Safety considerations for pigment selection
Lipstick comes into direct contact with the lips, so the safety of the pigment is the primary factor. In the selection process, both regulatory authorities and the cosmetics industry follow strict standards. Internationally, there are standards such as the EU Cosmetics Regulations and the US FDA standards, which clearly specify the list of pigments that can be used in Lipstick and the limits of use. For example, some natural pigments such as β-carotene, extracted from natural ingredients such as carrots, are relatively safe and nutritious ingredients for the human body and are often given priority. For synthetic pigments, such as CI15850 (Red 7), a large number of toxicological tests must be conducted, including evaluations of their carcinogenicity, teratogenicity and sensitization. Only pigments that do not cause any harm to the human body at normal dosages will be selected into the Lipstick formula. Moreover, different countries may have different safety requirements for pigments, and producers need to meet both local and international regulations to ensure that consumers will not be threatened with health when using Lipstick. This is an extremely complex and rigorous screening process involving numerous experiments and evaluation links.
Pigment selection based on color effects
Lipstick's rich and diverse colors meet the aesthetic needs of different consumers, so the color characteristics of the pigment are one of the keys to selection. From the perspective of color, red is the classic color of Lipstick, and its pigment comes from a variety of sources. Carminic acid from cochineal extract can provide a rich and bright red, which is a good choice for creating popular lip colors such as retro red. For some special tones, such as the purple-red in cool-toned Lipstick, it is necessary to mix and match synthetic blue pigments with red pigments. At the same time, the stability of the pigment is crucial, which determines the color retention ability of Lipstick during storage and use. Whether in hot summer or under different lighting conditions, high-quality pigments should ensure that the color of Lipstick remains unchanged. For example, the chemical structure of some metal complex dyes makes them have excellent stability in complex environments. In addition, the transparency and hiding power of the pigment also affect the final effect of Lipstick. For lipsticks that require high hiding power, pigment-based pigments such as titanium dioxide are often used, which can make the lipstick color present a uniform effect on lips of different lip colors; while for lip gloss products that pursue a moist and transparent feeling, highly transparent pigments will be selected to create a light makeup effect.
Pretreatment of pigments
Before processing lipsticks, pigments need to be pretreated. For natural pigments, extraction and purification are important steps. Taking safflower yellow pigment as an example, when it is extracted from safflower, professional extraction technology is required, and then impurities are removed by filtering, centrifugation and other methods to ensure that the pigment reaches a high purity. This series of processes requires precise control of conditions to maximize the retention of the effective ingredients and color characteristics of the pigment. For synthetic pigments, due to the particularity of their production process, operations such as crushing and screening may be required. Making synthetic pigments into a suitable particle size is to ensure their dispersibility in lipsticks. If the particle size is uneven or too large, the pigment is easy to agglomerate during the subsequent mixing process, resulting in uneven color of lipsticks. The appropriate particle size can make the pigment better integrated into the Lipstick system when mixed with other ingredients, thereby ensuring the stability of Lipstick quality and the uniformity of color, which is an important preliminary work to ensure the quality of Lipstick.
Mixing, dispersion and quality inspection of pigments
In the production of Lipstick, pigments must be fully mixed with other ingredients such as wax, oil, and emollients. Usually, the matrix such as wax and oil is heated and melted to form a uniform liquid environment, and then the pigment is added. In this process, high-speed stirring is the key, and the stirring speed may be as high as several hundred revolutions per minute, and the continuous stirring time ranges from tens of minutes to several hours. Through this strong stirring, the pigment is evenly dispersed in the matrix. Sometimes, in order to further optimize the dispersion effect of the pigment, dispersants are added. These dispersants are mostly surfactants, which can reduce the surface tension between the pigment particles and the matrix, so that the pigment can be more evenly distributed in the Lipstick system. After the processing is completed, it is an essential step to detect the quality of the pigment in Lipstick. On the one hand, scientific methods such as colorimetry and spectrophotometry are used to detect whether the color meets the predetermined standards, including specific indicators such as color depth and hue. For example, a spectrophotometer is used to measure the absorbance of Lipstick at a specific wavelength and compare it with a standard color card or a pre-set value to ensure the accuracy of the color. On the other hand, the stability of the pigment is tested by simulating different environmental conditions such as high temperature, high humidity and light, and observing the color changes of Lipstick to ensure that Lipstick will not have quality problems such as fading and discoloration during storage and use, thereby providing consumers with high-quality Lipstick products.
