A midsole molding apparatus which enables production of a high-quality midsole is provided. The apparatus includes a through hole, which passes laterally through a midsole used for a shoe, to be integrally formed, preventing traces of forming the through hole from being left in the through hole and on the periphery of the through hole and a shaft mold crossing the inner space of upper and lower molds, forming extending portions such that the ends of the shaft mold extend beyond the boundary of the inner space, and seating the extending portions in press recesses of the upper and lower molds to seal the insides of the molds so as to prevent raw material from leaking from inside the molds when foaming and forming a midsole, to prevent parting lines and burrs from forming on the inner surface of the through hole passing laterally through the midsole.

The invention provides a porous stamp material for laser processing that is available for continuous extrusion molding. A material including at least 100 parts by weight of thermoplastic resin, 50-250 parts by weight of hydroxylated compound whose dehydration starting temperature is 100 to 500° C., and water-soluble pore-forming material that has 10-60 μm average particle diameter is mixed to obtain a mixed material. The obtained mixed material is extruded to obtain an extrusion molded product. The obtained extrusion molded product is processed with an aqueous solvent to elute the water-soluble pore-forming material, thereby yielding a porous stamp material that has continuous pores having 10-60 μm pore diameter. The obtained porous stamp material is laser-processed to manufacture a stamp.

A sole structure includes a sole component, which has an inner surface and an outer surface opposite the inner surface. The sole component has a length and a thickness. The sole component includes a sole material, and the sole material has a density. At least one of the thickness or the density varies along the length of the sole component. The sole component defines a plurality of holes extending from at least one of the inner surface and the outer surface and arranged to form an auxetic structure. The auxetic structure is configured such that, when the sole component is tensioned in a first direction, the sole component expands in both the first direction and in a second direction orthogonal to the first direction. A property of the auxetic structure varies as a function of the density or the thickness of the sole component.

Non-time dependent measured variables are used to effectively determine an optimal hold profile for an expanding crosslinking polymer part in a mold cavity. A system and/or approach may first inject molten expanding crosslinking polymer into a mold cavity, then measure at least one non-time dependent variable during an injection molding cycle. Next, the system and/or method commences a hold profile for the part, and upon completing the hold profile, the part is ejected from the mold cavity.

Methods of making a foamed article include: (a) milling a block or sheet of thermoplastic polymer to form a precursor; (b) crosslinking the thermoplastic polymer; (c) heating the precursor to a first temperature to soften the thermoplastic polymer; (d) infusing the thermoplastic polymer with at least one inert gas at a first pressure that is sufficient to cause the at least one inert gas to permeate into the softened thermoplastic polymer; and (e) while the thermoplastic polymer is softened, reducing the pressure to a second pressure below the first pressure to at least partially foam the precursor into a foamed article, wherein the foamed article is substantially the same shape as the precursor.

A method for producing a heat-shrinkable product is provided. First, a polymer composition containing a polymer, a crosslinking agent and a micro-encapsulated foaming agent uniformly dispensed therein is melt mixed. The foaming agent has a peak activation temperature which is higher than a temperature of the melt mixing. Next, the polymer composition is injection molded into a molded product. This carried out at the peak activation temperature to activate the foaming agent. Then, the molded product is crosslinked within the mold.

Non-time dependent measured variables are used to effectively determine an optimal hold profile for an expanding crosslinking polymer part in a mold cavity. A system and/or approach may first inject molten expanding crosslinking polymer into a mold cavity, then measure at least one non-time dependent variable during an injection molding cycle. Next, the system and/or method commences a hold profile for the part, and upon completing the hold profile, the part is ejected from the mold cavity.

Closed cell foam articles, such as sports balls, and related manufacturing methods are disclosed herein. The article includes a main body made of closed-cell elastomeric resin foam having a density ranging between about 0.050 sg and about 0.800 sg after curing. Some articles are assembled by inserting a cured core into a main body so that the core is secured in the main body via an interference fit, and the core has one or more portions extending to the exterior surface of the main body such that the an exposed surface of the one or more exposed portions of the core blend substantially with the exterior surface of the main body.

A method for producing a heat-shrinkable product is provided. First, a polymer composition containing a polymer, a crosslinking agent and a micro-encapsulated foaming agent uniformly dispensed therein is melt mixed. The foaming agent has a peak activation temperature which is higher than a temperature of the melt mixing. Next, the polymer composition is injection molded into a molded product. This carried out at the peak activation temperature to activate the foaming agent. Then, the molded product is crosslinked within the mold.

Non-time dependent measured variables are used to effectively determine an optimal hold profile for an expanding crosslinking polymer part in a mold cavity. A system and/or approach may first inject molten expanding crosslinking polymer into a mold cavity, then measure at least one non-time dependent variable during an injection molding cycle. Next, the system and/or method commences a hold profile for the part, and upon completing the hold profile, the part is ejected from the mold cavity, whereupon a cure profile is commenced.