Silver-containing conductive preparations of DODUCO GmbH

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Decades of experience in the area of production of silver-pigmented conductive preparations and close cooperation with the customer have enabled DODUCO to develop general and special problem solutions according to the customer's wish. This way, different conductive products resulted, the properties of which have been adjusted to different requirements.

 

DODUCO's range of precious-metal-containing (silver-pigmented) conductive preparations includes:

 

Silver conductive varnishes Silver conductive paste

 

The products are available exclusively in 1kg bottles.

 

 

Silver conductive varnishes

DODUCO's silver-pigmented conductive varnishes are liquid, solvent-containing, physically drying varnishes. Depending on the area of application (carrier material, drying requirements), there are mostly two types distinguished:

• Conductive varnishes on acrylate-resin basis and
• Conductive varnishes on nitrocellulose basis

At a silver share of approx. 40 % silver (exceptions are possible) in the form of silver powder or silver flakes from own production, DODUCO's silver conductive varnishes are characterised by high electrical conductivities at low viscosities. The liquid conductive varnishes can be applied to the carrier materials by brush, roller or submersion. If a spray application is desired, the conductive varnish should be mixed with the corresponding diluent (information on the diluent is available on request). Drying takes place by evaporation of the solvents contained in the temperature range between 20-100°C (on demand, higher temperatures are possible as well).

 

DODUCO's product range currently contains the following conductive varnishes:

 

 

AUROMAL® 38
Base	Acrylate resin
silver-content	40 %
Viscosity	40-50 mPas
Surface resistance	400 mOhm/cm² at RT   < 100 mOhm/cm² at 100°C
Properties/use	hard, well-conductive silver layer

 

AUROMAL® 50
Base	Nitrocellulose
silver-content	45 %
Viscosity	30-50 mPas
Surface resistance	< 200 mOhm/cm² at RT < 50 mOhm/cm² at 100°C
Properties/use	Level surface, particularly suitable for galvanic reinforcement

 

AUROMAL® 50L
Base	Nitrocellulose
silver-content	45 %
Viscosity	50-70 mPas
Surface resistance	< 200 mOhm/cm² at RT < 50 mOhm/cm² at 100°C
Properties/use	Hard, well-conductive silver layer, suitable for galvanic reinforcement

 

 

The benefit of the silver conductive varnishes as compared to the pastes is in simple processing and quick drying. Furthermore, they have a strong, good adhesion to the base and very good electrical and thermal conductivity.

 

DODUCO's silver-pigmented conductive varnishes are used in:

• shielding of electromagnetic waves in the area of electrical engineering and electronics
• Production of a contact in the area of electrical engineering and/or hobby electronics (e.g. electronic toys)
• Repair of conductor tracks / improvement of printed circuits
• Repair of heating conductors (rear window heatings)
• Repair of antennas
• Metallisation of non-conductive bases for galvanic further processing

 

Silver conductive paste

The also physically drying silver-pigmented conductive paste of DODUCO have a much higher viscosity than the conductive varnishes. This is caused by higher shares of silver (approx. 60%) and use of polymer basic components for formation of polymer compounds / design of the polymer structure. The silver used in the silver conductive paste in the form of silver powder or silver flakes is also from the DODUCO-internal production.

 

The silver-pigmented polymer thick-film paste are characterised by good electrical and thermal conductivity as well as good adhesion and bending resistance while being highly flexible. The application of conductive paste preferably takes place by screen printing, with selection of the mesh size varying depending on printing pattern, layer thickness and base. Drying and curing may take place in circulation air dryers, IR-dryers or special tunnel furnaces.

On remand, the silver-pigmented conductive paste can also be adjusted to different processing techniques (e.g. pad printing). The chemicals required for this may be purchased from DODUCO on request.

 

AUROMAL® 141
Base	Acrylate resin
silver-content	63 %
Viscosity	1,5-3,0 Pas
Surface resistance	< 50 mOhm/cm² at 150°C
Properties/use	Mechanically high-strength coatings with very good conductivity, Good adhesion on plastic

 

 

The benefit of silver conductive paste as compared to the varnishes is in the better adhesion to plastic bases as well as films. I spite of high demands by increased flexibility, the layers remain stable and retain their very good conductivity.

 

 

DODUCO's silver-pigmented conductive paste are used in:

• production of conductor tracks on membrane keyboards
• production of circuits on PCBs