Low-density molding compound

Patent metadata

Field	Value
Publication number	US-9663608-B2
Application number	US-201414289093-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 13, 2005
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A molding composition formulation includes a thermoset cross-linkable 12 to 45 micron polymeric resin. Hollow glass microspheroids are present from 2 to 12 total weight percent. An article formed from such a composition is further strengthened by the addition of a surface activating agent bonded to the surface of the glass microspheroids. Conventional particulate fillers when added to an inventive formulation provide enhanced performance when the filler particle has a size sufficiently small to insert within adjacent microspheroid interstitial voids. An unsaturated polyester resin so formed is particularly well suited for the formation of sheet molding compound formulations.

First claim

The invention claimed is:

1. A molding composition formulation comprising:
a thermoset cross-linkable polymeric resin; and
hollow glass microspheroids present from 2 to 12 total weight percent of the formulation; and
a surface activating agent that bonds to one of said hollow glass microspheroids, said surface activating agent is an alkoxysilane reactive with a silica surface of said one of said hollow glass microspheroids;
a free radical catalyst for curing said resin;
wherein said surface activating agent is present in concentrations of about 0.05 to 0.5 grams of said surface activating agent Per gram of hollow glass microspheroids, and said hollow glass microspheroids have an aspect ratio of between 1 and 1.6.

2. The formulation of claim 1 further comprising a low profile additive.

3. The formulation of claim 1 further comprising a fiber filler.

4. The formulation of claim 1 wherein said alkoxysilane is one of: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl) bis(trimethylsiloxy)methylsilane, (3-glycidoxypropyl)methyldiethoxysilane, (3-glycidoxypropyl) dimethylethoxysilane, (3-glycidoxypropyl)methyldimethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxypropyldimethylethoxysilane, methacryloxypropyldimethylmethoxysilane, ethacryloxypropylmethyldimethoxysilane, methacryloxypropyltriethoxysilane, methoxymethyltrimethylsilane, 3-methoxypropyltrimethoxysilane, 3-methacryloxypropyldimethylchlorosilane, methacryloxypropylmethyldichlorosilane, methacryloxypropyltrichlorosilane, 3-isocyanatopropyldimethylchlorosilane, 3-isocyanatopropyltriethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, or combinations thereof.

5. The formulation of claim 1 wherein said surface activating agent comprises an ethenically unsaturated moiety that is reactive under free radical cross-linking conditions so as to covalently bond said hollow glass microsphere to a surrounding matrix of said resin.

6. The formulation of claim 1 further comprising a particulate filler.

7. The formulation of claim 1 wherein said resin is a polyester.

8. The formulation of claim 1 wherein said resin is an epoxy or a polyurethane.

9. The formulation of claim 4 wherein said particulate filler is calcium carbonate.

Assignees

• Continental Structural Plastics Inc

Inventors

• Beach Brian A
• Guha Probir K
• Haskell Brad
• Siwajek Michael J

Classifications

• Y10T428/2995

  Silane, siloxane or silicone coating · CPC title

• Y10T428/2996

  Glass particles or spheres · CPC title

• C08K2003/265

  Calcium, strontium or barium carbonate · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title

• C08G18/837 Primary

  by silicon containing compounds · CPC title