BDMA is a catalyst for polyester type polyurethane block soft foam, polyurethane hard foam, polyurethane sheet and adhesive coating in polyurethane industry, mainly used in hard foam, which can make polyurethane foam with good pre-fluidity and uniform bubble pore, and good adhesion between foam body and substrate.
Surface area of the pigment
In order to stabilize the pigment used in paint and color paste, wax emulsion paint the necessary amount of dispersant is determined by the surface area of the pigment. The greater the surface area of the pigment, the greater the amount of dispersant used for stabilization. The pigment industry has stipulated some technical terms for the concept of surface area.
Oil absorption: the amount of linseed oil needed to wet a certain amount of pigment, expressed in g/100g.
BET value: The amount of monolayer nitrogen absorbed on the surface of the pigment is measured by the low-temperature nitrogen adsorption method, expressed in m²/g. DBP value: the amount of dibutyl phthalate required to wet a certain amount of pigment, usually used for carbon black, expressed in g/100g. 2. Pigment characteristics
Basically, we distinguish between organic and inorganic pigments. In addition, it can also be distinguished by particle size and chemical properties. Even pigments with the same color index have different basic characteristics and acidity.
Surface treatment of pigments
Pigment manufacturers use a variety of methods to change the weather resistance and dispersibility of pigments, many of which are technical secrets of the manufacturer, and some are explained by the pigment manufacturer.
For titanium dioxide, in order to reduce the damage to the coating film by light, other inorganic oxides, such as aluminum oxide, lead dioxide, and silicon dioxide, are wrapped on its surface to improve weather resistance. At the same time, the dispersibility can be further improved by adding trimethylolpropane (TMP).
Another example is carbon black. Oxidation aims to improve dispersibility.
For organic pigments, various substances are used for surface treatment to improve dispersibility, and manufacturers usually do not disclose the details.
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