Method of making paint brush with co-injection molded handle
AssigneeThe Wooster Brush Company
InventorRichard L. Barker
Life of this patent
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Abstract
A paint brush handle has an outer layer of a comfortable, relatively soft elastomeric material that surrounds a rigid core of foamed polyolefin. The handle is made using a co-injection process in which a mold cavity is first coated by an initial partial shot of the elastomeric material and then filled by injecting more elastomeric material and polyolefin material containing a foaming agent simultaneously. The simultaneous shot of these materials is achieved by injecting the materials through a single inlet passage into the mold cavity in which the flows are concentric, with the elastomeric material surrounding the polyolefin material. The ferrule is attached to the handle using nails or other suitable fasteners which penetrate into the rigid inner core.
Claims10
A method of making a paint brush handle in a mold having a cavity defining the shape of the paint brush handle with an axially extending grip portion and a head portion, the cavity having an inlet for molding material coaxially with the axis of the handle, comprising the steps of positioning a flow diverter in the head portion of the cavity opposite the inlet, directing through the inlet and toward the diverter an initial partial shot of an elastomeric material to form a coating on the inside of the mold cavity, and thereafter simultaneously injecting more elastomeric material and a polyolefin material containing a foaming agent surrounded by the elastomeric material to fill the balance of the mold cavity.
Dependencies are inferred from the claim text.