Page 125 - Engineering Plastics Handbook

Polyacetals 99

assembly is not just the in-plant joining of two halves of the valve; it
requires a complex, sophisticated automatic assembly cycle for which engi-
neering thermoplastics is ideally suited. Briefly, hot air at 350°C (662°F)
is aimed accurately onto a series of molded pins that precisely position the
valve components before final in-place assembly [20]. The pins are brought
to a plastic state; then cold-forming tools re-form and solidify the pins to
clamp the valve components together permanently, vibration-free and
tamper-proof [20].
Companies active in developing processes for polyacetals are listed in
Table 5.9.

References

1. Presumptive MACT for Acetal Resins Production,” draft, June 5, 1996, U.S.
Environmental Protection Agency (EPA).
2. The Columbia Electronic Encyclopedia, 6th ed., Columbia University Press, New
York, N.Y., USA, 2003.
3. “Occupational Exposure to Formaldehyde,” U.S. Occupational Safety and Health
Administration (OSHA) Fact Sheet 95-27, January 1, 1995.
4. Thomas Gruetzner and Hans Hasse, “Solubility of Formaldehyde and Trioxane in
Aqueous Solutions,” Institute of Technical Thermodynamics and Thermal Processing
Engineering, University of Stuttgart, Stuttgart, Germany.
5. Dr. James G. Speight, Chemical and Process Handbook, McGraw-Hill, New York,
N.Y., USA, 2002.
6. “Locating and Estimating Air Emissions from Sources of Formaldehyde (Revised),”
U.S. EPA, Office of Air and Radiation, Office of Air Quality Planning and Standards,
1991.
7. Christopher N. Bowman and Kathryn A. Berchtold, “(Meth)acrylic and (Meth)acry-
lamide Monomers Comprising Cyclic Acetal/Thioacetal Groups, Polymerizable
Compositions, and Polymers Obtained.” Department of Chemical Engineering,
University of Colorado, Boulder, Colorado, USA.
8. DuPont Company news items.
9. BASF news items.
10. Ticona news items.
11. K 2004, 16th Annual International Trade Show for Plastics & Rubber, Duesseldorf,
Germany, October 20–27, 2004 (organized by Messe Duesseldorf trade fair organizer
of 43 trade fairs and exhibitions).
12. “Acetal Polyoxymethylene Homopolymer—POM PTFE Lubricated,” azom.com Article
ID 875. Source: Plascams, Rubber and Plastics Research Association (RPRA).
13. “RTP Company Announces New PFPE Modifier Compounds Offering Improved Wear
Resistance,” Winona, Minn., USA, 2001.
14. “Acetal Polyoxymethylene Copolymer - POM 2% Silicone Lubricated,” azom.com
Article ID 876. Source: Plascams, Rubber and Plastics Research Association (RPRA).
15. “Acetal Extruded Stockshapes Have Color,” Quadrant Engineering Plastics Products,
Manufacturingtalk, a web publication, December 2004.
16. A. L. Hyde Company, Grenloch, N.J., USA.
17. Steffen Krug, “New Developments in MIM Sintering and Debinding Furnaces,” GERO-
Hochtemperaturoefen GmbH (high temperature furnace), Neuhausen, Germany,
2002.
18. National Metal and Materials Technology Center, Division of Materials Technology
School, Energy and Materials, King Mongkut’s University of Technology, Bangkok,
Thailand.
19. “Foam Concentrates for RTP Thermoplastic Compounds” RTP Company, Winona,
Minn., USA.