Pulp-molded paper lid for beverage cup and method for fabricating the same

A pulp-molded paper lid for a beverage cup, which is made by two upper and lower mold assemblies used for a thermo-compression forming in a wet-fiber pulp-molded process, wherein, the pulp-molded paper lid comprises:

• a topside ring, formed along an outer peripheral edge of the pulp-molded paper lid and having an outermost sidewall located on a side of the topside ring and downwardly extended, the topside ring configured for accommodating an insertion of a convex-ridge ring around an opening of a body of the corresponding cup;
• a central dominating portion, upwardly extended from the pulp-molded paper lid to form an annular sidewall thereon around a central short axis of the pulp-molded paper lid, and to form a beverage outlet thereon;
• and characterized in that, the pulp-molded paper lid further comprises:
• a generating-elasticity device, located on between the annular sidewall of the central dominating portion and the topside ring, wherein along radial directions of the pulp-molded paper lid, the generating-elasticity device is respectively integrally formed with a movable bearing wall, a movable linkage wall and at least one bended end interconnecting between the movable bearing wall and the movable linkage wall, the movable bearing wall is permanently connected to the other opposed side of the topside ring, the movable linkage wall is permanently connected to the annular sidewall, a first transversely cross-sectional width is defined among the movable bearing wall, the movable linkage wall and the at least one bended end and is extended along the radial directions of the pulp-molded paper lid, while the topside ring of the pulp-molded paper lid accommodates the convex-ridge ring of the corresponding cup body therein by bearing an external pressure thereon, the first transversely cross-sectional width of the generating-elasticity device is acted as pre-compressed, with a compressive deformation occurring therein along the radial directions of the pulp-molded paper lid, to become a second transversely cross-sectional width, and by removal of the external pressure, the generating-elasticity device is released from the pre-compression to exert preloaded elastic forces through the movable bearing wall, toward the convex-ridge ring of the corresponding cup body, along the radial directions of the pulp-molded paper lid, and the second transversely cross-sectional width becomes a third transversely cross-sectional width, the preloaded elastic forces are used to clamp-retain the convex-ridge ring of the corresponding cup body within between the movable bearing wall and the outermost sidewall, wherein the third transversely cross-sectional width is smaller than each of the first transversely cross-sectional width and the second transversely cross-sectional width.

A method for fabricating a pulp-molded paper lid for a beverage cup, performed by a wet-fiber pulp-molded process, which comprises:

• a suctioning-slurry and pre-compression step, comprising:
• collecting a slurry and pre-compressing the collected slurry into a wet pulp body;
• a thermo-compression forming step, comprising:
• performing at least one-time thermo-compression formation of the wet pulp body by mutually matching two upper and lower mold assemblies, to form a product of the pulp-molded paper lid, wherein the product of the pulp-molded paper lid comprises:
• a topside ring, formed along an outer peripheral edge of the product of the pulp-molded paper lid and having an outermost sidewall located on a side of the topside ring and downwardly extended, the topside ring is configured for accommodating an insertion of a convex-ridge ring around an opening of a body of the corresponding cup;
• a central dominating portion, upwardly extended from the product of the pulp-molded paper lid and formed with a beverage outlet;
• and a generating-elasticity device, interconnected between the central dominating portion and the topside ring between, along radial directions of the product of the pulp-molded paper lid;
• and
• a one-time demold step, comprising:
• forming the product of the pulp-molded paper lid, only along demold directions parallel to the central longitudinal axis of the upper and lower mold assemblies, by the generating-elasticity device and the topside ring both which have demolded surfaces formed at positive draft angles relative to a central longitudinal axis of the upper and lower mold assemblies, for performing a one-time demold.