CAS No. 5601-29-6 Ink Leather Paint Dyestuff Solvent

Product Description

Product Description
 

Solvent dyes are a type of dye that is insoluble in water but soluble in organic solvents (such as alcohols, esters, hydrocarbons, etc.). They are mainly used for coloring non-polar or weakly polar substrates. Their product properties can be described in detail from aspects of chemical properties, physical properties, dyeing performance, etc. as follows:

 

1. Chemical Properties
   Chemical Structure
   Molecules usually do not contain water-soluble groups (such as sulfonic acid groups, carboxyl groups, etc.), but are mainly composed of hydrophobic groups (such as alkyl, aryl, alkoxy groups, etc.). Therefore, they are insoluble in water but can combine with organic solvents through van der Waals forces and hydrophobic interactions to achieve dissolution.
   The chromophoric systems are diverse, including azo, anthraquinone, phthalocyanine, and triphenylmethane types, among which azo and anthraquinone types account for the highest proportion. The molecular structure contains chromophores such as azo groups (-N=N-) and anthraquinone rings, which impart bright and diverse colors (such as red, yellow, blue, purple, black, etc.) to the dye through the conjugated system.
   The molecular weight is medium to large (generally between 300-1000), and the molecular structure is non-polar or weakly polar, which has good compatibility with non-polar substrates (such as plastics, oils, waxes, etc.) and can be uniformly dispersed and colored through intermolecular forces.

 

Chemical Stability
They have good stability to acids and alkalis, and are not prone to hydrolysis or structural damage within a wide pH range (usually pH 3-11), making them suitable for use in various chemical environments.
The oxidation resistance and reduction resistance vary by structure: anthraquinone and phthalocyanine solvent dyes have strong oxidation resistance; azo types are more sensitive to strong oxidants, and the chromophores may break, leading to fading; most solvent dyes have better stability to reducing agents than direct dyes or acid dyes.
Some solvent dyes (such as metal complex types) contain metal ions (such as copper, nickel), which can enhance molecular stability and light fastness.

 

1. Physical Properties
   Appearance
   Most are powdery, granular, or crystalline, with high color brightness and pure hue. In particular, anthraquinone and phthalocyanine solvent dyes have more vivid hues (such as bright blue, etc.).
   The color spectrum is complete, covering almost all colors from light colors (such as yellow, orange) to dark colors (such as blue, black). Among them, solvent black, solvent red, and solvent yellow are the most commonly used varieties.

 

Solubility
The core characteristic is insolubility in water, but they are easily soluble in specific organic solvents:
Low-polarity solvent dyes (e.g., for hydrocarbon solvents) can dissolve in hydrocarbons;
Medium-polarity solvent dyes can dissolve in ethanol, etc.;
High-polarity solvent dyes (rare) can dissolve in strong polar solvents such as ethylene glycol and dimethylformamide (DMF).
Solubility increases with temperature, and some varieties can form stable organic solutions at high temperatures, which are not easy to precipitate after cooling.

 

Other Physical Properties
The melting point is relatively high (usually between 150-300°C), and some crystalline solvent dyes have a definite melting point;
The density is generally 1.2-1.6 g/cm³, depending on the molecular structure and substituents;
They have good thermal stability and are not easy to decompose at processing temperatures (such as plastic molding temperature of 100-250°C), making them suitable for high-temperature coloring processes.

 

1. Dyeing Performance
   Applicable Substrates
   Mainly used for coloring water-insoluble, non-polar, or weakly polar materials, including:
   Plastics (polyethylene, polypropylene, polystyrene, ABS resin, etc.);
   Oils and waxes (cosmetics, candles, shoe polish, etc.);
   Organic solvent-based coatings and inks (lacquers, alkyd paints, printing inks, etc.);
   Dope dyeing or solvent dyeing of synthetic fibers (polyester, nylon, etc.);
   Solvent-based colorants for wood and leather.

 

Coloring Methods
Dissolution and dispersion: Dissolve the dye in the corresponding organic solvent, then mix it with the substrate to be colored, and allow the dye to be evenly distributed in the substrate through the penetration or volatilization of the solvent;
Melt mixing: For thermoplastic materials such as plastics, the dye can be directly mixed with molten resin, and the dye molecules can diffuse into the resin with the help of high temperature;
No fixation treatment required: Since the dye is closely combined with the substrate through intermolecular forces, it is not easy to fall off after coloring, and the color fastness mainly depends on the compatibility between the dye and the substrate.

 

Color Fastness
Light fastness: Anthraquinone and phthalocyanine solvent dyes have excellent light fastness (up to 4-5 grades), suitable for products used outdoors; azo types have moderate light fastness (3-4 grades), and some varieties can be upgraded to 4 grades through molecular modification (such as introducing halogen atoms).
Migration fastness: One of the key properties, referring to whether the dye diffuses and migrates in the substrate or when different substrates are in contact. Solvent dyes with good compatibility with the substrate (such as special dyes matching the plastic type) have strong migration fastness (4-5 grades), while those with poor compatibility are prone to "bleeding" (2-3 grades).
Heat resistance: Most can withstand processing temperatures of 150-250°C, meeting the requirements of plastic injection molding, extrusion and other processes. A few high-temperature special varieties can have heat resistance up to 300°C or higher.

 

1. Classification and Typical Varieties

 

Type Characteristics Typical Varieties
Azo solvent dyes Wide color spectrum (mainly red, yellow, orange), low cost, moderate light fastness Solvent Yellow 14, Solvent Red 24
Anthraquinone solvent dyes Bright hue (mainly blue, purple, green), excellent light and heat resistance, high cost Solvent Blue 35, Solvent Green 3
Phthalocyanine solvent dyes Dark colors (blue, green), excellent light and weather resistance, strong tinting strength Solvent Blue 104, Solvent Green 7
Metal complex solvent dyes Containing metal ions (such as copper, chromium), high color fastness, suitable for high-demand scenarios Solvent Red 195, Solvent Yellow 93

 

Solvent dyes are widely used in industrial fields such as plastics, coatings, and inks due to their insolubility in water, good compatibility with non-polar substrates, and bright colors. When selecting, it is necessary to focus on matching the polarity of the substrate to be colored and the processing conditions to ensure coloring uniformity and color fastness.

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