Printable Electronics Inks
Printed electronics are electrical devices that have been made by using printing processes to apply functional (conductive) coatings onto various substrates. can be thin, flexible circuits produced at highvolume and low cost. A wide range of potential applications for printed electronics and printed functionalities are under development and many companies are working on the industrialization of these applications, trying to incorporate more functionalities in smaller devices for reduced cost.
There are various printable electronic materials but for our main focus area, Printable inks we can differentiate between Conductive, Resistive, Dielectric and Electrode inks. Conductive inks are filled with silver, carbon and other conductive pigments for circuit, switch and antenna printing. Resistive inks are based on blends of silver, carbon and non-conductive pigments to adjust resistance levels for printed resistors, potentiometers and heating elements. Dielectric inks are used for printing dielectric layers, conformal coatings and encapsulations. And finally, Electrode inks are based on silver/silver chloride for biosensors, ECG electrodes and transdermal drug delivery.
These inks for printable electronics can be used on a variety of substrates such as plastic foils, PCB materials, paper and cardboard, glass and ceramic and textile. The selection of the substrate can limit product usage due to solvent sensitivity, temperature limitations and compatibility. Therefore product performance on the substrate and product/process compatibility with the substrate need to be checked beforehand.
LOCTITE ECI1011 E&C
- Highly Conductive Ink
- Screen and Flexo printable
- Paper and PET substrates
- 12 weeks
LOCTITE ABLESTIK EMI 3620FA
- Compartment EMI Shielding
- No popcorning and delamination
- For gap, hole and trench filling
- 12 weeks
LOCTITE ABLESTIK EMI 8660S
- Conformal EMI shielding
- Excellent adhesion on EMC, Au, Ag
- Spray, Print, Dispense
- 12 weeks
LOCTITE EDAG 725A(6S54) E&C
- Print Conductive circuits
- No thinning required
- Excellent adhesion
- 12 weeks
LOCTITE EDAG PF 021 E&C
- Encapsulating Photopolymer
- Prevents Silver migration
- Fast UV Cure
- Not Available
Product Selector Guide
Product | Description | Viscosity (mPAs) | Density (g/cm3) | Cure Type | Cure Schedule | Process | Substrates | Application |
---|---|---|---|---|---|---|---|---|
ECI 1011 | Highly conductive silver ink for thinner lines | 2,800 | 3 | Heat | 10min @150°C | Screen print and Flexographic | Paper, PET | Smartcard, Flexible switches, RFID |
EDAG 725A(6S54) | Conductive ink that requires no thinning | 12,500 | 2.14 | Heat | 15min @120°C | - | PET films | Membrane keyboards, membrane touch switches |
EDAG PF 021 | Encapsulating photopolymer that prevents silver migration | 11,500 | - | UV | 0.4-1 J/cm2 | - | - | Protect low profile SMD |
EDAG PF 407A | Carbon filled ink for contact areas | 35,000 | 1.12 | Heat | 30min @90°C | Stencil Print | PET, Polyimide, Paper, Carboard | Resistors, Membrane switches, heating elements |
EDAG PF 455B | Dielectric crossover with excellent adhesion | 13,500 | 1.02 | UV | 80 W/cm | - | - | Insulating crossover in assembly ops |
EDAG PF 455BC | Translucent dielectric crossover | 13,500 | 1.02 | 80 W/cm | - | PET | Compatible with EDAG and Dielectric thick inks |
Frequently Asked Questions
Can I really make a printed antenna?
Yes. An antenna is an electrical device which converts radio waves in an AC current and vice versa. Therefore an antenna needs to be conductive. Our silver inks in combination with dielectric inks (crossovers) can be used for printing HF, UHF and other antennae for RFID cards and labels.
The same conductive materials can be used for printing automotive, telephone and other antennae.
How do formable inks work?
The electronic circuitry is printed onto the flat substrate in one or multiple layers by screen printing and then components are mounted on the printed substrate. Afterwards, the flat substrate is thermoformed by either vacuum thermoforming or mechanical thermoforming creating the circuit form.
Then injection molding is used to put the plastic in place and result in the final product. Injection molding is a manufacturing process for producing parts by injecting plastic into a mold.
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Process and Application methods
There are various ways to apply printable inks. The main ones are:
- Rotogravure printing
- Flexographic printing
- Screen printing
They all come with their pros and cons and usually these are in terms of design flexibility, printing speed, quality, thickness and cost.
The advantage of screen printing is the ability to apply thick layers (5-25 µm) when compared to rotogravure or flexographic processes that can apply 1-2um in one print pass. On the other hand flat bed screen printing is much slower than flexography or rotogravure. So it all comes down to your needs to strike a perfect balance. There is also stencil printing but that is a more "simplistic" solution for dots and lines and won't be discussed here.
Rotogravure printing
Flexographic and Rotogravure printing are high speed printing processes using Anilox or Gravure rolls to control the amount of applied ink.
Rotogravure works on the principle of vacuum printing. There is a metal hole with the required image on it which passes through an inkpad. A doctor blade scrapes the ink from the roll's surface and just leaves the ink in the metal image. This ink image is then pressed against the substrate and the impression cylinder creating the final printed result.
As we will explain later, rotographic printing is a direct and really stiff (not flexible) process. In order to change the design you need to spend a significant amount of money to adjust your equipment. Having said that, this type of printing, even though non flexible, admittedly prints much better than the flexographic process. It is recommended for "standard" designs when you know you will have a specific design that will not need to change often.