DENATRON Museum / Get to know DENATRON
Conductive Coatings for Screen-Printing, DENATRON
HOME > DENATRON Museum > Get to know DENATRON > Conductive Coatings for Screen-Printing, DENATRON
What is DENATRON?
DENATRON is a conductive coatings available in two types: Type-P, which is based on the conductive polymer PEDOT:PSS, and Type-C, which is based on carbon nanotube (CNT).
It is intended for applications such as transparent electrodes and Antistatic purposes, with different types used depending on specific requirements. Among the DENATRON Type-P products, there are versions designed for screen printing, specifically for use in transparent electrodes for touch panels and electrodes for biosensors.
Applications of DENATRON
Electrodes for Touch Panels and Touch Switches
The film formed by DENATRON for screen printing offers greater design flexibility compared to metal-sputtered ITO films. One key advantage is its ability to be used on curved or spherical surfaces, where ITO films would typically crack. Additionally, since it provides sufficient conductivity with a thin film of approximately 0.03 μm, it can be applied in areas with limited space where using a touch switch might otherwise be cost-prohibitive.
Learn more
Electrodes for Biosensors
DENATRON is a conductive coatings with hydrophilic and biocompatible properties. It can be applied to sensors that come into direct contact with the skin without the risk of causing metal allergies. This is due to the use of PEDOT:PSS as a raw material, and experiments using animal (rodent) cells have confirmed that no cytotoxic reactions occur.*1
Learn more
Conductive Layers for OLED Devices
Organic Light Emitting Diode (OLED) Devices is used in various applications, including smartphones and large displays. DENATRON is suitable for use on curved surfaces, making it compatible with conductive layers in foldable smartphones and other flexible displays. Additionally, if a switch is required on the display, DENATRON can be used as an electrode to create 3D-printed switches.
Learn more
Features of DENATRON
-
High Transparency
DENATRON exhibits high transparency when a film is formed. This is due to its minimal absorption in the visible light range and its ability to be used as a thin film. This makes it highly effective in providing the required conductivity without compromising the appearance of the coated product.
-
Wide Range of Applications
In addition to conductivity, DENATRON can be used for a wide range of applications, such as Antistatic (static electricity prevention). This is due to its broad Sheet Resistance range (102–1010 Ω/sq.). Sheet Resistance refers to the resistance value per unit area, and the level of conductivity can be adjusted based on the application, from conductive (around 102 Ω/sq.) to less conductive (around 1010 Ω/sq.).
-
Excellent Processability
DENATRON can be printed on various objects using methods such as gravure printing (intaglio printing) and screen printing. Additionally, it allows for bending and stretching after the film is formed, maintaining conductivity even when applied to deformable materials such as rubber or thin films.
-
High Biocompatibility
DENATRON has high biocompatibility and is less likely to cause skin issues, even when used in sensors that come into direct contact with the skin. PEDOT:PSS, the raw material of DENATRON, is known as an acidic material with no cytotoxicity or skin irritation, and is therefore biocompatible and used in sensors that are directly attached to the skin.*1
How to Screen Print DENATRON
Printing Procedure
1. Set the DENATRON on a screen plate (stencil) with mesh openings according to the desired printing pattern.
2. Print DENATRON onto the film as it passes through the mesh openings of the screen plate.
3. Use a blow dryer to dry the film at 80℃–140℃.
For more details, please watch the video above.
Recommended Product
The DENATRON series offers a variety of products suited for different applications. Here, we introduce a product that is ideal for screen printing.
SP-801
DENATRON SP-801 is a conductive coating compatible with screen printing. It uses a conductive polymer (PEDOT:PSS), providing high transparency and low electrical resistance. SP-801 is a paste-like coating. Table 1 shows the liquid properties of SP-801.
| Appearance | Dark blue color |
|---|---|
| Main Components | Conductive material, binder resin, Additive |
| Main Solvent | Water-based solvent |
| pH | 2–3 |
| Viscosity | 1,000–3,000 mPa·s |
| Storage stability (1℃–10℃) | More than 6 months |
Table 1. Liquid Properties of SP-801
Although the paste appears dark blue before application, it becomes transparent after being applied, and a film is formed. The water-based solvents used are solvents with characteristics that dissolve organic compounds such as resins, but have low toxicity. Additionally, it has a viscosity suitable for screen printing, where the paste is extruded from the slit using a squeegee. When stored under appropriate conditions, it can be kept for over 6 months.
To print DENATRON on the substrate, first thoroughly stir it using a dispersion mixer (around 1,500 rpm for about 10 minutes). Afterward, set it up in a screen-printing machine for printing. Please refer to the recommended film formation conditions shown in Table 2.
| Recommended Coating Conditions | Squeegee hardness: 70–80°, Squeegee angle: 50–80° |
|---|---|
| Speed | 200–350 mm/s, Clearance: 2–4 mm |
| Mesh | #200–460 |
| Recommended Substrate | Plastics such as PET, PMMA (acrylic resin), PC, or glass |
| Recommended Drying Conditions | Temperature: 80°C–120°C, Drying time: 1–5 minutes |
Table 2. Film Formation Conditions
Basics of Conductive Coatings (Conductive Paints) for Screen-Printing
What is Conductive Coatings (Conductive Paints)?
Conductive coatings (conductive paints) is a special coating that has the property of conducting electricity. It contains conductive fine particles, such as metals or carbons, and once the film dries, it can conduct electricity. This makes it valuable in the manufacturing of various electronic components and devices. By using screen printing technology, precise patterns and circuits can be created, contributing to the miniaturization and improvement of electronic devices.
Materials Used in Conductive Coating
Once limited to specific applications like ATMs, touch panels have now become a familiar part of our daily lives, and are used in smartphones, tablets, and more. Additionally, as physical switches on automotive instrument panels (center panels) decrease, touch switches—allowing switching simply by touching the surface—are becoming more prevalent.
Touch panels require various properties depending on their application, and corresponding materials are selected. Below are some representative materials used for electrodes in touch panels:
PEDOT:PSS
PEDOT:PSS is a conductive polymer that is easy to use by simply evaporating the solvent, making it suitable for films with a heat resistance of around 70℃. Although there have been concerns about its durability compared to other materials, advancements in blending technologies have improved its durability, making it comparable to other materials.
Its smoothness is relatively high but can also be enhanced with blending technology. It is notable for being suitable for large areas and adapting to shape changes. In terms of conductivity and transparency, it is on par with other materials.
Carbon Inks
Carbon inks can be divided into CNT and carbon black. Both are characterized by high conductivity and light resistance. However, there is a difference between the two: CNT are known to have higher conductivity. CNT tend to agglomerate, but their conductivity can be adjusted by proper dispersion. There are single-walled CNT and multi-walled CNT. Selecting the optimal carbon depends on conductivity and cost.
Silver Nanowires
Silver nanowires are conductive materials made from silver nanowires. They offer good conductivity and flexibility, and aside from slightly lower durability and smoothness, they share properties similar to those of PEDOT:PSS. They are also suitable for large areas and adapting to shape changes.
However, because silver nanowires need to adhere to each other, high-temperature treatment or pressure is required. Additionally, if the overcoat is too thin, there is a risk that the sharp ends of the wires may damage the film.
Silver Mesh
Silver mesh is a material woven into a mesh shape using silver, which is known for its high conductivity, high transparency, and flexibility. It is also durable and suitable for large areas while being adaptable to shape changes. However, due to the height of the cross-points (woven areas) in the mesh, it tends to have lower flatness and smoothness, which may not be ideal for devices that require a smooth surface feel.
Inquiry/Sample request
Nagase ChemteX Corporation partners with customers in product development and quality improvement, offering optimal conductive solutions. We look forward to your inquiries regarding the selection of conductive paints.
Inquiry/Sample request
Reference
*1：Biomed. Mater. 4 (2009) 045009, M Asplund et al.
Return to list of articles