A method of processing one or more streams in a phthalate-containing polymer recycling system, the method comprising receiving an extract stream and a raffinat4e stream from a liquid chromatography unit, which is part of the polymer recycling system, wherein the extract stream comprises a bis(hydroxyalkyl) phthalate monomer, C.sub.2-5 alkylene diol, and solvent, and wherein the raffinate stream comprises first impurities, C.sub.2-5 alkylene diol, and solvent; vacuum distilling the extract stream to produce a first solvent stream and a monomer and diol stream comprising the bis(hydroxyalkyl) phthalate monomer and C.sub.2-5 alkylene diol; subjecting the monomer and diol stream to steam separation to produce a monomer stream comprising the bis(hydroxyalkyl) phthalate monomer and water, and a diol stream comprising C.sub.2-5 alkylene diol and water; and vacuum distilling the raffinate stream to produce a second solvent stream and a first impurities stream comprising first impurities and C.sub.2-5 alkylene diol.

A process and a system for continuously depolymerizing plastic is disclosed. The system may comprise a mixer for producing a heterogeneous reaction mixture comprising plastic particles and a solvent, a pump for transmitting the reaction mixture at a particle speed sufficient to maintain the plastic particles in suspension in the solvent, a heating apparatus for heating the reaction mixture to its reaction temperature, a hold tube for maintaining the reaction mixture at or above the reaction temperature to facilitate conversion into a homogeneous reaction solution, and a settling tank to allow a solid reaction product to precipitate from the homogeneous reaction solution once cooled.

A process and a system for continuously depolymerizing plastic is disclosed. The system may comprise a mixer for producing a heterogeneous reaction mixture comprising plastic particles and a solvent, a pump for transmitting the reaction mixture at a particle speed sufficient to maintain the plastic particles in suspension in the solvent, a heating apparatus for heating the reaction mixture to its reaction temperature, a hold tube for maintaining the reaction mixture at or above the reaction temperature to facilitate conversion into a homogeneous reaction solution, and a settling tank to allow a solid reaction product to precipitate from the homogeneous reaction solution once cooled.

A method for recycling polyester/polyurethane is provided. The method comprises adding additives containing hydroxyl or/and amino groups to polyester/polyurethane waste and performing transesterification or transcarbamoylation at 80-180° C. to form recycled new materials with different structures including polyester, polyurethane, polyamide, and polyurea.

A method for recycling polyester/polyurethane is provided. The method comprises adding additives containing hydroxyl or/and amino groups to polyester/polyurethane waste and performing transesterification or transcarbamoylation at 80-180° C. to form recycled new materials with different structures including polyester, polyurethane, polyamide, and polyurea.

A treatment plant (1) transforms a material containing PET in flakes (2) into a depolymerized material (3). The plant includes a first treatment unit (10) having a first material inlet (11) for feeding the material containing PET in flakes (2), a first unit outlet (12) for outputting a semi-finished material of molten PET (4). A first unit path (14) extends between the first unit inlet (11) and the first unit outlet (12). A compression and mixing device (20) is arranged along the first unit path (14). An injection device (30) for injecting a treatment liquid (31) leads to an injection point (32) along the first unit path (14).

A treatment plant (1) transforms a material containing PET in flakes (2) into a depolymerized material (3). The plant includes a first treatment unit (10) having a first material inlet (11) for feeding the material containing PET in flakes (2), a first unit outlet (12) for outputting a semi-finished material of molten PET (4). A first unit path (14) extends between the first unit inlet (11) and the first unit outlet (12). A compression and mixing device (20) is arranged along the first unit path (14). An injection device (30) for injecting a treatment liquid (31) leads to an injection point (32) along the first unit path (14).

Disclosed herein are embodiments of a method for making recyclable polymers and a method for decomposing the polymers back to the monomers which can then be reused. The polymer are stable to aqueous and/or acid conditions and may have a formula II

##STR00001##

The method to decompose the polymer back to the monomers may comprise heating the polymer in a protic organic solvent.

Disclosed herein are embodiments of a method for making recyclable polymers and a method for decomposing the polymers back to the monomers which can then be reused. The polymer are stable to aqueous and/or acid conditions and may have a formula II

##STR00001##

The method to decompose the polymer back to the monomers may comprise heating the polymer in a protic organic solvent.

A biaxially oriented polyester film having the following physical property is provided: when cooled from the molten state at a cooling rate of 20° C/min, an observed recrystallization temperature is 175° C-200° C. The biaxially oriented polyester film is formed by a thick sheet before bidirectional stretching that is melted and extruded by an extruder and then cooled and formed on a casting roll. The thick sheet before stretching having the following physical property as analyzed by differential scanning calorimetry: a crystallization rate is less than 10%.