Mitsui Petrochemical Industries, Ltd.

Shigemi Shiraki

Masayuki Sakai

Kenichi Mizuno

Yasuhiro Tanaka

Toshihiro Sagane

Mikio Hashimoto

Hiroji Niimi

Ryoichi Yamamoto

Tadao Yatsu

Shuji Minami

Masayuki Okabe

Hideaki Yamaguchi

Shikiho Itaya

Kenji Wakatsuru

Takenori Nagaoka

Ryosuke Tomita

Yukimasa Shigemura

Teruo Itoh

Saiji Nakano

Takehiko Kawate

In accordance with the present invention, there are provided cycloolefin random copolymers composed of ethylene and cycloolefin and containing substantially no polyethylene, and processes for preparing the same. Optical disc substrates prepared from the above-mentioned copolymers are excellent in transparency and also capable of minimizing the occurence of errors in reading of the discs due to quality of the substrates used therefor.

Cycloolefin random copolymer and process for preparing same

According to the present invention, a process which comprises bringing polyethylene terephthalate having an intrinsic viscosity of at least 0.50 dl/g and a density of 1.38 g/cm.sup.3 or more into contact with water is provided. In the water-treated polyethylene terephthalate obtained in the present invention, amounts of oligomers and acetaldehyde formed at the time of molding said polyethylene terephthalate into molded articles are small, and the contamination of the mold therewith is difficult to occur and further the contents of said molded articles does not change in flavor and fragrance.

Process for treatment of polyethylene terephthalate, polyethylene

Polyethylene terephthalates of the present invention are excellent in mechanical strength, heat resistance and transparency, and therefore blow molded containers molded from the present polyethylene terephthalate are excellent in high temperature filling properties when they are filled with juice, refrigerant beverage, carbonated beverage, seasonings, etc. Furthermore, the blow molded containers prepared from the present polyethylene terephthalates have such characteristic features that they are free from thermal deformation at the time when they are subjected to high temperature filling, they are readily subjected to sterilization treatment and hence excellent in high speed filling properties.

Polyethylene terephthalate and uses thereof

According to the present invention, a process which comprises bringing polyethylene terephthalate having an intrinsic viscosity of at least 0.50 dl/g and a density of 1.38 g/cm.sup.3 or more into contact with water is provided. In the water-treated polyethylene terephthalate obtained in the present invention, amounts of oligomers and acetaldehyde formed at the time of molding said polyethylene terephthalate into molded articles are small, and the contamination of the mold therewith is difficult to occur and further the contents of said molded articles does not change in flavour and fragrance.

A process for the production of high purity terephthalic acid, by subjecting a crude terephthalic acid product, resulting from the oxidation of a paradialkylbenzene and containing a 4-carboxybenzaldehyde and other impurities at a relatively high level, to an efficient purification with high yield of terephthalic acid. This process comprises subjecting a high temperature aqueous solution of the crude terephthalic acid product to (A) an oxidation treatment with an oxygen-containing gas while feeding oxygen at a feed rate in the range of 0.4-10 moles per mole of the 4-carboxylbenzaldehyde contained in the crude terephthalic acid and then to (B) a treatment with hydrogen.

Process for the production of high purity terephthalic acid

A process for the production of aromatic carboxylic acid in a continuous manner by oxidizing an alkyl aromatic compound in the liquid phase with an oxygen-containing gas in the presence of heavy metal compound(s) and/or bromine-containing compound, which process is characterized by that a part of the reaction gas delivered from the reactor and freed from the condensing components is recirculated by returning it to the reactor at a portion within the gas region. Said process permits to produce aromatic carboxylic acids of high quality, while eliminating the troubles due to foaming occurring on the liquid surface in the reactor.

Process for the production of aromatic carboxylic acids

A tubular polymerization reactor comprising a feed opening for a polymerizable material at one end portion, a withdrawal opening for the resultant polymer at the other end portion, a tubular reaction space within the reactor extending from said feed opening to said withdrawal opening, and a rotary conveying member disposed within the reaction space and extending therealong with some clearance from the inner wall surface of the polymerization reactor; characterized in that

Tubular polymerization reactor, and process for polymerization

In an apparatus for oxidizing an alkyl-substituted aromatic compound in the liquid phase with a molecular oxygen-containing gas in a lower aliphatic carboxylic acid solvent in the presence of an oxidation catalyst, said apparatus comprising a reaction vessel, a gas exhaust port at the top of the vessel, an inlet at the bottom of the vessel for feeding said molecular oxygen-containing gas, an inlet for feeding said solvent, an inlet for feeding said catalyst, an inlet for feeding said alkyl-substituted aromatic compound, an outlet for withdrawing the oxidation reaction product, and an agitator within the vessel, said agitator consisting of a rotating shaft provided along the axial direction of the vessel and a plurality of stages of agitating blades secured to said rotating shaft at spaced intervals; the improvement wherein at least one stage of agitating blades consists of comb-like flat blades each of which is composed of a plurality of comb tooth-like pieces aligned at spaced intervals.

Apparatus for the continuous liquid-phase catalytic oxidation of

Improved process for producing terephthalic acid by liquid-phase catalytic oxidation of p-xylene with oxygen at a temperature of at least about 160.degree. C. and a pressure of at least about 5 kg/cm.sup.2 G under specific recycling condition of the mother liquor, which comprises

Process for producing terephthalic acid

A process for treatment by a liquid cyclone for the production of a suspension of terephthalic acid having a reduced impurity content which comprises supplying a fresh and hot lower aliphatic carboxylic acid solvent to a liquid-phase catalytic oxidation product of a p-alkylbenzene or a hot, impurity-containing suspension of terephthalic acid particles in a mother liquor containing a lower aliphatic carboxylic acid solvent, feeding the resulting mixture into a liquid cyclone, treating it in the cyclone at an elevated temperature, withdrawing an impurity-containing liquid composed mainly of said mother liquor from a withdrawal opening provided near one end of the cyclone, and withdrawing a suspension of terephthalic acid particles in a lower aliphatic carboxylic acid solvent consisting mainly of said fresh solvent from a withdrawal opening provided near the other end of the cyclone; wherein a fresh lower aliphatic carboxylic acid solvent is additionally supplied into the cyclone through an opening provided between a position apart from the suspension withdrawal opening of the liquid cyclone toward its mixture-feeding opening by a distance corresponding to about two-thirds of the distance (h.sub.o) from the mixture-feeding opening to the suspension withdrawal opening and a position apart from the suspension withdrawal opening toward its mixture feeding opening by a distance corresponding to about one-tenth of the distance (h.sub.o).

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Kuga, Japan

Shigemi Shiraki