摘要:
In a process for imidizing an alkyl methacrylate polymer by reaction with a nitrogen-containing imidizing agent, the formation of carboxyl and anhydride groups is suppressed when a portion of the imidizing agent is added only after the previously added imidizing agent has been reacted at least partially, and particularly when the reaction with the imidizing agent is terminated before the polymer has been completely imidized.
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:
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:
Injection molded parts having a scratch resistant surface are produced by applying a liquid mixture of at least one monomer susceptible of free radical polymerization and having more than one polymerizable double bond and of at least one free radical forming initiator to the forming surface of an injection mold, polymerizing the mixture at least partially, and then injecting a thermoplastic or duroplastic molding composition into the closed mold.
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:
The invention relates to the use of polyalkyl(meth)acrylate bead polymers with an average particle size V50 that ranges between 30 and 70 μm for improving the stress cracking resistance of moulding materials containing polyalkyl(meth)acrylate. The invention also relates to moulding materials comprising: a) at least 50 wt. % of an impact resistance modifying agent, which contains at least one polyalkyl(meth)acrylate phase; b) at least 8 wt. % of a polyalkyl(meth)acrylate bead polymer with an average particle size V50 that ranges between 30 and 70 μm; and c) between 0 and 42 wt. % of a polyalkyl(meth)acrylate with a molecular weight ranging between 20,000 and 350,000 g/mol, whereby the wt. % of the components a) to c) amounts to 100 wt. %, and to moulded bodies that can be obtained from said materials.
摘要:
Composition containing, based in each case on its total weight, A) 50.0% by weight to 99.5% by weight of at least one (meth)acrylate (co)polymer and B) 0.5% by weight to 50.0% by weight of at least one copolymer obtainable by polymerization of a monomer mixture comprising i. 70% by weight to 92% by weight of a vinylaromatic monomer and ii. 8% by weight to 30% by weight of acrylonitrile or methacrylonitrile or mixtures thereof and iii. 0% by weight to 22% by weight of at least one further monomer, the composition having a haze according to ASTM D1003 of less than 2.0% at 23° C. and a haze according to ASTM D1003 of less than 4.0% at 40° C. and the composition containing at least one (meth)acrylate (co)polymer a) having a solution viscosity in chloroform at 25° C. (ISO 1628—part 6) of greater than 55 ml/g. The moldings obtainable from the composition are distinguished in particular by improved stress cracking resistance and are suitable in particular for coverings, finishes or films.
摘要:
The invention relates to a moulding composition and to the mouldings which can be produced therefrom. Due to their good resistance in the hot water cycle test and in the hot-water/isopropanol test, the plastics mouldings have particularly good suitability for the production of sanitary components.
摘要:
The invention relates to a shaping tool for the injection molding or injection compression of information carrier disc blanks (11) made of polymethacrylate plastic which is suited as a component of an injection molding or injection compression machine. The shaping tool is comprised of two mold parts (1, 2), whereby one mold part (1) contains a bottom part (8) of a mold with the information data and, together with the second mold part (2), forms a cavity for the one information carrier blank and one sprue bush (4) for a sprue piece (5) in the tool having a concentrically positioned feed orifice (6). In addition, the tool comprises a impact cylinder (9) for shearing the sprue piece (5) and has an ejector pin (10). The invention is characterized in that the injection gap (SP) between the feed orifice (6) of the sprue piece (5) and the information carrier disc blank (11) is less than 0.3 mm. In addition, the cutting gap (SN) between the edge of the impact cylinder (9) and the information carrier disc blank (11) is less than 0.2 mm.