Moisture Barrier Bags

Moisture Barrier Bags When storing moisture sensitive products, you need a container that keeps moisture out. While desiccants will remove excess moisture, and humidity indicator cards will let you know when to replace your desiccant, they are not much help if your bags do not provide a protected environment. By using moisture barrier bags, you can block new influxes of moisture and humidity, allowing desiccants to keep your products dry and safe.

There are many sizes of moisture barrier bags available, so you may be wondering how much desiccant you need to use. In order to figure that out you need to have some information about your application. First you need to know the standard that you want to use. There are three main standards: IPC/JEDEC J-STD-033 (dry packaging for SMD’s), EIA 583 (dry packaging for SMD’s and allows for environmental conditions), and MIL-P-116 (general dry packaging).

For IPC/JEDEC J-STD-033 the formula is:

Units= 0.304 x Storage Time in Months x Bag MVTR x Bag Area in inch2

Moisture Capacity

For EIA 583:

Choose moisture capacity based off of Maximum Interior Humidity

10%=2g/unit 20%=4.8g/unit 30%=5.8g/unit 40%=6.2g/unit

Units= 0.231 x Storage Time in Months x Bag MVTR x Bag Area in inch2

Moisture Capacity

 

For MIL-P-116:

Units= 0.011 x Bag Area in inch2

All of these formulas give you the “units” of desiccant needed. Typically desiccant pouches are measured in units, and each unit designates how much is needed at 77°F to absorb 3 grams of water vapor at 20% relative humidity or 6 grams of water vapor at 40% relative humidity. A unit of silica is smaller than a unit of clay, as silica is better at absorbing moisture.

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All-Spec Moisture Barrier Bags Design:

All-Spec Industries offers a complete line of static shielding moisture barrier bags. Our bags range in size from 3 x 5” to 20 x 24” with various thicknesses to fully protect your product without taking up too much space. All of our All-Spec brand moisture barrier bags offer full ESD, RFI, and EMI protection.

Features:

  • Amine free to prevent outgassing and corrosion
  • Heat sealable
  • May be nitrogen flushed or vacuum packed

 

Specifications:

 

  • Static dissipative inner and outer layers
  • Static shielding
  • Non-sparking
  • Moisture vapor transfer rate from <0.0003 to <0.02 using ASTM F 1249 test method
  • Puncture resistance of 17-30lbs using FTMS 101 MTH 2065 test method
  • 3.6, 4.0, 6.1, and 7.0 mil thicknesses available

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All-Spec’s Moisture Barrier Bags

by Andy on July 14, 2011

All-Spec Moisture Barrier Bag Moisture barrier bags are used to protect moisture sensitive items from damage during transport and storage. All-Spec carries different types of moisture barrier bags that offer EMI, RFI, and static shielding properties in addition to moisture protection. The added EMI, RFI and static protection makes the All-Spec bags ideal for items like surface mount devices (SMD’s), printed circuit boards (PCB’s) and any items that need to be protected from rust or corrosion.

All-Spec carries three different options of moisture barrier bags including the 60 Series, 63 Series, and 64 Series. These bags are constructed differently and thus offer slightly different specifications and features. Made from multiple layers of plastic and aluminum, All-Spec’s moisture barrier bags all offer similar EMI, RFI and static shielding properties but varying levels of puncture resistance and moisture vapor transmission rates (MVTR). The MVTR is measured using the ASTM F-1249 standard which is the amount of water in grams that will move through 100 in2 of the tested material at 100oF in a 24 hour period.

Determining which series of moisture barrier bag to use is based strictly upon your application. Based on the MVTR, thickness and puncture resistance you can choose which bag will work best for you. The 7mil bags, although more puncture resistant, can “crease” easier than the 3.6 mil bags and cause a weak area in the material, leading to potential failure. The 3.6mil bags are generally more flexible but less puncture resistant than the 7mil bags. The 6.1mil bags have the best MVTR which means that less desiccant will be required to eliminate the moisture that does get into the bag. On the other hand, they are less puncture resistant than the 7mil bags and are less flexible than the 3.6 mil bags.

Series Thickness MVTR Puncture Resistance
60 Series 3.6 mils (.0036”) MVTR – < .02 grams 21 lbs
63 Series 6.1 mils (.0061”) MVTR – < .0003 grams 21 lbs
64 Series 7.0 mils (.0070”) MVTR – < .005 grams 30 lbs

 

Humidity Indicator Card

In addition to moisture barrier bags, All-Spec Industries carries a variety of dry storage products to use during the packaging process. It is recommended that you place a humidity indicator card (HIC) and desiccant inside each bag. The desiccant absorbs the moisture that penetrates the bag and the humidity card allows the person who opens the bag to know what amount of moisture has gotten into the bag. In order for the bag to function properly, you can then use a vacuum sealer to remove any existing air. Moisture labels are also available to identify the item as moisture sensitive.

If you have any questions or you need a sample to review for your application please give our customer service a call at 1-800-537-0351 or email us at sales@all-spec.com. We enjoy receiving feedback and if you have any recommendations on what you would like to see on our blog, email us at marvlop@all-spec.com.

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