摘要:
A plastic melt is treated for a short-time with a liquid treatment agent under pressure, it is divided into defined subquantities, individual subquantities are brought into contact with a treatment agent and combined for a residence time of less than one second with portions of at least one other subquantity, and portions of the mixture thus formed are separated and combined with another subquantity; the steps of dividing and combining the mixture are repeated several times at intervals of less than one second until an intimate mixture of the plastic melt and the treatment agent has formed, allowing the preparation of especially homogeneously structured thermoplastic materials, e.g., poly(methacrylalkylimide) plastics, which are compatible with poly(methyl methacrylate).
摘要:
A method is disclosed for biaxially stretching a band of thermoplastic resin which comprises attenuating a band of unstretched resin, in a forming zone while the resin is in the thermoelastic condition, by passing the band between two surfaces spaced at a distance less than the thickness of said band of unstretched resin while permitting said band to expand in width, and then cooling said band to a temperature below the softening point of the resin while maintaining the dimensions of the attenuated and expanded band; apparatus for performing such a method is also disclosed.
摘要:
Homogeneous polymer mixtures of polymethacrylimides consist of a component (A), composed of from 30 to 90 percent by weight of methacrylalkylimide units and from 3.5 to 10 percent by weight of methacrylic acid units, and of a component (B1) or (B2) having from 10 to 50 percent by weight more methacrylalkylimide units than component (A), component (B1) having a degree of imidization of less than 95 percent and containing from 3.5 to 10 percent by weight of methacrylic acid units, and component (B2) having a degree of imidization greater than 95 percent and containing less than 3.5 percent by weight of methacrylic acid units.
摘要:
The invention relates to a method for dehydrating a two-phase liquid mixture consisting of a thermoplastic synthetic melt phase and an aqueous phase, comprising the following steps: a) coagulation of the two-phase liquid mixture in a first extruder; b) dehydration of the coagulate in a twin screw extruder with a de-watering zone and screws working in an opposite direction; c) separation of constituents by degasifying. The inventive method is characterized in that a single screw extruder or a twin screw extruder with screws working in the same direction is used as a first extruder in step a).
摘要:
Heat exchanger or heat accumulator bodies which are simple to produce. The bodies consist of a stack of extruded hollow chamber panels with plane smooth outer walls and webs that join the outer walls in a single piece. The hollow chamber panels are joined to one another in the stack on the front side by locking connections. The locking connections can be produced with an inserted electrical band heater, by glue seams, or by undercut interlockings. The hollow chamber panels are not joined to one another in the in-between areas or are not everywhere joined in the in-between areas.
摘要:
What is disclosed is a method for making a gastight multiple-walled panel of extruded resin from an integrally extruded hollow panel comprising two parallel, plane outer walls having supporting partitions disposed between them and defining long hollow cells with open end faces, which method comprises heating the hollow panel at least in the area of the open end faces of said hollow cells until the resin is in the thermoplastic state, and then heat sealing the two outer walls in the thermoplastic area thereof in a gastight manner either to each other or to a tape of a further thermoplastic material covering the end faces, the seal so produced being held for at least 1 minute at a temperature ranging from 10.degree. C. beneath the Vicat softening point to 20.degree. C. above the Vicat softening point of the resin.
摘要:
A two phase liquid mixture of a thermoplastic synthetic resin melt and an aqueous phase, such as a latex coagulate, is dewatered in a counter-rotating twin screw extruder under a pressure which is greater that the water vapor pressure at the temperature of the melt of the thermoplastic synthetic resin by conveying the melt into partially filled screw channels in the dewatering zone and restricting it in at least one of these screw channels in the entry nip of the twin screws to create a local, narrowly limited, steep pressure gradient and to form a coherent melt cake, and draining the water in liquid form from beneath under gravity upstream from the boundary of the melt cake so that the melt cake does not stand in contact with a coherent aqueous phase.
摘要:
Molding compositions MC having a reduced tendency to yellow with thermal stress which consist of a polymer PM containing units of formula I: ##STR1## blending from 0.005-1 wt % of at least one reducing inorganic phosphorus compound IP selected from the group consisting of phosphinic and phosphonic acid and its alkali metal, alkaline-earth metal, a aluminum and ammonium salts, wherein the ammonium ion can be substituted with up to four C.sub.1 -C.sub.4 alkyl and/or C.sub.5 -C.sub.8 cycloalkyl groups, with the polymer PM after conclusion of the imidation reaction.
摘要:
The invention relates to a method for reducing the polymer content in the wastewater from dewatering of two-phase liquid mixtures comprising a thermoplastic plastic melt and an aqueous phase by coagulating the plastic melt and pressing the water out of the melt cake in an extruder system, characterized in that superheated steam with a temperature of at least 280° C. is injected immediately after introduction of the two-phase liquid mixture into the extruder system.
摘要:
Processes for producing moldings by injection moulding, include melting a mixture made from a (meth)acrylate copolymer and a release agent, devolatilizing the mixture, injecting the molten and devolatilized mixture into a mold cavity of an injection mold, cooling the molten mixture, and removing the resultant molding from the mold.