Thermosetting Polymer SMT-Adhesive for Printing Application
Description
PD 955 PY and PR are thermosetting single-component, solvent-free polymer adhesives, developed especially for the surface mounting of SMT components on to PCBs and for use on bare substrates.
The rheology is especially adapted for printing application with thick stencils.
The difference between PY and PR version is in colour only.
Special advantages
- Ideal, high dot form and excellent consistency of the glue dots.
- Specially developed for printing with thick stencils.
- Very high green strength prevents component movement during placement.
- Form stable glue dots.
- Excellent adhesion with standard and also with difficult-to-glue components.
- Very low humidity absorption. Steep temperature increases and very short curing times are possible without danger of formation of air bubbles or worse adhesion.
- High surface insulation resistance (SIR).
Physical characteristics
Colour
PD 955 PY yellow
PD 955 PR red
Density: 1.2 g/cc
Homogeneity: no particle >50 µm
Adhesion: ≥ 25 N/mm2 at room temperature, after curing in conventional box oven, 5 min /125°C, Cu-nail on SO component, with a low-stress incapsulation compound.
Cone / plate, without border, 2° cone, temperature: 23°C.
Processing
The adhesive is suitable for printing with metal and plastic stencils.
Curing
The standard curing conditions are: 125°C / 3’. Max. curing temperature should not be higher than 200°C. The minimum* curing times are shown in the following list.
100 °C
|
125 °C
|
150 °C
|
180 °C
|
8 '
|
3 '
|
1.5 '
|
1 '
|
∗ Optimal curing conditions depend on the curing oven.
Cleaning
Before curing:
The uncured adhesive can be removed with alcohol or water based cleaning materials. Please contact your local representative for specific recommendations.
The cleaned parts must be completely dry before installing them in the machine.
In order to avoid an attack of the cleaning medium on the stencil frame adhesive it is recommended to perform trials before use in volume production.
After curing:
Because of the known residual thermoplasticity of the cured adhesive, defective components can be easily replaced by heating (with hot air) the cured adhesive joint above 100°C. After removing the component (torsion movement), the hot air should be focused on the remaining adhesive in order to remove it with a sharp tool.
Storage
Storage time: 6 months in a refrigerator, at a storage temperature of 5 - 12°C.
Remark: Storage at temperatures >30°C should be avoided.
