AU699659B2

AU699659B2 - Flexible translucent polyamide-based composition, process for its conversion and articles obtained from this composition

Info

Publication number: AU699659B2
Application number: AU37988/95A
Authority: AU
Inventors: Alain Bouilloux; Christelle Guibouin; Beatrice Ladouce; Thibaut Montanari; Patrice Perret
Original assignee: Elf Atochem SA
Current assignee: Arkema France SA
Priority date: 1994-11-22
Filing date: 1995-11-21
Publication date: 1998-12-10
Anticipated expiration: 2015-11-21
Also published as: DE69515004T2; JPH08225740A; KR100388325B1; NO954657D0; FI955602A0; DE69515004D1; NO954657L; NO309485B1; FR2727124A1; ES2143589T3; JP4134338B2; AU3798895A; PT716126E; CA2163398A1; FR2727124B1; EP0716126B1; FI111852B; EP0716126A1; GR3032921T3; ATE189691T1

Abstract

A translucent, flexible compsn. contains: (A) 50-95 wt.% of (1) a polyamide resin (PA) with light transmission at 700 nm above 15% (above 30%) (1 mm plate), (2) additives, e.g. stabilisers, demoulding agents, lubricants, crystallisation accelerators, pigments, dyes, organic and/or mineral fillers, and antioxidants, and (3) 0-50% (less than 20%), w.r.t. (A), of a plasticiser; and (B) 50-5% (10-40%) of (a) a terpolymer of ethylene, an alkyl (meth)acrylate and an anhydride of an unsatd. dicarboxylic acid, and (b) an ethylene/alkyl (meth)acrylate copolymer, in ratio of (b)/(a) or 1/30-2 (not above 2/3). The modulus of flexing (ISO 178) of the compsn. is <2/3 (<1/3) of the modulus of flexing of PA and below <750 MPa (<500 MPa).

Description

2 t'flU000 2w"IP Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: 99 9 9 .9 99 9 9 99 9999 99 99 9 .9 9999 99 99 9 9 9 9 99 .9 9 .99 9999 9 99 99 9 9- 999999 9 9 999999 9 9 9 9 99999 9 9 99 9 99 9 .9 Invention Title, FLEXIBLE TRANSLUCENT POLYAMIDE-BASED COMPOSITION, PROCESS FOR ITS CONVERSION AND ARTICLES OBTAINED FROM THIS COMPOSITION The following statement is a full description of this Invention, Including the best method of performing It known to us FLEXIBLE TRANSLUCENT POLYAMIDE-BASED COMPOSITION, PROCESS FOR ITS CONVERSION AND ARTICLES OBTAINED FROM THIS COMPOSITION The subject of the present invention is a flexible translucent polyamide-based composition.

Compositions with a matrix containing polyamide and ethylene polymers are already known for their impact strength.

In particular, EP 096,264 describes a material with a high impact strength containing: a thermoplastic polyamide having a relative viscosity of 2.5 to 5, and from 5 to 60 weight with respect to of an uncrosslinked terpolymer consisting of: 55 to 79.5 weight of ethylene, 20 to 40 weight of at least one primary or secondary alkyl (meth)acrylate, and 0.5 to 8 weight of a functionally acidic monomer (for example, maleic anhydride).

EP 218,665 describes compositions containing from 50 to 95 weight of at least one polyamide resin and from 5 to 50 weight of at least one ethylene polymer I containing from 0.9 to 16 mol of units derived from maleic anhydride and/or from at least one alkyl acrylate 25 or methacrylate in which the alkyl group has from 1 to 6 carbon atoms. The said ethyle<,e polymer is present in the form of a mixture of ethylene-alkyl (meth)acrylate copolymer and of ethylene-maleic anhydride-alkyl (meth)acrylate terpolymer the ratio by 30 weight being between 1/3 and 3.

EP-A-072,480, which describes an impact-resistant composition comprising ftom 50 to 90 weight of polyamide, from 1 to 45 weight of an ionomeric ethylene resin and from 0.5 to 40 weight of an elastomeric ethylene copolymer, is also known.

Finally, Patent US 3,373,223 describes a polymer alloy essentially composed of 25 to 90 weight of polyolefin, 5 to 70 weight of polyamide and 1 to weight of an ethylene-(meth)acrylic acid copolymer.

~--31L 1 L II I -=rzrr_~ 2 However, these compositions, which have an improved impact strength in comparison with the polyamide matrix employed alone, require high processing temperatures often greater than 270°C and are not generally simultaneously translucent and flexible.

A translucent composition based on polyamide resin, which is very flexible and easy to process, in particular by extrusion, has now been found, which composition is characterized in that it comprises: from 50 weight to 95 weight 1) of at least one polyamide resin the light transmission of which at 700 nm is greater than 15% and preferably greater than 30% (through a sheet with a thickness of 1 mm), 2) of various additives (IV) such as stabilizers, mould-release agents, lubricants, crystallization accelerators, pigments, organic and/or inorganic fillers or dyes, or antioxidizing agents, 3) optionally of at least one plasticizing agent representing from 0 to 50 weight of and preferably less than 20 weight of from 5 weight to 50 weight and preferably from 10 to 40 weight of at least one ethylene-alkyl (meth)acrylate-unsaturated dicarboxylic acid anhydride terpolymer (II), f*o* of at least one ethylene-alkyl (meth)acrylate copolymer (III) with 1/30 s s 2 and preferably s 2/3 a 30 and such that its flexural modulus, measured according to ISO standard 178, is less than or equal to 2/3 of the flexural modulus of the PA resin alone and is strictly less than 750 MPa, and advantageously less than "or equal to 1/3 of the flexural modulus of the PA resin alone and is strictly less than 500 MPa.

According to the present invention, the terpolymer (II) comprises from 77 mol to 99.2 mol of at least one unit derived from ethylene, from 0 mol to mol of at least one unit derived from alkyl (meth)- 3acrylate(s) and from 0.8 mol to 3 mol of at least one unit derived from unsaturated dicarboxylic acid anhydride(s), and preferably of at least one maleic anhydride derivative, and has a melt index of between 0.1 and 400 g/10 min, measured according to NFT standard 51- 016 (190 0 C/load of 2.16 kg). For reasons of simplification, the term "terpolymer" is employed throughout the text, even in the cases where (II) does not contain any unit derived from alkyl (meth)acrylate(s).

According to the present invention, the copolymer (III) comprises at least 78 mol of units derived from ethylene and up to 22 mol of at least one unit derived from alkyl (meth)acrylate(s) and has a melt index of between 0.1 and 400 g/10 min, measured according to NFT standard 51-016 (1900C/load of 2.16 kg).

The alkyl groups of the alkyl acrylate or methacrylate taking part in the terpolymers (II) and/or in the copolymers (III) may be linear, branched or cyclic and aliphatic, cycloaliphatic and/or aromatic and may contain up to 10 carbon atoms.

Mention may be made, as illustrations of alkyl from acrylate or methacrylate from which the terpolymers (II) and/or the copolymers (III) derive, of, in particular, methyl acrylate, ethyl acrylate, n-butyl acrylate, S* 25 isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

I. Among these alkyl acrylates and methacrylates, ethyl acrylate n-butyl acrylate (BA) and methyl acrylate (MA) are very particularly preferred.

30 Mention may be made, as illustrations of unsaturated dicarboxylic acid anhydride from which the terpolymers (II) derive, of itaconic anhydride, citraconic S* anhydride, 2-methylmaleic anhydride, 2,3-dimethylmaleic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride and, preferably, maleic anhydride.

Polyamide resin according to the invention is understood to mean the polyamides or PAs which contain aliphatic units containing at least 7 carbon atoms and/or cycloaliphatic units and/or aromatic units.

4- Mention may be made of the resins obtained by polycondensation of one or a number of lactams or of a,wamino acids or by a substantially stoichiometric polycondensation of one or a number of aliphatic diamine(s) and of one or a number of aliphatic dicarboxylic acid(s). It is possible to use an excess of diamine, so as to obtain an excess of amine end groups with respect to the carboxyl end groups in the polyamide.

The lactams contain at least 7 carbon atoms and preferably at least 10. The preferred lactams are decalactam, undecalactam and dodecalactam.

The preferred a,w-amino acids are decanoic, 11-aminoundecanoic and 12-aminododecanoic acids.

The aliphatic diamines are a,o-diamines containing, between the end amino groups, at least 6 carbon atoms and preferably from 6 to 10. The carbon chain may be linear (polymethylenediamine) or branched. Preferred diamines are hexamethylenediamine (HMDA) and dodecamethylenediamine.

"The aliphatic dicarboxylic acids are a,wdicarboxylic acids having at least 5 carbon atoms (not including the carbon atoms of the carboxyl groups), and 0"°0 "preferably at least 6, in the linear or branched carbon chain. The preferred diacids are azelaic, sebacic and 1,12-dodecanoic acids.

Mention may be made, as illustrations of such PA 6" 0 resins, of: polyhexamethylene sebacamide (PA-6,10), polyhexamethylene dodecanediamide (PA-6,12), poly(undecanoamide) (PA-11), polylauryllactam (PA-12), °polydodecamethylene dodecanediamide (PA-12,12).

a o" The PAs have a number-average molecular mass 9i generally greater than or equal to 5,000. Their inherent viscosity (measured at 20 0 C for a 0.5 g sample in 100 g of meta-cresol) is generally greater than 0.7.

PA, within the meaning of the present invention, is also understood to mean mixtures of polymers containlu 5 ing at least 50 weight of the polyamides described above where the matrix phase consists of polyamide.

Mention may be made, as examples of mixtures, of mixtures of aliphatic polyamides and of semi-aromatic and/or amorphous polyamides, such as those described in EP 550,308, as well as PA/polyolefin mixtures and in particular those described in EP 342,066.

PA according to the invention is also understood to mean polyamide-based thermoplastic elastomers (TPE) which are block copolymers, also known as polyetheramides, the rigid sequences of which consist of polyamide and the crystallizable flexible sequences of which consist of polyether.

Mention may be made, among the plasticizing agents which may be incorporated in the compositions according to the invention, of, for example, butylbenzenesulphonamide (BBSA), ethylhexyl para-hydroxybenzoate (EHPB) or decahexyl para-hydroxybenzoate (DHPB).

In general, plasticizing agents have the disadvantage of exuding more or less rapidly (a few days to a few months) out of the polymeric material in which they are incorporated, thus resulting in a loss in mass and dimensional variation in material.

The compositions according to the invention which I 25 are plasticized, i.e. in which have the additional advantage, compared with polyamide-based compositions containing only plasticizer but containing neither terpolymer (II) nor copolymer (III), of having a similar flexibility for a lower level of plasticizer and thus for 0 30 reduced exudation and better dimensional stability.

The above compositions can be obtained in a known way by any technique for mixing the constituents in the Smolten state, such as, for example, extrusion or compounding using a single- or twin-screw extruder or a cokneader, or by any continuous or batch technique, such as, for example, using an internal mixer.

The present invention also relates to the processes for the conversion of the said compositions and to the articles obtained. The materials or articles -6 obtained, in particular pipes, films, tubing, sheets, fibres, and the like, are translucent and have good mechanical and chemical properties, such as good flexibility.

Among all the conventional conversion methods used in the thermoplastics industry which are suitable for the production of articles based on compositions according to the invention, mention will very particularly be made of extrusion techniques.

The materials obtained by extrusion from the compositions according to the invention, for example pipes, have a smooth surface condition; their transparency is therefore not disturbed by surface defects.

The extrudability of the compositions according to the invention during their conversion is significantly better than the extrudability of PA-based compositions which did not simultaneously contain terpolymer(s) (II) and copolymer(s) (III); in practice, this better extrudability may be reflected in reduced extrusion temperatures (of the order of approximately thirty degrees Celsius) with a similar behaviour of the molten product and with a similar final appearance of the pipe.

In the case of compositions based on plasticized 0 0 4 4PA, the expression "better extrudability" is 25 reflected in extrusion temperatures similar to those of

S

the plasticized PA containing neither terpolymer(s) (I) 000 !nor copolymer(s) (III).

0* The following examples illustrate the invention.

EXAMPLE 1 0 30 The extrusion is carried out, in a twin-screw extruder or in a co-kneader, in the form of rods which are then granulated, of a mixture comprising 70 weight of PA-Il plasticized to 12 weight o with BBSA, the inherent viscosity of which is between 1 and 1.2 and the melting temperature of which is between 176 and 183C 25 weight of ethylene-BA-maleic anhydride terpolymer with the molar composition 94.4/4.6/1 and with a melt index equal to 4.5 g/10 min, measured according to 7- NFT standard 51-016 (190 0 C/load of 2.16 kg), 5 weight of copolymer of ethylene and of MA with the molar composition 94.4/5.6 and with a melt index equal to 0.3 g/10 min, measured according to NFT standard 51-016 (190C/load of 2.16 kg).

The flexural modulus, the exudation and the translucency of the composition thus obtained are measured.

The flexural modulus is measured according to ISO standard 178; the flexural modulus of the corresponding PA alone is also given, by way of comparison.

The exudation is determined by the loss in weight undergone by a sample after 30 days in an air-ventilated oven at 120 0

C.

The translucency is determined by the light transmission at 700 nm through a sheet with a thickness of 1 mm. A light transmission greater than 15% is judged acceptable and particularly advantageous when it is greater than This composition is then extruded in the form of a 00 pipe with an internal diameter equal to 6 mm and with an external diameter equal to 8 mm using an extruder equipped 1 a) with a screw adapted to the extrusion of plasticized PA with a diameter of 60 mm and with a length/diameter ratio *i of 24 b) and with a die coated with chromium or nickel. The extrudability is determined by assessing the ease of processing during the extrusion of the pipe (behaviour of the molten mass, sizing of the diameter of the pipe, nonbreaking) and by measuring the maximum temperature of the curve of the extrusion temperatures necessary to obtain a pipe with a good appearance (smooth surface appearance) The extrudability is described as "poor" when the pipe has a poor surface appearance and/or the conversion process is poorly controlled and/or the temperature curve necessary to obtain a pipe with a good appearance is too high.

The results are combined in Table 1.

EXAMPLES 2.a to 2.c (comparative) By way of comparison, pipes with identical

I

r -1 8 dimensions to that described in Example 1 are extruded from PA-11 a) containing a different level of plasticizer (28weight the inherent viscosity of which is between 1.1 and 1.4 and the melting temperature of which is between 170 and 176 0 C (Example 2.a) b) containing the same level of plasticizer as that described in Example 1 but the inherent viscosity of which is between 1.4 and 1.6 (Example 2.b).

c) not containing plasticizer and the inherent viscosity of which is between 1.3 and 1.6 and the melting temperature of which is between 183 and 187 0 C (Example 2.c).

The flexural modulus, exudation and translucency of the PA-11 samples thus extruded and the extrudability of the pipes obtained are measured. The results are combined in Table 1.

EXAMPLES 2.d to 2.f (comparative) By way of comparison, the followi, g mixtures are extruded and then shaped as pipes with the same dimensions as that described in Example 1: o d) a mixture (Example 2.d) comprising 70 weight of the same PA-11 as that in Example 1 (plasticized to 12 weight with BBSA) 30 weight of ethylene-BA-maleic anhydride terpolymer with the molar composition 94.4/4.6/1 and with l"0. a melt index equal to 4.5 g/10 min, measured according to I NFT standard 51-016 (1900C/load of 2.16 kg), e) a mixture (Example 2.e) comprising 30 70 weight of the same PA-11 as that in Example 1 (plasticized to 12 weight with BBSA) 30 weight of ethylene-BA-maleic anhydride I terpolymer with the molar composition 88.2/11.5/0.3 and a melt index equal to 7 g/10 min, measured according to NFT standard 51-016 (1900C/load of 2.16 kg), f) a mixture (Example 2.f) comprising 70 weight of the same PA-11 as that in Example 1 (plasticized to 12 weight with BBSA) 30 weight of ethylene-maleic anhydride A I i I~l^arnilDF3~ ~~~,~~wrunmnrx~ 9 copolymer with the molar composition 94.4/5.6.

The flexural modulus, exudation and translucency of the samples based on PA-11 thus extruded and the extrudability of the pipes obtained are measured. The results are combined in Table 1.

EXAMPLE 3 A mixture comprising 70 weight of PA-12 plasticized to 12 weight with BBSA and the inherent viscosity of which is between 1.3 and 1.7 and the melting temperature of which is between 168 and 174°C 25 weight of ethylene-BA-maleic anhydride terpolymer with the molar composition 94.4/4.6/1 and with a melt index equal to 4.5 g/10 min, measured according to NFT standard 51-016 (1900C/load of 2.16 kg), 5 weight of copolymer of ethylene and of MA with the molar composition 94.4/5.6 is extruded and then shaped as a pipe with the same dimensions as that described in Example 1.

The flexural modulus, exudation and translucency of the sample based on PA-12 thus extruded and the .9 extrudability of the pipe obtained are measured. The .0 results are combined in Table 1.

EXAMPLE 4 (comparative) 25 By way of comparison, a mixture comprising 75 weight of PA-12 with the same characteristics as that in Example 3 (containing the same level of

BBSA)

25 weight of ethylene-propylene-maleic 30 anhydride elastomeric copolymer mEPR comprising from 0.4 to 0.8 mass of maleic anhydride is extruded and then shaped as a pipe with the same dimensions as that described in Example 1.

The flexural modulus, exudation and translucency of the sample based on PA-12 thus extruded and the extrudability of the pipe obtained are measured. The results are combined in Table 1.

EXAMPLE 5 (comparative) By way of comparison, a mixture comprising 70 weight of non-plasticised PA-6, the melting temperature of which is between 217 and 223°C 25 weight of ethylene-BA-maleic anhydride terpolymer with the molar composition 94.4/4.6/1 and with a melt index equal to 4.5 g/10 min, measured according to NFT standard 51-016 (190°C/load of 2.16 kg), 5 weight of copolymer of ethylene and of MA with the molar composition 94.4/5.6 is extruded and then shaped as a pipe with the same dimensions as that described in Example 1.

The flexural modulus, exudation and translucency of the sample based on PA-6 thus extruded and the extrudability of the pipe obtained are measured.

The results are combined in Table 1.

"Comprises/comprising" when used in this specification is taken to specify 0* 2 the presence of stated features, integers, steps or components but does not 9 99 preclude the presence or addition of one or more other features, integers, steps, S 15 components or group thereof. The terms "comprises" and "comprising" are to be considered synonymous with the terms "includes" and "including".

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a 0 0 0 0 C 0.t a 00050 *4 a A A Table 1 Example Flexural Flexural Exudation Translucency Extrudability Extrudability modulus of modulus of for an Maximum temperature the PA the extruder of the optimum alone composition output of extrusion curve (MPa) (MPa) 20 m/min (OC) 1 1,100 150-200 8-9 30 very good 240 2.a 1,100 150 28-30 30 very good 220-230 2.b 1,100 300-350 11-12 30 very good 240 2.c 1,100 1,100 0 30 very good 240 2.d 1,100 150-200 8-9 30 poor z 260 2.e 1,100 150-200 8-9 15 poor 260 2.f 1,100 150-200 8-S 15 poor 3 1,200 150-200 8-9 30 very good 240 4 1,200 200 8-9 15 good z 250 2,200 1,000-1,200 0 :swelling of the pipe; uncontrollable process

Claims

1. A translucent, flexible composition including: from 50 weight to 95 weight of at least one polyamide resin the light transmission of which through a sheet with a thickness of 1 mm at 700 nanometers is greater that from 5 weight to 50 weight of: at least one ethylene/alkyl (meth)acrylate/unsaturated dicarboxylic acid anhydride terpolymer and at least one ethylene/alkyl (meth)acrylate copolymer (III) wherein 2, and wherein the flexural modulus of said composition, measured according to ISO standard 178, is less than or equal to 2/3 of the flexural modulus of the PA resin alone and is less than 750 MPa. ea 0 0

02. The composition according to Claim 1, wherein said light transmission of said at least one polyamide resin is greater that 30% and wherein said flexural modulus of said composition is less than or equal to 1/3 of the flexural *0 modulus of the PA resin alone and is less than 500 MPa. o ooa

3. The composition according to Claim 1 or 2, which includes from te *0 weight to 90 weight of component and from 10 weight to 40 weight 1 2 of component and wherein

4. The composition according to any one of Claims 1 to 3, wherein component further includes one or more additives selected from the group consisting of stabilizers, mould-release agents, lubricants, crystallisation accelerators, pigments, organic and inorganic fillers and dyes, and antioxidising agents. 13 The composition according to any one of Claims 1 to 4, wherein component further Includes up to 50 weight of one or more plastlcising agents.

6. The composition according to Claim 5, wherein said plasticising agents include up to 20 weight of component

7. The composition according to any one of Claims 1 to 6, wherein said polyamide is selected from the group consisting of PA-11, PA-12, PA-12,12, and mixtures thereof.

8. The composition according to any one of Claims 1 to 7, wherein the alkyl (meth)acrylate units from which the terpolymer (II) and/or the copolymer (III) are derived are selected from the group consisting of methyl, ethyl, n-butyl, isobutyl, 0° 2-ethylhexyl, and cyclohexyl acrylates and methyl and ethyl methacrylates. oo,

9. The composition according to Claim 8, wherein said alkyl (meth)acrylate units are selected from the group consisting of ethyl acrylate, n-butyl acrylate, and methyl acrylate. 4

10. The composition according to Claim 1, wherein the unsaturated dlcarboxylic acid anhydride from which the terpolymer (II) is derived is maleic anhydride. S11. A process for the manufacture of a pipe which includes the steps of: melting a composition of any one of Claims 1 to 10 to form a molten mass, extruding said molten mass through a circular die to provide a tubular article, and cutting said tubular article transversely to form a length of pipe.

12. The method of claim 1, wherein said extrusion consists of single-layer Iextrusion. -V r 1% 0 a IMo -4 W i, 9t 4 49 9 99 9 9I 9 99 49 9) 69 9, 99

99.9 99 I 9 9 9 I 4I 9. 9 (4 9 4, I f 91O #9 t# 9 14 13. A flexible, translucent article of manufacture consisting of a pipe, a film, tubing, a sheet, or a fiber, wherein said article includes a composition as defined in any one of Claims 1 to 14. The article of manufacture of Claim 13, configured as a tubular pipe. A process for the conversion of a composition according to any one of Claims 1 to 10 by a technique for the conversion of thermo plastic materials. 16. The process according to Claim 15, wherein the conversion is effected by extrusion. 17. Materials obtained from a composition as defined in any one of claims 1 to 18. The material according to claim 17, which is translucent and flexible. DATED this 19th day of October 1998 ELF ATOCHEM SA WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA VAX DOC023 AU3798895.WPO LCG/JGC/RES ~jll ~11 ABSTRACT oooOooo FLEXIBLE TRANSLUCENT POLYAMIDE-BASED COMPOSITION, PROCESS FOR ITS CONVERSION AND ARTICLES OBTAINED FROM THIS COMPOSITION oooooo The invention relates to a translucent and flexible polyamide-based composition, which is easy to process, in particular by extrusion, comprising: from 50 weight to 95 weight 1) of at least one polyamide resin 2) of various additives (IV) such as stabilizers, mould-release agents, lubricants, crystallization accelerators, pigments, organic and/or inorganic fillers or dyes, or antioxidizing agents, 3) optionally of at least one plasticizing agent (V) 0* o .0.0 from 5 weight to 50 weight of at least one ethylene-alkyl (meth)- «tf acrylate-unsaturated dicarboxylic acid anhydride terpoly- mer (II), of at least one ethylene-alkyl (meth)acrylate me". copolymer (III) with 1/30 s s 2 and such that its flexural modulus, measured according to ISO standard 178, is less than or equal to 2/3 of the flexural modulus of the PA resin alone and is strictly less than 750 MPa. This composition has good extrudability and can W a be used to make many articles, in particular pipes. .f