When it comes to chemical products, it often gives people a feeling of gray color, irritation and pollution. Of course, the functionality of chemical products is the first element; but after meeting the functional requirements, we can also add brilliant colors to chemical products to make them look pleasing to the eye. Today, I will introduce a variety of colorants used in polyurethane products.
According to the chemical composition, the colorants used in polyurethane include inorganic colorants and organic colorants. And each can be divided into two kinds of pigments and dyes. Generally speaking, the coloring methods of pigments and dyes are different. Dyes can penetrate into the interior of objects for coloring, such as the interior of fibers; while pigments can only act on the surface of objects. Both pigments and dyes come in a variety of colors.
According to polyurethane products, different polyurethane products use different amounts of colorants and colors. Among them, a large amount of colorants are used in synthetic leather, which is the largest category of colorants in polyurethane products. In 2019, the consumption of colorants for synthetic leather was close to 200,000 tons, more than half of the consumption of the entire polyurethane industry.
Followed by the polyurethane sole industry. China is a big shoe-producing country in the world, with thousands of sole manufacturers. Compared with soles made of other materials, polyurethane soles have many advantages such as lightness, wear resistance, soft texture, and non-slip. Black, white, gray, brown colorants are commonly used for shoe soles. In 2019, the consumption of colorants is 8,000 tons.
Polyurethane soft foam is used in household, cushion and other fields. Soft foam coloring, in addition to giving the product a color, can also distinguish the density, flame retardancy, quality grade, etc. of the soft foam. It is very convenient to use and also conducive to product standardization. In 2019, 12,000 tons of colorants will be consumed for soft foam products.
There are three types of polyurethane elastomers: thermoplastic (TPU), mixing type (MPU) and casting type (CPU) . Among them, colorants are widely used in TPU, but rarely used in MPU and CPU. Common TPU wheels, spacers, wire and cable sheaths are available in various colors. In 2019, polyurethane elastomers consumed 300 tons of colorants.
The output of rigid polyurethane foam is very large, but rigid foam is mainly used in the field of heat preservation and used in the inner cavity of products, so the proportion of coloring agent used in rigid foam is very low.
According to different functions, polyurethane coatings include primers, topcoats, and varnishes. Base coats and top coats don’t need color, while top coats need rich, colorful colors. Correspondingly, the colorants used in topcoats are also very rich, including various systems such as inorganic colorants and organic colorants. In 2019, polyurethane coatings consumed 4,500 tons of colorants.
With the basic colorant, any other color can be obtained by mixing the basic colorant. Among the rich and colorful colorants, people continue to research and develop new products. The new colorant will be more efficient, cheaper, healthier and more environmentally friendly.
