Certain plastic encapsulated surface mount devices (SMDs), if not handled properly, can incur damage during the solder reflow attachment process to printed circuit boards (PCBs). In order to prevent damages, the moisture sensitive product is typically baked before packing. After baking, the product is placed inside a DryPack bag along with predetermined amount of desiccant and a humidity sensitive indicator card (refer to JEDEC J-STD-033C). The vacuum sealed bag is labeled and placed in a pizza box carton.
Moisture Barrier Bags, MBB
MBB are designed to protect components against
- electrostatic charge
- electromagnetic fields
|Material code||Thickness||MVTR 100 in2 / 24 h (nach ASTM-D-1249)|
|DY3008-652||91 µm||< 0.02 g|
|DY3008-106||152 µm||< 0.0003 g|
Electrical and physical properties are complying with the standards EIA-583, EIA-541, EIA-625, and MIL-PRF-81705 type 1. In order to meet JEDEC J-STD-033C, we recommend material DY3008-106.
Bags with a Moisture and ESD Logo
|K-TECH p/n||Material code||Inner dimension in mm||Application|
|K05204||DY3008-106||400 x 480||13″|
|K05211||DY3008-106||254 x 710||IC|
|K05217||DY3008-106||254 x 500||Trays|
Many other sizes are available from stock. Custom sizes and custom printing can be done on request.
For further information please contact K-TECH or visit the website of our supplier DOU YEE.
Bentonite clay is a natural mineral and has a layer-shaped construction. The moisture is absorbed between these layers. Bentonite clay is an economic solution for temperatures up to 50 °C. When temperatures rise above 50 °C, benonite clay releases the moisture it has absorbed back to the air. With baking at a temperature of 120 °C, this desiccant can be reactivated to be reused.
Zeolite molecular sieves are crystalline, highly porous materials, which belong to the class of aluminosilicates. As part of the manufacturing process, the pore size on the molecular sieve particles can be controlled. This allows a selective adsorption of a wide range of organic molecules as well as moisture.
Molecular sieves properties differ from clay and silica gel in a number of ways:
- They adsorb moisture more rapidly.
- They will reduce moisture to much lower levels, making their use essential when a very dry product or atmosphere is required.
- They perform more effectively as moisture adsorbers at higher temperatures.
|Adsorptive capacity at low concentrations||excellent||fair|
|Adsorptive capacity for water 25 °C, 40 % RH||high||medium|
|Adsorptive capacity at high temperatures||high||poor|
|Separation by molecular sizes||yes||no|
The German standard DIN 55473 only allows for the description in desiccant units. One desiccant unit is equal to the amount of a drying agent capable of adsorbing a minimum of 6 g at 40 % relative humidity of water vapor at an air temperature of 23 °C (±2).
All desiccant manufacturing by Dou Yee is compliance to JEDEC J-STD-033 and MIL-D-3464 standard.
Indicator Cards (HIC)
A humidity indicator card (HIC) is a card on which a moisture-sensitive chemical is impregnated such that it will change color when the indicated relative humidity is exceeded. This is an economical way to quantify relative humidity levels inside sealed packaging like moisture barrier bags.
An overview of our humidity indicator cards you can find here (German).
Corrugated card board 1.30b
Standard sizes available from stock:
- Type 1: 340 x 340 x 31
- Type 2: 340 x 340 x 41
- Type 3: 340 x 340 x 53
(all dimensions in mm)