How to choose a colorant for plastic coloring?

1 PVC coloring agent

PVC is an important class of general-purpose thermoplastic materials for a wide range of applications, including common low-end and high-end special performance requirements such as building materials, automobiles, doors and windows. Due to its low processing temperature, it can be colored by various types of organic pigments. However, the colorant should be selected according to the processing conditions and the end use of the colored product. Of course, the phenomenon of blooming when PVC is colored should be avoided. .

The blooming phenomenon when PVC is colored can be considered to be caused by the partial dissolution of the organic pigment as a coloring agent at the processing temperature and the recrystallization of the pigment at room temperature. This phenomenon also exists in other polyolefin plastics, especially Soft PVC material, because the added plasticizer increases the solubility of the colorant in it, making it more prone to blooming, and as the processing temperature increases, the blooming phenomenon becomes more serious; further, due to the pigment and PVC The compatibility between them is not ideal, especially when some additives are added, which will lead to the supersaturation of the pigment and the appearance of surface precipitation. Therefore, for the coloring of PVC, different grades of organic pigments can be selected according to different requirements:

1 universal colorant, good economical, but generally durable (yellow, orange and red) varieties: CI Pigment Yellow 61, CI Pigment Yellow 168, CI Pigment Orange 13, CI Pigment Orange 34, CI Pigment Red 48: 1. CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 57:1, CI Pigment Red 57:2.

2 excellent coloring agents (yellow, orange and red): varieties are CI Pigment Yellow 139, CI Pigment Yellow 183, CI Pigment Yellow 191, CI Pigment Orange 43, Graphtol Fast Orange 5GL, CI Pigment Red 151, CI Pigment Red 214 , CI Pigment Red 242.

3 Colorants suitable for outdoor coloring products are: CI Pigment Yellow 24, CI Pigment Yellow 110, CI Pigment Brown 23, CI Pigment Brown 25, CI Pigment Red 122, CI Pigment Blue 15, CI Pigment Blue 60, CI Pigment Green 7, CI Pigment Violet 23.

2 PA coloring agent

The colorant used for the PA may be either an organic pigment or a dye dissolved in a polymer. Organic pigments for PA coloring can be divided into two grades:

1 Application performance General organic pigment varieties are: CI Pigment Yellow 148, CI Pigment Yellow 150, CI Pigment Yellow 187, CI Pigment Red 149, CI Pigment Red 177, CI Pigment Violet 23.

2 The organic pigments with excellent performance are: CI Pigment Yellow 192, CI Pigment Orange 68, CI Pigment Blue 15:3, CI Pigment Green 7. Among them, CI Pigment Yellow 192 is a bright red-yellow yellow heterocyclic pigment without metal. It has high heat stability (300 ° C) and excellent weather fastness at low concentration, and can be combined with titanium dioxide and zinc sulfide. Inorganic pigments are used in combination; CI Pigment Orange 68 is a bright red orange nickel complex pigment containing a benzimidazolone group, which has excellent light and heat resistance.

3 Colorants for polyester materials

Polyester materials (including PET and PBT) can be pigmented with pigments such as CI Pigment Yellow 138, CI Pigment Yellow 147, CI Pigment Red 214, CI Pigment Red 242, etc., but more often with solvents that are soluble in the polymer. Dye coloring, such as Estofil S (Clar), Polysynthren (Hö), Filester (Ciba), and the like.

4 ABS colorants

The coloring of ABS mostly uses solvent dyes which are soluble in polymers, which not only have good transparency, but also good light fastness. If used together with inorganic pigments, opaque colored products can be obtained, and commonly used polymers are soluble. The solvent dyes include CI Solvent Yellow 93, CI Solvent Orange 60, CI Solvent Red 111, CI Solvent Red 135, CI Solvent Blue 104, CI Solvent Green 3, and the like.

5 PS, SAN (styrene-acrylonitrile copolymer), PMMA, PC and CAB colorants

These thermoplastics have excellent transparency. In order to maintain the original transparency of the colored products, in addition to the coloring of some of the above pigments, solvent dyes and disperse dyes with high solubility are preferably used to dissolve them in the coloring process. A stable molecular solution is formed in the plastic, showing high color strength, such as Macrolex series dyes (By), varieties are Macrolex Yellow 6G, Yellow G, Yellow R, Orange GG, Red GS, Red 5B, Red 7B, Violet R, Violet 3R Violet B, Green 5B, they are used in an amount of 0.025% to 0.05%, and heat resistance can reach 280 to 300 °C.