Continuous process for preparing flexible porous soluble solid sheet articles

Abstract

The present invention relates to a continuous process for preparing a flexible porous soluble solid sheet article.

Description

Technical Field

[0001] The present invention relates to a continuous method for preparing flexible porous soluble solid sheet products. Background Art

[0002] Soluble porous solid sheet products have been disclosed that contain a water-soluble polymer structuring agent and a surfactant or other components. However, existing methods for preparing these soluble porous solid structures have low optimal cost, manufacturing rate, and product variability parameters. In particular, drum drying has been used to manufacture flexible porous soluble solid sheets. Although it can provide the desired properties for such solid sheets, the manufacturing rate is rather limited, for example, 5 kg to 10 kg of product per drum per hour. On the other hand, continuous belt-based methods have been developed for manufacturing flexible porous soluble solid sheets to achieve high manufacturing rates. However, the pore size distribution in the flexible porous soluble solid sheets obtained in current belt-based continuous methods is not as uniform as that in drum drying. Additionally, current drum drying methods can prepare relatively thin sheets (e.g., about 1 mm), but there are challenges in manufacturing thick solid sheets. In summary, there is a desire for thick solid sheets with a uniform porous structure, but it is difficult to prepare such thick solid sheets by drum drying or existing belt drying methods.

[0003] Furthermore, it is known that multilayer sheets can contain a juice or paste between adjacent layers to provide additional benefits. In the case of multilayer sheets containing a juice or paste, the pore size of the porous solid structure needs to be within a preferred range to balance the dissolution and leakage of the juice / paste. In particular, if the pore size is too large, the juice / paste may leak out of the multilayer sheet during storage, while if the pore size is too small, the dissolution performance may not be desired.

[0004] Therefore, there is still a need for a method for producing desired flexible porous soluble solid sheet products that can be manufactured within desired cost and rate parameters. Additionally, there is a need for a method to produce flexible porous soluble solid sheet products with a faster drying time and having a desired uniform consistency and preferred pore size in the open-cell foam of the flexible porous soluble solid sheet products. Summary of the Invention

[0005] The present invention relates to a continuous method for preparing flexible porous soluble solid sheet products. In particular, the present invention relates to a continuous method for preparing sheet products, the continuous method comprising the following steps:

[0006] a) preparing a wet premix containing a water-soluble polymer and a surfactant and having a viscosity of 1,000 cps to 25,000 cps measured at 40 °C and 1 s -1 ;

[0007] b) Inflate the wet premix to form an inflated wet premix having a density in the range of 0.05 g / ml to 0.5 g / ml;

[0008] c) Shape the inflated wet premix into a sheet having a top side and a bottom side; and

[0009] d) Dry the shaped inflated wet premix sheet on a conveyor belt, wherein the bottom side of the formed sheet contacts the conveyor belt,

[0010] wherein the conveyor belt is configured to sequentially pass through a plurality of heating zones with heating temperatures in the range of 70 °C to 200 °C; wherein the plurality of heating zones includes a first heating zone and a second heating zone, and the second heating zone is located downstream of the first heating zone;

[0011] wherein the first heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a first top heating temperature (T t1 ) and a first bottom heating temperature (T b1 ) for a first heating duration of 0.01 minutes to 20 minutes; wherein the second heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a second top heating temperature (T t2 ) and a second bottom heating temperature (T b2 ) for a second heating duration of 0.01 minutes to 20 minutes; and

[0012] wherein T b1 >T t1 ; T b1 >T b2 ; and T t1 <T t2 .

[0013] In some embodiments, the first top heating temperature (T t1 ) is in the range of 70 °C to 160 °C; the first bottom heating temperature (T b1 ) is in the range of 80 °C to 190 °C; the second top heating temperature (T t2 ) is in the range of 100 °C to 200 °C; and the second bottom heating temperature (T b2 ) is in the range of 70 °C to 170 °C.

[0014] In some embodiments, T t1 is in the range of 80 °C to 150 °C, preferably 80 °C to 140 °C, more preferably 90 °C to 120 °C, for example 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or any range therebetween; wherein T b1In the range of 90 °C to 170 °C, preferably 100 °C to 160 °C, more preferably 110 °C to 140 °C, for example 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C or any range therebetween; wherein T t2 In the range of 110 °C to 190 °C, preferably 120 °C to 180 °C, more preferably 130 °C to 160 °C, for example 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C or any range therebetween; and wherein T b2 In the range of 70 °C to 150 °C, preferably 70 °C to 120 °C, more preferably 70 °C to 110 °C, for example 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C or any range therebetween. Preferably, T b2 ≤T t2 .

[0015] In some embodiments, the plurality of heating zones further includes a third heating zone located downstream of the second heating zone, and wherein the conveyor belt is configured to pass through the third heating zone; wherein the third heating zone is configured to simultaneously heat the top and bottom sides of the formed sheet at a third top heating temperature (T t3 ) and a third bottom heating temperature (T b3 ) for a third heating duration of 0.01 minutes to 20 minutes; and wherein T b2 >T b3 ; T t3 >T t2 ; and T b3 <T t3 .

[0016] In some embodiments, T t3 is in the range of 120 °C to 200 °C, preferably 130 °C to 190 °C; and wherein T b3 is in the range of 70 °C to 150 °C, preferably 70 °C to 120 °C.

[0017] In some embodiments, the plurality of heating zones in total includes 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or more heating zones, wherein the nth heating zone is configured to simultaneously heat the top and bottom sides of the formed sheet at an nth top heating temperature (T tn ) and an nth bottom heating temperature (T bn ), and wherein T bn ≥T b(n+1) ; and T tn ≤T t(n+1). Preferably, the plurality of heating zones includes from 0.1 to 5 (e.g., 0.2, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or any range therebetween) heating zones per meter of conveyor belt.

[0018] In some embodiments, the first heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or the second heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or the third heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or the total heating duration in the plurality of heating zones is from 0.05 minutes to 30 minutes, preferably from 0.1 minutes to 20 minutes, more preferably from 0.15 minutes to 15 minutes.

[0019] In some embodiments, the formed and inflated wet premix sheet is characterized by a thickness in the range of 0.5 mm to 20 mm, preferably 0.8 mm to 15 mm, more preferably 1 mm to 10 mm, still more preferably 1.2 mm to 8 mm, most preferably 1.4 mm to 6 mm, such as 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm or any range therebetween. In a preferred embodiment, the formed sheet is characterized by a thickness in the range of 1.5 mm to 20 mm, preferably 1.5 mm to 15 mm, more preferably 1.5 mm to 10 mm, still more preferably 1.5 mm to 8 mm, most preferably 1.5 mm to 6 mm.

[0020] In some embodiments, the wet premix comprises from 3% to 70%, preferably from 4% to 50%, more preferably from 5% to 40% by total weight of the wet premix of the water-soluble polymer; and / or the wet premix comprises from 1% to 40%, preferably from 2% to 35%, more preferably from 5% to 30% by total weight of the wet premix of the surfactant; and / or the density of the inflated wet premix is in the range of 0.08 g / ml to 0.4 g / ml, preferably 0.1 g / ml to 0.35 g / ml; and / or the wet premix is characterized by a solids content in the range of 15% to 70%, preferably 20% to 50%, more preferably 25% to 45% by weight of the wet premix; and / or the wet premix is characterized by a viscosity, as measured at 40 °C and 1 s -1 in the range of 3,000 cps to 24,000 cps, preferably 5,000 cps to 23,000 cps, more preferably 10,000 cps to 20,000 cps.

[0021] In some embodiments, the plurality of heating zones are configured to heat the top side of the formed sheet by convective heating and the bottom side of the formed sheet by conductive heating.

[0022] In another aspect, the present invention relates to a belt drying system for preparing a sheet product, wherein the system comprises:

[0023] A conveyor belt configured to convey a wet premix and form the wet premix into a sheet having a top side and a bottom side,

[0024] A plurality of heating members configured to dry the wet premix by heating to form the sheet, and

[0025] A heat source configured to supply heat to the plurality of heating members,

[0026] wherein the conveyor belt is configured to sequentially pass through the plurality of heating members with heating temperatures in the range of 70°C to 200°C;

[0027] which includes a first heating member and a second heating member, the second heating member being located downstream of the first heating member;

[0028] wherein the first heating member is configured to simultaneously heat the top side and the bottom side of the formed sheet at a first top heating temperature (T t1 ) and a first bottom heating temperature (T b1 ) for a first heating duration of 0.01 minutes to 20 minutes; wherein the second heating member is configured to simultaneously heat the top side and the bottom side of the formed sheet at a second top heating temperature (T t2 ) and a second bottom heating temperature (T b2 ) for a second heating duration of 0.01 minutes to 20 minutes; and

[0029] wherein T b1 >T t1 ; T b1 >T b2 ; and T t1 <T t2 .

[0030] In yet another aspect, the present invention relates to a flexible porous soluble solid sheet product comprising a water-soluble polymer and a surfactant, wherein the solid sheet product is characterized in that: (i) the thickness is in the range of 1.5 mm to 20 mm; and (ii) the percentage of open pores is 80% to 99.9%; (iii) the overall average pore size is 100 μm to 1000 μm; and (iv) the standard deviation of the overall average pore size is 10 μm to 250 μm, wherein the solid sheet product has opposite top and bottom surfaces, and the top surface has a surface average pore size greater than 100 μm; wherein the solid sheet product includes a top region adjacent to the top surface, a bottom region adjacent to the bottom surface, and an intermediate region between the top region and the bottom region; wherein the top region, the intermediate region, and the bottom region have the same thickness, and each of the top region, the intermediate region, and the bottom region is characterized by an average pore size; and wherein the ratio of the average pore size in the bottom region to the average pore size in the top region is 0.6 to 1.5. Preferably, the solid sheet product according to the present disclosure can be prepared by the method according to the present disclosure.

[0031] In some embodiments, the solid sheet product is characterized in that the thickness is 1.5 mm to 20 mm, preferably 1.5 mm to 15 mm, more preferably 1.5 mm to 10 mm, still more preferably 1.5 mm to 8 mm, most preferably 1.5 mm to 6 mm, such as 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, or any range therebetween.

[0032] In some embodiments, the solid sheet product is characterized in that the percentage of open pores is 85% to 99.9%, preferably 90% to 99.9%.

[0033] In some embodiments, the solid sheet product is characterized in that the overall average pore size is 20 μm to 600 μm, preferably 50 μm to 500 μm, more preferably 100 μm to 400 μm, such as 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm or any range therebetween.

[0034] In some embodiments, the solid sheet product is characterized in that the standard deviation of the overall average pore size is from 20 μm to 250 μm, preferably from 30 μm to 250 μm, more preferably from 50 μm to 200 μm, such as 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm or any range therebetween.

[0035] Advantageously, the continuous method according to the present disclosure can produce more than 200 kg of product per hour, which is 20 to 40 times that of the drum drying method.

[0036] Further advantageously, the continuous method according to the present disclosure can produce thick and uniform solid sheet products. Preferably, the solid sheet product is characterized in that: (i) the thickness is in the range of 1.5 mm to 20 mm; and (ii) the percentage of open cell content is from 80% to 99.9%; (iii) the overall average pore size is from 100 μm to 1000 μm; and (iv) the standard deviation of the overall average pore size is from 10 μm to 250 μm.

[0037] Unexpectedly, it has been found that the solid sheet products produced by the continuous method disclosed herein produce a uniform and consistent structure in the open cell foam of the product. In addition, the pore size of the open cell foam of the solid sheet product can be within a preferred range to ensure a better balance between dissolution and leakage of the juice / paste loaded within the multi-layer solid sheet product. Description of the Drawings

[0038] Figure 1 is an exemplary embodiment of an apparatus for practicing the continuous method according to the present disclosure.

[0039] Figure 2 Shows a plurality of heating components in an exemplary system of belt drying according to the present disclosure.

[0040] Figure 3 Shows the pore size distribution across the entire thickness of solid sheet products produced by various methods including drum drying, conventional belt drying, and stepwise belt drying. Detailed Description

[0041] In all embodiments of the present invention, unless otherwise specifically stated, all percentages are by weight of the total composition. Unless otherwise specifically stated, all ratios are weight ratios. All ranges are inclusive of the end values and combinable. The number of significant figures represents neither a limitation on the quantity shown nor on the precision of the measurement. All numerical values should be understood to be modified by the word "about" unless otherwise specifically indicated. Unless otherwise indicated, all measurements are understood to be made at 25 °C and under ambient conditions, where "ambient conditions" means conditions at about one atmosphere and at about 50% relative humidity. Unless otherwise indicated, all such weights related to the listed ingredients are based on the active substance level and do not include carriers or by-products that may be included in commercially available materials.

[0042] Definition

[0043] Flexible porous soluble solid structure articles may be referred to herein as "articles" or "soluble articles". All references are intended to denote flexible soluble porous solid structure articles.

[0044] As used herein, the term "flexible" refers to the ability of the article to withstand stress without breaking or significantly rupturing when the article is bent 90° along a centerline perpendicular to its longitudinal direction. Preferably, such articles can undergo significant elastic deformation and are characterized by a Young's modulus of no greater than 5 GPa, preferably no greater than 1 GPa, more preferably no greater than 0.5 GPa, and most preferably no greater than 0.2 GPa.

[0045] As used herein, the term "soluble" refers to the ability of the article to completely or substantially dissolve in a sufficient amount of deionized water within eight (8) hours at 20 °C and atmospheric pressure without any agitation, leaving less than 5% by weight of undissolved residue.

[0046] As used herein, the term "solid" refers to the ability of the article to substantially maintain its shape (i.e., there is no visible change in its shape) at 20 °C and atmospheric pressure when the article is unrestricted and when no external force is applied to it.

[0047] As used herein, the term "sheet" refers to a non-fibrous structure having a three-dimensional shape, i.e., having a thickness, a length, and a width, and both the length-to-thickness aspect ratio and the width-to-thickness aspect ratio are at least about 5:1, and the length-to-width ratio is at least about 1:1. Preferably, both the length-to-thickness aspect ratio and the width-to-thickness aspect ratio are at least about 10:1, more preferably at least about 15:1, and most preferably at least about 20:1; and the length-to-width aspect ratio is preferably at least about 1.2:1, more preferably at least about 1.5:1, and most preferably at least about 1.618:1.

[0048] As used herein, the term "continuous" method refers to a manufacturing method in which the production of a product is carried out without a defined starting or ending point. The term "batch" method refers to a manufacturing method in which a specific quantity of goods is prepared in a single production run. It has a defined starting and ending point, meaning that once the batch has been produced, the process is complete.

[0049] As used herein, the term "bottom surface" refers to the surface of the flexible, porous, soluble solid sheet product of the present invention on which the sheet that is in immediate contact with the aerated wet premix during the drying step is placed, while the term "top surface" refers to the surface of the sheet product opposite the bottom surface. Additionally, such solid sheet products can be divided along their thickness into three (3) regions, including a top region adjacent to its top surface, a bottom region adjacent to its bottom surface, and a middle region located between the top and bottom regions. The top, middle, and bottom regions have equal thicknesses, i.e., each has a thickness of approximately 1 / 3 of the total thickness of the sheet product.

[0050] As used herein, the term "open-cell foam" or "open-cell pore structure" refers to a polymer-containing solid interconnected matrix that defines a network of spaces or cells that contain a gas, typically a gas (such as air), and the foam structure does not collapse during the drying process, thereby maintaining the physical strength and cohesiveness of the solid. The interconnectivity of the structure can be described by the percentage of open cells, which is measured by Test 3 disclosed below.

[0051] As used herein, the term "water-soluble" refers to the ability of a material to completely dissolve or disperse in water without leaving visible solids or forming a distinct separated phase when at least about 25 grams, preferably at least about 50 grams, more preferably at least about 100 grams, and most preferably at least about 200 grams of the sample material is placed in one liter (1 L) of deionized water at 20 °C and stirred thoroughly at atmospheric pressure.

[0052] As used herein, the term "aerating" refers to a method of introducing a gas into a liquid or paste composition by mechanical and / or chemical means.

[0053] As used herein, the term "heating direction" refers to the direction along which a heat source applies thermal energy to a product, which results in a temperature gradient in such product that decreases from one side of such product to the other. For example, if a heat source located on one side of a product applies thermal energy to the product to create a temperature gradient that decreases from one side to the opposite side, the heating direction is considered to extend from one side to the opposite side. If both sides of such product or different parts of such product are heated simultaneously without an observable temperature gradient across such product, the heating is carried out in a non-directional manner and there is no heating direction.

[0054] As used herein, the term "substantially opposite to" or "substantially offset from" means an offset angle of 90° or greater between two directions or two lines.

[0055] As used herein, the term "substantially aligned" or "substantially in alignment" means an offset angle of less than 90° between two directions or two lines.

[0056] As used herein, the term "aging" refers to the process of holding an inflated wet mixture or premix for a period of time without further introduction of a substantial amount of gas. Preferably, aging can be carried out under conditions substantially free of mechanical energy input and / or substantially free of heat input. More preferably, aging can be carried out at ambient temperature without any agitation.

[0057] The term "substantially free of" means that the indicated material is present at a very low level, not intentionally added to the composition or product, or preferably present in such composition or product at a level undetectable by analytical methods. It can include such compositions or products in which the indicated material is only an impurity in one or more of the materials intentionally added to such composition or product.

[0058] The test methods disclosed in the test methods section of this application are applied to determine the corresponding parameter values of the applicant's invention.

[0059] Unless otherwise specified, all percentages and ratios are by weight. Unless otherwise specified, all percentages and ratios are based on the total composition.

[0060] It should be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range falling within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

[0061] Manufacturing method

[0062] An article can be prepared by a continuous process that includes: a) preparing a composition comprising a water-soluble polymer and a surfactant and having a viscosity at 40 °C and 1 s -1a wet premix having a viscosity of from 1,000 cps to 25,000 cps as measured below; b) inflating the wet premix to form an inflated wet premix having a density of from 0.05 g / ml to 0.5 g / ml; c) forming the inflated wet premix into a sheet having a top side and a bottom side, such as by extruding the inflated wet premix; and d) drying the formed inflated wet premix sheet on a conveyor belt, wherein the bottom side of the formed sheet contacts the conveyor belt.

[0063] A. Preparation of the premix

[0064] Figure 1 Depicts an exemplary embodiment of an apparatus for practicing a continuous method for generating an article. As Figure 1 shown, in a continuous manufacturing apparatus 1, solids of interest are mixed in a premixing tank 3. A premix is typically prepared by mixing solids of interest, which include surfactants, dissolved water-soluble polymers, optional plasticizers, and other optional ingredients.

[0065] In one embodiment, a mechanical mixer can be used to form the premix. Mechanical mixers that can be used herein include, but are not limited to, pitched blade mixers or MAXBLEND mixers (Sumitomo Heavy Industries).

[0066] To add ingredients to the premix, it is contemplated that the polymer is ultimately dissolved in the presence of water, surfactant, optional active substances, optional plasticizers, and any other optional ingredients, including stepwise processing by premixing portions of any combination of the ingredients.

[0067] B. Optionally continue heating the premix

[0068] Optionally, prior to the inflation process, the premix is immediately preheated at a temperature above ambient temperature but below any temperature that would cause degradation of the components. In one embodiment, the premix is maintained at above about 40 °C and below about 99 °C, in another embodiment, above about 50 °C and below about 95 °C, in another embodiment, above about 60 °C and below about 90 °C. In one embodiment, when the viscosity of the premix at ambient temperature is from about 1000 cps to about 20,000 cps, optional continuous heating is utilized prior to the inflation step. In additional embodiments, additional heat is applied during the inflation process to attempt to maintain an elevated temperature during inflation. This can be achieved via conductive heating from one or more surfaces, injection of steam, or other processing means.

[0069] C. Inflation of the premix

[0070] In one embodiment, the aeration of the premix can be achieved by introducing a gas into the premix with mechanical mixing energy, but it can also be achieved via chemical means to form an aerated mixture. As Figure 1 shown, the aeration of the premix is achieved by an aeration unit 5. The aeration can be accomplished by any suitable mechanical processing means, including but not limited to: (i) batch tank aeration via mechanical mixing (including planetary mixers or other suitable mixing vessels), or (ii) semi - continuous or continuous aerators (pressurized and non - pressurized) used in the food industry, or (iii) spray - drying the processed mixture to form aerated beads or granules, which can be compressed with heat, for example, in a mold to form a porous solid.

[0071] In another embodiment, aeration with a chemical foaming agent can be used by in - situ gas formation (via a chemical reaction of one or more components, including the formation of carbon dioxide (CO2(g)) through an effervescent system).

[0072] In a specific embodiment, it has been found that the article can be prepared in a continuous pressurized aerator routinely used in the food industry for the production of marshmallows. Suitable continuous pressurized aerators include Morton mixers (Morton Machine Co., Motherwell, Scotland), Oakes continuous automatic mixers (E.T. Oakes Corporation, Hauppauge, New York), Fedco continuous mixers (The Peerless Group, Sidney, Ohio), Mondo (Haas - Mondomix B.V., Netherlands), Aeros (Aeros Industrial Equipment Co., Ltd., Guangdong Province, China), and Preswhip (Hosokawa Micron Group, Osaka, Japan). The continuous mixer can be used to homogenize or aerate the slurry to produce a highly uniform and stable foam structure with uniform bubble size. The unique design of the high - shear rotor / stator mixing head can produce a uniform bubble size in the layer of open - cell foam.

[0073] D. Formation of the inflated wet premix

[0074] As Figure 1As can be seen, the formation of the aerated wet premix is accomplished by extruding the aerated mixture through an extrusion nozzle 7 onto a conveyor belt 9 or a screen, which conveyor belt or screen comprises any non-interacting or non-sticking material, such as solid metal materials, flexible plastic materials including infrared-transparent materials, and combinations thereof. Non-limiting examples of solid metal materials include stainless steel. Non-limiting examples of flexible plastic materials include, but are not limited to, materials such as HDPE, polycarbonate, rubber, LDPE, and fiberglass. Non-limiting examples of infrared-transparent materials include, but are not limited to

[0075] After extrusion, the aerated wet premix forms one or more sheets. In one embodiment, a sheet 11 forms an article having a thickness of from about 0.5 mm to about 20 mm. In another embodiment, the article has a thickness of from about 1 mm to 2 mm. In another embodiment, two or more sheets 11 are combined to form an article having a final thickness of from about 2 mm to about 10 mm. Extruding thinner sheets and then combining the thinner sheets to form the article allows for a faster drying time for each individual sheet. The sheets can be combined by any means known in the art, examples of which include, but are not limited to, chemical means, mechanical means, and combinations thereof. The combination of the sheets allows two or more sheets to be stacked on top of each other.

[0076] The wet density of the aerated premix ranges from about 0.05 g / cm 3 to about 0.5 g / cm 3 , from about 0.10 g / cm 3 to about 0.45 g / cm 3 , from about 0.20 g / cm 3 to about 0.40 g / cm 3 , and from about 0.25 g / cm 3 to about 0.35 g / cm 3 .

[0077] E. Gradually dry the formed inflated wet premix

[0078] The drying of the shaped aerated wet premix according to the present application is a stepwise process. In particular, the conveyor belt is configured to sequentially pass through a plurality of heating zones having heating temperatures in the range of 70°C to 200°C; wherein the plurality of heating zones includes a first heating zone and a second heating zone, the second heating zone being located downstream of the first heating zone. More specifically, the first heating zone is configured to have a first top heating temperature (T t1 ) and a first bottom heating temperature (T b1)Simultaneously heat the top and bottom sides of the formed sheet at a first heating duration of from 0.01 minute to 20 minutes; wherein the second heating zone is configured to simultaneously heat the top and bottom sides of the formed sheet at a second top heating temperature (T t2 ) and a second bottom heating temperature (T b2 ) for a second heating duration of from 0.01 minute to 20 minutes; and wherein T b1 >T t1 ; T b1 >T b2 ; and T t1 <T t2 .

[0079] As Figure 1 shown, drying of the formed aerated wet premix can be accomplished by any suitable drying environments 13 and 14, including but not limited to: (i) drying chambers, including chambers having controlled temperature and pressure or atmospheric conditions; (ii) ovens, including non-convective or convective ovens having controlled temperature and optional humidity; (iii) trolley / tray dryers; (iv) multi-stage series dryers; (v) impingement ovens; (vi) rotary ovens / dryers; (vii) series roasters; (viii) rapid high heat transfer ovens and dryers; (ix) double-chamber roasters; (x) conveyor dryers; (xi) vacuum drying chambers; (xii) air distribution plates; (xiii) venturi dryers, and combinations thereof. The drying environments 13 and 14 can provide different heating temperatures.

[0080] In one embodiment, the drying environments 13 and 14 are selected from the group consisting of one or more drying chambers, convective ovens, multi-layer ovens, trolley / tray dryers, multi-stage series dryers, impingement oven / dryers, rotary oven / dryers, series roasters, rapid high heat transfer ovens and dryers, double-chamber roasters, conveyor dryers, vacuum drying chambers, and combinations thereof, such that the drying environment is between 100 °C and 150 °C.

[0081] Other suitable drying environments include "volume heating" techniques using high-frequency electromagnetic fields, such as microwave drying and infrared drying. Using these techniques, energy is transferred electromagnetically through the aerated wet premix, rather than by conduction or convection.

[0082] In some embodiments, the first top heating temperature (T t1 ) in the drying environment 13 is in the range of 70 °C to 160 °C; the first bottom heating temperature (T b1 ) in the drying environment 13 is in the range of 80 °C to 190 °C; the second top heating temperature (T t2) within the range of 100 °C to 200 °C; and the second bottom heating temperature (T b2 ) within the range of 70 °C to 170 °C.

[0083] In some embodiments, T t1 within the range of 80 °C to 150 °C, preferably 80 °C to 140 °C; wherein T b1 within the range of 90 °C to 170 °C, preferably 100 °C to 160 °C; wherein T t2 within the range of 110 °C to 190 °C, preferably 120 °C to 180 °C; and wherein T b2 within the range of 70 °C to 150 °C, preferably 70 °C to 120 °C; and wherein T b2 ≤T t2 .

[0084] In some embodiments, the plurality of heating zones further includes a third heating zone, and wherein the conveyor belt is configured to pass through the third heating zone; wherein the third heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a third top heating temperature (T t3 ) and a third bottom heating temperature (T b3 ) for a third heating duration of 0.01 minutes to 20 minutes.

[0085] In some embodiments, when the third heating zone is located downstream of the second heating zone, T b2 ≥T b3 ; T t2 ≤T t3 ; and T b3 ≤T t3 .

[0086] In some embodiments, when the third heating zone is located downstream of the first heating zone and upstream of the second heating zone, T b1 ≥T b3 ≥T b2 ; T t1 ≤T t3 ≤T t2 .

[0087] In some embodiments, when the third heating zone is located upstream of the first heating zone, T b3 ≥T b1 ; T t3 ≤T t1 ; and T b3 ≥T t3 .

[0088] In some embodiments, T t3in the range of 90 °C to 200 °C; and wherein T b3 in the range of 70 °C to 180 °C.

[0089] In some embodiments, the first heating duration is from 0.1 minute to 10 minutes, preferably from 0.15 minute to 8 minutes; and / or the second heating duration is from 0.1 minute to 10 minutes, preferably from 0.15 minute to 8 minutes; and / or the third heating duration is from 0.1 minute to 10 minutes, preferably from 0.15 minute to 8 minutes; and / or the total heating duration in the plurality of heating zones is from 0.3 minute to 30 minutes, preferably from 0.5 minute to 20 minutes, more preferably from 0.6 minute to 15 minutes.

[0090] In an exemplary system for stepwise belt drying as Figure 2 shown, system 2 includes a first heating zone 21 and a second heating zone 23. In the first heating zone 21, hot air is introduced into a first top air distribution plate 215 and a first bottom air distribution plate 217 from a first top inlet 211 and a first bottom inlet 213, respectively, and then applied as hot air jets onto the top surface and the bottom surface of the belt (as shown by the arrows). In the second heating zone 23, hot air is introduced into a first top air distribution plate 235 and a first bottom air distribution plate 237 from a first top inlet 231 and a first bottom inlet 233, respectively, and then applied as hot air jets onto the top surface and the bottom surface of the belt (as shown by the arrows). In particular, the air distribution plates 215, 217, 235, and 237 each include a plurality of holes through which the hot air jets can be ejected onto the sheet formed on the belt or onto the belt itself for conductive heating and convective heating of the foam. Then, a dried solid sheet 25 is formed on the belt after drying.

[0091] The resulting article also has open-cell foam with an open-cell percentage of from about 80% to about 100%. Unexpectedly, it has been found that articles produced by a continuous process have uniformity in the upper, middle, and lower regions of the open-cell foam.

[0092] The solid sheet product may include a top region adjacent to the top surface, a bottom region adjacent to the bottom surface, and an intermediate region between the top region and the bottom region; wherein the top region, the intermediate region, and the bottom region have the same thickness, and each of the top region, the intermediate region, and the bottom region is characterized by an average pore size (i.e., the top average pore size, the intermediate average pore size, and the bottom average pore size). In particular, the ratio of the average pore size in the bottom region to the average pore size in the top region may be from 0.6 to 1.5, preferably from about 0.7 to about 1.4, more preferably from about 0.8 to about 1.3, and most preferably from about 0.9 to about 1.2; and / or the ratio of the average pore size in the bottom region to the average pore size in the intermediate region may be from about 0.6 to about 1.5, preferably from about 0.7 to about 1.4, more preferably from about 0.8 to about 1.3, and most preferably from about 0.9 to about 1.2; and / or the ratio of the average pore size in the intermediate region to the average pore size in the top region may be from about 0.6 to about 1.5, preferably from about 0.7 to about 1.4, more preferably from about 0.8 to about 1.3, and most preferably from about 0.9 to about 1.2.

[0093] F. Other optional steps

[0094] Other optional steps not listed above may be added at any point during or after the process. Optional ingredients may be added during any of the four processing steps described above or even after the drying process.

[0095] Additional steps that may be used in the method include cutting the resulting product into smaller sizes, piercing the product with needles, or cutting the product. The size of the product will depend on the desired dosage of the active substance (or surfactant in this case). The frequency of piercing or cutting is limited to maintain the structural integrity of the product so that it can still be handled.

[0096] The product may be further processed into a shape or form different from a flat plane or sheet. Other three-dimensional shapes may include spherical beads or balls, flowers, petals, berry shapes, and various known pasta shapes. Thus, the method may also include the step of processing the product into a three-dimensional shape.

[0097] The product may be packaged for individual consumption or in the form of multiple products. The product may be included in a gift set that supplies various types of products, including products with different compositions, products that form a series of products with other products for a desired benefit, or products not related to other products (such as a travel makeup set for use when traveling by plane).

[0098] A suitable packaging material may be selected to protect the product from accidental exposure to liquids. The packaging material may be air and / or vapor permeable, depending on the sales environment of the product.

[0099] The method may further include the step of individually packaging the article for sale as a product. The method may further include the step of packaging a plurality of articles for sale as a product. The method may further include the step of including the packaged article in a kit for sale as a product. The packaging step is carried out after the article is formed, and in one embodiment, after the article is cut to a suitable size. The article may be packaged on the same production line as the article is produced, or the article may be collected, transported or stored and then packaged at a later time.

[0100] Composition of the article

[0101] 1. Water-soluble polymer

[0102] As mentioned above, the flexible porous soluble solid sheet article of the present invention can be formed from a wet premix comprising a water-soluble polymer and a surfactant. Such water-soluble polymers can be used as film formers, structurants, and carriers for other active ingredients (e.g., surfactants, emulsifiers, builders, chelating agents, fragrances, colorants, etc.) in the resulting solid sheet article.

[0103] Preferably, the wet premix may comprise from about 3% to about 70% by weight of the premix of the water-soluble polymer, in one embodiment from about 4% to about 50% by weight of the premix of the water-soluble polymer, and in one embodiment from about 5% to about 40% by weight of the premix of the water-soluble polymer.

[0104] After drying, it is preferred that the water-soluble polymer is present in the flexible porous soluble solid sheet article of the present invention in an amount in the range of from about 5% to about 60%, preferably from about 8% to about 50%, more preferably from about 10% to about 40% (e.g., 50%, 40%, 30%, 20%, 10% or any range therebetween) based on the total weight of the solid sheet article. In a particularly preferred embodiment of the present invention, the total amount of the water-soluble polymer present in the flexible porous soluble solid sheet article of the present invention is not more than 25% based on the total weight of such articles.

[0105] Water-soluble polymers suitable for practicing the present invention can be selected from those having a weight-average molecular weight in the range of from about 5,000 Daltons to about 400,000 Daltons, more preferably from about 10,000 Daltons to about 300,000 Daltons, still more preferably from about 15,000 Daltons to about 200,000 Daltons, and most preferably from about 20,000 Daltons to about 150,000 Daltons. The weight-average molecular weight is calculated by summing the products of the average molecular weight of each polymer raw material and their respective weight percentage by weight of the total weight of the polymer present in the porous solid. The weight-average molecular weight of the water-soluble polymers used herein can affect the viscosity of the wet premix, which in turn can affect the number and size of the bubbles during the gas injection step and the pore expansion / opening results during the drying step. In addition, the weight-average molecular weight of the water-soluble polymer can affect the overall film-forming properties of the wet premix and its compatibility / incompatibility with a particular surfactant.

[0106] The water-soluble polymers of the present invention can include, but are not limited to, synthetic polymers, including polyvinyl alcohol, polyvinylpyrrolidone, polyalkylene oxides, polyacrylates, caprolactam, polymethacrylates, polymethyl methacrylate, polyacrylamides, polymethacrylamides, polydimethylacrylamide, polyethylene glycol monomethacrylate, copolymers of acrylic acid and methyl acrylate, polyurethanes, polycarboxylic acids, polyvinyl acetate, polyesters, polyamides, polyamines, polyethyleneimine, maleic acid / (acrylate or methacrylate) copolymers, copolymers of methyl vinyl ether and maleic anhydride, copolymers of vinyl acetate and crotonic acid, copolymers of vinyl pyrrolidone and vinyl acetate, copolymers of vinyl pyrrolidone and caprolactam, vinyl pyrrolidone / vinyl acetate copolymers, copolymers of anionic, cationic and amphoteric monomers, and combinations thereof.

[0107] The water-soluble polymers of the present invention can also be selected from polymers derived from natural sources, including those of plant origin, examples of which include karaya gum, tragacanth gum, gum arabic, acetylmorphine, konjac glucomannan, acacia gum, dava gum, whey protein isolate, and soy protein isolate; seed extracts, including guar gum, locust bean gum, sweetgum seeds and psyllium seeds; seaweed extracts such as carrageenan, alginate and agar; fruit extracts (pectin); those of microbial origin, including xanthan gum, gellan gum, pullulan, hyaluronic acid, chondroitin sulfate and dextran; and those of animal origin, including casein, gelatin, keratin, keratin hydrolysate, sulfo-keratin, albumin, collagen, gluten, glucagon, glutelin, zein and shellac.

[0108] Modified natural polymers can also be used as the water-soluble polymers of the present invention. Suitable modified natural polymers include, but are not limited to, cellulose derivatives such as hydroxypropyl methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, methylcellulose, hydroxypropylcellulose, ethylcellulose, carboxymethylcellulose, cellulose acetate phthalate, nitrocellulose, and other cellulose ethers / esters; and guar gum derivatives such as hydroxypropyl guar gum.

[0109] The water-soluble polymers of the present invention can include starch. As used herein, the term "starch" includes naturally occurring or modified starch. Typical natural sources of starch can include grains, tubers, roots, legumes, and fruits. More specific natural sources can include corn, peas, potatoes, bananas, barley, wheat, rice, sago, amaranth, cassava, arrowroot, canna, sorghum, and their waxy or high-amylase varieties. Natural starch can be modified by any modification method known in the art to form modified starch, including physically modified starch such as shear starch or heat-inhibited starch; chemically modified starch such as those that have been crosslinked, acetylated and organoesterified, hydroxyethylated and hydroxypropylated, phosphorylated, and inorganoesterified, their cationic, anionic, nonionic, amphoteric, and zwitterionic derivatives, and their succinate and substituted succinate derivatives; conversion products derived from any of the starches, including fluid starch or thin-boiling starch prepared by oxidation, enzymatic conversion, acid hydrolysis, heating, or acid dextrinization, products that have been heat-treated and / or sheared can also be used herein; and pregelatinized starch known in the art.

[0110] Preferred water-soluble polymers of the present invention include polyvinyl alcohol, polyvinylpyrrolidone, polyalkylene oxides, starch and starch derivatives, pullulan, gums, hydroxypropyl methylcellulose, methylcellulose, and carboxymethylcellulose. More preferred water-soluble polymers of the present invention include polyvinyl alcohol and hydroxypropyl methylcellulose.

[0111] The most preferred water-soluble polymer of the present invention is polyvinyl alcohol, which is characterized by a degree of hydrolysis in the range of about 40% to about 100%, preferably about 50% to about 95%, more preferably about 65% to about 92%, and most preferably about 70% to about 90%. Commercially available polyvinyl alcohols include those obtained from Celanese Corporation (Texas, USA) under the trade name CELVOL, including but not limited to CELVOL 523, CELVOL 530, CELVOL 540, CELVOL 518, CELVOL 513, CELVOL 508, CELVOL 504; under and POVAL TMThose with trade names obtained from Kuraray Europe GmbH (Frankfurt, Germany); and PVA 1788 (also known as PVA BP17), which is commercially available from various suppliers including Lubon Vinylon Co. (Nanjing, China); and combinations thereof. In a particularly preferred embodiment of the present invention, the flexible porous soluble solid sheet product comprises from about 10% to about 25%, more preferably from about 15% to about 23% by total weight of such product, of polyvinyl alcohol having a weight average molecular weight of from 80,000 daltons to about 150,000 daltons and a degree of hydrolysis of from about 80% to about 90%.

[0112] In addition to the polyvinyl alcohol mentioned above, a single starch or combination of starches can be used as a filler in an amount that reduces the total amount of water-soluble polymer required, provided that this helps to provide a solid sheet product having the desired structure and physical / chemical properties as described herein. However, too much starch can compromise the solubility and structural integrity of the sheet product. Accordingly, in a preferred embodiment of the present invention, it is desirable for the solid sheet product to contain no more than 20%, preferably from 0% to 10%, more preferably from 0% to 5%, and most preferably from 0% to 1% starch by weight of the solid sheet product.

[0113] 2. Surfactant

[0114] In addition to the water-soluble polymers described above, the solid sheet products of the present invention further comprise one or more surfactants. The surfactant can be used as an emulsifier during the aeration process to produce a sufficient amount of stable bubbles to form the desired OCF structure of the present invention. In addition, the surfactant can be used as an active ingredient for delivering the desired cleaning benefits.

[0115] In one embodiment of the present invention, the solid sheet product comprises one or more surfactants selected from the group consisting of: anionic surfactants, nonionic surfactants, cationic surfactants, zwitterionic surfactants, amphoteric surfactants, polymeric surfactants, or combinations thereof. Different surfactants can be selected depending on the desired application of such solid sheet products and the desired consumer benefits to be achieved. One advantage of the present invention is that the OCF structure of the solid sheet product allows for the introduction of a high surfactant content while still providing rapid dissolution. Accordingly, highly concentrated cleaning compositions can be formulated into the solid sheet products of the present invention to provide consumers with a new and superior cleaning experience.

[0116] As used herein, surfactants can include those from surfactants in the conventional sense (i.e., those that provide a foaming effect easily visible to the consumer) and emulsifiers (i.e., those that do not provide any foaming properties but are mainly used as processing aids for preparing a stable foam structure). Examples of emulsifiers used as the surfactant component herein include monoglycerides and diglycerides of glycerol, fatty alcohols, polyglycerol esters, propylene glycol esters, sorbitan esters, and other emulsifiers known or otherwise commonly used to stabilize the air interface.

[0117] The total amount of surfactant present in the solid sheet product of the present invention can be in a wide range of about 5% to about 80%, preferably about 10% to about 70%, more preferably about 30% to about 65% based on the total weight of the solid sheet product. Correspondingly, the wet premix can contain about 1% to about 40% surfactant by weight of the wet premix, in one embodiment about 2% to about 35% surfactant by weight of the wet premix, and in one embodiment about 5% to about 30% surfactant by weight of the wet premix.

[0118] In a preferred embodiment of the present invention, the solid sheet product of the present invention is a cleaning product containing about 30% to about 80%, preferably about 40% to about 70%, more preferably about 50% to about 65% of one or more surfactants based on the total weight of the solid sheet product. In this case, the wet premix can contain about 10% to about 40% surfactant by weight of the wet premix, in one embodiment about 12% to about 35% surfactant by weight of the wet premix, and in one embodiment about 15% to about 30% surfactant by weight of the wet premix.

[0119] Non-limiting examples of anionic surfactants suitable for use herein include alkyl sulfates and alkyl ether sulfates, sulfated monoglycerides, sulfonated olefins, alkyl aryl sulfonates, primary or secondary alkane sulfonates, alkyl sulfosuccinates, acyl taurates, acyl isethionates, alkyl glyceryl ether sulfonates, sulfonated methyl esters, sulfonated fatty acids, alkyl phosphates, acyl glutamates, acyl sarcosinates, alkyl sulfonates of sulfonic acid, acylated peptides, alkyl ether carboxylates, acyl lactates, anionic fluorinated surfactants, sodium lauroyl glutamate, and combinations thereof.

[0120] A class of anionic surfactants particularly suitable for the practice of the present invention includes C6-C 20 Linear alkylbenzene sulfonate (LAS) surfactants. LAS surfactants are well known in the art and can be readily obtained by sulfonating commercially available linear alkylbenzenes. Exemplary C 10 -C 20Linear alkylbenzene sulfonates include C 10 -C 20 alkali metal, alkaline earth metal or ammonium salts of linear alkylbenzene sulfonic acid, preferably C 11 -C 18 or C 11 -C 14 sodium, potassium, magnesium and / or ammonium salts of linear alkylbenzene sulfonic acid. More preferably C 12 and / or C 14 sodium or potassium salts of linear alkylbenzene sulfonic acid, and most preferably C 12 and / or C 14 sodium salts of linear alkylbenzene sulfonic acid, namely sodium dodecylbenzenesulfonate or sodium tetradecylbenzenesulfonate.

[0121] LAS provides excellent cleaning benefits and is particularly suitable for use in laundry detergent applications. It has surprisingly and unexpectedly been found in the present invention that when polyvinyl alcohol having a relatively high weight average molecular weight (e.g., from about 50,000 Daltons to about 400,000 Daltons, preferably from about 60,000 Daltons to about 300,000 Daltons, more preferably from about 70,000 Daltons to about 200,000 Daltons, most preferably from about 80,000 Daltons to about 150,000 Daltons) is used as a film-forming agent and carrier, LAS can be used as the main surfactant, i.e., present in the solid sheet product in an amount greater than 50% by weight of the total surfactant content, without adversely affecting the film-forming properties and the stability of the overall composition. Correspondingly, in a specific embodiment of the present invention, LAS is used as the main surfactant in the solid sheet product. If present, the amount of LAS in the solid sheet product of the present invention can be in the range of from about 10% to about 70%, preferably from about 20% to about 65%, more preferably from about 40% to about 60% by weight of the total weight of the solid sheet product.

[0122] Another class of anionic surfactants suitable for the practice of the present invention includes sodium trideceth sulfate (STS), which has a weight-average degree of alkoxylation in the range of from about 0.5 to about 5, preferably from about 0.8 to about 4, more preferably from about 1 to about 3, and most preferably from about 1.5 to about 2.5. Trideceth is a 13-carbon branched alkoxylated hydrocarbon which, in one embodiment, contains on average at least 1 methyl branch per molecule. The STS used in the present invention may include ST(EOxPOy)S, where EOx refers to repeating ethylene oxide units having a repeat number x in the range of from 0 to 5, preferably from 1 to 4, more preferably from 1 to 3, and POy refers to repeating propylene oxide units having a repeat number y in the range of from 0 to 5, preferably from 0 to 4, more preferably from 0 to 2. It should be understood that a material such as ST2S having a weight-average ethoxylation degree of about 2 may, for example, contain significant amounts of molecules that do not have ethoxylate, 1 mole of ethoxylate, 3 moles of ethoxylate, etc., and the distribution of ethoxylation may be wide, narrow or truncated, which still results in an overall weight-average ethoxylation degree of about 2. STS is particularly suitable for personal cleansing applications, and it has surprisingly and unexpectedly been found in the present invention that when polyvinyl alcohol having a relatively high weight-average molecular weight (e.g., from about 50,000 daltons to about 400,000 daltons, preferably from about 60,000 daltons to about 300,000 daltons, more preferably from about 70,000 daltons to about 200,000 daltons, and most preferably from about 80,000 daltons to about 150,000 daltons) is used as a film-forming agent and carrier, STS can be used as the primary surfactant, i.e., present in the solid sheet product in an amount greater than 50% by weight of the total surfactant content, without adversely affecting the film-forming properties and the stability of the overall composition. Correspondingly, in a specific embodiment of the present invention, STS is used as the primary surfactant in a solid sheet product. If present, the amount of STS in the solid sheet product of the present invention may be in the range of from about 10% to about 70%, preferably from about 20% to about 65%, more preferably from about 40% to about 60% by weight of the total weight of the solid sheet product.

[0123] Another class of anionic surfactants suitable for the practice of the present invention includes alkyl sulfates. These materials have the corresponding formula ROSO3M, where R is an alkyl or alkenyl group of from about 6 to about 20 carbon atoms, x is from 1 to 10, and M is a water-soluble cation such as ammonium, sodium, potassium, and triethanolamine. Preferably, R has from about 6 to about 18, preferably from about 8 to about 16, and more preferably from about 10 to about 14 carbon atoms. Previously, due to un-alkoxylated C6-C 20The compatibility of linear or branched alkyl sulfates (AS) with low molecular weight polyvinyl alcohols (e.g., those having a weight average molecular weight of no more than 50,000 daltons) in terms of film-forming properties and storage stability, so it is considered a preferred surfactant in soluble solid sheet products, especially as the main surfactant therein. However, the present invention has surprisingly and unexpectedly found that when polyvinyl alcohol having a relatively high weight average molecular weight (e.g., from about 50,000 daltons to about 400,000 daltons, preferably from about 60,000 daltons to about 300,000 daltons, more preferably from about 70,000 daltons to about 200,000 daltons, most preferably from about 80,000 daltons to about 150,000 daltons) is used as a film-forming agent and carrier, other surfactants such as LAS and / or STS can be used as the main surfactant in solid sheet products without adversely affecting the film-forming properties and the stability of the overall composition. Accordingly, in a particularly preferred embodiment of the present invention, it is desirable to provide solid sheet products having no more than about 20%, preferably from 0% to about 10%, more preferably from 0% to about 5%, most preferably from 0% to about 1% AS by weight of the solid sheet product.

[0124] Another class of anionic surfactants suitable for practicing the present invention includes C6-C 20 Linear or branched alkyl alkoxysulfates (AAS). In this class, particularly preferred are linear or branched alkyl ethoxysulfates (AES) having the corresponding formula RO(C2H4O) x SO3M, where R is an alkyl or alkenyl group of from about 6 to about 20 carbon atoms, x is from 1 to 10, and M is a water-soluble cation such as ammonium, sodium, potassium, and triethanolamine. Preferably, R has from about 6 to about 18, preferably from about 8 to about 16, more preferably from about 10 to about 14 carbon atoms. AES surfactants are generally prepared as condensation products of ethylene oxide and monohydric alcohols having from about 6 to about 20 carbon atoms. The alcohols available can be derived from fats, such as coconut oil or tallow, or can be synthetic. Lauryl alcohol and linear alcohols derived from coconut oil are preferred herein. Such alcohols are reacted with from about 1 to about 10, preferably from about 3 to about 5, and especially about 3 molar portions of ethylene oxide, and the resulting mixture of molecular species (e.g., having an average of 3 moles of ethylene oxide per mole of alcohol) is sulfated and neutralized. Highly preferred AES are those which are mixtures of individual compounds having an average alkyl chain length of from about 10 to about 16 carbon atoms and an average degree of ethoxylation of from about 1 to about 4 moles of ethylene oxide. When present, the amount of AAS in the solid sheet products of the present invention can range from about 2% to about 40%, preferably from about 5% to about 30%, more preferably from about 8% to about 12% by total weight of the solid sheet product.

[0125] Other suitable anionic surfactants include water-soluble salts of organic sulfuric acid reaction products having the general formula [R 1 -SO3-M], where R 1 is selected from the group consisting of: straight-chain or branched-chain saturated aliphatic hydrocarbon groups having from about 6 to about 20, preferably from about 10 to about 18 carbon atoms; and M is a cation. Preferred are the alkali metal salts and ammonium salts of sulfonated C 10-18 n-alkanes. Other suitable anionic surfactants include olefin sulfonates having from about 12 to about 24 carbon atoms. The α-olefins from which the olefin sulfonates are derived are monoolefins having from about 12 to about 24 carbon atoms, preferably from about 14 to about 16 carbon atoms. Preferably, they are straight-chain olefins.

[0126] Another class of anionic surfactants suitable for use in fabric and home care compositions are β-alkoxyalkane sulfonates. These compounds have the formula:

[0127]

[0128] wherein R1 is a straight-chain alkyl group having from about 6 to about 20 carbon atoms, R2 is a lower alkyl group having from about 1 (preferably) to about 3 carbon atoms, and M is a water-soluble cation as described above.

[0129] Additional examples of suitable anionic surfactants are the reaction products of fatty acids esterified with hydroxyethanesulfonic acid and neutralized with sodium hydroxide, where the fatty acids are derived from, for example, coconut oil; the sodium or potassium salts of fatty acid amides of methyl aminoethanesulfonate, where the fatty acids are derived from, for example, coconut oil. Other suitable anionic surfactants are succinamates, examples of which include disodium N-octadecylsulfosuccinate; diammonium laurylsulfosuccinate; tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinate; dipentyl ester of sodium sulfosuccinate; dihexyl ester of sodium sulfosuccinate; and dioctyl ester of sodium sulfosuccinate.

[0130] The nonionic surfactants that can be included in the solid sheet products of the present invention can be any conventional nonionic surfactants, including but not limited to: alkyl alkoxylated alcohols, alkyl alkoxylated phenols, alkyl polysaccharides (especially alkyl glucosides and alkyl polyglucosides), polyhydroxy fatty acid amides, alkoxylated fatty acid esters, sucrose esters, sorbitan esters and alkoxylated derivatives of sorbitan esters, amine oxides, etc. Preferred nonionic surfactants are those having the formula R 1 (OC2H4) n OH, where R 1 is C8-C 18an alkyl group or an alkylphenyl group, and n is from about 1 to about 80. Particular preference is given to C8-C having a weight-average ethoxylation degree of from about 1 to about 20, preferably from about 5 to about 15, more preferably from about 7 to about 10 18 alkyl ethoxylated alcohols, such as those commercially available from Shell nonionic surfactants. Other non-limiting examples of nonionic surfactants that can be used herein include: C6-C 12 alkylphenol alkoxylates, where the alkoxylate units can be ethyleneoxy units, propyleneoxy units, or mixtures thereof; C 12 -C 18 alcohols and C6-C 12 condensates of alkylphenols with ethylene oxide / propylene oxide block polymers, such as those from BASF C 14 -C 22 mid-chain branched alcohols (BA); C 14 -C 22 mid-chain branched alkyl alkoxylates, BAE x where x is from 1 to 30; alkyl polysaccharides, specifically alkyl polyglycosides; polyhydroxy fatty acid amides; and ether-capped poly(alkoxylated) alcohol surfactants. Suitable nonionic surfactants also include those sold by BASF under the trade name Those.

[0131] In a preferred embodiment, the nonionic surfactant is selected from sorbitan esters and alkoxylated derivatives of sorbitan esters, including sorbitan monolaurate sorbitan monopalmitate sorbitan monostearate sorbitan tristearate sorbitan monooleate sorbitan trioleate sorbitan isostearate, polyoxyethylene (20) sorbitan monolaurate polyoxyethylene (20) sorbitan monopalmitate polyoxyethylene (20) sorbitan monostearate polyoxyethylene (20) sorbitan monooleate polyoxyethylene (4) sorbitan monolaurate polyoxyethylene (4) sorbitan monostearate polyoxyethylene (5) sorbitan monooleate and combinations thereof.

[0132] The most preferred nonionic surfactants for the practice of the present invention include C6-C having a weight-average degree of alkoxylation in the range of 5 to 15 20 linear or branched alkyl alkoxylated alcohols (AA), more preferably C having a weight-average degree of alkoxylation in the range of 7 to 9 12 -C 14 linear ethoxylated alcohols. When present, the amount of AA-type nonionic surfactant in the solid sheet product of the present invention can be in the range of about 2% to about 40%, preferably about 5% to about 30%, more preferably about 8% to about 12% based on the total weight of the solid sheet product.

[0133] Amphoteric surfactants suitable for use in the solid sheet products of the present invention include those widely described as derivatives of aliphatic secondary and tertiary amines, wherein the aliphatic group can be linear or branched, and wherein one aliphatic substituent contains from about 8 to about 18 carbon atoms, and one aliphatic substituent contains an anionic water-soluble group such as carboxyl, sulfonate, sulfate, phosphate or phosphonate. Examples of compounds falling within this definition are sodium 3-dodecyl-aminopropionate, sodium 3-dodecylaminopropanesulfonate, sodium lauroyl sarcosinate, N-alkyl taurines (such as that prepared by the reaction of dodecylamine with sodium hydroxyethylsulfonate) and N-higher alkyl aspartic acids.

[0134] One class of amphoteric surfactants particularly suitable for introduction into solid sheet products for personal care applications (e.g., shampoos, facial or body cleansers, etc.) includes alkyl amphoacetates such as lauroyl amphoacetate and cocoamphoacetate. Alkyl amphoacetates can consist of monoacetates and diacetates. In some types of alkyl amphoacetates, the diacetate is an impurity or an unintended reaction product. When present, the amount of alkyl amphoacetate in the solid sheet product of the present invention can be in the range of about 2% to about 40%, preferably about 5% to about 30%, more preferably about 10% to about 20% based on the total weight of the solid sheet product.

[0135] Suitable zwitterionic surfactants include those widely described as derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds, wherein the aliphatic group can be linear or branched, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms, and one aliphatic substituent contains an anionic group such as carboxyl, sulfonate, sulfate, phosphate or phosphonate. Such suitable zwitterionic surfactants can be represented by the following formula:

[0136]

[0137] wherein R 2An alkyl, alkenyl or hydroxyalkyl group containing from about 8 to about 18 carbon atoms, from 0 to about 10 ethylene oxide moieties, and from 0 to about 1 glycerol moiety; Y is selected from nitrogen, phosphorus and sulfur atoms; R 3 is an alkyl or mono-hydroxyalkyl group containing from about 1 to about 3 carbon atoms; when Y is a sulfur atom, X is 1, and when Y is a nitrogen or phosphorus atom, X is 2; R 4 is an alkylene or hydroxyalkylene of from about 1 to about 4 carbon atoms, and Z is a group selected from: carboxylate, sulfonate, sulfate, phosphonate and phosphate groups.

[0138] Other zwitterionic surfactants suitable for use herein include betaines, which include higher alkyl betaines such as coco dimethyl carboxymethyl betaine, cocoamidopropyl betaine, coco betaine, lauramidopropyl betaine, oleyl betaine, lauryl dimethyl carboxymethyl betaine, lauryl dimethyl α-carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2-hydroxyethyl) carboxymethyl betaine, stearyl bis-(2-hydroxypropyl) carboxymethyl betaine, oleyl dimethyl γ-carboxypropyl betaine, and lauryl bis-(2-hydroxypropyl) α-carboxyethyl betaine. Sulfobetaines may be represented by: coco dimethyl sulfopropyl betaine, stearyl dimethyl sulfopropyl betaine, lauryl dimethyl sulfoethyl betaine, lauryl bis-(2-hydroxyethyl) sulfopropyl betaine, etc.; amido betaines and amido sulfobetaines, in which the RCONH(CH2)3 group (where R is C 11 -C 17 alkyl) is attached to the nitrogen atom of the betaine and may also be used in the present invention.

[0139] Cationic surfactants may also be used in the present invention, especially in fabric softener and hair conditioning products. When used in the preparation of products containing a cationic surfactant (as the main surfactant), it is preferred that such cationic surfactant be present in an amount of from about 2% to about 30%, preferably from about 3% to about 20%, more preferably from about 5% to about 15% by weight of the total weight of the solid sheet product.

[0140] Cationic surfactants may include DEQA compounds, which include descriptions of diamido active substances and active substances having mixed amide and ester linkages. Preferred DEQA compounds are generally prepared by the reaction of alkanolamines such as MDEA (methyldiethanolamine) and TEA (triethanolamine) with fatty acids. Some substances generally produced by such reactions include N,N-bis(acyloxyethyl)-N,N-dimethylammonium chloride, or N,N-bis(acyloxyethyl)-N,N-methylethylhydroxyethyl methyl sulfate ammonium, where the acyl groups are derived from animal fats, unsaturated and polyunsaturated fatty acids.

[0141] Other suitable active substances for use as cationic surfactants include reaction products of fatty acids with di-alkylenetriamines in a molar ratio of, for example, about 2:1, said reaction products comprising compounds of the formula:

[0142] R 1 -C(O)-NH-R 2 -NH-R 3 -NH-C(O)-R 1

[0143] wherein R 1 、R 2 are as defined above, and each R 3 is a C 1-6 alkylene group, preferably a diethylene group. Examples of these active substances are the reaction products of tallow fatty acid, rapeseed fatty acid or oleic acid with diethylenetriamine in a molar ratio of about 2:1, said reaction product mixtures comprising N,N"-ditallowoyl diethylenetriamine, N,N"-dirapeseed oil acyl diethylenetriamine or N,N"-dioleoyl diethylenetriamine of the formula:

[0144] R 1 -C(O)-NH-CH2CH2-NH-CH2CH2-NH-C(O)-R 1

[0145] wherein R 2 and R 3 are divalent ethylene groups, R 1 is as defined above, and when R 1 is an oleoyl group in commercially available oleic acid derived from plant or animal sources, acceptable examples of this structure include 223LL or 7021 available from Henkel Corporation.

[0146] Another active substance that can be used as a cationic surfactant has the following formula:

[0147] [R 1 -C(O)-NR-R 2 -N(R)2-R 3 -NR-C(O)-R 1 +X-

[0148] wherein R, R 1 、R 2 、R 3 and X - are as defined above. An example of this active substance is a softener based on di-fatty amidoamine of the formula:

[0149] [R1 -C(O)-NH-CH2CH2-N(CH3)(CH2CH2OH)-CH2CH2-NH-C(O)-R 1 + CH3SO4 - wherein R 1 -C(O) is an oleoyl group, a soft tallow group, or a hardened tallow group obtained commercially from Degussa under the trade names 222LT, 222, and 110, respectively.

[0150] A second class of DEQA ("DEQA(2)") suitable for use as an active substance as a cationic surfactant has the general formula:

[0151] [R3N + CH2CH(YR 1 )(CH2YR 1 )]X -

[0152] wherein each Y, R, R 1 and X - has the same meaning as above. An example of a preferred DEQA(2) is the "propyl" ester quaternary fabric softening agent active substance having the formula 1,2-bis(acyloxy)-3-trimethylpropylammonium chloride.

[0153] Suitable polymeric surfactants for use in the personal care compositions of the present invention include, but are not limited to, block copolymers of ethylene oxide and fatty alkyl residues, block copolymers of ethylene oxide and propylene oxide, hydrophobically modified polyacrylates, hydrophobically modified celluloses, siloxane polyethers, siloxane copolyol esters, polydimethylsiloxane bisquaternary salts, and co-modified amino / polyether siloxanes.

[0154] 3. Plasticizer

[0155] In a preferred embodiment of the present invention, the flexible porous soluble solid sheet article of the present invention further comprises a plasticizer in an amount preferably in the range of from about 0.1% to about 25%, preferably from about 0.5% to about 20%, more preferably from about 1% to about 15%, and most preferably from 2% to 12% by weight of the total weight of the solid sheet article. Correspondingly, the wet premix for forming such solid sheet articles may comprise from about 0.02% to about 20% by weight of the wet premix, in one embodiment from about 0.1% to about 10% by weight of the wet premix, and in one embodiment from about 0.5% to about 5% by weight of the wet premix of the plasticizer.

[0156] ​Suitable plasticizers for use in the present invention include, for example, polyols, copolyols, polycarboxylic acids, polyesters, polydimethylsiloxane copolyols, and the like.

[0157] Examples of available polyols include, but are not limited to: glycerol, diglycerol, ethylene glycol, polyethylene glycol (especially 200 to 600), propylene glycol, butylene glycol, pentylene glycol, glycerol derivatives (such as propoxylated glycerol), glycidol, cyclohexanedimethanol, hexanediol, 2,2,4-trimethylpentane-1,3-diol, pentaerythritol, urea, sugar alcohols (such as sorbitol, mannitol, lactitol, xylitol, maltitol, and other monohydric and polyhydric alcohols), monosaccharides, disaccharides, and oligosaccharides (such as fructose, glucose, sucrose, maltose, lactose, high fructose corn syrup solids, and dextrin), ascorbic acid, sorbate, ethylenediamine, amino acids, and the like.

[0158] Examples of polycarboxylic acids include, but are not limited to: citric acid, maleic acid, succinic acid, polyacrylic acid, and polymaleic acid.

[0159] Examples of suitable polyesters include, but are not limited to: glyceryl triacetate, acetylated monoglycerol, diethyl phthalate, triethyl citrate, tributyl citrate, acetyltriethyl citrate, and acetyltributyl citrate.

[0160] Examples of suitable polydimethylsiloxane copolyols include, but are not limited to: PEG-12 polydimethylsiloxane, PEG / PPG-18 / 18 polydimethylsiloxane, and PPG-12 polydimethylsiloxane.

[0161] Other suitable plasticizers include, but are not limited to: alkyl phthalates and allyl phthalates; naphthalene esters; lactates (e.g., sodium, ammonium, and potassium salts); sorbitol polyether-30; urea; lactic acid; sodium pyrrolidone carboxylate (PCA); sodium hyaluronate or hyaluronic acid; soluble collagen; modified proteins; monosodium L-glutamate; α and β-hydroxy acids, such as glycolic acid, lactic acid, citric acid, maleic acid, and salicylic acid; polyglyceryl methacrylate; polymeric plasticizers, such as polyquaternium; proteins and amino acids, such as glutamic acid, aspartic acid, and lysine; hydrogenated starch hydrolysates; other low molecular weight esters (e.g., esters of C2-C 10 alcohols and acids); and any other water-soluble plasticizers known to those skilled in the food and plastics industries; and mixtures thereof.

[0162] Particularly preferred examples of plasticizers include glycerol, ethylene glycol, polyethylene glycol, propylene glycol, and mixtures thereof. The most preferred plasticizer is glycerol.

[0163] 4. Additional ingredients

[0164] In addition to the above components such as water-soluble polymers, surfactants, and plasticizers, the solid sheet products of the present invention may contain one or more additional components according to their intended applications. Such one or more additional components may be selected from the group consisting of: fabric care active substances, dishwashing active substances, hard surface cleaning active substances, beauty and / or skin care active substances, personal cleaning active substances, hair care active substances, oral care active substances, feminine care active substances, baby care active substances, and any combination thereof.

[0165] Suitable fabric care active substances include, but are not limited to: organic solvents (linear or branched lower C1-C8 alcohols, diols, glycerol or ethylene glycol; lower amine solvents such as C1-C4 alkanolamines, and mixtures thereof; more specifically 1,2-propanediol, ethanol, glycerol, monoethanolamine and triethanolamine), carriers, hydrotropes, builders, chelating agents, dispersants, enzymes and enzyme stabilizers, catalytic materials, bleaches (including photo-bleaches) and bleach activators, fragrances (including encapsulated fragrances or fragrance microcapsules), colorants (such as pigments and dyes, including toner dyes), optical brighteners, dye transfer inhibitors, clay soil removal / anti-redeposition agents, structurants, rheology modifiers, foam suppressants, processing aids, fabric softeners, antimicrobial agents, etc.

[0166] Suitable hair care active substances include, but are not limited to: Class II moisture control materials for reducing curl (salicylic acid and derivatives, organic alcohols and esters), cationic surfactants (especially the water-insoluble type having a solubility preferably less than 0.5 g / 100 g of water, more preferably less than 0.3 g / 100 g of water in water at 25 °C), high melting point aliphatic compounds (e.g., fatty alcohols, fatty acids, and mixtures thereof having a melting point of 25 °C or higher, preferably 40 °C or higher, more preferably 45 °C or higher, still more preferably 50 °C or higher), silicone compounds, conditioners (such as hydrolyzed collagen sold under the trade name Peptein 2000 by Hormel, vitamin E sold under the trade name Emix-d by Eisai, panthenol from Roche, panthenol-based ethyl ether from Roche, hydrolyzed keratin, proteins, plant extracts and nutrients), preservatives (such as benzyl alcohol, methyl paraben, propyl paraben and imidazolidinyl urea), pH regulators (such as citric acid, sodium citrate, succinic acid, phosphoric acid, sodium hydroxide, sodium carbonate), salts (such as potassium acetate and sodium chloride), colorants, fragrances or aromatics, polyvalent chelating agents (such as disodium ethylenediaminetetraacetate), UV and infrared shielding and absorbing agents (such as octyl salicylate), hair bleaches, hair perming agents, hair setting agents, anti-dandruff agents, antimicrobial agents, hair growth or restoration agents, co-solvents or other additional solvents, etc.

[0167] Suitable cosmetic and / or skin care active substances include those recognized for use in cosmetics and described in reference books such as the "CTFA Cosmetic Ingredient Handbook", 2nd Edition (The Cosmetic, Toiletries, and Fragrance Association, Inc. 1988, 1992). Additional non-limiting examples of suitable cosmetic and / or skin care active substances include preservatives, fragrances or odorants, colorants or dyes, thickeners, humectants, emollients, pharmaceutically active substances, vitamins or nutrients, sunscreens, deodorants, sensates, plant extracts, nutrients, astringents, cosmetic particles, absorbent particles, fibers, anti-inflammatory agents, skin lightening agents, skin color correctors (which act to improve the overall skin tone and may contain vitamin B3 compounds, glycosamines, hexamidine compounds, salicylic acid, 1,3-dihydroxy-4-alkylbenzenes such as hexylresorcinol and retinoids), skin tanning agents, exfoliants, humectants, enzymes, antioxidants, free radical scavengers, anti-wrinkle active substances, anti-acne agents, acids, bases, minerals, suspending agents, pH adjusters, pigment particles, anti-microbial agents, insect repellents, shaving lotions, co-solvents or other additional solvents, etc.

[0168] The solid sheet article of the present invention may also contain other optional ingredients known for or otherwise useful in compositions, provided that such optional substances are compatible with the selected base substances described herein or do not otherwise unduly impair product performance.

[0169] Non-limiting examples of product type embodiments that can be formed from the solid sheet article of the present invention include laundry detergent products, fabric softening products, hand wash products, shampoos or other hair treatment products, body cleansing products, shaving preparation products, dish cleaning products, personal care bases containing drugs or other skin care active substances, moisturizing products, sunscreen products, cosmetic or skin care products, deodorant products, oral care products, feminine cleansing products, baby care products, products containing fragrances, etc.

[0170] Test 1: Scanning electron microscopy (SEM) method for determining the average surface pore size of sheet articles

[0171] SEM micrographs of the samples were obtained using a Hitachi TM3000 tabletop microscope (S / N: 123104 - 04). The sample area of the solid sheet article of the present invention was approximately 1 cm × 1 cm and was cut from a larger sheet. Images were collected at a magnification of 50x and the unit was operated at 15 kV. A minimum of 5 micrograph images were collected from randomly selected locations on each sample, resulting in a total analysis area of approximately 43.0 mm 2 and the average pore size on each sample was estimated.

[0172] Then, the SEM micrographs are first processed using the image analysis toolbox in Matlab. If needed, the images are converted to grayscale. For a given image, the 'imhist' Matlab function is used to generate a histogram of the intensity values of each individual pixel. Typically, from such histograms, two distinct distributions are evident, corresponding to the pixels of the brighter sheet surface and the darker regions within the pores. A threshold is selected, corresponding to the intensity value between the peaks of these two distributions. Then, all pixels having intensity values below this threshold are set to an intensity value of 0, while pixels having higher intensity values are set to 1, thus producing a binary black-and-white image. The binary image is then analyzed using ImageJ (https: / / imagej.nih.gov, version 1.52a) to examine both the pore area fraction and the pore size distribution. The scale bar of each image is used to provide the pixel / mm scale factor. For the analysis, the auto-thresholding and analyze particles functions are used to isolate each pore. The output of the analysis function includes the area fraction of the overall image as well as the pore area and pore perimeter of each individual pore detected.

[0173] The average pore diameter is defined as D A 50: 50% of the total pore area is composed of pores having a hydraulic diameter equal to or smaller than the D A 50 average diameter.

[0174] Hydraulic diameter = '4 * pore area (m 2 ) / pore perimeter (m)'.

[0175] It is an equivalent diameter, and not all of the calculated pores are circular.

[0176] Test 2: Micro-computed tomography (μCT) method for determining the overall or regional average pore size and average pore wall thickness of open-cell foams (OCF) (μCT) method

[0177] Porosity is the ratio between the void space and the total space occupied by the OCF. The porosity can be calculated from μCT scans by segmenting the void space via a threshold and determining the ratio of void voxels to total voxels. Similarly, the solid volume fraction (SVF) is the ratio between the solid space and the total space, and the SVF can be calculated as the ratio of the occupied voxels to the total voxels. Both porosity and SVF are average scalar values, which do not provide structural information such as the pore size distribution in the height direction of the OCF or the average pore wall thickness of the OCF struts.

[0178] To characterize the 3D structure of the OCF, a μCT scanner capable of acquiring datasets with high isotropic spatial resolution was used to image the samples. Here is a GE phoenix v|tome|x m with the following settings: 240 kV microfocus tube, 180 kV and 120 μA, 500 projection images; 500 μs and 5 averages, voxel size less than 10 microns per pixel. After scanning, the projection images were reconstructed into 3D images and converted into an 8-bit format stack of two-dimensional images in the height direction (or Z direction) for analysis.

[0179] The stack of these images was used to estimate the variation of the sphere diameter between slices with the depth of the OCF. First, the walls and pores were distinguished via thresholding, and then the "Local Thickness" script (see Robert Dougherty and Karl-Heinz Kunzelmann, Microscopy&Microanalysis, August 2007, 13(S02)) was run in ImageJ to obtain the pore diameter.

[0180] To obtain samples for measurement, a single layer was flattened and sliced. During sampling, folding, wrinkling, and tearing were avoided. Also, the possibility of distortion and compression was minimized. A ring holder was used to support the cut samples so that direct pressure on their upper and lower surfaces could be avoided.

[0181] The "Local Thickness" script gave the calculated results of the sphere diameter from slice to slice. For the overall average pore diameter (μm), it is the average of all pore diameters. For the top average pore diameter (μm), middle average pore diameter (μm), and bottom average pore diameter (μm), the image stack was divided into three equal parts from top to bottom, and then the average of each part was calculated.

[0182] Test 3: Percentage of open-cell content of sheet articles

[0183] The percentage of open-cell content was measured via gas pycnometry. Gas pycnometry is a common analytical technique for accurately determining volume using the gas displacement method. An inert gas such as helium or nitrogen was used as the displacement medium. A sample of the solid sheet product of the present invention was sealed in an instrument compartment of known volume, an appropriate inert gas was introduced, and then expanded to another precise internal volume. The pressures before and after expansion were measured and used to calculate the volume of the sample product.

[0184] ASTM standard test method D2856 uses an older air pycnometer model and provides a procedure for determining the percentage of open cells. This device is no longer manufactured. However, the percentage of open cells can be determined conveniently and accurately by performing tests using a Micromeritics AccuPyc pycnometer. ASTM procedure D2856 describes five methods (A, B, C, D, and E) for determining the percentage of open cells in foam materials. For these experiments, nitrogen gas and ASTM foampyc software can be used with an Accupyc 1340 to analyze the samples. Method C in the ASTM procedure is used to calculate the percentage of open cells. This method simply compares the geometric volume measured, for example, using thickness and standard volume, with the open cell volume measured by the Accupyc, according to the following equation:

[0185] Percentage of open cells = Open cell volume of the sample / Geometric volume of the sample * 100

[0186] These measurements are recommended to be performed by Micromeretics Analytical Services, Inc. (One Micromeritics Dr, Suite 200, Norcross, GA 30093). More information related to this technology can be found on the Micromeretics Analytical Services website (www.particletesting.com or www.micromeritics.com), or published in "Analytical Methods in Fine particle Technology" by Clyde Orr and Paul Webb.

[0187] Test 4: Final water content of sheet articles

[0188] The final water content of the solid sheet products of the present invention was obtained by using a Mettler Toledo HX204 moisture analyzer (S / N B706673091). At least 1 g of the dried sheet product was placed on the measurement tray. Then the standard procedure was performed, with the additional procedure settings being a 10-minute analysis time and a temperature of 110 °C.

[0189] Test 5: Thickness of sheet articles

[0190] The thickness of the flexible, porous, soluble solid sheet product of the present invention is obtained by using a micrometer or thickness gauge, such as the bench-type digital micrometer, Mitutoyo Corporation model IDS-1012E (Mitutoyo Corporation, 965 Corporate Blvd, Aurora, IL, USA 60504). The micrometer has a platen with a 1-inch diameter and weighs approximately 32 grams, and measures the thickness under a pressure of approximately 0.09 psi (6.32 gm / cm 2 ) applied.

[0191] The thickness of the flexible, porous, soluble solid sheet product is measured by raising the platen, placing a portion of the sheet product on the base under the platen, carefully lowering the platen to contact the sheet product, releasing the platen, and measuring the thickness of the sheet product in millimeters according to the digital readout. The sheet product should extend completely to the entire edge of the platen to ensure measurement of the thickness under the lowest possible surface pressure, unless in the case of a non-flat, more rigid substrate.

[0192] Test 6: Basis weight of sheet articles

[0193] The basis weight of the flexible, porous, soluble solid sheet product of the present invention is calculated as the weight per unit area of the sheet product (grams / m 2 ). The area is calculated as the area projected onto a flat surface perpendicular to the outer edge of the sheet product. The solid sheet product of the present invention is cut into 10 cm x 10 cm sample squares, so the area is known. Each such sample square is then weighed, and the resulting weight is then divided by the known area of 100 cm 2 to determine the corresponding basis weight.

[0194] For an article of irregular shape, if it is a flat object, the area is calculated based on the area enclosed within the outer perimeter of such object. Thus, for a spherical object, the area is calculated according to the average diameter as 3.14 x (diameter / 2) 2 . Thus, for a cylindrical object, the area is calculated according to the average diameter and average length as diameter x length. For an irregular-shaped three-dimensional object, the area is calculated based on the side projected onto a flat surface perpendicular to the side with the largest external dimension. This can be achieved by carefully tracing the external dimensions of the object onto a piece of paper with a pencil, then by roughly counting the number of squares and multiplying by the known area of the square, or by taking a photograph of the traced area including a scale (shaded for contrast) and using image analysis techniques to calculate the area.

[0195] Test 7: Density of sheet articles

[0196] The density of the flexible porous soluble solid sheet product of the present invention is determined by the following formula: Calculated density = basis weight of the porous solid / (porous solid thickness x 1,000). The basis weight and thickness of the soluble porous solid are determined according to the methods described above.

[0197] Test 8: Specific surface area of sheet articles

[0198] The specific surface area of the flexible porous soluble solid sheet product is measured via gas adsorption techniques. The surface area is a measure of the exposed surface of the solid sample at the molecular level. The BET (Brunauer, Emmet, and Teller) theory is the most popular model used to determine the surface area and it is based on the gas adsorption isotherm. Gas adsorption uses physical adsorption and capillary condensation to measure the gas adsorption isotherm. This technique is outlined by the following steps; the sample is placed in a sample tube and heated under vacuum or flowing gas to remove contaminants on the sample surface. The sample weight is obtained by subtracting the weight of the empty sample tube from the total weight of the degassed sample and sample tube. The sample tube is then placed in the analysis port and analysis is started. The first step in the analysis method is to evacuate the sample tube and then use helium gas to measure the free space volume of the sample tube at liquid nitrogen temperature. The sample tube is then evacuated a second time to remove the helium. The instrument then starts collecting the adsorption isotherm by quantitatively introducing krypton gas at user-specified intervals until the desired pressure measurement is achieved. The sample can then be analyzed using ASAP 2420 and krypton gas adsorption. These measurements are recommended to be performed by Micromeretics Analytical Services, Inc. (One Micromeritics Dr, Suite 200, Norcross, GA 30093). More information related to this technique can be found on the Micromeretics Analytical Services website (www.particletesting.com or www.micromeritics.com), or published in the book “Analytical Methods in Fine Particle Technology” by Clyde Orr and Paul Webb.

[0199] Test 9: Dissolution rate

[0200] First, the solid sheet is stored at an ambient relative humidity of 50 ± 2% and an ambient temperature of 23 ± 1 °C for 24 hours (i.e., the conditioning step). After the above initial conditioning step, discs with a diameter of 25 mm are first cut from the large solid sheet using a 25 mm hollow punch. The required number of foam discs is set such that the total mass of all foam discs is not less than 0.1 g.

[0201] Then stack the required number of foam discs in an end-to-end orientation and place them in an Omnifit TM EZ chromatographic column (006EZ-25-10-AF) with an inner diameter of 25 mm, a length of 100 m, and an adjustable removable end piece. The stack of foam discs is placed inside the column such that the flow direction through the column is perpendicular to the top surface of the foam discs. Once placed inside the column, the end piece is inserted into the column and adjusted until the vertical distance between the two inner frits is equal to the thickness of the stack of foam discs.

[0202] Masterflex silicone tubing (MFLEX SILICONE#25 25') and a Masterflex peristaltic pump (MFLX L / S1CH300R 115 / 230 13124) are used to control the water flow through the column. The system flow rate is calibrated by passing water through the pump, tubing, and empty column at different pump RPM settings and recording the amount of water collected over a defined time period. A flow rate of 5 liters per hour is used for all experiments.

[0203] Both the inlet and outlet tubing are placed in a 1-liter beaker containing 500 ml of deionized water at ambient temperature. The beaker is placed on a magnetic stirrer plate, and a magnetic stir bar with a length of 23 mm and a thickness of 10 mm is placed in the beaker, and the stirrer rotation speed is set to 300 rpm. A Mettler Toledo S230 conductivity meter is calibrated to 1413 μS / cm, and the probe is placed in the water in the beaker.

[0204] Water is started to flow through the system. Once the first drop of water is visible inside the column and contacts the foam, the data recording function of the conductivity meter is started. Data is recorded for at least 20 minutes.

[0205] To estimate the time required for the foam to reach a 90% or 95% dissolution percentage, a calibration curve is first generated where multiple layers of foam discs are dropped one by one into a stirred beaker of 500 ml of deionized water. The mass of each individual foam disc and the conductivity after 5 minutes are recorded. This process is repeated for up to a total of 5 discs. A linear function is fit to the data and then used to estimate the maximum conductivity in each dissolution experiment based on the total mass of the foam discs placed in the column. The dissolution percentage is calculated as follows: Dissolution % = Conductivity measured in experiment / Maximum conductivity * 100

[0206] The time required to reach a 90% or 95% dissolution percentage can be found from this calculated data. The calibration procedure is repeated for each test formulation.

[0207] Test 10: Bubble size

[0208] The bubble size of the aerated premix is measured as follows:

[0209] First, a rectangular glass coverslip with a width and length of 2 cm and a thickness of 1 mm is glued to a glass slide with a width of 6 cm and a length of 2 cm, such that a cavity with a thickness of 1 mm, a length of 2 cm, and a width slightly less than 2 cm is located at the center of the glass slide. The width of the cavity must be kept less than 2 cm so that an additional coverslip can be placed on top of the cavity.

[0210] To capture images for bubble size analysis, an inflated liquid foam is deposited into the cavity using a spatula, and another coverslip is placed on top and gently pressed down to reduce the thickness of the liquid to 1 mm.

[0211] Images are captured using a SMZ-T4 Chongqing Optec microscope and an RZIMAGE MicroUL300 digital camera. The glass slide is placed on the backlight area of the microscope, and the magnification is adjusted such that the image area is not less than 16 mm 2 . An additional image is taken with a transparent ruler placed within the image area such that the scale lines can be seen and used to determine the pixel-to-distance ratio.

[0212] The “imfindcircles” function in the Image Analysis Toolbox of Matlab 2017b software is used to calculate the bubble size. For each image, the function is called four times with pixel size ranges of 21 to 40, 41 to 50, 51 to 100, and 101 to 200, where 20 pixels correspond to a length of approximately 60 microns. The sensitivity parameter is set to 0.95. The bubble radii estimated by each call of the function are combined to generate a single distribution, and the radii are converted to microns using the calibration image generated with the transparent ruler.

[0213] Examples

[0214] The following examples further describe and illustrate embodiments within the scope of the present invention. These examples are given for illustrative purposes only and should not be construed as limiting the present invention, as many variations are possible without departing from the essence and scope of the present invention. Unless otherwise specified, all amounts in the examples are concentrations by weight of the total composition, i.e., wt / wt percentages.

[0215] Example 1: Improved pore structure of solid sheet articles in the stepwise belt drying method

[0216] A wet premix (i.e., slurry) containing the components of the solid sheet product (Formulation 1) shown in Table 1 below and additional water is prepared to produce a total solids content of approximately 32 wt% (i.e., the total water content in the slurry is approximately 68 wt%).

[0217] Table 1

[0218]

[0219] The slurry thus formed is then aerated and dried in a drum dryer or a belt dryer using the parameters shown below. In particular, the belt dryer used herein is shown in Figure 1 and includes three heating zones, where the temperatures in these heating zones are shown in Table 3 below.

[0220] Table 2

[0221]

[0222]

[0223] Table 3

[0224]

[0225] According to Tests 2, 5, and 6 as described herein, the parameters of the solid sheet products prepared by Processes 1 to 7 (including overall average pore diameter (OAPD), standard deviation of OAPD, bottom / middle / top average pore diameter, thickness, basis weight) were measured and are shown in Table 4 below. In addition, the average pore diameters at different heights (i.e., different thicknesses) on the entire solid sheet products prepared by Processes 1 to 7 are shown in Figure 3 .

[0226] Table 4

[0227]

[0228] Data (see Figure 3 and Table 4) show that, compared to the ordinary belt heating method (e.g., Processes 2 to 5), the stepwise belt drying method according to the present disclosure (i.e., Processes 6 and 7, where T b1 > T t1 ; T b1 > T b2 ; and T t1 < T t2 ) can achieve a significantly improved uniformity in the pore size distribution in the solid sheet. In particular, Figure 3The curves for Processes 6 and 7 (shown as triangles) are flat, similar to Process 1 (shown as a circle), while the curves for Processes 2 to 5 (shown as dashed lines) have distinct peaks, indicating that the pore size distribution in the articles prepared by Processes 6 and 7 is more uniform compared to the pore sizes in the articles prepared by Processes 2 to 5. Also, the stepwise belt drying method according to the present disclosure (i.e., Processes 6 and 7) can produce much thicker solid sheets (i.e., 1.9 mm or 1.8 mm vs. 1.0 mm) compared to the drum drying method. Also as shown in Table 4, the standard deviation of the overall average pore size in the solid sheets obtained by the stepwise belt heating method (Processes 6 and 7) is very close to the standard deviation of the overall average pore size obtained by the drum dryer (Process 1), i.e., 104 μm / 140 μm vs. 76 μm.

[0229] In addition, as an added benefit, the overall average pore size in the solid sheets obtained by the stepwise belt drying method according to the present disclosure is within a preferred range, which can provide a balance between the dissolution and leakage of the juice / paste contained in the multi-layer sheet article.

[0230] Example 2: Composition of articles for the stepwise belt drying method

[0231] The following are examples of articles prepared by the stepwise drying method according to the present disclosure as described in Example 1.

[0232] Table 5

[0233]

[0234]

[0235] The dimensions and values disclosed herein should not be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to represent the recited value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to represent "about 40 mm".

[0236] Unless expressly excluded or otherwise limited, each document cited herein, including any cross-referenced or related patent or patent application and any patent application or patent to which this application claims priority or its beneficial effects, is hereby incorporated by reference in its entirety. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone or in any combination with any one or more other references anticipates, suggests, or discloses any such invention. Further, when any meaning or definition of a term in this invention conflicts with the same term's meaning or definition in a document incorporated by reference, the meaning or definition assigned to the term in this invention shall govern.

[0237] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the present invention. Accordingly, it is intended to cover all such changes and modifications that fall within the scope of the present invention in the appended claims.

Claims

1. A continuous method for preparing a sheet product, the continuous method comprising the following steps: a) Prepare a wet premix containing a water-soluble polymer and a surfactant and having a viscosity of 1,000 cps to 25,000 cps as measured at 40 °C and 1 s -1 ; b) Inflating the wet premix to form an inflated wet premix having a density of from 0.05 g / ml to 0.5 g / ml; c) Shaping the inflated wet premix into a sheet having a top side and a bottom side; and d) Drying the shaped inflated wet premix sheet on a conveyor belt, wherein the bottom side of the formed sheet contacts the conveyor belt, wherein the conveyor belt is configured to sequentially pass through a plurality of heating zones having a heating temperature in the range of 70°C to 200°C; wherein the plurality of heating zones includes a first heating zone and a second heating zone, and the second heating zone is located downstream of the first heating zone; wherein the first heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a first top heating temperature (T t1 ) and a first bottom heating temperature (T b1 ) for a first heating duration of from 0.01 minute to 20 minutes; wherein the second heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a second top heating temperature (T t2 ) and a second bottom heating temperature (T b2 ) for a second heating duration of from 0.01 minute to 20 minutes; and where T b1 > T t1 ; T b1 > T b2 ; and T t1 < T t2 .

2. The method according to claim 1, wherein the first top heating temperature (T t1 ) is in the range of 70 °C to 160 °C; wherein the first bottom heating temperature (T b1 ) is in the range of 80 °C to 190 °C; wherein the second top heating temperature (T t2 ) is in the range of 100 °C to 200 °C; and wherein the second bottom heating temperature (T b2 ) is in the range of 70 °C to 170 °C.

3. The method according to claim 1 or 2, wherein T t1 is in the range of 80 °C to 150 °C, preferably 80 °C to 140 °C, more preferably 90 °C to 120 °C; wherein T b1 is in the range of 90 °C to 170 °C, preferably 100 °C to 160 °C, more preferably 110 °C to 140 °C; wherein T t2 is in the range of 110 °C to 190 °C, preferably 120 °C to 180 °C, more preferably 130 °C to 160 °C; and wherein T b2 is in the range of 70 °C to 150 °C, preferably 70 °C to 120 °C, more preferably 70 °C to 110 °C; and where T b2 ≤ T t2 .

4. The method according to any one of claims 1 to 3, wherein the plurality of heating zones further includes a third heating zone, and wherein the conveyor belt is configured to pass through the third heating zone; wherein the third heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at a third top heating temperature (T t3 ) and a third bottom heating temperature (T b3 ) for a third heating duration of from 0.01 minute to 20 minutes; and When the third heating zone is located downstream of the second heating zone, T b2 ≥ T b3 ; T t2 ≤T t3 ; and T b3 ≤T t3 , Wherein when the third heating zone is located downstream of the first heating zone and upstream of the second heating zone, T b1 ≥T b3 ≥T b2 ; T t1 ≤T t3 ≤T t2 and When the third heating zone is located upstream of the first heating zone, T b3 ≥T b1 ; T t3 ≤T t1 ; and T b3 ≥T t3 , Preferably, where T t3 is in the range of 90 °C to 200 °C; and where T b3 is in the range of 70 °C to 180 °C.

5. The method according to any one of claims 1 to 4, wherein the plurality of heating zones in total comprises 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or more heating zones, wherein the nth heating zone is configured to simultaneously heat the top side and the bottom side of the formed sheet at the nth top heating temperature (T tn ) and the nth bottom heating temperature (T bn ), and wherein T bn ≥T b(n+1) ; and T tn ≤T t(n+1) ; Preferably, wherein the plurality of heating zones includes from 0.1 to 5 heating zones per meter of the conveyor belt.

6. The method according to any one of the preceding claims, wherein the first heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or wherein the second heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or wherein the third heating duration is from 0.05 minutes to 10 minutes, preferably from 0.1 minutes to 8 minutes; and / or wherein the total heating duration in the plurality of heating zones is from 0.05 minutes to 30 minutes, preferably from 0.1 minutes to 20 minutes, more preferably from 0.15 minutes to 15 minutes.

7. The method according to any one of the preceding claims, wherein the shaped inflated wet premix sheet is characterized in that the thickness is in the range of from 0.5 mm to 20 mm, preferably from 0.8 mm to 15 mm, more preferably from 1 mm to 10 mm, still more preferably from 1.2 mm to 8 mm, most preferably from 1.4 mm to 6 mm, for example 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm or any range therebetween.

8. The method according to any one of the preceding claims, wherein the wet premix comprises from 3% to 70%, preferably from 4% to 50%, more preferably from 5% to 40% of the water-soluble polymer based on the total weight of the wet premix; and / or wherein the wet premix comprises from 1% to 40%, preferably from 2% to 35%, more preferably from 5% to 30% of the surfactant based on the total weight of the wet premix; and / or wherein the density of the inflated wet premix is in the range of from 0.08 g / ml to 0.4 g / ml, preferably from 0.1 g / ml to 0.35 g / ml; and / or wherein the wet premix is characterized in that the solids content is in the range of from 15% to 70%, preferably from 20% to 50%, more preferably from 25% to 45% by weight of the wet premix; and / or wherein the wet premix is characterized in that the viscosity, as measured at 40 °C and 1 s -1 is in the range of 3,000 cps to 24,000 cps, preferably 5,000 cps to 23,000 cps, more preferably 10,000 cps to 20,000 cps.

9. The method according to any one of the preceding claims, wherein the plurality of heating zones are configured to heat the top side of the formed sheet by convective heating and the bottom side of the formed sheet by conductive heating.

10. A flexible porous soluble solid sheet product, the flexible porous soluble solid sheet product comprising a water-soluble polymer and a surfactant, wherein the solid sheet product is characterized in that: (i) the thickness is in the range of 1.5 mm to 20 mm; and (ii) the percentage of open-cell content is 80% to 99.9%; (iii) the overall average pore size is 100 μm to 1000 μm; and (iv) the standard deviation of the overall average pore size is 10 μm to 250 μm; wherein the solid sheet product has opposite top and bottom surfaces, the top surface having a surface average pore size greater than 100 μm; wherein the solid sheet product includes a top region adjacent to the top surface, a bottom region adjacent to the bottom surface, and an intermediate region between the top region and the bottom region; wherein the top region, the intermediate region, and the bottom region have the same thickness, and each of the top region, the intermediate region, and the bottom region is characterized by an average pore size; and wherein the ratio of the average pore size in the bottom region to the average pore size in the top region is 0.6 to 1.

5.

11. The flexible porous soluble solid sheet product according to claim 10, wherein the solid sheet product is prepared by the method according to any one of claims 1 to 9.

12. The flexible porous soluble solid sheet product according to claim 10 or 11, wherein the solid sheet product is characterized in that the thickness is 1.5 mm to 20 mm, preferably 1.5 mm to 15 mm, more preferably 1.5 mm to 10 mm, still more preferably 1.5 mm to 8 mm, most preferably 1.5 mm to 6 mm; and / or wherein the solid sheet product is characterized in that the percentage of open-cell content is 85% to 99.9%, preferably 90% to 99.9%; and / or wherein the overall average pore size is 20 μm to 600 μm, preferably 50 μm to 500 μm, more preferably 100 μm to 400 μm; and / or wherein the standard deviation of the overall average pore size is 20 μm to 250 μm, preferably 30 μm to 250 μm, more preferably 50 μm to 200 μm.

13. A belt drying system for preparing a sheet product, wherein the system comprises: a conveyor belt configured to convey a wet premix and form the wet premix into a sheet having a top side and a bottom side, a plurality of heating components configured to dry the wet premix by heating to form the sheet, and a heat source configured to supply heat to the plurality of heating components, wherein the conveyor belt is configured to sequentially pass through the plurality of heating members having a heating temperature in the range of 70°C to 200°C; wherein the plurality of heating members includes a first heating member and a second heating member, and the second heating member is located downstream of the first heating member; wherein the first heating member is configured to simultaneously heat the top side and the bottom side of the formed sheet at a first top heating temperature (T t1 ) and a first bottom heating temperature (T b1 ) for a first heating duration of from 0.01 minute to 20 minutes; wherein the second heating member is configured to simultaneously heat the top side and the bottom side of the formed sheet at a second top heating temperature (T t2 ) and a second bottom heating temperature (T b2 ) for a second heating duration of from 0.01 minute to 20 minutes; and where T b1 > T t1 ; T b1 > T b2 ; and T t1 < T t2 .

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