Abstract:
A method for producing food packagings from biodegradable foam material, in particular trays for use as disposable plates or dishes, is described. This involves providing a starting material that consists of or contains an organic cellulose ester or mixed cellulose ester, in particular cellulose acetate, and subjecting the starting material to a pretreatment to reduce the moisture content. By the beginning of the subsequent melting process, the moisture content is kept to, or below, a fixed limit. The pretreated starting material is melted and subsequently made to expand to obtain a foam material of a flat form. This is then followed by the foam material obtained being stored, to allow a second foaming agent to diffuse into it, and heated, in order to bring about renewed expansion. The heated foam material is thermoformed to form the food packaging.
Abstract:
The present invention relates to a process for the production of a geopolymer composite. It further relates to a geopolymer composite, and the use of a geopolymer, a geopolymer in combination with an athermanous additive, or the geopolymer composite in expanded vinyl polymer, preferably vinyl aromatic polymer. Furthermore, the invention relates to a process for the production of expandable vinyl aromatic polymer granulate, and expandable vinyl aromatic polymer granulate. Finally, the present invention relates to expanded vinyl foam, preferably vinyl aromatic polymer, and to a masterbatch comprising vinyl polymer and a), b), or c).
Abstract:
The invention relates to a method for producing prefoamed poly(meth)acrylimide (PMI) particles, which can be further processed into foam-moulded parts or composites. The method is thereby characterized in that a polymer granulate is initially heated in a device by means of infrared radiation at a wavelength suitable for this purpose and is thus prefoamed. In subsequent method steps, e.g. in a pressing tool, this granulate can be further processed, by foaming, into a moulded part or a composite workpiece with a foam core.
Abstract:
The invention relates to a process for the production of expanded foam beads made of pellets comprising a polyester mixture composed of: • a) from 50 to 99% by weight, based on components a and b, of a biodegradable polyester based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, and • b) from 1 to 50% by weight, based on components a and b, of polylactic acid, comprising the following steps: • (i) production of a suspension comprising pellets of the polyester mixture in a suspension medium, • (ii) impregnation of the pellets comprised in the suspension from step (i) with at least one physical or chemical blowing agent, in order to obtain blowing-agent-loaded pellets in suspension, by heating the mixture to the depressurization temperature IMT, with stirring, and • (iii) after expiry of a retention time, depressurization of the suspension obtained in step (ii), in order to obtain expanded foam beads, which comprises proceeding in an aqueous suspension medium, adding the blowing agent in step (i) or in step (ii) during the heating phase or immediately after the heating phase and, in step (ii), after heating, keeping the suspension for from 3 to 100 minutes at a temperature in the range from IMT minus 5°C to IMT plus 2°C. The invention further relates to expanded foam beads obtainable by said process, and also to the production of moldings from said foam beads.
Abstract:
The invention relates to a method for producing expanded foam particles from a granular material, which contains at least one biodegradable polyester, which can be obtained from the following by polycondensation: A1) 40 to 60 mol%, with respect to components A1) to A2), of a succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic acid, or the respective ester-forming derivatives of said acids or mixtures thereof, A2) 40 to 60 mol%, with respect to components A1 to A2), of a terephthalic acid or the ester-forming derivative thereof, B) 98.5 to 100 mol%, with respect to components A1) to A2), of 1,4-butanediol or 1,3-propanediol or mixtures thereof; and C) 0.05 to 1.5 wt%, with respect to components A1) to A2) and B), of a compound or of a plurality of compounds selected from the group comprising: C1) a compound having at least three groups capable of ester formation, C2) a di- or polyfunctional isocyanate, C3) a di- or polyfunctional epoxide; comprising the following steps: (i) producing a suspension containing a granular material in a suspending medium, (ii) impregnating the granular material contained in the suspension from step (i) with at least one physical blowing agent in order to obtain a blowing-agent-laden granular material in suspension, by heating up the mixture to the relaxation temperature IMT while the mixture is stirred, and (iii) relaxing the suspension obtained in step (ii) after the expiration of a holding time and cooling the relaxed suspension by means of a liquid aqueous coolant in order to obtain expanded foam particles, characterized in that the method is performed in a suspending medium containing water, the blowing agent is added in step (i) or in step (ii) during the heat-up phase or immediately after the heat-up phase, and in step (ii) the suspension is held at a temperature in the range of IMT minus 5°C to IMT plus 2°C for 3 to 100 minutes after the heat-up, and the quantity ratio of coolant to suspending medium is at least 0.3. The invention further relates to expanded foam particles that can be obtained in accordance with said method and to the production of molded parts made of said foam particles.