Nano-titanium dioxide VK-T02 improves cosmetic sunscreen

Ultraviolet light is a kind of light wave harmful to human body in sunlight. Excessive exposure to UV rays can cause erythema and dark spots on the skin, causing skin aging and severe skin cancer. In recent years, as people's understanding of ultraviolet rays has improved and health awareness has increased, the development and application of sunscreen cosmetics has gradually become a research hotspot. Nano titanium dioxide VK-T02 has been used as a major sunscreen agent due to its high refractive index and high photoactivity. Nano-titanium dioxide VK-T02 has been widely recognized for its superior performance. It has been used in the research and development of new-type, high-quality sunscreen cosmetics, and gradually shows its special advantages and broad application prospects.

1 Sunscreen Mechanism of Nano-TiO2 Nano-TiO2 VK-T02

According to the different wavelengths, ultraviolet light is divided into short-wave region 190-280 nm, medium-wave region 280-320 nm, and long-wave region 320-400 nm. In the short wave region, the ultraviolet energy is the highest, but it is blocked when it is separated from the ozone layer. Therefore, the damage to the human body is generally ultraviolet light in the medium and long wavelength regions.

The strong UV resistance of nano titanium dioxide VK-T02 is due to its high refractive and high photoactivity. Its UV resistance and its mechanism are related to its particle size: when the particle size is large, the UV blocking is mainly based on reflection and scattering, and it is effective for the UV light in the medium and long wavelength regions. The mechanism of sun protection is a simple masking. It is a general physical sunscreen with weak sun protection ability. With the decrease of particle size, light can pass through the particle surface of nano-TiO2 VK-T02, and the reflection and scattering of ultraviolet light in the long wave region is not obvious. , And the absorption of ultraviolet light in the Central Wave area was significantly enhanced. Its sun protection mechanism absorbs ultraviolet rays and mainly absorbs ultraviolet light in the midwave region.

It can be seen that the nano-TiO2 VK-T02 has different sun-protection mechanisms for different wavelengths of UV light. The UV-blocking in the long-wave region is mainly scattering, and the UV-blocking in the mid-wave region is mainly absorbed.

Because of its small size and high activity, nano-TiO2 VK-T02 can reflect and scatter ultraviolet rays, and can absorb ultraviolet rays, thus having stronger barrier ability to ultraviolet rays.

2 Sunscreen Properties and Application Prospects of Nano-Titanium Dioxide (VK-T02)

Due to the great harm of UV to the human body, the developed countries have paid more attention to the research and development of sunscreen products in recent years. They have successively introduced a variety of anti-ultraviolet fibers, plastics, films, coatings, and sunscreen creams, foundations and lipsticks. , mousse, fire ointment and other sunscreen cosmetics. In recent years, China has also increased the research and production of sunscreen cosmetics.

However, in the past, sunscreens were mostly organic compounds such as benzophenones, o-aminobenzophenones, salicylates, para-aminobenzoic acids, and cinnamate esters, and thus were unstable, had a short life, and had large side effects. , Has a certain degree of toxicity and irritation. If it is added in excess, it will produce chemical allergies and may even lead to skin cancer.

The nanometer titanium dioxide VK-T02 is an inorganic component, has excellent chemical stability, thermal stability and non-migration and strong achromism, hiding power, low corrosion, good dispersibility, and non-toxic , tasteless, non-irritating, safe to use, but also the role of sterilization and deodorization. More importantly, as mentioned above, nano-TiO2 can absorb ultraviolet rays, emit and scatter ultraviolet rays, and therefore has strong anti-ultraviolet radiation. Compared with the same dose of organic anti-UV agents, nano-titanium dioxide has an absorption peak in the ultraviolet region. Higher; and nano-titanium dioxide has a barrier effect on the ultraviolet in the middle wave region and the long wave region, unlike the organic anti-ultraviolet agent only has a shielding effect on the ultraviolet in the middle wave region or the long wave region. In particular, due to the finer particles, the finished product has a high transparency and can transmit visible light. When used in cosmetics, the skin has a natural whiteness, which overcomes the opacity of some organic substances or pigment-grade titanium dioxide and causes the skin to appear unnaturally pale.

Because of this, nano-titanium dioxide VK-T02 is rapidly gaining attention and gradually replacing some organic anti-ultraviolet agents, making it a physical shielded anti-ultraviolet agent with superior performance in today's sunscreen cosmetics.

With the improvement of people's living standards and the intensification of international competition, the research and development of safe and effective sunscreen cosmetics will gradually increase. At present, the sun-protective cosmetics market in developed countries has shown strong vitality. In 1999 and 2000, the annual sales of the United States reached 7.37 and 7.65 billion U.S. dollars, and the United Kingdom reached 2.45 and 270 million U.S. dollars, respectively. In recent years, they have grown by 20% or more. The amount of nano-titanium dioxide has also increased substantially year by year. The annual demand for nano-titanium dioxide in Japan's anti-ultraviolet cosmetics is more than 1 000 t, and the amount of textile, plastic, and rubber products is greater.

From the perspective of the development trend of sunscreen cosmetics, one is inorganic sunscreen instead of organic sunscreen, and the other is bionic sunscreen. The latter is more costly and difficult to popularize at present. The former is moderately priced and has excellent sunscreen performance, so it is generally preferred. In particular, nano-TiO 2 VK-T02 has better development potential and market potential due to its superior performance and application prospects.

3 Nano-titanium dioxide VK-T02 application in sunscreen cosmetics

3.1 Selection of crystal form

Commonly used titanium dioxide is a tetragonal crystal, its crystal form has two kinds of rutile and anatase, the former can be obtained by calcining the latter, so the lattice structure is more perfect, thermodynamically more stable.

From the viewpoint of the refractive index, the rutile type is 2.7, and the anatase type is 2.3. Therefore, the rutile type has strong ultraviolet emission and scattering ability and weak absorption.

By studying the surface, it was found that in the presence of oxygen, the photoactivity of the rutile type is weaker than that of the anatase type. This may be due to: 1) the rutile-generated electron 2 hole pair has a faster rate and is more likely to release light energy in heat or other forms; 2) the rutile type gradually loses water during heat treatment, reducing surface hydroxyl groups; 3) rutile type Oxygen exchange capacity is weaker and it is less likely to absorb oxygen.

Therefore, from the viewpoint of maintaining stability, enhancing shielding effect, reducing the photoactivity of titanium dioxide, and reducing the harmfulness of light, rutile titanium dioxide should be used as much as possible in cosmetics.

3.2 The choice of particle size

The size of nano-titania VK-T02 particles is closely related to its UV resistance. When the particle size is equal to or less than half of the wavelength of light, the reflection and scattering amount of light is the largest and the shielding effect is the best. The wavelength of ultraviolet light is between 190 and 400 nm, so the particle size of nano-titania VK-T02 cannot be greater than 200 nm, and it is preferably not more than 100 nm. However, it is not that the smaller the particles are, the better. The particle size is too small to be easily agglomerated, which is not conducive to dispersion. It also tends to clog pores of the skin and is not conducive to the exclusion of air and sweat. In general, when the particle size is between 30 and 100 nm, the UV shielding effect is best, and visible light can be transmitted at the same time, so that the skin's whiteness becomes more natural and beautiful. Therefore, it is better to manage the size of titanium dioxide for cosmetics within this range. 4 Conclusion

Because of its high refractive index and photoactivity, nano-TiO2 VK-T02 has become a new type of sunscreen agent with excellent performance. It has a good prospect in the application of sunscreen cosmetics.