CZ20031054A3 - Washing detergent - Google Patents

Abstract

Flux-proof detergent that retains rigidity at least 40 ° C and includes: (a) 2 to 50 (Xj% % by weight of a saturated fatty acid soap comprising one or more of a C 6 -C 24 fatty acid salt; (b) 2 to 40 % by weight of detergent-active agents; (c) 0.5 to 20% the weight of the salting-out electrolyte; and (d) 30 to 80% water weight; wherein the fatty acid soap is present forming an Xa% solution in liquid phase water with a viscosity less than 50 Pa.s at a shear rate of 1 / s over a temperature range of 50 up to 100 ° C, shows phase separation, presence of solid phase during cooling down to 20 ° C and said solid phase is during CO was heated to at least 40 ° C. Another solution is a method of manufacturing the above product.

Description

Detergent

Technical field

The present invention relates to the provision of a suitable type and combination of a fatty acid or fatty acids to form a soap for obtaining solid melt casting formulations containing very high levels of water or liquid benefit agents.

BACKGROUND OF THE INVENTION

Detergent tablets are commonly produced by one of two methods: (i) slicing / homogenizing the product followed by extrusion and stamping, or (ii) casting.

In the manufacture of carve bars by slicing and extrusion, the amount of water that can be incorporated into the composition is typically less than about 15%. These systems are multiphase mixtures (composites) that exhibit morphology of the type of bricks suspended in mortar. Bricks are solid particles which in the case of toilet soaps are crystalline salts of long-chain saturated fatty acids, inorganic fillers and the like. By mortar is meant a mixture of different lyotropic liquid crystalline or isotropic phases of the solution, which include water, liquid additives and relatively water-soluble soaps or surfactants. These compositions should typically contain 50 to 60% solids, 20 to 30% lyotropic liquid crystalline phases, and about 10% isotropic liquid.

In the manufacture of detergent compositions by casting, the molded system is brought to a flowing state by raising the temperature, filled into molds and then cooled. This technology is commonly used to produce transparent •

- 2 · · ···· personal detergent tablets (cubes) containing, among other ingredients (such as soap and synthetic surfactants) typically 15 to 50% of expensive ingredients such as ethanol, polyhydric alcohols, sugars and the like, added at the time of casting.

U.S. Patent 4,155,293 (Amway, 1979) and WO 96/04361 (P&G, 1996) discloses a solid transparent soap bar comprising soap, synthetic surfactants and a water-soluble organic solvent, for example, propylene glycol. The water level in these compositions is typically about 10 to 32%.

The problem with the production of opaque soap bars by casting is that the typical compositions do not form a pourable liquid at elevated temperatures. U.S. Pat. No. 5,340,492 (P&G, 1994) claims a castable composition having a three-dimensional scaffold structure comprising a relatively strong, interconnected mesh of neutralized crystalline carboxylic acids (soaps), synthetic surfactants, and high levels of water and other liquids.

The compositions claimed in U.S. Pat. No. 5,340,492 will be soft, exhibiting a yield point of less than 75 kPa as measured using a wire cheese cutter, and therefore cannot be used as solid tablets that are strong enough to be conveniently held by hand in use. To enhance the strength of the bar, additives such as polyols (e.g., propylene glycol) are used in the examples of this patent, which are said to aid the appearance of the bar. This patent does not provide any composition in which cube appearance aids are not incorporated, and synthetic surfactants are also present in the composition. These cube appearance aids are costly and also reduce the amount of foam and the rate of formation.

• ·

In the co-pending patent application of the present inventors (717 / Bom / 99) it has been reported that incorporating small amounts of salting-out electrolytes into a melt cast detergent containing fatty acid soap, detergent active and very high amounts of water or liquid benefit agents provides solid, firmly shaped cubes having a yield point greater than 75 kPa as measured by a wire cheese cutter. These compositions can be held by hand, are economical, highly foaming, and exhibit good performance in use. The fatty acid soap of the aforementioned application is the soap of one or more of the neutralized C ₆ -C ₂₄ fatty acids.

All combinations of neutralized fatty acids selected to form soap for incorporation into the washing bars will not provide a solid product upon cooling from casting from elevated temperatures to room temperatures in the range of 20-35 ° C. It is therefore necessary to optimize the fatty acid soap combination to obtain a wash bar with sufficient stiffness at room temperatures so that it can be conveniently gripped during use. Furthermore, it is essential that the cube retains hardness even at natural ambient temperatures, generally manifested during storage and transport.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide the desired combination of fatty acids to form soap in melt cast bar formers containing very high levels of water or liquid benefit agents such that the detergent form solid tablets at temperatures above 20 ° C and retain stiffness at least up to 40 ° C.

• · ···

Thus, the present invention relates to melt cast solid shaped detergents which form a solid product at temperatures above 20 ° C, retain stiffness up to at least 40 ° C, and comprise:

(a) 2 to 50 (XJ% by weight saturated fatty acid soap comprising one or more of the C ₆ -C ₂₄ fatty acid salts; (b) 2 to 40% by weight detergent active; (c) 0.5 to 20% and (d) 30 to 80% by weight of water and optionally other liquid benefit agents, wherein the saturated soap comprising one or more of the C ₆ -C ₂₄ fatty acid salts is characterized in that its (XJ% solution in water to form a liquid phase having a viscosity of less than 50 Pa.s at a shear rate of 1 / s at a temperature range of 50 to 100 ° C, showing phase separation, the presence of a solid upon cooling down to 20 ° C, and said solid phase present during at least temperature 40 ° C.

Cooling or heating to demonstrate the solid phase is preferably carried out at a rate of from 0.1 ° C / minute to 10 ° C / minute, and more preferably at a rate of 1 ° C / minute. The presence of a solid phase is preferably demonstrated using a low field NMR technique, wherein the solid phase exhibits Gaussian decay with a T2 < 15 ps relaxation time constant. While using this nuclear magnetic resonance technique to demonstrate solid phase, it is preferable to equilibrate the sample (equilibrate) at the detection temperature for 30 minutes.

It is preferred that the detergent active is predominantly non-soap.

• ·

According to another aspect of the present invention there is provided a method of making a solid shaped detergent composition comprising the steps of:

(a) selecting a fatty acid soap comprising one or more of the salts

C ₆ -C ₂₄ fatty acids, so that the soap solution in water forms a liquid phase with a viscosity of less than 50 Pa.s at a shear rate of 1 / s at a temperature range of 50 to 100 ° C, shows phase separation, solids present during cooling up to 20 ° C and said solid phase is present during heating to at least 40 ° C;

(b) mixing said fatty acid soap with 2 to 40% detergent active, 0.5 to 20% salting electrolyte and 30 to 80% water and optionally other liquid benefit agents;

(c) melting the mixture of step (b);

(d) pouring said melt is mold to obtain the desired shape; and (e) cooling the mold under quiescent conditions to achieve solidification.

According to a preferred aspect of the present invention there is provided a method for producing a cast-in-pack of a solid molded detergent composition, comprising the steps of:

(a) selecting a fatty acid soap comprising one or more of the salts

C ₆ -C ₂₄ fatty acids, so that the soap solution in water forms a liquid phase with a viscosity of less than 50 Pa.s at a shear rate of 1 / s at a temperature range of 50 to 100 ° C, shows phase separation, solids present during cooling up to 20 ° C and said solid phase is present during heating to at least 40 ° C;

(b) mixing said fatty acid soap with 2 to 40% detergent active, 0.5 to 20% salting electrolyte and 30 to 80% water and optionally other liquid benefit agents;

• ·

6 (c) melting the mixture of step (b) and pouring it into a preformed polymer mold to obtain the desired shape;

(d) the mold is sealed; and (e) cooling the mold under quiescent conditions to achieve solidification.

The present invention relates to melt cast solid shaped detergent compositions, in particular comprising a selected fatty acid soap comprising one or more of the C ₆ -C ₂₄ fatty acid salts, such that the soap solution in water forms a liquid phase having a viscosity of less than 50 Pa.s at shear It has a phase separation, the presence of a solid during cooling down to 20 ° C, and said solid phase is present during heating to at least 40 ° C. Cooling or heating to demonstrate the solid phase is preferably performed at a rate of 0.1 ° C / minute to 10 ° C / minute, and more preferably at a rate of 1 ° C / minute. Preferably, the presence of a solid phase is demonstrated using a low-field nuclear magnetic resonance technique, wherein the solid phase exhibits Gaussian decay with a T2 < 15 με relaxation time constant. During use of the low-field nuclear magnetic resonance technique to demonstrate solid phase, it is preferred to equilibrate the sample at a detection temperature for 30 minutes.

The solid shaped cubes of the composition of the invention are sufficiently rigid to be conveniently gripped by hand, are economical, highly foaming, and exhibit good in-use properties. The compositions also exhibit a yield point value greater than 75 kPa as measured by an automatic penetrometer.

Fatty acid soap

The saturated fatty acid soap is preferably selected from one or more of saturated C ₆ -C ₂₄ fatty acid salts. Used soap ····

- 7 may be the sodium, potassium, magnesium, aluminum, calcium or lithium salt of saturated fatty acids. Particularly preferred is a soap obtained as the sodium or potassium salt of a saturated fatty acid.

The saturated fatty acid soap in the composition is preferably 5 to 50% by weight and even more preferably 5 to 40% by weight.

The viscosity of the soap-water system is measured over a temperature range of 50 to 100 ° C using a Carri-Med rheometer (model CSL 500 from TA Instruments) at a shear rate of 1 / s. Viscosity measurements are taken at steady state flow using a cone and plate configuration of 2 cm diameter and 1 degree 58 minutes with a correction of 55 µm, along with a solvent trap.

The soap-water melt is cooled at an elevated temperature to a temperature of up to 20 ° C to determine the temperature at which the phases separate and form a solid phase. Thereafter, the system is heated to indicate that said solid phase is present at a temperature of at least 40 ° C upon heating. The presence of a solid phase is demonstrated using nuclear magnetic resonance with adjustable temperature accessories, said solid phase exhibiting Gaussian decay with a relaxation time constant T _{2 of} <15 ps. For this, the procedure described by M. Suresh Nadakatti: Modified Data Handling for Rapid Low Field NMR Characterization of Lyotropic Liquid Crystal Composites; J. Surfactants and Detergents, Vol. 2, No. 4, pages 515-521, 1999.

Detergent active substances

The compositions of the present invention comprise detergent active agents, which may be soap or non-soap. Priority is ···· ♦

·· · ·· ·

8 provides the use of a non-soap detergent active which is selected from anionic, nonionic, cationic, amphoteric or zwitterionic surfactants or mixtures thereof.

Suitable anionic detergent active compounds are the water-soluble salts of organic sulfation reaction products having an alkyl radical of 8 to 22 carbon atoms in the molecular structure and a radical selected from sulfonic acid or sulfuric acid ester radicals and mixtures thereof. Some examples of synthetic anionic, detergent active compounds are straight alkylbenzene sulfonate, sodium lauryl sulfate, sodium lauryl ether sulfate, alpha olefin sulfonate, alkyl ether sulfate, long chain aliphatic methyl ester sulfonate, alkyl isethionate and the like.

The cations that are most suitable for the above-mentioned types of detergent active compounds are sodium, potassium, ammonium cation and various amines, for example monoethanolamine, diethanolamine and triethanolamine.

Suitable nonionic detergent active compounds can be broadly described as formed by the condensation of alkylene oxide groups that are hydrophilic in nature with an organic hydrophobic compound, which may be aliphatic or alkylaromatic in nature. Conventional nonionic surfactants are the condensation products of aliphatic alcohols having 8 to 22 carbon atoms in straight or branched chain configuration with ethylene oxide, such as coconut oil-ethylene oxide condensate having 2 to 15 moles of ethylene oxide per mole of coconut alcohol. Some examples of nonionic surfactants are ethylene oxide (EO) alkylphenol condensate, 10 E tallow alcohol condensate, alkyldemethylamine oxides, lauryl monoethanolamide, sugar esters and the like.

··· *

- 9 * «♦ ·

Some examples of the amphoteric detergent active compound are coconut amidopropyl betaine, coconut betaine and the like.

Optionally, it is also possible to incorporate cationic or zwitterionic detergent active compounds into the compositions of the present invention.

Further examples of suitable detergent-active compounds are provided in the following well known textbooks: (i) Surface Active Agents, Volume 1 by Schwartz and Perry, (ii) Surface Active Agents and Detergents, Volume 2 by Schwartz, Perry and Berch, (iii) Handbook of Surfactants, MR Porter, Chapman and Hall, New York, 1991.

The detergent-active compound to be used in the detergent composition of the invention is preferably an anionic detergent-active compound and will generally be up to 50% and more preferably from 2 to 30%.

Salting electrolytes

The salting-out electrolytes for use in this composition are selected from those listed in the Hofmeister category or in the lyotropic category. The salting-out electrolytes are generally those in which the lyotropic number for the electrolyte anion is greater than 10. Some examples of anions with a lyotropic number greater than 10 are NO ₂ , CIO ₃ ; Br; NO ₃ ; CIO ₄ ; AND; CNS; C ₆ H ₅ SO ₃ ; C ₆ H ₄ CH ₃ SO ₃ 'and Cr ₂ O ₇ ² '. Preferred examples of salting-out electrolytes for use in the compositions of the present invention are the alkali metal salts of the above anions. The most preferred examples of salting-out electrolytes for use in the compositions of the present invention are sodium toluene sulfonate, sodium cumene sulfonate, and sodium xylene sulfonate.

· ♦ ·· ♦ · ·· ··· ♦

Other examples of salting-out electrolytes may be selected from those described in (i) K. D. Collins and M. W. Washabaugha, Quart. Roar. Biophys. 18, 323 (1985); (ii) P. Schuster, G. Zundel and C. Sandorfy, The Hydrogen Bond, Recent developments in theory and experiments, Volume 3, North-Holland Publishing Col, Amsterdam, New York, Oxford, 1976.

Liquid benefit agents

According to a preferred aspect of the invention liquid skin-beneficial materials are included in the composition, such as moisturizers, emollients, sunscreens, and anti-aging compounds. Examples of humectants and wetting agents include polyols, glycerol, cetyl alcohol, Carbopol 934, ethoxylated castor oil, paraffin oils, lanolin and derivatives thereof. Silicone compounds may also be included as silicone surfactants, for example DC3225C (from Dow Corning) and / or silicone emollients, silicone oils (DC-200 from Dow Corning). The sunscreens may be 4-tertiary butyl 4'-methoxydibenzoylmethane (available under the trade name PARSOL 1789 from Givaudan) and / or 2-ethylhexylmethoxycinnamate (available under the trade name PARSOL MCX from Givaudan), or other sunscreen compounds UV-A and UV-B radiation.

Optional additives

Other optional ingredients such as hair conditioners, fillers, colorant, perfume, opacifier, preservatives, one or more of the water-insoluble particulate materials such as talc, kaolin, polysaccharides, and other conventional ingredients may be incorporated into the composition of the invention.

· T · 4

Way

The method of making the solid shaped detergent compositions of the present invention comprises the following steps, wherein

(a) selecting a fatty acid soap comprising one or more of the salts

C ₆ -C ₂₄ fatty acids, so that the soap solution in water forms a liquid phase with a viscosity of less than 50 Pa.s at a shear rate of 11s at a temperature range of 50 to 100 ° C, shows phase separation, solids present at 20 ° C and said solid phase is present during heating to at least 40 ° C;

(b) mixing said fatty acid soap with 2 to 40% detergent active, 0.5 to 20% salting electrolyte and 30 to 80% water and optionally other liquid benefit agents;

(c) melting the mixture of step (b);

(d) pouring said melt is mold to obtain the desired shape; and (e) cooling the mold under quiescent conditions to achieve solidification.

The mold may be suitably selected to produce nearly pure tablets or cubes / blocks. The bars / blocks may be further formed into lump soap.

If the solid soap is made using a thermoformed polymer of almost pure shape, the mold is preferably sealed to obtain a detergent cast in the package. To obtain the detergent cast in the packaging, the mold is preferably closed immediately after filling.

The invention will now be illustrated with reference to the following non-limiting examples.

- 12 _ · * tt * · ♦ «« «4 4 * * 4 4 4 4 4 4 4 4 4

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Screening of fatty acid soap mixture for detergent production

Several soap and water mixtures, where the soap was obtained from a mixture of lauric acid (C ₁₂ ), myristic acid (C ₁₄ ), palmitic acid (C ₁₆ ) and stearic acid (C ₁₈ ), were placed in 2 liter round bottom flasks . The fatty acid soap ratio was varied as shown in Table 1.

The batch temperature was raised and maintained at 80 ° C to obtain a pourable liquid having a viscosity of approximately 10 Pa.s at a shear rate of 1 / s.

Low Field Nuclear Magnetic Resonance Imaging

A low-field nuclear magnetic resonance technique was used to demonstrate the presence of a solid phase in soap-water systems. The solid phase shows Gaussian decay with a relaxation time constant T ₂ <15 ps.

The low-field nuclear magnetic resonance used for these studies was mediated by M / s Resonance Instruments, UK (model MARAN 25). This apparatus had the following characteristics: (i) a 600 W transmitter that produced 90 ⁰ pulses of approximately 2 ps and (ii) a 5 MHz digitizer that allowed the collection of two reference points in 1 ps. The presence of solid phase in soap-water systems was demonstrated by the following reference: M.

• ·

- 13 · »« ·· ^of "♦ • * * i • ·· :: * ϊ • · * · * ·« ·· ·· ··

Suresh Nadakatti: Modified Data Handling for Rapid Low-Field NMR Characterization of Lyotropic Liquid Crystal Composites; J. Surfactants and Detergents, Vol. 2, No. 4, pages 515-521, 1999.

The molten soap-water system was placed in a 10 mm NMR tube. This tube was placed in a sample chamber of a low-field NMR device. The temperature was raised to 80 ° C using the adjustable temperature instrument equipment. Thereafter, the system was cooled at 5 ° C intervals to a temperature of up to 20 ° C, equilibrated (equilibrated) at each temperature for 30 minutes. The temperature at which phase separation occurs and a solid phase is formed has been recorded. The system was then heated again to verify that said solid phase was present during heating to at least 40 ° C.

Table 1

% (% wt. example 1a 2a 3a 4a 5a 6a 7a 8a sodium stearate (C18) 16 18 28 4 2 2.7 6.3 - sodium laurate (C12) 4 2 2 16 18 12 4 5 sodium palmitate (C16) - - - - - 3.3 7.7 - sodium myristate (C14) - - - - - - - 25 water 80 80 70 80 80 82 82 70 workability at 80 ° C Yes Yes No Yes Yes Yes Yes Yes solid phase temperature during cooling (° C) 55 60 60 0 5 20 May 50 50 temperature to which the solid phase is present during heating (° C) 60 60 60 30 35 35 55 60

- 14 44 • 44 «» 4 444 * * 4 4 • 4 44 ·· 44 ·· # 444 • 4 · * 4 ·

The data presented in Table 1 show that only in Examples 1a, 2a, 7a and 8a were pourability, the temperature at which the solid phase is formed during cooling and the temperature to which the solid phase is present during heating, in accordance with the present invention.

Example 2

Process for making bar soap

Based on the screening described in Example 1, fatty acid mixtures corresponding to Examples 1a to 8a were placed in 2 L round bottom flasks and mixed with non-soap detergent active compounds such as alpha-olefin sulfonate (AOS) or sodium lauryl ether sulfate (SLES), with a salting electrolyte such as sodium toluene sulfonate (STS) and water as described in Table 2 below. The batch temperature was raised to 80 ° C. An aqueous sodium hydroxide solution was added to the mixtures to neutralize fatty acids. The batch temperature was maintained at 80 ° C to obtain a clear solution. The detergent melt was poured into the thermoformed polymer molds at 80 ° C and the inlet of each mold was closed. The molds were allowed to cool to solidify the soap, thereby obtaining detergent (washing) tablets cast in a container.

The stiffness of the cubes produced was determined by the yield strength as described below.

Measurement of yield point

Detergent tablets were loaded with thermostats set at 25 ° C and 40 ° C and allowed to equilibrate for 4 hours. The yield point of the tablets at 25 ° C and 40 ° C was measured using an automatic penetrometer as described below.

- 15 ··· 9 ···

The automatic penetrometer used to measure the yield point was the PNR 10 model from M / s Petrotest Instruments GmbH. A standard hollow cone (part no. 18/0101, according to ASTM D 217 - IP 50) was used together with a punch (part no. 18-0042) for measurement. The cone consisted of a brass conical body with a detachable reinforced steel tip. The total weight of the cone was 102.5 g. The total weight of the movable punch was 47.5 g. The total weight of the punch cone thrust into the detergent tablet, i.e. 150 g reagent. to 200 g and 250 g). Sample yield values were measured at 25 ° C and 40 ° C using a standard procedure, including the following steps:

1. The detergent tablet was placed on a penetrometer table.

2. The penetrometer measuring device was lowered so that the penetrometer tip touched the tablet without penetrating it.

3. The measurement itself was started by pressing the start button.

4. The depth of penetration was read in millimeters by indicator.

5. The measured penetration depth value was used to calculate the yield strength of the detergent tablet using the following equation:

yield point = exerted force / planned area of cone = (mxg) χ 10 ³ / [π (p tg 1/2 θ + 1/2 tip diameter) ² ] where yield point is given in kPa m: total weight impinging on flat cube (tablet) surface in kg g: gravity acceleration in meters / sec ² p: penetration in mm q: cone inclination (30 degrees) tip diameter = 0,359 mm

- 16 · * ♦ * ·· * · ··· · ':. ·:. :

According to the above equation, at a measured penetration depth of less than 10 mm after using a total weight of 200 g, the yield strength of the detergent tablet is greater than 75 kPa. For the total weight impinging on the detergent tablet 150 g, 200 g and 250 g, 3 yield strength values were calculated and the average of these 3 values was taken as the yield strength of the detergent (wash) tablet.

Table 2

% (% wt. example 1b 2b 3b 4b 5b 6b 7b 8b sodium stearate (C18) 16 18 28 4 2 2.7 6.3 - sodium laurate (C12) 4 2 2 16 18 12 4 5 sodium palmitate (C16) - - - - - 3.3 7.7 - sodium myristate (C14) - - - - - - - 25 SLES 5 5 8 5 5 8 - - AOS - - - - - - 8 - coconut betaine - - - - - - - 8 STS 2 2 3 2 2 3 3 2 water 73 73 59 73 73 71 71 60 yield point (kPa), Deň: 22 ° C 252 363 <75 chap. chap. chap. 132 481 yield point (kPa), Deň: 32 ° C 186 158 <75 chap. chap. chap. 80 343

The data presented in Table 2 shows that only if the soap-water system conforms to the present invention will such a system produce washing bars that solidify and provide solid products upon cooling to a temperature greater than 20 ° C and retain stiffness up to at least 40 ° C. Deň: 32 ° C. This is confirmed by the data on the yield strength of the washing cubes · * 4 · ·· * ··· »* ····

17 (Examples 1b, 2b, 7b, and 8b) having values greater than 75 kPa when the soap-water system found is in accordance with the invention (Examples 1a, 2a, 7a and 8a). If the soap-water system does not meet the screening requirements, the detergent product produced using such a soap will not form solid bars.

Represented by:

Claims (10)

PATENT CLAIMS 1. A melt-casting detergent having a stiffness of at least 40 DEG C., comprising: (a) 2 to 50 (X _a )% by weight of a saturated fatty acid soap comprising one or more of the C ₆ -C ₂₄ fatty acid salts; (b) 2 to 40% by weight of a detergent active; 20% by weight salting electrolyte, and (d) 30 to 80% water; wherein the fatty acid soap present forms an X _and % solution in liquid phase water having a viscosity of less than 50 Pa.s at a shear rate of 1 / s at a temperature range of 50 to 100 ° C, exhibits phase separation, presence of solid phase during cooling up to 20 ° C and said solid phase is present during heating to at least 40 ° C. 2. A melt cast detergent composition according to claim 1 wherein the detergent active is a non-soap detergent active selected from ionic, nonionic, cationic, amphoteric or zwitterionic surfactants or mixtures thereof. The melt cast detergent composition of claim 1 or 2, wherein the fatty acid soap is a sodium, potassium, magnesium, aluminum, calcium or lithium salt of a saturated C ₆ -C ₂₄ fatty acid. The melt cast detergent composition of any one of claims 1 to 3, wherein the saline electrolyte has a lyotropic number for the anion of less than 10. a metal sign whose C _r H _r SO, ', - 19 The melt casting composition of claim 4, wherein the salting electrolyte is an alkali anion salt selected from NO ₂ ', _{C 10} ', Br ', NO ₃ ', _{C 10} ', I', CNS; C ₆ H ₄ CH ₃ SO ₃ 'or Cr ₂ O ₇ ² '. 6. A melt cast detergent composition according to any one of claims 1 to 3 wherein the composition further comprises a liquid benefit agent. 7. A melt cast detergent composition according to claim 6 wherein the liquid benefit agent is selected from humectants, emollients, sunscreens, or anti-aging compounds. 8. A process for the production of a melt-cast, solid-shaped detergent composition comprising the steps of: (a) selecting a fatty acid soap comprising one or more of the salts C ₆ -C ₂₄ fatty acids, so that the soap solution in water forms a liquid phase with a viscosity of less than 50 Pa.s at a shear rate of 1 / s at a temperature range of 50 to 100 ° C, shows phase separation, solids present during cooling up to 20 ° C and said solid phase is present during heating to at least 40 ° C; (b) mixing said fatty acid soap with 2 to 40% detergent active, 0.5 to 20% salting electrolyte, and 30 to 80% water; (c) melting the mixture of step (b); (d) pouring the melt is mold to obtain the desired shape; and (e) cooling the mold under quiescent conditions to achieve solidification. The method of claim 8, wherein step (b) further comprises adding a liquid benefit agent. ·· «·» 44 44 44 444 - 20 / Z ^ 003- Josy 10. A fixed-form detergent composition, which is produced by the method of claim 8 or 9.