Patent Application
20150030553
The present invention relates to the use of isosorbide monoesters as thickeners.
In industry, thickeners are used to adjust the viscosity of products such as, for example, cosmetic, dermatological or pharmaceutical compositions, crop protection formulations, washing or cleaning compositions or paints or coatings in a targeted manner. Numerous thickeners which can be used for this purpose are known. These thickeners may have been produced synthetically, or they may be based on natural raw materials.
However, a disadvantage of the use of many synthetically produced thickeners, for example synthetic polymers, is that, frequently, their preparation is expensive and based on synthetic raw materials. In contrast, a disadvantage of the use of many thickeners based on natural raw materials is that the appearance of many products comprising such thickeners is in need of improvement.
Accordingly, it was an object of the invention to provide thickeners which do not have the disadvantages mentioned above or which improve these at least in part and which additionally have an advantageous thickener performance.
Surprisingly, it has now been found that this object is achieved by compounds of the formula (I)
in which
R is a straight-chain or branched saturated alkyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms or a straight-chain or branched mono- or polyunsaturated alkenyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms.
Accordingly, the invention provides the use of one or more compounds of the formula (I)
in which
R is a straight-chain or branched saturated alkyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms or a straight-chain or branched mono- or polyunsaturated alkenyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms as thickeners.
The compounds of the formula (I) are based on renewable raw materials such as, for example, on isosorbide, which can be obtained from sugar. They can be prepared in a simple manner by methods familiar to the person skilled in the art, for example by esterification of isosorbide with an acid component such as a carboxylic acid. The appearance of the products comprising the compounds of the formula (I) is not negatively affected by their presence. For example, compared to the use of xanthan gum which, as natural thickener, frequently yields products having a “brittle” or irregular or rough surface, using the compounds of the formula (I) it is possible to prepare thickened products having a smooth surface.
Compositions which are based at least in part on renewable raw materials and can be used as thickeners are already known.
WO 2010/108738 A2 (Evonik) describes formulations which are used to clean and care for human or animal body parts and comprise sorbitancarboxylic esters, where the carboxylic acid portion of the sorbitancarboxylic ester is derived from a carboxylic acid containing 6 to 10 carbon atoms and the sorbitancarboxylic esters have a hydroxyl value of more than 350, and the use of the sorbitancarboxylic esters mentioned as viscosity regulators, care active ingredient, foam booster or solubilizer in cleaning or care formulations.
Compounds of the formula (I) can be prepared, for example, by methods familiar to the person skilled in the art. For example, the compounds of the formula (I) can be prepared by esterification of isosorbide by customary methods known to the person skilled in the art, with both isosorbide for its part and also the acid components used for esterification once more being commercially available.
Preferably, the radical R in the one or more compounds of the formula (I) is a straight-chain saturated alkyl radical having 7 to 9 carbon atoms.
Particularly preferably, the radical R in the one or more compounds of the formula (I) is a straight-chain saturated alkyl radical having 7 carbon atoms.
According to the invention, the one or more compounds of the formula (I) can be used on their own or in compositions comprising one or more other substances as thickeners. Hereinbelow, these compositions are referred to as “compositions A”.
In a preferred embodiment of the invention, the compositions A comprise one or more compounds of the formula (I) and additionally one or more other substances selected from the group consisting of sorbitol, sorbitol esters (sorbitol esters can be mono-, di-, tri-, tetra-, penta- and/or hexaesters), sorbitan, sorbitan esters (sorbitan esters can be mono-, di-, tri- and/or tetraesters), isosorbide, isosorbide diesters and carboxylic acids. “Sorbitan” can be, for example, 1,4- or 1,5-sorbitan. Both the carboxylic acids themselves and the carboxylic acids on which the acid components of the esters mentioned are based correspond to the formula RCOOH in which R has the meaning given for formula (I) and is preferably a straight-chain saturated alkyl radical having 7 carbon atoms, i.e. the carboxylic acid RCOOH is preferably caprylic acid.
In a particularly preferred embodiment of the invention, the compositions A comprise one or more compounds of the formula (I) and additionally
From among these compositions, the compositions A just mentioned preferably comprise one or more compounds of the formula (I) and additionally
In a preferred embodiment of this embodiment of the invention, the compositions A just mentioned comprise either no carboxylic acid RCOOH or up to 0.1, preferably 0.001 to 0.05 and particularly preferably 0.002 to 0.01 part by weight of carboxylic acid RCOOH, where R has the meaning given for formula (I) and where the carboxylic acid is preferably caprylic acid, based on 1.0 part by weight of the one or more compounds of the formula (I) and preferably based on 1.0 part by weight of isosorbide monocaprylate.
In a further particularly preferred embodiment of the invention, the compositions A comprise one or more compounds of the formula (I) and one or more sorbitan esters of sorbitan and carboxylic acids RaCOOH, preferably selected from sorbitan esters of 1,4- and/or 1,5-sorbitan and carboxylic acids RaCOOH, where Ra is a straight-chain or branched saturated alkyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms or a straight-chain or branched mono- or polyunsaturated alkenyl group having 5 to 11, preferably 7 to 9 and particularly preferably 7 carbon atoms, and where the weight ratio of the one or more compounds of the formula (I) to the one or more sorbitan esters just mentioned is from 70:30 to 100:0, preferably from 80:20 to 100:0, particularly preferably from 90:10 to 100:0 and especially preferably from 95:5 to 100:0. The stated weight ratio of “100:0” means that in this particularly preferred embodiment of the invention, the compositions A just mentioned do not need to comprise any sorbitan ester.
From among the compositions A just mentioned, preference is given to those in which the one or more sorbitan esters of sorbitan and carboxylic acids RaCOOH are selected from sorbitan esters of sorbitan and caprylic acid and are preferably selected from sorbitan esters of 1,4- and/or 1,5-sorbitan and caprylic acid and the sorbitan ester is particularly preferably sorbitan monocaprylate.
In these compositions A, the hydroxyl value of the mixture of the one or more compounds of the formula (I) and the one or more (if present) sorbitan esters of sorbitan and carboxylic acids RaCOOH is preferably smaller than or equal to 320, particularly preferably smaller than or equal to 285, especially preferably smaller than or equal to 245 and most preferably smaller than or equal to 225.
In a further particularly preferred embodiment of the invention, the hydroxyl value of the mixture of the one or more compounds of the formula (I) and the one or more compounds selected from the group consisting of sorbitol, sorbitol esters, sorbitan, sorbitan esters, isosorbide, isosorbide diesters and carboxylic acids in the compositions A is smaller than or equal to 320, preferably smaller than or equal to 285, particularly preferably smaller than or equal to 245 and especially preferably smaller than or equal to 225.
In a further particularly preferred embodiment of the invention, the compositions A do not comprise any compounds selected from sorbitol and sorbitol esters.
In a further particularly preferred embodiment of the invention, the compositions A do not comprise any compounds selected from sorbitan and sorbitan esters.
If the compositions A do comprise one or more compounds selected from the group consisting of sorbitol and sorbitol esters (where the carboxylic acid on which the acid component of these esters is based is preferably caprylic acid), these compounds together are preferably present in the compositions A in an amount smaller than or equal to 5.0% by weight, particularly preferably in an amount smaller than or equal to 3.0% by weight, especially preferably in an amount smaller than or equal to 1.0% by weight and most preferably in an amount smaller than or equal to 0.5% by weight, the stated % by weight in each case being based on the total weight of the finished compositions A.
If the compositions A do comprise one or more compounds selected from the group consisting of sorbitan and sorbitan esters (where the carboxylic acid on which the acid component of these esters is based is preferably caprylic acid), these compounds together are preferably present in the compositions A in an amount smaller than or equal to 20.0% by weight, particularly preferably in an amount smaller than or equal to 10.0% by weight, especially preferably in an amount smaller than or equal to 5.0% by weight and most preferably in an amount smaller than or equal to 1.0% by weight, the stated % by weight in each case being based on the total weight of the finished compositions A.
In a further particularly preferred embodiment of the invention, the compositions A comprise the one or more compounds of the formula (I) in amounts of at least 30% by weight, preferably in amounts of at least 50% by weight and particularly preferably in amounts of at least 60% by weight, in each case based on the total weight of the finished compositions A.
The hydroxyl value of a substance is to be understood as meaning that amount of KOH in mg equivalent to the amount of acetic acid bound during the acetylation of 1 g of substance.
Suitable determination methods for determining the hydroxyl value are, for example, DGF C-V 17 a (53), Ph. Eur. 2.5.3 Method A and DIN 53240.
In the context of the present invention, the hydroxyl values are determined analogously to DIN 53240-2. Here, the following procedure is adopted: 1 g, accurate to 0.1 mg, of the homogenized sample to be measured is weighed out. 20.00 ml of acetylation mixture (acetylation mixture: 50 ml of acetic anhydride are stirred into 1 liter of pyridine) are added. The sample is dissolved completely in the acetylation mixture, if required with stirring and heating. 5 ml of catalyst solution (catalyst solution: 2 g of 4-dimethylaminopyridine are dissolved in 100 ml of pyridine) are added. The reaction vessel is closed and placed into the water bath, preheated to 55° C., for 10 minutes, with mixing. 10 ml of fully deionized water are then added to the reaction solution, the reaction vessel is closed again and the mixture is once more allowed to react in the water bath with shaking for 10 minutes. The sample is cooled to room temperature (25° C.). 50 ml of 2-propanol and 2 drops of phenolphthalein are then added. This solution is titrated with aqueous sodium hydroxide solution (aqueous sodium hydroxide solution c=0.5 mol/l) (Va). Under identical conditions, but without any sample added, the efficacy of the acetylation mixture is determined (Vb).
From the aqueous sodium hydroxide solution consumed in the determination of the efficacy and the titration of the sample, the hydroxyl value (OHV) is calculated using the following formula:
OHV=hydroxyl value in mg KOH/g substance
Va=aqueous sodium hydroxide solution consumed in ml during the titration of the sample
Vb=aqueous sodium hydroxide solution consumed in ml during the titration of the efficacy
c=molar concentration of the aqueous sodium hydroxide solution in mol/l
t=titer of the aqueous sodium hydroxide solution
M=molar mass of KOH=56.11 g/mol
E=sample weighed out in g
(Vb−Va) is that amount of aqueous sodium hydroxide solution used in ml, which is equivalent to the amount of acetic acid bound during the above-described acetylation of the sample to be measured.
Hereinbelow, the method just described for determining the hydroxyl value is referred to as “method OHV-A”.
Preferably, the use according to the invention is in cosmetic, dermatological or pharmaceutical compositions, in crop protection formulations, in washing or cleaning compositions or in paints or coatings. The crop protection compositions comprise one or more pesticides.
The cosmetic, dermatological or pharmaceutical compositions, the crop protection formulations, the washing or cleaning compositions or the paints or coatings comprise the one or more compounds of the formula (I) preferably in amounts of from 0.01 to 10.0% by weight, particularly preferably in amounts of from 0.1 to 5.0% by weight and especially preferably in amounts of from 0.2 to 3.0% by weight, in each case based on the total weight of the finished cosmetic, dermatological or pharmaceutical compositions, crop protection formulations, washing or cleaning compositions or paints or coatings.
The cosmetic, dermatological or pharmaceutical compositions, the crop protection formulations, the washing or cleaning compositions or the paints or coatings have viscosities preferably in the range from 50 to 200 000 mPa·s, particularly preferably in the range from 500 to 100 000 mPa·s, especially preferably in the range from 2 000 to 50 000 mPa·s and most preferably in the range from 5 000 to 30 000 mPa·s (20° C., Brookfield RVT, RV spindle set; 20 revolutions per minute).
The cosmetic, dermatological or pharmaceutical compositions are preferably present in the form of fluids, gels, foams, sprays, lotions or creams.
The cosmetic, dermatological or pharmaceutical compositions, the crop protection formulations, the washing or cleaning compositions or the paints or coatings are preferably formulated on an aqueous or aqueous-alcoholic basis or are present as emulsions or dispersions. Particularly preferably, they are present as emulsions, and especially preferably they are present as oil-in-water emulsions.
As further auxiliaries and additives, the cosmetic, dermatological or pharmaceutical compositions, the crop protection formulations, the washing or cleaning compositions or the paints or coatings may comprise all substances customarily used for the application in question, for example oils, waxes, emulsifiers, coemulsifiers, dispersants, surfactants, defoamers, solubilizers, electrolytes, hydroxy acids, stabilizers, polymers, film formers, further thickeners (different from the compounds of the formula (I)), gelling agents, superfattening agents, refattening agents, antimicrobially active compounds, biogenic active compounds, astringents, active substances, deodorizing substances, sun protection filters, antioxidants, oxidants, humectants, solvents, colorants, pigments, pearlizing agents, fragrances, opacifiers and/or silicones.
The cosmetic, dermatological or pharmaceutical compositions, the crop protection formulations, the washing or cleaning compositions or the paints or coatings have a pH of preferably from 2 to 11, particularly preferably from 4.5 to 8.5 and especially preferably from 5.5 to 6.5.
The examples and applications which follow are intended to illustrate the invention in more detail, without, however, limiting it. All percentages are % by weight, unless explicitly stated otherwise.
Thickener performance was measured under the following conditions: Brookfield RVT; 20° C.; RV spindle set; 20 revolutions per minute
In a stirred apparatus with distillation head, 190.0 g (1.3 mol) of isosorbide (“Sorbon” from Ecogreen Oleochemicals) and 187.5 g (1.3 mol) of octanoic acid (caprylic acid) are initially charged at 80° C. together with 0.38 g of aqueous sodium hydroxide solution (18% by weight strength, aqueous) as catalyst. With stirring and under a flow of nitrogen (10-12 liters per hour), the reaction mixture is initially heated to 180° C., where the water of reaction begins to distill off. The reaction mixture is then heated to 190° C. over a period of 1 hour and to 210° C. over a further 2 hours. After 210° C. is reached, the esterification is continued until an acid value of <1 mg KOH/g is reached. This gives 345.7 g of amber isosorbide caprylate (97% of theory). The pH (5% by weight in ethanol/water 1:1) is 5.9. The pH was measured according to DIN EN 1262.
Further analytical characteristics of the isosorbide caprylate:
The isosorbide caprylate has the following composition:
Hereinbelow, this composition is referred to as “isosorbide caprylate 1”
Using Genapol® LRO (sodium laureth-2 sulfate, 27% by weight in water) and Genagen® CAB 818 (cocamidopropyl betaine, 30% by weight in water) and additionally water, a 15% by weight mixture in water comprising the two surfactants in a weight ratio of 8:2 (hereinbelow referred to as “mixture 1”) is obtained. Various substances were added to this mixture 1, and the viscosity of the resulting compositions was determined. The results are shown in table 1 below.
Various amounts of isosorbide caprylate 1 were added to mixture 1, and the viscosity of the resulting compositions was determined. The results are shown in table 2 below.
It is evident from the results listed in tables 1 and 2 that isosorbide caprylate 1 has a thickening effect in aqueous surfactant systems.
Using Genapol® LRO (sodium laureth-2 sulfate, 27% by weight in water) and Genagen® KB (cocobetain, 30% by weight in water) and additionally water, a 15% by weight mixture in water comprising the two surfactants in a weight ratio of 8:2 (hereinbelow referred to as “mixture 2”) is obtained. Various substances were added to this mixture 2, and the viscosity of the resulting compositions was determined. The results are shown in table 3 below.
Various amounts of isosorbide caprylate 1 were added to mixture 2, and the viscosity of the resulting compositions was determined. The results are shown in table 4 below.
It is evident from the results listed in tables 3 and 4 that isosorbide caprylate 1 has a thickening effect in aqueous surfactant systems.
An emulsion as indicated in table 5 below was prepared, and various concentrations of isosorbide caprylate 1 were added. The viscosities of the resulting emulsions were determined. The results are shown in table 5 below.
Preparation:
It is evident from the results listed in table 5 that isosorbide caprylate 1 has a thickening effect in emulsions.
The thickener performance of isosorbide caprylate 1 in mixture 2 was compared, firstly, to a composition comprising 89.6% by weight of isosorbide dicaprylate and 9.4% by weight of isosorbide monocaprylate (remainder: 1% by weight) (hereinbelow referred to as “isosorbide dicaprylate”) and, secondly, to pure isosorbide. The results are shown in table 6.
As is evident from the results of table 6, the thickener performance of isosorbide is not worth mentioning, whereas isosorbide dicaprylate causes significant thickening.
However, as is also evident from the results of table 6, isosorbide caprylate 1 causes thickening comparable to that of isosorbide dicaprylate. If the thickener performance of isosorbide caprylate 1 were due only to the isosorbide dicaprylate comprised therein, the viscosity when using isosorbide caprylate 1 would have to be markedly lower that when isosorbide dicaprylate is used, since isosorbide caprylate 1 comprises only 30.6% by weight of isosorbide dicaprylate. Since the thickener performance of the isosorbide present in isosorbide caprylate 1 (as already mentioned above) is not worth mentioning and the possible thickening by the caprylic acid present in isosorbide caprylate 1 is negligible because of its small amount, but the thickener performance of isosorbide caprylate 1 is nevertheless comparable to the thickener performance of isosorbide dicaprylate, the compound isosorbide monocaprylate present in isosorbide caprylate 1 must have a significant thickener performance.
The use according to the invention can take place, for example, in the following formulations.
Preparation:
Preparation:
Preparation of formulation examples 3 and 4:
Half of the amount of water is initially charged and the components are stirred in in the same order as listed in the tables. The remaining amount of water is then added. This gives clear aqueous compositions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 109 437.0 | Aug 2011 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/003244 | 7/31/2012 | WO | 00 | 9/16/2014 |
