CZ3096A3 - Cube soap - Google Patents

Abstract

Soap bars comprising at least 5 wt% of a polyalkylene glycol and fatty acid in a ratio of 1:3 to 3:1 exhibit good lather volume and creaminess while maintaining acceptable mush and wear rates.

Description

The present invention relates to improved bar soaps and mentions a process for their manufacture.

In the present invention, the term cubes generally refers to solid three-dimensional bodies, whether in the form of elongated cubes, rounded, tablet cubes, sticks, blocks or other spatial shapes. In addition, the term bar soaps refers to bars containing fatty acid soaps or mixtures of fatty acid soaps with one or more synthetic detergent compositions.

BACKGROUND OF THE INVENTION

For a very long time, bar soaps have been made from fats by converting the triglyceride fat components into fatty acid salts and forming the soaps into bars. A general review can be found in Wollatt's The Manufacture of Soaps, Other Detergents and Glycerine, edited by John Wiley & Sons, 1985.

Generally soaps containing fatty acids with longer chains, particularly the less expensive C _IS and _Ig C soaps (as obtained from tallow and palm oils) provide in the finished soap bars and prevent or retard disintegration of the structure of the soap bar on exposure to water. More expensive shorter-chain soaps derived from lauric fat (i.e., lauric acid salts) and other soluble soaps (typically obtained from coconut oil and pale kernel oil) contribute to the foaming properties of the overall composition.

A general problem in forming bar soaps has been to find a balance between providing a structure (usually obtained from a cheaper tallow and / or palm component) and maintaining foaming capabilities (generally obtained from a more expensive coconut oil component) at a practical total cost. In typical commercial

- 2 preparations contain cube soaps of 90-50% fatty acid soaps obtained from tallow (ie non-lauric fats) and 10-50% fatty acid soaps obtained from coconuts (ie lauric fats). Especially in countries where tallow is acceptable to consumers, most commercial soap products contain 80% tallow and 20% coconut oil. In countries where tallow is not acceptable, it is replaced by other non-lauric oils and fats such as palm oil.

In addition to the soaps of the (per se) fatty acids themselves, the toilet soap bars may contain free fatty acids. The addition of free fatty acid is known as fat supersaturation and fat supersaturation to 5-10% of the amount of free fatty acid provides an abundant and creamy soap suds. Other supersaturants (see Wollatt, supra, p. 267) include citric acid and other acids that act to promote the formation of free fatty acids in the fat blend. A known drawback of supersaturated cubic products is a reduction in the physical stability of the bar, often manifested by increased softness upon prolonged exposure to water.

The conventional soap making process used in the production of toilet soaps is well documented in the literature. In principle, the procedure is as follows. In conventional wet soap production, fats, i.e., mixtures of tallow and coconut oil, are saponified in the presence of an alkaline agent (typically NaOH) to form fatty acids such as alkaline soaps and glycerol. Glycerol is extracted with brine to form a diluted fatty acid soap solution containing about 70% soap and 30% aqueous phase. This soap solution is dried, typically by heating in heat exchangers to about 130 ° C and vacuum drying to reduce the water content to about 12% and is completed by milling, kneading, and cubing.

A disadvantage of the fatty acid soap compositions is the coarse grain property, which is determined in many tests, as discussed below. Known solutions to the coarse grain problem include reducing the amount of soap present and bringing the mixture to equilibrium by so-called co-active surface

- 3 active substances. Megson et al. Discloses in US Patent 3576749 that the previously described supersaturation of toilet bar soaps increases their fineness, but the improvement is not considered as significant as the improvement obtained using co-active ingredients. As with supersaturants, the problem resulting from the presence of co-active agents is the loss of product structure in the resulting soap bars.

GB 2001098 (Colgate-Palmolive: 1978) discloses that supersaturated bar soaps may advantageously be prepared from mixtures containing primarily sodium soap of higher fatty acids and minor proportions of supersaturating higher fatty acids, water and at most 4%, preferably less, of polyethylene glycol polymer. high molecular weight. Obviously, the advantage of such a mixture is that the cubes provide a rich and creamy foam, but are solid and crack-resistant.

SUMMARY OF THE INVENTION

The authors found that bar soaps containing at least 5% relatively low molecular weight polyalkylene glycol and a fatty acid in a ratio of 1: 3 to 3: 1 exhibit surprisingly improved properties compared to bars containing the corresponding coconut-based soap.

In particular, the presence of both polyalkylene glycol and fatty acid significantly increases the volume of the foam and its creaminess while maintaining an acceptable rate of wear and softening. In addition, it is believed that certain processing difficulties associated with the presence of high molecular weight polyalkylene glycols can be avoided.

Thus, the present invention provides a bar soap comprising:

a) 44-86.5 wt. % fatty acid soap,

b) 5-30 wt. % polyalkylene glycol,

C) 2.5-20 wt. % C _with -C ₂₂ fatty acids and

d) 6-20 wt. % Of water wherein the ratio of polyalkylene glycol and C ₆ -C ₂₂ fatty acid is in the range of 1: 3 to 3: 1st

It is believed that the bars within the scope of the above formulation have improved skin softness and feel properties. Further details on preferred amounts and nature of the ingredients are provided below.

Soaps of fatty acids

Fatty acid soaps in an amount of 44-86.5 wt. % of the total product are an essential component of the present invention.

The average chain length of the fatty acid soaps falls within the range of C ₁₂ -C ₂₂ . Sources of such fatty acids include animal fats and / or fatty acids such as tallow and lard and their derived fatty acids, as well as vegetable oils, especially fats and / or fatty acids rich in palmitic and stearic acids such as palm oils and their shares.

If the fatty acids are derived from oil sources providing fatty acids with a high degree of unsaturation, such as soybean oil, sunflower oil, rice bran oil, flaxseed oil, rapeseed oil, peanut oil, sea oils and the like, Preferably, the stock oils are hardened or fractionated to obtain partially or fully hardened mixtures of fatty acids and / or stearins.

The bulk of the fats and fatty acids are preferably derived from tallow, except when nut oil or other vegetable substitutes are used for cultural reasons.

For economic reasons, it is preferred that the compositions according to

-5 of the present invention contained 10-50% lauric soaps, i.e. those having an average chain length less than _C16 . Most preferred fat blends comprise about 80% tallow and / or palm oil and about 20% coconut oil.

In preferred embodiments of the invention, the iodine value of the non-lauric soaps ranges from 10 to 55, and more preferably from 45 to 55.

Although simple oils, or rather fatty acid soaps derived therefrom, may be used as components of the compositions of the invention, the use of mixtures of two or more oils and / or mixtures of fatty acids is not excluded, and will be more common in practice.

Preferred amounts of soap relative to the product fall within the range of 50-80 wt. % per product and preferably 55-70%.

Poles of alkylene glycol

Polyalkylene glycol, the polymer, is in an amount of 5-30 wt. % relative to the product an essential component of the compositions of the present invention.

It is preferred that the alkylene glycol poles around be polyethylene glycol (PEG).

Lower amounts of said polymer do not provide the softness and / or skin feel benefits of the present invention, while at higher polymer levels the processability of the product is negatively affected. The preferred amount of polymer is about 7.5-25%, more preferably 9-20% of the product.

The PEG polymer typically has a molecular weight of less than 100,000 Daltons.

Polyethylene glycol preferably has a molecular weight in the range of 100-10000 Daltons, and preferably 400-5000 Daltons. The preferred PEG is miscible with water. PEG polymers with molecular weights above 10,000 are significantly less water soluble and form liquids of increasing viscosity above their melting points. This leads to processing difficulties. Although it is contemplated that the products may be prepared by dry blending high molecular weight PEG and dry soap base, this process may not provide the molecular level blending that is considered necessary to achieve the desired properties. The advantage of low molecular weight PEG is that they can be added as molten liquids or as low viscosity aqueous solutions. The addition of PEG may be carried out at any stage of soap making, including addition to dried soap, or wet soap prior to drying.

Supersaturants

Fatty acid, in an amount of 2.5-20% by weight relative to the product, is an essential component of the compositions of the present invention.

This amount of free fatty acid can be achieved by adding free fatty acids alone (per se), or by adding a non-fatty acid supersaturant and protonating the fatty acid soap portion to form the free fatty acid.

Suitable fatty acid supersaturants include tallow, coconut, palm and palm kernel fatty acids. Other fatty acids may be used although low melting point fatty acids, particularly lauric, are preferred for ease of processing. The preferred amount of fatty acid is 5-15%, more preferably about 10% relative to the product.

As mentioned above, the free fatty acids may be added by themselves or generated in situ by the addition of a non-fatty acid supersaturant such as inorganic or organic acids, preferably citric acid.

In addition to supersaturants, the compositions of the present invention may contain one or more plasticizers preferably selected from the group consisting of long-chain aliphatic alcohols, paraffin waxes, glycerol, monoglycerides, and mixtures thereof.

Synthetic active substances

In particular embodiments of the invention, the composition further comprises at least one synthetic anionic active agent in an amount not exceeding 20 wt. % and preferably in an amount not exceeding 10 wt. % relative to the product.

The synthetic anionic substance is preferably selected from the group consisting of: alkyl sulfates, alkyl ether sulfates, α-olefin sulfonates, long aliphatic isethionates, alkyl glyceryl ether sulfonates, mono-alkyl glyceryl sulfates, alkyl sarcosinates, alkyl taurides, alkylsulfosuccinates, alkylsulfosuccinates, alkylsulfosuccinates, alkylsulfosuccinates. Preferred among the anionic active ingredients are sodium lauryl ether sulfate (SLES), α-olefin sulfonates and sodium long-chain aliphatic isethionates. Sodium lauryl ether sulfate (SLES) and long-chain aliphatic sodium isethionates are particularly preferred.

In certain embodiments of the invention, the composition will further comprise a synergistic finer.

The synergistic fineness-active active substance will preferably be selected from the group consisting of nonionic surfactants, amphoteric surfactants and mixtures thereof. The synergistic fineness-active agent should be present in an amount of at least 5 wt. % of the total amount of active substance. Particularly preferred compositions contain from 5-25 wt. %, preferably 8-20% and even more preferably 9-18 wt. % synergistic active ingredient.

Suitable nonionic surfactants include: polyethoxylated alcohols, polyethoxylated alkylphenols, alkylpolyglycosides,

- 8 sorbitan esters, polysorbates, alkanolamides, poloxamers and mixtures thereof.

Of the nonionic surfactants, polyethoxylated alcohols, especially alkyl ethoxylates, are preferred. Preferred alkyl ethoxylates have an average alkyl chain length of 10-25 carbon atoms and an average ethoxylation range of 3-250 units.

Suitable amphoteric surfactants include: amine oxides. aminimides, betaines, amidobetaines and sulfobetaines and mixtures thereof. Coconut amidopropylbetaines and tegobetaines are particularly preferred due to the low possible content of the nitrosamine precursor.

Water content

In embodiments of the present invention, the total water content of the soap bar ranges from 6 to 20 wt. % relative to the soap bar.

The water content is preferably in the range of 8 to 17 wt. % and most preferably is 9-15 wt. %. The most preferred amount of water in the final bar is the normal water content of soap bars (about 12% relative to the bar), as conventional dryers can be used to achieve this level.

Electrolyte content

The electrolyte content of the cubes may vary. In practice, the electrolyte level will be between 0 and 1.5% relative to the product. All or some of the electrolyte may be a residue of the saponification procedures typically used in soap making, as is known in the art. It is also known that the amount of electrolyte may have some slight effect on the possible hardness of the product. These variations modify the hardness of the soap bars and can be used to control the final hardness within production limits. It is preferred that the electrolyte content is between 0.2-1.5 wt. % relative to the product.

The preferred electrolyte is sodium chloride in an amount of 0.2 to 0.8%.

Other electrolytes may be used either alone or in a mixture. Alternative preferred electrolytes include sodium sulfate and sodium carbonate.

Smaller folders

In addition to the basic and optional ingredients listed above, the compositions of the present invention may comprise one or more of the following optional ingredients: preservatives, perfumes, colorants, opacifiers and optical brighteners, humectants, emollients, germicides and other therapeutic ingredients.

Typical preservatives include those that completely suppress or reduce the unwanted catalytic effects of heavy metals, particularly iron and media. Preferably, they contain organic sequestrants such as EDTA or NTA. However, it is known that high amounts of EDTA can form colored complexes with iron and it is therefore customary to use EHDP (ethane-1-hydroxy-1,1-diphosphonic acid) in admixture with EDTA. The preferred amount of preservatives is generally in the range of 0.01 to 0.1 wt. % relative to the product.

Typical opacifying agents include titanium dioxide, preferably in an amount of about 0.2-0.4 wt. % relative to the product.

Typical emollients and / or wetting agents are selected from the group consisting of stearyl alcohol, glyceryl monolaurate, glyceryl monoricinoleate, glyceryl monostearate, propane-1,2-diol, butane-1,3-diol, docosane-1,2-diol, mink oil. , cetyl alcohol, isopropyl isostearate, stearic acid, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecan-2-ol, isocetyl alcohol, eicosanyl alcohol, behenyl alcohol, dimethylsilicate sulfate, n-ethyl palmitate, cetyl palmitate isopropyl stearate, butyl stearate, polyethylene glycol, triethylene glycol, lanolin, coconut butter, corn oil, cottonseed oil, tallow, lard, olive oil,

- 10 palm kernel oil, rapeseed oil, safflower oil, soybean oil, sunflower seed oil, sesame seed oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohols, mineral oil, butyl myristate, isostearic acid , palmitic acid, isopropyl oleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate, and mixtures thereof.

A preferred electrolyte that can be added to the compositions of the invention is sodium isethionate itself, preferably unsubstituted. This may be present as 0.1 to 50% of the composition, more preferably 0.5 to 25% and more preferably 2 to about 15% by weight.

For a better understanding of the present invention, it will be further illustrated by way of non-limiting examples.

DETAILED DESCRIPTION OF THE INVENTION

Examples 1 to 7

The following materials were used to prepare the products of the present invention with the formulations listed in Table 1 below:

TS: tallow fatty acid soaps having an iodine value of 46 (manufactured at home), calculated as tallow / coconut ratio,

CS: unhardened coconut fatty acid soap: quantities calculated as the ratio of tallow to coconut,

CA: coconut fatty acid; supersaturant: addition calculated by appearance to total fatty substance,

ST: stearic acid; supersaturant: addition calculated by appearance to total fatty substance,

- 11 PA: polyethylene glycol, molecular weight 600: addition, calculated in terms of appearance, of the total fatty substance,

PB: polyethylene glycol, molecular weight 4000: addition calculated by appearance to total fatty substance,

The formulations listed in Table 1 were prepared as follows:

(a) pure soap (free of admixtures) has been prepared containing tallow soap (TS) and coconut soap (CS) at 85 ° C;

b) the product of step (a) is combined with PEG (PA or PB) and supersaturants (CA or ST),

c) drying the product of step (b) and adding perfume and opacifying agents using a conventional belt mixer,

d) the coke product (c) was ground, kneaded and compressed into cubes using conventional equipment.

Alternatively, the products may be prepared by adding a mixture of PEG (PA or PB) and supersaturating agents (CA or ST) to the dried soap balls in a suitable mixer, eg a grinder mixer or a Z-blade mixer.

Products are evaluated for foam volume (measurement and estimation), creaminess (estimation), craziness and wear.

The foam volume was determined by a hand wash method that closely resembles a normal drinking habit. 20 unqualified volunteers were used in the test. Each volunteer put on a pair of surgical gloves and soaped the cube in still water at 30 ° C. The volume of foam produced was measured by dipping the volunteer's hands under a calibrated collection funnel.

Foam volume (LVE) and creaminess were also estimated at relative size.

Softening was determined by immersing portions of the weighed bar in distilled water at 20 ° C for 2 hours based on an increase in the recorded weight. The softening value is an increase in weight to 50 cm ^{2 of the} softened surface.

The wear was determined as a percentage weight loss of the bar due to a controlled washing process. The volunteer washed the pre-weighed dice using the method described above, with each dice being washed by each volunteer for 4 days each day. The cubes were then allowed to dry for 24 hours and then reweighed. The weight difference is expressed as a percentage of wear rate.

Example 1 is a comparative example using conventional 80/20 soap.

From the above results, it is apparent that supersaturation per se (per se, Example 7) had no significant effect on creaminess, foam volume or wear. Stubbornness increases so. as expected.

Examples 2 and 4 show the addition of PEG to conventional 80/20 soap. The wear rate increases and there is no significant change in foam volume or creaminess.

Examples 3, 5 and 6 show the benefits of adding both PEG and fatty acids as a supersaturant. In each case, the foam volume and creaminess were significantly increased while maintaining acceptable lubricity and wear rate.

- 13 Table 1

example 1 2 3 4 5 6 7 TS 80 80 80 80 80 80 80 CS 20 May 20 May 20 May 20 May 20 May 20 May 20 May CA - - 7.5% - 7.5% - 5,0 ° o ST - - - - - 7.5 - BYE - 10% 10% - - - - PB - - - 10% 10% 10% - perfume 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (%) water 12 12.5 13.2 12.8 11.8 11.0 10 (%) % wear 23.0 34.0 27.8 29.1 21.4 17.9 21.3 cunning 9.2 17.0 13.0 12.1 11.1 12.4 12.7 LVM 33.0 35.0 51.2 33.0 48.1 41.2 30.1 LVE 0.87 0.93 1,23 0.87 1.16 0.98 0.87 CR 0.96 0.97 1.10 0.93 1,02 - 0.97

Examples 8 to 19

The following substances were used to prepare the products of this invention with the formulations listed in Tables 2 to 5.

soap: 80/20 tallow / unhardened coconut fatty acid soap

CA: coconut fatty acid; supersaturant

PEG: polyethylene having the molecular weight given in Tables 2-5

- 14 The compositions in Tables 2 to 4 were prepared as follows:

(a) pure soap (free of admixtures) has been prepared containing tallow soap (TS) and coconut soap (CS) at 85 ° C;

b) PEG and CA were added to the product of step (a) and the mixture was dried either by air drying (air) or using a Mazzoni vacuum dryer (M)

c) the product of step (b) was then mixed with smaller components and the resulting product was milled, kneaded and compressed.

The workability of the products in Table 2 was evaluated. The workability was evaluated by the ability of the processing equipment to successfully transport the product from the comminution to the pressing equipment.

In Tables:

DB indicates that there has been a slight blockage of the press which can be overcome by the use of a lubricant.

OK due to kneading shows acceptable hardness of the balls.

- 15 Table 2

example no. component 8 9 mass 10 % 11 soap 70.1 68.7 70.4 75.7 CA 7.6 7.3 7.6 5.2 PEG 600 10.0 - - - PEG 4000 - 9.9 - - PEG 10,000 - - 10.0 - PEG 1000,000 - - - 5.2 salt 0.5 0.5 0.5 0.5 perfume 1.0 1.0 1.0 1.0 water and smaller components up to 100% PEG: CA ratio 1,3: 1 1.4: 1 1,3: 1 1 - 1 processing method M air M air grinding Okay Okay Okay No kneading Okay Okay Okay - pressing DB Okay Okay -

The results show that the product prepared with high molecular weight PEG is not comminutable.

In Examples 12-14, the effect of the amount of PEG on processability was evaluated

Table 3

example no. component 12 13 14 weight% soap 76.0 76.4 71.8 CA 5.2 5.3 5.0 PEG 600 5.2 - - PEG 4000 - 5.3 10.4 salt 0.5 0.6 0.5 water / perfume / minor ingredients up to 100% PEG: CA ratio 1 - 1 1 - 1 2 - 1 processing method air air air grinding Okay Okay Okay kneading Okay Okay Okay pressing Okay Okay Okay

Working up the mixture of each example was found acceptable.

In Examples 15-19, the effect of the amount of CA on processable was tested; r

Table 4

example no. component 16 17 18 19 weight% soap 75.2 71.8 70.2 66.5 70.4 PEG 4000 9.8 10.4 10.2 9.5 10.0 perfume 1.0 1.0 1.0 1.0 water and smaller components up to 100% PEG: CA ratio - 2.1: 1 1.4: 1 1 - 1 1 - 1 processing method air air air M M grinding Okay Okay Okay Okay Okay kneading cracked Okay Okay Okay Okay pressing cracked Okay Okay DB DB

While the processability of Examples 16 and 17 was acceptable, it was found that the compositions of Examples 18 and 19 suffered from both softness and tack problems which resulted in blockage of the die punch. However, difficulties have been overcome by applying glidant to both sides of the press.

Example 15, which did not contain any fatty acid, suffered seriously.

process difficulties, especially in the kneading and molding phases and arise from the.

exhibited severe cracking and surface damage even when a glidant was applied to the die punch surfaces.

Claims (9)

PATENT CLAIMS Cube soap, characterized in that it contains: (a) 44 to 86.5% by weight of a fatty acid soap; b) 5 to 30% by weight of polyalkylene glycol c) 2.5 to 20% by weight of a C ₆ to C ₈ fatty acid; and d) 6 to 20% by weight of water; wherein the ratio of the polyalkylene glycol to the C ₆ -C ₈ fatty acid is in the range of 1: 3 to 3: 1 and the polyalkylene glycol has a molecular weight of less than 100,000 Daltons. A bar soap according to claim 1, wherein the polyalkylene glycol is polyethylene glycol. A bar soap according to claim 1, wherein the fatty acid soap contains 10 to 50% lauric soaps. A bar soap according to claim 1, wherein the iodine value of the non-lauric soaps is in the range of 10 to 55. A bar soap according to claim 1, wherein the polyalkylene glycol is present in an amount of from 7.5 to 25% by weight. The bar soap of claim 1, further comprising a synthetic anionic active ingredient in an amount of at most 20% by weight. A bar soap according to claim 1, further comprising a synergistic fineness active. - 19 8. A bar soap according to claim 1, further comprising an electrolyte in an amount of 0.2 to 1.5% by weight. 9. A bar soap according to claim 1, wherein the free fatty acid content is obtained by adding the free fatty acid per se or by forming the free fatty acid under in situ conditions.