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UV protection of human hair

IP.com Disclosure Number: IPCOM000246888D
Publication Date: 2016-Jul-12
Document File: 4 page(s) / 108K

Publishing Venue

The IP.com Prior Art Database

Abstract

UV protection for human hair is an important claim for hair care products, but scientifically valid proof of the effectiveness of formulations has been lacking so far. In this study, the UV protection effect of a shampoo/conditioner combination (rinse-off), a shampoo/conditioner (rinse-off) /mousse (leave-on) combination and a hair gel on human hair was investigated using a solar simulator for irradiation and Differential Scanning Calorimetry (DSC) to analyse the damage done to the hair protein structure by the UV light. The formulations contained the UV absorber combination Ethylhexyl Methoxycinnamate and Diethylamino Hydroxybenzoyl Hexyl Benzoate, which is effective in both the UVA and UVB range. Concentrations of Ethylhexyl Methoxy¬cinnamate and Diethylamino Hydroxybenzoyl Hexyl Benzoate were 0.1% for the shampoo, 2.5% for the conditioner, 0.2% for the mousse and 3% for the gel formulation.

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UV protection of human hair by shampoo/conditioner, shampoo conditioner/mousse or hair gel treatments

Introduction

UV protection for human hair is an important claim for hair care products, but scientifically valid proof of the effectiveness of formulations has been lacking so far.

In this study, the UV protection effect of a shampoo/conditioner combination (rinse- off), a shampoo/conditioner (rinse-off) /mousse (leave-on) combination and a hair gel on human hair was investigated using a solar simulator for irradiation and Differential Scanning Calorimetry (DSC) to analyse the damage done to the hair protein structure by the UV light. The formulations contained the UV absorber combination Ethylhexyl Methoxycinnamate and Diethylamino Hydroxybenzoyl Hexyl Benzoate, which is effective in both the UVA and UVB range. Concentrations of Ethylhexyl Methoxy- cinnamate and Diethylamino Hydroxybenzoyl Hexyl Benzoate were 0.1% for the shampoo, 2.5% for the conditioner, 0.2% for the mousse and 3% for the gel formulation.

Experimental

Natural blond, hair tresses,1.5 cm wide, 11.5 cm long hair strands, 0.5-0.6g, were cleaned for 30 min. with a 12% aq. solution of Texapon® NSO, rinsed with water for 10 min and subsequently blow-dried at 60°C for 1h.

The tresses were then incubated two times for five minutes with 0.25g shampoo formulation per gram hair or, in case of conditioner and mousse formulations, incubated for three minutes with 0.125g product per gram hair (Formulations table 1). After that the hair tresses were rinsed with water and dried as described above.

For leave-on treatment 4g product (Table 2) was applied per tress and homogenously distributed. Excess product was removed to keep just about 0.45 g of product on the hair. Finally the tress was dried under ambient conditions.

Three tresses were prepared for each type of treatment. The tresses thus prepared were irradiated for 72h in a Xenotest Alpha T (Atlas) at 120% power, 42°C and 42% relative humidity. Irradiation was done in the wavelength region 300-400 nm with an intensity of 150 W/m2.

The irradiated hair tresses were then prepared for DSC measurements using a Q100 DSC (TA Instruments). The measurements were performed as described by Wortmann and Deutz (J. Appl. Polym. Sci. 48 (1993) 137) and Wortmann et al. (J. Cosmet. Sci. 53 (2002) 219). In deviation from the protocol described by Wortmann, a heating rate of 2K/min was used here. The material from 3 tresses was mixed for each treatment. Analysis of the DSC thermograms was performed using the Universal Analysis software (version 4.7A, TA Instruments).

As described by Wortmann, the denaturation temperatures (Tmax and Tonset) are indicators for the amount and/or chemical composition (crosslink density and viscosity) of the non-helical protein matrix in which the intermediate filaments of the


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hair are embedded. The denaturation enthalpy is a measure for the content of α- helical material in the keratins and its...