Arco Polymers, Inc.

Atlantic Richfield Company

Harold A Wright

Alvin R Ingram

Adolph V DiGiulio

Walter O Pillar

Kenneth D Thom

The production of polymer beads from vinyl aromatic monomers, using an inorganic phosphate aqueous suspension polymerization process is effected with the addition of 0.0001 to 0.004 percent by weight of a polystyrenesulfonate with the production of beads having a narrow bead size distribution. In addition to the improved bead size distribution, large beads can be produced which retain their sphericity.

Process for bead size control in vinyl aromatic suspension

Styrenic polymer expandable beads that are useful in forming heat-resistant foamed articles are prepared by forming an aqueous suspension of initial styrenic polymer beads and adding thereto a portion of a comonomer solution of styrenic monomer and methacrylic acid, which solution also contains a polymerization regulator, forming an emulsion of catalyst, monomer solution and polyvinyl alcohol suspending agent, adding portions of the emulsion to the suspension and then adding the remainder of the comonomer solution to the suspension, and the suspension with added monomers is heated to copolymerize the styrenic monomer and methacrylic acid about the initial beads and form a coating about the beads.

Process for producing coated styrenic polymer beads for heat resistant

Styrenic polymer beads of a preferred size are produced from styrenic polymer beads of a smaller size by forming an aqueous suspension of the styrenic polymer beads and adding thereto, under polymerization conditions, an aqueous emulsion formed by admixing styrenic monomer and a catalyst therefor with water containing a nonionic surfactant that is an ethylene oxide condensate of an alkylphenol, which contains at least fifty moles of ethylene oxide per mole of alkylphenol. The beads of preferred size are formed without formation of fine styrenic polymer particles and without significant amounts of clusters of beads.

Process for producing styrenic polymer beads of preferred bead size

The production of polymer beads by a suspension polymerization process in which a vinyl aromatic monomer having a free-radical generating catalyst dissolved therein is suspended in an aqueous medium with the aid of from 0.1 to 2.0 percent by weight, based on monomer, of a finely divided phosphate suspending agent in the presence of a modifier and heated to cause the monomer to polymerize into polymer beads is improved by the addition to the suspension of at least about 0.01 percent by weight based on monomer of an adjunct modifier, glutamic acid. Although the process of the invention is especially applicable in the preparation of large polymer beads, the glutamic acid also makes it possible to prepare the smaller polymer beads having narrow particle size distribution, also.

Bead size distribution in the suspension polymerization of vinyl

The production of polymer beads by a suspension polymerization process in which a vinyl aromatic monomer having a free-radical generating catalyst dissolved therein is suspended in an aqueous medium with the aid of from 0.1 to 2.0 percent by weight, based on monomer, of a finely divided phosphate suspending agent in the presence of a modifier and heated to cause the monomer to polymerize into polymer beads is improved by the addition to the suspension of at least about 0.01 percent by weight based on monomer of an adjunct modifier, such as certain aminoalkanecarboxylic acids and N-substituted derivatives thereof. The process of the invention is especially applicable in the preparation of large polymer beads.

The production of polymer beads by a suspension polymerization process in which a vinyl aromatic monomer having a free-radical generating catalyst dissolved therein is suspended in an aqueous medium with the aid of from 0.1 to 2.0 percent by weight, based on monomer, of a finely divided phosphate suspending agent in the presence of a modifier and heated to cause the monomer to polymerize into polymer beads is improved by the addition to the suspension of at least about 0.02 percent by weight based on monomer of certain aminoalkanesulfonic acids and N-substituted derivatives thereof. The process of the invention is especially applicable in the preparation of large polymer beads.

Attempts to prepare polystyrene by peroxide-initiated suspension polymerization at 125.degree. C resulted in polymer having narrower molecular weight distribution than desired. The problem has been solved by copolymerizing the styrene with from 0.05 to 0.35 weight per cent, based on styrene, of a modifying comonomer consisting of a non-conjugated diolefinic compound having one very reactive olefinic group and one less reactive olefinic group such as, for example, allyl methacrylate.

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Murrysville, PA, United States of America

Harold A Wright