WO2017116269A1

WO2017116269A1 - A composition of a concentrate, a method of production thereof and a method of increasing polymer viscosity

Info

Publication number: WO2017116269A1
Application number: PCT/RU2015/000960
Authority: WO
Inventors: Alexey Mikhailovich VOLKOV; Irina Gennadievna RYZHIKOVA
Original assignee: Sibur Holding PJSC
Current assignee: Sibur Holding PJSC
Priority date: 2015-12-30
Filing date: 2015-12-30
Publication date: 2017-07-06
Anticipated expiration: 2018-06-30
Also published as: RU2703130C1

Abstract

The present invention relates to a composition of a concentrate of additives representing polymer chain extenders, method for producing the composition of a concentrate and to a method for increasing a viscosity of a polymer, preferably secondary polyesters, for example, recycled polyethylene terephthalate (PET) by using the composition of a concentrate. Claimed is a composition of a concentrate for increasing a viscosity of polymer prepared by polycondensation, the composition comprising: a) compound selected from organic acid dianhydrides, and combinations thereof and b) compound selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof, and c) polymer base; wherein the mass ratio of the indicated components a) and b) is from 5: 1 to 1 :5. The method comprising mixing the components a) and b) at mixing rate of at least 1000 rpm during at least 2 minutes at temperature at least 30°C. Also claimed is a method for preparation a composition of a concentrate, method for increasing a polymer viscosity and polymer products obtained using the composition of the invention, and a moulded article prepared from polymer product.

Description

A COMPOSITION OF A CONCENTRATE, A METHOD OF PRODUCTION THEREOF AND A METHOD OF INCREASING POLYMER VISCOSITY

FIELD OF THE ART The present invention relates to a composition of a concentrate of additives representing polymer chain extenders, method for producing the composition of a concentrate and to a method for increasing a viscosity of a polymer, preferably secondary polyesters, for example, recycled polyethylene terephfhalate (PET) by using the composition of a concentrate. More specifically, the present invention relates to a composition of a concentrate that is introduced during the process of the reactive extrusion into a polymer to increase a viscosity thereof, and to a method for preparation of the composition of a concentrate.

PRIOR ART Secondary raw materials, for example PET plastic bottle waste products, are the important class of secondary raw materials, the considerable part of which is used to produce fibers for the manufacture of different kinds products: non- woven materials, carpeting materials, staple materials for clothes and sleeping bags, and the like.

However, properties of secondary raw material are not identical to those of polymers prepared for the 1^st time. The second raw materials have reduced molecular weight (MW) and, as a consequence, reduced intrinsic viscosity of the polymer melt. The melt viscosity reduction in turn limits the possibility of processing thereof and therefore production process of ready-to-use articles. Furthermore, products made of the raw materials are characterized by low heat- and frost-resistance and the physical and chemical properties thereof are not always satisfactory.

Taking the aforesaid into account, nowadays recycling of such raw polymer materials have certain limitations.

The main reason of such a worsening of properties of the secondary raw material is the chemical instability of chains of the polymers obtained by the polycondensation, for example such as PET. Terminal reactive functional groups can act as a source of such instability. Concentration of such groups considerably increases during the processing and further use of primary PET, since the structure of chains of such polymers is sensitive to thermal, thermal-oxidative and hydrolytic destruction.

Reaction schemes and the structure of the products formed after thermal- oxidative destruction of PET during the recycling the polymer in the melt are presented below in the scheme 1.

Scheme 1 Carboxyl- and vinyl-ester terminal groups are formed as the result of the above reaction. During further oxidation, the latter group forms a volatile and toxic

acetaldehyde, a mass concentration of which, as it is known from State Standard R 51695-2000 (chapter 5.3, table 3) in bottled PET shall not exceed 2 ppm.

Even small traces of water at temperatures of recycling PET can cause hydrolytic destruction of PET to form both cyclic and linear oligomer products, and macro chains which are short in comparison with to the initial material and have terminal carboxylic and alcohol groups (scheme 2):

Scheme 2

In order to extend and stabilize a polymer chain of macromolecules of secondary polyesters, various bifunctional compounds (chain extenders) are introduced on the stage of extrusion, the compounds react with terminal functional groups which leads to linear elongation of macromolecules.

Various approaches to extend polymer chains are known in the art.

One of the most common and technically applicable methods of recycling PET raw material includes chemical modification thereof by introducing chain extenders into the polymer PET matrix during the recycling treatment. These chain extenders are selected from bi- and/or poly-functional organic compounds, as a rule of aromatic nature, that comprise two or more functional groups within the plane of the aromatic ring, which groups while reacting with terminal functional groups of polymer chains, provide linear extension of macromolecules.

One of the first organic compounds used by researches for chemical modification of polyesters, in particular, recycled PET, were anhydrides.

The patent US5376734 (published 27 December 1994, the Applicant «M & G RICERCHE SPA [IT]») proposes a method of modifying PET possessing low initial value of intrinsic viscosity of less than 0.57 to values at the level of 0.8 dL/g. The method consists in the combination of steps of the reactive extrusion of the PET melt in the presence of PMDA (pyromellitic dianhydride) to lwt.% and a step of solid-phase polycondensation with the preliminary annealing of PET pellets to complete the crystallization process of polymer macromolecules. The step of solid phase polycondensation is carried out at the increased temperature for 12 hours. Within the method, a special twin-screw extruder is used at the step of the reactive melt extrusion (counter rotating and not-intermeshing) with low shear mixing to reduce the degradation of macromolecules of the polymer. The introduction of PDMA into the PET melt is carried out in the form a mixture of 20 wt.% PMDA in a powder PET preliminary dried under vacuum.

The same authors in the patent US5902864 (published 1 1 May 1999, the Applicant «SINCO ENG SPA [IT]») have proposed the new modification of the method of increasing the viscosity of PET raw material with the initial low value thereof, consisting in the use of PMDA additive to 0.6wt.% in the PET melt, but already directly into the reactor at the end of the polycondensation process (not during the extrusion process), thereby significantly increasing the contact time of the additive with the polymer. The remaining steps are carried out in a similar manner with respect to the previous method. Drawbacks of said method are the multistage of the modification process of the recycled PET, and also the necessity of the use of special equipment.

Also the prior art discloses a use as polyester chain extenders, additives on the base of aromatic acid dianhydrides and phosphonic acid esters and half esters with sterically hindered phenol compounds. The application W09523176 (published 31 August 1995, the Applicant «CIBA GEIGY AG [CH]; Pfaendner Rudolf [DE], Herbst Heinz [DE], Hoffmann Kurt [DE]») discloses a method for increasing a molecular weight of polyesters, including secondary polyesters, with a modifyingsystem comprising dianhydride, preferably PMDA, and esters, half esters of phosphonic acid with sterically hindered phenol compounds. A quantity of the introduced PMDA and phosphorous-containing compounds is up to 5wt.%. A laboratory method of compounding PET and additives is presented in this document. The ingredients of additive are mixed in a glass reactor with stirring at a temperature of 280°C for 20 minutes. This method allows to increase the viscosity of the recycled PET from 0.46 dL/g to 0.83 dL/g. Within the method it is required to conduct a time-spending mixing process. Moreover, for cerain polyester application it is required to obtain higher levels of intrinsic viscosity, up to 1,0 dL/g and even higher.

It is reported in patent US5776994 (published 07 July 1998 for the name

«SINCO ENG SPA [IT]») about an unexpected effect that is provided by the use of the preliminary obtained concentrate of an additive-modifier comprising PMDA in a polycarbonate polymer base for the modification of the rheology of PET (Dow Calibre 0201-10). It is reported that the use of polyesters as the polymer base for the additive results in the early sudden increase of the molecular weight and formation of gel-fraction of products in the course of the extrusion.

Further l ,3(l ,4)-phenylene-bis-oxazoline (PBO) is known as an effective extender of polyester chains. As well as PMDA, the indicated compound binds two terminal carboxyl groups of polyesters without releasing volatile condensation side products.

The effect of the use of PBO as the extender of PET chains in the melt extrusion process on a standard extrusion equipment is studied in the document (Karayanidis G.P., and Psalida E.A. Chain extension of recycled PET with 2,2 -(l ,4-phenylene)bis(2- oxazoline), J. APPL. Polymer Sci., 77,2206, 2000). The preliminary treatment of PET at the terminal hydroxyl groups with phthalic anhydride is carried out during the extrusion. This treatment resulted in the considerable increase of the concentration of terminal carboxyl groups of thus modified PET, which notably increased the efficacy of PBO at the following step of the treatment of the polymer. This approach for solving the problem of increasing the viscosity of the recycled PET is also disclosed in article (Bo Liu and Qianwei Xu. Effects of Bifunctional Chain Extender on the Cristallinity and Thermal Stability of PET. Journal of Materials Science and Chemical Engineering, l, p.9-15, 2013). Authors of this document have shown that the growth of intrinsic viscosity of the polymer from the initial value 0.61 dL/g to 0.8 dL/g at a PBO dosage of 0.52 wt.% occurs upon the interaction of oxazoline compound only with only one carboxyl group of the PET. The additional increase of intrinsic viscosity of the recycled PET to the value of 0.83 dL/g takes place in the case of combined use of PBO with a chain extender (which is 2,2'-(l ,4-phenyl)bis(4H-3,l-benzoxazolin-4-one) capable of reacting with OH-groups of the PET.

Thus, it is shown in documents of the state of the art that the combined use of additives - chain extenders working according to different mechanisms of interacting with terminal polymer prepared by polycondensation, in particular, PET, may be effective from the point of view of increasing the viscosity of the obtainable polymer product. At the same time, there are data about the use of chain extenders in the form of the preliminary prepared concentrates on the polymer base or being preliminary mixed thoroughly in fine-grained, highest possible dry form under vacuum or in the inert atmosphere to increase the molecular weight of polyesters.

The above described reaction extrusion processes allow to reduce substantially recycling costs for secondary polymer raw materials, in particular, secondary PET, however, it is still not possible to guarantee the viscosity increase to the level wherein the material is suitable for making plastic bottles (0.8 dL/g and more). It is still desirable to further increase the secondary polymer viscosity to the level of 1.0 dL/g or higher in order to widen application thereof, and simultaneously avoid using additional condensation steps.

So the problem to increase of the polymer viscosity, in particular polyester viscosity, is still actual. This problem is especially actual in case of secondary PET raw materials for solving the problem of more effective recycling of such a material. Thus, the increase of viscosity of the recycled polyesters, in particular recycled PET, to values of 0.80 to 1.00 dL/g and more allows using this raw material not only for the manufacture of bottles, but also for the formation of films, sheets, including foamed materials, and also for the manufacture of articles by the blow moulding method.

Also the problem to be solved is to increase intrinsic viscosity of melt polymer, such as polyesters, polyamides, polycarbonates, using economically effective method and having minimal time spent, this enhancing technological properties of the obtained polymer.

BRIEF DESCRIPTION OF THE INVENTION

The object of the present invention is a composition of a concentrate for increasing a viscosity of polymer prepared by polycondensation, the composition comprising:

a) compound selected from organic acid dianhydrides, and combinations thereof and b) compound selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof, and

c) polymer base;

wherein the mass ratio of the indicated components a) and b) is from 5:1 to 1 :5. In the preferable embodiment, the component a) is selected from aromatic acid dianhydrides and mixtures thereof; more preferably, from pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPDA), oxydiphthalic dianhydride (ODPDA), and combinations thereof.

In the preferable embodiment, the component b) is selected from bis-oxazolines with aromatic fragments, and the aromatic fragment preferably selected from C5-C10-aryl or C5-C10-heteroaryl. In more preferable embodiment for the component b) is selected from 1,3 (l,4)-phenylene-bis-oxazoline (PBO), 3,3 '(3,4';3,5')-naphthylene-bis- oxazoline (NBO), 4,4'(3,3';3,4^,;3,5')-di-phenylene-bis-oxazoline (DPBO), and combinations thereof.

In the preferred embodiment, the polymer base identical for at least 50% to the polymer raw material which is subjected to viscosity increase from the point of view of chemical formulation. More preferably, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate and combinations thereof are used as c) polymer base.

Further object of the present invention is a method for preparing the composition of a concentrate, the method comprising the stages:

i) providing a mixture of the component a) compound, selected from organic acid dianhydrides, and combinations thereof; b) compound selected from bis-, tris-, and tetrakis-oxazolines and combinations thereof; and c) polymer base;

ii) mixing the components indicated on the stage (i) at mixing rate of at least 1000 rpm during at least 2 minutes at temperature at least 30°C.

Yet another object of the present invention is a method of increasing viscosity of the polymer prepared by polycondensation comprising the stages: i) adding of a feed polymer into an extruder;

ii) adding of a composition for increase a polymer viscosity, the composition comprising:

a) compound, selected from organic acid dianhydrides, and combinations thereof;

b) compound selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof; and c) polymer base;

wherein the mass ratio of the indicated components a) and b) is from 5: 1 to

1 :5;

iii) extruding of the thus obtained mixture to obtain a polymer product.

Yet another object of the present invention relates to use of the composition of a concentrate to increase polymer viscosity.

The present invention also relates to a polymer product prepared using the composition of a concentrate of the invention, and a moulded article obtained from the above indicated polymer product.

DETAILED DESCRIPTION OF THE INVENTION

The goal of the present invention is to provide an effective modifying additive allowing to increase an intrinsic viscosity value of polymer raw material, more particularly, polyesters, for example, PET, to the level of 0.8 dL/g or higher.

The inventors of the present invention surprisingly found that the problem can be solved by addition during the reaction extrusion of a polymer a mixture a) compounds selected from organic acid dianhydrides, more preferably aromatic acid dianhydrides and combinations thereof; among them more preferably, from pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPDA), oxydiphthalic dianhydride (ODPDA), and combinations thereof and the component b) is selected from bis-oxazolines with aromatic fragments, even more preferably selected from 1 ,3 (1 ,4)- phenylene-bis-oxazoline (PBO), 3,3'(3,4';3,5')- naphthylene-bis-oxazoline (NBO), 4,4'(3,3';3,4';3,5')-di-phenylene-bis-oxazoline (DPBO), and mixtures thereof. In the process of research the most effective chain extender, the inventors found a preference of combination of mixture a) compound selected from organic acid dianhydride with b) compounds selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof, on increase a viscosity of a polymer, in particular, PET.

It is preferable to use a) compound selected from organic acid dianhydrides and b) compound selected from bis-, tris- and tetrakis-oxazolines mass ratio from 5: 1 to 1 :5, more preferably from 3: 1 to 1 :3, and even more preferably from 2: 1 to 1 :2. In a preferred embodiment, the ratios are used with excess of dianhydride, i.e. a) compound selected from organic acid dianhydrides and b) compound selected from bis-, tris- and tetrakis-oxazolines mass ratio from 5: 1 to 1.5: 1 , more preferable from 3: 1 to 2: 1.

Furthermore, it has been found that adding c) polymer base allows effective increase of viscosity of a polymer during the reaction extrusion thereof. Further increase of quantity of introduced composition of a concentrate (till 10wt% counting to total content of the composition of a concentrate in the polymer) allows to achieve viscosity of 1.2 dL/g or more.

So the object of the present invention is a composition of a concentrate for increasing a viscosity of polymer prepared by polycondensation, the composition comprising:

a) compound selected from organic acid dianhydrides, more preferably aromatic acid dianhydrides, preferably selected from pyromellitic dianhydride (PMDA), 3,3',4,4'- benzophenone tetracarboxylic dianhydride (BPDA), oxydiphthalic dianhydride

(ODPDA), and combinations thereof;

b) compound selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof, more preferably, from bis-oxazolines with aromatic fragments, and the aromatic fragment preferably selected from C5-C10-aryl or C5-C10-heteroaryl. In more preferable embodiment for the component b) is selected from 1,3 (l ,4)-phenylene-bis- oxazoline (PBO), 3,3'(3,4';3,5')- naphthylene-bis-oxazoline (NBO),

4,4'(3,3';3,4';3,5')-di-phenylene-bis-oxazoline (DPBO), and combinations thereof, and c) polymer base;

wherein the mass ratio of the indicated components a) and b) is from 5: 1 to 1 :5.

POLYMER RAW MATERIAL

Although, as it is indicated above, for the secondary raw materials of PET the problem of increasing the polymer viscosity by extending chains is especially actual, the proposed composition may be used for the chain extension of any polymer having end functional groups. In particular, suitable polymers are the polymers obtained by polycondensation of at least two different monomers, including polyesters, polyamides and polycarbonates and the like other than the PET, i.e. polymers which comprise in the structure thereof end functional groups capable of reacting to chain extenders, namely such groups as: carboxyl group, hydroxyl group, amide group, amine group and the like. More specifically, the proposed composition of the concentrate may be used for increasing viscosity of any polyesters, upon the synthesis of which carboxylic acids, glycols and other polyfunctional alcohols, and (or) di-, tri- and polyamines are used as co-monomers.

Aliphatic dicarboxylic acids may have a linear or branched carbon chain of 2 to 40 atoms. Examples of these acids are, in particular, oxalic acid, malonic acid, adipic acid.

The cycloaliphatic carboxylic acids may contain 2 to 6 carbon atoms, aromatic acids may contain 8 to 18 carbon atoms. Examples of cycloaliphatic acids are, in particular, 1,3-cyclobutanedicarboxylic acid, 1 ,3-cyclopentanedicarboxyIic acid, 1 ,3- and 1 ,4-cyclohexanedicarboxylic acid.

Suitable aromatic acids are phthalic acid and terephthalic acid, isophthalic acid, o-phthalic acid, and also 1,3-, 1 ,4-, 2,6- or 2,7-naphthalenedicarboxylic acid, 4,4'- diphenyldicarboxylic acid.

Suitable aliphatic diols are linear and branched aliphatic diols, preferably those containing 2 to 12 carbon atoms, most preferably 2 to 6 carbon atoms. Examples of these aliphatic diols are ethylene glycol, 1,2- and 1 ,3-propylene glycol; 1 ,2-, 1 ,3-, 2,3- or 1 ,4-butanediol; pentyl glycol; neopentyl glycol, 1,6-hexanediol, 1, 12-dodecanediol.

Cycloaliphatic diols, for example 1 ,4-dihydroxycyclohexane, and also aromatic diols, for example p-xylcnc glycol, and also oligomeric and polyalcohols, for example diethylene glycol, triethylene glycol, and polyethylene glycol, are also suitable in the context of the presented invention.

The use of alkylene glycols, which are linear and have an amount of 2 to 4 carbon atoms, is preferable.

Ethylene glycol and butanediol are the most preferable aliphatic diols.

Suitable aliphatic diamines are linear and branched aliphatic diamines, preferably having an amount of 2 to 12 carbon atoms. Examples of these amines are 1 ,6- diaminohexane, 1 ,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminooctane. At the same time, if polymers are made of at least two monomers, their distribution may be both static and block.

PET, PBT and their corresponding copolymers are especially suitable for use as polyesters, wherein PET and copolymers thereof are especially preferred. The proposed composition also has the special importance in case of the use for increasing the viscosity of raw materials of PET articles returned for recycling, for example, from bottle collectors, for example, from collectors of waste of the manufacture of drinks. These materials preferably contain terephthalic acid, 2,6-naphthalenedicarboxylic acid and/or isophthalic acid in combination with ethylene glycol and/or 1,4- bis(hydroxymethyl)cyclohexane.

Generally, the present invention will have special importance in case of the use of secondary raw materials on the basis of polymers obtained by polycondensation. Products, which undergo various thermal and/or hydrolytic destruction, relate to these raw materials. It should also be taken into account that these recyclates may contain minor amounts of mixtures of polymers having different structures, for example, such as polyolefins, polyurethanes, acrylonitrile-butadiene-styrene (ABS) or polyvinylchloride (PVC). The indicated recyclates may also contain standard impurities for these waste products, for example small amount of paper, glue, traces of metals, and also oils or inorganic salts.

The especially preferable polyester is a PET used for the manufacture of bottles by blow moulding method. The use of polyesters recycled from different industrial processes is also possible.

COMPONENT (A) OF THE COMPOSITION OF A CONCENTRATE. ORGANIC ACID DYANHYDRIDES As it was indicated above, the component a) of the composition of a concentrate represents organic acid dianhydrides. Under the term, within the present invention organic compound is meant including at least to anhydride groups and binding hydrocarbon fragment. The binding fragment can be aliphatic or aromatic, preferably, aromatic.

Preferably the compounds are selected from aromatic acid dianhydrides, and combinations thereof; among them more preferably, from pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPDA), oxydiphthalic dianhydride (ODPDA), and combinations thereof.

COMPONENT (B) OF THE COMPOSITION OF A CONCENTRATE. BIS-, TRIS- AND TETRAKIS-OXAZOLINES As a component b) of the composition of a concentrate bis-, tris- and tetrakis- oxazolines and the combinations thereof are used.

Such compounds include at least two oxazoline moieties are binded with each other any acceptable way, for instance, the moieties can be condensed with cyclic fragment which is preferably aromatic. Preferable are bis-oxazolines with aromatic fragments. In more preferable embodiment for the component b) is selected from 1,3 (l,4)-phenylene-bis-oxazoline (PBO), 3,3'(3,4';3,5')-naphthylene-bis-oxazoline (NBO), 4,4'(3,3';3,4';3,5')-di-phenylene-bis-oxazoline (DPBO), and combinations thereof.

COMPONENT C) OF THE COMPOSITION OF A CONCENTRATE. POLYMER BASE.

Polycondensation polymers may be used as the polymer base for producing the composition of the concentrate, as described above. In whole the polymers, upon the synthesis of which glycols and other polyfunctional alcohols and (or) di-, tri- and polyamines are used as co-monomers, in particular, polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), are preferable.

The especially advantageous for use as the polymer base is the various secondary polyester raw materials, for example, injection molding waste of the manufacture of primary polyesters, milled waste materials of bottle tare, waste materials representing dust fractions accumulated on the filtration equipment and the like. It is preferable to use a polymer that by its nature is identical to the polymer that should be subjected to the modification as the initial polymer base for the manufacture of the concentrate. At the same time, the viscosity value of the polymer base is in the range of 0.5 to 0.8 dL/g. Thus, the use of the secondary raw materials for the polymer base of the concentrate is the additional source of recycling the secondary polymer raw materials.

In case of use of the polymer base it is presentable to choose the base that will coincide by the chemical nature with the polymer raw materials that is subjected to the increase of viscosity, partially or entirely (at least for 50wt%). To modify polyethylene terephthalate it is preferably to use polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN), or combinations thereof. It is also preferable to use a mixture wherein the PET content is more than 20 %wt.

The mass ratio of the component (c) polymer base to other components a) and b) is from 10: 1 to 1 : 1.5, preferably from 8: 1 to 3 : 1 , even more preferably from

6: 1 to 5: 1.

PREPARATION OF THE COMPOSITION OF A CONCENTRATE

Further object of the present invention is a method for preparing the composition of a concentrate, the method comprising the stages: i) Providing a mixture of the component a) compound, selected from organic acid dianhydrides, and combinations thereof; b) compound selected from bis-, tris-, and tetrakis-oxazolines and combinations thereof; and c) polymer base;

ii) Mixing the components indicated on the stage (i) at mixing rate of at least 1000 rpm during at least 2 minutes at temperature at least 30°C. It is preferable to grind preliminary the polymer base to particle size from 0,05 mm to 5 mm. It is also preferable that the grinded polymer base is dried to moisture content not more than 0,02 wt.%.

Mixing of the composition of a concentrate is provided under mixing speed from

1000 to 5000 rpm, preferably from 1500 to 4000, most preferably 3000 rpm during not less than 2 minutes, preferably from 2 to 10 minutes, more preferably from 2,2 to 5 minutes. If mixing is conducted using smaller velocities does not guarantee enough level of mechanical-chemical activation of components of the composition of a concentrate.

Any suitable high speed mixing device can be used which is to provide able enough level of mechanical-chemical activation of components of the composition of a concentrate, of determined mixture volume.

Components of the composition of the concentrate are loaded into the mixer in any order.

As indicated above, mixing temperature is maintained on the level higher than room temperature. Preferable temperature range for mixing components is from 30 to 200°C, more preferable from 45 to 150 °C, most preferable from 70 to 135 °C.

It was found that the composition of a concentrate prepared by mixing of the components thereof in high velocity rate mixer under increased temperature with dried and grinded polymer base allows to significantly increase a viscosity of a secondary polyester while introduced during the reactive extrusion of the polyester.

It can be suggested that the effect is due to the fact that the components a) and b) absorbed with the surface of the polymer base c) at temperatures higher that glass transition temperature (conventionally more than 70 °C) of component (c) in high shear dynamic regime, generated in the high speed mixer, chemical reaction occurs, probably, condensation reaction between corresponding functional groups with formation of long branched chain structures which probably can be partially grafted to the surface of the polymer base c). The indicated reaction allows to achieve a high branching rate and even curing of the chains of polyesters already on the stage of extrusion at elevated temperatures.

Concluding the inventors believe that addition of the composition of a concentrate according to the invention into polymer allows to achieve in fact any value of the intrinsic viscosity of the polymer product independently on viscosity value of the polymer raw material. The composition of a concentrate is prepared as described above and then introduce into a polymer feed with the use of standard dosing equipment on the extrusion line in use: dosing may be carried out through the main feeder in combination with the main feed polymer, or through the side feeder.

Quantity of the introduced composition of a concentrate is defined taking into account initial value of the polymer feed and desired viscosity value of the end polymer product. The extrusion temperature is conventional and is defined by properties of the modifiable polymer.

Concluding, technical result of the present invention consists in increasing of polymer viscosity, especially PET viscosity, to the values from 0.8 to 1.0 dT/g and more. Such modification on secondary PET raw material allows using this raw material not only for the manufacture of bottles, but also for the formation of films, sheets, including foamed materials, and also for the manufacture of articles by the blow molding method.

The following object of the present invention is the polymer product obtained by the method according to the invention by the addition of the concentrate into the polymer raw materials in the process of extrusion.

Polymer products obtained by the method according to the invention are characterized by intrinsic viscosity within the range of 0.8 to 1.5 dL/g and suitable for use as valuable polymer raw materials by traditional and acceptable in this field by traditional and acceptable methods of use, for example, for forming films, sheets, including foamed materials, and also for the manufacture of articles by blow moulding method.

The following subject matter of the present invention is the molded article obtained from the polymer product according to the invention. These molded articles may be films, sheets, and foamed materials.

The invention will be further illustrated by examples, which are presented for illustration of the present invention and are not recognized to limit the scope thereof.

EXPERIMENTAL EXAMPLES

As a polymer base 4 kinds of secondary raw materials were used: 2 kinds of injection molding waste of the industrial manufacture of primary PET with the initial viscosity value [η]=0.56 dL/g and [η]=0.53 dL/g, milled waste products of bottle tare (flexes) with the initial viscosity value [η]=0.78 dL/g and powder-like PET - waste products representing dust-like fractions accumulated on the filtration industrial equipment.

PET manufactured according to State Standard R 51695-2000 with the passport value of the intrinsic viscosity = 0.80 dL/g was used as the primary raw materials.

The main arbitrary notations and abbreviations MW - molecular weight;

PA - phthalic anhydride PMDA - pyromellitic di anhydride;

BPDA - benzophenone tetracarboxylic dianhydride;

ODPDA - oxydiphthalic dianhydride;

PBO - phenylene-bis-oxazoline

NBO - naphthylene-bis-oxazoline;

DPBO - diphenylene- bis-oxazoline;

PET - polyethylene terephthalate;

PBT - polybutylene terephthalate;

PEN - polyethylene naphtalate

Component a) of the composition

pyromellitic dianhydride (PMDA)

3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPDA)

oxydiphthalic dianhydride (ODPDA) component b) of the composition

1,3 (l,4)-phenylene-bis-oxazoline (PBO),

3,3'(3,4';3,5')- naphthylene-bis-oxazoline (NBO),

4,4'(3,3';3,4';3,5')-di-phenylene-bis-oxazoline (DPBO),

The preparation of compositions is carried out on twin-screw laboratory extruder LTE -20-44 with L/D=44 of the LabTech production, Thailand.

The intrinsic viscosity was measured according to State Standard R 51695-2000 in the solution 50:50% of ortho-dichlorobenzene and phenol at 25°C with the use of viscometer Ubbelode having a capillary diameter of 0.84 mm, the capillarity constant of 0.03mm²/sec² and the solvent outflow time of 108.72 sec, and also on the viscometer of trademark VPJ-1 having a capillary diameter of 0.86 mm, the capillarity constant of 0.03mm²/sec² and the solvent outflow time of 97.9 sec.

Example 1. A method of preparing the composition of a concentrate using high velocity mixer IKA M20 (Germany)

A sample of the recycled PET (regrind) preliminary dried and, if necessary, kept at the temperature from 80 °C to 150°C in the vented oven. Then the samples were taken from the oven and dosed without substantial cooling into a chamber of the high velocity mixer IKA M20 (Germany), the chamber volume is 100 cm³. In the chamber, PBO and PMDA were preliminary added in required ratio. Then the chamber was immediately closed, joined to the mixer starter and started the engine. Then mixing occurred of the dry components of the composition of a concentrate at rotation rate not less than 3000 rpm for 2 to 5 minutes. The ready-to-use composition of a concentrate was discharged and used to prepare a formulation by introducing into the charge of the recycled PET in the hermetic plastic container for the following extrusion on line LTE- 20-44.

According to the procedure described in example 1, concentrates (K1 -K23) with different ratio and different nature of initial components were prepared (Table 1.).

Table 1. The formulation of the concentrates prepared according to the procedure of example 1

CN CN CN CN CN CN CN CN

O O O O o O O O co co co co co co

oo

o o

O O O O O O O

00 00 oo 00 00 00 00

^

o

^ o o

o O

2? O o o

*-?

o O

O

O O

SO t-- 00 OS O CN

( CN CN CN Example 1-1. Preparation of the composition of a concentrate using high velocity mixer Henschel (Germany) .

Sample of the preliminary dried secondary PET (regrind) was placed into a chamber of high velocity mixer Henschel (Germany) with chamber volume equal to 1000 CM^j PMDA and PBO were also placed therein in required quantities. The chamber was kept at the temperature of 85 °C by adding the hot water into the heat transfer contour. Then mixing occurred of the dry components of the composition of a concentrate at rotation rate from 300 rpm to 3000 rpm for 3 to 5 minutes. The ready- to-use composition of a concentrate was discharged, cooled and used to prepare a formulation by introducing into the charge of the recycled PET in the hermetic plastic container for the following extrusion on line LTE-20-44.

Using the method described in the example 1-1 the compositions ( 24-K27) were prepared illustrating different rotation rates. (Tabl.2).

Table 2. Compositions of a concentrate prepared according to the example 1-1.

c m

m

c

Example 2. The use of concentrate Kl for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out in twin-screw extruder LTE 20/44 upon dosing the concentrate in an amount of 10 wt.% into the charge of the recycled PET. The temperature according to extruder zones: 255-260-265-270-275-280- 280-280-280-270-260°. Screw rotation speed is 120 rpm. The productivity of the extruder is 3 kg/h.

The intrinsic viscosity of the final product: 1.24 dL/g Example 3. The use of concentrate Kl for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate Kl in an amount of 3 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.63 dL/g

Example 4. The use of concentrate Kl for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K3 in an amount of 5wt.% into the charge of the composition, total additives content PMDA+PBO lwt.%.

The intrinsic viscosity of the final product: 0.87 dL/g

Example 5. The use of concentrate Kl for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate Kl in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.06 dL/g

Example 6. The use of concentrate K2 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate 2 in an amount of 3wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.60 dL/g

Example 7. The use of concentrate K2 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K2 in an amount of 5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.73 dL/g

Example 8. The use of concentrate K2 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K2 in an amount of 7wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.90 dL/g Example 9. The use of concentrate K3 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example-2 upon dosing the concentrate K3 in an amount of 5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.68 dL/g

Example 10. The use of concentrate K3 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example-2 upon dosing the concentrate K3 in an amount of 7wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.77 dL/g Example 11. Comparative. The use of concentrate K4 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 in an amount of 2.5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.54 dL/g

Example 12. Comparative. The use of concentrate K4 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 control in an amount of 5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.55 dL/g Example 13. Comparative. The use of concentrate K4 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 in an amount of 7.5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.53 dL/g

Example 14. Comparative. The use of concentrate K4 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 control in an amount of 10 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.57 dL/g Example 15. Comparative. The use of concentrate K4 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 in an amount of 12,5 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.56 dL/g Example 16. Comparative. The use of concentrate K4 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K4 control in an amount of 15wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.53 dL/g

Example 17. Comparative. The use of concentrate K5 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K5 in an amount of 2.5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.55 dL/g

Example 18. Comparative. The use of concentrate K5 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K5 control in an amount of 5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.57 dL/g

Example 19. Comparative. The use of concentrate K5 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate 5 in an amount of 7.5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.55 dL/g Example 20. Comparative. The use of concentrate K5 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example-2 upon dosing the concentrate K5 in an amount of 10 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.54 dL/g

Example 21. Comparative. The use of concentrate K5 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K5 in an amount of 12.5 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.54 dL/g Example 22. Comparative. The use of concentrate K5 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K5 in an amount of 15wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.53 dL/g

Example 23. Comparative. The use of concentrate K4-1 (PMDA 10%wt) and K5-1 (PBO 10 %wt) and recycled PET (80%wt.) the composition prepared without using high rate mixing, for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out by adding the composition of a concentrate K4-1+K5-1 in a ratio of 1 : 1. in an amount of 5wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.58 dL/g

Example 24.

Comparative. The use of concentrate K4-1 (PMDA 10%wt) and K5-1 (PBO 10 %wt) and recycled PET (80%wt.) the composition prepared without using high rate mixing, for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g The modification of the recycled PET was carried out by adding the composition of a concentrate K4- 1 +K5- 1 in a ratio of 1 : 1. in an amount of 20wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.69 dL/g

Example 25. The use of concentrate K6 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the PBT was carried out according to example 2 upon dosing the concentrate K6 in an amount of lOwt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.82 dL/g

Example 26. The use of concentrate K7 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the secondary PET was carried out according to example 2 upon dosing the concentrate K7 in an amount of 3.3wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.83 dL/g

Example 27. The use of concentrate K8 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K8 in an amount of 2.5 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.80 dL/g

Example 28. The use of concentrate K9 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K9 in an amount of 1.67wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.73 dL/g

Example 29. Comparative. The use of concentrate K10 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K10 in an amount of 7wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.79 dL/g

Example 30. Comparative. The use of concentrate Kll for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate Kl l in an amount of 7wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.84 dL/g

Example 31. The use of concentrate K12 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K12 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.88 dL/g

Example 32. The use of concentrate K13 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K13 in an amount of 7 wt.% into the charge of the composition. The intrinsic viscosity of the final product: 0.90 dL/g

Example 33. The use of concentrate K14 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K14 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.89 dL/g Example 34. The use of concentrate K15 for the modification of recycled

PBT having the intrinsic viscosity of 0.61 dL/g

The modification of the recycled PBT was carried out according to example 2 upon dosing the concentrate K15 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.95 dL/g

Example 35. The use of concentrate K16 for the modification of recycled PEN having the intrinsic viscosity of 0.67 dL/g

The modification of the recycled PEN was carried out according to example 2 upon dosing the concentrate K16 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.99 dL/g

Example 36. Comparative. The use of concentrate K17 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K17 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.64 dL/g

Example 37. The use of concentrate K18 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate 18 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.04 dL/g

Example 38. The use of concentrate K19 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K19 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.02 dL/g

Example 39. The use of concentrate K20 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K20 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.02 dL/g

Example 40. The use of concentrate K21 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate 21 in an amount 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.01 dL/g

Example 41. The use of concentrate K22 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K22 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.01 dL/g

Example 42. The use of concentrate K23 control for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K23 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 1.00 dL/g

Example 43. Comparative. The use of concentrate K24 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K24 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.67 dL/g

Example 44. Comparative. The use of concentrate K25 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K25 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.73 dL/g

Example 45. The use of concentrate K26 for the modification of recycled

PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K26 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.87 dL/g

Example 46. The use of concentrate K27 for the modification of recycled PET having the intrinsic viscosity of 0.53 dL/g

The modification of the recycled PET was carried out according to example 2 upon dosing the concentrate K27 in an amount of 7 wt.% into the charge of the composition.

The intrinsic viscosity of the final product: 0.89 dL/g

The comparative example 36 is to demonstrate that if the component a) is taken from other compounds, for example phtalic anhydride, the intrinsic viscosity of the product is not sufficiently high. The viscosity does not increase significantly in the case of using only component a) (Examples 1 to 16) or only b (claims 17 to 22) in the composition of a concentrate. So the experiments lead to the conclusion that the combination of components a) and b) is effective (examples 2-5, 37-42).

Comparative examples 29 and 30 demonstrate that it is preferable to obtain the composition of the concentrate at elevated temperatures, which is desirably not less than 70°C, since the example 8 using the composition formed at elevated temperature allows to achieve a higher viscosity of the same polymer raw material.

It is also demonstrated that it is preferable to use a high speed mixing of the composition components not less than 2000 rpm during not less than 2 minutes at temperature not less than 70°C. In particular, 10% wt of the composition, prepared usin the high speed mixing at temperature of 130 °C when used to modify he secondary PET, according to the example 1 , allows to obtain 134 % increase viscosity thereof to values 1 ,24 dL/g, and in the absence of high speed mixing (examples 23 and 24) viscosity 20 % increase only for is achieved.

Concluding, the best mode for achievement the claimed technical result is using the composition of the concentrate including the components a) and b) mixed with dried milled polymer base using mixing speed not less than 1000 rpm, preferable not less than 3000 rpm at temperature from 70 to 130 °C.

Furthermore, intruding of larger amount of the composition of a concentrate to the secondary polyester allows to significantly increase its viscosity to the required amount. In particular, 10 %wt introduced into secondary polyester allows to achieve 134% increase of viscosity thereof to value of 1.24 dL/g (example 1).

Claims

1. A composition of a concentrate for increasing a viscosity of polymer prepared by polycondensation, the composition comprising: a) compound selected from organic acid dianhydrides, and combinations thereof and b) compound selected from bis-, tris- and tetrakis-oxazolines, and combinations thereof, and c) polymer base; wherein the mass ratio of the indicated components a) and b) is from 5: 1 to 1 :5.

2. The composition according to claim 1 , wherein the component a) is selected from aromatic acid dianhydrides and combinations thereof.

3. The composition according to claim 2, wherein the component a) is selected from pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPDA), oxydiphthalic danhydride (ODPDA), and combinations thereof.

4. The composition according to claim 1, wherein the component b) is selected from bis-oxazolines with aromatic fragments.

5. The composition according to claim 4, whereinthe aromatic fragment preferably selected from C5-C10-aryl or C5-C10-heteroaryl.

6. The composition according to claim 5, wherein the component b) is selected from 1,3 (l ,4)-phenylene-bis-oxazoline (PBO), 3,3'(3,4';3,5')- naphthylene-bis-oxazoline (NBO), 4,4'(3,3';3,4';3,5')-di-phenylene-bis-oxazoline (DPBO), and combinations thereof.

7. The composition according to claim 1 , wherein the mass ratio of the components a) and b) is from 3: 1 to 1 :3, preferably from 2: 1 to 1 :2.

8. The composition according to claim 1 , wherein the mass ratio of the components a) and b) is from 5: 1 to 1 ,5: 1, most preferable from 3: 1 to 2:1.

9. The composition according to claim 1, wherein the polymers prepared by polycondensation are selected from polymers, upon the synthesis of which glycols and other polyfunctional alcohols, and (or) di-, tri- and polyamines, and combinations thereof are used.

10. The composition according to claim 1, wherein the polymers prepared by polycondensation are selected from polymers upon the synthesis of which dicarboxylic acids are used.

11. The composition according to claim 1, wherein the polymers prepared by polycondensation represent polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphtalate (PEN) and combinations thereof.

12. The composition according to claim 1 , wherein the polymer base is selected from the polymers prepared by polycondensation.

13. The composition according to claim 12, wherein the polymer base c) is selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphtalate (PEN) and combinations thereof.

14. The composition according to claim 13, wherein the quantity of polyethylene terephthalate is from 20 to 100 wt.% calculated to total quantity of the polymer base.

15. The composition according to claim 13, wherein the quantity of polyethylene naphtalate is from 20 to 100 wt.% calculated to total quantity of the polymer base.

16. The composition according to any one of claims 9 to 15, wherein the indicated polymers are secondary polymer feed.

17. A method for preparing the composition of a concentrate, the method comprising the stages: i) Providing a mixture of the component a) compound, selected from organic acid dianhydrides, and combinations thereof; b) compound selected from bis-, tris- and tetrakis-oxazolines and combinations thereof; and c) polymer base;

18. The method according to claim 17, wherein the component a) of the composition is selected from aromatic acid dianhydrides and combinations thereof.

19. The method according to claim 18, wherein the component a) is selected from pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride

(BPDA), oxydiphthalic dianhydride (ODPDA), and combinations thereof.

20. The method according to claim 17, wherein the component b) is selected from bis- oxazolines with aromatic fragments.

21. The method according to claim 20, wherein the aromatic fragment is selected from C5-C10-aryl or C5-C10-heteroaryl.

22. The method according to claim 21, wherein the component b) is selected from 1,3 (l,4)-phenylene-bis-oxazoline (PBO), 3,3 '(3,4';3,5')- naphthylene-bis-oxazoline (NBO), 4,4'(3,3';3,4';3,5^,)-di-phenylene-bis-oxazoline (DPBO), and combinations thereof.

23. The method according to claim 17, wherein the mass ratio of the components a) and b) is from 3: 1 to 1 :3, preferably from 2: 1 to 1 :2.

24. The method according to claim 17, wherein the mass ratio of the components a) and b) is from 5 : 1 to 1 ,5: 1, most preferable from 3 : 1 to 2: 1.

25. The method according to claim 17, wherein the component c) polymer base is selected from the polymers prepared by polycondensation.

26. The method according to claim 17, wherein the polymer base is selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphtalate (PEN) and combinations thereof.

27. The method according to claim 26, wherein the quantity of polyethylene terephthalate is from 20 to 100 wt. % calculated to total quantity of the polymer base.

28. The method according to claim 26, wherein the quantity of polyethylene naphtalate is from 20 to 100 wt. % calculated to total quantity of the polymer base.

29. The method according to claim 17, wherein the component c) is secondary polymer feed.

30. The method according to claim 17, wherein the component c) is preliminary dried.

31. The method according to claim 17, wherein the component c) is preliminary grind to particle size from 0,05 mm to 5 mm.

32. The method according to claim 17, wherein ii) mixing is occurred in high speed mixer.

33. The method according to claim 17, wherein the mixing speed is from 1000 to 5000 rpm, preferably from 1500 to 4000, most preferably 3000 rpm.

34. The method according to claim 17, wherein the mixing time range from 2 to 10 minutes, more preferably from 2.2 to 5 minutes.

35. The method according to claim 17, wherein mixing temperature is from 30 to 200°C, more preferable from 45 to 150 °C, most preferable from 70 to 135 °C.

36. A composition of a concentrate for increasing a viscosity of a polymer prepared by polycondensation prepared according to any one of claims 17 to 35.

37. A method of increasing viscosity of the polymer prepared by polycondensation comprising the stages: i) adding of a feed polymer into an extruder; ii) adding of a composition for increase a polymer viscosity, the composition comprising: a) compound, selected from organic acid dianhydrides, and mixtures thereof; b) compound selected from bis-, tris-, and tetrakis-oxazolines and mixtures thereof; and c) polymer base; wherein the mass ratio of the indicated components a) and b) is from 5: 1 to

1 :5; iii) extruding of the thus obtained mixture to obtain a polymer product.

38. The method according to claim 37, wherein the mass ratio of the components a) and b) is from 3: 1 to 1 : 1 , preferably from 2: 1 to 1 :2.

39. The method according to claim 37, wherein the mass ratio of the components a) and b) is from 5 : 1 to 1.5: 1, more preferably from 3:1 to 2 : 1.

40. The method according to claim 37, wherein the polymer presents polyester, more preferably is selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphtalate (PEN) and combinations thereof.

41. The method according to claim 37, wherein polymer base c) added on the stage ii) represents a polymer prepared from comonomer identical to the comonomer of polymer feed added on the stage i).

42. Use of the composition of a concentrate according to any one of claims 1 to 16 for increasing polymer viscosity.

43. The use according to the claim 42, wherein the polymer represents polyester selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphtalate (PEN) and combinations thereof.

44. Polymer product prepared using the composition according to any of claims 1 to 16.

45. Moulded article prepared from the polymer product according to claim 44.