Abstract: This invention relates to polyethylene isophthalate (PEI) and copolymers thereof having low cyclic dimer content and process for making same. The invention provides a process for making PEI using protonic acid catalysts which result in a polymer having lower amounts of ring dimer of ethylene isophthalate than has heretofore been known. Strong protonic acids such as sulfuric or phosphoric are utilized as polymerization catalysts to thereby lower the amount of cyclic dimerization which occurs during the polymerization process. Polymers so produced are of a high purity and have reduced manufacturing costs due both to a smaller amount of material being lost as cyclic dimer and because of lower processing costs associated with cleaning cyclic dimer from the processing equipment.

Abstract: A high clarity, low haze polyester having improved heat-up rates contains very small amounts of an infrared absorbent material therein such as carbon black. Such polyesters are used in preforms as for making trays, etc., and especially in molding operations such as in the blow molding of beverage bottles.

Abstract: Polyisophthalates, for example, poly(ethylene isophthalate), or copolymers thereof, have low glass transition temperatures, even lower than poly (ethylene terephthalate). Unexpectedly, such polyisophthalates have very good barrier properties with regard to oxygen and carbon dioxide penetration. The polyisophthalates can be utilized as packaging materials, for example as films or containers such as bottles for beverages such as intoxicating beverages such as beer, and the like.

Abstract: This invention relates to a method of improving the brightness and color of a polyester resin and reducing the acetaldehyde content by passing the resin through molecular sieves at a temperature of from 230.degree. C. to about 300.degree. C.

Abstract: A process for reducing the level of cyclopentadiene present in a hydrocarbon stream containing isoprene and cyclopentadiene which involves contacting the stream with a base wherein said base is selected from the group consisting of potassium hydroxide, sodium hydroxide and potassium fluoride. The base is situated on activated carbon carrier.

Abstract: A process for reducing the level of cyclopentadiene present in a hydrocarbon stream containing isoprene and cyclopentadiene which involves contacting the stream with an alkali metal hydroxide wherein the reaction product is an insoluble salt of CPD.