The company believes the effects of pollutants on hair is becoming an issue for Japanese consumers.
According to a recent survey conducted by the firm’s Hair Care Research Laboratory, more than half of the respondents expressed concerned for hair and scalp cleanliness, which was defined as the “smooth and dry feeling” of hair.
More than 60% identified that they were most concerned about the effects of dirt and dust particles and suspected them to be the cause of hair texture degradation and an ‘unclean’ feeling the day after shampooing.
Researchers undertook a month-long study to observe how particulate matter such as fine dust and pollen attaches itself to hair and clothes.
During the period from March to April 2019, a hairpiece, hair bundle, and clothes were placed outside for a few hours each day and measured for pollutants.
For the study, Cedar pollen was used as a representation of fine dirt particles.
After a month, the study showed that based on unit area, hair caught more or equal amount of pollutants than fabrics such as wool, cotton and polyester.
Oil control the key?
Based on the study of particle adhesion to hair and clothes, it was hypothesised that the presence of oil on the hair and scalp could be causing the particulate matter to adhere onto hair.
As such, the team explored existing technologies controlling oil on hair.
To reduce sebum in its liquid state, the team screened various oil-absorbent substances, including cationized hydorxypropylcellulose (C-HPC), a polymer which was developed in the Kao laboratory.
When added to a shampoo, C-HPC was found to lessen static friction, which in turn reduced fine dirt particles adhesion on the hair even after 20 hours after shampooing.
Six subjects with black hair were recruited to test the shampoo with C-HPC and a conditioner with low-viscosity silicone for six days on one side of the head.
After six days, the researcher collected the black hair samples and exposed them to fine white particles
Research staff members then observed and evaluated the colour change caused by the white particles.
They concluded that that adhesion of fine dirt particles was significantly inhibited by the use of the test products.
Kao said the findings obtained in this study would be used for the future development of hair care technology and formulations.
The findings of this study were presented at the Annual Autumn Meeting of the Society of Fibre Science and Technology in November 2019.