Teijin Limited

Teijin Fibers Limited

Minoru Nakashima

Kazuhiro Sato

Kenichi Ishihara

Masanori Miyamoto

Kouji Mukai

Kazumasa Mizuno

Minoru Suzuki

Kenji Ishida

Hiroki Nagano

Tetsuya Chikatsune

Takuo Nakao

Hideo Hasegawa

Kozo Toida

Hitoshi Nagasawa

Taizo Mori

The purpose of the present invention is to provide a method for collecting effective components from polyester fiber waste containing polyalkylene telephthalate as the main component, more specifically to provide a method for separating and removing foreign matters (mainly cotton) contained in polyester fiber waste. The purpose of the invention can be achieved by a method for separating and removing foreign matters from polyester waste, which includes throwing polyester fiber waste that contains polyalkylene telephthalate as the main component and foreign matters other than the polyalkylene telephthalate into a depolymerization reaction tank, subjecting a part or all of the polyester fiber to a depolymerization reaction with alkylene glycol to give a depolymerization reaction liquid, and then continuously or intermittently feeding the liquid to a foreign matter-separating and removing apparatus having specified characteristics.

Method for separating and removing foreign matters from polyester fiber waste

A problem of the invention is to provide a method which targets on polyethylene terephthalate-made bottle scraps composed mainly of polyethylene and/or polypropylene, polystyrene and a polyester and which is able to treat continuously a large amount of the polyester component with a high purity and sort and recover it in a high recovery. The problem of the invention can be solved by a separation method of waste plastics, which is characterized by forming previously a crushed plastic into a water slurry, feeding the water slurry in a fixed rate range such that a swirling flow is generated within a cylindrical tank and that water rises in a fixed rate range and recovering a polyester with a high specific gravity as a precipitated component within the cylindrical tank and a plastic with a low specific gravity as an overflow component from the top of the cylindrical tank, respectively.

Method for sorting mixed plastic

To establish an efficient and economical useful component recovery method capable of recovering high purity useful components from a dyed polyester fiber. A method for recovering useful components from a dyed polyester fiber, includes a dye extraction step, a solid liquid separation step, a depolymerization reaction step, an ester interchange reaction step, and a useful component separation step, for recovering useful components from the dyed polyester fiber, wherein the dye extraction step includes a step of extracting and removing a dye at the glass transition temperature of the polyester or higher and at 220&#xb0; C. or less with a xylene extracting solvent and an alkylene glycol extracting solvent in combination.

Method for recovering useful components from dyed polyester fiber

A through process comprising depolymerization reaction of used PET bottles with EG, recovering DMT by ester interchange reaction with MeOH, obtaining terephthalic acid by hydrolysis of the recovered DMT, and manufacturing a PET polymer which can be used for manufacturing PET bottles again by using the terephthalic acid.

Method for recycling pet bottle

A dimethyl terephthalate composition includes 0.001 to 200 ppm of methyl 4-(1,3-dioxolan-2-yl)benzoate and 0 to 1 ppm of dimethyl hydroxyterephthalate contained in dimethyl terephthalate, and exhibits improved properties as a material for producing polyester.

Dimethyl terephthalate composition and process for producing the same

For separation and recovery of dimethyl terephthalate (DMT) and ethyiene glycol (EG) from polyester waste containing foreign materials, the polyester waste is treated in EG containing a polyester depolymerization catalyst, a solid foreign material fraction floated on the surface of the resultant reaction solution is removed and the residual solid foreign material fraction is removed from the remaining solution fraction. The remaining solution fraction is distilled and concentrated and the distilled EG is recovered. A transesterification reaction catalyst and methanol are mixed into the distillation residue. The resultant reaction mixture is recrystallized and subjected to centrifugal separation to separate the reaction mixture into the DMT cake and a mixture solution, and then the cake is distilled whereby high-purity DMT is recovered. The residual mixture solution is subjected to distillation treatment for recovery of the methanol, and the distillation residue is distilled to recover EG.

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Matsuyama, Japan

Minoru Nakashima