US 6,319,964 B1Granted

Acoustic baffle with predetermined directional expansion characteristics

AssigneeSika Corporation

InventorsNorman E. Blank, Cheong Kow

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Abstract

Heat-expandable molded synthetic resin seal and baffle components adapted for use in automobile body cavities or the like are provided which are designed to preferentially expand upon heating in desired directions and to a desired degree, in order to properly seal irregular or special cavity shapes. The molded components of the invention have selected body surface portions thereof UV crosslinked to a depth of up to about 0.5 mm, while other portions of the molded body are not crosslinked; upon heating, the crosslinked portions expand at a slower rate and to a lesser extent than non-crosslinked body portions. The preferred synthetic resin includes a grafted anhydride polymer, a terminal epoxide polymer additive, a blowing agent, a UV photoinitiator and a UV crosslinkable resin system.

Claims41

Dependent claims

A method of preparing a heat-expandable component, said method comprising the steps of:

forming a body presenting an outer surface, said body comprising a synthetic resin matrix including a quantity of a grafted anhydride polymer, an amount of a polymer additive containing a terminal epoxide group which reacts with at least a part of the anhydride polymer when the component is heated to effect expansion thereof, and a sufficient quantity of a blowing agent capable of expanding the component upon heating thereof, at least a portion of said body surface including a UV photoinitiator and a crosslinkable synthetic resin;
and
subjecting some of said body portion to UV radiation to crosslink said matrix to a depth of up to about 0.5 mm so that, when the component is sufficiently heated to effect expansion thereof, said UV crosslinked portion expands at a lower rate and to a lesser extent than other portions of said body.

Dependencies are inferred from the claim text.