What additives are used in screen printing?
Date: Oct 31 2024 From: Star Color
Screen printing involves the use of various assistants, which play crucial roles in ink formulation, printing performance, and print quality. Below is a detailed explanation of the commonly used assistants in screen printing:
- Thickener:
- Function: Increases the viscosity of the ink system, reducing its fluidity and the settlement of solid components.
- Application: Often used in ink systems requiring high viscosity, such as in the textile printing and dyeing industry.
- Advantages: Adding a small amount can significantly increase viscosity, allowing the ink to better penetrate into textiles, achieve uniform sizing, and prevent splashing and sagging.
- Thinner:
- Function: Improves the viscosity and fluidity of ink or printing paste.
- Classification: Divided into standard, fast-drying, and slow-drying types, with different formulations selected based on ink type and temperature.
- Main Components: Cyclohexanone, xylene, butyl acetate, etc.
- Viscosity Reducer:
- Function: Reduces the viscosity of ink, improves fluidity, avoids stringing, and maintains ink drying speed and gloss.
- Addition Amount: Generally 3%-5% of the ink, with excessive amounts reducing ink performance and printability.
- Drying Agent:
- Function: Accelerates ink drying.
- Classification: Oxidative drying agents (e.g., cobalt dryer, manganese dryer) and polymeric drying agents (e.g., lead dryer).
- Drying Speed: Cobalt dryer is the fastest, manganese dryer is medium, and lead dryer is the slowest.
- Plasticizer:
- Function: Makes the ink film flexible, especially effective for volatile drying inks.
- Application: Often used in volatile drying inks such as nitrocellulose binder inks, oil-based inks, and water-based inks.
- Precautions: Excessive addition can soften the resin.
- Defoamer:
- Function: Eliminates bubbles in ink, preventing printing defects.
- Classification: Silicon-based and non-silicon-based, with silicon-based being widely used.
- Precautions: Excessive amounts can lead to poor ink adhesion.
- Dispersant:
- Function: Promotes the dispersion of pigments in the binder.
- Leveling Agent:
- Function: Improves the smoothness of screen printing ink.
- Adhesion Promoter:
- Function: Enhances the adhesion of screen printing ink.
- Color Separator:
- Function: Prevents ink separation when using two or more pigments in a single ink.
- Sedimentation Preventer:
- Function: Prevents pigment settlement during storage when the pigment has a high specific gravity in the ink.
- Antistatic Agent:
- Function: Eliminates static charges generated during screen printing.
- Coupling Agent:
- Function: Improves ink adhesion properties, especially useful for substrates where ink adhesion is difficult, such as glass.
In summary, a wide variety of assistants are used in screen printing, each with its specific function and purpose. In practical applications, factors such as ink type, substrate material, and printing speed must be considered comprehensively to select the appropriate assistants for optimal printing results.
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