Detergent bar composition

Abstract

The present invention relates to detergent bars. Specifically, the present invention relates to a laundry detergent bar composition having no polyphosphate builders. The present inventors have found that disclosed process for preparing a solid laundry detergent bar composition which involves a step of complete neutralization of the acid precursor of anionic surfactant with specific neutralizing agent and a step of contacting a phosphorous based acid with an aluminium containing alkaline compound to form an aluminium-phosphate complex provides a laundry detergent bar composition which has desirable bar properties and sensorial properties even when the laundry detergent bar composition has 0 wt.% polyphosphate builder, more specifically when the laundry detergent bar composition has 0 wt.% STPP. The laundry detergent bar deliver superior sensory properties such as lather, bar feel, skin feel, colour of the bar, without altering the processability and physical properties of the bar.

Description

[0001] DETERGENT BAR COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to a process for preparing a shaped solid article particularly a process for preparing a detergent bar composition and a detergent bar thereof. Specifically, the present invention relates to a process for preparing a laundry detergent bar composition having no polyphosphate builder.

[0004] Background of the Invention

[0005] In many countries, where mechanical washing machines are not common, laundry detergent bars are used for cleaning fabrics. Laundry detergent bar composition typically includes a synthetic anionic surfactant such as the alkali metal salt of an alkyl benzene sulfonic acid or alkali metal salt of an alkyl sulfate and one or more alkaline builders such as alkali metal polyphosphates, carbonates, or silicates.

[0006] Sodium tri-polyphosphate (STPP) is another important ingredient present in a laundry detergent bar composition. STPP has always been considered a good builder and it also acts as a structurant in a laundry detergent bar composition. It helps in preventing breakage and promotes quick dissolution of the bars. It also contributes to the alkalinity, anti-redeposition and cleaning efficiency of bars. Moreover, STPP also helps in retaining high levels of water in bound form which ensures that the bar has good sensory properties.

[0007] STPP provides these benefits when present in the laundry detergent composition in an amount ranging from 5 wt.% to 25 wt.% in the detergent bar composition. At these high concentration levels STPP has adverse environmental effects. Specifically, phosphate leakage to the sewage system can lead to eutrophication. This causes excessive algal bloom, decreasing water quality and reduced fish population. Due to the mentioned disadvantages of STPP there is a need to lower the usage of STPP in the production of laundry detergent bar composition.

[0008] W02001 / 42413 A1 (Unilever) discloses a detergent bar composition having 10 wt.% to 60 wt.% detergent active, 0.5 wt.% to 40 wt.% colloidal aluminium hydroxide-phosphate (Al-complex), from 0 wt.% to 30 wt.% detergent builder, 0 wt.% to 60 wt.% inorganic particulate material and 8 wt.% to 35 wt.% water. US2001 / 0031711 A1 (Unilever) discloses a detergent bar composition comprising 15 wt.% to 70 wt.% total fatty matter, 0.5 wt.% to 40 wt.% colloidal aluminium hydroxide-phosphate complex, and 10 wt.% to 50 wt.% water.

[0009] Nonetheless consumers prefer laundry detergent bar composition which provides good cleaning performance on fabrics. Detergent bar composition must also provide acceptable foaming performance at difference water temperature and water hardness. In addition to this, the laundry detergent bar composition must have acceptable in-use wear rates, hardness, durability, and feel.

[0010] Reducing or total removal of STPP to address the eutrophication issue has long been a challenge to formulators as any reduction in the amount of STPP in the detergent bar composition will negatively impact the bar properties such as physical strength of the bar which is required for retaining their structural integrity during handling, transport, and use. The hardness of the bar, at the time of manufacture and subsequently, is an especially important property. Any reduction in the levels of the STPP in a laundry detergent bar composition also negatively impacts the sensorial properties. Also, in bar which have higher levels of water content STPP plays an important role in providing the required bar density, size, and ability to easily deposit on the fabric with minimal manual effort by the consumer.

[0011] Accordingly, there remains a need for a laundry detergent bar composition which has no STPP builder, and which still maintains acceptable in-use wear rate, hardness, durability, rapid drying, density, low smear, and good sensorial properties while remaining eco-friendly.

[0012] Summary of the Invention

[0013] The present inventors have found that disclosed process for preparing a solid laundry detergent bar composition which involves a step of neutralization of the acid precursor of anionic surfactant with alkali metal carbonate salt and / or aluminium containing alkaline compound and then a step of contacting a phosphorous based acid, followed by an aluminium containing alkaline compound to form an aluminium-phosphate complex provides a laundry detergent bar composition which has desirable bar properties and sensorial properties even when the laundry detergent bar composition has 0 wt.% polyphosphate builder, more specifically when the laundry detergent bar composition has 0 wt.% STPP. The process also provides a solid laundry detergent article which is structured and holds its shape even when the composition has or 0 wt.% polyphosphate builder and provides good sensorial properties.

[0014] It was surprisingly found that when the step of contacting a phosphorous based acid with an aluminium containing alkaline compound to form an aluminium-phosphate complex is conducted in presence of the in-situ formed anionic surfactant which is completely neutralized by an alkali metal carbonate salt and / or aluminium containing alkaline compound, the resulting laundry detergent bar composition has good bar properties even when it is formulated with a total moisture content ranging from 18 wt.% to 35 wt.% and where the laundry detergent bar composition has 0 wt.% polyphosphate builder, more particularly 0 wt.% STPP.

[0015] It was further surprisingly found that the laundry detergent bar composition according to the present invention having 0 wt.% polyphosphate builder and an in-situ formed aluminiumphosphate complex provides good detergency at various water-hardness conditions even at low levels or in absence of a builder, preferably in absence of a builder selected from the group consisting of precipitating builder.

[0016] Disclosed process for preparing a laundry detergent bar composition which includes no STPP builder, was found to deliver superior sensory properties such as lather, bar feel, skin feel, and colour of the bar. The laundry detergent bar prepared by the disclosed process was found to be easily processable and provides good physical properties to the bar.

[0017] According to a first aspect of the present invention disclosed is a process for preparing a solid laundry detergent article comprising: i. an anionic surfactant; ii. an aluminium-phosphate complex; iii. 0 wt.% to 30 wt.% filler; and, iv. 0 wt.% polyphosphate builder, wherein the process comprises the steps of: i. admixing in any order an acid precursor of anionic surfactant and a neutralizing agent selected from the group consisting of an alkali metal carbonate, aluminium containing alkaline compound or mixtures thereof to effect complete neutralization of the acid precursor of anionic surfactant to form an anionic surfactant salt; ii. adding phosphorous based acid compound to the solution to adjust the pH ranging from 1 to 5, followed by the addition of aluminium containing alkaline compound to form a mixture having aluminium-phosphate complex and anionic surfactant salt; iii. optionally adding a filler; iv. shaping the mixture to form a solid laundry detergent article.

[0018] According to a yet another aspect of the present invention disclosed is a process for preparing a solid laundry detergent bar composition comprising: i. an anionic surfactant; ii. an aluminium-phosphate complex; iii. 0 wt.% to 30 wt.% filler; and, iv. 0 wt.% polyphosphate builder, wherein the process comprises the steps of: i. admixing in any order an acid precursor of anionic surfactant and a neutralizing agent selected from the group consisting of an alkali metal carbonate, aluminium containing alkaline compound or mixtures thereof to effect complete neutralization of the acid precursor of anionic surfactant to form an anionic surfactant salt; ii. adding phosphorous based acid compound to the solution to adjust the pH ranging from 1 to 5, followed by the addition of aluminium containing alkaline compound to form a mixture having aluminium-phosphate complex and anionic surfactant salt; iii. optionally adding a filler; iv. shaping the mixture to form a solid laundry detergent bar composition.

[0019] The "phosphorus-based acid compound" may be selected from metaphosphoric, hypo-phosphoric, orthophosphoric, pyrophosphoric or polyphosphoric acid; or phosphorous, hypo-phosphorous or pyro phosphorous acid. The preferred phosphorus-based acid is orthophosphoric, pyrophosphoric, phosphorous, phosphoric acid, and hypo phosphorous acid or mixtures thereof. Most preferably the "phosphorus-based acid compound" is phosphoric acid.

[0020] The term "laundry detergent bar composition" as used herein relates to a laundry detergent in solid state that is useful for cleaning textiles, fabrics, and nonwovens. Laundry detergent bar composition may be in the form of a solid bar, individual pellet or other solid-state configurations well known to the person skilled in the art.

[0021] These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word “about”. Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

[0022] Detailed Description of the Invention

[0023] Process for preparing the laundry detergent bar composition:

[0024] According to a first aspect disclosed is a process for preparing a solid laundry detergent article including the steps as described herein below. Preferably the solid laundry detergent article is a laundry detergent bar composition. According to a first aspect disclosed is a process for preparing a laundry detergent bar composition including the steps as described herein below.

[0025] Step (i): Neutralizing an acid precursor of an anionic surfactant

[0026] According to the first aspect of the present invention disclosed is the step of admixing in any order an acid precursor of anionic surfactant and a neutralizing agent selected from the group consisting of an alkali metal carbonate salt, aluminium containing alkaline compound or mixtures thereof to effect complete neutralization of the acid precursor of anionic surfactant to form an anionic surfactant salt.

[0027] Acid precursor of anionic surfactant

[0028] The acid precursor of anionic surfactant according to the present invention is completely neutralized to its salt form using a neutralizing agent selected from the group consisting of alkali metal carbonate salt, aluminium containing alkaline compound and mixtures thereof.

[0029] Suitable acid precursor of anionic surfactant are well known to those skilled in the art. More preferably the acid precursor of anionic surfactant is a liquid acid precursor. Examples of suitable acid precursor of anionic surfactant includes alkyl and aryl sulphonic acids andderivatives thereof, preferably alkylbenzene sulphonic acid, particularly linear alkylbenzene sulphonic acid having an alkyl chain length of C8to C22, preferably C10to C20, still preferably C11to C15; primary and secondary alkyl sulphuric acid, particularly C12 to C15primary alkyl sulphuric acid. Preferably, the liquid acid precursor of anionic surfactant is an alkyl benzene sulphonic acid, preferably linear alkylbenzene sulphonic acid (LAS acid or HLAS), more preferably having an alkyl chain length of C8to C20, still preferably C10to C20. It is highly preferred that the liquid acid precursor of the anionic surfactant comprises an alkyl benzene sulphonic acid (linear or branched), preferably C8to C20linear alkyl benzene sulphonic acid. Preferably the alkyl benzene sulphonic acid is linear or branched, substituted or unsubstituted, C8to C20alkyl benzene sulphonate. Highly preferred C8to C20alkyl benzene sulphonic are linear C10to C13 alkylbenzene sulphonic acid. Especially preferred are linear C10to C13alkylbenzene sulphonic acid obtained, by sulphonating commercially available linear alkyl benzenes (LAB); suitable LAB include low 2-phenyl LAB, such as those supplied by Sasol under the tradename Isochem® or those supplied by Petresa under the tradename Petrelab®, other suitable LAB include high 2-phenyl LAB, such as those supplied by Sasol under the tradename Hyblene®. Preferably, the anionic surfactant precursor is LAS acid which yields the corresponding linear alkyl benzene sulphonate (LAS) upon neutralisation.

[0030] Also included within the scope of the present invention are the acid precursors which includes alkyl ether sulphuric acid; olefin sulphonic acid (preferably C8to C24; alkyl xylene sulphonic acid; alkane sulphonic acid, dialkyl sulphosuccinic acid; fatty acid ester sulphonic acid and mixtures thereof. Preferably the acid precursor of anionic surfactant is a non-soap anionic surfactant acid precursor.

[0031] More preferably the acid precursor is linear alkyl benzene sulphonic acids (LAS acids) which upon neutralisation forms linear alkyl benzene sulphonates (LAS). Preferably, any LAS anionic surfactant has an alkyl chain length of C8to C18, more preferably C9to C15and most preferably C10to C14. Also preferred are alkyl and / or alkenyl sulphuric acid half-esters (i.e. , the sulphation products of primary alcohols) which upon neutralization forms alkyl and / or alkenyl sulphates (PAS) . PAS having an alkyl chain length of C10to C22, preferably C12to C14are preferred.

[0032] The acid precursor of anionic surfactant can either be in the form of an aqueous preparation or in anhydrous form, more preferably the anionic surfactant is in the form of an aqueous preparation. If added as an aqueous preparation, it is preferred that the water content does not exceed 25 wt.% more preferably not exceeding 10 wt.% of the acid precursor of anionic surfactant.

[0033] Preferably the acid precursor of anionic surfactant has a purity ranging from 85% to 99%, that is it comprises from 85% to 99%, more preferably 90% to 98% acid precursor of anionic surfactant, the remaining ingredients include liquid carrier (water or other inorganic solvent), sulphuric acid, non-detergent organic matter such as unreacted linear alkyl benzene. More preferably the acid precursor of anionic surfactant has a purity from 90% to 98%. Preferably the liquid acid precursor of anionic surfactant is aqueous. Preferably the liquid acid precursor of the anionic surfactant includes from 1 wt.% to 10 wt.% water, still preferably less than 10 wt.%.

[0034] The acid precursor of the anionic surfactant is preferably provided in a liquid form. Specifically, such liquid acid precursor of anionic surfactant is characterized by a viscosity ranging from about 0.1 Pa.S to about 10 Pa.S, preferably from about 0.1 Pa.S to about 5 Pa.S, more preferably from about 0.2 Pa.S to about 0.5 Pa.S, when measured at 50°C and at a shear rate of 25s-1.

[0035] The acid precursor of the anionic surfactant may be linear or branched. Preferably it may be substituted or un-substituted. Preferably the liquid acid precursor of the anionic surfactant may be derived from petrochemical material or biomaterial.

[0036] Preferably the amount of acid precursor of anionic surfactant present in step (i) is sufficient to provide a solid laundry detergent article having from 5 wt.% to 30 wt.% of the in-situ formed neutralized salt form of the anionic surfactant, still preferably from 7 wt.% to 25 wt.%, and most preferably from 10 wt.% to 23 wt.% in-situ formed anionic surfactant by weight of the solid laundry detergent article.

[0037] Preferably the amount of acid precursor of anionic surfactant present in step (i) is sufficient to provide a solid laundry detergent bar composition having from 5 wt.% to 30 wt.% of the in-situ formed neutralized salt form of the anionic surfactant, still preferably from 7 wt.% to 25 wt.%, and most preferably from 10 wt.% to 23 wt.% in-situ formed anionic surfactant by weight of the solid laundry detergent bar composition.

[0038] Other suitable anionic surfactant include, soaps, alkyl ether carboxylate. Preferably in the process for preparing the laundry detergent bar composition according to the present invention the liquid acid precursor of anionic surfactant is not a precursor of soap or alkyl ether carboxylate. Preferably in the process for preparing the solid laundry detergent article according to the present invention the liquid acid precursor of anionic surfactant is not a precursor of soap or alkyl ether carboxylate.

[0039] Neutralizing agent

[0040] The acid precursor of anionic surfactant according to the present invention is completely neutralized in-situ to its salt form using a neutralizing agent which is selected from the group consisting of alkali metal carbonate salt, aluminium containing alkaline compound and mixtures thereof. The neutralizing agent according to the present invention is preferably 100% alkali metal carbonate salt.

[0041] Preferred alkali metal carbonate are sodium carbonate, potassium carbonate or mixtures thereof, of which sodium carbonate is particularly preferred. It is further preferred that sodium carbonate makes up at least 75 wt.%, more preferably at least 85 wt.% and even more preferably at least 90 wt.% of the total weight of the alkali metal carbonate salt.

[0042] More preferably the alkali metal carbonate is sodium carbonate in solid form, more preferably light soda ash. Preferably the alkali metal carbonate is synthetically prepared from known process which includes the Solvay process or Hou process. The bulk density of the alkali metal carbonate is preferably from 400 Kg / m3to 800 Kg / m3, still preferably 400 Kg / m3to 800 Kg / m3, more preferably 600 Kg / m3to 800 Kg / m3, still more preferably from 600 Kg / m3to 700 Kg / m3.

[0043] Preferably the alkali metal carbonate salt is in a solid form. Preferably the liquid acid precursor of the anionic surfactant is mixed with the solid alkali metal carbonate. More preferably, the liquid acid precursor of anionic surfactant is sprayed onto the alkali metal carbonate salt in a mixer.

[0044] Preferably the neutralizing agent is an aluminium containing alkaline compound. Preferably the aluminium containing alkaline compound is an alkali metal aluminate. Preferably the alkali metal aluminate has a weight ratio of AI2O3to (Alkali metal^O in a ratio ranging from 0.7 to 1.64, more preferably in a ratio ranging from 0.7 to 0.8. Preferably the neutralizing agent is a mixture sodium carbonate and sodium aluminate. Preferably the amount of neutralizing agent added, preferably where the neutralizing agent is alkali metal carbonate salt, is equal to or in stoichiometric excess to effect complete neutralization of the acid precursor of anionic surfactant. The neutralizing agent selected from alkali metal carbonate salt, aluminium containing alkaline compound and mixtures thereof reacts with the acid precursor of anionic surfactant to form the salt form of anionic surfactant, more preferably the liquid acid precursor of anionic surfactant.

[0045] Preferably, the amount of neutralizing agent with respect to the acid precursor added to the mixing region is at least in stoichiometric equality, most preferably in excess. Preferably, at least 1.25 times required for stoichiometric neutralization is used but preferably no more than 2 times. Higher amounts of alkali metal carbonate salt, for example no more than 5 times, no more than 4.5 times, or no more than 4 times that required for stoichiometric neutralization can be used but these higher amounts are generally less preferred.

[0046] Preferably the solid laundry detergent article prepared by the process according to the first aspect of the present invention includes from 0 wt.% to 3 wt.% neutralizing agent selected from alkali metal carbonate, aluminium containing alkaline compound or mixtures thereof remaining in the solid laundry detergent article after the process. Still preferably the amount of neutralizing agent is from 0 wt.% to 2 wt.%. Still more preferably the solid laundry article includes 0 wt.% neutralizing agent. Most preferably the alkali metal carbonate is sodium carbonate.

[0047] Preferably the laundry detergent bar composition prepared by the process according to the first aspect of the present invention includes from 0 wt.% to 3 wt.% neutralizing agent selected from alkali metal carbonate, aluminium containing alkaline compound or mixtures thereof remaining in the bar after the process. Still preferably the amount of neutralizing agent is from 0 wt.% to 2 wt.%. Still more preferably the laundry detergent bar composition includes 0 wt.% neutralizing agent. Most preferably the alkali metal carbonate is sodium carbonate.

[0048] Step (ii): Forming an aluminium-phosphate complex

[0049] According to the first aspect of the present invention disclosed is a process for preparing a laundry detergent bar composition involving the step (ii) adding phosphorous based acid compound to the solution to adjust the pH ranging from 1 to 5, followed by the addition of an aluminium containing alkaline compound to form a mixture comprising aluminium-phosphate complex and a salt of anionic surfactant. The aluminium-phosphate complex is formed in presence of the neutralized anionic surfactant salt. According to the first aspect of the present invention disclosed is a process for preparing a solid laundry detergent article involving the step (ii) adding phosphorous based acid compound to the solution to adjust the pH ranging from 1 to 5, followed by the addition of an aluminium containing alkaline compound to form a mixture including aluminium-phosphate complex and a salt of anionic surfactant. The aluminium-phosphate complex is formed in presence of the neutralized anionic surfactant salt.

[0050] The aluminium-phosphate complex may preferably be a colloidal complex. Preferably the aluminium-phosphate complex includes a phosphate-based compound, preferably the phosphate-based compound comprises hydrated alkali metal orthophosphate. It is preferred that the colloidal complex has aluminium hydroxide and phosphate-based compound. More preferably the aluminium-phosphate complex comprises hydrated alkali metal orthophosphate and hydrated aluminium. The aluminium-phosphate complex is prepared by reacting aluminium containing alkaline material with a phosphorous-based compound, preferably phosphoric acid. Preferably the laundry detergent bar composition includes a complex of hydrated aluminium oxide and phosphate-based compound. Preferably the laundry detergent bar composition includes a colloidal complex of aluminium hydroxide and phosphate-based compound. More preferably the complex is a mixture of aluminium hydroxide and a phosphate-based compound which is a hydrated alkali metal orthophosphate. Still preferably the aluminium-phosphate complex formed in the process comprises hydrated alkali metal orthophosphate, wherein the hydrated alkali metal orthophosphate is a trisodium orthophosphate octahydrate. Still preferably the complex is a mixture of aluminium hydroxide and trisodium orthophosphate octahydrate.

[0051] Preferably the alkaline material is an alkali metal aluminate. The alkali metal is preferably sodium or potassium, preferably potassium, more preferably sodium. Preferably the alkaline material is sodium aluminate with a solid content ranging from 40 wt.% to 96 wt.%, more preferably solid content ranging from 40 wt.% to 55 wt.%. Preferably the sodium aluminate has a weight ratio of AI2O3to Na2O in a ratio ranging from 0.7 to 1.64, more preferably in a ratio ranging from 0.7 to 0.8.

[0052] Preferably the forming of the colloidal complex of aluminium-phoshpate, more preferably complex of aluminium hydroxide and phosphate-based compound, still preferably where the phosphate compound is hydrated alkali metal orthophosphate involves reacting sodium aluminate having a weight ratio of AI2O3to Na2O in a ratio ranging from 0.7 to 0.8 with phosphorous based acid compound, preferably phosphoric acid at a temperature range of 25°C to 95°C, more preferably temperature range of 65°C to 95°C. It is especially preferable to maintain a weight ratio of AI2O3to based acid compound, preferably phosphoric acid in the range from 0.4 to 2.4, more preferably from 0.4 to 1.56. Commercially available sodium aluminate may be in the form of aqueous solution or solid form. When the sodium aluminate is in an aqueous solution, then the solid content is in the range from 40 wt.% to 55 wt.% and when it is in the solid form it is with a moisture content ranging from 4 wt.% to 35 wt.% having a solid content.

[0053] Aluminium containing alkaline material

[0054] For the purpose of the invention the aluminium containing alkaline material used is alkali metal aluminate which is either in the solid form or a liquid form. More preferably the aluminium containing alkaline material is sodium aluminate solution with a solid content of 40% to 55% or in the solid form where the moisture content of the solid varies between 4% to 35% wherein the AI2O3to Na2O is in a ratio of 0.8 to 1.64.

[0055] Phosphoric acid:

[0056] The commercially available phosphoric acid can be employed in the reaction and the weight ratio of AI2O3to phosphoric acid is preferably 0.4 to 1.56.

[0057] Preferably the detergent bar composition according to the present invention includes from 30 wt.% to 60 wt.% aluminium-phosphate complex. Still preferably the detergent bar composition includes not less than 33 wt.%, still preferably not less than 35 wt.%, still preferably not less than 40 wt.% further preferably not less than 45 wt.% aluminium-phosphate complex by weight of the detergent bar composition. Still preferably the detergent bar composition includes not more than 55 wt.%, still preferably not less than 53 wt.%, still preferably not less than 55 wt.% further preferably not less than 50 wt.% aluminium-phosphate complex by weight of the detergent bar composition.

[0058] Builder

[0059] Preferably the process according to the first aspect of the present invention involves a step of adding a builder before the step of shaping the mixture to form laundry detergent bar composition. Preferably the process according to the first aspect of the present invention involves a step of adding a builder before the step of shaping the mixture to form solid laundry detergent article. Preferably the laundry detergent bar composition includes a builder. The term builder used herein refers to an ingredient which is primarily useful as a means of preventing or ameliorating the adverse effects of calcium and magnesium ions on cleaning, for example by chelation, sequestering, precipitation, or absorption of the ions, and preferably also provides as a source of alkalinity and buffering.

[0060] Preferably the builder is an inorganic builder. Suitable inorganic detergency builders include alkali metal aluminosilicates (zeolites), alkali metal carbonate, alkali metal silicates, and combinations thereof.

[0061] The composition according to the first aspect of the present invention includes 0 wt.% polyphosphate builder and 0 wt.% pyrophosphate builder. Preferably the composition comprises 0 wt.% sodium tripolyphosphate (STPP), 0 wt.% tetrasodium pyrophosphate (TSPP) and mixtures thereof.

[0062] Preferably in the process for preparing the laundry detergent composition according to the present invention, the in-situ formed aluminium-phosphate complex includes an orthophosphate formed when the phosphorous based acid compound, more preferably phosphoric acid reacts with the alkaline aluminate material, the orthophosphate provides for detergency builder. More preferably the in-situ formed orthophosphate is a hydrated alkali metal orthophosphate which provides for detergency builder. The amount of the hydrated alkali metal orthophosphate more preferably alkali metal orthophosphate octahydrate present in the laundry detergent bar composition ranges from 20 wt.% to 35 wt.% by weight of the bar composition, still preferably from 22 wt.% to 35 wt.%.

[0063] Step (iii): Optionally adding a filler to the mixture

[0064] According to the first aspect of the present invention, the next step in the process involves preferably adding a filler which is optional. In a preferred aspect, the process involves the addition of a filler. Preferably the filler may be added at any stage before the shaping of the mixture.

[0065] The filler according to the present invention is preferably selected from the group consisting of aluminosilicate, calcium carbonate, talc, particulate zeolites, calcites, dolomites, feldspar, silica, silicates, kaolin, soapstone, polymeric materials, or mixtures thereof. More preferably the filler is selected from calcite, talc, feldspar, dolomite, or mixtures thereof. Preferably the detergent bar composition according to the present invention includes from 10 wt.% to 40 wt.% filler. Still preferably the detergent bar composition includes not less than 12 wt.%, still preferably not less than 15 wt.%, still preferably not less than 17 wt.% further preferably not less than 20 wt.% filler by weight of the detergent bar composition. Still preferably the detergent bar composition includes not more than 35 wt.%, still preferably not less than 34 wt.%, still preferably not less than 33 wt.% further preferably not less than 30 wt.% filler by weight of the detergent bar composition by weight of the detergent bar composition.

[0066] Step (iv\ Shaping the mixture

[0067] According to the first aspect of the present invention next step involves the step of shaping the mixture to form a solid laundry detergent composition, laundry detergent bar composition.

[0068] According to another aspect of the present invention next step involves the step of shaping the mixture to form a solid laundry detergent article.

[0069] The detergent bar composition of the present invention can be processed in any conventional detergent bar making equipment with some or all of the following key equipment: blender / mixer, mill or refining plodder, two-stage vacuum plodder, logo printer / cutter, cooling tunnel and wrapper.

[0070] In a typical process for preparing the laundry detergent bar composition the raw materials, including the anionic surfactant precursor, preferably non-soap anionic detersive surfactant precursor, are mixed in the blender.

[0071] The process for preparing the laundry detergent bar composition involves a first step of neutralizing the acid precursor of the detersive surfactant, anionic surfactant with a neutralizing agent to form the alkali metal salt of the surfactant. The acid precursor of the anionic surfactant and the neutralizing agent preferably alkali metal carbonate and / or aluminium containing alkaline compound are mechanically worked to effect complete neutralization, preferably for 2 minutes at a temperature ranging from 60°C to 85°C, still preferably from 65°C to 80°C. Preferably the acid precursor of anionic surfactant is linear alkyl benzene sulphonic acid. Preferably the linear alkyl benzene sulphonic acid has 12 to 18 carbon atoms, still preferably alkyl group has 12 to 16 carbon atoms. The linear alkyl benzene sulphonic acid has a purity of 90% or more. The next step involves contacting a phosphorous based acid compound with an alkaline metal aluminate to form a laundry detergent bar composition comprising a complex of aluminium and phosphate. The phosphorous based acid is added to the homogeneous mixture having the in- situ formed anionic surfactant salt and mixed for a period of 3 to 5 minutes to adjust the pH ranging from 1 to 5 and thereafter the aluminium containing alkaline compound preferably the alkaline metal aluminate, still preferably sodium aluminate is added and continuously mixed for around 3 minutes to 5 minutes. Preferably the alkaline metal aluminate is preheated, still preferably the alkaline metal aluminate is maintained at a temperature of 65°C to 85°C and added slowly to the mixture. Preferably before adding the phosphorous based acid compound, optional polymer ingredients for example soil suspending agents and dispersant polymer are added. Preferably the dispersant polymer is a homopolymer of acrylic acid.

[0072] Next step involves adding of the optional filler and builders. The builders have 0 wt.% polyphosphate builder, particularly 0 wt.% STPP. Preferably fillers include feldspar, talc, calcite, and the detergent composition is mixed for a period of 1 to 5 minutes.

[0073] Next further optional ingredients like fragrances, alkaline ingredients, fluorescers, speckles are added and mixed to obtain a homogeneous detergent composition. The detergent composition is thereafter shaped into a detergent bar composition. Preferably the optional ingredient may include a cellulose derivative. Preferably the cellulose derivative is added at any step before shaping the mixture, more preferably wherein the cellulose derivative is selected from the group consisting of hydroxyalkyl alkyl cellulose, cellulose ether and mixtures thereof.

[0074] Typical mixers used in mixing the laundry detergent bar composition include but are not limited to ribbon mixers, sigma-type mixers, soap amalgamators, and plow-type mixers (such as made by Littleford or by Loedige). Such mixers are water-jacketed for temperature control in the mixer, if necessary. The mixing can take from one minute to one hour, with the usual mixing time being from about two to twenty minutes. The mixture from the blender is charged to a surge tank. The mixture preferably is conveyed from the surge tank to the mill or refining plodder via a multi-worm conveyer.

[0075] The step of mechanically working the mixture is carried out preferably in a double vacuum plodder, operating at high vacuum, e.g., 600 to 740 mm of mercury vacuum, so that entrapped air is removed. As used in this description and the claims the term "mechanical working" is intended to describe a device which applies direct shearing action to materials treated by it in order to thoroughly mix the ingredients before they are formed into a bar. Examples of such devices include sigma mixer, roller mills, attrition mills, edge running mills, and multiple plodders with screen plates. This invention does not relate to tablets formed merely by mixing together granular ingredients and forming them into a bar by compressing them within a die or mould.

[0076] The homogenous mixture obtained after mechanically mixing the ingredients is preferably extruded in the step of shaping of the mixture and thereafter preferably cut to the desired bar length and preferably stamped with the product brand name before it is wrapped, cased, and sent to storage.

[0077] Preferably the process involves a step of optionally packaging the laundry detergent bar composition.

[0078] Preferably in the process of preparing the solid laundry detergent article, step (I) and (ii) to form the mixture are similar to the process described herein above. Once the homogeneous mixture is obtained, the step of shaping the mixture to form the solid laundry detergent article can be conducted in any suitable manner, but is not limited to plastifying, extrusion, molding, vacuum forming, coating of a rotating drying surface, pressing, extruding on a continuous belt or screen of a dryer, printing, and coating.

[0079] The process of plastifying to shape the mixture, preferably includes heating the mixture to a temperature of at least 50°C, in particular at least 55°C, still preferably in the rance from 50°C to 100°C, followed by shaping into desired three-dimensional structure and then preferably rapid cooling to a temperature of at most -20°C to form the solid laundry detergent article.

[0080] Preferably the shaped solid laundry detergent article is formed by casting the mixture into a mold or by injection molding the mixture, preferably after the step of plastifying the mixture.

[0081] Preferably the step of casting the mixture involves placing the mixture into shallow cavities or trays or specifically designed mould.

[0082] Solid laundry detergent article

[0083] The term “solid laundry detergent article” refers to a three-dimensional structure, that is it has a thickness, a length, and a width. The three-dimensional shaped body is not substantially flat or planar. The dimensions of the three-dimensional shaped body is such that they have dimensions of at least 1mm, in particular at least 2 mm, in all spatial directions. The dimension is the longitudinal extension of the shaped body in one spatial direction. In case of a sphere, the dimensions are the same for all spatial directions.

[0084] The term "solid" as used herein refers to the ability of an article to substantially retain its shape (i e., without any visible change in its shape) at 20°C and under the atmospheric pressure, when it is not confined and when no external force is applied thereto.

[0085] Preferably the solid laundry detergent article may be any desirable three-dimensional shape, including but not limited to spherical, cubic, rectangular, oblong, cylindrical, rod, sheet, flowershaped, fan shaped, star shaped, disc shaped, and the like.

[0086] Preferably the solid laundry detergent article is a unitary structure which refers to a structure containing a plurality of distinctive parts which are combined together to form a visually coherent and structurally integral article.

[0087] Preferably the shaped laundry detergent article may include further steps of embossing, coating, or printing.

[0088] The solid laundry detergent article may preferably be a unit-dose article. Preferably the article may include an aversive agent such as a bittering agent, preferably at least an outer surface of the article.

[0089] The solid laundry detergent article may preferably be a three-dimensional structure which may be used multiple times.

[0090] The solid laundry detergent article obtainable by the process according to the invention includes an anionic surfactant, an aluminium-phosphate complex, 0 wt.% to 30 wt.% filler and 0 wt.% polyphosphate builder.

[0091] Preferably the solid laundry detergent article according to the present invention includes from 30 wt.% to 60 wt.% aluminium-phosphate complex. Still preferably the solid laundry detergent article includes not less than 33 wt.%, still preferably not less than 35 wt.%, still preferably not less than 40 wt.% further preferably not less than 45 wt.% aluminium-phosphate complex by weight of the solid laundry detergent article. Still preferably the solid laundry detergent article includes not more than 55 wt.%, still preferably not less than 53 wt.%, still preferably not less than 55 wt.% further preferably not less than 50 wt.% aluminium-phosphate complex by weight of the solid laundry detergent article.

[0092] Preferably the builder is an inorganic builder. Suitable inorganic detergency builders include alkali metal aluminosilicates (zeolites), alkali metal carbonate, alkali metal silicates, and combinations thereof.

[0093] The solid laundry detergent article according to an aspect of the present invention includes 0 wt.% polyphosphate builder and 0 wt.% pyrophosphate builder. Preferably the solid laundry detergent article comprises 0 wt.% sodium tripolyphosphate (STPP), 0 wt.% tetrasodium pyrophosphate (TSPP) and mixtures thereof.

[0094] The amount of the hydrated alkali metal orthophosphate, more preferably alkali metal orthophosphate octahydrate present in the solid laundry detergent article ranges from 20 wt.% to 35 wt.% by weight of the solid laundry detergent article, still preferably from 22 wt.% to 35 wt.%.

[0095] Preferably the solid laundry detergent article according to the present invention includes from 10 wt.% to 40 wt.% filler. Still preferably the solid laundry detergent article includes not less than 12 wt.%, still preferably not less than 15 wt.%, still preferably not less than 17 wt.% further preferably not less than 20 wt.% filler by weight of the solid laundry detergent article. Still preferably the solid laundry detergent article includes not more than 35 wt.%, still preferably not less than 34 wt.%, still preferably not less than 33 wt.% further preferably not less than 30 wt.% filler by weight of the solid laundry detergent article.

[0096] The laundry detergent bar composition is preferably a preferred embodiment of the solid laundry detergent article.

[0097] The description for the laundry detergent bar composition provided hereinbelow also applies to the solid laundry detergent article.

[0098] The solid laundry detergent article includes an anionic surfactant as described herein below. The solid laundry detergent article may preferably include one or more of the non-ionic detersive surfactant, cationic detersive surfactant, amphoteric surfactant, zwitterionic surfactant as described herein below.

[0099] The solid laundry detergent article may preferably include one or more of the filler, builder particulate structurants, optional ingredients, structuring agent, cellulose derivative as described herein below.

[0100] The solid laundry detergent article may preferably have a moisture content as described herein below.

[0101] Laundry detergent bar composition

[0102] According to a second aspect of the present invention disclosed is a laundry detergent bar composition obtainable by a process according to the first aspect of the present invention.

[0103] The laundry detergent composition obtainable by the process according to the invention includes an anionic surfactant, an aluminium-phosphate complex, 0 wt.% to 30 wt.% filler and 0 wt.% polyphosphate builder.

[0104] Preferably the laundry detergent bar composition has a penetration value of less than 10, still preferably less than 5, further preferably less than 3. The penetration value is measured using a method as described herein below in the Examples herein below.

[0105] Anionic surfactant:

[0106] The laundry detergent bar composition according to the present invention includes an anionic surfactant. Preferably the anionic surfactant is a non-soap anionic detersive surfactant. As used herein “non-soap anionic detersive surfactant” refers to a surfactant other than the following: alkali (e.g., Na+and K+), alkaline earth (e.g., Mg2+and Ca2+), ammonium, or triethanolamine salts of saturated and unsaturated C6 to C24 fatty acids, i.e. , alkyl monocarboxylate salts. As one skilled in the art will recognize, soaps are most often derived from the saponification of triglycerides.

[0107] Suitable examples of detersive surfactant material are compounds commonly used as surfaceactive agents given in the well-known textbooks: "Surface Active Agents" Vol. 1 , by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958; in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company; or in "Tenside-Taschenbuch", H. Stache, 2ndEdn., Carl Hauser Verlag, 1981.

[0108] As used herein “anionic surfactant” refers to an amphiphilic molecule comprising a hydrophobic group and one or more hydrophilic groups comprising a negatively charged moiety or a moiety capable of bearing a negative charge (in the latter case, for example, as a function of acid-base properties and solution pH).

[0109] Non-soap anionic detersive surfactant which are suitable for use in a detergent bar composition according to the present invention include the water-soluble salts, preferably the alkali metal, ammonium and alkylammonium salts of organic sulfuric reaction products having in their molecular structure an alkyl group containing from 10 to 22 carbon atoms and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl groups.) Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8to 18 carbon atoms); and the sodium and potassium alkylbenzene sulfonates in which the alkyl group contains from about 9 to 22 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U.S. Patents 2,220,099 and 2,477,383. Especially valuable sulfonates are linear straight chain alkylbenzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 11 to 13, abbreviated as C11 to 13 LAS. The alkali metal salts, particularly the sodium salts of these surfactants are preferred.

[0110] Other suitable anionic surfactants are the sodium alkyl glyceryl ether sulfonates, especially ethers of higher alcohols; sodium C8to 18 fatty acid monoglyceride sulfonates and sulfates; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl group contains from about 10 to about 20 carbon atoms.

[0111] In addition, suitable anionic surfactants include the water-soluble salts of esters of alpha- sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1- sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; water-soluble salts of olefin and paraffin sulfonates containing from about 12 to 20 carbon atoms; and beta-alkyloxy alkane sulfonates containing from about 1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms in the alkane moiety. Preferably the anionic surfactant is a non-soap anionic surfactant. Preferably the anionic surfactant is not a salt of fatty acids or fat having an iodine value in the range from 0 to 100.

[0112] Preferred anionic surfactants include C10- 18 alkyl sulfates, C10-22 alkylbenzene sulfonates and mixtures thereof. Most suitably the anionic detersive surfactant is LAS.

[0113] Preferably the laundry bar composition includes from 5 wt.% to 30 wt.% anionic surfactant, more preferably from 7 wt.% to 25 wt.% anionic surfactant, still more preferably from 10 wt.% to 23 wt.% anionic surfactant. Still preferably the detergent bar composition includes not less than 7 wt.%, still preferably not less than 10 wt.%, still preferably not less than 15 wt.% further preferably not less than 18 wt.% anionic surfactant by weight of the detergent bar composition. Still preferably the detergent bar composition includes not more than 28 wt.%, still preferably not less than 25 wt.%, still preferably not less than 23 wt.% further preferably not less than 22 wt.% anionic surfactant by weight of the detergent bar composition by weight of the detergent bar composition.

[0114] Preferably 100% of the anionic surfactant present in the laundry detergent bar composition is formed in-situ. Preferably the anionic surfactant is a non-soap anionic surfactant. Non-limiting examples includes sulphonate surfactant, sulfate surfactant or mixtures thereof. A particularly preferred sulphonate surfactant is an alkyl benzene sulphate surfactant, still preferably linear alkyl benzene sulphonate surfactant.

[0115] Preferably the amount of anionic soap based detersive surfactant in the laundry detergent bar composition according to the present invention is from 0 to 10 wt.%, still preferably from 0 to 5 wt.% and further preferably from 0 to 3 wt.% and most preferably from 0 to 1 wt.% based on the weight of the laundry detergent bar composition. The term “soap” is used herein in its popular sense, i.e. , the alkali metal or alkanol ammonium salts of aliphatic, alkane or alkene monocarboxylic acids. The soap may be from any of the triglycerides conventionally used in soap manufacture. Preferably the carboxylate anion in the soap may contain from 8 to 22 carbon atoms, more preferably from 12 to 18 carbon atom fatty acids. The alkali metal or alkanol ammonium salt being preferably selected from sodium, potassium, magnesium, mono-, di- and tri-ethanol ammonium cations, or combinations thereof. In addition to the anionic surfactant, the detergent bar composition according to the present invention, preferably includes additional detersive surfactants including but not limited to nonionic, cationic, amphoteric zwitterionic surfactant or mixtures thereof.

[0116] Non-ionic detersive surfactant:

[0117] Preferably the detergent bar composition includes a non-ionic detersive surfactant. Typical nonionic detersive surfactants include the alkylene oxide condensates of hydrocarbyl groups. Preferably the hydrocarbyl group is aliphatic or alkyl aromatic. Preferably the hydrocarbyl group is an alkyl group, alkyl phenyl group or mixtures thereof. The hydrocarbyl group preferably includes from 8 to 22 carbon atoms.

[0118] Particular examples include the condensation product of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a coconut oil ethylene oxide condensate having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group contains from 6 to 12 carbon atoms with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40% to 80% of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11 ,000; tertiary amine oxides of structure R3NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance dimethyl dodecyl amine oxide; tertiary phosphine oxides of structure R3PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide; and dialkyl sulphoxides of structure R2SO where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans.

[0119] Also preferred are non-ionic surfactant which have semi polar compounds such as Cs to C22amine oxides. Preferably non-ionic surfactant of the fatty acid amide surfactants type represented by the general formula: wherein: Ri is H, C1 to Cs hydrocarbyl, 2-hydroxyethyl, 2-hydroxypropyl, or a mixture thereof, preferably C1 to C4 alkyl, more preferably C1 to C2 alkyl, most preferably C1 alkyl (i.e., methyl); and R2 is a C5 to C32 hydrocarbyl moiety, preferably straight chain C7 to C19 alkyl or alkenyl, more preferably straight chain C9 to C17 alkyl or alkenyl, most preferably straight chain C11 to C19 alkyl or alkenyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 2 (in the case of glyceraldehyde) or at least 3 hydroxyls (in the case of other reducing sugars) directly connected to the chain or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof.

[0120] Z preferably will be selected from the group consisting of -CH2-(CHOH)n-CH2-OH, -CH(-CH2-OH)-(CHOH)n-1-CH2-OH, -CH2(CHOH)2(CHOR’)(CHOH)-CH2-OH, where n is an integer from 1 to 5, inclusive, and R’ is H or a cyclic mono- or poly- saccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4, particularly -CH2-(CHOH)4CH2- OH.

[0121] In the above formulas, R1 can be, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 2- hydroxy ethyl, or 2-hydroxy propyl. For highest sudsing, R1 is preferably methyl or hydroxyalkyl. If low sudsing is desired, R1 is preferably C2-C8alkyl, especially n-propyl, iso-propyl, n-propyl, iso-propyl, n-butyl, iso-butyl, pentyl, hexyl and 2-ethyl hexyl.

[0122] Specific examples of this type of non-ionic amide surfactant include Ci2-N-(3methyxypropyl) glucamide and C12 n-methyl glucamide.

[0123] Cationic detersive surfactant:

[0124] The detergent bar composition may preferably include a cationic detersive surfactant. Cationic detersive surfactant include the ammonium surfactant such as alkyl dimethylammonium halides, and those surfactants having the formula: [R2(OR3)y[R4(OR3)y]2R5N+X- wherein R2is an alkyl or alkyl benzyl group having from about 8 to about 18 carbon atoms in the alkyl chain, each R3is selected from the group consisting of -CH2CH2-, -CH2CH(CH3)-, -CH2CH(CH2OH)-, - CH2CH2CH2-, and mixtures thereof; each R4is selected from the group consisting of C1-C4 alkyl, C1-C4 hydroxyalkyl, benzyl, ring structures formed by joining the two R4groups, CH2CHOHCHOHCOR6CHOHCH2OH wherein R6 is any hexose or hexose polymer having a molecular weight less than about 1000, and hydrogen when y is not 0; R5is the same as R4or is an alkyl chain wherein the total number of carbon atoms of R2plus R5is not more than about 18; each y is from 0 to about 10 and the sum of the y values is from 0 to about 15; and X is any compatible anion.

[0125] Suitable cationic surfactant that can be incorporated are alkyl substituted quarternary ammonium halide salts e.g., bis (hydrogenated tallow) dimehtylammonium chlorides, cetyltrimethyl ammonium bromide, benzalkonium chlorides and dodecylmethylpolyoxyehtylene ammonium chloride and amine and imidazoline salts for e.g., primary, secondary, and tertiary amine hydrochlorides and imidazoline hydrochlorides.

[0126] Amphoteric surfactant:

[0127] The detergent bar composition according to the present invention may preferably include an amphoteric detersive surfactant. Amphoteric surfactants can be broadly described as aliphatic derivatives of secondary or tertiary amines, or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched. One of the aliphatic substituents contains at least 8 carbon atoms, typically from 8 to 18 carbon atoms, and at least one contains an anionic water-solubilizing group, e.g., carboxy, sulfonate, sulfate.

[0128] Suitable amphoteric detersive surfactant that optionally can be employed are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance sodium 3- dodecylamino- propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2- hydroxydodecyl-N-methyltaurate.

[0129] Zwitterionic surfactant:

[0130] The detergent bar composition according to the present invention may preferably include a zwitterionic detersive surfactant. Zwitterionic surfactants can be broadly described as derivatives of secondary and tertiary amines, derivatives of heterocyclic secondary and tertiary amines, or derivatives of quaternary ammonium, quaternary phosphonium or tertiary sulfonium compounds.

[0131] Suitable zwitterionic detersive surfactant that optionally can be employed are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic watersolubilising group, for instance 3-(N-N-dimethyl-N-hexadecylammonium) propane-1- sulphonate betaine, 3-(dodecylmethyl sulphonium) propane-1 -sulphonate betaine and 3-(cetylmethyl phosphonium) ethane sulphonate betaine.

[0132] Preferably the detergent bar composition according to the present invention includes a combination of anionic surfactant with one or more of the additional surfactant selected from the group consisting of non-ionic surfactant, amphoteric surfactant, cationic surfactant and zwitterionic surfactant. Preferably anionic surfactant is present in amount of at least 50 parts of by weight of the total detersive surfactant content in the detergent bar composition. Still preferably at least 60 parts, still preferably at least 70 parts, still more from 50 parts to 100 parts by weight of the total detersive surfactant content in the detergent bar composition is anionic surfactant, more preferably the anionic non-soap surfactant.

[0133] Filler:

[0134] The laundry detergent bar composition preferably includes a filler. The term “ filler” as used herein and as applied to detergent composition, refers to any compatible inert substance employed as a diluent in detergent bar composition to facilitate the adjustment of the proportions of the other components to desired levels.

[0135] Suitable filler is an inorganic particulate material. More preferably the filler is selected from the group consisting of zeolite, calcite, dolomite, aluminium silicate minerals, feldspar, silica, silicate, carbonate salt, bicarbonate salt, borate salt, hydrous magnesium silicate (talc), sulphate salt and polymeric materials. The polymeric material may be preferably polyethylene.

[0136] More preferred the inorganic particulate material is selected from the group consisting of calcium carbonate (as Calcite), mixtures of calcium and magnesium carbonate (as dolomite), sodium hydrogen carbonate, sodium / potassium sulphate, sodium / potassium chloride, zeolite, feldspars, talc, kaolin, silica, and soapstone.

[0137] Calcite, talc, kaolin, feldspar and dolomite and mixtures thereof are particularly preferred due to their low cost and colour. Preferably the laundry detergent bar composition according to the present invention includes aluminium silicates, preferably feldspar, calcium silicate, hydrous magnesium silicate or mixtures thereof. Most preferably the filler is selected from calcite, talc, aluminosilicate, and mixtures thereof. Preferably the filler is selected from the group consisting of aluminium silicates, preferably feldspar, calcium silicate, hydrous magnesium silicate or mixtures thereof. Preferably the detergent bar composition according to the present invention includes from 10 wt.% to 40 wt.% filler. Still preferably the detergent bar composition includes not less than 12 wt.%, still preferably not less than 15 wt.%, still preferably not less than 17 wt.% further preferably not less than 20 wt.% filler by weight of the detergent bar composition. Still preferably the detergent bar composition includes not more than 35 wt.%, still preferably not less than 34 wt.%, still preferably not less than 33 wt.% further preferably not less than 30 wt.% filler by weight of the detergent bar composition by weight of the detergent bar composition.

[0138] Builder:

[0139] Preferably the laundry detergent composition includes an organic builder. Suitable organic detergency builders include citrates, sodium nitrilotriacetate (NTA) various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxy sulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetra acetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, and citric acid.

[0140] Polymeric polycarboxylate builders are also useful. Such materials include the water-soluble salts of homo- and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylene malonic acid. More preferably the polycarboxylate builders includes sodium citrate, sodium tartrate, sodium mono- and di- succinates and mixtures thereof.

[0141] Preferably the laundry detergent bar composition according to the present invention includes has a total content of builder from 4 wt.% to 50 wt.%. Preferably the laundry detergent bar composition comprises at least 6 wt.% builder, still preferably at least 8 wt.%, still preferably at least 15 wt.%, most preferably at least 20 wt.%, but typically not more than 48 wt.%, still preferably not more than 45 wt.%, most preferably not more than 40 wt.%. Preferably the builder includes sodium carbonate, alkaline sodium silicate, mixtures thereof.

[0142] Particulate structurants

[0143] Optionally the laundry detergent bar composition may include a particulate structurant. Nonlimiting examples of the particulate structurants include aluminosilicate which may preferably be generated in-situ by reacting aluminium sulphate and sodium silicate. It is also possible to incorporate preformed particulate structurants which includes but is not limited to alkali metal aluminosilicate, aluminium sulphate, magnesium sulphate, aluminium hydrate, alkaline silicate, calcium hydroxide and mixtures thereof.

[0144] Optional ingredients

[0145] The minor and conventional optional ingredients are preferably selected from colour, enzymes, antiredeposition agents, fluorescers, preservatives and perfumes, also bleaches, bleach precursors, bleach stabilizers, sequestrants, soil release agents (usually polymers) and other polymers, polysaccharides such as starch or modified starches may optionally be incorporated up to 10 wt.% by weight of the laundry detergent bar composition.

[0146] Chelant:

[0147] A particularly preferred optional ingredient for laundry detergent bar composition according to the present invention is a chelant. Such chelants can sequester and chelate alkali cations (such as sodium, lithium, and potassium), alkali metal earth cations (such as magnesium and calcium), and most importantly, heavy metal cations such as iron manganese, zinc, and aluminum. Preferred cations include sodium, magnesium, zinc, and mixtures thereof. The chelant is particularly beneficial for maintaining good cleaning performance and improved surfactant mileage, despite the presence of the softening clay and the clay flocculating agent.

[0148] The chelant is preferably a phosphonate chelant, particularly one selected from the group consisting of diethyienetriamine penta(methylene phosphonic acid), ethylene diamine tetra(methylene phosphonic acid), and mixtures and salts and complexes thereof, and an acetate chelant, particularly one selected from the group consisting of diethyienetriamine penta(acetic acid), ethylene diamine tetra(acetic acid), and mixtures and salts and complexes thereof. Particularly preferred are sodium, zinc, magnesium, and aluminum salts and complexes of diethyienetriamine penta(methylene phosphonate) diethyienetriamine penta (acetate), and mixtures thereof.

[0149] The chelant can be included in laundry detergent bar composition at a level up to about 5wt%, preferably from about 0.1 wt% to about 3wt%, more preferably from about 0.2wt% to about 2wt%, most preferably from about 0.5wt% to about 1.0wt%. Bleach:

[0150] Yet another optional component in laundry detergent bar composition is a bleach component. The bleaching component can be a source of -OOH group, such as sodium perborate monohydrate, sodium perborate tetrahydrate and sodium percarbonate. Sodium percarbonate (2Na2CO3-3H202) is preferred since it has a dual function of both a source of HOOH and a source of sodium carbonate. Another optional bleaching component is a peracid, such as a formula: CH3(CH2)w-NH-C(O)-(CH2)zCO3H wherein z is from 2 to 4 and w is from 4 to 10. The bleaching component can contain, as a bleaching component stabilizer, a chelating agent of polyaminocarboxylic acids, polyaminocarboxylates such as ethylenediaminotetraacetic acid, diethylenetriaminopentaacetic acid, and ethylenediaminodisuccinic acid, and their salts with water-soluble alkali metals.

[0151] The bleach components can be added to the laundry detergent bar composition at a level up to 20 wt.%, preferably from 1 wt.% to 10 wt.%, more preferably from 2 wt.% to 6 wt.%.

[0152] Binding agents:

[0153] Binding agents for holding the detergent bar composition together in a cohesive, soluble form can also be used, and include natural and synthetic starches, gums, thickeners, and mixtures thereof.

[0154] Soil suspending agents:

[0155] Soil suspending agents can be used in laundry detergent bar composition. Soil suspending agents includes water-soluble salts of carboxymethylcellulose and carboxyhydroxymethylcellulose. A preferred soil suspending agent is an acrylic / maleic copolymer, commercially available under the tradename as Sokolan™, from BASF Corp. Other soil suspending agents include polyethylene glycols having a molecular weight of about 400 to 10,000, and ethoxylated mono- and polyamines, and quaternary salts thereof.

[0156] Dispersant polymer:

[0157] Optionally the laundry detergent bar composition includes a dispersant polymer. Preferably the dispersant polymer is an anionic polymer. Preferably the dispersant polymer is polyacrylic acid. Preferably a homopolymer of acrylic acid. Preferably the homopolymer of acrylic acid has a weight average molecular weight (Mw) ranging from 1000 g / mole to 10000 g / mole, still preferably 1000 g / mole to 3000 g / mole. Preferably the homopolymer of acrylic acid has a weight average molecular weight (Mw) of at least 1500 g / mole, preferably at least 2000 g / mole but preferably nor more than 10000 g / mole, still preferably not more than 8000 g / mole, still more preferably not more than 6000 g / mole, furthermore preferably not more than 3000 g / mole. Preferably, the laundry detergent bar comprises at least 0.2 wt.% of the polyacrylic acid, preferably at least 0.4 wt.%, preferably at least 0.6 wt.; preferably no more than 4.5 wt.%, preferably no more than 4 wt.%, preferably no more than 3.5 wt.%, preferably no more than 3 wt.%.

[0158] Optical brighteners:

[0159] Optical brighteners are also preferred optional ingredients in detergent bar composition. Preferred optical brighteners are diamino stilbene, distyrilbiphenyl-type optical brighteners. Preferred as examples of such brighteners are 4,4’-bis([4-anilino-6bis(2-hydoxyethyl) amino-1 1,3,5-trizin-2-yl]amino}stilbene-2,2’-disulfonic acid disodium salt, 4-4’-bis(2-sulfostyryl) biphenyl and 4,4’-bis[(4-anilino-6morpholino-1 ,3,5-triazin-2-yl) amino]stilbene-2,2’-disulfonic acid disodium salt.

[0160] Such optical brighteners, or mixtures thereof, can be used at levels in the range from 0.05 wt.% to 1.0 wt.% bar in the laundry detergent bar composition.

[0161] In addition to the above-described optional ingredients, the laundry detergent bar composition may also preferably include ingredients such as solvents, amines, perfumes, coloring agents, fluorescers, coloured speckles, buffers, alkaline ingredients can also be used in the formulation, for example, in an amount up to 10 wt%.

[0162] Structuring agent:

[0163] The laundry detergent bar composition according to the present invention may preferably include further structuring agent. The term “structuring agent” as used herein refers to a material or mixture of materials which is capable of retaining high amounts of moisture and when added to a detergent bar composition the structuring agent enables the bar to retain high levels of moisture without compromising on the bar properties.

[0164] The further structuring agent suitable for the present invention includes those known in the art to retain high levels of moisture and includes but is not limited to colloidal aluminium hydroxide, aluminium hydroxide-sulphate complex, alumina gel, amorphous silica, hydrated alkali metal carbonate material, hydrated aluminium material, hydrated silica material, silica or mixtures thereof. Preferably the structuring agent is formed in-situ. Moisture content:

[0165] The laundry detergent composition according to the first aspect or second aspect may preferably include from 15 wt.% to 32 wt.% total moisture content. This moisture content includes both the bound and the unbound water. The total moisture content of the laundry detergent composition is determined by hot air oven method where approximately 10 grams of bar sample is heated at 135°C in a fan-assisted oven until no further weight loss occurs for a duration of 3 to 4 hours. The moisture content is calculated using below equation:

[0166] Where,

[0167] W1 = Weight (g) of sample

[0168] W2 = Weight (g) of dried sample

[0169] Cellulose derivative:

[0170] Preferably the laundry detergent bar composition includes a cellulose derivative, more preferably a non-ionic cellulose derivative. Preferably the cellulose derivative is a nonionic cellulose derivative, still preferably a nonionic cellulose ether. Preferably the cellulose derivative is multifunctional.

[0171] More preferably the cellulose derivative is selected from the group consisting of hydroxyalkyl alkyl cellulose and derivatives thereof. More preferably the cellulose derivative is selected from the group consisting of hydroxyalkyl alkyl cellulose. Preferably a hydroxy-(C1-4) alkyl CM alkyl cellulose. Preferably, the hydroxyalkyl groups has from 1 to 4 carbon atoms preferably from 1 to 3 carbon atoms; more preferably from 2 to 3 carbon atoms; most preferably 2 carbon atoms. Preferably the alkyl groups have from 1 to 4 carbon atoms, preferably from 1 to 3 carbon atoms; more preferably from 1 to 2 carbon atoms; most preferably 1 carbon atom. Non-limiting examples includes a hydroxyalkyl methylcellulose, preferably selected from the group consisting of hydroxyethyl methyl cellulose, hydroxypropyl methylcellulose and mixtures thereof. Still more preferably the hydroxyalkyl alkyl cellulose is selected a hydroxyethyl methyl cellulose.

[0172] Preferably the cellulose derivative is a hydroxyalkyl alkyl cellulose having a weight average molecular weight (Mw) ranging from 25,000 to 4,000,000 Daltons preferably from 25,000 to 1,500,000 Daltons; more preferably from 25,000 to 500,000 Daltons; most preferably from 25,000 to 150,000 Daltons. Preferably the cellulose derivative is a hydroxyalkyl alkyl cellulose wherein the hydroxyalkyl alkyl cellulose is a cellulose ether having alkyl and hydroxyalkyl derivatives in which the average number of substituent groups per anhydroglucose unit is from 1 to 3, preferably from 1.5 to 3 still more preferably from 2 to 3. Preferably, the hydroxyalkyl groups have from 1 to 4 carbon atoms preferably from 1 to 3 carbon atoms; more preferably from 2 to 3 carbon atoms; most preferably 2 carbon atoms. Preferably, the alkyl groups have from 1 to 4 carbon atoms preferably from 1 to 3 carbon atoms; more preferably from 1 to 2 carbon atoms; most preferablyl carbon atom.

[0173] Preferably the cellulose derivative is selected from the group consisting of a hydroxyalkyl alkyl cellulose; wherein the hydroxyalkyl alkyl cellulose has a substantially linear cellulose backbone. The term “substantially linear” as used herein means that 97 wt.% to 100 wt.% of the glucose units in the hydroxyalkyl alkyl cellulose are in a main chain of the cellulose backbone, still more preferably 99 wt.% to 100 wt.% of the glucose units are in a main chain of the cellulose backbone.

[0174] Preferably the hydroxyalkyl alkyl cellulose has a substantially p-1 ,4 linked backbone. The term “substantially β -1,4 linked backbone” as used herein means that from 97 wt.% to 100 wt.%, preferably from 99 wt.% to 100 wt.% of the glucose units in the hydroxyalkyl alkyl cellulose are bounded together with p -1,4 linkages. When less than 100 wt% of the glucose units are bounded together with p -1,4 linkages, the remaining glucose units may be bounded in a variety of ways, including, for example, P-1,2; P-1,3; P-1,6; P-2,3; a-1,2; a-1,3; a-1,4; a-1,6 and a-2,3 linkages and mixtures thereof.

[0175] Preferably the cellulose derivative has a viscosity ranging from 7400 mPa.s to 16000 mPa.s, more preferably from 12000 mPa.s to 16000 mPa.s when measured using a 1% solution in water with a Haake Rotovisko RV 100 having a shear rate 2.55 s-1and at 20°C.

[0176] Preferably the laundry detergent bar composition according to the present invention comprises from 0.01 wt.% to 5 wt.% cellulose derivative, still preferably 0.01 wt.% to 1.5 wt.%, still more preferably from 0.1 wt.% to 1.5 wt.% cellulose derivative. Preferably the laundry detergent bar composition comprises at least 0.05 wt.% cellulose derivative, still preferably at least 0.08 wt.%, still preferably at least 0.1 wt.%, most preferably at least 0.2 wt.%, but typically not more than 4 wt.%, still preferably not more than 3 wt.%, most preferably not more than 1.5 wt.%. The invention may be further understood by reference to the examples hereinafter which are not to be construed as limiting the scope of the present invention.

[0177] Preferably the laundry detergent bar composition obtainable according to the first aspect of the invention comprises a clay-based speckle.

[0178] Preferably the solid laundry detergent article obtainable according to the first aspect of the invention comprises a clay-based speckle.

[0179] Examples

[0180] Example 1 : A process for preparing a detergent bar composition according to the present invention to obtain a laundry detergent bar composition as provided in table 1 was carried out as follows:

[0181] In the first step a Na salt of LAS anionic surfactant was prepared by reacting the precursor, LAS acid with sodium carbonate in a sigma mixture which was maintained at a temperature 75°C and mixing until the LAS acid was completely neutralized to form sodium linear alkyl benzene sulphonate. Thereafter 85% purity phosphoric acid was added to adjust the pH. Next an aqueous solution of sodium aluminate having a solid content of 40 wt.% and a AI2O3to Na2O in a ratio of 0.7 was added to the above mixture and mixed for about 6 minutes to form colloidal aluminium-phosphate complex. The colloidal complex is a mixture of trisodium orthophosphate octahydrate and hydrated aluminium hydroxide. Next fillers (feldspar, calcium carbonate and talc were added) and alkaline ingredient (sodium silicate) was added and mixed to form a dough. The mixture was next extruded to form the laundry detergent bar composition.

[0182] The prepared bar composition was evaluated for various properties as provided in the table 1 below.

[0183] Measurement method

[0184] Penetration value: Penetration value indicating the hardness of the bar was measured using a cone penetrometer the details of a typical instrument and the method of measurement is given below.

[0185] Cone type Penetrometer

[0186] MANUFACTURER: Adair Dutt & Company, Bombay. RANGE OF MEASUREMENT: 0-40 mm

[0187] RANGE OF VERIFICATION: 20 in steps of 5

[0188] Procedure of Measurement: Let the entire mass (comprises of penetrometer needle and standard weight) which just rests on the test sample, drop freely and thus penetrate the test mass to a specific distance for a specified period of time and read of this distance as 1 / 10thof mm. Take the average after repeating the exercise for at least 3 times.

[0189] Density of the bar:_The density of the bar is measured by the standard method and calculated using the formula

[0190] Density (grams / cm3) = Weight of bar (grams) / Volume in cm3

[0191] Lather: Refers to foam generated during wash by which the consumer controls the product dosage.

[0192] Table 1 - Composition of the prepared laundry detergent bar composition

[0193] The data in table 1 shows that a composition having 0 wt.% STPP and having an aluminium phosphate complex provides a detergent bar composition which has good physical properties and gives good lather and sensorial properties.

[0194] Example 2: Evaluation of the properties of detergent bar prepared by two different process steps: Comparative detergent bar and a detergent bar according to the present invention were prepared using the process as described herein below.

[0195] Ex A: The comparative laundry detergent bar with a composition as shown in table 2, was prepared by adding acid precursor of LAS and sodium aluminate having a solid content of 40 wt.% and a AI2O3to Na2O in a ratio of 0.7 in a sigma mixer and mixed together. Thereafter 85% purity phosphoric acid was added to the above mixture and mixed for about 6 minutes to form colloidal aluminium-phosphate complex. Next fillers and structurants (feldspar, calcium hydroxide (structurant) and talc) were added and alkaline ingredient (sodium silicate) was added and mixed to form a mixture. The mixture was next extruded to form the laundry detergent bar composition.

[0196] Ex 2: The inventive laundry detergent bar with a composition as shown in table 2, was prepared as follows. In the first step a Na salt of LAS anionic surfactant was prepared by reacting the precursor, LAS acid with sodium aluminate in a sigma mixture which was maintained at a temperature 75°C and mixing until the LAS acid was completely neutralized to form sodium linear alkyl benzene sulphonate. Thereafter 85% purity phosphoric acid was added to adjust the pH ranging from 1 to 5. Next an aqueous solution of sodium aluminate having a solid content of 40 wt.% and a AI2O3to Na2O in a ratio of 0.7 was added to the above mixture and mixed for about 6 minutes to form colloidal aluminium-phosphate complex. The colloidal complex was a mixture of trisodium orthophosphate octahydrate and hydrated aluminium hydroxide. Next fillers and structurant (feldspar, calcium hydroxide and talc) were added and alkaline ingredient (sodium silicate) was added and mixed to form a mixture. The mixture was next extruded to form the laundry detergent bar composition.

[0197] The prepared laundry detergent bar composition was evaluated for various properties and were recorded. The results are provided in the table 2 below.

[0198] Table 2

[0199] The data provided in table 2 clearly shows that the laundry detergent bar composition prepared by the process according to the present invention (Ex 2) has improved properties as compared to the comparative detergent composition (Ex A). The inventive laundry detergent bar is significantly better in bar hardness and the rate of wear resulting from the change in the process parameters.

Claims

AMENDED CLAIMS received by the International Bureau on 30 October 2024 (30.10.2024)CLAIMS1. A process for preparing a solid laundry detergent article comprising:(i) an anionic surfactant;(ii) an aluminium-phosphate complex;(iii) 0 wt.% to 30 wt.% filler; and,(iv) 0 wt.% polyphosphate builder. wherein the process comprises the steps of:(i) admixing in any order an acid precursor of anionic surfactant and a neutralizing agent selected from the group consisting of an alkali metal carbonate, aluminium containing alkaline compound or mixture thereof to effect complete neutralization of the acid precursor of anionic surfactant to form an anionic surfactant salt;(ii) adding phosphorous based acid compound to the solution to adjust the pH ranging from 1 to 5, followed by the addition of aluminium containing alkaline compound to form a mixture having aluminium-phosphate complex and anionic surfactant salt;(iii) optionally adding a filler;(iv) shaping the mixture to form a solid laundry detergent article.

2. A process according to claim 1 wherein the aluminium-phosphate complex comprises a hydrated alkali metal orthophosphate, preferably a mixture of hydrated aluminium oxide and hydrated alkali metal orthophosphate.

3. A process according to claim 2 wherein the hydrated alkali metal orthophosphate is a trisodium orthophosphate octahydrate.

4. A process according to claim 1 wherein the phosphorous based acid compound is phosphoric acid.

5. A process according to claim 1 wherein the aluminium containing alkaline compound is an alkali metal aluminate.

6. A process according to any one of the preceding claims wherein the alkali metal aluminate has a weight ratio of AI2O3to (Alkali metal)2O in a ratio ranging from 0.7 to 1 .64, more preferably in a ratio ranging from 0.7 to 0.8.

7. A process according to any one of the preceding claims wherein the weight ratio of alumina AI2O3to phosphorous based acid compound ranges from 0.4 to 1.56.

8. A process according to any one of the preceding claims comprising the step of adding of a cellulose derivative at any step before shaping the mixture, preferably wherein the cellulose derivative is selected from the group consisting of hydroxyalkyl alkyl cellulose, cellulose ether, and mixtures thereof.

9. A process according to any one of the preceding claims wherein the hydrated alkali metal orthophosphate is present in an amount ranging from 20 wt.% to 35 wt.% by weight of the bar composition or by weight of the solid laundry detergent article.

10. A process according to any one of the preceding claims wherein the laundry detergent bar composition or the solid laundry detergent article comprises a total moisture content which ranges from 15 wt.% to 32 wt.%.

11. A process according to any one of the preceding claims comprising the step of adding a perfume at any step before shaping the mixture, preferably wherein the perfume is selected from the group consisting of fragrance oil, encapsulated perfume, or mixtures thereof.

12. A solid laundry detergent article obtainable according to any one of the preceding claims 1 to 11.

13. A solid laundry detergent article according to claim 12 comprising a builder selected from the group consisting of alkali metal carbonate, alkali metal silicate, polycarboxylates or mixtures thereof.

14. A solid laundry detergent article according to claim 12 comprising an antiredeposition / dispersant polymer, preferably wherein the antiredeposition / dispersant polymer is a homopolymer of acrylic acid.

15. A solid laundry detergent article according to any one of the preceding claims 12 to 14 wherein the solid laundry detergent article is a laundry detergent bar composition.

Images