RU2671467C2 - Method of preparing pregelatinised, partially hydrolysed starch and related methods and products - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method of preparing starch. Disclosed method comprises mixing water, non-pregelatinised starch and an acid having pKvalue from 3 to 6, which does not substantially form chelates with calcium ions, to obtain a wet starch-containing precursor substance with a moisture content of 8 wt% to 25 wt%, feeding said wet starch precursor substance to an extruder, pregelatinisation and acid modification of said wet starch in the extruder at a head temperature of 150 °C to 210 °C, wherein the pregelatinised, partially hydrolysed starch is characterised by a degree of gelatinization of at least 70 % and a viscosity in cold water (10 % solids, 25 °C) of 10 Brabender units (BU) to 120 BU.EFFECT: invention provides an easily digestible starch.6 cl, 3 dwg, 11 tbl, 4 ex

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[001] This application claims priority based on US Application No. 14/044582, filed October 2, 2013, PCT International Application No. PCT / US2013 / 064776, filed October 14, 2013, and US Application No. 14/494547, filed September 23, 2014 years, while the contents of all of these previous patent applications in full are incorporated herein by reference.

BACKGROUND

[001] Starches usually contain two types of polysaccharides (amylose and amylopectin) and are classified as carbohydrates. Some starches are pre-gelled (pre-gelatinized), usually using thermal methods. In general, pregelatinized starches can form dispersions, pastes or gels with cold water. In general, pregelatinized starches are easily digestible and are used in various ways, including as an additive in various food products (for example, in baked goods, snacks, drinks, confectionery, dairy products, sauces, convenience foods, seasonings and meat products) and in pharmaceutical drugs.

[002] Another application of pregelatinized starches is the manufacture of a gypsum wallboard. However, in the manufacture of the slab, building gypsum (i.e. calcined gypsum in the form of calcium sulfate hemihydrate and / or calcium sulfate anhydrite), water, starch and other ingredients, if necessary, are mixed, usually in a finger mixer (the term used in this field technology). A suspension is obtained and unloaded from the mixer onto a moving conveyor carrying a covering sheet with one of the overlay layers (if present) that has already been applied (often to the mixer). The suspension is spread on top of the paper (with a topcoat, optionally placed on paper). Another casing sheet, with or without a topcoat, is applied to the suspension using, for example, a forming plate or the like. and get a layered structure of the required thickness.

[003] The mixture is cast and allowed to solidify to form trapped (ie, rehydrated) gypsum by reacting the calcined gypsum with water to form a crystalline hydrated gypsum matrix (ie, calcium sulfate dihydrate). It is the required hydration of the calcined gypsum that makes it possible to form an interlocked matrix of crystals of the captured gypsum, which thereby gives strength to the gypsum structure in the product. To obtain a dry product, heat is required (for example, in a kiln) to remove the remaining free (i.e., unreacted) water.

[004] Pregelatinized starches often increase the water consumption of this process. To compensate for water consumption and ensure sufficient fluidity during production, it is necessary to add water to the stucco slurry. Such an excess of water makes production inefficient, including increasing the drying time, reducing the speed of production lines and increasing energy costs. The inventors of the present invention have found that pregelatinized and partially hydrolyzed starch requires less water.

[005] The inventors of the present invention also found that methods for preparing pregelatinized partially hydrolyzed starches were not completely satisfactory. Conventional methods for producing such pregelatinized partially hydrolyzed starches are not effective, have a low yield and low productivity, as well as high energy costs. Thus, there is a need in the art for an improved process for the preparation of pregelatinized partially hydrolyzed starch, in particular with a low need for water.

[006] It should be understood that such a description of the prior art was made by the authors of the present invention to help the reader, and should not be construed either as a reference to the prior art, or as an indication that any of these problems were themselves recognized in the art. Although the principles described may in some respects and implementations of the invention alleviate the problems inherent in other systems, it should be understood that the scope of the protected innovation is determined by the appended claims, and not by the ability of the claimed invention to solve any particular problem mentioned in this document.

SUMMARY OF THE INVENTION

[007] According to one aspect, the present invention provides a method for producing pregelatinized partially hydrolyzed starch, comprising: (a) mixing at least water, non-pregelatinized starch and a weak acid that essentially does not form chelates with calcium ions to produce a wet starch-containing substance precursor with a moisture content of from about 8% of the mass. up to about 25% of the mass .; (b) feeding said wet starch precursor to the extruder; and (c) pre-gelatinization and acid modification of the wet starch-containing precursor substance in the extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF). The invention also proposed starch obtained according to the specified method.

[008] According to another aspect, the present invention provides a method for producing pregelatinized partially hydrolyzed starch, comprising: (a) mixing at least water, non-pregelatinized starch and a strong acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% of the mass., while a strong acid is present in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch; (b) feeding the wet starch to the extruder; and (c) pre-gelatinization and acid modification of the wet starch-containing precursor substance in the extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF). The invention also proposed starch obtained according to the specified method.

[009] According to another aspect, the present invention provides a method for making a plate comprising: (a) preparing pregelatinized partially hydrolyzed starch by (i) mixing at least water, ungelatinized starch and acid to produce a wet starch-containing precursor substance with a moisture content of from about 8% mass up to about 25% wt., while the acid is selected from the group consisting of: (1) a weak acid, which essentially does not form chelates with calcium ions, (2) a strong acid in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch or (3) any combination thereof; (ii) feeding the wet starch-containing precursor to the extruder; and (iii) pregelatinization and acid modification of wet starch in a die-type extruder at a temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF); (b) mixing pregelatinized and partially hydrolyzed starch with at least water and gypsum to form a slurry; (c) placing the suspension between the first cladding sheet and the second cladding sheet to obtain a wet precast structure; (d) cutting a wet prefabricated structure to form a slab; and (e) drying the stove. According to some embodiments of the invention, the captured gypsum core has a compressive strength greater than the captured gypsum core made using starch obtained according to another method. According to another aspect, the present invention provides a cooker prepared according to the method.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0010] FIG. 1 is an amylogram obtained by plotting the values of viscosity (left y axis) and temperature (right y axis) versus time (x axis), which shows the bonding profiles of starches extruded with a moisture content of 16% by weight, while the solid content phase in the test suspension is 10 wt. -%, as described in example 2.

[0011] FIG. 2 is an amylogram, an amylogram obtained by plotting the values of viscosity (left y axis) and temperature (right y axis) versus time (x axis), which shows the bonding profiles of starches extruded with a moisture content of 13% by weight, while the solids content in the test suspension is 10% by mass, as described in example 2.

[0012] FIG. 3 is a graph of temperature versus time showing the hydration rate at a given temperature increase (TRS) of two suspensions containing pregelatinized partially hydrolyzed starches treated with alum in an amount of 3% by weight. and retarder setting in quantities of 0.05% of the mass. and 0.0625 wt.%, respectively, and a third suspension containing ordinary pregelatinized corn starch with a viscosity of 773 centipoise and setting retarder in an amount of 0.05 wt.%, as described in example 3.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiments of the present invention provide methods for the preparation of pregelatinized partially hydrolyzed starches. According to one aspect, the present invention provides a method for manufacturing a plate (e.g., a gypsum wall plate). The pregelatinized partially hydrolyzed starches obtained according to the method proposed in the present invention can be used in various other ways, for example, in food products (for example, in bakery products, drinks, confectionery, dairy products, instant puddings, sauces, soup mixes, convenience foods , pie fillings, seasonings and meat products), pharmaceuticals, feed, adhesives and paints. Such starches obtained according to some variants of implementation of the present invention, as a rule, are easily digestible and allow to obtain food products with the desired viscosity and preserve most of the functional properties of the starting base material.

[0014] Embodiments of the present invention are based, at least in part, on the surprising and unexpected discovery of the possibility of pregelatinization and acid modification of starch in an extruder in a single step. It is surprising and unexpected that pregelatinization and acid modification of starch in one step in an extruder has significant advantages compared with pregelatinization and acid modification of starch in separate stages. For example, the inventive method for producing pregelatinized partially hydrolyzed starch provides a higher yield, faster production and lower energy costs while maintaining the desired properties (e.g., viscosity, fluidity, solubility in cold water, etc.), as described herein document.

[0015] In addition, it has been found that extrusion conditions (eg, high temperature and high pressure) can significantly increase the rate of acid hydrolysis of starch. It is surprising and unexpected that such a one-step process makes it possible to use a weak acid, such as alum, and / or smaller amounts of a strong acid to carry out an acid modification of starch. Both acid forms provide a mechanism in which protons from an acid catalyze the hydrolysis of starch. Conventional acid modification methods include purification and neutralization steps. According to some embodiments of the present invention, the use of a weak acid (e.g. alum) and / or a small amount of a strong acid eliminates the need for any neutralization step and subsequent purification step, typically necessary in conventional systems for purifying starch from salts formed in the step neutralization.

[0016] According to embodiments of the present invention, the proposed extrusion method not only allows gelatinization of starch, but also partially hydrolyzes (ie, by acid modification) of starch molecules. Thus, the extrusion process in one stage provides both physical modification (pre-gelatinization) and chemical modification (acid modification, partially acid hydrolysis). Pregelatinization provides starch with the ability to give strength (for example, to a final product, such as a gypsum board). Acid modification allows partial starch hydrolysis to be successfully hydrolyzed, providing starch with the ability to give strength to the final product, such as gypsum board, and providing low water consumption in the production of products, for example, in the case of gypsum board manufacturing processes. Thus, the product produced according to the starch production methods proposed in the embodiments of the present invention is pregelatinized and partially hydrolyzed starch.

[0017] In some embodiments, the present invention provides a highly effective acid modification reaction. The pre-gelatinization and acid modification in the extruder occurs at elevated temperatures and / or pressures, as described herein, and can lead to an acid hydrolysis rate that can be, for example, approximately 30,000 times or faster than conventional acid hydrolysis at lower temperatures (e.g. 50 ºC) and / or pressures. The rate of acid hydrolysis is further increased by applying low levels of moisture (from about 8% to about 25% by weight) in a starch-containing precursor substance and, therefore, due to the increased concentration of reagents. Due to such a high efficiency of acid modification, the inventors surprisingly and unexpectedly found that a weak acid or a very low level of strong acid can be used in a starch-containing precursor substance to ensure optimal acid modification and eliminate the need for neutralization and purification, which are expensive, time consuming and represent inefficient requirements of conventional systems.

[0018] According to some embodiments of the invention, hydrolysis is used to convert starch into smaller molecules within the optimal size range that is defined herein depending on the desired viscosity of the pre-gelatinized partially hydrolyzed starch. If the starch is subjected to excessive hydrolysis, it can turn into too small molecules (for example, oligosaccharides or sugars), which in the case of a gypsum board can lead to less board strength than that given by pregelatinized partially hydrolyzed starch of the required viscosity.

[0019] Pre-gelatinized partially hydrolyzed starch can be obtained by (i) mixing at least water, non-gelatinized starch and acid to produce a wet starch-containing precursor substance with a moisture content of from about 8% by weight. up to about 25% of the mass. The acid may be: (1) a weak acid which essentially does not form chelates with calcium ions, (2) a strong acid in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch; or (3) any combination thereof. The wet starch-containing precursor is subjected to pregelatinization and acid modification in an extruder in a single step at elevated head temperature and / or pressure, as described herein. Starch is hydrolyzed to the extent that it provides the desired viscosity, for example, as described herein.

[0020] Thus, according to some embodiments of the invention, pregelatinized partially hydrolyzed starch can be obtained by mixing at least water, non-pregelatinized starch and a weak acid, which essentially does not form chelates with calcium ions, to obtain a wet starch-containing precursor substance with moisture content from about 8% of the mass. up to about 25% of the mass. Wet starch is then fed to the extruder. Being in the extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF), wet starch undergoes gelatinization and acid modification so that it is at least partially hydrolyzed.

[0021] According to additional embodiments of the invention, pregelatinized partially hydrolyzed starch can be obtained by mixing at least water, ungelatinized starch and a strong acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% of the mass., while a strong acid is present in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch. Wet starch is then fed to the extruder. Being in the extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF), wet starch undergoes gelatinization and acid modification so that it is at least partially hydrolyzed.

[0022] It is advisable if the resulting pregelatinized partially hydrolyzed starch is characterized by a low water consumption when introduced into the plaster slurry and, according to some embodiments of the invention, it can be used in the manufacture of a plate (for example, gypsum board) with good strength. Thus, according to another aspect, the present invention provides a method for manufacturing a gypsum board using starch obtained in a single step in an extruder using the pregelatinization and acid modification methods of the invention. According to some embodiments of the invention, the pre-gelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention are characterized by low water consumption compared to other pregelatinized starches known in the art.

[0023] As a result, the pre-gelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention can be incorporated into the stucco suspension (for example, by means of a feed line in a finger mixer) with good flowability. In some embodiments of the invention, higher amounts of pregelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention can be included since there is no need to add excess water to the system, so that even higher strengths and lower board densities can be achieved. The resulting board exhibits good strength properties (for example, it has good core hardness, resistance to pulling nails, compressive strength, etc., or any ratio between them, based on any combination of the values of each parameter described herein). The inclusion of starch obtained according to the method proposed in the present invention, in the manufacture of gypsum boards preferably allows you to produce an ultralow density product due to increased strength. The gypsum board may be in the form of, for example, a gypsum wallboard (often referred to as dry building gypsum), which may include such a board, used not only for walls, but also for ceilings and other places as is known in the art. However, starch obtained according to the proposed method may have other uses, for example, in food products.

Pre-gelatinization and acid modification

[0024] Starches are carbohydrates and contain two types of polysaccharides, namely linear amylose and branched amylopectin. Starch grains are semi-crystalline, for example, as seen in polarized light, and are not soluble at room temperature. Gelatinization is a process in which starch is placed in water and heated (“boiled”), so that the crystalline structure of starch grains melts and the starch molecules dissolve in water, forming a good dispersion. It has been found that when starch grains are converted to a gelled form at the beginning, starch grains provide a low viscosity in water, since starch grains are insoluble in water. As the temperature rises, the starch grain swells and the crystalline structure melts at the pre-gelatinization temperature. Maximum viscosity is achieved with maximum swelling of starch grains. Further heating will lead to the destruction of starch grains and the dissolution of starch molecules in water with a sharp drop in viscosity. After cooling, the starch molecule will be re-associated with the formation of a 3-D gel-like structure, and the viscosity increases due to the gel-like structure. Some commercial starches are sold in pre-gelatinized form, while others are sold in granular form. According to some embodiments of the present invention, with respect to the gypsum board, the granular form undergoes at least some degree of gelatinization. To illustrate, with respect to the gypsum board, the starch is subjected to pregelatinization before being added to the gypsum slurry, also referred to herein as a stucco slurry (usually in a mixer, for example a finger mixer).

[0025] Thus, as used herein, “pregelatinized” means that starch has any degree of pregelatinization, for example, before being added to a gypsum slurry or when used in other applications. In some gypsum board embodiments, pregelatinized starch can be partially gelled when added to the suspension, but becomes completely gelled when exposed to elevated temperature, for example, in a kiln during the drying step to remove excess water. In some gypsum board embodiments of the invention, the pregelatinized starch is not completely gelled even when leaving the kiln, provided that the starch corresponds to a mid-range viscosity characteristic according to some embodiments of the invention under conditions according to the method based on the viscosity modifying additive (VMA).

[0026] When referring to viscosity herein, said viscosity is measured according to the VMA method, unless otherwise indicated. According to the described method, the viscosity is measured using a Discovery HR-2 Hybrid Rheometer (TA Instruments Ltd) equipped with a concentric cylinder, a standard cup (30 mm in diameter) with blade geometry (28 mm in diameter and 42.05 m long).

[0027] After receiving the starch to determine whether the starch is fully gelled, differential scanning calorimetry (DSC) methods are used. The DSC step can be used to observe whether the starch is fully gelled, for example, to confirm the absence of retrograde. One of two methods is used depending on the temperature necessary for the complete gelatinization of starch, which can also be determined using DSC, as will be understood by a person of ordinary skill in the art.

[0028] Method 1 is used when the DSC data indicates that the starch is fully gelled or has a gelatinization temperature of 90 ° C. or lower. Method 2 is used when the gelatinization temperature is above 90 ° C. Since the viscosity is measured when the starch is in water, method 2 uses pressure cooking in an airtight vessel, which ensures overheating to temperatures above 100 ° C without noticeable evaporation of water. Method 1 is intended for starches that are already fully gelled, or for starches with a gelatinization temperature of up to 90 ° C, because, as described below, gelatinization occurs in a rheometer, which is an open system and in which it is impossible to create high pressure conditions for gelatinization. Thus, in the case of starches with higher gelatinization temperatures, Method 2 is used. In any case, when measuring viscosity, starch (7.5 g based on dry weight) is added to water to provide a total weight of 50 g.

[0029] In Method 1, starch is dispersed in water (15% starch of the total mass of starch and water) and the sample is immediately transferred to a cylindrical cell. The cell is coated with aluminum foil. The sample is heated from 25 ° C to 90 ° C at a speed of 5 ° C / min and a shear rate of 200 sec ^-1 . The sample is maintained at 90 ° C for 10 min at a shear rate of 200 sec ^-1 . The sample is cooled from 90 ° C to 80 ° C at a speed of 5 ° C / min and a shear rate of 200 sec ^-1 . The sample is maintained at 80 ° C for 10 min at a shear rate of 0 sec ^-1 . The viscosity of the sample is measured at 80 ° C and a shear rate of 100 sec ^-1 for 2 minutes. Viscosity is an average measurement from 30 seconds to 60 seconds.

[0030] Method 2 is used for starches with a gelatinization temperature of more than 90 ° C. The starch is gelled according to methods well known in the production of starch (for example, by cooking under pressure). An aqueous solution of gelled starch (15% of the total mass) is immediately transferred to the measuring cup of the rheometer and brought into equilibrium at 80 ° C for 10 minutes. The viscosity of the sample is measured at 80 ° C and a shear rate of 100 sec ^-1 for 2 minutes. Viscosity is an average measurement from 30 seconds to 60 seconds.

[0031] A visograph and DSC are two other methods for describing gelatinization of starch. The degree of gelatinization of starch can be determined using, for example, a thermogram obtained by the DSC method, for example, using the peak area (crystal melting) to calculate. A visogram (obtained on a visograph) is less desirable for determining the degree of partial gelation, but it is a good tool for obtaining data such as changes in starch viscosity, maximum gelatinization, gelatinization temperature, retrograde, aging viscosity, viscosity at the end of cooling, etc. . To determine the degree of gelation, DSC measurements are performed in the presence of excess water, in particular at 67% by weight or higher. When the water content in the starch / water mixture is less than 67%, the gelatinization temperature will increase as the water content decreases. Starch crystals are difficult to melt when the amount of available water is limited. When the water content in the starch / water mixture reaches 67%, the gelatinization temperature will remain constant regardless of how much more water is added to the starch / water mixture. The gelatinization start temperature indicates the initial gelatinization temperature. The gelatinization end temperature indicates the final gelatinization temperature. Gelatinization enthalpy reflects the amount of crystalline structure melted during gelatinization. Using the enthalpy obtained from the DSC thermogram of starch, the degree of gelation can be determined.

[0032] Other starches have different gelatinization start temperatures, gelatinization end temperatures, and gelatinization enthalpies. Therefore, other starches can become completely gelled at other temperatures. It should be understood that starch is completely gelled when it is heated above the final gelatinization temperature with excess water. In addition, for any particular starch, when the starch is heated below the final gelatinization temperature, the starch will partially gel. Thus, partial and incomplete gelatinization will occur in the presence of excess water when the starch is heated below the gelatinization end temperature, for example, as determined by DSC. Complete gelatinization will occur in the presence of excess water when the starch is heated above the gelatinization end temperature, for example, as determined by DSC. The degree of gelation can be controlled in various ways, such as, for example, by heating the starch below the gelatinization end temperature, which leads to partial gelation. For example, if the enthalpy required for complete gelatinization of starch is 4 J / g, while DSC data shows that the gelatinization enthalpy of starch is only 2 J / g, this means that 50% of the starch was gelled. Fully gelatinized starch will not have a gelatinization peak on a DSC thermogram (enthalpy = 0 J / g) when measured with a DSC.

[0033] As noted, the degree of gelation may have any suitable value, such as about 70% or more, and the like. However, lower degrees of gelatinization will be more consistent with granular starch and will not allow to take full advantage of the advantages of increased strength, better (more complete) dispersion and / or reduced water consumption, according to some embodiments of the present invention. Thus, according to some embodiments of the invention, it is preferable that there is a higher degree of gelation, for example at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, at least about 99%, or complete (100%) gelation. Starch with a lower degree of gelatinization can be added to the suspension, and in the case of gypsum in the kiln, additional gelation occurs (for example, up to 100%). From the point of view of adding to the suspension, by “fully gelled” it should be understood that the starch is sufficiently digested at its gelatinization temperature or higher or otherwise ensures complete gelatinization, as can be seen from the DSC data. Although a slight degree of retrograde can be expected upon cooling, according to some embodiments of the invention, starch should still be considered “completely gelled” in terms of adding to a gypsum slurry or applying to other products, as will be appreciated by one of ordinary skill in the art. On the contrary, from the point of view of the VMA method discussed herein, when performing a viscosity measurement, such a retrograde is not acceptable.

[0034] The starch molecule can be subjected to acid modification, for example, to effect hydrolysis of glycosidic bonds between glucose units and provide the desired molecular weight. One of the advantages of acid modification of starch, which provides a decrease in molecular weight, is that water consumption will decrease. Conventional pregelatinized starches, which were also not modified with acid, are characterized by very high water consumption, which is accompanied by higher energy costs. It was generally believed that it is generally preferable when such a modification occurs before gelation, since it is usually more effective and less highly costly. However, surprisingly and unexpectedly, the inventors found that gelatinization and acid modification can be combined in one stage so that these processes can occur simultaneously, rather than sequentially.

The method of obtaining starch

[0035] According to some embodiments of the present invention, wet starch-containing precursor is obtained before entering the extruder. Wet starch-containing precursor can be obtained by any suitable method. For example, in some embodiments, a wet starch precursor is obtained by adding raw water and an acid to the starch, which is (a) a weak acid that does not substantially form chelates with calcium ions, and / or (b) a strong acid in a small quantity.

[0036] Any suitable starch-containing raw material can be selected to produce a wet starch-containing precursor material, provided that it can be used to produce pregelatinized partially hydrolyzed starch, such as starch, corresponding to a mid-range viscosity characteristic according to some embodiments of the present invention. As used herein, “starch” refers to a composition comprising a starch component. Essentially, the starch may be 100% pure starch or may contain other components, such as those typically found in flour, such as protein and fiber, provided that the starch component is at least about 75% by weight relative to the mass of starch composition. The starch may be in the form of flour (eg, corn flour) containing starch, for example, flour containing at least about 75% starch by weight relative to the weight of the flour, for example at least about 80%, at least about 85%, at least about 90%, at least about 95%, and the like). Any suitable unmodified starch or flour can be used to prepare the pre-gelatinized partially hydrolyzed starches precursor of the invention. For example, the starch may be CCM260 yellow corn flour, CCF600 yellow corn flour (Bunge North America), Clinton 106 (ADM) and / or Midsol 50 (MGP Ingredients).

[0037] A wet starch precursor substance having any suitable moisture content can be obtained so that the desired levels of gelatinization and acid modification can be achieved in the extruder. According to some variants of implementation of the invention, for example, it is desirable that the wet starch-containing precursor substance has a moisture content of from about 8% of the mass. up to about 25% of the mass. by weight relative to the total mass of starch-containing precursor, for example, from about 8% of the mass. up to about 23% of the mass., for example, from about 8% of the mass. up to about 21% of the mass., from about 8% of the mass. up to about 20% of the mass., from about 8% of the mass. up to about 19% of the mass., from about 8% of the mass. up to about 18% of the mass., from about 8% of the mass. up to about 17% of the mass., from about 8% of the mass. up to about 16% of the mass., from about 8% of the mass. up to about 15% of the mass., from about 9% of the mass. up to about 25% of the mass., from about 9% of the mass. up to about 23% of the mass., from about 9% of the mass. up to about 21% of the mass., from about 9% of the mass. up to about 20% of the mass., from about 9% of the mass. up to about 19% of the mass., from about 9% of the mass. up to about 18% of the mass., from about 9% of the mass. up to about 17% of the mass., from about 9% of the mass. up to about 16% of the mass., from about 9% of the mass. up to about 15% of the mass., from about 10% of the mass. up to about 25% of the mass., from about 10% of the mass. up to about 23% of the mass., from about 10% of the mass. up to about 21% of the mass., from about 10% of the mass. up to about 20% of the mass., from about 10% of the mass. up to about 19% of the mass., from about 10% of the mass. up to about 18% of the mass., from about 10% of the mass. up to about 17% of the mass., from about 10% of the mass. up to about 16% of the mass., from about 10% of the mass. up to about 15% of the mass., from about 11% of the mass. up to about 25% of the mass., from about 11% of the mass. up to about 23% of the mass., from about 11% of the mass. up to about 21% of the mass., from about 11% of the mass. up to about 20% of the mass., from about 11% of the mass. up to about 19% of the mass., from about 11% of the mass. up to about 18% of the mass., from about 11% of the mass. up to about 17% of the mass., from about 11% of the mass. up to about 16% of the mass., from about 11% of the mass. up to about 15% of the mass., from about 12% of the mass. up to about 25% of the mass., from about 12% of the mass. up to about 23% of the mass., from about 12% of the mass. up to about 21% of the mass., from about 12% of the mass. up to about 20% of the mass., from about 12% of the mass. up to about 19% of the mass., from about 12% of the mass. up to about 18% of the mass., from about 12% of the mass. up to about 17% of the mass., from about 12% of the mass. up to about 16% of the mass., from about 12% of the mass. up to about 15% of the mass., from about 13% of the mass. up to about 25% of the mass., from about 13% of the mass. up to about 23% of the mass., from about 13% of the mass. up to about 21% of the mass., from about 13% of the mass. up to about 20% of the mass., from about 13% of the mass. up to about 19% of the mass., from about 13% of the mass. up to about 18% of the mass., from about 13% of the mass. up to about 17% of the mass., from about 13% of the mass. up to about 16% of the mass., from about 13% of the mass. up to about 15% of the mass., from about 14% of the mass. up to about 25% of the mass., from about 14% of the mass. up to about 23% of the mass., from about 14% of the mass. up to about 21% of the mass., from about 14% of the mass. up to about 20% of the mass., from about 14% of the mass. up to about 19% of the mass., from about 14% of the mass. up to about 18% of the mass., from about 14% of the mass. up to about 17% of the mass., from about 14% of the mass. up to about 16% of the mass. or from about 14% of the mass. up to about 15% of the mass. based on the total weight of the wet starch-containing precursor. It should be understood that upon receipt of wet starch, the moisture content provided herein includes environmental moisture as well as added water.

[0038] Not wanting to be bound by any particular theory, it is believed that lower moisture content leads to more friction in the extruder. According to some embodiments of the invention, it is possible to obtain wet starch having a moisture content that provides sufficient mechanical energy consumption when loading wet starch through an extruder so that friction prevents wet starch from moving too easily through the extruder. Increased friction can enhance the destruction of hydrogen bonds in starch.

[0039] Any suitable mild acid that substantially does not form chelates with calcium ions can be mixed into wet starch. Not wanting to be bound by any particular theory, chelation involves a weak acid, for example, forming a coordination complex with calcium or otherwise preventing the formation of gypsum crystals inside the gypsum slurry. Such an interfering effect may be a decrease in the number of gypsum crystals formed, a slowdown (decrease in speed) of crystal formation, a decrease in interactions between gypsum crystals, and the like. The term "essentially" in relation to the absence of chelation of calcium ions generally means that at least 90% (for example, at least 92%, at least 95%, at least 96%, at least 97%, at least at least 98% or at least 99%) of the existing calcium ions do not form chelating compounds with acid.

[0040] Weak acids according to embodiments of the present invention can be defined as acids having a pKa value of from about 1 to about 6, for example, from about 1 to about 5, from about 1 to 4, from about 1 to 3, from about 1 to 2, from about 1.2 to about 6, from about 1.2 to about 5, from about 1.2 to about 4, from about 1.2 to about 3, from about 1.2 to about 2, from about 2 to about 6, from about 2 to about 5, from about 2 to about 4, from about 2 to about 3, from about 3 to about 6, from about 3 to about 5, from when ERNO 3 to about 4, from about 4 to about 6, or from about 4 to about 5. As is well known in the art, pKa value is a measure of acid strength; the lower the pKa value, the stronger the acid.

[0041] Weak acids, which essentially do not form chelates with calcium ions, are characterized, for example, by the absence of multibinding sites, such as several carboxy functional groups (COO-), which usually bind calcium ions. In some embodiments, the weak acid has a minimal number of multibinding sites, such as multi-COO groups, or essentially does not contain multibinding sites, such as multi-COO groups, so that, for example, chelation is minimal (i.e. substantially eliminated) or the formation of gypsum crystals is essentially not affected compared to the formation of crystals in the absence of a weak acid. According to some embodiments of the invention, for example, aluminum sulfate (alum) is a weak acid suitable for use in the preparation of wet starch, since said aluminum sulfate essentially does not form chelates with calcium ions. Alum does not have multi-binding sites.

[0042] According to some embodiments of the invention, alum is added to the wet starch precursor in any suitable form, for example, in a liquid containing alum with the desired solid content. For example, liquid alum can be included in an aqueous solution in which alum is present in any suitable amount. Similarly, other weak acids may be added.

[0043] Wet starch can be mixed to include any suitable amount of a weak acid, which essentially does not form chelates with calcium ions, so that pre-gelatinized partially hydrolyzed starch with the desired viscosity and low water consumption is obtained, while the starch does not undergo excessive hydrolysis and does not turn into sugar. For example, according to some variants of the invention, the specified weak acid is added in an amount of from about 0.5% of the mass. up to about 5% of the mass. based on the mass of starch, for example, from about 0.5% of the mass. up to about 4.5% of the mass., for example, from about 0.5% of the mass. up to about 4% of the mass., from about 0.5% of the mass. up to about 3.5% of the mass., from about 0.5% of the mass. up to about 3% of the mass., from about 1% of the mass. up to about 5% of the mass., from about 1% of the mass. up to about 4.5% of the mass., from about 1% of the mass. up to about 4% of the mass., from about 1% of the mass. up to about 3.5% of the mass., from about 1% of the mass. up to about 3% of the mass., from about 1.5% of the mass. up to about 5% of the mass., from about 1.5% of the mass. up to about 4.5% of the mass., from about 1.5% of the mass. up to about 4% of the mass., from about 1.5% of the mass. up to about 3.5% of the mass., from about 1.5% of the mass. up to about 3% of the mass., from about 2% of the mass. up to about 5% of the mass., from about 2% of the mass. up to about 4.5% of the mass., from about 2% of the mass. up to about 4% of the mass., from about 2% of the mass. up to about 3.5% of the mass., from about 2% of the mass. up to about 3% of the mass., from about 2.5% of the mass. up to about 5% of the mass., from about 2.5% of the mass. up to about 4.5% of the mass., from about 2.5% of the mass. up to about 4% of the mass., from about 2.5% of the mass. up to about 3.5% of the mass. or from about 2.5% of the mass. up to about 3% of the mass. It should be understood that the listed amounts include a weak acid component, and when the weak acid is in solution, do not include water or other components of the solution.

[0044] A wet starch-containing precursor substance can be prepared, optionally additionally containing pseudo acids, which can form chelating compounds with a calcium ion, such as tartaric acid. Thus, according to some embodiments of the invention, a pseudo acid, such as tartaric acid, can be combined with any suitable weak acid that does not form chelating compounds with calcium ions. As you know, tartaric acid slows down the crystallization of gypsum. However, in combination with a weak acid that does not form chelate compounds, tartaric acid prevents a significant slowdown in the crystallization of gypsum, so that the hydrolysis reaction is optimized due to acid modification. In addition to tartaric acid, other pseudo-acids, such as succinic acid or malic acid, may be useful, provided that they do not exceed the accelerating effect of alum. In some embodiments, the wet starch precursor comprises both alum and tartaric acid.

[0045] When included, pseudo acids (eg, tartaric acid) may be present in any suitable amount. For example, tartaric acid may be present in an amount of from about 0.1% of the mass. up to about 0.6% of the mass. based on the mass of starch, for example, from about 0.1% of the mass. up to about 0.4% of the mass., from about 0.2% of the mass. up to about 0.3% of the mass.

[0046] According to some embodiments of the invention, oil can be added to wet starch, although not necessarily, to improve the mobility of starch within the extruder. In some embodiments, possible oils include canola oil, vegetable oil, corn oil, soybean oil, or any combination thereof. For example, according to some variants of the invention, canola oil or one of the above substitutes can be, although not necessarily, added in an amount of from about 0% of the mass. up to about 0.25% of the mass. by weight relative to the mass of starch, for example, from about 0.1% of the mass. up to about 0.2% of the mass., from about 0.1% of the mass. to about 0.15% of the mass., from about 0.15% of the mass. to about 0.25% of the mass., from about 0.15% of the mass. up to about 0.2% of the mass. or from about 0.2% of the mass. up to about 0.25% of the mass.

[0047] According to some embodiments of the invention, a wet starch-containing precursor is obtained by mixing water, non-gelatinized starch and a small amount of strong acid. In some embodiments, the pKa of the strong acid is about -1.7 or less. Any such strong acid can be used, while according to some embodiments of the invention, the strong acid contains sulfuric acid, nitric acid, hydrochloric acid, or any combination thereof. In some embodiments, sulfuric acid, alone or in combination with other acids, is preferred since a sulfate ion can accelerate the crystallization of gypsum in gypsum board embodiments.

[0048] The amount of strong acid is relatively small, such as about 0.05% of the mass. or less by weight relative to the mass of starch, for example, about 0.045% of the mass. or less, about 0.04% of the mass. or less, about 0.035% of the mass. or less, about 0.03% of the mass. or less, about 0.025% of the mass. or less, about 0.02% of the mass. or less, about 0.015% of the mass. or less, about 0.01% of the mass. or less, about 0.005% of the mass. or less, about 0.001% of the mass. or less, about 0,0005% of the mass. or less, for example, from about 0.0001% of the mass. up to about 0.05% of the mass., from about 0.0001% of the mass. up to about 0.045% of the mass., from about 0.0001% of the mass. up to about 0.04% of the mass., from about 0.0001% of the mass. to about 0.035% of the mass., from about 0.0001% of the mass. up to about 0.03% of the mass., from about 0.0001% of the mass. to about 0.025% of the mass., from about about 0.0001% of the mass. up to about 0.02% of the mass., from about 0.0001% of the mass. to about 0.015% of the mass., from about 0.0001% of the mass. to about 0.01% of the mass., from about 0.0001% of the mass. to about 0.005% of the mass., from about 0.0001% of the mass. to about 0.001% of the mass., from about 0.0001% of the mass. up to about 0.0005% of the mass. by weight relative to the mass of starch. It should be understood that these amounts include a strong acid component, and when the strong acid is in solution, do not include water or other components of the solution. For example, in the usual modification with strong acid, a 2% sulfuric acid solution with a solid starch phase content of ~ 35% (2 g of sulfuric acid per 35 g of starch) is used. The percentage is based on pure sulfuric acid components. The indicated content is calculated as the mass of the sulfuric acid component divided by the mass of wet starch. For example, if the purity of sulfuric acid is 50% (which means that half the mass of the solution is pure sulfuric acid), then the mass of the sulfuric acid solution is doubled. To illustrate, to provide a concentration of 0.1% of the mass. per 100 g of starch add 0.1 g of pure sulfuric acid. If the concentration of the sulfuric acid solution is 50%, to ensure a concentration of 0.1% of the mass. add 0.2 g of a 50% solution of sulfuric acid.

[0049] It should be understood that there are different brands of acids (> 95%, 98%, 99.99%). These differences are taken into account by the term “about” with respect to the amount of strong acid in the starch-containing precursor. A person of ordinary skill in the art can easily determine the% by weight described in this document used to incorporate other brands of acid. The amounts of strong acid used according to some embodiments of the present invention are significantly less than the amounts that were added to the conventional systems used, for example at least about 2 g of sulfuric acid per 35 g of starch. In some embodiments, the strong acid in small amounts, as described above, can be used in combination with a weak acid that does not form chelating compounds with calcium ions, such as the alum described herein.

[0050] Embodiments of the present invention feed the wet starch precursor through an extruder so that the wet starch precursor is subjected to pregelatinization and acid modification in an extruder in a single step. It should be understood that the extruder is a machine, usually used for melting and processing polymers to obtain the desired shape by melting the polymer and pumping it through the head. The extruder also allows the polymer to be mixed with other ingredients such as dye, reinforcing fibers, mineral fillers, and the like. The purpose of the extruder is to disperse and distribute all the ingredients loaded into it and to melt these ingredients at a constant temperature and pressure.

[0051] Configurations and devices for extruders are known in the art. In general, the extruder comprises a feed hopper for delivering feed material, a pre-conditioner comprising heating jackets for conditioning the polymer with a plasticizer (e.g., water), an extrusion modular die containing a heating zone, and a die assembly. Extruders generally comprise a loading auger, knife, and auger (s). The loading auger is used to transport wet starch-containing precursor to the extruder. The knife is used to cut the rope pregelatinized partially hydrolyzed starch into small tablets so that they can be crushed. The screw (s) help mix the wet starch-containing precursor, transport the wet starch-containing precursor through an extruder, and provide mechanical shear. The extruder may be single screw or twin screw, as will be understood by a person of ordinary skill in the art. See, for example, Leszek Moscicki, Extrusion-Cooking Techniques, WILEY-VCH Verlag & Co. KGaA, 2011.

[0052] In single screw extruders, the screw typically comprises a loading zone with deep channels for transporting the solid phase from the opening of the loading device and compressing it, a compression zone in which the screw channels become gradually less deep and the polymer melts, and a metering zone with shallow channels that moves molten polymer into the head. Some screws are configured to add mixing devices (for example, pins extending from the screw).

[0053] Twin screw extruders typically have two screws that rotate either in the same direction (ie, rotation in one direction) or in opposite directions (ie, opposite rotation). Two augers can rotate with non-engaging or fully engaging screws. If, in the case of single-screw extruders, the feed material fills the entire working channel of the extruder, in the case of twin-screw extruders, only part of the working channel is filled, so that the loading or inlet openings below can be used to add some ingredients.

[0054] The head in the assembly typically comprises a plate, gasket, and head of a worm press. When extruding materials, this process can be either continuous, while the material is extruded of an indefinite length, or semi-continuous, while the material is extruded in parts. Extruded materials may be hot or cold.

[0055] The present invention provides a method for producing pregelatinized partially hydrolyzed starch in an extruder. You can use any suitable extruder, such as a single screw extruder (for example, an Advantage 50 extruder, which is available from American International, located in Beloit South, Illinois) or a twin-screw extruder (for example, a Wenger TX52 extruder, which is available from Wenger located in in Sabet, Kansas).

[0056] As described herein, non-gelatinized starch is an acid in the form of a weak acid that does not substantially form chelates with calcium ions and / or a strong acid in a small amount and water is mixed and fed to an extruder. In some embodiments, additional water can be added to the extruder. Although the combination of heating elements and mechanical shear in an extruder results in the melting and gelatinization of starch, a weak acid partially hydrolyzes the starch to the desired molecular weight, an indicator of which is the desired viscosity, as described herein. The conditions in the extruder, due to mechanical energy, will also cause the destruction of starch molecules, which in part produces the same effect as the acid modification. It is believed that since, according to some embodiments of the invention, the conditions in the extruder (for example, high temperature and high reaction pressure) contribute to such a chemical reaction, weak acid and / or low amounts of strong acid can be used. Thus, the method of the invention improves the efficiency of acid modification of starch.

[0057] The main screw (s) can be operated at any suitable speed so as to provide the required mixing and mechanical shear. For example, according to some embodiments of the invention, the main auger can operate at a speed of about 350 rpm (± about 100 rpm). The loading auger can operate at any suitable speed to provide the desired feed rate. For example, according to some embodiments of the invention, the loading auger can operate at a speed of about 14 rpm (± about 5 rpm).

[0058] The knife may operate at any suitable speed. For example, according to various embodiments of the invention, the knife can operate at a speed of from about 400 rpm to about 1000 rpm, for example, from about 400 rpm to about 900 rpm, from about 400 rpm to about 800 rpm / min, from about 400 rpm to about 700 rpm, from about 400 rpm to about 600 rpm, from about 400 rpm to about 500 rpm, from about 500 rpm to about 1000 rpm, from about 500 rpm to about 900 rpm, from about 500 rpm to about 800 rpm, from about 500 rpm to about 700 rpm, from about 500 rpm n to about 600 rpm, from about 600 rpm to about 1000 rpm, from about 600 rpm to about 900 rpm, from about 600 rpm to about 800 rpm, from about 600 rpm to about 700 rpm, from about 700 rpm to about 1000 rpm, from about 700 rpm to about 900 rpm, from about 700 rpm to about 800 rpm, from from about 800 rpm to about 1000 rpm, from about 800 rpm to about 900 rpm, or from about 900 rpm to about 1000 rpm.

[0059] Wet starch can be gelled and modified with acid in a die extruder at any suitable temperature so that the wet starch becomes sufficiently gelled without burning materials. For example, wet starch can be gelled and acid-modified in a head extruder at a temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF), for example, according to various embodiments of the invention, from about 150 ºC to about 205 ºC ( about 400 ºF), from about 150 ºC to about 199 ºC (about 390 ºF), from about 150 ºC to about 193 ºC (about 380 ºF), from about 150 ºC to about 188 ºC (about 370 ºF), from about 150 ºC to about 182 ºC (about 360 ºF), from about 154 ºC (about 310 ºF) to about 210 ºC, from about 154 ºC to about 205 ºC (about 400 ºF), from about 154 ºC to about 199 ºC, from about 154 ºC to about 193 ºC, from about 154 ºC to about 188 ºC, from about 154 ºC to about 182 ºC, from about 160 ºC (about 320 ºF) to about 210 ºC, from about 160 ºC to about 205 ºC (about 400 ºF), from about 160 ºC to about 199 ºC, from about 160 ºC to about 193 ºC, from about 160 ºC to about 188 ºC , from about 160 ºC to about 182 ºC, from about 166 ºC (about 330 ºF) to about 210 ºC, from about 166 ºC to about 205 ºC, from about 166 ºC to about 199 ºC, from about 166 ºC to about 193 ºC from about 166 ºC to about 188 ºC, from about 166 ºC to about 182 ºC, from about 171 ºC (about 340 ºF) to about 210 ºC, from about 171 ºC to about 205 ºC, from about 171 ºC to about 199 ºC, from about 171 ºC to about 193 ºC, from about 171 ºC to about 188 ºC, from about 171 ºC to about 182 ºC, from about 177 ºC (about 350 ºF) to about 210 ºC, from about 177 ºC to about 205 ºC, from from about 177 ° C to about 199 ° C, from about 177 ° C to about 193 ° C, from about 177 ° C to about 188 ° C, or from about 177 ° C to about 182 ° C. Although the extruder head may have any sufficient temperature as described herein, the head temperature generally exceeds the melting temperature of starch crystals.

[0060] The degree of gelation may have any suitable value, for example, at least about 70% or more, for example at least about 75%, at least about 80%, at least about 85%, at least about 90 %, at least about 95%, at least about 97%, at least about 99%, or complete (100%) gelation may occur. In the case of manufacturing a wall plate, as described below, starch with such lower degrees of gelatinization can be added to the stucco suspension, for example, additional gelatinization (for example, up to 100%) takes place in a kiln.

[0061] The pressure in the extruder may be at any suitable level so as to provide suitable conditions for gelatinization and acid modification. The pressure inside the extruder is determined by the extruded raw material, moisture content, head temperature and screw speed, which will be taken into account by a person of ordinary skill in the art. For example, the pressure in the extruder can be at least about 2000 psi (about 13800 kPa), for example at least about 2250 psi (about 15500 kPa), at least about 2500 psi (about 17200 kPa), at least about 2750 psi (about 19,000 kPa), at least about 3,000 psi (about 20,700 kPa), at least about 3,500 psi (about 24,100 kPa), at least about 4,000 psi (about 27,600 kPa), or at least about 4,500 psi ( approximately 31,000 kPa). In some embodiments, the pressure may be from about 2000 psi (about 13800 kPa) to about 5000 psi (about 34500 kPa), for example, from about 2000 psi (about 13800 kPa) to about 4500 psi (about 31000 kPa), from about 2000 psi (approximately 13800 kPa) to approximately 4000 psi (approximately 27600 kPa), from approximately 2000 psi (approximately 13800 kPa) to approximately 3500 psi (approximately 24100 kPa), from approximately 2000 psi (approximately 13800 kPa) to approximately 3000 psi ( about 20,700 kPa), from about 2,000 psi (about 13,800 kPa) to about 2,500 psi (about 17,200 kPa), from about 2,500 psi (about 17,200 kPa) to approximately 5000 psi (about 34500 kPa), from about 2500 psi (about 17200 kPa) to about 4500 psi (about 31000 kPa), from about 2500 psi (about 17200 kPa) to about 4000 psi (about 27600 kPa), from about 2500 psi (about 17,200 kPa) to about 3,500 psi (about 24,100 kPa), from about 2,500 psi (about 17,200 kPa) to about 3,000 psi (about 20,700 kPa), from about 3,000 psi (about 20,700 kPa) to about 5,000 psi (about 34,500 kPa), from about 3,000 psi (about 20,700 kPa) to about 4,500 psi (about 31,000 kPa), from about 3,000 psi (about 20,700 kPa), to about 4,000 psi (about 27,600 kPa), from about 3,000 psi (about 20,700 Pa) to about 3500 psi (about 24100 kPa), from about 3500 psi (about 24100 kPa) to about 5000 psi (about 34500 kPa), from about 4000 psi (about 27600 kPa) to about 5000 psi (about 34500 kPa), from about 4,000 psi (about 27,600 kPa) to about 4,500 psi (about 31,000 kPa); or from about 4,500 psi (about 31,000 kPa) to about 5,000 psi (about 34,500 kPa).

[0062] Surprisingly and unexpectedly, it was found that the inventive method for producing pregelatinized partially hydrolyzed starch in one stage in an extruder is significantly faster than pregelatinization and acid modification of starch in two stages, carried out sequentially. Significantly larger amounts of pregelatinized partially hydrolyzed starch can be obtained using the method of the invention than starch obtained in any other way. Higher production volumes and faster production rates are due to the high reaction rate at high temperature and / or high pressure. In some embodiments, pregelatinization and acid modification occur in less than about 5 minutes, for example, less than about 4 minutes, for example, less than about 3 minutes, less than about 2 minutes, less than about 90 seconds, less than about 75 seconds, less than about 1 minute less than about 45 seconds, less than about 30 seconds, less than about 25 seconds, less than about 20 seconds, less than about 15 seconds, or less than about 10 seconds. In addition, according to some embodiments of the invention, pregelatinization and acid modification occur in the extruder at a rate limited by any two of the above values. For example, the speed of pre-gelatinization and acid modification may be from about 10 seconds to 5 minutes, for example, from about 10 seconds to about 4 minutes, from about 10 seconds to about 3 minutes, from about 10 seconds to about 2 minutes, from about 10 seconds up to about 90 seconds, from about 10 seconds to about 75 seconds, from about 10 seconds to about 1 minute, from about 10 seconds to about 45 seconds, from about 10 seconds to about 30 seconds, from about 10 seconds to about 25 seconds, from about 10 seconds to about 20 seconds or from approx angles 10 seconds to about 15 seconds.

[0063] The process of the invention for the preparation of pregelatinized partially hydrolyzed starch may be a continuous process proceeding at any sufficient speed. In some embodiments, the starch is subjected to gelatinization and acid modification at an extruder output rate of at least about 100 kg / h, for example at least about 150 kg / h, at least about 200 kg / h, at least at least about 250 kg / h, at least about 300 kg / h, at least about 350 kg / h, at least about 400 kg / h, at least about 450 kg / h, 500 kg / h, at least at least about 550 kg / h, for example at least about 600 kg / h with at least about 650 kg / h, at least about 700 kg / h, at least about 750 kg / h, at least about 800 kg / h, at least about 850 kg / h, at least about 900 kg / h, at least about 950 kg / h, at least about 1000 kg / h, at least about 1050 kg / h, at least about 1100 kg / h, at least about 1150 kg / h at least about 1200 kg / h, at least about 1250 kg / h, at least about 1300 kg / h, at least about 1350 kg / h, at least approximately about 1400 kg / h, at least about 1450 kg / h or at least about 1500 kg / h. In addition, according to some embodiments of the invention, the speed of production in the extruder may be limited by any two of the above values. For example, the output rate may be from about 100 kg / h to about 1500 kg / h (for example, from about 100 kg / h to about 1500 kg / h, from about 100 kg / h to 1000 kg / h, from about 250 kg / h to about 1500 kg / h, from about 250 kg / h to about 1000 kg / h, from about 600 kg / h to about 1250 kg / h, from about 650 kg / h to about 1200 kg / h, about 700 kg / h to about 1100 kg / h, from about 750 kg / h to about 1000 kg / h, etc.).

[0064] The inventors have found that, according to some embodiments of the invention, the conditions in the extruder (for example, high temperature and high pressure) especially contribute to the effective and sufficient pre-gelatinization and acid modification of starch in a single step. When mixing wet starch in an extruder, it creates a very high friction, which, therefore, leads to the release of heat. Shear forces occur under the action of the screw in the extruder, since the distance between the screw and the chamber in the extruder is very small. Specific mechanical energy (SME) describes the mechanical energy of an object per unit mass. SME will be dependent on moisture content. Higher moisture content (for example, for flowability) will result in lower viscosity and low friction, and thus lower SME. With more moisture, SME will be less important due to its low viscosity and low friction. The moisture content of the wet starch-containing precursor according to the invention described herein provides an effective SME.

[0065] In an extruder, due to the conditions provided by the embodiments of the present invention described herein, starch is gelled with high efficiency. Not wishing to be bound by any particular theory, it is believed that good mixing in an extruder according to some embodiments of the present invention requires less water to carry out the reaction in the extruder. Very low moisture content contributes to a high concentration of the reagent, which can accelerate the speed of a chemical reaction. The high temperature of the extruder also significantly increases the reaction rate. When the starch leaves the extruder, a reaction has already occurred, so that the starch is pre-gelatinized and partially hydrolyzed.

[0066] In a typical acid modification, starch is added to a strong acid solution. This conventional method uses significantly more water and acid than using the surprising and unexpected method, which involves simultaneous, rather than sequential, processes of gelatinization and acid modification of starch in a single step in an extruder, as described herein. The usual acid modification takes several hours. After the reaction has occurred, the acid must be neutralized, cleaned and washed. These neutralization and purification steps are time consuming and expensive.

[0067] Prior to the surprising and unexpected discovery made by the inventors, it was considered undesirable for a conventional acid modification to use a weak acid, which essentially does not form chelates with calcium ions, or a strong acid in a small amount. This is due to the fact that in the conventional method, the weaker the acid or the less the amount of strong acid, the longer the acid modification takes. Thus, in the usual acid modification, it was desirable to use strong acid (for example, with pKa below about -1.7) in large quantities. Surprisingly and unexpectedly, when preparing pregelatinized partially hydrolyzed starch in an extruder according to embodiments of the present invention using a weak acid or strong acid in a small amount, as described herein, neutralization and purification steps are not necessary due to slightly acidic conditions and less interfering effect on gypsum crystallization, respectively. In some embodiments, the acid may still be present in the pregelatinized partially hydrolyzed starch.

Properties of starch and advantages of using starch in a gypsum board

[0068] The starch obtained in an extruder according to embodiments of the present invention may be any pre-gelatinized partially hydrolyzed starch. According to some embodiments of the invention, starch having various properties can be obtained, if necessary (for example, viscosity in the middle range, solubility in cold water, viscosity in cold water, etc.), as described herein.

[0069] The pre-gelatinized partially hydrolyzed starches obtained in an extruder according to embodiments of the present invention may be suitable for use in a gypsum board. When used in a gypsum board, for example, pregelatinization and acid modification are valuable, for example, for imparting strength by providing the desired viscosity (and therefore molecular weight range) according to embodiments of the present invention as described herein. In the proposed method for producing a wall plate described herein, the degree of gelatinization of starch added to the stucco suspension may be at least about 70%, for example at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, or 100% (i.e., starch is completely gelled).

[0070] In addition, according to embodiments of the present invention, feeding the extruder wet starch containing a weak acid that does not substantially form chelates with calcium ions, as described herein, allows the starch to be hydrolyzed in such a way as to provide the desired viscosity, which accordingly, indicates the achievement of the desired range of molecular weight. Viscosity, therefore, is an indicator of the molecular weight of the pre-gelatinized partially hydrolyzed starch, as will be understood by one of ordinary skill in the art.

[0071] According to some embodiments of the invention, it is possible to obtain pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention having any suitable viscosity. According to some embodiments of the invention, said viscosity is characterized as “mid-range” viscosity (ie, viscosity in the range of about 20 centipoise to about 700 centipoise) when pregelatinized partially hydrolyzed starch is subjected to conditions according to the VMA method using pregelatinized partially hydrolyzed starch in water in an amount of 15% by weight relative to the total weight of the pre-gelatinized partially hydrolyzed starch and water. Thus, the VMA method is used to determine whether pregelatinized partially hydrolyzed starch has a mid-range viscosity characteristic when exposed to conditions according to the VMA method. This does not mean that pregelatinized partially hydrolyzed starch should be added to the gypsum slurry under such conditions. Rather, when pregelatinized partially hydrolyzed starch is added to the suspension, it can be in wet (at various concentrations of starch in water) or dry forms and need not be completely gelled, as described herein, or otherwise be in the conditions described in the method VMA

[0072] In some embodiments, the viscosity in the middle range of pregelatinized starch can be from about 20 centipoise to about 700 centipoise, for example, from about 20 centipoise to about 500 centipoise, from about 30 centipoise to about 200 centipoise, or from about 100 centipoise to approximately 700 centipoise. According to embodiments of the present invention, the viscosity of pregelatinized starch when tested according to the VMA method can have the values, for example, listed below in Tables 1A, 1B and 1C. In these tables, “X” represents the range “from about [the corresponding value in the top row] to about [the corresponding value in the very left column]”. The indicated values are the viscosity of pregelatinized starch in centipoises. For simplicity of presentation, it should be understood that each value represents a “roughly” indicated value. For example, the first “X” in Table 1A is in the range of “from about 20 centipoise to about 25 centipoise”.

Table 1A

Initial viscosity range (centipoise) Final viscosity range (centipoise) twenty 25 thirty 35 40 45 fifty 55 60 65 70 75 25 X thirty X X 35 X X X 40 X X X X 45 X X X X X fifty X X X X X X 55 X X X X X X X 60 X X X X X X X X 65 X X X X X X X X X 70 X X X X X X X X X X 75 X X X X X X X X X X X one hundred X X X X X X X X X X X X 125 X X X X X X X X X X X X 150 X X X X X X X X X X X X 175 X X X X X X X X X X X X 200 X X X X X X X X X X X X 225 X X X X X X X X X X X X 250 X X X X X X X X X X X X 275 X X X X X X X X X X X X 300 X X X X X X X X X X X X 325 X X X X X X X X X X X X 350 X X X X X X X X X X X X 375 X X X X X X X X X X X X 400 X X X X X X X X X X X X 425 X X X X X X X X X X X X 450 X X X X X X X X X X X X 475 X X X X X X X X X X X X 500 X X X X X X X X X X X X 525 X X X X X X X X X X X X 550 X X X X X X X X X X X X 575 X X X X X X X X X X X X 600 X X X X X X X X X X X X 625 X X X X X X X X X X X X 650 X X X X X X X X X X X X 675 X X X X X X X X X X X X 700 X X X X X X X X X X X X

Table 1B

Initial viscosity range (centipoise) Final viscosity range (centipoise) one hundred 125 150 175 200 225 250 275 300 325 350 375 125 X 150 X X 175 X X X 200 X X X X 225 X X X X X 250 X X X X X X 275 X X X X X X X 300 X X X X X X X X 325 X X X X X X X X X 350 X X X X X X X X X X 375 X X X X X X X X X X X 400 X X X X X X X X X X X X 425 X X X X X X X X X X X X 450 X X X X X X X X X X X X 475 X X X X X X X X X X X X 500 X X X X X X X X X X X X 525 X X X X X X X X X X X X 550 X X X X X X X X X X X X 575 X X X X X X X X X X X X 600 X X X X X X X X X X X X 625 X X X X X X X X X X X X 650 X X X X X X X X X X X X 675 X X X X X X X X X X X X 700 X X X X X X X X X X X X

Table 1C

Initial viscosity range (centipoise) Final viscosity range (centipoise) 400 425 450 475 500 525 550 575 600 625 650 675 425 X 450 X X 475 X X X 500 X X X X 525 X X X X X 550 X X X X X X 575 X X X X X X X 600 X X X X X X X X 625 X X X X X X X X X 650 X X X X X X X X X X 675 X X X X X X X X X X X 700 X X X X X X X X X X X X

[0073] Thus, the viscosity of the pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention may lie in the range between any of the end points listed above in Tables 1A, 1B or 1C, and includes the indicated points. Alternatively, in some embodiments, the pregelatinized partially hydrolyzed starch has a viscosity (10% solids, 93 ° C) of from about 5 Brabender units (BU) to about 33 BU, measured according to the Brabender method described herein, for example, from about 10 BU to about 30 BU, from about 12 BU to about 25 BU, or from about 15 BU to about 20 BU.

[0074] According to some embodiments of the invention, the pregelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention can provide significant advantages in terms of the strength of the product (eg, wall plate) in which they are used. Since starch contains glucose monomers containing three hydroxyl groups, starch provides many sites for the formation of hydrogen bonds with gypsum crystals. Not wishing to be bound by any particular theory, it is believed that the molecular size of the pre-gelatinized partially hydrolyzed starch obtained according to embodiments of the present invention provides optimal mobility of starch molecules and allows starch molecules to group around gypsum crystals, which promotes good binding of starch to gypsum crystals and strengthens the formed crystalline gypsum matrix, for example, through the formation of hydrogen bonds.

[0075] Conventional pregelatinized starches obtained according to a different method rather than the method described herein, for example, having viscosities outside the middle range that will have either longer chains and higher molecular weight (viscosity that is too high) or shorter chains and lower molecular weights (viscosity that is too low), respectively, do not provide the same combination of advantages. In addition, it is believed that from the point of view of starch efficiency, when starch molecules bind sufficiently to gypsum crystals, the additional amount of starch does not add a significant advantage, since the crystals are already bound, so there are no additional areas in gypsum crystals with which starch can stick together or bind. Accordingly, due to the optimal binding of the gypsum crystals and the pre-gelatinized partially hydrolyzed starch molecules obtained according to the embodiments of the present invention, the strength of the crystalline gypsum matrix is increased, and less starch is required to provide such strength compared to conventional starches. The inventors have found that molecules of dissolved starch, for example, with a viscosity in the middle range (which means the molecular weight of starch in the middle range) provide optimal mobility of starch molecules, which allows starch molecules to group with gypsum crystals and promotes good hydrogen bonding of starch and gypsum and strength core according to some embodiments of the invention.

[0076] According to some embodiments of the invention, the pre-gelatinized partially hydrolyzed starch obtained according to some embodiments of the invention also provides benefits in terms of water consumption. The addition of conventional pregelatinized starch to the gypsum slurry requires the addition of additional water to the gypsum slurry to maintain the desired degree of fluidity of the suspension. This is due to the fact that ordinary pregelatinized starch increases the viscosity and reduces the fluidity of the gypsum slurry. Thus, the use of pregelatinized starch in conventional systems would increase water consumption in such a way that even a larger excess of water would be required in the gypsum slurry.

[0077] Surprisingly and unexpectedly, pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention, in particular with a desired viscosity in the middle range, requires less water, so that the effect on water consumption in gypsum slurry is reduced, especially compared to conventional starches. In addition, due to the effectiveness of the pre-gelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention so that less starch can be used, the positive effect on water consumption can be even more significant according to some embodiments of the present invention. This lower water consumption provides significant production efficiency. For example, excess water requires a supply of energy for drying. When drying, the speed of the production line should be reduced. Thus, by reducing the amount of water in the gypsum slurry, it is possible to spend less energy and reduce costs, as well as provide greater productivity. According to some embodiments of the invention, the increase in water consumption of gypsum slurry is less than the increase in water consumption required with other starches, such as pregelatinized starches with a viscosity above 700 centipoise (for example, about 773 centipoise), for example, obtained in another way.

[0078] To obtain pregelatinized partially hydrolyzed starch, any suitable non-pregelatinized starch can be selected provided that it is sufficient for pregelatinization and acid modification in the extruder. As used herein, “starch” refers to a composition comprising a starch component. Essentially, the starch may be 100% pure starch or may contain other components, for example, components usually present in flour, such as protein and fiber, provided that the starch component is at least about 75% by weight relative to the mass of starch composition. The starch may be in the form of flour (eg, corn flour) containing starch, for example, flour containing at least about 75% starch by weight relative to the weight of the flour, for example at least about 80%, at least about 85%, at least about 90%, at least about 95%, and the like). By way of example, and not limitation, starch may be in the form of cornmeal containing starch.

[0079] According to some embodiments of the invention, pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention having the desired solubility in cold water can be obtained. Conventional pregelatinization methods include the preparation of starch soluble in cold water, and generally require the starch to be cooked in excess water. However, these conventional methods are not effective. Extrusion according to embodiments of the present invention, providing a combination of heating and mechanical shear, surprisingly and unexpectedly is an energy-saving method that can be used to produce pre-gelatinized partially hydrolyzed starch having a low moisture content when soluble in cold water in a one-step process. Cold water solubility is defined as the presence of any degree of solubility in water at room temperature (approximately 25 ° C). It has been found that starches exhibiting solubility in cold water can provide significant advantages in terms of the strength of gypsum products (e.g., wallboard). The cold water soluble starches of the present invention have a cold water solubility of greater than about 30% and, when added to the captured gypsum core, can increase the strength of the gypsum core. The solubility of pregelatinized starch in water is defined as the amount of starch that dissolves in room temperature water divided by the total amount of starch.

[0080] According to some embodiments of the invention, the cold solubility of the pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention is from about 30% to about 100%. According to other embodiments of the invention, the solubility in cold water of the extruded pregelatinized partially hydrolyzed starch is from about 50% to about 100%. According to embodiments of the present invention, the cold solubility of the extruded pregelatinized partially hydrolyzed starch may have the meanings, for example, shown in Table 2. In the indicated table, “X” is a range of “from about [corresponding value in the top row] to about [corresponding value in leftmost column]. ” The indicated values are the cold solubility of the extruded pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention (table 2). For ease of presentation, it should be understood that each value represents a “roughly” indicated value. For example, the first “X” in table 2 is in the range of “from about 30% to about 35%.” The ranges given in the table lie between the start and end points and include the indicated points.

table 2

The initial value of the range of solubility in cold water (%) The final value of the range of solubility in cold water (%) thirty 35 40 45 fifty 55 60 65 70 75 80 85 90 95 35 X 40 X X 45 X X X fifty X X X X 55 X X X X X 60 X X X X X X 65 X X X X X X X 70 X X X X X X X X 75 X X X X X X X X X 80 X X X X X X X X X X 85 X X X X X X X X X X X 90 X X X X X X X X X X X X 95 X X X X X X X X X X X X X one hundred X X X X X X X X X X X X X X

[0081] Without wishing to be bound by any particular theory, it is believed that the combination of mechanical and thermal energy during the extrusion process is responsible for the cold solubility of pre-gelatinized partially hydrolyzed starch obtained according to embodiments of the present invention. It is believed that when starch is extruded, the hydrogen bonds between starch molecules are broken. When the extruded starch is dissolved in water, starch forms hydrogen bonds with water molecules. After the pre-gelatinization process, the molecules of the extruded pre-gelatinized partially hydrolyzed starch can form hydrogen bonds with gypsum crystals, thereby giving the gypsum product greater strength. Accordingly, since cold water soluble starches improve the strength of the gypsum wallboard, less starch is required than conventional starches.

[0082] According to some embodiments of the invention, the viscosity in cold water (10% solids, 25 ºC) of pre-gelatinized partially hydrolyzed starch, measured according to the Brabender method described herein, is from about 10 BU to about 120 BU, for example, from about 20 BU to about 110 BU, from about 30 BU to about 100 BU, from about 40 BU to about 90 BU, from about 50 BU to about 80 BU, or from about 60 BU to about 70 BU.

The use of starch obtained according to the proposed method in the manufacture of plates

[0083] According to some embodiments of the invention, a slab (eg, a gypsum wall slab) can be made by preparing pregelatinized partially hydrolyzed starch by mixing at least water, ungelatinized starch and acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% wt., while the acid is selected from: a weak acid, which essentially does not form chelates with calcium ions, a strong acid in an amount of about 0.01% of the mass. or less by weight relative to the mass of starch or any combination thereof.

[0084] The wet starch precursor is then fed to an extruder in which the head temperature is from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF), where the wet starch is subjected to gelatinization and acid modification so that it at least partially hydrolyzed. The pregelatinized partially hydrolyzed starch can then be mixed with at least water and gypsum to form a slurry, which can then be placed between the first cladding sheet and the second cladding sheet to form a wet precast structure. Further, the wet prefabricated structure can be cut to obtain a plate, which is then dried. The grasped gypsum core of the plate preferably has a compressive strength greater than that of a gypsum core made using starch made according to another method.

[0085] It is surprising and unexpected that the pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention can be included in the suspension in a relatively low amount (solid phase / calculated on the solid phase) and still provide a significant increase in the strength of the board. Accordingly, the pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention can be included in the gypsum slurry in an amount of from about 0.1% to about 10% by weight based on the weight of the plaster, for example, from about 0.5% to approximately 10%.

[0086] It was found that an increase in the amount of pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention in suspension above the indicated limits does not improve strength so effectively as strength levels may partly stop growing when even more starch is added according to some embodiments of the invention . However, if necessary, higher amounts of starch can be used, especially when diminishing returns on strength are allowed.

[0087] According to embodiments of the present invention, pregelatinized partially hydrolyzed starch can be added to the gypsum slurry in an amount, for example, shown in Tables 3A and 3B below. In the indicated table, “X” represents a range of “from about [corresponding value in the top row] to about [corresponding value in the leftmost column]”. The indicated values represent the amount of starch as a percentage by weight relative to the weight of the plaster. For ease of presentation, it should be understood that each value represents a “roughly” indicated value. For example, the first “X” is in the range of “from about 0.1% starch by weight relative to the weight of the plaster to about 0.25% starch by weight relative to the weight of the plaster.”

Table 3A

0.1 0.25 0.5 0.75 1,0 1.25 1,5 1.75 2.0 2.25 2,5 2.75 3.0 3,5 0.25 X 0.5 X X 0.75 X X X 1,0 X X X X 1.25 X X X X X 1,5 X X X X X X 1.75 X X X X X X X 2.0 X X X X X X X X 2.25 X X X X X X X X X 2,5 X X X X X X X X X X 2.75 X X X X X X X X X X X 3.0 X X X X X X X X X X X X 3,5 X X X X X X X X X X X X X 4.0 X X X X X X X X X X X X X X 4,5 X X X X X X X X X X X X X X 5,0 X X X X X X X X X X X X X X 5.5 X X X X X X X X X X X X X X 6.0 X X X X X X X X X X X X X X 6.5 X X X X X X X X X X X X X X 7.0 X X X X X X X X X X X X X X 7.5 X X X X X X X X X X X X X X 8.0 X X X X X X X X X X X X X X 8.5 X X X X X X X X X X X X X X 9.0 X X X X X X X X X X X X X X 9.5 X X X X X X X X X X X X X X 10.0 X X X X X X X X X X X X X X

Table 3B

4.0 4,5 5,0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 4,5 X 5,0 X X 5.5 X X X 6.0 X X X X 6.5 X X X X X 7.0 X X X X X X 7.5 X X X X X X X 8.0 X X X X X X X X 8.5 X X X X X X X X X 9.0 X X X X X X X X X X 9.5 X X X X X X X X X X X 10.0 X X X X X X X X X X X X

[0088] Thus, the amount of pre-gelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention added to the suspension may lie in the range between any of the end points listed in Tables 3A or 3B above and includes the indicated points.

[0089] According to some embodiments of the invention, the pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention can be added to the suspension in combination with other starches for various applications. For example, in the case of the gypsum wallboard described below, the pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention can be combined with other starches to enhance both core strength and paper-core bond, in particular if some increase in water consumption is allowed.

[0090] Thus, according to some embodiments of the present invention, the gypsum slurry may include one or more pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention, as well as one or more other types of starches. Other starches may include, for example, pregelatinized starches with a viscosity below 20 centipoise and / or above 700 centipoise. One example is pregelatinized corn starch (for example, with a viscosity above 700 centipoise, for example, about 773 centipoise). Other starches may also be in the form of, for example, non-gelatinized starches, such as acid modified starches, and also alkylated starches, for example, ethylated starches that are not gelled, and the like. Before adding to the gypsum slurry, the combination of starches can be premixed (for example, in a dry mixture, optionally with other components such as plaster, etc., or in a wet mixture with other wet ingredients) or they can be added to the gypsum suspension one at a time once or in any of their variations. Any suitable proportion of pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention and other starch may be used.

[0091] For example, the starchiness of pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention, as a percentage of the total starch added to the gypsum slurry, can be, for example, at least about 10% by weight, for example at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% at least at least about 95%, at least about 99%, at least about 100%, or lie in any range between the indicated values. According to some embodiments of the invention, the ratio of pregelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention to another starch may be about 25:75, about 30:70, about 35:65, about 50:50, about 65:35, about 70 : 30, about 75:25, etc.

[0092] According to some embodiments of the invention, along with the starch component, the suspension is prepared in such a way that it includes water, plaster, a foaming agent (sometimes referred to simply as “foam”) and other additives, if necessary. Surprisingly and unexpectedly, according to some embodiments of the invention, in particular, those showing viscosity in the middle range, it was found that the amount of water that must be added to maintain the fluidity of the suspension at the same level that would be without the use of pre-gelatinized partially hydrolyzed starch obtained in the extruder according to the variants of implementation of the present invention, less than the increase in the amount of water required when using starch obtained according to rugomu method. The plaster may be in the form of calcium sulfate alpha hemihydrate, calcium sulfate beta hemihydrate and / or calcium sulfate anhydrite. The plaster may be fibrous or non-fibrous. A foaming agent can be included to form the distribution of air pores within the continuous crystalline matrix of the captured gypsum. In some embodiments, the foaming agent contains a major mass fraction of an unstable component and a small mass fraction of a stable component (for example, by combining an unstable component and a mixture of a stable component / unstable component). Such a mass ratio of the ratio of the unstable component to the stable component is effective for forming the distribution of air pores within the captured gypsum core. See, for example, U.S. Patents 5,643,510; 6342284; and 6632550.

[0093] It has been found that a suitable pore distribution and wall thickness (independently) can be effective in terms of increasing strength, especially lower density boards (for example, below about 35 lb / cubic foot (about 561 kg / m ³ ) ) See, for example, US 2007/0048490 and US 2008/0090068. The pores formed by the evaporation of water, the diameter of which is generally about 5 μm or less, also contribute to the overall distribution of the pores along with the above-mentioned air pores (foam). In some embodiments, the volumetric ratio of pores with a size greater than about 5 microns to pores with a size of about 5 microns or less is from about 0.5: 1 to about 9: 1, for example, from about 0.7: 1 to about 9: 1, from about 0.8: 1 to about 9: 1, from about 1.4: 1 to about 9: 1, from about 1.8: 1 to about 9: 1, from about 2.3: 1 to about 9: 1, from about 0.7: 1 to about 6: 1, from about 1.4: 1 to about 6: 1, from about 1.8: 1 to about 6: 1, from about 0.7: 1 to about 4: 1, from about 1.4: 1 to about 4: 1, from about 1.8: 1 to about 4: 1, from approximately 0.5: 1 to about 2.3: 1, from about 0.7: 1 to about 2.3: 1, from about 0.8: 1 to about 2.3: 1, from about 1.4: 1 to about 2.3: 1, from about 1.8: 1 to about 2.3: 1, and the like. In some embodiments, the foaming agent is present in the suspension, for example, in an amount of less than about 0.5% by weight relative to the weight of the plaster, for example, from about 0.01% to about 0.5%, from about 0.01% to about 0.4%, from about 0.01% to about 0.3%, from about 0.01% to about 0.2%, from about 0.01% to about 0.1%, from about 0.02% to about 0.4%, from about 0.02% to about 0.3%, from about 0.02% to about 0.2%, and the like, by weight relative to the weight of the plaster.

[0094] Additives such as a set accelerator (for example, a gypsum set accelerator, a heat-resistant set accelerator, a stabilized set accelerator for various climatic conditions) and a set retarder are well known and can be used according to some embodiments of the invention. See, for example, US Pat. Nos. 3,573,947 and 6,409,925. According to some embodiments, when a setting accelerator and / or set retarder is included in the invention, the amount of each specified set accelerator and / or set retarder in a gypsum slurry based on solids may be, for example, from about 0% to about 10% by weight relative to the weight of the plaster (for example, from about 0.1% to about 10%), for example, from about 0% to about 5% by weight relative to the weight of the plaster (for example, from about 0.1 % to example about 5%). Other additives can be included in the present invention, if necessary, for example, to give strength, which will allow to obtain a product with a lower mass and sufficient strength, to avoid permanent deformation, to ensure the strength of the raw material, for example, when placing the product on a conveyor moving along the production line, ensuring fire resistance, ensuring water resistance, etc.

[0095] For example, in some embodiments, the suspension may optionally contain at least one dispersant to increase fluidity. Like pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention and other ingredients, dispersants can be included in the suspension to form a core in dry form along with other dry ingredients and / or in liquid form along with other liquid ingredients. Examples of dispersants include naphthalenesulfonates, such as polynaphthalenesulfonate and its salts (polynaphthalenesulfonates) and derivatives, which are condensation products of naphthalenesulfonates and formaldehyde; as well as polycarboxylate dispersants, such as polycarboxylic esters, for example, dispersants PCE211, PCE111, 1641, 1641F or PCE type 2641, for example, dispersants (BASF) MELFLUX 2641F, MELFLUX 2651F, MELFLUX 1641F, MELFLUX 2500l and COEX, at Coatex, Inc .; and / or lignosulfonates or sulfonated lignin. Lignosulfonates are water-soluble anionic polyelectrolytes-polymers, by-products of the production of wood pulp using sulphite cooking. One example of lignin that can be used in the practical implementation of the principles of the variants of the present invention is Marasperse C-21, which can be purchased from Reed Lignin Inc.

[0096] In general, lower molecular weight dispersants are preferred. Lower molecular weight naphthalenesulfonate dispersants are preferred since they are usually characterized by lower water consumption than higher molecular weight dispersants with a higher viscosity. Thus, molecular weights of from about 3,000 to about 10,000 (e.g., from about 8,000 to about 10,000) are preferred. As another example, according to some embodiments of the invention, in the case of dispersants of the type PCE211, the molecular weight can be from about 20,000 to about 60,000, with said dispersants exhibiting less retardation than dispersants with a molecular weight above 60,000.

[0097] One example of naphthalenesulfonate is DILOFLO, which can be purchased from GEO Specialty Chemicals. DILOFLO is a 45% solution of naphthalenesulfonate in water, although other aqueous solutions are also readily available, for example, with a solids content in the range of from about 35% to about 55% by weight. Naphthalenesulfonates can be used in dry solid or powder form, such as LOMAR D, which can be obtained, for example, from GEO Specialty Chemicals. Another typical naphthalene sulfonate is DAXAD, which is available from Hampshire Chemical Corp.

[0098] When used, the dispersant may be included in any suitable amount (solid phase / solid phase), such as, for example, from about 0.1% to about 5% by weight based on the weight of the plaster, for example, from about 0, 1% to about 4%, from about 0.1% to about 3%, from about 0.2% to about 3%, from about 0.5% to about 3%, from about 0.5% to about 2, 5%, from about 0.5% to about 2%, from about 0.5% to about 1.5%, and the like.

[01] According to some embodiments of the invention, if necessary, one or more phosphate-containing compounds may also optionally be included in the suspension. For example, phosphate-containing components useful in some embodiments of the invention include water-soluble components and may be in the form of an ion, salt or acid, namely, condensed phosphoric acids, each of which contains two or more units of phosphoric acid; salts or ions of condensed phosphates, each of which contains two or more phosphate units; and monobasic salts or monovalent ions of orthophosphates, as well as a water-soluble acyclic polyphosphate salt. See, for example, US Pat. Nos. 6,342,284; 6,632,550; 6815049; and 6822033.

[01] According to some embodiments of the invention, phosphate compositions when added can increase the strength of the raw material, resistance to permanent deformation (eg, deflection), ability to maintain dimensions, and the like. Trimetaphosphate compounds can be used, including, for example, sodium trimetaphosphate, potassium trimetaphosphate, lithium trimetaphosphate and ammonium trimetaphosphate. Sodium trimetaphosphate (STMP) is preferred, although other phosphates may be suitable, including, for example, sodium tetramethaphosphate, sodium hexametaphosphate containing from about 6 to about 27 repeating phosphate units and having the molecular formula Na_{n + 2}P_nO_{3n + 1} where n = 6-27, potassium tetrapyrophosphate having the molecular formula K_fourP₂O₇, Trisodium dipotassium tripolyphosphate having the molecular formula Na₃K₂P₃O₁₀, sodium tripolyphosphate having the molecular formula Na₅P₃O₁₀, sodium tetrapyrophosphate having the molecular formula Na_fourP₂O₇, aluminum trimetaphosphate having the molecular formula Al (PO₃)₃acid sodium pyrophosphate having the molecular formula Na₂H₂P₂O₇ammonium polyphosphate containing from 1000 to 3000 repeating phosphate units and having a molecular formula (NH_four)_{n + 2}P_nO_{3n + 1}where n = 1000-3000, or polyphosphoric acid containing two or more repeating units of phosphoric acid and having the molecular formula H_{n + 2}P_nO_{3n + 1}where n is two or more.

[02] In some embodiments, phosphate in dry form or in water form can be included in the present invention (for example, from about 5% to about 20% phosphate solution, for example, about 10% solution). When included in the present invention, the phosphate may be in any suitable amount (solid phase / based on solid phase), for example, from about 0.01% to about 0.5% by weight based on the weight of the plaster, for example, from about 0 , 03% to about 0.4%, from about 0.1% to about 0.3%, or from about 0.12% to about 0.4% by weight based on the weight of the plaster.

[03] It is also possible to optionally include suitable additives in the present invention to produce a product with an established degree of fire resistance and / or a waterproof product, including, for example, siloxanes (waterproof); fiber; heat sink additives such as aluminum trihydrite (ATH), magnesium hydroxide or the like; and / or particles with a high coefficient of thermal expansion (for example, expanding to about 300% or more of the original volume when heated for about one hour at 1560 ° F (about 850 ^about C)). See, for example, a pending patent application of US Patent No. 13/400010 (filed February 17, 2012) that belongs to the same copyright holder and describes the listed and other ingredients. In some embodiments, vermiculite with a high coefficient of thermal expansion is included in the invention, although other flame retardant materials may be used. A stove of any fire-related product of the invention may have a thermal insulation index (TI) of about 17 minutes or more, for example, about 20 minutes or more, about 30 minutes or more, about 45 minutes or more, about 60 minutes or more etc.; and / or have high temperature shrinkage (at temperatures of about 1560 ° F (850 ° C)) of less than about 10% in the xy directions and expansion in the z-direction of more than about 20%. If necessary, flame retardant or waterproof additives can be included in the present invention in any suitable amount, depending, for example, on the degree of fire hazard, etc. For example, when used, the amount of flame retardant or water-resistant additives can be from about 0.5% to about 10% by weight relative to the weight of the plaster, for example, from about 1% to about 10%, from about 1% to about 8%, from about 2 % to about 10%, from about 2% to about 8% by weight relative to the weight of the plaster, etc.

[04] In some embodiments, when included in the present invention, siloxane is preferably added in the form of an emulsion. Then the suspension is molded and dried under conditions conducive to the polymerization of siloxane, to obtain a highly cross-linked silicone resin. A catalyst can be added to the gypsum slurry to aid in the polymerization of siloxane and the production of a highly crosslinked silicone resin. In some embodiments, a solvent-free poly (methylhydrosiloxane) solution sold under the name SILRES BS 94 by Wacker-Chemie GmbH (Munich, Germany) can be used as a siloxane. This product is a siloxane solution free of water or solvents. It is contemplated that in some embodiments, from about 0.3% to about 1.0% BS 94 siloxane can be used based on the weight of dry ingredients. For example, in some embodiments of the invention, it is preferable to use from about 0.4% to about 0.8% siloxane based on the weight of the dry plaster.

[05] The composition of the suspension can be obtained at any suitable ratio of water / plaster, for example, from about 0.4 to about 1.3. However, since the pre-gelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention can reduce the amount of water that needs to be added to the suspension for introducing the indicated starches compared to other starches (for example, conventional pregelatinized starches obtained according to another method), the suspension can be prepared with an input water / plaster ratio that is lower according to some embodiments of the invention than the ratio of commonly applied for other starch containing gypsum slurries, particularly at low mass / density. For example, in some embodiments, the water / plaster ratio may be from about 0.4 to about 1.1, from about 0.4 to about 0.9, from about 0.4 to about 0.85, from about 0, 45 to about 0.85, from about 0.55 to about 0.85, from about 0.55 to about 0.8, from about 0.6 to about 0.9, from about 0.6 to about 0.85 , from about 0.6 to about 0.8, and the like.

[06] Sheathing sheets can be made of any suitable material and with any bulk. A slab core made from a slurry containing pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention preferably provides sufficient slab strength even with cladding sheets with a lower base weight, such as, for example, less than 45 psi / 1000 sq. feet (about 220 g / m ² (e.g., from about 33 pounds / 1000 square feet (about 161 g / m ² ) to 45 pounds / 1000 square feet (about 220 g / m ² )), according to some embodiments of the invention even in the case of a slab with a lower weight (for example, with a density of about 35 lb / cubic foot (about 561 kg / m ³ ) or lower) However, if necessary, heavier bulk materials, for example, can be used according to some embodiments of the invention , to further strengthen the resistance to pulling nails or to improve processing, for example, Ridanna required "tactile" characteristics suitable for the end users.

[07] According to some embodiments of the invention, to enhance the strength (for example, the strength when pulling nails), especially in the case of a plate with a lower density, one or both of the sheathing sheets can be made of paper and have a bulk of, for example, at least at least about 45 pounds / 1000 sq. feet (about 220 g / m ² ) (e.g., from about 45 pounds / 1000 square feet (about 220 g / m ² ) to about 65 pounds / 1000 square feet (about 317 g / m ² ), from about 45 pounds / 1000 square feet (about 220 g / m ² ) to about 60 pounds / 1000 square feet (about 293 g / m ² ), from about 45 pounds / 1000 square feet (about 220 g / m ² ) to about 55 lbs / 1000 sq. ft (about 269 g / m ²⁾ from about 50 lbs / 1000 sq. ft (about 244 g / m ²⁾ to about 65 lbs / 1000 sq. ft (about 317 g / m ² ) of from about 50 lbs / 1000 sq. ft (about 244 g / m ²⁾ to about 60 lbs / 1000 sq. ft (about 293 g / m ^2), and the like). If necessary, according to some embodiments of the invention, one cladding sheet (for example, the “front” side of the paper during installation) may have the aforementioned higher bulk, for example, to increase the resistance to pulling nails and improve processing, while another cladding sheet (for example, The “back” sheet when installing the slab) may have a slightly lower base weight, if necessary (for example, a base weight of less than about 45 pounds / 1000 square feet (about 220 g / m ² ), for example, from about 33 pounds / 10 00 sq. Ft. (About 161 g / m ² ) to about 45 pounds / 1000 sq. Ft. (About 220 g / m ² ) or from about 33 pounds / 1000 sq. Ft. (About 161 g / m ² ) to about 40 pounds (approximately 18 kg) / 1000 square feet (approximately 195 g / m ² )).

[08] Plate weight is a function of thickness. Since slabs are usually made with varying thicknesses, in the present invention, the density of the slab is used as a measure of the mass of the slab. The benefits of pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention can be appreciated by considering the different densities of the boards, for example about 40 lb / cc. ft (about 641 kg / m ³ ) or less, for example, from about 20 lb / cub. ft (about 320 kg / m ³ ) to about 40 lb / cub. ft (approximately 641 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 37 lb / cub. ft (approximately 593 kg / m ³ ), etc. However, preferred embodiments of the present invention have particular benefit at lower densities when the increased strength provided by the pre-gelatinized partially hydrolyzed starch obtained according to the embodiments of the present invention preferably allows the use of a slab with a lower weight and with good strength and lower water consumption than the case of a plate made from other starches obtained according to another method.

[09] For example, according to some embodiments of the invention, the density of the slab may be from about 20 lb / cc. ft (about 320 kg / m ³ ) to about 35 lb / cub. ft (about 561 kg / m ³ ), for example, from about 20 lb / cub. ft (about 320 kg / m ³ ) to about 34 lb / cub. ft (approximately 545 kg / m ³ ), from approximately 20 lb / cub. ft (about 320 kg / m ³ ) to about 33 lb / cub. ft (approximately 529 kg / m ³ ), from approximately 20 lb / cub. ft (about 320 kg / m ³ ) to about 32 lb / cub. ft (approximately 513 kg / m ³ ), from approximately 20 lb / cub. ft (about 320 kg / m ³ ) to about 31 lb / cub. ft (approximately 497 kg / m ³ ), from approximately 20 lb / cub. ft (about 320 kg / m ³ ) to about 30 lb / cub. ft (approximately 481 kg / m ³ ), from approximately 20 lb / cub. ft (about 320 kg / m ³ ) to about 29 lb / cub. ft (approximately 465 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 35 lb / cub. ft (approximately 561 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 34 lb / cub. ft (approximately 545 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 33 lb / cub. ft (approximately 529 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 32 lb / cub. ft (approximately 513 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 31 lb / cub. ft (approximately 497 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 30 lb / cub. ft (approximately 481 kg / m ³ ), from approximately 21 lb / cub. ft (approximately 336 kg / m ³ ) to approximately 29 lb / cub. ft (approximately 465 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 35 lb / cub. ft (approximately 561 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 34 lb / cub. ft (approximately 545 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 33 lb / cub. ft (approximately 529 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 32 lb / cub. ft (approximately 513 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 31 lb / cub. ft (approximately 497 kg / m ³ ), from approximately 24 lb / cub. ft (about 384 kg / m ³ ) to about 30 lb / cub. ft (about 481 kg / m ³ ) or from about 24 lb / cub. ft (about 384 kg / m ³ ) to about 29 lb / cub. ft (approximately 465 kg / m ³ ).

[010] The pre-gelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention can be added to the suspension to provide an increase in the strength of the product according to the invention, which can be especially useful at lower weight / density. For example, in some embodiments, a slab made in accordance with embodiments of the present invention has a compressive strength of at least about 400 psi (about 2750 kPa) at a density of 29 psi. ft (about 465 kg / m ³ ), as determined according to the method described in example 4. It is preferred that, according to various embodiments of the invention, for different plate densities described herein, it is possible to obtain a plate made according to the method of the invention, strength for compression which is at least about 400 psi (about 2760 kPa), for example at least about 450 psi (about 3100 kPa), at least about 500 psi (about 3450 kPa), at least about 550 psi (about 3800 kPa), according at least about 600 psi (about 4100 kPa), at least about 650 psi (about 4500 kPa), at least about 700 psi (about 4800 kPa), at least about 750 psi (about 5200 kPa), at least about 800 psi (about 5500 kPa), at least about 850 psi (about 5850 kPa), at least about 900 psi (about 6200 kPa), at least about 950 psi (6550 kPa), or at least about 1000 psi (approximately 6900 kPa). In addition, according to some embodiments of the invention, the compressive strength may be limited by any two of the above values. For example, the compressive strength can be from about 450 psi (about 3100 kPa) to about 1000 psi (for example, from about 500 psi (about 3450 kPa) to about 900 psi (about 6200 kPa), from about 600 psi (about 4100 kPa ) to about 800 psi (about 5500 kPa), etc.).

[011] In some embodiments, a board manufactured according to the invention complies with the test protocols set forth in ASTM C473-10. For example, according to some embodiments of the invention, when casting a slab with a thickness of ½ inch (1.27 cm), the pulling resistance of the nails of said slab is at least about 65 pounds (about 30 kg), as determined according to ASTM C473-10, for example, at least about 68 pounds (about 30 kg), at least about 70 pounds (about 32 kg), at least about 72 pounds (about 33 kg), at least about 75 pounds (about 34 kg), at least about 77 pounds (about 35 kg) and the like. According to various embodiments of the invention, the pulling resistance of the nails can be from about 68 pounds (about 30 kg) to about 100 pounds (about 45 kg), for example, from about 68 pounds (about 30 kg) to about 95 pounds (about 43 kg), from about 68 pounds (about 30 kg) to about 90 pounds (about 41 kg), from about 68 pounds (about 30 kg) to about 85 pounds (about 39 kg), from about 68 pounds (about 30 kg) to about 80 pounds (about 36 kg), from about 68 pounds (about 30 kg) to about 77 pounds (about 35 kg ), from about 68 pounds (about 30 kg) to 75 pounds (about 34 kg), from about 68 pounds (about 30 kg) to about 72 pounds (about 33 kg), from about 68 pounds (about 30 kg) to about 70 pounds (about 32 kg), from about 70 pounds (about 32 kg) to about 100 pounds (about 45 kg), from about 70 pounds (about 32 kg) to about 95 pounds (about 43 kg), from about 70 pounds (about 32 kg) to about 90 pounds (about 41 kg), from about 70 pounds (about 32 kg) to about 85 pounds (about 39 kg), from about 70 pounds (about 32 kg) to about 80 pounds tov (about 36 kg), from about 70 pounds (about 32 kg) to about 77 pounds (about 35 kg), from about 70 pounds (about 32 kg) to 75 pounds (about 34 kg), from about 70 pounds (about 32 kg) to about 72 pounds (about 33 kg), from about 72 pounds (about 33 kg) to about 100 pounds (about 45 kg), from about 72 pounds (about 33 kg) to about 95 pounds (about 43 kg) from about 72 pounds (about 33 kg) to about 90 pounds (about 41 kg), from about 72 pounds (about 33 kg) to about 85 pounds (about 39 kg), from about 72 pounds (about 33 kg) up to about 80 pounds (about 36 kg), from about 72 pounds (about 33 kg) to about 77 pounds (about 35 kg), from about 72 pounds (about 33 kg) to 75 pounds (about 34 kg), from 75 pounds (about 34 kg) to about 100 pounds (about 45 kg), from 75 pounds (about 34 kg) to about 95 pounds (about 43 kg), from 75 pounds (about 34 kg) to about 90 pounds (about 41 kg) , from 75 pounds (about 34 kg) to about 85 pounds (about 39 kg), from 75 pounds (about 34 kg) to about 80 pounds (about 36 kg), from 75 pounds (about 34 kg) to about 77 pounds ( approximately 35 kg), about about 77 pounds (about 35 kg) to about 100 pounds (about 45 kg), from about 77 pounds (about 35 kg) to about 95 pounds (about 43 kg), from about 77 pounds (about 35 kg) to about 90 pounds (about 41 kg), from about 77 pounds (about 35 kg) to about 85 pounds (about 39 kg), or from about 77 pounds (about 35 kg) to about 80 pounds (about 36 kg).

[012] Regarding the bending strength, according to some embodiments of the invention, when casting a ½ inch (1.27 cm) thick plate, the bending strength of said plate leaves at least about 36 pounds (about 16 kg) in the processing direction (for example at least about 38 pounds (about 17 kg), at least about 40 pounds (about 18 kg), etc.) and / or at least about 107 pounds (about 49 kg) (for example, at least about 110 pounds (about 50 kg), at least about 112 pounds (about 51 kg) and .d.) in the transverse direction, as determined according to ASTM C473 standard. According to various embodiments of the invention, the plate may have a flexural strength in the processing direction from about 36 pounds (about 16 kg) to about 60 pounds (about 27 kg), for example, from about 36 pounds (about 16 kg) to about 55 pounds ( about 25 kg), from about 36 pounds (about 16 kg) to about 50 pounds (about 23 kg), from about 36 pounds (about 16 kg) to about 45 pounds (about 20 kg), from about 36 pounds (about 16 kg) to about 40 pounds (about 18 kg), from about 36 pounds (about 16 kg) to about 38 pounds (about 17 kg), from about 38 pounds (about 17 kg) to about 60 pounds (about 27 kg), from about 38 pounds (about 17 kg) to about 55 pounds (about 25 kg), from about 38 pounds (about 17 kg) to about 50 pounds (about 23 kg), from about 38 pounds (about 17 kg) to about 45 pounds (about 20 kg), from about 38 pounds (about 17 kg) to about 40 pounds (about 18 kg) from about 40 pounds (about 18 kg) to about 60 pounds (about 27 kg), from about 40 pounds (about 18 kg) to about 55 pounds (about 25 kg), from about 40 pounds (approx. 18 kg) to about 50 pounds (about 23 kg) or about 40 pounds (about 18 kg) to about 45 pounds (about 20 kg). According to various embodiments of the invention, the transverse bending strength of the plate may be from about 107 pounds (about 49 kg) to about 130 pounds (about 59 kg), for example, from about 107 pounds (about 49 kg) to about 125 pounds ( about 57 kg), from about 107 pounds (about 49 kg) to about 120 pounds (about 54 kg), from about 107 pounds (about 49 kg) to about 115 pounds (about 52 kg), from about 107 pounds (about 49 kg) to about 112 pounds (about 51 kg), from about 107 pounds (about 49 kg) to approx 110 pounds (about 50 kg), from about 110 pounds (about 50 kg) to about 130 pounds (about 59 kg), from about 110 pounds (about 50 kg) to about 125 pounds (about 57 kg), from about 110 pounds (about 50 kg) to about 120 pounds (about 54 kg), from about 110 pounds (about 50 kg) to about 115 pounds (about 52 kg), from about 110 pounds (about 50 kg) to about 112 pounds (about 51 kg), from about 112 pounds (about 51 kg) to about 130 pounds (about 59 kg), from about 112 pounds (about 51 kg) to about 125 pounds (about 57 kg), but 112 pounds (about 51 kg) to about 120 pounds (about 54 kg), or from about 112 pounds (about 51 kg) to about 115 pounds (about 52 kg).

[013] Furthermore, according to some embodiments of the invention, the average hardness of the core of the board may be at least about 11 pounds (about 5 kg), for example at least about 12 pounds (about 5.4 kg), at least about 13 pounds (about 5.9 kg), at least about 14 pounds (about 6.4 kg), at least about 15 pounds (about 6.8 kg), at least about 16 pounds (about 7.3 kg) at least about 17 pounds (about 7.7 kg), at least about 18 pounds (about 8.2 kg), at least p approximately 19 pounds (about 8.6 kg), at least about 20 pounds (about 9.1 kg), at least about 21 pounds (about 9.5 kg), or at least about 22 pounds (about 10.0 kg) as determined according to ASTM C473-10. According to some embodiments of the invention, the hardness of the core of the board can be from about 11 pounds (about 5 kg) to about 25 pounds (about 11.3 kg), for example, from about 11 pounds (about 5 kg) to about 22 pounds (about 10, 0 kg), from about 11 pounds (about 5 kg) to about 21 pounds (about 9.5 kg), from about 11 pounds (about 5 kg) to about 20 pounds (about 9.1 kg), from about 11 pounds (about 5 kg) to about 19 pounds (about 8.6 kg), from about 11 pounds (about 5 kg) to about 18 pounds (about 8.2 kg), from approx about 11 pounds (about 5 kg) to about 17 pounds (about 7.7 kg), from about 11 pounds (about 5 kg) to about 16 pounds (about 7.3 kg), from about 11 pounds (about 5 kg) up to about 15 pounds (about 6.8 kg), from about 11 pounds (about 5 kg) to about 14 pounds (about 6.4 kg), from about 11 pounds (about 5 kg) to about 13 pounds (about 5, 9 kg), from about 11 pounds (about 5 kg) to about 12 pounds (about 5.4 kg), from about 12 pounds (about 5.4 kg) to about 25 pounds (about 11.3 kg), from about 12 lbs. (Approximately 5.4 kg) to approximately 22 lbs. nt (about 10.0 kg), from about 12 pounds (about 5.4 kg) to about 21 pounds (about 9.5 kg), from about 12 pounds (about 5.4 kg) to about 20 pounds (about 9 1 kg), from about 12 pounds (about 5.4 kg) to about 19 pounds (about 8.6 kg), from about 12 pounds (about 5.4 kg) to about 18 pounds (about 8.2 kg) from about 12 pounds (about 5.4 kg) to about 17 pounds (about 7.7 kg), from about 12 pounds (about 5.4 kg) to about 16 pounds (about 7.3 kg), from about 12 pounds (about 5.4 kg) to about 15 pounds (about 6.8 kg), from about 12 pounds tov (about 5.4 kg) to about 14 pounds (about 6.4 kg), from about 12 pounds (about 5.4 kg) to about 13 pounds (about 5.9 kg), from about 13 pounds (about 5 9 kg) to about 25 pounds (about 11.3 kg), from about 13 pounds (about 5.9 kg) to about 22 pounds (about 10.0 kg), from about 13 pounds (about 5.9 kg) up to about 21 pounds (about 9.5 kg), from about 13 pounds (about 5.9 kg) to about 20 pounds (about 9.1 kg), from about 13 pounds (about 5.9 kg) to about 19 pounds (about 8.6 kg), from about 13 pounds (about 5.9 kg) to about 18 pounds in (about 8.2 kg), from about 13 pounds (about 5.9 kg) to about 17 pounds (about 7.7 kg), from about 13 pounds (about 5.9 kg) to about 16 pounds (about 7 3 kg), from about 13 pounds (about 5.9 kg) to about 15 pounds (about 6.8 kg), from about 13 pounds (about 5.9 kg) to about 14 pounds (about 6.4 kg) from about 14 pounds (about 6.4 kg) to about 25 pounds (about 11.3 kg), from about 14 pounds (about 6.4 kg) to about 22 pounds (about 10.0 kg), from about 14 pounds (about 6.4 kg) to about 21 pounds (about 9.5 kg), from about 14 pounds (about 6.4 kg) to about 20 pounds (about 9.1 kg), from about 14 pounds (about 6.4 kg) to about 19 pounds (about 8.6 kg), from about 14 pounds (about 6, 4 kg) to about 18 pounds (about 8.2 kg), from about 14 pounds (about 6.4 kg) to about 17 pounds (about 7.7 kg), from about 14 pounds (about 6.4 kg) to about 16 pounds (about 7.3 kg), from about 14 pounds (about 6.4 kg) to about 15 pounds (about 6.8 kg), from about 15 pounds (about 6.8 kg) to about 25 pounds ( about 11.3 kg), from about 15 pounds (about 6.8 kg) to about 22 pounds (about 10.0 kg), from about 15 pounds (about 6.8 kg) to about 21 pounds (about 9.5 kg), from about 15 pounds (about 6.8 kg) to about 20 pounds (about 9, 1 kg), from about 15 pounds (about 6.8 kg) to about 19 pounds (about 8.6 kg), from about 15 pounds (about 6.8 kg) to about 18 pounds (about 8.2 kg), from about 15 pounds (about 6.8 kg) to about 17 pounds (about 7.7 kg), from about 15 pounds (about 6.8 kg) to about 16 pounds (about 7.3 kg), from about 16 pounds (about 7.3 kg) to about 25 pounds (about 11.3 kg), from about 16 pounds ( approximately 7.3 kg) to about 22 pounds (about 10.0 kg), from about 16 pounds (about 7.3 kg) to about 21 pounds (about 9.5 kg), from about 16 pounds (about 7.3 kg) to about 20 pounds (about 9.1 kg), from about 16 pounds (about 7.3 kg) to about 19 pounds (about 8.6 kg), from about 16 pounds (about 7.3 kg) to about 18 pounds (about 8.2 kg), from about 16 pounds (about 7.3 kg) to about 17 pounds (about 7.7 kg), from about 17 pounds (about 7.7 kg) to about 25 pounds (about 11.3 kg), from about 17 pounds (about 7.7 kg) to about 22 pounds (ex approximately 10.0 kg), from about 17 pounds (about 7.7 kg) to about 21 pounds (about 9.5 kg), from about 17 pounds (about 7.7 kg) to about 20 pounds (about 9.1 kg), from about 17 pounds (about 7.7 kg) to about 19 pounds (about 8.6 kg), from about 17 pounds (about 7.7 kg) to about 18 pounds (about 8.2 kg), about 18 pounds (about 8.2 kg) to about 25 pounds (about 11.3 kg), from about 18 pounds (about 8.2 kg) to about 22 pounds (about 10.0 kg), from about 18 pounds ( about 8.2 kg) to about 21 pounds (about 9.5 kg), from about 18 pounds (at 8.2 kg) to about 20 pounds (about 9.1 kg), from about 18 pounds (about 8.2 kg) to about 19 pounds (about 8.6 kg), from about 19 pounds (about 8.6 kg) to about 25 pounds (about 11.3 kg), from about 19 pounds (about 8.6 kg) to about 22 pounds (about 10.0 kg), from about 19 pounds (about 8.6 kg) to about 21 pounds (about 9.5 kg), from about 19 pounds (about 8.6 kg) to about 20 pounds (about 9.1 kg), from about 21 pounds (about 9.5 kg) to about 25 pounds (about 11.3 kg), from about 21 pounds (about 9.5 kg) to about 22 pounds (example about 10.0 kg), or from about 22 pounds (about 10.0 kg) to about 25 pounds (about 11.3 kg).

[014] Due to the at least partially viscous characteristic in the mid-range, which allows some embodiments of the present invention to be provided, these standards (for example, nail pull-out resistance, flexural strength and core hardness) can be met even with an ultra small plate density (for example, about 31 lb / cubic foot (about 497 kg / m ³ ) or less), as described herein.

[015] The inventors have also found that pregelatinized partially hydrolyzed starches obtained according to embodiments of the present invention exhibit hydration rates at a predetermined temperature increase (TRS) comparable or superior to hydration rates of conventional pregelatinized starches obtained according to another method. The required setting time may depend on the composition, while the required setting time can be determined by a person of ordinary skill in the art, depending on the production conditions and the raw materials available.

[016] A product according to embodiments of the present invention can be obtained from conventional production lines. For example, plate manufacturing techniques are described, for example, in US Pat. No. 7,364,676 and in the publication of US Patent Application 2010/0247937. In short, in the case of gypsum board, the method used typically involves unloading the sheathing sheet onto a moving conveyor. Since gypsum board is usually produced “face down”, the specified sheathing sheet is a “front” sheathing sheet according to such embodiments of the invention.

[017] The dry and / or wet components of the gypsum slurry are loaded into a mixer (eg, a finger mixer), where they are mixed to form a gypsum slurry. The mixer comprises a main unit and a discharge pipe (for example, an inlet channel-container-funnel device known in the art or a device described in US Pat. Nos. 6,494,609 and 6,874,930). In some embodiments, the injection conduit may include a slurry spreader, either with one feed inlet or with multiple feed openings, such as dispensers described in US Patent Application Publication 2012/0168527 A1 (Application No. 13/341016) and in the publication of the application US patent 2012/0170403 A1 (application No. 13/341209), for example. In these embodiments, when using a multi-feed slurry dispenser, the discharge pipe may include a suitable flow separator, such as those described in US Patent Application Publication 2012/0170403 A1. If necessary, a foaming agent can be added to the mixer discharge pipe (for example, to the inlet, as described, for example, in US Pat. Nos. 5,683,635 and 6,494,609). The suspension discharged from the discharge line after adding all the ingredients, including the foaming agent, is the primary gypsum suspension that will form the core of the slab. Such a suspension for forming the core of the plate is discharged onto a moving front cladding sheet.

[018] The front skin sheet may have a thin overlay layer in the form of a relatively dense suspension layer. In addition, hard edges, as is known in the art, can be formed, for example, from the same slurry stream from which the face covering layer is obtained. According to embodiments of the invention, when foam is introduced into the injection conduit, the secondary gypsum slurry stream can be removed from the mixer unit to obtain a dense suspension to form a topcoat, which can then be used to produce a front topcoat and hard edges, as is known in the art. In use, the front cover layer and hard edges are usually placed on the moving front cover sheet before applying the slurry to form the core, typically in front of the mixer. After unloading from the injection pipeline, the core-forming slurry is distributed, if necessary, over the front cladding sheet (optionally having a topcoat) and coated with a second cladding sheet (usually the “back” cladding sheet) to obtain a wet prefabricated structure in the form of a layered structure, which is plate preparation for the final product. The second cladding sheet may optionally have a second coating layer, which can be formed from the same or different secondary (dense) gypsum slurry, as in the case of the facial covering layer, if present. Sheathing sheets can be made of paper, fiber mat or other type of material (e.g., foil, plastic, glass mat, non-woven material, such as a mixture of cellulosic and inorganic filler, etc.).

[019] The wet assembly thus obtained is transferred to a forming section where the product is brought to the desired thickness (for example, using a molding plate) and to one or more knife sections where it is cut to the required length. The wet prefabricated structure is allowed to solidify to form an interwoven crystalline matrix of the captured gypsum, and excess water is removed through a drying process (for example, by moving the prefabricated structure through a kiln). Surprisingly and unexpectedly, it was found that a plate obtained according to the invention using pre-gelatinized partially hydrolyzed starch obtained according to embodiments of the present invention requires significantly less time during the drying process due to the low water consumption of starch. This is an advantage because it allows to reduce energy costs.

[020] Furthermore, in the manufacture of gypsum board, vibration is often used to remove large pores or air pockets from the precipitated slurry. All of the steps described above are known in the art, as well as processes and equipment for carrying out the steps.

[021] The pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention can be used in the manufacture of various products, such as, for example, gypsum wallboard, acoustic (eg, ceiling) tile, joint sealant, gypsum and cellulose fiber products, such like a wall plate made of gypsum and wood fiber, etc. According to some embodiments of the invention, said product may be made from a suspension according to embodiments of the present invention.

[022] Essentially, pregelatinized partially hydrolyzed starch obtained in an extruder according to embodiments of the present invention can have a beneficial effect, as described herein, in a product other than paper pasted gypsum board according to embodiments of the present invention. For example, pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention can be used in upholstered products (e.g., fabric) in which the casing sheets are in the form of fibrous mats. Such mats may optionally have a topcoat to reduce water permeability. Other ingredients that can be used to produce such a mat-covered product, as well as materials for making fibrous mats and manufacturing methods, are discussed, for example, in US Pat. No. 8,070,895, as well as in the publication of US Patent Application 2009/0247937.

[023] In addition, the product made of gypsum and cellulose may be in the form of cellulose particles (eg, wood fibers), gypsum, pregelatinized partially hydrolyzed starch obtained according to embodiments of the present invention, and other ingredients (eg, water-resistant additives, such as siloxanes), if necessary. Other ingredients and manufacturing methods are discussed, for example, in US Pat. Nos. 4,328,178; 4,239,716; 4,392,896; 4,645,548; 5,320,677; 5,817,262; and 7413603.

Illustrative Examples of Embodiments

[024] According to one embodiment of the invention, a method for producing pregelatinized partially hydrolyzed starch comprises: (a) mixing at least water, non-pregelatinized starch and a weak acid that substantially does not form chelates with calcium ions to produce a wet starch-containing substance precursor with a moisture content of from about 8% of the mass. up to about 25% of the mass .; (b) feeding said wet starch precursor to the extruder; and (c) pre-gelatinization and acid modification of the wet starch-containing precursor substance in the extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF).

[025] According to another embodiment of the invention, the pressure inside the extruder is at least about 2000 psi (about 13800 kPa).

[026] According to another embodiment of the invention, the cold solubility of the pregelatinized partially hydrolyzed starch is greater than about 50%.

[027] According to another embodiment of the invention, the viscosity in cold water (10% solids, 25 ºC) of pregelatinized partially hydrolyzed starch is from about 10 Brabender units (BU) to about 120 BU.

[028] According to another embodiment of the invention, the viscosity characteristic of the pregelatinized partially hydrolyzed starch is from about 20 centipoise to about 700 centipoise when measuring viscosity when exposed to starch conditions according to the VMA method.

[029] According to another embodiment of the invention, the viscosity (10% solids, 93 ° C) of the pre-gelatinized partially hydrolyzed starch is from about 5 BU to about 33 BU.

[030] According to another embodiment of the invention, the weak acid, which essentially does not form chelates with calcium ions, contains alum.

[031] According to another embodiment of the invention, tartaric acid is added to the mixture to produce wet starch-containing precursor.

[032] According to other variants of the invention, the amount of weak acid, which essentially does not form chelates with calcium ions, is from about 0.5% of the mass. up to about 5% of the mass. by weight relative to the mass of starch.

[033] According to another variant implementation of the invention, the moisture content of wet starch is from about 10% of the mass. up to about 20% of the mass. by weight relative to the weight of the starch-containing precursor substance.

[034] In another embodiment, pregelatinization and acid modification occurs in an extruder at a head temperature of at least about 175 ºC (about 350 ºF) to about 205 ºC (about 400 ºF).

[035] According to another embodiment of the invention, the yield of pregelatinized partially hydrolyzed starch is at least about 100 kg / h in an extruder.

[036] According to another embodiment of the invention, pregelatinization and acid modification occurs within less than about 5 minutes.

[037] According to another embodiment of the invention, pregelatinization and acid modification occurs within less than about 1 minute.

[038] According to another embodiment of the invention, the proposed method does not include the stage of purification pregelatinized partially hydrolyzed starch.

[039] According to another embodiment of the invention, the proposed method does not include the step of neutralizing pre-gelatinized partially hydrolyzed starch.

[040] According to another embodiment of the invention, the degree of gelatinization of the pregelatinized partially hydrolyzed starch is at least about 70%.

[041] According to another embodiment of the invention, pregelatinized partially hydrolyzed starch is prepared according to embodiments of the present invention.

[042] According to another embodiment of the invention, the proposed method for the preparation of pregelatinized partially hydrolyzed starch comprises: (a) mixing at least water, non-pregelatinized starch and a strong acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% of the mass., while a strong acid is present in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch; (b) feeding said wet starch precursor to the extruder; and (c) pregelatinization and acid modification of wet starch in an extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF).

[043] According to another embodiment of the invention, the proposed method for the preparation of pregelatinized partially hydrolyzed starch comprises: (a) mixing at least water, non-pregelatinized starch and a strong acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% of the mass., while the strong acid is present in an amount of about 0.01% of the mass. or less by weight relative to the mass of starch; (b) feeding said wet starch precursor to the extruder; and (c) pregelatinization and acid modification of wet starch in an extruder at a head temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF).

[044] According to another embodiment of the invention, the pKa of the strong acid is about -1.7 or less.

[045] According to another embodiment of the invention, the strong acid is sulfuric acid, nitric acid, hydrochloric acid, or any combination thereof.

[046] According to another embodiment of the invention, the proposed method of manufacturing a stove includes: (a) obtaining pre-gelatinized partially hydrolyzed starch by (i) mixing at least water, non-pregelatinized starch and acid to produce a wet starch-containing precursor substance with a moisture content of from about 8% by weight . up to about 25% wt., while the acid is selected from the group consisting of: (1) a weak acid, which essentially does not form chelates with calcium ions, (2) a strong acid in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch or (3) any combination thereof; (ii) feeding the wet starch-containing precursor to the extruder; and (iii) pregelatinization and acid modification of wet starch in a die-type extruder at a temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF); (b) mixing the gelled and partially hydrolyzed starch with at least water and gypsum to form a slurry; (c) placing the suspension between the first cladding sheet and the second cladding sheet to obtain a wet precast structure; (d) cutting a wet prefabricated structure to form a slab; and (e) drying the stove.

[047] According to another embodiment of the invention, the strong acid is present in an amount of about 0.01% by weight. or less by weight relative to the mass of starch.

[048] According to another embodiment of the invention, the inventive method for making a slab includes (a) preparing pregelatinized partially hydrolyzed starch by (i) mixing at least water, non-pregelatinized starch and a weak acid that does not substantially form chelates with calcium ions to produce wet starch-containing precursor with a moisture content of from about 8% of the mass. up to about 25% of the mass .; (ii) feeding the wet starch to the extruder; and (iii) pregelatinization and acid modification of wet starch in a die-type extruder at a temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF); (b) mixing pregelatinized and partially hydrolyzed starch with at least water and gypsum to form a slurry; (c) placing the suspension between the first cladding sheet and the second cladding sheet to obtain a wet precast structure; (d) cutting a wet prefabricated structure to form a slab; and (e) drying the stove.

[049] According to another embodiment of the invention, the inventive method for manufacturing a slab comprises: (a) mixing at least water, non-gelatinized starch and a strong acid to produce a wet starch-containing precursor substance with a moisture content of about 8% by weight. up to about 25% of the mass., while a strong acid is present in an amount of about 0.05% of the mass. or less by weight relative to the mass of starch; (ii) feeding said wet starch-containing precursor to an extruder; and (iii) pregelatinization and acid modification of wet starch in a head extruder at a temperature of from about 150 ºC (about 300 ºF) to about 210 ºC (about 410 ºF); (b) mixing pregelatinized and partially hydrolyzed starch with at least water and gypsum to form a slurry; (c) placing the suspension between the first cladding sheet and the second cladding sheet to obtain a wet precast structure; (d) cutting a wet prefabricated structure to form a slab; and (e) drying the stove.

[050] According to another embodiment of the invention, the strong acid is present in an amount of about 0.01% by weight. or less by weight relative to the mass of starch.

[051] According to another embodiment of the invention, the captured gypsum core has a compressive strength greater than the captured gypsum core made using starch obtained according to another method.

[052] According to another embodiment of the invention, when the gelatinization of the pre-gelatinized partially hydrolyzed starch is added to the suspension, the degree of gelation is at least about 70%, with additional gelation occurring in the drying step.

[053] According to another embodiment of the invention, the pregelatinized partially hydrolyzed starch is fully gelled when added to the suspension.

[054] According to another embodiment of the invention, the compressive strength of the slab is at least about 400 psi (about 2760 kPa) (2800 kPa) at a density of 29 lb / cc. ft (approximately 465 kg / m ³ ).

[055] According to another embodiment of the invention, the hardness of the core of the board is at least about 11, as determined according to ASTM C473-10.

[056] According to another embodiment of the invention, the density of the slab is from about 21 lb / cc. ft (approximately 336 kg / m ³ ) to approximately 35 lb / cub. ft (approximately 561 kg / m ³ ).

[057] According to another embodiment of the invention, the suspension further comprises sodium trimetaphosphate.

[058] According to another embodiment of the invention, the amount of water that must be added to maintain the fluidity of the suspension at the same level that would be without the use of pregelatinized partially hydrolyzed starch is less than the increase in the amount of water required when using pregelatinized partially hydrolyzed starch obtained according to another way.

[059] According to another embodiment of the invention, the amount of starch is from about 0.5% to about 10% by weight based on the weight of the plaster.

[060] According to another embodiment of the invention, a wall plate is prepared according to embodiments of the present invention.

[061] It should be noted that the preceding description is merely examples of embodiments of the invention. Due to the completeness of the description provided herein, other typical embodiments of the invention are apparent. A person of ordinary skill in the art will also appreciate that each of these embodiments of the invention can be used in various combinations with the other embodiments presented herein.

[062] The following examples further illustrate the invention, but, of course, should not be construed as limiting its scope in any way.

EXAMPLE 1

[063] The present example illustrates the preparation of pregelatinized partially hydrolyzed starches according to embodiments of the present invention.

[064] To conduct various tests for specific properties (eg, viscosity, fluidity, strength), nine pregelatinized partially hydrolyzed starches obtained according to embodiments of the present invention were obtained. Said nine starches according to the invention were investigated together with three commercially available starches.

[065] According to the method of the invention, for preparing pregelatinized partially hydrolyzed starch, wet starch precursors were obtained by mixing corn without germ, which can be purchased in the form of yellow corn flour CCM 260 from Bunge North America, St. Louis, Missouri, in an amount of 100 kg, varying amounts of aluminum sulfate (alum), a weak acid that essentially does not form chelates with calcium ions, and / or tartaric acid (less than 20% by weight of the total amount of weak acids from) and varying amounts of water. Wet starch-containing precursors were loaded into a single screw extruder, which can be purchased as Advantage 50 from American International (South Beloit, Illinois). In the extruder, wet starch-containing precursor substances were subjected to pregelatinization and acid modification in one step, so that these processes occurred simultaneously.

[066] the following table 4 shows the extrusion of corn flour in the presence of acid. The extrusion time (i.e. pre gelatinization and acid modification time) was less than 30 seconds. All percentages are calculated on the basis of the total mass of starch, with the exception of moisture, the amount of which was calculated on the basis of the total mass in the wet state, expressed as the sum of the mass of water, starch and other additives.

[067] The resulting pregelatinized partially hydrolyzed starches were evaluated compared to conventional pregelatinized corn starch with a viscosity of 773 centipoise, designated as composition 1A (comparative), as well as two low water starches obtained by extrusion of acid-modified corn starches, which purchased as Clinton 277 (ADM, Chicago, Illinois) and Caliber 159 (Cargill, Wiset, Minnesota), designated as composition 1B (comparative) and composition 1C (comparative), co respectively.

Table 4

Substance Corn flour Canola oil 0.25% of the mass. Liquid alum 1% of the mass. - 4% of the mass. Wine acid 0% of the mass. - 0.3% of the mass. Moisture in starch during extrusion 10% of the mass. - 20% of the mass. Main auger (rpm) 350 Loading Auger Speed (r / min) fourteen Head Temperature (ºF) 350-370
(about 177-188 ^about C) Knife speed (r / min) 400-1000

[068] During the extrusion process, pre-gelatinized partially hydrolyzed starches, designated as 1D-1L compositions, were prepared.

[069] Table 5 below provides details of the various moisture contents for extrusion and the acid content during extrusion in the case of 1D-1L compositions. Compositions 1D-1H and 1L were obtained at a moisture content of 16% by weight, while compositions 1I-1K were obtained at a moisture content of 13% by mass. Compositions 1D-1G and compositions 1I-1L were obtained using liquid alum in an amount ranging from 1% of the mass. up to 4% wt., while the composition 1H contained liquid alum and tartaric acid. Compositions 1F and 1L were obtained using the same moisture content and the amount of acid, but in Example 3 these compositions contained different amounts of setting retarder.

Table 5

Composition Moisture Acid Composition 1A 16% of the mass. There is no data Composition 1B 19% of the mass. There is no data Composition 1C 19% of the mass. There is no data Composition 1D 16% of the mass. 1% of the mass. alum Composition 1E 16% of the mass. 2% of the mass. alum Composition 1F 16% of the mass. 3% of the mass. alum Composition 1G 16% of the mass. 4% of the mass. alum Composition 1H 16% of the mass. 2% of the mass. alum;
0.3% of the mass. tartaric acid Composition 1I 13% of the mass. 1% of the mass. alum Composition 1J 13% of the mass. 2% of the mass. Composition 1K 13% of the mass. 3% of the mass. alum Composition 1L 16% of the mass. 3% of the mass. alum

[070] In examples 2-4, described below, tested the composition shown in table 5, for various properties. In Example 2, compositions 1B-1L were evaluated for viscosity in amylographic tests. In Example 3, suspensions prepared using one of compositions 1A, 1D-1I, and 1K-1L were examined for fluidity, which was evaluated by a cone draft test. Then, the obtained data was additionally confirmed by measuring the time until reaching 50% hydration of the suspensions. Such measurements showed how long it took to set the suspensions. In Example 4, suspensions prepared using compositions 1A, 1D-1I, and 1K were examined for strength, which was evaluated by the compression test described herein.

EXAMPLE 2

[071] The present example illustrates the viscosity of pregelatinized partially hydrolyzed starches obtained in an extruder according to embodiments of the present invention. Compositions 1D-1K were investigated in comparison with extruded commercially available acid-modified starches (compositions 1B-1C), in particular with respect to changes in viscosity depending on the amount of acid (e.g. alum) and moisture content, determined by the moisture level in wet starch, downloadable through an extruder.

[072] In preparation for the test, the test compositions were mixed with water in a starch suspension so that the starch suspension contained these compositions in an amount of 10% by weight. It should be noted that the term “solution” is used when the starch is completely gelled and completely dissolved, and the term “suspension” is used when the starch is not completely dissolved. Then, each composition was tested for viscosity at different temperatures using the amylographic method described herein. The test results are graphically depicted in FIG. 1 and 2, which are amylograms that allow one to evaluate the viscosity of pregelatinized partially hydrolyzed starches at different temperatures by graphically depicting the dependence of viscosity (left y axis) and temperature (right y axis) on time (x axis). The temperature curve passes over the curve of each sample. The same temperature profile was used for each sample. Other curves show the viscosity of starches.

[073] The initial viscosity at 25 ° C was an indicator of the fluidity of the suspension system containing any of the compositions 1B-1K. 25ºC is the temperature at which starch will be mixed with building gypsum and other ingredients to make the slab. In addition, at this temperature, the viscosity of starch negatively correlates with the fluidity of the stucco suspension.

[074] The minimum viscosity (93ºC) was an indication of the molecular weight of any of the compositions 1B-1K. At a temperature of 93ºC, starch molecules completely dissolve in water. The viscosity of starch solutions at 93 ° C positively correlates with the molecular weight of starch, which is the result of partial hydrolysis.

[075] FIG. 1 is an amylogram obtained by plotting the values of viscosity (left y axis) and temperature (right y axis) with respect to a fifty minute time period (x axis). Comparative compositions 1B and 1C and the compositions 1D-1H according to the invention described herein were mixed in starch solutions in an amount of 10% by weight based on the weight of the solution. To avoid clumping of starch, starch was added to the water in the mixing cup of the Waring mixer while stirring at low speed for 20 seconds. Then, starch solutions were evaluated using a Visograph-E (CW Brabender® (Brabender) Instruments, Inc., South Hackensack, NJ). According to the method of measuring the Brabender viscosity described herein, the viscosity is measured using a CW Brabender, for example, Visograph-E, in which torque is used for dynamic measurements. It should be noted that, as defined herein, Brabender units are measured using a 16 fluid ounce sample cup (approximately 500 cm ³ ) with a 700 cmg cartridge at 75 rpm. One of ordinary skill in the art will also readily understand that Brabender units can be converted to other units of viscosity, such as centipoises (e.g. cn = BU × 2.1 when using a 700 cmg measuring cartridge) or Krebs units as described herein . Bonding profiles of compositions 1D-1H, extruded at 16% of the mass. moisture content are shown in FIG. 1 together with comparative compositions 1B and 1C.

[076] Considering the proposed in the invention composition 1D-1H shows that with an increase in the content of alum from 1% of the mass. up to 4% of the mass. the initial viscosity decreased from 70 Brabender units (BU) to 10 BU, while the molecular weight also decreased. The initial viscosities and viscosities at 93ºC of compositions 1D-1H were reduced to the viscosities of compositions 1B and 1C. Compositions 1B and 1C showed the usual ultimate viscosity of starches with low water consumption.

[077] The results of a study of the 1D-1H compositions shown in FIG. 1 demonstrate that an optimum acid modification can be achieved during the extrusion process. The results also show that the inventive method for producing pregelatinized partially hydrolyzed starch has successfully reduced the viscosity (molecular weight) of starch. No maximum viscosity was observed in the range of 70ºC to 90ºC, which indicates that the 1D-1H compositions were completely gelled. If the 1D-1H compositions were not completely gelled, an increase in viscosity would occur. Complete gelatinization of starch compositions was confirmed by differential scanning calorimetry (DSC).

[078] FIG. 2 is a second amylogram obtained by plotting the values of viscosity (left y axis) and temperature (right y axis) over a fifty minute time period (x axis). All comparative compositions 1B and 1C and the compositions 1I-1K proposed in the invention described herein were mixed in starch solutions in an amount of 10% by weight based on the weight of the solution. To avoid clumping of starch, starch was added to the water in the mixing cup of the Waring mixer while stirring at low speed for 20 seconds. Then, starch solutions were evaluated using a visograph E. The bonding profiles of compositions 1I-1K extruded at 13% by weight. moisture content shown in FIG. 2 together with comparative compositions 1B and 1C.

[079] Similar trends observed with 1D-1H compositions were observed with 1I-1K compositions. In particular, the method for producing pregelatinized partially hydrolyzed starch in an extruder described herein has successfully reduced the viscosity of compositions 1I-1K.

[080] With an increase in the content of alum from 1% of the mass. up to 3% of the mass. the initial viscosity decreased from 75 BU to 14 BU, while the molecular weight also decreased. The initial viscosities and viscosities at 93 ° C of compositions 1I - 1K were reduced to the viscosities of compositions 1B and 1C.

[081] In addition, the results of the study of compositions 1I-1K shown in FIG. 2 demonstrate that an optimum acid modification can be achieved during the extrusion process. No viscosity maximum was observed in the range of 70ºC to 90ºC, which indicates that the 1I-1K compositions were completely gelled.

[082] In addition, the results showed that with a lower moisture content, it is possible to hydrolyze a larger amount of starch at a given acid level than with a higher moisture content, since at a lower moisture content there is more mechanical energy and, therefore, more starch decomposes, so that starch becomes less when you apply the same level of acid.

EXAMPLE 3

[083] The present example illustrates the fluidity of gypsum suspensions containing compositions 1A (comparative), 1D-1I and 1K-1L. Compositions were evaluated for yield using a cone draft test, as will be understood by a person of ordinary skill in the art.

[084] In preparation for the test, suspensions were prepared with each of compositions 1A (comparative), 1D-1I, and 1K-1L in an amount of 2 wt%, the parameters are shown in Table 6 below, the applied ratio of water to plaster (WSR) was 100 .

Table 6

Ingredient Mass (g) Plaster 400 Heat-resistant setting accelerator four Starch 8 10% sodium trimetaphosphate solution 8 Dispersant 2 1% retarder solution twenty Mixing water 357 Foam PFM-33 (0.5% solution) 25

[085] The starch was weighed and added to a dry mix containing plaster with a purity higher than 95% and a heat-resistant setting accelerator. Water, sodium trimetaphosphate (10 wt.% Solution), dispersant and retarder were weighed in the mixing bowl of a Hobart mixer. The dry mixture was poured into the mixing bowl of the mixer, which can be purchased as an N50 5-Quart mixer at Hobart (Troy, Ohio), soaked for 10 seconds and mixed at a speed of II for 30 seconds. To obtain the foam, a 0.5% Hyonic® PFM-33 Soap Solution (HUIC) (prepared by GEO® Specialty Chemicals, Ambler, PA) was prepared and then mixed with air to give air foam. The specified air foam was added to the suspension using a foam generator.

[086] Then, each suspension was placed in a cylinder with a diameter of 4.92 cm (1.95 inches) and a height of 10 cm (3.94 inches). Next, the cylinder was raised, allowing the suspension to flow freely. Then, to demonstrate the fluidity of the suspensions, the diameters of the formed cone sediments were measured and the obtained values were recorded below in Table 7. Table 8 also shows the results of determining the time during the test to achieve 50% hydration, which is described in more detail below.

Table 7

Composition Retarder Cone draft (cm) Time to 50% hydration (minutes) Composition 1A 0.05% of the mass. 13.7 cm (5 3/8 in.) four Composition 1D 0.05% of the mass. 16.5 cm (6 1/2 inches) 3.8 Composition 1E 0.05% of the mass. 15.2 cm (6 inches) 3.6 Composition 1F 0.05% of the mass. 16.2 cm (6 3/8 in.) 3,7 Composition 1G 0.05% of the mass. 16.2 cm (6 3/8 in.) 3.3 Composition 1H 0.05% of the mass. 17.8 cm (7 inches) 3,7 Composition 1I 0.05% of the mass. 15.9 cm (6 1/4 in.) 3.6 Composition 1K 0.05% of the mass. 18.4 cm (7 1/4 in.) 3.4 Composition 1L 0.0625% of the mass. 18.4 cm (7 1/4 in.) four

[087] As can be seen from table 7, the suspension obtained using the compositions 1D-1I and 1K, show larger sizes of sediment cone than the suspension obtained using the composition 1A (comparative). They also set more quickly than composition 1A (comparative), which indicates that suspensions containing compositions 1D-1I and 1K had better flowability than a suspension containing composition 1A.

[088] In addition, in order to compare the size of the cone sediment for these suspensions, the time until 50% hydration was reached while setting the suspensions at the same rate. The temperature profiles of the suspension were measured using software, as will be understood by a person of ordinary skill in the art.

[089] This additional study was carried out to confirm that the cone sedimentation tests were correct, in particular to illustrate that the large cone precipitation observed in the case of suspensions containing pre-gelatinized partially hydrolyzed starches obtained according to embodiments of the present invention resulted from an improved fluidity compared with composition 1A (comparative), rather than slow hydration.

[090] The composition 1H, obtained using 2% of the mass. alum and 0.3% of the mass. tartaric acid, effectively hydrolyzed starch to a low viscosity and had less effect on the hydration rate, since tartaric acid and alum have the opposite effect on the hydration rate.

[091] FIG. 3 is a graph of temperature versus time showing the hydration rate at a given temperature increase (TRS). Compositions 1F containing 0.05% and 0.0625% of the retarder, respectively, hydrate faster or at the same rate as composition 1A (comparative).

[092] As shown in FIG. 3, composition 1L, containing 0.0625% of the mass. retarder, had the same hydration rate as composition 1A (comparative). The size of the cone precipitation when applying the composition 1L containing 0,065% of the mass. setting retarder, was 18.415 cm (7 1/4 inches) and was significantly larger than in the case of composition 1A.

[093] The results suggest that the large cone sedimentation observed when using suspensions containing pre-gelatinized partially hydrolyzed starches obtained according to embodiments of the present invention were due to high fluidity and not slower setting. In addition, the pre-gelatinized partially hydrolyzed starches obtained according to the embodiments of the present invention will make it possible to obtain wall plates using less water without compromising fluidity.

EXAMPLE 4

[094] The present example illustrates the strength of gypsum discs prepared using suspensions containing compositions 1A (comparative), 1D-1I and 1K. Strength was evaluated based on the compression test described herein.

[095] In preparation for the test, suspensions were prepared with each of compositions 1A (comparative), 1D-1I, and 1K-1L in an amount of 2 wt%, the parameters are shown in Table 4 above.

[096] To obtain gypsum discs with a final density of 29 pounds / cubic. ft (approximately 465 kg / m ³ ), a water / plaster ratio (WSR) of 100 and air foam were used. Starch was weighed and added to a dry mixture containing plaster and a heat-resistant setting accelerator. Water, a 10% sodium trimetaphosphate solution, dispersant and setting retarder were weighed into the mixing bowl of a Hobart mixer. The dry mixture was poured into the mixing bowl of the mixer, which can be purchased as an N50 5-Quart mixer at Hobart (Troy, Ohio), soaked for 10 seconds and mixed at a speed of II for 30 seconds. To obtain the foam, a 0.5% Hyonic® PFM-33 Soap Solution (HUIC) (prepared by GEO® Specialty Chemicals, Ambler, PA) was prepared and then mixed with air to give air foam. The specified air foam was added to the suspension using a foam generator. The foam generator was operated at a speed sufficient to provide the required slab density of 29 lb / cc. ft (approximately 465 kg / m ³ ). After adding the foam, the suspension was immediately poured into a place located just above the upper holes of the molds. Excess scraped off immediately after setting the plaster. Molds were sprayed with mold release lubricant (WD-40 ™). The resulting disks had a diameter of 10.16 cm (4 inches) and a thickness of 1.27 cm (0.5 inches).

[097] After the discs solidified, they were removed from the mold and then dried at 110 ° F (43 ° C) for 48 hours. After removal from the oven, the disks were allowed to cool at room temperature for 1 hour. Compression strength was measured using a material testing system, which can be purchased as a SATEC ™ E / M system from MTS Systems Corporation (Eden Prairie, Minnesota). The load was applied continuously and without impact at a speed of 0.04 in / min (about 0.1 cm / min) (at a constant speed in the range of 15 to 40 psi / s (from about 103 to about 276 kPa / s)). The results are shown below in table 8.

Table 8

Composition Compressive Strength (PSI @ 29lb / ft)
(kPa @ 465 kg / m ³ ) Composition 1A 396
(about 2730) Composition 1D 439
(about 3030) Composition 1E 388
(about 2680) Composition 1F 476
(approximately 3280) Composition 1G 419
(about 2890) Composition 1H 417
(about 2880) Composition 1I 455
(about 3140) Composition 1K 426
(about 2940)

[098] As can be seen from table 8, obtained with the use of foam discs containing compositions 1D-1I and 1K, had compressive strength comparable to disks containing composition 1A (comparative), which indicates that pre-gelatinized partially hydrolyzed starches allow reduce water consumption while maintaining its ability to increase strength. The required compressive strength of the disc samples is approximately 400 psi (approximately 2760 kPa). This strength is necessary so that the plate can be processed properly without it falling apart.

[099] It is intended that the use of the terms in the singular, the term “at least one” and similar terms in the context of the description of the present invention (especially in the context of the following claims) (for example, in relation to acids, starches or other components or elements ) includes nouns in both the plural and the singular, unless otherwise indicated in this document or is clearly contrary to the context. The use of the term “at least one” followed by a list of one or more elements (eg, “at least one of A and B”) is intended to mean one element selected from the listed elements (A or B) or any combination of two or more than the listed items (A and B), unless otherwise indicated or clearly contrary to context. The terms “consisting of”, “having”, “including” and “comprising” are meant to be non-limiting terms (ie, mean “including, but not limited to”), unless otherwise indicated. In this document, casting ranges of values merely serves as an expedited method of listing individually each individual value falling within a given range, unless otherwise indicated herein, each individual value being included in the description of the invention as if it were individually cited in this document. All methods described herein can be carried out in any suitable order, unless otherwise indicated or otherwise clearly contrary to the context. In this document, the use of any and all examples or a typical expression (for example, “such as”) is intended merely to better illustrate the invention and does not impose a limitation on the scope of the invention, unless stated otherwise. No expression in the description of the invention should be construed as an indication that any undeclared element is essential for the practical implementation of the present invention.

Preferred embodiments of the invention are described herein, including the best method known to the inventors for implementing the invention. Variations of these preferred embodiments of the invention may become apparent to those of ordinary skill in the art after reading the above description. The inventors expect experienced professionals to use such variations as necessary, and the inventors suggest that the present invention will be practiced in a different way than, in particular, described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter set forth in the claims appended hereto in accordance with applicable law. In addition, the invention includes any combination of the elements described above in all possible variations thereof, unless otherwise indicated herein or otherwise clearly contradicts the context.

Claims (16)

1. A method of obtaining pregelatinized, partially hydrolyzed starch, including: (a) mixing at least water and starch neprezhelatinizirovannogo acid value characterized by pK _a from 3 to 6, which substantially does not form chelates with calcium ions to form a wet starch-containing precursor with a moisture content of 8% by weight. up to 25% of the mass .; (b) feeding said wet starch precursor to the extruder; and (c) pre-gelatinization and acid modification of said wet starch in an extruder at a head temperature of 150 ° C (300 ° F) to 210 ° C (410 ° F), moreover, pregelatinized, partially hydrolyzed starch has a gelatinization degree of at least 70%, and pregelatinized, partially hydrolyzed starch has a viscosity in cold water (10% solid phase, 25 ° C.) of 10 Brabender units (BU) to 120 BU. 2. The method according to p. 1, characterized in that the acid, which essentially does not form chelates with calcium ions, includes alum. 3. The method according to p. 1 or 2, characterized in that to obtain the specified wet starch-containing precursor substance in the mixture include tartaric acid. 4. The method according to p. 1, characterized in that the method does not include the stage of purification and neutralization to obtain pregelatinized acid-modified starch. 5. A method of manufacturing a plate, including: (a) obtaining pre-gelatinized partially hydrolyzed starch by mixing at least water, non-gelatinized starch and acid to obtain a wet starch-containing precursor substance with a moisture content of 8% by weight. . to 25 wt%, wherein said acid is an acid, characterized by the pK _a value of from 3 to 6, which substantially does not form chelates with calcium ions; (b) feeding said wet starch precursor to the extruder; and pregelatinization and acid modification of wet starch in a die extruder at a temperature of from 150 ° C (300 ° F) to 210 ° C (410 ° F), the pregelatinized, partially hydrolyzed starch having a gelatinization degree of at least 70%, and the pregelatinized , partially hydrolyzed starch has a viscosity in cold water (10% solids, 25 ° C) from 10 Brabender units (BU) to 120 BU; (c) mixing said pregelatinized and partially hydrolyzed starch with at least water and gypsum to form a slurry; (d) placing the suspension between the first cladding sheet and the second cladding sheet to obtain a wet prefabricated structure; (e) cutting a wet prefabricated structure to form a slab; and (f) drying the stove. 6. The method according to p. 5, characterized in that the suspension further comprises sodium trimetaphosphate.

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