Intumescent electrical installation systems and processes for their production

• US 7,521,495 B2
• Filed: 12/21/2005
• Issued: 04/21/2009
• Est. Priority Date: 03/19/2002
• Status: Active Grant

• Current Assignee: Intumex GmbH
• Original Assignee: Intumex GmbH
• Inventors: Horacek, Heinrich, Pickhard, Walter
• Primary Examiner(s): SANDERS, KRIELLION ANTIONETTE
• Application Number:
  US11/312,372
• Publication Number:
  US 20060160926A1
• Time in Patent Office: 1,217 Days
• Field of Search: 524/100, 524/291, 524/299, 524/400, 524/404, 524/416, 524/447, 524/449, 524/451, 524/494, 524/495, 524/570, 524/571, 524/586, 524/587
• US Class Current: 524/100
• CPC Class Codes: H02G 3/0412 Heat or fire protective means for fire in electric circuits A62C3/16

Abstract

Intumescent, electrical installation systems which comprise an injection molding material of polyolefins or polyimides in combination with intumescent additives, the melting points of the polyolefins and of the polyimides being lower than the intumescence temperature of the intumescent additives.

Claims

1. An injection molded intumescent, electrical installation system, which is formed from an injection molding material consisting of a) 20-50% per weight of a polyimide formed from a bismaleimide or aromatic diamine b) 50-80% per weight of vermicular graphite as intumescent additive, c) 0-20% per weight of inorganic fillers and d) 0-5% per weight of dispersants

2. The injection molded intumescent, electrical installation system as claimed in claim 1, wherein the polyimide is formed from a low-melting bismaleimide and is highly crosslinked by addition reaction under the action of heat.

3. The injection molded intumescent electrical installation system as claimed in claim 1, wherein the injection molding material contains inorganic fillers from the group consisting of kaolin, clays, mica, wollastonite, calcium silicates, titanium dioxide, zinc borate, quartz, zinc oxide, apatite, talc, aluminum phosphates, ATH, Mg(OH)₂, chalk, glass fibers or mineral fibers.

4. The injection molded intumescent, electrical installation system as claimed in claim 3, wherein clays or micas which are present as nanoparticles in the mixture of polymer, intumescent additive and filler are used as the inorganic filler.

5. The injection molded intumescent, electrical installation system as claimed in claim 1, wherein the injection molding material contains dispersants from the group consisting of zinc stearate or calcium stearate, glyceryl stearate, pentaerythrityl tetrastearate, cetyl palmitate, ethylenedistearoyldiamide C₁₄-C₁₈ fatty alcohols, dicarboxylic esters, fatty amines or paraffins.

6. The injection molded intumescent, electrical installation system as claimed in claim 1, wherein the material thickness is such that it corresponds to the volume of the installation system divided by the product of twice the lateral surface area and the maximum expansion factor, so that the installation system is completely filled with foam by intumescence and a compression factor of 2 is present.

7. The injection molded intumescent, electrical installation system as claimed in claim 1 which is a socket or box.

8. The injection molded intumescent, electrical installation system as claimed in claim 7 which is a conduit box, switch box or junction box.

9. The injection molded intumescent, electrical installation system of claim 7 which is a wall socket.

10. The injection molded intumescent, electrical installation system of claim 7 which is in the form of conduits, angle boxes, branch-Ts, cross boxes, a combination conduit box/switch box, a double conduit box/switch box, a semiflush-mounted conduit box, or a ceiling light connection box, a wall light connection box, a dome box, a double equipment or switch box, a triple equipment box, an equipment conduit box, a junction box/switch box, a transition box, or a universal box.

11. The injection molded intumescent electrical installation system according to claim 1 wherein the bismaleimide is diphenylmethane 4,4-bismaleimide.

12. The injection molded intumescent electrical installation system according to claim 2 wherein the bismaleimide has a melting point below about 2000°

C.

13. An injection molded intumescent system which is produced by injection molding a powder mixture comprising bismaleimide and vermicular graphite under the action of heat to form a highly crosslinked polyimide.