TECHNICAL FIELD

The invention provides a process for the preparation of a soap composition.

BACKGROUND OF THE INVENTION

Everyday personal cleaning is one of life necessities.

The cleaning process usually employs a soap material (composition) to aid soil removal. This is commonly in the form of a solid bar. The bar shape aids holding of the soap and moving it around the user's body. Soap bar compositions are disclosed in, for example, US2003/020777, WO2006/128313 and WO2010/089269.

The soap bars may be made in an extrusion process. The extrusion process may include multiple stages such as a preliminary stage for the initial preparation of soap noodles and one or more secondary stages where the soap noodles are extruded for a second / further time. Certain components of the soap may go through all of the extrusion stages or may be added to one of the latter extrusion stages. The final extruded composition may receive further treatment, such as moulding into bar shapes.

This kind of single extruder system lends itself to the production of homogenous soaps wherein all of the components are evenly distributed throughout the final soap. With the use of a single extruder system (whether using one or more extrusion stages) it is difficult / impossible to produce a non-homogenous / variegated soap; certainly with any level of predictability / control over the overall soap composition.

Such soaps are desirable from a visual consideration and can be appealing to users.

It is of course possible to use a complex extrusion system with multiple extruders or to modify the extruder to dose or inject additional ingredients such as coloured ingredients to achieve a non-homogenous soap. However, such a system has a high cost associated therewith; in terms of its initial set-up cost and then the running / maintenance costs.

US 6,248,703 discloses a process for producing a bar soap comprising capsules which are strong enough to withstand the extrusion process and which are able to release their contents during use of the bar soap by the consumer.

It is an object of the present invention to obviate or mitigate one or more of the technical issues outlined above. BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a process for the preparation of a soap composition comprising the steps of: a) Mixing together at least soap noodles and frangible particulates comprising a benefit agent, and

b) extruding the mixture obtained from step a) through an extruder, and wherein the frangible particulates are at least substantially ruptured during the extrusion step b.

It has been found that with the use of frangible particulates, a benefit agent can be distributed throughout the soap composition. It is self-evident that in order to provide for the benefit agent to be distributed throughout the soap, the frangible particulates are ruptured during the extrusion process thus releasing the benefit agent from the particulates. This rupturing of the frangible particulate provides for the distribution of the benefit agent throughout the soap during the extrusion process. The rupturing may be effected by either the complete disintegration of the frangible particulates, or, by substantially rupturing the frangible particulates such that the coherency of the particulates is reduced sufficiently to allow the benefit agent contained within the frangible particulates to be released and distributed in the soap composition. The distribution is preferably in a non-homogenous / variegated fashion. Moreover, there is a high level of predictability / control over the overall soap composition.

With the incorporation of the frangible particulates it has been found that a non- homogenous soap may be produced in a simple / cost effective manner. The use of the frangible particulate avoids the need for multiple extruders and / or the need for multiple hoppers to be loaded with differing soap compositions. Furthermore, the present invention also obviates the need for the extruder to include a dosing or injection system to add certain additional ingredients to the extrudate (such as coloured ingredients).

DETAILED DESCRIPTION OF THE INVENTION

Frangible Particulates Preferably the frangible particulates make up from 0.01 to 20wt% of the overall soap composition.

Generally, the frangible particulates comprise a shell, that shell being frangible. Typically the shell comprises a polymeric material. The shell contains the benefit agent within the particulate (encapsulates it) until the point of rupture which occurs during the extension step (step b). Preferred materials for the shell include cellulosic materials, especially CMC (carboxym ethyl cellulose). However, it is possible to use any material which is frangible and which substantially ruptures in the extrusion step.

Preferably the particulate has an average particle size (by mass) in the range of 0.001 to 10mm, more preferably 0.1 to 8mm, most preferably in the range 1 to 5mm, such as 2mm to 4mm. It is especially preferred that the particulate has an average particle size (by mass) of about 3mm.

The frangible particulates may be contained in a liquor prior to addition to the soap noodle. Preferably the liquor is suitable for incorporation in a soap composition. As such, preferably the liquid comprises one or more of water or an oxygen / hydroxyl moiety containing solvent (such as an alcohol (such as a C2-6 alkyl mono-alcohol), a polyol (such as a glycol or glycerol) or glycol ether (such as polyethylene glycol)). Alternatively, the frangible particulates may be separated by any suitable means from any liquor in which they are held and may be added to the soap noodles as substantially dry particulates.

Most preferably the benefit agent comprises a dye or pigment. In this preferred embodiment by the incorporation of the benefit agent in the frangible particulates, and by virtue of the subsequent extrusion process, the present invention provides for nonuniform distribution of colour to provide variegated soap having at least two colours, white being considered a colour. Thus the soap preferably has a basic colour with speckles or streaks of at least one other colour. Often the basic soap colour is generally white / cream, due the soap components, and the dye or pigment is preferably selected to contrast with such a colour. Preferred dye colours includes red, blue and green. It is of course possible to add dyes or pigments to the soap noodle, or as a separate ingredient to the mixture which is extruded, in addition to any dyes or pigments contained within the frangible particulates. This provides for a varigated soap bar having a first colour e.g. (blue) with a second colour present as streaks or speckles (e.g. red).

Soap Noodles According to the present invention, a soap base is used to produce the soap noodles used in step a) of the process of the invention. These soap noodles are used in the process of the present invention, together with the frangible particulates, to produce the soap composition.

The soap base for use in preparing the soap noodles and thus the solid soap composition of the present invention can be composed substantially entirely of sodium and / or potassium salts of fatty acids containing from 8 to 18 carbon atoms or a mixture thereof. For example, fatty acids having 16 or 18 carbon atoms, and mixtures thereof may be used. The fatty acids can be either saturated or unsaturated. The soap base may be composed entirely of the potassium salts of tallow fatty acids. The sodium and / or potassium soap used can be prepared by either saponification of the triglycerides or by neutralization of the free fatty acids. If the triglycerides are saponified with sodium and / or potassium hydroxide, it is not necessary to remove the glycerine, although this is preferred since the glycerine is a valuable by-product. Preferably, the triglycerides are first split and the free fatty acids are recovered. The free fatty acids are then reacted with the appropriate hydroxide (either sodium hydroxide or potassium hydroxide) to produce the desired sodium or potassium salts of the fatty acids.

The overall soap composition may be translucent or opaque or it may have a translucent and an opaque portion. For an opaque composition a wide variety of synthetic detergents can be satisfactorily employed in the solid soap composition of this invention. The general class of synthetic detergents most commonly used for use in the present soap composition can be defined as an anionic-type synthetic detergent having pronounced detergent power and including in its molecular structure an alkyl radical containing from 6 to 18 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. In addition, the anionic-type synthetic detergent for use in this invention is preferably normally solid, although paste or liquid type detergents can be employed. The main types of detergents falling within the above class are: (I) the alkyl aryl sulfonates; (2) the alkyl sulfates; (3) the sulfonated fatty acid amides; and (4) the sulfonated monoglycerides.

The alkyl aryl sulfonates are preferred, but the other types of detergents listed can be employed. Either the sodium or potassium salts of the anionic-type detergents can "be used. Specific examples of alkyl aryl sulfonates which can be employed are sodium or potassium dodecyl benzene sulfonate, sodium or potassium octadecylbenzene sulfonate, and sodium or potassium octyl naphthalene sulfonate. Specific examples of the alkyl sulfates which can be employed are the sodium and potassium salts of L dodecyl, hexadecyl-and octadecyl sulfates. Specific examples of suitable sulfonated fatty acid amides include the sodium and potassium salts of sulfonated amides of higher fatty acids such as the sodium or potassium salt of the oleic acid amide of methyl taurine. The sulfonated monoglycerides which can be employed are preferably either sodium or potassium salts of higher fatty acids of monoesters or lower molecular weight hydroxy alkyl sulfonates such as the oleic acid ester of the sodium salt of isethionic acid and the monococonut oil fatty acid ester of 1 ,2 hydroxy propane 3 sodium sulfonate. It will be understood that the specific synthetic detergents mentioned are only illustrative of those falling within the scope of this invention, and that other equivalent detergents can be substituted therefor.

Other ingredients can be incorporated in the opaque composition to improve the properties thereof; for example, a soil redeposition retarder such as carboxymethyl cellulose (C.M.C.). This is separate to any carboxymethyl cellulose used to produce the shell of the frangible particulates. About 1 % of C.M.C. on the basis of the total weight of the composition is usually sufficient for this purpose. Other relatively inert ingredients such as sodium sulfate-can be included without harmful effect. A number of synthetic detergents such as the alkyl aryl sulphonates, contain sodium sulfate in addition to the active detergent in their commercially available form. Such detergents can be incorporated directly in the soap base or noodles, or, can be added separately to be present in the final soap composition.

Starch, talc or other fillers can also be incorporated in the soap base, soap noodles or soap composition if desired. Talc is a magnesium silicate mineral material, with a sheet silicate structure represented by the chemical formula Mg3Si ₄ Oio(OH)2, and may be available in the hydrated form. Talc has a plate-like morphology, and is substantially oleophilic / hydrophobic. Examples of other optional insoluble inorganic particulate materials include alumino silicates, aluminates, silicates, phosphates, insoluble sulfates, borates and clays (e.g., kaolin, china clay) and their combinations. Organic particulate materials include: insoluble polysaccharides such as highly cross-linked or insolubilized starch (e.g., by reaction with a hydrophobe such as octyl succinate); synthetic or natural polymers such as various polymer lattices and suspension polymers and mixtures thereof.

Where present the level of inorganic particulate should be between 0.01 percent and 20 percent by weight of composition.

A mildness/moisturizing aid component could be also present. This can provide provides superior skin conditioning without negative tactile attributes such as greasy, sticky or tacky skin feel. Preferred mildness/moisturizing aids include silicones. The silicone materials useful in the present invention are generally non-volatile and may be either a polyalkyl siloxane, a polyaryl siloxane, a polyalkylaryl siloxane, a polysiloxane with amino functional substitutions, or a polyether siloxane copolymer. The siloxanes useful in the present invention may be end-capped with any number of moieties, including, for example, methyl, hydroxyl, ethylene oxide, propylene oxide, amino, and carboxyl. Mixtures of these materials may also be used and are preferred in certain executions. Additionally, volatile silicones may be used as part of the silicone mixture so long as the final mixture is non-volatile.

Where present the level of mildness/moisturizing aid should be between 0.01 percent and 10 percent by weight of composition.

Other performance chemicals and adjuncts may be added as desired. Adjunct materials including germicides, perfumes, colourants, and dyes / pigments such as titanium dioxide may also be present.

In the case of translucent formulas preferably a solvent is present. Preferred types of solvents include polyols. Many types of polyols are available including: relatively low molecular weight short chain polyhydroxy compounds such as glycerol and propylene glycol; sugars such as sorbitol, manitol, sucrose and glucose; modified carbohydrates such as hydrolyzed starch, dextrin and maltodextrin, and polymeric synthetic polyols such as polyalkylene glycols, for example polyoxyethylene glycol (PEG) and polyoxypropylene glycol (PPG). Preferred polyols are relatively low molecular weight compound which are either liquid or readily form stable highly concentrated aqueous solutions. These include low molecular weight polyols and sugars. Especially preferred polyols are propylene glycol, glycerol, sorbitol and their mixtures.

Where present the level of polyol should be between 0.5 percent and 20 percent by weight of the soap composition.

Extrusion Process Preferably the extrusion process is continuous. The extrusion process may further comprising a cutting and / or a moulding step, such that the final soap is in the form of a shaped bar. Examples

Tables 1 , 1 a, 2 and 2a show formula cards of two formulations made using the frangible particulate. They both rendered a marbleized effect.

MANUFACTURING METHOD:

I. ACTIVE (TCC) SLURRY PRE-MIX

Conditions: Ambient temperature.

1 . Add the formula quantity of Fragrance into a suitable mixing vessel.

2. Slowly add the formula quantity of TRICLOCARBAN (TCC) (or any suitable active) to the mixing vessel.

3. Mix well to get uniform slurry.

Note: The pre-mix has to be used within one day. Mix the pre-mix before adding to main batch to ensure uniformity of TCC.

(The pre-mix step is added to provide an antibacterial effect as an antibacterial agent is added in this step but it is not a condition for the invention. The process is equally applicable to non-antibacterial soaps),

II. BATCH MAIN MIX

Procedure Conditions/ Duration/Parameters

1 . Check moisture content of soap N/A

noodles and adjust the quantity of

soap noodles and water if needed.

2. Weigh and check the formula Ambient temperature.

quantity of Soap noodles.

3. Discharge the soap noodles into the Ambient temperature. 3-5 Minutes or until sigma mixer. Mix until the noodles are it's needed.

crushed.

4. Add the formula quantity of Talc to Ambient temperature. 2 minutes.

the sigma mixer and start mixing.

5. Add the formula quantity of titanium Ambient temperature. 2 Minutes.

dioxide and sodium olefin sulfonate

(AOS powder) to the sigma mixer and

start mixing.

6. Add TCC slurry pre-mix followed by Ambient temperature. 4 Minutes.

glycerin and silicone emulsion to main

batch while mixing and ensure all the ingredients are well mixed with soap

noodles.

Note: Please, ensure simplex plodder

is running to avoid any issue with

soap getting stuck in the hopper.

7. Refining & Milling: Screen Size for Simplex Plodder - 30 mesh (0.595mm mesh)

Transfer the mixture into the simplex

plodder and roll mill. Gaps for Roll Mill:

bottom to middle - 0.3 mm

middle to top - 0.15 mm

8. Duplex Vacuum Plodder: Vacuum Setting: 450 to 550 mm Hg

Transfer the mixture from roller mill Cone temperature setting: 40-50°C to duplex vacuum plodder and

Chilled water inlet temperature: 7-9°C simultaneously add crushable color

beads. (The beads will be crushed

Chilled water outlet temperature: 8-10°C in this stage releasing color in a

random pattern, which provide the

marbleized effect)

Extrude the soap into slug.

9. Cut slug in to billets Billet temperature: 35-42°C

10. Stamp the billets according to the N/A

required shape

1 1 . Perform QC routine analysis N/A

required for product release.

12. Upon QC approval, pack the soap N/A

bars into appropriate packaging.

Table 1

Table 1 a

Raw Material %w/w

Soap Noodle 85.5500

Filler 8.5000

Pigment 0.3000

Synthetic surfactant 0.7500

Frangible particle with d) /e 1 .0000

Glycerine 1 .1000

Skin conditioning agent 0.5000

Fragrance 1 .3000

Deionized Water 1 .0000

100.00

This contains a filler (talc) and it is an opaque formulation (the background ^' completely white).

Table 2

Active P remix

Raw material

Fragrance 0-3

Active 0-1

100.00000 Table 2a

This is a semi translucent formulation with high glycerin content. The background is not white so the marbleized effect is dark pink over a very light white-pinkish color.

The Lipospheres in Tables 2 and 2A are the frangible particulates; they comprise an outer shell of carboxymethyl cellulose with a pigment (the benefit agent) contained within the shell.