A process for producing split crosslinked polyolefin sheets comprises producing a crosslinked polyolefin foam sheet having an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region, and an average cell size larger than an average cell size of the first surface region and the second surface region; and applying a splitting force to the crosslinked foam sheet such that a controlled tear propagation travels through the intermediate region until a first side of the crosslinked polyolefin foam sheet and a second side of the crosslinked polyolefin foam sheet are separated to produce two split polyolefin foam sheets. The split crosslinked polyolefin foam sheets may comprise a skin side comprising a closed cell surface, and a split side comprising an open cell surface having peak heights of about 150 μm to about 550 μm.

In order to provide a manufacturing method of an elongated foam sheet capable of manufacturing the elongated foam sheet with highly-precise thickness without being limited by the material and thickness of foam material, a method of manufacturing an elongated foam sheet includes performing a slice process in which a foam sheet is created by slicing a foam block and a sheet pasting process in which a large number of foam sheets are arranged and pasted onto one side of an elongated base material sheet to manufacture the elongated foam sheet where the large number of foam sheets are lined up in a longitudinal direction of the base material sheet.

Prepare an extruded polystyrene foam that is characterized by being a singular polymer foam that is free of halogenated blowing agents, having a milled primary surface, having a width of 750 millimeters or more, and further characterized by having a ρ(CST/CSP) value that is 50 kilograms per cubic meter or less and a milled primary surface.

A closed cell crosslinked polyolefin foam sheet comprises an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region to enable a controlled tear propagation within the intermediate region when a splitting force is applied to the closed cell crosslinked polyolefin foam sheet. For example, a ratio of a gel content of the intermediate region versus an average gel content of the first surface region and the second surface region may be about 75% or less, and a ratio of the average cell size of the intermediate region versus an average cell size of the first surface region and the second surface region may be about 125% or higher.

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.

The invention relates to a contoured structural element (100) for use as a core layer in a curved sandwich composite element, the contoured structural element (100) being formed from a thermoplastic foam, in particular PET, the contoured structural element (100) being subdivided, except for a connecting layer (12), into a plurality of body elements (10), and the body elements (10) and the connecting layer (12) being aligned parallel to a base area (26) of the contoured structural element (100) which is in a planar state. According to the invention, at least one surface layer (16) of the connecting layer (12) and the adjoining surface layer (18) of the body elements (10) at least partly have a thermally densified layer (14); the body elements (10), the connecting layer (12) and the thermally densified layer (14) being made of the same material.

Methods of forming polymeric foams are provided. The methods may involve co-extruding a foam layer along with one or more skin layers. In some embodiments, the skin layer(s) may be removed (e.g., in a peeling operation); while, in other embodiments, the skin layer(s) may form part of the final article. The methods are particularly well suited for producing polymeric foams from polymeric materials that are considered to be difficult to foam by those of skill in the art.

A rigid polymer foam having specific characteristics in terms of resin absorption, and a structural element made from such rigid polymer foam and adapted to be used as a core layer in a multilayer structural element.

A process for producing split crosslinked polyolefin sheets comprises producing a crosslinked polyolefin foam sheet having an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region, and an average cell size larger than an average cell size of the first surface region and the second surface region; and applying a splitting force to the crosslinked foam sheet such that a controlled tear propagation travels through the intermediate region until a first side of the crosslinked polyolefin foam sheet and a second side of the crosslinked polyolefin foam sheet are separated to produce two split polyolefin foam sheets. The split crosslinked polyolefin foam sheets may comprise a skin side comprising a closed cell surface, and a split side comprising an open cell surface having peak heights of about 150 μm to about 550 μm.

A closed cell crosslinked polyolefin foam sheet comprises an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region to enable a controlled tear propagation within the intermediate region when a splitting force is applied to the closed cell crosslinked polyolefin foam sheet. For example, a ratio of a gel content of the intermediate region versus an average gel content of the first surface region and the second surface region may be about 75% or less, and a ratio of the average cell size of the intermediate region versus an average cell size of the first surface region and the second surface region may be about 125% or higher.