stable liquid freezing at below -30 ° C and an initial boiling point of 130 ° C . It is free of hazard classification , and readily biodegradable . The product has very high naturality , with I n and I no
= 1 , according to ISO 16128 .
2,3-BD spreads very readily , with lower coefficient of friction than commonly used ingredients with a similar function , such as 1,3-BD , 1,3-propanediol ( 1,3-PD ) and glycerine . In sensorial profiling , is reported to have a light , lubricious feel , and to give high hydration with no greasy after-feel . In all aspects , the sensorial performance of 2,3-BD was rated superior to that of synthetic 1,3 BD .
Humectancy & moisture retention
Humectants are compounds that can absorb moisture , either from their substrate , or from the atmosphere . In cosmetic formulations , they are used to hydrate the surface layers of skin . The humectancy of 2,3-BD was compared to that of 1,3-BD and 1,3- PD , by applying a serum containing 3 % of the test humectant at 2 µ l / cm 2 to the forearm .
The moisture content of the skin was measured at zero , one , two and four hours , together with the rate of trans-epidermal water loss ( TEWL ). The results of the test substances are reported relative to the values before the application of the test serum .
As Figure 1 shows , 2,3-BD shows a superior effect in both humectancy and TEWL reduction compared to the synthetic analogues . The skin hydration shows a greater increase , and for a longer time , while the rate of moisture loss is also reduced to a greater degree over a longer period . The humectant properties of 2,3-BD have been exploited commercially in skin products and as anti-frizz agents in haircare .
Dispersant properties
2,3-BD can also be shown to perform as an effective dispersion agent , allowing stable and homogeneous dispersions of ingredients that can be difficult to incorporate into aqueous emulsions or formulation . A typical example would be the incorporation of a ceramide into an aqueous formulation . Typically , this involves pre-dispersing or dissolving the ceramide in an emollient or solvent at elevated temperatures of up to 130 ° C in extreme cases .
Dispersions of 1 % Ceramide III were prepared using 2,3-BD , 1,3-BD and 1,3- PD . The samples were heated to 90 ° C and cooled to 30 ° C before storing at room temperature for eight weeks . After this time , the dispersion using 1,3-PD had separated , with the ceramide aggregating on the top of the sample . The dispersions in 2,3-BD and 1,3-BD were stable , but the 1,3-BD sample had increased in viscosity to > 9,000 mPas at 25 ° C , while that of the 2,3 BD dispersion was ~ 3,700 mPas at 25 ° C .
Further testing showed that this dispersion could be successfully incorporated into a variety of cosmetic formulations with no adverse effect on the formulation properties . Additionally , a sample of the 2,3-BD dispersion stored at 45 ° C completely dissolved the ceramide . Similar testing on vitamin C and allantoin showed superior performance by 2,3-BD in the preparation of homogeneous and stable dispersions .
An expert panel assessed the dispersion of 15 % vitamin C in a polyol / oil emulsion for spreadability , smoothness and stability . Whilst all of the samples were found to be equally stable on storage , the 2,3-BD formulation was judged to be the most easily spreadable and smoothest .
2,3-BD therefore gives the cosmetic formulator a useful and effective ingredient to help incorporate difficult ingredients into formulations , while maintaining high formulation naturality .
Further cosmetic benefits
We have seen that 2,3-BD is an effective natural moisturising agent , humectant and dispersant , well suited to use in cosmetic formulations . Additional work has shown secondary benefits , which further contribute to advantages in use .
In the initial investigations into 2,3-BD in plants , a link between the substance and resistance to disease was found . 3 Laboratory investigations
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