摘要:
The invention relates to a device and method for producing thick-walled plastic molded parts by injection molding or embossing. The device comprises a mold for injection molding or embossing, having a cavity, and is characterized in that the mold comprises a wall region adjacent to the cavity, and a body removed from the cavity and adjacent to the wall region near the cavity, wherein the body of the mold is designed for a temperature T1 and the wall region is designed for a temperature T2 different from the temperature T1. According to the method, the temperature T2 of the wall region of the mold near the cavity is brought to and held at a value greater than the Vicat temperature Tv of the plastic molding mass before and/or during the injection process, wherein the temperature T2 is greater than the temperature T1 of the mold body, and the temperature T2 of the wall region near the cavity is brought to a temperature below the Vicat temperature Tv of the plastic molding mass during the solidification of the plastic molding mass. The result is thick-walled molded plastic parts, such as optical lenses and the like, having reduced shrinkage sites.
摘要:
The invention relates to an injection moulding method for the production of a complex, high optical quality light-diffusing moulded item. The moulding material used comprises a matrix made of polymethyl(meth)acrylate and spherical plastic particles whose particle size ranges from 1-24 μm and the concentration thereof ranges from 0.05-30 wt.-% in relation to the weight of the polymethyl(meth)acrylate. The spherical particles exhibit a refractive index differential in relation to the polymethyl(meth)acrylate matrix of 0.01 0.2.
摘要:
The invention relates to an injection molding method for the production of a complex, high optical quality light-diffusing molded item. The molding material used comprises a matrix made of polymethyl(meth)acrylate and spherical plastic particles whose particle size ranges from 1-24 μm and the concentration thereof ranges from 0.05-30 wt.-% in relation to the weight of the polymethyl(meth)acrylate. The spherical particles exhibit a refractive index differential in relation to the polymethyl(meth)acrylate matrix of 0.01 0.2.
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.
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).