Injection molding methods used to form polymeric foam articles (e.g., microcellular foam articles) are described herein.

Provided is a low-dielectric porous polymer film having a low dielectric constant at high millimeter-wave frequencies and thereby useful as a sheet for a millimeter-wave antenna. The low-dielectric porous polymer film comprises: a base material layer made of a polymer material and formed with fine pores dispersed therein; and a substantially smooth skin layer made of the same polymer material as that of the base material layer and formed on at least one of the surfaces of the base material layer.

The present invention relates to a crash pad for a vehicle and a manufacturing method thereof. In one embodiment, the method for manufacturing the crash pad for the vehicle comprises a step of injecting a skin foam-forming composition between a lower mold having a color coating layer formed thereon and an upper mold having a core layer formed thereon, foaming the injected skin foam-forming composition to form a skin foam layer, wherein the color coating layer is formed by applying the color coating composition to the inside surface of the lower mold and curing the applied color coating composition.

The present invention relates to a crash pad for a vehicle and a manufacturing method thereof. In one embodiment, the method for manufacturing the crash pad for the vehicle comprises a step of injecting a skin foam-forming composition between a lower mold having a color coating layer formed thereon and an upper mold having a core layer formed thereon, foaming the injected skin foam-forming composition to form a skin foam layer, wherein the color coating layer is formed by applying the color coating composition to the inside surface of the lower mold and curing the applied color coating composition.

A molded body includes a non-foamed design layer, a foamed intermediate layer, and a non-foamed back layer, laminated in this order and formed of a first, second, and third resin compositions, respectively. The first, second, and third resin compositions contain a polyolefin as a main component. The first resin composition is an impact-resistant resin composition including a polyolefin, a polyamide, and a polyolefin-based modified elastomer having a reactive group reactive with the polyamide. A method of producing the molded body includes disposing a first support layer to serve as the design layer and a third support layer to serve as the back layer so as to be spaced apart from and face each other, interposing the second resin composition provided with foamability in a gap between the first and third support layers, and forming the intermediate layer by expanding the gap while causing the second resin composition to foam.

A molded body includes a non-foamed design layer, a foamed intermediate layer, and a non-foamed back layer, laminated in this order and formed of a first, second, and third resin compositions, respectively. The first, second, and third resin compositions contain a polyolefin as a main component. The first resin composition is an impact-resistant resin composition including a polyolefin, a polyamide, and a polyolefin-based modified elastomer having a reactive group reactive with the polyamide. A method of producing the molded body includes disposing a first support layer to serve as the design layer and a third support layer to serve as the back layer so as to be spaced apart from and face each other, interposing the second resin composition provided with foamability in a gap between the first and third support layers, and forming the intermediate layer by expanding the gap while causing the second resin composition to foam.

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 ?m to about 550 ?m.

The present invention provides a foamable resin composition excellent in terms of the dispersibility and moldability. The foamable resin composition containing: from 30 to 80 wt % of a polyolefin; from 3 to 40 wt % of a polylactic acid; from 1 to 20 wt % of a modified polyolefin containing a carbonyl group in a molecule; from 10 to 40 wt % of a layered silicate; and from 0.01 to 0.5 wt % of a filler, the polyolefin containing at least one of polypropylene and polyethylene, the filler having a density different from the density of the layered silicate by at least 0.20 g/cm.sup.3.

The present invention provides a foamable resin composition excellent in terms of the dispersibility and moldability. The foamable resin composition containing: from 30 to 80 wt % of a polyolefin; from 3 to 40 wt % of a polylactic acid; from 1 to 20 wt % of a modified polyolefin containing a carbonyl group in a molecule; from 10 to 40 wt % of a layered silicate; and from 0.01 to 0.5 wt % of a filler, the polyolefin containing at least one of polypropylene and polyethylene, the filler having a density different from the density of the layered silicate by at least 0.20 g/cm.sup.3.

The invention pertains to a process for manufacturing a glycerol-tricarboxylic acid polyester foam which comprises the steps of combining glycerol and a tri-carboxylic acid to provide a liquid reaction mixture and contacting the reaction mixture with a substrate under polymerization conditions, wherein the substrate has a top layer comprising one or more of metal, metal oxide, and metal halide. The invention also pertains to a glycerol-tricarboxylic polyester foam, in particular a glycerol-citric acid polyester foam, which has a closed cell foam structure wherein at least 90 vol. % of the foam, preferably at least 95% of the foam, is built up from cells having a diameter below 2 mm. The foamed polyester of the present invention is green, biodegradable, and non-toxic, and can be cleanly combusted. It finds application in, int. al., packaging materials, insulation materials, and materials with a short life cycle.