Abstract:
The invention relates to a method for producing nanoporous polymer foam materials, having the steps of a) loading a polymer melt, which consists of thermoplastic polymers and a CO2-philic additive that is soluble in polymer, with a blowing agent at a pressure and at a temperature at which the blowing agent is in the supercritical state, b) controlling the temperature of the loaded polymer melt to a temperature that ranges from 40 °C below to 40 °C above the unloaded polymer melt glass transition temperature, which can be ascertained by means of DSC at a heating rate of 20 K/min in accordance with DIN-ISO 11357-2, and c) depressurizing the polymer loaded in step a) and temperature-controlled in step b) at a depressurization rate ranging from 15,000 to 2,000,000 MPa/sec. The invention also relates to the nanoporous polymer foam materials which can be obtained according to the method, said foam materials having a cell count ranging from 1,000 to 100,000 cells/mm 3 and a density ranging from 10 to 500 kg/m 3 , and to the use thereof in vacuum insulated panels.
Abstract:
The invention relates to a method for continuously producing nanoporous polymer foam materials, involving the following steps: a) producing a polymer melt from thermoplastic polymer and building up pressure in a single-screw extruder with a grooved barrel or in a twin-screw extruder with a downstream-connected gear pump to a pressure in the range of 20 to 200 MPa; b) loading the polymer melt with a blowing agent in a zone down-stream of the pressure build-up, which zone comprises mixing elements, at a temperature and at a pressure at which the blowing agent is in the supercritical state; c) controlling the temperature of the loaded polymer melt using cooling elements to a temperature in the range of 40 o C below to 40 o C above the glass transition temperature of the unloaded polymer melt, the glass transition temperature being determinable by means of DSC in accordance with DIN-ISO 11357-2 at a heating rate of 20 K/min; d) releasing the pressure of the polymer melt that was loaded in step b) and the temperature of which was controlled in step c) using a nozzle or nozzle plate at a pressure release rate in the range of 15,000 to 2,000,000 MPa/sec. The method also relates to the nanoporous polymer foam materials that can be obtained according to the method and have a cell count in the range of 1,000 to 100,000 cells/mm and a density in the range of 10 to 500 kg/m 3 .
Abstract:
The invention relates to a method for producing expandable thermoplastic polymer particles by post-impregnating thermoplastic polymer particles that contain at least one styrene polymer and at least one polyolefin, using a blowing agent. Said post-impregnation is predominantly carried out in the gas phase.
Abstract:
A process for producing expandable, thermoplastic polymer beads comprising cavities via extrusion of a polymer melt comprising blowing agent through a die plate and pelletization in a chamber comprising liquid under a pressure in the range from 1.5 to 15 bar, wherein the polymer melt comprising blowing agent comprises from 0.1 to 5% by weight of a nucleating agent D), from 1 to 10% by weight of a blowing agent E) which in essence remains within the polymer beads, from 0.01 to 5% by weight of a co-blowing agent F) forming the cavities, based in each case on the polymer melt comprising blowing agent, and also the expandable thermoplastic polymer bead material which can be obtained by the process, comprising cavities with an average diameter in the range from 0.1 to 50 µm.
Abstract:
The invention relates to a method for producing elastic, compressed foam based on melamine/formaldehyde resins, wherein a melamine/formaldehyde precondensate is foamed and the soft, non-cured melamine/formaldehyde foam is compressed and subsequently dried and optionally tempered.
Abstract:
Novel melamine/formaldehyde foams having microcapsules incorporated into the structure of the condensation products, and also a method for the production thereof and uses thereof.
Abstract:
The invention relates to a method for producing an elastic foam by means of foaming a mixture comprising 50 to 97 wt % of an aqueous dispersion A) of SiO 2 particles having an average particle diameter in the range of 1 to 100 nm, 1 to 45 wt % of a polymer dissolved in water, B) 1 to 50 wt % of a propellant, C) 1 to 5 wt % of an emulsifier, D) 0 to 5 wt % of a cross-linking agent capable of reacting with the polymer B), and the foam that can be obtained by means of the method, and to the use thereof.