The facial mask market has become the fastest growing cosmetic segment in recent years. According to Mintel’s survey report, in 2016, facial mask products ranked second in the frequency of use by Chinese consumers among all skin care product categories, of which face mask is the most popular product form. In the face mask products, the mask base cloth and the essence are an inseparable whole. In order to achieve the ideal use effect, special attention should be paid to the compatibility and compatibility test of the mask base cloth and the essence during the product development process. .

foreword
Common mask base fabrics include tencel, modified tencel, filament, natural cotton, bamboo charcoal, bamboo fiber, chitosan, composite fiber, etc.; the selection of each component of the mask essence includes rheological thickener, moisturizing agent , functional ingredients, choice of preservatives, etc. Hydroxyethyl cellulose (hereinafter referred to as HEC) is a non-ionic water-soluble polymer. It is widely used in the cosmetic industry due to its excellent electrolyte resistance, biocompatibility and water-binding properties: for example, HEC is a facial mask essence. The commonly used rheological thickeners and skeleton components in the product, and it has a good skin feel such as lubricating, soft and compliant. In recent years, the activity of new facial masks has increased significantly (according to Mintel’s database, the number of new facial masks containing HEC in China increased from 38 in 2014 to 136 in 2015 and 176 in 2016).

experiment
Although HEC has been widely used in facial masks, there are few related research reports. The author’s main research: different types of mask base cloth, together with the formula of HEC/xanthan gum and carbomer selected after the investigation of commercially available mask ingredients (see Table 1 for the specific formula). Fill in 25g liquid mask/sheet or 15g liquid mask/half sheet, and press lightly after sealing to fully infiltrate. Tests are performed after a week or 20 days of infiltration. The tests include: the wettability, softness and ductility test of HEC on the mask base fabric, the human sensory evaluation includes the softness test of the mask and the sensory test of the double-blind half-face random control, in order to develop the formula of the mask and systematically. Instrument test and human sensory evaluation provide reference.

Mask Serum Product Formulation

The amount of carbs is fine-tuned according to the thickness and material of the mask base cloth, but the amount added for the same group is the same.

Results – Mask wettability
The wettability of the mask refers to the ability of the mask liquid to infiltrate the mask base cloth evenly, completely, and without dead ends. The results of infiltration experiments on 11 kinds of mask base fabrics showed that, for thin and medium thickness mask base fabrics, the two types of mask liquids containing HEC and xanthan gum could have a good infiltration effect on them. For some thick mask base fabrics such as 65g double-layer cloth and 80g filament, after 20 days of infiltration, the mask liquid containing xanthan gum still cannot fully wet the mask base fabric or the infiltration is uneven (see Figure 1); The performance of HEC is significantly better than that of xanthan gum, which can make the thick mask base cloth more fully and completely infiltrate.

The wettability of face masks: a comparative study of HEC and xanthan gum

Results – Mask Spreadability
The ductility of the mask base fabric refers to the ability of the mask base fabric to be stretched during the skin-sticking process. The hanging test results of 11 kinds of mask base fabrics show that for medium and thick mask base fabrics and cross-laid mesh weave and thin mask base fabrics (9/11 kinds of mask base fabrics, including 80g filament, 65g Double-layer cloth, 60g filament, 60g Tencel, 50g bamboo charcoal, 40g chitosan, 30g natural cotton, 35g three kinds of composite fibers, 35g Baby silk), the microscope photo is shown in Figure 2a, HEC has moderate ductility, can be Adapt to different sized faces. For the unidirectional meshing method or the uneven weaving of thin mask base fabrics (2/11 kinds of mask base fabrics, including 30g Tencel, 38g filament), the microscope photo is shown in Figure 2b, HEC will make it excessively stretched and occur visibly deformed. It is worth noting that the composite fibers blended on the basis of Tencel or filament fibers can improve the structural strength of the mask base fabric, such as 35g 3 kinds of composite fibers and 35g Baby silk mask fabrics are composite fibers, even if they are It belongs to the thin mask base fabric and also has good structural strength, and the mask liquid containing HEC will not make it excessively stretched.

Microscope photo of mask base cloth

Results – Mask Softness
The softness of the mask can be evaluated by a newly developed method to quantitatively test the softness of the mask, using a texture analyzer and a P1S probe. Texture analyzer is widely used in the cosmetic industry and food industry, it can quantitatively test the sensory characteristics of products. By setting the compression test mode, the maximum force measured after the P1S probe is pressed against the folded mask base cloth and moved forward for a certain distance is used to characterize the softness of the mask: the smaller the maximum force, the softer the mask.

The method of texture analyzer (P1S probe) to test the softness of the mask

This method can well simulate the process of pressing the mask with fingers, because the front end of human fingers is hemispherical, and the front end of the P1S probe is also hemispherical. The hardness value of the mask measured by this method is in good agreement with the hardness value of the mask obtained by the sensory evaluation of the panelists. By examining the influence of the mask liquid containing HEC or xanthan gum on the softness of eight kinds of mask base fabrics, the results of instrumental testing and sensory evaluation show that HEC can soften the base fabric better than xanthan gum.

Quantitative test results of the softness and hardness of the mask base cloth of 8 different materials (TA & sensory test)

Results – Mask Half Face Test – Sensory Evaluation
6 kinds of mask base fabrics with different thicknesses and materials were randomly selected, and 10~11 trained sensory evaluation expert assessors were asked to conduct half-face test evaluation on the mask containing HEC and xanthan gum. The evaluation stage includes during use, immediately after use and evaluation after 5 minutes. The results of the sensory evaluation are shown in the table. The results showed that, compared with xanthan gum, the mask containing HEC had better skin adhesion and lubricity during use, better moisturizing, elasticity and gloss of the skin after use, and could prolong the drying time of the mask (for the investigation 6 kinds of mask base fabrics, except that HEC and xanthan gum performed the same on 35g Baby silk, on the other 5 kinds of mask base fabrics, HEC can prolong the drying time of the mask by 1~ 3min). Here, the drying time of the mask refers to the application time of the mask calculated from the time point when the mask starts to dry as felt by the assessor as the end point. Dehydration or cocking. The expert panel generally preferred the skin feel of HEC.

Table 2: Comparison of xanthan gum, skin feel characteristics of HEC and when each mask containing HEC and xanthan gum dries out during application

in conclusion
Through the instrument test and human sensory evaluation, the skin feel and compatibility of the mask liquid containing hydroxyethyl cellulose (HEC) in various mask base fabrics were investigated, and the application of HEC and xanthan gum to the mask was compared. performance difference. The results of the instrument test show that for mask base fabrics with sufficient structural strength, including medium and thick mask base fabrics and thin mask base fabrics with cross-laid mesh weaving and more uniform weaving, HEC will make them moderately ductile; Compared with xanthan gum, HEC’s facial mask liquid can give the mask base fabric better wettability and softness, so that it can bring better skin adhesion to the mask and be more flexible for different face shapes of consumers. On the other hand, it can better bind moisture and moisturize more, which can better fit the principle of use of the mask and can better play the role of the mask. The results of the half-face sensory evaluation show that compared with xanthan gum, HEC can bring better skin-sticking and lubricating feeling to the mask during use, and the skin has better moisture, elasticity and gloss after use, and can prolong The drying time of the mask (can be extended by 1~3min), the expert evaluation team generally prefers the skin feel of HEC.