Dry-Pack

The antistatic, water-vapour impermeable, flexible packaging for electronic components. DRY-PACK bags offer optimum protection against moisture damage. They contribute towards preventing the popcorn effect in SMD technology. They also offer perfect corrosion protection, both for long-term packaging in a warehouse and for export to the most remote regions and most extreme climatic zones.

Three parts form the prerequisites for a functional DRY-PACK package:

the antistatic, water-vapour impermeable, flexible barrier film = DRY-PACK foil,
the right size of desiccant bag acc. to DIN 55473, and
the special SMD HUMITECTOR humidity indicator card with an indication range of 10%, 20%, 30% and 40% RH.

The proper use of the above-mentioned packing prerequisites and careful processing will guarantee protection from moisture and corrosion.

Description

The antistatic, water-vapour impermeable, flexible barrier films are produced as multi-layer composite or combination foils. The flat bag is the usual retail format.

We keep a variety of dimensions in stock. We can also supply flat bags to your dimensions.

Structure of the DRY-PACK foil (from the outside to the inside):

antistatic polyethylene foil,
aluminium foil,
polyethylene foil,
aluminium foil,
antistatic low-density polyethylene foil.

We offer two materials: Dryshield 7000 and Dryshield 7700. The difference lies in the thickness, the water-vapour permeability and the puncture resistance.

Physical and mechanical properties

	Dryshield 7000	Dryshield 7700
Thickness	0,09 mm +/- 10%	0,18 mm +/- 10%
Light penetrability	Opaque structure	Opaque structure
Tensile strength	40 lbs.	45 lbs.
Tear strength	> 4,5 lbs.	> 5,0 lbs.
Stretch	none	none
Burst strength	> 50 psi.	> 50 psi.
Puncture resistance	> 20 lbs.	> 30 lbs.
Heat-sealing resistance	> 12 lbs	> 12 lbs.
water-vapour permeability	< 0,32 g/m2 / 24 h	< 0,085 g/m2 / 24 h

Electrical properties

	Dryshield 7000	Dryshield 7700
surface resistance of inner and outer layers von	<10^11 Ohm	<10^11 Ohm
resistance of Aluminium layer	100 Ohm	100 Ohm
static decay time	<0,03 sec.	<0,03 sec.
ESD-Shielding	< 10 nJ.	< 10 nJ.
EMI attenuation	45 dB.	45dB.
meets or exceeds	IEC 61340-5-1	IEC 61340-5-1
	MIL PRF-81705D, Type I, Class I	MIL PRF-81705D, Type I, Class I
	EIA 583	EIA 583

Stocked sizes

Other sizes are available on request!
Part-No.	Material	Size
SC701020	Dryshield 7000	254x508mm	10"x20"
SC701030	Dryshield 7000	254x762mm	10"x30"
SC701618	Dryshield 7000	406x457mm	16"x18"
SC77140680	Dryshield 7700	140x680mm
SC770155700	Dryshield 7700	155x700mm
SC77203406	Dryshield 7700	203x406mm	8"x16"
SC77254457	Dryshield 7700	254x457mm	10"x18"
SC771020	Dryshield 7700	254x508mm	10"x20"
SC771030	Dryshield 7700	254x762mm	10"x30"
SC771618	Dryshield 7700	406x457mm	16"x18"
SC771719	Dryshield 7700	432x483mm	17"x19"

The following materials are unsuitable for DRY-PACK packing:

electrically conductive black polyethylene foils,
antistatic pink polyethylene foils,
STATIC-SHIELDING foils.

The thickness of these foils is between 75 – 150 microns. Their water-vapour permeability is therefore several times higher than that of the special DRY-PACK foils.

Desiccant

The desiccant bag should meet DIN 55473, which defines the size of a desiccant unit not by weight but by the desiccant’s ability to absorb/adsorb water vapour:

A “desiccant unit” is that quantity of desiccant, as received, which at equilibrium with air  at 23°C (± 2°) and a relative humidity of 20% adsorbs at least 3 grams of water vapour,  and at a relative humidity of 40% at least 6 grams of water vapour.

We offer appropriate desiccants and would be pleased to calculate the amount of desiccant you need per package.

Humidity indicators

The SMD HUMITECTOR humidity indicator cards were specially developed for the DRY-PACK. Its indicator range extends from 10%, through 20% and 30%, to 40% relative humidity (RH). It has a colour comparison field with whose help the RH can be very simply determined.

The SMD HUMITECTOR is reversible, i.e. it always shows the RH present at the moment of observation. The indicator points of the humidity indicator are blue when the RH lies below the figure printed on the humidity indicator. They change colour to pink when the RH exceeds this percentage amount.

So when monitoring DRY-PACK packages, the humidity indicator should always be read immediately after opening of the barrier bag. The indicators below 30% RH react very quickly to significantly higher humidities. The colour change from blue (= lower RH) to pink (= higher RH) takes place rapidly.

Packaging

The desiccant bag and the humidity indicator are placed in the DRY-PACK together with the component(s). The antistatic, water-vapour impermeable and flexible DRY-PACK bag is now closed with a suitable heat sealing device. The desiccant absorbs most of the water vapour contained within the bag. The relative humidity is reduced to about 5%.

It is recommended that air is suctioned out of the DRY-PACK bag until the foil is in contact with the packed object(s). This reduces the volume of the package and simplifies any intended stacking. One should avoid too great a suction of air, however, because of the risk of bending, or even breaking, very sensitive parts. The foil could also be damaged by being dragged over corners and edges.