The electret-treated sheet includes: a core layer (A) which is a porous film containing at least a thermoplastic resin; a surface layer (X) disposed on one side of the core layer (A); and a back surface layer (Y) disposed on the other side of the core layer (A), the surface layer (X) and the back surface layer (Y) each having a charged outermost surface, wherein the electret-treated sheet has a water vapor permeability coefficient of 0.1 to 2.5 g.Math.mm/m.sup.2.Math.24 hr; the core layer (A) has a pore aspect ratio of 5 to 50 and an average pore height of 2.5 to 15 μm; the surface layer (X) and the back surface layer (Y) each have a thickness of 5 to 200 μm; and the surface layer (X) includes a heat seal layer (B) including the outermost surface, wherein the heat seal layer (B) has a melting point of 50 to 140° C.

A multilayer foam film comprising high density polyethylene for direct and non-direct food contact and aseptic packaging application is disclosed. In an embodiment, the film has a bulk density of less than 0.962 gr/cm.sup.3 wherein more than 50% of the cells in the foam layer are closed cells. In an embodiment, the foam films are thick (generally more than 8 mils thick) and have a bending stiffness value of more than 18, in Taber stiffness unit configuration according to TAPPI/ANSI T 489 om-15, and the ratio of the mass per unit area (the mass of a unit area of the film in gram per meter-squared (gr/m.sup.2)) over the stiffness value in Taber unit configuration is equal to or less than 13. In an embodiment, the film has a very smooth surface with a smoothness value of less than 25 in Sheffiled smoothness unit configuration according to TAPPI T 538. The described foam film can have a water vapor transmission rate value of less than 1 gr/m.sup.2/24 hr, according to ASTM E398-13. The described foam film can have an oxygen transmission rate value of less than 10 cc/m.sup.2/24 hr, according to ASTM D3985.

The present invention provides a continuous process for solid-state expansion of a biopolymer, e.g., polylactic acid, which can be used to manufacture reduced-density thermoplastic materials with improved physical and thermal properties. By incorporating multiple stages of heating into the process as a means to regulate heat flux, unprecedented control of microstructure and crystallinity can be achieved. Thermoplastic sheets with the distinct cellular characteristics imparted by the process disclosed herein were found to be thicker and stronger than materials prepared by conventional processes. Thermoforming sheets with such characteristics enabled the production of light-weight, thermally-stable, compostable products that resist warping, and are thus suitable for a range of industrial applications.

A display device includes a display panel and a cushion layer disposed below the display panel. The cushion layer includes a first foam layer having a first density, a second foam layer disposed above the first foam layer and having a second density less than the first density, and a third foam layer disposed above the second foam layer and having a third density greater than the first density. The third form layer is disposed closer to the display panel than the first foam layer. The display device provides improved surface quality, impact resistance, and restoration properties.

A composite panel structure has opposing outer walls or surfaces and a core comprising a plurality of ribs extending between and connected to the outer walls and defining chambers which are filled with expanding foams, non-expanding foams, gases, or a combination thereof. The outer panel surfaces and internal chamber walls or ribs are made of woven or non-woven fibrous material impregnated with one or more resins. The panel structure may be used for making a variety of products including sports equipment such as sports paddles, surfboards, kite boards, skateboards, wakeboards, as well as construction panels for walls, ceilings or floors, display panels, panels for the vehicle industry, furniture, and other structures requiring high strength to weight properties.

A method for manufacturing a closed porous composite material includes 1) preparing a mixture that has 30 to 70 parts by weight of water-dispersed resin, 10 to 300 parts by weight of unexpanded thermal expansion microspheres, and 100 to 550 parts by weight of water, and stirring the mixture thoroughly; 2) preparing a carrier; 3) coating the carrier with the mixture acquired in step 1; 4) heating the carrier so that the unexpanded thermal expansion microspheres expand; and 5) repeating steps 3 and 4 multiple times to acquire a closed porous composite material. The closed porous composite material has a large number of closed cavities and polymer walls separating the closed cavities. The closed cavity is 20 μm to 800 μm in size. The ratio of a total volume of the closed cavities to a total volume of the polymer walls is greater than 16.

Disclosed, among other things, are ways to manufacture reduced density thermoplastics using rapid solid-state foaming and machines useful for the saturation of plastic. In one embodiment, a foaming process may involve saturating a semi-crystalline polymer such as Polylactic Acid (PLA) with high levels of gas, and then heating, which may produce a reduced density plastic having high levels of crystallinity. In another embodiment, a foaming process may produce layered structures in reduced density plastics with or without integral skins. In another embodiment, a foaming process may produce deep draw structures in reduced density plastics with or without integral skins. In yet another embodiment, a foaming process may utilize additives, blends, or fillers, for example. In yet another embodiment, a foaming process may involve saturating a semi-crystalline polymer such as Polylactic Acid (PLA) with high levels of gas, and then heating, which may produce a reduced density plastic having high levels of crystallinity.

Described herein are physically crosslinked, closed cell continuous multilayer foam structures that includes a foam layer comprising polypropylene, polyethylene, or a combination of polypropylene and polyethylene and a polyamide cap layer. The multilayer foam structure can be obtained by coextruding a multilayer structure comprising at least one foam composition layer and at least one cap composition layer, irradiating the coextruded structure with ionizing radiation, and continuously foaming the irradiated structure.

A composite panel structure has opposing outer walls or surfaces and a core comprising a plurality of ribs extending between and connected to the outer walls and defining chambers which are filled with expanding foams, non-expanding foams, gases, or a combination thereof. The outer panel surfaces and internal chamber walls or ribs are made of woven or non-woven fibrous material impregnated with one or more resins. The panel structure may be used for making a variety of products including sports equipment such as sports paddles, surfboards, kite boards, skateboards, wakeboards, as well as construction panels for walls, ceilings or floors, display panels, panels for the vehicle industry, furniture, and other structures requiring high strength to weight properties.

A thermal insulation article includes a thermally insulating pad shaped to be positioned in a cavity of a rectangular prism shipping container. The pad includes a solid compostable panel formed primarily of starch and/or plant fiber pulp that holds together as a single unit, and a water-proof or water-resistant film forming a pocket enclosing the panel. The panel includes a first section, a second section, and a third section connecting the first section to the second section, the first and second section each having a central portion and two flaps that extend from the central portion beyond the third section, and wherein the panel is foldable into an open box.