Abstract: A clamping jaw for a chuck includes a jaw body on which there is formed at least one jaw step having a step head, which has a sensor on its end face, for holding a clamping insert which is formed from a base leg and two fastening legs projecting from the base leg. On each of the opposite longitudinal sides of the step head there is formed a threaded bore for receiving a fastening screw whose screw head is received in a through-opening which is formed in the fastening leg of the clamping insert that is assigned to the longitudinal side, wherein, on each side, the longitudinal axes of the threaded bore and of the through-opening assigned thereto have an offset when the base leg bears against the end face. Also, a chuck has a chuck body, in which such clamping jaws are arranged in uniformly-distributed radial jaw guides.

Abstract: A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

Abstract: Methacrolein is prepared in a continuous process by a Mannich condensation reaction of formaldehyde with propanal. A methacrolein polymerization inhibitor is introduced during the production process and a part thereof is recycled back into the reactor where the Mannich condensation reaction is carried out.

Abstract: A process can be used for producing methacrylic acid or a methacrylic acid ester. The process involves producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to obtain methacrylic acid or methacrylic acid ester.

Abstract: A process can be used for manufacturing an acrylic copolymer having increased heat resistance, high transparency, and improved adhesion to metal surfaces. The process involves polymerizing a monomer mixture, optional heating of the copolymer mixture, and removing volatile components from the copolymer mixture by degassing. Moulding compositions containing this copolymer are highly suitable for manufacturing optical elements for optoelectronic devices containing acrylic and metallic or ceramic parts.

Abstract: A continuous process can be used for preparing methacrylic acid by catalytic hydrolysis of methyl methacrylate that has been prepared proceeding from C-2, C-3, or C-4 raw materials. In this process, methyl methacrylate of high purity is reacted with water in the presence of a Brønsted catalyst to give a reaction mixture containing the reactants and products and worked up in a distillation column. In the distillation column, a condensate containing an azeotrope of MMA with methanol is produced at the top, a vapour condensate containing methacrylic acid of high purity is produced in the middle part of the column, and a substance mixture containing high-boiling by-products and a small amount of methacrylic acid is obtained in the bottom of the column.

Abstract: An extruded foil may include at least one layer in which platelet-shaped filler particles are uniformly distributed in a polymer matrix comprising at least one fluoropolymer and at least one further layer. The foil may have a particularly high TSR, a high weathering resistance, and excellent mechanical properties. Therefore, the foil may be highly suitable for surface-protection of materials such as polyvinyl chloride (PVC) and for use in high-pressure laminates (HPLs).

Abstract: A device can be used for the degassing of a two-component multiphase polymer-monomer material. A corresponding degassing extruder contains the degassing device. The device for degassing contains at least one nozzle part having a convergent geometry, at least one constant part, and at least one diffusor part having a divergent geometry. The diffusor part contains at least three zones each having a divergent geometry, and the opening angles of the zones are specifically adapted in order to improve the separation of components of the polymer material. A process for degassing a polymer material uses the degassing device.

Abstract: An improved process for synthesizing methacrylic acid and/or alkyl methacrylates, in particular methyl methacrylate (MMA), involves reacting acetone and hydrogen cyanide in the presence of an alkaline catalyst in a first reaction stage such that a first reaction mixture containing acetone cyanohydrin (ACH) is obtained. The process then involves working up the first reaction mixture containing acetone cyanohydrin (ACH), reacting acetone cyanohydrin (ACH) and sulfuric acid in a second reaction stage (amidation), and heating the second reaction mixture in a third reaction stage (conversion), such that methacrylamide (MAA) is obtained. The process further involves hydrolyzing or esterifying methacrylamide (MAA) with water and, optionally, alcohol, preferably water and optionally methanol, in a fourth reaction stage such that methacrylic acid or alkyl methacrylate is formed. The sulfuric acid used has a concentration of 98.0 wt % to 100.0 wt %.

Abstract: A process for producing methacrylic acid or a methacrylic acid ester including, producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to methacrylic acid or a methacrylic acid ester.

Abstract: A novel process can be used for a heterogeneously catalysed oxidation reaction, in the presence of a pulverulent noble metal-containing catalyst, where (meth)acrolein, an alkyl alcohol, in particular methanol, and an oxygen-containing gas are converted to an alkyl (meth)acrylate, in particular methyl (meth)acrylate. A corresponding reactor suitable for performing the reaction is also useful. The process allows for an effective retention of the particulate catalyst and the continuous discharge of fines fractions of the catalyst powder which are present, particularly in a fresh catalyst batch as a consequence of its preparation. Such fines fractions may also be produced by abrasion during the reaction. The process allows for effective recycling, recovery, and utilization of these discharged catalyst fractions.

Abstract: An improved process for synthesizing alkyl methacrylates, in particular methyl methacrylate (MMA), involves reacting acetone cyanohydrin (ACH) and sulfuric acid in a first reaction stage (amidation). The process then involves heating the first reaction mixture in a second reaction stage (conversion) such that methacrylamide (MAA) is obtained; and then esterifying methacrylamide (MAA) with alcohol and water, preferably methanol and water, in a third reaction stage such that alkyl methacrylate is formed. The sulfuric acid used has a concentration of 98.0 wt % to 100.0 wt %. A subsequent working up of the third reaction mixture involves least two distillations in which the byproducts methacrylonitrile (MeAN) and acetone are obtained as an aqueous heteroazeotrope at least in part in the top fraction. At least some of the aqueous heteroazeotrope is removed from the process and at least partially reintroduced into the third reaction stage.

Abstract: A process for preparing methyl methacrylate (MMA) and/or methacrylic acid (MAS) having improved yield, involves amidation, conversion, and hydrolysis/esterification. Especially high yields are obtained during the amidation and in the subsequent so-called conversion.

Abstract: A transparent acrylic-based polymer composition has an increased resistance to alcohols, oils and fats. The polymer composition contains: (A) a copolymer of alkyl(meth)acrylates, aromatic vinyl monomer and unsaturated carboxylic acid anhydride; (B) a copolymer containing aromatic vinyl monomer and a vinyl cyanide monomer; and (C) a particulate core-shell type graft copolymer containing a butadiene-based core as a rubbery phase and a copolymer containing alkyl(meth)acrylates and, optionally, aromatic vinyl monomer as a hard phase. The components A and B form a polymer matrix and the particulate core-shell type graft copolymer C is dispersed in said polymer matrix.

Abstract: A process can be used for producing optical molding materials on the basis of methyl methacrylate (MMA). The MMA produced by an optimized method and the molding materials feature in particular a very low yellowness index. This MMA has been produced by direct oxidative esterification of methacrolein. An optimized workup of the reactor output from the oxidative esterification of methacrolein can be used for removing particularly discoloring byproducts. This process moreover has the advantage that fewer demands are placed on plant apparatus configuration.

Abstract: A copolymer has increased heat resistance, high transparency, and low haze values. Moulding compositions can contain this copolymer and a process can be used for the manufacturing this copolymer. The moulding compositions are highly suitable for the manufacturing of optical elements used in various optical devices including primary optics, secondary optics, tertiary optics, as well as light guides.

Abstract: A novel process can be used for purifying methyl methacrylate (MMA) contaminated with low-boiling components by distillation, where the process involves producing MMA by oxidative esterification, and a crude product containing methyl propionate (MP), methyl isobutyrate (MIB), and methacrolein (MAL) as low-boiling components. The process is compatible with MMA produced from C2-based methacrolein containing the low-boiling components specified.

Abstract: A novel reaction resin formulation having a significantly improved properties profile contains crosslinkers, monomers, urethane methacrylates, prepolymers, optional further auxiliaries, and a curing system containing permaleinates and a tertiary organic phosphite. The reaction resin formulation is useful for marking driving surfaces or coating surfaces. The reaction resins, above all based on a novel curing system, show an improved combination of higher long-term storage stability, improved toxicological profile, reduced curing time, a low yellowing tendency and a better colour fastness.

Abstract: A new method can be used for producing suitable improved carrier materials as a base material for catalysts for carrying out a direct oxidative esterification. In general, the catalyst is used to convert aldehydes with alcohols in the presence of oxygenic gases directly to the corresponding ester, for example, where (meth)acrolein can be converted to methyl(meth)acrylate. The catalysts used are characterized in particular by high mechanical and chemical stability as well as by good catalytic performance even over very long periods of time. This applies in particular to an improvement of catalyst service life, activity and selectivity in comparison to other catalysts.

Abstract: A novel process can be used for preparing methacrylates, such as methacrylic acid and/or alkyl methacrylates, especially MMA. The process allows for prolonging of the catalyst service life and an increase in efficiency of the methacrylate preparation based on C2 or C4 raw materials, especially when proceeding from isobutylene or tort-butanol or ethylene as raw material. The process allows for performance for longer periods without disruption, with constant or even increased activities and selectivities. This gives rise to the possibility of performing such processes in a very simple, economically viable, and environmentally benign manner. In addition, it has been possible to minimize known safety risks that emanate from the methacrolein intermediate.