【Mandom Co., Ltd.】
Mandom and Kyoto University develop hair styling technology that keeps the hair style natural finish by forming a strong bond to moisture inside the hair

Mandom Corporation Mandom and Kyoto University Develop Hair Stabilization Technology to Keep Hair Style Natural Finish by Forming a Strong Bond to Humidity in the Hair Joint release of Mandom and Kyoto University, a national university corporation ………………………………………………………………………………………… Mandom Co., Ltd. (Head office: Osaka City, President & Executive Officer: Motonobu Nishimura and below Mandom) and Kyoto University (National office: Kyoto City, President: Ryoichi Yamagiga following and Kyoto University) Kashiwazaki Katsuhiro has been working jointly since 2014 on the development of hair styling technology that “keeps the hair finished with a natural finish” required for hair styling agents today. Conventional hair styling technology maintains and maintains the hair style by applying and adhering hair styling ingredients to the outside of the hair, thereby firming or sticking the hair together. However, because a lot of hair styling components adhere to the outside of the hair, it tends to be less likely to have a natural gloss like hair, and the “natural finish” and “keep” required for recent hair styling agents It was difficult to make it compatible. Therefore, we considered that it would be possible to have a high keeping power even under high humidity if a strong bond was formed inside the hair, and we examined hair styling components that act inside. As a result, it was found that by permeating the hair with α-ketoglutaric acid, which has been used for moisturizers, it forms bonds within the hair and achieves a high keeping power while having a natural finish. This technology has made it possible to develop hair styling agents that can achieve the desired hairstyle with a natural finish, which could not be realized until now. The results of this research are scheduled to be presented at the 30th International Cosmetic Technologists Conference (IFSCC Conference), which will be held from 30th September to 2nd October 2019 in Milan, Italy. 1. Both natural finish and keeping of hairstyle Conventional hair styling technology keeps and keeps the hair style by applying and acting on hair styling ingredients such as set polymer and wax on the outside of the hair to harden or stick the hair together (Figure 1).
[Image 1: https://prtimes.jp/i/6496/480/resize/d6496-480-542689-0.jpg]
Therefore, if you increase the amount of hair-setting ingredients that act from the outside, the power to fix the hair becomes stronger, so the keeping power is improved and the gloss also tends to increase. This finish has been favored by many consumers in the past, but on the other hand, in recent years the number of consumers who prefer “natural finish” hairstyles has increased, especially for young men, and It is required to be able to “keep” the hairstyle of a “natural finish” (Figure 2). However, it is difficult to achieve a natural finish with conventional hair setting technology, so new technology was needed to realize this coexistence.
[Image 2: https://prtimes.jp/i/6496/480/resize/d6496-480-606987-1.jpg]
2. Search for hair setting components that penetrate and act on the inside, not the conventional action from the outside Humidity is the main reason you can not keep your hair style. In general, hair is formed by the formation of hydrogen bonds mainly between proteins inside. However, this hydrogen bond is very weak in water, and when it absorbs moisture, the bond breaks and the shape changes. This is one of the causes of the collapse of the hairstyle due to humidity (Figure 3).
[Image 3: https://prtimes.jp/i/6496/480/resize/d6496-480-330841-2.jpg]
Therefore, we thought that moisture resistance could be improved by permeating the ingredients inside the hair, forming stronger ionic bonds than hydrogen bonds between hair proteins, and increasing the number of action sites (Fig. 4).
[Image 4: https://prtimes.jp/i/6496/480/resize/d6496-480-169372-3.jpg]
Since proteins in the hair have positive sites, we thought that it would be possible to connect the hair proteins with one another by the action of dibasic acids having negative sites at both ends (Fig. 5). ).
[Image 5: https://prtimes.jp/i/6496/480/resize/d6496-480-479191-4.jpg]
As a result of examining various dibasic acids, it was found that α-ketoglutaric acid, which is used as a moisturizing ingredient, penetrates the inside of the hair and forms bonds internally, thereby enhancing the moisture resistance. In addition, it was confirmed that the appearance when applied to the hair was the same finish as the bare hair. In other words, by infiltrating α-ketoglutaric acid, it is possible to achieve both “natural finish” and “keep”. Penetration: The hair soaked with the aqueous solution of α-ketoglutaric acid was cut, and the concentration distribution of α-ketoglutaric acid on the cross section was measured using FT-IR (Fourier Transform Infrared Spectroscopy). As a result, it was confirmed that α-ketoglutaric acid penetrated to the hair center (Fig. 6).
[Image 6: https://prtimes.jp/i/6496/480/resize/d6496-480-447130-11.jpg]

Binding to hair proteins: In order to confirm whether the infiltrated α-ketoglutarate forms a bond with the hair protein, using SAXS (Small-Angle X-ray Scattering) which enables structural analysis of the substance at a microscopic size at Kyoto University We did verification. In SAXS, the hair is irradiated with X-rays, and the intensity of the scattered light allows you to know the structure of the protein in the hair. When the scattering intensity is high, it can be seen that the shapes and structures of proteins in the hair are regularly arranged. Also, the size of the scattering angle tells you where it works on the hair. (Figure 7).
[Image 7: https://prtimes.jp/i/6496/480/resize/d6496-480-10465-6.jpg]
As a result of SAXS measurement, by treating α-ketoglutaric acid on the hair, a remarkable difference in strength appeared in the area derived from the matrix protein as compared to the purified water-treated hair (Fig. 8).
[Image 8: https://prtimes.jp/i/6496/480/resize/d6496-480-700430-7.jpg]
In normal hair, when stored under high humidity, the structure of matrix protein breaks down, in hair impregnated with α-ketoglutarate, the matrix protein forms a regularly arranged structure, and this structure also depends on humidity. Was confirmed to be held. In other words, we found that α-ketoglutaric acid binds to matrix proteins in the hair and plays a role in forming a strong regular structure that does not change its structure with humidity. (Figure 9)
[Image 9: https://prtimes.jp/i/6496/480/resize/d6496-480-467933-8.jpg]
Moisture resistance: The hair bundle treated with α-ketoglutaric acid is curled and left dry in a high humidity environment of room temperature 25 ° C and humidity 80%, and the curl of hair bundle after 2 hours is maintained I have measured. Normally, when the hair gets damp, internal hydrogen bonds break and curls grow. In this study, we have compared the purified water-treated hair and the other dibasic acid, glutaric acid-treated hair, to what extent this curling due to moisture can be suppressed. As a result, it was found that by treating α-ketoglutaric acid, the curl elongation suppression ratio was higher and the keeping power was improved, as compared with the case of treating with purified water alone or the case of treating with glutaric acid. Figure 10).
[Image 10: https://prtimes.jp/i/6496/480/resize/d6496-480-870841-10.jpg]
Natural finish: By applying the hair bundle α-ketoglutaric acid and evaluating the glossiness of the dried hair surface, it was evaluated whether a natural texture can be realized. As a comparison, we also created hair bundles coated with purified water, set polymers (in-house hair gel) that are conventional hair setting components, and hair bundles coated with wax (in-house hair wax). As a result, the hair bundle coated with set polymer and wax has a greater sense of gloss compared to the case treated with purified water, while the hair bundle treated with α-ketoglutaric acid is treated with purified water only It was confirmed that it had the same level of gloss, that is, it had a natural look (Figure 11).
[Image 11: https://prtimes.jp/i/6496/480/resize/d6496-480-340445-9.jpg]
From the above, we succeeded in developing a hair styling technology that works from inside the hair by using α-ketoglutaric acid and can keep the hairstyle firmly even under high humidity. In the future, Mandom will apply this technology to hair styling agents that combine “natural finish” and “keep”.

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