

 The following table, without limitation, shows some possible embodiments of a structure 100 comprising at least three regions having different (i.e., high, medium, or distinctive) intense properties. All of these options are within the scope of the present invention.

 In FIG. 3 shows yet another embodiment of the flexible structure 100 according to the present invention, in which the second region 120 comprises a plurality of starch cushions, at least some of the cushions comprising a starchy convex portion 128 and a starchy cantilever portion 129 extending from the starchy convex portion 128 The starch cantilever portion 129 is raised above the X-Y plane and extends at an angle from the convex portion 128, forming substantially free spaces or “pockets” 115 between the first starchy convex region 110 portions 128 extending from it, and starchy console portions 129.

 Largely due to the existence of these essentially free pockets 115, capable of absorbing and holding a significant amount of fluid, the flexible structure 100 shown schematically in FIG. 3 is believed to exhibit a very high absorbent capacity based on a given base weight. Pockets 115 are distinguished by the fact that they do not have any starch filaments or they are present in very small quantities.

One skilled in the art will appreciate that, due to the manufacturing process of the flexible structure 100 described below, and due to the very flexible nature of the starch filaments and the flexible structure 100 as a whole, some pockets of starch filaments may be allowed in pockets 115 until these starch filaments affect the intended relief of structure 100 and its proposed properties. In this regard, the term “substantially” free pockets 115 is believed to express that, due to the very flexible nature of structure 100 and the elementary starch filaments constituting structure 100, some insignificant amount of starch filaments or parts thereof may end up in pockets 115 The density of pockets 115 is not more than 0.005 grams per cubic centimeter (g / cm ³ ), more specifically, not more than 0.004 g / cm ³ , and even more specifically, not more than 0.003 g / cm ³ .

 According to another aspect, the flexible structure 100 containing the cantilever parts 129 is characterized by an increased total surface area compared to the total surface area of a comparable structure without cantilever parts 129. As one skilled in the art will recognize, the greater the number of individual cantilever parts 129 and their corresponding microscopic surface areas, the greater the total microscopic specific surface area (i.e., the total microscopic surface area per unit of total macroscopic area di structure disposed on a flat surface). As is also clear to a person skilled in the art, the larger the area of the absorbent surface of the structure, the greater its absorbing capacity, with all other equal parameters.

 In embodiments of the structure 100 comprising the cantilever portions 129, the cantilever portions 129 may be third regions of the structure 100. For example, it is possible that the density of the starchy cantilever portions 129 is intermediate between the density of the first region 110 and the density of the second region 120 containing the protruding portion (parts). In another embodiment of the structure, the density of the protruding part 128 may be intermediate between the relatively high density of the first region 110 and the relatively low density of the cantilever part 129. Similarly, the main weight of the cantilever part 129 may be equal to or greater than the main weight of one of the first region 110 and the protruding parts 128, or both of them, or be intermediate between their main weights.

A method of manufacturing a flexible structure
In FIG. 8 and 9 schematically show two embodiments of a method for manufacturing a flexible structure 100 comprising starch filaments.

 First, they form many starch filaments. The production of starch filaments for flexible structure 100 according to the present invention can be carried out in various ways known from the prior art. For example, starch filaments can be made from pseudo-thermoplastic molten starch compositions using various melt spinning methods. The sizes of starch filaments can vary from about 0.001 decitex to about 135 decitex, more specifically from about 0.005 decitex to about 50 decitex, and even more specifically from about 0.01 decitex to about 5.0 decitex.

Some sources, including US Pat. No. 4,139,699, issued to Hermandes et al. On February 13, 1979; U.S. Patent 4,853,168, issued to Eden et al. on August 1, 1989; U.S. Patent 4,234,480 to Germandez et al., January 6, 1981; US Pat. Nos. 5,516,815 and 5,316,578 to Buler et al. relate to starch compositions for making starch.
filaments using a melt spinning method. The molten starch composition can be extruded through a die to produce filaments having diameters slightly increased compared to the diameter of the holes of the die (i.e., due to swelling of the extruded stream). Then the threads are mechanically or thermomechanically pulled by an exhaust device to reduce their diameter.

 Several devices are known in the art for the manufacture of nonwoven thermoplastic fabric structures from extruded polymers, which may be suitable for the manufacture of long starch filaments. For example, an extruded starch composition can be pressed through a die (not shown) forming a vertically oriented curtain of downwardly moving starch filaments. Starch filaments can be air-cooled using a suction air duct for drawing or thinning. US Pat. No. 5,292,239, issued March 8, 1994 to Zeldin et al., Describes a device that reduces significant turbulence in the air stream, providing uniform and constant application of the pulling force to starch filaments. The description of this patent is incorporated herein by reference with the limited purpose of familiarizing oneself with methods and equipment for reducing turbulence in the air stream during the formation of starch filaments.

 For the implementation of the present invention, starch filaments can be made from a mixture containing starch, water, plasticizers and other optional additives. For example, a suitable starch mixture can be converted into a pseudo-thermoplastic melt in an extruder and passed through a die to a drawing device forming a vertically oriented curtain of downwardly moving starch filaments. The die may be a device that is known in the art. The die may contain many channels with holes having cross-sectional areas suitable for the production of starch filaments. The die can be made taking into account the fluidity of the starch composition, so that, if desired, the same flow rate is provided in the channels. On the other hand, there may be different flow rates in different channels.

 A pulling device (not shown) may be located downstream of the extruder and may comprise an open upper end, an opposite lower end and a distribution conduit for supplying compressed air to the downstream nozzles. When compressed air flows through the internal nozzles, air is drawn into the open upper end of the extraction device, forming a fast-moving air stream flowing downward. The air flow creates a pulling force acting on the starch filaments and causing them to thin or stretch before leaving the open lower end of the drawer.

 As it has now been discovered, starch filaments suitable for flexible structure 100 can be made by an electroforming method in which an electric field is applied to a starch solution to form a charged starch stream. An electroforming method is known in the art. A 1994 dissertation by Doshi, Jayesh, Natwarlal, Ph.D. entitled "The Electro-Spinning Process and Applications of Electro-Spun Fibers" describes the electroforming process and investigates the forces involved in this process. This dissertation also examines some areas of industrial application of threads made by electroforming. This dissertation is hereby incorporated by reference in order to describe the main features of electroforming processes.

 The method of electroforming and the equipment used for them are described in US patents 1975504 (October 2, 1934), 2123992 (July 19, 1938), 2116942 (May 10, 1938), 2109333 (February 22, 1938). 2160962 (June 6, 1939), 2187306 (January 16, 1940), and 2158416 (May 16, 1939), which are all issued in the name of Formhals. Other sources describing electroforming methods include US Patents 3,280,229 (October 18, 1966), issued in the name of Simons; 4044404 (August 30, 1977), issued in the name of Martin et al .; 4069026 (January 17, 1978), issued in the name of Simm et al .; 4,143,196 (March 6, 1979), issued in the name of Simm; 4,223,101 (September 16, 1980), issued in the name of Fain and others; 4,230,650 (October 28, 1980), issued in the name of Guinard; 4,232,525 (November 11, 1980), issued in the name of Angio et al .; 4,287,139 (September 1, 1981), issued in the name of Guinard; 4323525 (April 6, 1982), issued in the name of Bornat; 4,552,707 (November 12, 1985), issued in the name of Howe; 4,689,186 (August 25, 1987), issued in the name of Bornat; 4,798,607 (January 17, 1989), issued to Middleton et al .; 4904272 (February 27, 1990), issued in the name of Middleton et al .; 4968238 (November 6, 1990), issued in the name of Satterfield and others; 5,024,789 (January 18, 1991), issued in the name of Barry; 6106913 (August 22, 2000), issued in the name of Skardino et al., And 6110590 (August 29, 2000), issued in the name of Zarkob and others. The contents of the above patents are hereby incorporated by reference with the limited purpose of describing the main features of electrospinning methods and equipment for their implementation.

 Although the above sources offer a variety of electroforming methods and equipment for their implementation, they do not suggest that the starch composition can be successfully processed and extruded into thin, essentially continuous starch filaments suitable for forming the flexible structure 100 according to the present invention. Naturally occurring starch cannot be processed by electrospinning, since natural starch usually has a granular structure. As it has now been discovered, a modified, “degraded” starch composition can be successfully processed using the electroforming method.

 An applicant patent application entitled “Melt-processable starch composition” (Larry Neil Mackey et al. Attorney dossier 7967R) and filed on the filing date of this application describes a starch composition that is suitable for the production of starch filaments used in flexible structure 100 according to the present invention. This starch composition contains starch having a weight average molecular weight in the range of from 1000 to about 2,000,000, and may contain a high molecular weight polymer that is substantially compatible with starch and has a weight average molecular weight of at least 500,000. In one embodiment, this starch composition may have from about 20 wt.% to about 99 wt.% amylopectin. A description of this application is incorporated herein by reference.

 According to the present invention, the starch polymer can be mixed with water, plasticizers and other additives, and the resulting melt can be processed (for example, extruded) and molded to produce starch filaments suitable for the flexible structure of the present invention. Starch filaments may contain starch from trace amounts to one hundred percent or be a mixture of starch and other suitable substances, such as cellulose, synthetic substances, proteins and any combination thereof.

 Among the starch polymers can be any naturally occurring starch, physically modified starch or chemically modified starch. Suitable naturally occurring starches include, but are not limited to, corn starch, potato starch, sweet potato starch, wheat starch, sago palm starch, cassava starch, rice starch, soy starch, starch from marmara roots, starch, starch lotus, waxy corn starch, high amylose corn starch and commercially available amylose powder. Naturally occurring starches, especially corn starch, potato starch and wheat starch, are preferred starch polymers because of their availability.

 Physically modified starch is obtained by changing its dimensional structure, physically modified starch may contain α-starch, fractionated starch, moisture, heat-treated starch and mechanically processed starch.

 Chemically modified starch can be formed by the reaction of its OH groups with alkylene oxides and other substances forming an ether, ester, urethane, carbamate or isocyanate. Among the varieties of chemically modified starches are hydroxyalkyl, acetyl and carbamate starches or mixtures thereof. The degree of substitution of chemically modified starch is from 0.05 to 3.0, and more specifically, from 0.05 to 0.2.

 The natural water content may be from about 5 wt.% To about 16 weight. % and more specifically, from about 8 wt.% to about 12 wt.%. The amylose content of starch is from 0 wt.% To about 70 wt.% And more specifically from about 20 wt.% To about 30 wt.%.

 A plasticizer can be added to the starch polymer to lower the glass transition temperature of the produced starch filaments and thereby increase their flexibility. In addition, the presence of a plasticizer can reduce the viscosity of the melt, which, in turn, contributes to the process of extrusion of the melt. A plasticizer is an organic compound having at least one hydroxyl group, such as, for example, a polyol. Sorbitol, mannitol, D-glucose, polyvinyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, sucrose, fructose, glycerin and mixtures thereof proved to be suitable. Examples of plasticizers are sorbitol, sucrose and fructose in amounts of from about 0.1 wt.% To about 70 wt.%, More specifically from about 0.2 wt.% To about 30 wt.% And even more specifically from about 0.5 wt.% up to about 10 wt.%.

 Other additives can usually be incorporated into the starch polymer, such as a substance for improving technological properties and additives for modifying the physical properties of extruded starch filaments, for example, elasticity, tensile strength in the dry state and strength in the wet state. Additives are usually present in amounts of from 0.1 wt.% To 70 wt.% Calculated on the content of non-volatile substances (meaning that this amount is calculated minus volatile substances, such as water). Examples of additives include, but are not limited to, urea, urea derivatives, intermolecular bonding agents, emulsifiers, surfactants, lubricants, proteins and their alkali metal salts, biodegradable synthetic polymers, waxes, low temperature synthetic thermoplastic polymers melting, tackifying resins, fillers and mixtures thereof. Examples of biodegradable synthetic polymers include, but are not limited to, polycaprolactone, polyoxybutyrates, polyoxyvalerates, polylactides, and mixtures thereof. Other additives include optical brighteners, antioxidants, flame retardants, dyes, pigments and fillers. It may be useful for the present invention to introduce an additive containing urea in amounts of from 0.5 wt.% To 60 wt.% In the starch composition.

 Suitable excipients for use in this case include gelatin, vegetable proteins such as corn protein, sunflower protein, soy protein, cotton seed protein; water-soluble polysaccharides, such as alginates, carrageenans, guar gum, agar, gum arabic and the corresponding resins, and pectin; and water-soluble cellulose derivatives, such as, for example, alkyl cellulose, hydroxyalkyl cellulose, carboxymethyl cellulose, etc. In addition, water-soluble synthetic polymers such as, for example, polyacrylic resins, polyacrylic esters, polyvinyl acetates, polyvinyl alcohols, polyvinyl pyrrolide etc. can be used.

 Additionally, lubricants may be added to improve the rheological properties of the starch material during processing by the method of the present invention. The lubricants may be animal or vegetable fats, preferably in their hydrogenated form, especially those that are solid at room temperature. Additional lubricants include monoglycerides and di-glycerides, as well as phosphatides, especially lecithin. A sizing agent that contains a monoglyceride, glycerol monostearate is considered useful for the present invention.

 Other additives, including inorganic fillers, such as, for example, oxides of magnesium, aluminum, silicon and titanium, can be introduced as inexpensive fillers or substances to improve technological properties. In addition, inorganic salts, including alkali metal salts, alkaline earth metal salts, phosphates, etc., can be used as substances for improving technological properties.

 Other additives may be desirable depending on the intended specific end use of the product. For example, for products such as toilet paper, disposable wipes, thin soft paper for handkerchiefs, and other similar products, wet strength is a desirable property. Thus, it is often desirable to add crosslinking agents known to the prior art as resins to the “starch polymer” to impart “moisture resistance”.

 A general description of the types of wet strength resins used in papermaking can be found in the monograph TAPPI, ordinal 29, Wet Strength in Paper and Paper-board, Technical Association of the Pulp and Paper Industry (New York, 1965). here by reference. The most useful resins to give moisture resistance are inherently cationic in nature. Of the polyamide epichlorohydrin resins, the cationic polyamide amine epichlorohydrin resins proved to be the most useful for imparting moisture resistance. Suitable types of such resins are described in US Pat. One source for the sale of useful polyamideepichlorohydrin resin is Hercules, Inc., Wilmington, pc. Delaware, USA, which sells such resins under the Kimene trademark.

 Glyoxylate polyacrylamide resins have also been found to be useful as moisture resins. These resins are described in US Pat. One source for the sale of glyoxylate polyacrylamide resins is Siteec Company, Stanford, pc. Connecticut, USA, which sells one such resin under the trademark "Pares 631 NS."

 Another water-soluble cationic resins that can be used with this invention are urea-formaldehyde and melamine-formaldehyde resins. More common functional groups of these multifunctional resins are nitrogen-containing groups, such as, for example, amino groups and methyl groups attached to nitrogen. Resins of the polyethyleneimine type may also be useful in the present invention. In addition, other resins can be used in the present invention to provide moisture resistance, such as, for example, Caldas (manufactured by Japan Carlite) and Cobond 1000 (manufactured by National Stach & Cam Company).

 For the present invention, one substance that causes the formation of intermolecular bonds is the Kimene resin, which provides moisture resistance, used in amounts of from about 0.1 wt.% To about 10 wt. and more specifically, from about 0.1 wt.% to about 3 wt.%.

 For the manufacture of starch filaments suitable for the flexible structure 100 according to the present invention, the starch composition must exhibit a certain rheological behavior during processing, for example, have a certain tensile viscosity and a certain capillary number. Of course, the type of treatment (for example, melt spinning with high-speed gas flow, electrospinning, etc.) may dictate the necessary rheological properties of the starch composition.

Stretch or stretch viscosity (η _e ) is associated with the melt extensibility of the starch composition and is especially important in tensile processes, for example in the manufacture of starch filament. Depending on the type of deformation of the composition, the tensile viscosity can be of three types: viscosity under uniaxial or simple tension, viscosity under biaxial tension, and shear viscosity with pure shear. Uniaxial tension viscosity is especially important in uniaxial tension processes, such as mechanical drawing, melt spinning, gas spinning, spun and electrospinning. The other two types of tensile viscosity are important for biaxial stretching or molding processes in the manufacture of films, foamed materials, sheets or parts.

 For conventional thermoplastics used to form fibers, such as polyolefins, polyamides and polyesters, there is a strong correlation between tensile and shear viscosity of these conventional thermoplastic materials and mixtures thereof. Thus, the formability of the material can simply be determined by shear melt viscosity, even if formability is a property controlled mainly by the melt viscosity in tension. This correlation is quite reliable, so that in the fiber industry, the selection and formulation of melt-formed materials rely on shear viscosity of the melt. Tensile melt viscosity is rarely used as a means of selection in industry.

 Therefore, as unexpectedly discovered, the starch compositions of the present invention do not necessarily show such a correlation between shear and tensile viscosities. In this case, starch compositions show a melt flow regime typical of a non-Newtonian fluid, and as such exhibit strain curing, i.e. tensile viscosity increases with increasing tensile or deformation.

 For example, when a high molecular weight polymer selected according to the present invention is added to the starch composition, the shear viscosity of the composition remains relatively unchanged or even slightly reduced. Based on ordinary common sense, one should assume a reduced ability of the starch composition to process in the melt and not suggest its suitability for processes with stretching the melt. However, as it turned out unexpectedly, the starch composition in this case shows a significant increase in tensile viscosity when even a small amount of high molecular weight polymer is added. Therefore, the starch composition in this case, as it turned out, has an increased tensile viscosity and is suitable for processes with stretching of the melt, especially for processes of molding with the pulling of a gas stream, spun and electrospinning.

 A starch composition that has a shear viscosity measured by the test method described below is less than about 30 Pascal second (Pa • s), more specifically from about 0.1 Pa • s to about 10 Pa • s, suitable for those described here processes of drawing out of the melt. In this case, some starch compositions may have a low melt viscosity, so that they can be mixed, transported or otherwise processed in traditional polymer processing equipment commonly used for viscous fluids, such as in a stationary mixer equipped with a metering pump and die. The shear viscosity of the starch composition can be effectively changed by the molecular weight and molecular weight distribution of starch, the molecular weight of the high molecular weight polymer and the amount of plasticizers and / or solvents used. It is believed that reducing the average molecular weight of starch is an effective way to lower the shear viscosity of the composition.

 In one embodiment of the present invention, melt-processed starch compositions have a tensile viscosity ranging from about 50 Pa • s to about 20,000 Pa • s, more specifically from about 100 Pa • s to about 15,000 Pa • s, more specifically - from about 200 Pa • s to about 10,000 Pa • s, more specifically from about 300 Pa • s to about 5000 Pa • s and even more specifically from about 500 Pa • s to about 3,500 Pa • s temperature. Tensile viscosity is calculated by the method described in the Test Methods section below.

 The rheological properties of the starch composition (including tensile viscosity) can be influenced by many factors. These factors include, but are not limited to: the amount and type of polymer components used, molecular weight and molecular weight distribution of components, including starch and high molecular weight polymers, amylose content in starch, amount and type of additives (e.g. plasticizers, diluents, substances to improve technological properties), the type of processing (for example, molding by drawing a stream of gas or electroforming) and processing conditions, such as temperature, pressure, strain rate and relative humidity, and, in the case of non-Newtonian materials - prehistory and deformation (ie, the time variation of deformation..). Some materials may be strain-hardening, i.e., their tensile viscosity increases with increasing strain. This is apparently caused by the stretching of an intertwined polymer network. If the stress is removed from the material, then the stretched twisted polymer network relaxes to a lower level of deformation depending on the relaxation time constant, which is a function of temperature, the molecular weight of the polymer, the concentration of solvent or plasticizer, and other factors.

 The presence and properties of high molecular weight polymers can have a significant effect on the viscosity of the starch composition in tension. High molecular weight polymers useful for increasing the melt extensibility of the starch composition used in the present invention are typically substantially linear high molecular weight polymers. In addition, high molecular weight polymers that are substantially compatible with starch are the most effective polymers for increasing the melt extensibility of a starch composition.

 As it turned out, starch compositions suitable for melt stretching processes typically increase their tensile viscosity by at least 10 times when a selected high molecular weight polymer is added to the composition. Typically, starch compositions, when a selected high molecular weight polymer is added to them, increase their tensile viscosity by about 10 - about 500 times, more specifically, by about 20 - about 300 times, and even more specifically - by about 30 - about 100 times. The greater the amount of high molecular weight polymer, the greater the increase in tensile viscosity. A high molecular weight polymer can be added to control tensile viscosity up to 200-2000 Pa • s with a Henki strain of 6. For example, polyacrylamide having a molecular weight (MM) of 0.001% -0.1% may be added to the starch composition from 1 million to 15 million.

 The tensile starch composition can also be affected by the type and amount of starch used. In general, as the amylose content of starch decreases, the tensile viscosity increases. In addition, with an increase in the molecular weight of starch in the above ranges, in general, tensile viscosity also increases. Finally, with an increase in the amount of starch in the compositions, in general, tensile viscosity increases. (On the contrary, with an increase in the amount of additive in the compositions, in general, the tensile viscosity decreases).

The temperature of the starch composition can significantly affect the viscosity of the starch composition in tension. For the purposes of the present invention, all conventional means for controlling the temperature of the starch composition can be used if they are suitable for use with this process. For example, in embodiments of the invention in which starch fibers are made by extrusion through a die, the temperature of the die can have a significant effect on the tensile viscosity of starch compositions extruded through it. The temperature of the starch composition may be from about 20 ^o C to about 180 ^o C, more specifically from about 20 ^o C to about 90 ^o C and more specifically from about 50 ^o C to about 80 ^o C. It should be noted that the presence or absence particulate matter in a starch composition may affect its required temperature. To characterize the flow regime under tension, the Trauton ratio can be used. The Trauton ratio is defined as the ratio between the tensile viscosity (η _e ) and the shear viscosity (η _s ):
Tr = η _e (ε ^• , t) / η _s
where the tensile viscosity (η _e ) depends on the strain rate (ε ^• ) and time (t). For a Newtonian fluid, the Trauton ratio under uniaxial tension has a constant value of 3. For a non-Newtonian fluid, as, for example, in this case of starch compositions, the tensile viscosity depends on the strain rate (ε ^• ) and time (t). It has also been found that melt-processing compositions of the present invention typically have a Trauton ratio of at least 3. When measured at a processing temperature and a tensile speed of 700 s ⁻¹ , the Trauton ratio for a Henki strain of 6 usually ranges from about 10 to about 5000, more specifically from about 20 to about 1000, and more specifically, from about 30 to about 500.

In addition, as established by the applicants, in embodiments of the invention in which starch filaments are made by extrusion through a die, the capillary number (Ca) of the starch composition when it passes through the die is important for the melt processability. A capillary number is a number expressing the ratio of the forces of internal friction in a fluid to the forces of surface tension. If the forces of internal friction are not much greater than the forces of surface tension, then near the exit of the die the trickle of liquid will break into drops, which is usually called "spraying". The capillary number is calculated by the following equation:
Ca = (η _s • Q) / (π • r ² • σ)
where (η _s ) is the shear viscosity in pascal seconds measured at a shear rate of 3000 s ^-1 ; Q is the volumetric flow rate of the fluid through the capillary die in m ³ / s; r is the radius of the capillary die in meters (for non-circular holes, an equivalent diameter / radius can be used); and σ is the surface tension of the fluid in newtons per meter.

 Since, as described above, the capillary number is related to shear viscosity, it is similarly affected by the same factors that affect shear viscosity. As used herein, the term “characteristic” in connection with a capillary number indicates that external factors, such as, for example, the presence of an electric field, do not affect the properties of the starch composition. The term "effective" indicates that external factors, such as, for example, the presence of an electric field, influence the properties of a starch composition.

 In one embodiment of the present invention, starch compositions capable of melt processing, when passing through a die, have a characteristic capillary number of at least 0.01 and an effective capillary number of at least 1.0 in the absence of the electric field, the capillary number should be greater than 1, for stability, and preferably greater than 5, for greater stability of the spinning thread. In the presence of an electric field, the repulsion of charges counteracts the influence of surface tension, so that the characteristic capillary number, measured without the presence of an electric charge, can be less than 1. When an electric potential is applied to the formed filament, the effective surface tension decreases and the effective capillary number increases based the following equations.

Although the capillary number can be expressed in various forms, the characteristic equation that can be used to determine the characteristic capillary number is:
Ca _inherent = η _s • ν / σ,
where Ca _inherent is the characteristic capillary number;
η _s — shear fluid viscosity;
v is the linear velocity of the fluid;
σ is the surface tension of the liquid.

 A representative sample suitable for the present invention had the following composition and properties.

Composition
Pure Gum 59 from National Stack Inc. - 40.00%
Deionized Water - 59.99%
Superflock N-300 LMW from Saytayk (high molecular weight polyacrylamide) - 0.01%
Operating temperature - 49 ^o C
Viscosity at a shear rate of 3000 s ^-1 - 0.1 Pa • s
Nozzle diameter - 0.0254 cm
Line speed - 0.236 m / s
Characteristic surface tension - 72 dyne / cm
As proven experimentally, in the absence of the influence of an electric charge on the liquid, this material will flow through the tip of the die to form small drops and then fall under the action of gravity in the form of separate drops. With an increase in the effect of the electric potential on the system, the droplets become smaller in size and begin to accelerate towards the grounding device. When the electric potential (25 kilovolts for this sample) reaches a critical value, a drop no longer forms on the die tip and a small continuous fiber is squeezed out of it. Thus, the applied electric potential now overcomes the surface tension forces, eliminating the capillarity violation mode of operation. The effective capillary number is now greater than 1. In laboratory experiments conducted with the described solution and experimental setup, substantially continuous fibers were obtained. The fibers were collected on a rarefied mesh in the form of a fiber mat. Analysis by optical microscopy showed that the fibers were continuous and had a diameter in the range of 3 to 5 microns.

 In some embodiments, the characteristic capillary number may be at least 1, more specifically from 1 to 100, more specifically from about 3 to about 50, and even more specifically from about 5 to about 30.

In this case, the starch composition is processed in a fluid state, which usually occurs at a temperature at least equal to or greater than its "melting point". Therefore, the processing temperature range is determined by the "melting temperature of the starch composition, which is measured by the test method described in detail here. In this case, the melting temperature of the starch composition is from about 20 ^o C to about 180 ^o C, more specifically from about 30 ^o C to about 130 ^{° C.,} and even more specifically, from about 50 ^{° C.} to about 90 ^° C. The melting temperature of the starch composition is a function of the amylose content of starch (with a higher amylose content, a higher melting temperature is required), containing water, plasticizer content and type of plasticizer.

 Exemplary biaxial stretching methods suitable for use with starch compositions are melt spinning, melt spinning and gas spinning. These methods are described in detail in US patent 4064605, issued December 27, 1977 in the name of Akiyama and others, US patent 4418026, issued November 29, 1883 in the name of Blackie and others, US patent 4855179, issued August 8, 1989 on the name of Baurland et al., U.S. Patent No. 4,909,976, issued March 20, 1990 to Cuculo et al., US Pat. in the name of Bühler et al. and US Pat.

 In FIG. 7, 8, and 9 schematically show an apparatus 10 for producing starch filaments suitable for the flexible structure 100 according to the present invention. The device 10 may be, for example, a single screw or double screw extruder, a displacement pump, or a combination thereof, known from the prior art. The starch solution may have a total water content, i.e., hydrated water plus added water in the range of about 5% to about 80%, and more specifically, in the range of about 10% to about 60%, based on the total weight of the starch material. The starch material is heated to elevated temperatures sufficient to form a pseudo-thermoplastic melt. This temperature is usually higher than the glass transition and / or melting temperature of the molded material. As is known in the art, pseudo-thermoplastic melts according to the present invention are polymer fluids whose viscosity depends on shear rate. Viscosity decreases with increasing shear rate, as well as with increasing temperature.

 To convert starch material into a pseudo-thermoplastic melt, the starch material can be heated in a confined space in the presence of a low concentration of water. The enclosed volume may be a closed vessel or a volume created by the sealing action of the feed material, as is the case in the worm of extrusion equipment. The pressures generated in the closed vessel will be the sum of the water vapor pressure and the pressure resulting from the compression of materials in the worm cylinder of the extruder.

To reduce the viscosity of the pseudo-thermoplastic melt, a chain breaking catalyst can be used that reduces molecular weight by breaking glucosidic bonds in starch macromolecules, which leads to a decrease in the average molecular weight of starch. Suitable catalysts include inorganic and organic acids. Suitable inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and boric acid, as well as acid salts of polybasic acids, for example NaHSO ₄ or NaH ₂ PO ₄ , etc. Suitable organic acids include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, oxalic acid, citric acid, tartaric acid, itaconic acid, succinic acid and other organic acids known in the art, including acidic salts of polybasic acids. In the present invention, hydrochloric acid, sulfuric acid and citric acid, including mixtures thereof, can be advantageously used.

The decrease in molecular weight of unmodified starch used can be about 2-5000 times and more specifically, 4-4000 times. The concentration of the catalyst is 10 ^-6 -10 ^-2 moles of the catalyst per mole of anhydro-glucose units and more specifically between 0.1 • 10 ^-3 -5 • 10 ^-3 moles of the catalyst per mole of anhydro-glucose starch units.

 7, a starch composition is supplied to an apparatus 10 for electroforming starch filaments used in the manufacture of the flexible structure 100 according to the present invention. The device 10 comprises a housing 11 designed and constructed to receive (arrow A) a starch composition 17 that can be contained therein and extruded (arrow D) into starch filaments 17a through a hole 14 of a die 13. An annular cavity 12 can be provided for circulation (arrows B and C) a heating fluid that heats the starch composition to a desired temperature. For heating the starch composition can be used other heating means known from the prior art, such as, for example, those that use electric heating, pulsed combustion, heating with water or steam, etc.

 The electric field can be applied directly to the starch solution, for example, through an electrically charged probe, or to the housing 11 and / or die 13. If desired, the forming element 200 can be electrically charged with an electric charge opposite to the charge of extruded starch filaments. On the other hand, the forming element may be grounded. The difference in electrical potentials can be from 5 kV to 60 kV, and more specifically, from 20 kV to 40 kV.

 Then, a plurality of extruded starch filaments can be deposited on the forming element 200, moving in the longitudinal direction of the PN at a certain distance from the device 10. This distance should be sufficient to allow stretching and then drying of the starch filaments and at the same time to maintain the potential difference between starch filaments emerging from the outlet 14 and the forming element 200. For this purpose, a stream of drying air can be supplied to the plurality of starch filaments to rotate d angle plurality of starch filaments. This would allow maintaining a minimum distance between the outlet 14 and the forming element 200 in order to preserve the potential difference between them and at the same time minimize the length of the part of the threads between the outlet and the forming element 200 in order to efficiently dry the threads. With this arrangement, the forming element 200 can be positioned at an angle to the direction of the filaments when they exit the outlet 14 (arrow D in FIG. 7).

Optionally, air can be used along with the electrostatic force to draw the filaments, creating a pulling force to thin or stretch the starch filaments before they are deposited on the forming member 200. Fig. 7a schematically shows an exemplary embodiment of a die equipped with one annular hole 15 covering the outlet hole 14, and three other holes evenly spaced at an interval of 120 ^o around the outlet 14, which are designed to supply air for drawing threads. Of course, with the present invention, other air supply methods for drawing yarns known in the art are possible.

 According to the present invention, starch filaments can have a size in the range of from about 0.01 decitex to about 135 decitex, more specifically from about 0.02 decitex to about 30 decitex, and even more specifically from about 0.02 decitex to about 5 decitex. Starch filaments can have various cross-sectional shapes, including, but not limited to, round, oval, rectangular, triangular, hexagonal, cross-shaped, star-shaped, irregular, and any combination thereof. As one of ordinary skill in the art understands, such diverse shapes can be formed by means of different shapes of the die outlets used to make starch filaments.

 In FIG. 10 schematically shows, but is not limited to, some possible cross-sectional shapes of starch filaments. The cross-sectional area of a starch filament is the area perpendicular to the main axis of the starch filament and outlined by the perimeter formed by the outer surface of the starch filament in the plane of the cross section. It is believed that the larger the surface area of the starch filament (per unit of length or weight), the greater the opacity of the flexible structure 10 containing starch filaments. Therefore, it is believed that maximizing the surface area of starch filaments by increasing their equivalent diameter may be useful for increasing the opacity of the resulting flexible structure 100 according to the present invention. One way to increase the equivalent diameter of starch filaments is to form starch filaments having non-circular, multifaceted cross-sectional shapes.

 In addition, starch filaments should not have a uniform thickness and / or cross-sectional area along the entire length of the filament or its part. For example, figure 10 schematically shows a segment of a starch filament having a different cross-sectional area along its length. Such different cross-sectional areas can be created, for example, by changing the pressure in the die or by changing at least one of the parameters (such as, for example, speed, direction, etc.) of the air for drawing the filaments or drying air during molding from melt with drawing by a gas stream or in a combined molding process with drawing by a gas stream and electrospinning.

 Some starch filaments may have “notches” located at certain intervals along the length of the filament or part thereof. It is believed that such changes in the cross-sectional area of starchy filaments along the length of the filament contribute to the flexibility of the filaments, improve the ability of the filaments to tangle into the fabricated flexible structure 100 and positively affect the softness and flexibility of the flexible structure 100 obtained. Notches or other useful irregularities in the starch filaments be formed by the contact of starch filaments with a surface having sharp edges or protrusions, as described below.

 The next stage of the method is the formation of the forming element 200. The forming element 200 may be made in the form of a cylinder with a corrugated surface (not shown) or other corrugated element, such as, for example, a belt or tape. The forming member 200 has a side 201 in contact with the threads and a back side 202 opposite the side 201 in contact with the threads. Under the influence of a differential pressure of the fluid (for example, a vacuum that may be present under the tape or inside the cylinder), the starch threads can be pressed into the relief of the forming element with the formation of distinguishable areas in the manufactured flexible structure.

 In the manufacturing process of the structure 100 according to the present invention, the starch filaments are deposited on the side 201 in contact with the filaments. The second side 202 is usually in contact with equipment, such as, for example, support rollers, guide rollers, a vacuum device, etc. required by a specific process. The side 201 contacting the threads has a three-dimensional relief of protrusions and / or depressions. Usually (although not necessarily) this topography is erratic and repetitive. This three-dimensional relief in contact with the threads of side 201 may comprise a substantially continuous relief (FIG. 4), a substantially semi-continuous relief (FIG. 5), a relief containing a plurality of individual protrusions (FIG. 5), or any combination thereof. When a plurality of starch filaments are deposited on the side 201 of the forming member 200 in contact with the filaments, the plurality of flexible starch filaments are at least partially adapted to the forming pattern of the forming member 200.

The forming element 200 may be a belt or tape that is macroscopically monoplane when lying in the reference plane XY, with Z being the direction perpendicular to the XY plane. In addition, the flexible structure 100 can be considered as macroscopically single-plane and lying in a plane parallel to the X-Y plane. Perpendicular to the X-Y plane is Z - the direction in which the thickness of the flexible structure 100 or the height of the various areas of the forming element 200 or the flexible structure is determined
100.

 If desired, the forming element 200 containing the tape may be made in the form of a press cloth. Suitable press cloth for use in accordance with the present invention can be made in accordance with technical solutions in US Pat. Nos. 5,549,790, issued August 27, 1996 to Feng; 5556509, issued September 17, 1996 in the name of Trokhan et al .; 5,580,423, issued December 3, 1996 to Ampulsky et al .; 5,609,725 issued March 11, 1997 to Feng; 5629052, issued May 13, 1997 in the name of Trokhan et al .; 5,637,194, issued June 10, 1997 to Ampulsky et al .; 5674663, issued October 7, 1997 in the name of McFarland et al .; 5,693,187, issued December 2, 1997 to Ampulsky et al .; 5709775, issued January 20, 1998 in the name of Trokhan et al .; 5776307, issued July 7, 1998 in the name of Ampulsky et al .; 5,795,440, issued August 18, 1998 to Ampulsky et al .; 5814190, issued September 29, 1998 in the name of Feng; 5817377, issued October 6, 1998 in the name of Trokhan et al .; 5846379, issued December 8, 1998 in the name of Ampulsky et al .; 5855739, issued January 5, 1999 to Ampulsky et al. And 5861082, issued January 19, 1999 to Ampulsky et al, descriptions of which are incorporated herein by reference. In another embodiment of the invention, the forming element 200 may be made in the form of a press cloth in accordance with technical solutions in US patent 5569358, issued October 29, 1996 in the name of Cameron.

 According to one main embodiment of the forming element 200, it comprises a polymer base 210 connected to a reinforcing element 250. The polymer base 210 may have a certain, pre-selected relief. For example, in FIG. 4 shows a substantially continuous base 210 having a plurality of through holes 220. In some embodiments, the reinforcing element 250 may be substantially permeable to the fluid. The reinforcing element 250, essentially permeable to the fluid, may consist of a woven mesh or perforated element, cloth or any combination thereof. The parts of the reinforcing element 250, combined with the holes 220 in the forming element 200, prevent the passage of starch filaments through the forming element and, thus, reduce the likelihood of holes in the resulting flexible structure 100. If it is undesirable to use a woven fabric for the reinforcing element 250, then the appropriate support and Strength for warp 210 can be achieved by means of a non-woven element, mesh, press cloth, or a plate or film having a plurality of through holes. A suitable reinforcing element 250 may be manufactured in accordance with US Pat. Nos. 5,496,624 issued March 5, 1996 to Stelges et al .; 5500277, issued March 19, 1996 to Trokhan et al. And 5566724, issued October 22, 1996 to Trokhan et al, descriptions of which are incorporated herein by reference.

 Various types of fluid permeable reinforcing member 250 are described in several US patents, for example 5,275,700 and 5,954,097, the disclosures of which are incorporated herein by reference. The reinforcing element 250 may be made of cloth, which is also called "press cloth" used in conventional paper production. The base 210 can be applied to a reinforcing element 250 as proposed in US Pat. Nos. 5,549,790, issued August 27, 1996 to Feng; 5556509, issued September 17, 1996 in the name of Trokhan et al .; 5,580,423, issued December 3, 1996 to Ampulsky et al .; 5,609,725 issued March 11, 1997 to Feng; 5629052, issued May 13, 1997 in the name of Trokhan et al .; 5,637,194, issued July 10, 1997 to Ampulsky et al .; 5674663, issued October 7, 1997 in the name of McFarland and others; 5,693,187, issued December 2, 1997 to Ampulsky et al .; 5709775, issued January 20, 1998 in the name of Trokhan et al .; 5,795,440, issued August 18, 1998 to Ampulsky et al .; 5814190, issued September 29, 1998 in the name of Feng; 5817377, issued October 6, 1998 to Trokhan et al., And 5846379, issued December 8, 1998 to Ampulsky et al, descriptions of which are incorporated herein by reference.

 On the other hand, the reinforcing element 250 may be impervious to the fluid. The fluid tightening reinforcing member 250 may be, for example, made of a polymeric material that is the same (or different from it) with the material used to make the base 210 of the forming member 200 according to the present invention; plastics any other suitable natural or synthetic material; or from any combination thereof. As one of ordinary skill in the art would recognize, the use of a fluid impermeable reinforcing member 250 will result in the mold 200 as a whole being also impermeable to the fluid. It is understood that the reinforcing element 250 may be partially permeable to the fluid and partially impermeable to it. Namely, some part of the reinforcing element 250 may be permeable to the fluid, and its other part is impermeable to it. The forming element 200 as a whole can be permeable, impermeable or partially permeable to the fluid. In the forming member 200, partially permeable to the fluid, only part or parts of the macroscopic portion or portions of the forming member 200 are partially permeable.

 If desired, a reinforcing element 250 with a jacquard weave can be used. Examples of jacquard weave tapes can be found in US Pat. Nos. 5,429,686, issued July 4, 1995 to Chiu et al .; 5,672,248 issued September 30, 1997 to Wendt et al .; 5746887, issued May 5, 1998 to Wendt and others, and 6017417, issued January 25, 2000 to Wendt and others, descriptions of which are incorporated here by reference with the limited purpose of showing the basic structure of the jacquard weave pattern. According to the present invention, it is contemplated to use a forming element 200, which has a jacquard weave pattern 201 in contact with the threads. Such a jacquard weave pattern can be used on the forming element 500, the forming element 200, the pressure surface, etc. As reported in the literature, the jacquard weave is especially useful when it is undesirable to compress or imprint the structure in the gap between the rolls, which usually occurs during transfer to a Yankee dryer cylinder.

 According to the present invention, one, several or all of the openings 220 of the forming member 200 may be “plugged” or “closed”, as described in US Pat. . As described in the patent just mentioned, polyurethane foam, rubber and silicone can be used to make the holes 220 impervious to the fluid.

 In the embodiment of the forming element 200 shown in FIG. 6, there are a plurality of hanging parts 219 extending (usually sideways) from the plurality of supporting parts 211. The hanging parts 219 are raised above the reinforcing element 250 to form free spaces 215 into which starch filaments can bend according to the present invention with the formation of the cantilever parts 129, as described above with reference to Fig.3. The forming element 200, containing the suspension parts 219, may have a multilayer structure formed by at least two layers (211, 212), connected together when the surface is located to the surface (Fig.6). Each of the layers may have a structure similar to that proposed in several of the above patents, which are incorporated herein by reference. Each of the layers (211, 212) may have at least one hole (220, FIG. 4, 4d) extending between the upper surface and the lower surface. The connected layers are arranged so that at least one hole in one layer overlaps (in a direction perpendicular to the common plane of the forming element 200) the base part of another layer forming the above-described suspension part 219.

 Another embodiment of a forming element containing a plurality of suspension parts can be manufactured by differential curing of a photosensitive resin layer or other curable material using a mask containing transparent and opaque portions. Opaque areas include areas with different opacity, for example, areas having relatively high opacity (opaque, such as black), and areas with relatively low opacity (i.e., having some opacity).

 When the curable layer having the thread receiving side and the opposite second side is subjected to curing radiation through a mask adjacent to the thread receiving side of the coating, the opaque portions of the mask protect the first portions from the curing radiation, preventing the first coating portions from curing to the entire thickness of the coating. Partially opaque mask portions only partially protect the second coating portions, allowing the curing radiation to cure the second portions to a predetermined thickness smaller than the coating thickness (starting from the thread receiving side of the coating towards its second side). The transparent areas of the mask leave the third areas of the coating unprotected, which allows the curing radiation to cure the third areas throughout the thickness of the coating.

Therefore, it is possible to remove uncured material from the partially formed forming element. The resulting cured base has a filament side 201 formed from the take-up side of the coating and a rear side 202 formed from the second side of the coating. The resulting base has a plurality of supports 211 comprising a rear side 202 and formed from third coating portions, and a plurality of suspension parts 219 comprising a side 201 in contact with the nonwoven material and formed from second coating portions. As discussed above, a plurality of supports can form a substantially continuous relief, a substantially semi-continuous relief, an intermittent relief, or any combination thereof. The suspension parts 219 extend at an angle (usually, but not necessarily, at an angle of about 90 ^° ) from the plurality of supports and are located at a distance from the rear side 202 of the resulting substrate with the formation of free spaces between the suspension parts and the rear side 201. Typically, when using the forming element 200, containing the reinforcing element 250, free spaces 215 are formed between the suspension parts 219 and the reinforcing element 250, as is best shown in Fig.6.

 In the next step, a plurality of pseudo-thermoplastic starch filaments are deposited on the side 201 of the forming element 200 in contact with the filaments, as shown schematically in Figs. the embodiment of the invention schematically shown in FIG. 7, where, after exiting the drawing device, the starch filaments 17a are deposited on the three-dimensional, contacting with the filaments side 201 of the forming element 2 00. In an industrial continuous process, the forming member 200 is an endless belt continuously moving in the longitudinal direction of the ST, as shown schematically in FIG. 7-9. Further, starch filaments can be connected to each other and mutually confused using various conventional methods. US Pat. No. 5,688,468, issued November 18, 1997 to Lu and incorporated herein by reference, provides a method and apparatus for producing a spun, non-woven fabric consisting of yarns of reduced diameter.

 In some embodiments, a plurality of starch filaments may initially be deposited, not on the forming element 10, but on the forming element 500, as shown schematically in FIG. 9. This step is optional and can be used to help achieve an even basic weight of a plurality of starch filaments across the entire width of the fabricated structure 10. According to the present invention, it is contemplated to use a forming member 500 comprising a wire mesh. In the exemplary embodiment of the invention shown in FIG. 9, the forming member 500 can move in the longitudinal direction, bypassing the rolls 50Ca and 500b. The forming element is permeable to the fluid, and below it is a device 550 for creating a vacuum and applying a differential pressure of the fluid to the plurality of starch filaments disposed thereon for their more or less uniform distribution over the entire receiving surface of the forming element 500.

 If desired, the forming element 500 can also be used to form various irregularities on starch filaments, especially on the surface of the filaments. For example, the thread receiving surface of the forming element may comprise a number of sharp edges (not shown) configured to imprint on the still relatively soft starch filaments located on them to form cuts (shown schematically in FIG. 11) or other irregularities on the starch filaments, which may be useful for fabricated flexible structure 100, as described above.

 In the embodiment of the invention shown in FIG. 9, a plurality of threads can be transferred from the forming member 500 to the forming member 200 by any conventional means known in the art, for example, by means of a negative pressure generating apparatus 600 sufficient to allow the plurality of starch filaments located on the forming element 500 was separated from it and adhered to the forming element 200.

 It is assumed that during the continuous manufacturing process of the flexible structure 100, the forming element 200 may have a linear speed that is less than the linear speed of the forming element 500. The use of such a difference in speeds at the transfer point is well known in papermaking and can serve for the so-called "microcontraction", which is generally believed to be effective in applying to low density wet webs. "Microcontraction in the wet state" is described in detail in US Pat. No. 4,405,597, the contents of which are incorporated herein by reference in order to describe the principal mechanism of microcontraction. In short, wet micro-contraction consists in transferring a web having a low fiber density from a first element (such as a forming element) to a second element (such as, for example, a loop of a fabric with a rare weave) moving slower than the first element. It is now believed that if starch filaments can be molded and a plurality of starch filaments can remain in a sufficiently flexible state by the time of transfer from a comparatively slower moving support (such as forming element 500) to a relatively faster moving support (such as forming element 200), it is possible to micro-reduce many starch filaments efficiently, thereby previously reducing the fabricated flexible structure 100. The speed of the forming element 200 can be from about 1% up to about 25% more than the speed of the forming element 500.

In FIG. 9A shows an embodiment of the method according to the present invention, in which starch filaments can be deposited on the forming element 200 at an angle A, which may be from 1 ^o to 89 ^o and more specifically from about 5 ^o to about 85 ^o . It is believed that this option is particularly useful when using the forming element 200 having hanging parts 219. Such deposition of starch filaments 17a "at an angle" to the forming element 200 allows free spaces 215 to be formed between the hanging parts 219 and the reinforcing element 250, more accessible for long and flexible starch filaments 17a, and facilitates easier filling of empty spaces 215 with starch filaments. In FIG. 9A, starch filaments 17a are deposited on the forming element 200 in two stages, so that both types of free filaments of the spaces 219 - front free spaces 215a in the direction of movement and rear free spaces 215b in the direction of movement - could be useful in the deposition of threads at an angle to the forming element 200. Depending on the specific geometry of the forming element 200, especially the geometry and / or orientation of its suspended parts 219, the initial angle A may be equal to or different from the subsequent angle B.

 Once a plurality of starch filaments is deposited on the side 201 of the forming element 200 in contact with the filaments, the plurality of filaments is at least partially adapted to its three-dimensional relief. In addition, various means can be used to cause or facilitate the adaptation of the starch filaments to the three-dimensional relief of the forming element 200. One method is to apply a pressure drop of the fluid to the plurality of starch filaments. This method can be especially useful when the forming member 200 is permeable to the fluid. For example, underneath the rear side 202 of the fluid-permeable forming member 200, a device 550 may be provided for applying vacuum to the forming member 200 and thus to the plurality of starch filaments disposed thereon (FIG. 8). Under the influence of rarefaction, some of the starch filaments can deviate into the openings 220 and / or free spaces 215 of the forming element 200 and otherwise adapt (fit snugly) to its three-dimensional relief.

 It is contemplated that all three regions of the flexible structure 100 may have substantially equivalent base weights. By bending a portion of the starch filaments into the openings 220, it is possible to reduce the density of the resulting pillows 120 compared to the density of the first imprinted areas 110. The areas 110 that are not bent into the openings 220 can be impressed by the compression of the flexible structure in the gap between the rolls. When imprinted, the density of the imprinted regions 110 increases compared to the density of the pillows 120 and the density of the third region 130. The density of the regions 110 not bent into the holes 220 and the density of the third region 130 is higher than the density of the pillows 120. The third region 130 is likely to have a density intermediate between the densities of imprinted areas 110 and pillows 120.

 Referring again to FIG. 1A, in which the flexible structure 100 according to the present invention can be considered as having three different densities. The area with the highest density will be the high-density imprinted area 110. The printed area 110 in position and geometry corresponds to the base 210 of the forming element 200. The area with the lowest density of the flexible structure 100 is the area with cushions 120, in position and geometry corresponding to the holes 220 of the forming element 200. The third area 130, corresponding to the recesses 230 in the forming element 200, will have a density intermediate between the densities of the pillows 120 and the imprinted area 110. The "recesses" 230 are substrate surfaces that have Z- a directional vector component extending from the take-up side 201 of the forming member 200 towards its rear side 202. The recesses 230 do not extend through the entire base 210, as the holes 220 do. Thus, the difference between the recess 230 and the holes 220 is believed to be in that the hole 220 is a through hole in the base 210, while the recess 230 is a blind hole, a groove, a deep notch or groove in the base 210.

 Three regions of the structure 100 according to the present invention can be considered as located at three different heights. As used herein, the term "height of the region" means its distance from the reference plane (i.e., the X-Y plane). For convenience, the reference plane can be considered horizontal, while the distance along the height from the reference plane is vertical. The height of a particular area of the starch filament structure 100, as is well known in the art, can be measured using a non-contact measuring device suitable for such purposes. A particularly suitable measuring device is a non-contact laser displacement sensor having a beam size of 0.3 x 1.2 millimeters in the range of 50 millimeters. Suitable non-contact laser displacement sensors are sold by Idec Company in the form of MX1A / B models. Alternatively, a contact device with a measuring tip known in the art can be used to measure different heights. Such a device with a measuring tip is described in US patent 4330981, which is issued in the name of Krastens and the contents of which are incorporated herein by reference. The structure 100 according to the present invention is placed on the reference plane so that the imprinted area 110 is in contact with the reference plane. The pillows 120 and the third region 130 extend vertically from the reference plane. When using the forming element 200 with different depths or heights of its three-dimensional relief, schematically shown in figa, areas 110, 120 and 130 can also be formed with different heights. Such a three-dimensional profile with different depths / heights can be obtained by grinding the pre-selected parts of the forming element 200 to reduce their height. In addition, the forming element 200, consisting of a curable material, can be made using a three-dimensional mask. Using a three-dimensional mask having different depths / heights of its recesses / protrusions, it is possible to form a corresponding base 210, also having different heights. For the above purposes, other conventional methods of forming surfaces with different heights can be used.

 In order to reduce the negative effect of the sudden application of a differential pressure of the fluid by means of a negative pressure device 550 (FIGS. 8 and 9) or a gripper for creating a negative pressure 600 (FIG. 9), which could force a certain number of threads or their parts to pass through forming element 200 and, thus, lead to the formation of so-called pin holes in the resulting flexible structure, the back side of the forming element can be "textured" to form microscopic surface irregularities. These surface irregularities may be useful in some embodiments of the forming element 200, since they prevent the formation of a vacuum seal between the rear side 202 of the forming element 200 and the surface of the paper equipment (such as the surface of the vacuum device), thereby creating a "leak" between them and thus mitigating the undesirable effects of applying a vacuum during the manufacturing process of the flexible structure 100 according to the present invention with the passing of land nogo air therethrough. Other ways to create such a leak are described in US patent 5718806, 5741402, 5744007, 5776311 and 5885421, descriptions of which are incorporated herein by reference.

 In addition, a leak can be created during the manufacture of the so-called forming element. "methods using various light transmission" described in US patent 5624790, 5554467, 5529664, 5514523 and 5334289, descriptions of which are incorporated herein by reference. The forming element can be made by coating a photosensitive resin on a reinforcing element that has opaque parts, and then irradiating the coating with light with an activating wavelength through a mask having transparent and opaque portions, and also through the reinforcing element.

 Another way to form surface irregularities on the back side of the forming element is to use a textured forming surface or a textured barrier film, as described in US Pat. Nos. 5,364,504, 5,260,171 and 5,098,522, the descriptions of which are incorporated herein by reference. A forming element can be made by casting a photosensitive resin onto and through the reinforcing element as it moves along a textured surface, and then exposing the coating to light with an activating wavelength through a mask that has transparent and opaque portions.

 To facilitate the sagging of multiple threads into the three-dimensional relief of the forming element, tools such as a device 550 for applying a vacuum (i.e., negative pressure less than atmospheric pressure) to the multiple threads through the fluid-permeable forming element 200 or a fan can be used. (not shown) for applying positive pressure to multiple threads.

 In addition, FIG. 9 schematically illustrates an optional step of the method according to the present invention, in which a plurality of starch filaments is covered by a flexible sheet of material 800, which is an endless ribbon moving around the rollers 800a and 800b and in contact with a plurality of filaments. Thus, for a certain period of time, a plurality of threads are between the forming member 200 and the flexible sheet of material 800. The flexible sheet of material 800 may have less breathability than the forming member 200, and in some embodiments, may be airtight. The application of the pressure differential of fluid P to the flexible sheet causes deflection of at least a portion of the flexible sheet in the direction (and in some cases inward) of the three-dimensional relief of the forming element 200, which causes the starch filaments to be closely adjacent to the three-dimensional relief of the forming element 200. In the patent US 5893965, the description of which is incorporated herein by reference, describes the basic design of the equipment and how to use a flexible sheet of material.

 In addition to or as an alternative to the pressure drop of the fluid, mechanical pressure can also be used to promote the formation of a three-dimensional microscopic relief on the flexible structure 100 according to the present invention. Such mechanical pressure can be generated by any suitable pressing surface, for example, a roller surface or a tape surface. FIG. 8 shows two exemplary embodiments of a pressure surface. To make the starch filaments located on the forming member 200 more fully adapt to its three-dimensional relief, two or more pressure rollers 900a and 900b, as well as 900c and 900d, can be used. If desired, the pressure generated by the pressure rollers can be made to vary in magnitude, for example, the pressure created between the rollers 900c and 900d may be greater than the pressure between the rollers 900a and 900b. Alternatively, or in addition to this, an endless pressure strip 950 moving around the rollers 950a and 950b can be pressed against a portion of the take-up side 201 of the forming element to compress the flexible structure 100 between the pressure tape and the forming element.

 The pressure surface may be smooth or have a three-dimensional relief. In the latter case, the pressing surface can be used as an embossing device to form a three-dimensional microrelief of the protrusions and / or recesses in the flexible structure 100 in cooperation with or independently of the three-dimensional relief of the forming element 200. In addition, the pressing surface can be used for applying various additives, for example, softeners, and printing ink to the flexible structure 200 being produced. For direct or indirect application of various additives to the flexible structure 200 being produced, conventional methods such as, for example, a dyeing roller 910 or spray device (or spray) 920.

 Optionally, the structure 100 can be subjected to preliminary reduction, known from the prior art. Preliminary reduction can be carried out by creping the structure 100, descending from a solid surface, more specifically from a cylinder, such as, for example, cylinder 290, schematically shown in Fig.9. The creping is carried out with a scraper 292, well known in the art. Creping can be carried out according to the method described in US patent 4919756, which was issued April 24, 1992 in the name of Sodai and the description of which is incorporated herein by reference. As an alternative or addition, pre-reduction can be accomplished by micro-reduction described above.

 The flexible structure 100, which has undergone preliminary reduction, is usually more tensile in the longitudinal direction than in the transverse direction, and is easily bent along the fold lines that are formed as a result of the preliminary reduction process and which usually extend in the transverse direction, i.e., in width flexible structure 100. A flexible structure 100 that has not been creped and / or otherwise pre-contracted is considered to be within the scope of the present invention.

 Using the flexible structure 100 according to the present invention, various materials can be manufactured. The resulting materials can be used in filters for air, oil and water; vacuum cleaner filters; furnace filters; face masks; coffee filters; tea bags or coffee portioned packaging; heat and sound insulating materials; non-woven materials for disposable hygiene products, such as diapers, panty liners and urinary incontinence products; biodegradable textile fabrics for improved moisture absorption and softness of clothing, such as microfibre or gas-permeable fabrics; an electrically charged, structured web for collecting and removing dust; Reinforcements and webs for hard paper, such as brown paper, writing paper, newsprint, corrugated paper and webs for thin paper, such as toilet paper, towel paper, tissue paper and tissue paper; medical supplies, such as surgical sheets, wound dressings, bandages, skin patches, and self-dissolving suture materials; and dental products, such as filaments for cleaning interdental spaces and bristles of toothbrushes. In addition, the flexible structure may contain deodorants, termite repellents, insecticides, rodenticides and similar substances for special applications. The resulting material absorbs water and oil and can find application in the cleaning of spilled oil or water and in the controlled retention and release of water when used in agriculture or horticulture. The resulting starch filaments or fibrous materials can also be incorporated into other materials, such as sawdust, wood pulp, plastics or concrete to form composite materials that can be used as building materials, for example, for walls, support beams, extruded panels , internal partitions and facing panels, and as a roofing tile; in other medical devices, such as casts, tires and spatulas for squeezing the tongue; and fireplace logs used for decorative purposes and / or for burning.

Test methods
A. Shear viscosity
The shear viscosity of the composition is measured using a capillary rheometer (Rheograph 2003 model manufactured by Goetfert). Measurements are made using a capillary die with a diameter D of 1.0 mm and a length L of 30 mm (i.e., L / D = 30). The die is attached to the lower end of the cylinder, which is maintained at a test temperature (t) in the range of 25 ^{° C.} to 90 ^° C. A sample of the composition that is preheated to the test temperature is loaded into the cylinder portion of the rheometer, which it substantially fills (use about 60 grams of sample). The cylinder is maintained at a certain test temperature (t). If air bubbles rise to the surface after loading, then before testing the sample is compacted to remove trapped air from it. Program the movement of the piston to extrude the sample from the cylinder through the capillary die at a selected speed. When the sample exits the cylinder through the die, it experiences a pressure drop. The apparent shear viscosity is calculated from the pressure drop and flow rate of the sample through the capillary die. Then, a graph of the dependence of the logarithm of apparent viscosity during shear on the logarithm of the shear rate is plotted and, according to a power law, a graph of the dependence η = Kγ ^n-1 , where K is the material constant and γ is the shear rate. The shear viscosity of the composition noted in this case is extrapolated to a shear rate of 3000 s ⁻¹ using a power law.

B. Tensile viscosity
Tensile viscosity is measured using a capillary rheometer (Rheograph 2003 model manufactured by Goetfert). Measurements are carried out using a semi-hyperbolic die with an initial diameter (D _initial ) of 15 mm, a final diameter (D _final ) of 0.75 mm, and a length (L) of 7.5 mm.

Фильеру прикрепляют к нижнему концу цилиндра, выдерживаемого при постоянной температуре испытания (t), которая соответствует температуре, при которой необходимо перерабатывать крахмальную композицию. Температура испытания (температура переработки) - это температура, которая выше температуры плавления образца крахмальной композиции. Образец крахмальной композиции, предварительно нагретый до температуры фильеры, загружают в цилиндровую часть реометра, которую он по существу заполняет. Если после загрузки к поверхности поднимаются пузырьки воздуха, то перед проведением испытания расплавленный образец уплотняют для удаления из него захваченного воздуха. Программируют движение поршня для выдавливания образца из цилиндра через гиперболическую фильеру с заданной скоростью. При выходе образца из цилиндра через фильеру он испытывает падение давления. Кажущуюся вязкость при растяжении вычисляют по падению давления и скорости потока образца через фильеру по следующему уравнению:
Вязкость при растяжении = (дельта Р/скорость растяжения/Е_h)•10⁺⁵),
где вязкость при растяжении выражена в паскаль-секундах, дельта Р - падение давления в барах, скорость растяжения - скорость потока образца через фильеру в сек^-1 и Е_h - безразмерная деформация по Хенки. Деформация по Хенки - это деформация, зависящая от предыстории. Деформация, испытываемая элементом текучей среды в неньютоновской текучей среде, зависит от его кинетической предыстории, т.е.The semi-hyperbolic shape of the die is determined by two equations, where Z is the axial distance from the initial diameter and D (z) is the diameter of the die at a distance z from (D _initial ):

The die is attached to the lower end of the cylinder, maintained at a constant test temperature (t), which corresponds to the temperature at which the starch composition needs to be processed. Test temperature (processing temperature) is the temperature that is higher than the melting temperature of a sample of starch composition. A sample of the starch composition, previously heated to the die temperature, is loaded into the cylinder portion of the rheometer, which it essentially fills. If air bubbles rise to the surface after loading, then before the test, the molten sample is compacted to remove trapped air from it. Program the movement of the piston to extrude the sample from the cylinder through the hyperbolic die at a given speed. When the sample exits the cylinder through the die, it experiences a pressure drop. The apparent tensile viscosity is calculated by the pressure drop and the flow rate of the sample through the die according to the following equation:
Tensile viscosity = (delta P / tensile speed / E _h ) • 10 ⁺⁵ ),
where the tensile viscosity is expressed in pascal seconds, the delta P is the pressure drop in bars, the tensile speed is the sample flow rate through the die in sec ^-1 and E _h is the Hankey dimensionless deformation. Henki deformation is a history-dependent deformation. The deformation experienced by a fluid element in a non-Newtonian fluid depends on its kinetic history, i.e.

ε $\genfrac{}{}{0ex}{}{\text{t}}{\text{0}}$ = ∫ε ^• (t ′) ∂t ′
For this design, the Hankey strain (E _h ) is 5.99 and is determined by the following equation:
Eh = ln [(D _inltiai / D _final ) ² ]
As reported, the apparent tensile viscosity is a function of the tensile speed 250 ^-1 when using the power law. A detailed description of tensile viscosity measurements using a semi-hyperbolic die is provided in US Pat. No. 5,357,784, issued October 25, 1994 to Collier, and the description of which is incorporated herein by reference.

B. Molecular mass and molecular weight distribution
The weight average molecular weight (MM) and molecular weight distribution (MMP) of starch are determined by gel permeation chromatography (GPC) using a column with a mixed bed of filler. The device has the following parts:
Pump "Waters" model 600E.

 The regulator of the Waters model 600E.

 Autosampler "Waters" model 717 plus.

Column - Preparative thin-layer column with a mixed layer and with 20 μm gel particles (the molecular weight of the gel is from 1,000 to 40,000,000), having a length of 600 mm and an inner diameter of 7.5 mm
Detector - Waters differential model 410 refractometer for gel permeation chromatography, software - Waters Millennium program (registered)
The column is calibrated with Dextran reference materials having a molecular weight of 245000, 350,000, 480000, 805000 and 2285000. These Dextran reference substances are available from American Polymer Standards Corp. Mentor Ohio, USA Reference substances for calibration are prepared by dissolving the reference substances in the mobile phase to obtain a solution with a concentration of about 2 mg / ml. The solution is left alone overnight. Then it is carefully mixed and filtered through a pipette filter (5 μm Spartan-25 nylon membrane, available from VWR), using a pipette (5 ml, Norm Jack, available from VWR).

To obtain a starch sample, a mixture of 40 weight is first prepared. % starch in tap water and then heat the mixture until it is gelled. Then 1.55 g of the gelled mixture is added to 22 g of the mobile phase to form a 3 mg / ml solution, which is prepared by stirring for 5 minutes, placing the mixture for one hour in a thermostat with a temperature of 105 ^o C, removing the mixture from the thermostat and cooling it to room temperature. The solution is filtered using a pipette and a pipette filter as described above.

The autosampler takes a filtered standard or sample solution to wash the old test substances in 100 μl of the injection circuit and inject the test substance into the column. The column is kept at 70 ^° C. The sample eluted from the column is measured relative to the mobile phase background using a differential refractive index detector, maintained at 50 ^{° C.} and having a sensitivity range set to 64. The mobile phase is DMSO with 0.1 dissolved in it wt./about.% LiBr. The flow rate is set at 1.0 ml / min and in an isocratic mode (i.e., the mobile phase is constant during the experiment). Each reference substance or sample is tested three times by GPC and the results are averaged.

The molecular weight distribution (MMP) is calculated as follows:
MMP = weight average molecular weight / number average molecular weight.

D. Thermal properties
The thermal properties of these starch compositions are determined using the device "DSK-2910" for thermal analysis using differential scanning calorimetry calibrated with a standard substance with metallic indium, which, as reported in the chemical literature, has a melting point (initial) of 156.6 ^o C and heat melting 6.80 cal / g. The standard method for differential scanning calorimetry is used according to the manufacturer's instructions for use of the device. Due to the release of volatile substances (e.g. water vapor) from the starch composition during measurement by differential scanning calorimetry, a large volume cup equipped with an O-ring is used to prevent leakage of volatile substances from the sample cup. The sample and inert reference object (usually an empty cup) is heated at the same rate in a controlled environment. When a real or pseudo-conversion occurs in a sample, the differential scanning calorimetry device measures the heat flux to or from the sample in comparison with the heat flux to or from an inert reference object. The device is connected to a computer to control test parameters (for example, heating / cooling rate), collect, calculate and report data.

The sample is weighed in a cup, which is closed with a lid with an O-ring. A typical sample size is 25-65 milligrams. Place the closed cup in the device and program the computer to measure thermal properties as follows:
1) bring into equilibrium at 0 ^o C,
2) incubated for 2 min at 0 ^o C,
3) heated at a speed of 10 ^o C / min to 120 ^o C,
4) incubated for 2 min at 120 ^o C,
5) cooled at a speed of 10 ^o C / min to 30 ^o C,
6) bring into equilibrium at ambient temperature for 24 hours; the cup with the sample can be removed from the device for differential scanning calorimetry and placed for this length of time in a controlled environment at 30 ^o C,
7) return the cup with the sample to the device for differential scanning calorimetry and bring into equilibrium at 0 ^o C,
8) incubated for 2 minutes,
9) heated at a speed of 10 ^o C / min to 120 ^o C,
10) incubated for 2 min at 120 ^o C,
11) cooled at a rate of 10 ^o C / min and bring into equilibrium, and
12) remove the used sample.

 The computer calculates and reports the result of the thermal analysis in the form of the dependence of the differential heat flux (ΔН) on temperature or time. Typically, differential heat flux data is unified and reported based on weight (i.e. cal / mg). If the sample exhibits a phase pseudo-transformation, such as glass transition, then for easier determination of the glass transition temperature, a graph of the differential ΔН versus time / temperature can be used.

E. Solubility in water
A starch composition is prepared by mixing the components in a heating and mixing device until a homogeneous mixture is formed. The molten composition is cast into a thin film, distributing it over a Teflon sheet and cooling at ambient temperature. The film is then completely dried (i.e., until there is no water in the film / composition) in a thermostat at 100 ^° C. The dried film is then brought to equilibrium to room temperature. The film, brought into equilibrium, is crushed into small pieces.

Для определения растворимости образца композиции отвешивают 10 г измельченного образца в 250 мл химический стакан. Добавляют деионизированную воду до получения общего веса в 100 г. В течение 5 мин перемешивают образец и воду на тарелке для перемешивания. После перемешивания наливают, по меньшей мере, 2 мл перемешанного образца в пробирку центрифуги. Центрифугируют в течение 1 часа при 20000 g и 10^oС. Отбирают образующийся наверху слой центрифугированного образца и определяют показатель преломления. Растворимость образца в процентах вычисляют следующим образом:

Ж. Толщина
Перед испытанием пленочный образец выдерживают при относительной влажности 48%-50% и температуре 22^oС-24^oС, пока не будет достигнуто влагосодержание от около 5% до около 16%. Влагосодержание определяют посредством термогравиметрического анализа (ТГА). Для термогравиметрического анализа используют термогравиметрический анализатор ТГА2950 от компании "ТА инструментс". Согласно инструкциям изготовителя помещают образец и чашку в прибор и повышают температуру со скоростью 10^oС/мин до 250^oС. Влажность образца в процентах определяют, используя данные о потере веса и начальном весе следующим образом:

Предварительно кондиционированные образцы обрезают до размера больше, чем размер нагрузочного элемента. Используемый нагрузочный элемент представляет собой круг площадью 20,26 см².To determine the percentage of solids in the sample, 2-4 g of the crushed sample is placed in a pre-weighed metal cup, and the total weight of the cup and sample is recorded. The weighed cup and sample are placed for 2 hours in a thermostat with a temperature of 100 ^o C and then removed and immediately weighed. The percentage of solids is calculated as follows:

To determine the solubility of the sample, the composition is weighed 10 g of the crushed sample in a 250 ml beaker. Deionized water is added until a total weight of 100 g is obtained. The sample and water are mixed for 5 minutes on a mixing plate. After mixing, at least 2 ml of the mixed sample is poured into a centrifuge tube. It is centrifuged for 1 hour at 20,000 g and 10 ^° C. The layer of centrifuged sample formed at the top is taken and the refractive index is determined. The percent solubility of the sample is calculated as follows:

J. Thickness
Before the test, the film sample is maintained at a relative humidity of 48% -50% and a temperature of 22 ^o C-24 ^o C, until it reaches a moisture content of from about 5% to about 16%. Moisture content is determined by thermogravimetric analysis (TGA). For thermogravimetric analysis, a TGA2950 thermogravimetric analyzer from the company TA Instruments is used. According to the manufacturer's instructions, place the sample and the cup in the device and increase the temperature at a speed of 10 ^o C / min to 250 ^o C. The moisture content of the sample in percent is determined using data on weight loss and initial weight as follows:

Pre-conditioned samples are cut to a size larger than the size of the load element. Used load element is a circle with an area of 20.26 cm ² .

Place the sample on a horizontal flat surface and enclose it between this flat surface and the load element with a horizontal load surface, which is a circular surface with an area of 20.26 cm ² , after which a pressure of about 15 g / cm ^{2 is} applied to the sample. Thickness is the resulting gap between a flat surface and the load surface of the load element. Such measurements can be carried out using an electronic device for measuring thickness "VIR model II", available from the company "Tuing-Albert", Philadelphia, pc. Pennsylvania, USA The thickness is re-measured and recorded at least five times. The measurement result is recorded in miles (25.4 μm).

 The sum of readings recorded during thickness measurements is divided by the number of readings recorded. The result is recorded in miles (25.4 μm).

NOTATION
10 - a device for the manufacture of starch filaments; 11 - the housing of the device 10; 12 - a cavity for a heating fluid; 13 - die; 14 - outlet; 15 - air (ring) hole; 16 - air (separate) hole; 17 - starch composition; 18 - starch filaments; 100 - flexible structure; 110 are first areas of flexible structure 100; 120 are second regions of flexible structure 100 (cushion in some embodiments of the invention); 130 - third area of the flexible structure 100; 115 - essentially free spaces (pockets) in a flexible structure 100 (between the console parts and the first areas); 128 - convex part; 129 - console parts of a flexible structure 100; 200 - forming element; 201 - the receiving side of the forming element 200; 202 is the rear side of the forming element 200; 210 - the base; 211 - the first layer (in a multilayer structure); 212 - second layer (in a multilayer structure); 215 - free spaces between the suspension part 219 and the reinforcing element 250; 219 - suspended part; 220 - hole; 230 - recess; 250 - reinforcing element; 290 - (creping) cylinder; 292 - scraper; 500 - forming element; 550 - a device for creating a vacuum; 600 - removable device that creates a vacuum; 800 - a flexible sheet of material (hypobaric bending); 900a-900s - pressure rollers; 910 - dyeing roller; 920 - spray device (spray); 950 - pressure tape.

Claims (33)

 1. A flexible structure containing many starch filaments and having at least a first region and a second region, each of which has at least one common intensive property, at least one common intensive property of the first region the value differs from at least one general intensive property of the second region, while the general intensive property is selected from the group consisting of density, bulk, height, opacity, creping frequency, or any combination thereof.  2. The flexible structure according to claim 1, in which one of the first and second regions contains a substantially continuous grid, and the other of the first and second regions contains a plurality of distinct regions dispersed throughout the substantially continuous grid.  3. The flexible structure according to claim 1, in which at least one of the first region and the second region is a semicontinuous grid.  4. The flexible structure according to claim 1, which further comprises at least a third region having at least one intense property that is common but different in magnitude, with an intensive property of the first region and an intensive property of the second region, the general intensive property is selected from the group consisting of density, bulk, height, opacity, creping frequency, or any combination thereof.  5. The flexible structure according to claim 4, in which at least one of the first, second and third regions contains a substantially continuous grid.  6. The flexible structure according to claim 4, in which at least one of the first, second and third areas contains discontinuous sections.  7. The flexible structure according to claim 4, in which at least one of the first, second and third regions contains essentially semicontinuous sections.  8. The flexible structure of claim 4, wherein at least one of the first, second, and third regions comprises a plurality of discrete sections dispersed throughout a substantially continuous grid.  9. The flexible structure according to claim 1, in which when the structure is located on the horizontal reference plane, the first region defines the first height, and the second region extends outward from the first region, determining the second height, while the second height is greater relative to the horizontal plane than the first height.  10. The flexible structure according to claim 4, in which when the structure is located on the horizontal reference plane, the first region defines the first height, and the second region determines the second height and the third region determines the third height, and in which at least one of the first, second, and third heights differs from at least one of the other heights.  11. The flexible structure of claim 10, in which the second height is intermediate between the first height and the third height.  12. The flexible structure of claim 9, wherein the second region comprises a plurality of starch pillows, wherein at least some of the pillows comprises a protruding portion extending from the first height to a second height and a cantilever portion extending laterally from the protruding portion onto second height.  13. The flexible structure of claim 12, wherein the density of the starchy cantilever portion is intermediate between the density of the first region and the density of the protruding portion.  14. The flexible structure of claim 12, wherein the cantilever portion is raised above the first plane to form substantially free spaces between the first region and the cantilever portion.  15. The flexible structure according to claim 1, in which at least some of the many starch filaments have a size of from 0.001 to 135 decitex.  16. The flexible structure according to claim 1, in which at least some of the many starch filaments have a size of from 0.01 to 5 decitex.  17. A flexible structure comprising starch filaments and containing at least one substantially continuous mesh region and a plurality of discrete sections dispersed throughout the substantially continuous mesh region, wherein the substantially continuous mesh region has a relatively high density compared to the relatively low density of many individual sections.  18. A flexible structure comprising a plurality of starch filaments, the flexible structure being made by forming a plurality of starch filaments by melt spinning, dry spinning, wet spinning, electroforming, or any combination thereof, using a fluid permeable forming member containing a reinforcing element connected with a embossed polymer base having at least one through hole, a thread receiving side made with a relief for receiving a plurality of starch yarns, and the rear side opposite the thread receiving side, wherein the reinforcing element is located between the thread receiving side and at least a portion of the back side of the warp, and the thread receiving side contains a substantially continuous relief, a substantially semi-continuous relief, an intermittent relief or any combination thereof, the deposition of many starch filaments on the take-up side of the forming element, while many starch threads, at least partially tightly adhere to the relief of the take-up side of the base, is applied a differential pressure of the fluid to the plurality of starch filaments, thereby forming the first regions of the plurality of filaments supported by a corrugated base, and the second regions of the plurality of starch filaments deflected into at least one opening thereof and supported by a reinforcing element, and separating the plural starch filaments from the forming element, thereby forming a flexible structure comprising a first region and a second region. 19. A method of manufacturing a flexible structure containing starch filaments, which contains the following stages: (a) produce many starch filaments,
(b) using a forming element having a take-up side and a reverse side opposite to it, while the take-up side has a three-dimensional relief thereon, and (c) depositing a plurality of starch filaments onto the pick-up side of the forming element and forcing a plurality of starch filaments, at least partially fit snugly against the three-dimensional relief.  20. The method according to claim 19, wherein the step of using the forming element includes the use of a forming element, in which the three-dimensional relief of the take-up side comprises a substantially continuous relief, a substantially semi-continuous relief, a relief comprising a plurality of individual protrusions, or any combination.  21. The method according to claim 20, wherein the step of using the forming element includes the use of a forming element that comprises a polymer base connected to a reinforcing element.  22. The method of claim 20, wherein the step of using the forming member includes using a forming member that is breathable.  23. The method according to claim 20, wherein the step of using the forming element includes the use of a forming element having suspended parts.  24. The method according to item 23, wherein the step of using the forming element includes the use of a forming element formed by at least two layers connected together when the surface is located to the surface.  25. The method according to claim 19, wherein the step of depositing a plurality of starch filaments on the thread receiving side of the forming element and causing at least a partial snug fit of the plurality of starch filaments to its three-dimensional relief includes applying a pressure differential of the fluid to the plurality of starch filaments.  26. The method according to p. 19, which, in addition, contains the stage of compaction of selected parts of many starch filaments.  27. The method of claim 19, wherein the step of densifying selected parts of the plurality of starch filaments includes applying mechanical pressure to the plurality of starch filaments. 28. The method according to claim 19, wherein the step of depositing a plurality of starch filaments on the thread receiving side of the forming element includes depositing starch filaments at an acute angle thereto, wherein the acute angle is from about 5 ^° to about 85 ^° .  29. The method of claim 19, wherein the step of manufacturing the plurality of starch filaments comprises melt spinning, dry spinning, wet spinning, or any combination thereof.  30. The method according to clause 29, wherein the ratio of the length of the main axis of at least some starch filaments to the equivalent cross-sectional diameter perpendicular to the main axis of starch filaments is at least 100/1.  31. The method according to claim 19, wherein the starch filaments have a size of from about 0.001 decitex to about 135 decitex.  32. The method according to claim 19, which further comprises the stage of preliminary reduction of many starch filaments.  33. The method according to p, in which the preliminary reduction stage includes creping, micro-reduction, or a combination thereof.

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