Homogenous copσlymeric material and process for its preparation

The present invention is directed to a homogenous copolymeric material and to a process for its preparation.

In the prior art it is believed that it is complicate or even not possible to obtain from a mixture of polar polymers - for example polyesters, such as PET or PC, - with nonpolar polymers - for example polyole- fins, such as PE (LDPE and HDPE) , PP - a homogenous copolymeric material. This belief is based on the different molecular structures of the polar and nonpolar polymers. Nonpolar polymers, such as PE or PP, have saturated and nonreactive stable hydrocarbon chains.

It is a fact that PET has a melting point from

253 ⁰ C to 255 ⁰ C, whereas PC has a melting point of about 255 ⁰ C. Thus, PET and PC may be mixed together in a melded state to a mixture that can be used afterwards in the injection moulding technology, but not in the extru- sion technology.

This means that neither PET nor PC nor their mixture may be used as a single component in the pipe production industry, despite the fact that their initial properties, such as their stiffness, would be much de- manded.

LDPE has a melting range from 112 ⁰ C to 135 ⁰ C, whereas PP has a melting range from 170 ⁰ C to 19O ⁰ C.

In WO 03/104314 Al is described a process for processing of polyester wastes, for example waste-PET.

Nothing is described in this reference about a mixing or further processing with any polymeric material.

In WO 2006/006064 Al is described crystallized PET, which contains silicon in a bounded and integrated into the molecular structure of PET form.

It is also described in this reference that this crystallized PET may be mixed in the sense of a plain mixture in any mixing ratio with any polymeric ma- terial, for example with PP or PC.

Thus, the resulting product is just a mechanical mixture of two different polymeric solids without any new chemical bond between them. Nothing is said in this reference about a further processing of this mix- ture .

It is an object of the present invention to provide a new homogenous copolymeric material with new properties and wide application possibilities.

One of the intended fields of application for this new homogenous copolymeric material shall be the pipe production.

It is a further object of the present invention to provide a so called "tailor made" new homogenous copolymeric material that meets requested values of cer- tain characteristics.

It is a further object of the present inven- ■ tion to reduce the year-to-year increasing amount of post-consumer polymeric waste by transforming it into a

convertible and demanded new homogenous copolymeric material that shall have a high market value.

It is a further object of the present invention to provide a simple and cost advantageous process for the preparation of this new homogenous copolymeric material .

With the present invention these objects are achieved.

The present invention is directed to a homoge- nous copolymeric material that is characterized in that it is built up of

- at least one polyester and/or fragments thereof ,

- at least one further polymer, that is not a polyester, and/or fragments thereof, and

- silicon as an interconnecting element between said polyester (s) and/or fragments thereof and said further polymer (s) and/or fragments thereof.

The inventive process for the preparation of the homogenous copolymeric material is characterized in that

- according to a first version

a.) at least one polyester and/or fragments thereof and at least one modifying agent, which contains silicon and which is able to connect together said polyester (s) and/or fragments thereof, are mixed and are al-

lowed to react to give a first semi-modified polymeric material ,

b.) at least one further polymer, that is not a polyester, and/or fragments thereof and at least one modifying agent, which contains silicon and which is able to connect together said polymer (s) and/or fragments thereof, are mixed and are allowed to react to give a second semi-modified polymeric material, and

c.) said first semi-modified polymeric mate- rial and said second semi-modified polymeric material are mixed together in the desired ratio and are extruded to a homogenous copolymeric material ,-

- according to a second version

d.) at least one polyester and/or fragments thereof and at least one further polymer, that is not a polyester, and/or fragments thereof are mixed together in the desired ratio, then at least one modifying agent, which contains silicon and which is able to connect together said polyester (s) and/or fragments thereof and said polymer (s) and/or fragments thereof, is added to the mixture and is allowed to react to give a semi- modified copolymeric material, and

e.) said semi-modified copolymeric material is extruded to a homogenous copolymeric material; and

f.) said extruded homogenous copolymeric material as received at the end of step c.) in the first version or said extruded homogenous copolymeric material as received at the end of step e.) in the second version is obtained.

The inventive homogenous copolymeric material may be used as

- a raw material for the preparation of products produced by an extrusion process, for example tubes, pipes, cable insulation, sheets, films,

- a raw material for the preparation of products produced by an injection molding process, for example rigid massive items, such as outdoor furniture, parts used in automotive industry, sheets, capsules to be used as a starting material for packaging, for example blown bottles,

- a raw material for the preparation of fibers.

Preferred embodiments of this invention are defined in the dependent claims.

In the following part are described possible embodiments of the present invention.

The following examples shall illustrate the present invention.

Example 1 (first version of the process)

54 kg of crushed, washed and dried flakes from waste-PET bottles, whereby these flakes had a size from 2 mm to 10 mm, and 1.35 kg of a mixture of 0.81 kg TOS (tetra ortho silicate) [Si (OC ₂ H ₅ ) J and of 0.54 kg HMDS (Hexamethyl-disilazane) were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of 13O ⁰ C by means of blowing hot air there through for 1 hour.

There results a first semi-modified polymeric material .

6 kg of PP in the form of new and fresh, so- called "virgin" , pellets having a size from 2 mm to 4 mm and 0.12 kg of polyethylhydrosiloxane were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of 120 ⁰ C by means of blowing hot air there through for 1 hour.

There results a second semi-modified polymeric material .

The obtained first semi-modified polymeric material and the obtained second semi-modified polymeric material were loaded through two separate dosing systems into the hopper of a twin-screw extruder.

Thereby was used a ratio of 90 parts per weight of semi-modified PET and 10 parts per weight of semi-modified PP.

Inside the extruder the resulting mixture was heated to a temperature of 250 ⁰ C to 260 ⁰ C. The residence time of the material inside the extruder was about 6 minutes.

The obtained homogenous copolymeric melt was Strand pelletized (in German: Stranggranulierung) by known standard technology.

There were obtained 58 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a dryer of an injection moulding device. Herein these pellets were dried for 6 hours at a temperature o£ 160 ⁰ C.

Afterwards they were transformed into bottle pre-forms by means of standard injection moulding techniques .

The obtained bottle pre- forms were suitable for bottle production by means of standard stretch- blowing technology.

Example 2 (first version of the process)

9 kg of PC in the form of parts of crushed compact discs (CD) , which were separated from impurities, such as aluminum, mechanical dirt and colorants, in the form of chips having a size from 4 mm to 10 mm and 0.225 kg of HMDS (Hexamethyl-disilazane) were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of 13O ⁰ C by means of blowing hot air there through for 1 hour.

There results a first semi-modified polymeric material .

21 kg of PP in the form of new and fresh, so- called "virgin" , pellets having a size from 2 mm to 4 mm and 0.42 kg of TOS (tetra ortho silicate) CSi (OC ₂ H ₅ ) J were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of 110 ⁰ C by- means of blowing hot air there through for 1 hour.

There results a second semi-modified polymeric material .

The obtained first semi-modified polymeric material and the obtained second semi-modified polymeric material were loaded through two separate dosing systems into the hopper of a twin-screw extruder. .

Thereby was used a ratio of 30 parts per weight of semi-modified PC and 70 parts per weight of semi-modified PP.

Inside the extruder the resulting mixture was heated to a temperature of 250°C to 260 ⁰ C. The residence time of the material inside the extruder was about 6 minutes.

The obtained homogenous cσpolymeric melt was Strand pelletized (in German: Stranggranulierung) by known standard technology.

There were obtained 27 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a pipe production device.

The pipes were produced by means of standard extrusion process at a temperature of 245 ⁰ C.

The diameter of the pipe was 16 mm, and the wall thickness of the pipe was 1.2 mm.

The modul factor and the break stress factor are increased significantly with regard to pipes made of PP.

Example 3 (second version of the process)

45 kg of crushed, washed and dried flakes from waste-PET bottles, whereby these flakes had a size from 2 mm to 10 mm, 5 kg of PP in the form of new and fresh, so-called "virgin", pellets having a size from 2 mm to 4 mm, 1.5 kg of PA-6 in the form of new and fresh, so- called "virgin" , pellets having a size from 2 mm to 4 mm and 1.25 kg of a mixture of 0.75 kg of TOS (tetra ortho silicate) [Si(OC ₂ H ₅ )J and 0.5 kg of HMDS (Hexamethyl- disilazane) were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of 120 ⁰ C by means of blowing hot air there through for 1 hour.

There results a semi-modified copolymeric ma- terial.

The obtained semi -modified copolymeric material was loaded into the hopper of a twin-screw extruder.

Inside the extruder the semi -modified copoly- meric material was heated to a temperature of 250 ⁰ C to 260 ⁰ C. The residence time of the material inside the extruder was about 6 minutes.

The obtained homogenous copolymeric melt was Strand pelletized (in German-. Stranggranulierung) by known standard technology.

There were obtained 50 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a dryer of an injection moulding device. Herein these pellets were dried for 3 hours at a temperature of 160 ⁰ C.

Afterwards they were transformed into bottle pre-forms by means of standard injection moulding techniques.

The obtained bottle pre-forms were suitable for bottle production by means of standard stretch- blowing technology.

These bottles had about 10 % better barrier properties than conventional PET-bottles.

Example 4 (second version of the process)

30 kg of crushed, washed and dried flakes from waste-PET bottles, whereby these flakes had a size from 2 mm to 10 mm, 30 kg of LDPE in the form of crushed, washed and dried flakes from post-consumer bottle caps, whereby these flakes had a size from 2 mm to 10 mm, and 1.20 kg of polyethylhydrosiloxane were mixed at room temperature in a mixing screw.

The obtained mixture was given into a mixing reactor and was heated up to a temperature of HO ⁰ C by means of blowing hot air there through for 1 hour.

There results a semi-modified copolymeric material.

The obtained semi-modified copolymeric mate- rial was loaded into the hopper of a twin-screw extruder .

Inside the extruder the semi-modified copolymeric material was heated to a temperature from 25O ⁰ C to 26O ⁰ C. The residence time of the material inside the ex- truder was about 6 minutes.

The obtained homogenous copolymeric melt was Strand pelletized (in German: Stranggranulierung) by known standard technology.

There were obtained 56 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a pipe production device.

The pipes were produced by means of standard extrusion process at a temperature of 245 ⁰ C.

The diameter of the pipe was 20 mm, and the wall thickness of the pipe was 2 mm.

The modul factor and the break stress factor are increased significantly with regard to pipes made of PE.

Example 5 (second version of the process)

There were processed as described in example 3 40 kg of waste~PET bottles, 6 kg of "virgin" PS and 1.150 kg of TOS (tetra ortho silicate) [Si(OC ₂ H ₅ )J .

There were obtained 46 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a dryer of an injection moulding device. Herein these pellets were dried for 3 hours at a temperature of 160 ⁰ C.

Afterwards they were transformed into bottle pre- forms by means of standard injection moulding techniques .

The obtained bottle pre-forms were suitable for bottle production by means of standard stretch- blowing technology.

These bottles had an about 5 % better thermo resistance than conventional PET-botfcles.

Example S (second version of the process)

There were processed as described in example 4 28 kg of PP, 12 kg of PET, modified as described in

WO 03/104314 Al ₇ and 600 g of TOS (tetra ortho silicate) [Si(OC ₂ H ₅ )J .

There were obtained 40 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a pipe production device .

The pipes were produced by means of Standard extrusion process at a temperature of 245°C.

There were produced pipes having a diameter of

20 mm and 16 mm.

Example 7 (second version of the process)

There were processed as described in example 4 15 kg of LDPE in the form of crushed, washed and dried flakes from post-consumer bottle caps, 35 kg of waste- PET bottles and 1 kg of polymethylhydrosiloxane .

There were obtained 50 kg of a new homogenous copolymeric material in the form of pellets having a size from 2 mm to 4 mm.

These pellets were loaded into a pipe production device.

The pipes were produced by means of standard extrusion process at a temperature of 245 ⁰ C.

There were produced pipes having a diameter of

20 mm and 16 mm.

In the following table are mentioned some properties of "virgin" materials and of the products as obtained in the above examples 1 to 7. In this table are mentioned in examples 1 to 7 the percentage numbers of the used starting polymers .

Table