JP2002201556A - Flexible structure comprising starch filament - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible structure comprising starch filaments, more specifically such a flexible structure having differential regions. SOLUTION: This flexible structure comprises a plurality of starch filaments, the structure comprising at least a 1st region and a 2nd region, and each of the 1st and 2nd regions has at least one common intensive property selected from the group consisting of density, basis weight, elevation, opacity, crepe frequency, and any combination thereof, wherein the common intensive property of the 1st region differs in value from that of the 2nd region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible structure including a starch filament, and more particularly to a flexible structure having a discrimination region.

[0002]

2. Description of the Related Art Cellulose fiber webs such as paper are known. Today, low density fiber webs are commonly used in paper towels, toilet paper, decorative paper, napkins, wet towels and the like. The great demand for paper products of this kind creates a demand for improved varieties and processes for these products. In order to meet this type of demand, paper companies need to balance the total cost of transporting products to consumers with the cost of machinery and materials.

[0003] In the operation of conventional papermaking equipment, wood cellulose fibers are repallated, beaten or refined to achieve a constant concentration of fiber hydrates in order to form a pulp water slurry. The preparation of paper products for use in tissues, towels, and sanitary products involves the preparation of a water slurry, followed by the dewatering of the slurry, while simultaneously forming the paper web by relocating the fibers in the slurry. Subsequent to dewatering, the web is processed to change its shape into a drying roll or sheet form, while at the same time converting into consumer packaging. The dehydration step and the implementation of the conversion operation require the use of various types of mechanical devices, and require a large amount of capital investment.

[0004] Another aspect of conventional papermaking operations involves the addition of other additives to the pulp for the purpose of achieving a certain finality. For example, additives such as a strength improving resin, a release surfactant, a softener, a pigment, a latex, a synthetic microsphere, a flame retardant, a dye, and a fragrance are frequently used for papermaking. The presence of additives at the wet end of the papermaking process is not only uneconomic if the portion of the additive not retained on the paper forms part of the factory wastewater, but also causes significant environmental pollution problems. It raises awkward issues for the company. The additives may be added to the paper web following the dewatering step by coating or absorption methods known to those skilled in the art. These methods usually require extra energy to dry the paper after application. In addition, in some cases, the coating system must be a solvent system, which adds to equipment costs and requires recovery of volatile materials to meet emission standards.

Various natural fibers other than cellulose as well as a variety of synthetic fibers have been used for papermaking, but all of these alternatives are expensive, have poor binding properties, are chemically incompatible, and are difficult to manufacture. Could not be a commercial alternative to cellulose. In various aspects of papermaking, starch fibers have been proposed as cellulose substitutes.
Commercial attempts to use this type of starch filament have not been successful. As a result, paper products are still produced exclusively from wood-derived cellulose components.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a flexible structure containing a long starch filament and a method for making the same.
In particular, the present invention provides a flexible structure comprising a plurality of starch filaments, wherein the structure has two distinctive reinforcing properties for improved strength, absorbency, and flexibility. Or more regions.

Further, according to the present invention, there is provided a method for producing a starch filament. The present invention particularly provides an electrospinning method for producing a plurality of starch filaments.

SUMMARY OF THE INVENTION A flexible structure includes a plurality of starch filaments. At least some of the plurality of starch filaments have a size of about 0.001 dtex to 135 dtex, more specifically 0.01 dtex to 5 dtex. The aspect ratio of the major axis length of at least some of the starch filaments to the equivalent diameter of the cross section perpendicular to the major axis of the starch filament is:
Aspect ratios greater than 100/1, more specifically greater than 500/1, even more specifically greater than 1000/1, and most specifically greater than 5000/1.

The structure includes at least a first region and a second region, each of the first and second regions having a density, base weight, elevation, opacity, crepe frequency, and It has at least one common intensive property selected from the group consisting of any combination. At least one common intensive property of the first area differs from at least one common intensive property of the second area in its value.

In one embodiment, one of the first and second regions includes a substantially continuous network, and the other of the first and second regions includes a plurality of dispersed throughout the substantially continuous network. Includes individual areas. In another embodiment, at least one of the first and second regions comprises a semi-continuous network.

[0011] The flexible structure further includes at least a third region, and the third region has at least one intensive characteristic whose value is common and different from the intensive characteristics of the first region and the second region. Have. In one embodiment, at least one of the first, second, and third regions may include a substantially continuous network. In other embodiments, at least one of the first, second, and third regions may include discrete or discontinuous areas. In still other embodiments, at least one of the first, second, and third regions may include a substantially semi-continuous area. In still other embodiments, at least one of the first, second, and third regions may include a plurality of discrete areas dispersed through a substantially continuous network.

[0012] Where the flexible structure includes a substantially continuous network region and a plurality of discrete areas dispersed through the substantially continuous network, the substantially continuous network region may include a plurality of regions. It may have a relatively high density compared to the relatively low density of individual areas. When the structure is arranged on a horizontal reference plane, the first region delimits the first ridge and the second region
The region extends outwardly from the first region to define a second ridge that is larger than the first ridge (relative to a horizontal reference plane).

When the structure in the embodiment including at least three regions is disposed on the reference plane, the first region is the first region.
The second area can define a second ridge, and the third area can define a second area.
The region can define a third ridge. At least one of the first,
The second and third ridges can be different from at least one of the other ridges, for example, the second ridge can be intermediate the first and third ridges.

[0014] In one embodiment, the second region includes a plurality of starch pillows, each pillow extending from a first ridge to a second ridge, and laterally extending from the dome to a second ridge. It may include a cantilever wing that extends in a direction. The density of the starch cantilever wings can be equal to or different from the density of at least one of the first region and the density of the dome, or can be intermediate between the density of the first region and the density of the dome. The cantilevered wing is typically raised from a first plane to form a substantially void space between the first region and the cantilever.

The flexible structure may comprise a plurality of starch filaments formed by melt spinning, dry spinning, wet spinning, electrospinning, or any combination thereof; a structure containing a plurality of starch filaments thereon. Providing a molded member having a filament receiving side; depositing a plurality of starch filaments on the molded member, wherein at least a portion of the plurality of starch filaments conforms to the pattern of the molded member; and forming a plurality of starch filaments. Remove from the component;
It can be manufactured by a process.

During the step of depositing the starch filament,
A step of adapting at least a part of the plurality of filaments to the filament receiving side of the molded member with respect to the three-dimensional pattern of the molded member is included. This step can be performed, for example, by applying a hydraulic pressure difference to a plurality of starch filaments.

In one embodiment, the step of depositing the plurality of starch filaments on the molded member includes depositing the starch filament at an acute angle with respect to the filament receiving side of the molded member, wherein the acute angle is about 5 degrees. From about 85
Degrees.

[0018] In one embodiment, the molded member includes a resinous frame connected to the reinforcing element. The molded member is
It may be fluid permeable, fluid impermeable, or partially fluid permeable. The reinforcement element may be located between the filament receiving side and at least a portion of the back of the framework. The filament receiving side may include a substantially continuous pattern, a substantially semi-continuous pattern, a substantially non-continuous pattern, or any combination thereof. The framework includes a plurality of openings therethrough, which may be continuous, discrete, or semi-continuous, analogous and transposable to the framework pattern.

In one embodiment, the molded member comprises a first member.
It is formed from a reinforcement element disposed at the ridge and a resinous frame connected to the reinforcement element extending outwardly from the reinforcement element in a face-to-face relationship to form a second ridge. The shaped member may include a plurality of inter-woven yarns, felts, or any combination thereof.

When a plurality of starch filaments are deposited on the filament receiving side of the molded part, the filaments at least partially conform to the three-dimensional pattern of the molded part due to the application of their flexibility and / or hydraulic pressure differential. This forms a first region comprising a plurality of starch filaments supported by the patterned framework and a second region comprising a plurality of starch filaments deflected into the opening and supported by the reinforcing element.

In one embodiment, the shaped member includes a suspended portion. The resinous frame of this type of molded part includes a plurality of base portions extending outwardly from the reinforcement element and cantilevered wing portions extending laterally from the base portion with a second ridge. An air gap is formed between the cantilever wing and the reinforcing element, wherein the plurality of bases and the plurality of cantilever wings mutually form the three-dimensional filament receiving side of the molded member. This type of molding agent can be molded by joining at least two layers in a face-to-face relationship, with one frame portion of the layer corresponding to the opening of the other layer. The molded member including the suspended portion can also be formed by differentially cross-linking the photosensitive resin layer through a mask having a pattern including a differentially opaque area.

According to the present invention, the method of manufacturing the flexible structure may further include a step of compressing the plurality of starch filaments by applying, for example, mechanical pressure to selected portions of the plurality of starch filaments.

[0023] The method may further include a step of shortening the depth of the plurality of starch filaments. Depth shortening can be achieved by creping, microshrinking, or a combination thereof.

The electrospinning method of starch filaments has an extension viscosity of about 50 Pascal-second to about 20,000 Pascal-second.
Secondly, the starch composition is prepared; the starch composition is then electrospun to a size of about 0.001 dtex to about 13 dtex.
Making a 5 decitex starch filament; a process is included. The step of electrospinning the starch composition includes the step of electrospinning the starch composition through a die.

The starch in the starch composition has a weight average molecular weight of about 1,000 to about 2,000,000; and
The starch composition has a pore number of at least 0.05, more specifically at least 1.00. In one embodiment, the starch composition comprises from about 20% to about 99% by weight.
Amylopectin. The starch in the starch composition is
It has a weight average molecular weight of about 1,000 to about 2,000,000. The starch composition can contain a high polymer having a weight average molecular weight of at least 500,000.

The starch composition comprises from about 10% to about 8% by weight.
0% by weight starch, and about 20% to about 90% by weight
Can be contained. This type of starch has a temperature of about 20 ° C.
From about 100 Pascal second to about 15.0 at about 180 ° C
It may have an extensional viscosity of 00 Pascal-second.

[0027] The starch composition may comprise from about 20% to about 70% by weight of the starch and from about 30% to about 80% by weight of the additives. This type of starch composition contains about 200 Pascals.
Elongational viscosity of about 10,000 Pascal-seconds to about 10,000 seconds (about 20
From about 100 ° C to about 100 ° C).

Approximately 200 Pascal second to approximately 10,000
Starch compositions having an extensional viscosity of Pascal-seconds can have a pore number of about 3 to about 50. More specifically, about 30
Starch compositions having an extensional viscosity of 0 to about 5,000 Pascal-seconds can have a pore number of about 5 or about 30.

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

[0030] The starch composition may include an additive selected from the group consisting of a plasticizer and a diluent. Such starch compositions can further comprise from about 5% to about 95% by weight of protein, wherein the protein is corn-derived protein, soy-derived protein, wheat-derived protein, or any combination thereof. including.

The method for producing a starch filament can further include a step of elongating the starch filament with an air stream.

In one embodiment, providing a starch composition having an extensional viscosity of about 100 Pascal-seconds to about 10,000 Pascal-seconds during the process of making the flexible structure containing the starch filaments; Providing a filament receiving side and a back surface facing the filament receiving side, wherein the filament receiving side in this case is a substantially continuous pattern, a substantially semi-continuous pattern, an individual pattern, or an arbitrary combination thereof. Electrospinning the starch composition to produce a plurality of starch filaments; and depositing the plurality of starch filaments on the filament receiving side of the molded member, wherein Adapting the starch filament to the three-dimensional pattern on the filament receiving side. In an industrial method, the molding moves continuously in the longitudinal direction.

(Specific Description of the Invention) The following terms used in this specification have the following meanings. The term "flexible structure comprising starch filaments" or simply "flexible structure" is an assembly comprising a plurality of starch filaments, wherein the starch filaments are mechanically entangled with each other. To form a sheet-like product having certain predetermined microscopic, geometric, physical, and aesthetic properties.

The term "starch filament" is an article comprising an elongated, thin, highly flexible starch having an extremely long main axis as compared to two mutually perpendicular fiber axes perpendicular to the main axis. The aspect ratio of the principal axis length to the equivalent diameter of the fiber cross section perpendicular to the principal axis is more than 100/1, more specifically more than 500/1, even more specifically more than 1000/1, Specifically 5000 /
Exceeds one. The starch filament may contain other additives such as water, a plasticizer, and other optional additives.

The term "equivalent diameter" as used in the present invention is used to define the cross-sectional area and surface area of the starch fibers or filaments in the present invention, regardless of the shape of the cross-section. Therefore, the equivalent diameter is given by the equation S = 1
/ 4πD ² , where S is the cross-sectional area of the starch fiber or filament (regardless of geometry), π = 3.14159, D
Is an equivalent diameter). For example,
The cross-sectional area of the rectangle formed by the two facing sides “A” and the two facing sides “B” is represented by the formula S = A × B.
At the same time, this cross-sectional area can be expressed as a ring area having an equivalent diameter. Therefore, the equivalent diameter D is given by the equation S = 1
/ 4πD ² (where S is the known area of the rectangle) (of course, the equivalent diameter of the ring is the true diameter of the ring). The equivalent radius is one half of the equivalent diameter.

The term "pseudo-thermoplastic" in the context of "materials" or "compositions" refers to the use of these materials or compositions by the effects of high temperatures, dissolution in suitable solvents, or other techniques. In the case where the material and the composition can be softened to a blowing condition capable of forming and processing a starch filament suitable for forming a flexible structure, more specifically, when the material and the composition can be softened to a blowing condition that can be formed into a shape, Point. The pseudo-thermoplastic material can be molded, for example, under the influence of both heat and pressure. The difference between a quasi-thermoplastic material and a thermoplastic material is that the softening and liquefaction of the quasi-thermoplastic material is caused by the presence of a softening agent or a solvent. The point is that the material does not "melt" under these types of conditions and cannot reach the softening or flow conditions required for molding. The effect of moisture on the glass transition temperature and melting point of starch is measured by differential scanning calorimetry ("Cereal Chemistry" by Zeleznah and Hoseny et al., Vol 64,
No. 2, pages 121-124). A pseudo-thermoplastic melt is a pseudo-thermoplastic material in a fluid state.

The term "microscopic arrangement" and variations thereof refer to relatively small ("microscopic") details of a flexible structure, as opposed to its overall (or "macroscopic") arrangement. Regardless of the shape of the entire structure, it refers to details such as the surface texture of the flexible structure. "Microscopic" or "
The term "macroscopic" refers to the entire arrangement or a portion thereof when placed in a two-dimensional arrangement such as an XY plane.
For example, at a macroscopic level, this flexible structure when placed on a flat surface is a relatively thin, flat sheet. However, at a microscopic level, the structure includes a first plane having a first ridge. However, at a microscopic level, the structure comprises a plurality of first regions forming a first plane having a first ridge and a plurality of domes extending and extending outwardly through a framework region forming a second ridge. Or "
A pillow "section may be included.

"Strength" is a property that does not have a value that depends on a set of values within the plane of the flexure structure. A common intensity is an intensity that is retained by more than one region. In the present invention, such strengths of the flexible structure include density, base weight, bumps, opacity, and crepe frequency (if the structure is shortened in depth). Is not limited. For example, if the common indication of two different areas is a density value, the density value of one area can be different from the density value of another area. For example, areas such as the first and second areas are identifiable areas that can be distinguished from each other by individual intensities.

"Base weight" is the weight (in grams) of the unit surface of the starch flexure, the unit area being taken in the plane of the starch structure. The size and shape of the unit surface for measuring the base weight depends on the relative and absolute size and shape of the area having the partial base weight.

"Density" is the ratio of the base weight to the thickness of a region (perpendicular to the plane of the flexure). The apparent density is a value obtained by dividing the base weight of the sample by a caliper value incorporating an appropriate unit conversion table. The unit of the apparent density used in the present invention is g / cm ³ .

"Carryer" is the macroscopic thickness of a sample, measured as described below. The calipers should be clearly distinguished from the microscopic features of the area, the ridges of the differential area.

The "glass transition temperature" T _g is the temperature at which the viscous or rubbery state of a material changes to a relatively hard and brittle state.

"Vertical" (or MD) is the direction parallel to the flow of the flexible structure through the manufacturing equipment. "
Transverse direction (or CD) is the direction perpendicular to the machine direction and parallel to the general plane of the flexible structure being manufactured. "
X "," Y ", and" Z "refer to the conventional Cartesian coordinate system of Cartesian coordinates, where the mutually perpendicular coordinates"
X "and" Y "define the reference XY plane, and" Z "
-Define a right angle to the Y plane. "Z direction" is XY
In any direction perpendicular to the plane. Similarly, "Z dimension" means a dimension, distance or parameter measured in the Z direction. For example, if an element such as a molded member is curved or non-planar, the XY plane will follow the outline of the element.

"Substantially continuous" regions (areas / network /
A framework) refers to an area that can travel completely without interruption in the area through the line length and connect any two points. That is, a substantially continuous region has substantial "continuity" in all directions parallel to the first surface, and terminates only at the ends of the region. The term "substantially" in the context of continuity preferably refers to absolute continuity, but slight deviations from absolute continuity may be noticeable in the performance of the designed or intended structure (or molded part). This means that this is acceptable unless otherwise affected.

The term “substantially semi-continuous” region (area / network / frame) refers to an area that is parallel to the first plane and that exhibits “continuity” in all but one direction, except in at least one direction. In this area, a point that can connect any two points by a line that runs completely without being interrupted in the area through the line length. A semi-continuous framework may show continuity only in one direction parallel to the first plane. By analogy with the continuity region above, absolute continuity in all but one of the directions is preferred, but slight deviations from absolute continuity may result from the design or intended structure (or shaped member) This is acceptable as long as it does not significantly affect performance.

A "discontinuous" region refers to a discrete and discrete area that is discontinuous in all directions parallel to the first plane.

"Absorbency" is the ability to pick up and retain a fluid by various techniques including capillary, osmotic, solvent, or chemical action. Absorbency can be measured according to the test methods described herein.

"Flexibility" refers to the ability of a material or structure to deform without breaking under an applied load, regardless of the ability or inability of the material or structure to return to its pre-deformed shape. Point to.

The term "molded member" as used in the present invention can be used as a support on which a starch filament can be deposited during processing for producing a flexible structure, and the desired microscopic structure of the flexible structure according to the present invention. A structural element that can be used as a forming device to form (or "shape") graphics. The shaped member may comprise any element capable of imparting a three-dimensional pattern to the structure being formed, including but not limited to stationary plates, belts, woven fabrics, and bands.

"Reinforcing elements" are certain embodiments of a molded part that primarily function to provide or facilitate the integrity, stability, and durability of the molded part, including, for example, resinous materials. Although preferred elements, they are not necessarily limited thereto. The reinforcement element may be fluid permeable, fluid impermeable, or partially fluid permeable, and may comprise a plurality of woven yarns, felts, plastics, other suitable synthetic materials, or any combination thereof. Can include matching.

A "pressing surface" is a surface which can be compressed against the filament receiving side of a molded member having a plurality of starch filaments thereon, and which is provided with a starch filament in a molded member having a three-dimensional pattern of depressions / projections. A surface that is at least partially deflected.

"Decitex" or "dtex" is 1
Grams per 000 meter, Is a unit of measurement in the case of starch filaments expressed by

"Melt spinning" is a process in which a thermoplastic or pseudo-thermoplastic material is converted to a fibrous material by use of a thinning force. Melt spinning methods include mechanical drawing, melt blowing, spunbonding, and electrospinning methods.

The "mechanical stretching" method is a method in which a force is applied to a filament by bringing the filament into contact with a driving surface such as a roll for the purpose of applying a force to the filament to melt and fibrillate. .

"Molten blowing" is a process for producing a fibrous web or article directly from a polymer or resin using high velocity air or other suitable force for the purpose of thinning the filament. In the melt-blown method, a thinning force is applied in the form of high velocity air as the material exits the die or spinneret. The "spunbonding" process involves dropping a fiber at a predetermined distance under flow force and gravity, and then applying force using high velocity air or other suitable source.

The "electrospinning" method is a method of thinning fibers using voltage as a force.

The "dry spinning" process, also known as the "solution spinning" process, involves the use of a solvent drying step to stabilize fiber formation. Dissolve the material in a suitable solvent,
Methods of thinning utilizing mechanical stretching, solvent blowing, spunbonding, and / or electrospinning are included. The fibers stabilize as the solvent evaporates.

The "wet spinning" process involves dissolving a material in a suitable solvent and forming fibrils using mechanical stretching, solvent blowing, spanning bonding and / or electrospinning. You. As the fibers are formed,
The fibers are conveyed into a coagulation system consisting of a bath filled with a solution that solidifies the desired material to produce stable fibers. The term "substantially compatible with starch" high polymer refers to a substantially homogeneous mixture with starch (i.e., visually transparent) when the high polymer composition is heated above its softening and / or melting temperature. Or a composition that looks translucent) can be formed by the high polymer. "Melting temperature" means the temperature at or above which a starch composition can be melted or sufficiently softened and processed into a starch filament according to the present invention. Since certain starch compositions are pseudo-thermoplastic compositions, the composition in this case has a distinct "melting point"
Is not shown.

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

Flexible Structure Referring to FIGS. 1-3, a flexible structure 100 comprising a pseudo-thermoplastic starch filament includes at least a first region 110 and a second region 120. Each of the first region and the second region share at least one intensity, such as, for example, base weight or density. The intensity of the first region 110 is different in value from the intensity of the second region 120. For example, the density of the first region 110 is
May be higher than the density.

The first and second regions 110 and 120 of the flexible structure according to the present invention have different micro figures. For example, in FIG. 1, the first region 110 includes a substantially continuous network, and when the structure 100 is placed on a flat surface, the first ridge forms a substantially continuous network that forms the first surface. Including; the second region 120 may include a plurality of discrete areas dispersed through a substantially continuous network. In one embodiment, these discrete areas include discrete protrusions or "pillows" that extend outwardly from the network region and are more than the first ridge relative to the first plane. Form a large second ridge. The pillow may also include a substantially continuous pattern and a substantially semi-continuous pattern.

[0062] In one embodiment, the substantially continuous network has a relatively high density and the pillow may have a relatively low density. In other embodiments, the substantially continuous network region has a relatively small base weight, and the pillow may have a relatively large base weight. In other embodiments, the substantially continuous network region has a relatively low density,
And the pillow may have a relatively high density. Embodiments are also conceivable in which the substantially continuous network region has a relatively large base weight and the pillow has a relatively small base weight.

In another embodiment, the second region 120 includes a semi-continuous network. In FIG. 2, this second region includes an individual zone 122 similar to that of FIG. 1; and a semi-continuous zone 121, where 121 zone is the first of the structure 100 on the XY plane (ie, a flat surface). Extending in at least one direction, as seen in the surface formed by the region 110).

In the embodiment shown in FIG. 2, the flexible structure 1
00 is the intensity of the first region 110 and the second region 120
Includes the third region 130 having at least one intensity that is common and different in value. For example, the first
The area 110 has a common intensive property having a first value, the second area 120 has a common intensive property having a second value, and the third area 130 has a common intensive property having a third value. In this case, the first value is different from the second value and the third value
The value may be different from the second and first values.

At least three discriminatory regions 110, 12
If the structure 100 including 0, 130 is placed on a horizontal reference plane (e.g., XY plane) as described above, the first region 110 defines a plane having a first ridge, and the second region 110 12
0 extends to define a second ridge. An embodiment is also conceivable in which the third region 130 defines a third ridge, in which case at least one of the first, second and third ridges is different from at least one of the other ridges. For example, the third ridge may be intermediate between the first and second ridges.

The following table shows some possible combinations of embodiments of the structure 100 that include at least three regions with differential (ie, high, medium or low) intensities.
It is not limited to these. All of these embodiments are included within the scope of the present invention.

High strength High Medium Low Continuous Discontinuous Discontinuous Continuous Discontinuous --- Continuous --- Discontinuous Semi-continuous semi-continuous semi-continuous semi-continuous semi-continuous semi-continuous semi-continuous semi-continuous discontinuous semi-continuous semi-continuous discontinuous semi-continuous semi-continuous semi -continuous Discontinuous Continuous Discontinuous Discontinuous Continuous --- Discontinuous Semicontinuous Semicontinuous Discontinuous Semicontinuous Discontinuous Discontinuous Discontinuous Continuous Discontinuous Discontinuous Semicontinuous Discontinuous Discontinuous Discontinuous discontinuous---Continuous −−− continuous discontinuous −−− semicontinuous semicontinuous −−− discontinuous continuous

FIG. 3 shows yet another embodiment according to the present invention, wherein the second region 120 includes a plurality of starch pillows, at least some of which are starch dome portions 1.
28 and a starch cantilever wing 129 extending from the starch dome 128. Starch cantilever wing 129 is XY
From the surface, extending at an angle from the dome portion 128 and extending at an angle, a substantially void space or "pocket" 115 is defined between the first region 110 and the starch dome 128 and the starch cantilever wing 129 extending therefrom. Form.

The flexible structure 100, which is schematically illustrated in FIG. 3, is extremely absorbent for a given base weight, primarily due to the presence of substantially empty pockets 115 capable of receiving and holding large volumes of fluid. . Pocket 115 is characterized by having no or little starch filament therein.

Those skilled in the art will appreciate that the following methods for making flexible structures, as well as starch filaments and flexible structures 1
00 due to the overall high flexibility of the pocket 11
It will be appreciated that the presence of some amount of the individual starch filaments in 5 is acceptable as long as these filaments do not adversely affect the design and design of structure 100. In this context, the term “substantially” void pocket 115 refers to the neglected nature of the starch filaments or parts thereof due to the high flexibility of the structure 100 and the individual starch filaments containing the structure 100. It is intended to acknowledge that not some amount can be found in pocket 115. The density of the pockets 115 is 0.005 grams per cubic centimeter (g / cc) or less, more specifically 0.004 g / cc or less, and even more specifically 0.003 g / cc or less.

In another aspect, the flexible structure 100 including the cantilevered wing 129 is characterized by a further enhanced total surface area as compared to a control structure without the cantilevered wing 129. . The greater the number of individual cantilever portions 129 and their respective microscopic area, the greater the resulting microscopic specific surface area (i.e., the resulting microscope per unit of total macroscopic surface area of a structure placed on a flat surface). Those skilled in the art will appreciate that the specific surface area is even greater. One skilled in the art will also recognize that the greater the absorbent surface area of the structure, the greater its absorption capacity, provided that all other parameters are equal.

In an embodiment relating to the structure 100 including the cantilever wing 129, the cantilever wing 129 is
It is possible to include a third region of zero. For example, an embodiment in which the density of the starch cantilever wing portion 129 is intermediate between the density of the first region and the density of the second region including the dome portion is conceivable. In other embodiments, the density of the dome portion 128 may be relatively high in the first region 110 and the cantilever wing portion 12.
It can be in the middle of the relatively low density of nine. By analogy, the base weight of the cantilevered wing 129 may be equal to, in the middle of, or exceed the base weight of one or both of the first region 110 and the dome 128.

[0073] Preparation 8 and 9 of the flexible structure is a schematic representation of two embodiments of the process of the flexible structure 100 comprising starch filaments.

First, a plurality of starch filaments are prepared. The manufacture of the starch filament used in the flexible structure 100 of the present invention can be performed by various techniques known in the art. For example, starch filaments can be prepared from pseudo-thermoplastic molten starch compositions by various melt spinning methods.
The size of the starch filament may be from about 0.001 dtex to about 135 dtex, more specifically about 0.001 dtex.
It can range from 5 decitex to about 50 decitex, and even more specifically, from about 0.01 decitex to about 5.0 decitex.

No. 4,139,699 (Hernandez et al., 2)
No. 4,853,168 (Eden et al., August 1)
No. 4,234,480 (Hernandez et al., January, 1989)
Some of the references, including U.S. Pat. Nos. 5,516,815 and 5,316,57 (Buehler et al.), Relate to starch compositions for the manufacture of starch filaments employing a melt spinning process. The molten composition is extruded through a spinneret to produce a filament slightly larger in diameter than the orifice diameter (ie, swelling effect). This filament is then drawn down mechanically or thermomechanically with a drawing device.

Various techniques for making thermoplastic nonwoven structures from extruded polymers are known in the art and are useful for making long flexible starch filaments. For example, the extruded starch composition is pressed through a spinneret (not shown) to form a vertically oriented curtain of starch filaments that progress downward. The starch filament can be quenched with air using a suction-type drawing or shrinking air slot. U.S. Patent No. 5,292,239 (Zeldin et al., March 8, 19
No. 94) discloses an apparatus for reducing a remarkable vortex in air for the purpose of uniformly and consistently applying a drawing force to a starch filament. For the limited purpose of teaching methods and apparatus for reducing eddies in the airflow during starch filament formation,
The disclosure in this patent is incorporated into the description of the present invention by reference.

According to the invention, the starch filaments can be prepared from a mixture comprising starch, water, plasticizer and other additives. For example, a suitable starch mixture can be converted into a pseudo-thermoplastic melt by an extruder and then conveyed through a spinneret to a drawing device to convert into a vertically oriented curtain of downward-moving starch filaments. The spinneret may include an assembly known in the art. The spinneret assembly includes a plurality of nozzle holes with holes having a cross section suitable for producing starch filaments. If desired, the spinneret can be adapted to the fluidity of the starch composition such that the same flow rate is obtained in all nozzle holes. Alternatively, the flow rate may be changed using a differential nozzle.

The drawing device (not shown) located downstream of the extruder may include an open upper end, an opposing open lower end, and an air supply manifold for supplying compressed air to the downwardly directed internal nozzle. . As the compressed air passes through the internal nozzle, air is drawn into the open upper end of the extraction device, forming a downwardly directed, rapidly moving airflow. This air flow creates a withdrawal force on the starch filament, causing it to shrink or stretch prior to exiting the open low end of the withdrawal device.

It has now been found that starch filaments useful for the flexible structure 100 can be produced by an electrospinning process in which an electric field is applied to the starch solution to form a charged starch jet. Electrospinning is known in the art. "Electro-Spinning Process and Application of Electro-Spun Fiber
ss and Applications of Electro-Spun Fibers) ”(Doshi, Jayesh, Natwarlal, Ph.D., 1994)
Describes the electrospinning method and conducts studies of the forces involved in the method. This article also discloses some commercial applications of electrospun filaments. This article is incorporated by reference into the description of the present invention for the purpose of describing the principles of electrospinning.

US Pat. No. 1,975,504 (October 2, 1934
No. 2,123,992 (July 19, 1938); No. 2,1
No. 16,942 (May 10, 1938); No. 2,109,333 (2
No. 2,160,962 (June 6, 1939)
No. 2,187,306 (January 16, 1940); No. 2,1
No. 58,416 (May 16, 1939)
s) describes the electrospinning method and its equipment.

Other references describing the electrospinning method include: US Pat. No. 3,280,229 (Simons et al., Oct. 8).
No. 4,044,404 (Martin et al., August 30, 1966).
No. 4,069,026 (Simm et al., January 17, 1977).
No. 4,143,196 (Simm et al., March 6, 1979)
No. 4,223,101 (Fine et al., September 16, 1980); No. 4,230,650 (Guignard et al., October 28, 1980); No. 4,232,525 (Enjo et al., November 11, 1980);
No. 87,139 (Guignardo et al., Sep. 11, 1981);
No. 3,525 (Bornat et al., Apr. 6, 1982);
No. 07 (How et al., Nov. 12, 1985); No. 4,689,186 (Bornat et al., Aug. 25, 1987); No. 4,798,607 (M
iddleton et al., January 17, 1989; 4,904,272 (Mid
dleton et al., February 27, 1990); 4,968,238 (Sat)
terfield et al., November 6, 1990); No. 5,024,789 (B
arry et al., January 18, 1991); 6,106,913 (Scard)
No. 6,110,590 (Za)
rkoob et al., August 29, 2000). These disclosures are incorporated herein by reference for purposes of describing the general principles of electrospinning and related equipment.

Although the above references teach various electrospinning methods and apparatus, the starch composition may be a flexible structure 1 according to the present invention.
It does not teach that it can be successfully processed and extruded into a thin, substantially continuous, starch filament suitable for the formation of C.00. Since natural starch generally has a granular structure, it cannot be processed by electrospinning. It has now been found that modified "structurally disrupted" starch compositions can be successfully processed and processed by using electrospinning.

"Meltable starch compositions" [(Larry
Neil Mackey et al., Attorney Docket Number # 7967R)]
Same assignee patent application (date of filing of this application)
Discloses a starch composition suitable for producing a starch filament used in the flexible structure 100 of the present invention.
The starch composition disclosed herein has a weight average molecular weight of about 1,0.
A high polymer comprising from 00 to about 2,000,000 starch and substantially compatible with the starch and having a weight average molecular weight of at least 500,000. In one embodiment, the disclosed starch composition can comprise from about 20% to about 99% by weight amylopectin. The disclosure of the patent application to the same assignee is incorporated herein by reference.

According to the present invention, a starch polymer is mixed with water, a plasticizer and other additives, and the resulting melt is extruded, for example, to produce a starch filament suitable for the flexible structure of the present invention. It is designed to be able to do. The starch content of this starch filament ranges from traces to 100% by weight, or starch and other preferred materials such as cellulose,
It may be a synthetic material, a protein, or a blend thereof with a combination thereof.

[0085] Examples of starch polymers include any native starch, physically modified starch or chemically modified starch. Among the natural suitable starches are wheat starch, potato starch, sweet potato starch, wheat starch, sago coconut starch, tapioca starch, rice starch, soybean starch, arrowroot starch, amioca starch, bracken starch, lotos starch, wax. Includes, but is not limited to, high quality corn starch, high amylose wheat starch, and commercially available amylose powder. Natural starch, especially wheat starch and wheat starch are suitable starch-based polymers because they are inexpensive and have a stable supply.

A physically modified starch can be formed by changing the dimensions of its structure. Examples of physically modified starch include α
-Starch, fractionated starch, wet and heat treated starch and mechanically treated starch.

The chemically modified starch can be formed by reacting the OH group of the starch with an alkylene group and another ether, ester, urethane, carbamate, or isocyanate group-forming substance. Hydroxyalkyl, acetyl, or carbamate starch or mixtures thereof are useful chemically modified starches. The degree of substitution of the chemically modified starch is 0.05 to 3.0, preferably 0.05 to 0.2.

The natural water content of the starch is about 5% of the starch
To 16% by weight. Water content about 8% to 12% by weight
Is the most common. In one embodiment of the present invention, the amylose content of the starch is usually from 0% to about 80% by weight, more usually from about 20% to about 30% by weight (based on starch).

[0089] Plasticizers can be added to the starch polymer to reduce the glass transition temperature of the starch filaments to be made and increase the flexibility of the filaments. In addition, the presence of the plasticizer reduces the melt viscosity, which in turn facilitates melt extrusion. The plasticizer is an organic compound having at least one hydroxyl group, such as a polyol. Sorbitol, mannitol, D-glucose, polyvinyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, sucrose, fructose, glycerol and combinations thereof have proven to be suitable. Examples of plasticizers include about 0.1% to about 70% by weight, more specifically about 0.2% to about 30% by weight,
Even more specifically, sorbitol, sucrose, fructose in an amount of about 0.5% to about 10% by weight is included.

Other additives are usually added to the starch polymers as processing aids and for modifying the properties of the extruded starch filaments, such as elasticity, dry tensile strength, wet strength, and the like. The usual content of the additive is in the range of 0.1% by weight to 70% by weight on a non-volatile basis (the amount added is calculated by excluding volatile components such as water). Examples of additives include urea, urea derivatives, crosslinkers, emulsifiers, surfactants, lubricants, proteins and their alkali metal salts, biodegradable synthetic polymers, waxes, low-melting synthetic thermoplastic polymers, binder resins, stretch resins Agents, and mixtures thereof, but are not limited thereto. Examples of biodegradable synthetic polymers include, but are not limited to, polycaprolactone, polyhydroxybutyrate, polyhydroxyvalerate, polylactide, and mixtures thereof. Examples of other additives include optical brighteners, antioxidants, flame retardants, dyes, pigments, and fillers. In the present invention, the additive containing urea is
Advantageously, from 0.5% to 60% by weight is added to the starch composition.

Examples of spreading agents suitable for use in the present invention include gelatin; wheat protein, sunflower protein,
Plant proteins such as soy protein and cottonseed protein;
Alginate, carrageenan, guar gum, agar, gum arabic, other gums, and water-soluble polysaccharides such as pectin; and water-soluble cellulose derivatives such as alkyl cellulose, hydroxyalkyl cellulose, carboxymethyl cellulose and the like are included. Also, polyacrylic acid,
Water-soluble synthetic polymers such as polyacrylate, polyvinyl acetate, polyvinyl alcohol, and polyvinylpyrrolidone can also be used.

In order to improve the flow characteristics of the starch material during processing in the present invention, a lubricant compound may be further added. Examples of lubricating compounds preferably include animal and vegetable fats and oils, especially hydrogenated fats and oils, especially room temperature solid fats and oils. Examples of other lubricant materials include monoglycerides,
Diglycerides and phosphatides, especially lectins, are included. Preferred lubricant compounds for the present invention include monoglycerides, glycerol monostearate.

As an inexpensive filler or processing aid, further additives selected from inorganic particles such as oxides of magnesium, aluminum, silicon and titanium can be added. In addition, alkali metal salts, alkaline earth metal salts,
Additives such as inorganic salts including phosphates can also be used as processing aids.

Other additives may be used depending on the particular use of the end product under consideration. For example, in products such as toilet paper, disposable towels, decorative paper and other similar products,
Wet strength is a desirable attribute. It is therefore often desirable to add a starch polymer crosslinker known as a "wet strength" resin.

A general discussion of the types of wet strength resins used in paper products can be found in the TAPPI Monograph Series N
o.29, "Wet strength on paper and paperboard" (Wet Streng
thin Paper and Paperboard), Technical Associati
on of the Pulp and Paper Industry (New York, 1965
)) Has disclosure. The most useful wet strength resins generally exhibit cationic properties. The polyamide-epichlorohydrin resin is a cationic polyamidoamine-epichlorohydrin-based wet-strength resin, and has been found to be particularly useful. Examples of useful resins of this type are described in U.S. Pat.
No. 3,700,623 (to Keim, Oct. 24, 1972) and No. 3,772,076 (to Keim, Nov. 13)
Dated, 1973), which is hereby incorporated by reference. One publisher of useful polyamide-epichlorohydrin resins is Hercules, Inc. of Wilmington, Delawa
The resin is marketed under the trade name "Kymene ^tM ".

Glyoxylated polyacrylamide resins have also been found to be useful as wet strength resins. These resins are disclosed in U.S. Pat. No. 3,556,932 (Coscia et al., January 19
No. 3,556,933 (Williams, dated 1971).
(January 19, 1971), which is hereby incorporated by reference. One publisher of glyoxylated polyacrylamide resins is Cytec Co. of Stanford, Connecticu
This resin is marketed here under the trade name “Parez ^™ 631 NC”.

[0097] Other water-soluble cationic resins useful in the present invention are urea formaldehyde resins and melamine formaldehyde resins. The most common functional groups on these polyfunctional resins are amino groups and nitrogen-containing groups such as methylol groups bonded to nitrogen. Polyethyleneimine-type resins have also been found to be useful in the present invention. In addition, Caldas ^R 10 (manufactured by Japan Carlit) and CoBond ^R 1000 (National Starch and Chemical
Company) (temporary wet strength resin) can also be used in the present invention.

One of the cross-linking agents used in the present invention is a wet-strength resin “Kymene ^™ ”, which is used in an amount of about 0.
It ranges from 1% to about 10% by weight, more specifically from about 0.1% to about 3% by weight.

To make a starch filament useful for the flexible structure 100 according to the present invention, the starch composition must have a range of viscoelastic properties, such as a range of extensional viscosities and a range of pore numbers. It needs to behave. Of course, depending on the type of processing method (eg, melt blowing, electrospinning, etc.), the required viscoelastic properties of the starch composition can be indicated.

The extensional viscosity or elongational viscosity (η _e ) relates to the melt extensibility of a starch composition, and is particularly important in an extension processing method such as starch filament production. Depending on the type of deformation of the composition, the extensional viscosities include three types: uniaxial or single extensional viscosities, biaxial extensional viscosities, and pure shear extensional viscosities. Uniaxial elongational viscosity is important for uniaxial elongation processes such as mechanical elongation, melt blowing, spunbonding, and electrospinning. The extension viscosities of the other two types are
It is important in the case of biaxial stretching or biaxial forming when producing films, filaments, foams and sheets and parts.

In the case of conventional thermoplastic resins for fiber spinning, such as polyolefins, polyamides and polyesters, there is a high correlation between the extensional viscosities and the shear viscosities of these conventional thermoplastics and their blends. That is,
Spinnability is a property primarily controlled by melt extensional viscosity, but spinnability of these materials can be determined simply by melt shear viscosity. This correlation is very strong and the textile industry depends on its melt shear viscosity for its choice and formulation of melt spun materials. This melt extensional viscosity is rarely used as an industrial screening tool.

It is therefore unexpected to find that the starch compositions of the present invention do not necessarily show this type of correlation between shear viscosity and extensional viscosity. Since the starch compositions of the present invention exhibit melt flow behavior typical of non-Newtonian fluids, the strain hardening behavior, or elongational viscosity, of the compositions increases as strain or deformation increases.

For example, when a high polymer selected according to the present invention is added to a starch composition, the shear viscosity of the composition remains relatively unchanged or even slightly decreases. In accordance with conventional beliefs, this type of starch composition should exhibit reduced melt processability and should therefore not be suitable for melt extension. However, unexpectedly, it has been found that the starch composition of the present invention significantly increases the extensional viscosity even when a small amount of a high polymer is added. As a result, the starch compositions of the present invention have enhanced melt extensibility and are therefore suitable for melt stretching processes, especially those including blow molding, spunbonding and electrospinning.

The shear viscosity measured according to the test method described below is less than about 30 Pascal-seconds (Pa · s), more specifically from about 0.1 to less than about 10 Pascal-seconds, and even more specifically. Starch compositions of from about 1 to less than about 8 Pascal-seconds are useful for melt-refining in the present invention. Certain starch compositions exhibit low melt viscosities so that they can be mixed, transported or processed in conventional polymer processing equipment for viscous fluids, such as fixed mixers with metering pumps and spinnerets.
The shear viscosity of the starch composition can be effectively modified by the molecular weight and molecular weight distribution of the starch, the molecular weight of the high polymer, and the amount of plasticizer and / or solvent used. It is believed that reducing the average molecular weight of the starch is an effective means for reducing the shear viscosity of the composition.

In one embodiment according to the present invention, the extensional viscosity range of the melt-processable starch composition of the present invention is from about 50 Pascal-second to about 20,000 Pascal-second at the die temperature.
Seconds, typically from about 100 Pascal-seconds to about 15,000
0 Pascal-second, more typically from about 200 Pascal-second to about 10,000 Pascal-second, even more typically from about 300 Pascal-second to about 5,000 Pascal-second.
Seconds, most typically from about 500 Pascal seconds to about 3,5
00 Pascal second. This extensional viscosity is calculated according to the analytical method described below.

A number of factors influence the rheological behavior of the starch composition, including the extensional viscosity, including, among these factors, the amount and type of polymeric components used, and the components including starch and high polymers. Molecular weight and molecular weight distribution, amylose content of starch, amount and type of additives (eg, plasticizers, diluents, processing aids), processing conditions such as temperature, pressure and deformation rate, relative humidity, non-Newtonian The case includes the deformation history (ie, time or strain history dependency). Certain materials are capable of strain-hardening, i.e., the elongational viscosity of the material increases with increasing strain. This phenomenon is believed to be due to the stretching of the entangled polymer network. Removing the strain from the material causes the stretched entangled polymer network to relax and reduce the strain level, depending on the relaxation time constant. This constant is a function of temperature, polymer molecular weight, solvent or plasticizer concentration, and other factors.

The presence and nature of the high polymer has a significant effect on the melt extensional viscosity of the starch composition. High polymers useful for enhancing the melt extensibility of the starch compositions in the present invention are typically high molecular weight, substantially linear polymers. Moreover, high polymers that are substantially compatible with starch are most effective at enhancing the extensibility of the starch composition.

It has been found that starch compositions useful for melt-stretching typically have at least a 10-fold increase in extensional viscosity when the selected high polymer is added to the composition. The starch composition in the present invention is typically about 10 to about 500 times, more typically about 20 to about 300 times, and most typically about 30 to about 10 times, with the addition of the selected high polymer.
It shows that the extensional viscosity increases by 0 times. The higher the high polymer concentration, the greater the increase in extensional viscosity. High polymer, Henc
ky Elongation viscosity at strain 6 is 200 to 2000P
It can be added to adjust to a second. For example, polyacrylamide having a molecular weight of 1 (million) to 15 (million) can be added in an amount of 0.001% to 0.1% for the composition of the starch.

The type and concentration of the starch used also affects the extensional viscosity of the starch composition. Generally, as the amylose content decreases, the extensional viscosity increases. In general, as the starch molecular weight increases within the prescribed range, the extensional viscosity increases. Finally, generally, the higher the starch concentration in the composition, the higher the extensional viscosity (conversely, the higher the additive concentration in the composition, the lower the extensional viscosity).

The temperature of the starch composition has a significant effect on the extensional viscosity of the starch composition. For the purposes of the present invention, for controlling the temperature of the starch composition, if suitable for the particular method employed,
Any conventional approach can be used. In embodiments where the starch filaments are made through the die, the die temperature significantly affects the extensional viscosity of the extruded starch composition.
Generally, as the temperature of the starch composition increases, the extensional viscosity of the starch composition decreases. The temperature of the starch composition is from about 20 ° C to about 180 ° C, more specifically from about 20 ° C to about 90 ° C,
More specifically, from about 50 ° C to about 80 ° C. It should be understood that the presence or absence of solids in the starch composition affects the required temperature.

To express the extensional flow behavior, the Trouton ratio (T
r) is often used. This trouton ratio is defined as the ratio between the extensional viscosity (η _e ) and the shear viscosity (η _s ):

(Equation 1) Where the extensional viscosity η _e is the deformation rate (ε ^● ) and time (t)
Depends on. For a Newtonian fluid, the uniaxial extension Trouton ratio is a constant 3. For non-Newtonian fluids, such as the starch composition in the present invention, the extensional viscosity depends on the deformation rate (ε ^● ) and time (t). It has been found that the melt processing composition according to the invention has a trouton ratio of at least 3. A typical Trouton ratio measured at processing temperature and an elongation rate of 700 s ^-1 at Hencky strain 6 is about 10
To 5000, more typically about 20 to 1000, even more typically about 30 to 500.

The applicant has also found that the number of pores (Ca) of the starch composition as it passes through the die is important for melt processability. The number of pores (Ca) is a dimensionless number represented by the ratio of viscous fluid force to surface tension. If this viscous force is not significantly greater than the surface tension near the exit of the pore die, the fluid filaments break into droplets, a phenomenon commonly referred to as a spray phenomenon. The number of pores is calculated according to the following equation: Ca = (η _s · Q) / (π · r ² · σ) where η _s is the shear viscosity (Pascal · _m ) measured at a shear rate of 3000 s ^−1. ), Q is the volume unit flow rate (m ³ / sec) flowing through the pore die, and r is the pore die radius (m) (for non-annular orifices, equivalent diameter / radius can be used). , Σ is the surface tension of the fluid (Newton / m).

As noted above, the number of pores is related to the shear viscosity, and is thus affected by the same factors and in the same manner as affecting the shear viscosity (described above). The term "inherent" as used herein in connection with pore number or surface tension refers to the property of a starch composition that is not affected by external factors, such as, for example, the presence of an electric field. The term "effective" refers to the property of the starch composition being affected by extraneous factors, such as the presence of an electric field.

In one embodiment of the present invention, the melt processable starch composition has at least 0.01 intrinsic pores and at least 1.0 effective pores upon passing through the die. Without static electricity, the number of pores needs to be more than 1 for stabilization, and more than 5 is preferable for improving the stability of the filament. When static electricity is used, the charge repulsion counters the surface tension effect so that the number of intrinsic pores measured without charge can be less than one. When a voltage is applied to the filament, the effective surface tension decreases and the effective pore number increases according to the formula:

Although the number of pores is expressed in various forms, a typical equation that can be used to determine the intrinsic pore number of a material is as follows: Ca _inherent = η _S · ν / σ where , Ca _inherent is the intrinsic pore number, η _S is the shear viscosity of the fluid, ν is the linear velocity of the fluid, and σ is the surface tension.

A representative sample in the present invention has the following composition and properties: "Purity Gum 59" manufactured by National Starch Inc. 40.00% Deionized water 59.99% "Superfloc N-3000 LMW" manufactured by Cytec (high Molecular weight polyacrylamide) 0.01% Test temperature 120 ° F Shear viscosity (3000S ^-1 ) 0.1 Pa · s Nozzle diameter. 0254 cm linear velocity. 236m / sec Intrinsic surface tension 72 dynes / cm

If no electrostatic charge is imparted to the fluid, this material will experimentally flow through the top of the nozzle to form small droplets,
Next, it falls under gravity as individual droplets. As the voltage applied to the system increases, the size of the droplet becomes smaller and begins to accelerate towards the drop mechanism. When the voltage reaches a limit (25 kilovolts for this sample), no more droplets form at the top of the nozzle and small continuous fibers are ejected from the top of the nozzle. Thus, the applied voltage overcomes the surface tension and eliminates the pore breaking mode. The effective pore number is thus a number greater than one. Laboratory tests under the above solution and experimental conditions resulted in substantially continuous fibers. The fibers were collected on a vacuum screen in fiber mat form. Analysis using light microscopy showed that the resulting fibers were continuous and 3-5 microns in diameter.

In certain embodiments, the number of unique pores is at least 1, more specifically from 1 to 100, even more specifically from about 3 to about 50, and most specifically from about 5 to about 30.
It is.

The starch compositions of the present invention are processed in a fluidized state, which typically occurs at a temperature at least equal to or above the "melting temperature". Thus, the processing temperature range is controlled by the "melting temperature" of the starch composition, which is measured according to the test methods described in detail below. The melting temperature of the starch composition is from about 20 to about 180 ° C, more specifically from about 30 to about 1
30 ° C, more specifically in the range of about 50 to about 90 ° C. The melting temperature of the starch composition is a function of the amylose content of the starch (higher amylose content requires higher melting temperatures), water content, and type of plasticizer.

Examples of uniaxial stretching methods for starch compositions include melt spinning, melt blowing, and spunbonding. These methods are described in detail in the following U.S. Patents, the disclosures of which are incorporated herein by reference: U.S. Patent No. 4.064,605 (Akiyama et al., December 27, 1977).
No. 4,418,026 (Blackie et al., November 29, 1983)
No. 4,855,179 (Bourland et al., August 8, 1989)
No. 4,909,976 (Cuculo et al., March 20, 1990)
No. 5,145,631 (Jezic et al., September 8, 1992)
No. 5,516,815 (Buehler et al., May 14, 1996)
No. 5,342,335 (Rhim et al., August 30, 1994)
Attached).

The schematic diagram shown in FIGS. 7, 8 and 9 is an apparatus 10 for making a starch composition useful in the flexible structure of the present invention. Apparatus 10 can include, for example, a single or twin screw extruder, a positive displacement pump, or a known combination thereof. The total water content of the starch solution, ie, the amount of natural water plus the amount of added water, is from about 5% to about 80% by weight, more specifically from about 10% to about 60% by weight (based on the total weight of the starch material). is there. The starch material is heated to a high enough temperature to form a pseudo-thermoplastic melt. Such temperatures usually exceed the glass transition temperature or / and melting temperature of the material to be formed. The pseudo-thermoplastic melt in the present invention is a polymer fluid having a shear rate dependent viscosity known in the art. This viscosity increases with increasing shear rate as well as with increasing temperature.

The starch material can be heated in a closed volume in the presence of a low concentration of water to convert the starch material into a pseudo-thermoplastic melt. This closed volume may be a closed container or may be a volume created by the sealing action of the feed, such as occurs in an extruder screw. The pressure created in the closed volume includes the pressure due to the vapor pressure of water as well as the pressure due to the compressed material in the extruder screw barrel.

A chain scission catalyst that cuts the glycosidic bonds of the starch macromolecules to reduce the starch molecular weight can be used to reduce the viscosity of the pseudo-thermoplastic melt. Examples of useful catalysts include:
Inorganic acids and organic acids are included. Examples of useful inorganic acids include hydrochloric, sulfuric, nitric, phosphoric and boric acids and partial salts of polybasic acids such as NaHSO ₄ or NaH
₂ PO _{4 and the} like are included. Examples of useful organic acids include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid,
Included are oxalic acid, citric acid, tartaric acid, itaconic acid, succinic acid, and other organic acids including polybasic acid partial salts known in the art.

The molecular weight reduction of the unmodified starch used can be reduced by a factor of 2 to 5000, more specifically by a factor of 1 to 4000. The catalyst concentration is from 10 ^-6 to 10 ^-2 mole, and more specifically from 0.1 x 10 ^-3 to 5 x 10 ^-3 mole, per mole of anhydrous glucose units of the starch.

In FIG. 7, a starch composition is supplied into an electrospinning apparatus 10 to make a starch filament for making a flexible structure 100 according to the present invention. The apparatus 10 includes a housing 11 configured and arranged to receive a starch composition 17 (arrow A), wherein the starch composition is
After being held inside, it is extruded into the starch filament 17a through the jet 14 of the die head 13 (arrow D). A tubular cavity 12 is provided for circulating a heating fluid for heating the starch composition to a desired temperature (arrows B and C). For heating the starch composition, other known heating means used for electric heating, pulse combustion, water and steam heating, and the like can be used.

The electric field is applied directly to the starch solution, for example via a charged probe, or to the housing 11 and / or the extrusion die 13. If desired, the molded member 200 may be electrically charged with a charge opposite to that of the extruded starch filament. Alternatively, the molding may be placed on the ground. The potential difference ranges from 5 kV to 60 kV, more specifically from 20 kV to 40 kV.

Next, the plurality of extruded starch filaments are deposited on the molding member 200 which moves in the longitudinal direction MD at a fixed distance from the apparatus 10. This distance must be sufficient to allow the starch filament to stretch and then dry while at the same time maintaining a charge differential between the starch filament exiting jet nozzle 14 and the molding member 200. To this end, a stream of dry air may be contacted with the plurality of starch filaments to rotate the plurality of starch filaments at an angle. In this way, it is possible to maintain the minimum distance between the jet nozzle 14 and the molding member 200 for the purpose of maintaining the charge difference between the jet nozzle 14 and the molding member 200, and at the same time to efficiently dry the filament. In addition, the length of the filament between the nozzle and the molding member 200 can be minimized. In this type of arrangement,
The molding member 200 may be disposed at a fixed angle with respect to the direction of the fiber filament exiting the jet nozzle 14 (arrow D in FIG. 7).

Optionally, the attenuating air may be used in conjunction with an electrostatic force to provide a stretching force such that the starch filaments are attenuated or stretched prior to being deposited on the molded member 200. FIG. 7A shows an example of an embodiment of a die head with a tubular orifice 15 surrounding the jet nozzle 14 and three other orifices 16 equally spaced at 120 ^° around the jet nozzle 14 for attenuating air. FIG. Of course, the present invention contemplates other known arrangements for the attenuating air.

According to the present invention, the size of the starch filament may be from about 0.01 dtex to about 135 dtex, more specifically from about 0.02 dtex to about 30 dtex.
Decitex, even more specifically in the range of about 0.02 decitex to about 5 decitex. The cross-sectional shapes of starch filaments are annular, oval, square, triangular,
It can be of various shapes such as, but not limited to, hexagonal, cross, star, irregular, and any combination thereof. It should be understood by those skilled in the art that these various shapes may be formed due to the difference in the shape of the die nozzle for starch filament production.

FIG. 10A is a schematic diagram showing some possible, but not limiting, cross-sections of starch filaments. The cross-sectional area of the starch filament is the area perpendicular to the main axis of the starch filament and outlined by the boundary formed by the outer surface of the starch filament in one plane of the cross section. It is believed that the greater the surface area of the starch filament (per unit length or weight of the filament), the more opaque the flexible structure containing the starch filament. Accordingly, increasing the equivalent diameter of the starch filament to maximize the surface area of the starch filament has the advantage of increasing the opacity of the flexible structure 100 in the present invention. One way to increase the equivalent diameter of the starch filament is to form a starch filament having a non-annular, multifaceted cross-sectional shape.

Moreover, the starch filament need not have a uniform thickness and / or cross-section throughout the length or part of the filament. For example, FIG. 10 is a schematic diagram showing the fraction of starch filaments having different cross-sections along the length. Such different cross sections can be formed, for example, by changing the internal pressure of the die, or by changing at least one of the properties of the atomized or dry air of the melt-blowing method, or by a combination of melt-blowing and electrospinning. .

Some starch filaments have "notches" distributed at intervals along the length or part of the filament. This type of variation of the starch filament cross-sectional area along the length of the filament increases the flexibility of the filament and facilitates the ability of the filaments to be entangled in the structure 100, thereby increasing the flexibility and flexibility of the structure 100. It is thought to have a beneficial effect on The above notches or other beneficial irregularities in the starch filament may be formed by contacting the starch filament with a surface having sharp angles or protrusions as described below.

The next step of the method includes a step of preparing the molded member 200. Forming member 200 includes a patterned cylinder (not shown) or other patterning member, such as a belt or band. This molded member 20
0 comprises a filament contact side 201 and a back face 202 facing the filament contact side 201. Fluid pressure differences (e.g., due to reduced pressure under the belt or in the drum) force the starch filaments into the pattern of the molding to form prominent regions within the flexible structure.

In the process of manufacturing the structure 100 according to the invention, a starch filament is deposited on the filament contact side 201. Typically, the second side 202 contacts devices such as support rollers, guide rollers, pressure reducing devices, etc., depending on the needs of the particular method. The filament contact side 201 includes a three-dimensional pattern including a protrusion and / or a recess. Usually (but not necessarily), the pattern is a non-random repeating pattern. The three-dimensional pattern on the filament contact side 201 may be a substantially continuous pattern (FIG. 4), a substantially semi-continuous pattern (FIG. 5), a pattern having a plurality of individual protrusions (FIG. 5), or any of these. May be included. When a plurality of starch filaments are deposited on the filament contacting side 201 of the molded member 200, the group of flexible starch filaments at least partially conform to the molding pattern of the molded member 200.

The molded member 200 includes a belt or band that is macroscopically single plane when placed on the reference plane XY, in which case the Z direction is perpendicular to the XY plane. Similarly, the flexible structure 100 is macroscopically single-plane, XY
It is considered to be located in a plane parallel to the plane. The caliper or thickness of the flexible structure 100 extends along the Z direction perpendicular to the XY plane, or the ridges of the shaped member 200 or the differential areas of the flexible structure 100 extend.

If desired, the formed member 200 including the belt can be implemented as a pressure belt. Pressed felts suitable for use in the present invention can be made according to the teachings of the following references: US Pat. No. 5,549,790 (Phan, Aug. 27, 1996);
No. 5,556,509 (Trokhan et al., September 17, 1996);
No. 5,629,052 (Trokhan et al., May 13, 1997); No. 5,637,194 (Ampulski et al., June 10, 1997);
No. 5,674,663 (McFarland et al., Oct. 7, 1997);
No. 5,693,187 (Ampulski et al., December 2, 1997);
No. 5,709,775 (Trokhan et al., January 20, 1998);
No. 776,307 (Ampilski et al., July 7, 1998);
No. 95,440 (Ampulski et al., Aug. 18, 1998); No. 5,81
No. 4,190 (Phan, September 29, 1998); No. 5,817,377 (Trokhan et al., October 6, 1998); No. 5,846,379 (Ampulski et al., December 8, 1998); 5,855,739
No. 5,861,082 (Ampulski et al., January 19, 1999). These disclosures are incorporated by reference into the description of the present invention. In another embodiment, the molded member 200 can be implemented as a press felt in accordance with the teachings of US Pat. No. 5,569,358 (Cameron, Oct. 29, 1996).

[0137] One main embodiment of the molded member 200 includes:
A resin frame 210 connected to the reinforcement element 250 is included. The resin frame 210 has a certain preselected pattern. For example, FIG. 4 shows a substantially continuous framework 210 having a plurality of openings. The reinforcement element 250 in some embodiments is substantially fluid permeable.
Fluid permeable reinforcement element 250 includes a woven screen, or aperture element, felt, or any combination thereof. Reinforcing element 25 indicated by opening 220 in the molded part
The zero portion prevents the starch filament from passing through the molded member, thereby reducing the occurrence of pinholes in the flexible structure 100. If the use of a woven screen for the reinforcement element 250 is not desired, a net, pressure felt or plate or a film with multiple holes can provide adequate support and strength for the framework 210. A preferred reinforcing element 250 is disclosed in U.S. Patent No. 5,496,62.
Issue 4 (Stelljes et al., May 5, 1996); 5,500,277
No. 5,566,724 (Trokhan et al., Oct. 22, 1996), the disclosures of which are incorporated herein by reference.

Various types of fluid permeable enhancing elements 250
For example, they are described in U.S. Patent Nos. 5,275,700 and 5,954,097, the disclosures of which are incorporated herein by reference. The reinforcing element 250 includes a felt called "press felt" used in conventional papermaking. Framework 2
10 is applicable to reinforcement element 250 as taught by the following U.S. Patent Publication: U.S. Pat. No. 5,549,790 (Phan, Aug. 27, 1996);
No. 5,556,509 (Trokhan et al., On September 17, 1996); No. 5,580,423 (Ampulski et al., On December 3, 1996); No. 5,609,725 (Phan, on March 11, 1997); 5th, 62nd
9,052 (Trokhan et al., March 13, 1997); 5,637,
No. 194 (Ampulski et al., June 10, 1997); No. 5,674,6
No. 63 (McFarland et al., Oct. 7, 1997); 5,693,1
No. 87 (Ampulski et al., December 2, 1997); 5,709,77
No. 5 (Trokhan et al., On January 20, 1998); No. 5,795,440 (Ampilski et al., On August 18, 1998); No. 5,814,190 (Phan, on September 29, 1998); 5,817,377 (Trokha
No. 5,846,379 (Ampilski)
Et al., December 8, 1998). These disclosures are incorporated herein by reference.

[0139] Alternatively, the reinforcement element 250 may be fluid impermeable. The fluid impervious reinforcing element 250 may be the same or different polymer resin-based material from the material used to fabricate the framework 210 of the molded member 200 of the present invention; a plastic material; a metal; any other suitable natural or Synthetic materials; or any combination of these materials. It will be appreciated by those skilled in the art that the fluid impermeable reinforcement element 250 could also make the molded member 10 generally fluid impermeable. Reinforcement element 2
50 may be partially fluid permeable and partially fluid impermeable. That is, some portions of the reinforcement element 250 may be fluid permeable and other portions may be fluid impermeable. The molded member 200 may be entirely fluid permeable, fluid impermeable, or partially fluid permeable. In the partially fluid-permeable molded member 200, only a part or a plurality of macroscopic sections or a plurality of sections of the molded member 200 are fluid-permeable.

[0140] If desired, a reinforcement element 250 including a Jacquard-type tissue can be utilized. U.S. Pat. No. 5,429,686 (Chiu et al., Jul. 4/95); 5,672,248 (Wendt)
No. 5,746,887 (Wendt et al., 5/5 /).
No. 6,017,417 (Wendt et al., 1/25/00), there is an explanatory diagram of a belt having a jacquard organization, and these disclosures are used for limiting purposes showing the basic configuration of the jacquard organization. Join here as a reference for The present invention contemplates a molded member 200 that includes a filament contact side 201 having a Jacquard texture. This kind of Jacquard texture can be used as the forming member 500, the forming member 200, the pressing surface, and the like. Jacquard texture is particularly useful when compression or imprinting of the nip structure is not desired, as would normally occur when transported to a Yankee type drying drum.

According to the present invention, one of the molded members 200,
Some or all are disclosed in US Pat. No. 5,972,813 (P.
It may be "blind" or "closed," as described in olat et al., Oct. 26, 1999, incorporated herein by reference. As described in this patent, it is used to make the rubber and silicone openings 220 fluid impermeable.

The embodiment of the molded member 200 of FIG. 6 includes a plurality of suspensions 219 extending from the plurality of bases 211 (usually in a lateral direction). This suspension 219 rises from the reinforcing element 250 to form a void space 215 into which the starch filament according to the invention is deflected, FIG.
Forming a cantilevered wing portion 129, as described above. Molded member 200 including suspension 219 may include a multilayer structure formed by at least two layers (211, 212) connected together in a face-to-face relationship (FIG. 6). Each of these layers includes a structure similar to one of the above referenced patents. Layer (2
11, 212) may have at least one opening (220, FIGS. 4, 4A) extending between the top and bottom surfaces. The connected layers are such that at least one opening of one layer forms a layer with a part of the framework of the other layer and a part of the framework of the other layer (in a direction perpendicular to the general plane of the molded member 200). Form the suspended portion 219 described above.

[0143] Other moldings containing a plurality of suspended portions can be made by differential cross-linking of a layer of photosensitive resin or other curable material through a mask containing transparent and opaque regions. This opacity includes areas having differential opacity, for example, consisting of relatively high opacity (opaque like black) and relatively low opaque areas (i.e., some transparency).

When the cured layer having the filament receiving side and the opposing second side is exposed to curable radiation through a mask adjacent the filament receiving side of the coating, the opaque areas of the mask expose the first area of the coating to the curable radiation. To prevent curing of the first zone of the coating through the entire thickness of the coating.
The partially opaque area of the mask only partially blocks the second area of the coating so that the radiation is less than the thickness of the coating (starting from the filament receiving side of the coating and going to the second side). It is possible to cure the second area to a thickness. The transparent area of the mask leaves an unblocked third area so that curing radiation can cure the third area through the entire thickness of the coating.

As a result, the uncured material can be removed from the partially formed member. The resulting cured framework includes a filament contacting side 201 formed from the filament receiving side of the coating and a back surface 20 formed from the second side of the coating.
2 The resulting framework includes a back surface 202 and a plurality of bases 211 formed from a third area of the coating, and a plurality of suspensions including a web contact side 201 and formed from a second area of the coating. It has a part 219. The plurality of bases may include a substantially continuous pattern, a substantially semicontinuous pattern, a discontinuous pattern, or any combination thereof, as described above. The suspension 219 extends from a plurality of bases at an angle (usually about 90 ^° , but not absolutely),
And, at a distance from the rear face 202 of the resulting framework, a void space is formed between the suspension and the rear face. Typically, the use of a molded member 200 that includes a reinforcing element 250 results in a void space 2
15 is formed between the suspension 219 and the reinforcement element 250 (FIG. 6).

In the next step, a plurality of pseudo-thermoplastic starch filaments are deposited on the filament contacting side 201 of the molded member 200 (FIG. 7-9), and the plurality of starch filaments are at least partially formed in the three-dimensional pattern of the molded member 200. Make sure you adapt. Referring to the embodiment shown schematically in FIG. 7, when the starch filament 17b exits the drawing device, the three-dimensional filament contact side 201 of the molded member 200
Deposit on top. In an industrial continuous apparatus, the molding member 20
0 includes an infinite belt that moves continuously in the longitudinal direction MD as shown in FIG. The starch filaments are then tied together and intertwined through various conventional techniques. U.S. Pat. No. 5,688,468 (to Lu, Nov. 18, 1997) teaches a method and apparatus for making spunbond nonwoven webs containing filaments of reduced diameter, the disclosure of which is incorporated herein by reference. I do.

In another embodiment, a plurality of filaments are first deposited on the forming member 500 instead of the forming member 10 (FIG. 9). This step is optional and can be used to facilitate equalization of the base weight of the plurality of starch filaments through the width of the structure 10 to be made. Wire forming member 500
May be considered in the case of the present invention. In the example of the embodiment shown in FIG. 9, the forming member 500 includes rollers 500a and 5a.
Move around 00b in the vertical direction. The forming member is fluid-permeable, and a pressure reducing device 550 is placed below the forming member 500. When a pressure difference is applied to a group of starch filaments arranged thereon, more or less of the starch filament passes through the receiving surface of the forming member 500. A more or less flat distribution is promoted.

If desired, various irregularities can be formed in the starch filament using the forming member 200, particularly on the filament surface. For example, the filament receiving surface of the forming member may be composed of various sharp ends (not shown), and the starch filament arranged thereon may be imprinted while relatively soft, and a notch may be formed in the starch filament (see FIG. 11). Schematic)) or create other irregularities. This is advantageous for the flexible structure 100.

In the embodiment of FIG. 9, a plurality of filaments can be conveyed from forming member 500 to forming member 200 by any conventional technique known in the art, such as vacuum shoe 600, to forming member 200, in this case. In addition, a sufficient pressure is applied to the vacuum shoe so that the plurality of starch filaments deposited on the forming member 500 can be separated and adhere to the forming member 200.

In the continuous manufacturing method of the flexible structure 100, the forming member 200 can have a linear velocity lower than the linear velocity of the forming member 500. The use of this type of speed difference at the transfer point is well known in the papermaking industry and can be used for so-called "microshrinks" which are usually believed to be effective when applied to low consistency wet webs. U.S. Patent No. for purposes of describing the principle mechanism for microshrinkage
The disclosure of US Pat. No. 4,440,597 is incorporated herein by reference, which details details on “wet microshrinking”. Briefly, micro-shrinking involves transporting a web with low fiber consistency from a first member (such as a perforated member) to a second member (such as a loop of open weave fabric) that is slower than the first member. Is included. If multiple starch filaments can be maintained under sufficiently flexible conditions until the time when a starch filament is formed and transferred from a relatively slow support to a relatively fast support, the plurality of starch filaments can be micro-shrinked. This can be effectively performed, and the depth of the flexible structure 100 can be reduced. The speed of the forming member 200 exceeds the speed of the forming member 500 by about 1% to about 25%.

FIG. 9A shows an embodiment of the method according to the present invention.
And the starch filament is angled 1 ^o From89^o , One layer
Specifically, about 5^O From about 85^O At a certain range of angle
It is deposited on the material 200. In this embodiment, the suspension 21
It is particularly advantageous to use a molded part 200 having a 9
I can believe. Starch filament 1 to molded member 200
7a, this kind of “angled” deposition results from the suspension 21
9 and the reinforcement element,
To bring it closer to the flexible filament 17a.
And one of the void spaces 215 formed by the starch filament.
Layers can promote easy charging. In FIG. 9A, the upstream void space
215a and the downstream void space 215b
The gap space 219 is the corner of the filament to the molded member 200.
In order to benefit from heavy deposition, starch starch
The deposit 17a is deposited on the molded member 200 in two steps. Molding
The unique figure of the member 200, especially the figure of the suspension 219 and
Downstream angle A is equal to upstream angle B, depending on
Can be different or different.

A plurality of starch filaments are
Immediately after being deposited on the filament contact side 201, the filaments at least partially conform to the three-dimensional pattern. In addition, various methods for inducing or promoting adaptation of the starch filament to the three-dimensional pattern of the molded member 200 can be used. One method is to apply a fluid differential pressure to multiple starch filaments.
This method is advantageous when the molded member 200 is fluid-permeable. For example, the vacuum device 550 provided on the back surface 202 of the fluid-permeable molded member 200
And applying a vacuum to a group of starch filaments arranged thereon. Under the effect of reduced pressure, some of the starch filaments may deflect into openings 220 and / or void spaces 215 of molded member 200,
Otherwise, it can adapt to the three-dimensional pattern.

It is believed that all three regions of the flexible structure 100 can generally have equal base weights. By deflecting a portion of the starch filament into the opening 220, the density of the product pillow 120 can be increased relative to the density of the first imprint area 110. The region 110 that does not deflect into the opening 220 can be stamped by compressing the flexible structure during the compression nip. When the seal is applied, the seal area 1
The density of 10 is higher than the density of the pillow portion 120 and the third region 130. Region 11 not deflected into opening 220
The density of 0 and the density of the third region 130 are higher than the density of the pillow portion 120. The density of the third area should indicate an intermediate density between the densities of the seal area 110 and the pillow 120.

Referring to FIG. 1A, it is believed that the flexible structure 100 according to the present invention has three different densities. The highest density area is the high density printing area 110. The position and the shape of the stamped area 110 are the same as those of the molded member 200.
Corresponding to the framework 210. The lowest density region of the flexible structure 100 should be the region of the pillow 120 whose location and graphics correspond to the openings 220 of the molded member 200.
Third region 1 corresponding to syncline portion 230 in molded member 200
30 has a density intermediate between the density of the pillow portion 120 and the density of the seal area 110. The “syncline” section 230 is the molded member 2
00 form a surface of a framework 210 having a directional vector component extending from a filament receiving side 201 toward a back surface 202. The synchro 230 does not extend completely through the framework 210, as does the opening 220. Thus, the difference between the synchro 230 and the opening 220 is that the opening 220 represents a through hole in the frame 210 while the synchro 23
0 represents a blind hole, crack, or notch in the framework 210.

The third region of the structure 100 according to the present invention
It will be arranged with three different bumps. As used herein, the term “elevation” of a region refers to the distance from a reference plane (ie, the XY plane). For convenience, the reference plane can be viewed visually as horizontal, in which case the vertical distance from the reference plane is vertical. The elevation of a particular area of the starch filament structure 100 can be measured using any non-contact measurement method known in the art suitable for this purpose. A particularly preferred measuring method is a non-contact laser displacement sensor having a beam of 0.3 × 1.2 millimeter size in the 50 millimeter range. A suitable non-contact laser displacement sensor is ID "MX1A / B"
Commercially available from ec Company. Alternatively, the bump difference can be measured using a contact stylis gauge known in the art. A gauge of this type is described in U.S. Pat. No. 4,300,981 (to Carstens), incorporated herein by reference. When the structure 100 according to the present invention is placed on the reference line using the marking area 110 that contacts the reference plane, the pillow 120 and the third area 130 extend vertically from the reference plane. The elevation differences in regions 110, 120 and 130 are also shown in FIG.
As shown in A, it can be formed by using a molded member 200 having a depth difference or a three-dimensional pattern raised difference. This type of three-dimensional pattern having a depth difference / elevation difference can be made by polishing a preselected part of the molded part. Further, the molded member 200 made of a crosslinked material can be made using a three-dimensional mask. By using a three-dimensional mask with recess / projection depth / elevation differences, a corresponding framework 210 with elevation differences can also be created. Other conventional techniques for forming surfaces with raised ridges can also be used for the above purpose.

To mitigate any adverse effects that may occur due to the sudden application of the fluid pressure differential applied by the decompression device 550 (FIGS. 8 and 9) or the decompression pickup shoe 600 (FIG. 9), the back of the molded member is "projected""To form a microscopically irregular surface. Sudden application of a fluid pressure differential may result in some or some of the filament being pushed through the entire forming member 200, forming a so-called "pinhole" in the resulting flexible structure. The microscopic irregularities described above may also be advantageous for some embodiments of shaped member 200. The reason is that the formation of a vacuum seal between the back surface 202 of the molding member 200 and the surface of the papermaking device (for example, the surface of the vacuum device)
These prevent, thereby creating a "leakage" between them, resulting in the undesired results of reduced pressure application in the "through-air-drying" method for manufacturing flexible structures in the present invention. This is because it is alleviated.
Another method of creating this type of leak is described in US Pat. No. 5,718,806.
No. 5,741,402; No. 5,744,007; No. 5,776,
No. 311; No. 5,885,421, which are incorporated herein by reference.

The above-mentioned leakage is a so-called “differential light transmission technique (deff).
erential light transmussion techniques) "(US Patent No. 5,624,790;
5,554,467; 5,529,664; 5,514,523;
No. 5,334,289, which are incorporated herein by reference). The molded part can be made by applying a light-sensitive resin coating to a reinforcing element having opaque portions and then exposing the coating to activating wavelength light through the transparent and opaque areas and / or through the reinforcing element.

Another method of creating backside irregularities is to use a patterned forming surface or a patterned barrier film (US Pat.
No. 4,504; 5,260,171; 5,098,522, which are incorporated herein by reference). The molded member casts a photosensitive resin over and through the reinforcement element while the reinforcement element moves over the textured surface, and then coats the activation wavelength light through a mask having transparent and opaque regions. Can be made by exposure.

As seen in vacuum device 550, a reduced pressure may be applied to a series of filaments through fluid permeable molded member 200, or a plurality of filaments may be applied to the molded member using a fan that applies a positive pressure to the plurality of filaments. 3
Deflection during a three-dimensional pattern can be facilitated.

Further, FIG. 9 is a schematic diagram illustrating an optional step of the method according to the present invention, in which a flexible sheet material 800 having an infinite band that is transported around rollers 800a and 800b and contacts a plurality of filaments. Use to stack multiple starch filaments. That is, a plurality of filaments are formed by molding member 200 and flexible sheet material 80.
Between 0 and a certain period of time. Flexible sheet material 800
Has a permeability less than the air permeability value of the molded member 200,
In some embodiments, it is air impermeable. When the fluid pressure difference P is applied to the flexible sheet 800, at least a part of the flexible sheet 800 faces the three-dimensional pattern of the molded member 200,
In some cases, the deflection may occur into the three-dimensional pattern, thereby allowing the plurality of starch filaments to closely conform within the three-dimensional pattern of the molded member 200. U.S. Pat. No. 5,893,965 describes a basic arrangement of an apparatus and method utilizing a flexible sheet material.

In addition to or separately from the fluid pressure differential, mechanical pressure can also be used to facilitate the formation of a three-dimensional microscopic pattern of the flexible structure 100 according to the present invention.
Such a mechanical pressure can be created by any suitable pressing surface, for example with a roller surface or a band surface. FIG. 9 shows two example embodiments of the pressing surface. One or several pairs of pressure rollers 900a and 900b and 900c and 900d are used to press the starch filaments arranged on the molding 200 so as to more completely conform to the three-dimensional pattern. If desired, for example, the pressure created between rollers 900c and 900d may be applied to rollers 900a and 900b.
The pressure exerted between the pressure rollers can be graded so as to be even greater than the pressure between them. Alternatively and / or in addition, an infinite pressure band 950 that moves about rollers 950a and 950b may be pressed against a portion of the filament side 201 of the forming member 200 to create a flexible structure therebetween. You can also seal.

The pressing surface is a surface having a smooth or unique three-dimensional pattern. In the latter case, the pressing surface is used as an embossing device to form a microscopic pattern consisting of distinct protrusions and / or depressions in the flexible structure, jointly or independently of the three-dimensional pattern of the molding 200. Further, the pressure surface may be used to deposit various additives, such as, for example, softeners and inks, on the flexible structure 200. For example, ink roller 910 or spray device (or shower)
Various additives may be deposited directly or indirectly on the flexible structure 200 using conventional techniques such as 920.

The structure 100 can be arbitrarily reduced in depth as is known in the art. Depth reduction can be accomplished by creping the structure 100 from a rigid surface, more specifically from a cylinder such as, for example, the cylinder 290 shown schematically in FIG. Creping is performed using a doctor blade 292 known in the art. Creping can be performed in accordance with the disclosure of U.S. Pat. No. 4,919,756 to Sawdai, issued April 24, 1992,
This disclosure is incorporated herein by reference. Alternatively or additionally, depth reduction can be achieved using micro-shrinkage as described above.

The flexible structure 100 having a reduced depth is usually
It is easier to stretch in the vertical direction than in the horizontal direction, and easily bends around the hinge line formed by the depth shortening method. This hinge line generally extends in the lateral direction, ie, along the width of the flexible structure 100. It is contemplated that flexible structures 100 that do not crepe and / or otherwise shorten in depth are also within the scope of the present invention.

Various products can be made using the flexible structure according to the present invention. Applications found in products include air, oil and water filters; vacuum cleaner filters; furnace filters; face masks; coffee filters; tees or coffee bags; heat insulating materials and noise barriers; Nonwoven fabric for disposable hygiene articles such as incontinence articles; biodegradable woven fabrics with improved moisture absorption and softness, such as microfiber or breathable woven fabrics; charged structure webs for dust collection and removal; wrapping paper , Writing paper, newsprints, reinforced papers and reinforced webs for hard paper such as reinforced paperboard, and webs for tissue-grade papers such as toilet paper, paper towels, napkins and decorative paper; surgical drapes, wound dressings, bandages ,
Medical supplies such as dental patches and self-dissolving sutures; and dental supplies such as dental floss and toothbrush bristles. Examples of flexible structures also include odor absorbers, termite repellents, insecticides, rodenticides and other specialty products. The articles made can absorb water and oil and can be used for cleaning water and oils, or find use as water retention and release and control materials for agricultural or horticultural applications. Starch fibers or fiber webs are mixed with other materials such as sawn dust, wood pulp, plastics and concrete to make building materials such as wall materials, support beam materials, compressed paperboard, dry walls, backing materials and ceiling tile materials. Other medical applications such as casts, splints and tongue depressors; and can be homogeneously mixed into composite materials that can be used as fireplace logs for decorative and / or burning purposes.

Test Method A. Shear viscosity The shear viscosity of this composition was measured using a pore viscometer (Rheograph 2003).
Mold, manufactured by Goettfert). This measurement is
The diameter D is 1.0 mm and the length L is 30 mm (ie, L
/ D = 30). Attach this die to the lower end of the barrel and set the barrel to the test temperature range of 25 ° C.
To 90 ° C. The sample composition reheated to this test temperature (t) is loaded into the barrel of the viscometer and substantially fills the barrel (using about 60 grams of sample). The barrel is heated to a specific temperature (t). If air bubbles form on the surface after sample loading, the air is removed from the sample with the composition prior to the start of the test. The piston is programmed in such a way that the sample is pushed out of the barrel at a set speed through the pore die. As the sample exits the barrel through the pore die, the sample experiences a pressure drop. The apparent shear viscosity is calculated from this pressure drop and the flow rate through the pore die. When this log log (apparent shear viscosity) is plotted against log (shear rate), the plot follows the power law η = Kγ ^n-1 (K is the material constant, γ is the shear rate). The reported shear viscosity of the composition in the present invention is an extrapolation of a shear rate of 3000 s ^-1 using this power law relationship.

B. Extensional viscosity The extensional viscosity is measured using a pore viscometer (Rheograph 2003, Goettfer
t). This measurement is based on the initial diameter (D
_initial ) 15mm, final diameter (D _final ) 0.75m
This is performed using a semi-hyperbolic die having a length of 7.5 mm (m) and a length (L) of 7.5 mm.

The semi-hyperbolic form of the die is defined by two equations. Z is the axial distance from the initial diameter, D
(Z) is the die diameter at a distance z from D _initial ;

(Equation 2)

The die is attached to the lower end of the barrel and held at a fixed test temperature (t) corresponding to the temperature at which the starch composition is to be processed. This test temperature (processing temperature) is a temperature above the melting point of the sample starch composition. Loading the sample starch composition preheated to the die temperature into the viscometer barrel,
Substantially fills the barrel. If air appears on the surface after loading, the composition is taken up from the molten sample with the composition prior to conducting the test to exclude air. The piston is programmed in such a way that the sample is pushed out of the barrel at a set speed through the pore die. As the sample exits the barrel through the pore die, the sample experiences a pressure drop. From this pressure drop and the flow rate of the sample through the die, the apparent extensional viscosity is calculated according to the following equation. Extension viscosity = (delta P / extension rate / E _h ) · 10 ⁺⁵ where extension viscosity is Pascal-second, delta P is pressure drop (bar), and extension rate is the flow rate of the sample through the die ( sec ⁻¹ ), and E _h is a dimensionless Hencky distortion. Hencky distortion is a time or history dependent distortion.
The distortion experienced by a fluid element in a non-Newtonian fluid depends on its motion history, ie,

(Equation 3) Hencky strain in the case of this design (E _h) is a 5.99 defined by the _{equation; E h = l n [(} D initial / D final) 2]

[0170] The apparent extensional viscosity is reported as a function of extension rate of 250 ^-1 using the law relationship of the power. A detailed disclosure of elongational viscosity measurement using a semihyperbolic die is described in U.S. Pat.
No. 5,357,784 (Collier, Oct. 25, 1994), the disclosure of which is incorporated herein by reference.

C. The weight average molecular weight of the molecular weight and molecular weight distribution of starch (M _W) and molecular weight distribution (MW
D) is measured and determined by gel permeation chromatography (GPC) using a mixed bed column. The components of the instrument are as follows: Pump Waters 600E System controller Waters 600E Automatic sampler WAters 717 Plus Column 600 mm long, 7.5 mm inner diameter PL gel 20 μm Mixed A column (gel molecular weight range 1000 to 40,000,000) Detector Waters 410 Differential Refractometer GPC Software Waters Millenium ^R Software

Molecular weights 245,000; 350,000; 480,000; 805,
Calibrate the column with 000; and 2,285,000 Dextran standards. These dextran calibration standards are from American Polymer Standards Corp., Men
Commercially available from tor, OH. An assay standard is prepared by dissolving a calibration substance in a mobile phase to make a solution of about 2 mg / ml. The solution is allowed to stand overnight. Then shake lightly (5m
1. Syringe filter (5 μm nylon membrane “Spartan-25”, VWR) using “Norm-Ject” (commercially available from VWR)
(Commercially available from the company).

[0173] Starch samples are prepared by first making a 40% by weight starch mixture in tap water, which is heated to gelatinize the starch mixture. 1.55 grams of the gelatinization mixture was then added to 22 grams of the mobile phase and 3
Make a mg / ml solution, this preparation is stirred for 5 minutes,
Place the mixture in a 105 ° C. oven for 1 hour, remove the mixture from the oven, and then cool to room temperature. The solution is filtered using a syringe and a syringe filter as described above.

100 μl of the filtered standard or sample solution
The previous test material is flushed out by the automatic sampler during the injection loop of and the current test material is injected into the column. The eluted sample from the column is measured against a mobile phase background with a set sensitivity range 64 by a differential refractometer kept at 50 ° C. The mobile phase is DMSO with 0.1% W / V LiBr dissolved. Set the flow rate to 1.0 ml / min,
And in isocratic mode (ie, the mobile phase remains unchanged during operation). Each standard and sample is passed through GPC three times and the results are averaged. The molecular weight distribution is calculated as follows: MWD = weight average molecular weight / number average molecular weight

D. Thermal Properties The thermal properties of the starch composition according to the present invention are determined based on the melting point (start) of 156.6 ° C. and the heat of fusion of 6.80 c reported in the chemical literature.
al. Determined by measuring with a TA Instruments "DSC-2910" calibrated using an indium metal standard substance having an indium / g standard. The operation of the standard DSC follows the operating instructions of the equipment manufacturer. In preparation for the generation of volatiles (e.g., water vapor) from the starch composition during the DSC measurement, a large capacity pan with an o-ring seal is used to prevent volatilization of the volatiles from the sample pan. The sample and inert control (usually an empty pan) are heated at the same rate in a controlled environment. When a real or quasi-phase change occurs in the sample, the DSC instrument measures the heat flow from the sample to the inert control. The device is connected to a computer for control of test parameters, data collection, calculation and reporting.

The sample is weighed into a pan and the o-phosphorus and cap are closed. Typical sample volumes are 25 to 65 milligrams. Place the closed pan in the apparatus and program the computer as follows for the purpose of thermal property measurement: Equilibrate at 1.0 ° C. Hold for 2 minutes at 2.0 ° C. 3. 10 ° C./120° C. / 4. Heat at 120 ° C. for 2 minutes 5. Cool to 30 ° C. at 10 ° C./min. 6. Equilibrate at room temperature for 24 hours, remove the sample pan from the DSC device and place it in a controlled environment at 30 ° C. during this period; Return the sample pan to the DSC and equilibrate at 0 ° C 8.2 hold 9. Heat at 120 ° C at 10 ° C / min 10. Hold at 120 ° C for 2 minutes 11. Cool to 10 ° C at 10 ° C / min, and 11. equilibration; and Take out the working sample. The computer calculates and reports the result of the thermal analysis as differential heat transfer (ΔH) with respect to temperature or time. Normal,
This differential heat transfer is based on weight (ie, cal./m
g) is normalized and reported. If the sample exhibits a quasi-phase transition, such as a glass transition temperature, the ΔH differential with respect to the time / temperature plot can be employed to further facilitate the measurement of the glass transition temperature.

E. Preparation of the water-soluble sample composition is carried out by mixing the components by heating and stirring until a substantially homogeneous mixture is formed. Spread the molten composition to "Teflon ^R" sheet casting a thin layer film is cooled to room temperature. The film is then completely dried in an oven at 100 ° C. (ie, until there is no moisture in the film / composition). Equilibrate the dried film to room temperature. Grind and pelletize the equilibrated film. To determine the% solids in the sample, the ground sample is placed in a pre-weighed metal pan and the total weight of the pan and sample is recorded. 10 weighed pans and samples
Leave in 0 ° C. oven for 2 hours, then remove and weigh immediately. The solids (%) is calculated as follows:

For the purpose of determining the solubility of the sample composition, 10 g of the ground sample is weighed into a 250 ml beaker. Add deionized water to bring the total to 100 g. Mix sample and water on a stir dish for 5 minutes. After stirring, pour at least 2 ml of sample into the centrifuge tube. 10 hours at 20,000g for 1 hour
And centrifuge. Collect the supernatant of the centrifuged sample,
Read the refractive index. Calculate the solubility (%) of the sample as follows:

F. Condition the film sample at 48% to 50% relative humidity and at a temperature of 22 ° C to 24 ° C until the moisture content of the film sample is about 5% to about 16% prior to the caliper test. Moisture content is TG
It is measured and determined by A (Thermo Gravimetric Analysis; thermogravimetric analysis). For thermogravimetric analysis, a high-resolution “YGA 2950” thermogravimetric analyzer from TA Instruments is used. Weigh about 20 mg of sample into a TGA pan. Place sample and pan into unit according to manufacturer's instructions and heat to 250 ° C. at a rate of 10 ° C./min. Moisture in sample (%)
Is determined from the weight loss and the initial weight as follows:

The sample whose condition has been adjusted in advance is cut into a size exceeding the size of a leg (foot) used for caliper measurement. The legs used are annular with an area of 3.14 square inches. The sample is placed on a horizontal plane and the sample is sealed between this plane and the load leg having a horizontal load surface. The loading leg loading surface in this case has an annular surface area of about 3.14 square inches and provides a sealing pressure of about 15 g / cm ^{2 on} the sample. The caliper is a gap created between the load leg load surface and the plane. This type of measurement is provided by Thwing-Albert, Philadelphia, P
a.VIR Electronic Thickness Tester Mode
l II ”can be used. The results are reported in mils. Divide the total number of readings recorded in the caliper test by the number of recorded readings. Report the results in mils.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an embodiment of a flexible structure according to the present invention.

FIG. 1A is a schematic sectional view taken along line 1A-1A of FIG. 1;

FIG. 2 is a schematic plan view showing another embodiment of a flexible structure according to the present invention.

FIG. 3 is a schematic sectional view showing another embodiment of a flexible structure according to the present invention.

FIG. 4 is a schematic plan view showing an embodiment of a molded member that can be used for manufacturing a flexible structure according to the present invention.

4A is a schematic cross-sectional view taken along line 4A-4A of FIG. A.

FIG. 5 is a schematic plan view of another embodiment of a molded member that can be used for forming a flexible structure according to the present invention.

FIG. 5A is a schematic cross-sectional view taken along line 5A-5A of FIG. A.

FIG. 6 is a schematic plan view of another embodiment of a molded member that can be used for forming a flexible structure according to the present invention.

FIG. 7 is a schematic partial schematic side view and schematic partial cross-sectional view of an embodiment of the electrospinning method.

FIG. 7A is a schematic diagram of FIG. 7 taken along line 7A-7A.

FIG. 8 is a schematic side view showing an embodiment of the method of the present invention.

FIG. 9 is a schematic side view of another embodiment of the present invention.

FIG. 9A is a schematic side view and a partial view of another embodiment of the present invention.

FIG. 10 is a schematic illustration of a fragment of one embodiment of a starch filament having a differential cross section perpendicular to the major axis (long axis) of the filament.

FIG. 10A is a schematic diagram illustrating some examples of non-exclusive embodiments of a starch filament cross-section.

FIG. 11 is a schematic cross-sectional view of a starch filament having a plurality of notches for at least a portion of the filament length.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Starch filament manufacturing apparatus 11 Housing of 10 12 Heating fluid cavity 13 Die head 14 Jet nozzle 15 Air (annular) orifice 16 Air (discrete) orifice 17 Starch composition 17a Starch filament 100 The first region of flexible structure 110 100 120 100 second region (pillow in one embodiment) 130 300 third region 115 100 substantially void space (pocket) in 100 (between cantilever wing portion and first region) 128 dome portion 129 100 Of cantilever wing portion 200 Molded member 201 Filament receiving side of 200 202 Back surface of 200 210 Frame 211 First layer (multi-layer structure) 212 Second layer (---------) 215 219 and 250 Void space between 219 Suspended part 220 Opening 230 Slope 250 Reinforcement element 2 90 (for crepe) cylinder 292 crepe knife 500 forming member 550 vacuum device 600 vacuum pickup shoe 800 flexible sheet of material (deflection of lowermost platform) 900a-900c pressure roller 910 ink roller 920 spray device (shower) 950 Press band

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor David, William, Cavell Cincinnati, Ohio, USA, Pawner, Farm, Drive, 6646 F-term (reference) 4L036 MA33 PA01 4L047 AA00 BA21 CC03

Claims (34)

[Claims] 1. A flexible structure comprising a plurality of starch filaments, wherein the structure includes at least a first region and a second region, each of the first and second regions being at least one common stricture. A flexible structure, wherein at least one common intensity of the first region is different in value from at least one common intensity of the second region. 2. The method according to claim 1, wherein the common strength is density, base weight, bump,
The flexible structure of claim 1, wherein the flexible structure is selected from the group consisting of opacity, crepe frequency, and any combination thereof. 3. The method of claim 1, wherein one of the first and second regions includes a substantially continuous network, and the other of the first and second regions includes a plurality of discrete areas dispersed through the substantially continuous network. Item 2. A flexible structure according to Item 1. 4. The flexible structure according to claim 1, wherein at least one of the first and second regions comprises a semi-continuous network. 5. The intensity of the first region and the intensity of the second region further include at least a third region having at least one intensity that is common and different in its value.
The flexible structure according to claim 1. 6. The flexible structure according to claim 5, wherein at least one of the first, second and third regions comprises a substantially continuous network. 7. The flexible structure according to claim 5, wherein at least one of the first, second, and third regions includes a discontinuous area. 8. The flexible structure according to claim 5, wherein at least one of the first, second, and third regions includes a substantially semi-continuous area. 9. The flexible structure according to claim 5, wherein at least one of the first, second, and third regions includes a plurality of discrete areas dispersed through a substantially continuous network. 10. A flexible structure comprising a starch filament, the structure including at least a substantially continuous network region and a plurality of discrete regions dispersed through the substantially continuous network region. A flexible structure in which the continuous network region is relatively dense compared to the relatively low density of the plurality of discrete areas. 11. When the structure is disposed on a horizontal reference plane, the first region defines a first ridge, and the second region extends outward from the first region to define a second ridge. The flexible structure according to claim 1, wherein 12. When the structure is disposed on a horizontal reference plane, the first region defines a first ridge, the second region defines a second ridge, and the third region defines a third ridge. 6. The flexible structure according to claim 5, wherein the compartment comprises at least one of the first, second and third ridges is different from at least one of the other ridges. 13. The flexible structure according to claim 12, wherein the second ridge is intermediate between the first and third ridges. 14. The second region includes a plurality of starch pillows, at least some of the pillows extending from the first ridge to the second ridge, and laterally from the dome to the second ridge. The flexible structure of claim 11, comprising a cantilever wing that extends. 15. The density of the starch cantilever portion is intermediate between the density of the first region and the density of the dome portion.
A flexible structure according to claim 1. 16. The flexible structure according to claim 14, wherein the cantilevered wing portion is higher than the first surface to form a substantially hollow space between the first region and the cantilevered wing portion. 17. The flexible structure according to claim 1, wherein at least some of the plurality of starch filaments have a size of 0.001 dtex to 135 dtex. 18. The flexible structure of claim 1, wherein at least some of the plurality of starch filaments have a size between 0.01 dtex and 5 dtex. 19. A flexible structure comprising a plurality of starch filaments, the flexible structure comprising the following steps: melt spinning, dry spinning, wet spinning, electrospinning, or any combination thereof. Forming a plurality of starch filaments; providing a fluid permeable molded member including a reinforcing element connected to a patterned resinous frame having at least one opening, wherein the frame has a structure for receiving the plurality of starch filaments thereon. A filament receiving side and a back side facing the filament receiving side, wherein the reinforcing element is located between the filament receiving side and at least a part of the framework rear side, and the filament receiving side has a substantially continuous pattern; Including a continuous pattern, a discontinuous pattern, or any combination thereof; a plurality of starch filaments deposited on the filament receiving side of the molded member; Filaments at least partially acclimated to filament-receiving side of the pattern of the framework; the fluid pressure differential in addition to a plurality of starch filaments, thereby, the plurality of filaments supported by the patterned framework 1
Forming an area and a second area of the plurality of starch filaments deflecting into the at least one opening and supported by the reinforcing element; and separating the plurality of starch filaments from the molded member, thereby forming the first area. And the second
Forming a flexible structure comprising the region; 20. A method of making a flexible structure containing starch filaments, the method comprising the steps of: (a) providing a plurality of starch filaments; (b) a filament receiving side and a back surface opposite thereto. Preparing a shaped member having: a filament receiving side in this case having a three-dimensional pattern therein; (c) depositing a plurality of starch filaments on the filament receiving side of the formed member; At least partially conforming to a three-dimensional pattern. 21. A step of preparing a molded member, wherein the three-dimensional pattern on the filament receiving side is a substantially continuous pattern, a substantially semi-continuous pattern, a pattern including separate projections, or any combination thereof. 21. The method of making a flexible structure according to claim 20, comprising preparing a molded member including mating. 22. The method of claim 21, wherein the step of preparing a molded member includes providing a molded member including a resinous frame coupled to the reinforcing element. 23. The method of claim 21, wherein the forming member preparing step includes preparing an air-permeable forming member. 24. The method of claim 21, wherein the forming member preparing step includes preparing a forming member having a suspended portion. 25. The method of claim 24, wherein the forming step comprises preparing a forming member formed by at least two layers connected in face-to-face relationship. 26. The process of depositing a plurality of starch filaments on a filament receiving side of a molded member and at least partially adapting the plurality of starch filaments to its three-dimensional pattern includes applying a fluid differential pressure to the plurality of starch filaments. 21. The method of making a flexible structure according to claim 20, comprising adding. 27. The method of claim 20, further comprising densifying selected portions of the plurality of starch filaments. 28. The method of claim 20, wherein densifying selected portions of the plurality of starch filaments comprises applying mechanical pressure to the plurality of starch filaments. 29. The step of depositing a plurality of starch filaments on the filament side of the molded member, wherein the starch filament is deposited at a steep angle thereto, wherein the steep angle ranges from about 5 degrees to about 85 degrees. 3. The method according to claim 2, which includes a step.
0. The method for producing a flexible structure according to item 0. 30. A method for preparing a plurality of starch filaments, comprising:
21. The method of making a flexible structure according to claim 20, comprising melt spinning, dry spinning, wet spinning, or any combination thereof. 31. A flexible structure according to claim 30, wherein the aspect ratio of the major axis length of at least some of the starch filaments to the equivalent diameter of the cross section perpendicular to the major axis of the starch filament is at least 100/1. Recipe. 32. The size of the starch filament is 0.001.
21. The method of making a flexible structure according to claim 20, wherein said flexible structure is from about 135 dtex to about 135 dtex. 33. The method of claim 20, further comprising the step of shortening the depth of the plurality of starch filaments. 34. The method of claim 33, wherein the step of shortening comprises creping, microshrinking, or a combination thereof.