This article covers how to read the specifications of the aluminum foil bag itself. To buy: for anti-static and general styles and the size lookup, see Anti-Static Aluminum Foil Bags; for shielding bags in packs of 100, see ESD Shielding Bags. Not sure which bag to choose? See How to choose ESD bags; for moisture protection of complete PCBA boards, see PCBA moisture barrier packaging.
An anti-static aluminum foil bag (also called an ESD aluminum foil bag; in English, moisture barrier bag, MBB for short) is a three-layer laminated bag with an outer polyester layer, a middle aluminum foil layer, and an inner anti-static PE layer, used to block water vapor and protect static-sensitive electronic parts. “Anti-static bag,” “ESD bag,” and “static bag” are common catch-all names; pink PE bags are also called by these names, and the two are different.
Key points first
Structure: three layers, dissipative polyester (or polymer) / aluminum foil / dissipative PE; the three public data sheets agree.
Look at three figures in the specification: water vapor transmission rate (moisture protection), shielding energy (nJ, shielding), and surface resistance (anti-static). Each has a standard measurement method; the figures and conditions in each maker’s data sheet differ and cannot be compared directly.
Sealing: heat sealing, optionally after drawing a vacuum; for heat-seal temperature ranges, see Section 4.
The marked values of the aluminum foil bags on this site (including layer structure, thickness, and surface resistance) come with no test report; the figures in this article are all as written in public data sheets or standards, for learning to read specifications, not the specifications of Jiahon’s goods.
1. Structure: what each of the three layers does
| Layer | Common material | Function |
|---|---|---|
| Outer layer | Dissipative polyester (PET) | The outer surface of the bag; bag styles on this site can be printed in one color |
| Middle layer | Aluminum foil | The water vapor barrier layer; the water vapor transmission rate in the data sheet is the result measured on this layered structure; conductive layers such as aluminum are the source of shielding against external electrostatic fields (yclas) |
| Inner layer | Dissipative PE | The sealing surface (heat sealing in Section 4); packaging in direct contact with components should be static-dissipative (Desco Q&A page, citing S541) |
Sources: three-layer structure from the three data sheets of Bondline, Desco, and SCC; yclas (anti-static bags vs. static shielding bags); Desco Q&A page.
Thickness of each layer: all three data sheets give only the total thickness, not the thickness of each layer (Bondline 4 mil ±10%, Desco and SCC 4.0 mil; 1 mil = 0.0254 mm, so about 0.10 mm). The total thickness of the 9312 styles on this site is 0.10–0.16 mm (marked values; see the size lookup table). Since the layer thicknesses cannot be found, this article does not give them; the data sheets also have no data on capabilities of each layer such as tear resistance or light blocking, so this article does not give those either.
The US military specification MIL-PRF-81705E classifies this kind of material as Barrier Materials, Flexible, Electrostatic Protective, Heat-Sealable, of which Type I provides both water vapor barrier and electromagnetic interference attenuation. Source: EverySpec
2. Moisture protection: how to read the water vapor transmission rate
The water vapor transmission rate (WVTR; some data sheets write MVTR) is the amount of water vapor passing through a unit area per unit time; the common unit in data sheets is g/100 in²·24 h, and the smaller the figure, the less water vapor gets into the bag. How the three public data sheets put it:
| Data sheet | Water vapor transmission rate | Test method | Total thickness |
|---|---|---|---|
| Bondline (2023) | ≤0.002 g/100 in²·24 h (= 0.0310 g/m², 40°C) | ASTM F392 (after flexing) | 4 mil ±10% |
| Desco | ≤0.0003 g/100 in²·24 h | ASTM F1249; F392 flex test also listed | 4.0 mil |
| SCC Dri-Shield 3400 | <0.0003 g/100 in²·24 h | ASTM F1249 | 4.0 mil |
Sources: data sheets of Bondline, Desco, and SCC. These are figures for other makers’ products, not the specifications of Jiahon’s goods.
Bondline and Desco list a flex test (ASTM F392), and SCC does not; only Bondline states 40°C. The conditions differ, so the three figures cannot be ranked directly. The aluminum foil bags on this site have no water vapor transmission rate report; if you need a value, please inquire.
Moisture protection depends on the whole method: Section 1.1 of IPC/JEDEC J-STD-033D states that the dry-packing procedure specified by the standard provides a shelf life of at least 12 months from the bag seal date; the standard covers moisture barrier bags (MBB), desiccant, and humidity indicator cards. Source: ANSI preview page. For desiccant, see Electronic packaging desiccant; for indicator cards, see Blue six-spot humidity indicator card; for the levels and baking conditions of moisture-sensitive devices, see What is MSL for moisture-sensitive devices.
3. Anti-static: surface resistance and shielding energy
Surface resistance: ANSI/ESD S541 defines static-dissipative material as ≥1.0×10⁴ Ω and <1.0×10¹¹ Ω; packaging in direct contact with components should fall within this range. Source: Desco Q&A page. The test method is ANSI/ESD STM11.11 (the SCC data sheet says ASTM D257 or STM11.11). For the steps of measuring it yourself and common mistakes, see How to measure anti-static values so they count.
Shielding energy: ANSI/ESD STM11.31 measures the discharge energy that penetrates the bag wall, in nanojoules (nJ). The shielding threshold in S541 is 50 nJ or less. The three data sheets each state: Bondline <50 nJ, SCC <20 nJ, Desco <10 nJ. Source: Desco Q&A page; ESDA S541-2026 table of contents (only shows that a 6.3 shielding section exists).
To see what a report looks like, here is a public example: Antistat’s shielding bag test report, with 100 bags submitted and a results table listing measurements on 6 samples; average inner and outer surface resistance 3.75×10⁹ and 8.69×10⁹ Ω, and shielding energy 14.4 nJ (relative humidity 50%). Source: Antistat static shielding bag test report (ANT010SSB). This is a report on a single product, shown only to demonstrate how to read one.
4. Sealing: heat sealing and vacuum
| Data sheet | Heat-seal temperature | Time / pressure |
|---|---|---|
| Bondline | 150–200°C | — |
| Desco | 140–204°C | 0.6–4.5 seconds |
| SCC | 300–400°F (about 149–204°C) | 0.6–4.5 seconds, 30–70 PSI |
Sources: data sheets of Bondline, Desco, and SCC; the °F conversion is this article’s own calculation.
The ranges are similar but not the same; adjust the actual conditions to the bag material and the sealer, and do a small trial seal before mass production. The aluminum foil bags on this site come with no sealing conditions; if you need them, please inquire. Vacuum packing means drawing out the air first and then heat sealing; an electronics design magazine lists heat sealing after evacuation as the final step of moisture protection. Source: Electronic Design
Bag types on this site (zip-lock, gusset, reel, and tray bags are mostly anti-static styles): flat bags (three-side seal), zip-lock bags (also called ziplock or zipper bags, with a zipper track that can be opened and closed repeatedly), gusset bags, reel bags, and tray bags; for sizes, see the size lookup table. One-color printing is available (lot number, warning text, logo). The dry-packing chapter of J-STD-033D includes a “Labels” section and examples of caution labels; the warning text and logo on the bags on this site are specified by you, so please inquire about print content. The anti-static styles include zip-lock bags of 23 × 26 cm for 7-inch reels and 40 × 44 cm for 13-inch reels (marked values; see the size lookup table on the Anti-Static Aluminum Foil Bags page).
Sources: table of contents of the IPC/JEDEC J-STD-033D preview page (3.3.3 Labels, Figures 3-4A / 3-4B caution label examples); sizes are marked values from Jiahon’s 9312 size lookup table.
5. Standards at a glance
| Standard | What it covers |
|---|---|
| MIL-PRF-81705E | Flexible, electrostatic protective, heat-sealable barrier materials (Type I: water vapor barrier and electromagnetic interference attenuation). EverySpec |
| IPC/JEDEC J-STD-033 | Handling, packing, and dry-packing procedures for moisture-sensitive devices. ANSI preview page |
| ANSI/ESD S541 | Packaging materials for static-sensitive items: resistance classification, shielding threshold. Desco Q&A page; ESDA table of contents |
| ANSI/ESD STM11.11 | Surface resistance measurement. SCC data sheet |
| ANSI/ESD STM11.31 | Discharge penetration energy of shielding bags. Desco Q&A page |
| ASTM F1249, F392 | Water vapor transmission rate test methods; F392 is testing after flexing. Desco; Bondline |
FAQ
What are the three layers of an anti-static aluminum foil bag, and what does each do?
The outer layer is dissipative polyester (PET), the middle layer is aluminum foil, and the inner layer is dissipative PE. All three public data sheets list these three layers, but give only the total thickness, not the thickness of each layer; the middle aluminum foil layer is the source of the water vapor barrier and the shielding, and the inner layer is the static-dissipative surface in contact with components.
Sources: Bondline, Desco, SCC.
What is the water vapor transmission rate of a moisture barrier aluminum foil bag?
There is no single general figure; it depends on the data sheet and the test conditions. The three public data sheets: Bondline ≤0.002, Desco ≤0.0003, SCC <0.0003 g/100 in²·24 h; methods and conditions differ, so they cannot be compared with each other, and they are not figures for Jiahon’s goods.
Sources: Bondline, Desco, SCC.
What should the heat-seal temperature of an aluminum foil bag be set to?
The range in the public data sheets is 140–204°C (Bondline 150–200°C, Desco 140–204°C, SCC about 149–204°C), with a time of 0.6–4.5 seconds. Adjust to the bag material and the sealer in practice, and do a small trial seal before mass production.
Sources: Bondline, Desco, SCC.
Why pair it with desiccant and a humidity indicator card?
The dry-packing procedure of J-STD-033 consists of a moisture barrier bag, desiccant, and a humidity indicator card: the desiccant absorbs the water vapor remaining in the bag, and the indicator card lets you judge on opening the bag whether it took on moisture during packing.
Sources: IPC/JEDEC J-STD-033D preview page (the section headings list MBB, desiccant, and humidity indicator card); Electronic Design (the uses of desiccant and indicator cards).
How long can dry packing keep?
Section 1.1 of J-STD-033D states that the dry-packing procedure specified by the standard provides a shelf life of at least 12 months from the bag seal date. This is the result of packing by the standard procedure and cannot be taken directly as the specification of any particular bag.
Source: IPC/JEDEC J-STD-033D preview page, §1.1.
How is surface resistance classified?
The static-dissipative range in ANSI/ESD S541 is ≥1.0×10⁴ Ω and <1.0×10¹¹ Ω. Packaging in direct contact with components should be dissipative.
Sources: Desco Q&A page, S541 7.2.2; ESDA S541-2026 table of contents (only shows that a 6.2 resistance classification section exists).
How does an anti-static aluminum foil bag differ from an ordinary aluminum foil bag?
The difference is whether the inner layer has a static-dissipative treatment. The surface resistance, triboelectric voltage, puncture resistance, and seal strength marked for the anti-static styles on this site are listed in the comparison table on the Anti-Static Aluminum Foil Bags page; the general styles have no anti-static treatment and are used for packaging that only needs moisture and light protection, such as food, tea, coffee beans, and chemicals. These are marked values with no test report attached.
Further reading: How to choose ESD bags, PCBA moisture barrier packaging, What is MSL for moisture-sensitive devices, How to measure anti-static values so they count.