 Polyurethane-epoxy casting resin |
| The epoxy resin components useful for the purposes of this invention are those epoxy compounds ... |
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| Water based coating composition and polymer film coated therewith |
| What is claimed is: 1. A water based antistatic polymer film coating composition comprising: (a) at ... |
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| Oligomeric aromatic dispersing agents, method of making same, and dispersions made therefrom |
| OF THE PREFERRED EMBODIMENTS As stated above, the oligomeric aromatic dispersant is a reaction ... |
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| Softening non-swelling polyurethane |
| While this invention is satisfied by embodiments in many different forms, there will herein be ... |
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| Coating composition of an acrylic polymer, polyol and polyisocyanate crosslinking agent |
| We claim: 1. A clear coating composition which cures at ambient temperatures having a film forming ... |
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| Coating composition of hydroxy functional acrylic polymer, polyol and polyisocyanate crosslinking agent |
| We claim: 1. A clear coating composition having a film forming binder solids content of about 30-70%... |
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| Polypropylene resin composition |
| What is claimed is: 1. A polypropylene resin composition consisting essentially of 50 to 90% by ... |
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| Coating composition having low volatile organic content |
| OF THE INVENTION The coating composition includes, in an organic phase, a polymer, preferably an ... |
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| Molded product of a polypropylene resin |
| Under these circumstances, it is an object of this invention to provide a molded product of a ... |
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Molded soft elastomer/hard polyester composition with noise damping properties
| Details |
Inventors: Poppe, Ernst; Huber, Hans-Jurgen; Hoffmann, Ralf; Polese, Angelo;
Assignee: E. I. du Pont de Nemours and Company (Wilmington, DE)
Primary Examiner: Cain; Edward J.
Assistant Examiner:
Attorney, Agent or Firm:
The invention provides a molded composition having improved noise damping properties, made of a blend of a soft thermoplastic polyether elastomer and a hard polyester resin reinforced with a fibrous or particulate filler, the molded composition having an inhomogeneous structure comprising a surface part which is rich in elastomer and depleted in the polyester resin and the reinforcing filler compared to its inner part, obtained by monocomponent injection molding of a blend of the soft and the hard polyester resin wherein only the polyester resin contains the reinforcing particulate filler. The molded composition has a flex modulus Fm in the range 0.5 to 10 GPa, and maintains a sufficient minimum tan delta damping factor t_ over a temperature range of -50.degree. C. to 170.degree. C. |
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DETAILED DESCRIPTION OF THE INVENTION The inhomogeneous structure of the molded composition according to the invention contains domains/layers of different density, modulus and reinforcing filler concentration.
One domain is comprised primarily of a soft elastomer and the other domain is comprised of reinforced hard polyester resin containing soft elastomer.
Though the structure is inhomogeneous, there is good bonding between the soft elastomer and the hard polyester resin as they were melted together, despite the fact that they have different melting points and viscosities.
Inspection of the molded structure reveals a more-or-less uniform concentration of the reinforcing fibers in the middle inner region of the molded structure which is relatively enriched in the hard polyester, and a surface layer enriched with the elastomer which has segregated from the reinforced polyester/fibers.
This is contrary to conventional standard molding practices where it is usually sought to obtain a homogeneous final structure.
In molding the composition of the invention, the soft elastomer and the hard polyester resin in the initial substantially homogeneous blend have a mismatch of melting point, viscosity and modulus so as to make possible the inhomogeneous structure, but the two polymers maintain sufficient compatibility to bond well together after melting.
Prior to molding, the reinforcing fibers are present only in one of the starting resins, namely in the hard polyester which has a higher melting point than the elastomer.
During the molding step, the elastomer melts and begins to segregate towards the surface due to its lower melting point and to its lower viscosity at the molding temperature.
At the same time, the reinforced polyester remains more solid and stays with the reinforcing fibers.
In the inner region of the molded body, the soft elastomer is enclosed in the reinforced polyester resin, hence improving its thermic stability.
The reinforced middle inner region of the molded structure which is relatively enriched in the hard polyester also confers on the molded body an adequate rigidity
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Adhesives and Rubbers 
