Abstract:
The invention relates to a method for producing expandable styrene polymers, which method comprises the following steps: (a) adding an aqueous phase containing a suspension stabilizer and an organic phase containing styrene and initiator to a reactor, (b) starting the addition of a blowing agent at a conversion rate of styrene in the range from 40 to 70% and addition of the blowing agent over a period of 30 to 60 minutes, (c) adding a stabilizer for stabilizing the bead size distribution of the expandable styrene polymer at a conversion rate of styrene in the range from 65 to 99%.
Abstract:
A process for production of expandable styrene polymers with narrow bead-size distribution with high specific reactor yield via polymerization of the monomers in aqueous suspension in a stirred tank in the presence of a volatile blowing agent, where the styrene-containing organic phase is added simultaneously with the aqueous phase to the stirred tank over a period of from 5 to 60 minutes.
Abstract:
The invention relates to a method and a device for granulating polymer melts containing blowing agent in a granular heating chamber, through which there flows a liquid at a pressure above ambient pressure. In a first step, the polymer melt is forced into the granulating chamber, in a second step the polymer melt is cut by a cutting device into individual granular grains and in a third step the granular grains produced in the granulation are discharged with the liquid from the granulating chamber and separated from the liquid. The method additionally comprises at least one of the following steps: (a) comminuting agglomerates or granular grains that exceed a predetermined maximum size, in a comminuting machine arranged downstream of the granulating chamber or in a comminuting unit arranged downstream of the cutting device, (b) allowing the liquid to expand in an expansion machine, (c) allowing the liquid to expand in a throttle device, a pressure equalizing tank being arranged upstream of the throttle device, (d) separating the granular grains from the liquid without previously allowing the liquid to expand with the granular grains contained in it.
Abstract:
The invention relates to styrene polymer beads, characterized in that the styrene polymer beads contain 0.5 to 5 wt % of one or more high-temperature peroxides, wherein the high-temperature peroxides have a half-value period of one hour in the range of 110 to 160⁰C, measured in cumene.
Abstract:
The invention relates to a method and a device for granulating polymer melts containing blowing agent in a granular heating chamber, through which there flows a liquid at a pressure above ambient pressure. In a first step, the polymer melt is forced into the granulating chamber, in a second step the polymer melt is cut by a cutting device into individual granular grains and in a third step the granular grains produced in the granulation are discharged with the liquid from the granulating chamber and separated from the liquid. The method additionally comprises at least one of the following steps: (a) comminuting agglomerates or granular grains that exceed a predetermined maximum size, in a comminuting machine arranged downstream of the granulating chamber or in a comminuting unit arranged downstream of the cutting device, (b) allowing the liquid to expand in an expansion machine, (c) allowing the liquid to expand in a throttle device, a pressure equalizing tank being arranged upstream of the throttle device, (d) separating the granular grains from the liquid without previously allowing the liquid to expand with the granular grains contained in it.
Abstract:
The invention relates to expanded particulate moulded parts with a density ranging between 10 and 100 g/l. Said parts are obtained by welding pre-expanded particulate consisting of expandable thermoplastic polymer granulates, the latter containing between 5 and 100 wt. % styrene copolymer A), between 0 and 95 wt. % polystyrene B) and between 0 and 95 wt. % thermoplastic polymer C) that differs from a) and b). The invention also relates to methods for producing the expandable thermoplastic polymer granulates.
Abstract:
The invention relates to expandable polystyrene granulates with at least a bi- or multi-modal molecular-weight distribution, to a method for producing said granulates and to their use in the production of expanded particulate moulded parts.
Abstract:
The invention relates to a composition containing at least one expandable styrene polymer component and at least one cyclohexane carboxylic acid ester, and optionally other components. Said composition can be processed to form mechanically loadable foams.
Abstract:
A process for preparing expandable styrene polymers with narrow bead size distribution, which can be processed to foams with homogeneous cell structure and low thermal conductivity, by polymerizing the monomers in aqueous suspension in the presence of a volatile blowing agent and from 0.1 to 30 ppm, based on the organic phase, of a hydroxyalkylamine.