# US 7,745,563 B2 · Method for processing polyester waste

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- Number: US 7,745,563 B2
- Document ID: US7745563B2
- Status: Granted
- Kind: B2
- Application number: 12/350,529
- Filed: 2009-01-08
- Published: 2009-05-14
- Granted: 2010-06-29
- Earliest claimed: 2002-05-23
- Assignees: PTP Group Ltd.
- Inventors: Viktor Bulgakov; Levan Dadiani; George Javakhishvili
- Web page: https://patentgrep.com/patent/US7745563B2

## CPC

- C08J 11/06: without chemical reactions
- C08G 63/6956: {Dicarboxylic acids and dihydroxy compounds}
- C08G 63/916: {Dicarboxylic acids and dihydroxy compounds}
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- Y02W 30/62: Plastics recycling; Rubber recycling
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A method for processing polyester wastes, especially used polyester bottles, which comprises shredding, washing, drying and melting the waste mixture to obtain a starting raw material wherein a modifying agent selected from the group comprising a combination of polysiloxane and a plasticizer selected from the group of phthalates, or a combination of silazanes and silanes is added to the shredded and dried waste mixture, the amount of the modifying agent being 4 to 6% by weight, based on the waste mixture.

## Claims

### Claim 1

A method for producing a modified polyester from waste processed polyester comprising:
1) shredding, washing, and drying waste processed polyester;
2) adding a modifying agent mixture consisting essentially of:
a) 20 to 30% by weight liquid polyhydrosiloxane; and
b) 70 to 80% by weight of a plasticizer selected from the group consisting of dioctylphthalate, dinonylphthalate, and dibutylsebacate;
wherein the modifying agent mixture is added in an amount of 4% to 6% by weight of the waste processed polyester;
3) heating the resulting mixture to obtain a melt; and
4) recovering a modified polyester.

### Claim 2 (depends on 1)

The method of claim 1, wherein the modifying agent mixture is added to the waste polyester at about 130° C., and the obtained polyester mixture is stirred for 50 to 100 minutes.

### Claim 3 (depends on 2)

The method of claim 2, wherein the polyester mixture is further heated to 240 to 250° C. to obtain a modified polyester.

### Claim 4 (depends on 3)

The method of claim 3, wherein the modified polyester is further processed to obtain a granulate.

### Claim 5

A method for producing a modified polyester from waste processed polyester comprising:
1) shredding, washing and drying waste processed polyester material;
2) adding a modifying agent mixture comprising:
a) 55 to 65% by weight hexamethyldisilazane; and
b) 35 to 45% by weight tetraethoxysilane;
wherein the modifying agent mixture is added in an amount of 4% to 6% by weight of the waste polyester;
3) heating the resulting mixture to obtain a melt; and
4) recovering a modified polyester.

### Claim 6 (depends on 5)

The method of claim 5, wherein the modifying agent mixture is added to the waste polyester at about 130° C., and the obtained polyester mixture is stirred for 50 to 100 minutes.

### Claim 7 (depends on 6)

The method of claim 6, wherein the melt is obtained by heating the polyester mixture to 240-250° C.

### Claim 8 (depends on 7)

The method of claim 7, wherein the modified polyester is further processed to obtain a granulate.

### Claim 9 (depends on 1)

The method of claim 1, wherein the resulting modified polyester has a crystallization temperature of about 110° C.

### Claim 10 (depends on 5)

The method of claim 5, wherein the resulting modified polyester has a crystallization temperature of about 110° C.

### Claim 11

A method for producing a modified polyester from waste processed polyester comprising:
1) shredding, washing, and drying waste processed polyester;
2) adding a modifying agent mixture consisting essentially of a) a combination of 20 to 30% by weight polyhydrosiloxane and 70 to 80% by weight of a plasticizer selected from the group consisting of dioctylphthalate, dinonylphthalate, and dibutylsebacate; or b) a combination of 55 to 65% by weight hexamethyldisilazane and 35 to 45% by weight tetraethoxysilane;
wherein the modifying agent mixture is added in an amount of 4% to 6% by weight of the waste processed polyester;
3) heating the resulting mixture to obtain a melt; and
4) recovering a modified polyester.