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.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

The present invention provides a polyarylene sulfide (PAS) production device which suppresses the accumulation of deposits on a baffle (baffle board) or the like disposed inside a reaction vessel via a baffle support for the purpose of enhanced stirring efficiency or the like, thereby contributing to enhanced production efficiency, reduced cost of removing accumulation, and enhanced quality of the PAS product.

The PAS production device of the present invention is a PAS production device provided with a reaction vessel equipped with one or a plurality of baffles; each baffle being supported by one or a plurality of baffle supports provided in a protruding manner on an inside wall of the reaction vessel; and at least one of the baffle supports having one or a plurality of openings preferably passing through the baffle support in the vertical direction.

Provided are a heat-resistant synthetic resin microporous film that has both good heat resistance and good mechanical strength and exhibits a suppressed decrease in mechanical strength over time, and a method for producing the heat-resistant synthetic resin microporous film. The heat-resistant synthetic resin microporous film of the present invention includes a synthetic resin microporous film, and a coating layer formed on at least part of the surface of the synthetic resin microporous film and containing a polymer of a polymerizable compound having two or more radically polymerizable functional groups per molecule. The maximum thermal shrinkage rate of the heat-resistant synthetic resin microporous film when heated from 25° C. to 180° C. at a temperature rising rate of 5° C./min is 15% or less. The piercing strength thereof is 0.6 N or more. The rate of retention of the piercing strength after heating at 70° C. for 168 hours is 85% or more.

The present invention is directed to a coating composition or paint comprising a multistage latex with at least first and second stages, wherein the composition or paint is substantially free of volatile organic compounds (VOC) and capable of film formation even in the absence of coalescent agents. The base paint formulation is capable of being tinted at a point-of-sale (i.e. in-store) using a colorant composition of a type and quantity required to produce a paint of desired color and finish. The paints, show improved block resistance, scrub resistance and tack resistance. Rheological techniques as described herein may be used to determine tack resistance, print resistance, and other performance characteristics.

Disclosed are nitrile-vinylidene substituted aromatic polymers which include less than about 250 ppm of vinylidene substituted aromatic monomer. Also disclosed is a method of minimizing nitrile migration in nitrile-vinylidene substituted aromatic polymers where the amount of residual vinylidene substituted aromatic monomer in the nitrile-vinylidene substituted aromatic polymer is reduced. Also disclosed is a method of making nitrile-vinylidene substituted aromatic polymers which includes less than about 250 ppm of styrene monomer.

Disclosed are nitrile-vinylidene substituted aromatic polymers which include less than about 250 ppm of vinylidene substituted aromatic monomer. Also disclosed is a method of minimizing nitrile migration in nitrile-vinylidene substituted aromatic polymers where the amount of residual vinylidene substituted aromatic monomer in the nitrile-vinylidene substituted aromatic polymer is reduced. Also disclosed is a method of making nitrile-vinylidene substituted aromatic polymers which includes less than about 250 ppm of styrene monomer.

A terpolymer containing propylene, ethylene and an alpha olefins of formula CH2=CHZ wherein Z is an hydrocarbon group having from 2 to 10 carbon atoms wherein: (i) the content of ethylene derived units ranges from 0.5 wt % to 5.0 wt %; (ii) the content of alpha olefin derived units ranges from 1.0 wt % to 5.0 wt %; (iii) the area of the DSC curve after the peak of the melting point (Tm) represents more than 22%; of the total area of the DSC curve; (iv) the polydispersity index (PI) ranges from 2.0 to 7.0.

A terpolymer containing propylene, ethylene and an alpha olefins of formula CH2=CHZ wherein Z is an hydrocarbon group having from 2 to 10 carbon atoms wherein: (i) the content of ethylene derived units ranges from 0.5 wt % to 5.0 wt %; (ii) the content of alpha olefin derived units ranges from 1.0 wt % to 5.0 wt %; (iii) the area of the DSC curve after the peak of the melting point (Tm) represents more than 22%; of the total area of the DSC curve; (iv) the polydispersity index (PI) ranges from 2.0 to 7.0.