KR100402549B1 - Electro-spinning process for making starch filaments for flexible structure - Google Patents

Abstract

Flexible structures comprising a plurality of starch filaments are disclosed. Such structures include at least a primary region and a secondary region, each of which has at least one common reinforcing property selected from the group consisting of density, basis weight, height, opacity, grape frequency and any combination thereof. The common reinforcing properties of this primary region differ in value from the common reinforcing properties of the secondary region.

Description

Electrospinning process for making starch filaments for flexible structure

The present invention relates to a flexible structure comprising starch filaments, and more particularly to a flexible structure having differential regions.

Cellulosic fibrous webs of cellulose, such as paper, are well known in the art. Low density fiber fabrics are commonly used today for things like paper towels, cosmetic tissues, napkins, wipes, and the like. The widespread demand for these paper products required advances in these products and the methods of making them. To meet this need, papermakers must balance the price of machinery and raw materials with the price of providing products to consumers.

In traditional paper making operations, the fibers of wood cellulose are repulped, beaten or refined to achieve some degree of fiber hydration to form a water pulp slurry. The process of making paper products for use in tissues, towels and hygiene products generally includes preparing a water slurry and removing water from the slurry while simultaneously rearranging the fibers to form paper tissue. Following moisture removal, the tissue is converted into product packaging through a dry roll or sheet form process. Various types of machinery should be used for the water removal and conversion operations that require significant capital contributions.

Another feature of traditional paper making operations is the addition of additives to the pulp for special final properties. For example, additives such as reinforcing resins, debonding surfactants, emollients, pigments, lattices, synthetic micro-spheres, fire-retardants, dyes, flavorings, etc. may be used in the manufacture of paper. Often used. Maintaining these additives effectively in the weaving part of the paper making process is a difficult problem for the manufacturer, since the unretained part not only causes economic losses but also causes serious pollution problems if some are spilled. Additives may also be added to the paper weaving followed by water removal through coating or saturation processes generally well known in the art. This process usually requires consuming heating energy to redry the paper after coating. In addition, coating systems in some cases raise the problem of increasing capital costs and requiring the recovery of regulated volatiles.

As much as the variety of synthetic fibers, various natural fibers other than cellulose are used to make paper. All these alternatives, however, do not provide commercially available cellulose substitutes due to their high cost, poor adhesion properties, chemical incompatibility, and difficulty in handling in the manufacturing system. Starch fibers have been suggested as replacements for cellulose in various aspects of the paper making process, but commercial attempts to utilize these starch fibers have not been successful. As a result, paper products are still mostly made from wood-based cellulose components.

Accordingly, the present invention seeks to provide a flexible structure comprising a long starch filament and a process for producing the same. In particular, the present invention provides a flexible structure comprising a plurality of starch filaments, which includes two or more regions having differential reinforcing properties for improved strength, absorbency, and softness.

The present invention also provides a method of making starch filaments. In particular, the present invention provides an electrospinning process that produces a plurality of starch filaments.

1 is a plan view showing an embodiment of the flexible structure of the present invention.

FIG. 1A is a cross-sectional view showing a plane cut along lines 1A and 1A of FIG.

2 is a plan view showing another embodiment of the flexible structure of the present invention.

3 is a cross-sectional view showing yet another embodiment of the flexible structure of the present invention.

4 is a plan view showing an embodiment of a molding member that can be used to form the flexible structure of the present invention.

4A is a cross-sectional view illustrating a plane cut along lines 4A and 4A of FIG. 4.

5 is a plan view showing another embodiment of a molding member that can be used to form the flexible structure of the present invention.

FIG. 5A is a cross-sectional view illustrating a cut plane cut along lines 5A and 5A of FIG. 5.

6 is a cross-sectional view showing another embodiment of a molding member that can be used to form the flexible structure of the present invention.

7 is an elevation view illustrating an embodiment of an electrospinning process and apparatus for making a flexible structure comprising starch filaments.

7A is a cross-sectional view taken along lines 7A and 7A of FIG. 7.

8 is an elevation showing an embodiment of a process according to the invention.

9 is an elevation showing another embodiment of the process according to the invention.

Figure 9a is a partial elevation view of another embodiment of a process according to the present invention.

FIG. 10 is a schematic diagram showing a fragment of an embodiment of starch filament having differential cross-sectional areas perpendicular to the central (length) axis of the fiber.

10A is a schematic diagram showing some exemplary embodiments of the cross-sectional area of the starch filament.

FIG. 11 is a block diagram illustrating a slice of starch having a plurality of notches along at least one portion of the filament length.

Explanation of symbols on the main parts of the drawings

10: starch filament manufacturing apparatus 11: housing

12: pupil 13: die head

14: jet nozzle 17: starch composition

100: flexible structure 200: flexible structure

210: resinous structure 250: reinforcing device

500: molding member 550: vacuum apparatus

The flexible structure includes a plurality of starch filaments. At least some of the starch filaments range in size from 0.001 dtex to 135 dtex, in particular from 0.01 dtex to 5 dtex. The ratio of the length of the main axis of the starch filament to the equivalent diameter of the cross section perpendicular to the main axis of the starch filament is at least 100/1, in particular at least 500/1, more preferably at least 1000/1, most preferably at least 5000/1 to be.

Such a structure comprises at least a primary region and a secondary region, each of which has at least one common reinforcing property selected from the group consisting of density, basis weight, height, opacity, crepe frequency and any combination thereof. At least one common strengthening property of the primary region differs in value from at least one common strengthening characteristic of the secondary region.

In one embodiment, one of the primary and secondary regions includes a substantially continuous network, and the other of the primary and secondary regions includes a plurality of discrete regions substantially distributed throughout this continuous network. In yet another embodiment, at least one of the primary and secondary regions comprises a somewhat persistent network.

The flexible structure may further include a tertiary region having at least one reinforcing property that is the same as the reinforcing properties of the primary region and the reinforcing properties of the secondary region but differs in value. In one embodiment, at least one of the primary, secondary, and tertiary regions may comprise a substantially continuous network. In another embodiment, at least one of the primary, secondary, and tertiary regions may comprise discrete or disconnected regions. In yet another embodiment, at least one of the primary, secondary, and tertiary regions may comprise substantially continuous regions to some extent. In yet another embodiment, at least one of the primary, secondary, and tertiary regions includes a plurality of discrete regions distributed substantially throughout the continuous network.

In embodiments in which the flexible structure comprises a substantially continuous network area and a plurality of discrete areas distributed throughout the substantially continuous network area, the substantially continuous network area is associated with the relatively low density of the plurality of discrete areas. It can have a relatively high density. When the structure is placed in the horizontal reference plane, the primary region defines the primary height and the secondary region extends outward from the primary region to define a secondary height that is greater (in relation to the horizontal reference plane) than the primary height.

In embodiments that include at least three regions, the primary region may define a primary height, the secondary region may define a secondary height, and the tertiary region may define the tertiary height when the structure lies in a horizontal reference plane. Can be specified At least one of the primary, secondary and tertiary heights may be different from at least one of the other heights. For example, the secondary height can fall between the primary and tertiary heights.

In one embodiment, the secondary region includes a plurality of starch pillows, each pillow comprising a dome portion extending from the primary height to the secondary height, transversely extending from the dome portion to the secondary height. It can include a cantilever portion. The density of the starch cantilever portion may be the same as or different from the density of the primary region and the density of the dome portion, or may come between the density of the primary region and the density of the dome portion. Cantilever portions are usually formed ascending from the primary plane to form a substantially empty space between the primary region and the cantilever portion.

The flexible structure provides a molding member having a three-dimensional filament receiving side configured to produce a plurality of starch filaments by melt spinning, dry spinning, wet spinning, electrospinning, or a combination thereof to receive the plurality of starch filaments. And by placing the plurality of starch filaments on the filament receiving side of the molding member such that the plurality of starch filaments at least partially follow their pattern, and by separating the plurality of starch filaments from the molding member.

Positioning the plurality of starch filaments on the filament receiving side of the molding member may include causing the plurality of starches to at least partially follow the three-dimensional pattern of the molding member. This can be done, for example, by applying differential hydraulic pressure to a plurality of starch filaments.

In one embodiment, positioning the plurality of starch filaments in the molding member includes positioning the starch filaments at an angle with respect to the filament receiving side of the molding member, wherein the acute angle is from about 5 degrees to about 85 degrees. to be.

In one embodiment, the molding member comprises a resin structure bonded to a reinforcing element. The molding member is fluid permeable, fluid impermeable or partially fluid permeable. The reinforcing device may be located between the filament receiving side and the rear portion of the resin structure. The filament receiving side may comprise a substantially continuous pattern, a substantially continuous pattern, a discontinuous pattern, or any combination thereof. The resin structure may include a plurality of holes, which may be continuous, discontinuous, or somewhat continuous, similarly and in opposition to the pattern of the structure.

In one embodiment, the molding member is formed by a reinforcing device located at a primary height, and a resin structure coupled outwardly to the reinforcing device and extending outward from the reinforcing device to form a secondary height. The molding member may comprise a plurality of interwoven yarns, felts, or a combination thereof.

When a plurality of starch filaments are placed on the filament receiving side of the molding member, due to their fluidity and / or as a result of the application of differential hydraulic pressure, the starch filaments tend to at least partially follow the three-dimensional pattern of the molding member, It forms a primary region of a plurality of starch filaments supported by a patterned structure and a secondary region of a plurality of starch filaments deflected into holes and supported by a reinforcing device.

In one embodiment, the molding member comprises suspended portions. The resin structure of such a molding member comprises a plurality of bases extending outwardly from the reinforcement device and a plurality of cantilever parts extending laterally from the base at the secondary height, thereby forming an empty space between the reinforcement device and the cantilever part. The plurality of bases and the plurality of cantilever portions here form a three-dimensional filament receiving side of the molding member. Such a molding member may be formed by at least two layers in which parts of the structure of one layer are joined together in a mutually opposite relationship corresponding to the holes of the other layer. Molding members comprising floating portions can also be formed by differential curing of the photosensitive resin layer through a mask having a pattern comprising differential opaque regions.

The process of making the flexible structure according to the present invention may further comprise increasing the density of selected portions of the plurality of starch filaments, for example by applying mechanical pressure to the plurality of starch filaments.

The process may further comprise reducing the plurality of starch filaments. Shrinkage can be accomplished by creping, microshrinkage, or a combination thereof.

The electrospinning process for making the starch filament comprises providing a starch composition having an elongation viscosity from about 50 Pa.s to about 20,000 Pa.s (Pascals second), and electrospinning the starch composition, followed by about 0.001 dtex Producing starch filaments having a size up to about 135 dtex. Electrospinning the starch composition usually consists of electrospinning the starch composition through a die.

In starch compositions starch has a molecular weight of average weight from about 1,000 to about 2,000,000, and the starch composition has capillary numbers of at least 0.05, more precisely, at least 1.00. In one embodiment, the starch composition comprises from about 20% to 99% amylopectin by weight. The starch in the starch composition may have a molecular weight of average weight from about 1,000 to 2,000,000. The starch composition may comprise a high molecular weight polymer having a molecular weight of at least 500,000 average weight.

The starch composition may comprise from 10% to 80% by weight starch, the additive may comprise from 20% to 90%. Such starch compositions may have an elongated viscosity from about 100 Pa · s to about 15,000 Pa · s at temperatures from about 20 ° C. to about 180 ° C.

The starch composition may comprise from about 20% to about 70% starch and from about 30% to about 80% additive. Such starch compositions may have an elongated viscosity from about 200 Pa · s to about 10,000 Pa · s at temperatures from about 20 ° C. to about 100 ° C.

Starch compositions having elongated viscosities from about 200 Pa · s to about 10,000 Pa · s may have capillary numbers of about 3 to about 50. More specifically, starch compositions having elongated viscosities from about 300 Pa · s to about 5,000 Pa · s may have capillary numbers of about 5 to about 30.

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

The starch composition may comprise an additive selected from the group consisting of plasticizers and diluents. Such starch compositions may further comprise from about 5% to about 95% by weight protein, wherein the protein comprises corn protein, soy protein, wheat protein or a combination thereof.

The process of making the starch composition may further comprise the step of thinning the starch composition into an air outlet.

In one embodiment, the process for forming a flexible structure comprising a starch composition comprises providing a starch composition having an elongated viscosity of about 100 Pa.s to about 10,000 Pa.s, and in a substantially continuous pattern. Providing a molding member having a three-dimensional filament receiving side comprising a substantially continuous pattern, a discontinuous pattern, or a combination thereof and a back side facing it, electrospinning the starch composition to produce a plurality of starch filaments And positioning the plurality of starch filaments on the filament receiving side of the molding member along a three-dimensional pattern on the filament receiving side.

During the process, the molding member moves continuously in the machine direction.

The terminology used herein is defined as follows.

A "flexible structure comprising starch filament" or simply a "flexible structure" means a plurality of mechanically related pieces that are mechanically related to each other to form sheet-like products having certain fine geometric, physical and aesthetic properties. An array containing starch filaments.

A "starch filament" is a thin, thin, very resilient object that contains starch and has a very long major axis and a major axis compared to two mutually orthogonal fiber axes perpendicular to this major axis. The ratio of the major axis length to the uniform diameter of the fiber cross section perpendicular to the major axis is greater than 100/1, more specifically, greater than 500/1, more specifically, greater than 1000/1, most preferably Is greater than 5000/1. Starch filaments may include other materials, such as water, plasticizers and other optional additives.

The term "equivalent diameter" is used herein to define the surface and cross-sectional areas of individual starch filaments, regardless of the shape of the cross section. The equivalent diameter is a parameter that satisfies the equation S = 1 / 4πD ² , where S is the cross-sectional area of the starch filament (regardless of its geometry), π = 3.014159, and D is the equivalent diameter. For example, a cross section having a rectangular shape formed by two sides "A" facing each other and two sides "B" facing each other may be expressed as S = A × B. At the same time, this cross sectional area can be represented by a circular area having an equal diameter D. Thus, the equivalent diameter D can be calculated by the equation S = 1 / 4πD ² , where S is a well-known region of the rectangle. (Of course, the equivalent diameter of the circle is the actual diameter of the circle.) The equal radius is 1/2 of the equivalent diameter.

Pseudo-thermoplastics associated with "materials" or "compositions" are represented by materials and compositions that dissolve in a suitable solvent under the influence of elevated temperatures, otherwise they are flexible structures It is expressed in materials and compositions that can be softened at such temperatures that can be in a fluid state that can be shaped as desired, more clearly, to produce starch filaments suitable to form a polymer. Heating and pressure can be formed under the combined effect: Similar thermoplastics differ from thermoplastics in that the softening and liquefying of the similar thermoplastic occurs by the presence of a softener or solvent, without which temperature Smooth or fluid needed to make shape by pressure The only difference is that it is impossible to make phosphorus, because similar thermoplastics are not "dissolved" in this way.The effect of moisture content on the melting and glass transition temperatures of starch is due to It can be measured by different scanning calorimetry, as described by Zeleznak and Hosny in "Chemical Properties of Grains" Vol. 64, No. 2 (1987), pages 121-124. A pseudo thermoplastic melt is a pseudo thermoplastic in a fluid state.

Micro-geometry and its permutations refer to relatively small (i.e. extremely fine) details of a flexible structure, for example in contrast to the overall (ie macroscopic) geometry of the structure, It refers to details such as surface texture, regardless of the overall configuration of the structure. Terms including "macro" or "macro" refer to the overall geometry or part of the structure under consideration when placed in a two-dimensional array, such as the X-Y plane. For example, at the macro level, the flexible structure includes a relatively thin and flat sheet when it is placed on a flat surface. At the microscopic level, however, the structure includes a plurality of primary regions forming a primary plane having a primary height, and a plurality of domes or pillows extending outwardly from and distributed through the structural region to form a secondary height. can do.

"Intensive properties" are properties that do not have a value that depends on the set of values in the plane of the flexible structure. Common reinforcing properties are reinforcing properties owned by one or more domains. This reinforcing property of the flexible structure according to the invention includes without limitation, density, basis weight, height, opacity and crepe frequency (if the structure should be reduced). For example, if the density is a common reinforcing property of two different regions, the value of the density in one region may be different from the density value in the other region. Regions (such as primary and secondary regions) are identifiable regions that can be distinguished from one another by differing reinforcing properties.

"Basic weight" is the weight (measured in grams) of a unit area of a starch flexible structure, in which a single area is taken in the plane of the starch flexible structure. The size and shape of a single region in which the basis weight is measured depends on the relative and absolute size and shape of the regions having different basis weights.

"Density" is the ratio of the basis weight to the thickness of an area (normally taken in the plane of a flexible structure). External density is the basis weight of a sample separated by a caliper with an appropriate single transformation implemented therein. The external density used here has a unit of g / cm ³ .

"Caliper" is the visible thickness of a sample measured as described below. The sideview should be distinguished from the height of other regions, which is a fine feature of the regions.

The "glass transition temperature" Tg is the temperature at which a material changes from a viscous and elastic state to a hard and relatively fragile state.

The "machine direction" is the direction parallel to the flow of the flexible structure made through the manufacturing facility. The "cross-machine direction" is a direction parallel to the general plane of the made flexible structure and perceptual to the machine direction.

"X", "Y" and "Z" represent the traditional system of Cartesian coordinates, where the coordinates "X" and "Y" perpendicular to each other define a standard XY plane and "Z" is perpendicular to the XY plane To regulate. "Z direction" represents a direction making a crust with an X-Y plane. Similarly, the term "Z dimension" means a parameter measured parallel to the dimension, distance or Z direction. If one component, for example a molding member, is curved or not planar, the X-Y plane follows the structure of this component.

A "substantially continuous" region is an area in which one point can be connected to two other points by means of an uninterrupted line in which the length of the line is entirely extended within the area from beginning to end. This means that a substantially continuous region has substantial continuity in all directions parallel to the primary plane and only terminates at the edge of this region. The term "substantial" in relation to continuity, although absolute continuity is preferred, some degree of departure from absolute continuity, such a deviation is noticeable in the operation of the planned and intended flexible structure (or molding member). It may be tolerated while it does not.

A “substantially semi-continuous” region refers to an area that is continuity in the whole, or at least one direction, parallel to the primary plane, where the length of the line is entirely connected within the region from beginning to end. It is an area where one point cannot be connected to two other points by an uninterrupted line. Some continuous configuration may have continuity only in one direction parallel to the primary plane. Similar to the continuous region above, in the overall direction, but in at least one direction, although absolute continuity is desirable, some deviation from this continuity is detected in the operation of the structure (or deflection member). If it does not affect as much as it can, it can be tolerated.

"Discontinuous" regions refer to discrete regions that are discrete from each other that are discontinuous in all directions parallel to the primary plane.

"Absorbency" is the ability of a substance to become a fluid and to maintain such fluid through a variety of methods including capillary, osmotic, solvent or chemical action. Absorbency can be measured according to the test described herein.

"Flexibility" is the ability of a material or structure to break under a given load without breaking, regardless of the ability of the material or structure to revert to its previous deformation.

A “molding member” can be used as a support for starch filaments that can be placed in the process of making a flexible structure according to the invention, and for making (or casting) the desired microstructure of the flexible structure according to the invention. It is a structural element that can be used as a forming unit. The molding member may include without limitation any component having the ability to provide a three dimensional pattern to the structure to be produced and including a fixed plane, a belt, a woven tissue, and a strip.

A "reinforcing element" is not a preferred device or essential element that is used primarily to provide or promote the integrity, stability, and durability of a molding member comprising, for example, a resinous material. Such reinforcement devices may be fluid permeable, fluid impermeable, or partially fluid permeable, and may include a plurality of woven yarns, felts, plastics, other suitable synthetic materials, or any combination thereof.

A "press-surface" is a surface that can be pressed against the filament receiving side of a molding member having a plurality of starch filaments to at least partially deflect the starch filaments into a molding member having a three-dimensional pattern of depressions / projections. .

"Decitex" or "dtex" is a unit for starch filaments expressed in grams per 10,000 meters.

"Melt-spinning" is the process of converting a thermoplastic, or similar thermoplastic, into a fibrous material using an attenuation force. Melt spinning may include mechanical extension, melt blowing, spin bonding, and electron spinning.

"Mechanical elongation" is the process of applying force to a fiber thread that comes into contact with a running surface, such as a roll, to apply force for melting to make the fiber.

"Melt-blowing" is the process of producing fiber weaves or fiber articles directly from resins or polymers using high speed air or other suitable force to thin the fibers. In the melt blowing process, the thinning force is applied in the form of high velocity air as the material exits the die or spinneret.

"Spun-bonding" includes the process of applying a force through high velocity air or through another suitable source, causing the fiber to drop at a distance below flow and gravity.

"Electro-spinning" is the process of using dislocations as a force to thin fibers.

"Dry-spinning", commonly known as "solution spinning", involves the use of a dry solvent to stabilize fiber formation. The material is dissolved in a suitable solvent and attenuated through mechanical extension, melt ejection, spin bonding, and / or electrospinning. These fibers stabilize when the solvent evaporates.

"Wet-spinning" includes dissolving a material in a suitable solvent to form small fibers by mechanical extension, melt ejection, spin bonding, and / or electron spinning. When the fiber is formed, it enters a coagulation system which produces a stable fiber, which generally comprises a solution group filled with a solution suitable for coagulating the desired material.

A “highly compatible with starch” high polymer is a substantially homogeneous mixed composition comprising starch (ie, transparent or translucent to the naked eye when heated to temperatures above softening and / or melting temperature). It means a high molecular weight polymer capable of making a composition).

A “melting temperature” is a temperature range or higher at which the starch composite melts and softens sufficiently to be processed into starch filaments according to the present invention. Some starch compositions are analogous thermoplastic compositions and are not capable of pure "melting" action.

"Processing temperature" is the temperature of the starch composition in which the starch filaments according to the invention can be formed, for example, by attenuation.

Flexible structure

1 to 3, the flexible structure 100 comprising pseudo thermoplastic starch filaments includes at least a primary region 110 and a secondary region 120. Each of the primary and secondary regions has at least one common strengthening property, such as, for example, basis weight or density. The common reinforcement properties of the primary region 110 differ in their common reinforcement properties and values. For example, the density of the primary region 110 may be higher than the density of the secondary region 120.

The primary and secondary regions 110 and 120 of the flexible structure 100 according to the invention can also be distinguished in their microgeometry, respectively. For example, in FIG. 1, primary region 110 includes a substantially continuous network that forms a primary plane at a primary height when structure 100 lies on a flat surface, and secondary region 120 includes It may include a plurality of discrete areas distributed substantially throughout the continuous network. Such discontinuous regions include, in some embodiments, discrete protrusions or “pillows” that extend outward from the network region to form a secondary height that is greater than the primary height in relation to the primary plane. Pillows may also include a substantially continuous pattern and a substantially continuous pattern to some extent.

In one embodiment, the substantially continuous network area may have a relatively high density and the pillows have a relatively low density. In another embodiment, the substantially continuous network area may have a relatively low basis weight and the pillows have a relatively high basis weight. In yet another embodiment, the substantially continuous network area may have a relatively low density, and the pillows may have a relatively high density. In one embodiment, the substantially continuous network area may have a relatively high basis weight and the pillows have a relatively low basis weight.

In another embodiment, the secondary region 120 may comprise a network that is somewhat continuous. In FIG. 2, the secondary region 120 is shown in discrete regions similar to that shown in FIG. 1, in the XY plane (ie, the plane formed by the primary region 110 of the structure 100 lying on a flat surface). It includes some continuous regions 121 that extend in at least one direction as if falling.

In the embodiment shown in FIG. 2, the flexible structure 100 has at least one reinforcing property that is different from, but common to, the reinforcing properties of the primary region 110 and the reinforcing properties and values of the secondary region 120. The branch includes tertiary region 130. For example, the primary region 110 may have a common reinforcing property having a primary value, the secondary region 120 has a common reinforcing property having a secondary value, and the tertiary region 130 has a tertiary value. The branches may have common reinforcing properties, where the primary value may be different from the secondary value and the tertiary value may be different from the secondary value and the primary value.

As noted above, when the structure 100 comprising at least three different regions 110, 120, 130 is placed in a horizontal reference plane (such as the XY plane), the primary region 110 is of primary height. The branch defines a plane and the secondary region 120 extends therefrom to define the secondary height. In one embodiment, tertiary region 130 defines a tertiary height, wherein at least one of the primary, secondary and tertiary heights is different from at least one of the other two heights. For example, the tertiary height may be in between the primary and secondary heights.

The following table shows, without limitation, possible combinations of embodiments of the structure 100 comprising at least three regions with distinctive (ie high, medium, low) reinforcing properties. All such embodiments are included within the scope of the present invention.

Temper height middle lowness Continuous Discontinuous Discontinuous Continuous Discontinuous ---- Continuous ---- Discontinuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous Somewhat continuous ---- Somewhat continuous Discontinuous Continuous Discontinuous Discontinuous Continuous ---- Discontinuous Somewhat continuous Somewhat continuous Discontinuous Somewhat continuous Discontinuous Discontinuous Discontinuous Continuous Discontinuous Discontinuous Somewhat continuous Discontinuous Discontinuous Discontinuous Discontinuous ---- Continuous ---- Continuous Discontinuous ---- Somewhat continuous Somewhat continuous ---- Discontinuous Continuous

3 shows another embodiment of a flexible structure 100 according to the present invention, in which the secondary region 120 comprises a plurality of starch pillows, wherein at least some of the pillows are formed of starch dome portions ( 128 and a starch cantilever portion 129 extending from the starch dome portion. The starch cantilever portion 129 is raised from the XY plane and is formed between the starch dome 128 and the starch cantilever 129 extending from the primary region 110 to form substantially voids or pockets 115. Extend at an angle.

In most cases, the flexible structure 100 shown diagrammatically in FIG. 3 exhibits very high absorption properties for a given basis weight because of the presence of these substantially empty pockets 115 that can receive and contain a significant amount of fluid. It seems to be. The pocket 115 is characterized by having or not having a very small amount of starch filament therein.

Because of the process of making the flexible structure 100 as discussed below, and because of the high flowability of the flexible structure 100 and the starch filaments as a whole, some of the individual starch filaments present in the pocket 115 may be such starch. Filaments can be tolerated as long as they do not interfere with the intended pattern and intended properties of the structure 100. In this context, the term "substantially" empty pocket means that a small amount of starch filament, or a portion thereof, is due to the high flow properties of the structure 100 and the individual starch filaments comprising the structure 100. There is a tendency to admit that it can be found in. The density of the pocket 115 is 0.005 g / cc (gram per cubic centimeter) or less, in particular 0.004 g / cc or less, more preferably 0.003 g / cc or less.

In another aspect, the flexible structure 100 including the cantilever portion 129 is characterized by an enhanced overall surface area when viewed in terms of comparable structures that do not have the cantilever portion 129. The greater the number of individual cantilever portions 129 and their respective fine surface regions, the more the resulting fine specific surface region (ie the resulting fine surface region per unit of the entire macroscopic region of the structure lying on the flat surface). Grows It is recognized that the larger the absorbing surface area of the structure, the greater its absorbing capacity, and that all other parameters are equal.

In an embodiment of the structure 100 that includes the cantilever portion 129, the cantilever portions 129 may include tertiary regions of the structure 100. For example, in one embodiment, the density of the starch cantilever portion 129 falls between the density of the primary region and the density of the secondary region 120 including the dome portion. In another embodiment, the density of the dome portion 128 may come between the relatively high density of the primary region 110 and the relatively low density of the cantilever portion 129. Similarly, the basis weight of cantilever portion 129 may be equal to, intermediate, or greater than either or both of primary region 110 and dome portion 128.

Manufacturing Process of Flexible Structure

8 and 9 schematically illustrate two embodiments of a process for making a flexible structure 100 that includes starch filaments.

First, a plurality of starch filaments are provided. The production of starch filaments for the flexible structure 100 according to the present invention can be made by various techniques well known in the art. For example, starch filaments can be produced from similar thermoplastic molten starch compositions by various melt spinning processes. Starch filaments vary in size from about 0.001 dtex to about 135 dtex, more clearly from about 0.01 dtex to about 0.5 dtex.

US Patent No. 4,139,699 to Hernandez et al., Registered February 13, 1979, US Patent No. 4,853,168 to Eden et al., Registered August 1, 1989, and January 1981 There are several references, including US Pat. No. 4,234,480 to Hernandez et al., Registered 6 days. U.S. Pat.Nos. 5,516,815 and 5,316,578 to Buehler et al., Relate to starch compositions for making starch filaments using melt spinning. The molten starch composition may be extruded through the spinneret to produce a fiber with a slightly larger diameter in relation to the diameter of the die orifices of the spinneret (ie, due to the die deformation effect). The fibers are then pulled down mechanically or thermomechanically by the drawing unit to reduce the fiber diameter.

Several devices for producing non-woven thermoplastic fabric structures from extruded polymers are well known in the art and are suitable for making long flowable starch filaments. For example, the extruded starch composition may be drawn through a spinneret (not shown) that forms a curtain in the vertical direction of the starch filament facing down. The starch filaments may be pressed into the air in relation to the draw in the intake form and the weakened air slots. US Patent No. 5,292,239 to Zeldin et al., Registered March 8, 1994, discloses an apparatus for reducing turbulence in an air stream to uniformly and consistently apply a pulling force to starch filaments. This disclosure is incorporated herein by reference for the limited purpose of the method and apparatus for reducing turbulence in the air stream when making starch filaments.

In the present invention, starch filaments can be produced from compositions of starch, moisture, plasticizers, and other optional additives. For example, a suitable starch composition can be converted into a similar thermoplastic melt in an extruder and passed through a spinneret to a stretching device that forms a vertical curtain of starch filament facing down. Spinnerets may comprise assemblies well known in the art. The spinneret may comprise a plurality of nozzle bores with holes having a cross-sectional area suitable for starch filament production. The spinneret may be suitable for the flowability of the starch composition and all nozzle inner diameters, if necessary, have the same outflow rate. In addition, the outflow rate of different nozzles may vary.

A drawing device (not shown) may be located below the extrusion machine, and has an air supply manifold for supplying compressed air to the open top end, the open bottom end facing it, and the internal nozzles facing downward. It may include. As compressed air flows through the inner nozzle, the air is drawn to the open upper end of the drawing device to create a rapidly moving stream of air flowing downwards. The air flow creates a force that attracts the starch filaments to taper or deform them before they exit the open lower end of the drawing device.

It has been found that suitable starch filaments for the flexible structure 100 can be produced by an electrospinning process, in which an electrical region is applied to the starch solution to make a changed starch spray. Electron emission processes are well known in the art. In 1994, a paper entitled "The Electrospinning Process and the Application of Electrospun Fibers" by Doshi, Jayye, Natwarlal, Ph.D., explains the process of electrospinning and the forces involved in the process. The study was initiated. The paper also discloses some commercial applications of electrospun fibers. This paper is cited here for the purpose of explaining the principles of the electrospinning process.

US Patent Nos. 1,975,504 (October 2, 1934), 2,123,992 (July 19, 1938), 2,116,942 (May 10, 1938), 2,109,333 (February 22, 1938), 2,160,962 (June 6, 1939), 2,187,306 (January 16, 1940), and 2,158,416 (May 16, 1939) describe the electrospinning process and its facilities. Other references describing the electrospinning process include Simons, US Pat. No. 3,280,229 (October 18, 1966), and Martin et al., US Pat. No. 4,044,404 (August 30, 1977), US Pat. No. 4,069,026 (January 17, 1978) to Simm et al., US Pat. No. 4,143,196 (March 6, 1979) to Simm, and US of Fine et al. Patent No. 4,223,101 (September 16, 1980), US Patent No. 4,230,650 to Guignard (October 28, 1980), US Patent No. 4,232,525 to Enjo et al (November 11, 1980) ), US Patent No. 4,287,139 (September 1, 1981) to Guignard, US Patent No. 4,323,525 (April 6, 1982) to Bonat, US Patent No. 4,552,707 (How) November 12, 1985), Bonnat, US Pat. No. 4,689,186 (August 25, 1987), and Middleton et al., US Pat. No. 4,904,272 (February 27, 1990), Setter Field et al. (Satterfield et al. U.S. Patent No. 4,968,238 (Nov. 6, 1990), Barry U.S. Patent No. 5,024,789 (January 18, 1991), Scaldino et al., U.S. Patent No. 6,106,913 (8, 2000) 22; and US Pat. No. 6,110,590 (August 29, 2000) to Zarkoob et al. These prior patents have been cited for a limited purpose to explain the general principles of the electrospinning process and facilities therefor.

Although prior references have indicated a variety of electrospinning processes and facilities for them, they extrude thin and substantially continuous starch filaments suitable for successfully processing the starch composition and forming the flexible structure 100 of the present invention. It does not suggest that it can be done. Naturally occurring starches cannot be processed by electrospinning processes because natural starches generally have a grain structure. However, it has now been found that modified and "destructurized" starch compositions can be successfully processed by using an electrospinning process.

The patent application entitled “melt processable starch composition” filed by the applicant on the same date as the filing date of the present invention discloses a starch composition suitable for the production of starch filaments for use in the flexible structure 100 of the present invention. . The starch composition comprises starch having a weight average molecular weight of about 1,000 to about 2,000,000 and may comprise a high molecular weight polymer that is substantially compatible with starch having a weight average molecular weight of at least 500,000. In one embodiment, such starch compositions have from about 20% to about 99% by weight of amylopectin.

According to the invention, the starch polymer can be mixed with water, plasticizers, and other additives, and the resulting mixture can be processed (eg extruded) and suitable starch for the flexible structure of the invention. It is configured to produce filament. Starch filaments may have a small amount of starch up to 100% starch or may be a mixture of starch and other suitable materials, such as cellulose, synthetics, proteins and any combination thereof.

Starch polymers may include naturally occurring starches, physically modified starches, chemically modified starches, and the like. Suitable naturally occurring starches are corn starch, potato starch, sweet potato starch, wheat starch, sago palm starch, tapioca starch, rice starch, soybean starch, 칡 starch, fern starch, lotus starch, waxy corn (waxy) maize), starch, high amylose corn starch, and commercial amylose flour may be included without limitation. Naturally occurring starches, especially corn starch, potato starch and wheat starch, are starch polymers selected because of their usefulness.

Physically modified starch is formed by modifying its size structure. Physically modified starches may include α-starch, fractionated starch, wet and heat treated starch, mechanically treated starch and the like.

Chemically modified starches may be formed by the reaction of alkylene oxides and other ether, ester, urethane, carbamate, or isocyanate forming materials with OH groups. Hardoxyalkyl, acetyl, or carbamate starch or mixtures thereof are examples of chemically modified starches. The degree of substitution of chemically modified starches is from 0.05 to 3.0, and more clearly from 0.05 to 0.2.

The inherent moisture content can be from about 5% to about 16% by weight, and more specifically, from about 8% to about 12%. The amylose content of starch is from about 0% to about 80%, more specifically from about 20% to about 30%.

Plasticizers may be added to the starch polymer to lower the glass transition temperature of the starch filaments made. In addition, the presence of plasticizers can lower the melt viscosity, which facilitates the melt extrusion process. Plasticizers are organic compounds having at least one hydroxyl group, for example polyols. Sorbitol, mannitol, D-glucose, polyvinyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, sugar, fructose, glycerol, and mixtures thereof have been found to be suitable. These plasticizers may be present in an amount from about 0.1% to about 70% by weight, more specifically from about 0.2% to about 30% by weight, and more specifically, from about 0.5% to about 10% by weight. Contains sorbitol, sugar, fructose.

Other additives may be included with the starch polymer, usually as a processing aid, and to change physical properties such as elasticity, dry tensile strength and wet strength of the extruded starch filaments. Additives are usually present in amounts of 0.1% to 70% by weight based on non-volatility (meaning the amount can be calculated by excluding volatiles such as moisture). Additives include, for example, urea, urea derivatives, cross-linking agents, emulsifiers, surfactants, proteins and alkali salts thereof, biodegradable synthetic polymers, beeswax, low melt synthetic thermoplastic polymers, tacky resins , Extenders, and mixtures thereof. Biodegradable synthetic polymers include polycaprolactone, polyhydroxybutyrate, polylactides, and mixtures thereof. Other additives include optical luminescent agents, antioxidants, fire protection agents, dyes, pigments, and fillers. In the present invention, additives comprising urea in an amount of from about 0.5% to about 60% by weight may be effectively included in the starch composition.

Suitable extenders for use herein are vegetable proteins such as gelatin, corn protein, sunflower protein, soy protein, cottonseed protein, and alginate, carrageenan, guar gum, agar, gum arabic and related rubber, and pectin Polysaccharides soluble in water and the like, and derivatives of cellulose soluble in water such as alkyl cellulose, hydroxyalkyl cellulose, carboxymethyl cellulose and the like. Also water soluble synthetic polymers such as polyacrylic acid, polyacrylic acid esters, polyvinyl acetate, polyvinyl alcohol, polyvinylpyrrolidone and the like can be used.

Lubricant compounds may be further added to improve the rheological properties of the starch material during the process of the present invention. The lubricant compounds may comprise animal or vegetable fats, preferably in their hardened form, especially in solid form at room temperature. Additional lubricating materials include monoglycerides, diglycerides, phosphatides, in particular lecithin. In the present invention, lubricating compounds comprising monoglycerides and glycerol monostearate are considered to be preferred.

Inorganic fillers such as oxides of magnesium, aluminum, silicon, titanium can also be added as inexpensive fillers or processing aids. In addition, inorganic salts including alkali metal salts, alkaline earth metal salts, phosphates and the like can be used as processing aids.

It is desirable that other additives depend on the particular use of the product. For example, in products such as toilet tissue, disposable towels, cosmetic tissues, and other similar products, wet strength is a desirable property. Therefore, it is desirable to add starch polymer crosslinkers, well known in the art as "wet strengthen" resins.

A general paper on the form of wet strength reinforcement resins used in papermaking technology is published in the Technical Association of the Pulp and Paper Industry (TAPPI) Special Study Series 29, Paper Wet Strength of Paper and Paper Boards. New York, 1965). The most useful wet strength reinforcing resins generally have cationic properties. Polyamide epichlorohydrin resins are cationic polyamide amine epichlorohydrin wet strength enhancing resins with special applications. Suitable types of such resins are disclosed in US Patent No. 3,700,623, filed October 24, 1972 to Keim, and US Patent No. 3,772,076, filed November 13, 1973. A commercial product of useful polyamide epicrolohydrin resins is the KymennetM mark, which is commercially available from Hercules Inc. of Wilmington, Delaware.

Glyoxylate polyacrylamides have also been found to be used as wet strength enhancing resins. Such resins are described in US Pat. No. 3,556,932, registered January 19, 1971 to Coscia et al., And US Pat. No. 3,556,933, registered January 19, 1971 to Williams et al. have. A commercial product of glyoxylate polyacrylamide resins is the ParezTM631 NC mark. The company that sold these resins is Cytec Co. of Stanford, Conn.

Another water soluble cationic resin that can be used in the present invention is urea formaldehyde and melanin formaldehyde resin. More common functional groups of such multifunctional resins are nitrogen containing groups such as amino groups and methylol groups attached to nitrogen. Polyethylenimine type resins are also useful in the present invention. In addition, temporary wet strength reinforcement resins such as Caldas 10 (manufactured by Nippon Kalit) and Cobond 1000 (manufactured by the National Starch Chemical Company) can also be used in the pathogenesis.

In the present invention, the crosslinking agent is used in amounts ranging from about 0.1% to about 10% by weight, more specifically, from about 0.1% to about 3% by weight, preferably the wet strength strengthening resin KymeneTM.

In order to produce suitable starch filaments for the flexible structure 100 of the present invention, the starch composition must exhibit any fluid action during processing such as any elongational viscosity and any number of capillaries. Of course, the type of processing (such as melt ejection, electrospinning, etc.) may require the required flow characteristics of the starch composition.

The elongation or elongation viscosity (η e) is related to the melt expansion potential of the starch composition and is particularly important for elongation processes such as starch filament production. Elongational viscosity includes three types, depending on the type of modification of the composition: monoaxial or simple extensional viscosity, biaxial extensional viscosity and pure shear viscosity. Uniaxial extensional viscosities are particularly important for uniaxial stretching processes such as mechanical extension, melt ejection, spin bonding, and electron spinning. The other two extensional viscosities are important for biaxial stretching or for processes for making films, foams, sheets or parts.

In conventional fiber spinning thermoplastics such as polyolefins, polyamides, polyesters, there is a strong correlation between the elongational viscosity and the shear viscosity of such conventional thermoplastics and mixtures thereof. This means that the radioactivity of the material can be simply determined by the melt shear viscosity, although the radioactivity is a property that is preferentially adjusted by the melt extension viscosity. This correlation is so strong that the textile industry relies on melt shear viscosity to select and formulate melt spinnable materials. Melt extension viscosity is rarely used as an industrial screening tool.

Thus, it is surprising that the starch compositions of the present invention do not necessarily show this correlation between shear viscosity and stretch viscosity. The starch composition here exhibits the typical solution flow action of the non-Newtonian flow, and thus can exhibit a strain hardening action, which means that when the stress or deformation increases, the extensional viscosity increases.

For example, when the high molecular weight polymer selected according to the present invention is added to a starch composition, the shear viscosity of the composition remains relatively unchanged or rather decreases somewhat. Such starch compositions based on the prior art are expected to exhibit reduced melt processing potential and are not expected to be suitable for melt extension processing. However, it was surprisingly found that the starch composition here showed that when a small amount of high molecular weight polymer was added, the stretch viscosity increased significantly. As a result, the starch compositions herein have been found to have enhanced melt extensibility and are suitable for melt extension processing, in particular for melt extension processing including melt blowing, textile connection, and electrospinning.

Less than about 30 Pa.s, more specifically, from about 0.1 Pa.s to about 10 Pa.s, more clearly, from about 1 to about 8 Pa.s, measured according to the test method described below. Starch compositions having a shear viscosity are useful for melt decay processing herein. Some of the starch compositions herein may have low melt viscosity, which are mixed and transported or otherwise processed in traditional polymer processing equipment commonly used for viscose fluids, such as fixed mixers equipped with metering pumps and spinnerets. The shear viscosity of such starch compositions can be effectively modified by the molecular weight and molecular weight distribution of the starch, by the molecular weight of the high molecular weight polymer, and by the amount of plasticizer and / or solvent used. Reducing the average molecular weight of starch is an effective way to lower the shear viscosity of the composition.

In one embodiment of the invention, the melt processible starch composition is preferably at a temperature of from about 50 Pa.s to about 20,000 Pa.s, in particular from about 100 Pa.s to 15,000 Pa.s. From 200 Pa.s to 10,000 Pa.s, more preferably from about 300 Pa.s to about 5,000 Pa.s, most preferably from about 500 Pa.s to about 3,500 Pa.s. Have elongation viscosity. This elongational viscosity is calculated according to the method described in the Analytical Methods section below.

Many factors can affect the flow behavior (including elongational viscosity) of the starch composition. These factors include the type and amount of polymerization components used, the molecular weight and molecular weight distribution of the components, including starches and high molecular weight polymers, the type and amount of additives (such as plasticizers, diluents, processing aids), and the type of processing (melting). Eruption or electron emission) and temperature, pressure, strain rate and relative humidity, and, in the case of non-Newtonian materials, include, without limitation, processing conditions such as the strength of deformation (ie, time or strain strength dependence). Some materials can be strain cured, ie their extensional viscosity increases as the strain increases. This is believed to be due to the expansion of the entangled polymer network. If the pressure is removed from the material, the expanded entangled polymer network relaxes for lower strain and depends on the relaxation time constant which is a function of temperature, polymer molecular weight, solvent or plasticizer concentration and other factors.

The presence and nature of the high molecular weight polymer can have a great effect on the elongational viscosity of the starch composition. High molecular weight polymers that can be used to enhance the melt extension of the starch compositions used in the present invention are usually high molecular weight, substantially linear polymers. Moreover, high molecular weight polymers that are substantially compatible with starch are most effective in enhancing the melt elongation of the starch composition.

Starch compositions useful for melt extension processing usually have their elongational viscosity increased by a coefficient of at least 10 when a selected high molecular weight polymer is added to the composition. Usually, the starch composition according to the present invention shows an increase in the elongational viscosity of the coefficient from about 10 to about 500, more precisely 20 to 300, more precisely 30 to 100. The higher the level of the high molecular weight polymer, the greater the increase in extensional viscosity. High molecular weight polymers can be added to adjust the elongation viscosity to a value from 200 to 2000 in a Hencky strain of 6. For example, polyacrylamides having molecular weights of up to one million or fifteen million at levels from 0.001% to 0.1% may be added to make up the starch composition.

The type and level of starch used also influences the elongational viscosity of the starch composition. In general, as the amylose component of starch decreases, the elongational viscosity increases. Also generally as the starch molecular weight increases within this range, the elongational viscosity increases. As a result, in general, as the starch level in the composition increases, the elongational viscosity increases. (Inversely, as the level of additives in the composition increases, the elongational viscosity decreases.)

The temperature of the starch composition can greatly affect the elongational viscosity of the starch composition. For the purposes of the present invention, all conventional means of controlling the temperature of the starch composition can be used if suitable for the particular processing used. For example, in embodiments where starch filaments are produced by extrusion through a die, the die temperature can have a significant impact on the elongational viscosity of the extruded starch composition. Usually, as the temperature of the starch composition rises, the elongational viscosity of the starch composition decreases. The temperature of the starch composition may be measured from about 20 ° C. to about 180 ° C., precisely from about 20 ° C. to about 90 ° C., and more precisely from about 50 ° C. to about 80 ° C. It is believed that the presence or absence of a solid in the starch composition can affect the required temperature.

Trouton ratio (Tr) can be used to express the renal flow action. The trauton ratio is defined as the ratio between the elongational viscosity (η _e ) and the shear viscosity (η _s ).

Tr = η _e (ε˙, t) / η _s ,

Here, the elongation viscosity η _e depends on the strain ratio ε˙ and the time t. For Newtonian fluids, the uniaxial stretched Truton ratio has a constant value of three. In non-Newtonian fluids such as the starch compositions herein, the elongational viscosity depends on the strain rate (ε˙) and time (t). In addition, melt processable compositions according to the invention usually have a toluton ratio of at least about 3. Normally, the tonnage ratio is from about 10 to about 5,000, more precisely from about 20 to about 1,000, more precisely from about 30 to about when measured at an elongation rate of 700 s ⁻¹ and a processing temperature at a Henkie strain of 6 It is measured up to 500.

Also in embodiments where the starch composition is produced by extrusion molding, the capillary number (Ca) of the starch composition is important to the melt processing potential as it passes through the extrusion die. Capillary numbers are numbers representing the ratio of viscous flow forces to surface tension. Near the outlet of the capillary die, if the viscous force is not much greater than the surface tension, the flowable fiber turns into droplets, commonly referred to as "atomization". Capillary numbers are calculated according to the following equation.

_{Ca = (η s · Q)} / (π · r 2 · σ)

Where ηs is the shear conduction in Pa · s measured at a shear rate of 3000 s ^-1 , Q is the flow rate of fluid flow in the capacitive die through the capillary die in m ³ / s, and r is the Radius, and σ is the fluid surface tension in Newtons per meter.

Since capillary numbers are related to shear viscosity as described above, they are affected by the same factors affecting shear viscosity and in a similar manner. As used herein, the term "inherent" in terms of capillary number or surface tension refers to the properties of the starch composition that are not affected by external factors, such as the presence of electrical regions. The term "effective" refers to the properties of the starch composition affected by external factors such as the electrical domain.

In an embodiment according to the invention, the melt processible starch compositions have a unique number of capillaries when they pass through a die of at least 0.01 and an effective capillary number of at least 1.0. In the absence of static electricity, this capillary number should be greater than 1 for stability and preferably greater than 5 for strong stability of the formed fibers. In the presence of static electricity, the charge repulsion action interferes with the effect of surface tension, and the inherent capillary number measured without electric charge may be less than one. When dislocations are applied to the fiber, the effective surface tension is reduced and the effective capillary number is increased based on the following equation. Although capillary numbers can be expressed in various forms, representative equations that can be used to define the intrinsic capillary number of a material are as follows.

Ca inherent = η _s v / σ,

Where Ca inherent is the unique capillary number,

η s is the shear viscosity of the fluid,

v is the linear viscosity of the fluid,

σ is the surface tension of the fluid.

If this relates to the present invention, a representative sample has the following compositions and properties.

Furtherance

National Starch Purity Gum 59 40.00%

Deionized Water 59.99%

Seetec's superfloc N-300 LMW 0.01%

(High molecular weight polyacrylamide)

120 ° F operating temperature

Shear viscosity 0.1 Pa · s at 3000S ^-1

Nozzle Diameter .0254 cm

Linear velocity .236 m / sec

Original surface tension 72dynes / cm

In experiments without electrostatic charging of the fluid, the material will flow through the nozzle tip and create droplets that will drop into gravity. As the potential of the system is increased, the droplets become smaller in size and begin to accelerate towards the grounding mechanism. When the potential (25 kilovolts in this example) has reached the threshold, droplets no longer form at the tip of the nozzle, and small continuous fibers are ejected from the tip of the nozzle. Thus, the applied potential now surpasses the surface tension to eliminate the capillary failure mode. Valid capillary numbers are now greater than one. Continuous fibers were prepared in a laboratory equipped with the solution and the experimental equipment installed. These fibers were collected on a vacuum screen in the form of a fiber mat. In the analysis through the use of an optical microscope, a fiber with a diameter of 3 to 5 microns was observed.

In some embodiments, the intrinsic capillary number may be at least 1, more precisely, from 1 to 100, more preferably from about 3 to 50, more preferably from about 5 to about 30.

The starch composition herein is usually processed in a fluid state that occurs at a temperature at least equal to or greater than the "melting temperature". The processing temperature range is thus controlled by the “melting point” of the starch composition measured according to the test methods described in detail herein. The melting point of the starch composition ranges from about 20 ° C. to about 180 ° C., in particular from about 30 ° C. to about 130 ° C., more preferably from 50 ° C. to 90 ° C. The melting point of the starch composition is related to the amylose content (higher amylose content requires higher temperatures), moisture content, plasticizer content, and plasticizer form of the starch.

Exemplary uniaxial stretching processes suitable for starch compositions include melt spinning, melt blowing, and spin bonding. This process is described in US Patent No. 4,064,605, filed December 27, 1977 to Akiyama et al., And US Patent No. 4,418,026, Bowe, registered November 29, 1983 to Blackie et al. U.S. Patent No. 4,855,179, filed August 8, 1989 to Bourland et al., U.S. Patent No. 4,909,976, March 20, 1990 to Cuculo et al. U.S. Patent No. 5,145,631, filed Sep. 8, 1992, by Buehler et al., US Patent No. 5,516,815, filed May 14, 1996, by August 30, 1994, Rhim et al. It is described in detail in one registered US Pat. No. 5,342,335.

Shown schematically in FIGS. 7, 8, and 9 is an apparatus 10 for producing starch components suitable for the flexible structure of the present invention. The device 10 is known in the art to include, for example, a single screw or double screw extruder, a positive displacement pump or a combination thereof. The starch composition may have a total moisture content, ranging from about 5% to about 80%, more precisely from about 10% to about 60%, based on the total weight of the starch material, plus the water of hydration and the added water. Can be. The starch material is heated to a sufficiently high temperature to form a pseudo thermoplastic melt. This temperature is usually higher than the glass transition temperature and / or melting temperature of the formed material. Similar thermoplastic melts of the present invention, as is well known in the art, are synthetic fluids having shear ratios which depend on viscosity. The viscosity decreases with increasing shear rate as well as with increasing temperature.

The starch material may be heated to a closed volume when there is a low concentration of water to convert the starch material into a similar thermoplastic melt. The closed volume may be a closed container or a volume produced by the sealing operation of the feeding material as occurs in the screw of the extrusion. The pressure generated in the closed vessel will include the pressure due to the water vapor pressure of the water, as well as the pressure generated due to the compression of the material in the screw-barrel of the extruder.

Chain scission catalysts that reduce molecular weight by dividing glycoside bonds into starch large molecules, resulting in a decrease in the average molecular weight of starch, can be used to reduce the viscosity of similar thermoplastic melts. Suitable catalysts include inorganic acids and organic acids. Suitable inorganic acids include hydrochloric acid, sulfur phase, nitric acid, phosphoric acid, boric acid, and the like, like partial salts of polybasic acids such as NaHSO ₄ or NaH ₂ PO ₄ and the like. Suitable organic acids include other organic acids already known in the art, including formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, oxalic acid, citric acid, tartaric acid, itaconic acid, succinic acid, and partial salts of polybasic acids. Hydrochloric acid, sulfuric acid, citric acid and mixtures thereof can be effectively used in the present invention.

The molecular weight reduction of the unmodified starch used may be by a coefficient from 2 to 5000, more precisely from 4 to 4000. The concentration of the catalyst is in the range from 10 ⁻⁶ to 10 ⁻² moles of catalyst per mole of anhydrous glucose, more precisely between 0.1 × 10 ⁻³ to 5 × 10 ₋₃ moles of catalyst per mole of anhydrous glucose of starch. .

In FIG. 7, the starch composition is fed to an apparatus 10 for electrospinning production of starch filaments used to make the flexible structure 100 of the present invention. The device 10 has a starch composition 17 therein so as to receive the starch composition 17, which is extruded into the starch filament 17a (arrow D) through the jet 14 of the die head 13. (Arrow A) It consists of a structured and shaped housing 11. Annular pupil 12 may be provided to purify the heating fluid (arrows B and C) that heat the starch composition to the desired temperature. Other heating means already known in the art, such as methods using electronic heating, pulsed combustion, moisture vapor heating, and the like, can also be used to heat the starch composition.

The electrical zone can be applied directly to the housing 11 and / or the extrusion die 13 via a starch solution, for example via an electrically filled probe. If necessary, the molding member 200 may be electrically charged with a charge opposite to that of the extruded starch filament. In addition, the molding member may be grounded. The electrical difference can be from 5kV to 60kV, more specifically from 20kV to 40kV.

The plurality of extruded starch filaments may be placed in a molding member 200 running in the machine direction (MD) at a distance from the device 10. This distance should be far enough to allow the starch filament to extend, dry, and at the same time maintain a differential charge between the starch filament and the molding member 200 exiting the jet nozzle 14. For this purpose, the outflow of dry air can be applied to the starch filament so that the starch filament can run at an angle. This allows to maintain a minimum distance between them for the purpose of maintaining differential charges between the jet nozzle 14 and the molding member 200 and at the same time between the nozzle and the molding member 200 for the purpose of effectively drying the fibers. To maximize the length of some of the fibers. In this arrangement, the molding member 200 may be placed at an angle with respect to the direction of the fiber when the fiber exits the jet nozzle 14 (arrow D in FIG. 7).

Optionally, dampening air can be used with the electrical force to provide stretching force to taper or stretch the starch filament before the starch filament is placed on the molding member 200. FIG. 7A shows one annular bore 15 surrounding the jet nozzle 14 with three different holes 16 evenly spaced around the jet nozzle 14 for damping air. An exemplary embodiment of a die head is schematically shown. Of course, other arrangements of attenuated air may be used in the present invention, as is known in the art.

According to the present invention, the starch filament may have a size measured from about 0.01 dtex to about 135 dtex, in particular from about 0.02 dtex to about 30 dtex, more preferably from about 0.02 dtex to about 5 dtex. Starch filaments can have a variety of cross-sections, including but not limited to round, oval, rectangular, triangular, hexagonal, cross-shaped, star-shaped, irregular, and any combination thereof. Those skilled in the art will appreciate that this variety of forms may be formed by other forms of die nozzles used to produce starch filaments.

10A shows without limitation the possible cross-sectional area of the starch filament. The cross-sectional area of the starch filament is an area perpendicular to the main axis of the starch filament and is outlined by a boundary line (peripheral) formed by the outer surface of the starch filament in the cross-sectional plane. It is recognized that as the surface area of the starch filament (per unit of length or its weight) increases, the opacity of the flexible structure 100 comprising the starch filament increases. Thus, maximizing the surface area of the starch filament as the even diameter of the starch filament increases may be beneficial to increase the opacity of the resulting flexible structure 100 of the present invention. One way to increase the uniform diameter of starch filaments is to make starch filaments that have a cross-sectional shape of a multi-layered surface that is not circular.

In addition, the starch filaments need not have a uniform thickness and / or cross-sectional area through all or part of the length of the fiber. For example, FIG. 10 schematically shows a fragment of starch filament having different cross-sectional areas along its length. This other cross-sectional area can be varied, for example, by varying the pressure inside the die, or by changing one of the properties (such as velocity, direction) of attenuated air or dry air in melt blowing or a combination of melt blowing and electrospinning. Is formed.

Some starch filaments may have "notches" injected at certain intervals along the length or portion of the fiber. This variation of the cross-sectional area of the starch filament along the fiber length promotes the fluidity of the fibers, improves the ability of the fibers to intertwine in the resulting flexible structure 100, and the resulting softness of the flexible structure 100 It is believed to have a positive effect on liquidity. Other effective irregularities in notches or starch filaments can be formed by contacting the starch filaments with a surface having sharp edges or protrusions, as described below.

The next step in the processing is to provide the molding member 200. Molding member 200 includes a patterned cylinder (not shown), or a member that forms another pattern, such as a belt or band. The molding member 200 is composed of a fiber contact surface 201 and a rear surface 202 facing the fiber contact surface 201. Differential fluid pressures (eg, vacuum pressures that may be present under the belt or inside the drum) may form starch filaments according to the pattern of the molding member to form distinct areas within the flexible structure that is made.

In the process of making the structure 100 of the present invention, the starch filament is placed on the fiber contact surface 201. Secondary surface 202 is usually in contact with facilities such as support rollers, guide rollers, vacuum devices, etc., which are necessary for a particular machining. The fiber contact surface 201 includes a three-dimensional pattern of protrusions and / or depressions. Usually (but not necessarily), these patterns are not random but repetitive. The three-dimensional pattern of the fiber contact surface 201 may comprise a substantially continuous pattern (FIG. 4), a substantially continuous pattern (FIG. 5), a pattern comprising a plurality of discrete protrusions (FIG. 5), or some combination thereof. It may include. When a plurality of starch filaments are placed on the fiber contact surface 201 of the molding member 200, the plurality of flowable starch filaments at least partially follow the molding pattern of the molding member 200.

The molding member 200 includes a belt or band that is macroscopically single plane when it is placed in the reference X-Y plane, where the Z direction is perpendicular to the X-Y plane. Similarly, flexible structure 100 can be thought of as a macroscopic single plane that lies in a plane parallel to the X-Y plane. The Z direction perpendicular to the X-Y plane is the direction in which the side diameter or thickness of the flexible structure 100 extends, or the height of the distinct regions of the molding member 200 or the flexible structure 100 extends.

If necessary, the molding member 200 including the belt may be implemented with a compression belt. Compression belts suitable for use in accordance with the present invention are described in US Pat. No. 5,549,790, issued August 27, 1996 to Phan, US Patent No. 5,556,509, registered September 17, 1996 to Trokhan et al. , US Patent No. 5,580,423, filed December 3, 1996 to Ampulski et al., US Pat. No. 5,609,725, March 11, 1997, Trokhan et al. US Patent No. 5,629,052, registered on May 13, 1997, Ampulski et al., US Patent No. 5,693,187, issued December 2, 1997, to Trokhan et al. July 7, 1998, US Patent No. 5,709,775, Ampulski et al., Registered January 20, 1998, August 18, 1998, US Patent No. 5,776,307, Ampulski et al. United States Patent No. 5,795,440, phan, September 29, 1998 Registered US Patent No. 5,814,190, Trokhan et al. US Patent No. 5,817,377, Ampulski et al., Registered on December 6, 1998, US Patent No. 5,846,379, registered on January 5, 1999, Ampulski et al. US Patent No. 5,855,739, and US Patent No. 5,861,082, registered January 19, 1999 to Ampulski et al., And the like. In another embodiment, the molding member 200 may be implemented as a compression belt in accordance with the disclosure of US Patent No. 5,569,358, filed October 29, 1996 by Cameron.

The principle embodiment of the molding member 200 consists of a resinous tissue 210 that is bonded to the reinforcing device 250. The resinous tissue 210 may have a particular preselected pattern. For example, FIG. 4 shows a substantially continuous structure 210 having substantially a plurality of holes 220. In some embodiments, the reinforcement device 250 may be substantially fluid permeable. Fluid permeation enhancement device 250 may comprise a woven screen, or perforated component, felt, or any combination thereof. Portions of the reinforcement device 250 fitted with the holes 220 in the molding member 200 prevent starch filaments from passing through the molding member 200 and the generation of pinholes in the resulting flexible structure 100. Reduce If you do not want to use a woven fabric in the reinforcement device, a nonwoven component, screen, net, press felt or plate or film with multiple holes may provide adequate support and strength for the structure 210. Suitable reinforcing device 250 is described in US patent no. 5,496,624, filed March 5, 1996 to Stetelljes et al., US patent registered March 19, 1996 to Trokhan et al. No. 5,500,277, and US Pat. No. 5,566,724, filed Oct. 22, 1996, to Trokhan et al. Various forms of fluid permeation enhancement device 250 are described in US Pat. Nos. 5,275,700 and 5,954,097. The reinforcement device 250 may comprise a felt, which may be a "press felt" used in traditional paper making. The structure 210 can be applied to the reinforcement device 250, which is US Patent No. 5,549,790, registered August 27, 1996, US Patent No. 5,556,509, registered September 17, 1996, December 3, 1996. U.S. Patent 5,580,423, U.S. Patent 5,609,725, filed Mar. 11, 1997, U.S. Patent 5,629,052, filed May 13, 1997, U.S. Patent 5,637,194, filed June 10, 1997, U.S. Patent 5,674,663, US Patent 5,693,187, filed December 2, 1997, US Patent 5,709,775, registered January 20, 1998, US Patent 5,795,440, registered August 18, 1998, 5,846,379 December 8, 1998.

In addition, the reinforcement device 250 may be fluid impermeable. Impermeable reinforcement device 250 is the same or different from the material, plastic material, metal, other suitable natural or synthetic material, or any combination thereof used to make structure 210 of molding member 200 of the present invention. It may include a polymeric resin material. The fluid impermeable strengthening apparatus 250 will make the molding member 200 impermeable as a whole. The reinforcement device 250 may be partially fluid permeable and partially fluid impermeable. This means that some parts of the reinforcement device 250 may be fluid permeable, while other parts of the reinforcement device 250 may be fluid impermeable. The molding member 200 may be fluid permeable, fluid impermeable, or partially fluid permeable, as a whole. In partly fluid permeable molding member 200, only the macroscopic region, or portion, or portions of the regions of molding member 200 is fluid permeable.

If necessary, a reinforcement device 250 including a Jacquard weave can be used. Exemplary belts with jacquard weave are disclosed in U.S. Patent 5,429,686, filed Jul. 4, 1995, U.S. Patent 5,672,248, filed September 30, 1997, U.S. Patent 5,746,887, January 25, 2000 In the registered US Patent 6,017,417, these references are cited for the purpose of demonstrating the principle construction of recard weaving. The present invention includes a molding member 200 comprising a fiber contact surface 201 having a jacquard weave pattern. The jacquard woven pattern may be used as the forming member 500, the molding member 200, the pressing surface, or the like. Jacquard weaving is particularly useful if you do not want the structure to be pressed or squeezed into pieces, as is usually caused by transferring to a Yankee drying drum.

According to the present invention, one, several or all of the holes 200 of the molding member 200 may be "hidden" or "closed", as described in US Patent 5,972,813, filed October 26, 1999. . As described in the cited patents above, polyurethane foams, elastomers, silicones can be used to make the holes 220 fluid impermeable.

The embodiment of the molding member 200 shown in FIG. 6 includes a plurality of floating portions 219 extended (usually laterally) to a plurality of base portions 211. Floating portion 219 is a reinforcing device 250 to form a void 215 into which the starch filaments of the present invention can be deflected to form cantilever portion 129, as described above in connection with FIG. Rises from The molding member 200 including the floating portion 219 may comprise a multilayer structure formed by at least two layers 211 and 212 connected together in the form of facing each other (FIG. 6). Each layer may have a structure similar to one of several of the above patents incorporated by reference. Each layer 211, 212 may have at least one hole 220 (FIG. 4, FIG. 4A) extending between the bottom surface and the top surface. The joined layers are laid in such a way that one hole of one layer overlaps (in a direction perpendicular to the general plane of the molding member 200) together with the tissue portion of the other layer, and this portion is the floating portion 219 above. ).

Another embodiment of a molding member comprising a plurality of floating portions can be made by differential curing of the photosensitive resin layer, or by another curable material, through a mask comprising transparent and opaque regions. . Opaque areas include areas with differential opacity, such as areas with relatively high opacity (opaque like black) and areas with relatively low partial opacity (ie, some transparency).

When a curable layer having a secondary side facing the filament receiving side is exposed to curing radiation through a mask adjacent to the filament receiving side of the coating, the opaque areas of the mask cure the primary region of the coating through the entire thickness of the coating. The primary area of the coating is protected from hardening radiation to prevent it. The partially opaque regions of the mask only partially surround the secondary region of the coating so that the curing radiation (starting from the filament receiving side of the coating toward its secondary side) cures the secondary region to a predetermined thickness thinner than the thickness of the coating. have. Transparent areas of the mask leave uncovered tertiary areas in order to allow cured radiation to cure the tertiary areas through the entire thickness of the coating.

As a result, the uncured material can be removed from the partially formed molding member. The resulting hardened tissue has a fiber contact side 201 formed from the filament receiving side of the coating and a back side 202 formed from the secondary side of the coating. The resulting tissue includes a back side 202 and has a plurality of bases 211 formed from the tertiary region of the coating and a plurality of floating portions 219 comprising the filament receiving side 201 and formed from the secondary region of the coating. . The plurality of bases may comprise a substantially continuous pattern, a substantially continuous pattern, a discontinuous pattern, or some combination thereof, as described above. Floating portion 219 extends obliquely from a plurality of bases (usually, but not necessarily, 90 °) and from the back surface 202 of the tissue created to form an empty space between the floating portion and the back surface 202. Apart Usually, when a molding member 200 comprising a reinforcing device 250 is used, an empty space 215 is formed between the floating portion 219 and the reinforcing device 250, as shown in FIG. 6.

The next step is to place pseudo thermoplastic starch filaments on the fiber contact surface 201 of the molding member 200, as schematically shown in FIGS. 7 to 9, and to place the plurality of starch filaments of the molding member 200. Forming at least partially as a three-dimensional pattern. In the embodiment shown schematically in FIG. 7, upon exiting the stretching device, the starch filament 17b is placed on the three-dimensional fiber contact surface 201 of the molding member 200. In an industrially continuing process, the molding member 200 includes a circulation belt that runs continuously in the machine direction MD, as shown in FIGS. U.S. Patent 5,688,468, registered November 18, 1997, discloses a process and apparatus for producing non-woven landings consisting of fibers of reduced diameter.

In some embodiments, multiple fibers may be placed in forming member 500, as shown in FIG. 9, rather than molding member 200 primarily. This step is optional and can be used to improve the uniformity of the basis weight of the multiple starch filaments throughout the width of the structure 10 made. Forming member 500 comprising a wire is contemplated in the present invention. In the exemplary embodiment of FIG. 9, the forming member 500 travels in the machine direction relative to the rolls 500a and 500b. The forming member is fluid permeable, and the vacuum device 550 is positioned below the forming member to apply differential hydraulic pressure to the plurality of starch filaments to promote more or less even distribution of the starch filaments through the receiving surface of the forming member 500.

If desired, forming member 500 may be used to form various irregularities of starch filaments, particularly of fiber surfaces. For example, the fiber-receiving surface of the forming member is notch of the starch filament that can be effective to drive off the relatively soft starch filament and to the finished flexible structure 100 as described above (schematically in FIG. 11). Or various shapes of edges (not shown) configured to generate other irregularities.

In the embodiment of FIG. 9, a plurality of fibers are applied by conventionally known means, such as applying a vacuum pressure sufficient to separate and attach the plurality of starch filaments placed on the forming member 500 to the molding member 200. By the vacuum shoe 600, it may be transferred from the forming member 500 to the molding member 200.

In a continuous process of making the flexible structure 100, the molding member 200 may have a lower linear velocity than the forming member 500. The use of this differential velocity at the point of delivery is generally known in papermaking technology and can be used for so-called microcontraction, which is usually effective when applied to low density woven landings. U.S. Patent 4,440,597 is cited to explain the principle mechanism of microshrinkage, and details "wet-microcontration". Briefly wet microshrinkage involves transitioning from a primary member (such as a porous member) to a fabric having a low fiber density from a secondary member (such as an open weave structure) to move more slowly than the primary member. If starch filaments can be formed, the number of starch filaments are sufficiently fluidized by the time of travel from a relatively slow moving support (such as forming member 500) to a relatively fast moving support (such as molding member 200). If it can be maintained, it is believed that it is possible to effectively deflate a plurality of starch filaments, and to shorten the made flexible structure 100. The speed of the molding member 200 may be about 1% to about 25% faster than the forming member 500.

9A shows an embodiment of processing according to the present invention, wherein the starch filament is angled to the molding member 200 at an angle A, which may be from about 1 ° to about 89 °, more specifically from about 5 ° to 85 °. Can be placed. This embodiment is particularly effective when molding member 200 having floating portion 219 is used. This laying of the starch filament 17a at an angle to the molding member 200 creates an empty space between the reinforcing device 250 and the floating portion 219 to make it easier to obtain a long, fluid starch filament 17a. The starch filament is promoted to more easily fill the empty space 215. In FIG. 9A, the starch filament 17a is placed in the molding member 200 in two stages, so that two kinds of voids 219-upstream voids 215a and downstream voids 215b-are laid at an angle. To the molding member 200. The downstream angle A, which depends on the specific geometry of the molding member 200, in particular on the geometry and / or orientation of the floating portion 219, may be equal to or different from the upstream angle B.

As soon as a plurality of starch filaments are placed on the fiber contact surface 201, the plurality of fibers at least partially follow a three-dimensional pattern. In addition, various means are used to form the starch filaments in a three-dimensional pattern of the molding member 200. One method involves applying differential hydraulic pressure to a plurality of starch filaments. This method may be particularly effective when the molding member 200 is fluid permeable. For example, the vacuum device 550 placed on the back surface 202 of the fluid permeable molding member 200 may be arranged to apply vacuum pressure to the molding member 200 and to a plurality of starch filaments placed thereon. have. Under the influence of vacuum pressure, certain starch filaments may be deflected into the cavity 220 and / or the void 215 of the molding member 200, or may be formed along its three-dimensional pattern.

Three regions of the flexible structure 100 may generally have an equivalent basis weight. As a portion of the starch filament is deflected into the hole 220, one region can lower the density of the pillow 120 produced in relation to the density of the primarily pressed region 110. The region 110 that is not deflected into the hole 220 can be pressed by compressing the fluid structure in the compression nip. If pressed, the density of the pressed region is increased in relation to the density of the pillow 120 and the density of the tertiary region 130. The density of the region 110 and the tertiary region 130, which are not deflected into the holes 220, are higher than the pillow 120. The tertiary region 130 will similarly have a density that is halfway between the densities of the pressed region 110 and the pillow 120.

In FIG. 1A, the flowable structure 100 according to the present invention can be considered to have three different densities. The highest density region is the high density pressed region 110. The pressed region 110 corresponds in position and geometry to the tissue 210 of the molding member 200. The lowest density region of the flexible structure 100 becomes the pillow 120 region, which corresponds in position and geometry to the holes 220 of the molding member 200. The tertiary region 130 corresponding to the fragrance 230 of the molding member 200 has a density that is halfway between the density of the pillow 120 and the pressed region 110. "Scentlines 230" is the surface of tissue 210 having a Z-direction vector component extending from the filament receiving side 201 of molding member 200 toward its rear side 202. The fragrance 230 does not extend completely through the tissue 210 like the hole 220. Thus, the difference between fragrance 230 and hole 220 is that hole 220 presents a through hole in tissue 210, while fragrance 230 is a hole, gold, deep gap or It represents a notch.

Three regions of the structure 100 according to the invention are laid at three different heights. The height of the area refers to the distance from the reference plane (ie, the X-Y plane). For convenience, the reference plane can be visualized horizontally, where the height distance from the reference plane is vertical. The height of a particular area of the starch filament structure 100 can be measured using a general purpose non-contact measuring device known in the art. Particularly bonded measuring instruments include a non-contact laser replacement sensor having a beam size of 0.3 x 1.2 millimeters in the range of 50 millimeters. Suitable non-contact laser replacement sensors are sold in the MX1A / B model by Edec Company. In addition, prior art contact shape gauges can also be used to measure differential heights. Gauges of this type are described in US Pat. No. 4,300,981. The structure 100 according to the present invention is located in the reference plane with the pressed region 110 in contact with the reference plane. Pillow 120 and tertiary region 130 extend vertically from the reference plane. Differential heights of regions 110, 120, 130 may also be formed by using molding member 200 having a three-dimensional pattern of differential depth or height, as shown in FIG. 5A. Such three-dimensional patterns with differential depth / height can be made by wearing preselected portions of the molding member 200 to reduce their height. In addition, the molding member 200 including the cured material may be made by using a three-dimensional mask. By using a three-dimensional mask that includes differential depths / heights of depressions / projections, it is also possible to form corresponding tissue 210 having differential heights. Other conventional techniques for making a surface of differential height can also be used for this purpose.

To enhance the possible sound effect of the sudden application of differential hydraulic pressure by the vacuum device 550 (FIGS. 8 and 9) or the vacuum pick-up shoe 600, FIG. ), So-called pinholes may be formed in the resulting flexible structure, and the back surface of the molding member may be "textured" to create fine surface irregularities. Such surface irregularities may be effective in some embodiments of the molding member 200, because they are located between the rear surface 202 of the molding member 200 and the surface of the paper making equipment (eg, the surface of the vacuum apparatus). This impedes the formation of a vacuum seal, thereby causing a "leakage" between them and reducing the undesirable consequences of applying vacuum pressure in the through air drying process making the flexible structure 100 of the present invention. Other methods of causing such leaks are disclosed in US Pat. Nos. 5,718,806, 5,741,402, 5,744,007, 5,776,311, and 5,885,421.

Such leakage can also occur using the so-called "differential light transmission technology", which is disclosed in US Pat. Nos. 5,624,790, 5,554,467, 5,529,664, 5,514,523, and 5,334,289. The molding member can be made by coating the photosensitive resin on a reinforcement device having an opaque portion and exposing the coating to active wavelengths of light through a mask having transparent and opaque regions and through the reinforcement device. Another way to create background surface irregularities involves the use of a woven forming surface or a woven barrier film, which is described in US Pat. Nos. 5,364,504,5,260,171, and 5,098,522. The molding member can be made by injecting a photosensitive resin into the reinforcement device while the reinforcement device is running over the woven surface, and by exposing the coating to light of dynamic wavelengths through a mask having transparent and opaque regions.

Means such as vacuum apparatus 550 for applying a vacuum (i.e., lower than atmospheric pressure) pressure to the plurality of fibers through the fluid permeable molding member 200 or a fan (not shown) for applying a positive pressure to the plurality of fibers It can be used to easily deflect the fibers of the into a three-dimensional pattern of the molding member.

Figure 9 also schematically illustrates an optional step of processing according to the present invention, wherein the plurality of starch filaments comprise a circulation band running around rolls 800a and 800b and in contact with the plurality of fibers. Overlaid with 800. This means that a number of fibers are sandwiched between the molding member 200 and the flowable sheet material 800 at regular time intervals. The flowable sheet material 800 has lower air permeability than the sheet of the molding member 200, and in some embodiments is air impermeable. Applying differential hydraulic pressure P to the flow sheet 800 causes at least a partial deflection of the flow sheet towards the three-dimensional pattern of the molding member 200, such that a plurality of starch filaments are in close proximity to the three-dimensional pattern of the molding member 200. Forced to form. U. S. Patent 5,893, 965 describes the principle placement of processing and equipment using flow sheet materials.

In addition to differential hydraulic pressure, mechanical pressure may also be used for the formation of three-dimensional fine patterns of the flexible structure 100 according to the present invention. Such mechanical pressure may be generated by a suitable pressing surface constituting the surface of the roller, the surface of the band or the like. 8 shows two embodiments of a pressing surface. A pair or several press rolls 900a, 900b, 900c, 900d may be used to place the starch filament on the molding member 200 to sufficiently follow the three-dimensional pattern of the molding member. The pressure exerted by the pressure rolls can be staged, and if desired, the pressure generated between the rolls 900c, 900d can be greater than that generated between the other rolls 900a, 900b. In addition, the circulation pressing band 950 traveling around the rolls 950a and 950b may be pressed against a part of the fiber side 201 of the molding member 200 so that the flexible structure 100 therebetween is pressed.

The pressing surface can be smooth or have its own three-dimensional pattern. In the latter example, the pressing surface, together with or independently of the three-dimensional pattern of the molding member 200, may be used as an embossing device to form a distinct micro pattern of protrusions and / or depressions in the flexible structure 100. have. In addition, these pressing surfaces can be used to introduce various additives such as softeners and inks into the flexible structure 100 made. Traditional techniques, such as ink roll 910 or spray apparatus (shower 920), can be used to directly or indirectly add various additives to the flexible structure 100 made.

The structure 100 can be selectively shrunk as in the prior art. Shrinkage can be achieved by creping the structure 100 from a hard surface, more specifically from the cylinder 290 shown in FIG. 9. Creping is done by a doctor blade 292 as is well known. Creping can be done as described in US Pat. No. 4,919,756. Shrinkage is through microshrinkage, as described above.

The retracted fluid structure 100 usually has a greater stretching force in the machine direction than in the cross machine direction and can be bent around the hinge line formed by the shrinking process, which hinge line is generally in the cross machine direction, ie, the flexible structure. It extends along the width of 100. Non-creped or non-shrink flexible structures 100 are also included within the scope of the present invention.

Various products can be made using the flexible structure 100 of the present invention. These products include air, oil, water filters, vacuum cleaner filters, air filters, face masks, coffee or tea filters, thermal barrier materials and sound barrier materials, sanitary products such as disposable ear muffs and feminine sanitary napkins, fine fibers or breathable fibers. Reinforced tissues and toilet paper for high-strength paper such as woven fibers that can be broken down into microorganisms with improved absorbency and softness, electrostatically charged woven skins for collecting and removing dust, wrapping paper, stationery, newspapers, and paperboards, Tissues such as paper towels, napkins, cosmetic tissues, surgical curtains, bandages, band-aids, eye bags, medical supplies such as self-dissolving sutures, and dental supplies such as dental cotton and brush heads. The flexible structure 100 may also be used for special purposes, including deodorants, termite repellents, pests, and the like. Since the product of the present invention absorbs water and oil, it can be used for cleaning up spilled water or oil, or for containing and distilling water adjusted for agricultural or horticultural applications. The resulting flexible structures or textile fabrics can also be applied with other materials such as sawdust, wood pulp, plastics, concrete, which are walls, support beams, pressure boards, drywall and backrests, ceiling tiles, plaster frames, splint It can be used to make medical supplies such as tongue sticks, and fireplace logs for decorative purposes.

Test Methods

A. Shear Viscosity

The shear viscosity of the composition is measured by a capillary viscometer (Geottert Co., Model Leograph 2003). The measurement is made using a capillary die of diameter D 1.0 mm and length L 30 mm (ie L / D = 30). The die is attached to the bottom of the barrel and the test temperature is fixed at 25 to 90 ° C. The preheated sample composition is placed in the barrel portion of the viscometer to fill the barrel (approximately 60 g of sample is used). The barrel temperature is fixed to a specific test temperature. In general, since air can form bubbles on the surface and cause problems in operation, compression can be performed to remove the air before the test operation. A piston is programmed to push the sample from the barrel into the die in the die at a constant speed. At this time, the pressure of the sample is lowered. The apparent viscosity of the composition can be obtained from the pressure drop and the flow rate of the sample through the hole. The log (apparent viscosity) is then plotted against log (shear viscosity) and the plot is applied to the law of force η = Kγn-1. Where K is the material constant and γ is the shear rate. The shear viscosity of the starch composition is extrapolated to the shear rate 3000s-1 using the law of force relationship.

B. Elongation Viscosity

Elongational viscosities are measured with a capillary viscometer (Geottert Co., Model Leograph 2003). Measure using a semi- hyperbolic die of diameter D 15 mm and length L 7.5 mm.

Semi-hyperbolic dies are defined by two equations. Z = axial distance from the original diameter, where D (z) is the diameter of the die at distance Z from Dinitial:

The die is attached to the bottom of the barrel and fixes the test temperature. The test temperature is at or above the melting point of the starch composition. The preheated sample composition is placed in the barrel portion of the viscometer to fill the barrel. In general, since air can form bubbles on the surface and cause problems in operation, compression can be performed to remove the air before the test operation. A piston is programmed to push the sample from the barrel into the die in the die at a constant speed. At this time, the pressure of the sample is lowered. The apparent viscosity of the composition can be obtained from the pressure drop and the flow rate of the sample through the hole.

Elongation Viscosity = (Delta P / Elongation / Eh) 105

Here, the elongational viscosity is represented by Pa.s. Delta P is the pressure drop and the unit is bar. Eh is a Henky variant. Henky variants are variants that depend on time or history. The deformations made by fluid elements in non-Newtonian fluids depend on their kinematic history. In other words,

The Henky variant of this design, determined by the equation, is 5.99.

Eh = In [(Dinitial / Dfinal) 2]

Apparent elongational viscosity is recorded as a function of elongation of 250-1 using the law of force relations. Elongational viscosity can also be measured using a hyperbolic or semi-hyperbolic die. This method is published in US Pat. No. 5,357,784.

C. Molecular Weight and Molecular Weight Distribution

Molecular weight (Mw) and molecular weight distribution (MWD) were determined by gel permeation chromatography using a mixed bed column. The device parts are as follows:

Pump Waters Model 600E

System Regulator Waters Model 600E

Automatic Sampler Waters Model 717 PLUS

Column length 600 mm, inner diameter 7.5 mmPL gel 20 μm mixing

Column A (gel molecular weight 1000 to 40000000)

Detector Waters Model 410 Differential Refractors GPC Soft

Ware Waters Millennium Software

The column is calibrated with dextran standards having molecular weights of 245000, 350000, 805000, and 2285000. These dextran are available from American Polymer Standard Corporation, Mentor, Ohio. Calibration standards are prepared in 2 mg / ml solution by dissolving the standard material in the fluidized bed. Gently stir and filter through an injection filter (5 μm nylon membrane, Spartan-25, VWR) using a syringe (5 ml, Non-Jject, manufactured by VWR). Samples are prepared from a gelatinized mixture by mixing 40% starch in water and heating. 1.55 g of gelatinized mixture is added to 22 g of fluidized phase to prepare a solution of 3 mg / ml, stirred for 5 minutes, then left in an oven at 105 ° C. for 1 hour and cooled to room temperature. The solution is filtered through an injection filter using the syringe above.

The filtered standard sample and the sample solution of interest are taken with an autosampler, then the previous sample is taken out in a 100 μl injection loop and the sample is injected into the column, fixing the column temperature to 70 ° C. The sample is eluted from the column to fix the differential refractive index detector at 50 ° C. and set the sensitivity range to 64 to measure against the fluidized bed background. The fluidized bed is DMSO dissolved 0.1% w / v LiBr. The flow rate is 1.0 ml / min and the flow bed is set to constant during operation. Each standard or sample is manipulated three times through GPC to obtain an average.

The molecular weight distribution is calculated by the following equation.

MWD = weight average molecular weight / number average molecular weight

D. Thermal Properties

The thermal properties of the starch compositions of the present invention are measured with a TA apparatus DSC-2910 calibrated with an indium metal standard with a melting point of 156.6 ° C. and a calorie of 6.80 cal / g. Standard DSC operation is done according to the manufacturer's operation manual. Due to volatilization (eg water vapor) during DSC measurements, a large-capacity fan with an O-ring seal is used to prevent the escape of volatiles from the sample. Samples and inert reference examples (typically empty pans) are heated at the same rate. When the phase of the sample changes, the heat flow of the sample and the inert reference example is measured with a DSC device. The device is connected to a computer that controls test conditions (heating / cooling rates) and collects, calculates and records data.

The sample is weighed into a pan and sealed with a 0-ring and a lid. Typical sample size is 25-65 milligrams. Place the sealed pan in the device and program the following thermal measurements with a computer.

1. equilibrate at 0 ° C .;

2. hold at 0 ° C. for 2 minutes;

3. Heating at 10 ° C./min to 120 ° C .;

4. hold at 120 ° C. for 2 minutes;

5. Cool at 10 ° C./min to 30 ° C .;

6. Equilibrate for 24 hours at room temperature, during which time the sample is removed from the DSC apparatus and placed in a controlled environment at 30 ° C .;

7. Equilibrate the sample to 0 ° C. by returning it to the DSC apparatus pan;

8. hold at 0 ° C. for 2 minutes;

9. Heat at 10 ° C./min to 120 ° C .;

10. hold at 120 ° C. for 2 minutes;

11. Cool at 10 ° C./min to 30 ° C .;

12. Remove used sample.

Compute and record thermal analysis results as differential heat flow (ΔH) vs. temperature or time with a computer. Differential heat flow is generally reported per weight (ie cal / mg). When the sample causes a phase transition, such as a glass transition, a ΔH vs. temperature / time plot is readily used to measure the glass transition temperature.

E. Water Soluble

Each component is mixed while heating to form a sample composition and stirred to form a uniform mixture. The molten composition is applied onto Teflon to cast into a thin film and cooled to room temperature. The film is completely dried in an oven at 100 ° C. and the dried film is cooled to room temperature and ground into small pellets.

To determine the percent solids of the sample, 2-4 g of sample is placed in a metal pan and the total weight of the sample and pan is recorded. Place the weighed pan and sample at 100 ° C for 2 hours, then weigh immediately. % Solids is calculated as follows:

% Solids = (Dry weight of sample and pan-pan weight) × 100 / (First weight of feed and pan-pan weight)

To determine the solubility of the sample composition, 10 g of sample is placed in a 250 ml beaker and poured with deionized water to a total weight of 100 g. Samples are mixed with water for 5 minutes on agitated plates and at least 2 ml of sample is poured into centrifuge tubes. Centrifuge for 1 hour at 10O < 0 > C at 20000 rpm. Take the supernatant and measure the refractive index. Solubility is calculated as follows:

Soluble Solid% = (Refractive Index #) × 1000 / Solid%

F. sideview

Prior to testing, the samples are placed under conditions of 48-50% relative humidity and 22-24 ° C. until the moisture content is 5-16%. Moisture content is measured by TGA (thermogravimetric analyzer). For thermogravimetric analysis, a high performance TGA2590 thermogravimetric analyzer from TA Instruments is used. Approximately 20 mg of sample is weighed and placed in a TGA pan. Insert the sample into the device and raise the temperature to 250 ° C. at 10 ° C./min. The moisture content of the sample is calculated as follows using weight loss;

Moisture% = (Initial Weight-250 ° C Weight) × 100 / Initial Weight

The sample is cut to a size larger than the foot used to measure the side diameter. The foot used has an area of 3.14 square inches.

The specimen is placed on a horizontal plane to define a load launcher having a horizontal plane and a horizontal load surface. Here, the load foot has a circular surface area of 3.14 square inches and exerts a defined pressure of 15 g / cm 2 (0.21 psi) on the sample. The side diameter is the production gap between the plane and the load surface of the load leg. The measurements were measured using a VIR electrical thickness meter model II, manufactured by Twin-Albert, Philadelphia. Sideview measurements were repeated five or more times. The results are reported in millimeters.

The total recorded in the sideview test was divided by the number of recordings and the result was recorded in millimeters.

Even if the embodiments of the present invention are not specifically mentioned, those skilled in the art can make various modifications without departing from the spirit and scope of the present invention.

Claims (23)

(a) providing a starch composition having an elongation viscosity of 50 Pa · s to 20,000 Pa · s; (b) electrospinning the starch composition to produce starch filaments of 0.001 to 135 dtex size. The process of claim 1, wherein providing the starch composition consists of providing a starch composition comprising starch having a weight-average molecular weight of 1,000 to 2,000,000. The process of claim 1, wherein in the electrospinning step of the starch composition, the starch composition has an intrinsic capillary number of at least 0.05. A process as claimed in claim 2 having at least one intrinsic capillary number. The process of claim 1, wherein providing the starch composition consists of providing a starch composition comprising starch containing 20 to 99% by weight amylopectin. 6. The process according to claim 5, wherein the starch composition comprises from 10 to 80% by weight of starch and from 20 to 90% by weight of additives and the elongation viscosity of the starch composition is from 100 Pa.s to 15,000 Pa.s. 6. The process according to claim 5, wherein the starch composition comprises 20 to 70 wt% starch and 30 to 80 wt% additive and the elongation viscosity of the starch composition is 200 Pa · s to 10,000 Pa · s. 6. The process according to claim 5, wherein the elongation viscosity of the starch composition is between 200 Pa.s and 10,000 Pa.s and the intrinsic capillary number is between 3 and 50. 6. The process according to claim 5, wherein the elongation viscosity of the starch composition is 300 Pa.s to 5,000 Pa.s and the intrinsic capillary number is 5 to 30. The process of claim 1, wherein providing the starch composition consists of providing a starch composition comprising a high molecular weight polymer compatible with the starch and having an average molecular weight of at least 500,000. The process of claim 1, wherein providing the starch composition consists of providing a starch composition comprising an additive selected from the group consisting of plasticizers and diluents. 12. The process of claim 11, wherein the starch composition further comprises from 5 to 95% by weight of a protein selected from the group consisting of corn protein, whole protein, wheat protein, or a combination thereof. The process of claim 1 further comprising attenuating the starch filaments with an air stream. (a) providing a starch composition having an elongation viscosity of 100 Pa · s to 10,000 Pa · s; (b) providing a molding member having a three-dimensional filament receiving side and a rear side opposite the pattern comprising a pattern selected from the group consisting of a substantially continuous pattern, a substantially continuous pattern, a discontinuous pattern, and a combination thereof; Making; (c) electrospinning the starch composition to produce a plurality of starch starch filaments; And (d) placing a plurality of starch filaments on the filament receiving side of the molding member such that the starch filaments follow a three-dimensional pattern on the filament receiving side. 15. The process of claim 14, wherein providing the starch composition comprises providing a starch composition comprising starch having a weight-average molecular weight of 1,000 to 2,000,000 and a high molecular weight polymer having an average molecular weight of at least 500,000. . 15. The process of claim 14, wherein the electrospinning step of the starch composition consists in electrospinning the starch composition through a die. 17. The process of claim 16 further comprising attenuating the starch filaments with an air stream. 15. The process of claim 14, wherein providing the molding member provides a molding member designed to run continuously in the machine direction. 15. The method of claim 14, wherein providing the molding member comprises: a molding member formed by a reinforcement device placed at a first height and a resinous structure connected face-to-face to the reinforcement device and extending outwardly from the reinforcement member to form a second height. Providing a process. 20. The process of claim 19, wherein the molding member is fluid permeable and comprises a plurality of interwoven yarns, felts, or a combination thereof. 21. The resinous structure of claim 20, wherein the resinous structure comprises a plurality of bases extending outward from the reinforcement member and a plurality of cantilever portions extending from the base at a second height to form a space between the cantilever portion and the reinforcement device. And the plurality of bases and the plurality of cantilever portions together form a three-dimensional filament receiving side of the molding member. 15. The process of claim 14, wherein placing the plurality of starch filaments on the filament receiving side of the molding member comprises applying a fluid pressure difference to the plurality of starch filaments. 23. The process of claim 22, wherein providing the starch composition consists in providing a starch composition comprising a high molecular weight polymer.