SK996A3 - A particulate 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

Technical field

The invention relates to improved lump soaps and to a process for making such soaps.

In the context of the present invention, the term piece generally refers to a rigid body, either in the form of a cube, tablet, rod, block or other three-dimensional shape. In addition, the term "block soap" refers to pieces containing fatty acid soaps or mixtures of fatty acid soaps with one or more surfactants.

BACKGROUND OF THE INVENTION

For many years, lump soaps have been made from fats by converting the triglyceride fat components into fatty acid salts and forming the soaps into lumps. A general review can be found in Voollatt: The Manufacture of Soaps, Other Detergents and Glycerin, John Viley & Sons, 1985.

Generally, the longer chains of fatty acid soaps, especially the less expensive C18 and C18 soaps (which are obtained from tallow and palm oil), provide a structure for terminal soap bars and prevent or retard the breakdown of the soap bar when exposed to water. More expensive, shorter-chain soaps obtained from lauryl fat (i.e. lauric acid salts) and other soluble soaps (typically obtained from coconut and palm kernel oil) contribute to the foaming properties of the overall composition.

A general problem in preparing soap bars was to strike a balance between providing a structure (generally obtained from a cheaper tallow / palm component) and maintaining foaming properties (generally obtained from a more expensive coconut oil component) at a practical overall cost.

In typical commercial preparations, the lump soaps contain from 90 to 50% by weight tallow fatty acid soaps (i.e., non-lauryl fats) and 10 to 50% by weight coconut fatty acid soaps (i.e., lauryl fats). Especially in countries where tallow is acceptable to consumers, most commercial soap formulations comprise 80% by weight of tallow and 20% by weight of coconut oil. In countries where tallow is unacceptable, tallow is replaced by other non-lauryl oils or fats such as palm oil.

In addition to the fatty acid soaps themselves, toilet soap contains free fatty acid. The addition of free fatty acid is known as superfatting, and a grease level of 5-10% by weight of free fatty acid is used to provide a rich creamy foam. Other lubricants (see Voollatt, cited above, page 267) include citric acid and other acids that act to promote the formation of free fatty acids in the fat blend. A known disadvantage of greased products in lump form is a reduction in the physical stability of the soap, often manifested by increased lubricity upon prolonged exposure to water.

A conventional method of making soap in an application for making soap is well described in the literature. In short, this method is as follows. In conventional wet soap production, fats such as tallow and coconut oil blends are saponified in the presence of an alkali (typically NaOH) to obtain fatty acids such as alkaline soaps and glycerin. The glycerin is extracted with brine to give a diluted fatty acid soap solution containing about 70% by weight soap and 30% by weight aqueous phase. This soap solution is dried, typically by heating in heat exchangers to about 130 ° C and vacuum drying to a water content of about 12% by weight, and is completed by milling, pelletizing and embossing into soap bars.

A drawback of fatty acid soap compositions is the roughness, a property that is determined by numerous tests, which will be described hereinafter. Known solutions to the roughness problem include reducing the level of soap present and replacing the supplement with so-called co-active ingredients. Megson et al., US 3576749 suggests that the grease as described above improves fineness, but the improvement is not considered as significant as the improvement obtained by using the co-active ingredients. As with the ointment reagents, the problem observed in the resulting soap bars due to the presence of the co-active ingredients is the loss of product structure.

GB 2001098 (Colgate-Palmolive: 1978) discloses that greased soap bars can be advantageously prepared from mixtures containing predominantly sodium soap of higher fatty acids and a minor proportion of greasy higher fatty acids, water and up to 4% by weight, preferably less, high molecular weight polyethylene glycol polymer. It is argued that the advantage of such a composition is that the soap gives a rich creamy foam, but is strong and crack resistant.

SUMMARY OF THE INVENTION

Lump soaps containing at least 5% by weight of a relatively low molecular weight polyalkylene glycol and a fatty acid in a ratio of 1: 3 to 3: 1 have been found to exhibit surprisingly improved properties compared to soaps having an equivalent coconut-based soap content.

In particular, the presence of both polyalkylene glycol and fatty acid significantly increases both foam volume and creaminess while maintaining acceptable lubricity and wear rate. In addition, it is believed that this avoids some processing difficulties associated with the presence of high molecular weight polyalkylene glycols.

Accordingly, the present invention provides lump soap comprising:

a) 44 to 86.5% by weight of a fatty acid soap;

b) 5 to 30% by weight of a polyalkylene glycol;

c) 2.5 to 20% by weight of a C 1 -C 22 fatty acid; and

d) 6 to 20% by weight of water wherein the ratio of polyalkylene glycol to C 8 -C 22 fatty acid is in the range of 1: 3 to 3: 1.

It is believed that the soaps falling within the aforementioned composition space have improved skin softness and feel properties. Further details regarding the preferred levels of content and nature of the ingredients are provided below.

Fatty acid soaps

Fatty acid soaps having a level of 44-86.5% by weight in the product are an essential component of the present invention.

Preferably, the mean chain length falls within the range of ΐ2 ”^ 22. Sources of such fatty acids include animal fats / fatty acids, for example tallow and pork ointment, and fatty acids derived therefrom, as well as plant derived oils, especially fats / fatty acids rich in fat. palmitic acid and stearic acid such as palm oil and its fractions.

When fatty acids are obtained from oil sources, fatty acids with a high degree of unsaturation are provided, such as soybean oil, sunflower oil, rice bran oil, flaxseed oil, rapeseed oil, peanut oil, coconut oil and similarly, the oil feedstocks are preferably solidified or fractionated to provide partially or fully solidified mixtures of fatty acids and / or stearins.

Preferably, most of the fats and fatty acids are derived from tallow, except for nutritional reasons where nut oil or other plant substitute is used.

For reasons of economy, it is preferred that the compositions of the invention contain 10 to 50% by weight of lauryl soaps, i. those soaps having a medium chain length less than most preferred fatty compositions comprise about 80% by weight tallow and / or palm oil and about 20% by weight coconut oil.

In preferred embodiments of the invention, the iodine number of the non-lauryl soaps is in the range of from 10 to 55, and more preferably from 45 to 55.

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

Preferably the levels of soap content in the product fall within the range of 50 to 80% by weight in the product, more preferably 55 to 70% by weight.

polyalkylene

Polyalkylene glycol, a polymer having a level of 5 to 30% by weight in the product, is an essential component of the compositions of the present invention.

Preferably, the polyalkylene glycol is polyethylene glycol (PEG).

Lower levels of this polymer do not provide the benefits of the present invention in softness / feel on the skin, while higher levels of polymer adversely affect the processability of the product. Preferably, the polymer level is about 7.5 to 25% by weight, most preferably 9 to 20% by weight of the product.

Typically, the PEG has a molecular weight below 100,000.

Preferably, the polyethylene glycol has a molecular weight ranging from 100 to 10,000, and more preferably from 400 to 5,000. Preferred PEG-γ are water-soluble. PEGs with molecular weights above 10,000 are significantly less soluble in water and form quartz (high viscosity wastes above their melting point). This leads to processing difficulties. If it is considered that the products can be prepared by dry blending high PEGs molecular weight and dry soap base, this would not provide mixing at the molecular level that is considered necessary to achieve the desired properties.An advantage of low molecular weight PEGs is that they can be added as molten liquids or as viscous liquid solutions. The PEG may be at any step of the soap making process, including addition to dry soap or wet soap prior to drying.

Greasing agents

A fatty acid level of 2.5 to 20% by weight of the product is an essential component of the compositions of the present invention.

This level of free fatty acids can be obtained by adding free fatty acids alone or by adding a non-greasy acidic greasy reagent that protonates part of the fatty acid soaps present to form the free fatty acid.

Suitable fatty acid lubricating agents include tallow, palm and palm kernel fatty acids. Other fatty acids may also be used, although low melting point fatty acids, especially lauric acid, are preferred for ease of processing. Preferred levels of fatty acids are 5 to 15% by weight, most preferably about 10% by weight of the product. I

As noted above, the free fatty acids may be added alone or may be formed in situ by the addition of non-greasy acidic greasy reagents such as inorganic and organic acids, preferably citric acid. |

In addition to the lubricating agents, the compositions of the invention may include one or more plasticizers, preferably selected from the group consisting of fatty alcohols, paraffin waxes, glycerol, monoglycerides, and mixtures thereof.

Synthetic surfactants i

and

In particular embodiments of the invention, the composition further comprises at least one synthetic anionic surfactant at a level of no more than 20% by weight, preferably a level of no more than 10% by weight of the product.

Preferably, the synthetic anionic surfactant is selected from the group consisting of: alkyl sulfates, alkyl ether sulfates, alpha-olefin sulfonates, fatty isethionates, alkyl glyceryl ether sulfonates, mono-alkyl glyceryl sulfates, alkyl sarcosinates, alkyl taurides, alkyl sulfosuccinates, alkyl phosphates, and mixtures thereof. Among the anionic surfactants, sodium lauryl ether sulfate (SLES), alpha-olefin sulfonates and sodium fatty isethionates are preferred. Sodium lauryl ether sulfate (SLES) and sodium fatty isethionates are particularly preferred.

In some embodiments, the invention will further comprise a synergistic softener surfactant.

Preferably, the synergistic softener surfactant is selected from the group consisting of nonionic surfactants, amphoteric surfactants, and mixtures thereof. A synergistic softening surfactant should be present at a level of at least 5% by weight of the total active ingredient level. Particularly useful compositions contain 5 to 25% by weight, preferably 8 to 20% by weight, more preferably 9 to 18% by weight of the synergistic softener surfactant of the total active ingredients.

Suitable nonionic surfactants include: polyethoxylated alcohols, polyethoxylated alkylphenols, alkylpolyglycosides, sorbitan esters, polysorbates, alkanolamides, poloxamers, and mixtures thereof. Preferred among the nonionic surfactants are polyethoxylated alcohols, especially alkyl ethoxylates. Preferred alkyl ethoxylates have a mean chain length of 10 to 25 carbons and an average ethoxylate unit content of 3 to 250.

Suitable amphoteric surfactants include: aminooxides, aminoimides, betaines, amidobetaines and sulfobetaines and mixtures thereof. Cocoamidopropyl betaines and tegobetaines are particularly advantageous because of their low content of potential nitrosamine precursors.

Water content

In embodiments of the invention, the total water content of the soap bar should be in the range of 6 to 20% by weight of the soap bar.

Preferably, the water content falls within the range of 8 to 17% by weight and is most preferably 9 to 15% by weight. The most preferred level of water content in the final soap bar is that which is normal for soap bars (about 12% by weight of the soap bar), so conventional dryers can be used to achieve this level.

Electrolyte content

The electrolyte content of the soap bar may vary. In practice, the level of electrolyte content will be between 0 and 1.5% by weight of the product. Some or all of the electrolyte may be a residue of the saponification process typically used in soap making, as is known in the art. It is also known that the level of electrolyte content may have some slight effect on the final hardness of the product. These variations modify the hardness of the soap bar and can be used to control the final hardness within the desired limits. Preferably, the electrolyte content is between 0.2 and 1.5% by weight of the product.

A preferred electrolyte is sodium chloride at a level of 0.2 to 0.8% by weight. Other electrolytes may be used either alone or in admixture. Among the alternative electrolytes, sodium sulfate and sodium carbonate are preferred.

Minority ingredients

In addition to the essential and optional ingredients mentioned above, the compositions of the present invention may contain one or more of the following optional ingredients: preservatives, perfumes, paints, opacifiers and optical brighteners, humectants, emollients, germicides and other medical ingredients.

Typical preservatives include substances that interfere with or reduce the adverse catalytic effects of heavy metals, especially iron and copper. These substances preferably include organic sequestrants such as EDTA or NTA. However, it is known that high levels of EDTA may form colored complexes with iron and it is therefore common to use EHDP (ethane-1-hydroxy-1,1-diphosphonic acid) in admixture with EDTA. Preferred levels of preservatives are generally in the range of 0.01 to 0.1% by weight of the product.

Typical opacifiers include titanium dioxide, preferably having a level of about 0.2 to 0.4% by weight of the product.

Typical emollients / humectants 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, minic acid, isopropyl alcohol, cetyl alcohol, cetyl alcohol, cetyl alcohol, cetyl alcohol, cetyl alcohol, cetyl alcohol, stearic, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecan-2-ol, isocetyl alcohol, eicosanyl alcohol, behenyl alcohol, cetyl palmitate, silicone oils, such as dimethylpolysiloxyl stearate, isobutyl stearate, di-stearate; , triethylene glycol, lanolin, coconut butter, corn oil, cottonseed oil, tallow, pork oil, olive oil, palm kernel oil, rapeseed oil, safflower oil, soybean oil, sunflower oil, olive oil, sesame oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohols, kerosene, mineral mineral oils, 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 present invention is a simple isethionate, preferably unsubstituted. It may be present as 0.1 to 50% by weight of the composition, preferably 0.5 to 25% by weight, more preferably 2% to about 15% by weight.

DETAILED DESCRIPTION OF THE INVENTION

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

Examples 1 to 7

The following materials were used to prepare the products of the invention having the composition as shown in Table 1 below:

TS: tallow fatty acid soaps with iodine value (laboratory prepared), indicated by tallow: coconut ratio,

CS: coconut fatty acid soap: indicated values are tallow: coconut ratio,

CA: coconut fatty acid, greasy reagent:

an indication of the total grease additive,

ST: stearic acid, greasy reagent: indicated addition to total fatty material,

PA: polyethylene glycol, mol.wt. 600: indicated total grease additive,

PB: polyethylene glycol, mol.wt. 4000: indicated total grease additive.

Compositions as listed in Table 1 were prepared as follows:

(a) the soap itself was prepared including tallow soaps (TS) and coconut soaps (CS) at 85 ° C;

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

c) the product of step (b) is dried and perfume and opacifiers are added using a conventional tape mixer,

d) the product of step (c) is milled, pelletized and embossed into lump soaps using a conventional apparatus.

Alternatively, the products can be prepared by adding a mixture of PEG (PA or PB) and lubricating agents (CA or ST) to the dried soap flakes in a suitable mixer, for example a mill or a Z-knife mixer.

The products were evaluated in terms of foam volume (by measurement and estimation), creaminess (estimation), crease formation and wear.

Foam volume (LVM) was measured by a hand washing method that closely approximates normal consumer use. The test involves the use of 20 untrained volunteers. Each volunteer wears a pair of surgical gloves and foams a soap bar in standing water at 30 ° C. The volume of foam formed was measured by immersing the panelists' hands in a calibrated collection funnel.

Foam volume (LVE) and creaminess were also estimated by relative size. These values represent the order of increasing size with a higher score.

Lubricity was determined by dipping a weighed portion of soap in distilled water at 20 ° C for 2 hours, and weight gain was recorded. The lubricity value is an increase in weight per 50 cm @ 2 of greasy surface.

The wear was determined as a percentage of the weight loss of the soap as a result of the controlled washing procedure. Panelists used pre-weighed soaps using the prescribed procedure, soaps were used by panelists for four days. After this time, the soaps were allowed to dry for 24 hours and weighed again. The weight difference was expressed as a percentage of the wear rate.

Table 1

Example 1 2 3 4 5 6 7 TS 80 80 80 80 80 80 80 CS 20 20 20 20 20 20 20 CA - - 7,5% - 7,5% - 5,0% ST - - - - - 7,5% - PA - 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 10 (%) % wear 23.0 34.0 27.8 29.1 21.4 17.9 21.3 sliminess 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

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

From the above results, it can be seen that the grease alone (Example 7) does not have a significant effect on creaminess, foam volume or wear. Stubbornness is increasing as expected.

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

Examples 3, 5 and 6 show the usefulness of adding both PEG and fatty acid as a greasy reagent. In all cases, the foam volume and creaminess increased significantly while maintaining acceptable lubricity and wear rate.

Examples 8 to 19

The following materials were used to prepare the products of the invention having the composition as shown in Tables 2 to 5 below:

Soap: soaps of 80/20 tallow / non-hardened coconut fatty acids.

CA: coconut fatty acid, greasy reagent.

PEG: Polyethylene glycol with molecular weight shown in the tables.

Mixtures as listed in Tables 2 to 4 were prepared as follows:

(a) the soap itself has been prepared including tallow soaps and coconut soaps at 85 ° C;

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

c) the product of step (b) is mixed with minor components and the resulting product is ground, pelletized and embossed.

The products in Table 2 were evaluated for processability. Workability was evaluated by the ability of the processing equipment to satisfactorily transfer the product from the milling to the embossing equipment.

In tables:

DB indicates that there was a slight blockage of the punch of the punching device, which could be overcome by means of a lubricant.

OK with respect to pelletizing indicates that the hardness of the blocks was acceptable.

Table 2

Example # component 8 9 10 11 % by weight 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 10000 - - 10.0 - PEG 100000 - - - 5.2 salt 0.5 0.5 0.5 0.5 PERFUME 1.0 1.0 1.0 1.0 Water and minor components up to 100% by weight PEG: CA ratio 1.3: 1 1.4: 1 1.3: 1 1: 1 process processing M Air M Air milling OK OK OK well plodding OK OK OK - punching OK OK OK -

The results show that the product prepared with high molecular weight PEG could not be ground.

Examples 12-14 assessed the effect of PEG levels on processability.

Table 3

Example # component 12 13 14 % by 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 0.5 0.5 Water / Perfume / Minor zl. up to 1 ( 0% by weight Ľných PEG: CA ratio 1: 1 1: 1 2: 1 Method of processing Air Air Air milling OK OK OK plodding OK OK OK punching OK OK OK

It was found that processing of the mixtures of all examples was acceptable.

Examples 15-19 evaluated the effect of CA level on processability.

Table 4

Example # component 16 17 18 19 % by weight Soap 75.2 71.8 70.2 66.5 70.4 PEG 4000 9.8 10.4 10.2 9.5 10.0 CA 0 5.0 7.5 9.5 10.0 salt 0.5 0.5 0.5 0.5 0.5 Water / Perfume / Minor zl. up to 100% by weight PEG: CA ratio - 2.1: 1 1.4: 1 1: 1 1: 1 process processing Air Air Air M M milling OK OK OK OK OK plodding cracking OK OK OK OK punching cracking OK OK DB DB

While the processability of Examples 16 and 17 was acceptable, it was found that the mixtures of Examples 18 and 19 suffered from both fineness and tack problems, causing the punch blocking of the embossing device.

Example 15, which contained no fatty acid suffered from severe _t problems in processing, especially in the plodding and stamping stages, the resulting bars showing severe cracking and damage of • the surface even when the surfaces of the die equipment used razieceho lubricant.

Claims (9)

PATENT CLAIMS 1. Lump 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 a polyalkylene glycol; c) 2.5 to 20% by weight of a C8-C22 fatty acid; and d) 6 to 20% by weight of water and wherein the ratio of polyalkylene glycol to C 8 -C 22 fatty acid is in the range of 1: 3 to 3: 1 and the polyalkylene glycol has a molecular weight below 100,000. A block soap according to claim 1, characterized in that the polyalkylene glycol is polyethylene glycol. 3. A bar of soap according to claim 1, wherein the fatty acid soap comprises 10 to 50% by weight of lauryl soap. A soap bar according to claim 1, characterized in that the iodine number of the non-lauryl soap is in the range of 10 to 55. 5. A bar of soap according to claim 1, wherein the polyalkylene glycol is present at a level from 7.5 to 25% by weight. 6. A soap bar according to claim 1, further comprising a synthetic anionic surfactant having a level of no more than 20% by weight. 7. A soap bar according to claim 1, further comprising a synergistic softener surfactant. 8. A soap bar according to claim 1, further comprising an electrolyte with a level of from 0.2 to 1.5% by weight. A soap bar according to claim 1, characterized in that the free fatty acid content is obtained by adding the free fatty acid itself or by forming the free fatty acid in situ.