DESC:Field of invention

The present invention relates to a composition for improved surface finish of casted syndet base bathing bar. More particularly, the present invention relates to specific ratio of inorganic: organic structurants.

Background and prior art

Synthetic surfactant-based personal cleansing bars have attracted much interest because they can be selected to be milder to the skin than soap-based products. This mildness however, comes with negative to both the manufacturer and the consumer. The bar soap manufacturer experiences difficulties in the processibility while the consumer experiences the properties of poor lather, messy smear, bar softness and high wear rates.

WO2011/080101 teaches personal washing bar which includes a continuous phase which is substantially free of a water soluble detergent builder, the continuous phase comprising:
a. 20% to 50%, preferably 25% to 40%, more preferably 30% to 37% fatty acid soap, wherein the fatty acid soap comprises less than 39% of an unsaturated fatty acid soap by weight of the fatty acid soap;
b. A structuring system comprising:
i) From 10% to 45%, preferably 20% to 40% by weight of the of the continuous phase of a polysaccharide structurants selected from the group consisting of starch, cellulose and a combination thereof,
ii) From 6.0% to 30%, preferably 10% to 20%, by weight of continuous phase of a polyol selected from the group consisting of glycerol, sorbitol and their mixtures, and
iii) 0 to 15%, preferably 4% to 10% by weight of continuous phase of a water insoluble particulate material;
c. 0.5% to less than 3%, preferably 0.5% to less than 2.5%, of an anticracking agent selected from the group consisting of carboxymethyl cellulose, polyacrylates and mixtures thereof;
d. From 10% to 20%, preferably 15% to 18% water

wherein the continuous phase is an extrudable mass having a penetrometer hardness of 3 to 8 kg and a yield stress of 350 to 2000 kPa measured at a temperature of 40°C. Conveniently the bar has a Cracking Index of 1 or less.
US 6849585 relates to soap/free fatty acid bars in which high amounts of free fatty acid (i.e., greater than 35%, preferably greater than 40% and ratio of FFA to soap greater than 1:1) and low levels of synthetic may be used. In the bar, the free fatty acid is believed to form a complex which is believed to act as a structurant, thereby allowing less use of synthetic surfactant. The bar should require less synthetic surfactant. Total amount of unsaturated material in soap and fatty acid should be no higher than 15%. Specifically, compositions of the invention comprise:
(1) at least about 65% by wt., preferably at least 66%, more preferably at least 68%, more preferably at least 70% mixture of fatty acid soap and free fatty acid wherein at least 35%, preferably at least 37%, more preferably at least 40% by wt. more preferably more than 40% by weight of bar is free fatty acid and wherein said fatty acid soap in the bar is preferably although not necessarily produced when FFA mixes with less than 50 mol % caustic (Also preferably the ratio of FFA to soap is at least 1:1 and preferably greater than 1:1);
(2) less than 25%, preferably less than 24%, more preferably less than 20% non-soap synthetic surfactant (preferably amount of the FFA is greater than level of synthetic);
(3) less than 15%, preferably less than 14% (e.g., 2-14%) water; wherein said bar has lather of at least 50 ml, measured by BLAM, as referenced test;
wherein said bar is preferably prepared by an extrusion process; and
wherein the hardness of the extrusion bar is at least 90 kPa, preferably at least 100 kPa, as measured by cheese wire method.
However, the present invention provides a composition for improving surface finish of casted syndet bar using unique ratio of inorganic:organic structurants. The present invention relates to syndet rich personal washing bar.
Object of the invention
It is object of the present invention to overcome the disadvantages of the prior arts.
It is another object of the present invention to provide a composition for improved surface finish of casted syndet bar.
It is yet another object of the present invention to provide a composition for producing improved surface finish of casted syndet bar having a specific ratio of inorganic:organic structurants.
Summary of the invention
An aspect of the present invention is to provide a composition comprising
a) organic structurant;
b) natural or synthetic inorganic structurant; and
c) cosmetically acceptable excipients;
wherein the ratio of inorganic and organic stucturant ranges from 1:4 to 1:1.
Detailed Description of the invention
An embodiment of the present invention provides a syndet bar composition comprising organic structurant; natural or synthetic inorganic structurant; and cosmetically acceptable excipients; wherein the ratio of inorganic and organic stucturant ranges from 1:4 to 1:1.

Structurants can be defined as texturing agent which provides a better texture to the finished bar with better binding.

Organic structurants are organic in nature and may be selected from a group comprising starches such as Corn starch, potato starch, modified starch; fatty alcohols, high chain length fatty acids and combinations thereof. The amount of the same in the composition ranges from 1-10 % wt.

Inorganic structurants are inorganic in nature. Natural Inorganic structurants may be selected from a group comprising clay, kaolin, fuller’s earth, bentonite, talc and mixtures thereof.

Synthetic Inorganic structurants may be selected from a group comprising of sodium/magnesium/calcium aluminium silicate, silica and mixture thereof.
The other cosmetically acceptable excipients are stated as under

Fatty Acids are selected from a group comprising Stearic acid, Hystric acid, Palmatic acid, Myristic acid and the like. The amount of the said fatty acides ranges from 4-12 wt %.

Polymers are selected from a group comprising Hydroxymethyl Cellulose, PEG90M and the like. The amount of the said polymers ranges from 1-7 wt %.

Wax is selected from a group comprising Bees wax, Paraffin wax, Carnuba Wax and the like. The amount of the said wax ranges from 2-20 wt %.

Oil is selected from a group comprising Olive oil, Corn oil, Wheatgerm Oil, White paraffin Oil, Coconut Oil, Castor Oil and the like. The amount of the said oil ranges from 1-5 wt %.

Structurant is selected from a group comprising PEG400, PEG6000, PEG4000 and the like. The amount of the said structurant ranges from 1 to 20 wt/wt% and preferably from about 1– 15% wt/wt.

Emollients are selected from a group comprising Polydimethylsiloxane, PEG7 Amodimithicone and the like. The amount of the said structurant ranges from 0.5-2 wt %.

Emulsifiers are selected from a group comprising Sodiumcocyl Isothionate, Sodium lauryl Sulphate, Sodium salt of free fatty acids, CAPB , Alfa Olefin Sulfate and the like. The amount of the said emulsifiers ranges from 0.5-10 wt%.

The surfactants used in the composition can be surfactant chosen from group comprising, but are not limited to synthetic, anionic, zwitterionic, amphoteric, semi-polar nonionic, nonionic surfactant and mixtures thereof. The amount of the surfactant ranges from 40-65 wt %.

The surfactants used in the present invention may be selected from a group comprising, but are not limited to anionic surfactants, amphoteric surfactants, nonionic surfactants, and any combinations thereof. As it is well known in the art that surfactant materials can also be an emulsifier, the term “surfactant” does not exclude materials which also have emulsification properties.

The anionic surfactants that may be used in the present invention include but are not limited to alkyl sulfates, anionic acyl sarcosinates, anionic alkyl sarcosinates, methyl acyl taurates, N-acyl glutamates, acyl isethionates, alkyl ether sulfates, alkyl sulfosuccinates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, trideceth sulfates, protein condensates, mixtures of ethoxylated alkyl sulfates and the likes. Alkyl chains for these surfactants are C8-C22, preferably C10-C18 and, more preferably, C12-C14 alkyls.

The amphoteric surfactants which can be used in the compositions of the present invention are those which can be broadly described as derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Examples of compounds falling within this definition are sodium 3-dodecylaminopropionate, sodium 3-dodecylaminopropane sulfonate. Other amphoterics such as betaines are also useful in the present composition. Examples of betaines useful herein include the high alkyl betaines such as coco betaine, coco dimethyl carboxymethyl betaine, lauryl dimethyl carboxy-methyl betaine, lauryl dimethyl alpha-carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2-hydroxyethyl)carboxy methyl betaine, stearyl bis-(2-hydroxypropyl)carboxymethyl betaine, oleyl dimethyl gamma-carboxypropyl betaine, lauryl bis-(2-hydro-xypropyl)alpha-carboxyet-hyl betaine, etc. The sulfobetaines may be represented by coco dimethyl sulfopropyl betaine, stearyl dimethyl sulfopropyl betaine, amido betaines, amidosulfobetaines, and the like.

The nonionic surfactants useful in this invention can be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. Non-limiting examples of preferred nonionic surfactants for use herein are those selected form the group consisting of glucose amides, alkyl polyglucosides, sucrose cocoate, sucrose laurate, alkanolamides, ethoxylated alcohols and mixtures thereof. In a preferred embodiment the nonionic surfactant is selected from the group consisting of glyceryl monohydroxystearate, isosteareth-2, trideceth-3, hydroxystearic acid, propylene glycol stearate, PEG-2 stearate, sorbitan monostearate, glyceryl laurate, laureth-2, cocamide monoethanolamine, lauramide monoethanolamine, decyl glucoside and mixtures thereof. The composition of the present invention may also comprise one or more sugar based surfactants selected from but not limited to condensation products of long chain alcohols with sugar or starch polymers (e.g. decyl polyglucoside and lauryl polyglucoside), amides (e.g. cocoamide diethanolamine and cocoamide monoethanolamine), alkylene oxide derived surfactants (e.g. ceteth-6, ceteareth6, steareth-6, PEG-12 stearate, and PEG-200 glyceryl tallowate), Maltooligosyl Glucoside/Hydrogenated starch Hydrolysate and mixtures thereof. Preferred sugar based surfactants include Maltooligosyl Glucoside/Hydrogenated starch Hydrolysate and Alkyl polyglucoside.

Soaps are chosen from a group comprising but are not limited to sodium or potassium salts of stearate, laurate, myristate, palmitate, saponified glycerides such as sodium palmate, sodium palm kernelate and sodium cocoate and combinations thereof. The amount of soap ranges from 10-20 wt%.

Binders are chosen from a group comprising high molecular weight PEGs like PEG 6000, PEG 8000, poly acrylates, high molecular weight poly-ox, silicates, fatty alcohols, lanolin, sugars, tallow alcohol ethoxylates, and mixtures thereof. Other plastic binders are identified in the published literature, such as J. Amer. Oil Chem. Soc. 1982, 59, 442.. The amount of binder ranges from 0.5-4 wt%

Preservatives are chosen from a group comprising but are not limited to dimethyloldimethylhydantoin, parabens, BHT, EDTA, phenoxy ethanol phenoxy ethanol, sorbic acid, phenoxy ethanol and combination thereof.. The amount of preservatives ranges from 0.01-0.5 wt%.

Color are chosen from a group comprising but are not restricted to beta carotene, carotenoids, D&C Red 30 Talc Lake, D&C Red 7 Calcium Lake, D&C Red 34 Calcium Lake, mica/titanium dioxide/carmine pigments (e.g., Clorisonne Red from Engelhard, Duocrome RB from Engelhard, Magenta from Rona, Dichrona RB from Rona), Red 30 low iron, D&C Red Lake blend of Lake 27 & Lake 30, FD&C Yellow 5 Lake, Pigment Blue 15, Pigment violet 23, Acid red 33, Food red 1, Kowet titanium dioxide, yellow iron oxide, D&C Red 30 Lake, D&C Red 28 Lake, Cos Red Oxide BC, Cos Iron Oxide Red BC, Cos Iron Oxide Yellow, Cos Iron Oxide Yellow BC, Euroxide Red Unsteril, Euroxide Yellow Steril, Euroxide Red, Hydrophobic Euroxide Yellow, Hydrophobic Euroxide Red, FD&C Yellow no. 5, FD&C Blue no. 1, D&C Yellow 6 lake, D&C Yellow 5 Zr Lake, and mixtures thereof. The amount of color ranges from 0-1.5 wt %

Fragrance are chosen from a group comprising but are not limited to essential oils, natural fragrance, synthetic fragrances or combination thereof. The amount of color ranges from 0-1.5 wt %

Emotive are chosen from a group comprising fragrance, botanical extracts or mixtures thereof. The amount of emotive ranges from 0-1.5 wt %

pH regulators are chosen from a group comprising glycerol buffers, citrate buffers, borate buffers, phosphate buffers, or citric acid-phosphate buffers. The amount of pH regulator ranges from 0.5-2 wt %.

The essential feature of the present invention resides in the ratio of inorganic:organic structurant (1:4 to 1:1). The said ratio is required to achieve the following results:

· No or reduce bubble formation at the surface of bar, hence improve bar aesthetics.
· Balance moisture content to remove any cracking on surface
· Smooth and even surface
· Improved bar glide during application

Another embodiment of the present invention provides a process for improving surface finish of casted syndet bar by using unique combination of structurants, e.g., organic or natural structurants such as starches (like maize, tapioca, rice etc), inorganic natural structurants (kaolin, bentonite, fuller earth etc), inorganic synthetic structurants such as sodium/magnesium/calcium aluminium silicate, silica etc.

The process for the preparation of the syndet bar of the present invention comprises the steps of:
I. Mixing all fatty acids (4-12% w/w) , polymers (1-7% w/w) , waxes (5-16% w/w) , oil (0.5-3% w/w), emulsifier(1-10% w/w) in mixer at 65-750C
II. Post melting and mixing for sufficient time (20-30mins), add soap at 85-900C
III. Post soap melting add pH regulator (citric acid-0.2 -1.5% w/w) followed by surfactants (SCI 65%-40-55% w/w). Maintain temperature between 90-950C
IV. Addition of other additives like TiO2 (0.1-0.4%w/w), EDTA (0.025-0.1%w/w), on complete mixing of soap and surfactants
V. adding structurant (organic (1-8 %w/w)/Inorganic(2-8%w/w)) at high mixing speed followed by homogenization.
VI. add emollients(0.5-2%w/w) once all the powders are mixed into the mass properly.
VII. Mixing till achieve homogenous flow able mass, then cast into desired moulds for solidification

Preferred emulsifier used are AOS, SLES [1EO, 2EO], preferred pH regulator used are citiric acid, lactic acid, preferred surfactant used are SCI 65%, CAPB, preferred inorganic structurant used are aluminum silicate, sodium silicate and preferred organic structurant used is maize, preferred emollients used are glycerine, PEG-400.

The formulation of the present invention can be made and casted at temperature less than 1000C in the mixing system which is crutcher or any planetary mixer having homogenizer. Moreover, the composition of the present invention does not require any plodding to achieve bar. This is because it was tested through experimentation that similar results could be attained by only casting as illustrated in example 5.
The present invention is now described by way of non-limiting illustrating examples.
Example 1: (Working example) composition of syndet bar
S.No. Ingredient Wt / wt %
1 Surfactant 44
2 Free Fatty Acid/ plasticizer 6
3 Emulsifiers 3
4 Polymer 3
5 Soap 12
6 Binders 2
7 Oil 1
8 Emollient 1
9 Preservatives 0.01
10 Color / Fragrance / Emotive 1.09
11 pH Regulator 0.9
12 Wax 14
13 Minerals 2
14 Organic Structurant 4
15 Inorganic Structurant 6

Genreal working ratio of the organic and inorganic structurants in the composition disclosed above is 1:1.5.

Observation: Superior surface finish of the final soap bar was observed. No entrapment of air bubbles was noted.

Example 2: (Best Working example) composition of syndet bar
S.No. Ingredient Wt / wt %
1 Sodium Cocoyl Isethionate 44
2 Free Fatty Acid 6
3 CAPB/CMEA 3
4 PEG 4000 3
5 Soap 12
6 Water 2
7 Liquid paraffin Oil 1
8 Glycerin 1
9 Preservatives 0.01
10 Color / Fragrance / Emotive 1.09
11 pH Regulator 0.9
12 Hard Paraffin Wax 14
13 Talc 2
14 Organic Structurant(Starch) 4
15 Inorganic Structurant(Aluminium Silicate) 6

Specific working ratio of the organic and inorganic structurants in the composition disclosed above is 1:1.5.

Observation: The soap product with superior surface finish was obtained.

Example 3: (Non working example) - below the ratio 1:1

S.No. Ingredient Wt / wt %
1 Sodium Cocoyl Isethionate 30
2 Free Fatty Acid 3
3 CAPB/CMEA 1
4 PEG 4000 2
5 Soap 41.3
6 Water 2
7 Liquid paraffin Oil 1
8 Glycerin 2
9 Preservatives 0.01
10 Color / Fragrance / Emotive 1.09
11 pH Regulator 0.5
12 Hard Paraffin Wax 14
13 Talc 1
14 Organic Structurant(Starch) 1
15 Inorganic Structurant(Aluminium Silicate) 0.1

Specific non working ratio of the organic and inorganic structurants in the composition disclosed above is 0.1:1.0

Observation: According to table 3, it is demonstrated that the desired bar smoothness is not achieved outside the specific ratio of inorganic: organic structurants.

Example 4: (Non-working example) - Above the ratio 1:4

S.No. Ingredient Wt / wt %
1 Sodium Cocoyl Isethionate 25.9
2 Free Fatty Acid 3
3 CAPB/CMEA 1
4 PEG 4000 2
5 Soap 38
6 Water 2
7 Liquid paraffin Oil 1
8 Glycerin 2
9 Preservatives 0.01
10 Color / Fragrance / Emotive 1.09
11 pH Regulator 0.5
12 Hard Paraffin Wax 14
13 Talc 1
14 Organic Structurant(Starch) 8
15 Inorganic Structurant(Aluminium Silicate) 0.5

Specific non-working ratio of the organic and inorganic structurants in the composition disclosed above is 0.5:8.0

Observation. According to table 4, it is demonstrated that the desired bar smoothness is not achieved outside the specific ratio of inorganic: organic structurants. And process became very difficult due to sticky mass

Example 5: comparative example
Sample Surface Finish (Visual Rating by expert panels) Lather @ 30FH, ml Bar Hardness, mm MUSH, gm/50cm2 Sogginess @ 400C+75RH for 16hrs ROW , %
Higher the no, smoother the sample In terms of bar hardness , mm Sensory scores (1 to 5 ) Higher the no, stickier the sample
Working sample (A) 8 295 5.1-5.5 5-6 4.5-5.5 2 27.7
Non-working sample (B) 5 (very rough, not acceptable) 250 5.8-6.2 9-10 (very mushy, not acceptable) >13 (High sogginess, sample losses the shape. Not acceptable) 4 (very sticky, not acceptable) 30.2

Example 6: Demonstrates plodding not required since similar bar hardness is achieved with only casting

Conventionally opaque Syndet bars need to be plodded to obtain a surface finish and bar hardness. The present invention provides casted bars with same bar hardness as that of a plodded bar essentially without the additional requirement of plodding.

Result and observation:

Samples Bar Hardness , mm
Plodded Bar 2.9
Casted Bar 3.1
Example 7: Process of preparation of the syndet soap bar.
4-10 wt% of C16 to C18 fatty acid in the ratio of 1:1, waxes (11%), oil (4%) and emulsifier (5%) are mixed at 65°C for 25 mins. To this mixture 15 wt% soap is added at a temperature of 85°C. After soap is melted, pH regulator is added followed by 43wt% of surfactants and maintained at a temperature of 95°C. Other additives like TiO2, EDTA are added on complete mixing of soap and surfactants. To this mixture 4wt% inorganic and 4wt% organic structurants is added at high mixing speed followed by homogenization. 1wt% of emollients are added once all the components are mixed into the mass. The components are mixed until a homogeneous flowable mass is achieved. The mixture obtained is then cast into desirable moulds for solidification. ,CLAIMS:1. A syndet bar composition, comprising:

a. organic structurant;
b. natural or synthetic inorganic structurant; and
c. cosmetically acceptable excipients;

wherein the ratio of inorganic and organic stucturant ranges from 1:4 to 1:1.

2. The composition, as claimed in claim 1, wherein said organic structurant is selected from a group comprising Corn starch, potato starch, modified starch; fatty alcohols, high chain length fatty acids and combinations thereof.

3. The composition, as claimed in claim 1, wherein the amount of organic structurant ranges from 1-8 %w/w.

4. The composition, as claimed in claim 1, wherein the natural inorganic structurant is selected from a group comprising clay, kaolin, fuller’s earth, bentonite, talc and mixtures thereof.

5. The composition, as claimed in claim 1, wherein the synthetic inorganic structurant is selected from a group comprising of sodium/magnesium/calcium aluminium silicate, silica and mixture thereof.

6. The composition, as claimed in claim 1, wherein amount of said inorganic structurant ranges from 2-8%w/w.

7. A process for preparing the composition as claimed in claim 1 comprising steps of:
a) mixing fatty acid, polymer, wax, oil, emulsifier in mixer at 65-70oC;
b) adding soap post melting and mixing for 20-30 minutes at 85-90oC;;
c) adding and mixing pH regulators after melting followed by surfactants and adding other additives; post melting at 90-95oC;
d) adding structurant (organic (1-8 %w/w)/inorganic(2-8%w/w)) at high mixing speed followed by homogenization;
e) adding emollients once all the powders are mixed; and
f) homogenizing the mixture obtained in step e; and
g) casting the same into desired moulds for solidification;