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.

Present invention is related to a microwave and electromagnetic heated foaming method, mold and foaming material thereof. The microwave and electromagnetic heated foaming method comprises steps of adding a foam material into a mold, simultaneously applying a microwave and electromagnetic energy toward the mold under a normal or low pressure, and the microwave and electromagnetic energy made the foam material into molded foam body. The mold of the present invention has a microwave penetrating part and an electromagnetic heating part. The microwave penetrating part has an extruded bottom that is corresponded to a dented top of the electromagnetic heat penetrating part. By utilizing the microwave and electromagnetic energy, the present invention is about to provide an efficient way for processing the foaming material compared to the conventional infrared or electrical heated tube heating and achieve the foam method that can be executed under normal or low pressure.

A polyolefin-based resin foamed sheet includes a polyolefin-based resin, wherein a thickness of the foamed sheet is 0.05-0.5 mm, an apparent density is 200-500 kg/m.sup.3, a tensile strength at 100% elongation in at least one direction of a longitudinal direction (MD direction) and a width direction (TD direction) of the sheet is 3.5-12 MPa, and a ratio of a tensile breakage strength and the tensile strength at 100% elongation in at least one direction of the MD direction and the TD direction of the sheet is 1.0-1.8.

A process for producing a polymeric article is provided that includes: sequentially filling a female mould (11) with a first, second, and third batches, wherein the first and third batches include first and third polymeric materials (1p, 3p), and the second batch includes a second polymeric material (2p) and a blowing agent (2b), closing the thus filled cavity with a lid (12) to form a mould defining a closed cavity (10c) of constant volume in time, heating the mould (10) to a processing temperature, to melt the first, second, and third polymeric materials (1p-3p) and to expand the second polymer agent by activation of the blowing agent, cooling and removing the lid (12) to open the cavity and extracting the polymeric article. At least the second polymeric material (2p) includes at least 50 wt. % of recycled polymer in the form of shredded flakes.

A foam composition comprises a recycled polyvinyl butyral in an amount from 5 wt % to 70 wt %; an ethylene-ester copolymer in an amount from 10 wt % to 70 wt %; a foaming agent in an amount from 0.5 wt % to 3.5 wt %; a peroxide crosslinking agent in an amount from 0.5 wt % to 3.0 wt %; and a hydrazide crosslinking agent in an amount from 0.1 wt % to 2.5 wt %, based on a total weight of the foam composition. A foam produced from the foam composition can avoid emitting an unpleasant odor of aldehydes, and the foam also has good mechanical properties and good resilience.

A porous sound absorbing material having an average cell size of 100 to 600 μm and an apparent density of 40 to 140 kg/m.sup.3. A sound absorption method using this porous sound absorbing material.

The present invention provides a thermally expandable microcapsule having excellent heat resistance and high expansion ratio and enabling production of a light, high-hardness molded article having excellent physical properties (abrasion resistance), and a composition for foam molding containing the thermally expandable microcapsule. Provided is a thermally expandable microcapsule including: a shell containing a polymer; and a volatile expansion agent as a core agent encapsulated by the shell, the shell containing silicon dioxide and a polymer obtained by polymerizing a monomer composition containing a carbonyl group-containing monomer, the thermally expandable microcapsule having a ratio of a peak intensity based on a C═O bond in the shell to a peak intensity based on the silicon dioxide in the shell (peak intensity based on C═O bond/peak intensity based on silicon dioxide) of 0.25 to 1.0 as determined by IR spectral analysis, the thermally expandable microcapsule having a maximum foaming temperature (Tmax) of 180° C. to 225° C.

Compositions are provided including an uncrosslinked thermoplastic nitrogen-containing matrix material and composite particles distributed in the matrix material. The composite particles each include a chemical blowing agent particle encapsulated within a shell including an uncrosslinked thermoplastic material. The uncrosslinked thermoplastic material exhibits at least a certain minimum complex viscosity at a decomposition temperature of the chemical blowing agent particle. Also described are foam compositions and particles including the foam compositions, such as a sheet or multilayer construction. Composite particles are further provided. Methods of making the foam compositions are additionally described herein. Also, polishing pads, polishing systems, and methods of polishing a substrate are provided.

[Problem] An object of the present invention is to provide a foam including a thermoplastic resin and rubber as a main component, in which a micronized product of a cellulose fiber is uniformly dispersed, and uniformity and mechanical properties are excellent. [Solution] A foam includes a modified cellulose fiber (A) covalently bonded with a diene-based polymer, a thermoplastic resin and/or rubber (B), and a diene-based polymer (C) having a functional group capable of covalently bonding with a cellulose fiber, in which the fiber (A) is micronized, the fiber (A) has a content of 0.05 to 20% by mass, and the thermoplastic resin and/or rubber (B) has a glass transition point of −130° C. to 120° C.

A process of foaming a polyolefin, e.g., polyethylene, composition using as a nucleator a combination of (A) azodicarbonamide, and (B) a mixture of (1) a first component consisting of at least one of citric acid and an alkali metal citrate, and (2) a second component consisting of at least one of an alkali metal citrate, a di-alkali metal hydrogen citrate, an alkali metal dihydrogen citrate and an alkali metal bicarbonate, with the proviso that the mixture is not solely composed of alkali metal citrate.