Stephan Hinterwaldner - Hinterwaldner Consulting & Partner, Germany Dr Urs Zimmerli - Polyga l AG, Switzerland Developments in guar derivatives and boric acid
Ever since the incl usion of boric acid and For most industries. however. the Guar derivatives sodium borates on the candidate list of reaction was quick or even pre-emptive Guar derivatives are commonly used in the Substances of Very High Concern (SVHC) and the presence of boric acid in many cosmetics industry as rheology modifiers, in June 2010 these substance have been consumer products has been limited or its stabi lisers or conditioning polyme rs. the subject of greater attention in a host use has been eli minated altogether - Traditionally, guar derivatives such as of industries. examples include toys, cigarette paper, hydroxypropyl guar and guar hydroxypropyl The current situation may be considered carpets and other textiles. But what were trimonium chloride contain boric acid a period of transition wherein the different the consequences in the cosmetics and borates. industries assess the risks associated with industry? The reason is two-fold. Firstly, borates boric acid and borates and policies are This article does not seek to provide have been used in the production of developed. There are certain oddities, such a complete overview on boric acid in these guar derivatives as processing aids, as the continued listing of boric acid and the cosmetics industry. Instead, the facilitating a speCific route of production. borates as a food additive up to a level of developments sha ll be illustrated on the Secondly, borates provide a very specific 0.4% in caviar in the EU (EC 1129/2011). case of guar derivatives. functiona li ty to guar gum and its derivatives. Guar market stabilises and globalises
In 2012 the guar market was strongly perturbed by a sudden surge in demand from the shale gas fracking industry. The agricultural production of guar, which is an annual crop, was not able to respond immediately to the change in consumption. Further, purchasing influenced by fear of a shortage and panic artificially increased demand for guar. This resulted in an imba lance of supply and demand and consequently in an unprecedented price spike. Throughout the cri sis, however, material was always available. At the end of 2012 the arrival of the new crop rebalanced markets to a significa ntly lower price level. The 2012 crop was larger than any crop before as significantly more farming area was dedicated to the cultivation of guar. Furthermore, guar growing has diversified geographically with new regions cultivating guar in Asia, Africa alternative to cotton and other crops. fertiliser of subsequent crop cycles. and the US. The supply of guar for The geographical spread of guar as All information currently available 2013 should exceed the dernand and an agricultural crop is an im portant indicates clearly that guar will be avai lable allow for the filling of the necessary contribution to a more sustainable in plenty, the rnarket wi ll be more stable buffers along the supply chai ns. agri cu lture, as the guar plant requires and although prices may result slightly Polygal AG expects prices to very little crop protection, significantly more expensive than in the past, guar will decrease further in the long run and to less irrigation than other crops and remain a very competitive , sustainable stabil ise on a sustainable level, where acts as a nitrogen binder for the seil, functional ingredient if compared with farmers will see guar as an interesting which significantly reduces the need for potential substitutes.
124 PERSONAL CARE April 2013 The complexation of the metaborate- ion (B(OH)4-) by monosaccharides results in a @ cross- linking between the polysaccharides that constitute guar. This cross-linking retards or inhibits the swelling of guar Fruit Extracts at alkaline conditions. By lowering pH the cross-linking is e broken as the metaborate ion is converted to boric acid and rapid swelling may be ~ induced. Thi s effect proved very useful in processing guar derivatives, as it allows for u trouble-free dispersion of guar derivatives .~ without formation of lumps at alkaline pH and rapidly induced swelling in a second step. The concentration of boric acid and § borates in guar derivatives is usually low, /' e.g. 1%. ~ Considering the usual application concentration of guar derivatives in cosmetic formulations, e.g. typical levels o of guar hydroxypropyl trimonium chloride in conditioners are around 0.2% to 0.4%, then the concentrations of boric acid and ~ borates induced from guar derivates as ca rry-over into the final product were well From our product range: below 100 ppm. Consequently, one would have to absorb the boric acid and borates of about 0.5 kg of final product per kg of bodyweight in order to reach reported NOAEL (No Observed Adverse Effect Level) values. Given that dermal absorption through Acerola Elder Kaki intact skin is very low, it is obvious, that Malpighia glabra Sambucus nigra Diospyros kaki these levels have not prompted widespread • \! (,~ I~ - concern . Nevertheless, increased scrutiny ~. with regards to boric acid and borates and .... ~ . ~ perce ived reputational risks associated with If» . i - . ,. ~ their use, howeve r, have led to ambitious .#'/ ,I I efforts to eliminate it from guar deri vatives. - . ~ -, All major suppliers of guar derivatives for Carambola Cranberry l emon the cosmetic industry now offer 'boron free' Averrhoa carambola Vaccinium Citrus limon varia nts of thei r products, which offer the macrocarpon same functionality.
Conclusion Ask for a complete list of our product range. Given the historic pre-eminence of borated Plant extracts, naturally from guar derivatives and their widespread use Botanica®! in the cosmetics industry, the arrival of the 'boron free' variants was welcomed . The Botamca® GmbH shift from traditional borated guar derivates Industrie Nord • CH-5643 Sins to their variants, howeve r, has been rather Tel +41 (0)41 7570000 . Fax +41 (0)41 7570001 slow so far and the pre-eminence of [email protected] borated guar derivatives persists. This resilience may be explained by the low concentration of boric acid and bora tes in the final prod uct and consequently the low levels of risks attributed to its presence in conjunction with the advantages in processing borated guar derivatives. Rather than reformulating existing products, the industry is therefore using boron free variants of guar derivatives in new developments and the shift from borated to boron free products may be considered a long term trend in the cosmetics indust!)'. Iz:J
April 2013 PERSONAL CARE 125