JPH09302076A - Polyethylene terephthalate article and method for separating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recycle waste polyethylene articles by making it possible to separately collect only fine particles of polyethylene terephthalate simply at good efficiency by means of an electromagnet from a mixture comprising fine particles obtained by grinding waste polyethylene terephthalate bottles and also by grinding articles made of other plastics. SOLUTION: A terephthalic acid/ethylene glycol condensation polymer is mixed with 1wt.% magnetic ally sensitive substance comprising a metallic iron powder having a mean particle size of 0.01mm. The obtained mixture is formed into chips and then molded into, e.g. PET bottles with a blow molding machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene terephthalate product which can be easily separated from other plastic products for recycling discarded polyethylene terephthalate products, and a method for separating the same.

[0002]

2. Description of the Related Art Polyethylene terephthalate is a linear polymer represented by the following chemical formula 1 and is widely used as a synthetic fiber, a film, a molded plastic product or the like. In particular, as a plastic molding, a so-called container for water, liquor, juice, seasonings, etc.
It is generally widely known as a PET bottle (hereinafter referred to as a PET bottle in the present specification). By the way, products such as PET bottles were discarded as waste when they were no longer needed.

Embedded image Conventionally, a method and a device for selecting a bottle having a relatively large specific gravity and a plastic bottle having a relatively small specific gravity by air blowing from a mixture of garbage bottles and various plastic bottles are known ( For example, JP-A-6-3
No. 43946, No. 5-269453). Moreover, empty PET bottles that have been discarded are collected and processed into recycled plastic materials for commercialization. For example, the recycled plastic materials are mixed with other petroleum-based fibers to produce high-quality fibers. It is also known to recycle clothes such as shirts, raincoats and the like, carpets and the like.

[0003]

However, even if PET products are recycled, some of the discarded plastics include vinyl chloride, polyethylene,
Since containers made of other materials such as polystyrene are mixed in, it is necessary to separate only the PET products from them, but at present, the separation work relies on manual work, and the work efficiency is poor. Therefore, the present invention particularly focuses on recycling of waste PET products discarded from homes, and collects polyethylene terephthalate separately and easily from the group of plastic products of various materials discarded from homes easily, reliably and efficiently. The polyethylene terephthalate collected separately can be used as a fiber, film or PET bottle, PET
It is an object of the present invention to provide a PET product that can be reused as a molded product and a method for separating the PET product.

[0004]

The PET product of the present invention comprises:
It is characterized by being molded from polyethylene terephthalate mixed with a magnetic sensitive material. The magnetic substance is mixed in the polymerization reaction step of the condensate polymer of terephthalic acid and ethylene glycol, or a chip of the condensate polymer of terephthalic acid and ethylene glycol is prepared and then mixed with this chip. These are subjected to bottle molding. Examples of the magnetic sensitive material include iron, manganese, nickel, or a compound thereof. Any one or a combination of two or more thereof is used, and examples thereof include manganese oxide, nickel silicate, and iron oxide. The method for separating PET products of the present invention comprises a step of crushing or crushing a polyethylene terephthalate product mixed with a magnetic sensitive material and a plastic product made of another material to obtain fine particles or flakes, and the fine particles or flakes. It comprises a step of adsorbing to a magnet and a step of collecting fine particles or flakes adsorbed by the magnet.

[0005]

The fine particles or flakes obtained by crushing or crushing a PET product mixed with a magnetic sensitive substance react with the magnetic force of a magnet and are adsorbed by the magnet, but fine particles of other plastic products not mixed with a magnetic sensitive substance. Objects or flakes do not react with the magnet and are not attracted to the magnet. PE obtained by carrying out the above separation method
The T recovery product is a mixture of PET which is crushed or not crushed and has various shapes, and it is a little difficult to utilize in the regeneration process. The PET recovery product is granulated by compressing while crushing. The recovered material that has been adopted and has undergone this granulation process is in the form of chips, and can be utilized as a raw material for fibers or plastic molded products in the recycling process.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) When terephthalic acid and ethylene glycol are continuously supplied to a known polyethylene terephthalate polymerization apparatus to carry out polymerization, a condensate polymer of terephthalic acid and ethylene glycol is charged with metallic iron powder having an average particle size of 0.01 mm. Mix 1% by weight. A condensate polymer of terephthalic acid and ethylene glycol mixed with the metal iron powder is supplied from a raw material inlet of a polyethylene terephthalate polymerization apparatus to cause a polymerization reaction in the apparatus, and the polymer is discharged from the outlet of the apparatus. A constant amount extrusion is performed using a gear pump.
At that time, a spinneret was attached to the discharge port of the gear pump, the polymer was spun into a gut shape with a diameter of about 1.5 mm, cooled and solidified with water, and the gut of polyethylene terephthalate with a diameter of about 1.5 mm was taken and cut. Using a machine, chips were cut to a length of about 1.5 mm. The chips were dried with a vacuum dryer. A PET bottle was molded by a blow molding machine using the dried chips thus obtained as a molding material. This process is schematically shown in FIG. In order to uniformly mix and disperse the magnetic sensitive material such as metallic iron powder in the condensate polymer of terephthalic acid and ethylene glycol, a known static mixer is used at the stage before the spinning pump during the polymer spinning of the above chips. It is desirable to install it in the polymer passage.

The PET bottle obtained by molding as described above is put into a crusher together with other polyethylene products, vinyl chloride products and polystyrene products and crushed. As shown in FIG. 2, which shows a separation and collection device, the fine particles 1 obtained by this crushing are a mixture of the PET fine particles 1a and other polyethylene and polystyrene fine particles 1b. The mixed fine granules 1 are dropped from the chute 2 onto the belt conveyor 3 and carried to the lower side of the belt conveyor type electromagnet 4. Then, the fine particles 1a mixed with the metal iron powder are the electromagnets 4
The fine particles 1b that are not adsorbed by the electromagnet 4 are collected in another collection box 7 by being scraped off by the scraper 5 and collected in the collection box 6. As a result of collecting and analyzing the fine particles 1a attached to the electromagnet 4 as described above, almost 100% of fine particles of polyethylene terephthalate could be separated and collected. Only 0.15% of polyethylene terephthalate was admitted from the remaining fine granules 1b.

Example 2 A polyethylene terephthalate chip (shape; diameter: about 1.5 mm, length: about 1.5 mm) was mixed with metal iron powder 1: iron oxide powder 1 at a mixing ratio of about 0. After mixing and stirring at a ratio of 0.8% by weight, a PET bottle was molded using a blow molding machine. This process is schematically shown in FIG.

A PET bottle molded in this way is
Individual pieces were collected and shredded with a crusher into flakes. This flake, polyethylene flakes, which is another plastic,
After mixing and stirring with vinyl chloride flakes and polystyrene flakes, a separation operation was performed by electromagnetic force. As a result of this test, almost 100% polyethylene terephthalate flakes could be collected separately.

[0010]

According to the present invention, a mixture of fine particles or flakes obtained by crushing a waste PET product and fine particles or flakes obtained by crushing a waste plastic product of another material is subjected to polyethylene terephthalate using an electromagnet. The fine particles or flakes can be easily and efficiently separated and collected. The separately collected polyethylene terephthalate can be recycled and used for various purposes, for example, as PET fibers for industrial use, clothing, PET bottles, films, etc., and effectively functions for reducing the amount of dust and recycling.

[Brief description of drawings]

FIG. 1 is a process diagram of Example 1.

FIG. 2 is a schematic diagram of a separation and collection device according to a first embodiment.

FIG. 3 is a process drawing of Example 2.

[Explanation of symbols]

1a Fine particles of polyethylene terephthalate mixed with metallic iron powder 1b Fine particles of other polyethylene and polystyrene 1 Mixed fine particles 2 Chute 3 Belt conveyor 4 Electromagnet 5 Scraper 6,7 Recovery box

Claims (3)

[Claims] 1. A polyethylene terephthalate product prepared by making a polymer in which a magnetic sensitive material is mixed in a condensate polymer of terephthalic acid and ethylene glycol, and molding a polyethylene terephthalate product with this polymer. 2. A polyethylene terephthalate product obtained by mixing a chip of a condensate polymer of terephthalic acid and ethylene glycol and a magnetic substance, and molding a polyethylene terephthalate product with this mixture. 3. A step of crushing or crushing a polyethylene terephthalate product mixed with a magnetic substance and a plastic product made of another material to obtain fine particles or flakes, and a step of adsorbing the fine particles or flakes to a magnet. And a method for separating polyethylene terephthalate products, which comprises a step of collecting fine particles or flakes adsorbed by a magnet.