The method for manufacturing a foamed product uses a manufacturing apparatus having a plasticizing cylinder in which an introduction port for introducing a physical blowing agent into a starvation zone is formed, and an introduction speed adjustment container connected to the introduction port, wherein the manufacturing method comprises: turning a thermoplastic resin into a molten resin; introducing the physical blowing agent at a predetermined pressure into the starvation zone through the introduction speed adjustment container and maintaining the starvation zone at a predetermined pressure; setting the molten resin to a starved state; bringing the molten resin in the starved state and the pressurized fluid into contact with each other; and molding the molten resin into a foamed product. The maximum value of the inner diameter of the introduction speed adjustment container is larger than the inner diameter of the introduction port.

A method of forming a plurality of fasteners includes extruding a continuous strip of material, the continuous strip defining a base portion, a tip portion, and a stem portion extending between the base portion and the tip portion. A portion of material is removed from the continuous strip of material along the tip portion such that a plurality of tip portions are separated from each other and spaced apart, each tip portion having at least one flexible tab. The continuous strip of material is then extruded through a foaming die, wherein the flexible tabs are elastically displaced away from the base portion during a foaming process such that a foam material fills a cavity of the foaming die to form a sealing element around the stem portion. Portions of the continuous strip between each of the tip portions are separated to produce a plurality of individual sealed fasteners.

In one embodiment, a method of forming an extruded board includes mixing a resin and a foaming agent, melting the mixed resin and foaming agent to form a uniformly colored extrudate, differentially expanding voids formed from the foaming agent within the uniformly colored extrudate by passing the uniformly colored extrudate through a breaker plate, forming a board with the differentially expanded voids and uniformly colored extrudate, and forming lightened portions on an outermost surface of the formed board.

A resin foam production apparatus is provided including: a metal mold including a foaming part and a discharge part; and an extruder configured to feed a resin foamable composition into the metal mold to cause the resin foamable composition to pass through the discharge part. The resin foamable composition comprises at least one type of resin. A ratio of resin pressure Cp2 at the foaming part of the metal mold relative to resin pressure Cp1 generated by the extruder is 0.3 or more.

A resin foam production apparatus is provided including: a metal mold including a foaming part and a discharge part; and an extruder configured to feed a resin foamable composition into the metal mold to cause the resin foamable composition to pass through the discharge part. The resin foamable composition comprises at least one type of resin. A ratio of resin pressure Cp2 at the foaming part of the metal mold relative to resin pressure Cp1 generated by the extruder is 0.3 or more.

Method for determining at least one layer property of a layer to be determined, in particular a foam layer, in an extrusion process, where a supply material is at least partially foamed and an extrusion product with the foam layer is put out (in other words, is output). The method has at least the steps of irradiating the extrusion product using electro-magnetic radiation, and electro-magnetically measuring at least one radiation having travelled through the foam layer. Measuring at least one feed-in rate or feed-in volume of the supply material, and determining the at least one material property of the layer to be determined from the measured feed-in volume and the electro-magnetic measurement.

A linear low density polyethylene (LLDPE) foam and methods of making the same are described. The LLDPE foam has a maximum operating temperature of about 220° F. The LLDPE foam can also have a density in the range of from 0.6 to 10.0 lbs/ft.sup.3. The LLDPE foam can be manufactured in part by processing an LLDPE resin in order to create a long branch molecular structure in the LLDPE resin without crosslinking or otherwise adversely affecting the thermoplastic properties of the LLDPE resin.

A linear low density polyethylene (LLDPE) foam and methods of making the same are described. The LLDPE foam has a maximum operating temperature of about 220° F. The LLDPE foam can also have a density in the range of from 0.6 to 10.0 lbs/ft.sup.3. The LLDPE foam can be manufactured in part by processing an LLDPE resin in order to create a long branch molecular structure in the LLDPE resin without crosslinking or otherwise adversely affecting the thermoplastic properties of the LLDPE resin.

A linear low density polyethylene (LLDPE) foam and methods of making the same are described. The LLDPE foam has a maximum operating temperature of about 220° F. The LLDPE foam can also have a density in the range of from 0.6 to 10.0 lbs/ft.sup.3. The LLDPE foam can be manufactured in part by processing an LLDPE resin in order to create a long branch molecular structure in the LLDPE resin without crosslinking or otherwise adversely affecting the thermoplastic properties of the LLDPE resin.

A linear low density polyethylene (LLDPE) foam and methods of making the same are described. The LLDPE foam has a maximum operating temperature of about 220° F. The LLDPE foam can also have a density in the range of from 0.6 to 10.0 lbs/ft.sup.3. The LLDPE foam can be manufactured in part by processing an LLDPE resin in order to create a long branch molecular structure in the LLDPE resin without crosslinking or otherwise adversely affecting the thermoplastic properties of the LLDPE resin.