| 3M Company | A&E Plastics |
| Aaron Equipment | ABC Colorants |
| Abell-Howe Company | Action Technology |
| Advance Color | Advanced Drainage Systems |
| Advanced Electric | Aim Packaging |
| Album Extrusions | Allied Resinous Products |
| Amanco | American Cable Company |
| American Cyanamid | American Motors Company |
| American Sheet | American Thermoplastics |
| Amoco Fibers | Ampacet Corporation |
| Applied Plastics | Applied Products |
| AT&T Company | ATC Company |
| ATE Inc. | B&L Bauliauis Holland |
| B&M Plastics | B.P. Polymers |
| Balco Plastics | BASF Germany |
| Bee Polymer | Bethlehem Steel |
| Blachford Corporation | Blacko Inc. |
| Boyle Midway | Bredero Price Co. |
| British Petroleum Industries | C.R.C. Evans |
| Cadillac Plastics | Canaco Plastics |
| Canterbury Engineering Company Inc. | Carlon Company |
| Cascade Plastics | Cassa Industries |
| Celanese International | Central Nebraska / ITS |
| Champion Blower Company | Champion Infiltrator |
| Chemical Resins Company | Chemplex Industries |
| Clear Pack Company | CNC (China National Chemical) |
| Coleco Company | Collins & Aikinan |
| Colonial Rubber | Commercial Vinyls Inc. |
| Compounding Technology Inc. | Concord Industries |
| Conrad Company | Consumer Plastics |
| Container Corporation | Continental Can Company |
| Co-Poly-Ex | Creative Packaging Company |
| Crest Mfg. | Cross Color |
| Crowe Rope Company | CTI Inc. |
| Custom Tapes Inc. | Daelim Company |
| Dande Plastics | Detroit Forming Inc. |
| DOT Plastics | DOW Chemical |
| DSM Engineering Plastics | DuPont Company |
| East Jordan Plastics | Eastern Balance |
| Easton Chemical Company | EKCO/PCA Products |
| Entek Products | Ex-Tech |
| Fabri-Kal Corporation | Federal Sign and Signal Company |
| Ferro Corporation | Flex-o-glass Inc. |
| Ford Motor | Formed Products |
| General Foam | General Motors Company |
| Great Lakes Chemical Co. | Graber Industries |
| Gulf Plastics | Hendrickson |
| Hercules | Hills McCanna/Prescon |
| Inline Plastics | Inplex Inc. |
| J.P. Stevens Company | Jarrow Products Inc. |
| Joliet Equipment Corp. | K&M Plastics Inc. |
| K.W. Plastics | Kar-Rite International |
| KE Plastics, Recycling Division | Keyes Fibre |
| Kimberly-Clark | KM Plastics |
| K-S-H Canada Inc. | Lab-Line Instruments Inc. |
| Lambda Markt. | Louisiana-Pacific |
| Lucky Goldstar Korea | Lustro Plastics Company |
| Matsui Company | Maynard Plastics |
| McCreary Industries | Mercer Plastics |
| Midwest Recycling | Mitsubishi Heavy Industries |
| Monsanto Company | MRC Polymers Inc. |
| National Seal Company | NCI Inc. |
| Newman-Green Inc. | Nike |
| Norris Industries | Northern Pipe Products |
| Northern Plastics Company | Nova Chemical Company |
| Objective Industries Inc. | Owens - Illinois Inc. |
| P&M Industries | Pace Industries |
| Pantasote | PC Plastics Inc. |
| PCA | Peacock Colors Inc. |
| Pemex Company (Mexico) | Performance Packaging Inc. |
| Phillips Petroleum | Plasticolors Inc. |
| Plasticos Espumados | Plastiques Cascades |
| Plastofile Industries Inc. | Plexco Inc. |
| Plicofiex Corp. | Ponca Pellets |
| Poly Pipe Industries Inc. | PPC Industries Inc. |
| Portage Industries Corp. | Prescon Corp. |
| PPG Industries Inc. | Quality Films Inc. |
| Primex Plastics | R. Plastics Company |
| Quick Plastics | Republic Packaging Corp. |
| Reed Plastics Inc. | Research/Dexter |
| Research Polymers | Reynolds Metals Company |
| Rexene Company | Rockwell International Corp. |
| Rock Ten Company | S&H Pipe |
| Ryan Development Company | Sanderson Plumbing |
| San Juan Plastics | Shannon Industries |
| Schulman, A. Inc. | Signal Division of American Amerace |
| Shell | Silite Company |
| Signode Corp. | Spacemakes Company |
| So. Polymers Inc. | Storm Products |
| Stevens, J.P. & Company Inc. | Swift Adhesives |
| Swedlow Corporation | Tenneco PCA Division |
| Tecknor Apex Inc. | Tetra Plastics/Now Nike Uretha |
| Tetra Plastics Inc. | Textrude Company |
| Texi Colors Inc. | Travelnol Inc. |
| Thermofil Inc. | U.C. Industries |
| Trirutex Company Inc. | Uniroyal Company |
| Union Carbide Corp. | Upjohn Company |
| United States Gypsum Company | Vacu-Maid Company |
| USS Chemicals | Vinyl Plastics Inc. |
| Videx Company | Wilson Fiberfil Inc. |
| Wilkinson Company | |
| Xaloy Inc. |