Static shielding bag

• US 5,097,949 A
• Filed: 03/15/1991
• Issued: 03/24/1992
• Est. Priority Date: 03/15/1991
• Status: Expired due to Fees

• Current Assignee: Westvaco Corporation (Meadwestvaco Corporation)
• Original Assignee: Westvaco Corporation (Meadwestvaco Corporation)
• Inventors: Heldwein, Franz C.
• Primary Examiner(s): Foster, Jimmy G.
• Application Number:
  US07/669,895
• Time in Patent Office: 375 Days
• Field of Search: 206/328, 206/331, 206/332, 206/333, 206/524.2, 428/35.3
• US Class Current: 206/720
• CPC Class Codes: B32B 2250/24 All layers being polymeric
• CPC Class Codes: B32B 2307/31 Heat sealable
• CPC Class Codes: B32B 2323/04 Polyethylene
• CPC Class Codes: B32B 2323/10 Polypropylene
• CPC Class Codes: B32B 2367/00 Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/025 Electric or magnetic properties
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: H01L 21/67366 characterised by materials, roughness, coatings or the like materials relating to an injection moulding process B29C45/00; chemical composition of materials C08L51/00
• CPC Class Codes: H01L 21/67386 characterised by the construction of the closed carrier
• CPC Class Codes: H01L 21/67396 characterised by the presence of antistatic elements
• CPC Class Codes: H05K 13/0084 Containers and magazines for components, e.g. tube-like magazines
• CPC Class Codes: H05K 9/0067 Devices for protecting against damage from electrostatic discharge
• CPC Class Codes: Y10T 428/1338 Elemental metal containing

Abstract

A static shielding package is disclosed comprising an open end, a folded bottom and sealed side edges formed from a substantially rectangular transparent, flexible laminated segment of sheet material. The sheet material comprises an inner heat sealable carrier layer, an outer protective layer and a conductive layer sandwiched between said carrier layer and protective layer wherein said sheet material is folded over upon itself along a fold region to form the folded bottom of the package. The improvement comprises the addition of an auxiliary strip of static shielding material added to the package in the region of the folded bottom of the package to provide an alternative path for the conduction of electrical energy in the event of a disruption of the primary conductive layer of the package in the region of the fold area.

Claims

1. A generally rectangular shaped blank of packaging material (21) having side edges, opposed ends and a centrally located fold area, adapted to be formed into a package to receive and protect electronic components, said blank comprising in combination:

(a) a primary layer of laminated sheet material (22) having a first inner carrier layer (14) of electrically insulating material capable of being heat sealable to itself, a second outer protective layer (11) of a substantially transparent and printable material located exterior to said first carrier layer, and a first conductive layer (12) sandwiched between said first and second layers; and

,

(b) an auxiliary strip of laminated sheet material (23) comprising a second carrier layer (25) and at least one additional conductive layer (27) bonded to the carrier layer (14) of the laminated sheet material (22) in the region of the fold area (32) of the blank, said auxiliary strip (23) having substantially the same width as the primary layer (22) but lesser length to increase the thickness of the blank only in the region of the fold area and provide increased mechanical strength, so that the radius of any fold made in the fold area (32) will be great enough to reduce stresses that might cause a disruption of the conductive layer (12) when the blank is formed into a package (31).

2. The blank of claim 1 wherein the first inner carrier layer is a transparent, heat sealable polymeric material selected from the group consisting of polyethylene, polypropylene and coextrusions of polyethylene and polypropylene.

3. The blank of claim 2 wherein the first inner carrier layer has a thickness of from about 1 to 4 mils.

4. The blank of claim 3 wherein the second outer protection layer is a transparent printable material selected from the group consisting of polyesters, polyethylene and polypropylene.

5. The blank of claim 4 wherein the second outer protective layer has a thickness of from about 1 to 4 mils.

6. The blank of claim 5 wherein said first conductive layer comprises a metallic layer adhered to the inner surface of said outer protective layer.

7. The blank of claim 6 wherein said first conductive layer has a surface resistivity of less than about 10⁵ ohms per square.

8. The blank of claim 7 wherein said inner carrier layer has a surface resistivity of at least about 10⁸ ohms per square.

9. The blank of claim 8 wherein the first conductive layer is adhesively bonded to the outer surface of said inner carrier layer between said carrier layer and said outer protective layer.

10. The blank of claim 9 wherein the conductive layer of said auxiliary strip material is adhesively bonded to the inner surface of said first carrier layer between said first and second carrier layers.

11. An open end package formed from the blank of claim 10 wherein said side edges are heat sealed together after said blank element is folded over upon itself along the region of said fold area.

12. An open end package adapted to receive and protect electronic components, formed from a blank of substantially transparent, flexible sheet material said blank having side edges and a fold region, said blank comprising a primary layer of laminated sheet material having an inner carrier layer of a heat sealable polymeric material, an adhesive layer, a metal conductive layer and an outer protective layer, all bonded together, said blank being folded over upon itself along said fold region and said side edges being heat sealed together, the improvement comprising the addition of an auxiliary strip of laminated sheet material bonded to the inner surface of the carrier layer in the region of said fold area, said auxiliary strip of material comprising at least one additional conductive layer and a second carrier layer having substantially the same width as the primary layer of laminated material but lesser length so as to increase the thickness of the blank only in the region of the fold area to provide an alternative path for the conduction of electrical energy in the event of a disruption of the first conductive layer in said fold area.