Foamed polymeric shrink-fit objects and their process of manufacture
AssigneeKabel-und Metallwerke Gutehoffnungshutte Aktiengesellschaft
InventorsHermann U. Voigt, Eckard Schleese
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Abstract
A shrink-fit article is made by extruding a silane-grafted polymer which foams, at least at its surface, and cross-links. Upon completion of foaming and cross-linking, the article is expanded while (still) warm and cooled in the expanded state.
Claims18
A shrink-fitting article such as a shrink hose, shrink sleeve, or shrink cap, made from a hollow article comprised of an extruded and cross-linked foam material, the hollow article as a whole having been expanded to a larger size following completion of cross-linking and foam expansion.
A method of making a shrink-fit article such as a hose, a sleeve, a cap, or the like, comprising the steps of
- extruding or injection-molding a silane-grafted polymeric material capable of cross-linking in the presence of moisture, under development of foaming, at least at the surface, in order to shape-form a hollow polymeric article in the configuration it is to have following a shrink fit;
- causing the article as extruded to cross-link in the presence of moisture;
- expanding the cross-linked and foamed article at an elevated temperature to obtain larger dimensions;
- and
- cooling the article in the expanded state to form said shrink-fit article.
The method of making a shrinks-fit object, comprising the steps of
- providing a polymer blend with silane as a graft component;
- causing the graft component to be grafted upon the polymer, the graft component being of the type for cross-linking the polymer molecules in the presence of moisture;
- shaping the grafted-on polymer into a particular hollow object and causing at least a portion of the blend to foam by means of blowing in order to obtain at least partially a foamed surface;
- exposing said grafted-on polymer to moisture for obtaining the cross-linking;
- expanding the completely shaped and completely cross-linked object as a whole at an elevated temperature;
- and
- maintaining the expanded state as the object cools to obtain said shrink-fit object.
The method of making a shrink-fit article such as a hose, a sleeve, a cap, or the like, comprising the steps of
- providing a blend of a silane and a base polymer and a blowing agent;
- extruding the blend to melt the blend and to graft the silane onto the base polymer,
- and to obtain foaming while forming the article;
- causing the article to cross-link by exposure to moisture;
- re-shaping the article prior to completion of cross-linking to form a hollow article;
- expanding the hollow article as a whole and at an elevated temperature;
- and
- cooling the article in the expanded state to form a shrink-fit article.
Dependencies are inferred from the claim text.