In the process of blow molding, we will add colorant to the plastic to make the plastic coloring, plastic coloring is also an important processing process of blow molding. Reasonable selection of colorants, fully understand the properties and characteristics of colorants, in order to carry out the corresponding formula design, to ensure that the color of blown products to meet the needs of consumers.
There are many colors of blow molded bottle products, but few single colorants are used for coloring, and several colorants are often used for color matching. Two or more colorants of different colors, mixed after coloring, can get another color called patchwork color. Color combination refers to the three primary colors of red, yellow and blue, mixed into different colors according to different proportions.
The following aspects should be considered in the selection of colorants.
(1) Color light. The color light of the colorant refers to the color and brightness of the colorant on the dyed object. A basic color that has different shades of light, such as red, blu-red, yellow-red, etc. The color light is divided into bright and gray, and the color light is an important sign of the characteristics and quality of the colorant. For the application of colorant, mastering the colorant color light is an important guarantee for the quality of colorant processing products.
(2) Coloring power. Coloring power is the main index to identify the quality of colorant. The amount of colorant is related to the coloring power of colorant. Colorant with strong coloring power and small dosage; The colorant with weak coloring power is used more. Colorant of the same quality, deep color with large coloring force; The color power is small, the color is light.
(3) Fastness to sunlight. The colorant on plastic products absorbs and reflects light. After absorbing light energy, the colorant produces photochemical reaction, resulting in fading and discoloration, and its degree determines the quality of the fastness to sunlight. When choosing a colorant, you must choose a colorant with good fastness to sunlight, especially for products used outdoors.
(4) Hygiene. Generally, hollow products in contact with food should not be colored as far as possible. If coloring is needed, non-toxic or low-toxic colorants that meet food hygiene standards should be selected.
(5) Good heat resistance. The heat resistance of the colorant must be suitable for the molding temperature and use temperature of the plastic production process. At its molding processing temperature, it can keep the color bright and colorless.
(6) Good dispersion. Plastic in the molding process, the colorant should be evenly dispersed, such as uneven dispersion, on the surface of the product will produce stains.
(7) Good migration resistance. The color of the product is not easy to be extracted or transferred.
Colorants are divided into pigments and dyes. Dyes soluble in water, oil, solvents and other media!
Bright color, strong coloring power, transparent, but the heat resistance, migration resistance is poor, so most of them are not hungry for plastic coloring. Pigments are insoluble in media such as water, oil, etc. Plastic coloring can use colorants are basically pigments, pigments are divided into inorganic pigments and organic pigments.
