Esterquat - A New Cationic Ingredient for

Transcription

1 Vol. 44. No. 4 ( 1995 ) 341 NEWS Esterquat - A New Cationic Ingredient for Cosmetic Formulations E. PRAT 1, J. KAHRE 2, and N. TOTANI 3 1 : Pulcra s. a. (Sector E. C./.42 Zona Franca Barcelona, Spain ) 2 : Henkel KGaA (40191 Duesseldorf, Germany ) 3 : Henkel Hakusui Corp. (9-3 Kitatone, Sowa-machi, Sashima-gun, Ibaraki-ken, ) We introduced a new type of cationic surfactant. The esterquats are safe and interesting raw materials with respect to their toxicity, dermatology, ecology and performance. Their efficacy is equivalent to other quaternary components like DSDMAC or CTAC. With its comparable applicational profile esterquats fit very well into modern concepts for cosmetics and toiletries. In the last years the behavior of chemical substances in the environment gained in - creasing importance for nearly all kinds of consumer products. Therefore the industry developed new types of raw materials to fulfill this demand of the market. One impor - tant point for cosmetic raw materials is the biodegradability under aerobic and anaerobic conditions. This is especially true for cationic conditioning agents, which are easi - ly removed from aerobic and anaerobic environments by adsorption to the sludge. A new class of cationic surfactants are the esterquats (Fig.-1). They are synthesized by esterification of triethanolamine with palm fatty acids and subsequent quaternization with dimethyl sulfate. Dehyquart F30 and Dehyquart F75, the esterquats of cosmetic grade with the trade name of Henkel 2-Hydroxyethylmethylbis(palmitoyloxy ethyl) 2-Hydroxyethylmethylbis( stearoyloxyethyl ) ammoniumethyl sulfate ammoniumethyl sulfate (INCI - declaration) QAC of Dehyquart F 30 (INCI - declaration ) QAC of Dehyquart F 75 Fig. -1 Esterquats-chemical structure. Corresponding author : N. TOTANI KGaA are both compounds in flake, that is, solvent-free and especially optimized according to the content of traces. They are compounds with fatty alcohol, which is usually included in formulations for rinses. The product data of Dehyquart F30 and F75 are shown below : Dehyquart F30 and Dehyquart F75 are both quaternized with dimethyl sulfate (DMS). For toxicological reasons traces of DMS should not be detectable in a cosmetic formulation. An analytical procedure for the detection of traces of DMS was devel - oped at Henkel. The esterquat-types contained in Dehyquart F30 and Dehyquart F75 are produced with a specially controlled process which allows to guarantee traces of DMS below 1 ppm. For the analytical deter - mination of DMS a small amount of esterquat is dissolved in hexane. With gas - chromatographic methods in an on-column procedure the DMS is separated and is detected by using a sulfur-specific detector. As expected for esterifications of trifunc - tional alcohols, esterquats are showing a distribution of mono-, di- and triesters (Table-2). Those values were obtained by HPLC on LICHROSORB D 101 column and RI detector. Due to the chemical structure of esterquats hydrolysis may occur. The stability of esterquats depending upon ph-value and 103

2 342 J. Jpn. Oil Chem. Soc. (YUKAGAKU) Table- 1 Esterquats-product data of Dehyquat F 30 and F 75. Table- 2 Distribution of esters in esterquats. analyzed by HPLC with RI detector storage time is shown in Fig.-2. The active substance, 2-hydroxyethylmethylbis ( palmitoyloxyethyl) ammonium methyl sulfate was determined according to ISO It was observed that the content of quaternaries and thus the functional activity in cosmetic preparations at ph 5 and below is practically constant. Quaternary ammonium components like hexadecyltrimethylammonium chloride (C- TAC) and dioctadecyldimethylammonium chloride (DSDMAC) which up to now are usually used in cosmetic formulations, are not biodegradable according to the guidelines of the OECD'). They are showing a lack of degradability especially under anaerobic conditions. In sewage treatment plants they are adsorbed on the sludge and precipitated. Esterquats are biodegradable Fig.- 2 Esterquats-storage stability at different ph. under aerobic and anaerobic conditions 2) The results of esterquat-degradation in the compounds Dehyquart F75 and F30 are shown in Table-3. In addition to the biodegradation the ecotoxicity of raw materials is an important point. Progress in development is extending investigations to more and more environmental criteria. Esterquats are modern products under this aspect too. The data of the ecotoxicity of the 2-hydroxyethylmethylbis(stearoyloxyethyl) ammonium methyl sulfate are shown in Table-4 compared to conventional quaternaries. Table- 3 Biodegradation of quaternary ingredients. 104

3 Vol. 44. No. 4 (1995) 343 Table- 4 Ecotoxicity of esterquats. Table- 5 Toxicological data of esterquats. For bacteria there is no difference between common quaternary compounds and esterquats. But for the aquatic toxicity esterquats have a great advantage. The toxicity against algae and fishes is clearly quite better than that of the common quaternaries. As demonstrated in Table-5 Dehyquart F 30 and Dehyquart F75 have the required toxicological profile for raw materials used in cosmetics. The Duhring chamber test demonstrates that esterquats are not provoking any dermatological reaction when applied in a concentration of 1 % active substance. This is comparable to mild cationic surfactants like quaternized collagen hydrolysates. Other cationics are showing a slight reaction. The dehyquart-types are not irritant to skin and eye-a further advantage compared to usual quaternaries. According to procedures described in the literature 3),4) all tests were done on hair Table- 6 Esterquats-test formulations. tresses. The formulations used are summarized in Table- 6. In rinses Dehyquart F30 and Dehyquart F75 reduce the wet combing forces of hair. We compared the efficacy of Dehyquart F-types with CTAC and DSDMAC. As 105

4 344 J. Jpn. Oil Chem. Soc. (YUKAGAKU) shown in Fig.-3 the reduction of wet combining forces leads to the same level of reduction as in the case of DSDMAC and CTAC. As well as the reduction of wet combing forces it is also important to consider the influence of esterquats on the dry combing forces. This is demonstrated in Fig.-4 in comparison to DSDMAC and CTAC. Again there is no significant difference. In combination with the dry combing forces one has to regard the electrostatic charge of hair. For a good styling and dressability of hair it is important to reduce the electrostatic charge. Esterquats are practically equivalent to DSDMAC and CTAC (Fig.-5). In addition to the objective test results the same formulations as before were compared in a half-head test. This test was done with 10 volunteers. The results demonstrate the comparison of Dehyquart F30 with CTAC (Fig.-6 and 7) and Dehyquart F75 with DS- DMAC (see Fig.-8 and 9). With respect to the behavior on wet hair, all products are equal in their rinse-off ability. Small differences are observed for the combability. The feel of wet hair seems to be somewhat different from that of DSDMAC and CTAC. This might be dependent on the type of hair and proper formulation. The same result is obtained for dry hair. Additionally we evaluated the dress- Fig.- 3 Esterquats-wet combing forces. Fig.- 6 Half head test result of Dehyquart F30 on wet hair. Fig.- 4 Esterquats-dry combing forces. Fig.- 7 Half head test result of Dehyquart F30 on dry hair. Fig.- 5 Esterquats-electrostatic charge. Fig.- 8 Half head test result of Dehyquart F75 on wet hair. 106

5 Vol. 44. No. 4 (1995) 345 Fig. - 9 Half head test result of Dehyquart F75 on dry hair. ability, the electrostatic charges and the gloss of the hair. This finally confirms the comparability in the performance of esterquats with quaternary components used usually. Sometimes DSDMAC may cause problems with respect to the thickening of formulations. Esterquats are easy to thicken in rinses with soy sterol (Generol 122(R)), polyglyceryl-3-diisostearate (Lameform TGI(R)) and lauryl polyglucose (Plantaren 1200(R) )5). (Received Sept. 20, 1994) References 1) Organization for Economic Cooperation and Development-OECD (1981), Paris. 2) R. Lagerman, S. Claney, D. Tanner, N. Johnston, B. Callian, and F. Friedli, J. Am. Oil Chem. Soc., 71, 97 (1994). 3) P. Busch, Arztliche Kosmetologie, 19, 270 (1989). 4) P. Busch, Th. Forster, H. Hensen, Th. Muller-Kirschbaum, H. Tesmann, Arztliche Kosmetologie, 20, 498 (1990). 5) Generol 122, Lameform TGI and plantaren 1200 are trademarks of Henkel KGaA. (Sector E. C./.42 Zona Franca Barcelona, Spain)