WO2024251389A1

WO2024251389A1 - Plasticizers for polyamide

Info

Publication number: WO2024251389A1
Application number: PCT/EP2024/025173
Authority: WO
Inventors: Jelle CORNELUS; Arnaud Verraes; José VANHEULE
Original assignee: PROVIRON HOLDING NV
Current assignee: PROVIRON HOLDING NV
Priority date: 2023-06-07
Filing date: 2024-05-31
Publication date: 2024-12-12
Anticipated expiration: 2025-12-07

Abstract

The present invention relates to the use of N, N di-hydroxy-isopropyl benzene sulfonamide as plasticizer in polyamide compositions. According to a preferred embodiment, this plasticizer can be used in a weight amount higher than 5 %, more preferably higher than 15 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide. More in particular, the invention relates to the use of this compound as plasticizer in polyamide compositions, comprising polyamide 6 and/or polyamide 11. The invention also relates to polyamide compositions comprising this sulfonamide compound as plasticizers.

Description

Title: Plasticizers for polyamide

Description

The present invention relates to plasticizers for use in polyamide.

More in particular, the present invention relates to the use of N,N di-hydroxy isopropyl-benzene-sulfonamide as plasticizer in polyamide compositions.

In a preferred embodiment, the amount of plasticizer in the polyamide composition is higher than 5 %, expressed as weight percentage of plasticizer over the composition comprising the plasticizer and the polyamide.

The invention relates as well to compositions comprising polyamides and the plasticizer as mentioned. Background of the invention

It is known that benzene-sulfonamide compounds can be used as plasticizers in polyamide compositions.

Examples of these plasticizers are amongst others described in the international patent application published on April 9, 1998, under number WO 98/14513, held by UCB, S.A., Avenue Louise 326, Brussels, Belgium.

The plasticizers described in this patent application and tested in polyamide compositions all relate to primary benzene-sulfonamide compounds, except for the specific (di)-alkoxy benzene-sulfonamide compound(s), described on page 12 of this application. More in particular, the following compounds are described: on the one hand, N-ethyl-N (2-hydroxyethyl) benzene sulfonamide (indicated as AU) and on the other hand N, N, di- (2-hydroxyethyl) benzene sulfonamide (indicated as AT).

Both these secondary benzene sulfonamide plasticizers are described in this patent application as comparative examples, listed in table I on page 11. Reference is made to the sentence under this table 'Dans le tableau 1, les plastifiants marques (*) sont donnees a titre de comparaison’.

Both these compounds AU and AT are marked with such marking sign (*) and so are to be regarded as comparative examples.

On page 12, lines 17-18 again, it is noted that the plasticizing properties of both these comparative compounds are unsatisfactory, as is demonstrated in the tests provided by this patent application.

On table II on page 13 of this patent application the results are described of the use of both these compounds in a specific polyamide, namely PA- 12, in amounts ranging from 5 to 15 %. The conclusion is that both these compounds "ont des proprietes plastifiantes nettement moins bonnes que 1’AS, qui repond a 1’invention ».

Thus, the disclosure of the use of secondary benzene-sulfonamide plasticizers in polyamide in this patent application is limited to two specific compounds in a quite specific polyamide, namely PA-12, and in an amount of 15 % or less.

The tests and examples of this application relate to the use of plasticizers in an amount up to maximum 15 % in polyamides. The reason why the amount cannot be higher, is indicated on page. 21, lines 3-4: 'le module chute de 2/3 de sa Valeur en presence de 15 % de plastifiant.’

So, the teaching of this application comprises a clear advice against the use of secondary benzene-sulfonamides as plasticizers in polyamides, more in particular against the use of higher amounts of these plasticizers in polyamide compositions.

The US patent application, published as US 2016/0325147 Al by Acushnet Company, MA, USA, on November 10, 2016, describes the use of secondary benzene sulfonamides, more in particular N-butyl-N-dodecyl-benzene-sulfonamide (BDBSA) and N, N-dimethylbenzene-sulfonamide (DMBSA) as plasticizers in polyamide.

The article entitled "The effect of benzene-sulfonamide plasticizers on the glass transition temperature of an amorphous aliphatic polyamide", from Ph. De Groote e.a., published in Polymer International 51/40-49 (2001) by the Society of Chemical Industry, describes the same compounds as mentioned hereinabove as plasticizers in polyamide. The Japanese patent application, published on July 22, 2004, under nr.

2004204104 by Toray Ind. Inc., describes the use of N, N’-dibutyl benzenesulfonamide as plasticizer in polyamides.

The Chinese patent application, published on 17 September 2014 under Nr. CN 104046011 (A) by Anhui Anlan Mould Co., Ltd, discloses the use of 2 to 3 parts of N, N’- dimethyl benzene-sulfonamide as plasticizer is a nylon composite composition.

There remains a general need for compounds, usable as plasticizers in polyamides. More in particular, there remains a need for compounds, usable as plasticizers in polyamide compositions, that can be used in the high amounts or concentrations as above mentioned, without negative or detrimental effects.

More in particular, there remains a clear need with users for plasticizers for use in polyamides in amounts higher than 5 %, more in particular higher than 15 %, and more preferably higher than 25 %. Under such conditions, the plasticizers should not leach out at such high concentrations. Such leaching out inevitably gives rise to a marked age hardening of the compositions wherein such amounts of plasticizers are incorporated upon their manufacture.

Summary of the invention

The aim of the present invention is to offer a solution to the abovementioned and other disadvantages in that it comprises the use of N, N di-hydroxy-isopropyl benzene-sulfonamide as plasticizer in polyamide.

According to a preferred embodiment, the weight amount of the N, N di-hydroxy- isopropyl benzene-sulfonamide as plasticizer in the polyamide composition is higher than 5 %, expressed as weight % of plasticizer relative to the composition comprising the plasticizer and the polyamide. The present invention relates as well to a composition comprising polyamide and

N, N di-hydroxy-isopropyl benzene-sulfonamide as plasticizer.

According to a preferred embodiment, the weight amount of this plasticizer in the composition is higher than 5 %, expressed as weight percent (%) of plasticizer relative to the composition comprising the plasticizer and the polyamide.

More in particular the invention relates to the use and the compositions as set forth in the appended claims. In the context of the present invention, a primary benzene-sulfonamide compound should be understood as a benzene-sulfonamide on the basis of a primary aminegroup, so still comprising a free H-atom in the sulfonamide-bond; a secondary benzene-sulfonamide compound should be understood as a benzene-sulfonamide on the basis of a secondary amine-group, so without a free H-atom in the sulfonamide bond.

Description of the invention

As indicated above, the present invention relates to the use of N, N di-hydroxy- isopropyl benzene-sulfonamide as plasticizer in polyamide.

According to a preferred embodiment, the weight amount of N, N di-hydroxy- isopropyl benzene-sulfonamide is higher than 5 %, expressed as weight % of the plasticizer relative to the weight of the polyamide and the plasticizer. According to a preferred embodiment of the invention, the weight-amount of plasticizer is higher than 15 %, preferably higher than 25 %, , expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide. According to a further preferred embodiment of the invention, the weight-amount of plasticizer is comprised between 5 and 45 %, preferably between 15 and 40 %, more preferably between 25 and 40 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

According to a further preferred embodiment of the invention, the polyamide comprises polyamide 6 and/or polyamide 11.

According to a further preferred embodiment of the invention, the polyamide is chosen out of any of the following polyamides, or wherein the polyamide comprises two or more of the following polyamides: polyamide-6, polyamide-6,6, polyamide-4,6, polyamide-6,9, polyamide-6,10, polyamide-6,12, polyamide 11, polyamide 12, and the polyamide MXD-6.

As indicated supra, the present invention also relates to a composition comprising a polyamide and N, N di-hydroxy-isopropyl benzene-sulfonamide as plasticizer.

According to a preferred embodiment, the weight amount of N, N di-hydroxy- isopropyl benzene-sulfonamide compound is higher than 5 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

According to a preferred embodiment of the invention, the amount of plasticizer is higher than 15 %, preferably higher than 25 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide. According to a further preferred embodiment of the invention, the amount of plasticizer is between 5 and 45 %, preferably between 15 and 40 %, more preferably between 25 and 40 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide. According to a further preferred embodiment of the invention, the polyamide comprises either polyamide 6 and/or polyamide 11. According to a further preferred embodiment of the invention, the polyamide is chosen out of any of the following polyamides, or wherein the polyamide comprises two or more of the following polyamides: polyamide-6, polyamide-6,6, polyamide-4,6, polyamide-6,9, polyamide-6,10, polyamide-6, 12, polyamide 11, polyamide 12, and the polyamide MXD-6.

Polyamides

In the context of the present invention, the following should be understood with respect to the various types of polyamides as cited in the present document: PA 6: polyamide prepared by a ring-opening polymerization of e-caprolactam

PA 6,6: polyamide prepared by polymerization of 1,6-hexane-diamine and adipic acid

PA 4,6: polyamide prepared by polymerization of 1,4-butane-diamine and adipic acid PA 6,9: polyamide prepared by polymerization of 1,6-hexane-diamine and azelainic acid

PA 6,10: polyamide prepared by polymerization of 1,6-hexane-diamine and sebacic acid

PA 6,12: polyamide prepared by polymerization of 1,6-hexane-diamine and 1,12- dodecane di-acid

PA 11: polyamide prepared by polymerization of 11-aminoundecaanic acid PA 12: polyamide prepared by polymerization of 12-aminododecanic acid or laurolactam Secondary benzene-sulfonamide

According to the invention, the secondary benzene-sulfonamide is N, N di-hydroxy isopropyl benzene-sulfonamide.

(hereinafter in short referred to as DIPBSA). The structural formula of this compound is set forth hereinafter:

This compound can be prepared according to the following synthesis.

DIPBSA can be prepared by synthesis of on the one hand di-hydroxy isopropylamine with on the other hand benzene-sulfonyl-chloride.

Structural formula of di-hydroxy isopropylamine:

Structural formula of benzene-sulfonyl-chloride:

Example of a preparation method

2 743 g of di-hydroxy isopropylamine (20.6 mol) and 901 g of water are introduced into a reactor, followed by stirring, followed by heating up until approximately 60 °C.

As reactor, use is being made of a 10 liter, double-walled, glass reactor, equipped with an oil bath, a mechanical stirrer and a thermo-couple, included in a glass tube with silicon oil, a pH-meter, a vertical water cooler, a nitrogen inlet by means of a dip-tube and a vacuum membrane pump.

In order to feed the reagents to the reactor, use is being made of two peristaltic pumps.

Hereupon, 3 551 g of benzene-sulfonyl-chloride (20.1 mol) is added over a time interval of 4 h 15 minutes.

The temperatures then rizes to 70 a 80 °C as a result of the exothermic reaction. Whilst introducing the benzene-sulfonyl-chloride reagent, 3 216 g 25% NaOH (20.1 mol) is added in order to neutralize the hydrochloric acid, resulting from the ongoing reaction.

Hereupon the stirring is terminated and the mixture is decanted for approx. 2 hr. 4406 g of aqueous salty phase is separated and removed.

Hereupon the organic phase is washed twice with approx. 1 100 g of water, followed by drying up until approx. 124 °C and 33 mbara.

The resulting end-product was 4946 g, characterized by a melting point of 94 °C.

First series of application tests

A number of application tests have been performed in order to review the effects of the use of a secondary sulfonamide, more in particular DIPBSA, in a polyamide composition, more in particular polyamide 6 injection grade (this is the grade suitable for injection molding), more in particular for higher amounts of plasticizer.

As comparative example, the usual primary sulfonamide plasticizer is used, namely butyl-benzene-sulfonamide (BBSA).

Extrusion tests

A first series of tests relates to the incorporation of (higher amounts) of plasticizer in polyamide, more in particular in polyamide 6.

To this end, use has been made of a 26 mm co-rotating double extrusion screw, marketed under the brand name Labtech by Labtech S.r.L., Sorisole, Italy.

This extrusion screw comprises all in total 10 zones, starting with zone 0 (Z0), wherein upon the influence of gravimetric forces polyamide granules are introduced into the extruder, and ending in an extrusion die, through which the melted mass is extruded and molded in the form of threads. These threads are further cooled in a cooling bath and cut.

1) Extrusion of polyamide 6 granules of non-plasticized polyamide 6 are introduced in zone 0 and throughout the zones of the extruder pressed until and through the extrusion die-head. The temperature in the zones is set at 260 °C. At lower temperatures, the granules are not fully melted. The throughput of polyamide amounted to 10 kg/hr.

The speed of the extrusion screw amounted to 170 rpm.

The pressure throughout the die head amounted to 5 up to 8 bar.

These operating parameters appear to be optimum for the extrusion of nonplasticized polyamide 6.

2) Extrusion of polyamide 6, comprising 20 % of BBSA

20 % of BBSA as plasticizer was added to polyamide 6. Given the liquid character of this plasticizer, it was injected in Zone 0 of the extruder. The operating parameters of the extruder were as follows.

The temperature in the various zones of the extruder was set at 230 °C.

The throughput of polyamide was set at 8 kg/hr.

The throughput of plasticizer was set at 2 kg/hr.

The speed of the extrusion screw amounted to 170 rpm.

The pressure throughout the die head amounted to 6 bar.

This plasticizer, under the a.m. operating conditions, appears to generate vapors or fumes upon contact with the extruder at 230 °C.

However, under these operating conditions, the polymer was not fully melted as it passed through the extruder by pressure, resulting in an inhomogeneous extruded mass. It appeared to be impossible to form threads for the production of granules. Because of this, the material as a whole was taken out of the extruder and separately processed up to granules. ) Extrusion of polyamide 6, comprising 20 % of DIPBSA

20 % of DIPBSA as plasticizer was added to polyamide 6.

Prior hereto, the plasticizer was shredded to 12 mm granules and was sideways added to zone 3 of the extruder. The plasticizer could be handled in a smooth and easy manner and was melted together with the polyamide and pressed throughout the extruder under the operating parameters of the extruder as set forth hereinafter.

The temperature in the various zones of the extruder was set at 260 °C in zones Z1 up to and including Z5, decreasing till 240 °C in Zones Z8 up to and including Z10, and the die head.

The throughput of polyamide was set at 8 kg/hr.

The throughput of plasticizer was set at 2 kg/hr.

The speed of the extrusion screw amounted to 170 rpm.

The pressure throughout the die head amounted to 11 bar. ) Extrusion of polyamide 6, comprising 40 % of DIPBSA

40 % of DIPBSA as plasticizer was added to polyamide 6.

Initially, the extrusion-operating parameters as set forth above under 3) were used.

However, in that case, the polymer threads became slightly milky or opaque. In order to avoid same, the temperatures in the zones 7, 8, 9 and 10 and the die head were slightly increased, until the set parameters as indicated hereinafter were reached.

In this manner, the plasticizer could be processed and pressed through the extruder and die head without problems under the operating conditions as set forth hereinafter.

The set temperature in the various zones of the extruder amounted to 260 °C in zones Z1 up to and including Z5, and 250 °C in Zones Z6 up to and including Z10, and the die head.

The throughput of polyamide was set at 8 kg/hr.

The throughput of plasticizer was set at 2 kg/hr.

The speed of the extrusion screw amounted to 170 rpm. The pressure throughout the die head amounted to 5 bar.

The results of the tests as described hereinabove were that DIPBSA could easily be incorporated in PA-6 in amounts up to 40 %, without generating any vapors or fumes.

Injection molding tests (mechanical properties)

The extruded polyamide-plasticizer compositions comprise approx. 2 000 ppm of remaining water after drying and before injection molding.

The extruded granules therefore were dried during 7 hours at 80 °C in an air dryer. Hereupon the samples were injection molded according to the process set forth in ISO 527-2 (2012).

Injection molding of the samples

1) Injection molding of polyamide 6

The operating parameters were as follows:

- temperature throughout the injection molding extruder: increasing from 235 until 255 °C.

- temperature at the nozzle orifice: 260 °C.

- pressure: 1 032 bar.

The above figures are characteristic for the usual injection molding of polyamide. The so produced samples show a good visual aspect: the edges are well-defined and the material is homogeneous.

2) Injection molding of polyamide 6, comprising 20 % of BBSA Operating parameters as set forth above under 1).

However, the so produced samples were quite greasy, probably resulting from the migration and sweating out of the plasticizer to the surface. Droplets, probably from the plasticizer, were visible for the eye. 3) Injection molding of polyamide 6, comprising 20 % of DIPBSA

The operating parameters were as indicated under 1) or 2), but optimized for this plasticizer:

- temperature throughout the injection molding extruder: 255 to 250 °C.

- temperature at the nozzle orifice: 240 °C.

- pressure: 67 bar.

The so produced samples show a good visual aspect: the edges are well- defined. The surface of the samples appears to be more matte as compared to other plasticized polyamide samples.

4) Injection molding of polyamide 6, comprising 40 % of DIPBSA

The operating parameters were as indicated under 3), but optimized for this plasticizer:

- temperature throughout the injection molding extruder: 235 to 240 °C.

- temperature at the nozzle orifice: 230 °C.

- pressure: 39 bar.

Aging

As a next test, the abovementioned polyamide-plasticizer compositions were subjected to an aging-test.

The aging of the samples was performed in an oven during one week at 100°C. The mechanical test was performed according to the standard ISO 527-2 (2012). For the execution of these mechanical tests use was made of an Instron 5982 broke-test apparatus, comprising manual clamps.

Before executing the tests, the samples were conditioned during at least 24 hr at 23 °C, 50 % relative humidity.

The following physical properties were determined according to this method:

- modulus (elasticity modulus measured between 0.05 and 0.25 % pulling power (1 mm/min); Strain at break: prolongation at break, calculated by registering the change in grip (distance by break - initial distance)/ initial distance*100 (at an initial length of 115 mm)

The conclusion that can be drawn from the above measurements and test results is as follows. The mechanical properties of the polyamide compositions plasticized with DIPBSA are somewhat less improved compared to the polyamide compositions plasticized with BBSA, but the mechanical properties of the DIPBSA plasticized polyamide composition are much better kept at aging.

These evaluations and tests as performed clearly demonstrate that the secondary benzene-sulfonamides according to the invention can be used as plasticizers in polyamide 6, even at increased or higher amounts of plasticizer.

Second series of application tests

A second series of application tests has been performed in order to review the effects of the use of a secondary sulfonamide, more in particular DIPBSA, in a polyamide composition, more in particular polyamide 11 injection grade (this is the grade suitable for injection molding). The purpose of these tests was to compare the performance of the secondary sulfonamide according to the invention, this is N, N di-hydroxy-isopropyl benzene sulfonamide, with other secondary benzene sulfonamides, known as such, and disclosed in the prior art documents cited under the heading "Background of the invention" of the present application.

Butyl dodecyl benzene-sulfonamide could not be used as comparative secondary benzene-sulfonamide by the inventors, as one of the reagents required to prepare this plasticizer, namely, N-butyl N-dodecyl amine, could not be sourced on the market.

Further, two compounds could be used as closest prior art to the N, N di hydroxyisopropyl benzene sulfonamides according to the invention, namely:

- di-methyl benzene sulfonamide (DMBSA);

- di-butyl benzene sulfonamide (DBBSA).

On the basis of its structure alone, the dimethylamine required for the synthesis of DMBSA clearly is a relatively volatile compound compared to the dibutylamine required for the synthesis of DBBSA.

In view of the above, the inventors have synthesized the DBBSA plasticizer and the properties of this compound were measured and compared to the properties of the plasticizer according to the invention, namely the N,N di-hydroxy-isopropyl benzene sulfonamide.

The properties have been tested in PA 11 as polyamide, and taking into account an amount of 14 % of plasticizer, expressed in weight % of plasticizer, relative to the weight of the composition comprising both the plasticizer and the polyamide.

The test results are summarized in the following table:

From the above table, it appears that the N,N di-hydroxy isopropyl benzenesulfonamide compound, as compared to DBBSA, yields much better results for all of the measured criteria or parameters:

DIPBSA yields, as compared to DBBSA, a lower modulus;

DIPBSA yields, as compared to DBBSA, a higher strain at break;

DIPBSA keeps, as compared to DBBSA, both improved properties also upon aging (7 days at 100 °C). The above features could not be expected from any of the prior art documents cited earlier under the heading "Background of the invention".

These unexpected, improved properties ensure that the secondary benzene sulfonamide according to the invention, is highly suitable as plasticizer for polyamide compositions, in particular in the higher weight amounts as indicated relative to the weight of the polyamide and plasticizer.

The above more in particular applies to the use as plasticizer of DIPBSA in PA 6, PA 11 or any combination of polyamides comprising either PA6 and/or PA11. The above more in particular applies to the use of such plasticizer in the polyamides as indicated, in weight amounts of 5, preferably 15, more preferably 25 %, relative to the weight of the plasticizer and the polyamide.

In a broader perspective, the present invention is directed not only to the use of the specific compound listed above, this is N, N di-hydroxy-isopropyl benzenesulfonamide, as plasticizer in polyamides, but to the use of the broader scope of compounds denoted by N, N di-hydroxy-alkyl benzene-sulfonamides, with the alkyl moiety containing at least 3 carbon atoms, as plasticizer in polyamides. According to a preferred embodiment, the weight amount of N, N di-hydroxy-alkyl benzene-sulfonamide compound is higher than 5 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

According to a preferred embodiment, the weight amount of such broader class of benzene-sulfonamides used as plasticizers is higher than 15 %, preferably higher than 25 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

Likewise, in a broader perspective, the invention relates to a composition comprising polyamide and N, N di-hydroxy-alkyl benzene-sulfonamide with an alkyl moiety containing at least 3 carbon atoms, as plasticizer.

According to a preferred embodiment, the weight amount of this broader class of plasticizers in the polyamide composition is higher than 5 %, expressed as weight percent (%) of plasticizer relative to the composition comprising the plasticizer and the polyamide.

According to a further preferred embodiment, the weight amount of the plasticizer is higher than 15 %, preferably higher than 25 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide. The preferred embodiments set forth above with respect to the use as plasticizer in polyamides, and the compositions comprising polyamides and N, N di-hydroxy- isopropyl benzene-sulfonamide are likewise applicable to the use as plasticizer in polyamides and the compositions comprising the broader class of N, N di-hydroxy- alkyl benzene-sulfonamide compounds.

Claims

1. Use of N, N di-hydroxy-isopropyl benzene-sulfonamide as plasticizer in polyamide.

2. Use according to claim 1, characterized in that the weight-amount of the plasticizer is higher than 5 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

3. Use according to claim 2, characterized in that the weight-amount of plasticizer is higher than 15 %, preferably higher than 25 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

4. Use according to claim 1, characterized in that the weight-amount of plasticizer is comprised between 5 and 45 %, preferably between 15 and 40 %, more preferably between 25 and 40 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

5. Use according to any of the preceding claims, wherein the polyamide comprises polyamide 6 and/or polyamide 11.

6. Use according to any of the preceding claims, wherein the polyamide is chosen out of any of the following polyamides, or wherein the polyamide comprises two or more of the following polyamides: polyamide-6, polyamide-6,6, polyamide-4,6, polyamide-6,9, polyamide- 6,10, polyamide-6, 12, polyamide 11, polyamide 12, and the polyamide MXD-6.

7. Composition comprising polyamide and N, N di-hydroxy-isopropyl benzene-sulfonamide as plasticizer.

8. Composition according to claim 7, characterized in that the weight-amount of the plasticizer is higher than 5 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

9. Composition according to claim 8, wherein the amount of plasticizer is higher than 15 %, preferably higher than 25 %, expressed as weight % of plasticizer over the composition comprising the plasticizer and the polyamide.

10. Composition according to claim 7, wherein the amount of plasticizer is between 5 and 45 %, preferably between 15 and 40 %, more preferably between 25 and 40 %, expressed as weight % of plasticizer over the

11. Composition according to any of the claims 7-10, wherein the polyamide comprises either polyamide 6 and/or polyamide 11.

12. Composition according to any of the claims 7-10, wherein the polyamide is chosen out of any of the following polyamides, or wherein the polyamide comprises two or more of the following polyamides: polyamide-6, polyamide-6,6, polyamide-4,6, polyamide-6,9, polyamide- 6,10, polyamide-6, 12, polyamide 11, polyamide 12, and the polyamide MXD-6.