Highly concentrated dissolvable fabric softening tablets

Abstract

The present invention relates to a highly concentrated fabric softener formulation which is provided in the form of a water-soluble tablet and which can be conveniently used with detergents in domestic washing machines. The formulations include a combination of an anionic surfactant and a cationic and / or anionic polymer that act together on the fabric to produce a softening effect. The product form allows a highly concentrated product to be achieved such that it contains a high proportion of the active ingredient, thus substantially reducing both the occupied volume and mass while providing the same amount of active ingredient and compliant efficacy. The properties of the formulations of the present invention are equivalent to or superior to those of a standard liquid two-in-one detergent / fabric softener combination at the same dose.

Description

Field of the Invention

[0001] The present invention relates to the field of household laundry fabric softening and conditioning products. Disclosed herein is a highly concentrated fabric softening preparation which is provided in the form of a soluble solid tablet and can be conveniently used together with a detergent in a household washing machine. This product form allows for a highly concentrated product, enabling it to contain a high proportion of active ingredients, and thus greatly reducing the volume and mass occupied while providing the same amount of active ingredients and softening efficacy. The performance of the preparation of the present invention is equivalent to or superior to that of a standard liquid two-in-one detergent / fabric softener combination at the same dosage. BACKGROUND OF THE INVENTION

[0003] Fabric softening compositions for laundry are very common and generally take one of three forms. They can be in the form of a liquid preparation added to the final rinse cycle of the laundry load, or as a two-in-one detergent / softener liquid preparation added to the wash cycle, or as an insoluble tablet impregnated with a fabric softener and tumbled separately with the laundry in a dryer. Each of these forms of fabric softeners has drawbacks. Although liquid fabric softeners achieve more comprehensive fabric surface coverage and contact through the mixing and dispersion of the rinse water in the laundry load and the mechanical agitation of the laundry load, the main component in liquid fabric softeners is water. Therefore, for transportation, they are large and bulky and not convenient for storage. The two-in-one detergent / softener liquid preparation also has the inherent problem of large volume of liquid preparations. Insoluble tablets result in waste generation because the used tablets must be discarded after use. And they are easily wrapped by large fabrics such as sheets and towels during the drying process, resulting in their inability to fully contact all fabric surfaces in the load.

[0004] In recent years, detergents in the form of soluble tablets (including products provided by the present patent applicant) have been widely popularized. However, technical constraints limit the inability to provide fabric softeners in a similar tablet form. The traditional softening active ingredients used in fabric softeners have poor compatibility with the structuring agents required for manufacturing solid tablets. The term "structuring agent" is used herein to denote an ingredient that helps form a solid matrix and stably load the active ingredients therein. Examples of water-soluble structuring agents in soluble tablets for laundry include starch and polyvinyl alcohol, which provide volume and flexibility to the tablets.

[0005] The main challenge in providing fabric softeners in the form of soluble tablets is that traditional softening active substances are designed to have poor water solubility. The softening active substances must adhere to and disperse on the fabric surface to form a coating layer on the fabric fibers. If they have too high a solubility, they will not be able to effectively coat the fabric and will thus be ineffective as a softener.

[0006] Through their product formulation trials, the inventors have learned that the poor compatibility of traditional fabric softening active substances with water-soluble structuring agents in solid product forms means that these active substances tend to leach out of the dissolvable tablets. Over time, they no longer remain within the solid matrix and a greasy or waxy coating quickly forms on the tablet surface. The feel of this coating will be familiar to consumers using non-dissolvable fabric softening tablets, which are typically made of non-woven polypropylene and impregnated with fabric softening active substances for use with laundry in a dryer. For non-dissolvable tablets, this coating is less of a problem as the integrity of the non-woven tablets allows them to be stackable and consumers can easily separate them from one another. However, if the active ingredients migrate out, this coating can cause problems with stackable dissolvable tablets. When the dissolvable tablets stick together, they are more fragile and prone to tearing.

[0007] Although fabric softening active ingredients are generally poorly soluble, if dissolvable fabric softening tablets are to be provided, these active substances must be mixed with the water-soluble structuring agents used and remain fixed in solid form.

[0008] It would be beneficial to provide dissolvable tablets that overcome the above challenges, are easily soluble in water, and are capable of providing at least an equivalent softening efficacy to some conventional forms of fabric softeners. SUMMARY OF THE INVENTION

[0009] Dissolvable fabric softening tablets have been invented that are easily soluble during the wash cycle of a domestic washing machine but remain stable for long periods under room temperature storage conditions. The dissolvable tablets have a low water content, are therefore lightweight and easy to transport and store, while providing a highly concentrated dose of fabric softening efficacy.

[0010] One form of this tablet contains a surfactant and a cationic and / or amphoteric polymer softener. The tablet can also include additional surfactants, as well as polyvinyl alcohol (PVA), starch, and glycerol as structuring agents.

[0011] Compared to dissolvable detergent tablets, this tablet has a relatively high proportion of structuring agents, with levels of approximately 45 - 60%. Preferred structuring agents include starch and polyvinyl alcohol. These structuring agents help maintain the stability of the tablets and are advantageously compatible with polymer-based softeners. This compatibility, combined with the use of a high proportion of structuring agents, allows the softening active substances to remain in the matrix of the tablets rather than migrating out of them.

[0012] There is also provided a method for formulating the tablets of the present invention. A masterbatch slurry comprising a surfactant, a fabric softener, and a structuring agent (including PVA, starch, and glycerol) is mixed and spread on the surface of a heated drum to form a thin layer. As the drum rotates, the liquid evaporates from the masterbatch formulation on the drum surface, leaving a thin layer of the solid fabric softening composition. The tablets are then cut into single-use portions for consumers and packaged.

[0013] Thus, in one aspect of the present invention, there is provided a fabric softening soluble tablet product composed of a surfactant, a fabric softener based on zwitterionic and / or cationic polymers, and a base structuring agent. The soluble tablet can rapidly dissolve and dispense the fabric softening active substance in the wash load of a domestic washing machine. The soluble tablet can be placed in a dedicated dispenser box for fabric softener in a front-loading washing machine, but more preferably, it is directly added to the laundry load in the washing tub together with the detergent at the start of the wash cycle to achieve a better dissolution effect. The tablets are lightweight, have a low water content (usually below 10%), and remain stable for a long time under typical storage conditions at room temperature. In terms of softening efficacy and static elimination, the soluble tablets for fabric softening used in combination with the detergent exhibit at least comparable (and even better in some embodiments) performance compared to a commercially available liquid two-in-one detergent / fabric softener used as a benchmark.

[0014] In another aspect of the present invention, there is provided a method for manufacturing a fabric softening soluble tablet product.

[0015] In yet another aspect of the present invention, there is provided the use of such fabric softening soluble tablets for softening fabrics.

[0016] The present invention has many advantages. The soluble tablet product for fabric softening of the present invention is highly effective, can rapidly dissolve and disperse in water, and in terms of softening efficacy and static elimination, the soluble tablets for fabric softening of the present invention are at least comparable to the two-in-one detergent / fabric softener product used as a benchmark, and even better in some embodiments. The soluble tablets are lightweight and easy to transport and store. The soluble tablets use a cationic or zwitterionic polymer fabric softener, or a mixture of both. The soluble tablets are also stable at room temperature and do not suffer from the problem of migration or leaching of the fabric softening active substance from the solid matrix of the tablets. Thus, the present invention provides a beneficial balance among efficacy, ease of use, and stability.

[0017] These and other aspects of the present invention will become apparent from the following description. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention provides a novel fabric softening product in the form of a soluble tablet. The product is designed to be used simultaneously with a detergent in a household washing machine, preferably placed together with the detergent in the main drum of the washing machine having a laundry load. The soluble tablet has highly concentrated active ingredients, is convenient to use, stable at room temperature, and overcomes many inherent difficulties in formulating a solid soluble fabric softener.

[0020] As described above, the more widely used fabric softening active substances generally cannot be successfully incorporated into the form of a water-soluble tablet, which is usually attributed to the inherently poor water solubility of the softening active substances. To formulate into a tablet, it is necessary to mix the active ingredients into a slurry, which can then be made into a tablet that must remain stable until use. The inventors found through multiple formulation samples that most traditional fabric softening active substances fail at the pulping stage, and the mixture separates almost immediately; or fail at the tablet forming stage, whereby a tablet cannot be formed at all, or the fabric softening active substance is unstable once incorporated therein. Also, for ease of practical use by consumers, the size of the tablet must be small enough. Therefore, the active substance in the tablet must be in a concentrated form. Many fabric softening active substances are relatively dilute in terms of softening efficacy and cannot be incorporated in a concentrated form, and thus cannot be adapted to the solid tablet form without making the tablet too large and impractical.

[0021] To illustrate the above difficulties with known fabric softening active substances, a well-known silicone-based softening active substance is used as an example. It has been found that the slurry incorporating such silicone separates almost immediately. Known cationic surfactants and bentonite-based softening active substances, although effective in softening fabrics in large-volume formulations such as liquid fabric softeners, have a softening efficacy that is too dilute for them to be successfully incorporated into the slurry for tablet formulation. Esterquats and diamidoquats are also well-known and commonly used fabric softening active substances, and they can be successfully used to prepare the slurry and tablets. However, these active substances will rapidly leach out of the tablets after tablet formation, making them unusable. Other examples of known fabric softening active substances that exhibit one or more of the above manufacturing problems include: dialkyldimethylammonium chloride, cationic imidazolinium salts, cationic quaternary ammonium salts, and imidazolinium quats.

[0022] As described below, it has been found that when using a cationic or amphoteric polymer as a softener and compounding it with an anionic surfactant, the prepared tablets are stable and effective, and can provide effective softening efficacy when applied to fabrics.

[0023] Cationic polymer softener

[0024] Preferred embodiments of the formulations of the present invention may include an anionic surfactant, which is compounded with a cationic polymer as a softening component, and the cationic polymer is preferably a cationic polysaccharide. In particular, cationic inulin polysaccharide is most preferred.

[0025] Inulin is a type of fructan, belonging to soluble fiber, and exists in certain plant-based foods such as chicory and beets. It is known to form part of the waste products generated during the processing of sugar beets into food materials and has traditionally been discarded. However, companies under the COSUN Group have developed a method to process the inulin portion in the waste products into hydroxypropyltrimonium inulin. This ingredient has been commercially produced and sold under the brand name QUATIN. As a cationic biopolymer, it is suitable for addition to a variety of products such as personal care products, pharmaceuticals, and hard surface cleaners. It is environmentally friendly because it is both derived from natural raw materials and biodegradable, different from traditional fabric softening active substances that are usually fully synthetic or derived from petroleum or palm oil.

[0026] As described below, it has been found that when the QUATIN ingredient is used in the fabric softening formulation of the present invention, it can provide an effective softening effect for the fabric. When compounded with an anionic surfactant, QUATIN will form a coacervate that precipitates on the fabric, thereby imparting a more excellent soft touch to the fabric.

[0027] Although not wishing to be bound by theory, it is believed that the effectiveness of such cationic biopolymers as fabric softeners stems from their net positive charge characteristics and the effects produced when compounded with an anionic surfactant in an appropriate ratio. Generally, cationic biopolymers are water-soluble, and if added to the washing cycle, they will be washed away and unable to form a coating layer on the fabric. However, when compounded with an anionic surfactant, the cationic biopolymers, due to their net positive charge, will precipitate with the anionic surfactant to form solid particles, which are more likely to form a coating layer on the fabric surface.

[0028] The ingredients of the QUATIN series preferably used in the present invention include QUATIN 680 and QUATIN 1280, and there are differences in their degree of substitution and molecular weight. These specific ingredients have complementary effects on fabric softening. For example, as a larger molecule, QUATIN1280 tends to coat the fabric surface to provide a good touch. As a smaller molecule, QUATIN 680 will better penetrate the internal fibers of the fabric and generally provide a better antistatic effect. Those skilled in the art can adjust the ratio of different QUATIN active substances to determine the optimal ratio for the target fabric type.

[0029] As shown in the following detailed formulation, an effective fabric softening preparation can be made when the QUATIN component is used in combination with a specific amount of the anionic surfactant α-olefin sulfonate (AOS) at a ratio of about 1.7 - 2 parts AOS: 1 part total QUATIN. To the inventors' knowledge, inulin polysaccharides, such as those in the QUATIN series, have never been applied to any commercially available fabric softening composition in the form of a soluble tablet.

[0030] Other cationic polymers can also be used in place of QUATIN, but depending on their molecular weight, charge density, and degree of branching, the amount of anionic surfactant used needs to be adjusted accordingly to optimize the level of aggregation. Other cationic polymers that can be used in this way include other cationic polysaccharides (such as cationic guar gum), polyquaternized pyridinium salts derivatives, cationic silicone polymers, co-poly(4-vinylbenzyltrialkylammonium salts), co-poly(2-allyl-1-vinylimidazolium salts), co-poly(dimethylaminopropylmethacrylamide), polyquaternary ammonium salts, and quaternized polyimidazolines.

[0031] The use of a cationic polysaccharide such as inulin is beneficial for the stability of the tablet formulation. Most fabric softening active ingredients are difficult to immobilize in a solid matrix. Inulin itself is water-soluble, remains stable in tablet form, and is compatible with starch and PVA that provide the volume of the tablet. If other typical fabric softening active substances are made into tablet form, migration from the solid matrix often occurs, resulting in a greasy feeling on the surface of the tablet. This not only affects the consumer experience but also makes the packaged consumer product ineffective. Tablets in typical packaging are stacked, and the soluble tablets must not stick to each other excessively, otherwise it will be difficult for consumers to separate them without damage. Advantageously, by using the formulation of the present invention, the tablets can remain dry and intact, and no migration of the fabric softening active substance from the solid matrix is observed.

[0032] Amphoteric polymer fabric softener

[0033] Other preferred embodiments of the present invention may include a combination of an anionic surfactant and an amphoteric polymer as the fabric softening component, and the amphoteric polymer is preferably an amphoteric polyquaternary ammonium salt. In particular, the copolymer of diallyldimethylammonium chloride and acrylic acid is most preferred.

[0034] The inventors have successfully employed an amphoteric polymer fabric softening component commercially named NOVERITE 301, which is sold by LUBRIZOL Corporation. NOVERITE 301 is the trade name of polyquaternium-22, which is a copolymer of diallyldimethylammonium chloride and acrylic acid. This component has been previously used in the cosmetic field, but to the inventors' knowledge, this is the first time this component has been successfully applied to laundry products.

[0035] In some of the formulations described below, NOVERITE 301 is used in combination with additional polymers such as the cationic polymers Polyquaternium-7 and Polyquaternium-67 from Dow. When using a compliant active substance such as Polyquaternium-67, which is a polymer with long chains and a high charge density, the amount of surfactant used in the formulation must be carefully selected. For example, using too much of an anionic surfactant such as α-olefin sulfonate in a formulation containing Polyquaternium-67 will cause these components to precipitate out of solution and will not be able to properly produce the desired flocculation function. Alternatively, using too little anionic surfactant will prevent the initiation of the flocculation function.

[0036] When using an amphoteric polymer fabric softener such as NOVERITE 301 in the fabric softening formulations of the present invention, it can provide effective softening and static elimination for the fabric. Similar to the above explanation of the behavior of cationic softeners, when combined with a surfactant blend including an anionic surfactant, the amphoteric softener effectively forms a flocculated layer that deposits onto the fabric, making it softer and having a better feel.

[0037] Surfactant

[0038] The formulations of the present invention may also include a variety of surfactants. While it is important to include at least one anionic surfactant as the main surfactant, other surfactants can be nonionic, amphoteric, or a combination thereof. There are many options available in the field of household care products. An anionic surfactant that can be successfully used is α-olefin sulfonate. Other possible ones include sodium lauroyl sarcosinate (trade name EVERSOFT s-12), or linear alkylbenzene sulfonic acid, sodium fatty acid salts, sulfosuccinates of fatty acids, ammonium lauryl sulfate, sodium lauryl sulfate, and sodium laureth sulfate, all of which are available from multiple sources. Glyceryl polyether-6-cocoate is a surfactant that also acts as a release agent during the manufacturing process, making it difficult for the slurry to adhere to the kettle or drum, thus providing a dual advantage.

[0039] Additional compliant active substances

[0040] Other conditioning actives can be added in the formulation in a supplementary way to enhance the conditioning properties of the main conditioning active (cationic or amphoteric polymer). Small amounts (less than 2% by weight) of silicone-based conditioners such as dimethyl-polysiloxane, carboxyl-group-containing organopolysiloxanes, modified epoxyalkyl silicone compounds, clay-based conditioners such as bentonite, diamidoamine quats, and esterquats can be used. When used, it is important to keep the level of the additional conditioning actives low so that they are not likely to migrate out of the tablets and disrupt tablet integrity.

[0041] Structurant

[0042] As previously mentioned, PVA and starch are readily available structurants that can be used to form water-soluble tablets. Glycerol is another structurant with dual functions and can also be used as a processing aid. During the manufacturing process, glycerol is often referred to as a plasticizer because it can improve the fluidity and viscosity of liquid fabric conditioning formulations.

[0043] Release agent

[0044] It is also beneficial to add a release agent. As described further below, the tablet product can be made into a concentrated slurry, which is then spread on a heated drum and dried to form the tablet form. Therefore, it is beneficial to add additional ingredients such as a release agent so that the slurry does not adhere excessively to the manufacturing surface, such as the surface of the drum, or the interior of the industrial kettle used for slurry processing. Release agents that can be used in this way include the aforementioned Glycereth-6-cocoate (which is also a surfactant), which provides good release ability. Glycereth-6-cocoate is available from KAO Corporation and is sold under the brand name LEVENOL. Another release agent that can be successfully utilized is NEOBEE, which consists of medium-chain triglycerides and is available from STEPAN Corporation. There are many other release agents available on the market and can be successfully applied as long as they are compatible with other ingredients.

[0045] Additional ingredients

[0046] Optionally, a fragrance can also be added to impart a pleasant odor to the product and the fabric using the product. Encapsulated fragrances are particularly suitable for dry and concentrated products and are available from multiple sources.

[0047] It may also include a dispersant. The dispersant helps the components to be uniformly suspended in the liquid phase of the preparation. In particular, the inventors have found further beneficial effects when liquid cellulose (CELLULON R-25 sold by CP-Kelco) is included as a dispersant. The in-house team tests observed that when cellulose is used, the fragrance can tolerate the heat drying step. After being taken out of the dryer, the fabric still continuously emits fragrance, and it can still be detected during long-term use or wearing of the fabric.

[0048] Therefore, using a dispersant has a surprising result that the fragrance on the fabric lasts longer. It is believed that the dispersant causes the encapsulated fragrance to be more deeply embedded in the fibers of the fabric, thereby protecting these encapsulated particles during the heat drying process. Then, when the fabric is subsequently further processed or worn, the encapsulated particles continuously break, thereby releasing more fragrance. This results in a more lasting sensory benefit, which is attractive to the users of this product.

[0049] In a preferred embodiment of the preparation, before being dried into tablets on a heating drum, in the slurry, cationic inulin polysaccharide is provided in a percentage of 5.00 - 20.00% by weight, more preferably 10.00 - 15.00% by weight, and is the main source of the softening effect of the preparation. A surfactant is also included, and the specific amount depends on the target surfactant. If AOS is used together with the cationic inulin polysaccharide listed in the following preparation, AOS should be provided at a ratio of approximately 1.5 - 2:1. Referring to the range of cationic inulin polysaccharide provided above, AOS should preferably be provided at a corresponding weight percentage of 15.00 - 30.00%, or more preferably 18.00 - 25.00%.

[0050] In a further preferred embodiment of the preparation, before being dried into tablet form on a heating drum, the components in the slurry are provided as follows, wherein the amphoteric polymer is 0.5 - 5.0% by weight, more preferably 1.0 - 2.0% by weight, thereby being the main source of the softening effect of the preparation. A surfactant is also included, and the specific amount depends on the surfactant involved.

[0051] Structuring agents such as PVA, glycerol, and starch can be included in the slurry in a total amount of 15.0 - 30.0% by weight. Approximately 35.0 - 65.0% by weight of water is also included.

[0052] The following shows an example of the preparation of the slurry prepared according to the manufacturing method and subsequently dried. The corresponding amounts of each component in the 100mm x 100mm soluble tablets made from this slurry are also provided. In the preparation, certain components such as fragrance, pH regulator, dispersant, and release agent are optional.

[0053] Table 1 - Preparation FB5

[0054]

[0055] Examples of flavoring agents for the slurry are shown below. The corresponding amounts of each component in the soluble tablets made from the slurry are also provided.

[0056] Table 2 - Formulation S111

[0057]

[0058] Another example of a flavoring agent for the slurry is shown below, which uses an amphoteric surfactant. The corresponding amounts of each component in the soluble tablets made from the slurry are also provided.

[0059] Table 3 - Formulation AP1

[0060]

[0061]

[0062] Another example of a slurry formulation is shown below, which includes a release agent as a processing aid. The corresponding amounts of each component in the soluble tablets made from the slurry are also provided.

[0063] Table 4 - Formulation AC2

[0064]

[0065]

[0066] Formulation method

[0067] To formulate the fabric softening tablets of the present invention, a high - viscosity slurry was prepared according to formulations such as those described above. The industrial batch scale of this slurry can be in the range of 50 - 60 kg and is mixed using a standard homogenizing mixer at ambient temperature for at least 40 minutes. The viscosity of the slurry is in the range of 41.5 cpas, and the pH is adjusted to about 4.7. Citric acid can be used for pH adjustment. Citric acid also has the additional advantage of being able to eliminate the unpleasant fishy smell that may originate from volatile amines released in the slurry and the resulting tablets. Citric acid reacts with amines to form salts, which remain in solution, thus eliminating the odor.

[0068] The slurry prepared under the above conditions will be stable for 2 - 3 days in a closed container.

[0069] The slurry prepared according to the general method described above can then be coated onto the surface of a rotating heated drum, where the slurry forms concentrated fabric softening preparation tablets. Tablets having a thickness of about 0.7 mm + / - 0.2 mm can be formed. The tablets can then be processed into single-use portions. For example, it is convenient to cut the tablets into a 2-use portion having dimensions of about 100 mm x 100 mm, with a tear line provided in the center of the sheet to facilitate the user separating it into two single-use portions at a later time for softening medium-sized laundry loads. A standard industrial batch size slurry of 50 - 60 kg will produce thousands of tablets, corresponding to more than 10,000 single-use portions. The weight of each tablet is about 3.2 g + / - 0.5 g. Tests have shown that the tablet completely dissolves in stirred cold water in only 20 - 25 seconds.

[0070] As described above, the present invention corresponds to a solid soluble tablet containing a fabric softener, which is prepared by evaporating most of the water from a slurry made according to any of the foregoing preparations. The solid soluble tablet can comprise, by weight percentage of the final preparation:

[0071] (a) about 45.0 - 60.0% structurant;

[0072] (b) about 20.0 - 30.0% anionic surfactant;

[0073] (c) about 10.0 - 15.0% cationic polymer, preferably a polysaccharide;

[0074] (d) water;

[0075] Provided that the sum of (a) - (d) must be 100%.

[0076] The present invention also corresponds to a soluble fabric softening tablet comprising, by weight percentage of the final preparation:

[0077] (a) about 45.0 - 60.0% structurant;

[0078] (b) about 20.0% anionic surfactant;

[0079] (c) about 10.0 - 12.0% cationic polymer, preferably a polysaccharide;

[0080] (d) water;

[0081] Provided that the sum of (a) - (d) must be 100%.

[0082] The present invention also corresponds to a soluble fabric softening tablet comprising, by weight percentage of the final preparation:

[0083] (a) Approximately 45.0 - 60.0% structuring agent, including polyvinyl alcohol, starch, and glycerol;

[0084] (b) Approximately 20.0% anionic surfactant, including alpha - olefin sulfonate;

[0085] (c) Approximately 10.0 - 12.0% cationic polysaccharide, including inulin polysaccharide;

[0086] (d) Approximately 2.0 - 5.0% release agent;

[0087] (e) Water;

[0088] Provided that the sum of (a) - (e) must be 100%.

[0089] The present invention also corresponds to a soluble fabric softening tablet, comprising, by weight percentage of the final formulation:

[0090] (a) Approximately 45.0 - 60.0% structuring agent, including polyvinyl alcohol, starch, and glycerol;

[0091] (b) Approximately 20.0% anionic surfactant, including alpha - olefin sulfonate;

[0092] (c) Approximately 10.0 - 12.0% cationic polysaccharide, including inulin polysaccharide;

[0093] (d) Approximately 2.0 - 5.0% release agent;

[0094] (e) Approximately 0.5 - 0.8% citric acid;

[0095] (f) Water;

[0096] Provided that the sum of (a) - (f) must be 100%.

[0097] The present invention also corresponds to a soluble fabric softening tablet, comprising, by weight percentage of the final formulation:

[0098] (a) Approximately 45.0 - 60.0% structuring agent, including polyvinyl alcohol, starch, and glycerol;

[0099] (b) Approximately 20.0% anionic surfactant, including alpha - olefin sulfonate;

[0100] (c) Approximately 10.0 - 12.0% cationic polysaccharide, including inulin polysaccharide;

[0101] (d) Approximately 2.0 - 5.0% release agent;

[0102] (e) Approximately 0.8% citric acid;

[0103] (f) Approximately 1.0% fragrance;

[0104] (g) Approximately 0.3% dispersant;

[0105] (h) Water;

[0106] Provided that the sum of (a)-(h) must be 100%.

[0107] The present invention also corresponds to a soluble fabric softening tablet, comprising, based on the weight percentage of the final formulation:

[0108] (a) Approximately 50.0 - 60.0% structurant;

[0109] (b) Approximately 25.0 - 30.0% surfactant;

[0110] (c) Approximately 1.0 - 5.0% of an amphoteric polymer;

[0111] (d) Water;

[0112] Provided that the sum of (a)-(d) must be 100%.

[0113] The present invention also corresponds to a soluble fabric softening tablet, comprising, based on the weight percentage of the final formulation:

[0114] (a) Approximately 50.0 - 60.0% structurant;

[0115] (b) Approximately 25.0 - 30.0% surfactant;

[0116] (c) Approximately 1.0 - 5.0% of an amphoteric polymer;

[0117] (d) Water;

[0118] Provided that the sum of (a)-(d) must be 100%.

[0119] The present invention also corresponds to a soluble fabric softening tablet, comprising, based on the weight percentage of the final formulation:

[0120] (a) Approximately 50.0 - 60.0% structurant;

[0121] (b) Approximately 25.0 - 30.0% surfactant;

[0122] (c) Approximately 2.0 - 3.0% amphoteric polymer;

[0123] (d) Water;

[0124] Provided that the sum of (a)-(d) must be 100%.

[0125] The present invention also corresponds to a soluble fabric softening tablet, comprising, based on the weight percentage of the final formulation:

[0126] (a) Approximately 50.0 - 60.0% structuring agent;

[0127] (b) Approximately 25.0 - 30.0% surfactant, selected from one or more of anionic, amphoteric, and nonionic surfactants;

[0128] (c) Approximately 2.0 - 3.0% amphoteric polymer, preferably a copolymer;

[0129] (d) Water;

[0130] Provided that the sum of (a) - (d) must be 100%.

[0131] The present invention also corresponds to a soluble fabric softening tablet, comprising, by weight percentage of the final formulation:

[0132] (a) Approximately 50.0 - 60.0% structuring agent, selected from one or more of polyvinyl alcohol, starch, and glycerol;

[0133] (b) Approximately 25.0 - 30.0% surfactant, selected from one or more of anionic, amphoteric, and nonionic surfactants;

[0134] (c) Approximately 2.0 - 3.0% amphoteric polymer, preferably comprising polyquaternium - 22;

[0135] (d) Approximately 1.5 - 3.0% release agent;

[0136] (e) Water;

[0137] Provided that the sum of (a) - (e) must be 100%.

[0138] The present invention also corresponds to a soluble fabric softening tablet, comprising, by weight percentage of the final formulation:

[0139] (a) Approximately 50.0 - 60.0% structuring agent, selected from one or more of polyvinyl alcohol, starch, and glycerol;

[0140] (b) Approximately 25.0 - 30.0% surfactant, selected from one or more of anionic, amphoteric, and nonionic surfactants;

[0141] (c) Approximately 2.0 - 3.0% amphoteric polymer, preferably comprising polyquaternium - 22;

[0142] (d) Approximately 1.5 - 3.0% release agent;

[0143] (e) Approximately 1.0% fragrance;

[0144] (f) Approximately 0.1% dispersant;

[0145] (g) Water;

[0146] Provided that the sum of (a)-(g) must be 100%.

[0147] As used herein, the term "about" means an amount that is 10% or less, and preferably 5% or less, of the indicated amount, where the amount is greater than or less than the indicated amount. This applies to all numbers in this specification that indicate amounts or proportions of materials, reaction conditions, or physical properties and dimensions of materials.

[0148] The present invention also corresponds to a method for manufacturing the above-mentioned soluble tablets as described above.

[0149] When manufactured according to the method described herein, the present invention also corresponds to the above-mentioned soluble tablets.

[0150] The present invention also corresponds to a soluble fabric softening tablet that contains an encapsulated fragrance for providing a fragrance to the fabric, and a dispersant is also incorporated into the fabric to increase the adsorption of the fabric to the fragrance agent.

[0151] The present invention also corresponds to the use of the above-mentioned soluble tablets for softening fabrics.

[0152] Stability test

[0153] The tablets of the present invention can be provided in standard boxed or envelope-type packaging. When stacked and stored, even after long-term storage at typical ambient humidity and temperature, the tablets do not stick to each other. No migration of the active ingredient from the tablets was observed. Under conditions of very high humidity such as tropical conditions, the tablets can absorb water from the air and become sticky, but they still remain stable and are easy to separate.

[0154] For soluble tablets, the standard test procedure in the art is to place the stacked tablets in their recommended packaging and incubate them in an oven set at 60 °C for 21 days. After incubation, the tablets are inspected to determine whether any components have separated from the solid matrix of the tablets and formed a coating on the outer side of the tablets or caused adjacent tablets to stick to each other. If the tablets maintain their integrity at 60 °C for 21 days, they are considered to have a shelf life of at least two years under the temperature and humidity conditions of a standard environment.

[0155] Each formulation of the above-mentioned soluble tablets for fabric softener of the present invention was tested in the above manner and was found to survive the 21-day incubation period at 60 °C intact. Qualitative observations confirmed that no components migrated from the solid matrix, and the tablets remained touch-dry and did not stick to each other. Therefore, the tablets of the present invention have been proven to have a shelf life of at least two years under ambient temperature and humidity conditions.

[0156] Efficacy test - Softness

[0157] Efficacy tests were also conducted to evaluate the fabric softening efficacy and anti-static ability of the tablets of the present invention. A third-party independent laboratory conducted the tests in accordance with the HCPA DCC-13 – Performance Test Methods and Guidelines - Fabric Softeners. In accordance with the published test method, washing and drying tests were carried out on a standard laundry load consisting of looped cotton hand towels in a specified Whirlpool washing machine and dryer. The agitated laundry loads were compared: TIDE original detergent (42.5 mL), without softener; ATTITUDE two-in-one laundry detergent & fabric softener (30 ml); and TRUEARTH strip laundry detergent (1 strip), combined with a fabric softening tablet prepared according to the present invention, identified by the codes FB5, AP1, and AC2. The doses selected for each detergent and softener were based on the manufacturer's recommendations for small loads.

[0158] To test softness, after washing and drying, the relative softness of the hand towels was evaluated. Before evaluating softness, the hand towels were conditioned in a constant humidity chamber for at least 24 hours. Then panelists were asked to give the hand towels a score from 1 to 5, where 1 had the least softness and 5 was the softest. After each test, the scores were totaled and averaged to give a single score for each product.

[0159] The results are shown below:

[0160] Table 5: Relative softness of hand towels - Test 1

[0161]

[0162] Test 1 shows that the fabric softening tablets of the present invention have performance comparable to that of the two-in-one detergent and fabric softener used as the market benchmark, where AP1 has a greater softness than the market benchmark product.

[0163] Table 6: Relative softness of hand towels - Test 2

[0164]

[0165] Test 2 shows that the tablet FB5 of the present invention achieved better softness than the benchmark product.

[0166] As shown in the test results, the control without added softening active substance had the lowest softness score. The comparison standard used in each test was the two-in-one detergent and fabric softener. The fabric softening tablets of the present invention, when put into the washing cycle together with the standard detergent tablets each time and run for one cycle, achieved a softness score equivalent to or better than that of the benchmark product.

[0167] These results indicate that the fabric softening tablets of the present invention are quite effective and, in some cases, are more effective in terms of softening efficacy compared to a two-in-one detergent fabric softener product used as a benchmark. The results are statistically significant --, and the standard deviation is less than + / -0.5.

[0168] Efficacy Test - Static Elimination

[0169] To test static elimination, after washing and drying, the relative peak static charge of sheets made of two materials (cotton and cotton-polyester blend) was evaluated. After the sheets were washed, they were placed in a standard tumble dryer at a high temperature setting for 50 minutes. Immediately after removing the towels, the peak static charge was measured and recorded. The higher the peak static charge, the greater the amount of static electricity accumulated on the fabric. After each test, the scores were added and averaged to give a single rating for each product.

[0170] The results for the tablets made according to formulation AC2 are shown below.

[0171] Table 7: Peak Static Charge on Washed Fabrics

[0172]

[0173]

[0174] As shown by the test results, in the two benchmark samples, the static charge was not reduced. However, by using the tablets AC2 of the present invention, the static charge was significantly reduced.

[0175] These results demonstrate that the AC2 fabric softening tablets of the present invention are more effective than the benchmark products, including standard two-in-one detergent fabric softener products, in reducing static charge. The results are statistically significant, and the standard deviation is less than + / -0.5.

[0176] Tensile Strength Test

[0177] The protective effect of a formulation on fabrics was also tested. It is known that fabric fibers weaken over time under repeated washing and drying conditions. Standard test methods such as ASTM D2261-13 (Standard Tear Strength Test) can be used to test laundry formulations to determine whether they have any protective effect on fabrics. In this test, fabric samples were washed and dried for five cycles using a specific model of washing machine and dryer, and then tested in a tensile testing machine to determine the amount of force required to tear the fabric, measured in Newtons. The average value for each test was calculated. The greater the force required, the greater the fabric strength.

[0178] The fabrics tested were polyester and cotton. As shown below, the protective effect of the fabric softening tablets of the present invention (formulation FB5) on polyester fabrics can be seen.

[0179] Table 8: Tensile Tear Strength Test of FB5

[0180]

[0181]

[0182] As shown above, for polyester, tear resistance is improved, as reflected by the higher force required to tear the fabric sample, but not for cotton. For polyester, simply washing the fabric in detergent does cause the fabric to weaken, as shown by comparing the unwashed control with TIDE and TRU EARTH without fabric softener. Compared to the benchmark product ATTITUDE 2-in-1, which also contains a fabric softener, adding the fabric softener of the present invention (formulation FB5) provides a statistically significant enhancement for polyester fibers. This may be because the fabric softener formulated in FB5 coats the fibers to provide a protective effect. This is another advantage of the fabric softening formulation of the present invention.

[0183] Summary

[0184] Accordingly, the present invention has been demonstrated to provide a highly concentrated and stable fabric softener in the form of an easily soluble tablet. In addition to being in the convenient tablet form that is easy to store and more lightweight for transportation, the product is also environmentally friendly because the soluble tablet form means fabric softening with less waste generation. Therefore, compared to traditional fabric softening products, the product of the present invention has a significant improvement in environmental impact.

[0185] Although specific embodiments of the present invention have been shown 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, all such changes and modifications fall within the scope of the present invention and are covered by the appended claims.

Claims

1. A water-soluble tablet for softening fabrics, comprising by weight: (a) about 45.0 - 60.0% of a structurant; (b) about 20 - 30% of a surfactant, which comprises one or more anionic surfactants; (c) about 2 - 15% of a fabric softening active substance, which comprises an amphoteric polymer and / or a cationic polymer; and (d) the balance being water; wherein the fabric softening active substance remains stably bound after the formation of the tablet.

2. The water-soluble tablet according to claim 1, wherein the structurant comprises one or more selected from the group consisting of polyvinyl alcohol, starch, and glycerol.

3. The water-soluble tablet according to claim 1, wherein the surfactant comprises one or more selected from the group consisting of α-olefin sulfonate, sodium lauroyl sarcosinate, glycerol polyether-6-cocoate, cocamidopropyl hydroxysultaine, linear ethoxylated alcohol, sodium lauryl sulfate, sodium lauryl sulfoacetate, disodium laureth sulfosuccinate, linear alkylbenzene sulfonic acid, fatty acid sodium salt, fatty acid sulfosuccinate, ammonium lauryl sulfate, sodium lauryl sulfate, and sodium laureth sulfate.

4. The water-soluble tablet according to claim 1, wherein the amphoteric polymer comprises one or more polyquaternium salts.

5. The water-soluble tablet according to claim 4, wherein the one or more polyquaternium salts comprise a copolymer.

6. The water-soluble tablet according to claim 5, wherein the copolymer is a copolymer of diallyldimethylammonium chloride and acrylic acid.

7. The water-soluble tablet according to claim 1, wherein the cationic polymer comprises one or more selected from the group consisting of inulin polysaccharide, cationic guar gum, polyquaternized pyridinium salt derivatives, cationic silicone polymers, co-poly(4-vinylbenzyl trialkylammonium salts), co-poly(2-allyl-1-vinylimidazolium salts), co-poly(dimethylaminopropyl methacrylamide), polyquaternium salts, and quaternized polyimidazolines.

8. The water-soluble tablet according to claim 7, wherein the cationic polymer is inulin polysaccharide.

9. The water-soluble tablet according to claim 1, which further comprises a release agent.

10. The water-soluble tablet according to claim 1, which further comprises an encapsulated fragrance.

11. The water-soluble tablet according to claim 8, which further comprises a dispersant.

12. The water-soluble tablet according to claim 1, which further comprises one or more additional softening active substances selected from the group consisting of silicone-based softeners, ester quaternary ammonium salts, dialkyldimethylammonium chloride, cationic imidazolinium salts, cationic quaternary ammonium salts, bentonite or other clay-based fabric softeners, polyquaternium salts, and imidazolinium quaternary ammonium salts.

13. The water-soluble tablet for softening fabrics according to claim 1, comprising by weight: (a) 25.7% of polyvinyl alcohol; (b) 15.9% of starch; (c) 4.5% of glycerol; (d) 21.5% of α-olefin sulfonate; (e) 4.5% of glycerol polyether-6-cocoate; (f) 11.5% of inulin polysaccharide; (g) 0.8% citric acid; and (h) the balance being water, wherein the inulin polysaccharide remains stably bound after formation of the tablet.

14. The water-soluble tablet for softening fabrics according to claim 1, comprising by weight: (a) 24.5% polyvinyl alcohol; (b) 21.1% starch; (c) 4.3% glycerol; (d) 18.8% α-olefin sulfonate; (e) 4.2% glycerol polyether-6-cocoate; (f) 10.8% inulin polysaccharide; (g) 0.7% citric acid; (h) 2.2% medium-chain triglyceride; (i) 0.3% cellulose; and (j) the balance being water, wherein the inulin polysaccharide remains stably bound after formation of the tablet.

15. The water-soluble tablet for softening fabrics according to claim 1, comprising by weight: (a) 24.6% polyvinyl alcohol; (b) 22.4% starch; (c) 11.8% glycerol; (d) 4.5% α-olefin sulfonate; (e) 19.7% sodium lauroyl sarcosinate; (f) 5.0% glycerol polyether-6-cocoate; (g) 3.0% polyquaternium-22; (h) 1.7% medium-chain triglyceride; (i) 1.0% fragrance; (j) 0.1% cellulose; and (k) the balance being water wherein polyquaternium-22 remains stably bound after formation of the tablet.

16. The water-soluble tablet for softening fabrics according to claim 1, comprising by weight: (a) 27.1% polyvinyl alcohol; (b) 22.7% starch; (c) 10.0% glycerol; (d) 20.0% cocamidopropyl hydroxysultaine; (e) 1.1% linear ethoxylated alcohol; (f) 0.8% sodium lauroyl sarcosinate; (g) 4.8% glycerol polyether-6-cocoate; (h) 2.0% polyquaternium-22; (g) 1.2% polyquaternium-67; (h) 3.0% medium-chain triglyceride; (j) 1.0% fragrance; (k) 0.1% cellulose; and (j) the balance being water, wherein the polyquaternium remains stably bound after formation of the tablet.

17. Use of the water-soluble tablet according to any one of the preceding claims for providing a softening effect to fabrics.

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