摘要:
Expanded polyolefin particles are produced by impregnation of polyolefin granules with a volatile blowing agent in suspension under pressure and subsequent decompression. The blowing agent used is ammonia.
摘要:
The invention relates to a process for the preparation of bead shaped, expandable polystyrene by the polymerization of styrene in an aqueous suspension in the presence of dimeric .alpha.-methylstyrene as a regulator and a C.sub.3 to C.sub.6 hydrocarbon as a blowing agent, whereby one first reports the content of saturated hydrocarbons, having a boiling point between 70.degree. and 170.degree. C., in the styrene and dimeric .alpha.-methylstyrene, and then enough saturated hydrocarbons, having a boiling point from 70.degree. to 170.degree. C., are added before, during or after the polymerization so that their total content in the suspension is from 0.1 to 0.8 weight percent, based on the styrene.
摘要:
The invention relates to expandable styrene polymers containinga) a styrene polymer,b) and at least one carbon dioxide absorber, mixed or copolymerized with the above, in an amount of from 0.01 to 50% by weight, based on the sum of a) and b), andc) a blowing agent or blowing agent mixture in an amount of from 0.5 to 12% by weight,where the blowing agent or blowing agent mixture comprisesc.sub.1) from 10 to 100% by weight of carbon dioxide andc.sub.2) from 0 to 90% by weight of at least one further blowing agent.The invention furthermore relates to the styrene polymers containing a carbon dioxide absorber, to the styrene polymer foams obtainable from the expandable styrene polymers, and to an improved process for impregnating styrene polymers with carbon dioxide-containing blowing agents or blowing agent mixtures.
摘要:
Polyolefin foams having a density of from 0.01 to 0.1 g/cm.sup.3 and having 2 to 1000 cells/mm.sup.2 and containing a resin acid, a lower alkyl ester or a resin acid or (hydro) abietyl phthalate as organic foaming aid have a homogeneous cell structure.
摘要翻译:密度为0.01〜0.1g / cm 3,具有2〜1000个/ mm 2的含有树脂酸,低级烷基酯或树脂酸或邻苯二甲酸(氢化)邻苯二甲酸酯作为有机发泡助剂的聚烯烃泡沫具有均匀的电池结构 。
摘要:
An oil-resistant, expandable styrene polymer containsa) from 10 to 90% by weight of uncrosslinked polystyrene and/or an uncrosslinked styrene copolymer containing at least 50% by weight of copolymerized styrene,b) from 10 to 90% by weight of a crosslinked styrene polymer which contains at least 0.1% by weight, but less than 2% by weight, of a copolymerized monomer having at least two olefinic double bonds,c) from 1 to 10% by weight, based on the sum of a) and b), of a C.sub.3 - to C.sub.6 -hydrocarbon as blowing agent, and, if desired,d) conventional additives in effective amounts,the mixture of a) and b) having a melt flow index MFI (200.degree. C., 5.0 kp) in accordance with DIN 53 735 of from 1 to 20 [g/10 min].
摘要:
In order to dry finely divided, expandable styrene polymers having a particle size of from 0.02 to 3 mm, the bead polymers, in the form of a slurry in water, are freed from the majority of the water and subsequently exposed to a gaseous medium. The drying is carried out in two steps, by jointly conveying the bead polymer and a first gas stream, warmed to from about 45.degree. to 120.degree. C., through a flow dryer, the ratio between the gas and the bead polymer being from 2 to 40 kg/kg, separating the bead polymer from the first gas stream, immediately transferring the bead polymer into a fluidized bed and treating the polymer with a second gas stream at from about 0.degree. to 75.degree. C. Styrene polymers obtained in this way are free-flowing and can be foamed without difficulty in commercially available prefoaming units. They are used, inter alia, in the construction industry, for example as aggregate for insulation plaster.
摘要:
Bead-form expandable styrene polymers containing a styrene polymer having a mean molecular weight (weight average) of less than 130.multidot.10.sup.3 and a steep high-molecular-weight flank of the molecular-weight distribution curve, and 0.15 to 1.5 mol of a C.sub.3 - to C.sub.6 -hydrocarbon as blowing agent, and, if desired, customary additives in effective amounts, are distinguished by a particularly high expansion capacity.
摘要:
The invention is directed to a method for triggering switching functions in which the latter are triggered when the position signal emitted by a position transmitter exceeds or falls below a predeterminable signal level, the position signal being corrected and scaled in a signal-processing arrangement. A precise, long-term stable correspondence of the predeterminable signal level to a definite position of the position transmitter is assured in that the end values of the position signal corresponding to the two end stops are ascertained in a learning algorithm after each time the position transmitter is put into operation. The method is particularly suitable for triggering switching functions in a motor vehicle which has a position transmitter as a desired-value transmitter of an engine performance control or regulating system, the position transmitter being mechanically connected to the accelerator pedal of the vehicle. The triggering of the kick-down function, for example, for controlling the transmission of the vehicle occurs after a position of the accelerator pedal has been passed, the position always being located the same spacing ahead of the full-load stop. Mechanical tolerances and aging processes have no influence on this correspondence.
摘要:
Fine-celled foams are produced by a process in which a styrene polymer is melted, the melt is mixed with a volatile blowing agent and a nucleating agent under superatmospheric pressure, the mixture is let down to atmospheric pressure, and the foam is cooled. The nucleating agent employed comprises from 0.02 to 2% by weight of the calcium salt of a long-chain fatty acid, and from 0.01 to 1% by weight of a finely divided, inorganic substance which is insoluble in the styrene polymer, a mixture of calcium stearate and magnesium oxide being preferred.
摘要:
Particulate styrene polymers which contain a blowing agent and are surface-coated with from 0.05 to 1% by weight of an ester. The coating agent is a hydroxycarboxylic acid ester, or an ester of a carboxylic acid with an oxyalkylated alcohol; tristearyl citrate is a preferred ester.The styrene polymers can be used to produce foam moldings, with short mold dwell times and good welding of the foam particles.