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:
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:
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:
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.
摘要:
The invention relates to a process for making molded articles by means of injection molding with the process steps of a) melting of a (meth)acrylate copolymer, which is composed of 30 to 80 wt % of radical-polymerized C1 to C4 alkyl esters of acrylic or methacrylic acid and 70 to 20 wt % of (meth)acrylate monomers with a tertiary ammonium group in the alkyl residue, wherein the (meth)acrylate copolymer is present in a mixture with 1 to 70 wt % of a plasticizer and a desiccant in the ratio of 1:1 to 1:20 and also with 0.05 to 5 wt % of a release agent, and further standard additives or adjuvants and if necessary even a pharmaceutical active principle can also be present in the mixture, and before the mixture is melted it has a content of more than 0.5 wt % of low-boiling constituents with a vapor pressure of at least 1.9 bar at 120° C., b) degassing of the mixture in the thermoplastic condition at temperatures of at least 120° C., whereby the content of low-boiling constituents with a vapor pressure of at least 1.9 bar at 120° C. is lowered to at most 0.5 wt % and c) injection of the melted and degassed mixture into the mold cavity of an injection-molding die, wherein the mold cavity has a temperature which lies at least 10° C. below the glass transition temperature of the (meth)acrylate copolymer, cooling of the melt mixture and removal of the obtained molded article from the mold.
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:
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, 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 present invention relates to a process for preparing aqueous dispersions. The invention also relates to the formation of core-shell particles in aqueous dispersions. The core-shell particles are useful as impact-modifiers for poly(meth)acrylate moulding compositions.
摘要:
The present invention relates to a process for preparing aqueous dispersions. The invention also relates to the formation of core-shell particles in aqueous dispersions. The core-shell particles are useful as impact-modifiers for poly(meth)acrylate moulding compositions.