Introduction to types and properties of commonly used colorants for plastics

Time:2023-03-15 09:11:04 / Popularity: / Source:

1. Colorants for PVC

PVC is an important general-purpose thermoplastic material with a wide range of uses, including commonly used low-grade and high-grade fields with special performance requirements, such as building materials, automobiles, doors and windows, etc. Due to its low processing temperature, various types of organic pigments can be selected. For coloring, colorant should still be selected according to processing conditions and final use of colored product. Of course, phenomenon of blooming when PVC is colored should be avoided.
colorants for plastics 
Blooming phenomenon when PVC is colored can be considered to be caused by partial dissolution of organic pigments as colorants at processing temperature and recrystallization of pigments at room temperature. This phenomenon also exists in other polyolefin plastics, especially for soft PVC material. Because added plasticizer increases solubility of colorants in it, it makes it easier to produce blooming phenomenon, and with increase of processing temperature, blooming phenomenon becomes more serious; in addition, since compatibility between pigment and PVC is not ideal, especially when certain additives are contained, this will lead to supersaturation of pigments and phenomenon of surface precipitation. Therefore, for coloring of PVC, different grades of organic pigments can be selected according to different requirements:
①Universal colorant, with good economy, but average durability (yellow, orange and red)
Varieties are C.I. Pigment Yellow 61, C.I. Pigment Yellow 168, C.I. Pigment Orange 13, C.I. Pigment Orange 34, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 57:1, C.I. Pigment Red 57:2.
②Colorants with excellent performance (yellow, orange and red)
Varieties are C.I. Pigment Yellow 139, C.I. Pigment Yellow 183, C.I. Pigment Yellow 191, C.I. Pigment Orange 43, Graphtol Fast Orange 5GL, C.I. Pigment Red 151, C.I. Pigment Red 214, C.I. Pigment Red 242.
③ Colorants suitable for outdoor coloring products
Varieties are C.I. Pigment Yellow 24, C.I. Pigment Yellow 110, C.I. Pigment Brown 23, C.I. Pigment Brown 25, C.I. Pigment Red 122, C.I. Pigment Blue 15, C.I. Pigment Blue 60, C.I. Pigment Green 7, C.I. Pigment Violet 23.

2. Colorants for PA

Colorants for PA can be either organic pigments or polymer-soluble dyes. Organic pigments for PA coloring can be divided into two grades:
Organic pigment varieties with general application performance are: C.I. Pigment Yellow 148, C.I. Pigment Yellow 150, C.I. Pigment Yellow 187, C.I. Pigment Red 149, C.I. Pigment Red 177, C.I. Pigment Violet 23.
Organic pigment varieties with excellent performance are: C.I. Pigment Yellow 192, C.I. Pigment Orange 68, C.I. Pigment Blue 15:3, C.I. Pigment Green 7. Among them, C.I. Pigment Yellow 192 is a bright red light yellow heterocyclic pigment without metal. It still has high thermal stability (300℃) and excellent weather fastness at low concentration, can be mixed with inorganic pigments such as titanium dioxide and zinc sulfide; C.I. Pigment Orange 68 is a bright red-orange nickel complex pigment containing benzimidazolone groups, with excellent light resistance and heat resistance.

3. Colorants for polyester materials

Polyester materials (including PET and PBT) can be colored with pigments, such as C.I. Pigment Yellow 138, C.I. Pigment Yellow 147, C.I. Pigment Red 214, C.I. Dyestuffs such as Estofil S (Clar), Polysynthren (Hö), Filester (Ciba) etc.

4. Colorants for ABS

Coloring of ABS mostly uses solvent dyes soluble in polymers, which not only have good transparency, but also good light fastness. If combined with inorganic pigments, opaque colored products can be obtained. Commonly used polymers are soluble in polymers. Solvent dyes are C.I. Solvent Yellow 93, C.I. Solvent Orange 60, C.I. Solvent Red 111, C.I. Solvent Red 135, C.I. Solvent Blue 104, C.I. Solvent Green 3, etc.

5. Colorants for PS, SAN (styrene-acrylonitrile copolymer), PMMA, PC and CAB (cellulose ester), etc.

These thermoplastics have excellent transparency. In order to maintain original transparency of colored products, in addition to above-mentioned pigment varieties, it is more suitable to use solvent dyes and disperse dyes with high solubility to make them soluble in coloring process. A stable molecular solution is formed in plastics, showing high tinting strength, such as Macrolex series dyes (By), varieties are MacrolexYellow 6G, Yellow G, Yellow R, Orange GG, Red GS, Red 5B, Red 7B, Violet R, Violet 3R , Violet B, Green 5B, their dosage is 0.025% ~ 0.05%, and heat resistance can reach 280 ~ 300 ℃.

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