Epoxy resin is a general term for a chemical compound containing two or more epoxy groups in a molecular structure and capable of forming a three-dimensional network-like cured product in the presence of a suitable chemical agent, and is a type of thermosetting resin which is widely used. Since the molecular structure contains more side chain hydroxyl groups, it gives higher reactivity and adhesion, which provides a broad application prospect for epoxy resin application. However, due to the high rigidity of the cured epoxy resin, it is easy to crack after curing, so the toughening of epoxy resin has always been the focus of product development.
    In order to make full use of the adhesion and insulation of epoxy resin, we have developed a low-hardness and low-stress epoxy potting compound that can be cured at room temperature. The product has low hardness and flexibility, and has a low shrinkage during curing. It is suitable for motor or electronic potting.
Table 1 Performance indicators of low hardness and low stress epoxy potting adhesive at room temperature
Test items
unit
Numerical value
solid
Chemical
before
Component


Component A
Component B
colour
/
Red fluid
Yellow liquid
Viscosity
 mPa·s
8,000 to 10,000
10-20
density
g/cm3
1.47~1.51
0.92~0.98
mixing ratio
(mass ratio)
/
5
1
Mixed viscosity
mPa·s
3,000 to 4,000
Dry time
h
3.5 to 4 (25 ° C, 150 g)
Full cure time
h
36 (25 ° C)
Or after drying 3 (80 ° C)
solid
Chemical
Rear
colour
/
Red flexible solid
density
g/cm3
1.40~1.44
hardness
Shore A
52~54
Glass transition temperature
°C
-13.5~-11.5
82.0~90.0
Tensile Strength
MPa
>3.0
Elongation at break
%
>50
Thermal conductivity
W/mk
>0.6
Breakdown strength
kV/mm
>22
Water absorption rate
%
24h: 0.48
168h: 0.99
Neutral salt spray
h
No significant change in 1000h sample
Volume resistivity
Ω.cm
>1013
Thermal expansion coefficient
Mm/(m.°C)
140～160
    Through the above product performance data, it can be found that the product has low hardness and environmental resistance. In order to verify the potting effect of the product, a simulation experiment was carried out, as shown in the figure below.


Figure 1 product potting effect
Test 1: The test conditions are as follows
Stage 1: low temperature -55 ° C / 4 h;
Stage 2: high temperature 135 ° C / 4 h;
High and low temperature conversion time is not more than 10min.
   For 12 cycles, each cycle was examined for appearance, discoloration, cracking, and interface bonding changes. After testing, the silicone potting glue passed the thermal shock of up to 135 ° C and the lowest -55 ° C, the appearance color did not change significantly, and the interface between the glue and the substrate did not change significantly.
Experiment 2: The test conditions are as follows
Stage 1: low temperature -55 ° C / 4 h;
Stage 2: high temperature 135 ° C / 4 h;
Stage 3: immersion in water for 6 hours at room temperature;
High and low temperature conversion time is not more than 10min.
   For 12 cycles, each cycle was examined for appearance, discoloration, cracking, and interface bonding changes. After testing, the silicone potting glue passed the environment experiment with the highest 135 ° C, the lowest -55 ° C and the water immersion, the appearance color did not change significantly, and the interface between the glue and the substrate did not change significantly.


Figure 2 A certain type of motor coil for product potting
发送反馈
历史记录